AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
AFDSGX 330 AM PST THU JAN 4 2007
.SYNOPSIS...AN APPROACHING PACIFIC WEATHER SYSTEM WILL BRING
VARIABLE CLOUDINESS TODAY WITH A CHANCE OF SHOWERS TONIGHT. LOCALLY
WINDY IN THE MOUNTAINS...DESERTS AND COASTAL WATERS WITH THIS
SYSTEM. DRY OFFSHORE FLOW WILL DEVELOP FRIDAY FOR CLEARING SKIES AND
LOCAL STRONG GUSTY WINDS THROUGH AND BELOW MOUNTAIN CANYONS AND
PASSES...SLOWLY DECREASING THROUGH THE WEEKEND. WARMER DAYS THIS
WEEKEND. HIGH PRESSURE AND WEAK OFFSHORE FLOW WILL MAINTAIN FAIR
WEATHER THROUGH THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.SHORT TERM (TODAY-SATURDAY)...THERE WAS A WEAK EDDY WITH LOW CLOUDS
AND FOG IN THE COASTAL AREAS AND LOCALLY INTO THE WRN INLAND VALLEYS
THIS MORNING. THERE WERE ALSO PATCHES OF DENSE FOG. CLEAR ELSEWHERE.
EARLY MORNING ACARS SOUNDINGS HAD AN INVERSION BASED NEAR 1200 FT
WITH STRONG NW WINDS ALOFT. INCREASING ONSHORE GRADIENTS WITH ABOUT
4 MB SAN-IPL.
THE MARINE LAYER WILL CONTINUE TO AFFECT THE COASTAL AREAS AND WRN
VALLEYS THIS MORNING WITH LITTLE TIME TO CLEAR BEFORE STARTING TO
INCREASE AGAIN THIS AFTERNOON. HIGH CLOUDS WILL ALSO INCREASE TODAY
FROM AN UPPER TROUGH OF LOW PRESSURE APPROACHING FROM THE NW. THE
TROUGH WILL MOVE THROUGH TONIGHT BRINGING A CHANCE OF SHOWERS. THE
TROUGH WILL BE FAIRLY VIGOROUS WITH AN ASSOCIATED COLD FRONT THAT
WILL MOVE THROUGH RAPIDLY TONIGHT. MOST OF THE PRECIP WILL BE WITH
THE COLD FRONTAL PASSAGE. RAINFALL AMOUNTS SHOULD BE ABOUT ONE TENTH
TO ONE QUARTER INCH...WITH LOCALLY HIGHER AMOUNTS ON W FACING
MOUNTAIN SLOPES. THE SNOW LEVELS WILL START ABOVE 7000 FT AND WILL
RAPIDLY LOWER TO 4000-5000 FT LATE TONIGHT. HOWEVER...MOST OF THE
MOISTURE WILL REMAIN BELOW THE SNOW LEVEL SO LOCAL SNOW AMOUNTS
SHOULD GENERALLY BE IN THE 1-2 INCH RANGE. GUSTY WINDS WILL
ACCOMPANY THIS SYSTEM...MAINLY IN THE MOUNTAINS...DESERTS AND
COASTAL WATERS. OFFSHORE FLOW WILL DEVELOP BEHIND THE SYSTEM FOR
RAPID DRYING. THERE WILL BE LOCAL STRONG GUSTY WINDS THROUGH AND
BELOW MOUNTAIN CANYONS AND PASSES...ESPECIALLY BELOW THE CAJON PASS
AND IN THE SANTA ANA MOUNTAINS FRI. WEAKER OFFSHORE FLOW WILL
CONTINUE THROUGH SAT. WARMER SAT...ESPECIALLY W OF THE MOUNTAINS.
.LONG TERM (SUNDAY-WEDNESDAY)...HIGH PRESSURE ALOFT AND WEAK
OFFSHORE FLOW WILL MAINTAIN FAIR WEATHER WITH WARMER DAYS SUN AND
MON. A LITTLE COOLER TUE AND WED AS HEIGHTS DECREASE AND ONSHORE
FLOW DEVELOPS. ANOTHER TROUGH COULD BRING A CHANCE OF SHOWERS TOWARD
NEXT THU.
&&
.AVIATION...
ONSHORE FLOW AND A WEAK COASTAL EDDY IS BRINGING MARINE LAYER
STRATUS AND FOG TO THE COASTAL AREAS OF SOUTHERN CALIFORNIA. AT 2
AM...THE STRATUS IS FILLING IN OVER THE COASTAL AREAS AND MOVING
INLAND WITH BASES MOSTLY AROUND 1000 FEET MSL AND TOPS AROUND 1600
FEET. EXPECT SOME LIFTING OF THE BASES TO AROUND 1500 FEET DURING
THE NIGHT WITH TOPS RISING TO AROUND 2000 FEET AS THE MARINE LAYER
DEEPENS FURTHER. STRATUS IS EXPECTED TO REACH THE INLAND EMPIRE AREA
NEAR KONT BEFORE SUNRISE. THE STRATUS SHOULD BREAK UP DURING THE MID
TO LATE MORNING HOURS ON THURSDAY. CLOUDS AHEAD OF AN APPROACHING
COLD FRONT SHOULD BEGIN TO SPREAD OVER THE AREA DURING THE AFTERNOON
ON THURSDAY. THESE CLOUDS SHOULD BE ABOVE 12000 FEET INITIALLY THEN
LOWER TO AROUND 5000 FEET BY LATE AFTERNOON OR EARLY EVENING.
MOUNTAINS AND DESERT AREAS SHOULD REMAIN VFR WITH A MOSTLY CLEAR SKY.
&&
.MARINE...
A VIGOROUS COLD FRONT WILL BRING LARGE SWELL AND GALE FORCE WINDS
THU EVENING THROUGH FRI. THE COMBINATION OF THESE FEATURES WILL
PRODUCE HAZARDOUS SEAS FOR MARINERS...SEE LAXMWSSGX...AND LARGE SURF
FOR BEACH VISITORS...SEE LAXCFWSGX. SEAS AND WINDS WILL SLOWLY
DECREASE FRI.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FRI...FOR SAN BERNARDINO COUNTY MOUNTAINS...INLAND
EMPIRE AND SANTA ANA MOUNTAINS...SEE LAXNPWSGX.
