Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/27/12
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
838 PM MST MON NOV 26 2012
.UPDATE...HAVE UPDATED TO ADJUST MINS OVERNIGHT AS WE HAVE ALREADY
DROPPED AT OR BLO OUR FORECAST MINS IN A COUPLE OF AREAS. COLDEST
READINGS MAY OCCUR PRIOR TO 2 AM WITH SOME MODIFICATION
THEREAFTER ONCE DRAINAGE WINDS KICK IN. MOUNTAIN WAVE OVERNIGHT
MAY ALSO MODIFY THE LOWS OVERNIGHT IN AND NEAR THE FOOTHILLS. A
COUPLE OF POCKETS OF STRATUS STILL OVER EASTERN LARIMER AND
NORTHWEST WELD...AS WELL AS OVER SEDGWICK AND PHILLIPS COUNTIES
THIS EVENING. LOW CLOUDS WILL DIMINISH IN THOSE AREAS AS WELL OVER
THE NEXT FEW HOURS.
&&
.AVIATION...VFR CONDITIONS OVERNIGHT. NO SIGNIFICANT CHANGES IN
THE UPCOMING TAFS WITH DRAINAGE WINDS AT KDEN AND KAPA. SOME
MOUNTAIN WAVE ACTIVITY COULD KICK UP THE WINDS NEAR KBJC TOWARDS
12Z...MORE THAN IN THE CURRENT TAF SO SOME ADJUSTMENT MAY BE
NECESSARY AROUND THAT TIME.
&&
.PREV DISCUSSION... /ISSUED 313 PM MST MON NOV 26 2012/
SHORT TERM...WEAK SURFACE HIGH SLIDING ACROSS CENTRAL PLAINS
BEHIND THIS MORNING`S COLD FRONT. LOW CLOUDS ACROSS PLAINS STILL
FAIRLY EXTENSIVE BUT BEGINNING TO DISSIPATE EAST OF DENVER. STILL
SOME FOG PERSISTING IN THE FOOTHILLS WEST OF DENVER...ALSO SHOWING
SIGNS OF DISSIPATING. LATEST RUC CONTINUES TO SHOW A SLOW
DISSIPATION OF THE LOW CLOUDS DURING THE EVENING WITH MAINLY CLEAR
SKIES BY MIDNIGHT. THIS LOOKING REASONABLE AS DRIER AIR MOVES INTO
REGION FROM THE WEST. THERE WILL BE SOME INCREASE IN HIGH LEVEL
MOISTURE OVERNIGHT WITH WRF SYNTHETIC SATELLITE IMAGERY SUGGESTING
THE DEVELOPMENT OF A WAVE CLOUD TOWARDS MORNING. WINDS TO INCREASE
AGAIN ACROSS MOUNTAINS AND HIGHER FOOTHILLS AFTER MIDNIGHT AS
NORTHWEST FLOW ALOFT INCREASES. MODELS SHOW CROSS MOUNTAIN FLOW
AROUND 40 KTS AT MOUNTAIN TOP AT MIDNIGHT. SOME GUSTS AROUND 50
MPH POSSIBLE OVERNIGHT ACROSS THE WIND PRONE AREAS AND EXPOSED
SLOPES. OVERNIGHT TEMPERATURES TO BE WARMER NEAR THE FOOTHILLS
WITH COLDER TEMPERATURES IN LOW LYING AREAS OF THE PLAINS. ON
TUESDAY...MODERATE WEST NORTHWEST ALOFT TO PREVAIL AS UPPER RIDGE
BUILDS INTO AREA. GUSTY WINDS WILL CONTINUE ACROSS THE MOUNTAINS
AND FOOTHILLS...EXTENDING INTO THE WESTERN SECTIONS OF THE URBAN
CORRIDOR DURING THE MORNING. SOME GUSTS TO 50 MPH WILL BE POSSIBLE
OVER THE HIGHER EXPOSED AREAS. BY 18Z GRADIENT ACROSS THE PLAINS
AND LOWER FOOTHILLS EXPECTED TO WEAKEN...THUS SHOULD SEE WINDS
DECREASE AS A RESULT. HOWEVER...BREEZY CONDITIONS WILL PERSIST
ACROSS THE MOUNTAINS AND HIGHER FOOTHILLS. MODELS HINT AT WAVE
CLOUD ALONG FOOTHILLS DECREASING DURING THE MORNING...WITH MAINLY
CLEAR SKIES PREVAILING BY AFTERNOON ACROSS THE REGION. AIRMASS
ACROSS PLAINS TO BE MUCH WARMER THAN TODAY WITH HIGHS WARMING INTO
THE MID 50S TO MID 60S. ALSO A SLIGHT WARMUP EXPECTED FOR
MOUNTAINS WITH HIGHS IN THE 40S.
LONG TERM...MODELS HAVE AN UPPER RIDGE MOVING INTO AND OVER THE
FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY. FOR THE MOST PART
..ZONAL FLOW WILL COVER THE CWA INTO THURSDAY MORNING. A WEAK
UPPER TROUGH IS PROGGED TO MOVE THROUGH LATER THURSDAY MORNING
..WITH INCREASING NORTHWESTERLY FLOW ALOFT THE REST OF THURSDAY
AND THURSDAY NIGHT. THE QG VERTICAL VELOCITY FIELDS SHOW BENIGN
SYNOPTIC SCALE ENERGY OVER THE CWA TUESDAY NIGHT THROUGH THURSDAY
NIGHT. NORMAL DUIRNAL WIND PATTERNS ARE EXPECTED TUESDAY NIGHT
..WITH DOWNSLOPE WEDNESDAY AND WEDNESDAY NIGHT. A FAIRLY WEAK
GRADIENT IS PROGGED THURSDAY AND THURSDAY NIGHT...SO NORMAL
PATTERNS ARE LIKELY. FOR MOISTURE...THERE IS VERY LITTLE TUESDAY
NIGHT AND WEDNESDAY. BY WEDNESDAY NIGHT SOME MID AN UPPER LEVEL
MOISTURE IS PROGGED TO MOVE IN. THE NAM HAS SOME FAIRLY DEEP
MOISTURE OVER THE MOUNTAINS THURSDAY MORNING AT 12Z...THE GFS HAS
LESS...THE ECMWF WAY LESS. FOR THE REST OF THURSDAY AND THURSDAY
NIGHT...THERE IS A BIT OF UPPER LEVEL MOISTURE PROGGED. THE QPF
FIELDS HAVE NO MEASURABLE PRECIPITATION NOTED THROUGH THE FIVE
PERIODS...WITH THE EXCEPTION OF A TINY BIT OVER THE FAR NORTHWEST
CWA THURSDAY MORNING AT 12Z ON THE NAM. WILL LEAVE POPS OUT FOR
ALL AREAS FOR NOW. FOR TEMPERATURES...WEDENSDAY`S HIGHS LOOK 1-2 C
WARMER THAN TUESDAY`S. THURSDAY`S HIGHS ARE 0-2 C COOLER THAN
WEDNESDAY`S. FOR THE LATER DAYS...FRIDAY THROUGH MONDAY...MODELS
HAVE WEST-SOUTHWESTERLY FLOW ALOFT...WITH VERY LIMITED MOISTURE.
TEMPERATURES LOOK TO STAY ABOVE SEASONAL NORMALS.
AVIATION...LOW CLOUDS SLOWLY ERODING ACROSS AREA...WITH MVFR
CEILINGS PERSISTING AT BJC AND APA. CLOUDS TO CONTINUE TO ERODE
THROUGH THE EVENING WITH IMPROVING CEILINGS. SHOULD EXPECT VFR
CONDITIONS AT BJC AND APA BY 02Z. VFR CEILINGS TO PREVAIL AT DEN
WITH CEILINGS AROUND 7000 FEET AGL BY 02Z. SKIES TO CLEAR ACROSS
THE AREA AROUND 06Z WITH A GRADUAL INCREASE IN HIGH LEVEL MOISTURE
OVERNIGHT. POTENTIAL FOR MOUNTAIN WAVE CLOUD DEVELOPING ALONG
FOOTHILLS BETWEEN 08Z AND 15Z...SHOULD NOT HAVE MUCH IMPACT ON
AREA AIRPORTS. LIGHT SOUTHEASTERLY WINDS THIS EVENING WITH
DRAINAGE FLOW DEVELOPING BY MIDNIGHT. SPEEDS AROUND 10 KTS
EXPECTED OVERNIGHT...THOUGH GUSTS UP TO 20 KTS POSSIBLE AT BJC.
WINDS TO DECREASE AND BECOME NORTHWEST ACROSS THE AREA BY 18Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....RJK
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1257 AM EST SUN NOV 25 2012
.SYNOPSIS...
COOL AND BLUSTERY CONDITIONS ARE EXPECTED FOR THE REMAINDER OF
THE WEEKEND INTO EARLY NEXT WEEK. UNCERTAINTY REMAINS REGARDING
THE TRACK AND INTENSITY OF A STORM TUESDAY AND WEDNESDAY. MUCH
COLDER WEATHER IS EXPECTED BEHIND THE STORM LATE NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1 AM UPDATE...
ONLY MINOR TWEAKS TO THE FORCAST WITH THIS UPDATE. ADJUSTED SKIES
TOWARD LATEST RAP GUIDANCE WHICH HAS BEEN HANDLING THE STRATO-CU
FROM UPSTREAM. OTHERWISE...ONLY OTHER CHANGES WERE MADE TO BRING
TEMPS/DWPTS UP TO CURRENT TRENDS.
PREVIOUS DISCUSSION...
430 PM UPDATE... WINDS HAVE INCREASED LATE THIS AFTERNOON AS THE
MIXING DEPTH GETS TO NEAR 850 MB. A GUST TO 44 KTS JUST OCCURRED
AT WORCESTER AT 4 PM... WITH 32 KTS WAS REPORTED AT ORANGE MA AND
33 KTS AT PITTSFIELD AT 3 PM. THE NORTHWEST PRESSURE GRADIENT WILL
CONTINUE TO TIGHTEN UP THIS EVENING AND OVERNIGHT IN THE WAKE OF
AN UPPER LEVEL TROUGH SWINGING ACROSS NORTHERN NEW ENGLAND. WINDS
AT 3000-5000 FT OFF THE GROUND ARE FORECAST TO INCREASE TO 40-45
KNOTS OVERNIGHT. IT IS A TRICKY CALL FOR THE WINDS TONIGHT. BUFKIT
SHOWS THAT DESPITE THE COLD AIR ADVECTION...THE WINDS DIMINISH TO
15 KT OVER MOST OF THE INTERIOR AS THE TEMPERATURE DROPS AND THE
MIXING LEVEL IS NOT AS DEEP. A MAJOR EXCEPTION IS ALONG THE
COAST...EVERYWHERE FROM CAPE ANN TO CAPE COD AND ON THE RI
COAST...WHERE IT SHOULD REMAIN GUSTING TO 25 TO 30 KTS OVERNIGHT.
FOR THE MOST PART...LAKE EFFECT SNOW SHOWERS HAVE BEEN CONFINED TO
THE BERKSHIRES. HOWEVER...A LIGHT SPRINKLE WAS REPORTED AT 3 PM IN
NASHUA NH... SO SOME OF THE PRECIPITATION IS HITTING THE GROUND.
CANNOT RULE OUT A FLAKE OF SNOW MAINLY WEST OF THE CONNECTICUT
RIVER THIS EVENING BUT ACTIVITY SHOULD DIMINISH WITH NIGHTFALL.
THE RAP MODEL SHOWS NO PRECIPITATION AFTER 04Z.
LOWS MAINLY IN THE UPPER TEENS TO MID 20S EXCEPT NEAR 30 ALONG THE
IMMEDIATE SOUTH COAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
SUNDAY...
SHOULD BE RATHER SIMILAR TO TODAY. SUNSHINE SHOULD GIVE WAY TO A
FAST MOVING BATCH OF MID LEVEL CLOUDINESS IN THE AFTERNOON LEADING
TO PARTLY TO MOSTLY CLOUDY SKIES. USED A 50-50 BLEND OF GFS AND
NAM FOR SKY GRIDS SINCE THEY DIFFERED ON THE TIMING OF THESE CLOUDS.
IT WILL AGAIN BECOME WINDY WITH GUSTS TO 20 TO 30 KTS FROM MID
MORNING THROUGH MID AFTERNOON AS THE MIXING INCREASES. WINDS
SHOULD DIMINISH LATE IN THE AFTERNOON. HIGHS MAINLY IN THE 40S.
SUNDAY NIGHT...
BECOMING MOSTLY CLEAR WITH LIGHT WINDS AND LOWS 20-30.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
* COLDER...DRY WEATHER EXPECTED EARLY NEXT WEEK
* A STORM IS LIKELY TO AFFECT THE AREA MID WEEK
* COLDER WEATHER EXPECTED LATE NEXT WEEK
24/12Z MODELS ARE STARTING TO SHOW SOME CONSISTENCY THROUGHOUT THE
LONG TERM PORTION OF THE FORECAST. THERE IS STILL PLENTY OF
UNCERTAINTY REGARDING THE MID WEEK STORM...THOUGH THE 06Z GFS/00Z
ECMWF/12Z GFS ALL HAVE SIMILAR SOLUTIONS WITH LOW PRESSURE MOVING
OFF THE MID ATLANTIC COAST AND TRAVELING JUST SOUTH OF THE 40/70
BENCHMARK AND BRINGING SNOW TO MUCH OF THE AREA WITH A FOCUS ON THE
SOUTHERN PORTIONS OF SOUTHERN NEW ENGLAND. HOWEVER...THE 12Z NAM
/AN OUTLIER AT THIS POINT/ SIMPLY HAS HIGH PRESSURE OVER THE REGION
AND NO INDICATION OF PRECIP AT ALL. WILL TREND TOWARD A
ECMWF/GFS/HPC SOLUTION... HOWEVER...KEEPING IN MIND ALL THE FLIP
FLOPPING AND UNCERTAINTY WILL ONLY TREND TOWARD IT.
ASIDE FROM THE STORM...THE WEATHER IS FAIRLY QUIET BOTH EARLY AND
LATE NEXT WEEK WITH NORTHWESTERLY FLOW BRINGING COLDER TEMPERATURES.
MONDAY...STRONG NORTHWESTERLY FLOW WILL CONTINUE TO KEEP TEMPS
SLIGHTLY BELOW NORMAL. HIGH PRESSURE BUILDS IN KEEPING MOSTLY CLEAR
SKIES THROUGH THE DAY AND INTO THE EVENING.
TUESDAY INTO WEDNESDAY...GIVEN THE NUMEROUS SOLUTIONS OVER THE LAST
SEVERAL DAYS AM STILL HESITANT TO MAKE A RUN FOR A SINGLE SOLUTION.
THAT SAID...THE ECMWF AND GFS HAVE STARTED TO FOCUS TOWARDS LOW
PRESSURE ON A SOUTHERLY TRACK ALONG OR JUST SOUTH OF THE 40/70
BENCHMARK FOR WINTER STORMS. AT THIS POINT...THIS SOLUTION BRINGS
HEAVY SNOW...LIKELY FOCUSED MORE ON THE SOUTHERN AREAS OF THE CWA
MAINLY ON TUESDAY NIGHT INTO WEDNESDAY. THERE ARE STILL OTHER
SOLUTIONS...THE NAM HAS HIGH PRESSURE OVER THE REGION TUESDAY.
HOWEVER...AT THIS POINT...THE ECMWF/GFS SOLUTION APPEARS THE MOST
LIKELY. WILL TREND TOWARD THIS SOLUTION...BUT CONFIDENCE IS STILL
LOW.
THURSDAY AND FRIDAY...DESPITE ALL THE DISCREPANCIES/UNCERTAINTY FOR
EARLIER IN THE PERIOD...THESE TWO PERIODS HAVE FAIRLY GOOD AGREEMENT
AMONGST THE MODELS. NORTHWESTERLY FLOW WITH THE COOLEST TEMPS OF
THE SEASON THUS FAR MOVING IN ON STRONG COLD AIR ADVECTION. LOOKS
LIKE A COLD AND BRISK END TO THE WEEK.
&&
.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
OVERVIEW...MODERATE TO HIGH CONFIDENCE.
MOSTLY VFR THROUGH MONDAY. AFTER SOME CLEARING THIS MORNING...A
SHORTWAVE WILL LEAD TO INCREASING LOW AND MID CLOUDS THIS
AFTERNOON...BUT CIG HEIGHTS ARE EXPECTED TO REMAIN VFR THRUT.
OTHERWISE...CAN/T RULE OUT SOME LIGHT SNOW SHOWERS PARTICULARLY
TERMINALS NW OF A LINE FROM BDL-ORH-MHT IN THE AFTERNOON AND
EVENING SUN...BUT ONCE AGAIN...SAVE FOR BRIEF REDUCTIONS IN VSBY.
VFR IS EXPECTED TO DOMINATE.
WINDS SLACKEN A BIT WITH GUSTS GENERALLY 15-25 THRUT 06Z-12Z BUT
INCREASE AGAIN WITH W-NW GUSTS 20-30 KT DURING THE DAY SUN. WINDS
THEN SLACKEN OFF SIGNIFICANTLY OVERNIGHT SUN NIGHT.
KBOS TAF...MODERATE TO HIGH CONFIDENCE.
GENERALLY VFR EXPECTED. W-NW WINDS TONIGHT WITH GUSTS 20-25 KT
THROUGH 12Z...25-30 KT DURING THE DAY.
KBDL TAF...HIGH CONFIDENCE.
GENERALLY VFR. CANNOT RULE OUT A BRIEF FLURRY LATE THIS AFTERNOON
AND EVENING. OTHERWISE W-NW WINDS GUSTING TO 20 KT THROUGH
12Z...25-30 KT AFTER 12Z.
OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...
MONDAY...HIGH CONFIDENCE. VFR.
TUESDAY THROUGH WEDNESDAY MORNING...LOW CONFIDENCE. MVFR/IFR
CONDITIONS POSSIBLE IN POTENTIAL RA/SN/FZRA/SNPL.
WEDNESDAY AFTERNOON THROUGH THURSDAY...MODERATE TO HIGH CONFIDENCE.
VFR.
&&
.MARINE...
MODERATE CONFIDENCE INTO SUNDAY NIGHT...
GALE WARNINGS CONTINUE FOR THE COASTAL WATERS INCLUDING NANTUCKET
SOUND...EXCEPT FOR THE INNER HARBORS AND BAYS WHERE SMALL CRAFT
ADVISORIES ARE POSTED. AS AN UPPER LEVEL SHORT WAVE TROUGH SWINGS
THROUGH NORTHERN NEW ENGLAND OVERNIGHT...W TO NW WINDS WILL
CONTINUE TO INCREASE OVER THE COASTAL WATERS...REACHING 35 KTS
OVER THE GALE WARNING AREA AND CONTINUING INTO MUCH OF SUNDAY.
THERE IS A CHANCE THAT A FEW GUSTS TO GALE FORCE COULD OCCUR
CLOSER TO THE COAST IN THE SMALL CRAFT ADVISORY AREA...BUT
FREQUENT GUSTS ARE NOT EXPECTED. ONE CONCERN IS A GUST TO 44 KTS
AT WORCESTER AIRPORT RIGHT AT 4 PM... BUT WE ARE THINKING THAT
THIS IS ELEVATIONAL AND STILL RELATED TO THE MAXIMUM MIXING OF THE
AFTERNOON. WE WILL NEED TO WATCH THIS CLOSELY IN CASE GALES ARE
NEEDED EVERYWHERE ALONG THE COAST OVERNIGHT.
SEAS ARE FORECAST TO CONTINUE TO BUILD TO 8 TO 11 FEET ACROSS THE
OUTER WATERS TONIGHT.
WINDS SHOULD BEGIN TO DIMINISH TO BELOW GALE FORCE IN THE
AFTERNOON BUT SMALL CRAFT ADVISORY LEVEL WIND GUSTS TO 25 KTS MAY
CONTINUE OVER THE OUTER WATERS THROUGH SUNDAY NIGHT. SLOWLY
SUBSIDING SEAS SUNDAY NIGHT.
OUTLOOK...MONDAY THROUGH THURSDAY...
MODERATE CONFIDENCE THROUGH THE PERIOD.
SEAS WILL FALL BELOW 5 FEET LATE MONDAY AND REMAIN BELOW THROUGH
LATE TUESDAY. THEN SEAS WILL BUILD AGAIN AS LOW PRESSURE APPROACHES
THE WATERS LATE TUESDAY INTO WEDNESDAY AND REMAIN ABOVE 5 FEET
THROUGH THE PERIOD. WINDS WILL REMAIN BELOW 25 KTS THROUGH TUESDAY.
WINDS INCREASE TO 25 TO 30 KTS WEDNESDAY AND THURSDAY AS LOW
PRESSURE MOVES ACROSS THE WATERS. LOW PROBABILITY OF GALES LATE
WEDNESDAY INTO THURSDAY.
&&
.FIRE WEATHER...
NO HEADLINES ARE ANTICIPATED BUT FELT IT WAS WORTH MENTIONING THAT
THE MINIMUM RELATIVE HUMIDITIES WILL BE DOWN AROUND 30 PERCENT
SUNDAY AFTERNOON. WINDS WILL BE GUSTING TO 20 TO 30 MPH BUT WILL
BE DIMINISHING IN THE MID TO LATE AFTERNOON AT THE TIME OF THE
MINIMUM HUMIDITIES.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...GALE WARNING UNTIL 10 AM EST THIS MORNING FOR ANZ232>235-237-
256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ230-
231-236-251.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR ANZ250-254-255.
&&
$$
SYNOPSIS...RLG/GAF
NEAR TERM...DOODY/RLG/GAF
SHORT TERM...GAF
LONG TERM...RLG
AVIATION...DOODY/RLG
MARINE...RLG/GAF
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
302 AM CST SUN NOV 25 2012
.DISCUSSION...
919 PM CST
NO SIGNIFICANT CHANGES IN THE FORECAST FOR THE REST OF TONIGHT
BESIDES MINOR TWEAKING OF GRIDDED DATA TO FIT WITH CURRENT
CONDITIONS.
WITH THE WARM AIR ADVECTION AND THICKENING CLOUDS AHEAD OF THE
SHORT WAVE TROUGH MOVING EAST-SOUTHEAST OVER NORTHWEST AND
SOUTHWEST MN AS WELL AS NORTHWEST IA THIS EVENING TEMPERATURES
HAVE HELD STEADY OR EVEN RECOVERED UP TO A COUPLE OF DEGREES F AS
THE SOUTH WINDS HAVE PICKED UP A BIT. NIGHTTIME MINIMUMS LIKELY
ALREADY REACHED SOME LOCATIONS WHILE OTHERS FALL OR RISE A DEGREE
OR TWO OVERNIGHT.
BY MID EVENING THE THICKENING MID LEVEL CLOUDS HAD SPREAD OVER ALL
BUT THE FAR SOUTH AND SOUTHEAST PARTS OF THE FORECAST AREA. RADAR
HAS BEEN DETECTING SOME RETURNS OF LATE AS LIFT RESULTING FROM
THE WARM AIR ADVECTION INCREASES. HOWEVER...LOW LEVELS ACROSS
SOUTHERN WI AS WELL AS NORTHERN IL AND NORTHWEST IN ARE DRY AND
ANY METEORS FALLING FROM THESE MID LEVEL CLOUDS HAVE BEEN AND
WILL CONTINUE TO EVAPORATE BEFORE THEY CAN REACH THE SURFACE.
TRS
//PREV DISCUSSION...
234 PM CST
THE FORECAST CHALLENGES FOR TODAY ARE MAINLY TEMPERATURES AS
READINGS LOOK TO WARM LATER THIS EVENING THROUGH THE DAY SUNDAY
THEN A COOL DOWN INTO MONDAY...FOLLOWED BY A WARM-UP WITH WHAT
LOOKS TO POTENTIALLY BE 50S TO END NOVEMBER AND START
METEOROLOGICAL WINTER.
THE STUBBORN CYCLONIC FLOW AND ITS PESKY STRATUS IS ON THE WAY OUT
WITH A SURFACE RIDGE AXIS MOVING QUICKLY OVER THE AREA THIS EVE.
MID-LEVEL WARM AIR ADVECTION CLOUDS ARE ALREADY SPREADING OVER THIS
RIDGE ACROSS WESTERN IL AND SHOULD QUICKLY EXPAND EAST THROUGH THE
EVE. BEFORE THE ARRIVAL OF THESE CLOUDS IN THE HOURS AFTER
SUNSET...EASTERN AREAS SHOULD SEE TEMPERATURE DROPS THROUGH THE
20S GIVEN LIGHT WINDS. A GRADUAL CLIMB IN TEMPERATURES IS THEN
EXPECTED AREA WIDE AS PRESSURE FALLS AND RETURN FLOW SPREAD IN.
TEMPERATURES ARE LIKELY TO CLIMB BACK TO THE UPPER 20S TO MID 30S
BY DAYBREAK ON SUNDAY.
THE WARM AIR ADVECTION CLOUDS TONIGHT ARE ASSOCIATED WITH A STRONG
UPPER LEVEL LOW MOVING EAST ACROSS NORTHERN SASKATCHEWAN AND
MANITOBA...AND MORE SO WITH A RELATED PV ANOMALY AND SHORT WAVE
EXTENDING SOUTHWARD. THIS WILL TRANSLATE INTO WI BY OVERNIGHT AND
ALREADY TO THE EASTERN GREAT LAKES BY SUNDAY MORNING. SUPPORT FOR
UPWARD MOTION DOES SPREAD THIS FAR SOUTH AS REFLECTED IN RAP AND
NAM Q-VECTOR CONVERGENCE FIELDS. HOWEVER...SATURATION AND MID-
LEVEL MOISTURE CONVERGENCE IS BETTER SITUATED TO THE NORTH. THIS
DISJOINT WILL LIKELY KEEP PRECIPITATION TO THE NORTH...THOUGH
FLURRIES COULD GET CLOSE TO THE WI/IL STATE LINE LATER THIS EVE.
THE WARM SECTOR OF THIS CLIPPER-LIKE SYSTEM WILL CONTINUE OVER THE
AREA INTO SUNDAY. THIS HAS OFFERED 40S TO THE WEST OF THE REGION
IN NEBRASKA TODAY...AND ENVISION LOWER TO MID 40S DURING THE DAY
SUNDAY HERE. AS THE COLD FRONT MOVES THROUGH...WINDS WILL TURN
MORE NORTHWEST BY NIGHT AND TEMPERATURES WILL FALL BACK INTO THE
20S FOR LOWS.
TRENDS CONTINUE TO SUPPORT THIS LOW-LEVEL COOL AIR AND RIDGING
PUSH FROM THE NORTH TO EVOLVE THE PRIMARY BAROCLINIC ZONE TO THE
SOUTH OF THE AREA ON MON NIGHT AND TUE...AND THUS KEEP THE
PRIMARY FORCING FOR PRECIPITATION THERE AS WELL. AS THIS UNFOLDS
THOUGH...THERE STILL IS A WINDOW FOR SMALL CHANCES OF LIGHT SNOW
ACROSS THE SOUTHERN FORECAST AREA...MAINLY LATER MONDAY AFTERNOON
AND NIGHT. THE SPREAD IN THE SREF AND GEFS MEMBERS IS NOW LOW OVER
THE AREA...SO CONFIDENCE ON THIS IS FAIRLY HIGH.
BEYOND THIS...TEMPERATURES WILL SLOWLY MODERATE THROUGH MID WEEK
AS UPPER LEVEL RIDGING ACROSS THE WESTERN STATES EASES EAST.
WITH A LARGE CLOSED LOW OFF THE WEST COAST FORECAST CONSISTENTLY
BY GUIDANCE...THERE WILL BE LITTLE PROGRESSION OF MAJOR WEATHER
SYSTEMS. A QUICK MOVING UPPER LEVEL JET MAX AND ASSOCIATED SHORT
WAVE IS SEEN ON THU NIGHT/FRIDAY WITHIN THE SUITE OF LONG RANGE
GUIDANCE. AGAIN THERE CONTINUES TO BE DECENT BUT SHORT-LIVED
DYNAMICS FORECAST WITH THIS. HAVE INCREASED POPS SOME FROM A
PROVIDED GUIDANCE BLEND. TEMPERATURE SPREAD BY DAYS 6 AND 7 IN THE
FORECAST REALLY INCREASES IN GUIDANCE...SO CONFIDENCE
DROPS...HOWEVER GUIDANCE IS FAVORING TEMPERATURES TO BE ABOVE
NORMAL. ONE OF THE REASONS FOR SUCH SPREAD LOOKS TO BE CLOUD
COVER...AS THE DETERMINISTIC GFS DRAGS UP QUITE A BIT OF LOW-LEVEL
JUICE WITH THE THU NIGHT/FRI WAVE THAT MAY BE TOUGH TO SCOUR THIS
TIME OF YEAR.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* SW WINDS ARND 10 KT WILL SHIFT TO THE NW IN THE AFTN.
BEACHLER
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE HAS DRIFTED TO THE SOUTHEAST OF THE REGION ACROSS
THE TENN VALLEY. THIS HAS ALLOWED WINDS TO SHIFT SOUTHWEST ACROSS
NORTHERN IL/NORTHWEST IN. HOWEVER...A WEAK UPPER LEVEL SYSTEM THAT
IS CURRENTLY BRINGING MID/UPR LEVEL CLOUDS TO NORTHERN
IL/NORTHWEST IN AIRFIELDS...WILL PUSH A FRONTAL BOUNDARY ACROSS
THE REGION LATER TODAY. THIS WILL ALLOW WINDS TO SHIFT WEST THEN
NORTHWEST...WITH SPEEDS GENERALLY AROUND 10 KT. A FEW GUSTS MAY
OCCUR PERIODICIALLY THROUGHOUT THE AFTN IN THE 14 TO 18 KT RANGE.
OVERALL EXPECT VFR CONDS TO PREVAIL THROUGHOUT THE ENTIRE CURRENT
TAF TIMEFRAME.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN CIGS/VSBY FORECAST.
* HIGH CONFIDENCE IN WIND SPEED FORECAST.
* MEDIUM CONFIDENCE IN WIND DIR CHANGE.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...VFR.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...CHC RAIN/SNOW THURSDAY NIGHT.
FRIDAY...CHC RAIN.
BMD
&&
.MARINE...
257 AM CST
ACROSS THE NORTHERN GREAT LAKES...THE GRADIENT IS EXPECTED TO
TIGHTEN. THUS RESULTING IN INCREASED SOUTHWEST WINDS BETWEEN 15-25KT
TODAY. AS A BOUNDARY SLIDES SOUTH ACROSS THE LAKE...WINDS WILL
SLOWLY SHIFT TO NORTHWEST. IN ADDITION THE GRADIENT APPEARS TO
REMAIN TIGHT ACROSS MUCH OF THE LAKE...WHICH MOST LIKELY WILL RESULT
IN WINDS AROUND 30 KT TONIGHT THROUGH MUCH OF MONDAY. AT THIS TIME
IT APPEARS WINDS WILL REMAIN SUB-GALE CRITERIA...HOWEVER AN
OCCASIONAL GUST TO GALE FORCE MAY OCCUR.
ANOTHER RIDGE OF HIGH PRESSURE WILL SLIDE EAST FROM THE CENTRAL
PLAINS MONDAY NIGHT...ARRIVING ACROSS THE GREAT LAKES REGION
TUESDAY. THIS WILL ALLOW WINDS TO SHIFT YET AGAIN TO THE
WEST/SOUTHWEST. TUESDAY A WEAK LOW PRESSURE WILL TRAVERSE CENTRAL
ONTARIO...AND COULD RESULT IN WINDS NEAR THE STRAITS OF MACKINAW
SHIFTING TO NORTH/NORTHEAST FOR A PERIOD OF TIME. THEN ANOTHER
AREA OF LOW PRESSURE IS FORECAST TO SLIDE ACROSS ONTARIO
TUE/WED...WITH HIGH PRESSURE QUICKLY BUILDING IN BEHIND THIS
FEATURE FOR WED NGT/THUR.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...6 PM SUNDAY
TO 9 AM MONDAY.
SMALL CRAFT ADVISORY...LMZ744-LMZ745...6 PM SUNDAY TO 10 PM
MONDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1158 PM CST SAT NOV 24 2012
.DISCUSSION...
919 PM CST
NO SIGNIFICANT CHANGES IN THE FORECAST FOR THE REST OF TONIGHT
BESIDES MINOR TWEAKING OF GRIDDED DATA TO FIT WITH CURRENT
CONDITIONS.
WITH THE WARM AIR ADVECTION AND THICKENING CLOUDS AHEAD OF THE
SHORT WAVE TROUGH MOVING EAST-SOUTHEAST OVER NORTHWEST AND
SOUTHWEST MN AS WELL AS NORTHWEST IA THIS EVENING TEMPERATURES
HAVE HELD STEADY OR EVEN RECOVERED UP TO A COUPLE OF DEGREES F AS
THE SOUTH WINDS HAVE PICKED UP A BIT. NIGHTTIME MINIMUMS LIKELY
ALREADY REACHED SOME LOCATIONS WHILE OTHERS FALL OR RISE A DEGREE
OR TWO OVERNIGHT.
BY MID EVENING THE THICKENING MID LEVEL CLOUDS HAD SPREAD OVER ALL
BUT THE FAR SOUTH AND SOUTHEAST PARTS OF THE FORECAST AREA. RADAR
HAS BEEN DETECTING SOME RETURNS OF LATE AS LIFT RESULTING FROM
THE WARM AIR ADVECTION INCREASES. HOWEVER...LOW LEVELS ACROSS
SOUTHERN WI AS WELL AS NORTHERN IL AND NORTHWEST IN ARE DRY AND
ANY METEORS FALLING FROM THESE MID LEVEL CLOUDS HAVE BEEN AND
WILL CONTINUE TO EVAPORATE BEFORE THEY CAN REACH THE SURFACE.
TRS
//PREV DISCUSSION...
234 PM CST
THE FORECAST CHALLENGES FOR TODAY ARE MAINLY TEMPERATURES AS
READINGS LOOK TO WARM LATER THIS EVENING THROUGH THE DAY SUNDAY
THEN A COOL DOWN INTO MONDAY...FOLLOWED BY A WARM-UP WITH WHAT
LOOKS TO POTENTIALLY BE 50S TO END NOVEMBER AND START
METEOROLOGICAL WINTER.
THE STUBBORN CYCLONIC FLOW AND ITS PESKY STRATUS IS ON THE WAY OUT
WITH A SURFACE RIDGE AXIS MOVING QUICKLY OVER THE AREA THIS EVE.
MID-LEVEL WARM AIR ADVECTION CLOUDS ARE ALREADY SPREADING OVER THIS
RIDGE ACROSS WESTERN IL AND SHOULD QUICKLY EXPAND EAST THROUGH THE
EVE. BEFORE THE ARRIVAL OF THESE CLOUDS IN THE HOURS AFTER
SUNSET...EASTERN AREAS SHOULD SEE TEMPERATURE DROPS THROUGH THE
20S GIVEN LIGHT WINDS. A GRADUAL CLIMB IN TEMPERATURES IS THEN
EXPECTED AREA WIDE AS PRESSURE FALLS AND RETURN FLOW SPREAD IN.
TEMPERATURES ARE LIKELY TO CLIMB BACK TO THE UPPER 20S TO MID 30S
BY DAYBREAK ON SUNDAY.
THE WARM AIR ADVECTION CLOUDS TONIGHT ARE ASSOCIATED WITH A STRONG
UPPER LEVEL LOW MOVING EAST ACROSS NORTHERN SASKATCHEWAN AND
MANITOBA...AND MORE SO WITH A RELATED PV ANOMALY AND SHORT WAVE
EXTENDING SOUTHWARD. THIS WILL TRANSLATE INTO WI BY OVERNIGHT AND
ALREADY TO THE EASTERN GREAT LAKES BY SUNDAY MORNING. SUPPORT FOR
UPWARD MOTION DOES SPREAD THIS FAR SOUTH AS REFLECTED IN RAP AND
NAM Q-VECTOR CONVERGENCE FIELDS. HOWEVER...SATURATION AND MID-
LEVEL MOISTURE CONVERGENCE IS BETTER SITUATED TO THE NORTH. THIS
DISJOINT WILL LIKELY KEEP PRECIPITATION TO THE NORTH...THOUGH
FLURRIES COULD GET CLOSE TO THE WI/IL STATE LINE LATER THIS EVE.
THE WARM SECTOR OF THIS CLIPPER-LIKE SYSTEM WILL CONTINUE OVER THE
AREA INTO SUNDAY. THIS HAS OFFERED 40S TO THE WEST OF THE REGION
IN NEBRASKA TODAY...AND ENVISION LOWER TO MID 40S DURING THE DAY
SUNDAY HERE. AS THE COLD FRONT MOVES THROUGH...WINDS WILL TURN
MORE NORTHWEST BY NIGHT AND TEMPERATURES WILL FALL BACK INTO THE
20S FOR LOWS.
TRENDS CONTINUE TO SUPPORT THIS LOW-LEVEL COOL AIR AND RIDGING
PUSH FROM THE NORTH TO EVOLVE THE PRIMARY BAROCLINIC ZONE TO THE
SOUTH OF THE AREA ON MON NIGHT AND TUE...AND THUS KEEP THE
PRIMARY FORCING FOR PRECIPITATION THERE AS WELL. AS THIS UNFOLDS
THOUGH...THERE STILL IS A WINDOW FOR SMALL CHANCES OF LIGHT SNOW
ACROSS THE SOUTHERN FORECAST AREA...MAINLY LATER MONDAY AFTERNOON
AND NIGHT. THE SPREAD IN THE SREF AND GEFS MEMBERS IS NOW LOW OVER
THE AREA...SO CONFIDENCE ON THIS IS FAIRLY HIGH.
BEYOND THIS...TEMPERATURES WILL SLOWLY MODERATE THROUGH MID WEEK
AS UPPER LEVEL RIDGING ACROSS THE WESTERN STATES EASES EAST.
WITH A LARGE CLOSED LOW OFF THE WEST COAST FORECAST CONSISTENTLY
BY GUIDANCE...THERE WILL BE LITTLE PROGRESSION OF MAJOR WEATHER
SYSTEMS. A QUICK MOVING UPPER LEVEL JET MAX AND ASSOCIATED SHORT
WAVE IS SEEN ON THU NIGHT/FRIDAY WITHIN THE SUITE OF LONG RANGE
GUIDANCE. AGAIN THERE CONTINUES TO BE DECENT BUT SHORT-LIVED
DYNAMICS FORECAST WITH THIS. HAVE INCREASED POPS SOME FROM A
PROVIDED GUIDANCE BLEND. TEMPERATURE SPREAD BY DAYS 6 AND 7 IN THE
FORECAST REALLY INCREASES IN GUIDANCE...SO CONFIDENCE
DROPS...HOWEVER GUIDANCE IS FAVORING TEMPERATURES TO BE ABOVE
NORMAL. ONE OF THE REASONS FOR SUCH SPREAD LOOKS TO BE CLOUD
COVER...AS THE DETERMINISTIC GFS DRAGS UP QUITE A BIT OF LOW-LEVEL
JUICE WITH THE THU NIGHT/FRI WAVE THAT MAY BE TOUGH TO SCOUR THIS
TIME OF YEAR.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* SW WINDS ARND 10 KT WILL SHIFT TO THE NW IN THE AFTN.
BEACHLER
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE HAS DRIFTED TO THE SOUTHEAST OF THE REGION ACROSS
THE TENN VALLEY. THIS HAS ALLOWED WINDS TO SHIFT SOUTHWEST ACROSS
NORTHERN IL/NORTHWEST IN. HOWEVER...A WEAK UPPER LEVEL SYSTEM THAT
IS CURRENTLY BRINGING MID/UPR LEVEL CLOUDS TO NORTHERN
IL/NORTHWEST IN AIRFIELDS...WILL PUSH A FRONTAL BOUNDARY ACROSS
THE REGION LATER TODAY. THIS WILL ALLOW WINDS TO SHIFT WEST THEN
NORTHWEST...WITH SPEEDS GENERALLY AROUND 10 KT. A FEW GUSTS MAY
OCCUR PERIODICIALLY THROUGHOUT THE AFTN IN THE 14 TO 18 KT RANGE.
OVERALL EXPECT VFR CONDS TO PREVAIL THROUGHOUT THE ENTIRE CURRENT
TAF TIMEFRAME.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN CIGS/VSBY FORECAST.
* HIGH CONFIDENCE IN WIND SPEED FORECAST.
* MEDIUM CONFIDENCE IN WIND DIR CHANGE.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...VFR.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...CHC RAIN/SNOW THURSDAY NIGHT.
FRIDAY...CHC RAIN.
BMD
&&
.MARINE...
217 PM...A RIDGE OF HIGH PRESSURE WILL PASS ACROSS LAKE MICHIGAN
EARLY THIS EVENING AS LOW PRESSURE OVER SOUTHERN MANITOBA MOVES
EAST ACROSS THE NORTHERN LAKES SUNDAY AND WEAKENS SUNDAY NIGHT.
THE GRADIENT WILL TIGHTEN TONIGHT BETWEEN THE APPROACHING LOW AND
THE WEAKENING RIDGE. WEST WINDS WILL SHIFT SOUTHWESTERLY THIS
EVENING AND STEADILY INCREASE TO 15-25KTS BY LATE EVENING AND
OVERNIGHT. SOME GUSTS TO 30 KTS ARE POSSIBLE ESPECIALLY OVER THE
SOUTHERN PART OF THE LAKE WHERE THE GRADIENT WILL BE TIGHTEST. A
TRAILING COLD FRONT FROM THIS LOW WILL MOVE ACROSS THE LAKE SUNDAY
AFTERNOON SHIFTING WINDS WESTERLY. AS ANOTHER AREA OF HIGH
PRESSURE MOVES SOUTHEAST FROM THE NORTHERN PLAINS SUNDAY NIGHT TO
THE SOUTHERN LAKES AND OHIO VALLEY MONDAY...THE GRADIENT WILL ONCE
AGAIN TIGHTEN WITH NORTHWEST WINDS 20-25KTS EXPECTED. GRADIENT
COULD BE STRONG ENOUGH FOR GUSTS TO 30KTS OVER NORTHERN LAKE
MICHIGAN. AS THIS HIGH SETTLES SOUTH OF THE LAKE ON TUESDAY...
WINDS WILL TURN SOUTHWESTERLY AND SHOULD RAPIDLY STRENGTHEN
TUESDAY AFTERNOON AS ANOTHER LOW MOVES ACROSS ONTARIO AND THE
NORTHERN LAKES WITH 30KTS AGAIN POSSIBLE OVER THE NORTHERN HALF OF
THE LAKE. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE
MIDWEST AND LAKES REGION MID WEEK. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1139 AM CST SUN NOV 25 2012
.SHORT TERM /TODAY/...
SOMEWHAT COMPLICATED SHORT TERM TODAY AS MODELS NOT HANDLING THE
CLOUD COVER OVER MINNESOTA AT ALL. RAP MODEL HAS A BETTER IDEA THAT
STRATUS HAS FORMED AND HEADING SOUTH INTO THE REGION TODAY.
MEANWHILE THERE IS AN UPPER LEVEL BOUNDARY WITH UPSLOPE CLOUDS AND
LIGHT SNOW THAT IS ALSO CREATING A SHIELD OF CLOUDS SCHEDULED TO
HEAD EAST TOWARDS US LATER TODAY. THE COMBINATION OF SOME CLOUDS
EARLY AND MORE CLOUDS LATER WILL DAMPEN HIGHS TODAY. ALSO...THE
MAIN COLD FRONT NOW OVER NORTHWEST IOWA WILL SLIDE SOUTHEAST TODAY
KEEPING NORTHERN IOWA COOLER THAN THE REST OF THE REGION. HIGHS
THERE SHOULD TOP OUT IN THE MID 30S WHILE...WITH THE HEAD START IN
THE MID 30S...CENTRAL AND SOUTHERN IOWA WILL REACH THE LOWER TO MID
40S BY THE MID AFTERNOON. SOME AREAS MAY SEE AMPLE SUN EARLY TODAY
BUT WITH THICKENING CLOUDS MOST OF THE MORNING NORTH AND WEST/SOUTH
REGIONS LATER IN THE AFTERNOON IT SHOULD BE PARTLY SUNNY AT BEST IN
MANY LOCATIONS. WINDS WILL PICK UP BEHIND THE COLD FRONT AND
INCREASE TO ABOUT 10 TO 20 MPH WITH A FEW HIGHER GUSTS BY 2 TO 4 PM
AND THEN DIMINISH BY EVENING. NO PRECIPITATION IS EXPECTED.
.LONG TERM /TONIGHT THROUGH SATURDAY/...
A ZONAL THE NORTHWEST FLOW WILL REMAIN OVER THE CENTRAL CONUS FOR
THE BULK OF THE FORECAST PERIOD. THERE WILL ALSO BE VERY LITTLE
MOISTURE AROUND. THERE ARE SEVERAL SHORTWAVES IN THE UPPER FLOW AND
A COLD FRONT EXPECTED TO CONTINUE TO PASS EAST TONIGHT WITH LITTLE
FANFARE. COLDER AIR WILL SPILL INTO CENTRAL IOWA FOR MONDAY AND
MONDAY NIGHT. A DECENT SHORTWAVE IS PROGGED BY EVERY MEDIUM RANGE
MODEL TO PASS ACROSS THE STATE VERY LATE SUNDAY NIGHT THROUGH
MONDAY. WHAT IS ALSO INTERESTING IS THAT EVERY MODEL DEEPENS THE
WAVE JUST BEFORE IS SWINGS ACROSS IOWA...PUSHING THE FORCING AND THE
PRECIP A LITTLE FURTHER SOUTH. WITH A PRETTY DRY AIRMASS IN PLACE
AND THE FORCING ROM THE SHORTWAVE NOW SHIFTING SOUTH...I EXPECT
LITTLE MORE THAN FLURRIES ACROSS THE FAR SOUTHWEST AND SOUTH.
SHOULD THIS WAVE NOT DEEPEN AS MUCH OR IF THERE IS MORE MOISTURE
WITH THIS SYSTEM THAN THE MODELS ARE SUGGESTING THEN POPS WILL NEED
TO BE RAISED BUT FOR NOW...FLURRIES WILL COVER THE THREAT.
FOR MONDAY NIGHT THROUGH WEDNESDAY AN UPPER LEVEL RIDGE TRIES TO
ESTABLISH ITSELF OVER THE INTERMOUNTAIN WEST KEEPING A NORTHWEST
FLOW ACROSS THE UPPER MIDWEST. DRY AND SEASONAL TO SLIGHTLY BELOW
NORMAL TEMPERATURES ARE EXPECTED DURING THIS TIME.
MODELS DIVERGE SOME THURSDAY NIGHT INTO THE REMAINDER OF THE
EXTENDED. THE GFS DEVELOPS ANOTHER DECENT SHORTWAVE OVER THE REGION
AND THE GEM IS A LITTLE WEAKER AND FURTHER EAST WITH THIS FEATURE
WHILE THE EURO BARELY HAS A REFLECTION IN A MAINLY ZONAL FLOW. AT
THIS TIME I WILL KEEP THIS PERIOD DRY GIVEN THE GFS/S PROPENSITY FOR
OVERDOING PRECIP AND THE FACT THAT NONE OF THE OTHER MODELS PRODUCE
QPF. HOWEVER...I COULD SEE A CASE FOR PRECIP TO OUR EAST AS THE
WAVE DEEPENS JUST A BIT. FOR DAY 7...MODELS ALL HINT AT YET ANOTHER
SHORTWAVE PUSHING INTO THE UPPER MIDWEST BUT LOCATION AND TIMING ARE
NOT IN AGREEMENT. A SURFACE LOW IS BEING DEPICTED BY THE MODELS BUT
WITH UPPER RIDGING PRETTY MUCH IN PLACE I AM NOT LOOKING FOR A LOT
OF MOISTURE WITH THE SYSTEM SO ONCE AGAIN I WILL KEEP THE FORECAST
DRY UNTIL THERE IS BETTER AGREEMENT WITH MODELS AND I SEE SOME KIND
OF MOISTURE WORKING INTO THE REGION. THE MAIN THING FOR THE WEEKEND
IS THAT TEMPS WILL MODERATE TO READINGS ABOVE NORMAL WITH THE UPPER
RIDGING AND SOME LOWER LEVEL WAA WORKING INTO THE REGION.
&&
.AVIATION...25/18Z
MAIN FORECAST PROBLEM IS WITH THE STRATOCU OVER NRN IA. IT WILL
ONLY AFFECT THE KFOD AND KMCW AREA EARLY IN THE PERIOD AS IT THINS
OUT. DON`T EXPECT TO SEE IT PROGRESS SWD. MID AND HIGH CLOUDS WILL
HOLD THROUGH THE NIGHT INTO MON. SOME LOWERING TONIGHT...BUT CIGS
REMAINING ABOVE 050. LIGHT NW-NLY WINDS THROUGH THE FORECAST PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...REV
LONG TERM...FAB
AVIATION...REV
AREA FORECAST DISCUSSION
NWS DES MOINES IA
521 AM CST SUN NOV 25 2012
.UPDATE 25/12Z AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
SOMEWHAT COMPLICATED SHORT TERM TODAY AS MODELS NOT HANDLING THE
CLOUD COVER OVER MINNESOTA AT ALL. RAP MODEL HAS A BETTER IDEA THAT
STRATUS HAS FORMED AND HEADING SOUTH INTO THE REGION TODAY.
MEANWHILE THERE IS AN UPPER LEVEL BOUNDARY WITH UPSLOPE CLOUDS AND
LIGHT SNOW THAT IS ALSO CREATING A SHIELD OF CLOUDS SCHEDULED TO
HEAD EAST TOWARDS US LATER TODAY. THE COMBINATION OF SOME CLOUDS
EARLY AND MORE CLOUDS LATER WILL DAMPEN HIGHS TODAY. ALSO...THE
MAIN COLD FRONT NOW OVER NORTHWEST IOWA WILL SLIDE SOUTHEAST TODAY
KEEPING NORTHERN IOWA COOLER THAN THE REST OF THE REGION. HIGHS
THERE SHOULD TOP OUT IN THE MID 30S WHILE...WITH THE HEAD START IN
THE MID 30S...CENTRAL AND SOUTHERN IOWA WILL REACH THE LOWER TO MID
40S BY THE MID AFTERNOON. SOME AREAS MAY SEE AMPLE SUN EARLY TODAY
BUT WITH THICKENING CLOUDS MOST OF THE MORNING NORTH AND WEST/SOUTH
REGIONS LATER IN THE AFTERNOON IT SHOULD BE PARTLY SUNNY AT BEST IN
MANY LOCATIONS. WINDS WILL PICK UP BEHIND THE COLD FRONT AND
INCREASE TO ABOUT 10 TO 20 MPH WITH A FEW HIGHER GUSTS BY 2 TO 4 PM
AND THEN DIMINISH BY EVENING. NO PRECIPITATION IS EXPECTED.
