AREA FORECAST DISCUSSION...UPDATED
NWS MOUNT HOLLY NJ
1035 AM EST SAT MAR 3 2007
.UPDATE /REST OF TODAY/...
CLOUDS ARE STARTING TO WORK THEIR WAY INTO THE REGION FROM CENTRAL
PENNSYLVANIA. SOME STRATOCU AND MORE SO SOME ALTOCU ARE CURRENTLY
INTO THE POCONOS AND LEHIGH VALLEY. WITH PLENTY OF SUNSHINE EARLY
THIS MORNING, TEMPERATURES RECOVERED NICELY OFF THEIR MORNING LOWS.
AT 900 AM...THE POCONOS WERE ALREADY IN THE 40S WITH MID 50S ACROSS
SOUTHERN NJ AND DELMARVA. I DIDN`T MAKE ANY SIGNIFICANT CHANGES TO
THE TEMPERATURES TODAY AS THE FORECAST WAS ALREADY CLOSER TO THE
WARMER ETA STAT GUIDANCE. WHILE THE CENTRAL AND SOUTHERN ZONES STILL
HAVE SOME ROOM TO WARM, THE FAR NORTHERN ZONES MAY PRETTY MUCH BE
DONE. CLOUDS ARE ON THE INCREASE, AS MENTIONED, AND BASED ON THE
SURFACE TEMP/DEWPOINT SPREAD AND VERTICAL SOUNDINGS, THERE`S A GOOD
CHANCE THAT SOME EVAPORATIVE COOLING WILL END UP AS PART OF THE
EQUATION THIS AFTERNOON. WITH THAT SAID, BOTH RAIN AND SNOW SHOWERS
WERE LEFT IN PLACE ACROSS THIS AREA. FURTHER TO THE SOUTH, NO CHANGE
IN PTYPE WAS MADE EITHER. I`LL STILL CALL IT LIQUID.
IN TERMS OF THE PRECIPITATION THREAT TODAY, WHILE THE ETA STAT
GUIDANCE WAS LARGELY PREFERRED FOR AFTERNOON TEMPERATURES, THE GFS
FIELDS, PARTICULARLY THE H8 FRONTOGENESIS FIELDS AT 12Z, WERE SPOT
ON AND PREFERRED. IT NICELY DEFINED TWO SEPARATE AREAS OF FORCING
WHICH MESHED VERY WELL WITH RADAR TRENDS. AS THE DAY PROGRESSES, THE
GFS CONSOLIDATES THE FORCING AS THE MID LEVEL TROF NEARS. THE CHANCE
POPS WERE KEPT IN PLACE WITH THE "BETTER" CHANCES REMAINING FURTHER
TO THE NORTH.
WITH VERTICAL MIXING IMPROVING OVER THE THE NEXT FEW HOURS, THE AREA
COULD SEE WINDS INCREASE AS THINGS GO ADIABATIC. THE 06Z GFS HAD
HIGHER WIND SPEEDS BETWEEN ~H9-H7 THEN COMPARED TO THE NAM. WHEN
COMPARED TO AREA 12Z RAOBS AND LOCAL ACARS DATA, THE LESS PRONOUNCED
NAM LOOKED MORE APPROPRIATE. WE`LL MAINTAIN THE PEAK GUSTS THIS
AFTERNOON AT 25 MPH. BEST CHANCES TO SEE THESE GUSTS WILL BE IN AND
AROUND THE SCATTERED CONVECTIVE SHOWERS THAT ARE EXPECTED TODAY.
HYDRO-WISE, NEW RFC GUIDANCE IS IN. WE`LL BE ABLE TO DROP THE
WARNINGS FOR THE ROCKAWAY AT BOONTON BELOW AND THE MILLSTONE AT
BLACKWELLS MILLS. WE`RE GOING TO WAIT FOR AFTERNOON GUIDANCE BEFORE
WE DO ANYTHING WITH PINEBROOK ON THE PASSAIC. THE RANCOCAS IS STILL
EXPECTED TO REMAIN BELOW FLOOD STAGE.
KRUZDLO
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST SUNDAY FOR ANZ450>455.
$$
.SYNOPSIS...
STRONG SHORT WAVE TROUGH TO MOVE OUT OF NORTHEAST U.S. OVER NEXT
48 HOURS. NW FLOW IN WAKE OF TROUGH WILL USHER IN ANOTHER SHOT OF
WINTER TYPE TEMPERATURES FOR EARLY NEXT WEEK. TEMPERATURES
MODERATE LATER IN THE WEEK AS FLOW PATTERN OVER U.S. BECOMES MORE
ZONAL.
&&
.SHORT TERM /TODAY THROUGH MONDAY NIGHT/...
TO THUNDER OR NOT TO THUNDER...THAT IS THE QUESTION. HAVE
CONTINUED WITH PREVIOUS FORECAST MENTIONING CHANCE OF
PRECIPITATION MAINLY FOR THE AFTERNOON HOURS AS SHORT WAVE WITH
VERY COLD TEMPERATURES ALOFT ROTATES OVER THE FORECAST AREA. HAVE
KEPT THUNDER OUT OF THE FORECAST ON THIS PACKAGE AS WAS NOT
CONVINCED WE HAVE ENOUGH PARAMETERS COMING TOGETHER. HOWEVER SPC
STILL HAS GENERAL THUNDER OVER THE REGION FOR TODAY. SOUNDINGS DO
FAVOR SOME STRONG GUSTY WINDS WITH ANY CONVECTIVE SHOWERS WHICH
DEVELOP. WILL MENTION POTENTIAL FOR STRONG WIND GUSTS TODAY WITH
SHOWERS IN THE HWO.
COOLER AIRMASS MOVES INTO THE REGION ON SUNDAY IN THE WAKE OF THE
SHORTWAVE. DID NOT MAKE ANY SIGNIFICANT CHANGES TO PREVIOUS
FORECAST IN THIS TIME FRAME. NEXT FRONTAL BOUNDARY APPROACHES LATE
MONDAY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
LONG TERM PERIOD STARTS OFF IN WINTER AS ANOTHER SHOT OF ARCTIC
AIR COMES SURGING INTO THE REGION. BOTH 18Z AND 00Z GFS MODEL RUNS
TAKE SHORTWAVE MOVING THRU THE REGION TUE NIGHT AND WED AS A
CLIPPER TYPE SYSTEM WITH LIGHT QPF AMOUNTS. DID NOT MAKE A CHANGE
TO THE FORECAST FOR THIS FEATURE BUT IT BEARS WATCHING FOR
CONTINUED MODEL CONTINUITY. TEMPERATURES REBOUND TOWARD THE END OF
THE PERIOD AS FLOW ALOFT BECOMES MORE ZONAL.
&&
.AVIATION /09Z-06Z/...
CURRENTLY THE MAJORITY OF OUR AREA IS VFR UNDER CLEAR SKIES AND
GOOD VSBYS, IN BETWEEN CI TO OUR S/SE AND AC TO OUR W/NW. THE AC
HAS MOVED INTO THE LEHIGH VALLEY AND WILL CONTINUE TO PUSH SLOWLY
E THROUGH THE MORNING HOURS. AS THE FRONTAL ZONE MOVES IN, CIGS
WILL LOWER TO SC AND WE MAY EVEN HAVE SOME MVFR CONDITIONS IN
LATE DAY SHOWERS.
&&
.MARINE...
WINDS HAVE DROPPED OFF BUT SEAS ARE STILL QUITE HIGH. THEY`RE
ACTUALLY RUNNING AT OR SLIGHTLY HIGHER THAN WAVEWATCH. WITH THIS
IN MIND, WE WILL SEE THE WAVE HEIGHTS LOWER TODAY BUT PROBABLY
NOT BELOW SMALL CRAFT ADVISORY CRITERIA BEFORE THE FRONTAL ZONE
CROSSES THE AREA AND WINDS PICK UP FROM A WNW DIRECTION. EXPECT
GUSTS TO AROUND 25 KT TONIGHT AND SUNDAY. WILL CARRY THE SCA
THROUGH SUNDAY FOR NOW. THEY MIGHT EVEN GO INTO SUNDAY NIGHT,
BUT SINCE THATS THE 4TH PERIOD, I WON`T GO THERE.
&&
.HYDROLOGY...
THE BULK OF THE FLOODING HAS ALREADY OCCURRED HOWEVER SEVERAL
SPOTS OF FLOODING ARE ONGOING. PLEASE CHECK THE LATEST FLOOD
WARNINGS /FLWPHI/ AND FLOOD STATEMENTS /FLSPHI/ FOR THE LATEST
INFORMATION. PLEASE USE EXTREME CAUTION AROUND CREEKS AND STREAMS
AS THE WATER FLOW HAS BEEN ENHANCED DUE TO ALL THE RUNOFF. ALL
WATERWAYS WILL BE CLOSELY MONITORED AS THEY CREST AND ALSO ANY
OTHER POSSIBLE RISES TAKE PLACE. NO ADDITIONAL SIGNIFICANT
PRECIPITATION IS EXPECTED THROUGH EARLY NEXT WEEK.
&&
$$
SYNOPSIS...
SHORT TERM...SZATKOWSKI
LONG TERM...SZATKOWSKI
AVIATION...RPW
MARINE...RPW
HYDROLOGY...RPW/SZATKOWSKI
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
309 PM CST SUN MAR 4 2007
.DAYS 1-2...
THE MAIN FORECAST CHALLENGES ARE HIGH TEMPERATURES ON TUESDAY WITH
COLD FRONT.
UPPER LEVEL RIDGING AND DOWNSLOPE WARMING WILL CONTINUE TO BRING
WARMER TEMPS INTO WESTERN KANSAS INTO MONDAY THEN AS A NORTHERN
BRANCH SHORTWAVE TROUGH PUSHES ACROSS THE UPPER MIDWEST A COLD
FRONT WILL TRY TO BACKDOOR INTO THE HAYS AREA ON MONDAY NIGHT AND
TUESDAY WITH SOME POSSIBLE STRATUS OR FOG FORMING. THIS FRONT WILL
CONTINUE ON TUESDAY AND MAY AFFECT HIGH TEMPS IN THE NORTH SO HAVE
LOWERED HIGHS IN THE NORTH INTO THE MID 50S. OTHERWISE FOR TONIGHT
LOOK FOR PLENTY OF CLEAR SKIES WITH A FEW CIRRUS CLOUDS LATE AND
LOWS IN THE MID TO UPPER 20S. THEN FOR MONDAY THE CIRRUS CLOUDS
INCREASE WITH SKIES BECOMING PARTLY CLOUDY WITH HIGHS IN THE 60S.
IF THE CIRRUS IS THICK ENOUGH IT COULD KEEP HIGHS DOWN A BIT. THEN
FOR MONDAY NIGHT INTO TUESDAY A BACKDOOR MODIFIED ARCTIC BOUNDARY
MOVES INTO THE NORTH CWA WITH MAYBE SOME FOG AND LOWS IN THE UPPER
20S TO LOWER 30S LOOKS REASONABLE. HIGHS ON TUESDAY COULD BE
TRICKY BASED ON IF ANY FOG FORMS AND HOW LONG IT LASTS AND HOW
MUCH MODIFICATION THIS ARCTIC BOUNDARY GOES THROUGH. WILL GO WITH
MID 50S NORTH TO NEAR 70 AT MEDICINE LODGE. WINDS THROUGH THE
PERIOD SHOULD BE LIGHT.
.DAYS 3-7...
THE MEDIUM RANGE DETERMINISTIC MODELS ALL SEEM TO BE IN PRETTY GOOD
AGREEMENT REGARDING THE UPPER FLOW PATTERN IN THE 3 TO 7 DAY TIME
FRAME. A MUCH QUIETER REGIME HAS SET IN ACROSS MUCH OF THE UNITED
STATES FOLLOWING A WEEK OF ACTIVE WEATHER THE LAST PART OF FEBRUARY
INTO THE FIRST COUPLE DAYS OF MARCH. THIS PROGRESSIVE, MORE ZONAL
REGIME OVER THE CONUS IS FORECAST TO CONTINUE AT LEAST THROUGH THE
NEXT 7 TO 10 DAYS. A SERIES OF WAVES WILL MOVE ACROSS THE CENTRAL
PLAINS DURING THE PERIOD BUT WILL BE FOR THE MOST PART LACKING DEEP
LAYER MOISTURE UNTIL THEY GET EAST OF MY AREA. THIS IS NO SURPRISE
HERE AS THIS IS TYPICAL IN A PROGRESSIVE FLOW REGIME.
A VERY WEAK WAVE WILL RIPPLE ACROSS THE PLAINS MIDWEEK, BUT WILL NOT
HAVE MUCH OF AN EFFECT ON OUR WEATHER. WHAT WILL BE MORE NOTICEABLE
IS A WEAK COLD FRONT WHICH IS FORECAST TO SLIDE SOUTH ACROSS WESTERN
KS TUESDAY NIGHT. THIS SHOULD HOLD TEMPS DOWN FOR WEDNESDAY. THE
FRONT SHOULD RETURN BACK NORTH OR WASH OUT ON THURSDAY. TEMPERATURES
SHOULD BE WARM ON THURSDAY AS WE RETURN TO THE WARM SECTOR WITH GOOD
DOWNSLOPE FLOW AHEAD OF THE NEXT FRONT. THE EAST MAY STAY COOLER IF
LOW STRATUS HANGS ON. THERE IS A VERY SMALL CHANCE OF AN ISOLATED
STORM ALONG THE DEVELOPING DRYLINE ACROSS CENTRAL KS DURING THE
AFTERNOON AS LOW LVL MOISTURE FINALLY BEGINS TO RETURN AFTER BEING
WIPED OUT. HOWEVER, THE QUALITY OF THIS MOISTURE RETURN IS IN
QUESTION AND STORMS DON`T TYPICALLY DEVELOP ALONG THE DRYLINE IN
MARCH UNLESS THERE IS SOME UPPER SUPPORT. THERE COULD BE SOME
ELEVATED STORMS THURSDAY NIGHT BUT THIS ACTIVITY SHOULD BE OFF TO MY
EAST. WILL LEAVE THIS PART OF THE FORECAST DRY.