FIRE WEATHER WATCH FRI THROUGH SAT...FOR MOUNTAINS AND VALLEYS...SEE
LAXRFWSGX.
SPECIAL WEATHER STATEMENT FOR THE COLD FRONT AND GUSTY WINDS...SEE
LAXSPSSGX.
HIGH SURF ADVISORY FROM 4 PM TODAY TO 10 PM PST FRI...FOR ORANGE
COUNTY AND SAN DIEGO COUNTY COASTS...SEE LAXCFWSGX.
SMALL CRAFT ADVISORIES FOR THE INNER AND OUTER WATERS TONIGHT AND
FRI FOR WINDS AND HAZARDOUS SEAS AND GALE WARNING FOR OUTER
WATERS TONIGHT...SEE LAXCWFSGX.
&&
$$
PUBLIC...DVA
AVIATION/MARINE...PG
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
AFDLMK 1039 AM EST THU JAN 4 2007
.MORNING UPDATE...
OVERALL FORECAST IS IN GOOD SHAPE...MODELS ARE NOT HANDLING THE
COMPLEX JET PATTERN ACROSS THE MS AND OH VALLEYS VERY WELL AND ARE
MISSING THE MAJORITY OF THE PRECIP ACROSS IL INTO SOUTHERN IN AND
FAR NORTHERN KY. HAVE ADDED A SMALL CHC POP THERE TO ACCOUNT FOR
THE LIGHT RAIN AND SPRINKLES THAT WILL CONTINUE SCATTERED ABOUT
THE REGION.
TEMPS ARE PUSHING TOWARDS 50 ALREADY AS OF 10 AM...SLIGHTLY WARMER
ACROSS THE EASTERN AND SOUTHEASTERN ZONES WHERE LESS CLOUD COVER
HAS ALLOWED FOR GREATER HEATING...LOW 60S WILL BE POSSIBLE
ACROSSMUCH OF THE AREA ESPECIALLY THE DALE HOLLOW AND CUMBERLAND
LAKE AREA...WITH UPPER 50S TO AROUND 60 POSSIBLE IN THE BLUEGRASS
REGION OF EAST CENTRAL KY AND EAST TOWARDS THE LOUISVILLE METRO. MID
AND UPPER LEVEL CLOUDS WILL EVENTUALLY OVERTAKE THE ENTIRE REGION
BY LATE THIS AFTERNOON IF NOT BY MID AFTERNOON...WITH THE LOWER
CU/SC JUST NOW APPROACHING THE REGION FROM THE SOUTHWEST. HAVE
MADE SOME TWEAKS TO THE DEWPOINTS UPWARDS SOME AS THE REGION
DOWNSTREAM OF US SHOWS UPPER 40S AND LOWER 50S...SHOULD SEE STEADY
CLIMB AS THE DAY PROGRESSES. DISCUSSION ABOUT POSSIBLE HEAVY RAIN
REMAINS BELOW...VERY LITTLE IN THIS RESPECT HAS CHANGED.
SCHOTT
&&
.AVIATION...
WANTED TO MENTION A FEW THINGS IN REGARDS TO THE AVIATION
INTERESTS...HAVE ADDED LOW LEVEL WIND SHEAR TO THE ENTIRE
TAF...CURRENT ACARS SOUNDING INCOMING TO SDF HAVE SHOWN
STRENGTHENING WINDS AROUND 1500 FEET TO AROUND OR SLIGHTLY ABOVE
30 KTS...WELL WITHIN THE CRITERIA OF NON-CONVECTIVE LLWS. THIS
STRONG LOW LEVEL JET WILL CONTINUE THROUGH THE NIGHT WHILE
STRENGTHEN AS PER THE LATEST BUFKIT SOUNDING TO AROUND 35KTS BY
00-01Z. A SMALL AREA OF LOW LEVEL CEILINGS AROUND 1-1.5K FT HAS
WORKED INTO THE SOUTHWESTERN AREA NEAR BWG...AND CONTINUES A SLOW
CRAWL TO THE NORTH. WILL UPDATE BWG TAF FOR THIS FEATURE.
SCHOTT
&&
.PREV DISCUSSION... /ISSUED 247 AM EST THU JAN 4 2007/
SHORT TERM (TODAY AND TONIGHT)...
..HEAVY RAIN TONIGHT...
UPPER LOW TO MOVE FROM THE BIG BEND REGION OF TEXAS THIS MORNING TO
THE LOWER MISSISSIPPI VALLEY BY 12Z FRIDAY. MEANWHILE A WEAK SURFACE
LOW WILL TRAVEL FROM SOUTHEAST TEXAS TO NEAR LOUISVILLE.
DEEP MOISTURE WILL STREAM NORTHWARD AHEAD OF THIS SYSTEM AND WILL
REACH WESTERN PORTIONS OF THE LOUISVILLE CWFA BY 00Z THIS EVENING.
DRY LAYER AROUND 850HPA WILL GRADUALLY SATURATE BETWEEN 00Z AND
03Z. THE HEAVIEST STEADIEST RAIN IS EXPECTED TO OCCUR BETWEEN
MIDNIGHT AND DAWN.
INSTABILITY PARAMETERS AND LAPSE RATES SUGGEST ANY THUNDER WOULD BE
ISOLATED. HOWEVER 60 KNOT LOW LEVEL JET DOES CRANK UP AFTER MIDNIGHT
FROM TENNESSEE TO OHIO...WHICH WILL ASSIST IN PULLING MOISTURE INTO
THE REGION.
