AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
700 AM EST FRI MAR 2 2007
.UPDATE...
AVIATION /12Z-12Z/...
AT 630 AM, CEILINGS WERE GENERALLY IN THE IFR TO LOW MVFR CATEGORY
AND VISIBILITIES WERE MAINLY MVFR.
BULK OF PRECIPITATION IS NOW MOVING OUT OF THE AREA...A LITTLE
FASTER THAN PREVIOUSLY ANTICIPATED. SOME NEW CONVECTION IS
DEVELOPING TO OUR SOUTHWEST AND WE MAY STILL SEE SOME CONVECTION UP
INTO OUR REGION ALTHOUGH IT IS A LOW PROBABILITY EVENT.
SOUTHERLY SURFACE WINDS TO THE SOUTH OF THE COASTAL FRONT ARE
BLOWING STRONGER THAN PREVIOUSLY FORECAST AND THE NEW 12Z TAF
ISSUANCE HAS BEEN ADJUSTED BASED ON CURRENT CONDITIONS.
WITH MOST PRECIPITATION IN THE PROCESS OF PULLING OUT...LOOKING FOR
CEILINGS TO HOLD STEADY AND VISIBILITY TO HOLD STEADY OR IMPROVE
SLIGHTLY LEADING UP TO 15Z TIMEFRAME.
06Z MODEL RUNS CONTINUE TO SUPPORT HIGH CONFIDENCE FORECAST OF RAPID
IMPROVEMENT TO VFR CONDITIONS LATER TODAY. TRANSITION TO VFR
EXPECTED IN 16Z TO 19Z TIMEFRAME. WINDS WILL SWING AROUND TO WEST
IN THE LATE MORNING AND GUST TO 25 KT DURING THE AFTERNOON.
PREVIOUS AFD ISSUED AT 417 AM MAR 2 2007
SHORT TERM /TODAY THROUGH SUNDAY/...
RAIN MOVED IN ON SCHEDULE. DID HAVE A FEW RUMBLES OF THUNDER EARLY
OVER SOUTHERN NJ AND SE PA. COULD HAVE SOME MORE WITHIN THE NEXT
4 TO 6 HOURS. MODELS ARE MOVING THE HEAVY RAIN RAPIDLY OUT OF OUR
AREA BY MIDDAY...SO WILL CUT BACK THE ENDING TIME FOR THE FLOOD
WATCH TO 1 PM. IN AREAS WHERE THERE IS A CONSIDERABLE SNOW PACK...
MAINLY POCONOS...ANY SIGNIFICANT SNOWMELT AND ICE JAM BREAKUPS
COULD CAUSE FLOODING LATER IN THE DAY. WE WILL HANDLE THAT, IF
IT OCCURS WITH WARNINGS. RAINFALL AMOUNTS, SO FAR, MAY BE PUSHING
ONE INCH IN SOME LOCATIONS. THE ONLY AREA WARNED ATTM IS CHESTER
COUNTY IN PA...THE BRANDYWINE CREEK IN PARTICULAR. WITH THE MILD
AIR STREAMING INTO OUR AREA...WE HAVE LET OUR ADVISORY EXPIRE IN
THE NORTH. WHILE THERE MAY STILL BE A FEW ISOLATED POCKETS OF
FREEZING TEMPERATURES, MOST READINGS HAVE CLIMBED ABOVE THAT
MARK. AND WHERE THEY ARE STILL AT OR SLIGHTLY BELOW, THEY SHOULD
RISE ABOVE WITHIN THE NEXT HOUR OR TWO. ONCE THE FRONTAL SYSTEM
MOVES OUT OF OUR AREA, RAPID CLEARING IS EXPECTED. SHOULD SEE
PLENTY OF SUNSHINE THIS AFTERNOON. A SECONDARY SURGE OF COLD AIR
WILL CROSS THE REGION SATURDAY AS THE UPPER TROUGH MOVES EAST
NORTHEAST FROM THE GREAT LAKES. SCATTERED SHOWERS MAY PRECEDE
AND ACCOMPANY THIS COLD PUSH. THERE MAY EVEN BE A FEW SCATTERED
TSTMS SATURDAY AFTERNOON OR EVENING AS THE CONVERGENCE ZONE
INCREASES. AFTER ALL, THIS IS MARCH. A NW FLOW OF COLDER AIR
MOVES INTO OUR REGION SATURDAY NIGHT THROUGH SUNDAY.
&&
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE EAST COAST TROUGH HANGS AROUND FOR THE EARLY PART OF THE
EXTENDED. ANOTHER, EVEN COLDER, SURGE DROPS ACROSS THE REGION
LATE MONDAY INTO MONDAY NIGHT. LATER IN PERIOD, THE FLOW BECOMES
MORE ZONAL, BRINGING MILDER AIR BACK INTO THE REGION BY WEDNESDAY
NIGHT AND THURSDAY.
&&
.AVIATION...
AT 1230 AM, CEILINGS WERE GENERALLY IN THE IFR CATEGORY WITH A FEW
LOCATIONS TOUCHING LIFR. VSBYS WERE GENERALLY MVFR WITH IFR
CONDITIONS IN THE HEAVIER PRECIPITATION.
MOS GUIDANCE DID NOT CAPTURE WELL THE DEVELOPMENT AND INLAND PUSH OF
COASTAL FRONT...WITH SSE WINDS TO THE SOUTH OF THE FRONT AND NE
WINDS TO THE NORTH. 06Z TAF ISSUANCE PLAYED UP THIS WIND DIRECTION
DIFFERENCE AND BROUGHT COASTAL FRONT UP INTO VICINITY OF I95
CORRIDOR AIRPORTS (ILG...PHL...PNE...TTN).
THE HEAVIEST OF THE RAIN SHOULD FALL FROM NOW UNTIL AROUND 9:00 AM.
IFR CONDITIONS ARE LIKELY THOUGH MOST OF THAT PERIOD...PARTICULARLY
IN THE SECTOR NORTH AND WEST OF THE COASTAL FRONT. FOR THE EARLY
MORNING HOURS, WE`VE ALSO KEPT THE MENTION OF CUMULONIMBUS CLOUDS
(CB) TO SUGGEST THE POSSIBILITY OF SCATTERED TSTMS ALONG WITH THE
MENTION OF LOW LEVEL WIND SHEAR. 00Z MODEL RUNS CONTINUE TO SUGGEST
THE DEVELOPMENT OF A STRONG SOUTH SOUTHEAST LOW LEVEL JET OVER OUR
REGION...AND THIS IS SUPPORTED BY LATEST ACARS DATA FROM PHL. MOVED
START TIME OF LLWS IN THE TAFS SOONER BY ABOUT AN HOUR BASED ON
ACARS DATA.
06Z NAM MODEL RUN CONTINUES TO SUPPORT HIGH CONFIDENCE FORECAST OF
RAPID IMPROVEMENT TO VFR CONDITIONS. TIMING SLIGHTLY
SLOWER...EXPECTED NOW 16Z TO 19Z TIMEFRAME. WINDS WILL SWING AROUND
TO WEST IN THE LATE MORNING AND GUST TO 25 KT DURING THE AFTERNOON.
&&
.MARINE...
GALE WARNING HEADLINES CONTINUE. NO CHANGE TO PREVIOUS COVERAGE AND
TIMING. SE FLOW OVER COLD WATER HAVING TROUBLE REACHING SPEEDS
ADVERTISED IN MODELS...BUT STILL EXPECT TO SEE GALE FORCE GUSTS.