THE NEXT STRONGER SHORTWAVE TROF MOVES ACROSS THE PLAINS ON FRIDAY
WHICH WILL PUSH ANOTHER PACIFIC COLD FRONT THROUGH WESTERN KS. WITH
ALL OF THE GOOD MOISTURE ALREADY BEING SHUNTED TO THE SOUTH AND
EAST, THIS SYSTEM WILL MOST LIKELY BE MOISTURE STARVED SO WILL LEAVE
IN ONLY SILENT POPS AND KEEP THE FORECAST DRY. ANOTHER PIECE OF
ENERGY SLICES SOUTHEAST ACROSS KANSAS ON SATURDAY IN THE WAKE OF THE
FRIDAY SYSTEM BUT ONCE AGAIN DO NOT SEE ANY REASON TO PUT PRECIP IN
THERE DUE TO LACK OF MOISTURE.
THE 04/00Z ECMWF WAS QUITE A BIT WARMER THAN THE 04/12Z GFS FROM
WEDNESDAY ON. IN GENERAL I TOOK THE MIDDLE ROAD BETWEEN THE TWO
SOLUTIONS AND DID NOT VARY MUCH FROM THE HPC GUIDANCE. THE MAIN
CHANGE WAS TO INCREASE HPC GUIDANCE TEMPS ON THURSDAY FOR THE
REASONS STATED EARLIER. AFTER A COOLER FRIDAY BEHIND THE PACIFIC
FRONT, THE WARMING TREND SHOULD BEGIN SLOWLY ON SATURDAY WITH THE
TRAILING WAVE MOVING THROUGH. DOWNSLOPE FLOW WILL KICK IN THEREAFTER
AS SHORTWAVE RIDGING BUILDS IN THE HIGH PLAINS. SUNDAY AND MONDAY OF
NEXT WEEK WILL BE QUITE WARM, POSSIBLY MAKING THE 70 DEGREE MARK,
AHEAD OF YET ANOTHER PACIFIC FRONT ON DAY 9. I WILL KEEP THE GOING 8
TO 10 DAY FORECAST OF ABOVE AND BELOW FOR TEMPS AND PRECIP
RESPECTIVELY INTACT AS THERE ARE STILL NO DISCERNIBLE SIGNS OF
PRECIP OR COLD AIR HEADED OUR WAY.
&&
.AVIATION...
BREEZY NORTHWEST WINDS THIS AFTERNOON SHOULD BACK OFF
TO LGT AND VRB BY 00Z AND WILL REMAIN THIS WAY THROUGH THE DAY ON
MONDAY.
NO IMPACT TO AIRCRAFT OPERATIONS IS EXPECTED AS VFR CONDITIONS ARE
EXPECTED TO CONTINUE FOR THE NEXT 24 HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 27 64 30 63 / 0 0 0 0
GCK 26 61 28 59 / 0 0 0 0
EHA 30 62 32 63 / 0 0 0 0
LBL 27 64 31 64 / 0 0 0 0
HYS 26 59 28 55 / 0 0 0 0
P28 28 68 32 67 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN06/27
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1230 AM EST SAT MAR 3 2 2007
.AVIATION (06Z TAFS)...
WINDS DIMINISHED OVER CENTRAL KENTUCKY AND SOUTH CENTRAL INDIANA
THIS EVENING WITH MOST SPEEDS BETWEEN 6 AND 10 KTS. PRESSURE
GRADIENT WILL NOT WEAKEN MUCH OVERNIGHT AND EXPECT WINDS TO STAY
BETWEEN 5 AND 10 KTS OVERNIGHT.
SOME LIGHT RADAR RETURNS PERSIST OVER LMK/S EASTERN COUNTIES BUT NO
REPORTS OF ANY PRECIPITATION REACHING THE GROUND. CLOUDS ARE MOSTLY
MID LEVEL (9-11 THSD FT) OVER CWA AND WILL INDICATE THIS IN TAFS.
MAIN CONCERN FOR DAYTIME ON SATURDAY WILL BE CLOUDS AND ANY
PRECIPITATION ACCOMPANYING TROUGH (UPPER LEVEL AND SURFACE) THAT
WILL PUSH INTO THE AREA LATE MORNING INTO THE AFTERNOON. EXPECT
CLOUDS AND TROUGH TO REACH SDF FIRST THEN LEX AND BWG 1 TO 2 HOURS
LATER.
WINDS WILL INCREASE LATE MORNING AS DAYTIME HEATING ALLOWS HIGHER
WINDS ALOFT TO MIX DOWN TO SURFACE. LAPSE RATES EXPECTED TO REMAIN
STEEP...ESPECIALLY AFTER LATE MORNING...CREATING ENOUGH INSTABILITY
FOR SCATTERED SHOWERS TO DEVELOP. MORE MOISTURE IS AVAILABLE
TODAY THAN ON FRIDAY SO EXPECT CLOUDS AND SOME SHOWERS TO DEVELOP.
MOST OF THESE CLOUDS WILL BE IN THE 3 TO 4 THSD FOOT RANGE.
SCHOLZ
&&
.UPDATE...
STRONG WINDS AT LEX HAVE BEEN MORE PERSISTENT THAN EXPECTED
EARLIER...AND HAVE ISSUED ANOTHER SPS FOR THE BLUEGRASS THROUGH 1030
PM EST TO COVER THESE GUSTS. SHOULD SEE A DIMINISHING TREND
AFTERWARD. IN OTHER SECTIONS OF THE CWA WINDS HAVE SUBSIDED.
AREA OF MID/HIGH LEVEL CLOUDS CURRENTLY OVER THE CWA ASSOC WITH
UPPER LEVEL JET STREAK ARE PRODUCING SOME DECENT RADAR RETURNS OVER
SRN/ERN PARTS OF THE CWA. EVEN IN THE PRESENCE OF 25-30 DEGREE T-TD
SPREADS...FEEL THAT AT LEAST SOME SPRINKLES ARE POSSIBLE THROUGH THE
EARLY OVERNIGHT PERIOD IN THESE AREAS. WILL UPDATE THE FCST TO
ACCOUNT FOR THIS.
BASED ON LATEST OUTPUT FROM NAM/RUC...PCPN ASSOC WITH VIGOROUS UPPER
WAVE OVER MIDWEST SHOULD HOLD OFF UNTIL MID-DAY SATURDAY...WHICH IS
IN-LINE WITH CURRENT FCST.
UPDATED FCST OUT BY 10 PM EST.
CS
&&
.SHORT TERM (TONIGHT AND SATURDAY)
SOME MAJOR PROBLEMS TO DEAL WITH IN THE SHORT TERM. FIRST AND
FOREMOST IS THE STRONG AND GUSTY WINDS THIS AFTERNOON AND EVENING.
A TIGHT PRESSURE GRADIENT AROUND THE DEEP GREAT LAKES LOW PRESSURE
IS CAUSING WIND GUSTS FROM 40 TO 50 MPH AT TIMES ACROSS N CNTRL KY
AND S CNTRL INDIANA THAT WILL DIMINISHING DURING THE EVENING HOURS.
SO KEPT THE WIND ADVISORY ACROSS THE SAME AREA UNTIL 00Z TONIGHT.
ON SATURDAY AS THE CLOSED 500 MB LOW OVER STARTS TO LIFT EAST
NORTHEAST TOWARDS SOUTHERN CANADA...A RATHER VIGOROUS SHORT WAVE
ROTATES AROUND THE SOUTH SIDE AROUND THIS CLOSED CIRCULATION AND
BRINGS A BURST OF COLDER AIR THAT IS RELATIVELY MOIST IN THE LOWER
LEVELS UP TO ABOUT THE 700 MB LEVEL. THERE IS ALSO SOME DECENT
SYNOPTIC SCALE LIFT...SO THERE IS AT LEAST A CHANCE OF RAIN OR SNOW
ON SATURDAY. WILL GO WITH 30 PERCENT NRN TWO THIRDS OF FA AND 20 PCT
ACROSS THE SOUTH.
WITH INCREASED CLOUDS AND PCPN THREAT ALONG WITH GOOD COLD AIR
ADVECTION...WILL GO WITH MAX TEMPS A FEW DEGS BELOW THE MAV FCSTS FOR
SATURDAY. THIS AGREES WELL WITH IND..ILN AND PAH FCSTS TOO. --21
.LONG TERM (SATURDAY NIGHT THROUGH FRIDAY)...
MEDIUM AND LONG TERM MODELS HAVE BEEN FAIRLY CONSISTENT THE LAST FEW
DAYS...LATEST DAY 5 AND 6 VERIFICATION SCORES SHOW THE CANADIAN
LEADING THE PACK THE LAST TWO DAYS WITH THE EURO AND GFS JUST
BEHIND. GFS HAS BEEN SOLID THROUGH DAY 5...WILL FOLLOW THERE AND
THEN LEAN TOWARDS THE EURO THROUGH THE REST OF THE PERIOD...IT HAS
BEEN STABLE AND HAS MUCH SUPPORT FROM THE HIGH PERFORMING CANADIAN.
SATURDAY NIGHT THROUGH MONDAY...
UPPER LEVEL TROUGH ROTATING THROUGH THE FORECAST AREA SATURDAY NIGHT
WILL CREATE SOME FORCING...ALONG WITH A MODEST AMOUNT OF MOISTURE
THROUGH THE COLUMN...WILL ALLOW FOR CHANCE OF SNOW SHOWERS THROUGH
THE NIGHT. LITTLE ACCUMULATION...BUT A SLIGHT WHITENING OF SURFACES
LOOKS POSSIBLE. MUCH DRIER AIR STARTS TO ADVECT INTO THE OHIO VALLEY
EARLY SUNDAY FROM THE WEST AS THE UPPER LEVEL TROUGH MOVES EAST OF
THE APPALACHIANS. COLD DAY SUNDAY WITH THE COMBO OF H850 TEMPS NEAR
-10C AND SOME LINGERING CLOUDS EARLY...BUT WILL GIVE FINALLY TO
ALLOW FOR A MOSTLY SUNNY AFTERNOON. BOTH SATURDAY NIGHT AND SUNDAY
MAY BE SOMEWHAT BREEZY WITH SOME GUSTS NEAR 25 MPH POSSIBLE.
SLIGHT WAA DEVELOPS LATE SUNDAY AS SURFACE HI SHIFTS FROM THE
SOUTHERN ROCKIES INTO THE WESTERN GULF STATES BRINGING WARMER AIR IN
FROM THE PLAINS. H850 TEMPS CLIMB TO AROUND +2C BY MONDAY AFTERNOON
AND NEAR FULL SUN...TEMPS WILL CLIMB BACK TO SEASONAL EARLY MARCH
LEVELS.
TUESDAY THROUGH FRIDAY
AREA SANDWICHED BETWEEN THE RIDGING ACROSS THE WESTERN PLAINS AND
THE NORTHEASTERN TROUGH...CREATING A WNW FLOW OVER THE OHIO VALLEY.
TROUGH CONTINUES TO SLOWLY MOVE FURTHER EAST OFF THE COAST WITH
INCREASING HEIGHTS OVER THE OHIO VALLEY INTO THURSDAY AS THE RIDGING
FLATTENS AND DRIFTS EAST TOWARDS THE REGION. PATTERN BECOMES NEARLY
ZONAL OVER THE ENTIRE CONUS BY FRIDAY.
BACKDOOR COLD FRONT LOOKS TO PUSH INTO OR NEAR THE FORECAST AREA
TUESDAY...AS LARGE SURFACE HIGH MOVES FROM JUST SOUTH OF HUDSON BAY
INTO THE NORTHEAST BY WEDNESDAY MORNING. TEMPS MAY EB SLIGHTLY
COOLER TUESDAY THAN MONDAY AS A FEW MORE CLOUDS AND SLIGHTLY COOLER
AIR ALOFT WORKS INTO THE MID OHIO VALLEY. AS THE RIDGING MOVES MORE
INTO THE AREA ALONG WITH A MORE SOUTHERLY FLOW WEDNESDAY INTO
THURSDAY TEMPS LOOKS TO BE ABOVE NORMAL EACH DAY WITH PLENTY OF
SUNSHINE.
COLD FRONT LOOKS TO BE POISED TO DROP INTO THE FORECAST AREA ON
FRIDAY...AS CLOUDS INCREASE EARLY. AREA OF LOW PRESSURE WILL DEVELOP
ACROSS THE SOUTHERN PLAINS AND MOVE UP THROUGH THE REGION DURING THE
DAY...WITH BEST PRECIP CHANCES LOOKING TO BE IN THE AFTN/EVEN.
TEMPERATURES DO NOT LOOK AS COOL BEHIND THE FRONT AS THEY DID THE
LAST FEW RUNS...WHICH GOES INLINE BETTER WITH THE LATEST
INDICES(PNA/NAO/EPO). THEY CONTINUE TO INDICATE THE PERIOD THROUGH
THE MIDDLE OF MONTH SHOULD FAVOR AT LEAST NORMAL TO SLIGHTLY ABOVE
NORMAL.
