Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/14/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1221 PM MST THU DEC 12 2013
.UPDATE...
&&
.SHORT TERM...WILL ISSUE ANOTHER AMENDMENT TO TODAY`S FORECAST
TO ACCOUNT TO EVEN HIGHER THAN EXEPCTED MAXIMUM
TEMPERATURES...PARTICULARLY FOR FOOTHILL AND I-25 URBAN CORRIDOR
ZONES. TEMPERATURES CONTINUE TO RISE WITH MANY LOCALES IN AND NEAR
THE FOOTHILLS ALREADY IN THE MID TO UPPER 50S. SO WILL NUDGE UP
MAX TEMPS ANOTHER 2-4F IN THESE AREAS.
.PREV DISCUSSION... /ISSUED 1045 AM MST THU DEC 12 2013/
UPDATE...
SHORT TERM...FIRST PERIOD TEMPERATURES MAIN REASON FOR ADJUSTMENT
TO CURRENT FORECAST PACKAGE. MORNING TEMPERATURES HAVE BEEN
ESPECIALLY BALMY IN THE FRONT RANGE FOOTHILLS AND ARE VISIBLY
EVIDENT ON IR SATELLITE AND OF COURSE ON OBS. MID-MORNING READINGS
AT MANY FOOTHILL LOCALES ALREADY IN THE MID TO UPPER 40S. WHILE
TEMPS AT THE BASE OF THE FOOTHILLS STILL IN THE UPPER 20S AND LOWER
30S. TEMPERATURES WERE ALSO ZOOMING UP ON THE HIGHER TERRAIN OF THE
PALMER DIVIDE WHERE READINGS IN THE MID TO UPPER 40S. EAST SIDE OF
THE DENVER METRO AREA ALSO BENEFITING FROM DOWNSLOPE WARMING WHERE
SIMILAR READINGS EXIT. HAVE RAISED MAX TEMPS BY 4-7 DEGS F ON AND
ALONG THE FRONT RANGE FOOTHILLS TO ACCOUNT FOR RAPID WARMUP THIS
MORNING. OTHERWISE GENERALLY CLEAR SKIES AND GENTLE BREEZES ON TAP
FOR THE REMAINDER OF TODAY. ALTHOUGH HIGHER FOOTHILL AREAS COULD SEE
GUSTY WESTERLY WINDS DEVELOPING LATER THIS AFTERNOON.
&&
.AVIATION...VFR CONDITIONS FOR THE NEXT 24 HOURS. SOUTH-SOUTHEAST
WINDS OF 7-13KTS EXPECTED MOST OF THE TODAY FOR TERMINALS ON THE
SOUTH AND EAST SIDES OF THE DENVER METRO AREA...AND WEST-NORTHWEST
AT 5-9KTS ON THE WEST SIDE. OTHERWISE CONTINUED DRY WITH ABOVE
AVERAGE TEMPERATURES.
.PREV DISCUSSION... /ISSUED 313 AM MST THU DEC 12 2013/
SHORT TERM...DRY WNW FLOW ALOFT WILL BE OVER THE AREA TODAY THRU
TONIGHT. MAIN CONCERN FOR TODAY WILL BE HIGHS OVER NERN CO. SNOW
COVER STILL EXISTS OVER ERN LARIMER INTO CENTRAL WELD AND OVER THE
PALMER DIVIDE. OVERALL LOW LEVEL WINDS FIELDS WILL BE LIGHT SO
THERE WILL NOT BE MUCH OF A DOWNSLOPE COMPONENT OVER THE PLAINS
ALTHOUGH THERE WILL BE PLENTY OF SUN. SO THE BIG QUESTION IS WILL
THE LOW LEVEL INVERSIONS BE BKN OR NOT AS THERE WILL BE 5 TO 6
DEGREES C OF WARMING JUST ABV THE SFC.
THE NAM AND GFS PRETTY MUCH SHOW NO INVERSIONS ANYWHERE WITH
READINGS IN THE 40S ACROSS THE PLAINS WITH HIGHS IN THE LOWER 50S
AROUND DENVER. MEANWHILE THE HRRR AND TO SOME EXTENT THE RAP SHOW
INVERSIONS NOT BREAKING IN THE SNOW COVERED AREAS AS READINGS HOLD
IN THE 30S. IN ADDITION THE HRRR SHOWS QUITE A CONTRAST OVER THE
DENVER METRO AREA WITH READINGS NEAR 50 OVER THE SRN SUBURBS WHILE
IN NRN AREAS HIGHS STAY IN THE 35 TO 40 RANGE. THERE MAY END UP
BEING A WK DENVER CYCLONE WHICH ALLOWS FOR NLY SFC FLOW OVER THE NRN
SUBURBS THAT ALLOWS FOR SOME OF THE COOLER SFC TEMPS OVER WELD
COUNTY TO MOVE SOUTH SO CAN NOT COMPLETELY IGNORE WHAT THE HRRR
SHOWS. FOR NOW WILL KEEP READINGS COOLER THAN GUIDANCE FROM NORTH
OF DENVER TO FORT COLLINS TO GREELEY AND TOWARDS LIMON. FURTHER
SOUTH WILL HAVE HIGHS IN THE 45 TO 50 DEGREE RANGE AND OVER THE
FAR NERN CORNER.
LONG TERM...MODELS HAVE A COUPLE WEAK UPPER TROUGHS TO MOVE
ACROSS THE CWA. BOTH WITH SLIGHTLY COOLER AIMASSES. THE FIRST ON
FRIDAY MORNING...THEN ANOTHER FRIDAY NIGHT LATE/EARLY SATURDAY
MORNING. BY SATURDAY AFTERNOON AND NIGHT...FAIRLY STRONG
NORTHERLY FLOW ALOFT IS PROGGED. THERE IS WEAK UPWARD SYNOPTIC
SCALE ENERGY PROGGED FOR THE CWA FRIDAY INTO FRIDAY NIGHT...THEN
ALL DOWNWARD MOTION SATURDAY AND SATURDAY NIGHT. THE LOW LEVEL
WINDS ARE PROGGED TO GO TO UPSLOPE FRIDAY AFTERNOON AND EVENING.
MORE NORMAL DIURNAL PATTERNS ARE PROGGED FOR SATURDAY. FOR
MOISTURE...IN INCREASES SOMEWHAT FRIDAY...WITH THE BEST FRIDAY
EVENING OVER THE MOUNTAINS. MOISTURE DRIES OUT LATE FRIDAY
NIGHT...AND THERE ISN`T MUCH SATURDAY OR SATURDAY NIGHT. THE QPF
FIELDS SHOW A TINY AMOUNT OF MEASURABLE SNOWFALL OVER THE HIGH
MOUNTAINS FRIDAY EVENING...BUT ONLY ON THE GFS. WILL KEEP POPS IN
FRIDAY NIGHT...MOSTLY OVER JUST THE HIGH MOUNTAINS. FOR
TEMPERATURES...FRIDAY`S HIGHS ARE 2-4 C COOLER THAN TODAY`S.
SATURDAY`S ARE SIMILAR TO FRIDAY`S. FOR THE LATER DAYS...SUNDAY
THROUGH WEDNESDAY...MODELS KEEP MODERATE NORTHWESTERLY FLOW ALOFT
FOR THE CWA SUNDAY AND MONDAY. ON TUESDAY AND WEDNESDAY IT IS
WEST-NORTHWESTERLY AND INCREASES IN SPEED....ESPECIALLY ON THE
GFS. THE GFS BRINGS A JET MAXIMUM OVER THE CWA...THE ECMWF KEEPS
IT WELL NORTH AND NORTHEAST. MOISTURE IS LACKING ALL FOUR DAYS.
AVIATION...VFR TODAY AND TONIGHT. WINDS WILL BE LIGHT SLY THIS
MORNING AND MORE SSW AFTER SUNRISE. FOR THIS AFTN THERE MAY BE A
WK DENVER CYCLONE WITH WINDS BECOME MORE NNE AFTER 20Z. BY 00Z
WINDS MAY BECOME MORE ESE AND THEN BACK TO DRAINAGE BY 02Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER
LONG TERM....RPK
AREA FORECAST DISCUSSION...CORRECTION
NWS DENVER/BOULDER CO
1045 AM MST THU DEC 12 2013
.UPDATE...
&&
.SHORT TERM...FIRST PERIOD TEMPERATURES MAIN REASON FOR ADJUSTMENT
TO CURRENT FORECAST PACKAGE. MORNING TEMPERATURES HAVE BEEN
ESPECIALLY BALMY IN THE FRONT RANGE FOOTHILLS AND ARE VISIBLY
EVIDENT ON IR SATELLITE AND OF COURSE ON OBS. MID-MORNING READINGS
AT MANY FOOTHILL LOCALES ALREADY IN THE MID TO UPPER 40S. WHILE
TEMPS AT THE BASE OF THE FOOTHILLS STILL IN THE UPPER 20S AND LOWER
30S. TEMPERATURES WERE ALSO ZOOMING UP ON THE HIGHER TERRAIN OF THE
PALMER DIVIDE WHERE READINGS IN THE MID TO UPPER 40S. EAST SIDE OF
THE DENVER METRO AREA ALSO BENEFITING FROM DOWNSLOPE WARMING WHERE
SIMILAR READINGS EXIT. HAVE RAISED MAX TEMPS BY 4-7 DEGS F ON AND
ALONG THE FRONT RANGE FOOTHILLS TO ACCOUNT FOR RAPID WARMUP THIS
MORNING. OTHERWISE GENERALLY CLEAR SKIES AND GENTLE BREEZES ON TAP
FOR THE REMAINDER OF TODAY. ALTHOUGH HIGHER FOOTHILL AREAS COULD SEE
GUSTY WESTERLY WINDS DEVELOPING LATER THIS AFTERNOON.
.AVIATION...VFR CONDITIONS FOR THE NEXT 24 HOURS. SOUTH-SOUTHEAST
WINDS OF 7-13KTS EXPECTED MOST OF THE TODAY FOR TERMINALS ON THE
SOUTH AND EAST SIDES OF THE DENVER METRO AREA...AND WEST-NORTHWEST
AT 5-9KTS ON THE WEST SIDE. OTHERWISE CONTINUED DRY WITH ABOVE
AVERAGE TEMPERATURES.
&&
.PREV DISCUSSION... /ISSUED 313 AM MST THU DEC 12 2013/
SHORT TERM...DRY WNW FLOW ALOFT WILL BE OVER THE AREA TODAY THRU
TONIGHT. MAIN CONCERN FOR TODAY WILL BE HIGHS OVER NERN CO. SNOW
COVER STILL EXISTS OVER ERN LARIMER INTO CENTRAL WELD AND OVER THE
PALMER DIVIDE. OVERALL LOW LEVEL WINDS FIELDS WILL BE LIGHT SO
THERE WILL NOT BE MUCH OF A DOWNSLOPE COMPONENT OVER THE PLAINS
ALTHOUGH THERE WILL BE PLENTY OF SUN. SO THE BIG QUESTION IS WILL
THE LOW LEVEL INVERSIONS BE BKN OR NOT AS THERE WILL BE 5 TO 6
DEGREES C OF WARMING JUST ABV THE SFC.
THE NAM AND GFS PRETTY MUCH SHOW NO INVERSIONS ANYWHERE WITH
READINGS IN THE 40S ACROSS THE PLAINS WITH HIGHS IN THE LOWER 50S
AROUND DENVER. MEANWHILE THE HRRR AND TO SOME EXTENT THE RAP SHOW
INVERSIONS NOT BREAKING IN THE SNOW COVERED AREAS AS READINGS HOLD
IN THE 30S. IN ADDITION THE HRRR SHOWS QUITE A CONTRAST OVER THE
DENVER METRO AREA WITH READINGS NEAR 50 OVER THE SRN SUBURBS WHILE
IN NRN AREAS HIGHS STAY IN THE 35 TO 40 RANGE. THERE MAY END UP
BEING A WK DENVER CYCLONE WHICH ALLOWS FOR NLY SFC FLOW OVER THE NRN
SUBURBS THAT ALLOWS FOR SOME OF THE COOLER SFC TEMPS OVER WELD
COUNTY TO MOVE SOUTH SO CAN NOT COMPLETELY IGNORE WHAT THE HRRR
SHOWS. FOR NOW WILL KEEP READINGS COOLER THAN GUIDANCE FROM NORTH
OF DENVER TO FORT COLLINS TO GREELEY AND TOWARDS LIMON. FURTHER
SOUTH WILL HAVE HIGHS IN THE 45 TO 50 DEGREE RANGE AND OVER THE
FAR NERN CORNER.
LONG TERM...MODELS HAVE A COUPLE WEAK UPPER TROUGHS TO MOVE
ACROSS THE CWA. BOTH WITH SLIGHTLY COOLER AIMASSES. THE FIRST ON
FRIDAY MORNING...THEN ANOTHER FRIDAY NIGHT LATE/EARLY SATURDAY
MORNING. BY SATURDAY AFTERNOON AND NIGHT...FAIRLY STRONG
NORTHERLY FLOW ALOFT IS PROGGED. THERE IS WEAK UPWARD SYNOPTIC
SCALE ENERGY PROGGED FOR THE CWA FRIDAY INTO FRIDAY NIGHT...THEN
ALL DOWNWARD MOTION SATURDAY AND SATURDAY NIGHT. THE LOW LEVEL
WINDS ARE PROGGED TO GO TO UPSLOPE FRIDAY AFTERNOON AND EVENING.
MORE NORMAL DIURNAL PATTERNS ARE PROGGED FOR SATURDAY. FOR
MOISTURE...IN INCREASES SOMEWHAT FRIDAY...WITH THE BEST FRIDAY
EVENING OVER THE MOUNTAINS. MOISTURE DRIES OUT LATE FRIDAY
NIGHT...AND THERE ISN`T MUCH SATURDAY OR SATURDAY NIGHT. THE QPF
FIELDS SHOW A TINY AMOUNT OF MEASURABLE SNOWFALL OVER THE HIGH
MOUNTAINS FRIDAY EVENING...BUT ONLY ON THE GFS. WILL KEEP POPS IN
FRIDAY NIGHT...MOSTLY OVER JUST THE HIGH MOUNTAINS. FOR
TEMPERATURES...FRIDAY`S HIGHS ARE 2-4 C COOLER THAN TODAY`S.
SATURDAY`S ARE SIMILAR TO FRIDAY`S. FOR THE LATER DAYS...SUNDAY
THROUGH WEDNESDAY...MODELS KEEP MODERATE NORTHWESTERLY FLOW ALOFT
FOR THE CWA SUNDAY AND MONDAY. ON TUESDAY AND WEDNESDAY IT IS
WEST-NORTHWESTERLY AND INCREASES IN SPEED....ESPECIALLY ON THE
GFS. THE GFS BRINGS A JET MAXIMUM OVER THE CWA...THE ECMWF KEEPS
IT WELL NORTH AND NORTHEAST. MOISTURE IS LACKING ALL FOUR DAYS.
AVIATION...VFR TODAY AND TONIGHT. WINDS WILL BE LIGHT SLY THIS
MORNING AND MORE SSW AFTER SUNRISE. FOR THIS AFTN THERE MAY BE A
WK DENVER CYCLONE WITH WINDS BECOME MORE NNE AFTER 20Z. BY 00Z
WINDS MAY BECOME MORE ESE AND THEN BACK TO DRAINAGE BY 02Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER/RPK
LONG TERM....RPK
AVIATION...BAKER/RPK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
313 AM MST THU DEC 12 2013
.SHORT TERM...DRY WNW FLOW ALOFT WILL BE OVER THE AREA TODAY THRU
TONIGHT. MAIN CONCERN FOR TODAY WILL BE HIGHS OVER NERN CO. SNOW
COVER STILL EXISTS OVER ERN LARIMER INTO CENTRAL WELD AND OVER THE
PALMER DIVIDE. OVERALL LOW LEVEL WINDS FIELDS WILL BE LIGHT SO
THERE WILL NOT BE MUCH OF A DOWNSLOPE COMPONENT OVER THE PLAINS
ALTHOUGH THERE WILL BE PLENTY OF SUN. SO THE BIG QUESTION IS WILL
THE LOW LEVEL INVERSIONS BE BKN OR NOT AS THERE WILL BE 5 TO 6
DEGREES C OF WARMING JUST ABV THE SFC.
THE NAM AND GFS PRETTY MUCH SHOW NO INVERSIONS ANYWHERE WITH
READINGS IN THE 40S ACROSS THE PLAINS WITH HIGHS IN THE LOWER 50S
AROUND DENVER. MEANWHILE THE HRRR AND TO SOME EXTENT THE RAP SHOW
INVERSIONS NOT BREAKING IN THE SNOW COVERED AREAS AS READINGS HOLD
IN THE 30S. IN ADDITION THE HRRR SHOWS QUITE A CONTRAST OVER THE
DENVER METRO AREA WITH READINGS NEAR 50 OVER THE SRN SUBURBS WHILE
IN NRN AREAS HIGHS STAY IN THE 35 TO 40 RANGE. THERE MAY END UP
BEING A WK DENVER CYCLONE WHICH ALLOWS FOR NLY SFC FLOW OVER THE NRN
SUBURBS THAT ALLOWS FOR SOME OF THE COOLER SFC TEMPS OVER WELD
COUNTY TO MOVE SOUTH SO CAN NOT COMPLETELY IGNORE WHAT THE HRRR
SHOWS. FOR NOW WILL KEEP READINGS COOLER THAN GUIDANCE FROM NORTH
OF DENVER TO FORT COLLINS TO GREELEY AND TOWARDS LIMON. FURTHER
SOUTH WILL HAVE HIGHS IN THE 45 TO 50 DEGREE RANGE AND OVER THE
FAR NERN CORNER.
.LONG TERM...MODELS HAVE A COUPLE WEAK UPPER TROUGHS TO MOVE
ACROSS THE CWA. BOTH WITH SLIGHTLY COOLER AIMASSES. THE FIRST ON
FRIDAY MORNING...THEN ANOTHER FRIDAY NIGHT LATE/EARLY SATURDAY
MORNING. BY SATURDAY AFTERNOON AND NIGHT...FAIRLY STRONG
NORTHERLY FLOW ALOFT IS PROGGED. THERE IS WEAK UPWARD SYNOPTIC
SCALE ENERGY PROGGED FOR THE CWA FRIDAY INTO FRIDAY NIGHT...THEN
ALL DOWNWARD MOTION SATURDAY AND SATURDAY NIGHT. THE LOW LEVEL
WINDS ARE PROGGED TO GO TO UPSLOPE FRIDAY AFTERNOON AND EVENING.
MORE NORMAL DIURNAL PATTERNS ARE PROGGED FOR SATURDAY. FOR
MOISTURE...IN INCREASES SOMEWHAT FRIDAY...WITH THE BEST FRIDAY
EVENING OVER THE MOUNTAINS. MOISTURE DRIES OUT LATE FRIDAY
NIGHT...AND THERE ISN`T MUCH SATURDAY OR SATURDAY NIGHT. THE QPF
FIELDS SHOW A TINY AMOUNT OF MEASURABLE SNOWFALL OVER THE HIGH
MOUNTAINS FRIDAY EVENING...BUT ONLY ON THE GFS. WILL KEEP POPS IN
FRIDAY NIGHT...MOSTLY OVER JUST THE HIGH MOUNTAINS. FOR
TEMPERATURES...FRIDAY`S HIGHS ARE 2-4 C COOLER THAN TODAY`S.
SATURDAY`S ARE SIMILAR TO FRIDAY`S. FOR THE LATER DAYS...SUNDAY
THROUGH WEDNESDAY...MODELS KEEP MODERATE NORTHWESTERLY FLOW ALOFT
FOR THE CWA SUNDAY AND MONDAY. ON TUESDAY AND WEDNESDAY IT IS
WEST-NORTHWESTERLY AND INCREASES IN SPEED....ESPECIALLY ON THE
GFS. THE GFS BRINGS A JET MAXIMUM OVER THE CWA...THE ECMWF KEEPS
IT WELL NORTH AND NORTHEAST. MOISTURE IS LACKING ALL FOUR DAYS.
&&
.AVIATION...VFR TODAY AND TONIGHT. WINDS WILL BE LIGHT SLY THIS
MORNING AND MORE SSW AFTER SUNRISE. FOR THIS AFTN THERE MAY BE A
WK DENVER CYCLONE WITH WINDS BECOME MORE NNE AFTER 20Z. BY 00Z
WINDS MAY BECOME MORE ESE AND THEN BACK TO DRAINAGE BY 02Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....RJK
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS TAUNTON MA
702 AM EST THU DEC 12 2013
.SYNOPSIS...
MUCH COLDER THAN NORMAL CONDITIONS MOVE ACROSS THE REGION TODAY
AND FRIDAY AS TWO ARCTIC FRONTS PUSH THROUGH. THE FIRST FRONT
SWEEPS THROUGH THE REGION EARLY THIS MORNING AND THE OTHER MIDDAY
FRIDAY. BOTH ARCTIC FRONTS MAY BE ACCOMPANIED BY BRIEF SNOW
SQUALLS. A COASTAL STORM WILL LIKELY BRING ACCUMULATING SNOWFALL
TO THE REGION LATE SATURDAY INTO EARLY SUNDAY. DRIER BUT COLD
WEATHER FOLLOWS FOR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM UPDATE...
SUBTLE BUT ARCTIC FRONT MOVING ACROSS RI AND EASTERN MA EARLY
THIS MORNING WITH DEW PTS FALLING OFF INTO THE SINGLE DIGITS
BEHIND THE FRONT. EARLIER CLOUDS AND SNOW SQUALLS ASSOCIATED WITH
THE FRONT HAVE DISSIPATED. WATCHING AREA OF OCEAN EFFECT CLOUDS
FORMING OVER CAPE COD BAY AND MASS BAY AS ARCTIC AIRMASS STREAMS
ACROSS THE RELATIVELY WARM OCEAN WATERS. LATEST MESOSCALE MODELS
INCLUDING THE RAP13 AND HRRR KEEP ANY OCEAN EFFECT SNOWS WELL
OFFSHORE. THUS DRY WEATHER SHOULD PREVAIL ACROSS CAPE COD AND
NANTUCKET. PREVIOUS FORECAST CAPTURES THESE DETAILS NICELY SO NO
MAJOR CHANGES WITH THIS FORECAST UPDATE. EARLIER DISCUSSION BELOW.
==================================================================
LINE OF SNOW SHOWERS CONTINUES TO SLOWLY CROSS THE REGION AT 09Z
WITH -SN NOTED AT KORH. EXPECT LINE TO SLOWLY DISSIPATE AS IT
PUSHES S...BUT COULD DROP BRIEF SNOW SHOWERS ACROSS SOUTHERN AREAS
THROUGH 13Z-14Z.
ARCTIC FRONT WILL PUSH OFFSHORE BY 12Z AS DEWPTS HAVE DROPPED TO
THE SINGLE DIGITS ACROSS S NH ALREADY. EXPECT LINE OF CLOUDS
ASSOCIATED WITH THE SNOW SHOWERS TO PUSH OFFSHORE BY MID
MORNING. WILL SEE SOME MID AND HIGH CLOUDS CROSSING THE REGION
DURING THE DAY...BUT GENERALLY MOSTLY CLEAR SKIES EXCEPT ALONG THE
OUTER CAPE AND ISLANDS WHERE OCEAN EFFECT CLOUDS MAY DEVELOP AND
MOVE ONSHORE. MAY ALSO SEE SOME CLOUDS DRIFTING INTO SW NH/W MA
FROM THE LAKE EFFECT SNOW BANDS ACROSS NY STATE.
H925 TEMPS DROP TO -12C TO -15C BY EARLY AFTERNOON WITH VERY GOOD
MIXING ALLOWING NW WINDS TO PICK UP. EXPECT DAYTIME HIGHS ONLY IN
THE 20S...THOUGH MAY CRACK 30 ALONG THE IMMEDIATE S COAST. WITH
THE WIND...THOUGH...WIND CHILLS WILL RANGE FROM THE SINGLE DIGITS
OVER THE HIGHER TERRAIN OF S NH TO TEENS ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT...
SKIES WILL AVERAGE OUT PARTLY CLOUDY AS PATCHY MID AND HIGH CLOUDS
MOVE ACROSS. SOME LOWER CLOUD BANDS MAY CONTINUE TO PUSH INTO
WESTERN AREAS FROM NY STATE WITH CONTINUED LAKE EFFECT SNOWS. MID
LAYER CLOUDS WILL START TO INCREASE TOWARD DAYBREAK AHEAD OF NEXT
FRONT. ANOTHER VERY COLD NIGHT WITH LOWS IN THE TEENS...EXCEPT FOR
LOWER 20S ALONG THE IMMEDIATE COAST AND SOME SINGLE DIGITS OVER
THE HIGHER TERRAIN OF S NH.
FRIDAY...
EXPECT ANOTHER SHOT OF COLD AIR TO WORK OUT OF CANADA AS ANOTHER
SHORT WAVE/ARCTIC FRONT WORKS ACROSS THE REGION DURING THE DAY.
MODELS DO SHOW SOME MOISTURE WITH THIS SYSTEM AND...WITH TODAY/S
FRONT...COULD SEE ANOTHER BAND OF SNOW SHOWERS THOUGH WILL BE
TOUGH TO HOLD TOGETHER EXCEPT ACROSS SW NH/W MA ASSOCIATED WITH
LAKE EFFECT SNOW BANDS. HIGHS WILL BE IN THE MID 20S TO LOWER 30S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
HIGHLIGHTS...
*** ARCTIC COLD LINGERS INTO SAT ***
*** A PLOWABLE SNOWFALL REMAINS LIKELY SAT NGT/EARLY SUN ***
FRIDAY NIGHT...
A SECOND ARCTIC FRONT SLIPS SOUTH OF THE REGION FRI AFTN WITH A
REINFORCING SURGE OF POLAR AIR INTO SOUTHERN NEW ENGLAND. THIS SETS
THE STAGE FOR A ROUND OF WINTRY WEATHER LATE SAT INTO EARLY SUNDAY.
SAT/SUN...
00Z MODEL GUIDANCE HAS TRENDED TOWARD THE NORTHERN AND SOUTHERN
STREAMS REMAINING SEPARATE/UNPHASED REGARDING THE POTENTIAL EAST
COAST CYCLOGENESIS THIS WEEKEND. THERE IS GOOD MODEL AGREEMENT THAT
THE SOUTHERN STREAM SHORT WAVE WILL BECOME QUITE SHEARED AS IT
ENTERS THE COLD CONFLUENT FLOW ACROSS THE NORTHEAST. THIS RESULTS IN
A WEAKER SURFACE WAVE WITH LESS QPF...BUT ALSO A COLDER SOLUTION AS
SURFACE WAVE TRACKS FARTHER OFFSHORE WITH WEAKER THERMAL ADVECTION
INTO SOUTHERN NEW ENGLAND. THE GEFS MEAN TRACKS THE SURFACE LOW NEAR
NANTUCKET...WHILE THE 51 ENSEMBLE MEMBER OF THE ECENS TRACKS THE
SURFACE WAVE CLOSER TO THE 40N/70W BENCHMARK. THIS IS A SOUTHEAST
TREND FROM PREVIOUS RUNS. THE DETERMINISTIC 00Z GFS/ECMWF AND UKMET
ARE JUST ABOUT OVER THE BENCHMARK 12Z SUNDAY. THUS ALL MODEL
GUIDANCE HAS TRENDED WEAKER AND FARTHER OFFSHORE. THIS EVENT IS
STILL 2 DAYS AWAY SO NEW TRENDS ARE POSSIBLE. HOWEVER THINK ITS
PRUDENT TO RECOGNIZE THIS MAJOR SHIFT IN THE GUIDANCE AND TREND THE
FORECAST TOWARD LESS QPF AND SOMEWHAT COLDER.
AS FOR MODEL GUIDANCE...THE 00Z NAM WAS DISCARDED AS A NORTHERN
OUTLIER WITH ITS SURFACE LOW/CYCLONE TRACKING ALONG THE COASTAL
PLAIN OF SOUTHERN NEW ENGLAND. AS MENTIONED ABOVE THE CONSENSUS
TRACK /INCLUDING THE 51 MEMBER ECENS ENSEMBLE MEAN/ IS NOW CLOSER TO
THE 40N/70W BENCHMARK. THUS WILL BASE THIS FORECAST ON AN EVEN BLEND
OF 00Z GFS/ECMWF.
TIMING...AT THIS TIME RANGE PRECIP LOOKS TO ARRIVE SOMETIME SAT AFTN
WITH THE HEAVIEST PRECIP OCCURRING SAT NIGHT BEFORE TAPERING OFF SUN
MORNING.
QPF...WITH MODELS TRENDING TOWARD A MORE SHEARED LOW MODEL QPF
CONSENSUS (50/50 BLEND OF GFS/EC) IS LESS THAN PREVIOUS RUNS WITH
TOTAL QPF RANGING FROM 0.60 TO 0.80 INCHES.
PTYPE...GIVEN RECENT TRENDS TOWARD A WEAKER COASTAL LOW AND FARTHER
OFFSHORE TRACK...THE PROBABILITY OF A COLDER SOLUTION HAS INCREASED.
THIS TREND LEANS TOWARD MAINLY SNOW FOR MUCH OF SOUTHERN NEW ENGLAND
WITH MIXED PRECIP POSSIBLY AS FAR NORTHWARD INTO NORTHEAST
CT/NORTHERN RI AND THE GREATER BOSTON AREA. THIS IS TYPICAL FOR A
COASTAL LOW PASSING NEAR THE BENCHMARK. HOWEVER THE MIXED PRECIP
LINE MAY BE HELD FARTHER SOUTH GIVEN THE STRONG ARCTIC HIGH OVER
QUEBEC COMBINED WITH POSSIBLE COASTAL FRONT DEVELOPMENT IN RI AND
EASTERN-SOUTHEASTERN MA.
SNOWFALL POTENTIAL...THIS EVENT IS STILL 2 DAYS AWAY AND THE COASTAL
STORM HASN/T FORMED YET. THUS OUR PRELIMINARY SNOWFALL FORECAST IS
FOR THE POTENTIAL OF UP TO 6 INCHES OF SNOWFALL FOR MUCH OF THE
REGION...WITH POSSIBLY LESS ALONG THE SOUTH COAST INCLUDING CAPE COD
AND THE ISLANDS AS MIXED PRECIP MAY ENTER THIS REGION. COLD AIRMASS
AT THE ONSET MAY YIELD GREATER THAN A 10/1 SNOW TO LIQUID RATIOS.
THIS COMBINED WITH ANY MID LEVEL BANDING POTENTIAL INTRODUCES A LOW
RISK OF 6+ INCHES POSSIBLE. REGARDLESS OF EXACT SNOWFALL NUMBERS
THERE WILL BE SUFFICIENT SNOW AND POSSIBLY MIXED PRECIP TO HAVE A
SIGNIFICANT IMPACT ON TRAVEL WITH TREACHEROUS ROAD CONDITIONS LATE
SAT INTO EARLY SUNDAY.
UNCERTAINTY...AS MENTIONED ABOVE THIS POTENTIAL EVENT IS STILL 2
DAYS AWAY AND THE STORM HASN/T FORMED YET. THUS ADDITIONAL FORECAST
CHANGES ARE LIKELY AS WE NEAR THE EVENT. ONE POSSIBLE OUTCOME WE
WILL HAVE TO BE ON GUARD FOR IS THE POTENTIAL FOR EVEN A
WEAKER/SHEARED SURFACE LOW YIELDING LESS QPF AND TRACKING FARTHER
OFFSHORE. THIS WOULD ALSO SHIFT THE RAIN/SNOW LINE FARTHER
SOUTHEAST ALONG WITH AXIS OF HEAVIEST SNOWFALL.
MON/TUE/WED...LOOKS FAIRLY QUIET BUT COLD /ALTHOUGH NOT AS COLD AS
TODAY AND FRI/ WITH LONG WAVE TROUGH AND ASSOCIATED BELOW NORMAL
HEIGHTS LINGERING ACROSS THE NORTHEAST.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
7 AM UPDATE...
NO MAJOR CHANGES TO 12Z TAFS. HIGH CONFIDENCE FOR VFR AND DRY
WEATHER TODAY. EARLIER DISCUSSION BELOW.
================================================================
TODAY-TONIGHT...VFR CONDITIONS. MAY SEE LOCAL MVFR CIGS ACROSS
OUTER CAPE COD AND NANTUCKET WITH OCEAN EFFECT CLOUDS. LOW PROB OF
SNOW SHOWERS LATE TODAY AND TONIGHT FROM KACK-KMVY AND OUTER CAPE
COD.
FRIDAY...MAINLY VFR CONDITIONS. WINDS SHIFT TO N WITH ANOTHER SHOT
OF COLDER AIR. LOW PROB OF MVFR CIGS ALONG COAST...ESPECIALLY CAPE
COD AND THE ISLANDS.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
MODERATE TO HIGH CONFIDENCE.
IFR-LIFR CIGS/VSBYS SAT AND SUN IN SNOW POSSIBLY MIXING WITH
SLEET/FREEZING RAIN AND/OR ALONG THE SOUTH COAST INCLUDING CAPE
COD AND THE ISLANDS. UP TO 6 INCHES OF SNOWFALL POSSIBLE WITH LESS
ALONG SOUTH COAST. INCREASING EAST-NORTHEAST WINDS FOR COASTAL
TERMINALS WITH NORTHERLY FLOW THROUGH THE INTERIOR. CONDITIONS
IMPROVE INTO SUNDAY AS WINDS BACK WEST-NORTHWESTERLY BECOMING
BLUSTERY.
MONDAY...MODERATE CONFIDENCE FOR VFR AND MAINLY DRY WEATHER.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
TODAY...EXPECT W-NW WINDS TO GUST UP TO 20-25 KT EARLY...THEN WILL
DIMINISH BY MIDDAY. HOWEVER...SEAS ON THE OUTER WATERS WILL REMAIN
ABOVE 5 FT SO HAVE KEPT SMALL CRAFT GOING THERE. MAY SEE REDUCED
VSBYS IN OCEAN EFFECT SNOW SHOWERS.
TONIGHT...NW WINDS WILL PICK UP AGAIN ACROSS THE WATERS SO HAVE
SMALL CRAFTS UP FOR ALL WATERS. THERE IS A LOW CHANCE FOR GALE
GUSTS TOWARD DAYBREAK OVER THE OUTER WATERS E AND S OF NANTUCKET.
LIGHT FREEZING SPRAY LIKELY LATE NEAR NANTUCKET. OCEAN EFFECT SNOW
SHOWERS WILL LOWER VSBYS.
FRIDAY...W WINDS WILL CONTINUE TO GUST UP TO 25-30 KT...SHIFTING
BACK TO NW WITH ANOTHER COLD FRONTAL PASSAGE. CONTINUED LOW
CHANCE OF GALE GUSTS E AND S OF NANTUCKET THROUGH MIDDAY. LIGHT
FREEZING SPRAY LIKELY NEAR NANTUCKET. OCEAN EFFECT SNOW SHOWERS
CONTINUE WITH REDUCED VSBYS.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...MODERATE CONFIDENCE.
COASTAL LOW EXITS MID ATLC STATES AND TRACKS NEAR THE 40N/70W
BENCHMARK SUNDAY MORNING. LOW TO MODERATE PROBABILITY FOR EAST-
NORTHEAST GALES. LOW RACES OUT TO SEA LATER SUN FOLLOWED BY GUSTY NW
WINDS LATER SUN INTO MON.
&&
.TIDES/COASTAL FLOODING...
THE RISK FOR COASTAL FLOODING APPEARS LOWER THAN EARLIER THOUGHT.
COASTAL STORM LATE SAT INTO SUN WILL NOT BE AS STRONG AS EARLIER
PREDICTED. HOWEVER ARCTIC HIGH PRES OVER QUEBEC WILL COMBINE WITH
THE WEAKER COASTAL LOW FOR A PERIOD OF STRONG ONSHORE WINDS ALONG
WITH A MODEST STORM SURGE AND WAVE ACTION OFFSHORE. ASTRONOMICAL
TIDES ARE FAIRLY LOW. FOR EXAMPLE ASTRO TIDES AT BOSTON SUN
MORNING ARE AROUND 10.3 FT. A STORM SURGE OF 1.0 FT TO 1.5 FT IS
EXPECTED WITH A LOW PROBABILITY OF SURGE VALUES NEAR 2 FT ALONG
WITH WAVES 10-15 FT OFF THE EASTERN MA COASTLINE. THIS WILL LIKELY
FALL SHORT OF PRODUCING COASTAL FLOODING FOR THE EASTERN MA
COASTLINE. HOWEVER THIS EVENT IS STILL 2 DAYS AWAY AND STORM
INTENSITY AND TRACK CAN CHANGE. THEREFORE THE WORST CASE SCENARIO
APPEARS TO BE A LOW RISK OF MINOR COASTAL FLOODING FOR THE SUN
MORNING HIGH TIDE ALONG THE EASTERN MA COASTLINE. THE MORE LIKELY
SCENARIO IS FOR NO COASTAL FLOODING.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 5 PM EST FRIDAY
FOR ANZ231-232-235-237-251.
SMALL CRAFT ADVISORY FROM 1 AM TO 5 PM EST FRIDAY FOR ANZ230-
233-234-236.
SMALL CRAFT ADVISORY UNTIL 5 PM EST FRIDAY FOR ANZ250-254>256.
&&
$$
SYNOPSIS...NOCERA/EVT
NEAR TERM...NOCERA/EVT
SHORT TERM...EVT
LONG TERM...NOCERA
AVIATION...NOCERA/EVT
MARINE...NOCERA/EVT
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
355 AM EST THU DEC 12 2013
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A MID/UPPER LEVEL PATTERN
CHARACTERIZED BY A REX BLOCK STRUCTURE OVER THE PACIFIC COAST...
FOLLOWED DOWNSTREAM BY CONVERGENT FLOW FROM EITHER SIDE OF THIS
BLOCK COMING TOGETHER OVER THE CENTRAL PLAINS TO RESULT IN SOUTHERN
STREAM ZONAL FLOW ALONG THE NORTHERN GULF COAST AND BROAD LONGWAVE
NORTHERN STREAM TROUGHING OVER MUCH OF THE EASTERN HALF OF THE
NATION. OUR FORECAST AREA NOW RESIDES WITHIN THIS MAINLY WESTERLY
ZONAL FLOW ALOFT...AND THIS WAS SAMPLED WELL ABOVE 700MB ON THE
12/00Z KTBW SOUNDING PROFILE. ONE WEAK SHORTWAVE PROGRESSING DOWN
THE BACKSIDE OF THE TROUGH AND CLEARLY DEFINED WITH
DRYING/SUBSIDENCE OVER OKLAHOMA WILL QUICKLY TRANSLATE SOUTHEASTWARD
TOWARD THE REGION LATER TODAY AND TONIGHT AND HELP TO SCOUR OUT EVEN
MORE OF OUR MOISTURE ALOFT. WITHIN THE MAIN LONGWAVE TROUGH THIS
PATTERN CURRENTLY IS RESULTING IN A COLD FORECAST FOR MUCH OF THE
EASTERN CONUS...BUT ALSO GENERALLY BENIGN WEATHER WITH A BROAD
EXPANSE OF SURFACE HIGH PRESSURE OVER MS/OH/TN VALLEYS AND NO
SIGNIFICANT FORCING ALOFT.
THIS QUIET PATTERN WILL NOT LAST ALL THAT LONG THROUGH AS THE
CUT-OFF LOW NEAR THE BAJA REGION/SOUTHERN CALIFORNIA IS PROGGED TO
OPEN UP AND BECOME PROGRESSIVE WITHIN THE SOUTHERN STREAM FLOW ON
FRIDAY.
NEAR AT THE SURFACE...NORTHEAST FLOW AND ABUNDANT BOUNDARY LAYER
MOISTURE HAS ALLOWED THE DEVELOPMENT OF A LARGE EXPANSE OF LOWER
STRATUS FROM THE I-4 CORRIDOR NORTHWARD. THE SREF AND NARRE GUIDANCE
HAS BEEN HANDLING THIS STRATUS VERY WELL OVERNIGHT AND USED THESE
SOLUTIONS FOR CLOUD COVER THROUGH THE MORNING HOURS. AS MENTIONED
ABOVE...A LARGE EXPANSE OF 1030MB+ HIGH PRESSURE IS CENTERED TO OUR
NORTHWEST NEAR THE MIDDLE MS VALLEY. A WEAK AND NOW QUASI-STATIONARY
COLD FRONT IS CURRENTLY SITUATED TO THE SOUTH OF THE I-4 CORRIDOR
DOWN TOWARD CHARLOTTE AND LEE COUNTIES. THE APPROACH AND MASS FIELDS
PUSH ASSOCIATED WITH THE WEAK SHORTWAVE ARRIVING LATER TODAY WILL
HELP TO FINALLY "SHOVE" THIS BOUNDARY WELL TO THE SOUTH OF OUR
ZONES.
&&
.SHORT TERM (TODAY THROUGH SATURDAY)...
TODAY AND TONIGHT...
AREAS OF LOW STRATUS OVER THE NORTHERN AND CENTRAL ZONES SHOULD MOVE
AND ERODE SOUTHWARD AS DRIER AIR BEGINS TO QUICKLY FILTER IN FROM
THE NORTH DURING THE MORNING HOURS. THEREFORE AREAS OF MOSTLY CLOUDY
SKIES TO START THE DAY SHOULD SCATTER OUT FOR THE SECOND HALF OF THE
DAY. THE MOST ABUNDANT CLOUD POTENTIAL FOR THE AFTERNOON SHOULD BE
SOUTH OF TAMPA BAY. AS WEAK SHORTWAVE ENERGY APPROACHES AND PASSES
THROUGH THE REGION TODAY...THE COOLER AND DRIER AIRMASS BEHIND THE
COLD FRONT WILL FINALLY BEGIN TO ARRIVE. HIGH TEMPERATURES TODAY
WILL RANGE FROM THE UPPER 60S FOR LEVY COUNTY TO THE LOWER/MID 70S
AROUND I-4...AND MID TO UPPER 70S FURTHER SOUTH. THE LOW LEVEL
MOISTURE WILL STILL BE IN PLACE LATE THIS MORNING AND EARLY
AFTERNOON AROUND HIGHLANDS COUNTY...AND WITH DEVELOPING NORTHEAST
FLOW...A SPEED CONVERGENCE SPRINKLES OR 2 IS POSSIBLE...BUT
MEASURABLE RAINFALL IS REALLY NOT EXPECTED.
A DRY COLUMN DESCENDS UPON THE REGION OVERNIGHT AS THE RIDGE OF HIGH
PRESSURE PASSES THROUGH GA AND THE CAROLINAS. IT WILL BE A
NOTICEABLY COOLER NIGHT THAN WHAT WE HAVE EXPERIENCED LATELY. THE
RIDGE IS TOO FAR NORTH FOR ANY REAL DE-COUPLING OF THE BOUNDARY
LAYER AND EFFICIENT RADIATIONAL COOLING FOR MOST OF THE REGION...BUT
STILL EXPECTING MANY SPOTS NORTH OF I-4 TO DROP INTO THE 40S WITH
UPPER 40S TO LOW 50S COMMON FURTHER SOUTH. THE COLDEST TEMPS WILL BE
UP TOWARD LEVY COUNTY WHERE THE CLOSEST PROXIMITY TO THE RIDGE AND
GOOD DRAINAGE SETUP SHOULD ALLOW TEMPERATURES TO DROP INTO THE
MID/UPPER 30S. AS OF RIGHT NOW...DO NOT EXPECT ANY SUB-FREEZING
TEMPERATURES...HOWEVER...IF WINDS CAN GO CALM FOR A FEW HOURS AROUND
SUNRISE...THEN THERE WILL BE THE THREAT OF PATCHY FROST. HAVE ADDED
PATCHY FROST TO THE FORECAST FOR ALL AREAS FORECAST TO REACH 36
DEGREES OR BELOW FOR THE FEW HOURS SURROUNDING SUNRISE.
FRIDAY/FRIDAY NIGHT...
FRIDAY IS SHAPING UP TO BE A VERY PLEASANT END TO THE WORK WEEK AS
OUR LOW LEVEL FLOW BECOMES EASTERLY UNDERNEATH A ZONAL FLOW
PATTERN ALOFT. OUR NEXT SYSTEM FOR THE WEEKEND WILL STILL BE WELL TO
OUR WEST OVER THE SOUTHERN PLAINS. WITH A DRY COLUMN AND LITTLE TO
NO SYNOPTIC FORCING TO SPEAK OF...WILL SHOW A RAIN FREE FORECAST.
WITH THE EASTERLY FLOW DELVING SOME ATLANTIC MOISTURE...WOULD
ANTICIPATE MOSTLY CLEAR SKIES GIVING WAY TO A SCT-BKN FAIR WEATHER
CUMULUS FIELD DURING THE AFTERNOON. ENOUGH MOISTURE RETURN WILL
HAVE OCCURRED BY FRIDAY NIGHT TO RESULT IN A MUCH WARMER FORECAST
THAN THURSDAY NIGHT. MOST LOCATIONS SHOULD STAY IN THE UPPER 50S TO
LOWER 60S...WITH SOME COOLER LOWER TO MIDDLE 50S FOR OUR NORTHERN
NATURE COAST ZONES.
SATURDAY...
OVERALL A WARM AND GENERALLY DRY DAY EXPECTED FOR THE FIRST HALF OF
THE UPCOMING WEEKEND. SHORTWAVE ENERGY WILL EJECT EASTWARD ACROSS
THE TN VALLEY DRAGGING A WEAK WAVE LOW LOW PRESSURE NORTHWARD FROM
THE CENTRAL GULF COAST. A COLD FRONT WILL EXTEND SOUTH FROM THIS
FEATURE INTO THE CENTRAL GULF...BUT ONLY MOVE SLOWLY EASTWARD
THROUGH THE DAY. THROUGH THE DAYLIGHT HOURS OF SATURDAY...OUR REGION
SIMPLY REMAINS AHEAD OF ANY RESPECTABLE SYNOPTIC FORCING AND UNDER
UNFAVORABLE UPPER JET PLACEMENT. AS THE FRONT SLOWLY DRAGS
EASTWARD...HAVE KEPT A CHANCE FOR A FEW SHOWER OR A THUNDERSTORM UP
TOWARD LEVY COUNTY LATE IN THE AFTERNOON...BUT EVEN THIS MAY BE
AGGRESSIVE ON THE TIMING. ELSEWHERE...OTHER THAN A BRIEF INSTABILITY
SHOWER...THE FORECAST IS DRY WITH ABOVE NORMAL TEMPERATURES. THIS
FRONT EVEN BEYOND SATURDAY DOES NOT LOOK TO BE MUCH OF A RAIN
PRODUCER OTHER THAN FOR OUR FAR NORTHERN ZONES. BY SATURDAY
NIGHT...THE MAIN ENERGY ASSOCIATED WITH THE UPPER IMPULSE WILL BE
SHIFTING TO NEW CYCLOGENESIS ALONG THE MID-ATLANTIC BAROCLINIC ZONE.
THIS TRANSLATION OF ENERGY AWAY FOR THE FL PENINSULA IS A COMMON
OCCURRENCE DURING THE COOL SEASON. THE RESULT FOR OUR REGION IS A
REDISTRIBUTION OF THE SYNOPTIC FORCING TO THE NORTH AND A STRETCHING
(LESS FOCUS) OF THE TRAILING FRONTAL FEATURE. THE DECREASE OF ALL
THE FORCING RESULTS IN AN UNORGANIZED OR BROKEN BAND OF GENERALLY
UNIMPRESSIVE CONVECTION ALONG THE FRONT FOR SATURDAY NIGHT INTO
SUNDAY.
&&
.LONG TERM (SUNDAY THROUGH NEXT THURSDAY)...
A BROAD UPPER LEVEL TROUGH FROM THE GREAT LAKES TO THE SOUTHERN
PLAINS SLOWLY MOVES TO THE EASTERN SEABOARD BY MON WITH THE FLOW
ALOFT VEERING FROM SOUTHWEST TO WEST-NORTHWEST. AT THE SURFACE A LOW
ON THE CENTRAL GULF COAST...WITH A COLD FRONT TRAILING BACK ACROSS
THE WESTERN GULF...TRACKS TO THE NORTHEAST. THE LOW REACHES THE
COASTAL WATERS OF THE CANADIAN MARITIMES MON AS THE FRONT SLIDES
ACROSS THE GULF AND INTO SOUTH FL.
FOR TUE-WED...THE BROAD TROUGH CONTINUES OVER THE EASTERN STATES AS
A SHORT WAVE TROUGH DROP OUT OF CENTRAL CANADA TO THE GREAT LAKES
REGION. THE FRONT LINGERS OVER OR JUST SOUTH OF SOUTH FL AS HIGH
PRESSURE IN THE SOUTHERN PLAINS AND WESTERN GULF MOVES ACROSS THE
GULF COAST TO THE SE U.S. WHERE IT WEAKENS...ALLOWING MOISTURE FROM
THE FRONT TO CREEP BACK NORTH INTO FL.
THE BEST ODDS OF RAINFALL WILL BE SAT NIGHT WITH LIKELY-CHANCE-
SLIGHT CHANCE SHOWERS AND STORMS...WITH THE HIGHEST POPS IN THE
NORTH. THEN DURING SUN THE GULF COAST LOW MOVES AWAY AND THE FRONT
APPROACHES WITH CHANCE SHOWERS/STORMS. THESE THEN TAPER DOWN TO JUST
SLIGHT CHANCE SHOWERS/STORMS SUN NIGHT-MON NIGHT...GRADUALLY ENDING
FROM NORTHWEST TO SOUTHEAST. MOISTURE INCREASING FROM THE SOUTH WILL
BRING A SLIGHT CHANCE OF SHOWER WED. TEMPERATURES INITIALLY ABOVE
NORMAL SUN WILL DRIP BELOW FOR THE EARLY PART OF THE WEEK THEN WARM
TO NEAR NORMAL BY WED.
&&
.MARINE...
STRONG HIGH PRESSURE BUILDING TO THE NORTH OF THE EASTERN GULF OF
MEXICO WILL TIGHTEN THE PRESSURE GRADIENT ENOUGH TO ALLOW FOR
PERIODS OF ADVISORY LEVEL WINDS TODAY AND TONIGHT. THE GREATEST
COVERAGE OF THESE ELEVATED WINDS WILL OCCUR FROM LATE THIS AFTERNOON
THROUGH TONIGHT...AND THEN FALL BELOW ADVISORY LEVELS FOR ALL ZONES
FRIDAY MORNING. WINDS WILL THEN SHIFT EASTERLY AND EVENTUALLY
SOUTHEASTERLY BY SATURDAY MORNING AHEAD OF THE NEXT COLD FRONT THAT
IS SCHEDULED TO CROSS THE FORECAST WATERS ON SUNDAY.
&&
.AVIATION...
A WEAKENING BOUNDARY EASING SOUTH WILL BRING PREVAILING MVFR VSBY OR
CIGS...THROUGH 12/15Z IN THE NORTH AND 12/18Z IN THE SOUTH. EXPECT
TEMPO IFR MAINLY CIGS AT TERMINALS NORTH OF THE BOUNDARY UNTIL
SHORTLY AFTER SUNRISE. LIGHT NORTHERLY WINDS BECOME NORTH-NORTHEAST
AND INCREASE SOME DURING THE DAY.
&&
.FIRE WEATHER...
DRIER AIR WILL FILTER INTO THE REGION FROM THE NORTH BEHIND A
DEPARTING FRONT DURING TODAY. THE DRIER AIR WILL ALLOW RELATIVE
HUMIDITY LEVELS TO FALL BELOW CRITICAL LEVELS FROM PASCO COUNTY
NORTHWARD THROUGH THE NATURE COAST. PORTIONS OF LEVY AND CITRUS
COUNTIES SHOULD SEE 3-5 HOURS OF THESE CRITICAL RELATIVE HUMIDITY
LEVELS. ELSEWHERE...DRIER AIR WILL FILTER SOUTH...BUT CRITICAL
CONDITIONS ARE NOT ANTICIPATED. DESPITE THE LOW RELATIVE HUMIDITY
LEVELS OVER THE NATURE COAST...WINDS WILL REMAIN BELOW CRITICAL
LEVELS AND CURRENT ERC VALUES ARE BELOW 25. EASTERLY WINDS ON FRIDAY
AND THEN SOUTHEAST WINDS ON SATURDAY WILL INCREASE THE MOISTURE ONCE
AGAIN AND NO FIRE WEATHER CONCERNS ARE ANTICIPATED FOR THE END OF
THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 52 76 63 / 10 0 0 10
FMY 79 56 80 64 / 10 0 10 10
GIF 74 48 75 59 / 10 10 10 10
SRQ 77 52 78 63 / 10 0 0 10
BKV 72 43 75 57 / 10 10 10 10
SPG 72 55 74 65 / 10 0 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO
7 AM EST FRIDAY FOR BONITA BEACH TO ENGLEWOOD OUT 20 NM
-BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD TO
TARPON SPRINGS OUT 20 NM.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 AM EST
FRIDAY FOR ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60
NM-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
858 PM CST FRI DEC 13 2013
.DISCUSSION...
830 PM CST
NO BIG UPDATES TO GOING FORECAST WITH ALSO NO CHANGES TO CURRENT
HEADLINES IN PLACE.
LONGWAVE TROUGH CONTINUES TO SHIFT EAST THROUGH THE CENTRAL
CONUS...WITH SEVERAL LEAD WAVES LIFTING NORTHEAST OUT AHEAD OF IT.
ASSOCIATED FORCING AS WELL AS A GOOD WAA PUSH ALLOWED FOR LIGHT TO
MODERATE SNOW TO QUICKLY MOVE INTO AREAS SOUTH OF I-80 EARLY THIS
EVENING. HIGH AMOUNTS OF MOISTURE WERE PRESENT ON THE 00Z ILX
RAOB...WITH 0.74 INCH PWAT AND 4G/KG MIXING RATIO AT 700MB.
LOW/MID LEVEL CONVERGENCE OWING TO MID/LOW LEVEL BAROCLINIC ZONE
STRETCHED ACROSS NORTH CENTRAL ILLINOIS HAS ALSO AIDED IN THE
DEVELOPMENT OF SEVERAL SMALLER SCALE FEATURES OVER THE LAST HOUR.
THE VISIBILITY HAS GENERALLY STAYED IN THE 1-3SM RANGE...WHILE
FALLING UNDER ONE MILE IN THESE SMALLER HEAVIER BANDS. ALTHOUGH
THESE SMALLER FEATURES WILL LIKELY REMAIN OVER THE NEXT SEVERAL
HOURS...THEY HAVE REMAINED TRANSIENT WITH LOCATIONS ONLY OBSERVING
BRIEF PERIODS OF THIS HEAVIER SNOW.
EXPECT THIS LIGHT TO MODERATE SNOW TO SLOWLY LIFT NORTH WITH THE
I-88 CORRIDOR LIKELY OBSERVING SNOWFALL BY THE 930 PM CST TIME
FRAME. ALTHOUGH STRONGEST WAA APPEARS TO SHIFT TO THE EAST OF THE
CWA OVER THE NEXT SEVERAL HOURS...BROAD SCALE LIFT AS WELL AS
INCREASE IN LOW LEVEL FRONTOGENESIS IS EXPECTED TO HELP PERSIST
LIGHT/MODERATE SNOW AND EVEN PROVIDE BRIEF PERIODS OF HEAVIER
SNOW. THE STRONGEST MESOSCALE FORCING WILL PERSIST TONIGHT AND
REMAIN IN THE ADVISORY AND WARNING AREAS TONIGHT INTO SATURDAY
MORNING. HAD DEBATED ADDING LIVINGSTON/KANKAKEE/LAKE IN/PORTER
COUNTY IN THE WARNING...WITH THIS ANTICIPATED STRONGER FORCING.
ALTHOUGH...WITH ONLY AN ADDITIONAL INCH OR TWO TO THE GOING
TOTALS...HAVE DECIDED TO LEAVE THE ADVISORY GOING AND INSTEAD
INCREASE THE SNOW RANGE TO 4-7 INCHES. REST OF THE SNOW TOTALS IN
THE HEADLINES STILL APPEAR TO BE ON TRACK...WITH 5 TO 8 INCHES
STILL LIKELY IN THE WARNING AREA.
CONTINUE TO MONITOR A SEPARATE AREA OF DEVELOPING SNOW ACROSS
SOUTHERN WISCONSIN AND FAR NORTHERN ILLINOIS. OUTSIDE OF THE LAKE
EFFECT/ENHANCEMENT EXPECTED ACROSS THIS AREA...LATEST GUIDANCE
CONTINUES TO INDICATE ANOTHER AREA OF BETTER FRONTOGENITICAL
FORCING ACROSS SOUTHERN WISCONSIN. THIS FORCING COULD ACT TO
SLIGHTLY ENHANCE TOTALS MORE TOWARDS THE ILLINOIS/WISCONSIN
BORDER...WITH MAYBE MORE 1-3 INCHES COULD BE OBSERVED BY TOMORROW
MORNING. LAKE EFFECT/ENHANCEMENT FOR FAR NORTHEAST ILLINOIS HAS
SHOWN INCREASING TRENDS WITH LATEST GUIDANCE. ALTHOUGH NOT OVERLY
LARGE...THIS WAS ENOUGH TO INCREASE SNOW TOTALS SLIGHTLY. LOW
LEVEL CONVERGENCE INCREASES TOWARDS EARLY SATURDAY MORNING...AND
POSSIBLY LINGERS INTO SATURDAY AFTERNOON AS BOUNDARY LAYER FLOW
SLOWLY SHIFTS. WITH THIS POSSIBLY PROVIDING AN EXTENDED PERIOD OF
LIGHT SNOW...HAVE INCREASED SNOW TOTALS MORE TOWARDS 1-3 IN LAKE
IL...BUT HAVE STILL LEFT OUT OF THE ADVISORY AT THIS TIME.
ALTHOUGH AN ISOLATED 4 INCH REPORT CANNOT BE RULED OUT IN THIS
AREA...WAS NOT ENOUGH TO INCLUDE IN THE HEADLINE. ONCE AGAIN...THE
EXTENDED NATURE OF THIS LIGHT LAKE EFFECT SNOW COULD WARRANT
HIGHER TOTALS IN LAKE COUNTY IL AND POSSIBLY HEADLINE CHANGES
SATURDAY MORNING.
RODRIGUEZ
//PREV DISCUSSION...
319 PM CST
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...
NOT MUCH HAS CHANGED WITH THE CURRENT THINKING FOR TONIGHT AND
SATURDAY REGARDING SNOWFALL AMOUNTS AND PLACEMENT. THE CURRENT
WATER VAPOR IMAGERY CONTINUES TO INDICATE A DECENT DISTURBANCE
NEAR THE TEXAS PANHANDLE EARLY THIS AFTERNOON...WITH SEVERAL LEAD
DISTURBANCES ACROSS OK AND INTO WESTERN MO. PROFILER AND VWP DATA
ACROSS THE SOUTHERN PLAINS AND MID MISSISSIPPI VALLEY INDICATES
THAT AROUND 30KT OF SOUTHWESTERLY FLOW AROUND 850 MB HAS DEVELOPED
IN ASSOCIATION WITH THIS SYSTEM. THIS IS ALLOWING FOR SOME DECENT
MOISTURE TRANSPORT AND ISENTROPIC ASCENT ACROSS THE MISSOURI AND
WEST CENTRAL ILLINOIS THIS AFTERNOON. THIS HAS PRODUCED A GOOD
AREA OF PRECIPITATION ACROSS MISSOURI...ESPECIALLY ALONG THE
LEADING EDGE OF THE BETTER MOISTURE TRANSPORT.
I EXPECT THIS AREA OF PRECIP TO CONTINUE TO MOVE NORTHWARD AND TO
OVERSPREAD MOST AREAS ALONG AND SOUTH OF INTERSTATE 80 THROUGH THE
EVENING AS THE BETTER MOISTURE GETS DRAWN NORTHWARD IN ASSOCIATION
WITH THE APPROACHING SOUTHERN STREAM SYSTEM. IT APPEARS LIKELY THAT
A BAND OF MODERATE TO HEAVY SNOW WILL SET UP THIS EVENING ACROSS MY
SOUTHERN COUNTIES...IN ASSOCIATION WITH A DEVELOPING BAND OF
FRONTOGENESIS. THE ENHANCED FORCING FOR ASCENT WITHIN THE
FRONTOGENETIC CIRCULATION WILL ALLOW FOR SOME DECENT ASCENT WITHIN
THE DENDRITIC GROWTH ZONE. THIS ALONG WITH THE FACT THAT STEEP LAPSE
RATES AND -EPV EXITS WITHIN AND ABOVE THIS ZONE ALSO SUGGESTS THAT
THEIR WILL BE SOME FAIRLY EFFICIENT SNOWFALL PRODUCTION WITHIN THIS
BAND OF SNOW. WITH THIS IN MIND...IT APPEARS THAT SNOWFALL RATES
COULD APPROACH 1 INCH PER HOUR FOR A COUPLE HOUR PERIOD THIS
EVENING...ESPECIALLY TO THE SOUTH OF INTERSTATE 80 WITHIN AND NEAR
THE CURRENT WINTER STORM WARNING.
A SECOND AREA OF SNOW WILL BE FAVORED...MAINLY ACROSS SOUTHERN
WISCONSIN THIS EVENING AS A SECONDARY AXIS OF FRONTOGENESIS DEVELOPS
ALONG A BAROCLINIC RIBBON...AND COMBINES WITH INCREASING FLOW AND LOW
LEVEL CONVERGENCE OFF OF LAKE MICHIGAN. HOWEVER...MOST HIGH RES
GUIDANCE CONTINUES TO FAVOR AREAS NORTH OF THE ILLINOIS BOARDER.
THEREFORE...IT APPEARS MOST OF NORTHERN ILLINOIS WILL REMAIN SNOW
FREE...THROUGH AT LEAST MID TO LATE EVENING.
THE SNOW SHOULD BEGIN TO SPREAD NORTHWARD BY LATE THIS EVENING...AND
BEGIN IMPACTING MOST OF NORTHERN ILLINOIS BY OR SHORTLY AFTER
MIDNIGHT AS THE SURFACE INVERTED TROUGH BECOMES ORIENTED NORTH TO
SOUTH ACROSS THE AREA OVERNIGHT. THE SNOW WILL CONTINUE INTO
SATURDAY AS SOME LARGER SCALE SUPPORT FOR ASCENT OVERSPREADS THE
AREA IN ASSOCIATION WITH THE APPROACHING NORTHERN STREAM SHORT WAVE.
THIS COULD EVEN LEAD TO A BIT IN AN UPTICK TO THE SNOWFALL
INTENSITY...PARTICULARLY ACROSS EASTERN ILLINOIS AND NORTHWESTERN
INDIANA...WHERE MID LEVEL DEFORMATION WILL CONTINUE IN ASSOCIATION
WITH THE MID LEVEL CIRCULATION. THE SNOW WILL GRADUALLY END ACROSS
NORTHERN ILLINOIS AS THE FLOW TURNS NORTHWESTERLY. SOME LINGERING
LAKE EFFECT SNOW SHOWERS ARE POSSIBLE ACROSS NORTHWESTERN INDIANA
INTO SATURDAY EVENING.
THERE ARE SOME POSSIBILITIES FOR SOME LAKE ENHANCEMENT FOR AREAS
NEAR THE LAKE LATE TONIGHT AND INTO SATURDAY AS THE FLOW TURNS EAST
NORTHEASTWARD. HOWEVER...THERMODYNAMICS OVER THE LAKE DO NOT APPEAR
TO BE VERY FAVORABLE FOR ANY SIGNIFICANT LAKE ENHANCEMENT POTENTIAL.
DELTA T`S LOOK TO REMAIN AROUND 12 DEGREES CELSIUS AND EQUILIBRIUM
LEVELS NEVER APPEAR TO REACH INTO THE DENDRITIC GROWTH ZONE.
SO...OVERALL...IT STILL APPEARS SNOWFALL AMOUNTS WILL RANGE FROM
ABOUT 5 TO 8 INCHES ACROSS THE WARNING AREA...3 TO 6 INCHES IN THE
ADVISORY AREAS...AND 2 TO 3 INCHES AROUND NORTHEASTERN
ILLINOIS...AND AN INCH OR LESS ACROSS NORTH CENTRAL ILLINOIS.
ONCE THE SNOW ENDS...THE NORTHWESTERLY FLOW WILL ALLOW COLDER AIR
TO SPILL BACK ACROSS THE REGION SETTING UP ANOTHER COLD SUNDAY
MORNING.
KJB
MEDIUM-LONG RANGE...SUNDAY THROUGH NEXT FRIDAY...
HIGHLIGHTS OF THE MEDIUM-LONG RANGE FORECAST PERIOD ARE CONTINUED
NORTHWEST UPPER FLOW WITH A PARADE OF WEAK CLIPPER SYSTEMS INTO
MID-WEEK...THEN A SHIFT TOWARD SOUTHWEST FLOW ALOFT MID/LATE NEXT
WEEK AS UPPER RIDGE BUILDS ACROSS THE EASTERN PACIFIC AND GULF OF
ALASKA AND INDUCES DOWNSTREAM LONG WAVE TROUGH ACROSS WESTERN NORTH
AMERICA. THIS WILL SUPPORT A TRANSITION FROM BELOW NORMAL TEMPS
SUN-WED...WITH THE POTENTIAL FOR A BRIEF WARM-UP THURS-EARLY FRI
AHEAD OF WESTERN TROUGH.
SUNDAY THROUGH WEDNESDAY...
MID-LEVEL SHORT WAVE TROUGH AXIS ASSOCIATED WITH EARLY WEEKEND
WINTER STORM WILL BE WELL EAST OF THE REGION BY SUNDAY MORNING.
MID/UPPER LEVEL LOW OVER DEVELOPS OVER ONTARIO AND THE NORTHERN
LAKES HOWEVER...WITH REGION OF ENHANCED NORTHWEST FLOW ALOFT FROM
THE NORTHERN PLAINS TO THE MIDWEST. SEVERAL MINOR AMPLITUDE RIPPLES
ARE INDICATED IN MODEL GUIDANCE WHICH PROPAGATE ALONG LOW LEVEL
BAROCLINIC ZONE WHICH STRETCHES NORTHWEST-SOUTHEAST ACROSS THE
REGION. SOME TIMING DIFFERENCES WITH THE MORE SUBTLE DISTURBANCES
BETWEEN MODELS...THOUGH IT APPEARS A WEAK WAVE WILL TRAVERSE THE
AREA SUNDAY WITH A SOMEWHAT BETTER DEFINED VORT MOVING OVER THE AREA
SUNDAY NIGHT AND EARLY MONDAY. FORECAST SOUNDINGS AND TIME/HEIGHT
DEPICTIONS INDICATE GENERALLY DRY MOISTURE PROFILES...WITH ONLY A
POCKET OF DEEPER MID-LEVEL MOISTURE SUNDAY NIGHT-EARLY MONDAY WITH
ISENTROPIC FORCING AHEAD OF THE STRONGER WAVE. THUS THE BEST
POTENTIAL FOR A LITTLE LIGHT SNOW APPEARS BE SUNDAY NIGHT...THOUGH
WITH LITTLE ACCUMULATION EXPECTED (A DUSTING TO PERHAPS A HALF INCH)
AS LIFT APPEARS GENERALLY WEAK AND WELL BELOW THE DENDRITIC GROWTH
ZONE. WEAK ASCENT LINGERS INTO MONDAY...ESPECIALLY ACROSS THE
NORTHEAST/EAST PARTS OF THE CWA WITH THE LEFT EXIT REGION OF THE
UPPER JET STREAK HELPING TO MAINTAIN SOME LARGE SCALE SUPPORT DURING
THE DAY. A MORE AMPLIFIED SHORT WAVE IS PROGGED TO DIG ACROSS THE
WESTERN GREAT LAKES REGION ON TUESDAY...THOUGH THE BEST WARM
ADVECTION AND ISENTROPIC UPGLIDE APPEARS TO REMAIN JUST TO THE
NORTH/NORTHEAST OF THE CWA...THOUGH A REINFORCING PUSH OF COLDER AIR
DOES ARRIVE TUESDAY NIGHT WITH A COLD FRONT.
COLDEST CONDITIONS LOOK TO OCCUR SUNDAY BEHIND THE EARLY WEEKEND
WINTER STORM...WITH HIGHS IN THE TEENS AND LOWS IN THE SINGLE DIGITS
TO AROUND 10 ABOVE. SOME MODERATION OCCURS MON-TUE WITH THE WEAK BUT
NEARLY PERSISTENT WARM ADVECTION ASSOCIATED WITH THE AFOREMENTIONED
CLIPPERS. A LITTLE COOLER TUESDAY NIGHT-WEDNESDAY BEHIND TUESDAY
NIGHTS COLD FRONT.
AS INDICATED ABOVE...DEVELOPING UPPER RIDGING OVER THE EAST PACIFIC
AND TROUGH INDUCEMENT OVER THE WESTERN CONUS WEDNESDAY-THURSDAY
RESULTS IN SURFACE LOW PRESSURE DEVELOPMENT OVER THE PLAINS BY EARLY
THURSDAY. FAIRLY DECENT MODEL AGREEMENT IN THIS LOW DEEPENING AND
LIFTING NORTHEAST ACROSS MINNESOTA AND THE NORTHERN GREAT LAKES
THURSDAY AND THURSDAY NIGHT...PLACING WFO LOT CWA IN THE WARM SECTOR
AS WARM FRONT LIFTS NORTH. SHALLOW COLD SURFACE LAYER MAY RESULT IN
A LITTLE MIXED PRECIPITATION THURSDAY MORNING ESPECIALLY NORTH AS
WARMING OCCURS MORE VIGOROUSLY ALOFT...THOUGH GFS/ECMWF RUNS
INDICATE THAT LOW LEVELS WARM ENOUGH TO PRODUCE MAINLY RAIN BY
THURSDAY EVENING/NIGHT. SOME TIMING DIFFERENCES DO ARISE WITH THE
NEW 12Z ECMWF (THE 00Z RUN WAS IN BETTER AGREEMENT WITH THE 00/12Z
GFS AND ENSEMBLE MEMBERS)...WITH THE ECMWF FASTER WITH THE LOW
LIFTING ACROSS THE NORTHERN LAKES EARLY FRIDAY AND BRINGING THE
TRAILING COLD FRONT THROUGH FASTER. CONTINUE TO FAVOR A SLIGHTLY
SLOWER SOLUTION SIMILAR TO THE 00Z EC/12Z GFS AND GEFS RUNS. THIS
WOULD SUPPORT TEMPS POTENTIALLY WARMING INTO THE 35-40 F RANGE
THURSDAY AND POTENTIALLY INTO THE 40S/EVEN 50 ACROSS THE SOUTHEAST
FRIDAY PRIOR TO COLD FRONTAL PASSAGE. PRECIP POTENTIAL APPEARS TO BE
GREATEST ALONG/AHEAD OF THE COLD FRONT INTO FRIDAY. DECREASING
THICKNESSES IN COLDER AIR BEHIND THE FRONT PORTEND A CHANGE BACK TO
SNOW FROM THE WEST FRIDAY.
THINGS LOOK POTENTIALLY INTERESTING JUST BEYOND THE END OF DAY
7...AS SOUTHWEST-NORTHEAST ORIENTED BAROCLINIC ZONE COULD BECOME THE
FOCUS FOR A COUPLE OF ROUNDS OF WINTRY PRECIP SOMEWHERE FROM HERE
INTO THE OHIO VALLEY...WHILE HIGH PRESSURE AND A RETURN TO
SUB-AVERAGE TEMPS BUILD BACK ACROSS THE UPPER MIDWEST.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* SNOW BEGINNING BETWEEN BY 0430Z AND PERSISTING INTO SATURDAY
WITH TEMPORARY HEAVIER RATES OCCURRING BETWEEN 06Z-13Z.
* QUICKLY LOWERING CIGS THROUGH THE IFR CATEGORY AFTER ONSET AND
GRADUALLY LOWERING VISIBILITY.
* EASTERLY WINDS AROUND 10 KT THROUGH THE NIGHT AND SATURDAY
MORNING.
* CHANCE FOR LAKE ENHANCEMENT OF SNOW DURING THE DAY INTO EARLY
EVE SATURDAY.
//DISCUSSION...UPDATED 03Z...
OBSERVATIONAL AND RADAR TRENDS GENERALLY SUPPORT PREVIOUS THINKING
FROM 00Z. SNOW WILL SPREAD INTO THE CHICAGO AREA TAF SITES
THROUGH 0430Z WITH CIGS COMING DOWN FAIRLY QUICKLY AFTER ONSET AND
VISIBILITY DROPPING MORE RAPIDLY INTO THE OVERNIGHT. HAVE SEEN SOME
1SM OBSERVATIONS AS FAR NORTH AS JOLIET. WE DO EXPECT MODEST
SNOWFALL RATES TO BE TEMPORARY AT MOST TAF SITES...AS RADAR TRENDS
HAVE NOT REFLECTED SINGLE WELL-DEFINED BANDS AND MORE EMBEDDED
CONVECTIVE-LIKE SNOW ACTIVITY.
PREV DISCUSSION...UPDATED 00Z...
LOW PRESSURE ACROSS THE SOUTHERN PLAINS WILL SHIFT EAST TONIGHT
WITH ITS EFFECT STRETCHING WELL TO THE NORTH OVER OUR REGION. SNOW
WILL SPREAD NORTH THIS EVENING...THOUGH ITS RATE OF FORWARD
PROGRESSION WILL LIKELY SLOW. THE HEAVIEST SNOWFALL RATES WILL
MAINLY REMAIN SOUTH OF THE TAF SITES TONIGHT...HOWEVER GYY AND
MAYBE EVEN MDW MAY TOUCH SOME OF THESE RATES THAT WILL BRING
VISIBILITY DOWN TO NEAR A HALF MILE. THE PRIMARY TIME FOR THESE
WOULD BE OVERNIGHT. WARM AIR ADVECTION ALOFT SETUPS SUCH AS THESE
TYPICALLY SEE CIGS COME DOWN QUICKLY AND THIS SCENARIO SHOULD SEE
THAT UNFOLD AS WELL. THROUGH TONIGHT EASTERLY WINDS WILL CONTINUE
AROUND 10 KT.
FOR SATURDAY...THE ENDING OF THIS SNOW EVENT WILL NOT BE A CLEAN
QUICK ABRUPT END. FOR ONE...THE OVERALL SYSTEM WILL SLOW...AND
SECOND THE LAKE MAY COME INTO PLAY TO ENHANCE SNOWFALL SOME INTO
THE AFTERNOON AND EVEN EARLY EVE. IN GENERAL IF IFR VISIBILITY IN
SNOW EXISTS IN THE LATE MORNING AND AFTERNOON IT SHOULD BECOME
MORE TEMPORARY. CIGS WILL BE VERY SLOW TO IMPROVE THOUGH GIVEN THE
SYNOPTIC SETUP. WINDS SHOULD SHIFT TO NORTHEAST IN THE AFTERNOON
AND THEN TO NORTHWEST AROUND THE EARLY EVE PERIOD.
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM CONFIDENCE ON SNOW ARRIVAL TIME. HIGH ON HEAVIEST SNOWFALL
RATES TEMPORARILY OCCURRING BETWEEN 06Z AND 13Z.
* HIGH THAT CIGS WILL LOWER QUICKLY. MEDIUM ON TIMING OF LOWEST
CIGS AND HOW LOW THEY WILL GO.
* MEDIUM-HIGH ON HOW LOW VISIBILITY WILL GET. MEDIUM ON EXACT
TIMING.
* HIGH ON WINDS THROUGH SATURDAY AFTERNOON AND THAT SPEEDS WILL
BE AROUND 10 KT MUCH OF THAT TIME.
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...MVFR WITH A CHC OF SNOW.
MONDAY...SLIGHT CHC OF SNOW.
TUESDAY-WEDNESDAY...VFR LIKELY.
THURSDAY...CHC OF RAIN OR SNOW.
MTF
&&
.MARINE...
144 PM CST
A LARGE AREA OF HIGH PRESSURE IS SETTLING OVER THE SERN CONUS AS WEAK
LOW PRESSURE MOVING ACROSS NRN NEW ENGLAND DAGS A COLD FRONT DOWN
LAKE MICHIGAN. THE FRONT HAS STALLED OUT OVER THE SOUTHERN TIP OF
THE LAKE LEADING TO LIGHT AND VARIABLE WINDS OVER THE SOUTHERN TIP
OF THE LAKE. NORTH WINDS ARE STRENGTHENING OVER THE NORTHERN
PORTIONS OF THE LAKE AS ANOTHER AREA OF ARCTIC HIGH PRESSURE BUILDS
OUT OF CANADA AND SPREADS ACROSS THE NRN PLAINS AND UPPER GREAT
LAKES. THE FRONT OVER THE SRN PORTIONS OF THE LAKE WILL WASH OUT AS
A DOUBLE BARRELED LOW PRESSURE SYSTEM DEVELOPS OVER THE SRN AND
CNTRL PLAINS. THE COMPLEX LOW PRESSURE SYSTEM WILL TRACK EWD THIS
EVENING WITH ONE CIRCULATION CENTER TRACKING THROUGH CNTRL IL AND
ANOTHER TRACKING THROUGH THE LOWER MISSISSIPPI VALLEY. A WEAK
INVERTED SFC TROUGH AXIS ASSOCIATED WITH THE MORE NORTHERN OF THE
TWO LOWS WILL MOVE ACROSS THE LAKE EARLY TOMORROW. AS THE HIGH
BUILDS ACROSS THE UPPER GREAT LAKES THIS EVENING...WINDS OVER THE
ENTIRE LAKE WILL GRADUALLY TURN EASTERLY...BUT AS THE INVERTED
TROUGH AXIS CROSSES THE LAKE TOMORROW...WINDS OVER THE LAKE WILL
GRADUALLY BACK THROUGH NELY TO NORTHERLY TOMORROW EVENING AND THEN
THEN CONTINUE TO BACK TO NWLY BY LATE SATURDAY NIGHT AND EARLY
SUNDAY MORNING. AS COLDER AIR ASSOCIATED WITH THE ARCTIC HIGH IS
DRAWN OVER THE LAKE...THE STRONG COLD ADVECTION AND STRENGTHENING
PRESSURE GRADIENT WILL LEAD TO WINDS INCREASING TO AROUND 30KT
THROUGH THE DAY ON SUNDAY. WHILE GALES ARE NOT EXPECTED AT THIS
TIME...THE STRONG WINDS AND COLDER AIR WILL LEAD TO A CHANCE FOR
LIGHT TO MODERATE FREEZING SPRAY ON SUNDAY. THE BRISK NWLY WINDS
WILL PERSIST THROUGH SUNDAY NIGHT...AND THEN ANOTHER HIGH WILL BUILD
ACROSS LAKE MICHIGAN ON MONDAY...ALLOWING WINDS TO TEMPORARILY
SUBSIDE. AS THE HIGH MOVES OFF TO THE EAST ON TUESDAY...ANOTHER LOW
WILL TRACK ACROSS SCNTRL CANADA...LEADING TO INCREASING SWLY-WLY
WINDS BY TUESDAY...WHICH SHOULD PERSIST THROUGH THE MIDDLE OF NEXT
WEEK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ033-ILZ039 UNTIL NOON SATURDAY.
WINTER WEATHER ADVISORY...ILZ019-ILZ021-ILZ022-ILZ023-ILZ032
UNTIL NOON SATURDAY.
WINTER WEATHER ADVISORY...ILZ014 UNTIL 6 PM SATURDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002 UNTIL NOON SATURDAY.
WINTER STORM WARNING...INZ010-INZ011-INZ019 UNTIL NOON SATURDAY.
LM...SMALL CRAFT ADVISORY...LMZ740...MIDNIGHT SATURDAY TO 3 PM
SATURDAY.
SMALL CRAFT ADVISORY...LMZ741-LMZ742-LMZ743...3 AM SATURDAY TO 3
PM SATURDAY.
&&
$$
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[top]
Area Forecast Discussion
National Weather Service Lincoln IL
848 PM CST Fri Dec 13 2013
.DISCUSSION...
ISSUED 837 PM CST Fri Dec 13 2013
Have made some minor tweaks to grids and reworded some of the
precip type wording for this evening. Otherwise, no major changes
anticipated.
Lull between initial wave along front to our northwest and the
main area of diffluence associated with approaching southern
stream system is moving into the region southeast of I-55. As
precip over Arkansas moves northeast, snow will likely increase in
coverage and intensity again after midnight. Current snow amount
forecasts may be a bit overdone in this area, but hesitate to make
major changes with the second wave yet to come.
Somewhat concerned about the area northwest of the Illinois River.
2-3 inches have been reported across Fulton County to this point
and that area remains in the deformation area and near the surface
warm front. Would not be surprised if several reports approach 6
inches in that area.
Barker
&&
.AVIATION...
ISSUED 515 PM CST Fri Dec 13 2013
With wet bulb zero below freezing, temperatures have dived as pcpn
began. All terminals have either started as snow or quickly
transitioned to snow. High res models suggest that vsbys will be
quite variable this evening with potential banding and lulls. Will
have to be quite general with timing. They do suggest a let up
along and east of I-55 after 04z before next wave comes in after
06z. Surface low should push east of Illinois by late morning
Saturday ending chances of measureable snow. A few flurries may
linger until main short wave axis moves through Illinois around 00z.
Warm front is set up just north of TAF sites and should move
little until surface low pushes through. This should keep winds
100-170 degrees until after 12z. once the low pushes east of the
terminals, winds will shift to 310-360 and pick up slightly.
However, gradient is rather weak for a winter storm and wind
speeds of 5-10 kts extent are expected prior to the surface low
with 5-15 kts after the shift.
Barker
&&
.PREV DISCUSSION...
ISSUED 205 PM CST Fri Dec 13 2013
Clouds continue to lower and thicken this afternoon ahead of the winter
storm system expected to affect our area tonight into Saturday. Already
seeing some light rain and sleet pushing into extreme southwest IL early
this afternoon as the upper level wave tracks across the southern Plains.
SHORT TERM...Tonight through Monday
Significant snowfall expected over parts of central through east
central Illinois tonight thru Saturday morning...but not much in
the way of strong winds with this particular storm system.
The main forecast challenge this period will be with snowfall totals
starting tonight thru early Saturday afternoon. Will continue to hold
on to the winter weather advisory with a few locations across central
thru east central Illinois edging close to 6 inches by the time the
snow tapers off to flurries Saturday afternoon. Forecast soundings,
at least for a few hours late this afternoon into early this evening,
continues to suggest a brief period of rain, sleet and possibly some
freezing rain over parts of west central Illinois before we see the
lower layers saturate and cool sufficiently enough to support mostly
snow thru the overnight hours. NAM-WRF time height cross sections
indicate the best forcing coupled with the deeper moisture/and dendritic
growth zone will be mainly tonight thru about 14z Saturday. Using a
13:1 SLR indicates 4 to 6 inches will be common across the area by the
time the snow diminishes on Saturday.
Still a bit concerned about the potential for banding, especially
along the inverted trof, which is expected to push across our area
early Saturday morning. Several of the hi-res models suggest the
threat is there but unfortunately, are not very consistent in depicting
the location. Past few runs of the HRRR have indicated one band to move
north across the area this evening, with a break over parts of central
thru east central IL around midnight, before another band pushes
acrs the area towards morning with the inverted trof. Wouldn`t at all
be surprised to see a few areas with 6 to 8 inches accumulation by late
Saturday morning, but at this time, the threat appears too isolated.
Models are a bit more consistent in showing an increase in snow totals
just to our east as the weak surface low and inverted trof shift off
to our east and we see a better coupled 250mb jet structure and
associated upper level divergence.
The upper level wave and surface reflection should push well off
to our east by late tomorrow afternoon with all of the precip shifting
out of the forecast area. The weather should be on the quiet side for
the rest of the short term period with a brief cool down in the wake
of the winter system Saturday night through Sunday night before we see
milder temperatures move into our area early next week.
LONG TERM...Tuesday through Friday
Medium range models indicate some fast moving waves approaching
our area from the northwest at the start of this forecast period
with little in the way of moisture available to produce much in
the way of precip in our area. The first such wave will move across
the lower Great Lakes on Monday with a hint for some very light
precip during the day, mainly to our north. The next wave moves
quickly southeast along the tight 850 mb baroclinic zone on Tue,
at least according to the latest ECMWF, with again little in the
way of moisture to work with. Will continue to keep the first part
of the week dry but could see some low chance pops added in later
forecasts.
Warmer temperatures expected in the Wed-Fri time frame as a deep
upper level trof drops southeast into the southern Rockies and
brings about a strong southwest flow aloft over our area. This
should result in mild temps, at least compared to what we have
been experiencing, through the end of the week. However, as the
deep upper level trof edges east into the central Plains, a strong
Arctic cold front will approach our area on Friday increasing the
precip chances Thursday night into Friday, followed by much colder
weather for next weekend.
Smith
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until Noon CST Saturday FOR ILZ038-
042>046-051>057-061>063-066>068-071>073.
WINTER WEATHER ADVISORY until 6 AM CST Saturday FOR ILZ027>031-
036-037-040-041-047>050.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
609 PM CST FRI DEC 13 2013
.DISCUSSION...
319 PM CST
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...
NOT MUCH HAS CHANGED WITH THE CURRENT THINKING FOR TONIGHT AND
SATURDAY REGARDING SNOWFALL AMOUNTS AND PLACEMENT. THE CURRENT
WATER VAPOR IMAGERY CONTINUES TO INDICATE A DECENT DISTURBANCE
NEAR THE TEXAS PANHANDLE EARLY THIS AFTERNOON...WITH SEVERAL LEAD
DISTURBANCES ACROSS OK AND INTO WESTERN MO. PROFILER AND VWP DATA
ACROSS THE SOUTHERN PLAINS AND MID MISSISSIPPI VALLEY INDICATES
THAT AROUND 30KT OF SOUTHWESTERLY FLOW AROUND 850 MB HAS DEVELOPED
IN ASSOCIATION WITH THIS SYSTEM. THIS IS ALLOWING FOR SOME DECENT
MOISTURE TRANSPORT AND ISENTROPIC ASCENT ACROSS THE MISSOURI AND
WEST CENTRAL ILLINOIS THIS AFTERNOON. THIS HAS PRODUCED A GOOD
AREA OF PRECIPITATION ACROSS MISSOURI...ESPECIALLY ALONG THE
LEADING EDGE OF THE BETTER MOISTURE TRANSPORT.
I EXPECT THIS AREA OF PRECIP TO CONTINUE TO MOVE NORTHWARD AND TO
OVERSPREAD MOST AREAS ALONG AND SOUTH OF INTERSTATE 80 THROUGH THE
EVENING AS THE BETTER MOISTURE GETS DRAWN NORTHWARD IN ASSOCIATION
WITH THE APPROACHING SOUTHERN STREAM SYSTEM. IT APPEARS LIKELY THAT
A BAND OF MODERATE TO HEAVY SNOW WILL SET UP THIS EVENING ACROSS MY
SOUTHERN COUNTIES...IN ASSOCIATION WITH A DEVELOPING BAND OF
FRONTOGENESIS. THE ENHANCED FORCING FOR ASCENT WITHIN THE
FRONTOGENETIC CIRCULATION WILL ALLOW FOR SOME DECENT ASCENT WITHIN
THE DENDRITIC GROWTH ZONE. THIS ALONG WITH THE FACT THAT STEEP LAPSE
RATES AND -EPV EXITS WITHIN AND ABOVE THIS ZONE ALSO SUGGESTS THAT
THEIR WILL BE SOME FAIRLY EFFICIENT SNOWFALL PRODUCTION WITHIN THIS
BAND OF SNOW. WITH THIS IN MIND...IT APPEARS THAT SNOWFALL RATES
COULD APPROACH 1 INCH PER HOUR FOR A COUPLE HOUR PERIOD THIS
EVENING...ESPECIALLY TO THE SOUTH OF INTERSTATE 80 WITHIN AND NEAR
THE CURRENT WINTER STORM WARNING.
A SECOND AREA OF SNOW WILL BE FAVORED...MAINLY ACROSS SOUTHERN
WISCONSIN THIS EVENING AS A SECONDARY AXIS OF FRONTOGENESIS DEVELOPS
ALONG A BAROCLINIC RIBBON...AND COMBINES WITH INCREASING FLOW AND LOW
LEVEL CONVERGENCE OFF OF LAKE MICHIGAN. HOWEVER...MOST HIGH RES
GUIDANCE CONTINUES TO FAVOR AREAS NORTH OF THE ILLINOIS BOARDER.
THEREFORE...IT APPEARS MOST OF NORTHERN ILLINOIS WILL REMAIN SNOW
FREE...THROUGH AT LEAST MID TO LATE EVENING.
THE SNOW SHOULD BEGIN TO SPREAD NORTHWARD BY LATE THIS EVENING...AND
BEGIN IMPACTING MOST OF NORTHERN ILLINOIS BY OR SHORTLY AFTER
MIDNIGHT AS THE SURFACE INVERTED TROUGH BECOMES ORIENTED NORTH TO
SOUTH ACROSS THE AREA OVERNIGHT. THE SNOW WILL CONTINUE INTO
SATURDAY AS SOME LARGER SCALE SUPPORT FOR ASCENT OVERSPREADS THE
AREA IN ASSOCIATION WITH THE APPROACHING NORTHERN STREAM SHORT WAVE.
THIS COULD EVEN LEAD TO A BIT IN AN UPTICK TO THE SNOWFALL
INTENSITY...PARTICULARLY ACROSS EASTERN ILLINOIS AND NORTHWESTERN
INDIANA...WHERE MID LEVEL DEFORMATION WILL CONTINUE IN ASSOCIATION
WITH THE MID LEVEL CIRCULATION. THE SNOW WILL GRADUALLY END ACROSS
NORTHERN ILLINOIS AS THE FLOW TURNS NORTHWESTERLY. SOME LINGERING
LAKE EFFECT SNOW SHOWERS ARE POSSIBLE ACROSS NORTHWESTERN INDIANA
INTO SATURDAY EVENING.
THERE ARE SOME POSSIBILITIES FOR SOME LAKE ENHANCEMENT FOR AREAS
NEAR THE LAKE LATE TONIGHT AND INTO SATURDAY AS THE FLOW TURNS EAST
NORTHEASTWARD. HOWEVER...THERMODYNAMICS OVER THE LAKE DO NOT APPEAR
TO BE VERY FAVORABLE FOR ANY SIGNIFICANT LAKE ENHANCEMENT POTENTIAL.
DELTA T`S LOOK TO REMAIN AROUND 12 DEGREES CELSIUS AND EQUILIBRIUM
LEVELS NEVER APPEAR TO REACH INTO THE DENDRITIC GROWTH ZONE.
SO...OVERALL...IT STILL APPEARS SNOWFALL AMOUNTS WILL RANGE FROM
ABOUT 5 TO 8 INCHES ACROSS THE WARNING AREA...3 TO 6 INCHES IN THE
ADVISORY AREAS...AND 2 TO 3 INCHES AROUND NORTHEASTERN
ILLINOIS...AND AN INCH OR LESS ACROSS NORTH CENTRAL ILLINOIS.
ONCE THE SNOW ENDS...THE NORTHWESTERLY FLOW WILL ALLOW COLDER AIR
TO SPILL BACK ACROSS THE REGION SETTING UP ANOTHER COLD SUNDAY
MORNING.
KJB
MEDIUM-LONG RANGE...SUNDAY THROUGH NEXT FRIDAY...
HIGHLIGHTS OF THE MEDIUM-LONG RANGE FORECAST PERIOD ARE CONTINUED
NORTHWEST UPPER FLOW WITH A PARADE OF WEAK CLIPPER SYSTEMS INTO
MID-WEEK...THEN A SHIFT TOWARD SOUTHWEST FLOW ALOFT MID/LATE NEXT
WEEK AS UPPER RIDGE BUILDS ACROSS THE EASTERN PACIFIC AND GULF OF
ALASKA AND INDUCES DOWNSTREAM LONG WAVE TROUGH ACROSS WESTERN NORTH
AMERICA. THIS WILL SUPPORT A TRANSITION FROM BELOW NORMAL TEMPS
SUN-WED...WITH THE POTENTIAL FOR A BRIEF WARM-UP THURS-EARLY FRI
AHEAD OF WESTERN TROUGH.
SUNDAY THROUGH WEDNESDAY...
MID-LEVEL SHORT WAVE TROUGH AXIS ASSOCIATED WITH EARLY WEEKEND
WINTER STORM WILL BE WELL EAST OF THE REGION BY SUNDAY MORNING.
MID/UPPER LEVEL LOW OVER DEVELOPS OVER ONTARIO AND THE NORTHERN
LAKES HOWEVER...WITH REGION OF ENHANCED NORTHWEST FLOW ALOFT FROM
THE NORTHERN PLAINS TO THE MIDWEST. SEVERAL MINOR AMPLITUDE RIPPLES
ARE INDICATED IN MODEL GUIDANCE WHICH PROPAGATE ALONG LOW LEVEL
BAROCLINIC ZONE WHICH STRETCHES NORTHWEST-SOUTHEAST ACROSS THE
REGION. SOME TIMING DIFFERENCES WITH THE MORE SUBTLE DISTURBANCES
BETWEEN MODELS...THOUGH IT APPEARS A WEAK WAVE WILL TRAVERSE THE
AREA SUNDAY WITH A SOMEWHAT BETTER DEFINED VORT MOVING OVER THE AREA
SUNDAY NIGHT AND EARLY MONDAY. FORECAST SOUNDINGS AND TIME/HEIGHT
DEPICTIONS INDICATE GENERALLY DRY MOISTURE PROFILES...WITH ONLY A
POCKET OF DEEPER MID-LEVEL MOISTURE SUNDAY NIGHT-EARLY MONDAY WITH
ISENTROPIC FORCING AHEAD OF THE STRONGER WAVE. THUS THE BEST
POTENTIAL FOR A LITTLE LIGHT SNOW APPEARS BE SUNDAY NIGHT...THOUGH
WITH LITTLE ACCUMULATION EXPECTED (A DUSTING TO PERHAPS A HALF INCH)
AS LIFT APPEARS GENERALLY WEAK AND WELL BELOW THE DENDRITIC GROWTH
ZONE. WEAK ASCENT LINGERS INTO MONDAY...ESPECIALLY ACROSS THE
NORTHEAST/EAST PARTS OF THE CWA WITH THE LEFT EXIT REGION OF THE
UPPER JET STREAK HELPING TO MAINTAIN SOME LARGE SCALE SUPPORT DURING
THE DAY. A MORE AMPLIFIED SHORT WAVE IS PROGGED TO DIG ACROSS THE
WESTERN GREAT LAKES REGION ON TUESDAY...THOUGH THE BEST WARM
ADVECTION AND ISENTROPIC UPGLIDE APPEARS TO REMAIN JUST TO THE
NORTH/NORTHEAST OF THE CWA...THOUGH A REINFORCING PUSH OF COLDER AIR
DOES ARRIVE TUESDAY NIGHT WITH A COLD FRONT.
COLDEST CONDITIONS LOOK TO OCCUR SUNDAY BEHIND THE EARLY WEEKEND
WINTER STORM...WITH HIGHS IN THE TEENS AND LOWS IN THE SINGLE DIGITS
TO AROUND 10 ABOVE. SOME MODERATION OCCURS MON-TUE WITH THE WEAK BUT
NEARLY PERSISTENT WARM ADVECTION ASSOCIATED WITH THE AFOREMENTIONED
CLIPPERS. A LITTLE COOLER TUESDAY NIGHT-WEDNESDAY BEHIND TUESDAY
NIGHTS COLD FRONT.
AS INDICATED ABOVE...DEVELOPING UPPER RIDGING OVER THE EAST PACIFIC
AND TROUGH INDUCEMENT OVER THE WESTERN CONUS WEDNESDAY-THURSDAY
RESULTS IN SURFACE LOW PRESSURE DEVELOPMENT OVER THE PLAINS BY EARLY
THURSDAY. FAIRLY DECENT MODEL AGREEMENT IN THIS LOW DEEPENING AND
LIFTING NORTHEAST ACROSS MINNESOTA AND THE NORTHERN GREAT LAKES
THURSDAY AND THURSDAY NIGHT...PLACING WFO LOT CWA IN THE WARM SECTOR
AS WARM FRONT LIFTS NORTH. SHALLOW COLD SURFACE LAYER MAY RESULT IN
A LITTLE MIXED PRECIPITATION THURSDAY MORNING ESPECIALLY NORTH AS
WARMING OCCURS MORE VIGOROUSLY ALOFT...THOUGH GFS/ECMWF RUNS
INDICATE THAT LOW LEVELS WARM ENOUGH TO PRODUCE MAINLY RAIN BY
THURSDAY EVENING/NIGHT. SOME TIMING DIFFERENCES DO ARISE WITH THE
NEW 12Z ECMWF (THE 00Z RUN WAS IN BETTER AGREEMENT WITH THE 00/12Z
GFS AND ENSEMBLE MEMBERS)...WITH THE ECMWF FASTER WITH THE LOW
LIFTING ACROSS THE NORTHERN LAKES EARLY FRIDAY AND BRINGING THE
TRAILING COLD FRONT THROUGH FASTER. CONTINUE TO FAVOR A SLIGHTLY
SLOWER SOLUTION SIMILAR TO THE 00Z EC/12Z GFS AND GEFS RUNS. THIS
WOULD SUPPORT TEMPS POTENTIALLY WARMING INTO THE 35-40 F RANGE
THURSDAY AND POTENTIALLY INTO THE 40S/EVEN 50 ACROSS THE SOUTHEAST
FRIDAY PRIOR TO COLD FRONTAL PASSAGE. PRECIP POTENTIAL APPEARS TO BE
GREATEST ALONG/AHEAD OF THE COLD FRONT INTO FRIDAY. DECREASING
THICKNESSES IN COLDER AIR BEHIND THE FRONT PORTEND A CHANGE BACK TO
SNOW FROM THE WEST FRIDAY.
THINGS LOOK POTENTIALLY INTERESTING JUST BEYOND THE END OF DAY
7...AS SOUTHWEST-NORTHEAST ORIENTED BAROCLINIC ZONE COULD BECOME THE
FOCUS FOR A COUPLE OF ROUNDS OF WINTRY PRECIP SOMEWHERE FROM HERE
INTO THE OHIO VALLEY...WHILE HIGH PRESSURE AND A RETURN TO
SUB-AVERAGE TEMPS BUILD BACK ACROSS THE UPPER MIDWEST.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* POTENTIAL FOR MVFR CIGS PRIOR TO SNOW ARRIVAL.
* SNOW BEGINNING BETWEEN 02Z-04Z AND PERSISTING INTO SATURDAY WITH
TEMPORARY HEAVIER RATES OCCURRING BETWEEN 05Z-13Z.
* QUICKLY LOWERING CIGS THROUGH THE IFR CATEGORY AFTER ONSET AND
GRADUALLY LOWERING VISIBILITY.
* EASTERLY WINDS AROUND 10 KT THROUGH THE NIGHT AND SATURDAY
MORNING.
* CHANCE FOR LAKE ENHANCEMENT OF SNOW DURING THE DAY INTO EARLY
EVE SATURDAY.
//DISCUSSION...UPDATED 00Z...
LOW PRESSURE ACROSS THE SOUTHERN PLAINS WILL SHIFT EAST TONIGHT
WITH ITS EFFECT STRETCHING WELL TO THE NORTH OVER OUR REGION. SNOW
WILL SPREAD NORTH THIS EVENING...THOUGH ITS RATE OF FORWARD
PROGRESSION WILL LIKELY SLOW. THE HEAVIEST SNOWFALL RATES WILL
MAINLY REMAIN SOUTH OF THE TAF SITES TONIGHT...HOWEVER GYY AND
MAYBE EVEN MDW MAY TOUCH SOME OF THESE RATES THAT WILL BRING
VISIBILITY DOWN TO NEAR A HALF MILE. THE PRIMARY TIME FOR THESE
WOULD BE OVERNIGHT. WARM AIR ADVECTION ALOFT SETUPS SUCH AS THESE
TYPICALLY SEE CIGS COME DOWN QUICKLY AND THIS SCENARIO SHOULD SEE
THAT UNFOLD AS WELL. THROUGH TONIGHT EASTERLY WINDS WILL CONTINUE
AROUND 10 KT.
FOR SATURDAY...THE ENDING OF THIS SNOW EVENT WILL NOT BE A CLEAN
QUICK ABRUPT END. FOR ONE...THE OVERALL SYSTEM WILL SLOW...AND
SECOND THE LAKE MAY COME INTO PLAY TO ENHANCE SNOWFALL SOME INTO
THE AFTERNOON AND EVEN EARLY EVE. IN GENERAL IF IFR VISIBILITY IN
SNOW EXISTS IN THE LATE MORNING AND AFTERNOON IT SHOULD BECOME
MORE TEMPORARY. CIGS WILL BE VERY SLOW TO IMPROVE THOUGH GIVEN THE
SYNOPTIC SETUP. WINDS SHOULD SHIFT TO NORTHEAST IN THE AFTERNOON
AND THEN TO NORTHWEST AROUND THE EARLY EVE PERIOD.
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM CONFIDENCE ON SNOW ARRIVAL TIME. HIGH ON HEAVIEST SNOWFALL
RATES TEMPORARILY OCCURRING BETWEEN 05Z AND 13Z.
* HIGH THAT CIGS WILL LOWER QUICKLY. MEDIUM ON TIMING OF LOWEST
CIGS AND HOW LOW THEY WILL GO.
* MEDIUM-HIGH ON HOW LOW VISIBILITY WILL GET. MEDIUM ON EXACT
TIMING.
* HIGH ON WINDS THROUGH SATURDAY AFTERNOON AND THAT SPEEDS WILL
BE AROUND 10 KT MUCH OF THAT TIME.
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...MVFR WITH A CHC OF SNOW.
MONDAY...SLIGHT CHC OF SNOW.
TUESDAY-WEDNESDAY...VFR LIKELY.
THURSDAY...CHC OF RAIN OR SNOW.
MTF
&&
.MARINE...
144 PM CST
A LARGE AREA OF HIGH PRESSURE IS SETTLING OVER THE SERN CONUS AS WEAK
LOW PRESSURE MOVING ACROSS NRN NEW ENGLAND DAGS A COLD FRONT DOWN
LAKE MICHIGAN. THE FRONT HAS STALLED OUT OVER THE SOUTHERN TIP OF
THE LAKE LEADING TO LIGHT AND VARIABLE WINDS OVER THE SOUTHERN TIP
OF THE LAKE. NORTH WINDS ARE STRENGTHENING OVER THE NORTHERN
PORTIONS OF THE LAKE AS ANOTHER AREA OF ARCTIC HIGH PRESSURE BUILDS
OUT OF CANADA AND SPREADS ACROSS THE NRN PLAINS AND UPPER GREAT
LAKES. THE FRONT OVER THE SRN PORTIONS OF THE LAKE WILL WASH OUT AS
A DOUBLE BARRELED LOW PRESSURE SYSTEM DEVELOPS OVER THE SRN AND
CNTRL PLAINS. THE COMPLEX LOW PRESSURE SYSTEM WILL TRACK EWD THIS
EVENING WITH ONE CIRCULATION CENTER TRACKING THROUGH CNTRL IL AND
ANOTHER TRACKING THROUGH THE LOWER MISSISSIPPI VALLEY. A WEAK
INVERTED SFC TROUGH AXIS ASSOCIATED WITH THE MORE NORTHERN OF THE
TWO LOWS WILL MOVE ACROSS THE LAKE EARLY TOMORROW. AS THE HIGH
BUILDS ACROSS THE UPPER GREAT LAKES THIS EVENING...WINDS OVER THE
ENTIRE LAKE WILL GRADUALLY TURN EASTERLY...BUT AS THE INVERTED
TROUGH AXIS CROSSES THE LAKE TOMORROW...WINDS OVER THE LAKE WILL
GRADUALLY BACK THROUGH NELY TO NORTHERLY TOMORROW EVENING AND THEN
THEN CONTINUE TO BACK TO NWLY BY LATE SATURDAY NIGHT AND EARLY
SUNDAY MORNING. AS COLDER AIR ASSOCIATED WITH THE ARCTIC HIGH IS
DRAWN OVER THE LAKE...THE STRONG COLD ADVECTION AND STRENGTHENING
PRESSURE GRADIENT WILL LEAD TO WINDS INCREASING TO AROUND 30KT
THROUGH THE DAY ON SUNDAY. WHILE GALES ARE NOT EXPECTED AT THIS
TIME...THE STRONG WINDS AND COLDER AIR WILL LEAD TO A CHANCE FOR
LIGHT TO MODERATE FREEZING SPRAY ON SUNDAY. THE BRISK NWLY WINDS
WILL PERSIST THROUGH SUNDAY NIGHT...AND THEN ANOTHER HIGH WILL BUILD
ACROSS LAKE MICHIGAN ON MONDAY...ALLOWING WINDS TO TEMPORARILY
SUBSIDE. AS THE HIGH MOVES OFF TO THE EAST ON TUESDAY...ANOTHER LOW
WILL TRACK ACROSS SCNTRL CANADA...LEADING TO INCREASING SWLY-WLY
WINDS BY TUESDAY...WHICH SHOULD PERSIST THROUGH THE MIDDLE OF NEXT
WEEK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ033-ILZ039 UNTIL NOON SATURDAY.
WINTER WEATHER ADVISORY...ILZ019-ILZ021-ILZ022-ILZ023-ILZ032
UNTIL NOON SATURDAY.
WINTER WEATHER ADVISORY...ILZ014...10 PM FRIDAY TO 6 PM SATURDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002 UNTIL NOON SATURDAY.
WINTER STORM WARNING...INZ010-INZ011-INZ019 UNTIL NOON SATURDAY.
LM...SMALL CRAFT ADVISORY...LMZ740...MIDNIGHT SATURDAY TO 3 PM
SATURDAY.
SMALL CRAFT ADVISORY...LMZ741-LMZ742-LMZ743...3 AM SATURDAY TO 3
PM SATURDAY.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
516 PM CST Fri Dec 13 2013
.DISCUSSION...
ISSUED 205 PM CST Fri Dec 13 2013
Clouds continue to lower and thicken this afternoon ahead of the winter
storm system expected to affect our area tonight into Saturday. Already
seeing some light rain and sleet pushing into extreme southwest IL early
this afternoon as the upper level wave tracks across the southern Plains.
SHORT TERM...Tonight through Monday
Significant snowfall expected over parts of central through east
central Illinois tonight thru Saturday morning...but not much in
the way of strong winds with this particular storm system.
The main forecast challenge this period will be with snowfall totals
starting tonight thru early Saturday afternoon. Will continue to hold
on to the winter weather advisory with a few locations across central
thru east central Illinois edging close to 6 inches by the time the
snow tapers off to flurries Saturday afternoon. Forecast soundings,
at least for a few hours late this afternoon into early this evening,
continues to suggest a brief period of rain, sleet and possibly some
freezing rain over parts of west central Illinois before we see the
lower layers saturate and cool sufficiently enough to support mostly
snow thru the overnight hours. NAM-WRF time height cross sections
indicate the best forcing coupled with the deeper moisture/and dendritic
growth zone will be mainly tonight thru about 14z Saturday. Using a
13:1 SLR indicates 4 to 6 inches will be common across the area by the
time the snow diminishes on Saturday.
Still a bit concerned about the potential for banding, especially
along the inverted trof, which is expected to push across our area
early Saturday morning. Several of the hi-res models suggest the
threat is there but unfortunately, are not very consistent in depicting
the location. Past few runs of the HRRR have indicated one band to move
north across the area this evening, with a break over parts of central
thru east central IL around midnight, before another band pushes
acrs the area towards morning with the inverted trof. Wouldn`t at all
be surprised to see a few areas with 6 to 8 inches accumulation by late
Saturday morning, but at this time, the threat appears too isolated.
Models are a bit more consistent in showing an increase in snow totals
just to our east as the weak surface low and inverted trof shift off
to our east and we see a better coupled 250mb jet structure and
associated upper level divergence.
The upper level wave and surface reflection should push well off
to our east by late tomorrow afternoon with all of the precip shifting
out of the forecast area. The weather should be on the quiet side for
the rest of the short term period with a brief cool down in the wake
of the winter system Saturday night through Sunday night before we see
milder temperatures move into our area early next week.
LONG TERM...Tuesday through Friday
Medium range models indicate some fast moving waves approaching
our area from the northwest at the start of this forecast period
with little in the way of moisture available to produce much in
the way of precip in our area. The first such wave will move across
the lower Great Lakes on Monday with a hint for some very light
precip during the day, mainly to our north. The next wave moves
quickly southeast along the tight 850 mb baroclinic zone on Tue,
at least according to the latest ECMWF, with again little in the
way of moisture to work with. Will continue to keep the first part
of the week dry but could see some low chance pops added in later
forecasts.
Warmer temperatures expected in the Wed-Fri time frame as a deep
upper level trof drops southeast into the southern Rockies and
brings about a strong southwest flow aloft over our area. This
should result in mild temps, at least compared to what we have
been experiencing, through the end of the week. However, as the
deep upper level trof edges east into the central Plains, a strong
Arctic cold front will approach our area on Friday increasing the
precip chances Thursday night into Friday, followed by much colder
weather for next weekend.
Smith
&&
.AVIATION...
ISSUED 515 PM CST Fri Dec 13 2013
With wet bulb zero below freezing, temperatures have dived as pcpn
began. All terminals have either started as snow or quickly
transitioned to snow. High res models suggest that vsbys will be
quite variable this evening with potential banding and lulls. Will
have to be quite general with timing. They do suggest a let up
along and east of I-55 after 04z before next wave comes in after
06z. Surface low should push east of Illinois by late morning
Saturday ending chances of measureable snow. A few flurries may
linger until main short wave axis moves through Illinois around 00z.
Warm front is set up just north of TAF sites and should move
little until surface low pushes through. This should keep winds
100-170 degrees until after 12z. once the low pushes east of the
terminals, winds will shift to 310-360 and pick up slightly.
However, gradient is rather weak for a winter storm and wind
speeds of 5-10 kts extent are expected prior to the surface low
with 5-15 kts after the shift.
Barker
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until Noon CST Saturday FOR ILZ038-
042>046-051>057-061>063-066>068-071>073.
WINTER WEATHER ADVISORY until 6 AM CST Saturday FOR ILZ027>031-
036-037-040-041-047>050.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
327 PM EST THU DEC 12 2013
.SYNOPSIS...
ISSUED AT 330 PM EST THU DEC 12 2013
HIGH PRESSURE WILL BE OVER THE REGION TONIGHT BUT TEMPERATURES
WILL NOT BE AS COLD AS LAST NIGHT. LOWS WILL STILL DROP INTO THE
LOWER AND MIDDLE TEENS...WITH A FEW SINGLE DIGITS POSSIBLE IN
RURAL AREAS. CLOUDS WILL INCREASE FRIDAY AHEAD OF A STRONG LOW
PRESSURE SYSTEM WHICH WILL BRING ACCUMULATING SNOW TO THE REGION
FRIDAY NIGHT AND SATURDAY. CURRENT INDICATIONS ARE THAT
ACCUMULATIONS BETWEEN 2 AND 5 INCHES WILL BE LIKELY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 323 PM EST THU DEC 12 2013
FEW CONCERNS THROUGH THE SHORT TERM PERIOD AS SIGNIFICANT WEATHER
AHEAD OF NEXT SYSTEM WILL HOLD OFF UNTIL FRIDAY NIGHT.
