Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/03/13
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
944 PM MST SAT NOV 30 2013
.UPDATE...
ISSUED AT 940 PM MST SAT NOV 30 2013
HAVE ADJUSTED AREAS OF FOG FOR TONIGHT THROUGH SUNDAY WITH FOG
MAINLY IN THE VALLEY BOTTOMS AND ALONG THE SLOPES OF THE WESTERN
MOUNTAINS. SOUNDINGS OVER THE LAST 36HRS AT GJT SHOW THE STRATUS
LAYER NEAR 7500FT SO HAVE ADDED FOG TO THE SLOPES DEFINED BY
7-8KFT. THE NEW NAM IS NOT RECOGNIZING THE BOUNDARY LAYER FOG SO
ITS FORECAST TEMPS ARE TOO HIGH FOR THE WESTERN VALLEY SITES. THE
03Z RAP IS CAPTURING THE FOG LAYER BUT ERODES BY SUNDAY AFTERNOON.
WITH WARM ADVECTION ALOFT RETURNING THEN...THE STRATUS LAYER IS
EXPECTED TO PERSIST.
IN THE BIGGER PICTURE...THE NAM IS STILL PRODUCING ONLY LIGHT SNOW
ACCUMULATIONS MAINLY IN THE ELKHEAD AND ZIRKELS TONIGHT THROUGH
SUNDAY. THE NAM12 IS PRODUCING UP TO 5 INCHES. THIS LOOKS A BIT
HEAVY HANDED WITH LITTLE DYNAMICAL FORCING OR WEAK COOL ADVECTION.
THE DENDRITIC CRYSTAL GROWTH REGION DOES NOT FULLY SATURATE SO
OROGRAPHICS WOULD BE THE MAIN MECHANISM.
MONDAY-MONDAY NIGHT...THE 00Z NAM IS MORE ROBUST AND FAST WITH
THE APPROACHING TROUGH. SIGNIFICANT SNOW STARTS ACROSS THE NORTH
MONDAY NIGHT AND SPREADS ACROSS THE CWA ON TUESDAY. WILL EVALUATE
OVERNIGHT FOR A POTENTIAL WATCH.
&&
.SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 427 PM MST SAT NOV 30 2013
INVERSIONS WHICH FORMED IN THE WAKE OF LAST WEEK/S STORM REMAINED
IN PLACE TODAY. AS A RESULT...LOW CLOUDS AND FOG CONTINUED TO
IMPACT VALLEYS BELOW 6500 FEET ASL AND ADJACENT MOUNTAINS TO
BETWEEN 8000 AND 8500 FEET. DAYTIME WARMING ENHANCED BY CLEAR
SKIES ON THE EDGE OF THE STRATUS FIELD WILL CONTINUE TO ERODE THE
STRATUS THROUGH THE AFTERNOON...BUT EXPECT CLOUDS WILL AGAIN
SPREAD UPVALLEY WITH FOG REFORMING IN RESPONSE TO COOLING
TEMPERATURES OVERNIGHT.
SOME QUESTION AS TO WHETHER THE APPROACHING SHORTWAVE TROUGH IN
THE NORTHWESTERLIES WILL ALLOW FOR MIXING OF LOWER LEVELS LATE
TONIGHT. WAA AHEAD OF THIS FEATURE SUGGESTS OTHERWISE AND SURFACE
PRESSURE GRADIENT WEAK AT BEST. CONSEQUENTLY...WILL LEAVE LOW
CLOUDS AND CONTINUE WITH FORECAST FOR FOG. FOR THE NORTHERN
MOUNTAINS...LIFT AND MOISTURE ASSOCIATED WITH THE SHORTWAVE MAY
BEGIN TO GENERATE SOME LIGHT SNOW AFTER MIDNIGHT.
SNOW WILL INCREASE OVER THE ELKHEAD AND PARK RANGES EARLY SUNDAY
AS THE SHORTWAVE SWEEPS OVER THE AREA. THERE WILL BE A BRIEF
PERIOD OF DYNAMIC LIFT WITH THE WAVES PASSAGE SUNDAY MORNING.
THEREAFTER...FROM SUNDAY AFTERNOON THROUGH SUNDAY NIGHT...
OROGRAPHIC LIFT WILL BECOME THE DOMINANT MECHANISM FOR SNOW AS
STRONG WEST TO WEST-NORTHWEST WINDS FROM 20 TO 30 MPH BUFFET THE
AREA. THE 12Z/SAT BUFR SOUNDING FOR KHDN INDICATED THAT A
SATURATED DENDRITIC GROWTH REGION WILL ENHANCE SNOWFALL SUNDAY
MORNING...BUT QUICKLY DRIES AND RISES WITH TROUGH PASSAGE BY
MIDDAY AS TEMPERATURE ADVECTION SHIFTS FROM WEAKLY COLD AIR
ADVECTIVE...TO NEUTRAL SUNDAY AFTERNOON...THEN BECOMES WARM AIR
ADVECTIVE SUNDAY EVENING. THOUGH WAA WILL LIMIT ACCUMULATIONS
BELIEVE ELKHEADS AND SOME OF THE PARK RANGE COULD SEE AMOUNTS
CLOSER TO NAM GUIDANCE OF 3 TO 6 INCHES SUNDAY AND SUNDAY NIGHT...
BUT MAINLY OVER HIGHER EXPOSED PEAKS.
IT/S DOUBTFUL THAT THIS ACTIVITY WILL HAVE MUCH AFFECT ON THE
VALLEY INVERSIONS DISCUSSED PREVIOUSLY AND THEREFORE WILL
CONTINUE TO FORECAST LOW CLOUDS AND FOG FOR THOSE AREAS.
MEANWHILE...THE SOUTHERN MOUNTAINS MAY SEE SOME MID AND HIGH
CLOUDS BUT ARE UNLIKELY TO GET SNOWFALL.
AS FOR TEMPERATURES...SEE NO REASON TO STRAY FROM PERSISTENCE
FORECAST THROUGH THE NEXT THREE PERIODS. THE ONLY EXCEPTION IS
ACROSS THE NORTH WHERE INCREASED LOW AND MID CLOUDS SHOULD BRING
SLIGHTLY WARMER LOWS SUNDAY NIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 427 PM MST SAT NOV 30 2013
OROGRAPHIC SNOWFALL ALONG THE NORTHERN DIVIDE WILL TAPER OFF ON
MONDAY AS THE FLOW TRANSITIONS FROM NORTHWEST EARLY IN THE DAY TO
WESTERLY BY EVENING. THIS SHIFT IN THE FLOW IS THE RESULT OF THE
NEXT STORM SYSTEM DROPPING INTO THE PACIFIC NORTHWEST THROUGHOUT
THE DAY. AS THIS HAPPENS THE GRADIENT WILL TIGHTEN...MAINLY OVER
THE NORTH. OTHER THAN BREEZES OVER THE HIGHER TERRAIN AND
NORTH...AND A FEW LINGERING SNOW SHOWERS OVER THE NORTHERN
DIVIDE...MONDAY WILL GENERALLY BE A QUIET DAY.
THEN THE BIG CHANGE IN CONDITIONS WILL BEGIN TO TAKE PLACE ON
TUESDAY AS THE NORTHWEST UPPER LOW PRESSURE SYSTEM AND ITS
ASSOCIATED SURFACE COLD FRONT APPROACH FROM THE NORTHWEST. THIS
MUCH ADVERTISED STORM SYSTEM IS STILL ON TRACK TO BRING
SIGNIFICANT WEATHER TO THE FORECAST AREA BEGINNING LATE TUE
THROUGH WED...WITH COLD TEMPERATURES AND THE POTENTIAL FOR
CONTINUED UNSETTLED CONDITIONS THROUGH THE END OF THE LONG TERM
PERIOD.
THE FLOW BECOMES SOUTHWEST MON NIGHT INTO TUE AND STRENGTHENS AS
THE UPPER LOW TRACKS INTO ID. IN ADDITION...THE STRONG SURFACE
COLD FRONT WILL REACH OUR NORTH/NORTHWEST EDGE LATE IN THE
AFTERNOON TO THE EVENING...THEN PROCEED SOUTH/SOUTHEAST OVERNIGHT.
IN THE PRE-FRONTAL ENVIRONMENT SOUTHWEST WINDS WILL BECOME STRONG
ACROSS THE MOUNTAINS EARLY IN THE DAY...THEN WILL MIX INTO THE
VALLEYS BY THE AFTERNOON. THE GFS IS QUITE A BIT FASTER THAN THE
NAM12 AND ECMWF WITH THE TIMING OF THIS FRONT. IT BRINGS THE FRONT
INTO NORTHWEST CO/NORTHEAST UT IN THE MORNING...WHERE IT STALLS
NORTH OF THE TAVAPUTS/FLATTOPS THROUGH THE AFTERNOON/EVENING.
WHILE I MOSTLY DISCOUNTED THE GFS TIMING DUE TO LACK OF AGREEMENT
AND CONTINUITY...IF IT WERE TO VERIFY IT COULD RESULT IN
SIGNIFICANT SNOW OVER THE NORTH THROUGH TUE. GENERALLY FOLLOWING
THE NAM AND ECMWF...POPS GRADUALLY TREND UPWARDS THROUGH TUE OVER
THE NORTH...THEN INCREASE AND SPREAD SOUTH OVERNIGHT. WHILE THE
UPPER LOW CENTER IS PROGGED REMAIN TO OUR NORTH...AT LEAST A
COUPLE OF SHORTWAVES WILL SWING AROUND ITS BASE AND ACROSS OUR
FORECAST AREA. WED PROMISES TO BE THE MOST ACTIVE DAY AS THE FIRST
SHORTWAVE AND AN ASSOCIATED 120KT JET PASS OVERHEAD BRINGING GOOD
DYNAMICS AND UPPER SUPPORT TO A SATURATED AIR MASS. PRECIPITATION
WILL MOSTLY BE SNOW IN THE WAKE OF THE STRONG SURFACE FRONT AND BY
WED EVENING ALL AREAS WILL SEE SNOW IN THE COLD ADVECTION BEHIND
THE SHORTWAVE/COLD FRONT.
ANOTHER SHORTWAVE WILL SWING AROUND THE LOW THU/THU NIGHT BRINGING
EVEN COLDER AIR OVER THE REGION...-32C/500MB AND -20C/700MB. THIS
COLD AIR MASS WILL JUST NOT BE ABLE TO HOLD MUCH MOISTURE...AND
MODELS INDICATE A MARKED DOWNTURN IN POPS. HOWEVER MODELS OFTEN
DRY THINGS OUT TOO FAST. THEREFORE KEPT AT LEAST
CHANCE/MOUNTAINS...SLIGHT CHANCE/VALLEYS THROUGH THE DAY ON THU.
THEN POPS DIMINISH THROUGH FRI AND SAT. HOWEVER COLD CONDITIONS
AND GENERAL TROUGHINESS WILL PERSIST OVER THE REGION THROUGH THE
END OF THE WEEK. SO UNSETTLED CONDITIONS ARE POSSIBLE THROUGH SAT.
FRI AND SAT MORNINGS ARE PROMISING TO BE THE COLDEST SO FAR THIS
SEASON WITH TEMPS AT MANY LOCATIONS DROPPING INTO THE SINGLE
DIGITS OR BELOW ZERO...WITH LOWER TEENS ELSEWHERE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 940 PM MST SAT NOV 30 2013
STRATUS AND LIGHT FOG ARE EXPECTED TO CONTINUE OVERNIGHT...EXPANDING
EASTWARD OVERNIGHT TO INCLUDE CEZ-DRO. THE ONLY EXCEPTION TO THIS
RULE WILL BE ACROSS THE NORTH...WHERE AN UPPER LEVEL DISTURBANCE
MAY WEAKEN INVERSIONS CAUSING CLOUDS TO LIFT WHILE FOG DECREASES
IN COVERAGE AND INTENSITY. MVFR CIGS WILL LINGER IN THE LOWER
VALLEYS BEFORE EXPANDING EAST WHILE PATCHY FOG DEVELOPS. FOG WILL
SPREAD...BECOMING LOCALLY DENSE LATE TONIGHT AND INTO SUNDAY
MORNING RESULTING IN AREAS OF IFR VSBY AND CIGS. AREAS EAST WILL
HAVE VFR CONDITIONS THROUGHOUT THE NEXT 24 HOURS. THE ONLY
EXCEPTION BEING THE NORTHERN COLORADO MOUNTAINS WHERE THE
DISTURBANCE MENTIONED PREVIOUSLY WILL BRING NUMEROUS SNOW SHOWERS
RESULTING IN MOUNTAIN OBSCURATIONS OF THE ELKHEAD AND PARK RANGES
ON SUNDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JOE
SHORT TERM...NL
LONG TERM...EH
AVIATION...NL/JOE
AREA FORECAST DISCUSSION
NWS TAUNTON MA
430 PM EST SUN DEC 1 2013
.SYNOPSIS...
AN OCEAN STORM WILL LIKELY PASS FAR ENOUGH OFFSHORE TO BRING
SCATTERED RAIN SHOWERS MON NIGHT/TUE ACROSS THE COASTAL PLAIN. HIGH
PRESSURE AND RELATIVELY MILD WEATHER WILL PUSH IN WED AND THU. A
STRONG COLD FRONT WILL APPROACH DURING FRIDAY BRINGING A CHANCE FOR
PRECIPITATION...THEN PROGRESSIVELY COLDER AIR WORKS IN NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
425 PM UPDATE...
LATEST SURFACE MAP ALREADY SHOWING THE TRANSFER OF ENERGY FROM A
WEAK LOW PRESSURE IN THE LOWER GREAT LAKES TO A LOW PRESSURE OFF
THE MID ATLANTIC COAST. THIS LOW PRESSURE JUST OFF THE COAST WILL
SUPPLY JUST ENOUGH LIFT TO KEEP SHOWERS GOING ACROSS PORTIONS OF
EASTERN MA AND RI. THE HRRR HAD A GOOD HANDLE ON THESE LIGHT
SHOWERS...AND WAS LEANED ON HEAVILY FOR UPDATING THE FORECAST
THIS AFTERNOON. THE GOOD NEWS IS TEMPERATURES ARE ABOVE
FREEZING...SO NOT EXPECTING ANY MORE FREEZING DRIZZLE OR FREEZING
RAIN.
ISOLATED LOW-TOPPED CONVECTION DEVELOPED NEAR THE ENTRANCE TO
NARRAGANSETT BAY. THE MAIN THREAT WILL BE FOR BRIEF TORRENTIAL
RAINFALL. WE DID HAVE A REPORT FROM SOUTH KINGSTOWN RI OF PEA-
SIZED HAIL...A TESTAMENT TO NEARNESS OF COLDER AIR TO THE GROUND.
LATER TONIGHT...THE WEAK OFFSHORE LOW PRESSURE WILL CONTINUE TO
MOVE INTO THE GULF OF MAINE. THIS SHOULD BRING AN END TO MOST OF
THE PRECIPITATION ACROSS SOUTHERN NEW ENGLAND BEFORE CHANGING
PRECIPITATION TYPES BECOME A CONCERN.
LOW-LEVEL MOISTURE SHOULD LEAD TO AREAS OF FOG TONIGHT...
ESPECIALLY AFTER MIDNIGHT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
SOUTHERN NEW ENGLAND IS IN BETWEEN A PAIR OF LOW PRESSURES MONDAY.
THE FIRST WILL BE A LOW PRESSURE MOVING TOWARD THE MARITIMES...THE
OTHER WILL BE A STRONGER LOW PRESSURE OFF THE MID ATLANTIC COAST.
THIS SHOULD MEAN A SLIGHT CHANCE OF SHOWERS TOWARD THE EAST COAST
OF MA DURING THE MORNING...WITH ANOTHER CHANCE OF SHOWERS ACROSS
RI AND SOUTHEAST MA DEVELOPING FROM THE SOUTH DURING LATE
AFTERNOON INTO MONDAY NIGHT. TIMING AND TEMPERATURES INDICATE RAIN
SHOULD BE THE DOMINANT PRECIPITATION TYPE.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
HIGHLIGHTS...
* SCATTERED SHOWERS POSSIBLE TUE ACROSS COASTAL AREAS
* DRY AND MILDER WED INTO THU WITH SPOTTY SHOWERS POSSIBLE
* COLD FRONT MAY BRING PERIOD OF PRECIPITATION THU NIGHT-FRI...THEN
COLDER TEMPERATURES RETURN NEXT WEEKEND
OVERVIEW...
UPPER LEVEL PATTERN EVOLVES FROM BROAD TROUGHING TO AN EVENTUAL
CUTOFF H5 LOW BUT WELL E OF NEW ENGLAND TUE-WED. MEDIUM RANGE MODELS
CONTINUE TO SIGNAL LONG WAVE TROUGH DIVING INTO THE WESTERN U.S.
WITH TEMPS RUNNING AT LEAST 20 DEGREES BELOW SEASONAL NORMALS ACROSS
THE PLAINS BY LATE WEEK. THIS WILL TRANSLATE TO A BROAD RIDGE
BUILDING OVER THE EAST AS WELL AS A SURGE OF SOMEWHAT MILDER TEMPS.
WITH TWO LARGE CUTOFF LOWS SPINNING ACROSS CANADA...COLD AIR APPEARS
TO MIGRATE S AND E WHILE UPPER RIDGE BUILDS OFFSHORE LATER FRIDAY
INTO NEXT WEEKEND. SO...AFTER BRIEF WARMUP...APPEARS ANOTHER SURGE
OF COLD AIR WILL START TO WORK INTO THE REGION LATER SAT/NEXT
SUN...FOR NOW.
DETAILS...
TUESDAY...BACK EDGE OF PRECIP LINGER ACROSS COASTAL AREAS AS LOW
PRES PASSES WELL SE OF NANTUCKET DURING THE DAY. HAVE KEPT CHANCE
POPS GOING THERE...THOUGH SHOULD BE ENDING FOR MOST AREAS EXCEPT THE
CAPE AND ISLANDS DURING THE DAY. LEFTOVER CLOUDS SHOULD START
TO CLEAR DURING THE AFTERNOON. TEMPS WILL TOP OFF IN THE 40S.
TUESDAY NIGHT-WEDNESDAY...WEAK HIGH PRES RIDGE STEADILY CROSSES THE
REGION DURING THIS TIMEFRAME. EXPECT OVERNIGHT LOWS IN THE MID 20S
WELL INLAND TO THE MID-UPPER 30S ALONG THE IMMEDIATE COAST. ON
WED...CLOUDS WILL BEGIN TO PUSH E DURING THE AFTERNOON. HIGHS WILL
AGAIN BE IN THE 40S.
WEDNESDAY NIGHT...WARM FRONT APPROACHES WHICH MAY BRING SOME LIGHT
RAIN SHOWERS OR POSSIBLY SOME LIGHT FREEZING RAIN ACROSS S NH/N
CENTRAL AND NW MA TO BEGIN EARLY WED NIGHT. LOWS IN THE UPPER 20S TO
UPPER 30S EARLY WILL RISE THROUGH THE OVERNIGHT.
THURSDAY-FRIDAY...COLD FRONT SLOWLY SLIDES THROUGH THE REGION DURING
THU INTO THU NIGHT AS IT RUNS CLOSE TO PARALLEL TO THE W-SW UPPER
FLOW. THE FRONT APPEARS TO STALL THU NIGHT INTO FRIDAY WITH ANOTHER
WAVE OF LOW PRES MOVING ALONG IT. THIS WILL BRING RENEWED CHANCE FOR
PRECIP. LOOKS LIKE IT WILL MAINLY BE IN THE FORM OF RAIN. MAY SEE
BRIEF PERIOD OF FREEZING RAIN LATE THU NIGHT INTO FRI MORNING OVER
HIGHER TERRAIN OF S NH AS TEMPS TRY TO FALL AT OR SLIGHTLY BELOW
FREEZING.
FRIDAY NIGHT-SUNDAY...MODELS TRY TO MOVE ANOTHER SHORT WAVE IN THE
ELONGATED UPPER FLOW THAT MAY TRY TO FLATTEN OUT AS UPPER CUTOFF
LOWS ACROSS CENTRAL AND EASTERN CANADA PUSH SURGE OF COLD AIR INTO
THE REGION. TIMING IS STILL IN QUESTION...SO CONTINUED LOW
CONFIDENCE WITH THIS PORTION OF THE FORECAST. DOES LOOK LIKE PERIOD
OF PRECIP WILL CONTINUE INTO SAT...BUT MORE QUESTIONS AS TO PTYPE
DURING THE FRI NIGHT INTO EARLY SAT TIMEFRAME. FOR NOW...HAVE TENDED
TO DRY THINGS OUT DURING SAT BUT WILL TURN COLDER ESPECIALLY ON
SUNDAY.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH MONDAY NIGHT/...MODERATE CONFIDENCE IN TAFS.
LOW CONFIDENCE IN EXACT TIMING.
THROUGH 00Z...A MIX OF CONDITIONS WILL PERSIST THROUGH HIS
AFTERNOON...RANGING FROM VFR...TO IFR ACROSS THE MONADNOCKS OF
NH...THE CENTRAL WORCESTER HILLS...AND THE HIGHER TERRAIN OF
NORTHERN CT. LOW LEVEL RH IS STILL RATHER HIGH...SO EXPECTING CIGS
TO CRASH FOR BRIEF PERIOD THIS EVENING...ESPECIALLY ACROSS EASTERN
MA...INCLUDING KBOS.
TONIGHT...ONSHORE FLOW WILL ALLOW FOR VFR/MVFR CIGS TO DROP
OVERNIGHT TO LOW END MVFR/IFR. EXPECTING FOG TO DEVELOP AT THE
USUAL LOCATIONS...CAUSING SOME VSBYS RESTRICTIONS. LIGHT OFFSHORE
WINDS SHOULD DEVELOP...AND SHOULD KEEP MORE WIDESPREAD FOG FROM
DEVELOPING ACROSS EASTERN MA AND RI. SHOULD THESE WINDS NOT
DEVELOP AS EXPECTED...MORE WIDESPREAD FOG SHOULD RESULT. IFR
TOWARD THE COAST...WITH VFR FARTHER INLAND.
TOMORROW...CONDITIONS SLOWLY IMPROVE TO VFR ACROSS ALL AREAS.
PATCHY DRIZZLE TO START THE DAY ACROSS EASTERN MA.
MONDAY NIGHT...MAINLY MVFR TO VFR CONDITIONS. LOWER CONDITIONS
MOST LIKELY TOWARD THE COAST WHERE THE BEST CHANCE FOR A RAIN
SHOWER WILL EXIST.
KBOS TAF...MODERATE CONFIDENCE...MAINLY DUE TO TIMING ISSUES. FOG
COULD BE MORE WIDESPREAD IF OFFSHORE WIND DO NOT DEVELOP AS
STRONGLY AS CURRENT EXPECTATIONS. LOWER VSBYS AND CIGS WOULD
RESULT OTHERWISE. CIGS LESS THAN 1000 FEET CLOSE TO TERMINAL NOW.
HAVE HIGHER CONFIDENCE LOWER CIGS WILL IMPACT KBOS THIS EVENING.
ALSO SPED UP TIMING FOR LOWER CIGS TO ARRIVE.
KBDL TAF...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE IN
TIMING.
OUTLOOK...TUESDAY THROUGH FRIDAY...MODERATE CONFIDENCE.
TUESDAY...MAINLY VFR CONDITIONS ACROSS CENTRAL AND WESTERN AREAS.
MVFR CIGS/VSBYS WITH BRIEF IFR CONDITIONS POSSIBLE ALONG COASTAL
AREAS ESPECIALLY THROUGH MIDDAY...THEN SHOULD IMPROVE DURING THE
AFTERNOON. MAINLY VFR TUE NIGHT.
WEDNESDAY...MAINLY VFR DURING THE DAY. MAY SEE MVFR CIGS/VSBYS
DEVELOP FROM W-E WED NIGHT.
WEDNESDAY NIGHT-THURSDAY NIGHT...LOW END VFR CONDITIONS WITH PERIODS
OF MVFR-IFR IN SCT SHOWERS. MAY SEE BRIEF PERIOD OF -FZRA BOTH LATE
WED NIGHT AND THU NIGHT ACROSS HIGHER TERRAIN OF S NH POSSIBLY INTO
N CENTRAL AND NW MA.
FRIDAY...MAINLY MVFR CIGS/VSBYS IN SHOWERS DURING THE DAY. MAY SEE
BRIEF PERIOD OF IFR CONDITIONS FRI NIGHT AS PRECIP BEGINS TO MIX AS
COLDER AIR MOVES IN ACROSS S NH/N MA.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH MONDAY NIGHT/...HIGH CONFIDENCE.
CONDITIONS WILL BE BELOW SMALL CRAFT ADVISORY LEVELS THROUGH THIS
PERIOD. DRIZZLE AND FOG WILL BE THE MAIN CONCERN TONIGHT INTO
MONDAY...WHICH COULD LOWER VISIBILITIES.
OUTLOOK...TUESDAY THROUGH FRIDAY...
TUESDAY...MODERATE TO HIGH CONFIDENCE. OCEAN STORMS PASSES WELL SE
OF NANTUCKET...BUT WILL STILL SEE NE WINDS GUSTING TO 25 KT ACROSS
THE EASTERN OUTER WATERS. SEAS WILL ALSO BUILD...UP TO 5-8 FT MAINLY
OVER THE OUTER WATERS.
WEDNESDAY...WINDS BACK TO NW AND START TO DIMINISH. MAY SEE SOME
GUSTS TO 25 KT. SEAS WILL REMAIN ABOVE SMALL CRAFT CRITERIA...THOUGH
SHOULD SUBSIDE DURING WED NIGHT.
THURSDAY-FRIDAY...EXPECT WINDS BELOW SMALL CRAFT CRITERIA. SEAS MAY
LINGER AROUND 5 FT ON THE OUTER WATERS.
&&
.TIDES/COASTAL FLOODING...
ASTRONOMICAL TIDES ARE QUITE HIGH TUESDAY MORNING...WITH AN 11.9
HIGH TIDE IN BOSTON. FORTUNATELY...IT LOOKS LIKE AN OCEAN STORM
WILL INTENSIFY TOO FAR EAST AND TOO LATE FOR A SIGNIFICANT COASTAL
FLOOD EVENT. HOWEVER...THE POTENTIAL FOR SPLASHOVER AND POCKETS
OF VERY MINOR COASTAL FLOODING ACROSS THE EASTERN MA COAST STILL
EXISTS GIVEN THE HIGH ASTRONOMICAL TIDES. IN ADDITION...MINOR
BEACH EROSION IS ALSO A POSSIBILITY DURING THE TUESDAY HIGH TIDE
CYCLES ALONG THE OUTER CAPE OCEAN SIDE AND THE EAST SHORE OF
NANTUCKET.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BELK/EVT
NEAR TERM...BELK
SHORT TERM...BELK
LONG TERM...EVT
AVIATION...BELK/EVT
MARINE...BELK/EVT
TIDES/COASTAL FLOODING...STAFF
AREA FORECAST DISCUSSION
NWS TAUNTON MA
239 PM EST SUN DEC 1 2013
.SYNOPSIS...
A CLIPPER LOW TODAY WILL BRING A CHANCE OF LIGHT MIXED WINTRY
PRECIPITATION. AN OCEAN STORM WILL LIKELY PASS FAR ENOUGH EAST OF
OUR REGION TO JUST BRING THE RISK FOR A PERIOD OF RAIN SHOWERS MON
NIGHT/TUE...MAINLY ON THE COASTAL PLAIN. RELATIVELY MILD WEATHER
WED/THU WILL BE REPLACED BY MUCH COLDER WEATHER SOMETIME FRI OR
SAT...ALONG WITH THE POTENTIAL FOR A PERIOD OF PRECIPITATION.
&&
.NEAR TERM /THROUGH TONIGHT/...
200 PM UPDATE...
LATEST SURFACE MAP ALREADY SHOWING THE TRANSFER OF ENERGY FROM A
WEAK LOW PRESSURE IN THE LOWER GREAT LAKES TO A LOW PRESSURE OFF
THE MID ATLANTIC COAST. THIS LOW PRESSURE JUST OFF THE COAST WILL
SUPPLY JUST ENOUGH LIFT TO KEEP SHOWERS GOING ACROSS PORTIONS OF
EASTERN MA AND RI. THE HRRR HAD A GOOD HANDLE ON THESE LIGHT
SHOWERS...AND WAS LEANED ON HEAVILY FOR UPDATING THE FORECAST
THIS AFTERNOON. THE GOOD NEWS IS TEMPERATURES ARE ABOVE
FREEZING...SO NOT EXPECTING ANY MORE FREEZING DRIZZLE OR FREEZING
RAIN.
LATER TONIGHT...THE WEAK OFFSHORE LOW PRESSURE WILL CONTINUE TO
MOVE INTO THE GULF OF MAINE. THIS SHOULD BRING AN END TO MOST OF
THE PRECIPITATION ACROSS SOUTHERN NEW ENGLAND BEFORE CHANGING
PRECIPITATION TYPES BECOME A CONCERN.
LOW-LEVEL MOISTURE SHOULD LEAD TO AREAS OF FOG TONIGHT...
ESPECIALLY AFTER MIDNIGHT.
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
SOUTHERN NEW ENGLAND IS IN BETWEEN A PAIR OF LOW PRESSURES MONDAY.
THE FIRST WILL BE A LOW PRESSURE MOVING TOWARD THE MARITIMES...THE
OTHER WILL BE A STRONGER LOW PRESSURE OFF THE MID ATLANTIC COAST.
THIS SHOULD MEAN A SLIGHT CHANCE OF SHOWERS TOWARD THE EAST COAST
OF MA DURING THE MORNING...WITH ANOTHER CHANCE OF SHOWERS ACROSS
RI AND SOUTHEAST MA DEVELOPING FROM THE SOUTH DURING LATE
AFTERNOON INTO MONDAY NIGHT. TIMING AND TEMPERATURES INDICATE RAIN
SHOULD BE THE DOMINANT PRECIPITATION TYPE.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
HIGHLIGHTS...
* PERIOD OF RAIN SHOWERS POSSIBLE MAINLY COASTAL PLAIN TUE
* MILDER WED/THU WITH JUST THE RISK OF A SPOT SHOWER OR TWO
* TURNING COLDER SOMETIME FRI INTO SAT WITH A PERIOD OF
PRECIPITATION POSSIBLE
DETAILS...
TUESDAY...LATEST MODELS ARE IN FAIRLY GOOD AGREEMENT IN LOW
PRESSURE EMERGING OFF THE CAROLINA COAST AND INTENSIFYING INTO A
STRONG OCEAN STORM. IT APPEARS THOUGH THAT THE SYSTEM WILL TRACK
TOO FAR EAST AND INTENSIFY TOO LATE FOR A SIGNIFICANT IMPACT IN
SOUTHERN NEW ENGLAND. THEREFORE...JUST EXPECT A GLANCING BLOW WITH
THE POTENTIAL FOR A PERIOD OF RAIN SHOWERS MAINLY ALONG THE
COASTAL PLAIN. IF SOME OF THE PRECIPITATION WERE TO REACH INTO THE
DISTANT INTERIOR...IT MAY BE COLD ENOUGH FOR A BIT OF SNOW.
HOWEVER...LATEST GUIDANCE SUGGEST THAT THE STEADY PRECIP MAY BE
CONFINED TO THE COASTAL PLAIN...BUT TOO EARLY TO COMPLETELY RULE
OUT THAT POSSIBILITY. HIGHS SHOULD GENERALLY BE IN THE 40S ON
TUESDAY WITH AN ABUNDANCE OF CLOUDS.
WEDNESDAY AND THURSDAY...
MOST OF THIS TIME WILL PROBABLY END UP DRY...BUT A WEAK SHORTWAVE
MOVING THROUGH IN WESTERLY FLOW ALOFT MAY TRIGGER A FEW SPOT
SHOWERS SOMETIME LATE WED OR THU. RISING HEIGHT FIELDS AHEAD OF A
DIGGING UPPER LEVEL TROUGH IN THE CENTRAL U.S. WILL YIELD
RELATIVELY MILD WEATHER. HIGHS SHOULD GENERALLY BE IN THE 40S TO
LOWER 50S.
FRIDAY AND SATURDAY...
A VERY LOW CONFIDENCE FORECAST OVER THIS TIME. A STRONG COLD
FRONT WILL BE APPROACHING THE REGION...AS A COUPLE WAVES OF LOW
PRESSURE RIDE ALONG IT. DEPENDING ON HOW QUICKLY THE FRONT SAGS
SOUTH AND WHERE WE END UP IN RELATION TO THE WAVES OF LOW
PRESSURE...WILL DETERMINE OUR WEATHER. WE DO KNOW THAT IT WILL
EVENTUALLY TURN COLDER...BUT WHEN THAT OCCURS IS HIGHLY UNCERTAIN.
WE ALSO WILL PROBABLY DEAL WITH A PERIOD OF WET WEATHER. ITS ALSO
NOT OUT OF THE QUESTION THAT SOME OF THE AREA ENDS UP WITH A BIT
OF WINTRY PRECIPITATION AT THE END. THIS WOULD OCCUR IF THE
BOUNDARY HANGS UP TO OUR SOUTH AND ANOTHER WAVE OF LOW PRESSURE
DEVELOPS ON IT. AGAIN THOUGH VERY LOW CONFIDENCE ON HOW THINGS
EVOLVE IN THIS TIME PERIOD.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH MONDAY NIGHT/...MODERATE CONFIDENCE IN TAFS.
LOW CONFIDENCE IN EXACT TIMING.
THROUGH 00Z...A MIX OF CONDITIONS WILL PERSIST THROUGH HIS
AFTERNOON...RANGING FROM VFR...TO IFR ACROSS THE MONADNOCKS OF
NH...THE CENTRAL WORCESTER HILLS...AND THE HIGHER TERRAIN OF
NORTHERN CT.
TONIGHT...ONSHORE FLOW WILL ALLOW FOR VFR/MVFR CIGS TO DROP
OVERNIGHT TO LOW END MVFR/IFR. EXPECTING FOG TO DEVELOP AT THE
USUAL LOCATIONS...CAUSING SOME VSBYS RESTRICTIONS. LIGHT OFFSHORE
WINDS SHOULD DEVELOP...AND SHOULD KEEP MORE WIDESPREAD FOG ACROSS
EASTERN MA AND RI. SHOULD THESE WINDS NOT DEVELOP AS EXPECTED...
MORE WIDESPREAD FOG SHOULD DEVELOP. IFR TOWARD THE COAST...WITH
VFR FARTHER INLAND.
TOMORROW...CONDITIONS SLOWLY IMPROVE TO VFR ACROSS ALL AREAS.
PATCHY DRIZZLE TO START THE DAY ACROSS EASTERN MA.
MONDAY NIGHT...MAINLY MVFR TO VFR CONDITIONS. LOWER CONDITIONS
MOST LIKELY TOWARD THE COAST WHERE THE BEST CHANCE FOR A RAIN
SHOWER WILL EXIST.
KBOS TAF...MODERATE CONFIDENCE...MAINLY DUE TO TIMING ISSUES. FOG
COULD BE MORE WIDESPREAD IF OFFSHORE WIND DO NOT DEVELOP AS
STRONGLY AS CURRENT EXPECTATIONS. LOWER VSBYS AND CIGS WOULD
RESULT OTHERWISE.
KBDL TAF...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE IN
TIMING.
OUTLOOK...TUESDAY THROUGH THURSDAY...MODERATE CONFIDENCE
TUESDAY...MAINLY MVFR TO VFR CONDITIONS OVER THIS TIME PERIOD.
LOWER CONDITIONS MOST LIKELY ALONG THE COASTAL PLAIN WHERE THE
BEST CHANCE FOR A PERIOD OF RAIN SHOWER WILL EXIST.
WEDNESDAY AND THURSDAY...MAINLY VFR BUT A PERIOD OF MVFR CONDITIONS
ARE POSSIBLE ESPECIALLY LATER THU OR THU NIGHT.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH MONDAY NIGHT/...HIGH CONFIDENCE.
CONDITIONS WILL BE BELOW SCA...HOWEVER THERE MAY BE AN HOUR OR
TWO WHERE SEAS INCREASE TO 5FT ACROSS THE SOUTHERN WATERS. BECAUSE
OF THE LOW CONFIDENCE LEFT IT OUT FOR NOW. OTHERWISE WINDS WILL
DECREASE THROUGH TONIGHT ALLOWING FOR SEAS TO RELAX. DRIZZLE AND
FOG WILL BE THE MAIN CONCERN TONIGHT AND INTO MONDAY...WHICH
COULD LOWER VISIBILITIES.
OUTLOOK...TUESDAY THROUGH THURSDAY...
TUESDAY...MODERATE TO HIGH CONFIDENCE. OCEAN STORM WILL PASS WELL
EAST OF THE REGION. PRESSURE GRADIENT SHOULD STILL INCREASE ENOUGH
FOR A PERIOD OF NORTHERLY SCA WIND GUSTS AND SCA SEAS ON TUESDAY.
WEDNESDAY AND THURSDAY...MODERATE TO HIGH CONFIDENCE. SOME UPPER
LEVEL RIDGING SHOULD KEEPS WINDS BELOW SCA THRESHOLDS.
HOWEVER...SWELL WILL RESULT IN SCA SEAS AT TIMES ACROSS THE SOUTHERN
AND EASTERN ATLANTIC WATERS.
&&
.TIDES/COASTAL FLOODING...
ASTRONOMICAL TIDES ARE QUITE HIGH TUESDAY MORNING...WITH AN 11.9
HIGH TIDE IN BOSTON. FORTUNATELY...IT LOOKS LIKE THE OCEAN STORM
WILL INTENSIFY TOO FAR EAST AND TOO LATE FOR A SIGNIFICANT COASTAL
FLOOD EVENT. HOWEVER...STILL THE POTENTIAL FOR SPLASH OVER AND
POCKETS OF VERY MINOR COASTAL FLOODING ACROSS THE EASTERN MA COAST
GIVEN THE HIGH ASTRONOMICAL TIDES. IN ADDITION...MINOR BEACH
EROSION IS ALSO A POSSIBILITY DURING THE TUESDAY HIGH TIDE CYCLES
ALONG THE OUTER CAPE OCEAN SIDE AND THE EAST SHORE OF NANTUCKET.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BELK/FRANK
NEAR TERM...BELK
SHORT TERM...BELK
LONG TERM...FRANK
AVIATION...BELK/FRANK
MARINE...BELK/FRANK
TIDES/COASTAL FLOODING...STAFF
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
237 PM EST SUN DEC 1 2013
.DISCUSSION...
CURRENT THROUGH MONDAY...MSAS AND RUC13 SURFACE ANALYSIS STILL
SHOWING THAT A COASTAL TROUGH WAS SITUATED OFF THE VOLUSIA AND NORTH
BREVARD COASTS...AND ON TOP OF THE GULF STREAM. RADAR TRENDS SHOW
THAT THE SHOWERS EMBEDDED IN THE FLOW TO THE EAST OF THE TROUGH
AXIS WERE NOT MAKING IT VERY FAR WEST OF THE TROUGH AXIS WHILE
NORTHERLY WINDS ALONG THE COAST INTERACTING WITH EASTERLY WINDS
JUST OFF THE SURFACE FROM CAPE CANAVERAL SOUTH WERE PRODUCING
PERSISTENT LINES OF MODERATE TO OCCASIONALLY HEAVY RAIN FROM VERO
BEACH SOUTH.
STORM REPORTS INDICATED LOCALIZED AMOUNTS OF 3 TO 4 INCHES OR
MORE IN THE VERO BEACH AREA SINCE DAYBREAK WITH MORE RAIN MOVING
IN OFF THE OCEAN. VISIBLE SATELLITE IMAGES WERE SHOWING SEA FOG
ALONG THE VOLUSIA COUNTY COAST AND NEARSHORE WATERS. A RECENT
REPORT CALLED INTO THE OFFICE FROM PEOPLE ON THE INTRACOASTAL
WATERWAY IN THE PONCE INLET AREA INDICATED VISIBILITIES DOWN TO
LESS THAN HALF A MILE.
THE COASTAL TROUGH WL BEGIN TO LIFT NORTHEAST AFTER MIDNIGHT.
THIS WILL ALLOW THE WINDS TO SHIFT BACK TO THE NORTHWEST LATE
OVERNIGHT AND REMAIN OUT OF THE NORTHWEST AND WEST MONDAY AS THE
TROUGH DEEPENS INTO A LOW OFF THE GEORGIA SOUTH CAROLINA COAST.
MODELS DEPICT A WEAK FRONTAL TROUGH/BOUNDARY ASSOCIATED WITH THE
FORMING LOW MOVING DOWN THE PENINSULA MONDAY AND CLEARING EAST
CENTRAL FLORIDA MONDAY NIGHT. GUIDANCE NOT SHOWING MUCH PRECIP WITH
THE BOUNDARY OR A DRYING TREND WITH THE NORTHWEST FLOW BEHIND THE
DEPARTING BOUNDARY.
LOWS MONDAY MORNING EXPECTED TO BE IN THE MID AND UPPER 50S. THE
NORTHWEST FLOW WILL KEEP MONDAYS HIGHS IN THE LOW AND MIDDLE 70S.
THE RAIN CONFINED TO THE COAST AFTER MIDNIGHT AND OVER THE COASTAL
WATERS MONDAY.
A SECONDARY FRONTAL PSG TUE NIGHT SHOULD ONLY BRING INCRSD
CLOUDS/SPRINKLES. WILL HOLD POPS BELOW 20 PERCENT. TEMPS WILL
BEGIN A VERY SLOW/GRADUAL MODIFICATION TUE.
WED-SAT...(PREVIOUS DISC) LARGE ANTICYCLONE EXPANDS FROM THE
YUCATAN PENINSULA TO SOUTH FLORIDA TO NEAR BERMUDA DURING THIS
PERIOD. MEANWHILE...A SURFACE HIGH OVER THE WESTERN ATLANTIC
REMAINS NEARLY STATIONARY WITH ASSOCIATED RIDGE EXTENDING TO
CENTRAL FLORIDA. RESULTANT PATTERN WILL FAVOR A LIGHT SE/S FLOW
WITH NO LARGE SCALE WX IMPACTS. SOME PERIODS OF SHALLOW/ENHANCED
MOISTURE MAY EVENTUALLY PROMPT A SMALL CHANCE OF MARINE/COASTAL
SHOWERS...BUT PROSPECT TOO ILL-DEFINED AT THIS TIME TO INSERT
MENTIONABLE POPS. MAX TEMPS WILL GRADUALLY CLIMB TO LOWER 80S WITH
MINS LOWER/MID 60S BY THU...CONTINUING INTO THE WEEKEND.
EXCEPTIONS WILL BE ALONG COAST NORTH OF THE CAPE WHERE ONSHORE
FLOW ACROSS COLDER SHELF WATERS WILL MODIFY HIGHS TO UPPER
70S...AND COASTAL AREAS SOUTH OF VERO BEACH WHERE WARMER WATERS
WILL MODIFY LOWS TO THE UPPER 60S/NEAR 70.
&&
.AVIATION...
CURRENT-OVERNIGHT...VFR CEILINGS AND VISIBILITIES SANFORD ORLANDO
KISSIMMEE AND WEST. PREVAILING MVFR WITH TEMPO IFR AND LIFR
CONDITIONS ALONG THE COAST KOMN-JUPITER INLET. SCT-BKN FL010 OR BELOW
06Z-14Z THEN VFR AFTER 15Z AS THE NORTHWEST WINDS CLEARS OUT THE AIR
MASS NORTH TO SOUTH.
&&
.MARINE...