NEW WAVEWATCH SUPPORTS PREVIOUS SEAS FORECAST SO NO SIGNIFICANT
CHANGE IN THAT AREA EITHER. GUIDANCE SUGGESTS THE GALES WOULD HOLD
ON A BIT LONGER NORTH THAN SOUTH AS THE SYSTEM LIFTS NORTHEAST, AND
WE ACCOUNT FOR THAT.
&&
TIDES...
HAVE DROPPED COASTAL FLOOD ADVISORY FOR ATLANTIC COAST SECTIONS OF
NEW JERSEY AND DELAWARE AS WELL AS FOR MARYLAND PORTION OF
CHESAPEAKE BAY. DEPARTURES ARE NOT RUNNING AS HIGH AS PREVIOUSLY
ANTICIPATED. HAVE LEFT ADVISORY UP FOR TIDAL DELAWARE AREA AS
STRONG SSE LOW LEVEL FLOW STILL HAS POTENTIAL TO PUSH WATER UP INTO
THAT REGION AND ACHIEVE MINOR TIDAL FLOODING LEVELS DURING HIGH
TIDE LATER TODAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR PAZ054-055-
060>062-067>071.
COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 1 PM EST THIS
AFTERNOON FOR PAZ070-071.
NJ...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR NJZ001-007>010-
012-015-017>019.
COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 1 PM EST THIS
AFTERNOON FOR NJZ016>019-021.
DE...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR DEZ001.
COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 1 PM EST THIS
AFTERNOON FOR DEZ001-002.
MD...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR MDZ008.
MARINE...GALE WARNING UNTIL 11 AM EST THIS MORNING FOR ANZ430-431-
452>455.
GALE WARNING UNTIL 3 PM EST THIS AFTERNOON FOR ANZ450-451.
&&
$$
SHORT TERM/LONG TERM...RPW
AVIATION/MARINE/TIDES...GSS
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
417 AM EST FRI MAR 2 2007
SHORT TERM /TODAY THROUGH SUNDAY/...
RAIN MOVED IN ON SCHEDULE. DID HAVE A FEW RUMBLES OF THUNDER EARLY
OVER SOUTHERN NJ AND SE PA. COULD HAVE SOME MORE WITHIN THE NEXT
4 TO 6 HOURS. MODELS ARE MOVING THE HEAVY RAIN RAPIDLY OUT OF OUR
AREA BY MIDDAY...SO WILL CUT BACK THE ENDING TIME FOR THE FLOOD
WATCH TO 1 PM. IN AREAS WHERE THERE IS A CONSIDERABLE SNOW PACK...
MAINLY POCONOS...ANY SIGNIFICANT SNOWMELT AND ICE JAM BREAKUPS
COULD CAUSE FLOODING LATER IN THE DAY. WE WILL HANDLE THAT, IF
IT OCCURS WITH WARNINGS. RAINFALL AMOUNTS, SO FAR, MAY BE PUSHING
ONE INCH IN SOME LOCATIONS. THE ONLY AREA WARNED ATTM IS CHESTER
COUNTY IN PA...THE BRANDYWINE CREEK IN PARTICULAR. WITH THE MILD
AIR STREAMING INTO OUR AREA...WE HAVE LET OUR ADVISORY EXPIRE IN
THE NORTH. WHILE THERE MAY STILL BE A FEW ISOLATED POCKETS OF
FREEZING TEMPERATURES, MOST READINGS HAVE CLIMBED ABOVE THAT
MARK. AND WHERE THEY ARE STILL AT OR SLIGHTLY BELOW, THEY SHOULD
RISE ABOVE WITHIN THE NEXT HOUR OR TWO. ONCE THE FRONTAL SYSTEM
MOVES OUT OF OUR AREA, RAPID CLEARING IS EXPECTED. SHOULD SEE
PLENTY OF SUNSHINE THIS AFTERNOON. A SECONDARY SURGE OF COLD AIR
WILL CROSS THE REGION SATURDAY AS THE UPPER TROUGH MOVES EAST
NORTHEAST FROM THE GREAT LAKES. SCATTERED SHOWERS MAY PRECEED
AND ACCOMPANY THIS COLD PUSH. THERE MAY EVEN BE A FEW SCATTERED
TSTMS SATURDAY AFTERNOON OR EVENING AS THE CONVERGENCE ZONE
INCREASES. AFTER ALL, THIS IS MARCH. A NW FLOW OF COLDER AIR
MOVES INTO OUR REGION SATURDAY NIGHT THROUGH SUNDAY.
&&
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE EAST COAST TROUGH HANGS AROUND FOR THE EARLY PART OF THE
EXTENDED. ANOTHER, EVEN COLDER, SURGE DROPS ACROSS THE REGION
LATE MONDAY INTO MONDAY NIGHT. LATER IN PERIOD, THE FLOW BECOMES
MORE ZONAL, BRINGING MILDER AIR BACK INTO THE REGION BY WEDNESDAY
NIGHT AND THURSDAY.
&&
.AVIATION...
AT 1230 AM, CEILINGS WERE GENERALLY IN THE IFR CATEGORY WITH A FEW
LOCATIONS TOUCHING LIFR. VSBYS WERE GENERALLY MVFR WITH IFR
CONDITIONS IN THE HEAVIER PRECIPITATION.
MOS GUIDANCE DID NOT CAPTURE WELL THE DEVELOPMENT AND INLAND PUSH OF
COASTAL FRONT...WITH SSE WINDS TO THE SOUTH OF THE FRONT AND NE
WINDS TO THE NORTH. 06Z TAF ISSUANCE PLAYED UP THIS WIND DIRECTION
DIFFERENCE AND BROUGHT COASTAL FRONT UP INTO VICINITY OF I95
CORRIDOR AIRPORTS (ILG...PHL...PNE...TTN).
THE HEAVIEST OF THE RAIN SHOULD FALL FROM NOW UNTIL AROUND 9:00 AM.
IFR CONDITIONS ARE LIKELY THOUGH MOST OF THAT PERIOD...PARTICULARLY
IN THE SECTOR NORTH AND WEST OF THE COASTAL FRONT. FOR THE EARLY
MORNING HOURS, WE`VE ALSO KEPT THE MENTION OF CUMULONIMBUS CLOUDS
(CB) TO SUGGEST THE POSSIBILITY OF SCATTERED TSTMS ALONG WITH THE
MENTION OF LOW LEVEL WIND SHEAR. 00Z MODEL RUNS CONTINUE TO SUGGEST
THE DEVELOPMENT OF A STRONG SOUTH SOUTHEAST LOW LEVEL JET OVER OUR
REGION...AND THIS IS SUPPORTED BY LATEST ACARS DATA FROM PHL. MOVED
START TIME OF LLWS IN THE TAFS SOONER BY ABOUT AN HOUR BASED ON
ACARS DATA.
06Z NAM MODEL RUN CONTINUES TO SUPPORT HIGH CONFIDENCE FORECAST OF
RAPID IMPROVEMENT TO VFR CONDITIONS. TIMING SLIGHTLY
SLOWER...EXPECTED NOW 16Z TO 19Z TIMEFRAME. WINDS WILL SWING AROUND
TO WEST IN THE LATE MORNING AND GUST TO 25 KT DURING THE AFTERNOON.
&&
.MARINE...
GALE WARNING HEADLINES CONTINUE. NO CHANGE TO PREVIOUS COVERAGE AND
TIMING. SE FLOW OVER COLD WATER HAVING TROUBLE REACHING SPEEDS
ADVERTISED IN MODELS...BUT STILL EXPECT TO SEE GALE FORCE GUSTS.