SATELLITE SHOWING MID AND HIGH CLOUDS EXITING SOUTHERN AREAS THIS
AFTERNOON WHILE THERMAL TROUGH SAGGING ACROSS LAKE MICHIGAN WAS
AIDING IN STRATOCU DEVELOPMENT ACROSS BERRIEN AND CASS COUNTIES IN
MICHIGAN. THESE LOW CLOUDS AND ANY LAKE EFFECT SNOW SHOWERS WILL BE
MAIN CHALLENGE TONIGHT. SYNOPTIC SCALE THERMAL TROUGH ALREADY MOVING
EAST BUT LAKE INDUCED TROUGHINESS AND THERMAL DISPARITY PROGGED TO
ONLY SLOWLY WARM OVERNIGHT. SATELLITE ALREADY SHOWING LAKE CLOUDS
INTO NORTHERN BERRIEN COUNTY DESPITE WARM AIR ADVECTION. HIRES
GUIDANCE SUGGEST TRAJECTORIES AND WEAK LAKE AGGREGATE TROUGH MAY
ALLOW CLOUDS TO STREAM ACROSS MICHIGAN COUNTIES THIS EVENING AND
INTO OVERNIGHT HOURS. PREVIOUS SKY COVER GRIDS HAD THIS TREND
HANDLED WELL AND GENERALLY STAYED WITH SIMILAR IDEA. LIGHT SNOW
SHOWERS ALREADY NEAR OR INTO EXTREME NORTHERN TIP OF BERRIEN COUNTY
SO WILL CARRY SCT FLURRIES OR LIGHT SNOW SHOWERS THROUGH THE EVENING
UNTIL WARMER AIR ARRIVES AND FLOW WEAKENS WHICH COULD LEAD TO WEAK
MESOLOW FORMATION OVER BOWL REGION OF LAKE. LITTLE OR NO
ACCUMULATION EXPECTED GIVEN SHALLOW MOISTURE DEPTH IN OUR AREA.
OTHERWISE EXPECT MOSTLY CLEAR SKIES TO START THE EVENING WITH SOME
MID AND HIGH CLOUDS INCREASING LATE.
NAM MODEL SOUNDINGS QUITE BULLISH ON LOW LEVEL MOISTURE AND STRATUS
DEVELOPMENT FRIDAY MORNING. NAM12 HAS BEEN RATHER
AGGRESSIVE WITH THIS IDEA THIS WINTER WITH SEVERAL INSTANCES SHOWING
THIS WITH LITTLE TO NO DEVELOPMENT. LATEST HRRR GIVES SOME CREDENCE
TO THIS SOLUTION IN THE NORTH NEAR WEAK SURFACE BOUNDARY WHERE WINDS
BECOME LIGHT. HAVE SLOWLY INCREASED CLOUDS ACROSS THE NORTH
AND NORTHWEST WITH POTENTIAL FOR SOME MID AND HIGH CLOUDS AS WELL.
THIS SHOULD KEEP TEMPS FROM FALLING TOO MUCH OVERNIGHT WITH WARM AIR
ADVECTION WELL UNDERWAY. LOOKING FOR LOWS IN THE 10 TO 15 DEGREE
RANGE LATE EVENING WITH STEADY OR EVEN SLOWLY RISING TEMPS LATE WITH
ANY CLOUD COVER DEVELOPMENT.
COL AREA ASSOCIATED WITH WEAK BOUNDARY WILL LIE ACROSS NW FORECAST
AREA FRIDAY WITH GENERALLY LIGHT WINDS. CLOUD COVER REMAINS TRICKY
DEPENDING ON HOW MUCH SATURATION OCCURS NEAR BOUNDARY WITH INVERSION
ALOFT COURTESY OF WARM AIR ADVECTION. HIGHS WILL REACH MID TO UPPER
20S MOST AREAS WITH LOW 30S POSSIBLE FAR SOUTHWEST AHEAD OF NEXT
STRONG SHORT WAVE. BULK OF PCPN WILL HOLD OFF UNTIL FRIDAY EVENING
BUT DID ALLOW A SLIGHT CHANCE TO RESIDE FAR SOUTHWEST AFTER 21Z WITH
PROXIMITY OF INCREASING MOISTURE AND ISENTROPIC LIFT.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 323 PM EST THU DEC 12 2013
...ACCUMULATING SNOWFALL FRIDAY NIGHT-SATURDAY...
PATTERN IS STILL SUPPORTIVE OF FAVORABLE SYNOPTIC SCALE SNOW EVENT
FOR THE REGION BEGINNING LATE FRIDAY NIGHT AND CONTINUING INTO THE
DAY SATURDAY.
NORTHERN STREAM FLOW WILL KEEP THE BOUNDARY LAYER COLD AIR IN PLACE
AND DEEP ENOUGH TO FAVOR ALL SNOW FOR THE EVENT. THE CHALLENGE WILL
BE TIMING THE PHASING OF THE SOUTHERN STREAM AND NORTHERN STREAM
SHORTWAVES ACROSS THE GREAT LAKES.
12Z RUNS ARE GENERALLY CONSISTENT WITH THE SURFACE LOW DEEPENING IN
THE PANHANDLE REGION DURING THE DAY FRIDAY. CONTINUED DEEPENING AND
OF THE SURFACE LOW OVER THE SORUTHERN PLAINS AND LOWER MISSISSIPPI
RIVER VALLEY DURING THE EVENING FRIDAY INTO SATURDAY WILL USHER IN
COPIOUS MOISTURE AND EXPECT TO SEE A PRONOUNCED WARM LAYER SPREADING
NORTHWARD. THIS WILL FAVOR A MORE DENSE AND WET SNOW ACROSS THE
SOUTH.
TIMING AND PHASING OF THE SOUTHERN AND NORTHERN STREAM WILL
CRITICALLY AFFECT THE DURARTION OF THE SNOW AND EXPECT THAT THERE
WILL BE A RAPID CUTOFF OF PRECIPITATION EARLY SATURDAY.
SNOWFALL WILL BE HEAVIEST AND WETTER SOUTH OF THE CWFA AND DRIER
NORTH. REGARDLESS EXPECT TO SEE UPWARDS OF 5 INCHES ACROSS MOST OF
THE AREA.
AS THE SYNOPTIC DRIVEN SNOW ENDS...LAKE EFFECT SHOULD CONTINUE IN
LAPORTE...ST. JOSEPH...BERRIEN AND CASS COUNTIES FOR AN ADDITIONAL 2
TO 4 INCHES BY SATURDAY NIGHT EARLY SUNDAY MORNING.
COLDER AND DRIER AIR WILL SETTLE ACROSS THE PLAINS SUNDAY AND WITH
NEW SNOW AND SOME CLEARING...TEMPERATURES SHOULD BOTTOM OUT AGAIN
SUNDAY NIGHT/MONDAY MORNING. WILL BE MAKING SOME DOWNWARD
ADJUSTMENTS TO THE TEMPERATURES FOR SUN/MON PERIOD.
NEXT CLIPPER SYSTEM FORMS IN THE GREAT LAKES REGION MONNDAY/MONDAY
NIGHT/TUESDAY AND THIS WILL BRING AN INCREASE OF CLOUDS AND LAKE
EFFECT TO THE AREA. TIMING AND DURATION OF SNOWFALL IS TOO FAR OUT
TO MAKE DEFINITIVE AMOUNT FORECASTS...BUT IT WILL ADD TO THE SNOW
ALREADY ON THE GROUND. AS THAT SYSTEM EXITS...THE COLD AIR RETURNS
IN ITS WAKE. STARTING TO SEE A DECENT SNOW PACK OVER THE NRN
PLAINS...ADDING TO THE DOUBT THAT ANY SIZABLE WARMUP IS COMING OUR
WAY.
NEXT STORY ON THE HORIZON...ECMWF PREDICTION OF DEEP AND EXPLOSIVE
CYCLOGENSIS ACROSS THE NORTHERN AND CENTRAL PLAINS WEDNESDAY NIGHT
INTO THURSDAY. THERE ARE HINTS IN THE OTHER LONG RANGE MODELS OF A
WAVE EJECTING THROUGH THE ROCKIES. THIS WILL HAVE TO BE WATCHED AS
THE PATTERN EVOLVES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1247 PM EST THU DEC 12 2013
VFR CONDITIONS TO START THE PERIOD WITH SOME UNCERTAINTY
REGARDING CIGS TONIGHT AND FRIDAY MORNING. MID AND HIGH CLOUDS
GRADUALLY MOVING OFF TO SOUTHEAST WITH PARTIAL CLEARING OCCURING
AT TAF SITES EARLY THIS AFTERNOON. LAKE CLOUDS SEEN ON SATELLITE
DROPPING SOUTH TOWARD KBEH AT 1730Z WITHIN THERMAL TROUGH. THIS
TROUGH NOT PROGGED TO REACH KSBN AS IT SLOWLY MIGRATES EAST.
HOWEVER...LOW LEVEL WIND FIELD BECOMES WNW FOR A PERIOD WHICH MAY
ALLOW CLOUDS TO DRIFT TOWARD KSBN. MODEL SOUNDINGS ALSO SHOWING
INCREASING LOW LEVEL MOISTURE AROUND 00Z WITH THESE TRAJECTORIES.
FOR NOW DO NOT HAVE ENOUGH CONFIDENCE FOR MVFR OR IFR CONDITIONS
AT KSBN OVERNIGHT SO STAYED VFR WITH INTRODUCTION OF SOME SCT015
CLOUDS. WEAK FRONTAL BOUNDARY TO SAG NEAR KSBN FRI AM WITH WEAK
WINDS AND MOISTURE TRAPPED BENEATH INVERSION WITH WARM AIR
ADVECTION ALOFT. THIS LEADS TO A LITTLE HIGHER CONFIDENCE IN MVFR
CIGS DEVELOPING DURING THE DAY ALONG WITH MODEL GUIDANCE SO ADDED
MVFR CONDITIONS. KFWA TO REMAIN VFR THROUGH THIS PERIOD WITH
DETERIORATING CONDITIONS EXPECTED LATER FRIDAY AND ESPECIALLY
FRIDAY NIGHT ALL AREAS WITH SNOW DEVELOPING.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ043-046.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...LEWIS
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS DODGE CITY KS
507 PM CST Fri Dec 13 2013
...Updated aviation discussion...
.SHORT TERM...(This evening through Saturday)
ISSUED AT 344 PM CST FRI DEC 13 2013
Sensible weather will be fairly quiet tonight and Saturday as the
storm system to our south will continue to pull away from the
Central/Southern Plains. For tonight, surface winds will stay up in
the 13 to 18 knot range, and this will prevent a substantial drop in
temperatures as the boundary layer remains somewhat mixed. Low
temperatures in the lower 20s look good. The wind will provide a
little bite overnight, with wind chill values down into the single
digits. For Saturday, north winds will continue, even though the
MSLP gradient will relax. The height gradient in the lower
troposphere off the surface will still be fairly strong, so
insolation will provide necessary mixing to keep winds in the 14 to
19 knot range through much of the day out of the north-northwest. As
far as temperatures go on Saturday, since there will not be any
advection of fresh arctic (or even polar) air, temperatures will
have no problem warming back up into the lower to mid 40s most
everywhere. Cooler temperatures will be found from Hays to Medicine
Lodge with warmer temps around 47 or 48 closer to the Colorado
border.
.LONG TERM...(Saturday night through Friday)
ISSUED AT 344 PM CST FRI DEC 13 2013
Over the next week, an upper level trough over the Arctic Ocean will
rotate around the polar vortex and eventually track across the
northern plains by late next week. Meanwhile, an upper trough will
move from the eastern Pacific into the desert southwest and northern
Mexico. As this pattern evolves, dry northwesterly mid to high level
flow will prevail through Tuesday across the western and central
United States, then becoming more west-northwesterly and westerly by
Wednesday and Thursday. The surface pressure gradient will stay
rather weak through Tuesday, resulting in fairly light winds. But
the stronger zonal component to the mid level winds will result in a
stronger lee trough by Wednesday, with some low level warming.
However, the models are advertising increasing high level cloud by
Wednesday as well, which may prevent vertical mixing and surface
warming. But some 60s are certainly possible for Wednesday
or Thursday. Temperatures will be above average through Thursday,
but generally within 1 standard deviation from climatology (highs
mainly upper 40s to near 60F with lows in the 20s and 30s).
After Thursday, the aforementioned upper level trough progressing
across the northern plains will drag some arctic air into Kansas by
Thursday evening and Friday. It is very unclear how much impact the
southern stream trough over the desert southwest will have on our
weather besides an increase in cloud by Friday and possible light
snow. However, given the lack of phasing of the northern plains
and desert southwest troughs in the models, we are leaning
towards a very minor snow event. High temperatures should fall to 1
to 2 standard deviations below climatology (20s) by Friday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 506 PM CST FRI DEC 13 2013
Gusty north winds at 15 to near 20kts will develop behind a cold
front as it crosses southwest Kansas overnight. VFR conditions are
expected through midnight, however 18z NAM BUFR soundings and
latest HRRR indicated low MVFR or even IFR cigs behind the cold
front will spread across southwest Kansas after 06z. As of 22z a
few surface observations in northeast Nebraska were reporting cigs
in the 500ft to 1500ft AGL range behind this front so will trend
in the direction of the latest HRRR and 18z BUFR soundings. Will
introduce low MVFR and/or IFR cigs and gusty winds in the HYS area
around 04z and then at DDC and GCK between 07z and 10z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 21 44 23 54 / 0 0 0 0
GCK 20 46 21 53 / 0 0 0 0
EHA 23 46 24 53 / 0 0 0 0
LBL 22 46 24 54 / 0 0 0 0
HYS 17 40 22 53 / 10 0 0 0
P28 22 41 25 54 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Umscheid
LONG TERM...Finch
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS GOODLAND KS
953 PM MST WED DEC 11 2013
.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 1258 PM MST WED DEC 11 2013
LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW NW FLOW STILL IN
PLACE FROM THE NORTHERN ROCKIES AND ACROSS THE CENTRAL PLAINS...WITH
A SHORTWAVE RIDGE ACROSS THE SW US. AT THE SURFACE 1037MB SURFACE
HIGH PRESSURE ENTERED OVER NORTHEASTERN KS AND SOUTHEASTERN NEBRASKA
WITH A LEE TROUGH JUST EAST OF THE FRONT RANGE IN COLORADO. SOUTH TO
SOUTHWEST GRADIENT BETWEEN THESE FEATURES IS IN PLACE OVER OUR
CWA...WHICH HAS SUPPORTED WAA ACROSS WESTERN LOCATIONS AND ABOVE
FREEZING TEMPERATURES ALONG THE CO/KS STATE LINE.
LOW CLOUDS HAVE PRETTY MUCH CLEARED ACROSS ALL BUT THE FAR
NORTHEAST...AND THESE CLOUDS SHOULD CONTINUE TO DISSIPATE AND MOVE
EAST OUT OF THE AREA. WITH SHORTWAVE RIDGING BUILDING NORTH AND EAST
WE WILL SEE DRY CONDITIONS PERSIST. THE MAIN FORECAST CHALLENGE
THROUGH THE SHORT TERM WILL BE HOW WARM TO MAKE TEMPS. AIR MASS WILL
CONTINUE TO MODERATE WITH SW FLOW SUPPORTING GOOD WAA. MODELS SHOW
H85 TEMPS IN THE 5-7C RANGE...WHICH IF THE GOOD MIXING/WARMING
OBSERVED THE LAST FEW DAYS IS ANY INDICATION WE SHOULD SEE HIGHS AT
LEAST IN THE LOW 50S OVER SNOW FREE AREAS. WITH SW WINDS ADVECTING
THESE WARMER TEMPS TOWARDS SNOW COVERED LOCATIONS IN OUR FAR WEST
AND NORTHEAST WE SHOULD SEE CONTINUED DETERIORATION OF THE SNOW
PACK. I AM NOT AS CONFIDENT ABOUT HIGH TEMP ON THURSDAY OVER
MCCOOK/ATWOOD/OBERLIN...BECAUSE OF THIS SNOW PACK. I WOULD NOT BE
SURPRISED IF AFTER TOMORROW THERE IS NO SIGNIFICANT SNOW PACK LEFT
OVER OUR CWA EVEN IN LOCATIONS THAT SAW 4-5" IN THE NORTHEAST.
.LONG TERM...(THURSDAY NIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 1209 PM MST WED DEC 11 2013
SHORTWAVE TROUGH WILL MOVE ACROSS THE SOUTHERN PLAINS THURSDAY
NIGHT AND FRIDAY. THE SYSTEM WILL BE TOO FAR SOUTH TO BRING A
CHANCE OF PRECIPITATION TO THE LOCAL AREA...HOWEVER IT WILL TAP
INTO SOME SLIGHTLY COOLER AIR FOR FRIDAY AND SATURDAY...WITH
TEMPERATURES 5 TO 10 DEGREES BELOW NORMAL. THE REMAINDER OF THE
LONG TERM PERIOD WILL SEE VARYING DEGREES OF NORTHWEST FLOW ALOFT.
NO PRECIPITATION IS EXPECTED. TEMPERATURES WILL BE MILD WITH HIGHS
MAINLY IN THE 50S THOUGH COULD REACH THE 60S AND POSSIBLY EVEN 70S
IN A FEW LOCATIONS TUESDAY AND WEDNESDAY WITH DOWNSLOPE WARMING.
HOWEVER...ANOTHER ARCTIC OUTBREAK IS LOOMING FOR THE END OF THE
WEEK WITH BITTERLY COLD AIR MASS UPSTREAM WHICH WILL ARRIVE JUST
BEYOND THIS FORECAST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 953 PM MST WED DEC 11 2013
VFR CONDITIONS WILL CONTINUE. SOUTHWEST WINDS OF 10 KNOTS OR LESS
CAN BE EXPECTED THROUGH THE FORECAST PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
957 PM EST Fri Dec 13 2013
...Forecast Update...
Issued at 955 PM EST Fri Dec 13 2013
That first wave of light to moderate precip (though the flakes at
times were large) that came through has helped to raise dewpoints
quite a bit, and they have stayed that way a couple of hours now
with upstream locations not dropping too much. Forecast soundings
from the models look like they are overdoing the dry air that was
supposed to follow that wave, though the RUC does keep higher
dewpoint air over us now. Given these changes, think the rain/snow
transition line can be moved north. Have adjusted the forecast as
such and now have snow totals of 1-2 inches only over my northern
stripe of counties as well as the northern parts of Perry and
Crawford. Thus have cancelled the advisory south of this line. Will
keep in a special weather statement for a mix of precip south of
that advisory.
Issued at 600 PM EST Fri Dec 13 2013
Seeing a NW/SE-oriented band of precipitation well out ahead of the
main rainmake for tonight. Several of the high-res models have
picked up on this band and then bring a quiet weather period behind
it for a few hours. Have adjusted our pop grids to match this trend
and to account for the earlier onset. Have had several PING reports
of snow coming out of that band and the ob at KOWB indicated a
rain/snow mix. Soundings indicate the dry air in the low levels is
helping to bring temperatures down quickly as this precipitation
falls into it. Temps over our area now are around 40, but within the
band over PAH`s area they have fallen to 34. Updated forecast will
be out shortly.
.SHORT TERM (Now through Saturday Night)...
Issued at 305 PM EST Fri Dec 13 2013
...A ROUND OF WINTERY WEATHER TONIGHT WITH LIGHT SNOW ACCUMULATIONS
ACROSS SOUTHERN INDIANA...
In the near term, mid-high level cloud cover is quickly
overspreading the region. Skies were partly to mostly cloudy and
with a southerly wind flow, temperatures have warmed into the 40s
across Kentucky with middle to upper 30s across southern Indiana.
We expect cloudy skies to persist for the rest of the afternoon and
into the early evening with temperatures falling back into the lower
30s across southern Indiana and into the middle-upper 30s in KY.
Latest model data continues to have pretty good continuity from
previous data sets. The models all indicate that an area of low
pressure over eastern TX will continue to deepen and head
northeastward through the heart of the Ohio Valley during the short
term forecast period. A large batch of precipitation will accompany
this feature and begin to overspread the region tonight. With
surface temperatures dropping to near the freezing mark, this will
bring a mixed bag of wintry weather to the area tonight...followed
by a cold rain for Saturday and then a transition back to snow
Saturday night as colder air moves into the region.
As precipitation moves eastward toward the region this evening, it
will encounter a relatively dry airmass that is in place. This can
easily be seen in the 12Z BNA and ILN sounding data. Precipitation
aloft will move into the region and begin to saturate the column
from top to bottom. Given the scope of isentropic lift and synoptic
scale ascent ahead of this system, it appears that it will take an
hour or two for the column to saturate down. With this top to
bottom saturation, we will see evaporative cooling effects in which
the lower atmosphere...while initially warm will cool to an extent
this evening. Thus, the initial precipitation developing across the
region looks to be in the form of rain with some sleet at the
onset. A mix of rain/sleet/snow is likely in areas north of the
river at onset due to a cooler atmospheric profile that is expected
to be in place.
As the evening wears on, we will see the rain/sleet mixture change
over to mainly a snow/sleet mixture across the northern half of
Kentucky and all of southern Indiana. Thermal profiles across
southern Kentucky suggest that rain will likely be the main
precipitation type...especially in areas south of a line from
Hartford to around Richmond, KY. As we head into the overnight
hours, we expect a snow/sleet mixture to continue across northern KY
with mainly snow and some sleet across southern Indiana.
Temperatures north of the BG/WK parkways look to cool into the lower
30s. Probably will see temperatures cool to around 32-34, but in
heavier bursts of precipitation that fall as snow, temperatures in
localized areas could drop to 29-30. As we head toward sunrise, all
of the available guidance suggests that low-level warm air advection
will push further northward into KY changing the sleet/snow mixture
over to plain rain. Only areas that look to remain snow by sunrise
would be along and north of the I-64 corridor into southern Indiana.
Low-level warm air advection is expected to continue into the day on
Saturday with most areas going over to cold rain during the day.
This low-level warm nose looks to push northward into southern
Indiana resulting in an eventual change over to mostly rain even
that far north. Precipitation will pull on off to the northeast as
the low-pressure system heads into New England. As this occurs,
colder air will be pulled back down into the region Saturday night.
This will result in any left over precipitation changing over to
light snow. However...model soundings do show a loss of substantial
moisture in the dendritic ice crystal layer so we could see more of
light freezing drizzle falling across much of the region Saturday
night despite having a large cold low-level airmass in place.
As mentioned above, temperatures tonight are expected to fall to
around 30 in areas north of the Ohio River. Areas south of the Ohio
River and north of the WK/BG Pkys should cool into the 32-34 degree
range. Areas south of the Parkways look to cool into the 34-36
degree range. Highs on Saturday look to warm into the 40s across KY
with middle 30s in southern Indiana. Lows Saturday night will drop
back into the 20s in all areas.
With regards to snowfall amounts, we continue to believe the area at
most risk for snowfall accumulation overnight will be in areas of
southern Indiana north of the I-64 corridor. Along the I-64
corridor we expect around an inch or two of snow accumulation. In
our northern row of counties (along/north of a Jasper to Deputy
line) two to three inches of snowfall will be possible. For this
reason, we will continue the Winter Weather Advisory for tonight and
into Saturday morning.
In areas south of the Ohio River...but north of the WK/BG Pkys,
snowfall accumulation will be substantially less due to the expected
wintry mixture and warmer surface temperatures. Generally think
that a coating to maybe a half inch will be possible along and north
of the BG/WK Parkways with a half to 1 inch possible up near the
I-64 corridor to near the Ohio River. In general, expect most
snowfall accumulations in this area will be mainly on grassy and
elevated surfaces, but some accumulation on roads will be possible
during heavier precipitation periods. Very little snow accumulation
is expected across south-central Kentucky as precipitation will
remain in the form of a cold rain.
Some minor snow accumulations are possible late Saturday night if
the colder air gets into the region more quickly than forecast and
if precipitation is slower to move out. The combination of wet
roads and falling temperatures made lead to slick spots developing
late Saturday night. We plan on addressing those concerns in the
Hazardous Weather Outlook product.
.LONG TERM (Sunday through Friday)...
Issued at 305 PM EST Fri Dec 13 2013
A dry northwesterly flow at 500mb will develop late Sunday in the
wake of Saturday`s system, which is forecast to deepen off the New
England Coast early Monday. With a broad cyclonic flow centered over
the Great Lakes, a couple of weak upper disturbances will rotate
through the northern Ohio Valley over the first several days of next
week. However any light snow or snow showers will likely stay
confined to northern Indiana and Ohio. The first feature may bring
light flurries late Monday as for south as southern Indiana. Our
second feature seems timed for late Tuesday, with only some variable
cloudiness associated with this feature.
Temperatures will tend to moderate through the week, but slowly at
first as warmer air across the southern plains will stay shunted to
our southwest by the Great Lakes longwave trough. High temperatures
Tuesday will rise around 5 to 8 degrees above Monday`s expected
highs in the Lower 40s. A weak frontal passage will cool down
Wednesday just a bit as high pressure builds overhead.
Monday and Tuesday will feature variably cloudy skies, as the
combination of residual low level moisture and upper level waves
will likely bring a few cloudy periods. Mostly clear skies
anticipated for Wednesday.
Mild temperatures will finally return for Thursday and Friday, and
possibly Saturday as well. A digging jet streak along the west coast
late Wednesday will act to amplify a trough over the Rockies by late
Thursday, in turn leading to cyclogenesis across the plains. Robust
southwesterly flow will develop across the Lower Ohio Valley by
Thursday, continuing Friday. Initially, on Thursday, recycled
continental air will lead to mostly clear skies. Eventually, Gulf
moisture will return by Friday into early Saturday, bringing very
mild temperatures and a potential for quite a bit of rain early next
weekend. Highs Thursday and especially Friday will reach the 50s.
&&
.AVIATION (00Z TAF Update)...
Updated at 630 PM EST Fri Dec 13 2013
Complicated TAF package, with a wintry mix of precip forecast as low
pressure over OK tonight moves into the Tennessee Valley Saturday
and then east of the region late in the period. First off we have a
band of precip oriented NW/SE and approaching SDF this hour, LEX the
next. Have had some rain/snow mix out of this band, with KEVV being
all snow with IFR visibilities. It looks like this band will
persist, enough to warrant IFR visibilities at KSDF with a
rain/snow/sleet mix. The band should weaken some as it nears KLEX,
given the amount of dry air it has to work across to get there, so
have MVFR conditions there.
There should be a pause in the precip behind this band for a few
hours. Then should see a rain/snow mix the rest of the night at
KSDF/KLEX and all rain at KBWG. Ceilings will drop as this rain
comes in, going down at least to IFR levels at some point in the
morning. These conditions will persist through Saturday. Colder air
will move in behind northwest winds Saturday evening, and may bring
a round of light snow/drizzle/freezing drizzle. For now have
maintained MVFR vsby and IFR cigs at KSDF and no mention of frozen
stuff, given low confidence in how much moisture will be around by
then.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...WINTER WEATHER ADVISORY until 10 AM EST /9 AM CST/ Saturday FOR
INZ076>079-083-084-089.
&&
$$
Updates........RJS
Short Term.....MJ
Long Term......JSD
Aviation.......RJS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1011 PM EST FRI DEC 13 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 325 PM EST FRI DEC 13 2013
WIDESPREAD SNOW WILL DEVELOP TONIGHT AND CONTINUE ALL DAY SATURDAY
AS A LOW PRESSURE SYSTEM MOVES THROUGH THE OHIO VALLEY. MORE LAKE
EFFECT SNOW SHOWERS ARE LIKELY ON SUNDAY BEHIND THIS SYSTEM.
&&
.UPDATE...
ISSUED AT 1011 PM EST FRI DEC 13 2013
THE FGEN FORCING HAS FAILED TO PRODUCE MUCH SNOW EARLY THIS
EVENING. HOWEVER THAT WAS CHANGING AS RACINE WI RECENTLY WENT DOWN
TO 1.25 MILES IN SNOW IN THE DEVELOPING BAND. EXPECT SNOW WILL
EXPAND ACROSS MOST OF THE CWA BETWEEN NOW AND 06Z. WINDS WERE
ALREADY KICKING UP AND WILL ADD TO THE TRAVEL ISSUES INTO THE
OVERNIGHT PERIOD...PRODUCING BLOWING AND DRIFTING.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 325 PM EST FRI DEC 13 2013
LITTLE CHANGE TO THE GOING FORECAST AS LATEST MODEL GUIDANCE REMAINS
VERY CONSISTENT IN SHOWING A PROLONGED 24 HOUR SNOW EVENT WITH
WIDESPREAD 3 TO 5 INCH ACCUMULATIONS. THE LOWER END AMOUNTS ARE
EXPECTED TO BE AROUND LUDINGTON AND PENTWATER WHILE THE HIGHER
AMOUNTS SHOULD BE AROUND LAN AND JXN.
HOWEVER FGEN FORCING THROUGH THIS EVENT COULD LEAD TO NON
UNIFORM/VARIABLE STORM TOTAL ACCUMULATIONS ACROSS THE CWFA...WITH
LOCALLY HIGHER AMOUNTS WHERE NARROW FGEN BANDS SET UP AND PERSIST.
THE ADVISORY REMAINS UNCHANGED WITH THE 9 PM START TIME ALTHOUGH IT
COULD TAKE UNTIL WELL AFTER MIDNIGHT BEFORE THE SNOW BECOMES MORE
WIDESPREAD AND IS IMPACTING THE ENTIRE CWFA. THE BULK OF THE STORM
TOTAL SNOW WILL FALL ON SATURDAY. THIS EVENT FEATURES A DEEP BUT
HIGH DGZ CENTERED BETWEEN 7K AND 15K FEET WITH GENERALLY WEAK BUT
DEEP OMEGAS. SNOW RATIOS ARE EXPECTED TO BE ABOUT 15:1 AND THE SNOW
SHOULD HAVE A WETTER CONSISTENCY THAN RECENT EVENTS.
LATEST SHORT TERM HI RES MODEL GUIDANCE CONTINUES TO INDICATE A
STRONG POTENTIAL OF A NARROW WEST TO EAST ORIENTED BAND OF FGEN SNOW
DEVELOPING IN SRN LWR MI THIS EVENING WELL AHEAD OF THE MAIN SYSTEM
SNOW WHICH DOES NOT REALLY ARRIVE UNTIL WELL AFTER MIDNIGHT.
THIS FGEN BAND DEVELOPS NEAR OR JUST SOUTH OF THE I-96 CORRIDOR
BETWEEN 00Z AND 03Z AND CONTINUES THROUGH 06Z-09Z BEFORE BEING
ABSORBED IN WITH THE MORE BROAD/WIDESPREAD SYSTEM SNOW LATE TONIGHT.
BEST ATTEMPT AT PINPOINTING THE EXACT AREA IS A HOLLAND TO HASTINGS
TO CHARLOTTE TO MASON LINE... GIVE OR TAKE 25 MILES.
ANOTHER MESOSCALE ISSUE THAT MAY COME INTO PLAY EVENTUALLY IS EAST
FLOW LAKE ENHANCEMENT OFF LAKE HURON WHICH COULD LEAD TO LOCALLY
HIGHER AMOUNTS IN THE CLARE COUNTY AREA.
THE LAKE EFFECT SNOW EVENT FOR SUNDAY APPEARS TO HAVE RELATIVELY
SHALLOW MOISTURE WITH INVERSION HEIGHTS AROUND 5K FEET. HOWEVER THE
DGZ IS 3-5K FT DEEP AND IN THE CLOUD LAYER SO SOME DECENT SNOW
SHOWERS CAN STILL BE EXPECTED. LOW LEVEL FLOW WILL BE WEST NORTHWEST
AND 15 TO 25 KTS... SO THE SNOW SHOWERS SHOULD CARRY WELL INLAND.
ADDITIONAL ACCUMULATIONS OF 1 TO 4 INCHES ARE LIKELY ALONG AND WEST
OF HWY 131.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 325 PM EST FRI DEC 13 2013
THE BELOW AVERAGE TEMPERATURES AND UNSETTLED WEATHER PATTERN/LAKE
EFFECT WILL CONTINUE TO AFFECT THE STATE INTO MID WEEK NEXT WEEK.
CONFIDENCE IS GROWING THAT WE SHOULD SEE AT LEAST A SHORT BREAK IN
THE COLD AIR.
MAX TEMPS IN THE 20S AND OCCASIONAL CHCS OF SNOW SHOWERS WILL EXIST
FROM THE BEGINNING OF THE LONG TERM THROUGH WED. WE WILL REMAIN
GENERALLY IN THE LONGER WAVE TROUGH WITH NW FLOW DURING THIS PERIOD.
THIS WILL BRING HARD TO TIME SHORT WAVES THROUGH THE AREA. ONSHORE
LOW LEVEL FLOW AND COLD AIR WILL KEEP LAKE EFFECT THREAT AROUND...
THAT WOULD BE ENHANCED BY ANY SHORT WAVES THAT DO COME THROUGH. THE
DETAILS WILL HAVE TO BE IRONED OUT AS WE GET CLOSER TO THAT PERIOD.
WE CONTINUE TO EXPECT A MODERATION IN TEMPS OF SOME DEGREE THEN FOR
THE END OF NEXT WEEK. THE MODERATION IN TEMPS WILL LIKELY BE
ACCOMPANIED BY MORE UNSETTLED WEATHER...WITH POSSIBLE RAIN AND/OR
SNOW. THE UPPER TROUGH OVER THIS REGION OF THE COUNTRY IS STILL
EXPECTED TO BE PUSHED OUT BY A STRONG UPPER JET DIVING IN FROM THE
SRN ALASKA COAST. WE WILL SEE THE FLOW TRANSITION FROM THE NW FLOW
EARLY IN THE WEEK TO SW FLOW LATE IN THE WEEK AFTER THE TROUGH IS
DUG ACROSS THE DESERT SW.
THE FIRST SYSTEM TO COME FROM THE WRN TROUGH WILL AFFECT THE AREA
LATE THU INTO FRI. DEPENDING ON HOW STRONG THIS ENDS UP...WILL BE
HOW WARM WE GET AND HOW MUCH OF A PCPN TRANSITION WE SEE. WE DO
EXPECT AT THIS TIME FOR RAIN TO BE A LIKELY P-TYPE WITH A GOOD CHC
OF TEMPS IN THE 40S. WE HAVE GONE WITH A MIX FOR NOW WITH
UNCERTAINTY STILL PRESENT. WE COULD SEE SOME POSSIBLE HYDRO ISSUES
WITH ICE JAMS AND/OR HIGH FLOWS IF ENOUGH WARM AIR AND RAIN COMES
IN. MUCH COLDER AIR WILL MOVE BACK IN BEYOND THE LONG TERM.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 626 PM EST FRI DEC 13 2013
THERE IS LITTLE QUESTION LIFT CONDITIONS WILL PREVAIL AT MOST IF
NOT ALL OF THE TAF SITES BY 12Z SATURDAY. THE QUESTION IS MORE
WHEN DOES THE SNOW MOVE IN.
CURRENTLY THE LOW CLOUDS HAVE CLEARED OUT OF ALL OF THE TAF SITES
AND I AM THINKING THEY WILL NOT RETURN UNTIL THE SNOW GETS
UNDERWAY. LOOKING AT RAP MODEL SOUNDING IT IS NOT UNTIL BTWN 06Z
AND 09Z THE SOUNDINGS GET MOIST ENOUGH FOR SNOW TO REACH THE
GROUND. ONCE THAT DOES HAPPEN THOUGH THERE WILL BE A FAIRLY LONG
PERIOD OF LIGHT TO MODERATE SNOW ACROSS THE AREA THAT WILL RESULT
IN SOLID LIFR CONDITIONS FROM SAY 09Z THROUGH 23Z TO 24Z.
THERE IS THE SUGGESTIONS IN THE MODELS THAT A BAND OF SNOW MAY
FORM BETWEEN I-94 AND I-96 BY 03Z. MY PROBLEM WITH PUTTING THAT
IN OUR TAFS IS THE AIR IS DRY FOR NEARLY 10000 FT BELOW THE CLOUD
BASE THAT WOULD BE PRODUCING THE SNOW. I HAVE TO WONDER HOW MUCH
OF THE SNOW WILL MAKE IT TO THE GROUND. SINCE AT 23Z NONE OF THE
OBSERVATIONS UNDER THE BAND OVER SOUTHERN WISCONSIN ARE MAKING IT
TO THE GROUND YET... I WAS CONSERVATIVE WITH THE START TIME OF THE
SNOW AND LARGELY USED THE RAP MODEL SHOWING NEAR SATURATED
SOUNDING TO PUT MY START TIMES IN THE TAFS.
&&
.MARINE...
ISSUED AT 325 PM EST FRI DEC 13 2013
EAST WINDS WILL INCREASE TONIGHT BUT WAVES WILL BE LOW DUE TO
OFFSHORE FLOW. NEXT ACTIVE PERIOD WILL BE LATE SATURDAY NIGHT AND
&&
.HYDROLOGY...
ISSUED AT 325 PM EST FRI DEC 13 2013
MOST OF THE RIVERS HAVE COMPLETELY ICED OVER WHICH MEANS THE ICE JAM
THREAT HAS DECREASED. IT STILL NEEDS TO BE WATCHED... ESPECIALLY
LATE NEXT WEEK WHEN A POTENTIAL WARM UP COULD BREAK UP THE ICE AND
CREATE MOVEMENT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 10 PM EST SATURDAY FOR MIZ037>040-
043>046-050>052-056>059-064>067-071>074.
LM...NONE.
&&
$$
UPDATE...JK
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...NJJ
AVIATION...WDM
HYDROLOGY...MEADE
MARINE...MEADE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
627 PM EST FRI DEC 13 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 325 PM EST FRI DEC 13 2013
WIDESPREAD SNOW WILL DEVELOP TONIGHT AND CONTINUE ALL DAY SATURDAY
AS A LOW PRESSURE SYSTEM MOVES THROUGH THE OHIO VALLEY. MORE LAKE
EFFECT SNOW SHOWERS ARE LIKELY ON SUNDAY BEHIND THIS SYSTEM.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 325 PM EST FRI DEC 13 2013
LITTLE CHANGE TO THE GOING FORECAST AS LATEST MODEL GUIDANCE REMAINS
VERY CONSISTENT IN SHOWING A PROLONGED 24 HOUR SNOW EVENT WITH
WIDESPREAD 3 TO 5 INCH ACCUMULATIONS. THE LOWER END AMOUNTS ARE
EXPECTED TO BE AROUND LUDINGTON AND PENTWATER WHILE THE HIGHER
AMOUNTS SHOULD BE AROUND LAN AND JXN.
HOWEVER FGEN FORCING THROUGH THIS EVENT COULD LEAD TO NON
UNIFORM/VARIABLE STORM TOTAL ACCUMULATIONS ACROSS THE CWFA...WITH
LOCALLY HIGHER AMOUNTS WHERE NARROW FGEN BANDS SET UP AND PERSIST.
THE ADVISORY REMAINS UNCHANGED WITH THE 9 PM START TIME ALTHOUGH IT
COULD TAKE UNTIL WELL AFTER MIDNIGHT BEFORE THE SNOW BECOMES MORE
WIDESPREAD AND IS IMPACTING THE ENTIRE CWFA. THE BULK OF THE STORM
TOTAL SNOW WILL FALL ON SATURDAY. THIS EVENT FEATURES A DEEP BUT
HIGH DGZ CENTERED BETWEEN 7K AND 15K FEET WITH GENERALLY WEAK BUT
DEEP OMEGAS. SNOW RATIOS ARE EXPECTED TO BE ABOUT 15:1 AND THE SNOW
SHOULD HAVE A WETTER CONSISTENCY THAN RECENT EVENTS.
LATEST SHORT TERM HI RES MODEL GUIDANCE CONTINUES TO INDICATE A
STRONG POTENTIAL OF A NARROW WEST TO EAST ORIENTED BAND OF FGEN SNOW
DEVELOPING IN SRN LWR MI THIS EVENING WELL AHEAD OF THE MAIN SYSTEM
SNOW WHICH DOES NOT REALLY ARRIVE UNTIL WELL AFTER MIDNIGHT.
THIS FGEN BAND DEVELOPS NEAR OR JUST SOUTH OF THE I-96 CORRIDOR
BETWEEN 00Z AND 03Z AND CONTINUES THROUGH 06Z-09Z BEFORE BEING
ABSORBED IN WITH THE MORE BROAD/WIDESPREAD SYSTEM SNOW LATE TONIGHT.
BEST ATTEMPT AT PINPOINTING THE EXACT AREA IS A HOLLAND TO HASTINGS
TO CHARLOTTE TO MASON LINE... GIVE OR TAKE 25 MILES.
ANOTHER MESOSCALE ISSUE THAT MAY COME INTO PLAY EVENTUALLY IS EAST
FLOW LAKE ENHANCEMENT OFF LAKE HURON WHICH COULD LEAD TO LOCALLY
HIGHER AMOUNTS IN THE CLARE COUNTY AREA.
THE LAKE EFFECT SNOW EVENT FOR SUNDAY APPEARS TO HAVE RELATIVELY
SHALLOW MOISTURE WITH INVERSION HEIGHTS AROUND 5K FEET. HOWEVER THE
DGZ IS 3-5K FT DEEP AND IN THE CLOUD LAYER SO SOME DECENT SNOW
SHOWERS CAN STILL BE EXPECTED. LOW LEVEL FLOW WILL BE WEST NORTHWEST
AND 15 TO 25 KTS... SO THE SNOW SHOWERS SHOULD CARRY WELL INLAND.
ADDITIONAL ACCUMULATIONS OF 1 TO 4 INCHES ARE LIKELY ALONG AND WEST
OF HWY 131.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 325 PM EST FRI DEC 13 2013
THE BELOW AVERAGE TEMPERATURES AND UNSETTLED WEATHER PATTERN/LAKE
EFFECT WILL CONTINUE TO AFFECT THE STATE INTO MID WEEK NEXT WEEK.
CONFIDENCE IS GROWING THAT WE SHOULD SEE AT LEAST A SHORT BREAK IN
THE COLD AIR.
MAX TEMPS IN THE 20S AND OCCASIONAL CHCS OF SNOW SHOWERS WILL EXIST
FROM THE BEGINNING OF THE LONG TERM THROUGH WED. WE WILL REMAIN
GENERALLY IN THE LONGER WAVE TROUGH WITH NW FLOW DURING THIS PERIOD.
THIS WILL BRING HARD TO TIME SHORT WAVES THROUGH THE AREA. ONSHORE
LOW LEVEL FLOW AND COLD AIR WILL KEEP LAKE EFFECT THREAT AROUND...
THAT WOULD BE ENHANCED BY ANY SHORT WAVES THAT DO COME THROUGH. THE
DETAILS WILL HAVE TO BE IRONED OUT AS WE GET CLOSER TO THAT PERIOD.
WE CONTINUE TO EXPECT A MODERATION IN TEMPS OF SOME DEGREE THEN FOR
THE END OF NEXT WEEK. THE MODERATION IN TEMPS WILL LIKELY BE
ACCOMPANIED BY MORE UNSETTLED WEATHER...WITH POSSIBLE RAIN AND/OR
SNOW. THE UPPER TROUGH OVER THIS REGION OF THE COUNTRY IS STILL
EXPECTED TO BE PUSHED OUT BY A STRONG UPPER JET DIVING IN FROM THE
SRN ALASKA COAST. WE WILL SEE THE FLOW TRANSITION FROM THE NW FLOW
EARLY IN THE WEEK TO SW FLOW LATE IN THE WEEK AFTER THE TROUGH IS
DUG ACROSS THE DESERT SW.
THE FIRST SYSTEM TO COME FROM THE WRN TROUGH WILL AFFECT THE AREA
LATE THU INTO FRI. DEPENDING ON HOW STRONG THIS ENDS UP...WILL BE
HOW WARM WE GET AND HOW MUCH OF A PCPN TRANSITION WE SEE. WE DO
EXPECT AT THIS TIME FOR RAIN TO BE A LIKELY P-TYPE WITH A GOOD CHC
OF TEMPS IN THE 40S. WE HAVE GONE WITH A MIX FOR NOW WITH
UNCERTAINTY STILL PRESENT. WE COULD SEE SOME POSSIBLE HYDRO ISSUES
WITH ICE JAMS AND/OR HIGH FLOWS IF ENOUGH WARM AIR AND RAIN COMES
IN. MUCH COLDER AIR WILL MOVE BACK IN BEYOND THE LONG TERM.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 626 PM EST FRI DEC 13 2013
THERE IS LITTLE QUESTION LIFT CONDTIONS WILL PREVAIL AT MOST IF
NOT ALL OF THE TAF SITES BY 12Z SATURDAY. THE QUESTION IS MORE
WHEN DOES THE SNOW MOVE IN.
CURRENTLY THE LOW CLOUDS HAVE CLEARED OUT OF ALL OF THE TAF SITES
AND I AM THINKING THEY WILL NOT RETURN UNTIL THE SNOW GETS
UNDERWAY. LOOKING AT RAP MODEL SOUNDING IT IS NOT UNTIL BTWN 06Z
AND 09Z THE SOUNDINGS GET MOIST ENOUGH FOR SNOW TO REACH THE
GROUND. ONCE THAT DOES HAPPEN THOUGH THERE WILL BE A FAIRLY LONG
PERIOD OF LIGHT TO MODERATE SNOW ACROSS THE AREA THAT WILL RESULT
IN SOLID LIFR CONDTIONS FROM SAY 09Z THROUGH 23Z TO 24Z.
THERE IS THE SUGGESTIONS IN THE MODELS THAT A BAND OF SNOW MAY
FORM BETWEEN I-94 AND I-96 BY 03Z. MY PROBLEM WITH PUTTING THAT
IN OUR TAFS IS THE AIR IS DRY FOR NEARLY 10000 FT BELOW THE CLOUD
BASE THAT WOULD BE PRODUCING THE SNOW. I HAVE TO WONDER HOW MUCH
OF THE SNOW WILL MAKE IT TO THE GROUND. SINCE AT 23Z NONE OF THE
OBSEVATIONS UNDER THE BAND OVER SOUTHERN WISCONSIN ARE MAKING IT
TO THE GROUND YET... I WAS CONSERVATIVE WITH THE START TIME OF THE
SNOW AND LARGELY USED THE RAP MODEL SHOWING NEAR SATURATED
SOUNDING TO PUT MY START TIMES IN THE TAFS.
&&
.MARINE...
ISSUED AT 325 PM EST FRI DEC 13 2013
EAST WINDS WILL INCREASE TONIGHT BUT WAVES WILL BE LOW DUE TO
OFFSHORE FLOW. NEXT ACTIVE PERIOD WILL BE LATE SATURDAY NIGHT AND
&&
.HYDROLOGY...
ISSUED AT 325 PM EST FRI DEC 13 2013
MOST OF THE RIVERS HAVE COMPLETELY ICED OVER WHICH MEANS THE ICE JAM
THREAT HAS DECREASED. IT STILL NEEDS TO BE WATCHED... ESPECIALLY
LATE NEXT WEEK WHEN A POTENTIAL WARM UP COULD BREAK UP THE ICE AND
CREATE MOVEMENT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 10 PM EST SATURDAY FOR MIZ037>040-
043>046-050>052-056>059-064>067-071>074.
LM...NONE.
&&
$$
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...NJJ
AVIATION...WDM
HYDROLOGY...MEADE
MARINE...MEADE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
421 PM EST THU DEC 12 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 419 PM EST THU DEC 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
ACROSS ERN NOAM RESULTING IN NW FLOW THROUGH THE NRN GREAT LAKES. A
SHORTWAVE TROUGH WAS MOVING THROUGH NW ONTARIO DRAGGING A COLD FRONT
THROUGH WRN LAKE SUPERIOR. FARTHER UPSTREAM...A WEAK CLIPPER SHRTWV
WAS MOVING FROM SRN SASK INTO THE NRN PLAINS. LES BANDS ALIGNED WITH
WNW FLOW THROUGH ERN LAKE SUPERIOR INTO NE ALGER AND NRN LUCE
COUNTIES HAD DIMINISHED SLIGHTLY AND BECOME MORE CELLULAR THIS
AFTERNOON WITH WEAKENING LOW LEVEL CONV FROM LAND BREEZE COMPONENT.
EXPECT THAT THE LOW LEVEL WINDS WILL DIMINISH AND VEER FROM WNW TO
NRLY. THIS SHOULD PUSH THE MORE SIGNIFICANT LES THROUGH MUCH OF THE
ERN CWA FROM ALGER COUNTY EASTWARD AS A STRENGTHENING LAND BREEZE
SHOULD KEEP MOST OF THE SNOW EAST OF MARQUETTE. EVEN WITH THE
SHIFTING POSITION OF THE LES BANDS...FAVORABLE SNOW GROWTH WITH THE
DGZ IN THE 1K-4K CONVECTIVE LAYER PUSHING SLR VALUES ABOVE 25/1 AND
SHOULD SUPPORT ADVISORY SNOWFALL AMOUNTS IN THE 3 TO 6 INCH RANGE.
OVER THE WEST...THE SHORTER FETCH...ACYC FLOW AND LOWER INVERSION
HEIGHTS FROM 3K-4K FT...WILL KEEP SNOWFALL AMOUNTS IN THE 1 TO 3
INCH RANGE.
FROM LATE TONIGHT INTO EARLY FRI...THE SASK SHRTWV AND WEAK UPPER
LEVEL DIV WITH THE RIGHT ENTRANCE OF A 140 KT 250-300 MB JET WITH
ASSOCIATED 800-600 MB FGEN MAY SUPPORT A BAND OF LIGHT SNOW.
HOWEVER...MODELS SUGGEST THAT THE BEST CHANCE OF LIGHT SNOW WITH
THESE FEATURES WILL REMAIN OVER WI. SO...ONLY CHANCE POPS WITH
ACCUMULATIONS LESS THAN A HALF INCH WERE INCLUDED.
WINDS WILL CONTINUE TO VEER FRIDAY AS ARCTIC HIGH PRES FROM
SASK/MANITOBA INTO NRN ONTARIO BUILDS INTO THE NRN LAKES. WITH WINDS
SHIFTING FROM N TO NNE THE MOST FAVORABLE LOW LEVEL CONV WILL SHIFT
FROM THE NE CWA INTO MARQUETTE COUNTY. WHILE SNOW GROWTH WILL REMAIN
FAVORABLE...INVERSION HEIGHT REMAINING NEAR 5K-6K FT WITH MAINLY
ACYC UPSTREAM FLOW MAY LIMIT LES INTENSITY AND SNOWFALL AMOUNTS
BELOW ADVY LEVELS. GENERALLY 1 TO 3 INCHES ARE EXPECTED WITH THE
GREATEST AMOUNTS IN FAR WRN ALGER COUNTY INTO ERN MARQUETTE COUNTY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 419 PM EST THU DEC 12 2013
MODELS TODAY CONTINUE TO INDICATE AN OVERALL COLD PATTERN THRU THE
LONG TERM PORTION OF THE FCST. HOWEVER...WITH CURRENT DEEP EXPANSIVE
POLAR VORTEX CENTERED AROUND HUDSON BAY STILL FCST TO WEAKEN AND
RETREAT N THRU AT LEAST THE MIDDLE OF NEXT WEEK...THE COLD WILL EASE
SOME. A VAST SUPPLY OF COLD AIR WILL REMAIN ACROSS CANADA...SO ANY
SHORTWAVE TRACKING ALONG IN THE RELAXING NW FLOW PATTERN WILL BE
ABLE TO TUG COLDER AIR INTO THE UPPER LAKES. FOR THIS REASON...
MEDIUM RANGE GUIDANCE FOR SEVERAL DAYS HAS BEEN PROGRESSIVELY SLOWER
TO BRING WARMING INTO THE UPPER LAKES AND HAS ALSO BEEN MORE
TEMPERED WITH THE WARMING. AROUND THE MIDDLE OF NEXT WEEK THERE WILL
BE A TEMPORARY SHIFT IN THE PATTERN TOWARD A DEEPENING TROF OVER THE
WRN CONUS AND DOWNSTREAM BUILDING RIDGE OVER THE SE CONUS/WRN
ATLANTIC. THUS THE MIDWEEK PERIOD WILL OFFER THE BEST CHANCE OF A
WARMUP. HOW MUCH WARMING OCCURS WILL DEPEND ON THE AMPLITUDE AND
LONGITUDE OF THE TROF/RIDGE PATTERN. LATEST MODEL TRENDS POINT
TOWARD AN EWD SHIFT IN THE TROF/RIDGE PATTERN WHICH WILL LIMIT
WARMING FOR THE UPPER LAKES. IN ANY CASE...WARMING WILL ONLY BE
BRIEF AS LONGER RANGE GUIDANCE CONTINUES TO POINT TOWARD
REINTENSIFYING ARCTIC AIR ACROSS WRN/NRN CANADA DUMPING BACK INTO
THE AREA SOMETIME AROUND THE WEEKEND BEFORE CHRISTMAS. OUTSIDE OF
AREAS AFFECTED BY LES/LAKE ENHANCEMENT...THERE WON`T BE MUCH MORE
THAN SOME -SN AT TIMES DURING THE LONG TERM. THE RESURGENCE OF
ARCTIC AIR S INTO THE CONUS LATE NEXT WEEK/WEEKEND COULD OFFER THE
POTENTIAL FOR SOMETHING MORE SUBSTANTIAL IN TERMS OF WIDESPREAD
SNOWFALL.
BEGINNING FRI NIGHT...WINDS WILL CONTINUE VEERING TO THE E THEN
SE FRI NIGHT/SAT MORNING AS SFC HIGH PRES CENTER PASSES JUST N OF
LAKE SUPERIOR AND NEXT CLIPPER SHORTWAVE APPROACHES FROM THE NW. LES
THAT WILL BE OCCURRING MAINLY INTO NCNTRL UPPER MI THU AFTN WILL
SLOWLY SHIFT OUT OF NCNTRL UPPER MI AND THEN CROSS THE KEWEENAW
PENINSULA FOR A TIME LATE FRI NIGHT/SAT MORNING. DGZ WILL BE WELL
CENTERED IN THE CONVECTIVE LAYER...SO A FEW INCHES OF FLUFFY SNOW
ARE POSSIBLE IN THIS AREA OF LES THAT WILL BE SHIFTING WITH THE
WINDS. ALSO...WITH WINDS VEERING OVER NRN LAKE MI...LES OFF LAKE MI
WILL LIKELY MOVE INTO MENOMINEE COUNTY AND POSSIBLY DELTA COUNTY...
LEADING TO SOME FLUFFY SNOW ACCUMULATIONS LATE FRI NIGHT/SAT
MORNING.
ATTENTION THEN TURNS TO NEXT CLIPPER SHORTWAVE DROPPING THRU THE
UPPER GREAT LAKES SAT NIGHT/SUN. -SN ASSOCIATED WITH FEATURE SHOULD
SPREAD INTO THE AREA SAT AFTN/EVENING...AND IT LOOKS LIKE THERE WILL
BE A PERIOD OF LAKE ENHANCEMENT OFF LAKE MI IN SOUTHERLY FLOW...
LEADING TO A POTENTIAL ADVY EVENT. A BRIEF SHOT OF ARCTIC AIR
FOLLOWING SYSTEM WILL PROBABLY RESULT IN A SHORT DURATION PERIOD OF
MDT TO POSSIBLY HVY LAKE ENHANCED SNOW FOR NORTHWEST AND NORTHEAST
UPPER MI LATE SAT NIGHT/EARLY SUNDAY AS WIND SHIFTS NW. SINCE DEEP
LAYER FORCING WITH SHORTWAVE IS FAIRLY IMPRESSIVE...WILL NEED TO
WATCH FOR LOCALLY HVY LAKE ENHANCED SNOW OFF LAKE MI AHEAD OF WAVE
AND OFF LAKE SUPERIOR AS THE WAVE PASSES. AS WINDS VEER AROUND TO
THE N OR NE WITH SFC HIGH PRES PASSING ACROSS NRN ONTARIO...LIGHTER
LES WILL AGAIN SHIFT TO AFFECT MORE OF NRN UPPER MI SUN
AFTN/EVENING.
OVER THE LAST FEW DAYS...UNCERTAINTY FOR THE EARLY AND MIDDLE PARTS
OF NEXT WEEK HAS BEEN HIGH WITH REGARD TO TIMING/STRENGTH/TRACK OF
SEVERAL SHORTWAVES IN WNW FLOW. IT APPEARS THERE MAY BE A COUPLE OF
PERIODS OF WIDESPREAD -SN (CONFIDENCE HIGHEST FOR -SN ON MON) AS
WELL AS LAKE ENHANCEMENT OFF LAKE MICHIGAN AND LAKE SUPERIOR
DEPENDING ON WIND DIRECTION IMMEDIATELY PRIOR TO AND AFTER PASSAGE
OF THE WAVES. GIVEN THE SPREAD OF SOLUTIONS IN RECENT DAYS...
CONFIDENCE IN SNOW AND TEMP FCSTS FOR MON-WED ESPECIALLY TUE/WED
WILL BE LOW UNTIL THAT PART OF THE FCST MOVES CLOSER TO THE SHORT
TERM.
THERE ARE SOME INDICATIONS THAT A SOMEWHAT MORE MEANINGFUL LOW PRES
WAVE MAY MOVE TOWARD THE GREAT LAKES THU/FRI AS THE WRN TROF
DEVELOPS/DEEPENS AND BEGINS TO SHIFT E.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 108 PM EST THU DEC 12 2013
CMX...WNW LOW LEVEL FLOW WILL CONTINUE TO BRING LIGHT TO PRODUCE
OCCASIONALLY MODERATE LAKE EFFECT SNOW SHOWERS THROUGH THIS
AFTERNOON. AS THE WINDS VEER NRLY TONIGHT...THE LES IS EXPECTED TO
DIMINISH.
IWD...AS WINDS VEER TO THE NW AND N TONIGHT...LIGHT TO MODERATE LAKE
EFFECT SNOW SHOWERS WILL MOVE IN...BRINGING MAINLY IFR VSBY AND MVFR
CIGS.
KSAW...EXPECT VFR CONDITIONS THROUGH TODAY BEFORE A TROUGH PASSAGE
FROM THE NORTH BRINGS SOME LIGHT LAKE EFFECT SNOW ACROSS THE
TERMINAL. THE BEST CHANCE FOR OCCASIONAL SNOW SHOWERS WITH
MVFR CONDITIONS WILL BE LATE TONIGHT AND FRIDAY MORNING AFTER WINDS
BECOME MORE NORTHWESTERLY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EST THU DEC 12 2013
A PERIOD OF WNW TO NW GALES IS EXPECTED LATE THIS AFTERNOON THROUGH
THIS EVENING BEFORE DIMINISHING OVERNIGHT WITH HIGH PRES BUILDING
TOWARD THE REGION. HEAVY FREEZING SPRAY WILL ALSO CONTINUE FOR MUCH
OF THE LAKE INTO THIS EVENING. WINDS WILL FINALLY DIMINISH TO
NORTHERLY AT 15 TO 25 KNOTS OVERNIGHT INTO FRIDAY MORNING AS A WEAK
RIDGE PASSES ACROSS THE LAKE. EXPECT 10 TO 20 KT WINDS TO GRADUALLY
BACK TO THE SE BY SATURDAY AHEAD OF DEVELOPING LOW PRESSURE OVER THE
UPPER MS VALLEY. DEPENDING ON THE STRENGTH OF THE LOW AS IT MOVES
ACROSS LAKE SUPERIOR ON SATURDAY NIGHT AND SUNDAY AND THE STRENGTH OF
ANOTHER LOW MOVING UP THE EAST COAST...COULD SEE AN INCREASE IN
NORTHWESTERLY WINDS ON SUNDAY TO 25 TO 30 KTS. THIS WILL BE SHORT-
LIVED AS ANOTHER HIGH SLIDES INTO THE AREA FOR THE BEGINNING OF THE
UPCOMING WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 6 AM EST FRIDAY FOR MIZ006-007-
085.
LAKE SUPERIOR...
GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ266-267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST FRIDAY FOR
LSZ263>266.
GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LSZ264-265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...ROLFSON
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1230 AM EST THU DEC 12 2013
.UPDATE...
ISSUED AT 845 PM EST WED DEC 11 2013
LATEST MQT RADAR SHOWS LES BANDS OVER ERN LK SUP HAVE SHIFTED TO THE
N OF GRAND MARAIS. WITH THE LLVL FLOW EXPECTED TO BACK TO MORE WSW
THRU THE NGT...EXPECT THESE BANDS TO STAY N OF ALGER COUNTY. SO CANX
GOING ADVY FOR THAT COUNTY EARLY. THE HEAVIER BANDS ARE STILL
IMPACTING FAR NRN LUCE COUNTY...SO WL KEEP THE WRNG GOING FOR THAT
AREA FOR NOW EVEN THOUGH WIND TRENDS MAY SHIFT THE BANDS N OF THE
COUNTY BEFORE 12Z. MAY CANX THE HEADLINE FOR THIS COUNTY AS WELL IF
PRESENT TRENDS CONTINUE. STLT IMAGERY ALSO SUGS THE BANDS HAVE
SHIFTED OUT OF ALL BUT FAR NRN ONTONAGON COUNTY. CALL TO A SPOTTER
JUST N OF ONTONAGON INDICATES ONLY LGT SN IS FALLING THERE...WITH
JUST AN INCH OF ACCUMULATION THRU THE DAY AND INTO THE EVNG.
CONSIDERING THE SAME BACKING FLOW THAT SHOULD CAUSE THE LES TO IMPACT
AREAS MAINLY N OF ONTONAGON COUNTY...OPTED TO CANX THE LES ADVY FOR
THAT COUNTY AS WELL.
PRES FALL CENTER ASSOCIATED WITH SHRTWV DIGGING SEWD INTO THE UPR
MIDWEST WL PASS TO THE SW OF UPR MI TNGT...SO EXPECT WINDS WL BE
LIGHTER THAN ORIGINALLY FCST. HI CLDS ASSOCIATED WITH THIS
DISTURBANCE WL PASS OVER AT LEAST THE SW HALF OF THE CWA AND
PROBABLY LIMIT THE DIURNAL TEMP FALL AS WELL SO WIND CHILLS WL
PROBABLY END OF NOT BEING AS HARSH AND MORE MARGINAL FOR ADVY...ARND
-25F INSTEAD OF -30 TO -35. OPTED TO KEEP THE GOING WIND CHILL
HEADLINES DESPITE THE MORE MARGINAL NATURE OF THE STILL HAZARDOUS
COLD.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 407 PM EST WED DEC 11 2013
TWO MAIN ITEMS OF FOCUS IN THE SHORT TERM PERIOD...THE ONGOING LAKE
EFFECT SNOW AND THE CONTINUED COLD WEATHER.
LARGE NORTHERN STREAM UPPER TROUGH COVERS THE UPPER GREAT LAKES
REGION AT THIS TIME...ALLOWING RAP ANALYZED 850MB TEMPS TO BE
AROUND -24C. AT THE SURFACE...A LAKE INDUCED TROUGH REMAINS OVER
THE FAR EASTERN LAKE...WHILE HIGH PRESSURE CENTERED OVER NORTHERN
MISSOURI IS PUSHING A RIDGE OVER NORTHERN MINNESOTA AND NORTHWEST
WISCONSIN. THE COLD AIR MOVING OVER THE RELATIVELY WARM LAKE
SUPERIOR WATERS CONTINUES TO PRODUCE LAKE EFFECT IN THE WEST TO
NORTHWEST WIND LOCATIONS THIS AFTERNOON. THE 925/850MB TROUGH THAT
WAS OVER THE AREA THIS MORNING HAS ALREADY SHIFTED EAST OF THE CWA
AND STARTED TO BACK THE WINDS IN THE LOWER LEVELS OVER THE WESTERN
CWA. THIS CAN BE SEEN IN THE VISIBLE SATELLITE IMAGERY OVER THE
WEST...AS THE BANDS HAVE STARTED TO BECOME WEST-EAST ORIENTATED.
THESE BACKING WINDS ARE ALSO STARTING TO REACH THE CENTRAL LAKE
WHERE THE BANDS ARE NOW MORE IN A WNW DIRECTION AND WINDS AT
STANNARD ROCK HAVE SHIFTED TO THE WEST. EASTERN ALGER AND NORTHERN
LUCE HAVE SEEN THE MOST SNOW TODAY...WITH REPORTS IN THE 2-8 INCH
RANGE.
THE HIGH PRESSURE RIDGE THAT HAS STARTED TO MOVE INTO THE WESTERN
CWA WILL CONTINUE EAST TONIGHT...WHICH WILL CONTINUE TO BACK WINDS
THIS EVENING...TO MORE OF A WESTERLY DIRECTION OR EVEN
WEST-SOUTHWEST OVER THE WESTERN CWA. THESE BACKING WINDS WILL
LIKELY LEAD TO A MORE DOMINATE BAND SETTING UP OVER THE
WEST (WITH THE HELP OF COASTAL CONVERGENCE)...LIKELY IN A SIMILAR
LOCATION TO WHAT WAS SEEN ON MONDAY. UNLIKE MONDAY...INVERSION
HEIGHTS WILL BE FALLING AND MUCH LOWER DUE TO THE APPROACHING
HIGH PRESSURE RIDGE AND INCREASED SUBSIDENCE. THIS COMPRESSES THE
MOISTURE TO AROUND 5KFT FOR CLOUD TOPS...EVEN THOUGH LAKE INDUCED
EQUILIBRIUM LEVELS REACH 8-9KFT. WHILE THIS OCCURS...IT DOES TRY TO
PUSH THE BETTER LAKE FORCING INTO THE TOP OF THE DGZ...WHICH MAY AID
SNOWFALL SIZE/RATIOS TO BE A LITTLE HIGHER THAN SEEN OVER THE LAST
DAY. WITH THE AIDED CONVERGENCE DUE TO WINDS BACKING TO THE
SOUTHWEST...WOULD THINK THAT WOULD HELP OFFSET SOME OF THE LARGE
SCALE SUBSIDENCE AND LEAD TO DECENT ACCUMULATING SNOWFALL FOR
NORTHERN HOUGHTON COUNTY AND THE SOUTHERN PART OF KEWEENAW COUNTY
TONIGHT. THERE IS SOME QUESTION ON HOW QUICKLY IT WILL MOVE NORTH
AND WHERE/WHEN IT WILL STALL TONIGHT. LOCAL HIRES WRF-ARW RUNS
(WHICH HAVE PERFORMED WELL WITH LOCATIONS OVER THE LAST 24HRS) ARE
DIFFERING ON HOW FAR NORTH IT WILL GO...ALONG WITH THE 12Z NAM...SO
OPTED TO SHOW IT REACHING STOPPING AROUND THE HOUGHTON-MOHAWK AREA.
THEREFORE...DID EXPAND SNOWFALL AMOUNTS FARTHER NORTH AND ALSO THE
LES ADVISORY. WAS TEMPTED TO BUMP UP TO A WARNING SINCE THERE WERE
REPORTS OUT WEST WITH 1 IN/HR SNOWFALL IN THE COLDER AIR AND LESS
DGZ INFLUENCE...BUT WITH INVERSION HEIGHTS BEING LOWER DECIDED TO
KEEP AMOUNTS AT HIGH END ADVISORY. WILL NEED TO KEEP AN EYE ON
THINGS THIS EVENING...AS THERE IS THE POTENTIAL FOR BORDERLINE
WARNING AMOUNTS WHERE THAT BAND SETS UP. HEADING INTO
THURSDAY...SLIGHTLY WARMER 925-850MB TEMPS DOES PUSH MORE OF THE
CLOUD INTO THE DGZ...WHICH COULD AID SNOWFALL RATIOS EVEN WITH THE
CONTINUED LIMITED CLOUD DEPTH (INVERSION STAYS THE SAME). WINDS LOOK
TO VEER TO MORE OF A WEST-NORTHWEST AS THE TROUGH SLIDES SOUTH
AGAIN...SO WOULD EXPECT LESS CONVERGENCE AFFECTING THE KEWEENAW
PENINSULA AND THE STRONG CONVERGENCE BAND TO SHIFT BACK TO THE
SOUTH. AS FOR THE OTHER ADVISORIES...ENDED GOGEBIC/BARAGA AND SRN
HOUGHTON EARLY AND ALSO TRENDED ONTONAGON TO AN EARLIER END TIME
DUE THE STRONGEST BAND JUST BRUSHING THE FAR NORTHERN PART OF THAT
COUNTY.
OVER THE EAST...THE BACKING WINDS HAVE ALREADY STARTED TO PUSH
THE STRONGER BANDS NORTHEAST AND WOULD EXPECT THAT STEADY PUSH
TO CONTINUE THIS EVENING. THIS STEADY PUSH SHOULD LEAD TO MORE
STEADY/WIDESPREAD ACCUMULATIONS...GENERALLY IN THE 2-5IN RANGE.
TIMING OF THE ADVISORY FOR ALGER AND NRN SCHOOLCRAFT LOOKS GOOD AND
MAY BE ABLE TO END THE LUCE WARNING A COUPLE HOURS EARLY OVERNIGHT.
AFTER THESE BANDS PUSH NORTHEAST...WOULD EXPECT SKIES TO CLEAR OUT.
THE WESTERLY (OR EVEN SLIGHTLY WSW) FLOW WILL CONTINUE INTO TOMORROW
MORNING...BEFORE THE TROUGH DROPS TO THE SOUTH AND WINDS SHIFT BACK
TO THE WEST-NORTHWEST. THIS SHOULD BE ENOUGH TO MOVE THE BANDS BACK
ONSHORE. INVERSION HEIGHTS WILL BE A LOT LOWER THAN SEEN TODAY
(RADAR INDICATED OF 10-11KFT THIS AFTN DECREASING TO 6-7KFT LATE
TONIGHT THROUGH TOMORROW AFTERNOON). EVEN SO...ENHANCED CONVERGENCE
ALONG THE NEXT TROUGH COULD BE ENOUGH TO LEAD TO A QUICK COUPLE OF
INCHES THURSDAY AFTERNOON OVER LUCE COUNTY.
AS FOR THE COLD TEMPERATURES...ONLY MADE MINOR TWEAKS TO LOWS
TONIGHT AND WINDS. LOWS ARE A LITTLE TRICKY WITH THE HIGH
PRESSURE RIDGE TRYING TO SLIDE IN AND THE MODELS SHOWING
WINDS STRUGGLING TO DECOUPLE. BASED OFF INTERIOR LOCATIONS
LAST NIGHT FALLING TO 4-7KTS...THINK THAT SEEMS REASONABLE FOR
TONIGHT AND POTENTIALLY A LITTLE LOWER WITH THE HELP OF THE HIGH
PRESSURE RIDGE MOVING IN. EXPECT MOST LOCATIONS TO BE WELL BELOW
ZERO WITH THE COLDEST VALUES CONTINUING OVER THE INTERIOR WEST AND
CENTRAL (LOWS IN THE TEENS BELOW ZERO). WIND CHILL ADVISORY LOOKS
TO BE IN GOOD SHAPE AFTER THE MINOR ADJUSTMENTS AND WILL LEAVE THAT
AS IS. ONE OTHER ITEM TO NOTE IS A WEAK SHORTWAVE DIVING SOUTHEAST
ON THE BACK SIDE OF THE UPPER TROUGH THAT WILL MOVE THROUGH
NORTHERN MINNESOTA THIS EVENING AND INTO WISCONSIN OVERNIGHT. MAIN
INFLUENCE WILL BE SOME MID-HIGH CLOUDS...BUT INDICATIONS ARE THAT
MOST OF THOSE CLOUDS WILL STAY SOUTHWEST OF THE CWA TONIGHT BUT MAY
STREAM OVER DURING THE DAY TOMORROW. AREAS RIGHT ALONG THE WISCONSIN
BORDER WOULD HAVE THE BEST OPPORTUNITY FOR THESE MID CLOUDS...WHICH
COULD LEAD TO TEMPS WARMING SLIGHTLY TOWARDS DAYBREAK.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 430 PM EST WED DEC 11 2013
MODELS CONTINUE TO SUGGEST AN OVERALL COLD PATTERN THRU THE LONG
TERM PORTION OF THE FCST. HOWEVER...WITH CURRENT DEEP EXPANSIVE
POLAR VORTEX CENTERED AROUND HUDSON BAY WEAKENING AND RETREATING N
LATE THIS WEEK THRU AT LEAST THE MIDDLE OF NEXT WEEK...THE COLD WILL
EASE SOME. A VAST SUPPLY OF COLD AIR WILL REMAIN ACROSS CANADA...SO
ANY SHORTWAVE TRACKING ALONG IN THE RELAXING NW FLOW PATTERN WILL BE
ABLE TO BRING A SURGE OF COLDER AIR INTO THE UPPER LAKES. OVER THE
PAST SEVERAL DAYS...MEDIUM RANGE GUIDANCE HAS BEEN PROGRESSIVELY
SLOWER TO BRING WARMING INTO THE UPPER LAKES FOR THIS REASON. LATER
DOWN THE ROAD NEXT WEEK...THERE ARE SUGGESTIONS OF A TEMPORARY SHIFT
IN THE PATTERN TOWARD A DEEPENING TROF OVER THE WRN CONUS AND
DOWNSTREAM BUILDING RIDGE OVER THE SE CONUS/WRN ATLANTIC. THIS WILL
OFFER THE BEST CHANCE OF A WARMUP THAT WOULD OCCUR AROUND THE MIDDLE
NEXT WEEK. HOW MUCH WARMING OCCURS WILL DEPEND ON THE AMPLITUDE AND
LONGITUDE OF THE TROF/RIDGE PATTERN. WHATEVER HAPPENS...ANY WARMING
WILL ONLY BE BRIEF AS LONGER RANGE GUIDANCE POINTS TOWARD
REINTENSIFYING ARCTIC AIR ACROSS WRN/NRN CANADA DUMPING BACK INTO
THE AREA SOMETIME AROUND THE WEEKEND BEFORE CHRISTMAS OR EARLY
CHRISTMAS WEEK. OUTSIDE OF THE AREAS AFFECTED BY LES...DON`T EXPECT
MUCH MORE THAN SOME -SN AT TIMES DURING THE LONG TERM. POSSIBLE
BRIEF PATTERN CHANGE LATER NEXT WEEK COULD OFFER THE POTENTIAL FOR
SOMETHING MORE SUBSTANTIAL IN TERMS OF PCPN.
BEGINNING THU NIGHT...SHORTWAVE PASSING ACROSS NRN ONTARIO WILL SEND
A SFC TROF S THRU THE UPPER LAKES...CAUSING WINDS TO VEER NW OR N BY
FRI MORNING. AS A RESULT...ONGOING WRLY FLOW LES LATE THU AFTN WILL
SPREAD S...AFFECTING MOST IF NOT ALL OF NRN UPPER MI BY FRI MORNING.
ALTHOUGH THERE IS NOT MUCH IN THE WAY OF DEEP LAYER FORCING...PERIOD
OF DEEPER MOISTURE COMBINED WITH CONVERGENCE ALONG TROF SHOULD YIELD
A SHORT PERIOD OF MDT SNOW AND POSSIBLY BRIEF HVY SNOW AS TROF
SWEEPS S THU NIGHT AND FRI MORNING. BEHIND TROF...INVERSION SETTLES
TO AROUND 5-6KFT FRI. LARGER SCALE LOW-LEVEL FLOW ALSO BECOMES MORE
ANTICYCLONIC FRI. ON THE OTHER HAND...DIMINISHING BOUNDARY LAYER
WINDS MAY ALLOW FOR LOCALIZED CONVERGENCE. IN FACT...NAM INDICATES
WINDS VEERING TO ESE OFF ERN UPPER MI DURING THE DAY FRI...
RESULTING IN A ZONE OF ENHANCED CONVERGENCE EXTENDING ACROSS FAR SE
LAKE SUPERIOR TO THE MARQUETTE AREA. WILL BE SOMETHING TO MONITOR.
OTHERWISE...DGZ WILL BEGIN TO BECOME BETTER LOCATED WITHIN THE
CONVECTIVE LAYER AND UPWARD MOTION ZONE...LEADING TO HIGHER SNOW TO
WATER RATIOS. SO...SHOULD BE ABLE TO FLUFF UP SOME DECENT SNOW
ACCUMULATIONS FRI WHERE LES IS MOST PERISTENT (NCNTRL UPPER MI). OUT
W DURING THE DAY...WINDS MAY END UP VEERING ENOUGH TO PUSH MOST OF
THE LES OFFSHORE OF WRN UPPER MI...EXCEPT FOR THE KEWEENAW.
WINDS CONTINUE VEERING TO THE E THEN SE FRI NIGHT/SAT MORNING AS SFC
HIGH PRES CENTER PASSES JUST N OF LAKE SUPERIOR. LES THAT WILL BE
OCCURRING MAINLY INTO NCNTRL UPPER MI THU AFTN WILL THEN SLOWLY
SHIFT...CROSSING THE KEWEENAW PENINSULA FOR A TIME LATER FRI
NIGHT/SAT MORNING. DGZ WILL STILL BE WELL CENTERED IN THE CONVECTIVE
LAYER...SO A FEW INCHES OF FLUFFY SNOW ARE POSSIBLE. IF WINDS VEER
ENOUGH OVER NRN LAKE MI...SOME LIGHT LES MAY AFFECT PORTIONS OF
MENOMINEE COUNTY.
ATTENTION THEN TURNS TO NEXT CLIPPER SHORTWAVE DROPPING THRU THE
UPPER GREAT LAKES SAT NIGHT/SUN. -SN ASSOCIATED WITH FEATURE SHOULD
SPREAD INTO THE AREA SAT AFTN/EVENING...AND IT LOOKS LIKE THERE WILL
BE A QUICK PERIOD OF LAKE ENHANCEMENT OFF LAKE MI IN SOUTHERLY
FLOW...LEADING TO A POTENTIAL ADVY EVENT. A VERY BRIEF SHOT OF
ARCTIC AIR FOLLOWING SYSTEM WILL PROBABLY RESULT IN A SHORT DURATION
BOUT OF MDT TO POSSIBLY HVY LAKE ENHANCED SNOW FOR NORTHWEST AND
NORTHEAST UPPER MI LATE SAT NIGHT/EARLY SUNDAY AS WIND SHIFTS NW. AS
WINDS VEER AROUND TO THE N OR NE WITH SFC HIGH PRES PASSING ACROSS
NRN ONTARIO...LIGHTER LES WILL AGAIN SHIFT TO AFFECT MORE OF NRN
UPPER MI SUN AFTN/EVENING.
FCST IS MUCH MORE UNCERTAIN HEADING INTO MON/TUE AS MEDIUM RANGE
MODELS ARE HAVING TROUBLE WITH SEVERAL SHORTWAVES IN THE WNW FLOW.
GIVEN THE UNCERTAINTY FROM TODAYS MODEL RUNS AND PREVIOUS RUNS...A
SIMPLE CONSENSUS WILL BE UTILIZED MON/TUE. DEPENDING ON
STRENGTH/TRACK OF THE WAVES...THERE MAY BE A COUPLE OF PERIODS OF
WIDESPREAD -SN AS WELL AS LAKE ENHANCEMENT DEPENDING ON WIND
DIRECTION.
HIGH UNCERTAINTY CONTINUES WED AS ECMWF SHOWS THE POSSIBLE MID WEEK
WARMUP ALLUDED TO EARLIER...WHILE THE GFS DUMPS ARCTIC AIR BACK INTO
THE AREA. AT 00Z THU...850MB TEMPS RANGE FROM ROUGHLY AROUND -2C
WITH THE ECWMF TO -20C WITH THE GFS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1228 AM EST THU DEC 12 2013
CMX...AS THE LLVL FLOW BACKS TOWARD THE SW EARLY THIS MRNG WITH
PASSAGE OF SFC HI PRES TO THE S...EXPECT THE HEAVIER SHSN TO SHIFT
TO THE N OF THIS LOCATION. SO TREND TOWARD MVFR CONDITIONS STILL
SEEMS ON TRACK. BUT THERE IS SOME UNCERTAINTY ON HOW FAR N THE
HEAVIER BANDS WL SHIFT...SO MAINTAINED A MENTION OF SOME OCNL IFR
VSBYS FOR MOST OF THE FIRST 6 HRS OF THE FCST. AS THE WINDS VEER
AGAIN MORE TO THE WNW AND TURN GUSTY LATER THIS MRNG...MORE
SHSN/BLSN WL RETURN ALONG WITH IFR TO PERHAPS LIFR CONDITIONS THRU
THIS EVNG.
FOR KSAW/KIWD...A WSW LLVL FLOW OF DRY UNMODIFIED ARCTIC AIR WL
RESULT IN VFR CONDITIONS THRU SUNRISE AT THESE 2 LOCATIONS. AS THE
FLOW VEERS MORE TO THE WNW LATER THIS MRNG...SOME LOWER MVFR CIGS WL
LIKELY RETURN TO IWD. BUT THE DOWNSLOPE NATURE OF THIS FLOW INTO SAW
SHOULD RESULT IN MORE PERSISTENT VFR CONDITIONS THERE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EST WED DEC 11 2013
WEST TO NORTHWEST WINDS OF 20-30KTS WILL WEAKEN SLIGHTLY TONIGHT AS
A HIGH PRESSURE RIDGE BRUSHES THE AREA. A WEAK TROUGH MOVING ACROSS
THE AREA ON THURSDAY WILL SHIFT WINDS TO MORE OF A NORTHWESTERLY
DIRECTION THURSDAY AFTERNOON AND TO THE NORTH THURSDAY NIGHT AS
ANOTHER HIGH PRESSURE RIDGE (THIS TIME FROM CENTRAL CANADA) NOSES
INTO WESTERN LAKE SUPERIOR. THIS RIDGE IS EXPECTED TO WEAKEN THE
WINDS BELOW 20KTS. DEPENDING ON THE STRENGTH OF A LOW MOVING ACROSS
LAKE SUPERIOR ON SATURDAY NIGHT AND SUNDAY AND THE STRENGTH OF THE
LOW MOVING UP THE EAST COAST...COULD SEE A INCREASE IN
NORTHWESTERLY WINDS ON SUNDAY TO 25-30KTS. THIS WILL BE SHORT LIVED
AS ANOTHER HIGH SLIDES INTO THE AREA FOR THE BEGINNING OF THE
UPCOMING WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR MIZ002-
004-005-009>013-084.
LAKE EFFECT SNOW ADVISORY UNTIL 9 AM EST THIS MORNING FOR MIZ001-
003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST /5 AM CST/ EARLY
THIS MORNING FOR LSZ162-240>245-248>251-266.
HEAVY FREEZING SPRAY WARNING UNTIL 3 PM EST THIS AFTERNOON FOR
LSZ263>265.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1141 AM MST THU DEC 12 2013
.UPDATE...
QUICK UPDATE TO LOWER MAX TEMPS IN A FEW MAINLY SOUTH OF I-40
PLACES GIVEN ABUNDANT LOW/MID CLOUD COVER AND SOME LIGHT PRECIP.
DIFFICULT TO KNOW HOW LOW TO GO WITH WAA OCCURRING. LATEST
THOUGHTS WILL BE OUT SHORTLY.
34
&&
.PREV DISCUSSION...1055 AM MST THU DEC 12 2013...
.AVIATION...
18Z TAF CYCLE
COMPLICATED WEATHER SCENARIO FOR AREA TERMINAL SITES TODAY AND
TONIGHT. INITIAL STREAM OF SUBTROPICAL MOISTURE HAS ALLOWED
PRECIPITATION TO BREAK OUT OVER SOUTHERN AND EASTERN AREAS. MAINLY
HIGHER ELEVATION SNOW WITH RAIN ACROSS THE LOW AND MID LEVELS. CANT
RULE OUT MVFR CIGS/VIS RESTRICTIONS IN THE HEART OF THE
SUBTROPICAL FETCH BUT THE MAIN LOWERING OF CIGS AND VIS WILL COME
TONIGHT AS THE UPPER LEVEL LOW TRACKS OVER THE AREA. SNOW LEVELS
WILL BE LOWER TONIGHT AND MOST LIKELY IMPACT GUP/AEG/ABQ. THE
FORECAST TRICKINESS LIES WITH THE MODELLING. MODELS ARE NOT
CONSISTENT AMONGST EACH OTHER. DECIDED TO GO WITH THE MORE BULLISH
NAM APPROACH FOR THE PREVIOUSLY MENTIONED SITES. GFS IS PRIMARILY DRY.
ALSO DECIDED TO KEEP THE POSSIBLE LOW CIG/FOG GENERATION AT ROW
FOLLOWING THE SUBTROPICAL MOISTURE SURGE. COULD GET SOME BRIEF
CLEARING THERE WHICH WOULD ALLOW THE HIGHER LEFTOVER SFC DEWPOINTS
TO FORM VERY LOW CIGS/FG. DIDNT GO HOG WILD AT THIS TIME AND
USING MVFR CIGS/VIS AS A PLACEHOLDER THERE. IF THE NAM MODEL IS
CORRECT THEN AEG/ABQ WOULD SEE IFR AND POSSIBLY LIFR CONDITIONS
DUE TO SNOWFALL. MAIN PERIOD FOR THE PRECIP AT ABQ/AEG RANGES BTWN
8Z TO 15Z. IF THE NAM MODEL IS CORRECT POSSIBLE AWW SNOW AMTS
ALTHOUGH IT MIGHT BE A BIT HARDER TO ACCUM SNOW ON PAVEMENT.
50
.PREV DISCUSSION...303 AM MST THU DEC 12 2013...
WITH THE EXCEPTION OF A BRIEF BOUT OF RAIN/SNOW TODAY/TONIGHT ACROSS
CENTRAL AND WESTERN NM THE OVERALL PATTERN WILL REMAIN RELATIVELY
TRANQUIL THRU THE NEXT 7 DAYS. CURRENTLY A DEEP FETCH OF SUBTROPICAL
MOISTURE SURGING NE OUT OF THE EQUATORIAL PACIFIC WILL SLIDE OVER
SOUTHERN NM AHEAD OF A WEAK UPPER LOW OVER SOCA. THE LATEST HRRR
AND RUC SOLUTIONS SLOW DOWN TIMING OF PRECIP FOR TODAY SO LOWERED
POPS SUBSTANTIALLY THIS MORNING. THE WPC PROBABILISTIC QPF (PQPF)
INDICATES THE BEST SHOT FOR MEASURABLE IN THE SE WILL BE NOON TO
EARLY EVENING. 700MB WARM ADVECTION WITH THIS FETCH WILL RAISE
SNOW LEVELS TO ABOVE 9000 FT. TEMPS EXPECTED TO WARM ABOVE FREEZING
BY THE TIME PRECIP ARRIVES OVER THE AREA THUS SNOW ACCUMS WILL BE
ABOVE RUIDOSO.
MADE SOME NOTABLE CHANGES TO POP DISTRIBUTION FOR CENTRAL/WESTERN
NM LATE TODAY AND TONIGHT. TRENDED TOWARD SREF/GEFS AND WPC PQPF...
WHICH FOCUSES GREATEST CHANCES ALONG THE CONT DVD TONIGHT THEN THE
CENTRAL MT CHAIN/ABQ METRO AREA EARLY FRIDAY. COLD ADVECTION WITH
THE UPPER COLD CORE WILL ALLOW FOR RAIN TO SNOW...HOWEVER QPF IS
LIGHT...SO EXPECT HIGHEST SNOW AMOUNTS OVER HIGHEST TERRAIN. WILL
ISSUE SPS AGAIN SINCE CONFIDENCE ON TIMING/LOCATION OF COLD AIR
AND PRECIP IS TOO LOW FOR ANY ADVISORIES. ACCUMS LOOK MARGINAL TOO
EVEN IF BEST PRECIP COINCIDES WITH COLD AIR AND INSTABILITY.
AFTER THIS QUICK HIT OF RAIN/SNOW COLDER TEMPS WILL AGAIN SLIDE OVER
THE STATE THIS WEEKEND WITH A SERIES OF WEAK WAVES IN NW FLOW.
OTHERWISE IT WILL REMAIN QUIET THRU NEXT WEEK AS TEMPS MODERATE BACK
NEAR TO SLIGHTLY ABV NORMAL. PERIODIC GUSTY BREEZES IN NW FLOW ARE
LIKELY ALONG WIND PRONE AREAS EAST OF THE CENTRAL MT CHAIN.
GUYER
.FIRE WEATHER...
POOR VENTILATION IS EXPECTED AREAWIDE TODAY AS A LOW PRESSURE SYSTEM
THAT HAS BEEN STALLED OFF THE UPPER BAJA COAST BEGINS TO SHIFT
NORTHEASTWARD TOWARD NM. THE BULK OF THE MOISTURE WITH THE SYSTEM
WILL BE ASSOCIATED WITH THE SUBTROPICAL JET...WHICH WILL SHIFT
EASTWARD ACROSS SOUTHERN NM TODAY. MODELS AND OUR FORECAST GRIDS
HAVE SLOWED THE ARRIVAL OF THIS MOISTURE...WITH RAIN AND VERY HIGH
MOUNTAIN SNOWS FAVORING LOCATIONS ALONG AND SOUTH OF HIGHWAY 60 THIS
AFTERNOON. INSTABILITY LOOKS SUFFICIENT FOR A FEW THUNDERSTORMS TO
DEVELOP OVER THE SW MOUNTAINS THIS AFTERNOON...TOO. THE UPPER LEVEL
LOW AND A PACIFIC COLD FRONT ARE THEN PROGGED TO BRING MODEST
MOISTURE AND COLDER TEMPERATURES TO WESTERN AREAS...AND TO A LESSER
EXTENT CENTRAL AND SOUTHERN AREAS...TONIGHT. THE BAJA SYSTEM WILL
EXIT EASTWARD DURING THE AFTERNOON FRIDAY...BUT A SECONDARY UPPER
LOW RIGHT ON ITS HEELS WILL CROSS THE AREA FROM THE NORTHWEST...
KEEPING SHOWERS IN THE FORECAST FOR CENTRAL AND WESTERN AREAS FRIDAY
AND FRIDAY NIGHT. BY LATE FRIDAY...A FEW INCHES OF SNOW ACCUMULATION
WILL BE POSSIBLE IN THE WESTERN MOUNTAINS...WITH LIGHTER AMOUNTS
ACROSS THE REMAINDER OF THE HIGH TERRAIN. FROM THURSDAY THROUGH
FRIDAY NIGHT...LIQUID AND LIQUID EQUIVALENT PRECIPITATION SHOULD
TOTAL AROUND A QUARTER INCH ACROSS SOUTHERN PARTS OF THE FIRE
WEATHER FORECAST AREA...WITH A TENTH OF AN INCH POSSIBLE IN
LOCATIONS AS FAR NORTH AS THE CHUSKA MOUNTAINS AND ALBUQUERQUE. A
FEW HUNDREDTHS OF AN INCH WILL BE POSSIBLE FROM FARMINGTON TO SANTA
FE AND PORTALES.
IN THE WAKE OF THE PACIFIC COLD FRONT...W AND NW WINDS WILL PICK UP
FRIDAY AS A SPEED MAXIMUM IN THE POLAR JET ROUNDS THE BASE OF THE
SECONDARY UPPER TROUGH AND CROSSES SOUTHERN NM. MEANWHILE...A
SURFACE LOW WILL SHIFT SOUTHEASTWARD FROM SE CO OVER THE TX
PANHANDLE KEEPING THE SURFACE PRESSURE GRADIENT TIGHT ACROSS THE
PLAINS. THE STRONGEST NW WINDS SHOULD BE FOUND ALONG AND SOUTH OF
I-40...WITH GUSTS FROM 40 TO PERHAPS 50 MPH EAST OF THE
SANDIA/MANZANO AND GALLINAS MOUNTAINS TO THE PECOS RIVER. BREEZY
CONDITIONS WILL EXTEND EAST OF THERE TO THE TX BORDER.
FORTUNATELY...HUMIDITIES WILL REMAIN ABOVE CRITICAL THRESHOLDS.
BECAUSE OF THE STRONGER WINDS...THERE WILL BE SOME VENTILATION
IMPROVEMENT FRIDAY ALONG AND SOUTH OF I-40...WITH POOR VENTILATION
LINGERING ACROSS MUCH OF THE NORTH.
ONE LAST WEAK AND DRY UPPER TROUGH WILL DIVE SOUTHEASTWARD ACROSS
THE FORECAST AREA SATURDAY...PROMPTLY BEHIND FRIDAYS SECONDARY
SYSTEM. THIS THIRD TROUGH WILL KEEP COLD AIR ADVECTION IN PLACE FOR
ONE LAST DAY. HIGH TEMPERATURES ARE EXPECTED TO BOTTOM OUT SATURDAY
AROUND 3 TO 10 DEGREES BELOW NORMAL. VENTILATION WILL BE POOR
AREAWIDE...EXCEPT FOR SOME IMPROVEMENT ACROSS THE FAR EASTERN PLAINS
DUE TO GUSTY NORTH WINDS LINGERING BEHIND A BACK DOOR COLD FRONT
THAT WILL SINK SOUTHWARD THROUGH THE PLAINS FRIDAY NIGHT.
DRY NW FLOW ALOFT WILL PERSIST THROUGH THE MIDDLE OF THE COMING
WEEK. WEATHER SYSTEMS WILL PASS FAR ENOUGH NORTH TO KEEP
PRECIPITATION OUT OF THE FORECAST FOR NORTHERN AND CENTRAL NM. A
WARMING TREND WILL DEVELOP SUNDAY THROUGH TUESDAY WITH HIGH
TEMPERATURES REACHING ABOVE NORMAL IN MOST LOCATIONS AS EARLY AS
MONDAY. A BACK DOOR COLD FRONT SHOULD THEN DROP SOUTHWARD THROUGH
THE PLAINS TUESDAY NIGHT COOLING TEMPERATURES ACROSS THE EAST FOR
WEDNESDAY. OTHERWISE...VENTILATION WILL GENERALLY BE POOR...EXCEPT
FOR PERIODS OF IMPROVEMENT ACROSS THE EAST CENTRAL PLAINS.
44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
34
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1055 AM MST THU DEC 12 2013
.AVIATION...
18Z TAF CYCLE
COMPLICATED WEATHER SCENARIO FOR AREA TERMINAL SITES TODAY AND
TONIGHT. INITIAL STREAM OF SUBTROPICAL MOISTURE HAS ALLOWED
PRECIPITATION TO BREAK OUT OVER SOUTHERN AND EASTERN AREAS. MAINLY
HIGHER ELEVATION SNOW WITH RAIN ACROSS THE LOW AND MID LEVELS. CANT
RULE OUT MVFR CIGS/VIS RESTRICTIONS IN THE HEART OF THE
SUBTROPICAL FETCH BUT THE MAIN LOWERING OF CIGS AND VIS WILL COME
TONIGHT AS THE UPPER LEVEL LOW TRACKS OVER THE AREA. SNOW LEVELS
WILL BE LOWER TONIGHT AND MOST LIKELY IMPACT GUP/AEG/ABQ. THE
FORECAST TRICKINESS LIES WITH THE MODELLING. MODELS ARE NOT
CONSISTENT AMONGST EACH OTHER. DECIDED TO GO WITH THE MORE BULLISH
NAM APPROACH FOR THE PREVIOUSLY MENTIONED SITES. GFS IS PRIMARILY DRY.
ALSO DECIDED TO KEEP THE POSSIBLE LOW CIG/FOG GENERATION AT ROW
FOLLOWING THE SUBTROPICAL MOISTURE SURGE. COULD GET SOME BRIEF
CLEARING THERE WHICH WOULD ALLOW THE HIGHER LEFTOVER SFC DEWPOINTS
TO FORM VERY LOW CIGS/FG. DIDNT GO HOG WILD AT THIS TIME AND
USING MVFR CIGS/VIS AS A PLACEHOLDER THERE. IF THE NAM MODEL IS
CORRECT THEN AEG/ABQ WOULD SEE IFR AND POSSIBLY LIFR CONDITIONS
DUE TO SNOWFALL. MAIN PERIOD FOR THE PRECIP AT ABQ/AEG RANGES BTWN
8Z TO 15Z. IF THE NAM MODEL IS CORRECT POSSIBLE AWW SNOW AMTS
ALTHOUGH IT MIGHT BE A BIT HARDER TO ACCUM SNOW ON PAVEMENT.
50
&&
.PREV DISCUSSION...303 AM MST THU DEC 12 2013...
WITH THE EXCEPTION OF A BRIEF BOUT OF RAIN/SNOW TODAY/TONIGHT ACROSS
CENTRAL AND WESTERN NM THE OVERALL PATTERN WILL REMAIN RELATIVELY
TRANQUIL THRU THE NEXT 7 DAYS. CURRENTLY A DEEP FETCH OF SUBTROPICAL
MOISTURE SURGING NE OUT OF THE EQUATORIAL PACIFIC WILL SLIDE OVER
SOUTHERN NM AHEAD OF A WEAK UPPER LOW OVER SOCA. THE LATEST HRRR
AND RUC SOLUTIONS SLOW DOWN TIMING OF PRECIP FOR TODAY SO LOWERED
POPS SUBSTANTIALLY THIS MORNING. THE WPC PROBABILISTIC QPF (PQPF)
INDICATES THE BEST SHOT FOR MEASURABLE IN THE SE WILL BE NOON TO
EARLY EVENING. 700MB WARM ADVECTION WITH THIS FETCH WILL RAISE
SNOW LEVELS TO ABOVE 9000 FT. TEMPS EXPECTED TO WARM ABOVE FREEZING
BY THE TIME PRECIP ARRIVES OVER THE AREA THUS SNOW ACCUMS WILL BE
ABOVE RUIDOSO.
MADE SOME NOTABLE CHANGES TO POP DISTRIBUTION FOR CENTRAL/WESTERN
NM LATE TODAY AND TONIGHT. TRENDED TOWARD SREF/GEFS AND WPC PQPF...
WHICH FOCUSES GREATEST CHANCES ALONG THE CONT DVD TONIGHT THEN THE
CENTRAL MT CHAIN/ABQ METRO AREA EARLY FRIDAY. COLD ADVECTION WITH
THE UPPER COLD CORE WILL ALLOW FOR RAIN TO SNOW...HOWEVER QPF IS
LIGHT...SO EXPECT HIGHEST SNOW AMOUNTS OVER HIGHEST TERRAIN. WILL
ISSUE SPS AGAIN SINCE CONFIDENCE ON TIMING/LOCATION OF COLD AIR
AND PRECIP IS TOO LOW FOR ANY ADVISORIES. ACCUMS LOOK MARGINAL TOO
EVEN IF BEST PRECIP COINCIDES WITH COLD AIR AND INSTABILITY.
AFTER THIS QUICK HIT OF RAIN/SNOW COLDER TEMPS WILL AGAIN SLIDE OVER
THE STATE THIS WEEKEND WITH A SERIES OF WEAK WAVES IN NW FLOW.
OTHERWISE IT WILL REMAIN QUIET THRU NEXT WEEK AS TEMPS MODERATE BACK
NEAR TO SLIGHTLY ABV NORMAL. PERIODIC GUSTY BREEZES IN NW FLOW ARE
LIKELY ALONG WIND PRONE AREAS EAST OF THE CENTRAL MT CHAIN.
GUYER
.FIRE WEATHER...
POOR VENTILATION IS EXPECTED AREAWIDE TODAY AS A LOW PRESSURE SYSTEM
THAT HAS BEEN STALLED OFF THE UPPER BAJA COAST BEGINS TO SHIFT
NORTHEASTWARD TOWARD NM. THE BULK OF THE MOISTURE WITH THE SYSTEM
WILL BE ASSOCIATED WITH THE SUBTROPICAL JET...WHICH WILL SHIFT
EASTWARD ACROSS SOUTHERN NM TODAY. MODELS AND OUR FORECAST GRIDS
HAVE SLOWED THE ARRIVAL OF THIS MOISTURE...WITH RAIN AND VERY HIGH
MOUNTAIN SNOWS FAVORING LOCATIONS ALONG AND SOUTH OF HIGHWAY 60 THIS
AFTERNOON. INSTABILITY LOOKS SUFFICIENT FOR A FEW THUNDERSTORMS TO
DEVELOP OVER THE SW MOUNTAINS THIS AFTERNOON...TOO. THE UPPER LEVEL
LOW AND A PACIFIC COLD FRONT ARE THEN PROGGED TO BRING MODEST
MOISTURE AND COLDER TEMPERATURES TO WESTERN AREAS...AND TO A LESSER
EXTENT CENTRAL AND SOUTHERN AREAS...TONIGHT. THE BAJA SYSTEM WILL
EXIT EASTWARD DURING THE AFTERNOON FRIDAY...BUT A SECONDARY UPPER
LOW RIGHT ON ITS HEELS WILL CROSS THE AREA FROM THE NORTHWEST...
KEEPING SHOWERS IN THE FORECAST FOR CENTRAL AND WESTERN AREAS FRIDAY
AND FRIDAY NIGHT. BY LATE FRIDAY...A FEW INCHES OF SNOW ACCUMULATION
WILL BE POSSIBLE IN THE WESTERN MOUNTAINS...WITH LIGHTER AMOUNTS
ACROSS THE REMAINDER OF THE HIGH TERRAIN. FROM THURSDAY THROUGH
FRIDAY NIGHT...LIQUID AND LIQUID EQUIVALENT PRECIPITATION SHOULD
TOTAL AROUND A QUARTER INCH ACROSS SOUTHERN PARTS OF THE FIRE
WEATHER FORECAST AREA...WITH A TENTH OF AN INCH POSSIBLE IN
LOCATIONS AS FAR NORTH AS THE CHUSKA MOUNTAINS AND ALBUQUERQUE. A
FEW HUNDREDTHS OF AN INCH WILL BE POSSIBLE FROM FARMINGTON TO SANTA
FE AND PORTALES.
IN THE WAKE OF THE PACIFIC COLD FRONT...W AND NW WINDS WILL PICK UP
FRIDAY AS A SPEED MAXIMUM IN THE POLAR JET ROUNDS THE BASE OF THE
SECONDARY UPPER TROUGH AND CROSSES SOUTHERN NM. MEANWHILE...A
SURFACE LOW WILL SHIFT SOUTHEASTWARD FROM SE CO OVER THE TX
PANHANDLE KEEPING THE SURFACE PRESSURE GRADIENT TIGHT ACROSS THE
PLAINS. THE STRONGEST NW WINDS SHOULD BE FOUND ALONG AND SOUTH OF
I-40...WITH GUSTS FROM 40 TO PERHAPS 50 MPH EAST OF THE
SANDIA/MANZANO AND GALLINAS MOUNTAINS TO THE PECOS RIVER. BREEZY
CONDITIONS WILL EXTEND EAST OF THERE TO THE TX BORDER.
FORTUNATELY...HUMIDITIES WILL REMAIN ABOVE CRITICAL THRESHOLDS.
BECAUSE OF THE STRONGER WINDS...THERE WILL BE SOME VENTILATION
IMPROVEMENT FRIDAY ALONG AND SOUTH OF I-40...WITH POOR VENTILATION
LINGERING ACROSS MUCH OF THE NORTH.
ONE LAST WEAK AND DRY UPPER TROUGH WILL DIVE SOUTHEASTWARD ACROSS
THE FORECAST AREA SATURDAY...PROMPTLY BEHIND FRIDAYS SECONDARY
SYSTEM. THIS THIRD TROUGH WILL KEEP COLD AIR ADVECTION IN PLACE FOR
ONE LAST DAY. HIGH TEMPERATURES ARE EXPECTED TO BOTTOM OUT SATURDAY
AROUND 3 TO 10 DEGREES BELOW NORMAL. VENTILATION WILL BE POOR
AREAWIDE...EXCEPT FOR SOME IMPROVEMENT ACROSS THE FAR EASTERN PLAINS
DUE TO GUSTY NORTH WINDS LINGERING BEHIND A BACK DOOR COLD FRONT
THAT WILL SINK SOUTHWARD THROUGH THE PLAINS FRIDAY NIGHT.
DRY NW FLOW ALOFT WILL PERSIST THROUGH THE MIDDLE OF THE COMING
WEEK. WEATHER SYSTEMS WILL PASS FAR ENOUGH NORTH TO KEEP
PRECIPITATION OUT OF THE FORECAST FOR NORTHERN AND CENTRAL NM. A
WARMING TREND WILL DEVELOP SUNDAY THROUGH TUESDAY WITH HIGH
TEMPERATURES REACHING ABOVE NORMAL IN MOST LOCATIONS AS EARLY AS
MONDAY. A BACK DOOR COLD FRONT SHOULD THEN DROP SOUTHWARD THROUGH
THE PLAINS TUESDAY NIGHT COOLING TEMPERATURES ACROSS THE EAST FOR
WEDNESDAY. OTHERWISE...VENTILATION WILL GENERALLY BE POOR...EXCEPT
FOR PERIODS OF IMPROVEMENT ACROSS THE EAST CENTRAL PLAINS.
44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
500 AM MST THU DEC 12 2013
.AVIATION...
12Z TAF CYCLE
RAIN AND HIGH TERRAIN SNOW WILL MOVE INTO THE AREA FROM THE SOUTH
TODAY AS AN UPPER LEVEL LOW PRESSURE SYSTEM APPROACHES FROM THE
SW. TONIGHT...MODELS DEPICT THE INITIAL WAVE OF PRECIPITATION
SHIFTING EAST OF NEW MEXICO WITH MORE ACTIVITY IN THE FORM OF
MAINLY SNOW SHIFTING INTO CENTRAL AND WESTERN AREAS FROM THE WEST
WITH THE WEAKENING UPPER LEVEL STORM SYSTEM AND A PACIFIC COLD
FRONT. A FEW INCHES OF SNOW ACCUMULATION WILL BE POSSIBLE IN THE
WESTERN MOUNTAINS OVERNIGHT WITH LIGHTER AMOUNTS AT LOWER
ELEVATIONS ALONG AND W OF THE CENTRAL MT CHAIN. MVFR CONDITIONS
SHOULD BE COMMON WITH THE PRECIPITATION AS IT STARTS TODAY...THEN
PERIODS OF IFR CONDITIONS ARE EXPECTED ACROSS MUCH OF
WESTERN...CENTRAL AND SOUTHEAST PORTIONS OF THE FORECAST AREA
TONIGHT. MODELS SUGGEST FOG AND LOW CLOUDS COULD PRODUCE LIFR
CONDITIONS LATE TONIGHT IN ROSWELL. FLIGHT CATEGORY RESTRICTIONS
ARE EXPECTED TO LINGER IN MANY LOCATIONS WELL INTO FRIDAY AS THE
BAJA SYSTEM GRADUALLY EXITS AND ANOTHER WEAKER UPPER TROUGH MOVES
IN FROM THE NW KEEPING SHOWERS ACTIVE. NW WINDS WILL ALSO
STRENGTHEN FRIDAY...ESPECIALLY E OF THE CENTRAL MTS.
44
&&
.PREV DISCUSSION...303 AM MST THU DEC 12 2013...
WITH THE EXCEPTION OF A BRIEF BOUT OF RAIN/SNOW TODAY/TONIGHT ACROSS
CENTRAL AND WESTERN NM THE OVERALL PATTERN WILL REMAIN RELATIVELY
TRANQUIL THRU THE NEXT 7 DAYS. CURRENTLY A DEEP FETCH OF SUBTROPICAL
MOISTURE SURGING NE OUT OF THE EQUATORIAL PACIFIC WILL SLIDE OVER
SOUTHERN NM AHEAD OF A WEAK UPPER LOW OVER SOCA. THE LATEST HRRR
AND RUC SOLUTIONS SLOW DOWN TIMING OF PRECIP FOR TODAY SO LOWERED
POPS SUBSTANTIALLY THIS MORNING. THE WPC PROBABILISTIC QPF (PQPF)
INDICATES THE BEST SHOT FOR MEASURABLE IN THE SE WILL BE NOON TO
EARLY EVENING. 700MB WARM ADVECTION WITH THIS FETCH WILL RAISE
SNOW LEVELS TO ABOVE 9000 FT. TEMPS EXPECTED TO WARM ABOVE FREEZING
BY THE TIME PRECIP ARRIVES OVER THE AREA THUS SNOW ACCUMS WILL BE
ABOVE RUIDOSO.
MADE SOME NOTABLE CHANGES TO POP DISTRIBUTION FOR CENTRAL/WESTERN
NM LATE TODAY AND TONIGHT. TRENDED TOWARD SREF/GEFS AND WPC PQPF...
WHICH FOCUSES GREATEST CHANCES ALONG THE CONT DVD TONIGHT THEN THE
CENTRAL MT CHAIN/ABQ METRO AREA EARLY FRIDAY. COLD ADVECTION WITH
THE UPPER COLD CORE WILL ALLOW FOR RAIN TO SNOW...HOWEVER QPF IS
LIGHT...SO EXPECT HIGHEST SNOW AMOUNTS OVER HIGHEST TERRAIN. WILL
ISSUE SPS AGAIN SINCE CONFIDENCE ON TIMING/LOCATION OF COLD AIR
AND PRECIP IS TOO LOW FOR ANY ADVISORIES. ACCUMS LOOK MARGINAL TOO
EVEN IF BEST PRECIP COINCIDES WITH COLD AIR AND INSTABILITY.
AFTER THIS QUICK HIT OF RAIN/SNOW COLDER TEMPS WILL AGAIN SLIDE OVER
THE STATE THIS WEEKEND WITH A SERIES OF WEAK WAVES IN NW FLOW.
OTHERWISE IT WILL REMAIN QUIET THRU NEXT WEEK AS TEMPS MODERATE BACK
NEAR TO SLIGHTLY ABV NORMAL. PERIODIC GUSTY BREEZES IN NW FLOW ARE
LIKELY ALONG WIND PRONE AREAS EAST OF THE CENTRAL MT CHAIN.
GUYER
.FIRE WEATHER...
POOR VENTILATION IS EXPECTED AREAWIDE TODAY AS A LOW PRESSURE SYSTEM
THAT HAS BEEN STALLED OFF THE UPPER BAJA COAST BEGINS TO SHIFT
NORTHEASTWARD TOWARD NM. THE BULK OF THE MOISTURE WITH THE SYSTEM
WILL BE ASSOCIATED WITH THE SUBTROPICAL JET...WHICH WILL SHIFT
EASTWARD ACROSS SOUTHERN NM TODAY. MODELS AND OUR FORECAST GRIDS
HAVE SLOWED THE ARRIVAL OF THIS MOISTURE...WITH RAIN AND VERY HIGH
MOUNTAIN SNOWS FAVORING LOCATIONS ALONG AND SOUTH OF HIGHWAY 60 THIS
AFTERNOON. INSTABILITY LOOKS SUFFICIENT FOR A FEW THUNDERSTORMS TO
DEVELOP OVER THE SW MOUNTAINS THIS AFTERNOON...TOO. THE UPPER LEVEL
LOW AND A PACIFIC COLD FRONT ARE THEN PROGGED TO BRING MODEST
MOISTURE AND COLDER TEMPERATURES TO WESTERN AREAS...AND TO A LESSER
EXTENT CENTRAL AND SOUTHERN AREAS...TONIGHT. THE BAJA SYSTEM WILL
EXIT EASTWARD DURING THE AFTERNOON FRIDAY...BUT A SECONDARY UPPER
LOW RIGHT ON ITS HEELS WILL CROSS THE AREA FROM THE NORTHWEST...
KEEPING SHOWERS IN THE FORECAST FOR CENTRAL AND WESTERN AREAS FRIDAY
AND FRIDAY NIGHT. BY LATE FRIDAY...A FEW INCHES OF SNOW ACCUMULATION
WILL BE POSSIBLE IN THE WESTERN MOUNTAINS...WITH LIGHTER AMOUNTS
ACROSS THE REMAINDER OF THE HIGH TERRAIN. FROM THURSDAY THROUGH
FRIDAY NIGHT...LIQUID AND LIQUID EQUIVALENT PRECIPITATION SHOULD
TOTAL AROUND A QUARTER INCH ACROSS SOUTHERN PARTS OF THE FIRE
WEATHER FORECAST AREA...WITH A TENTH OF AN INCH POSSIBLE IN
LOCATIONS AS FAR NORTH AS THE CHUSKA MOUNTAINS AND ALBUQUERQUE. A
FEW HUNDREDTHS OF AN INCH WILL BE POSSIBLE FROM FARMINGTON TO SANTA
FE AND PORTALES.