CURRENT THROUGH MONDAY...THE TROUGH OFF VOLUSIA AND NORTH BREVARD
COAST WAS PRODUCING NORTHERLY WINDS OVER THE NEARSHORE...THE
INTRACOASTAL WATERS...THE HALIFAX RIVER IN VOLUSIA AND THE INDIAN
RIVER LAGOON FROM BREVARD TO MARTIN COUNTY. BUOYS AND SURFACE
OBSERVATION ALONG THE COAST FROM SAINT AUGUSTINE TO JUPITER INLET
BACK THIS UP BY RECORDING INDICATING NORTHERLY WINDS IN THE 10 TO 15
KNOT RANGE. SEAS HEIGHTS BEING REPORTED WERE 7 FEET OR LESS.
WINDS START BACKING TO THE NORTHWEST OVERNIGHT AS THE COASTAL TROUGH
BEGINS TO MOVE OFF TO THE NORTHEAST. THE SEA FOG ALONG THE VOLUSIA
AND NORTH BREVARD COAST SHOULD DISSIPATE DURING THE EVENING. THE LOW
CLOUDS AND RAIN ALONG THE COAST FROM SOUTH BREVARD TO JUPITER INLET
WILL MOST LIKELY PERSIST AS LONG AS THE WIND STAYS NORTH AND NORTH
NORTHWEST. ONCE THE WINDS STEADY UP OUT OF THE NORTHWEST THE PRECIP
AT THE COAST AND JUST OFF THE BEACHES WILL END AND BECOME ISOLATED
AWAY FROM THE COAST.
TUE-THU...(PREV DISC) RATHER LIGHT/VARIABLE FLOW TUE THEN SE/S
BELOW 15 KT THROUGH THU AS SURFACE HIGH BUILDS OFFSHORE AND RIDGE
EXTENDS TO CENTRAL PENINSULA. SEAS WILL SUBSIDE TO NEAR 2 FEET
CLOSE TO THE COAST AND 3-4 FEET WITHIN THE GULF STREAM TUE-THU AS
RIDGE LIES OVERHEAD.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 57 73 50 74 / 20 10 0 10
MCO 59 75 53 77 / 10 10 0 10
MLB 60 74 54 74 / 20 10 0 10
VRB 59 76 53 76 / 20 10 0 10
LEE 56 73 51 76 / 10 10 0 10
SFB 58 74 52 76 / 20 10 0 10
ORL 59 74 54 76 / 10 10 0 10
FPR 60 76 53 75 / 20 10 0 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM EST THIS
AFTERNOON FOR WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD
COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS FROM SEBASTIAN
INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE-WATERS FROM
VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM
OFFSHORE.
&&
$$
SHORT TERM...WIMMER
LONG TERM....PENDERGRAST
AREA FORECAST DISCUSSION
NWS MIAMI FL
104 PM EST SUN DEC 1 2013
.AVIATION...
SCATTERED SHOWERS WILL CONTINUE TO IMPACT THE EAST COAST TERMINALS
THROUGH THE LATE AFTERNOON HOURS BEFORE DIMINISHING. THESE WILL BE
CAPABLE OF PRODUCING SUB VFR CIGS/VSBYS PERIODICALLY...ESPECIALLY
IN THE HEAVIER SHOWERS THAT MOVE THROUGH. ANOTHER ROUND OF FOG
AROUND THE APF TERMINAL WILL REMAIN POSSIBLE LATE TONIGHT INTO
MONDAY MORNING AHEAD OF AN APPROACHING FRONTAL BOUNDARY. LIGHT
NORTHWEST WINDS WILL FOLLOW THIS BOUNDARY THROUGH THE DAY TOMORROW
WITH MOSTLY DRY CONDITIONS EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 951 AM EST SUN DEC 1 2013/
UPDATE...
THE SHERIFF OFFICES AND THE OBSERVATIONS OVER THE INTERIOR AND
WEST COAST METRO AREAS OF SOUTH FLORIDA ARE NOW REPORTING
VISIBILITIES TO BE BETWEEN 1 TO 3 MILES IN THE FOG. SO WILL LET
THE DENSE FOG ADVISORY EXPIRED AT 10 AM EDT THIS MORNING FOR THE
INTERIOR AND WEST COAST METRO AREAS.
THE FOG SHOULD CONTINUE TO BURN OFF THROUGH NOON TIME ALLOWING FOR
THE SKIES TO BECOME PARTLY CLOUDY BY THIS AFTERNOON ALONG WITH DRY
WEATHER. SO WILL SHOW A TREND OF CLEARING SKIES ALONG WITH DRY
CONDITIONS FOR THE INTERIOR AND WEST COAST METRO AREAS.
FOR THE EAST COAST METRO AREAS...THERE HAS BEEN SOME ISOLATED
SHOWERS WORKING INTO THIS AREA FROM THE ATLANTIC WATERS. THE
ISOLATED SHOWERS WILL CONTINUE TO WORK INTO THE EAST COAST METRO
AREAS THROUGH THE AFTERNOON HOURS ON THE EASTERLY WIND FLOW. SO
WILL KEEP A SLIGHT CHANCE OF SHOWERS IN PLACE FOR THE EAST COAST
METRO AREAS THROUGH THIS AFTERNOON.
REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES
ARE PLANNED.
UPDATE...54/BNB
PREV DISCUSSION... /ISSUED 642 AM EST SUN DEC 1 2013/
AVIATION...
REDUCED VSBYS IN FOG ARE MAINLY IMPACTING THE APF SITE THIS
MORNING AND INLAND OF THE EAST COAST TERMINALS. THIS SHOULD BURN
OFF BY OR BETWEEN 8-9AM WITH VFR CONDITIONS RETURNING. THE BEST
CHANCE OF SHOWERS WILL BE ALONG THE EAST COAST TODAY...WHICH WILL
BE CAPABLE OF PRODUCING PERIODS OF REDUCED CIGS/VSBYS THROUGH THE
DAY. WINDS WILL REMAIN OUT OF THE NORTHEAST AND INCREASE TO AROUND
10 KT THROUGH THE LATE MORNING AND AFTERNOON HOURS. ALTHOUGH
CONFIDENCE REMAINS TOO LOW...WINDS COULD SHIFT TO THE WNW AT APF
DUE A GULF COAST SEA BREEZE THROUGH THE AFTERNOON PERIOD. WILL
MONITOR THIS AND UPDATE IF NEEDED.
PREV DISCUSSION... /ISSUED 319 AM EST SUN DEC 1 2013/
DISCUSSION...
HIGH PRESSURE TO THE NORTH CONTINUES TO BRING NORTHEASTERLY FLOW
TO SOUTH FLORIDA. HOWEVER, THE HIGH WILL BEGIN TO WEAKEN TODAY,
ALLOWING THE WINDS TO BECOME LIGHTER. THERE IS STILL A FEW SHOWERS
OVER THE ATLANTIC WATERS. CURRENTLY, THEY ARE NOT IMPACTING THE
CWA, BUT STILL HAVE A SLIGHT CHANCE IN THE FORECAST. THE HRRR DOES
SHOW SOME ISOLATED SHOWERS OVER THE ATLANTIC COAST METRO AREAS
THIS AFTERNOON, SO BROUGHT SLIGHT CHANCE POPS SOMEWHAT MORE WEST.
MODELS STILL SHOWING A VERY WEAK FRONT PUSHING SOUTH THROUGH SOUTH
FLORIDA TOMORROW, BUT LOOKS BARELY DISCERNIBLE IN THE MODELS. GFS
HAS HIGH PRESSURE BUILDING OVER THE FLORIDA PENINSULA BY 00Z
TUESDAY WITH NO PRECIPITATION AT ALL. THE ECMWF IS SIMILAR, BUT
ABOUT 6 HOURS SLOWER WITH MORE BROAD WEAK HIGH PRESSURE BUILDING.
EITHER WAY. THE BEST EVIDENCE OF THIS FRONT WILL LIKELY BE A WEAK
WINDS SHIFT TOMORROW. BUT, LEFT A SLIGHT CHANCE OF SHOWERS ACROSS
THE CWA FOR THE AFTERNOON HOURS. BUT, GIVEN CURRENT MODEL RUNS,
COULD DEFINITELY SEE THIS BEING PULLED OUT OF THE FORECAST LATER
TODAY.
AFTER TOMORROW, IT IS HIGH PRESSURE FOR THE REMAINDER OF THE
FORECAST PERIOD. THE AIR MASS WILL WARM VERY SLIGHTLY THROUGH THE
WEEK, WITH PERHAPS A FEW LIGHT COASTAL SHOWERS POSSIBLE,
ESPECIALLY IN THE OVERNIGHT HOURS.
AVIATION...
MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE EARLY
MORNING HOURS. HOWEVER...AN AREA OF CLOUDINESS AND EMBEDDED
SHOWERS IS MOVING WESTWARD INTO THE LOCAL ATLANTIC WATERS AND A FEW
SHOWERS COULD IMPACT THE EAST COAST TERMINALS FROM TIME TO TIME.
ONLY PASSING SHOWERS EXPECTED BUT WILL AMEND IF ANY VIS/CEILING
RESTRICTIONS OCCUR BUT NOT EXPECTED. WINDS ACROSS THE EAST COAST
TERMINALS STARTING TO BECOME LIGHT AND VARIABLE WITH AN OFF SHORE
DRAINAGE FLOW BEGINNING.
MARINE...
HIGH PRESSURE TO THE NORTH WILL WEAKEN TODAY, BUT STILL KEEP
EASTERLY FLOW OVER THE COASTAL WATERS. THE WEAKER WINDS WILL
RESULT IN SEAS CONTINUING TO SUBSIDE TODAY. GIVEN THIS ALL
ADVISORIES AND CAUTION STATEMENTS HAVE BEEN CANCELLED. THERE IS A
SLIGHT CHANCE OF SHOWERS OVER THE NEXT COUPLE OF DAYS AS A VERY
WEAK COLD FRONT SLIDES ACROSS THE AREA TOMORROW.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 62 78 58 79 / 10 - - -
FORT LAUDERDALE 63 78 62 79 / 10 - - -
MIAMI 64 80 62 79 / 10 - - -
NAPLES 60 75 59 78 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...54/BNB
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
951 AM EST SUN DEC 1 2013
.UPDATE...
THE SHERIFF OFFICES AND THE OBSERVATIONS OVER THE INTERIOR AND
WEST COAST METRO AREAS OF SOUTH FLORIDA ARE NOW REPORTING
VISIBILITIES TO BE BETWEEN 1 TO 3 MILES IN THE FOG. SO WILL LET
THE DENSE FOG ADVISORY EXPIRED AT 10 AM EDT THIS MORNING FOR THE
INTERIOR AND WEST COAST METRO AREAS.
THE FOG SHOULD CONTINUE TO BURN OFF THROUGH NOON TIME ALLOWING FOR
THE SKIES TO BECOME PARTLY CLOUDY BY THIS AFTERNOON ALONG WITH DRY
WEATHER. SO WILL SHOW A TREND OF CLEARING SKIES ALONG WITH DRY
CONDITIONS FOR THE INTERIOR AND WEST COAST METRO AREAS.
FOR THE EAST COAST METRO AREAS...THERE HAS BEEN SOME ISOLATED
SHOWERS WORKING INTO THIS AREA FROM THE ATLANTIC WATERS. THE
ISOLATED SHOWERS WILL CONTINUE TO WORK INTO THE EAST COAST METRO
AREAS THROUGH THE AFTERNOON HOURS ON THE EASTERLY WIND FLOW. SO
WILL KEEP A SLIGHT CHANCE OF SHOWERS IN PLACE FOR THE EAST COAST
METRO AREAS THROUGH THIS AFTERNOON.
REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES
ARE PLANNED.
&&
.UPDATE...54/BNB
.PREV DISCUSSION... /ISSUED 642 AM EST SUN DEC 1 2013/
AVIATION...
REDUCED VSBYS IN FOG ARE MAINLY IMPACTING THE APF SITE THIS
MORNING AND INLAND OF THE EAST COAST TERMINALS. THIS SHOULD BURN
OFF BY OR BETWEEN 8-9AM WITH VFR CONDITIONS RETURNING. THE BEST
CHANCE OF SHOWERS WILL BE ALONG THE EAST COAST TODAY...WHICH WILL
BE CAPABLE OF PRODUCING PERIODS OF REDUCED CIGS/VSBYS THROUGH THE
DAY. WINDS WILL REMAIN OUT OF THE NORTHEAST AND INCREASE TO AROUND
10 KT THROUGH THE LATE MORNING AND AFTERNOON HOURS. ALTHOUGH
CONFIDENCE REMAINS TOO LOW...WINDS COULD SHIFT TO THE WNW AT APF
DUE A GULF COAST SEA BREEZE THROUGH THE AFTERNOON PERIOD. WILL
MONITOR THIS AND UPDATE IF NEEDED.
&&
PREV DISCUSSION... /ISSUED 319 AM EST SUN DEC 1 2013/
DISCUSSION...
HIGH PRESSURE TO THE NORTH CONTINUES TO BRING NORTHEASTERLY FLOW
TO SOUTH FLORIDA. HOWEVER, THE HIGH WILL BEGIN TO WEAKEN TODAY,
ALLOWING THE WINDS TO BECOME LIGHTER. THERE IS STILL A FEW SHOWERS
OVER THE ATLANTIC WATERS. CURRENTLY, THEY ARE NOT IMPACTING THE
CWA, BUT STILL HAVE A SLIGHT CHANCE IN THE FORECAST. THE HRRR DOES
SHOW SOME ISOLATED SHOWERS OVER THE ATLANTIC COAST METRO AREAS
THIS AFTERNOON, SO BROUGHT SLIGHT CHANCE POPS SOMEWHAT MORE WEST.
MODELS STILL SHOWING A VERY WEAK FRONT PUSHING SOUTH THROUGH SOUTH
FLORIDA TOMORROW, BUT LOOKS BARELY DISCERNIBLE IN THE MODELS. GFS
HAS HIGH PRESSURE BUILDING OVER THE FLORIDA PENINSULA BY 00Z
TUESDAY WITH NO PRECIPITATION AT ALL. THE ECMWF IS SIMILAR, BUT
ABOUT 6 HOURS SLOWER WITH MORE BROAD WEAK HIGH PRESSURE BUILDING.
EITHER WAY. THE BEST EVIDENCE OF THIS FRONT WILL LIKELY BE A WEAK
WINDS SHIFT TOMORROW. BUT, LEFT A SLIGHT CHANCE OF SHOWERS ACROSS
THE CWA FOR THE AFTERNOON HOURS. BUT, GIVEN CURRENT MODEL RUNS,
COULD DEFINITELY SEE THIS BEING PULLED OUT OF THE FORECAST LATER
TODAY.
AFTER TOMORROW, IT IS HIGH PRESSURE FOR THE REMAINDER OF THE
FORECAST PERIOD. THE AIR MASS WILL WARM VERY SLIGHTLY THROUGH THE
WEEK, WITH PERHAPS A FEW LIGHT COASTAL SHOWERS POSSIBLE,
ESPECIALLY IN THE OVERNIGHT HOURS.
AVIATION...
MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE EARLY
MORNING HOURS. HOWEVER...AN AREA OF CLOUDINESS AND EMBEDDED
SHOWERS IS MOVING WESTWARD INTO THE LOCAL ATLANTIC WATERS AND A FEW
SHOWERS COULD IMPACT THE EAST COAST TERMINALS FROM TIME TO TIME.
ONLY PASSING SHOWERS EXPECTED BUT WILL AMEND IF ANY VIS/CEILING
RESTRICTIONS OCCUR BUT NOT EXPECTED. WINDS ACROSS THE EAST COAST
TERMINALS STARTING TO BECOME LIGHT AND VARIABLE WITH AN OFF SHORE
DRAINAGE FLOW BEGINNING.
MARINE...
HIGH PRESSURE TO THE NORTH WILL WEAKEN TODAY, BUT STILL KEEP
EASTERLY FLOW OVER THE COASTAL WATERS. THE WEAKER WINDS WILL
RESULT IN SEAS CONTINUING TO SUBSIDE TODAY. GIVEN THIS ALL
ADVISORIES AND CAUTION STATEMENTS HAVE BEEN CANCELLED. THERE IS A
SLIGHT CHANCE OF SHOWERS OVER THE NEXT COUPLE OF DAYS AS A VERY
WEAK COLD FRONT SLIDES ACROSS THE AREA TOMORROW.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 79 63 77 61 / 20 10 10 -
FORT LAUDERDALE 79 64 77 63 / 20 10 10 -
MIAMI 80 65 78 63 / 20 10 10 -
NAPLES 77 63 75 62 / - - 10 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR COASTAL
COLLIER-GLADES-HENDRY-INLAND BROWARD-INLAND COLLIER-INLAND
PALM BEACH.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...54/BNB
AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS MIAMI FL
642 AM EST SUN DEC 1 2013
.AVIATION...
REDUCED VSBYS IN FOG ARE MAINLY IMPACTING THE APF SITE THIS
MORNING AND INLAND OF THE EAST COAST TERMINALS. THIS SHOULD BURN
OFF BY OR BETWEEN 8-9AM WITH VFR CONDITIONS RETURNING. THE BEST
CHANCE OF SHOWERS WILL BE ALONG THE EAST COAST TODAY...WHICH WILL
BE CAPABLE OF PRODUCING PERIODS OF REDUCED CIGS/VSBYS THROUGH THE
DAY. WINDS WILL REMAIN OUT OF THE NORTHEAST AND INCREASE TO AROUND
10 KT THROUGH THE LATE MORNING AND AFTERNOON HOURS. ALTHOUGH
CONFIDENCE REMAINS TOO LOW...WINDS COULD SHIFT TO THE WNW AT APF
DUE A GULF COAST SEA BREEZE THROUGH THE AFTERNOON PERIOD. WILL
MONITOR THIS AND UPDATE IF NEEDED.
&&
.PREV DISCUSSION... /ISSUED 319 AM EST SUN DEC 1 2013/
DISCUSSION...
HIGH PRESSURE TO THE NORTH CONTINUES TO BRING NORTHEASTERLY FLOW
TO SOUTH FLORIDA. HOWEVER, THE HIGH WILL BEGIN TO WEAKEN TODAY,
ALLOWING THE WINDS TO BECOME LIGHTER. THERE IS STILL A FEW SHOWERS
OVER THE ATLANTIC WATERS. CURRENTLY, THEY ARE NOT IMPACTING THE
CWA, BUT STILL HAVE A SLIGHT CHANCE IN THE FORECAST. THE HRRR DOES
SHOW SOME ISOLATED SHOWERS OVER THE ATLANTIC COAST METRO AREAS
THIS AFTERNOON, SO BROUGHT SLIGHT CHANCE POPS SOMEWHAT MORE WEST.
MODELS STILL SHOWING A VERY WEAK FRONT PUSHING SOUTH THROUGH SOUTH
FLORIDA TOMORROW, BUT LOOKS BARELY DISCERNIBLE IN THE MODELS. GFS
HAS HIGH PRESSURE BUILDING OVER THE FLORIDA PENINSULA BY 00Z
TUESDAY WITH NO PRECIPITATION AT ALL. THE ECMWF IS SIMILAR, BUT
ABOUT 6 HOURS SLOWER WITH MORE BROAD WEAK HIGH PRESSURE BUILDING.
EITHER WAY. THE BEST EVIDENCE OF THIS FRONT WILL LIKELY BE A WEAK
WINDS SHIFT TOMORROW. BUT, LEFT A SLIGHT CHANCE OF SHOWERS ACROSS
THE CWA FOR THE AFTERNOON HOURS. BUT, GIVEN CURRENT MODEL RUNS,
COULD DEFINITELY SEE THIS BEING PULLED OUT OF THE FORECAST LATER
TODAY.
AFTER TOMORROW, IT IS HIGH PRESSURE FOR THE REMAINDER OF THE
FORECAST PERIOD. THE AIR MASS WILL WARM VERY SLIGHTLY THROUGH THE
WEEK, WITH PERHAPS A FEW LIGHT COASTAL SHOWERS POSSIBLE,
ESPECIALLY IN THE OVERNIGHT HOURS.
AVIATION...
MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE EARLY
MORNING HOURS. HOWEVER...AN AREA OF CLOUDINESS AND EMBEDDED
SHOWERS IS MOVING WESTWARD INTO THE LOCAL ATLANTIC WATERS AND A FEW
SHOWERS COULD IMPACT THE EAST COAST TERMINALS FROM TIME TO TIME.
ONLY PASSING SHOWERS EXPECTED BUT WILL AMEND IF ANY VIS/CEILING
RESTRICTIONS OCCUR BUT NOT EXPECTED. WINDS ACROSS THE EAST COAST
TERMINALS STARTING TO BECOME LIGHT AND VARIABLE WITH AN OFF SHORE
DRAINAGE FLOW BEGINNING.
MARINE...
HIGH PRESSURE TO THE NORTH WILL WEAKEN TODAY, BUT STILL KEEP
EASTERLY FLOW OVER THE COASTAL WATERS. THE WEAKER WINDS WILL
RESULT IN SEAS CONTINUING TO SUBSIDE TODAY. GIVEN THIS ALL
ADVISORIES AND CAUTION STATEMENTS HAVE BEEN CANCELLED. THERE IS A
SLIGHT CHANCE OF SHOWERS OVER THE NEXT COUPLE OF DAYS AS A VERY
WEAK COLD FRONT SLIDES ACROSS THE AREA TOMORROW.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 80 62 78 61 / 20 10 10 -
FORT LAUDERDALE 80 64 78 63 / 20 10 10 -
MIAMI 80 64 79 63 / 20 10 10 -
NAPLES 78 63 76 62 / - - 10 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR GLADES-HENDRY-
INLAND BROWARD-INLAND COLLIER-INLAND PALM BEACH.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...54/BNB
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS MIAMI FL
319 AM EST SUN DEC 1 2013
DISCUSSION...
HIGH PRESSURE TO THE NORTH CONTINUES TO BRING NORTHEASTERLY FLOW
TO SOUTH FLORIDA. HOWEVER, THE HIGH WILL BEGIN TO WEAKEN TODAY,
ALLOWING THE WINDS TO BECOME LIGHTER. THERE IS STILL A FEW SHOWERS
OVER THE ATLANTIC WATERS. CURRENTLY, THEY ARE NOT IMPACTING THE
CWA, BUT STILL HAVE A SLIGHT CHANCE IN THE FORECAST. THE HRRR DOES
SHOW SOME ISOLATED SHOWERS OVER THE ATLANTIC COAST METRO AREAS
THIS AFTERNOON, SO BROUGHT SLIGHT CHANCE POPS SOMEWHAT MORE WEST.
MODELS STILL SHOWING A VERY WEAK FRONT PUSHING SOUTH THROUGH SOUTH
FLORIDA TOMORROW, BUT LOOKS BARELY DISCERNIBLE IN THE MODELS. GFS
HAS HIGH PRESSURE BUILDING OVER THE FLORIDA PENINSULA BY 00Z
TUESDAY WITH NO PRECIPITATION AT ALL. THE ECMWF IS SIMILAR, BUT
ABOUT 6 HOURS SLOWER WITH MORE BROAD WEAK HIGH PRESSURE BUILDING.
EITHER WAY. THE BEST EVIDENCE OF THIS FRONT WILL LIKELY BE A WEAK
WINDS SHIFT TOMORROW. BUT, LEFT A SLIGHT CHANCE OF SHOWERS ACROSS
THE CWA FOR THE AFTERNOON HOURS. BUT, GIVEN CURRENT MODEL RUNS,
COULD DEFINITELY SEE THIS BEING PULLED OUT OF THE FORECAST LATER
TODAY.
AFTER TOMORROW, IT IS HIGH PRESSURE FOR THE REMAINDER OF THE
FORECAST PERIOD. THE AIR MASS WILL WARM VERY SLIGHTLY THROUGH THE
WEEK, WITH PERHAPS A FEW LIGHT COASTAL SHOWERS POSSIBLE,
ESPECIALLY IN THE OVERNIGHT HOURS.
AVIATION...
MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE EARLY
MORNING HOURS. HOWEVER...AN AREA OF CLOUDINESS AND EMBEDDED
SHOWERS IS MOVING WESTWARD INTO THE LOCAL ATLANTIC WATERS AND A FEW
SHOWERS COULD IMPACT THE EAST COAST TERMINALS FROM TIME TO TIME.
ONLY PASSING SHOWERS EXPECTED BUT WILL AMEND IF ANY VIS/CEILING
RESTRICTIONS OCCUR BUT NOT EXPECTED. WINDS ACROSS THE EAST COAST
TERMINALS STARTING TO BECOME LIGHT AND VARIABLE WITH AN OFF SHORE
DRAINAGE FLOW BEGINNING.
MARINE...
HIGH PRESSURE TO THE NORTH WILL WEAKEN TODAY, BUT STILL KEEP
EASTERLY FLOW OVER THE COASTAL WATERS. THE WEAKER WINDS WILL
RESULT IN SEAS CONTINUING TO SUBSIDE TODAY. GIVEN THIS ALL
ADVISORIES AND CAUTION STATEMENTS HAVE BEEN CANCELLED. THERE IS A
SLIGHT CHANCE OF SHOWERS OVER THE NEXT COUPLE OF DAYS AS A VERY
WEAK COLD FRONT SLIDES ACROSS THE AREA TOMORROW.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 80 62 78 61 / 20 10 10 -
FORT LAUDERDALE 80 64 78 63 / 20 10 10 -
MIAMI 80 64 79 63 / 20 10 10 -
NAPLES 78 63 76 62 / - - 10 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
315 AM EST SUN DEC 1 2013
.DISCUSSION...
HIGH PRESSURE TO THE NORTH CONTINUES TO BRING EAST TO
NORTHEASTERLY FLOW TO SOUTH FLORIDA. HOWEVER, THE HIGH WILL BEGIN
TO WEAKEN TODAY, ALLOWING THE WINDS TO BECOME LIGHTER. THERE IS
STILL A FEW SHOWERS OVER THE ATLANTIC WATERS. CURRENTLY, THEY ARE
NOT IMPACTING THE CWA, BUT STILL HAVE A SLIGHT CHANCE IN THE
FORECAST. THE HRRR DOES SHOW SOME ISOLATED SHOWERS OVER THE
ATLANTIC COAST METRO AREAS THIS AFTERNOON, SO BROUGHT SLIGHT
CHANCE POPS SOMEWHAT MORE WEST.
MODELS STILL SHOWING A VERY WEAK FRONT PUSHING SOUTH THROUGH SOUTH
FLORIDA TOMORROW, BUT LOOKS BARELY DISCERNIBLE IN THE MODELS. GFS
HAS HIGH PRESSURE BUILDING OVER THE FLORIDA PENINSULA BY 00Z
TUESDAY WITH NO PRECIPITATION AT ALL. THE ECMWF IS SIMILAR, BUT
ABOUT 6 HOURS SLOWER WITH MORE BROAD WEAK HIGH PRESSURE BUILDING.
EITHER WAY. THE BEST EVIDENCE OF THIS FRONT WILL LIKELY BE A WEAK
WINDS SHIFT TOMORROW. BUT, LEFT A SLIGHT CHANCE OF SHOWERS ACROSS
THE CWA FOR THE AFTERNOON HOURS. BUT, GIVEN CURRENT MODEL RUNS,
COULD DEFINITELY SEE THIS BEING PULLED OUT OF THE FORECAST LATER
TODAY.
AFTER TOMORROW, IT IS HIGH PRESSURE FOR THE REMAINDER OF THE
FORECAST PERIOD. THE AIR MASS WILL WARM VERY SLIGHTLY THROUGH THE
WEEK, WITH PERHAPS A FEW LIGHT COASTAL SHOWERS POSSIBLE,
ESPECIALLY IN THE OVERNIGHT HOURS.
&&
.AVIATION...
MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE EARLY
MORNING HOURS. HOWEVER...AN AREA OF CLOUDINESS AND EMBEDDED
SHOWERS IS MOVING WESTWARD INTO THE LOCAL ATLANTIC WATERS AND A FEW
SHOWERS COULD IMPACT THE EAST COAST TERMINALS FROM TIME TO TIME.
ONLY PASSING SHOWERS EXPECTED BUT WILL AMEND IF ANY VIS/CEILING
RESTRICTIONS OCCUR BUT NOT EXPECTED. WINDS ACROSS THE EAST COAST
TERMINALS STARTING TO BECOME LIGHT AND VARIABLE WITH AN OFF SHORE
DRAINAGE FLOW BEGINNING.
&&
.MARINE...
HIGH PRESSURE TO THE NORTH WILL WEAKEN TODAY, BUT STILL KEEP
EASTERLY FLOW OVER THE COASTAL WATERS. THE WEAKER WINDS WILL
RESULT IN SEAS CONTINUING TO SUBSIDE TODAY. GIVEN THIS ALL
ADVISORIES AND CAUTION STATEMENTS HAVE BEEN CANCELLED. THERE IS A
SLIGHT CHANCE OF SHOWERS OVER THE NEXT COUPLE OF DAYS AS A VERY
WEAK COLD FRONT SLIDES ACROSS THE AREA TOMORROW.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 80 62 78 61 / 20 10 10 -
FORT LAUDERDALE 80 64 78 63 / 20 10 10 -
MIAMI 80 64 79 63 / 20 10 10 -
NAPLES 78 63 76 62 / - - 10 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
214 PM EST SUN DEC 1 2013
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
LATEST SURFACE ANALYSIS OVER THE SOUTHEAST UNITED STATES SHOWS
WEAK HIGH PRESSURE CONTINUING TO BE THE DOMINATING INFLUENCE OF
THE LOCAL WX. EAST AND SOUTHEAST FLOW ON SOUTHERN PERIPHERY OF
THIS HIGH EARLIER ALLOWED FOR LOW LEVEL MOISTURE TO ADVECT IN A
RESULT IN WIDESPREAD LOW CLOUDS. SINCE THEN...DEVELOPING
SOUTHWEST FLOW DUE TO A SHIFT IN THE HIGH POSITION HAS ALLOWED
FOR THE EROSION OF MOST OF THE LOW CLOUDS BUT HAS QUICKLY BEEN
REPLACED BY A THIN VEIL OF CIRRUS. TEMPS LOOKS TO BE LARGELY
UNAFFECTED BY THIS AS WE ARE ALREADY WITHING THREE DEGREES OF
FORECAST HIGH OF ATLANTA CURRENTLY.
FOR TONIGHT...THE FIRST IN A SERIES OF EMBEDDED SHORTWAVES WILL
MOVE THROUGH ZONAL FLOW TO PRODUCE AN AREA OF MAINLY LIGHT RAIN
OVER ALABAMA. MODELS HAVE BEEN BACKING OFF ON HOW MUCH THIS
ENERGY TRANSLATES INTO ACTUAL PRECIP OVER OUR AREA AND INDEED
FEEL AMOUNTS WILL BE ON THE LOW SIDE EVEN OVER WESTERN PORTIONS.
THAT SAID...BASED ON WRF AND HRRR RUNS...IT SHOULD STILL RAIN
EVEN IF ITS LIGHT AND HAVE UPPED CHANCES ALONG THE WEST CENTRAL
BORDER THROUGH 15Z MONDAY. WILL LET EVENING AND MID SHIFT TAKE
ANOTHER LOOK AS MAY STILL BE TOO LOW...GOING JUST BELOW LIKELY AT
THIS POINT.
WAVE CLEARS DURING THE AFTERNOON BUT ANOTHER WILL BE RIGHT ON ITS
HEELS INTO MONDAY NIGHT. THIS ONE WILL BE MOVING MORE SOUTHWEST
TO NORTHEAST TO AFFECT MAINLY THE NORTHERN TIER WITH MID RANGE
CHANCE POPS. IN ADDITION TO LIGHT RAIN...COULD SEE SOME PATCHY
FOG DEVELOPMENT WITH THIS SYSTEM OVER THE MOUNTAINS AND ALONG OUR
WESTERN BORDER WITH ALABAMA.
INCREASING TEMPERATURES THROUGH THE SHORT TERM WITH MID 60S TO
AROUND 70 EXPECTED BY TUESDAY AFTERNOON. THIS WOULD BE A RADICAL
DEPARTURE FROM THE EXTREME COLD OF THIS PAST WEEK AND WOULD
RESULT IN TEMPS SOME 10 DEGREES ABOVE CLIMO.
DEESE
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
SOME CHANGES MADE TO THE EXTENDED BASED ON GUIDANCE WHICH IS
COMING IN QUITE A BIT WARMER FOR LATER IN THE WEEK. AHEAD OF THE
FRONT PROGGED TO STALL ACROSS THE TENNESSEE VALLEY WHICH WILL
SLOWLY MAKE ITS WAY TO THE SOUTHERN APPALACHIANS BY FRIDAY.
RIDGING IN THE GULF REMAINS PRETTY STRONG BUT ALSO STRONGER LOW-
LEVEL WAA. INCREASED TEMPS QUITE A BIT AND ACTUALLY HAVE NEAR-
RECORD TO RECORD WARM MIN TEMPS FOR FRIDAY MORNING. POPS STILL
LOOKING GOOD BUT WILL PROBABLY HAVE TO INCREASE THEM AS WE
PROGRESS THROUGH THE WEEK.
THERE IS SOME CONCERN ABOUT HAZARDOUS WEATHER AS GFS CAPES ARE ON
THE INCREASE ESPECIALLY FOR FRIDAY AFTERNOON AND SOME QPF VALUES
ARE PRETTY HEFTY...BUT WILL NARROW THAT DOWN AS WE GET CLOSER. A
LOT OF UNCERTAINTY ON TIMING OF FROPA AND SUBSEQUENT CAD ONSET...
ECMWF A LITTLE FASTER THAN THE GFS ON FROPA BUT BOTH HAVE SIMILAR
TIMING WITH CAD ONSET....SO MADE NO CHANGES TO SATURDAY /AS THE
SIGNIFICANT COOL-DOWN STARTS/ AND BEYOND BECAUSE OF THAT
UNCERTAINTY. WILL BE INTERESTING TO SEE WHAT SENSIBLE WEATHER
IMPACTS OCCUR WITH THE DIABATICALLY-ENHANCED CAD EVENT FOR EARLY
NEXT WEEK. SEE PREVIOUS DISCUSSION BELOW.
TDP
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
/ISSUED AT 342 AM EST SUN DEC 1 2013/ ONLY SMALL CHANCES FOR
LIGHT RAIN MONDAY NIGHT AND TUESDAY DUE TO THE POTENTIAL OF A WEAK
SHORT WAVE PASSING AND INCREASING ALTHOUGH WEAK SOUTHERLY LOW
LEVEL FLOW. THIS WILL ALSO ALLOW THE AIRMASS TO WARM DURING THIS
PERIOD.
THE GFS AND EUROPEAN ARE IN BETTER AGREEMENT FOR THE EXTENDED
PERIOD. SMALL CHANCES FOR LIGHT SHOWERS CONTINUE WEDNESDAY FROM
SOUTHERLY LOW LEVEL FLOW AHEAD OF THE NEXT FRONT. GFS FASTER
MOVING THE FRONT TO FAR NW GA LATE WEDNESDAY AND THE EUROPEAN
MOVING THE FRONT TO THE OH AND LOWER MS VALLEYS. EITHER WAY
DYNAMICS ARE WEAK.
MOIST SW FLOW ALOFT INCREASES THURSDAY AND CONTINUES INTO
SATURDAY AS THE COLD FRONT SHARPENS OVER THE TN VALLEY/SRN
APPALACHIANS THURSDAY AND MOVES TO CENTRAL GA LATE FRIDAY AND TO
SE GA/N FL ON SATURDAY. OVERALL THIS WILL MEAN A WETTER PERIOD...
MOST SO FOR N GA...ALONG WITH WARMER OVERALL TEMPERATURES UNTIL
THE FRONT PASSES BY.
A COLD AIR DAMMING EVENT LOOKS TO SET UP FOR SUNDAY.
BDL
&&
AVIATION...
18Z UPDATE...
WINDS HAVE BEEN VERY SLOW TO SHIFT OVER TODAY BUT FINALLY STARTING
TO SEE SOME WESTERLY COMPONENT SHOW UP IN THE OBSERVATIONS AND
WILL CARRY AS PREVAILING AT ONSET OF THIS TAF SET. SOUTHEAST
CORNER OF FORECAST AREA INCLUDING MCN THE ONLY ONE HOLDING ONTO
MVFR CIGS BUT DIFFICULT TO DETERMINE EXTENT GIVEN MASKING CIRRUS.
FOR THE FORECAST...EXPECT MVFR TO REEMERGE MON MORNING BUT PERHAPS
A FEW HOURS EARLIER THAN PREVIOUS FORECAST. NOW LOOKING AT AROUND
15Z AT ATL FOR MVFR AND -RA TO DEVELOP. ANOTHER SYSTEM WILL MOVE
ACROSS MONDAY NIGHT AND MAY BRING ANOTHER CHANCE OF -RA BUT JUST
OUTSIDE THIS TAF PERIOD.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON RA CHANCES AND MVFR TIMING.
HIGH ON REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 41 60 48 65 / 10 20 30 30
ATLANTA 46 59 49 66 / 20 50 30 30
BLAIRSVILLE 39 53 45 58 / 10 30 30 40
CARTERSVILLE 42 56 48 66 / 40 40 30 30
COLUMBUS 46 65 50 69 / 20 20 20 10
GAINESVILLE 43 55 48 62 / 10 20 30 30
MACON 41 66 44 69 / 10 20 20 10
ROME 41 56 48 65 / 40 50 30 30
PEACHTREE CITY 41 60 43 67 / 20 50 30 20
VIDALIA 48 66 48 71 / 5 10 20 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DEESE
LONG TERM....TDP
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
144 PM CST SUN DEC 1 2013
.DISCUSSION...
302 AM CST
TODAY...
LOW PRESSURE IS SKIRTING EAST ACROSS THE CENTRAL GREAT LAKES WITH A
TRAILING COLD FRONT SAGGING SOUTH ACROSS THE CENTRAL PART OF THE CWA
EARLY THIS MORNING. A FEW RADAR RETURNS TO OUR NORTH MAINLY
ASSOCIATED WITH MID LEVEL CLOUD COVER...AND PRECIP IS NOT MAKING ITS
WAY TO THE SURFACE...NOR IS IT EXPECTED TO AS THE FRONT CONTINUES TO
SLIP ACROSS THE CWA THROUGH THE MORNING. STRATUS DECK IS EVIDENT ON
IR IMAGERY BUILDING SOUTH BEHIND THE FRONT. EXPECT THESE LOWER
CLOUDS TO BUILD ACROSS THE FORECAST AREA LATER THIS MORNING THEN
REMAIN IN PLACE THROUGH THE DAY AND TONIGHT. WEAK HIGH PRESSURE IS
EXPECTED TO BUILD ACROSS THE AREA TONIGHT...THOUGH MODEL RH FIELDS
SHOW LITTLE IF ANY DISSIPATION OF THE STRATUS DECK. ASSUMING WE STAY
CLOUDY OVERNIGHT...TEMPERATURES SHOULD STAY PROPPED UP INTO THE
UPPER 20S TO LOW 30S DESPITE WINDS LIKELY GOING VERY LIGHT OR
CALM. HOWEVER...IF WE DO SEE CLEARING...WILL HAVE TO MAKE HEFTY
CHANGES TO OVERNIGHT LOWS WHICH COULD FALL 10+ DEGREES MORE THAN
CURRENTLY FORECAST UNDER A STRONG RADIATIONAL COOLING SETUP.
MONDAY...
UPPER LOW DIGS FROM BRITISH COLUMBIA INTO THE PACIFIC NORTHWEST THIS
PERIOD WHILE A LEAD WAVE KICKS EAST ACROSS THE NORTHERN PLAINS WITH
SURFACE LOW UNDERGOING CYCLOGENESIS. ECMWF NO LONGER ADVERTISING
SHORTWAVE EARLY MONDAY...WHICH IS IN LINE WITH OTHER MODEL SOLUTIONS
THUS PULLED MENTION OF POPS MONDAY. BY MONDAY EVENING...H85
BAROCLINIC ZONE SETS UP FROM THE DAKOTAS INTO THE MID MISSISSIPPI
VALLEY WITH A ZONE OF ISENTROPIC ASCENT FOCUSED JUST TO OUR WEST.
STILL UNCERTAIN HOW FAR EAST THE PRECIP WILL EXTEND...BUT BEST
CHANCES WILL BE IN THE NORTHWESTERN PORTIONS OF THE CWA AROUND
ROCKFORD. PRECIP MAY START OFF AS RAIN SNOW MIX...BUT SHOULD
TRANSITION TO ALL RAIN AS THE WARM AIR CONTINUES TO PUSH NORTHWARD.
TEMPERATURES MAY RISE OVERNIGHT MONDAY NIGHT ACROSS PORTIONS IF NOT
ALL OF THE CWA DEPENDING ON HOW QUICKLY THE WARM FRONT LIFTS ACROSS
THE AREA.
TUESDAY THROUGH WEDNESDAY...
LONGWAVE TROUGH CONTINUES TO DEEPEN ACROSS THE WESTERN CONUS WITH
DOWNSTREAM AMPLIFICATION OF THE RIDGE ACROSS THE CENTRAL CONUS.
SURFACE LOW PROGGED TO TRACK FROM THE DAKOTAS INTO THE NORTHERN
LAKES REGION THROUGH THE PERIOD WITH STRONG WARM ADVECTION AHEAD OF
THE LOW WARMING H85 TEMPS TO AROUND 7-8C TUE/WED. 01/00Z EMCWF
ACTUALLY THROWING A WRENCH INTO PREVIOUS FORECAST THINKING FOR
THIS SYSTEM MIDWEEK...TRENDING MUCH FASTER AND MORE IN LINE WITH
THE GFS. NOT QUITE READY TO BITE OFF ON THIS COMPLETELY AS OFTEN
TIMES WITH CLOSED UPPER LOWS SLOWER MODEL SOLUTIONS TEND TO BE
BETTER...AND WOULD NOT BE SURPRISED TO SEE THE GFS AND ECMWF TREND
SLOWER IN THE NEXT COUPLE DAYS. TEMPERATURES ON WEDNESDAY A BIT
TRICKY WITH BIG BUST POTENTIAL. SLIGHTLY FASTER OR SLOWER FROPA
WILL RESULT IN A 15-20 DEGREE RANGE OF POSSIBLE TEMPERATURES.
ECMWF CONTINUES TO BE AGGRESSIVE WITH TEMPERATURES AHEAD OF THE
FRONT...SUGGESTING MID TO UPPER 50S ACROSS MUCH OF THE EASTERN
HALF OF THE CWA EVEN WITH FASTER FROPA. THE GEM...WHICH IS SLOWER
THAN THE GFS/ECMWF NOW SUGGESTING LOW TO MID 60S WEDNESDAY.
TRENDED SLIGHTLY WARMER ACROSS THE EASTERN CWA WHICH WILL HAVE THE
BEST LIKELIHOOD OF SEEING FULL WARMTH AHEAD OF THE FRONT.
THURSDAY THROUGH SATURDAY...
BY THURSDAY...H85 TEMPS SHOULD QUICKLY FALL TO AROUND -10C...THEN
FURTHER COOL TO AROUND -15C TO -18C SATURDAY AS A COLD ARCTIC
AIRMASS TRICKLES INTO THE REGION. BOTH THE GFS AND ECMWF INDICATE
A SERIES OF WAVES LIFTING NORTHEAST ALONG THE FRONT CAUSING PRECIP
NORTH OF THE FRONT AND POSSIBLY IMPACTING EASTERN PORTIONS OF THE
CWA THURSDAY AND THURSDAY NIGHT. OTHERWISE...STRONG HIGH PRESSURE
OVER THE NORTHERN PLAINS WILL BUILD SOUTHEAST WITH RIDGING IN
PLACE FRIDAY INTO THE WEEKEND BRINGING MORE SETTLED AND COLD
WEATHER...WITH HIGHS IN THE TEENS TO LOW 20S...AND SINGLE DIGIT
LOWS FRIDAY AND SATURDAY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* MVFR CIGS WILL BE AROUND THROUGH AT LEAST MID AFTN.