MANY SIGNS POINT TO HEAVY RAIN TONIGHT. K INDEX WILL RISE INTO THE
MIDDLE 30S. PRECIPITABLE WATER VALUES WILL PEAK AROUND 1.6
INCHES...WHICH IS ABOUT THREE STANDARD DEVIATIONS ABOVE NORMAL FOR
EARLY JANUARY...QUITE IMPRESSIVE. POSITIVE ADVECTION OF RICH
THETA-E AIR IS FORECAST AS WELL. LOOKING AT THE CURRENT WATER VAPOR
SATELLITE LOOP A HEALTHY TROPICAL MOISTURE PLUME CAN BE EASILY SEEN
FROM THE EASTERN PACIFIC OCEAN ACROSS MEXICO INTO THE EASTERN UNITED
STATES. GIVEN ALL THIS...RAINFALL AMOUNTS AROUND AN INCH SHOULD BE
COMMONPLACE TONIGHT...ESPECIALLY ALONG AND SOUTH OF THE OHIO RIVER.
HIGH TEMPERATURES TODAY SHOULD BE SIMILAR TO YESTERDAY...MAYBE A
COUPLE OF DEGREES WARMER DEPENDING ON HOW MUCH MID AND HIGH
CLOUDINESS STREAMS IN AND HOW THICK IT IS. WITH CLOUDS...RAIN...AND
SOUTHERLY FLOW TONIGHT TEMPERATURES WON/T FALL MORE THAN FIVE TO TEN
DEGREES.
13
LONG TERM (FRIDAY THROUGH WEDNESDAY)...
FRIDAY THROUGH MONDAY NIGHT...
00Z MODELS ARE IN GOOD AGREEMENT TONIGHT WITH MAIN WEATHER SYSTEM
THAT WILL BE AFFECTING THE AREA MAINLY ON FRIDAY. NOT TOO MUCH
CHANGE TO THE PREVIOUS FORECAST AS MODEL CONTINUITY REMAINS GOOD.
SFC LOW PRESSURE SYSTEM FORECAST TO BE PASSING THROUGH THE REGION AT
THE BEGINNING OF THE PD WITH CLOUDS AND WIDESPREAD RAINS. HAVE
INCREASED POPS FRIDAY MORNING AND MAINTAINED THUNDER IN THE MORNING
AS LOW-LEVEL JET AND SOME ELEVATED INSTABILITY WILL BE IN THE AREA.
PRECIPITATION WILL LIKELY DIMINISH AND BECOME MORE SCT IN NATURE
FRIDAY EVENING. SECONDARY UPPER TROF AND ASSOCIATED SFC FRONT STILL
LOOK TO MAKE A PUSH THROUGH REGION ON SATURDAY. HAVE MAINTAINED
POPS THROUGH SATURDAY NIGHT. TEMPERATURES WILL BE VERY MILD ON
FRIDAY WITH HIGHS IN THE LOW TO MID 60S EARLY IN THE DAY BEFORE SFC
SYSTEM MOVES THROUGH THE REGION. TEMPS STILL LOOK TO BE JUST UNDER
RECORD HIGHS. SLIGHTLY COOLER TEMPS WILL BE NOTED ON SATURDAY AS
UPPER LEVEL TROF SWINGS THROUGH. GENERALLY KEPT TEMPS IN THE LOW TO
MID 50S NORTH AND MID 50S IN THE SOUTH.
NEXT WEATHER SYSTEM WILL APPROACH FROM THE SOUTHWEST DURING THE DAY
ON SUNDAY. LATEST TRENDS IN THE MODEL SOLUTIONS SHOW A FAIRLY
DECENT GRADIENT IN POPS ACROSS THE DISTRICT ON SUNDAY. WITH OUR
AREA ON THE NORTHWESTERN FRINGES...ONLY SLIGHT CHC POPS WILL BE
NOTED ACROSS SOUTHERN INDIANA WITH BEST CHANCES OF PRECIP MAINLY
ACROSS OUR SOUTHEASTERN COUNTIES...MAINLY SE OF A LINE FROM LEX TO
BWG. FOR THIS FORECAST...WE HAVE INCREASED POP CHANCES ACROSS THIS
REGION UP TO 50 PERCENT FOR SUNDAY AFTERNOON. PRECIPITATION SHOULD
QUICKLY DIMINISH SUNDAY NIGHT AS SYSTEM PULLS OFF TO THE EAST.
SKIES SHOULD BEGIN TO CLEAR OUT WITH PARTLY SUNNY SKIES FOR MONDAY.
WITH THE NEXT UPPER TROF PUSHING IN AND 850 TEMPS FALLING TO AROUND
-6 TO -8...TEMPS ON MONDAY WILL BE SEASONAL.
TUESDAY THROUGH WEDNESDAY...
NO CHANGES MADE THROUGH THIS PERIOD OF THE FORECAST. LATEST 00Z
RUNS TONIGHT CONTINUE TO ADVERTISE A DRY PERIOD FOR TUESDAY AND
WEDNESDAY AS SOUTHEASTERN RIDGE HOLDS STRONG. AREA OF SURFACE HIGH
PRESSURE WILL DRIFT ACROSS THE REGION ON TUESDAY AND WILL BE
ANCHORED OFF THE EASTERN U.S. COAST BY WEDNESDAY NIGHT. SOUTHERLY
FLOW WILL RETURN TO THE OHIO VALLEY ON WEDNESDAY WITH A SLIGHT
MODERATION IN TEMPERATURES.
PREVIOUS DISCUSSION ON THE LONGER TERM FORECAST CONTINUES TO LOOK
GOOD. EXTENDED RANGE MODELS CONTINUE TO SHOW BERING STRAIT CUT OFF
LOW OPENING UP AND BEING REPLACED BY DECENT UPPER LEVEL RIDGE.