IN THE WAKE OF THE PACIFIC COLD FRONT...W AND NW WINDS WILL PICK UP
FRIDAY AS A SPEED MAXIMUM IN THE POLAR JET ROUNDS THE BASE OF THE
SECONDARY UPPER TROUGH AND CROSSES SOUTHERN NM. MEANWHILE...A
SURFACE LOW WILL SHIFT SOUTHEASTWARD FROM SE CO OVER THE TX
PANHANDLE KEEPING THE SURFACE PRESSURE GRADIENT TIGHT ACROSS THE
PLAINS. THE STRONGEST NW WINDS SHOULD BE FOUND ALONG AND SOUTH OF
I-40...WITH GUSTS FROM 40 TO PERHAPS 50 MPH EAST OF THE
SANDIA/MANZANO AND GALLINAS MOUNTAINS TO THE PECOS RIVER. BREEZY
CONDITIONS WILL EXTEND EAST OF THERE TO THE TX BORDER.
FORTUNATELY...HUMIDITIES WILL REMAIN ABOVE CRITICAL THRESHOLDS.
BECAUSE OF THE STRONGER WINDS...THERE WILL BE SOME VENTILATION
IMPROVEMENT FRIDAY ALONG AND SOUTH OF I-40...WITH POOR VENTILATION
LINGERING ACROSS MUCH OF THE NORTH.
ONE LAST WEAK AND DRY UPPER TROUGH WILL DIVE SOUTHEASTWARD ACROSS
THE FORECAST AREA SATURDAY...PROMPTLY BEHIND FRIDAYS SECONDARY
SYSTEM. THIS THIRD TROUGH WILL KEEP COLD AIR ADVECTION IN PLACE FOR
ONE LAST DAY. HIGH TEMPERATURES ARE EXPECTED TO BOTTOM OUT SATURDAY
AROUND 3 TO 10 DEGREES BELOW NORMAL. VENTILATION WILL BE POOR
AREAWIDE...EXCEPT FOR SOME IMPROVEMENT ACROSS THE FAR EASTERN PLAINS
DUE TO GUSTY NORTH WINDS LINGERING BEHIND A BACK DOOR COLD FRONT
THAT WILL SINK SOUTHWARD THROUGH THE PLAINS FRIDAY NIGHT.
DRY NW FLOW ALOFT WILL PERSIST THROUGH THE MIDDLE OF THE COMING
WEEK. WEATHER SYSTEMS WILL PASS FAR ENOUGH NORTH TO KEEP
PRECIPITATION OUT OF THE FORECAST FOR NORTHERN AND CENTRAL NM. A
WARMING TREND WILL DEVELOP SUNDAY THROUGH TUESDAY WITH HIGH
TEMPERATURES REACHING ABOVE NORMAL IN MOST LOCATIONS AS EARLY AS
MONDAY. A BACK DOOR COLD FRONT SHOULD THEN DROP SOUTHWARD THROUGH
THE PLAINS TUESDAY NIGHT COOLING TEMPERATURES ACROSS THE EAST FOR
WEDNESDAY. OTHERWISE...VENTILATION WILL GENERALLY BE POOR...EXCEPT
FOR PERIODS OF IMPROVEMENT ACROSS THE EAST CENTRAL PLAINS.
44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
303 AM MST THU DEC 12 2013
.DISCUSSION...
WITH THE EXCEPTION OF A BRIEF BOUT OF RAIN/SNOW TODAY/TONIGHT ACROSS
CENTRAL AND WESTERN NM THE OVERALL PATTERN WILL REMAIN RELATIVELY
TRANQUIL THRU THE NEXT 7 DAYS. CURRENTLY A DEEP FETCH OF SUBTROPICAL
MOISTURE SURGING NE OUT OF THE EQUATORIAL PACIFIC WILL SLIDE OVER
SOUTHERN NM AHEAD OF A WEAK UPPER LOW OVER SOCA. THE LATEST HRRR
AND RUC SOLUTIONS SLOW DOWN TIMING OF PRECIP FOR TODAY SO LOWERED
POPS SUBSTANTIALLY THIS MORNING. THE WPC PROBABILISTIC QPF (PQPF)
INDICATES THE BEST SHOT FOR MEASURABLE IN THE SE WILL BE NOON TO
EARLY EVENING. 700MB WARM ADVECTION WITH THIS FETCH WILL RAISE
SNOW LEVELS TO ABOVE 9000 FT. TEMPS EXPECTED TO WARM ABOVE FREEZING
BY THE TIME PRECIP ARRIVES OVER THE AREA THUS SNOW ACCUMS WILL BE
ABOVE RUIDOSO.
MADE SOME NOTABLE CHANGES TO POP DISTRIBUTION FOR CENTRAL/WESTERN
NM LATE TODAY AND TONIGHT. TRENDED TOWARD SREF/GEFS AND WPC PQPF...
WHICH FOCUSES GREATEST CHANCES ALONG THE CONT DVD TONIGHT THEN THE
CENTRAL MT CHAIN/ABQ METRO AREA EARLY FRIDAY. COLD ADVECTION WITH
THE UPPER COLD CORE WILL ALLOW FOR RAIN TO SNOW...HOWEVER QPF IS
LIGHT...SO EXPECT HIGHEST SNOW AMOUNTS OVER HIGHEST TERRAIN. WILL
ISSUE SPS AGAIN SINCE CONFIDENCE ON TIMING/LOCATION OF COLD AIR
AND PRECIP IS TOO LOW FOR ANY ADVISORIES. ACCUMS LOOK MARGINAL TOO
EVEN IF BEST PRECIP COINCIDES WITH COLD AIR AND INSTABILITY.
AFTER THIS QUICK HIT OF RAIN/SNOW COLDER TEMPS WILL AGAIN SLIDE OVER
THE STATE THIS WEEKEND WITH A SERIES OF WEAK WAVES IN NW FLOW.
OTHERWISE IT WILL REMAIN QUIET THRU NEXT WEEK AS TEMPS MODERATE BACK
NEAR TO SLIGHTLY ABV NORMAL. PERIODIC GUSTY BREEZES IN NW FLOW ARE
LIKELY ALONG WIND PRONE AREAS EAST OF THE CENTRAL MT CHAIN.
GUYER
&&
.FIRE WEATHER...
POOR VENTILATION IS EXPECTED AREAWIDE TODAY AS A LOW PRESSURE SYSTEM
THAT HAS BEEN STALLED OFF THE UPPER BAJA COAST BEGINS TO SHIFT
NORTHEASTWARD TOWARD NM. THE BULK OF THE MOISTURE WITH THE SYSTEM
WILL BE ASSOCIATED WITH THE SUBTROPICAL JET...WHICH WILL SHIFT
EASTWARD ACROSS SOUTHERN NM TODAY. MODELS AND OUR FORECAST GRIDS
HAVE SLOWED THE ARRIVAL OF THIS MOISTURE...WITH RAIN AND VERY HIGH
MOUNTAIN SNOWS FAVORING LOCATIONS ALONG AND SOUTH OF HIGHWAY 60 THIS
AFTERNOON. INSTABILITY LOOKS SUFFICIENT FOR A FEW THUNDERSTORMS TO
DEVELOP OVER THE SW MOUNTAINS THIS AFTERNOON...TOO. THE UPPER LEVEL
LOW AND A PACIFIC COLD FRONT ARE THEN PROGGED TO BRING MODEST
MOISTURE AND COLDER TEMPERATURES TO WESTERN AREAS...AND TO A LESSER
EXTENT CENTRAL AND SOUTHERN AREAS...TONIGHT. THE BAJA SYSTEM WILL
EXIT EASTWARD DURING THE AFTERNOON FRIDAY...BUT A SECONDARY UPPER
LOW RIGHT ON ITS HEELS WILL CROSS THE AREA FROM THE NORTHWEST...
KEEPING SHOWERS IN THE FORECAST FOR CENTRAL AND WESTERN AREAS FRIDAY
AND FRIDAY NIGHT. BY LATE FRIDAY...A FEW INCHES OF SNOW ACCUMULATION
WILL BE POSSIBLE IN THE WESTERN MOUNTAINS...WITH LIGHTER AMOUNTS
ACROSS THE REMAINDER OF THE HIGH TERRAIN. FROM THURSDAY THROUGH
FRIDAY NIGHT...LIQUID AND LIQUID EQUIVALENT PRECIPITATION SHOULD
TOTAL AROUND A QUARTER INCH ACROSS SOUTHERN PARTS OF THE FIRE
WEATHER FORECAST AREA...WITH A TENTH OF AN INCH POSSIBLE IN
LOCATIONS AS FAR NORTH AS THE CHUSKA MOUNTAINS AND ALBUQUERQUE. A
FEW HUNDREDTHS OF AN INCH WILL BE POSSIBLE FROM FARMINGTON TO SANTA
FE AND PORTALES.
IN THE WAKE OF THE PACIFIC COLD FRONT...W AND NW WINDS WILL PICK UP
FRIDAY AS A SPEED MAXIMUM IN THE POLAR JET ROUNDS THE BASE OF THE
SECONDARY UPPER TROUGH AND CROSSES SOUTHERN NM. MEANWHILE...A
SURFACE LOW WILL SHIFT SOUTHEASTWARD FROM SE CO OVER THE TX
PANHANDLE KEEPING THE SURFACE PRESSURE GRADIENT TIGHT ACROSS THE
PLAINS. THE STRONGEST NW WINDS SHOULD BE FOUND ALONG AND SOUTH OF
I-40...WITH GUSTS FROM 40 TO PERHAPS 50 MPH EAST OF THE
SANDIA/MANZANO AND GALLINAS MOUNTAINS TO THE PECOS RIVER. BREEZY
CONDITIONS WILL EXTEND EAST OF THERE TO THE TX BORDER.
FORTUNATELY...HUMIDITIES WILL REMAIN ABOVE CRITICAL THRESHOLDS.
BECAUSE OF THE STRONGER WINDS...THERE WILL BE SOME VENTILATION
IMPROVEMENT FRIDAY ALONG AND SOUTH OF I-40...WITH POOR VENTILATION
LINGERING ACROSS MUCH OF THE NORTH.
ONE LAST WEAK AND DRY UPPER TROUGH WILL DIVE SOUTHEASTWARD ACROSS
THE FORECAST AREA SATURDAY...PROMPTLY BEHIND FRIDAYS SECONDARY
SYSTEM. THIS THIRD TROUGH WILL KEEP COLD AIR ADVECTION IN PLACE FOR
ONE LAST DAY. HIGH TEMPERATURES ARE EXPECTED TO BOTTOM OUT SATURDAY
AROUND 3 TO 10 DEGREES BELOW NORMAL. VENTILATION WILL BE POOR
AREAWIDE...EXCEPT FOR SOME IMPROVEMENT ACROSS THE FAR EASTERN PLAINS
DUE TO GUSTY NORTH WINDS LINGERING BEHIND A BACK DOOR COLD FRONT
THAT WILL SINK SOUTHWARD THROUGH THE PLAINS FRIDAY NIGHT.
DRY NW FLOW ALOFT WILL PERSIST THROUGH THE MIDDLE OF THE COMING
WEEK. WEATHER SYSTEMS WILL PASS FAR ENOUGH NORTH TO KEEP
PRECIPITATION OUT OF THE FORECAST FOR NORTHERN AND CENTRAL NM. A
WARMING TREND WILL DEVELOP SUNDAY THROUGH TUESDAY WITH HIGH
TEMPERATURES REACHING ABOVE NORMAL IN MOST LOCATIONS AS EARLY AS
MONDAY. A BACK DOOR COLD FRONT SHOULD THEN DROP SOUTHWARD THROUGH
THE PLAINS TUESDAY NIGHT COOLING TEMPERATURES ACROSS THE EAST FOR
WEDNESDAY. OTHERWISE...VENTILATION WILL GENERALLY BE POOR...EXCEPT
FOR PERIODS OF IMPROVEMENT ACROSS THE EAST CENTRAL PLAINS.
44
&&
.AVIATION...
06Z TAF CYCLE
WEATHER SYSTEM OVER NORTHERN BAJA CALIFORNIA SHIFTING TO CENTRAL
ARIZONA OVER THE NEXT 24 HRS. CLOUD COVER BUILDING DECK AOA
BKN/OVC050 INTO SOUTHERN AND WESTERN NM FROM 15Z ONWARD THU
MORNING...WITH CLOUD DECK REACHING EAST TO THE RIO GRANDE AND
NORTH ACROSS INTERSTATE 40 FROM 18Z ONWARD. LOWERING CIGS AND RAIN
AND SNOW SHOWERS WILL PRODUCE EXCURSIONS TO MVFR AND IFR AS CLOUD
COVER BUILDS IN. SCT015/SCT025 GROUPS IN TAFS SERVING AS PLACE
HOLDERS FOR MVFR/IFR CIGS AT GUP...ABQ...AEG...SAF...TCC...AND ROW
THU AFTERNOON AND EVE. LOWERING CIG WILL PRODUCE MT OBSCURATION
FOR THE CONTINENTAL DIVIDE AND CENTRAL MOUNTAIN CHAIN FROM 21Z
ONWARD...WITH CONDITIONS CONTG BEYOND 06Z THU EVENING.
SHY
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 38 19 38 16 / 5 30 5 0
DULCE........................... 40 11 36 7 / 5 20 10 5
CUBA............................ 42 17 39 12 / 5 30 30 10
GALLUP.......................... 43 21 41 12 / 10 40 20 5
EL MORRO........................ 43 20 39 13 / 20 50 20 5
GRANTS.......................... 43 23 43 15 / 10 40 20 5
QUEMADO......................... 48 25 44 18 / 20 50 20 5
GLENWOOD........................ 51 32 54 22 / 40 40 10 0
CHAMA........................... 38 8 34 9 / 5 20 10 10
LOS ALAMOS...................... 39 23 40 16 / 5 20 30 10
PECOS........................... 43 25 41 17 / 5 20 20 10
CERRO/QUESTA.................... 37 10 37 6 / 5 10 20 10
RED RIVER....................... 39 14 33 8 / 5 10 20 10
ANGEL FIRE...................... 42 10 38 8 / 5 10 20 10
TAOS............................ 40 14 39 9 / 5 10 20 5
MORA............................ 49 22 43 14 / 5 10 20 5
ESPANOLA........................ 43 21 45 16 / 0 10 20 5
SANTA FE........................ 37 24 40 16 / 5 20 30 5
SANTA FE AIRPORT................ 40 24 42 16 / 5 20 30 5
ALBUQUERQUE FOOTHILLS........... 39 27 44 23 / 10 30 40 5
ALBUQUERQUE HEIGHTS............. 42 31 47 24 / 10 20 30 5
ALBUQUERQUE VALLEY.............. 44 27 49 21 / 10 20 30 5
ALBUQUERQUE WEST MESA........... 45 27 48 22 / 10 20 30 5
LOS LUNAS....................... 44 29 50 20 / 10 20 30 5
RIO RANCHO...................... 43 30 47 22 / 10 20 30 5
SOCORRO......................... 48 31 55 24 / 20 20 20 5
SANDIA PARK/CEDAR CREST......... 36 25 42 16 / 10 30 40 10
TIJERAS......................... 38 25 43 20 / 10 20 40 5
MORIARTY/ESTANCIA............... 38 23 43 11 / 10 20 30 10
CLINES CORNERS.................. 37 27 40 16 / 10 20 20 10
GRAN QUIVIRA.................... 43 29 45 21 / 30 30 30 10
CARRIZOZO....................... 47 29 49 24 / 40 30 30 5
RUIDOSO......................... 44 32 48 22 / 60 30 20 5
CAPULIN......................... 46 21 44 14 / 5 5 5 5
RATON........................... 51 25 50 15 / 5 5 5 5
SPRINGER........................ 49 24 51 14 / 0 5 5 5
LAS VEGAS....................... 49 27 46 14 / 5 10 10 5
CLAYTON......................... 53 28 51 20 / 0 5 5 0
ROY............................. 47 26 49 18 / 0 5 5 5
CONCHAS......................... 54 30 56 24 / 0 0 5 0
SANTA ROSA...................... 53 32 54 23 / 10 5 5 0
TUCUMCARI....................... 51 31 56 22 / 5 5 5 0
CLOVIS.......................... 44 27 56 21 / 20 10 5 0
PORTALES........................ 44 30 56 22 / 20 10 5 0
FORT SUMNER..................... 46 30 57 24 / 20 10 5 0
ROSWELL......................... 46 31 63 27 / 50 30 5 0
PICACHO......................... 45 31 57 26 / 60 30 10 5
ELK............................. 47 31 54 25 / 60 30 10 5
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
210 AM EST THU DEC 12 2013
.SYNOPSIS...
LAKE EFFECT SNOW WILL CONTINUE EAST AND SOUTHEAST OF LAKES ONTARIO
AND ERIE...OCCASIONALLY BRINGING SNOW SQUALLS TO THE REGION THROUGH
FRIDAY. A VERY COLD AIR MASS WILL KEEP TEMPERATURES BELOW NORMAL
THE REST OF THIS WEEK. A STORM SYSTEM THIS WEEKEND MAY BRING
ACCUMULATING SNOWFALL TO ALL OF NORTHEAST PENNSYLVANIA AND CENTRAL
NEW YORK.
&&
.NEAR TERM /THROUGH TODAY/...
RADAR SHOWS THE LAKE ONTARIO BAND BEGINNING TO MAKES ITS MOVE TO
THE SOUTH AND EAST AT THIS TIME. STILL HAVE SNOW FALLING IN NW
ONEIDA COUNTY SO OPTED TO KEEP WARNING GOING. NEXT UPDATE PROBABLY
WILL BE ABLE TO DROP IT AS SNOWS SHUD BE TO THE SOUTH IN THE NEXT
FEW HOURS. SHORT RANGE MESOSCALE MODELS INDICATE THAT A FAIRLY
STRG SFC HIGH TRIES TO BUILD IN BEHIND THE DEPARTING SHRT WAVE
THAT WAS MOVING INTO NRN NEW ENGLAND AND SERN CANADA AT THIS
TIME. THE EFFECT OF THIS WAS TO VEER THE LL WINDS TO N OR NERLY UP
TO 925 MB IN NC NY WHICH IN EFFECT SHIFTS THE LES BANDS WELL TO
THE W AND WEAKENS THE ACVTY AS VERY DRY BNDRY LAYER AIR MOVES IN.
DWPTS WERE IN THE SINGLE DIGITS SUGGESTING VERY DRY AIR WHICH WUD
CUT DOWN LES POTENTIAL FOR OVRNGT. THE HRRR...LOCAL WRF...WRF-ARW AND
WRF- NMM AND EVEN THE RAP ALL SUGGEST THIS. HOWEVER...THE VWP FROM
KTYX DOES NOT SHOW THIS LL NERLY FLOW AS IT REMAINS NWRLY. THIS
SUGGESTS THAT THESE MESOSCALE MODELS WERE OVERDOING THIS SFC HIGH
WHICH WAS BUILDING TO OUR NORTH. THE NEW 00Z NAM KEEPS A LL NW FLO
DOWN INTO THE LES ADVY AREA ALL NGT AND HENCE...GIVEN THIS NEW MODEL
DATA...RADAR TRENDS AND THE KTYX VWP I THINK OUR LES ADVY FOR NC
NY STILL LOOKS GOOD. TWEAKED AMNTS A TAD BUT GENERALLY 4 TO 7
INCHES WILL FALL IN MUCH OF THIS AREA OVERNIGHT AND THU AM. THE
FLO ACRS THE ENTIRE AREA GOES W-SWRLY THU DURING THE DAY AND THE
LES WILL RAPIDLY SHIFT BACK N THU.
THE LAKE ERIE BAND HAS NOW WORKED OFF OF LAKE ERIE IN THE NW FLO
PATTERN AND WILL ADVECT SOUTHEASTWARD AND FALL APART AS IT MOVES
INTO NE PA AS PER MODEL GUIDC. THERE WILL BE SUBSC AS WELL BEHIND
THE DEPARTING SHRT WAVE AND THE BAND WILL BECOME MOISTURE STARVED
AS IT WORKS AWAY FROM THE LAKE. HENCE NAM AND OTHER MESO MODELS
LOOK ON TRACK WITH THIS BAND FALLING APART IN NE PA AND THE
CATSKILLS NEXT FEW HOURS.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
315 PM UPDATE...
REINVIGORATED LAKE EFFECT SNOW BAND WILL REDEVELOP EAST OF LAKE
ONTARIO THURSDAY NIGHT INTO FRIDAY. SPECIFICS OF EXACTLY WHERE
THAT BAND SETS UP REMAIN TO BE SEEN...BUT THERE IS A GOOD CHANCE
THAT IT WILL INVOLVE NORTHERN ONEIDA COUNTY. DENDRITIC GROWTH
BEGINS TO SLOWLY RISE IN HEIGHT YET ALSO THICKEN WHILE STILL
HAVING OMEGA EXTEND THROUGH IT EVEN INTO FRIDAY MORNING. THIS
ALONG WITH EXPECTED VERY HIGH SNOW TO LIQUID RATIOS COMPELLED ME
TO HOIST ANOTHER LAKE EFFECT SNOW WATCH FOR NORTHERN ONEIDA
COUNTY. EXTREME NORTHERN ONEIDA COUNTY POTENTIAL FOR MORE THAN 6
INCHES OF SNOW LOOKS PRETTY GOOD...AND INDEED IF THE BAND ENDS UP
SITTING THERE INSTEAD OF JUST NORTH...ACCUMULATIONS COULD BE MUCH
MORE. AS WITH ALL LAKE EFFECT...THE HIGHEST AMOUNTS WILL BE
LOCALIZED WITH ONE SPOT GETTING MANY INCHES AND OTHERS JUST A FEW
MILES AWAY SIGNIFICANTLY LESS. MEANWHILE...LAKE ERIE BAND WILL
AGAIN EXTEND SNOW SHOWERS ACROSS MUCH OF CENTRAL NEW YORK WITH
LIGHT FLUFFY ACCUMULATIONS POSSIBLE.
WAVE ASSOCIATED WITH WARM AIR ADVECTION ALOFT...AND SHEARING LOW
LEVEL FLOW...SHOULD DIMINISH LES INTENSITY DURING THE DAY FRIDAY.
HOWEVER...THE WAVE ITSELF COULD YIELD SOME LIGHT SYNOPTIC SNOW
OUTSIDE OF LES AREAS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
205 AM UPDATE...
CONCENTRATED ON THE WEEKEND STORM FOR THIS PACKAGE. OPTED FOR A
GFS/EURO BLEND WHEN DETERMINING PRECIP TYPE, AND SLIGHTLY
TRUNCATED THE SLEET/MIX LINE SOUTHWARD IN FAVOR OF A LITTLE MORE
SNOW.
MODELS CONTINUE TO SHOW SPLIT ENERGY WITH A NEW ENGLAND COAST
CYCLONE HAVING SOME OF ITS POTENCY ROBBED BY THE GREAT LAKES
WAVE/LOW. THE EFFECT IS TO KEEP THE SYSTEM A BIT DISORGANIZED,
THUS DECREASING MAX QPF POTENTIAL. PROVIDED THE SYSTEM REMAINS
COLD, ADVISORY ACCUMS LOOK LIKE A LOCK.
PREV DISCUSSION...
MAIN ISSUE DURING THE LONG TERM PERIOD CONTINUES TO BE POTENTIAL
FOR WIDESPREAD SNOWS AND EVEN THE POSSIBILITY FOR SOME MIXED
PRECIP ACROSS THE LWR WYOMING VLY AND POCONOS BEGINNING SATURDAY
AND LASTING INTO SATURDAY NIGHT/EARLY SUNDAY. DURING THIS
TIMEFRAME...FCST MODELS CONTINUE TO ADVERTISE A NORTHERN STREAM
WAVE DIVING SOUTH AND EAST ACROSS THE WESTERN GREAT LAKES/UPPER
MIDWEST...WHILE ANOTHER SOUTHERN STREAM WAVE EJECTS FROM THE
SOUTHERN PLAINS INTO THE LOWER MISS RVR VLY. AS BOTH UPPER WAVES
DIG...MODELS AGREE THAT A FRONTAL BOUNDARY STALLED TO OUR SOUTH
WILL BEGIN ADVANCING NORTH ONCE AGAIN AS A CONSOLIDATING 850-MB
LOW BEGINS MOVING NORTHEAST FROM THE MID MISS VLY INTO SOUTHERN
ONTARIO PROVINCE BY 00Z SUNDAY. AHEAD OF THIS FEATURE...EXPECT
DEVELOPING WARM AIR ADVECTION SNOWS AS 850-MB FLOW INCREASES TO
NEAR 30 KTS AND ISENTROPIC ASCENT INCREASES ALONG THE 285 AND 290K
THETA SURFACES. FROM THIS VANTAGE POINT...WARM AIR ADVECTION SNOWS
LOOK TO CONTINUE THROUGH A GOOD PART OF THE DAY AS FIRST THE
850-MB LOW CENTER TRACKS NORTH AND EAST OF OUR FCST AREA...AND THE
SOUTHERN STREAM SFC REFLECTION MOVES OFF THE SOUTHEASTERN VIRGINA
COAST BY 00Z SUNDAY. UNDER THIS SCENARIO...MUCH OF THE FCST AREA
WILL REMAIN IN THE NORTHWEST QUADRANT OF THE PRIMARY SFC FEATURE
THUS ENSURING LOW-LEVEL COLD AIR WILL REMAIN IN PLACE THROUGH MUCH
OF THE EVENT. THE ONLY EXCEPTION AS OF RIGHT NOW APPEARS TO BE ACROSS
THE LWR WYOMING VLY AND POCONOS SATURDAY NGT WHERE SOME WARM AIR
MAY TEMPORARILY ADVANCE INTO NORTHEAST PA AS ENERGY FROM THE
NORTHERN STREAM SFC LOW TRANSFERS TO THE MAIN LOW OFF THE
ATLANTIC SEABOARD. SNOWS EXPECTED TO CONTINUE THROUGH MUCH OF THE
OVERNIGHT AS MOISTURE WRAPS IN FROM THE MAIN LOW OFF THE COAST
AND ADDITIONAL FORCING FOR ASCENT BECOMING MORE APPARENT AS PVA
INCREASES IN ADVANCE OF AFOREMENTIONED NORTHERN STREAM WAVE
APPROACHING FROM THE CENTRAL LAKES AND SOUTHERN ONTARIO. AS A
RESULT...CONFIDENCE IS INCREASING THAT SEVERAL INCHES OF SYNOPTIC
SNOW CAN BE EXPECTED ACROSS THE AREA THROUGH THE WEEKEND. FOR
NOW...WILL HIGHLIGHT CONCERNS ON THE HWO PRODUCT UNTIL FCST
DETAILS BECOME MORE CERTAIN PENDING ADDITIONAL MODEL GUIDANCE.
BEYOND THIS...BROAD NORTHWEST FLOW TO RESULT IN REDEVELOPING LAKE
SNOWS EAST AND SOUTHEAST OF BOTH LAKES EARLY INTO NEXT WEEK...WITH
ADDITIONAL SYNOPTIC SNOWS POSSIBLE MONDAY NIGHT/EARLY TUESDAY AS
ELONGATED WARM FRONT ADVANCES NORTH ACROSS THE AREA. TEMPS THROUGH
THE PERIOD LOOK TO HOVER SLIGHTLY BELOW NORMAL AS COOL NORTHWEST
FLOW REMAINS IN PLACE.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
LAKE BAND HAS SHIFTED WITH A MORE NORTHWESTERLY WIND COMPONENT,
EXITING RME AND ENTERING SYR. THE LAKE SNOW BAND WILL RAPIDLY
WEAKEN BETWEEN 8Z AND 10Z, AS LOW AMPLITUDE WIND FLOW WILL
DIMINISH THE INLAND BAND EXTENT. AS A RESULT, WE EXPECT IFR
CONDITIONS TO PERSIST AT SYR THROUGH THE NEXT 3 TO 4 HOURS, WITH
TEMPO IFR POSSIBLE THROUGH 10Z.
AFTER 10Z THE BAND SHOULD HAVE EXITED THE SYR TERMINAL COMPLETELY.
THE LAKE BAND WILL REFORM DURING THE AFTERNOON. IT APPEARS THE
BAND WILL AFFECT FAR NORTHERN ONEIDA COUNTY AND OSWEGO COUNTY.
HOWEVER THE PERIPHERY MAY BRUSH RME. THE BEST CHANCE FOR MVFR OR
IFR SNOW SHOWERS AT RME WILL BE BETWEEN 16Z AND 20Z.
LAKE ERIE SNOW SHOWERS COULD POTENTIALLY AFFECT THE BGM, ELM, OR
ITH TERMINALS AT ANY POINT THIS AFTERNOON. THESE SHOULD BE BRIEF
ENOUGH TO PRECLUDE INCLUDING IN THE FORECAST. FUTURE SHIFTS CAN
HANDLE ISOLATED LAKE ACTIVITY WITH AMD UPDATES.
OUTLOOK...
FRI...MAINLY VFR...HOWEVER RESTRICTIONS POSSIBLE IN LAKE EFFECT
SNOW AT KRME.
SAT/SUN...RESTRICTIONS LIKELY REGION-WIDE IN SNOW AS STORM SYSTEM
MOVES THROUGH THE AREA.
SUN NGT/MON...RESTRICTIONS POSSIBLE FROM LAKE EFFECT SNOW SHOWERS
ESPECIALLY KSYR-KRME.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 11 AM EST THIS MORNING FOR
NYZ017-018-036-037-044>046.
LAKE EFFECT SNOW WATCH FROM NOON EST TODAY THROUGH FRIDAY
AFTERNOON FOR NYZ009.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...MDP
LONG TERM...CMG/DJP
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1227 AM EST THU DEC 12 2013
.SYNOPSIS...
LAKE EFFECT SNOW WILL CONTINUE EAST AND SOUTHEAST OF LAKES ONTARIO
AND ERIE...OCCASIONALLY BRINGING SNOW SQUALLS TO THE REGION THROUGH
FRIDAY. A VERY COLD AIR MASS WILL KEEP TEMPERATURES BELOW NORMAL
THE REST OF THIS WEEK. A STORM SYSTEM THIS WEEKEND MAY BRING
ACCUMULATING SNOWFALL TO ALL OF NORTHEAST PENNSYLVANIA AND CENTRAL
NEW YORK.
&&
.NEAR TERM /THROUGH TODAY/...
RADAR SHOWS THE LAKE ONTARIO BAND BEGINNING TO MAKES ITS MOVE TO
THE SOUTH AND EAST AT THIS TIME. STILL HAVE SNOW FALLING IN NW
ONEIDA COUNTY SO OPTED TO KEEP WARNING GOING. NEXT UPDATE PROBABLY
WILL BE ABLE TO DROP IT AS SNOWS SHUD BE TO THE SOUTH IN THE NEXT
FEW HOURS. SHORT RANGE MESOSCALE MODELS INDICATE THAT A FAIRLY
STRG SFC HIGH TRIES TO BUILD IN BEHIND THE DEPARTING SHRT WAVE
THAT WAS MOVING INTO NRN NEW ENGLAND AND SERN CANADA AT THIS
TIME. THE EFFECT OF THIS WAS TO VEER THE LL WINDS TO N OR NERLY UP
TO 925 MB IN NC NY WHICH IN EFFECT SHIFTS THE LES BANDS WELL TO
THE W AND WEAKENS THE ACVTY AS VERY DRY BNDRY LAYER AIR MOVES IN.
DWPTS WERE IN THE SINGLE DIGITS SUGGESTING VERY DRY AIR WHICH WUD
CUT DOWN LES POTENTIAL FOR OVRNGT. THE HRRR...LOCAL WRF...WRF-ARW AND
WRF- NMM AND EVEN THE RAP ALL SUGGEST THIS. HOWEVER...THE VWP FROM
KTYX DOES NOT SHOW THIS LL NERLY FLOW AS IT REMAINS NWRLY. THIS
SUGGESTS THAT THESE MESOSCALE MODELS WERE OVERDOING THIS SFC HIGH
WHICH WAS BUILDING TO OUR NORTH. THE NEW 00Z NAM KEEPS A LL NW FLO
DOWN INTO THE LES ADVY AREA ALL NGT AND HENCE...GIVEN THIS NEW MODEL
DATA...RADAR TRENDS AND THE KTYX VWP I THINK OUR LES ADVY FOR NC
NY STILL LOOKS GOOD. TWEAKED AMNTS A TAD BUT GENERALLY 4 TO 7
INCHES WILL FALL IN MUCH OF THIS AREA OVERNIGHT AND THU AM. THE
FLO ACRS THE ENTIRE AREA GOES W-SWRLY THU DURING THE DAY AND THE
LES WILL RAPIDLY SHIFT BACK N THU.
THE LAKE ERIE BAND HAS NOW WORKED OFF OF LAKE ERIE IN THE NW FLO
PATTERN AND WILL ADVECT SOUTHEASTWARD AND FALL APART AS IT MOVES
INTO NE PA AS PER MODEL GUIDC. THERE WILL BE SUBSC AS WELL BEHIND
THE DEPARTING SHRT WAVE AND THE BAND WILL BECOME MOISTURE STARVED
AS IT WORKS AWAY FROM THE LAKE. HENCE NAM AND OTHER MESO MODELS
LOOK ON TRACK WITH THIS BAND FALLING APART IN NE PA AND THE
CATSKILLS NEXT FEW HOURS.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
315 PM UPDATE...
REINVIGORATED LAKE EFFECT SNOW BAND WILL REDEVELOP EAST OF LAKE
ONTARIO THURSDAY NIGHT INTO FRIDAY. SPECIFICS OF EXACTLY WHERE
THAT BAND SETS UP REMAIN TO BE SEEN...BUT THERE IS A GOOD CHANCE
THAT IT WILL INVOLVE NORTHERN ONEIDA COUNTY. DENDRITIC GROWTH
BEGINS TO SLOWLY RISE IN HEIGHT YET ALSO THICKEN WHILE STILL
HAVING OMEGA EXTEND THROUGH IT EVEN INTO FRIDAY MORNING. THIS
ALONG WITH EXPECTED VERY HIGH SNOW TO LIQUID RATIOS COMPELLED ME
TO HOIST ANOTHER LAKE EFFECT SNOW WATCH FOR NORTHERN ONEIDA
COUNTY. EXTREME NORTHERN ONEIDA COUNTY POTENTIAL FOR MORE THAN 6
INCHES OF SNOW LOOKS PRETTY GOOD...AND INDEED IF THE BAND ENDS UP
SITTING THERE INSTEAD OF JUST NORTH...ACCUMULATIONS COULD BE MUCH
MORE. AS WITH ALL LAKE EFFECT...THE HIGHEST AMOUNTS WILL BE
LOCALIZED WITH ONE SPOT GETTING MANY INCHES AND OTHERS JUST A FEW
MILES AWAY SIGNIFICANTLY LESS. MEANWHILE...LAKE ERIE BAND WILL
AGAIN EXTEND SNOW SHOWERS ACROSS MUCH OF CENTRAL NEW YORK WITH
LIGHT FLUFFY ACCUMULATIONS POSSIBLE.
WAVE ASSOCIATED WITH WARM AIR ADVECTION ALOFT...AND SHEARING LOW
LEVEL FLOW...SHOULD DIMINISH LES INTENSITY DURING THE DAY FRIDAY.
HOWEVER...THE WAVE ITSELF COULD YIELD SOME LIGHT SYNOPTIC SNOW
OUTSIDE OF LES AREAS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MAIN ISSUE DURING THE LONG TERM PERIOD CONTINUES TO BE POTENTIAL
FOR WIDESPREAD SNOWS AND EVEN THE POSSIBILITY FOR SOME MIXED
PRECIP ACROSS THE LWR WYOMING VLY AND POCONOS BEGINNING SATURDAY
AND LASTING INTO SATURDAY NIGHT/EARLY SUNDAY. DURING THIS
TIMEFRAME...FCST MODELS CONTINUE TO ADVERTISE A NORTHERN STREAM
WAVE DIVING SOUTH AND EAST ACROSS THE WESTERN GREAT LAKES/UPPER
MIDWEST...WHILE ANOTHER SOUTHERN STREAM WAVE EJECTS FROM THE
SOUTHERN PLAINS INTO THE LOWER MISS RVR VLY. AS BOTH UPPER WAVES
DIG...MODELS AGREE THAT A FRONTAL BOUNDARY STALLED TO OUR SOUTH
WILL BEGIN ADVANCING NORTH ONCE AGAIN AS A CONSOLIDATING 850-MB
LOW BEGINS MOVING NORTHEAST FROM THE MID MISS VLY INTO SOUTHERN
ONTARIO PROVINCE BY 00Z SUNDAY. AHEAD OF THIS FEATURE...EXPECT
DEVELOPING WARM AIR ADVECTION SNOWS AS 850-MB FLOW INCREASES TO
NEAR 30 KTS AND ISENTROPIC ASCENT INCREASES ALONG THE 285 AND 290K
THETA SURFACES. FROM THIS VANTAGE POINT...WARM AIR ADVECTION SNOWS
LOOK TO CONTINUE THROUGH A GOOD PART OF THE DAY AS FIRST THE
850-MB LOW CENTER TRACKS NORTH AND EAST OF OUR FCST AREA...AND THE
SOUTHERN STREAM SFC REFLECTION MOVES OFF THE SOUTHEASTERN VIRGINA
COAST BY 00Z SUNDAY. UNDER THIS SCENARIO...MUCH OF THE FCST AREA
WILL REMAIN IN THE NORTHWEST QUADRANT OF THE PRIMARY SFC FEATURE
THUS ENSURING LOW-LEVEL COLD AIR WILL REMAIN IN PLACE THROUGH MUCH
OF THE EVENT. THE ONLY EXCEPTION AS OF RIGHT NOW APPEARS TO BE ACROSS
THE LWR WYOMING VLY AND POCONOS SATURDAY NGT WHERE SOME WARM AIR
MAY TEMPORARILY ADVANCE INTO NORTHEAST PA AS ENERGY FROM THE
NORTHERN STREAM SFC LOW TRANSFERS TO THE MAIN LOW OFF THE
ATLANTIC SEABOARD. SNOWS EXPECTED TO CONTINUE THROUGH MUCH OF THE
OVERNIGHT AS MOISTURE WRAPS IN FROM THE MAIN LOW OFF THE COAST
AND ADDITIONAL FORCING FOR ASCENT BECOMING MORE APPARENT AS PVA
INCREASES IN ADVANCE OF AFOREMENTIONED NORTHERN STREAM WAVE
APPROACHING FROM THE CENTRAL LAKES AND SOUTHERN ONTARIO. AS A
RESULT...CONFIDENCE IS INCREASING THAT SEVERAL INCHES OF SYNOPTIC
SNOW CAN BE EXPECTED ACROSS THE AREA THROUGH THE WEEKEND. FOR
NOW...WILL HIGHLIGHT CONCERNS ON THE HWO PRODUCT UNTIL FCST
DETAILS BECOME MORE CERTAIN PENDING ADDITIONAL MODEL GUIDANCE.
BEYOND THIS...BROAD NORTHWEST FLOW TO RESULT IN REDEVELOPING LAKE
SNOWS EAST AND SOUTHEAST OF BOTH LAKES EARLY INTO NEXT WEEK...WITH
ADDITIONAL SYNOPTIC SNOWS POSSIBLE MONDAY NIGHT/EARLY TUESDAY AS
ELONGATED WARM FRONT ADVANCES NORTH ACROSS THE AREA. TEMPS THROUGH
THE PERIOD LOOK TO HOVER SLIGHTLY BELOW NORMAL AS COOL NORTHWEST
FLOW REMAINS IN PLACE.
&&
.AVIATION /05Z THURSDAY THROUGH MONDAY/...
LAKE BAND HAS SHIFTED WITH A MORE NORTHWESTERLY WIND COMPONENT,
EXITING RME AND ENTERING SYR. THE LAKE SNOW BAND WILL RAPIDLY
WEAKEN BETWEEN 8Z AND 10Z, AS LOW AMPLITUDE WIND FLOW WILL
DIMINISH THE INLAND BAND EXTENT. AS A RESULT, WE EXPECT IFR
CONDITIONS TO PERSIST AT SYR THROUGH THE NEXT 3 TO 4 HOURS, WITH
TEMPO IFR POSSIBLE THROUGH 10Z.
AFTER 10Z THE BAND SHOULD HAVE EXITED THE SYR TERMINAL COMPLETELY.
THE LAKE BAND WILL REFORM DURING THE AFTERNOON. IT APPEARS THE
BAND WILL AFFECT FAR NORTHERN ONEIDA COUNTY AND OSWEGO COUNTY.
HOWEVER THE PERIPHERY MAY BRUSH RME. THE BEST CHANCE FOR MVFR OR
IFR SNOW SHOWERS AT RME WILL BE BETWEEN 16Z AND 20Z.
LAKE ERIE SNOW SHOWERS COULD POTENTIALLY AFFECT THE BGM, ELM, OR
ITH TERMINALS AT ANY POINT THIS AFTERNOON. THESE SHOULD BE BRIEF
ENOUGH TO PRECLUDE INCLUDING IN THE FORECAST. FUTURE SHIFTS CAN
HANDLE ISOLATED LAKE ACTIVITY WITH AMD UPDATES.
OUTLOOK...
FRI...MAINLY VFR...HOWEVER RESTRICTIONS POSSIBLE IN LAKE EFFECT
SNOW AT KRME.
SAT/SUN...RESTRICTIONS LIKELY REGION-WIDE IN SNOW AS STORM SYSTEM
MOVES THROUGH THE AREA.
SUN NGT/MON...RESTRICTIONS POSSIBLE FROM LAKE EFFECT SNOW SHOWERS
ESPECIALLY KSYR-KRME.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 11 AM EST THIS MORNING FOR
NYZ017-018-036-037-044>046.
LAKE EFFECT SNOW WATCH FROM NOON EST TODAY THROUGH FRIDAY
AFTERNOON FOR NYZ009.
LAKE EFFECT SNOW WARNING UNTIL 6 AM EST EARLY THIS MORNING FOR
NYZ009.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...MDP
LONG TERM...CMG
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
330 PM CST THU DEC 12 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 330 PM CST THU DEC 12 2013
MAIN FORECAST CONCERNS IN THE SHORT TERM WILL BE EXTENT OF LIGHT
SNOW WITH PASSING UPPER WAVES AND TEMP TRENDS...WITH COLD AIR
REMAINING FIRMLY ENTRENCHED.
A NARROW BAND OF LIGHT SNOW HAS PROGRESSED FROM THE NORTHERN
VALLEY SOUTHEASTWARD INTO NW MINNESOTA THIS AFTERNOON. THIS WILL
CONTINUE TO SHIFT SOUTHEASTWARD THROUGH THE REST OF THE AFTERNOON.
ANOTHER AREA OF LIGHT SNOW WILL SHIFT INTO THE DEVILS LAKE BASIN
THIS EVENING AND SOUTHEASTWARD OVERNIGHT...IN ASSOCIATION WITH AN
AREA OF MID-LEVEL FRONTOGENESIS AND SYNOPTIC FORCING IN THE RIGHT
ENTRANCE REGION OF A BROAD UPPER JET. AS THE FORCING GRADUALLY
WEAKENS...A DECREASING TREND IN THE SNOWFALL IS EXPECTED WITH TIME
AS THE SNOW SHIFTS SOUTHWARD. RIGHT NOW THE BEST CHANCE FOR 1 TO 3
INCHES OF ACCUMULATION LOOKS TO BE FROM THE DEVILS LAKE AREA INTO
PARTS OF THE NORTHERN AND CENTRAL VALLEY TONIGHT INTO FRIDAY.
TEMPS TONIGHT MAY BE TRICKY. ALTHOUGH LOW-LEVEL COLD ADVECTION
WILL CONTINUE THROUGH THE NIGHT...HOW MUCH TEMPS FALL WILL DEPEND
ON CLOUD COVERAGE. THE RAP BRINGS SOME LOW-LEVEL DRYING INTO PARTS
OF NORTHWEST MINNESOTA OVERNIGHT. TEMPS COULD DROP PRETTY QUICKLY
IF ANY CLEARING DOES OCCUR...AND THUS HAVE THE LOWEST TEMPS IN
THIS AREA OF NW MINNESOTA. HIGHS ON FRIDAY LIKELY WILL BE COLDEST
NORTH...WITH TEMPS REMAINING BELOW ZERO...AND SINGLE DIGITS ABOVE
ZERO FARTHER SOUTH.
AS WINDS ARE EXPECTED TO STAY UP AROUND 10 KTS OVERNIGHT...WILL
ALSO ISSUE A WIND CHILL ADVISORY FOR MUCH OF NE ND EASTWARD INTO
NW MN FROM 06Z TONIGHT THROUGH 03Z SATURDAY. WITH WINDS BRISK FROM
THE NORTHEAST ON FRIDAY AHEAD OF THE SFC HIGH...HELD ONTO THE
ADVISORY UNTIL FRIDAY EVENING...ALTHOUGH WIND CHILLS MAY RISE ABOVE
CRITERIA FOR A BIT DURING THE DAY. AS THE SFC RIDGE AXIS
APPROACHES FRIDAY NIGHT...WINDS MAY GO LIGHT...ALLOWING FOR WIND
CHILLS TO RISE ABOVE ADVISORY THRESHOLD. THIS WILL BE MONITORED
DURING FUTURE SHIFTS THOUGH.
A SERIES OF UPPER IMPULSES EMBEDDED IN NORTHWEST FLOW ALOFT WILL
CONTINUE TO AFFECT THE AREA FRIDAY NIGHT INTO SATURDAY...BRINGING
CONTINUED CHANCES FOR LIGHT SNOW. ALTHOUGH MODEL QPF IS LOW...WITH
HIGH SNOW RATIOS AND MODEL SOUNDINGS INDICATING A FAIRLY DEEP
SATURATED LAYER...A FLUFFY INCH OR TWO OF SNOW IS
POSSIBLE...DEPENDING ON THE EXACT TRACK OF THE IMPULSES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 330 PM CST THU DEC 12 2013
TEMPS ON SATURDAY WILL RISE INTO THE SINGLE DIGITS EITHER SIDE OF
ZERO WITH LIGHT SNOW REMAINING POSSIBLE AS UPPER LEVEL ENERGY
CASCADES THROUGH THE FLOW. A SFC RIDGE WILL SPREAD OVER THE AREA
ON SATURDAY NIGHT. THE MAIN QUESTION WILL BE TEMPS...WHICH WILL BE
DEPENDENT ON CLOUD COVER. THUS...TEMPS COULD BE A BIT COLDER IF
SKIES DO CLEAR.
ANOTHER ROUND OF LIGHT SNOW IS POSSIBLE SUNDAY AS WARM AIR ADVECTION
DEVELOPS AND THE LOW-LEVEL BAROCLINIC ZONE APPROACHES FROM THE WEST
AHEAD OF THE NEXT UPPER WAVE. HOWEVER...TEMPS WILL REMAIN WELL
BELOW NORMAL.
FOR THE SUNDAY NIGHT THROUGH THURSDAY PERIOD...12Z ECMWF/GFS/GEM SO
ENOUGH DISAGREEMENT IN TIMING AND LOCATION OF SEVERAL 500 MB SHORT
WAVES/SURFACE LOW PRESSURE SYSTEMS TO KEEP CONFIDENCE IN FCST A BIT
LOWER THAN NORMAL. IDEA IS FOR ONE SHORT WAVE MONDAY TO EXIT
FOLLOWED BY SOME COLDER AIR MON NIGHT-TUE THEN THE NEXT ONE DUE WED
NIGHT-THU TIME FRAME. EXACT PLACEMENT OF LOWS WILL MEAN POTENTIAL
TEMP DIFFERENCES WITH OVERALL 12Z EURO AND GEM A BIT WARMER THAN 12Z
GFS ESP FOR MID WEEK SYSTEM. WITH THE DIFFERENCES STUCK WITH ALL
BLEND GUIDANCE. THERAFTER AND BEYOND THIS PERIOD IS WHEN THE NEXT
ARCTIC OUBREAK WILL OCCUR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1245 PM CST THU DEC 12 2013
EXPECT MVFR-VFR CONDITIONS THRU THE PERIOD. MVFR CIGS INTO DVL
REGION AND EXPECT THE VFR CIGS ELSEWHERE TO GRADUALLY TURN MORE
MVFR OVERNIGHT INTO FRIDAY AS COLD FRONT SINKS SOUTH. SOME VERY
LIGHT SNOW WITH THIS FEATURE NRN VALLEY INTO FAR NW MN BUT VSBY
P6SM. A BIT BETTER CHANCE FOR SOME 3-5SM VSBYS IN -SN LATE TONIGHT
INTO FRIDAY WITH NEXT WAVE. WINDS WILL TURN TO A MORE NORTH-
NORTHEAST DIRECTION AT 10 TO 18 KTS TONIGHT AND FRIDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 PM CST FRIDAY FOR
NDZ006>008-014>016-024-026>030-054.
MN...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 PM CST FRIDAY FOR
MNZ001-002-004>009-013>017-022-023.
&&
$$
SHORT TERM...MAKOWSKI
LONG TERM...RIDDLE
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
112 PM CST THU DEC 12 2013
.UPDATE...
ISSUED AT 102 PM CST THU DEC 12 2013
QUIET WEATHER ACROSS THE NORTHERN PLAINS TODAY. DIM SUNSHINE
PEEKING THROUGH THE SOUTH. CLOUDY NORTH. VERY LITTLE SNOW FALLING
NORTH SO WILL JUST GO FLURRIES FOR THE AFTERNOON. TEMP SENSOR AT
BAKER MONTANA MALFUNCTIONING SO REMOVED FROM THE GRIDDED DATABASE
AS THIS WAS INFLATING THE CURRENT TEMPERATURES ACROSS THE FAR
SOUTHWEST.
UPDATE ISSUED AT 934 AM CST THU DEC 12 2013
AT 9 AM CST...A WARM FRONTAL BOUNDARY ACROSS NORTHEAST MONTANA
AND SOUTHWEST NORTH DAKOTA WILL BE THE FOCUS FOR LIGHT SNOW ACROSS
NORTH CENTRAL NORTH DAKOTA. THE CHANCE OF SNOW WILL INCREASE
ACROSS THE NORTH CENTRAL TONIGHT AND FRIDAY. FOR TODAY...EXPECT
LITTLE SNOW ACROSS THE SOUTH. KEPT 20-30 POPS ACROSS THE NORTH.
TEMPERATURES ACROSS THE REGION WILL REMAIN COOL NORTHEAST. SHOULD
GET CLOSE TO THE FREEZING MARK SOUTHWEST.
UPDATE ISSUED AT 643 AM CST THU DEC 12 2013
UPDATE FOR POPS AND TEMPERATURE TRENDS. BASED ON 11Z RAP GUIDANCE
AND RADAR/OBS TRENDS...HAVE EXPANDED AREA OF LIGHT SNOW SHOWERS TO
INCLUDE MOST OF THE FORECAST AREA THIS MORNING. THE FOCUS OF THE
SNOW LATER THIS AFTERNOON WILL BE THE FAR NORTH. HOWEVER...MOST
ACCUMULATING SNOW WILL OCCUR AFTER 00Z THIS EVENING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CST THU DEC 12 2013
THE HIGHLIGHT OF THE SHORT TERM IS A BREAK FROM THE ARCTIC
AIR...ESPECIALLY SOUTHWEST AND SOUTH CENTRAL TODAY...FOLLOWED BY
ACCUMULATING SNOW TONIGHT NORTH CENTRAL.
CONTINUED POPS THROUGH 15 UTC ACROSS THE NORTHWEST BASED UPON
LATEST RADAR TRENDS THROUGH 0945 UTC AND THE 08 UTC RAP WHICH IS THE
JUST ABOUT THE ONLY DETERMINISTIC MODEL CAPTURING THE LIGHT SNOW
PROPAGATING IN FROM NORTHEAST MONTANA AND SOUTHEAST SASKATCHEWAN
THIS MORNING.
A QUASI-STATIONARY FRONT ACROSS NORTHWEST THROUGH SOUTHEAST NORTH
DAKOTA THIS MORNING WILL SLOWLY PROPAGATE SOUTHWEST THROUGH THE
DAY AS A COLD FRONT. ON THE WARM SIDE OF THIS BOUNDARY WIDESPREAD
HIGHS IN THE 20S...AND PERHAPS A FEW LOWER 30S ACROSS THE FAR
SOUTHWEST ARE EXPECTED. IN CONTRAST...HIGHS IN THE SINGLE DIGITS
ARE FORECAST ACROSS THE TURTLE MOUNTAINS...WHICH IS IN LINE WITH
THE 00 UTC GUIDANCE CONSENSUS. AS THE LOW LEVEL BAROCLINIC ZONE
STRENGTHENS LATE THIS AFTERNOON AND INTO THE EVENING AS THE
SOUTHERN PERIPHERY OF ARCTIC HIGH PRESSURE BUILDS INTO NORTHERN
NORTH DAKOTA...A BAND OF LIGHT TO MODERATE SNOW IS EXPECTED TO
DEVELOP ACROSS NORTH CENTRAL AND NORTHEAST NORTH DAKOTA AS
FRONTOGENETICAL FORCING INCREASES. ONE TO THREE INCHES OF SNOW IS
EXPECTED FOR THE US HIGHWAY 2 CORRIDOR ACROSS THE NORTH CENTRAL.
AT THIS TIME...WILL HIGHLIGHT THE EVENT WITH AN SPS...ALSO
MENTIONING WIND CHILLS TO 25 BELOW AS ARCTIC AIR BUILDS SOUTH
COUPLED WITH EASTERLY WINDS OF 10-15 KTS WITH THE TIGHT PRESSURE
GRADIENT ON THE SOUTHERN PERIPHERY OF THE SURFACE HIGH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 327 AM CST THU DEC 12 2013
THE MAIN FORECAST ISSUE IS TIMING AND COVERAGE OF SEVERAL LIGHT
SNOW EVENTS THROUGH THE PERIOD.
ON FRIDAY...ANOTHER SURGE OF ARCTIC AIR WILL SPREAD SOUTH ACROSS
THE STATE. LIGHT SNOW WILL CONTINUE FRIDAY...WITH ADDITIONAL
ACCUMULATION FOCUSED ON THE NORTHERN COUNTIES. 1 TO 2 MORE INCHES
WILL BE POSSIBLE THROUGH FRIDAY NIGHT...WITH GENERALLY A LIGHT
DUSTING POSSIBLE IN CENTRAL AND SOUTHERN NORTH DAKOTA. ANOTHER
WEAK SHORT WAVE MAY SUPPORT LIGHT ACCUMULATIONS AGAIN SATURDAY
NIGHT. WIND CHILLS AROUND 25 BELOW ZERO ARE POSSIBLE FRIDAY NIGHT
AND SATURDAY NIGHT ACROSS THE NORTH. LOOKING AHEAD...THERE IS SOME
UNCERTAINTY AS TO HOW FAR EAST THE UPPER RIDGE AND MILDER AIR WILL
PUSH. THE SOUTHWEST PART OF THE STATE...AT THE LEAST...SHOULD WARM
INTO THE 20S AND EVEN LOWER 30S FROM SUNDAY THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 102 PM CST THU DEC 12 2013
VFR ACROSS THE REGION AS A WEAK WARM FRONT IN EASTERN MONTANA NOT
PRODUCING MUCH WEATHER AT THIS TIME. EXPECT VFR ACROSS THE REGION
INTO THIS EVENING. AT THIS TIME EXPECT KMOT TO BE IMPACTED BY MVFR
CONDITIONS THIS EVENING AFTER 00Z. MAY PUSH THIS BACK TO ALMOST
06Z TONIGHT AS AM WAITING FOR UPPER LEVEL DISTURBANCE TO MOVE
ACROSS THE AREA. CONDITIONS DETERIORATING TO IFR KMOT AFTER 12Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
951 AM CST THU DEC 12 2013
.UPDATE...
ISSUED AT 934 AM CST THU DEC 12 2013
AT 9 AM CST...A WARM FRONTAL BOUNDARY ACROSS NORTHEAST MONTANA
AND SOUTHWEST NORTH DAKOTA WILL BE THE FOCUS FOR LIGHT SNOW ACROSS
NORTH CENTRAL NORTH DAKOTA. THE CHANCE OF SNOW WILL INCREASE
ACROSS THE NORTH CENTRAL TONIGHT AND FRIDAY. FOR TODAY...EXPECT
LITTLE SNOW ACROSS THE SOUTH. KEPT 20-30 POPS ACROSS THE NORTH.
TEMPERATURES ACROSS THE REGION WILL REMAIN COOL NORTHEAST. SHOULD
GET CLOSE TO THE FREEZING MARK SOUTHWEST.
UPDATE ISSUED AT 643 AM CST THU DEC 12 2013
UPDATE FOR POPS AND TEMPERATURE TRENDS. BASED ON 11Z RAP GUIDANCE
AND RADAR/OBS TRENDS...HAVE EXPANDED AREA OF LIGHT SNOW SHOWERS TO
INCLUDE MOST OF THE FORECAST AREA THIS MORNING. THE FOCUS OF THE
SNOW LATER THIS AFTERNOON WILL BE THE FAR NORTH. HOWEVER...MOST
ACCUMULATING SNOW WILL OCCUR AFTER 00Z THIS EVENING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CST THU DEC 12 2013
THE HIGHLIGHT OF THE SHORT TERM IS A BREAK FROM THE ARCTIC
AIR...ESPECIALLY SOUTHWEST AND SOUTH CENTRAL TODAY...FOLLOWED BY
ACCUMULATING SNOW TONIGHT NORTH CENTRAL.
CONTINUED POPS THROUGH 15 UTC ACROSS THE NORTHWEST BASED UPON
LATEST RADAR TRENDS THROUGH 0945 UTC AND THE 08 UTC RAP WHICH IS THE
JUST ABOUT THE ONLY DETERMINISTIC MODEL CAPTURING THE LIGHT SNOW
PROPAGATING IN FROM NORTHEAST MONTANA AND SOUTHEAST SASKATCHEWAN
THIS MORNING.
A QUASI-STATIONARY FRONT ACROSS NORTHWEST THROUGH SOUTHEAST NORTH
DAKOTA THIS MORNING WILL SLOWLY PROPAGATE SOUTHWEST THROUGH THE
DAY AS A COLD FRONT. ON THE WARM SIDE OF THIS BOUNDARY WIDESPREAD
HIGHS IN THE 20S...AND PERHAPS A FEW LOWER 30S ACROSS THE FAR
SOUTHWEST ARE EXPECTED. IN CONTRAST...HIGHS IN THE SINGLE DIGITS
ARE FORECAST ACROSS THE TURTLE MOUNTAINS...WHICH IS IN LINE WITH
THE 00 UTC GUIDANCE CONSENSUS. AS THE LOW LEVEL BAROCLINIC ZONE
STRENGTHENS LATE THIS AFTERNOON AND INTO THE EVENING AS THE
SOUTHERN PERIPHERY OF ARCTIC HIGH PRESSURE BUILDS INTO NORTHERN
NORTH DAKOTA...A BAND OF LIGHT TO MODERATE SNOW IS EXPECTED TO
DEVELOP ACROSS NORTH CENTRAL AND NORTHEAST NORTH DAKOTA AS
FRONTOGENETICAL FORCING INCREASES. ONE TO THREE INCHES OF SNOW IS
EXPECTED FOR THE US HIGHWAY 2 CORRIDOR ACROSS THE NORTH CENTRAL.
AT THIS TIME...WILL HIGHLIGHT THE EVENT WITH AN SPS...ALSO
MENTIONING WIND CHILLS TO 25 BELOW AS ARCTIC AIR BUILDS SOUTH
COUPLED WITH EASTERLY WINDS OF 10-15 KTS WITH THE TIGHT PRESSURE
GRADIENT ON THE SOUTHERN PERIPHERY OF THE SURFACE HIGH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 327 AM CST THU DEC 12 2013
THE MAIN FORECAST ISSUE IS TIMING AND COVERAGE OF SEVERAL LIGHT
SNOW EVENTS THROUGH THE PERIOD.
ON FRIDAY...ANOTHER SURGE OF ARCTIC AIR WILL SPREAD SOUTH ACROSS
THE STATE. LIGHT SNOW WILL CONTINUE FRIDAY...WITH ADDITIONAL
ACCUMULATION FOCUSED ON THE NORTHERN COUNTIES. 1 TO 2 MORE INCHES
WILL BE POSSIBLE THROUGH FRIDAY NIGHT...WITH GENERALLY A LIGHT
DUSTING POSSIBLE IN CENTRAL AND SOUTHERN NORTH DAKOTA. ANOTHER
WEAK SHORT WAVE MAY SUPPORT LIGHT ACCUMULATIONS AGAIN SATURDAY
NIGHT. WIND CHILLS AROUND 25 BELOW ZERO ARE POSSIBLE FRIDAY NIGHT
AND SATURDAY NIGHT ACROSS THE NORTH. LOOKING AHEAD...THERE IS SOME
UNCERTAINTY AS TO HOW FAR EAST THE UPPER RIDGE AND MILDER AIR WILL
PUSH. THE SOUTHWEST PART OF THE STATE...AT THE LEAST...SHOULD WARM
INTO THE 20S AND EVEN LOWER 30S FROM SUNDAY THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 934
AM CST THU DEC 12 2013
AT 9 AM CST...A WARM FRONT EXTENDED ACROSS SOUTHWEST NORTH
DAKOTA. VFR CONDITIONS PREVAILED ACROSS THE SOUTH...FROM KDIK-KBIS-
KJMS. KISN-KMOT WILL BE GENERALLY BE VFR...BECOMING MVFR WITH
LIGHT SNOW AFTER 20Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
647 AM CST THU DEC 12 2013
.UPDATE...
ISSUED AT 643 AM CST THU DEC 12 2013
UPDATE FOR POPS AND TEMPERATURE TRENDS. BASED ON 11Z RAP GUIDANCE
AND RADAR/OBS TRENDS...HAVE EXPANDED AREA OF LIGHT SNOW SHOWERS TO
INCLUDE MOST OF THE FORECAST AREA THIS MORNING. THE FOCUS OF THE
SNOW LATER THIS AFTERNOON WILL BE THE FAR NORTH. HOWEVER...MOST
ACCUMULATING SNOW WILL OCCUR AFTER 00Z THIS EVENING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CST THU DEC 12 2013
THE HIGHLIGHT OF THE SHORT TERM IS A BREAK FROM THE ARCTIC
AIR...ESPECIALLY SOUTHWEST AND SOUTH CENTRAL TODAY...FOLLOWED BY
ACCUMULATING SNOW TONIGHT NORTH CENTRAL.
CONTINUED POPS THROUGH 15 UTC ACROSS THE NORTHWEST BASED UPON
LATEST RADAR TRENDS THROUGH 0945 UTC AND THE 08 UTC RAP WHICH IS THE
JUST ABOUT THE ONLY DETERMINISTIC MODEL CAPTURING THE LIGHT SNOW
PROPAGATING IN FROM NORTHEAST MONTANA AND SOUTHEAST SASKATCHEWAN
THIS MORNING.
A QUASI-STATIONARY FRONT ACROSS NORTHWEST THROUGH SOUTHEAST NORTH
DAKOTA THIS MORNING WILL SLOWLY PROPAGATE SOUTHWEST THROUGH THE
DAY AS A COLD FRONT. ON THE WARM SIDE OF THIS BOUNDARY WIDESPREAD
HIGHS IN THE 20S...AND PERHAPS A FEW LOWER 30S ACROSS THE FAR
SOUTHWEST ARE EXPECTED. IN CONTRAST...HIGHS IN THE SINGLE DIGITS
ARE FORECAST ACROSS THE TURTLE MOUNTAINS...WHICH IS IN LINE WITH
THE 00 UTC GUIDANCE CONSENSUS. AS THE LOW LEVEL BAROCLINIC ZONE
STRENGTHENS LATE THIS AFTERNOON AND INTO THE EVENING AS THE
SOUTHERN PERIPHERY OF ARCTIC HIGH PRESSURE BUILDS INTO NORTHERN
NORTH DAKOTA...A BAND OF LIGHT TO MODERATE SNOW IS EXPECTED TO
DEVELOP ACROSS NORTH CENTRAL AND NORTHEAST NORTH DAKOTA AS
FRONTOGENETICAL FORCING INCREASES. ONE TO THREE INCHES OF SNOW IS
EXPECTED FOR THE US HIGHWAY 2 CORRIDOR ACROSS THE NORTH CENTRAL.
AT THIS TIME...WILL HIGHLIGHT THE EVENT WITH AN SPS...ALSO
MENTIONING WIND CHILLS TO 25 BELOW AS ARCTIC AIR BUILDS SOUTH
COUPLED WITH EASTERLY WINDS OF 10-15 KTS WITH THE TIGHT PRESSURE
GRADIENT ON THE SOUTHERN PERIPHERY OF THE SURFACE HIGH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 327 AM CST THU DEC 12 2013
THE MAIN FORECAST ISSUE IS TIMING AND COVERAGE OF SEVERAL LIGHT
SNOW EVENTS THROUGH THE PERIOD.
ON FRIDAY...ANOTHER SURGE OF ARCTIC AIR WILL SPREAD SOUTH ACROSS
THE STATE. LIGHT SNOW WILL CONTINUE FRIDAY...WITH ADDITIONAL
ACCUMULATION FOCUSED ON THE NORTHERN COUNTIES. 1 TO 2 MORE INCHES
WILL BE POSSIBLE THROUGH FRIDAY NIGHT...WITH GENERALLY A LIGHT
DUSTING POSSIBLE IN CENTRAL AND SOUTHERN NORTH DAKOTA. ANOTHER
WEAK SHORT WAVE MAY SUPPORT LIGHT ACCUMULATIONS AGAIN SATURDAY
NIGHT. WIND CHILLS AROUND 25 BELOW ZERO ARE POSSIBLE FRIDAY NIGHT
AND SATURDAY NIGHT ACROSS THE NORTH. LOOKING AHEAD...THERE IS SOME
UNCERTAINTY AS TO HOW FAR EAST THE UPPER RIDGE AND MILDER AIR WILL
PUSH. THE SOUTHWEST PART OF THE STATE...AT THE LEAST...SHOULD WARM
INTO THE 20S AND EVEN LOWER 30S FROM SUNDAY THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 643 AM CST THU DEC 12 2013
MVFR CONDITIONS IN LIGHT SNOW ARE POSSIBLE AT KISN AND KMOT THIS
MORNING. ANOTHER WEAK SYSTEM WILL IMPACT WESTERN AND CENTRAL NORTH
DAKOTA THIS AFTERNOON AND INTO THE NIGHT. MVFR CONDITIONS IN STRATUS
AND FOG WILL OVERTAKE THE AREA WITH IFR CONDITIONS IN SNOW
DEVELOPING AT KMOT TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE/LONG TERM...RP KINNEY
SHORT TERM/AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
441 AM CST THU DEC 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CST THU DEC 12 2013
THE HIGHLIGHT OF THE SHORT TERM IS A BREAK FROM THE ARCTIC
AIR...ESPECIALLY SOUTHWEST AND SOUTH CENTRAL TODAY...FOLLOWED BY
ACCUMULATING SNOW TONIGHT NORTH CENTRAL.
CONTINUED POPS THROUGH 15 UTC ACROSS THE NORTHWEST BASED UPON
LATEST RADAR TRENDS THROUGH 0945 UTC AND THE 08 UTC RAP WHICH IS THE
JUST ABOUT THE ONLY DETERMINISTIC MODEL CAPTURING THE LIGHT SNOW
PROPAGATING IN FROM NORTHEAST MONTANA AND SOUTHEAST SASKATCHEWAN
THIS MORNING.
A QUASI-STATIONARY FRONT ACROSS NORTHWEST THROUGH SOUTHEAST NORTH
DAKOTA THIS MORNING WILL SLOWLY PROPAGATE SOUTHWEST THROUGH THE
DAY AS A COLD FRONT. ON THE WARM SIDE OF THIS BOUNDARY WIDESPREAD
HIGHS IN THE 20S...AND PERHAPS A FEW LOWER 30S ACROSS THE FAR
SOUTHWEST ARE EXPECTED. IN CONTRAST...HIGHS IN THE SINGLE DIGITS
ARE FORECAST ACROSS THE TURTLE MOUNTAINS...WHICH IS IN LINE WITH
THE 00 UTC GUIDANCE CONSENSUS. AS THE LOW LEVEL BAROCLINIC ZONE
STRENGTHENS LATE THIS AFTERNOON AND INTO THE EVENING AS THE
SOUTHERN PERIPHERY OF ARCTIC HIGH PRESSURE BUILDS INTO NORTHERN
NORTH DAKOTA...A BAND OF LIGHT TO MODERATE SNOW IS EXPECTED TO
DEVELOP ACROSS NORTH CENTRAL AND NORTHEAST NORTH DAKOTA AS
FRONTOGENETICAL FORCING INCREASES. ONE TO THREE INCHES OF SNOW IS
EXPECTED FOR THE US HIGHWAY 2 CORRIDOR ACROSS THE NORTH CENTRAL.
AT THIS TIME...WILL HIGHLIGHT THE EVENT WITH AN SPS...ALSO
MENTIONING WIND CHILLS TO 25 BELOW AS ARCTIC AIR BUILDS SOUTH
COUPLED WITH EASTERLY WINDS OF 10-15 KTS WITH THE TIGHT PRESSURE
GRADIENT ON THE SOUTHERN PERIPHERY OF THE SURFACE HIGH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 327 AM CST THU DEC 12 2013
THE MAIN FORECAST ISSUE IS TIMING AND COVERAGE OF SEVERAL LIGHT
SNOW EVENTS THROUGH THE PERIOD.
ON FRIDAY...ANOTHER SURGE OF ARCTIC AIR WILL SPREAD SOUTH ACROSS
THE STATE. LIGHT SNOW WILL CONTINUE FRIDAY...WITH ADDITIONAL
ACCUMULATION FOCUSED ON THE NORTHERN COUNTIES. 1 TO 2 MORE INCHES
WILL BE POSSIBLE THROUGH FRIDAY NIGHT...WITH GENERALLY A LIGHT
DUSTING POSSIBLE IN CENTRAL AND SOUTHERN NORTH DAKOTA. ANOTHER
WEAK SHORT WAVE MAY SUPPORT LIGHT ACCUMULATIONS AGAIN SATURDAY
NIGHT. WIND CHILLS AROUND 25 BELOW ZERO ARE POSSIBLE FRIDAY NIGHT
AND SATURDAY NIGHT ACROSS THE NORTH. LOOKING AHEAD...THERE IS SOME
UNCERTAINTY AS TO HOW FAR EAST THE UPPER RIDGE AND MILDER AIR WILL
PUSH. THE SOUTHWEST PART OF THE STATE...AT THE LEAST...SHOULD WARM
INTO THE 20S AND EVEN LOWER 30S FROM SUNDAY THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 327 AM CST THU DEC 12 2013
IFR CONDITIONS IN LIGHT SNOW IS POSSIBLE AT KISN BETWEEN 09 AND 11
UTC THIS MORNING. ANOTHER WEAK SYSTEM WILL IMPACT WESTERN AND
CENTRAL NORTH DAKOTA THIS AFTERNOON AND INTO THE NIGHT. MVFR
CONDITIONS IN STRATUS ARE EXPECTED AT KISN/KJMS/KBIS/KDIK...WITH
IFR CONDITIONS IN SNOW AT KMOT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM/AVIATION...AYD
LONG TERM...RP KINNEY
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1238 AM CST THU DEC 12 2013
.UPDATE...
ISSUED AT 1237 AM CST THU DEC 12 2013
UPDATE TO INTRODUCE CHANCE POPS ACROSS NORTHWEST NORTH DAKOTA AS
AN AREA OF LIGHT SNOW CONTINUES TO COME INTO BETTER VIEW ON RADAR
ACROSS NORTHEAST MONTANA. THE 05 UTC RAP PROPAGATES THIS AREA OF
SNOW INTO NORTHWEST NORTH DAKOTA AFTER 08 UTC.
UPDATE ISSUED AT 948 PM CST WED DEC 11 2013
NO MAJOR CHANGES WERE MADE TO THE ONGOING FORECAST. ONLY ADJUSTED
THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT OBS/TRENDS. THE
UPDATED PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 713 PM CST WED DEC 11 2013
A WARM FRONT HAS MOVED ACROSS THE STATE FASTER THAN PREVIOUSLY
ANTICIPATED. AS A RESULT...UPDATED HOURLY TEMPS BASED ON CURRENT
OBS/TRENDS...AND ADJUSTED THE FORECAST LOWS UP ACROSS AREAS EAST
OF HIGHWAY 83 TONIGHT. THE REMAINING FORECAST ELEMENTS ARE IN GOOD
SHAPE. THE UPDATED PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 311 PM CST WED DEC 11 2013
WIND CHILLS HAVE FINALLY IMPROVED TO THE POINT THAT THE ADVISORY
CAN BE CANCELLED ACROSS THE NORTH CENTRAL. INCREASING CLOUDS EAST
OF A WARM FRONTAL BOUNDARY IN MONTANA WILL BRING STEADY OR RISING
TEMPERATURES TO THE DEVILS LAKE BASIN INTO THE JAMES RIVER VALLEY.
ALTHOUGH THEIR IS UNCERTAINTY ON THE AMOUNT OF DIURNAL
TREND...THERE IS THE POTENTIAL THE TEMPS WILL FALL OFF THIS
EVENING THEN BECOME STEADY OR SLOWLY RISE OVERNIGHT. OVERNIGHT
LOWS SHOULD BE 15 DEGREES OR MORE HIGHER THAN LAST
NIGHT...ESPECIALLY SOUTHWEST WHERE TEMPERATURES THURSDAY MORNING
WILL BE 35 TO 40 DEGREES WARMER THAN WEDNESDAY MORNING. KEPT A
SLIGHT CHANCE OF SNOW ACROSS THE NORTH CENTRAL INTO THE JAMES
RIVER VALLEY TONIGHT.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 311 PM CST WED DEC 11 2013
THE MAIN FORECAST CHALLENGE IS TIMING SEVERAL LIGHT SNOW EVENTS AND
TIMING OF COLD AND WARM FRONTS MOVING THROUGH THE REGION AS A BATTLE
CONTINUES BETWEEN ARCTIC AIR MOVING SOUTH FROM CANADA VERSUS THE
MILDER PACIFIC AIR TO OUR WEST/SOUTHWEST.
AFTER A RELATIVELY MILD DAY ON THURSDAY...MODEL CONSENSUS DEPICTS
THE ARRIVAL OF A SHORT WAVE IN NORTHWEST FLOW THURSDAY AFTERNOON AND
NIGHT. LIGHT SNOW IS EXPECTED ACROSS NORTHERN NORTH DAKOTA THURSDAY
NIGHT...WITH AN INCH OR 2 OF SNOW EXPECTED IN THE NORTH CENTRAL -
MAINLY FROM CROSBY TO THE TURTLE MOUNTAINS INCLUDING MINOT AND
RUGBY.
LIGHT SNOW IS FORECAST TO SPREAD SOUTHWARD ON FRIDAY AS ARCTIC AIR
SLIDES SOUTHEAST INTO THE RED RIVER VALLEY AND THE WESTERN EDGE OF
THE ARCTIC AIR IS OVER THE SOUTHWESTERN COUNTIES. LOOKING AT HIGHS
FROM AROUND 5 BELOW IN THE TURTLE MOUNTAINS TO AROUND 20 ABOVE ZERO
IN THE FAR SOUTHWEST. ALSO LOOKING AT SNOWFALL AMOUNTS DAYTIME
FRIDAY FROM 1/2 AN INCH TO 1 INCH OVER NORTHWESTERN AND CENTRAL
NORTH DAKOTA WITH LITTLE ACCUMULATION IN THE SOUTHWEST.
FRIDAY NIGHT THE ARCTIC HIGH CONTINUES SOUTHEASTWARD OUT OF NORTH
DAKOTA WITH ANOTHER ARCTIC HIGH OVER THE CANADIAN FRONT RANGE POISED
TO MOVE SOUTH. LOWS IN SOUTHWESTERN NORTH DAKOTA SHOULD BE IN THE
SINGLE DIGITS ABOVE ZERO...BUT FARTHER NORTH AND EAST EXPECT LOWS
FROM 5 TO 10 BELOW MOST AREAS. STILL SOME LIGHT SNOW AMOUNTS
EXPECTED - MAINLY NORTH.
THUS THURSDAY NIGHT THROUGH FRIDAY NIGHT SNOW AMOUNTS SHOULD BE
GENERALLY IN THE 1-3 INCH RANGE ACROSS NORTHERN NORTH DAKOTA...WITH
AROUND 1/2 INCH OF SNOW ACROSS THE SOUTH CENTRAL...AND LITTLE
ACCUMULATION IN THE SOUTHWEST.
FOR THE WEEKEND INTO NEXT WEEK:
ON SATURDAY NIGHT ANOTHER ARCTIC COLD FRONT MOVES THROUGH THE
FORECAST AREA...THEN PUSHES EAST OF THE REGION ON SUNDAY.
A WARM-UP PERIOD IS THEN FORECAST TO ENSUE SUNDAY THROUGH
TUESDAY...BUT YET ANOTHER ARCTIC OUTBREAK IS IN THE OFFING FOR
WEDNESDAY THROUGH THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1237 AM CST THU DEC 12 2013
IFR CONDITIONS IN LIGHT SNOW IS POSSIBLE AT KISN BETWEEN 08 AND 11
UTC THURSDAY MORNING. ANOTHER WEAK SYSTEM WILL IMPACT WESTERN AND
CENTRAL NORTH DAKOTA THURSDAY AFTERNOON AND INTO THE NIGHT. MVFR
CONDITIONS IN STRATUS ARE EXPECTED AT KISN/KJMS/KBIS...WITH IFR
CONDITIONS IN SNOW AT KMOT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...WAA/JV
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
843 PM CST FRI DEC 13 2013
.UPDATE...
WILL UPDATE FOR PATCHY DENSE FOG IN AREAS EAST OF A LINE FROM
LAMPASAS TO GRANBURY TO BOWIE...AND ISSUE ADVISORY. WILL ALSO END
THE PRECIP AT 10 PM BASED ON EXTRAPOLATION OF CURRENT SHOWERS IN
THE EAST. IN AREAS WITH ICE...THE 40 DEW POINT AIR AND THE 30
DEGREE ICE WILL AID IN FOG FORMATION...AND MANY OTHER AREAS JUST
RECEIVED RAIN WHICH WILL ALSO AID IN FOG FORMATION. THE FRONT
SHOULD INCREASE VISIBILITY STARTING BEFORE SUNRISE FROM NORTHWEST
TO SOUTHEAST. THE HEAT ISLAND WILL ALSO LIKELY KEEP VISIBILITIES
ABOVE ADVISORY CRITERIA IN THE MIDDLE OF THE DFW METROPLEX.
UPDATE OUT SHORTLY. 84
&&
.AVIATION...
FOR THE 00Z TAFS...FLIGHT CATEGORY RESTRICTIONS ASSOCIATED WITH AN
APPROACHING COLD FRONT AND ONGOING LIGHT RAINFALL ACROSS THE
REGION ARE THE PRIMARY FORECAST CONCERNS.
23 TO 00Z OBSERVATIONS WERE HOVERING AROUND HIGH IFR TO LOW MVFR
CONDITIONS ACROSS THE DFW METROPLEX. OPTED TO GO WITH IFR CIGS
WITH MVFR VSBYS TO START OFF THE TAFS AS FORECAST SOUNDINGS ALL
SHOW CIGS LOWERING FROM 00 TO 03Z. LIGHT RAINFALL WILL LIKELY
PERSIST THROUGH MIDNIGHT BEFORE DRY AIR STARTS TO BUILD OVER THE
REGION BEHIND AN EXITING UPPER LEVEL DISTURBANCE. LIGHT
RAIN/DRIZZLE CONCERNS THROUGH MIDNIGHT PROMPTED THE CONTINUATION
OF THE MVFR VSBYS FOR THE START OF THE FORECAST.
SURFACE LOW PRESSURE IS EXPECTED TO SWEEP EAST ACROSS THE REGION
JUST OUT AHEAD OF A COLD FRONT. THIS WILL CAUSE WINDS TO VEER AND
DROP IN INTENSITY FOR A FEW HOURS BEFORE THE COLD FRONT ARRIVES.
THIS DROP IN WIND SPEEDS MAY ALLOW FOR SOME SHALLOW GROUND FOG TO
DEVELOP...SO WENT AHEAD WITH IFR VSBYS FOR THE WINDOW IN BETWEEN
MIDNIGHT AND WHEN THE FRONT IS EXPECTED TO ARRIVE...OR AROUND 10Z.
FORECAST SOUNDINGS INDICATE IFR CIGS AND ARE INCONCLUSIVE ON FOG
POTENTIAL. THE RAP AND LAMP GUIDANCE CERTAINLY HIT THE FOG
POTENTIAL HARD...BUT WITH LOW STRATUS IN PLACE...RADIATIONAL
COOLING WILL BE STUNTED WHICH SHOULD GENERALLY PREVENT DENSE FOG
FROM DEVELOPING AROUND AREA AIRPORTS AFTER MIDNIGHT. AT THIS POINT
WILL WAIT AND SEE IF IT LOOKS LIKE SHALLOW/GROUND FOG IS GOING TO
BE MORE EXPANSIVE TONIGHT...IF SO WILL HIT THE FOG POTENTIAL AND
VISIBILITIES HARDER AT THE 03 OR 06Z TAF ISSUANCES.
BEHIND THE FRONT...WINDS ARE EXPECTED TO BE STRONG ENOUGH TO CAUSE
ANY FOG THAT MANAGES TO DEVELOP TO DISSIPATE QUICKLY. WENT AHEAD
WITH VFR VSBYS AFTER THE FRONTAL PASSAGE AS A RESULT. CIGS WILL
REMAIN IFR RIGHT AFTER THE FRONTAL PASSAGE...AND WILL RISE TO MVFR
AND EVENTUALLY VFR BY TOMORROW AFTERNOON AS DRIER AIR WORKS INTO
THE REGION.
CAVANAUGH
&&
.PREV UPDATE...
.UPDATE...
A WEAK FRONT RUNS FROM BOWIE TO ROCKWALL TO TYLER. OVERNIGHT...A
WEAK SURFACE LOW IS PROGGED TO RIDE SOUTHEAST DOWN THIS BOUNDARY.
LIGHTER FOG IS LIKELY ACROSS MUCH OF THE REST OF NORTH TEXAS BUT
AREAS NORTH OF THAT FRONT WILL GET WEAK ADVECTION OF HIGHER DEW
POINT AIR AS THAT SURFACE LOW APPROACHES. HAVE ADDED PATCHY FOG
AFTER MIDNIGHT NORTHEAST OF THE LINE THINKING THAT THIS AREA WILL
HAVE THE BEST CHANCE TO SEE VISIBILITY DROP TO A MILE OR LESS. THE
COLD FRONT PROGGED FOR THE MORNING SHOULD MIX OUT THE LOW LEVELS
AND IMPROVE VISIBILITIES QUICKLY. 84
&&
.PREV DISCUSSION... /ISSUED 349 PM CST FRI DEC 13 2013/
WATER VAPOR LOOP SHOWS A WELL DEFINED SHORTWAVE MOVING INTO THE
TEXAS PANHANDLE NOW. NORTH TEXAS IS CURRENTLY LOCATED IN A REGION
OF STRONG LIFT...BUT DEEPER MOISTURE IS ALREADY BEING SHUNTED EAST
OF THE AREA AS A DRY SLOT ALOFT WORKS THROUGH FROM THE SOUTHWEST.
HOWEVER THE LOW LEVELS REMAIN MOIST AND SATURATED AND THIS LIFT
WILL CONTINUE TO RESULT IN SCATTERED LOW TOPPED SHOWERS AND PATCHY
DRIZZLE OVER THE NEXT FEW HOURS. MUCH OF THIS ACTIVITY WILL END AS
THE BEST LIFT MOVES EAST OF THE CWA...AND FIRST PERIOD POPS WHICH
BEGIN AFTER 6PM WILL BE ON THE LOW SIDE FOR THE CENTRAL/WESTERN
CWA. A SECOND STRONG SHORTWAVE RIGHT ON THE HEELS OF THE FIRST
WILL APPROACH THE AREA LATE TONIGHT WHICH WILL ENSURE SOUTHERLY
WINDS THIS EVENING AND WARM/MOIST ADVECTION NEAR OR JUST ABOVE THE
SURFACE. THE WINDS AND WARM ADVECTION WILL LIKELY LIMIT THE
POTENTIAL FOR FOG TONIGHT...DESPITE A VERY FAVORABLE PROFILE...BUT
MAY ENHANCE THE POTENTIAL FOR LOW CLOUDS AND DRIZZLE. TEMPS WILL
LIKELY REMAIN NEARLY STEADY TONIGHT IN THE 40S AHEAD A COLD FRONT.
A SURFACE LOW AND COLD FRONT WILL MOVE THROUGH NORTH TEXAS AFTER 3
AM WITH WINDS BECOMING NORTH AT 15 MPH BY SUNRISE. STRONG
FRONTOGENETIC LIFTING OF A SATURATED LAYER NEAR THE SURFACE WILL
RESULT IN WIDESPREAD LOW CLOUDS AND SOME DRIZZLE BEHIND THE FRONT
SATURDAY MORNING. CLOUDS WILL CLEAR FROM NORTHWEST TO SOUTHEAST
DURING THE MID-LATE AFTERNOON HOURS ON SATURDAY. DUE TO THE CLOUDS
AND COLD ADVECTION BEHIND THE FRONT HIGHS SATURDAY WILL LIKELY
REMAIN IN THE LOW TO MID 40S. HOWEVER RADIATIONAL COOLING LOOK
GOOD SATURDAY NIGHT WITH LOWS FALLING INTO THE 20S AREA WIDE.
A GRADUAL MODERATION IN TEMPERATURES IS EXPECTED SUNDAY INTO THE
MIDDLE OF NEXT WEEK. GENERALLY CLEAR SKIES AND DRY AIR WILL ALLOW
FOR WARMER/MILD DAYS AND COOL NIGHTS. HIGHS SUNDAY WILL BE IN THE
50S FOR MOST AREAS...BUT 60S ARE EXPECTED MONDAY AND BEYOND. BY
WEDNESDAY SOUTHERLY WINDS WILL INCREASE AND BEGIN TO BRING HIGHER
DEWPOINTS INTO THE AREA WITH LOWS WELL ABOVE NORMAL IN THE 50S.
MEANWHILE...ANOTHER ARCTIC AIRMASS WILL BE GATHERING ACROSS CANADA
AS A POLAR VORTEX TRACKS FROM SIBERIA...ACROSS THE NORTH
POLE...AND INTO THE HUDSON BAY AREA BY NEXT WEEKEND. THIS UPPER
LEVEL PATTERN WILL RESULT IN ANTI-CYCLOGENESIS AND THE DEVELOPMENT
OF AN INTENSE ARCTIC HIGH PRESSURE CELL THAT DROPS INTO THE PLAINS
BY THURSDAY. THIS FRONT WOULD LIKELY TRACK THROUGH NORTH TEXAS ON
FRIDAY WITH TEMPERATURES AGAIN FALLING TO WELL BELOW NORMAL NEXT
WEEKEND. WE HAVE SEEN THE MODELS WAFFLE A BIT ON JUST HOW COLD
THIS AIRMASS WILL BE OVER THE LAST FEW DAYS FOR NORTH TEXAS. WHILE
THIS WILL SURELY BE ANOTHER NOTEWORTHY COLD SNAP FOR MUCH OF THE
COUNTRY...AS FAR AS NORTH TEXAS IS CONCERNED...THE MODELS ARE NOT
FORECASTING AN UPPER LEVEL PATTERN THAT WOULD RESULT IN ANY TYPE
OF RECORD BREAKING COLD HERE. AT THIS POINT I DONT SEE ANY
COMPELLING REASON TO BELIEVE THIS WILL BE ANY COLDER THAN OUR LAST
ARCTIC SPELL. THIS IS BECAUSE ALL MODELS HAVE BEEN VERY CONSISTENT
ON STRONG SURFACE LOW CYCLOGENESIS ACROSS THE PLAINS AND GREAT
LAKES WHICH WILL SERVE TO KEEP THE UPPER LEVEL LONGWAVE TROUGH
MORE PROGRESSIVE. PROGRESSIVE LONGWAVE TROUGHS DONT LET AS MUCH
COLD AIR DROP THIS FAR SOUTH AS SLOW MOVING OR STATIONARY UPPER
TROUGHS DO. ESSENTIALLY IN THIS UPPER LEVEL PATTERN...THE CORE OF
THE COLD AIR ENDS UP HEADING MORE EAST THAN SOUTH ONCE IT ARRIVES
INTO THE PLAINS AND MIDWEST.
CONCERNING WINTER PRECIP POTENTIAL...THERE IS STILL A TREMENDOUS
AMOUNT OF UNCERTAINTY WITH THE SHORTER WAVELENGTH FEATURES THAT
WOULD POSSIBLY PROVIDE THE LIFT AND MOISTURE REQUIRED FOR POST
FRONTAL WINTER PRECIP. IT WILL CERTAINLY BE COLD ENOUGH OVER NORTH
TEXAS FOR WINTER PRECIP AND LIKELY SNOW BY SATURDAY. THE KEY AT
THIS POINT IS VERY WEAK SHORTWAVE TROUGH THAT IS CURRENTLY OVER
JAPAN. THIS SYSTEM IS FORECAST TO REMAIN A RATHER INNOCUOUS POCKET
OF POTENTIAL VORTICITY FOR THE NEXT SEVERAL DAYS AS IT TRACKS
ACROSS THE PACIFIC...BUT IS FORECAST TO AMPLIFY/INTENSIFY AS IT
ARRIVES INTO THE PACIFIC NORTHWEST WEDNESDAY AND THURSDAY. THE 12Z
GFS/CANADIAN PHASE THIS ENERGY INTO THE BROADER LONGWAVE TROUGH...
AND SUGGEST ALL PRECIP WILL END BEFORE THE AIR GETS COLD ENOUGH
FOR SNOW. THE ECMWF AND SEVERAL GFS ENSEMBLE MEMBERS INDICATE
THAT THE ENERGY WITH THIS SYSTEM WILL REMAIN DETACHED FROM THE
MAIN UPPER TROUGH AND FORM INTO A CLOSED UPPER LOW WHICH TRACKS
OVER THE REGION SATURDAY. THIS SOLUTION WOULD RESULT IN A CHANCE
OF SNOW...ESPECIALLY OVER THE NORTHWEST/NORTHERN ZONES SATURDAY.
RIGHT NOW BASED ON ALL ENSEMBLE AND AVAILABLE OPERATIONAL RUNS WE
WOULD ESTIMATE THE CHANCE OF SNOW IN PART OF OUR CWA NEXT
SATURDAY AT 20 PERCENT. OF COURSE AT THIS TIME RANGE THERE IS
PLENTY OF TIME FOR MODELS TO TREND IN EITHER DIRECTION...SO WE
WILL HAVE TO WAIT AND SEE.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 39 43 29 54 35 / 10 10 0 0 0
WACO, TX 39 45 28 55 30 / 10 10 0 0 0
PARIS, TX 39 43 26 49 31 / 20 10 0 0 0
DENTON, TX 37 43 24 54 30 / 10 10 0 0 0
MCKINNEY, TX 38 42 25 52 28 / 20 10 0 0 0
DALLAS, TX 39 42 30 53 37 / 10 10 0 0 0
TERRELL, TX 40 43 27 52 30 / 20 10 0 0 0
CORSICANA, TX 42 44 28 53 34 / 20 10 0 0 0
TEMPLE, TX 40 46 29 56 30 / 10 10 0 0 0
MINERAL WELLS, TX 35 44 25 58 30 / 5 10 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 8 AM CST SATURDAY FOR TXZ091>095-
102>107-117>123-131>135-143>148-156>162-174-175.
&&
$$
/
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
639 PM CST FRI DEC 13 2013
.UPDATE...
A WEAK FRONT RUNS FROM BOWIE TO ROCKWALL TO TYLER. OVERNIGHT...A
WEAK SURFACE LOW IS PROGGED TO RIDE SOUTHEAST DOWN THIS BOUNDARY.
LIGHTER FOG IS LIKELY ACROSS MUCH OF THE REST OF NORTH TEXAS BUT
AREAS NORTH OF THAT FRONT WILL GET WEAK ADVECTION OF HIGHER DEW
POINT AIR AS THAT SURFACE LOW APPROACHES. HAVE ADDED PATCHY FOG
AFTER MIDNIGHT NORTHEAST OF THE LINE THINKING THAT THIS AREA WILL
HAVE THE BEST CHANCE TO SEE VISIBILITY DROP TO A MILE OR LESS. THE
COLD FRONT PROGGED FOR THE MORNING SHOULD MIX OUT THE LOW LEVELS
AND IMPROVE VISIBILITIES QUICKLY. 84
&&
.AVIATION...
FOR THE 00Z TAFS...FLIGHT CATEGORY RESTRICTIONS ASSOCIATED WITH AN
APPROACHING COLD FRONT AND ONGOING LIGHT RAINFALL ACROSS THE
REGION ARE THE PRIMARY FORECAST CONCERNS.
23 TO 00Z OBSERVATIONS WERE HOVERING AROUND HIGH IFR TO LOW MVFR
CONDITIONS ACROSS THE DFW METROPLEX. OPTED TO GO WITH IFR CIGS
WITH MVFR VSBYS TO START OFF THE TAFS AS FORECAST SOUNDINGS ALL
SHOW CIGS LOWERING FROM 00 TO 03Z. LIGHT RAINFALL WILL LIKELY
PERSIST THROUGH MIDNIGHT BEFORE DRY AIR STARTS TO BUILD OVER THE
REGION BEHIND AN EXITING UPPER LEVEL DISTURBANCE. LIGHT
RAIN/DRIZZLE CONCERNS THROUGH MIDNIGHT PROMPTED THE CONTINUATION
OF THE MVFR VSBYS FOR THE START OF THE FORECAST.
SURFACE LOW PRESSURE IS EXPECTED TO SWEEP EAST ACROSS THE REGION
JUST OUT AHEAD OF A COLD FRONT. THIS WILL CAUSE WINDS TO VEER AND
DROP IN INTENSITY FOR A FEW HOURS BEFORE THE COLD FRONT ARRIVES.
THIS DROP IN WIND SPEEDS MAY ALLOW FOR SOME SHALLOW GROUND FOG TO
DEVELOP...SO WENT AHEAD WITH IFR VSBYS FOR THE WINDOW IN BETWEEN
MIDNIGHT AND WHEN THE FRONT IS EXPECTED TO ARRIVE...OR AROUND 10Z.
FORECAST SOUNDINGS INDICATE IFR CIGS AND ARE INCONCLUSIVE ON FOG
POTENTIAL. THE RAP AND LAMP GUIDANCE CERTAINLY HIT THE FOG
POTENTIAL HARD...BUT WITH LOW STRATUS IN PLACE...RADIATIONAL
COOLING WILL BE STUNTED WHICH SHOULD GENERALLY PREVENT DENSE FOG
FROM DEVELOPING AROUND AREA AIRPORTS AFTER MIDNIGHT. AT THIS POINT
WILL WAIT AND SEE IF IT LOOKS LIKE SHALLOW/GROUND FOG IS GOING TO
BE MORE EXPANSIVE TONIGHT...IF SO WILL HIT THE FOG POTENTIAL AND
VISIBILITIES HARDER AT THE 03 OR 06Z TAF ISSUANCES.
BEHIND THE FRONT...WINDS ARE EXPECTED TO BE STRONG ENOUGH TO CAUSE
ANY FOG THAT MANAGES TO DEVELOP TO DISSIPATE QUICKLY. WENT AHEAD
WITH VFR VSBYS AFTER THE FRONTAL PASSAGE AS A RESULT. CIGS WILL
REMAIN IFR RIGHT AFTER THE FRONTAL PASSAGE...AND WILL RISE TO MVFR
AND EVENTUALLY VFR BY TOMORROW AFTERNOON AS DRIER AIR WORKS INTO
THE REGION.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 349 PM CST FRI DEC 13 2013/
WATER VAPOR LOOP SHOWS A WELL DEFINED SHORTWAVE MOVING INTO THE
TEXAS PANHANDLE NOW. NORTH TEXAS IS CURRENTLY LOCATED IN A REGION
OF STRONG LIFT...BUT DEEPER MOISTURE IS ALREADY BEING SHUNTED EAST
OF THE AREA AS A DRY SLOT ALOFT WORKS THROUGH FROM THE SOUTHWEST.
HOWEVER THE LOW LEVELS REMAIN MOIST AND SATURATED AND THIS LIFT
WILL CONTINUE TO RESULT IN SCATTERED LOW TOPPED SHOWERS AND PATCHY
DRIZZLE OVER THE NEXT FEW HOURS. MUCH OF THIS ACTIVITY WILL END AS
THE BEST LIFT MOVES EAST OF THE CWA...AND FIRST PERIOD POPS WHICH
BEGIN AFTER 6PM WILL BE ON THE LOW SIDE FOR THE CENTRAL/WESTERN
CWA. A SECOND STRONG SHORTWAVE RIGHT ON THE HEELS OF THE FIRST
WILL APPROACH THE AREA LATE TONIGHT WHICH WILL ENSURE SOUTHERLY
WINDS THIS EVENING AND WARM/MOIST ADVECTION NEAR OR JUST ABOVE THE
SURFACE. THE WINDS AND WARM ADVECTION WILL LIKELY LIMIT THE
POTENTIAL FOR FOG TONIGHT...DESPITE A VERY FAVORABLE PROFILE...BUT
MAY ENHANCE THE POTENTIAL FOR LOW CLOUDS AND DRIZZLE. TEMPS WILL
LIKELY REMAIN NEARLY STEADY TONIGHT IN THE 40S AHEAD A COLD FRONT.
A SURFACE LOW AND COLD FRONT WILL MOVE THROUGH NORTH TEXAS AFTER 3
AM WITH WINDS BECOMING NORTH AT 15 MPH BY SUNRISE. STRONG
FRONTOGENETIC LIFTING OF A SATURATED LAYER NEAR THE SURFACE WILL
RESULT IN WIDESPREAD LOW CLOUDS AND SOME DRIZZLE BEHIND THE FRONT
SATURDAY MORNING. CLOUDS WILL CLEAR FROM NORTHWEST TO SOUTHEAST
DURING THE MID-LATE AFTERNOON HOURS ON SATURDAY. DUE TO THE CLOUDS
AND COLD ADVECTION BEHIND THE FRONT HIGHS SATURDAY WILL LIKELY
REMAIN IN THE LOW TO MID 40S. HOWEVER RADIATIONAL COOLING LOOK
GOOD SATURDAY NIGHT WITH LOWS FALLING INTO THE 20S AREA WIDE.
A GRADUAL MODERATION IN TEMPERATURES IS EXPECTED SUNDAY INTO THE
MIDDLE OF NEXT WEEK. GENERALLY CLEAR SKIES AND DRY AIR WILL ALLOW
FOR WARMER/MILD DAYS AND COOL NIGHTS. HIGHS SUNDAY WILL BE IN THE
50S FOR MOST AREAS...BUT 60S ARE EXPECTED MONDAY AND BEYOND. BY
WEDNESDAY SOUTHERLY WINDS WILL INCREASE AND BEGIN TO BRING HIGHER
DEWPOINTS INTO THE AREA WITH LOWS WELL ABOVE NORMAL IN THE 50S.
MEANWHILE...ANOTHER ARCTIC AIRMASS WILL BE GATHERING ACROSS CANADA
AS A POLAR VORTEX TRACKS FROM SIBERIA...ACROSS THE NORTH
POLE...AND INTO THE HUDSON BAY AREA BY NEXT WEEKEND. THIS UPPER
LEVEL PATTERN WILL RESULT IN ANTI-CYCLOGENESIS AND THE DEVELOPMENT
OF AN INTENSE ARCTIC HIGH PRESSURE CELL THAT DROPS INTO THE PLAINS
BY THURSDAY. THIS FRONT WOULD LIKELY TRACK THROUGH NORTH TEXAS ON
FRIDAY WITH TEMPERATURES AGAIN FALLING TO WELL BELOW NORMAL NEXT
WEEKEND. WE HAVE SEEN THE MODELS WAFFLE A BIT ON JUST HOW COLD
THIS AIRMASS WILL BE OVER THE LAST FEW DAYS FOR NORTH TEXAS. WHILE
THIS WILL SURELY BE ANOTHER NOTEWORTHY COLD SNAP FOR MUCH OF THE
COUNTRY...AS FAR AS NORTH TEXAS IS CONCERNED...THE MODELS ARE NOT
FORECASTING AN UPPER LEVEL PATTERN THAT WOULD RESULT IN ANY TYPE
OF RECORD BREAKING COLD HERE. AT THIS POINT I DONT SEE ANY
COMPELLING REASON TO BELIEVE THIS WILL BE ANY COLDER THAN OUR LAST
ARCTIC SPELL. THIS IS BECAUSE ALL MODELS HAVE BEEN VERY CONSISTENT
ON STRONG SURFACE LOW CYCLOGENESIS ACROSS THE PLAINS AND GREAT
LAKES WHICH WILL SERVE TO KEEP THE UPPER LEVEL LONGWAVE TROUGH
MORE PROGRESSIVE. PROGRESSIVE LONGWAVE TROUGHS DONT LET AS MUCH
COLD AIR DROP THIS FAR SOUTH AS SLOW MOVING OR STATIONARY UPPER
TROUGHS DO. ESSENTIALLY IN THIS UPPER LEVEL PATTERN...THE CORE OF
THE COLD AIR ENDS UP HEADING MORE EAST THAN SOUTH ONCE IT ARRIVES
INTO THE PLAINS AND MIDWEST.
CONCERNING WINTER PRECIP POTENTIAL...THERE IS STILL A TREMENDOUS
AMOUNT OF UNCERTAINTY WITH THE SHORTER WAVELENGTH FEATURES THAT
WOULD POSSIBLY PROVIDE THE LIFT AND MOISTURE REQUIRED FOR POST
FRONTAL WINTER PRECIP. IT WILL CERTAINLY BE COLD ENOUGH OVER NORTH
TEXAS FOR WINTER PRECIP AND LIKELY SNOW BY SATURDAY. THE KEY AT
THIS POINT IS VERY WEAK SHORTWAVE TROUGH THAT IS CURRENTLY OVER
JAPAN. THIS SYSTEM IS FORECAST TO REMAIN A RATHER INNOCUOUS POCKET
OF POTENTIAL VORTICITY FOR THE NEXT SEVERAL DAYS AS IT TRACKS
ACROSS THE PACIFIC...BUT IS FORECAST TO AMPLIFY/INTENSIFY AS IT
ARRIVES INTO THE PACIFIC NORTHWEST WEDNESDAY AND THURSDAY. THE 12Z
GFS/CANADIAN PHASE THIS ENERGY INTO THE BROADER LONGWAVE TROUGH...
AND SUGGEST ALL PRECIP WILL END BEFORE THE AIR GETS COLD ENOUGH
FOR SNOW. THE ECMWF AND SEVERAL GFS ENSEMBLE MEMBERS INDICATE
THAT THE ENERGY WITH THIS SYSTEM WILL REMAIN DETACHED FROM THE
MAIN UPPER TROUGH AND FORM INTO A CLOSED UPPER LOW WHICH TRACKS
OVER THE REGION SATURDAY. THIS SOLUTION WOULD RESULT IN A CHANCE
OF SNOW...ESPECIALLY OVER THE NORTHWEST/NORTHERN ZONES SATURDAY.
RIGHT NOW BASED ON ALL ENSEMBLE AND AVAILABLE OPERATIONAL RUNS WE
WOULD ESTIMATE THE CHANCE OF SNOW IN PART OF OUR CWA NEXT
SATURDAY AT 20 PERCENT. OF COURSE AT THIS TIME RANGE THERE IS
PLENTY OF TIME FOR MODELS TO TREND IN EITHER DIRECTION...SO WE
WILL HAVE TO WAIT AND SEE.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 39 43 29 54 35 / 20 10 0 0 0
WACO, TX 39 45 28 55 30 / 10 10 0 0 0
PARIS, TX 39 43 26 49 31 / 40 10 0 0 0
DENTON, TX 37 43 24 54 30 / 20 10 0 0 0
MCKINNEY, TX 38 42 25 52 28 / 20 10 0 0 0
DALLAS, TX 39 42 30 53 37 / 20 10 0 0 0
TERRELL, TX 40 43 27 52 30 / 30 10 0 0 0
CORSICANA, TX 42 44 28 53 34 / 20 10 0 0 0
TEMPLE, TX 40 46 29 56 30 / 5 10 0 0 0
MINERAL WELLS, TX 35 44 25 58 30 / 20 10 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
555 PM CST FRI DEC 13 2013
.AVIATION...
FOR THE 00Z TAFS...FLIGHT CATEGORY RESTRICTIONS ASSOCIATED WITH AN
APPROACHING COLD FRONT AND ONGOING LIGHT RAINFALL ACROSS THE
REGION ARE THE PRIMARY FORECAST CONCERNS.
23 TO 00Z OBSERVATIONS WERE HOVERING AROUND HIGH IFR TO LOW MVFR
CONDITIONS ACROSS THE DFW METROPLEX. OPTED TO GO WITH IFR CIGS
WITH MVFR VSBYS TO START OFF THE TAFS AS FORECAST SOUNDINGS ALL
SHOW CIGS LOWERING FROM 00 TO 03Z. LIGHT RAINFALL WILL LIKELY
PERSIST THROUGH MIDNIGHT BEFORE DRY AIR STARTS TO BUILD OVER THE
REGION BEHIND AN EXITING UPPER LEVEL DISTURBANCE. LIGHT
RAIN/DRIZZLE CONCERNS THROUGH MIDNIGHT PROMPTED THE CONTINUATION
OF THE MVFR VSBYS FOR THE START OF THE FORECAST.
SURFACE LOW PRESSURE IS EXPECTED TO SWEEP EAST ACROSS THE REGION
JUST OUT AHEAD OF A COLD FRONT. THIS WILL CAUSE WINDS TO VEER AND
DROP IN INTENSITY FOR A FEW HOURS BEFORE THE COLD FRONT ARRIVES.
THIS DROP IN WIND SPEEDS MAY ALLOW FOR SOME SHALLOW GROUND FOG TO
DEVELOP...SO WENT AHEAD WITH IFR VSBYS FOR THE WINDOW IN BETWEEN
MIDNIGHT AND WHEN THE FRONT IS EXPECTED TO ARRIVE...OR AROUND 10Z.
FORECAST SOUNDINGS INDICATE IFR CIGS AND ARE INCONCLUSIVE ON FOG
POTENTIAL. THE RAP AND LAMP GUIDANCE CERTAINLY HIT THE FOG
POTENTIAL HARD...BUT WITH LOW STRATUS IN PLACE...RADIATIONAL
COOLING WILL BE STUNTED WHICH SHOULD GENERALLY PREVENT DENSE FOG
FROM DEVELOPING AROUND AREA AIRPORTS AFTER MIDNIGHT. AT THIS POINT
WILL WAIT AND SEE IF IT LOOKS LIKE SHALLOW/GROUND FOG IS GOING TO
BE MORE EXPANSIVE TONIGHT...IF SO WILL HIT THE FOG POTENTIAL AND
VISIBILITIES HARDER AT THE 03 OR 06Z TAF ISSUANCES.
BEHIND THE FRONT...WINDS ARE EXPECTED TO BE STRONG ENOUGH TO CAUSE
ANY FOG THAT MANAGES TO DEVELOP TO DISSIPATE QUICKLY. WENT AHEAD
WITH VFR VSBYS AFTER THE FRONTAL PASSAGE AS A RESULT. CIGS WILL
REMAIN IFR RIGHT AFTER THE FRONTAL PASSAGE...AND WILL RISE TO MVFR
AND EVENTUALLY VFR BY TOMORROW AFTERNOON AS DRIER AIR WORKS INTO
THE REGION.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 349 PM CST FRI DEC 13 2013/
WATER VAPOR LOOP SHOWS A WELL DEFINED SHORTWAVE MOVING INTO THE
TEXAS PANHANDLE NOW. NORTH TEXAS IS CURRENTLY LOCATED IN A REGION
OF STRONG LIFT...BUT DEEPER MOISTURE IS ALREADY BEING SHUNTED EAST
OF THE AREA AS A DRY SLOT ALOFT WORKS THROUGH FROM THE SOUTHWEST.
HOWEVER THE LOW LEVELS REMAIN MOIST AND SATURATED AND THIS LIFT
WILL CONTINUE TO RESULT IN SCATTERED LOW TOPPED SHOWERS AND PATCHY
DRIZZLE OVER THE NEXT FEW HOURS. MUCH OF THIS ACTIVITY WILL END AS
THE BEST LIFT MOVES EAST OF THE CWA...AND FIRST PERIOD POPS WHICH
BEGIN AFTER 6PM WILL BE ON THE LOW SIDE FOR THE CENTRAL/WESTERN
CWA. A SECOND STRONG SHORTWAVE RIGHT ON THE HEELS OF THE FIRST
WILL APPROACH THE AREA LATE TONIGHT WHICH WILL ENSURE SOUTHERLY
WINDS THIS EVENING AND WARM/MOIST ADVECTION NEAR OR JUST ABOVE THE
SURFACE. THE WINDS AND WARM ADVECTION WILL LIKELY LIMIT THE
POTENTIAL FOR FOG TONIGHT...DESPITE A VERY FAVORABLE PROFILE...BUT
MAY ENHANCE THE POTENTIAL FOR LOW CLOUDS AND DRIZZLE. TEMPS WILL
LIKELY REMAIN NEARLY STEADY TONIGHT IN THE 40S AHEAD A COLD FRONT.
A SURFACE LOW AND COLD FRONT WILL MOVE THROUGH NORTH TEXAS AFTER 3
AM WITH WINDS BECOMING NORTH AT 15 MPH BY SUNRISE. STRONG
FRONTOGENETIC LIFTING OF A SATURATED LAYER NEAR THE SURFACE WILL
RESULT IN WIDESPREAD LOW CLOUDS AND SOME DRIZZLE BEHIND THE FRONT
SATURDAY MORNING. CLOUDS WILL CLEAR FROM NORTHWEST TO SOUTHEAST
DURING THE MID-LATE AFTERNOON HOURS ON SATURDAY. DUE TO THE CLOUDS
AND COLD ADVECTION BEHIND THE FRONT HIGHS SATURDAY WILL LIKELY
REMAIN IN THE LOW TO MID 40S. HOWEVER RADIATIONAL COOLING LOOK
GOOD SATURDAY NIGHT WITH LOWS FALLING INTO THE 20S AREA WIDE.
A GRADUAL MODERATION IN TEMPERATURES IS EXPECTED SUNDAY INTO THE
MIDDLE OF NEXT WEEK. GENERALLY CLEAR SKIES AND DRY AIR WILL ALLOW
FOR WARMER/MILD DAYS AND COOL NIGHTS. HIGHS SUNDAY WILL BE IN THE
50S FOR MOST AREAS...BUT 60S ARE EXPECTED MONDAY AND BEYOND. BY
WEDNESDAY SOUTHERLY WINDS WILL INCREASE AND BEGIN TO BRING HIGHER
DEWPOINTS INTO THE AREA WITH LOWS WELL ABOVE NORMAL IN THE 50S.