NEW WAVEWATCH SUPPORTS PREVIOUS SEAS FORECAST SO NO SIGNIFICANT
CHANGE IN THAT AREA EITHER. GUIDANCE SUGGESTS THE GALES WOULD HOLD
ON A BIT LONGER NORTH THAN SOUTH AS THE SYSTEM LIFTS NORTHEAST, AND
WE ACCOUNT FOR THAT.
&&
TIDES...
HAVE DROPPED COASTAL FLOOD ADVISORY FOR ATLANTIC COAST SECTIONS OF
NEW JERSEY AND DELAWARE AS WELL AS FOR MARYLAND PORTION OF
CHESAPEAKE BAY. DEPARTURES ARE NOT RUNNING AS HIGH AS PREVIOUSLY
ANTICIPATED. HAVE LEFT ADVISORY UP FOR TIDAL DELAWARE AREA AS
STRONG SSE LOW LEVEL FLOW STILL HAS POTENTIAL TO PUSH WATER UP INTO
THAT REGION AND ACHIEVE MINOR TIDAL FLOODING LEVELS DURING HIGH
TIDE LATER TODAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR PAZ054-055-
060>062-067>071.
COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 1 PM EST THIS
AFTERNOON FOR PAZ070-071.
NJ...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR NJZ001-007>010-
012-015-017>019.
COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 1 PM EST THIS
AFTERNOON FOR NJZ016>019-021.
DE...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR DEZ001.
COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 1 PM EST THIS
AFTERNOON FOR DEZ001-002.
MD...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR MDZ008.
MARINE...GALE WARNING UNTIL 11 AM EST THIS MORNING FOR ANZ430-431-
452>455.
GALE WARNING UNTIL 3 PM EST THIS AFTERNOON FOR ANZ450-451.
&&
$$
SHORT TERM/LONG TERM...RPW
AVIATION/MARINE/TIDES...GSS
AREA FORECAST DISCUSSION...UPDATED
NWS MOUNT HOLLY NJ
124 AM EST FRI MAR 2 2007
.UPDATE...
AVIATION /06Z-06Z/...
AT 1230 AM, CEILINGS WERE GENERALLY IN THE IFR CATEGORY WITH A FEW
LOCATIONS TOUCHING LIFR. VSBYS WERE GENERALLY MVFR WITH IFR
CONDITIONS IN THE HEAVIER PRECIPITATION.
MOS GUIDANCE DID NOT CAPTURE WELL THE DEVELOPMENT AND INLAND PUSH OF
COASTAL FRONT...WITH SSE WINDS TO THE SOUTH OF THE FRONT AND NE
WINDS TO THE NORTH. 06Z TAF ISSUANCE PLAYED UP THIS WIND DIRECTION
DIFFERENCE AND BROUGHT COASTAL FRONT UP INTO VICINITY OF I95
CORRIDOR AIRPORTS (ILG...PHL...PNE...TTN).
THE HEAVIEST OF THE RAIN SHOULD FALL FROM NOW UNTIL AROUND 9:00
AM. IFR CONDITIONS ARE LIKELY THOUGH MOST OF THAT PERIOD. FOR THE
EARLY MORNING HOURS, WE`VE ALSO KEPT THE MENTION OF CUMULONIMBUS
CLOUDS (CB) TO SUGGEST THE POSSIBILITY OF SCATTERED TSTMS ALONG WITH
THE MENTION OF LOW LEVEL WIND SHEAR. 00Z MODEL RUNS CONTINUE
TO SUGGEST THE DEVELOPMENT OF A STRONG SOUTH SOUTHEAST LOW LEVEL JET
OVER OUR REGION...AND THIS IS SUPPORTED BY LATEST ACARS DATA FROM
PHL. MOVED START TIME OF LLWS IN THE TAFS SOONER BY ABOUT AN HOUR
BASED ON ACARS DATA.
00Z MODEL RUNS CONTINUE TO SUPPORT HIGH CONFIDENCE FORECAST OF RAPID
IMPROVEMENT TO VFR CONDITIONS IN 15Z TO 18Z TIMEFRAME. WINDS WILL
SWING AROUND TO WEST IN THE LATE MORNING AND GUST TO 25 KT DURING
THE AFTERNOON. THESE CONDITIONS REFLECTED IN TAFS.
PREV DISCUSSION...
/ISSUED 952 PM EST THU MAR 1 2007/
THE PUBLIC PRODUCTS HAVE BEEN REISSUED TO INCLUDE A WINTER WEATHER
ADVISORY FOR CARBON, MONROE AND NORTHAMPTON COUNTIES OF NORTHEAST
PENNSYLVANIA AND SUSSEX AND WARREN COUNTIES OF NEW JERSEY. WE HAVE
RECEIVED A FEW CALLS FROM SPOTTERS WITH REPORTS OF FREEZING RAIN
AND LIGHT ACCUMULATIONS. THE WSW WILL BE IN EFFECT UNTIL 2 AM...
BY THEN THE WARMER AIR WILL HAVE CAUSED THE MIXED PRECIP TO CHANGE
TO ALL RAIN. AFTER THAT... THE RAIN HEAVY AT TIMES WORDING WILL
REMAIN FOR THE OVERNIGHT IN ALL AREAS AND THE FLOOD WATCH
CONTINUES. THE COASTAL FLOOD ADVISORY HAS BEEN EXPANDED TO INCLUDE
THE REMAINDER OF OUR WATERS THROUGH THE FIRST HALF OF FRIDAY.
PREV DISCUSSION...
/ISSUED 650 PM EST THU MAR 1 2007/
AVIATION /00Z-24Z/...
AT 6:45 PM, CEILINGS WERE GENERALLY IN THE VFR CATEGORY WITH MAINLY
UNRESTRICTED VSBY AT OUR EIGHT TAF SITES. THE LEADING EDGE OF THE
RAIN WAS ALREADY UP INTO EASTERN MARYLAND. AS A RESULT, WE`LL
CONTINUE WITH THE IDEA OF GRADUALLY DETERIORATING CONDITIONS THROUGH
MIDNIGHT.
THE HEAVIEST OF THE RAIN SHOULD FALL FROM MIDNIGHT UNTIL AROUND 9:00
AM. IFR CONDITIONS ARE LIKELY THOUGH MOST OF THAT PERIOD. FOR THE
LATE NIGHT AND EARLY MORNING HOURS ON FRIDAY, WE`VE ALSO KEPT THE
MENTION OF CUMULONIMBUS CLOUDS (CB) TO SUGGEST THE POSSIBILITY OF
SCATTERED TSTMS ALONG WITH THE MENTION OF LOW LEVEL WIND SHEAR.
THE MODELS CONTINUE TO SUGGEST THE DEVELOPMENT OF A STRONG SOUTH
SOUTHEAST LOW LEVEL JET OVER OUR REGION. DURING THE HOURS RIGHT
AROUND DAYBREAK IT SHOULD BE WITHIN 2000 FEET OF THE SURFACE AND SO
THE LLWS HAS BEEN INCLUDED IN THE TAFS.
THE GUIDANCE CONTINUES TO INDICATE THAT THE PRECIP WILL SHUT OFF
AROUND MID MORNING WITH SOME LINGERING LOW CLOUDS BEFORE RAPID
CLEARING IN THE EARLY AFTERNOON.
PREV DISCUSSION...
/ISSUED 329 PM EST THU MAR 1 2007/
LONG TERM /SUNDAY THROUGH THURSDAY/...