.LONG TERM /TONIGHT THROUGH SATURDAY/...
A ZONAL THE NORTHWEST FLOW WILL REMAIN OVER THE CENTRAL CONUS FOR
THE BULK OF THE FORECAST PERIOD. THERE WILL ALSO BE VERY LITTLE
MOISTURE AROUND. THERE ARE SEVERAL SHORTWAVES IN THE UPPER FLOW AND
A COLD FRONT EXPECTED TO CONTINUE TO PASS EAST TONIGHT WITH LITTLE
FANFARE. COLDER AIR WILL SPILL INTO CENTRAL IOWA FOR MONDAY AND
MONDAY NIGHT. A DECENT SHORTWAVE IS PROGGED BY EVERY MEDIUM RANGE
MODEL TO PASS ACROSS THE STATE VERY LATE SUNDAY NIGHT THROUGH
MONDAY. WHAT IS ALSO INTERESTING IS THAT EVERY MODEL DEEPENS THE
WAVE JUST BEFORE IS SWINGS ACROSS IOWA...PUSHING THE FORCING AND THE
PRECIP A LITTLE FURTHER SOUTH. WITH A PRETTY DRY AIRMASS IN PLACE
AND THE FORCING ROM THE SHORTWAVE NOW SHIFTING SOUTH...I EXPECT
LITTLE MORE THAN FLURRIES ACROSS THE FAR SOUTHWEST AND SOUTH.
SHOULD THIS WAVE NOT DEEPEN AS MUCH OR IF THERE IS MORE MOISTURE
WITH THIS SYSTEM THAN THE MODELS ARE SUGGESTING THEN POPS WILL NEED
TO BE RAISED BUT FOR NOW...FLURRIES WILL COVER THE THREAT.
FOR MONDAY NIGHT THROUGH WEDNESDAY AN UPPER LEVEL RIDGE TRIES TO
ESTABLISH ITSELF OVER THE INTERMOUNTAIN WEST KEEPING A NORTHWEST
FLOW ACROSS THE UPPER MIDWEST. DRY AND SEASONAL TO SLIGHTLY BELOW
NORMAL TEMPERATURES ARE EXPECTED DURING THIS TIME.
MODELS DIVERGE SOME THURSDAY NIGHT INTO THE REMAINDER OF THE
EXTENDED. THE GFS DEVELOPS ANOTHER DECENT SHORTWAVE OVER THE REGION
AND THE GEM IS A LITTLE WEAKER AND FURTHER EAST WITH THIS FEATURE
WHILE THE EURO BARELY HAS A REFLECTION IN A MAINLY ZONAL FLOW. AT
THIS TIME I WILL KEEP THIS PERIOD DRY GIVEN THE GFS/S PROPENSITY FOR
OVERDOING PRECIP AND THE FACT THAT NONE OF THE OTHER MODELS PRODUCE
QPF. HOWEVER...I COULD SEE A CASE FOR PRECIP TO OUR EAST AS THE
WAVE DEEPENS JUST A BIT. FOR DAY 7...MODELS ALL HINT AT YET ANOTHER
SHORTWAVE PUSHING INTO THE UPPER MIDWEST BUT LOCATION AND TIMING ARE
NOT IN AGREEMENT. A SURFACE LOW IS BEING DEPICTED BY THE MODELS BUT
WITH UPPER RIDGING PRETTY MUCH IN PLACE I AM NOT LOOKING FOR A LOT
OF MOISTURE WITH THE SYSTEM SO ONCE AGAIN I WILL KEEP THE FORECAST
DRY UNTIL THERE IS BETTER AGREEMENT WITH MODELS AND I SEE SOME KIND
OF MOISTURE WORKING INTO THE REGION. THE MAIN THING FOR THE WEEKEND
IS THAT TEMPS WILL MODERATE TO READINGS ABOVE NORMAL WITH THE UPPER
RIDGING AND SOME LOWER LEVEL WAA WORKING INTO THE REGION.
&&
.AVIATION...25/12Z
LOW STRATUS MOVING INTO NORTHERN IOWA THIS MORNING. SOME UNCERTAINTY
AS TO HOW FAR SOUTH THE CLOUDS WILL ADVANCE BEFORE SOME EROSION OF
LOWER CLOUDS OCCURS. HOWEVER...COLD AIR ADVECTION ACCOMPANYING CLOUD
DECK WILL PROBABLY INFLUENCE THE STRATUS AND KEEP AREAL COVERAGE
MORE INTACT AS IT HEADS SOUTH. THIS AREA OF CLOUDS WILL REDUCE CIGS
TO AN MVFR CATEGORY AS IT MOVES INTO THE REGION. FARTHER WEST
ANOTHER BAND OF CLOUDS WILL HEAD EAST TODAY INTO IOWA BRINGING CIGS
BUT STILL VFR. WINDS WILL REMAIN OUT OF THE SOUTH OR WEST OVER
SOUTHERN SITES THROUGH 16Z PRIOR TO MAIN COLD FRONT SWINGING ALL
WINDS TO NORTH DIRECTION. THIS WILL HAPPEN NORTH SITES OF KMCW KFOD
AND KALO BETWEEN 12Z TO 15Z AND FROM 16Z TO 19Z FOR KDSM AND KOTM.
CURRENT EXPECTATION IS THAT MVFR CLOUDS OVER MN WILL AFFECT KMCW
KFOD AND KALO BEFORE CIGS LIFT SOMEWHAT ON SOUTHERN EDGE. KDSM AND
KOTM SHOULD REMAIN MAINLY VFR WITH CIGS IN A GENERAL RANGE OF 100 TO
150KFT. FOR A BRIEF WINDOW BETWEEN 12Z AND 15Z THERE AN AREA OF
UNLIMITED CIGS AND VFR CONDITIONS MAY HOLD ALONG AND NEAR THE US 20
CORRIDOR BEFORE LOWER MVFR CLOUDS MOVE INTO THE AREA. AFT 20Z WINDS
WILL BEGIN TO MIX MORE ACROSS THE NORTH AS BUFR SOUNDINGS INDICATE
GUSTS TO 20KTS FOR SEVERAL HOURS PRIOR TO SUNSET. SOUTH SITES WILL
EXPERIENCE LESS INFLUENCE OF HIGHER MIXED GUSTS DUE TO LIGHTER WINDS
NEAR THE INVERSION AT KDSM AND KOTM.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...REV
LONG TERM...FAB
AVIATION...REV
AREA FORECAST DISCUSSION
NWS DES MOINES IA
315 AM CST SUN NOV 25 2012
.SHORT TERM /TODAY/...
SOMEWHAT COMPLICATED SHORT TERM TODAY AS MODELS NOT HANDLING THE
CLOUD COVER OVER MINNESOTA AT ALL. RAP MODEL HAS A BETTER IDEA THAT
STRATUS HAS FORMED AND HEADING SOUTH INTO THE REGION TODAY.
MEANWHILE THERE IS AN UPPER LEVEL BOUNDARY WITH UPSLOPE CLOUDS AND
LIGHT SNOW THAT IS ALSO CREATING A SHIELD OF CLOUDS SCHEDULED TO
HEAD EAST TOWARDS US LATER TODAY. THE COMBINATION OF SOME CLOUDS
EARLY AND MORE CLOUDS LATER WILL DAMPEN HIGHS TODAY. ALSO...THE
MAIN COLD FRONT NOW OVER NORTHWEST IOWA WILL SLIDE SOUTHEAST TODAY
KEEPING NORTHERN IOWA COOLER THAN THE REST OF THE REGION. HIGHS
THERE SHOULD TOP OUT IN THE MID 30S WHILE...WITH THE HEAD START IN
THE MID 30S...CENTRAL AND SOUTHERN IOWA WILL REACH THE LOWER TO MID
40S BY THE MID AFTERNOON. SOME AREAS MAY SEE AMPLE SUN EARLY TODAY
BUT WITH THICKENING CLOUDS MOST OF THE MORNING NORTH AND WEST/SOUTH
REGIONS LATER IN THE AFTERNOON IT SHOULD BE PARTLY SUNNY AT BEST IN
MANY LOCATIONS. WINDS WILL PICK UP BEHIND THE COLD FRONT AND
INCREASE TO ABOUT 10 TO 20 MPH WITH A FEW HIGHER GUSTS BY 2 TO 4 PM
AND THEN DIMINISH BY EVENING. NO PRECIPITATION IS EXPECTED.
.LONG TERM /TONIGHT THROUGH SATURDAY/...
A ZONAL THE NORTHWEST FLOW WILL REMAIN OVER THE CENTRAL CONUS FOR
THE BULK OF THE FORECAST PERIOD. THERE WILL ALSO BE VERY LITTLE
MOISTURE AROUND. THERE ARE SEVERAL SHORTWAVES IN THE UPPER FLOW AND
A COLD FRONT EXPECTED TO CONTINUE TO PASS EAST TONIGHT WITH LITTLE
FANFARE. COLDER AIR WILL SPILL INTO CENTRAL IOWA FOR MONDAY AND
MONDAY NIGHT. A DECENT SHORTWAVE IS PROGGED BY EVERY MEDIUM RANGE
MODEL TO PASS ACROSS THE STATE VERY LATE SUNDAY NIGHT THROUGH
MONDAY. WHAT IS ALSO INTERESTING IS THAT EVERY MODEL DEEPENS THE
WAVE JUST BEFORE IS SWINGS ACROSS IOWA...PUSHING THE FORCING AND THE
PRECIP A LITTLE FURTHER SOUTH. WITH A PRETTY DRY AIRMASS IN PLACE
AND THE FORCING ROM THE SHORTWAVE NOW SHIFTING SOUTH...I EXPECT
LITTLE MORE THAN FLURRIES ACROSS THE FAR SOUTHWEST AND SOUTH.
SHOULD THIS WAVE NOT DEEPEN AS MUCH OR IF THERE IS MORE MOISTURE
WITH THIS SYSTEM THAN THE MODELS ARE SUGGESTING THEN POPS WILL NEED
TO BE RAISED BUT FOR NOW...FLURRIES WILL COVER THE THREAT.
FOR MONDAY NIGHT THROUGH WEDNESDAY AN UPPER LEVEL RIDGE TRIES TO
ESTABLISH ITSELF OVER THE INTERMOUNTAIN WEST KEEPING A NORTHWEST
FLOW ACROSS THE UPPER MIDWEST. DRY AND SEASONAL TO SLIGHTLY BELOW
NORMAL TEMPERATURES ARE EXPECTED DURING THIS TIME.
MODELS DIVERGE SOME THURSDAY NIGHT INTO THE REMAINDER OF THE
EXTENDED. THE GFS DEVELOPS ANOTHER DECENT SHORTWAVE OVER THE REGION
AND THE GEM IS A LITTLE WEAKER AND FURTHER EAST WITH THIS FEATURE
WHILE THE EURO BARELY HAS A REFLECTION IN A MAINLY ZONAL FLOW. AT
THIS TIME I WILL KEEP THIS PERIOD DRY GIVEN THE GFS/S PROPENSITY FOR
OVERDOING PRECIP AND THE FACT THAT NONE OF THE OTHER MODELS PRODUCE
QPF. HOWEVER...I COULD SEE A CASE FOR PRECIP TO OUR EAST AS THE
WAVE DEEPENS JUST A BIT. FOR DAY 7...MODELS ALL HINT AT YET ANOTHER
SHORTWAVE PUSHING INTO THE UPPER MIDWEST BUT LOCATION AND TIMING ARE
NOT IN AGREEMENT. A SURFACE LOW IS BEING DEPICTED BY THE MODELS BUT
WITH UPPER RIDGING PRETTY MUCH IN PLACE I AM NOT LOOKING FOR A LOT
OF MOISTURE WITH THE SYSTEM SO ONCE AGAIN I WILL KEEP THE FORECAST
DRY UNTIL THERE IS BETTER AGREEMENT WITH MODELS AND I SEE SOME KIND
OF MOISTURE WORKING INTO THE REGION. THE MAIN THING FOR THE WEEKEND
IS THAT TEMPS WILL MODERATE TO READINGS ABOVE NORMAL WITH THE UPPER
RIDGING AND SOME LOWER LEVEL WAA WORKING INTO THE REGION.
&&
.AVIATION...25/06Z
BOUNDARY WILL PROGRESS THROUGH THE BOUNDARY OVERNIGHT WITH VFR
CEILINGS ACROSS MUCH OF THE STATE. HOWEVER...MVFR CIGS WILL LIKELY
CLIP THE NORTHEAST THIRD OF THE FORECAST AREA LATE TONIGHT INTO
SUNDAY MORNING AFFECTING BOTH KMCW AND KALO FOR A PERIOD OF TIME
DURING THE MORNING. BY AFTERNOON...ALL CEILINGS WILL RETURN TO VFR
WITH VISIBILITIES REMAINING UNRESTRICTED FOR THE DURATION OF THE
FORECAST. LIGHT WINDS FROM THE SOUTH WILL BE REPLACED WITH
NORTHWEST WINDS BEHIND THE BOUNDARY. THESE WINDS WILL BECOME GUSTY
ON SUNDAY AS PRESSURE GRADIENT TIGHTENS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...REV
LONG TERM...FAB
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
646 PM EST MON NOV 26 2012
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 421 PM EST MON NOV 26 2012
MAIN ITEM OF CONCERN FOR THE START OF THE SHORT TERM WILL BE THE
ONGOING LES...MAINLY OVER THE EASTERN CWA.
HIGH PRESSURE RIDGE MOVING OVER THE CWA FROM HIGH OVER THE LOWER
GREAT LAKES AND AHEAD OF A LOW APPROACHING FROM NEAR LAKE WINNIPEG
WILL ALLOW THE WINDS TO BACK TO THE WEST THIS EVENING AND THEN
WEST-SOUTHWEST DURING THE OVERNIGHT HOURS. THIS...COMBINED WITH
LOWERING INVERSION HEIGHTS THIS EVENING WILL CONTINUE TO DIMINISH
LES INTENSITY THROUGH THE EVENING OVER THE WEST. THINK THE AREA THAT
WILL HANG ONTO IT THE LONGEST WILL BE OVER NORTHERN HOUGHTON
COUNTY...UNDER INCREASED CONVERGENCE WITH THE BACKING WINDS. AS THE
WINDS CONTINUE TO BACK TO THE SOUTH WEST...HIGH RES MODELS
INDICATING A STRONGER BAND OF LAKE EFFECT SNOW BECOMING PARALLEL TO
OR RIGHT OVER THE WESTERN KEWEENAW SHORELINE FROM THE UPPER
ENTRANCE TO EAGLE HARBOR. WITH THE LOWER INVERSION AND
DRIER AIR ALOFT INITIALLY...DON/T THINK THE INTENSITY WILL BE TOO
STRONG...BUT COULD SEE A BRIEF INCREASE LATE TONIGHT AS DEEPER
MOISTURE ARRIVES AHEAD OF THE APPROACHING LOW/FRONT. IF THE
SOUTHWEST FLOW WASN/T PRODUCING AS MUCH WAA...H850 TEMPS RISING TO
-9C BY 12Z TUESDAY AND LOWERING LOW LEVEL LAPSE RATES...WOULD BE
CONCERNED ABOUT HIGHER SNOW AMOUNTS. LAKE EFFECT SNOW
PARAMETER ALSO SHOWING THIS QUICK UPTICK IN ACTIVITY LATE
TONIGHT AND THEN QUICKLY DIMINISHING TOWARDS DAYBREAK
WITH THE WAA.
AS FOR THE EAST...EXPECT NORTHWEST WIND LES...AIDED BY THE
CONVERGENCE OVER THE EASTERN LAKE FROM A SURFACE TROUGH...TO
CONTINUE OVER THE NEXT SEVERAL HOURS IN THE MUNISING TO GRAND MARAIS
AREA. MODELS SEEM TO BE STRUGGLING WITH THE STRENGTH OF THE
TROUGH...BUT THE RAP HAS HAD A DECENT HANDLE ON IT THROUGH THE
DAY...DUE TO BETTER INITIALIZATION OF LOW LEVEL WINDS...AND WILL
FOLLOW THAT FOR THE NEAR TERM. RADAR ESTIMATES OF 1-2 IN/HR
SNOW IN THAT AREA OVER THE LAST COUPLE OF HOURS AND WILL KEEP THE
LES WARNING GOING THROUGH 03Z TONIGHT. AFTER 03Z...H950-900 WINDS
BACK TO THE WEST-NORTHWEST AND START PUSH THE STRONGER BAND OFF TO
THE EAST. THIS SHOULD ACCELERATE THROUGH THE OVERNIGHT HOURS...AS
WINDS BECOME WESTERLY AND THEN WEST-SOUTHWEST LATE. STILL EXPECT
THERE TO BE SOME HEAVIER SNOW IN THIS BAND...BUT THE TRANSIENT
NATURE WILL KEEP ACCUMULATIONS LIMITED AFTER 03Z. COULD NEED A BRIEF
ADVISORY ON THE BACK SIDE OF THE WARNING FOR ALGER AND NORTHERN
SCHOOLCRAFT...BUT WITH IT QUICKLY WINDING DOWN AND SPS THIS EVENING
SHOULD COVER IT. WITH THE SNOW AMOUNTS SHOWN ON RADAR...HAVE BUMPED
UP SNOW AMOUNTS THROUGH 3Z...WITH 5-7IN BETWEEN MUNISING AND
SHINGLETON.
WEAK LOW PRESSURE SYSTEM CURRENTLY TO THE WEST OF LAKE WINNIPEG AND
ASSOCIATED COLD FRONT WILL SWEEP ACROSS WESTERN LAKE SUPERIOR LATE
TUESDAY MORNING THROUGH TUESDAY EVENING. WITH THE SOUTHWEST FLOW
IN PLACE ON TUESDAY MORNING...EXPECT THE MAIN SNOW TO BE OCCURRING
OVER WESTERN/NORTHERN LAKE SUPERIOR AND POTENTIALLY RIGHT ALONG THE
NORTHWEST SHORELINE OF KEWEENAW COUNTY. LOW-MID CLOUDS SHOULD BE
PUSHING INTO THE AREA AHEAD OF THIS SYSTEM ON TUESDAY MORNING...SO
EXPECT MUCH OF THE AREA TO BE CLOUDY...ALTHOUGH THERE COULD BE SOME
BREAKS OVER THE EAST DEPENDING ON HOW THICK THE 6-10KFT DECK IS.
WITH DECENT H850 WAA MOVING THROUGH COULD ALSO SEE SOME
ISOLATED/SCATTERED SNOW SHOWERS MOVING OVER THE WESTERN LAKE AND
FAR WESTERN UPPER MI DURING THE MORNING. THEN...WITH THE ARRIVAL OF
THE WEAK SHORTWAVE...ASSOCIATED HEIGHT FALLS...AND H850-500 Q-VECTOR
CONV AND WAA OVER THE WESTERN HALF OF THE CWA IN THE
AFTERNOON...THINK THERE WILL BE ENOUGH TO PRODUCE SCATTERED SNOW
SHOWERS OVER THE WESTERN/CENTRAL CWA DURING THE AFTERNOON. THE
STRONGEST SNOW SHOWERS WILL LIKELY BE OVER THE KEWEENAW
PENINSULA...WHERE WINDS WILL VEER DURING THE AFTERNOON AND PUSH ANY
LES BAND OVER THE WESTERN LAKE ONSHORE.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 421 PM EST MON NOV 26 2012
TUESDAY NIGHT...THE MODELS WERE IN REASONABLE AGREEMENT WITH THE
CLIPPER SHORTWAVE TROUGH INTO WRN UPPER MI AT 00Z/WED. AS THE SHRTWV
AND ASSOCIATED COLD FRONT MOVES THROUGH...WINDS WILL VEER FROM SW TO
NW. WITH FAVORABLE 850-700 MB MOISTURE...850 MB TEMPS AROUND
-11C...AND LOW LEVEL CONVERGENCE NEAR THE FRONT ..EXPECT A PERIOD OF
MODERATE TO HEAVY LAKE EFFECT SNOW TO MOVE THROUGH THE WEST IN THE
EVENING AND THEN FOCUS MAINLY OVER THE NE CWA LATE WED NIGHT.
SNOWFALL AMOUNTS MAY APPROACH ADVY CRITERIA OF AROUND 4 INCHES...IN
HIGHER TERRAIN OVER THE WEST SOUTH OF HOUGHTON AND OVER EASTERN
ALGER INTO NRN LUCE COUNTIES.
WEDNESDAY...THE LES SHOULD DIMINISH FROM WEST TO EAST AS A SFC RIDGE
BUILDS INTO THE AREA WITH BACKING WINDS AND DROPPING INVERSION
HEIGHTS. THE BEST CHANCE FOR SIGNIFICANT ACCUMULATIONS WILL REMAIN
OVER THE FAR NE CWA IN THE MORNING (NE LUCE COUNTY) WHERE THE HIGHER
RES MODELS INDICATE POTENTIAL FOR GREATEST LOW LEVEL CONV WITH
300-310 FLOW.
WED NIGHT INTO THU...AS A SHRTWV MOVES THROUGH NRN ONTARIO AND HIGH
PRES BUILDS FROM NRN ALBERTA AND SASK INTO NRN ONTARIO...ANOTHER
WEAK COLD FRONT WILL DROP THROUGH THE NRN GREAT LAKES. BEHIND THE
FRONT...WINDS ARE EXPECTED TO VEER TO THE NORTHEAST. WITH ONLY
SHALLOW COLD AIR MASS AND DRY ACYC FLOW INTO THE AREA...ONLY SLIGHT
CHANCE POPS WERE INCLUDED FOR -SHSN LATE WED NIGHT INTO THU MORNING
OVER MAINLY N CNTRL UPPER MI.
FRIDAY THROUGH MONDAY...THE MODELS WERE IN GENERAL AGREEMENT WITH A
TRANSITION TO A MORE ZONAL PATTERN BRINGING MILD PACIFIC AIR INTO
THE REGION. AS WAA AND MOISTURE ADVECTION INCREASES FRIDAY...ENOUGH
COLD AIR IS EXPECTED TO LINGER SO THAT MAINLY -SN WOULD BE EXPECTED
WITH ANY LIGHT PCPN. THE ECMWF WAS STRONGER/SLOWER WITH A SHORTWAVE
RESULTING IN A MORE PRONOUNCED WARM/MOIST SURGE SATURDAY COMPARED TO
THE GFS/GEM. FOLLOWING THE RAIN CHANCES SAT...MOIST/MILD AIR IS
EXPECTED TO LINGER INTO EARLY NEXT WEEK WHEN ADDITIONAL RAIN CHANCES
ARE POSSIBLE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 645 PM EST MON NOV 26 2012
WITH WINDS BACKING MORE TOWARD THE SW...LAKE EFFECT HAS ENDED AT
KIWD. EXPECT VFR CONDITIONS TO PREVAIL THERE THRU THIS FCST PERIOD
THOUGH THERE MAY BE SOME FLURRIES/-SN AT TIMES DURING THE DAY TUE.
AT KCMX...LAKE EFFECT SHSN WILL CONTINUE THRU THE EVENING WITH MVFR
CONDITIONS GENERALLY PREVAILING. MAY SEE SOME BRIEF PERIODS OF
IFR...BUT IFR SHOULD BE MORE LIKELY LATE EVENING/EARLY PART OF THE
OVERNIGHT AS BACKING WINDS OVER THE LAKE SHOULD RESULT IN AN AREA OF
ENHANCED CONVERGENCE/SOMEWHAT HEAVIER SHSN THAT WILL SHIFT N ACROSS
THE KEWEENAW. CONVERGENCE BAND SHOULD SHIFT N OF KCMX LATER IN THE
NIGHT WITH VFR CONDITIONS FOLLOWING. AN APPROACHING LOW PRESSURE
SYSTEM AND WEAK FRONT WILL REACH WRN LAKE SUPERIOR TUESDAY...LEADING
TO INCREASING POTENTIAL OF SHSN/MVFR CONDITIONS IN THE AFTN. AT
KSAW...VFR CONDITIONS WILL PREVAIL THRU THE FCST PERIOD AS WINDS
WILL BE UNFAVORABLE FOR LAKE EFFECT SHSN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 PM EST MON NOV 26 2012
WITH GENERALLY WEAK CLIPPER SYSTEMS BEING THE MAIN WIND PRODUCERS
OVER THE NEXT FEW DAYS...WINDS OF 20 TO 30 KTS WILL BE COMMON BUT NO
GALES ARE EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 10 PM EST THIS EVENING FOR MIZ006-
085.
LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST TUESDAY FOR MIZ007.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
430 PM EST SUN NOV 25 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 428 PM EST SUN NOV 25 2012
WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW
THROUGH THE NRN CONUS. A SHORTWAVE TROUGH EXTENDED FROM NRN ONTARIO
(NEAR CYGQ) INTO NRN WI. A WEAKER UPSTREAM SHRTWV WAS LOCATED OVER
SW MANITOBA. AT THE SFC...LOW PRES WAS LOCATED JUST NORTHEAST OF
LAKE SUPERIOR RESULTING IN WNW LOW LEVEL WINDS. CYCLONIC FLOW AND
ABUNDANT 850-700 MB MOISTURE IN THE WAKE OF THE LOW ALONG WITH 850
MB TEMPS IN THE -11C TO -14C RANGE SUPPORTED AN INCREASE IN LES BAND
INTENSITY. THE STRONGEST BANDS WERE LOCATED NEAR HOUGHTON AND INTO THE
ERN CWA JUST TO THE EAST OF MUNISING.
MAIN FCST CONCERNS ARE LES TRENDS.
EXPECT LES TO CONTINUE FOR LOCATIONS FAVORED BY A 290-310
FLOW...INCLUDING MOST OF THE WRN CWA AND LOCATIONS FROM MUNISING
EASTWARD. THE HIGH RES MODELS IN AGREEMENT SHOWING A GRADUAL
VEERING TREND THIS EVENING WHICH SHOULD HELP TO KEEP THE BANDS FOR
IMPACTING NARROW AREAS FOR AN EXTENDED PERIOD OF TIME. THIS SHOULD
ALSO RESULT IN DECREASING LES INTENSITY INTO THE KEWEENAW WITH A LES
FAVORABLE NW FETCH.
THE HIGH RES MODELS WERE ALSO CONSISTENT IN SHOWING A MORE PRONOUNCED
LOW LEVEL CONV ZONE AIDED BY LAKE INDUCED TROUGHING OVER ERN LAKE
SUPERIOR. THIS SHOULD PROVIDE THE FOCUS FOR THE HEAVIES LES LATE
TONIGHT INTO MONDAY AFTERNOON FOR EASTER ALGER AND NORTHWEST
SCHOOLCRAFT COUNTIES.
INVERSION HEIGHTS IN THE 5K TO 7K FOOT RANGE...GREATEST EAST...ALONG
WITH A DEEP PORTION OF THE CONVECTIVE CLOUDS IN THE DENDRITIC GROWTH
ZONE SHOULD KEEP SNOW/WATER RATIOS IN THE HIGHER SIDE...AT OR ABOVE
20/1. OVERALL SNOWFALL AMOUNTS IN THE 6 TO 12 INCH RANGE STILL LOOK
POSSIBLE FOR SOME LOCATIONS IN ALGER/NSCHOOLCRAFT ZONES WHILE 3 TO 7
INCH AMOUNTS ARE MORE LIKELY OVER THE WEST...GREATEST IN THE HIGHER
TERRAIN BTWN HOUGHTON AND BERGLAND. WITH INVERSION HEIGHTS BEGIN
LOWERING FROM WEST TO EAST MONDAY PREVIOUS FCST TIMING WHICH ENDS
THE LES ADVY OVER THE WEST AT 10 AM LOOKS ON TRACK.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 428 PM EST SUN NOV 25 2012
MON NGT...AS A HI PRES RDG AXIS EXTENDING NEWD FM THE ACYC CENTER IN
THE CENTRAL PLAINS APRCHS...THE LLVL FLOW WL SHIFT STEADILY TO A
MORE WSW DIRECTION. WITH THIS BACKING FLOW...SOME HEAVIER SHSN MIGHT
IMPACT THE KEWEENAW FOR A TIME...BUT LIMITED RESIDENCE TIME WITH
STEADILY SHIFTING WINDS AS WELL AS LOWERING INVRN BASE/WARMING H85
TEMPS SHOULD LIMIT OVERALL ACCUMS. OVER THE E...LLVL CNVGC/LES
INTENSITY MIGHT SHARPEN FOR A TIME WITH BACKING LARGER SCALE
FLOW/LAND BREEZE ENHANCED BY NOCTURNAL COOLING OVER THE CENTRAL
CWA...BUT LES BANDS SHOULD SHIFT OFFSHORE BY 12Z TUE. ALTHOUGH SOME
HEAVIER LES MAY LINGER NEAR THE SHORE FM GRAND MARAIS TO WHITEFISH
POINT LONGER THAN THE 03Z EXPIRATION TIME OF THE GOING LES WARNING
FOR ALGER COUNTY...DID NOT MAKE ANY CHANGES TO THE WARNING NOW TO
AVOID POTENTIAL VERIFICATION PENALTY. ALTHOUGH THE BACKING FLOW WL
ADVECT MORE UNMODIFIED COLD AIR INTO THE CWA...INCRSG WAD CLD IN
ADVANCE OF NEXT CLIPPER DISTURBANCE DIGGING SEWD TOWARD THE UPR LKS
WL TEND TO LIMIT THE DIURNAL TEMP FALL SOMEWHAT.
TUE...COLD FNT ASSOCIATED WITH THIS INCOMING CLIPPER SHRTWV/SFC LO
MOVING THRU NW ONTARIO IS PROGGED TO REACH THE WRN CWA BY 00Z WED.
PCPN IN ADVANCE OF THIS FNT WL BE LIMITED BY LLVL DRY AIR/ABSENCE OF
SGNFT MSTR INFLOW...BUT SUSPECT A PERIOD OF HEAVIER SHSN MIGHT
IMPACT THE W LATER IN THE DAY WITH SOME ENHANCEMENT OFF LK SUP IN
LLVL W FLOW WITH H85 TEMPS ARND -10C UNDER DPVA/DEEP LYR QVECTOR
CNVGC. NO MORE THAN CHC POPS WL BE APPROPRIATE OVER THE REST OF THE
CWA EXCEPT FOR THE E...WHERE SOME MOISTENING OF THE LLVLS IN SW FLOW
OFF LK MI WITH SUFFICIENTLY COLD AIR TO GENERATE LES MIGHT RESULT IN
SOME SHSN. GOING FCST DRY WX FOR THE FAR SCENTRAL SEEMS ON TRACK.
TUE NGT/WED...THE COLD FNT IS FCST TO SWING THRU THE UPR LKS AND
USHER IN A VERY CHILLY AIRMASS WITH H85 TEMPS AS LO AS -16C BY 12Z
WED. DESPITE THIS INCOMING CHILL...LES IN THE WAKE OF THE FROPA WL
BE STUNTED SOMEWHAT BY FAIRLY QUICK TRANSITION TO GENERAL ACYC FLOW
UNDER SHARP NVA/DEEP LYR QVECTOR DVGC/SUBSIDENCE THAT IS FCST TO
LOWER INVRN BASE OVER THE W TO BTWN 3-4K FT AGL BY 12Z WED. DESPITE
THESE NEGATIVES...OPTED TO GO WITH LIKELY POPS IN THE FAVORED NW
WIND SN BELTS...ESPECIALLY OVER THE E WITH LONGER FETCH AND SOME LK
NIPIGON PRE MOISTENING...GIVEN SUFFICIENT COLD AIR INFLUX/LK-H85
DELTA T APRCHG 20C. ON WED...THE LES IN THE NW WIND SN BELTS WL
DIMINISH WITH ARRIVAL OF SFC RDG AXIS/LOWERING INVRN BASE TO 2-3K FT
AGL/BACKING LLVL WINDS TOWARD THE W-SW.
EXTENDED...LONGER RANGE MODELS REMAIN VERY CONSISTENT SHOWING A
MAJOR PATTERN CHG LATER THIS COMING WEEK THAT WL FEATURE A ZONAL
FLOW OF UNSEASONABLY WARM PACIFIC AIR NEXT WEEKEND AS TROF IN ERN
CANADA LIFTS TO THE NE. ON THU...COLD CNDN HI PRES OVER ONTARIO
UNDER WNW FLOW ALF WL STILL BE DOMINATING THE UPR LKS...BUT
STRENGTHENING ISENTROPIC ASCENT ASSOCIATED WITH OVERRUNNING OF THE
RETREATING ARCTIC AIRMASS WL RESULT IN INCRSG CLDS TO THE NE OF WARM
FGEN IN THE NRN PLAINS TO LOWER LKS. AFTER THU...SOME VARIANCE
CREEPS INTO THE MODEL BLEND. RECENT ECMWF RUNS HAVE BEEN VERY
CONSISTENT INDICATING SOME -SN MAY DVLP ON THU NGT AND FRI AS THE
WARM FNT MOVES TO THE N. THE ECMWF INDICATES PCPN MAY EVEN
TRANSITION TO SOME -FZDZ AS DEEPER MSTR SHIFTS TO THE N AS LINGERING
NEAR SFC COLD AIR BECOMES SHALLOWER WITH LOWERING WARM FRONTAL INVRN
HGT. ON THE OTHER HAND...THE MAJORITY OF RECENT GFS RUNS SHOW THE
WARM FNT REMAINING FARTHER S AS A WAVE OF LO PRES ASSOCIATED WITH A
STRONGER SHRTWV RIPPLING THRU THE UPR MIDWEST RUNS W-E ALONG THIS
BNDRY. GIVEN THE LARGER SCALE TRENDS TOWARD RISING HGTS IN THE GRT
LKS AND CONSISTENCY OF THE ECMWF...WHICH IS ALSO PREFERRED BY
NCEP...TENDED TO USE THE ECMWF AS A GUIDE FOR PTYPE DURING THIS
TIME. BULK OF MODELS SHOW ANOTHER SHRTWV WL APRCH ON SAT. IF THE
ECMWF IS CORRECT...PCPN SHOULD BE MAINLY RA. ONLY MARITIME POLAR AIR
WL FOLLOW THIS DISTURBANCE FOR SUN UNDER THE ZONAL FLOW ALF...SO ANY
LES ON SUN SHOULD BE MINIMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1242 PM EST SUN NOV 25 2012
MAINLY MVFR CIGS ARE EXPECTED TO PREVAIL THROUGH THE FORECAST PERIOD.
ARRIVAL OF COLDER AIR WILL GENERATE MORE LAKE EFFECT -SHSN THIS
AFTERNOON AND EVENING AT KIWD AND ESPECIALLY AT KCMX WHERE THE
EXPECTED W WIND WILL UPSLOPE. ON THE OTHER HAND...VFR VSBY SHOULD
CONTINUE AT KSAW WITH DOWNSLOPE WIND COMPONENT. AS INCREASINGLY
COLDER AIR MOVES INTO THE UPPER LAKES...LAKE EFFECT -SHSN SHOULD
BECOME HEAVIER AT KIWD AND KCMX LATE AFTN THROUGH TONIGHT WITH IFR
VIS EXPECTED.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 428 PM EST SUN NOV 25 2012
EXPECT NW WINDS TO 30 KTS TONIGHT AS LOW PRESSURE JUST NORTHEAST OF
LAKE SUPERIOR MOVES QUICKLY OFF TO THE EAST. THERE MAY ALSO BE A FEW
GALE GUSTS TO 35 KTS TONIGHT OVER NORTHERN AND EASTERN PORTIONS OF
LK SUPERIOR. WINDS WILL DIMINISH TO 15 TO 25 KT MONDAY AS HIGH
PRESSURE BUILDS INTO THE UPPER MS VALLEY AND THE WESTERN GREAT
LAKES.
AS HI PRES RIDGE MOVES THRU THE UPPER GREAT LAKES ON MON NIGHT...
EXPECT DIMINISHING WINDS BACKING TO THE SW. THIS SW WIND WILL
INCREASE UP TO 25 TO 30 KTS ON TUE AHEAD OF AN APPROACHING COLD
FRONT. FOLLOWING THE FRONTAL PASSAGE ON LATE TUE/TUE NIGHT...PLAN ON
A WIND SHIFT TO THE NW UP TO 30 KTS AS MUCH COLDER AIR MOVES OVER
LAKE SUPERIOR AND ENHANCES MIXING OF THE STRONGER WINDS TO THE
SURFACE. THE APPROACH OF ANOTHER HI PRES WILL BRING DIMINISHING
WINDS FOR WED. WITH RELATIVELY WEAK PRES GRADIENT IN PLACE THEN FOR
THU/FRI...WINDS SHOULD BE UNDER 25 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 10 PM EST MONDAY FOR MIZ006-085.
LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST TUESDAY FOR MIZ007.
LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST /9 AM CST/ MONDAY FOR
MIZ002-003-009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KC
AVIATION...JLB
MARINE...JLB/KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1233 AM EST SUN NOV 25 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 350 PM EST SAT NOV 24 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER
THE GRT LKS BTWN TROF OVER ERN NAMERICA AND A RDG OVER THE ROCKIES.
RIGHT NOW...THERE IS A SHRTWV RDG ALF DOMINATING THE UPR LKS...WITH
SFC HI PRES RDG AXIS STRETCHING FM NOW ONTARIO S INTO THE UPPER
MIDWEST. DESPITE THE APRCH OF THIS RDG AXIS AND LO INVRN BASE SHOWN
ON THE 12Z INL/MPX RAOBS THAT HAS ALLOWED AT LEAST PARTIAL CLEARING
OF LO CLDS OVER MN...THE SC OVER THE CWA HAS BEEN QUITE RESILIENT
WITH H925-85 THERMAL TROF /H85 TEMPS IN THE -12C TO -15C RANGE/
UNDER HIER INVRNS H85-5 AS SHOWN ON THE 12Z GRB/APX RAOBS IN THE
LLVL NW FLOW E OF THE INCOMING SFC HI PRES RDG. THESE LO CLDS ARE
TENDING TO BREAK UP MORE AGGRESSIVELY OVER THE FAR SCENTRAL CWA WITH
DOWNSLOPE NATURE OF THE LLVL FLOW. ALTHOUGH LOWERING SUBSIDENCE
INVRN HAS TENDED TO CAUSE THE LES IN THE CHILLY NW FLOW TO DIMINISH
WITH TIME...THE SHSN HAVE BEEN MOST PERSISTENT NEAR MUNISING WITH
UPSTREAM MOISTENING OFF LK NIPIGON AND MORE LLVL CNVGC ENHANCING THE
LES IN THAT AREA. LOOKING TO THE W...SKIES ARE PCLDY CLOSE TO THE
SFC RDG AXIS...BUT THICKER CLDS ASSOCIATED WITH WAD IN THE SSW FLOW
AHEAD OF ANOTHER SHRTWV NEAR LK WINNIPEG THAT HAS BEEN RIDING OVER
THE ROCKIES RDG ARE MOVING STEADILY TO THE E INTO ERN MN THIS AFTN.
SOME -SN HAS MOVED INTO NW MN THIS AFTN UNDER DEEP ISENTROPIC
ASCENT/SOME UPR DVGC IN THE EXIT REGION OF 120KT H3 JET MAX
SUPPORTING THE SHRTWV.
MAIN FCST CONCERNS THRU SUN INCLUDE TIMING OF SN AND PCPN AMOUNTS
TNGT IN ADVANCE OF CLIPPER TYPE SHRTWV NEAR LK WINNIPEG AND THEN
TRANSITION TO LES ON SUN IN ITS WAKE.
TNGT...AS SFC HI PRES RDG SHIFTS TO THE ERN GRT LKS...EXPECT SW
FLOW/ISENTROPIC ASCENT BTWN DEPARTING RDG AND SHRTWV NEAR LK
WINNIPEG TRACKING TO THE ESE ACRS ONTARIO TO DOMINATE. SINCE THE
MAIN PV ANOMALY WL BE PASSING TO THE N...SHARPER ISENTROPIC ASCENT
BEST SHOWN ON THE 280-290K SFCS /H8-65/ WL BE TRANSIENT AS WARM
CONVEYOR BELT MSTR AXIS SWINGS THRU THE UPR LKS AHEAD OF DRY
SLOTTING ON THE SRN FLANK OF PV ANOMALY TRACK. -SN SHOULD ARRIVE
OVER THE W IN THE EVNG AND PUSH TO ERY AFTER 06Z...WHEN THE PCPN WL
BEGIN TO DIMINISH W-E FOLLOWING THE SHIFT OF THE WARM CONVEYOR BELT
RIBBON TO THE E. PCPN CHCS WL BE ENHANCED BY RIBBON OF H85-7 FGEN...
SOME UPR DVGC IN LEFT EXIT REGION OF H3 JET MAX SUPPORTING THE
ONTARIO SHRTWV...AND SOME DPVA ASSOCIATED WITH ANOTHER SHRTWV
TRACKING THRU THE UPR MIDWEST ON THE SRN FLANK OF THE MAIN PV
ANOMALY. GIVEN FCST H7 SPECIFIC HUMIDITY UP TO 2 G/KG AND A 3-6 HR
PERIOD OF -SN WITH TRANSIENT WARM CONVEYOR BELT/DEEP ASCENT...LOOKS
LIKE 1 TO 2 INCHES OF SN IS LIKELY WITH DECENT OMEGA IN THE DGZ. 12Z
GUIDANCE SHOWS THE SHARPER ISENTROPIC ASCENT/FGEN IMPACTING THE WI
BORDER AREA WITH HIER QPF/SN AMOUNTS ARND 2 INCHES MOST LIKELY
THERE. SOME OF THE MODELS ALSO HINT THERE COULD BE SOME LK
ENHANCEMENT OFF LK MI...BUT THE H925 WINDS LOOK TO BACK TO A MORE
FAVORABLE SW DIRECTION ONLY BRIEFLY TO ALLOW FOR TOO MUCH
ENHANCEMENT AT ISQ-ERY. WITH RELATIVELY QUICK ARRIVAL OF THICKER
CLDS/WAD THIS EVNG...EXPECT NEAR STEADY TEMPS MUCH OF THE NGT AFTER
EARLY MODEST DIURNAL TEMP FALL.
SUN...LINGERING -SN OVER THE E WL END SOON AFTER 12Z FOLLOWING EXIT
OF WARM CONVEYOR BELT MSTR RIBBON TO THE E AND ARRIVAL OF DRY
SLOTTING. HOWEVER...12Z MODELS HAVE TENDED TO DIG THE PV ANOMALY
MORE TO THE ESE OVER NE LK SUP DURING THE DAY. SO AS THE DAY GOES
ON...A COLD CYC NW FLOW WL DVLP IN THE WAKE OF COLD FROPA AS
ASSOCIATED SFC LO SHIFTS TO JUST E OF LK SUP BY 00Z MON. AT THE SAME
TIME...AN AXIS OF SHARPER QVECTOR CNVGC/DPVA AND SOME DEEPER MSTR WL
IMPACT MAINLY THE NE HALF OF THE FA CLOSER TO THE TRACK OF THE
SHRTWV. WITH H85 TEMPS PROGGED TO FALL AS LO AS -15C OVER THE W HALF
OF LK SUP IN THE AFTN...EXPECT MORE WDSPRD LES TO DEVELOP IN THAT
AREA. ALSO BUMPED UP POPS OVER THE NE IN THE AFTN ESPECIALLY NEAR LK
SUP GIVEN FAVORABLE ALIGNMENT OF ONSHORE WNW FLOW...DEEPER MSTR/
DPVA/QVECTOR CNVGC...AND COOLING. THE DAY SHOULD BE DRY OVER THE
SCENTRAL WITH DOWNSLOPE FLOW IN THE ABSENCE OF ANY DYNAMIC
SUPPORT/DEEP MSTR THERE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 350 PM EST SAT NOV 24 2012
THE MAIN FOCUS IN THE LONG TERM REVOLVES AROUND THE CHANCE FOR
MODERATE LAKE EFFECT SNOW ACCUMULATION EAST NEAR LAKE SUPERIOR
LATE SUNDAY NIGHT THROUGH MONDAY. EXACT LOCATIONS OF THIS POTENTIAL
ARE STILL UNCERTAIN...THOUGH THE MAIN THREAT APPEARS TO BE IN ALGER
COUNTY FROM MUNISING TO GRAND MARAIS AND SOUTH INTO NORTHERN
SCHOOLCRAFT COUNTY. ANOTHER ROUND OF LIGHT SNOW VERY SIMILAR TO
TONIGHTS SYSTEM WILL MOVE THROUGH THE AREA TUESDAY NIGHT. MILDER
PATTERN CHANGES WILL THEN BE IN THE MAKING TOWARD THE END OF THE
WEEK.
SUNDAY NIGHT THROUGH MONDAY NIGHT...THE SHORTWAVE TROUGH ASSOCIATED
WITH THE CLIPPER SYSTEM NOTED IN THE SHORT TERM WILL BE CROSSING
NORTH-CENTRAL LAKE SUPERIOR AND WESTERN UPPER MI AT THE START OF THE
PERIOD. THE ECMWF AND REGIONAL GEM HAVE BEEN QUICKER WITH THE
SHORTWAVE WITH EACH PROGRESSIVE RUN...AND HAVE COME IN LINE WITH THE
GFS AND NAM SOLUTIONS. TRENDS FROM BOTH THE GFS AND ECMWF ARE TO ADD
SUBTLE AMPLIFICATION TO THE WNW FLOW IN THE MID-LEVELS OVER THE
GREAT LAKES...WHILE THE REGIONAL GEM HAS TRENDED TO A LESS AMPLIFIED
FLOW. PREFER THE IDEA PRESENTED BY THE GFS/ECMWF AS THE NICE SHOT OF
CAA BEHIND THE LOW-LEVEL CLIPPER WILL LIKELY ADD SOME AMPLIFICATION
TO THE MID-LEVEL TROUGHING.
LINGERING LIGHT SNOW FROM THE CLIPPER WILL BE ENDING ACROSS THE
EASTERN PORTION OF THE CWA AT 00Z MONDAY AS THE LOW DEPARTS INTO SE
ONTARIO. CAA IMMEDIATELY BEHIND THE SYSTEM IS NOT ALL THAT
IMPRESSIVE...WITH H8 TEMPS ONLY AROUND -10C OVER EASTERN LAKE
SUPERIOR AT 06Z MONDAY. HOWEVER...H8 TEMPS BEGIN TO FALL FOR THE
WESTERN HALF...REACHING -14C BY 06Z MONDAY. AT THE SAME TIME...A
WEAK RIDGE BETWEEN THE DEPARTING TROUGH AND INCOMING AMPLIFYING
TROUGH WILL BE PASSING OVERHEAD AND LIKELY DISRUPT THE LOW-LEVEL
SURFACE FLOW. WHAT MAKES THIS CONCERNING IS THAT SFC TO H8 FLOW FROM
THE NW WOULD PUT A DOMINANT LES BAND INTO FAR EASTERN ALGER COUNTY
BEGINNING SUNDAY EVENING...WHILE A BACKING OF THE FLOW BEHIND THE
SUBTLE RIDGE WOULD TEMPORARILY PUSH THE BAND ALONG THE SHORE. STILL
BEING TWO DAYS OUT...THE CONNECTION BETWEEN THE MID-LEVEL FLOW AND
SFC LES SET-UP IS SOMEWHAT UNCLEAR...BUT WOULD NOT BE SURPRISED IF
THE BAND WOBBLES BETWEEN EASTERN ALGER COUNTY AND NORTHERN LUCE
COUNTY ON EARLY MONDAY MORNING. THEN...THE SECONDARY TROUGH WILL AID
LES INTENSITY ACROSS THE WHOLE NORTH SHORE OF UPPER MI LATER MONDAY
MORNING INTO THE AFTERNOON. THIS WILL OCCUR AS THE BEST CAA AND
COLDEST H8 TEMPS...AROUND -15 TO -16C...WILL BE MOVING OVER THE
LAKE. ADDITIONALLY...LAKE-INDUCED EQUILIBRIUM VALUES BASED OFF OF A
CONSERVATIVE LAKE WATER TEMPERATURE OF 5C WILL BE UPWARDS OF 7KFT
ACROSS THE WEST AND 9KFT FOR THE EAST. FINALLY...THE DGZ WILL BE
LOCATED IN THE HIGHEST 3KFT OF THE CONVECTIVE LAYER IN THE
EAST...LEADING TO THE POTENTIAL FOR INCREASED AGGREGATION FROM
DENDRITES AND THUS HIGHER SNOW RATIOS OF ABOUT 20 TO 1.
THEREFORE...EXPECT THE HIGHEST LES INTENSITY MONDAY MORNING INTO
EARLY AFTERNOON OVER THE EAST NEAR LAKE SUPERIOR.
THE NAM...GEM...AND LOCAL WRF ALL HAVE A DOMINANT BAND WITH
SIGNIFICANT LES FOR CENTRAL ALGER AND NORTHERN SCHOOLCRAFT COUNTY. A
BLEND OF NAM AND LOCAL WRF QPF RESULTED IN ACCUMULATIONS OF 6-10
INCHES CENTERED OVER MELSTRAND. ONLY USED THIS BLEND TO SEE
POTENTIAL AND WILL USE A MORE CONSERVATIVE APPROACH GIVEN THE
UNCERTAINTY OF BAND PLACEMENT. NEEDLESS TO SAY...HEADLINES MAY BE
NEEDED IF HI-RES MODELS REMAIN CONSISTENT WITH LES BAND PLACEMENT.
DRY AIR ADVECTION FROM THE SOUTHWEST IN THE LOW LEVELS...AND H8 WAA
OVERNIGHT MONDAY WILL BEGIN TO ERODE LES FROM WEST TO EAST ACROSS
THE CWA. INVERSION HEIGHTS WILL ALSO CRASH FROM AROUND 9KFT 00Z
TUESDAY TO <5KFT BY 09Z TUESDAY. MEANWHILE WINDS WILL BEGIN BACKING
AND SHOULD PUSH REMAINING LES OFFSHORE...WITH LITTLE ACTIVITY
REMAINING BY TUESDAY MORNING.