SCHOTT
&&
.AVIATION (00Z TAFS)...
IMPRESSIVE WINDS THIS AFTERNOON OVER THE ENTIRE CWA WITH GUSTS AS
HIGH AS 46KTS AT KLEX AROUND 21Z. STEEP LAPSE RATES UP TO 600MB ON
RECENT ACARS SOUNDINGS FROM KSDF...MORE REMINISCENT OF SOUNDINGS
SEEN IN THE HIGH PLAINS DURING THE SUMMER. WINDS ARE FCST TO DROP
OFF DRAMATICALLY BETWEEN 0Z-2Z THIS EVENING PER LATEST RUC.
EVEN WITH SCT RADAR RETURNS...LITTLE IF ANY PRECIP FCST TO REACH THE
SFC THIS EVENING GIVEN TEMP-DWPT SPREADS ON THE ORDER OF 35 DEGREES.
THEY WOULD CERTAINLY NOT BE ENOUGH TO RESTRICT VSBYS AT TAF
SITES...BUT ANY VIRGA WOULD BE CAPABLE OF PRODUCING LOCALIZED
DOWNDRAFTS.
VERY LATE TONIGHT...BUT MORE SO TOMORROW...CHCS FOR -SHRA ARE
FCST...WITH A FEW -SHSN POSSIBLE AT SDF/LEX TERMINALS DURING THE
AFTN AS BOUNDARY LAYER COOLS PER NAM FCST SOUNDINGS. WILL HANDLE
WITH VCSH FOR TIME BEING DUE TO UNCERTAINTIES IN COVERAGE.
CS
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
955 PM EST SUN MAR 4 2007
.EVENING UPDATE...
LWRD MIN TEMPS 1 OR 2 DEGS AND DECREASED CLOUD COVER EAST OF THE
BLUE RIDGE AND IN CENTRAL VA PER LTST SAT TRENDS. OTHERWISE...NO
MAJOR CHGS NECESSARY. CRITICAL FIRE WEATHER STILL LIKELY TO BE AN
ISSUE MON AFTN AND EVNG. STRONG WINDS ON MON ALSO STILL EXPECTED.
JB
&&
.SHORT TERM /TODAY THROUGH MONDAY/...
ATER VAPOR LOOP SHOWS A POSITIVELY TILTED TROUGH ELONGATING FROM
THE MID ATLANTIC THROUGH THE PLAINS. ACARS 400-250MB WIND
OBSERVATIONS REVEAL A 160-190KT SOUTHWESTERLY JET FROM THE PLAINS
THROUGH THE MID ATLANTIC. 11Z SURFACE ANALYSIS PLACED A COLD FRONT
FROM THE ATLANTIC WATERS SOUTHWEST THROUGH THE CAROLINAS. A 1034MB
ANTICYCLONE DOMINATED TEXAS AND THE PLAINS. THE NEXT SYSTEM
CONTINUES TO ORGANIZE ACROSS SOUTH CENTRAL CANADA.
SNOW SHOWERS WILL CONTINUE TO DIMINISH ACROSS THE MOUNTAINS LATE
THIS AFTERNOON AND EVENING. MEANWHILE EXPECT DIURNAL CUMULUS FORCED
BY THE COLD POOL ASSOCIATED WITH THE MID LEVEL TROUGH OVERHEAD TO
DECAY. CONTINUED COLD ADVECTION SHOULD MAINTAIN WIND GUSTS THROUGH
THE EVENING HOURS (OVERNIGHT IN THE HIGHEST TERRAIN)...BEFORE
DECOUPLING. STUCK CLOSE TO MAV GUIDANCE TONIGHT AS ITS BEEN VERY
CONSISTENT DURING THE LAST TEN RUNS.
IMPROVED CONDITIONS EXPECTED MONDAY WITH THE PASSAGE OF THE MID
LEVEL TROUGH...ALTHOUGH THE PRESSURE GRADIENT AND DEPTH OF MIXING
SHOULD ALLOW WIND GUSTS TO INCREASE THROUGH THE DAY. WIND GUSTS MAY
APPROACH WIND ADVISORY CRITERIA...ESPECIALLY ALONG AND WEST OF THE
BLUE RIDGE DURING THE AFTERNOON. MOMENTUM TRANSFER VALUES OF
40-44KTS FROM 12Z NAM/GFS BUFKIT FORECAST SOUNDINGS IS BORDERLINE
CONSIDERING IMPACT OF FRICTION.
THE NEXT SHARP COLD FRONT...ASSOCIATED WITH A COMPACT SHORT WAVE
DROPPING SOUTHEAST FROM SOUTH CENTRAL CANADA...WILL BE NEARING THE
MARYLAND BORDER FROM THE NORTH BY EVENING. HAVE THE REDEVELOPMENT OF
SNOW SHOWERS NEAR THE MOUNTAINS AS A RESULT.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
NO MAJOR STORM SYSTEMS TO TALK ABOUT IN THE LONG TERM TODAY. STRONG
CAA PUSH BEGINS IN EARNEST. THINK THIS WILL BE ENOUGH TO KEEP
STRONGER WINDS GOING ALL NIGHT MON NIGHT WITH STEEP LAPSE RATES IN
THE BOUNDARY LAYER BELOW THE SUBSIDENCE IVERSION. WILL KEEP MENTION
OF 35KT GUSTS THROUGHOUT THE NIGHT.
COLD ADVECTIVE PUSH ON NORTHWEST WINDS SHOULD START THE SNOW SHOWERS
UP AGAIN ON THE ALLEGANY RIDGE IN THE NORTHWEST...BUT TRAJECTORIES
NOT OPTIMAL FOR GOOD SN ACCUMS. FOR NOW WL KEEP MENTION OF AN INCH
OR LESS FOR MON NIGHT.
FAST FLOW PUSHES THE RIDGE OVERHEAD AND OFFSHORE ON TUES AHEAD OF
NEXT CLIPPER SYSTEM TO CROSS THE AREA WED. TEMPS TRENDING COLDER FOR
THE DAYTIME HRS WED. TIMING NOT OPTIMAL FOR ANY ACCUMULATING SNOW AS
THE SYSTEM WILL BE CROSSING RIGHT THROUGH THE MIDDLE OF THE CWFA.
FOR NOW WILL MENTION RA ACROSS THE SOUTH AND SN ACROSS THE NORTH
WITH A NARROW ZONE OF RASN ACROSS THE MIDDLE. SHOULD THE SYSTEM TAKE
A MORE SOUTHERLY TRACK WILL HAVE TO REVISIT THE RA/SN LINE AND
ADJUST A BIT COOLER.
COOL WX CONTS THEREAFTER BEFORE NEXT PCPN EVENT COMES DURING THE DAY
SAT AS A COLD FRONT APCHS FROM THE WEST. THIS SYS LOOKS WARM ENOUGH
FOR PCPN TO BE IN THE FORM OF RAIN.
&&
.AVIATION /20Z-18Z/...
CUMULUS WILL DECAY LATE THIS AFTERNOON AND EVENING. EXPECT WINDS TO
SLOWLY DECOUPLE DURING THE AFTERNOON HOURS. MIXING MID MONDAY
MORNING SHOULD ALLOW FOR 30KT WIND GUSTS UNDER SKC-FEW050 SKIES.
&&
.MARINE...
12Z ETA/GFS MOS AT THOMAS POINT INDICATE SUSTAINED WINDS WILL FALL
TO 10KT TONIGHT BEFORE RISING INTO THE 20-25KT RANGE MONDAY. 12Z
NAM/GFS PROXIMITY FORECAST SOUNDINGS INDICATE WIND GUST POTENTIAL OF
20-25KTS TONIGHT...INCREASING TO 35KTS BY LATE MONDAY AFTERNOON.
GALES TO START THE PERIOD FOR MON NIGHT. SCA CONDS MAY CONTINUE FOR
PART OF THE DAY TUES AND WILL HIGHLIGHT THIS IN THE SYNOPSIS.
&&
.FIRE WEATHER...
WITH RELATIVE HUMIDITY LEVELS FORECAST TO DROP TO 20 PERCENT...30-40
MPH WIND GUSTS...AND DRYING FUEL MOISTURE...HAVE ISSUED A FIRE
WEATHER WATCH FOR NORTH CENTRAL VIRGINIA AND LOWER SOUTHERN MARYLAND
LATE DURING MONDAY MORNING THROUGH THE AFTERNOON. FUEL MOISTURE WAS
USED TO DELINEATE THE AREA...WHILE FORECAST RELATIVE HUMIDITY LEVELS
WERE USED TO TIME THE WATCH (AS WINDS WILL PERSIST THROUGH THE
NIGHT).
&&
.HYDROLOGY...
MAIN STEM FORECAST POINTS ARE ALL UNDER FLOOD STAGE.
&&
.TIDES...
CURRENT TIDAL DEPARTURES LESS THAN A FOOT ABOVE ASTRONOMICAL
PREDICTIONS. THE LUNAR CYCLE IS AT A FULL MOON (99 PERCENT FULL).
THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM INDICATES WATER
LEVELS WILL FALL TO NEAR ASTRONOMICAL PREDICTIONS THROUGH THIS
EVENING.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...FIRE WEATHER WATCH FROM MONDAY MORNING THROUGH MONDAY
AFTERNOON FOR MDZ016>018.
VA...FIRE WEATHER WATCH FROM MONDAY MORNING THROUGH MONDAY
AFTERNOON FOR VAZ025>027-029-030-036>041-050-051-055>057.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EST MONDAY FOR ANZ530>537.
GALE WARNING FROM 3 PM MONDAY TO 6 AM EST TUESDAY FOR
ANZ530>537.
&&
$$
SHORT TERM...ROGOWSKI
LONG TERM...MANNING
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
315 PM EST SUN MAR 4 2007
.SHORT TERM /TODAY THROUGH MONDAY/...
ATER VAPOR LOOP SHOWS A POSITIVELY TILTED TROUGH ELONGATING FROM
THE MID ATLANTIC THROUGH THE PLAINS. ACARS 400-250MB WIND
OBSERVATIONS REVEAL A 160-190KT SOUTHWESTERLY JET FROM THE PLAINS
THROUGH THE MID ATLANTIC. 11Z SURFACE ANALYSIS PLACED A COLD FRONT
FROM THE ATLANTIC WATERS SOUTHWEST THROUGH THE CAROLINAS. A 1034MB
ANTICYCLONE DOMINATED TEXAS AND THE PLAINS. THE NEXT SYSTEM
CONTINUES TO ORGANIZE ACROSS SOUTH CENTRAL CANADA.
SNOW SHOWERS WILL CONTINUE TO DIMINISH ACROSS THE MOUNTAINS LATE
THIS AFTERNOON AND EVENING. MEANWHILE EXPECT DIURNAL CUMULUS FORCED
BY THE COLD POOL ASSOCIATED WITH THE MID LEVEL TROUGH OVERHEAD TO
DECAY. CONTINUED COLD ADVECTION SHOULD MAINTAIN WIND GUSTS THROUGH
THE EVENING HOURS (OVERNIGHT IN THE HIGHEST TERRAIN)...BEFORE
DECOUPLING. STUCK CLOSE TO MAV GUIDANCE TONIGHT AS ITS BEEN VERY
CONSISTENT DURING THE LAST TEN RUNS.
IMPROVED CONDITIONS EXPECTED MONDAY WITH THE PASSAGE OF THE MID
LEVEL TROUGH...ALTHOUGH THE PRESSURE GRADIENT AND DEPTH OF MIXING
SHOULD ALLOW WIND GUSTS TO INCREASE THROUGH THE DAY. WIND GUSTS MAY
APPROACH WIND ADVISORY CRITERIA...ESPECIALLY ALONG AND WEST OF THE
BLUE RIDGE DURING THE AFTERNOON. MOMENTUM TRANSFER VALUES OF
40-44KTS FROM 12Z NAM/GFS BUFKIT FORECAST SOUNDINGS IS BORDERLINE
CONSIDERING IMPACT OF FRICTION.
THE NEXT SHARP COLD FRONT...ASSOCIATED WITH A COMPACT SHORT WAVE
DROPPING SOUTHEAST FROM SOUTH CENTRAL CANADA...WILL BE NEARING THE
MARYLAND BORDER FROM THE NORTH BY EVENING. HAVE THE REDEVELOPMENT OF
SNOW SHOWERS NEAR THE MOUNTAINS AS A RESULT.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
NO MAJOR STORM SYSTEMS TO TALK ABOUT IN THE LONG TERM TODAY. STRONG
CAA PUSH BEGINS IN EARNEST. THINK THIS WILL BE ENOUGH TO KEEP
STRONGER WINDS GOING ALL NIGHT MON NIGHT WITH STEEP LAPSE RATES IN
THE BOUNDARY LAYER BELOW THE SUBSIDENCE IVERSION. WILL KEEP MENTION
OF 35KT GUSTS THROUGHOUT THE NIGHT.
COLD ADVECTIVE PUSH ON NORTHWEST WINDS SHOULD START THE SNOW SHOWERS
UP AGAIN ON THE ALLEGANY RIDGE IN THE NORTHWEST...BUT TRAJECTORIES
NOT OPTIMAL FOR GOOD SN ACCUMS. FOR NOW WL KEEP MENTION OF AN INCH
OR LESS FOR MON NIGHT.