EAST COAST TROUGH HANGS AROUND FOR THE EARLY PART OF THE EXTENDED.
LATER IN PERIOD FLOW BECOMES MORE ZONAL. DRY QUIET WEATHER WITH NEAR
SEASONABLE TEMPERATURES EXPECTED.
MARINE...
WE HAVE DROPPED THE SCA HEADLINE AND GONE TO STRAIGHT GALES. THE WRF
IS LESS EMPHATIC ABOUT GALE FORCE WINDS/GUST OVER THE NRN WATERS
THAN THE GFS; THE GFS HAS BACKED OFF A BIT FROM THE PREVIOUS RUN AND
WE ARE LOOKING AT A SERLY FLOW OVER COLD WATER. HOWEVER, WE THINK
WE`LL GET TO GALES REGARDING GUSTS. LEANED MORE TOWARD WAVEWATCH
REGARDING THE SEAS, WHICH MEANS WE UPPED THEM A LTL IN THE
PRE-SYSTEM ENVIRONMENT. GUIDANCE SUGGESTS THE GALES WOULD HOLD ON A
BIT LONGER NORTH THAN SOUTH AS THE SYSTEM LIFTS NORTHEAST, AND WE
ACCOUNT FOR THAT.
HYDROLOGY...
EXPECTING A GOOD SOAKING RAIN WITH QPF IN THE 1.5 TO 2 INCH RANGE
WITH LOCALLY HIGHER AMOUNTS. RAINFALL WILL BE QUICK SHOT WITH THE
BULK OF IT FALLING IN A 6 TO 12 HOUR TIME FRAME. LOCAL PROCEDURES
SHOW SMALL STREAMS IN NORTHERN DELAWARE AND SOUTHEAST PENNSYLVANIA
REACHING MODERATE FLOOD LEVELS WITH THESE AMOUNTS. LARGER STREAMS
AND RIVERS IN SOUTHEAST PENNSYLVANIA AND NEW JERSEY MAY REACH MINOR
FLOOD LEVELS. AT PRESENT THE LARGE MAIN STEM RIVERS SUCH AS THE
SCHUYLKILL...LEHIGH AND DELAWARE WILL SHOW SIGNIFICANT WITHIN BANKS
RISES BUT NO FLOODING EXPECTED.
TIDES...
POSITIVE TIDAL DEPARTURES EARLY THIS AFTERNOON ARE RUNNING ABOVE THE
SSE AND BELOW THE ECS GUIDANCE. A COMPROMISE BETWEEN THE TWO WOULD
HAVE AREAS OF MINOR TIDAL FLOODING ALONG OUR MOST FLOOD-PRONE
LOCATIONS. THE CBOFS FORECAST FOR CAMBRIDGE IS NOT TERRIBLY
IMPRESSIVE, BUT THE FORECAST FOR TOLCHESTER HAS BEEN TAKING IT ABOVE
MINOR TIDAL FLOODING FOR THE PAST TWO RUNS. HIGH TIDES OCCUR A FEW
HOURS ON EITHER SIDE OF DAYBREAK ON THE CHESAPEAKE, EARLIER SOUTH
THAN NORTH, AND THIS PUTS IT IN THE WINDOW FOR AN ADVISORY. ONE HAS
BEEN ISSUED. ELSEWHERE, HIGH TIDES OCCUR FROM DAYBREAK INTO THE LATE
MORNING FOR THE ATLANTIC COASTAL SECTIONS, ADJACENT BACK BAYS,
RARITAN BAY AND DELAWARE BAY. THESE ARE BEYOND THE ADVISORY WINDOW
AND SO WE HAVE ISSUED A SPS FOR THEM. WE ALSO HAVE INCLUDED THE
TIDAL DELAWARE IN THAT SPS BECAUSE OF INDICATIONS FROM THE SSE, EVEN
THOUGH HIGH TIDES THERE RUN FROM LATE MORNING INTO EARLY AFTERNOON
WHEN THE SYSTEM SHOULD BE PAST US.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH THROUGH FRIDAY EVENING FOR PAZ054-055-060>062-
067>071.
COASTAL FLOOD ADVISORY FROM 7 AM TO 1 PM EST FRIDAY FOR PAZ070-
071.
WINTER WEATHER ADVISORY UNTIL 2 AM EST FRIDAY FOR PAZ054-055-
062.
NJ...FLOOD WATCH THROUGH FRIDAY EVENING FOR NJZ001-007>010-012-015-
017>019.
COASTAL FLOOD ADVISORY FROM 7 AM TO 1 PM EST FRIDAY FOR
NJZ016>019-021.
COASTAL FLOOD ADVISORY FROM 3 AM TO 9 AM EST FRIDAY FOR
NJZ012>014-020-022>027.
WINTER WEATHER ADVISORY UNTIL 2 AM EST FRIDAY FOR NJZ001-007.
DE...FLOOD WATCH THROUGH FRIDAY EVENING FOR DEZ001.
COASTAL FLOOD ADVISORY FROM 7 AM TO 1 PM EST FRIDAY FOR DEZ001-
002.
COASTAL FLOOD ADVISORY FROM 3 AM TO 9 AM EST FRIDAY FOR DEZ003-
004.
MD...FLOOD WATCH THROUGH FRIDAY EVENING FOR MDZ008.
COASTAL FLOOD ADVISORY FROM 3 AM TO 9 AM EST FRIDAY FOR MDZ008-
012-015-019-020.
MARINE...GALE WARNING UNTIL 11 AM EST FRIDAY FOR ANZ430-431-452>455.
GALE WARNING UNTIL 3 PM EST FRIDAY FOR ANZ450-451.
&&
$$
UPDATE...PO/SZATKOWSKI
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
310 PM CST SAT MAR 3 2007
.DISCUSSION FOR AFTERNOON GRIDS/ZONES UPDATE...
310 PM CST
LAST SHORT WAVE OF THIS SYSTEM MOVG THRU NOW ALONG WITH UPR TROF.
SHUD SEE END OF SNOW BY MDNGT OVER ALL CWA...GRADUALLY ENDING FROM
WEST. WINDS A BIT BLUSTERY TODAY BUT NOTHING LIKE YDA AS SFC LOW
QUEBEC FILLING AND PULLING OUT TOWARD THE NEW ENGLAND COAST TNGT.
CYCLONIC FLOW TERMINATING TONGT AS RIDGE MOVE INTO MIDWEST. EXPECT
SKIES TO CLEAR TONIGHT WITH DECENT SUBSIDENCE BUT WINDS STILL A BIT
BRISK TO 15 MPH OVERNIGHT TO KEEP MIXING STEADY AND TEMPS UP TO NEAR
MOS VALUES...WHICH ARE RATHER COMPARABLE.
HAVE ENTERED PATTERN OF NW UPR FLOW UNTIL THURSDAY. IN THIS FLOW
WILL SLIP DOWN A FEW WEAK WAVES OVER NEXT FEW DAYS THREATENING AREA
WITH RECURRING SNOW CHANCES. FOR NOW WILL EXPECT A RATHER SUNNY DAY
ON SUNDAY AND CLEAR TO PTCLDY SUN NGT WITH RECEDING SFC RIDGE TO OUR
SOUTH. THE NEXT WAVE DROPPING DOWN LK MICH BEHIND THIS RIDGE SUNDAY
NGT. NAM TAKING THIS WAVE MORESO OVER LWR MICH WHILE GFS MOVING
ANOTHER BAND OF ASSOCIATED SNOW SHOWERS THRU CWA ON MONDAY. HAVE
OPTED FOR A BLEND HERE AND BROUGHT A RISK OF SNOW SHOWERS TO THE FAR
NORTHEAST BEFORE PULLING OFF TO THE EAST ACROSS LOWER MICH. ANOTHER
RIDGE DROPPING BEHIND THIS WAVE MON NGT AND TUESDAY. WITH WAA
RETURNING AHEAD OF THIS WAVE...WILL BE LOOKING AT A WINTER MIX WITH
RAIN MORE PROBABLY IN FAR SRN SECTIONS OF FCST AREA.