RESULTING DOWNSTREAM TROF IS FORECAST TO DEVELOP ACROSS THE WESTERN
CONUS AND HELP SET UP POSSIBLE CROSS POLAR FLOW ALLOWING A RETURN OF
ARCTIC AIR ACROSS CANADA. WHILE COLD AIR WILL LIKELY INVADE THE
WESTERN HALF OF THE COUNTRY...MAIN FEATURE KEEPING IT OUT OF THE
EAST WILL BE THE STUBBORN SE RIDGE. THOUGH WITH THE OP GFS TENDING
TO BE TOO DEEP WITH THE WESTERN TROF...DOWNSTREAM SE RIDGE IS
PROBABLY A BIT OVERDONE. STILL QUITE A BIT OF MODEL UNCERTAINTY
AT THIS TIME RANGE...BUT THE ARRIVAL OF A MODIFIED POLAR AIRMASS MAY
AFFECT THE OHIO VALLEY AFTER MID-MONTH.
-MJ
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
AFDAPX 1002 PM EST FRI JAN 5 2007
.UPDATE...AREA RADARS SHOW NARROW WELL-DEFINED FRONTOGENETICALLY
DRIVEN PRECIPITATION BAND ACROSS CENTRAL WI/EASTERN IA MAKING STEADY
PROGRESS EAST. COLD FRONT REPRESENTING LEADING EDGE OF BAROCLINIC
ZONE HAS MOVED INTO LAKE HURON...FRONTAL SURFACE AT 850MB MOVING
INTO LOWER MI AT MID EVENING. PRECIPITATION BAND LINES UP WITH
STRONGEST FRONTOGENETIC RESPONSE IN THE 700-500MB LAYER (WHERE
BETTER MOISTURE HAPPENS TO BE AS WELL)...AND IN LFQ OF 150KT JET
STREAK PUNCHING ACROSS KS/NORTHERN MO/SOUTHERN IA. SOME MID LEVEL
RADAR RETURNS HAVE BEEN DEVELOPING ACROSS NORTHERN LAKE MICHIGAN...
00Z APX SOUNDING STILL PRETTY DRY BELOW 500MB (5-10C DEW POINT
DEPRESSIONS IN GENERAL)...GRB SOUNDING UPSTREAM SHOWING HIGHER RH
DOWN TO 700MB...RECENT AIRCRAFT SOUNDING OUT OF ATW SATURATED DOWN
TO AROUND 725MB WITH A WEDGE OF DRY AIR BELOW. SO AS MAIN PRECIP
BAND APPROACHES WILL TAKE A LITTLE TIME TO SATURATE LOWER LAYERS TO
ALLOW PRECIP TO REACH THE GROUND. NORTHERN EDGE OF PRECIP BAND
SHOULD BEGIN TO PUSH INTO FAR NORTHWEST LOWER AROUND MIDNIGHT OR
SO...AND GRADUALLY WORK ITS WAY EAST ACROSS THE FORECAST AREA AS THE
NIGHT WEARS ON...LIKELY NOT REACHING AREAS AROUND SAGINAW BAY UNTIL
AFTER 09Z. AS FOR PRECIP TYPE...APX SOUNDING FREEZING LEVEL AROUND
7K FEET...WET BULB FREEZING LEVEL CLOSER TO 3K FEET. SURFACE
TEMPERATURES STILL IN THE UPPER 30S/AROUND 40 FOR THE MOST PART...
SO WILL PROBABLY START OFF AS RAIN EXCEPT PERHAPS AROUND THE STRAITS
AREA. COLDER AIR WILL CONTINUE TO FILTER IN AS THE NIGHT WEARS ON
AND 850MB FRONT MOVES THROUGH THE FORECAST AREA...SO MAY START TO
SEE A MIX ACROSS NORTHWEST LOWER OR AN OUTRIGHT CHANGE TO SNOW
ACROSS THE INTERIOR HIGHER TERRAIN LATE...SAY AFTER 08-09Z OR
SO.
JPB
&&
.PREV DISCUSSION...336 PM EST FRI JAN 5.
500 MB WIND SPEED MAX MOVING THROUGH LAKE SUPERIOR AND A SECOND ONE
MOVING UP FROM KANSAS. THERE IS SOME WEAK COUPLING WITH A BAND OF
F-GEN PRECIPITATION IN NW IOWA TO CENTRAL WISCONSIN. THERE IS A DRY
SLOT THAT OVER LAKE MICHIGAN, HOWEVER, CLOUDS ARE FORMING ALONG THE
SHORELINE AND KEEPING THE FORECAST AREA CLOUDY.
MODELS HAVE FEW DIFFERENCES OVER THE FORECAST AREA THROUGH THE 84
HOURS OF THE MAIN FORECAST PACKAGE.
TONIGHT...CLOUD COVER THAT HAS CONTINUED TO DEVELOP OFF OF LAKE
MICHIGAN WILL CONTINUE AS THE F-GEN AREA MOVES INTO THE REGION. OUT
OF THE NAM AND GFS, THE GFS ACTUALLY HAS HAD THIS FGEN BAND IN ITS
QPF. OTHERWISE, THE MODELS CONTINUE TO SHOW THE SAME BASIC PATTERN.
SO FOR TONIGHT, THE PRECIPITATION MOVES INTO THE FORECAST REGION.
THE PRECIPITATION WON`T BE HEAVY, BUT IT LOOKS LIKELY OVER MOST OF
THE FORECAST AREA THAT THERE WILL BE MEASURABLE PRECIPITATION. THE
MODEL SOUNDINGS WOULD SUGGEST THAT IN THE HIGHER ELEVATIONS INLAND,
WILL START OFF MIXED. OVERNIGHT, THE 850 TEMPERATURES BEGIN TO FALL
BELOW ZERO C AND THE MODEL SOUNDINGS ARE MORE CONDUCIVE FOR SNOW IN
THE HIGHLANDS WHILE MOST AREAS, ESPECIALLY ALONG THE SHORELINES WILL
CONTINUE TO SEE RAIN.