FAST FLOW PUSHES THE RIDGE OVERHEAD AND OFFSHORE ON TUES AHEAD OF
NEXT CLIPPER SYSTEM TO CROSS THE AREA WED. TEMPS TRENDING COLDER FOR
THE DAYTIME HRS WED. TIMING NOT OPTIMAL FOR ANY ACCUMULATING SNOW AS
THE SYSTEM WILL BE CROSSING RIGHT THROUGH THE MIDDLE OF THE CWFA.
FOR NOW WILL MENTION RA ACROSS THE SOUTH AND SN ACROSS THE NORTH
WITH A NARROW ZONE OF RASN ACROSS THE MIDDLE. SHOULD THE SYSTEM TAKE
A MORE SOUTHERLY TRACK WILL HAVE TO REVISIT THE RA/SN LINE AND
ADJUST A BIT COOLER.
COOL WX CONTS THEREAFTER BEFORE NEXT PCPN EVENT COMES DURING THE DAY
SAT AS A COLD FRONT APCHS FROM THE WEST. THIS SYS LOOKS WARM ENOUGH
FOR PCPN TO BE IN THE FORM OF RAIN.
&&
.AVIATION /20Z-18Z/...
CUMULUS WILL DECAY LATE THIS AFTERNOON AND EVENING. EXPECT WINDS TO
SLOWLY DECOUPLE DURING THE AFTERNOON HOURS. MIXING MID MONDAY
MORNING SHOULD ALLOW FOR 30KT WIND GUSTS UNDER SKC-FEW050 SKIES.
&&
.MARINE...
12Z ETA/GFS MOS AT THOMAS POINT INDICATE SUSTAINED WINDS WILL FALL
TO 10KT TONIGHT BEFORE RISING INTO THE 20-25KT RANGE MONDAY. 12Z
NAM/GFS PROXIMITY FORECAST SOUNDINGS INDICATE WIND GUST POTENTIAL OF
20-25KTS TONIGHT...INCREASING TO 35KTS BY LATE MONDAY AFTERNOON.
GALES TO START THE PERIOD FOR MON NIGHT. SCA CONDS MAY CONTINUE FOR
PART OF THE DAY TUES AND WILL HIGHLIGHT THIS IN THE SYNOPSIS.
&&
.FIRE WEATHER...
WITH RELATIVE HUMIDITY LEVELS FORECAST TO DROP TO 20 PERCENT...30-40
MPH WIND GUSTS...AND DRYING FUEL MOISTURE...HAVE ISSUED A FIRE
WEATHER WATCH FOR NORTH CENTRAL VIRGINIA AND LOWER SOUTHERN MARYLAND
LATE DURING MONDAY MORNING THROUGH THE AFTERNOON. FUEL MOISTURE WAS
USED TO DELINEATE THE AREA...WHILE FORECAST RELATIVE HUMIDITY LEVELS
WERE USED TO TIME THE WATCH (AS WINDS WILL PERSIST THROUGH THE
NIGHT).
&&
.HYDROLOGY...
MAIN STEM FORECAST POINTS ARE ALL UNDER FLOOD STAGE.
&&
.TIDES...
CURRENT TIDAL DEPARTURES LESS THAN A FOOT ABOVE ASTRONOMICAL
PREDICTIONS. THE LUNAR CYCLE IS AT A FULL MOON (99 PERCENT FULL).
THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM INDICATES WATER
LEVELS WILL FALL TO NEAR ASTRONOMICAL PREDICTIONS THROUGH THIS
EVENING.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...FIRE WEATHER WATCH FROM MONDAY MORNING THROUGH MONDAY
AFTERNOON FOR MDZ016>018.
VA...FIRE WEATHER WATCH FROM MONDAY MORNING THROUGH MONDAY
AFTERNOON FOR VAZ025>027-029-030-036>041-050-051-055>057.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EST MONDAY FOR ANZ530>537.
GALE WARNING FROM 3 PM MONDAY TO 6 AM EST TUESDAY FOR
ANZ530>537.
&&
$$
SHORT TERM...ROGOWSKI
LONG TERM...MANNING
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
905 AM EST SAT MAR 3 2007
.SHORT TERM...
WATER VAPOR LOOP SHOWS A POSITIVELY TILTED TROUGH ELONGATING FROM
QUEBEC SOUTHWEST THROUGH THE PLAINS. ACARS 400-250MB WIND
OBSERVATIONS REVEAL A 150-195KT SOUTHWESTERLY JET FROM THE PLAINS
THROUGH THE MID ATLANTIC. 11Z SURFACE ANALYSIS PLACED A 993MB
CYCLONE ACROSS THE UPPER GREAT LAKES. A SERIES OF COLD FRONTS EXTEND
FROM THE LOW TO THE SOUTH-SOUTHWEST. THE FIRST WAS DISSIPATING
ACROSS THE APPALACHIANS...WITH THE SECOND COLD FRONT STRETCHED
THROUGH INDIANAPOLIS AND SOUTHERN MISSOURI...AND THE THIRD WAS
ENTERING NORTHWEST ILLINOIS TO NORTHERN KANSAS.
LAPSE RATES STEEPEN THROUGHOUT THE DAY WITH THE APPROACH OF THE MID
LEVEL TROUGH. IMPULSES EMBEDDED WITHIN THE TROUGH ALOFT MAY FORCE
SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT BY MID AFTERNOON (06Z
NAM/GFS INDICATE 100-200 J/KG OF INSTABILITY DURING THE AFTERNOON).
EVAPORATIVE COOLING ASSOCIATED WITH THE INVERTED-V SOUNDING
(DOWNDRAFT TEMPERATURES NEAR 45F) SHOULD PROVIDE A FAVORABLE
ENVIRONMENT FOR HIGHER WIND GUSTS WITHIN CONVECTIVE ELEMENTS. SMALL
HAIL WILL BE POSSIBLE...ESPECIALLY ACROSS THE NORTHWEST FORECAST
AREA WHERE EQUILIBRIUM LEVEL TEMPERATURES DROP TO -25C.
MIXING THE SHALLOW (BUT STEEP) NOCTURNAL INVERSION SHOULD YIELD
60-65F ACROSS THE SOUTHEAST FORECAST AREA. KEPT THE NORTHWEST
FORECAST AREA COOLER TO ACCOUNT FOR EARLIER ARRIVAL OF CLOUDS AND
COLD ADVECTION WITH THE COLD FRONTAL PASSAGE BY LATE AFTERNOON.
SOUTHWEST WINDS WILL BE BREEZY AHEAD OF THE COLD FRONT.
&&
.HYDROLOGY...
EXPECT MAIN STEM RIVERS TO CONTINUE TO CREST...WITH ALL FORECAST
POINTS BELOW FLOOD STAGE BY LATE AFTERNOON.
&&
.AVIATION...
GRADIENT TIGHTENS AHEAD OF THE NEXT SECONDARY COLD FRONT THIS
AFTERNOON. STEEPENING LAPSE RATES MAY SUPPORT ISOLATED TO SCATTERED
SHOWER AND THUNDERSTORM ACTIVITY FROM MID AFTERNOON INTO THE EVENING.
&&
.MARINE...
00Z ETA/06 GFS MOS AT THOMAS POINT INDICATE SUSTAINED WINDS WILL
INCREASE TO NEAR 15KT THIS AFTERNOON. 06Z NAM/GFS PROXIMITY FORECAST
SOUNDINGS INDICATE WIND GUST POTENTIAL OF 25-30 KNOTS THIS AFTERNOON
AND TONIGHT.
AFTERNOON SCATTERED SHOWER AND THUNDERSTORMS MAY CONTAIN LOCALLY
HIGHER WIND GUSTS. MARINERS SHOULD MONITOR FOR LATER FORECASTS.
&&
.TIDES...
CURRENT TIDAL DEPARTURES ARE A HALF TO ONE FOOT ABOVE ASTRONOMICAL
PREDICTIONS. THE LUNAR CYCLE IS AT A FULL MOON (100 PERCENT FULL).
THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM INDICATES WATER
LEVELS WILL BE LEVEL OR GRADUALLY RECEDE CLOSER TO ASTRONOMICAL
PREDICTIONS THROUGH EARLY TONIGHT.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 12 PM SATURDAY TO 5 AM EST SUNDAY
FOR ANZ530>537.
&&
$$
SHORT TERM/HYDROLOGY/AVIATION/MARINE/TIDES...ROGOWSKI
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1055 PM EST SUN MAR 4 2007
.UPDATE...
RADAR INDICATED SCT TO NUM INTENSE SHSN SUPPORTED BY LOW LVL CONV
ALONG THE ARCTIC COLD FRONT AND THE CLIPPER SHRTWV MOVING THROUGH
THE UPPER GREAT LAKES. SNOWFALL RATES OF AN INCH IN 15 MINUTES HAS
BEEN OBSERVED WITH BANDS AS THEY MOVED THROUGH MARQUETTE AND
NEGAUNEE WITH TOTAL AMOUNTS TO 0330Z OF 2-3 INCHES. KSAW TAMDAR
SNDGS BTWN 00Z-02Z SHOWED ALSO SHOWED STRONG 850-750 MB COOLING WITH
THE INVERSION HEIGHT CLIMBING FROM 5K TO 8K FT. EVEN THOUGH 850 MB
TEMPS ARE FCST TO DROP INTO THE -20 TO -23C RANGE BY 12Z...STRONG
QVECTOR DIV WITH SUBSIDENCE/DRYING SHOULD REDUCE SHSN THE REST OF
TONIGHT AFTER THE INITIAL BURST.
WINDS HAVE ALSO BECOME VERY GUSTY WITH GUSTS TO 50 MPH AT KCMX/KP59
WITH THE PASSAGE OF THE FRONT. STRONG ISALLOBARIC COMPONENT WAS
EVIDENT WITH 8 MB/3HR PRES RISE NW OF LAKE SUPERIOR. STEEPENING
LAPSE RATES HAVE AIDED MIXING OF 40-45 KT NW WINDS (NOTED ON CYQT
TAMDAR SNDG AND VAD WND PRFL) TO THE SFC. WINDS SHOULD ALSO SUBSIDED
AFTER MIDNIGHT OVER THE KEWEENAW AS THE MAX ISALLOBARIC GRADIENT
MOVES THROUGH. THE 00Z NAM AND RUC13 SUGGEST THAT WINDS WILL PERSIST
PAST 12Z/MON INTO LOCATIONS E OF MARQUETTE. SO...GOING ADVISORIES
LOOK ON TRACK.
&&
JLB
.PREV DISCUSSION...ISSUED 450 PM EST SUN MAR 4 2007
.SHORT TERM (TNGT-MON)...
12Z RAOBS/LATEST WV IMAGERY SHOW DEEP TROF IN ERN NAMERICA DOWNWND
OF WRN RDG. POTENT SHRTWV NOTED DIGGING SE THRU NW ONTARIO TOWARD LK
SUP...AND ACCOMPANYING ARCTIC FNT APRCHG CYQT LATE THIS AFTN. NW
WIND GUSTS OVER NW ONTARIO BEHIND THE FNT HAVE ARPCHD 40 KTS AHEAD
OF AXIS OF SHARP PRES RISES THAT ARPCH 5-6MB/3HRS. EVEN AHEAD OF THE
FNT...WIND GUSTS AT EXPOSED LOCATIONS OVER THE KEWEENAW HAVE REACHED
ADVY LEVEL THIS AFTN IN THE SHARP PRES GRADIENT BTWN HI PRES TO THE
S AND THE APRCHG COLD FNT. ALTHOUGH WEBCAMS AT A NUMBER OF SITES IN
THE KEWEENAW SUG VSBY HAS NOT BEEN SGNFTLY REDUCED BY ANY BLSN...THE
CMX OB HAS INDICATED AN IFR VSBY THE LAST FEW HRS. DRY AIR TO THE NW
PER THE 12Z YPL RAOB/JUST SCT-BKN SC UPSTREAM HAS LIMITED PCPN ALONG
THE BNDRY DESPITE THE IMPRESSIVE NATURE OF THE SHRTWV THAT CAUSED
00Z-12Z H3 HGT FALLS IN EXCESS OF 100M ACRS SCNTRL CAN IN LEFT EXIT
OF ACCOMPANYING 120KT JET MAX. EXCEPT OVER THE KEWEENAW...THE DAY
OVER THE FA HAS BEEN RATHER TRANQUIL WITH DRY MID LVL AIR SHOWN ON
THE 12Z GRB SDNG DOMINATING.
MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE TIMING AND EXTENT OF
WINDS/BLSN/LES AND NEED FOR HEADLINES.
SHRTWV OVER NW ONTARIO PROGGED TO SLIDE ACRS FAR ERN LK SUP
OVERNGT...WITH JET SURGE ON ITS SW FLANK CROSSING THE FA. THIS
CLIMATOLOGICALLY FVRD TRACK FOR STRG WINDS AS WELL AS STRG WINDS
OBSERVED UPSTREAM AND CONSIDERABLE CAD THAT IS FCST TO CAUSE THE
MIXED LYR TO DEEPEN TO H7 OVER ERN LK SUP OVERNGT CERTAINLY WARRANTS
MENTION OF HI GALES TO 45 KTS ACRS THE E HALF OF THE LK...WHERE
NUMERICAL GUIDANCE SHOWS THE STRONGEST WINDS (40-45 KTS WITHIN THE
MIXED LYR) WILL OCCUR LONGER. GIVEN THESE FACTORS AND 12Z RUC13 FCST
HIEST WIND GUSTS EXCEEDING 50 KTS ACRS ERN LK SUP AS WELL AS
EVALUATION OF LOCAL HI WIND CHKLIST SHOWING UPCOMING EVENT IN THE HI
END ADVY RANGE...MENTIONED STORM FORCE WIND GUSTS ON THE E HALF
OVERNGT AS WELL. ONCE THE AXIS OF PRES RISES PASSES AFT 12Z MON...