MOVING INTO A BROAD UPR RIDGE ON THURSDAY...TEMPS WARMING INTO THE
40S AND EVEN SOME 50S BEFORE A THREAT OF RAIN FALLS INTO THE PICTURE
ON FRIDAY AS A FNTL SYSTEM DEEPENS AND SWINGS ACROSS THE GREAT LAKES
AND MISSISSIPPI VLY. HIGH PRESSURE BLDG IN FOR THE WEEKEND WITH ONLY
MINOR CAA BEHIND THIS NEXT FNT SHUD. THAT COMBINED WITH EXPECTED
SUNSHINE SHUD BE ONE OF FIRST PLEASANT WEEKENDS IN SOME TIME.
RLB
&&
.AVIATION DISCUSSION FOR 18Z TAFS...
1200 PM CST
THE LAST IN A SERIES OF SHORT WAVE TROUGHS CURRENTLY TRACKING ACROSS
FAR NORTHEAST ILLINOIS WILL BRING ANOTHER ROUND OF LIGHT
SNOW/FLURRIES TO TERMINALS THROUGH MID AFTERNOON. MORE SUBSTANTIAL
SNOW SHOWER ACTIVITY IN ASSOCIATION WITH THIS WAVE APPEARS TO BE
ACROSS EXTREME NORTHEAST ILLINOIS AND FAR SOUTHEAST
WISCONSIN...GENERALLY REMAINING NORTH OF THE TERMINALS. WILL CARRY
MENTION OF MVFR VSBYS WITH THESE SNOW SHOWERS IN THE 18Z-21Z TIME
FRAME...BUT EXPECTING VSBYS TO REMAIN VFR AT RFD WHERE SFC DEW PTS
DEPRESSIONS HAVE NOW INCREASED TO 13 DEGREES UNDER THE INFLUENCE OF
LOW LEVEL DRY AIR ADVECTION AND MIXING. AFTER 21Z...PERHAPS A FEW
LINGERING FLURRIES BUT WILL OMIT ANY ADDITIONAL MENTION OF -SN FOR
NOW. WITH THE DRY AIR ADVECTION...CIGS HAVE INCREASED TO AOA 2K FT
AND EXPECTING CIGS TO COME UP A BIT MORE THROUGH THE REMAINDER OF
THE AFTERNOON. STRATOCU ACROSS SOUTHERN WISCONSIN WILL LIKELY
DISSIPATE SHORTLY AFTER SUNSET...AND WILL TREND TO MOSTLY CLEAR
SKIES AFT 02Z.
WINDS HAVE GENERALLY BEEN IN THE 290-310 DEGREE RANGE LATE THIS
MORNING. WIND PROFILES FROM REGIONAL ACARS SOUNDINGS INDICATING
MIXED LAYER WIND DIRECTIONS FROM 290-310 DEGREES SO EXPECTING A MORE
NORTHWESTERLY FAVORED SFC GRADIENT TO BE PARTIALLY OFFSET BY
VERTICAL MIXING HELPING TO KEEP DIRECTIONS NOT MUCH FURTHER NORTH
THAN 310 DEGREES. DID BACK OFF ON WIND GUSTS THIS AFTERNOON...WITH
ACARS WIND PROFILES/FORECAST SOUNDINGS SUGGESTING GUSTS UP TO 20
KNOTS BEFORE DIMINISHING TO AROUND 10 KNOTS TOWARD 02Z.
MARSILI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
.IL...NONE.
.IN...NONE.
.LM...SMALL CRAFT ADVISORY NEARSHORE WATERS THROUGH THIS AFTERNOON.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1200 PM CST SAT MAR 3 2007
.DISCUSSION FOR MORNING GRIDS/ZONES UPDATE...
330 AM CST
WINDS FINALLY SETTLING DOWN AS THE SFC LOW ASSD WITH THE STG LATE
SEASON WINTER STORM HAS MOVED TO NRN LOWER MICHIGAN AND FILLED
CONSIDERABLY...TO 992MB. THE SFC PRESSURE GRADIENT ACROSS THE LOCAL
AREAS HAS WEAKENED AND BECOME MORE WLY...BUT A SECONDARY SURGE OF
COLD AIR...ALONG WITH A WIND SHIFT TO NWLY...IS MOVING AROUND THE
SWRN QUADRANT OF THE SFC LOW. THE WIND SHIFT ASSOCIATED WITH A
TROUGH AXIS WILL ENTER NWRN IL BY AROUND SUNRISE AND MOVE THRU NRN
IL DURG THE MORNING HRS. THIS TROUGH IS THE SFC REFLECTION OF THE
LATEST IN A SERIES OF UPPER LEVEL IMPULSES ROTATING AROUND THE BACK
SIDE OF THE UPPER LOW. THIS IMPULSE WILL PROVIDE ENUF LIFT AND
DYNAMICS TO KEEP LIGHT SNOW IN THE FCST FOR TODAY. DO NOT FEEL THAT
SNOWFALL RATES WILL BE HAS HIGH AS YESTERDAY...NOR WILL COVERAGE BE
QUITE AS EXTENSIVE. SO FOR THE NEAR TERM...HAVE OPTED TO KEEP POPS
IN THE HIGH LIKELY RANGE TO ACCOUNT FOR THE LESS WIDESPREAD NATURE.
ALSO WINDS WILL CONSIDERABLY WEAKER TODAY...SO THE BLOWING AND
DRIFTING SEEN YESTERDAY WILL NOT BE AS BIG OF A CONCERN.
HOWEVER...WINDS WILL STILL BE IN THE 15-20KT RANGE...SO SOME BLOWING
AND DRIFTING...AND LOCAL VSBY REDUCTIONS ARE POSSIBLE IN THE WIDE
OPEN RURAL LOCATIONS. FOR THE REMAINDER OF THE SHORT TERM...HAVE
GENERALLY FOLLOWED ALONG WITH THE GFS PATTERN FOR THE LARGE SCALE
FEATURES...THOUGH THERE ARE REALLY NO SIGNIFICANT MODEL DIFFERENCES
FOR THE SHORT TERM.
FINALLY STARTING TO SEE SOME IMPROVEMENT AND MODERATION BY SUNDAY
NIGHT AND MONDAY AS UPPER RIDGING BEGINS TO BUILD IN FROM THE
SOUTHWEST. THE CLOUDY SKIES WILL FINALLY ALLOW SOME SUNSHINE
THROUGH ON SUNDAY. THOUGH TEMPS SHOULD REMAIN BELOW SEASONAL NORMAL
LEVELS THROUGH THE WEEKEND...A WARMING TREND WILL BEGIN EARLY NEXT
WEEK WITH HIGHS REACHING INTO THE 40S FOR SOUTHERN LOCATIONS BY
MONDAY AND SPREADING OVER THE WHOLE CWA BY WEDNESDAY. NOT MUCH
CHANGE TO THE FORECAST LEADING INTO THE LONGER TERM. THE GFS IS
STILL INDICATING THAN ANOTHER SHORT WAVE SHOULD DROP OUT OF CENTRAL
CANADA...INTO THE NRN PLAINS TUESDAY MORNING AND QUICKLY TRACKING
ACROSS THE UPPER MIDWEST. THIS WILL BRING THE NEXT SHOT OF
PCPN...BUT GIVEN THE WARMING TEMPS...PCPN TYPE WILL LIKELY BE MORE
LIQUID THAN FROZEN DURING THE DAYTIME HRS...BEFORE CHANGING OVER TO
LIGHT SNOW TUESDAY NIGHT/WEDNESDAY MORNING.