TUESDAY THROUGH WEDNESDAY...ANOTHER SHORTWAVE TROUGH DIGGING ESE OUT
OF CANADA WILL IMPACT THE CWA BY TUESDAY AFTERNOON AND BRING A ROUND
OF LIGHT SNOW TO MAINLY THE NORTHERN CWA. THE BEST UPPER LEVEL PV
ANOMALY AND MID-LEVEL Q-VECTOR DIVERGENCE ARE PROGGED TO MOVE
THROUGH TUESDAY AFTERNOON AND EVENING. THE LEFT EXIT OF A 120KT NW
TO SE ORIENTED UPPER JET WILL BE TRACKING ACROSS CENTRAL WI...SO
BEST FEATURES DO NOT QUITE LINE UP. THE LOWEST LEVELS WILL BE DRY
ENOUGH TO THE SOUTH TO PREVENT INITIAL PRECIP FROM REACHING THE
GROUND. DID NOT MAKE MANY CHANGES TO THE PREVIOUS FORECAST OTHER
THAN INCREASE POPS SLIGHTLY FOR THE ENTIRE CWA. THE TROUGH AXIS WILL
THEN PASS THROUGH THE CWA BY 12Z WEDNESDAY AND USHER IN
ANOTHER...YET SHORT-LIVED AND WEAKER...LES EVENT. INVERSION HEIGHTS
COLLAPSE QUITE QUICKLY TO ABOUT 4KFT BY WEDNESDAY AFTERNOON...AND
THE AIR BEHIND THIS SYSTEM IS CONSIDERABLY DRY THROUGHOUT THE
COLUMN. THEREFORE...EXPECTATION IS THAT THERE WILL BE A QUICK LES
EVENT WEDNESDAY MORNING INTO EARLY AFTERNOON FOR THE NW
SNOWBELTS...MAINLY ACROSS THE KEWEENAW PENINSULA AND EAST OF
MUNISING WHERE MOISTURE IS MORE ABUNDANT.
WEDNESDAY NIGHT THROUGH SATURDAY...THE PATTERN TURNS QUIET FOR MUCH
OF THE UPPER GREAT LAKES FOR THE SECOND HALF OF THE WEEK. OTHER THAN
SOME LIGHT LES POSSIBLE EAST NEAR LAKE SUPERIOR ON THURSDAY
NIGHT...NO REAL SIGNIFICANT PRECIP CHANCES PRESENT THEMSELVES AS THE
MAIN ENERGY REMAINS SOUTH OF THE CWA WITH AN UPPER LEVEL DISTURBANCE
MOVING ACROSS THE MID MISSISSIPPI VALLEY ON FRIDAY. THOUGH ON THE
EDGE OF THE FORECAST PERIOD...A STRONG RIDGE WITHIN PACIFIC FLOW
LOOKS TO BRING WELL-ABOVE AVERAGE TEMPS TO BEGIN DECEMBER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1232 AM EST SUN NOV 25 2012
CLIPPER TYPE LOW PRES SYSTEM IS CURRENTLY BRINGING -SN TO
KIWD/KCMX/KSAW WITH IFR VIS GENERALLY PREVAILING. ALTHOUGH -SN WILL
END FROM W TO E OVER THE NEXT SEVERAL HRS...EXPECT LINGERING MVFR
CIGS WITH RESIDUAL LOW-LEVEL MOISTURE. ARRIVAL OF COLDER AIR WILL
GENERATE MORE LAKE EFFECT -SHSN THIS MORNING AT KIWD AND ESPECIALLY
AT KCMX WHERE THE EXPECTED W WIND WILL UPSLOPE. ON THE OTHER HAND...
CONDITIONS ARE LIKELY TO TREND TO VFR AT KSAW WITH DOWNSLOPE WIND
COMPONENT. AS INCREASINGLY COLDER AIR MOVES INTO THE UPPER LAKES...
LAKE EFFECT -SHSN SHOULD BECOME HEAVIER AT KIWD/KCMX LATE AFTN INTO
THE EVENING WITH IFR VIS BECOMING MORE LIKELY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 350 PM EST SAT NOV 24 2012
EXPECT S-SW WINDS UP TO 20 KTS IN ADVANCE OF A CLIPPER SYSTEM
TONIGHT TO VEER TO THE WNW ON SUN AS THE LO MOVES TO THE E OF LAKE
SUP AND DRAGS A COLD FRONT ACROSS THE AREA.
NORTHWEST WINDS OF 20 TO 30 KNOTS DUE TO HIGH PRESSURE QUICKLY
IMPINGING ON A DEPARTING LOW OVER FAR EASTERN UPPER MICHIGAN WILL BE
POSSIBLE SUNDAY NIGHT...WITH EVEN A FEW GALE FORCE GUSTS UP TO 35
KNOTS NOT OUT OF THE QUESTION. EXPECT THESE WINDS TO QUICKLY
DECREASE ON MONDAY AS A HIGH PRESSURE RIDGE SETTLES OVER THE UPPER
GREAT LAKES. SOUTHWEST WINDS OF 20 TO 25 KNOTS WILL THEN BE
POSSIBLE...MAINLY FOR THE WEST HALF OF LAKE SUPERIOR ON TUESDAY
AHEAD OF A COLD FRONT. ONCE THE FRONT PASSES TUESDAY AFTERNOON AND
EVENING...WINDS WILL VEER TO THE W/NW AND INCREASE TO 20 TO 25 KNOTS
FOR THE EAST HALF OF THE LAKE THROUGH WEDNESDAY. EXPECT WINDS TO
REMAIN BELOW 20 KNOTS FOR THE REMAINDER OF THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KLUBER
AVIATION...ROLFSON
MARINE...KC/KLUBER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
101 PM CST SUN NOV 25 2012
.UPDATE...
MINOR UPDATES TO THE FORECAST EARLIER TODAY TO ADJUSTED
TEMPERATURES DOWNWARD IN THE NORTH AND ACCOUNT FOR MORE CLOUDS
EARLY ON IN THE SOUTH.
&&
.DISCUSSION...
A COUPLE OF SHORTWAVES WILL AFFECT THE FORECAST AREA TODAY AND
TONIGHT. THE STRONGER THETA-E ADVECTION AND PERSISTENT WEAK LIFT
IS RESULTING CLOUDS FOR NORTHCENTRAL INTO EASTERN NEBRASKA AND
WESTERN IOWA. WITH THE STRONGER LIFT TO THE WEST WITH SOME
UPSLOPE COMPONENT RESULTING IN RAIN AND SNOW FOR PARTS OF THE
NEBRASKA PANHANDLE. THE LOWER CIGS HAVE SHIFTED TOWARD VALENTINE
WHERE THEY HAVE 34 DEGREES AND LIGHT SNOW. SOME SPRINKLES OR
FLURRIES WITH SPRINKLES MAY TRY TO DEVELOP THIS AFTERNOON FOR
AREAS NEAR ALBION...VERDIGRE... AND NORFOLK. ADJUSTED TEMPERATURES
DOWN IN THE NORTH DUE TO THE CLOUDCOVER...BUT STILL IN THE 30S TO
LOWER 40S. THE SOUTH WILL SEE MORE BREAKS NEAR THE KANSAS
BORDER...SO HAVE HIGHS IN THE LOWER 50S. THE NEXT WAVE WILL MOVE
INTO SOUTH DAKOTA TONIGHT AND THIS SHOULD FURTHER SATURATED THE
COLUMN WITH EVEN COLDER DENDRITIC TEMPS ALOFT TO WORK WITH...SO
LIGHT SNOW AND FLURRIES SHOULD HAVE A BETTER CHANCE OF REACHING
THE GROUND.
&&
.PREV DISCUSSION... /ISSUED 1225 PM CST SUN NOV 25 2012/
AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
VFR CIGS EXPECTED THRU 00Z WITH CIGS FL060-120.
A COUPLE OF SHORTWAVES WILL AFFECT THE AREA DURING THE PERIOD
WITH DETERIORATING CONDITIONS. THE WSR-88D IS SHOWING A BAND OF
PRECIPITATION FROM MONTANA TO NORTHERN NEBRASKA. THE CIGS ARE
LOWERING TO UNDER FL040 AT AINSWORTH AND ARE MVFR/IFR WITH THE
PRECIPITATION REACHING THE GROUND WITH RAIN AND SNOW IN NORTHWEST
NEBRASKA. THE ECHOES MOVING INTO NORTHEAST NEBRASKA ARE CLOUDS OR
VIRGA. WE COULD SEE SOME SPRINKLES OR SPRINKLES MIXED WITH
FLURRIES AT KOFK LATER THIS AFTERNOON AND THIS EVENING. MVFR CIGS
AND -SN POSSIBLE AT KOFK LATER TONIGHT AND MONDAY MORNING. SOME
QUESTION AS TO WHERE FLURRIES/LIGHT SNOW BAND WILL SET UP IF KOMA
OR KLNK WILL BE IN THE BAND...SO FOR NOW TRENDED DOWNWARD WITH CIG
HEIGHTS AFTER 06Z. SURFACE WINDS WILL GENERALLY BE FROM THE NORTH
AT 5 TO 10KTS.
ZAPOTOCNY
PREV DISCUSSION... /ISSUED 331 AM CST SUN NOV 25 2012/
DISCUSSION...
THE MAIN FORECAST CONCERN CONTINUES TO CENTER THE THE SHORTWAVE
CURRENTLY LOCATED OVER THE STATE OF WA EARLY THIS MORNING PER IR
SAT IMAGERY. THIS SHORTWAVE TROUGH AND ASSOCIATED FORCING FOR
ASCENT WILL TRACK EAST TODAY...AND ACROSS THE REGION LATE TONIGHT
AND INTO MONDAY MORNING. AHEAD OF THE WAVE...ALONG THE PRE-
EXISTING MID LEVEL THERMAL GRADIENT...WEAK CONFLUENT FLOW WILL
CONTINUE TODAY LEADING TO A GOOD DEAL OF MID AND HIGH LEVEL CLOUDS
FOR THE CNTRL AND NORTHERN FORECAST AREA. THE RAP APPEARS TO HAVE
THE BEST HANDLE ON THE STRATUS DECK OVER THE EASTERN DAKOTAS/MN
THIS MORNING AND THE MODEL INDICATES THE CLOUDS WILL MOVE INTO
NORTHEAST NEB AND WEST CNTRL IA...WHICH SEEMS REASONABLE BUT THIS
IS LIKELY THE FARTHEST SOUTH THE LOW CLOUDS WILL GET TODAY. THE
DEGREE OF LOW LEVEL DRY AIR OVER THE NRN CWA NEAR THE THERMAL
GRADIENT CONTS TO MAKE THE CHANCE OF ANY PRECIP MAKING IT TO THE
SURFACE UNLIKELY TODAY AND WE WILL MAINTAIN THE DRY FORECAST.
A LITTLE BETTER FRONTAL CIRCULATION WILL START TO DEVELOP TONIGHT
AS THE QG FORCING ASSOCIATED WITH THE INCOMING SHORTWAVE STARTS
SPREADING INTO THE AREA. THE ATMOSPHERE ABOVE THE FRONTAL ZONE IS
VERY STABLE THOUGH WITH EPV VALUES ABOVE 1 PVU AND THUS OVERALL
VERTICAL MOTION DUE TO THE 700-750 MB FRONTOGENESIS APPEARS LIKE
IT WILL BE FAIRLY WEAK. NEVERTHELESS WITH THE LONG DURATION OF
PERSISTENT WEAK LIFT THE ATMOSPHERE WILL TRY TO SATURATION FROM
THE TOP DOWN WITH SOME LIGHT SNOW REACHING THE SURFACE IN A FAIRLY
NARROW BAND FROM AROUND BVN/OLU/LNK BY MON MORNING. WE HAVE
CONTINUED TO MENTION SOME HALF INCH SNOW TOTALS IN THIS SMALL
AREA WHERE WE HAVE ALSO INCREASED POPS. WE HAVE LOWERED OR REMOVED
POPS MOST OTHER PLACES WITH JUST SOME FLURRIES POSSIBLE LATE
TONIGHT INTO MON. THE LIGHT SNOW WILL LIKELY LINGER INTO MONDAY
MORNING IN THE PREVIOUSLY MENTIONED BAND BEFORE THE UPPER LEVEL
SHORTWAVE TROUGH QUICKLY EXITS TO THE EAST AND LARGE-SCALE
SUBSIDENCE DEVELOPS BY MON AFTERNOON. THIS SHOULD ACT TO START TO
CLEAR THE CLOUDS BY LATE AFTERNOON FOR A GOOD PART OF THE AREA AS
WEAK SURFACE HIGH PRESSURE BUILDS IN.
NORTHWEST FLOW WILL CONTINUE FOR THE REST OF THE FORECAST PERIOD
BECOMING INCREASINGLY WESTERLY BY LATE IN THE PERIOD. THIS IS A
FAIRLY UNSTABLE UPPER LEVEL PATTERN AND SO CONFIDENCE IN THE
SENSIBLE WEATHER LATE IN THE PERIOD IS PRETTY LOW. THE GFS HAS A
STRONGER SYSTEM MOVING THROUGH THE AREA ON THU BUT THE MODEL
APPEARS TO BE AN OUTLIER WHEN COMPARED TO OTHER GLOBAL GUIDANCE
AND WE WILL DISREGARD FOR NOW. TEMPERATURES WILL SLOWLY WARM
THROUGH THE PERIOD WITH HIGHS/LOWS WELL ABOVE NORMAL BY NEXT
WEEKEND.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1225 PM CST SUN NOV 25 2012
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
VFR CIGS EXPECTED THRU 00Z WITH CIGS FL060-120.
A COUPLE OF SHORTWAVES WILL AFFECT THE AREA DURING THE PERIOD
WITH DETERIORATING CONDITIONS. THE WSR-88D IS SHOWING A BAND OF
PRECIPITATION FROM MONTANA TO NORTHERN NEBRASKA. THE CIGS ARE
LOWERING TO UNDER FL040 AT AINSWORTH AND ARE MVFR/IFR WITH THE
PRECIPITATION REACHING THE GROUND WITH RAIN AND SNOW IN NORTHWEST
NEBRASKA. THE ECHOES MOVING INTO NORTHEAST NEBRASKA ARE CLOUDS OR
VIRGA. WE COULD SEE SOME SPRINKLES OR SPRINKLES MIXED WITH
FLURRIES AT KOFK LATER THIS AFTERNOON AND THIS EVENING. MVFR CIGS
AND -SN POSSIBLE AT KOFK LATER TONIGHT AND MONDAY MORNING. SOME
QUESTION AS TO WHERE FLURRIES/LIGHT SNOW BAND WILL SET UP IF KOMA
OR KLNK WILL BE IN THE BAND...SO FOR NOW TRENDED DOWNWARD WITH CIG
HEIGHTS AFTER 06Z. SURFACE WINDS WILL GENERALLY BE FROM THE NORTH
AT 5 TO 10KTS.
ZAPOTOCNY
&&
.PREV DISCUSSION... /ISSUED 331 AM CST SUN NOV 25 2012/
DISCUSSION...
THE MAIN FORECAST CONCERN CONTINUES TO CENTER THE THE SHORTWAVE
CURRENTLY LOCATED OVER THE STATE OF WA EARLY THIS MORNING PER IR
SAT IMAGERY. THIS SHORTWAVE TROUGH AND ASSOCIATED FORCING FOR
ASCENT WILL TRACK EAST TODAY...AND ACROSS THE REGION LATE TONIGHT
AND INTO MONDAY MORNING. AHEAD OF THE WAVE...ALONG THE PRE-
EXISTING MID LEVEL THERMAL GRADIENT...WEAK CONFLUENT FLOW WILL
CONTINUE TODAY LEADING TO A GOOD DEAL OF MID AND HIGH LEVEL CLOUDS
FOR THE CNTRL AND NORTHERN FORECAST AREA. THE RAP APPEARS TO HAVE
THE BEST HANDLE ON THE STRATUS DECK OVER THE EASTERN DAKOTAS/MN
THIS MORNING AND THE MODEL INDICATES THE CLOUDS WILL MOVE INTO
NORTHEAST NEB AND WEST CNTRL IA...WHICH SEEMS REASONABLE BUT THIS
IS LIKELY THE FARTHEST SOUTH THE LOW CLOUDS WILL GET TODAY. THE
DEGREE OF LOW LEVEL DRY AIR OVER THE NRN CWA NEAR THE THERMAL
GRADIENT CONTS TO MAKE THE CHANCE OF ANY PRECIP MAKING IT TO THE
SURFACE UNLIKELY TODAY AND WE WILL MAINTAIN THE DRY FORECAST.
A LITTLE BETTER FRONTAL CIRCULATION WILL START TO DEVELOP TONIGHT
AS THE QG FORCING ASSOCIATED WITH THE INCOMING SHORTWAVE STARTS
SPREADING INTO THE AREA. THE ATMOSPHERE ABOVE THE FRONTAL ZONE IS
VERY STABLE THOUGH WITH EPV VALUES ABOVE 1 PVU AND THUS OVERALL
VERTICAL MOTION DUE TO THE 700-750 MB FRONTOGENESIS APPEARS LIKE
IT WILL BE FAIRLY WEAK. NEVERTHELESS WITH THE LONG DURATION OF
PERSISTENT WEAK LIFT THE ATMOSPHERE WILL TRY TO SATURATION FROM
THE TOP DOWN WITH SOME LIGHT SNOW REACHING THE SURFACE IN A FAIRLY
NARROW BAND FROM AROUND BVN/OLU/LNK BY MON MORNING. WE HAVE
CONTINUED TO MENTION SOME HALF INCH SNOW TOTALS IN THIS SMALL
AREA WHERE WE HAVE ALSO INCREASED POPS. WE HAVE LOWERED OR REMOVED
POPS MOST OTHER PLACES WITH JUST SOME FLURRIES POSSIBLE LATE
TONIGHT INTO MON. THE LIGHT SNOW WILL LIKELY LINGER INTO MONDAY
MORNING IN THE PREVIOUSLY MENTIONED BAND BEFORE THE UPPER LEVEL
SHORTWAVE TROUGH QUICKLY EXITS TO THE EAST AND LARGE-SCALE
SUBSIDENCE DEVELOPS BY MON AFTERNOON. THIS SHOULD ACT TO START TO
CLEAR THE CLOUDS BY LATE AFTERNOON FOR A GOOD PART OF THE AREA AS
WEAK SURFACE HIGH PRESSURE BUILDS IN.
NORTHWEST FLOW WILL CONTINUE FOR THE REST OF THE FORECAST PERIOD
BECOMING INCREASINGLY WESTERLY BY LATE IN THE PERIOD. THIS IS A
FAIRLY UNSTABLE UPPER LEVEL PATTERN AND SO CONFIDENCE IN THE
SENSIBLE WEATHER LATE IN THE PERIOD IS PRETTY LOW. THE GFS HAS A
STRONGER SYSTEM MOVING THROUGH THE AREA ON THU BUT THE MODEL
APPEARS TO BE AN OUTLIER WHEN COMPARED TO OTHER GLOBAL GUIDANCE
AND WE WILL DISREGARD FOR NOW. TEMPERATURES WILL SLOWLY WARM
THROUGH THE PERIOD WITH HIGHS/LOWS WELL ABOVE NORMAL BY NEXT
WEEKEND.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
524 AM CST SUN NOV 25 2012
.AVIATION...
12Z TAFS FOR KOMA...KLNK...AND KOFK.
DETERIORATING CONDITIONS ARE EXPECTED THROUGH THE TAF CYCLE. MID-
LEVEL CLOUDS ARE EXPECTED TODAY...WITH CIGS LOWERING LATER TODAY
AND ESPECIALLY THIS EVENING. HAVE INCLUDED A PROGRESSION THROUGH
MVFR TO IFR...WITH EARLIER DETERIORATION AT KOFK AND LATEST AT
KLNK. HAVE NOT INCLUDED -SN AT ANY SITES AS CONFIDENCE IS LOW ON
COVERAGE...BUT KOFK WOULD HAVE THE BEST SHOT...LIKELY FROM AROUND
08-12Z. ALSO HAVE NOT INCLUDED CIGS LOWER THAN 1KFT...THOUGH SOME
GUIDANCE SUGGESTS LOWER CIGS ARE POSSIBLE AFTER 06Z. WINDS WILL
GRAUDALLY VEER FROM NORTH-NORTHWEST TO NORTHEASTERLY TODAY...WITH
SPEEDS MAINLY AROUND 10KT.
MAYES
&&
.PREV DISCUSSION... /ISSUED 331 AM CST SUN NOV 25 2012/
DISCUSSION...
THE MAIN FORECAST CONCERN CONTINUES TO CENTER THE THE SHORTWAVE
CURRENTLY LOCATED OVER THE STATE OF WA EARLY THIS MORNING PER IR
SAT IMAGERY. THIS SHORTWAVE TROUGH AND ASSOCIATED FORCING FOR
ASCENT WILL TRACK EAST TODAY...AND ACROSS THE REGION LATE TONIGHT
AND INTO MONDAY MORNING. AHEAD OF THE WAVE...ALONG THE PRE-
EXISTING MID LEVEL THERMAL GRADIENT...WEAK CONFLUENT FLOW WILL
CONTINUE TODAY LEADING TO A GOOD DEAL OF MID AND HIGH LEVEL CLOUDS
FOR THE CNTRL AND NORTHERN FORECAST AREA. THE RAP APPEARS TO HAVE
THE BEST HANDLE ON THE STRATUS DECK OVER THE EASTERN DAKOTAS/MN
THIS MORNING AND THE MODEL INDICATES THE CLOUDS WILL MOVE INTO
NORTHEAST NEB AND WEST CNTRL IA...WHICH SEEMS REASONABLE BUT THIS
IS LIKELY THE FARTHEST SOUTH THE LOW CLOUDS WILL GET TODAY. THE
DEGREE OF LOW LEVEL DRY AIR OVER THE NRN CWA NEAR THE THERMAL
GRADIENT CONTS TO MAKE THE CHANCE OF ANY PRECIP MAKING IT TO THE
SURFACE UNLIKELY TODAY AND WE WILL MAINTAIN THE DRY FORECAST.
A LITTLE BETTER FRONTAL CIRCULATION WILL START TO DEVELOP TONIGHT
AS THE QG FORCING ASSOCIATED WITH THE INCOMING SHORTWAVE STARTS
SPREADING INTO THE AREA. THE ATMOSPHERE ABOVE THE FRONTAL ZONE IS
VERY STABLE THOUGH WITH EPV VALUES ABOVE 1 PVU AND THUS OVERALL
VERTICAL MOTION DUE TO THE 700-750 MB FRONTOGENESIS APPEARS LIKE
IT WILL BE FAIRLY WEAK. NEVERTHELESS WITH THE LONG DURATION OF
PERSISTENT WEAK LIFT THE ATMOSPHERE WILL TRY TO SATURATION FROM
THE TOP DOWN WITH SOME LIGHT SNOW REACHING THE SURFACE IN A FAIRLY
NARROW BAND FROM AROUND BVN/OLU/LNK BY MON MORNING. WE HAVE
CONTINUED TO MENTION SOME HALF INCH SNOW TOTALS IN THIS SMALL
AREA WHERE WE HAVE ALSO INCREASED POPS. WE HAVE LOWERED OR REMOVED
POPS MOST OTHER PLACES WITH JUST SOME FLURRIES POSSIBLE LATE
TONIGHT INTO MON. THE LIGHT SNOW WILL LIKELY LINGER INTO MONDAY
MORNING IN THE PREVIOUSLY MENTIONED BAND BEFORE THE UPPER LEVEL
SHORTWAVE TROUGH QUICKLY EXITS TO THE EAST AND LARGE-SCALE
SUBSIDENCE DEVELOPS BY MON AFTERNOON. THIS SHOULD ACT TO START TO
CLEAR THE CLOUDS BY LATE AFTERNOON FOR A GOOD PART OF THE AREA AS
WEAK SURFACE HIGH PRESSURE BUILDS IN.
NORTHWEST FLOW WILL CONTINUE FOR THE REST OF THE FORECAST PERIOD
BECOMING INCREASINGLY WESTERLY BY LATE IN THE PERIOD. THIS IS A
FAIRLY UNSTABLE UPPER LEVEL PATTERN AND SO CONFIDENCE IN THE
SENSIBLE WEATHER LATE IN THE PERIOD IS PRETTY LOW. THE GFS HAS A
STRONGER SYSTEM MOVING THROUGH THE AREA ON THU BUT THE MODEL
APPEARS TO BE AN OUTLIER WHEN COMPARED TO OTHER GLOBAL GUIDANCE
AND WE WILL DISREGARD FOR NOW. TEMPERATURES WILL SLOWLY WARM
THROUGH THE PERIOD WITH HIGHS/LOWS WELL ABOVE NORMAL BY NEXT
WEEKEND.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
331 AM CST SUN NOV 25 2012
.DISCUSSION...
THE MAIN FORECAST CONCERN CONTINUES TO CENTER THE THE SHORTWAVE
CURRENTLY LOCATED OVER THE STATE OF WA EARLY THIS MORNING PER IR
SAT IMAGERY. THIS SHORTWAVE TROUGH AND ASSOCIATED FORCING FOR
ASCENT WILL TRACK EAST TODAY...AND ACROSS THE REGION LATE TONIGHT
AND INTO MONDAY MORNING. AHEAD OF THE WAVE...ALONG THE PRE-
EXISTING MID LEVEL THERMAL GRADIENT...WEAK CONFLUENT FLOW WILL
CONTINUE TODAY LEADING TO A GOOD DEAL OF MID AND HIGH LEVEL CLOUDS
FOR THE CNTRL AND NORTHERN FORECAST AREA. THE RAP APPEARS TO HAVE
THE BEST HANDLE ON THE STRATUS DECK OVER THE EASTERN DAKOTAS/MN
THIS MORNING AND THE MODEL INDICATES THE CLOUDS WILL MOVE INTO
NORTHEAST NEB AND WEST CNTRL IA...WHICH SEEMS REASONABLE BUT THIS
IS LIKELY THE FARTHEST SOUTH THE LOW CLOUDS WILL GET TODAY. THE
DEGREE OF LOW LEVEL DRY AIR OVER THE NRN CWA NEAR THE THERMAL
GRADIENT CONTS TO MAKE THE CHANCE OF ANY PRECIP MAKING IT TO THE
SURFACE UNLIKELY TODAY AND WE WILL MAINTAIN THE DRY FORECAST.
A LITTLE BETTER FRONTAL CIRCULATION WILL START TO DEVELOP TONIGHT
AS THE QG FORCING ASSOCIATED WITH THE INCOMING SHORTWAVE STARTS
SPREADING INTO THE AREA. THE ATMOSPHERE ABOVE THE FRONTAL ZONE IS
VERY STABLE THOUGH WITH EPV VALUES ABOVE 1 PVU AND THUS OVERALL
VERTICAL MOTION DUE TO THE 700-750 MB FRONTOGENESIS APPEARS LIKE
IT WILL BE FAIRLY WEAK. NEVERTHELESS WITH THE LONG DURATION OF
PERSISTENT WEAK LIFT THE ATMOSPHERE WILL TRY TO SATURATION FROM
THE TOP DOWN WITH SOME LIGHT SNOW REACHING THE SURFACE IN A FAIRLY
NARROW BAND FROM AROUND BVN/OLU/LNK BY MON MORNING. WE HAVE
CONTINUED TO MENTION SOME HALF INCH SNOW TOTALS IN THIS SMALL
AREA WHERE WE HAVE ALSO INCREASED POPS. WE HAVE LOWERED OR REMOVED
POPS MOST OTHER PLACES WITH JUST SOME FLURRIES POSSIBLE LATE
TONIGHT INTO MON. THE LIGHT SNOW WILL LIKELY LINGER INTO MONDAY
MORNING IN THE PREVIOUSLY MENTIONED BAND BEFORE THE UPPER LEVEL
SHORTWAVE TROUGH QUICKLY EXITS TO THE EAST AND LARGE-SCALE
SUBSIDENCE DEVELOPS BY MON AFTERNOON. THIS SHOULD ACT TO START TO
CLEAR THE CLOUDS BY LATE AFTERNOON FOR A GOOD PART OF THE AREA AS
WEAK SURFACE HIGH PRESSURE BUILDS IN.
NORTHWEST FLOW WILL CONTINUE FOR THE REST OF THE FORECAST PERIOD
BECOMING INCREASINGLY WESTERLY BY LATE IN THE PERIOD. THIS IS A
FAIRLY UNSTABLE UPPER LEVEL PATTERN AND SO CONFIDENCE IN THE
SENSIBLE WEATHER LATE IN THE PERIOD IS PRETTY LOW. THE GFS HAS A
STRONGER SYSTEM MOVING THROUGH THE AREA ON THU BUT THE MODEL
APPEARS TO BE AN OUTLIER WHEN COMPARED TO OTHER GLOBAL GUIDANCE
AND WE WILL DISREGARD FOR NOW. TEMPERATURES WILL SLOWLY WARM
THROUGH THE PERIOD WITH HIGHS/LOWS WELL ABOVE NORMAL BY NEXT
WEEKEND.
BOUSTEAD
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
WEAK WIND SHIFT WAS PRESSING TOWARD LNK AND OMA LATE SATURDAY
EVENING. A SOMEWHAT STRONGER BOUNDARY OVER NRN SD WILL MOVE INTO
NRN NEBRASKA LATE TONIGHT BEFORE WEAKENING DURING THE DAY AS IT
CONTINUES SOUTHWARD. LOW CLOUDS BEHIND THIS FRONT WILL NEED
MONITORING AS IT APPEARS THEY COULD APPROACH KOFK AND POSSIBLY
EVEN OMAHA BEFORE ERODING OR REORGANIZING TO THE WEST. OTHERWISE A
DISTURBANCE MOVING SE TOWARD CENTRAL NEBRASKA SHOULD BRING LOWER
CIGS TO OMA/OFK SUNDAY EVENING AND SNOW CHANCES TO THE AREA SUN
NIGHT/MONDAY MORNING. WITH LOW LEVEL DRY AIR EXPECTED TO BE IN
PLACE SUN AFTN...NO SNOW MENTION OR MVFR CIGS WERE FORECAST BEFORE
25/06Z.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
452 PM EST SUN NOV 25 2012
.SYNOPSIS...
LAKE EFFECT SNOWS WILL IMPACT THE TUG HILL PLATEAU REGION
TONIGHT...AND THEN DROP BACK SOUTH TO COVER MORE OF CENTRAL NEW
YORK WITH SNOW SHOWERS FOR THE FIRST HALF OF MONDAY. SNOW SHOWERS
DIMINISH FOR A TIME MONDAY AFTERNOON...BEFORE A FAST MOVING LOW PRESSURE
SYSTEM BRINGS A PERIOD OF LIGHT SNOW AND FLURRIES TO NORTHERN
PENNSYLVANIA AND SOUTHERN NEW YORK LATE MONDAY NIGHT AND EARLY
TUESDAY. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
445 PM UPDATE...
HAVE RECEIVED A FEW REPORTS OF OVER SIX INCHES OF SNOW ACROSS
NORTHERN PORTIONS OF ONEIDA COUNTY. LATEST RADAR TRENDS SHOW A
WELL DEVELOPED LAKE BAND EXTENDING INLAND FROM LAKE ONTARIO...WITH
LITTLE INDICATION SNOWS WILL STOP ANYTIME SOON. BAND WILL LIKELY
LIFT NORTH OF THE AREA FOR A TIME LATER THIS EVENING BEFORE
SHIFTING SOUTH ACROSS NORTHERN ONEIDA COUNTY ONCE AGAIN AS WINDS
AGAIN BECOME WESTERLY AFTER MIDNIGHT. THAT SAID...HAVE DECIDED TO
UPGRADE THE ADVISORY TO A WARNING AS ADDITIONAL ROUNDS OF SNOW
COMBINED WITH SNOW THAT IS OCCURRING NOW WILL LIKELY PUSH
ACCUMULATIONS ABOVE WARNING CRITERIA. NEW WSW ALREADY POSTED. WILL
CONTINUE TO MONITOR.
PREVIOUS NEAR TERM DISCUSSION...
MADE SEVERAL CHANGES TO THE FCST FOR TODAY THROUGH TONIGHT.
NAMELY HAD TO ADJUST POPS HIGHER AS UPPER WAVE CAME IN FROM THE
WEST FOR A HIGH OCCURRENCE/LOW QPF EVENT WITH GENERALLY LIGHT
SNOW/FLURRIES ACROSS THE REGION. WITHIN THE GENERAL LIGHT SNOW
AREA REMAINS THE EMBEDDED LAKE BANDS...AND THE ONEIDA CENTRIC BAND
WAS BECOMING RE- ESTABLISHED ON A 280 FLOW PATTERN THIS AFTERNOON.
SOME REPORTS OF 2-3 INCHES HAVE BEEN RECEIVED FROM ROME NORTHWARD
SINCE THIS MORNING. BAND SHOULD BE ABLE TO PRODUCE ANOTHER FEW
INCHES THIS AFTERNOON AND EARLY EVENING BEFORE PULLING JUST NORTH
OF THE COUNTY LATER IN THE EVENING. FOLLOWED OUR LOCAL WRF MODEL
IN REGARDS TO TIMING AND PLACEMENT OF LIFT/MOISTURE AND QPF
FIELDS...ALTHOUGH NAM12 AND RAP MODEL BUFKIT FIELDS ARE
COMPARABLE. THE BAND THEN LOOKS TO COME BACK IN JUST PRIOR TO
DAYBREAK MONDAY WITH ANOTHER FEW INCHES POSSIBLE. SHEAR ALONG WITH
WEAKENING FLOW AND DIURNAL DISRUPTION OF THE LAKE INSTABILITY
PROCESSES ALLOW FOR WEAKENING MONDAY AFTERNOON WITH NOMINAL
ACCUMS.
SEE LITTLE VARIATION IN TEMPERATURES WITH LOWS IN THE UPR 20S
TONIGHT AND HIGHS MONDAY GENERALLY MID 30S.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
NEXT ITEM TO FOCUS ON WILL BE APPROACHING OPEN WAVE AND WEAK LOW
PRESSURE ON MONDAY NIGHT AND EARLY TUESDAY. THIS LOOKS TO BE A
RATHER MINIMAL EVENT WITH SNOW BREAKING OUT OVER THE LOWER OH/TN
VALLEY REGION DUE TO ISENTROPIC LIFT AHEAD OF THE UPPER WAVE WHICH
THEN LIFTS NORTH INTO MAINLY THE SOUTHERN HALF OF NY AND NEPA.
GFS/NAM IN REASONABLE AGREEMENT THAT WE NEED TO SPEED UP TIMING BY
A GOOD 6 HOURS AS WAA PRECIP DOES TEND TO DEVELOP QUICKER AND
THESE TRENDS SUPPORT THAT. WILL BRING IN LIGHT SNOW BETWEEN 06Z-12Z
TUESDAY...WITH A QUICK HITTING EVENT THAT APPEARS TO BE OUT OF THE
PICTURE BY EARLY AFTERNOON. THIS...ALONG WITH MARGINAL TEMPERATURES
AND MINIMAL LIFT SHOULD BE A LIGHT EVENT WITH NOMINAL ACCUMULATIONS
RANGING FROM A DUSTING TO AN INCH...POSSIBLY 2 INCHES IN THE
MOUNTAINS OF NEPA. THE NORTHERN EXTENT LOOKS TO BE AROUND THE
SOUTHERN TIER OF NY...WITH POSSIBLY A FEW FLURRIES UP NORTH.
HIGH PRESSURE THEN BUILDS IN FROM THE SOUTHWEST...BUT BROAD
CYCLONIC FLOW ALOFT AND INCREASING LOW LEVEL MOISTURE ON NWLY LOWER
ATMOSPHERE FLOW SHOULD SPELL A BROAD AREA OF FLURRIES DEVELOPING
BY WEDNESDAY AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
GFS/ECMWF IN GOOD AGREEMENT THROUGH THURSDAY... THEN SOME
DIFFERENCES DEVELOP WITH THE NEXT SYSTEM APPROACHING THE AREA FROM
THE MIDWEST. WEDNESDAY NIGHT THROUGH THURSDAY WILL BE COLD WITH
SCATTERED SNOW SHOWERS NEAR LAKE ONTARIO... OTHERWISE DRY. THE GFS
BRINGS PRECIPITATION ASSOCIATED WITH THE NEXT SYSTEM FRIDAY NIGHT
AND SATURDAY... WHILE THE ECMWF IS MUCH SLOWER AND MORE AMPLIFIED
WITH THIS SYSTEM... NOT BRINGING ANY PRECIPITATION INTO THE AREA
UNTIL AROUND SUNDAY. AT THIS POINT HAVE GONE WITH THE HPC SCENARIO
WHICH FAVORS THE SLOWER ECMWF. BASED ON THIS HAVE KEPT
PRECIPITATION OUT OF THE FORECAST THROUGH SATURDAY. TEMPERATURES
THURSDAY THROUGH SATURDAY WILL BE NEAR TO SLIGHTLY BELOW NORMAL...
WITH HIGHS MAINLY IN THE 30S AND LOWS IN THE 20S.
&&
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
A BAND OF LAKE EFFECT SNOW WILL BRING IFR VSBYS AND CIGS TO RME
THROUGH THIS AFTERNOON. THE BAND WILL LIFT NORTH OF RME TONIGHT
THEN WILL COME BACK SOUTH ACROSS THE RME AREA MONDAY MORNING WITH
ANOTHER PERIOD OF IFR VSBYS AND CIGS. THE BAND WILL REMAIN NORTH
OF SYR THROUGH TONIGHT... THEN A PERIOD OF IFR CIGS AND VSBYS WILL
BE POSSIBLE MONDAY MORNING AS THE BAND MOVES BACK TO THE SOUTH.
OTHERWISE... PERIODS OF LIGHT SNOW WILL AFFECT ITH/ELM/BGM THROUGH
THIS AFTERNOON WITH OCCASIONAL IFR VSBYS. THIS LIGHT SNOW WILL END
TOWARD EVENING WITH VFR VSBYS TONIGHT THROUGH MONDAY ALONG WITH
VFR TO OCCASIONAL MVFR CIGS.
MAINLY VFR CONDITIONS CAN BE EXPECTED AT AVP THROUGH MONDAY.
WINDS WILL BE MAINLY FROM THE WEST AT 5 TO 15 KTS TODAY... LESS
THAN 10 KTS TONIGHT AND 5 TO 15 KTS ON MONDAY.
OUTLOOK...
TUE...VFR-MVFR WITH CHC IFR AS STORM SYSTEM SLIDES JUST TO THE
SOUTH...ESPECIALLY AVP AND BGM.
WED...VFR-MVFR WITH CHC IFR IN LAKE SNOW SHOWERS...MAINLY CNTRL NY.
THU...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW WARNING UNTIL 1 PM EST TUESDAY FOR NYZ009.
&&
$$
SYNOPSIS...JAB
NEAR TERM...CMG/JAB
SHORT TERM...JAB
LONG TERM...MSE
AVIATION...MSE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
245 PM EST SUN NOV 25 2012
.SYNOPSIS...
LAKE EFFECT SNOWS WILL IMPACT THE TUG HILL PLATEAU REGION
TONIGHT...AND THEN DROP BACK SOUTH TO COVER MORE OF CENTRAL NEW
YORK WITH SNOW SHOWERS FOR THE FIRST HALF OF MONDAY. SNOW SHOWERS
DIMINISH FOR A TIME MONDAY AFTERNOON...BEFORE A FAST MOVING LOW PRESSURE
SYSTEM BRINGS A PERIOD OF LIGHT SNOW AND FLURRIES TO NORTHERN
PENNSYLVANIA AND SOUTHERN NEW YORK LATE MONDAY NIGHT AND EARLY
TUESDAY. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
MADE SEVERAL CHANGES TO THE FCST FOR TODAY THROUGH TONIGHT. NAMELY
HAD TO ADJUST POPS HIGHER AS UPPER WAVE CAME IN FROM THE WEST FOR
A HIGH OCCURRANCE/LOW QPF EVENT WITH GENERALLY LIGHT SNOW/FLURRIES
ACROSS THE REGION. WITHIN THE GENERAL LIGHT SNOW AREA REMAINS THE
EMBEDDED LAKE BANDS...AND THE ONEIDA CENTRIC BAND WAS BECOMING RE-
ESTABLISHED ON A 280 FLOW PATTERN THIS AFTERNOON. SOME REPORTS OF
2-3 INCHES HAVE BEEN RECEIVED FROM ROME NORTHWARD SINCE THIS
MORNING. BAND SHOULD BE ABLE TO PRODUCE ANOTHER FEW INCHES THIS
AFTERNOON AND EARLY EVENING BEFORE PULLING JUST NORTH OF THE
COUNTY LATER IN THE EVENING. FOLLOWED OUR LOCAL WRF MODEL IN REGARDS TO
TIMING AND PLACEMENT OF LIFT/MOISTURE AND QPF FIELDS...ALTHOUGH
NAM12 AND RAP MODEL BUFKIT FIELDS ARE COMPARABLE. THE BAND THEN
LOOKS TO COME BACK IN JUST PRIOR TO DAYBREAK MONDAY WITH ANOTHER
FEW INCHES POSSIBLE. SHEAR ALONG WITH WEAKENING FLOW AND DIURNAL
DISRUPTION OF THE LAKE INSTABILITY PROCESSES ALLOW FOR WEAKENING
MONDAY AFTERNOON WITH NOMINAL ACCUMS.
HAVE DECIDED TO STICK WITH THE LAKE SNOW ADVISORY SINCE THIS LOOKS
TO BE A FAIRLY DRAWN OUT EVENT...ALONG WITH AN ANTICIPATED BREAK
IN THE ACTION RIGHT IN THE MIDDLE OF THE EVENT TONIGHT...ALTHOUGH
SOME OVERALL SNOW TOTALS COULD BE CLOSE TO THE LOW WARNING CRITERIA.
SEE LITTLE VARIATION IN TEMPERATURES WITH LOWS IN THE UPR 20S
TONIGHT AND HIGHS MONDAY GENERALLY MID 30S.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
NEXT ITEM TO FOCUS ON WILL BE APPROACHING OPEN WAVE AND WEAK LOW
PRESSURE ON MONDAY NIGHT AND EARLY TUESDAY. THIS LOOKS TO BE A
RATHER MINIMAL EVENT WITH SNOW BREAKING OUT OVER THE LOWER OH/TN
VALLEY REGION DUE TO ISENTROPIC LIFT AHEAD OF THE UPPER WAVE WHICH
THEN LIFTS NORTH INTO MAINLY THE SOUTHERN HALF OF NY AND NEPA.
GFS/NAM IN REASONABLE AGREEMENT THAT WE NEED TO SPEED UP TIMING BY
A GOOD 6 HOURS AS WAA PRECIP DOES TEND TO DEVELOP QUICKER AND
THESE TRENDS SUPPORT THAT. WILL BRING IN LIGHT SNOW BETWEEN 06Z-12Z
TUESDAY...WITH A QUICK HITTING EVENT THAT APPEARS TO BE OUT OF THE
PICTURE BY EARLY AFTERNOON. THIS...ALONG WITH MARGINAL TEMPERATURES
AND MINIMAL LIFT SHOULD BE A LIGHT EVENT WITH NOMINAL ACCUMULATIONS
RANGING FROM A DUSTING TO AN INCH...POSSIBLY 2 INCHES IN THE
MOUNTAINS OF NEPA. THE NORTHERN EXTENT LOOKS TO BE AROUND THE
SOUTHERN TIER OF NY...WITH POSSIBLY A FEW FLURRIES UP NORTH.
HIGH PRESSURE THEN BUILDS IN FROM THE SOUTHWEST...BUT BROAD
CYCLONC FLOW ALOFT AND INCREASING LOW LEVEL MOISTURE ON NWLY LOWER
ATMOSPHERE FLOW SHOULD SPELL A BROAD AREA OF FLURRIES DEVELOPING
BY WEDNESDAY AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
GFS/ECMWF IN GOOD AGREEMENT THROUGH THURSDAY... THEN SOME
DIFFERENCES DEVELOP WITH THE NEXT SYSTEM APPRAOCHING THE AREA FROM
THE MIDWEST. WEDNESDAY NIGHT THROUGH THURSDAY WILL BE COLD WITH
SCATTERED SNOW SHOWERS NEAR LAKE ONTARIO... OTHERWISE DRY. THE GFS
BRINGS PRECIPITATION ASSOCIATED WITH THE NEXT SYSTEM FRIDAY NIGHT
AND SATURDAY... WHILE THE ECMWF IS MUCH SLOWER AND MORE AMPLIFIED
WITH THIS SYSTEM... NOT BRINGING ANY PRECIPITATION INTO THE AREA
UNTIL AROUND SUNDAY. AT THIS POINT HAVE GONE WITH THE HPC SCENARIO
WHICH FAVORS THE SLOWER ECMWF. BASED ON THIS HAVE KEPT
PRECIPITATIN OUT OF THE FORECAST THROUGH SATURDAY. TEMPERATURES
THURSDAY THROUGH SATURDAY WILL BE NEAR TO SLIGHTLY BELOW NORMAL...
WITH HIGHS MAINLY IN THE 30S AND LOWS IN THE 20S.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
A BAND OF LAKE EFFECT SNOW WILL BRING IFR VSBYS AND CIGS TO RME
THROUGH THIS AFTERNOON. THE BAND WILL LIFT NORTH OF RME TONIGHT
THEN WILL COME BACK SOUTH ACROSS THE RME AREA MONDAY MORNING WITH
ANOTHER PERIOD OF IFR VSBYS AND CIGS. THE BAND WILL REMAIN NORTH
OF SYR THROUGH TONIGHT... THEN A PERIOD OF IFR CIGS AND VSBYS WILL
BE POSSIBLE MONDAY MORNING AS THE BAND MOVES BACK TO THE SOUTH.
OTHERWISE... PERIODS OF LIGHT SNOW WILL AFFECT ITH/ELM/BGM THROUGH
THIS AFTERNOON WITH OCCASIONAL IFR VSBYS. THIS LIGHT SNOW WILL END
TOWARD EVENING WITH VFR VSBYS TONIGHT THROUGH MONDAY ALONG WITH
VFR TO OCCASIONAL MVFR CIGS.
MAINLY VFR CONDITIONS CAN BE EXPECTED AT AVP THROUGH MONDAY.
WINDS WILL BE MAINLY FROM THE WEST AT 5 TO 15 KTS TODAY... LESS
THAN 10 KTS TONIGHT AND 5 TO 15 KTS ON MONDAY.
OUTLOOK...
TUE...VFR-MVFR WITH CHC IFR AS STORM SYSTEM SLIDES JUST TO THE
SOUTH...ESPECIALLY AVP AND BGM.
WED...VFR-MVFR WITH CHC IFR IN LAKE SNOW SHOWERS...MAINLY CNTRL NY.
THU...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 6 PM EST MONDAY FOR NYZ009.
&&
$$
SYNOPSIS...JAB
NEAR TERM...JAB
SHORT TERM...JAB
LONG TERM...MSE
AVIATION...MSE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
224 PM EST SUN NOV 25 2012
.SYNOPSIS...
LAKE EFFECT SNOWS WILL IMPACT THE TUG HILL PLATEAU REGION
TONIGHT...AND THEN DROP BACK SOUTH TO COVER MORE OF CENTRAL NEW
YORK WITH SNOW SHOWERS FOR THE FIRST HALF OF MONDAY. SNOW SHOWERS
DIMINISH FOR A TIME MONDAY AFTERNOON...BEFORE A FAST MOVING LOW PRESSURE
SYSTEM BRINGS A PERIOD OF LIGHT SNOW AND FLURRIES TO NORTHERN
PENNSYLVANIA AND SOUTHERN NEW YORK LATE MONDAY NIGHT AND EARLY
TUESDAY. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
MADE SEVERAL CHANGES TO THE FCST FOR TODAY THROUGH TONIGHT. NAMELY
HAD TO ADJUST POPS HIGHER AS UPPER WAVE CAME IN FROM THE WEST FOR
A HIGH OCCURRANCE/LOW QPF EVENT WITH GENERALLY LIGHT SNOW/FLURRIES
ACROSS THE REGION. WITHIN THE GENERAL LIGHT SNOW AREA REMAINS THE
EMBEDDED LAKE BANDS...AND THE ONEIDA CENTRIC BAND WAS BECOMING RE-
ESTABLISHED ON A 280 FLOW PATTERN THIS AFTERNOON. SOME REPORTS OF
2-3 INCHES HAVE BEEN RECEIVED FROM ROME NORTHWARD SINCE THIS
MORNING. BAND SHOULD BE ABLE TO PRODUCE ANOTHER FEW INCHES THIS
AFTERNOON AND EARLY EVENING BEFORE PULLING JUST NORTH OF THE
COUNTY LATER IN THE EVENING. FOLLOWED OUR LOCAL WRF MODEL IN REGARDS TO
TIMING AND PLACEMENT OF LIFT/MOISTURE AND QPF FIELDS...ALTHOUGH
NAM12 AND RAP MODEL BUFKIT FIELDS ARE COMPARABLE. THE BAND THEN
LOOKS TO COME BACK IN JUST PRIOR TO DAYBREAK MONDAY WITH ANOTHER
FEW INCHES POSSIBLE. SHEAR ALONG WITH WEAKENING FLOW AND DIURNAL
DISRUPTION OF THE LAKE INSTABILITY PROCESSES ALLOW FOR WEAKENING
MONDAY AFTERNOON WITH NOMINAL ACCUMS.
HAVE DECIDED TO STICK WITH THE LAKE SNOW ADVISORY SINCE THIS LOOKS
TO BE A FAIRLY DRAWN OUT EVENT...ALONG WITH AN ANTICIPATED BREAK
IN THE ACTION RIGHT IN THE MIDDLE OF THE EVENT TONIGHT...ALTHOUGH
SOME OVERALL SNOW TOTALS COULD BE CLOSE TO THE LOW WARNING CRITERIA.
SEE LITTLE VARIATION IN TEMPERATURES WITH LOWS IN THE UPR 20S
TONIGHT AND HIGHS MONDAY GENERALLY MID 30S.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
NEXT ITEM TO FOCUS ON WILL BE APPROACHING OPEN WAVE AND WEAK LOW
PRESSURE ON MONDAY NIGHT AND EARLY TUESDAY. THIS LOOKS TO BE A
RATHER MINIMAL EVENT WITH SNOW BREAKING OUT OVER THE LOWER OH/TN
VALLEY REGION DUE TO ISENTROPIC LIFT AHEAD OF THE UPPER WAVE WHICH
THEN LIFTS NORTH INTO MAINLY THE SOUTHERN HALF OF NY AND NEPA.