MEANWHILE...ANOTHER ARCTIC AIRMASS WILL BE GATHERING ACROSS CANADA
AS A POLAR VORTEX TRACKS FROM SIBERIA...ACROSS THE NORTH
POLE...AND INTO THE HUDSON BAY AREA BY NEXT WEEKEND. THIS UPPER
LEVEL PATTERN WILL RESULT IN ANTI-CYCLOGENESIS AND THE DEVELOPMENT
OF AN INTENSE ARCTIC HIGH PRESSURE CELL THAT DROPS INTO THE PLAINS
BY THURSDAY. THIS FRONT WOULD LIKELY TRACK THROUGH NORTH TEXAS ON
FRIDAY WITH TEMPERATURES AGAIN FALLING TO WELL BELOW NORMAL NEXT
WEEKEND. WE HAVE SEEN THE MODELS WAFFLE A BIT ON JUST HOW COLD
THIS AIRMASS WILL BE OVER THE LAST FEW DAYS FOR NORTH TEXAS. WHILE
THIS WILL SURELY BE ANOTHER NOTEWORTHY COLD SNAP FOR MUCH OF THE
COUNTRY...AS FAR AS NORTH TEXAS IS CONCERNED...THE MODELS ARE NOT
FORECASTING AN UPPER LEVEL PATTERN THAT WOULD RESULT IN ANY TYPE
OF RECORD BREAKING COLD HERE. AT THIS POINT I DONT SEE ANY
COMPELLING REASON TO BELIEVE THIS WILL BE ANY COLDER THAN OUR LAST
ARCTIC SPELL. THIS IS BECAUSE ALL MODELS HAVE BEEN VERY CONSISTENT
ON STRONG SURFACE LOW CYCLOGENESIS ACROSS THE PLAINS AND GREAT
LAKES WHICH WILL SERVE TO KEEP THE UPPER LEVEL LONGWAVE TROUGH
MORE PROGRESSIVE. PROGRESSIVE LONGWAVE TROUGHS DONT LET AS MUCH
COLD AIR DROP THIS FAR SOUTH AS SLOW MOVING OR STATIONARY UPPER
TROUGHS DO. ESSENTIALLY IN THIS UPPER LEVEL PATTERN...THE CORE OF
THE COLD AIR ENDS UP HEADING MORE EAST THAN SOUTH ONCE IT ARRIVES
INTO THE PLAINS AND MIDWEST.
CONCERNING WINTER PRECIP POTENTIAL...THERE IS STILL A TREMENDOUS
AMOUNT OF UNCERTAINTY WITH THE SHORTER WAVELENGTH FEATURES THAT
WOULD POSSIBLY PROVIDE THE LIFT AND MOISTURE REQUIRED FOR POST
FRONTAL WINTER PRECIP. IT WILL CERTAINLY BE COLD ENOUGH OVER NORTH
TEXAS FOR WINTER PRECIP AND LIKELY SNOW BY SATURDAY. THE KEY AT
THIS POINT IS VERY WEAK SHORTWAVE TROUGH THAT IS CURRENTLY OVER
JAPAN. THIS SYSTEM IS FORECAST TO REMAIN A RATHER INNOCUOUS POCKET
OF POTENTIAL VORTICITY FOR THE NEXT SEVERAL DAYS AS IT TRACKS
ACROSS THE PACIFIC...BUT IS FORECAST TO AMPLIFY/INTENSIFY AS IT
ARRIVES INTO THE PACIFIC NORTHWEST WEDNESDAY AND THURSDAY. THE 12Z
GFS/CANADIAN PHASE THIS ENERGY INTO THE BROADER LONGWAVE TROUGH...
AND SUGGEST ALL PRECIP WILL END BEFORE THE AIR GETS COLD ENOUGH
FOR SNOW. THE ECMWF AND SEVERAL GFS ENSEMBLE MEMBERS INDICATE
THAT THE ENERGY WITH THIS SYSTEM WILL REMAIN DETACHED FROM THE
MAIN UPPER TROUGH AND FORM INTO A CLOSED UPPER LOW WHICH TRACKS
OVER THE REGION SATURDAY. THIS SOLUTION WOULD RESULT IN A CHANCE
OF SNOW...ESPECIALLY OVER THE NORTHWEST/NORTHERN ZONES SATURDAY.
RIGHT NOW BASED ON ALL ENSEMBLE AND AVAILABLE OPERATIONAL RUNS WE
WOULD ESTIMATE THE CHANCE OF SNOW IN PART OF OUR CWA NEXT
SATURDAY AT 20 PERCENT. OF COURSE AT THIS TIME RANGE THERE IS
PLENTY OF TIME FOR MODELS TO TREND IN EITHER DIRECTION...SO WE
WILL HAVE TO WAIT AND SEE.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 39 43 29 54 35 / 20 10 0 0 0
WACO, TX 39 45 28 55 30 / 10 10 0 0 0
PARIS, TX 40 43 26 49 31 / 40 10 0 0 0
DENTON, TX 37 43 24 54 30 / 20 10 0 0 0
MCKINNEY, TX 38 42 25 52 28 / 20 10 0 0 0
DALLAS, TX 39 42 30 53 37 / 20 10 0 0 0
TERRELL, TX 40 43 27 52 30 / 30 10 0 0 0
CORSICANA, TX 42 44 28 53 34 / 20 10 0 0 0
TEMPLE, TX 40 46 29 56 30 / 5 10 0 0 0
MINERAL WELLS, TX 35 44 25 58 30 / 20 10 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
300 PM CST THU DEC 12 2013
.SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...
MID TO UPPER LEVEL CLOUDS ARE COVERING ALL OF SOUTH CENTRAL TEXAS
THIS AFTERNOON AS SOUTHWEST FLOW ALOFT PUSHES MOISTURE ACROSS THE
AREA. THESE CLOUDS WILL LINGER AROUND THROUGH FRIDAY AS AN UPPER
LEVEL TROUGH TRAVELS FROM THE DESERT SOUTHWEST INTO THE SOUTHERN
PLAINS. AT LOWER LEVELS...VISIBLE SATELLITE IMAGES ARE DEPICTING
BROKEN TO OVERCAST SKIES PUSHING TO THE NORTH-NORTHEAST ACROSS THE RIO
GRANDE VALLEY WHILE SPREADING NORTHEASTWARD TOWARD THE SAN ANTONIO
AREA. LATEST RUC SOLUTION HAS THIS LOW LEVEL CLOUD DECK SPREADING
ACROSS MOST AREAS OF SOUTH CENTRAL TEXAS BY MIDNIGHT. OVERNIGHT
LOWS WILL RANGE FROM THE MID TO UPPER 30S HILL COUNTRY TO LOWER
40S REST OF THE AREA. LATE TONIGHT INTO FRIDAY...CHANCES OF RAIN
WILL BE INCREASING AS THE UPPER LEVEL TROUGH ABOVE MENTIONED NEARS
THE SOUTHERN PLAINS. EXPECT SHOWERS TO AFFECT THE NORTHWEST AND
NORTHERN SECTIONS OF SOUTH CENTRAL TEXAS OVERNIGHT WITH SHOWERS
SPREADING EASTWARD ON FRIDAY. RAIN CHANCES WILL COME TO AN END
LATE FRIDAY AS THE UPPER TROUGH PUSHES TO THE EAST. RAINFALL
AMOUNTS WILL GENERALLY BE FROM A FEW HUNDREDTHS TO ONE QUARTER
INCH...ESPECIALLY ACROSS THE NORTHEAST PART OF THE HILL COUNTRY.
&&
.LONG TERM (SATURDAY THROUGH THURSDAY)...
A DRY COLD FRONT IS EXPECTED TO PUSH ACROSS SOUTH CENTRAL TEXAS
ON SATURDAY WITH SKIES CLEARING FROM WEST TO EAST BY THE AFTERNOON.
MODERATE NORTHWESTERLY WINDS ARE EXPECTED IN THE WAKE OF THE FRONT
WITH WIND SPEEDS DECREASING LATE SATURDAY INTO SUNDAY. SEVERAL
COOL NIGHTS ARE EXPECTED IN THE WAKE OF THE FRONTAL PASSAGE WITH
OVERNIGHT LOWS IN THE LOWER 30S OVER THE HILL COUNTRY AND MID 30S
REST OF THE AREA ON SUNDAY WITH SIMILAR LOWS MONDAY MORNING.
A NORTHWEST TO ZONAL FLOW ALOFT IS ANTICIPATED FOR MUCH OF NEXT
WEEK WITH DRY AND WARMING WEATHER CONDITIONS IN STORE THROUGH
THURSDAY OF NEXT WEEK. LATEST GFS AND ECMWF SOLUTIONS CONTINUE TO
SHOW ANOTHER ARCTIC AIRMASS ARRIVING TO THE LOCAL AREA BETWEEN
SATURDAY AND SUNDAY...DECEMBER 21 AND 22.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 39 56 44 55 33 / 10 40 20 10 -
AUSTIN BERGSTROM INTL AIRPORT 37 58 42 56 32 / 10 40 20 10 -
NEW BRAUNFELS MUNI AIRPORT 40 58 44 57 33 / 10 30 20 10 -
BURNET MUNI AIRPORT 37 56 40 52 30 / 20 40 10 - -
DEL RIO INTL AIRPORT 40 63 41 60 34 / 10 10 - 0 -
GEORGETOWN MUNI AIRPORT 37 56 42 52 31 / 20 40 20 10 -
HONDO MUNI AIRPORT 40 60 43 61 32 / 10 30 10 - -
SAN MARCOS MUNI AIRPORT 39 59 44 57 33 / 10 40 20 10 -
LA GRANGE - FAYETTE REGIONAL 41 60 47 57 33 / 10 40 30 10 -
SAN ANTONIO INTL AIRPORT 41 58 45 59 34 / 10 30 20 - -
STINSON MUNI AIRPORT 43 60 46 61 35 / 10 30 20 10 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...13
SYNOPTIC/GRIDS...17
PUBLIC SERVICE/DATA COLLECTION...33
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
530 PM CST FRI DEC 13 2013
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 205 PM CST FRI DEC 13 2013
WATER VAPOR LOOP/LATEST RUC 500MB ANALYSIS SHOWS A BROAD LONG WAVE
TROUGH ENCOMPASSING THE ENTIRE CONUS. WITHIN THIS LONG WAVE TROUGH
THERE ARE TWO MID-LEVEL SHORTWAVE TROUGHS THAT WILL EVENTUALLY
IMPACT THE AREA TONIGHT THROUGH SATURDAY EVENING. TROUGH NUMBER ONE
WAS MOVING EAST OUT OF MT/WY TOWARD THE NORTHERN PLAINS WHILE A MORE
POTENT TROUGH NUMBER TWO WAS MOVING EAST OUT OF CO/NM INTO THE
SOUTHERN PLAINS. AT THE SURFACE...THIS TRANSLATED TO AN AREA OF
CYCLOGENESIS OVER WESTERN KS WITH A WARM FRONT EXTENDING ALONG THE
IA/MO BORDER INTO CENTRAL IL. CURRENTLY...OUR LOCAL FORECAST AREA
WAS IN BETWEEN THE INFLUENCES OF THE SOUTHERN PLAINS LOW AND HIGH
PRESSURE OVER SOUTHERN MANITOBA CANADA WITH EAST WINDS AND MOSTLY
CLOUDY CONDITIONS RESULTING. TEMPERATURES THIS AFTERNOON RANGED FROM
THE TEENS ACROSS NORTH CENTRAL WI...TO THE LOWER AND MIDDLE 20S
ELSEWHERE.
WILL BE WATCHING THE SOUTHERN PLAINS AND NORTHERN PLAINS TROUGHS
CONVERGE ON THE AREA LATE TONIGHT INTO SATURDAY. NOT PARTICULARLY
STRONG DYNAMICS ASSOCIATED WITH THESE WAVES. HOWEVER...THE AREA WILL
BE IN LONG-LIVED RIGHT ENTRANCE REGION OF 300MB JET WHILE THERE IS
SOME WEAK ISENTROPIC UPGLIDE NOTED ON THE NAM 275K SURFACE.
ALSO...THERE IS A DECENT PASSING LOBE OF 700-300 PV-ADVECTION FROM
ABOUT 12Z-18Z SATURDAY. ALL THIS IS EXPECTED TO COME TOGETHER TO
PRODUCE A FAIRLY WIDESPREAD AREA OF LIGHT SNOW WITH THE PEAK
CENTERED FROM ABOUT 09Z-15Z...THEN TAPERING OFF IN THE
AFTERNOON/SATURDAY EVENING AS THE TROUGH AXIS PASSES AND SUBSIDENCE
TAKES OVER. SOME VERY LIGHT SNOW/FLURRIES WILL BE POSSIBLE THROUGH
MIDNIGHT SATURDAY NIGHT BEFORE FULL SUBSIDENCE KICKS IN...DRYING
THINGS OUT. APPEARS AT THIS TIME THERE IS THE POTENTIAL FOR 1/2 UP
TO 2 INCHES OF SNOWFALL OUT OF THIS FROM TONIGHT THROUGH SATURDAY
EVENING. TEMPERATURE-WISE... LOOK FOR LOWS TONIGHT IN THE SINGLE
DIGITS AND TEENS...HIGHS ON SATURDAY IN THE UPPER TEENS TO MIDDLE
20S...AND LOWS SATURDAY NIGHT DROPPING INTO THE SINGLE DIGITS ABOVE
AND BELOW ZERO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 205 PM CST FRI DEC 13 2013
SUNDAY LOOKS DRY AT THIS TIME BUT CLOUDS WILL BE THICKENING ONCE
AGAIN IN ADVANCE OF THE NEXT MID-LEVEL SHORTWAVE TO IMPACT THE AREA.
FOR SUNDAY NIGHT INTO MONDAY...WARM AIR ADVECTION WING OF THIS WAVE
MOVES IN WITH A GOOD CHANCE FOR LIGHT SNOW TO OVERSPREAD THE AREA.
WILL HAVE TO WATCH CLOSELY AS MODEL BUFKIT SOUNDINGS HINT AT THE
POTENTIAL FOR SOME LOSS OF ICE IN THE COLUMN. THIS COULD LEAD TO
SOME FREEZING DRIZZLE ISSUES. KEPT PRECIPITATION AS ALL SNOW FOR NOW
AFTER COORDINATION/COLLABORATION WITH OTHER OFFICES...BUT WILL
REMAIN LEARY AND KEEP A CLOSE EYE ON LATER MODEL RUNS FOR FREEZING
DRIZZLE POTENTIAL. OTHERWISE...SNOWFALL LOOKS TO BE VERY LIGHT WITH
LESS THAN AN INCH EXPECTED.
TUESDAY THROUGH WEDNESDAY LOOK TO BE DRY FOR NOW AS NORTHWEST FLOW
ALOFT PERSISTS ACROSS THE EASTERN HALF OF THE CONUS.
ECMWF/GFS COMING INTO BETTER AGREEMENT WITH THE LOW PRESSURE SYSTEM
AFFECTING THE AREA ON THURSDAY. APPEARS THERE WILL BE ENOUGH WARM
AIR DRAWN IN WITH THIS SYSTEM TO PRODUCE A RAIN/SNOW MIX FOR
PORTIONS OF THE AREA AS TEMPERATURES WARM INTO THE LOWER/MIDDLE 30S
ALONG AND SOUTH OF I-90. LOOK FOR THE PRECIPITATION TO SWITCH BACK
TO ALL SNOW AS COLD AIR SWEEPS IN BEHIND THE DEPARTING LOW THURSDAY
NIGHT.
THERE WILL BE A LINGERING CHANCE FOR LIGHT SNOW ON FRIDAY AS A
POTENT/COLD MID-LEVEL TROUGH MOVES TOWARD THE UPPER MISSISSIPPI
RIVER FROM THE NORTHERN PLAINS. OTHERWISE...MUCH COLDER TEMPERATURES
LOOK TO INVADE THE AREA WITH HIGHS DROPPING BACK INTO THE TEENS/20S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 530 PM CST FRI DEC 13 2013
DECK OF MVFR CLOUDS CONTINUES TO RESIDE JUST TO THE NORTH OF BOTH
TAF SITES. CURRENT OBSERVATIONS SUGGEST THE WESTERN EDGE OF THIS
DECK EXTENDS FROM ABOUT KRGK TO KDLL AND MAY POSSIBLY BE RETREATING
TO THE NORTHEAST AS KONA AND KBCK HAVE BOTH LOST THE MVFR CEILING.
WITH THE LOW LEVEL EAST FLOW WOULD TEND TO THINK THESE CLOUDS WILL
EVENTUALLY GET PUSHED OVER THE TAF SITES. THE 13.21Z RAP SUPPORTS
THIS IDEA WITH ITS BUFKIT SOUNDINGS SHOWING A MVFR CEILING
DEVELOPING AT BOTH TAF SITES BY 02Z-03Z. HOWEVER...THE LAMP
GUIDANCE WOULD SUGGEST IT DOES NOT COME IN UNTIL ALMOST 06Z. GIVEN
THE CLOSE PROXIMITY OF THESE CLOUDS WITH THE EAST LOW LEVEL
FLOW...DECIDED TO GO WITH AN EARLIER ARRIVAL. THE NEXT PROBLEM IS
THEN HOW LOW WILL THE VISIBILITY GET WITH THE LIGHT SNOW THAT IS
EXPECTED TO DEVELOP OVERNIGHT. THIS WILL BE IN RESPONSE TO THE A
NORTHERN STREAM SHORT WAVE THAT WILL BE APPROACHING...BUT MOST OF
ITS FORCING IS ALOFT WITH A SUBSIDENT SIGNAL IN THE 850-700MB QG
FIELDS. THE 13.15Z SREF SHOWS A HIGH PROBABILITY OF LESS THAN 3
MILES VISIBILITY IN THE LIGHT SNOW...BUT CURRENT UP STREAM
OBSERVATIONS DO NOT SUPPORT THIS. OPTED TO CONTINUE THE TRENDS
FROM THE PREVIOUS FORECAST WITH A PREVAILING MVFR VISIBILITY AND
CEILING IN THE LIGHT SNOW WITH A PERIOD OF IFR CONDITIONS
POSSIBLE. THE FORCING FROM THE SHORT WAVE TROUGH WILL MOVE OFF TO
THE EAST BY LATE MORNING TO EARLY AFTERNOON WHILE SOME WEAK QG
CONVERGENCE MAY CONTINUE IN THE 1000-850 MB LAYER. WENT BACK TO
JUST FLURRIES AS THE MAIN FORCING MOVES OFF WITH VFR VISIBILITIES
WHILE CONTINUING THE MVFR CEILING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1146 AM CST THU DEC 12 2013
.UPDATE...
ISSUED AT 1146 AM CST THU DEC 12 2013
BASED ON GOES IMAGERY...HAVE MADE SOME MINOR ADJUSTMENTS TO SKY
CLOVER TODAY WITH A CLEAR PERIOD GIVING WAY TO MORE CLOUDS IN THE
LATE AFTERNOON. FORECAST HAD TOO MUCH CLOUD.
ALSO..HAVE INCREASED TEMPERATURES 2-3F FOR AREAS OF SOUTHEAST MN
BASED ON CURRENT TEMPERATURE TRENDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST THU DEC 12 2013
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO SOUTHWEST CANADA...AND
TROUGHING OVER EASTERN CANADA INTO THE GREAT LAKES. IN THE NORTHWEST
FLOW BETWEEN THE RIDGE AND TROUGH...A SHORTWAVE WAS NOTED OVER
NORTHWEST WISCONSIN. DPVA FORCING FROM THE SHORTWAVE COMBINED WITH
ISENTROPIC LIFT ON THE 275-280K SURFACES AS SUGGESTED BY THE RAP HAS
SPREAD LIGHT SNOW ACROSS THE NORTHEAST HALF OF THE FORECAST AREA. IN
ADDITION...THE CLOUDS AND A WARM ADVECTION SOUTHWEST WIND IN THE LOW
LEVELS HAS CAUSED TEMPERATURES TO CLIMB OVERNIGHT. THE BREEZE...
HOWEVER...HAS HELD WIND CHILLS DOWN TO 10 TO 20 BELOW ZERO SOUTHWEST
OF I-94 TO 20 TO 25 BELOW ZERO TO THE NORTH. REGARDING THE WARM
ADVECTION HIGHER ABOVE THE SURFACE...FROM 00Z SOUNDINGS...850MB
TEMPS WERE AROUND -20C OVER THE FORECAST AREA COMPARED TO -7C AT
BIS AND AROUND -10C AT ABR AND OAX. FARTHER UPSTREAM...PLENTY OF
HIGH CLOUDS REFLECTING PACIFIC MOISTURE WERE STREAMING INTO NORTH
DAKOTA IN THE WAKE OF THE SHORTWAVE.
FIRST...WITH RESPECT TO THE WIND CHILL HAZARDS...WILL LET THEM
EXPIRE AT 12Z. ALTHOUGH WIND CHILLS ARE IMPROVING...THERE IS ONLY A
FEW HOURS LEFT TO THE ADVISORY...AND THEY ARE STILL CHILL AS
MENTIONED ABOVE.
ONGOING SNOW EARLY THIS MORNING REMAINS ON TRACK TO QUICKLY EXIT THE
FORECAST AREA...LIKELY BY 7 AM...AS THE SHORTWAVE HEADS OFF TO LAKE
MICHIGAN BY 12Z. OTHERWISE...THE REST OF THE SHORT TERM GENERALLY
LOOKS QUIET PRECIPITATION-WISE AS THE UPPER LEVEL FLOW BECOMES MORE
ZONAL OVER THE NORTHERN U.S.. THE 12.00Z GFS/CANADIAN AND 12.03Z
SREF ALL SHOW SOME LIGHT SNOW OR FLURRIES FALLING LATE THIS
AFTERNOON INTO EARLY THIS EVENING FROM TAYLOR COUNTY NORTHWARD. THIS
LIGHT PRECIPITATION IS ASSOCIATED WITH WEAK BUT MAINTAINED
ISENTROPIC LIFT AND MID-LEVEL FRONTOGENESIS. DECIDED TO ADD SOME LOW
CHANCES ON THE ORDER OF 20 PERCENT TO TAYLOR COUNTY. DESPITE MAINLY
DRY WEATHER FOR THE NEXT 24 HOURS...WE SHOULD SEE QUITE A BIT OF
CLOUD COVER...ESPECIALLY OVER THE NORTH HALF OF THE FORECAST AREA.
THESE CLOUDS OF THE MID/HIGH LEVEL VARIETY REFLECT BOTH THE PACIFIC
MOISTURE FLOWING IN BEHIND THE CURRENT SHORTWAVE AS WELL AS THE
GENERAL WARM ADVECTION PATTERN. ADDITIONALLY...LATE TONIGHT...THE
FORECAST AREA LIES IN THE RIGHT ENTRANCE REGION OF AN UPPER JET
STREAK OVER THE UPPER GREAT LAKES...FAVORING CLOUDS.
WARMER TEMPERATURES ARE ON TRACK TODAY AS SOUTHWEST WINDS BRING UP
WARMER AIR OUT OF NEBRASKA. THE 24 HOUR CHANGE AT 850MB IS FAIRLY
IMPRESSIVE...FROM THE -20C OBSERVED BACK AT 00Z YESTERDAY EVENING TO
-2C TO -10C FOR THIS EVENING. WE CERTAINLY WILL NOT MIX TO THESE
VALUES GIVEN TIME OF YEAR...CLOUDS AND SNOW COVER...BUT DEFINITELY
WARMER NONETHELESS. COLDEST READINGS WILL REMAIN IN THE CHIMNEY
AREA. AS THE UPPER FLOW TURNS ZONAL TONIGHT...A COLD FRONT CURRENTLY
OVER SOUTHERN SASKATCHEWAN IS PROGGED TO SLIDE SOUTH THROUGH THE
FORECAST AREA. THE COLD AIR IS SHALLOW BEHIND THIS FRONT AS MUCH OF
THE TEMPERATURE FALL TAKES PLACE AT 925MB AND BELOW. 925MB TEMPS
FALL 6C ON A NORTH TO NORTHEAST WIND...SO WE SHOULD SEE A DECENT
TEMPERATURE DROP TONIGHT DESPITE CLOUDS IN PLACE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 329 AM CST THU DEC 12 2013
FOR FRIDAY THROUGH SATURDAY...ATTENTION TURNS TO AN UPPER LOW
CURRENTLY SITTING NEAR FAR SOUTHERN CALIFORNIA. 12.00Z MODELS
REMAIN CONSISTENT ON TRACKING THIS FEATURE INTO THE CENTRAL
PLAINS ON FRIDAY...THEN UP THROUGH THE OHIO VALLEY FRIDAY NIGHT
AND SATURDAY. THIS TRACK WOULD KEEP THE BULK OF THE SYSTEMS
PRECIPITATION... INCLUDING THE DEFORMATION SHIELD...SOUTHEAST OF
THE FORECAST AREA. 12.00Z ECMWF SHOWS A COMPLETELY DRY FORECAST
FOR THE AREA. HOWEVER...THE 12.00Z GFS/CANADIAN/NAM SUGGEST
POTENTIAL FOR LIGHT SNOW THROUGH THIS ENTIRE PERIOD. ALL
INDICATIONS FROM THESE MODELS SUGGEST THE OHIO VALLEY SHORTWAVE
TROUGH IS NOT THE CAUSE FOR THE PRECIPITATION...BUT ACTUALLY 2
NORTHERN STREAM SHORTWAVE TROUGHS DIGGING DOWN THROUGH THE AREA
AND LINGERING WEAK MID LEVEL FRONTOGENESIS FROM TONIGHT. HARD TO
SAY REALLY WHAT SOLUTION WILL END UP VERIFYING...THE DRY ECMWF OR
THE WETTER GFS/CANADIAN/NAM... BUT EVEN THE WETTER SOLUTION DOES
NOT LOOK TO AMOUNT TO MUCH ACCUMULATION. CONSENSUS WARRANTS
MAINTAINING AT LEAST A 20 PERCENT CHANCE OVER TAYLOR/CLARK
COUNTIES ON FRIDAY...INCREASING CHANCES TO 30-40 PERCENT FRIDAY
NIGHT...THEN DECREASING TOWARDS 20-30 PERCENT BY SATURDAY
AFTERNOON. ALSO BELIEVE THE CHANCES ARE NEEDED AS EVEN THE ECMWF
SHOWS THE 2 NORTHERN STREAM SHORTWAVE TROUGHS. WHETHER WE GET
PRECIPITATION OR NOT...ALL MODELS AGREE ON PLENTY OF CLOUD COVER.
DESPITE THESE CLOUDS...CONSENSUS OF GUIDANCE SUGGESTS TEMPERATURES
WILL BE WARMER THAN WHAT HAS BEEN SEEN RECENTLY. SOME OF THIS IS
DUE TO SLIGHTLY WARMER AIR GETTING PULLED UP TOWARDS THE AREA
AROUND THE SYSTEM TRACKING INTO THE OHIO VALLEY.
OF THE TWO AFOREMENTIONED SHORTWAVE TROUGHS...THE SECOND ONE IS
MUCH MORE POTENT...DIGGING INTO LAKE SUPERIOR AND UPPER MICHIGAN
SATURDAY NIGHT. SOME LIGHT SNOW COULD OCCUR ACROSS AT LEAST
WISCONSIN PORTIONS OF THE AREA SATURDAY NIGHT AS THIS TROUGH DIGS
SOUTH. MORE IMPORTANTLY IS THE COLD SHOT OF AIR FOLLOWING IN ITS
WAKE...WHICH LIKE THE ONE COMING IN TONIGHT IS SHALLOW AS SEEN IN
925MB VERSUS 850MB PROGS. THE 12.00Z ECMWF IS BY FAR THE COLDEST
BRINGING 925MB TEMPS DOWN TO -13 TO -20C AT 18Z SUNDAY. HIGHS AT A
MINIMUM ARE LIKELY IN THE LOW TO MID TEENS...AND IF THE ECMWF IS
RIGHT TAYLOR COUNTY DOES NOT REACH 10 ABOVE.
LOOKING AHEAD TO NEXT WEEK...12.00Z ECMWF/GFS/CANADIAN/GFS ENSEMBLES
AGREE ON A NORTHWEST FLOW PATTERN FOR EARLY IN THE WEEK WITH
TROUGHING OVER THE GREAT LAKES. DESPITE BEING IN THE TROUGH AND
NORTHWEST FLOW...ITS ACTUALLY A WARM ADVECTION PATTERN IN THE LOW
LEVELS. THUS...LOW PRECIPITATION CHANCES ARE NEEDED...ESPECIALLY
ACROSS WISCONSIN WHERE THE FORCING IS STRONGEST. SOME HINTS THAT THE
FORCING WEAKENS ON TUESDAY...ENOUGH SO THAT CHANCES ARE ONLY INCLUDE
UP AROUND TAYLOR COUNTY. AS WE HEAD TOWARDS WEDNESDAY A POTENT
TROUGH STARTS DIGGING INTO THE PACIFIC NORTHWEST...PRODUCING ZONAL
FLOW DOWNSTREAM. THAT IS IF YOU BELIEVE THE ECMWF...BECAUSE THE GFS
DIGS A SHORTWAVE TROUGH DOWN INTO THE OHIO VALLEY. BOTH MODELS
SUGGEST DRY CONDITIONS...BUT THERE ARE MASSIVE TEMPERATURE
DIFFERENCES. GIVEN A SIMILAR SPLIT IN THE GFS ENSEMBLES...HAVE SPLIT
THE DIFFERENCE FOR NOW ON TEMPS.
FARTHER OUT...IT APPEARS AFTER A BRIEF POSSIBLE WARM UP ON WEDNESDAY
AND THURSDAY...ANOTHER BIG SURGE OF ARCTIC AIR LOOKS POISED TO DROP
DOWN INTO THE NORTH CENTRAL U.S. HEADING INTO THE FIRST OFFICIAL
WEEKEND OF WINTER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1146 AM CST THU DEC 12 2013
A WEATHER SYSTEM MOVING THROUGH NORTHERN WI AND NORTHERN MN LATER
TONIGHT AND FRIDAY WILL BRING LOWERING CLOUDS DURING THE PERIOD TO
THE TAF SITES. NO WEATHER IS EXPECTED FROUM THIS SYSTEM AT THE TAF
LOCATIONS...HOWEVER...CIGS MAY WORK TOWARD MVFR FRIDAY AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BAUMGARDT
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
534 AM CST THU DEC 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST THU DEC 12 2013
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO SOUTHWEST CANADA...AND
TROUGHING OVER EASTERN CANADA INTO THE GREAT LAKES. IN THE NORTHWEST
FLOW BETWEEN THE RIDGE AND TROUGH...A SHORTWAVE WAS NOTED OVER
NORTHWEST WISCONSIN. DPVA FORCING FROM THE SHORTWAVE COMBINED WITH
ISENTROPIC LIFT ON THE 275-280K SURFACES AS SUGGESTED BY THE RAP HAS
SPREAD LIGHT SNOW ACROSS THE NORTHEAST HALF OF THE FORECAST AREA. IN
ADDITION...THE CLOUDS AND A WARM ADVECTION SOUTHWEST WIND IN THE LOW
LEVELS HAS CAUSED TEMPERATURES TO CLIMB OVERNIGHT. THE BREEZE...
HOWEVER...HAS HELD WIND CHILLS DOWN TO 10 TO 20 BELOW ZERO SOUTHWEST
OF I-94 TO 20 TO 25 BELOW ZERO TO THE NORTH. REGARDING THE WARM
ADVECTION HIGHER ABOVE THE SURFACE...FROM 00Z SOUNDINGS...850MB
TEMPS WERE AROUND -20C OVER THE FORECAST AREA COMPARED TO -7C AT
BIS AND AROUND -10C AT ABR AND OAX. FARTHER UPSTREAM...PLENTY OF
HIGH CLOUDS REFLECTING PACIFIC MOISTURE WERE STREAMING INTO NORTH
DAKOTA IN THE WAKE OF THE SHORTWAVE.
FIRST...WITH RESPECT TO THE WIND CHILL HAZARDS...WILL LET THEM
EXPIRE AT 12Z. ALTHOUGH WIND CHILLS ARE IMPROVING...THERE IS ONLY A
FEW HOURS LEFT TO THE ADVISORY...AND THEY ARE STILL CHILL AS
MENTIONED ABOVE.
ONGOING SNOW EARLY THIS MORNING REMAINS ON TRACK TO QUICKLY EXIT THE
FORECAST AREA...LIKELY BY 7 AM...AS THE SHORTWAVE HEADS OFF TO LAKE
MICHIGAN BY 12Z. OTHERWISE...THE REST OF THE SHORT TERM GENERALLY
LOOKS QUIET PRECIPITATION-WISE AS THE UPPER LEVEL FLOW BECOMES MORE
ZONAL OVER THE NORTHERN U.S.. THE 12.00Z GFS/CANADIAN AND 12.03Z
SREF ALL SHOW SOME LIGHT SNOW OR FLURRIES FALLING LATE THIS
AFTERNOON INTO EARLY THIS EVENING FROM TAYLOR COUNTY NORTHWARD. THIS
LIGHT PRECIPITATION IS ASSOCIATED WITH WEAK BUT MAINTAINED
ISENTROPIC LIFT AND MID-LEVEL FRONTOGENESIS. DECIDED TO ADD SOME LOW
CHANCES ON THE ORDER OF 20 PERCENT TO TAYLOR COUNTY. DESPITE MAINLY
DRY WEATHER FOR THE NEXT 24 HOURS...WE SHOULD SEE QUITE A BIT OF
CLOUD COVER...ESPECIALLY OVER THE NORTH HALF OF THE FORECAST AREA.
THESE CLOUDS OF THE MID/HIGH LEVEL VARIETY REFLECT BOTH THE PACIFIC
MOISTURE FLOWING IN BEHIND THE CURRENT SHORTWAVE AS WELL AS THE
GENERAL WARM ADVECTION PATTERN. ADDITIONALLY...LATE TONIGHT...THE
FORECAST AREA LIES IN THE RIGHT ENTRANCE REGION OF AN UPPER JET
STREAK OVER THE UPPER GREAT LAKES...FAVORING CLOUDS.
WARMER TEMPERATURES ARE ON TRACK TODAY AS SOUTHWEST WINDS BRING UP
WARMER AIR OUT OF NEBRASKA. THE 24 HOUR CHANGE AT 850MB IS FAIRLY
IMPRESSIVE...FROM THE -20C OBSERVED BACK AT 00Z YESTERDAY EVENING TO
-2C TO -10C FOR THIS EVENING. WE CERTAINLY WILL NOT MIX TO THESE
VALUES GIVEN TIME OF YEAR...CLOUDS AND SNOW COVER...BUT DEFINITELY
WARMER NONETHELESS. COLDEST READINGS WILL REMAIN IN THE CHIMNEY
AREA. AS THE UPPER FLOW TURNS ZONAL TONIGHT...A COLD FRONT CURRENTLY
OVER SOUTHERN SASKATCHEWAN IS PROGGED TO SLIDE SOUTH THROUGH THE
FORECAST AREA. THE COLD AIR IS SHALLOW BEHIND THIS FRONT AS MUCH OF
THE TEMPERATURE FALL TAKES PLACE AT 925MB AND BELOW. 925MB TEMPS
FALL 6C ON A NORTH TO NORTHEAST WIND...SO WE SHOULD SEE A DECENT
TEMPERATURE DROP TONIGHT DESPITE CLOUDS IN PLACE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 329 AM CST THU DEC 12 2013
FOR FRIDAY THROUGH SATURDAY...ATTENTION TURNS TO AN UPPER LOW
CURRENTLY SITTING NEAR FAR SOUTHERN CALIFORNIA. 12.00Z MODELS
REMAIN CONSISTENT ON TRACKING THIS FEATURE INTO THE CENTRAL
PLAINS ON FRIDAY...THEN UP THROUGH THE OHIO VALLEY FRIDAY NIGHT
AND SATURDAY. THIS TRACK WOULD KEEP THE BULK OF THE SYSTEMS
PRECIPITATION... INCLUDING THE DEFORMATION SHIELD...SOUTHEAST OF
THE FORECAST AREA. 12.00Z ECMWF SHOWS A COMPLETELY DRY FORECAST
FOR THE AREA. HOWEVER...THE 12.00Z GFS/CANADIAN/NAM SUGGEST
POTENTIAL FOR LIGHT SNOW THROUGH THIS ENTIRE PERIOD. ALL
INDICATIONS FROM THESE MODELS SUGGEST THE OHIO VALLEY SHORTWAVE
TROUGH IS NOT THE CAUSE FOR THE PRECIPITATION...BUT ACTUALLY 2
NORTHERN STREAM SHORTWAVE TROUGHS DIGGING DOWN THROUGH THE AREA
AND LINGERING WEAK MID LEVEL FRONTOGENESIS FROM TONIGHT. HARD TO
SAY REALLY WHAT SOLUTION WILL END UP VERIFYING...THE DRY ECMWF OR
THE WETTER GFS/CANADIAN/NAM... BUT EVEN THE WETTER SOLUTION DOES
NOT LOOK TO AMOUNT TO MUCH ACCUMULATION. CONSENSUS WARRANTS
MAINTAINING AT LEAST A 20 PERCENT CHANCE OVER TAYLOR/CLARK
COUNTIES ON FRIDAY...INCREASING CHANCES TO 30-40 PERCENT FRIDAY
NIGHT...THEN DECREASING TOWARDS 20-30 PERCENT BY SATURDAY
AFTERNOON. ALSO BELIEVE THE CHANCES ARE NEEDED AS EVEN THE ECMWF
SHOWS THE 2 NORTHERN STREAM SHORTWAVE TROUGHS. WHETHER WE GET
PRECIPITATION OR NOT...ALL MODELS AGREE ON PLENTY OF CLOUD COVER.
DESPITE THESE CLOUDS...CONSENSUS OF GUIDANCE SUGGESTS TEMPERATURES
WILL BE WARMER THAN WHAT HAS BEEN SEEN RECENTLY. SOME OF THIS IS
DUE TO SLIGHTLY WARMER AIR GETTING PULLED UP TOWARDS THE AREA
AROUND THE SYSTEM TRACKING INTO THE OHIO VALLEY.
OF THE TWO AFOREMENTIONED SHORTWAVE TROUGHS...THE SECOND ONE IS
MUCH MORE POTENT...DIGGING INTO LAKE SUPERIOR AND UPPER MICHIGAN
SATURDAY NIGHT. SOME LIGHT SNOW COULD OCCUR ACROSS AT LEAST
WISCONSIN PORTIONS OF THE AREA SATURDAY NIGHT AS THIS TROUGH DIGS
SOUTH. MORE IMPORTANTLY IS THE COLD SHOT OF AIR FOLLOWING IN ITS
WAKE...WHICH LIKE THE ONE COMING IN TONIGHT IS SHALLOW AS SEEN IN
925MB VERSUS 850MB PROGS. THE 12.00Z ECMWF IS BY FAR THE COLDEST
BRINGING 925MB TEMPS DOWN TO -13 TO -20C AT 18Z SUNDAY. HIGHS AT A
MINIMUM ARE LIKELY IN THE LOW TO MID TEENS...AND IF THE ECMWF IS
RIGHT TAYLOR COUNTY DOES NOT REACH 10 ABOVE.
LOOKING AHEAD TO NEXT WEEK...12.00Z ECMWF/GFS/CANADIAN/GFS ENSEMBLES
AGREE ON A NORTHWEST FLOW PATTERN FOR EARLY IN THE WEEK WITH
TROUGHING OVER THE GREAT LAKES. DESPITE BEING IN THE TROUGH AND
NORTHWEST FLOW...ITS ACTUALLY A WARM ADVECTION PATTERN IN THE LOW
LEVELS. THUS...LOW PRECIPITATION CHANCES ARE NEEDED...ESPECIALLY
ACROSS WISCONSIN WHERE THE FORCING IS STRONGEST. SOME HINTS THAT THE
FORCING WEAKENS ON TUESDAY...ENOUGH SO THAT CHANCES ARE ONLY INCLUDE
UP AROUND TAYLOR COUNTY. AS WE HEAD TOWARDS WEDNESDAY A POTENT
TROUGH STARTS DIGGING INTO THE PACIFIC NORTHWEST...PRODUCING ZONAL
FLOW DOWNSTREAM. THAT IS IF YOU BELIEVE THE ECMWF...BECAUSE THE GFS
DIGS A SHORTWAVE TROUGH DOWN INTO THE OHIO VALLEY. BOTH MODELS
SUGGEST DRY CONDITIONS...BUT THERE ARE MASSIVE TEMPERATURE
DIFFERENCES. GIVEN A SIMILAR SPLIT IN THE GFS ENSEMBLES...HAVE SPLIT
THE DIFFERENCE FOR NOW ON TEMPS.
FARTHER OUT...IT APPEARS AFTER A BRIEF POSSIBLE WARM UP ON WEDNESDAY
AND THURSDAY...ANOTHER BIG SURGE OF ARCTIC AIR LOOKS POISED TO DROP
DOWN INTO THE NORTH CENTRAL U.S. HEADING INTO THE FIRST OFFICIAL
WEEKEND OF WINTER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 534 AM CST THU DEC 12 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. CIRRUS WILL
SPREAD ACROSS THE REGION TODAY AHEAD OF A WEAK STORM SYSTEM
PUSHING SOUTHEAST FROM THE NORTHERN PLAINS. THE SYSTEM WILL SLIDE
OVER NORTHERN WISCONSIN LATE THIS AFTERNOON INTO TONIGHT BUT WILL
DO LITTLE MORE THAN DROP CEILINGS INTO THE 8 TO 10 KFT RANGE AT
BOTH KRST AND KSLE. WINDS WILL BE OUT OF THE WEST/SOUTHWEST TODAY
AT AROUND 8 KTS...THEN BECOMING LIGHT LATE THIS AFTERNOON INTO
THIS EVENING. WINDS WILL SWITCH TO THE EAST EARLY FRIDAY MORNING
AS A SYSTEM DEVELOPS OVER THE CENTRAL PLAINS AND EDGES EAST INTO
THE MID MISSISSIPPI RIVER VALLEY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
329 AM CST THU DEC 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST THU DEC 12 2013
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO SOUTHWEST CANADA...AND
TROUGHING OVER EASTERN CANADA INTO THE GREAT LAKES. IN THE NORTHWEST
FLOW BETWEEN THE RIDGE AND TROUGH...A SHORTWAVE WAS NOTED OVER
NORTHWEST WISCONSIN. DPVA FORCING FROM THE SHORTWAVE COMBINED WITH
ISENTROPIC LIFT ON THE 275-280K SURFACES AS SUGGESTED BY THE RAP HAS
SPREAD LIGHT SNOW ACROSS THE NORTHEAST HALF OF THE FORECAST AREA. IN
ADDITION...THE CLOUDS AND A WARM ADVECTION SOUTHWEST WIND IN THE LOW
LEVELS HAS CAUSED TEMPERATURES TO CLIMB OVERNIGHT. THE BREEZE...
HOWEVER...HAS HELD WIND CHILLS DOWN TO 10 TO 20 BELOW ZERO SOUTHWEST
OF I-94 TO 20 TO 25 BELOW ZERO TO THE NORTH. REGARDING THE WARM
ADVECTION HIGHER ABOVE THE SURFACE...FROM 00Z SOUNDINGS...850MB
TEMPS WERE AROUND -20C OVER THE FORECAST AREA COMPARED TO -7C AT
BIS AND AROUND -10C AT ABR AND OAX. FARTHER UPSTREAM...PLENTY OF
HIGH CLOUDS REFLECTING PACIFIC MOISTURE WERE STREAMING INTO NORTH
DAKOTA IN THE WAKE OF THE SHORTWAVE.
FIRST...WITH RESPECT TO THE WIND CHILL HAZARDS...WILL LET THEM
EXPIRE AT 12Z. ALTHOUGH WIND CHILLS ARE IMPROVING...THERE IS ONLY A
FEW HOURS LEFT TO THE ADVISORY...AND THEY ARE STILL CHILL AS
MENTIONED ABOVE.
ONGOING SNOW EARLY THIS MORNING REMAINS ON TRACK TO QUICKLY EXIT THE
FORECAST AREA...LIKELY BY 7 AM...AS THE SHORTWAVE HEADS OFF TO LAKE
MICHIGAN BY 12Z. OTHERWISE...THE REST OF THE SHORT TERM GENERALLY
LOOKS QUIET PRECIPITATION-WISE AS THE UPPER LEVEL FLOW BECOMES MORE
ZONAL OVER THE NORTHERN U.S.. THE 12.00Z GFS/CANADIAN AND 12.03Z
SREF ALL SHOW SOME LIGHT SNOW OR FLURRIES FALLING LATE THIS
AFTERNOON INTO EARLY THIS EVENING FROM TAYLOR COUNTY NORTHWARD. THIS
LIGHT PRECIPITATION IS ASSOCIATED WITH WEAK BUT MAINTAINED
ISENTROPIC LIFT AND MID-LEVEL FRONTOGENESIS. DECIDED TO ADD SOME LOW
CHANCES ON THE ORDER OF 20 PERCENT TO TAYLOR COUNTY. DESPITE MAINLY
DRY WEATHER FOR THE NEXT 24 HOURS...WE SHOULD SEE QUITE A BIT OF
CLOUD COVER...ESPECIALLY OVER THE NORTH HALF OF THE FORECAST AREA.
THESE CLOUDS OF THE MID/HIGH LEVEL VARIETY REFLECT BOTH THE PACIFIC
MOISTURE FLOWING IN BEHIND THE CURRENT SHORTWAVE AS WELL AS THE
GENERAL WARM ADVECTION PATTERN. ADDITIONALLY...LATE TONIGHT...THE
FORECAST AREA LIES IN THE RIGHT ENTRANCE REGION OF AN UPPER JET
STREAK OVER THE UPPER GREAT LAKES...FAVORING CLOUDS.
WARMER TEMPERATURES ARE ON TRACK TODAY AS SOUTHWEST WINDS BRING UP
WARMER AIR OUT OF NEBRASKA. THE 24 HOUR CHANGE AT 850MB IS FAIRLY
IMPRESSIVE...FROM THE -20C OBSERVED BACK AT 00Z YESTERDAY EVENING TO
-2C TO -10C FOR THIS EVENING. WE CERTAINLY WILL NOT MIX TO THESE
VALUES GIVEN TIME OF YEAR...CLOUDS AND SNOW COVER...BUT DEFINITELY
WARMER NONETHELESS. COLDEST READINGS WILL REMAIN IN THE CHIMNEY
AREA. AS THE UPPER FLOW TURNS ZONAL TONIGHT...A COLD FRONT CURRENTLY
OVER SOUTHERN SASKATCHEWAN IS PROGGED TO SLIDE SOUTH THROUGH THE
FORECAST AREA. THE COLD AIR IS SHALLOW BEHIND THIS FRONT AS MUCH OF
THE TEMPERATURE FALL TAKES PLACE AT 925MB AND BELOW. 925MB TEMPS
FALL 6C ON A NORTH TO NORTHEAST WIND...SO WE SHOULD SEE A DECENT
TEMPERATURE DROP TONIGHT DESPITE CLOUDS IN PLACE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 329 AM CST THU DEC 12 2013
FOR FRIDAY THROUGH SATURDAY...ATTENTION TURNS TO AN UPPER LOW
CURRENTLY SITTING NEAR FAR SOUTHERN CALIFORNIA. 12.00Z MODELS
REMAIN CONSISTENT ON TRACKING THIS FEATURE INTO THE CENTRAL
PLAINS ON FRIDAY...THEN UP THROUGH THE OHIO VALLEY FRIDAY NIGHT
AND SATURDAY. THIS TRACK WOULD KEEP THE BULK OF THE SYSTEMS
PRECIPITATION... INCLUDING THE DEFORMATION SHIELD...SOUTHEAST OF
THE FORECAST AREA. 12.00Z ECMWF SHOWS A COMPLETELY DRY FORECAST
FOR THE AREA. HOWEVER...THE 12.00Z GFS/CANADIAN/NAM SUGGEST
POTENTIAL FOR LIGHT SNOW THROUGH THIS ENTIRE PERIOD. ALL
INDICATIONS FROM THESE MODELS SUGGEST THE OHIO VALLEY SHORTWAVE
TROUGH IS NOT THE CAUSE FOR THE PRECIPITATION...BUT ACTUALLY 2
NORTHERN STREAM SHORTWAVE TROUGHS DIGGING DOWN THROUGH THE AREA
AND LINGERING WEAK MID LEVEL FRONTOGENESIS FROM TONIGHT. HARD TO
SAY REALLY WHAT SOLUTION WILL END UP VERIFYING...THE DRY ECMWF OR
THE WETTER GFS/CANADIAN/NAM... BUT EVEN THE WETTER SOLUTION DOES
NOT LOOK TO AMOUNT TO MUCH ACCUMULATION. CONSENSUS WARRANTS
MAINTAINING AT LEAST A 20 PERCENT CHANCE OVER TAYLOR/CLARK
COUNTIES ON FRIDAY...INCREASING CHANCES TO 30-40 PERCENT FRIDAY
NIGHT...THEN DECREASING TOWARDS 20-30 PERCENT BY SATURDAY
AFTERNOON. ALSO BELIEVE THE CHANCES ARE NEEDED AS EVEN THE ECMWF
SHOWS THE 2 NORTHERN STREAM SHORTWAVE TROUGHS. WHETHER WE GET
PRECIPITATION OR NOT...ALL MODELS AGREE ON PLENTY OF CLOUD COVER.
DESPITE THESE CLOUDS...CONSENSUS OF GUIDANCE SUGGESTS TEMPERATURES
WILL BE WARMER THAN WHAT HAS BEEN SEEN RECENTLY. SOME OF THIS IS
DUE TO SLIGHTLY WARMER AIR GETTING PULLED UP TOWARDS THE AREA
AROUND THE SYSTEM TRACKING INTO THE OHIO VALLEY.
OF THE TWO AFOREMENTIONED SHORTWAVE TROUGHS...THE SECOND ONE IS
MUCH MORE POTENT...DIGGING INTO LAKE SUPERIOR AND UPPER MICHIGAN
SATURDAY NIGHT. SOME LIGHT SNOW COULD OCCUR ACROSS AT LEAST
WISCONSIN PORTIONS OF THE AREA SATURDAY NIGHT AS THIS TROUGH DIGS
SOUTH. MORE IMPORTANTLY IS THE COLD SHOT OF AIR FOLLOWING IN ITS
WAKE...WHICH LIKE THE ONE COMING IN TONIGHT IS SHALLOW AS SEEN IN
925MB VERSUS 850MB PROGS. THE 12.00Z ECMWF IS BY FAR THE COLDEST
BRINGING 925MB TEMPS DOWN TO -13 TO -20C AT 18Z SUNDAY. HIGHS AT A
MINIMUM ARE LIKELY IN THE LOW TO MID TEENS...AND IF THE ECMWF IS
RIGHT TAYLOR COUNTY DOES NOT REACH 10 ABOVE.
LOOKING AHEAD TO NEXT WEEK...12.00Z ECMWF/GFS/CANADIAN/GFS ENSEMBLES
AGREE ON A NORTHWEST FLOW PATTERN FOR EARLY IN THE WEEK WITH
TROUGHING OVER THE GREAT LAKES. DESPITE BEING IN THE TROUGH AND
NORTHWEST FLOW...ITS ACTUALLY A WARM ADVECTION PATTERN IN THE LOW
LEVELS. THUS...LOW PRECIPITATION CHANCES ARE NEEDED...ESPECIALLY
ACROSS WISCONSIN WHERE THE FORCING IS STRONGEST. SOME HINTS THAT THE
FORCING WEAKENS ON TUESDAY...ENOUGH SO THAT CHANCES ARE ONLY INCLUDE
UP AROUND TAYLOR COUNTY. AS WE HEAD TOWARDS WEDNESDAY A POTENT
TROUGH STARTS DIGGING INTO THE PACIFIC NORTHWEST...PRODUCING ZONAL
FLOW DOWNSTREAM. THAT IS IF YOU BELIEVE THE ECMWF...BECAUSE THE GFS
DIGS A SHORTWAVE TROUGH DOWN INTO THE OHIO VALLEY. BOTH MODELS
SUGGEST DRY CONDITIONS...BUT THERE ARE MASSIVE TEMPERATURE
DIFFERENCES. GIVEN A SIMILAR SPLIT IN THE GFS ENSEMBLES...HAVE SPLIT
THE DIFFERENCE FOR NOW ON TEMPS.
FARTHER OUT...IT APPEARS AFTER A BRIEF POSSIBLE WARM UP ON WEDNESDAY
AND THURSDAY...ANOTHER BIG SURGE OF ARCTIC AIR LOOKS POISED TO DROP
DOWN INTO THE NORTH CENTRAL U.S. HEADING INTO THE FIRST OFFICIAL
WEEKEND OF WINTER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1109 PM CST WED DEC 11 2013
WEAK AREA OF LOW PRESSURE OVER EASTERN NORTH DAKOTA WILL MOVE
RAPIDLY SOUTHEAST OVERNIGHT. A BAND OF LIGHT SNOW AHEAD OF THE LOW
IS PRESENTLY EXPECTED TO PRIMARILY MISS BOTH TAF SITES. COULD SEE
A FEW SNOWFLAKES AS IT GOES BY...BUT NOT ENOUGH TO REDUCE THE
VISIBILITY VERY MUCH IF AT ALL AND HAVE TAKEN THE MVFR VISIBILITY
RESTRICTIONS OUT OF BOTH TAF SITES. CEILINGS UP STREAM SOUTH OF
WHERE THE SNOW IS FALLING HAVE REMAINED VFR AND REFLECTED THIS
TREND IN BOTH TAFS AS WELL. ONCE THE SNOW BAND MOVES
PAST...MAINLY JUST HIGH LEVEL CLOUDS EXPECTED TO BE OVER THE
REGION FOR A GOOD SHARE OF THE DAY. THE NEXT WEAK SHORT WAVE
TROUGH WILL START TO APPROACH THURSDAY AFTERNOON AND IS EXPECTED
TO SPREAD A MID LEVEL DECK OF VFR CLOUDS ACROSS THE AREA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR WIZ017-
029-032>034-041>044-053>055-061.
MN...WIND CHILL ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR MNZ079-
086>088-094>096.
IA...WIND CHILL ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
706 PM MST FRI DEC 13 2013
.UPDATE...
ISSUED AT 703 PM MST FRI DEC 13 2013
GETTING SOME RETURNS ON RADAR ASSOCIATED WITH THE BACKDOOR COLD
FRONT PUSHING INTO THE NORTHERN PANHANDLE. CHADRON REPORTING SOME
LIGHT SNOW UP THERE AND RADAR SHOWING RETURNS ALL THE WAY DOWN TO
NEAR TORRINGTON. WENT AHEAD AND ADDED SOME SMALL POPS IN THE
FORECAST FOR THIS AREA THROUGH 06Z. AFTER THAT TIME...IT LOOKS
LIKE THE COLDER CLOUD TOPS SHOULD BE EAST INTO CENTRAL NEBRASKA. UPDATES
HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 243 PM MST FRI DEC 13 2013
QUIET WEATHER EXPECTED THIS WEEKEND WITH NORTHWEST FLOW ALOFT
RESULTING IN NEAR NORMAL TEMPERATURES OR SLIGHTLY BELOW
TEMPERATURES ACROSS THE AREA. DRY WEATHER IS EXPECTED OUTSIDE OF
THE MOUNTAINS THIS WEEKEND AS HIGH PRESSURE ALOFT ATTEMPTS TO
NUDGE EAST INTO THE CENTRAL ROCKIES. A WEAK UPPER LEVEL TROUGH IS
CURRENTLY MOVING ACROSS WYOMING AND WESTERN COLORADO TODAY...BUT
THE MAIN IMPACT FROM THIS DISTURBANCE SEEMS TO BE JUST MID TO HIGH
LEVEL CLOUDINESS AND SLIGHTLY COOLER TEMPERATURES. WINDS HAVE
DECREASED ACROSS THE WIND PRONE AREAS EARLY TODAY AND ARE EXPECTED
TO REMAIN BETWEEN 10 TO 20 KNOTS TONIGHT BEFORE INCREASING ONCE
AGAIN THIS WEEKEND.
FOR SATURDAY AND SUNDAY...UPPER LEVEL RIDGE WILL DRIFT EASTWARD
INTO THE ROCKYS AS HIGH PRESSURE BUILDS NEAR THE SURFACE WEST OF
THE CONTINENTAL DIVIDE. THIS 1040 MB SURFACE HIGH WILL BUILD OVER
WESTERN WYOMING AND WESTERN COLORADO THROUGH SUNDAY...INCREASING
THE PRESSURE GRADIENT ALONG THE FRONT RANGE. EXPECT WEST TO
SOUTHWEST WINDS TO INCREASE IN THE WIND PRONE AREAS ON SATURDAY
WITH STRONG WINDS POSSIBLE OVER THESE AREAS SATURDAY NIGHT AND
SUNDAY AS MODELS INDICATE GUSTS AROUND 55 MPH ARE POSSIBLE. IN
OTHER AREAS...IT WILL BE BREEZY OR WINDY WITH GUSTS UP TO 40 MPH
POSSIBLE. OUTSIDE OF A SOME LIGHT MOUNTAIN SNOWFALL...CONDITIONS
ARE EXPECTED TO REMAIN DRY WITH INTERVALS OF MID TO HIGH CLOUDS
MOVING ACROSS THE AREA.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 243 PM MST FRI DEC 13 2013
THIS PORTION OF THE FORECAST WILL START OFF CONTINUED MILD AND
WINDYWITH A BIG CHANGE TO MUCH COLDER AND SNOWY WEATHER LATE NEXT
WEEK.
FAST NORTHWEST FLOW ALOFT WILL BE OVER THE REGION MONDAY THROUGH
TUESDAY NIGHT AS A POLAR VORTEX WILL BE OVER EASTERN CANADA. THE
300 MB JET WILL BE OVER THE AREA WILL BE MARGINALLY FAVORABLE. A
SURFACE FRONT BACKS ACROSS THE EAST PART OF THE CWA MONDAY NIGHT
AND WILL BE STATIONARY ALONG THE LARAMIE RANGE THROUGH TUESDAY.
THAT BOUNDARY...A WEAKER SURFACE PRESSURE GRADIENT AND LACK OF
SURFACE PRESSURE FALLS TO OUR NORTH DURING THAT TIME MAY HINDER
THE STRONG WINDS FROM MATERIALIZING. HEIGHTS ALOFT RISE OVER THE
ROCKIES TUESDAY NIGHT AND WEDNESDAY AND A SURFACE TROUGH WILL BE
LOCATED NEAR THE EASTERN WYOMING BORDER. TEMPERATURES WILL WARM
SOME EACH DAY WITH WEDNESDAY BEING THE WARMEST DAY IN THIS PERIOD.
A RIDGE ALOFT DEVELOPS OVER THE EASTERN PACIFIC BY MIDWEEK AND
WILL HELP DEEPEN A SHORTWAVE TROUGH AS IT MOVES OVER THE WESTERN
U.S. WEDNESDAY AND WEDNESDAY NIGHT. THE PROGRESSIVE FEATURE MOVES
ACROSS THE CWA THURSDAY AFTERNOON AND THURSDAY NIGHT WITH MODELS
TRENDING FASTER. AN ASSOCIATED COLD FRONT WILL MOVE SOUTH AND
ACROSS THE CWA THURSDAY AND THURSDAY EVENING. MODEL TRENDS HAVE
BEEN FOR A FASTER MOVEMENT SOUTH OF THE FRONT AND THE ECMWF REMAINS
FASTER THAN THE GFS. SNOW WILL DEVELOP BEHIND THE FRONT AS MID
LEVEL FRONTOGENESIS AND 300 MB JET DYNAMICS ALONG WITH THE SURFACE
FORCING WILL PROVIDE THE SYNOPTIC LIFT. CONDITIONS IMPROVE FROM
NORTH TO SOUTH ON FRIDAY AS SURFACE HIGH PRESSURE BUILDS INTO THE
AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY AFTERNOON)
ISSUED AT 423 PM MST FRI DEC 13 2013
VERY TRICKY FORECAST FOR THE 00Z TAFS. GETTING SOME LOW STARTUS UP
IN WEASTERN SOUTH DAKOTA THAT COULD MAKE IT INTO THE NORTHERN
PANHANDLE AND EAST CENTRAL WYOMING THIS EVENING. SREF AND NAM
GUIDANCE SUGGEST CEILINGS DROPPING TO IFR AT KCDR AND KAIA.
RELIABLE HRRR FORECAST THOUGH HAS THESE TWO AIRPORTS VFR. WILL GO
WITH MVFR AT THESE LOCATIONS FOR NOW AND AMEND IF NEEDED.
CONFIDENCE NOT HIGH EITHER WAY. WINDS DO SHIFT WESTERLY...WHICH
WOULD BE MORE INDICATIVE OF VFR CONDITIONS. CONFIDENCE BETTER
AFTER 06Z THAT AIRPORTS WILL GO VFR.
&&
.FIRE WEATHER...
ISSUED AT 243 PM MST FRI DEC 13 2013
NO FIRE WEATHER CONCERNS ARE EXPECTED THROUGH THE WEEKEND AND INTO
EARLY NEXT WEEK. MINIMUM RELATIVE HUMIDITIES WILL GENERALLY RANGE
FROM 30 TO 50 PERCENT WITH SOME SNOWPACK REMAINING OVER THE AREA.
GUSTY WESTERLY WINDS MAY BECOME STRONG IN THE WIND PRONE AREAS OF
SOUTHEAST WYOMING BY SATURDAY MORNING WITH STRONG WINDS POSSIBLE
EACH DAY EARLY NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...CLAYCOMB
SHORT TERM...TJT
LONG TERM...WEILAND
AVIATION...CLAYCOMB
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
429 PM MST FRI DEC 13 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 243 PM MST FRI DEC 13 2013
QUIET WEATHER EXPECTED THIS WEEKEND WITH NORTHWEST FLOW ALOFT
RESULTING IN NEAR NORMAL TEMPERATURES OR SLIGHTLY BELOW
TEMPERATURES ACROSS THE AREA. DRY WEATHER IS EXPECTED OUTSIDE OF
THE MOUNTAINS THIS WEEKEND AS HIGH PRESSURE ALOFT ATTEMPTS TO
NUDGE EAST INTO THE CENTRAL ROCKIES. A WEAK UPPER LEVEL TROUGH IS
CURRENTLY MOVING ACROSS WYOMING AND WESTERN COLORADO TODAY...BUT
THE MAIN IMPACT FROM THIS DISTURBANCE SEEMS TO BE JUST MID TO HIGH
LEVEL CLOUDINESS AND SLIGHTLY COOLER TEMPERATURES. WINDS HAVE
DECREASED ACROSS THE WIND PRONE AREAS EARLY TODAY AND ARE EXPECTED
TO REMAIN BETWEEN 10 TO 20 KNOTS TONIGHT BEFORE INCREASING ONCE
AGAIN THIS WEEKEND.
FOR SATURDAY AND SUNDAY...UPPER LEVEL RIDGE WILL DRIFT EASTWARD
INTO THE ROCKYS AS HIGH PRESSURE BUILDS NEAR THE SURFACE WEST OF
THE CONTINENTAL DIVIDE. THIS 1040 MB SURFACE HIGH WILL BUILD OVER
WESTERN WYOMING AND WESTERN COLORADO THROUGH SUNDAY...INCREASING
THE PRESSURE GRADIENT ALONG THE FRONT RANGE. EXPECT WEST TO
SOUTHWEST WINDS TO INCREASE IN THE WIND PRONE AREAS ON SATURDAY
WITH STRONG WINDS POSSIBLE OVER THESE AREAS SATURDAY NIGHT AND
SUNDAY AS MODELS INDICATE GUSTS AROUND 55 MPH ARE POSSIBLE. IN
OTHER AREAS...IT WILL BE BREEZY OR WINDY WITH GUSTS UP TO 40 MPH
POSSIBLE. OUTSIDE OF A SOME LIGHT MOUNTAIN SNOWFALL...CONDITIONS
ARE EXPECTED TO REMAIN DRY WITH INTERVALS OF MID TO HIGH CLOUDS
MOVING ACROSS THE AREA.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 243 PM MST FRI DEC 13 2013
THIS PORTION OF THE FORECAST WILL START OFF CONTINUED MILD AND
WINDYWITH A BIG CHANGE TO MUCH COLDER AND SNOWY WEATHER LATE NEXT
WEEK.
FAST NORTHWEST FLOW ALOFT WILL BE OVER THE REGION MONDAY THROUGH
TUESDAY NIGHT AS A POLAR VORTEX WILL BE OVER EASTERN CANADA. THE
300 MB JET WILL BE OVER THE AREA WILL BE MARGINALLY FAVORABLE. A
SURFACE FRONT BACKS ACROSS THE EAST PART OF THE CWA MONDAY NIGHT
AND WILL BE STATIONARY ALONG THE LARAMIE RANGE THROUGH TUESDAY.
THAT BOUNDARY...A WEAKER SURFACE PRESSURE GRADIENT AND LACK OF
SURFACE PRESSURE FALLS TO OUR NORTH DURING THAT TIME MAY HINDER
THE STRONG WINDS FROM MATERIALIZING. HEIGHTS ALOFT RISE OVER THE
ROCKIES TUESDAY NIGHT AND WEDNESDAY AND A SURFACE TROUGH WILL BE
LOCATED NEAR THE EASTERN WYOMING BORDER. TEMPERATURES WILL WARM
SOME EACH DAY WITH WEDNESDAY BEING THE WARMEST DAY IN THIS PERIOD.
A RIDGE ALOFT DEVELOPS OVER THE EASTERN PACIFIC BY MIDWEEK AND
WILL HELP DEEPEN A SHORTWAVE TROUGH AS IT MOVES OVER THE WESTERN
U.S. WEDNESDAY AND WEDNESDAY NIGHT. THE PROGRESSIVE FEATURE MOVES
ACROSS THE CWA THURSDAY AFTERNOON AND THURSDAY NIGHT WITH MODELS
TRENDING FASTER. AN ASSOCIATED COLD FRONT WILL MOVE SOUTH AND
ACROSS THE CWA THURSDAY AND THURSDAY EVENING. MODEL TRENDS HAVE
BEEN FOR A FASTER MOVEMENT SOUTH OF THE FRONT AND THE ECMWF REMAINS
FASTER THAN THE GFS. SNOW WILL DEVELOP BEHIND THE FRONT AS MID
LEVEL FRONTOGENESIS AND 300 MB JET DYNAMICS ALONG WITH THE SURFACE
FORCING WILL PROVIDE THE SYNOPTIC LIFT. CONDITIONS IMPROVE FROM
NORTH TO SOUTH ON FRIDAY AS SURFACE HIGH PRESSURE BUILDS INTO THE
AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY AFTERNOON)
ISSUED AT 423 PM MST FRI DEC 13 2013
VERY TRICKY FORECAST FOR THE 00Z TAFS. GETTING SOME LOW STARTUS UP
IN WEASTERN SOUTH DAKOTA THAT COULD MAKE IT INTO THE NORTHERN
PANHANDLE AND EAST CENTRAL WYOMING THIS EVENING. SREF AND NAM
GUIDANCE SUGGEST CEILINGS DROPPING TO IFR AT KCDR AND KAIA.
RELIABLE HRRR FORECAST THOUGH HAS THESE TWO AIRPORTS VFR. WILL GO
WITH MVFR AT THESE LOCATIONS FOR NOW AND AMEND IF NEEDED.
CONFIDENCE NOT HIGH EITHER WAY. WINDS DO SHIFT WESTERLY...WHICH
WOULD BE MORE INDICATIVE OF VFR CONDITIONS. CONFIDENCE BETTER
AFTER 06Z THAT AIRPORTS WILL GO VFR.
&&
.FIRE WEATHER...
ISSUED AT 243 PM MST FRI DEC 13 2013
NO FIRE WEATHER CONCERNS ARE EXPECTED THROUGH THE WEEKEND AND INTO
EARLY NEXT WEEK. MINIMUM RELATIVE HUMIDITIES WILL GENERALLY RANGE
FROM 30 TO 50 PERCENT WITH SOME SNOWPACK REMAINING OVER THE AREA.
GUSTY WESTERLY WINDS MAY BECOME STRONG IN THE WIND PRONE AREAS OF
SOUTHEAST WYOMING BY SATURDAY MORNING WITH STRONG WINDS POSSIBLE
EACH DAY EARLY NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...WEILAND
AVIATION...CLAYCOMB
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS ALBANY NY
348 AM EST SAT DEC 14 2013
.SYNOPSIS...
ARCTIC HIGH PRESSURE SITUATED ACROSS THE SAINT LAWRENCE VALLEY
HAS USHERED IN A VERY COLD AND DRY AIR MASS INTO THE REGION.
MEANWHILE A COMPLEX WINTER STORM IS TAKING SHAPE ACROSS THE
CENTER OF THE NATION AND WILL TRACK TOWARD NEW ENGLAND TONIGHT.
THIS WILL SPREAD AN ACCUMULATING SNOW ACROSS MOST OF THE REGION.
THIS STORM WILL DEPART BY SUNDAY AFTERNOON WITH SLOW IMPROVEMENTS
TO OUR WEATHER EXPECTED.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
H2O VAPOR LOOP REVEALS OUR MAIN INGREDIENT FOR OUR WINTER STORM
WAS TRACKING ACROSS NORTHERN ARKANSAS AND SOUTHERN MISSOURI AND
TRACKING NORTHEAST TOWARD THE OHIO VALLEY. A STRENGTHENING UPPER
JET IS UNDERWAY ACROSS THE SOUTHERN CONUS PER SATELLITE WIND
ESTIMATES AND HOURLY RUC ANALYSIS WITH ANOTHER UPPER JET SEGMENT
ACROSS THE UPPER GREAT LAKES REGION. THIS NORTHERN PORTION OF THE
JET IS EXPECTED TO REMAIN CYCLONIC IN NATURE WHICH SUGGESTS THIS
UPPER LOW MAY TRACK A LITTLE FURTHER WEST AND HANGING ONTO THE
INITIAL SURFACE LOW LONGER BEFORE THE TRANSFER OCCURS OFF THE MID
ATLANTIC COAST. BROAD ISENTROPIC LIFT IN ADVANCE OF THESE FEATURES
WAS UNDERWAY ACROSS THE NY/PA BORDER AS BAROCLINICITY WAS
INCREASING JUST NORTH OF THE ARCTIC BOUNDARY. PER EXPERIMENTAL
REFLECTIVITY FORECASTS FROM A VARIETY OF MESOSCALE MODELS...ALONG
WITH THE DRY AIR IN PLACE...IT MAY TAKE MOST OF THE MORNING TO
SATURATE THE LOWER LEVELS FOR SNOW TO REACH THE GROUND /VIRGA/
SOUTH OF I90 AS LOW LEVEL AGEOSTROPIC FLOW REMAINS IN PLACE
/MAGNITUDE IS NOT THAT STRONG BUT IS VERY PERSISTENT/.
THEREFORE...WE WILL SLOW DOWN THE ONSET OF PRECIP IN THE GRIDS
FROM SOUTH TO NORTH TODAY. AD FOR HIGH TEMPERATURES...BLENDED
APPROACH OF THE MOS GUIDANCE WAS UTILIZED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
...WINTER STORM WARNING IN EFFECT FOR THE ENTIRE REGION...
PREVIOUS DISCUSSIONS HAVE DONE AN EXCELLENT JOB WITH THE
METEOROLOGICAL PARAMETERS SETTING UP FOR THIS FIRST WIDESPREAD
SIGNIFICANT WINTER EVENT FOR THE REGION. 00Z GUIDANCE ALONG WITH THE
RECENT ARRIVAL OF THE 06Z NAM CONTINUE TO INCREASE QPF AMOUNTS
ALONG WITH ENHANCED FGEN BANDS SEEN IN THE H850-H700 LAYER PER
PREVIOUS CSTAR RESEARCH. THESE BANDS ARE PROGGED TO BE A LITTLE
FURTHER NORTH AND PER COORDINATION FROM WPC AND SURROUNDING
WFOS...WE WILL UPGRADE THE ADVISORY AREA AND EXTEND THE WARNING
ACROSS THE ENTIRE CWFA. IT WILL BE CLOSE PER THE DEFINITION OF 7"
IN 12HRS OR 9" IN 24HRS BUT WITH A HIGH IMPACT WIDESPREAD EVENT
THE WARNING WAS EXPANDED. AS WARM ADVECTION OCCURS IN THE THERMAL
PROFILES...SOME OF THE PRECIP ACROSS DUTCHESS AND LITCHFIELD
COUNTIES WILL MIX WITH SLEET AND FREEZING RAIN LATE TONIGHT. ICE
ACCUMULATIONS UP TO TWO TENTHS OF AN INCH ARE POSSIBLE BEFORE THE
WARM AIR AT THE SURFACE ARRIVES TO RESULT IN A CHANGEOVER TO
MAINLY RAIN/RAIN SHOWERS LATER SUNDAY MORNING. SO TEMPERATURES
WILL BE STEADY TO SLOWLY RISING OVERNIGHT AS WE WILL SHOW A NON-
DIURNAL TEMPERATURE TREND OVERNIGHT.
THE OTHER COMPLICATED FACTOR TO THIS WILL BE TRANSITIONING
SNOW TO LIQUID RATIOS AS WE SHOULD INITIALLY BE RATHER HIGH WITH
15:1 RATIO THEN GRADUALLY DROPPING TOWARD CLIMATOLOGY OF 12:1 FOR
MOST OF THE REGION AND EVENTUALLY TOWARD 10:1 TOWARD SUNRISE
SUNDAY. THE CROSS SECTIONS NOW REVEAL WE WILL INDEED SEE THE BEST
LIFT OCCUR IN THE BEST DENDRITIC SNOW GROWTH REGION WHICH ALONG
WITH FGEN BANDS TO ENHANCE SNOWFALL RATES. IN FACT...D-THETA/DZ
SUGGESTS THE SMALL POTENTIAL FOR CONVECTIVE ELEMENTS BETWEEN 06Z-
12Z SUNDAY AND AS THE SECONDARY LOW DEVELOPS OFF THE NJ
COAST...THE DUCT FUNCTION POINTS TOWARD THE POTENTIAL FOR A
GRAVITY WAVE/S/.
PRECIP SHADOW IS INDEED STILL PLAUSIBLE TOO AS LOW-MID LEVEL EAST-
SOUTHEAST WINDS INCREASE SUGGESTING PRECIP SHADOW DOWNWIND OF THE
BERKS-TACONICS AND THE GREENS INTO PORTIONS OF WASHINGTON COUNTY.
THIS STORM DEEPENS SUNDAY AS IT TRACKS THROUGH THE SOUTHERN
PORTIONS OF THE GULF OF MAINE WITH DEFORMATION SNOW AXIS ACROSS
PORTIONS OF THE DACKS. WIND GUSTS WILL LIKELY INCREASE TOO WHICH
WILL RESULT IN SOME BLOWING AND DRIFTING OF THE SNOW.
FURTHERMORE...WIND CHILLS WILL LIKELY DIP WELL BELOW ZERO ACROSS
THE DACKS AS WE MAY NEED HEADLINES FOR THIS IN FUTURE FORECASTS.
SNOW WILL TAPER OFF THROUGH THE DAYLIGHT HOURS SUNDAY WITH SOME
LAKE RESPONSE SUNDAY NIGHT INTO PORTIONS OF THE DACKS...WESTERN
MOHAWK VALLEY AND CATSKILLS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
BEHIND THE DEPARTING WINTER STORM...HIGH PRESSURE WILL MOVE OVER
THE REGION FOR MONDAY. WITH A COLD NW FLOW IN PLACE...MAX TEMPS
WILL BE BELOW NORMAL...WITH TEENS TO MID 20S ACROSS THE REGION.
VERY COLD TEMP WILL CONTINUE INTO MONDAY NIGHT WITH SINGLE DIGITS
OVER MUCH OF THE AREA. SOME BELOW ZERO READINGS WILL OCCUR ACROSS
THE ADIRONDACKS AND GREEN MOUNTAINS.
CLOUDS WILL BEGIN TO INCREASE LATE MONDAY NIGHT...WITH A SLIGHT CHC
FOR SOME SNOW SHOWERS...AS A CLIPPER SYSTEM BEGINS TO APPROACH FROM
THE GREAT LAKES. THIS WEAK SYSTEM WILL BE QUITE MOISTURE STARVED.
STILL...THERE IS A CHANCE FOR SOME LIGHT SNOW ACROSS THE REGION FOR
TUESDAY INTO TUESDAY NIGHT AS THIS SYSTEM TRACKS ACROSS THE AREA.
ANY QPF LOOKS RATHER LIGHT...AND SNOWFALL WILL ONLY BE AN INCH OR
TWO FOR MOST PLACES. MAX TEMPS WILL CONTINUE TO BE CHILLY ON TUESDAY
WITH 20S OVER MUCH OF THE AREA...AND TEENS TO LOW 20S FOR TUESDAY
NIGHT.
SOME LAKE EFFECT SNOW WILL OCCUR ACROSS THE WESTERN ADIRONDACKS AND
WESTERN MOHAWK VALLEY BEHIND THIS CLIPPER SYSTEM FOR WED INTO WED
NIGHT. OTHERWISE...IT LOOKS DRY OVER MUCH OF THE AREA. TEMPS ON WED
WILL BE A LITTLE WARMER THAN RECENT DAYS...WITH MID 20S TO MID 30S.
HOWEVER...A REINFORCING SHOT OF COLD AIR LOOKS TO ARRIVE ON WED
NIGHT...WITH TEENS FOR THE AREA...AND TEMPS BACK INTO THE 20S FOR
THURSDAY.
THIS COLD SHOT LOOKS TO BE SHORT LIVED...AS HIGH PRESSURE QUICKLY
PASSES OVER THE AREA...AND THE PATTERN BEGINS TO SHIFT SOMEWHAT.
WHILE IT WILL BE DRY FOR THURSDAY...THE OVERALL FLOW STARTS TO
BECOME MORE OUT OF THE SW BOTH AT THE LOW LEVELS AND ALOFT. THIS
WILL TRANSPORT MUCH WARMER AND MORE MOIST AIR INTO THE REGION FOR
THE LATE WEEK PERIOD. MAX TEMPS LOOK TO REACH INTO THE 40S FOR
VALLEY AREAS BY FRIDAY. ALTHOUGH IT/S STILL RATHER FAR OUT IN
TIME...AN APPROACHING SLOW MOVING FRONTAL BOUNDARY LOOKS TO BRING A
PERIOD OF PLAIN RAIN TO THE REGION FOR LATE IN THE WEEK AND INTO THE
WEEKEND ACROSS THE ENTIRE REGION...EVEN THE HIGHER TERRAIN
AREAS...WITH A RETURN TO ABOVE NORMAL TEMPS EXPECTED INTO THE
WEEKEND.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
CLOUDS WILL BE INCREASING THROUGH THE REMAINDER OF THE NIGHT...AS
A STORM SYSTEM ORGANIZES OVER THE SOUTHEAST AND MOISTURE CONTINUES
TO SPREAD NORTHEAST. FLYING CONDITIONS WILL GENERALLY BE VFR FOR
THE VALLEY TERMINALS WITH BKN-OVC CIGS OF 3500-6000 FT THROUGH THE
REMAINDER OF THE OVERNIGHT HOURS. HOWEVER...SOME BKN CIGS AROUND
1500-2000 FT ARE POSSIBLE FOR KPSF...ALLOWING FOR A PERIOD OF MVFR
CONDITIONS OVER THE BERKSHIRES. IT SHOULD REMAIN DRY THROUGH THE
REMAINDER OF THE OVERNIGHT AS WELL...WITH A LIGHT N-NE WIND AROUND
5 KTS.
AS THE STORM SYSTEM STRENGTHENS AND MOVES ACROSS THE
SOUTHEAST...LIGHT SNOW WILL DEVELOP ACROSS SOUTHERN AREAS DURING THE
MORNING HOURS AND SLOWLY SPREAD NORTHWARD. SNOW LOOKS TO BEGIN AT
KPOU AS EARLY AS 15Z...BUT WILL TAKE UNTIL 18Z TO GET GOING AT KALB.
INITIALLY...THE DRY AIRMASS IN PLACE WILL ONLY ALLOW FOR LIGHT SNOW
AND MVFR CONDITIONS. AFTER A FEW HOURS...ALL TERMINALS LOOK TO SEE
IFR CONDITIONS BY THE MID TO LATE AFTN HOURS WITH SNOW PICKING UP IN
INTENSITY. BY SATURDAY EVENING...LIFR CONDITIONS ARE POSSIBLE AS
WELL...WHEN THE SNOW WILL BE FALLING ITS HARDEST AND VV WILL BE
QUITE LIMITED. DURING THE DAY SATURDAY...WINDS WILL GENERALLY BE
FROM THE NE AND WILL BE STRENGTHENING TO 5-10 KTS BY SAT EVENING.
OUTLOOK...
SUNDAY: HIGH OPERATIONAL IMPACT. DEFINITE SN.
SUNDAY NIGHT-MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
TUESDAY-TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX
&&
.HYDROLOGY...
NO HYDRO RELATED CONCERNS ARE EXPECTED THE NEXT 5 DAYS.
QPF FROM THIS UPCOMING EVENT WILL RANGE FROM ONE HALF INCH TO ONE
AND ONE QUARTER OF AN INCH WITH THOSE HIGHER VALUES ACROSS THE
TERRAIN INTO THE CATSKILLS...SOUTHERN GREENS AND PORTIONS OF THE
DACKS. MOST OF THIS WILL FALL IN THE FORM OF SNOW WITH THE
EXCEPTION ACROSS DUTCHESS AND LITCHFIELD COUNTIES WHERE A WINTRY
MIXTURE AND PERHAPS A PERIOD OF RAIN MAY RESULT LATE SATURDAY
NIGHT INTO SUNDAY MORNING. ANY LIQUID PRECIP SHOULD RESULT WITHIN
BANK RISES.
THEREAFTER...TEMPS WILL CONTINUE TO BE BELOW NORMAL AND ICE WILL
CONTINUE TO FORM AND THICKEN ON AREA RIVERS...STREAMS AND
PARTICULARLY LAKES THROUGH EARLY NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING FROM 8 AM THIS MORNING TO 1 PM EST SUNDAY
FOR CTZ001-013.
NY...WINTER STORM WARNING FROM 8 AM THIS MORNING TO 1 PM EST SUNDAY
FOR NYZ032-033-038>043-047>054-058>061-063>066-082>084.
MA...WINTER STORM WARNING FROM 8 AM THIS MORNING TO 1 PM EST SUNDAY
FOR MAZ001-025.
VT...WINTER STORM WARNING FROM 8 AM THIS MORNING TO 1 PM EST SUNDAY
FOR VTZ013>015.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...FRUGIS
HYDROLOGY...BGM
FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
345 AM EST SAT DEC 14 2013
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A UPPER LEVEL PATTERN IN
THE PROCESS OF TRANSITIONING FROM A GENERALLY ZONAL PATTERN OVER THE
EASTERN CONUS TO A PATTERN DOMINATED BY LONGWAVE TROUGHING. THE
LEADING IMPULSES IN THIS TRANSITION IS A STRONG SHORTWAVE EJECTING
EASTWARD FROM THE MID/LOWER MS VALLEY EARLY THIS MORNING TOWARD THE
TN VALLEY AND CAROLINAS. A SECONDARY SHORTWAVE AND IMPULSE IS
FOLLOWING CLOSE BEHIND OVER THE SOUTHERN PLAINS. THIS FIRST
SHORTWAVE WILL PASS WELL TO OUR NORTH DURING THE LATER MORNING
HOURS...AND THEN THE SECOND IMPULSE WILL MAKE A CLOSER PASS ALONG
THE NORTHERN GULF COAST TONIGHT AND SUNDAY. WV IMAGERY SHOWS LOTS OF
UPPER LEVEL MOISTURE STREAMING EASTWARD AHEAD OF THESE SYSTEMS
ACROSS THE GULF OF MEXICO AND FLORIDA PENINSULA. WV IMAGERY ALSO
SHOWS STRONG SUBSIDENCE/DRYING IN THE WAKE OF THIS LEAD
IMPULSE...HOWEVER THIS SUBSIDENCE WILL BYPASS WELL TO OUR NORTH AND
WE WILL NEED TO WAIT UNTIL THE WAKE OF THE SECONDARY SHORTWAVE LATER
SUNDAY AND SUNDAY NIGHT TO FINALLY CLEAR OUR SKIES ONCE AGAIN.
AT THE SURFACE...1028MB HIGH PRESSURE IS LETTING UP ITS INFLUENCE ON
THE FL PENINSULA THIS MORNING AS IT SLIDES EASTWARD INTO THE WESTERN
ATLANTIC IN RESPONSE TO A WAVE OF LOW PRESSURE MOVING EASTWARD FROM
THE LOWER MS VALLEY. A COLD FRONT CURRENTLY EXTENDS SOUTHWARD FROM
THIS FEATURE INTO THE WESTERN GULF OF MEXICO AND WILL BE MOVING
EASTWARD ACROSS THE GULF THROUGH THE DAY. SEEING A MUCH WARMER EARLY
MORNING THAN 24 HOURS AGO WITH MOST LOCATIONS HOLDING IN THE 50S AND
60S AS EAST AND SOUTHEASTERLY LOW LEVEL FLOW CONTINUES TO ADVECT
ATLANTIC MOISTURE ACROSS THE REGION.
&&
.SHORT TERM (TODAY THROUGH MONDAY)...
TODAY...FORECAST PHILOSOPHY HAS NOT CHANGED MUCH IN TERMS OF THE
SENSIBLE WEATHER AND TIMING OF THE FRONT AND FORCING MECHANISM
THROUGH THE NEXT 24 HOURS. AS THE LEAD SHORTWAVE PIVOTS
NORTHEASTWARD THROUGH THE DAY IT WILL DRAW THE SURFACE LOW
REFLECTION TO THE NORTHEAST AS WELL. THIS SURFACE FEATURE SHOULD
REACH THE EASTERN CAROLINAS AROUND SUNDOWN THIS EVENING WITH THE
COLD FRONT TRAILING BACK THROUGH GA TO THE FL PANHANDLE AND
NORTH-CENTRAL GULF. INITIAL "BATCH" OF DEEP LAYER QG-FORCING MISSES
THE REGION TO THE NORTH...AND THE SECOND ROUND OF FORCING AHEAD OF
THE SECOND SHORTWAVE DOES NOT BEGIN TO ARRIVE OVER OUR NORTHERN
ZONES UNTIL LATE TODAY AND THIS EVENING. THIS SYNOPTIC FORCING IS
ALSO NOT COMPLIMENTED BY ANY DECENT RRQ JET DYNAMICS UNTIL THIS
EVENING AND OVERNIGHT. WITH THE LOW LEVEL FOCUS OF THE FRONT MAINLY
TO OUR WEST ALL DAY AND THE LATE ARRIVAL OF THE UPPER FORCING...
STILL EXPECT MUCH OF THE FORECAST AREA TO SEE A GENERALLY DRY DAY.
DO BRING SCATTERED SHOWERS INTO THE NORTHERN NATURE COAST ZONES
AFTER 1-2PM...BUT DO NOT RAISE RAIN CHANCES TO LIKELY UNTIL AFTER
4-5PM. RAIN CHANCES WILL QUICKLY DECREASE SOUTHWARD TO THE I-4
CORRIDOR DURING THE LATER AFTERNOON HOURS...AND JUST HAVE ISOLATED
SHOWERS IN THE FORECAST FOR THE EARLY EVENING AROUND TAMPA BAY. FAR
REMOVED FROM THE FORCING LATER TODAY...AREAS SOUTH OF TAMPA BAY SHOW
A 10% POP OR LESS. IT WILL BE VERY WARM DECEMBER DAY WITHIN THE
THERMAL RIDGE AHEAD OF THE FRONT. THIS THERMAL RIDGE COMBINED WITH
DECENT DIURNAL MIXING WILL ALLOW MANY SPOTS TO REACH THE LOWER
80S...AND EVEN SOME MIDDLE 80S FOR THE SOUTHERN ZONES. BIGGER
QUESTION ON TEMPS WILL BE NORTH OF TAMPA BAY WHERE CLOUDS WILL
THICKEN/LOWER SOONER.
TONIGHT...SECONDARY SHORTWAVE QUICKLY HELPS TO EVOLVE/DEEPEN THE
LONGWAVE TROUGH OVER THE EASTERN CONUS TONIGHT...AND THE APPROACH OF
THIS ENERGY TO THE ATLANTIC COAST IS PROGGED TO RESULT IN RAPID
CYCLOGENESIS ALONG THE MID-ATLANTIC/NEW ENGLAND BAROCLINIC ZONE.
GFS/ECMWF STILL BOTH SHOW A DECENT SWATH OF QG-FORCING OVERSPREADING
THE NORTHERN HALF OF THE PENINSULA THIS EVENING AND OVERNIGHT...BUT
WITH TIME THE MAIN ENERGY WILL BEGIN TO TRANSLATE NORTHWARD TOWARD
THE DEEPENING SYSTEM OFF THE MID-ATLANTIC COAST. THE COLD FRONT IS
NOT THE FASTEST OF MOVING FEATURES AND TAKES MOST OF THE OVERNIGHT
TO REACH LEVY COUNTY AND THE NORTHERN MARINE ZONES. WITH THE MAIN
LOW LEVEL AND UPPER FORCING OVER THE NORTHERN PENINSULA...WILL SHOW
A FAIRLY TIGHT POP GRADIENT FROM CHANCE 40-55% POPS ALONG THE I-4
CORRIDOR TO CATEGORICAL 80-90% POPS UP TOWARD CITRUS/LEVY COUNTY.
FURTHER SOUTH FROM I-4...RAIN CHANCES DIMINISH QUICKLY AND LOOKING
FOR A MAINLY DRY OVERNIGHT FOR PLACES LIKE PUNTA GORDA AND FORT
MYERS OVER INTO HIGHLANDS COUNTY. 35-40KT LOW LEVEL JET MAY RESULT
IN A FEW STRONGER WIND GUSTS FOR LEVY COUNTY ASSOCIATED WITH ANY
STORMS...BUT THE OVERALL THREAT FOR SEVERE WEATHER APPEARS MARGINAL.
DEEP SOUTHWEST FLOW AHEAD OF THE FRONT WILL KEEP IT A WARM DECEMBER
NIGHT WITH LOW TEMPS FAILING TO FALL OUT OF THE MIDDLE AND UPPER
60S.
SUNDAY/SUNDAY NIGHT...
COLD FRONT BECOMES INCREASINGLY STRETCHED AS THE LOW NEAR NEW
ENGLAND DEEPENS AND QUICKLY MOVES NORTHEAST THROUGH THE DAY. THIS IS
A COMMON OCCURRENCE FOR US DURING THE COLD SEASON AND GENERALLY
MEANS THE CONVECTION AHEAD OF THE FRONT BECOMES LESS ORGANIZED WITH
TIME AS THE LOW LEVEL FOCUS DIMINISHES. THIS WILL HAPPEN HERE...BUT
WITH AT LEAST SOME WEAK LINGERING DEEP LAYER FORCING FOR
ASCENT...FEEL KEEPING CHANCE POPS IN THE FORECAST FOR ALL ZONES IN
THE MORNING IS APPROPRIATE...BUT WILL REMOVE THUNDER MENTION. AS THE
FRONT SLIPS SOUTH OF I-4 DURING THE AFTERNOON WILL REMOVE POPS FOR
THE TAMPA BAY AND NATURE COAST ZONES...AND THEN REMOVE ALL RAIN
CHANCES FURTHER SOUTH BY SUNDOWN SUNDAY EVENING. SKIES WILL ALSO
CLEAR FROM NORTH TO SOUTH DURING THE SECOND HALF OF SUNDAY AND
SUNDAY NIGHT. A COLDER AND MUCH DRIER AIRMASS WILL ARRIVE SUNDAY
NIGHT IN THE WAKE OF THE FRONT. IN GENERAL MOS GUIDANCE IS TOO COLD
ON THESE ADVECTION NIGHTS DIRECTLY BEHIND A FRONT...AND HAVE RAISED
A MAV/MET BLEND BY SEVERAL DEGREES FOR THE CURRENT LOW TEMPERATURE
FORECAST. AFTER THE ADJUSTMENT WE ARE LEFT WITH UPPER 30S AROUND
CHIEFLAND...RANGING DOWN TO AROUND 50 FOR I-4...AND MIDDLE/UPPER 50S
FOR FORT MYERS.
MONDAY...THE FIRST DAY OF THE NEW WORK WEEK LOOKS TO BE A
PLEASANT...SUNNY AND SEASONABLY COOL DAY AS HIGH PRESSURE BUILDS
EAST ALONG THE NORTHERN GULF COAST AND SUBSIDENCE EXPANDS OVERHEAD.
ENJOY YOUR SATURDAY!
&&
.LONG TERM (MONDAY NIGHT THROUGH NEXT FRIDAY)...
COOLER AND DRIER HIGH PRESSURE FROM THE NORTHERN GULF REGION WILL BE
IN PLACE ACROSS THE AREA KEEPING A GENERALLY N/NE FLOW IN PLACE
THROUGH TUESDAY. THE HIGH PRESSURE CENTER THEN SLOWLY SHIFTS TO THE
NORTHEAST ACROSS THE SOUTHEASTERN STATES TUESDAY NIGHT THROUGH
THURSDAY SHIFTING WINDS TO THE NE AND EAST ALLOWING MOISTURE AND
TEMPERATURES TO MODERATE. THE HIGH CENTER SHIFTS OFFSHORE OVER THE
WEST ATLANTIC FOR THURSDAY NIGHT AND FRIDAY WITH WINDS SHIFTING TO
THE E/SE AND A SLIGHT CHANCE OF RAIN POSSIBLE WITH THE INCREASED
MOISTURE FOR FRIDAY AFTERNOON MAINLY ACROSS THE SOUTH. TEMPERATURES
WILL BEGIN BELOW NORMAL FOR MONDAY NIGHT...THEN NEAR NORMAL TUESDAY
THROUGH WEDNESDAY NIGHT...AND RISING ABOVE NORMAL THROUGH THE REST
OF THE PERIOD.
&&
.AVIATION...
MVFR CEILINGS ARE EXPECTED TO DEVELOP ACROSS THE AREA OVER THE NEXT
COUPLE OF HOURS BEFORE SUNRISE WITH SOME PATCHY FOG ALSO POSSIBLE
MAINLY AT THE KLAL AND KPGD TERMINALS. CONDITIONS SHOULD LIFT BY 15Z
WITH VFR THEN EXPECTED THROUGH THE REST OF THE PERIOD. A COUPLE OF
SHOWERS WILL BE POSSIBLE IN THE LATE AFTERNOON/EARLY EVENING ACROSS
THE NORTHERN TERMINALS...BUT CHANCES ARE CURRENTLY TOO LOW TO
INCLUDE IN THE TAF.
&&
.MARINE...
HIGH PRESSURE MOVES AWAY FROM THE REGION AS A COLD FRONT APPROACHES
FROM THE WEST LATER TODAY AND TONIGHT. CAUTIONARY LEVEL WINDS AWAY
FROM SHORE TODAY WILL SHIFT TO MARINE ZONES MAINLY NORTH OF TARPON
SPRINGS BY TONIGHT. THE COLD FRONT WILL PUSH NORTHWEST TO SOUTHEAST
ACROSS THE EASTERN GULF ON SUNDAY WITH A WINDS SHIFT FROM SOUTHWEST
TO NORTHWEST AND NORTH. A PERIOD OF CAUTIONARY TO LOW END ADVISORY
LEVEL WINDS FROM THE NORTH IS ANTICIPATED FOR LATER SUNDAY INTO
MONDAY. SHOWERS AND THUNDERSTORMS WILL BECOME NUMEROUS TO WIDESPREAD
IN NATURE LATER TODAY INTO TONIGHT FROM TARPON SPRINGS NORTHWARD AND
SCATTERED IN NATURE FURTHER SOUTH. SHOWERS WILL CLEAR FROM NORTH TO
SOUTH ON SUNDAY WITH THE FRONTAL PASSAGE.
&&
.FIRE WEATHER...
ABUNDANT LOW LEVEL MOISTURE AHEAD OF AN APPROACHING COLD FRONT WILL
KEEP RELATIVE HUMIDITY VALUES WELL ABOVE CRITICAL LEVELS TODAY
DESPITE UNSEASONABLY WARM TEMPERATURES. WINDS WILL BE SOMEWHAT GUSTY
FROM THE SOUTHEAST AND SOUTH THROUGH THE DAY WITH MODERATE TO HIGH
DISPERSION INDICES. A COLD FRONT WILL SHIFT SOUTH ACROSS THE REGION
WITH A WIND SHIFT TO THE NORTHWEST IN ITS WAKE. THE MAIN ARRIVAL OF
DRIER IS NOT EXPECTED UNTIL SUNDAY NIGHT AND MONDAY AND NO FIRE
WEATHER CONCERNS ARE ANTICIPATED FOR SUNDAY. WITH THE DRIER AIR IN
PLACE BY MONDAY...RELATIVE HUMIDITY VALUES ARE CURRENTLY ANTICIPATED
TO BRIEFLY REACH CRITICAL LEVELS FOR MUCH OF THE AREA
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 81 69 76 52 / 20 60 50 0
FMY 83 69 82 59 / 10 20 40 10
GIF 82 67 77 50 / 20 40 50 0
SRQ 80 69 76 55 / 10 40 50 0
BKV 82 67 74 46 / 30 60 50 0
SPG 80 69 74 56 / 20 50 50 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WEATHER...MROCZKA
LONG TERM/AVIATION...COLSON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1207 AM CST SAT DEC 14 2013
.DISCUSSION...
830 PM CST
NO BIG UPDATES TO GOING FORECAST WITH ALSO NO CHANGES TO CURRENT
HEADLINES IN PLACE.
LONGWAVE TROUGH CONTINUES TO SHIFT EAST THROUGH THE CENTRAL
CONUS...WITH SEVERAL LEAD WAVES LIFTING NORTHEAST OUT AHEAD OF IT.
ASSOCIATED FORCING AS WELL AS A GOOD WAA PUSH ALLOWED FOR LIGHT TO
MODERATE SNOW TO QUICKLY MOVE INTO AREAS SOUTH OF I-80 EARLY THIS
EVENING. HIGH AMOUNTS OF MOISTURE WERE PRESENT ON THE 00Z ILX
RAOB...WITH 0.74 INCH PWAT AND 4G/KG MIXING RATIO AT 700MB.
LOW/MID LEVEL CONVERGENCE OWING TO MID/LOW LEVEL BAROCLINIC ZONE
STRETCHED ACROSS NORTH CENTRAL ILLINOIS HAS ALSO AIDED IN THE
DEVELOPMENT OF SEVERAL SMALLER SCALE FEATURES OVER THE LAST HOUR.
THE VISIBILITY HAS GENERALLY STAYED IN THE 1-3SM RANGE...WHILE
FALLING UNDER ONE MILE IN THESE SMALLER HEAVIER BANDS. ALTHOUGH
THESE SMALLER FEATURES WILL LIKELY REMAIN OVER THE NEXT SEVERAL
HOURS...THEY HAVE REMAINED TRANSIENT WITH LOCATIONS ONLY OBSERVING
BRIEF PERIODS OF THIS HEAVIER SNOW.
EXPECT THIS LIGHT TO MODERATE SNOW TO SLOWLY LIFT NORTH WITH THE
I-88 CORRIDOR LIKELY OBSERVING SNOWFALL BY THE 930 PM CST TIME
FRAME. ALTHOUGH STRONGEST WAA APPEARS TO SHIFT TO THE EAST OF THE
CWA OVER THE NEXT SEVERAL HOURS...BROAD SCALE LIFT AS WELL AS
INCREASE IN LOW LEVEL FRONTOGENESIS IS EXPECTED TO HELP PERSIST
LIGHT/MODERATE SNOW AND EVEN PROVIDE BRIEF PERIODS OF HEAVIER
SNOW. THE STRONGEST MESOSCALE FORCING WILL PERSIST TONIGHT AND
REMAIN IN THE ADVISORY AND WARNING AREAS TONIGHT INTO SATURDAY
MORNING. HAD DEBATED ADDING LIVINGSTON/KANKAKEE/LAKE IN/PORTER
COUNTY IN THE WARNING...WITH THIS ANTICIPATED STRONGER FORCING.
ALTHOUGH...WITH ONLY AN ADDITIONAL INCH OR TWO TO THE GOING
TOTALS...HAVE DECIDED TO LEAVE THE ADVISORY GOING AND INSTEAD
INCREASE THE SNOW RANGE TO 4-7 INCHES. REST OF THE SNOW TOTALS IN
THE HEADLINES STILL APPEAR TO BE ON TRACK...WITH 5 TO 8 INCHES
STILL LIKELY IN THE WARNING AREA.
CONTINUE TO MONITOR A SEPARATE AREA OF DEVELOPING SNOW ACROSS
SOUTHERN WISCONSIN AND FAR NORTHERN ILLINOIS. OUTSIDE OF THE LAKE
EFFECT/ENHANCEMENT EXPECTED ACROSS THIS AREA...LATEST GUIDANCE
CONTINUES TO INDICATE ANOTHER AREA OF BETTER FRONTOGENITICAL
FORCING ACROSS SOUTHERN WISCONSIN. THIS FORCING COULD ACT TO
SLIGHTLY ENHANCE TOTALS MORE TOWARDS THE ILLINOIS/WISCONSIN
BORDER...WITH MAYBE MORE 1-3 INCHES COULD BE OBSERVED BY TOMORROW
MORNING. LAKE EFFECT/ENHANCEMENT FOR FAR NORTHEAST ILLINOIS HAS
SHOWN INCREASING TRENDS WITH LATEST GUIDANCE. ALTHOUGH NOT OVERLY
LARGE...THIS WAS ENOUGH TO INCREASE SNOW TOTALS SLIGHTLY. LOW
LEVEL CONVERGENCE INCREASES TOWARDS EARLY SATURDAY MORNING...AND
POSSIBLY LINGERS INTO SATURDAY AFTERNOON AS BOUNDARY LAYER FLOW
SLOWLY SHIFTS. WITH THIS POSSIBLY PROVIDING AN EXTENDED PERIOD OF
LIGHT SNOW...HAVE INCREASED SNOW TOTALS MORE TOWARDS 1-3 IN LAKE
IL...BUT HAVE STILL LEFT OUT OF THE ADVISORY AT THIS TIME.
ALTHOUGH AN ISOLATED 4 INCH REPORT CANNOT BE RULED OUT IN THIS
AREA...WAS NOT ENOUGH TO INCLUDE IN THE HEADLINE. ONCE AGAIN...THE
EXTENDED NATURE OF THIS LIGHT LAKE EFFECT SNOW COULD WARRANT
HIGHER TOTALS IN LAKE COUNTY IL AND POSSIBLY HEADLINE CHANGES
SATURDAY MORNING.
RODRIGUEZ
//PREV DISCUSSION...
319 PM CST
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...
NOT MUCH HAS CHANGED WITH THE CURRENT THINKING FOR TONIGHT AND
SATURDAY REGARDING SNOWFALL AMOUNTS AND PLACEMENT. THE CURRENT
WATER VAPOR IMAGERY CONTINUES TO INDICATE A DECENT DISTURBANCE
NEAR THE TEXAS PANHANDLE EARLY THIS AFTERNOON...WITH SEVERAL LEAD
DISTURBANCES ACROSS OK AND INTO WESTERN MO. PROFILER AND VWP DATA
ACROSS THE SOUTHERN PLAINS AND MID MISSISSIPPI VALLEY INDICATES
THAT AROUND 30KT OF SOUTHWESTERLY FLOW AROUND 850 MB HAS DEVELOPED
IN ASSOCIATION WITH THIS SYSTEM. THIS IS ALLOWING FOR SOME DECENT
MOISTURE TRANSPORT AND ISENTROPIC ASCENT ACROSS THE MISSOURI AND
WEST CENTRAL ILLINOIS THIS AFTERNOON. THIS HAS PRODUCED A GOOD
AREA OF PRECIPITATION ACROSS MISSOURI...ESPECIALLY ALONG THE
LEADING EDGE OF THE BETTER MOISTURE TRANSPORT.
I EXPECT THIS AREA OF PRECIP TO CONTINUE TO MOVE NORTHWARD AND TO
OVERSPREAD MOST AREAS ALONG AND SOUTH OF INTERSTATE 80 THROUGH THE
EVENING AS THE BETTER MOISTURE GETS DRAWN NORTHWARD IN ASSOCIATION
WITH THE APPROACHING SOUTHERN STREAM SYSTEM. IT APPEARS LIKELY THAT
A BAND OF MODERATE TO HEAVY SNOW WILL SET UP THIS EVENING ACROSS MY
SOUTHERN COUNTIES...IN ASSOCIATION WITH A DEVELOPING BAND OF
FRONTOGENESIS. THE ENHANCED FORCING FOR ASCENT WITHIN THE
FRONTOGENETIC CIRCULATION WILL ALLOW FOR SOME DECENT ASCENT WITHIN
THE DENDRITIC GROWTH ZONE. THIS ALONG WITH THE FACT THAT STEEP LAPSE
RATES AND -EPV EXITS WITHIN AND ABOVE THIS ZONE ALSO SUGGESTS THAT
THEIR WILL BE SOME FAIRLY EFFICIENT SNOWFALL PRODUCTION WITHIN THIS
BAND OF SNOW. WITH THIS IN MIND...IT APPEARS THAT SNOWFALL RATES
COULD APPROACH 1 INCH PER HOUR FOR A COUPLE HOUR PERIOD THIS
EVENING...ESPECIALLY TO THE SOUTH OF INTERSTATE 80 WITHIN AND NEAR
THE CURRENT WINTER STORM WARNING.
A SECOND AREA OF SNOW WILL BE FAVORED...MAINLY ACROSS SOUTHERN
WISCONSIN THIS EVENING AS A SECONDARY AXIS OF FRONTOGENESIS DEVELOPS
ALONG A BAROCLINIC RIBBON...AND COMBINES WITH INCREASING FLOW AND LOW
LEVEL CONVERGENCE OFF OF LAKE MICHIGAN. HOWEVER...MOST HIGH RES
GUIDANCE CONTINUES TO FAVOR AREAS NORTH OF THE ILLINOIS BOARDER.
THEREFORE...IT APPEARS MOST OF NORTHERN ILLINOIS WILL REMAIN SNOW
FREE...THROUGH AT LEAST MID TO LATE EVENING.
THE SNOW SHOULD BEGIN TO SPREAD NORTHWARD BY LATE THIS EVENING...AND
BEGIN IMPACTING MOST OF NORTHERN ILLINOIS BY OR SHORTLY AFTER
MIDNIGHT AS THE SURFACE INVERTED TROUGH BECOMES ORIENTED NORTH TO
SOUTH ACROSS THE AREA OVERNIGHT. THE SNOW WILL CONTINUE INTO
SATURDAY AS SOME LARGER SCALE SUPPORT FOR ASCENT OVERSPREADS THE
AREA IN ASSOCIATION WITH THE APPROACHING NORTHERN STREAM SHORT WAVE.
THIS COULD EVEN LEAD TO A BIT IN AN UPTICK TO THE SNOWFALL
INTENSITY...PARTICULARLY ACROSS EASTERN ILLINOIS AND NORTHWESTERN
INDIANA...WHERE MID LEVEL DEFORMATION WILL CONTINUE IN ASSOCIATION
WITH THE MID LEVEL CIRCULATION. THE SNOW WILL GRADUALLY END ACROSS
NORTHERN ILLINOIS AS THE FLOW TURNS NORTHWESTERLY. SOME LINGERING
LAKE EFFECT SNOW SHOWERS ARE POSSIBLE ACROSS NORTHWESTERN INDIANA
INTO SATURDAY EVENING.
THERE ARE SOME POSSIBILITIES FOR SOME LAKE ENHANCEMENT FOR AREAS
NEAR THE LAKE LATE TONIGHT AND INTO SATURDAY AS THE FLOW TURNS EAST
NORTHEASTWARD. HOWEVER...THERMODYNAMICS OVER THE LAKE DO NOT APPEAR
TO BE VERY FAVORABLE FOR ANY SIGNIFICANT LAKE ENHANCEMENT POTENTIAL.
DELTA T`S LOOK TO REMAIN AROUND 12 DEGREES CELSIUS AND EQUILIBRIUM
LEVELS NEVER APPEAR TO REACH INTO THE DENDRITIC GROWTH ZONE.
SO...OVERALL...IT STILL APPEARS SNOWFALL AMOUNTS WILL RANGE FROM
ABOUT 5 TO 8 INCHES ACROSS THE WARNING AREA...3 TO 6 INCHES IN THE
ADVISORY AREAS...AND 2 TO 3 INCHES AROUND NORTHEASTERN
ILLINOIS...AND AN INCH OR LESS ACROSS NORTH CENTRAL ILLINOIS.
ONCE THE SNOW ENDS...THE NORTHWESTERLY FLOW WILL ALLOW COLDER AIR
TO SPILL BACK ACROSS THE REGION SETTING UP ANOTHER COLD SUNDAY
MORNING.
KJB
MEDIUM-LONG RANGE...SUNDAY THROUGH NEXT FRIDAY...
HIGHLIGHTS OF THE MEDIUM-LONG RANGE FORECAST PERIOD ARE CONTINUED
NORTHWEST UPPER FLOW WITH A PARADE OF WEAK CLIPPER SYSTEMS INTO
MID-WEEK...THEN A SHIFT TOWARD SOUTHWEST FLOW ALOFT MID/LATE NEXT
WEEK AS UPPER RIDGE BUILDS ACROSS THE EASTERN PACIFIC AND GULF OF
ALASKA AND INDUCES DOWNSTREAM LONG WAVE TROUGH ACROSS WESTERN NORTH
AMERICA. THIS WILL SUPPORT A TRANSITION FROM BELOW NORMAL TEMPS
SUN-WED...WITH THE POTENTIAL FOR A BRIEF WARM-UP THURS-EARLY FRI
AHEAD OF WESTERN TROUGH.
SUNDAY THROUGH WEDNESDAY...
MID-LEVEL SHORT WAVE TROUGH AXIS ASSOCIATED WITH EARLY WEEKEND
WINTER STORM WILL BE WELL EAST OF THE REGION BY SUNDAY MORNING.
MID/UPPER LEVEL LOW OVER DEVELOPS OVER ONTARIO AND THE NORTHERN
LAKES HOWEVER...WITH REGION OF ENHANCED NORTHWEST FLOW ALOFT FROM
THE NORTHERN PLAINS TO THE MIDWEST. SEVERAL MINOR AMPLITUDE RIPPLES
ARE INDICATED IN MODEL GUIDANCE WHICH PROPAGATE ALONG LOW LEVEL
BAROCLINIC ZONE WHICH STRETCHES NORTHWEST-SOUTHEAST ACROSS THE
REGION. SOME TIMING DIFFERENCES WITH THE MORE SUBTLE DISTURBANCES
BETWEEN MODELS...THOUGH IT APPEARS A WEAK WAVE WILL TRAVERSE THE
AREA SUNDAY WITH A SOMEWHAT BETTER DEFINED VORT MOVING OVER THE AREA
SUNDAY NIGHT AND EARLY MONDAY. FORECAST SOUNDINGS AND TIME/HEIGHT
DEPICTIONS INDICATE GENERALLY DRY MOISTURE PROFILES...WITH ONLY A
POCKET OF DEEPER MID-LEVEL MOISTURE SUNDAY NIGHT-EARLY MONDAY WITH
ISENTROPIC FORCING AHEAD OF THE STRONGER WAVE. THUS THE BEST
POTENTIAL FOR A LITTLE LIGHT SNOW APPEARS BE SUNDAY NIGHT...THOUGH
WITH LITTLE ACCUMULATION EXPECTED (A DUSTING TO PERHAPS A HALF INCH)
AS LIFT APPEARS GENERALLY WEAK AND WELL BELOW THE DENDRITIC GROWTH
ZONE. WEAK ASCENT LINGERS INTO MONDAY...ESPECIALLY ACROSS THE
NORTHEAST/EAST PARTS OF THE CWA WITH THE LEFT EXIT REGION OF THE
UPPER JET STREAK HELPING TO MAINTAIN SOME LARGE SCALE SUPPORT DURING
THE DAY. A MORE AMPLIFIED SHORT WAVE IS PROGGED TO DIG ACROSS THE
WESTERN GREAT LAKES REGION ON TUESDAY...THOUGH THE BEST WARM
ADVECTION AND ISENTROPIC UPGLIDE APPEARS TO REMAIN JUST TO THE
NORTH/NORTHEAST OF THE CWA...THOUGH A REINFORCING PUSH OF COLDER AIR
DOES ARRIVE TUESDAY NIGHT WITH A COLD FRONT.