EXPECT THE STRONGEST WINDS AND BLSN TO DIMINISH. ALTHOUGH THE DRY
AIRMASS WL GREATLY LIMIT LES ACCUMULATIONS...SUSPECT THE GUSTY WINDS
WL WHIP UP THE FLUFFY SN SUFFICIENTLY TO SGNFLY REDUCE VSBY AS AT
LEAST REPORTED ON THE CMX ASOS. SINCE THE INCOMING AIRMASS WL BE
QUITE COLD (H85 TEMPS PROGGED TO FALL AS LO AS -25C ON MON BEHIND
THE ARCTIC FNT)...SUSPECT WIND CHILLS WILL ALSO FALL SHARPLY ENUF TO
WARRANT ISSUANCE OF WINTER WX ADVY TO COVER COMBINATION OF ADVY LVL
WINDS/BLSN/FALLING SN/WIND CHILLS OVER THE KEWEENAW AND NR LK SUP AT
ALGER/LUCE COUNTIES MOST EXPOSED TO AXIS OF STRONGEST LLVL WINDS
ACRS ERN LK SUP. SINCE RUC13 INDICATES WIND GUSTS WL DCRS SHARPLY
INLAND...DID NOT EXTEND THE ADVYS FARTHER INLAND. CUT ADVY AT 06Z
OVER THE KEWEENAW TO REFLECT FASTER PASSAGE OF PRES RISE AXIS/FCST
DEPARTURE OF STRONGER LO WINDS. TIMED END OF ADVY IN ALGER/LUCE AT
15Z MON A FEW HRS AFTER PASSAGE OF AXIS OF PRES RISES.
LOOK FOR IMPROVING CONDITIONS ON MON WITH APRCH OF ARCTIC HI PRES/
WEAKENING PRES GRADIENT. BUT MAINTAINED LIKELY POPS THRU THE DAY
OVER THE ERN ZNS WITH PERSISTENCE OF COLD NW FLOW ACRS THE LK. BUT
INFUSION OF VERY DRY AIR AND VERY LO SUB INVRN TEMPS/POOR SN GROWTH
MICROPHYSICS SHOULD KEEP ACCUMS IN SUB ADVY RANGE. LOWERED FCST HI
TEMPS ON MON TO REFLECT THE STRENGTH OF THE CAD IN THE WAKE OF THE
POTENT SHRTWV AS WELL AS LO SUB INVRN TEMPS AS SHOWN ON THE GFS FCST
SDNGS.
COORDINATED WITH APX/ENVIRONMENT CAN.
KC
.LONG TERM (MON NGT-SUN)...
MON NIGHT...EXPECT SOME LINGERING LIGHT LES ALONG LAKE SUPERIOR IN
THE EVNG WITH LIGHT NRLY FLOW AHEAD OF ADVANCING SFC RDG AXIS.
COMBINATION OF LIGHT WINDS AND DEVELOPING LAND BREEZES SHOULD
ENHANCE LOW-LEVEL CONVERGENCE FOR COUNTIES E OF MQT WITH PERHAPS
LEADING TO MESOLOW FORMATION OVER ERN LAKE SUPERIOR. LOOK FOR LOCAL
ACCUMS OF AN INCH OR SO DESPITE INVERSION HGTS LOWERING AOB 4KFT PER
GFS/NAM SNDGS. ELSEWHERE...EXPECT INTERIOR SITES TO GET COLD WITH
SFC RDG MOVING OVERHEAD AND ASSOC CLEARING/LIGHT WINDS. KEPT CLOSE
TO GOING TEMP FCST WITH MUCH OF THE WRN INTERIOR LOWERING TO -5 TO
-10F.
MODELS COMING INTO BETTER AGREEMENT FOR CLIPPER SYSTEM TUE/TUE NIGHT
ALTHOUGH FOLLOWED GFS/UKMET FOR DETAILS AS THEY SEEM TO HAVE BEST
CONSISTENCY IN THE PAST FEW RUNS. GOOD 280-285K WAA/ISENTROPIC
ASCENT AND DEEP LYR Q-VECT CONV NOTED AHEAD OF CLIPPER WITH MODELS
QUICKLY SPREADING SYNOPTIC SNOW ACROSS THE FCST AREA. MODEL QPF OF
.10 TO .15 INCH WITH A 15/20-1 RATIO COULD RESULT IN 1-3" OF
ACCUMULATION MAINLY FOR TUE AFTERNOON INTO TUE EVENING. 850 MB TEMPS
OF -14 TO -18C ALONG WITH A S/SW FLOW AHEAD OF CLIPPER COULD ALSO
RESULT IN SIGNIFICANT LAKE ENHANCED SNOW OFF LAKE MI AS GFS SOUNDING
FOR NORTHERN LK MI SHOWS IMPRESSIVE DEEP FAVORABLE SNOW GROWTH LAYER
FM 900MB-600MB COINCIDING WITH OMEGA/LIFT AND MOISTURE. BLYR WIND
AND ASSOC CONVERGENCE WILL BE CRITICAL FOR DETERMINING WHERE BEST
LAKE ENHANCED SNOW WILL OCCUR. WILL LIKELY NEED A HEADLINE FOR A
LEAST ADVISORY SNOW FOR SCHOOLCRAFT COUNTY TUE AFTERNOON INTO TUE
NIGHT. THIS IS HANDLED WELL IN CURRENT HWO.
WINDS SHIFTS NRLY BEHIND CLIPPER AND ASSOC INVERTED TROF LATE TUE
NIGHT AND THEN CONTINUES INTO WED. 850 MB TEMPS OF -18 TO -20C
BEHIND TROF WILL BRING LES ACCUMS TO NORTHERN AND ERN SECTION OF
FCST AREA...ALTHOUGH DEVELOPING ANTICYCLONIC FLOW WITH ADVANCING
ARCTIC HIGH FROM CANADA AND SHARPLY LOWERING INVERSION HGTS SHOULD
KEEP ACCUMS GENERALLY LIGHT. LOWERED TEMPS DRAMATICALLY FOR INTERIOR
LOCATIONS WED NIGHT (MORE IN LINE WITH GFS MOS GUIDANCE) AS ARCTIC
HIGH COMES OVERHEAD. LOOK FOR READINGS FALLING INTO THE SINGLE
DIGITS BLO ZERO F.
EXTENDED(THU-SUN)...WAA PATTERN DEVELOPS ON BACKSIDE ON SFC HIGH
BEGINNING THU. ANTICYCLONIC FLOW AND 850 MB TEMPS RISING TO AROUND
-2 TO 0C WILL ALLOW HIGH TEMPS TO REBOUND NEAR OF ABOVE FREEZING ON
THU AFTER COLD OVERNIGHT LOWS. INCREASING WAA/ISENTROPIC WILL LEAD
TO SOME LIGHT SNOW THU NIGHT AND LIGHT MAY MIX OR CHANGE TO MORE
RAIN ON FRI AS HIGHS REACH INTO THE MID-UPPER 30S BY AFTERNOON.
MODELS STILL NOT IN GOOD AGREEMENT ON WHAT WILL HAPPEN NEXT WEEKEND.
ECMWF SHOWS WEAK COLD FRONT MOVE THROUGH FRI NIGHT WITH LITTLE IN
WAY OF CAA BEHIND IT INTO SAT. MEANWHILE...GFS AND CANADIAN MODELS
SHOW MORE PHASING OF NRN AND SRN JET STREAMS AND DEVELOP DEEPER SFC
LOW OVER LAKE HURON BY SAT WHICH PULLS IN MUCH COLDER -10C 850 MB
TEMPS BEHIND IT FOR LES DEVELOPMENT ON SAT. GIVEN UNCERTAINTY...WILL
KEEP GOING CHC POPS FOR SNOW SAT WITH DRY CONDITIONS SAT NIGHT INTO
SUN.
COORDINATED WITH APX/GRB/DLH.
JV
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY MIZ001-003 TIL 06Z MON.
WINTER WEATHER ADVISORY MIZ006-007 00Z-15Z MON.
GALE WARNING LAKE SUPERIOR.
HEAVY FREEZING SPRAY WARNING EAST HALF LAKE SUPERIOR.
&&
$$
KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1015 AM EST SAT MAR 3 2007
.UPDATE...
12Z RAOBS/WV IMAGERY AND RUC ANALYSIS SHOW WEAKENING OCCLUSION OVER
NRN LK HURON SLIPPING SLOWLY TO THE E WITH CONSIDERABLE 00Z-12Z H5
HGT RISES NOTED TO THE W (110M AT MPX) IN THE WAKE OF THIS MAJOR
WINTER STORM. AS A RESULT...MUCH DRIER MID LVL AIR/LOWER INVRN HGT
JUST BLO H9 AS SHOWN ON THE 12Z INL/YPL RAOBS IS BEGINNING TO
ADVANCE INTO WRN LK SUP AND THE FAR WRN CWA. VSBY AT IWD HAS RISEN
QUICKLY THIS MRNG WITH APRNT ARRIVAL OF THE LOWER INVRN. WIND SPEEDS
BEGINNING TO DCRS OVER WRN LK SUP AS WELL WITH DCRS IN MIXING DEPTH
EVEN THOUGH PRES GRADIENT REMAINS RATHER SHARP. FARTHER E...HEAVIER
SHSN CONT OVER THE NCNTRL WHERE AXIS OF DEEPER MSTR APRNT ON STLT
IMAGERY ENHANCING LES IN CYC N FLOW. 12Z GRB SDNG INDICATES DEEP
MSTR EXTENDS TO H3 WITHIN THIS AXIS OF DEEPER MSTR.
MAIN FCST CONCERNS IN THE SHORT TERM REVOLVE ARND LES TRENDS/AMTS/
WINDS/GOING HEADLINES.
LATEST RUC IS SLOWER AT MOVING DEEPER MSTR TO THE E THAN THE LATEST
NAM BECAUSE THAT MODEL SHOWS A REINFORCING SHRTWV OVER NW ONTARIO
DROPPING S (REFLECTED IN 20M 00Z-12Z H HGT FALL AT YPL) ON THE BACK
SIDE OF PARENT OCCLUDED LO AND MAINTAINING HIER MID LVL MSTR/
SUBSIDENCE INVRN BASE. HOWEVER...RUC SHOWS LARGER SCALE DEEP LYR
QVECTOR DVGC/SUBSIDENCE...INDICATING THAT DRY ADVCTN WL OVERCOME THE
PVA. FAVOR FASTER NAM PER STLT/OBSVD TRENDS. ALL IN ALL...GOING FCST
HAS OBSVD/EXPECTED TRENDS IN HAND. MAINTAINED HEADLINE ENDING TIMES
BY EARLY AFTN OVER THE W AND EARLY EVNG IN MQT/ALGER COUNTIES. MINOR
CHGS MADE INCLUDE INCRSG COVG OF SHSN OVER NRN DELTA COUNTY/A BIT
MORE SN INTO EARLY AFTN TO ACCOUNT FOR LATEST RADAR IMAGERY SHOWING
HEAVIER BANDS MOVING INTO THE NRN PART OF THAT COUNTY. ALSO TENDED
TO DIMINISH WINDS FASTER OVER THE W HALF OF LK SUP WITH ARRIVAL OF
LOWER INVRN/REDUCED MIXING DEPTH.
KC
.PREVIOUS DISCUSSION (ISSUED AT 435 AM)...
MAIN FCST ISSUES ARE FATE OF ONGOING HEADLINES AND TIMING THE END OF
SNOW AS DECAYING STORM SYSTEM OVER THE GREAT LAKES HEADS E.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW MIDLEVEL LOW CONTINUING TO
FILL AS IT TRACKS E ACROSS NRN LWR MI EARLY THIS MORNING. MOISTURE
WRAPPING AROUND THE SYSTEM STILL ENCOMPASSES UPPER MI/LAKE SUPERIOR.
DEEP MOISTURE/CYCLONIC FLOW COMBINED WITH 850MB TEMPS RANGING FROM
ABOUT -14C SCNTRL LAKE SUPERIOR TO -16C WRN LAKE SUPERIOR PER 06Z
RUC ANALYSIS IS RESULTING IN LAKE ENHANCED SNOW IN N WIND FAVORED
LOCATIONS. 850MB TEMPS ARE PROBABLY LOWER THAN RUC ANALYSIS OVER THE
W AS 05Z TAMDAR SOUNDING FROM CYQT SHOWED 850MB TEMP OF -19C. IT
ALSO APPEARS 850MB TEMPS HAVE DROPPED A BIT MORE RECENTLY OVER CNTRL
LAKE SUPERIOR AS LES BANDS ARE BEGINNING TO FORM IN WHAT HAD BEEN AN
AREA OF SNOW WITH LITTLE STRUCTURE/ORGANIZATION. KDLH RADAR HAS
OCCASIONALLY SHOWED BANDS STREAMING INTO FAR WRN UPPER MI NEAR
KIWD...SO DECENT SNOW HAS BEEN OCCURRING IN THAT AREA OVERNIGHT. HAD
A REPORT JUST AFTER MIDNIGHT OF MDT TO HVY SNOW ON THE KEWEENAW IN
THE PHOENIX/DELAWARE AREAS. SNOW OVERNIGHT HAS HAD A HIGH SNOW TO
WATER RATIO AS EXPECTED DUE TO 7-10KFT LAYER OF FAVORABLE DENDRITIC
SNOW GROWTH TEMPS IN THE MOIST LAYER.