GFS/NAM IN REASONABLE AGREEMENT THAT WE NEED TO SPEED UP TIMING BY
A GOOD 6 HOURS AS WAA PRECIP DOES TEND TO DEVELOP QUICKER AND
THESE TRENDS SUPPORT THAT. WILL BRING IN LIGHT SNOW BETWEEN 06Z-12Z
TUESDAY...WITH A QUICK HITTING EVENT THAT APPEARS TO BE OUT OF THE
PICTURE BY EARLY AFTERNOON. THIS...ALONG WITH MARGINAL TEMPERATURES
AND MINIMAL LIFT SHOULD BE A LIGHT EVENT WITH NOMINAL ACCUMULATIONS
RANGING FROM A DUSTING TO AN INCH...POSSIBLY 2 INCHES IN THE
MOUNTAINS OF NEPA. THE NORTHERN EXTENT LOOKS TO BE AROUND THE
SOUTHERN TIER OF NY...WITH POSSIBLY A FEW FLURRIES UP NORTH.
HIGH PRESSURE THEN BUILDS IN FROM THE SOUTHWEST...BUT BROAD
CYCLONC FLOW ALOFT AND INCREASING LOW LEVEL MOISTURE ON NWLY LOWER
ATMOSPHERE FLOW SHOULD SPELL A BROAD AREA OF FLURRIES DEVELOPING
BY WEDNESDAY AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
THIS PERIOD LOOKS TO BE INITIALLY UNSETTLED AND COLDER THAN
NORMAL WITH A TREND TOWARD GENERALLY FAIR WEATHER AND NEAR NORMAL
TEMPERATURES AGAIN BY LATE IN THE WEEKEND. UNCERTAINTY REMAINS IN
THE DEVELOPMENT OF LOW PRESSURE ALONG THE EAST COAST FOR
TUESDAY...BUT SHOULD THAT OCCUR...ANY LINGERING PRECIPITATION
WOULD BE EXITING THE AREA TUESDAY NIGHT FOLLOWED BY COLDER AIR AND
DESTABILIZING CONDITIONS ACROSS LAKE ONTARIO. THIS WOULD REFOCUS SNOW
SHOWERS ACROSS CENTRAL NY FOR WEDNESDAY AND THURSDAY WITH CLOUDS
AND SOME FLURRIES FOR NEPA. HIGH PRESSURE AND BROAD RIDGING IS THEN
BEING INDICATED BY THE MEDIUM RANGE MODELS AND ENSEMBLE SUITES FOR
FRIDAY THROUGH SUNDAY.
LOWS GENERALLY IN THE 20S WITH HIGHS IN THE 30S.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
A BAND OF LAKE EFFECT SNOW WILL BRING IFR VSBYS AND CIGS TO RME
THROUGH THIS AFTERNOON. THE BAND WILL LIFT NORTH OF RME TONIGHT
THEN WILL COME BACK SOUTH ACROSS THE RME AREA MONDAY MORNING WITH
ANOTHER PERIOD OF IFR VSBYS AND CIGS. THE BAND WILL REMAIN NORTH
OF SYR THROUGH TONIGHT... THEN A PERIOD OF IFR CIGS AND VSBYS WILL
BE POSSIBLE MONDAY MORNING AS THE BAND MOVES BACK TO THE SOUTH.
OTHERWISE... PERIODS OF LIGHT SNOW WILL AFFECT ITH/ELM/BGM THROUGH
THIS AFTERNOON WITH OCCASIONAL IFR VSBYS. THIS LIGHT SNOW WILL END
TOWARD EVENING WITH VFR VSBYS TONIGHT THROUGH MONDAY ALONG WITH
VFR TO OCCASIONAL MVFR CIGS.
MAINLY VFR CONDITIONS CAN BE EXPECTED AT AVP THROUGH MONDAY.
WINDS WILL BE MAINLY FROM THE WEST AT 5 TO 15 KTS TODAY... LESS
THAN 10 KTS TONIGHT AND 5 TO 15 KTS ON MONDAY.
OUTLOOK...
TUE...VFR-MVFR WITH CHC IFR AS STORM SYSTEM SLIDES JUST TO THE
SOUTH...ESPECIALLY AVP AND BGM.
WED...VFR-MVFR WITH CHC IFR IN LAKE SNOW SHOWERS...MAINLY CNTRL NY.
THU...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 6 PM EST MONDAY FOR NYZ009.
&&
$$
SYNOPSIS...JAB
NEAR TERM...JAB
SHORT TERM...JAB
LONG TERM...
AVIATION...MSE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
634 PM EST MON NOV 26 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK ACROSS THE TN VALLEY TONIGHT AS A TROUGH
CROSSES THE EASTERN GREAT LAKES. HIGH PRESSURE WILL BUILD INTO
THE OHIO VALLEY FOR TUESDAY. A WEAK CLIPPER WILL MOVE ACROSS
SOUTHERN ONTARIO WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
ONLY SLIGHT CHANGES FOR EARLY EVENING UPDATE...MAINLY TO ACCOUNT FOR
CURRENT CONDITIONS. HRRR HAS BEST SNOW OCCURRING BY END OF THE
EVENING AROUND CLEVELAND AND OVER THE SNOWBELT WHILE RUC HAS NOTHING
IN THIS AREA. OF COURSE...HRRR ALSO HAS DECENT SNOW OCCURRING OVER
LERI AND NEARBY ASHTABULA AND ERIE CO PA AT THIS TIME SO CONFIDENCE
IN ANYTHING FROM THE HRRR ANY TIME SOON IS OBVIOUSLY VERY LOW.
CLOUDS CONTINUE TO INCREASE AND THICKEN DURING THE EARLY EVENING.
EXPECT LIGHT SNOW TO DEVELOP THE REST OF THE EVENING AND SPREAD
ACROSS MAINLY THE SSE 3/4 OF THE AREA FROM SOME FRONTOGENETIC
FORCING AND LOCALIZED LIFT OVERHEAD. A MID LEVEL TROUGH WILL BE
COMING ACROSS THE RIGHT ENTRANCE REGION OF THE JET. IT WILL END UP
BEING A SHORT DURATION SNOW...MAYBE 4 OR 5 HOURS WORTH AND MOISTURE
WILL BE LIMITED. WILL STILL GO WITH ACCUMULATIONS UP TO AN INCH.
HAVE NOT INCREASED PRECIP CHANCES ANY HIGHER THAN 70 PERCENT IN CASE
IT ENDS UP BEING SO LIGHT IT DOESN`T REALLY ACCUMULATE. MID/UPPER
20S FOR LOWS TONIGHT...BUT WITH CLEARING TAKING PLACE NEAR TOLEDO
TOWARD MORNING...MAY DIP INTO THE LOWER 20S.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
ANY LIGHT SNOW ACROSS THE EAST WILL QUICKLY MOVE OUT AS THE UPPER
TROUGH AXIS CROSSES AND SURFACE HIGH PRESSURE BUILDS INTO THE OHIO
VALLEY. WILL BEGIN TO GET PARTIAL CLEARING ACROSS THE SOUTHWEST.
THE SNOWBELT WILL CONTINUE TO SEE CLOUDS WITH FLOW OFF THE LAKE.
TEMPS WILL STICK IN THE 30S TUESDAY.
CLOUD COVER WILL REMAIN OVER THE GREAT LAKES AS A CLIPPER MAKES
ITS WAY ACROSS ON WEDNESDAY. THIS DOES NOT HAVE MUCH MOISTURE AT
ALL TO WORK WITH. PRECIP CHANCES WILL BE ON THE BACKSIDE OF THIS
SYSTEM WITH A PUSH OF COLDER AIR AND SOME ADDED LAKE MOISTURE.
TEMPS WILL WARM TO NEAR 40 WITH SOUTHWESTERLY FLOW WEDNESDAY. THE
QUICK PASSING OF SYSTEMS WILL CONTINUE AND HIGH PRESSURE WEDNESDAY
NIGHT WILL SHIFT EAST BY THURSDAY. WE START TO GET SOME WARM AIR
ADVECTION SO HAVE HIGHS THURSDAY IN THE 40S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE LONG TERM BEGINS ON FRIDAY WITH THE GFS AND ECMWF LOOKING
SIMILAR...ALTHOUGH THERE REMAIN DIFFERENCES IN THE DETAILS THAT WILL
LIKELY AFFECT THE REGION. FRIDAY BEGINS WITH HIGH PRESSURE FROM
QUEBEC AND ONTARIO SOUTH ACROSS THE EASTERN LAKES TO THE MID
ATLANTIC COAST. REALLY THIS IS A CANADIAN HIGH AND A PACIFIC HIGH
THAT HAVE MORE OR LESS FUSED. BISECTING THE TO CORES HOWEVER WILL
BE A STATIONARY FRONT. THE ISSUE IS EXACTLY WHERE THIS FRONT WILL BE
AND HOW MUCH MOISTURE WILL BE ASSOCIATED WITH IT. A REASONABLE
PLACEMENT BASED ON MODEL WIND FIELD AND TEMPERATURE PACKING WOULD BE
FROM NWRN OHIO TO SWRN PA AT 12Z. MODELS SHOW MOISTURE ACROSS THE
NRN TIER OF COUNTIES SO WILL BRING A LOW CHANCE POP TO THE AREA
FRIDAY. THINKING HOWEVER MOST OF THE AREA WOULD REMAIN DRY AS
SURFACE LOWS ASSOCIATED WITH THE BOUNDARY REMAIN FAR FROM THE AREA.
OVER THE NEXT 24 HOURS THE DOMINANT CANADIAN HIGH MOVES TO THE EAST
COAST OF CANADA WHILE LOW PRESSURE MOVES TO THE NORTHERN PLAINS.
THIS WILL TURN THE FRONT WARM AND BEGIN TO MOVE IT NORTH ACROSS THE
LAKES. BOTH MODELS DEVELOP A SWATH OF DEEP MOISTURE IN THE SOUTHERLY
FLOW OFF THE GULF. THE GFS IS MORE MOIST HERE WHILE THE ECMWF WHILE
MOIST IS SLOWER AND MORE CONSERVATIVE. WILL FOLLOW THE ECMWF WITH
THE BEST RAIN CHANCES LIKELY SATURDAY AND SATURDAY NIGHT. WILL
CONTINUE WITH A CHANCE EAST SUNDAY BUT TIMING WOULD LIKELY BE
MORNING. SUNDAY NIGHT AND MONDAY SURFACE LOW PRESSURE WILL REMAIN IN
THE NRN PLAINS WITH A SOUTHERLY FLOW ACROSS THE OHIO VALLEY. UPPER
HGTS RISE TO BETWEEN 576 AND 580 ACROSS OHIO AS 850MB TEMPS REACH
+8C. SO TEMPS FOR THE FIRST WORK WEEK IN DEC LOOK TO BEGIN ABOVE
NORMAL.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
TOUGH FORECAST TONIGHT WITH PRECIP COVERAGE THE MAIN CHALLENGE.
STARTING TO SEE SOME RETURNS ON RADAR ALONG THE U.S. 30 CORRIDOR.
IT MAY TAKE ANOTHER HOUR OR TWO FOR LOWER LEVELS OF THE ATMOSPHERE
TO SATURATE ENOUGH TO ALLOW SNOW TO REACH THE GROUND. THINK THERE
WILL BE A GOOD 4 TO 6 HOUR PERIOD OF LIGHT SNOW ACROSS THE
SOUTHERN HALF OF THE AREA. PERIODS OF IFR LIKELY AFTER MIDNIGHT.
NORTHERN TAF SITES WILL SEE LESS SNOW AND WOULD BE SURPRISED TO
SEE ANYTHING AT ALL AT KTOL. CIGS IN THE SOUTH SHOULD DIP TO MVFR
AFTER THE SNOW STARTS. RAPID IMPROVEMENT WILL OCCUR TOWARD
DAYBREAK WITH CIGS LIFTING AND THEN DISSIPATING FROM WEST TO EAST
ON TUESDAY. W TO NW FLOW WILL BECOME MAINLY N.
OUTLOOK...POSSIBLE MVFR LINGERING IN THE SNOWBELT TUESDAY
AFTERNOON. NON VFR POSSIBLE AGAIN WEDNESDAY...CONTINUING IN NERN
OHIO AND NWRN PA WEDNESDAY NIGHT. NON VFR AGAIN POSSIBLY FRIDAY.
&&
.MARINE...
THE SMALL CRAFT ADVISORY FOR NEARSHORE WATERS EAST OF
GENEVA-ON-THE-LAKE EXPIRED AT 4 PM WITH WINDS AND WAVES CONTINUING
TO DECREASE OVERNIGHT. HIGH PRESSURE WILL BUILD EAST INTO THE OHIO
VALLEY ON TUESDAY WITH WINDS NEAR 10 KNOTS BACKING FROM NORTHWEST TO
WEST. SOUTHWESTERLY WINDS WILL INCREASE TO 15 TO 25 KNOTS ON
WEDNESDAY AHEAD OF A CLIPPER SYSTEM PASSING NORTH OF THE LAKE. SMALL
CRAFT ADVISORIES WILL LIKELY BE NEEDED EAST OF VERMILION INTO
WEDNESDAY EVENING AS WAVES BUILD TO 5 TO 8 FEET. HIGH PRESSURE WILL
QUICKLY BUILD EAST ACROSS THE LAKE AGAIN FROM WEDNESDAY NIGHT INTO
THURSDAY WITH A BACK DOOR COLD FRONT PUSHING SOUTH ACROSS LAKE ERIE
ON THURSDAY NIGHT.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...TK
AVIATION...KUBINA
MARINE...KEC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
614 PM EST MON NOV 26 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK ACROSS THE TN VALLEY TONIGHT AS A TROUGH
CROSSES THE EASTERN GREAT LAKES. HIGH PRESSURE WILL BUILD INTO
THE OHIO VALLEY FOR TUESDAY. A WEAK CLIPPER WILL MOVE ACROSS
SOUTHERN ONTARIO WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ONLY SLIGHT CHANGES FOR EARLY EVENING UPDATE...MAINLY TO ACCOUNT FOR
CURRENT CONDITIONS. HRRR HAS BEST SNOW OCCURRING BY END OF THE
EVENING AROUND CLEVELAND AND OVER THE SNOWBELT WHILE RUC HAS NOTHING
IN THIS AREA. OF COURSE...HRRR ALSO HAS DECENT SNOW OCCURRING OVER
LERI AND NEARBY ASHTABULA AND ERIE CO PA AT THIS TIME SO CONFIDENCE
IN ANYTHING FROM THE HRRR ANY TIME SOON IS OBVIOUSLY VERY LOW.
CLOUDS CONTINUE TO INCREASE AND THICKEN DURING THE EARLY EVENING.
EXPECT LIGHT SNOW TO DEVELOP THE REST OF THE EVENING AND SPREAD
ACROSS MAINLY THE SSE 3/4 OF THE AREA FROM SOME FRONTOGENETIC
FORCING AND LOCALIZED LIFT OVERHEAD. A MID LEVEL TROUGH WILL BE
COMING ACROSS THE RIGHT ENTRANCE REGION OF THE JET. IT WILL END UP
BEING A SHORT DURATION SNOW...MAYBE 4 OR 5 HOURS WORTH AND MOISTURE
WILL BE LIMITED. WILL STILL GO WITH ACCUMULATIONS UP TO AN INCH.
HAVE NOT INCREASED PRECIP CHANCES ANY HIGHER THAN 70 PERCENT IN CASE
IT ENDS UP BEING SO LIGHT IT DOESN`T REALLY ACCUMULATE. MID/UPPER
20S FOR LOWS TONIGHT...BUT WITH CLEARING TAKING PLACE NEAR TOLEDO
TOWARD MORNING...MAY DIP INTO THE LOWER 20S.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
ANY LIGHT SNOW ACROSS THE EAST WILL QUICKLY MOVE OUT AS THE UPPER
TROUGH AXIS CROSSES AND SURFACE HIGH PRESSURE BUILDS INTO THE OHIO
VALLEY. WILL BEGIN TO GET PARTIAL CLEARING ACROSS THE SOUTHWEST.
THE SNOWBELT WILL CONTINUE TO SEE CLOUDS WITH FLOW OFF THE LAKE.
TEMPS WILL STICK IN THE 30S TUESDAY.
CLOUD COVER WILL REMAIN OVER THE GREAT LAKES AS A CLIPPER MAKES
ITS WAY ACROSS ON WEDNESDAY. THIS DOES NOT HAVE MUCH MOISTURE AT
ALL TO WORK WITH. PRECIP CHANCES WILL BE ON THE BACKSIDE OF THIS
SYSTEM WITH A PUSH OF COLDER AIR AND SOME ADDED LAKE MOISTURE.
TEMPS WILL WARM TO NEAR 40 WITH SOUTHWESTERLY FLOW WEDNESDAY. THE
QUICK PASSING OF SYSTEMS WILL CONTINUE AND HIGH PRESSURE WEDNESDAY
NIGHT WILL SHIFT EAST BY THURSDAY. WE START TO GET SOME WARM AIR
ADVECTION SO HAVE HIGHS THURSDAY IN THE 40S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE LONG TERM BEGINS ON FRIDAY WITH THE GFS AND ECMWF LOOKING
SIMILAR...ALTHOUGH THERE REMAIN DIFFERENCES IN THE DETAILS THAT WILL
LIKELY AFFECT THE REGION. FRIDAY BEGINS WITH HIGH PRESSURE FROM
QUEBEC AND ONTARIO SOUTH ACROSS THE EASTERN LAKES TO THE MID
ATLANTIC COAST. REALLY THIS IS A CANADIAN HIGH AND A PACIFIC HIGH
THAT HAVE MORE OR LESS FUSED. BISECTING THE TO CORES HOWEVER WILL
BE A STATIONARY FRONT. THE ISSUE IS EXACTLY WHERE THIS FRONT WILL BE
AND HOW MUCH MOISTURE WILL BE ASSOCIATED WITH IT. A REASONABLE
PLACEMENT BASED ON MODEL WIND FIELD AND TEMPERATURE PACKING WOULD BE
FROM NWRN OHIO TO SWRN PA AT 12Z. MODELS SHOW MOISTURE ACROSS THE
NRN TIER OF COUNTIES SO WILL BRING A LOW CHANCE POP TO THE AREA
FRIDAY. THINKING HOWEVER MOST OF THE AREA WOULD REMAIN DRY AS
SURFACE LOWS ASSOCIATED WITH THE BOUNDARY REMAIN FAR FROM THE AREA.
OVER THE NEXT 24 HOURS THE DOMINANT CANADIAN HIGH MOVES TO THE EAST
COAST OF CANADA WHILE LOW PRESSURE MOVES TO THE NORTHERN PLAINS.
THIS WILL TURN THE FRONT WARM AND BEGIN TO MOVE IT NORTH ACROSS THE
LAKES. BOTH MODELS DEVELOP A SWATH OF DEEP MOISTURE IN THE SOUTHERLY
FLOW OFF THE GULF. THE GFS IS MORE MOIST HERE WHILE THE ECMWF WHILE
MOIST IS SLOWER AND MORE CONSERVATIVE. WILL FOLLOW THE ECMWF WITH
THE BEST RAIN CHANCES LIKELY SATURDAY AND SATURDAY NIGHT. WILL
CONTINUE WITH A CHANCE EAST SUNDAY BUT TIMING WOULD LIKELY BE
MORNING. SUNDAY NIGHT AND MONDAY SURFACE LOW PRESSURE WILL REMAIN IN
THE NRN PLAINS WITH A SOUTHERLY FLOW ACROSS THE OHIO VALLEY. UPPER
HGTS RISE TO BETWEEN 576 AND 580 ACROSS OHIO AS 850MB TEMPS REACH
+8C. SO TEMPS FOR THE FIRST WORK WEEK IN DEC LOOK TO BEGIN ABOVE
NORMAL.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
UPPER TROF IS APPROACHING FROM THE WEST WHILE MOISTURE IS MOVING
NORTH THROUGH THE LOWER MISSISSIPPI VALLEY AHEAD OF A DEVELOPING
SURFACE LOW. THE DEEP MOISTURE FROM THE SOUTH WILL REACH INTO THE
SOUTHERN PORTION OF THE AREA AS THE UPPER TROF SWINGS THROUGH THE
AREA OVERNIGHT. HAVE FOLLOWED THE NAM12 IN TIMING OF LIGHT SNOW
DEVELOPING ACROSS THE AREA. LEAST AFFECTED WILL BE KTOL WITH MVFR
AND A GOOD CHANCE OF IFR CIGS AND VISIBILITIES MOVING ACROSS THE
SOUTHERN TIER OF TERMINALS FROM FDY THROUGH MFD CAK AND YNG
OVERNIGHT WITH THE LOWEST CONDITIONS LASTING 3 TO 6 HOURS OR SO.
MVFR CIGS WILL LIFT TO VFR MOST PLACES AS THE SYSTEM PULLS EAST
EARLY TUESDAY.
OUTLOOK...POSSIBLE MVFR LINGERING IN THE SNOWBELT TUESDAY
AFTERNOON. NON VFR POSSIBLE AGAIN WEDNESDAY...CONTINUING IN NERN
OHIO AND NWRN PA WEDNESDAY NIGHT. NON VFR AGAIN POSSIBLY FRIDAY.
&&
.MARINE...
THE SMALL CRAFT ADVISORY FOR NEARSHORE WATERS EAST OF
GENEVA-ON-THE-LAKE EXPIRED AT 4 PM WITH WINDS AND WAVES CONTINUING
TO DECREASE OVERNIGHT. HIGH PRESSURE WILL BUILD EAST INTO THE OHIO
VALLEY ON TUESDAY WITH WINDS NEAR 10 KNOTS BACKING FROM NORTHWEST TO
WEST. SOUTHWESTERLY WINDS WILL INCREASE TO 15 TO 25 KNOTS ON
WEDNESDAY AHEAD OF A CLIPPER SYSTEM PASSING NORTH OF THE LAKE. SMALL
CRAFT ADVISORIES WILL LIKELY BE NEEDED EAST OF VERMILION INTO
WEDNESDAY EVENING AS WAVES BUILD TO 5 TO 8 FEET. HIGH PRESSURE WILL
QUICKLY BUILD EAST ACROSS THE LAKE AGAIN FROM WEDNESDAY NIGHT INTO
THURSDAY WITH A BACK DOOR COLD FRONT PUSHING SOUTH ACROSS LAKE ERIE
ON THURSDAY NIGHT.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN/ADAMS
SHORT TERM...OUDEMAN
LONG TERM...TK
AVIATION...TK
MARINE...KEC
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
250 PM CST SUN NOV 25 2012
.DISCUSSION.../ISSUED AT 250 PM CST/
MAIN CHALLENGES TONIGHT LIE IN THE AMOUNT OF CLOUD COVER ACROSS THE
AREA...WITH POTENTIAL IMPACTS ON OVERNIGHT LOWS...AND PRECIPITATION
POTENTIAL IN OUR FAR SOUTHWEST. STRATUS WHICH RESIDED ACROSS THE
AREA EARLIER IN THE DAY HAS NOW DISSIPATED OVER THE ENTIRE CWA.
TEMPERATURES HAVE BEEN A BIT TRICKY WITH BREAKS IN THE CLOUDS
ALLOWING FOR A RELATIVELY RAPID RISE IN TEMPERATURES IN CLEAR
AREAS...THEN TEMPERED BACK OR FALLING SLIGHTLY WITH THE RETURN OF
CLOUDS. CLOUDS ARE BEGINNING TO FILL BACK IN WITH TWO AREAS
CONVERGING FROM THE NORTH AND SOUTH...MID CLOUDS ACROSS THE SOUTH
AND LOWER CLOUDS DROPPING SOUTHWARD OUT OF NORTH DAKOTA AND NORTHERN
SOUTH DAKOTA AT THIS TIME. MAY SEE A RETURN OF STRATUS...AT LEAST IN
OUR EAST TONIGHT...WITH GFS/NAM/AND RAP INDICATING THE PREVIOUSLY
MENTIONED STRATUS TO OUR NORTH ADVECTING SOUTHWARD ON A
NORTH/NORTHWESTERLY LOW LEVEL FLOW.
WHILE WE DID HAVE A COOLER DAY ACROSS THE AREA...EVEN COLDER AIR IS
POISED TO DRAIN INTO THE REGION TONIGHT BEHIND A SHORTWAVE TRACKING
THROUGH THE UPPER MIDWEST AND INTO THE GREAT LAKES REGION OVERNIGHT.
WITH THIS...WE WILL SEE MUCH COLDER LOWS TONIGHT...MADE SOMEWHAT
CHALLENGING BY WHEN/WHERE THERE IS CLOUD COVER TONIGHT. WITH WINDS
REMAINING FAIRLY LIGHT OVERNIGHT...IF ANY CLEARING TAKES PLACE
READINGS WILL DROP RATHER QUICKLY. AT THIS POINT...HAVE LOWS IN THE
LOWER TEENS NORTH...WHERE COLD AIR ADVECTION WILL BE MOST REALIZED
OVERNIGHT...TO THE LOWER 20S THROUGH OUR FAR SOUTH.
AS FAR AS PRECIPITATION POTENTIAL...RADAR IMAGES HAVE SHOWN RETURNS
THROUGH MUCH OF THE DAY FROM SOUTHWESTERN SOUTH DAKOTA INTO
NORTHEASTERN NEBRASKA...INCLUDING OUR FAR SOUTHERN MISSOURI RIVER
CORRIDOR ZONES...IN THE VICINITY OF A MIDLEVEL BOUNDARY...THOUGH
WITH LOW LEVEL DRY AIR IN PLACE THE ONLY LOCALES REPORTING
PRECIPITATION THUS FAR HAVE BEEN OVER SOUTHWESTERN SOUTH DAKOTA AND
NORTH CENTRAL NEBRASKA. KEPT ONLY SMALL CHANCE POPS IN OUR
SOUTHWESTERN AREAS AS A SHORTWAVE TRACKS OUT OF THE NORTHERN ROCKIES
OVERNIGHT...THOUGH STILL APPEARS THAT THE MIDLEVEL BOUNDARY WILL
BEGIN TO WEAKEN AND SAG SOUTHWARD LATE BEFORE THE BETTER UPPER LEVEL
SUPPORT MOVES INTO THE REGION.
THE COLDEST THERMAL PROFILES WILL BE DRAPED ACROSS OUR AREA ON
MONDAY...ESPECIALLY IN OUR NORTHEAST...WITH HIGHS RANGING FROM THE
LOWER 20S OVER THAT AREA TO THE LOWER 30S THROUGH THE MISSOURI
RIVER CORRIDOR. ALL MODEL RH TIME SECTIONS SHOWING CLOUDS EVENTUALLY
CLEARING OUT BY MONDAY AFTERNOON...SO SHOULD SEE MOSTLY SUNNY SKIES
BY THAT TIME OVER AT LEAST THE NORTHERN TWO THIRDS OF OUR CWA. /JM
SPLIT JET ACROSS THE US IS EXPECTED TO FOCUS MAINLY ON THE NORTHERN
BRANCH THROUGHOUT THE WEEK AS THE SOUTHERN BRANCH WEAKENS.
THROUGHOUT THE WEEK...THE NORTHERN BRANCH OF THE JET IS EXPECTED TO
BUCKLE NORTH AS NORTHWEST FLOW TRANSITIONS TO ZONAL FLOW IN THE MID
LEVELS OF THE ATMOSPHERE. THIS WOULD TYPICALLY RESULT IN A WARMING
TREND...HOWEVER...CLOUD COVER WILL LIKELY HAVE THE MAIN EFFECT ON
TEMPERATURES.
A WEAK COLD FRONT WILL MOVE THROUGH THE AREA ON TUESDAY AFTERNOON.
BOUNDARY IS MAINLY FOCUSED IN THE LOWER LEVELS WITH LITTLE IN THE
WAY OF COLD AIR BEHIND THE FRONT. STILL APPEARS AS THOUGH SOME
STRATUS MAY WORK INTO THE FORECAST AREA FROM THE NORTH TUESDAY NIGHT
LIMITING RADIATIONAL IMPACT. WITH WEAK FLOW ACROSS THE AREA ON
WEDNESDAY...WILL BE A STRUGGLE FOR AREAS IN THE EAST TO WARM IF
STATUS IS ABLE TO PENETRATE INTO THE FORECAST AREA. FOR NOW...HAVE
COOLED FORECAST HIGHS IN SOUTHWEST MINNESOTA...CLOSE TO 925 HPA
ISOTHERMAL...THOUGH MAY HAVE TO EXPAND THE COOLING AS CONFIDENCE IN
THE STRATUS INCREASES.
WEDNESDAY NIGHT A WEAK BOUNDARY APPROACHES FROM THE WEST WITH NO
UPPER LEVEL SUPPORT. MODELS HINT THAT THE BOUNDARY MAY STALL ACROSS
WESTERN PORTIONS OF THE FORECAST AREA...LEAVING THE EAST IN MILD
SOUTHERLY FLOW. THE EAST MAY STILL BE DEALING WITH STRATUS
CONCERNS...SO HAVE SQUASHED DIURNAL RANGE A BIT THURSDAY INTO
FRIDAY. OVERALL...HAVE A GRADUAL WARMING TREND AS 925 HPA TEMPS
WARM FROM 5 TOWARDS 10 DEGREES C.
MODELS SHOW ANOTHER COLD FRONT MOVING THROUGH THE AREA LATE ON
SATURDAY...THOUGH THE STRENGTH OF THE FRONT IS UNDER DEBATE. RIGHT
NOW...THE GFS IS MUCH WEAKER WITH THE FRONT THAN THE ECMWF. WHILE
THE MID LEVEL PATTERN IS MORE ACTIVE...MOISTURE STILL APPEARS TO BE
QUITE LIMITED SO KEPT DRY FORECAST THROUGH NEXT WEEKEND.
STILL APPEARS AS THOUGH A MORE SIZABLE SYSTEM WILL WORK THROUGH THE
NORTHERN PLAINS EARLY THE FOLLOWING WEEK...THOUGH MODELS HAVE BEEN
TRENDING NORTH OF THE FORECAST AREA WITH THE MIDLEVEL WAVE.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
CHALLENGE CONTINUES TO BE COVERAGE/DURATION OF STRATUS ACROSS THE
AREA. MOST MODELS HAVE NOT BEEN HANDLING IT WELL...THOUGH LEANED
CLOSER TO THE RAP MODEL WHICH HAS HANDLED IT BETTER SINCE LAST
NIGHT. CURRENT OBS SHOWING CLOUDS BEGINNING TO BREAK...AND THINK
THIS WILL CONTINUE THROUGH THE AFTERNOON. WILL HAVE TO WATCH SOME
STRATUS LOCATED TO THE NORTH...THROUGH NORTH DAKOTA/FAR NORTHERN
SOUTH DAKOTA...AS THEY TRAVEL SOUTHWARD ON A NORTH/NORTHWESTERLY LOW
LEVEL FLOW. CONFIDENCE IS SOMEWHAT LOW ON IF THESE CLOUDS WILL HOLD
TOGETHER...SO DID NOT INCLUDE IN THE TAFS. MODELS ALSO HINTING OF
SOME STRATUS REDEVELOPMENT TONIGHT...SO WILL BE SOMETHING TO WATCH
FOR.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1120 AM CST SUN NOV 25 2012
.DISCUSSION.../ISSUED AT 1030 AM CST/
BIGGEST CHALLENGE TODAY REMAINS TO BE HOW LONG STRATUS WILL HOLD
OVER THE AREA. CURRENT OBSERVATIONS/SATELLITE IMAGES REVEAL STRATUS
COVERING THE ENTIRE CWA LATE THIS MORNING...AND WHILE ALMOST ALL
MODELS ARE FINALLY CATCHING ON TO IT...THE RAP HAS HAD THE MOST
CONSISTENCY SINCE LAST NIGHT AND LEANED TOWARD THAT WITH STRATUS
SLOWLY ERODING THROUGH THE DAY. DO SEE SOME THINNING ACROSS OUR
NORTH...THOUGH AM A LITTLE WORRIED ABOUT ADDITIONAL LOW CLOUDS OVER
NORTH DAKOTA WHICH APPEAR TO BE OOZING SOUTHWARD...AND WILL HAVE TO
KEEP WATCH ON THAT THROUGH THE AFTERNOON. IN ANY EVENT...AM
EXPECTING CONSIDERABLE CLOUDINESS THROUGH THE DAY...WITH A FEW PEAKS
OF SUN AT BEST. WITH THE CLOUD COVER...TEMPERATURES HAVE BEEN ONLY
SLOWLY RISING THROUGH THE MORNING...THOUGH THEY STILL APPEAR TO BE
ON TRACK TO EVENTUAL HIGHS IN THE LOWER 30S NORTH TO NEAR 40 SOUTH.
UPDATES OUT.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
CHALLENGE CONTINUES TO BE COVERAGE/DURATION OF STRATUS ACROSS THE
AREA. MOST MODELS HAVE NOT BEEN HANDLING IT WELL...THOUGH LEANED
CLOSER TO THE RAP MODEL WHICH HAS HANDLED IT BETTER SINCE LAST
NIGHT. CURRENT OBS SHOWING CLOUDS BEGINNING TO BREAK...AND THINK
THIS WILL CONTINUE THROUGH THE AFTERNOON. WILL HAVE TO WATCH SOME
STRATUS LOCATED TO THE NORTH...THROUGH NORTH DAKOTA/FAR NORTHERN
SOUTH DAKOTA...AS THEY TRAVEL SOUTHWARD ON A NORTH/NORTHWESTERLY LOW
LEVEL FLOW. CONFIDENCE IS SOMEWHAT LOW ON IF THESE CLOUDS WILL HOLD
TOGETHER...SO DID NOT INCLUDE IN THE TAFS. MODELS ALSO HINTING OF
SOME STRATUS REDEVELOPMENT TONIGHT...SO WILL BE SOMETHING TO WATCH
FOR.
&&
.PREV DISCUSSION.../ISSUED AT 346 AM CST/
PASSAGE OF COLD FRONT HAS AGAIN RESULTED IN FAIRLY WIDESPREAD AREA
OF POST FRONTAL STRATUS ACROSS THE EASTERN DAKOTA AND MINNESOTA. RAP
IS BY FAR THE ONLY SOLUTION THAT HAS ADEQUATELY PORTRAYED THE LOWER
CLOUDS...AND THIS SOLUTION IS ALSO THE MOST DISMAL IN RETAINING
STRATUS FIELD THROUGH THE ENTIRE DAY. THIS SEEMS TO BE A BIT EXTREME
WHEN COMPARING TO SOME PARTIAL CLEARING TRENDS TO THE NORTHWEST...
AND INDICATION OF SOME VERY DRY AIR JUST ABOVE THIS CLOUD DECK.
INVERSION REMAINS FAIRLY STRONG...AND WILL LIKELY TRAP A MAJORITY OF
THIS CLOUD DECK...BUT WILL WORK PARTIAL CLEARING INTO THE NORTHERN
AREAS DURING THE AFTERNOON. CLOUDS IN THE MID LEVEL FRONTAL BOUNDARY
WILL KEEP THE COVERAGE HIGH ACROSS THE SOUTH. HOWEVER...DRY AIR WHICH
CURRENTLY PRECLUDES MUCH OF SOUTHWESTERN SD RADAR RETURNS FROM
REACHING THE GROUND OUTSIDE THE BLACK HILLS...WILL LIKELY HOLD
ENOUGH TO KEEP MAJORITY OF PRECIPITATION OUT OF THE CWA THROUGH THE
LATER TODAY THROUGH EARLY MONDAY TIMEFRAME. FRONTAL CIRCULATION GETS
A LITTLE KICK LATER TONIGHT AS BRITISH COLUMBIA WAVES SLIDES ACROSS
SOUTH DAKOTA...BUT WITH MID LEVEL FRONT AS FAR SOUTH AS IT IS...HARD
TO PICTURE MUCH OF ANY MEASURABLE PRECIPITATION THREAT.
COLDEST LOW LEVEL AIR REMAINS TRAPPED UP BEHIND SECONDARY WAVE
ENERGY WHICH THEN SURGES SOUTHWARD LATER TONIGHT AND ESPECIALLY ON
MONDAY WITH THIRD WAVE CURRENTLY IN BRITISH COLUMBIA SLIDES THROUGH.
TEMPERATURES WITH CLOUDS WILL STRUGGLE TODAY...WITH TEMPS PERHAPS A
SHADE COOLER THAN EARLIER FORECAST. LARGER CHANGE TONIGHT...WITH
STRONGER COLD AIR ADVECTION AGAIN INTO NORTHERN CWA. DESPITE
CLOUDS...SHOULD BE ABLE TO ADVECT THE WAY TO AROUND 10 IN THE
NORTH...AND KEEP LOWER 20S THROUGH THE MISSOURI CORRIDOR. COLD AIR
BECOMES ENTRENCHED ON MONDAY AS SURFACE RIDGE SETTLES IN. QUICK EXIT
OF WAVE WILL ENTICE MID LEVEL BOUNDARY SOUTH QUICKLY IN THE DAY...
WITH JUST A MINIMAL SNOW MENTION IN THE FAR SOUTHWEST. WOULD BE
SURPRISED TO FIND ANYONE WITH A HALF INCH AT THIS POINT IN GREGORY
COUNTY...AND LITTLE OR NONE ELSEWHERE.
PASSAGE OF WAVE SHOULD FINALLY MOTIVATE DECREASE IN CLOUDS DURING
MONDAY...AND THIS MOSTLY CLEAR START ON MONDAY NIGHT WITH CHILLY
RIDGE SETTLING THROUGH SW MN AND NW IA SHOULD ALLOW QUICK DROP...
AND OVERALL A NON DIURNAL TREND WITH INCREASING SOUTH TO SOUTHWEST
GRADIENT.
ANOTHER WAVE PASSING WELL NORTH OF THE AREA IN STRONG NORTHWEST FLOW
ALOFT WILL PUSH ANOTHER COLD FRONT SOUTHWARD TUESDAY AFTERNOON AND
TUESDAY EVENING. THIS SHOULD END UP A BIT MORE OF A GLANCING BLOW
WITH MAIN PUSH OF COLD AIR THROUGH MINNESOTA BY WEDNESDAY MORNING.
ALMOST EVERY FRONT OF LATE HAS BEEN ACCOMPANIED BY A STRATUS PUSH...
AND EXPECT THIS MAY ALSO BE THE CASE ON LATER TUESDAY NIGHT AND
WEDNESDAY. SHOULD NOT HAVE THE STAYING POWER OF RECENT SURGES THOUGH
WITH MORE PROGRESSIVE FEATURES AT LOW LEVELS AS WELL AS DEVELOPING
SOUTHWESTERLY COMPONENT BY LATER WEDNESDAY. WILL BE INTERESTING TO
SEE HOW DISPLACEMENT OF LOW LEVEL COLD AIR PLAYS OUT...WITH 00Z
ECMWF SET TO WARM WELL INTO THE 40S...AND EVEN SOME 50S IN THE FAR
SOUTHWEST.
FOR THE EXTENDED RANGE /WEDNESDAY NIGHT THROUGH SATURDAY/ THE DRY
REGIME LOOKS TO CONTINUE. CHALLENGE CONTINUES TO BE DEGREE OF
SHALLOW COLD INTRUSION AS ANOTHER BOUNDARY EXPECTED TO SLIP
SOUTHWARD WEDNESDAY NIGHT AND THURSDAY. CERTAINLY NOT THE
PRECIPITATION THREAT WHICH CONTINUES TO EVADE THROUGH DAY 7.
COOLING THURSDAY IS PRIMARILY VERY SHALLOW...WITH SOME SOLUTIONS
HARDLY BLINKING AT 850 HPA. MAY BE VERY DIFFICULT TO WARM IN SOME
WESTERN/NORTHERN AREAS ON THURSDAY... WHILE THE SOUTHEAST AHEAD OF
THE WEAK BOUNDARY COULD BE FAIRLY MILD...IF NOT IMPEDED BY STRATUS
DEVELOPMENT. MOST SOLUTIONS THROUGH FRIDAY INDICATE BETWEEN 3 TO 6C
INVERSION STRENGTH FROM 925-850 HPA AS FLOW RETURNS TO SOUTH TO
SOUTHEAST COMPONENT BELOW. THIS COULD MAKE WARMING A CHALLENGE EVEN
ON FRIDAY...AND FOR NOW WILL ADVERTISE ONLY A MODEST WARMING FROM
THURSDAY FOR MOST AREAS...SOMEWHAT MORE TO THE FAR WEST. LOOKS LIKE
THE LARGER POTENTIAL WARMING WILL BE SATURDAY. PERHAPS BY EARLY NEXT
WEEK AS LARGER WESTERN TROUGH BEGINS TO SHIFT EAST...CAN A
SIGNIFICANT PRECIPITATION EVENT EVOLVE. /CHAPMAN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1030 AM CST SUN NOV 25 2012
.DISCUSSION...
BIGGEST CHALLENGE TODAY REMAINS TO BE HOW LONG STRATUS WILL HOLD
OVER THE AREA. CURRENT OBSERVATIONS/SATELLITE IMAGES REVEAL STRATUS
COVERING THE ENTIRE CWA LATE THIS MORNING...AND WHILE ALMOST ALL
MODELS ARE FINALLY CATCHING ON TO IT...THE RAP HAS HAD THE MOST
CONSISTENCY SINCE LAST NIGHT AND LEANED TOWARD THAT WITH STRATUS
SLOWLY ERODING THROUGH THE DAY. DO SEE SOME THINNING ACROSS OUR
NORTH...THOUGH AM A LITTLE WORRIED ABOUT ADDITIONAL LOW CLOUDS OVER
NORTH DAKOTA WHICH APPEAR TO BE OOZING SOUTHWARD...AND WILL HAVE TO
KEEP WATCH ON THAT THROUGH THE AFTERNOON. IN ANY EVENT...AM
EXPECTING CONSIDERABLE CLOUDINESS THROUGH THE DAY...WITH A FEW PEAKS
OF SUN AT BEST. WITH THE CLOUD COVER...TEMPERATURES HAVE BEEN ONLY
SLOWLY RISING THROUGH THE MORNING...THOUGH THEY STILL APPEAR TO BE
ON TRACK TO EVENTUAL HIGHS IN THE LOWER 30S NORTH TO NEAR 40 SOUTH.
UPDATES OUT.
&&
.PREV DISCUSSION.../ISSUED AT 346 AM CST/
PASSAGE OF COLD FRONT HAS AGAIN RESULTED IN FAIRLY WIDESPREAD AREA
OF POST FRONTAL STRATUS ACROSS THE EASTERN DAKOTA AND MINNESOTA. RAP
IS BY FAR THE ONLY SOLUTION THAT HAS ADEQUATELY PORTRAYED THE LOWER
CLOUDS...AND THIS SOLUTION IS ALSO THE MOST DISMAL IN RETAINING
STRATUS FIELD THROUGH THE ENTIRE DAY. THIS SEEMS TO BE A BIT EXTREME
WHEN COMPARING TO SOME PARTIAL CLEARING TRENDS TO THE NORTHWEST...
AND INDICATION OF SOME VERY DRY AIR JUST ABOVE THIS CLOUD DECK.
INVERSION REMAINS FAIRLY STRONG...AND WILL LIKELY TRAP A MAJORITY OF
THIS CLOUD DECK...BUT WILL WORK PARTIAL CLEARING INTO THE NORTHERN
AREAS DURING THE AFTERNOON. CLOUDS IN THE MID LEVEL FRONTAL BOUNDARY
WILL KEEP THE COVERAGE HIGH ACROSS THE SOUTH. HOWEVER...DRY AIR WHICH
CURRENTLY PRECLUDES MUCH OF SOUTHWESTERN SD RADAR RETURNS FROM
REACHING THE GROUND OUTSIDE THE BLACK HILLS...WILL LIKELY HOLD
ENOUGH TO KEEP MAJORITY OF PRECIPITATION OUT OF THE CWA THROUGH THE
LATER TODAY THROUGH EARLY MONDAY TIMEFRAME. FRONTAL CIRCULATION GETS
A LITTLE KICK LATER TONIGHT AS BRITISH COLUMBIA WAVES SLIDES ACROSS
SOUTH DAKOTA...BUT WITH MID LEVEL FRONT AS FAR SOUTH AS IT IS...HARD
TO PICTURE MUCH OF ANY MEASURABLE PRECIPITATION THREAT.
COLDEST LOW LEVEL AIR REMAINS TRAPPED UP BEHIND SECONDARY WAVE
ENERGY WHICH THEN SURGES SOUTHWARD LATER TONIGHT AND ESPECIALLY ON
MONDAY WITH THIRD WAVE CURRENTLY IN BRITISH COLUMBIA SLIDES THROUGH.
TEMPERATURES WITH CLOUDS WILL STRUGGLE TODAY...WITH TEMPS PERHAPS A
SHADE COOLER THAN EARLIER FORECAST. LARGER CHANGE TONIGHT...WITH
STRONGER COLD AIR ADVECTION AGAIN INTO NORTHERN CWA. DESPITE
CLOUDS...SHOULD BE ABLE TO ADVECT THE WAY TO AROUND 10 IN THE
NORTH...AND KEEP LOWER 20S THROUGH THE MISSOURI CORRIDOR. COLD AIR
BECOMES ENTRENCHED ON MONDAY AS SURFACE RIDGE SETTLES IN. QUICK EXIT
OF WAVE WILL ENTICE MID LEVEL BOUNDARY SOUTH QUICKLY IN THE DAY...
WITH JUST A MINIMAL SNOW MENTION IN THE FAR SOUTHWEST. WOULD BE
SURPRISED TO FIND ANYONE WITH A HALF INCH AT THIS POINT IN GREGORY
COUNTY...AND LITTLE OR NONE ELSEWHERE.
PASSAGE OF WAVE SHOULD FINALLY MOTIVATE DECREASE IN CLOUDS DURING
MONDAY...AND THIS MOSTLY CLEAR START ON MONDAY NIGHT WITH CHILLY
RIDGE SETTLING THROUGH SW MN AND NW IA SHOULD ALLOW QUICK DROP...
AND OVERALL A NON DIURNAL TREND WITH INCREASING SOUTH TO SOUTHWEST
GRADIENT.
ANOTHER WAVE PASSING WELL NORTH OF THE AREA IN STRONG NORTHWEST FLOW
ALOFT WILL PUSH ANOTHER COLD FRONT SOUTHWARD TUESDAY AFTERNOON AND
TUESDAY EVENING. THIS SHOULD END UP A BIT MORE OF A GLANCING BLOW
WITH MAIN PUSH OF COLD AIR THROUGH MINNESOTA BY WEDNESDAY MORNING.
ALMOST EVERY FRONT OF LATE HAS BEEN ACCOMPANIED BY A STRATUS PUSH...
AND EXPECT THIS MAY ALSO BE THE CASE ON LATER TUESDAY NIGHT AND
WEDNESDAY. SHOULD NOT HAVE THE STAYING POWER OF RECENT SURGES THOUGH
WITH MORE PROGRESSIVE FEATURES AT LOW LEVELS AS WELL AS DEVELOPING
SOUTHWESTERLY COMPONENT BY LATER WEDNESDAY. WILL BE INTERESTING TO
SEE HOW DISPLACEMENT OF LOW LEVEL COLD AIR PLAYS OUT...WITH 00Z
ECMWF SET TO WARM WELL INTO THE 40S...AND EVEN SOME 50S IN THE FAR
SOUTHWEST.
FOR THE EXTENDED RANGE /WEDNESDAY NIGHT THROUGH SATURDAY/ THE DRY
REGIME LOOKS TO CONTINUE. CHALLENGE CONTINUES TO BE DEGREE OF
SHALLOW COLD INTRUSION AS ANOTHER BOUNDARY EXPECTED TO SLIP
SOUTHWARD WEDNESDAY NIGHT AND THURSDAY. CERTAINLY NOT THE
PRECIPITATION THREAT WHICH CONTINUES TO EVADE THROUGH DAY 7.
COOLING THURSDAY IS PRIMARILY VERY SHALLOW...WITH SOME SOLUTIONS
HARDLY BLINKING AT 850 HPA. MAY BE VERY DIFFICULT TO WARM IN SOME
WESTERN/NORTHERN AREAS ON THURSDAY... WHILE THE SOUTHEAST AHEAD OF
THE WEAK BOUNDARY COULD BE FAIRLY MILD...IF NOT IMPEDED BY STRATUS
DEVELOPMENT. MOST SOLUTIONS THROUGH FRIDAY INDICATE BETWEEN 3 TO 6C
INVERSION STRENGTH FROM 925-850 HPA AS FLOW RETURNS TO SOUTH TO
SOUTHEAST COMPONENT BELOW. THIS COULD MAKE WARMING A CHALLENGE EVEN
ON FRIDAY...AND FOR NOW WILL ADVERTISE ONLY A MODEST WARMING FROM
THURSDAY FOR MOST AREAS...SOMEWHAT MORE TO THE FAR WEST. LOOKS LIKE
THE LARGER POTENTIAL WARMING WILL BE SATURDAY. PERHAPS BY EARLY NEXT
WEEK AS LARGER WESTERN TROUGH BEGINS TO SHIFT EAST...CAN A
SIGNIFICANT PRECIPITATION EVENT EVOLVE. /CHAPMAN
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
MVFR CONDITIONS CAN BE EXPECTED THROUGH A LARGE PORTION OF THE
PERIOD AS WIDESPREAD STRATUS HAS DEVELOPED IN BEHIND THE COLD FRONT
THAT PASSED THROUGH THE TAF SITES LAST NIGHT. RUC KEEPS LOW CLOUDS
IN FOR A LONGER TIME PERIOD THAN OTHER MODELS. FEEL MVFR CIGS
SHOULD START BREAKING UP AT 20Z. VFR CONDITIONS WILL DEVELOP AFTER
THAT TIME - 20Z. NORTHERLY WINDS OF 10 TO 15 MPH CAN BE EXPECTED.
/HEITKAMP
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
346 AM CST SUN NOV 25 2012
.DISCUSSION.../ISSUED AT 346 AM CST/
PASSAGE OF COLD FRONT HAS AGAIN RESULTED IN FAIRLY WIDESPREAD AREA
OF POST FRONTAL STRATUS ACROSS THE EASTERN DAKOTA AND MINNESOTA. RAP
IS BY FAR THE ONLY SOLUTION THAT HAS ADEQUATELY PORTRAYED THE LOWER
CLOUDS...AND THIS SOLUTION IS ALSO THE MOST DISMAL IN RETAINING
STRATUS FIELD THROUGH THE ENTIRE DAY. THIS SEEMS TO BE A BIT EXTREME
WHEN COMPARING TO SOME PARTIAL CLEARING TRENDS TO THE NORTHWEST...
AND INDICATION OF SOME VERY DRY AIR JUST ABOVE THIS CLOUD DECK.