COLDEST CONDITIONS LOOK TO OCCUR SUNDAY BEHIND THE EARLY WEEKEND
WINTER STORM...WITH HIGHS IN THE TEENS AND LOWS IN THE SINGLE DIGITS
TO AROUND 10 ABOVE. SOME MODERATION OCCURS MON-TUE WITH THE WEAK BUT
NEARLY PERSISTENT WARM ADVECTION ASSOCIATED WITH THE AFOREMENTIONED
CLIPPERS. A LITTLE COOLER TUESDAY NIGHT-WEDNESDAY BEHIND TUESDAY
NIGHTS COLD FRONT.
AS INDICATED ABOVE...DEVELOPING UPPER RIDGING OVER THE EAST PACIFIC
AND TROUGH INDUCEMENT OVER THE WESTERN CONUS WEDNESDAY-THURSDAY
RESULTS IN SURFACE LOW PRESSURE DEVELOPMENT OVER THE PLAINS BY EARLY
THURSDAY. FAIRLY DECENT MODEL AGREEMENT IN THIS LOW DEEPENING AND
LIFTING NORTHEAST ACROSS MINNESOTA AND THE NORTHERN GREAT LAKES
THURSDAY AND THURSDAY NIGHT...PLACING WFO LOT CWA IN THE WARM SECTOR
AS WARM FRONT LIFTS NORTH. SHALLOW COLD SURFACE LAYER MAY RESULT IN
A LITTLE MIXED PRECIPITATION THURSDAY MORNING ESPECIALLY NORTH AS
WARMING OCCURS MORE VIGOROUSLY ALOFT...THOUGH GFS/ECMWF RUNS
INDICATE THAT LOW LEVELS WARM ENOUGH TO PRODUCE MAINLY RAIN BY
THURSDAY EVENING/NIGHT. SOME TIMING DIFFERENCES DO ARISE WITH THE
NEW 12Z ECMWF (THE 00Z RUN WAS IN BETTER AGREEMENT WITH THE 00/12Z
GFS AND ENSEMBLE MEMBERS)...WITH THE ECMWF FASTER WITH THE LOW
LIFTING ACROSS THE NORTHERN LAKES EARLY FRIDAY AND BRINGING THE
TRAILING COLD FRONT THROUGH FASTER. CONTINUE TO FAVOR A SLIGHTLY
SLOWER SOLUTION SIMILAR TO THE 00Z EC/12Z GFS AND GEFS RUNS. THIS
WOULD SUPPORT TEMPS POTENTIALLY WARMING INTO THE 35-40 F RANGE
THURSDAY AND POTENTIALLY INTO THE 40S/EVEN 50 ACROSS THE SOUTHEAST
FRIDAY PRIOR TO COLD FRONTAL PASSAGE. PRECIP POTENTIAL APPEARS TO BE
GREATEST ALONG/AHEAD OF THE COLD FRONT INTO FRIDAY. DECREASING
THICKNESSES IN COLDER AIR BEHIND THE FRONT PORTEND A CHANGE BACK TO
SNOW FROM THE WEST FRIDAY.
THINGS LOOK POTENTIALLY INTERESTING JUST BEYOND THE END OF DAY
7...AS SOUTHWEST-NORTHEAST ORIENTED BAROCLINIC ZONE COULD BECOME THE
FOCUS FOR A COUPLE OF ROUNDS OF WINTRY PRECIP SOMEWHERE FROM HERE
INTO THE OHIO VALLEY...WHILE HIGH PRESSURE AND A RETURN TO
SUB-AVERAGE TEMPS BUILD BACK ACROSS THE UPPER MIDWEST.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LGT SNOW WILL PERSIST THROUGH EARLY AFTN. PERIOD OF MODERATE
SNOW BETWEEN 08-11Z.
* CIGS STEADILY LOWER TO ARND IFR...WITH A PERIOD OF LIFT PSBL
WITH THE MOD SNOW. THEN IFR CONDS PERSIST THRU MID-AFTN.
* E/NE WINDS 08-11KT THRU 16Z...THEN WINDS TURNS NE TO N LATE
AFTN/EVE.
BEACHLER
//DISCUSSION...UPDATED 06Z...
WINTER STORM CONTINUES TO ROTATE ACROSS THE REGION...SPREADING LGT
SNOW ACROSS NORTHERN IL/NORTHWEST IN AIRFIELDS. THE IFR CONDS HAVE
BEEN HOLDING FURTHER SOUTH OF ORD AT MDW...HOWEVER EXPECT OVER THE
NEXT COUPLE OF HOURS THIS LINE TO LIFT NORTH AND ORD WILL SEE IFR
CONDS DEVELOP. GUIDANCE CONTINUES TO INDICATE A BURST OF MODERATE
TO POSSIBLY A BRIEF HVY SNOW BETWEEN 08-11Z. IFR CONDS WILL THEN
PREVAIL AT MOST TAF SITES...WITH THE EXCEPTION OF RFD WHICH WILL
REMAIN JUST NORTHWEST OF THE STEADIER SNOW. AS THE LOW PRESSURE
LIFTS NORTHEAST...WINDS WILL STEADILY TURN NORTHEAST THEN
NORTHWEST. AS WINDS TURN NORTHEAST TO NORTHWEST THE PRECIP WILL
STEADILY PUSH EAST...AND BRING A SLOW IMPROVEMENT TO THE IFR CONDS
TO MVFR CIGS BY 00Z SUN.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN SNOW PERSISTING THRU EARLY AFTN.
* MEDIUM CONFIDENCE IN SNOW INTENSITY.
* MEDIUM/HIGH CONFIDENCE DURATION OF IFR WILL BE LONGER AT MDW.
* HIGH CONFIDENCE IN WIND DIR/SPEED.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...MVFR WITH A CHC OF SNOW.
MONDAY...SLIGHT CHC OF SNOW.
TUESDAY-WEDNESDAY...VFR LIKELY.
THURSDAY...CHC OF RAIN OR SNOW.
MTF
&&
.MARINE...
144 PM CST
A LARGE AREA OF HIGH PRESSURE IS SETTLING OVER THE SERN CONUS AS WEAK
LOW PRESSURE MOVING ACROSS NRN NEW ENGLAND DAGS A COLD FRONT DOWN
LAKE MICHIGAN. THE FRONT HAS STALLED OUT OVER THE SOUTHERN TIP OF
THE LAKE LEADING TO LIGHT AND VARIABLE WINDS OVER THE SOUTHERN TIP
OF THE LAKE. NORTH WINDS ARE STRENGTHENING OVER THE NORTHERN
PORTIONS OF THE LAKE AS ANOTHER AREA OF ARCTIC HIGH PRESSURE BUILDS
OUT OF CANADA AND SPREADS ACROSS THE NRN PLAINS AND UPPER GREAT
LAKES. THE FRONT OVER THE SRN PORTIONS OF THE LAKE WILL WASH OUT AS
A DOUBLE BARRELED LOW PRESSURE SYSTEM DEVELOPS OVER THE SRN AND
CNTRL PLAINS. THE COMPLEX LOW PRESSURE SYSTEM WILL TRACK EWD THIS
EVENING WITH ONE CIRCULATION CENTER TRACKING THROUGH CNTRL IL AND
ANOTHER TRACKING THROUGH THE LOWER MISSISSIPPI VALLEY. A WEAK
INVERTED SFC TROUGH AXIS ASSOCIATED WITH THE MORE NORTHERN OF THE
TWO LOWS WILL MOVE ACROSS THE LAKE EARLY TOMORROW. AS THE HIGH
BUILDS ACROSS THE UPPER GREAT LAKES THIS EVENING...WINDS OVER THE
ENTIRE LAKE WILL GRADUALLY TURN EASTERLY...BUT AS THE INVERTED
TROUGH AXIS CROSSES THE LAKE TOMORROW...WINDS OVER THE LAKE WILL
GRADUALLY BACK THROUGH NELY TO NORTHERLY TOMORROW EVENING AND THEN
THEN CONTINUE TO BACK TO NWLY BY LATE SATURDAY NIGHT AND EARLY
SUNDAY MORNING. AS COLDER AIR ASSOCIATED WITH THE ARCTIC HIGH IS
DRAWN OVER THE LAKE...THE STRONG COLD ADVECTION AND STRENGTHENING
PRESSURE GRADIENT WILL LEAD TO WINDS INCREASING TO AROUND 30KT
THROUGH THE DAY ON SUNDAY. WHILE GALES ARE NOT EXPECTED AT THIS
TIME...THE STRONG WINDS AND COLDER AIR WILL LEAD TO A CHANCE FOR
LIGHT TO MODERATE FREEZING SPRAY ON SUNDAY. THE BRISK NWLY WINDS
WILL PERSIST THROUGH SUNDAY NIGHT...AND THEN ANOTHER HIGH WILL BUILD
ACROSS LAKE MICHIGAN ON MONDAY...ALLOWING WINDS TO TEMPORARILY
SUBSIDE. AS THE HIGH MOVES OFF TO THE EAST ON TUESDAY...ANOTHER LOW
WILL TRACK ACROSS SCNTRL CANADA...LEADING TO INCREASING SWLY-WLY
WINDS BY TUESDAY...WHICH SHOULD PERSIST THROUGH THE MIDDLE OF NEXT
WEEK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ033-ILZ039 UNTIL NOON SATURDAY.
WINTER WEATHER ADVISORY...ILZ014 UNTIL 6 PM SATURDAY.
WINTER WEATHER ADVISORY...ILZ019-ILZ021-ILZ022-ILZ023-ILZ032
UNTIL NOON SATURDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002 UNTIL NOON SATURDAY.
WINTER STORM WARNING...INZ010-INZ011-INZ019 UNTIL NOON SATURDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP TO WILMETTE HARBORS UNTIL 3 PM SATURDAY.
SMALL CRAFT ADVISORY...LMZ741-LMZ742-LMZ743...3 AM SATURDAY TO 3
PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
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Area Forecast Discussion
National Weather Service Lincoln IL
1105 PM CST Fri Dec 13 2013
.DISCUSSION...
ISSUED 837 PM CST Fri Dec 13 2013
Have made some minor tweaks to grids and reworded some of the
precip type wording for this evening. Otherwise, no major changes
anticipated.
Lull between initial wave along front to our northwest and the
main area of diffluence associated with approaching southern
stream system is moving into the region southeast of I-55. As
precip over Arkansas moves northeast, snow will likely increase in
coverage and intensity again after midnight. Current snow amount
forecasts may be a bit overdone in this area, but hesitate to make
major changes with the second wave yet to come.
Somewhat concerned about the area northwest of the Illinois River.
2-3 inches have been reported across Fulton County to this point
and that area remains in the deformation area and near the surface
warm front. Would not be surprised if several reports approach 6
inches in that area.
Barker
&&
.AVIATION...
ISSUED 1105 PM CST Fri Dec 13 2013
Evolution of winter system preceding pretty much as expected.
After a brief period of mix and freezing rain earlier this evening
at KSPI and KDEC, precipitation has transitioned to all snow. Due
to the showery nature of the snow, vsbys will vary widely and will
have to cover generally through the rest of the night with
occasional vsbys down as low as 3/4SM. Would like to include more
detail, but impossible given nature of precipitation. Will keep at
least some mention of -SN around much of the day tomorrow until
the main wave axis moves through around 00z.
Upstream cigs are widespread IFR and will generally follow until
surface low moves east of the area 15-18z.
Warm front is bisecting terminals at 05z with KPIA in northeast
flow and the remainder of the sites continuing from 140-100
degrees. Latest model suite suggests that low will move along I-64
which should shift winds to 010-060 after 12z and then 300-350
degrees by 00z as the low pulls east.
Barker
&&
.PREV DISCUSSION...
ISSUED 205 PM CST Fri Dec 13 2013
Clouds continue to lower and thicken this afternoon ahead of the winter
storm system expected to affect our area tonight into Saturday. Already
seeing some light rain and sleet pushing into extreme southwest IL early
this afternoon as the upper level wave tracks across the southern Plains.
SHORT TERM...Tonight through Monday
Significant snowfall expected over parts of central through east
central Illinois tonight thru Saturday morning...but not much in
the way of strong winds with this particular storm system.
The main forecast challenge this period will be with snowfall totals
starting tonight thru early Saturday afternoon. Will continue to hold
on to the winter weather advisory with a few locations across central
thru east central Illinois edging close to 6 inches by the time the
snow tapers off to flurries Saturday afternoon. Forecast soundings,
at least for a few hours late this afternoon into early this evening,
continues to suggest a brief period of rain, sleet and possibly some
freezing rain over parts of west central Illinois before we see the
lower layers saturate and cool sufficiently enough to support mostly
snow thru the overnight hours. NAM-WRF time height cross sections
indicate the best forcing coupled with the deeper moisture/and dendritic
growth zone will be mainly tonight thru about 14z Saturday. Using a
13:1 SLR indicates 4 to 6 inches will be common across the area by the
time the snow diminishes on Saturday.
Still a bit concerned about the potential for banding, especially
along the inverted trof, which is expected to push across our area
early Saturday morning. Several of the hi-res models suggest the
threat is there but unfortunately, are not very consistent in depicting
the location. Past few runs of the HRRR have indicated one band to move
north across the area this evening, with a break over parts of central
thru east central IL around midnight, before another band pushes
acrs the area towards morning with the inverted trof. Wouldn`t at all
be surprised to see a few areas with 6 to 8 inches accumulation by late
Saturday morning, but at this time, the threat appears too isolated.
Models are a bit more consistent in showing an increase in snow totals
just to our east as the weak surface low and inverted trof shift off
to our east and we see a better coupled 250mb jet structure and
associated upper level divergence.
The upper level wave and surface reflection should push well off
to our east by late tomorrow afternoon with all of the precip shifting
out of the forecast area. The weather should be on the quiet side for
the rest of the short term period with a brief cool down in the wake
of the winter system Saturday night through Sunday night before we see
milder temperatures move into our area early next week.
LONG TERM...Tuesday through Friday
Medium range models indicate some fast moving waves approaching
our area from the northwest at the start of this forecast period
with little in the way of moisture available to produce much in
the way of precip in our area. The first such wave will move across
the lower Great Lakes on Monday with a hint for some very light
precip during the day, mainly to our north. The next wave moves
quickly southeast along the tight 850 mb baroclinic zone on Tue,
at least according to the latest ECMWF, with again little in the
way of moisture to work with. Will continue to keep the first part
of the week dry but could see some low chance pops added in later
forecasts.
Warmer temperatures expected in the Wed-Fri time frame as a deep
upper level trof drops southeast into the southern Rockies and
brings about a strong southwest flow aloft over our area. This
should result in mild temps, at least compared to what we have
been experiencing, through the end of the week. However, as the
deep upper level trof edges east into the central Plains, a strong
Arctic cold front will approach our area on Friday increasing the
precip chances Thursday night into Friday, followed by much colder
weather for next weekend.
Smith
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until Noon CST Saturday FOR ILZ038-
042>046-051>057-061>063-066>068-071>073.
WINTER WEATHER ADVISORY until 6 AM CST Saturday FOR ILZ027>031-
036-037-040-041-047>050.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
358 AM EST SAT DEC 14 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 356 AM EST SAT DEC 14 2013
ACCUMULATING SNOW WILL CONTINUE ACROSS MUCH OF THE FORECAST AREA
TODAY AS LOW PRESSURE TRACKS THROUGH THE OHIO VALLEY. ARCTIC AIR
WILL RETURN TONIGHT AS THE STORM MOVES AWAY TO THE EAST...WITH
CHILLY TEMPERATURES INTO THE EARLY PART OF THE WEEK. HIGH PRESSURE
WILL BRING DRY WEATHER AND A WARMING TREND THROUGH MIDWEEK.
UNSETTLED WEATHER RETURNS LATE THURSDAY AND FRIDAY AS LOW PRESSURE
TRACKS THROUGH THE REGION...WITH TEMPERATURES WARM ENOUGH FOR
PRECIPITATION TO FALL AS RAIN ACROSS CENTRAL INDIANA.
&&
.NEAR TERM /TODAY/...
ISSUED AT 356 AM EST SAT DEC 14 2013
COMPLEX WINTER STORM ONGOING ACROSS THE REGION EARLY THIS MORNING.
STEADIER SNOWS CONTINUE TO FALL OVER NORTHERN COUNTIES WITH A DRY
SLOT FURTHER SOUTH LIMITING PRECIP TO VERY LIGHT SNOW OR SHUTTING IT
OFF COMPLETELY ACROSS MUCH OF THE REST OF THE FORECAST AREA. BROADER
AREA OF HEAVIER PRECIPITATION QUICKLY EXPANDING NORTHEAST OUT OF THE
LOWER OHIO VALLEY. TEMPS WERE IN THE LOWER AND MIDDLE 30S AS OF 08Z.
DRY SLOT IS TAKING ITS TIME TO FILL IN...BUT EXPECT AREA OF HEAVIER
PRECIPITATION WILL EXPAND INTO THE FORECAST AREA OVER THE NEXT
SEVERAL HOURS WITH SNOWFALL COMMENCING ONCE AGAIN IN LOCATIONS WHERE
IT HAS STOPPED. RAP/NAM BOTH INDICATING A 50KT LOW LEVEL JET RIDING
UP THE MISSISSIPPI VALLEY AND CONTRIBUTING TO THE EXPANSION OF
PRECIP OVER THE LOWER OHIO VALLEY. THE LOW LEVEL JET WILL SHIFT EAST
ACROSS THE REGION AHEAD OF THE 850MB LOW THROUGH
MIDDAY...MAINTAINING A PLENTIFUL SURGE OF LOW LEVEL MOISTURE INTO
THE REGION. MAIN UPPER LEVEL WAVE LOCATED OVER SOUTHWEST MISSOURI
EARLY THIS MORNING WILL LIFT NORTHEAST ACROSS THE FORECAST AREA BY
EARLY AFTERNOON. SHORT RANGE MODEL GUIDANCE CONTINUING TO ADVERTISE
A DEFORMATION AXIS AND FRONTOGENETICAL FORCING WITHIN THE MID LEVELS
EXPANDING INTO THE FORECAST AREA PRIOR TO DAYBREAK AHEAD OF THE
UPPER WAVE.
ALL OF THESE FEATURES REMAIN SUPPORTIVE OF THE RESUMPTION OF
WIDESPREAD SNOW AND EXPECTATION FOR ADDITIONAL ACCUMULATIONS INTO
THE EARLY AFTERNOON...ESPECIALLY ACROSS THE NORTHERN HALF OF THE
FORECAST AREA. WITH THAT BEING SAID...TEMPERATURES WITHIN THE
BOUNDARY LAYER NEED TO BE MONITORED OVER THE NEXT SEVERAL HOURS AS
IMPACTS TO PRECIP TYPE OVER SOUTHERN COUNTIES AND SNOWFALL RATIOS IN
GENERAL ARE POSSIBLE. LAPS SOUNDINGS INDICATING A VERY SHALLOW LAYER
OF AIR NEAR THE SURFACE THAT SITS JUST ABOVE FREEZING OVER THE
SOUTHERN HALF OF THE FORECAST AREA WITH TEMPS AT 32-35F. WITH THE
LOW LEVEL JET TRANSPORTING SLIGHTLY WARMER BOUNDARY LAYER AIR NORTH
OVER THE NEXT FEW HOURS...EXPECTING SURFACE TEMPS TO MOVE LITTLE AND
MAY EVEN RISE A FEW DEGREES AFTER DAYBREAK. OVERALL...LOW LEVEL
THERMALS OVER THE NEXT SEVERAL HOURS REMAIN SUGGESTIVE OF SNOW AS
RATES INTENSIFY WITH THE EXPANSION OF THE PRECIP SHIELD. AS SLIGHTLY
WARMER AIR NOSES INTO SOUTHERN COUNTIES WITH THE LOW LEVEL JET AFTER
DAYBREAK HOWEVER...POTENTIAL FOR SOME LIGHT RAIN TO MIX IN WITH THE
SNOW. RAP AND NAM ARE THE MOST AGGRESSIVE WITH BRINGING THE 0C LINE
AT 850MB ACROSS THE SOUTHEASTERN HALF OF THE FORECAST AREA THROUGH
18Z...BOTH HINTING AT A TROWAL ROTATING INTO OUR SOUTHEAST AND
EASTERN COUNTIES. CONSIDERING RECENT TRENDS AND THE FACT THAT
SURFACE TEMPS ARE RUNNING A FEW DEGREES WARMER THAN PREVIOUSLY
THOUGHT...WILL BRING CHANCE FOR RAIN TO MIX IN WITH SNOW TO A
VINCENNES-BEDFORD-GREENSBURG LINE BY MID MORNING CONTINUING INTO
EARLY AFTERNOON.
CONSIDERING ABOVE THOUGHTS AND TAKING INTO ACCOUNT LIQUID TO
SNOWFALL RATIOS LIKELY REMAINING NEAR 10-1 FOR MUCH OF THE FORECAST
AREA FOR THE DURATION OF THE EVENT...HAVE TRIMMED TOTAL SNOWFALL
AMOUNTS A BIT OVER ALL BUT FAR NORTHERN SECTIONS. TOTAL SNOW ACCUMS
INCLUDING WHAT FELL SINCE FRIDAY EVENING STILL EXPECTED TO AROUND
6-7 INCHES OVER FAR NORTHERN COUNTIES...DIMINISHING TO 4-5 ALONG THE
I-70 CORRIDOR. FURTHER SOUTH...EXPECTING TOTALS GENERALLY AT 1-3
INCHES. THE NORTHWARD EXTENT OF THE ABOVE FREEZING AIR WITHIN THE
BOUNDARY LAYER AND THE POSSIBILITY OF ENHANCED FORCING IN THE
VICINITY OF A TROWAL COULD LEAD TO FURTHER ADJUSTMENTS IN THESE
AMOUNTS AND WILL CONTINUE TO MONITOR. THE WARNING AND ADVISORY WILL
CONTINUE IN THEIR CURRENT STATES THROUGH 23Z.
TEMPS...NEARLY STEADY TEMPS EXPECTED TODAY BUT IN GENERAL STILL FEEL
MOS IS TOO WARM WITH HIGHS. LEANED CLOSER TO CONSALL WITH TEMPS
RANGING FROM THE LOWER 30S NORTH TO MID 30S SOUTH.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 356 AM EST SAT DEC 14 2013
FORECAST CHALLENGES FOCUS ON MINOR SNOW CHANCES AND TEMPERATURES AS
COLDER AIR RETURNS FOR MUCH OF THE SHORT TERM.
ANY LINGERING LIGHT SNOW ON THE BACK SIDE OF THE DEPARTING SYSTEM
WILL END DURING THE EVENING...POSSIBLY AS A BRIEF PERIOD OF DRIZZLE
OR FREEZING DRIZZLE AS DRIER AIR DEEPENS ABOVE THE BOUNDARY LAYER.
LOW CLOUDS WILL PERSIST ALL NIGHT AS MOISTURE REMAINS TRAPPED
BENEATH A SHARP INVERSION.
THE PASSAGE OF TWO DEEP UPPER LOWS TO THE NORTH OF THE GREAT LAKES
WILL MAINTAIN BROAD TROUGHING ALOFT AND A GENERAL NORTHWEST FLOW
THROUGHOUT THE PERIOD. SEVERAL DISTURBANCES ALOFT WILL TRAVERSE THE
REGION MAINTAINING MOSTLY CLOUDY CONDITIONS AND BRINGING PERIODIC
LIGHT SNOW SHOWERS AND FLURRIES ACROSS MUCH OF THE FORECAST AREA.
FLURRIES ARE POSSIBLE WITHIN A BROAD CYCLONIC FLOW SUNDAY AND SUNDAY
NIGHT. STRONGER UPPER WAVE SET TO TRACK ACROSS THE LOWER GREAT LAKES
MONDAY AND WILL CARRY CHANCES FOR SNOW SHOWERS THROUGHOUT THE DAY.
SOUTHERLY FLOW WILL DEVELOP ON THE BACK SIDE OF A SURFACE HIGH
PRESSURE RIDGE BY MONDAY ALLOWING FOR WARM ADVECTION TO DEVELOP WITH
MODERATING TEMPS.
TEMPS...PREFER THE COLDER MAVMOS THROUGH MUCH OF THE PERIOD AS IT
APPEARS TO CAPTURE THE INFLUENCE FROM THE LEFTOVER SNOWPACK FROM
STORM TODAY BETTER. HIGHS WILL FALL BACK INTO THE LOWER/MIDDLE 20S
ON SUNDAY WITH STRONG COLD ADVECTION. THE SHIFT TO SOUTHERLY FLOW
MONDAY WILL ALLOW FOR A RECOVERY INTO THE 30S OVER SOUTHERN
COUNTIES. LOWS IN THE TEENS TONIGHT AND SUNDAY NIGHT WILL RECOVER
INTO THE 20S MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
ISSUED AT 357 AM EST SAT DEC 14 2013
THE EXTENDED PERIOD WILL START OUT WITH WEAKS SHORTWAVES ROTATING
AROUND AN UPPER LOW OVER ONTARIO. THIS WILL RESULT IN LIGHT SNOW
SHOWERS OVER NORTHERN INDIANA. HOWEVER...CHOSE TO LEAVE PRECIP OUT
OF CENTRAL INDIANA ON TUESDAY SINCE BEST LIFT WILL BE NORTH OF
FORECAST AREA. DRY CONDITIONS WILL PREVAIL THROUGH MID-WEEK WITH
DECENT SUBSIDENCE ALOFT. HOWEVER...THE RIDGING OVER THE CENTRAL
U.S. WILL START TO BREAK DOWN BY THURSDAY AS A LOW PRESSURE SYSTEM
STRENGTHENS OVER THE WESTERN UNITED STATES. MEANWHILE...WARM AIR
WILL BE ADVECTED INTO CENTRAL INDIANA AHEAD OF A SURFACE
LOW...RESULTING IN ABOVE NORMAL TEMPERATURES. PRECIP ASSOCIATED
WITH THAT SURFACE LOW WILL INITIALLY FALL IN THE FORM OF RAIN ON
THURSDAY NIGHT AND FRIDAY...AND THEN TRANSITION TO A RAIN/SNOW MIX
AS COLDER AIR FILTERS IN BEHIND THE ASSOCIATED COLD FRONT.
&&
.AVIATION /DISCUSSION FOR THE 14/09Z TAF UPDATE/...
ISSUED AT 330 AM EST SAT DEC 14 2013
UPDATE...
NO MAJOR CHANGES. CONDITIONS CONTINUE TO FLUCTUATE BETWEEN MVFR
AND IFR CATEGORIES. MADE MINOR ADJUSTMENTS TO REFLECT CURRENT
OBSERVATIONS.
PREVIOUS DISCUSSION...
FLUCTUATING MVFR TO IFR THROUGH MUCH OF THE NIGHT...WITH CONDITIONS
WORSENING AGAIN BY DAYBREAK AND REMAINING IFR MUCH OF THE DAY.
SNOW HAS BECOME MORE SHOWERY IN THE WAKE OF THE FIRST WAVE...BUT
EXPECT THE NEXT WAVE TO INCREASE BY DAYBREAK. MAY SEE SOME LIFR AT
TIMES DURING THE MORNING TO MIDDAY HOURS.
WINDS WILL BE BELOW 10KT THROUGH THE PERIOD...LIMITING BLOWING OF
SNOW. WINDS WILL BE EASTERLY AND THEN BECOME NORTHERLY LATE IN THE
PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
INZ053>057-060>065-067>072.
WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR INZ021-
028>031-035>049-051-052.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...NIELD/TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
356 AM EST SAT DEC 14 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 356 AM EST SAT DEC 14 2013
ACCUMULATING SNOW WILL CONTINUE ACROSS MUCH OF THE FORECAST AREA
TODAY AS LOW PRESSURE TRACKS THROUGH THE OHIO VALLEY. ARCTIC AIR
WILL RETURN TONIGHT AS THE STORM MOVES AWAY TO THE EAST...WITH
CHILLY TEMPERATURES INTO THE EARLY PART OF THE WEEK. HIGH PRESSURE
WILL BRING DRY WEATHER AND A WARMING TREND THROUGH MIDWEEK.
UNSETTLED WEATHER RETURNS LATE THURSDAY AND FRIDAY AS LOW PRESSURE
TRACKS THROUGH THE REGION...WITH TEMPERATURES WARM ENOUGH FOR
PRECIPITATION TO FALL AS RAIN ACROSS CENTRAL INDIANA.
&&
.NEAR TERM /TODAY/...
ISSUED AT 356 AM EST SAT DEC 14 2013
COMPLEX WINTER STORM ONGOING ACROSS THE REGION EARLY THIS MORNING.
STEADIER SNOWS CONTINUE TO FALL OVER NORTHERN COUNTIES WITH A DRY
SLOT FURTHER SOUTH LIMITING PRECIP TO VERY LIGHT SNOW OR SHUTTING IT
OFF COMPLETELY ACROSS MUCH OF THE REST OF THE FORECAST AREA. BROADER
AREA OF HEAVIER PRECIPITATION QUICKLY EXPANDING NORTHEAST OUT OF THE
LOWER OHIO VALLEY. TEMPS WERE IN THE LOWER AND MIDDLE 30S AS OF 08Z.
DRY SLOT IS TAKING ITS TIME TO FILL IN...BUT EXPECT AREA OF HEAVIER
PRECIPITATION WILL EXPAND INTO THE FORECAST AREA OVER THE NEXT
SEVERAL HOURS WITH SNOWFALL COMMENCING ONCE AGAIN IN LOCATIONS WHERE
IT HAS STOPPED. RAP/NAM BOTH INDICATING A 50KT LOW LEVEL JET RIDING
UP THE MISSISSIPPI VALLEY AND CONTRIBUTING TO THE EXPANSION OF
PRECIP OVER THE LOWER OHIO VALLEY. THE LOW LEVEL JET WILL SHIFT EAST
ACROSS THE REGION AHEAD OF THE 850MB LOW THROUGH
MIDDAY...MAINTAINING A PLENTIFUL SURGE OF LOW LEVEL MOISTURE INTO
THE REGION. MAIN UPPER LEVEL WAVE LOCATED OVER SOUTHWEST MISSOURI
EARLY THIS MORNING WILL LIFT NORTHEAST ACROSS THE FORECAST AREA BY
EARLY AFTERNOON. SHORT RANGE MODEL GUIDANCE CONTINUING TO ADVERTISE
A DEFORMATION AXIS AND FRONTOGENETICAL FORCING WITHIN THE MID LEVELS
EXPANDING INTO THE FORECAST AREA PRIOR TO DAYBREAK AHEAD OF THE
UPPER WAVE.
ALL OF THESE FEATURES REMAIN SUPPORTIVE OF THE RESUMPTION OF
WIDESPREAD SNOW AND EXPECTATION FOR ADDITIONAL ACCUMULATIONS INTO
THE EARLY AFTERNOON...ESPECIALLY ACROSS THE NORTHERN HALF OF THE
FORECAST AREA. WITH THAT BEING SAID...TEMPERATURES WITHIN THE
BOUNDARY LAYER NEED TO BE MONITORED OVER THE NEXT SEVERAL HOURS AS
IMPACTS TO PRECIP TYPE OVER SOUTHERN COUNTIES AND SNOWFALL RATIOS IN
GENERAL ARE POSSIBLE. LAPS SOUNDINGS INDICATING A VERY SHALLOW LAYER
OF AIR NEAR THE SURFACE THAT SITS JUST ABOVE FREEZING OVER THE
SOUTHERN HALF OF THE FORECAST AREA WITH TEMPS AT 32-35F. WITH THE
LOW LEVEL JET TRANSPORTING SLIGHTLY WARMER BOUNDARY LAYER AIR NORTH
OVER THE NEXT FEW HOURS...EXPECTING SURFACE TEMPS TO MOVE LITTLE AND
MAY EVEN RISE A FEW DEGREES AFTER DAYBREAK. OVERALL...LOW LEVEL
THERMALS OVER THE NEXT SEVERAL HOURS REMAIN SUGGESTIVE OF SNOW AS
RATES INTENSIFY WITH THE EXPANSION OF THE PRECIP SHIELD. AS SLIGHTLY
WARMER AIR NOSES INTO SOUTHERN COUNTIES WITH THE LOW LEVEL JET AFTER
DAYBREAK HOWEVER...POTENTIAL FOR SOME LIGHT RAIN TO MIX IN WITH THE
SNOW. RAP AND NAM ARE THE MOST AGGRESSIVE WITH BRINGING THE 0C LINE
AT 850MB ACROSS THE SOUTHEASTERN HALF OF THE FORECAST AREA THROUGH
18Z...BOTH HINTING AT A TROWAL ROTATING INTO OUR SOUTHEAST AND
EASTERN COUNTIES. CONSIDERING RECENT TRENDS AND THE FACT THAT
SURFACE TEMPS ARE RUNNING A FEW DEGREES WARMER THAN PREVIOUSLY
THOUGHT...WILL BRING CHANCE FOR RAIN TO MIX IN WITH SNOW TO A
VINCENNES-BEDFORD-GREENSBURG LINE BY MID MORNING CONTINUING INTO
EARLY AFTERNOON.
CONSIDERING ABOVE THOUGHTS AND TAKING INTO ACCOUNT LIQUID TO
SNOWFALL RATIOS LIKELY REMAINING NEAR 10-1 FOR MUCH OF THE FORECAST
AREA FOR THE DURATION OF THE EVENT...HAVE TRIMMED TOTAL SNOWFALL
AMOUNTS A BIT OVER ALL BUT FAR NORTHERN SECTIONS. TOTAL SNOW ACCUMS
INCLUDING WHAT FELL SINCE FRIDAY EVENING STILL EXPECTED TO AROUND
6-7 INCHES OVER FAR NORTHERN COUNTIES...DIMINISHING TO 4-5 ALONG THE
I-70 CORRIDOR. FURTHER SOUTH...EXPECTING TOTALS GENERALLY AT 1-3
INCHES. THE NORTHWARD EXTENT OF THE ABOVE FREEZING AIR WITHIN THE
BOUNDARY LAYER AND THE POSSIBILITY OF ENHANCED FORCING IN THE
VICINITY OF A TROWAL COULD LEAD TO FURTHER ADJUSTMENTS IN THESE
AMOUNTS AND WILL CONTINUE TO MONITOR. THE WARNING AND ADVISORY WILL
CONTINUE IN THEIR CURRENT STATES THROUGH 23Z.
TEMPS...NEARLY STEADY TEMPS EXPECTED TODAY BUT IN GENERAL STILL FEEL
MOS IS TOO WARM WITH HIGHS. LEANED CLOSER TO CONSALL WITH TEMPS
RANGING FROM THE LOWER 30S NORTH TO MID 30S SOUTH.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 356 AM EST SAT DEC 14 2013
FORECAST CHALLENGES FOCUS ON MINOR SNOW CHANCES AND TEMPERATURES AS
COLDER AIR RETURNS FOR MUCH OF THE SHORT TERM.
ANY LINGERING LIGHT SNOW ON THE BACK SIDE OF THE DEPARTING SYSTEM
WILL END DURING THE EVENING...POSSIBLY AS A BRIEF PERIOD OF DRIZZLE
OR FREEZING DRIZZLE AS DRIER AIR DEEPENS ABOVE THE BOUNDARY LAYER.
LOW CLOUDS WILL PERSIST ALL NIGHT AS MOISTURE REMAINS TRAPPED
BENEATH A SHARP INVERSION.
THE PASSAGE OF TWO DEEP UPPER LOWS TO THE NORTH OF THE GREAT LAKES
WILL MAINTAIN BROAD TROUGHING ALOFT AND A GENERAL NORTHWEST FLOW
THROUGHOUT THE PERIOD. SEVERAL DISTURBANCES ALOFT WILL TRAVERSE THE
REGION MAINTAINING MOSTLY CLOUDY CONDITIONS AND BRINGING PERIODIC
LIGHT SNOW SHOWERS AND FLURRIES ACROSS MUCH OF THE FORECAST AREA.
FLURRIES ARE POSSIBLE WITHIN A BROAD CYCLONIC FLOW SUNDAY AND SUNDAY
NIGHT. STRONGER UPPER WAVE SET TO TRACK ACROSS THE LOWER GREAT LAKES
MONDAY AND WILL CARRY CHANCES FOR SNOW SHOWERS THROUGHOUT THE DAY.
SOUTHERLY FLOW WILL DEVELOP ON THE BACK SIDE OF A SURFACE HIGH
PRESSURE RIDGE BY MONDAY ALLOWING FOR WARM ADVECTION TO DEVELOP WITH
MODERATING TEMPS.
TEMPS...PREFER THE COLDER MAVMOS THROUGH MUCH OF THE PERIOD AS IT
APPEARS TO CAPTURE THE INFLUENCE FROM THE LEFTOVER SNOWPACK FROM
STORM TODAY BETTER. HIGHS WILL FALL BACK INTO THE LOWER/MIDDLE 20S
ON SUNDAY WITH STRONG COLD ADVECTION. THE SHIFT TO SOUTHERLY FLOW
MONDAY WILL ALLOW FOR A RECOVERY INTO THE 30S OVER SOUTHERN
COUNTIES. LOWS IN THE TEENS TONIGHT AND SUNDAY NIGHT WILL RECOVER
INTO THE 20S MONDAY NIGHT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 211 PM EST FRI DEC 13 2013
TRANQUIL WEATHER MOST OF THIS TIME FRAME WITH WARM UP COMING LATE
WEEK ALONG WITH RAIN. MODELS IN DECENT ENOUGH AGREEMENT FOR MOST
PERIODS AND HAVE USED A BLEND. IN LARGER PICTURE BROAD EASTERN
NORTH AMERICA TROUGH GRADUALLY SHIFTS OFF THE COAST AS FLOW ZONES
OUT THEN TURNS SOUTHWESTERLY FOR US AS UPPER TROUGH DIGS INTO THE
WESTERN US AND THUS THE TRANSITION FROM COLD TO MILD.
THIS PERIOD WILL START OUT WITH A DECENT SNOWPACK THAT WILL HAVE
AN IMPACT ON KEEPING TEMPS A BIT COOLER THAN THEY WOULD OTHERWISE
BE FOR MUCH OF THE WEEK. LATE WEEK STRONG STORM SYSTEM BRINGS
SUBSTANTIALLY WARMER TEMPS BEGINNING THURSDAY AND ATTENDANT
PRECIPITATION SHOULD BE AS RAIN RELATIVE TO RECENT SNOWY PERIOD.
TEENS AND LOWER 20S MIN TEMPS WILL BE REPLACED BY ABOVE FREEZING
MINS BY FRIDAY MORNING. MAX TEMPS IN 30S VS 20S WILL FEEL
RELATIVELY MILD EARLY WEEK BUT WILL WARM TO UPPER 30S AND 40S
THURSDAY AND THEN UPPER 40S AND 50S FRIDAY SO A LATE WEEK SNOWMELT
COMBINED WITH RAINS COULD BRING SOME RIVER ISSUES.
&&
.AVIATION /DISCUSSION FOR THE 14/09Z TAF UPDATE/...
ISSUED AT 330 AM EST SAT DEC 14 2013
UPDATE...
NO MAJOR CHANGES. CONDITIONS CONTINUE TO FLUCTUATE BETWEEN MVFR
AND IFR CATEGORIES. MADE MINOR ADJUSTMENTS TO REFLECT CURRENT
OBSERVATIONS.
PREVIOUS DISCUSSION...
FLUCTUATING MVFR TO IFR THROUGH MUCH OF THE NIGHT...WITH CONDITIONS
WORSENING AGAIN BY DAYBREAK AND REMAINING IFR MUCH OF THE DAY.
SNOW HAS BECOME MORE SHOWERY IN THE WAKE OF THE FIRST WAVE...BUT
EXPECT THE NEXT WAVE TO INCREASE BY DAYBREAK. MAY SEE SOME LIFR AT
TIMES DURING THE MORNING TO MIDDAY HOURS.
WINDS WILL BE BELOW 10KT THROUGH THE PERIOD...LIMITING BLOWING OF
SNOW. WINDS WILL BE EASTERLY AND THEN BECOME NORTHERLY LATE IN THE
PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
INZ053>057-060>065-067>072.
WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR INZ021-
028>031-035>049-051-052.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TUCEK
AVIATION...NIELD/TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1151 PM EST Fri Dec 13 2013
...Updated Aviation Discussion...
...Forecast Update...
Issued at 955 PM EST Fri Dec 13 2013
That first wave of light to moderate precip (though the flakes at
times were large) that came through has helped to raise dewpoints
quite a bit, and they have stayed that way a couple of hours now
with upstream locations not dropping too much. Forecast soundings
from the models look like they are overdoing the dry air that was
supposed to follow that wave, though the RUC does keep higher
dewpoint air over us now. Given these changes, think the rain/snow
transition line can be moved north. Have adjusted the forecast as
such and now have snow totals of 1-2 inches only over my northern
stripe of counties as well as the northern parts of Perry and
Crawford. Thus have cancelled the advisory south of this line. Will
keep in a special weather statement for a mix of precip south of
that advisory.
Issued at 600 PM EST Fri Dec 13 2013
Seeing a NW/SE-oriented band of precipitation well out ahead of the
main rainmake for tonight. Several of the high-res models have
picked up on this band and then bring a quiet weather period behind
it for a few hours. Have adjusted our pop grids to match this trend
and to account for the earlier onset. Have had several PING reports
of snow coming out of that band and the ob at KOWB indicated a
rain/snow mix. Soundings indicate the dry air in the low levels is
helping to bring temperatures down quickly as this precipitation
falls into it. Temps over our area now are around 40, but within the
band over PAH`s area they have fallen to 34. Updated forecast will
be out shortly.
.SHORT TERM (Now through Saturday Night)...
Issued at 305 PM EST Fri Dec 13 2013
...A ROUND OF WINTERY WEATHER TONIGHT WITH LIGHT SNOW ACCUMULATIONS
ACROSS SOUTHERN INDIANA...
In the near term, mid-high level cloud cover is quickly
overspreading the region. Skies were partly to mostly cloudy and
with a southerly wind flow, temperatures have warmed into the 40s
across Kentucky with middle to upper 30s across southern Indiana.
We expect cloudy skies to persist for the rest of the afternoon and
into the early evening with temperatures falling back into the lower
30s across southern Indiana and into the middle-upper 30s in KY.
Latest model data continues to have pretty good continuity from
previous data sets. The models all indicate that an area of low
pressure over eastern TX will continue to deepen and head
northeastward through the heart of the Ohio Valley during the short
term forecast period. A large batch of precipitation will accompany
this feature and begin to overspread the region tonight. With
surface temperatures dropping to near the freezing mark, this will
bring a mixed bag of wintry weather to the area tonight...followed
by a cold rain for Saturday and then a transition back to snow
Saturday night as colder air moves into the region.
As precipitation moves eastward toward the region this evening, it
will encounter a relatively dry airmass that is in place. This can
easily be seen in the 12Z BNA and ILN sounding data. Precipitation
aloft will move into the region and begin to saturate the column
from top to bottom. Given the scope of isentropic lift and synoptic
scale ascent ahead of this system, it appears that it will take an
hour or two for the column to saturate down. With this top to
bottom saturation, we will see evaporative cooling effects in which
the lower atmosphere...while initially warm will cool to an extent
this evening. Thus, the initial precipitation developing across the
region looks to be in the form of rain with some sleet at the
onset. A mix of rain/sleet/snow is likely in areas north of the
river at onset due to a cooler atmospheric profile that is expected
to be in place.
As the evening wears on, we will see the rain/sleet mixture change
over to mainly a snow/sleet mixture across the northern half of
Kentucky and all of southern Indiana. Thermal profiles across
southern Kentucky suggest that rain will likely be the main
precipitation type...especially in areas south of a line from
Hartford to around Richmond, KY. As we head into the overnight
hours, we expect a snow/sleet mixture to continue across northern KY
with mainly snow and some sleet across southern Indiana.
Temperatures north of the BG/WK parkways look to cool into the lower
30s. Probably will see temperatures cool to around 32-34, but in
heavier bursts of precipitation that fall as snow, temperatures in
localized areas could drop to 29-30. As we head toward sunrise, all
of the available guidance suggests that low-level warm air advection
will push further northward into KY changing the sleet/snow mixture
over to plain rain. Only areas that look to remain snow by sunrise
would be along and north of the I-64 corridor into southern Indiana.
Low-level warm air advection is expected to continue into the day on
Saturday with most areas going over to cold rain during the day.
This low-level warm nose looks to push northward into southern
Indiana resulting in an eventual change over to mostly rain even
that far north. Precipitation will pull on off to the northeast as
the low-pressure system heads into New England. As this occurs,
colder air will be pulled back down into the region Saturday night.
This will result in any left over precipitation changing over to
light snow. However...model soundings do show a loss of substantial
moisture in the dendritic ice crystal layer so we could see more of
light freezing drizzle falling across much of the region Saturday
night despite having a large cold low-level airmass in place.
As mentioned above, temperatures tonight are expected to fall to
around 30 in areas north of the Ohio River. Areas south of the Ohio
River and north of the WK/BG Pkys should cool into the 32-34 degree
range. Areas south of the Parkways look to cool into the 34-36
degree range. Highs on Saturday look to warm into the 40s across KY
with middle 30s in southern Indiana. Lows Saturday night will drop
back into the 20s in all areas.
With regards to snowfall amounts, we continue to believe the area at
most risk for snowfall accumulation overnight will be in areas of
southern Indiana north of the I-64 corridor. Along the I-64
corridor we expect around an inch or two of snow accumulation. In
our northern row of counties (along/north of a Jasper to Deputy
line) two to three inches of snowfall will be possible. For this
reason, we will continue the Winter Weather Advisory for tonight and
into Saturday morning.
In areas south of the Ohio River...but north of the WK/BG Pkys,
snowfall accumulation will be substantially less due to the expected
wintry mixture and warmer surface temperatures. Generally think
that a coating to maybe a half inch will be possible along and north
of the BG/WK Parkways with a half to 1 inch possible up near the
I-64 corridor to near the Ohio River. In general, expect most
snowfall accumulations in this area will be mainly on grassy and
elevated surfaces, but some accumulation on roads will be possible
during heavier precipitation periods. Very little snow accumulation
is expected across south-central Kentucky as precipitation will
remain in the form of a cold rain.
Some minor snow accumulations are possible late Saturday night if
the colder air gets into the region more quickly than forecast and
if precipitation is slower to move out. The combination of wet
roads and falling temperatures made lead to slick spots developing
late Saturday night. We plan on addressing those concerns in the
Hazardous Weather Outlook product.
.LONG TERM (Sunday through Friday)...
Issued at 305 PM EST Fri Dec 13 2013
A dry northwesterly flow at 500mb will develop late Sunday in the
wake of Saturday`s system, which is forecast to deepen off the New
England Coast early Monday. With a broad cyclonic flow centered over
the Great Lakes, a couple of weak upper disturbances will rotate
through the northern Ohio Valley over the first several days of next
week. However any light snow or snow showers will likely stay
confined to northern Indiana and Ohio. The first feature may bring
light flurries late Monday as for south as southern Indiana. Our
second feature seems timed for late Tuesday, with only some variable
cloudiness associated with this feature.
Temperatures will tend to moderate through the week, but slowly at
first as warmer air across the southern plains will stay shunted to
our southwest by the Great Lakes longwave trough. High temperatures
Tuesday will rise around 5 to 8 degrees above Monday`s expected
highs in the Lower 40s. A weak frontal passage will cool down
Wednesday just a bit as high pressure builds overhead.
Monday and Tuesday will feature variably cloudy skies, as the
combination of residual low level moisture and upper level waves
will likely bring a few cloudy periods. Mostly clear skies
anticipated for Wednesday.
Mild temperatures will finally return for Thursday and Friday, and
possibly Saturday as well. A digging jet streak along the west coast
late Wednesday will act to amplify a trough over the Rockies by late
Thursday, in turn leading to cyclogenesis across the plains. Robust
southwesterly flow will develop across the Lower Ohio Valley by
Thursday, continuing Friday. Initially, on Thursday, recycled
continental air will lead to mostly clear skies. Eventually, Gulf
moisture will return by Friday into early Saturday, bringing very
mild temperatures and a potential for quite a bit of rain early next
weekend. Highs Thursday and especially Friday will reach the 50s.
&&
.AVIATION (06Z TAF Update)...
Updated at 1150 PM EST Fri Dec 13 2013
Precipitation continues to push back in across the area tonight. It
still looks like SDF and LEX may see a mix of rain and snow off an
on through the night. This should change to all rain by around
sunrise as warmer air pushes in. BWG is expected to stay all rain as
it will remain warmer there. Rain will continue through the day
before tapering off during the late afternoon to evening hours.
There may be a chance for some flurries or freezing drizzle tomorrow
night. However, confidence in this remains low, so will keep the
forecast dry for now.
As the atmosphere saturates tonight, ceilings will lower to MVFR and
then IFR during the early morning hours. Visibilities will likely
bounce around, but generally hold in the MVFR range. Low level
moisture will linger into Saturday night, so ceilings are not
expected to improve through this TAF period. Winds will become
variable today as the low pressure moves northeast along the Ohio
River. They will then shift to westerly/northwesterly this afternoon
and evening as the low moves east.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...WINTER WEATHER ADVISORY until 10 AM EST /9 AM CST/ Saturday FOR
INZ076>079-083-084-089.
&&
$$
Update.........RJS
Short Term.....MJ
Long Term......JSD
Aviation.......EER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
504 AM EST SAT DEC 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EST SAT DEC 14 2013
WV IMAGERY AND RAP ANALYSIS SHOW A LONG WAVE TROUGH OVER THE
CENTRAL CONUS...WITH MUCH OF THE ENERGY IN THE SOUTHERN STREAM
MOVING THROUGH THE SOUTHERN THIRD OF THE CONUS. CLOSER TO THE UPPER
GREAT LAKES...A SHORTWAVE IS CURRENTLY TRACKING THROUGH SOUTHERN
MANITOBA AND INTO NORTHERN MINNESOTA AT THIS TIME...WITH A BROAD
AREA OF MOISTURE AHEAD OF THIS WAVE IN MN/WI/MI. AT THE SURFACE...A
ELONGATED AREA OF 1034MB HIGH PRESSURE STRETCHES FROM LAKE WINNIPEG
EAST-SOUTHEAST INTO SOUTHWEST QUEBEC...WHILE A TROUGH STRETCHES
NORTHEAST INTO SOUTHERN WISCONSIN FROM A 1007MB LOW IN NORTH
CENTRAL TEXAS. THE FORCING FROM THE SHORTWAVE AND INCREASED
MOISTURE AHEAD OF IT HAS LED TO -SHSN OVER MINNESOTA OVER THE LAST
SEVERAL HOURS AND THEY HAVE EXPANDED EAST INTO WESTERN WISCONSIN.
CLOSER TO THE U.P. 850MB TEMPS OF -17 TO -20C OVER THE CWA HAS
COMBINED WITH LIGHT NORTHEAST TO EASTERLY FLOW TO LEAD TO LIGHT
LAKE EFFECT SNOW SHOWERS OVER SOUTH CENTRAL LAKE SUPERIOR. IT HAS
FINALLY STARTED TO PUSH TO THE NORTHEAST AS THE LOW LEVEL WINDS HAVE
SWITCHED TO THE SOUTH. INVERSION HEIGHTS OF 3-4KFT ON 00Z KINL
SOUNDING AND 08Z KMQT VAD PROFILE ARE LIKELY THE MAIN LIMITING
FACTOR TO THE SNOW OVERNIGHT...IN ADDITION TO THE VARIABLE LOW LEVEL
FLOW. FARTHER SOUTH...LAKE ENHANCED SNOWFALL CONTINUES OFF
LAKE MICHIGAN IN EAST CENTRAL AND PARTS OF NORTHEAST WISCONSIN.
THERE WAS A STRONGER BAND AFFECTING OCONTO EARLIER IN THE
NIGHT...BUT IT HAS SINCE WEAKENED. THERE ARE SOME HINTS THAT THE
LAKE EFFECT IS NEARING MENOMINEE...BUT VISIBILITIES THERE ARE STILL
10SM.
MUCH OF THE FORECAST FOR THE SHORT TERM WILL FOCUS ON THE SHORTWAVE
AND LAKE EFFECT/ENHANCED SNOWFALL UNDER VEERING LOW LEVEL WINDS TO
THE SOUTHEAST THROUGH THE EVENING. AS THE SHORTWAVE SHIFTS INTO
WISCONSIN AND UPPER MICHIGAN THIS AFTERNOON...A INVERTED TROUGH WILL
DEVELOP NORTHWEST FROM THE LOW MOVING INTO THE MID ATLANTIC STATES.
00Z KINL SOUNDING FAIRLY REPRESENTATIVE OF THE LIMITED MOISTURE IN
LOWER LEVELS ROTATING AROUND THE HIGH (VERY DRY BETWEEN
940-700MB)...BUT EXPECT THAT TO GIVEWAY FROM SOUTHWEST TO NORTHEAST
LATE THIS MORNING AND CONTINUE INTO THE AFTERNOON. ALREADY FAIRLY
MOIST ON THE 00Z KGRB SOUNDING AND WITH THAT CLOSE PROXIMITY AND
LIGHT NORTHEASTERLY PUSH AROUND THE HIGH...THE DRIER AIR SHOULD GIVE
AWAY FAIRLY EASILY. FORCING FROM THE SHORTWAVE AND INVERTED TROUGH
WILL DEVELOP LIGHT SNOW ACROSS MUCH OF THE AREA LATE THIS MORNING
BEFORE DIMINISHING FROM WEST TO EAST THROUGH THE LATE AFTERNOON AND
EVENING HOURS. FOCUS TURNS TO LAKE EFFECT/ENHANCED SNOWFALL.
FIRST...THE SNOW OVER SOUTH CENTRAL LAKE SUPERIOR SHOULD CONTINUE
TO DRIFT NORTHWEST THIS MORNING AND BRIEFLY CROSS THE KEWEENAW
PENINSULA BEFORE MOVING BACK INTO LAKE SUPERIOR. THE MAIN AREA OF
CONCERN IS FOR LAKE ENHANCED SNOWFALL ALONG THE BAY OF GREEN BAY.
INDICATIONS ARE THERE FROM THE MODELS AND THE DELTA-T VALUES
OF 18 TO 21 SUPPORT IT...BUT HIGHER RESOLUTION MODELS WHICH
TRADITIONALLY OVER DO QPF ARE STRUGGLING TO PUT OUT ANY SIGNIFICANT
VALUES OVER SOUTHERN MENOMINEE AND SOUTHEAST DELTA COUNTIES TODAY.
HAVE A FEELING THAT THE STRUGGLE TO PUT OUT ANY DECENT QPF IS
RELATED TO THE LOW LEVEL SHEAR INDICATED BY THE MODELS. THIS CAN BE
SEEN AT THE PRESENT TIME IN EAST CENTRAL WISCONSIN WHERE WINDS ARE
PREDOMINATELY EASTERLY IN THE LOWER LEVELS AND LAKE ENHANCEMENT IS
OCCURRING. BUT FARTHER NORTH ACROSS THE BAY OF GREEN BAY...THE DRIER
AIR COMBINED WITH WINDS VARYING IN DIRECTION DEPENDING ON LEVEL
(850MB VEERING SOUTHEAST...925MB STAYING MAINLY EASTERLY...AND
SURFACE WINDS NORTHEASTERLY) HAS BEEN LIMITING DEVELOPMENT THUS
FAR. THIS WILL LIKELY CONTINUE THROUGH THE AFTERNOON UNTIL THE
TROUGH DEVELOPS ACROSS THE AREA AND FOCUSES WINDS OUT OF THE
SOUTHEASTERLY DIRECTION THIS EVENING. AM WONDERING IF THIS SHEAR
WILL BE ENOUGH TO LIMIT ANY REAL STRONG LAKE ENHANCED BANDS. IN
ADDITION...INVERSION HEIGHTS AROUND MENOMINEE THIS MORNING ARE
AROUND 5-6KFT AND REMAINS THROUGH MUCH OF TODAY...LIKELY LIMITING
STRONG ENHANCEMENT AND HIGHER TOTALS. THEY ARE A LITTLE HIGHER
AROUND ESCANABA (6-7KFT THIS AFTERNOON/EVENING) AND WHEN COMBINED
WITH THE MORE UNIFORM FLOW THIS EVENING...THINK THAT IS WHEN THEY
WILL HAVE THE BEST OPPORTUNITY FOR MODERATE SNOWFALL. ON THE
POSITIVE SIDE...MUCH OF THE LAKE ENHANCED FORCING IS IN OR JUST
BELOW THE DGZ AND ALLOW FOR SNOW RATIOS TO BE HIGHER AND AROUND 20
TO 1. UNFORTUNATELY...DEALING WITH AROUND 20-1 SNOW RATIOS MAKES FOR
A DIFFICULT TIME ON PINNING DOWN AMOUNTS ON THESE LOWER END QPF
AMOUNTS. MODEL COBB SNOW AMOUNTS ARE ALL OVER THE BOARD WITH 12Z NAM
FOR KESC GIVING AROUND 3.5-4IN AND OUR LOCAL 00Z WRF-ARW HAS
3-3.8IN...WHILE THE 08Z RAP IS GIVING 1.3IN THROUGH 02Z. 03Z SREF
MEAN HAS 2.3-3.0 AND THINK THAT IS A REASONABLE COMPROMISE. AMOUNTS
FOR KMNM HAVE A SIMILAR RANGE...WITH THE HIGHEST AMOUNTS FROM THE
MODELS OF 4-5INCHES...BUT THOSE RUNS HAD 2IN OF ACCUMULATION ALREADY
EVEN THOUGH IT HASN/T EVEN STARTED SNOWING. THEREFORE...OPTED TO
LOWER AMOUNTS ABOUT AN INCH AND MAY NEED TO DO MORE IF THE SNOW
STRUGGLES TO DEVELOP THIS MORNING. STILL THINK THE HIGHEST AMOUNTS
WILL BE OVER THE GARDEN PENINSULA...WHERE AMOUNTS COULD REACH 5
INCHES.
OVERALL VERY UNCERTAIN ON SNOWFALL AMOUNTS FOR MENOMINEE AND DELTA
COUNTIES TODAY...LARGELY DUE TO THE LOW LEVEL SHEAR THAT LOOKS LIKE
IT WILL OCCUR. A LITTLE MORE CONFIDENCE IN PORTIONS OF DELTA AS
WINDS BECOME MORE FAVORABLE THIS EVENING AND THERE IS LESS
SHEAR...BUT EVEN THEN THE BANDS WILL LIKELY BE MOVING ENOUGH TO THE
EAST TO LIMIT SIGNIFICANT ACCUMULATIONS. THEREFORE...WILL KEEP THE
ADVISORY GOING FOR NOW (WITH WEAKER WORDING AND GREATER RANGE IN
TOTALS TO SHOW UNCERTAINTY) SINCE THEY SHOULD SEE SOME SNOW AND
ALLOW THE DAY SHIFT TO ASSESS THE SITUATION THROUGH THE MORNING.
WITH THE UNCERTAINTY...DID NOT EXPAND ADVISORY TO SOUTHERN
SCHOOLCRAFT FOR TONIGHT EVEN THOUGH THERE TOTALS ARE IN THE SAME
RANGE AS SOUTHERN DELTA COUNTY.
A SURFACE LOW LOOKS TO DEVELOP ALONG THE SURFACE TROUGH OVER
NORTHERN LAKE SUPERIOR TONIGHT AS A SECONDARY AND STRONGER
SHORTWAVE DROPS OVER LAKE SUPERIOR. THE FLOW AROUND THE LOW WILL
KEEP MUCH OF THE LAKE EFFECT AWAY FROM THE LAKE SUPERIOR SHORELINES
THIS EVENING...BEFORE WINDS SHIFT TO THE WEST-NORTHWEST OVER THE
WESTERN LAKE OVERNIGHT WITH THE LOW MOVING INTO THE EASTERN LAKE.
THEREFORE...SHOULD SEE LAKE EFFECT INCREASING OVER THE WESTERN HALF
OF THE CWA OVERNIGHT WITH THAT WINDSHIFT AND THE INTENSIFYING LOW
OVER THE NORTHERN/EASTERN LAKE. INVERSION HEIGHTS DO LOOK TO IMPROVE
TO AROUND 10KFT OVER THE WESTERN LAKE OVERNIGHT AND WITH THE HELP OF
THE ADDITIONAL MOISTENING TODAY FROM THE SURFACE TROUGH...THAT AREA
SHOULD BE ABLE TO REALIZE THOSE FAIRLY HIGH INVERSION HEIGHTS.
850MB TEMPS FALL FROM -16C AT 06Z TO -20C BY 12Z SUNDAY...SO LAKE
INSTABILITY IS PRESENT AND BUFKIT SOUNDINGS ARE SHOWING LAKE INDUCED
CAPES IN THE 400-600 J/KG RANGE. IN ADDITION...THE EXTRA
FORCING FROM THE SHORTWAVE (INCREASING MID LEVEL Q-VECTOR
CONVERGENCE) WILL PRODUCE A CONDUCIVE PERIOD FOR LAKE EFFECT
SNOWFALL. THUS...WOULD EXPECT THERE TO BE A FAIRLY DECENT BURST OF
SNOW AFTER ABOUT 06Z FROM THE PORKIES UP THROUGH THE KEWEENAW
PENINSULA AS THE WINDS SHIFT TO THE WNW. HIGH RESOLUTION MODELS
AGREE FAIRLY WELL WITH THIS TIMING AND WILL BUMP POPS UP TO 100
PERCENT IN THOSE AREAS OVERNIGHT. WITH MUCH OF THE FORCING RIGHT
WITHIN AND A LITTLE ABOVE THE DGZ...SHOULD SEE FAIRLY DECENT SNOW
RATIOS (AROUND 20-22 TO 1) AND WOULD EXPECT AT LEAST OF COUPLE HOUR
PERIOD OF 1 IN/HR SNOWFALL AFTER 06Z IN SOME LOCATIONS.
THEREFORE...HAVE TRENDED THE SNOWFALL FORECAST UP A LITTLE BIT WITH
A GENERAL 1-3 INCH AMOUNTS AND HAVE THE HIGHEST VALUES OVER THE
HIGHER TERRAIN FROM THE PORKIES THROUGH THE KEWEENAW.
OVER THE REST OF THE CWA...WINDS WILL BE SHIFTING FROM
SOUTH-SOUTHEAST TO WESTERLY AS THE LOW MOVES TO THE EAST THROUGH
THE NIGHT. EXPECT THE ONGOING LAKE EFFECT OFF LAKE MICHIGAN TO
FOLLOW THAT EASTWARD PUSH THROUGH THE NIGHT AND LARGELY INFLUENCING
DELTA COUNTY IN THE EVENING AND THEN SCHOOLCRAFT AND SOUTHERN LUCE
COUNTIES DURING THE OVERNIGHT HOURS. THE EXPECTED EASTWARD MOVEMENT
OF THE LAKE ENHANCED SNOWFALL SHOULD LIMIT THE SNOWFALL AMOUNTS OVER
MOST OF THOSE AREAS TO A QUICK 1-3IN OF SNOW TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 403 AM EST SAT DEC 14 2013
NAM SHOWS A CLOSED 500 MB LOW NORTH OF LAKE SUPERIOR 12Z SUN WHICH
MOVES SOUTHEAST ON SUN. ANOTHER UPPER TROUGH DIGS SOUTHEAST INTO THE
AREA FOR MON NIGHT. NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE
12Z MON MOVING INTO THE AREA WITH SOME DEEPER MOISTURE WHICH REMAINS
INTO MON NIGHT. LAKE EFFECT SNOW WILL CONTINUE THIS PERIOD FOR
SUNDAY INTO SUNDAY EVENING WITH COLD AIR IN NORTHWEST AND NORTH LAKE
EFFECT SNOW BELTS. ON MONDAY...THERE COULD BE SOME LAKE ENHANCEMENT
MON AFTERNOON AND EVENING OFF OF LAKE MICHIGAN AND HAVE THIS COVERED
WITH LIKELY POPS IN THE EASTERN CWA FOR SOUTHWEST WIND FLOW. HAVE
LIKELY POPS MON NIGHT ACROSS THE KEWEENAW FOR WEST FLOW LAKE EFFECT
SNOW BELTS. DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR
TEMPERATURES.
IN THE EXTENDED...GFS AND ECMWF SHOW A BROAD 500 MB TROUGH OVER THE
CENTRAL AND EASTERN U.S. 12Z TUE. THIS TROUGH PULLS EAST 12Z WED
WITH SFC HIGH PRESSURE ALONG THE MISSISSIPPI RIVER VALLEY. SFC LOW
PRESSURE MOVES INTO THE CENTRAL PLAINS 12Z THU. GFS AND ECMWF SHOW A
500 MB TROUGH OVER THE NORTHERN PLAINS AND DESERT SW 12Z FRI. COLDER
THAN NORMAL TEMPERATURES LOOK TO CONTINUE THIS FORECAST PERIOD
EXCEPT FOR A BRIEF RESPITE ON THU INTO FRIDAY BEFORE COLD AIR
ARRIVES AGAIN. STILL LOOKS COLD ENOUGH WITH A WARM FRONT TO THE
SOUTH AND WARM AIR JUST TO THE SOUTH TO KEEP THE PCPN AS SNOW ON
THU...BUT WILL HAVE TO WATCH THIS AS THERE IS A LOW POSSIBILITY OF
SOME MIXED PCPN IN THE FAR SOUTH. BASICALLY...LAKE EFFECT SNOW WILL
CONTINUE THROUGH WED BEFORE SYSTEM KICKS OUT ON THU. COLD AIR THEN
ARRIVES AGAIN LATE ON FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1235 AM EST SAT DEC 14 2013
CMX...EXPECT PREDOMINANT VFR CONDITIONS UNTIL ABOUT SUNRISE...WHEN
THE VEERING LLVL WINDS ON THE SRN FLANK OF HI PRES MOVING ACRS
ONTARIO SHIFT TO THE E AND POSSIBLY ALLOW MORE -SHSN/MVFR CONDITIONS
TO IMPACT THIS LOCATION. AS THE FLOW CONTINUES TO VEER TO THE SE AND
THEN S...ANY LES SHOULD SHIFT TO THE N OF CMX BY LATE MRNG. THERE
MAY BE SOME -SN AS A DISTURBANCE APRCHS FM THE NW...BUT DOWNSLOPE
FLOW SHOULD RESULT IN VFR CONDITIONS. THE CLOSER APRCH OF SFC LO
PRES AND ATTENDANT COLD FNT LATE IN THE PERIOD MAY BRING A RETURN OF
HEAVIER SHSN/MVFR TO PERHAPS IFR CONDITIONS.
IWD...WITH DRY AND DOWNSLOPE E WIND VEERING TO THE S THRU THIS
PERIOD...VFR CONDITIONS SHOULD DOMINATE. SOME -SN MAY DEVELOP ON
SAT...BUT DOWNSLOPE NATURE OF THE PREVAILING FLOW SHOULD KEEP THE
LLVLS DRY ENUF FOR VFR CIGS/VSBYS. THE PASSAGE OF A COLD FNT AND
WSHFT TO THE WNW THIS EVNG WL BRING MORE SHSN/MVFR TO PERHAPS IFR
CONDITIONS.
SAW...EXPECT ANY LINGERING -SHSN TO SHIFT TO THE N OF SAW BY 06Z AS
THE LLVL FLOW VEERS TOWARD THE E. THEN WITH RELATIVELY DRY E TO SE
FLOW...VFR WX SHOULD THEN PREVAIL THRU THIS MRNG. SOME -SN IS LIKELY
TO DVLP ON SAT AFTN...AND SSE FLOW UPSLOPING OFF LK MI WL BRING
ABOUT MVFR CONDITIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EST SAT DEC 14 2013
HIGH PRESSURE OVER SOUTHERN ONTARIO EARLY THIS MORNING WILL MOVE
EAST INTO SOUTHWEST QUEBEC TODAY WHILE A LOW PRESSURE SYSTEM TAKING
SHAPE IN THE LOWER MISSISSIPPI VALLEY MOVES INTO THE MID ATLANTIC
STATES. WHILE THIS OCCURS...A LOW PRESSURE TROUGH WILL SETUP OVER
THE UPPER GREAT LAKES THIS AFTERNOON AND THEN DEVELOP INTO A WEAK
LOW TONIGHT BEFORE SHIFTING SOUTHEAST SUNDAY AFTERNOON INTO SUNDAY
NIGHT. EXPECT GENERALLY LIGHT WINDS ALONG THIS TROUGH TODAY AND
TONIGHT...BUT DO EXPECT THEM TO INCREASE OUT OF THE NORTHWEST ON
SUNDAY...WITH GUSTS TO 30KTS EXPECTED SUNDAY AFTERNOON/EVENING.
WINDS WILL QUICKLY DIMINISH LATE SUNDAY NIGHT BEFORE INCREASING OUT
OF THE SOUTHWEST ON MONDAY (GUSTS TO 30KTS) AHEAD OF A CLIPPER LIKE
LOW MOVING SOUTHEAST THROUGH SOUTHERN CANADA AND BRUSHING THE UPPER
GREAT LAKES ON MONDAY NIGHT AND TUESDAY. AS THE COLD FRONT SWEEPS
THROUGH ON MONDAY NIGHT...EXPECT WINDS TO SHIFT TO THE NORTHWEST
AND BE IN THE 20-30KT RANGE. THERE COULD EVEN BE SOME GALE FORCE
GUSTS TO 35KTS TUESDAY INTO TUESDAY NIGHT. ANOTHER QUICK HIGH
PRESSURE RIDGE WILL MOVE IN ON WEDNESDAY AND DIMINISH WINDS AHEAD
OF LOW DEVELOPING IN THE CENTRAL PLAINS AND EXPECTED TO MOVE
THROUGH THE GREAT LAKES REGION ON THURSDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 9 AM THIS MORNING TO 1 AM EST
SUNDAY FOR MIZ013.
LAKE EFFECT SNOW ADVISORY UNTIL 8 PM CST THIS EVENING FOR MIZ012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...07
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
313 AM CST Sat Dec 14 2013
.SHORT TERM...(Today through Sunday Night)
Issued at 313 AM CST SAT DEC 14 2013
Winter storm is departing the region early this morning. Lingering
areas of drizzle will cause some minor icing from eastern KS into
western and central MO through sunrise as temperatures continue to
drop below freezing. Additional snow amounts will be mostly confined
to areas around Boonville and Moberly where another inch or so is
possible through early morning. An additional band of light snow has
developed from Kansas City into Chillicothe and Kirksville in
response to a narrow band of frontogenesis. RAP and NAM hold on to
this frontogenetical forcing through about 12Z and drop it to near
I-70, so it`s conceivable for this area of snow to hold together for
a few more hours and produce a dusting of snow with local amounts up
to a half inch near and northeast of KC. With temperatures falling
below freezing, any light snow that falls may fall on top of ice
developing on roads as lingering water freezes. Will therefore keep
the advisory going through 9 am as planned.
Precipitation will taper off from northwest to southeast through mid
morning. There`s a slight chance for some flurries or freezing
drizzle to redevelop late this morning into early afternoon as the
main upper trough axis swings through and interacts with low-level
cold air advection. Anything that does fall through this period
should be very light if anything at all.
Clouds will begin to scatter out later this afternoon and evening
with low-level ridging building in from the west. This will allow
temperatures to drop well into the single digits across northern and
central MO where a decent snow pack exists. Temperatures will begin
to moderate by Sunday and Sunday night with conditions returning to
near average.
.LONG TERM...(Monday through Friday)
Issued at 313 AM CST SAT DEC 14 2013
Monday - Tuesday:
General troughing across eastern Canada and the northern Great Lakes
will keep the area under benign northwest flow aloft. Nearer the
surface, downsloping westerly flow will allow temperatures to climb
where there is no snowpack. Highs across east central Kansas and
west central Missouri will rise into the mid to upper 40s whereas
across north central Missouri, where there is snowpack, highs will
only reach the mid to upper 30s. Tuesday a weak cold front will drop
through the area however this will have little effect on
temperatures as highs Tuesday should again range in the upper 30s to
upper 40s.
Wednesday:
The upper level pattern begins to shift on Wednesday becoming more
zonal across the region. Surface winds will also increase out of the
south providing for WAA and highs will be in the upper 30s to near
50. The next feature of interest, in the form of an upper level
trough, will move into the southwestern CONUS.
Thursday - Friday:
Models are in a bit of disagreement this far in the extended range.
However, the ECMWF, GFS and GEM all show the upper level shortwave
moving into the western Plains on Thursday and forcing a strong cold
front towards the area. Warm moist air streaming out ahead of this
front may produce light rain or drizzle on Thursday as high
temperatures move above average into the mid 40s to mid 50s. Models
depict rain changing to snow behind the front as it moves through
the area on Thursday night. The model differences occur on Friday as
the GFS stalls the front south of the area with snow continuing
through the day Friday whereas, the EC builds high pressure into the
area keeping conditions dry. On Friday, left the chance POPs in the
grids inherited by the initialization to account for the GFS
solution.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1133 PM CST FRI DEC 13 2013
Light to moderate snow will continue to shift east out of the region
during the early morning hours, leaving behind some light drizzle and
patchy fog across the area. As temperatures fall over the next few
hours, freezing drizzle will be possible in areas mainly south of Hwy
36. Drier, colder air will work down from the north during the morning,
eventually helping ceilings to lift out of the LIFR category and also
bringing increased northerly winds in the 10 to 15 kt range. Stratus
is expected to scatter out from north to south during the early to
mid afternoon hours, leaving behind VFR conditions for the end of the
TAF period.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR KSZ025-
057-060-102>105.
MO...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR
MOZ004>008-012>017-020>025-028>033-037>040-043>046-053-054.
&&
$$
SHORT TERM...Hawblitzel
LONG TERM...73
AVIATION...Laflin
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1145 PM CST FRI DEC 13 2013
.UPDATE...
ISSUED AT 1144 PM CST FRI DEC 13 2013
SNOW HAS BRIEFLY ENDED IN THE NORTHWESTERN CWA SO CUT BACK POPS
DURING THE NEXT FEW HOURS. HOWEVER...MORE IS UPSTREAM AS SEEN ON
CANADIAN RADAR. NAM AND RAP SEEM TO HAVE A FAIRLY GOOD HANDLE ON
SNOW...SO WENT JUST FOR A BREAK IN THE NORTH DURING THE NEXT FEW
HOURS AND THEN HIGH POPS AGAIN AFTER 06Z TONIGHT. TEMPS CONTINUE
TO BE ON TRACK.
UPDATE ISSUED AT 927 PM CST FRI DEC 13 2013
MAIN ISSUE FOR THE UPDATE IS TEMPS AND THE WIND CHILLS. TEMPS SEEM
ON TRACK TO DROP INTO THE TEENS BELOW ZERO IN THE NORTH TO NEAR
ZERO IN THE SOUTH. WINDS WILL CONTINUE TO DIMINISH...AND MOST
LOCATIONS ARE ALREADY BELOW WIND CHILL CRITERIA. THE EXCEPTION IS
IN THE DEVILS LAKE AREA...BUT WITH WINDS CONTINUING TO GO DOWN
THINK THIS WILL NOT LAST MUCH LONGER THAN AN HOUR OR TWO. LET THE
WIND CHILL ADVISORY EXPIRE ON TIME AT 9 PM. HIGH POP/LOW QPF SNOW
LOOKS LIKE IT WILL CONTINUE...SO MADE ONLY MINOR TWEAKS TO POPS.
UPDATE ISSUED AT 629 PM CST FRI DEC 13 2013
MADE ONLY A FEW MINOR TWEAKS TO POPS AS VERY LIGHT SNOW CONTINUES
TO BE REPORTED IN PORTIONS OF THE WESTERN AND SOUTHERN CWA. THINK
THAT THE HIGH POP/LOW QPF SITUATION CONTINUES TO SEEM VALID. TEMPS
WILL CONTINUE TO DROP INTO THE TEENS BELOW ZERO...AND WE SHOULD
SEE WINDS FALL OFF LATER TONIGHT AND THE WIND CHILL THREAT
DIMINISH.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 316 PM CST FRI DEC 13 2013
THE BAND OF SNOW WHICH PRODUCED AN INCH OR TWO OF FRESH SNOW LAST
NIGHT INTO THIS MORNING ROUGHLY FROM SOUTHEASTERN SASK THROUGH
DEVILS LAKE REGION TO THE MID RED RIVER VALLEY IS WEAKENING THOUGH
SOME LIGHT SNOW WILL CONTINUE IN THE FAR WEST AND SOUTHWESTERN
FCST AREA THIS EVE. NEXT SHORT WAVE SEEN OVER EAST CENTRAL ALBERTA
ON WATER VAPOR IS PRODUCING SNOW IN CENTRAL SASK WHERE 10-15 CM
ARE EXPECTED. THIS AREA OF SNOW WILL DROP SOUTHEAST INTO NE ND/FAR
NW MN NR 06Z AND SPREAD EAST-SOUTHEAST INTO SATURDAY MORNING. THE
LIGHT SNOW WILL END IN ERN ND SAT MORNING AND NW MN SAT AFTN.
COORD WITH NEIGHBORS AND ALL AGREED WITH THE HIGH POP/LOW QPF
ANGLE SO HAVE HIGH POPS TONIGHT INTO SATURDAY MORNING. SIMILAR
AMOUNTS TO THIS PAST WAVE WITH MOST AREAS AN INCH OR LESS WITH
POCKETS OF 2 INCHES..ESP IT SEEMS VIA HPC QPF IN NORTHEASTERN ND.
THE BEST LOW LEVEL COLD ADVECTION DOES END THIS EVENING AND AS
WAVE COMES DOWN OVERALL DONT EXPECT A BIG FALL TONIGHT TEMP WISE.
WINDS WILL LIGHTEN OVERNIGHT AS PUSH OF COLD AIR EASES AND WINDS
4 KTS OR LESS AND NOT ENOUGH TO PUSH WIND CHILL VALUES INTO THE
ADVISORY RANGE PAST ABOUT 05Z. THUS WILL LET CURRENT WIND CHILL
ADV EXPIRE ON TIME AT 03Z. COULD BE A 1-3 HOUR PERIOD WITH A FEW
SITES IN ADVISORY RANGE ON THE LOW END BUT NOT NOTEWORTHY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 316 PM CST FRI DEC 13 2013
NEXT 500 MB SHORT WAVE SEEN WEST OF JUNEAU ALASKA WILL MOVE
SOUTHEAST SUNDAY INTO MONDAY. THIS WILL MAINLY GO A BIT
NORTH...BUT WARM ADVECTION PRETTY STRONG AND EXPECT A BAND OF
LIGHT SNOW TO AGAIN SPREAD OVER THE AREA LATE SAT NIGHT IN THE FAR
WEST AND SUNDAY ELSEWHERE WITH UP TO 1 INCH OF NEW SNOWFALL. VERY
TIGHT TEMP GRADIENT EXPECTED WITH A BREEZY SOUTH WIND LIKELY TO
DEVELOP SAT NIGHT AND CONTINUE INTO SUNDAY EAST OF SURFACE
TROUGH/WARM FRONT WHICH 12Z SUN WILL BE IN CNTRL ND. QUITE COLD
STILL EAST OF FRONT....BUT AS OFTEN THE CASE LOOK FOR TEMP RISE TO
COINCIDE WITH PASSAGE OF TROUGH/WARM FRONT SUN MIDDAY-AFTN AND A
WIND SHIFT TO THE WEST. 850 MB TEMPS WARMEST 12Z-18Z SUN THEN
COOL...BUT COLD AIR ADVECTION AT SURFACE LAGS ABOUT 6 HOURS...SO
DO EXPECT MILD TEMPS INTO SUN EVE IN THE SOUTH BEFORE COLD AIR
DROPS BACK SOUTH. KEPT IDEA OF MID TO UPPER 20S EAST OF THE RED
RIVER VALLEY AND AROUND 30 IN THE RED RIVER VALLEY AND LOWER 30S
OR PSBLY MID 30S HIGHER TERRAIN WEST OF THE RED RIVER VALLEY...ESP
AREAS CLOSER TO THE SOUTH DAKOTA BORDER.
PRECIPITATION CHANCES FOR THE FIRST HALF OF THE WEEK ARE ESSENTIALLY
NIL AS THE TRAIN OF WEAK DISTURBANCES CONTINUES TO MOVE THROUGH
NORTHWEST FLOW ALOFT. A FORECAST OF SNOW FORECAST BECOMES
MORE TO RECKON WITH LATE WEDNESDAY INTO THURSDAY AS MODELS SHOW A
LARGE TROUGH DIGGING INTO THE GREAT BASIN AND DESERT SOUTHWEST.
MORE TO THE DETAILS...GFS IS PORTRAYING NORTHWEST FLOW REGIME WITH
A DEFINED HYBRID TYPE CYCLONIC SYSTEM MOVING INTO UPPER MIDWEST
DURING THURSDAY. INVERTED TROUGH SEEMS TO BE FOCUSED OVER
NORTHEAST CWA WHERE MOST ACTIVE WEATHER WOULD BE LIKELY. AFTER THAT
JUST MORE ARCTIC COLD FOR FRIDAY AS H1000-500 THICKNESSES DROP BELOW
500 HPA ONCE MORE. ECMWF IN AGREEMENT WITH RESPECT TO A SYSTEM FOR
THURSDAY BUT IT IS MORE DIFFUSE IN NATURE. POPS ARE HIGHEST DURING
THIS PERIOD...IN THE CHC CATEGORY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1144 PM CST FRI DEC 13 2013
VFR CIGS WILL CONTINUE...ALTHOUGH A SNOW BAND OVER KFAR HAS KEPT
VIS BOUNCING BETWEEN 1 AND 2SM. THAT BAND WILL MOVE SOUTH...BUT
ANOTHER ROUND OF LIGHT SNOW WILL MOVE IN FROM THE NORTHWEST. THINK
THAT VIS WILL BE AROUND 3 TO 5SM WITH CIGS IN THE MVFR CATEGORY.
THE LIGHT SNOW AND LOWER CIGS WILL LINGER INTO THE MORNING HOURS
BEFORE MOVING OFF TO THE EAST. VFR CONDITIONS SHOULD RETURN BY
AFTERNOON. WINDS WILL BE LIGHT AND VARIABLE BEFORE PICKING UP A
BIT OUT OF THE NORTHWEST BY THE END OF THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...RIDDLE
LONG TERM...WJB/RIDDLE
AVIATION...JR
AREA FORECAST DISCUSSION
NWS NORMAN OK
338 AM CST SAT DEC 14 2013
.DISCUSSION...
WARMER WEATHER OVER THE NEXT SEVERAL DAYS WILL BE THE MAIN WEATHER
STORY.
DENSE FOG ADVISORY ACROSS MAINLY SOUTHERN OKLAHOMA IS IN OKAY
SHAPE...THOUGH VISIBILITIES HAVE BEEN INCREASING RAPIDLY DUE TO
INCREASING LOW LEVEL WINDS AND COLD AIR ADVECTION BEHIND A COLD
FRONT THAT WAS NEAR A WAURIKA TO SEMINOLE LINE AT 330 AM. THE
ADVISORY GOES UNTIL 6 AM THIS MORNING AND MAY BE CANCELLED BEFORE
THEN AS VISIBILITIES SHOULD CONTINUE TO IMPROVE.
KEPT PATCHY DRIZZLE/PATCHY FREEZING DRIZZLE THIS MORNING EAST OF
I-35 AS LATEST RADARS INDICATED LIGHT ECHOES EAST OF WICHITA AND
NEAR TULSA. LATEST HRRR RUNS AND THE RADAR DATA SHOW THAT SOME OF
THIS VERY LIGHT PRECIPITATION MAY AFFECT LOCATIONS EAST OF I-35.
NO PROBLEMS ARE EXPECTED AS THE PRECIPITATION WOULD BE VERY LIGHT
AND MOST LIKELY EVAPORATE ON SURFACES DUE TO THE BRISK NORTH
WINDS.
TODAY WILL BE A BRISK AND COLDER DAY. CLOUDS WILL ERODE WEST TO
EAST WITH THE CLEARING LINE NEAR I-35 AROUND NOON. MODEL GUIDANCE
HIGHS IN THE MID 30S EAST OF I-35 TO THE UPPER 40S ACROSS FAR
WESTERN NORTH TEXAS WERE ACCEPTED.
TONIGHT...CLEAR AND SEASONABLY COLD CONDITIONS WILL OCCUR WITH
LOWS MAINLY IN THE 20S.
SUNDAY WILL BE SUNNY AND WARMER. THINK HIGHS WILL GET IN THE 50S
AREAWIDE...AND PERHAPS ABOVE 60 DEGREES ACROSS PARTS OF WESTERN
OKLAHOMA AND WESTERN NORTH TEXAS.
SUNDAY NIGHT THROUGH THURSDAY...A PERIOD OF WARM AND DRY CAN BE
EXPECTED. TEMPERATURES WILL GENERALLY BE 5 TO 15 DEGREES ABOVE
AVERAGE. HIGHS MAY GET ABOVE 70 DEGREES IN A FEW LOCATIONS.
THURSDAY NIGHT INTO FRIDAY...CONFIDENCE IS GROWING THAT MUCH
COLDER AIR WILL RETURN TO THE AREA WITH AN ARCTIC COLD FRONT.
WINTRY PRECIPITATION MAY RESULT. PRECIPITATION TYPES...
LOCATIONS...AND AMOUNTS REMAIN VERY UNCERTAIN. FOR NOW...KEPT LOW
PRECIPITATION CHANCES ACROSS THE AREA MAINLY ON FRIDAY.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 37 26 58 31 / 0 0 0 0
HOBART OK 43 25 56 27 / 0 0 0 0
WICHITA FALLS TX 46 26 61 30 / 0 0 0 0
GAGE OK 47 21 59 23 / 0 0 0 0
PONCA CITY OK 38 24 56 27 / 0 0 0 0
DURANT OK 40 28 53 33 / 0 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
OKZ028>032-039>043-045>048-050>052.
TX...DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR TXZ090.
&&
$$
25/17
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1132 PM CST FRI DEC 13 2013
.AVIATION...
FOR THE 06Z TAFS...NO SIGNIFICANT CHANGES FROM THE OVERALL
THINKING OF THE 00Z TAFS...SO THE PREVIOUS DISCUSSION HAS BEEN
LEFT APPENDED BELOW.
THE BIGGEST CHANGE WITH THE 06Z TAFS WAS TO LOWER VISIBILITIES OUT
AHEAD OF THE COLD FRONT. AREAS OF DENSE FOG WERE DEVELOPING OVER
MANY PARTS OF NORTH AND CENTRAL TEXAS...AND WILL LIKELY DEVELOP AT
AREA AIRPORTS BEFORE THE FRONT ARRIVES AT 10Z. LOWERED VSBYS THE
MOST AT KFTW AND KAFW AS IR SATELLITE OBSERVED MOSTLY CLEAR SKIES
OVER THESE SITES. FOR THE REMAINDER OF THE DFW AREA TAFS CONTINUE
TO FORECAST A DROP IN VSBYS AFTER MIDNIGHT. KDFW AND KDAL WERE
STILL REPORTING MVFR SURFACE VSBYS IN THE REMARKS OF THEIR
OBSERVATIONS...WHICH IS WHY THE TAFS START OUT THAT WAY DESPITE
VSBYS THAT LOOK LOWER IN THE ACTUAL OBSERVATION. KACT WAS ALREADY
SURROUNDED WITH DENSE FOG...AND THIS IS UNLIKELY TO CHANGE UNTIL
THE FRONT ARRIVES AT 12Z.
CAVANAUGH
.../PREVIOUS AVIATION DISCUSSION/...
FOR THE 00Z TAFS...FLIGHT CATEGORY RESTRICTIONS ASSOCIATED WITH AN
APPROACHING COLD FRONT AND ONGOING LIGHT RAINFALL ACROSS THE
REGION ARE THE PRIMARY FORECAST CONCERNS.
23 TO 00Z OBSERVATIONS WERE HOVERING AROUND HIGH IFR TO LOW MVFR
CONDITIONS ACROSS THE DFW METROPLEX. OPTED TO GO WITH IFR CIGS
WITH MVFR VSBYS TO START OFF THE TAFS AS FORECAST SOUNDINGS ALL
SHOW CIGS LOWERING FROM 00 TO 03Z. LIGHT RAINFALL WILL LIKELY
PERSIST THROUGH MIDNIGHT BEFORE DRY AIR STARTS TO BUILD OVER THE
REGION BEHIND AN EXITING UPPER LEVEL DISTURBANCE. LIGHT
RAIN/DRIZZLE CONCERNS THROUGH MIDNIGHT PROMPTED THE CONTINUATION
OF THE MVFR VSBYS FOR THE START OF THE FORECAST.
SURFACE LOW PRESSURE IS EXPECTED TO SWEEP EAST ACROSS THE REGION
JUST OUT AHEAD OF A COLD FRONT. THIS WILL CAUSE WINDS TO VEER AND
DROP IN INTENSITY FOR A FEW HOURS BEFORE THE COLD FRONT ARRIVES.
THIS DROP IN WIND SPEEDS MAY ALLOW FOR SOME SHALLOW GROUND FOG TO
DEVELOP...SO WENT AHEAD WITH IFR VSBYS FOR THE WINDOW IN BETWEEN
MIDNIGHT AND WHEN THE FRONT IS EXPECTED TO ARRIVE...OR AROUND 10Z.
FORECAST SOUNDINGS INDICATE IFR CIGS AND ARE INCONCLUSIVE ON FOG
POTENTIAL. THE RAP AND LAMP GUIDANCE CERTAINLY HIT THE FOG
POTENTIAL HARD...BUT WITH LOW STRATUS IN PLACE...RADIATIONAL
COOLING WILL BE STUNTED WHICH SHOULD GENERALLY PREVENT DENSE FOG
FROM DEVELOPING AROUND AREA AIRPORTS AFTER MIDNIGHT. AT THIS POINT
WILL WAIT AND SEE IF IT LOOKS LIKE SHALLOW/GROUND FOG IS GOING TO
BE MORE EXPANSIVE TONIGHT...IF SO WILL HIT THE FOG POTENTIAL AND
VISIBILITIES HARDER AT THE 03 OR 06Z TAF ISSUANCES.
BEHIND THE FRONT...WINDS ARE EXPECTED TO BE STRONG ENOUGH TO CAUSE
ANY FOG THAT MANAGES TO DEVELOP TO DISSIPATE QUICKLY. WENT AHEAD
WITH VFR VSBYS AFTER THE FRONTAL PASSAGE AS A RESULT. CIGS WILL
REMAIN IFR RIGHT AFTER THE FRONTAL PASSAGE...AND WILL RISE TO MVFR
AND EVENTUALLY VFR BY TOMORROW AFTERNOON AS DRIER AIR WORKS INTO
THE REGION.
CAVANAUGH
&&
.UPDATE...
WILL UPDATE FOR PATCHY DENSE FOG IN AREAS EAST OF A LINE FROM
LAMPASAS TO GRANBURY TO BOWIE...AND ISSUE ADVISORY. WILL ALSO END
THE PRECIP AT 10 PM BASED ON EXTRAPOLATION OF CURRENT SHOWERS IN
THE EAST. IN AREAS WITH ICE...THE 40 DEW POINT AIR AND THE 30
DEGREE ICE WILL AID IN FOG FORMATION...AND MANY OTHER AREAS JUST
RECEIVED RAIN WHICH WILL ALSO AID IN FOG FORMATION. THE FRONT
SHOULD INCREASE VISIBILITY STARTING BEFORE SUNRISE FROM NORTHWEST
TO SOUTHEAST. THE HEAT ISLAND WILL ALSO LIKELY KEEP VISIBILITIES
ABOVE ADVISORY CRITERIA IN THE MIDDLE OF THE DFW METROPLEX.
UPDATE OUT SHORTLY. 84
&&
.PREV DISCUSSION... /ISSUED 349 PM CST FRI DEC 13 2013/
WATER VAPOR LOOP SHOWS A WELL DEFINED SHORTWAVE MOVING INTO THE
TEXAS PANHANDLE NOW. NORTH TEXAS IS CURRENTLY LOCATED IN A REGION
OF STRONG LIFT...BUT DEEPER MOISTURE IS ALREADY BEING SHUNTED EAST
OF THE AREA AS A DRY SLOT ALOFT WORKS THROUGH FROM THE SOUTHWEST.
HOWEVER THE LOW LEVELS REMAIN MOIST AND SATURATED AND THIS LIFT
WILL CONTINUE TO RESULT IN SCATTERED LOW TOPPED SHOWERS AND PATCHY
DRIZZLE OVER THE NEXT FEW HOURS. MUCH OF THIS ACTIVITY WILL END AS
THE BEST LIFT MOVES EAST OF THE CWA...AND FIRST PERIOD POPS WHICH
BEGIN AFTER 6PM WILL BE ON THE LOW SIDE FOR THE CENTRAL/WESTERN
CWA. A SECOND STRONG SHORTWAVE RIGHT ON THE HEELS OF THE FIRST
WILL APPROACH THE AREA LATE TONIGHT WHICH WILL ENSURE SOUTHERLY
WINDS THIS EVENING AND WARM/MOIST ADVECTION NEAR OR JUST ABOVE THE
SURFACE. THE WINDS AND WARM ADVECTION WILL LIKELY LIMIT THE
POTENTIAL FOR FOG TONIGHT...DESPITE A VERY FAVORABLE PROFILE...BUT
MAY ENHANCE THE POTENTIAL FOR LOW CLOUDS AND DRIZZLE. TEMPS WILL
LIKELY REMAIN NEARLY STEADY TONIGHT IN THE 40S AHEAD A COLD FRONT.
A SURFACE LOW AND COLD FRONT WILL MOVE THROUGH NORTH TEXAS AFTER 3
AM WITH WINDS BECOMING NORTH AT 15 MPH BY SUNRISE. STRONG
FRONTOGENETIC LIFTING OF A SATURATED LAYER NEAR THE SURFACE WILL
RESULT IN WIDESPREAD LOW CLOUDS AND SOME DRIZZLE BEHIND THE FRONT
SATURDAY MORNING. CLOUDS WILL CLEAR FROM NORTHWEST TO SOUTHEAST
DURING THE MID-LATE AFTERNOON HOURS ON SATURDAY. DUE TO THE CLOUDS
AND COLD ADVECTION BEHIND THE FRONT HIGHS SATURDAY WILL LIKELY
REMAIN IN THE LOW TO MID 40S. HOWEVER RADIATIONAL COOLING LOOK
GOOD SATURDAY NIGHT WITH LOWS FALLING INTO THE 20S AREA WIDE.
A GRADUAL MODERATION IN TEMPERATURES IS EXPECTED SUNDAY INTO THE
MIDDLE OF NEXT WEEK. GENERALLY CLEAR SKIES AND DRY AIR WILL ALLOW
FOR WARMER/MILD DAYS AND COOL NIGHTS. HIGHS SUNDAY WILL BE IN THE
50S FOR MOST AREAS...BUT 60S ARE EXPECTED MONDAY AND BEYOND. BY
WEDNESDAY SOUTHERLY WINDS WILL INCREASE AND BEGIN TO BRING HIGHER
DEWPOINTS INTO THE AREA WITH LOWS WELL ABOVE NORMAL IN THE 50S.
MEANWHILE...ANOTHER ARCTIC AIRMASS WILL BE GATHERING ACROSS CANADA
AS A POLAR VORTEX TRACKS FROM SIBERIA...ACROSS THE NORTH
POLE...AND INTO THE HUDSON BAY AREA BY NEXT WEEKEND. THIS UPPER
LEVEL PATTERN WILL RESULT IN ANTI-CYCLOGENESIS AND THE DEVELOPMENT
OF AN INTENSE ARCTIC HIGH PRESSURE CELL THAT DROPS INTO THE PLAINS
BY THURSDAY. THIS FRONT WOULD LIKELY TRACK THROUGH NORTH TEXAS ON
FRIDAY WITH TEMPERATURES AGAIN FALLING TO WELL BELOW NORMAL NEXT
WEEKEND. WE HAVE SEEN THE MODELS WAFFLE A BIT ON JUST HOW COLD
THIS AIRMASS WILL BE OVER THE LAST FEW DAYS FOR NORTH TEXAS. WHILE
THIS WILL SURELY BE ANOTHER NOTEWORTHY COLD SNAP FOR MUCH OF THE
COUNTRY...AS FAR AS NORTH TEXAS IS CONCERNED...THE MODELS ARE NOT
FORECASTING AN UPPER LEVEL PATTERN THAT WOULD RESULT IN ANY TYPE
OF RECORD BREAKING COLD HERE. AT THIS POINT I DONT SEE ANY
COMPELLING REASON TO BELIEVE THIS WILL BE ANY COLDER THAN OUR LAST
ARCTIC SPELL. THIS IS BECAUSE ALL MODELS HAVE BEEN VERY CONSISTENT
ON STRONG SURFACE LOW CYCLOGENESIS ACROSS THE PLAINS AND GREAT
LAKES WHICH WILL SERVE TO KEEP THE UPPER LEVEL LONGWAVE TROUGH
MORE PROGRESSIVE. PROGRESSIVE LONGWAVE TROUGHS DONT LET AS MUCH
COLD AIR DROP THIS FAR SOUTH AS SLOW MOVING OR STATIONARY UPPER
TROUGHS DO. ESSENTIALLY IN THIS UPPER LEVEL PATTERN...THE CORE OF
THE COLD AIR ENDS UP HEADING MORE EAST THAN SOUTH ONCE IT ARRIVES
INTO THE PLAINS AND MIDWEST.
CONCERNING WINTER PRECIP POTENTIAL...THERE IS STILL A TREMENDOUS
AMOUNT OF UNCERTAINTY WITH THE SHORTER WAVELENGTH FEATURES THAT
WOULD POSSIBLY PROVIDE THE LIFT AND MOISTURE REQUIRED FOR POST
FRONTAL WINTER PRECIP. IT WILL CERTAINLY BE COLD ENOUGH OVER NORTH
TEXAS FOR WINTER PRECIP AND LIKELY SNOW BY SATURDAY. THE KEY AT
THIS POINT IS VERY WEAK SHORTWAVE TROUGH THAT IS CURRENTLY OVER
JAPAN. THIS SYSTEM IS FORECAST TO REMAIN A RATHER INNOCUOUS POCKET
OF POTENTIAL VORTICITY FOR THE NEXT SEVERAL DAYS AS IT TRACKS
ACROSS THE PACIFIC...BUT IS FORECAST TO AMPLIFY/INTENSIFY AS IT
ARRIVES INTO THE PACIFIC NORTHWEST WEDNESDAY AND THURSDAY. THE 12Z
GFS/CANADIAN PHASE THIS ENERGY INTO THE BROADER LONGWAVE TROUGH...
AND SUGGEST ALL PRECIP WILL END BEFORE THE AIR GETS COLD ENOUGH
FOR SNOW. THE ECMWF AND SEVERAL GFS ENSEMBLE MEMBERS INDICATE
THAT THE ENERGY WITH THIS SYSTEM WILL REMAIN DETACHED FROM THE
MAIN UPPER TROUGH AND FORM INTO A CLOSED UPPER LOW WHICH TRACKS
OVER THE REGION SATURDAY. THIS SOLUTION WOULD RESULT IN A CHANCE
OF SNOW...ESPECIALLY OVER THE NORTHWEST/NORTHERN ZONES SATURDAY.
RIGHT NOW BASED ON ALL ENSEMBLE AND AVAILABLE OPERATIONAL RUNS WE
WOULD ESTIMATE THE CHANCE OF SNOW IN PART OF OUR CWA NEXT
SATURDAY AT 20 PERCENT. OF COURSE AT THIS TIME RANGE THERE IS
PLENTY OF TIME FOR MODELS TO TREND IN EITHER DIRECTION...SO WE
WILL HAVE TO WAIT AND SEE.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 40 43 29 54 35 / 10 10 0 0 0
WACO, TX 38 45 28 55 30 / 10 10 0 0 0
PARIS, TX 37 43 26 49 31 / 20 10 0 0 0
DENTON, TX 39 43 24 54 30 / 10 10 0 0 0
MCKINNEY, TX 39 42 25 52 28 / 20 10 0 0 0
DALLAS, TX 40 42 30 53 37 / 10 10 0 0 0
TERRELL, TX 40 43 27 52 30 / 20 10 0 0 0
CORSICANA, TX 41 44 28 53 34 / 20 10 0 0 0
TEMPLE, TX 39 46 29 56 30 / 10 10 0 0 0
MINERAL WELLS, TX 37 44 25 58 30 / 5 10 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 8 AM CST SATURDAY FOR TXZ091>095-
102>107-117>123-131>135-143>148-156>162-174-175.
&&
$$
/
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
230 AM CST SAT DEC 14 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 230 AM CST SAT DEC 14 2013
TWO AREAS OF PCPN TO WATCH TODAY.
FIRST...THE ONE ACROSS IOWA/ILL THAT IS BEING DRIVEN BY AN UPPER
LEVEL SHORTWAVE TROUGH SPINNING TOWARD THE OH RIVER VALLEY. RADAR
AND MESO MODEL TRENDS ON THIS PCPN REGION ARE TO KEEP IT JUST SOUTH
OF THE FORECAST AREA.
SECOND...AREAS OF SNOW ACROSS MUCH OF MN/NORTHERN PLAINS TRACKING
EAST SOUTHEAST...WITH SOME LOW LEVEL THERMODYNAMIC FORCING AND A
SHORTWAVE TROUGH DROPPING SOUTH OUT OF SOUTHERN CANADA HAVING A HAND
IN ITS PRODUCTION. THIS WILL BE THE SNOW THAT FALLS ACROSS THE
FORECAST AREA TODAY...LIKELY LINGERING INTO THE EVENING HOURS AS THE
SHORTWAVE MAKES IT WAY ACROSS THE UPPER MISSISSIPPI RIVER VALLEY.
GENERALLY...IT LOOKS LIKE UP TO AN INCH OF FLUFFY ACCUMULATIONS FOR
MOST LOCATIONS...BUT UP TO 2 INCHES NORTH/EAST OF I-94 WHERE THE
SHORTWAVE INFLUENCE WILL BE FELT LONGER.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 230 AM CST SAT DEC 14 2013
A COUPLE UPPER LEVEL SHORTWAVES WILL TAKE AIM ON THE REGION AS THE
BUSY NORTHWEST FLOW CONTINUES. DECENT AGREEMENT BETWEEN THE
NAM/GFS/EC WITH SLIDING A BIT OF UPPER LEVEL ENERGY ACROSS MN/IA
SUNDAY NIGHT...WITH A STRONGER SHORTWAVE MOVING OVER NORTHERN WI
MONDAY AFTERNOON/NIGHT. LIGHT SNOW WOULD BE LIKELY WITH THESE UPPER
LEVEL FEATURES...BUT TIMING/POSITIONING IS PROBLEMATIC. WILL SIDE
WITH HIGH CHANCES FOR SNOW FOR NOW.
THE GFS AND ECMWF HAVE BEEN AT ODDS AT HOW TO HANDLE AN END OF THE
WORK WEEK LOW PRESSURE SYSTEM...BUT THEY ARE STARTING TO SHOW MORE
COMPATIBILITY WITH THEIR RECENT SOLUTIONS. TRENDS ARE FAVORING THE
FASTER...MORE NORTH SOLUTION THAT THE EC HAD BEEN ALLUDING TO...WITH
AN UPPER LEVEL SHORTWAVE SPINNING OUT OF THE SOUTHERN ROCKIES...TO
ACROSS THE SOUTHERN GREAT LAKES BY TOWARD 00Z FRI. THE ACCOMPANYING
SFC LOW TRACKS INTO SOUTHERN WI BY THIS TIME. STRONG SLUG OF LOW
LEVEL WARM AIR ADVECTION AND ISENTROPIC UPGLIDE AHEAD OF THE
SHORTWAVE. GOOD PUSH OF LOW LEVEL MOISTURE ADVECTION ALSO INDICATED
AS A 50 KT 850 MB JET POINTS INTO THE SOUTHERN GREAT LAKES. AMPLE
THERMODYNAMICS FOR PCPN PRODUCTION ON THU...WITH THE SHORTWAVE
ENHANCING THE PCPN BY 00Z FRI. CURRENT TRENDS WOULD SHIFT THE SYSTEM
TO THE EAST/NORTHEAST BY 12Z FRI.
OF INTEREST WITH THIS PCPN MAKER IS THAT PCPN TYPE WILL BE A
CONCERN. LATEST TIME/HEIGHT X-SECTIONS AND BUFKIT SOUNDINGS INDICATE
BOTH A NEAR SFC WARM LAYER...AND SHALLOW SATURATION ON THE FRONT END
OF THE LOW PRESSURE SYSTEM. BOTH WOULD RESULT IN LIQUID...AND
DEPENDING ON SFC TEMPS...SOME FREEZING PCPN COULD RESULT. SPEED/
TIMING/POSITIONING OF THE SYSTEM PUTS ACCUMULATING SNOWS IN QUESTION
TOO...AS IT MIGHT BE TOO WARM AND DOESN/T LINGER LONG ENOUGH FOR
COLD AIR TO WORK IN. GOING TO STICK WITH RAIN OR SNOW FOR PTYPES
NOW.
THE SYSTEM BEARS WATCHING MORE FOR THE PCPN TYPES RATHER THAN
AMOUNTS.
HIGH PRESSURE IS THE SLATED TO BUILD IN FROM THE PLAINS BY FRIDAY
NIGHT...STICKING AROUND ON SAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1123 PM CST FRI DEC 13 2013
THE BAND OF MVFR CLOUDS MOVED BACK OVER BOTH TAF SITES AS EXPECTED
THIS EVENING AND NOW LOOKS LIKE IT WILL REMAIN THROUGH THE PERIOD.
THE THREAT FOR SOME SNOW WILL COME FROM THE SHORT WAVE TROUGH
APPROACHING FROM THE WEST. LIGHT SNOW IS FALLING AHEAD OF THIS WAVE
FROM WESTERN MINNESOTA INTO WISCONSIN WEST OF THE TWIN CITIES. AS
THE WAVE CONTINUES TO MOVE EAST...LOOK FOR THE LIGHT SNOW TO SLOWLY
MOVE SOUTHEAST AND SPREAD OVER THE TAF SITES DURING THE OVERNIGHT
HOURS. CONDITIONS ARE QUITE VARIABLE WITH THE SNOW...BUT ARE
PRIMARILY MVFR WITH SOME LOCATIONS REPORTING IFR CONDITIONS. THIS
CORRESPONDS WELL TO THE 14.00Z NAM AND 14.03Z RAP BUFKIT SOUNDINGS
FOR BOTH SITES AND WILL SHOW PREVAILING MVFR CONDITIONS IN THE LIGHT
SNOW WITH A PERIOD OF IFR POSSIBLE LATE TONIGHT INTO EARLY SATURDAY
MORNING. ONCE THE FORCING FROM THE MAIN WAVE MOVES PAST...THE NAM
SUGGEST SOME WEAK FRONTOGENESIS IN THE 1000-850 MB LAYER WILL LINGER
OVER EASTERN MINNESOTA INTO THE DAY AS THE NEXT NORTHERN STREAM
SHORT WAVE TROUGH MOVES ACROSS THE REGION. WILL THUS KEEP A MVFR
VISIBILITY INTO THE AFTERNOON BEFORE GOING TO FLURRIES AS THE
FRONTOGENESIS WEAKENS BY MID AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION.....04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1123 PM CST FRI DEC 13 2013
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 205 PM CST FRI DEC 13 2013
WATER VAPOR LOOP/LATEST RUC 500MB ANALYSIS SHOWS A BROAD LONG WAVE
TROUGH ENCOMPASSING THE ENTIRE CONUS. WITHIN THIS LONG WAVE TROUGH
THERE ARE TWO MID-LEVEL SHORTWAVE TROUGHS THAT WILL EVENTUALLY
IMPACT THE AREA TONIGHT THROUGH SATURDAY EVENING. TROUGH NUMBER ONE
WAS MOVING EAST OUT OF MT/WY TOWARD THE NORTHERN PLAINS WHILE A MORE
POTENT TROUGH NUMBER TWO WAS MOVING EAST OUT OF CO/NM INTO THE
SOUTHERN PLAINS. AT THE SURFACE...THIS TRANSLATED TO AN AREA OF
CYCLOGENESIS OVER WESTERN KS WITH A WARM FRONT EXTENDING ALONG THE
IA/MO BORDER INTO CENTRAL IL. CURRENTLY...OUR LOCAL FORECAST AREA
WAS IN BETWEEN THE INFLUENCES OF THE SOUTHERN PLAINS LOW AND HIGH
PRESSURE OVER SOUTHERN MANITOBA CANADA WITH EAST WINDS AND MOSTLY
CLOUDY CONDITIONS RESULTING. TEMPERATURES THIS AFTERNOON RANGED FROM
THE TEENS ACROSS NORTH CENTRAL WI...TO THE LOWER AND MIDDLE 20S
ELSEWHERE.
WILL BE WATCHING THE SOUTHERN PLAINS AND NORTHERN PLAINS TROUGHS
CONVERGE ON THE AREA LATE TONIGHT INTO SATURDAY. NOT PARTICULARLY
STRONG DYNAMICS ASSOCIATED WITH THESE WAVES. HOWEVER...THE AREA WILL
BE IN LONG-LIVED RIGHT ENTRANCE REGION OF 300MB JET WHILE THERE IS
SOME WEAK ISENTROPIC UPGLIDE NOTED ON THE NAM 275K SURFACE.
ALSO...THERE IS A DECENT PASSING LOBE OF 700-300 PV-ADVECTION FROM
ABOUT 12Z-18Z SATURDAY. ALL THIS IS EXPECTED TO COME TOGETHER TO
PRODUCE A FAIRLY WIDESPREAD AREA OF LIGHT SNOW WITH THE PEAK
CENTERED FROM ABOUT 09Z-15Z...THEN TAPERING OFF IN THE
AFTERNOON/SATURDAY EVENING AS THE TROUGH AXIS PASSES AND SUBSIDENCE
TAKES OVER. SOME VERY LIGHT SNOW/FLURRIES WILL BE POSSIBLE THROUGH
MIDNIGHT SATURDAY NIGHT BEFORE FULL SUBSIDENCE KICKS IN...DRYING
THINGS OUT. APPEARS AT THIS TIME THERE IS THE POTENTIAL FOR 1/2 UP
TO 2 INCHES OF SNOWFALL OUT OF THIS FROM TONIGHT THROUGH SATURDAY
EVENING. TEMPERATURE-WISE... LOOK FOR LOWS TONIGHT IN THE SINGLE
DIGITS AND TEENS...HIGHS ON SATURDAY IN THE UPPER TEENS TO MIDDLE
20S...AND LOWS SATURDAY NIGHT DROPPING INTO THE SINGLE DIGITS ABOVE
AND BELOW ZERO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 205 PM CST FRI DEC 13 2013
SUNDAY LOOKS DRY AT THIS TIME BUT CLOUDS WILL BE THICKENING ONCE
AGAIN IN ADVANCE OF THE NEXT MID-LEVEL SHORTWAVE TO IMPACT THE AREA.
FOR SUNDAY NIGHT INTO MONDAY...WARM AIR ADVECTION WING OF THIS WAVE
MOVES IN WITH A GOOD CHANCE FOR LIGHT SNOW TO OVERSPREAD THE AREA.