MODELS ARE IN GOOD AGREEMENT TAKING MIDLEVEL LOW TO SRN QUEBEC BY
00Z SUN...AND NAM/GFS ARE NOW ALSO IN GOOD AGREEMENT BRINGING BACK
EDGE OF DEEP MOISTURE W TO E ACROSS THE FCST AREA TODAY/TONIGHT. IT
SHOULD REACH THE WRN FCST AREA LATE MORNING/EARLY AFTN AND CLEAR THE
FAR ERN FCST AREA MID/LATE EVENING. AT THE SAME TIME...CYCLONIC FLOW
WILL RELAX AND BECOME NEUTRAL THEN ANTICYCLONIC FROM W TO E. EVEN
THOUGH 850MB TEMPS WILL RANGE FROM -13C TO -16C TO SUPPORT LES THRU
THE DAY...DEPARTURE OF DEEP MOISTURE WILL RESULT IN A SHARP
DIMINISHING TREND BEFORE SHSN END W THIS EVENING AND E LATE
TONIGHT. WITH EXPECTED FLUFFY ACCUMULATIONS OF 1 TO 3 INCHES W AND 1
TO 4 INCHES NCNTRL TODAY...WILL NEED TO EXTEND HEADLINES EVEN THOUGH
A FEW INCHES OF THIS LOW WATER CONTENT SNOW WILL REALLY NOT BE MUCH
MORE THAN A NUISANCE COMPARED TO WHAT THE AREA EXPERIENCED THU
NIGHT/FRI.
PERIOD OF MOSTLY CLEAR/PARTLY CLOUDY SKIES WILL FOLLOW FROM W TO E
TONIGHT/SUN MORNING. RIBBON OF ISENTROPIC ASCENT (290K SFC)
ASSOCIATED WITH A WEAK SHORTWAVE DIVING SE TOWARD THE UPPER LAKES
WILL PASS ACROSS THE AREA LATE TONIGHT THRU EARLY SUN AFTN. EVEN
SO...IT LOOKS LIKE A GOOD PORTION OF THE NIGHT WILL BE MOSTLY
CLEAR/PARTLY CLOUDY OVER ROUGHLY THE W HALF OF FCST AREA. THIS
SHOULD ALLOW FOR DECENT RADIATIONAL COOLING AS WEAK SFC RIDGE
PASSES. HAVE THUS FAVORED THE LOWER SIDE OF MOS GUIDANCE OVER THE
INTERIOR W. CLOUDS WILL LINGER THRU MOST IF NOT ALL OF THE NIGHT
OVER THE FAR E...KEEPING MINS HIGHER THERE THAN OVER THE W.
RIBBON OF MID/HIGH CLOUDS WILL PROGRESS ACROSS THE AREA SUN...AND IT
APPEARS TO BE FOLLOWED BY A LOWER STRATOCU DECK PER GFS/NAM RH
PROGS. LOW-LEVEL ISENTROPIC ASCENT WITH LOW CONDENSATION PRES
DEFICITS ON THE 275K SFC (ROUGHLY AROUND 900MB) SUPPORTS THE IDEA OF
SCT/BKN LOWER CLOUDS SWEEPING INTO THE AREA SUN AFTN/EVENING. THESE
CLOUDS WILL BE AHEAD OF A STRONGER SHORTWAVE HEADING SE INTO
ONTARIO. PRES GRADIENT TIGHTENS AHEAD OF FEATURE WITH NAM/GFS
SHOWING WRLY 950MB WINDS RAMPING UP TO 35 TO 40KT SUN AFTN/EVENING
AHEAD OF APPROACHING ARCTIC FRONT...SUPPORTING POTENTIAL OF GALES ON
LAKE SUPERIOR. REGARDING SHORTWAVE...NAM IS QUITE A BIT STRONGER
WITH FEATURE THAN GFS/UKMET/CANADIAN...AND IT IS ABOUT 6 HRS SLOWER
WITH FROPA. SEE NO REASON NOT TO FOLLOW BULK OF GUIDANCE WITH REGARD
TO DETAILS. WRLY GALES AHEAD OF FRONT WILL SHIFT TO A PERIOD OF NW
GALES AFTER FROPA SUN NIGHT UNDER STRONG CAA REGIME (850MB TEMPS
FALL FROM AROUND -10C SUN EVENING TO AROUND -20C BY MON MORNING).
WITH 850MB TEMPS TOO HIGH TO SUPPORT LES PRIOR TO FROPA...NOT REALLY
EXPECTING A SIGNIFICANT BAND OF SNOW ALONG ARCTIC FRONT AS IT
PASSES. IN ADDITION...BULK OF FORCING WITH SHORTWAVE PASSES NE OF
FCST AREA. AT THIS POINT...CHC POPS LOOK FINE WITH FROPA SUN NIGHT.
HEALTHY SUBSIDENCE/DRY AIR AND INVERSION SETTLING TO AROUND 4KFT ON
MON SUGGEST LES WILL BE ON THE LIGHT SIDE DESPITE 850MB TEMPS IN THE
-20 TO -23C RANGE.
ARCTIC HIGH PRES RIDGE BUILDS SE OVER THE UPPER LAKES/ONTARIO MON
NIGHT...SETTING UP WHAT WOULD APPEAR TO BE A VERY COLD NIGHT OVER
THE INTERIOR W AND CNTRL FCST AREA. HOWEVER...MODELS ARE FAIRLY
AGGRESSIVE IN SPREADING CONSIDERABLE MID/HIGH LEVEL MOISTURE INTO
THE AREA DOWNSTREAM OF DEVELOPING WAA PATTERN OVER THE NRN
PLAINS/UPPER MISSISSIPPI VALLEY. NOT SURE HOW LONG THE WINDOW WILL
BE FOR RADIATIONAL COOLING...BUT WILL TAKE A CONSERVATIVE APPROACH
ON TEMP DROP MON NIGHT...GOING A FEW DEGREES ABOVE LATEST GFS MOS
GUIDANCE. SHOULD BULK OF NIGHT END UP CLEAR...TEMPS WOULD LIKELY
FALL TO -15F IN THE TYPICAL COLD SPOTS.
BEYOND MON NIGHT...REST OF NEXT WEEK SHOWS PLENTY OF UNCERTAINTY
WITH A SERIES OF SHORTWAVES RUNNING ALONG BOUNDARY BTWN ARCTIC AIR
IN CANADA AND MILD AIR COVERING MUCH OF THE CNTRL CONUS. FIRST OF
THESE WILL ARRIVE TUE...AND GOING FCST HAS THIS COVERED WELL WITH
-SN CHC POPS. NO CHANGES NEEDED BEYOND TUE.
ROLFSON
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 18Z TODAY MIZ002-004-009.
WINTER STORM WARNING UNTIL 23Z TODAY MIZ005.
SNOW AND BLOWING SNOW ADVY UNTIL 18Z TODAY MIZ001-003.
SNOW AND BLOWING SNOW ADVY UNTIL 23Z TODAY MIZ006.
GALE WARNING LAKE SUPERIOR.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
435 AM EST SAT MAR 3 2007
.DISCUSSION...
MAIN FCST ISSUES ARE FATE OF ONGOING HEADLINES AND TIMING THE END OF
SNOW AS DECAYING STORM SYSTEM OVER THE GREAT LAKES HEADS E.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW MIDLEVEL LOW CONTINUING TO
FILL AS IT TRACKS E ACROSS NRN LWR MI EARLY THIS MORNING. MOISTURE
WRAPPING AROUND THE SYSTEM STILL ENCOMPASSES UPPER MI/LAKE SUPERIOR.
DEEP MOISTURE/CYCLONIC FLOW COMBINED WITH 850MB TEMPS RANGING FROM
ABOUT -14C SCNTRL LAKE SUPERIOR TO -16C WRN LAKE SUPERIOR PER 06Z
RUC ANALYSIS IS RESULTING IN LAKE ENHANCED SNOW IN N WIND FAVORED
LOCATIONS. 850MB TEMPS ARE PROBABLY LOWER THAN RUC ANALYSIS OVER THE
W AS 05Z TAMDAR SOUNDING FROM CYQT SHOWED 850MB TEMP OF -19C. IT
ALSO APPEARS 850MB TEMPS HAVE DROPPED A BIT MORE RECENTLY OVER CNTRL
LAKE SUPERIOR AS LES BANDS ARE BEGINNING TO FORM IN WHAT HAD BEEN AN
AREA OF SNOW WITH LITTLE STRUCTURE/ORGANIZATION. KDLH RADAR HAS
OCCASIONALLY SHOWED BANDS STREAMING INTO FAR WRN UPPER MI NEAR
KIWD...SO DECENT SNOW HAS BEEN OCCURRING IN THAT AREA OVERNIGHT. HAD
A REPORT JUST AFTER MIDNIGHT OF MDT TO HVY SNOW ON THE KEWEENAW IN
THE PHOENIX/DELAWARE AREAS. SNOW OVERNIGHT HAS HAD A HIGH SNOW TO
WATER RATIO AS EXPECTED DUE TO 7-10KFT LAYER OF FAVORABLE DENDRITIC
SNOW GROWTH TEMPS IN THE MOIST LAYER.
MODELS ARE IN GOOD AGREEMENT TAKING MIDLEVEL LOW TO SRN QUEBEC BY
00Z SUN...AND NAM/GFS ARE NOW ALSO IN GOOD AGREEMENT BRINGING BACK
EDGE OF DEEP MOISTURE W TO E ACROSS THE FCST AREA TODAY/TONIGHT. IT
SHOULD REACH THE WRN FCST AREA LATE MORNING/EARLY AFTN AND CLEAR THE
FAR ERN FCST AREA MID/LATE EVENING. AT THE SAME TIME...CYCLONIC FLOW
WILL RELAX AND BECOME NEUTRAL THEN ANTICYCLONIC FROM W TO E. EVEN
THOUGH 850MB TEMPS WILL RANGE FROM -13C TO -16C TO SUPPORT LES THRU
THE DAY...DEPARTURE OF DEEP MOISTURE WILL RESULT IN A SHARP
DIMINISHING TREND BEFORE SHSN END W THIS EVENING AND E LATE
TONIGHT. WITH EXPECTED FLUFFY ACCUMULATIONS OF 1 TO 3 INCHES W AND 1
TO 4 INCHES NCNTRL TODAY...WILL NEED TO EXTEND HEADLINES EVEN THOUGH
A FEW INCHES OF THIS LOW WATER CONTENT SNOW WILL REALLY NOT BE MUCH
MORE THAN A NUISANCE COMPARED TO WHAT THE AREA EXPERIENCED THU
NIGHT/FRI.
PERIOD OF MOSTLY CLEAR/PARTLY CLOUDY SKIES WILL FOLLOW FROM W TO E
TONIGHT/SUN MORNING. RIBBON OF ISENTROPIC ASCENT (290K SFC)
ASSOCIATED WITH A WEAK SHORTWAVE DIVING SE TOWARD THE UPPER LAKES
WILL PASS ACROSS THE AREA LATE TONIGHT THRU EARLY SUN AFTN. EVEN
SO...IT LOOKS LIKE A GOOD PORTION OF THE NIGHT WILL BE MOSTLY
CLEAR/PARTLY CLOUDY OVER ROUGHLY THE W HALF OF FCST AREA. THIS
SHOULD ALLOW FOR DECENT RADIATIONAL COOLING AS WEAK SFC RIDGE
PASSES. HAVE THUS FAVORED THE LOWER SIDE OF MOS GUIDANCE OVER THE
INTERIOR W. CLOUDS WILL LINGER THRU MOST IF NOT ALL OF THE NIGHT
OVER THE FAR E...KEEPING MINS HIGHER THERE THAN OVER THE W.
RIBBON OF MID/HIGH CLOUDS WILL PROGRESS ACROSS THE AREA SUN...AND IT
APPEARS TO BE FOLLOWED BY A LOWER STRATOCU DECK PER GFS/NAM RH
PROGS. LOW-LEVEL ISENTROPIC ASCENT WITH LOW CONDENSATION PRES
DEFICITS ON THE 275K SFC (ROUGHLY AROUND 900MB) SUPPORTS THE IDEA OF
SCT/BKN LOWER CLOUDS SWEEPING INTO THE AREA SUN AFTN/EVENING. THESE
CLOUDS WILL BE AHEAD OF A STRONGER SHORTWAVE HEADING SE INTO
ONTARIO. PRES GRADIENT TIGHTENS AHEAD OF FEATURE WITH NAM/GFS
SHOWING WRLY 950MB WINDS RAMPING UP TO 35 TO 40KT SUN AFTN/EVENING
AHEAD OF APPROACHING ARCTIC FRONT...SUPPORTING POTENTIAL OF GALES ON
LAKE SUPERIOR. REGARDING SHORTWAVE...NAM IS QUITE A BIT STRONGER
WITH FEATURE THAN GFS/UKMET/CANADIAN...AND IT IS ABOUT 6 HRS SLOWER
WITH FROPA. SEE NO REASON NOT TO FOLLOW BULK OF GUIDANCE WITH REGARD
TO DETAILS. WRLY GALES AHEAD OF FRONT WILL SHIFT TO A PERIOD OF NW
GALES AFTER FROPA SUN NIGHT UNDER STRONG CAA REGIME (850MB TEMPS
FALL FROM AROUND -10C SUN EVENING TO AROUND -20C BY MON MORNING).