* MFR CIGS RETURN OVERNIGHT.
JEE
//DISCUSSION...UPDATED 18Z...
MAJOR CONCERN IS MVFR CLOUDS FORMING OVER THE LAKE AND MOVING OVER
NE IL. CLOUD DEVELOPMENT AND COVER REALLY BLOSSOMED AFTER 16Z SO
ADJUSTED TAFS TO INCLUDE MVFR CIGS THROUGH MID AFTN. A MID LEVEL
CLOUD DECK IS OV IOWA AND SLOWLY ADVANCING EAST. THINKING THE MVFR
CLOUDS WILL DISSIPATE AS THE MID LEVEL DECK MOVES OVERHEAD. WINDS
ALSO TURN MORE NORTHERLY AT THIS TIME WHICH WOULD REDUCE THE
ADVECTION OF LAKE CLOUDS OVER LAND. THERE IS A CHANCE THAT THE
MVFR CLOUDS MAY LINGER A BIT LONGER THAN CURRENTLY FCST THIS AFTN.
LIGHT WINDS BCM LIGHT AND VARIABLE OVERNIGHT...WITH A NW COMPONENT
AT ORD AND MDW AND EAST AT RFD. THE LIGHT FLOW AND LOW LEVEL
MOISTURE SUGGEST MVFR CIGS REDEVELOP. GUIDANCE TRIES TO FORM FOG
AS WELL...BUT THINKING CLOUD COVER WILL TRUMP FOG. VRB WINDS
CONTINUE INTO THE AM WITH MVFR CIGS SCATTERING OUT. WINDS TURN SE
ON THE BACKSIDE OF THE HIGH TOMORROW WITH SPEEDS ARND 10KT.
THERE IS A SLIGHT CHANCE OF PRECIP IN THE LATE AFTN BUT GUIDANCE
CONTINUES TO PULL FORCING AND MAJORITY OF PRECIP NORTH INTO
WISCONSIN. THE PRECIP WOULD BE A WINTRY MIX OR ALL RAIN...BUT IT
IS SO SLIGHT THAT IT WAS LEFT OUT OF THE TAFS FOR NOW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN CIGS THROUGH 23Z.
* MEDIUM-HIGH CONFIDENCE IN CIG FCST AFT 23Z.
* HIGH CONFIDENCE IN ALL OTHER FCST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...MVFR PROBABLE. CHANCE OF -RASN.
TUESDAY INTO WEDNESDAY...MVFR CIGS POSSIBLE. CHANCE OF RAIN
ESPECIALLY WEDNESDAY.
THURSDAY...SLGT CHANCE OF SHSN WITH MVFR VSBY. OTHERWISE MAINLY
VFR.
FRIDAY AND SATURDAY...MAINLY VFR.
RATZER
&&
.MARINE...
252 AM CST
MAIN MARINE FORECAST CONCERNS FOCUS ON DEVELOPMENT OF STRONG LOW
PRESSURE OVER THE PLAINS MONDAY-TUESDAY...WHICH THEN IS EXPECTED TO
LIFT NORTHEAST ACROSS THE NORTHERN LAKES ON WEDNESDAY. THERE
CONTINUES TO BE SOME SPREAD IN MODEL SOLUTIONS WITH THE DEPTH...
TRACK AND TIMING OF THE LOW.
WEAK LOW PRESSURE WAS OVER LOWER MICHIGAN STATE EARLY THIS
MORNING...WITH A COLD FRONT TRAILING ACROSS SOUTHERN LAKE MICHIGAN.
THE LOW WILL CONTINUE TO TRACK EAST ACROSS THE EASTERN LAKES THROUGH
THIS EVENING...WITH THE FRONT PUSHING SOUTHEAST OF LAKE MICHIGAN
LATER THIS MORNING. WEAK HIGH PRESSURE RIDGING WILL THEN MOVE ACROSS
THE WESTERN LAKES LATER TODAY/TONIGHT...DRIFTING SLOWLY OFF TO THE
EAST ON MONDAY. WITH A RELATIVELY WEAK PUSH TO THE FRONT TODAY...
WINDS WILL SHIFT TO THE NORTH AT GENERALLY LESS THAN 15 KT.
FORECAST MODELS CONTINUE TO DEPICT AN AREA OF LOW PRESSURE
DEVELOPING ACROSS THE HIGH PLAINS BY EARLY MONDAY...WHICH THEN
DEEPENS ACROSS THE CENTRAL PLAINS MONDAY NIGHT. VARIOUS MODEL
SOLUTIONS CONTINUE TO SHOW DIFFERENCES WITH THE EVOLUTION OF THIS
LOW THROUGH MID-WEEK...THOUGH THERE IS SOME CONSENSUS IN LIFTING THE
LOW NORTHEAST ACROSS THE NORTHERN GREAT LAKES WEDNESDAY. GENERALLY
HAVE CONTINUED TO FOLLOW THE SLOWER SOLUTIONS OF THE ECMWF/GEM/UKMET
WITH THIS SYSTEM...THOUGH WILL HAVE TO SEE SOME OF THE DIFFERENCES
IRONED OUT BEFORE CONFIDENCE INCREASES IN DETAILS OF STRENGTH/TRACK
AND TIMING. IT DOES APPEAR THAT THE POTENTIAL EXISTS FOR SOUTHEAST
30-35 KT WINDS AHEAD OF THE LOW LATE TUESDAY INTO WEDNESDAY...AND
WEST GALES LATER WEDNESDAY INTO THURSDAY WITH THE PASSAGE OF THIS
STORM. STILL 3-4 DAYS OUT SO WILL NOT HAVE ANY HEADLINES...THOUGH
WILL MENTION POSSIBLE GALES IN FORECAST FOR THIS PERIOD.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
1201 PM CST Sun Dec 1 2013
.DISCUSSION...
ISSUED 1027 AM CST Sun Dec 1 2013
Another weak cold front drifting southward over the FA this
morning with north winds behind it, although light. Morning warm
up very much ahead of diurnal curve yet again. Have adjusted the
forecast temps up a degree or two, but warm up will be countered
by weak cold air mixing in behind the boundary. Dryness of the
column underestimated and cloud cover not materializing. Have
adjusted the sky grids as well in the short term. Update out
momentarily, to include a removal of the fog wording from this morning.
&&
.AVIATION...
ISSUED 1157 AM CST Sun Dec 1 2013
Similar issues to yesterdays forecast. VFR in the short term,
light and variable winds. Trouble with late tonight and into
tomorrow is the model mishandling of the RH in general. Going with
more of a trend forecast, mid/high level clouds thin and allow
some radiational cooling to set up another fog scenario. Starting
at 3SM, but increasing dwpts at sfc and cooling in the overnight
may result in a drop to IFR for the morning vis. Conservative for
now, but will watch afternoon xovers as well.
HJS
&&
.PREV DISCUSSION...
ISSUED 248 AM CST Sun Dec 1 2013
Main forecast challenge focuses on departing storm system for the
middle and end of the week...and whether or not it will produce
any wintry precipitation across central Illinois.
SHORT TERM...Today through Tuesday
Weak cold front currently across northern Illinois will sink
southward today, eventually becoming stationary along the Ohio
River by evening. Front will be accompanied by little in the way
of sensible weather other than a shift in the wind. Low-level
moisture seen on IR/fog satellite across southeast Missouri/far
southern Illinois is progged by HRRR to remain mostly south of
I-70 today, while patchy mid-level clouds over Iowa into far
northern Illinois stay mostly north of the area. End result will
be mostly sunny skies until later this afternoon when clouds begin
to approach from the northwest. High temperatures will be bit
cooler behind the cold front, ranging from the middle 40s far
northwest around Galesburg to the lower 50s south of I-70.
Boundary will remain in place along the Ohio River through Monday,
before lifting back northward in response to rising upper-level
heights Monday night into Tuesday. Models continue to show a
subtle short-wave rippling eastward out of the Plains late Sunday
night into Monday that could interact with the front to produce
scattered light showers. Forecast soundings remain dry at
low-levels: however, think forcing will be strong enough to
mention a slight chance for showers on Monday. As front lifts
northward, rain chances will shift into the southern Great Lakes
on Tuesday. Brisk southerly winds south of the departing warm
front will bring much warmer air into the region, with Tuesday
afternoon highs reaching the lower to middle 50s.
LONG TERM...Wednesday through Saturday
Forecast becomes more challenging in the extended, as upper low
currently over northwest British Columbia drops southward and
carves a deep trough across the western CONUS by the middle of the
week. Downstream ridging will place the Midwest/Great Lakes in a
broad southwesterly flow pattern, leading to increased precip
chances Wednesday into Thursday. Models have been struggling with
the evolution of a surface low pressure system and its associated
cold front for the past several runs: however, the 00z DEC 1 run
seems to be coming into better agreement. While GFS remains a fast
outlier, the latest ECMWF has sped up the front quite a bit.
Following an ECMWF/GEM consensus yields FROPA across central
Illinois on Wednesday followed by sharply colder conditions for
the end of the week. Main question will be how much precip will
hold back in the colder airmass Thursday and possibly Friday.
Previous runs of the ECMWF had featured quite a bit of wintry
precip Thursday night into Friday as a secondary wave of low
pressure tracked along the departing front. While it still shows the
potential for wintry precip, it has backed off/shifted E/SE with
its latest solution. GEM seems to be the most consistent model
over the past couple of days, so have trended toward its solution.
With cold front passing on Wednesday, will mention a chance for
showers. After FROPA, precip will largely shut off Wednesday
night, before a wave of low pressure tracking from the lower
Mississippi River Valley into the Ohio River Valley brings a
renewed round of precip primarily across the eastern half of the
KILX CWA on Thursday/Thursday night. Have focused highest POPs
along/east of I-57 for both Thursday and Thursday night, tapering
down to just slight chances further west along/west of the
Illinois River. Precip type during the day Thursday will be rain
across the east, with a rain/snow mix along I-55 and mostly light
snow in the Illinois River Valley. As deeper layer of cold air
arrives, precip will change to light snow across the board
Thursday night, with a light accumulation possible. After that,
will hold on to low chance POPs for snow across the far E/SE on
Friday, although if trends continue, these may need to be dropped
entirely. Main weather story for the end of the week will be the
much colder conditions. Highs by Friday and Saturday will only be
in the 20s, with overnight lows in the single digits and teens.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1153 AM CST SUN DEC 1 2013
.DISCUSSION...
302 AM CST
TODAY...
LOW PRESSURE IS SKIRTING EAST ACROSS THE CENTRAL GREAT LAKES WITH A
TRAILING COLD FRONT SAGGING SOUTH ACROSS THE CENTRAL PART OF THE CWA
EARLY THIS MORNING. A FEW RADAR RETURNS TO OUR NORTH MAINLY
ASSOCIATED WITH MID LEVEL CLOUD COVER...AND PRECIP IS NOT MAKING ITS
WAY TO THE SURFACE...NOR IS IT EXPECTED TO AS THE FRONT CONTINUES TO
SLIP ACROSS THE CWA THROUGH THE MORNING. STRATUS DECK IS EVIDENT ON
IR IMAGERY BUILDING SOUTH BEHIND THE FRONT. EXPECT THESE LOWER
CLOUDS TO BUILD ACROSS THE FORECAST AREA LATER THIS MORNING THEN
REMAIN IN PLACE THROUGH THE DAY AND TONIGHT. WEAK HIGH PRESSURE IS
EXPECTED TO BUILD ACROSS THE AREA TONIGHT...THOUGH MODEL RH FIELDS
SHOW LITTLE IF ANY DISSIPATION OF THE STRATUS DECK. ASSUMING WE STAY
CLOUDY OVERNIGHT...TEMPERATURES SHOULD STAY PROPPED UP INTO THE
UPPER 20S TO LOW 30S DESPITE WINDS LIKELY GOING VERY LIGHT OR
CALM. HOWEVER...IF WE DO SEE CLEARING...WILL HAVE TO MAKE HEFTY
CHANGES TO OVERNIGHT LOWS WHICH COULD FALL 10+ DEGREES MORE THAN
CURRENTLY FORECAST UNDER A STRONG RADIATIONAL COOLING SETUP.
MONDAY...
UPPER LOW DIGS FROM BRITISH COLUMBIA INTO THE PACIFIC NORTHWEST THIS
PERIOD WHILE A LEAD WAVE KICKS EAST ACROSS THE NORTHERN PLAINS WITH
SURFACE LOW UNDERGOING CYCLOGENESIS. ECMWF NO LONGER ADVERTISING
SHORTWAVE EARLY MONDAY...WHICH IS IN LINE WITH OTHER MODEL SOLUTIONS
THUS PULLED MENTION OF POPS MONDAY. BY MONDAY EVENING...H85
BAROCLINIC ZONE SETS UP FROM THE DAKOTAS INTO THE MID MISSISSIPPI
VALLEY WITH A ZONE OF ISENTROPIC ASCENT FOCUSED JUST TO OUR WEST.
STILL UNCERTAIN HOW FAR EAST THE PRECIP WILL EXTEND...BUT BEST
CHANCES WILL BE IN THE NORTHWESTERN PORTIONS OF THE CWA AROUND
ROCKFORD. PRECIP MAY START OFF AS RAIN SNOW MIX...BUT SHOULD
TRANSITION TO ALL RAIN AS THE WARM AIR CONTINUES TO PUSH NORTHWARD.
TEMPERATURES MAY RISE OVERNIGHT MONDAY NIGHT ACROSS PORTIONS IF NOT
ALL OF THE CWA DEPENDING ON HOW QUICKLY THE WARM FRONT LIFTS ACROSS
THE AREA.
TUESDAY THROUGH WEDNESDAY...
LONGWAVE TROUGH CONTINUES TO DEEPEN ACROSS THE WESTERN CONUS WITH
DOWNSTREAM AMPLIFICATION OF THE RIDGE ACROSS THE CENTRAL CONUS.
SURFACE LOW PROGGED TO TRACK FROM THE DAKOTAS INTO THE NORTHERN
LAKES REGION THROUGH THE PERIOD WITH STRONG WARM ADVECTION AHEAD OF
THE LOW WARMING H85 TEMPS TO AROUND 7-8C TUE/WED. 01/00Z EMCWF
ACTUALLY THROWING A WRENCH INTO PREVIOUS FORECAST THINKING FOR
THIS SYSTEM MIDWEEK...TRENDING MUCH FASTER AND MORE IN LINE WITH
THE GFS. NOT QUITE READY TO BITE OFF ON THIS COMPLETELY AS OFTEN
TIMES WITH CLOSED UPPER LOWS SLOWER MODEL SOLUTIONS TEND TO BE
BETTER...AND WOULD NOT BE SURPRISED TO SEE THE GFS AND ECMWF TREND
SLOWER IN THE NEXT COUPLE DAYS. TEMPERATURES ON WEDNESDAY A BIT
TRICKY WITH BIG BUST POTENTIAL. SLIGHTLY FASTER OR SLOWER FROPA
WILL RESULT IN A 15-20 DEGREE RANGE OF POSSIBLE TEMPERATURES.
ECMWF CONTINUES TO BE AGGRESSIVE WITH TEMPERATURES AHEAD OF THE
FRONT...SUGGESTING MID TO UPPER 50S ACROSS MUCH OF THE EASTERN
HALF OF THE CWA EVEN WITH FASTER FROPA. THE GEM...WHICH IS SLOWER
THAN THE GFS/ECMWF NOW SUGGESTING LOW TO MID 60S WEDNESDAY.
TRENDED SLIGHTLY WARMER ACROSS THE EASTERN CWA WHICH WILL HAVE THE
BEST LIKELIHOOD OF SEEING FULL WARMTH AHEAD OF THE FRONT.
THURSDAY THROUGH SATURDAY...
BY THURSDAY...H85 TEMPS SHOULD QUICKLY FALL TO AROUND -10C...THEN
FURTHER COOL TO AROUND -15C TO -18C SATURDAY AS A COLD ARCTIC
AIRMASS TRICKLES INTO THE REGION. BOTH THE GFS AND ECMWF INDICATE
A SERIES OF WAVES LIFTING NORTHEAST ALONG THE FRONT CAUSING PRECIP
NORTH OF THE FRONT AND POSSIBLY IMPACTING EASTERN PORTIONS OF THE
CWA THURSDAY AND THURSDAY NIGHT. OTHERWISE...STRONG HIGH PRESSURE
OVER THE NORTHERN PLAINS WILL BUILD SOUTHEAST WITH RIDGING IN
PLACE FRIDAY INTO THE WEEKEND BRINGING MORE SETTLED AND COLD
WEATHER...WITH HIGHS IN THE TEENS TO LOW 20S...AND SINGLE DIGIT
LOWS FRIDAY AND SATURDAY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* MVFR CIGS WILL BE AROUND THROUGH AT LEAST MID AFTN...PSBLY
LONGER.
* MFR CIGS RETURN OVERNIGHT.
JEE
//DISCUSSION...UPDATED 18Z...
MAJOR CONCERN IS MVFR CLOUDS FORMING OVER THE LAKE AND MOVING OVER
NE IL. CLOUD DEVELOPMENT AND COVER REALLY BLOSSOMED AFTER 16Z SO
ADJUSTED TAFS TO INCLUDE MVFR CIGS THROUGH MID AFTN. A MID LEVEL
CLOUD DECK IS OV IOWA AND SLOWLY ADVANCING EAST. THINKING THE MVFR
CLOUDS WILL DISSIPATE AS THE MID LEVEL DECK MOVES OVERHEAD. WINDS
ALSO TURN MORE NORTHERLY AT THIS TIME WHICH WOULD REDUCE THE
ADVECTION OF LAKE CLOUDS OVER LAND. THERE IS A CHANCE THAT THE
MVFR CLOUDS MAY LINGER A BIT LONGER THAN CURRENTLY FCST THIS AFTN.
LIGHT WINDS BCM LIGHT AND VARIABLE OVERNIGHT...WITH A NW COMPONENT
AT ORD AND MDW AND EAST AT RFD. THE LIGHT FLOW AND LOW LEVEL
MOISTURE SUGGEST MVFR CIGS REDEVELOP. GUIDANCE TRIES TO FORM FOG
AS WELL...BUT THINKING CLOUD COVER WILL TRUMP FOG. VRB WINDS
CONTINUE INTO THE AM WITH MVFR CIGS SCATTERING OUT. WINDS TURN SE
ON THE BACKSIDE OF THE HIGH TOMORROW WITH SPEEDS ARND 10KT.
THERE IS A SLIGHT CHANCE OF PRECIP IN THE LATE AFTN BUT GUIDANCE
CONTINUES TO PULL FORCING AND MAJORITY OF PRECIP NORTH INTO
WISCONSIN. THE PRECIP WOULD BE A WINTRY MIX OR ALL RAIN...BUT IT
IS SO SLIGHT THAT IT WAS LEFT OUT OF THE TAFS FOR NOW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN CIGS THROUGH 22Z...MEDIUM CONFIDENCE IN MVFR
CIGS SCATTERING OUT THIS AFTN.
* HIGH CONFIDENCE IN ALL OTHER FCST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...MVFR PROBABLE. CHANCE OF -RASN.
TUESDAY INTO WEDNESDAY...MVFR CIGS POSSIBLE. CHANCE OF RAIN
ESPECIALLY WEDNESDAY.
THURSDAY...SLGT CHANCE OF SHSN WITH MVFR VSBY. OTHERWISE MAINLY
VFR.
FRIDAY AND SATURDAY...MAINLY VFR.
RATZER
&&
.MARINE...
252 AM CST
MAIN MARINE FORECAST CONCERNS FOCUS ON DEVELOPMENT OF STRONG LOW
PRESSURE OVER THE PLAINS MONDAY-TUESDAY...WHICH THEN IS EXPECTED TO
LIFT NORTHEAST ACROSS THE NORTHERN LAKES ON WEDNESDAY. THERE
CONTINUES TO BE SOME SPREAD IN MODEL SOLUTIONS WITH THE DEPTH...
TRACK AND TIMING OF THE LOW.
WEAK LOW PRESSURE WAS OVER LOWER MICHIGAN STATE EARLY THIS
MORNING...WITH A COLD FRONT TRAILING ACROSS SOUTHERN LAKE MICHIGAN.
THE LOW WILL CONTINUE TO TRACK EAST ACROSS THE EASTERN LAKES THROUGH
THIS EVENING...WITH THE FRONT PUSHING SOUTHEAST OF LAKE MICHIGAN
LATER THIS MORNING. WEAK HIGH PRESSURE RIDGING WILL THEN MOVE ACROSS
THE WESTERN LAKES LATER TODAY/TONIGHT...DRIFTING SLOWLY OFF TO THE
EAST ON MONDAY. WITH A RELATIVELY WEAK PUSH TO THE FRONT TODAY...
WINDS WILL SHIFT TO THE NORTH AT GENERALLY LESS THAN 15 KT.
FORECAST MODELS CONTINUE TO DEPICT AN AREA OF LOW PRESSURE
DEVELOPING ACROSS THE HIGH PLAINS BY EARLY MONDAY...WHICH THEN
DEEPENS ACROSS THE CENTRAL PLAINS MONDAY NIGHT. VARIOUS MODEL
SOLUTIONS CONTINUE TO SHOW DIFFERENCES WITH THE EVOLUTION OF THIS
LOW THROUGH MID-WEEK...THOUGH THERE IS SOME CONSENSUS IN LIFTING THE
LOW NORTHEAST ACROSS THE NORTHERN GREAT LAKES WEDNESDAY. GENERALLY
HAVE CONTINUED TO FOLLOW THE SLOWER SOLUTIONS OF THE ECMWF/GEM/UKMET
WITH THIS SYSTEM...THOUGH WILL HAVE TO SEE SOME OF THE DIFFERENCES
IRONED OUT BEFORE CONFIDENCE INCREASES IN DETAILS OF STRENGTH/TRACK
AND TIMING. IT DOES APPEAR THAT THE POTENTIAL EXISTS FOR SOUTHEAST
30-35 KT WINDS AHEAD OF THE LOW LATE TUESDAY INTO WEDNESDAY...AND
WEST GALES LATER WEDNESDAY INTO THURSDAY WITH THE PASSAGE OF THIS
STORM. STILL 3-4 DAYS OUT SO WILL NOT HAVE ANY HEADLINES...THOUGH
WILL MENTION POSSIBLE GALES IN FORECAST FOR THIS PERIOD.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
1038 AM CST Sun Dec 1 2013
.DISCUSSION...
ISSUED 1027 AM CST Sun Dec 1 2013
Another weak cold front drifting southward over the FA this
morning with north winds behind it, although light. Morning warm
up very much ahead of diurnal curve yet again. Have adjusted the
forecast temps up a degree or two, but warm up will be countered
by weak cold air mixing in behind the boundary. Dryness of the
column underestimated and cloud cover not materializing. Have
adjusted the sky grids as well in the short term. Update out
momentarily, to include a removal of the fog wording from this morning.
HJS
&&
.AVIATION...
ISSUED 535 AM CST Sun Dec 1 2013
Will see a few hours of MVFR vsbys in fog early this morning, then
VFR conditions are expected into this evening, before another threat
for some lower vsbys in fog late tonight. A weak cold front was
pushing across the forecast area early this morning with winds
ahead of the front light southwesterly, and light northwest to north
winds were reported behind the boundary. forecast soundings and
time-height cross sections indicate other than some sct-bkn cirrus
at times today, not much in the way of significant cloud cover
expected until this evening when a weak weather system well out to
our west spreads clouds into our area. Cig heights look to be
from 8000-1000 feet AGL later this evening. Due to the very light
wind regime and despite the expected cloud cover tonight, we do
expect some light fog to develop after 06z over most of the area
with short range ensembles suggesting areas around I-74 seeing
the higher probabilities for lower vsbys due to the fog. For now,
will bring vsbys down to 4-5sm in br late tonight.
Smith
&&
.PREV DISCUSSION...
ISSUED 248 AM CST Sun Dec 1 2013
Main forecast challenge focuses on departing storm system for the
middle and end of the week...and whether or not it will produce
any wintry precipitation across central Illinois.
SHORT TERM...Today through Tuesday
Weak cold front currently across northern Illinois will sink
southward today, eventually becoming stationary along the Ohio
River by evening. Front will be accompanied by little in the way
of sensible weather other than a shift in the wind. Low-level
moisture seen on IR/fog satellite across southeast Missouri/far
southern Illinois is progged by HRRR to remain mostly south of
I-70 today, while patchy mid-level clouds over Iowa into far
northern Illinois stay mostly north of the area. End result will
be mostly sunny skies until later this afternoon when clouds begin
to approach from the northwest. High temperatures will be bit
cooler behind the cold front, ranging from the middle 40s far
northwest around Galesburg to the lower 50s south of I-70.
Boundary will remain in place along the Ohio River through Monday,
before lifting back northward in response to rising upper-level
heights Monday night into Tuesday. Models continue to show a
subtle short-wave rippling eastward out of the Plains late Sunday
night into Monday that could interact with the front to produce
scattered light showers. Forecast soundings remain dry at
low-levels: however, think forcing will be strong enough to
mention a slight chance for showers on Monday. As front lifts
northward, rain chances will shift into the southern Great Lakes
on Tuesday. Brisk southerly winds south of the departing warm
front will bring much warmer air into the region, with Tuesday
afternoon highs reaching the lower to middle 50s.
LONG TERM...Wednesday through Saturday
Forecast becomes more challenging in the extended, as upper low
currently over northwest British Columbia drops southward and
carves a deep trough across the western CONUS by the middle of the
week. Downstream ridging will place the Midwest/Great Lakes in a
broad southwesterly flow pattern, leading to increased precip
chances Wednesday into Thursday. Models have been struggling with
the evolution of a surface low pressure system and its associated
cold front for the past several runs: however, the 00z DEC 1 run
seems to be coming into better agreement. While GFS remains a fast
outlier, the latest ECMWF has sped up the front quite a bit.
Following an ECMWF/GEM consensus yields FROPA across central
Illinois on Wednesday followed by sharply colder conditions for
the end of the week. Main question will be how much precip will
hold back in the colder airmass Thursday and possibly Friday.
Previous runs of the ECMWF had featured quite a bit of wintry
precip Thursday night into Friday as a secondary wave of low
pressure tracked along the departing front. While it still shows the
potential for wintry precip, it has backed off/shifted E/SE with
its latest solution. GEM seems to be the most consistent model
over the past couple of days, so have trended toward its solution.
With cold front passing on Wednesday, will mention a chance for
showers. After FROPA, precip will largely shut off Wednesday
night, before a wave of low pressure tracking from the lower
Mississippi River Valley into the Ohio River Valley brings a
renewed round of precip primarily across the eastern half of the
KILX CWA on Thursday/Thursday night. Have focused highest POPs
along/east of I-57 for both Thursday and Thursday night, tapering
down to just slight chances further west along/west of the
Illinois River. Precip type during the day Thursday will be rain
across the east, with a rain/snow mix along I-55 and mostly light
snow in the Illinois River Valley. As deeper layer of cold air
arrives, precip will change to light snow across the board
Thursday night, with a light accumulation possible. After that,
will hold on to low chance POPs for snow across the far E/SE on
Friday, although if trends continue, these may need to be dropped
entirely. Main weather story for the end of the week will be the
much colder conditions. Highs by Friday and Saturday will only be
in the 20s, with overnight lows in the single digits and teens.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
804 AM CST SUN DEC 1 2013
.DISCUSSION...
302 AM CST
TODAY...
LOW PRESSURE IS SKIRTING EAST ACROSS THE CENTRAL GREAT LAKES WITH A
TRAILING COLD FRONT SAGGING SOUTH ACROSS THE CENTRAL PART OF THE CWA
EARLY THIS MORNING. A FEW RADAR RETURNS TO OUR NORTH MAINLY
ASSOCIATED WITH MID LEVEL CLOUD COVER...AND PRECIP IS NOT MAKING ITS
WAY TO THE SURFACE...NOR IS IT EXPECTED TO AS THE FRONT CONTINUES TO
SLIP ACROSS THE CWA THROUGH THE MORNING. STRATUS DECK IS EVIDENT ON
IR IMAGERY BUILDING SOUTH BEHIND THE FRONT. EXPECT THESE LOWER
CLOUDS TO BUILD ACROSS THE FORECAST AREA LATER THIS MORNING THEN
REMAIN IN PLACE THROUGH THE DAY AND TONIGHT. WEAK HIGH PRESSURE IS
EXPECTED TO BUILD ACROSS THE AREA TONIGHT...THOUGH MODEL RH FIELDS
SHOW LITTLE IF ANY DISSIPATION OF THE STRATUS DECK. ASSUMING WE STAY
CLOUDY OVERNIGHT...TEMPERATURES SHOULD STAY PROPPED UP INTO THE
UPPER 20S TO LOW 30S DESPITE WINDS LIKELY GOING VERY LIGHT OR
CALM. HOWEVER...IF WE DO SEE CLEARING...WILL HAVE TO MAKE HEFTY
CHANGES TO OVERNIGHT LOWS WHICH COULD FALL 10+ DEGREES MORE THAN
CURRENTLY FORECAST UNDER A STRONG RADIATIONAL COOLING SETUP.
MONDAY...
UPPER LOW DIGS FROM BRITISH COLUMBIA INTO THE PACIFIC NORTHWEST THIS
PERIOD WHILE A LEAD WAVE KICKS EAST ACROSS THE NORTHERN PLAINS WITH
SURFACE LOW UNDERGOING CYCLOGENESIS. ECMWF NO LONGER ADVERTISING
SHORTWAVE EARLY MONDAY...WHICH IS IN LINE WITH OTHER MODEL SOLUTIONS
THUS PULLED MENTION OF POPS MONDAY. BY MONDAY EVENING...H85
BAROCLINIC ZONE SETS UP FROM THE DAKOTAS INTO THE MID MISSISSIPPI
VALLEY WITH A ZONE OF ISENTROPIC ASCENT FOCUSED JUST TO OUR WEST.
STILL UNCERTAIN HOW FAR EAST THE PRECIP WILL EXTEND...BUT BEST
CHANCES WILL BE IN THE NORTHWESTERN PORTIONS OF THE CWA AROUND
ROCKFORD. PRECIP MAY START OFF AS RAIN SNOW MIX...BUT SHOULD
TRANSITION TO ALL RAIN AS THE WARM AIR CONTINUES TO PUSH NORTHWARD.
TEMPERATURES MAY RISE OVERNIGHT MONDAY NIGHT ACROSS PORTIONS IF NOT
ALL OF THE CWA DEPENDING ON HOW QUICKLY THE WARM FRONT LIFTS ACROSS
THE AREA.
TUESDAY THROUGH WEDNESDAY...
LONGWAVE TROUGH CONTINUES TO DEEPEN ACROSS THE WESTERN CONUS WITH
DOWNSTREAM AMPLIFICATION OF THE RIDGE ACROSS THE CENTRAL CONUS.
SURFACE LOW PROGGED TO TRACK FROM THE DAKOTAS INTO THE NORTHERN
LAKES REGION THROUGH THE PERIOD WITH STRONG WARM ADVECTION AHEAD OF
THE LOW WARMING H85 TEMPS TO AROUND 7-8C TUE/WED. 01/00Z EMCWF
ACTUALLY THROWING A WRENCH INTO PREVIOUS FORECAST THINKING FOR
THIS SYSTEM MIDWEEK...TRENDING MUCH FASTER AND MORE IN LINE WITH
THE GFS. NOT QUITE READY TO BITE OFF ON THIS COMPLETELY AS OFTEN
TIMES WITH CLOSED UPPER LOWS SLOWER MODEL SOLUTIONS TEND TO BE
BETTER...AND WOULD NOT BE SURPRISED TO SEE THE GFS AND ECMWF TREND
SLOWER IN THE NEXT COUPLE DAYS. TEMPERATURES ON WEDNESDAY A BIT
TRICKY WITH BIG BUST POTENTIAL. SLIGHTLY FASTER OR SLOWER FROPA
WILL RESULT IN A 15-20 DEGREE RANGE OF POSSIBLE TEMPERATURES.
ECMWF CONTINUES TO BE AGGRESSIVE WITH TEMPERATURES AHEAD OF THE
FRONT...SUGGESTING MID TO UPPER 50S ACROSS MUCH OF THE EASTERN
HALF OF THE CWA EVEN WITH FASTER FROPA. THE GEM...WHICH IS SLOWER
THAN THE GFS/ECMWF NOW SUGGESTING LOW TO MID 60S WEDNESDAY.
TRENDED SLIGHTLY WARMER ACROSS THE EASTERN CWA WHICH WILL HAVE THE
BEST LIKELIHOOD OF SEEING FULL WARMTH AHEAD OF THE FRONT.
THURSDAY THROUGH SATURDAY...
BY THURSDAY...H85 TEMPS SHOULD QUICKLY FALL TO AROUND -10C...THEN
FURTHER COOL TO AROUND -15C TO -18C SATURDAY AS A COLD ARCTIC
AIRMASS TRICKLES INTO THE REGION. BOTH THE GFS AND ECMWF INDICATE
A SERIES OF WAVES LIFTING NORTHEAST ALONG THE FRONT CAUSING PRECIP
NORTH OF THE FRONT AND POSSIBLY IMPACTING EASTERN PORTIONS OF THE
CWA THURSDAY AND THURSDAY NIGHT. OTHERWISE...STRONG HIGH PRESSURE
OVER THE NORTHERN PLAINS WILL BUILD SOUTHEAST WITH RIDGING IN
PLACE FRIDAY INTO THE WEEKEND BRINGING MORE SETTLED AND COLD
WEATHER...WITH HIGHS IN THE TEENS TO LOW 20S...AND SINGLE DIGIT
LOWS FRIDAY AND SATURDAY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* MVFR CIGS THROUGH MID-DAY AND MAY LINGER INTO TONIGHT.
JEE
//DISCUSSION...UPDATED 12Z...
COLD FRONT HAS JUST MOVED THROUGH TERMINALS EARLY THIS MORNING AND
WILL CONTINUE TO TRACK OFF TO THE SOUTHEAST TODAY. LIGHT WINDS
LESS THAN 10 KT INITIALLY SHIFTING NNW EXPECTED TO BECOME NORTH OR
NE LATER THIS MORNING. WITH THIS SWITCH TO NNE WINDS...CONCERN
BECOMES LARGE AREA OF MVFR STRATUS OVER NORTHERN LAKE MICHIGAN
WHICH MODEL GUIDANCE CONTINUES TO INDICATE WILL MOVE INTO THE
TERMINALS BY MID-DAY. CEILINGS UPSTREAM RANGE FROM 1500-3500 FT
CURRENTLY...THOUGH AREA OF 2500 FT STRATUS ALONG THE EAST SHORE OF
THE LAKE APPEARS TO BE BUILDING SOUTHWEST SIMILAR TO MODEL
FORECASTS AND IS EXPECTED INTO ORD/MDW AREA 16-18Z. WEAK HIGH
PRESSURE DEVELOPS ACROSS THE AREA TONIGHT...MAINTAINING LIGHT NNE
WINDS. LACK OF STRONG SUBSIDENCE OR STRONGER LOW LEVEL WINDS
RAISES QUESTION OF HOW LONG MVFR DECK WILL HANG AROUND. MODELS
DIFFER IN THEIR SOLUTIONS WHICH LOWERS CONFIDENCE. HAVE MAINTAINED
MVFR CIGS THROUGH THE NIGHT WHICH MAY BE ON THE PESSIMISTIC SIDE.
ONCE SURFACE HIGH PASSES AND WINDS VEER SOUTHEAST MONDAY
MORNING...IT DOES APPEAR THAT LOWER CLOUDS SHOULD SCATTER...WHILE
VFR CLOUDS INCREASE.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM-HIGH CONFIDENCE IN CIG TRENDS.
* LOW CONFIDENCE IN HOW LONG MVFR...ESPECIALLY BKN014 CIGS...WILL
LAST.
* HIGH CONFIDENCE IN ALL OTHER FORECAST PARAMETERS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...MVFR PROBABLE. CHANCE OF -RASN.
TUESDAY INTO WEDNESDAY...MVFR CIGS POSSIBLE. CHANCE OF RAIN
ESPECIALLY WEDNESDAY.
THURSDAY...SLGT CHANCE OF SHSN WITH MVFR VSBY. OTHERWISE MAINLY
VFR.
FRIDAY AND SATURDAY...MAINLY VFR.
RATZER
&&
.MARINE...
252 AM CST
MAIN MARINE FORECAST CONCERNS FOCUS ON DEVELOPMENT OF STRONG LOW
PRESSURE OVER THE PLAINS MONDAY-TUESDAY...WHICH THEN IS EXPECTED TO
LIFT NORTHEAST ACROSS THE NORTHERN LAKES ON WEDNESDAY. THERE
CONTINUES TO BE SOME SPREAD IN MODEL SOLUTIONS WITH THE DEPTH...
TRACK AND TIMING OF THE LOW.
WEAK LOW PRESSURE WAS OVER LOWER MICHIGAN STATE EARLY THIS
MORNING...WITH A COLD FRONT TRAILING ACROSS SOUTHERN LAKE MICHIGAN.
THE LOW WILL CONTINUE TO TRACK EAST ACROSS THE EASTERN LAKES THROUGH
THIS EVENING...WITH THE FRONT PUSHING SOUTHEAST OF LAKE MICHIGAN
LATER THIS MORNING. WEAK HIGH PRESSURE RIDGING WILL THEN MOVE ACROSS
THE WESTERN LAKES LATER TODAY/TONIGHT...DRIFTING SLOWLY OFF TO THE
EAST ON MONDAY. WITH A RELATIVELY WEAK PUSH TO THE FRONT TODAY...
WINDS WILL SHIFT TO THE NORTH AT GENERALLY LESS THAN 15 KT.
FORECAST MODELS CONTINUE TO DEPICT AN AREA OF LOW PRESSURE
DEVELOPING ACROSS THE HIGH PLAINS BY EARLY MONDAY...WHICH THEN
DEEPENS ACROSS THE CENTRAL PLAINS MONDAY NIGHT. VARIOUS MODEL
SOLUTIONS CONTINUE TO SHOW DIFFERENCES WITH THE EVOLUTION OF THIS
LOW THROUGH MID-WEEK...THOUGH THERE IS SOME CONSENSUS IN LIFTING THE
LOW NORTHEAST ACROSS THE NORTHERN GREAT LAKES WEDNESDAY. GENERALLY
HAVE CONTINUED TO FOLLOW THE SLOWER SOLUTIONS OF THE ECMWF/GEM/UKMET
WITH THIS SYSTEM...THOUGH WILL HAVE TO SEE SOME OF THE DIFFERENCES
IRONED OUT BEFORE CONFIDENCE INCREASES IN DETAILS OF STRENGTH/TRACK
AND TIMING. IT DOES APPEAR THAT THE POTENTIAL EXISTS FOR SOUTHEAST
30-35 KT WINDS AHEAD OF THE LOW LATE TUESDAY INTO WEDNESDAY...AND
WEST GALES LATER WEDNESDAY INTO THURSDAY WITH THE PASSAGE OF THIS
STORM. STILL 3-4 DAYS OUT SO WILL NOT HAVE ANY HEADLINES...THOUGH
WILL MENTION POSSIBLE GALES IN FORECAST FOR THIS PERIOD.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
542 AM CST Sun Dec 1 2013
.DISCUSSION...
ISSUED 248 AM CST Sun Dec 1 2013
Main forecast challenge focuses on departing storm system for the
middle and end of the week...and whether or not it will produce
any wintry precipitation across central Illinois.
SHORT TERM...Today through Tuesday
Weak cold front currently across northern Illinois will sink
southward today, eventually becoming stationary along the Ohio
River by evening. Front will be accompanied by little in the way
of sensible weather other than a shift in the wind. Low-level
moisture seen on IR/fog satellite across southeast Missouri/far
southern Illinois is progged by HRRR to remain mostly south of
I-70 today, while patchy mid-level clouds over Iowa into far
northern Illinois stay mostly north of the area. End result will
be mostly sunny skies until later this afternoon when clouds begin
to approach from the northwest. High temperatures will be bit
cooler behind the cold front, ranging from the middle 40s far
northwest around Galesburg to the lower 50s south of I-70.
Boundary will remain in place along the Ohio River through Monday,
before lifting back northward in response to rising upper-level
heights Monday night into Tuesday. Models continue to show a
subtle short-wave rippling eastward out of the Plains late Sunday
night into Monday that could interact with the front to produce
scattered light showers. Forecast soundings remain dry at
low-levels: however, think forcing will be strong enough to
mention a slight chance for showers on Monday. As front lifts
northward, rain chances will shift into the southern Great Lakes
on Tuesday. Brisk southerly winds south of the departing warm
front will bring much warmer air into the region, with Tuesday
afternoon highs reaching the lower to middle 50s.
LONG TERM...Wednesday through Saturday
Forecast becomes more challenging in the extended, as upper low
currently over northwest British Columbia drops southward and
carves a deep trough across the western CONUS by the middle of the
week. Downstream ridging will place the Midwest/Great Lakes in a
broad southwesterly flow pattern, leading to increased precip
chances Wednesday into Thursday. Models have been struggling with
the evolution of a surface low pressure system and its associated
cold front for the past several runs: however, the 00z DEC 1 run
seems to be coming into better agreement. While GFS remains a fast
outlier, the latest ECMWF has sped up the front quite a bit.
Following an ECMWF/GEM consensus yields FROPA across central
Illinois on Wednesday followed by sharply colder conditions for
the end of the week. Main question will be how much precip will
hold back in the colder airmass Thursday and possibly Friday.
Previous runs of the ECMWF had featured quite a bit of wintry
precip Thursday night into Friday as a secondary wave of low
pressure tracked along the departing front. While it still shows the
potential for wintry precip, it has backed off/shifted E/SE with
its latest solution. GEM seems to be the most consistent model
over the past couple of days, so have trended toward its solution.
With cold front passing on Wednesday, will mention a chance for
showers. After FROPA, precip will largely shut off Wednesday
night, before a wave of low pressure tracking from the lower
Mississippi River Valley into the Ohio River Valley brings a
renewed round of precip primarily across the eastern half of the
KILX CWA on Thursday/Thursday night. Have focused highest POPs
along/east of I-57 for both Thursday and Thursday night, tapering
down to just slight chances further west along/west of the
Illinois River. Precip type during the day Thursday will be rain
across the east, with a rain/snow mix along I-55 and mostly light
snow in the Illinois River Valley. As deeper layer of cold air
arrives, precip will change to light snow across the board
Thursday night, with a light accumulation possible. After that,
will hold on to low chance POPs for snow across the far E/SE on
Friday, although if trends continue, these may need to be dropped
entirely. Main weather story for the end of the week will be the
much colder conditions. Highs by Friday and Saturday will only be
in the 20s, with overnight lows in the single digits and teens.
&&
.AVIATION...
ISSUED 535 AM CST Sun Dec 1 2013
Will see a few hours of MVFR vsbys in fog early this morning, then
VFR conditions are expected into this evening, before another threat
for some lower vsbys in fog late tonight. A weak cold front was
pushing across the forecast area early this morning with winds
ahead of the front light southwesterly, and light northwest to north
winds were reported behind the boundary. forecast soundings and
time-height cross sections indicate other than some sct-bkn cirrus
at times today, not much in the way of significant cloud cover
expected until this evening when a weak weather system well out to
our west spreads clouds into our area. Cig heights look to be
from 8000-1000 feet AGL later this evening. Due to the very light
wind regime and despite the expected cloud cover tonight, we do
expect some light fog to develop after 06z over most of the area
with short range ensembles suggesting areas around I-74 seeing
the higher probabilities for lower vsbys due to the fog. For now,
will bring vsbys down to 4-5sm in br late tonight.