WILL HAVE TO WATCH CLOSELY AS MODEL BUFKIT SOUNDINGS HINT AT THE
POTENTIAL FOR SOME LOSS OF ICE IN THE COLUMN. THIS COULD LEAD TO
SOME FREEZING DRIZZLE ISSUES. KEPT PRECIPITATION AS ALL SNOW FOR NOW
AFTER COORDINATION/COLLABORATION WITH OTHER OFFICES...BUT WILL
REMAIN LEARY AND KEEP A CLOSE EYE ON LATER MODEL RUNS FOR FREEZING
DRIZZLE POTENTIAL. OTHERWISE...SNOWFALL LOOKS TO BE VERY LIGHT WITH
LESS THAN AN INCH EXPECTED.
TUESDAY THROUGH WEDNESDAY LOOK TO BE DRY FOR NOW AS NORTHWEST FLOW
ALOFT PERSISTS ACROSS THE EASTERN HALF OF THE CONUS.
ECMWF/GFS COMING INTO BETTER AGREEMENT WITH THE LOW PRESSURE SYSTEM
AFFECTING THE AREA ON THURSDAY. APPEARS THERE WILL BE ENOUGH WARM
AIR DRAWN IN WITH THIS SYSTEM TO PRODUCE A RAIN/SNOW MIX FOR
PORTIONS OF THE AREA AS TEMPERATURES WARM INTO THE LOWER/MIDDLE 30S
ALONG AND SOUTH OF I-90. LOOK FOR THE PRECIPITATION TO SWITCH BACK
TO ALL SNOW AS COLD AIR SWEEPS IN BEHIND THE DEPARTING LOW THURSDAY
NIGHT.
THERE WILL BE A LINGERING CHANCE FOR LIGHT SNOW ON FRIDAY AS A
POTENT/COLD MID-LEVEL TROUGH MOVES TOWARD THE UPPER MISSISSIPPI
RIVER FROM THE NORTHERN PLAINS. OTHERWISE...MUCH COLDER TEMPERATURES
LOOK TO INVADE THE AREA WITH HIGHS DROPPING BACK INTO THE TEENS/20S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1123 PM CST FRI DEC 13 2013
THE BAND OF MVFR CLOUDS MOVED BACK OVER BOTH TAF SITES AS EXPECTED
THIS EVENING AND NOW LOOKS LIKE IT WILL REMAIN THROUGH THE PERIOD.
THE THREAT FOR SOME SNOW WILL COME FROM THE SHORT WAVE TROUGH
APPROACHING FROM THE WEST. LIGHT SNOW IS FALLING AHEAD OF THIS
WAVE FROM WESTERN MINNESOTA INTO WISCONSIN WEST OF THE TWIN
CITIES. AS THE WAVE CONTINUES TO MOVE EAST...LOOK FOR THE LIGHT
SNOW TO SLOWLY MOVE SOUTHEAST AND SPREAD OVER THE TAF SITES DURING
THE OVERNIGHT HOURS. CONDITIONS ARE QUITE VARIABLE WITH THE
SNOW...BUT ARE PRIMARILY MVFR WITH SOME LOCATIONS REPORTING IFR
CONDITIONS. THIS CORRESPONDS WELL TO THE 14.00Z NAM AND 14.03Z RAP
BUFKIT SOUNDINGS FOR BOTH SITES AND WILL SHOW PREVAILING MVFR
CONDITIONS IN THE LIGHT SNOW WITH A PERIOD OF IFR POSSIBLE LATE
TONIGHT INTO EARLY SATURDAY MORNING. ONCE THE FORCING FROM THE
MAIN WAVE MOVES PAST...THE NAM SUGGEST SOME WEAK FRONTOGENESIS
IN THE 1000-850 MB LAYER WILL LINGER OVER EASTERN MINNESOTA INTO
THE DAY AS THE NEXT NORTHERN STREAM SHORT WAVE TROUGH MOVES ACROSS
THE REGION. WILL THUS KEEP A MVFR VISIBILITY INTO THE AFTERNOON
BEFORE GOING TO FLURRIES AS THE FRONTOGENESIS WEAKENS BY MID
AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS ALBANY NY
821 AM EST SAT DEC 14 2013
.SYNOPSIS...
ARCTIC HIGH PRESSURE SITUATED ACROSS THE SAINT LAWRENCE VALLEY
HAS USHERED IN A VERY COLD AND DRY AIR MASS INTO THE REGION.
MEANWHILE A COMPLEX WINTER STORM IS TAKING SHAPE ACROSS THE
CENTER OF THE NATION AND WILL TRACK TOWARD NEW ENGLAND TONIGHT.
THIS WILL SPREAD AN ACCUMULATING SNOW ACROSS MOST OF THE REGION.
THIS STORM WILL DEPART BY SUNDAY AFTERNOON WITH SLOW IMPROVEMENTS
TO OUR WEATHER EXPECTED.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
INCREASED POPS ACROSS THE SOUTHERN PORTION OF THE FORECAST AREA.
LIGHT SNOW IS OCCURRING ACROSS THE SOUTHEASTERN CATSKILLS...MID
HUDSON VALLEY AND LITCHFIELD COUNTY. RADAR RETURNS LOOK WEAK HOWEVER
METARS SHOW VISIBILITIES UNDER 3 MILES AND SOME UNDER 1 MILE.
ALSO ADJUSTED POPS SOME AS THE DAY PROGRESSES BRINGING CHANCES FOR
SNOW NORTHWARD THROUGH DAY. LATEST 06Z GUIDANCE AND HOURLY
RUC/HRRR CONTINUE ALONG THE SAME FORECAST THOUGHTS WITH WAA
ISENTROPIC LIFT EVOLVING ALONG A TIGHTENING BAROCLINIC ZONE ALONG
AND JUST NORTH OF THE NY STATE LINE. QPF/S CONTINUE TO SHOW A
SLIGHT INCREASE FROM PREVIOUS RUNS SO WE MADE SLIGHT ADJUSTMENTS
TO THE SNOWFALL FORECAST TODAY.
H2O VAPOR LOOP REVEALS OUR MAIN INGREDIENT FOR OUR WINTER STORM
WAS MOVING INTO THE TENNESSEE VALLEY. A STRENGTHENING UPPER JET IS
UNDERWAY ACROSS THE SOUTHERN CONUS PER SATELLITE WIND ESTIMATES
AND HOURLY RUC ANALYSIS WITH ANOTHER UPPER JET SEGMENT ACROSS THE
UPPER GREAT LAKES REGION. THIS NORTHERN PORTION OF THE JET IS
EXPECTED TO REMAIN CYCLONIC IN NATURE WHICH SUGGESTS THIS UPPER
LOW MAY TRACK A LITTLE FURTHER WEST AND HANGING ONTO THE INITIAL
SURFACE LOW LONGER BEFORE THE TRANSFER OCCURS OFF THE MID ATLANTIC
COAST. BROAD ISENTROPIC LIFT IN ADVANCE OF THESE FEATURES WAS
UNDERWAY ACROSS THE NY/PA BORDER AS BAROCLINICITY WAS INCREASING
JUST NORTH OF THE ARCTIC BOUNDARY. PER EXPERIMENTAL REFLECTIVITY
FORECASTS FROM A VARIETY OF MESOSCALE MODELS...ALONG WITH THE DRY
AIR IN PLACE...IT MAY TAKE MOST OF THE MORNING TO SATURATE THE
LOWER LEVELS FOR SNOW TO REACH THE GROUND /VIRGA/ NORTH OF I90 AS
LOW LEVEL AGEOSTROPIC FLOW REMAINS IN PLACE /MAGNITUDE IS NOT THAT
STRONG BUT IS VERY PERSISTENT/. USED A BLENDED APPROACH FOR HIGH
TEMPERATURES TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
WINTER STORM WARNING IN EFFECT FOR THE ENTIRE REGION...
PREVIOUS DISCUSSIONS HAVE DONE AN EXCELLENT JOB WITH THE
METEOROLOGICAL PARAMETERS SETTING UP FOR THIS FIRST WIDESPREAD
SIGNIFICANT WINTER EVENT FOR THE REGION. 00Z GUIDANCE ALONG WITH THE
RECENT ARRIVAL OF THE 06Z NAM/GFS CONTINUE TO INCREASE QPF AMOUNTS
ALONG WITH ENHANCED FGEN BANDS SEEN IN THE H850-H700 LAYER PER
PREVIOUS CSTAR RESEARCH. THESE BANDS ARE PROGGED TO BE A LITTLE
FURTHER NORTH AND PER COORDINATION FROM WPC AND SURROUNDING
WFOS...WE WILL UPGRADE THE ADVISORY AREA AND EXTEND THE WARNING
ACROSS THE ENTIRE CWFA. IT WILL BE CLOSE PER THE DEFINITION OF 7"
IN 12HRS OR 9" IN 24HRS BUT WITH A HIGH IMPACT WIDESPREAD EVENT
THE WARNING WAS EXPANDED. AS WARM ADVECTION OCCURS IN THE THERMAL
PROFILES...SOME OF THE PRECIP ACROSS DUTCHESS AND LITCHFIELD
COUNTIES WILL MIX WITH SLEET AND FREEZING RAIN LATE TONIGHT. ICE
ACCUMULATIONS UP TO TWO TENTHS OF AN INCH ARE POSSIBLE BEFORE THE
WARM AIR AT THE SURFACE ARRIVES TO RESULT IN A CHANGEOVER TO
MAINLY RAIN/RAIN SHOWERS LATER SUNDAY MORNING. SO TEMPERATURES
WILL BE STEADY TO SLOWLY RISING OVERNIGHT AS WE WILL SHOW A NON-
DIURNAL TEMPERATURE TREND OVERNIGHT.
THE OTHER COMPLICATED FACTOR TO THIS WILL BE TRANSITIONING
SNOW TO LIQUID RATIOS AS WE SHOULD INITIALLY BE RATHER HIGH WITH
15:1 RATIO THEN GRADUALLY DROPPING TOWARD CLIMATOLOGY OF 12:1 FOR
MOST OF THE REGION AND EVENTUALLY TOWARD 10:1 TOWARD SUNRISE
SUNDAY. THE CROSS SECTIONS NOW REVEAL WE WILL INDEED SEE THE BEST
LIFT OCCUR IN THE BEST DENDRITIC SNOW GROWTH REGION WHICH ALONG
WITH FGEN BANDS TO ENHANCE SNOWFALL RATES. IN FACT...D-THETA/DZ
SUGGESTS THE SMALL POTENTIAL FOR CONVECTIVE ELEMENTS BETWEEN 06Z-
12Z SUNDAY AND AS THE SECONDARY LOW DEVELOPS OFF THE NJ
COAST...THE DUCT FUNCTION POINTS TOWARD THE POTENTIAL FOR A
GRAVITY WAVE/S/.
PRECIP SHADOW IS INDEED STILL PLAUSIBLE TOO AS LOW-MID LEVEL EAST-
SOUTHEAST WINDS INCREASE SUGGESTING PRECIP SHADOW DOWNWIND OF THE
BERKS-TACONICS AND THE GREENS INTO PORTIONS OF WASHINGTON COUNTY.
THIS STORM DEEPENS SUNDAY AS IT TRACKS THROUGH THE SOUTHERN
PORTIONS OF THE GULF OF MAINE WITH DEFORMATION SNOW AXIS ACROSS
PORTIONS OF THE DACKS. WIND GUSTS WILL LIKELY INCREASE TOO WHICH
WILL RESULT IN SOME BLOWING AND DRIFTING OF THE SNOW.
FURTHERMORE...WIND CHILLS WILL LIKELY DIP WELL BELOW ZERO ACROSS
THE DACKS AS WE MAY NEED HEADLINES FOR THIS IN FUTURE FORECASTS.
SNOW WILL TAPER OFF THROUGH THE DAYLIGHT HOURS SUNDAY WITH SOME
LAKE RESPONSE SUNDAY NIGHT INTO PORTIONS OF THE DACKS...WESTERN
MOHAWK VALLEY AND CATSKILLS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
BEHIND THE DEPARTING WINTER STORM...HIGH PRESSURE WILL MOVE OVER
THE REGION FOR MONDAY. WITH A COLD NW FLOW IN PLACE...MAX TEMPS
WILL BE BELOW NORMAL...WITH TEENS TO MID 20S ACROSS THE REGION.
VERY COLD TEMP WILL CONTINUE INTO MONDAY NIGHT WITH SINGLE DIGITS
OVER MUCH OF THE AREA. SOME BELOW ZERO READINGS WILL OCCUR ACROSS
THE ADIRONDACKS AND GREEN MOUNTAINS.
CLOUDS WILL BEGIN TO INCREASE LATE MONDAY NIGHT...WITH A SLIGHT CHC
FOR SOME SNOW SHOWERS...AS A CLIPPER SYSTEM BEGINS TO APPROACH FROM
THE GREAT LAKES. THIS WEAK SYSTEM WILL BE QUITE MOISTURE STARVED.
STILL...THERE IS A CHANCE FOR SOME LIGHT SNOW ACROSS THE REGION FOR
TUESDAY INTO TUESDAY NIGHT AS THIS SYSTEM TRACKS ACROSS THE AREA.
ANY QPF LOOKS RATHER LIGHT...AND SNOWFALL WILL ONLY BE AN INCH OR
TWO FOR MOST PLACES. MAX TEMPS WILL CONTINUE TO BE CHILLY ON TUESDAY
WITH 20S OVER MUCH OF THE AREA...AND TEENS TO LOW 20S FOR TUESDAY
NIGHT.
SOME LAKE EFFECT SNOW WILL OCCUR ACROSS THE WESTERN ADIRONDACKS AND
WESTERN MOHAWK VALLEY BEHIND THIS CLIPPER SYSTEM FOR WED INTO WED
NIGHT. OTHERWISE...IT LOOKS DRY OVER MUCH OF THE AREA. TEMPS ON WED
WILL BE A LITTLE WARMER THAN RECENT DAYS...WITH MID 20S TO MID 30S.
HOWEVER...A REINFORCING SHOT OF COLD AIR LOOKS TO ARRIVE ON WED
NIGHT...WITH TEENS FOR THE AREA...AND TEMPS BACK INTO THE 20S FOR
THURSDAY.
THIS COLD SHOT LOOKS TO BE SHORT LIVED...AS HIGH PRESSURE QUICKLY
PASSES OVER THE AREA...AND THE PATTERN BEGINS TO SHIFT SOMEWHAT.
WHILE IT WILL BE DRY FOR THURSDAY...THE OVERALL FLOW STARTS TO
BECOME MORE OUT OF THE SW BOTH AT THE LOW LEVELS AND ALOFT. THIS
WILL TRANSPORT MUCH WARMER AND MORE MOIST AIR INTO THE REGION FOR
THE LATE WEEK PERIOD. MAX TEMPS LOOK TO REACH INTO THE 40S FOR
VALLEY AREAS BY FRIDAY. ALTHOUGH IT/S STILL RATHER FAR OUT IN
TIME...AN APPROACHING SLOW MOVING FRONTAL BOUNDARY LOOKS TO BRING A
PERIOD OF PLAIN RAIN TO THE REGION FOR LATE IN THE WEEK AND INTO THE
WEEKEND ACROSS THE ENTIRE REGION...EVEN THE HIGHER TERRAIN
AREAS...WITH A RETURN TO ABOVE NORMAL TEMPS EXPECTED INTO THE
WEEKEND.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
A STORM SYSTEM WILL MOVE TOWARDS THE OHIO VALLEY TODAY AND REFORM
OFF THE JERSEY SHORE BY THIS EVENING. AS THIS STORM SYSTEM EVOLVES
AND MOVES TOWARDS THE AREA...LIGHT SNOW WILL CONTINUE TO SLOWLY
SPREAD NORTHWARD. SNOW HAS ALREADY BEGUN AT KPOU...AND SHOULD BEGIN
AT KPSF SOON...KALB BY ABOUT MID MORNING...AND KGFL BY LATE MORNING
OR SO. INITIALLY...THE DRY AIRMASS IN PLACE WILL ONLY ALLOW FOR
LIGHT SNOW AND MVFR CONDITIONS. AFTER ABOUT AN HOUR OR TWO...IFR
SNOW LOOKS FALL WITHIN PERIODS OF LIGHT SNOW. ALTHOUGH AT FIRST THE
SNOW MAY NOT BE STEADY AND FLYING CONDITIONS FLUCTUATE BETWEEN
IFR/MVFR...ALL SITES SHOULD BE SEEING PREDOMINATELY IFR SNOW BY
LATER THIS AFTN AS THE SNOW BEGINS TO BECOME MORE WIDESPREAD. WINDS
TODAY WILL BE N-NE AT AROUND 5 KTS.
AS THE STORM STRENGTHENS RAPIDLY OFF THE COAST...THE SNOW WILL PICK
UP IN INTENSITY BY LATE THIS EVENING AND INTO THE OVERNIGHT HOURS.
AT THIS POINT...LIFR CONDITIONS ARE POSSIBLE AS WELL...WHEN THE SNOW
WILL BE FALLING ITS HARDEST AND VV WILL BE QUITE LIMITED. VSBYS WILL
BE LESS THAN ONE MILE...AND PERHAPS AS LOW AS 1/4SM TO 1/2SM. THE
PRECIP WILL MIX WITH AND CHANGE TO SLEET/FREEZING RAIN AT KPOU AFTER
MIDNIGHT...BUT THE REMAINING SITES WILL STAY ALL SNOW. THE SNOW MAY
START TO DECREASE IN INTENSITY LATE TONIGHT FROM SOUTH TO NORTH AS
THE STORM BEGINS TO MOVE UP TOWARDS NEW ENGLAND...ALTHOUGH FLYING
CONDITIONS WILL REMAIN IFR THROUGH 12Z.
OUTLOOK...
SUN: HIGH OPERATIONAL IMPACT. SN.
SUN NIGHT-MON: LOW OPERATIONAL IMPACT. BREEZY.
MON NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
TUE-TUE NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
WED: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
NO HYDRO RELATED CONCERNS ARE EXPECTED THE NEXT 5 DAYS.
QPF FROM THIS UPCOMING EVENT WILL RANGE FROM ONE HALF INCH TO ONE
AND ONE QUARTER OF AN INCH WITH THOSE HIGHER VALUES ACROSS THE
TERRAIN INTO THE CATSKILLS...SOUTHERN GREENS AND PORTIONS OF THE
DACKS. MOST OF THIS WILL FALL IN THE FORM OF SNOW WITH THE
EXCEPTION ACROSS DUTCHESS AND LITCHFIELD COUNTIES WHERE A WINTRY
MIXTURE AND PERHAPS A PERIOD OF RAIN MAY RESULT LATE SATURDAY
NIGHT INTO SUNDAY MORNING. ANY LIQUID PRECIP SHOULD RESULT WITHIN
BANK RISES.
THEREAFTER...TEMPS WILL CONTINUE TO BE BELOW NORMAL AND ICE WILL
CONTINUE TO FORM AND THICKEN ON AREA RIVERS...STREAMS AND
PARTICULARLY LAKES THROUGH EARLY NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR CTZ001-013.
NY...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR NYZ032-033-
038>043-047>054-058>061-063>066-082>084.
MA...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR MAZ001-025.
VT...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR VTZ013>015.
&&
$$
SYNOPSIS...BGM
NEAR TERM...IAA/BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...FRUGIS
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
620 AM EST SAT DEC 14 2013
.SYNOPSIS...
ARCTIC HIGH PRESSURE SITUATED ACROSS THE SAINT LAWRENCE VALLEY
HAS USHERED IN A VERY COLD AND DRY AIR MASS INTO THE REGION.
MEANWHILE A COMPLEX WINTER STORM IS TAKING SHAPE ACROSS THE
CENTER OF THE NATION AND WILL TRACK TOWARD NEW ENGLAND TONIGHT.
THIS WILL SPREAD AN ACCUMULATING SNOW ACROSS MOST OF THE REGION.
THIS STORM WILL DEPART BY SUNDAY AFTERNOON WITH SLOW IMPROVEMENTS
TO OUR WEATHER EXPECTED.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 600 AM EST...LIGHT SNOW WAS ALREADY DEVELOPING ACROSS THE
CATSKILLS...SCHOHARIE VALLEY...IN THE IMMEDIATE CAPITAL
REGION...BERKSHIRES...MID HUDSON VALLEY. RADAR REPRESENTATION IS
LESS THAN IMPRESSIVE AS MOST OF THIS SNOW IS FALLING VERY LIGHTLY.
LATEST 06Z GUIDANCE AND HOURLY RUC/HRRR CONTINUE ALONG THE SAME
FORECAST THOUGHTS WITH WAA ISENTROPIC LIFT EVOLVING ALONG A
TIGHTENING BAROCLINIC ZONE ALONG AND JUST NORTH OF THE NY STATE
LINE. QPF/S CONTINUE TO SHOW A SLIGHT INCREASE FROM PREVIOUS RUNS
SO WE MADE SLIGHT ADJUSTMENTS TO THE SNOWFALL FORECAST TODAY.
PREV DISC...
H2O VAPOR LOOP REVEALS OUR MAIN INGREDIENT FOR OUR
WINTER STORM WAS TRACKING ACROSS NORTHERN ARKANSAS AND SOUTHERN
MISSOURI AND TRACKING NORTHEAST TOWARD THE OHIO VALLEY. A
STRENGTHENING UPPER JET IS UNDERWAY ACROSS THE SOUTHERN CONUS PER
SATELLITE WIND ESTIMATES AND HOURLY RUC ANALYSIS WITH ANOTHER
UPPER JET SEGMENT ACROSS THE UPPER GREAT LAKES REGION. THIS
NORTHERN PORTION OF THE JET IS EXPECTED TO REMAIN CYCLONIC IN
NATURE WHICH SUGGESTS THIS UPPER LOW MAY TRACK A LITTLE FURTHER
WEST AND HANGING ONTO THE INITIAL SURFACE LOW LONGER BEFORE THE
TRANSFER OCCURS OFF THE MID ATLANTIC COAST. BROAD ISENTROPIC LIFT
IN ADVANCE OF THESE FEATURES WAS UNDERWAY ACROSS THE NY/PA BORDER
AS BAROCLINICITY WAS INCREASING JUST NORTH OF THE ARCTIC BOUNDARY.
PER EXPERIMENTAL REFLECTIVITY FORECASTS FROM A VARIETY OF
MESOSCALE MODELS...ALONG WITH THE DRY AIR IN PLACE...IT MAY TAKE
MOST OF THE MORNING TO SATURATE THE LOWER LEVELS FOR SNOW TO REACH
THE GROUND /VIRGA/ NORTH OF I90 AS LOW LEVEL AGEOSTROPIC FLOW
REMAINS IN PLACE /MAGNITUDE IS NOT THAT STRONG BUT IS VERY
PERSISTENT/. THEREFORE...WE WILL SLOW DOWN THE ONSET OF PRECIP IN
THE GRIDS FROM SOUTH TO NORTH TODAY. AS FOR HIGH
TEMPERATURES...BLENDED APPROACH OF THE MOS GUIDANCE WAS UTILIZED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
...WINTER STORM WARNING IN EFFECT FOR THE ENTIRE REGION...
PREVIOUS DISCUSSIONS HAVE DONE AN EXCELLENT JOB WITH THE
METEOROLOGICAL PARAMETERS SETTING UP FOR THIS FIRST WIDESPREAD
SIGNIFICANT WINTER EVENT FOR THE REGION. 00Z GUIDANCE ALONG WITH THE
RECENT ARRIVAL OF THE 06Z NAM/GFS CONTINUE TO INCREASE QPF AMOUNTS
ALONG WITH ENHANCED FGEN BANDS SEEN IN THE H850-H700 LAYER PER
PREVIOUS CSTAR RESEARCH. THESE BANDS ARE PROGGED TO BE A LITTLE
FURTHER NORTH AND PER COORDINATION FROM WPC AND SURROUNDING
WFOS...WE WILL UPGRADE THE ADVISORY AREA AND EXTEND THE WARNING
ACROSS THE ENTIRE CWFA. IT WILL BE CLOSE PER THE DEFINITION OF 7"
IN 12HRS OR 9" IN 24HRS BUT WITH A HIGH IMPACT WIDESPREAD EVENT
THE WARNING WAS EXPANDED. AS WARM ADVECTION OCCURS IN THE THERMAL
PROFILES...SOME OF THE PRECIP ACROSS DUTCHESS AND LITCHFIELD
COUNTIES WILL MIX WITH SLEET AND FREEZING RAIN LATE TONIGHT. ICE
ACCUMULATIONS UP TO TWO TENTHS OF AN INCH ARE POSSIBLE BEFORE THE
WARM AIR AT THE SURFACE ARRIVES TO RESULT IN A CHANGEOVER TO
MAINLY RAIN/RAIN SHOWERS LATER SUNDAY MORNING. SO TEMPERATURES
WILL BE STEADY TO SLOWLY RISING OVERNIGHT AS WE WILL SHOW A NON-
DIURNAL TEMPERATURE TREND OVERNIGHT.
THE OTHER COMPLICATED FACTOR TO THIS WILL BE TRANSITIONING
SNOW TO LIQUID RATIOS AS WE SHOULD INITIALLY BE RATHER HIGH WITH
15:1 RATIO THEN GRADUALLY DROPPING TOWARD CLIMATOLOGY OF 12:1 FOR
MOST OF THE REGION AND EVENTUALLY TOWARD 10:1 TOWARD SUNRISE
SUNDAY. THE CROSS SECTIONS NOW REVEAL WE WILL INDEED SEE THE BEST
LIFT OCCUR IN THE BEST DENDRITIC SNOW GROWTH REGION WHICH ALONG
WITH FGEN BANDS TO ENHANCE SNOWFALL RATES. IN FACT...D-THETA/DZ
SUGGESTS THE SMALL POTENTIAL FOR CONVECTIVE ELEMENTS BETWEEN 06Z-
12Z SUNDAY AND AS THE SECONDARY LOW DEVELOPS OFF THE NJ
COAST...THE DUCT FUNCTION POINTS TOWARD THE POTENTIAL FOR A
GRAVITY WAVE/S/.
PRECIP SHADOW IS INDEED STILL PLAUSIBLE TOO AS LOW-MID LEVEL EAST-
SOUTHEAST WINDS INCREASE SUGGESTING PRECIP SHADOW DOWNWIND OF THE
BERKS-TACONICS AND THE GREENS INTO PORTIONS OF WASHINGTON COUNTY.
THIS STORM DEEPENS SUNDAY AS IT TRACKS THROUGH THE SOUTHERN
PORTIONS OF THE GULF OF MAINE WITH DEFORMATION SNOW AXIS ACROSS
PORTIONS OF THE DACKS. WIND GUSTS WILL LIKELY INCREASE TOO WHICH
WILL RESULT IN SOME BLOWING AND DRIFTING OF THE SNOW.
FURTHERMORE...WIND CHILLS WILL LIKELY DIP WELL BELOW ZERO ACROSS
THE DACKS AS WE MAY NEED HEADLINES FOR THIS IN FUTURE FORECASTS.
SNOW WILL TAPER OFF THROUGH THE DAYLIGHT HOURS SUNDAY WITH SOME
LAKE RESPONSE SUNDAY NIGHT INTO PORTIONS OF THE DACKS...WESTERN
MOHAWK VALLEY AND CATSKILLS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
BEHIND THE DEPARTING WINTER STORM...HIGH PRESSURE WILL MOVE OVER
THE REGION FOR MONDAY. WITH A COLD NW FLOW IN PLACE...MAX TEMPS
WILL BE BELOW NORMAL...WITH TEENS TO MID 20S ACROSS THE REGION.
VERY COLD TEMP WILL CONTINUE INTO MONDAY NIGHT WITH SINGLE DIGITS
OVER MUCH OF THE AREA. SOME BELOW ZERO READINGS WILL OCCUR ACROSS
THE ADIRONDACKS AND GREEN MOUNTAINS.
CLOUDS WILL BEGIN TO INCREASE LATE MONDAY NIGHT...WITH A SLIGHT CHC
FOR SOME SNOW SHOWERS...AS A CLIPPER SYSTEM BEGINS TO APPROACH FROM
THE GREAT LAKES. THIS WEAK SYSTEM WILL BE QUITE MOISTURE STARVED.
STILL...THERE IS A CHANCE FOR SOME LIGHT SNOW ACROSS THE REGION FOR
TUESDAY INTO TUESDAY NIGHT AS THIS SYSTEM TRACKS ACROSS THE AREA.
ANY QPF LOOKS RATHER LIGHT...AND SNOWFALL WILL ONLY BE AN INCH OR
TWO FOR MOST PLACES. MAX TEMPS WILL CONTINUE TO BE CHILLY ON TUESDAY
WITH 20S OVER MUCH OF THE AREA...AND TEENS TO LOW 20S FOR TUESDAY
NIGHT.
SOME LAKE EFFECT SNOW WILL OCCUR ACROSS THE WESTERN ADIRONDACKS AND
WESTERN MOHAWK VALLEY BEHIND THIS CLIPPER SYSTEM FOR WED INTO WED
NIGHT. OTHERWISE...IT LOOKS DRY OVER MUCH OF THE AREA. TEMPS ON WED
WILL BE A LITTLE WARMER THAN RECENT DAYS...WITH MID 20S TO MID 30S.
HOWEVER...A REINFORCING SHOT OF COLD AIR LOOKS TO ARRIVE ON WED
NIGHT...WITH TEENS FOR THE AREA...AND TEMPS BACK INTO THE 20S FOR
THURSDAY.
THIS COLD SHOT LOOKS TO BE SHORT LIVED...AS HIGH PRESSURE QUICKLY
PASSES OVER THE AREA...AND THE PATTERN BEGINS TO SHIFT SOMEWHAT.
WHILE IT WILL BE DRY FOR THURSDAY...THE OVERALL FLOW STARTS TO
BECOME MORE OUT OF THE SW BOTH AT THE LOW LEVELS AND ALOFT. THIS
WILL TRANSPORT MUCH WARMER AND MORE MOIST AIR INTO THE REGION FOR
THE LATE WEEK PERIOD. MAX TEMPS LOOK TO REACH INTO THE 40S FOR
VALLEY AREAS BY FRIDAY. ALTHOUGH IT/S STILL RATHER FAR OUT IN
TIME...AN APPROACHING SLOW MOVING FRONTAL BOUNDARY LOOKS TO BRING A
PERIOD OF PLAIN RAIN TO THE REGION FOR LATE IN THE WEEK AND INTO THE
WEEKEND ACROSS THE ENTIRE REGION...EVEN THE HIGHER TERRAIN
AREAS...WITH A RETURN TO ABOVE NORMAL TEMPS EXPECTED INTO THE
WEEKEND.
&&
.AVIATION /11Z SATURDAY THROUGH WEDNESDAY/...
A STORM SYSTEM WILL MOVE TOWARDS THE OHIO VALLEY TODAY AND REFORM
OFF THE JERSEY SHORE BY THIS EVENING. AS THIS STORM SYSTEM EVOLVES
AND MOVES TOWARDS THE AREA...LIGHT SNOW WILL CONTINUE TO SLOWLY
SPREAD NORTHWARD. SNOW HAS ALREADY BEGUN AT KPOU...AND SHOULD BEGIN
AT KPSF SOON...KALB BY ABOUT MID MORNING...AND KGFL BY LATE MORNING
OR SO. INITIALLY...THE DRY AIRMASS IN PLACE WILL ONLY ALLOW FOR
LIGHT SNOW AND MVFR CONDITIONS. AFTER ABOUT AN HOUR OR TWO...IFR
SNOW LOOKS FALL WITHIN PERIODS OF LIGHT SNOW. ALTHOUGH AT FIRST THE
SNOW MAY NOT BE STEADY AND FLYING CONDITIONS FLUCTUATE BETWEEN
IFR/MVFR...ALL SITES SHOULD BE SEEING PREDOMINATELY IFR SNOW BY
LATER THIS AFTN AS THE SNOW BEGINS TO BECOME MORE WIDESPREAD. WINDS
TODAY WILL BE N-NE AT AROUND 5 KTS.
AS THE STORM STRENGTHENS RAPIDLY OFF THE COAST...THE SNOW WILL PICK
UP IN INTENSITY BY LATE THIS EVENING AND INTO THE OVERNIGHT HOURS.
AT THIS POINT...LIFR CONDITIONS ARE POSSIBLE AS WELL...WHEN THE SNOW
WILL BE FALLING ITS HARDEST AND VV WILL BE QUITE LIMITED. VSBYS WILL
BE LESS THAN ONE MILE...AND PERHAPS AS LOW AS 1/4SM TO 1/2SM. THE
PRECIP WILL MIX WITH AND CHANGE TO SLEET/FREEZING RAIN AT KPOU AFTER
MIDNIGHT...BUT THE REMAINING SITES WILL STAY ALL SNOW. THE SNOW MAY
START TO DECREASE IN INTENSITY LATE TONIGHT FROM SOUTH TO NORTH AS
THE STORM BEGINS TO MOVE UP TOWARDS NEW ENGLAND...ALTHOUGH FLYING
CONDITIONS WILL REMAIN IFR THROUGH 12Z.
OUTLOOK...
SUNDAY: HIGH OPERATIONAL IMPACT. SN.
SUNDAY NIGHT-MONDAY: LOW OPERATIONAL IMPACT.BREEZY NO SIG WX.
MONDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
TUESDAY-TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
NO HYDRO RELATED CONCERNS ARE EXPECTED THE NEXT 5 DAYS.
QPF FROM THIS UPCOMING EVENT WILL RANGE FROM ONE HALF INCH TO ONE
AND ONE QUARTER OF AN INCH WITH THOSE HIGHER VALUES ACROSS THE
TERRAIN INTO THE CATSKILLS...SOUTHERN GREENS AND PORTIONS OF THE
DACKS. MOST OF THIS WILL FALL IN THE FORM OF SNOW WITH THE
EXCEPTION ACROSS DUTCHESS AND LITCHFIELD COUNTIES WHERE A WINTRY
MIXTURE AND PERHAPS A PERIOD OF RAIN MAY RESULT LATE SATURDAY
NIGHT INTO SUNDAY MORNING. ANY LIQUID PRECIP SHOULD RESULT WITHIN
BANK RISES.
THEREAFTER...TEMPS WILL CONTINUE TO BE BELOW NORMAL AND ICE WILL
CONTINUE TO FORM AND THICKEN ON AREA RIVERS...STREAMS AND
PARTICULARLY LAKES THROUGH EARLY NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR CTZ001-013.
NY...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR NYZ032-033-
038>043-047>054-058>061-063>066-082>084.
MA...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR MAZ001-025.
VT...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR VTZ013>015.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...FRUGIS
HYDROLOGY...BGM
FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION...CORRECTED
NWS TAMPA BAY RUSKIN FL
500 AM EST SAT DEC 14 2013
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A UPPER LEVEL PATTERN IN
THE PROCESS OF TRANSITIONING FROM A GENERALLY ZONAL PATTERN OVER THE
EASTERN CONUS TO A PATTERN DOMINATED BY LONGWAVE TROUGHING. THE
LEADING IMPULSES IN THIS TRANSITION IS A STRONG SHORTWAVE EJECTING
EASTWARD FROM THE MID/LOWER MS VALLEY EARLY THIS MORNING TOWARD THE
TN VALLEY AND CAROLINAS. A SECONDARY SHORTWAVE AND IMPULSE IS
FOLLOWING CLOSE BEHIND OVER THE SOUTHERN PLAINS. THIS FIRST
SHORTWAVE WILL PASS WELL TO OUR NORTH DURING THE LATER MORNING
HOURS...AND THEN THE SECOND IMPULSE WILL MAKE A CLOSER PASS ALONG
THE NORTHERN GULF COAST TONIGHT AND SUNDAY. WV IMAGERY SHOWS LOTS OF
UPPER LEVEL MOISTURE STREAMING EASTWARD AHEAD OF THESE SYSTEMS
ACROSS THE GULF OF MEXICO AND FLORIDA PENINSULA. WV IMAGERY ALSO
SHOWS STRONG SUBSIDENCE/DRYING IN THE WAKE OF THIS LEAD
IMPULSE...HOWEVER THIS SUBSIDENCE WILL BYPASS WELL TO OUR NORTH AND
WE WILL NEED TO WAIT UNTIL THE WAKE OF THE SECONDARY SHORTWAVE LATER
SUNDAY AND SUNDAY NIGHT TO FINALLY CLEAR OUR SKIES ONCE AGAIN.
AT THE SURFACE...1028MB HIGH PRESSURE IS LETTING UP ITS INFLUENCE ON
THE FL PENINSULA THIS MORNING AS IT SLIDES EASTWARD INTO THE WESTERN
ATLANTIC IN RESPONSE TO A WAVE OF LOW PRESSURE MOVING EASTWARD FROM
THE LOWER MS VALLEY. A COLD FRONT CURRENTLY EXTENDS SOUTHWARD FROM
THIS FEATURE INTO THE WESTERN GULF OF MEXICO AND WILL BE MOVING
EASTWARD ACROSS THE GULF THROUGH THE DAY. SEEING A MUCH WARMER EARLY
MORNING THAN 24 HOURS AGO WITH MOST LOCATIONS HOLDING IN THE 50S AND
60S AS EAST AND SOUTHEASTERLY LOW LEVEL FLOW CONTINUES TO ADVECT
ATLANTIC MOISTURE ACROSS THE REGION.
&&
.SHORT TERM (TODAY THROUGH MONDAY)...
TODAY...FORECAST PHILOSOPHY HAS NOT CHANGED MUCH IN TERMS OF THE
SENSIBLE WEATHER AND TIMING OF THE FRONT AND FORCING MECHANISM
THROUGH THE NEXT 24 HOURS. AS THE LEAD SHORTWAVE PIVOTS
NORTHEASTWARD THROUGH THE DAY IT WILL DRAW THE SURFACE LOW
REFLECTION TO THE NORTHEAST AS WELL. THIS SURFACE FEATURE SHOULD
REACH THE EASTERN CAROLINAS AROUND SUNDOWN THIS EVENING WITH THE
COLD FRONT TRAILING BACK THROUGH GA TO THE FL PANHANDLE AND
NORTH-CENTRAL GULF. INITIAL "BATCH" OF DEEP LAYER QG-FORCING MISSES
THE REGION TO THE NORTH...AND THE SECOND ROUND OF FORCING AHEAD OF
THE SECOND SHORTWAVE DOES NOT BEGIN TO ARRIVE OVER OUR NORTHERN
ZONES UNTIL LATE TODAY AND THIS EVENING. THIS SYNOPTIC FORCING IS
ALSO NOT COMPLIMENTED BY ANY DECENT RRQ JET DYNAMICS UNTIL THIS
EVENING AND OVERNIGHT. WITH THE LOW LEVEL FOCUS OF THE FRONT MAINLY
TO OUR WEST ALL DAY AND THE LATE ARRIVAL OF THE UPPER FORCING...
STILL EXPECT MUCH OF THE FORECAST AREA TO SEE A GENERALLY DRY DAY.
DO BRING SCATTERED SHOWERS INTO THE NORTHERN NATURE COAST ZONES
AFTER 1-2PM...BUT DO NOT RAISE RAIN CHANCES TO LIKELY UNTIL AFTER
4-5PM. RAIN CHANCES WILL QUICKLY DECREASE SOUTHWARD TO THE I-4
CORRIDOR DURING THE LATER AFTERNOON HOURS...AND JUST HAVE ISOLATED
SHOWERS IN THE FORECAST FOR THE EARLY EVENING AROUND TAMPA BAY. FAR
REMOVED FROM THE FORCING LATER TODAY...AREAS SOUTH OF TAMPA BAY SHOW
A 10% POP OR LESS. IT WILL BE VERY WARM DECEMBER DAY WITHIN THE
THERMAL RIDGE AHEAD OF THE FRONT. THIS THERMAL RIDGE COMBINED WITH
DECENT DIURNAL MIXING WILL ALLOW MANY SPOTS TO REACH THE LOWER
80S...AND EVEN SOME MIDDLE 80S FOR THE SOUTHERN ZONES. BIGGER
QUESTION ON TEMPS WILL BE NORTH OF TAMPA BAY WHERE CLOUDS WILL
THICKEN/LOWER SOONER.
TONIGHT...SECONDARY SHORTWAVE QUICKLY HELPS TO EVOLVE/DEEPEN THE
LONGWAVE TROUGH OVER THE EASTERN CONUS TONIGHT...AND THE APPROACH OF
THIS ENERGY TO THE ATLANTIC COAST IS PROGGED TO RESULT IN RAPID
CYCLOGENESIS ALONG THE MID-ATLANTIC/NEW ENGLAND BAROCLINIC ZONE.
GFS/ECMWF STILL BOTH SHOW A DECENT SWATH OF QG-FORCING OVERSPREADING
THE NORTHERN HALF OF THE PENINSULA THIS EVENING AND OVERNIGHT...BUT
WITH TIME THE MAIN ENERGY WILL BEGIN TO TRANSLATE NORTHWARD TOWARD
THE DEEPENING SYSTEM OFF THE MID-ATLANTIC COAST. THE COLD FRONT IS
NOT THE FASTEST OF MOVING FEATURES AND TAKES MOST OF THE OVERNIGHT
TO REACH LEVY COUNTY AND THE NORTHERN MARINE ZONES. WITH THE MAIN
LOW LEVEL AND UPPER FORCING OVER THE NORTHERN PENINSULA...WILL SHOW
A FAIRLY TIGHT POP GRADIENT FROM CHANCE 40-55% POPS ALONG THE I-4
CORRIDOR TO CATEGORICAL 80-90% POPS UP TOWARD CITRUS/LEVY COUNTY.
FURTHER SOUTH FROM I-4...RAIN CHANCES DIMINISH QUICKLY AND LOOKING
FOR A MAINLY DRY OVERNIGHT FOR PLACES LIKE PUNTA GORDA AND FORT
MYERS OVER INTO HIGHLANDS COUNTY. 35-40KT LOW LEVEL JET MAY RESULT
IN A FEW STRONGER WIND GUSTS FOR LEVY COUNTY ASSOCIATED WITH ANY
STORMS...BUT THE OVERALL THREAT FOR SEVERE WEATHER APPEARS MARGINAL.
DEEP SOUTHWEST FLOW AHEAD OF THE FRONT WILL KEEP IT A WARM DECEMBER
NIGHT WITH LOW TEMPS FAILING TO FALL OUT OF THE MIDDLE AND UPPER
60S.
SUNDAY/SUNDAY NIGHT...
COLD FRONT BECOMES INCREASINGLY STRETCHED AS THE LOW NEAR NEW
ENGLAND DEEPENS AND QUICKLY MOVES NORTHEAST THROUGH THE DAY. THIS IS
A COMMON OCCURRENCE FOR US DURING THE COLD SEASON AND GENERALLY
MEANS THE CONVECTION AHEAD OF THE FRONT BECOMES LESS ORGANIZED WITH
TIME AS THE LOW LEVEL FOCUS DIMINISHES. THIS WILL HAPPEN HERE...BUT
WITH AT LEAST SOME WEAK LINGERING DEEP LAYER FORCING FOR
ASCENT...FEEL KEEPING CHANCE POPS IN THE FORECAST FOR ALL ZONES IN
THE MORNING IS APPROPRIATE...BUT WILL REMOVE THUNDER MENTION. AS THE
FRONT SLIPS SOUTH OF I-4 DURING THE AFTERNOON WILL REMOVE POPS FOR
THE TAMPA BAY AND NATURE COAST ZONES...AND THEN REMOVE ALL RAIN
CHANCES FURTHER SOUTH BY SUNDOWN SUNDAY EVENING. SKIES WILL ALSO
CLEAR FROM NORTH TO SOUTH DURING THE SECOND HALF OF SUNDAY AND
SUNDAY NIGHT. A COLDER AND MUCH DRIER AIRMASS WILL ARRIVE SUNDAY
NIGHT IN THE WAKE OF THE FRONT. IN GENERAL MOS GUIDANCE IS TOO COLD
ON THESE ADVECTION NIGHTS DIRECTLY BEHIND A FRONT...AND HAVE RAISED
A MAV/MET BLEND BY SEVERAL DEGREES FOR THE CURRENT LOW TEMPERATURE
FORECAST. AFTER THE ADJUSTMENT WE ARE LEFT WITH UPPER 30S AROUND
CHIEFLAND...RANGING DOWN TO AROUND 50 FOR I-4...AND MIDDLE/UPPER 50S
FOR FORT MYERS.
MONDAY...THE FIRST DAY OF THE NEW WORK WEEK LOOKS TO BE A
PLEASANT...SUNNY AND SEASONABLY COOL DAY AS HIGH PRESSURE BUILDS
EAST ALONG THE NORTHERN GULF COAST AND SUBSIDENCE EXPANDS OVERHEAD.
ENJOY YOUR SATURDAY!
&&
.LONG TERM (MONDAY NIGHT THROUGH NEXT FRIDAY)...
COOLER AND DRIER HIGH PRESSURE FROM THE NORTHERN GULF REGION WILL BE
IN PLACE ACROSS THE AREA KEEPING A GENERALLY N/NE FLOW IN PLACE
THROUGH TUESDAY. THE HIGH PRESSURE CENTER THEN SLOWLY SHIFTS TO THE
NORTHEAST ACROSS THE SOUTHEASTERN STATES TUESDAY NIGHT THROUGH
THURSDAY SHIFTING WINDS TO THE NE AND EAST ALLOWING MOISTURE AND
TEMPERATURES TO MODERATE. THE HIGH CENTER SHIFTS OFFSHORE OVER THE
WEST ATLANTIC FOR THURSDAY NIGHT AND FRIDAY WITH WINDS SHIFTING TO
THE E/SE AND A SLIGHT CHANCE OF RAIN POSSIBLE WITH THE INCREASED
MOISTURE FOR FRIDAY AFTERNOON MAINLY ACROSS THE SOUTH. TEMPERATURES
WILL BEGIN BELOW NORMAL FOR MONDAY NIGHT...THEN NEAR NORMAL TUESDAY
THROUGH WEDNESDAY NIGHT...AND RISING ABOVE NORMAL THROUGH THE REST
OF THE PERIOD.
&&
.AVIATION...
MVFR CEILINGS ARE EXPECTED TO DEVELOP ACROSS THE AREA OVER THE NEXT
COUPLE OF HOURS BEFORE SUNRISE WITH SOME PATCHY FOG ALSO POSSIBLE
MAINLY AT THE KLAL AND KPGD TERMINALS. CONDITIONS SHOULD LIFT BY 15Z
WITH VFR THEN EXPECTED THROUGH THE REST OF THE PERIOD. A COUPLE OF
SHOWERS WILL BE POSSIBLE IN THE LATE AFTERNOON/EARLY EVENING ACROSS
THE NORTHERN TERMINALS...BUT CHANCES ARE CURRENTLY TOO LOW TO
INCLUDE IN THE TAF.
&&
.MARINE...
HIGH PRESSURE MOVES AWAY FROM THE REGION AS A COLD FRONT APPROACHES
FROM THE WEST LATER TODAY AND TONIGHT. CAUTIONARY LEVEL WINDS AWAY
FROM SHORE TODAY WILL SHIFT TO MARINE ZONES MAINLY NORTH OF TARPON
SPRINGS BY TONIGHT. THE COLD FRONT WILL PUSH NORTHWEST TO SOUTHEAST
ACROSS THE EASTERN GULF ON SUNDAY WITH A WINDS SHIFT FROM SOUTHWEST
TO NORTHWEST AND NORTH. A PERIOD OF CAUTIONARY TO LOW END ADVISORY
LEVEL WINDS FROM THE NORTH IS ANTICIPATED FOR LATER SUNDAY INTO
MONDAY. SHOWERS AND THUNDERSTORMS WILL BECOME NUMEROUS TO WIDESPREAD
IN NATURE LATER TODAY INTO TONIGHT FROM TARPON SPRINGS NORTHWARD AND
SCATTERED IN NATURE FURTHER SOUTH. SHOWERS WILL CLEAR FROM NORTH TO
SOUTH ON SUNDAY WITH THE FRONTAL PASSAGE.
&&
.FIRE WEATHER...
ABUNDANT LOW LEVEL MOISTURE AHEAD OF AN APPROACHING COLD FRONT WILL
KEEP RELATIVE HUMIDITY VALUES WELL ABOVE CRITICAL LEVELS TODAY
DESPITE UNSEASONABLY WARM TEMPERATURES. WINDS WILL BE SOMEWHAT GUSTY
FROM THE SOUTHEAST AND SOUTH THROUGH THE DAY WITH MODERATE TO HIGH
DISPERSION INDICES. A COLD FRONT WILL SHIFT SOUTH ACROSS THE REGION
WITH A WIND SHIFT TO THE NORTHWEST IN ITS WAKE ON SUNDAY. THE MAIN
ARRIVAL OF DRIER AIR IS NOT EXPECTED UNTIL SUNDAY NIGHT AND MONDAY
AND NO FIRE WEATHER CONCERNS ARE ANTICIPATED FOR SUNDAY. WITH THE
DRIER AIR IN PLACE BY MONDAY...RELATIVE HUMIDITY VALUES ARE
CURRENTLY ANTICIPATED TO BRIEFLY REACH CRITICAL LEVELS FOR MUCH OF
THE AREA.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 81 69 76 52 / 20 60 50 0
FMY 83 69 82 59 / 10 20 40 10
GIF 82 67 77 50 / 20 40 50 0
SRQ 80 69 76 55 / 10 40 50 0
BKV 82 67 74 46 / 30 60 50 0
SPG 80 69 74 56 / 20 50 50 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WEATHER...MROCZKA
LONG TERM/AVIATION...COLSON
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
930 AM EST SAT DEC 14 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 356 AM EST SAT DEC 14 2013
ACCUMULATING SNOW WILL CONTINUE ACROSS MUCH OF THE FORECAST AREA
TODAY AS LOW PRESSURE TRACKS THROUGH THE OHIO VALLEY. ARCTIC AIR
WILL RETURN TONIGHT AS THE STORM MOVES AWAY TO THE EAST...WITH
CHILLY TEMPERATURES INTO THE EARLY PART OF THE WEEK. HIGH PRESSURE
WILL BRING DRY WEATHER AND A WARMING TREND THROUGH MIDWEEK.
UNSETTLED WEATHER RETURNS LATE THURSDAY AND FRIDAY AS LOW PRESSURE
TRACKS THROUGH THE REGION...WITH TEMPERATURES WARM ENOUGH FOR
PRECIPITATION TO FALL AS RAIN ACROSS CENTRAL INDIANA.
&&
.NEAR TERM /TODAY/...
ISSUED AT 356 AM EST SAT DEC 14 2013
COMPLEX WINTER STORM ONGOING ACROSS THE REGION EARLY THIS MORNING.
STEADIER SNOWS CONTINUE TO FALL OVER NORTHERN COUNTIES WITH A DRY
SLOT FURTHER SOUTH LIMITING PRECIP TO VERY LIGHT SNOW OR SHUTTING IT
OFF COMPLETELY ACROSS MUCH OF THE REST OF THE FORECAST AREA. BROADER
AREA OF HEAVIER PRECIPITATION QUICKLY EXPANDING NORTHEAST OUT OF THE
LOWER OHIO VALLEY. TEMPS WERE IN THE LOWER AND MIDDLE 30S AS OF 08Z.
DRY SLOT IS TAKING ITS TIME TO FILL IN...BUT EXPECT AREA OF HEAVIER
PRECIPITATION WILL EXPAND INTO THE FORECAST AREA OVER THE NEXT
SEVERAL HOURS WITH SNOWFALL COMMENCING ONCE AGAIN IN LOCATIONS WHERE
IT HAS STOPPED. RAP/NAM BOTH INDICATING A 50KT LOW LEVEL JET RIDING
UP THE MISSISSIPPI VALLEY AND CONTRIBUTING TO THE EXPANSION OF
PRECIP OVER THE LOWER OHIO VALLEY. THE LOW LEVEL JET WILL SHIFT EAST
ACROSS THE REGION AHEAD OF THE 850MB LOW THROUGH
MIDDAY...MAINTAINING A PLENTIFUL SURGE OF LOW LEVEL MOISTURE INTO
THE REGION. MAIN UPPER LEVEL WAVE LOCATED OVER SOUTHWEST MISSOURI
EARLY THIS MORNING WILL LIFT NORTHEAST ACROSS THE FORECAST AREA BY
EARLY AFTERNOON. SHORT RANGE MODEL GUIDANCE CONTINUING TO ADVERTISE
A DEFORMATION AXIS AND FRONTOGENETICAL FORCING WITHIN THE MID LEVELS
EXPANDING INTO THE FORECAST AREA PRIOR TO DAYBREAK AHEAD OF THE
UPPER WAVE.
ALL OF THESE FEATURES REMAIN SUPPORTIVE OF THE RESUMPTION OF
WIDESPREAD SNOW AND EXPECTATION FOR ADDITIONAL ACCUMULATIONS INTO
THE EARLY AFTERNOON...ESPECIALLY ACROSS THE NORTHERN HALF OF THE
FORECAST AREA. WITH THAT BEING SAID...TEMPERATURES WITHIN THE
BOUNDARY LAYER NEED TO BE MONITORED OVER THE NEXT SEVERAL HOURS AS
IMPACTS TO PRECIP TYPE OVER SOUTHERN COUNTIES AND SNOWFALL RATIOS IN
GENERAL ARE POSSIBLE. LAPS SOUNDINGS INDICATING A VERY SHALLOW LAYER
OF AIR NEAR THE SURFACE THAT SITS JUST ABOVE FREEZING OVER THE
SOUTHERN HALF OF THE FORECAST AREA WITH TEMPS AT 32-35F. WITH THE
LOW LEVEL JET TRANSPORTING SLIGHTLY WARMER BOUNDARY LAYER AIR NORTH
OVER THE NEXT FEW HOURS...EXPECTING SURFACE TEMPS TO MOVE LITTLE AND
MAY EVEN RISE A FEW DEGREES AFTER DAYBREAK. OVERALL...LOW LEVEL
THERMALS OVER THE NEXT SEVERAL HOURS REMAIN SUGGESTIVE OF SNOW AS
RATES INTENSIFY WITH THE EXPANSION OF THE PRECIP SHIELD. AS SLIGHTLY
WARMER AIR NOSES INTO SOUTHERN COUNTIES WITH THE LOW LEVEL JET AFTER
DAYBREAK HOWEVER...POTENTIAL FOR SOME LIGHT RAIN TO MIX IN WITH THE
SNOW. RAP AND NAM ARE THE MOST AGGRESSIVE WITH BRINGING THE 0C LINE
AT 850MB ACROSS THE SOUTHEASTERN HALF OF THE FORECAST AREA THROUGH
18Z...BOTH HINTING AT A TROWAL ROTATING INTO OUR SOUTHEAST AND
EASTERN COUNTIES. CONSIDERING RECENT TRENDS AND THE FACT THAT
SURFACE TEMPS ARE RUNNING A FEW DEGREES WARMER THAN PREVIOUSLY
THOUGHT...WILL BRING CHANCE FOR RAIN TO MIX IN WITH SNOW TO A
VINCENNES-BEDFORD-GREENSBURG LINE BY MID MORNING CONTINUING INTO
EARLY AFTERNOON.
CONSIDERING ABOVE THOUGHTS AND TAKING INTO ACCOUNT LIQUID TO
SNOWFALL RATIOS LIKELY REMAINING NEAR 10-1 FOR MUCH OF THE FORECAST
AREA FOR THE DURATION OF THE EVENT...HAVE TRIMMED TOTAL SNOWFALL
AMOUNTS A BIT OVER ALL BUT FAR NORTHERN SECTIONS. TOTAL SNOW ACCUMS
INCLUDING WHAT FELL SINCE FRIDAY EVENING STILL EXPECTED TO AROUND
6-7 INCHES OVER FAR NORTHERN COUNTIES...DIMINISHING TO 4-5 ALONG THE
I-70 CORRIDOR. FURTHER SOUTH...EXPECTING TOTALS GENERALLY AT 1-3
INCHES. THE NORTHWARD EXTENT OF THE ABOVE FREEZING AIR WITHIN THE
BOUNDARY LAYER AND THE POSSIBILITY OF ENHANCED FORCING IN THE
VICINITY OF A TROWAL COULD LEAD TO FURTHER ADJUSTMENTS IN THESE
AMOUNTS AND WILL CONTINUE TO MONITOR. THE WARNING AND ADVISORY WILL
CONTINUE IN THEIR CURRENT STATES THROUGH 23Z.
TEMPS...NEARLY STEADY TEMPS EXPECTED TODAY BUT IN GENERAL STILL FEEL
MOS IS TOO WARM WITH HIGHS. LEANED CLOSER TO CONSALL WITH TEMPS
RANGING FROM THE LOWER 30S NORTH TO MID 30S SOUTH.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 356 AM EST SAT DEC 14 2013
FORECAST CHALLENGES FOCUS ON MINOR SNOW CHANCES AND TEMPERATURES AS
COLDER AIR RETURNS FOR MUCH OF THE SHORT TERM.
ANY LINGERING LIGHT SNOW ON THE BACK SIDE OF THE DEPARTING SYSTEM
WILL END DURING THE EVENING...POSSIBLY AS A BRIEF PERIOD OF DRIZZLE
OR FREEZING DRIZZLE AS DRIER AIR DEEPENS ABOVE THE BOUNDARY LAYER.
LOW CLOUDS WILL PERSIST ALL NIGHT AS MOISTURE REMAINS TRAPPED
BENEATH A SHARP INVERSION.
THE PASSAGE OF TWO DEEP UPPER LOWS TO THE NORTH OF THE GREAT LAKES
WILL MAINTAIN BROAD TROUGHING ALOFT AND A GENERAL NORTHWEST FLOW
THROUGHOUT THE PERIOD. SEVERAL DISTURBANCES ALOFT WILL TRAVERSE THE
REGION MAINTAINING MOSTLY CLOUDY CONDITIONS AND BRINGING PERIODIC
LIGHT SNOW SHOWERS AND FLURRIES ACROSS MUCH OF THE FORECAST AREA.
FLURRIES ARE POSSIBLE WITHIN A BROAD CYCLONIC FLOW SUNDAY AND SUNDAY
NIGHT. STRONGER UPPER WAVE SET TO TRACK ACROSS THE LOWER GREAT LAKES
MONDAY AND WILL CARRY CHANCES FOR SNOW SHOWERS THROUGHOUT THE DAY.
SOUTHERLY FLOW WILL DEVELOP ON THE BACK SIDE OF A SURFACE HIGH
PRESSURE RIDGE BY MONDAY ALLOWING FOR WARM ADVECTION TO DEVELOP WITH
MODERATING TEMPS.
TEMPS...PREFER THE COLDER MAVMOS THROUGH MUCH OF THE PERIOD AS IT
APPEARS TO CAPTURE THE INFLUENCE FROM THE LEFTOVER SNOWPACK FROM
STORM TODAY BETTER. HIGHS WILL FALL BACK INTO THE LOWER/MIDDLE 20S
ON SUNDAY WITH STRONG COLD ADVECTION. THE SHIFT TO SOUTHERLY FLOW
MONDAY WILL ALLOW FOR A RECOVERY INTO THE 30S OVER SOUTHERN
COUNTIES. LOWS IN THE TEENS TONIGHT AND SUNDAY NIGHT WILL RECOVER
INTO THE 20S MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
ISSUED AT 357 AM EST SAT DEC 14 2013
THE EXTENDED PERIOD WILL START OUT WITH WEAK SHORTWAVES ROTATING
AROUND AN UPPER LOW OVER ONTARIO. THIS WILL RESULT IN LIGHT SNOW
SHOWERS OVER NORTHERN INDIANA. HOWEVER...CHOSE TO LEAVE PRECIP OUT
OF CENTRAL INDIANA ON TUESDAY SINCE BEST LIFT WILL BE NORTH OF
FORECAST AREA. DRY CONDITIONS WILL PREVAIL THROUGH MID-WEEK WITH
DECENT SUBSIDENCE ALOFT. HOWEVER...THE RIDGING OVER THE CENTRAL
U.S. WILL START TO BREAK DOWN BY THURSDAY AS A LOW PRESSURE SYSTEM
STRENGTHENS OVER THE WESTERN UNITED STATES. MEANWHILE...WARM AIR
WILL BE ADVECTED INTO CENTRAL INDIANA AHEAD OF A SURFACE
LOW...RESULTING IN ABOVE NORMAL TEMPERATURES. PRECIP ASSOCIATED
WITH THAT SURFACE LOW WILL INITIALLY FALL IN THE FORM OF RAIN ON
THURSDAY NIGHT AND FRIDAY...AND THEN TRANSITION TO A RAIN/SNOW MIX
AS COLDER AIR FILTERS IN BEHIND THE ASSOCIATED COLD FRONT.
&&
.AVIATION /DISCUSSION FOR THE 141500Z KIND TAF UPDATE/...
ISSUED AT 930 AM EST SAT DEC 14 2013
RADAR INDICATES HEAVIER PRECIPITATION MAY BE MOVING INTO THE KIND
AREA OVER THE NEXT HOUR OR SO. SURFACE REPORTS SUGGEST THE RAIN/SNOW
LINE IS GETTING CLOSE TO KIND...SO CONFIDENCE IN PRECIPITATION TYPE
FORECAST FOR THE NEXT SEVERAL HOURS IS LOW. APPEARS BASED ON DUAL
POL PRODUCTS THAT THE RAIN/SNOW LINE IS BEGINNING TO RETREAT AFTER
ADVANCING NORTH OVER THE PAST HOUR TO SO. FOR NOW...WILL KEEP ALL
SNOW IN THE FORECAST WITH POTENTIAL FOR PERIODS OF MODERATE SNOW
THROUGH THE EARLY AFTERNOON.
WILL BACK THE WIND FORECAST A BIT BASED ON CURRENT TRENDS. PREVIOUS
DISCUSSION FOLLOWS.
LIFR CONDITIONS CAN BE EXPECTED WELL INTO THIS AFTERNOON AS BANDS
OF SNOW CONTINUE TO PASS OVER TAF SITES. SNOW SHOWERS WILL WEAKEN
AFTER SAT 21Z AND THEN COME TO AN END AROUND SUN 00Z. MINIMAL
IMPROVEMENTS IN VISIBILITIES CAN BE EXPECTED BY THIS EVENING...BUT
DO NOT EXPECT CEILINGS TO IMPROVE TO MVFR CATEGORY UNTIL AFTER SUN
06Z. WINDS WILL BECOME NORTHWESTERLY THIS AFTERNOON AND STRENGTHEN
SLIGHTLY DURING THE EVENING HOURS WITH SUSTAINED SPEEDS OF
8 TO 12 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
INZ053>057-060>065-067>072.
WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR INZ021-
028>031-035>049-051-052.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...TDUD/JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
627 AM EST SAT DEC 14 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 356 AM EST SAT DEC 14 2013
ACCUMULATING SNOW WILL CONTINUE ACROSS MUCH OF THE FORECAST AREA
TODAY AS LOW PRESSURE TRACKS THROUGH THE OHIO VALLEY. ARCTIC AIR
WILL RETURN TONIGHT AS THE STORM MOVES AWAY TO THE EAST...WITH
CHILLY TEMPERATURES INTO THE EARLY PART OF THE WEEK. HIGH PRESSURE
WILL BRING DRY WEATHER AND A WARMING TREND THROUGH MIDWEEK.
UNSETTLED WEATHER RETURNS LATE THURSDAY AND FRIDAY AS LOW PRESSURE
TRACKS THROUGH THE REGION...WITH TEMPERATURES WARM ENOUGH FOR
PRECIPITATION TO FALL AS RAIN ACROSS CENTRAL INDIANA.
&&
.NEAR TERM /TODAY/...
ISSUED AT 356 AM EST SAT DEC 14 2013
COMPLEX WINTER STORM ONGOING ACROSS THE REGION EARLY THIS MORNING.
STEADIER SNOWS CONTINUE TO FALL OVER NORTHERN COUNTIES WITH A DRY
SLOT FURTHER SOUTH LIMITING PRECIP TO VERY LIGHT SNOW OR SHUTTING IT
OFF COMPLETELY ACROSS MUCH OF THE REST OF THE FORECAST AREA. BROADER
AREA OF HEAVIER PRECIPITATION QUICKLY EXPANDING NORTHEAST OUT OF THE
LOWER OHIO VALLEY. TEMPS WERE IN THE LOWER AND MIDDLE 30S AS OF 08Z.
DRY SLOT IS TAKING ITS TIME TO FILL IN...BUT EXPECT AREA OF HEAVIER
PRECIPITATION WILL EXPAND INTO THE FORECAST AREA OVER THE NEXT
SEVERAL HOURS WITH SNOWFALL COMMENCING ONCE AGAIN IN LOCATIONS WHERE
IT HAS STOPPED. RAP/NAM BOTH INDICATING A 50KT LOW LEVEL JET RIDING
UP THE MISSISSIPPI VALLEY AND CONTRIBUTING TO THE EXPANSION OF
PRECIP OVER THE LOWER OHIO VALLEY. THE LOW LEVEL JET WILL SHIFT EAST
ACROSS THE REGION AHEAD OF THE 850MB LOW THROUGH
MIDDAY...MAINTAINING A PLENTIFUL SURGE OF LOW LEVEL MOISTURE INTO
THE REGION. MAIN UPPER LEVEL WAVE LOCATED OVER SOUTHWEST MISSOURI
EARLY THIS MORNING WILL LIFT NORTHEAST ACROSS THE FORECAST AREA BY
EARLY AFTERNOON. SHORT RANGE MODEL GUIDANCE CONTINUING TO ADVERTISE
A DEFORMATION AXIS AND FRONTOGENETICAL FORCING WITHIN THE MID LEVELS
EXPANDING INTO THE FORECAST AREA PRIOR TO DAYBREAK AHEAD OF THE
UPPER WAVE.
ALL OF THESE FEATURES REMAIN SUPPORTIVE OF THE RESUMPTION OF
WIDESPREAD SNOW AND EXPECTATION FOR ADDITIONAL ACCUMULATIONS INTO
THE EARLY AFTERNOON...ESPECIALLY ACROSS THE NORTHERN HALF OF THE
FORECAST AREA. WITH THAT BEING SAID...TEMPERATURES WITHIN THE
BOUNDARY LAYER NEED TO BE MONITORED OVER THE NEXT SEVERAL HOURS AS
IMPACTS TO PRECIP TYPE OVER SOUTHERN COUNTIES AND SNOWFALL RATIOS IN
GENERAL ARE POSSIBLE. LAPS SOUNDINGS INDICATING A VERY SHALLOW LAYER
OF AIR NEAR THE SURFACE THAT SITS JUST ABOVE FREEZING OVER THE
SOUTHERN HALF OF THE FORECAST AREA WITH TEMPS AT 32-35F. WITH THE
LOW LEVEL JET TRANSPORTING SLIGHTLY WARMER BOUNDARY LAYER AIR NORTH
OVER THE NEXT FEW HOURS...EXPECTING SURFACE TEMPS TO MOVE LITTLE AND
MAY EVEN RISE A FEW DEGREES AFTER DAYBREAK. OVERALL...LOW LEVEL
THERMALS OVER THE NEXT SEVERAL HOURS REMAIN SUGGESTIVE OF SNOW AS
RATES INTENSIFY WITH THE EXPANSION OF THE PRECIP SHIELD. AS SLIGHTLY
WARMER AIR NOSES INTO SOUTHERN COUNTIES WITH THE LOW LEVEL JET AFTER
DAYBREAK HOWEVER...POTENTIAL FOR SOME LIGHT RAIN TO MIX IN WITH THE
SNOW. RAP AND NAM ARE THE MOST AGGRESSIVE WITH BRINGING THE 0C LINE
AT 850MB ACROSS THE SOUTHEASTERN HALF OF THE FORECAST AREA THROUGH
18Z...BOTH HINTING AT A TROWAL ROTATING INTO OUR SOUTHEAST AND
EASTERN COUNTIES. CONSIDERING RECENT TRENDS AND THE FACT THAT
SURFACE TEMPS ARE RUNNING A FEW DEGREES WARMER THAN PREVIOUSLY
THOUGHT...WILL BRING CHANCE FOR RAIN TO MIX IN WITH SNOW TO A
VINCENNES-BEDFORD-GREENSBURG LINE BY MID MORNING CONTINUING INTO
EARLY AFTERNOON.
CONSIDERING ABOVE THOUGHTS AND TAKING INTO ACCOUNT LIQUID TO
SNOWFALL RATIOS LIKELY REMAINING NEAR 10-1 FOR MUCH OF THE FORECAST
AREA FOR THE DURATION OF THE EVENT...HAVE TRIMMED TOTAL SNOWFALL
AMOUNTS A BIT OVER ALL BUT FAR NORTHERN SECTIONS. TOTAL SNOW ACCUMS
INCLUDING WHAT FELL SINCE FRIDAY EVENING STILL EXPECTED TO AROUND
6-7 INCHES OVER FAR NORTHERN COUNTIES...DIMINISHING TO 4-5 ALONG THE
I-70 CORRIDOR. FURTHER SOUTH...EXPECTING TOTALS GENERALLY AT 1-3
INCHES. THE NORTHWARD EXTENT OF THE ABOVE FREEZING AIR WITHIN THE
BOUNDARY LAYER AND THE POSSIBILITY OF ENHANCED FORCING IN THE
VICINITY OF A TROWAL COULD LEAD TO FURTHER ADJUSTMENTS IN THESE
AMOUNTS AND WILL CONTINUE TO MONITOR. THE WARNING AND ADVISORY WILL
CONTINUE IN THEIR CURRENT STATES THROUGH 23Z.
TEMPS...NEARLY STEADY TEMPS EXPECTED TODAY BUT IN GENERAL STILL FEEL
MOS IS TOO WARM WITH HIGHS. LEANED CLOSER TO CONSALL WITH TEMPS
RANGING FROM THE LOWER 30S NORTH TO MID 30S SOUTH.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 356 AM EST SAT DEC 14 2013
FORECAST CHALLENGES FOCUS ON MINOR SNOW CHANCES AND TEMPERATURES AS
COLDER AIR RETURNS FOR MUCH OF THE SHORT TERM.
ANY LINGERING LIGHT SNOW ON THE BACK SIDE OF THE DEPARTING SYSTEM
WILL END DURING THE EVENING...POSSIBLY AS A BRIEF PERIOD OF DRIZZLE
OR FREEZING DRIZZLE AS DRIER AIR DEEPENS ABOVE THE BOUNDARY LAYER.
LOW CLOUDS WILL PERSIST ALL NIGHT AS MOISTURE REMAINS TRAPPED
BENEATH A SHARP INVERSION.
THE PASSAGE OF TWO DEEP UPPER LOWS TO THE NORTH OF THE GREAT LAKES
WILL MAINTAIN BROAD TROUGHING ALOFT AND A GENERAL NORTHWEST FLOW
THROUGHOUT THE PERIOD. SEVERAL DISTURBANCES ALOFT WILL TRAVERSE THE
REGION MAINTAINING MOSTLY CLOUDY CONDITIONS AND BRINGING PERIODIC
LIGHT SNOW SHOWERS AND FLURRIES ACROSS MUCH OF THE FORECAST AREA.
FLURRIES ARE POSSIBLE WITHIN A BROAD CYCLONIC FLOW SUNDAY AND SUNDAY
NIGHT. STRONGER UPPER WAVE SET TO TRACK ACROSS THE LOWER GREAT LAKES
MONDAY AND WILL CARRY CHANCES FOR SNOW SHOWERS THROUGHOUT THE DAY.
SOUTHERLY FLOW WILL DEVELOP ON THE BACK SIDE OF A SURFACE HIGH
PRESSURE RIDGE BY MONDAY ALLOWING FOR WARM ADVECTION TO DEVELOP WITH
MODERATING TEMPS.
TEMPS...PREFER THE COLDER MAVMOS THROUGH MUCH OF THE PERIOD AS IT
APPEARS TO CAPTURE THE INFLUENCE FROM THE LEFTOVER SNOWPACK FROM
STORM TODAY BETTER. HIGHS WILL FALL BACK INTO THE LOWER/MIDDLE 20S
ON SUNDAY WITH STRONG COLD ADVECTION. THE SHIFT TO SOUTHERLY FLOW
MONDAY WILL ALLOW FOR A RECOVERY INTO THE 30S OVER SOUTHERN
COUNTIES. LOWS IN THE TEENS TONIGHT AND SUNDAY NIGHT WILL RECOVER
INTO THE 20S MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
ISSUED AT 357 AM EST SAT DEC 14 2013
THE EXTENDED PERIOD WILL START OUT WITH WEAK SHORTWAVES ROTATING
AROUND AN UPPER LOW OVER ONTARIO. THIS WILL RESULT IN LIGHT SNOW
SHOWERS OVER NORTHERN INDIANA. HOWEVER...CHOSE TO LEAVE PRECIP OUT
OF CENTRAL INDIANA ON TUESDAY SINCE BEST LIFT WILL BE NORTH OF
FORECAST AREA. DRY CONDITIONS WILL PREVAIL THROUGH MID-WEEK WITH
DECENT SUBSIDENCE ALOFT. HOWEVER...THE RIDGING OVER THE CENTRAL
U.S. WILL START TO BREAK DOWN BY THURSDAY AS A LOW PRESSURE SYSTEM
STRENGTHENS OVER THE WESTERN UNITED STATES. MEANWHILE...WARM AIR
WILL BE ADVECTED INTO CENTRAL INDIANA AHEAD OF A SURFACE
LOW...RESULTING IN ABOVE NORMAL TEMPERATURES. PRECIP ASSOCIATED
WITH THAT SURFACE LOW WILL INITIALLY FALL IN THE FORM OF RAIN ON
THURSDAY NIGHT AND FRIDAY...AND THEN TRANSITION TO A RAIN/SNOW MIX
AS COLDER AIR FILTERS IN BEHIND THE ASSOCIATED COLD FRONT.
&&
.AVIATION /DISCUSSION FOR THE 14/12Z TAF ISSUANCE/...
ISSUED AT 609 AM EST SAT DEC 14 2013
LIFR CONDITIONS CAN BE EXPECTED WELL INTO THIS AFTERNOON AS BANDS
OF SNOW CONTINUE TO PASS OVER TAF SITES. SNOW SHOWERS WILL WEAKEN
AFTER SAT 21Z AND THEN COME TO AN END AROUND SUN 00Z. MINIMAL
IMPROVEMENTS IN VISIBILITIES CAN BE EXPECTED BY THIS EVENING...BUT
DO NOT EXPECT CEILINGS TO IMPROVE TO MVFR CATEGORY UNTIL AFTER SUN
06Z. WINDS WILL BECOME NORTHWESTERLY THIS AFTERNOON AND STRENGTHEN
SLIGHTLY DURING THE EVENING HOURS WITH SUSTAINED SPEEDS OF
8 TO 12 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
INZ053>057-060>065-067>072.
WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR INZ021-
028>031-035>049-051-052.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
626 AM EST SAT DEC 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EST SAT DEC 14 2013
WV IMAGERY AND RAP ANALYSIS SHOW A LONG WAVE TROUGH OVER THE
CENTRAL CONUS...WITH MUCH OF THE ENERGY IN THE SOUTHERN STREAM
MOVING THROUGH THE SOUTHERN THIRD OF THE CONUS. CLOSER TO THE UPPER
GREAT LAKES...A SHORTWAVE IS CURRENTLY TRACKING THROUGH SOUTHERN
MANITOBA AND INTO NORTHERN MINNESOTA AT THIS TIME...WITH A BROAD
AREA OF MOISTURE AHEAD OF THIS WAVE IN MN/WI/MI. AT THE SURFACE...A
ELONGATED AREA OF 1034MB HIGH PRESSURE STRETCHES FROM LAKE WINNIPEG
EAST-SOUTHEAST INTO SOUTHWEST QUEBEC...WHILE A TROUGH STRETCHES
NORTHEAST INTO SOUTHERN WISCONSIN FROM A 1007MB LOW IN NORTH
CENTRAL TEXAS. THE FORCING FROM THE SHORTWAVE AND INCREASED
MOISTURE AHEAD OF IT HAS LED TO -SHSN OVER MINNESOTA OVER THE LAST
SEVERAL HOURS AND THEY HAVE EXPANDED EAST INTO WESTERN WISCONSIN.
CLOSER TO THE U.P. 850MB TEMPS OF -17 TO -20C OVER THE CWA HAS
COMBINED WITH LIGHT NORTHEAST TO EASTERLY FLOW TO LEAD TO LIGHT
LAKE EFFECT SNOW SHOWERS OVER SOUTH CENTRAL LAKE SUPERIOR. IT HAS
FINALLY STARTED TO PUSH TO THE NORTHEAST AS THE LOW LEVEL WINDS HAVE
SWITCHED TO THE SOUTH. INVERSION HEIGHTS OF 3-4KFT ON 00Z KINL
SOUNDING AND 08Z KMQT VAD PROFILE ARE LIKELY THE MAIN LIMITING
FACTOR TO THE SNOW OVERNIGHT...IN ADDITION TO THE VARIABLE LOW LEVEL
FLOW. FARTHER SOUTH...LAKE ENHANCED SNOWFALL CONTINUES OFF
LAKE MICHIGAN IN EAST CENTRAL AND PARTS OF NORTHEAST WISCONSIN.
THERE WAS A STRONGER BAND AFFECTING OCONTO EARLIER IN THE
NIGHT...BUT IT HAS SINCE WEAKENED. THERE ARE SOME HINTS THAT THE
LAKE EFFECT IS NEARING MENOMINEE...BUT VISIBILITIES THERE ARE STILL
10SM.
MUCH OF THE FORECAST FOR THE SHORT TERM WILL FOCUS ON THE SHORTWAVE
AND LAKE EFFECT/ENHANCED SNOWFALL UNDER VEERING LOW LEVEL WINDS TO
THE SOUTHEAST THROUGH THE EVENING. AS THE SHORTWAVE SHIFTS INTO
WISCONSIN AND UPPER MICHIGAN THIS AFTERNOON...A INVERTED TROUGH WILL
DEVELOP NORTHWEST FROM THE LOW MOVING INTO THE MID ATLANTIC STATES.
00Z KINL SOUNDING FAIRLY REPRESENTATIVE OF THE LIMITED MOISTURE IN
LOWER LEVELS ROTATING AROUND THE HIGH (VERY DRY BETWEEN
940-700MB)...BUT EXPECT THAT TO GIVEWAY FROM SOUTHWEST TO NORTHEAST
LATE THIS MORNING AND CONTINUE INTO THE AFTERNOON. ALREADY FAIRLY
MOIST ON THE 00Z KGRB SOUNDING AND WITH THAT CLOSE PROXIMITY AND
LIGHT NORTHEASTERLY PUSH AROUND THE HIGH...THE DRIER AIR SHOULD GIVE
AWAY FAIRLY EASILY. FORCING FROM THE SHORTWAVE AND INVERTED TROUGH
WILL DEVELOP LIGHT SNOW ACROSS MUCH OF THE AREA LATE THIS MORNING
BEFORE DIMINISHING FROM WEST TO EAST THROUGH THE LATE AFTERNOON AND
EVENING HOURS. FOCUS TURNS TO LAKE EFFECT/ENHANCED SNOWFALL.
FIRST...THE SNOW OVER SOUTH CENTRAL LAKE SUPERIOR SHOULD CONTINUE
TO DRIFT NORTHWEST THIS MORNING AND BRIEFLY CROSS THE KEWEENAW
PENINSULA BEFORE MOVING BACK INTO LAKE SUPERIOR. THE MAIN AREA OF
CONCERN IS FOR LAKE ENHANCED SNOWFALL ALONG THE BAY OF GREEN BAY.
INDICATIONS ARE THERE FROM THE MODELS AND THE DELTA-T VALUES
OF 18 TO 21 SUPPORT IT...BUT HIGHER RESOLUTION MODELS WHICH
TRADITIONALLY OVER DO QPF ARE STRUGGLING TO PUT OUT ANY SIGNIFICANT
VALUES OVER SOUTHERN MENOMINEE AND SOUTHEAST DELTA COUNTIES TODAY.
HAVE A FEELING THAT THE STRUGGLE TO PUT OUT ANY DECENT QPF IS
RELATED TO THE LOW LEVEL SHEAR INDICATED BY THE MODELS. THIS CAN BE
SEEN AT THE PRESENT TIME IN EAST CENTRAL WISCONSIN WHERE WINDS ARE
PREDOMINATELY EASTERLY IN THE LOWER LEVELS AND LAKE ENHANCEMENT IS
OCCURRING. BUT FARTHER NORTH ACROSS THE BAY OF GREEN BAY...THE DRIER
AIR COMBINED WITH WINDS VARYING IN DIRECTION DEPENDING ON LEVEL
(850MB VEERING SOUTHEAST...925MB STAYING MAINLY EASTERLY...AND
SURFACE WINDS NORTHEASTERLY) HAS BEEN LIMITING DEVELOPMENT THUS
FAR. THIS WILL LIKELY CONTINUE THROUGH THE AFTERNOON UNTIL THE
TROUGH DEVELOPS ACROSS THE AREA AND FOCUSES WINDS OUT OF THE
SOUTHEASTERLY DIRECTION THIS EVENING. AM WONDERING IF THIS SHEAR
WILL BE ENOUGH TO LIMIT ANY REAL STRONG LAKE ENHANCED BANDS. IN
ADDITION...INVERSION HEIGHTS AROUND MENOMINEE THIS MORNING ARE
AROUND 5-6KFT AND REMAINS THROUGH MUCH OF TODAY...LIKELY LIMITING
STRONG ENHANCEMENT AND HIGHER TOTALS. THEY ARE A LITTLE HIGHER
AROUND ESCANABA (6-7KFT THIS AFTERNOON/EVENING) AND WHEN COMBINED
WITH THE MORE UNIFORM FLOW THIS EVENING...THINK THAT IS WHEN THEY
WILL HAVE THE BEST OPPORTUNITY FOR MODERATE SNOWFALL. ON THE
POSITIVE SIDE...MUCH OF THE LAKE ENHANCED FORCING IS IN OR JUST
BELOW THE DGZ AND ALLOW FOR SNOW RATIOS TO BE HIGHER AND AROUND 20
TO 1. UNFORTUNATELY...DEALING WITH AROUND 20-1 SNOW RATIOS MAKES FOR
A DIFFICULT TIME ON PINNING DOWN AMOUNTS ON THESE LOWER END QPF
AMOUNTS. MODEL COBB SNOW AMOUNTS ARE ALL OVER THE BOARD WITH 12Z NAM
FOR KESC GIVING AROUND 3.5-4IN AND OUR LOCAL 00Z WRF-ARW HAS
3-3.8IN...WHILE THE 08Z RAP IS GIVING 1.3IN THROUGH 02Z. 03Z SREF
MEAN HAS 2.3-3.0 AND THINK THAT IS A REASONABLE COMPROMISE. AMOUNTS
FOR KMNM HAVE A SIMILAR RANGE...WITH THE HIGHEST AMOUNTS FROM THE
MODELS OF 4-5INCHES...BUT THOSE RUNS HAD 2IN OF ACCUMULATION ALREADY
EVEN THOUGH IT HASN/T EVEN STARTED SNOWING. THEREFORE...OPTED TO
LOWER AMOUNTS ABOUT AN INCH AND MAY NEED TO DO MORE IF THE SNOW
STRUGGLES TO DEVELOP THIS MORNING. STILL THINK THE HIGHEST AMOUNTS
WILL BE OVER THE GARDEN PENINSULA...WHERE AMOUNTS COULD REACH 5
INCHES.
OVERALL VERY UNCERTAIN ON SNOWFALL AMOUNTS FOR MENOMINEE AND DELTA
COUNTIES TODAY...LARGELY DUE TO THE LOW LEVEL SHEAR THAT LOOKS LIKE
IT WILL OCCUR. A LITTLE MORE CONFIDENCE IN PORTIONS OF DELTA AS
WINDS BECOME MORE FAVORABLE THIS EVENING AND THERE IS LESS
SHEAR...BUT EVEN THEN THE BANDS WILL LIKELY BE MOVING ENOUGH TO THE
EAST TO LIMIT SIGNIFICANT ACCUMULATIONS. THEREFORE...WILL KEEP THE
ADVISORY GOING FOR NOW (WITH WEAKER WORDING AND GREATER RANGE IN
TOTALS TO SHOW UNCERTAINTY) SINCE THEY SHOULD SEE SOME SNOW AND
ALLOW THE DAY SHIFT TO ASSESS THE SITUATION THROUGH THE MORNING.
WITH THE UNCERTAINTY...DID NOT EXPAND ADVISORY TO SOUTHERN
SCHOOLCRAFT FOR TONIGHT EVEN THOUGH THERE TOTALS ARE IN THE SAME
RANGE AS SOUTHERN DELTA COUNTY.
A SURFACE LOW LOOKS TO DEVELOP ALONG THE SURFACE TROUGH OVER
NORTHERN LAKE SUPERIOR TONIGHT AS A SECONDARY AND STRONGER
SHORTWAVE DROPS OVER LAKE SUPERIOR. THE FLOW AROUND THE LOW WILL
KEEP MUCH OF THE LAKE EFFECT AWAY FROM THE LAKE SUPERIOR SHORELINES
THIS EVENING...BEFORE WINDS SHIFT TO THE WEST-NORTHWEST OVER THE
WESTERN LAKE OVERNIGHT WITH THE LOW MOVING INTO THE EASTERN LAKE.
THEREFORE...SHOULD SEE LAKE EFFECT INCREASING OVER THE WESTERN HALF
OF THE CWA OVERNIGHT WITH THAT WINDSHIFT AND THE INTENSIFYING LOW
OVER THE NORTHERN/EASTERN LAKE. INVERSION HEIGHTS DO LOOK TO IMPROVE
TO AROUND 10KFT OVER THE WESTERN LAKE OVERNIGHT AND WITH THE HELP OF
THE ADDITIONAL MOISTENING TODAY FROM THE SURFACE TROUGH...THAT AREA
SHOULD BE ABLE TO REALIZE THOSE FAIRLY HIGH INVERSION HEIGHTS.
850MB TEMPS FALL FROM -16C AT 06Z TO -20C BY 12Z SUNDAY...SO LAKE
INSTABILITY IS PRESENT AND BUFKIT SOUNDINGS ARE SHOWING LAKE INDUCED
CAPES IN THE 400-600 J/KG RANGE. IN ADDITION...THE EXTRA
FORCING FROM THE SHORTWAVE (INCREASING MID LEVEL Q-VECTOR
CONVERGENCE) WILL PRODUCE A CONDUCIVE PERIOD FOR LAKE EFFECT
SNOWFALL. THUS...WOULD EXPECT THERE TO BE A FAIRLY DECENT BURST OF
SNOW AFTER ABOUT 06Z FROM THE PORKIES UP THROUGH THE KEWEENAW
PENINSULA AS THE WINDS SHIFT TO THE WNW. HIGH RESOLUTION MODELS
AGREE FAIRLY WELL WITH THIS TIMING AND WILL BUMP POPS UP TO 100
PERCENT IN THOSE AREAS OVERNIGHT. WITH MUCH OF THE FORCING RIGHT
WITHIN AND A LITTLE ABOVE THE DGZ...SHOULD SEE FAIRLY DECENT SNOW
RATIOS (AROUND 20-22 TO 1) AND WOULD EXPECT AT LEAST OF COUPLE HOUR
PERIOD OF 1 IN/HR SNOWFALL AFTER 06Z IN SOME LOCATIONS.
THEREFORE...HAVE TRENDED THE SNOWFALL FORECAST UP A LITTLE BIT WITH
A GENERAL 1-3 INCH AMOUNTS AND HAVE THE HIGHEST VALUES OVER THE
HIGHER TERRAIN FROM THE PORKIES THROUGH THE KEWEENAW.
OVER THE REST OF THE CWA...WINDS WILL BE SHIFTING FROM
SOUTH-SOUTHEAST TO WESTERLY AS THE LOW MOVES TO THE EAST THROUGH
THE NIGHT. EXPECT THE ONGOING LAKE EFFECT OFF LAKE MICHIGAN TO
FOLLOW THAT EASTWARD PUSH THROUGH THE NIGHT AND LARGELY INFLUENCING
DELTA COUNTY IN THE EVENING AND THEN SCHOOLCRAFT AND SOUTHERN LUCE
COUNTIES DURING THE OVERNIGHT HOURS. THE EXPECTED EASTWARD MOVEMENT
OF THE LAKE ENHANCED SNOWFALL SHOULD LIMIT THE SNOWFALL AMOUNTS OVER
MOST OF THOSE AREAS TO A QUICK 1-3IN OF SNOW TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 403 AM EST SAT DEC 14 2013
NAM SHOWS A CLOSED 500 MB LOW NORTH OF LAKE SUPERIOR 12Z SUN WHICH
MOVES SOUTHEAST ON SUN. ANOTHER UPPER TROUGH DIGS SOUTHEAST INTO THE
AREA FOR MON NIGHT. NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE
12Z MON MOVING INTO THE AREA WITH SOME DEEPER MOISTURE WHICH REMAINS
INTO MON NIGHT. LAKE EFFECT SNOW WILL CONTINUE THIS PERIOD FOR
SUNDAY INTO SUNDAY EVENING WITH COLD AIR IN NORTHWEST AND NORTH LAKE
EFFECT SNOW BELTS. ON MONDAY...THERE COULD BE SOME LAKE ENHANCEMENT
MON AFTERNOON AND EVENING OFF OF LAKE MICHIGAN AND HAVE THIS COVERED
WITH LIKELY POPS IN THE EASTERN CWA FOR SOUTHWEST WIND FLOW. HAVE
LIKELY POPS MON NIGHT ACROSS THE KEWEENAW FOR WEST FLOW LAKE EFFECT
SNOW BELTS. DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR
TEMPERATURES.
IN THE EXTENDED...GFS AND ECMWF SHOW A BROAD 500 MB TROUGH OVER THE
CENTRAL AND EASTERN U.S. 12Z TUE. THIS TROUGH PULLS EAST 12Z WED
WITH SFC HIGH PRESSURE ALONG THE MISSISSIPPI RIVER VALLEY. SFC LOW
PRESSURE MOVES INTO THE CENTRAL PLAINS 12Z THU. GFS AND ECMWF SHOW A
500 MB TROUGH OVER THE NORTHERN PLAINS AND DESERT SW 12Z FRI. COLDER
THAN NORMAL TEMPERATURES LOOK TO CONTINUE THIS FORECAST PERIOD
EXCEPT FOR A BRIEF RESPITE ON THU INTO FRIDAY BEFORE COLD AIR
ARRIVES AGAIN. STILL LOOKS COLD ENOUGH WITH A WARM FRONT TO THE
SOUTH AND WARM AIR JUST TO THE SOUTH TO KEEP THE PCPN AS SNOW ON
THU...BUT WILL HAVE TO WATCH THIS AS THERE IS A LOW POSSIBILITY OF
SOME MIXED PCPN IN THE FAR SOUTH. BASICALLY...LAKE EFFECT SNOW WILL
CONTINUE THROUGH WED BEFORE SYSTEM KICKS OUT ON THU. COLD AIR THEN
ARRIVES AGAIN LATE ON FRIDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 626 AM EST SAT DEC 14 2013
A SHORTWAVE AND DEVELOPING INVERTED TROUGH MOVING ACROSS UPPER
MICHIGAN TODAY WILL LEAD TO INCREASING CHANCES OF LIGHT SNOW
SHOWERS AND LOWERING CEILINGS THROUGH THE DAY. EXPECT THE SNOW AND
LOWER CEILINGS TO IMPACT KIWD FIRST AND THEN SPREAD TO KCMX/KSAW
LATE INTO THE AFTERNOON AND EARLY EVENING. UPSTREAM OBS GENERALLY
INDICATE MVFR/VFR VISIBILITIES WITH THE LIGHT SNOW AND WILL
CONTINUE TO FOLLOW THAT TREND. A LITTLE UNCERTAIN ON HOW SOON THE
CEILINGS AT KIWD WILL GO DOWN DUE TO THE UNFAVORABLE EAST-SOUTHEAST
FLOW...SO HAVE HELD THEM UP UNTIL THE BEST SNOW OCCURS IN THE
AFTERNOON. FOR KCMX/KSAW THIS MORNING...THE LAKE EFFECT SNOW SHOWERS
THAT WERE IMPACTING KSAW WILL CONTINUE NW THROUGH NOON. THINK THE
SHOWERS WILL BRUSH OR MISS KCMX TO THE NORTHEAST...SO HAVE TRENDED
VISIBILITIES UP THIS MORNING AND KEPT CEILINGS AT MVFR. DID BRING
CEILINGS DOWN AT KSAW EARLIER THAN THE OTHER SITES DUE TO FAVORABLE
UPSLOPE SOUTHEAST FLOW LATE THIS AFTERNOON.
AS A LOW DEVELOPS ALONG THE TROUGH IN NORTHERN LAKE SUPERIOR THIS
EVENING AND THEN MOVES SOUTHEAST OVERNIGHT...EXPECT A COLD FRONT
TO SWEEP ACROSS UPPER MICHIGAN AND SHIFT WINDS TO THE NORTHWEST.
BELIEVE THERE WILL BE A STRONG LINE OF SNOW SHOWERS ALONG THIS
FRONT AND THEN TRANSITIONING TO LAKE EFFECT OVERNIGHT AND
CONTINUING INTO SUNDAY. MODELS HAVE DECENT AGREEMENT ON
TIMING...WITH IT SWEEPING THROUGH KIWD/KCMX BETWEEN 05-07Z SUNDAY
AND HAVE FOLLOWED THAT IDEA FOR THOSE SITES. THE UNFAVORABLE
WEST-NORTHWEST FLOW FOR KSAW SHOULD LEAD TO A TRANSITION TO VFR
CEILINGS/VISIBILITIES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EST SAT DEC 14 2013
HIGH PRESSURE OVER SOUTHERN ONTARIO EARLY THIS MORNING WILL MOVE
EAST INTO SOUTHWEST QUEBEC TODAY WHILE A LOW PRESSURE SYSTEM TAKING
SHAPE IN THE LOWER MISSISSIPPI VALLEY MOVES INTO THE MID ATLANTIC
STATES. WHILE THIS OCCURS...A LOW PRESSURE TROUGH WILL SETUP OVER
THE UPPER GREAT LAKES THIS AFTERNOON AND THEN DEVELOP INTO A WEAK
LOW TONIGHT BEFORE SHIFTING SOUTHEAST SUNDAY AFTERNOON INTO SUNDAY
NIGHT. EXPECT GENERALLY LIGHT WINDS ALONG THIS TROUGH TODAY AND
TONIGHT...BUT DO EXPECT THEM TO INCREASE OUT OF THE NORTHWEST ON
SUNDAY...WITH GUSTS TO 30KTS EXPECTED SUNDAY AFTERNOON/EVENING.
WINDS WILL QUICKLY DIMINISH LATE SUNDAY NIGHT BEFORE INCREASING OUT
OF THE SOUTHWEST ON MONDAY (GUSTS TO 30KTS) AHEAD OF A CLIPPER LIKE
LOW MOVING SOUTHEAST THROUGH SOUTHERN CANADA AND BRUSHING THE UPPER
GREAT LAKES ON MONDAY NIGHT AND TUESDAY. AS THE COLD FRONT SWEEPS
THROUGH ON MONDAY NIGHT...EXPECT WINDS TO SHIFT TO THE NORTHWEST
AND BE IN THE 20-30KT RANGE. THERE COULD EVEN BE SOME GALE FORCE
GUSTS TO 35KTS TUESDAY INTO TUESDAY NIGHT. ANOTHER QUICK HIGH
PRESSURE RIDGE WILL MOVE IN ON WEDNESDAY AND DIMINISH WINDS AHEAD
OF LOW DEVELOPING IN THE CENTRAL PLAINS AND EXPECTED TO MOVE
THROUGH THE GREAT LAKES REGION ON THURSDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST SUNDAY FOR MIZ013.
LAKE EFFECT SNOW ADVISORY UNTIL 8 PM CST THIS EVENING FOR MIZ012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...07
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
630 AM CST SAT DEC 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CST SAT DEC 14 2013
HAS BEEN QUITE A NIGHT IN TERMS OF LAKE EFFECT SNOW. RECEIVED A
REPORT A SHORT TIME AGO OF CLOSE TO A FOOT OF SNOW FROM A VERY
SMALL LAKE EFFECT SNOW BAND THAT PARKED OVER THE CITY OF SUPERIOR
FRIDAY EVENING. AFTER BEING IN ONE LOCATION FOR SEVERAL HOURS...IT
HAD BASICALLY STARTED ITS PROGRESSION ALONG THE NORTH SHORE BY
MIDNIGHT. THE HEAVIEST SNOW BAND WAS JUST NORTHEAST OF GOOSEBERRY
FALLS STATE PARK AS OF 4 AM. THE HIGH RESOLUTION MODELS ARE
GENERALLY IN AGREEMENT THAT THE BANDS WILL CONTINUE TO MEANDER
ACROSS THE NORTH SHORE OF LAKE SUPERIOR TODAY. THE HRRR SEEMS TO
HAVE A FAIRLY DECENT HANDLE ON THE CURRENT LOCATION OF THE
HEAVIEST SNOW BAND...WITH LOCALLY HEAVY SNOW ACROSS LAKE COUNTY
THROUGH THE MORNING. THE HRRR AND MOST OF THE OTHER MODELS THEN
MIGRATE THAT AREA OF HEAVIER SNOW INTO COOK COUNTY FOR THE
AFTERNOON. GOING TO CONTINUE THE LAKE EFFECT SNOW ADVISORY...WITH
LOCALIZED 5 TO 7 INCHES...BUT COULD POTENTIALLY SEE MORE THAN THAT
IF THE BANDS PARK OVER ONE LOCATION FOR TOO LONG. WILL HAVE TO
KEEP A CLOSE EYE ON IT TODAY.
MEANWHILE...LIGHT SNOW WILL PROGRESS ACROSS MUCH OF THE NORTHLAND
TODAY. AMOUNTS WILL GENERALLY BE LIGHT WITH 1 TO 2 INCHES FOR MOST
AREAS.
ARCTIC HIGH PRESSURE WILL THEN BUILD DOWN BEHIND THE DEPARTING
WEAK LOW PRESSURE SYSTEM TONIGHT. HAVE DROPPED TEMPS
CONSIDERABLY...ESPECIALLY ACROSS THE NORTH. COULD SEE SOME -20S
ESPECIALLY ACROSS THE NORTH.
HAVE ALSO DROPPED TEMPS A BIT FOR SUNDAY...AS IT APPEARS SOME
NORTHERN LOCATIONS MAY STRUGGLE TO REACH ZERO DESPITE PARTIAL
SUNSHINE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 415 AM CST SAT DEC 14 2013
FAST MOVING SHORTWAVE WILL MOVE ACROSS THE CWA EARLY IN THE PERIOD
WITH A PERIOD OF LIGHT SNOW OCCURRING LATE SUNDAY NIGHT INTO EARLY
TUESDAY. BEYOND THAT THE UPPER JET WILL STRETCH ACROSS THE REGION
THROUGH EARLY THURSDAY. WITHIN THAT TIME PASSING SNOW SHOWERS ARE
POSSIBLE...MAINLY OVER THE NRN AND ERN CWA. ALL MED RANGE MDLS
SUPPORT THE MOVEMENT OF ANOTHER MID LVL TROF OVER THE REGION
THUR/FRI. POPS INCREASE LATE IN THE WEEK HOWEVER DOMINANT NRN BRANCH
OF UPPER JET WILL KEEP ANY SIGNIFICANT SFC DEVELOPMENT SOUTH AND
EAST OF THE AREA. TEMPS WILL MODERATE TO SOME EXTENT DURING THE EARLY
WEEK ESPECIALLY OVER THE SOUTH AND WEST AS FAST FLOW ALOFT KEEPS ANY
REINFORCING ARCTIC AIR FOCUSED JUST NORTH OF THE REGION ACROSS SRN
CANADA. LATE IN THE WEEK A DEVELOPING SFC LOW WILL MOVE FROM THE
PLAINS INTO THE LOWER GT LAKES. THIS SYSTEM WILL PULL ANOTHER SURGE
OF COLDER AIR SOUTH FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 551 AM CST SAT DEC 14 2013
LOW VFR/MVFR CEILINGS WILL TRANSITION TO MAINLY MVFR THIS MORNING
AS LIGHT SNOW CROSSES THE REGION. VISIBILITY MAY LOWER TO IFR AT
TIMES BUT CONFIDENCE NOT VERY HIGH AT THIS POINT. HIGHEST PROB OF
SNOW WILL BE THROUGH 00Z BEFORE INVERTED SFC TROUGH MOVES EAST AND
MOISTURE DECREASES. CYCLONIC MOIST FLOW WILL CONTINUE BEHIND
SYSTEM TONIGHT SO CLOUDS WILL BE SLOW TO DECREASE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 11 -11 1 -7 / 70 30 10 30
INL 3 -21 -3 -10 / 70 10 10 40
BRD 11 -13 3 -4 / 80 10 10 40
HYR 17 -8 4 -9 / 80 30 10 20
ASX 17 -1 8 -4 / 60 50 30 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...LAKE EFFECT SNOW ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ012-
020-021.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM...CANNON
AVIATION...CANNON
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
539 AM CST SAT DEC 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM CST SAT DEC 14 2013
YET ANOTHER PROLONGED LIGHT SNOW EVENT IS ONGOING ACROSS THE AREA
THIS MORNING. FORCING FOR THIS IS RATHER WEAK AND BEST EVIDENCE
OF THIS IS PROBABLY THE FACT THAT A QUICK WALK OUTSIDE AT 230 AM
THIS MORNING REVEALED THAT THE MOON WAS STILL VISIBLE THROUGH ALL
THE SNOW AND CLOUDS! THE UPPER WAVE RESPONSIBLE FOR THE SNOW SHOWS
UP WELL WITH A PLOT OF POTENTIAL VORT OFF THE RAP AT H4 WHICH HAS
SHOWN A WEAK ANOMALY STEADILY PUSHING EAST ACROSS THE DAKOTAS THIS
MORNING. THIS PV FEATURE AS ALSO BEEN AIDED BY WEAK DIFFLUENCE
ALOFT WITHIN THE RIGHT ENTRANCE OF AN UPPER JET THE STRETCHES FROM
CENTRAL MN OVER TO NEW ENGLAND. SNOW REPORTS FALL OFF QUICKLY WEST
OF THE PV FEATURE OVER THE DAKOTAS...AND EXPECT THIS TREND TO
CONTINUE AS THIS WAVE WORKS ACROSS THE AREA TODAY. HRRR TIMING FOR
WORKING THE BACK EDGE OF THE SNOW ACROSS THE AREA MATCHES UP
FAIRLY WELL WITH THE RAPS TIMING OF THE PV FEATURE ACROSS THE
AREA...SO LET THE HRRR REFLECTIVITY FORECAST GUIDE POPS FOR TODAY.
THIS RESULTED IN A SLIGHT SLOWING OF THE POP DECREASE FROM WEST TO
EAST THAT WILL START AROUND 12Z OUT BY THE SODAK BORDER. THIS
SYSTEM WILL QUICKLY MOVE OUT OF THE EASTERN CWA THIS
EVENING...WITH TONIGHT EXPECTED TO BE MAINLY SNOW FREE. THE ONLY
POTENTIAL EXCEPTION TO THIS WILL BE LATE TONIGHT OUT IN FAR
WESTERN MN AS NEXT SHIELD OF WAA PRECIP WILL BE MOVING ACROSS THE
DAKOTAS...THOUGH BETTER PRECIP CHANCES WITH THIS LOOK TO ARRIVE
SUNDAY MORNING.
FOR CURRENT SNOW...CONTINUED TREND OF FAIRLY WIDESPREAD 1-2 INCHES
OF SNOW ACROSS THE ENTIRE AREA. ALL MODELS FROM THE HRRR AND
HOPWRF TO THE ECMWF/GFS SHOW FAIRLY WIDESPREAD TOTAL QPF AMOUNTS
BETWEEN 0.05 AND 0.10 INCHES...WHICH SHOULD BE ABLE TO TRANSLATE
INTO THE 1-2 INCH RANGE. THOUGH BUFKIT THERMAL PROFILES WITH THEIR
DEEP DENDRITIC GROWTH ZONES WOULD SUGGEST SEEING SNOW RATIOS IN
EXCESS OF 20:1...WEAK NATURE OF FORCING HAS PREVENTED ICE CRYSTAL
GROWTH FROM GETTING OUT OF HAND...KEEPING SNOW TYPE AS MAINLY FINE
CRYSTALS. HENCE WHY 12-15 HOURS OF LIGHT SNOW IS ONLY EXPECTED TO
NET 1 TO 2 INCHES OF ACCUMULATIONS.
FOR TEMPERATURES...TODAY WILL BE SIMILAR TO FRIDAY AS CLOUDS
COMBINED WITH NORTH WINDS BRINGING DOWN THE ARCTIC AIR THAT IS
SITTING UP IN NRN MN HELPING TO LIMIT DIURNAL RANGES TODAY TO 5
DEGREES OR LESS. TONIGHT...THE ARCTIC AIR WILL FINALLY BE PUSHING
INTO THE MPX AREA...WHICH SHOULD ALLOW JUST ABOUT EVERYONE TO DIP
BELOW ZERO. TRENDED FORECAST LOWS TONIGHT TOWARD BIAS CORRECTED
VERSIONS OF THE ECMWF AND MET...WHICH RESULTED IN KNOCKING CLOSE 5
DEGREES OFF OF THE EXISTING FORECAST. IF WE CAN GET SKIES TO CLEAR
OUT...THEN TEMPS COULD GET COLDER STILL...ESPECIALLY OVER CENTRAL
MN WHERE LOWS IN THE -20S BELOW ZERO WOULD NOT BE OUT OF QUESTION.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 312 AM CST SAT DEC 14 2013
COLD NW FLOW WILL PERSIST ON THE BACKSIDE OF THE POTENT ERN
SEABOARD STORM OR SUN INTO MON AS RIDGING DEVELOPS OVER THE W
COAST. WHILE SFC HIGH PRES OVER S-CENTRAL CANADA...EXTENDING SWD
INTO THE DAKOTAS AND MN/WI...SEVERAL WAVES DRIVING SEWD WITHIN THE
FLOW ALOFT WILL ENCOUNTER ENHANCED H7-H5 LIFT AND A SWATH OF
RELATIVELY DEEPER MOISTURE. THIS COMBINATION WILL PRODUCE LIGHT
SNOW FOR SUN INTO MON. THOUGH WAA WILL COMMENCE DURG THE DAY ON
MON...THIS WAVE LOOKS TO EXIT THE REGION FAST ENOUGH SUCH THAT ANY
AND ALL PRECIP FROM IT SHALL REMAIN AS ALL -SN. SNOWFALL
ACCUMULATIONS WILL GENERALLY RANGE 1-2 INCHES...THOUGH IT IS
POSSIBLE THAT FAR ERN PORTIONS OF THE MPX CWFA /SPECIFICALLY...A
FEW WRN WI COUNTIES/ MAY RECEIVE UPWARDS OF 3-4 INCHES. STILL A
LITTLE BIT OF TIME TO IRON OUT THESE DETAILS.
MORE EXTENSIVE HIGH PRES WITH WARMER TEMPERATURES WILL CROSS THE
REGION TUE INTO WED...RESULTING IN HIGHER H5 HEIGHTS PRODUCING MAX
TEMPS INTO THE LOW-MID 20S WITH NO PRECIP EXPECTED.
ATTENTION THEN STILL IS FOCUSED ON THE END OF THE WEEK DUE TO THE
DEVELOPMENT OF A POTENT STORM SYSTEM DEVELOPING IN THE LEE OF THE
ROCKIES. AIDING THE DEVELOPMENT WILL BE THE WRN CONUS RIDGE
SHIFTING ACRS THE COUNTRY...PLACING THE SRN JET OVER THE
CYCLOGENESIS REGION AND ALLOWING A TRACK FOR IT TO MOVE NE. THERE
IS STILL MUCH UNCERTAINTY WITH REGARDS TO THE TRACK AND THE AMOUNT
OF WARM AIR ENTRAINED WITHIN THE SYSTEM. ATTM...THE TRACK OF THE
LOW PRES CENTER REMAINS S OF THE MPX CWFA...WHICH WOULD INDICATE
THAT THE PREVAILING P-TYPE IS -SN. HAVE ADVERTISED AS SUCH
ALTHOUGH THERE IS THE CAVEAT THAT IF THE TRACK SHIFTS FURTHER
N...THEN MULTIPLE P-TYPES MAY WELL BE INTRODUCED IN LATER
FORECASTS. THE SYSTEM DOES LOOK TO BE RATHER QUICK... TRACKING
FROM THE CO REGION NEWD INTO THE GREAT LAKES IN ABOUT 24 HRS. WITH
DEEP LONGWAVE TROUGHING AIDING ITS MOVEMENT...THE PRONOUNCED NW
FLOW BEHIND THIS SYSTEM WILL BRING DOWN ANOTHER ROUND OF ARCTIC
AIR STARTING THU NIGHT AND LASTING NOT ONLY FRIDAY BUT ALSO INTO
THE WEEKEND. SO...ALTHOUGH THERE IS LITTLE CONFIDENCE IN THE
DETAILS...THE OVERALL SCENARIO OF SEEING A POTENT WINTER STORM
FOLLOWED BY MUCH COLDER AIR IS LOOKING MORE REALISTIC BY THE MODEL
RUN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 513 AM CST SAT DEC 14 2013
CLOUD TOPS BEGINNING TO WARM ACROSS WRN MN AS LIGHT SNOW THAT HAS
BEEN FALLING ALL NIGHT IS BEGINNING TO COME TO AN END OUT TO THE
WEST. EXISTING TAFS HAD A PRETTY GOOD HANDEL ON TIMING OF THE
DEPARTURE OF -SN...WITH ONLY MINOR TIMING REFINEMENTS MADE TO GET
TAFS MORE IN LINE WITH THE TIMING OF THE HRRR. CIG HEIGHTS ARE A
BIT MORE TRICKY AS CIGS HAVE BEEN TRENDING TOWARD VFR ACROSS THE
AREA AS THE -SN HAS BEGUN TO LIGHTEN UP. HOWEVER...EXTENSIVE MVFR
CIGS SIT ACROSS THE ERN DAKOTAS AND EXPECT THESE CIGS TO MOVE
BACK INTO THE AREA AS LOW LEVEL WINDS BECOME WRLY THIS MORNING
INTO THE AFTERNOON. IMPROVED CIGS TO START...WITH LOWER CONDITIONS
RETURNING LATE MORNING INTO THE AFTERNOON AS CLOUDS OVER THE
DAKOTAS WORK EAST. FOR TONIGHT...LOTS OF CLOUD COVER CAN BE FOUND
UPSTREAM INTO SRN CANADA...SO WE MAY MAINTAIN MOSTLY CLOUDY
CONDITIONS AS THE GFS SHOWS...THOUGH SAFELY IN THE VFR CATEGORY.
KMSP...LOWEST VSBYS ALL NIGHT ACROSS THE AREA WITH THE -SN HAVE
BEEN RIGHT OVER THE TWIN CITIES...AS MOST SURROUNDING SITES HAVE
MAINTAINED A 3-5SM VSBY WITH -SN. MAY SEE IFR VIS -SN CONTINUE
BEYOND 13Z...BUT THOSE KINDS OF VIS RESTRICTIONS SHOULD BE DONE BY
15Z. CIG FORECAST MAY BE OVERDONE TODAY AS CURRENT CHAOTIC STATE
OF CIG HEIGHTS DOES NOT HELP YIELD MUCH CONFIDENCE IN CIGS THROUGH
TODAY. AT THE VERY LEAST...HARD PRESSED AT THE MOMENT TO SEE CIGS
EVER DROPPING BELOW 018.