INVERSION REMAINS FAIRLY STRONG...AND WILL LIKELY TRAP A MAJORITY OF
THIS CLOUD DECK...BUT WILL WORK PARTIAL CLEARING INTO THE NORTHERN
AREAS DURING THE AFTERNOON. CLOUDS IN THE MID LEVEL FRONTAL BOUNDARY
WILL KEEP THE COVERAGE HIGH ACROSS THE SOUTH. HOWEVER...DRY AIR WHICH
CURRENTLY PRECLUDES MUCH OF SOUTHWESTERN SD RADAR RETURNS FROM
REACHING THE GROUND OUTSIDE THE BLACK HILLS...WILL LIKELY HOLD
ENOUGH TO KEEP MAJORITY OF PRECIPITATION OUT OF THE CWA THROUGH THE
LATER TODAY THROUGH EARLY MONDAY TIMEFRAME. FRONTAL CIRCULATION GETS
A LITTLE KICK LATER TONIGHT AS BRITISH COLUMBIA WAVES SLIDES ACROSS
SOUTH DAKOTA...BUT WITH MID LEVEL FRONT AS FAR SOUTH AS IT IS...HARD
TO PICTURE MUCH OF ANY MEASURABLE PRECIPITATION THREAT.
COLDEST LOW LEVEL AIR REMAINS TRAPPED UP BEHIND SECONDARY WAVE
ENERGY WHICH THEN SURGES SOUTHWARD LATER TONIGHT AND ESPECIALLY ON
MONDAY WITH THIRD WAVE CURRENTLY IN BRITISH COLUMBIA SLIDES THROUGH.
TEMPERATURES WITH CLOUDS WILL STRUGGLE TODAY...WITH TEMPS PERHAPS A
SHADE COOLER THAN EARLIER FORECAST. LARGER CHANGE TONIGHT...WITH
STRONGER COLD AIR ADVECTION AGAIN INTO NORTHERN CWA. DESPITE
CLOUDS...SHOULD BE ABLE TO ADVECT THE WAY TO AROUND 10 IN THE
NORTH...AND KEEP LOWER 20S THROUGH THE MISSOURI CORRIDOR. COLD AIR
BECOMES ENTRENCHED ON MONDAY AS SURFACE RIDGE SETTLES IN. QUICK EXIT
OF WAVE WILL ENTICE MID LEVEL BOUNDARY SOUTH QUICKLY IN THE DAY...
WITH JUST A MINIMAL SNOW MENTION IN THE FAR SOUTHWEST. WOULD BE
SURPRISED TO FIND ANYONE WITH A HALF INCH AT THIS POINT IN GREGORY
COUNTY...AND LITTLE OR NONE ELSEWHERE.
PASSAGE OF WAVE SHOULD FINALLY MOTIVATE DECREASE IN CLOUDS DURING
MONDAY...AND THIS MOSTLY CLEAR START ON MONDAY NIGHT WITH CHILLY
RIDGE SETTLING THROUGH SW MN AND NW IA SHOULD ALLOW QUICK DROP...
AND OVERALL A NON DIURNAL TREND WITH INCREASING SOUTH TO SOUTHWEST
GRADIENT.
ANOTHER WAVE PASSING WELL NORTH OF THE AREA IN STRONG NORTHWEST FLOW
ALOFT WILL PUSH ANOTHER COLD FRONT SOUTHWARD TUESDAY AFTERNOON AND
TUESDAY EVENING. THIS SHOULD END UP A BIT MORE OF A GLANCING BLOW
WITH MAIN PUSH OF COLD AIR THROUGH MINNESOTA BY WEDNESDAY MORNING.
ALMOST EVERY FRONT OF LATE HAS BEEN ACCOMPANIED BY A STRATUS PUSH...
AND EXPECT THIS MAY ALSO BE THE CASE ON LATER TUESDAY NIGHT AND
WEDNESDAY. SHOULD NOT HAVE THE STAYING POWER OF RECENT SURGES THOUGH
WITH MORE PROGRESSIVE FEATURES AT LOW LEVELS AS WELL AS DEVELOPING
SOUTHWESTERLY COMPONENT BY LATER WEDNESDAY. WILL BE INTERESTING TO
SEE HOW DISPLACEMENT OF LOW LEVEL COLD AIR PLAYS OUT...WITH 00Z
ECMWF SET TO WARM WELL INTO THE 40S...AND EVEN SOME 50S IN THE FAR
SOUTHWEST.
FOR THE EXTENDED RANGE /WEDNESDAY NIGHT THROUGH SATURDAY/ THE DRY
REGIME LOOKS TO CONTINUE. CHALLENGE CONTINUES TO BE DEGREE OF
SHALLOW COLD INTRUSION AS ANOTHER BOUNDARY EXPECTED TO SLIP
SOUTHWARD WEDNESDAY NIGHT AND THURSDAY. CERTAINLY NOT THE
PRECIPITATION THREAT WHICH CONTINUES TO EVADE THROUGH DAY 7.
COOLING THURSDAY IS PRIMARILY VERY SHALLOW...WITH SOME SOLUTIONS
HARDLY BLINKING AT 850 HPA. MAY BE VERY DIFFICULT TO WARM IN SOME
WESTERN/NORTHERN AREAS ON THURSDAY... WHILE THE SOUTHEAST AHEAD OF
THE WEAK BOUNDARY COULD BE FAIRLY MILD...IF NOT IMPEDED BY STRATUS
DEVELOPMENT. MOST SOLUTIONS THROUGH FRIDAY INDICATE BETWEEN 3 TO 6C
INVERSION STRENGTH FROM 925-850 HPA AS FLOW RETURNS TO SOUTH TO
SOUTHEAST COMPONENT BELOW. THIS COULD MAKE WARMING A CHALLENGE EVEN
ON FRIDAY...AND FOR NOW WILL ADVERTISE ONLY A MODEST WARMING FROM
THURSDAY FOR MOST AREAS...SOMEWHAT MORE TO THE FAR WEST. LOOKS LIKE
THE LARGER POTENTIAL WARMING WILL BE SATURDAY. PERHAPS BY EARLY NEXT
WEEK AS LARGER WESTERN TROUGH BEGINS TO SHIFT EAST...CAN A
SIGNIFICANT PRECIPITATION EVENT EVOLVE. /CHAPMAN
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
MVFR CONDITIONS CAN BE EXPECTED THROUGH A LARGE PORTION OF THE
PERIOD AS WIDESPREAD STRATUS HAS DEVELOPED IN BEHIND THE COLD FRONT
THAT PASSED THROUGH THE TAF SITES LAST NIGHT. RUC KEEPS LOW CLOUDS
IN FOR A LONGER TIME PERIOD THAN OTHER MODELS. FEEL MVFR CIGS
SHOULD START BREAKING UP AT 20Z. VFR CONDITIONS WILL DEVELOP AFTER
THAT TIME - 20Z. NORTHERLY WINDS OF 10 TO 15 MPH CAN BE EXPECTED.
/HEITKAMP
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
540 PM CST MON NOV 26 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A 1033MB HIGH
PRESSURE SYSTEM MOVING SOUTHEAST OVER THE NORTH-CENTRAL GREAT
PLAINS. NORTHWEST FLOW ALONG THE THE FRONT SIDE OF THE HIGH
CONTINUES TO PRODUCE LAKE CLOUDS AND FLURRIES OVER N-C WISCONSIN
EARLY THIS AFTERNOON...BUT THESE CLOUDS SHOULD START TO ERODE LATER
IN THE DAY AS THE SURFACE HIGH BRINGS DRIER AIR INTO THE STATE. LOW
LEVEL WARM ADVECTION IS OCCURRING UPSTREAM OVER NORTH DAKOTA AND
SOUTHERN CANADA WHERE THERE ARE A FEW REPORTS OF SNOW SHOWERS AND
FLURRIES. AS THIS WARM ADVECTION ARRIVES LATE TONIGHT INTO
TUESDAY...CLOUDS AND SNOW CHANCES ARE THE MAIN FORECAST CONCERNS.
TONIGHT...NORTHWEST FLOW TO PREVAIL TONIGHT ACROSS THE WESTERN GREAT
LAKES. WEAK SHORTWAVE EMBEDDED WITHIN THE FLOW WILL PASS OVER
NORTHERN ILLINOIS THIS EVENING WHILE HIGH PRESSURE PASSES ACROSS THE
STATE OF WISCONSIN. AS LOW LEVEL WINDS BACK AROUND TO THE
WEST...THEY WILL PUSH DRIER AIR ACROSS NORTHERN WISCONSIN AND LAKE
EFFECT CLOUDS SHOULD EXIT TO THE NORTHEAST. SO SHOULD HAVE A MOSTLY
CLEAR EVENING AND WINDS HAVE A CHANCE TO DECOUPLE...WHICH WOULD HELP
TEMPS PLUMMET OVER N-C WISCONSIN ONCE SKIES CLEAR. TEMPS UPSTREAM
IN MINNESOTA FELL NEAR ZERO...AND THINK POTENTIAL IS THERE FOR THAT
TO OCCUR. WILL TREND TEMPS LOWER. AFTER MIDNIGHT...A WEAK
SHORTWAVE WILL DROP SOUTHEAST ACROSS SOUTHERN CANADA AND WILL SEND
SCT-BKN LOW AND MID CLOUDS ACROSS THE NORTHWEST PART OF THE STATE.
FLURRIES NOTED OVER SOUTH-CENTRAL CANADA SHOULD STAY TO OUR NORTH.
ONCE THE CLOUDS ARRIVE...TEMPS MAY REBOUND A BIT. LOWS IN THE MID
SINGLE DIGITS NORTH TO THE UPPER TEENS NEAR LAKE MICHIGAN.
TUESDAY...THE SHORTWAVE ENERGY WILL DROP INTO THE WESTERN GREAT
LAKES ON TUESDAY AND WILL PUSH A COLD FRONT INTO NORTHWEST WISCONSIN
DURING THE AFTERNOON. LOW LEVEL WARM ADVECTION CLOUDS WILL LIKELY
LIFT OUT TO THE NORTHEAST IN THE MORNING. PLENTY OF MID AND HIGH
CLOUDS WILL BE AROUND TO MAKE THIS A PARTLY SUNNY TO MOSTLY CLOUDY
DAY. AHEAD OF THE FRONT...LOW CLOUDS WILL BE ON THE INCREASE OVER
N-C AND CENTRAL WISCONSIN IN THE AFTERNOON. PREVIOUS SHIFT ADDED A
CHANCE OF SNOW SHOWERS...AND THIS LOOKS GOOD. HIGHS IN THE MIDDLE
20S NORTH TO THE LOWER 30S SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY. LOOKS LIKE A
FAIRLY QUITE PERIOD OF WEATHER WITH LITTLE OR NO SNOW AND
TEMPERATURES WARMING ABOVE NORMAL.
NORTHWEST UPPER FLOW WILL KEEP TEMPERATURES NEAR NORMAL WEDNESDAY
BUT THEN UPPER FLOW WILL BACK AND BECOME ZONAL BY THE END OF THE
WEEK. A COUPLE OF WEAK SHORTWAVES ARE EXPECTED TO MOVE THROUGH
THE UPPER FLOW FRIDAY AND SATURDAY SETTING UP SOME LIGHT
OVERRUNNING PRECIPITATION. IT MAY BE COLD ENOUGH FOR SOME SNOW
FRIDAY BUT AFTER THAT IT LOOKS TOO WARM FOR ANYTHING BUT LIGHT
RAIN.
SOUTHERLY SURFACE FLOW WILL BRING UP WARM AND MOIST AIR OVER THE
COLD GROUND AND MAY PRODUCE DENSE FOG AT SOME POINT LATE IN THE
WEEK.
&&
.AVIATION...A SMALL PATCH OF MVFR CIGS OVER FAR NE WI WILL BREAK
UP OR MOVE INTO UPPER MICHIGAN EARLY THIS EVG...AS A RIDGE OF HIGH
PRESSURE MOVES INTO THE REGION. MOSTLY CLEAR SKIES WILL GIVE WAY
TO INCREASING CLOUDS AFTER MIDNIGHT. CIGS UPSTREAM OVER NORTHERN
MINNESOTA ARE MAINLY VFR...AND OBSERVATIONS SHOW PATCHY LIGHT
SNOW OR FLURRIES. HAVE OPTED TO ADD A MENTION OF FLURRIES FOR THE
RHI TAF SITE LATE TONIGHT INTO EARLY TUESDAY. SCT-BKN MID-LEVEL
CLOUDS ARE EXPECTED TUESDAY AFTERNOON...ALONG WITH SW WINDS GUSTING
TO NEAR 20 KTS.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1100 AM CST SUN NOV 25 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
305 AM CST SUN NOV 25 2012
MAIN FORECAST CONCERNS ARE ON CLOUDS THROUGH THE PERIOD AND
TEMPERATURES.
07Z SURFACE ANALYSIS SHOWS TROUGH RUNNING FROM SOUTH CENTRAL
MINNESOTA...INTO NORTHWEST WISCONSIN. LARGE SHIELD OF STRATO-CUMULUS
SEEN BEHIND IT EXTENDING ALL THE WAY INTO THE DAKOTAS...MOVING
SOUTHEAST TOWARDS THE AREA. SNOW ACROSS CLARK AND TAYLOR COUNTIES
WAS EXITING EASTWARD.
25.00Z MODELS STRUGGLING WITH HANDING OF THE NEAR TERM
STRATO-CUMULUS DECK...WITH THE RAP DOING THE BEST.
OTHERWISE...MODELS IN GOOD AGREEMENT THROUGH THE REMAINDER OF THE
PERIOD.
IN THE NEAR TERM...25.03Z RAP RELATIVE HUMIDITY PROGS SHOW STRATUS
FIELD OVER MINNESOTA TO PUSH ACROSS THE FORECAST AREA TODAY IN THE
WAKE OF THE SURFACE TROUGH. 25.12Z NAM ON THE OTHER HAND SHOWS THIS
STRATUS OVER MAINLY THE NORTHERN SECTIONS. RAP VERIFYING BEST AT 07Z
AND THUS GOING FOR THE MORE PESSIMISTIC CLOUD FORECAST TODAY...WITH
MOSTLY CLOUDY SKIES. WITH THE CLOUDS AND 925MB-700MB COLD
ADVECTION...TEMPERATURES WILL NOT REBOUND MUCH FROM MORNING LOWS AND
THUS DID COOL TEMPERATURES A FEW DEGREES FROM THE PREVIOUS FORECAST
AND THIS INLINE WITH GUIDANCE TRENDS OF BEING COOLER.
HIGH PRESSURE BEGINS TO BUILD INTO THE NORTHERN PLAINS/MINNESOTA
TONIGHT. AS DRIER AIR ADVECTS INTO THE REGION DO EXPECT THE CLOUDS
TO BREAK UP SOMEWHAT...WITH SOME CLEARING LIKELY AS THE NIGHT WEARS
ON. SOME CONCERN THAT LOW LEVEL MOISTURE WILL GET TRAPPED UNDER THE
INVERSION AND THUS SEE VERY LITTLE CLEARING. ALSO CANNOT RULE OUT A
FEW FLURRIES THIS EVENING...BUT DID NOT INCLUDE IN THE GRIDS AT THIS
TIME. EXPECT TEMPERATURES TO DROP INTO THE TEENS...AND PERHAPS A
LITTLE COLDER IN AREAS WHERE SKIES WOULD CLEAR.
THE HIGH THEN SETTLES OVERHEAD MONDAY AND MONDAY NIGHT. WITH
850MB TEMPERATURES RANGING FROM -5 DEGREES ACROSS THE FAR SOUTH TO
-12 DEGREES IN THE NORTH...EXPECT THIS TO BE THE COLDEST DAY OF
THE WEEK...WITH HIGHS ONLY IN THE 20S.
THE HIGH WILL TRANSLATE TO THE SOUTHEAST ON TUESDAY...WITH WARM
ADVECTION ON ITS BACK SIDE AS WINDS COME AROUND TO THE SOUTHWEST.
WITH THE 850MB-700MB WARM ADVECTION...A BAND OF MID LEVEL CLOUDS ARE
EXPECTED TO TRAVERSE THE AREA. WITH 850MB TEMPERATURES IN THE -5 TO
-8 DEGREES CELSIUS RANGE...EXPECT HIGHS IN THE UPPER 20S TO MIDDLE
30S. A SHORTWAVE WILL TRANSLATE ACROSS LAKE SUPERIOR LATE IN THE
DAY...DRAGGING A WEAK SURFACE TROUGH THROUGH THE AREA. THIS WILL BE
NO MORE THAN A WIND SHIFT...WITH ANT PRECIPITATION REMAINING WELL TO
THE NORTH OF THE AREA NEAR THE MAIN WAVE. THE SOUTHWESTERLY WINDS
WILL KEEP TEMPERATURES FROM BOTTOMING OUT TUESDAY NIGHT...WITH LOWS
IN THE TEENS AND 20S.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
305 AM CST SUN NOV 25 2012
NORTHWESTERLY FLOW WITH HIGH PRESSURE AT THE SURFACE ON WEDNESDAY
WILL GIVE WAY TO A MORE ZONAL FLOW FROM THURSDAY THROUGH SATURDAY.
25.00Z GFS AND ECMWF DO DIFFER IN THEIR SOLUTIONS IN HANDLING THE
VARIOUS SHORTWAVES MOVING THROUGH THE FLOW. GFS DEPICTS A SHORTWAVE
IN THE FLOW OVER THE CENTRAL PLAINS ON THURSDAY...WHILE THE ECMWF IS
MUCH WEAKER AND FURTHER SOUTH OVER TEXAS. IN EITHER CASE...SOME
TRANSPORT OF LOW LEVEL MOISTURE MAY WORK ITS WAY NORTHWARD INTO
EASTERN IOWA AND SOUTHERN WISCONSIN THURSDAY NIGHT AND BRING A
SLIGHT CHANCE FOR SOME LIGHT PRECIPITATION TO THE AREA.
OTHERWISE...REMAINDER OF THE FORECAST PERIOD LOOKS DRY...WITH A
GRADUAL WARMING TREND INTO THE WEEKEND. IN FACT BOTH THE ECMWF AND
GFS ARE SHOWING 850MB TEMPERATURES RISING TO 8 TO 10 DEGREES
CELSIUS SATURDAY. THUS EXPECT TEMPERATURES TO WARM INTO THE MIDDLE
TO UPPER 40S AND PERHAPS 50 IN A FEW LOCATIONS.
&&
.AVIATION...
1100 AM CST SUN NOV 25 2012
AVIATION CONCERNS FOCUS ON THE LOW MVFR STRATUS DECK...HOW LONG IT
WILL LINGER ACROSS THE REGION. LATEST SATELLITE IMAGERY DEPICTS A
BROAD AREA OF LOW STRATUS...MAKING A SLOW PUSH SOUTHEAST ACROSS THE
REGION. SFC OBS UNDER THE CLOUDS PLACED CIG HEIGHTS FROM 1.5-2 KFT.
PIREPS AND VISUAL ID OF THE LAYER SHOWED IT WAS FAIRLY
SHALLOW...ABOUT 1 KFT IN DEPTH. RAP13/NAM12 FAVOR KEEPING THE LOW
RH/CLOUDS ACROSS THE AREA TONIGHT...WITH SUGGESTIONS FROM THE NAM12
THAT IT WOULD HOLD INTO TUE. HOWEVER...SFC WINDS HAVE INCREASED AND
BUFKIT SOUNDINGS PROMOTE MIXING BELOW AN INVERSION AROUND 900 MB.
SO...SEE THE POTENTIAL FOR EROSION OF THE LEADING EDGE OF THE
CLOUDS...ALONG WITH HOLES OPENING UP ELSEWHERE. INDICATION THAT THIS
IS ALREADY HAPPENING IN MOST RECENT SATELLITE IMAGERY. WILL GO WITH
A MIX OF SCT-BKN CONDITIONS FOR THIS AFTERNOON. WOULD EXPECT THE
STRATUS TO FILL IN ANY HOLES LATER TONIGHT...ALA THE BUFKIT
SOUNDINGS. NORTH-SOUTH RUNNING TIME/HEIGHT X-SECTIONS KEEP THE LOW
SATURATION THROUGH MONDAY...BUT SHOW SOME EROSION ON THE SOUTHERN
EXTENT...LIKE TODAY. WILL LEAN TOWARD THE PESSIMISTIC BKN MVFR CIGS
FOR NOW...BUT COULD SEE A BREAKOUT INTO SCT SKIES IN THE AFTERNOON
MON FROM MIXING/DRYING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
305 AM CST SUN NOV 25 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM....RABERDING
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
533 AM CST SUN NOV 25 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
305 AM CST SUN NOV 25 2012
MAIN FORECAST CONCERNS ARE ON CLOUDS THROUGH THE PERIOD AND
TEMPERATURES.
07Z SURFACE ANALYSIS SHOWS TROUGH RUNNING FROM SOUTH CENTRAL
MINNESOTA...INTO NORTHWEST WISCONSIN. LARGE SHIELD OF STRATO-CUMULUS
SEEN BEHIND IT EXTENDING ALL THE WAY INTO THE DAKOTAS...MOVING
SOUTHEAST TOWARDS THE AREA. SNOW ACROSS CLARK AND TAYLOR COUNTIES
WAS EXITING EASTWARD.
25.00Z MODELS STRUGGLING WITH HANDING OF THE NEAR TERM
STRATO-CUMULUS DECK...WITH THE RAP DOING THE BEST.
OTHERWISE...MODELS IN GOOD AGREEMENT THROUGH THE REMAINDER OF THE
PERIOD.
IN THE NEAR TERM...25.03Z RAP RELATIVE HUMIDITY PROGS SHOW STRATUS
FIELD OVER MINNESOTA TO PUSH ACROSS THE FORECAST AREA TODAY IN THE
WAKE OF THE SURFACE TROUGH. 25.12Z NAM ON THE OTHER HAND SHOWS THIS
STRATUS OVER MAINLY THE NORTHERN SECTIONS. RAP VERIFYING BEST AT 07Z
AND THUS GOING FOR THE MORE PESSIMISTIC CLOUD FORECAST TODAY...WITH
MOSTLY CLOUDY SKIES. WITH THE CLOUDS AND 925MB-700MB COLD
ADVECTION...TEMPERATURES WILL NOT REBOUND MUCH FROM MORNING LOWS AND
THUS DID COOL TEMPERATURES A FEW DEGREES FROM THE PREVIOUS FORECAST
AND THIS INLINE WITH GUIDANCE TRENDS OF BEING COOLER.
HIGH PRESSURE BEGINS TO BUILD INTO THE NORTHERN PLAINS/MINNESOTA
TONIGHT. AS DRIER AIR ADVECTS INTO THE REGION DO EXPECT THE CLOUDS TO
BREAK UP SOMEWHAT...WITH SOME CLEARING LIKELY AS THE NIGHT WEARS
ON. SOME CONCERN THAT LOW LEVEL MOISTURE WILL GET TRAPPED UNDER
THE INVERSION AND THUS SEE VERY LITTLE CLEARING. ALSO CANNOT RULE
OUT A FEW FLURRIES THIS EVENING...BUT DID NOT INCLUDE IN THE GRIDS
AT THIS TIME. EXPECT TEMPERATURES TO DROP INTO THE TEENS...AND
PERHAPS A LITTLE COLDER IN AREAS WHERE SKIES WOULD CLEAR.
THE HIGH THEN SETTLES OVERHEAD MONDAY AND MONDAY NIGHT. WITH
850MB TEMPERATURES RANGING FROM -5 DEGREES ACROSS THE FAR SOUTH TO
-12 DEGREES IN THE NORTH...EXPECT THIS TO BE THE COLDEST DAY OF
THE WEEK...WITH HIGHS ONLY IN THE 20S.
THE HIGH WILL TRANSLATE TO THE SOUTHEAST ON TUESDAY...WITH WARM
ADVECTION ON ITS BACK SIDE AS WINDS COME AROUND TO THE SOUTHWEST.
WITH THE 850MB-700MB WARM ADVECTION...A BAND OF MID LEVEL CLOUDS ARE
EXPECTED TO TRAVERSE THE AREA. WITH 850MB TEMPERATURES IN THE -5 TO
-8 DEGREES CELSIUS RANGE...EXPECT HIGHS IN THE UPPER 20S TO MIDDLE
30S. A SHORTWAVE WILL TRANSLATE ACROSS LAKE SUPERIOR LATE IN THE
DAY...DRAGGING A WEAK SURFACE TROUGH THROUGH THE AREA. THIS WILL BE
NO MORE THAN A WIND SHIFT...WITH ANT PRECIPITATION REMAINING WELL TO
THE NORTH OF THE AREA NEAR THE MAIN WAVE. THE SOUTHWESTERLY WINDS
WILL KEEP TEMPERATURES FROM BOTTOMING OUT TUESDAY NIGHT...WITH LOWS
IN THE TEENS AND 20S.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
305 AM CST SUN NOV 25 2012
NORTHWESTERLY FLOW WITH HIGH PRESSURE AT THE SURFACE ON WEDNESDAY
WILL GIVE WAY TO A MORE ZONAL FLOW FROM THURSDAY THROUGH SATURDAY.
25.00Z GFS AND ECMWF DO DIFFER IN THEIR SOLUTIONS IN HANDLING THE
VARIOUS SHORTWAVES MOVING THROUGH THE FLOW. GFS DEPICTS A SHORTWAVE
IN THE FLOW OVER THE CENTRAL PLAINS ON THURSDAY...WHILE THE ECMWF IS
MUCH WEAKER AND FURTHER SOUTH OVER TEXAS. IN EITHER CASE...SOME
TRANSPORT OF LOW LEVEL MOISTURE MAY WORK ITS WAY NORTHWARD INTO
EASTERN IOWA AND SOUTHERN WISCONSIN THURSDAY NIGHT AND BRING A
SLIGHT CHANCE FOR SOME LIGHT PRECIPITATION TO THE AREA.
OTHERWISE...REMAINDER OF THE FORECAST PERIOD LOOKS DRY...WITH A
GRADUAL WARMING TREND INTO THE WEEKEND. IN FACT BOTH THE ECMWF AND
GFS ARE SHOWING 850MB TEMPERATURES RISING TO 8 TO 10 DEGREES
CELSIUS SATURDAY. THUS EXPECT TEMPERATURES TO WARM INTO THE MIDDLE
TO UPPER 40S AND PERHAPS 50 IN A FEW LOCATIONS.
&&
.AVIATION...TODAY AND TONIGHT
533 AM CST SUN NOV 25 2012
IR SATELLITE SHOWING AN EXPANSIVE MVFR STRATOCUMULUS FIELD
EXTENDING FROM ALONG I-90 NORTHWARD ALL THE WAY UP INTO SOUTHERN
MANITOBA. RAP MODEL LATCHED ONTO THIS CLOUD VERY WELL PER THE
0.5KM RELATIVE HUMIDITY FIELD. THIS MOISTURE/MVFR STRATOCUMULUS
FIELD WILL CONTINUE TO SPILL INTO THE AREA TODAY AND REMAIN TRAPPED
UNDER A SUBSIDENCE INVERSION. THIS SHOULD KEEP THE CLOUDS
ENTRENCHED ACROSS THE AREA THROUGH TONIGHT. HAVE TRENDED THE
25.12Z TAFS MORE PESSIMISTIC/CLOUDY BASED ON THIS SIGNAL. MODELS
ALSO INDICATING A MID-LEVEL TROUGH DROPPING INTO THE AREA THIS
EVENING WHICH COULD SQUEEZE OUT A FEW FLURRIES FROM TIME TO TIME.
MOST OF THE FORCING FROM THIS MID-LEVEL WAVE LOOKS TO BE NORTH OF
THE AREA...SO NOT CONFIDENT ENOUGH AT THIS TIME TO INCLUDE IN THE
TAFS...BUT WILL PASS ONTO THE DAYSHIFT TO ASSESS FURTHER.
OTHERWISE...LOOK FOR A NORTHWEST SURFACE FLOW THROUGH THE PERIOD
WITH SOME GUSTINESS IN THE 15 TO 25 MPH RANGE DURING THE DAY
TODAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
305 AM CST SUN NOV 25 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
305 AM CST SUN NOV 25 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
305 AM CST SUN NOV 25 2012
MAIN FORECAST CONCERNS ARE ON CLOUDS THROUGH THE PERIOD AND
TEMPERATURES.
07Z SURFACE ANALYSIS SHOWS TROUGH RUNNING FROM SOUTH CENTRAL
MINNESOTA...INTO NORTHWEST WISCONSIN. LARGE SHIELD OF STRATO-CUMULUS
SEEN BEHIND IT EXTENDING ALL THE WAY INTO THE DAKOTAS...MOVING
SOUTHEAST TOWARDS THE AREA. SNOW ACROSS CLARK AND TAYLOR COUNTIES
WAS EXITING EASTWARD.
25.00Z MODELS STRUGGLING WITH HANDING OF THE NEAR TERM
STRATO-CUMULUS DECK...WITH THE RAP DOING THE BEST.
OTHERWISE...MODELS IN GOOD AGREEMENT THROUGH THE REMAINDER OF THE
PERIOD.
IN THE NEAR TERM...25.03Z RAP RELATIVE HUMIDITY PROGS SHOW STRATUS
FIELD OVER MINNESOTA TO PUSH ACROSS THE FORECAST AREA TODAY IN THE
WAKE OF THE SURFACE TROUGH. 25.12Z NAM ON THE OTHER HAND SHOWS THIS
STRATUS OVER MAINLY THE NORTHERN SECTIONS. RAP VERIFYING BEST AT 07Z
AND THUS GOING FOR THE MORE PESSIMISTIC CLOUD FORECAST TODAY...WITH
MOSTLY CLOUDY SKIES. WITH THE CLOUDS AND 925MB-700MB COLD
ADVECTION...TEMPERATURES WILL NOT REBOUND MUCH FROM MORNING LOWS AND
THUS DID COOL TEMPERATURES A FEW DEGREES FROM THE PREVIOUS FORECAST
AND THIS INLINE WITH GUIDANCE TRENDS OF BEING COOLER.
HIGH PRESSURE BEGINS TO BUILD INTO THE NORTHERN PLAINS/MINNESOTA
TONIGHT. AS DRIER AIR ADVECTS INTO THE REGION DO EXPECT THE CLOUDS TO
BREAK UP SOMEWHAT...WITH SOME CLEARING LIKELY AS THE NIGHT WEARS
ON. SOME CONCERN THAT LOW LEVEL MOISTURE WILL GET TRAPPED UNDER
THE INVERSION AND THUS SEE VERY LITTLE CLEARING. ALSO CANNOT RULE
OUT A FEW FLURRIES THIS EVENING...BUT DID NOT INCLUDE IN THE GRIDS
AT THIS TIME. EXPECT TEMPERATURES TO DROP INTO THE TEENS...AND
PERHAPS A LITTLE COLDER IN AREAS WHERE SKIES WOULD CLEAR.
THE HIGH THEN SETTLES OVERHEAD MONDAY AND MONDAY NIGHT. WITH
850MB TEMPERATURES RANGING FROM -5 DEGREES ACROSS THE FAR SOUTH TO
-12 DEGREES IN THE NORTH...EXPECT THIS TO BE THE COLDEST DAY OF
THE WEEK...WITH HIGHS ONLY IN THE 20S.
THE HIGH WILL TRANSLATE TO THE SOUTHEAST ON TUESDAY...WITH WARM
ADVECTION ON ITS BACK SIDE AS WINDS COME AROUND TO THE SOUTHWEST.
WITH THE 850MB-700MB WARM ADVECTION...A BAND OF MID LEVEL CLOUDS ARE
EXPECTED TO TRAVERSE THE AREA. WITH 850MB TEMPERATURES IN THE -5 TO
-8 DEGREES CELSIUS RANGE...EXPECT HIGHS IN THE UPPER 20S TO MIDDLE
30S. A SHORTWAVE WILL TRANSLATE ACROSS LAKE SUPERIOR LATE IN THE
DAY...DRAGGING A WEAK SURFACE TROUGH THROUGH THE AREA. THIS WILL BE
NO MORE THAN A WIND SHIFT...WITH ANT PRECIPITATION REMAINING WELL TO
THE NORTH OF THE AREA NEAR THE MAIN WAVE. THE SOUTHWESTERLY WINDS
WILL KEEP TEMPERATURES FROM BOTTOMING OUT TUESDAY NIGHT...WITH LOWS
IN THE TEENS AND 20S.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
305 AM CST SUN NOV 25 2012
NORTHWESTERLY FLOW WITH HIGH PRESSURE AT THE SURFACE ON WEDNESDAY
WILL GIVE WAY TO A MORE ZONAL FLOW FROM THURSDAY THROUGH SATURDAY.
25.00Z GFS AND ECMWF DO DIFFER IN THEIR SOLUTIONS IN HANDLING THE
VARIOUS SHORTWAVES MOVING THROUGH THE FLOW. GFS DEPICTS A SHORTWAVE
IN THE FLOW OVER THE CENTRAL PLAINS ON THURSDAY...WHILE THE ECMWF IS
MUCH WEAKER AND FURTHER SOUTH OVER TEXAS. IN EITHER CASE...SOME
TRANSPORT OF LOW LEVEL MOISTURE MAY WORK ITS WAY NORTHWARD INTO
EASTERN IOWA AND SOUTHERN WISCONSIN THURSDAY NIGHT AND BRING A
SLIGHT CHANCE FOR SOME LIGHT PRECIPITATION TO THE AREA.
OTHERWISE...REMAINDER OF THE FORECAST PERIOD LOOKS DRY...WITH A
GRADUAL WARMING TREND INTO THE WEEKEND. IN FACT BOTH THE ECMWF AND
GFS ARE SHOWING 850MB TEMPERATURES RISING TO 8 TO 10 DEGREES
CELSIUS SATURDAY. THUS EXPECT TEMPERATURES TO WARM INTO THE MIDDLE
TO UPPER 40S AND PERHAPS 50 IN A FEW LOCATIONS.
&&
.AVIATION...THROUGH 06Z MONDAY
1108 PM CST SAT NOV 24 2012
THE SURFACE COLD FRONT HAS PUSHED ABOUT HALF AWAY ACROSS MINNESOTA
THIS EVENING. MID LEVEL CLOUDS ASSOCIATED WITH THE SHORT WAVE
TROUGH WILL BE EXITING THE REGION EARLY IN THE PERIOD ONLY TO BE
REPLACED BY LOWER CLOUDS. UPSTREAM OBSERVATIONS INITIALLY INDICATE
THE CEILINGS SHOULD LOWER TO AROUND 5K FEET AHEAD OF THE
FRONT...BUT THEN ONCE THE FRONT MOVES THROUGH...THESE SHOULD LOWER
TO MVFR. IR FOG PRODUCT SHOWS THIS MVFR DECK IS RATHER EXPANSIVE
COVERING MUCH OF NORTH DAKOTA BUT THE BACK EDGE SEEMS TO BE MOVING
ACROSS SOUTHERN SASKATCHEWAN. THE 25.03Z RAP HAS LOCKED ON TO
THIS MOISTURE AND BRINGS IT INTO THE AREA AND THEN TRAPS IT UNDER
THE LOW LEVEL INVERSION SUGGESTING THE CLOUDS WOULD LINGER THROUGH
MUCH OF SUNDAY. WILL INDICATE THESE CLOUDS COMING INTO BOTH TAF
SITES WITH THE FRONTAL PASSAGE BUT WITH A BACK EDGE VISIBLE ON
THE SATELLITE...WILL SHOW THEM SCATTERING OUT AROUND 18Z BASED ON
THE TIMING OF THE CURRENT MOVEMENT. IF THE CLOUDS DO NOT SCATTERED
OUT SUNDAY MORNING...WOULD THEN EXPECT THEM TO PERSIST INTO SUNDAY
NIGHT AS THE 25.00Z NAM DOES DISSIPATE THE LOW LEVEL INVERSION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
305 AM CST SUN NOV 25 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1108 PM CST SAT NOV 24 2012
.SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
300 PM CST SAT NOV 24 2012
MAIN FORECAST CONCERNS THIS PACKAGE...LIGHT SNOW CHANCES ACROSS THE
NORTH TONIGHT...CLOUD/TEMPERATURE TRENDS THRU THE PERIOD.
DATA ANALYSIS AT 18Z HAD A RIDGE OF HIGH PRESSURE FROM WESTERN ONT
THRU WI TO AR AND LOW PRESSURE FROM EASTERN CO TO LK WINNIPEG.
STRATO-CU CLOUDS CLEARING OVER WI/IL AS THE RIDGE AXIS MOVES EAST.
WINDS QUICKLY TURN SOUTH/SOUTHEAST ACROSS MN/IA WEST OF THE RIDGE
AXIS. 850-700MB WARM ADVECTION/ISENTROPIC LIFT AHEAD OF THE NEXT
TROUGH INTO THE NORTHERN PLAINS WAS ALREADY SPREADING MID LEVEL
MOISTURE/CLOUDS EASTWARD ACROSS MN/IA BEHIND THE RIDGE AXIS. EVEN
WITH SOME SUNSHINE AND SNOW-FREE GROUND ACROSS MOST OF THE FCST AREA
THIS MORNING...TEMPERATURES SLOW TO WARM WITH MID-DAY READINGS ONLY
IN THE MID 20S.
24.12Z MODELS INITIALIZED WELL AND OFFER VERY SIMILAR SOLUTIONS FOR
TONIGHT INTO TUE NIGHT AS WEAK SHORTWAVES IN NORTHWEST FLOW PASS
NEAR OR ACROSS THE UPPER MIDWEST. DPROG/DT OF 500MB HGTS AT 24.12Z
SHOWED THE MODEL RUNS OF 22.12Z AND 23.12Z VERIFIED QUITE WELL
ACROSS NOAM/EASTERN PAC. STRONGER OF EARLIER RUNS BETTER WITH
SHORTWAVE FEATURES OVER SASKAT AND SOUTHERN BC. LATEST RUNS
CONVERGED TOWARD A TIGHT CONSENSUS TONIGHT/SUN...FAVORING FASTER OF
EARLIER RUNS WITH FEATURES MOVING EAST NEAR THE US/CAN BORDER. TREND
IS TOWARD A COMPROMISE ON STRENGTH/TIMING OF THE NEXT SHORTWAVE
TROUGH INTO THE MID/UPPER MS VALLEY MON THEN INTO THE EASTERN U.S.
TUE. ECMWF WITH THE SOMEWHAT BETTER RUN-TO-RUN CONSISTENCY THIS
CYCLE. CHECK OF OBS VS. MODEL DATA AT 18Z SHOWED MODELS GENERALLY
GOOD WITH THE SFC MASS FIELDS OVER THE CENTRAL CONUS...BUT FOR GFS
ON THE DRY SIDE WITH SFC DEW POINTS NEAR/WEST OF THE SFC RIDGE AXIS.
PER WV IMAGERY MODELS LOOKED GOOD WITH THE SHORTWAVE DETAILS OVER
NOAM. A MODEL CONSENSUS LOOKED GOOD WITH THE 12-18Z PRECIP OVER THE
NORTHERN CONUS. GENERALLY FAVORED THE MODEL/ENSEMBLE CONSENSUS...
WEIGHTED A BIT TOWARD THE ECMWF WITH ITS BETTER RUN-TO-RUN
CONSISTENCY. SHORT-TERM FCST CONFIDENCE REMAINS GOOD THIS CYCLE.
FOR THE SHORT TERM...MAIN WEATHER OF CONCERN IN THE SHORT TERM IS
TONIGHT. STRONGEST OF THE 925-700MB WARM ADVECTION/ISENTROPIC LIFT
SPREAD ACROSS THE FCST AREA THIS EVENING...QUICKLY EXITING/WANING
AFTER MIDNIGHT. MAIN 500-300MB PV ADVECTION WITH THE SHORTWAVE
PASSES ACROSS THE NORTHEAST HALF OF WI THIS EVENING. DEEPEST OF THE
MOISTURE/SATURATION SPREAD ALSO SPREAD ACROSS DURING THE EVENING...
DIMINISHING QUICKLY AFTER MIDNIGHT WITH PASSAGE OF THE 850-700MB
TROUGH AXIS AND SHORTWAVE. MODEL SOUNDINGS INDICATE COLUMN REMAINS
COLD ENOUGH FOR PRECIP AS SNOW ACROSS THE NORTH HALF OF THE FCST
AREA...WHERE THE BETTER/DEEPER SATURATION OCCURS. LIFT/MOISTURE/
SATURATION GENERALLY ABOVE 850MB...BATTLING LOWER LEVEL DRY AIR IN
PLACE FROM THE RETREATING SFC RIDGE AXIS. GOOD MODEL CONSENSUS WITH
A STRONGER SHORTWAVE AND SOME DEEPER LIFT TO OVERCOME THE LOW LEVEL
DRY AIR OVER THE NORTH END OF THE FCST AREA...WITH SOME -SN ALONG/
NORTH OF HWY 29 BY LATER THIS EVENING. RAISED -SN CHANCES TO 60-70
PERCENT LATER THIS EVENING OVER TAYLOR/NORTHERN CLARK COUNTIES...
TAPERING TO NO PRECIP MENTION OVER THE SOUTHWEST 1/3 OF THE FCST
AREA. A QUICK HALF INCH OR SO OF SNOW POSSIBLE BETWEEN MAINLY 9PM-
MIDNIGHT ALONG/NORTH OF HWY 29. SOME CONCERN FOR -FZDZ AS THE PRECIP
ENDS...BUT APPEARS LOSS OF LIFT OCCURS AT THE SAME TIME AS THE
DECREASING DEPTH OF MOISTURE/LOSS OF ICE CRYSTALS IN THE CLOUDS AS
THE TROUGH AXIS PASSES. THUS LEFT ANY MENTION OF -FZDZ OUT OF GRIDS
FOR NOW. TEMPS TO REMAIN NEARLY STEADY THRU THE EVENING...THEN FALL
LATER TONIGHT WITH LOW LEVEL COLD ADVECTION AND DECREASE OF CLOUDS.
CLOUDS/SUNSHINE SOMEWHAT IN QUESTION FOR SUNDAY AS MODELS TRY TO
WRAP SOME 925-850MB MOISTURE SOUTHEAST INTO THE FCST AREA. THIS
MOISTURE IS THEN PUSHED EAST OF THE AREA FOR SUN NIGHT/MON AS SFC-
700MB RIDGING BUILDS INTO THE UPPER MIDWEST. GENERALLY LEFT SKIES
PARTLY CLOUDY THESE PERIODS GIVEN MODEL STRUGGLE WITH LOWER LEVEL
MOISTURE/RH THIS TIME OF YEAR. THE SFC-700MB RIDGE AXIS SLIDES
ACROSS THE REGION MON NIGHT...WITH WHAT SHOULD BE A DEEP...DRY
AIRMASS AND LIGHT WINDS. ANOTHER COLDER NIGHT MON NIGHT WITH THE
LIGHT WINDS AND CLEAR OR MOSTLY CLEAR SKIES. HGTS ALOFT FALL TUE
WITH APPROACH OF SOME MORE SHORTWAVE ENERGY CHANNELED IN THE
NORTHWEST FLOW. ANOTHER SFC-700MB FRONT/TROUGH APPROACHES ON TUE
WITH AN INCREASE OF MOISTURE/CLOUDS ABOVE 500MB. THIS ONE LOOKS
TO HAVE WEAKER FORCING/LIFT AND LESS MOISTURE THAN THE ONE PASSING
TONIGHT...AND LEFT TUE/TUE NIGHT DRY.
GENERALLY FAVORED A BLEND OF THE NUMERICAL GUIDANCE LOWS/HIGHS FOR
TONIGHT THRU TUE NIGHT GIVEN CONCERNS WITH CLOUD COVER AND LARGE
IMPACT CLOUDS...OR NOT...CAN HAVE ON HIGHS/LOWS THIS TIME OF YEAR.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
300 PM CST SAT NOV 24 2012
MEDIUM RANGE MODEL RUNS OF 24.00Z/24.12Z IN GOOD AGREEMENT ON WED
WITH A BROAD NORTHWEST FLOW ALOFT ACROSS THE UPPER MIDWEST. GFS/
ECMWF OFFER RATHER GOOD RUN-TO-RUN CONSISTENCY WED. AGREEMENT OF
24.00/12Z MODELS REMAINS RATHER GOOD THU/FRI WITH SLOW EASTWARD
PROGRESS AND FLATTENING OF THE WESTERN NOAM RIDGING AS SOME
SHORTWAVE ENERGY MOVES THRU THE FLOW. CONSENSUS GOOD WITH A WEAK
SHORTWAVE TO PASS ACROSS THE MID/UPPER MS VALLEY THU NIGHT...THEN
DIFFER WITH THE SHORTWAVE TIMING/STRENGTH DETAILS BY FRI/SAT. RUN-
TO-RUN CONSISTENCY REMAINS GOOD THU THEN BEGINS TO DEGRADE BY
FRI/SAT. TREND BY SAT IS SLOWER THAN THE 23.00/12Z RUNS WITH THE
NEXT LONGWAVE TROUGH APPROACHING THE WEST COAST...WITH MORE RIDGING
ALOFT TO BE OVER CENTRAL NOAM NEXT WEEKEND. LONG TERM FCST
CONFIDENCE GOOD WED/THU THEN AVERAGE FRI/SAT.
DAYS 4-7 CONTINUE TO LOOK LIKE A RATHER QUIET PERIOD ACROSS THE
REGION WITH SLOWLY RISING HGTS AND RIDGING ALOFT BUILDING OVER
CENTRAL NOAM. CAN HIGH PRESSURE DRIFTS SOUTHEAST OVER THE AREA WED.
A WEAK BUT MOISTURE-STARVED SFC-LOWER LEVEL TROUGH LOOKS TO SLIDE
ACROSS THE AREA THU. DEPENDING ON MODEL...WITH GFS THE STRONGEST...
A SHORTWAVE TO MOVE ACROSS THE REGION THU NIGHT INTO FRI. MAY YET
NEED A SMALL -SN/-RA CHANCE THU NIGHT INTO FRI BUT LEFT THIS DRY FOR
NOW AS GFS LOOKS OVERDONE WITH ITS TROUGH AND SFC LOW...PLUS PLENTY
OF DETAIL DIFFERENCES BY FRI. BETTER CONSENSUS FOR SOUTHERLY FLOW
AND STRONGER LOW LEVEL WARM ADVECTION TO SPREAD ACROSS THE UPPER
MIDWEST SAT. MODELS SHOWING A RATHER RAPID NORTHWARD SPREAD OF GULF
OF MEX MOISTURE. MODELS SEEM TOO FAST WITH THIS AND PER THE MODEL/
ENSEMBLE CONSENSUS WILL LEAVE SAT DRY FOR NOW. STUCK WITH THE
MODEL/ENSEMBLE CONSENSUS OF GRADUALLY WARMING TEMPERATURES IN THE
WED-SAT PERIOD AS WELL.
&&
.AVIATION...THROUGH 06Z MONDAY
1108 PM CST SAT NOV 24 2012
THE SURFACE COLD FRONT HAS PUSHED ABOUT HALF AWAY ACROSS MINNESOTA
THIS EVENING. MID LEVEL CLOUDS ASSOCIATED WITH THE SHORT WAVE
TROUGH WILL BE EXITING THE REGION EARLY IN THE PERIOD ONLY TO BE
REPLACED BY LOWER CLOUDS. UPSTREAM OBSERVATIONS INITIALLY INDICATE
THE CEILINGS SHOULD LOWER TO AROUND 5K FEET AHEAD OF THE
FRONT...BUT THEN ONCE THE FRONT MOVES THROUGH...THESE SHOULD LOWER
TO MVFR. IR FOG PRODUCT SHOWS THIS MVFR DECK IS RATHER EXPANSIVE
COVERING MUCH OF NORTH DAKOTA BUT THE BACK EDGE SEEMS TO BE MOVING
ACROSS SOUTHERN SASKATCHEWAN. THE 25.03Z RAP HAS LOCKED ON TO
THIS MOISTURE AND BRINGS IT INTO THE AREA AND THEN TRAPS IT UNDER
THE LOW LEVEL INVERSION SUGGESTING THE CLOUDS WOULD LINGER THROUGH
MUCH OF SUNDAY. WILL INDICATE THESE CLOUDS COMING INTO BOTH TAF
SITES WITH THE FRONTAL PASSAGE BUT WITH A BACK EDGE VISIBLE ON
THE SATELLITE...WILL SHOW THEM SCATTERING OUT AROUND 18Z BASED ON
THE TIMING OF THE CURRENT MOVEMENT. IF THE CLOUDS DO NOT SCATTERED
OUT SUNDAY MORNING...WOULD THEN EXPECT THEM TO PERSIST INTO SUNDAY
NIGHT AS THE 25.00Z NAM DOES DISSIPATE THE LOW LEVEL INVERSION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
300 PM CST SAT NOV 24 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...04
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
146 AM MST TUE NOV 27 2012
.AVIATION...
UPDATED KDEN AND KAPA TAFS AS IT LOOKS LIKE WINDS WILL HAVE A
MORE WESTERLY COMPONENT STRETCHING OUT OF THE FOOTHILLS OVER
KDEN...WITH LIGHTER WINDS OVER KAPA. NO CHANGE TO KBJC. VFR
CONDITIONS EXPECTED THROUGH TONIGHT. POTENTIAL STILL EXISTS FOR
MOUNTAIN WAVE CLOUD DEVELOPING ALONG FOOTHILLS BETWEEN 11Z AND 15Z
AS AN AREA OF MOISTURE ALOFT CURRENTLY OVER WYOMING MOVES
SOUTHEAST. GUSTS UP TO 20 KTS POSSIBLE AT BJC.
&&
.PREV DISCUSSION... /ISSUED 838 PM MST MON NOV 26 2012/
UPDATE...HAVE UPDATED TO ADJUST MINS OVERNIGHT AS WE HAVE ALREADY
DROPPED AT OR BLO OUR FORECAST MINS IN A COUPLE OF AREAS. COLDEST
READINGS MAY OCCUR PRIOR TO 2 AM WITH SOME MODIFICATION
THEREAFTER ONCE DRAINAGE WINDS KICK IN. MOUNTAIN WAVE OVERNIGHT
MAY ALSO MODIFY THE LOWS OVERNIGHT IN AND NEAR THE FOOTHILLS. A
COUPLE OF POCKETS OF STRATUS STILL OVER EASTERN LARIMER AND
NORTHWEST WELD...AS WELL AS OVER SEDGWICK AND PHILLIPS COUNTIES
THIS EVENING. LOW CLOUDS WILL DIMINISH IN THOSE AREAS AS WELL OVER
THE NEXT FEW HOURS.