SATURDAY...BY 12Z, THE SOUNDINGS LOOK COLD ENOUGH FOR SNOW, FOR
LARGER PORTIONS OF THE FORECAST AREA, HOWEVER, THE SOUNDINGS BEGIN
TO DRY OUT, WHICH IS EXPECTED TO CUT THE SNOW DOWN TO FLURRIES OVER
MOST OF THE REGION, AT THE LEAST. LOOKING AT THE 850-700 MB LAYER
RH, BOTH MODELS SUGGEST THAT THERE WILL BE 40% OR LESS AND THE
1000-850 MB FLOW TURNS MORE ANTICYCLONIC. SO WON`T BE SURPRISED IF
NOTHING HAPPENS DURING THE AFTERNOON.
LUTZ
LONGER TERM...SATURDAY NIGHT THROUGH THURSDAY...BRIEF SHOT OF COLDER
AIR (-8C AT H8) FOR POSSIBLE LIGHT LAKE EFFECT SNOW SHOWERS/FLURRIES
EARLY SATURDAY NIGHT. HOWEVER...ANY CHANCE FOR THIS WILL EXIT
OVERNIGHT AS AIR MASS MODIFIES/WARMS AHEAD OF NEXT SHORTWAVE
TROUGH...WHICH SHARPENS OUT THE LONGWAVE TROUGH...WHICH IN TURN...
AMPLIFIES AND CARVE ITSELF INTO THE EASTERN HALF OF THE COUNTRY.
THIS FEATURE WILL ESSENTIALLY BE THE IMPETUS FOR OUR FIST LOOK AT
LAKE EFFECT SNOW SHOWERS FOR 2007. THIS SHORTWAVE WILL PROVIDE A
CHANCE FOR SNOW...POSSIBLY MIXED WITH A TOUCH OF RAIN ALONG THE
SHORE OF LAKE MICHIGAN...LATE SUNDAY AFTERNOON AND INTO SUNDAY
NIGHT. COLD AIR THEN BEGINS TO POUR INTO NRN MICHIGAN. AIR THAT
WOULD BE CLOSER TO NORMAL FOR US...AND ALTHOUGH THERE MAY BE SOME
MOISTURE QUESTIONS THAT NEED TO BE ADDRESSED...THE CHANCE FOR LAKE
EFFECT SNOW SHOWERS ARRIVES. MOISTURE AVAILABILITY REMAINS A CONCERN
THROUGH MONDAY... BUT AS ADDITIONAL SHORTWAVE ENERGY DRIVES DOWN THE
NW FLOW ALOFT TUESDAY AND TUESDAY NIGHT...DEEPER MOISTURE...NICE
CYCLONIC FLOW AND EVEN COLDER H8 AIR (-16C NOW) ARRIVES. THIS WILL
RESULT IN OUR BEST SHOT OF LAKE EFFECT SNOW...WITH
ACCUMULATION...PROVIDING THE PATTERN HOLDS. TROUGHING DIGS INTO THE
WEST COAST AGAIN BY LATE NEXT WORK WEEK AND WARMING RETURNS TO NRN
MICHIGAN...THE DEGREE OF WHICH REMAINS UNCERTAIN. IT WILL BE VERY
HARD TO MODIFY THE COLD AIR THAT WE DO GET...BACK TO THE KIND OF
TEMPERATURES WE HAVE BEEN SEEING OVER THE LAST SEVERAL DAYS HOWEVER.
SATURDAY NIGHT...AM KEEPING THINGS PRECIPITATION FREE ACROSS THE
REGION...AS THE AIR MASS IN ONLY MOIST IN A SHALLOW 1500-2KFT
LAYER...AND H8 TEMPS ARE MARGINAL AT BEST. IF SOME MENTION OF LIGHT
LAKE EFFECT IS NEEDED EVENTUALLY...THESE SITUATIONS ARE BEST PLAYED
AS THE TIME COMES...AS ANYTHING THAT DEVELOPS WILL BE INSIGNIFICANT.
925MB TEMPS DO LOOK COOL ENOUGH FOR SOME LOW CLOUDS THAT WILL SHIFT
FROM WESTERLY FLOW REGIMES TO SW...AS WINDS BACK IN ADVANCE OF
AFOREMENTIONED NEXT SHORTWAVE TROUGH.
SUNDAY AND SUNDAY NIGHT...EXPECT A SLOWING OF THIS SHORTWAVE
TROUGH...SINCE THE PATTERN WILL BE AMPLIFYING. MODELS SEEM TO BE
SLOWING ALREADY...WITH A SFC LOW ONLY MAKING IT TO SW ONTARIO...JUST
NORTH OF WESTERN LAKE SUPERIOR...BY 00Z. BAND OF DEEPER H8-H5
MOISTURE...DIVERGENCE IN LEFT EXIT REGION OF 140KT UPPER JET...AND
BEST MID/UPPER LEVEL -DIVQ ARRIVES LATE IN THE AFTERNOON...BUT
REALLY SPREADS ACROSS NRN MICHIGAN SUNDAY NIGHT. WILL KEEP CHANCE OF
SNOW SHOWERS IN THE FORECAST FOR SURE. COULD BE SOME P-TYPE ISSUES
EVENTUALLY WITH THIS SYSTEM...AS DEGREE OF AMPLIFICATION IN THE
UPPER AIR PATTERN WOULD POSSIBLY SUGGEST THAT THE MODELS MIGHT NOT
BE ALLOWING ENOUGH WARM AIR TO GET INTO THE AREA. AS IT STANDS
NOW...MODEL DEPICTIONS OF THE THERMAL PROFILES OUT THIS FAR SUGGEST
SNOW WITH A LITTLE HELP FROM EVAPORATIVE COOLING TO LOWER 2KFT SFC
BASED WARM LAYER TO THE WET BULB. THESE SORT OF DETAILS WILL HAVE TO
BE WORKED OUT IN LATER FORECASTS WHEN THERE WILL BE MORE CONFIDENCE
IN SPECIFIC MODEL DATA. THE OVERALL TREND FOR THE LATE NIGHT HOURS
LEADING INTO MONDAY MORNING HOWEVER...SUGGEST THAT WE WILL SEE THE
COLDER AND COLDER AIR CONTINUING TO SPILL INTO THE REGION. MAYBE
SOME LAKE EFFECT SNOWS DEVELOP BY DAYBREAK ALREADY?