WITH 850MB TEMPS TOO HIGH TO SUPPORT LES PRIOR TO FROPA...NOT REALLY
EXPECTING A SIGNIFICANT BAND OF SNOW ALONG ARCTIC FRONT AS IT
PASSES. IN ADDITION...BULK OF FORCING WITH SHORTWAVE PASSES NE OF
FCST AREA. AT THIS POINT...CHC POPS LOOK FINE WITH FROPA SUN NIGHT.
HEALTHY SUBSIDENCE/DRY AIR AND INVERSION SETTLING TO AROUND 4KFT ON
MON SUGGEST LES WILL BE ON THE LIGHT SIDE DESPITE 850MB TEMPS IN THE
-20 TO -23C RANGE.
ARCTIC HIGH PRES RIDGE BUILDS SE OVER THE UPPER LAKES/ONTARIO MON
NIGHT...SETTING UP WHAT WOULD APPEAR TO BE A VERY COLD NIGHT OVER
THE INTERIOR W AND CNTRL FCST AREA. HOWEVER...MODELS ARE FAIRLY
AGGRESSIVE IN SPREADING CONSIDERABLE MID/HIGH LEVEL MOISTURE INTO
THE AREA DOWNSTREAM OF DEVELOPING WAA PATTERN OVER THE NRN
PLAINS/UPPER MISSISSIPPI VALLEY. NOT SURE HOW LONG THE WINDOW WILL
BE FOR RADIATIONAL COOLING...BUT WILL TAKE A CONSERVATIVE APPROACH
ON TEMP DROP MON NIGHT...GOING A FEW DEGREES ABOVE LATEST GFS MOS
GUIDANCE. SHOULD BULK OF NIGHT END UP CLEAR...TEMPS WOULD LIKELY
FALL TO -15F IN THE TYPICAL COLD SPOTS.
BEYOND MON NIGHT...REST OF NEXT WEEK SHOWS PLENTY OF UNCERTAINTY
WITH A SERIES OF SHORTWAVES RUNNING ALONG BOUNDARY BTWN ARCTIC AIR
IN CANADA AND MILD AIR COVERING MUCH OF THE CNTRL CONUS. FIRST OF
THESE WILL ARRIVE TUE...AND GOING FCST HAS THIS COVERED WELL WITH
-SN CHC POPS. NO CHANGES NEEDED BEYOND TUE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 18Z TODAY MIZ002-004-009.
WINTER STORM WARNING UNTIL 23Z TODAY MIZ005.
SNOW AND BLOWING SNOW ADVY UNTIL 18Z TODAY MIZ001-003.
SNOW AND BLOWING SNOW ADVY UNTIL 23Z TODAY MIZ006.
GALE WARNING LAKE SUPERIOR.
&&
$$
ROLFSON
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
927 PM EST SUN MAR 4 2007
.UPDATE...
&&
.SHORT TERM /REST OF TONIGHT INTO MONDAY/...
STILL A FFW CLOUDS FROM GREENBRIER NORTHWARD...ELSE CLEAR SKIES
ENTIRE CWA. WILL UPDATE ZFP TO GET RID OF EVENING WORDING.
WILL ALSO GO WITH...CLEAR...FOR THE PREDOMINATE SKY FCST
OVERNIGHT.
WINDS WILL REMAIN A BIT BRISK OVERNIGHT...ESP HIGHER TERRAIN. WIND
WILL BECOME A FIRE WEATHER CONCERN MONDAY AS RH DIPS DURING THE AFTN.
CONCERN IS EAST OF BLUE RIDGE WHERE GRASSES AND LEAF LITTER ARE
DRYER. MAIN THREAT WILL BE DURING THE AFTERNOON WHEN SFC TEMPS ARE
THE WARMEST AND RH THE DRYEST.
&&
.PREV DISCUSSION...
/ISSUED 623 PM EST SUN MAR 4 2007/
UPDATE...
AVIATION /00Z-24Z/...
HIGH PRESSURE WILL BE MOVING INTO THE REGION FROM THE NORTHWEST
THROUGH THE PERIOD BUT A PRESSURE GRADIENT WILL REMAIN.
WINDS ARE EXPECTED TO INCREASE AGAIN TONIGHT AS PRESSURE RISES AND
LOW LEVEL JET INTENSIFIES AFTER 06Z MON. THIS LOW LEVEL JET IS
EXPECTED TO STRENGTHEN TO 50-60 KTS ACROSS THE AREA BETWEEN 09Z AND
18Z MON. NAM DEPICTING A 60-70 KT LOW LEVEL JET NORTH OF THE AREA
FROM KHSP TO KCBE DURING THIS TIME AS WELL. AIRCRAFT TRAVELING TO OR
ALONG THE APPALACHIAN MOUNTAINS SHOULD BE PREPARED FOR TURBULENCE
AND WIND SHEAR INTO MONDAY AFTERNOON.
THERE STILL MAY BE A FEW LIGHT SNOW SHOWERS FALLING ALONG WESTERN
SLOPES THROUGH THIS EVENING. ANY MVFR CEILING THIS EVENING WILL
LIKELY BE ALONG WESTERN SLOPES ACROSS SE WV. AFTER 06Z
MON...CEILING ARE EXPECTED TO REBOUND TO VFR.
PREV DISCUSSION...
/ISSUED 240 PM EST SUN MAR 4 2007/
SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
MORE SHORTWAVE ENERGY WILL BE DROPPING DOWN THRU THE AREA WITHIN THE
LONGER WAVE TROF WHICH WILL REMAIN ANCHORED OVER THE EASTERN U.S.
THROUGH MIDWEEK. THIS WILL BASICALLY KEEP PERIODS OF COLD AIR
ADVECTION AND BREEZY OR WINDY CONDITIONS GOING THRU THURSDAY MORNING
MORNING.
THE FIRST OF THE TWO MAIN WAVES DROPPING INTO THE TROF OVER THE NEXT
FEW DAYS WILL DO SO MONDAY OVER THE UPPER MID-ATLANTIC...BRINGING A
MODEST INCREASE IN LOW LEVEL MOISTR TO THE NORTHWEST BY MONDAY
AFTERNOON AND EVENING. RIGHT NOW THINKING THAT IT WILL BE MAINLY
FLURRIES. HEIGHTS RISE A LITTLE TUESDAY THEN A
STRONGER...CLIPPER...WAVE DROPS DOWN INTO THE TROF WED AND PASSES
THRU THE LOWER MID-ATLANTIC. THIS MAY BRING A BETTER CHANCE OF
PCPN...LIKELY MIXED PCPN...TO THE NORTH AND COULD SPREAD IT EAST
OF THE MOUNTAINS ACROSS CENTRAL VA BEFORE A BRIEF COLD SHOT AND
UPSLOPE SNOW SHOWERS WEDNESDAY NIGHT.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
APPEARS FOR NOW THAT THURSDAY AND FRIDAY WILL REMAIN DRY AS HEIGHTS
BUILD AGAIN AND STRONG SFC RIDGE TRACKS ACROSS NEW ENGLAND AND
NOSES DOWN THE EAST COAST. THERE IS QUITE A DIFFERENCE IN THE
MODELS CONCERNING TEMPERATURES FOR THE PERIOD AS THE ECMWF AND
CANADIAN MODELS KEEP COLD AIR BOTTLED UP ACROSS THE GREAT LAKES
FOLLOWING THE PASSAGE OF WEDNESDAYS CLIPPER THRU THE OHIO VALLEY.
THE GFS ADVECTS MORE COLD AIR INTO THE REGION. IF THE GFS IS WRONG
THIS COULD BE QUITE A WARM UP FOR LATE IN THE WEEK.
ON FRIDAY ONSHORE FLOW BEGINS DEVELOPING AS THE SFC RIDGE MOVES OFF
THE COAST...LEADING TO AN INCREASE IN CLOUDINESS AND A CHANCE OF
UPSLOPE RAIN AND DRIZZLE FRIDAY NIGHT AHEAD OF THE NEXT FRONT.
LONG RANGE MODELS ARE IN DECENT AGREEMENT ON BRINGING PACIFIC ENERGY
.ALONG WITH A COLD FRONT...ACROSS THE COUNTRY AND INTO THE EASTERN
U.S. BY NEXT SATURDAY OR SUNDAY. TIMING OF COURSE IS THE MAIN ISSUE
FOR NOW. THE AIRMASS BEHIND THIS FRONT DOES NOT APPEAR TO BE
SIGNIFICANTLY COLD THANKS TO ITS PACIFIC ORIGIN.
AVIATION /20Z-18Z/...
BUFKIT DATA HAS SNOW SHOWERS ENDING AT BLF AND LWB BETWEEN 21 AND
00Z WHICH IS SUPPORTED BY RADAR TRENDS. MVFR CEILINGS WILL
DISSIPATE AROUND 03Z AT BLF AND LWB. WINDS WILL DECOUPLE IN THE
VALLEYS WITH LOW LEVEL WIND SHEAR OVERNIGHT AT DAN...LYH...AND
LWB. DEEP MIXING IS EXPECTED AGAIN ON MONDAY LEADING TO GUSTY
WINDS AFT 14Z.
FIRE WEATHER...
ISSUING A FIRE WEATHER WATCH FOR MONDAY AFTN DUE TO THE RAPID
DRYING OF THE PAST COUPLE DAYS...CONTINUED STIFF WINDS AND
HUMIDITIES DURING THE AFTN TMRW APPROACHING MINIMUMS IN THE UPPER
TEENS AND LOWER 20S. THE LIMITING FACTOR MAY BE THE WINDS...AS
VALUES MAY FALL SHORT OF THE 15 TO 20 MPH THRESHOLD FOR SUSTAINED
WINDS. HOWEVER OVERALL FIRE DANGER REMAINS IN THE VERY HIGH TO
EXTREME CATEGORY OVER MUCH OF THE AREA.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FIRE WEATHER WATCH FROM MONDAY MORNING THROUGH MONDAY
AFTERNOON FOR VAZ022>024-032>035-043>047-058-059.
NC...FIRE WEATHER WATCH FROM MONDAY MORNING THROUGH MONDAY
AFTERNOON FOR NCZ003>006-019-020.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
623 PM EST SUN MAR 4 2007
.UPDATE...
&&
.AVIATION /00Z-24Z/...
HIGH PRESSURE WILL BE MOVING INTO THE REGION FROM THE NORTHWEST
THROUGH THE PERIOD BUT A PRESSURE GRADIENT WILL REMAIN.
WINDS ARE EXPECTED TO INCREASE AGAIN TONIGHT AS PRESSURE RISES AND
LOW LEVEL JET INTENSIFIES AFTER 06Z MON. THIS LOW LEVEL JET IS
EXPECTED TO STRENGTHEN TO 50-60 KTS ACROSS THE AREA BETWEEN 09Z AND
18Z MON. NAM DEPICTING A 60-70 KT LOW LEVEL JET NORTH OF THE AREA
FROM KHSP TO KCBE DURING THIS TIME AS WELL. AIRCRAFT TRAVELING TO OR
ALONG THE APPALACHIAN MOUNTAINS SHOULD BE PREPARED FOR TURBULENCE
AND WIND SHEAR INTO MONDAY AFTERNOON.
THERE STILL MAY BE A FEW LIGHT SNOW SHOWERS FALLING ALONG WESTERN
SLOPES THROUGH THIS EVENING. ANY MVFR CEILING THIS EVENING WILL
LIKELY BE ALONG WESTERN SLOPES ACROSS SE WV. AFTER 06Z
MON...CEILING ARE EXPECTED TO REBOUND TO VFR.
&&
.PREV DISCUSSION...
/ISSUED 240 PM EST SUN MAR 4 2007/
SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
MORE SHORTWAVE ENERGY WILL BE DROPPING DOWN THRU THE AREA WITHIN THE
LONGER WAVE TROF WHICH WILL REMAIN ANCHORED OVER THE EASTERN U.S.
THROUGH MIDWEEK. THIS WILL BASICALLY KEEP PERIODS OF COLD AIR
ADVECTION AND BREEZY OR WINDY CONDITIONS GOING THRU THURSDAY MORNING
MORNING.
THE FIRST OF THE TWO MAIN WAVES DROPPING INTO THE TROF OVER THE NEXT
FEW DAYS WILL DO SO MONDAY OVER THE UPPER MID-ATLANTIC...BRINGING A
MODEST INCREASE IN LOW LEVEL MOISTR TO THE NORTHWEST BY MONDAY
AFTERNOON AND EVENING. RIGHT NOW THINKING THAT IT WILL BE MAINLY
FLURRIES. HEIGHTS RISE A LITTLE TUESDAY THEN A
STRONGER...CLIPPER...WAVE DROPS DOWN INTO THE TROF WED AND PASSES
THRU THE LOWER MID-ATLANTIC. THIS MAY BRING A BETTER CHANCE OF
PCPN...LIKELY MIXED PCPN...TO THE NORTH AND COULD SPREAD IT EAST
OF THE MOUNTAINS ACROSS CENTRAL VA BEFORE A BRIEF COLD SHOT AND
UPSLOPE SNOW SHOWERS WEDNESDAY NIGHT.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
APPEARS FOR NOW THAT THURSDAY AND FRIDAY WILL REMAIN DRY AS HEIGHTS
BUILD AGAIN AND STRONG SFC RIDGE TRACKS ACROSS NEW ENGLAND AND
NOSES DOWN THE EAST COAST. THERE IS QUITE A DIFFERENCE IN THE
MODELS CONCERNING TEMPERATURES FOR THE PERIOD AS THE ECMWF AND
CANADIAN MODELS KEEP COLD AIR BOTTLED UP ACROSS THE GREAT LAKES
FOLLOWING THE PASSAGE OF WEDNESDAYS CLIPPER THRU THE OHIO VALLEY.