KREIN
&&
.AVIATION DISCUSSION FOR 18Z TAFS...
1200 PM CST
THE LAST IN A SERIES OF SHORT WAVE TROUGHS CURRENTLY TRACKING ACROSS
FAR NORTHEAST ILLINOIS WILL BRING ANOTHER ROUND OF LIGHT
SNOW/FLURRIES TO TERMINALS THROUGH MID AFTERNOON. MORE SUBSTANTIAL
SNOW SHOWER ACTIVITY IN ASSOCIATION WITH THIS WAVE APPEARS TO BE
ACROSS EXTREME NORTHEAST ILLINOIS AND FAR SOUTHEAST
WISCONSIN...GENERALLY REMAINING NORTH OF THE TERMINALS. WILL CARRY
MENTION OF MVFR VSBYS WITH THESE SNOW SHOWERS IN THE 18Z-21Z TIME
FRAME...BUT EXPECTING VSBYS TO REMAIN VFR AT RFD WHERE SFC DEW PTS
DEPRESSIONS HAVE NOW INCREASED TO 13 DEGREES UNDER THE INFLUENCE OF
LOW LEVEL DRY AIR ADVECTION AND MIXING. AFTER 21Z...PERHAPS A FEW
LINGERING FLURRIES BUT WILL OMIT ANY ADDITIONAL MENTION OF -SN FOR
NOW. WITH THE DRY AIR ADVECTION...CIGS HAVE INCREASED TO AOA 2K FT
AND EXPECTING CIGS TO COME UP A BIT MORE THROUGH THE REMAINDER OF
THE AFTERNOON. STRATOCU ACROSS SOUTHERN WISCONSIN WILL LIKELY
DISSIPATE SHORTLY AFTER SUNSET...AND WILL TREND TO MOSTLY CLEAR
SKIES AFT 02Z.
WINDS HAVE GENERALLY BEEN IN THE 290-310 DEGREE RANGE LATE THIS
MORNING. WIND PROFILES FROM REGIONAL ACARS SOUNDINGS INDICATING
MIXED LAYER WIND DIRECTIONS FROM 290-310 DEGREES SO EXPECTING A MORE
NORTHWESTERLY FAVORED SFC GRADIENT TO BE PARTIALLY OFFSET BY
VERTICAL MIXING HELPING TO KEEP DIRECTIONS NOT MUCH FURTHER NORTH
THAN 310 DEGREES. DID BACK OFF ON WIND GUSTS THIS AFTERNOON...WITH
ACARS WIND PROFILES/FORECAST SOUNDINGS SUGGESTING GUSTS UP TO 20
KNOTS BEFORE DIMINISHING TO AROUND 10 KNOTS TOWARD 02Z.
MARSILI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
.IL...NONE.
.IN...NONE.
.LM...SMALL CRAFT ADVISORY NEARSHORE WATERS THROUGH THIS AFTERNOON.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
303 PM CST SAT MAR 3 2007
.DAYS 1-2...
THE MAIN FORECAST CHALLENGES ARE TEMPERATURES, THEN CLOUD COVERAGE
ON MONDAY.
SHOULD BE A NICE NIGHT FOR VIEWING THE PARTIAL LUNAR ECLIPSE
TONIGHT AT MOON RISE WITH LOTS OF CLEAR SKIES AND WINDS
DECREASING. A RIDGE OF HIGH PRESSURE WILL GREATLY RELAX THE
PRESSURE GRADIENT INTO SUNDAY WITH LIGHT WINDS. AS THE UPPER LEVEL
SHORTWAVE TROUGH MOVES SOUTH A WARMER RIDGE WILL BUILD INTO THE
AREA INTO MONDAY GIVING PLENTY OF CLEAR SKIES EXCEPT FOR SOME
CIRRUS ON MONDAY. WILL KEEP TONIGHT`S LOWS IN THE MID TO UPPER
TEENS WITH LOTS OF CLEAR SKIES, LIGHT WINDS, AND LOW DEWPOINTS. ON
SUNDAY LOOK FOR A VERY NICE DAY WITH HIGHS IN THE MID TO UPPER
50S. THESE TEMPS LOOK GOOD COMPARED TO GUIDANCE.
BY MONDAY THE GFS IS FORECASTING 90 PERCENT UPPER LEVEL RH SO IF
THE CIRRUS CLOUDS ARE THICK THIS COULD HINDER THE WARM UP SOMEWHAT
ON MONDAY. THE NEW GUIDANCE FROM THE FWC SHOWS HIGHS ON MONDAY
INTO THE MID 70S BUT WITH EXPECTED CIRRUS CLOUDS I THINK THIS MAY
BE OVERDONE. WILL CONTINUE WITH THE COOLER MET GUIDANCE TEMPS IN
THE LOW TO MID 60S.
.DAYS 3-7...
THE MODELS HAVE COME INTO BETTER AGREEMENT THAT THE SYSTEM TO MOVE
THROUGH THE PLAINS LATE IN THE WEEK WILL BE ONE PROGRESSIVE WAVE
RATHER THAN SPLIT INTO 2 PIECES LIKE SOME OF THE PREVIOUS RUNS WERE
DOING. THAT SAID, THERE CONTINUES TO BE TIMING AND PRECIPITATION
INCONSISTENCIES AMONG THE VARIOUS SOLUTIONS. FAST MOVING PROGRESSIVE
WAVES ARE NOT TYPICALLY PRECIP PRODUCERS FOR THIS PART OF THE WORLD.
THE SURFACE FRONT WILL MOVE THROUGH KANSAS THURSDAY EVENING AND WILL
KEEP ANY CHANCE OF LOW LEVEL MOISTURE RETURN SHUNTED SOUTH AND EAST
OF HERE. BOTTOM LINE, THE SYSTEM LOOKS LIKE IT WILL BE MOISTURE
STARVED SO I WILL CONTINUE TO LEAVE THE FORECAST DRY.
A WEAK BOUNDARY MOVES THROUGH THE AREA ON TUESDAY WHICH SHOULD KEEP
TEMPS FROM REACHING MAX POTENTIAL. THE BOUNDARY DOESN`T RETURN NORTH
OR WASH OUT UNTIL THURSDAY. DOWNSLOPE FLOW AHEAD OF THE NEXT FRONT
THURSDAY NIGHT WILL LEAD TO A WARM DAY THURSDAY. WENT COOLER ON
FRIDAY BEHIND THE FRONT WITH A WARMING TREND STARTING ON SATURDAY AS
THE TROUGH SHIFTS EAST AND DOWNSLOPE FLOW TAKES OVER.
SEE NO REASON TO CHANGE THE 8 TO 10 DAY WITH WEST NORTHWEST
DOWNSLOPE FLOW AFFECTING THE PLAINS. SOME COOLER TEMPS MAY ARRIVE BY
AROUND DAY 10 BUT IT STILL APPEARS THAT THIS AIRMASS WILL BE OF
PACIFIC ORIGIN AND TEMPS SHOULD STILL REMAIN ABOVE AVERAGE FOR THIS
TIME OF YEAR.