AVIATION...VFR CONDITIONS OVERNIGHT. NO SIGNIFICANT CHANGES IN
THE UPCOMING TAFS WITH DRAINAGE WINDS AT KDEN AND KAPA. SOME
MOUNTAIN WAVE ACTIVITY COULD KICK UP THE WINDS NEAR KBJC TOWARDS
12Z...MORE THAN IN THE CURRENT TAF SO SOME ADJUSTMENT MAY BE
NECESSARY AROUND THAT TIME.
PREV DISCUSSION... /ISSUED 313 PM MST MON NOV 26 2012/
SHORT TERM...WEAK SURFACE HIGH SLIDING ACROSS CENTRAL PLAINS
BEHIND THIS MORNING`S COLD FRONT. LOW CLOUDS ACROSS PLAINS STILL
FAIRLY EXTENSIVE BUT BEGINNING TO DISSIPATE EAST OF DENVER. STILL
SOME FOG PERSISTING IN THE FOOTHILLS WEST OF DENVER...ALSO SHOWING
SIGNS OF DISSIPATING. LATEST RUC CONTINUES TO SHOW A SLOW
DISSIPATION OF THE LOW CLOUDS DURING THE EVENING WITH MAINLY CLEAR
SKIES BY MIDNIGHT. THIS LOOKING REASONABLE AS DRIER AIR MOVES INTO
REGION FROM THE WEST. THERE WILL BE SOME INCREASE IN HIGH LEVEL
MOISTURE OVERNIGHT WITH WRF SYNTHETIC SATELLITE IMAGERY SUGGESTING
THE DEVELOPMENT OF A WAVE CLOUD TOWARDS MORNING. WINDS TO INCREASE
AGAIN ACROSS MOUNTAINS AND HIGHER FOOTHILLS AFTER MIDNIGHT AS
NORTHWEST FLOW ALOFT INCREASES. MODELS SHOW CROSS MOUNTAIN FLOW
AROUND 40 KTS AT MOUNTAIN TOP AT MIDNIGHT. SOME GUSTS AROUND 50
MPH POSSIBLE OVERNIGHT ACROSS THE WIND PRONE AREAS AND EXPOSED
SLOPES. OVERNIGHT TEMPERATURES TO BE WARMER NEAR THE FOOTHILLS
WITH COLDER TEMPERATURES IN LOW LYING AREAS OF THE PLAINS. ON
TUESDAY...MODERATE WEST NORTHWEST ALOFT TO PREVAIL AS UPPER RIDGE
BUILDS INTO AREA. GUSTY WINDS WILL CONTINUE ACROSS THE MOUNTAINS
AND FOOTHILLS...EXTENDING INTO THE WESTERN SECTIONS OF THE URBAN
CORRIDOR DURING THE MORNING. SOME GUSTS TO 50 MPH WILL BE POSSIBLE
OVER THE HIGHER EXPOSED AREAS. BY 18Z GRADIENT ACROSS THE PLAINS
AND LOWER FOOTHILLS EXPECTED TO WEAKEN...THUS SHOULD SEE WINDS
DECREASE AS A RESULT. HOWEVER...BREEZY CONDITIONS WILL PERSIST
ACROSS THE MOUNTAINS AND HIGHER FOOTHILLS. MODELS HINT AT WAVE
CLOUD ALONG FOOTHILLS DECREASING DURING THE MORNING...WITH MAINLY
CLEAR SKIES PREVAILING BY AFTERNOON ACROSS THE REGION. AIRMASS
ACROSS PLAINS TO BE MUCH WARMER THAN TODAY WITH HIGHS WARMING INTO
THE MID 50S TO MID 60S. ALSO A SLIGHT WARMUP EXPECTED FOR
MOUNTAINS WITH HIGHS IN THE 40S.
LONG TERM...MODELS HAVE AN UPPER RIDGE MOVING INTO AND OVER THE
FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY. FOR THE MOST PART
.ZONAL FLOW WILL COVER THE CWA INTO THURSDAY MORNING. A WEAK
UPPER TROUGH IS PROGGED TO MOVE THROUGH LATER THURSDAY MORNING
.WITH INCREASING NORTHWESTERLY FLOW ALOFT THE REST OF THURSDAY
AND THURSDAY NIGHT. THE QG VERTICAL VELOCITY FIELDS SHOW BENIGN
SYNOPTIC SCALE ENERGY OVER THE CWA TUESDAY NIGHT THROUGH THURSDAY
NIGHT. NORMAL DIURNAL WIND PATTERNS ARE EXPECTED TUESDAY NIGHT
.WITH DOWNSLOPE WEDNESDAY AND WEDNESDAY NIGHT. A FAIRLY WEAK
GRADIENT IS PROGGED THURSDAY AND THURSDAY NIGHT...SO NORMAL
PATTERNS ARE LIKELY. FOR MOISTURE...THERE IS VERY LITTLE TUESDAY
NIGHT AND WEDNESDAY. BY WEDNESDAY NIGHT SOME MID AN UPPER LEVEL
MOISTURE IS PROGGED TO MOVE IN. THE NAM HAS SOME FAIRLY DEEP
MOISTURE OVER THE MOUNTAINS THURSDAY MORNING AT 12Z...THE GFS HAS
LESS...THE ECMWF WAY LESS. FOR THE REST OF THURSDAY AND THURSDAY
NIGHT...THERE IS A BIT OF UPPER LEVEL MOISTURE PROGGED. THE QPF
FIELDS HAVE NO MEASURABLE PRECIPITATION NOTED THROUGH THE FIVE
PERIODS...WITH THE EXCEPTION OF A TINY BIT OVER THE FAR NORTHWEST
CWA THURSDAY MORNING AT 12Z ON THE NAM. WILL LEAVE POPS OUT FOR
ALL AREAS FOR NOW. FOR TEMPERATURES...WEDENSDAY`S HIGHS LOOK 1-2 C
WARMER THAN TUESDAY`S. THURSDAY`S HIGHS ARE 0-2 C COOLER THAN
WEDNESDAY`S. FOR THE LATER DAYS...FRIDAY THROUGH MONDAY...MODELS
HAVE WEST-SOUTHWESTERLY FLOW ALOFT...WITH VERY LIMITED MOISTURE.
TEMPERATURES LOOK TO STAY ABOVE SEASONAL NORMALS.
AVIATION...LOW CLOUDS SLOWLY ERODING ACROSS AREA...WITH MVFR
CEILINGS PERSISTING AT BJC AND APA. CLOUDS TO CONTINUE TO ERODE
THROUGH THE EVENING WITH IMPROVING CEILINGS. SHOULD EXPECT VFR
CONDITIONS AT BJC AND APA BY 02Z. VFR CEILINGS TO PREVAIL AT DEN
WITH CEILINGS AROUND 7000 FEET AGL BY 02Z. SKIES TO CLEAR ACROSS
THE AREA AROUND 06Z WITH A GRADUAL INCREASE IN HIGH LEVEL MOISTURE
OVERNIGHT. POTENTIAL FOR MOUNTAIN WAVE CLOUD DEVELOPING ALONG
FOOTHILLS BETWEEN 08Z AND 15Z...SHOULD NOT HAVE MUCH IMPACT ON
AREA AIRPORTS. LIGHT SOUTHEASTERLY WINDS THIS EVENING WITH
DRAINAGE FLOW DEVELOPING BY MIDNIGHT. SPEEDS AROUND 10 KTS
EXPECTED OVERNIGHT...THOUGH GUSTS UP TO 20 KTS POSSIBLE AT BJC.
WINDS TO DECREASE AND BECOME NORTHWEST ACROSS THE AREA BY 18Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....RJK
AVIATION...KRIEDERMAN
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
303 AM EST TUE NOV 27 2012
.SHORT TERM /TODAY THROUGH THURSDAY/...
HIGH PRESSURE WHICH HAS PROVIDED FAIR WEATHER ACROSS THE REGION OVER
THE LAST FEW DAYS WILL MOVE EAST THIS MORNING...ALLOWING MOISTURE
AHEAD OF AN APPROACHING COLD FRONT TO WORK ITS WAY INTO WESTERN AND
NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON. CURRENT RADAR
IMAGERY WEST OF THE REGION DOES NOT INDICATE MUCH IN THE WAY OF
PRECIPITATION...BUT THIS COVERAGE IS EXPECTED TO INCREASE AS AN
UPPER TROUGH PIVOTS INTO THE SOUTHEAST AND STRENGTHENS THE SYSTEM TO
THE NORTHWEST. AS MUCH OF THE ENERGY AHEAD OF THE FRONT SHIFTS TO
THE NORTHEAST WITH THE SURFACE LOW...NOT EXPECTING MUCH
PRECIPITATION COVERAGE INTO NORTHEAST FLORIDA. THE BEST CHANCE FOR
RAINFALL ACROSS THE CWA WILL BE IN SOUTHEAST GEORGIA FROM NOON TO
MIDNIGHT TODAY.
THE SURFACE FRONT WILL CLEAR TO THE SOUTH OVERNIGHT TONIGHT...WITH
HIGH PRESSURE BUILDING IN BEHIND. THIS HIGH WILL BE JUST NORTH OF
THE REGION WEDNESDAY AND...THEN SHIFT OFF THE EAST COAST THURSDAY.
THIS WILL SET UP AN ONSHORE FLOW THURSDAY AFTERNOON...BUT BEST
MOISTURE FOR RAINFALL SHOULD STAY OFFSHORE INITIALLY.
HAVE FAVORED GFS MOS NUMBERS THIS PERIOD. READINGS NEAR
CLIMATOLOGICAL NORMS ARE EXPECTED DESPITE THE PASSING OF THE COLD
FRONT...AS THE AIRMASS BEHIND IT IS NOT THAT COLD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
WITH SURFACE HIGH PRESSURE REMAINING OVER THE CAROLINAS ONSHORE FLOW
WILL CONTINUE THURSDAY NIGHT THROUGH SUNDAY. WHILE MAINLY COASTAL
SHOWERS ARE EXPECTED...THERE COULD BE A FEW PERIODS WHERE STRONGER
RIBBONS OF MOISTURE COULD PUSH RAIN FURTHER INLAND. THE SURFACE HIGH
IS PROGGED TO SLIP A LITTLE TO THE SOUTH ON MONDAY...WHICH WOULD
PUSH THE COASTAL SHOWERS SOUTH OF THE FORECAST AREA. HAVE FAVORED
GFS MOS GUIDANCE THIS PERIOD...WITH ABOVE NORMAL TEMPERATURES
EXPECTED.
&&
.AVIATION...TEMPO MVFR POSSIBLE AT JAX...CRG...VQQ AND GNV EARLY
THIS MORNING WITHIN A COUPLE HOURS OF SUNRISE. THE ONLINE RAP MODELS
AND SHORT TERM GUIDANCE SUGGEST THAT LOWERING CIGS MAY ROTATE NNE
FROM CENTRAL FL EARLY THIS MORNING...WITH THE RAP AS LOW AS LIFR
CONDITIONS. DID NOT NOT ANY OF THESE LOWER CIGS TO OUR SOUTH EARLY
THIS MORNING...BUT DID INCLUDE TEMPO 2.5-3 KFT AT GNV AND DUVAL
COUNTY TERMINALS. HIGH AND MID CLOUDS WILL BLANKET THE AREA TODAY IN
ADVANCE OF THE FRONT...AND INCLUDED VCSH AT SSI THIS EVENING.
&&
.MARINE...SEPARATED THE COASTAL WATERS FORECAST BETWEEN NEAR AND
OFFSHORE. WINDS AND SEAS WILL BUILD OVER THE OFFSHORE WATERS LATE
TONIGHT INTO WED FOLLOWING THE FRONTAL PASSAGE...WITH SCEC
CONDITIONS POSSIBLE OVER THE OFFSHORE WATERS. WINDS WILL GRADUALLY
RELAX INTO THE WEEKEND AS HIGH PRESSURE BUILD NNE OF THE REGION.
PERSISTENT ONSHORE FLOW IS EXPECTED WITH AN INCREASE IN EASTERLY
SWELLS.
RIP CURRENTS: LOW RISK TODAY DUE TO OFFSHORE FLOW FLOW AND LOWER
WAVE HEIGHTS. MODERATE RISK EXPECTED ON WEDNESDAY DUE TO INCREASING
NNE FLOW. THE RIP CURRENT RISK IS EXPECTED TO REMAIN ELEVATED
THROUGH THE WEEKEND DUE TO PERSISTENT ONSHORE FLOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 64 43 68 41 / 60 50 10 0
SSI 67 51 65 51 / 30 30 10 10
JAX 70 50 67 49 / 20 20 10 10
SGJ 72 53 69 53 / 10 20 10 10
GNV 73 47 72 45 / 10 20 10 0
OCF 76 50 74 48 / 10 20 10 0
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
STRUBLE/ENYEDI
AREA FORECAST DISCUSSION
NWS JACKSON KY
245 AM EST TUE NOV 27 2012
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
COLD FRONT CONTINUES TO MARCH SOUTHWARD ACROSS NORTHERN AND CENTRAL
KENTUCKY THIS MORNING. PRECIPITATION IS ALREADY STARTING TO END FROM
WEST TO EAST AND WILL CONTINUE TO END THROUGH DAYBREAK...HOLDING ON
ACROSS THE FAR EAST AND SOUTHEAST UNTIL ABOUT 13Z. HRRR SEEMS IN
PRETTY GOOD AGREEMENT WITH CURRENT PRECIPITATION TRENDS AND HAS A
VERY GOOD HANDLE ON ENDING OF PRECIPITATION THIS MORNING. AS IT
STANDS NOW...IT APPEARS PRECIPITATION SHOULD PULL OUT OF THE AREA
PRIOR TO A CHANGEOVER TO SNOW. THE ONLY EXCEPTION TO THIS MAY BE NEAR
THE VIRGINIA BORDER AND ONLY IN ELEVATIONS ABOVE 2000 FEET.
REGARDLESS...WITH ONLY LIGHT PRECIPITATION TOTALS ANTICIPATED AND
WARM SURFACE TEMPERATURES (ABOVE FREEZING)...NOT ANTICIPATING ANY
SNOWFALL ACCUMULATIONS. WE HAVE SEEN A CHANGEOVER TO SNOW AT
CVG...BUT THIS CHANGEOVER TO THE SOUTH WILL NOT PROGRESS FAST
ENOUGH. TEMPERATURES WILL STILL COOL INTO THE LOWER 30S IN THE NORTH
PRIOR TO DAYBREAK...SO STILL GOING TO BE PLENTY COOL. GIVEN THE COLD
ADVECTION TODAY...AND POSSIBLE LINGERING CLOUD COVER...HAVE WENT
BELOW GUIDANCE FOR HIGHS TODAY...GENERALLY AROUND 40 FOR MOST AREAS.
SKIES WILL CLEAR THIS AFTERNOON AND EVENING...WITH A COLD NIGHT
EXPECTED TONIGHT. A FAST MOVING WAVE IS EXPECTED TO PUSH ACROSS THE
NORTHERN OHIO RIVER VALLEY...BUT CLOUD COVER FROM THIS SYSTEM WILL
REMAIN NORTH OF KENTUCKY. THUS...WE SHOULD DECOUPLE NICELY TONIGHT IN
THE VALLEYS WITH TEMPERATURES FALLING WELL INTO THE 20S. CONTINUED TO
GO BELOW GUIDANCE FOR HIGHS ON WEDNESDAY GIVEN VERY LITTLE
IMPROVEMENT IN THE COOL AIRMASS OVER THE AREA. MODELS MAY BE TOO
AGGRESSIVE ON BRINGING THE WARMER WEATHER BACK INTO EASTERN KENTUCKY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
SURFACE HIGH PRESSURE OVER EASTERN KY AND A 50 H TROF OVER NEW
ENGLAND WITH RIDGING BUILDING INTO THE MIDWEST WILL BEGIN THE
EXTENDED FORECAST WITH COOL BUT FAIR WEATHER. HIGH TEMPS WILL SLOWLY
CLIMB INTO THE LOWER 50S AFTER A COLD NIGHT GENERALLY IN THE UPPER
20S. BY THURSDAY NIGHT THE SURFACE HIGH WILL BE LOCATED OFF THE
CAROLINA COAST WITH SOUTHERLY WINDS AND TEMPERATURES ONLY FALLING
INTO THE LOWER 30S. THEN ON FRIDAY A 50H DISTURBANCE WILL SWEEP THRU
THE OHIO VALLEY AND BRING A LOW CHANCE FOR RAIN TO EASTERN KY.
RAINFALL SHOULD BE LIGHT AND WITH CONTINUED SOUTHERLY WINDS AT THE
SFC TEMPERATURES RISE INTO THE MID AND UPPER 50S. CLOUDS AND A FEW
VERY LIGHT SHOWERS WILL LINGER INTO SAT WITH TEMPS ONLY FALLING INTO
THE LOWER 40S SAT MORNING BEFORE CLIMBING INTO THE UPPER 50S. ANOTHER
FAST MOVING SHORT WAVE WILL SWEEP THRU THE OHIO VALLEY ON SUN WITH
EARLY MORNING TEMPS IN THE UPPER 40S AND DAYTIME HIGHS IN THE LOWER
60S. THE RAIN MAY LINGER THRU SUN NIGHT BUT THE UPPER WEATHER PATTERN
WILL BEGIN TO SHIFT FROM A FAST ZONAL FLOW TO A MORE AMPLIFIED
PATTERN WITH 50H RIDGING BUILDING INTO THE MISS RIVER VALLEY. THAT
KEEPS NORTHWEST FLOW OVER THE AREA FOR SUNDAY NIGHT WITH CONTINUES
LIGHT RAIN POSSIBLE AS TEMPERATURES MONDAY MORNING ONLY FALL INTO THE
UPPER 40S WITH CONTINUED SW FLOW. LOOK FOR SOME CLEARING ON MONDAY AS
THE 50H RIDGE BUILDS INTO THE OHIO VALLEY AND TEMPERATURES SOAR INTO
THE MID 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1229 AM EST TUE NOV 27 2012
COLD FRONT WILL MARCH SOUTHWARD ACROSS EASTERN KENTUCKY OVERNIGHT
INTO TUESDAY MORNING. CIGS WILL QUICKLY COME DOWN OVER THE NEXT 2 TO
3 HOURS WITH CIGS SOLIDLY AROUND 800 FEET OR LOWER BY 09Z. WITH SOME
HEAVIER PRECIPITATION...A SLIGHT REDUCTION IN VISIBILITY CAN BE
EXPECTED THROUGH ABOUT DAYBREAK. THE THREAT FOR SNOW WILL REMAIN AT
OR ABOVE 2000 FEET ON THE RIDGES NEAR THE VIRGINIA BORDER.
HOWEVER...VERY LITTLE IF ANY ACCUMULATION IS EXPECTED. THE CIGS WILL
IMPROVE AND CLEAR BY EARLY TO MID AFTERNOON...ALTHOUGH MUCH OF THE
MORNING WILL REMAIN WITH LOW CIGS. THE VFR CONDITIONS WILL LINGER
THROUGH TUESDAY NIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KAS
LONG TERM....DUSTY
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1220 AM EST TUE NOV 27 2012
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 421 PM EST MON NOV 26 2012
MAIN ITEM OF CONCERN FOR THE START OF THE SHORT TERM WILL BE THE
ONGOING LES...MAINLY OVER THE EASTERN CWA.
HIGH PRESSURE RIDGE MOVING OVER THE CWA FROM HIGH OVER THE LOWER
GREAT LAKES AND AHEAD OF A LOW APPROACHING FROM NEAR LAKE WINNIPEG
WILL ALLOW THE WINDS TO BACK TO THE WEST THIS EVENING AND THEN
WEST-SOUTHWEST DURING THE OVERNIGHT HOURS. THIS...COMBINED WITH
LOWERING INVERSION HEIGHTS THIS EVENING WILL CONTINUE TO DIMINISH
LES INTENSITY THROUGH THE EVENING OVER THE WEST. THINK THE AREA THAT
WILL HANG ONTO IT THE LONGEST WILL BE OVER NORTHERN HOUGHTON
COUNTY...UNDER INCREASED CONVERGENCE WITH THE BACKING WINDS. AS THE
WINDS CONTINUE TO BACK TO THE SOUTH WEST...HIGH RES MODELS
INDICATING A STRONGER BAND OF LAKE EFFECT SNOW BECOMING PARALLEL TO
OR RIGHT OVER THE WESTERN KEWEENAW SHORELINE FROM THE UPPER
ENTRANCE TO EAGLE HARBOR. WITH THE LOWER INVERSION AND
DRIER AIR ALOFT INITIALLY...DON/T THINK THE INTENSITY WILL BE TOO
STRONG...BUT COULD SEE A BRIEF INCREASE LATE TONIGHT AS DEEPER
MOISTURE ARRIVES AHEAD OF THE APPROACHING LOW/FRONT. IF THE
SOUTHWEST FLOW WASN/T PRODUCING AS MUCH WAA...H850 TEMPS RISING TO
-9C BY 12Z TUESDAY AND LOWERING LOW LEVEL LAPSE RATES...WOULD BE
CONCERNED ABOUT HIGHER SNOW AMOUNTS. LAKE EFFECT SNOW
PARAMETER ALSO SHOWING THIS QUICK UPTICK IN ACTIVITY LATE
TONIGHT AND THEN QUICKLY DIMINISHING TOWARDS DAYBREAK
WITH THE WAA.
AS FOR THE EAST...EXPECT NORTHWEST WIND LES...AIDED BY THE
CONVERGENCE OVER THE EASTERN LAKE FROM A SURFACE TROUGH...TO
CONTINUE OVER THE NEXT SEVERAL HOURS IN THE MUNISING TO GRAND MARAIS
AREA. MODELS SEEM TO BE STRUGGLING WITH THE STRENGTH OF THE
TROUGH...BUT THE RAP HAS HAD A DECENT HANDLE ON IT THROUGH THE
DAY...DUE TO BETTER INITIALIZATION OF LOW LEVEL WINDS...AND WILL
FOLLOW THAT FOR THE NEAR TERM. RADAR ESTIMATES OF 1-2 IN/HR
SNOW IN THAT AREA OVER THE LAST COUPLE OF HOURS AND WILL KEEP THE
LES WARNING GOING THROUGH 03Z TONIGHT. AFTER 03Z...H950-900 WINDS
BACK TO THE WEST-NORTHWEST AND START PUSH THE STRONGER BAND OFF TO
THE EAST. THIS SHOULD ACCELERATE THROUGH THE OVERNIGHT HOURS...AS
WINDS BECOME WESTERLY AND THEN WEST-SOUTHWEST LATE. STILL EXPECT
THERE TO BE SOME HEAVIER SNOW IN THIS BAND...BUT THE TRANSIENT
NATURE WILL KEEP ACCUMULATIONS LIMITED AFTER 03Z. COULD NEED A BRIEF
ADVISORY ON THE BACK SIDE OF THE WARNING FOR ALGER AND NORTHERN
SCHOOLCRAFT...BUT WITH IT QUICKLY WINDING DOWN AND SPS THIS EVENING
SHOULD COVER IT. WITH THE SNOW AMOUNTS SHOWN ON RADAR...HAVE BUMPED
UP SNOW AMOUNTS THROUGH 3Z...WITH 5-7IN BETWEEN MUNISING AND
SHINGLETON.
WEAK LOW PRESSURE SYSTEM CURRENTLY TO THE WEST OF LAKE WINNIPEG AND
ASSOCIATED COLD FRONT WILL SWEEP ACROSS WESTERN LAKE SUPERIOR LATE
TUESDAY MORNING THROUGH TUESDAY EVENING. WITH THE SOUTHWEST FLOW
IN PLACE ON TUESDAY MORNING...EXPECT THE MAIN SNOW TO BE OCCURRING
OVER WESTERN/NORTHERN LAKE SUPERIOR AND POTENTIALLY RIGHT ALONG THE
NORTHWEST SHORELINE OF KEWEENAW COUNTY. LOW-MID CLOUDS SHOULD BE
PUSHING INTO THE AREA AHEAD OF THIS SYSTEM ON TUESDAY MORNING...SO
EXPECT MUCH OF THE AREA TO BE CLOUDY...ALTHOUGH THERE COULD BE SOME
BREAKS OVER THE EAST DEPENDING ON HOW THICK THE 6-10KFT DECK IS.
WITH DECENT H850 WAA MOVING THROUGH COULD ALSO SEE SOME
ISOLATED/SCATTERED SNOW SHOWERS MOVING OVER THE WESTERN LAKE AND
FAR WESTERN UPPER MI DURING THE MORNING. THEN...WITH THE ARRIVAL OF
THE WEAK SHORTWAVE...ASSOCIATED HEIGHT FALLS...AND H850-500 Q-VECTOR
CONV AND WAA OVER THE WESTERN HALF OF THE CWA IN THE
AFTERNOON...THINK THERE WILL BE ENOUGH TO PRODUCE SCATTERED SNOW
SHOWERS OVER THE WESTERN/CENTRAL CWA DURING THE AFTERNOON. THE
STRONGEST SNOW SHOWERS WILL LIKELY BE OVER THE KEWEENAW
PENINSULA...WHERE WINDS WILL VEER DURING THE AFTERNOON AND PUSH ANY
LES BAND OVER THE WESTERN LAKE ONSHORE.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 421 PM EST MON NOV 26 2012
TUESDAY NIGHT...THE MODELS WERE IN REASONABLE AGREEMENT WITH THE
CLIPPER SHORTWAVE TROUGH INTO WRN UPPER MI AT 00Z/WED. AS THE SHRTWV
AND ASSOCIATED COLD FRONT MOVES THROUGH...WINDS WILL VEER FROM SW TO
NW. WITH FAVORABLE 850-700 MB MOISTURE...850 MB TEMPS AROUND
-11C...AND LOW LEVEL CONVERGENCE NEAR THE FRONT ..EXPECT A PERIOD OF
MODERATE TO HEAVY LAKE EFFECT SNOW TO MOVE THROUGH THE WEST IN THE
EVENING AND THEN FOCUS MAINLY OVER THE NE CWA LATE WED NIGHT.
SNOWFALL AMOUNTS MAY APPROACH ADVY CRITERIA OF AROUND 4 INCHES...IN
HIGHER TERRAIN OVER THE WEST SOUTH OF HOUGHTON AND OVER EASTERN
ALGER INTO NRN LUCE COUNTIES.
WEDNESDAY...THE LES SHOULD DIMINISH FROM WEST TO EAST AS A SFC RIDGE
BUILDS INTO THE AREA WITH BACKING WINDS AND DROPPING INVERSION
HEIGHTS. THE BEST CHANCE FOR SIGNIFICANT ACCUMULATIONS WILL REMAIN
OVER THE FAR NE CWA IN THE MORNING (NE LUCE COUNTY) WHERE THE HIGHER
RES MODELS INDICATE POTENTIAL FOR GREATEST LOW LEVEL CONV WITH
300-310 FLOW.
WED NIGHT INTO THU...AS A SHRTWV MOVES THROUGH NRN ONTARIO AND HIGH
PRES BUILDS FROM NRN ALBERTA AND SASK INTO NRN ONTARIO...ANOTHER
WEAK COLD FRONT WILL DROP THROUGH THE NRN GREAT LAKES. BEHIND THE
FRONT...WINDS ARE EXPECTED TO VEER TO THE NORTHEAST. WITH ONLY
SHALLOW COLD AIR MASS AND DRY ACYC FLOW INTO THE AREA...ONLY SLIGHT
CHANCE POPS WERE INCLUDED FOR -SHSN LATE WED NIGHT INTO THU MORNING
OVER MAINLY N CNTRL UPPER MI.
FRIDAY THROUGH MONDAY...THE MODELS WERE IN GENERAL AGREEMENT WITH A
TRANSITION TO A MORE ZONAL PATTERN BRINGING MILD PACIFIC AIR INTO
THE REGION. AS WAA AND MOISTURE ADVECTION INCREASES FRIDAY...ENOUGH
COLD AIR IS EXPECTED TO LINGER SO THAT MAINLY -SN WOULD BE EXPECTED
WITH ANY LIGHT PCPN. THE ECMWF WAS STRONGER/SLOWER WITH A SHORTWAVE
RESULTING IN A MORE PRONOUNCED WARM/MOIST SURGE SATURDAY COMPARED TO
THE GFS/GEM. FOLLOWING THE RAIN CHANCES SAT...MOIST/MILD AIR IS
EXPECTED TO LINGER INTO EARLY NEXT WEEK WHEN ADDITIONAL RAIN CHANCES
ARE POSSIBLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1219 AM EST TUE NOV 27 2012
LAKE EFFECT -SHSN WILL CONTINUE TO AFFECT KCMX FOR THE NEXT SEVERAL
HRS WITH VIS VARYING BTWN MVFR AND IFR. LATER IN THE NIGHT...WINDS
SHOULD BACK SUFFICIENTLY TO PUSH LAKE EFFECT TO THE N OF KCMX...
LEAVING BEHIND MVFR CIGS AND LINGERING FLURRIES DUE TO WEAK
DISTURBANCE PASSING ACROSS THE AREA. AT KIWD/KSAW...VFR CONDITIONS
WILL BE THE RULE. THIS AFTN/EVENING...NEXT COLD FRONT WILL PUSH
ACROSS THE UPPER LAKES...BRINGING A RETURN OF LAKE EFFECT SHSN TO
KCMX. EXPECT A PERIOD OF IFR CONDITIONS WITH FROPA LATE AFTN AT
KCMX. AT KIWD...MVFR CONDITIONS WILL RETURN LATE IN THE AFTN AS
FRONT PASSES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 PM EST MON NOV 26 2012
WITH GENERALLY WEAK CLIPPER SYSTEMS BEING THE MAIN WIND PRODUCERS
OVER THE NEXT FEW DAYS...WINDS OF 20 TO 30 KTS WILL BE COMMON BUT NO
GALES ARE EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1046 PM CST MON NOV 26 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A 1033MB HIGH
PRESSURE SYSTEM MOVING SOUTHEAST OVER THE NORTH-CENTRAL GREAT
PLAINS. NORTHWEST FLOW ALONG THE THE FRONT SIDE OF THE HIGH
CONTINUES TO PRODUCE LAKE CLOUDS AND FLURRIES OVER N-C WISCONSIN
EARLY THIS AFTERNOON...BUT THESE CLOUDS SHOULD START TO ERODE LATER
IN THE DAY AS THE SURFACE HIGH BRINGS DRIER AIR INTO THE STATE. LOW
LEVEL WARM ADVECTION IS OCCURRING UPSTREAM OVER NORTH DAKOTA AND
SOUTHERN CANADA WHERE THERE ARE A FEW REPORTS OF SNOW SHOWERS AND
FLURRIES. AS THIS WARM ADVECTION ARRIVES LATE TONIGHT INTO
TUESDAY...CLOUDS AND SNOW CHANCES ARE THE MAIN FORECAST CONCERNS.
TONIGHT...NORTHWEST FLOW TO PREVAIL TONIGHT ACROSS THE WESTERN GREAT
LAKES. WEAK SHORTWAVE EMBEDDED WITHIN THE FLOW WILL PASS OVER
NORTHERN ILLINOIS THIS EVENING WHILE HIGH PRESSURE PASSES ACROSS THE
STATE OF WISCONSIN. AS LOW LEVEL WINDS BACK AROUND TO THE
WEST...THEY WILL PUSH DRIER AIR ACROSS NORTHERN WISCONSIN AND LAKE
EFFECT CLOUDS SHOULD EXIT TO THE NORTHEAST. SO SHOULD HAVE A MOSTLY
CLEAR EVENING AND WINDS HAVE A CHANCE TO DECOUPLE...WHICH WOULD HELP
TEMPS PLUMMET OVER N-C WISCONSIN ONCE SKIES CLEAR. TEMPS UPSTREAM
IN MINNESOTA FELL NEAR ZERO...AND THINK POTENTIAL IS THERE FOR THAT
TO OCCUR. WILL TREND TEMPS LOWER. AFTER MIDNIGHT...A WEAK
SHORTWAVE WILL DROP SOUTHEAST ACROSS SOUTHERN CANADA AND WILL SEND
SCT-BKN LOW AND MID CLOUDS ACROSS THE NORTHWEST PART OF THE STATE.
FLURRIES NOTED OVER SOUTH-CENTRAL CANADA SHOULD STAY TO OUR NORTH.
ONCE THE CLOUDS ARRIVE...TEMPS MAY REBOUND A BIT. LOWS IN THE MID
SINGLE DIGITS NORTH TO THE UPPER TEENS NEAR LAKE MICHIGAN.
TUESDAY...THE SHORTWAVE ENERGY WILL DROP INTO THE WESTERN GREAT
LAKES ON TUESDAY AND WILL PUSH A COLD FRONT INTO NORTHWEST WISCONSIN
DURING THE AFTERNOON. LOW LEVEL WARM ADVECTION CLOUDS WILL LIKELY
LIFT OUT TO THE NORTHEAST IN THE MORNING. PLENTY OF MID AND HIGH
CLOUDS WILL BE AROUND TO MAKE THIS A PARTLY SUNNY TO MOSTLY CLOUDY
DAY. AHEAD OF THE FRONT...LOW CLOUDS WILL BE ON THE INCREASE OVER
N-C AND CENTRAL WISCONSIN IN THE AFTERNOON. PREVIOUS SHIFT ADDED A
CHANCE OF SNOW SHOWERS...AND THIS LOOKS GOOD. HIGHS IN THE MIDDLE
20S NORTH TO THE LOWER 30S SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY. LOOKS LIKE A
FAIRLY QUITE PERIOD OF WEATHER WITH LITTLE OR NO SNOW AND
TEMPERATURES WARMING ABOVE NORMAL.
NORTHWEST UPPER FLOW WILL KEEP TEMPERATURES NEAR NORMAL WEDNESDAY
BUT THEN UPPER FLOW WILL BACK AND BECOME ZONAL BY THE END OF THE
WEEK. A COUPLE OF WEAK SHORTWAVES ARE EXPECTED TO MOVE THROUGH
THE UPPER FLOW FRIDAY AND SATURDAY SETTING UP SOME LIGHT
OVERRUNNING PRECIPITATION. IT MAY BE COLD ENOUGH FOR SOME SNOW
FRIDAY BUT AFTER THAT IT LOOKS TOO WARM FOR ANYTHING BUT LIGHT
RAIN.
SOUTHERLY SURFACE FLOW WILL BRING UP WARM AND MOIST AIR OVER THE
COLD GROUND AND MAY PRODUCE DENSE FOG AT SOME POINT LATE IN THE
WEEK.
&&
.AVIATION...CLOUDS WILL BE ON THE INCREASE OVERNIGHT...BUT CIGS
ARE EXPECTED TO REMAIN VFR. SOME PATCHY FLURRIES MAY IMPACT THE
RHI TAF SITE LATE TONIGHT INTO EARLY TUESDAY. SCT-BKN SKY COVER
AND VFR CONDITIONS WILL CONTINUE THROUGH TUESDAY...WITH SW WINDS
GUSTING TO AROUND 20 KTS DURING THE AFTERNOON. SOME LLWS IS POSSIBLE
DURING THE EVG HOURS...IN ADVANCE OF AN APPROACHING COLD FRONT.
THE FRONT IS EXPECTED TO MOVE THROUGH RHI AROUND 03Z/WED...AND
AUW/CWA AROUND 04Z/WED. SCT SNOW SHOWERS AND FLURRIES WILL DEVELOP
ACROSS NC WI DURING THE EVG...AND MVFR CIGS WILL LIKELY ARRIVE
IN THE WAKE OF THE COLD FRONT.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW YORK NY
747 AM EST TUE NOV 27 2012
.SYNOPSIS...
WEAK LOW PRESSURE WILL PASS OFF THE SOUTHERN MID ATLANTIC COAST
THIS AFTERNOON...AND THEN SOUTHEAST OF LONG ISLAND TONIGHT WHILE
BEGINNING TO INTENSIFY. HIGH PRESSURE WILL THEN BUILD FROM THE
TENNESSEE VALLEY...AND PASS OFF THE MID ATLANTIC COAST THROUGH
THE END OF THE WEEK. A WEAKENING COLD FRONT WILL TRAVERSE THE AREA
THURSDAY NIGHT OR FRIDAY...WITH CANADIAN HIGH PRESSURE BUILDING
INTO NEW ENGLAND BEHIND IT. THE FRONT WILL STALL NEARBY...AND THEN
LIFT BACK TO THE NORTH OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
VERY TRICKY FORECAST FOR THIS SYSTEM...AND FRAUGHT WITH BUST
POTENTIAL ESPECIALLY FOR NYC METRO AND COASTAL SECTIONS...AS LOW
LEVEL THERMAL PROFILES DRIVE PRECIP TYPE DESPITE THERMAL PROFILES
ALOFT SUPPORTIVE OF SNOW.
SFC TEMPS IN NYC METRO AND ALONG THE COAST ARE IN THE UPPER
30S/LOWER 40S...AND SFC WET BULB TEMPS ARE A COUPLE DEG ABOVE
FREEZING...SO NOW THINK THESE AREAS WILL BE HARD PRESSED TO SEE
ANY SNOW UNTIL PERHAPS TONIGHT. LATEST RUNS OF THE RAP AND 06Z NAM
SUPPORT THIS IDEA AS WELL...THOUGH WE WILL HAVE TO MONITOR EFFECT
OF NORTHERLY INLAND FLOW AND POSSIBLE CORRESPONDING COASTAL FRONT
DEVELOPMENT THAT COULD IMPACT TEMPS.
FROM PREV DISCUSSION...FCST STILL CARRIES MOSTLY SNOW INLAND...
MIXING WITH RAIN IN THE AFTERNOON EXCEPT WELL NORTH/WEST OF NYC
AND IN THE HIGHER ELEVATIONS WHICH SHOULD REMAIN ALL SNOW...WITH
SUB-ADVY AMTS OF 1-2 INCHES. NYC METRO...COASTAL CT AND LONG
ISLAND SHOULD SEE PRIMARILY RAIN...WITH LITTLE IF ANY SNOW
ACCUMULATION. EXPECTING MAINLY LIGHT PRECIP WHICH WOULD PREVENT
ENTIRE COLUMN FROM COOLING AND FORCING A CHANGE BACK TO SNOW
ACROSS THE ENTIRE CWA...BUT HOW THIS WILL PLAY OUT REMAINS
UNCERTAIN...AND IS DEPENDENT ON MESOSCALE FEATURES ESPECIALLY
LATER THIS AFTERNOON AS STRONGER FRONTOGENETIC FORCING SLIDES
ACROSS. IF DYNAMIC COOLING FROM ALOFT VIA THIS FORCING WINS OUT
THEN ACCUMULATING SNOW COULD FALL ACROSS THE ENTIRE CWA...WITH
ADVY LEVEL SNOWS OF 2-3 INCHES INLAND...AND EVEN AN INCH OR TWO
FOR NYC METRO.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
PRECIP WILL CONTINUE INTO THE EVENING. P-TYPE UNCERTAIN PER NEAR
TERM SECTION...AT THE VERY LEAST INCREASING N FLOW HELPING CHANGE
P-TYPE BACK TO ALL SNOW INLAND AND AT LEAST A SNOW/RAIN MIX FOR
NYC METRO AND COASTAL SECTIONS BEFORE ENDING. MAIN ACCUMULATING
SNOWS TONIGHT SHOULD TAKE PLACE OVER INTERIOR SOUTHERN CT...WITH
AN INCH OR SO. LOWS WILL BE IN THE 20S AND 30S...WITH NYC RIGHT
AROUND THE FREEZING MARK.
WED SHOULD BECOME MOSTLY SUNNY WITH A BRISK NW FLOW. HIGH TEMPS
WILL TOP OUT IN THE LOWER AND MID 40S...NEARLY 20 DEG BELOW AVG.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
UPPER TROUGH AXIS IS FORECAST TO BE E OF THE LOCAL AREA BY 00Z THU
WITH ZONAL FLOW BECOMING ESTABLISHED ALOFT THROUGH THE REMAINDER OF
THE WEEK. DRY WEATHER IS EXPECTED WITH HIGH PRES BUILDING TO OUR
S...WITH A WEAKENING COLD FRONT APPROACHING FROM THE N THU NIGHT OR
FRI. TIMING DIFFERENCES BETWEEN THE GFS AND EC DUE TO THE STRENGTH
AND POSITION OF CANADIAN HIGH PRES BUILDING IN BEHIND IT...WHICH
DIFFER DUE TO UPSTREAM SHORTWAVE WHICH WILL EVENTUALLY TRAVERSE THE
LOCAL AREA OVER THE WEEKEND. MOISTURE IS LIMITED...SO WILL KEEP THE
FORECAST DRY AND ONLY INCREASE CLOUDS WITH THE COLD FROPA.
THE FRONT WILL BECOME STATIONARY OVER OR SOUTH OF THE AREA...BUT
WILL DEPEND ON HOW FAR S THE CANADIAN HIGH BUILDS. EC BUILDS FURTHER
S INTO NEW ENGLAND THAN THE GFS AND PUSHES THE FRONT FURTHER S. IT
IS ALSO DRIER THAN THE GFS...BUT THE GENERAL PATTERN IS THE SAME
WHERE THE HIGH SLIDES OFFSHORE AND WAA ENSUES. HAVE NOT DEVIATED
MUCH FROM THE PREVIOUS FORECAST THIS WEEKEND AND INTO EARLY NEXT
WEEK WITH THE DIFFERENCES. HOWEVER...AT THE VERY LEAST IT APPEARS TO
BE CLOUDY DURING MOST OF THIS TIME FRAME.
TEMPS BEGIN BELOW NORMAL ON THU AND FRI...IN THE 40S DURING THE DAY
AND 20S AND 30S AT NIGHT. A WARMING TREND WILL THEN BEGIN ON SAT AND
CONTINUE INTO EARLY NEXT WEEK WITH TEMPERATURES ABOVE CLIMO NORMS.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
LOW PRESSURE REMAINS TO THE SOUTH OF THE TERMINALS TODAY AS IT MOVES
ENE THROUGH TONIGHT.
MODERATE TO HIGH CONFIDENCE IN WINDS. FOR ALL TERMINALS...TIMING OF
ONSET OF PCPN AND ONSET OF LOWERING CIGS/VSBYS MAY BE AN HOUR TWO
OFF. PCPN TYPE AND SNOW ACCUM FORECASTS ARE LOW CONFIDENCE...SEE
COMMENTS BELOW.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: RA COULD PREVAIL AS EARLY AS 15-16Z. SNOW
ACCUMULATION ON RUNWAY OF UP TO AN INCH
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: CHC THAT RA COULD PREVAIL THROUGH THE ENTIRE
DAY WITH JUST PERHAPS A BRIEF PERIOD OF -RASN AT THE ONSET OF PCPN.
SNOW ACCUMULATION ON RUNWAY OF BELOW AN INCH.
KLGA FCSTER COMMENTS: CHC THAT RA COULD PREVAIL THROUGH THE ENTIRE
DAY WITH JUST PERHAPS A BRIEF PERIOD OF -RASN AT THE ONSET OF PCPN.
SNOW ACCUMULATION ON RUNWAY OF BELOW AN INCH.
KTEB FCSTER COMMENTS: CHC OF RA PREVAILING AT TIMES THIS AFTN. SNOW
ACCUMULATION ON RUNWAY OF AROUND AN INCH.
KHPN FCSTER COMMENTS: CHC OF RA PREVAILING AT TIMES THIS AFTN. SNOW
ACCUMULATION ON RUNWAY OF AROUND AN INCH.
KISP FCSTER COMMENTS: CHC THAT RA COULD PREVAIL THROUGH THE ENTIRE
DAY WITH JUST PERHAPS A BRIEF PERIOD OF -RASN AT THE ONSET OF PCPN.
SNOW ACCUMULATION ON RUNWAY OF BELOW AN INCH.
.OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
.WED...VFR. NW FLOW G15-20KT.
.THU...VFR. WNW FLOW G15-20KT.
.FRI...VFR.
.SAT...MAINLY VFR...PSBL MVFR.
&&
.MARINE...
N-NW WINDS IN THE WAKE OF LOW PRESSURE PASSING SE OF LONG ISLAND
SHOULD REACH SCA CRITERIA THIS EVENING ACROSS THE OCEAN WATERS AND
THE ERN SOUND/BAYS...AND AN SCA WILL BE ISSUED FOR TONIGHT.
SCA CONDS MAY CONTINUE INTO THE MORNING ON THE ERN OCEAN
WATERS...BUT THERE SHOULD BE A RELATIVE LULL IN THE AFTERNOON
BEFORE STRONGER WINDS REDEVELOP BETWEEN THE DEPARTING LOW AND
BUILDING HIGH PRESSURE. SCA CONDS EXPECTED AGAIN WED NIGHT AND
POSSIBLY INTO THU MORNING...ESPECIALLY ON THE OCEAN WATERS MAINLY
DUE TO LINGERING SEAS. SUB-ADVY CONDS MAINLY EXPECTED
THEREAFTER...EXCEPT PERHAPS BRIEFLY BEHIND A WEAK COLD FRONT THU
NIGHT...AND FOR SEAS ON THE EASTERN OCEAN WATERS LATE SAT NIGHT
DUE TO A PERSISTENT SW FLOW.
&&
.HYDROLOGY...
LOW PRESSURE AFFECTING THE REGION THROUGH TONIGHT SHOULD BRING 1/4
TO 1/2 INCH LIQUID EQUIVALENT QPF...WITH THE HIGHEST AMOUNTS
ALONG THE COAST.
&&
.EQUIPMENT...
KOKX WSR-88D IS OUT OF SERVICE DUE TO A MAJOR NON STORM RELATED
MECHANICAL FAILURE. OSF RADAR OPERATIONS CENTER TECHS HAVE
ARRIVED TO BEGIN WORK...AND THE RADAR IS EXPECTED TO RETURN TO
SERVICE BY THE FIRST WEEK OF DECEMBER.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
WEDNESDAY FOR ANZ330-340-350-353-355.
&&
$$
SYNOPSIS...GOODMAN/24
NEAR TERM...GOODMAN
SHORT TERM...GOODMAN
LONG TERM...24
AVIATION...JC
MARINE...GOODMAN/24
HYDROLOGY...GOODMAN
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS JACKSON KY
1018 AM EST TUE NOV 27 2012
.UPDATE...
ISSUED AT 1017 AM EST TUE NOV 27 2012
CLOUDS LOOK LIKE THEY WILL BE SLOWER TO CLEAR THAN WAS FORECAST. THE
GFS IS HOLDING ONTO THEM LONGER THAN THE NAM...AND PREFER A FORECAST
WEIGHTED TOWARD THE GFS.
UPDATE ISSUED AT 630 AM EST TUE NOV 27 2012
LAST OF THE MEASURABLE PRECIPITATION IS NOW EXITING OFF TO THE EAST.
HOWEVER...NAM BUFR SOUNDINGS CONTINUE TO SHOW A DECENT LOW LEVEL
MOISTURE DEPTH. GIVEN THE REPORTS OF MIST AT THE ASOS SITES THIS
MORNING...OPTING TO KEEP A MENTION OF DRIZZLE IN THE FORECAST THROUGH
THE MORNING FOR THE SOUTHEAST TWO THIRDS OF THE AREA. IT LOOKS LIKE
THE SNOW MAY HAVE BEEN AVOIDED EVEN AT THE HIGHER ELEVATION
LOCATIONS. THUS...HAVE UPDATED TO REMOVE ANY FURTHER MENTION OF SNOW.
FINALLY...JUST TWEAKED THE TEMPERATURE CURVES A BIT THROUGH THE
MORNING TO REFLECT A BETTER LOW END TEMP. ALSO KEPT TEMPERATURES
BOTTOMED OUT THROUGH THE MORNING WITH ONGOING CLOUD COVER/DRIZZLE.
FORTUNATELY...TEMPERATURES ARE ABOVE FREEZING...SO NO REAL THREAT FOR
SLIPPERY CONDITIONS DEVELOPING WITH THE DRIZZLE. FORECAST UPDATE HAS
ALREADY BEEN SENT TO NDFD AND A NEW ZFP HAS BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
COLD FRONT CONTINUES TO MARCH SOUTHWARD ACROSS NORTHERN AND CENTRAL
KENTUCKY THIS MORNING. PRECIPITATION IS ALREADY STARTING TO END FROM
WEST TO EAST AND WILL CONTINUE TO END THROUGH DAYBREAK...HOLDING ON
ACROSS THE FAR EAST AND SOUTHEAST UNTIL ABOUT 13Z. HRRR SEEMS IN
PRETTY GOOD AGREEMENT WITH CURRENT PRECIPITATION TRENDS AND HAS A
VERY GOOD HANDLE ON ENDING OF PRECIPITATION THIS MORNING. AS IT
STANDS NOW...IT APPEARS PRECIPITATION SHOULD PULL OUT OF THE AREA
PRIOR TO A CHANGEOVER TO SNOW. THE ONLY EXCEPTION TO THIS MAY BE NEAR
THE VIRGINIA BORDER AND ONLY IN ELEVATIONS ABOVE 2000 FEET.
REGARDLESS...WITH ONLY LIGHT PRECIPITATION TOTALS ANTICIPATED AND
WARM SURFACE TEMPERATURES (ABOVE FREEZING)...NOT ANTICIPATING ANY
SNOWFALL ACCUMULATIONS. WE HAVE SEEN A CHANGEOVER TO SNOW AT
CVG...BUT THIS CHANGEOVER TO THE SOUTH WILL NOT PROGRESS FAST
ENOUGH. TEMPERATURES WILL STILL COOL INTO THE LOWER 30S IN THE NORTH
PRIOR TO DAYBREAK...SO STILL GOING TO BE PLENTY COOL. GIVEN THE COLD
ADVECTION TODAY...AND POSSIBLE LINGERING CLOUD COVER...HAVE WENT
BELOW GUIDANCE FOR HIGHS TODAY...GENERALLY AROUND 40 FOR MOST AREAS.