THE GFS ADVECTS MORE COLD AIR INTO THE REGION. IF THE GFS IS WRONG
THIS COULD BE QUITE A WARM UP FOR LATE IN THE WEEK.
ON FRIDAY ONSHORE FLOW BEGINS DEVELOPING AS THE SFC RIDGE MOVES OFF
THE COAST...LEADING TO AN INCREASE IN CLOUDINESS AND A CHANCE OF
UPSLOPE RAIN AND DRIZZLE FRIDAY NIGHT AHEAD OF THE NEXT FRONT.
LONG RANGE MODELS ARE IN DECENT AGREEMENT ON BRINGING PACIFIC ENERGY
..ALONG WITH A COLD FRONT...ACROSS THE COUNTRY AND INTO THE EASTERN
U.S. BY NEXT SATURDAY OR SUNDAY. TIMING OF COURSE IS THE MAIN ISSUE
FOR NOW. THE AIRMASS BEHIND THIS FRONT DOES NOT APPEAR TO BE
SIGNIFICANTLY COLD THANKS TO ITS PACIFIC ORIGIN.
AVIATION /20Z-18Z/...
BUFKIT DATA HAS SNOW SHOWERS ENDING AT BLF AND LWB BETWEEN 21 AND
00Z WHICH IS SUPPORTED BY RADAR TRENDS. MVFR CEILINGS WILL
DISSIPATE AROUND 03Z AT BLF AND LWB. WINDS WILL DECOUPLE IN THE
VALLEYS WITH LOW LEVEL WIND SHEAR OVERNIGHT AT DAN...LYH...AND
LWB. DEEP MIXING IS EXPECTED AGAIN ON MONDAY LEADING TO GUSTY
WINDS AFT 14Z.
FIRE WEATHER...
ISSUING A FIRE WEATHER WATCH FOR MONDAY AFTN DUE TO THE RAPID
DRYING OF THE PAST COUPLE DAYS...CONTINUED STIFF WINDS AND
HUMIDITIES DURING THE AFTN TMRW APPROACHING MINIMUMS IN THE UPPER
TEENS AND LOWER 20S. THE LIMITING FACTOR MAY BE THE WINDS...AS
VALUES MAY FALL SHORT OF THE 15 TO 20 MPH THRESHOLD FOR SUSTAINED
WINDS. HOWEVER OVERALL FIRE DANGER REMAINS IN THE VERY HIGH TO
EXTREME CATEGORY OVER MUCH OF THE AREA.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FIRE WEATHER WATCH FROM MONDAY MORNING THROUGH MONDAY
AFTERNOON FOR VAZ022>024-032>035-043>047-058-059.
NC...FIRE WEATHER WATCH FROM MONDAY MORNING THROUGH MONDAY
AFTERNOON FOR NCZ003>006-019-020.
WV...NONE.
&&
$$
UPDATE...
AVIATION...RCS
AREA FORECAST DISCUSSION
NWS SEATTLE WA
245 AM PST SAT MAR 3 2007
.SYNOPSIS...LIGHT RAIN WILL BEGIN DECREASING THIS MORNING AS A WEAK
FRONT MOVES EAST OF THE AREA. A WEAK UPPER LEVEL RIDGE WILL PRODUCE
MOSTLY DRY BUT CLOUDY WEATHER TONIGHT. THE RIDGE WILL MOVE EAST
TONIGHT AND INCREASING SOUTHWEST FLOW ALOFT WILL ALLOW A SERIES OF
WEATHER SYSTEMS TO REACH THE REGION THROUGH LATE NEXT WEEK. A STRONG
COLD FRONT WILL APPROACH THE AREA MONDAY NIGHT AND MOVE THROUGH LATE
TUESDAY.
&&
.SHORT TERM...A WEAK WARM FRONT IS SOMEWHERE OVER THE AREA THIS
MORNING BUT NO REAL SURFACE BOUNDARY IS EVIDENT ON SATELLITE OR IN
OBS. MOST SIGNIFICANT POINT IS THAT THE VERY MOIST AIR MASS WILL
CONTINUE OVER THE AREA TODAY...WITH UPWARD MOTION ENDING THIS
MORNING AS WHATEVER IS LEFT OF THE WARM FRONT DISSIPATES OR MOVES
EAST. THUS KEPT THE LIKELY POPS FOR THIS MORNING...A LITTLE HIGHER
THAN MOS GUIDANCE AND STAYED WITH CHANCE POPS THIS AFTERNOON.
SURFACE GRADIENTS WILL ALSO WEAKEN TODAY SO WE`RE STUCK WITH THE LOW
LEVEL MOISTURE TONIGHT. ANY LOSS IN CLOUD COVER OVERNIGHT WILL HELP
FOG FORM.
CASCADES...ACARS SOUNDINGS AROUND MIDNIGHT SHOWED A FREEZING LEVEL
6500-7000 FEET...BUT OBS SHOW THE PASSES ARE STILL SUB-FREEZING IN
EASTERLY FLOW AND STILL RECEIVING A LITTLE LIGHT SNOW...THOUGH NO
REAL INCREASE IN SNOW DEPTH. PROBABLY A LITTLE FREEZING RAIN IS
OCCURRING NOT TOO FAR WEST OF THE PASSES. WILL HANG ON TO THE WINTER
WEATHER ADVISORY FOR THE CASCADES THROUGH 10 AM AS PLANNED. ADVISORY
SHOULD BE EXPIRING ABOUT WHEN THE PRECIP REALLY TAPERS OFF.
GFS/NAM DIFFERED IN THE 00Z RUNS FOR TONIGHT...WITH GFS PUTTING QPF
OVER THE AREA...CAUSED BY A WEAK VORT MAX EMBEDDED IN THE SW FLOW ON
THE UPSTREAM SIDE OF THE UPPER LEVEL RIDGE. 06Z GFS HAS SINCE
MIGRATED CLOSER TO THE DRIER NAM SOLUTION. ELECTED TO STAY WITH THE
DRY FORECAST TONIGHT...THOUGH MOS POPS ARE 15-20 PERCENT.
THE UPPER LEVEL RIDGE AXIS IS OVER MONTANA BY SUNDAY AFTERNOON
WITH GRADUALLY INCREASING SW FLOW ALOFT OVER WESTERN WA. BOTH
NAM/GFS HAVE A SMALL WEAK SHORT-WAVE TROUGH APPROACHING THE COAST IN
THE AFTERNOON. AIR MASS REMAINS MOIST...SO EVEN THE WEAK UPWARD
MOTION GENERATED BY THIS WAVE SHOULD BE ENOUGH TO WRING OUT SOME
LIGHT RAIN...CHANCE POPS FINE FOR NOW. ANOTHER WEAK SHORT-WAVE IN
THE SERIES DOES THE SAME THING ON MONDAY.
.LONG TERM...NEXT SIGNIFICANT SYSTEM SHOULD BE A STRONG COLD
FRONT...APPROACHING MONDAY NIGHT AND HEADING EAST LATE TUESDAY.
GFS/ECMWF/NAM ALL HAVE SOMEWHAT SIMILAR STRENGTH AND TIMING...JUST
DIFFERENT HANDLES ON THE SURFACE LOW HEADING TOWARD VANCOUVER
ISLAND. SIGNIFICANT EFFECT FROM ALL SOLUTIONS IS THE INCREASING SE
GRADIENT FOR WINDY IN THE TYPICAL SE EXPOSED AREAS. SHOWERY...
COOLER...SNOW LEVEL-BELOW-THE-PASSES WEATHER SHOULD ENSUE AFTER THE
COLD FRONT TUESDAY NIGHT...AS A NICE BIG UPPER LEVEL TROUGH SETS UP
OFFSHORE AND LASTS THROUGH AT LEAST THURSDAY. KAM
&&
.AVIATION...MOIST AIR MASS IN THE LOW LEVELS THROUGH THIS EVENING.
THE WARM FRONT EASES NE AND RAIN CHANGES TO DRIZZLE...AND AS THE MID
LEVEL DRIES UP JUST LOW STRATUS IS LEFT BEHIND. SO...EXPECTING
LITTLE IMPROVEMENT TODAY EVEN AS 1030MB SFC HIGH BUILDS OVER THE SW
PART OF WA BY 00Z. FOR THAT MATTER...I AM NOT SURE THAT ENOUGH
OFFSHORE FLOW WILL DRYING THINGS OUT TONIGHT SO FOG MAY DEVELOP EVEN
AS STRATUS FINALLY DRIES UP TONIGHT.
$$
.SEW WATCHES/WARNINGS/ADVISORIES...
.WINTER WEATHER ADVISORY NORTH AND CENTRAL CASCADES THROUGH 10 AM
SAT.
.SMALL CRAFT ADVISORY FOR ROUGH BAR CONDITIONS ON THE GRAYS HARBOR
BAR.
$$
WEATHER.GOV/SEATTLE
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
315 PM CST SUN MAR 4 2007
.SHORT TERM...TONIGHT AND MONDAY. FORECAST FOCUS ON SNOW CHANCES AND
TEMPERATURES.
A COLD FRONT WITH MUCH COOLER AIR IS EXPECTED TO MOVE THRU THE CWA
TONIGHT. THE MODEL TRENDS HAVE BEEN FOR A BIT QUICKER MOVEMENT OF THIS
FRONT AS MOS TEMPERATURES ARE SEVERAL DEGREES COLDER THIS RUN. THEREFORE
WILL LOWER TEMPS TONIGHT A FEW DEGREES TO MATCH THE MODEL TRENDS.
UPSTREAM TAMDAR SOUNDINGS SHOW THE AIR ASSOCIATED WITH THIS FRONT IS
FAIRLY DRY WHICH IS REFLECTED IN THE MODEL POPS/QPF. GIVEN THIS DRY AIR
WILL LOWER POPS A BIT WITH A CHANCE ACROSS PORTIONS OF NORTH CENTRAL
WHERE THE BEST MOISTURE/DYNAMICS WILL BE WITH ONLY FLURRIES SOUTH. WINDS
PICK UP A BIT WITH THE FRONT...HOWEVER THE HIGH AMOUNT OF LIQUID WITH
THE SNOWFALL SHOULD PREVENT MUCH BLOWING SNOW ACROSS THE CWA. MODEL
TRENDS A BIT COOLER AND DRIER ON MONDAY AS THE FRONT MOVES EAST OF THE
AREA. WILL ADJUST FORECAST TO REFLECT THIS TREND.
.LONG TERM...MONDAY NIGHT THRU NEXT SUNDAY. MAIN CHANGE THIS PERIOD TO
LOWER TEMPS THROUGHOUT AND TIGHTEN UP PCPN CHANCES. IN THE BIG
PICTURE...MODELS NOT TOO DIFFERENT. REGION TO REMAIN UNDER NORTHWEST
FLOW...SOME DEAMPLIFICATION OF PATTERN LATE IN WORK WEEK WITH WESTERN
RIDGE SLIDING EAST...THOUGH RIDGE TO BUILD IN AGAIN OVER THE WEST FOR
THE WEEKEND. TWO PERIODS FOR PCPN CHANCES...TUE TIMEFRAME IN WAA REGIME
AHEAD OF CLIPPER TYPE SYSTEM AND AGAIN LATER THU INTO FRI WITH UPPER
TROF MOVING EAST THROUGH THE NORTHERN PLAINS/GREAT LAKES. PLAYED
CONSERVATIVE ON WEEKEND TEMPS...BELOW MEX GUIDANCE (CLOSER TO ENSEMBLE
MEAN) AS SURFACE COLD FRONT MOVES THROUGH EARLY SAT AND CAA REGIME SETS
UP. EARLY PERIODS TO REMAIN BELOW NORMAL IN TEMPS. TEMPS UNDER RIDGE
UPSTREAM STILL NEAR ZERO OR BELOW AT MID DAY. THIS AIR MASS HEADING
THIS WAY FOR MON INTO MON NIGHT. HAVE STAYED CLOSE TO WARMER NAM
GUIDANCE AT THIS TIME WITH WAA CLOUDS EXPECTED OVERNIGHT.
BUMPED POPS TO LIKELY TUE WITH 1 TO 3 INCHES OF SNOW EXPECTED AT THIS
TIME. GOOD ISENTROPIC LIFT ON 290K SURFACE FOR PERIOD OF 6 TO 12 HOURS.
SPECIFIC HUMIDITIES AROUND 3G/KG WITH HIGHER SNOW TO LIQUID RATIO
EXPECTED THAN WITH PAST STORM. MOISTURE AND LIFT ALSO EXTEND UP TO
REGION OF SIG SNOW GROWTH. PROBLEM...IS DRIER AIR SEEN AROUND 925 MB.
&&
AVIATION...VFR VISBYS WITH MVFR CIGS ACRS NORTH CNTRL WITH PDS OF MVFR
CIGS ACRS CNTRL AND NERN WI TONIGHT AND EARLY MONDAY AS A CD FNT MOVES
THRU. VFR CONDITIONS LTR MONDAY BEHIND FNTL BNDRY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
KURIMSKI/TE
WEATHER.GOV/GREENBAY
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