/OUTLOOK FOR KMSP/
SUN...MVFR CIGS PSBL. CHC OF -SN LATE. WINDS LGT AND VRB.
MON...MVFR CIGS PSBL. CHC OF -SN EARLY. WINDS SW 5-10 KTS.
TUE...VFR. WINDS WNW 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...JPC
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
416 AM CST SAT DEC 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CST SAT DEC 14 2013
HAS BEEN QUITE A NIGHT IN TERMS OF LAKE EFFECT SNOW. RECEIVED A
REPORT A SHORT TIME AGO OF CLOSE TO A FOOT OF SNOW FROM A VERY
SMALL LAKE EFFECT SNOW BAND THAT PARKED OVER THE CITY OF SUPERIOR
FRIDAY EVENING. AFTER BEING IN ONE LOCATION FOR SEVERAL HOURS...IT
HAD BASICALLY STARTED ITS PROGRESSION ALONG THE NORTH SHORE BY
MIDNIGHT. THE HEAVIEST SNOW BAND WAS JUST NORTHEAST OF GOOSEBERRY
FALLS STATE PARK AS OF 4 AM. THE HIGH RESOLUTION MODELS ARE
GENERALLY IN AGREEMENT THAT THE BANDS WILL CONTINUE TO MEANDER
ACROSS THE NORTH SHORE OF LAKE SUPERIOR TODAY. THE HRRR SEEMS TO
HAVE A FAIRLY DECENT HANDLE ON THE CURRENT LOCATION OF THE
HEAVIEST SNOW BAND...WITH LOCALLY HEAVY SNOW ACROSS LAKE COUNTY
THROUGH THE MORNING. THE HRRR AND MOST OF THE OTHER MODELS THEN
MIGRATE THAT AREA OF HEAVIER SNOW INTO COOK COUNTY FOR THE
AFTERNOON. GOING TO CONTINUE THE LAKE EFFECT SNOW ADVISORY...WITH
LOCALIZED 5 TO 7 INCHES...BUT COULD POTENTIALLY SEE MORE THAN THAT
IF THE BANDS PARK OVER ONE LOCATION FOR TOO LONG. WILL HAVE TO
KEEP A CLOSE EYE ON IT TODAY.
MEANWHILE...LIGHT SNOW WILL PROGRESS ACROSS MUCH OF THE NORTHLAND
TODAY. AMOUNTS WILL GENERALLY BE LIGHT WITH 1 TO 2 INCHES FOR MOST
AREAS.
ARCTIC HIGH PRESSURE WILL THEN BUILD DOWN BEHIND THE DEPARTING
WEAK LOW PRESSURE SYSTEM TONIGHT. HAVE DROPPED TEMPS
CONSIDERABLY...ESPECIALLY ACROSS THE NORTH. COULD SEE SOME -20S
ESPECIALLY ACROSS THE NORTH.
HAVE ALSO DROPPED TEMPS A BIT FOR SUNDAY...AS IT APPEARS SOME
NORTHERN LOCATIONS MAY STRUGGLE TO REACH ZERO DESPITE PARTIAL
SUNSHINE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 415 AM CST SAT DEC 14 2013
FAST MOVING SHORTWAVE WILL MOVE ACROSS THE CWA EARLY IN THE PERIOD
WITH A PERIOD OF LIGHT SNOW OCCURRING LATE SUNDAY NIGHT INTO EARLY
TUESDAY. BEYOND THAT THE UPPER JET WILL STRETCH ACROSS THE REGION
THROUGH EARLY THURSDAY. WITHIN THAT TIME PASSING SNOW SHOWERS ARE
POSSIBLE...MAINLY OVER THE NRN AND ERN CWA. ALL MED RANGE MDLS
SUPPORT THE MOVEMENT OF ANOTHER MID LVL TROF OVER THE REGION
THUR/FRI. POPS INCREASE LATE IN THE WEEK HOWEVER DOMINANT NRN BRANCH
OF UPPER JET WILL KEEP ANY SIGNIFICANT SFC DEVELOPMENT SOUTH AND
EAST OF THE AREA. TEMPS WILL MODERATE TO SOME EXTENT DURING THE EARLY
WEEK ESPECIALLY OVER THE SOUTH AND WEST AS FAST FLOW ALOFT KEEPS ANY
REINFORCING ARCTIC AIR FOCUSED JUST NORTH OF THE REGION ACROSS SRN
CANADA. LATE IN THE WEEK A DEVELOPING SFC LOW WILL MOVE FROM THE
PLAINS INTO THE LOWER GT LAKES. THIS SYSTEM WILL PULL ANOTHER SURGE
OF COLDER AIR SOUTH FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1225 AM CST SAT DEC 14 2013
SNOW OVERSPREADING AREA FROM THE WEST. CURRENTLY CONDITIONS VARY
FROM VFR TO MVFR...EXPECT THAT CIGS AND VSBYS WILL SLOWLY FALL TO
MVFR FOR MOST LOCATIONS. KDLH MAY ALSO FALL TO LIFR WITH THE LAKE
EFFECT SNOW BAND EXPECTED TO MOVE ACROSS THE TERMINAL IN THE NEXT
FEW HOURS. MVFR TO TEMPORARY IFR CONDITIONS IN LIGHT SNOW EXPECTED TO
PERSIST THROUGH APPROXIMATELY 21Z...BEFORE LIFTING TO MVFR CIGS
WITH VFR CIGS FOR THE EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 11 -11 1 -7 / 70 30 10 30
INL 3 -21 -3 -10 / 70 10 10 40
BRD 11 -13 3 -4 / 80 10 10 40
HYR 17 -8 4 -9 / 80 30 10 20
ASX 17 -1 8 -4 / 60 50 30 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...LAKE EFFECT SNOW ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ012-
020-021.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM...CANNON
AVIATION...CANNON
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
413 AM CST SAT DEC 14 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM CST SAT DEC 14 2013
YET ANOTHER PROLONGED LIGHT SNOW EVENT IS ONGOING ACROSS THE AREA
THIS MORNING. FORCING FOR THIS IS RATHER WEAK AND BEST EVIDENCE
OF THIS IS PROBABLY THE FACT THAT A QUICK WALK OUTSIDE AT 230 AM
THIS MORNING REVEALED THAT THE MOON WAS STILL VISIBLE THROUGH ALL
THE SNOW AND CLOUDS! THE UPPER WAVE RESPONSIBLE FOR THE SNOW SHOWS
UP WELL WITH A PLOT OF POTENTIAL VORT OFF THE RAP AT H4 WHICH HAS
SHOWN A WEAK ANOMALY STEADILY PUSHING EAST ACROSS THE DAKOTAS THIS
MORNING. THIS PV FEATURE AS ALSO BEEN AIDED BY WEAK DIFFLUENCE
ALOFT WITHIN THE RIGHT ENTRANCE OF AN UPPER JET THE STRETCHES FROM
CENTRAL MN OVER TO NEW ENGLAND. SNOW REPORTS FALL OFF QUICKLY WEST
OF THE PV FEATURE OVER THE DAKOTAS...AND EXPECT THIS TREND TO
CONTINUE AS THIS WAVE WORKS ACROSS THE AREA TODAY. HRRR TIMING FOR
WORKING THE BACK EDGE OF THE SNOW ACROSS THE AREA MATCHES UP
FAIRLY WELL WITH THE RAPS TIMING OF THE PV FEATURE ACROSS THE
AREA...SO LET THE HRRR REFLECTIVITY FORECAST GUIDE POPS FOR TODAY.
THIS RESULTED IN A SLIGHT SLOWING OF THE POP DECREASE FROM WEST TO
EAST THAT WILL START AROUND 12Z OUT BY THE SODAK BORDER. THIS
SYSTEM WILL QUICKLY MOVE OUT OF THE EASTERN CWA THIS
EVENING...WITH TONIGHT EXPECTED TO BE MAINLY SNOW FREE. THE ONLY
POTENTIAL EXCEPTION TO THIS WILL BE LATE TONIGHT OUT IN FAR
WESTERN MN AS NEXT SHIELD OF WAA PRECIP WILL BE MOVING ACROSS THE
DAKOTAS...THOUGH BETTER PRECIP CHANCES WITH THIS LOOK TO ARRIVE
SUNDAY MORNING.
FOR CURRENT SNOW...CONTINUED TREND OF FAIRLY WIDESPREAD 1-2 INCHES
OF SNOW ACROSS THE ENTIRE AREA. ALL MODELS FROM THE HRRR AND
HOPWRF TO THE ECMWF/GFS SHOW FAIRLY WIDESPREAD TOTAL QPF AMOUNTS
BETWEEN 0.05 AND 0.10 INCHES...WHICH SHOULD BE ABLE TO TRANSLATE
INTO THE 1-2 INCH RANGE. THOUGH BUFKIT THERMAL PROFILES WITH THEIR
DEEP DENDRITIC GROWTH ZONES WOULD SUGGEST SEEING SNOW RATIOS IN
EXCESS OF 20:1...WEAK NATURE OF FORCING HAS PREVENTED ICE CRYSTAL
GROWTH FROM GETTING OUT OF HAND...KEEPING SNOW TYPE AS MAINLY FINE
CRYSTALS. HENCE WHY 12-15 HOURS OF LIGHT SNOW IS ONLY EXPECTED TO
NET 1 TO 2 INCHES OF ACCUMULATIONS.
FOR TEMPERATURES...TODAY WILL BE SIMILAR TO FRIDAY AS CLOUDS
COMBINED WITH NORTH WINDS BRINGING DOWN THE ARCTIC AIR THAT IS
SITTING UP IN NRN MN HELPING TO LIMIT DIURNAL RANGES TODAY TO 5
DEGREES OR LESS. TONIGHT...THE ARCTIC AIR WILL FINALLY BE PUSHING
INTO THE MPX AREA...WHICH SHOULD ALLOW JUST ABOUT EVERYONE TO DIP
BELOW ZERO. TRENDED FORECAST LOWS TONIGHT TOWARD BIAS CORRECTED
VERSIONS OF THE ECMWF AND MET...WHICH RESULTED IN KNOCKING CLOSE 5
DEGREES OFF OF THE EXISTING FORECAST. IF WE CAN GET SKIES TO CLEAR
OUT...THEN TEMPS COULD GET COLDER STILL...ESPECIALLY OVER CENTRAL
MN WHERE LOWS IN THE -20S BELOW ZERO WOULD NOT BE OUT OF QUESTION.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 312 AM CST SAT DEC 14 2013
COLD NW FLOW WILL PERSIST ON THE BACKSIDE OF THE POTENT ERN
SEABOARD STORM OR SUN INTO MON AS RIDGING DEVELOPS OVER THE W
COAST. WHILE SFC HIGH PRES OVER S-CENTRAL CANADA...EXTENDING SWD
INTO THE DAKOTAS AND MN/WI...SEVERAL WAVES DRIVING SEWD WITHIN THE
FLOW ALOFT WILL ENCOUNTER ENHANCED H7-H5 LIFT AND A SWATH OF
RELATIVELY DEEPER MOISTURE. THIS COMBINATION WILL PRODUCE LIGHT
SNOW FOR SUN INTO MON. THOUGH WAA WILL COMMENCE DURG THE DAY ON
MON...THIS WAVE LOOKS TO EXIT THE REGION FAST ENOUGH SUCH THAT ANY
AND ALL PRECIP FROM IT SHALL REMAIN AS ALL -SN. SNOWFALL
ACCUMULATIONS WILL GENERALLY RANGE 1-2 INCHES...THOUGH IT IS
POSSIBLE THAT FAR ERN PORTIONS OF THE MPX CWFA /SPECIFICALLY...A
FEW WRN WI COUNTIES/ MAY RECEIVE UPWARDS OF 3-4 INCHES. STILL A
LITTLE BIT OF TIME TO IRON OUT THESE DETAILS.
MORE EXTENSIVE HIGH PRES WITH WARMER TEMPERATURES WILL CROSS THE
REGION TUE INTO WED...RESULTING IN HIGHER H5 HEIGHTS PRODUCING MAX
TEMPS INTO THE LOW-MID 20S WITH NO PRECIP EXPECTED.
ATTENTION THEN STILL IS FOCUSED ON THE END OF THE WEEK DUE TO THE
DEVELOPMENT OF A POTENT STORM SYSTEM DEVELOPING IN THE LEE OF THE
ROCKIES. AIDING THE DEVELOPMENT WILL BE THE WRN CONUS RIDGE
SHIFTING ACRS THE COUNTRY...PLACING THE SRN JET OVER THE
CYCLOGENESIS REGION AND ALLOWING A TRACK FOR IT TO MOVE NE. THERE
IS STILL MUCH UNCERTAINTY WITH REGARDS TO THE TRACK AND THE AMOUNT
OF WARM AIR ENTRAINED WITHIN THE SYSTEM. ATTM...THE TRACK OF THE
LOW PRES CENTER REMAINS S OF THE MPX CWFA...WHICH WOULD INDICATE
THAT THE PREVAILING P-TYPE IS -SN. HAVE ADVERTISED AS SUCH
ALTHOUGH THERE IS THE CAVEAT THAT IF THE TRACK SHIFTS FURTHER
N...THEN MULTIPLE P-TYPES MAY WELL BE INTRODUCED IN LATER
FORECASTS. THE SYSTEM DOES LOOK TO BE RATHER QUICK... TRACKING
FROM THE CO REGION NEWD INTO THE GREAT LAKES IN ABOUT 24 HRS. WITH
DEEP LONGWAVE TROUGHING AIDING ITS MOVEMENT...THE PRONOUNCED NW
FLOW BEHIND THIS SYSTEM WILL BRING DOWN ANOTHER ROUND OF ARCTIC
AIR STARTING THU NIGHT AND LASTING NOT ONLY FRIDAY BUT ALSO INTO
THE WEEKEND. SO...ALTHOUGH THERE IS LITTLE CONFIDENCE IN THE
DETAILS...THE OVERALL SCENARIO OF SEEING A POTENT WINTER STORM
FOLLOWED BY MUCH COLDER AIR IS LOOKING MORE REALISTIC BY THE MODEL
RUN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1012 PM CST FRI DEC 13 2013
REFLECTIVITY HAS FLOURISHED SINCE LAST UPDATE A FEW HOURS AGO.
INTERESTINGLY...THE HI RES MODELS TRY TO SHOW THIS BROAD AREA OF
LIGHT SNOW ESSENTIALLY DISAPPEARING BEFORE COMING BACK AROUND 10Z.
I DONT SEE A LOGICAL REASON FOR THIS...SO KEPT THE SNOW IN THE
FORECAST ACROSS THE AREA. LIFT IS STILL NOT IMPRESSIVE...BUT THE
MODEL SOUNDINGS DO INDICATE A VERY DEEP DENDRITIC GROWTH ZONE
WHICH WILL ONLY HELP LOWER VSBYS AND ACCUMULATION TO OCCUR. EXPECT
GENERALLY A DUSTING TO TWO INCHES ACROSS THE FA...WITH A FEW SPOTS
EXCEEDING TWO INCHES OF ACCUMULATION. CEILINGS HAVE RAPIDLY
LOWERED AT MOST SITES...AND SHOULD STAY DOWN THROUGH THE NIGHT.
WINDS OUT OF THE NORTHEAST WILL EVENTUALLY BACK TO NW BY
TOMORROW AFTN.
KMSP...SNOWFALL WITH CEILINGS CONTINUING TO FALL TO AROUND 015
OVERNIGHT IS EXPECTED. ONE TO TWO INCHES OF ACCUMULATION LIKELY BY
MIDDAY SUNDAY. HEAVIEST SNOW EXPECTED TO LIGHTEN UP AROUND
13Z...BUT VERY LIGHT SNOW COULD LINGER INTO THE AFTERNOON.
/OUTLOOK FOR KMSP/
SUN...MVFR CIGS PSBL. CHC OF -SN LATE. WINDS NW 5 KTS.
MON...MVFR CIGS PSBL. CHC OF -SN EARLY. WINDS SW 5-10 KTS.
TUE...VFR. WINDS WNW 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...JPC
AVIATION...SPD
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
528 AM CST Sat Dec 14 2013
.SHORT TERM...(Today through Sunday Night)
Issued at 313 AM CST SAT DEC 14 2013
Winter storm is departing the region early this morning. Lingering
areas of drizzle will cause some minor icing from eastern KS into
western and central MO through sunrise as temperatures continue to
drop below freezing. Additional snow amounts will be mostly confined
to areas around Boonville and Moberly where another inch or so is
possible through early morning. An additional band of light snow has
developed from Kansas City into Chillicothe and Kirksville in
response to a narrow band of frontogenesis. RAP and NAM hold on to
this frontogenetical forcing through about 12Z and drop it to near
I-70, so it`s conceivable for this area of snow to hold together for
a few more hours and produce a dusting of snow with local amounts up
to a half inch near and northeast of KC. With temperatures falling
below freezing, any light snow that falls may fall on top of ice
developing on roads as lingering water freezes. Will therefore keep
the advisory going through 9 am as planned.
Precipitation will taper off from northwest to southeast through mid
morning. There`s a slight chance for some flurries or freezing
drizzle to redevelop late this morning into early afternoon as the
main upper trough axis swings through and interacts with low-level
cold air advection. Anything that does fall through this period
should be very light if anything at all.
Clouds will begin to scatter out later this afternoon and evening
with low-level ridging building in from the west. This will allow
temperatures to drop well into the single digits across northern and
central MO where a decent snow pack exists. Temperatures will begin
to moderate by Sunday and Sunday night with conditions returning to
near average.
.LONG TERM...(Monday through Friday)
Issued at 313 AM CST SAT DEC 14 2013
Monday - Tuesday:
General troughing across eastern Canada and the northern Great Lakes
will keep the area under benign northwest flow aloft. Nearer the
surface, downsloping westerly flow will allow temperatures to climb
where there is no snowpack. Highs across east central Kansas and
west central Missouri will rise into the mid to upper 40s whereas
across north central Missouri, where there is snowpack, highs will
only reach the mid to upper 30s. Tuesday a weak cold front will drop
through the area however this will have little effect on
temperatures as highs Tuesday should again range in the upper 30s to
upper 40s.
Wednesday:
The upper level pattern begins to shift on Wednesday becoming more
zonal across the region. Surface winds will also increase out of the
south providing for WAA and highs will be in the upper 30s to near
50. The next feature of interest, in the form of an upper level
trough, will move into the southwestern CONUS.
Thursday - Friday:
Models are in a bit of disagreement this far in the extended range.
However, the ECMWF, GFS and GEM all show the upper level shortwave
moving into the western Plains on Thursday and forcing a strong cold
front towards the area. Warm moist air streaming out ahead of this
front may produce light rain or drizzle on Thursday as high
temperatures move above average into the mid 40s to mid 50s. Models
depict rain changing to snow behind the front as it moves through
the area on Thursday night. The model differences occur on Friday as
the GFS stalls the front south of the area with snow continuing
through the day Friday whereas, the EC builds high pressure into the
area keeping conditions dry. On Friday, left the chance POPs in the
grids inherited by the initialization to account for the GFS
solution.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 528 AM CST SAT DEC 14 2013
Wintry precipitation has ended for the Kansas City and St. Joseph
areas. Lingering light snow and drizzle will end by 14Z for the DMO
area. IFR ceilings will likely lift to low-end MVFR shortly and
remain there for the remainder of the day.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR KSZ025-
057-060-102>105.
MO...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR
MOZ004>008-012>017-020>025-028>033-037>040-043>046-053-054.
&&
$$
SHORT TERM...Hawblitzel
LONG TERM...73
AVIATION...Hawblitzel
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1055 AM EST SAT DEC 14 2013
.SYNOPSIS...A STORM SYSTEM WILL TRACK FROM THE SOUTHERN MISSISSIPPI
VALLEY NORTHEAST ACROSS THE CAROLINAS AND MID ATLANTIC REGION
THROUGH THE WEEKEND. HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST
LATE SUNDAY THROUGH TUESDAY.
&&
.NEAR TERM /TODAY THROUGH TONIGHT/... AS OF 1055 AM SATURDAY...
LATEST REGIONAL ANALYSIS SHOWS A WARM FRONT ALONG THE COAST
GRADUALLY MOVING ONSHORE. LIGHT RAIN SHOWERS HAVE BEEN FORMING ALONG
THIS BOUNDARY AND MOVING INLAND AND NORTH ACROSS THE SOUTHERN
COASTAL PLAIN. FARTHER WEST...A LARGE SHIELD OF LIGHT TO MODERATE
RAIN...ASSOCIATED WITH THE LARGER SYNOPTIC SCALE TROUGH AND COMPLEX
SFC LOW PATTERN...IS STEADILY MOVING EWD ACROSS THE MOUNTAINS AND
APPROACHING THE WESTERN PIEDMONT. A TYPICAL WEDGE FRONT HAS BEEN
TAKIN SHAPE THE PAST FEW HOURS AND IS GENERALLY POSITIONED ACROSS
THE ERN FOOTHILLS/WRN PIEDMONT ATTM. THE NEAR-TERM MODELS SUCH AS
THE RAP AND HRRR HAVE A FAIRLY GOOD HANDLE ON THE PATTERN AND
REFLECT OUR CONCEPTUAL IDEA FOR THE REST OF TODAY. LOOK FOR THE RAIN
TO OUR W TO CONTINUE TO MOVE E AND EXPAND ACROSS OUR CWA AS THE DAY
PROGRESSES AS THE LARGER SCALE SYSTEM CONTINUES TO DRIFT E. THE
AFOREMENTIONED RAIN SHOULD FURTHER STRENGTHEN THE LOW LEVEL WEDGE
AND ASSOC BOUNDARY ACROSS WESTERN PIEDMONT...SO TEMPS THERE NOT
EXPECTED TO INCREASE MUCH FROM CURRENT READINGS IN THE U30S TO L40S.
MEANWHILE...THE WARM FRONT FARTHER EAST IS EXPECTED TO GRADUALLY
PUSH INLAND...WITH TEMPS ACROSS OUR E/SE ZONES CLIMBING THROUGH THE
50S AS THE AFTERNOON PROGRESSES. IN BETWEEN THESE TWO BOUNDARIES
ACROSS OUR CNTRL ZONES...TEMPS EXPECTED TO ONLY SLOWLY RISE INTO THE
UPPER 40S TO PERHAPS LOWER 50S.
IN TERMS OF PRECIP...AS ELUDED TO...THE STEADIER LIGHT/MOD PRECIP
ENTERING OUR WRN ZONES WILL CONTINUE TO GRADUALLY SPREAD EWD...SO
THROUGH EARLY AFTERNOON...LOOK FOR RAIN TO BECOME DEVELOP AND BECOME
STEADY ACROSS OUR FAR W/NW ZONES (TRIAD)...WHILE FURTHER E...THE
RAIN WILL BE MORE SCATTERED AND SHOWERY IN NATURE. THEN LATER THIS
AFTERNOON...LOOK FOR THE RAIN TO BECOME STEADY ACROSS MUCH OF OUR
CWA AS THE LOW LEVEL JET AND LARGER SCALE FORCING CURRENTLY TO OUR W
SHIFTS E ACROSS OUR AREA. BY THIS EVENING...THE PRECIP ACROSS OUR
ERN ZONES MAY BECOME MORE CONVECTIVE IN NATURE WITH THE POTENTIAL
FOR A FEW HEAVIER DOWNPOURS AS THE AFOREMENTIONED LOW LEVEL JET AND
LARGER SYNOP SCALE FORCING ENCOUNTERS THE COASTAL BOUNDARY WHICH
SHOULD BE POSITIONED SOMEWHERE ALONG OR TO THE EAST OF I-95 BY THAT
TIME. FORECAST SOUNDINGS HOWEVER SHOW WHAT LITTLE INSTABILITY THERE
IS TO BE ELEVATED...SO IMPACTS W/CONVECTION...AT LEAST AS IT APPEARS
AT THIS POINT...SHOULD BE LIMITED TO SCATTERED HEAVY DOWNPOURS AND
PERHAPS A BRIEF WIND GUST OR TWO BELOW SVR LIMITS. NONETHELESS...
THESE SCATTERED HEAVIER DOWNPOURS MAY RESULT IN BRIEF PERIODS OF LOW
VISIBILITY AND WATER PONDING IN THE TYPICAL POOR DRAINAGE AREAS.
PRECIP EXPECTED TO END ACROSS OUR WRN ZONES BY 8 PM OR SO...AND
ACROSS OUR ERN ZONES SHORTLY AFT MIDNIGHT. -NP
WILL TAPER DOWN POPS WNW TO ESE LATE TONIGHT. MODEL SOUNDINGS SHOW
THE LOW LEVELS REMAINING VERY MOIST AND STABLE... SO EXPECT LOW
CLOUDS AND FOG TO HOLD IN INTO THE OVERNIGHT HOURS... BEFORE FINALLY
LIFTING AND MIXING OUT AS THE SYSTEM CONGEALS INTO A SINGLE LOW JUST
OFF NYC TOWARD SUNRISE SUNDAY. LOWS FROM 33 NW TO 47 SE. -GIH
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM SATURDAY...
AFTER SOME MORNING CLOUDINESS ASSOCIATED WITH THE WEAK SURFACE
TROUGH TRAILING FROM THE COASTAL LOW OFF NYC... THE ENSUING
DOWNSLOPE LOW LEVEL FLOW WILL HELP DRY OUT THE LOWER TROPOSPHERE...
AS INCREASING DEEP LAYER SUBSIDENCE IN THE WAKE OF THE DEPARTING
BROAD TROUGH AXIS HELPS DRY AND STABILIZE THE MID-UPPER LEVELS.
EXPECT PLENTY OF SUNSHINE BY THE AFTERNOON HOURS. THICKNESSES DO
FALL DURING THE DAY (MUCH OF WHICH IS A FUNCTION OF COOLING AT 925-
850 MB WITH A MORE TYPICAL DIURNAL TREND NOTED BELOW 925 MB ALBEIT
WITH SHALLOW MIXING)... BUT THE INCOMING AIR MASS IS MODIFIED AND
SOURCED FROM OUR WSW... AND LATE-DAY THICKNESSES ARE STILL JUST
SLIGHTLY BELOW NORMAL. HIGHS 51-57... CLOSE TO SEASONAL NORMALS.
LOWS 26-33 AS A PORTION OF THE SURFACE HIGH NOSES IN FROM THE SW
CAUSING WINDS TO BECOME LIGHT WITH MOSTLY CLEAR SKIES FACILITATING
RADIATIONAL COOLING. -GIH
&&
.LONG TERM /MONDAY THROUGH FRIDAY NIGHT/...
AS OF 330 AM SATURDAY...
MONDAY AND MONDAY NIGHT: THE LATEST LONG RANGE GUIDANCE CONTINUES TO
INDICATE DRY/BENIGN WEATHER THROUGH THE UPCOMING WORK WEEK...WITH
THE NEXT CHANCE FOR PRECIPITATION PERHAPS NOT UNTIL NEXT WEEKEND.
WEAK HIGH PRESSURE WILL BUILD INTO THE REGION SUN NIGHT/MON IN THE
WAKE OF A COLD FRONTAL PASSAGE...WITH HIGHS ON MONDAY COOLER THAN
SUNDAY...RANGING FROM THE UPPER 40S TO LOWER 50S. LOWS MON NIGHT IN
THE UPPER 20S TO NEAR 30F.
TUESDAY THROUGH WEDNESDAY NIGHT: EXPECT SOME DEGREE OF WARMING ON
TUE VIA SOUTHWEST LOW-LEVEL FLOW AND WARM ADVECTION ASSOC/W A
TIGHTENING MSLP/HEIGHT GRADIENT IN ADVANCE OF A POTENT SHORTWAVE AND
ATTENDANT CLIPPER LOW APPROACHING THE UPPER GREAT LAKES. THE
AFOREMENTIONED SHORTWAVE ENERGY DIGGING SOUTHEAST FROM CANADA TO THE
UPPER GREAT LAKES MON NIGHT/TUE WILL PROGRESS ACROSS THE LOWER GREAT
LAKES/NEW ENGLAND TUE NIGHT AND EARLY WED BEFORE MOVING OFFSHORE NEW
ENGLAND LATE WED. THE GFS/ECMWF GUIDANCE DIFFER ON THE AMPLITUDE OF
THIS SYSTEM...RESULTING IN SOME UNCERTAINTY W/REGARD TO MAX/MIN
TEMPERATURES ACROSS CENTRAL NC TUE/WED. THE GFS SUGGESTS A MORE
AMPLIFIED WAVE WITH STRONGER WARM ADVECTION ON TUE IN ADVANCE OF
IT...AND STRONGER COLD ADVECTION IN THE WAKE OF IT TUE NIGHT/WED...
WHILE THE ECMWF IS WEAKER AND MORE MODERATE WITH TEMPERATURES.
EITHER WAY...DRY CONDITIONS WILL PREVAIL WITH FORCING FOR ASCENT
REMAINING WELL NORTH OF THE REGION. WILL INDICATE HIGHS IN THE
MID/UPPER 50S ON TUE...LOWS IN THE MID 30S TUE NIGHT...AND HIGHS IN
THE LOWER/MID 50S ON WED.
THURSDAY THROUGH FRIDAY NIGHT...EXPECT RISING HEIGHTS ALOFT ALONG
THE EASTERN SEABOARD AND INCREASING MOISTURE ACROSS THE MID-ATLANTIC
AND CAROLINAS IN ASSOC/W A SOUTHERLY RETURN FLOW ON THE WESTERN
PERIPHERY OF OFFSHORE HIGH PRESSURE. UPSTREAM OF THE REGION...
EXPECT TROUGHING ALOFT ACROSS THE CENTRAL CONUS AND ROCKIES...WITH A
STRENGTHENING FRONTAL ZONE EXTENDING FROM THE LOWER MIDWEST
NORTHEAST INTO THE OH VALLEY BY FRI/FRI NIGHT. BOTH THE GFS/ECMWF
AGREE WELL ON THE OVERALL PATTERN...WHICH WOULD SUGGEST A WARMING
TREND ALONG WITH INCREASING CLOUD COVER OVER CENTRAL NC. AT THIS
TIME...EXPECT ANY CHANCE FOR PRECIPITATION TO REMAIN WEST OF THE
MOUNTAINS THROUGH FRIDAY NIGHT. -VINCENT
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 650 AM SATURDAY...
HIGH CONFIDENCE IN DETERIORATING AVIATION CONDITIONS FROM WEST TO
EAST STARTING THIS MORNING AFTER 14Z. CURRENT CONDITIONS OVER
CENTRAL NC ARE GOOD WITH VFR VSBYS/SKIES... BUT AS A STRONG STORM
SYSTEM NOW OVER AR/LA TRACKS EASTWARD THEN NORTHEAST... CROSSING THE
DEEP SOUTH TOWARD THE CAROLINAS EARLY THIS MORNING THROUGH
TONIGHT... RAPID SATURATION WILL CAUSE CIGS/VSBYS TO DROP TO MVFR BY
13Z-17Z (FROM WRN TO ERN TAFS) IN WIDESPREAD RAIN... AND TO IFR FROM
17Z-21Z (WRN TO ERN TAFS)... OCCASIONALLY DROPPING TO LIFR. THESE
POOR AVIATION CONDITIONS WILL LAST THROUGH SUNSET. RAIN WILL END
WEST TO EAST BETWEEN 03Z AND 08Z AS THE FRONTAL SYSTEM MOVES
THROUGH... BUT IFR/LIFR CIGS/VSBYS IN FOG ARE LIKELY TO PERSIST
UNTIL AROUND 12Z... WHEN SURFACE WINDS BECOME FROM THE WEST OR WNW
LEADING TO THE ONSET OF DOWNSLOPE FLOW. LOW LEVEL WIND SHEAR WILL
POST A THREAT TO AVIATORS THROUGH TODAY AS SURFACE WINDS FROM THE
EAST OR ESE UNDER 12 KTS ARE TOPPED BY 30-40 KT WINDS AROUND 2000 FT
AGL FROM THE SW. THIS MAY CAUSE SIGNIFICANT HANDLING DIFFICULTY AND
MECHANICAL TURBULENCE FROM 14Z THROUGH 05Z.
LOOKING BEYOND 12Z SUNDAY MORNING... EXPECT RISING CIGS/VSBYS TO VFR
THROUGH 14Z. VFR CONDITIONS LIKELY TO HOLD FROM MIDDAY SUN THROUGH
WED AS HIGH PRESSURE BUILDS IN FROM THE SW. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...NP/HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...VINCENT
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS NORMAN OK
515 AM CST SAT DEC 14 2013
.DISCUSSION...
AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW.
&&
.AVIATION...
IMPROVING CONDITIONS ARE EXPECTED.
MAINLY MVFR CONDITIONS WITH PATCHES OF IFR CONDITIONS WILL CONTINUE
AT ALL SITES THROUGH AT LEAST 15Z. CONDITIONS WILL IMPROVE WEST TO
EAST 15-20Z. HAVE HIGH CONFIDENCE THAT ALL SITES WILL BE VFR BY 20Z.
GUSTY NORTH TO NORTHWEST WINDS CAN BE EXPECTED AT ALL SITES...
SLOWLY DIMINISHING AFTER 20Z...THEN WEAKENING SIGNIFICANTLY 22-24Z.
MBS
&&
.PREV DISCUSSION... /ISSUED 338 AM CST SAT DEC 14 2013/
DISCUSSION...
WARMER WEATHER OVER THE NEXT SEVERAL DAYS WILL BE THE MAIN WEATHER
STORY.
DENSE FOG ADVISORY ACROSS MAINLY SOUTHERN OKLAHOMA IS IN OKAY
SHAPE...THOUGH VISIBILITIES HAVE BEEN INCREASING RAPIDLY DUE TO
INCREASING LOW LEVEL WINDS AND COLD AIR ADVECTION BEHIND A COLD
FRONT THAT WAS NEAR A WAURIKA TO SEMINOLE LINE AT 330 AM. THE
ADVISORY GOES UNTIL 6 AM THIS MORNING AND MAY BE CANCELLED BEFORE
THEN AS VISIBILITIES SHOULD CONTINUE TO IMPROVE.
KEPT PATCHY DRIZZLE/PATCHY FREEZING DRIZZLE THIS MORNING EAST OF
I-35 AS LATEST RADARS INDICATED LIGHT ECHOES EAST OF WICHITA AND
NEAR TULSA. LATEST HRRR RUNS AND THE RADAR DATA SHOW THAT SOME OF
THIS VERY LIGHT PRECIPITATION MAY AFFECT LOCATIONS EAST OF I-35.
NO PROBLEMS ARE EXPECTED AS THE PRECIPITATION WOULD BE VERY LIGHT
AND MOST LIKELY EVAPORATE ON SURFACES DUE TO THE BRISK NORTH
WINDS.
TODAY WILL BE A BRISK AND COLDER DAY. CLOUDS WILL ERODE WEST TO
EAST WITH THE CLEARING LINE NEAR I-35 AROUND NOON. MODEL GUIDANCE
HIGHS IN THE MID 30S EAST OF I-35 TO THE UPPER 40S ACROSS FAR
WESTERN NORTH TEXAS WERE ACCEPTED.
TONIGHT...CLEAR AND SEASONABLY COLD CONDITIONS WILL OCCUR WITH
LOWS MAINLY IN THE 20S.
SUNDAY WILL BE SUNNY AND WARMER. THINK HIGHS WILL GET IN THE 50S
AREAWIDE...AND PERHAPS ABOVE 60 DEGREES ACROSS PARTS OF WESTERN
OKLAHOMA AND WESTERN NORTH TEXAS.
SUNDAY NIGHT THROUGH THURSDAY...A PERIOD OF WARM AND DRY CAN BE
EXPECTED. TEMPERATURES WILL GENERALLY BE 5 TO 15 DEGREES ABOVE
AVERAGE. HIGHS MAY GET ABOVE 70 DEGREES IN A FEW LOCATIONS.
THURSDAY NIGHT INTO FRIDAY...CONFIDENCE IS GROWING THAT MUCH
COLDER AIR WILL RETURN TO THE AREA WITH AN ARCTIC COLD FRONT.
WINTRY PRECIPITATION MAY RESULT. PRECIPITATION TYPES...
LOCATIONS...AND AMOUNTS REMAIN VERY UNCERTAIN. FOR NOW...KEPT LOW
PRECIPITATION CHANCES ACROSS THE AREA MAINLY ON FRIDAY.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 37 26 58 31 / 0 0 0 0
HOBART OK 43 25 56 27 / 0 0 0 0
WICHITA FALLS TX 46 26 61 30 / 0 0 0 0
GAGE OK 47 21 59 23 / 0 0 0 0
PONCA CITY OK 38 24 56 27 / 0 0 0 0
DURANT OK 40 28 53 33 / 0 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR OKZ043-
047-048-051-052.
TX...NONE.
&&
$$
25/17/17
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
925 AM EST SAT DEC 14 2013
.SYNOPSIS...
A COMPLEX LOW PRESSURE SYSTEM OVER THE LOWER MISSISSIPPI VALLEY
WILL MOVE NORTHEAST TODAY AND INTO THE CENTRAL APPALACHIANS BY
THIS EVENING. THE LOW DEEPENS AND MOVES OFF THE NEW ENGLAND COAST
BY SUNDAY MORNING. HIGH PRESSURE WILL BE OVER THE REGION MONDAY
AND TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 925 AM EST SATURDAY...
FIRST BAND OF SNOW EARLY THIS MORNING PRODUCED A LIGHT COATING TO
AROUND ONE INCH ACROSS THE NORTH....WHILE SCATTERED SHOWERS FELL
IN A FEW LOCATIONS. MIX BATCH OF PRECIPITATION ENTERING PORTION
OF CWA THIS MORNING. RECEIVED REPORTS OF SOME SLEET NEAR
INDEPENDENCE IN GRAYSON COUNTY AND ALSO NEAR LYH. HRRR AND
RNKWRFARW SHOWED PRECIPITATION STARTING IN THE SOUTHWEST
SPREADING NORTHEAST ACROSS THE REGION THIS MORNING INTO THIS
AFTERNOON. LOOKING AT TEMPERATURES PROFILES LOOKS LIKE A PERIOD OF
SNOW AND SLEET STILL APPEARS POSSIBLE ESPECIALLY DURING THE ONSET
IN THE SOUTH BEFORE CHANGING TO RAIN. MADE SOME ADJUSTMENTS TO
TEMPERATURES AND DEW POINTS WITH LATEST OBS AND TRENDS. ADDED SOME
FOG FOR THIS MORNING. WITH ACTIVE WEATHER EXPECT MORE CHANGES
LATER THIS MORNING.
AS OF 500 AM EST SATURDAY...
BAND OF SNOW...WELL AHEAD OF THE MAIN AREA OF SYNOPTIC LIFT WAS
MOVING NORTHEAST OUT OF THE COUNTY WARNING AREA AT 5AM. THIS WAS
THE BEGINNING OF THE BREAK IN PRECIPITATION. CLOUD HEIGHTS WERE
STILL LOWERING AND RETURNS ON THE RADAR SHOWED THE PRECIPITATION
THAT WAS AIDING IN THE SATURATION OF THE AIR MASS.
HRRR...LOCAL WRF AND BUFKIT WERE SIMILAR WITH THE TIMING OF THE
MAIN BATCH OF PRECIPITATION...STARTING IN THE SOUTHWEST COUNTY
WARNING AREA BY 9AM AND REACHING THE NORTHEAST COUNTIES BY NOON.
DURATION OF PRECIPITATION WILL BE LIMITED...WITH A WELL DEFINED
DRY SLOT SEEN ON THE NATIONAL RADAR MOSAIC. EXPECT DRY SLOT AND
END OF MUCH OF THE PRECIPITATION TO REACH THE WESTERN COUNTY
WARNING AREA DURING THE MID AFTERNOON...WITH THE PRECIPITATION
ENDING IN THE EAST BY 9PM.
STRONG ISENTROPIC LIFT WILL RESULT IN SOME DECENT PRECIPITATION
RATES. MODELS WERE SHOWING SOME DIABATIC COOLING DURING THE
AFTERNOON NORTH OF ROUTE 460. THIS WILL IMPACT PRECIPITATION TYPE.
EVEN WITH EVAPORATIVE COOLING BRINING THE THERMAL PROFILE BELOW
ZERO...BUFKIT SHOWED A WEAK WARM NOSE FOR MUCH OF THE DAY. HAVE
MORE SLEET IN THE FORECAST THAN EARLIER WHICH WILL LIMIT
ACCUMULATIONS BUT IF PRECIPITATION IS HEAVY ENOUGH...IT WOULD STAY
AS SNOW. BY AFTERNOON TEMPERATURES ALOFT ARE WARM ENOUGH TO SUPPORT
FREEZING RAIN. ALSO BY THEN THE DEPTH OF THE MOISTURE WILL
GRADUALLY BECOME TOO SHALLOW FOR CRYSTAL GROWTH.
STRONG FLOW OFF THE GULF OF MEXICO BRINGS PRECIPITABLE WATER
VALUES BACK ABOVE ONE HALF INCH. HAVE INCREASED AMOUNT OF RAIN IN
THE SOUTHEAST COUNTY WARNING AREA WHERE PRECIPITABLE WATER VALUES
ARE HIGHER. NET RESULT WAS NO CHANGE IN ADVISORY AREA OR TIMING.
NON-DIURNAL TEMPERATURE TREND EXPECTED TODAY AS ONSET OF
PRECIPITATION INITIALLY COOLS SURFACE TEMPERATURES. COLDER AIR
COMES IN TONIGHT AS THE SURFACE LOW DEEPENS OFF THE MID ATLANTIC
COAST AND BRINGS THE WIND AROUND TO THE WEST. UPSLOPE SNOW
SHOWERS WILL PERSIST IN THE FAVORED AREAS OF SOUTHEAST WEST
VIRGINIA.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 345 AM EST SATURDAY...
SHORT TERM PERIOD OF FORECAST WILL BE RATHER UNEVENTFUL AS BROAD
UPPER TROF REMAINS ANCHORED OVER THE UPPER GREAT LAKES. COLD WEST
TO NORTHWEST UPSLOPING WINDS SHOULD MAINTAIN ABUNDANT CLOUD COVER
AND THREAT FOR OCCASIONAL LIGHT SNOW SHOWERS WITH SPOTTY LIGHT
ACCUMULATIONS ACROSS THE WESTERN FLANKS OF THE APPALACHIANS SUNDAY
INTO MONDAY BEFORE FINALLY ABATING BY MONDAY NIGHT AS SURFACE RIDGE
MOVES SOUTHEAST OF THE AREA...ENDING UPSLOPING MOIST FETCH FROM OFF
THE UPPER GREAT LAKES AS SURFACE WINDS BACK INTO THE SOUTHWEST.
TEMPERATURES IN THE UPSLOPE AREAS WILL BE HARD PRESSED TO CLIMB MUCH
ABOVE FREEZING THROUGH THE ENTIRE SHORT TERM PERIOD DUE TO COOLING
FROM FORCED ASCENT AND PERSISTENT CLOUD COVER. HAVE MAINTAINED
PREVIOUS FORECAST THINKING OF GOING A BIT BELOW MOS GUIDANCE DURING
DAYTIME PERIODS...WHICH TYPICALLY OVERESTIMATES THE EXTENT OF
DAYTIME WARMING UNDER THESE CONDITIONS.
ELSEWHERE...ESPECIALLY IN DOWNSLOPING AREAS EAST OF THE BLUE RIDGE
WHERE SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE ENTIRE PERIOD...
DAYTIME HIGHS LIKELY TO CLIMB WELL INTO THE 40S TO LOWER 50S...AND
MOS GUIDANCE GENERALLY ACCEPTED IN THESE AREAS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 335 PM EST FRIDAY...
UNDER ZONAL FLOW AND SOUTHWEST FLOW...THE FORECAST AREA WILL WARM UP
TO NORMAL LEVELS TUESDAY. THE COLD FRONT...WHICH WILL BE MOVING
ACROSS THE OHIO VALLEY TUESDAY...IS A LITTLE SLOWER ON THE 12Z MODEL
RUNS. DESPITE IT BEING SLOWER...STILL LOOKING AT A MOSTLY DRY
FRONTAL PASSAGE AS HIGH PRESSURE BLOCKS MOISTURE RETURNS FROM THE
GULF. MODELS CONTINUE TO ADVERTISE UPSLOPE SNOW SHOWERS FOR WESTERN
GREENBRIER NORTHWARD FOLLOWING THE FRONTAL PASSAGE AND WITH A SHORT
WAVE TRACKING ACROSS THE CENTRAL APPALACHIANS TUESDAY NIGHT...TAPER
TO FLURRIES WEDNESDAY MORNING. A PRESSURE GRADIENT ALSO TIGHTENS
OVER THE AREA TUESDAY NIGHT INTO WEDNESDAY TO BRING WINDY/GUSTY
CONDITIONS TO THE AREA. A SUBSIDENCE INVERSION SHOULD KEEP THE
HIGHER WINDS ABOVE 3 KFT TUESDAY NIGHT. AS THE INVERSION BREAKS AND
CLOUDS ERODE WEDNESDAY...MIXING ACROSS THE ENTIRE FORECAST AREA IS
EXPECTED. WINDS ACROSS THE HIGHER ELEVATIONS MAY REACH WIND ADVISORY
CRITERIA. HIGH PRESSURE BUILDS OVER THE REGION WEDNESDAY NIGHT...
ALLOWING THE WINDS TO SUBSIDE. HIGH PRESSURE WILL THEN MOVE OFF THE
MID ATLANTIC COAST ON FRIDAY. THIS WILL ALLOW THE NEXT SYSTEM TO
APPROACH THE REGION NEXT WEEKEND.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
AS OF 715 AM EST SATURDAY...
CEILINGS WILL CONTINUE TO LOWER THIS MORNING AS MOISTURE INCREASES
AND A LOW PRESSURE SYSTEM OVER THE LOWER MISSISSIPPI VALLEY
APPROACHES FROM THE WEST. AS PRECIPITATION BEGINS...IT WILL COOL
AND MOISTEN THE AIR MASS WHICH WILL RESULT IN SNOW AND/OR SLEET
AT THE ONSET. AS SHOWN IN BUFKIT SOUNDINGS...THE PRECIPITATION
WILL BECOME PRIMARILY RAIN AT KROA/KDAN/KBCB/KBLF/KLYH BY
AFTERNOON BUT WILL STAY MOSTLY SNOW AT KLWB.
HIGH CONFIDENCE IN THE TIMING OF THE PRECIPITATION...MOVING IN
FROM THE WEST AROUND 8AM AND EXITING THE EAST AROUND 8PM. LESS
CONFIDENCE ABOUT THE EXACT PRECIPITATION TYPE...ESPECIALLY THIS
MORNING.
AS THE LOW MOVES OFFSHORE...WINDS WILL TURN TO THE WEST. THIS WILL
LEAD TO UPSLOPE IFR TO LIFR CLOUDS AND PRECIPITATION AT KBLF/KLWB.
CEILINGS WILL GRADUALLY LIFT EAST OF THE BLUE RIDGE...BUT CLOUDS
MAY NOT BECOME SCATTERED UNTIL AFTER THE 12Z END OF THE TAF
FORECAST PERIOD. THE UPSLOPE CLOUDS WILL HOLD IN OVER SOUTHEAST
WEST VIRGINIA THROUGH SUNDAY NIGHT.
HIGH PRESSURE EXPECTED TO BUILD INTO THE REGION FROM THE WEST
SUNDAY NIGHT INTO MONDAY...ALLOWING UPSLOPING CLOUDS TO GRADUALLY
ERODE OVER THE MOUNTAINS...BRINGING A RETURN TO VFR WEATHER WITH
UNRESTRICTED CONDITIONS...EVEN IN THE UPSLOPE AREAS...BY MIDDAY
MONDAY. DRY WEATHER WITH MAINLY VFR WEATHER IS THEN EXPECTED IN
MOST AREAS INTO MID WEEK...WITH PERHAPS THE EXCEPTION OF A PERIOD
OF SOME UPSLOPING CLOUDS WITH MVFR CEILINGS ACROSS THE WESTERN
FLANKS OF THE APPALACHIANS LATER TUESDAY INTO WEDNESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR VAZ018>020-
023-024-034-035.
NC...NONE.
WV...WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR WVZ044-045.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...WERT
LONG TERM...RCS
AVIATION...AMS/WERT
AREA FORECAST DISCUSSION
NWS ALBANY NY
126 PM EST SAT DEC 14 2013
.SYNOPSIS...
ARCTIC HIGH PRESSURE SITUATED ACROSS THE SAINT LAWRENCE VALLEY HAS
USHERED IN A VERY COLD AIR MASS INTO THE REGION. A WINTER STORM
TAKING SHAPE ACROSS THE OHIO VALLEY WILL TRACK TOWARD NEW ENGLAND
TONIGHT. THIS WILL SPREAD ACCUMULATING SNOW ACROSS THE REGION. THE
STORM WILL DEPART THE REGION BY SUNDAY AFTERNOON. EVEN COLDER AIR
WILL SURGE INTO THE REGION BEHIND THIS STORM ON MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1230 PM...NO CHANGES MADE TO THIS PART OF THE FORECAST...BUT
CHANGES MADE TO THE SHORT TERM SECTION.
.PREVIOUS DISCUSSION...
INCREASED POPS ACROSS THE SOUTHERN PORTION OF THE FORECAST AREA.
LIGHT SNOW IS OCCURRING ACROSS THE SOUTHEASTERN CATSKILLS...MID
HUDSON VALLEY AND LITCHFIELD COUNTY. RADAR RETURNS LOOK WEAK HOWEVER
METARS SHOW VISIBILITIES UNDER 3 MILES AND SOME UNDER 1 MILE.
ALSO ADJUSTED POPS SOME AS THE DAY PROGRESSES BRINGING CHANCES FOR
SNOW NORTHWARD THROUGH DAY. LATEST 06Z GUIDANCE AND HOURLY
RUC/HRRR CONTINUE ALONG THE SAME FORECAST THOUGHTS WITH WAA
ISENTROPIC LIFT EVOLVING ALONG A TIGHTENING BAROCLINIC ZONE ALONG
AND JUST NORTH OF THE NY STATE LINE. QPF/S CONTINUE TO SHOW A
SLIGHT INCREASE FROM PREVIOUS RUNS SO WE MADE SLIGHT ADJUSTMENTS
TO THE SNOWFALL FORECAST TODAY.
H2O VAPOR LOOP REVEALS OUR MAIN INGREDIENT FOR OUR WINTER STORM
WAS MOVING INTO THE TENNESSEE VALLEY. A STRENGTHENING UPPER JET IS
UNDERWAY ACROSS THE SOUTHERN CONUS PER SATELLITE WIND ESTIMATES
AND HOURLY RUC ANALYSIS WITH ANOTHER UPPER JET SEGMENT ACROSS THE
UPPER GREAT LAKES REGION. THIS NORTHERN PORTION OF THE JET IS
EXPECTED TO REMAIN CYCLONIC IN NATURE WHICH SUGGESTS THIS UPPER
LOW MAY TRACK A LITTLE FURTHER WEST AND HANGING ONTO THE INITIAL
SURFACE LOW LONGER BEFORE THE TRANSFER OCCURS OFF THE MID ATLANTIC
COAST. BROAD ISENTROPIC LIFT IN ADVANCE OF THESE FEATURES WAS
UNDERWAY ACROSS THE NY/PA BORDER AS BAROCLINICITY WAS INCREASING
JUST NORTH OF THE ARCTIC BOUNDARY. PER EXPERIMENTAL REFLECTIVITY
FORECASTS FROM A VARIETY OF MESOSCALE MODELS...ALONG WITH THE DRY
AIR IN PLACE...IT MAY TAKE MOST OF THE MORNING TO SATURATE THE
LOWER LEVELS FOR SNOW TO REACH THE GROUND /VIRGA/ NORTH OF I90 AS
LOW LEVEL AGEOSTROPIC FLOW REMAINS IN PLACE /MAGNITUDE IS NOT THAT
STRONG BUT IS VERY PERSISTENT/. USED A BLENDED APPROACH FOR HIGH
TEMPERATURES TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
WINTER STORM WARNING IN EFFECT FOR THE ENTIRE REGION...
AS OF 1230 PM...THE 12Z NAM AND GFS MODEL RUNS TRACK THE LOW FURTHER
NORTH WITH THE TRACK NOW FORECAST TO GO RIGHT OVER LONG ISLAND. THIS
SHOULD RESULT IN ADDITIONAL MID LEVEL WARMING SO HAVE ADJUSTED THE
WEATHER GRIDS TO INCLUDE MORE FREEZING RAIN AND SLEET AFTER 06Z
TONIGHT AND HAVE ALSO PUSHED THE NORTHERN EXTENT OF THE MIXED PCPN
ALL THE WAY INTO THE CENTRAL CATSKILLS...THE SOUTHEAST PART OF THE
CAPITAL DISTRICT...THROUGH ALL OF BERKSHIRE COUNTY AND JUST ACROSS
THE BORDER INTO EXTREME SOUTHERN VERMONT. THIS HAS RESULTED IN ONE
TO FOUR INCH REDUCTIONS IN THE AMOUNTS OF SNOW FORECAST IN THESE
AREAS...WITH THE GREATEST REDUCTIONS OCCURRING OVER LITCHFIELD...
DUTCHESS AND EASTERN ULSTER COUNTIES. IT HAS ALSO EXPANDED THE AREA
WHERE ICING WILL OCCUR. DESPITE THE SNOW REDUCTIONS...STILL ENOUGH
SNOW WITH ENOUGH ICING IS FORECAST TO CONTINUE THE WINTER STORM
WARNINGS IN ALL AREAS...INCLUDING THE SOUTHERN ZONES.
.PREVIOUS DISCUSSION...
PREVIOUS DISCUSSIONS HAVE DONE AN EXCELLENT JOB WITH THE
METEOROLOGICAL PARAMETERS SETTING UP FOR THIS FIRST WIDESPREAD
SIGNIFICANT WINTER EVENT FOR THE REGION. 00Z GUIDANCE ALONG WITH THE
RECENT ARRIVAL OF THE 06Z NAM/GFS CONTINUE TO INCREASE QPF AMOUNTS
ALONG WITH ENHANCED FGEN BANDS SEEN IN THE H850-H700 LAYER PER
PREVIOUS CSTAR RESEARCH. THESE BANDS ARE PROGGED TO BE A LITTLE
FURTHER NORTH AND PER COORDINATION FROM WPC AND SURROUNDING
WFOS...WE WILL UPGRADE THE ADVISORY AREA AND EXTEND THE WARNING
ACROSS THE ENTIRE CWFA. IT WILL BE CLOSE PER THE DEFINITION OF 7"
IN 12HRS OR 9" IN 24HRS BUT WITH A HIGH IMPACT WIDESPREAD EVENT
THE WARNING WAS EXPANDED. AS WARM ADVECTION OCCURS IN THE THERMAL
PROFILES...SOME OF THE PRECIP ACROSS DUTCHESS AND LITCHFIELD
COUNTIES WILL MIX WITH SLEET AND FREEZING RAIN LATE TONIGHT. ICE
ACCUMULATIONS UP TO TWO TENTHS OF AN INCH ARE POSSIBLE BEFORE THE
WARM AIR AT THE SURFACE ARRIVES TO RESULT IN A CHANGEOVER TO
MAINLY RAIN/RAIN SHOWERS LATER SUNDAY MORNING. SO TEMPERATURES
WILL BE STEADY TO SLOWLY RISING OVERNIGHT AS WE WILL SHOW A NON-
DIURNAL TEMPERATURE TREND OVERNIGHT.
THE OTHER COMPLICATED FACTOR TO THIS WILL BE TRANSITIONING
SNOW TO LIQUID RATIOS AS WE SHOULD INITIALLY BE RATHER HIGH WITH
15:1 RATIO THEN GRADUALLY DROPPING TOWARD CLIMATOLOGY OF 12:1 FOR
MOST OF THE REGION AND EVENTUALLY TOWARD 10:1 TOWARD SUNRISE
SUNDAY. THE CROSS SECTIONS NOW REVEAL WE WILL INDEED SEE THE BEST
LIFT OCCUR IN THE BEST DENDRITIC SNOW GROWTH REGION WHICH ALONG
WITH FGEN BANDS TO ENHANCE SNOWFALL RATES. IN FACT...D-THETA/DZ
SUGGESTS THE SMALL POTENTIAL FOR CONVECTIVE ELEMENTS BETWEEN 06Z-
12Z SUNDAY AND AS THE SECONDARY LOW DEVELOPS OFF THE NJ
COAST...THE DUCT FUNCTION POINTS TOWARD THE POTENTIAL FOR A
GRAVITY WAVE/S/.
PRECIP SHADOW IS INDEED STILL PLAUSIBLE TOO AS LOW-MID LEVEL EAST-
SOUTHEAST WINDS INCREASE SUGGESTING PRECIP SHADOW DOWNWIND OF THE
BERKS-TACONICS AND THE GREENS INTO PORTIONS OF WASHINGTON COUNTY.
THIS STORM DEEPENS SUNDAY AS IT TRACKS THROUGH THE SOUTHERN
PORTIONS OF THE GULF OF MAINE WITH DEFORMATION SNOW AXIS ACROSS
PORTIONS OF THE DACKS. WIND GUSTS WILL LIKELY INCREASE TOO WHICH
WILL RESULT IN SOME BLOWING AND DRIFTING OF THE SNOW.
FURTHERMORE...WIND CHILLS WILL LIKELY DIP WELL BELOW ZERO ACROSS
THE DACKS AS WE MAY NEED HEADLINES FOR THIS IN FUTURE FORECASTS.
SNOW WILL TAPER OFF THROUGH THE DAYLIGHT HOURS SUNDAY WITH SOME
LAKE RESPONSE SUNDAY NIGHT INTO PORTIONS OF THE DACKS...WESTERN
MOHAWK VALLEY AND CATSKILLS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
BEHIND THE DEPARTING WINTER STORM...HIGH PRESSURE WILL MOVE OVER
THE REGION FOR MONDAY. WITH A COLD NW FLOW IN PLACE...MAX TEMPS
WILL BE BELOW NORMAL...WITH TEENS TO MID 20S ACROSS THE REGION.
VERY COLD TEMP WILL CONTINUE INTO MONDAY NIGHT WITH SINGLE DIGITS
OVER MUCH OF THE AREA. SOME BELOW ZERO READINGS WILL OCCUR ACROSS
THE ADIRONDACKS AND GREEN MOUNTAINS.
CLOUDS WILL BEGIN TO INCREASE LATE MONDAY NIGHT...WITH A SLIGHT CHC
FOR SOME SNOW SHOWERS...AS A CLIPPER SYSTEM BEGINS TO APPROACH FROM
THE GREAT LAKES. THIS WEAK SYSTEM WILL BE QUITE MOISTURE STARVED.
STILL...THERE IS A CHANCE FOR SOME LIGHT SNOW ACROSS THE REGION FOR
TUESDAY INTO TUESDAY NIGHT AS THIS SYSTEM TRACKS ACROSS THE AREA.
ANY QPF LOOKS RATHER LIGHT...AND SNOWFALL WILL ONLY BE AN INCH OR
TWO FOR MOST PLACES. MAX TEMPS WILL CONTINUE TO BE CHILLY ON TUESDAY
WITH 20S OVER MUCH OF THE AREA...AND TEENS TO LOW 20S FOR TUESDAY
NIGHT.
SOME LAKE EFFECT SNOW WILL OCCUR ACROSS THE WESTERN ADIRONDACKS AND
WESTERN MOHAWK VALLEY BEHIND THIS CLIPPER SYSTEM FOR WED INTO WED
NIGHT. OTHERWISE...IT LOOKS DRY OVER MUCH OF THE AREA. TEMPS ON WED
WILL BE A LITTLE WARMER THAN RECENT DAYS...WITH MID 20S TO MID 30S.
HOWEVER...A REINFORCING SHOT OF COLD AIR LOOKS TO ARRIVE ON WED
NIGHT...WITH TEENS FOR THE AREA...AND TEMPS BACK INTO THE 20S FOR
THURSDAY.
THIS COLD SHOT LOOKS TO BE SHORT LIVED...AS HIGH PRESSURE QUICKLY
PASSES OVER THE AREA...AND THE PATTERN BEGINS TO SHIFT SOMEWHAT.
WHILE IT WILL BE DRY FOR THURSDAY...THE OVERALL FLOW STARTS TO
BECOME MORE OUT OF THE SW BOTH AT THE LOW LEVELS AND ALOFT. THIS
WILL TRANSPORT MUCH WARMER AND MORE MOIST AIR INTO THE REGION FOR
THE LATE WEEK PERIOD. MAX TEMPS LOOK TO REACH INTO THE 40S FOR
VALLEY AREAS BY FRIDAY. ALTHOUGH IT/S STILL RATHER FAR OUT IN
TIME...AN APPROACHING SLOW MOVING FRONTAL BOUNDARY LOOKS TO BRING A
PERIOD OF PLAIN RAIN TO THE REGION FOR LATE IN THE WEEK AND INTO THE
WEEKEND ACROSS THE ENTIRE REGION...EVEN THE HIGHER TERRAIN
AREAS...WITH A RETURN TO ABOVE NORMAL TEMPS EXPECTED INTO THE
WEEKEND.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
A STORM SYSTEM OVER THE OHIO VALLEY WILL CONTINUE TO MOVE
NORTHEASTWARD AS WE HEAD INTO THE EVENING AS THE ARCTIC HIGH
CONTINUES TO RETREAT NORTHWARD. SECONDARY DEVELOPMENT IS OCCURRING
ALONG THE MID ATLANTIC COAST EVIDENT BY PRESSURE FALLS. THE COASTAL
LOW WILL BECOME THE PRIMARY LOW AS WE HEAD THROUGH THE OVERNIGHT
HOURS AS IT TRACKS NORTHEAST AND STRENGTHENS. THIS LOW IS FORECAST
TO CROSS OVER EASTERN LONG ISLAND AND CAPE COD SUNDAY MORNING.
LIGHT SNOW WILL CONTINUE TO SPREAD NORTHWARD WITH MVFR-IFR
CONDITIONS MAINLY DUE TO VISIBILITIES. THE SNOW WILL BECOME
HEAVIER AS WE HEAD INTO THE EVENING HOURS AND THE LOW LEVEL JET
APPROACHES AND MOVES INTO THE REGION. CONDITIONS WILL DETERIORATE
TO IFR THEN TO LIFR OVERNIGHT. BASED ON THE TRACK OF THE COASTAL
LOW SOME WARMER AIR WILL WORK ALOFT RESULTING IN SLEET MIXING IN
WITH THE SNOW AT KPSF AND EVEN AT KALB FOR A BIT BEFORE THE
PRECIPITATION BEGINS TO TAPER OFF. HOWEVER AT KPOU A TRANSITION TO
SLEET AND EVENTUALLY TO FREEZING RAIN IS EXPECTED MAINLY AFTER
MIDNIGHT.
CONDITIONS WILL BEGIN TO IMPROVE SUNDAY MORNING AFTER SUNRISE AS LOW
MOVES UP THE NEW ENGLAND COAST AND PRECIPITATION TAPERS OFF. EXPECTING
WIDESPREAD MVFR MAINLY DUE TO CEILING BY AFTERNOON.
OUTLOOK...
SUN: HIGH OPERATIONAL IMPACT. SN.
SUN NIGHT-MON: LOW OPERATIONAL IMPACT. BREEZY.
MON NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
TUE-TUE NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
WED: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
NO HYDRO RELATED CONCERNS ARE EXPECTED THE NEXT 5 DAYS.
QPF FROM THIS UPCOMING EVENT WILL RANGE FROM ONE HALF INCH TO ONE
AND ONE QUARTER OF AN INCH WITH THOSE HIGHER VALUES ACROSS THE
TERRAIN INTO THE CATSKILLS...SOUTHERN GREENS AND PORTIONS OF THE
DACKS. MOST OF THIS WILL FALL IN THE FORM OF SNOW WITH THE
EXCEPTION ACROSS DUTCHESS AND LITCHFIELD COUNTIES WHERE A WINTRY
MIXTURE AND PERHAPS A PERIOD OF RAIN MAY RESULT LATE SATURDAY
NIGHT INTO SUNDAY MORNING. ANY LIQUID PRECIP SHOULD RESULT WITHIN
BANK RISES.
THEREAFTER...TEMPS WILL CONTINUE TO BE BELOW NORMAL AND ICE WILL
CONTINUE TO FORM AND THICKEN ON AREA RIVERS...STREAMS AND
PARTICULARLY LAKES THROUGH EARLY NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR CTZ001-013.
NY...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR NYZ032-033-
038>043-047>054-058>061-063>066-082>084.
MA...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR MAZ001-025.
VT...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR VTZ013>015.
&&
$$
SYNOPSIS...BGM
NEAR TERM...IAA/BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...IAA
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
110 PM EST SAT DEC 14 2013
.SYNOPSIS...
ARCTIC HIGH PRESSURE SITUATED ACROSS THE SAINT LAWRENCE VALLEY HAS
USHERED IN A VERY COLD AIR MASS INTO THE REGION. A WINTER STORM
TAKING SHAPE ACROSS THE OHIO VALLEY WILL TRACK TOWARD NEW ENGLAND
TONIGHT. THIS WILL SPREAD ACCUMULATING SNOW ACROSS THE REGION. THE
STORM WILL DEPART THE REGION BY SUNDAY AFTERNOON. EVEN COLDER AIR
WILL SURGE INTO THE REGION BEHIND THIS STORM ON MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1230 PM...NO CHANGES MADE TO THIS PART OF THE FORECAST...BUT
CHANGES MADE TO THE SHORT TERM SECTION.
.PREVIOUS DISCUSSION...
INCREASED POPS ACROSS THE SOUTHERN PORTION OF THE FORECAST AREA.
LIGHT SNOW IS OCCURRING ACROSS THE SOUTHEASTERN CATSKILLS...MID
HUDSON VALLEY AND LITCHFIELD COUNTY. RADAR RETURNS LOOK WEAK HOWEVER
METARS SHOW VISIBILITIES UNDER 3 MILES AND SOME UNDER 1 MILE.
ALSO ADJUSTED POPS SOME AS THE DAY PROGRESSES BRINGING CHANCES FOR
SNOW NORTHWARD THROUGH DAY. LATEST 06Z GUIDANCE AND HOURLY
RUC/HRRR CONTINUE ALONG THE SAME FORECAST THOUGHTS WITH WAA
ISENTROPIC LIFT EVOLVING ALONG A TIGHTENING BAROCLINIC ZONE ALONG
AND JUST NORTH OF THE NY STATE LINE. QPF/S CONTINUE TO SHOW A
SLIGHT INCREASE FROM PREVIOUS RUNS SO WE MADE SLIGHT ADJUSTMENTS
TO THE SNOWFALL FORECAST TODAY.
H2O VAPOR LOOP REVEALS OUR MAIN INGREDIENT FOR OUR WINTER STORM
WAS MOVING INTO THE TENNESSEE VALLEY. A STRENGTHENING UPPER JET IS
UNDERWAY ACROSS THE SOUTHERN CONUS PER SATELLITE WIND ESTIMATES
AND HOURLY RUC ANALYSIS WITH ANOTHER UPPER JET SEGMENT ACROSS THE
UPPER GREAT LAKES REGION. THIS NORTHERN PORTION OF THE JET IS
EXPECTED TO REMAIN CYCLONIC IN NATURE WHICH SUGGESTS THIS UPPER
LOW MAY TRACK A LITTLE FURTHER WEST AND HANGING ONTO THE INITIAL
SURFACE LOW LONGER BEFORE THE TRANSFER OCCURS OFF THE MID ATLANTIC
COAST. BROAD ISENTROPIC LIFT IN ADVANCE OF THESE FEATURES WAS
UNDERWAY ACROSS THE NY/PA BORDER AS BAROCLINICITY WAS INCREASING
JUST NORTH OF THE ARCTIC BOUNDARY. PER EXPERIMENTAL REFLECTIVITY
FORECASTS FROM A VARIETY OF MESOSCALE MODELS...ALONG WITH THE DRY
AIR IN PLACE...IT MAY TAKE MOST OF THE MORNING TO SATURATE THE
LOWER LEVELS FOR SNOW TO REACH THE GROUND /VIRGA/ NORTH OF I90 AS
LOW LEVEL AGEOSTROPIC FLOW REMAINS IN PLACE /MAGNITUDE IS NOT THAT
STRONG BUT IS VERY PERSISTENT/. USED A BLENDED APPROACH FOR HIGH
TEMPERATURES TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
WINTER STORM WARNING IN EFFECT FOR THE ENTIRE REGION...
AS OF 1230 PM...THE 12Z NAM AND GFS MODEL RUNS TRACK THE LOW FURTHER
NORTH WITH THE TRACK NOW FORECAST TO GO RIGHT OVER LONG ISLAND. THIS
SHOULD RESULT IN ADDITIONAL MID LEVEL WARMING SO HAVE ADJUSTED THE
WEATHER GRIDS TO INCLUDE MORE FREEZING RAIN AND SLEET AFTER 06Z
TONIGHT AND HAVE ALSO PUSHED THE NORTHERN EXTENT OF THE MIXED PCPN
ALL THE WAY INTO THE CENTRAL CATSKILLS...THE SOUTHEAST PART OF THE
CAPITAL DISTRICT...THROUGH ALL OF BERKSHIRE COUNTY AND JUST ACROSS
THE BORDER INTO EXTREME SOUTHERN VERMONT. THIS HAS RESULTED IN ONE
TO FOUR INCH REDUCTIONS IN THE AMOUNTS OF SNOW FORECAST IN THESE
AREAS...WITH THE GREATEST REDUCTIONS OCCURRING OVER LITCHFIELD...
DUTCHESS AND EASTERN ULSTER COUNTIES. IT HAS ALSO EXPANDED THE AREA
WHERE ICING WILL OCCUR. DESPITE THE SNOW REDUCTIONS...STILL ENOUGH
SNOW WITH ENOUGH ICING IS FORECAST TO CONTINUE THE WINTER STORM
WARNINGS IN ALL AREAS...INCLUDING THE SOUTHERN ZONES.
.PREVIOUS DISCUSSION...
PREVIOUS DISCUSSIONS HAVE DONE AN EXCELLENT JOB WITH THE
METEOROLOGICAL PARAMETERS SETTING UP FOR THIS FIRST WIDESPREAD
SIGNIFICANT WINTER EVENT FOR THE REGION. 00Z GUIDANCE ALONG WITH THE
RECENT ARRIVAL OF THE 06Z NAM/GFS CONTINUE TO INCREASE QPF AMOUNTS
ALONG WITH ENHANCED FGEN BANDS SEEN IN THE H850-H700 LAYER PER
PREVIOUS CSTAR RESEARCH. THESE BANDS ARE PROGGED TO BE A LITTLE
FURTHER NORTH AND PER COORDINATION FROM WPC AND SURROUNDING
WFOS...WE WILL UPGRADE THE ADVISORY AREA AND EXTEND THE WARNING
ACROSS THE ENTIRE CWFA. IT WILL BE CLOSE PER THE DEFINITION OF 7"
IN 12HRS OR 9" IN 24HRS BUT WITH A HIGH IMPACT WIDESPREAD EVENT
THE WARNING WAS EXPANDED. AS WARM ADVECTION OCCURS IN THE THERMAL
PROFILES...SOME OF THE PRECIP ACROSS DUTCHESS AND LITCHFIELD
COUNTIES WILL MIX WITH SLEET AND FREEZING RAIN LATE TONIGHT. ICE
ACCUMULATIONS UP TO TWO TENTHS OF AN INCH ARE POSSIBLE BEFORE THE
WARM AIR AT THE SURFACE ARRIVES TO RESULT IN A CHANGEOVER TO
MAINLY RAIN/RAIN SHOWERS LATER SUNDAY MORNING. SO TEMPERATURES
WILL BE STEADY TO SLOWLY RISING OVERNIGHT AS WE WILL SHOW A NON-
DIURNAL TEMPERATURE TREND OVERNIGHT.
THE OTHER COMPLICATED FACTOR TO THIS WILL BE TRANSITIONING
SNOW TO LIQUID RATIOS AS WE SHOULD INITIALLY BE RATHER HIGH WITH
15:1 RATIO THEN GRADUALLY DROPPING TOWARD CLIMATOLOGY OF 12:1 FOR
MOST OF THE REGION AND EVENTUALLY TOWARD 10:1 TOWARD SUNRISE
SUNDAY. THE CROSS SECTIONS NOW REVEAL WE WILL INDEED SEE THE BEST
LIFT OCCUR IN THE BEST DENDRITIC SNOW GROWTH REGION WHICH ALONG
WITH FGEN BANDS TO ENHANCE SNOWFALL RATES. IN FACT...D-THETA/DZ
SUGGESTS THE SMALL POTENTIAL FOR CONVECTIVE ELEMENTS BETWEEN 06Z-
12Z SUNDAY AND AS THE SECONDARY LOW DEVELOPS OFF THE NJ
COAST...THE DUCT FUNCTION POINTS TOWARD THE POTENTIAL FOR A
GRAVITY WAVE/S/.
PRECIP SHADOW IS INDEED STILL PLAUSIBLE TOO AS LOW-MID LEVEL EAST-
SOUTHEAST WINDS INCREASE SUGGESTING PRECIP SHADOW DOWNWIND OF THE
BERKS-TACONICS AND THE GREENS INTO PORTIONS OF WASHINGTON COUNTY.
THIS STORM DEEPENS SUNDAY AS IT TRACKS THROUGH THE SOUTHERN
PORTIONS OF THE GULF OF MAINE WITH DEFORMATION SNOW AXIS ACROSS
PORTIONS OF THE DACKS. WIND GUSTS WILL LIKELY INCREASE TOO WHICH
WILL RESULT IN SOME BLOWING AND DRIFTING OF THE SNOW.
FURTHERMORE...WIND CHILLS WILL LIKELY DIP WELL BELOW ZERO ACROSS
THE DACKS AS WE MAY NEED HEADLINES FOR THIS IN FUTURE FORECASTS.
SNOW WILL TAPER OFF THROUGH THE DAYLIGHT HOURS SUNDAY WITH SOME
LAKE RESPONSE SUNDAY NIGHT INTO PORTIONS OF THE DACKS...WESTERN
MOHAWK VALLEY AND CATSKILLS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
BEHIND THE DEPARTING WINTER STORM...HIGH PRESSURE WILL MOVE OVER
THE REGION FOR MONDAY. WITH A COLD NW FLOW IN PLACE...MAX TEMPS
WILL BE BELOW NORMAL...WITH TEENS TO MID 20S ACROSS THE REGION.
VERY COLD TEMP WILL CONTINUE INTO MONDAY NIGHT WITH SINGLE DIGITS
OVER MUCH OF THE AREA. SOME BELOW ZERO READINGS WILL OCCUR ACROSS
THE ADIRONDACKS AND GREEN MOUNTAINS.
CLOUDS WILL BEGIN TO INCREASE LATE MONDAY NIGHT...WITH A SLIGHT CHC
FOR SOME SNOW SHOWERS...AS A CLIPPER SYSTEM BEGINS TO APPROACH FROM
THE GREAT LAKES. THIS WEAK SYSTEM WILL BE QUITE MOISTURE STARVED.
STILL...THERE IS A CHANCE FOR SOME LIGHT SNOW ACROSS THE REGION FOR
TUESDAY INTO TUESDAY NIGHT AS THIS SYSTEM TRACKS ACROSS THE AREA.
ANY QPF LOOKS RATHER LIGHT...AND SNOWFALL WILL ONLY BE AN INCH OR
TWO FOR MOST PLACES. MAX TEMPS WILL CONTINUE TO BE CHILLY ON TUESDAY
WITH 20S OVER MUCH OF THE AREA...AND TEENS TO LOW 20S FOR TUESDAY
NIGHT.
SOME LAKE EFFECT SNOW WILL OCCUR ACROSS THE WESTERN ADIRONDACKS AND
WESTERN MOHAWK VALLEY BEHIND THIS CLIPPER SYSTEM FOR WED INTO WED
NIGHT. OTHERWISE...IT LOOKS DRY OVER MUCH OF THE AREA. TEMPS ON WED
WILL BE A LITTLE WARMER THAN RECENT DAYS...WITH MID 20S TO MID 30S.
HOWEVER...A REINFORCING SHOT OF COLD AIR LOOKS TO ARRIVE ON WED
NIGHT...WITH TEENS FOR THE AREA...AND TEMPS BACK INTO THE 20S FOR
THURSDAY.
THIS COLD SHOT LOOKS TO BE SHORT LIVED...AS HIGH PRESSURE QUICKLY
PASSES OVER THE AREA...AND THE PATTERN BEGINS TO SHIFT SOMEWHAT.
WHILE IT WILL BE DRY FOR THURSDAY...THE OVERALL FLOW STARTS TO
BECOME MORE OUT OF THE SW BOTH AT THE LOW LEVELS AND ALOFT. THIS
WILL TRANSPORT MUCH WARMER AND MORE MOIST AIR INTO THE REGION FOR
THE LATE WEEK PERIOD. MAX TEMPS LOOK TO REACH INTO THE 40S FOR
VALLEY AREAS BY FRIDAY. ALTHOUGH IT/S STILL RATHER FAR OUT IN
TIME...AN APPROACHING SLOW MOVING FRONTAL BOUNDARY LOOKS TO BRING A
PERIOD OF PLAIN RAIN TO THE REGION FOR LATE IN THE WEEK AND INTO THE
WEEKEND ACROSS THE ENTIRE REGION...EVEN THE HIGHER TERRAIN
AREAS...WITH A RETURN TO ABOVE NORMAL TEMPS EXPECTED INTO THE
WEEKEND.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
A STORM SYSTEM WILL MOVE TOWARDS THE OHIO VALLEY TODAY AND REFORM
OFF THE JERSEY SHORE BY THIS EVENING. AS THIS STORM SYSTEM EVOLVES
AND MOVES TOWARDS THE AREA...LIGHT SNOW WILL CONTINUE TO SLOWLY
SPREAD NORTHWARD. SNOW HAS ALREADY BEGUN AT KPOU...AND SHOULD BEGIN
AT KPSF SOON...KALB BY ABOUT MID MORNING...AND KGFL BY LATE MORNING
OR SO. INITIALLY...THE DRY AIRMASS IN PLACE WILL ONLY ALLOW FOR
LIGHT SNOW AND MVFR CONDITIONS. AFTER ABOUT AN HOUR OR TWO...IFR
SNOW LOOKS FALL WITHIN PERIODS OF LIGHT SNOW. ALTHOUGH AT FIRST THE
SNOW MAY NOT BE STEADY AND FLYING CONDITIONS FLUCTUATE BETWEEN
IFR/MVFR...ALL SITES SHOULD BE SEEING PREDOMINATELY IFR SNOW BY
LATER THIS AFTN AS THE SNOW BEGINS TO BECOME MORE WIDESPREAD. WINDS
TODAY WILL BE N-NE AT AROUND 5 KTS.
AS THE STORM STRENGTHENS RAPIDLY OFF THE COAST...THE SNOW WILL PICK
UP IN INTENSITY BY LATE THIS EVENING AND INTO THE OVERNIGHT HOURS.
AT THIS POINT...LIFR CONDITIONS ARE POSSIBLE AS WELL...WHEN THE SNOW
WILL BE FALLING ITS HARDEST AND VV WILL BE QUITE LIMITED. VSBYS WILL
BE LESS THAN ONE MILE...AND PERHAPS AS LOW AS 1/4SM TO 1/2SM. THE
PRECIP WILL MIX WITH AND CHANGE TO SLEET/FREEZING RAIN AT KPOU AFTER
MIDNIGHT...BUT THE REMAINING SITES WILL STAY ALL SNOW. THE SNOW MAY
START TO DECREASE IN INTENSITY LATE TONIGHT FROM SOUTH TO NORTH AS
THE STORM BEGINS TO MOVE UP TOWARDS NEW ENGLAND...ALTHOUGH FLYING
CONDITIONS WILL REMAIN IFR THROUGH 12Z.
OUTLOOK...
SUN: HIGH OPERATIONAL IMPACT. SN.
SUN NIGHT-MON: LOW OPERATIONAL IMPACT. BREEZY.
MON NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
TUE-TUE NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
WED: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
NO HYDRO RELATED CONCERNS ARE EXPECTED THE NEXT 5 DAYS.
QPF FROM THIS UPCOMING EVENT WILL RANGE FROM ONE HALF INCH TO ONE
AND ONE QUARTER OF AN INCH WITH THOSE HIGHER VALUES ACROSS THE
TERRAIN INTO THE CATSKILLS...SOUTHERN GREENS AND PORTIONS OF THE
DACKS. MOST OF THIS WILL FALL IN THE FORM OF SNOW WITH THE
EXCEPTION ACROSS DUTCHESS AND LITCHFIELD COUNTIES WHERE A WINTRY
MIXTURE AND PERHAPS A PERIOD OF RAIN MAY RESULT LATE SATURDAY
NIGHT INTO SUNDAY MORNING. ANY LIQUID PRECIP SHOULD RESULT WITHIN
BANK RISES.
THEREAFTER...TEMPS WILL CONTINUE TO BE BELOW NORMAL AND ICE WILL
CONTINUE TO FORM AND THICKEN ON AREA RIVERS...STREAMS AND
PARTICULARLY LAKES THROUGH EARLY NEXT WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR CTZ001-013.
NY...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR NYZ032-033-
038>043-047>054-058>061-063>066-082>084.
MA...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR MAZ001-025.
VT...WINTER STORM WARNING UNTIL 1 PM EST SUNDAY FOR VTZ013>015.
&&
$$
SYNOPSIS...GJM/BGM
NEAR TERM...GJM/IAA/BGM
SHORT TERM...GJM/BGM
LONG TERM...FRUGIS
AVIATION...IAA/FRUGIS
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
507 PM EST SAT DEC 14 2013
.SYNOPSIS...
LOW PRESSURE OVER THE MID OHIO VALLEY WILL TRACK ACROSS
PEENSYLVANIA TONIGHT...WITH A SECONDARY LOW DEVELOPING OVER THE DELMARVA
THIS EVENING. THE COASTAL LOW WILL INTENSIFY AS IT MOVES TOWARD
SOUTHERN NEW ENGLAND SUNDAY. AN UPPER TROUGH OF LOW PRESSURE WILL
PERSIST OVER THE MID-ATLANTIC INTO WEDNESDAY.
&&
.NEAR TERM /TONIGHT/...
ADVISORIES AND WRNGS RMN IN EFFECT. NEW PNS HAS BEEN SENT. TOP
SNOWFALL IS ARND 4" AT THE HIGHER WRN ELEVS. SNOW/IP BURST CAME
THRU IAD AT 407 PM AND HAS NOW MOVED UP TO BWI/BALT CITY IN THE
FORM OF RASN. TEMPS IN THE CENTRAL SHEN VLLY IN THE M30S...AND LWX
AND RNK RDR BOTH SHOW RDR REFLECTIVITY BEING SPOTTY FM ROA TO CHO.
FURTHER HRRR SHOWS THE BACK EDGE OF THE PCPN MOVG E OF THE MTNS BY
00Z. WHAT THIS ALL MEANS IS THAT IT IS LKLY THAT SOME OF THE
ADVSRY WL BE DROPPED DURG THE EVE HRS...PSBLY WRNG AS WELL.
LGT RAIN IN THE BALT-WASH METRO AND SOUTH THROUGH THE EVENING.
ALL PRECIP TAPERS OFF THROUGH THE LATE EVENING ACROSS THE
AREA...HOLDING ON THROUGH MIDNIGHT FOR NERN ZONES. MIN TEMPS
GENERALLY LOW TO MID 30S. AREAS WITH SNOW ON THE GROUND SHOULD SEE
SOME ADVECTION FOG TONIGHT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
SUNDAY...POST FRONTAL WLY FLOW BREAKS MORNING FOG/LOW CLOUDS THROUGH
THE MIDDLE MORNING. GUSTS UP TO 30 MPH POSSIBLE BY LATE MORNING.
DOWNSLOPING FLOW ALLOWS FOR MAX TEMPS IN THE UPR 30S TO LOW
40S...MID 30S FOR UP ALONG MASON-DIXON WHERE THE SNOW PACK PERSISTS
AND MID 40S FOR N-CNTRL VA WHERE GREATER DOWNSLOPING OCCURS.
UPSLOPE SNOW THROUGH THE DAY WEST OF THE ALLEGHENY FRONT WITH A
COUPLE INCHES EXPECTED. LATER SHIFTS WILL NEED TO ASSESS WHETHER TO
EXTEND WINTER HEADLINES OR IF IT WILL BE SUB-ADVISORY (3" REQUIRED
FOR ADVISORY).
HIGH PRESSURE WILL BUILD OVER THE MIDDLE ATLANTIC REGION SUNDAY
NIGHT...AND CONTINUE INTO EARLY TUESDAY. GOOD CAA SUN NGT...BUT
DIMINISHES MON. THOSE WL BE THE BREEZY PDS. MON AFTN-NGT SHOULD BE
CALM...AND COLD.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
EXPECTING TEMPS BELOW NORMAL FOR TUESDAY AND WEDNESDAY AS GREAT
LAKES UPPER TROUGH PASSES TO OUR NORTH. VORT MAX AROUND THE BASE
OF THE TROUGH ALONG WITH SOME LIMITED MOISTURE AND COLD FROPA
LOOKS TO BRING SOME UPSLOPE SNOW SHOWERS TO THE ALLEGHENY FRONT
TUESDAY INTO TUESDAY NIGHT. HIGH PRESSURE AND UPPER RIDGING BUILDS
ACROSS THE AREA FOR THURSDAY. A WARMING TREND INTO THE WEEKEND IS
EXPECTED AHEAD OF LONG WAVE TROUGH. SOUTHERN STREAM LOW EJECTING
INTO THE GREAT LAKES REGION FOR NEXT WEEKEND INTO EARLY NEXT WEEK
STILL HAS BIG TIMING AND PLACEMENT INCONSISTENCIES IN LONG TERM
MODELS.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
IFR IN SNOW ONLY REST OF THE AFTERNOON. ACCUMULATING SNOW ONLY IN
KMRB...MAYBE SOME SLUSH AT KBWI...OTW RAIN OR MELTING SNOW AT THE
OTHER TERMINALS. CIGS DROP AND RAIN INCREASES...WITH IFR EXPECTED
ACROSS THE TERMINALS THIS EVENING IN THE EARLY MORNING HOURS. COLD
FRONT CROSSES LATE TONIGHT...BUT IFR CIGS MAY NOT BREAK UNTIL
SUNRISE SUNDAY.
MOSTLY VFR CONDITIONS EXPECTED SUNDAY THROUGH THURSDAY. GUSTY WEST
TO NORTHWEST WINDS EXPECTED SUNDAY AND SUNDAY NIGHT.
&&
.MARINE...
SCA UP FOR ALL WATERS...THOUGH THE ELY FLOW LOOKS TO BE WEAK ON THE
TIDAL POTOMAC...WITH 20 KT GUSTS EXPECTED ON THE MD PORTION OF THE
BAY. THE CENTER OF THE COASTAL LOW WILL TRACK NEAR OR OVER THE MD
PART OF THE BAY...SO THERE WILL PROBABLY BE A LULL IN WINDS UNTIL
MORNING. WLY FLOW GUSTS 20 TO 25 KT ACROSS THE WATERS THROUGH SUNDAY.
BEST MIXING WILL SLIDE EAST OF THE WATERS SUNDAY NIGHT. HV SCA/S
ENDING IN THE PTMC AND WRN INLETS...BUT NOT THE BAY ITSELF OR ERN
INLETS. HIGH PRESSURE BUILDS LATER MON INTO TUE. THAT AFFORDS
ANOTHER OPPORTUNITY FOR DAYTIME MIXING TO REINVIGORATE WNDS MONDAY
MRNG.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER STORM WARNING UNTIL 1 AM EST SUNDAY FOR MDZ003-501-502.
WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR MDZ004>007.
VA...WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR VAZ025>031-
036>040-042-501-503-504.
WV...WINTER STORM WARNING UNTIL 1 AM EST SUNDAY FOR WVZ050>052-
501>504.
WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR WVZ053-055-
505-506.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR ANZ530>534-
539>541-543.
SMALL CRAFT ADVISORY UNTIL 6 PM EST SUNDAY FOR ANZ535-542.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST SUNDAY NIGHT FOR
ANZ536>538.
&&
$$
UPDATE...WOODY!
PRVS...HTS/BAJ/AEB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
134 PM EST SAT DEC 14 2013
.UPDATE...
ISSUED AT 133 PM EST SAT DEC 14 2013
NO CHANGES EXPECT AT THIS TIME TO THE LAKE EFFECT SNOW ADVISORIES
FOR MENOMINEE AND DELTA COUNTIES. AS NOTED IN THE PREVIOUS
DISCUSSION...DOMINANT BANDS HAVE BEEN DIFFICULT TO FORM GIVEN THE
VARYING WINDS AT AND JUST ABOVE THE SFC. DID HAVE REPORT EARLIER
TODAY OF AROUND 1IN OR SNOW IN A LITTLE OVER AN HR OVER FAR SW
SCHOOLCRAFT CO. HAVE ALSO HAD A REPORT OF AROUND 2IN ELSEWHERE IN
THE ADVISORY AREA. RADAR CONTINUES TO HAVE A DIFFICULT TIME PICKING
UP THE BANDING...GIVEN ITS LOWEST SCAN AROUND 7KFT IN THIS AREA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EST SAT DEC 14 2013
WV IMAGERY AND RAP ANALYSIS SHOW A LONG WAVE TROUGH OVER THE
CENTRAL CONUS...WITH MUCH OF THE ENERGY IN THE SOUTHERN STREAM
MOVING THROUGH THE SOUTHERN THIRD OF THE CONUS. CLOSER TO THE UPPER
GREAT LAKES...A SHORTWAVE IS CURRENTLY TRACKING THROUGH SOUTHERN
MANITOBA AND INTO NORTHERN MINNESOTA AT THIS TIME...WITH A BROAD
AREA OF MOISTURE AHEAD OF THIS WAVE IN MN/WI/MI. AT THE SURFACE...A
ELONGATED AREA OF 1034MB HIGH PRESSURE STRETCHES FROM LAKE WINNIPEG
EAST-SOUTHEAST INTO SOUTHWEST QUEBEC...WHILE A TROUGH STRETCHES
NORTHEAST INTO SOUTHERN WISCONSIN FROM A 1007MB LOW IN NORTH
CENTRAL TEXAS. THE FORCING FROM THE SHORTWAVE AND INCREASED
MOISTURE AHEAD OF IT HAS LED TO -SHSN OVER MINNESOTA OVER THE LAST
SEVERAL HOURS AND THEY HAVE EXPANDED EAST INTO WESTERN WISCONSIN.
CLOSER TO THE U.P. 850MB TEMPS OF -17 TO -20C OVER THE CWA HAS
COMBINED WITH LIGHT NORTHEAST TO EASTERLY FLOW TO LEAD TO LIGHT
LAKE EFFECT SNOW SHOWERS OVER SOUTH CENTRAL LAKE SUPERIOR. IT HAS
FINALLY STARTED TO PUSH TO THE NORTHEAST AS THE LOW LEVEL WINDS HAVE
SWITCHED TO THE SOUTH. INVERSION HEIGHTS OF 3-4KFT ON 00Z KINL
SOUNDING AND 08Z KMQT VAD PROFILE ARE LIKELY THE MAIN LIMITING
FACTOR TO THE SNOW OVERNIGHT...IN ADDITION TO THE VARIABLE LOW LEVEL
FLOW. FARTHER SOUTH...LAKE ENHANCED SNOWFALL CONTINUES OFF
LAKE MICHIGAN IN EAST CENTRAL AND PARTS OF NORTHEAST WISCONSIN.
THERE WAS A STRONGER BAND AFFECTING OCONTO EARLIER IN THE
NIGHT...BUT IT HAS SINCE WEAKENED. THERE ARE SOME HINTS THAT THE
LAKE EFFECT IS NEARING MENOMINEE...BUT VISIBILITIES THERE ARE STILL
10SM.
MUCH OF THE FORECAST FOR THE SHORT TERM WILL FOCUS ON THE SHORTWAVE
AND LAKE EFFECT/ENHANCED SNOWFALL UNDER VEERING LOW LEVEL WINDS TO
THE SOUTHEAST THROUGH THE EVENING. AS THE SHORTWAVE SHIFTS INTO
WISCONSIN AND UPPER MICHIGAN THIS AFTERNOON...A INVERTED TROUGH WILL
DEVELOP NORTHWEST FROM THE LOW MOVING INTO THE MID ATLANTIC STATES.
00Z KINL SOUNDING FAIRLY REPRESENTATIVE OF THE LIMITED MOISTURE IN
LOWER LEVELS ROTATING AROUND THE HIGH (VERY DRY BETWEEN
940-700MB)...BUT EXPECT THAT TO GIVEWAY FROM SOUTHWEST TO NORTHEAST
LATE THIS MORNING AND CONTINUE INTO THE AFTERNOON. ALREADY FAIRLY
MOIST ON THE 00Z KGRB SOUNDING AND WITH THAT CLOSE PROXIMITY AND
LIGHT NORTHEASTERLY PUSH AROUND THE HIGH...THE DRIER AIR SHOULD GIVE
AWAY FAIRLY EASILY. FORCING FROM THE SHORTWAVE AND INVERTED TROUGH
WILL DEVELOP LIGHT SNOW ACROSS MUCH OF THE AREA LATE THIS MORNING
BEFORE DIMINISHING FROM WEST TO EAST THROUGH THE LATE AFTERNOON AND
EVENING HOURS. FOCUS TURNS TO LAKE EFFECT/ENHANCED SNOWFALL.
FIRST...THE SNOW OVER SOUTH CENTRAL LAKE SUPERIOR SHOULD CONTINUE
TO DRIFT NORTHWEST THIS MORNING AND BRIEFLY CROSS THE KEWEENAW
PENINSULA BEFORE MOVING BACK INTO LAKE SUPERIOR. THE MAIN AREA OF
CONCERN IS FOR LAKE ENHANCED SNOWFALL ALONG THE BAY OF GREEN BAY.
INDICATIONS ARE THERE FROM THE MODELS AND THE DELTA-T VALUES
OF 18 TO 21 SUPPORT IT...BUT HIGHER RESOLUTION MODELS WHICH
TRADITIONALLY OVER DO QPF ARE STRUGGLING TO PUT OUT ANY SIGNIFICANT
VALUES OVER SOUTHERN MENOMINEE AND SOUTHEAST DELTA COUNTIES TODAY.
HAVE A FEELING THAT THE STRUGGLE TO PUT OUT ANY DECENT QPF IS
RELATED TO THE LOW LEVEL SHEAR INDICATED BY THE MODELS. THIS CAN BE
SEEN AT THE PRESENT TIME IN EAST CENTRAL WISCONSIN WHERE WINDS ARE
PREDOMINATELY EASTERLY IN THE LOWER LEVELS AND LAKE ENHANCEMENT IS
OCCURRING. BUT FARTHER NORTH ACROSS THE BAY OF GREEN BAY...THE DRIER
AIR COMBINED WITH WINDS VARYING IN DIRECTION DEPENDING ON LEVEL
(850MB VEERING SOUTHEAST...925MB STAYING MAINLY EASTERLY...AND
SURFACE WINDS NORTHEASTERLY) HAS BEEN LIMITING DEVELOPMENT THUS
FAR. THIS WILL LIKELY CONTINUE THROUGH THE AFTERNOON UNTIL THE
TROUGH DEVELOPS ACROSS THE AREA AND FOCUSES WINDS OUT OF THE
SOUTHEASTERLY DIRECTION THIS EVENING. AM WONDERING IF THIS SHEAR
WILL BE ENOUGH TO LIMIT ANY REAL STRONG LAKE ENHANCED BANDS. IN
ADDITION...INVERSION HEIGHTS AROUND MENOMINEE THIS MORNING ARE
AROUND 5-6KFT AND REMAINS THROUGH MUCH OF TODAY...LIKELY LIMITING
STRONG ENHANCEMENT AND HIGHER TOTALS. THEY ARE A LITTLE HIGHER
AROUND ESCANABA (6-7KFT THIS AFTERNOON/EVENING) AND WHEN COMBINED
WITH THE MORE UNIFORM FLOW THIS EVENING...THINK THAT IS WHEN THEY
WILL HAVE THE BEST OPPORTUNITY FOR MODERATE SNOWFALL. ON THE
POSITIVE SIDE...MUCH OF THE LAKE ENHANCED FORCING IS IN OR JUST
BELOW THE DGZ AND ALLOW FOR SNOW RATIOS TO BE HIGHER AND AROUND 20
TO 1. UNFORTUNATELY...DEALING WITH AROUND 20-1 SNOW RATIOS MAKES FOR
A DIFFICULT TIME ON PINNING DOWN AMOUNTS ON THESE LOWER END QPF
AMOUNTS. MODEL COBB SNOW AMOUNTS ARE ALL OVER THE BOARD WITH 12Z NAM
FOR KESC GIVING AROUND 3.5-4IN AND OUR LOCAL 00Z WRF-ARW HAS
3-3.8IN...WHILE THE 08Z RAP IS GIVING 1.3IN THROUGH 02Z. 03Z SREF
MEAN HAS 2.3-3.0 AND THINK THAT IS A REASONABLE COMPROMISE. AMOUNTS
FOR KMNM HAVE A SIMILAR RANGE...WITH THE HIGHEST AMOUNTS FROM THE
MODELS OF 4-5INCHES...BUT THOSE RUNS HAD 2IN OF ACCUMULATION ALREADY
EVEN THOUGH IT HASN/T EVEN STARTED SNOWING. THEREFORE...OPTED TO
LOWER AMOUNTS ABOUT AN INCH AND MAY NEED TO DO MORE IF THE SNOW
STRUGGLES TO DEVELOP THIS MORNING. STILL THINK THE HIGHEST AMOUNTS
WILL BE OVER THE GARDEN PENINSULA...WHERE AMOUNTS COULD REACH 5
INCHES.
OVERALL VERY UNCERTAIN ON SNOWFALL AMOUNTS FOR MENOMINEE AND DELTA
COUNTIES TODAY...LARGELY DUE TO THE LOW LEVEL SHEAR THAT LOOKS LIKE
IT WILL OCCUR. A LITTLE MORE CONFIDENCE IN PORTIONS OF DELTA AS
WINDS BECOME MORE FAVORABLE THIS EVENING AND THERE IS LESS
SHEAR...BUT EVEN THEN THE BANDS WILL LIKELY BE MOVING ENOUGH TO THE
EAST TO LIMIT SIGNIFICANT ACCUMULATIONS. THEREFORE...WILL KEEP THE
ADVISORY GOING FOR NOW (WITH WEAKER WORDING AND GREATER RANGE IN
TOTALS TO SHOW UNCERTAINTY) SINCE THEY SHOULD SEE SOME SNOW AND
ALLOW THE DAY SHIFT TO ASSESS THE SITUATION THROUGH THE MORNING.
WITH THE UNCERTAINTY...DID NOT EXPAND ADVISORY TO SOUTHERN
SCHOOLCRAFT FOR TONIGHT EVEN THOUGH THERE TOTALS ARE IN THE SAME
RANGE AS SOUTHERN DELTA COUNTY.
A SURFACE LOW LOOKS TO DEVELOP ALONG THE SURFACE TROUGH OVER
NORTHERN LAKE SUPERIOR TONIGHT AS A SECONDARY AND STRONGER
SHORTWAVE DROPS OVER LAKE SUPERIOR. THE FLOW AROUND THE LOW WILL
KEEP MUCH OF THE LAKE EFFECT AWAY FROM THE LAKE SUPERIOR SHORELINES
THIS EVENING...BEFORE WINDS SHIFT TO THE WEST-NORTHWEST OVER THE
WESTERN LAKE OVERNIGHT WITH THE LOW MOVING INTO THE EASTERN LAKE.
THEREFORE...SHOULD SEE LAKE EFFECT INCREASING OVER THE WESTERN HALF
OF THE CWA OVERNIGHT WITH THAT WINDSHIFT AND THE INTENSIFYING LOW
OVER THE NORTHERN/EASTERN LAKE. INVERSION HEIGHTS DO LOOK TO IMPROVE
TO AROUND 10KFT OVER THE WESTERN LAKE OVERNIGHT AND WITH THE HELP OF
THE ADDITIONAL MOISTENING TODAY FROM THE SURFACE TROUGH...THAT AREA
SHOULD BE ABLE TO REALIZE THOSE FAIRLY HIGH INVERSION HEIGHTS.
850MB TEMPS FALL FROM -16C AT 06Z TO -20C BY 12Z SUNDAY...SO LAKE
INSTABILITY IS PRESENT AND BUFKIT SOUNDINGS ARE SHOWING LAKE INDUCED
CAPES IN THE 400-600 J/KG RANGE. IN ADDITION...THE EXTRA
FORCING FROM THE SHORTWAVE (INCREASING MID LEVEL Q-VECTOR
CONVERGENCE) WILL PRODUCE A CONDUCIVE PERIOD FOR LAKE EFFECT
SNOWFALL. THUS...WOULD EXPECT THERE TO BE A FAIRLY DECENT BURST OF
SNOW AFTER ABOUT 06Z FROM THE PORKIES UP THROUGH THE KEWEENAW
PENINSULA AS THE WINDS SHIFT TO THE WNW. HIGH RESOLUTION MODELS
AGREE FAIRLY WELL WITH THIS TIMING AND WILL BUMP POPS UP TO 100
PERCENT IN THOSE AREAS OVERNIGHT. WITH MUCH OF THE FORCING RIGHT
WITHIN AND A LITTLE ABOVE THE DGZ...SHOULD SEE FAIRLY DECENT SNOW
RATIOS (AROUND 20-22 TO 1) AND WOULD EXPECT AT LEAST OF COUPLE HOUR
PERIOD OF 1 IN/HR SNOWFALL AFTER 06Z IN SOME LOCATIONS.
THEREFORE...HAVE TRENDED THE SNOWFALL FORECAST UP A LITTLE BIT WITH
A GENERAL 1-3 INCH AMOUNTS AND HAVE THE HIGHEST VALUES OVER THE
HIGHER TERRAIN FROM THE PORKIES THROUGH THE KEWEENAW.
OVER THE REST OF THE CWA...WINDS WILL BE SHIFTING FROM
SOUTH-SOUTHEAST TO WESTERLY AS THE LOW MOVES TO THE EAST THROUGH
THE NIGHT. EXPECT THE ONGOING LAKE EFFECT OFF LAKE MICHIGAN TO
FOLLOW THAT EASTWARD PUSH THROUGH THE NIGHT AND LARGELY INFLUENCING
DELTA COUNTY IN THE EVENING AND THEN SCHOOLCRAFT AND SOUTHERN LUCE
COUNTIES DURING THE OVERNIGHT HOURS. THE EXPECTED EASTWARD MOVEMENT
OF THE LAKE ENHANCED SNOWFALL SHOULD LIMIT THE SNOWFALL AMOUNTS OVER
MOST OF THOSE AREAS TO A QUICK 1-3IN OF SNOW TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 403 AM EST SAT DEC 14 2013
NAM SHOWS A CLOSED 500 MB LOW NORTH OF LAKE SUPERIOR 12Z SUN WHICH
MOVES SOUTHEAST ON SUN. ANOTHER UPPER TROUGH DIGS SOUTHEAST INTO THE
AREA FOR MON NIGHT. NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE
12Z MON MOVING INTO THE AREA WITH SOME DEEPER MOISTURE WHICH REMAINS
INTO MON NIGHT. LAKE EFFECT SNOW WILL CONTINUE THIS PERIOD FOR
SUNDAY INTO SUNDAY EVENING WITH COLD AIR IN NORTHWEST AND NORTH LAKE
EFFECT SNOW BELTS. ON MONDAY...THERE COULD BE SOME LAKE ENHANCEMENT
MON AFTERNOON AND EVENING OFF OF LAKE MICHIGAN AND HAVE THIS COVERED
WITH LIKELY POPS IN THE EASTERN CWA FOR SOUTHWEST WIND FLOW. HAVE
LIKELY POPS MON NIGHT ACROSS THE KEWEENAW FOR WEST FLOW LAKE EFFECT
SNOW BELTS. DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR
TEMPERATURES.
IN THE EXTENDED...GFS AND ECMWF SHOW A BROAD 500 MB TROUGH OVER THE
CENTRAL AND EASTERN U.S. 12Z TUE. THIS TROUGH PULLS EAST 12Z WED
WITH SFC HIGH PRESSURE ALONG THE MISSISSIPPI RIVER VALLEY. SFC LOW
PRESSURE MOVES INTO THE CENTRAL PLAINS 12Z THU. GFS AND ECMWF SHOW A
500 MB TROUGH OVER THE NORTHERN PLAINS AND DESERT SW 12Z FRI. COLDER
THAN NORMAL TEMPERATURES LOOK TO CONTINUE THIS FORECAST PERIOD
EXCEPT FOR A BRIEF RESPITE ON THU INTO FRIDAY BEFORE COLD AIR
ARRIVES AGAIN. STILL LOOKS COLD ENOUGH WITH A WARM FRONT TO THE
SOUTH AND WARM AIR JUST TO THE SOUTH TO KEEP THE PCPN AS SNOW ON
THU...BUT WILL HAVE TO WATCH THIS AS THERE IS A LOW POSSIBILITY OF
SOME MIXED PCPN IN THE FAR SOUTH. BASICALLY...LAKE EFFECT SNOW WILL
CONTINUE THROUGH WED BEFORE SYSTEM KICKS OUT ON THU. COLD AIR THEN
ARRIVES AGAIN LATE ON FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 133 PM EST SAT DEC 14 2013
CEILINGS CONTINUE TO FLUCTUATE BETWEEN VFR AND MVFR...WITH SMALL
SNOWFLAKES RESULTING IN VIS RESTRICTIONS OF IFR BACK UP THROUGH VFR.
A SFC LOW OVER N AND W LAKE SUPERIOR WILL SLIDE ACROSS THE W
COUNTIES OF UPPER MI...INCLUDING THE IWD AND CMX TAF SITES BETWEEN
05-09Z SUNDAY. BEHIND THE EXITING LOW...A POCKET OF COLDER AIR ALOFT
ACCOMPANIED BY ONSHORE/UPSLOPE WINDS OFF LAKE SUPERIOR WILL RESULT
IN THE BEST CHANCE OF ACCUMULATING SNOW AND WORST FLYING CONDITIONS
SUNDAY FROM APPROX 10-18Z...WITH A SLOW IMPROVEMENT SUNDAY AFTERNOON
AS WINDS DIMINISH AND BECOME MORE NORTHERLY. THE NW WINDS WILL TAKE
OVER AT SAW BEHIND THE SFC LOW AROUND 12Z SUNDAY. WITH LESS THAN
FAVORABLE WINDS...WILL EXPECT VFR TO HIGH END MVFR CEILINGS/VIS
BEHIND THE LOW AND ITS ASSOCIATED TROUGH.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EST SAT DEC 14 2013
HIGH PRESSURE OVER SOUTHERN ONTARIO EARLY THIS MORNING WILL MOVE
EAST INTO SOUTHWEST QUEBEC TODAY WHILE A LOW PRESSURE SYSTEM TAKING
SHAPE IN THE LOWER MISSISSIPPI VALLEY MOVES INTO THE MID ATLANTIC
STATES. WHILE THIS OCCURS...A LOW PRESSURE TROUGH WILL SETUP OVER
THE UPPER GREAT LAKES THIS AFTERNOON AND THEN DEVELOP INTO A WEAK
LOW TONIGHT BEFORE SHIFTING SOUTHEAST SUNDAY AFTERNOON INTO SUNDAY
NIGHT. EXPECT GENERALLY LIGHT WINDS ALONG THIS TROUGH TODAY AND
TONIGHT...BUT DO EXPECT THEM TO INCREASE OUT OF THE NORTHWEST ON
SUNDAY...WITH GUSTS TO 30KTS EXPECTED SUNDAY AFTERNOON/EVENING.
WINDS WILL QUICKLY DIMINISH LATE SUNDAY NIGHT BEFORE INCREASING OUT
OF THE SOUTHWEST ON MONDAY (GUSTS TO 30KTS) AHEAD OF A CLIPPER LIKE
LOW MOVING SOUTHEAST THROUGH SOUTHERN CANADA AND BRUSHING THE UPPER
GREAT LAKES ON MONDAY NIGHT AND TUESDAY. AS THE COLD FRONT SWEEPS
THROUGH ON MONDAY NIGHT...EXPECT WINDS TO SHIFT TO THE NORTHWEST
AND BE IN THE 20-30KT RANGE. THERE COULD EVEN BE SOME GALE FORCE
GUSTS TO 35KTS TUESDAY INTO TUESDAY NIGHT. ANOTHER QUICK HIGH
PRESSURE RIDGE WILL MOVE IN ON WEDNESDAY AND DIMINISH WINDS AHEAD
OF LOW DEVELOPING IN THE CENTRAL PLAINS AND EXPECTED TO MOVE
THROUGH THE GREAT LAKES REGION ON THURSDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST SUNDAY FOR MIZ013.
LAKE EFFECT SNOW ADVISORY UNTIL 8 PM CST THIS EVENING FOR MIZ012.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KF
SHORT TERM...SRF
LONG TERM...07
AVIATION...KF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
338 PM CST SAT DEC 14 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 338 PM CST SAT DEC 14 2013
LIGHT SNOW CONTINUED ACROSS THE REGION TODAY AHEAD OF A WEAK
SHORTWAVE THAT WAS EMBEDDED IN THE PERSISTENT NORTHWEST FLOW.
FORECAST SOUNDINGS OFF THE RAP SHOWED A BEAUTIFUL VEERING
PROFILE...WITH DENDRITIC SATURATION FROM THE SURFACE UP TO 650MB.
THE REGION OF ASCENT ROOTED IN THE POSITIVE VORTICITY ADVECTION
ASSOCIATED WITH THE CURVATURE OF THIS WAVE WILL CONTINUE TO SHIFT
EASTWARD OVERNIGHT. MODEST H500 HEIGHT RISES AND AN ASSOCIATED
SURFACE RIDGE OF HIGH PRESSURE WILL BUILD OVER WESTERN MN...WHICH
WILL SET THE STAGE FOR ANOTHER NIGHT OF COLD TEMPERATURES WITH LIGHT
WINDS...ESPECIALLY IF SKIES MANAGE TO CLEAR. HOWEVER...DESPITE THE
SURFACE HIGH...CONFIDENCE IN CLEARING SKIES IS LOW AS AGITATED
NORTHWEST FLOW WILL CONTINUE. THE THERMAL PROFILE FROM FORECAST
SOUNDINGS ARE SUCH THAT ONLY A SMALL AMOUNT OF UPWARD VERTICAL
MOTION IS REQUIRED TO PRODUCE A FEW SNOWFLAKES...LET ALONE MID LEVEL
CLOUDS. IN FACT...THE NEXT UPPER LEVEL WAVE / LOW LEVEL WARM AIR
ADVECTION DUO WILL MOVE ACROSS WESTERN MN ON SUNDAY...SO HAVE
INCREASED POPS CONSIDERABLY SINCE CONFIDENCE IS HIGH IN ANOTHER
ROUND OF LIGHT SNOWFALL ALONG THE MINNESOTA RIVER VALLEY. SUNDAYS
HIGH TEMPERATURES WILL STRUGGLE TO GET OUT OF THE SINGLE DIGITS FOR
MOST LOCATIONS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 338 PM CST SAT DEC 14 2013
THE UPPER WAVE BRINGING LIGHT SNOW SUNDAY WILL SLIDE SOUTHEAST
INTO THE OHIO VALLEY SUNDAY NIGHT WHILE ANOTHER WAVE DIVES
SOUTHEAST INTO NORTHERN MINNESOTA EARLY MONDAY MORNING. A QUICK
SHOT OF DECENT ISENTROPIC UPGLIDE AND MODEST MOISTURE ADVECTION
WILL BE ENOUGH TO GENERATE A BAND OF SNOW ACROSS NORTHERN AND
CENTRAL MN WHICH WILL PROPAGATE INTO WESTERN WISCONSIN MONDAY
MORNING. ONE TO TWO INCHES OF SNOW ARE POSSIBLE BEFORE STRONG
ISENTROPIC DOWNGLIDE TAKES OVER AGAIN IN THE AFTERNOON AND MONDAY
NIGHT.