Smith
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
252 AM CST SUN DEC 1 2013
.DISCUSSION...
252 PM CST
SYNOPSIS...MORE SEASONAL TEMPERATURES WILL BE WITH US THROUGH EARLY
NEXT WEEK...WITH TEMPS PEAKING MID WEEK. THEN TEMPS QUICKLY FALL
TO WELL BELOW NORMAL BY NEXT WEEKEND. THERE A FEW SLIGHT CHANCES OF
PRECIP EARLY NEXT WEEK WITH A MUCH BETTER CHANCE FOR PRECIP MID
WEEK. THE MID WEEK SYSTEM WILL BRING MOSTLY RAIN WITH A CHANCE OF
WINTRY PRECIP LATE NEXT WEEK.
REST OF TODAY THROUGH SUNDAY...
WEAK LOW PRESSURE IS OVER LAKE SUPERIOR AND NORTHERN WI WITH ITS
COLD FRONT STRETCHING FROM MEDFORD WI THROUGH MASON CITY IA. THE
LOW WILL CONTINUE EASTWARD AND DISSIPATE OVER THE EASTERN GREAT
LAKES SUNDAY NIGHT. WE HAVE MIXED MUCH MORE THAN WE WERE EXPECTING
TODAY...RESULTING IN HIGH TEMPS IN THE LOWER 50S. NOT BAD FOR LATE
NOVEMBER! AS SUCH RAISED LOW TEMPS BY A COUPLE DEGREES TONIGHT.
CLOUDS WILL ALSO BE INCREASING THIS EVENING AND OVERNIGHT LIMITING
COOLING.
AN UPPER LEVEL SHORTWAVE PASSES OVERHEAD TOMORROW MORNING WITH NO
PRECIP EXPECTED. CAA ALOFT AND WEAK SURFACE FLOW LEAD ME TO BELIEVE
WE WILL BE A BIT COOLER TOMORROW WITH HIGHS AROUND 40.
MONDAY AND TUESDAY...
ANOTHER SLIGHTLY DEEPER UPPER LEVEL SHORTWAVE ARRIVES MONDAY.
THIS TROUGH IS ALSO FURTHER SOUTH MOVING RIGHT OVER NORTHERN
IL...WHICH MAY PROVIDE JUST ENOUGH FORCING FOR A LITTLE LIGHT
PRECIP. TEMPS WILL BE ON THE RISE THROUGH THE MORNING SO WENT WITH
LIGHT SNOW AT FIRST TURNING OVER TO RAIN BY MONDAY AFTERNOON. THE
PRECIP WILL TRAVEL EAST WITH THE SHORTWAVE THROUGH THE DAY. HIGH
TEMPS ON MONDAY WILL ONCE AGAIN BE AROUND 40.
AN UPPER LEVEL VORT STREAMER PASSES JUST TO THE NORTH LATE MONDAY
NIGHT WHICH MAY PRODUCE A LITTLE LIGHT SNOW OVER NORTH CENTRAL IL.
MAY SEE A LITTLE MORE PRECIP COVERAGE TUESDAY MORNING WITH PRECIP
TURNING OVER TO RAIN AS TEMPS WARM. THE FORCING THEN LIFTS OFF TO
THE NE SO KEPT A SLIGHT CHANCE OF PRECIP OVER NORTH CENTRAL IL
TUESDAY AFTERNOON WITH THE MAJORITY OF PRECIP STAYING NORTH OF OUR
REGION CLOSER TO THE VORT STREAMER.
A STATIONARY FRONT THEN STRETCHES OVER NORTHERN IL TUESDAY NIGHT SO
KEPT A SLIGHT CHANCE TO CHANCE OF RAIN GOING. WAA ALOFT WILL KEEP
TUESDAY NIGHT TEMPS ABOVE FREEZING.
WEDNESDAY THROUGH FRIDAY...
THE UPPER LEVEL RIDGE SHIFTS TO THE EAST WITH SOUTHWEST FLOW SETTING
UP THROUGH LATE FRIDAY. THE UPPER LEVEL TROUGH AXIS PASSES OVERHEAD
SATURDAY. LONG DISTANCE GUIDANCE AGREES ON THE OVERALL
PATTERN...BUT THE GFS AND ECMWF DIFFER GREATLY ON WHEN THESE
FEATURES WILL IMPACT THE REGION. WENT WITH THE MORE STEADY ECMWF IN
THE LONG TERM AS THE GFS LOOKS MUCH TOO FAST.
A SURFACE LOW MOVES OVER THE CENTRAL PLAINS LATE TUESDAY NIGHT INTO
WEDNESDAY WITH WAA IMPACTING THE REGION TUESDAY NIGHT THROUGH
WEDNESDAY EVENING. WITH ALL OF THE WAA RAISED TEMPS TUESDAY NIGHT
AND WEDNESDAY...AND HONESTLY...STILL THINK TEMPS ARE TOO LOW. COULD
EASILY SEE AT LEAST LOW 50S ON WEDNESDAY.
RAIN ARRIVES BEHIND THE WARM FRONT WEDNESDAY AFTERNOON WITH GUIDANCE
BACKING OFF A LITTLE WITH QPF...TO AROUND 0.1 INCHES. THE LOWS COLD
FRONT SWINGS THROUGH WED NIGHT/THURSDAY WITH TEMPS CRASHING BEHIND
IT. COULD EASILY SEE A 10+ DEGREE DIFFERENCE IN HIGH TEMPS WEDNESDAY
AND THURSDAY. PRECIP MAY LINGER A BIT BEHIND THE COLD
FRONT...MEANING WINTRY PRECIP IS POSSIBLE. GUIDANCE INDICATES
PRECIP WILL ALSO FORM AHEAD OF THE UPPER LEVEL TROUGH
AXIS...RESULTING IN RAIN/SNOW THURSDAY BECOMING ALL SNOW THURSDAY
NIGHT THROUGH LATE FRIDAY.
ARCTIC AIR MOVES IN WITH THE TROUGH AXIS RESULTING IN HIGH TEMPS IN
THE 20S LATE NEXT WEEK. MAY EVEN SEE HIGH TEMPS IN THE TEENS ON
SATURDAY.
CONFIDENCE IS HIGH THAT THE SYSTEM WILL IMPACT THE REGION MID NEXT
WEEK...PRECIP WILL BE MOSTLY RAIN...AND IN TEMP TRENDS. MEDIUM
CONFIDENCE IN HOW LONG PRECIP WILL LINGER.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS LIKELY DEVELOPING SUNDAY MORNING AND LINGERING THROUGH
THE DAY.
RATZER
//DISCUSSION...UPDATED 06Z...
WEAK LOW PRESSURE WAS OVER NORTHERN LOWER MICHIGAN LATE THIS
EVENING...WITH A WEAK/DIFFUSE COLD FRONT TRAILING ACROSS SOUTHERN
WI. THIS FRONT WILL CONTINUE TO MOVE SOUTHEAST ACROSS THE TERMINALS
DURING THE EARLY MORNING HOURS...WITH WINDS SHIFTING FROM LIGHT
WEST-SOUTHWEST TO NORTHERLY. WINDS WILL BECOME MORE NORTH-
NORTHEAST LATER IN THE MORNING...THOUGH WITH SPEEDS GENERALLY LESS
THAN 10 KT. LARGE AREA OF MVFR STRATUS TRAILING THE FRONT ACROSS
NORTHERN WI/MI...THOUGH MAKING SLOW SOUTHWARD PROGRESS PER GOES IR
SATELLITE IMAGERY. HIGH-RES RAPID REFRESH ENSEMBLE GUIDANCE
INDICATES MVFR CIGS ARRIVE AT ORD/MDW DURING THE LATE MORNING
HOURS AS WINDS TURN A BIT MORE NORTH-NORTHEAST. LITTLE CHANGE IN
CONDITIONS THEN ANTICIPATED THROUGH THE DAY/EARLY EVENING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM-HIGH CONFIDENCE IN MVFR DEVELOPING SUNDAY BUT LOW
CONFIDENCE IN TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...MVFR PROBABLE. CHANCE OF -SN.
MONDAY NIGHT INTO TUESDAY...MVFR CIGS POSSIBLE.
WEDNESDAY...MVFR CIGS LIKELY WITH IFR POSSIBLE. CHANCE OF -RA.
THURSDAY AND FRIDAY...MVFR CIGS LIKELY WITH IFR POSSIBLE. CHANCE OF
-SN
IZZI
&&
.MARINE...
252 AM CST
MAIN MARINE FORECAST CONCERNS FOCUS ON DEVELOPMENT OF STRONG LOW
PRESSURE OVER THE PLAINS MONDAY-TUESDAY...WHICH THEN IS EXPECTED TO
LIFT NORTHEAST ACROSS THE NORTHERN LAKES ON WEDNESDAY. THERE
CONTINUES TO BE SOME SPREAD IN MODEL SOLUTIONS WITH THE DEPTH...
TRACK AND TIMING OF THE LOW.
WEAK LOW PRESSURE WAS OVER LOWER MICHIGAN STATE EARLY THIS
MORNING...WITH A COLD FRONT TRAILING ACROSS SOUTHERN LAKE MICHIGAN.
THE LOW WILL CONTINUE TO TRACK EAST ACROSS THE EASTERN LAKES THROUGH
THIS EVENING...WITH THE FRONT PUSHING SOUTHEAST OF LAKE MICHIGAN
LATER THIS MORNING. WEAK HIGH PRESSURE RIDGING WILL THEN MOVE ACROSS
THE WESTERN LAKES LATER TODAY/TONIGHT...DRIFTING SLOWLY OFF TO THE
EAST ON MONDAY. WITH A RELATIVELY WEAK PUSH TO THE FRONT TODAY...
WINDS WILL SHIFT TO THE NORTH AT GENERALLY LESS THAN 15 KT.
FORECAST MODELS CONTINUE TO DEPICT AN AREA OF LOW PRESSURE
DEVELOPING ACROSS THE HIGH PLAINS BY EARLY MONDAY...WHICH THEN
DEEPENS ACROSS THE CENTRAL PLAINS MONDAY NIGHT. VARIOUS MODEL
SOLUTIONS CONTINUE TO SHOW DIFFERENCES WITH THE EVOLUTION OF THIS
LOW THROUGH MID-WEEK...THOUGH THERE IS SOME CONSENSUS IN LIFTING THE
LOW NORTHEAST ACROSS THE NORTHERN GREAT LAKES WEDNESDAY. GENERALLY
HAVE CONTINUED TO FOLLOW THE SLOWER SOLUTIONS OF THE ECMWF/GEM/UKMET
WITH THIS SYSTEM...THOUGH WILL HAVE TO SEE SOME OF THE DIFFERENCES
IRONED OUT BEFORE CONFIDENCE INCREASES IN DETAILS OF STRENGTH/TRACK
AND TIMING. IT DOES APPEAR THAT THE POTENTIAL EXISTS FOR SOUTHEAST
30-35 KT WINDS AHEAD OF THE LOW LATE TUESDAY INTO WEDNESDAY...AND
WEST GALES LATER WEDNESDAY INTO THURSDAY WITH THE PASSAGE OF THIS
STORM. STILL 3-4 DAYS OUT SO WILL NOT HAVE ANY HEADLINES...THOUGH
WILL MENTION POSSIBLE GALES IN FORECAST FOR THIS PERIOD.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
248 AM CST Sun Dec 1 2013
.DISCUSSION...
ISSUED 248 AM CST Sun Dec 1 2013
Main forecast challenge focuses on departing storm system for the
middle and end of the week...and whether or not it will produce
any wintry precipitation across central Illinois.
SHORT TERM...Today through Tuesday
Weak cold front currently across northern Illinois will sink
southward today, eventually becoming stationary along the Ohio
River by evening. Front will be accompanied by little in the way
of sensible weather other than a shift in the wind. Low-level
moisture seen on IR/fog satellite across southeast Missouri/far
southern Illinois is progged by HRRR to remain mostly south of
I-70 today, while patchy mid-level clouds over Iowa into far
northern Illinois stay mostly north of the area. End result will
be mostly sunny skies until later this afternoon when clouds begin
to approach from the northwest. High temperatures will be bit
cooler behind the cold front, ranging from the middle 40s far
northwest around Galesburg to the lower 50s south of I-70.
Boundary will remain in place along the Ohio River through Monday,
before lifting back northward in response to rising upper-level
heights Monday night into Tuesday. Models continue to show a
subtle short-wave rippling eastward out of the Plains late Sunday
night into Monday that could interact with the front to produce
scattered light showers. Forecast soundings remain dry at
low-levels: however, think forcing will be strong enough to
mention a slight chance for showers on Monday. As front lifts
northward, rain chances will shift into the southern Great Lakes
on Tuesday. Brisk southerly winds south of the departing warm
front will bring much warmer air into the region, with Tuesday
afternoon highs reaching the lower to middle 50s.
LONG TERM...Wednesday through Saturday
Forecast becomes more challenging in the extended, as upper low
currently over northwest British Columbia drops southward and
carves a deep trough across the western CONUS by the middle of the
week. Downstream ridging will place the Midwest/Great Lakes in a
broad southwesterly flow pattern, leading to increased precip
chances Wednesday into Thursday. Models have been struggling with
the evolution of a surface low pressure system and its associated
cold front for the past several runs: however, the 00z DEC 1 run
seems to be coming into better agreement. While GFS remains a fast
outlier, the latest ECMWF has sped up the front quite a bit.
Following an ECMWF/GEM consensus yields FROPA across central
Illinois on Wednesday followed by sharply colder conditions for
the end of the week. Main question will be how much precip will
hold back in the colder airmass Thursday and possibly Friday.
Previous runs of the ECMWF had featured quite a bit of wintry
precip Thursday night into Friday as a secondary wave of low
pressure tracked along the departing front. While it still shows the
potential for wintry precip, it has backed off/shifted E/SE with
its latest solution. GEM seems to be the most consistent model
over the past couple of days, so have trended toward its solution.
With cold front passing on Wednesday, will mention a chance for
showers. After FROPA, precip will largely shut off Wednesday
night, before a wave of low pressure tracking from the lower
Mississippi River Valley into the Ohio River Valley brings a
renewed round of precip primarily across the eastern half of the
KILX CWA on Thursday/Thursday night. Have focused highest POPs
along/east of I-57 for both Thursday and Thursday night, tapering
down to just slight chances further west along/west of the
Illinois River. Precip type during the day Thursday will be rain
across the east, with a rain/snow mix along I-55 and mostly light
snow in the Illinois River Valley. As deeper layer of cold air
arrives, precip will change to light snow across the board
Thursday night, with a light accumulation possible. After that,
will hold on to low chance POPs for snow across the far E/SE on
Friday, although if trends continue, these may need to be dropped
entirely. Main weather story for the end of the week will be the
much colder conditions. Highs by Friday and Saturday will only be
in the 20s, with overnight lows in the single digits and teens.
Barnes
&&
.AVIATION...
ISSUED 1118 PM CST Sat Nov 30 2013
VFR conditions will prevail at all sites next 24hrs. Becoming
increasing obvious that light fog will not be developing
overnight. However, still thinking there is some lower level
moisture there and that some light fog still possible, but only as
a TEMPO group in the early morning hours from about 10-13z. Also
vis will not drop that much so TEMPO vis will be MVFR at 3-5SM.
Besides that, skies will be clear overnight and through tomorrow.
Then mid clouds around 12kft will advect into the area for the
evening hours. A weak front will move through the area overnight,
which should have winds switching to southwest and then west.
However, speeds are so light that variable direction is best
overnight. Then winds should be north to northwest after FROPA and
then become northeast during the evening hours.
Auten
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
244 PM EST SUN DEC 1 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM EST SUN DEC 1 2013
A WEAK COLD FRONT WILL MOVE INTO THE REGION FROM THE NORTH LATER
TODAY...EVENTUALLY STALLING OUT NEAR THE OHIO RIVER EARLY MONDAY
BEFORE RETURNING NORTH AS A WARM FRONT. CLOUDS WILL INCREASE TODAY
AND TONIGHT...WITH A FEW RAIN SHOWERS DEVELOP ON MONDAY AS THE FRONT
LIFTS BACK NORTH. STRONG LOW PRESSURE WILL TRACK INTO THE GREAT
LAKES BY LATE WEDNESDAY...WITH A TRAILING COLD FRONT CROSSING
THROUGH THE OHIO VALLEY INTO WEDNESDAY NIGHT AND THURSDAY AND
BRINGING RAIN TO THE REGION. MUCH COLDER AIR WILL SPILL INTO CENTRAL
INDIANA BEHIND THE FRONT...WITH THE POTENTIAL FOR PRECIPITATION TO
END AS SNOW LATE WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1005 AM EST SUN DEC 1 2013
EXTENSIVE AREA OF STRATUS WAS ALONG AND SOUTH OF A VINCENNES TO
GREENSBURG LINE WHILE MOSTLY CLEAR CONDITIONS WERE TO THE NORTH.
HOWEVER AN AREA OF HIGH CLOUDS WAS SPREADING INTO OUR FAR NORTH.
A WEAK AND DIFFUSE COLD FRONT WILL MOVE SOUTH ACROSS OUR REGION AND
STALL OVER SOUTH CENTRAL SECTIONS BY THIS EVENING.
THE MAIN CHANGES TO THIS FORECAST WILL BE TO REDUCE CLOUD COVER AS
STRATUS TO OUR SOUTH HAS SHOWN NO PROGRESSION NORTHWARD AND RUC
SOUNDINGS INDICATE THIS COULD BREAK UP LATER TODAY. EXPECT MOST
AREAS NORTH AND CENTRAL TO START OUT MOSTLY SUNNY WITH PARTLY CLOUDY
CONDITIONS ALL AREAS LATE TODAY.
GIVEN THAT THERE WILL BE MORE SUNSHINE THAN PREVIOUSLY EXPECTED AND
BASED ON RUC 2 METER TEMPERATURES...WILL RAISE HIGH TEMPERATURES
TODAY ABOUT 3 DEGREES THAN WHAT PREVIOUSLY FORECASTED.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 329 AM EST SUN DEC 1 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES WITH THE BOUNDARY IN THE
REGION LATE TONIGHT INTO EARLY TUESDAY.
THE FRONT WILL BECOME NEARLY STATIONARY ACROSS THE REGION TONIGHT
INTO EARLY MONDAY AS A BROADER WAVE ALOFT TRACKS OUT OF THE CENTRAL
PLAINS AND INTO THE OHIO AND TENNESSEE VALLEYS BY MONDAY MORNING.
MODEL SOUNDINGS INDICATING THE DEVELOPMENT OF A SHARP BUT SHALLOW
INVERSION IN THE LOWEST 1-2KFT OVERNIGHT WITH THE LIKELIHOOD OF A
LOW STRATUS DECK BECOMING WELL ESTABLISHED. HOWEVER WITH DRIER AIR
PRESENT FURTHER UP THROUGH THE BOUNDARY LAYER...THINK THE MOIST
LAYER WILL REMAIN TOO SHALLOW TO SUPPORT ANY
PRECIP/DRIZZLE/SPRINKLES OVERNIGHT...AND HAVE REMOVED PRECIP
CHANCES THROUGH DAYBREAK MONDAY.
BEST CHANCE FOR A FEW RAIN SHOWERS LIKELY COMES MONDAY WITH SLIGHTLY
BETTER FORCING ALOFT COURTESY OF THE AFOREMENTIONED UPPER WAVE AND
PRESENCE OF DEEPER MOISTURE. LOWER LEVELS SHOULD WARM ENOUGH TO
ALLOW PRECIP TO FALL AS ALL RAIN OVER FAR NORTHERN COUNTIES MONDAY
MORNING. RAINFALL AMOUNTS WILL BE ONLY A FEW HUNDREDTHS AT BEST AND
THE SPARSE NATURE OF THE RAIN SHOWERS WILL MEAN SOME LOCATIONS
PROBABLY SEE NO PRECIP AT ALL. WILL MAINTAIN ONLY LOW CHANCE POPS
INTO MONDAY EVENING.
THE FRONT WILL LIFT NORTH OF THE REGION LATE MONDAY NIGHT IN
RESPONSE TO LOW PRESSURE EJECTING OUT OF THE PACIFIC NORTHWEST AND
INTO THE NORTHERN PLAINS BY TUESDAY MORNING. GUIDANCE CONTINUING TO
VARY ON THE HANDLING OF THE SHARP POLAR VORTEX DIVING THROUGH THE
NORTHERN ROCKIES AND THE OVERALL COMPLEX NATURE OF THE UPPER LEVEL
FLOW. ONE TREND NOTED OVER THE LAST FEW MODEL RUNS HOWEVER IS A
GENERAL CONSENSUS TOWARDS A FASTER EASTWARD PROGRESSION TO THE
SURFACE WAVE AND ASSOCIATED COLD FRONT. THE OP GFS IS MOST
PROGRESSIVE AND HAS SUPPORT FROM ITS ENSEMBLE MEMBERS...BUT APPEARS
TO DAMPEN DOWNSTREAM UPPER RIDGING TOO QUICKLY. PREFER THE GROWING
CONSENSUS PRESENTED BY THE OTHER MODELS WITH THE COLD FRONT QUICKLY
APPROACHING THE MISSISSIPPI VALLEY BY WEDNESDAY MORNING. COULD SEE
RAIN SHOWERS DEVELOP AS EARLY AS TUESDAY NIGHT AS A LOW LEVEL JET
MOVES INTO THE OHIO VALLEY.
TEMPS...UNDERCUT AGGRESSIVE MOS GUIDANCE OVERALL FOR MONDAY HIGHS
WITH PRESENCE OF CLOUDS AND PRECIP LIKELY LIMITING WARMING. THE
EXPANSION OF STRONG WARM ADVECTION SOUTH OF THE WARM FRONT ON
TUESDAY SETTING THE STAGE FOR A MILD DAY EVEN DESPITE EXPECTED CLOUD
COVER. MOS AGAIN LOOKED SOMEWHAT AGGRESSIVE...BUT A SEVERAL DEGREE
BUMP IN TEMPS IS WARRANTED WITH THE ENTIRE AREA INTO THE MID/UPPER
50S. CLOSER TO THE WARMER MAVMOS TONIGHT WITH CLOUDS...THEN NEAR
MOS FOR LOWS MONDAY/TUESDAY NIGHTS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 244 PM EST SUN DEC 1 2013
PLENTY OF UNCERTAINTY ON HOW FAST COLD AIR WILL ARRIVE INTO THE AREA
DURING THE EARLY PART OF THE LONG TERM. LATEST TREND HAS BEEN FOR A
QUICKER ARRIVAL...ALTHOUGH A VERY QUICK LOOK AT THE 12Z ECMWF SHOWS
THAT IT HAS DECIDED TO BE A LITTLE SLOWER ONCE AGAIN.
SINCE PREVIOUS FORECAST WAS SO WARM DUE TO SLOWER TIMING...DECIDED
TO GO A LITTLE COOLER THAN ALLBLEND EARLY IN THE EXTENDED. OTHERWISE
GENERALLY STAYED WITH ALLBLEND.
A COUPLE OF WAVES OF LOW PRESSURE WILL RIDE ALONG A FRONT TO OUR
EAST DURING THE FIRST HALF OF THE LONG TERM. WITH THE EXPECTED
THERMAL PROFILES...EXPECT A MIX OF RAIN AND SNOW THURSDAY WITH
MAINLY SNOW ON FRIDAY. COULD BE SOME LOW ACCUMULATIONS OF SNOW.
AS STATED EARLIER THOUGH...UNCERTAINTY IS HIGH SO FORECAST COULD
CHANGE SIGNIFICANTLY DEPENDING ON SPEED OF COLD AIR AND WHERE FRONT
ENDS UP.
SECOND HALF OF LONG TERM LOOKS COLD AND DRY AS ARCTIC AIR SETTLES
IN.
&&
.AVIATION /DISCUSSION FOR THE 011800Z TAF ISSUANCE/...
ISSUED AT 1150 AM EST SUN DEC 1 2013
VFR CONDITIONS THIS AFTERNOON WILL GIVE WAY TO MVFR OVERNIGHT.
COLD FRONT IS MOVING INTO CENTRAL INDIANA NOW AND WILL SHIFT WINDS
TO WEST THEN NORTHWEST THROUGH THE AFTERNOON. WIND SPEEDS WILL BE
LESS THAN 10KT. LOOKS LIKE MAINLY MID CLOUD WILL BE ASSOCIATED WITH
THE FRONT.
UNCERTAINTY INCREASES FOR THE EVENING INTO THE OVERNIGHT PERIOD.
FRONT WILL STALL OUT JUST SOUTH OF THE TAF SITES ALLOWING MOISTURE
TO BEGIN TO POOL ALONG IT. THIS SHOULD EVENTUALLY CREATE SOME FOG
AND MVFR CEILINGS. TIMING AND COVERAGE IS UNCERTAIN SO FOR NOW KEPT
AROUND 08Z AS START TIME FOR LOWER CONDITIONS.
LOWER CONDITIONS SHOULD PERSIST THROUGH MONDAY MORNING WITH FRONT
REMAINING IN THE AREA.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...JH
SHORT TERM...RYAN
LONG TERM....50
AVIATION...50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1150 AM EST SUN DEC 1 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM EST SUN DEC 1 2013
A WEAK COLD FRONT WILL MOVE INTO THE REGION FROM THE NORTH LATER
TODAY...EVENTUALLY STALLING OUT NEAR THE OHIO RIVER EARLY MONDAY
BEFORE RETURNING NORTH AS A WARM FRONT. CLOUDS WILL INCREASE TODAY
AND TONIGHT...WITH A FEW RAIN SHOWERS DEVELOP ON MONDAY AS THE FRONT
LIFTS BACK NORTH. STRONG LOW PRESSURE WILL TRACK INTO THE GREAT
LAKES BY LATE WEDNESDAY...WITH A TRAILING COLD FRONT CROSSING
THROUGH THE OHIO VALLEY INTO WEDNESDAY NIGHT AND THURSDAY AND
BRINGING RAIN TO THE REGION. MUCH COLDER AIR WILL SPILL INTO CENTRAL
INDIANA BEHIND THE FRONT...WITH THE POTENTIAL FOR PRECIPITATION TO
END AS SNOW LATE WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1005 AM EST SUN DEC 1 2013
EXTENSIVE AREA OF STRATUS WAS ALONG AND SOUTH OF A VINCENNES TO
GREENSBURG LINE WHILE MOSTLY CLEAR CONDITIONS WERE TO THE NORTH.
HOWEVER AN AREA OF HIGH CLOUDS WAS SPREADING INTO OUR FAR NORTH.
A WEAK AND DIFFUSE COLD FRONT WILL MOVE SOUTH ACROSS OUR REGION AND
STALL OVER SOUTH CENTRAL SECTIONS BY THIS EVENING.
THE MAIN CHANGES TO THIS FORECAST WILL BE TO REDUCE CLOUD COVER AS
STRATUS TO OUR SOUTH HAS SHOWN NO PROGRESSION NORTHWARD AND RUC
SOUNDINGS INDICATE THIS COULD BREAK UP LATER TODAY. EXPECT MOST
AREAS NORTH AND CENTRAL TO START OUT MOSTLY SUNNY WITH PARTLY CLOUDY
CONDITIONS ALL AREAS LATE TODAY.
GIVEN THAT THERE WILL BE MORE SUNSHINE THAN PREVIOUSLY EXPECTED AND
BASED ON RUC 2 METER TEMPERATURES...WILL RAISE HIGH TEMPERATURES
TODAY ABOUT 3 DEGREES THAN WHAT PREVIOUSLY FORECASTED.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 329 AM EST SUN DEC 1 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES WITH THE BOUNDARY IN THE
REGION LATE TONIGHT INTO EARLY TUESDAY.
THE FRONT WILL BECOME NEARLY STATIONARY ACROSS THE REGION TONIGHT
INTO EARLY MONDAY AS A BROADER WAVE ALOFT TRACKS OUT OF THE CENTRAL
PLAINS AND INTO THE OHIO AND TENNESSEE VALLEYS BY MONDAY MORNING.
MODEL SOUNDINGS INDICATING THE DEVELOPMENT OF A SHARP BUT SHALLOW
INVERSION IN THE LOWEST 1-2KFT OVERNIGHT WITH THE LIKELIHOOD OF A
LOW STRATUS DECK BECOMING WELL ESTABLISHED. HOWEVER WITH DRIER AIR
PRESENT FURTHER UP THROUGH THE BOUNDARY LAYER...THINK THE MOIST
LAYER WILL REMAIN TOO SHALLOW TO SUPPORT ANY
PRECIP/DRIZZLE/SPRINKLES OVERNIGHT...AND HAVE REMOVED PRECIP
CHANCES THROUGH DAYBREAK MONDAY.
BEST CHANCE FOR A FEW RAIN SHOWERS LIKELY COMES MONDAY WITH SLIGHTLY
BETTER FORCING ALOFT COURTESY OF THE AFOREMENTIONED UPPER WAVE AND
PRESENCE OF DEEPER MOISTURE. LOWER LEVELS SHOULD WARM ENOUGH TO
ALLOW PRECIP TO FALL AS ALL RAIN OVER FAR NORTHERN COUNTIES MONDAY
MORNING. RAINFALL AMOUNTS WILL BE ONLY A FEW HUNDREDTHS AT BEST AND
THE SPARSE NATURE OF THE RAIN SHOWERS WILL MEAN SOME LOCATIONS
PROBABLY SEE NO PRECIP AT ALL. WILL MAINTAIN ONLY LOW CHANCE POPS
INTO MONDAY EVENING.
THE FRONT WILL LIFT NORTH OF THE REGION LATE MONDAY NIGHT IN
RESPONSE TO LOW PRESSURE EJECTING OUT OF THE PACIFIC NORTHWEST AND
INTO THE NORTHERN PLAINS BY TUESDAY MORNING. GUIDANCE CONTINUING TO
VARY ON THE HANDLING OF THE SHARP POLAR VORTEX DIVING THROUGH THE
NORTHERN ROCKIES AND THE OVERALL COMPLEX NATURE OF THE UPPER LEVEL
FLOW. ONE TREND NOTED OVER THE LAST FEW MODEL RUNS HOWEVER IS A
GENERAL CONSENSUS TOWARDS A FASTER EASTWARD PROGRESSION TO THE
SURFACE WAVE AND ASSOCIATED COLD FRONT. THE OP GFS IS MOST
PROGRESSIVE AND HAS SUPPORT FROM ITS ENSEMBLE MEMBERS...BUT APPEARS
TO DAMPEN DOWNSTREAM UPPER RIDGING TOO QUICKLY. PREFER THE GROWING
CONSENSUS PRESENTED BY THE OTHER MODELS WITH THE COLD FRONT QUICKLY
APPROACHING THE MISSISSIPPI VALLEY BY WEDNESDAY MORNING. COULD SEE
RAIN SHOWERS DEVELOP AS EARLY AS TUESDAY NIGHT AS A LOW LEVEL JET
MOVES INTO THE OHIO VALLEY.
TEMPS...UNDERCUT AGGRESSIVE MOS GUIDANCE OVERALL FOR MONDAY HIGHS
WITH PRESENCE OF CLOUDS AND PRECIP LIKELY LIMITING WARMING. THE
EXPANSION OF STRONG WARM ADVECTION SOUTH OF THE WARM FRONT ON
TUESDAY SETTING THE STAGE FOR A MILD DAY EVEN DESPITE EXPECTED CLOUD
COVER. MOS AGAIN LOOKED SOMEWHAT AGGRESSIVE...BUT A SEVERAL DEGREE
BUMP IN TEMPS IS WARRANTED WITH THE ENTIRE AREA INTO THE MID/UPPER
50S. CLOSER TO THE WARMER MAVMOS TONIGHT WITH CLOUDS...THEN NEAR
MOS FOR LOWS MONDAY/TUESDAY NIGHTS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ISSUED AT 329 AM EST SUN DEC 1 2013
ENSEMBLES ARE IN GOOD AGREEMENT ON THE EVOLVING WEATHER PATTERN
LATER THIS WEEK. MEAN UPPER TROUGHING EXPECTED FROM THE NORTHERN
PLAINS BACK INTO THE SOUTHWEST...WHILE UPPER RIDGING DEVELOPS OVER
THE SOUTHEAST. THIS WILL RESULT IN SOUTHWESTERLY UPPER FLOW LOCALLY.
APPEARS A DECENT CHUNK OF ENERGY WILL EJECT OUT OF THE WESTERN
TROUGH INTO WESTERN GREAT LAKES AROUND WEDNESDAY. WILL KEEP SOME
RAIN CHANCES IN THE FORECAST FOR WEDNESDAY AS THE UPPER DISTURBANCE
MOVES THROUGH.
AFTER THAT...FORECAST BECOMES MORE MUDDLED AS THE POTENTIAL EXISTS
FOR WAVES TO EJECT OUT OF THE WESTERN TROUGH. AT THIS POINT...THE
ENSEMBLES DON/T INDICATE ANY MAJOR LOW PRESSURE SYSTEMS...BUT RATHER
STABLE TYPE SURFACE WAVES RIPPLING ALONG A PRIMARY FRONTAL ZONE
LOCATED OVER THE TENNESSEE VALLEY. ENSEMBLES SEEM TO KEY IN ON ONE
WAVE MOVING THROUGH AROUND THURSDAY INTO EARLY FRIDAY...AND ANOTHER
JUST AFTER THIS FORECAST PERIOD. ALTHOUGH AN ARGUMENT CAN BE MADE
FOR AT LEAST SOME PRECIPITATION THREAT EVERY DAY...FOR NOW WILL KEEP
THE POPS RESTRICTED TO THURSDAY AND FRIDAY. APPEARS THERE IS
POTENTIAL FOR SOME LIGHT SNOW ACCUMULATIONS THURSDAY NIGHT INTO
FRIDAY MORNING.
&&
.AVIATION /DISCUSSION FOR THE 011800Z TAF ISSUANCE/...
ISSUED AT 1150 AM EST SUN DEC 1 2013
VFR CONDITIONS THIS AFTERNOON WILL GIVE WAY TO MVFR OVERNIGHT.
COLD FRONT IS MOVING INTO CENTRAL INDIANA NOW AND WILL SHIFT WINDS
TO WEST THEN NORTHWEST THROUGH THE AFTERNOON. WIND SPEEDS WILL BE
LESS THAN 10KT. LOOKS LIKE MAINLY MID CLOUD WILL BE ASSOCIATED WITH
THE FRONT.
UNCERTAINTY INCREASES FOR THE EVENING INTO THE OVERNIGHT PERIOD.
FRONT WILL STALL OUT JUST SOUTH OF THE TAF SITES ALLOWING MOISTURE
TO BEGIN TO POOL ALONG IT. THIS SHOULD EVENTUALLY CREATE SOME FOG
AND MVFR CEILINGS. TIMING AND COVERAGE IS UNCERTAIN SO FOR NOW KEPT
AROUND 08Z AS START TIME FOR LOWER CONDITIONS.
LOWER CONDITIONS SHOULD PERSIST THROUGH MONDAY MORNING WITH FRONT
REMAINING IN THE AREA.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...JH
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1005 AM EST SUN DEC 1 2013
.UPDATE...
NEAR TERM FOR THE REST OF TODAY HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM EST SUN DEC 1 2013
A WEAK COLD FRONT WILL MOVE INTO THE REGION FROM THE NORTH LATER
TODAY...EVENTUALLY STALLING OUT NEAR THE OHIO RIVER EARLY MONDAY
BEFORE RETURNING NORTH AS A WARM FRONT. CLOUDS WILL INCREASE TODAY
AND TONIGHT...WITH A FEW RAIN SHOWERS DEVELOP ON MONDAY AS THE FRONT
LIFTS BACK NORTH. STRONG LOW PRESSURE WILL TRACK INTO THE GREAT
LAKES BY LATE WEDNESDAY...WITH A TRAILING COLD FRONT CROSSING
THROUGH THE OHIO VALLEY INTO WEDNESDAY NIGHT AND THURSDAY AND
BRINGING RAIN TO THE REGION. MUCH COLDER AIR WILL SPILL INTO CENTRAL
INDIANA BEHIND THE FRONT...WITH THE POTENTIAL FOR PRECIPITATION TO
END AS SNOW LATE WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1005 AM EST SUN DEC 1 2013
EXTENSIVE AREA OF STRATUS WAS ALONG AND SOUTH OF A VINCENNES TO
GREENSBURG LINE WHILE MOSTLY CLEAR CONDITIONS WERE TO THE NORTH.
HOWEVER AN AREA OF HIGH CLOUDS WAS SPREADING INTO OUR FAR NORTH.
A WEAK AND DIFFUSE COLD FRONT WILL MOVE SOUTH ACROSS OUR REGION AND
STALL OVER SOUTH CENTRAL SECTIONS BY THIS EVENING.
THE MAIN CHANGES TO THIS FORECAST WILL BE TO REDUCE CLOUD COVER AS
STRATUS TO OUR SOUTH HAS SHOWN NO PROGRESSION NORTHWARD AND RUC
SOUNDINGS INDICATE THIS COULD BREAK UP LATER TODAY. EXPECT MOST
AREAS NORTH AND CENTRAL TO START OUT MOSTLY SUNNY WITH PARTLY CLOUDY
CONDITIONS ALL AREAS LATE TODAY.
GIVEN THAT THERE WILL BE MORE SUNSHINE THAN PREVIOUSLY EXPECTED AND
BASED ON RUC 2 METER TEMPERATURES...WILL RAISE HIGH TEMPERATURES
TODAY ABOUT 3 DEGREES THAN WHAT PREVIOUSLY FORECASTED.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 329 AM EST SUN DEC 1 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES WITH THE BOUNDARY IN THE
REGION LATE TONIGHT INTO EARLY TUESDAY.
THE FRONT WILL BECOME NEARLY STATIONARY ACROSS THE REGION TONIGHT
INTO EARLY MONDAY AS A BROADER WAVE ALOFT TRACKS OUT OF THE CENTRAL
PLAINS AND INTO THE OHIO AND TENNESSEE VALLEYS BY MONDAY MORNING.
MODEL SOUNDINGS INDICATING THE DEVELOPMENT OF A SHARP BUT SHALLOW
INVERSION IN THE LOWEST 1-2KFT OVERNIGHT WITH THE LIKELIHOOD OF A
LOW STRATUS DECK BECOMING WELL ESTABLISHED. HOWEVER WITH DRIER AIR
PRESENT FURTHER UP THROUGH THE BOUNDARY LAYER...THINK THE MOIST
LAYER WILL REMAIN TOO SHALLOW TO SUPPORT ANY
PRECIP/DRIZZLE/SPRINKLES OVERNIGHT...AND HAVE REMOVED PRECIP
CHANCES THROUGH DAYBREAK MONDAY.
BEST CHANCE FOR A FEW RAIN SHOWERS LIKELY COMES MONDAY WITH SLIGHTLY
BETTER FORCING ALOFT COURTESY OF THE AFOREMENTIONED UPPER WAVE AND
PRESENCE OF DEEPER MOISTURE. LOWER LEVELS SHOULD WARM ENOUGH TO
ALLOW PRECIP TO FALL AS ALL RAIN OVER FAR NORTHERN COUNTIES MONDAY
MORNING. RAINFALL AMOUNTS WILL BE ONLY A FEW HUNDREDTHS AT BEST AND
THE SPARSE NATURE OF THE RAIN SHOWERS WILL MEAN SOME LOCATIONS
PROBABLY SEE NO PRECIP AT ALL. WILL MAINTAIN ONLY LOW CHANCE POPS
INTO MONDAY EVENING.
THE FRONT WILL LIFT NORTH OF THE REGION LATE MONDAY NIGHT IN
RESPONSE TO LOW PRESSURE EJECTING OUT OF THE PACIFIC NORTHWEST AND
INTO THE NORTHERN PLAINS BY TUESDAY MORNING. GUIDANCE CONTINUING TO
VARY ON THE HANDLING OF THE SHARP POLAR VORTEX DIVING THROUGH THE
NORTHERN ROCKIES AND THE OVERALL COMPLEX NATURE OF THE UPPER LEVEL
FLOW. ONE TREND NOTED OVER THE LAST FEW MODEL RUNS HOWEVER IS A
GENERAL CONSENSUS TOWARDS A FASTER EASTWARD PROGRESSION TO THE
SURFACE WAVE AND ASSOCIATED COLD FRONT. THE OP GFS IS MOST
PROGRESSIVE AND HAS SUPPORT FROM ITS ENSEMBLE MEMBERS...BUT APPEARS
TO DAMPEN DOWNSTREAM UPPER RIDGING TOO QUICKLY. PREFER THE GROWING
CONSENSUS PRESENTED BY THE OTHER MODELS WITH THE COLD FRONT QUICKLY
APPROACHING THE MISSISSIPPI VALLEY BY WEDNESDAY MORNING. COULD SEE
RAIN SHOWERS DEVELOP AS EARLY AS TUESDAY NIGHT AS A LOW LEVEL JET
MOVES INTO THE OHIO VALLEY.
TEMPS...UNDERCUT AGGRESSIVE MOS GUIDANCE OVERALL FOR MONDAY HIGHS
WITH PRESENCE OF CLOUDS AND PRECIP LIKELY LIMITING WARMING. THE
EXPANSION OF STRONG WARM ADVECTION SOUTH OF THE WARM FRONT ON
TUESDAY SETTING THE STAGE FOR A MILD DAY EVEN DESPITE EXPECTED CLOUD
COVER. MOS AGAIN LOOKED SOMEWHAT AGGRESSIVE...BUT A SEVERAL DEGREE
BUMP IN TEMPS IS WARRANTED WITH THE ENTIRE AREA INTO THE MID/UPPER
50S. CLOSER TO THE WARMER MAVMOS TONIGHT WITH CLOUDS...THEN NEAR
MOS FOR LOWS MONDAY/TUESDAY NIGHTS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ISSUED AT 329 AM EST SUN DEC 1 2013
ENSEMBLES ARE IN GOOD AGREEMENT ON THE EVOLVING WEATHER PATTERN
LATER THIS WEEK. MEAN UPPER TROUGHING EXPECTED FROM THE NORTHERN
PLAINS BACK INTO THE SOUTHWEST...WHILE UPPER RIDGING DEVELOPS OVER
THE SOUTHEAST. THIS WILL RESULT IN SOUTHWESTERLY UPPER FLOW LOCALLY.
APPEARS A DECENT CHUNK OF ENERGY WILL EJECT OUT OF THE WESTERN
TROUGH INTO WESTERN GREAT LAKES AROUND WEDNESDAY. WILL KEEP SOME
RAIN CHANCES IN THE FORECAST FOR WEDNESDAY AS THE UPPER DISTURBANCE
MOVES THROUGH.
AFTER THAT...FORECAST BECOMES MORE MUDDLED AS THE POTENTIAL EXISTS
FOR WAVES TO EJECT OUT OF THE WESTERN TROUGH. AT THIS POINT...THE
ENSEMBLES DON/T INDICATE ANY MAJOR LOW PRESSURE SYSTEMS...BUT RATHER
STABLE TYPE SURFACE WAVES RIPPLING ALONG A PRIMARY FRONTAL ZONE
LOCATED OVER THE TENNESSEE VALLEY. ENSEMBLES SEEM TO KEY IN ON ONE
WAVE MOVING THROUGH AROUND THURSDAY INTO EARLY FRIDAY...AND ANOTHER
JUST AFTER THIS FORECAST PERIOD. ALTHOUGH AN ARGUMENT CAN BE MADE
FOR AT LEAST SOME PRECIPITATION THREAT EVERY DAY...FOR NOW WILL KEEP
THE POPS RESTRICTED TO THURSDAY AND FRIDAY. APPEARS THERE IS
POTENTIAL FOR SOME LIGHT SNOW ACCUMULATIONS THURSDAY NIGHT INTO
FRIDAY MORNING.