&&
.AVIATION...
NORTHWEST WINDS WILL CONTINUE TO DECLINE THROUGH THE REMAINDER OF
THE AFTERNOON AND WILL BECOME LIGHT AND VARIABLE BY AROUND 8 PM.
WINDS WILL THEN BECOME MORE WESTERLY TOMORROW AT ABOUT 15KT AFTER
15Z.
THERE WILL BE NO IMPACT TO AIRCRAFT OPERATIONS AS VFR VSBYS AND
CEILINGS ARE EXPECTED TO CONTINUE FOR THE NEXT 24 HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 18 58 28 63 / 0 0 0 0
GCK 17 55 26 62 / 0 0 0 0
EHA 17 55 28 61 / 0 0 0 0
LBL 18 57 27 62 / 0 0 0 0
HYS 16 54 27 62 / 0 0 0 0
P28 21 58 30 66 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN06/27
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
911 PM EST SAT MAR 3 2007
.EVENING UPDATE...
STRONG COLD FRONT HAS EXITED EAST OF THE CWFA WITH MOST OB SITES
INDICATING GUSTY W/NW WINDS MOVING ACROSS THE REGION WITH A FEW
REPORTS TO AROUND 30 KT. THESE WINDS WILL ONLY DIMINISH PARTIALLY
OVERNIGHT GIVEN STRONG NW FLOW. UPSLOPE SNOW SHOWERS ARE EXPECTED TO
CONTINUE OUT WEST OVERNIGHT AND HAVE CONTINUED THE SNOW ADVISORY
THERE. HAVE REMOVED THE EVENING PRECIP WORDING ELSEWHERE...AND
NOTCHED THE WINDS UP ACROSS THE AREA ON MONDAY WITH A STRONG
CAA/DOWNSLOPE COMPONENT IN THE WIND FIELD AND GUSTS TO 30 MPH LIKELY.
ON THE CSTL WATERS...A TRICKY WIND FCST THROUGH MON NGT (MAINLY IN
TERMS OF HOW TO HANDLE WIND HEADLINES). PREVIOUS FCSTRS INDICATED
A POSSIBLE LULL IN THE MARINE WINDS OVERNIGHT SUNDAY. THIS SEEMS
LIKE A GOOD BET OVER MOST OF THE WATERS...THEREFORE HAVE TWEAKED THE
WIND WORDING SUN NIGHT TO REFLECT A LULL IN THE SCA LEVEL WINDS
AFTER MIDNIGHT. WINDS ON MON HWVR LOOK QUITE STRONG WITH NEAR GALES
POSSIBLE (18Z GFS SOUNDINGS SHOW NEAR 50 KT AT THE TOP OF WELL MIXED
LYR). HAVE CONTINUED TO MENTION SCA CONDS LIKELY MON AND MON NGT.
LATER SHIFT WILL LIKELY NEED TO EXTEND THE CURRENT HEADLINE INTO
MONDAY BUT SINCE THAT WOULD BE THE CURRENT 4TH PERIOD...HAVE KEPT
LATEST HEADLINES INTACT.
JB
&&
.PREVIOUS DISCUSSIONS...
SHORT TERM /TONIGHT THROUGH SUNDAY/...
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.
THE 1705Z DESCENT KIAD ACARS SOUNDING INDICATES 4C OF COOLING
BETWEEN 700-500MB SINCE THE 12Z KIAD RAOB. THIS IS IN ASSOCIATION
WITH THE FIRST DECAYING WAVE ALOFT WHICH BROUGHT LIGHT SHOWERS
ACROSS NORTH CENTRAL MARYLAND. IT IS TAKING SEVERAL HOURS TO MIX OUT
SHALLOW COLD POOL BEHIND THE DISSIPATING COLD FRONT STRETCHED
SOUTHWEST TO NORTHEAST...BISECTING THE FORECAST AREA.
THE NEXT COLD FRONT IS MOVING THROUGH WEST VIRGINIA...WITH INCREASED
SHOWER RETURNS EVIDENT AS DESTABILIZATION (FROM THE SURFACE AND
ALOFT) TAKE PLACE. THIS WILL PRESENT A WINDOW OF OPPORTUNITY FOR
SHOWERS AND THUNDERSTORMS TO DEVELOP LATE THIS AFTERNOON AND EARLY
THIS EVENING. 12Z NAM/GFS INDICATE 100-200 J/KG OF INSTABILITY
DURING THE LATE 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.
MEANWHILE...COLD ADVECTION WILL BE TAKING PLACE ACROSS THE
MOUNTAINS...WHERE SYNOPTIC CYCLONIC FLOW WILL OCCUR ATOP MOIST
UPSLOPE. 12Z NAM/GFS INDICATE THE MOISTURE DEPTH IS FAIRLY DEEP
(6 KFT)...WITH A GOOD UPSLOPE TRAJECTORY OVERNIGHT. THERE IS A
CLUSTERING AT ABOUT 0.4" LIQUID EQUIVALENT QPF FROM THE 09Z SHORT
RANGE ENSEMBLE MEMBERS AT KEKN THROUGH MID MORNING SUNDAY. GIVEN A
DECENT FLOW ATOP THE BOUNDARY AND THE TROUGH PASSING OVERHEAD...WILL
HAVE SNOW SHOWERS MENTIONED TO THE BLUE RIDGE AND SOME FLURRIES EAST
TO THE INTERSTATE 95 CORRIDOR.
PROXIMITY TO THE MID LEVEL TROUGH ALOFT WILL KEEP CLOUDS ACROSS THE
REGION SUNDAY. ANY CLEAR PATCHES WHICH DEVELOP LATER TONIGHT WILL
FILL IN AS THE BOUNDARY LAYER MIXES DURING THE MORNING. UPSLOPE
MOUNTAIN SNOW SHOWERS WILL BE DECAYING THROUGH THE DAY.
LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
AVIATION...
SHOWER AND THUNDERSTORM ACTIVITY WILL DEVELOP DURING THE MID TO LATE
AFTERNOON WITH THE ARRIVAL OF THE NEXT SECONDARY COLD FRONT AND WAVE
ALOFT. WINDS WILL SHIFT TO THE NORTHWEST WITH GUSTS CONTINUING
ACROSS MOST TAF SITES INTO SUNDAY.
MARINE...
12Z ETA/GFS MOS AT THOMAS POINT INDICATE SUSTAINED WINDS WILL
INCREASE FROM 15KT TONIGHT TO 20KT SUNDAY. 12Z NAM/GFS PROXIMITY
FORECAST SOUNDINGS INDICATE WIND GUST POTENTIAL OF 25-30 KNOTS
THROUGH SUNDAY.
HYDROLOGY...
MAIN STEM FORECAST POINTS ARE ALL UNDER FLOOD STAGE.
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 FALL TO NEAR ASTRONOMICAL PREDICTIONS TONIGHT.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...SNOW ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST SUNDAY FOR
MDZ501.
VA...SNOW ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST SUNDAY FOR
VAZ021.
WV...SNOW ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST SUNDAY FOR
WVZ054-501-503.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST SUNDAY FOR ANZ530>537.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
315 PM EST SAT MAR 3 2007
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
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.