SKIES WILL CLEAR THIS AFTERNOON AND EVENING...WITH A COLD NIGHT
EXPECTED TONIGHT. A FAST MOVING WAVE IS EXPECTED TO PUSH ACROSS THE
NORTHERN OHIO RIVER VALLEY...BUT CLOUD COVER FROM THIS SYSTEM WILL
REMAIN NORTH OF KENTUCKY. THUS...WE SHOULD DECOUPLE NICELY TONIGHT IN
THE VALLEYS WITH TEMPERATURES FALLING WELL INTO THE 20S. CONTINUED TO
GO BELOW GUIDANCE FOR HIGHS ON WEDNESDAY GIVEN VERY LITTLE
IMPROVEMENT IN THE COOL AIR MASS OVER THE AREA. MODELS MAY BE TOO
AGGRESSIVE ON BRINGING THE WARMER WEATHER BACK INTO EASTERN KENTUCKY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
SURFACE HIGH PRESSURE OVER EASTERN KY AND A 50 H TROF OVER NEW
ENGLAND WITH RIDGING BUILDING INTO THE MIDWEST WILL BEGIN THE
EXTENDED FORECAST WITH COOL BUT FAIR WEATHER. HIGH TEMPS WILL SLOWLY
CLIMB INTO THE LOWER 50S AFTER A COLD NIGHT GENERALLY IN THE UPPER
20S. BY THURSDAY NIGHT THE SURFACE HIGH WILL BE LOCATED OFF THE
CAROLINA COAST WITH SOUTHERLY WINDS AND TEMPERATURES ONLY FALLING
INTO THE LOWER 30S. THEN ON FRIDAY A 50H DISTURBANCE WILL SWEEP THRU
THE OHIO VALLEY AND BRING A LOW CHANCE FOR RAIN TO EASTERN KY.
RAINFALL SHOULD BE LIGHT AND WITH CONTINUED SOUTHERLY WINDS AT THE
SFC TEMPERATURES RISE INTO THE MID AND UPPER 50S. CLOUDS AND A FEW
VERY LIGHT SHOWERS WILL LINGER INTO SAT WITH TEMPS ONLY FALLING INTO
THE LOWER 40S SAT MORNING BEFORE CLIMBING INTO THE UPPER 50S. ANOTHER
FAST MOVING SHORT WAVE WILL SWEEP THRU THE OHIO VALLEY ON SUN WITH
EARLY MORNING TEMPS IN THE UPPER 40S AND DAYTIME HIGHS IN THE LOWER
60S. THE RAIN MAY LINGER THRU SUN NIGHT BUT THE UPPER WEATHER PATTERN
WILL BEGIN TO SHIFT FROM A FAST ZONAL FLOW TO A MORE AMPLIFIED
PATTERN WITH 50H RIDGING BUILDING INTO THE MISS RIVER VALLEY. THAT
KEEPS NORTHWEST FLOW OVER THE AREA FOR SUNDAY NIGHT WITH CONTINUES
LIGHT RAIN POSSIBLE AS TEMPERATURES MONDAY MORNING ONLY FALL INTO THE
UPPER 40S WITH CONTINUED SW FLOW. LOOK FOR SOME CLEARING ON MONDAY AS
THE 50H RIDGE BUILDS INTO THE OHIO VALLEY AND TEMPERATURES SOAR INTO
THE MID 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM EST TUE NOV 27 2012
COLD FRONT WILL MARCH SOUTHWARD ACROSS EASTERN KENTUCKY THIS MORNING.
CIGS WILL REMAIN BELOW AIRPORT MINIMUMS THROUGH MUCH OF THE MORNING.
CIGS WILL IMPROVE BACK TO VFR AND CLEAR BY EARLY TO MID
AFTERNOON. THE VFR CONDITIONS WILL LINGER THROUGH TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...KAS
LONG TERM....DUSTY
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
630 AM EST TUE NOV 27 2012
.UPDATE...
ISSUED AT 630 AM EST TUE NOV 27 2012
LAST OF THE MEASURABLE PRECIPITATION IS NOW EXITING OFF TO THE EAST.
HOWEVER...NAM BUFR SOUNDINGS CONTINUE TO SHOW A DECENT LOW LEVEL
MOISTURE DEPTH. GIVEN THE REPORTS OF MIST AT THE ASOS SITES THIS
MORNING...OPTING TO KEEP A MENTION OF DRIZZLE IN THE FORECAST THROUGH
THE MORNING FOR THE SOUTHEAST TWO THIRDS OF THE AREA. IT LOOKS LIKE
THE SNOW MAY HAVE BEEN AVOIDED EVEN AT THE HIGHER ELEVATION
LOCATIONS. THUS...HAVE UPDATED TO REMOVE ANY FURTHER MENTION OF SNOW.
FINALLY...JUST TWEAKED THE TEMPERATURE CURVES A BIT THROUGH THE
MORNING TO REFLECT A BETTER LOW END TEMP. ALSO KEPT TEMPERATURES
BOTTOMED OUT THROUGH THE MORNING WITH ONGOING CLOUD COVER/DRIZZLE.
FORTUNATELY...TEMPERATURES ARE ABOVE FREEZING...SO NO REAL THREAT FOR
SLIPPERY CONDITIONS DEVELOPING WITH THE DRIZZLE. FORECAST UPDATE HAS
ALREADY BEEN SENT TO NDFD AND A NEW ZFP HAS BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
COLD FRONT CONTINUES TO MARCH SOUTHWARD ACROSS NORTHERN AND CENTRAL
KENTUCKY THIS MORNING. PRECIPITATION IS ALREADY STARTING TO END FROM
WEST TO EAST AND WILL CONTINUE TO END THROUGH DAYBREAK...HOLDING ON
ACROSS THE FAR EAST AND SOUTHEAST UNTIL ABOUT 13Z. HRRR SEEMS IN
PRETTY GOOD AGREEMENT WITH CURRENT PRECIPITATION TRENDS AND HAS A
VERY GOOD HANDLE ON ENDING OF PRECIPITATION THIS MORNING. AS IT
STANDS NOW...IT APPEARS PRECIPITATION SHOULD PULL OUT OF THE AREA
PRIOR TO A CHANGEOVER TO SNOW. THE ONLY EXCEPTION TO THIS MAY BE NEAR
THE VIRGINIA BORDER AND ONLY IN ELEVATIONS ABOVE 2000 FEET.
REGARDLESS...WITH ONLY LIGHT PRECIPITATION TOTALS ANTICIPATED AND
WARM SURFACE TEMPERATURES (ABOVE FREEZING)...NOT ANTICIPATING ANY
SNOWFALL ACCUMULATIONS. WE HAVE SEEN A CHANGEOVER TO SNOW AT
CVG...BUT THIS CHANGEOVER TO THE SOUTH WILL NOT PROGRESS FAST
ENOUGH. TEMPERATURES WILL STILL COOL INTO THE LOWER 30S IN THE NORTH
PRIOR TO DAYBREAK...SO STILL GOING TO BE PLENTY COOL. GIVEN THE COLD
ADVECTION TODAY...AND POSSIBLE LINGERING CLOUD COVER...HAVE WENT
BELOW GUIDANCE FOR HIGHS TODAY...GENERALLY AROUND 40 FOR MOST AREAS.
SKIES WILL CLEAR THIS AFTERNOON AND EVENING...WITH A COLD NIGHT
EXPECTED TONIGHT. A FAST MOVING WAVE IS EXPECTED TO PUSH ACROSS THE
NORTHERN OHIO RIVER VALLEY...BUT CLOUD COVER FROM THIS SYSTEM WILL
REMAIN NORTH OF KENTUCKY. THUS...WE SHOULD DECOUPLE NICELY TONIGHT IN
THE VALLEYS WITH TEMPERATURES FALLING WELL INTO THE 20S. CONTINUED TO
GO BELOW GUIDANCE FOR HIGHS ON WEDNESDAY GIVEN VERY LITTLE
IMPROVEMENT IN THE COOL AIRMASS OVER THE AREA. MODELS MAY BE TOO
AGGRESSIVE ON BRINGING THE WARMER WEATHER BACK INTO EASTERN KENTUCKY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
SURFACE HIGH PRESSURE OVER EASTERN KY AND A 50 H TROF OVER NEW
ENGLAND WITH RIDGING BUILDING INTO THE MIDWEST WILL BEGIN THE
EXTENDED FORECAST WITH COOL BUT FAIR WEATHER. HIGH TEMPS WILL SLOWLY
CLIMB INTO THE LOWER 50S AFTER A COLD NIGHT GENERALLY IN THE UPPER
20S. BY THURSDAY NIGHT THE SURFACE HIGH WILL BE LOCATED OFF THE
CAROLINA COAST WITH SOUTHERLY WINDS AND TEMPERATURES ONLY FALLING
INTO THE LOWER 30S. THEN ON FRIDAY A 50H DISTURBANCE WILL SWEEP THRU
THE OHIO VALLEY AND BRING A LOW CHANCE FOR RAIN TO EASTERN KY.
RAINFALL SHOULD BE LIGHT AND WITH CONTINUED SOUTHERLY WINDS AT THE
SFC TEMPERATURES RISE INTO THE MID AND UPPER 50S. CLOUDS AND A FEW
VERY LIGHT SHOWERS WILL LINGER INTO SAT WITH TEMPS ONLY FALLING INTO
THE LOWER 40S SAT MORNING BEFORE CLIMBING INTO THE UPPER 50S. ANOTHER
FAST MOVING SHORT WAVE WILL SWEEP THRU THE OHIO VALLEY ON SUN WITH
EARLY MORNING TEMPS IN THE UPPER 40S AND DAYTIME HIGHS IN THE LOWER
60S. THE RAIN MAY LINGER THRU SUN NIGHT BUT THE UPPER WEATHER PATTERN
WILL BEGIN TO SHIFT FROM A FAST ZONAL FLOW TO A MORE AMPLIFIED
PATTERN WITH 50H RIDGING BUILDING INTO THE MISS RIVER VALLEY. THAT
KEEPS NORTHWEST FLOW OVER THE AREA FOR SUNDAY NIGHT WITH CONTINUES
LIGHT RAIN POSSIBLE AS TEMPERATURES MONDAY MORNING ONLY FALL INTO THE
UPPER 40S WITH CONTINUED SW FLOW. LOOK FOR SOME CLEARING ON MONDAY AS
THE 50H RIDGE BUILDS INTO THE OHIO VALLEY AND TEMPERATURES SOAR INTO
THE MID 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM EST TUE NOV 27 2012
COLD FRONT WILL MARCH SOUTHWARD ACROSS EASTERN KENTUCKY THIS MORNING.
CIGS WILL REMAIN BELOW AIRPORT MINIMUMS THROUGH MUCH OF THE MORNING.
CIGS WILL IMPROVE BACK TO VFR AND CLEAR BY EARLY TO MID
AFTERNOON. THE VFR CONDITIONS WILL LINGER THROUGH TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM....DUSTY
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1011 AM EST TUE NOV 27 2012
.SYNOPSIS...
LIGHT SNOW WILL END WEST TO EAST ACROSS THE UPPER OHIO VALLEY BY
EARLY AFTERNOON...AS THE WEAK COLD FRONT EXITS EAST PAST THE
MOUNTAINS. HIGH PRESSURE WILL FOLLOW WITH DRY WEATHER INTO THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PER RECENT SURFACE AND RADAR DATA...THE POSTFRONTAL LIGHT SNOW
HAS BEEN MORE SLOWLY EXITING WEST TO EAST ACROSS THE UPPER OHIO VALLEY
THIS MORNING. SO SOME LOCALES CAN STILL GET AN ADDITIONAL THIN
COATING OF LIGHT SNOW INTO MIDDAY. HENCE HAVE EXTENDED THE WINTER
WEATHER ADVISORY FOR THE WV-MD MOUNTAINS UNTIL 12PM-1PM.
RECENT RAP MODEL OUTPUT SHOWS HIGH PRESSURE SUBSIDENCE WILL THEN PROMOTE
DRY CONDITIONS THE REST OF THE AFTERNOON.
DUE TO LINGERING LIGHT SNOW AND THICKER CLOUDS...CONTINUE TO
EXPECT TEMPERATURES TO SHOW NO MORE THAN A 5 DEGREE RISE FROM
CURRENT READINGS FOR AFTERNOON HIGH TEMPERATURES...BASED ON BLEND
OF RECENT GFS LAMP AND HRRR MODEL OUTPUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
COLDER AIR ALOFT WILL REMAIN OVER THE REGION THROUGH MUCH OF THE
SHORT TERM...AS A SFC HIGH SLOWLY MOVES FROM THE LOWER OHIO VALLEY
INTO THE MID ATLANTIC. WITH THE FLOW ALOFT IN A WEST-NORTHWEST
DIRECTION AND 85H TEMPS WELL BELOW 0C INTO EARLY THURSDAY...EXPECT
CLOUDS TO DEVELOP ON BOTH WED AND THU...WITH TEMPS REMAINING
BELOW NORMAL.
COLD POOL ALOFT FINALLY SHIFTS NORTHEASTWARD LATER THU AND THE LL
FLOW WILL VEER TO THE SOUTH. EXPECT A DECREASE IN CLOUD COVER BY
LATE THU...WITH JUST A BIT WARMER TEMPS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UNFORTUNATELY...LONG TERM FORECAST IS LACKING CONSISTENCY BETWEEN
12Z MODELS...SO CONFIDENCE IS BELOW AVERAGE. THE PERIOD BEGINS
WITH HIGH PRESSURE CENTERED OFF THE NORTH CAROLINA COAST. FROM
THERE...MODELS DIVERGE. DEPENDING ON THE MODEL CHOICE...THERE
COULD BE A POSSIBILITY OF PRECIPITATION ANY TIME FROM FRIDAY
AFTERNOON THROUGH MONDAY. AS A RESULT...GENERALLY WENT WITH AT
LEAST SLIGHT CHANCE POPS THROUGH THE PERIOD...BUMPING UP POPS TO
CHANCE SATURDAY NIGHT THROUGH SUNDAY NIGHT. THAT PORTION OF THE
FORECAST IS ESSENTIALLY PERSISTENCE FROM THE INHERITED FORECAST.
HOWEVER...MODELS ARE IN AGREEMENT ABOUT A WARMING TREND. WHILE
FRIDAY WILL BE A COUPLE DEGREES BELOW NORMAL...EXPECT NEAR NORMAL
TEMPERATURES ON SATURDAY...AND ABOVE NORMAL TEMPERATURES FOR
SUNDAY AND MONDAY.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
PER RECENT SURFACE AND RADAR DATA THAT IS SHOWING A SLOWER EXIT
OF POSTFRONTAL LIGHT SNOW WEST TO EAST ACROSS THE UPPER OHIO
VALLEY...EXPECT SLOWER IMPROVEMENT FROM IFR TO VFR CONDITIONS LATE
THIS MORNING. HOWEVER STILL EXPECT MAINLY VFR AFTER 19Z DUE TO
SUBSIDENCE ASSOCIATED WITH INCOMING HIGH PRESSURE.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE AND VFR CONDITIONS TO CONTINUE THROUGH FRIDAY.
RESTRICTIONS POSSIBLE SATURDAY DUE TO NORTHBOUND WARM FRONTAL RAIN
SHOWERS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MDZ001.
OH...NONE.
PA...NONE.
WV...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
WVZ041.
WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR WVZ023.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
846 AM EST TUE NOV 27 2012
.SYNOPSIS...
LIGHT SNOW WILL END WEST TO EAST ACROSS THE UPPER OHIO VALLEY BY
MIDDAY AS THE WEAK COLD FRONT EXITS EAST PAST THE MOUNTAINS. HIGH
PRESSURE WILL FOLLOW WITH DRY WEATHER INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PER RECENT SURFACE AND RADAR DATA...THE POSTFRONTAL LIGHT SNOW
WILL MORE SLOWLY EXIT WEST TO EAST ACROSS THE UPPER OHIO VALLEY
THIS MORNING. THIS MAY YIELD AN ADDED THIN COATING OF LIGHT SNOW
INTO MIDDAY. HOWEVER EXPECT HIGH PRESSURE SUBSIDENCE TO PROMOTE
DRY CONDITIONS THIS AFTERNOON.
LIKEWISE FORECASTED TEMPERATURES TO SHOW NO MORE THAN A 5 DEGREE
RISE FROM CURRENT READINGS FOR AFTERNOON HIGH TEMPERATURES...BASED
ON BLEND OF RECENT GFS LAMP AND HRRR MODEL OUTPUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
COLDER AIR ALOFT WILL REMAIN OVER THE REGION THROUGH MUCH OF THE
SHORT TERM...AS A SFC HIGH SLOWLY MOVES FROM THE LOWER OHIO VALLEY
INTO THE MID ATLANTIC. WITH THE FLOW ALOFT IN A WEST-NORTHWEST
DIRECTION AND 85H TEMPS WELL BELOW 0C INTO EARLY THURSDAY...EXPECT
CLOUDS TO DEVELOP ON BOTH WED AND THU...WITH TEMPS REMAINING
BELOW NORMAL.
COLD POOL ALOFT FINALLY SHIFTS NORTHEASTWARD LATER THU AND THE LL
FLOW WILL VEER TO THE SOUTH. EXPECT A DECREASE IN CLOUD COVER BY
LATE THU...WITH JUST A BIT WARMER TEMPS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UNFORTUNATELY...LONG TERM FORECAST IS LACKING CONSISTENCY BETWEEN
12Z MODELS...SO CONFIDENCE IS BELOW AVERAGE. THE PERIOD BEGINS
WITH HIGH PRESSURE CENTERED OFF THE NORTH CAROLINA COAST. FROM
THERE...MODELS DIVERGE. DEPENDING ON THE MODEL CHOICE...THERE
COULD BE A POSSIBILITY OF PRECIPITATION ANY TIME FROM FRIDAY
AFTERNOON THROUGH MONDAY. AS A RESULT...GENERALLY WENT WITH AT
LEAST SLIGHT CHANCE POPS THROUGH THE PERIOD...BUMPING UP POPS TO
CHANCE SATURDAY NIGHT THROUGH SUNDAY NIGHT. THAT PORTION OF THE
FORECAST IS ESSENTIALLY PERSISTENCE FROM THE INHERITED FORECAST.
HOWEVER...MODELS ARE IN AGREEMENT ABOUT A WARMING TREND. WHILE
FRIDAY WILL BE A COUPLE DEGREES BELOW NORMAL...EXPECT NEAR NORMAL
TEMPERATURES ON SATURDAY...AND ABOVE NORMAL TEMPERATURES FOR
SUNDAY AND MONDAY.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
PER RECENT SURFACE AND RADAR DATA THAT IS SHOWING A SLOWER EXIT
OF POSTFRONTAL LIGHT SNOW WEST TO EAST ACROSS THE UPPER OHIO
VALLEY...EXPECT SLOWER IMPROVEMENT FROM IFR TO VFR CONDITIONS LATE
THIS MORNING. HOWEVER STILL EXPECT MAINLY VFR THIS AFTERNOON DUE
TO SUBSIDENCE ASSOCIATED WITH INCOMING HIGH PRESSURE.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE AND VFR CONDITIONS TO CONTINUE THROUGH FRIDAY.
RESTRICTIONS POSSIBLE SATURDAY DUE TO NORTHBOUND WARM FRONTAL RAIN
SHOWERS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MDZ001.
OH...NONE.
PA...NONE.
WV...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
339 PM MST TUE NOV 27 2012
.SHORT TERM...RIDGE AXIS ACROSS WESTERN UTAH WITH MODERATE WEST
TO NORTHWEST FLOW ALOFT OVER COLORADO. WINDS STILL A BIT GUSTY
ACROSS MOUNTAINS AND FOOTHILLS THOUGH HAVE BEEN SLOWLY DECREASING
DURING THE PAST FEW HOURS. STILL...A RECENT GUST OF 46 MPH NOTED
ON LOVELAND PASS AROUND 12000 FEET. GUSTS WERE REACHING RED FLAG
CRITERIA ACROSS PORTIONS OF THE FOOTHILLS AS WELL AS ACROSS SOUTH
PARK WHERE HUMIDITY READINGS WERE AROUND 10 PERCENT. MODELS SHOW
RIDGE AXIS SHIFTING EAST INTO WESTERN COLORADO DURING THE EVENING
WITH GRADIENT ALOFT GRADUALLY WEAKENING. LATEST RUC CROSS SECTIONS
INDICATING CROSS MOUNTAIN FLOW DECREASING TO AROUND 30 KTS AT
MOUNTAIN TOP. THUS...WINDS TO GRADUALLY DECREASE AS AIRMASS COOLS
AND MIXING BECOMES LIMITED. WILL LET RED FLAG WARNING EXPIRE AT
00Z AS HUMIDITY READINGS WILL BE ON THE INCREASE. OTHERWISE...
SKIES TO BECOME MAINLY CLEAR DURING THE EVENING AS WAVE CLOUD
ALONG URBAN CORRIDOR CONTINUES TO DISSIPATE. WRF SYNTHETIC
SATELLITE IMAGERY SUGGESTING A PORTION OF THE WAVE CLOUD TO
PERSIST OVERNIGHT...BEFORE SHIFTING NORTH. BASED ON LATEST
SATELLITE LOOPS...WRF IMAGERY SEEMS A BIT OVERDONE. ON
WEDNESDAY...BOTH NAM AND GFS SHOW RIDGE AXIS SHIFTING ACROSS
REMAINDER OF COLORADO DURING THE MORNING...WITH THE AXIS ALONG
EASTERN COLORADO BORDER AT 18Z. FLOW ALOFT BECOMES MORE WESTERLY
DURING THE AFTERNOON...ALLOWING THE CROSS MOUNTAIN FLOW TO
INCREASE. LATEST NAM SHOWING THE COMPONENT AT MOUNTAIN TOP AROUND
45 KTS BY 00Z. THOUGH THIS MAY BE A BIT OVERDONE...BREEZY
CONDITIONS TO AGAIN OCCUR ACROSS MOUNTAINS AND ALONG FOOTHILLS AS
WELL AS PARK COUNTY. AIRMASS WILL AGAIN BE DRY WITH LOW HUMIDITY
EAST OF THE CONTINENTAL DIVIDE. APPEARS THAT RED FLAG CONDITIONS
WILL AGAIN BE MET IN SOME AREAS OF THE FOOTHILLS AND PARK
COUNTY. BUT DOES NOT LOOK WIDESPREAD ENOUGH SO WILL HOLD OFF ON
ISSUING A WARNING. TEMPERATURE AND THICKNESS PROGS AS WELL AS
GUIDANCE INDICATING HIGHS IN THE LOWER TO MIDDLE 60S ACROSS THE
PLAINS. CURRENT TEMPERATURE GRIDS IN LINE WITH GUIDANCE AND SEEMS
REASONABLE.
.LONG TERM...MODELS HAVE A WEAK UPPER TROUGH MOVE ACROSS THE CWA
LATE WEDNESDAY NIGHT/EARLY THURSDAY MORNING. THURSDAY`S
NORTHWESTERLY FLOW ALOFT IS SHORT LIVED. IT BECOMES ZONAL AND
STAYS THAT WAY INTO THE EXTENDED PERIODS. SPEEDS ARE MODERATE
...MAINLY 50 TO 75 KNOTS THURSDAY THROUGH FRIDAY NIGHT. THE QG
VERTICAL VELOCITY FIELDS CONTINUE TO SHOW BENIGN SYNOPTIC SCALE
ENERGY WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. THE LOW LEVEL
PRESSURE AND WIND FIELDS HAVE A BRIEF SHOT OF DOWNSLOPING WITH THE
UPPER TROUGH LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. THEN THE
GRADIENT POINTS TO NORMAL DUIRNAL WIND PATTERNS WITH A BIT OF
DOWNSLOPING MIXED IN THROUGH FRIDAY NIGHT. FOR MOISTURE...THERE IS
SOME...MAINLY IN THE MID AND UPPER LEVELS FROM LATE WEDNESDAY
NIGHT THROUGH FRIDAY NIGHT. THE NAM`S MOISTURE IS A BIT BETTER
THAN THE GFS` IN THE MOUNTAINS...ESPECIALLY THURSDAY MORNING.
MODELS HAVE NO MEASURABLE PRECIPITATION PROGGED ON THE QPF FIELDS
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. NO POPS. FOR TEMPERATURES...
THURSDAY AND FRIDAY`S HIGHS LOOK CLOSE TO WEDNESDAY`S. FOR THE
LATER DAYS...SATURDAY THROUGH TUESDAY...MODELS HAVE ZONAL FLOW FOR
THE CWA SATURDAY AND SUNDAY...THEN SOUTHWESTERLY FLOW ALOFT SUNDAY
NIGHT AND MONDAY. AN UPPER TROUGH MOVES ACROSS LATE MONDAY...THEN
STRONG NORTHWESTERLY FLOW ALOFT MONDAY NIGHT AND TUESDAY. THE
TROUGH LOOKS A BIT STRONGER TODAY THAN YESTERDAY. BUT MOISTURE IS
NOT GREAT ON ANY OF THE MODELS. A COLD FRONT MOVES IN MONDAY WITH
THE TROUGH...AND BOTH MONDAY AND TUESDAY`S TEMPERATURES LOOK
CLOSER TO SEASONAL NORMALS...THAN THE WARM SATURDAY AND SUNDAY
HIGHS DO. WILL GO WITH MINOR ALPINE POPS LATE SUNDAY NIGHT AND
MONDAY...NOTHING FOR THE PLAINS ALL FOUR DAYS.
&&
.AVIATION...DOWNSLOPE WINDS BEGINNING TO WEAKEN ACROSS AREA WITH
DIA SHOWING MORE OF A SOUTHEAST COMPONENT. WINDS STILL A BIT GUSTY
AT BJC. WINDS TO CONTINUE TO WEAKEN DURING THE EVENING WITH
DRAINAGE PATTERN DEVELOPING BY 03Z. BJC MAY STILL HAVE MORE OF A
WESTERLY COMPONENT OVERNIGHT. ON WEDNESDAY...WEAK SOUTHERLY
GRADIENT EXPECTED ACROSS AREA WITH SOUTHERLY WINDS PREVAILING.
POTENTIAL FOR A WEAK ANTICYCLONE DEVELOPING IN THE DENVER AREA
DURING THE AFTERNOON WINDS MORE OF A SOUTHEAST DIRECTION AT DEN.
SPEEDS AROUND 8 KTS TO PREVAIL...THOUGH SOME GUSTS TO 20 KTS
POSSIBLE AT BJC DURING THE AFTERNOON WITH DOWNSLOPE FLOW. VFR TO
CONTINUE.
&&
.FIRE WEATHER....RED FLAG WARNING TO CONTINUE UNTIL 5 PM MST TODAY
FOR FOOTHILLS AND PARK COUNTY. WINDS STILL GUSTING IN THE 25-30
MPH IN SOME LOCATIONS WITH LOW HUMIDITY. WINDS TO GRADUALLY
DECREASE DURING THE EVENING WITH A SLOW INCREASE IN HUMIDITY. ON
WEDNESDAY...AIRMASS TO REMAIN DRY. BREEZY CONDITIONS AGAIN
EXPECTED ACROSS PORTIONS OF FOOTHILLS AND PARK COUNTY DURING THE
AFTERNOON. DOES NOT LOOK WIDESPREAD TO WARRANT A RED FLAG WARNING.
.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ214>216.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1021 AM MST TUE NOV 27 2012
.UPDATE...STRONG WEST TO NORTHWEST FLOW ALOFT CURRENTLY ACROSS
COLORADO. AFTER A BRIEF LULL IN THE WIND GUSTS...SPEEDS BEGINNING
TO INCREASE AGAIN ACROSS MOUNTAINS AND FOOTHILLS OF BOULDER...
LARIMER AND JEFFERSON COUNTIES AS WINDS ALOFT MIXES TO SURFACE.
WITH DRY AIRMASS IN PLACE...THERE WILL BE SUFFICIENT MIXING
THROUGHOUT THE DAY TO KEEP AT LEAST BREEZY CONDITIONS CONTINUING
ACROSS MOUNTAINS AND FOOTHILLS. RUC CROSS SECTIONS SHOW CROSS
MOUNTAIN FLOW OF AROUND 55 KTS AT MOUNTAIN TOP THROUGH
18Z...DECREASING TO AROUND 45 KTS AT 20Z. THUS WILL PROBABLY SEE
THE STRONGEST WINDS OCCURRING IN THIS TIME FRAME...BUT NOT
EXPECTING WINDS TO REACH HIGH WIND CRITERIA AT THIS TIME.
STILL...GUSTY DOWNSLOPE WINDS TO KEEP HUMIDITY READINGS LOW WHICH
WILL ENHANCE FIRE DANGER ALONG FOOTHILLS. RED FLAG WARNING ALREADY
IN PLACE FOR THE FOOTHILLS AND PARK COUNTY WHICH STILL LOOKS
REASONABLE. OVERALL...CURRENT FORECASTS LOOK ON TRACK...BUT WILL
PROBABLY NEED TO INCREASE WINDS A BIT ACROSS THE MOUNTAINS AND
FOOTHILLS. WAVE CLOUD ALONG URBAN CORRIDOR MAY SLOW THE EXPECTED
WARMUP...BUT ONLY BY A FEW DEGREES AS DOWNSLOPE WARMING SHOULD
OFFSET THE SLOW WARMING.
&&
.AVIATION...DOWNSLOPE PATTERN IN PLACE WITH DRAINAGE FLOW
ENHANCED. LATEST RUC SHOWING WINDS BECOMING NORTHWEST AT DEN AND
APA BY 20Z WHILE REMAINING WESTERLY AT BJC. BUT RUC ALSO INDICATES
THE POTENTIAL FOR A WEAK ANTICYCLONE DEVELOPING OVER DENVER AREA
BY 22Z WITH WIND AT DEN SHIFTING TO THE NORTHEAST. WITH THE
DOWNSLOPE FLOW AND MIXING EXPECTED...NOT SURE ABOUT THE
ANTICYCLONE. FOR NOW WILL CONTINUE WITH THE CURRENT TAF TRENDS.
&&
.FIRE WEATHER...RED FLAG WARNING IN EFFECT FOR FOOTHILLS AND PARK
COUNTY. HUMIDITY READINGS ALREADY MEETING OR GETTING CLOSE TO
CRITERIA. WINDS ALSO ON THE INCREASE. CONDITIONS TO CONTINUE
THROUGH THE DAY...BEFORE WINDS BEGIN TO DECREASE. A FEW LOCATIONS
ALONG URBAN CORRIDOR COULD REACH CRITERIA FOR A SHORT TIME...
MAINLY NEAR THE FOOTHILLS AND NEAR THE WYOMING BORDER. BUT
CONDITIONS DON`T APPEAR WIDESPREAD ENOUGH ACROSS URBAN CORRIDOR FOR
ANY RED FLAG HILITES.
&&
.PREV DISCUSSION... /ISSUED 311 AM MST TUE NOV 27 2012/
SHORT TERM...SEEMS AS WE HAVE ALREADY SEEN OUR MINIMUM
TEMPERATURES IN MOST PLACES EARLIER IN THE NIGHT/EARLY MORNING AS
WARMER TEMPERATURES MOVE IN UNDER A DRY UPPER RIDGE BUILDING
OVERHEAD. DRY DEWPOINTS ARE ALSO MOVING IN...WITH READINGS OF -10
TO -20 DEGREES F OVER THE HIGH MOUNTAINS. THESE DRY DEW POINTS
HAVE CAUSED HUMIDITIES TO PLUMMET OVER THE MOUNTAINS AND HIGHER
FOOTHILLS INTO THE TEENS TO 30 PERCENT RANGE ALREADY. WITH BREEZY
DOWNSLOPE WINDS BEING ENHANCED OVER THE EASTERN SLOPES OF THE
MOUNTAINS AND HIGHER FOOTHILLS DUE TO A SURFACE LOW DEEPENING OVER
THE PLAINS....FIRE DANGER CONCERNS HAVE INCREASED WITH HUMIDITIES
EXPECTED TO DROP FURTHER. THEREFORE WILL BE ISSUING A RED FLAG
WARNING FOR THE FOOTHILL ZONES AS WELL AS SOUTH PARK DUE TO DRIER
HUMIDITIES EXPECTED THERE COMPARED TO THE HIGH VALLEYS FURTHER
NORTH.
WITH YESTERDAYS POST COLD FRONTAL AIRMASS WASHED OUT BY THE WARMER
AND DRIER AIR DOWNSLOPING IN...TEMPERATURES TODAY WILL BE MUCH
WARMER WITH HIGHS NEAR 60 FOR THE PLAINS AND IN THE 40S FOR THE
MOUNTAINS. NO CHANCE FOR PRECIPITATION AS MOISTURE IS MEAGER AT
BEST...HOWEVER MAY SEE A FEW WAVE CLOUDS AS A BIT OF UPPER LEVEL
MOISTURE MOVES SOUTHEAST OUT OF WYOMING.
LONG TERM...UPPER LEVEL RIDGING WILL PERSIST OVER THE CENTRAL AND
SOUTHERN ROCKIES THROUGH THE WEEKEND AS A DEEP UPPER TROUGH
REMAINS OVER THE EASTERN PACIFIC. THERE SHOULD ONLY BE A COUPLE
WEAK RIPPLES MOVING THROUGH THE AREA...ONE LATE WEDNESDAY NIGHT/
THURSDAY MORNING AND ANOTHER BY FRIDAY NIGHT/SATURDAY. HOWEVER...
THEY WILL LIKELY BRING JUST A FEW MID/HIGH CLOUDS WITH LITTLE IF
ANY COOLING. THE FRIDAY NIGHT/SATURDAY WAVE MAY HAVE JUST ENOUGH
MOISTURE LEFT TO PROVIDE A SLIGHT CHANCE OF SHOWERS IN THE FAR
NORTHERN MOUNTAINS.
AS A RESULT OF THE ABOVE MENTIONED PATTERN AND PERSISTENT WESTERLY
FLOW...LOOK FOR MUCH ABOVE NORMAL TEMPERATURES TO CONTINUE THROUGH
THIS WEEKEND. WITH 700 MB TEMPERATURES ADVERTISED TO REACH THE
6-9C RANGE BY SUNDAY...WE HAVE POTENTIAL TO APPROACH RECORD HIGHS
IN THE LOWER TO MID 70S BY THEN. OF COURSE THAT WILL ALL DEPEND
ON AMOUNT OF SUNSHINE AND DOWNSLOPE WARMING...BUT ENOUGH FACTORS
COMING TOGETHER TO WARRANT A WARMER FORECAST. FIRE DANGER CONCERNS
WILL ALSO INCREASE WITH THE WARMER TEMPERATURES AND POTENTIAL FOR
STRONGER DOWNSLOPE WINDS THIS WEEKEND.
LATEST ECMWF AND GFS ENSEMBLES FINALLY SHOW A LITTLE MORE
PRONOUNCED UPPER TROUGH REACHING THE AREA EARLY NEXT WEEK. HAVE
INCLUDED A LOW CHANCE OF SNOW SHOWERS REACHING THE MOUNTAINS BY
MONDAY.
FIRE WEATHER...ISSUING A RED FLAG WARNING DUE TO BREEZY
DOWNSLOPING WINDS OVER THE EASTERN SLOPES OF THE FRONT RANGE
MOUNTAINS AS WELL AS THE MOSQUITO RANGE AND INTO THE HIGHER
FOOTHILLS. FUELS ARE LISTED AS NOT SUSCEPTIBLE IN THE MOUNTAINS
ABOVE 9000 FEET...SO WILL LIMIT THE WARNING TO THE FOOTHILLS AND
SOUTH PARK DUE TO CONDITIONS EXPECTED TO BE MET NEAR FAIRPLAY.
GUSTS OF 30 TO 45 MPH CAN BE EXPECTED WITH HUMIDITIES NEAR 10
PERCENT. SOME AREAS ARE ALREADY HITTING CRITERIA THIS
MORNING...BUT WILL DELAY THE START UNTIL 9 AM AS THE WINDS MAY
HAVE A LULL BEFORE PICKING UP AGAIN LATE MORNING.
AVIATION...VFR CONDITIONS EXPECTED THROUGH TONIGHT. DRAINAGE
WINDS THIS MORNING WILL TAKE ON MORE OF A WESTERLY COMPONENT THIS
AFTERNOON ESPECIALLY OVER KBJC AND KDEN...WHEREAS KAPA MAY STAY
LIGHT AND VARIABLE WITH A BIT OF A SOUTHEAST DIRECTION THIS
AFTERNOON. KBJC MAY SEE SOME GUSTS UP TO 20 KTS WITH A BIT OF A
DOWNSLOPE PATTERN IN EFFECT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ214>216.
&&
$$
SHORT TERM...D-L
LONG TERM....BARJENBRUCH
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
140 AM EST TUE NOV 27 2012
.UPDATE...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A BROAD AND PROGRESSIVE
UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. MAIN PATTERN CONSISTS
OF RIDGING OVER THE PACIFIC COAST/INTER-MOUNTAIN WEST FOLLOWED
DOWNSTREAM BY GENERAL TROUGHING TO THE EAST OF THE CONTINENTAL
DIVIDE. IN THE SHORT TERM...MAIN FEATURES OF INTEREST FOR OUR
FORECAST ARE SHORTWAVE ENERGY ROUNDING THE BASE OF THE MAIN LONGWAVE
TROUGH ALONG THE NORTHERN GULF COAST...AND UPPER LEVEL JET ENERGY
EXTENDING DOWN THE SPINE OF THE APPALACHIANS.
AT THE SURFACE...A WEAK COLD FRONT ASSOCIATED WITH THE PASSING UPPER
LEVEL ENERGY WILL BE APPROACHING FROM THE NORTHWEST THROUGH THE LATE
AFTERNOON/EVENING HOURS AS THE CURRENT RIDGE OF HIGH PRESSURE OVER
THE REGION RETREATS SOUTH AND EAST INTO THE ATLANTIC.
LARGE SCALE SYNOPTIC FORCING AHEAD OF THE ABOVE MENTIONED SHORTWAVE
COUPLED WITH FAVORABLE RRQ JET DYNAMICS HAVE BEEN SUPPORTING A BAND
OF RAIN TO THE NORTHWEST OF THE FORECAST AREA EXTENDING FROM THE MS
DELTA TO THE FL PANHANDLE AND SOUTH/CENTRAL GA.
&&
.SHORT TERM (TONIGHT THROUGH THURSDAY)...
THIS EVENING/TONIGHT...BAND OF RAIN TO OUR NORTHWEST WILL CONTINUE
MAKING SOME PROGRESS EASTWARD INTO THE EVENING HOURS...HOWEVER THERE
IS GOOD NWP AGREEMENT IN AN OVERALL WEAKENING AND EVENTUAL
DISSIPATION BEFORE ANY SIGNIFICANT IMPACT CAN ARRIVE IN OUR NORTHERN
ZONES. THIS SCENARIO MAKES SENSE WITH THE BEST DEEP LAYER MOISTURE
PASSING TO OUR NORTH AND THE SLOW NORTHEASTWARD RETREAT OF THE
INITIAL JET DYNAMICS.
GFS/ECMWF BOTH SHOW AT LEAST SOME DEEP LAYER QG FORCING PASSING OVER
THE NORTHERN HALF OF THE FORECAST AREA TONIGHT WITH THE ACTUAL
SHORTWAVE PASSAGE. WITH THIS IN MIND...ALONG WITH WEAK LOW LEVEL
FRONTAL FOCUS...CAN NOT RULE OUT A FEW SHOWERS TO THE NORTH OF TAMPA
BAY OVERNIGHT...AND ESPECIALLY UP TOWARD LEVY COUNTY. DOUBTFUL THAT
MANY LOCATIONS WILL SEE ANY MEASURABLE PRECIP...BUT HIRES CONVECTION
ALLOWING GUIDANCE SUITE DOES SUGGEST AT LEAST A FEW SURVIVING
SHOWERS. THERMAL RIDGE AHEAD OF THE FRONT WILL HELP KEEP
TEMPERATURES UP FOR A WHILE TONIGHT BEFORE SOME CAA BEGINS TO FILTER
IN LATE. EARLY MORNING LOW TEMPS WILL GENERALLY RUN IN THE MIDDLE
50S TO AROUND 60. FAR NORTHERN AREAS MAY BRIEFLY DIP DOWN TOWARD 50.
HAVE KEPT PATCHY FOG IN THE GRIDS. FOG POTENTIAL WILL DEPEND ON
EXACT FRONTAL TIMING LATE TONIGHT...AND WILL LET THE NEXT SHIFT
RE-EVALUATE THE POTENTIAL FOR ANY SIGNIFICANT VIS RESTRICTIONS.
WEDNESDAY...UPPER LEVEL ENERGY QUICKLY TRANSLATES EASTWARD EARLY
WEDNESDAY ALLOWING THE PATTERN TO FLATTEN OVER THE PENINSULA.
SIGNIFICANT DRYING OF THE DEEP LAYER COLUMN WILL THEN ADVECT
SOUTHWARD ACROSS THE AREA DURING THE DAY. LOOK FOR DECREASING CLOUDS
FROM NORTH TO SOUTH FAIRLY QUICKLY. GOOD DIURNAL MIXING AND NO LACK
OF SOLAR INSOLATION WILL ALLOW TEMPS TO REACH THE LOWER TO MID 70S
NORTH OF I-4...AND MID 70S TO AROUND 80 SOUTH OF TAMPA BAY.
WEDNESDAY NIGHT THROUGH THURSDAY...SEASONABLE AND GENERALLY DRY
CONDITIONS EXPECTED. STRONG HIGH PRESSURE TO OUR NORTH WILL PROVIDE
A BREEZY EASTERLY FLOW ACROSS THE PENINSULA. LITTLE TO NO SYNOPTIC
FORCING WILL PREVENT ANY ORGANIZED SHOWER ACTIVITY. ONSHORE FLOW AND
SOME LOW LEVEL MOISTURE SHOULD RESULT IN SPEED CONVERGENCE FOCUS
SHOWERS ALONG THE EAST COAST FROM TIME TO TIME. BEST CHANCES ARE FOR
ANY OF THESE WEAK SHOWERS TO DISSIPATE BEFORE REACHING OUR ZONES AND
WILL KEEP RAIN CHANCES AT OR BELOW 10% THROUGH THE DURATION OF THE
PERIOD.
&&
.LONG TERM (FRIDAY - MONDAY)...
A WEAK UPPER LEVEL RIDGE ACROSS THE AREA SLIDES EAST AS NEARLY
ZONAL FLOW MOVES INTO THE REGION...FOLLOWED BY A SLIGHTLY STRONGER
UPPER RIDGE FOR SUN/MON. THIS PATTERN WILL PROVIDE A WARM DRY AND
STABLE ATMOSPHERE. SURFACE HIGH PRESSURE HANGING OVER/OFF THE
EASTERN SEABOARD...AND GETTING REINFORCED FROM THE NORTH EARLY IN
THE WEEKEND...MAINTAINS A ROBUST AT TIMES ENE TO EAST FLOW WITH A
GRADUAL INCREASE IN LOW LEVEL MOISTURE. THERE IS ENOUGH OF A
MOISTURE INCREASE TO SUGGEST A STRAY SHOWER OR 2 BUT WILL KEEP POPS
AT 10 PERCENT OF LESS. TEMPERATURES WILL RUN ABOVE NORMAL BY UP TO
2-4 DEGREES.
&&
.AVIATION...
VFR CONDITIONS MUCH OF PERIOD WITH THE EXCEPTION OF 5SM BR 10-14Z IN
LAKELAND AND PUNTA GORDA. HIGH CLOUDS TO LIMIT FOG POTENTIAL TO
AREAS AWAY FROM COAST. PRECIP IN FLORIDA PAN HANDLE THIS AFTERNOON
TO MOVE NORTH OF AREA TONIGHT. ASSOCIATED COLD FRONT TO WEAKEN...
REMAIN DRY...AND MOVE SOUTH OF FORT MYERS BY 12Z.
&&
.MARINE...
A WEAK COLD FRONT WILL PASS THROUGH THE EASTERN GULF OF MEXICO
TONIGHT THROUGH EARLY WEDNESDAY VEERING WINDS AROUND TO THE NORTH
AND NORTHEAST WITH TIME. A STRONG AREA OF HIGH PRESSURE WILL BUILD
TO THE NORTH OF THE REGION IN THE WAKE OF THIS FRONT ON WEDNESDAY
AND THEN SLIDE EAST TO THE MID-ATLANTIC COAST BY THE END OF THE
WEEK. ELEVATED EASTERLY FLOW IS ANTICIPATED TO DEVELOP AROUND THIS
HIGH FOR THE SECOND HALF OF THE WEEK. EASTERLY WINDS ARE LIKELY TO
REACH CAUTIONARY LEVELS AT TIMES THROUGH AT LEAST THE FIRST HALF OF
THE UPCOMING WEEKEND.
&&
.FIRE WEATHER...
A WEAK COLD FRONT WILL PASS THROUGH THE REGION TONIGHT AND EARLY
WEDNESDAY WITH ONLY A SLIGHT CHANCE OF A LIGHT SHOWER OR SPRINKLE.
DRIER AIR WILL BRIEFLY ATTEMPT TO FILTER IN FROM THE NORTH ON
WEDNESDAY BEFORE WINDS VEER TO THE EAST AND TRANSPORT INCREASING
ATLANTIC MOISTURE BACK INTO THE REGION. NO SIGNIFICANT FIRE WEATHER
CONCERNS ARE ANTICIPATED THROUGH AT LEAST THE FIRST HALF OF THE
UPCOMING WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 58 77 56 76 / 0 0 0 10
FMY 61 80 60 81 / 10 0 10 10
GIF 55 79 54 77 / 10 0 10 10
SRQ 60 77 57 77 / 0 0 0 0
BKV 51 77 50 77 / 10 0 0 10
SPG 62 75 59 75 / 0 0 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION...NOAH
LONG TERM...RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1100 AM EST TUE NOV 27 2012
.UPDATE...
15Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A BROAD AND PROGRESSIVE
UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. MAIN PATTERN CONSISTS
OF RIDGING OVER TH PACIFIC COAST/INTER-MOUNTAIN WEST FOLLOWED
DOWNSTREAM BY GENERAL TROUGHING TO THE EAST OF THE CONTINENTAL
DIVIDE. IN THE SHORT TERM...MAIN FEATURES OF INTEREST FOR OUR
FORECAST ARE SHORTWAVE ENERGY ROUNDING THE BASE OF THE MAIN LONGWAVE
TROUGH ALONG THE NORTHERN GULF COAST...AND UPPER LEVEL JET ENERGY
EXTENDING DOWN THE SPINE OF THE APPALACHIANS.
AT THE SURFACE...A WEAK COLD FRONT ASSOCIATED WITH THE PASSING UPPER
LEVEL ENERGY WILL BE APPROACHING FROM THE NORTHWEST THROUGH THE
AFTERNOON/EVENING HOURS AS THE CURRENT RIDGE OF HIGH PRESSURE OVER
THE REGION RETREATS SOUTH AND EAST INTO THE ATLANTIC.
LARGE SCALE SYNOPTIC FORCING AHEAD OF THE ABOVE MENTIONED SHORTWAVE
COUPLED WITH FAVORABLE RRQ JET DYNAMICS HAVE BEEN SUPPORTING A BAND
OF RAIN TO THE NORTHWEST OF THE FORECAST AREA EXTENDING FROM THE MS
DELTA TO THE FL PANHANDLE AND SOUTH/CENTRAL GA. THIS BAND OF RAIN
WILL BE MAKING SOME PROGRESS EASTWARD THE REST OF TODAY...HOWEVER
THERE IS GOOD NWP AGREEMENT IN AN OVERALL WEAKENING AND EVENTUAL
DISSIPATION BEFORE ANY SIGNIFICANT IMPACT CAN ARRIVE IN OUR NORTHERN
ZONES. THIS SCENARIO MAKES SENSE WITH THE BEST DEEP LAYER MOISTURE
PASSING TO OUR NORTH AND THE SLOW NORTHEASTWARD RETREAT OF THE
INITIAL JET DYNAMICS.
GFS/ECMWF BOTH SHOW AT LEAST SOME DEEP LAYER QG FORCING PASSING OVER
THE NORTHERN HALF OF THE FORECAST AREA TONIGHT WITH THE ACTUAL
SHORTWAVE PASSAGE. WITH THIS IN MIND...ALONG WITH THE FRONTAL
FOCUS...CAN NOT RULE OUT A FEW SHOWERS TO THE NORTH OF TAMPA BAY
OVERNIGHT...AND ESPECIALLY UP TOWARD LEVY COUNTY. DOUBTFUL THAT MANY
LOCATIONS WILL SEE ANY MEASURABLE PRECIP...BUT HIRES CONVECTION
ALLOWING GUIDANCE SUITE DOES SUGGEST AT LEAST A FEW SURVIVING
SHOWERS.
UPPER LEVEL ENERGY QUICKLY TRANSLATES EASTWARD EARLY WEDNESDAY
ALLOWING THE PATTERN TO FLATTEN OVER THE PENINSULA. SIGNIFICANT
DRYING OF THE DEEP LAYER COLUMN WILL THEN ADVECT SOUTHWARD ACROSS
THE AREA DURING THE DAY.
&&
.AVIATION...
VFR CONDITIONS MUCH OF PERIOD. MVFR VISIBILITY POSSIBLE AFTER 06Z
BUT LEFT OPTIMISTIC FOR NOW. WILL MAKE FINAL DETERMINATION IN 18Z
FORECAST.
&&
.MARINE...
A WEAK COLD FRONT WILL PASS THROUGH THE EASTERN GULF OF MEXICO
TONIGHT THROUGH EARLY WEDNESDAY VEERING WINDS AROUND TO THE NORTH
AND NORTHEAST WITH TIME. A STRONG AREA OF HIGH PRESSURE WILL BUILD
TO THE NORTH OF THE REGION IN THE WAKE OF THIS FRONT ON WEDNESDAY
AND THEN SLIDE EAST TO THE MID-ATLANTIC COAST BY THE END OF THE
WEEK. ELEVATED EASTERLY FLOW IS ANTICIPATED TO DEVELOP AROUND THIS
HIGH FOR THE SECOND HALF OF THE WEEK. EASTERLY WINDS ARE LIKELY TO
REACH CAUTIONARY LEVELS AT TIMES THROUGH AT LEAST THE FIRST HALF OF
THE UPCOMING WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 77 60 78 58 / 10 10 0 10
FMY 80 62 80 59 / 10 10 10 10
GIF 79 59 78 56 / 10 10 0 10
SRQ 77 61 79 57 / 10 10 0 10
BKV 78 51 77 49 / 10 10 0 0
SPG 76 63 76 61 / 10 10 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...NOAH
AREA FORECAST DISCUSSION
NWS JACKSON KY
1222 PM EST TUE NOV 27 2012
.UPDATE...
ISSUED AT 1222 PM EST TUE NOV 27 2012
EVEN AFTER UPDATING ONCE FOR A SLOWER CLEARING TREND...IT WAS STILL
NOT ENOUGH. HAVE SLOWED THE CLEARING TREND EVEN MORE. THE NAM HAS
MISERABLY FAILED IN ITS FORECAST FOR LOW LEVEL MOISTURE...WITH THE
HIGHER LOW LEVEL MOISTURE LINGERING LONGER IN THE GFS CERTAINLY
VERIFYING BETTER TODAY.