&&
.AVIATION /DISCUSSION FOR THE 011500Z TAF UPDATE/...
ISSUED AT 921 AM EST SUN DEC 1 2013
KIND TAF IS GOOD. ONLY MINOR TWEAKS MADE. LOOKS LIKE KIND WILL
REMAIN IN BETWEEN BKN050 DECK TO THE SOUTHEAST AND BKN150 DECK TO
THE NORTHWEST INTO THE AFTERNOON.
PREVIOUS DISCUSSION FOLLOWS...
VFR CEILINGS AROUND 050 CURRENTLY IN THE KBMG AREA SHOULD SCATTER
OUT BY ISSUANCE TIME.
OTHERWISE...WEAK FRONTAL SYSTEM EXPECTED TO DROP SOUTHEAST ACROSS
THE TAF SITES IN THE 011800Z-020000Z TIME FRAME...ACCOMPANIED BY A
GRADUAL WIND SHIFT TO 320-350 DEGREES. WIND SPEEDS SHOULD GENERALLY
REMAIN UNDER 10 KTS ACROSS THE FRONT.
FRONT SHOULD BE INACTIVE FOR THE MOST PART...OTHER THAN THE FACT
THAT IT WILL HELP PULL DOWN SOME OF THE MVFR CEILINGS AROUND 025
CURRENTLY OVER THE GREAT LAKES LATER THIS AFTERNOON AND EARLY THIS
EVENING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...JH
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...JAS/50
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
612 PM CST MON DEC 2 2013
.SHORT TERM /TONIGHT/...
ISSUED AT 424 PM CST MON DEC 2 2013
SKIES ARE CLEARING RAPIDLY FROM WEST TO EAST THIS AFTERNOON...BUT
SOME HIGH CLOUDS ARE FILLING BACK IN FROM THE NORTHWEST PER
SATELLITE IMAGERY. AS EXPECTED A WARM FRONT HAS NOSED INTO OUR SOUTH
AND SOUTHWEST AND CONTINUES TO ADVANCE TOWARD CENTRAL
IOWA...BRINGING TEMPERATURES IN THE 50S WITH IT. A QUIET NIGHT IS IN
STORE AS WINDS REMAIN GENERALLY FROM THE SOUTHEAST BUT MID/HIGH
CLOUDS STEADILY THICKEN AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM.
THIS WILL RESULT IN TEMPERATURES STAYING RELATIVELY WARM IN THE MID
TO UPPER 30S IN MOST AREAS OVERNIGHT. FORECAST SOUNDINGS ALSO
INDICATE THAT BY SUNRISE TUESDAY THERE WILL BE QUITE A DEEP
SATURATED LAYER ASSOCIATED WITH THE MID/HIGH CLOUDS...HOWEVER A
POWERFUL NEAR SURFACE DRY LAYER WILL REMAIN IN PLACE. THIS SHOULD
RESULT IN A SCENARIO SIMILAR TO THIS MORNING WHEREBY ANY PRECIP THAT
FORMS LATE TONIGHT WILL FALL IN THE FORM OF VIRGA EVAPORATING BEFORE
IT HITS THE SURFACE...THEN DURING THE DAY TUESDAY PRECIP WILL BE
MORE LIKELY TO REACH THE GROUND AT TIMES. THUS HAVE REMOVED POPS
OVERNIGHT...ALTHOUGH SPRINKLE WORDING MAY NEED TO BE INTRODUCED
LATER FOR THE PRE DAWN HOURS.
.LONG TERM /TUESDAY THROUGH MONDAY/...
ISSUED AT 424 PM CST MON DEC 2 2013
MAJOR CHALLENGE IN NEAR TERM IS TRACK OF LOW AND LOCATION/TIMING OF
ASSOCIATED FROPA. THE RAP HAS BEEN INITIALIZING THE BEST ALL
MORNING. BY TUESDAY AFTERNOON...GFS A LITTLE FASTER THAN RAP...AND
NAM A LITTLE SLOWER AND FURTHER SOUTH. ECMWF SEEMS TO SOMEWHAT OF AN
OUTLIER ON TRACK OF LOW. IT SEEMS THE NAM HAS THE BEST HANDLE ON THE
SITUATION...SO PUSHING BACK TIME OF COLD FROPA AND HAVE SUBSEQUENTLY
INCREASED TEMPS OVER GUIDANCE AND PREVIOUS FORECAST.
ADDITIONALLY...THERE COULD BE SOME SUNSHINE IN SOUTHWESTERN IOWA
AS DRIER AIR BEING ADVECTED INTO LOWER LEVELS...WHICH COULD
ACTUALLY HELP TEMPS WARM UP INTO THE MID 60S. DECENT MOISTURE
CONVERGENCE AND FORCING ALONG COLD FRONT. HOWEVER...SOUNDING
PROFILES NOT VERY SATURATED IN DMX CWA SO PRECIP MAY STRUGGLE TO
REACH GROUND...THUS LOW QPF FORECAST. STRONG CAA AND TEMP GRADIENT
BEHIND FRONT...SO PRECIP TYPE WILL BE TOUGH TO PIN DOWN. THE
TRANSITION ZONE FROM RAIN TO SNOW WILL BE VERY NARROW. BETTER
FORCING TOWARDS MINNESOTA...SO HIGHER POPS TO THE NORTH.
FOR THURSDAY...GFS SOUNDINGS NOW KEEP THE PROFILE VERY SATURATED
DURING THE MORNING. A FEW FLURRIES MAY FALL DURING THE MORNING...BUT
NOT A LOT OF SUPPORT IN THE ATMOSPHERE FOR ANYTHING THAT WOULD
NOTABLY IMPACT THE PUBLIC. ALL MODELS HAVE SUBSIDENCE AND DRY
NORTHWESTERLY FLOW BEING ADVECTED DOWN TO CWA...ESPECIALLY THE
NAM...DURING THE AFTERNOON. THEREFORE...THINK CLOUDS SHOULD BEGIN
TO BREAK UP DURING THE DAY. DUE TO LACK OF FORCING HAVE REDUCED
POPS FOR THURSDAY PM.
THURSDAY/S TEMPERATURES SLIGHTLY TRICKY. AS MENTIONED ABOVE...CLOUDS
COVER LIKELY TO BE PRESENT DURING THE MORNING BUT WILL BREAK UP
DURING THE AFTERNOON. ADDITIONALLY...IT APPEARS WIND SPEEDS WILL
REMAIN NEAR THE 10 TO 15KT RANGE. CAA THROUGHOUT THE DAY AS H850
TEMPS WILL START THE DAY AROUND -10C AND END THE DAY NEAR -13C.
THEREFORE WENT SEVERAL DEGREES ABOVE GUIDANCE FOR THURSDAY
MORNING...AND WILL INCREASE DAYTIME TEMPERATURES A FEW DEGREES WITH
THE ANTICIPATED SUNSHINE. IN LOCATIONS WHERE SUN CANNOT MAKE IT
THROUGH...TEMPS WILL LIKELY HOLD STEADY OR DECREASE DURING THE DAY.
BY FRIDAY MORNING...PRESSURE GRADIENT STILL PRETTY TIGHT IN ADVANCE
OF APPROACHING HIGH SO WINDS WILL STAY AT LEAST AROUND 10 KTS.
THOUGH NOT A PURE RADIATIONAL COOLING NIGHT...WITH H850 TEMPS
APPROACHING -17C...APPARENT TEMPERATURE AT SURFACE WILL APPROACH
ZERO DEGREES...AND MAY EVEN BE BELOW ZERO IN SOME LOCATIONS. SUNNY
SKIES WILL PREVAIL FOR THE AFTERNOON...BUT HIGHS WILL STRUGGLE TO
MAKE IT OUT OF THE TEENS AS NO WAA EXPECTED.
FOR THE WEEKEND...GFS AND EURO CAME INTO SLIGHTLY BETTER AGREEMENT
WITH THEIR 12Z RUNS. HOWEVER...THERE IS STILL QUITE A BIT OF
DISAGREEMENT. BOTH MODELS DEVELOP A SIZABLE TROUGH THAT PUSHES OFF
THE ROCKIES. THE EURO HAS A MUCH MORE SOUTHERLY TRACK...PUTTING THE
REGION INTO SOUTHWESTERLY FLOW AND BRINGING MUCH GREATER CHANCE FOR
WINTRY PRECIP TO THE AREA. THE GFS ENSEMBLES KEEP THE LOW FURTHER
NORTH...KEEPING THE CWA IN WESTERLY TO NORTHWESTERLY FLOW...WHICH
WOULD KEEP COOL...DRY AIR ALOFT AND REDUCE PRECIPITATION CHANCES
FOR DMX.
&&
.AVIATION...03/00Z
ISSUED AT 612 PM CST MON DEC 2 2013
PRIMARY CONCERN WILL BE VSBY/CIG TRENDS INTO TUE. 00Z SURFACE
ANALYSIS SHOWS WARM FRONT BISECTING IA NW-SE WITH PATCHY MVFR
CONDITIONS ALREADY NOTED N AND E OF THE FRONT. WITH LITTLE CHANGE
ANTICIPATED OVERNIGHT...LINGERING LOW LEVEL MOISTURE AND LIGHT
WINDS...EXPECT CONDITIONS TO DETERIORATE DIURNALLY WITH AT LEAST
PATCHY MVFR VSBYS S AND W OF THE FRONT AND LIKELY LIFR CONDITIONS
N AND E /KMCW/KALO/. CONFIDENCE IS RELATIVELY HIGH ON THIS WITH
CONCEPTUAL AND OPERATIONAL MODELS...MOS GUIDANCE AND SEVERAL HI
RES MODELS ALL SUGGESTING SIMILAR OUTCOMES. CONDITIONS MAY IMPROVE
SOMEWHAT WITH INSOLATION TUE...BUT MVFR VSBYS/CIGS WILL LIKELY
LINGER THROUGHOUT THE PERIOD N AND E WITH LITTLE PATTERN CHANGE. SCT
LIGHT SHOWERS MAY CROSS IA OVERNIGHT AS WELL.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...LEE
LONG TERM...KOTENBERG
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS JACKSON KY
351 PM EST SUN DEC 1 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 338 PM EST SUN DEC 1 2013
A BAND OF LOW CLOUDS REMAINS ACROSS THE REGION IN ADVANCE OF A WEAK
COLD FRONT THAT IS BEGINNING TO SLOW DOWN AND STALL OUT. SOME OF
THESE HAVE ERODED A BIT FROM THE SOUTH OR SOUTHEAST AND NORTHWEST
THROUGHOUT THE DAY. THIS HAS LED TO THE COLDEST TEMPERATURES ON
AVERAGE BETWEEN THE HAL ROGERS PARKWAY AND KY HIGHWAY 80 CORRIDOR AND
INTERSTATE 64 CORRIDOR. SOME OF THE DEEPER SHELTERED VALLEYS NEVER
REALLY MIXED OUT AND TEMPERATURES THERE ARE IN THE LOW TO MID 40S
ATTM. OTHERWISE TEMPS WERE NEAR 50 ACROSS MUCH OF THE SOUTHERN CWA
AND HAD NEARED 50 NORTH OF THE INTERSTATE 64 CORRIDOR.
A WEAK DISTURBANCE IS EXPECTED TO MAINLY PASS TO OUR SOUTH LATER
TONIGHT INTO MONDAY MORNING WHILE A MORE NORTHERN SHORTWAVE WILL
PASS TO THE NORTH OF EASTERN KY ON MONDAY AFTERNOON AND EVENING. THIS
WILL LEAD TO A BRIEF DEVELOPMENT OF A SOUTHEASTERN TROUGH BY MONDAY.
THIS TROUGH WILL MOVE ON OFF TO THE EAST WITH SOME WEAK RIDGING
PASSING THROUGH OVER THE SOUTHEASTERN US AND TN VALLEY FOR MON NIGHT
INTO TUE. AT THE END OF THE PERIOD...A TROUGH IS ANTICIPATED TO
EXTEND FROM CENTRAL CANADA INTO THE NORTHERN PLAINS AND THEN
SOUTHWEST INTO THE ROCKIES AND CALIFORNIA WITH MORE OR LESS ZONAL
FLOW IN THE EASTERN CONUS.
AS AT THE SFC...THE BOUNDARY TO OUR NORTHWEST SHOULD STALL NEAR THE
OH RIVER TONIGHT AND INTO MONDAY BEFORE RETURNING NORTH AS A WARM
FRONT LATER ON MONDAY INTO TUESDAY. MODELS INDICATE A GENERAL
GRADUAL INCREASE IN MOISTURE BELOW THE CURRENT CLOUD LAYER
TONIGHT...BUT MEAGER OMEGA AT BEST. UP UNTIL TODAY AT LEAST...MODELS
SEEM TO HAVE BEEN TOO AGGRESSIVE INCREASING LOW LEVEL MOISTURE.
HOWEVER...DEWPOINTS HAVE CREPT UP INTO THE MID TO UPPER 30S IN
WESTERN AND CENTRAL KY AND MIDDLE AND WESTERN TN. THIS LEADS TO
UNCERTAINTY AS TO WHETHER OR NOT THE STRATOCU DECK COULD LOWER LATER
TONIGHT INTO EARLY ON MONDAY AND WHETHER OR NOT THERE COULD BE SOME
PATCHY DRIZZLE AT THAT TIME. THE 12Z NAM AND 12Z GFS HAD SOME LIGHT
SPOTTY QPF WITH THIS LATE TONIGHT OR MONDAY. THE 18Z HRRR ALSO HAD
SOME LIGHT SPOTTY QPF LATER TONIGHT. THE 15Z SREF POPS ARE LOW AND
HAVE TRENDED DOWN SINCE 24 HOURS AGO. OPTED TO GO WITH A 10 POP FOR
PATCHY DRIZZLE IN ALL BUT THE FAR SOUTHEAST LATE TONIGHT AND INTO
MONDAY MORNING AND THEN STAYED CLOSE TO THE PREVIOUS FORECAST FOR
LATER ON MONDAY INTO MONDAY EVENING WITH A SLIGHT CHANCE IN THE FAR
NORTH. THIS LED TO BETTER ISC CONSISTENCY.
WITH LOW CLOUDS EXPECTED FOR MOST...IF NOT ALL OF THE NIGHT...MIN T
TONIGHT WILL BE CONSIDERABLY MILDER IN DEEPER SHELTERED VALLEY
LOCATIONS COMPARED TO RECENT NIGHTS. MIN T SHOULD REMAIN ABOVE
FREEZING IN ALL LOCATIONS. SOME THINNING OF THE CLOUDS IS ANTICIPATED
ON MON AFTERNOON AND TEMPS SHOULD GENERALLY REACH THE LOW TO MID 50S.
MIN T ON MON NIGHT IS A BIT MORE UNCERTAIN...AS SOME OF THE GUIDANCE
SUGGESTS THERE COULD BE WINDOW OF TIME WHERE CLOUDS COULD BE THIN
ENOUGH OR POSSIBLY BRIEFLY CLEAR AND ALLOW A RIDGE/VALLEY TEMP SPLIT
TO DEVELOP IN SOUTHEASTERN VALLEYS. NEVERTHELESS...MIN T ON MON
NIGHT SHOULD ALSO BE ABOVE NORMAL.
OTHERWISE...THE BULK OF THE PERIOD SHOULD BE DRY WITH SOUTHERLY TO
SOUTHWESTERLY LOW LEVEL FLOW INCREASING LATE IN THE PERIOD IN
ADVANCE OF A DEVELOPING MUCH MORE SIGNIFICANT SYSTEM THAT WILL IMPACT
THE REGION FROM MIDWEEK ON. THE 12Z AND 18Z NAM AS WELL AS THE 12Z
ECMWF SUGGEST A STRAY SHOWER MIGHT BE POSSIBLE OVER THE SOUTHWEST ON
TUE IN THE WARM SECTOR...BUT THE OTHER GUIDANCE WAS MORE SUPPORTIVE
OF JUST A CONSIDERABLE AMOUNT OF CLOUDS FROM TIME TO TIME. MUCH OF
THE RECENT MAX T GUIDANCE SUGGESTS TUE WILL BE RATHER MILD...ABOVE
NORMAL AND IF CLOUDS WERE TO THIN FOR A WHILE 60 DEGREES WOULD BE
REACHABLE IN MANY LOCATIONS. TUE TEMPS WERE RAISED A COUPLE OF DEGREES
ON AVERAGE.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 318 PM EST SUN DEC 1 2013
THE UPPER AIR PATTERN OVER THE EASTERN THIRD OF THE CONUS WILL
FEATURE A LARGE STORM SYSTEM TAKING SHAPE OVER THE NORTHERN PLAINS
TO BEGIN THE PERIOD. BOTH THE GFS AND ECMWF MODELS HAVE VERY SIMILAR
SOLUTIONS REGARDING THE STRENGTH AND EVOLUTION OF THIS SYSTEM. THIS
SYSTEM IS PROGGED TO MOVE ACROSS THE UPPER GREAT LAKES REGION
WEDNESDAY NIGHT AND THURSDAY. AS IT DOES SO...A SURFACE COLD FRONT
WILL MOVE INTO THE AREA FROM THE NORTHWEST...AND EVENTUALLY STALL
ACROSS THE OHIO AND UPPER TENNESSEE VALLEY REGIONS FROM THURSDAY
NIGHT THROUGH SUNDAY. WEAK WAVES OF LOW PRESSURE MOVING ALONG THIS
BOUNDARY...COUPLED WITH A STRONG FEED OF MOISTURE OFF THE GULF OF
MEXICO...WILL COMBINE TO BRING A PROLONGED PERIOD OF PRECIPITATION
TO EASTERN KENTUCKY. THE FIRST COUPLE OF DAYS OF THE PERIOD WILL
FEATURE PERSISTENT SOUTHERLY FLOW OFF THE GULF...WITH HIGH
TEMPERATURES IN THE LOWER 60S ON WEDNESDAY...AND IN THE MID TO UPPER
50S ON THURSDAY. THE WARM MOIST AIR OFF THE GULF WILL BRING AN
INCREASE IN CLOUD COVER AS THE FRONT APPROACHES FROM THE WEST. THE
FIRST PRECIPITATION IS EXPECTED TO MOVE INTO THE NORTHWEST PART OF
THE AREA EARLY WEDNESDAY MORNING...AS WARM MOIST AIR BEGINS TO
INTERACT WITH THE LEADING EDGE OF THE APPROACHING COLD FRONT. AS THE
FRONT CONTINUES TO MOVE SLOWLY EASTWARD...PRECIPITATION WILL
INCREASE IN COVERAGE. THE FIRST GOOD CHANCE OF RAIN SHOULD ARRIVE
WEDNESDAY NIGHT...AS THE FRONT MOVES SOUTH OF THE OHIO RIVER. THE
BEST CHANCE FOR PRECIPITATION WILL OCCUR FROM EARLY THURSDAY MORNING
THROUGH EARLY SATURDAY MORNING...AS THE FRONT STALLS OVER THE
REGION. PRECIPITATION CHANCES SHOULD REMAIN IN THE FORECAST THROUGH
SATURDAY NIGHT...AS YET ANOTHER WEAK WAVE OF LOW PRESSURE MOVES
ALONG THE SLUGGISH FRONTAL BOUNDARY.
TEMPERATURES WILL REMAIN WARM ENOUGH TO KEEP PRECIPITATION IN THE
FORM OF RAIN FROM WEDNESDAY THROUGH FRIDAY AFTERNOON. WITH THE FRONT
STALLED OVER THE AREA...AND WITH A STEADY FEED OF MOISTURE OFF THE
GULF OF MEXICO INTERACTING WITH THE FRONT...THERE WILL THE POTENTIAL
FOR LOCALLY HEAVY RAINFALL. ONCE THE FRONT MOVES THROUGH THE
AREA...AND WINDS SHIFT TO THE NORTHWEST AND EVENTUALLY NORTH...SNOW
MAY BEGIN TO MIX WITH THE RAIN...BEGINNING IN THE FAR NORTHWESTERN
PORTION OF THE FORECAST AREA. THE LATEST TIME HEIGHT CROSS SECTIONS
AND SOUNDINGS SUPPORT A MIX OF RAIN AND SNOW FRIDAY NIGHT THROUGH
THE END OF THE DAY ON SATURDAY. IF THE LATEST MODEL DATA HOLDS
TRUE...THERE COULD BE ENOUGH COLD AIR IN PLACE ACROSS THE AREA FROM
EARLY SATURDAY NIGHT THROUGH EARLY SUNDAY AFTERNOON FOR
PRECIPITATION TO CHANGE OVER TO ALL SNOW. IF THIS TURNS OUT TO BE
THE CASE...WE COULD SEE SOME LIGHT SNOW ACCUMULATIONS SATURDAY NIGHT
AND SUNDAY ACROSS EASTERN KENTUCKY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1229 PM EST SUN DEC 1 2013
RETURN FLOW BETWEEN HIGH PRESSURE TO OUR SOUTHEAST AND A WEAK
BOUNDARY CURRENTLY WORKING INTO THE OH VALLEY WILL CONTINUE THROUGH
THE PERIOD...AND MOISTURE WILL CONTINUE TO BE GRADUALLY TRANSPORTED
NORTHEASTWARD INTO THE REGION. THIS WILL LEAD TO A CONSIDERABLE
AMOUNT OF LOW LEVEL (3.5-5KFT AFL) CLOUDS THROUGH THE PERIOD. DUE TO
DRIER AIR IN THE LOWEST LEVELS...THESE CLOUDS SHOULD NOT LOWER BELOW
2KFT AGL...DURING THE 5Z TO 15Z PERIOD PER MODEL FORECAST SOUNDING
AND LAMP DATA. OTHERWISE...VFR CONDITIONS SHOULD PERSIST THROUGH THE
PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JP
LONG TERM...AR
AVIATION...JP
AREA FORECAST DISCUSSION
NWS GRAY ME
1155 AM EST SUN DEC 1 2013
.SYNOPSIS...
WEAK LOW PRESSURE AND AN ASSOCIATED COLD FRONT WILL SLIDE SOUTHEAST
ACROSS THE AREA THROUGH TONIGHT. A SECOND WEAK LOW WILL TRACK
NORTHEAST AND PASS JUST OFFSHORE TONIGHT AND EARLY MONDAY. THESE
TWO SYSTEMS WILL PRODUCE SOME OCCASIONAL LIGHT SNOW INTO TONIGHT,
WITH MIXING OR A CHANGEOVER TO LIGHT RAIN POSSIBLE NEAR THE COAST.
WEAK TROUGHING ALONG THE COAST KEEPS PRECIPITATION NEARBY ON
MONDAY. LOW PRESSURE TRAVELS UP THE ATLANTIC COASTLINE TUESDAY,
SPREADING MORE PRECIPITATION OVER THE REGION THROUGH WEDNESDAY
MORNING. RIDGING BUILDS IN BRIEFLY BEFORE A COLD FRONT CROSSES THE
REGION THURSDAY.
&&
.NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
1155 AM...ONLY MINOR ADJUSTMENTS FOR THIS ESTF UPDATE LARGELY TO
REFLECT THE CURRENT MESONET AND SHORT TERM TRENDS.
PREV DISC...
945 AM...THE COASTAL FRONT IS SETTING UP SHOP JUST OFFSHORE THEN
EXTENDS INTO MY EASTERN ZONES AND TO THE WEST OF ROCKLAND. I
LOWERED MAXIMUM TEMPERATURES A BIT IN MANY AREAS AS A RESULT.
MODELS HAVE A WEAK LOW TRAVELING NORTHEAST ALONG THIS BOUNDARY
LATE TODAY AND TONIGHT WITH HEAVIEST QPF FOR MID COAST REGION.
WHILE AREAS NEAR ROCKLAND MAY STAY ON THE WARM SIDE OF THE
BOUNDARY AND SEE MAINLY RAIN...IMMEDIATELY ON THE OTHER SIDE OF
THE BOUNDARY SEVERAL INCHES OF WET SNOW WILL FALL. I MADE
ADJUSTMENTS TO 1ST PERIOD GRIDS BASED ON THE MESONET AND TO
REFLECT THE LATEST RADAR TRENDS FOR BANDED PRECIPITATION. ON THE
WATERS...WINDS AND SEAS TOUCHED MARGINAL SMALL CRAFT ALONG THE
BOUNDARY AND I`VE ISSUED AN SCA FOR AREA OUTSIDE THE BAY FOR THE
NEXT FEW HOURS. HRR WINDS WERE USED TO TAILOR WIND GRIDS TO BETTER
REFLECT THE COASTAL BOUNDARY.
PREV DISC...
640 AM...FORECAST THINKING GENERALLY ON TRACK. ACTUALLY MODELS
SEEM TO HAVE A DECENT HANDLE ON THE CURRENT EVENTS...WITH 06Z
NAM12 HANDLING THE LARGER SCALE WELL...CAPTURING THE SHRA DEVELOPING
OVER CT AND LONG ISLAND SOUND...AND THE RUC PICKING UP ON THE VERY
LIGHT SHSN /MAYBE SNIZZLE?/...OVER THE COASTAL PLAIN....WHERE THIS
SHOULD REMAIN SPOTTY THRU THE MORNING...AND CHANGE TO RA ON THE
COAST....BEFORE STEADIER PRECIP DEVELOPS THIS AFTERNOON. ANY CHANGES
TO THE FORECAST BASED ON CURRENT OBS HAVE BEEN MINOR AND ONLY RUN
THRU APPROX THE FIRST 6 HOURS OF THE FORECAST.
PREVIOUSLY...A SOMEWHAT TRICKY FORECAST TODAY INTO TONIGHT AS
VERY WEAK IMPULSES ALOFT...ONE TO OUR S AND ONE TO OUR N PASS
THROUGH WITHIN LESS THAN 12 HOURS OF EACH OTHER...ALTHOUGH EITHER
ONE IS VERY DYNAMIC. THE FIST ONE...IN THE SRN STREAM ACTUALLY
MOVES THROUGH IN THE NEXT FEW HOURS...WITH VERY WEAK SFC
REFLECTION...AND LIGHT PRECIP ASSOCIATED WITH WEAK WAA AHEAD OF IT
MOVED THRU OVERNIGHT. THE SECOND APPROACHES TODAY...AND GENERATES A
BIT MORE LOW TO MID-LVL WAA...WHICH WORKS WITH COASTAL FRONT...AND
GENERATES AN INVERTED SFC TROUGH. THIS PRODUCES SOME MORE ORGANIZED
FORCING ALONG AND JUST INLAND FROM THE COAST THIS AFTERNOON. WHILE
SOME LIGHT PRECIP IS POSSIBLE THIS MORNING...THE BETTER CHC WILL BE
THIS AFTERNOON INTO THE EVENING AS THE FORCING INCREASES. THIS
PRECIP WILL NOT MOVE IN FROM THE WEST SO MUCH AS IT DEVELOPS ALONG
THE COASTAL FRONT.
COASTAL AREAS...FIRST TIER OF COASTAL ZONES...ARE LIKELY TO START
AS RAIN OR SHIFT TO RAIN QUICKLY...BUT P-TYPE WILL BE SOMEWHAT OF
AN ISSUE FOR INLAND AREAS OF THE COASTAL PLAIN. THE COASTAL FRONT
WILL MOVE INLAND TODAY...SO SOME AREAS THAT SEE SOME LIGHT SNOW
EARLY WILL CHANGE TO RAIN THIS AFTERNOON...AND MOST PLACES IN NH
AND FAR WRN ME WILL BE LIMITED TO ABOUT A TENTH OF TOTAL QPF
ANYWAY...WHICH WILL LIMIT TO SNOWFALL TO AN INCH OR SO...MAYBE A
LITTLE MORE IN THE MTNS...WHERE RATIOS WILL BE HIGHER.
MODELS SEEM TO BE FAIR AGREEMENT WHERE HIGHEST QPF WILL
OCCUR...MAINLY E OF KPWM-KLEW...WHERE QPF TODAY INTO THIS EVE
LOOKS BE 0.3-0.4 INCHES. SO INLAND AREAS OF THE KENNEBEC AND
PENOBSCOT VLYS ARE WHERE THE MOST SNOW IS EXPECTED TO FALL. HERE
WE ARE LOOKING AT GENERALLY ONE TO THREE INCHES...WITH SOME 4 INCH
AMOUNTS POSSIBLE. THE BULLSEYE FOR THE HIGHEST SNOWFALL LOOKS TO
BE IN THE SKOWHEGAN-WATERVILLE-UNITY VICINITY.
HOWEVER...MODELS ARE FAR FROM PERFECT WHEN IT COMES TO INVERTED
TROUGHS...AND THIS COULD END UP SHIFTING A BIT.
&&
.SHORT TERM /5 PM THIS AFTERNOON THROUGH 6 PM MONDAY/...
AS THE WEAK
500MB TROUGH ACTUALLY DEEPENS SLIGHTLY JUST TO OUR E LATE
TONIGHT...EXPECTING SOME WEAK RIDGING ALOFT TO DEVELOP BEHIND IT FOR
MONDAY. WILL LOSE A FEW DEGREES AS WINDS SHIFT N ON THE BACK END OF
THE TROUGH...ESPECIALLY IN THE N...AND THIS COULD TURN BACK TO LIGHT
SN BEFORE IT ENDS IN ERN ZONES. SO PRECIP IS EXPECTED TO WIND DOWN
LATE TONIGHT...WITH A BREAK EXPECTED ON MONDAY...ALTHOUGH WE
PROBABLY WILL NOT SEE MUCH SUN ON MONDAY...AS STAGNANT LOW LVL FLOW
LINGERS. HIGHS SHOULD CLIMB BACK INTO THE MID 30S TO AROUND 40 AGAIN.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AS WAS THE CASE THE LAST COUPLE OF NIGHTS...NWP CONTINUES TO
INDICATE SRN STREAM S/WV TROF WILL OUTPACE ITS NRN STREAM
COUNTERPART. THE RESULT IS LOW PRES DEVELOPING OFF THE SOUTHEAST
COASTLINE...AND HEADING OUT TO SEA WITH A LATE CAPTURE THAT SWINGS
IT TOWARDS THE CANADIAN MARITIMES.
CONSENSUS IS THAT PCPN WILL ONLY BRUSH THE COAST...WITH THE
MIDCOAST PERHAPS SEEING A LITTLE LONGER DURATION AS LOW PRES CUTS
ACROSS BAROCLINIC ZONE. MODEL GUIDANCE HAS A VERY SHARP NRN EDGE
TO THE SATURATED SNOW GROWTH ZONE...SO WE WILL BE TREADING A VERY
FINE LINE OF SN OR NO SN HEADING INTO TUE. IN FACT...SFC TEMPS
WILL BE MARGINAL ENOUGH THAT SOME RNFL IS POSSIBLE NEAR THE COAST.
AS UPPER TROF CROSSES THE AREA THERE SHOULD BE ENOUGH FORCING AND
RESIDUAL MOISTURE TO BRING SCT SHSN TO MUCH OF THE AREA BEFORE
HIGH PRES BUILDS IN AND ENDS PCPN. THAT RIDGING WILL BE SHORT
LIVED THOUGH...AS NEXT LOW PRES DEVELOPS AND LIFTS INTO CANADA.
THIS WILL DRIVE A COLD FNT TOWARDS NEW ENGLAND. AFTER INITIAL
BURST OF WAA AHEAD OF THE LOW PRES...COLD WILL SLOWLY OOZE INTO
THE AREA AS FNT BECOMES ALIGNED WITH FLOW ALOFT. AS LONG AS
BOUNDARY REMAINS IN THE AREA IT WILL BE HARD TO RULE OUT
OVERRUNNING PCPN IN BROAD SWLY WAA REGIME.
LATE IN THE WEEK STRONG HIGH PRES WILL BUILD INTO THE
REGION...BEFORE WRN TROF EJECTS NEWD. GIVEN LOCATION OF HIGH
PRES...IT WOULD NOT BE SURPRISING TO SEE NWP TREND COOLER WITH
TIME...THOUGH THERE ARE SEVERAL DAYS BEFORE ANY DETAILS WILL
BECOME MORE CLEAR.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
SHORT TERM...SHOULD SEE ALL TERMINALS GET A PERIOD OF MVFR TO IFR
TODAY WITH SHSN INLAND...AND SHRA ON THE COAST. A STEADIER RA IS
EXPECTED AT KRKD...AND A STEADY MIX OF RASN AT KAUG. CONDITIONS
WILL IMPROVE LATE TONIGHT TO VFR FROM KPWM WWD...AND EVENTUALLY AT
KAUG/KRKD ON MONDAY.
LONG TERM...AREAS OF MVFR OR LOWER CONDITIONS WILL BE POSSIBLE TUE
INTO WED AS OCEAN LOW PRES PASS OUT TO SEA. COASTAL TERMINALS WILL
SEE LOWER CIGS AS WELL AS POSSIBLE SHSN LIMITING VSBYS. PASSAGE OF
UPPER TROF MAY ALSO RESULT IN SOME MTNS SHWRS INVOF OF KHIE.
&&
.MARINE...
SHORT TERM...SOUTHERLY SURGE IN WINDS OCCURRING ATTM AND COULD SEE
A FEW GUSTS UP TO 25 KT THRU SUNRISE. OTHERWISE...QUIET WEATHER
WITH VSBY RESTRICTIONS EXPECTED LATER TONIGHT THROUGH SUNDAY NIGHT
IN DEVELOPING RAIN AND SNOW.
LONG TERM...STILL SOME UNCERTAINTY REGARDING THE TRACK OF COASTAL
LOW PRES MIDWEEK. HOWEVER CONFIDENCE IS GROWING THAT SEAS WILL
BUILD TO AT OR ABOVE 5 FT FOR TUE AND WED. WINDS MORE THAN LIKELY
SHOULD REMAIN AT OR BELOW 25 KTS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR ANZ150-
152-154.
&&
$$
ES
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1147 AM EST SUN DEC 1 2013
.SYNOPSIS...
LOW PRESSURE IS EXPECTED TO CROSS THE STATE TODAY AND REDEVELOP IN
THE GULF OF MAINE TONIGHT, PASSING WELL E OF THE REGION ON MONDAY.
ANOTHER LOW MAY AFFECT THE REGION FROM THE SOUTH TOWARD THE
MIDDLE PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1145 AM UPDATE...A SMALL BAND OF MODERATE SNOW HAS DEVELOPED
ACROSS PORTIONS OF NE AROOSTOOK COUNTY, STRETCHING FROM CARIBOU TO
PORTAGE. LOCATIONS UNDER THIS BAND HAVE PICKED UP A QUARTER TO A
HALF AN INCH OF NEW SNOW. ANOTHER LARGER AREA OF STEADY SNOW CAN
BE SEEN STRETCHING FROM BETWEEN HOULTON AND DANFORTH BACK TOWARD
LINCOLN AND DOVER-FOXCROFT. BOTH OF THESE BANDS OF SNOW WILL
SLOWLY SINK SOUTHWARD THROUGH THE REMAINDER OF THE AFTERNOON. HAVE
UPDATED POPS AND SNOW ACCUMULATIONS TO MATCH THESE TRENDS. ALSO
TWEAKED TEMPERATURES A BIT DOWNEAST AS THERE IS A VERY TIGHT
GRADIENT BETWEEN THE IMMEDIATE COAST (TEMPS IN UPPER 30S) AND
INTERIOR AREAS (BANGOR, WESLEY, AND CHERRYFIELD STILL IN THE LOWER
30S). WITH THIS GRADIENT TO HOLD FAIRLY STEADY, SOME OF THE
INTERIOR DOWNEAST COULD SEE SNOW HOLD ON LONGER WITH LITTLE TO NO
RAIN, MEANING SNOW AMOUNTS WILL BE A BIT HIGHER. SNOW
ACCUMULATIONS WERE ADJUSTED AS NEEDED FOR THIS, AS WELL. NO OTHER
CHANGES WERE NEEDED.
PREVIOUS DISCUSSION...WEAK LOW PRES MOVING ACROSS THE EASTERN
GREAT LAKES IS FCST TO MOVE ACROSS SOUTHERN NEW ENGLAND THIS
AFTERNOON AND THEN INTO THE GULF OF MAINE. THE CONCERN IS WHERE
TO DRAW THE RAIN/SNOW LINE AS WAA MAKES ITS WAY TO THE BLYR.
TEMPERATURES ARE FCST TO REACH INTO THE UPPER 20S TO AROUND 30
ACROSS THE NORTHERN 1/2 OF THE CWA WHILE LOW TO MID 30S ARE
EXPECTED FOR CENTRAL AND DOWNEAST AREAS. AN INVERTED TROF
EXTENDING FROM THE LOW COMBINED W/SOME FRONTOGENETICAL FORCING AT
1000-700MB WILL LEAD TO A REFORMATION OF PRECIP AND AN ENHANCEMENT
OF THE PRECIP. USING THE BUFKIT PROFILES AND SOUNDINGS, THINKING
HERE IS THAT SNOW WILL REDEVELOP ACROSS PORTION OF NORTHEAST MAINE
W/THE HEAVIEST AXIS ACROSS THE HOULTON AND DANFORTH REGION W/LESS
SNOW NORTH AND WEST. S OF OF THE HOULTON-DANFORTH LINE,
TEMPERATURES WILL WARM INTO THE MID 30S TO ALLOW FOR SNOW TO MIX
WITH AND CHANGEOVER TO RAIN. THIS IN TURN WILL CUT DOWN ON
SNOWFALL LATER THIS AFTERNOON INTO TONIGHT. DECISION WAS TO GO
AHEAD AND ADD NORTHERN PENOBSCOT AND SE AROOSTOOK COUNTY IN THE
WINTER WEATHER ADVISORY THROUGH MONDAY MORNING DUE TO ENHANCED
FRONTOGENTICAL FORCING LEADING TO HEAVY SNOW BURSTS. LATEST SNOW
TOTAL MAP SHOWS A GENERAL 4-8 INCHES IN THE ADVISORY AREA W/1-4
INCHES N AND W. THE COAST AND EXTREME EASTERN WASHINGTON COUNTY
FROM MEDDYBEMPS TO EASTPORT WILL SEE 0.30 TO 0.70 INCHES OF
RAINFALL AFTER SOME INITIAL SNOWFALL.
SNOW WILL CONTINUE INTO TONIGHT ACROSS THE NORTHEASTERN SECTION OF
MAINE INCLUDING CARIBOU-PRESQUE ISLE DOWN THROUGH DANFORTH. WEST
OF THIS AREA, LITTLE OR NO SNOW AND RAIN/SNOW S OF THIS AREA
W/RAIN FOR THE COAST AS THE WARM AIR IS FCST TO STAY IN. TEMPERATURES
WILL DROP BACK INTO THE UPPER TEENS AND LOWER 20S NORTH AND WEST
AND MID TO UPPER 20S FOR CENTRAL AREAS. LOW 30S FOR THE DOWNEAST
REGION INCLUDING THE COAST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
SNOW WILL CONTINUE TO WIND DOWN EARLY MONDAY AS THE INVERTED TROF
EXTENDING FROM THE CANADIAN MARITIMES THROUGH DOWNEAST MAINE MOVES
OFF TO THE NORTHEAST. THERE MAY STILL BE SOME LINGERING LIGHT SNOW
OR SNOW SHOWERS PARTICULARLY ACROSS EASTERN AREAS OTHERWISE EXPECT
MOSTLY CLOUDY SKIES ACROSS THE REGION. MONDAY NIGHT WILL BE MOSTLY
CLOUDY BUT DRY AS WEAK HIGH PRESSURE RIDGES DOWN FROM THE NORTH.
ATTENTION THEN TURNS TO ANOTHER LOW PRESSURE SYSTEM THAT WILL BE
MOVING NORTHEAST ACROSS THE WESTERN ATLANTIC. THIS SYSTEM MAY BRINGS
SOME PRECIPITATION TO THE REGION LATER TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MODELS SEEM TO BE COMING INTO BETTER AGREEMENT FOR THE NEXT SYSTEM
TUESDAY NIGHT AND WEDNESDAY. STILL SOME MODEL DIFFERENCES BUT THE
CONSENSUS SOLUTION IS FOR THE LOW TO TRACK FAR ENOUGH EAST THAT ANY
IMPACTS IN OUR REGION WOULD BE ACROSS DOWNEAST/EASTERN MAINE.
A WEAK BOUNDARY WILL CROSS THE REGION BY LATE WEEK WITH SOME
SNOW/RAIN SHOWERS POSSIBLE. AGAIN...WILL STICK CLOSE TO THE
SUPERBLEND.
HIGH PRESSURE WILL BUILD EAST TOWARD THE REGION BY SATURDAY.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: MVFR W/PERIODS OF VFR THIS MORNING DROPPING TO MVFR AND
EVEN IFR LATER THIS MORNING ON INTO TONIGHT. SNOW ACROSS THE NORTHERN
TERMINALS W/SNOW TO RAIN FOR KBGR TO KBHB.
SHORT TERM: MVFR CONDS ARE POSSIBLE EARLY MONDAY THEN VFR CONDS
EXPECTED MONDAY NIGHT INTO TUESDAY. MVFR CONDS ARE POSSIBLE IN
SOME LIGHT PRECIP LATE TUESDAY AND INTO EARLY WEDNESDAY. VFR ON
THURSDAY.
&&
.MARINE...
NEAR TERM: THE SMALL CRAFT ADVISORY HAS BEEN EXTENDED THROUGH 4 PM
THIS AFTERNOON FOR THE OUTER WATERS AS BUOYS ARE STILL REPORTING
WINDS GUSTING 20-25 KT AND WAVES 5-6 FT. CONDITIONS IN THE INNER
WATERS HAVE IMPROVED, SO THE SCA WAS ALLOWED TO EXPIRE THERE.
PREVIOUS DISCUSSION...DECIDED TO GO W/A SCA THROUGH LATE MORNING. WINDS
GUSTING TO 25 KTS AS LLVL JET OF 30 KT MOVES ACROSS THE WATERS.
THE GFS AND NAM AS WELL AS THE LATEST RAP MODEL PICK UP ON THIS
FEATURE. WINDS ARE FCST TO DROP OFF THIS AFTERNOON AS THE LLVL JET
SHIFTS TO THE E. SEAS ARE AT 5FT AND COULD TIP 6 FT ESPECIALLY AT
44027(JONESPORT) THIS MORNING. SEAS WILL GRADUALLY SUBSIDE TONIGHT
BELOW 4 FT.
SHORT TERM: WINDS/SEAS WILL BE BELOW SCA LEVELS MON AND MON NIGHT.
WIND/SEAS MAY INCREASE TO SCA LEVELS TUE/TUE NIGHT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR MEZ005-006-
011-016-017-032.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ050-
051.
&&
$$
NEAR TERM...HASTINGS/HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HASTINGS/HEWITT/DUDA
MARINE...HASTINGS/HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS GRAY ME
956 AM EST SUN DEC 1 2013
.SYNOPSIS...
WEAK LOW PRESSURE AND AN ASSOCIATED COLD FRONT WILL SLIDE SOUTHEAST
ACROSS THE AREA THROUGH TONIGHT. A SECOND WEAK LOW WILL TRACK
NORTHEAST AND PASS JUST OFFSHORE TONIGHT AND EARLY MONDAY. THESE
TWO SYSTEMS WILL PRODUCE SOME OCCASIONAL LIGHT SNOW INTO TONIGHT,
WITH MIXING OR A CHANGEOVER TO LIGHT RAIN POSSIBLE NEAR THE COAST.
WEAK TROUGHING ALONG THE COAST KEEPS PRECIPITATION NEARBY ON
MONDAY. LOW PRESSURE TRAVELS UP THE ATLANTIC COASTLINE TUESDAY,
SPREADING MORE PRECIPITATION OVER THE REGION THROUGH WEDNESDAY
MORNING. RIDGING BUILDS IN BRIEFLY BEFORE A COLD FRONT CROSSES THE
REGION THURSDAY.