THE 1705Z DESCENT KIAD ACARS SOUNDING INDICATES 4C OF COOLING
BETWEEN 700-500MB SINCE THE 12Z KIAD RAOB. THIS IS IN ASSOCIATION
WITH THE FIRST DECAYING WAVE ALOFT WHICH BROUGHT LIGHT SHOWERS
ACROSS NORTH CENTRAL MARYLAND. IT IS TAKING SEVERAL HOURS TO MIX OUT
SHALLOW COLD POOL BEHIND THE DISSIPATING COLD FRONT STRETCHED
SOUTHWEST TO NORTHEAST...BISECTING THE FORECAST AREA.
THE NEXT COLD FRONT IS MOVING THROUGH WEST VIRGINIA...WITH INCREASED
SHOWER RETURNS EVIDENT AS DESTABILIZATION (FROM THE SURFACE AND
ALOFT) TAKE PLACE. THIS WILL PRESENT A WINDOW OF OPPORTUNITY FOR
SHOWERS AND THUNDERSTORMS TO DEVELOP LATE THIS AFTERNOON AND EARLY
THIS EVENING. 12Z NAM/GFS INDICATE 100-200 J/KG OF INSTABILITY
DURING THE LATE 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.
MEANWHILE...COLD ADVECTION WILL BE TAKING PLACE ACROSS THE
MOUNTAINS...WHERE SYNOPTIC CYCLONIC FLOW WILL OCCUR ATOP MOIST
UPSLOPE. 12Z NAM/GFS INDICATE THE MOISTURE DEPTH IS FAIRLY DEEP
(6 KFT)...WITH A GOOD UPSLOPE TRAJECTORY OVERNIGHT. THERE IS A
CLUSTERING AT ABOUT 0.4" LIQUID EQUIVALENT QPF FROM THE 09Z SHORT
RANGE ENSEMBLE MEMBERS AT KEKN THROUGH MID MORNING SUNDAY. GIVEN A
DECENT FLOW ATOP THE BOUNDARY AND THE TROUGH PASSING OVERHEAD...WILL
HAVE SNOW SHOWERS MENTIONED TO THE BLUE RIDGE AND SOME FLURRIES EAST
TO THE INTERSTATE 95 CORRIDOR.
PROXIMITY TO THE MID LEVEL TROUGH ALOFT WILL KEEP CLOUDS ACROSS THE
REGION SUNDAY. ANY CLEAR PATCHES WHICH DEVELOP LATER TONIGHT WILL
FILL IN AS THE BOUNDARY LAYER MIXES DURING THE MORNING. UPSLOPE
MOUNTAIN SNOW SHOWERS WILL BE DECAYING THROUGH THE DAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
&&
.AVIATION...
SHOWER AND THUNDERSTORM ACTIVITY WILL DEVELOP DURING THE MID TO LATE
AFTERNOON WITH THE ARRIVAL OF THE NEXT SECONDARY COLD FRONT AND WAVE
ALOFT. WINDS WILL SHIFT TO THE NORTHWEST WITH GUSTS CONTINUING
ACROSS MOST TAF SITES INTO SUNDAY.
&&
.MARINE...
12Z ETA/GFS MOS AT THOMAS POINT INDICATE SUSTAINED WINDS WILL
INCREASE FROM 15KT TONIGHT TO 20KT SUNDAY. 12Z NAM/GFS PROXIMITY
FORECAST SOUNDINGS INDICATE WIND GUST POTENTIAL OF 25-30 KNOTS
THROUGH SUNDAY.
&&
.HYDROLOGY...
MAIN STEM FORECAST POINTS ARE ALL UNDER FLOOD STAGE.
&&
.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 FALL TO NEAR ASTRONOMICAL PREDICTIONS TONIGHT.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...SNOW ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST SUNDAY FOR
MDZ501.
VA...SNOW ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST SUNDAY FOR
VAZ021.
WV...SNOW ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST SUNDAY FOR
WVZ054-501-503.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST SUNDAY FOR ANZ530>537.
&&
$$
SHORT TERM/AVIATION/HYDROLOGY/TIDES...ROGOWSKI
LONG TERM...LISTEMAA
MARINE...ROGOWSKI/LISTEMAA
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1015 AM EST FRI MAR 2 2007
.SHORT TERM...
WATER VAPOR LOOP SHOWS AN UPPER LOW SPINNING OVER THE MIDWEST...WITH
A DRY INTRUSION PROGRESSING NORTHEAST THROUGH THE APPALACHIANS AND
EASTERN GREAT LAKES. ACARS 400-250MB WIND OBSERVATIONS REVEAL A
150-190KT WESTERLY JET ACROSS THE SOUTHERN CONUS...WHICH CURLS
NORTHEAST THROUGH THE MID ATLANTIC. 11Z SURFACE ANALYSIS PLACED A
979MB OCCLUDED CYCLONE ACROSS CENTRAL WISCONSIN. THE OCCLUDED/COLD
FRONT EXTENDED FROM THE CYCLONE EAST ACROSS THE EASTERN GREAT
LAKES...THEN SOUTH THROUGH THE EASTERN PORTION OF THE CAROLINAS AND
SOUTHWEST INTO THE CENTRAL GULF OF MEXICO. A WARM FRONT EXTENDED
NORTHEAST FROM MANASSAS TOWARD LONG ISLAND. SEVERAL SECONDARY COLD
FRONTS STRETCH SOUTHWEST AND WEST FROM THE OCCLUDED CYCLONE ACROSS
THE CENTRAL CONUS. A TROUGH WAS NOTED IN THE LEE OF THE APPALACHIANS.
THE COLD FRONT HAS JUST REACHED THE WESTERN SHORELINE OF THE
CHESAPEAKE BAY. SIGNIFICANT SUBSIDENCE ON THE SYNOPTIC SCALE EVIDENT
FROM WATER VAPOR IMAGERY WILL LEAD TO SUNNY SKIES THIS AFTERNOON.
GRADIENT WILL STILL ALLOW FOR 25 MPH WIND GUSTS INTO THE EARLY
AFTERNOON JUDGING FROM THE 12Z KIAD RAOB AND MORNING ACARS
SOUNDINGS. GIVEN WARM MORNING READINGS...FURTHER MIXING WILL YIELD
HIGHS NEAR 60F IN MANY LOCATIONS. LOWER 40S EXPECTED IN THE HIGHER
TERRAIN WITH COLD ADVECTION THIS AFTERNOON.
&&
.AVIATION...
CEILING AND VISIBILITY RESTRICTIONS WILL CONTINUE TO IMPROVE TO VFR
WITH THE COLD FRONTAL PASSAGE. MIXING WILL ENCOURAGE 25KT WIND GUSTS
THROUGH THE AFTERNOON.
&&
.MARINE...
00Z ETA/06 GFS MOS AT THOMAS POINT INDICATE SUSTAINED WINDS WILL
FALL INTO THE 15-20KT RANGE BY MIDDAY. 12Z NAM/06Z GFS PROXIMITY
FORECAST SOUNDINGS INDICATE WIND GUST POTENTIAL OF 25-30 KNOTS
THROUGH THE AFTERNOON.
&&
.TIDES...
CURRENT TIDAL DEPARTURES ARE ONE AND A HALF TO TWO AND A HALF FEET
ABOVE ASTRONOMICAL PREDICTIONS. THE LUNAR CYCLE IS NEAR A FULL MOON
(98 PERCENT FULL). THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM
INDICATES WATER LEVELS WILL RECEDE TO WITHIN A HALF FOOT OF
ASTRONOMICAL PREDICTIONS DURING THE EVENING.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR
ANZ530>537.
&&
$$
SHORT TERM/AVIATION/MARINE/TIDES...ROGOWSKI
|