MONDAY THROUGH WEDNESDAY...MAIN WEATHER STORY WILL RESIDE IN THIS
TIME FRAME...AS H8 TEMPS TUMBLE INTO THE -12C RANGE MONDAY AND
MONDAY NIGHT...AND THEN TO -16C BY TUESDAY THROUGH WEDNESDAY. AS
STATED ABOVE...MOISTURE QUESTIONS ARISE MONDAY AND MONDAY NIGHT...
BUT LIGHT LAKE EFFECT SNOW SHOWERS LOOK LIKE A GOOD BET. I DO NOT
LIKE THINKING THAT OUR BEST LOOK AT LAKE EFFECT COMES IN SOME OF THE
LATEST TIME PERIODS OF THE FORECAST...WITH FEATURES THAT COULD
CHANGE IN THE NEXT MODEL RUN. HOWEVER...THIS IS THE CASE. OVERALL
PATTERN OF EVEN COLDER H8 AIR AND SHARPER LONGWAVE TROUGHING OVER
THE GREAT LAKES REGION DOES PROVIDE MORE CONFIDENCE IN THE
DEVELOPMENT OF MORE ROBUST LAKE EFFECT SNOWS THOUGH. NOT READY TO
SAY THESE ARE LIKELY YET...BUT I DO LIKE THE TRENDS. THE COLD AIR
WANTS TO STAY AROUND LONGER NOW TOO...INTO WEDNESDAY MORNING NOW
UNTIL THE THERMAL TROUGH SHIFTS EAST.
WEDNESDAY NIGHT AND THURSDAY...AIR MASS MODIFIES/WARMS AS TROUGH
WEST COAST AND RIDGING EAST COAST REDEVELOPS. THIS IS THE PATTERN
SEEN OVER THE LAST SEVERAL WEEKS...AND CANNOT ARGUE IT. MODELS DO
WANT TO BRING A COLD FRONT THROUGH HERE THURSDAY. DON`T KNOW IF THE
UPPER AIR PATTERN REALLY SUGGESTS THIS...BUT EITHER UNCERTAINTIES
AND NEIGHBORING OFFICE COORDINATION WILL RESULT IN LEAVING A CHANCE
FOR SNOW...POSSIBLY RAIN WEDNESDAY NIGHT INTO THURSDAY. SMD
&&
.APX...WATCHES/WARNINGS/ADVISORIES....NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
AFDMQT 445 AM EST THU JAN 4 2007
.DISCUSSION...
MAIN FCST CONCERNS ARE PCPN CHANCES/TYPE TODAY/TONIGHT AND AGAIN FRI
NIGHT INTO SAT.
WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL NRN STREAM FLOW
ACROSS THE NRN CONUS AND SRN CANADA WITH SEVERAL EMBEDDED WEAK
SHRTWVS. ONE UPSTREAM WAS MOVING ENE THROUGH NE MN WHILE OTHER
STRONGER SHRTWVS TRAILED OVER THE WRN DAKOTAS...NRN NEB AND WRN MT.
WEAK 700-300 QVECTOR CONV AND UPPER LEVEL DIV WITH RIGHT ENTRANCE OF
ONE JET STREAK SUPPORTED SOME VIRGA/SPRINKLES FROM NE MN TO LK
SUPERIOR WHILE THE DAKOTAS SHRTWV HAS ALSO BROUGHT SOME LGT PCPN
INTO CNTRL AND ERN ND. AT THE SFC...SW FLOW CONTINUED ACROSS THE WRN
GREAT LAKES BTWN A 982 MB LOW WAS LOCATED N OF LK WINNIPEG AND HIGH
PRES OVER THE SE CONUS. A WEAK TROF ALSO EXTENDED THROUGH THE
THROUGH THE CNTRL DAKOTAS. TEMPERATURES REMAINED IN THE UPPER 30S TO
LOWER 40S OVERNIGHT...AOA RECORD VALUES IN MANY LOCATIONS.
TODAY AND TONIGHT...THE COMBINATION OF THE UPSTREAM SHRTWVS
AND UPPER LEVEL DIV WITH RIGHT ENTRANCE OF A 300 MB JET LIFTING INTO
NRN ONTARIO WILL HELP SUPPORT PCPN CHANCES OVER MAINLY W LK SUPERIOR
AND THE NW HLF OF UPR MI. IN ADDITION...QVECTOR CONV WILL ALSO
INCREASE AS A HGT FALLS MOVE TOWARD THE AREA ON THE SRN END OF THE
MANITOBA MID LVL LOW. HOWEVER...00Z RAOBS AND UPSTREAM KINL/CYQT
TAMDAR SNDGS CONTINUED TO INDICATE SUBSTANTIAL DRY LYR BTWN 900-700
MB. 00Z NAM/GFS FCST 800-600 MB FGEN FORCING ALSO WAS NOT AS
IMPRESSIVE OR PERSISTENT AS PREVIOUS RUNS WITH THE BEST FORCING
MAINLY NW OF THE CWA. SO...THE FCST INCLUDES ONLY LOWER END CHANCE
POPS. EVEN THOUGH THE GFS...WEAKENS THE 900-700 MB WARM
LAYER...EXPECT THAT THE COOLING MAY BE OVERDONE AS HAS BEEN THE CASE
RECENTLY. WET-BULB ZERO HEIGHTS ALSO REMAIN MAINLY AOA 1K FT THROUGH
MUCH OF TONIGHT. WITH SFC TEMPS ONLY EXPECTED TO REMAIN MAINLY IN
THE MID 30S OR FALL ONLY TO 32F LATE...IF PCPN OCCURS ONLY RAIN IS
EXPECTED.
FRI...QVECTOR DIV AND CAA WITH VEERING WINDS TO WRLY WILL TAKE OVER
WITH DRY CONDITIONS EXPECTED. EVEN THOUGH LOWER CLOUDS MAY THIN OUT
LATE IN THE DAY...HIGH CLOUDS AHEAD OF THE NEXT SHRTWV SHOULD MOVE
IN.