&&
.NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
945 AM...THE COASTAL FRONT IS SETTING UP SHOP JUST OFFSHORE THEN
EXTENDS INTO MY EASTERN ZONES AND TO THE WEST OF ROCKLAND. I LOWERED
MAXIMUM TEMPERATURES A BIT IN MANY AREAS AS A RESULT. MODELS HAVE A
WEAK LOW TRAVELING NORTHEAST ALONG THIS BOUNDARY LATE TODAY AND
TONIGHT WITH HEAVIEST QPF FOR MID COAST REGION. WHILE AREAS NEAR
ROCKLAND MAY STAY ON THE WARM SIDE OF THE BOUNDARY AND SEE MAINLY
RAIN...IMMEDIATELY ON THE OTHER SIDE OF THE BOUNDARY SEVERAL
INCHES OF WET SNOW WILL FALL. I MADE ADJUSTMENTS TO 1ST PERIOD
GRIDS BASED ON THE MESONET AND TO REFLECT THE LATEST RADAR TRENDS
FOR BANDED PRECIPITATION. ON THE WATERS...WINDS AND SEAS TOUCHED
MARGINAL SMALL CRAFT ALONG THE BOUNDARY AND I`VE ISSUED AN SCA FOR
AREA OUTSIDE THE BAY FOR THE NEXT FEW HOURS. HRR WINDS WERE USED
TO TAILOR WIND GRIDS TO BETTER REFLECT THE COASTAL BOUNDARY.
PREV DISC...
640 AM...FORECAST THINKING GENERALLY ON TRACK. ACTUALLY MODELS
SEEM TO HAVE A DECENT HANDLE ON THE CURRENT EVENTS...WITH 06Z
NAM12 HANDLING THE LARGER SCALE WELL...CAPTURING THE SHRA DEVELOPING
OVER CT AND LONG ISLAND SOUND...AND THE RUC PICKING UP ON THE VERY
LIGHT SHSN /MAYBE SNIZZLE?/...OVER THE COASTAL PLAIN....WHERE THIS
SHOULD REMAIN SPOTTY THRU THE MORNING...AND CHANGE TO RA ON THE
COAST....BEFORE STEADIER PRECIP DEVELOPS THIS AFTERNOON. ANY CHANGES
TO THE FORECAST BASED ON CURRENT OBS HAVE BEEN MINOR AND ONLY RUN
THRU APPROX THE FIRST 6 HOURS OF THE FORECAST.
PREVIOUSLY...A SOMEWHAT TRICKY FORECAST TODAY INTO TONIGHT AS
VERY WEAK IMPULSES ALOFT...ONE TO OUR S AND ONE TO OUR N PASS
THROUGH WITHIN LESS THAN 12 HOURS OF EACH OTHER...ALTHOUGH EITHER
ONE IS VERY DYNAMIC. THE FIST ONE...IN THE SRN STREAM ACTUALLY
MOVES THROUGH IN THE NEXT FEW HOURS...WITH VERY WEAK SFC
REFLECTION...AND LIGHT PRECIP ASSOCIATED WITH WEAK WAA AHEAD OF IT
MOVED THRU OVERNIGHT. THE SECOND APPROACHES TODAY...AND GENERATES A
BIT MORE LOW TO MID-LVL WAA...WHICH WORKS WITH COASTAL FRONT...AND
GENERATES AN INVERTED SFC TROUGH. THIS PRODUCES SOME MORE ORGANIZED
FORCING ALONG AND JUST INLAND FROM THE COAST THIS AFTERNOON. WHILE
SOME LIGHT PRECIP IS POSSIBLE THIS MORNING...THE BETTER CHC WILL BE
THIS AFTERNOON INTO THE EVENING AS THE FORCING INCREASES. THIS
PRECIP WILL NOT MOVE IN FROM THE WEST SO MUCH AS IT DEVELOPS ALONG
THE COASTAL FRONT.
COASTAL AREAS...FIRST TIER OF COASTAL ZONES...ARE LIKELY TO START
AS RAIN OR SHIFT TO RAIN QUICKLY...BUT P-TYPE WILL BE SOMEWHAT OF
AN ISSUE FOR INLAND AREAS OF THE COASTAL PLAIN. THE COASTAL FRONT
WILL MOVE INLAND TODAY...SO SOME AREAS THAT SEE SOME LIGHT SNOW
EARLY WILL CHANGE TO RAIN THIS AFTERNOON...AND MOST PLACES IN NH
AND FAR WRN ME WILL BE LIMITED TO ABOUT A TENTH OF TOTAL QPF
ANYWAY...WHICH WILL LIMIT TO SNOWFALL TO AN INCH OR SO...MAYBE A
LITTLE MORE IN THE MTNS...WHERE RATIOS WILL BE HIGHER.
MODELS SEEM TO BE FAIR AGREEMENT WHERE HIGHEST QPF WILL
OCCUR...MAINLY E OF KPWM-KLEW...WHERE QPF TODAY INTO THIS EVE
LOOKS BE 0.3-0.4 INCHES. SO INLAND AREAS OF THE KENNEBEC AND
PENOBSCOT VLYS ARE WHERE THE MOST SNOW IS EXPECTED TO FALL. HERE
WE ARE LOOKING AT GENERALLY ONE TO THREE INCHES...WITH SOME 4 INCH
AMOUNTS POSSIBLE. THE BULLSEYE FOR THE HIGHEST SNOWFALL LOOKS TO
BE IN THE SKOWHEGAN-WATERVILLE-UNITY VICINITY.
HOWEVER...MODELS ARE FAR FROM PERFECT WHEN IT COMES TO INVERTED
TROUGHS...AND THIS COULD END UP SHIFTING A BIT.
&&
.SHORT TERM /5 PM THIS AFTERNOON THROUGH 6 PM MONDAY/...
AS THE WEAK
500MB TROUGH ACTUALLY DEEPENS SLIGHTLY JUST TO OUR E LATE
TONIGHT...EXPECTING SOME WEAK RIDGING ALOFT TO DEVELOP BEHIND IT FOR
MONDAY. WILL LOSE A FEW DEGREES AS WINDS SHIFT N ON THE BACK END OF
THE TROUGH...ESPECIALLY IN THE N...AND THIS COULD TURN BACK TO LIGHT
SN BEFORE IT ENDS IN ERN ZONES. SO PRECIP IS EXPECTED TO WIND DOWN
LATE TONIGHT...WITH A BREAK EXPECTED ON MONDAY...ALTHOUGH WE
PROBABLY WILL NOT SEE MUCH SUN ON MONDAY...AS STAGNANT LOW LVL FLOW
LINGERS. HIGHS SHOULD CLIMB BACK INTO THE MID 30S TO AROUND 40 AGAIN.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AS WAS THE CASE THE LAST COUPLE OF NIGHTS...NWP CONTINUES TO
INDICATE SRN STREAM S/WV TROF WILL OUTPACE ITS NRN STREAM
COUNTERPART. THE RESULT IS LOW PRES DEVELOPING OFF THE SOUTHEAST
COASTLINE...AND HEADING OUT TO SEA WITH A LATE CAPTURE THAT SWINGS
IT TOWARDS THE CANADIAN MARITIMES.
CONSENSUS IS THAT PCPN WILL ONLY BRUSH THE COAST...WITH THE
MIDCOAST PERHAPS SEEING A LITTLE LONGER DURATION AS LOW PRES CUTS
ACROSS BAROCLINIC ZONE. MODEL GUIDANCE HAS A VERY SHARP NRN EDGE
TO THE SATURATED SNOW GROWTH ZONE...SO WE WILL BE TREADING A VERY
FINE LINE OF SN OR NO SN HEADING INTO TUE. IN FACT...SFC TEMPS
WILL BE MARGINAL ENOUGH THAT SOME RNFL IS POSSIBLE NEAR THE COAST.
AS UPPER TROF CROSSES THE AREA THERE SHOULD BE ENOUGH FORCING AND
RESIDUAL MOISTURE TO BRING SCT SHSN TO MUCH OF THE AREA BEFORE
HIGH PRES BUILDS IN AND ENDS PCPN. THAT RIDGING WILL BE SHORT
LIVED THOUGH...AS NEXT LOW PRES DEVELOPS AND LIFTS INTO CANADA.
THIS WILL DRIVE A COLD FNT TOWARDS NEW ENGLAND. AFTER INITIAL
BURST OF WAA AHEAD OF THE LOW PRES...COLD WILL SLOWLY OOZE INTO
THE AREA AS FNT BECOMES ALIGNED WITH FLOW ALOFT. AS LONG AS
BOUNDARY REMAINS IN THE AREA IT WILL BE HARD TO RULE OUT
OVERRUNNING PCPN IN BROAD SWLY WAA REGIME.
LATE IN THE WEEK STRONG HIGH PRES WILL BUILD INTO THE
REGION...BEFORE WRN TROF EJECTS NEWD. GIVEN LOCATION OF HIGH
PRES...IT WOULD NOT BE SURPRISING TO SEE NWP TREND COOLER WITH
TIME...THOUGH THERE ARE SEVERAL DAYS BEFORE ANY DETAILS WILL
BECOME MORE CLEAR.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...SHOULD SEE ALL TERMINALS GET A PERIOD OF MVFR TO IFR
TODAY WITH SHSN INLAND...AND SHRA ON THE COAST. A STEADIER RA IS
EXPECTED AT KRKD...AND A STEADY MIX OF RASN AT KAUG. CONDITIONS
WILL IMPROVE LATE TONIGHT TO VFR FROM KPWM WWD...AND EVENTUALLY AT
KAUG/KRKD ON MONDAY.
LONG TERM...AREAS OF MVFR OR LOWER CONDITIONS WILL BE POSSIBLE TUE
INTO WED AS OCEAN LOW PRES PASS OUT TO SEA. COASTAL TERMINALS WILL
SEE LOWER CIGS AS WELL AS POSSIBLE SHSN LIMITING VSBYS. PASSAGE OF
UPPER TROF MAY ALSO RESULT IN SOME MTNS SHWRS INVOF OF KHIE.
&&
.MARINE...
SHORT TERM...SOUTHERLY SURGE IN WINDS OCCURRING ATTM AND COULD SEE
A FEW GUSTS UP TO 25 KT THRU SUNRISE. OTHERWISE...QUIET WEATHER
WITH VSBY RESTRICTIONS EXPECTED LATER TONIGHT THROUGH SUNDAY NIGHT
IN DEVELOPING RAIN AND SNOW.
LONG TERM...STILL SOME UNCERTAINTY REGARDING THE TRACK OF COASTAL
LOW PRES MIDWEEK. HOWEVER CONFIDENCE IS GROWING THAT SEAS WILL
BUILD TO AT OR ABOVE 5 FT FOR TUE AND WED. WINDS MORE THAN LIKELY
SHOULD REMAIN AT OR BELOW 25 KTS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR ANZ150-
152-154.
&&
$$
SCHWIBS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
915 AM EST SUN DEC 1 2013
.SYNOPSIS...
LOW PRESSURE IS EXPECTED TO CROSS THE STATE TODAY AND REDEVELOP IN
THE GULF OF MAINE TONIGHT, PASSING WELL E OF THE REGION ON MONDAY.
ANOTHER LOW MAY AFFECT THE REGION FROM THE SOUTH TOWARD THE
MIDDLE PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
915 AM UPDATE...NO SIGNIFICANT CHANGES WERE NEEDED WITH THIS
UPDATE. MADE SOME SLIGHT ADJUSTMENTS TO POPS THROUGH THIS
AFTERNOON TO MATCH CURRENT RADAR TRENDS AND THE LATEST GUIDANCE.
ALSO BUMPED UP TEMPS JUST A BIT ALONG THE COAST, WHERE IT`S
ALREADY IN THE MID 30S. OTHERWISE, NO OTHER CHANGES WERE NEEDED.
PREVIOUS DISCUSSION...WEAK LOW PRES MOVING ACROSS THE EASTERN
GREAT LAKES IS FCST TO MOVE ACROSS SOUTHERN NEW ENGLAND THIS
AFTERNOON AND THEN INTO THE GULF OF MAINE. THE CONCERN IS WHERE
TO DRAW THE RAIN/SNOW LINE AS WAA MAKES ITS WAY TO THE BLYR.
TEMPERATURES ARE FCST TO REACH INTO THE UPPER 20S TO AROUND 30
ACROSS THE NORTHERN 1/2 OF THE CWA WHILE LOW TO MID 30S ARE
EXPECTED FOR CENTRAL AND DOWNEAST AREAS. AN INVERTED TROF
EXTENDING FROM THE LOW COMBINED W/SOME FRONTOGENETICAL FORCING AT
1000-700MB WILL LEAD TO A REFORMATION OF PRECIP AND AN ENHANCEMENT
OF THE PRECIP. USING THE BUFKIT PROFILES AND SOUNDINGS, THINKING
HERE IS THAT SNOW WILL REDEVELOP ACROSS PORTION OF NORTHEAST MAINE
W/THE HEAVIEST AXIS ACROSS THE HOULTON AND DANFORTH REGION W/LESS
SNOW NORTH AND WEST. S OF OF THE HOULTON-DANFORTH LINE,
TEMPERATURES WILL WARM INTO THE MID 30S TO ALLOW FOR SNOW TO MIX
WITH AND CHANGEOVER TO RAIN. THIS IN TURN WILL CUT DOWN ON
SNOWFALL LATER THIS AFTERNOON INTO TONIGHT. DECISION WAS TO GO
AHEAD AND ADD NORTHERN PENOBSCOT AND SE AROOSTOOK COUNTY IN THE
WINTER WEATHER ADVISORY THROUGH MONDAY MORNING DUE TO ENHANCED
FRONTOGENTICAL FORCING LEADING TO HEAVY SNOW BURSTS. LATEST SNOW
TOTAL MAP SHOWS A GENERAL 4-8 INCHES IN THE ADVISORY AREA W/1-4
INCHES N AND W. THE COAST AND EXTREME EASTERN WASHINGTON COUNTY
FROM MEDDYBEMPS TO EASTPORT WILL SEE 0.30 TO 0.70 INCHES OF
RAINFALL AFTER SOME INITIAL SNOWFALL.
SNOW WILL CONTINUE INTO TONIGHT ACROSS THE NORTHEASTERN SECTION OF
MAINE INCLUDING CARIBOU-PRESQUE ISLE DOWN THROUGH DANFORTH. WEST
OF THIS AREA, LITTLE OR NO SNOW AND RAIN/SNOW S OF THIS AREA
W/RAIN FOR THE COAST AS THE WARM AIR IS FCST TO STAY IN. TEMPERATURES
WILL DROP BACK INTO THE UPPER TEENS AND LOWER 20S NORTH AND WEST
AND MID TO UPPER 20S FOR CENTRAL AREAS. LOW 30S FOR THE DOWNEAST
REGION INCLUDING THE COAST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
SNOW WILL CONTINUE TO WIND DOWN EARLY MONDAY AS THE INVERTED TROF
EXTENDING FROM THE CANADIAN MARITIMES THROUGH DOWNEAST MAINE MOVES
OFF TO THE NORTHEAST. THERE MAY STILL BE SOME LINGERING LIGHT SNOW
OR SNOW SHOWERS PARTICULARLY ACROSS EASTERN AREAS OTHERWISE EXPECT
MOSTLY CLOUDY SKIES ACROSS THE REGION. MONDAY NIGHT WILL BE MOSTLY
CLOUDY BUT DRY AS WEAK HIGH PRESSURE RIDGES DOWN FROM THE NORTH.
ATTENTION THEN TURNS TO ANOTHER LOW PRESSURE SYSTEM THAT WILL BE
MOVING NORTHEAST ACROSS THE WESTERN ATLANTIC. THIS SYSTEM MAY BRINGS
SOME PRECIPITATION TO THE REGION LATER TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MODELS SEEM TO BE COMING INTO BETTER AGREEMENT FOR THE NEXT SYSTEM
TUESDAY NIGHT AND WEDNESDAY. STILL SOME MODEL DIFFERENCES BUT THE
CONSENSUS SOLUTION IS FOR THE LOW TO TRACK FAR ENOUGH EAST THAT ANY
IMPACTS IN OUR REGION WOULD BE ACROSS DOWNEAST/EASTERN MAINE.
A WEAK BOUNDARY WILL CROSS THE REGION BY LATE WEEK WITH SOME
SNOW/RAIN SHOWERS POSSIBLE. AGAIN...WILL STICK CLOSE TO THE
SUPERBLEND.
HIGH PRESSURE WILL BUILD EAST TOWARD THE REGION BY SATURDAY.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: MVFR W/PERIODS OF VFR THIS MORNING DROPPING TO MVFR AND
EVEN IFR LATER THIS MORNING ON INTO TONIGHT. SNOW ACROSS THE NORTHERN
TERMINALS W/SNOW TO RAIN FOR KBGR TO KBHB.
SHORT TERM: MVFR CONDS ARE POSSIBLE EARLY MONDAY THEN VFR CONDS
EXPECTED MONDAY NIGHT INTO TUESDAY. MVFR CONDS ARE POSSIBLE IN
SOME LIGHT PRECIP LATE TUESDAY AND INTO EARLY WEDNESDAY. VFR ON
THURSDAY.
&&
.MARINE...
NEAR TERM: DECIDED TO GO W/A SCA THROUGH LATE MORNING. WINDS
GUSTING TO 25 KTS AS LLVL JET OF 30 KT MOVES ACROSS THE WATERS.
THE GFS AND NAM AS WELL AS THE LATEST RAP MODEL PICK UP ON THIS
FEATURE. WINDS ARE FCST TO DROP OFF THIS AFTERNOON AS THE LLVL JET
SHIFTS TO THE E. SEAS ARE AT 5FT AND COULD TIP 6 FT ESPECIALLY AT
44027(JONESPORT) THIS MORNING. SEAS WILL GRADUALLY SUBSIDE TONIGHT
BELOW 4 FT.
SHORT TERM: WINDS/SEAS WILL BE BELOW SCA LEVELS MON AND MON NIGHT.
WIND/SEAS MAY INCREASE TO SCA LEVELS TUE/TUE NIGHT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR MEZ005-006-
011-016-017-032.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR
ANZ050>052.
&&
$$
NEAR TERM...HASTINGS/HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HASTINGS/HEWITT/DUDA
MARINE...HASTINGS/HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS GRAY ME
817 AM EST SUN DEC 1 2013
.SYNOPSIS...
WEAK LOW PRESSURE WILL TRACK SOUTHEAST OUT OF QUEBEC AND ACROSS
THE AREA TONIGHT...PRODUCING SOME LIGHT SNOW INLAND AND A MIX OF
SNOW AND RAIN NEAR THE COAST. WEAK TROUGHING ALONG THE COAST KEEPS
PRECIPITATION NEARBY ON MONDAY. LOW PRESSURE TRAVELS UP THE
ATLANTIC COASTLINE TUESDAY...SPREADING MORE PRECIPITATION OVER THE
REGION THROUGH WEDNESDAY MORNING. RIDGING BUILDS IN BRIEFLY BEFORE
A COLD FRONT CROSSES THE REGION THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
640 AM...FORECAST THINKING GENERALLY ON TRACK. ACTUALLY MODELS
SEEM TO HAVE A DECENT HANDLE ON THE CURRENT EVENTS...WITH 06Z
NAM12 HANDLING THE LARGER SCALE WELL...CAPTURING THE SHRA DEVELOPING
OVER CT AND LONG ISLAND SOUND...AND THE RUC PICKING UP ON THE VERY
LIGHT SHSN /MAYBE SNIZZLE?/...OVER THE COASTAL PLAIN....WHERE THIS
SHOULD REMAIN SPOTTY THRU THE MORNING...AND CHANGE TO RA ON THE
COAST....BEFORE STEADIER PRECIP DEVELOPS THIS AFTERNOON. ANY CHANGES
TO THE FORECAST BASED ON CURRENT OBS HAVE BEEN MINOR AND ONLY RUN
THRU APPROX THE FIRST 6 HOURS OF THE FORECAST.
PREVIOUSLY...A SOMEWHAT TRICKY FORECAST TODAY INTO TONIGHT AS
VERY WEAK IMPULSES ALOFT...ONE TO OUR S AND ONE TO OUR N PASS
THROUGH WITHIN LESS THAN 12 HOURS OF EACH OTHER...ALTHOUGH EITHER
ONE IS VERY DYNAMIC. THE FIST ONE...IN THE SRN STREAM ACTUALLY
MOVES THROUGH IN THE NEXT FEW HOURS...WITH VERY WEAK SFC
REFLECTION...AND LIGHT PRECIP ASSOCIATED WITH WEAK WAA AHEAD OF IT
MOVED THRU OVERNIGHT. THE SECOND APPROACHES TODAY...AND GENERATES A
BIT MORE LOW TO MID-LVL WAA...WHICH WORKS WITH COASTAL FRONT...AND
GENERATES AN INVERTED SFC TROUGH. THIS PRODUCES SOME MORE ORGANIZED
FORCING ALONG AND JUST INLAND FROM THE COAST THIS AFTERNOON. WHILE
SOME LIGHT PRECIP IS POSSIBLE THIS MORNING...THE BETTER CHC WILL BE
THIS AFTERNOON INTO THE EVENING AS THE FORCING INCREASES. THIS
PRECIP WILL NOT MOVE IN FROM THE WEST SO MUCH AS IT DEVELOPS ALONG
THE COASTAL FRONT.
COASTAL AREAS...FIRST TIER OF COASTAL ZONES...ARE LIKELY TO START
AS RAIN OR SHIFT TO RAIN QUICKLY...BUT P-TYPE WILL BE SOMEWHAT OF
AN ISSUE FOR INLAND AREAS OF THE COASTAL PLAIN. THE COASTAL FRONT
WILL MOVE INLAND TODAY...SO SOME AREAS THAT SEE SOME LIGHT SNOW
EARLY WILL CHANGE TO RAIN THIS AFTERNOON...AND MOST PLACES IN NH
AND FAR WRN ME WILL BE LIMITED TO ABOUT A TENTH OF TOTAL QPF
ANYWAY...WHICH WILL LIMIT TO SNOWFALL TO AN INCH OR SO...MAYBE A
LITTLE MORE IN THE MTNS...WHERE RATIOS WILL BE HIGHER.
MODELS SEEM TO BE FAIR AGREEMENT WHERE HIGHEST QPF WILL
OCCUR...MAINLY E OF KPWM-KLEW...WHERE QPF TODAY INTO THIS EVE
LOOKS BE 0.3-0.4 INCHES. SO INLAND AREAS OF THE KENNEBEC AND
PENOBSCOT VLYS ARE WHERE THE MOST SNOW IS EXPECTED TO FALL. HERE
WE ARE LOOKING AT GENERALLY ONE TO THREE INCHES...WITH SOME 4 INCH
AMOUNTS POSSIBLE. THE BULLSEYE FOR THE HIGHEST SNOWFALL LOOKS TO
BE IN THE SKOWHEGAN-WATERVILLE-UNITY VICINITY.
HOWEVER...MODELS ARE FAR FROM PERFECT WHEN IT COMES TO INVERTED
TROUGHS...AND THIS COULD END UP SHIFTING A BIT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...AS THE WEAK
500MB TROUGH ACTUALLY DEEPENS SLIGHTLY JUST TO OUR E LATE
TONIGHT...EXPECTING SOME WEAK RIDGING ALOFT TO DEVELOP BEHIND IT FOR
MONDAY. WILL LOSE A FEW DEGREES AS WINDS SHIFT N ON THE BACK END OF
THE TROUGH...ESPECIALLY IN THE N...AND THIS COULD TURN BACK TO LIGHT
SN BEFORE IT ENDS IN ERN ZONES. SO PRECIP IS EXPECTED TO WIND DOWN
LATE TONIGHT...WITH A BREAK EXPECTED ON MONDAY...ALTHOUGH WE
PROBABLY WILL NOT SEE MUCH SUN ON MONDAY...AS STAGNANT LOW LVL FLOW
LINGERS. HIGHS SHOULD CLIMB BACK INTO THE MID 30S TO AROUND 40 AGAIN.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AS WAS THE CASE THE LAST COUPLE OF NIGHTS...NWP CONTINUES TO
INDICATE SRN STREAM S/WV TROF WILL OUTPACE ITS NRN STREAM
COUNTERPART. THE RESULT IS LOW PRES DEVELOPING OFF THE SOUTHEAST
COASTLINE...AND HEADING OUT TO SEA WITH A LATE CAPTURE THAT SWINGS
IT TOWARDS THE CANADIAN MARITIMES.
CONSENSUS IS THAT PCPN WILL ONLY BRUSH THE COAST...WITH THE
MIDCOAST PERHAPS SEEING A LITTLE LONGER DURATION AS LOW PRES CUTS
ACROSS BAROCLINIC ZONE. MODEL GUIDANCE HAS A VERY SHARP NRN EDGE
TO THE SATURATED SNOW GROWTH ZONE...SO WE WILL BE TREADING A VERY
FINE LINE OF SN OR NO SN HEADING INTO TUE. IN FACT...SFC TEMPS
WILL BE MARGINAL ENOUGH THAT SOME RNFL IS POSSIBLE NEAR THE COAST.
AS UPPER TROF CROSSES THE AREA THERE SHOULD BE ENOUGH FORCING AND
RESIDUAL MOISTURE TO BRING SCT SHSN TO MUCH OF THE AREA BEFORE
HIGH PRES BUILDS IN AND ENDS PCPN. THAT RIDGING WILL BE SHORT
LIVED THOUGH...AS NEXT LOW PRES DEVELOPS AND LIFTS INTO CANADA.
THIS WILL DRIVE A COLD FNT TOWARDS NEW ENGLAND. AFTER INITIAL
BURST OF WAA AHEAD OF THE LOW PRES...COLD WILL SLOWLY OOZE INTO
THE AREA AS FNT BECOMES ALIGNED WITH FLOW ALOFT. AS LONG AS
BOUNDARY REMAINS IN THE AREA IT WILL BE HARD TO RULE OUT
OVERRUNNING PCPN IN BROAD SWLY WAA REGIME.
LATE IN THE WEEK STRONG HIGH PRES WILL BUILD INTO THE
REGION...BEFORE WRN TROF EJECTS NEWD. GIVEN LOCATION OF HIGH
PRES...IT WOULD NOT BE SURPRISING TO SEE NWP TREND COOLER WITH
TIME...THOUGH THERE ARE SEVERAL DAYS BEFORE ANY DETAILS WILL
BECOME MORE CLEAR.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...SHOULD SEE ALL TERMINALS GET A PERIOD OF MVFR TO IFR
TODAY WITH SHSN INLAND...AND SHRA ON THE COAST. A STEADIER RA IS
EXPECTED AT KRKD...AND A STEADY MIX OF RASN AT KAUG. CONDITIONS
WILL IMPROVE LATE TONIGHT TO VFR FROM KPWM WWD...AND EVENTUALLY AT
KAUG/KRKD ON MONDAY.
LONG TERM...AREAS OF MVFR OR LOWER CONDITIONS WILL BE POSSIBLE TUE
INTO WED AS OCEAN LOW PRES PASS OUT TO SEA. COASTAL TERMINALS WILL
SEE LOWER CIGS AS WELL AS POSSIBLE SHSN LIMITING VSBYS. PASSAGE OF
UPPER TROF MAY ALSO RESULT IN SOME MTNS SHWRS INVOF OF KHIE.
&&
.MARINE...
SHORT TERM...SOUTHERLY SURGE IN WINDS OCCURRING ATTM AND COULD SEE
A FEW GUSTS UP TO 25 KT THRU SUNRISE. OTHERWISE...QUIET WEATHER
WITH VSBY RESTRICTIONS EXPECTED LATER TONIGHT THROUGH SUNDAY NIGHT
IN DEVELOPING RAIN AND SNOW.
LONG TERM...STILL SOME UNCERTAINTY REGARDING THE TRACK OF COASTAL
LOW PRES MIDWEEK. HOWEVER CONFIDENCE IS GROWING THAT SEAS WILL
BUILD TO AT OR ABOVE 5 FT FOR TUE AND WED. WINDS MORE THAN LIKELY
SHOULD REMAIN AT OR BELOW 25 KTS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...CEMPA
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS GRAY ME
644 AM EST SUN DEC 1 2013
.SYNOPSIS...
WEAK LOW PRESSURE WILL TRACK SOUTHEAST OUT OF QUEBEC AND ACROSS
THE AREA TONIGHT...PRODUCING SOME LIGHT SNOW INLAND AND A MIX OF
SNOW AND RAIN NEAR THE COAST. WEAK TROUGHING ALONG THE COAST KEEPS
PRECIPITATION NEARBY ON MONDAY. LOW PRESSURE TRAVELS UP THE
ATLANTIC COASTLINE TUESDAY...SPREADING MORE PRECIPITATION OVER THE
REGION THROUGH WEDNESDAY MORNING. RIDGING BUILDS IN BRIEFLY BEFORE
A COLD FRONT CROSSES THE REGION THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
640 AM...FORECAST THINKING GENERALLY ON TRACK. ACTUALLY MODELS
SEEM TO HAVE A DECENT HANDLE ON THE CURRENT EVENTS...WITH 06Z
NAM12 HANDLING THE LARGER SCALE WELL...CAPTURING THE SHRA
DEVELOPING OVER CT AND LI SOUND...AND THE RUC PICKING UP ON THE
VERY LIGHT SHSN /MAYBE SNIZZLE?/...OVER THE COASTAL PLAIN....WHERE
THIS SHOULD REMAIN SPOTTY THRU THE MORNING...AND CHANGE TO RA ON
THE COAST....BEFORE STEADIER PRECIP DEVELOPS THIS AFTERNOON. ANY
CHANGES TO THE FORECAST BASED ON CURRENT OBS HAVE BEEN MINOR AND
ONLY RUN THRU APPROX THE FIRST 6 HOURS OF THE FORECAST.
PREVIOUSLY...A SOMEWHAT TRICKY FORECAST TODAY INTO TONIGHT AS
VERY WEAK IMPULSES ALOFT...ONE TO OUR S AND ONE TO OUR N PASS
THROUGH WITHIN LESS THAN 12 HOURS OF EACH OTHER...ALTHOUGH EITHER
ONE IS VERY DYNAMIC. THE FIST ONE...IN THE SRN STREAM ACTUALLY
MOVES THROUGH IN THE NEXT FEW HOURS...WITH VERY WEAK SFC
REFLECTION...AND LIGHT PRECIP ASSOCIATED WITH WEAK WAA AHEAD OF IT
MOVED THRU OVERNIGHT. THE SECOND APPROACHES TODAY...AND GENERATES
A BIT MORE LOW TO MID- LVL WAA...WHICH WORKS WITH COASTAL
FRONT...AND GENERATES A AN INVERTED SFC TROUGH. THIS PRODUCES SOME
MORE ORGANIZED FORCING ALONG AND JUST INLAND FROM THE COAST THIS
AFTERNOON. WHILE SOME LIGHT PRECIP IS POSSIBLE THIS MORNING...THE
BETTER CHC WILL BE THIS AFTERNOON INTO THE EVENING AS THE FORCING
INCREASES. THIS PRECIP WILL NOT MOVE IN FROM THE WEST SO MUCH AS
IT DEVELOPS ALONG THE COASTAL FRONT.
COASTAL AREAS...FIRST TIER OF COASTAL ZONES...ARE LIKELY TO START
AS RAIN OR SHIFT TO RAIN QUICKLY...BUT P-TYPE WILL BE SOMEWHAT OF
AN ISSUE FOR INLAND AREAS OF THE COASTAL PLAIN. THE COASTAL FRONT
WILL MOVE INLAND TODAY...SO SOME AREAS THAT SEE SOME LIGHT SNOW
EARLY WILL CHANGE TO RAIN THIS AFTERNOON...AND MOST PLACES IN NH
AND FAR WRN ME WILL BE LIMITED TO ABOUT A TENTH OF TOTAL QPF
ANYWAY...WHICH WILL LIMIT TO SNOWFALL TO AN INCH OR SO...MAYBE A
LITTLE MORE IN THE MTNS...WHERE RATIOS WILL BE HIGHER.
MODELS SEEM TO BE FAIR AGREEMENT WHERE HIGHEST QPF WILL
OCCUR...MAINLY E OF KPWM-KLEW...WHERE QPF TODAY INTO THIS EVE
LOOKS BE 0.3-0.4 INCHES. SO INLAND AREAS OF THE KENNEBEC AND
PENOBSCOT VLYS ARE WHERE THE MOST SNOW IS EXPECTED TO FALL. HERE
WE ARE LOOKING AT GENERALLY ONE TO THREE INCHES...WITH SOME 4 INCH
AMOUNTS POSSIBLE. THE BULLSYEYE FOR THE HIGHEST SNOWFALL LOOKS TO
BE IN THE SKOWHEGAN-WATERVILLE-UNITY VICINITY.
HOWEVER...MODELS ARE FAR FROM PERFECT WHEN IT COMES TO INVERTED
TROUGHS...AND THIS COULD END UP SHIFTING A BIT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
AS THE WEAK 500MB TROUGH ACTUALLY DEEPENS SLIGHTLY JUST TOUR E
LATE TONIGHT...EXPECTING SOME WEAK RIDGING ALOFT TO DEVELOP BEHIND
IT FOR MONDAY. WILL LOSE A FEW DEGREES AS WINDS SHIFT N ON THE
BACK END OF THE TROUGH...ESPECIALLY IN THE N,...AND THIS COULD
TURN BACK TO LIGHT SN BEFORE IT ENDS IN ERN ZONES. SO PRECIP IS
EXPECTED TO WIND DOWN LATE TONIGHT...WITH A BREAK EXPECTED ON
MONDAY...ALTHOUGH WE PROBABLY WILL NOT SEE MUCH SUN ON MONDAY...AS
STAGNANT LOW LVL FLOW LINGERS. HIGHS SHOULD CLIMB BACK INTO THE
MID 30S TO AROUND 40 AGAIN.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AS WAS THE CAST THE LAST COUPLE OF NIGHTS...NWP CONTINUES TO
INDICATE SRN STREAM S/WV TROF WILL OUTPACE ITS NRN STREAM
COUNTERPART. THE RESULT IS LOW PRES DEVELOPING OFF THE SOUTHEAST
COASTLINE...AND HEADING OUT TO SEA WITH A LATE CAPTURE THAT SWINGS
IT TOWARDS THE CANADIAN MARITIMES.
CONSENSUS IS THAT PCPN WILL ONLY BRUSH THE COAST...WITH THE
MIDCOAST PERHAPS SEEING A LITTLE LONGER DURATION AS LOW PRES CUTS
ACROSS BAROCLINIC ZONE. MODEL GUIDANCE HAS A VERY SHARP NRN EDGE
TO THE SATURATED SNOW GROWTH ZONE...SO WE WILL BE TREADING A VERY
FINE LINE OF SN OR NO SN HEADING INTO TUE. IN FACT...SFC TEMPS
WILL BE MARGINAL ENOUGH THAT SOME RNFL IS POSSIBLE NEAR THE COAST.
AS UPPER TROF CROSSES THE AREA THERE SHOULD BE ENOUGH FORCING AND
RESIDUAL MOISTURE TO BRING SCT SHSN TO MUCH OF THE AREA BEFORE
HIGH PRES BUILDS IN AND ENDS PCPN. THAT RIDGING WILL BE SHORT
LIVED THOUGH...AS NEXT LOW PRES DEVELOPS AND LIFTS INTO CANADA.
THIS WILL DRIVE A COLD FNT TOWARDS NEW ENGLAND. AFTER INITIAL
BURST OF WAA AHEAD OF THE LOW PRES...COLD WILL SLOWLY OOZE INTO
THE AREA AS FNT BECOMES ALIGNED WITH FLOW ALOFT. AS LONG AS
BOUNDARY REMAINS IN THE AREA IT WILL BE HARD TO RULE OUT
OVERRUNNING PCPN IN BROAD SWLY WAA REGIME.
LATE IN THE WEEK STRONG HIGH PRES WILL BUILD INTO THE
REGION...BEFORE WRN TROF EJECTS NEWD. GIVEN LOCATION OF HIGH
PRES...IT WOULD NOT BE SURPRISING TO SEE NWP TREND COOLER WITH
TIME...THOUGH THERE ARE SEVERAL DAYS BEFORE ANY DETAILS WILL
BECOME MORE CLEAR.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...SHOULD SEE ALL TERMINALS GET A PREIOD OF MVFR TO IFR
TODAY WITH SHSN INLAND...AND SHRA ON THE COAST. A STEADIER RA IS
EXPECTED AT KRKD...AND A STEADY MIX OF RASN AT KAUG. CONDITIONS
WILL IMPROVE LATE TONIGHT TO VFR FROM KPWM WWD...AND EVENTUALLY AT
KAUG/KRKD ON MONDAY.
LONG TERM...AREAS OF MVFR OR LOWER CONDITIONS WILL BE POSSIBLE TUE
INTO WED AS OCEAN LOW PRES PASS OUT TO SEA. COASTAL TERMINALS WILL
SEE LOWER CIGS AS WELL AS POSSIBLE SHSN LIMITING VSBYS. PASSAGE OF
UPPER TROF MAY ALSO RESULT IN SOME MTNS SHWRS INVOF OF KHIE.
&&
.MARINE...
SHORT TERM...SOUTHERLY SURGE IN WINDS OCCURRING ATTM AND COULD SEE
A FEW GUSTS UP TO 25 KT THRU SUNRISE. OTHERWISE...QUIET WEATHER
WITH VSBY RESTRICTIONS EXPECTED LATER TONIGHT THROUGH SUNDAY NIGHT
IN DEVELOPING RAIN AND SNOW.
LONG TERM...STILL SOME UNCERTAINTY REGARDING THE TRACK OF COASTAL
LOW PRES MIDWEEK. HOWEVER CONFIDENCE IS GROWING THAT SEAS WILL
BUILD TO AT OR ABOVE 5 FT FOR TUE AND WED. WINDS MORE THAN LIKELY
SHOULD REMAIN AT OR BELOW 25 KTS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...CEMPA
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS CARIBOU ME
630 AM EST SUN DEC 1 2013
.SYNOPSIS...
LOW PRESSURE IS EXPECTED TO CROSS THE STATE TODAY AND REDEVELOP IN
THE GULF OF MAINE TONIGHT, PASSING WELL E OF THE REGION ON MONDAY.
ANOTHER LOW MAY AFFECT THE REGION FROM THE SOUTH TOWARD THE
MIDDLE PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE: ADJUSTED THE PRECIP CHANCES LINING THEM UP W/THE RADAR
TRENDS AND OBS. KEPT THE HIGH PRECIP CHANCES(60-80%) TOWARD THE
EASTERN SIDE OF THE CWA AND SCALED THEM BACK FURTHER W THROUGH
THIS MORNING. REPORTS COMING SHOW AN INCH OR LESS OF ACCUMULATION
W/WHAT FELL OVERNIGHT
WEAK LOW PRES MOVING ACROSS THE EASTERN GREAT LAKES IS FCST TO
MOVE ACROSS SOUTHERN NEW ENGLAND THIS AFTERNOON AND THEN INTO THE
GULF OF MAINE. THE CONCERN IS WHERE TO DRAW THE RAIN/SNOW LINE AS
WAA MAKES ITS WAY TO THE BLYR. TEMPERATURES ARE FCST TO REACH INTO
THE UPPER 20S TO AROUND 30 ACROSS THE NORTHERN 1/2 OF THE CWA
WHILE LOW TO MID 30S ARE EXPECTED FOR CENTRAL AND DOWNEAST AREAS.
AN INVERTED TROF EXTENDING FROM THE LOW COMBINED W/SOME
FRONTOGENETICAL FORCING AT 1000-700MB WILL LEAD TO A REFORMATION
OF PRECIP AND AN ENHANCEMENT OF THE PRECIP. USING THE BUFKIT
PROFILES AND SOUNDINGS, THINKING HERE IS THAT SNOW WILL REDEVELOP
ACROSS PORTION OF NORTHEAST MAINE W/THE HEAVIEST AXIS ACROSS THE
HOULTON AND DANFORTH REGION W/LESS SNOW NORTH AND WEST. S OF OF
THE HOULTON-DANFORTH LINE, TEMPERATURES WILL WARM INTO THE MID 30S
TO ALLOW FOR SNOW TO MIX WITH AND CHANGEOVER TO RAIN. THIS IN TURN
WILL CUT DOWN ON SNOWFALL LATER THIS AFTERNOON INTO TONIGHT.
DECISION WAS TO GO AHEAD AND ADD NORTHERN PENOBSCOT AND SE
AROOSTOOK COUNTY IN THE WINTER WEATHER ADVISORY THROUGH MONDAY
MORNING DUE TO ENHANCED FRONTOGENTICAL FORCING LEADING TO HEAVY
SNOW BURSTS. LATEST SNOW TOTAL MAP SHOWS A GENERAL 4-8 INCHES IN
THE ADVISORY AREA W/1-4 INCHES N AND W. THE COAST AND EXTREME
EASTERN WASHINGTON COUNTY FROM MEDDYBEMPS TO EASTPORT WILL SEE
0.30 TO 0.70 INCHES OF RAINFALL AFTER SOME INITIAL SNOWFALL.
SNOW WILL CONTINUE INTO TONIGHT ACROSS THE NORTHEASTERN SECTION OF
MAINE INCLUDING CARIBOU-PRESQUE ISLE DOWN THROUGH DANFORTH. WEST
OF THIS AREA, LITTLE OR NO SNOW AND RAIN/SNOW S OF THIS AREA
W/RAIN FOR THE COAST AS THE WARM AIR IS FCST TO STAY IN. TEMPERATURES
WILL DROP BACK INTO THE UPPER TEENS AND LOWER 20S NORTH AND WEST
AND MID TO UPPER 20S FOR CENTRAL AREAS. LOW 30S FOR THE DOWNEAST
REGION INCLUDING THE COAST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
SNOW WILL CONTINUE TO WIND DOWN EARLY MONDAY AS THE INVERTED TROF
EXTENDING FROM THE CANADIAN MARITIMES THROUGH DOWNEAST MAINE MOVES
OFF TO THE NORTHEAST. THERE MAY STILL BE SOME LINGERING LIGHT SNOW
OR SNOW SHOWERS PARTICULARLY ACROSS EASTERN AREAS OTHERWISE EXPECT
MOSTLY CLOUDY SKIES ACROSS THE REGION. MONDAY NIGHT WILL BE MOSTLY
CLOUDY BUT DRY AS WEAK HIGH PRESSURE RIDGES DOWN FROM THE NORTH.
ATTENTION THEN TURNS TO ANOTHER LOW PRESSURE SYSTEM THAT WILL BE
MOVING NORTHEAST ACROSS THE WESTERN ATLANTIC. THIS SYSTEM MAY BRINGS
SOME PRECIPITATION TO THE REGION LATER TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MODELS SEEM TO BE COMING INTO BETTER AGREEMENT FOR THE NEXT SYSTEM
TUESDAY NIGHT AND WEDNESDAY. STILL SOME MODEL DIFFERENCES BUT THE
CONSENSUS SOLUTION IS FOR THE LOW TO TRACK FAR ENOUGH EAST THAT ANY
IMPACTS IN OUR REGION WOULD BE ACROSS DOWNEAST/EASTERN MAINE.
A WEAK BOUNDARY WILL CROSS THE REGION BY LATE WEEK WITH SOME
SNOW/RAIN SHOWERS POSSIBLE. AGAIN...WILL STICK CLOSE TO THE
SUPERBLEND.
HIGH PRESSURE WILL BUILD EAST TOWARD THE REGION BY SATURDAY.
&&
.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: MVFR W/PERIODS OF VFR THIS MORNING DROPPING TO MVFR AND
EVEN IFR LATER THIS MORNING ON INTO TONIGHT. SNOW ACROSS THE NORTHERN
TERMINALS W/SNOW TO RAIN FOR KBGR TO KBHB.