UPDATE ISSUED AT 1017 AM EST TUE NOV 27 2012
CLOUDS LOOK LIKE THEY WILL BE SLOWER TO CLEAR THAN WAS FORECAST. THE
GFS IS HOLDING ONTO THEM LONGER THAN THE NAM...AND PREFER A FORECAST
WEIGHTED TOWARD THE GFS.
UPDATE ISSUED AT 630 AM EST TUE NOV 27 2012
LAST OF THE MEASURABLE PRECIPITATION IS NOW EXITING OFF TO THE EAST.
HOWEVER...NAM BUFR SOUNDINGS CONTINUE TO SHOW A DECENT LOW LEVEL
MOISTURE DEPTH. GIVEN THE REPORTS OF MIST AT THE ASOS SITES THIS
MORNING...OPTING TO KEEP A MENTION OF DRIZZLE IN THE FORECAST THROUGH
THE MORNING FOR THE SOUTHEAST TWO THIRDS OF THE AREA. IT LOOKS LIKE
THE SNOW MAY HAVE BEEN AVOIDED EVEN AT THE HIGHER ELEVATION
LOCATIONS. THUS...HAVE UPDATED TO REMOVE ANY FURTHER MENTION OF SNOW.
FINALLY...JUST TWEAKED THE TEMPERATURE CURVES A BIT THROUGH THE
MORNING TO REFLECT A BETTER LOW END TEMP. ALSO KEPT TEMPERATURES
BOTTOMED OUT THROUGH THE MORNING WITH ONGOING CLOUD COVER/DRIZZLE.
FORTUNATELY...TEMPERATURES ARE ABOVE FREEZING...SO NO REAL THREAT FOR
SLIPPERY CONDITIONS DEVELOPING WITH THE DRIZZLE. FORECAST UPDATE HAS
ALREADY BEEN SENT TO NDFD AND A NEW ZFP HAS BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
COLD FRONT CONTINUES TO MARCH SOUTHWARD ACROSS NORTHERN AND CENTRAL
KENTUCKY THIS MORNING. PRECIPITATION IS ALREADY STARTING TO END FROM
WEST TO EAST AND WILL CONTINUE TO END THROUGH DAYBREAK...HOLDING ON
ACROSS THE FAR EAST AND SOUTHEAST UNTIL ABOUT 13Z. HRRR SEEMS IN
PRETTY GOOD AGREEMENT WITH CURRENT PRECIPITATION TRENDS AND HAS A
VERY GOOD HANDLE ON ENDING OF PRECIPITATION THIS MORNING. AS IT
STANDS NOW...IT APPEARS PRECIPITATION SHOULD PULL OUT OF THE AREA
PRIOR TO A CHANGEOVER TO SNOW. THE ONLY EXCEPTION TO THIS MAY BE NEAR
THE VIRGINIA BORDER AND ONLY IN ELEVATIONS ABOVE 2000 FEET.
REGARDLESS...WITH ONLY LIGHT PRECIPITATION TOTALS ANTICIPATED AND
WARM SURFACE TEMPERATURES (ABOVE FREEZING)...NOT ANTICIPATING ANY
SNOWFALL ACCUMULATIONS. WE HAVE SEEN A CHANGEOVER TO SNOW AT
CVG...BUT THIS CHANGEOVER TO THE SOUTH WILL NOT PROGRESS FAST
ENOUGH. TEMPERATURES WILL STILL COOL INTO THE LOWER 30S IN THE NORTH
PRIOR TO DAYBREAK...SO STILL GOING TO BE PLENTY COOL. GIVEN THE COLD
ADVECTION TODAY...AND POSSIBLE LINGERING CLOUD COVER...HAVE WENT
BELOW GUIDANCE FOR HIGHS TODAY...GENERALLY AROUND 40 FOR MOST AREAS.
SKIES WILL CLEAR THIS AFTERNOON AND EVENING...WITH A COLD NIGHT
EXPECTED TONIGHT. A FAST MOVING WAVE IS EXPECTED TO PUSH ACROSS THE
NORTHERN OHIO RIVER VALLEY...BUT CLOUD COVER FROM THIS SYSTEM WILL
REMAIN NORTH OF KENTUCKY. THUS...WE SHOULD DECOUPLE NICELY TONIGHT IN
THE VALLEYS WITH TEMPERATURES FALLING WELL INTO THE 20S. CONTINUED TO
GO BELOW GUIDANCE FOR HIGHS ON WEDNESDAY GIVEN VERY LITTLE
IMPROVEMENT IN THE COOL AIR MASS OVER THE AREA. MODELS MAY BE TOO
AGGRESSIVE ON BRINGING THE WARMER WEATHER BACK INTO EASTERN KENTUCKY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
SURFACE HIGH PRESSURE OVER EASTERN KY AND A 50 H TROF OVER NEW
ENGLAND WITH RIDGING BUILDING INTO THE MIDWEST WILL BEGIN THE
EXTENDED FORECAST WITH COOL BUT FAIR WEATHER. HIGH TEMPS WILL SLOWLY
CLIMB INTO THE LOWER 50S AFTER A COLD NIGHT GENERALLY IN THE UPPER
20S. BY THURSDAY NIGHT THE SURFACE HIGH WILL BE LOCATED OFF THE
CAROLINA COAST WITH SOUTHERLY WINDS AND TEMPERATURES ONLY FALLING
INTO THE LOWER 30S. THEN ON FRIDAY A 50H DISTURBANCE WILL SWEEP THRU
THE OHIO VALLEY AND BRING A LOW CHANCE FOR RAIN TO EASTERN KY.
RAINFALL SHOULD BE LIGHT AND WITH CONTINUED SOUTHERLY WINDS AT THE
SFC TEMPERATURES RISE INTO THE MID AND UPPER 50S. CLOUDS AND A FEW
VERY LIGHT SHOWERS WILL LINGER INTO SAT WITH TEMPS ONLY FALLING INTO
THE LOWER 40S SAT MORNING BEFORE CLIMBING INTO THE UPPER 50S. ANOTHER
FAST MOVING SHORT WAVE WILL SWEEP THRU THE OHIO VALLEY ON SUN WITH
EARLY MORNING TEMPS IN THE UPPER 40S AND DAYTIME HIGHS IN THE LOWER
60S. THE RAIN MAY LINGER THRU SUN NIGHT BUT THE UPPER WEATHER PATTERN
WILL BEGIN TO SHIFT FROM A FAST ZONAL FLOW TO A MORE AMPLIFIED
PATTERN WITH 50H RIDGING BUILDING INTO THE MISS RIVER VALLEY. THAT
KEEPS NORTHWEST FLOW OVER THE AREA FOR SUNDAY NIGHT WITH CONTINUES
LIGHT RAIN POSSIBLE AS TEMPERATURES MONDAY MORNING ONLY FALL INTO THE
UPPER 40S WITH CONTINUED SW FLOW. LOOK FOR SOME CLEARING ON MONDAY AS
THE 50H RIDGE BUILDS INTO THE OHIO VALLEY AND TEMPERATURES SOAR INTO
THE MID 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1222 PM EST TUE NOV 27 2012
LOW CLOUDS WITH LARGELY IFR CEILINGS LINGERED ACROSS THE AREA EARLY
THIS AFTERNOON. CEILINGS WILL EVENTUALLY RISE AND THEN BREAK UP FROM
NW TO SE...WITH VFR RETURNING FROM NW TO SE BETWEEN ABOUT 21Z AND
03Z. HOWEVER...CONFIDENCE IN THE TIMING FOR THIS IS WEAK.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...KAS
LONG TERM....DUSTY
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
345 PM EST TUE NOV 27 2012
.SYNOPSIS...
MIDWEST HIGH PRESSURE WILL PROMOTE DRY WEATHER INTO FRIDAY.
TEMPERATURES WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND
WEDNESDAY...BUT THEN MODERATE THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
BLEND OF RECENT SURFACE AND SATELLITE DATA SHOWS COLD POOL
STRATOCUMULUS CLOUD BANK EXTENDS AS FAR WEST AS WESTERN OHIO. RECENT
RAP AND NAM MODEL OUTPUT SHOW THIS COLD POOL CAPPED BY A SUBSIDENCE
TEMPERATURE INVERSION...TRAPPING THE CONDENSED MOISTURE. SO IT
APPEARS MORE LIKELY THAT CLOUDS CAN LINGER INTO TONIGHT ACROSS MUCH
OF THE UPPER OHIO VALLEY.
THE NAM MODEL OUTPUT SHOWS THE SUBSIDENCE CONTINUING DAYTIME
WEDNESDAY...DUE TO EASTBOUND MIDWEST HIGH PRESSURE...WHICH WILL
EVENTUALLY CAUSE CLEARING LATER TONIGHT...SO THAT MOST PARTS OF THE
UPPER OHIO VALLEY SHOULD BE MOSTLY SUNNY DAYTIME WEDNESDAY.
SOME SREF MODEL MEMBERS DO SHOW A SECONDARY COLD FRONT PASSING
EASTWARD THROUGH THE GREAT LAKES DURING WEDNESDAY...WHICH MAY CAUSE
SOME CLOUDS AND PERHAPS ISOLATED SNOW SHOWERS LATE ACROSS THE I-80
CORRIDOR OF NORTHWEST PENNSYLVANIA.
FORECASTED TEMPERATURES TO BE ABOUT 5 DEGREES COLDER THAN NORMAL
THIS PERIOD BASED ON CONSENSUS OF RECENT NAM AND GFS MOS AND SREF
MEAN VALUES.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
H8 FLOW IS EXPECTED TO BECOME ANTICYCLONIC WEDNESDAY EVENING...
LIMITING ANY LAKE EFFECT POTENTIAL TO JUST AN ISOLATED SNOW SHOWER
OR TWO ACROSS THE NORTH. HIGH PRESSURE THEN BUILDS IN THROUGH
THURSDAY NIGHT. A WEAK COLD FRONT DROPS INTO SRN NY/NRN PA
FRIDAY...BUT MOISTURE IS LIMITED SO NO SIGNIFICANT PRECIPITATION
IS EXPECTED. SLOWLY MODERATING TEMPS EXPECTED THROUGH THE PERIOD
AS WELL.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL
APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A
CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE
FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A
DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE
LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN
MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST
TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY
NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE
LONG TERM PERIOD.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
RECENT SURFACE AND SATELLITE DATA SHOWS THE MVFR COLD POOL
STRATOCUMULUS CLOUD BANK EXTENDING AS FAR WEST AS WESTERN OHIO.
RECENT RAP AND NAM MODEL OUTPUT SHOW A SUBSIDENCE-RELATED
TEMPERATURE INVERSION TRAPPING THIS CONDENSED MOISTURE. SO IT
APPEARS MORE LIKELY THAT THAT MVFR CEILINGS WILL PERSIST INTO EARLY
TONIGHT. HENCE HAVE DELAYED CLEARING TO VFR FOR MOST TAF SITES UNTIL
06Z.
NAM MODEL OUTPUT SHOWS FURTHER SUBSIDENCE ASSOCIATED WITH INCOMING
HIGH PRESSURE WILL PROMOTE VFR DAYTIME WEDNESDAY.
SURFACE WINDS WILL BE FROM THE NORTH AND NORTHWEST AT NO MORE THAN
8 KTS UNTIL 00Z...THEN EXPECT LIGHT WINDS TONIGHT. WINDS WEDNESDAY
WILL BE FROM THE WEST AT 12 KTS.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE AND VFR CONDITIONS TO CONTINUE THROUGH FRIDAY.
RESTRICTIONS POSSIBLE SATURDAY DUE TO NORTHBOUND WARM FRONTAL RAIN
SHOWERS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1219 PM EST TUE NOV 27 2012
.SYNOPSIS...
LIGHT SNOW WILL END WEST TO EAST ACROSS THE UPPER OHIO VALLEY BY
EARLY AFTERNOON...AS THE WEAK COLD FRONT EXITS EAST PAST THE
MOUNTAINS. HIGH PRESSURE WILL FOLLOW WITH DRY WEATHER INTO THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PER RECENT SURFACE AND RADAR DATA...THE POSTFRONTAL LIGHT SNOW
CONTINUES TO EXIT WEST TO EAST ACROSS THE UPPER OHIO VALLEY THIS
MORNING. THE LIGHT ACCUMULATION OF SNOW HAS JUST ABOUT ENDED.
HENCE WILL ALLOW THE REMAINING WINTER WEATHER ADVISORIES TO EXPIRE
AT 1 PM.
RECENT RAP MODEL OUTPUT SHOWS HIGH PRESSURE SUBSIDENCE WILL THEN PROMOTE
DRY CONDITIONS THE REST OF THE AFTERNOON.
DUE TO LINGERING LIGHT SNOW AND THICKER CLOUDS...CONTINUE TO
EXPECT TEMPERATURES TO SHOW NO MORE THAN A 3 OR 4 DEGREE RISE FROM
CURRENT READINGS FOR AFTERNOON HIGH TEMPERATURES...BASED ON BLEND
OF RECENT GFS LAMP AND HRRR MODEL OUTPUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
COLDER AIR ALOFT WILL REMAIN OVER THE REGION THROUGH MUCH OF THE
SHORT TERM...AS A SFC HIGH SLOWLY MOVES FROM THE LOWER OHIO VALLEY
INTO THE MID ATLANTIC. WITH THE FLOW ALOFT IN A WEST-NORTHWEST
DIRECTION AND 85H TEMPS WELL BELOW 0C INTO EARLY THURSDAY...EXPECT
CLOUDS TO DEVELOP ON BOTH WED AND THU...WITH TEMPS REMAINING
BELOW NORMAL.
COLD POOL ALOFT FINALLY SHIFTS NORTHEASTWARD LATER THU AND THE LL
FLOW WILL VEER TO THE SOUTH. EXPECT A DECREASE IN CLOUD COVER BY
LATE THU...WITH JUST A BIT WARMER TEMPS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UNFORTUNATELY...LONG TERM FORECAST IS LACKING CONSISTENCY BETWEEN
12Z MODELS...SO CONFIDENCE IS BELOW AVERAGE. THE PERIOD BEGINS
WITH HIGH PRESSURE CENTERED OFF THE NORTH CAROLINA COAST. FROM
THERE...MODELS DIVERGE. DEPENDING ON THE MODEL CHOICE...THERE
COULD BE A POSSIBILITY OF PRECIPITATION ANY TIME FROM FRIDAY
AFTERNOON THROUGH MONDAY. AS A RESULT...GENERALLY WENT WITH AT
LEAST SLIGHT CHANCE POPS THROUGH THE PERIOD...BUMPING UP POPS TO
CHANCE SATURDAY NIGHT THROUGH SUNDAY NIGHT. THAT PORTION OF THE
FORECAST IS ESSENTIALLY PERSISTENCE FROM THE INHERITED FORECAST.
HOWEVER...MODELS ARE IN AGREEMENT ABOUT A WARMING TREND. WHILE
FRIDAY WILL BE A COUPLE DEGREES BELOW NORMAL...EXPECT NEAR NORMAL
TEMPERATURES ON SATURDAY...AND ABOVE NORMAL TEMPERATURES FOR
SUNDAY AND MONDAY.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
PER RECENT SURFACE AND RADAR DATA...THAT IS SHOWING THE
POSTFRONTAL BAND OF LIGHT SNOW AND CLOUDS CONTINUING TO SLOWLY
EXIT WEST TO EAST ACROSS THE UPPER OHIO VALLEY...HAVE CONTINUED TO
FORECAST A TREND TOWARD IMPROVING FLIGHT CONDITIONS THIS
AFTERNOON...WITH ALL TAF SITES VFR BY 22Z.
SUBSIDENCE ASSOCIATED WITH INCOMING HIGH PRESSURE WILL PROMOTE VFR
TONIGHT AND DAYTIME WEDNESDAY.
SURFACE WINDS WILL BE FROM THE NORTH AND NORTHWEST AT NO MORE THAN
8 KTS UNTIL 00Z...THEN EXPECT LIGHT WINDS TONIGHT. WINDS WEDNESDAY
WILL BE FROM THE WEST AT 12 KTS.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE AND VFR CONDITIONS TO CONTINUE THROUGH FRIDAY.
RESTRICTIONS POSSIBLE SATURDAY DUE TO NORTHBOUND WARM FRONTAL RAIN
SHOWERS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MDZ001.
OH...NONE.
PA...NONE.
WV...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
WVZ041.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
216 PM CST TUE NOV 27 2012
.DISCUSSION...
THERE WAS SOME ENHANCEMENT OF THE -SN ACROSS THE NE FA EARLIER
TODAY AS A FAIRLY POTENT SHRTWV MOVED SE THRU EASTERN MN. MOST OF THIS
ACTIVITY HAS MOVED INTO NW WI...WITH MAINLY CLDS HOLDING ON IN THE
EASTERN 1/3 OF THE FA. WHERE SKIES CLEARED EARLIER IN PORTIONS OF
CENTRAL/SW/SC MN...TEMPS MANAGED TO RISE INTO THE 40S...WITH AREAS
IN THE EAST HOLDING IN THE UPPER 20S/LOWER 30S WHERE CLOUDS
REMAIN. THE WEAK FRONT WAS MOVING ACROSS THE NW FA AS OF 2 PM. THE
MAIN COLD FRONT REMAINS ACROSS N MN WHERE TEMPS HAVE HELD STEADY
OR FELL A DEGREE OR TWO.
THE MAIN FORECAST CONCERN IS WHETHER FREEZING DRIZZLE DEVELOPS
LATE THU/EARLY FRI ACROSS MOST OF THE FA...WITH THE BEST POTENTIAL
ACROSS EC MN AND WC WI WHERE THE DEPTH OF THE MOISTURE AND
STRONGER WAA WILL RESIDE. IT IS HARD TO FORECAST FREEZING
DRIZZLE...OR DRIZZLE DUE TO THE FACT THAT MODELS DO NOT GENERATE
THIS SCENARIO. THE MODELS USUALLY INCREASE THE MOISTURE...BUT WITH
VERY WEAK LIFT IN A DRIZZLE TYPE ENVIRONMENT...LITTLE OR NO
PRECIPITATION IS FORECAST. DUE TO UNCERTAINTIES IN THE DEPTH OF
THE MOISTURE AND WHETHER A STRONGER WAA REGIME DEVELOPS...HAVE
KEPT THE FORECAST IN LINE WITH ONLY AREAS OF FOG WITH PATCHY
FREEZING DRIZZLE. BUT...AGAIN THIS IS HIGHLY DEPENDENT ON THE
DEPTH OF THE MOISTURE WHERE SUPERCOOLED WATER DROPLETS FORM AND
WHETHER THESE DROPLETS COMBINED TO GENERATE DRIZZLE. ONE ITEM THAT
IS DIFFERENT IN THE MODELS THAN IN PREVIOUS RUNS IS THE FACT THAT
A VERY SMALL AREA OF QPF HAS DEVELOPED NEAR THE FA. THIS TELLS ME
THAT THERE IS A FAIRLY DEEP MOISTURE LAYER IN THE MODELS AND
ENOUGH LIFT TO GENERATE A HUNDREDTH OF AN INCH. WILL CONTINUE TO
ADVERTISE THE FREEZING DRIZZLE POTENTIAL IN THE HWO...MAINLY DUE
TO THE TIMING FOR THE MORNING COMMUTE.
PAST FRIDAY...THE ABNORMALLY MILD PATTERN WILL CONTINUE WITH
THICKNESS VALUES RISING ABV THE 550DM MARK FOR A GOOD PART OF THE
WEEKEND. SOME OF THE ENSEMBLE MEMBERS IN THE EC BIAS CORRECTED
ELEMENT HAS 60S FOR SUNDAY/MONDAY IN THE METRO AREA. ALTHOUGH THIS
TYPE OF PATTERN IS VERY CONDUCIVE FOR RECORD HIGHS FOR THIS TIME
OF YEAR...THE PROBLEM I HAVE IS THE LOW SUN ANGLE AND THE AMT OF
HRS OF POTENTIAL SUNSHINE. EVEN IF WE GET SUNSHINE...FROM MORNING
LOWS PROGGED TO FALL INTO THE 30S. A 30 DEGREE CHANGE FROM ONLY 6
HRS OF TRUE ISOLATION IS HARD TO COME BY. THE DRY PATTERN ALSO
SEEMS APPARENT WITH THE MAIN STORM TRACK TO THE NORTH OF THE
INTERNATIONAL BORDER. BOTH THE EC/GFS DO FORECAST A COLD FRONTAL
PASSAGE NEXT TUESDAY...THE MEAN UPPER FLOW WILL CONTINUE TO BE
MILD WITH ONLY A SMALL COOL DOWN AT BEST. ..JLT..
&&
.AVIATION... /18Z TAF ISSUANCE/
A WEAK FRONT WILL PASS ACROSS THE AREA THIS AFTERNOON. AT 18Z THE
FRONT EXTENDED FROM NORTHEAST MINNESOTA TO SIOUX FALLS SOUTH
DAKOTA. THE RAP AND LOCAL WRF 925-850MB PROGS INDICATING THE
POTENTIAL FOR A BKN DECK AROUND 5-6KFT...AND POSSIBLY SCT-BKN MVFR
CLOUDS MAINLY AT KAXN AND KSTC. FURTHERMORE SATELLITE AND
OBSERVATIONS SHOW CEILINGS AROUND 015-020 NORTH AND WEST OF OUR
TERMINALS WITH THAT DECK MOVING SOUTHEAST. THE QUESTION IS HOW FAR
SOUTH AND EAST WE ADVECT THOSE CEILINGS. KAXN AND KSTC ARE A
DEFINITE. FURTHER SOUTH AND EAST ARE NOT AS CLEAR CUT. THE RAP AND
NAM PUSH THIS MOISTURE TO KRWF/KMSP BUT AM NOT CONFIDENT ENOUGH AT
THIS POINT TO HAVE A CEILING IN TIME FOR THE CEILING AOB 050...BUT
IT IS A POSSIBILITY. AFTER 12Z WEDNESDAY ONLY MID AND HIGH LEVEL
CLOUDS WILL BE PRESENT.
WINDS SHIFT TO THE WEST AND NORTHWEST BETWEEN 21Z TODAY AND 02Z
WEDNESDAY AS THE FRONT PASSES. WINDS DURING THE DAY WEDNESDAY WILL
BE LIGHT AND VARIABLE BEFORE BECOMING SOUTHERLY IN THE LATE AFTERNOON.
KMSP...MID CLOUDS INCREASE AND LOWER TO ABOUT 050 AS THE FRONT APPROACHES.
THERE IS ALSO A SMALL PROBABILITY THAT A SCT MVFR LEVEL AROUND 3K
FT WILL DEVELOP WITH THE FROPA AND LINGER UNTIL 03Z WEDNESDAY.
MIGHT SEE A FEW GUSTS TO AROUND 15KTS THIS AFTERNOON BEFORE THE
FRONT MOVES THROUGH. OTHERWISE SPEEDS GENERALLY BETWEEN 5 AND 10
KTS AND THEN LIGHT AND VARIABLE AFTER 12Z WEDNESDAY.
/OUTLOOK FOR KMSP/
WED...VFR. WINDS LIGHT AND VARIABLE BECOMING S AT 5-10 KTS.
THU...VFR. WINDS ENE AT 5-10 KTS.
FRI...CHC FOR MVFR OR LOWER CIGS/VSBYS WITH FOG AND FZDZ POSSIBLE
IN THE MORNING. WINDS E 10 KTS.
SAT...CHANCE FOR MVFR OR LOWER CIGS/VSBYS WITH LIGHT RAIN...MAYBE
STARTING OUT AS LIGHT SNOW EARLY IN THE MORNING. WINDS S 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JLT/DRL
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
115 PM CST TUE NOV 27 2012
.UPDATE...
.AVIATION... /18Z TAF ISSUANCE/
A WEAK FRONT WILL PASS ACROSS THE AREA THIS AFTERNOON. AT 18Z THE
FRONT EXTENDED FROM NORTHEAST MINNESOTA TO SIOUX FALLS SOUTH
DAKOTA. THE RAP AND LOCAL WRF 925-850MB PROGS INDICATING THE
POTENTIAL FOR A BKN DECK AROUND 5-6KFT...AND POSSIBLY SCT-BKN MVFR
CLOUDS MAINLY AT KAXN AND KSTC. FURTHERMORE SATELLITE AND
OBSERVATIONS SHOW CEILINGS AROUND 015-020 NORTH AND WEST OF OUR
TERMINALS WITH THAT DECK MOVING SOUTHEAST. THE QUESTION IS HOW FAR
SOUTH AND EAST WE ADVECT THOSE CEILINGS. KAXN AND KSTC ARE A
DEFINITE. FURTHER SOUTH AND EAST ARE NOT AS CLEAR CUT. THE RAP AND
NAM PUSH THIS MOISTURE TO KRWF/KMSP BUT AM NOT CONFIDENT ENOUGH AT
THIS POINT TO HAVE A CEILING IN TIME FOR THE CEILING AOB 050...BUT
IT IS A POSSIBILITY. AFTER 12Z WEDNESDAY ONLY MID AND HIGH LEVEL
CLOUDS WILL BE PRESENT.
WINDS SHIFT TO THE WEST AND NORTHWEST BETWEEN 21Z TODAY AND 02Z
WEDNESDAY AS THE FRONT PASSES. WINDS DURING THE DAY WEDNESDAY WILL
BE LIGHT AND VARIABLE BEFORE BECOMING SOUTHERLY IN THE LATE AFTERNOON.
KMSP...MID CLOUDS INCREASE AND LOWER TO ABOUT 050 AS THE FRONT APPROACHES.
THERE IS ALSO A SMALL PROBABILITY THAT A SCT MVFR LEVEL AROUND 3K
FT WILL DEVELOP WITH THE FROPA AND LINGER UNTIL 03Z WEDNESDAY.
MIGHT SEE A FEW GUSTS TO AROUND 15KTS THIS AFTERNOON BEFORE THE
FRONT MOVES THROUGH. OTHERWISE SPEEDS GENERALLY BETWEEN 5 AND 10
KTS AND THEN LIGHT AND VARIABLE AFTER 12Z WEDNESDAY.
/OUTLOOK FOR KMSP/
WED...VFR. WINDS LIGHT AND VARIABLE BECOMING S AT 5-10 KTS.
THU...VFR. WINDS ENE AT 5-10 KTS.
FRI...CHC FOR MVFR OR LOWER CIGS/VSBYS WITH FOG AND FZDZ POSSIBLE
IN THE MORNING. WINDS E 10 KTS.
SAT...CHANCE FOR MVFR OR LOWER CIGS/VSBYS WITH LIGHT RAIN...MAYBE
STARTING OUT AS LIGHT SNOW EARLY IN THE MORNING. WINDS S 10 KTS.
&&
.PREV DISCUSSION...
/ISSUED 603 AM CST TUE NOV 27 2012/
OVERVIEW...NOT MANY CHANGES WITH THE FORECAST UPDATE THIS MORNING.
INCREASED TEMPS A FEW DEGREES IN THE EXTENDED AND SOME GUIDANCE
SUGGESTS WE COULD BE EVEN WARMER FRIDAY THROUGH MONDAY BEFORE A
STRONG COLD FRONT MOVES THROUGH THIS TIME NEXT WEEK. WE REMAIN IN
A DRY PATTERN WITH MUCH BETTER CHANCES FOR RAIN/SNOW IN NORTHERN
MINNESOTA AND NORTH OF THE CANADIAN BORDER.
IT`S JUST AS COLD IN NORTHERN KANSAS AS IT IS HERE THIS MORNING
GIVEN THE POSITION OF THE SURFACE HIGH AND THE ADVANCE OF HIGH
CLOUDS ACROSS MN/WI SINCE MIDNIGHT. THE 27.00Z MPX SOUNDING SHOWED
WARMING THROUGH ALMOST THE ENTIRE DEPTH OF THE ATMOSPHERE OVER
THE PAST 24 HOURS AND THAT`S EVEN WITH FLOW THAT IS PREDOMINATELY
NORTHWEST. WE`RE ALREADY SEEING A CHANCE EARLY THIS MORNING AT LOW
LEVELS. THE WOOD LAKE, MN PROFILER STILL SHOWS NORTHWEST 500/250MB
WINDS...BUT THE SURFACE TO 850MB FLOW IS NOW WEST-SOUTHWEST AND WE
ARE GETTING WARM AIR ADVECTION. IT WILL BE MUCH MORE MILD TODAY.
THE GFS/EC SEEMS IN BETTER AGREEMENT NOW WITH TIMING OF SHORTWAVE
ENERGY THURSDAY NIGHT. NEITHER SOLUTION SUGGESTS MUCH ACCUMULATING
PRECIP...BUT IT`S SOMETHING TO WATCH. FORECAST SOUNDINGS AND
INDICATE MOSTLY LIGHT RAIN OR DRIZZLE GIVEN THE LACK OF DEEP
MOISTURE. SURFACE TEMPS WILL BE COLD ENOUGH FOR FREEZING DRIZZLE
FOR A TIME AS WELL. AS PREVIOUSLY MENTIONED...THERE IS A STRONG
INFLUX OF MOISTURE AND WARM AIR ADVECTION WITH SATURATION BELOW
850MB.
PRETTY QUIET IN THE EXTENDED WITH ABOVE NORMAL TEMPS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
CLF/DRL
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
222 PM CST TUE NOV 27 2012
.SHORT TERM...TONIGHT AND WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SHORTWAVE
DROPPING SOUTHEAST OVER WESTERN WISCONSIN EARLY THIS AFTERNOON...AND
IS KICKING OFF SNOW SHOWERS OVER THE NW CORNER OF THE STATE. A FEW
SNOW SHOWERS LOOK RATHER BEEFY ON RADAR...AND AN OBSERVATION AT
HAYWARD DROPPED VSBYS DOWN TO A QUARTER MILE BRIEFLY. WILL BE ON
THE LOOK OUT FOR A HISA EVENT THIS AFTERNOON. COLD FRONT IS
TRAILING THE LEAD SHORTWAVE...AND IS POSITIONED FROM THE ARROWHEAD
OF MINNESOTA TO NORTHERN SOUTH DAKOTA. A WIDESPREAD LOW STRATUS
DECK EXISTS IMMEDIATELY BEHIND THIS FRONT...AND A FEW FLURRIES HAVE
BEEN NOTED ON THE OBS THERE TOO. AS SHORTWAVE ACTIVITY AND THE COLD
FRONT CROSS THE REGION TONIGHT...CLOUDS AND PRECIP CHANCES ARE THE
MAIN FORECAST CONCERNS.
TONIGHT...WEAK SHORTWAVE ACTIVITY WILL SWING ACROSS THE REGION
TONIGHT AND PUSH A COLD FRONT ACROSS THE AREA. THOUGH MOISTURE IS
GENERALLY LACKING...MOISTURE IS GREATER TO THE NORTH. RADARS SUGGEST
N-C WISCONSIN WILL SEE LIKELY SNOW SHOWERS THIS EVENING SO WILL
RAISE POPS A BIT. NOT SURE HOW FAR SOUTH TO BRING A MENTION OF
FLURRIES...BUT NORTH OF ROUTE 29 SEEMS LIKE A LOGICAL DIVIDER BASED
ON RADAR TRENDS. BEHIND THE FRONT...A LOW STRATUS DECK HAS BEEN
ADVANCING SOUTHEAST. MODELS SCOUR OUT THE LOW LEVEL MOISTURE
TONIGHT AND SUGGEST THIS STRATUS DECK MAY ONLY REACH N-C WISCONSIN.
GIVEN THE SOLID LOOK TO THE STRATUS AND THE COLD ADVECTION TO TAKE
PLACE...THINK THIS IS TOO OPTIMISTIC AND WILL BRING THE STRATUS DECK
INTO CENTRAL WISCONSIN AS WELL. BY THE TIME IT GETS THERE LATE
TONIGHT...ENOUGH DRY AIR AND DOWNSLOPING SHOULD KEEP THE STRATUS
FROM REACHING NE AND E-C WISCONSIN. NORTHWEST WINDS WILL KEEP SNOW
SHOWERS AND FLURRIES GOING OVER VILAS COUNTY THROUGH THE NIGHT
HOWEVER. A STRONGER PRESSURE GRADIENT SHOULD KEEP THE BL MIXED
ENOUGH TO GO WITH WARMER TEMPS COMPARED TO LAST NIGHT. WILL GO WITH
LOW TEENS NORTH TO NEAR 20 SE.
WEDNESDAY...PRETTY QUIET AS HIGH PRESSURE RIDGE AXIS WORKS ACROSS
THE STATE. BACKING LOW LEVEL WINDS WILL FORCE LAKE CLOUDS TO LIFT
OFF TO THE NORTHEAST AND AWAY FROM N-C WISCONSIN DURING THE
MORNING. IF LOW STRATUS DOES STICK AROUND INTO WEDNESDAY
MORNING...THINK THE INCOMING RIDGE AXIS WILL CAUSE ANY CLOUDS TO
BREAK UP EARLY IN THE PERIOD. MOST OF THE AREA SHOULD SEE MOSTLY
SUNNY CONDITIONS FOR MUCH OF THE DAY. HIGHS RANGING FROM THE MID
20S NORTH TO LOWER 30S SOUTH.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY. WINTER IS SLOW
TO ARRIVE THIS YEAR AND THE MEDIUM RANGE MODELS SUGGEST THAT THE
MILD WEATHER PATTERN WILL CONTINUE.
DRY NORTHWEST FLOW IS EXPECTED THROUGH THURSDAY WITH TEMPERATURES
RISING ABOVE NORMAL FOR THIS TIME OF THE YEAR. UPPER FLOW IS
FORECAST TO BECOME ZONAL FRIDAY THROUGH SUNDAY WITH SOME
OVERRUNNING LIGHT SNOW...DRIZZLE OR FREEZING DRIZZLE THURSDAY NIGHT
AND FRIDAY AS A WEAK SHORTWAVE TROUGH MOVES THROUGH THE FLOW.
MOISTURE IS SHALLOW AND NOT VERY ABUNDANT SO DO NOT EXPECT MUCH. A
MORE SIGNIFICANT SHORTWAVE IS EXPECTED SATURDAY AFTERNOON OR
EVENING WHICH SHOULD HAVE A BIT MORE MOISTURE AS WELL.
TEMPERATURES WILL BE WELL ABOVE FREEZING SO WHATEVER FALLS SHOULD
BE RAIN.
UPPER RIDGE REALLY BUILDS MONDAY AND SOUTHERLY LOW LEVEL FLOW
INCREASES TOO. 925MB TEMPERATURES FORECAST TO RISE TO +10C MONDAY
AFTERNOON AND EVENING WHICH COULD HELP DRIVE TEMPERATURES INTO THE
50S IF THERE IS ANY SUNSHINE AT ALL. A COLD FRONT WILL MOVE
THROUGH MONDAY NIGHT AND BRING SLIGHTLY COOLER AIR FOR TUESDAY.
&&
.AVIATION...EXPECT MAINLY VFR CONDITIONS...THOUGH MVFR CIGS AND
SNOW SHOWERS POSSIBLE IN NORTHCENTRAL WISCONSIN THIS EVENING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/RDM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
200 PM CST TUE NOV 27 2012
.SHORT TERM...THROUGH FRIDAY
200 PM CST TUE NOV 27 2012
MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES THIS EVENING AS
WELL AS THURSDAY NIGHT INTO FRIDAY.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING FROM THE BRITISH COLUMBIA COAST SOUTHWARD THROUGH THE
WESTERN U.S....WHILE TROUGHING WAS PRESENT FROM SOUTHEAST CANADA
INTO THE GREAT LAKES. IN THE NORTHWEST FLOW BETWEEN THE RIDGE AND
TROUGH...A SHORTWAVE TROUGH WAS NOTED OVER NORTHERN MINNESOTA.
ISENTROPIC LIFT DEPICTED ON THE 285-295K SURFACES AHEAD OF THE
SHORTWAVE HAS RESULTED IN SCATTERED-BROKEN ALTOSTRATUS ACROSS THE
FORECAST AREA. FARTHER NORTH...SNOW HAS BEEN FALLING ACROSS NORTHERN
MINNESOTA INTO NORTHERN WI WHERE THE DPVA AND ISENTROPIC LIFT
FORCING IS STRONGEST...ALONG WITH BETTER LOW LEVEL SATURATION PER
12Z INL SOUNDING. A COLD FRONT REPRESENTING THE SHORTWAVE AT THE
SURFACE EXTENDED FROM NORTHEAST MINNESOTA INTO SOUTHEAST SOUTH
DAKOTA. SOUTHWEST WINDS AHEAD OF THE FRONT HAS HELPED PULL WARMER
AIR INTO THE REGION...NOTED BY 925MB TEMPS THAT HAVE CLIMBED AT MPX
FROM -11C AT 00Z TO -4C AT 12Z PER SOUNDINGS. READINGS HAVE CLIMBED
INTO THE LOW TO MID 30S IN MOST LOCATIONS. BEHIND THE FRONT ACROSS
SOUTH DAKOTA...READINGS ARE NOT THAT MUCH COOLER. HOWEVER...ACROSS
SOUTHERN MANITOBA WHERE HIGH PRESSURE SITS...READINGS ARE IN THE
LOWER TEENS. 925MB TEMPS IN THIS AREA ARE -14 TO -18C PER RAP
ANALYSIS.
TONIGHT AND WEDNESDAY...THE UPPER LEVEL PATTERN IS FORECAST TO
DEAMPLIFY SOME ACROSS THE CONUS...IN RESPONSE TO A PORTION OF EAST
PACIFIC TROUGHING MOVING INTO THE WESTERN U.S.. BY 00Z THURSDAY...
500MB HEIGHTS WILL HAVE RISEN NEARLY 120 METERS OVER THE FORECAST
AREA. SUBSIDENCE ASSOCIATED WITH THESE HEIGHT RISES SHOULD KEEP THE
MAJORITY OF THE NEXT 24 HOURS QUIET. THE ONLY CONCERN IS WITH THE
SHORTWAVE OVER NORTHERN MINNESOTA DROPPING SOUTHEAST THROUGH
NORTHERN WISCONSIN THIS EVENING. THE 280-285K ISENTROPIC LIFT
HELPING TO PRODUCE THE SNOW ACROSS NORTHERN MINNESOTA WILL ACCOMPANY
THE SHORTWAVE SOUTHEASTWARD. RIGHT NOW IT APPEARS THE BULK OF THE
SNOW SHOULD STAY NORTH OF THE FORECAST AREA...PER MODEL CONSENSUS
AND SHORTWAVE TRACK...BUT AM CONCERNED AT LEAST SOME FLURRIES COULD
OCCUR OVER TAYLOR/CLARK. HAVE ADDED THE FLURRIES INTO THE FORECAST.
EVENING SHIFT WILL NEED TO WATCH THE SNOW PROGRESSION. OTHERWISE...
THE COLD FRONT LOOKS TO MOVE THROUGH MUCH OF THE FORECAST AREA BY
09Z. 925MB TEMP PROGS SUGGEST A PORTION OF THAT COLDER AIR IN
SOUTHERN MANITOBA WILL MAKE IT SOUTH INTO THE FORECAST AREA...WITH
TEMPS AT 12Z WEDNESDAY RANGING FROM -2C OVER NORTHEAST IOWA TO -8 TO
-10C IN TAYLOR COUNTY. AS SUCH...THE COLDEST READINGS TONIGHT ARE IN
TAYLOR COUNTY. THE WINDS AND SOME STRATUS CLOUDS BEHIND THE FRONT
SHOULD MITIGATE THE TEMPERATURE FALL SOMEWHAT...THOUGH. THE 925MB
TEMPS HOLD FAIRLY STEADY THROUGH ABOUT 18Z...DUE TO HIGH PRESSURE
SLIDING ACROSS... THEN BEGIN TO CLIMB. MIXING TO THE 925MB TEMPS
RESULTS IN HIGHS IN THE UPPER 20S TO NEAR 40...COLDEST ACROSS TAYLOR
AND CLARK COUNTIES. THIS MIXING SHOULD BE DOABLE DESPITE SOME
INCREASE IN HIGH CLOUDS DEPICTED IN THE AFTERNOON.
WEDNESDAY NIGHT AND THURSDAY...SOME MORE 500MB HEIGHT RISES ARE
FORECAST OVER THE AREA...IN RESPONSE TO THE WESTERN U.S. RIDGE
FLATTENING OUT AND BEING PUSHED EASTWARD BY THE PORTION OF THE EAST
PACIFIC TROUGH HEADING INTO THE DAKOTAS BY 00Z FRIDAY. SUBSIDENCE
AGAIN ASSOCIATED WITH THESE HEIGHT RISES SHOULD BE ENOUGH TO KEEP
THE AREA DRY. THIS SUBSIDENCE DOES LOOK TO CLEAR THE CIRRUS OUT
WEDNESDAY NIGHT. HOWEVER...AN INCREASE IN CIRRUS IS EXPECTED ACROSS
MUCH OF THE AREA ON THURSDAY AS THAT SHORTWAVE TROUGH COMES INTO THE
DAKOTAS. IN ADDITION...A MASS OF LOW CLOUDS IS PROGGED TO COME INTO
NORTHERN PORTIONS OF THE FORECAST AREA THURSDAY AFTERNOON. THESE ARE
IN THE WAKE OF A COLD FRONTAL PASSAGE...FORECAST TO DROP SOUTH
THROUGH THE AREA MOSTLY DURING THE MORNING. 925MB TEMPS CLIMB NICELY
WEDNESDAY NIGHT AHEAD OF THAT FRONT DROPPING SOUTH...TOPPING OUT
BETWEEN 2C AND -2C BY 12Z. THIS WARM ADVECTION COMBINED WITH A
SOUTHERLY BREEZE SHOULD HELP KEEP TEMPERATURES UP. A BLEND OF
GUIDANCE SEEMS REASONABLE FOR LOWS SUGGESTING MAINLY IN THE 20S. FOR
THURSDAY...925MB TEMPS FALL TO 0 TO -4C AT 18Z THURSDAY...THOUGH THE
WARMER NIGHT AND SOME FILTERED SUNSHINE WILL ALLOW TEMPERATURES TO
BE ABOUT 5 DEGREES WARMER THAN WEDNESDAY.
THURSDAY NIGHT AND FRIDAY...THE SHORTWAVE TROUGH ACROSS THE DAKOTAS
MODELS FORECAST TO COME ACROSS THE AREA FRIDAY MORNING. MODELS VARY
ON STRENGTH OF THE TROUGH...WITH THE 27.12Z GFS STRONGEST AND 27.12Z
NAM WEAKEST. HOWEVER...THE STRENGTH OF THE SHORTWAVE APPEARS TO HAVE
LITTLE SENSIBLE IMPACT ON THE WEATHER AS THE MID-LEVELS OF THE
ATMOSPHERE ARE SUGGESTED TO BE QUITE DRY. IN FACT...MUCH OF THE
ACTION LOOKS TO OCCUR BELOW 850MB. THE POST-FRONTAL LOW CLOUD MASS
DROPPING SOUTH THURSDAY AFTERNOON MODELS ARE IN GOOD AGREEMENT IN
HAVING IT ENCOMPASS LOCATIONS FROM I-90 NORTH BY 06Z FRIDAY. THE LOW
CLOUD DECK MAY EVEN DRIFT FARTHER SOUTH BETWEEN 06-12Z TO ENCOMPASS
MOST OF THE AREA. THE REASON THIS IS SO IMPORTANT IS THAT ISENTROPIC
LIFT PLOTS SHOW WEAK LIFT ON THE 280-285K SURFACES THURSDAY NIGHT
INTO FRIDAY MORNING. THE LIFT IN THE LOW CLOUD DECK COULD RESULT IN
SOME LIGHT FREEZING DRIZZLE DEVELOPING. SINCE THIS HAS BEEN A
CONSISTENT SIGNAL...HAVE INCLUDED THE MENTION OF IT IN THE FORECAST.
GIVEN THE IMPACTS FROM JUST A TINY BIT OF FREEZING DRIZZLE...MAY
NEED AN ADVISORY AT SOME POINT. ALSO ADDED A FOG MENTION AREA WIDE
FOR 06-18Z FRIDAY GIVEN THE VERY LOW CEILINGS PROGGED. CLOUDS LOOK
TOUGH TO CLEAR TOO FRIDAY AFTERNOON AS A GENERAL EAST-SOUTHEAST LOW
LEVEL FLOW PERSISTS. THUS...ANTICIPATING MUCH OF THIS 24 HOUR PERIOD
TO BE CLOUDY. THE CLOUDS WILL LIMIT THE DIURNAL FALL AND RISE...AND
IT IS WORTH NOTING THAT 925MB TEMPS CHANGE VERY LITTLE THROUGH
FRIDAY SUGGESTING LITTLE IN THE WAY OF ADVECTION. THUS...
TEMPERATURES SHOULD NOT CHANGE A WHOLE LOT. ONLY HAVE ABOUT A 10
DEGREE CHANGE FROM NIGHT AND DAY IN THE FORECAST.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
200 PM CST TUE NOV 27 2012
VERY GOOD MODEL AGREEMENT EXISTS AND REMAINS AMONGST THE 27.12Z
ECMWF/GFS/UKMET/CANADIAN AND GFS ENSEMBLES THROUGH MUCH OF THE LONG
TERM FORECAST...BOTH AT THE SURFACE AND ALOFT. THE UPPER LEVEL FLOW
THROUGH THE SHORT TERM PERIOD THAT IS TRANSITIONING FROM NORTHWEST
TO ZONAL BECOMES SOUTHWESTERLY FOR THE WEEKEND. THE FLOW THEN
AMPLIFIES AS A PROGRESSIVE DEEP TROUGH MARCHES ACROSS THE WEST AND
CENTRAL U.S. EARLY NEXT WEEK. MAIN PRECIPITATION TIMES OF NOTE ARE
ON SATURDAY INTO SATURDAY EVENING...AS WELL AS MONDAY INTO MONDAY
NIGHT. THE FIRST IS ASSOCIATED WITH A SHORTWAVE TROUGH COMING
THROUGH THE SOUTHWESTERLY FLOW. A SURGE OF GULF OF MEXICO MOISTURE
ACCOMPANIES THE TROUGH AS IT MOVES INTO THE AREA...ENOUGH TO LIKELY
PRODUCE A LOW LEVEL STRATUS DECK AS WELL AS SOME LIGHT
PRECIPITATION. RIGHT NOW MAYBE WE GET UP TO A TENTH OF AN INCH AT
MOST. THE MONDAY INTO MONDAY NIGHT PERIOD IS MORE INTERESTING HAVING
A DYNAMIC DEEP TROUGH COMING ACROSS. 850MB WINDS INCREASE TO 40-50
KT HELPING TO BRING 850MB DEWPOINTS UP TO 8C OR SO. ONE ISSUE IS
THAT THE SATURATION AGAIN IS ALL IN THE LOW LEVELS...AND THE
ATMOSPHERE IS CAPPED...THUS ANOTHER LIGHT RAIN/DRIZZLE EVENT WOULD
OCCUR. OVERALL...THOUGH...CONFIDENCE IN EITHER EVENT PRODUCING
WIDESPREAD QPF IS FAIRLY LOW AT THIS POINT SINCE THE DYNAMICAL
FORCING IS ALL NORTH OF THE AREA. THUS...PRECIPITATION CHANCES ARE
IN THE 20-40 RANGE.
TEMPERATURES ARE MORE INTERESTING HERE IN THE LONG TERM PERIOD.
925MB TEMPS ARE FORECAST BETWEEN 3-7C ON SATURDAY...AS MUCH AS 6-10C
ON SUNDAY PER 27.00Z/12Z ECMWF AND 10-14C BY LATE IN THE DAY MONDAY.
THE INCOMING STRATUS DECK ON BOTH SATURDAY AND MONDAY WILL LIKELY
HOLD BACK THE POTENTIAL FOR MIXING TO 925MB. HOWEVER...ADVECTION
ALONE SHOULD BE ABLE TO PUSH READINGS INTO THE MID 40S TO LOW 50S ON
SATURDAY AND INTO THE 50S EVERYWHERE ON MONDAY PER MODEL CONSENSUS.
SHOULD ANY UNEXPECTED SUNSHINE OCCUR...HIGHS COULD EASILY BE HIGHER.
MONDAYS FORECAST HIGHS ARE ONLY A FEW DEGREES BELOW RECORDS...59 AT
ROCHESTER AND 61 AT LA CROSSE. SUNDAY HAS THE BEST OPPORTUNITY FOR
SUNSHINE...AND IF THE ECMWF IS CORRECT...WE COULD EASILY CLIMB INTO
THE 50S AND PERHAPS REACH 60 IN SOUTHERN AREAS. HAVE BUMPED UP HIGHS
ABOVE THE CONSENSUS TO RANGE FROM THE MID 40S TO MID 50S. IT APPEARS
RECORDS ON SUNDAY SHOULD BE SAFE WITH ROCHESTER AT 62 AND LA CROSSE
AT 64. FOR TUESDAY...DECENT COOLING COMES IN THANKS TO THE UPPER
TROUGH SLIDING INTO THE AREA. FOLLOWED THE CONSENSUS HIGHS IN THE
40S FOR NOW.
&&
.AVIATION...THROUGH 18Z WEDNESDAY
1211 PM CST TUE NOV 27 2012
VFR CONDITIONS ARE FORECAST FOR THE TAF SITES THROUGH THE PERIOD.
A WEATHER SYSTEM WILL PASS THROUGH SOUTHERN CANADA AND SLIDE A
COLD FRONT IN FROM THE NORTH TO PROVIDE A WIND SHIFT. WHILE AHEAD
OF THE FRONT CLOUDS ARE ALL VFR...THERE IS SOME SMALL PROBABILITY OF
A LOW-LEVEL CLOUD DECK ACROSS MOVING IN BEHIND THE FRONT
OVERNIGHT. THESE CLOUDS ARE CURRENTLY SHIFTING SOUTH FROM ND AND
NWRN MN.
CONFIDENCE IS NOT HIGH THAT THIS WILL CREATE A CEILING AT
THE TAF SITES...BUT CONFIDENCE IS HIGH ENOUGH TO TREND TOWARD
CLOUDS OVERNIGHT THAT COULD FORM AN MVFR CIG. THUS...HAVE INCLUDED
A LOWER MVFR SCT CLOUD DECK IN THE FORECAST LATE TONIGHT. THIS
WILL BE THE MAIN FORECAST PROBLEM FOR FUTURE TAF FORECASTS...AND
CUSTOMERS WITH INTERESTS IN THE DAYBREAK TIME RANGE WILL WANT TO
MONITOR THOSE. AN IFR CEILING CANNOT BE RULED OUT FOR THAT TIME
FRAME EITHER...BUT THE PROBABILITIES SEEM LOW AT THIS TIME FOR IFR
CIGS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
200 PM CST TUE NOV 27 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BAUMGARDT