FRI NIGHT INTO SAT...THE GFS HAS CONTINUED TREND TOWARD THE
UKMET/CMC/ECMWF WITH THE SHRTWV AND STRONG BAND OF FGEN REMAINING
MAINLY SOUTH AND EAST OF THE CWA. SO...POPS WERE TRIMMED WITH THE
BEST CHANCE OVER THE SE CWA. ALTHOUGH THE SYNOPTIC FORCING AND
DEEPER MOISTURE REMAINS FARTHER SE WITH NW FLOW AND 00Z GFS 850 MB
TEMPS DROPPING INTO THE -8C TO -10C RANGE FRI NIGHT...SOME LIGHT LES
MAY BE POSSIBLE INTO W UPR MI.
THE GFS/ECMWF/CMC WERE IN DECENT AGREEMENT WITH ANOTHER STRONG
250-300 MB JET STREAK AND SHRTWV FROM THE PAC THROUGH SRN BC WILL
MAKE ITS WAY THROUGH THE NRN PLAINS AND AFFECT THE UPR GREAT LAKES
SUN. WAA HIGH CLOUDS MAY SPREAD THROUGH THE AREA SAT NIGHT BUT NO
PCPN IS EXPECTED WITH VERY DRY AIR REMAINING BLO 700 MB. SINCE
STRONGER QVECTOR CONV WITH THE MID LVL TROF REMAINS W AND N OF THE
CWA...ONLY SLGT CHANCE POPS FOR LIGHT SNOW WERE INCLUDED UNTIL
CAA STRONG CAA MOVES IN SUN NIGHT SUPPORTING LES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
JLB
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
AFDABQ 1108 AM MST THU JAN 4 2007
.UPDATE...DOWNSLOPING FLOW ALONG AND EAST OF THE SANGRES INHIBITED
THE DEVELOPMENT OF AN OVERNIGHT TEMPERATURE INVERSION IN SOME
LOCATIONS...AND ALREADY ERODED THE INVERSION IN SOME OTHERS.
THUS...TEMPERATURES ROSE EARLY THIS MORNING AND WE UPDATED THE
TEMPERATURE FORECAST. ALSO SPREAD BREEZY CONDITIONS TO MORE OF THE
AREA ALONG AND JUST EAST OF THE CENTRAL MOUNTAIN CHAIN FOR THE
REMAINDER OF TODAY. 44
&&
.DISCUSSION...
259 AM MST THU JAN 4 2007...09Z SFC ANALYSIS SHOWS A 1025MB HIGH
PRES CENTER OVER NORTH CENTRAL NM WITH A LEE SFC TROUGH ACROSS
EASTERN NM AND SE CO. CLEAR SKIES OVER NM WILL ALLOW PATCHY FOG
FORMATION THRU MID MORNING IN SAME SPOTS AS LAST COUPLE OF DAYS.
LATEST WATER VAPOR SAT IMAGERY SHOWS ONE UPPER WAVE OVER SOUTH TX
MOVING EAST AND ANOTHER UPPER WAVE DIVING SE INTO THE PAC NW WITH
ZONAL FLOW ALOFT IN BTWN. 400-200MB AIRCRAFT DATA SHOWS AN EXTENSIVE
150-170 KNOT JET EMBEDDED WITHIN THE BASE OF THE PAC NW UPPER WAVE.
00Z MODEL GUIDANCE INDICATES AFOREMENTIONED ZONAL FLOW WILL CONTINUE
OVER NM ALLOWING HIGH CLOUDS TO STREAM ACROSS THE STATE TODAY. 18Z
MREF AND 21Z SREF MEMBERS ARE IN GOOD AGREEMENT WITH PATTERN EVOLN
THROUGH THE FORECAST PERIOD AND SIDED WITH 00Z GFS ON DETAILS.
150-170 KNOT JET WILL WEAKEN SLIGHTLY AS IT TRANSLATES SE INTO THE
DESERT SOUTHWEST FRIDAY. JET AXIS REMAINS ZONAL THRU SAT WITH A
POSITIVE TILT TO THE UPPER LEVEL WAVE SO NOT SEEING ANY MAJOR CUT
OFF LOW DEVELOPING. MOISTURE WITHIN THE TROUGH WILL MOVE INTO NW
CORNER OF THE STATE BY 12Z FRI AND SPREAD SE THROUGH THE CENTRAL
MTNS AND VALLEYS THRU 00Z SAT. AS UPPER WAVE SLIDES EAST EXPECT A
COLD FRONT TO SURGE SOUTHWARD THRU THE NE PLAINS. PRECIP CHANCES
GREATEST ALONG THE EAST SLOPES OF THE NORTH AND CENTRAL MTNS 00Z SAT
THRU 12Z SAT BEFORE SYSTEM QUICKLY EXITS TO THE SE. CONCERN THIS GO
AROUND WILL BE MORE IN THE HIGHER ELEVATIONS IN THE NORTH AND
CENTRAL PORTIONS OF THE STATE LATE THU INTO FRI WITH BLOWING SNOW
AGAIN OVER THE FAR NE PLAINS LATE FRI INTO SAT. THIS WILL LIKELY BE
A PROBLEM SINCE DIGGING OUT FROM THE LAST EVENT IS STILL ONGOING.
CONTINUING TO GO BELOW GUIDANCE ON TEMPS AND WILL LIKELY NEED TO
LOWER AGAIN IN AREAS THAT RECEIVE SNOWFALL LATE THU THRU SAT.
AFTER SYSTEM EXITS SE NM EARLY SAT NW FLOW BUILDS ACROSS THE STATE
ALOFT. MREF MEMBERS IN GOOD AGREEMENT WITH THIS THRU THE EXTENDED AS
A LARGE SCALE RIDGE BUILDS OFF THE COAST OF SOCA THRU WED. THE NEXT
SYSTEM ON THE HORIZON LATE NEXT WEEK COULD BE A BIG ONE. GUYER
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
44
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
AFDABQ 259 AM MST THU JAN 4 2007
.DISCUSSION...