SHORT TERM: MVFR CONDS ARE POSSIBLE EARLY MONDAY THEN VFR CONDS
EXPECTED MONDAY NIGHT INTO TUESDAY. MVFR CONDS ARE POSSIBLE IN
SOME LIGHT PRECIP LATE TUESDAY AND INTO EARLY WEDNESDAY. VFR ON
THURSDAY.
&&
.MARINE...
NEAR TERM: DECIDED TO GO W/A SCA THROUGH LATE MORNING. WINDS
GUSTING TO 25 KTS AS LLVL JET OF 30 KT MOVES ACROSS THE WATERS.
THE GFS AND NAM AS WELL AS THE LATEST RAP MODEL PICK UP ON THIS
FEATURE. WINDS ARE FCST TO DROP OFF THIS AFTERNOON AS THE LLVL JET
SHIFTS TO THE E. SEAS ARE AT 5FT AND COULD TIP 6 FT ESPECIALLY AT
44027(JONESPORT) THIS MORNING. SEAS WILL GRADUALLY SUBSIDE TONIGHT
BELOW 4 FT.
SHORT TERM: WINDS/SEAS WILL BE BELOW SCA LEVELS MON AND MON NIGHT.
WIND/SEAS MAY INCREASE TO SCA LEVELS TUE/TUE NIGHT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR MEZ005-006-
011-016-017-032.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR
ANZ050>052.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT/DUDA
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
359 AM EST SUN DEC 1 2013
.SYNOPSIS...
LOW PRESSURE IS EXPECTED TO CROSS THE STATE TODAY AND REDEVELOP IN
THE GULF OF MAINE TONIGHT, PASSING WELL E OF THE REGION ON MONDAY.
ANOTHER LOW MAY AFFECT THE REGION FROM THE SOUTH TOWARD THE
MIDDLE PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
CHALLENGE TODAY INTO TONIGHT WILL BE THE EXTENT OF THE WARM AIR
AND SNOWFALL AMOUNTS.
THE FIRST BATCH OF SNOW ASSOCIATED W/WAA THIS MORNING WAS NEAR THE
MAINE-NEW BRUNSWICK BORDER PER RADAR LOOP. IR SATL IMAGERY SHOWED
BEST ENHANCEMENT LINING UP WELL W/HIGHER RADAR RETURNS IN THIS
REGION. ADJUSTMENTS WERE MADE TO THE SNOW IN AREAL COVERAGE
SHOWING 60-80% OVER THE EASTERN AREAS THIS MORNING. THIS MATCHES UP
WELL W/THE LATEST NAM12 AND RAP MODELS. AROUND AN INCH OF SNOW
CAN BE EXPECTED W/THIS FIRST BURST. WEAK LOW PRES MOVING ACROSS
THE EASTERN GREAT LAKES IS FCST TO MOVE ACROSS SOUTHERN NEW
ENGLAND THIS AFTERNOON AND THEN INTO THE GULF OF MAINE. THE
CONCERN IS WHERE TO DRAW THE RAIN/SNOW LINE AS WAA MAKES ITS WAY
TO THE BLYR. TEMPERATURES ARE FCST TO REACH INTO THE UPPER 20S TO
AROUND 30 ACROSS THE NORTHERN 1/2 OF THE CWA WHILE LOW TO MID 30S
ARE EXPECTED FOR CENTRAL AND DOWNEAST AREAS. AN INVERTED TROF
EXTENDING FROM THE LOW COMBINED W/SOME FRONTOGENETICAL FORCING AT
1000-700MB WILL LEAD TO A REFORMATION OF PRECIP AND AN ENHANCEMENT
OF THE PRECIP. USING THE BUFKIT PROFILES AND SOUNDINGS, THINKING
HERE IS THAT SNOW WILL REDEVELOP ACROSS PORTION OF NORTHEAST MAINE
W/THE HEAVIEST AXIS ACROSS THE HOULTON AND DANFORTH REGION W/LESS
SNOW NORTH AND WEST. S OF OF THE HOULTON-DANFORTH LINE,
TEMPERATURES WILL WARM INTO THE MID 30S TO ALLOW FOR SNOW TO MIX
WITH AND CHANGEOVER TO RAIN. THIS IN TURN WILL CUT DOWN ON
SNOWFALL LATER THIS AFTERNOON INTO TONIGHT. DECISION WAS TO GO
AHEAD AND ADD NORTHERN PENOBSCOT AND SE AROOSTOOK COUNTY IN THE
WINTER WEATHER ADVISORY THROUGH MONDAY MORNING DUE TO ENHANCED
FRONTOGENTICAL FORCING LEADING TO HEAVY SNOW BURSTS. LATEST SNOW
TOTAL MAP SHOWS A GENERAL 4-8 INCHES IN THE ADVISORY AREA W/1-4
INCHES N AND W. THE COAST AND EXTREME EASTERN WASHINGTON COUNTY
FROM MEDDYBEMPS TO EASTPORT WILL SEE 0.30 TO 0.70 INCHES OF
RAINFALL AFTER SOME INITIAL SNOWFALL.
SNOW WILL CONTINUE INTO TONIGHT ACROSS THE NORTHEASTERN SECTION OF
MAINE INCLUDING CARIBOU-PRESQUE ISLE DOWN THROUGH DANFORTH. WEST
OF THIS AREA, LITTLE OR NO SNOW AND RAIN/SNOW S OF THIS AREA
W/RAIN FOR THE COAST AS THE WARM AIR IS FCST TO STAY IN. TEMPERATURES
WILL DROP BACK INTO THE UPPER TEENS AND LOWER 20S NORTH AND WEST
AND MID TO UPPER 20S FOR CENTRAL AREAS. LOW 30S FOR THE DOWNEAST
REGION INCLUDING THE COAST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
SNOW WILL CONTINUE TO WIND DOWN EARLY MONDAY AS THE INVERTED TROF
EXTENDING FROM THE CANADIAN MARITIMES THROUGH DOWNEAST MAINE MOVES
OFF TO THE NORTHEAST. THERE MAY STILL BE SOME LINGERING LIGHT SNOW
OR SNOW SHOWERS PARTICULARLY ACROSS EASTERN AREAS OTHERWISE EXPECT
MOSTLY CLOUDY SKIES ACROSS THE REGION. MONDAY NIGHT WILL BE MOSTLY
CLOUDY BUT DRY AS WEAK HIGH PRESSURE RIDGES DOWN FROM THE NORTH.
ATTENTION THEN TURNS TO ANOTHER LOW PRESSURE SYSTEM THAT WILL BE
MOVING NORTHEAST ACROSS THE WESTERN ATLANTIC. THIS SYSTEM MAY BRINGS
SOME PRECIPITATION TO THE REGION LATER TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MODELS SEEM TO BE COMING INTO BETTER AGREEMENT FOR THE NEXT SYSTEM
TUESDAY NIGHT AND WEDNESDAY. STILL SOME MODEL DIFFERENCES BUT THE
CONSENSUS SOLUTION IS FOR THE LOW TO TRACK FAR ENOUGH EAST THAT ANY
IMPACTS IN OUR REGION WOULD BE ACROSS DOWNEAST/EASTERN MAINE.
A WEAK BOUNDARY WILL CROSS THE REGION BY LATE WEEK WITH SOME
SNOW/RAIN SHOWERS POSSIBLE. AGAIN...WILL STICK CLOSE TO THE
SUPERBLEND.
HIGH PRESSURE WILL BUILD EAST TOWARD THE REGION BY SATURDAY.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: MVFR W/PERIODS OF VFR THIS MORNING DROPPING TO MVFR AND
EVEN IFR LATER THIS MORNING ON INTO TONIGHT. SNOW ACROSS THE NORTHERN
TERMINALS W/SNOW TO RAIN FOR KBGR TO KBHB.
SHORT TERM: MVFR CONDS ARE POSSIBLE EARLY MONDAY THEN VFR CONDS
EXPECTED MONDAY NIGHT INTO TUESDAY. MVFR CONDS ARE POSSIBLE IN
SOME LIGHT PRECIP LATE TUESDAY AND INTO EARLY WEDNESDAY. VFR ON
THURSDAY.
&&
.MARINE...
NEAR TERM: DECIDED TO GO W/A SCA THROUGH LATE MORNING. WINDS
GUSTING TO 25 KTS AS LLVL JET OF 30 KT MOVES ACROSS THE WATERS.
THE GFS AND NAM AS WELL AS THE LATEST RAP MODEL PICK UP ON THIS
FEATURE. WINDS ARE FCST TO DROP OFF THIS AFTERNOON AS THE LLVL JET
SHIFTS TO THE E. SEAS ARE AT 5FT AND COULD TIP 6 FT ESPECIALLY AT
44027(JONESPORT) THIS MORNING. SEAS WILL GRADUALLY SUBSIDE TONIGHT
BELOW 4 FT.
SHORT TERM: WINDS/SEAS WILL BE BELOW SCA LEVELS MON AND MON NIGHT.
WIND/SEAS MAY INCREASE TO SCA LEVELS TUE/TUE NIGHT.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR MEZ005-006-
011-016-017-032.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR
ANZ050>052.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT/DUDA
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1247 AM EST SUN DEC 1 2013
.SYNOPSIS...
LOW PRESSURE IS EXPECTED TO CROSS THE STATE ON SUNDAY. ANOTHER
LOW MAY AFFECT THE REGION FROM THE SOUTH TOWARD THE MIDDLE PART OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATE...RAMPED UP SNOWFALL CHANCES TO 90% OR MORE ACROSS THE NORTHERN
1/2 OF THE CWA AS THE LATEST RADAR LOOPS SHOWED A DECENT SWATH OF
SNOW MOVING ACROSS THE REGION. DECIDED OF 40-60% FOR SNOW FROM
CENTRAL AND DOWNEAST AREAS. LIGHT ACCUMULATIONS ARE EXPECTED
THROUGH THE EARLY MORNING. THE LATEST HRRR AND RAP WERE DOING WELL
W/THE PLACEMENT OF THE SNOW. ADJUSTED THE HRLY TEMPERATURES TO
MATCH THE LATEST CONDITIONS. SOME COOLING STILL IS EXPECTED ACROSS
THE FAR NORTH AND WEST AS THIS FIRST BATCH OF SNOW PUSHES E.
WINTER WEATHER ADVISORIES REMAIN IN PLACE ATTM FOR INTERIOR
DOWNEAST MAINE W/SNOW TOTALS OF 3 TO 6 INCHES EXPECTED. SOME OF
THE LATEST NUMERICAL GUIDANCE IS SHOWING MORE SNOW IN EASTERN
MAINE THROUGH SUNDAY NIGHT. THIS WILL NEED TO RE-VISITED DURING
THE MORNING PACKAGE.
WEAK LOW PRESSURE WILL SLIDE EASTWARD ACROSS THE GREAT LAKES
INTO SUNDAY. AS SUCH, EXPECT LIGHT SNOW TO DEVELOP OVER THE
REGION FROM NORTHWEST TO SOUTHEAST TONIGHT AND CONTINUE THROUGH
THE DAY ON SUNDAY. MODEL GUIDANCE CONTINUES TO INDICATE THAT A
BAND OF MODERATE TO HEAVY SNOW WILL DEVELOP LATER SUNDAY INTO
SUNDAY NIGHT IN ASSOCIATION WITH AN INVERTED TROUGH THAT WILL SET
UP SOMEWHERE ALONG THE COAST. WHILE THE NAM HAS COME MORE INTO
LINE OVER THE PAST FEW RUNS, IT CONTINUES TO BE A NORTHERN OUTLIER
WITH THIS BAND OF SNOW, SO LEANED HEAVILY ON THE GEM, GFS, AND
ECMWF FOR THIS FORECAST PERIOD. THESE MODELS HAVE BEEN CONSISTENT
WITH THEIR PLACEMENT OF THE BAND OVER DOWNEAST MAINE, THOUGH THEY
HAVE WAFFLED A BIT WITH EXACTLY HOW HEAVY THE QPF WILL BE. HAVE
THEREFORE STUCK CLOSE TO THE PREVIOUS FORECAST AS UNCERTAINTY IS A
BIT HIGHER THAN ONE WOULD ANTICIPATE FOR A STORM EXPECTED IN THE
NEXT 24-36 HOURS. IN ADDITION TO THE PLACEMENT OF THE CONCENTRATED
BAND, ALSO COMPLICATING THE SNOWFALL TOTAL FORECAST IS THE FACT
THAT TEMPERATURES WILL BE WARM ENOUGH DURING THE AFTERNOON FOR THE
SNOW TO MIX WITH AND/OR CHANGE TO RAIN ACROSS SOUTHERN AND COASTAL
DOWNEAST AREAS, ESPECIALLY FROM BANGOR SOUTH. FOR NOW, SNOWFALL
TOTALS OF 3 TO 5 INCHES ARE EXPECTED FROM ALONG AND SOUTH OF A
HOULTON TO DOVER-FOXCROFT LINE, WITH LESSER AMOUNTS AS YOU NEAR
THE COAST. ISOLATED AMOUNTS OF 5+ INCHES ARE POSSIBLE, ESPECIALLY
OVER NORTHERN WASHINGTON COUNTY. GIVEN THESE AMOUNTS, HAVE ISSUED
A WINTER WEATHER ADVISORY FOR LATE TONIGHT THROUGH SUNDAY NIGHT
FOR PORTIONS OF WASHINGTON, HANCOCK, AND PENOBSCOT COUNTIES. NORTH
OF THIS AREA, 1 TO 3 INCHES OF SNOW WILL BE THE RULE, WITH 1 INCH
OR LESS OVER THE FAR NORTH AND WEST.
FOR SUNDAY NIGHT...THE MODEL GUIDANCE HAS REALLY SHOWED A TIGHTENING
OF THE PRECIPITATION GRADIENT ON THE BACKSIDE OF THE AFOREMENTIONED
SNOW BAND; IN FACT, MANY GIVE THE NORTHWESTERN THIRD OF OUR AREA A
TRACE OR LESS OF QPF LATE AFTER 7PM/00Z. HAVE THEREFORE PULLED BACK
TO CHANCE POPS IN THESE AREAS FOR LATER TOMORROW INTO TOMORROW
NIGHT, ALONG WITH LIGHTER SNOWFALL AMOUNTS. THE HEAVIER SNOW OVER
DOWNEAST WILL CONTINUE INTO THE FIRST PART OF THE EVENING, BUT WILL
GRADUALLY TAPER OFF TO LIGHT SNOW TOWARD MIDNIGHT.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
FOR THE SHORT RANGE...THE SUITE OF MODELS SHOW CONSIDERABLE SPREAD
WITH REGARD TO THE EXACT SCENARIO OF S/WVS XPCTD TO AFFECT OUR FA.
BEST WE CAN TELL...A WEAK (SECOND) S/WV WILL CROSS THE FA FROM SW
TO NE BRINGING SN/SHWRS OR A PD OF LGT SN TO THE FA. HI TEMPS
RECOVER WELL INTO THE 30S ACROSS ERN PTNS OF THE FA...EVEN AS
FAR AS NE AROOSTOOK COUNTY BY MON AFTN AS 925-850 MB TEMPS APCH
OR EVEN EXCEED 0 DEG C...SO SN COULD MIX WITH OR EVN CHG TO RN
SHWRS FOR A BRIEF TM MON AFTN. SNFL AMOUNTS MON COULD REACH UP
TO AN ADDITIONAL INCH OR SO.
ANY LEFT OVR SHWRS SHOULD BE ALL SN BY MID EVE MON AS SFC AND
TEMPS ALF COOL A LITTLE...BUT WITH LITTLE...IF ANY QPF XPCTD
MON NGT...ANY CORRESPONDING SNFL SHOULD BE NEGLIGIBLE THIS PD.
CLD CVR AND ERLY COMPONENT SFC WINDS SHOULD KEEP OVRNGT LOWS MILD
DURG THIS TM.
EVEN MORE UNCERTAINTY EXISTS WITH THE NEXT SERIES OF OF S/WVS AS
SPLIT IN THE FLOW ALF DEVELOPS OVR THE NE U.S. ON TUE. ANY LEAD
PRECIP WITH THESE SYSTEMS THAT ARRIVES MSLY BY TUE AFTN LOOKS TO
BE ON THE LGT SIDE ATTM. MORE SO...SFC AND 925-850 MB TEMPS WILL
EVEN BE MILDER THAN MON...SUGGESTING EVEN A GREATER POTENTIAL TO
GO OVR TO A PD OF RN SHWRS OVR ALL XCPT PERHAPS HIER TRRN OF NW
ME... REDUCING THE POTENTIAL OF ACCUMULATING SNFL ACROSS THE
REGION AS A WHOLE THIS PD.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MODEL DIVERGENCE IN THE LONG RANGE IS EVIDENT FROM THE START OF
THE EXTENDED PERIOD. THESE DIFFERENCES CAN BE SEEN IN THE
LOCATION/TIMING OF THE SURFACE LOW OFF THE COAST OF MAINE AND BY
THE STRENGTH OF THE UPPER LEVEL LOW. THESE DIFFERENCES APPEAR TO
BE ASSOCIATED WITH A TROUGH THAT WILL BE PROGRESSING EAST OUT OF
THE WESTERN PORTION OF THE US. THE 12Z GFS IS MORE PROGRESSIVE
WITH THE UPPER LEVEL LOW TO THE WEST THAN THE 00Z ECMWF. SINCE
THERE IS STILL SOME UNCERTAINTY WILL CONTINUE WITH THE SUPERBLEND.
THIS WILL BRING BEST CHANCES OF PRECIP ACROSS THE SOUTHEASTERN
PORTIONS OF THE STATE TUESDAY NIGHT INTO WEDNESDAY.
WEAK RIDGING WILL BUILD IN BEFORE THE SYSTEM TO THE WEST
APPROACHES ALLOWING FOR SOME BRIEF BREAK THURSDAY. THERE ARE
CERTAINLY STILL TIMING AND LOCATION DIFFERENCES IN THE GUIDANCE
THAT WILL NEED TO BE WORKED OUT FOR LATE NEXT WEEK. THIS PERIOD
WILL ALSO STICK WITH THE CONSENSUS/SUPERBLEND APPROACH. THIS WILL
BRING THE NEXT BEST CHANCE OF PRECIP FRIDAY INTO SATURDAY WITH
BEST CHANCES ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. HIGH
AND LOW TEMPERATURES WILL BE NEAR TO LITTLE ABOVE NORMAL FOR THE
PERIOD.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: VFR GOING TO MVFR OVERNIGHT AND DETERIORATE TO
IFR W/PERIODS OF LIFR AS SNOW SPREADS ACROSS THE REGION THROUGH
EARLY MORNING. THE SNOW AND IFR/LIFR CONDITIONS ARE EXPECTED TO
CONTINUE RIGHT THROUGH 00Z MONDAY, THOUGH KBGR AND KBHB WILL
TRANSITION OVER TO RAIN FOR A FEW HOURS SUNDAY AFTERNOON. IFR
CONDITIONS WILL POSSIBLY LIFT AT THE NORTHERN TERMINALS AFTER 00Z
MONDAY, BUT KHUL/KBGR/KBHB WILL REMAIN IFR THROUGH THE END OF THE
PERIOD.
SHORT TO LONG TERM: WE XPCT MVFR AT BEST OVR ALL OF THE TAF SITES
WITH PDS OF IFR IN SN/RN OR STEADY LGT SN/RN FROM TUE THRU THU.
&&
.MARINE...
NEAR TERM: SEAS ARE RUNNING 2 TO 3 FT AS OF 9 PM ON THE COASTAL
WATERS WITH A SSW WIND OF AROUND 15 KNOTS WITH GUSTS TO 20 KNOTS.
NEAR SCA CONDITIONS ARE EXPECTED LATE TONIGHT AND SUNDAY AS LOW
PRESSURE APPROACHES FROM THE NORTHWEST. SOUTH WINDS WILL INCREASE
AHEAD OF THIS LOW, WITH SOME GUSTS APPROACHING 25 KT. MEANWHILE,
SEAS WILL BUILD TO AROUND 4 FT. THESE CONDITIONS WILL IMPROVE
SUNDAY NIGHT AS THE WEAKENS. GIVEN THE BORDERLINE NATURE OF THE
WINDS AND WAVES, HAVE OPTED TO NOT ISSUE ANY HEADLINES AT THIS
TIME, BUT THE SITUATION WILL HAVE TO BE WATCHED CLOSELY.
SHORT TERM: INITIALLY NO HDLNS SHOULD BE NEEDED...THEN WINDS AND
SEAS INCREASE BEGINNING LATE MON NGT AS LOW PRES ORGANIZES S AND
E OF THE WATERS...POTENTIALLY REACHING SCA THRESHOLDS TUE AFTN...
THEN CONTG INTO WED MORN BEFORE SUBSIDING LATER WED. WE USED A BLEND
OF MODELS AND MOS GUIDANCE FOR WINDS AND BLENDED WW3 WITH SWAN NAM/GFS
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR MEZ011-016-
017-032.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1013 PM EST MON DEC 2 2013
.SYNOPSIS...
CLOUDY CONDITIONS EXPECTED THROUGH THE WEEK WITH A SLIGHT CHANCE
OF PRECIPITATION TONIGHT AND AGAIN ON WEDNESDAY NIGHT THROUGH
FRIDAY. WELL ABOVE NORMAL TEMPERATURES THIS WEEK WILL FALL TO
BELOW NORMAL BY THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
THE FIRST WAVE ALONG THE FRONT IS EXITING TO THE EAST...HAVING
MANAGED TO GENERATE ENOUGH LIFT LOCALLY TO JUST WET TO THE GROUND
FROM PITTSBURGH TO THE NORTHEAST. A BRIEF QUIET PERIOD LOOKS TO
FOLLOW IT ON RADAR AND REGIONAL SATELLITE IMAGERY. IN FACT...A BIT
OF PARTIAL CLEARING BETWEEN THE WAVES SEEMS TO HAVE ALLOWED SOME
TEMPERATURES TO FALL OFF A BIT MORE THAN EXPECTED. AS A RESULT AND
AFTER A SECOND LOOK AT RUC THERMAL PROFILES OVERNIGHT WITH A
SECOND INCOMING WAVE...IT SEEMS THINGS ACROSS THE NORTH COULD BE A
BIT MORE FAVORABLE FOR A SNOW FLAKE OR TWO MAKING IT OUT OF THE
CLOUDS.
RADAR COVERAGE WITH THE SECOND WAVE IS FAR MORE IMPRESSIVE THAN
ANY RECENT WEAK WAVE ALONG THIS FRONT...SO A MIX OF INTERMITTENT LIGHT
RAIN AND LIGHT SNOW SEEMS PROBABLE FOR THE CWA AT THE VERY LEAST
FROM PITTSBURGH WEST OVERNIGHT. FRIES
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
DRY AND MILD CONDITIONS EXPECTED UNDER SOUTHWESTERLY FLOW ALOFT
AHEAD OF THE NEXT FRONTAL SYSTEM TO IMPACT THE REGION...WITH
TEMPERATURES AROUND 10 DEGREES ABOVE NORMAL BY WEDNESDAY. WARM
FRONT TO PASS THROUGH WEDNESDAY NIGHT WITH TRAILING COLD FRONT
THROUGH BY THURSDAY EVENING BASED ON LATEST MODEL CONSENSUS.
PRECIPITATION WILL SPREAD OVER THE AREA WEDNESDAY AFTERNOON AHEAD
OF THE WARM FRONT WITH RELATIVELY LIGHT QPF AMOUNTS...BUT MORE
SIGNIFICANT PRECIPITATION LOOKS LIKELY JUST ALONG AND BEHIND THE
THE COLD FRONT. LATEST HPC GUIDANCE PROJECTS ONE INCH OF TOTAL QPF BY
THE WEEKEND IN GENERAL FOR THE AREA...WITH THE HIGHER AMOUNTS
POSSIBLE ACROSS SOUTHERN ZONES WHICH WILL HAVE MORE FAVORABLE
UPPER LEVEL SUPPORT. PRECIPITATION WILL FALL INITIALLY AS RAIN
AREAWIDE BEFORE TRANSITIONING TO SNOW FRIDAY NIGHT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
WITH MUCH COLDER AIR IN PLACE BEHIND THE COLD FRONT TEMPERATURES
WILL BE DRASTICALLY COOLER THAN EARLIER IN THE WEEK...WITH DAYTIME
MAX TEMPERATURES FORECAST TO LARGELY REMAIN BELOW FREEZING THROUGH
THE WEEKEND. ANOTHER FRONTAL SYSTEM WILL CROSS THE REGION SUNDAY
WITH SNOW LIKELY SUNDAY AFTERNOON THROUGH MONDAY.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
CONTINUING TO KEEP PCPN OUT OF TAFS, THOUGH A FEW SPRINKLES WILL
BE SCATTERED ABOUT. IF SHOWERS ARE MORE WIDESPREAD IN
COVERAGE...LOW MVFR OR IFR CIGS CANNOT BE RULED OUT. BROUGHT IN
SOME MVFR FOG LATE AS A COMPROMISE. ANY PRECIPITATION SHOULD MOVE
OUT BY TUESDAY MORNING...WITH RISING CEILINGS THROUGH THE DAY.
WIND WILL REMAIN LIGHT THROUGH THE PERIOD.
.OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
A GREATER CHANCE FOR WIDESPREAD RESTRICTIONS WILL BE WITH THE
FRONTAL BOUNDARY THAT IS EXPECTED TO STALL OVER THE REGION
WEDNESDAY NIGHT. SEVERAL SYSTEMS WILL THEN DEVELOP AND MOVE ALONG
THE NEARLY STATIONARY BOUNDARY...CONTINUING RESTRICTION CHANCES
THROUGH THE BEGINNING OF THE WEEKEND BEFORE CONDITIONS DRY OUT
SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
738 PM EST MON DEC 2 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 506 PM EST MON DEC 2 2013
MAIN FCST CONCERN IN THE SHORT TERM IS SNOW ACCUMULATIONS WITH A
RATHER PERSISTENT -SN REGIME SETTING UP.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW RELATIVELY ZONAL FLOW
ACROSS THE NRN PLAINS AND UPPER GREAT LAKES. ONE SHORTWAVE HAS MOVED
E OF UPPER MI...ANOTHER IS OVER THE ERN DAKOTAS/WRN MN WHILE A
WELL-DEFINED MID LEVEL LOW IS NOTED OVER THE PACIFIC NW. PCPN
TONIGHT/EARLY TUE WILL BE ASSOCIATED WITH THE SHORTWAVE HEADING INTO
MN...THEN ANOTHER ROUND OF FORCING MAY BEGIN TO OVERSPREAD THE AREA
LATER TUE AS PACIFIC NW SYSTEM EMERGES INTO THE NRN PLAINS.
RELATIVELY MODEST ISENTROPIC ASCENT/WAA REGIME AHEAD OF THE WRN MN
SHORTWAVE IS GENERATING AN AREA OF -SN FROM NE MN ACROSS FAR WRN
UPPER MI INTO NW WI. ANOTHER BAND OF SNOW IS LINED UP JUST AHEAD OF
THE SHORTWAVE TROF AXIS. AS SHORTWAVE AND ASSOCIATED ISENTROPIC
ASCENT SHIFT E...EXPECT -SN TO SPREAD GRADUALLY E ACROSS ROUGHLY THE
W HALF OF UPPER MI TONIGHT. BETTER ASCENT GENERALLY OCCURS OVER FAR
W INTO SRN UPPER MI...BUT TENDS TO WEAKEN WITH TIME...ESPECIALLY
FARTHER E AND NE...AS SHORTWAVE WEAKENS. MAY END UP WITH A PERIOD OF
STEADIER -SN OVER THE FAR W THIS EVENING UNDER WAA REGIME AND THEN
THERE WILL BE ANOTHER PUSH OF STEADIER -SN AS BAND OF SNOW JUST
AHEAD OF SHORTWAVE TROF AXIS SWINGS INTO THE AREA. IN THE END...
GREATEST SNOW ACCUMULATIONS TONIGHT THRU TUE MORNING WILL OCCUR OVER
THE FAR W AND TO SOME EXTENT TOWARD SCNTRL UPPER MI. UTILIZATION OF
MIXING RATIOS ON THE 290K SFC (ROUGHLY BTWN 700-750MB) SUGGESTS
POTENTIAL FOR 4-6 INCH ACCUMULATIONS ACROSS THE W AND SCNTRL TONIGHT
THRU TUE MORNING. HOWEVER...WITH A LACK OF FOCUSED UPWARD MOTION
THRU A RELATIVELY HIGH/NARROW DGZ...SNOW RATIOS WILL BE ON THE LOW
SIDE...PROBABLY SOMETHING LIKE 10-12 TO 1. ALSO...SINCE ISENTROPIC
ASCENT IS NEVER ESPECIALLY STRONG...SNOW ACCUMULATIONS WILL LIKELY
END UP BLO ADVY CRITERIA. ONLY PLACE THAT WILL BE CLOSE TO ADVY IS
IN THE KIWD VCNTY. FOR NOW...WILL HOLD OFF ANY HEADLINES AND MONITOR
TRENDS THIS EVENING. OVERALL TONIGHT/TUE MORNING...EXPECT MORE OF A
PERSISTENT -SN WITH NOT MUCH IN THE WAY OF NOTABLY HEAVIER PERIODS
OF SNOW.
ON TUE...AREA OF DIMINISHING -SN ASSOCIATED WITH WEAKENING SHORTWAVE
WILL CONTINUE TO LIFT N AND E. MEANWHILE...SYSTEM CURRENTLY OVER THE
PACIFIC NW WILL EMERGE OVER THE NRN PLAINS. AS IT DOES SO...
ISENTROPIC ASCENT MAY STRENGTHEN AGAIN IN THE AFTN OR INTO TUE
EVENING...THOUGH THERE IS SOME DISAGREEMENT ON HOW STRONG THE
ISENTROPIC ASCENT WILL BE. SO...AFTER DIMINISHING -SN INTO THE AFTN
HRS...-SN MAY PICK UP AGAIN FROM THE SW LATER IN THE AFTN. MAY SEE
AN INCH OR SO OF SNOW LATE IN THE DAY TOWARD THE WI BORDER.
SPECIAL WEATHER STATEMENT HAS BEEN UPDATED TO REFLECT THE LATEST
THINKING ON THE WINTRY WEATHER EXPECTED OVER THE NEXT FEW DAYS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 513 PM EST MON DEC 2 2013
SIGNIFICANT SNOWFALL IS POSSIBLE TUESDAY NIGHT INTO THURSDAY MORNING
FOR WEST AND CENTRAL UPPER MICHIGAN
AND THE SAGA CONTINUES...MODELS DISAGREEING ON HOW AND WHEN THE LOW
PRESSURE SYSTEM WILL CROSS UPPER MI. THOUGH ALL HAVE SIMILAR TRACKS
WITH SLIGHT DIFFERENCES...THE 12Z GFS/NAM AND THE 12Z GEM/12Z ECMWF
ARE WIDELY DIFFERENT IN TERMS OF TIMING.
ON THE TRACK OVERALL...MODELS TAKE THE LOW FROM THE CENTRAL PLAINS
INTO THE JAMES BAY/NORTHERN ONTARIO REGION. THE 12Z GEM/12Z
UKMET/12Z ECMWF TAKE THE LOW FURTHEST SOUTHEAST...MOVING FROM
SOUTHEASTERN WI TO EASTERN UPPER MI...THEN INTO ONTARIO SOUTH OF
JAMES BAY. THE GFS/NAM TAKE THE LOW TRACK FROM WESTERN WI INTO
CENTRAL UPPER MI...THEN JUST SOUTH OF JAMES BAY AND NORTHEAST OF
LAKE SUPERIOR.
TIMING WISE...THE 12 GFS/NAM HAVE A MUCH QUICKER SOLUTION THAN THE
ECMWF/GEM...AND THE UKMET IS SLIGHTLY SLOWER THAN ALL. FOR
EXAMPLE...WHEN THE GFS/NAM HAVE THE LOW SOUTH OF JAMES BAY...THE 12Z
ECMWF/12Z GEM ARE JUST CROSSING IT OVER LAKE SUPERIOR/EASTERN UPPER
MI. THE UKMET HAS IT OVER SOUTHEASTERN UPPER MI/NORTHERN LAKE MI.
OVERALL...SINCE CONSISTENCY WISE THE ECWMF SEEMS STEADIER...AND
BECAUSE OFTEN TIMES THE GFS SEEMS TO RUSH THINGS THROUGH/AMPLIFY
THINGS...OPTED TO LEAN TOWARDS THE SLOWER GEM/ECMWF SOLUTION FOR
TIMING. FOR THE EXACT TRACK OF THE LOW...USED A 12Z GEM/12Z ECMWF
COMPROMISE.
USING THE CHOSEN MODEL TRACKS/TIMING...A BROAD AREA OF 850MB WAA AND
ISENTROPIC ASCENT ON THE 290K SFC WILL BRING WIDESPREAD
PRECIPITATION ACROSS UPPER MICHIGAN AS THE SYSTEM APPROACHES TUESDAY
NIGHT THROUGH WEDNESDAY MORNING. SOUNDINGS SUGGEST THIS FIRST BURST
OF PRECIPITATION WILL BE IN THE FORM OF SNOW. BY WEDNESDAY
AFTERNOON...AS THE LOW REACHES IOWA AND ILLINOIS/SOUTHERN WI...WARM
MOIST AIR WRAPPING AROUND THE SURFACE LOW DEVELOPS A 700MB FGEN BAND
THAT ALIGNS ITSELF SOUTHWEST TO NORTHEAST...FROM SOUTHEASTERN MN TO
JUST NORTHEAST OF LAKE SUPERIOR...ACROSS THE WESTERN AND CENTRAL CWA.
BY 00Z THURSDAY SLIGHT DIFFERENCES IN THE TRACK OF THE LOW BETWEEN
THE GEM/ECMWF START TO AFFECT THE TEMPERATURE/PTYPE FORECAST. THE
12Z ECMWF CENTERS THE LOW OVER CENTRAL WI...WHICH BRINGS A NOSE OF
WARMER AIR SLIGHTLY FURTHER NORTH AND CENTRAL. THIS WOULD BRING
CHANCES FOR MIXED PRECIPITATION/RAIN INTO THE NORTH CENTRAL AND
EAST. THE GEM KEEPS THE LOW SOUTHEAST...CENTERED OVER SOUTHEASTERN
WI BY 00Z THUR AND NOT QUITE PULLING THAT WARMER AIR AROUND INTO THE
CENTRAL. THIS WOULD KEEP THE WEST AND NORTH CENTRAL ALL SNOW...AND
THE EAST A MIX/RAIN. BY 12Z THURSDAY HOWEVER...THE MODELS ALL AGREE
ON SNOW BEING THE PTYPE. THE EXACT TRACK WILL AFFECT WHAT TYPE OF
SNOWFALL AMOUNTS WE SEE. AGAIN...WENT WITH AN ECMWF/GEM COMPROMISE
FOR TEMPS/PTYPE...WHICH KEEPS THE PRECIPITATION SNOW FOR A MAJORITY
OF THE FORECAST AREA...ONLY MIXING/RAIN ACROSS THE FAR SOUTHEASTERN
CWA. OVERALL...ACCUMULATIONS COULD BE OVER 6-8 INCHES ACROSS THE
WEST AND CENTRAL U.P. FROM TUESDAY NIGHT INTO THURSDAY MORNING.
AS THE LOW MOVES OFF INTO ONTARIO JUST NORTHEAST OF LAKE SUPERIOR
BETWEEN 06Z AND 12Z THURSDAY...UPPER MICHIGAN IS QUICKLY BROUGHT
INTO AN AREA OF STRONG CAA ON WEST TO NORTHWEST WINDS. 850MB TEMPS
QUICKLY DIP INTO THE -15 TO -20C RANGE IN THE WAKE OF THE LOW...AND
ON ON WEST TO NORTHWEST WINDS LAKE EFFECT CHANCES QUICKLY BECOME THE
MAIN CONCERN. GRADUALLY AS THE LOW HOVERS OVER JAMES BAY AREA FRIDAY
AND SATURDAY...850MB TEMPS CONTINUE TO DROP...REACHING AS LOW AS
-22C...WITH THE KEWEENAW AND WESTERN UPPER MI IN THE COLDEST OF THAT
AIR. THIS WILL BRING VERY COLD TEMPERATURES TO UPPER MICHIGAN FRIDAY
NIGHT THROUGH SATURDAY NIGHT...WITH WIND CHILLS AS LOW AS -25C IN
SOME PLACES OUT WEST.
SATURDAY AND SUNDAY...HIGH PRESSURE STEADILY EXPANDING FROM THE
CANADIAN PRAIRIE...ACROSS THE GREAT LAKES...AND INTO THE ATLANTIC.
GENERALLY IN THIS TIME FRAME...WINDS ARE WESTERLY TO
NORTHWESTERLY...850MB TEMPS RANGE FROM -22C TO -15C...AND THERE ARE
SHORTWAVES ROUNDING THE LOW OVER JAMES BAY. THESE SHORTWAVES WILL
SERVE TO ASSIST THE EXPECTED LAKE EFFECT SNOW SHOWERS DURING THESE
PERIODS...WITH CHANCES LESSENING AS THE LOW DEPARTS AND THE HIGH
STRENGTHENS. SNOW ACCUMULATIONS COULD BE HAMPERED HOWEVER...AS THE
DGZ DIPS CLOSER TO THE GROUND WITH THE EXTREME COLD. ON MONDAY
MODELS DISAGREE SLIGHTLY ON ANOTHER AREA OF LOW PRESSURE MOVING INTO
THE GREAT LAKES REGION...SO KEPT CONSENSUS PRECIPITATION CHANCES
BEGINNING ACROSS THE NON-LAKE EFFECT AREAS AS IT APPROACHES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 717 PM EST MON DEC 2 2013
DISTURBANCE APPROACHING FROM THE NRN PLAINS WILL SPREAD -SN FROM W
TO E ACROSS THE AREA TONIGHT. WITH THE ONSET OF THE -SN...MARGINAL
VFR CONDITIONS WILL INITIALLY LOWER TO MVFR AND THEN TO IFR SEVERAL
HRS LATER. UPSLOPE E-SE FLOW AT KCMX/KSAW WILL LIKELY ALSO AID IN
DETERIORATING CONDITIONS AT THOSE SITES TONIGHT. MAY SEE SOME IMPROVEMENT
AT KIWD TUE MORNING AND AT KSAW TUE AFTERNOON AS STEADIER -SN SHIFTS
E AND NE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 506 PM EST MON DEC 2 2013
AS LOW PRES BEGINS TO ORGANIZE IN THE PLAINS AND HIGH PRES BUILDS
ACROSS CNTRL CANADA AND INTO NRN ONTARIO...E TO SE WINDS WILL BE ON
THE INCREASE TONIGHT...AND E WINDS WILL INCREASE FURTHER TUE. EXPECT
WINDS TO REACH GALE FORCE OVER WRN LAKE SUPERIOR TUE AFTN THU WED
MORNING AS TERRAIN SURROUNDING THE LAKE ENHANCES THE E FLOW. THE LOW
WILL MOVE ACROSS THE UPPER GREAT LAKES LATE WED. IN THE WAKE OF THE
LOW...VERY COLD AIR ADVECTING OVER THE RELATIVELY WARM WATERS WILL
INCREASE INSTABILITY AND RESULT IN W TO NW GALES AT TIMES FOR
PORTIONS OF LAKE SUPERIOR WED NIGHT/THU. CONTINUED FLOW OF VERY COLD
AIR MAY RESULT IN PERIODIC GALES EVEN THRU FRI/SAT. BUILDING WAVES
AND THE ARRIVAL OF THE ARCTIC AIR WILL ALSO CAUSE INCREASING
FREEZING SPRAY LATE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 1 PM EST /NOON CST/ TUESDAY TO 10 AM EST /9 AM
CST/ WEDNESDAY FOR LSZ162.
GALE WARNING FROM 4 PM TUESDAY TO 10 AM EST WEDNESDAY FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...MCD
AVIATION...VOSS
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1250 PM EST SUN DEC 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM EST SUN DEC 1 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER
THE UPR GRT LKS TO THE SW OF UPR TROF CENTERED OVER NRN QUEBEC. IN
THE WAKE OF DEPARTING SHRTWV MOVING THRU SW QUEBEC...A SHRTWV RDG IS
SLIDING SEWD THRU NW ONTARIO...SUPPORTING A SFC HI PRES OVER FAR NW
ONTARIO. CLOSER TO UPR MI...A LO PRES TROF IS APRNT NEAR THE LK SUP
SHORE OF UPR MI AND EXTENDING WNW IN THE MN ARROWHEAD. THIS TROF HAS
BEEN THE FOCUS FOR SOME BANDS OF HIER REFLECTIVITY SHOWN ON THE MQT
88D REFLECTIVITY WITH UPSLOPE N WINDS NEAR LK SUP. SINCE H85 TEMPS
ARE ONLY -7 TO -8C AND THE ACCOMPANYING MSTR IS RELATIVELY SHALLOW
AS DIAGNOSED FM THE MQT 88D VWP AS WELL AS THE 00Z INL RAOB...WHICH
SHOWS INVRN BASE NEAR H85 UNDER VERY DRY MID LVLS AHEAD OF APRCHG
SHRTWV RDG...ASSOCIATED PCPN HAS BEEN A MIX OF -SHSN AND SOME -FZDZ.
THE 00Z YPL RAOB SHOWS SHALLOW MSTR AS WELL BLO AN INVRN NEAR
H925...SO PLENTY OF LO CLDS EXTEND WELL N INTO ONTARIO. THE AIR IS
MUCH COLDER THERE WITH SFC TEMPS IN THE TEENS...SO SPOTTY LGT PCPN
IS IN THE FORM OF SN.
MAIN FCST CONCERN IN THE SHORT TERM IS THE POTENTIAL FOR SOME LGT
-SN AND -FZDZ.
TODAY...WITH APRCH OF SHRTWV RDG NOW IN NW ONTARIO...LARGER SCALE
QVECTOR DVGC/MID LVL DRYING IS FCST TO SLOWLY WEAKEN...BUT NOT
ELIMINATE ALTOGETHER...THE SFC TROF NOW OVER LK SUP AND INHIBIT ANY
LARGER SCALE PCPN. SFC HI PRES NOW OVER FAR NW ONTARIO IS PROGGED TO
DRIFT ONLY SLOWLY SE ACRS NRN ONTARIO...WITH THE CWA DOMINATED BY
WEAKENING AND SLOWLY VEERING LLVL NE FLOW. WL CONT TO CARRY SOME CHC
POPS NEAR LK SUP IN AREA THAT WL EXPERIENCE AN UPSLOPE WIND
COMPONENT NEAR LINGERING LO PRES TROF OVER THE NCENTRAL. WHETHER
THIS PCPN IS ALL -SN OR REMAINS MIXED WITH SOME -FZDZ IS THE PRIMARY
CONCERN. MODELS REMAIN INCONSISTNET ON FCST H85 TEMPS AND MSTR
DEPTH. FCST H85 TEMPS ARE FCST TO FALL TO ARND -9C BY THE 00Z
NAM/LOCAL WRF-ARW TO -11C BY THE GFS. GIVEN THE WEAKENING WINDS THAT
WL LIMIT LLVL CAD AND EXPECTED NEGATIVE DYNAMICS AS WELL AS UPSTREAM
RAOBS...PREFER THE SOMEWHAT WARMER H85 TEMPS AND SHALLOWER MSTR
PROFILE/LOWER INVRN BASE SHOWN BY THE 00Z LOCAL WRF-ARW MODEL. THIS
MODEL SHOWS THE UPSLOPE UVV AND INVRN BASE REMAINING NR 5K FT AGL
AND BLO THE DGZ... SO WL RETAIN A MIX OF -SN/-FZDZ THRU THE DAY.