A TROUGH DIGGING INTO THE GREAT LAKES WILL CLIP THE FORECAST
AREA...LEAVING WESTERLY SURFACE FLOW IN PLACE THROUGH MIDWEEK.
MILD TEMPS /COMPARED TO THE REST OF THIS MONTH/ CAN BE
EXPECTED...ALTHOUGH TUESDAY NIGHT WILL BE COLD AS THE RIDGE
AXIS PASSES OVERHEAD.
EYES THEN TURN TO LATE WEEK AS A TROUGH DIGS DOWN THE WEST COAST
AND HIGH PRESSURE BUILDS SOUTHWARD INTO WESTERN AND CENTRAL
CANADA. FAST ZONAL FLOW WILL DEVELOP ALONG THE U.S./CANADIAN
BORDER WEDNESDAY WITH ONE WAVE RAPIDLY PUSHING EAST ACROSS
NORTHERN MINNESOTA. SENSIBLE WEATHER IMPACTS FOR OUR AREA WILL BE
MINIMAL INITIALLY WITH FORCING AND MOISTURE CONVERGENCE REMAINING
WELL NORTH. HOWEVER...THIS WAVE AND HIGH PRESSURE BUILDING TOWARD
THE NORTHERN PLAINS WILL PUSH A COLD FRONT SOUTH WEDNESDAY NIGHT.
AS SOME ENERGY ROUNDS THE BASE OF THE WESTERN TROUGH...A SURFACE
LOW WILL SPAWN OVER COLORADO THURSDAY AND TRACK EAST NORTHEAST
ACROSS THE PLAINS AND INTO THE LOWER GREAT LAKES LATE
THURSDAY/THURSDAY NIGHT. NORMALLY THIS WOULD BE A HIGHLY FAVORABLE
TRACK FOR HEAVY SNOWFALL ACROSS THE CWA. HOWEVER...GIVEN THE FAST
FLOW WITH TIGHTENING BAROCLINICITY LEADING TO A MORE PROGRESSIVE
FEATURE...IN CONJUNCTION WITH SURFACE RIDGING OVER THE GULF WHICH
WILL LIKELY DELAY THE NORTHERLY MOISTURE TRANSPORT UNTIL THE
SURFACE WAVE IS TO THE EAST OF THE AREA...WOULD LIMIT THE
POTENTIAL FOR A BIG SNOWFALL. IF MODELS EVOLVE THE WESTERN TROUGH
DIFFERENTLY...AND THEY MOST LIKELY WILL AT THIS RANGE...THIS
FORECAST CAN CERTAINLY CHANGE. LEFT POPS IN THE MID RANGE FOR NOW
WITH THE MOISTURE UNCERTAINTY AND SOME TIMING DIFFERENCES BETWEEN
THE MEDIUM RANGE MODELS.
THE HIGH WILL BUILD IN FOR FRIDAY AND SATURDAY WITH ANOTHER BLAST
OF ARCTIC AIR ACCOMPANYING IT. HIGHS WILL AGAIN BE IN THE SINGLE
DIGITS WITH LOWS FRIDAY NIGHT IN THE TEENS TO 20S BELOW ZERO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1129 AM CST SAT DEC 14 2013
LIGHT SNOW WILL CONTINUE EASTWARD INTO WISCONSIN...WITH A FEW
FLURRIES LAGGING BEHIND. LIGHT WINDS WILL GRADUALLY BECOME
NORTHWESTERLY. CEILINGS REMAIN THE BIGGEST CHALLENGE...AND AFTER A
FEW BREAKS THIS AFTERNOON SHOULD SEE MVFR CLOUDS RETURN LATER
TONIGHT ACROSS THE NORTHERN SITES. TOMORROW LIGHT SNOW WILL
DEVELOP IN WESTERN MN AFFECTING KAXN AND KRWF.
KMSP...
VFR CONDITIONS SHOULD HOLD MOST OF THE AFTERNOON. A FEW BRIEF
REDUCTION IN VISBYS ARE POSSIBLE WITH LINGERING LIGHT SNOW
SHOWERS. CONFIDENCE IS LOW IN THE MVFR CEILING FORECAST FOR THIS
EVENING. TOMORROWS SNOW SHOULD BE WEST AND SOUTH OF THE
METRO...WITH ONLY MID LEVEL CLOUDS EXPECTED AT KMSP.
/OUTLOOK FOR KMSP/
MON...VFR/MVFR WITH IFR/-SN POSSIBLE. WINDS SW AT 10KTS.
TUE...VFR WITH MVFR/-SN POSSIBLE. WINDS W AT 10KTS.
WED...VFR. WINDS VRBL AT 05KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...BORGHOFF
AVIATION...JRB
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1200 PM CST SAT DEC 14 2013
.UPDATE...
ISSUED AT 1155 AM CST SAT DEC 14 2013
UPDATED FOR AVIATION DISCUSSION.
UPDATE ISSUED AT 1017 AM CST SAT DEC 14 2013
LIGHT SNOW WAS FALLING ACROSS MOST OF THE NORTHLAND THIS
MORNING...WITH BANDS OF HEAVIER SNOWFALL OCCURRING FROM THE TWIN
PORTS NORTH ALONG THE NORTH SHORE. SPOTTERS AROUND LUTSEN AND
TOFTE HAVE HAD 3-4 INCHES SO FAR...WITH RATES OF 1 TO 1.5 INCHES
PER HOUR AT LUTSEN. CONDITIONS LOOK VERY FAVORABLE FOR PERIODS OF
HEAVIER SNOW BANDS FROM SILVER BAY THROUGH AT LEAST GRAND
MARAIS...SHIFTING AWAY FROM SILVER BAY EARLIER THIS AFTERNOON. WE
UPGRADED THE ADVISORY FOR COASTAL LAKE AND COOK COUNTIES TO A
WARNING WITH ADDITIONAL SNOWFALL OF 4 TO 7 INCHES...MAINLY BETWEEN
SILVER BAY AND GRAND MARAIS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CST SAT DEC 14 2013
HAS BEEN QUITE A NIGHT IN TERMS OF LAKE EFFECT SNOW. RECEIVED A
REPORT A SHORT TIME AGO OF CLOSE TO A FOOT OF SNOW FROM A VERY
SMALL LAKE EFFECT SNOW BAND THAT PARKED OVER THE CITY OF SUPERIOR
FRIDAY EVENING. AFTER BEING IN ONE LOCATION FOR SEVERAL HOURS...IT
HAD BASICALLY STARTED ITS PROGRESSION ALONG THE NORTH SHORE BY
MIDNIGHT. THE HEAVIEST SNOW BAND WAS JUST NORTHEAST OF GOOSEBERRY
FALLS STATE PARK AS OF 4 AM. THE HIGH RESOLUTION MODELS ARE
GENERALLY IN AGREEMENT THAT THE BANDS WILL CONTINUE TO MEANDER
ACROSS THE NORTH SHORE OF LAKE SUPERIOR TODAY. THE HRRR SEEMS TO
HAVE A FAIRLY DECENT HANDLE ON THE CURRENT LOCATION OF THE
HEAVIEST SNOW BAND...WITH LOCALLY HEAVY SNOW ACROSS LAKE COUNTY
THROUGH THE MORNING. THE HRRR AND MOST OF THE OTHER MODELS THEN
MIGRATE THAT AREA OF HEAVIER SNOW INTO COOK COUNTY FOR THE
AFTERNOON. GOING TO CONTINUE THE LAKE EFFECT SNOW ADVISORY...WITH
LOCALIZED 5 TO 7 INCHES...BUT COULD POTENTIALLY SEE MORE THAN THAT
IF THE BANDS PARK OVER ONE LOCATION FOR TOO LONG. WILL HAVE TO
KEEP A CLOSE EYE ON IT TODAY.
MEANWHILE...LIGHT SNOW WILL PROGRESS ACROSS MUCH OF THE NORTHLAND
TODAY. AMOUNTS WILL GENERALLY BE LIGHT WITH 1 TO 2 INCHES FOR MOST
AREAS.
ARCTIC HIGH PRESSURE WILL THEN BUILD DOWN BEHIND THE DEPARTING
WEAK LOW PRESSURE SYSTEM TONIGHT. HAVE DROPPED TEMPS
CONSIDERABLY...ESPECIALLY ACROSS THE NORTH. COULD SEE SOME -20S
ESPECIALLY ACROSS THE NORTH.
HAVE ALSO DROPPED TEMPS A BIT FOR SUNDAY...AS IT APPEARS SOME
NORTHERN LOCATIONS MAY STRUGGLE TO REACH ZERO DESPITE PARTIAL
SUNSHINE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 415 AM CST SAT DEC 14 2013
FAST MOVING SHORTWAVE WILL MOVE ACROSS THE CWA EARLY IN THE PERIOD
WITH A PERIOD OF LIGHT SNOW OCCURRING LATE SUNDAY NIGHT INTO EARLY
TUESDAY. BEYOND THAT THE UPPER JET WILL STRETCH ACROSS THE REGION
THROUGH EARLY THURSDAY. WITHIN THAT TIME PASSING SNOW SHOWERS ARE
POSSIBLE...MAINLY OVER THE NRN AND ERN CWA. ALL MED RANGE MDLS
SUPPORT THE MOVEMENT OF ANOTHER MID LVL TROF OVER THE REGION
THUR/FRI. POPS INCREASE LATE IN THE WEEK HOWEVER DOMINANT NRN BRANCH
OF UPPER JET WILL KEEP ANY SIGNIFICANT SFC DEVELOPMENT SOUTH AND
EAST OF THE AREA. TEMPS WILL MODERATE TO SOME EXTENT DURING THE EARLY
WEEK ESPECIALLY OVER THE SOUTH AND WEST AS FAST FLOW ALOFT KEEPS ANY
REINFORCING ARCTIC AIR FOCUSED JUST NORTH OF THE REGION ACROSS SRN
CANADA. LATE IN THE WEEK A DEVELOPING SFC LOW WILL MOVE FROM THE
PLAINS INTO THE LOWER GT LAKES. THIS SYSTEM WILL PULL ANOTHER SURGE
OF COLDER AIR SOUTH FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1155 AM CST SAT DEC 14 2013
VARIABLE CIGS THIS AFTERNOON AND THIS EVENING WITH IMPROVING VSBYS
IN LIGHT TO MDT SNOW SHOWERS. CIGS SHOULD BECOME DOMINANTLY MVFR
THIS EVENING AND TONIGHT...WITH LOW CLOUDS BREAKING UP SUNDAY
MORNING. LIGHT SW WINDS WILL SHIFT TO THE NW TONIGHT AND GUST 10
TO 20 KT IN THE LATE EVENING AND OVERNIGHT HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 11 -11 1 -7 / 100 30 10 30
INL 3 -21 -3 -10 / 100 10 10 40
BRD 11 -13 3 -4 / 100 10 10 40
HYR 17 -8 4 -9 / 100 30 10 20
ASX 17 -1 8 -4 / 90 50 30 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...LAKE EFFECT SNOW ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ012.
LAKE EFFECT SNOW WARNING UNTIL 6 PM CST THIS EVENING FOR MNZ020-
021.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM...CANNON
AVIATION...BJT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1140 AM CST SAT DEC 14 2013
.UPDATED FOR 18Z AVIATION DISCUSSION...
ISSUED AT 1129 AM CST SAT DEC 14 2013
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM CST SAT DEC 14 2013
YET ANOTHER PROLONGED LIGHT SNOW EVENT IS ONGOING ACROSS THE AREA
THIS MORNING. FORCING FOR THIS IS RATHER WEAK AND BEST EVIDENCE
OF THIS IS PROBABLY THE FACT THAT A QUICK WALK OUTSIDE AT 230 AM
THIS MORNING REVEALED THAT THE MOON WAS STILL VISIBLE THROUGH ALL
THE SNOW AND CLOUDS! THE UPPER WAVE RESPONSIBLE FOR THE SNOW SHOWS
UP WELL WITH A PLOT OF POTENTIAL VORT OFF THE RAP AT H4 WHICH HAS
SHOWN A WEAK ANOMALY STEADILY PUSHING EAST ACROSS THE DAKOTAS THIS
MORNING. THIS PV FEATURE AS ALSO BEEN AIDED BY WEAK DIFFLUENCE
ALOFT WITHIN THE RIGHT ENTRANCE OF AN UPPER JET THE STRETCHES FROM
CENTRAL MN OVER TO NEW ENGLAND. SNOW REPORTS FALL OFF QUICKLY WEST
OF THE PV FEATURE OVER THE DAKOTAS...AND EXPECT THIS TREND TO
CONTINUE AS THIS WAVE WORKS ACROSS THE AREA TODAY. HRRR TIMING FOR
WORKING THE BACK EDGE OF THE SNOW ACROSS THE AREA MATCHES UP
FAIRLY WELL WITH THE RAPS TIMING OF THE PV FEATURE ACROSS THE
AREA...SO LET THE HRRR REFLECTIVITY FORECAST GUIDE POPS FOR TODAY.
THIS RESULTED IN A SLIGHT SLOWING OF THE POP DECREASE FROM WEST TO
EAST THAT WILL START AROUND 12Z OUT BY THE SODAK BORDER. THIS
SYSTEM WILL QUICKLY MOVE OUT OF THE EASTERN CWA THIS
EVENING...WITH TONIGHT EXPECTED TO BE MAINLY SNOW FREE. THE ONLY
POTENTIAL EXCEPTION TO THIS WILL BE LATE TONIGHT OUT IN FAR
WESTERN MN AS NEXT SHIELD OF WAA PRECIP WILL BE MOVING ACROSS THE
DAKOTAS...THOUGH BETTER PRECIP CHANCES WITH THIS LOOK TO ARRIVE
SUNDAY MORNING.
FOR CURRENT SNOW...CONTINUED TREND OF FAIRLY WIDESPREAD 1-2 INCHES
OF SNOW ACROSS THE ENTIRE AREA. ALL MODELS FROM THE HRRR AND
HOPWRF TO THE ECMWF/GFS SHOW FAIRLY WIDESPREAD TOTAL QPF AMOUNTS
BETWEEN 0.05 AND 0.10 INCHES...WHICH SHOULD BE ABLE TO TRANSLATE
INTO THE 1-2 INCH RANGE. THOUGH BUFKIT THERMAL PROFILES WITH THEIR
DEEP DENDRITIC GROWTH ZONES WOULD SUGGEST SEEING SNOW RATIOS IN
EXCESS OF 20:1...WEAK NATURE OF FORCING HAS PREVENTED ICE CRYSTAL
GROWTH FROM GETTING OUT OF HAND...KEEPING SNOW TYPE AS MAINLY FINE
CRYSTALS. HENCE WHY 12-15 HOURS OF LIGHT SNOW IS ONLY EXPECTED TO
NET 1 TO 2 INCHES OF ACCUMULATIONS.
FOR TEMPERATURES...TODAY WILL BE SIMILAR TO FRIDAY AS CLOUDS
COMBINED WITH NORTH WINDS BRINGING DOWN THE ARCTIC AIR THAT IS
SITTING UP IN NRN MN HELPING TO LIMIT DIURNAL RANGES TODAY TO 5
DEGREES OR LESS. TONIGHT...THE ARCTIC AIR WILL FINALLY BE PUSHING
INTO THE MPX AREA...WHICH SHOULD ALLOW JUST ABOUT EVERYONE TO DIP
BELOW ZERO. TRENDED FORECAST LOWS TONIGHT TOWARD BIAS CORRECTED
VERSIONS OF THE ECMWF AND MET...WHICH RESULTED IN KNOCKING CLOSE 5
DEGREES OFF OF THE EXISTING FORECAST. IF WE CAN GET SKIES TO CLEAR
OUT...THEN TEMPS COULD GET COLDER STILL...ESPECIALLY OVER CENTRAL
MN WHERE LOWS IN THE -20S BELOW ZERO WOULD NOT BE OUT OF QUESTION.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 312 AM CST SAT DEC 14 2013
COLD NW FLOW WILL PERSIST ON THE BACKSIDE OF THE POTENT ERN
SEABOARD STORM OR SUN INTO MON AS RIDGING DEVELOPS OVER THE W
COAST. WHILE SFC HIGH PRES OVER S-CENTRAL CANADA...EXTENDING SWD
INTO THE DAKOTAS AND MN/WI...SEVERAL WAVES DRIVING SEWD WITHIN THE
FLOW ALOFT WILL ENCOUNTER ENHANCED H7-H5 LIFT AND A SWATH OF
RELATIVELY DEEPER MOISTURE. THIS COMBINATION WILL PRODUCE LIGHT
SNOW FOR SUN INTO MON. THOUGH WAA WILL COMMENCE DURG THE DAY ON
MON...THIS WAVE LOOKS TO EXIT THE REGION FAST ENOUGH SUCH THAT ANY
AND ALL PRECIP FROM IT SHALL REMAIN AS ALL -SN. SNOWFALL
ACCUMULATIONS WILL GENERALLY RANGE 1-2 INCHES...THOUGH IT IS
POSSIBLE THAT FAR ERN PORTIONS OF THE MPX CWFA /SPECIFICALLY...A
FEW WRN WI COUNTIES/ MAY RECEIVE UPWARDS OF 3-4 INCHES. STILL A
LITTLE BIT OF TIME TO IRON OUT THESE DETAILS.
MORE EXTENSIVE HIGH PRES WITH WARMER TEMPERATURES WILL CROSS THE
REGION TUE INTO WED...RESULTING IN HIGHER H5 HEIGHTS PRODUCING MAX
TEMPS INTO THE LOW-MID 20S WITH NO PRECIP EXPECTED.
ATTENTION THEN STILL IS FOCUSED ON THE END OF THE WEEK DUE TO THE
DEVELOPMENT OF A POTENT STORM SYSTEM DEVELOPING IN THE LEE OF THE
ROCKIES. AIDING THE DEVELOPMENT WILL BE THE WRN CONUS RIDGE
SHIFTING ACRS THE COUNTRY...PLACING THE SRN JET OVER THE
CYCLOGENESIS REGION AND ALLOWING A TRACK FOR IT TO MOVE NE. THERE
IS STILL MUCH UNCERTAINTY WITH REGARDS TO THE TRACK AND THE AMOUNT
OF WARM AIR ENTRAINED WITHIN THE SYSTEM. ATTM...THE TRACK OF THE
LOW PRES CENTER REMAINS S OF THE MPX CWFA...WHICH WOULD INDICATE
THAT THE PREVAILING P-TYPE IS -SN. HAVE ADVERTISED AS SUCH
ALTHOUGH THERE IS THE CAVEAT THAT IF THE TRACK SHIFTS FURTHER
N...THEN MULTIPLE P-TYPES MAY WELL BE INTRODUCED IN LATER
FORECASTS. THE SYSTEM DOES LOOK TO BE RATHER QUICK... TRACKING
FROM THE CO REGION NEWD INTO THE GREAT LAKES IN ABOUT 24 HRS. WITH
DEEP LONGWAVE TROUGHING AIDING ITS MOVEMENT...THE PRONOUNCED NW
FLOW BEHIND THIS SYSTEM WILL BRING DOWN ANOTHER ROUND OF ARCTIC
AIR STARTING THU NIGHT AND LASTING NOT ONLY FRIDAY BUT ALSO INTO
THE WEEKEND. SO...ALTHOUGH THERE IS LITTLE CONFIDENCE IN THE
DETAILS...THE OVERALL SCENARIO OF SEEING A POTENT WINTER STORM
FOLLOWED BY MUCH COLDER AIR IS LOOKING MORE REALISTIC BY THE MODEL
RUN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1129 AM CST SAT DEC 14 2013
LIGHT SNOW WILL CONTINUE EASTWARD INTO WISCONSIN...WITH A FEW
FLURRIES LAGGING BEHIND. LIGHT WINDS WILL GRADUALLY BECOME
NORTHWESTERLY. CEILINGS REMAIN THE BIGGEST CHALLENGE...AND AFTER A
FEW BREAKS THIS AFTERNOON SHOULD SEE MVFR CLOUDS RETURN LATER
TONIGHT ACROSS THE NORTHERN SITES. TOMORROW LIGHT SNOW WILL
DEVELOP IN WESTERN MN AFFECTING KAXN AND KRWF.
KMSP...
VFR CONDITIONS SHOULD HOLD MOST OF THE AFTERNOON. A FEW BRIEF
REDUCTION IN VISBYS ARE POSSIBLE WITH LINGERING LIGHT SNOW
SHOWERS. CONFIDENCE IS LOW IN THE MVFR CEILING FORECAST FOR THIS
EVENING. TOMORROWS SNOW SHOULD BE WEST AND SOUTH OF THE
METRO...WITH ONLY MID LEVEL CLOUDS EXPECTED AT KMSP.
/OUTLOOK FOR KMSP/
MON...VFR/MVFR WITH IFR/-SN POSSIBLE. WINDS SW AT 10KTS.
TUE...VFR WITH MVFR/-SN POSSIBLE. WINDS W AT 10KTS.
WED...VFR. WINDS VRBL AT 05KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...JPC
AVIATION...JRB
AREA FORECAST DISCUSSION
NWS DULUTH MN
1018 AM CST SAT DEC 14 2013
.UPDATE...
ISSUED AT 1017 AM CST SAT DEC 14 2013
LIGHT SNOW WAS FALLING ACROSS MOST OF THE NORTHLAND THIS
MORNING...WITH BANDS OF HEAVIER SNOWFALL OCCURRING FROM THE TWIN
PORTS NORTH ALONG THE NORTH SHORE. SPOTTERS AROUND LUTSEN AND
TOFTE HAVE HAD 3-4 INCHES SO FAR...WITH RATES OF 1 TO 1.5 INCHES
PER HOUR AT LUTSEN. CONDITIONS LOOK VERY FAVORABLE FOR PERIODS OF
HEAVIER SNOW BANDS FROM SILVER BAY THROUGH AT LEAST GRAND
MARAIS...SHIFTING AWAY FROM SILVER BAY EARLIER THIS AFTERNOON. WE
UPGRADED THE ADVISORY FOR COASTAL LAKE AND COOK COUNTIES TO A
WARNING WITH ADDITIONAL SNOWFALL OF 4 TO 7 INCHES...MAINLY BETWEEN
SILVER BAY AND GRAND MARAIS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CST SAT DEC 14 2013
HAS BEEN QUITE A NIGHT IN TERMS OF LAKE EFFECT SNOW. RECEIVED A
REPORT A SHORT TIME AGO OF CLOSE TO A FOOT OF SNOW FROM A VERY
SMALL LAKE EFFECT SNOW BAND THAT PARKED OVER THE CITY OF SUPERIOR
FRIDAY EVENING. AFTER BEING IN ONE LOCATION FOR SEVERAL HOURS...IT
HAD BASICALLY STARTED ITS PROGRESSION ALONG THE NORTH SHORE BY
MIDNIGHT. THE HEAVIEST SNOW BAND WAS JUST NORTHEAST OF GOOSEBERRY
FALLS STATE PARK AS OF 4 AM. THE HIGH RESOLUTION MODELS ARE
GENERALLY IN AGREEMENT THAT THE BANDS WILL CONTINUE TO MEANDER
ACROSS THE NORTH SHORE OF LAKE SUPERIOR TODAY. THE HRRR SEEMS TO
HAVE A FAIRLY DECENT HANDLE ON THE CURRENT LOCATION OF THE
HEAVIEST SNOW BAND...WITH LOCALLY HEAVY SNOW ACROSS LAKE COUNTY
THROUGH THE MORNING. THE HRRR AND MOST OF THE OTHER MODELS THEN
MIGRATE THAT AREA OF HEAVIER SNOW INTO COOK COUNTY FOR THE
AFTERNOON. GOING TO CONTINUE THE LAKE EFFECT SNOW ADVISORY...WITH
LOCALIZED 5 TO 7 INCHES...BUT COULD POTENTIALLY SEE MORE THAN THAT
IF THE BANDS PARK OVER ONE LOCATION FOR TOO LONG. WILL HAVE TO
KEEP A CLOSE EYE ON IT TODAY.
MEANWHILE...LIGHT SNOW WILL PROGRESS ACROSS MUCH OF THE NORTHLAND
TODAY. AMOUNTS WILL GENERALLY BE LIGHT WITH 1 TO 2 INCHES FOR MOST
AREAS.
ARCTIC HIGH PRESSURE WILL THEN BUILD DOWN BEHIND THE DEPARTING
WEAK LOW PRESSURE SYSTEM TONIGHT. HAVE DROPPED TEMPS
CONSIDERABLY...ESPECIALLY ACROSS THE NORTH. COULD SEE SOME -20S
ESPECIALLY ACROSS THE NORTH.
HAVE ALSO DROPPED TEMPS A BIT FOR SUNDAY...AS IT APPEARS SOME
NORTHERN LOCATIONS MAY STRUGGLE TO REACH ZERO DESPITE PARTIAL
SUNSHINE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 415 AM CST SAT DEC 14 2013
FAST MOVING SHORTWAVE WILL MOVE ACROSS THE CWA EARLY IN THE PERIOD
WITH A PERIOD OF LIGHT SNOW OCCURRING LATE SUNDAY NIGHT INTO EARLY
TUESDAY. BEYOND THAT THE UPPER JET WILL STRETCH ACROSS THE REGION
THROUGH EARLY THURSDAY. WITHIN THAT TIME PASSING SNOW SHOWERS ARE
POSSIBLE...MAINLY OVER THE NRN AND ERN CWA. ALL MED RANGE MDLS
SUPPORT THE MOVEMENT OF ANOTHER MID LVL TROF OVER THE REGION
THUR/FRI. POPS INCREASE LATE IN THE WEEK HOWEVER DOMINANT NRN BRANCH
OF UPPER JET WILL KEEP ANY SIGNIFICANT SFC DEVELOPMENT SOUTH AND
EAST OF THE AREA. TEMPS WILL MODERATE TO SOME EXTENT DURING THE EARLY
WEEK ESPECIALLY OVER THE SOUTH AND WEST AS FAST FLOW ALOFT KEEPS ANY
REINFORCING ARCTIC AIR FOCUSED JUST NORTH OF THE REGION ACROSS SRN
CANADA. LATE IN THE WEEK A DEVELOPING SFC LOW WILL MOVE FROM THE
PLAINS INTO THE LOWER GT LAKES. THIS SYSTEM WILL PULL ANOTHER SURGE
OF COLDER AIR SOUTH FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 551 AM CST SAT DEC 14 2013
LOW VFR/MVFR CEILINGS WILL TRANSITION TO MAINLY MVFR THIS MORNING
AS LIGHT SNOW CROSSES THE REGION. VISIBILITY MAY LOWER TO IFR AT
TIMES BUT CONFIDENCE NOT VERY HIGH AT THIS POINT. HIGHEST PROB OF
SNOW WILL BE THROUGH 00Z BEFORE INVERTED SFC TROUGH MOVES EAST AND
MOISTURE DECREASES. CYCLONIC MOIST FLOW WILL CONTINUE BEHIND
SYSTEM TONIGHT SO CLOUDS WILL BE SLOW TO DECREASE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 11 -11 1 -7 / 100 30 10 30
INL 3 -21 -3 -10 / 100 10 10 40
BRD 11 -13 3 -4 / 100 10 10 40
HYR 17 -8 4 -9 / 100 30 10 20
ASX 17 -1 8 -4 / 90 50 30 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...LAKE EFFECT SNOW ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ012.
LAKE EFFECT SNOW WARNING UNTIL 6 PM CST THIS EVENING FOR MNZ020-
021.
WI...NONE.
LS...NONE.
&&
$$
UPDATE...MELDE
SHORT TERM...DAP
LONG TERM...CANNON
AVIATION...CANNON
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1116 AM CST Sat Dec 14 2013
.SHORT TERM...(Today through Sunday Night)
Issued at 313 AM CST SAT DEC 14 2013
Winter storm is departing the region early this morning. Lingering
areas of drizzle will cause some minor icing from eastern KS into
western and central MO through sunrise as temperatures continue to
drop below freezing. Additional snow amounts will be mostly confined
to areas around Boonville and Moberly where another inch or so is
possible through early morning. An additional band of light snow has
developed from Kansas City into Chillicothe and Kirksville in
response to a narrow band of frontogenesis. RAP and NAM hold on to
this frontogenetical forcing through about 12Z and drop it to near
I-70, so it`s conceivable for this area of snow to hold together for
a few more hours and produce a dusting of snow with local amounts up
to a half inch near and northeast of KC. With temperatures falling
below freezing, any light snow that falls may fall on top of ice
developing on roads as lingering water freezes. Will therefore keep
the advisory going through 9 am as planned.
Precipitation will taper off from northwest to southeast through mid
morning. There`s a slight chance for some flurries or freezing
drizzle to redevelop late this morning into early afternoon as the
main upper trough axis swings through and interacts with low-level
cold air advection. Anything that does fall through this period
should be very light if anything at all.
Clouds will begin to scatter out later this afternoon and evening
with low-level ridging building in from the west. This will allow
temperatures to drop well into the single digits across northern and
central MO where a decent snow pack exists. Temperatures will begin
to moderate by Sunday and Sunday night with conditions returning to
near average.
.LONG TERM...(Monday through Friday)
Issued at 313 AM CST SAT DEC 14 2013
Monday - Tuesday:
General troughing across eastern Canada and the northern Great Lakes
will keep the area under benign northwest flow aloft. Nearer the
surface, downsloping westerly flow will allow temperatures to climb
where there is no snowpack. Highs across east central Kansas and
west central Missouri will rise into the mid to upper 40s whereas
across north central Missouri, where there is snowpack, highs will
only reach the mid to upper 30s. Tuesday a weak cold front will drop
through the area however this will have little effect on
temperatures as highs Tuesday should again range in the upper 30s to
upper 40s.
Wednesday:
The upper level pattern begins to shift on Wednesday becoming more
zonal across the region. Surface winds will also increase out of the
south providing for WAA and highs will be in the upper 30s to near
50. The next feature of interest, in the form of an upper level
trough, will move into the southwestern CONUS.
Thursday - Friday:
Models are in a bit of disagreement this far in the extended range.
However, the ECMWF, GFS and GEM all show the upper level shortwave
moving into the western Plains on Thursday and forcing a strong cold
front towards the area. Warm moist air streaming out ahead of this
front may produce light rain or drizzle on Thursday as high
temperatures move above average into the mid 40s to mid 50s. Models
depict rain changing to snow behind the front as it moves through
the area on Thursday night. The model differences occur on Friday as
the GFS stalls the front south of the area with snow continuing
through the day Friday whereas, the EC builds high pressure into the
area keeping conditions dry. On Friday, left the chance POPs in the
grids inherited by the initialization to account for the GFS
solution.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1114 AM CST SAT DEC 14 2013
A gradual improvement from the current MVFR cigs/vis is expected
over the next few hours. May see borderline MVFR/VFR cloud deck
currently over SE NE to approach from the north late this afternoon.
Period of clearing will be possible post-sunset before another wave
of VFR cloud cover moves into the area. Otherwise, wind speeds will
gradually decrease during the afternoon with a variable direction
overnight.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Hawblitzel
LONG TERM...73
AVIATION...Blair
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
556 PM EST SAT DEC 14 2013
.SYNOPSIS...
LOW PRESSURE WILL PASS WEST OF THE AREA TONIGHT...BRINGING PERIODS OF
RAIN INTO SUNDAY. A COLD FRONT WILL CROSS THE COAST EARLY ON
SUNDAY...BRINGING COOL AND DRY WEATHER INTO EARLY NEXT WEEK. DRY
AND SEASONABLE WEATHER EXPECTED MUCH OF NEXT WEEK AS SURFACE HIGH
PRESSURE IS REINFORCED OVER THE AREA. A LOW PRESSURE SYSTEM WILL
APPROACH THE AREA NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 PM SATURDAY...SWIFT COLUMN WINDS ARE TRANSPORTING
INCREASING MOISTURE INTO THE AREA AS PRECIPITABLE WATERS CLIMB
THIS AFTERNOON ACROSS THE FORECAST AREA. KLTX VAD WIND PROFILE
CLOCKING 40 KNOT BARBS IN THE LOWEST GATES ADVECTING HIGHER
BOUNDARY LAYER DEWPOINTS OFF THE ATLANTIC ONTO LAND...WHILE ALOFT
A 50-70 KT SOUTHWEST TRAJECTORIES WERE STREAMING GULF MOISTURE
INTO THE CAROLINAS. LATEST SATELLITE-SENSED PWAT LOOPS DEPICT PWAT
VALUES IN EXCESS OF 1-INCH CROSSING THE SC/NC BORDER.
A WARM FRONT IS PUSHING NW ACROSS OUR FORECAST AREA PRESENTLY.
GUSTY SE WINDS AND RISING T/TD VALUES CHARACTERIZED CONDITIONS
EAST OF THE BOUNDARY. THIS TREND WILL CONTINUE INTO EARLY EVENING
INCREASING INSTABILITY OVER THE AREA AND MOST NOTABLY ALONG THE
COAST WHERE HIGHER TD VALUES ARE ANTICIPATED.
A NEARLY MOIST ADIABATIC SOUNDING PROFILE TONIGHT WILL LIMIT
OVERALL INSTABILITY BUT MOST OF THE MODELS APPEAR TO GENERATE CAPE
VALUES THIS EVENING SUFFICIENT FOR A FEW UPDRAFTS...AND BESIDES WE
SHOULD HAVE ADEQUATE JET SUPPORT ALOFT. OVERLAYED TEMPORALLY WITH
THIS INSTABILITY MAXIMA MAINLY BETWEEN 0Z/7PM AND 6Z/1AM...ARE
ELEVATED 0-3 KM HELICITY VALUES...AS CYCLOGENESIS PROMPTS A
DEEPENING WAVE OF LOW PRESSURE ALONG THE FRONT THAT TRACKS OVER
THE AREA THIS EVENING. THERE REMAINS ENOUGH INGREDIENTS TO RETAIN
A MENTION OF POTENTIALLY DAMAGING WINDS WITH ANY THUNDERSTORMS
THAT MAY FORM...DUE TO DYNAMIC WIND-FIELDS AND FAVORABLE HELICITY
AND HODOGRAPH PROFILES. THE BEST VERTICAL SHEAR PROFILES CONTINUE
TO REMAIN ALONG THE COAST AND COASTAL INTERIOR ALTHOUGH ANY ONE
LOCATION ACROSS THE FORECAST AREA WOULD POSSESS A SMALL CHANCE OF
WIND-DAMAGE AS THE FRONT TRANSITS.
COOL AIR ADVECTION LATER TONIGHT WILL BRING OUR MILD TEMPERATURES
DOWN EVEN THOUGH WIND DIRECTIONS MAY BE ESSENTIALLY WEST TO EAST
HAVING CRESTED THE APPALACHIANS BEFORE THE LEADING EDGE OF HIGH
PRESSURE ARRIVES. MINIMUMS THEREFOR IN THE MIDDLE TO UPPER 50S
THE COAST AND A CHILLIER MIDDLE UPPER 40S ACROSS OUR FAR INTERIOR.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 230 PM SATURDAY...THE SHORT TERM FORECAST IS RATHER STRAIGHT FORWARD AS
THE MID LEVEL TROUGH WILL CONTINUE TO MOVE OFFSHORE SUNDAY WITH A
MODEST NORTHWEST FLOW ENSUING THROUGH THE REMAINDER OF THE PERIOD.
AT THE SURFACE...HIGH PRESSURE BUILDS IN FROM THE NORTHWEST THEN THE
SURFACE PATTERN SHOWS A WEAKNESS DEVELOPING LATER MONDAY. ALTHOUGH
THERE ARE WEAK SHORTWAVES IN THE FLOW...NONE ARE STRONG ENOUGH TO
REINFORCE THE MODEST COLD AIR ADVECTION THAT MOVES IN SUNDAY.
OVERALL GUIDANCE REMAINS IN GOOD AGREEMENT WITH HIGHS IN THE 50S AND
LOWS IN THE 30S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...ZONAL FLOW ON TUESDAY EVEN AS IMPRESSIVE JET
OF 100KT DIVES ACROSS NRN PLAINS. THE MID LEVEL WAVE WRAPS UP FAIRLY
QUICKLY AND THUS DOES NOT LEAD TO A VERY DEEP TROUGH. EVEN SO IT
WILL MANAGE TO PUSH A RAIN-FREE COLD FRONT THROUGH THE CAROLINAS
TUESDAY NIGHT. HIGH RISES ALREADY UNDERWAY THOUGH WEDNESDAY MORNING
AS THE SYSTEM ALOFT SWINGS NEGATIVE AND LIFTS INTO NEW ENGLAND.
WEDNESDAY IS WHEN SURFACE PRESSURE GRADIENT FINALLY BECOMES LESS
NOISY AS HIGH PRESSURE CONGEALS OVER THE NC SOUNDS WHILE SUBTLE MID
LEVEL HEIGHT RISES CONTINUE. SURFACE RIDGE MOVES CONSIDERABLY TO THE
EAST FOR THE LATE WEEK PERIOD AND MID LEVEL TROUGHINESS DEVELOPS
OVER THE SWRN U.S. BOUNDARY LAYER WARMTH AND MOISTURE WILL BE ON THE
RISE BUT NOT SUFFICIENTLY FOR ANY MEANINGFUL RAIN CHANCES.
&&
.AVIATION /00Z SATURDAY THROUGH THURSDAY/...
AS OF 00Z...CONVECTION ONGOING WITH BRIEF PERIODS OF 1-2SM
VISIBILITY IN HEAVY SHOWERS...WITH ISOLATED EMBEDDED THUNDER. STRONG
HELICITY COUNTERED BY WEAK CAPE WILL LIKELY PRODUCE ISOLATED SEVERE
WEATHER. MOST OF THE ACTIVITY WILL BE OVER BY 03Z. THE HRRR HAS A
SECONDARY LINE MOVING FROM WEST TO EAST ALONG THE FRONT...BUT THE
AREA IS WEAKER THAN THE EARLIER MAIN LINE. LOOK FOR BRIEF BOUTS OF
IFR STRATUS. OVERNIGHT...CONDITIONS WILL IMPROVE AS THE THE FRONT
MOVES THROUGH. WINDS WILL SHIFT TO THE WEST...REMAINING ELEVATED.
SHOWERS WILL END FROM WEST TO EAST BY 06-08Z. BECOMING VFR TOWARD
MORNING...CONTINUING ON SUNDAY WITH A GUSTY NORTHWEST WIND.
EXTENDED OUTLOOK...SHOWERS LIKELY WITH PERIODS OF MVFR/IFR
CONDITIONS INTO EARLY SUNDAY. VFR DEVELOPING SUNDAY AND
PERSISTING THROUGH MID-WEEK.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 230 PM SATURDAY...DANGEROUS MARINE CONDITIONS OVERNIGHT AS A
MODERATELY STRONG COLD FRONT CROSSES THE AREA AND JACKS UP SW
WINDS IN ADVANCE THROUGH EARLY SUNDAY....WITH SW 20-30 KT LIKELY
OVER THE WATERS. A FEW GALE GUSTS BEYOND 20 NM IN WARMER WATERS
IS POSSIBLE...SUCH AS THE FRYING PAN SHOALS AREA. SEAS OF 5-9 FT
EXPECTED AND HIGHEST OFFSHORE...COMPOSED MAINLY OF LARGE S WAVES
EVERY 6-8 SECONDS. SEVERAL STRONG TSTMS ARE POSSIBLE ON THE WATERS
TONIGHT...AND WILL BE CAPABLE OF GENERATING GUSTS TO 50KT IN
ISOLATED MARINE LOCATIONS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 230 PM SATURDAY...INITIALLY A WESTERLY FLOW WILL BE IN PLACE OVER
THE WATERS IN A RANGE OF 15-20 KNOTS. AS SUNDAY PROGRESSES...WINDS
WILL OBTAIN A MORE NORTHWESTERLY COMPONENT AND DECREASE. THE WINDS
WILL VERY GRADUALLY DIMINISH TO 10-15 KNOTS THROUGH THE REMAINDER
OF THE PERIOD. AS FOR SEAS...THE CHANGE IN FETCH WILL BE WELL
UNDERWAY EARLY WITH A FEW SIX FOOTERS REMAINING ACROSS THE OUTER
WATERS WITH A WIDE RANGE OF 2-6 FEET. SEAS WILL GRADUALLY DIMINISH
TO 2-3 FEET BY MONDAY.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 230 PM SATURDAY...WEST TO SOUTHWEST WINDS PICK UP AHEAD OF A
COLD FRONT ON TUESDAY. THE OFFSHORE FLOW DIRECTION BUILDS SEAS AWAY
FROM SHORE TO 3 OR 4 FT WHILE LANDMASS WAVE SHADOWING KEEPS THE
NEARSHORE WAVES CLOSER TO 2 FT. VEERING FLOW BEHIND THE BOUNDARY ON
WEDNESDAY TO SHORTEN THE PERIOD SOMEWHAT AS WAVE FACES STEEPEN BUT
LITTLE OVERALL CHANGE IN SIG WAVE HEIGHT EXPECTED. THURSDAY PUTS US
INTO A SOUTHERLY RETURN FLOW REGIME THAT WILL LAST FOR SEVERAL DAYS.
ANY BUILDING OF SEAS WILL BE GRADUAL AND LIKELY NOT OCCUR UNTIL
AFTER THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST SUNDAY FOR AMZ250-252-254-
256.
&&
$$
SYNOPSIS...SHK
NEAR TERM...MJC
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...43
AREA FORECAST DISCUSSION
NWS RALEIGH NC
255 PM EST SAT DEC 14 2013
.SYNOPSIS...LOW PRESSURE AND A COLD FRONT WILL MOVE ACROSS THE
REGION TONIGHT. HIGH PRESSURE WILL THEN PROVIDE FAIR WEATHER
ACROSS OUR AREA THROUGH MUCH OF NEXT WEEK.
&&
NEAR TERM /THROUGH TONIGHT/...
AS OF 255 PM SATURDAY...
CURRENT PATTERN FEATURES A POSITIVELY TILTED L/W TROUGH MVG ACROSS
THE MIDDLE OF THE COUNTRY WITH A WELL DEFINED EMBEDDED S/W MOVING NE
ALONG THE OH RIVER VALLEY...AND ANOTHER S/W IN THE BASE OF THE L/W
TROUGH MVG ACROSS THE SRN PLAINS. A CLASSIC MILLER TYPE-B
CYCLOGENESIS PATTERN IS UNFOLDING ACROSS THE REGION ATTM WITH LOW
PRESSURE AND AN ASSOC COLD FRONT MVG ACROSS THE TN VALLEY AND
CYCLOGENESIS NOW OCCURRING OVER THE CAROLINAS WITH SEVERAL RECENT
OBS SHOWING RAPID PRESSURE FALLS FROM NORTHCENTRAL SC NEWD ACROSS
THE NC SANDHILLS AND COASTAL PLAIN. THE WEDGE BOUNDARY CONTINUES
ALONG AND WEST OF THE I-85 CORRIDOR STRENGTHENED BY ONGOING RAIN
ACROSS WESTERN PIEDMONT...WHILE THE COASTAL FRONT HAS BEEN SLOW TO
PUSH INLAND AND STILL LOCATED NEAR THE COAST. MEANWHILE...A LARGE
PRECIP SHIELD ASSOC WITH THE ADVANCING SHORT WAVES AND PREFRONTAL
TROUGH HAS CROSSED THE MOUNTAINS AND IS WELL-DEPICTED BY NEAR-TERM
GUIDANCE AND PROGGED TO CONTINUE MOVING ACROSS OUR CWA THROUGH THIS
EVENING INTO THE EARLY OVERNIGHT HOURS. THE HEAVIEST RAIN IS
EXPECTED TO OCCUR ACROSS OUR WESTERN ZONES AND THE TRIAD REGION
BETWEEN NOW AND 22Z...ACROSS OUR CENTRAL ZONES AND THE TRIANGLE
REGION BETWEEN 21Z AND 00Z...AND ACROSS OUR COASTAL PLAIN ZONES
BETWEEN 23Z AND 03Z.
THE PRIMARY CONCERN FOR THIS EVENING IS THE POTENTIAL FOR THUNDER.
WHILE PRESSURE IS FALLING RAPIDLY ATTM ACROSS THE SANDHILLS AND
COASTAL PLAIN REGION...AND THE SFC LOW IS EXPECTED TO MOVE NE ALONG
OR TO THE EAST OF THE I-95 CORRIDOR...THE AIRMASS WITH THE BEST
BUOYANCY IS STILL S/E OF THE COASTAL FRONT. AS PRESSURES CONTINUE TO
FALL AND THE LOW FURTHER DEVELOPS...WE MAY YET SEE AN INLAND
ADVANCEMENT OF THIS BOUNDARY. HOWEVER...THE CURRENT PRESSURE FALLS
AND SFC TEMP/WIND OBS SUGGEST THAT THE BEST TEMP/DWPT ADVECTION (AND
THUS INSTABILITY) SHOULD REMAIN MOSTLY EAST OF OUR CWA. AS SUCH...
RIGHT NOW THE BEST CHANCE FOR THUNDER IN OUR CWA APPEARS TO BE
ACROSS OUR FAR E/SE ZONES. PRIMARY IMPACTS WITH TSTMS ACROSS OUR
AREA SHOULD BE LIMITED TO SCATTERED HEAVY DOWNPOURS AND PERHAPS A
BRIEF WIND GUST OR TWO BELOW SVR LIMITS. NONETHELESS...THESE
SCATTERED HEAVIER DOWNPOURS MAY RESULT IN BRIEF PERIODS OF LOW
VISIBILITY AND WATER PONDING IN THE TYPICAL POOR DRAINAGE AREAS.
WHILE THE STEADY PRECIP IS EXPECTED TO END ACROSS OUR WESTERN ZONES
BY 02-03Z AND OUR EASTERN ZONES BY 05-06Z...LATEST HRRR SHOWS SOME
LIGHT PRECIP REDEVELOPMENT ASSOC WITH SFC FRONT AFT MIDNIGHT...SO
WILL KEEP A LINGERING 20-40 PERCENT POP GOING OVERNIGHT THROUGH 09Z.
IN ADDITION...FORECAST SOUNDINGS CONTINUE TO SHOW THE SFC NEARLY
SATURATED WITH LIGHT WINDS...THUS LOOK FOR LOW CLOUDS AND SOME FOG
TO PERSIST THROUGH SUNRISE. LOWS TONIGHT WILL RANGE FROM THE MID 30S
NW TO MID 40S SE.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 255 PM SATURDAY...
AFTER SUNRISE SUNDAY...SKIES WILL BEGIN TO CLEAR OUT AS NW LOW LEVEL
FLOW INCREASES BEHIND THE DEPARTING LOW AND BL MIXING HELPS TO DRY
OUT THE AIRMASS. AS MIXING INCREASES THROUGH THE MORNING...WE MAY
SEE A FEW HOURS OF 15-20 MPH WIND GUSTS FROM THE NW. OTHERWISE...
LOOK FOR PLENTY OF SUNSHINE...WITH HIGHS NEAR SEASONAL VALUES IN THE
LOW-MID 50S.
MAINLY CLEAR SKIES AND LIGHT WINDS WILL PROMOTE GOOD RADIATIONAL
COOLING SUNDAY NIGHT. LOWS WILL RANGE FROM THE UPPER 20S NW TO LOWER
30S E...A FEW DEGREES BELOW NORMAL.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 235 PM SATURDAY...
A LOW PRESSURE SYSTEM DIVING OUT OF THE CANADIAN ROCKIES WILL
APPROACH THE GREAT LAKES AND DIVE THROUGH NEW ENGLAND AS AN UPPER
LEVEL TROUGH DIGS DOWN THE EASTERN SEABOARD BUT WILL HAVE A HARD
TIME EXTENDING SOUTHWARD. THIS WILL MAKE UPPER LEVEL FLOW MORE ZONAL
OVER NORTH CAROLINA CAUSING A FAIRLY CONSTANT TEMPERATURE PATTERN
WITH SOME OSCILLATION IN HIGH AND LOW TEMPS FOR THE FIRST TWO THIRDS
OF THE PERIOD. BY THE END OF THE WEEK A FEW SHORTWAVES DEVELOP IN
THE SOUTHERN STREAM AND STRONG WARM AIR ADVECTION TAKES TEMPERATURES
WELL ABOVE SEASONAL NORMALS FOR FRIDAY AND SATURDAY BEFORE A
STRONGER LOW DEVELOPS AND MOVES THROUGH THE OHIO VALLEY ON SUNDAY.
MONDAY AND TUESDAY: WHILE MODELS GENERALLY KEEP THE PATTERN THE SAME
...THE GFS HAS A BROADER SURFACE HIGH OVER THE REGION...THUS
SHUTTING OFF ANY SLIGHT COLD AIR ADVECTION ON THE FRONT SIDE OF THE
HIGH. THE ECMWF HANGS BACK WITH THIS AND THUS ITS TEMPERATURES ARE
COOLER. EITHER WAY A SLIGHT WARMING TREND FROM MONDAY TO TUESDAY
WITH UPPER 40S TO LOW 50S EXPECTED MONDAY AND MID 50S ON TUESDAY.
DRY AND MOSTLY CLEAR WITH VERY LIGHT WINDS OUT OF THE NORTHWEST.
LOWS IN THE LOWER TO MID 30S.
WEDNESDAY AND THURSDAY: A MORE NORTHWESTERLY UPPER LEVEL FLOW AND A
TIGHTER GRADIENT IN THE GFS YIELD SOME LOWER TEMPERATURES FOR
WEDNESDAY BUT THE PATTERN IS MORE RELAXED IN THE LATEST EUROPEAN
WITH MOST OF THE STRONGER DYNAMICS WELL TO THE NORTH. WILL INDICATE
A SMALL REDUCTION IN HIGHS ON WEDNESDAY...LOWER TO MID 50S WITH LOWS
IN THE LOWER 30S THURSDAY MORNING. ON THURSDAY UPPER LEVEL FLOW WILL
BEGIN TO BACK AROUND TO WESTERLY AND THEN SOUTHWESTERLY. AT THE SAME
TIME THE SURFACE HIGH MOVES OFF SHORT. THIS WILL BEGIN A PERIOD OF
SIGNIFICANT WARM AIR ADVECTION WHICH WILL PUT HIGHS ON THURSDAY INTO
THE MID TO UPPER 50S WITH LOWS IN THE LOWER 40S.
FRIDAY AND SATURDAY: AS FLOW BECOMES MORE SOUTHWESTERLY...INCREASED
WARM AIR ADVECTION WILL HELP TEMPERATURES RISE ABOVE SEASONAL
NORMALS. INCREASED MOISTURE AHEAD OF A DEVELOPING FRONTAL ZONE IN
THE TN VALLEY WILL BEGIN TO BRING MORE CLOUDS INTO THE AREA AND A
SLIGHT CHANCE OF SOME DRIZZLE OR LIGHT RAIN FRIDAY AFTERNOON AND
EVENING...INCREASING TO CHANCE OF RAIN BY SATURDAY. HIGHEST
POTENTIAL FOR RAIN WILL BE IN THE NORTHWEST. HIGHS POTENTIALLY
RISING TO THE MID TO UPPER 60S BY SATURDAY...ALMOST 15 DEGREES ABOVE
NORMAL FOR THIS TIME OF YEAR.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 100 PM SATURDAY...
AVIATION CONDITIONS WILL CONTINUE TO DETERIORATE THE REMAINDER OF
THIS AFTERNOON AS THE MAIN RAIN SHIELD TO OUR WEST CONTINUES TO MOVE
EAST. LOOK FOR WIDESPREAD LOW-MVFR AND IFR CONDITIONS (ISOLD POCKETS
OF LIFR) TO DEVELOP ACROSS MOST OF CENTRAL NC BETWEEN NOW AND 21Z.
THE RAIN IS EXPECTED TO END FROM WEST TO EAST BETWEEN 03Z-06Z AS THE
FRONT MOVES THROUGH AND LOW PRESSURE EXITS TO OUR E/NE. HOWEVER IFR
CONDITIONS WITH LOW CLOUDS AND FOG MAY PERSIST FOR THE REMAINDER OF
THE NIGHT DUE TO LINGERING LOW LEVEL MOISTURE. AFTER SUNRISE...LOOK
FOR FLIGHT CONDITIONS TO IMPROVE TO VFR AS WINDS BECOME NW AND DRIER
AIR MOVES INTO THE REGION...RESULTING IN CLEARING SKIES.
OTHERWISE...LOW LEVEL WIND SHEAR MAY STILL POSE A THREAT TO AVIATORS
THROUGH THIS EVENING AS SURFACE WINDS FROM THE EAST AT SPEEDS LESS
THAN 12 KTS ARE TOPPED BY 30-40 KT WINDS AROUND 2000 FT AGL FROM THE
SOUTH. HOWEVER...THIS CONCERN HAS BEEN DIMINISHING SOME DURING THE
PAST FEW HOURS AS LOCAL WVPS HAVE BEEN SHOWING SPEEDS AROUND 2K FT
WEAKENING JUST A BIT.
LOOKING BEYOND 18Z SUNDAY...VFR CONDITIONS EXPECTED THROUGH MID-
WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...NP
NEAR TERM...NP
SHORT TERM...NP
LONG TERM...ELLIS
AVIATION...NP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
237 PM EST SAT DEC 14 2013
.SYNOPSIS...A STORM SYSTEM WILL TRACK FROM THE SOUTHERN MISSISSIPPI
VALLEY NORTHEAST ACROSS THE CAROLINAS AND MID ATLANTIC REGION
THROUGH THE WEEKEND. HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST
LATE SUNDAY THROUGH TUESDAY.
&&
.NEAR TERM /TODAY THROUGH TONIGHT/... AS OF 1055 AM SATURDAY...
LATEST REGIONAL ANALYSIS SHOWS A WARM FRONT ALONG THE COAST
GRADUALLY MOVING ONSHORE. LIGHT RAIN SHOWERS HAVE BEEN FORMING ALONG
THIS BOUNDARY AND MOVING INLAND AND NORTH ACROSS THE SOUTHERN
COASTAL PLAIN. FARTHER WEST...A LARGE SHIELD OF LIGHT TO MODERATE
RAIN...ASSOCIATED WITH THE LARGER SYNOPTIC SCALE TROUGH AND COMPLEX
SFC LOW PATTERN...IS STEADILY MOVING EWD ACROSS THE MOUNTAINS AND
APPROACHING THE WESTERN PIEDMONT. A TYPICAL WEDGE FRONT HAS BEEN
TAKIN SHAPE THE PAST FEW HOURS AND IS GENERALLY POSITIONED ACROSS
THE ERN FOOTHILLS/WRN PIEDMONT ATTM. THE NEAR-TERM MODELS SUCH AS
THE RAP AND HRRR HAVE A FAIRLY GOOD HANDLE ON THE PATTERN AND
REFLECT OUR CONCEPTUAL IDEA FOR THE REST OF TODAY. LOOK FOR THE RAIN
TO OUR W TO CONTINUE TO MOVE E AND EXPAND ACROSS OUR CWA AS THE DAY
PROGRESSES AS THE LARGER SCALE SYSTEM CONTINUES TO DRIFT E. THE
AFOREMENTIONED RAIN SHOULD FURTHER STRENGTHEN THE LOW LEVEL WEDGE
AND ASSOC BOUNDARY ACROSS WESTERN PIEDMONT...SO TEMPS THERE NOT
EXPECTED TO INCREASE MUCH FROM CURRENT READINGS IN THE U30S TO L40S.
MEANWHILE...THE WARM FRONT FARTHER EAST IS EXPECTED TO GRADUALLY
PUSH INLAND...WITH TEMPS ACROSS OUR E/SE ZONES CLIMBING THROUGH THE
50S AS THE AFTERNOON PROGRESSES. IN BETWEEN THESE TWO BOUNDARIES
ACROSS OUR CNTRL ZONES...TEMPS EXPECTED TO ONLY SLOWLY RISE INTO THE
UPPER 40S TO PERHAPS LOWER 50S.
IN TERMS OF PRECIP...AS ELUDED TO...THE STEADIER LIGHT/MOD PRECIP
ENTERING OUR WRN ZONES WILL CONTINUE TO GRADUALLY SPREAD EWD...SO
THROUGH EARLY AFTERNOON...LOOK FOR RAIN TO BECOME DEVELOP AND BECOME
STEADY ACROSS OUR FAR W/NW ZONES (TRIAD)...WHILE FURTHER E...THE
RAIN WILL BE MORE SCATTERED AND SHOWERY IN NATURE. THEN LATER THIS
AFTERNOON...LOOK FOR THE RAIN TO BECOME STEADY ACROSS MUCH OF OUR
CWA AS THE LOW LEVEL JET AND LARGER SCALE FORCING CURRENTLY TO OUR W
SHIFTS E ACROSS OUR AREA. BY THIS EVENING...THE PRECIP ACROSS OUR
ERN ZONES MAY BECOME MORE CONVECTIVE IN NATURE WITH THE POTENTIAL
FOR A FEW HEAVIER DOWNPOURS AS THE AFOREMENTIONED LOW LEVEL JET AND
LARGER SYNOP SCALE FORCING ENCOUNTERS THE COASTAL BOUNDARY WHICH
SHOULD BE POSITIONED SOMEWHERE ALONG OR TO THE EAST OF I-95 BY THAT
TIME. FORECAST SOUNDINGS HOWEVER SHOW WHAT LITTLE INSTABILITY THERE
IS TO BE ELEVATED...SO IMPACTS W/CONVECTION...AT LEAST AS IT APPEARS
AT THIS POINT...SHOULD BE LIMITED TO SCATTERED HEAVY DOWNPOURS AND
PERHAPS A BRIEF WIND GUST OR TWO BELOW SVR LIMITS. NONETHELESS...
THESE SCATTERED HEAVIER DOWNPOURS MAY RESULT IN BRIEF PERIODS OF LOW
VISIBILITY AND WATER PONDING IN THE TYPICAL POOR DRAINAGE AREAS.
PRECIP EXPECTED TO END ACROSS OUR WRN ZONES BY 8 PM OR SO...AND
ACROSS OUR ERN ZONES SHORTLY AFT MIDNIGHT. -NP
WILL TAPER DOWN POPS WNW TO ESE LATE TONIGHT. MODEL SOUNDINGS SHOW
THE LOW LEVELS REMAINING VERY MOIST AND STABLE... SO EXPECT LOW
CLOUDS AND FOG TO HOLD IN INTO THE OVERNIGHT HOURS... BEFORE FINALLY
LIFTING AND MIXING OUT AS THE SYSTEM CONGEALS INTO A SINGLE LOW JUST
OFF NYC TOWARD SUNRISE SUNDAY. LOWS FROM 33 NW TO 47 SE. -GIH
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM SATURDAY...
AFTER SOME MORNING CLOUDINESS ASSOCIATED WITH THE WEAK SURFACE
TROUGH TRAILING FROM THE COASTAL LOW OFF NYC... THE ENSUING
DOWNSLOPE LOW LEVEL FLOW WILL HELP DRY OUT THE LOWER TROPOSPHERE...
AS INCREASING DEEP LAYER SUBSIDENCE IN THE WAKE OF THE DEPARTING
BROAD TROUGH AXIS HELPS DRY AND STABILIZE THE MID-UPPER LEVELS.
EXPECT PLENTY OF SUNSHINE BY THE AFTERNOON HOURS. THICKNESSES DO
FALL DURING THE DAY (MUCH OF WHICH IS A FUNCTION OF COOLING AT 925-
850 MB WITH A MORE TYPICAL DIURNAL TREND NOTED BELOW 925 MB ALBEIT
WITH SHALLOW MIXING)... BUT THE INCOMING AIR MASS IS MODIFIED AND
SOURCED FROM OUR WSW... AND LATE-DAY THICKNESSES ARE STILL JUST
SLIGHTLY BELOW NORMAL. HIGHS 51-57... CLOSE TO SEASONAL NORMALS.
LOWS 26-33 AS A PORTION OF THE SURFACE HIGH NOSES IN FROM THE SW
CAUSING WINDS TO BECOME LIGHT WITH MOSTLY CLEAR SKIES FACILITATING
RADIATIONAL COOLING. -GIH
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 235 PM SATURDAY...
A LOW PRESSURE SYSTEM DIVING OUT OF THE CANADIAN ROCKIES WILL
APPROACH THE GREAT LAKES AND DIVE THROUGH NEW ENGLAND AS AN UPPER
LEVEL TROUGH DIGS DOWN THE EASTERN SEABOARD BUT WILL HAVE A HARD
TIME EXTENDING SOUTHWARD. THIS WILL MAKE UPPER LEVEL FLOW MORE ZONAL
OVER NORTH CAROLINA CAUSING A FAIRLY CONSTANT TEMPERATURE PATTERN
WITH SOME OSCILLATION IN HIGH AND LOW TEMPS FOR THE FIRST TWO THIRDS
OF THE PERIOD. BY THE END OF THE WEEK A FEW SHORTWAVES DEVELOP IN
THE SOUTHERN STREAM AND STRONG WARM AIR ADVECTION TAKES TEMPERATURES
WELL ABOVE SEASONAL NORMALS FOR FRIDAY AND SATURDAY BEFORE A
STRONGER LOW DEVELOPS AND MOVES THROUGH THE OHIO VALLEY ON SUNDAY.
MONDAY AND TUESDAY: WHILE MODELS GENERALLY KEEP THE PATTERN THE SAME
...THE GFS HAS A BROADER SURFACE HIGH OVER THE REGION...THUS
SHUTTING OFF ANY SLIGHT COLD AIR ADVECTION ON THE FRONT SIDE OF THE
HIGH. THE ECMWF HANGS BACK WITH THIS AND THUS ITS TEMPERATURES ARE
COOLER. EITHER WAY A SLIGHT WARMING TREND FROM MONDAY TO TUESDAY
WITH UPPER 40S TO LOW 50S EXPECTED MONDAY AND MID 50S ON TUESDAY.
DRY AND MOSTLY CLEAR WITH VERY LIGHT WINDS OUT OF THE NORTHWEST.
LOWS IN THE LOWER TO MID 30S.
WEDNESDAY AND THURSDAY: A MORE NORTHWESTERLY UPPER LEVEL FLOW AND A
TIGHTER GRADIENT IN THE GFS YIELD SOME LOWER TEMPERATURES FOR
WEDNESDAY BUT THE PATTERN IS MORE RELAXED IN THE LATEST EUROPEAN
WITH MOST OF THE STRONGER DYNAMICS WELL TO THE NORTH. WILL INDICATE
A SMALL REDUCTION IN HIGHS ON WEDNESDAY...LOWER TO MID 50S WITH LOWS
IN THE LOWER 30S THURSDAY MORNING. ON THURSDAY UPPER LEVEL FLOW WILL
BEGIN TO BACK AROUND TO WESTERLY AND THEN SOUTHWESTERLY. AT THE SAME
TIME THE SURFACE HIGH MOVES OFF SHORT. THIS WILL BEGIN A PERIOD OF
SIGNIFICANT WARM AIR ADVECTION WHICH WILL PUT HIGHS ON THURSDAY INTO
THE MID TO UPPER 50S WITH LOWS IN THE LOWER 40S.
FRIDAY AND SATURDAY: AS FLOW BECOMES MORE SOUTHWESTERLY...INCREASED
WARM AIR ADVECTION WILL HELP TEMPERATURES RISE ABOVE SEASONAL
NORMALS. INCREASED MOISTURE AHEAD OF A DEVELOPING FRONTAL ZONE IN
THE TN VALLEY WILL BEGIN TO BRING MORE CLOUDS INTO THE AREA AND A
SLIGHT CHANCE OF SOME DRIZZLE OR LIGHT RAIN FRIDAY AFTERNOON AND
EVENING...INCREASING TO CHANCE OF RAIN BY SATURDAY. HIGHEST
POTENTIAL FOR RAIN WILL BE IN THE NORTHWEST. HIGHS POTENTIALLY
RISING TO THE MID TO UPPER 60S BY SATURDAY...ALMOST 15 DEGREES ABOVE
NORMAL FOR THIS TIME OF YEAR.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 100 PM SATURDAY...
AVIATION CONDITIONS WILL CONTINUE TO DETERIORATE THE REMAINDER OF
THIS AFTERNOON AS THE MAIN RAIN SHIELD TO OUR WEST CONTINUES TO MOVE
EAST. LOOK FOR WIDESPREAD LOW-MVFR AND IFR CONDITIONS (ISOLD POCKETS
OF LIFR) TO DEVELOP ACROSS MOST OF CENTRAL NC BETWEEN NOW AND 21Z.
THE RAIN IS EXPECTED TO END FROM WEST TO EAST BETWEEN 03Z-06Z AS THE
FRONT MOVES THROUGH AND LOW PRESSURE EXITS TO OUR E/NE. HOWEVER IFR
CONDITIONS WITH LOW CLOUDS AND FOG MAY LFRIDAY NIGHTINGER FOR THE REMAINDER OF
THE NIGHT DUE TO LINGERING LOW LEVEL MOISTURE. AFTER SUNRISE...LOOK
FOR FLIGHT CONDITIONS TO IMPROVE TO VFR AS WINDS BECOME NW AND DRIER
AIR MOVES INTO THE REGION...RESULTING IN CLEARING SKIES.
OTHERWISE...LOW LEVEL WIND SHEAR MAY STILL POSE A THREAT TO AVIATORS
THROUGH THIS EVENING AS SURFACE WINDS FROM THE EAST AT SPEEDS LESS
THAN 12 KTS ARE TOPPED BY 30-40 KT WINDS AROUND 2000 FT AGL FROM THE
SOUTH. HOWEVER...THIS CONCERN HAS BEEN DIMINISHING SOME DURING THE
PAST FEW HOURS AS LOCAL WVPS HAVE BEEN SHOWING SPEEDS AROUND 2K FT
WEAKENING JUST A BIT.
LOOKING BEYOND 18Z SUNDAY...VFR CONDITIONS EXPECTED THROUGH MID-
WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...NP/HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...NP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
100 PM EST SAT DEC 14 2013
.SYNOPSIS...A STORM SYSTEM WILL TRACK FROM THE SOUTHERN MISSISSIPPI
VALLEY NORTHEAST ACROSS THE CAROLINAS AND MID ATLANTIC REGION
THROUGH THE WEEKEND. HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST
LATE SUNDAY THROUGH TUESDAY.
&&
.NEAR TERM /TODAY THROUGH TONIGHT/... AS OF 1055 AM SATURDAY...
LATEST REGIONAL ANALYSIS SHOWS A WARM FRONT ALONG THE COAST
GRADUALLY MOVING ONSHORE. LIGHT RAIN SHOWERS HAVE BEEN FORMING ALONG
THIS BOUNDARY AND MOVING INLAND AND NORTH ACROSS THE SOUTHERN
COASTAL PLAIN. FARTHER WEST...A LARGE SHIELD OF LIGHT TO MODERATE
RAIN...ASSOCIATED WITH THE LARGER SYNOPTIC SCALE TROUGH AND COMPLEX
SFC LOW PATTERN...IS STEADILY MOVING EWD ACROSS THE MOUNTAINS AND
APPROACHING THE WESTERN PIEDMONT. A TYPICAL WEDGE FRONT HAS BEEN
TAKIN SHAPE THE PAST FEW HOURS AND IS GENERALLY POSITIONED ACROSS
THE ERN FOOTHILLS/WRN PIEDMONT ATTM. THE NEAR-TERM MODELS SUCH AS
THE RAP AND HRRR HAVE A FAIRLY GOOD HANDLE ON THE PATTERN AND
REFLECT OUR CONCEPTUAL IDEA FOR THE REST OF TODAY. LOOK FOR THE RAIN
TO OUR W TO CONTINUE TO MOVE E AND EXPAND ACROSS OUR CWA AS THE DAY
PROGRESSES AS THE LARGER SCALE SYSTEM CONTINUES TO DRIFT E. THE
AFOREMENTIONED RAIN SHOULD FURTHER STRENGTHEN THE LOW LEVEL WEDGE
AND ASSOC BOUNDARY ACROSS WESTERN PIEDMONT...SO TEMPS THERE NOT
EXPECTED TO INCREASE MUCH FROM CURRENT READINGS IN THE U30S TO L40S.
MEANWHILE...THE WARM FRONT FARTHER EAST IS EXPECTED TO GRADUALLY
PUSH INLAND...WITH TEMPS ACROSS OUR E/SE ZONES CLIMBING THROUGH THE
50S AS THE AFTERNOON PROGRESSES. IN BETWEEN THESE TWO BOUNDARIES
ACROSS OUR CNTRL ZONES...TEMPS EXPECTED TO ONLY SLOWLY RISE INTO THE
UPPER 40S TO PERHAPS LOWER 50S.
IN TERMS OF PRECIP...AS ELUDED TO...THE STEADIER LIGHT/MOD PRECIP
ENTERING OUR WRN ZONES WILL CONTINUE TO GRADUALLY SPREAD EWD...SO
THROUGH EARLY AFTERNOON...LOOK FOR RAIN TO BECOME DEVELOP AND BECOME
STEADY ACROSS OUR FAR W/NW ZONES (TRIAD)...WHILE FURTHER E...THE
RAIN WILL BE MORE SCATTERED AND SHOWERY IN NATURE. THEN LATER THIS
AFTERNOON...LOOK FOR THE RAIN TO BECOME STEADY ACROSS MUCH OF OUR
CWA AS THE LOW LEVEL JET AND LARGER SCALE FORCING CURRENTLY TO OUR W
SHIFTS E ACROSS OUR AREA. BY THIS EVENING...THE PRECIP ACROSS OUR
ERN ZONES MAY BECOME MORE CONVECTIVE IN NATURE WITH THE POTENTIAL
FOR A FEW HEAVIER DOWNPOURS AS THE AFOREMENTIONED LOW LEVEL JET AND
LARGER SYNOP SCALE FORCING ENCOUNTERS THE COASTAL BOUNDARY WHICH
SHOULD BE POSITIONED SOMEWHERE ALONG OR TO THE EAST OF I-95 BY THAT
TIME. FORECAST SOUNDINGS HOWEVER SHOW WHAT LITTLE INSTABILITY THERE
IS TO BE ELEVATED...SO IMPACTS W/CONVECTION...AT LEAST AS IT APPEARS
AT THIS POINT...SHOULD BE LIMITED TO SCATTERED HEAVY DOWNPOURS AND
PERHAPS A BRIEF WIND GUST OR TWO BELOW SVR LIMITS. NONETHELESS...
THESE SCATTERED HEAVIER DOWNPOURS MAY RESULT IN BRIEF PERIODS OF LOW
VISIBILITY AND WATER PONDING IN THE TYPICAL POOR DRAINAGE AREAS.
PRECIP EXPECTED TO END ACROSS OUR WRN ZONES BY 8 PM OR SO...AND
ACROSS OUR ERN ZONES SHORTLY AFT MIDNIGHT. -NP
WILL TAPER DOWN POPS WNW TO ESE LATE TONIGHT. MODEL SOUNDINGS SHOW
THE LOW LEVELS REMAINING VERY MOIST AND STABLE... SO EXPECT LOW
CLOUDS AND FOG TO HOLD IN INTO THE OVERNIGHT HOURS... BEFORE FINALLY
LIFTING AND MIXING OUT AS THE SYSTEM CONGEALS INTO A SINGLE LOW JUST
OFF NYC TOWARD SUNRISE SUNDAY. LOWS FROM 33 NW TO 47 SE. -GIH
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM SATURDAY...
AFTER SOME MORNING CLOUDINESS ASSOCIATED WITH THE WEAK SURFACE
TROUGH TRAILING FROM THE COASTAL LOW OFF NYC... THE ENSUING
DOWNSLOPE LOW LEVEL FLOW WILL HELP DRY OUT THE LOWER TROPOSPHERE...
AS INCREASING DEEP LAYER SUBSIDENCE IN THE WAKE OF THE DEPARTING
BROAD TROUGH AXIS HELPS DRY AND STABILIZE THE MID-UPPER LEVELS.
EXPECT PLENTY OF SUNSHINE BY THE AFTERNOON HOURS. THICKNESSES DO
FALL DURING THE DAY (MUCH OF WHICH IS A FUNCTION OF COOLING AT 925-
850 MB WITH A MORE TYPICAL DIURNAL TREND NOTED BELOW 925 MB ALBEIT
WITH SHALLOW MIXING)... BUT THE INCOMING AIR MASS IS MODIFIED AND
SOURCED FROM OUR WSW... AND LATE-DAY THICKNESSES ARE STILL JUST
SLIGHTLY BELOW NORMAL. HIGHS 51-57... CLOSE TO SEASONAL NORMALS.
LOWS 26-33 AS A PORTION OF THE SURFACE HIGH NOSES IN FROM THE SW
CAUSING WINDS TO BECOME LIGHT WITH MOSTLY CLEAR SKIES FACILITATING
RADIATIONAL COOLING. -GIH
&&
.LONG TERM /MONDAY THROUGH FRIDAY NIGHT/...
AS OF 330 AM SATURDAY...
MONDAY AND MONDAY NIGHT: THE LATEST LONG RANGE GUIDANCE CONTINUES TO
INDICATE DRY/BENIGN WEATHER THROUGH THE UPCOMING WORK WEEK...WITH
THE NEXT CHANCE FOR PRECIPITATION PERHAPS NOT UNTIL NEXT WEEKEND.
WEAK HIGH PRESSURE WILL BUILD INTO THE REGION SUN NIGHT/MON IN THE
WAKE OF A COLD FRONTAL PASSAGE...WITH HIGHS ON MONDAY COOLER THAN
SUNDAY...RANGING FROM THE UPPER 40S TO LOWER 50S. LOWS MON NIGHT IN
THE UPPER 20S TO NEAR 30F.
TUESDAY THROUGH WEDNESDAY NIGHT: EXPECT SOME DEGREE OF WARMING ON
TUE VIA SOUTHWEST LOW-LEVEL FLOW AND WARM ADVECTION ASSOC/W A
TIGHTENING MSLP/HEIGHT GRADIENT IN ADVANCE OF A POTENT SHORTWAVE AND
ATTENDANT CLIPPER LOW APPROACHING THE UPPER GREAT LAKES. THE
AFOREMENTIONED SHORTWAVE ENERGY DIGGING SOUTHEAST FROM CANADA TO THE
UPPER GREAT LAKES MON NIGHT/TUE WILL PROGRESS ACROSS THE LOWER GREAT
LAKES/NEW ENGLAND TUE NIGHT AND EARLY WED BEFORE MOVING OFFSHORE NEW
ENGLAND LATE WED. THE GFS/ECMWF GUIDANCE DIFFER ON THE AMPLITUDE OF
THIS SYSTEM...RESULTING IN SOME UNCERTAINTY W/REGARD TO MAX/MIN
TEMPERATURES ACROSS CENTRAL NC TUE/WED. THE GFS SUGGESTS A MORE
AMPLIFIED WAVE WITH STRONGER WARM ADVECTION ON TUE IN ADVANCE OF
IT...AND STRONGER COLD ADVECTION IN THE WAKE OF IT TUE NIGHT/WED...
WHILE THE ECMWF IS WEAKER AND MORE MODERATE WITH TEMPERATURES.
EITHER WAY...DRY CONDITIONS WILL PREVAIL WITH FORCING FOR ASCENT
REMAINING WELL NORTH OF THE REGION. WILL INDICATE HIGHS IN THE
MID/UPPER 50S ON TUE...LOWS IN THE MID 30S TUE NIGHT...AND HIGHS IN
THE LOWER/MID 50S ON WED.
THURSDAY THROUGH FRIDAY NIGHT...EXPECT RISING HEIGHTS ALOFT ALONG
THE EASTERN SEABOARD AND INCREASING MOISTURE ACROSS THE MID-ATLANTIC
AND CAROLINAS IN ASSOC/W A SOUTHERLY RETURN FLOW ON THE WESTERN
PERIPHERY OF OFFSHORE HIGH PRESSURE. UPSTREAM OF THE REGION...
EXPECT TROUGHING ALOFT ACROSS THE CENTRAL CONUS AND ROCKIES...WITH A
STRENGTHENING FRONTAL ZONE EXTENDING FROM THE LOWER MIDWEST
NORTHEAST INTO THE OH VALLEY BY FRI/FRI NIGHT. BOTH THE GFS/ECMWF
AGREE WELL ON THE OVERALL PATTERN...WHICH WOULD SUGGEST A WARMING
TREND ALONG WITH INCREASING CLOUD COVER OVER CENTRAL NC. AT THIS
TIME...EXPECT ANY CHANCE FOR PRECIPITATION TO REMAIN WEST OF THE
MOUNTAINS THROUGH FRIDAY NIGHT. -VINCENT
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 100 PM SATURDAY...
AVIATION CONDITIONS WILL CONTINUE TO DETERIORATE THE REMAINDER OF
THIS AFTERNOON AS THE MAIN RAIN SHIELD TO OUR WEST CONTINUES TO MOVE
EAST. LOOK FOR WIDESPREAD LOW-MVFR AND IFR CONDITIONS (ISOLD POCKETS
OF LIFR) TO DEVELOP ACROSS MOST OF CENTRAL NC BETWEEN NOW AND 21Z.
THE RAIN IS EXPECTED TO END FROM WEST TO EAST BETWEEN 03Z-06Z AS THE
FRONT MOVES THROUGH AND LOW PRESSURE EXITS TO OUR E/NE. HOWEVER IFR
CONDITIONS WITH LOW CLOUDS AND FOG MAY LINGER FOR THE REMAINDER OF
THE NIGHT DUE TO LINGERING LOW LEVEL MOISTURE. AFTER SUNRISE...LOOK
FOR FLIGHT CONDITIONS TO IMPROVE TO VFR AS WINDS BECOME NW AND DRIER
AIR MOVES INTO THE REGION...RESULTING IN CLEARING SKIES.
OTHERWISE...LOW LEVEL WIND SHEAR MAY STILL POSE A THREAT TO AVIATORS
THROUGH THIS EVENING AS SURFACE WINDS FROM THE EAST AT SPEEDS LESS
THAN 12 KTS ARE TOPPED BY 30-40 KT WINDS AROUND 2000 FT AGL FROM THE
SOUTH. HOWEVER...THIS CONCERN HAS BEEN DIMINISHING SOME DURING THE
PAST FEW HOURS AS LOCAL WVPS HAVE BEEN SHOWING SPEEDS AROUND 2K FT
WEAKENING JUST A BIT.
LOOKING BEYOND 18Z SUNDAY...VFR CONDITIONS EXPECTED THROUGH MID-
WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...NP/HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...VINCENT
AVIATION...NP
AREA FORECAST DISCUSSION
NWS NORMAN OK
1100 AM CST SAT DEC 14 2013
.AVIATION...
MFVR CEILINGS WILL SHIFT EAST OF TAF SITES SHORTLY AFTER BEGINNING
OF FORECAST PERIOD WITH VFR CONDITIONS THROUGH REMAINDER OF FORECAST.
GUSTY NORTH WINDS WILL ALSO BEGIN TO DECREASE THIS AFTN AND BECOME
LIGHT AROUND SUNSET. LIGHT WINDS WILL CONTINUE OVERNIGHT WITH A
GRADUAL SHIFT TO THE WEST AND SOUTHWEST. AN INCREASE IN MID/HIGH
CLOUDS EXPECTED AFTER 14Z SUNDAY.
30
&&
.PREV DISCUSSION... /ISSUED 515 AM CST SAT DEC 14 2013/
.DISCUSSION...
AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW.
&&
.AVIATION...
IMPROVING CONDITIONS ARE EXPECTED.
MAINLY MVFR CONDITIONS WITH PATCHES OF IFR CONDITIONS WILL CONTINUE
AT ALL SITES THROUGH AT LEAST 15Z. CONDITIONS WILL IMPROVE WEST TO
EAST 15-20Z. HAVE HIGH CONFIDENCE THAT ALL SITES WILL BE VFR BY 20Z.
GUSTY NORTH TO NORTHWEST WINDS CAN BE EXPECTED AT ALL SITES...
SLOWLY DIMINISHING AFTER 20Z...THEN WEAKENING SIGNIFICANTLY 22-24Z.
MBS
&&
.PREV DISCUSSION... /ISSUED 338 AM CST SAT DEC 14 2013/
DISCUSSION...
WARMER WEATHER OVER THE NEXT SEVERAL DAYS WILL BE THE MAIN WEATHER
STORY.
DENSE FOG ADVISORY ACROSS MAINLY SOUTHERN OKLAHOMA IS IN OKAY
SHAPE...THOUGH VISIBILITIES HAVE BEEN INCREASING RAPIDLY DUE TO
INCREASING LOW LEVEL WINDS AND COLD AIR ADVECTION BEHIND A COLD
FRONT THAT WAS NEAR A WAURIKA TO SEMINOLE LINE AT 330 AM. THE
ADVISORY GOES UNTIL 6 AM THIS MORNING AND MAY BE CANCELLED BEFORE
THEN AS VISIBILITIES SHOULD CONTINUE TO IMPROVE.
KEPT PATCHY DRIZZLE/PATCHY FREEZING DRIZZLE THIS MORNING EAST OF
I-35 AS LATEST RADARS INDICATED LIGHT ECHOES EAST OF WICHITA AND
NEAR TULSA. LATEST HRRR RUNS AND THE RADAR DATA SHOW THAT SOME OF
THIS VERY LIGHT PRECIPITATION MAY AFFECT LOCATIONS EAST OF I-35.
NO PROBLEMS ARE EXPECTED AS THE PRECIPITATION WOULD BE VERY LIGHT
AND MOST LIKELY EVAPORATE ON SURFACES DUE TO THE BRISK NORTH
WINDS.
TODAY WILL BE A BRISK AND COLDER DAY. CLOUDS WILL ERODE WEST TO
EAST WITH THE CLEARING LINE NEAR I-35 AROUND NOON. MODEL GUIDANCE
HIGHS IN THE MID 30S EAST OF I-35 TO THE UPPER 40S ACROSS FAR
WESTERN NORTH TEXAS WERE ACCEPTED.
TONIGHT...CLEAR AND SEASONABLY COLD CONDITIONS WILL OCCUR WITH
LOWS MAINLY IN THE 20S.
SUNDAY WILL BE SUNNY AND WARMER. THINK HIGHS WILL GET IN THE 50S
AREAWIDE...AND PERHAPS ABOVE 60 DEGREES ACROSS PARTS OF WESTERN
OKLAHOMA AND WESTERN NORTH TEXAS.
SUNDAY NIGHT THROUGH THURSDAY...A PERIOD OF WARM AND DRY CAN BE
EXPECTED. TEMPERATURES WILL GENERALLY BE 5 TO 15 DEGREES ABOVE
AVERAGE. HIGHS MAY GET ABOVE 70 DEGREES IN A FEW LOCATIONS.
THURSDAY NIGHT INTO FRIDAY...CONFIDENCE IS GROWING THAT MUCH
COLDER AIR WILL RETURN TO THE AREA WITH AN ARCTIC COLD FRONT.
WINTRY PRECIPITATION MAY RESULT. PRECIPITATION TYPES...
LOCATIONS...AND AMOUNTS REMAIN VERY UNCERTAIN. FOR NOW...KEPT LOW
PRECIPITATION CHANCES ACROSS THE AREA MAINLY ON FRIDAY.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 37 26 58 31 / 0 0 0 0
HOBART OK 43 25 56 27 / 0 0 0 0
WICHITA FALLS TX 46 26 61 30 / 0 0 0 0
GAGE OK 47 21 59 23 / 0 0 0 0
PONCA CITY OK 38 24 56 27 / 0 0 0 0
DURANT OK 40 28 53 33 / 0 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR OKZ043-
047-048-051-052.
TX...NONE.
&&
$$
25/17/17
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1235 PM EST SAT DEC 14 2013
.SYNOPSIS...
A COMPLEX LOW PRESSURE SYSTEM OVER THE LOWER MISSISSIPPI VALLEY
WILL MOVE NORTHEAST TODAY AND INTO THE CENTRAL APPALACHIANS BY
THIS EVENING. THE LOW DEEPENS AND MOVES OFF THE NEW ENGLAND COAST
BY SUNDAY MORNING. HIGH PRESSURE WILL BE OVER THE REGION MONDAY
AND TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM EST SATURDAY...
ADDED MORE SNOW ACROSS THE NORTHWEST TO MATCH UP WITH BAND OF
SNOW LIFTING NORTHWEST. WITH TEMPERATURES NEAR FREEZING...PLACED
SOME FREEZING RAIN ALONG THE SOUTHERN BLUE RIDGE. MODIFIED
TEMPERATURES AND DEW POINTS FOR LATEST OBS AND MODEL TRENDS.
SEE LATEST PNS FOR SNOW AMOUNTS. MORE CHANGES THIS AFTERNOON...
AS OF 925 AM EST SATURDAY...
FIRST BAND OF SNOW EARLY THIS MORNING PRODUCED A LIGHT COATING TO
AROUND ONE INCH ACROSS THE NORTH....WHILE SCATTERED SHOWERS FELL
IN A FEW LOCATIONS. MIX BATCH OF PRECIPITATION ENTERING PORTION
OF CWA THIS MORNING. RECEIVED REPORTS OF SOME SLEET NEAR
INDEPENDENCE IN GRAYSON COUNTY AND ALSO NEAR LYH. HRRR AND
RNKWRFARW SHOWED PRECIPITATION STARTING IN THE SOUTHWEST
SPREADING NORTHEAST ACROSS THE REGION THIS MORNING INTO THIS
AFTERNOON. LOOKING AT TEMPERATURES PROFILES LOOKS LIKE A PERIOD OF
SNOW AND SLEET STILL APPEARS POSSIBLE ESPECIALLY DURING THE ONSET
IN THE SOUTH BEFORE CHANGING TO RAIN. MADE SOME ADJUSTMENTS TO
TEMPERATURES AND DEW POINTS WITH LATEST OBS AND TRENDS. ADDED SOME
FOG FOR THIS MORNING. WITH ACTIVE WEATHER EXPECT MORE CHANGES
LATER THIS MORNING.
AS OF 500 AM EST SATURDAY...
BAND OF SNOW...WELL AHEAD OF THE MAIN AREA OF SYNOPTIC LIFT WAS
MOVING NORTHEAST OUT OF THE COUNTY WARNING AREA AT 5AM. THIS WAS
THE BEGINNING OF THE BREAK IN PRECIPITATION. CLOUD HEIGHTS WERE
STILL LOWERING AND RETURNS ON THE RADAR SHOWED THE PRECIPITATION
THAT WAS AIDING IN THE SATURATION OF THE AIR MASS.
HRRR...LOCAL WRF AND BUFKIT WERE SIMILAR WITH THE TIMING OF THE
MAIN BATCH OF PRECIPITATION...STARTING IN THE SOUTHWEST COUNTY
WARNING AREA BY 9AM AND REACHING THE NORTHEAST COUNTIES BY NOON.
DURATION OF PRECIPITATION WILL BE LIMITED...WITH A WELL DEFINED
DRY SLOT SEEN ON THE NATIONAL RADAR MOSAIC. EXPECT DRY SLOT AND
END OF MUCH OF THE PRECIPITATION TO REACH THE WESTERN COUNTY
WARNING AREA DURING THE MID AFTERNOON...WITH THE PRECIPITATION
ENDING IN THE EAST BY 9PM.
STRONG ISENTROPIC LIFT WILL RESULT IN SOME DECENT PRECIPITATION
RATES. MODELS WERE SHOWING SOME DIABATIC COOLING DURING THE
AFTERNOON NORTH OF ROUTE 460. THIS WILL IMPACT PRECIPITATION TYPE.
EVEN WITH EVAPORATIVE COOLING BRINING THE THERMAL PROFILE BELOW
ZERO...BUFKIT SHOWED A WEAK WARM NOSE FOR MUCH OF THE DAY. HAVE
MORE SLEET IN THE FORECAST THAN EARLIER WHICH WILL LIMIT
ACCUMULATIONS BUT IF PRECIPITATION IS HEAVY ENOUGH...IT WOULD STAY
AS SNOW. BY AFTERNOON TEMPERATURES ALOFT ARE WARM ENOUGH TO SUPPORT
FREEZING RAIN. ALSO BY THEN THE DEPTH OF THE MOISTURE WILL
GRADUALLY BECOME TOO SHALLOW FOR CRYSTAL GROWTH.
STRONG FLOW OFF THE GULF OF MEXICO BRINGS PRECIPITABLE WATER
VALUES BACK ABOVE ONE HALF INCH. HAVE INCREASED AMOUNT OF RAIN IN
THE SOUTHEAST COUNTY WARNING AREA WHERE PRECIPITABLE WATER VALUES
ARE HIGHER. NET RESULT WAS NO CHANGE IN ADVISORY AREA OR TIMING.
NON-DIURNAL TEMPERATURE TREND EXPECTED TODAY AS ONSET OF
PRECIPITATION INITIALLY COOLS SURFACE TEMPERATURES. COLDER AIR
COMES IN TONIGHT AS THE SURFACE LOW DEEPENS OFF THE MID ATLANTIC
COAST AND BRINGS THE WIND AROUND TO THE WEST. UPSLOPE SNOW
SHOWERS WILL PERSIST IN THE FAVORED AREAS OF SOUTHEAST WEST
VIRGINIA.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 345 AM EST SATURDAY...
SHORT TERM PERIOD OF FORECAST WILL BE RATHER UNEVENTFUL AS BROAD
UPPER TROF REMAINS ANCHORED OVER THE UPPER GREAT LAKES. COLD WEST
TO NORTHWEST UPSLOPING WINDS SHOULD MAINTAIN ABUNDANT CLOUD COVER
AND THREAT FOR OCCASIONAL LIGHT SNOW SHOWERS WITH SPOTTY LIGHT
ACCUMULATIONS ACROSS THE WESTERN FLANKS OF THE APPALACHIANS SUNDAY
INTO MONDAY BEFORE FINALLY ABATING BY MONDAY NIGHT AS SURFACE RIDGE
MOVES SOUTHEAST OF THE AREA...ENDING UPSLOPING MOIST FETCH FROM OFF
THE UPPER GREAT LAKES AS SURFACE WINDS BACK INTO THE SOUTHWEST.
TEMPERATURES IN THE UPSLOPE AREAS WILL BE HARD PRESSED TO CLIMB MUCH
ABOVE FREEZING THROUGH THE ENTIRE SHORT TERM PERIOD DUE TO COOLING
FROM FORCED ASCENT AND PERSISTENT CLOUD COVER. HAVE MAINTAINED
PREVIOUS FORECAST THINKING OF GOING A BIT BELOW MOS GUIDANCE DURING
DAYTIME PERIODS...WHICH TYPICALLY OVERESTIMATES THE EXTENT OF
DAYTIME WARMING UNDER THESE CONDITIONS.
ELSEWHERE...ESPECIALLY IN DOWNSLOPING AREAS EAST OF THE BLUE RIDGE
WHERE SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE ENTIRE PERIOD...
DAYTIME HIGHS LIKELY TO CLIMB WELL INTO THE 40S TO LOWER 50S...AND
MOS GUIDANCE GENERALLY ACCEPTED IN THESE AREAS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 335 PM EST FRIDAY...
UNDER ZONAL FLOW AND SOUTHWEST FLOW...THE FORECAST AREA WILL WARM UP
TO NORMAL LEVELS TUESDAY. THE COLD FRONT...WHICH WILL BE MOVING
ACROSS THE OHIO VALLEY TUESDAY...IS A LITTLE SLOWER ON THE 12Z MODEL
RUNS. DESPITE IT BEING SLOWER...STILL LOOKING AT A MOSTLY DRY
FRONTAL PASSAGE AS HIGH PRESSURE BLOCKS MOISTURE RETURNS FROM THE
GULF. MODELS CONTINUE TO ADVERTISE UPSLOPE SNOW SHOWERS FOR WESTERN
GREENBRIER NORTHWARD FOLLOWING THE FRONTAL PASSAGE AND WITH A SHORT
WAVE TRACKING ACROSS THE CENTRAL APPALACHIANS TUESDAY NIGHT...TAPER
TO FLURRIES WEDNESDAY MORNING. A PRESSURE GRADIENT ALSO TIGHTENS
OVER THE AREA TUESDAY NIGHT INTO WEDNESDAY TO BRING WINDY/GUSTY
CONDITIONS TO THE AREA. A SUBSIDENCE INVERSION SHOULD KEEP THE
HIGHER WINDS ABOVE 3 KFT TUESDAY NIGHT. AS THE INVERSION BREAKS AND
CLOUDS ERODE WEDNESDAY...MIXING ACROSS THE ENTIRE FORECAST AREA IS
EXPECTED. WINDS ACROSS THE HIGHER ELEVATIONS MAY REACH WIND ADVISORY
CRITERIA. HIGH PRESSURE BUILDS OVER THE REGION WEDNESDAY NIGHT...
ALLOWING THE WINDS TO SUBSIDE. HIGH PRESSURE WILL THEN MOVE OFF THE
MID ATLANTIC COAST ON FRIDAY. THIS WILL ALLOW THE NEXT SYSTEM TO
APPROACH THE REGION NEXT WEEKEND.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 1235 PM EST SATURDAY...
POOR FLYING CONDITIONS EXPECTED DURING THE PERIOD WITH
WINTERY MIX OF RAIN...FREEZING RAIN...SNOW AND SLEET FALLING
ACROSS THE REGION THIS AFTERNOON INTO TONIGHT. IN
GENERAL...CONDITIONS ARE MVFR WITH LOCALIZED IFR/LIFR IN HEAVY
BANDS OF PRECIPITATION.
AS THE LOW MOVES OFFSHORE...WINDS WILL TURN TO THE WEST. THIS
WILL LEAD TO UPSLOPE IFR TO LIFR CLOUDS AND PRECIPITATION AT
KBLF/KLWB. CEILINGS WILL GRADUALLY LIFT EAST OF THE BLUE
RIDGE...BUT CLOUDS MAY NOT BECOME SCATTERED UNTIL AFTER THE 12Z.
THE UPSLOPE CLOUDS WILL HOLD IN OVER SOUTHEAST WEST VIRGINIA
THROUGH SUNDAY NIGHT.
MEDIUM CONDIFENCE IN CEILINGS AND VISIBILITIES DURING THE
TAF PERIOD. HIGH CONFIDENCE IN WIND DURING THE PERIOD.
HIGH PRESSURE EXPECTED TO BUILD INTO THE REGION FROM THE WEST
SUNDAY NIGHT INTO MONDAY...ALLOWING UPSLOPING CLOUDS TO GRADUALLY
ERODE OVER THE MOUNTAINS...BRINGING A RETURN TO VFR WEATHER WITH
UNRESTRICTED CONDITIONS...EVEN IN THE UPSLOPE AREAS...BY MIDDAY
MONDAY. DRY WEATHER WITH MAINLY VFR WEATHER IS THEN EXPECTED IN
MOST AREAS INTO MID WEEK...WITH PERHAPS THE EXCEPTION OF A PERIOD
OF SOME UPSLOPING CLOUDS WITH MVFR CEILINGS ACROSS THE WESTERN
FLANKS OF THE APPALACHIANS LATER TUESDAY INTO WEDNESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR VAZ018>020-
023-024-034-035.
NC...NONE.
WV...WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR WVZ044-045.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...WERT
LONG TERM...RCS
AVIATION...AMS/WERT/KK
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1010 AM PST Sat Dec 14 2013
.SYNOPSIS...
A series of weak weather systems will clip the Inland Northwest
through Tuesday bringing a chance for light snow showers at times
for areas mainly near the Canadian border and Idaho Panhandle. On
Wednesday into Thursday a stronger system will bring better
chances for rain and snow. Temperatures are expected climb
slightly above normal through Wednesday before falling back to
below normal for the end of next week.
&&
.DISCUSSION...
Radar imagery as of 830 am showed a band of light rain and snow
associated with a warm front moving east into the Idaho Panhandle,
Coeur D`Alene area, Palouse, and Lewiston area. Snow levels have
risen with this front to around 3000 feet over the Idaho Panhandle
and around 5000 feet over the Blue Mountains. Forecast has been
updated based on these latest trends. This area of light
precipitation should only last for a few hours with latest GFS,
NAM, and HRRR showing little in the way of qpf after the warm
front exits this morning. However abundant low level moisture and
southwest winds at 850mb of 15-20 kts will likely result in some
lingering shower activity over the Idaho Panhandle and Northeast
Washington into the afternoon. Also a saturated boundary layer
over much of Eastern Washington and weak low level upslope
southerly winds into Spokane and the Upper Columbia Basin will
likely result in at least patchy fog lingering into the late
morning and afternoon so fog was extended in time in these areas. JW
&&
.AVIATION...
18Z TAFS: A saturated boundary layer over northeast Washington into
the Idaho Panhandle will result in conditions mainly IFR/MVFR
through the afternoon although some improvement is expected. KCOE
may improve to VFR before falling back to IFR conditions tonight.
Downslope southeast winds for KPUW-KLWS should result in CIGS
remaining VFR through 18z Sunday. For tonight into Sunday morning
there is an increased threat for stratus expanding west into Moses
Lake and Wenatchee aided by low level southeast winds. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 36 27 36 29 36 27 / 10 10 10 0 0 10
Coeur d`Alene 38 29 38 31 37 30 / 40 10 10 10 10 10
Pullman 39 30 41 31 40 29 / 60 10 10 0 0 0
Lewiston 41 34 42 33 40 31 / 30 10 10 0 0 0
Colville 36 28 36 28 35 27 / 30 20 10 10 10 20
Sandpoint 36 27 37 29 37 28 / 60 30 20 20 10 30
Kellogg 36 30 38 32 37 31 / 60 20 30 20 20 10
Moses Lake 35 24 38 26 37 25 / 10 10 0 0 0 0
Wenatchee 33 27 38 28 36 27 / 0 10 0 0 0 0
Omak 32 25 34 24 33 23 / 10 10 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
849 AM PST Sat Dec 14 2013
.SYNOPSIS...
A series of weak weather systems will clip the Inland Northwest
through Tuesday bringing a chance for light snow showers at times
for areas mainly near the Canadian border and Idaho Panhandle. On
Wednesday into Thursday a stronger system will bring better
chances for rain and snow. Temperatures are expected climb
slightly above normal through Wednesday before falling back to
below normal for the end of next week.
&&
.DISCUSSION...
Radar imagery as of 830 am showed a band of light rain and snow
associated with a warm front moving east into the Idaho Panhandle,
Coeur D`Alene area, Palouse, and Lewiston area. Snow levels have
risen with this front to around 3000 feet over the Idaho Panhandle
and around 5000 feet over the Blue Mountains. Forecast has been
updated based on these latest trends. This area of light
precipitation should only last for a few hours with latest GFS,
NAM, and HRRR showing little in the way of qpf after the warm
front exits this morning. However abundant low level moisture and
southwest winds at 850mb of 15-20 kts will likely result in some
lingering shower activity over the Idaho Panhandle and Northeast
Washington into the afternoon. Also a saturated boundary layer
over much of Eastern Washington and weak low level upslope
southerly winds into Spokane and the Upper Columbia Basin will
likely result in at least patchy fog lingering into the late
morning and afternoon so fog was extended in time in these areas. JW
&&
.AVIATION...
12Z TAFS: A weak frontal boundary is moving through eastern
Washington this morning and will bring brief rain and snow showers
to the eastern taf sites. This may/should mix up cigs for a short
period of time through 14-15z. Otherwise a saturated boundary layer
will result in conditions mainly IFR/LIFR through the morning. Some
improvement is expected this afternoon...but not much relief is
expected at KGEG-KSFF. KCOE may improve to VFR before falling back
to IFR conditions tonight. KPUW-KLWS mainly VFR but KPUW may see MVFR
conditions briefly this morning. Prevailing VFR conditions for
KMWH-KEAT through early afternoon...then things get quite
complicated as southeast flow should push boundary layer moisture
into this region this afternoon or early this evening. Not much
confidence in the forecast in this area for the last 12 hours...but
the expectation is for stratus development after 03z. /Tobin
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 36 27 36 29 36 27 / 10 10 10 0 0 10
Coeur d`Alene 38 29 38 31 37 30 / 40 10 10 10 10 10
Pullman 39 30 41 31 40 29 / 60 10 10 0 0 0
Lewiston 41 34 42 33 40 31 / 30 10 10 0 0 0
Colville 36 28 36 28 35 27 / 30 20 10 10 10 20
Sandpoint 36 27 37 29 37 28 / 60 30 20 20 10 30
Kellogg 36 30 38 32 37 31 / 60 20 30 20 20 10
Moses Lake 35 24 38 26 37 25 / 10 10 0 0 0 0
Wenatchee 33 27 38 28 36 27 / 0 10 0 0 0 0
Omak 32 25 34 24 33 23 / 10 10 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1010 AM CST SAT DEC 14 2013
.UPDATE...SNOW BANDS HAVE FINALLY DEVELOPED ACROSS FAR SE WI
WHICH IS REFLECTED THE BEST BY THE HRRR AND RAP. THESE MODELS
INDICATE SNOW WILL CONTINUE THROUGH AROUND NOON IN SOUTH-CENTRAL
AND EARLY AFTERNOON FOR THE LAKESHORE COUNTIES.
MID TO LOWER LEVEL FRONTOGENESIS CONTINUES TO CONTRIBUTE TO
FORCING INSTEAD OF MUCH LAKE EFFECT...ALTHOUGH LAKE ENHANCEMENT IS
PROBABLY PLAYING A ROLE...SO KEPT THE LAKE EFFECT SNOW ADVISORY
GOING. RAP AND NAM SOUNDINGS SHOW THE DENDRITE GROWTH ZONE REMAINS
SATURATED THROUGH MOST OF THE AFTERNOON...HOWEVER OMEGA QUICKLY
BECOMES POSITIVE AROUND MIDDAY AS UPPER TROUGH MOVES IN...WHICH
WILL HELP TO DIMINISH SNOW. WINDS WILL THEN TURN NORTHWEST IN THE
EVENING ENDING SNOW CHANCES AS THE SURFACE LOW MOVES INTO OHIO AND
UPPER TROUGH AXIS MOVES ACROSS E WI.
&&
.AVIATION/18Z TAFS/...LAKE EFFECT/ENHANCED SNOW WILL CONTINUE
THROUGH MUCH OF THE DAY...WINDING DOWN WEST TO EAST THIS AFTERNOON.
LATEST RADAR TRENDS SHOW AN OVERALL WEAKENING OF RETURNS...BUT AS
LONG AS THE FLOW REMAINS ONSHORE THERE WILL BE A THREAT OF HEAVIER
BANDS. VISIBILITIES WILL GENERALLY RANGE FROM 1 TO 3 MILES INTO
EARLY AFTERNOON...WITH IMPROVING CONDITIONS AS THE SNOW LETS UP.
COULD SEE SOME BRIEFLY LOWER VISIBILITIES WITHIN HEAVIER SNOW
BANDS. COULD SEE ANOTHER INCH OR SO OF SNOW THROUGH THE REST OF
THE DAY.
MAY SEE A LITTLE SNOW LINGER NORTH IN THE EVENING AND OVERNIGHT AS
THE UPPER TROUGH MOVES THROUGH...BUT OTHERWISE SHOULD BE DRY THEN
THROUGH SUNDAY. MVFR CIGS MAY HANG AROUND THROUGH THE NIGHT AND
INTO SUNDAY...WITH VFR CONDITIONS PROBABLY RETURNING BY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 346 AM CST SAT DEC 14 2013/
SHORT TERM...
TODAY-FORECAST CONFIDENCE HIGH
FRONTOGENESIS IN RIGHT ENTRANCE REGION OF 140 KNOT 250 MB JET HAS
SLOWLY HELPED MOISTEN COLUMN DURING THE NIGHT...BUT SIGNIFICANT
PRECIPITATION HAS BEEN SLOWER TO DEVELOP THAN MOST OF THE MODEL
GUIDANCE SUGGESTED GOING INTO THE EVENT. IR SHOWS CLOUD TOPS
COOLING INTO -40 TO -50C RANGE FROM CENTRAL IOWA INTO SOUTHERN
WISCONSIN. NARROW FRONTOGENESIS BAND FROM KPVB TO JUST SOUTH OF
KMSN TO KMWC HAS PRODUCED LIGHT SNOW THUS FAR MAINLY NEAR THE SHORE.
TMKE SHOWS LIGHT MULTI-BAND LAKE EFFECT SNOW SHOWERS MOVING ONSHORE
IN EASTERLY FLOW REGIME. THIS SHOULD CONTINUE WELL INTO THE
AFTERNOON AND EXPECT COVERAGE TO INCREASE FURTHER AS SEEDING FROM
MID LEVEL FRONTOGENESIS BANDS ENHANCES THE PRECIPITATION. CONSENSUS
OF AVAILABLE MODEL GUIDANCE CONTINUES TO SHOW QPF OF ABOUT 0.25"
NEAR THE SHORE ESPECIALLY NEAR MILWAUKEE COUNTY AREA...WHERE MID
LEVEL FRONTOGENESIS BAND IS SHOWN TO PIVOT OVER THE NEXT 12 HOURS.
THUS 3-5" SNOWFALL SUPPORTING LAKE EFFECT SNOW ADVISORY WITHIN 1-2
COUNTIES OF THE SHORE STILL LOOKS REASONABLE. ELSEWHERE UP TO 1-2"
SEEMS REASONABLE AS NORTHERN BRANCH TROUGH APPROACHES FROM MINNESOTA
WITH ASSOCIATED 70 METER 500 MB HEIGHT FALLS.
UPPER TROUGH MOVES THROUGH IN THE LATE AFTERNOON WITH LOW LEVEL FLOW
TURNING TO THE NORTHWEST RAPIDLY SO EXPECT CUTOFF IN PRECIPITATION
AROUND DARK.
TONIGHT-FORECAST CONFIDENCE HIGH
COLD NORTHWEST FLOW WITH GRADUALLY FALLING HEIGHTS EXPECTED.
CYCLONIC FLOW AND LINGERING BOUNDARY LAYER MOISTURE PROBABLY KEEPS
THINGS OVERCAST MUCH OF THE NIGHT SO NOT MUCH OPPORTUNITY FOR
RADIATION. THIS ESPECIALLY TRUE GIEVN 30 KNOT NORTHWEST FLOW AT 850
MB. SHOULD BE DRY.
SUNDAY THROUGH MONDAY NIGHT...FORECAST CONFIDENCE
IS MEDIUM.
DRY AIR CONTINUES TO SHIFT INTO THE REGION ON SUNDAY...AS WEST
NORTHWEST WINDS REMAIN. 500 MB VORTICITY MAXIMUM PASSES JUST NORTH
OF THE AREA...EXCEPT NAM WHICH CLIPS THE NORTHEAST PORTIONS OF THE
AREA. AREA FORECAST SOUNDINGS SHOWING SOME MID LEVEL CLOUDS MOVING
THROUGH THE REGION...WITH LOW LEVELS DRY. LEFT SUNDAY DRY...WITH
COLD TEMPERATURES CONTINUING PER 925 MB TEMPERATURE FIELDS.
KEPT SUNDAY NIGHT DRY AS WELL...WITH 500 MB VORTICITY MAXIMUM
REMAINING SOUTHWEST OF THE AREA. GFS/ECMWF/CANADIAN MODELS TRY TO
CLIP THE FAR SOUTHWEST COUNTIES WITH LIGHT QPF WITH THIS
FEATURE...BUT FORECAST SOUNDINGS ARE SHOWING ONLY SOME LOW
CLOUDS...WITH THE MID LEVELS DRY. TEMPERATURES WILL CONTINUE TO BE
COLD...WITH LOWS DROPPING INTO THE SINGLE DIGITS ABOVE ZERO.
MAINTAINED POPS FOR MONDAY AND MONDAY NIGHT ACROSS THE AREA. PUSH
OF WARM AIR ADVECTION OCCURS IN THE LOW LEVELS FOR
MONDAY...FOLLOWED BY A STRONG 500 MB VORTICITY MAXIMUM PASSING
THROUGH THE REGION MONDAY NIGHT. AREA FORECAST SOUNDINGS SHOW SOME
SATURATION IN THE AIR COLUMN MONDAY...WITH SOME DIFFERENCES
BETWEEN THE GFS AND NAM. THEY ARE SOMEWHAT DRY MONDAY NIGHT.
TEMPERATURES TRY TO MODERATE SOMEWHAT DURING THIS TIME.
LONG TERM...TUESDAY THROUGH SATURDAY...FORECAST CONFIDENCE IS
MEDIUM.
GFS/ECMWF SHOWING SOME AGREEMENT EARLY IN THE PERIOD...AS THEY
BRING A 500MB VORTICITY MAXIMUM THROUGH THE REGION ON TUESDAY.
AREA FORECAST SOUNDINGS FROM GFS ARE SOMEWHAT DRY...THOUGH DO HAVE
WEAK LOW LEVEL INSTABILITY. KEPT DRY FORECAST FOR NOW. HIGH
PRESSURE AXIS PASSES THROUGH THE REGION TUESDAY NIGHT INTO
WEDNESDAY...CONTINUING THE QUIET WEATHER. WARM AIR ADVECTION THEN
KICKS IN WEDNESDAY NIGHT...BUT AIRMASS IS FAIRLY DRY. TEMPERATURES
ARE STILL BELOW SEASONAL NORMALS.
GFS/ECMWF THEN BRING DEVELOPING LOW PRESSURE FROM THE CENTRAL HIGH
PLAINS TO NORTHERN LOWER MICHIGAN THURSDAY THROUGH THURSDAY
NIGHT...BEFORE HIGH PRESSURE RETURNS FOR FRIDAY INTO SATURDAY.
WARM AIR ADVECTION ON THE FRONT SIDE MAY LEAD TO A MIX OF
PRECIPITATION THURSDAY AFTERNOON AND EVENING...BEFORE COLD FRONT
MOVES THROUGH AND COOLS THINGS OFF. FOR NOW...USED CONSENSUS OF
MODELS FOR POPS AND TEMPERATURES IN THIS PERIOD.
AVIATION/12Z TAFS/...
COMBINATION OF LAKE EFFECT SNOW SHOWERS AND BANDS OF SYNOPTIC SCALE
SNOW SHOULD KEEP IFR CONDITIONS MUCH OF THE DAY ESPECIALLY OVER THE
SOUTHEAST WISCONSIN TAF SITES. ALTHOUGH SNOW HAS BEEN SLOW TO
DEVELOP AT KMSN THERE IS A FRONTOGENESIS BAND JUST SOUTH OF THE
AIRPORT THAT SHOULD EVENTUALLY WORK ITS WAY NORTH AND EXPAND DURING
THE MORNING.
NO BETTER THAN LOWER END MVFR CEILINGS OUTSIDE OF THE SNOW LATE THIS
AFTERNOON AND TONIGHT AS CLOUDS ARE EXPECTED TO LINGER AFTER SNOW
MOVES OUT AND FLOW TURNS FROM EASTERLY TO NORTHWEST.
&&
MARINE...
MODERATE EAST WINDS GENERATE WAVES UP TO 6 FEET THROUGH EARLY
AFTERNOON BEFORE WINDS TURN NORTHWEST. WINDS AND WAVES SUBSIDING
LATE THIS AFTERNOON AND EVENING SO EXPECT BRIEF RESPITE IN SMALL
CRAFT ADVISORY CONDITIONS TONIGHT.
WESTERLY WINDS MAY REACH SMALL CRAFT ADVISORY CRITERIA ON SUNDAY
BEHIND THE DEPARTING SYSTEM.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...LAKE EFFECT SNOW ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ052-
059-060-065-066-071-072.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...SM/DDV
TODAY/TONIGHT AND AVIATION/MARINE...CRAVEN
SUNDAY THROUGH FRIDAY...WOOD