09Z SFC ANALYSIS SHOWS A 1025MB HIGH PRES CENTER OVER NORTH CENTRAL
NM WITH A LEE SFC TROUGH ACROSS EASTERN NM AND SE CO. CLEAR SKIES
OVER NM WILL ALLOW PATCHY FOG FORMATION THRU MID MORNING IN SAME
SPOTS AS LAST COUPLE OF DAYS. LATEST WATER VAPOR SAT IMAGERY SHOWS
ONE UPPER WAVE OVER SOUTH TX MOVING EAST AND ANOTHER UPPER WAVE
DIVING SE INTO THE PAC NW WITH ZONAL FLOW ALOFT IN BTWN. 400-200MB
AIRCRAFT DATA SHOWS AN EXTENSIVE 150-170 KNOT JET EMBEDDED WITHIN
THE BASE OF THE PAC NW UPPER WAVE.
00Z MODEL GUIDANCE INDICATES AFOREMENTIONED ZONAL FLOW WILL CONTINUE
OVER NM ALLOWING HIGH CLOUDS TO STREAM ACROSS THE STATE TODAY. 18Z
MREF AND 21Z SREF MEMBERS ARE IN GOOD AGREEMENT WITH PATTERN EVOLN
THROUGH THE FORECAST PERIOD AND SIDED WITH 00Z GFS ON DETAILS.
150-170 KNOT JET WILL WEAKEN SLIGHTLY AS IT TRANSLATES SE INTO THE
DESERT SOUTHWEST FRIDAY. JET AXIS REMAINS ZONAL THRU SAT WITH A
POSITIVE TILT TO THE UPPER LEVEL WAVE SO NOT SEEING ANY MAJOR CUT OFF
LOW DEVELOPING. MOISTURE WITHIN THE TROUGH WILL MOVE INTO NW CORNER
OF THE STATE BY 12Z FRI AND SPREAD SE THROUGH THE CENTRAL MTNS AND
VALLEYS THRU 00Z SAT. AS UPPER WAVE SLIDES EAST EXPECT A COLD FRONT
TO SURGE SOUTHWARD THRU THE NE PLAINS. PRECIP CHANCES GREATEST ALONG
THE EAST SLOPES OF THE NORTH AND CENTRAL MTNS 00Z SAT THRU 12Z SAT
BEFORE SYSTEM QUICKLY EXITS TO THE SE. CONCERN THIS GO AROUND WILL
BE MORE IN THE HIGHER ELEVATIONS IN THE NORTH AND CENTRAL PORTIONS
OF THE STATE LATE THU INTO FRI WITH BLOWING SNOW AGAIN OVER THE FAR
NE PLAINS LATE FRI INTO SAT. THIS WILL LIKELY BE A PROBLEM SINCE
DIGGING OUT FROM THE LAST EVENT IS STILL ONGOING. CONTINUING TO GO
BELOW GUIDANCE ON TEMPS AND WILL LIKELY NEED TO LOWER AGAIN IN AREAS
THAT RECEIVE SNOWFALL LATE THU THRU SAT.
AFTER SYSTEM EXITS SE NM EARLY SAT NW FLOW BUILDS ACROSS THE STATE
ALOFT. MREF MEMBERS IN GOOD AGREEMENT WITH THIS THRU THE EXTENDED AS
A LARGE SCALE RIDGE BUILDS OFF THE COAST OF SOCA THRU WED. THE NEXT
SYSTEM ON THE HORIZON LATE NEXT WEEK COULD BE A BIG ONE.
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 40 26 36 14 / 0 20 40 30
GALLUP.......................... 49 23 38 8 / 0 5 40 30
GRANTS.......................... 35 9 36 10 / 0 5 40 40
GLENWOOD........................ 57 25 51 26 / 0 0 20 30
CHAMA........................... 39 13 27 -4 / 0 30 80 60
LOS ALAMOS...................... 38 17 32 10 / 0 5 40 50
RED RIVER....................... 40 13 28 -2 / 0 5 60 60
TAOS............................ 39 10 36 5 / 0 10 50 60
SANTA FE........................ 35 13 34 11 / 0 5 30 50
SANTA FE AIRPORT................ 36 14 35 12 / 0 5 20 50
ESPANOLA........................ 37 15 35 10 / 0 5 30 50
ALBUQUERQUE HEIGHTS............. 36 14 39 19 / 0 0 20 40
ALBUQUERQUE VALLEY.............. 39 9 39 16 / 0 0 20 40
ALBUQUERQUE FOOTHILLS........... 36 16 37 15 / 0 0 20 40
ALBUQUERQUE WEST MESA........... 39 15 38 18 / 0 0 20 40
SOCORRO......................... 46 21 43 25 / 0 0 5 50
SANDIA PARK/CEDAR CREST......... 36 18 36 15 / 0 0 30 50
MORIARTY/ESTANCIA............... 40 8 35 17 / 0 0 10 60
CARRIZOZO....................... 49 25 46 24 / 0 0 0 20
RUIDOSO......................... 46 23 45 18 / 0 0 0 40
RATON........................... 50 18 39 9 / 0 5 20 60
LAS VEGAS....................... 45 21 42 14 / 0 0 20 60
ROY............................. 50 29 40 15 / 0 0 10 40
CLAYTON......................... 44 27 38 16 / 0 0 10 50
SANTA ROSA...................... 46 25 45 21 / 0 0 10 40
TUCUMCARI....................... 44 28 42 20 / 0 0 5 40
FORT SUMNER..................... 50 24 53 24 / 0 0 5 40
CLOVIS.......................... 58 30 52 27 / 0 0 0 30
PORTALES........................ 59 29 54 25 / 0 0 0 30
ROSWELL......................... 59 33 55 31 / 0 0 0 30
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
GUYER