MARGINAL H85 TEMPS RELATIVE TO LK WATER TEMP ARND 4C WL LIMIT ANY SN
ACCUM. WITH PLENTY OF LO CLDS...TEMPS SHOULD REBOUND ONLY SLIGHTLY
THRU THE DAY.
TNGT...VERY LGT LLVL WINDS ARE PROGGED TO SLOWLY VEER TO THE E AND
SE AS THE CENTER OF SFC HI PRES SHIFTS INTO QUEBEC. SUSPECT
LINGERING LK EFFECT PCPN WL DRIFT INTO THE KEWEENAW AS THE FLOW
GRDLY SHIFTS TO THE ESE. IN THE ABSENCE OF ANY DYNAMIC SUPPORT...
EXPECT THE INVRN BASE TO REMAIN NEAR 5K FT. AS POINTED OUT BY THE
DAYSHIFT...LK VORTICES OFTEN DVLP WITH THE FCST LGT LLVL WINDS. BUT
MARGINAL H85 TEMPS ARND -9C WL LIMIT THE INTENSITY OF ANY SHSN THAT
WOULD ACCOMPANY THESE FEATURES...AND THE LGT WINDS WL INHIBIT
BANDING. SO ANY SN ACCUMS SHOULD REMAIN LGT. SINCE THE H85 TEMPS WL
REMAIN MARGINAL FOR LES AND UPSLOPE OMEGA WL REMAIN BLO THE
DGZ...INCLUDED A MENTION OF FZDZ. LINGERING LO CLDS WL LIMIT THE
DIURNAL TEMP FALL. BEST CHC FOR SOMEWHAT LOWER TEMPS WL BE OVER THE
E WITH A RELATIVELY UNMODIFIED/DOWNSLOPE E FLOW OFF ONTARIO THAT
MIGHT ALLOW FOR SOME BREAKS IN THE SC.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 430 AM EST SUN DEC 1 2013
MONDAY THROUGH TUESDAY MORNING...UPPER LEVEL 500MB TROUGHING IS
EXPECTED TO REMAIN IN PLACE ACROSS THE CWA THROUGH THIS TIME PERIOD
AS A WEAK INVERTED RIDGE WEDGES IN ACROSS THE AREA AT THE SURFACE. A
SLIGHTLY DRYER AIRMASS WILL ALSO LINGER THROUGH TUESDAY MORNING
WHICH CAN BE SEEN BY ANALYZING 1000-500MB RH. THE NEXT SURFACE LOW
CAN BE SEEN PUSHING ACROSS THE NORTHERN ROCKIES MONDAY NIGHT AND
EJECTING INTO THE NORTHERN OR CENTRAL PLAINS TUESDAY MORNING AS A
MUCH DEEPER UPPER LEVEL 500MB TROUGH BUILDS IN OVER THE WESTERN U.S.
THERE ARE STILL SOME MODEL DIFFERENCE HOWEVER WITH THE 00Z GFS/NAM
BEING A BIT FASTER AND STRONGER WITH THIS LOW. THE 00Z GFS/NAM
PLACE THE SURFACE LOW ALONG THE NORTH AND SOUTH DAKOTA BORDER BY 12Z
ON TUESDAY. THE 00Z EC/GEM ARE THE SLOWER OF THE SOLUTIONS KEEPING
THE LOW A BIT FARTHER SOUTH AND REMAINING OVER THE CENTRAL PLAINS
JUST A BIT EAST OF THE ROCKIES. EITHER WAY...BOTH SOLUTIONS KEEP THE
PRECIPITATION TO THE WEST OF THE AREA THROUGH THIS TIME PERIOD.
LIGHT EASTERLY WINDS THROUGH MONDAY NIGHT WILL SLOWLY BECOME
SOUTHEASTERLY BY TUESDAY. THIS ALONG WITH H850 TEMPS AROUND -8 TO
-10 C WILL HELP TO KEEP CONDITIONS CLOUDY WITH VERY LIGHT
PRECIPITATION POSSIBLE...MAINLY OVER THE KEWEENAW PENINSULA.
TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...THIS TIME PERIOD REMAINS
UNCERTAIN WHICH HAS BEEN THE CASE OVER THE PAST SEVERAL DAYS...WITH
POOR MODEL AGREEMENT EVEN AS THIS TIME PERIOD IS RAPIDLY
APPROACHING...HOWEVER...THE 00Z EC TENDS TO BE TRENDING A BIT CLOSER
TO THE NAM AND GFS SOLUTIONS. THE GFS/NAM SOLUTIONS BRING INCREASED
MOISTURE AND PRECIPITATION INTO THE CWA BY 18Z TUESDAY...WHILE THE
EC/CANADIAN KEEP THE SYSTEM CENTERED OVER NORTHEASTERN KS DURING
THAT TIME FRAME. THE 00Z GFS PLACES THE SURFACE LOW AND VERTICALLY
STACKED CLOSED UPPER LEVEL 500MB LOW OVER WESTERN WI AT 00Z WED
WHILE THE 00Z EC HAS THE MORE ELONGATED SURFACE LOW OVER CENTRAL
IOWA INTO CENTRAL PLAINS. BY 18Z WED THE 00Z RUN OF THE GFS PUSHES
THE LOW TO THE NORTHEAST OF LAKE SUPERIOR WHILE THE EC IS JUST
PLACING THE SURFACE LOW AND UPPER LEVEL ENERGY INTO THE WESTERN
PORTION OF WI. DEFINITELY EASY TO SEE THAT THERE ARE STILL
SIGNIFICANT DIFFERENCES BETWEEN THESE MODELS...HOWEVER...A BETTER
SIGNAL EXISTS SINCE THE EC IS TRENDING A BIT CLOSES TO THE FASTER
SOLUTIONS...THE BEST IDEA FOR THE TIME BEING WILL BE MORE OF A
MIDDLE OF THE ROAD APPROACH...WITH A SLIGHT LEAN TOWARD THE FASTER
SOLUTIONS. THIS WOULD FAVOR A LATE TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT TIME FRAME FOR THE MORE CONCENTRATED AREA OF PRECIPITATION.
SOUNDINGS FOR THIS TIME PERIOD INDICATE WARMER AIR LIFTING NORTHWARD
ON THE EAST SIDE OF THE LOW HELPING TO TRANSITION THE PRECIPITATION
OVER TO A RAIN SNOW MIXTURE FOR AT LEAST THE EASTERN HALF OF THE
UPPER PENINSULA AS A FAIRLY DEEP WARM LAYER BUILDS IN THROUGH MUCH
OF THE BOUNDARY LAYER. THE FAR WESTERN PORTION OF THE U.P. MAY END
UP SEEING MAINLY SNOW AS SHOWN BY ANALYZING BOTH THE EC AND GFS
PROFILES. IN ANY CASE THIS SYSTEM WILL BE CLOSELY WATCHED OVER THE
NEXT SEVERAL MODEL RUNS TO SEE IF BETTER UPPER AIR SAMPLING CAN
ENTERTAIN GREATER MODEL AGREEMENT.
THURSDAY THROUGH SATURDAY...ATTENTION TURNS TO A POTENTIALLY
PROLONGED PERIOD OF LAKE EFFECT SNOW. MODELS ACTUALLY BECOME IN
BETTER AGREEMENT WITH THE SYSTEM DURING THIS TIME FRAME. EACH OF THE
MODELS SHIFT THE SURFACE LOW NORTHEASTWARD TO NEAR JAMES BY BY 12Z
THURSDAY. AS THIS HAPPENS WINDS WILL SHIFT TO THE WEST ALLOWING LAKE
EFFECT SNOW TO DEVELOP IN AREAS FAVORED BY THAT PARTICULAR WIND
DIRECTION. THURSDAY THROUGH THURSDAY NIGHT THE LAKE EFFECT SNOW WILL
PROBABLY JUST BE STARTING ACROSS THE AREA...BUT SHOULD REMAIN LIGHT.
TRIED TO TREND THE LES CHANCES UPWARD FRIDAY THROUGH SATURDAY AS AN
UPPER LEVEL TROUGH/SHORTWAVE AND INCREASED MOISTURE SHIFTS INTO THE
AREA...ALLOWING FOR ENHANCED LIFT FOR LES TO DEVELOP. ITS STILL A
BIT TOO EARLY TO TELL FOR SURE ABOUT THE OVERALL SNOWFALL
TOTALS...BUT IT DOES LOOK LIKE FRIDAY INTO SATURDAY WILL BE SNOW FOR
WESTERLY WIND FAVORED AREAS OF THE UPPER PENINSULA. AS EARLIER SHIFT
STATED THE SNOW TO LIQUID RATIOS WILL LIKELY BE SLIGHTLY LOWER THAN
USUAL FOR LES AS THE DGZ IS FAIRLY SHALLOW AND FAIRLY LOW IN THE
ATMOSPHERE...WHICH TENDS TO INHIBIT THE MORE FAVORABLE GROWTH RATES
FOR SNOW. STAY TUNED THOUGH AS THIS LES EVENT GETS CLOSER TOWARD THE
WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1248 PM EST SUN DEC 1 2013
A MVFR/VFR STRATUS DECK COVERS ALL OF UPPER MICHIGAN THIS AFTERNOON
AND WITH LIGHT NORTHERLY WINDS...EXPECT THAT TO CONTINUE INTO THE
EVENING HOURS. THERE COULD BE SOME BRIEF VISIBILITY RESTRICTIONS AS
KSAW LATE THIS AFTERNOON...AS A LAKE EFFECT BAND IN EASTERN ALGER
COUNTY DROPS SOUTHEAST. LATEST TRENDS ARE FOR SOME WEAKENING AND
WITH WINDS ALOFT WEAKENING AND BECOMING VARIABLE...IT MAY NOT EVEN
MAKE IT THERE. AS LOW LEVEL WINDS BEGIN TO TRANSITION TO THE SOUTH
THIS EVENING AND OVERNIGHT...EXPECT THE LINGERING LAKE EFFECT TO
SHIFT NORTH AND POTENTIALLY BRUSH KCMX. THIS SOUTHERLY WIND WILL
LIKELY LEAD TO CEILINGS RISING TOWARDS VFR OVERNIGHT INTO MONDAY
MORNING...BUT CONFIDENCE IS VERY LOW ON HOW QUICKLY THAT WILL OCCUR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 430 AM EST SUN DEC 1 2013
EXPECT NE WINDS UP TO 20 KTS EARLY THIS MORNING TO DIMINISH UNDER
15 KTS AND SLOWLY VEER INTO MON AS A WEAK PRES GRADIENT EXTENDING S
FROM HI PRES MOVING THRU ONTARIO DOMINATES THE UPPER LAKES. STRONGER
E TO SE WINDS UP TO 25 TO PERHAPS 30 KTS WILL THEN DEVELOP INTO MID
WEEK AS THE GRADIENT SHARPENS OVER LAKE SUP BETWEEN THE HI PRES
SHIFTING INTO QUEBEC AND LO PRES MOVING NE FROM THE PLAINS. THERE
WILL BE A SHARP WIND SHIFT TO THE WNW BY THU FOLLOWING THE PASSAGE
OF THE LO TO THE NE. DEPENDING ON THE TRACK AND INTENSITY OF THIS
LO...THERE COULD BE A W GALE ON THU INTO FRI.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KEC
AVIATION...SRF
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
641 AM EST SUN DEC 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM EST SUN DEC 1 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER
THE UPR GRT LKS TO THE SW OF UPR TROF CENTERED OVER NRN QUEBEC. IN
THE WAKE OF DEPARTING SHRTWV MOVING THRU SW QUEBEC...A SHRTWV RDG IS
SLIDING SEWD THRU NW ONTARIO...SUPPORTING A SFC HI PRES OVER FAR NW
ONTARIO. CLOSER TO UPR MI...A LO PRES TROF IS APRNT NEAR THE LK SUP
SHORE OF UPR MI AND EXTENDING WNW IN THE MN ARROWHEAD. THIS TROF HAS
BEEN THE FOCUS FOR SOME BANDS OF HIER REFLECTIVITY SHOWN ON THE MQT
88D REFLECTIVITY WITH UPSLOPE N WINDS NEAR LK SUP. SINCE H85 TEMPS
ARE ONLY -7 TO -8C AND THE ACCOMPANYING MSTR IS RELATIVELY SHALLOW
AS DIAGNOSED FM THE MQT 88D VWP AS WELL AS THE 00Z INL RAOB...WHICH
SHOWS INVRN BASE NEAR H85 UNDER VERY DRY MID LVLS AHEAD OF APRCHG
SHRTWV RDG...ASSOCIATED PCPN HAS BEEN A MIX OF -SHSN AND SOME -FZDZ.
THE 00Z YPL RAOB SHOWS SHALLOW MSTR AS WELL BLO AN INVRN NEAR
H925...SO PLENTY OF LO CLDS EXTEND WELL N INTO ONTARIO. THE AIR IS
MUCH COLDER THERE WITH SFC TEMPS IN THE TEENS...SO SPOTTY LGT PCPN
IS IN THE FORM OF SN.
MAIN FCST CONCERN IN THE SHORT TERM IS THE POTENTIAL FOR SOME LGT
-SN AND -FZDZ.
TODAY...WITH APRCH OF SHRTWV RDG NOW IN NW ONTARIO...LARGER SCALE
QVECTOR DVGC/MID LVL DRYING IS FCST TO SLOWLY WEAKEN...BUT NOT
ELIMINATE ALTOGETHER...THE SFC TROF NOW OVER LK SUP AND INHIBIT ANY
LARGER SCALE PCPN. SFC HI PRES NOW OVER FAR NW ONTARIO IS PROGGED TO
DRIFT ONLY SLOWLY SE ACRS NRN ONTARIO...WITH THE CWA DOMINATED BY
WEAKENING AND SLOWLY VEERING LLVL NE FLOW. WL CONT TO CARRY SOME CHC
POPS NEAR LK SUP IN AREA THAT WL EXPERIENCE AN UPSLOPE WIND
COMPONENT NEAR LINGERING LO PRES TROF OVER THE NCENTRAL. WHETHER
THIS PCPN IS ALL -SN OR REMAINS MIXED WITH SOME -FZDZ IS THE PRIMARY
CONCERN. MODELS REMAIN INCONSISTNET ON FCST H85 TEMPS AND MSTR
DEPTH. FCST H85 TEMPS ARE FCST TO FALL TO ARND -9C BY THE 00Z
NAM/LOCAL WRF-ARW TO -11C BY THE GFS. GIVEN THE WEAKENING WINDS THAT
WL LIMIT LLVL CAD AND EXPECTED NEGATIVE DYNAMICS AS WELL AS UPSTREAM
RAOBS...PREFER THE SOMEWHAT WARMER H85 TEMPS AND SHALLOWER MSTR
PROFILE/LOWER INVRN BASE SHOWN BY THE 00Z LOCAL WRF-ARW MODEL. THIS
MODEL SHOWS THE UPSLOPE UVV AND INVRN BASE REMAINING NR 5K FT AGL
AND BLO THE DGZ... SO WL RETAIN A MIX OF -SN/-FZDZ THRU THE DAY.
MARGINAL H85 TEMPS RELATIVE TO LK WATER TEMP ARND 4C WL LIMIT ANY SN
ACCUM. WITH PLENTY OF LO CLDS...TEMPS SHOULD REBOUND ONLY SLIGHTLY
THRU THE DAY.
TNGT...VERY LGT LLVL WINDS ARE PROGGED TO SLOWLY VEER TO THE E AND
SE AS THE CENTER OF SFC HI PRES SHIFTS INTO QUEBEC. SUSPECT
LINGERING LK EFFECT PCPN WL DRIFT INTO THE KEWEENAW AS THE FLOW
GRDLY SHIFTS TO THE ESE. IN THE ABSENCE OF ANY DYNAMIC SUPPORT...
EXPECT THE INVRN BASE TO REMAIN NEAR 5K FT. AS POINTED OUT BY THE
DAYSHIFT...LK VORTICES OFTEN DVLP WITH THE FCST LGT LLVL WINDS. BUT
MARGINAL H85 TEMPS ARND -9C WL LIMIT THE INTENSITY OF ANY SHSN THAT
WOULD ACCOMPANY THESE FEATURES...AND THE LGT WINDS WL INHIBIT
BANDING. SO ANY SN ACCUMS SHOULD REMAIN LGT. SINCE THE H85 TEMPS WL
REMAIN MARGINAL FOR LES AND UPSLOPE OMEGA WL REMAIN BLO THE
DGZ...INCLUDED A MENTION OF FZDZ. LINGERING LO CLDS WL LIMIT THE
DIURNAL TEMP FALL. BEST CHC FOR SOMEWHAT LOWER TEMPS WL BE OVER THE
E WITH A RELATIVELY UNMODIFIED/DOWNSLOPE E FLOW OFF ONTARIO THAT
MIGHT ALLOW FOR SOME BREAKS IN THE SC.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 430 AM EST SUN DEC 1 2013
MONDAY THROUGH TUESDAY MORNING...UPPER LEVEL 500MB TROUGHING IS
EXPECTED TO REMAIN IN PLACE ACROSS THE CWA THROUGH THIS TIME PERIOD
AS A WEAK INVERTED RIDGE WEDGES IN ACROSS THE AREA AT THE SURFACE. A
SLIGHTLY DRYER AIRMASS WILL ALSO LINGER THROUGH TUESDAY MORNING
WHICH CAN BE SEEN BY ANALYZING 1000-500MB RH. THE NEXT SURFACE LOW
CAN BE SEEN PUSHING ACROSS THE NORTHERN ROCKIES MONDAY NIGHT AND
EJECTING INTO THE NORTHERN OR CENTRAL PLAINS TUESDAY MORNING AS A
MUCH DEEPER UPPER LEVEL 500MB TROUGH BUILDS IN OVER THE WESTERN U.S.
THERE ARE STILL SOME MODEL DIFFERENCE HOWEVER WITH THE 00Z GFS/NAM
BEING A BIT FASTER AND STRONGER WITH THIS LOW. THE 00Z GFS/NAM
PLACE THE SURFACE LOW ALONG THE NORTH AND SOUTH DAKOTA BORDER BY 12Z
ON TUESDAY. THE 00Z EC/GEM ARE THE SLOWER OF THE SOLUTIONS KEEPING
THE LOW A BIT FARTHER SOUTH AND REMAINING OVER THE CENTRAL PLAINS
JUST A BIT EAST OF THE ROCKIES. EITHER WAY...BOTH SOLUTIONS KEEP THE
PRECIPITATION TO THE WEST OF THE AREA THROUGH THIS TIME PERIOD.
LIGHT EASTERLY WINDS THROUGH MONDAY NIGHT WILL SLOWLY BECOME
SOUTHEASTERLY BY TUESDAY. THIS ALONG WITH H850 TEMPS AROUND -8 TO
-10 C WILL HELP TO KEEP CONDITIONS CLOUDY WITH VERY LIGHT
PRECIPITATION POSSIBLE...MAINLY OVER THE KEWEENAW PENINSULA.
TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...THIS TIME PERIOD REMAINS
UNCERTAIN WHICH HAS BEEN THE CASE OVER THE PAST SEVERAL DAYS...WITH
POOR MODEL AGREEMENT EVEN AS THIS TIME PERIOD IS RAPIDLY
APPROACHING...HOWEVER...THE 00Z EC TENDS TO BE TRENDING A BIT CLOSER
TO THE NAM AND GFS SOLUTIONS. THE GFS/NAM SOLUTIONS BRING INCREASED
MOISTURE AND PRECIPITATION INTO THE CWA BY 18Z TUESDAY...WHILE THE
EC/CANADIAN KEEP THE SYSTEM CENTERED OVER NORTHEASTERN KS DURING
THAT TIME FRAME. THE 00Z GFS PLACES THE SURFACE LOW AND VERTICALLY
STACKED CLOSED UPPER LEVEL 500MB LOW OVER WESTERN WI AT 00Z WED
WHILE THE 00Z EC HAS THE MORE ELONGATED SURFACE LOW OVER CENTRAL
IOWA INTO CENTRAL PLAINS. BY 18Z WED THE 00Z RUN OF THE GFS PUSHES
THE LOW TO THE NORTHEAST OF LAKE SUPERIOR WHILE THE EC IS JUST
PLACING THE SURFACE LOW AND UPPER LEVEL ENERGY INTO THE WESTERN
PORTION OF WI. DEFINITELY EASY TO SEE THAT THERE ARE STILL
SIGNIFICANT DIFFERENCES BETWEEN THESE MODELS...HOWEVER...A BETTER
SIGNAL EXISTS SINCE THE EC IS TRENDING A BIT CLOSES TO THE FASTER
SOLUTIONS...THE BEST IDEA FOR THE TIME BEING WILL BE MORE OF A
MIDDLE OF THE ROAD APPROACH...WITH A SLIGHT LEAN TOWARD THE FASTER
SOLUTIONS. THIS WOULD FAVOR A LATE TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT TIME FRAME FOR THE MORE CONCENTRATED AREA OF PRECIPITATION.
SOUNDINGS FOR THIS TIME PERIOD INDICATE WARMER AIR LIFTING NORTHWARD
ON THE EAST SIDE OF THE LOW HELPING TO TRANSITION THE PRECIPITATION
OVER TO A RAIN SNOW MIXTURE FOR AT LEAST THE EASTERN HALF OF THE
UPPER PENINSULA AS A FAIRLY DEEP WARM LAYER BUILDS IN THROUGH MUCH
OF THE BOUNDARY LAYER. THE FAR WESTERN PORTION OF THE U.P. MAY END
UP SEEING MAINLY SNOW AS SHOWN BY ANALYZING BOTH THE EC AND GFS
PROFILES. IN ANY CASE THIS SYSTEM WILL BE CLOSELY WATCHED OVER THE
NEXT SEVERAL MODEL RUNS TO SEE IF BETTER UPPER AIR SAMPLING CAN
ENTERTAIN GREATER MODEL AGREEMENT.
THURSDAY THROUGH SATURDAY...ATTENTION TURNS TO A POTENTIALLY
PROLONGED PERIOD OF LAKE EFFECT SNOW. MODELS ACTUALLY BECOME IN
BETTER AGREEMENT WITH THE SYSTEM DURING THIS TIME FRAME. EACH OF THE
MODELS SHIFT THE SURFACE LOW NORTHEASTWARD TO NEAR JAMES BY BY 12Z
THURSDAY. AS THIS HAPPENS WINDS WILL SHIFT TO THE WEST ALLOWING LAKE
EFFECT SNOW TO DEVELOP IN AREAS FAVORED BY THAT PARTICULAR WIND
DIRECTION. THURSDAY THROUGH THURSDAY NIGHT THE LAKE EFFECT SNOW WILL
PROBABLY JUST BE STARTING ACROSS THE AREA...BUT SHOULD REMAIN LIGHT.
TRIED TO TREND THE LES CHANCES UPWARD FRIDAY THROUGH SATURDAY AS AN
UPPER LEVEL TROUGH/SHORTWAVE AND INCREASED MOISTURE SHIFTS INTO THE
AREA...ALLOWING FOR ENHANCED LIFT FOR LES TO DEVELOP. ITS STILL A
BIT TOO EARLY TO TELL FOR SURE ABOUT THE OVERALL SNOWFALL
TOTALS...BUT IT DOES LOOK LIKE FRIDAY INTO SATURDAY WILL BE SNOW FOR
WESTERLY WIND FAVORED AREAS OF THE UPPER PENINSULA. AS EARLIER SHIFT
STATED THE SNOW TO LIQUID RATIOS WILL LIKELY BE SLIGHTLY LOWER THAN
USUAL FOR LES AS THE DGZ IS FAIRLY SHALLOW AND FAIRLY LOW IN THE
ATMOSPHERE...WHICH TENDS TO INHIBIT THE MORE FAVORABLE GROWTH RATES
FOR SNOW. STAY TUNED THOUGH AS THIS LES EVENT GETS CLOSER TOWARD THE
WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 641 AM EST SUN DEC 1 2013
EXPECT MVFR CIGS TO PREDOMINATE AT ALL 3 TAF SITES THIS FCST PERIOD
WITH RELATIVELY SHALLOW MOIST LYR TRAPPED BLO SUBSIDENCE INVRN
ASSOCIATED WITH HI PRES OVER ONTARIO. THERE MAY ALSO BE SOME -SN AND
PERHAPS SOME -FZDZ MAINLY THIS MRNG AT IWD AND SAW IN THE PRESENCE
OF AN UPSLOPE N-NE WIND OFF LK SUP ON THE SRN FLANK OF THE HI TO THE
N. BUT AS THE WIND DIMINISHES AND SLOWLY VEERS TO A MORE ESE
DIRECTION BY THIS EVNG...THE PCPN SHOULD DIMINISH AT THESE LOCATIONS
AND PERHAPS SHIFT INTO CMX. DOWNSLOPE NATURE OF THIS FLOW INTO IWD
AND PERSISTENT SUBSIDENCE MAY CAUSE THE LO CLDS TO BREAK UP AT THIS
SITE LATER TNGT...BUT LGT WIND SPEEDS MAY CAUSE THIS DOWNSLOPE
COMPONENT TO BE NEGLIGIBLE. SO MAINTAINED MVFR FCST FOR NOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 430 AM EST SUN DEC 1 2013
EXPECT NE WINDS UP TO 20 KTS EARLY THIS MORNING TO DIMINISH UNDER
15 KTS AND SLOWLY VEER INTO MON AS A WEAK PRES GRADIENT EXTENDING S
FROM HI PRES MOVING THRU ONTARIO DOMINATES THE UPPER LAKES. STRONGER
E TO SE WINDS UP TO 25 TO PERHAPS 30 KTS WILL THEN DEVELOP INTO MID
WEEK AS THE GRADIENT SHARPENS OVER LAKE SUP BETWEEN THE HI PRES
SHIFTING INTO QUEBEC AND LO PRES MOVING NE FROM THE PLAINS. THERE
WILL BE A SHARP WIND SHIFT TO THE WNW BY THU FOLLOWING THE PASSAGE
OF THE LO TO THE NE. DEPENDING ON THE TRACK AND INTENSITY OF THIS
LO...THERE COULD BE A W GALE ON THU INTO FRI.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KEC
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
432 AM EST SUN DEC 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM EST SUN DEC 1 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER
THE UPR GRT LKS TO THE SW OF UPR TROF CENTERED OVER NRN QUEBEC. IN
THE WAKE OF DEPARTING SHRTWV MOVING THRU SW QUEBEC...A SHRTWV RDG IS
SLIDING SEWD THRU NW ONTARIO...SUPPORTING A SFC HI PRES OVER FAR NW
ONTARIO. CLOSER TO UPR MI...A LO PRES TROF IS APRNT NEAR THE LK SUP
SHORE OF UPR MI AND EXTENDING WNW IN THE MN ARROWHEAD. THIS TROF HAS
BEEN THE FOCUS FOR SOME BANDS OF HIER REFLECTIVITY SHOWN ON THE MQT
88D REFLECTIVITY WITH UPSLOPE N WINDS NEAR LK SUP. SINCE H85 TEMPS
ARE ONLY -7 TO -8C AND THE ACCOMPANYING MSTR IS RELATIVELY SHALLOW
AS DIAGNOSED FM THE MQT 88D VWP AS WELL AS THE 00Z INL RAOB...WHICH
SHOWS INVRN BASE NEAR H85 UNDER VERY DRY MID LVLS AHEAD OF APRCHG
SHRTWV RDG...ASSOCIATED PCPN HAS BEEN A MIX OF -SHSN AND SOME -FZDZ.
THE 00Z YPL RAOB SHOWS SHALLOW MSTR AS WELL BLO AN INVRN NEAR
H925...SO PLENTY OF LO CLDS EXTEND WELL N INTO ONTARIO. THE AIR IS
MUCH COLDER THERE WITH SFC TEMPS IN THE TEENS...SO SPOTTY LGT PCPN
IS IN THE FORM OF SN.
MAIN FCST CONCERN IN THE SHORT TERM IS THE POTENTIAL FOR SOME LGT
-SN AND -FZDZ.
TODAY...WITH APRCH OF SHRTWV RDG NOW IN NW ONTARIO...LARGER SCALE
QVECTOR DVGC/MID LVL DRYING IS FCST TO SLOWLY WEAKEN...BUT NOT
ELIMINATE ALTOGETHER...THE SFC TROF NOW OVER LK SUP AND INHIBIT ANY
LARGER SCALE PCPN. SFC HI PRES NOW OVER FAR NW ONTARIO IS PROGGED TO
DRIFT ONLY SLOWLY SE ACRS NRN ONTARIO...WITH THE CWA DOMINATED BY
WEAKENING AND SLOWLY VEERING LLVL NE FLOW. WL CONT TO CARRY SOME CHC
POPS NEAR LK SUP IN AREA THAT WL EXPERIENCE AN UPSLOPE WIND
COMPONENT NEAR LINGERING LO PRES TROF OVER THE NCENTRAL. WHETHER
THIS PCPN IS ALL -SN OR REMAINS MIXED WITH SOME -FZDZ IS THE PRIMARY
CONCERN. MODELS REMAIN INCONSISTNET ON FCST H85 TEMPS AND MSTR
DEPTH. FCST H85 TEMPS ARE FCST TO FALL TO ARND -9C BY THE 00Z
NAM/LOCAL WRF-ARW TO -11C BY THE GFS. GIVEN THE WEAKENING WINDS THAT
WL LIMIT LLVL CAD AND EXPECTED NEGATIVE DYNAMICS AS WELL AS UPSTREAM
RAOBS...PREFER THE SOMEWHAT WARMER H85 TEMPS AND SHALLOWER MSTR
PROFILE/LOWER INVRN BASE SHOWN BY THE 00Z LOCAL WRF-ARW MODEL. THIS
MODEL SHOWS THE UPSLOPE UVV AND INVRN BASE REMAINING NR 5K FT AGL
AND BLO THE DGZ... SO WL RETAIN A MIX OF -SN/-FZDZ THRU THE DAY.
MARGINAL H85 TEMPS RELATIVE TO LK WATER TEMP ARND 4C WL LIMIT ANY SN
ACCUM. WITH PLENTY OF LO CLDS...TEMPS SHOULD REBOUND ONLY SLIGHTLY
THRU THE DAY.
TNGT...VERY LGT LLVL WINDS ARE PROGGED TO SLOWLY VEER TO THE E AND
SE AS THE CENTER OF SFC HI PRES SHIFTS INTO QUEBEC. SUSPECT
LINGERING LK EFFECT PCPN WL DRIFT INTO THE KEWEENAW AS THE FLOW
GRDLY SHIFTS TO THE ESE. IN THE ABSENCE OF ANY DYNAMIC SUPPORT...
EXPECT THE INVRN BASE TO REMAIN NEAR 5K FT. AS POINTED OUT BY THE
DAYSHIFT...LK VORTICES OFTEN DVLP WITH THE FCST LGT LLVL WINDS. BUT
MARGINAL H85 TEMPS ARND -9C WL LIMIT THE INTENSITY OF ANY SHSN THAT
WOULD ACCOMPANY THESE FEATURES...AND THE LGT WINDS WL INHIBIT
BANDING. SO ANY SN ACCUMS SHOULD REMAIN LGT. SINCE THE H85 TEMPS WL
REMAIN MARGINAL FOR LES AND UPSLOPE OMEGA WL REMAIN BLO THE
DGZ...INCLUDED A MENTION OF FZDZ. LINGERING LO CLDS WL LIMIT THE
DIURNAL TEMP FALL. BEST CHC FOR SOMEWHAT LOWER TEMPS WL BE OVER THE
E WITH A RELATIVELY UNMODIFIED/DOWNSLOPE E FLOW OFF ONTARIO THAT
MIGHT ALLOW FOR SOME BREAKS IN THE SC.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 430 AM EST SUN DEC 1 2013
MONDAY THROUGH TUESDAY MORNING...UPPER LEVEL 500MB TROUGHING IS
EXPECTED TO REMAIN IN PLACE ACROSS THE CWA THROUGH THIS TIME PERIOD
AS A WEAK INVERTED RIDGE WEDGES IN ACROSS THE AREA AT THE SURFACE. A
SLIGHTLY DRYER AIRMASS WILL ALSO LINGER THROUGH TUESDAY MORNING
WHICH CAN BE SEEN BY ANALYZING 1000-500MB RH. THE NEXT SURFACE LOW
CAN BE SEEN PUSHING ACROSS THE NORTHERN ROCKIES MONDAY NIGHT AND
EJECTING INTO THE NORTHERN OR CENTRAL PLAINS TUESDAY MORNING AS A
MUCH DEEPER UPPER LEVEL 500MB TROUGH BUILDS IN OVER THE WESTERN U.S.
THERE ARE STILL SOME MODEL DIFFERENCE HOWEVER WITH THE 00Z GFS/NAM
BEING A BIT FASTER AND STRONGER WITH THIS LOW. THE 00Z GFS/NAM
PLACE THE SURFACE LOW ALONG THE NORTH AND SOUTH DAKOTA BORDER BY 12Z
ON TUESDAY. THE 00Z EC/GEM ARE THE SLOWER OF THE SOLUTIONS KEEPING
THE LOW A BIT FARTHER SOUTH AND REMAINING OVER THE CENTRAL PLAINS
JUST A BIT EAST OF THE ROCKIES. EITHER WAY...BOTH SOLUTIONS KEEP THE
PRECIPITATION TO THE WEST OF THE AREA THROUGH THIS TIME PERIOD.
LIGHT EASTERLY WINDS THROUGH MONDAY NIGHT WILL SLOWLY BECOME
SOUTHEASTERLY BY TUESDAY. THIS ALONG WITH H850 TEMPS AROUND -8 TO
-10 C WILL HELP TO KEEP CONDITIONS CLOUDY WITH VERY LIGHT
PRECIPITATION POSSIBLE...MAINLY OVER THE KEWEENAW PENINSULA.
TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...THIS TIME PERIOD REMAINS
UNCERTAIN WHICH HAS BEEN THE CASE OVER THE PAST SEVERAL DAYS...WITH
POOR MODEL AGREEMENT EVEN AS THIS TIME PERIOD IS RAPIDLY
APPROACHING...HOWEVER...THE 00Z EC TENDS TO BE TRENDING A BIT CLOSER
TO THE NAM AND GFS SOLUTIONS. THE GFS/NAM SOLUTIONS BRING INCREASED
MOISTURE AND PRECIPITATION INTO THE CWA BY 18Z TUESDAY...WHILE THE
EC/CANADIAN KEEP THE SYSTEM CENTERED OVER NORTHEASTERN KS DURING
THAT TIME FRAME. THE 00Z GFS PLACES THE SURFACE LOW AND VERTICALLY
STACKED CLOSED UPPER LEVEL 500MB LOW OVER WESTERN WI AT 00Z WED
WHILE THE 00Z EC HAS THE MORE ELONGATED SURFACE LOW OVER CENTRAL
IOWA INTO CENTRAL PLAINS. BY 18Z WED THE 00Z RUN OF THE GFS PUSHES
THE LOW TO THE NORTHEAST OF LAKE SUPERIOR WHILE THE EC IS JUST
PLACING THE SURFACE LOW AND UPPER LEVEL ENERGY INTO THE WESTERN
PORTION OF WI. DEFINITELY EASY TO SEE THAT THERE ARE STILL
SIGNIFICANT DIFFERENCES BETWEEN THESE MODELS...HOWEVER...A BETTER
SIGNAL EXISTS SINCE THE EC IS TRENDING A BIT CLOSES TO THE FASTER
SOLUTIONS...THE BEST IDEA FOR THE TIME BEING WILL BE MORE OF A
MIDDLE OF THE ROAD APPROACH...WITH A SLIGHT LEAN TOWARD THE FASTER
SOLUTIONS. THIS WOULD FAVOR A LATE TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT TIME FRAME FOR THE MORE CONCENTRATED AREA OF PRECIPITATION.
SOUNDINGS FOR THIS TIME PERIOD INDICATE WARMER AIR LIFTING NORTHWARD
ON THE EAST SIDE OF THE LOW HELPING TO TRANSITION THE PRECIPITATION
OVER TO A RAIN SNOW MIXTURE FOR AT LEAST THE EASTERN HALF OF THE
UPPER PENINSULA AS A FAIRLY DEEP WARM LAYER BUILDS IN THROUGH MUCH
OF THE BOUNDARY LAYER. THE FAR WESTERN PORTION OF THE U.P. MAY END
UP SEEING MAINLY SNOW AS SHOWN BY ANALYZING BOTH THE EC AND GFS
PROFILES. IN ANY CASE THIS SYSTEM WILL BE CLOSELY WATCHED OVER THE
NEXT SEVERAL MODEL RUNS TO SEE IF BETTER UPPER AIR SAMPLING CAN
ENTERTAIN GREATER MODEL AGREEMENT.
THURSDAY THROUGH SATURDAY...ATTENTION TURNS TO A POTENTIALLY
PROLONGED PERIOD OF LAKE EFFECT SNOW. MODELS ACTUALLY BECOME IN
BETTER AGREEMENT WITH THE SYSTEM DURING THIS TIME FRAME. EACH OF THE
MODELS SHIFT THE SURFACE LOW NORTHEASTWARD TO NEAR JAMES BY BY 12Z
THURSDAY. AS THIS HAPPENS WINDS WILL SHIFT TO THE WEST ALLOWING LAKE
EFFECT SNOW TO DEVELOP IN AREAS FAVORED BY THAT PARTICULAR WIND
DIRECTION. THURSDAY THROUGH THURSDAY NIGHT THE LAKE EFFECT SNOW WILL
PROBABLY JUST BE STARTING ACROSS THE AREA...BUT SHOULD REMAIN LIGHT.
TRIED TO TREND THE LES CHANCES UPWARD FRIDAY THROUGH SATURDAY AS AN
UPPER LEVEL TROUGH/SHORTWAVE AND INCREASED MOISTURE SHIFTS INTO THE
AREA...ALLOWING FOR ENHANCED LIFT FOR LES TO DEVELOP. ITS STILL A
BIT TOO EARLY TO TELL FOR SURE ABOUT THE OVERALL SNOWFALL
TOTALS...BUT IT DOES LOOK LIKE FRIDAY INTO SATURDAY WILL BE SNOW FOR
WESTERLY WIND FAVORED AREAS OF THE UPPER PENINSULA. AS EARLIER SHIFT
STATED THE SNOW TO LIQUID RATIOS WILL LIKELY BE SLIGHTLY LOWER THAN
USUAL FOR LES AS THE DGZ IS FAIRLY SHALLOW AND FAIRLY LOW IN THE
ATMOSPHERE...WHICH TENDS TO INHIBIT THE MORE FAVORABLE GROWTH RATES
FOR SNOW. STAY TUNED THOUGH AS THIS LES EVENT GETS CLOSER TOWARD THE
WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1208 AM EST SUN DEC 1 2013
COOLER AIR MOVING ACROSS LAKE SUPERIOR BEHIND A LOW PRESSURE SYSTEM
HAS RESULTED IN A MIX OF LIGHT LAKE EFFECT SNOW AND FREEZING DRIZZLE
ACROSS NW AND NCNTRL PORTIONS OF THE FCST AREA THIS EVENING. EXPECTATION
IS THAT THE SNOW/FZDZ WILL CAUSE MVFR TO IFR CONDITIONS AT TAF
SITES OVERNIGHT. A HIGH PRESSURE RIDGE MOVING OVER LAKE SUPERIOR OVERNIGHT
WILL SLOWLY VEER THE WINDS TO THE NORTH-NORTHEAST AND LEAD TO LESS
FAVORABLE WIND DIRECTIONS FOR KCMX/KIWD SO WILL CONTINUE TO SHOW A
DIMINISHING TREND IN SNOW SHOWERS AND RAISE CEILINGS SOMEWHAT BUT
STILL IN MVFR RANGE. CONFIDENCE IN SNOW SHOWER LOCATION/STRENGTH
DIMINISHES LATE TONIGHT INTO SUNDAY...DUE TO WINDS BECOMING LIGHT AND
VARIABLE THROUGH THE DAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 430 AM EST SUN DEC 1 2013
EXPECT NE WINDS UP TO 20 KTS EARLY THIS MORNING TO DIMINISH UNDER
15 KTS AND SLOWLY VEER INTO MON AS A WEAK PRES GRADIENT EXTENDING S
FROM HI PRES MOVING THRU ONTARIO DOMINATES THE UPPER LAKES. STRONGER
E TO SE WINDS UP TO 25 TO PERHAPS 30 KTS WILL THEN DEVELOP INTO MID
WEEK AS THE GRADIENT SHARPENS OVER LAKE SUP BETWEEN THE HI PRES
SHIFTING INTO QUEBEC AND LO PRES MOVING NE FROM THE PLAINS. THERE
WILL BE A SHARP WIND SHIFT TO THE WNW BY THU FOLLOWING THE PASSAGE
OF THE LO TO THE NE. DEPENDING ON THE TRACK AND INTENSITY OF THIS
LO...THERE COULD BE A W GALE ON THU INTO FRI.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KEC
AVIATION...VOSS
MARINE...KC
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1145 PM EST SAT NOV 30 2013
.AVIATION...
//DISCUSSION...
PLENTY OF MID LAYER CLOUD FOR THE OVERNIGHT HOURS. THERE IS AN AREA
OF MVFR CIGS AROUND THE FRONT AND THIS WILL MOVE INTO THE TAF SITES
ON SUNDAY MORNING FOR MBS AND FNT...BUT NOT UNTIL THE AFTERNOON FOR
THE SOUTHERN TAF SITES. ANY PRECIPITATION WITH THE FRONT WILL BE
LIMITED. WILL BRING A FEW HOURS OF LIGHT PRECIPITATION FOR THE
NORTHERN SITES...WITH ONLY MBS HAVING THE POTENTIAL TO HAVE MVFR
VSBY. WITH A LOOK AT THE CURRENT SOUNDING AT DTX AND MODEL
SOUNDINGS... WILL ADD SOME MIXED RAIN AND SNOW.
FOR DTW...DRY AIRMASS PRE COLD FRONT TONIGHT WILL KEEP CLOUDS ABOVE
5000 FT. MVFR CLOUD WILL THEN SETTLE OVER THE TAF SITE DURING SUNDAY
LATE MORNING AND EARLY AFTERNOON IN RESPONSE TO LOW LEVEL COLD AIR
ADVECTION.
//DTW THRESHOLD THREATS...
* LOW CONFIDENCE IN CEILING HEIGHTS BELOW 5000 FT PRIOR TO 15Z
SUNDAY. HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET SUNDAY AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 916 PM EST SAT NOV 30 2013
UPDATE...
CURRENT CONDITIONS ARE CERTAINLY SUPPORTIVE OF FOLLOWING THE
PREVIOUS FORECASTS THOUGHTS ON LOWER CHANCES OF PRECIPITATION THAN
WHAT THE 12Z AND 18Z MODELS ARE SUGGESTING. NEARLY ALL OF THE
RADAR RETURNS OVER LOWER MICHIGAN ARE VIRGA. LATEST RUC RUNS ARE
MORE SUPPORTIVE OF A DRIER OVERNIGHT AND ARE REALLY IN LINE WITH
THE CURRENT FORECAST POPS...CLOUDS AND QPF. 00Z SOUNDINGS AND THE
LATEST RUC SOUNDINGS SUGGEST THAT IT WILL TAKE SOME TIME TO
SATURATE THE LAYER BETWEEN 3K AND 6K FEET. WHILE THERE IS SOME
MOISTURE ALONG THE FRONT BELOW 3K FEET...IT IS REALLY ABOVE THIS
THAT DRY AIR REMAINS IN PLACE TO LIMIT PRECIP. THE OTHER ITEM THAT
SHOWS WELL IN THE SOUNDINGS IS THAT THE FREEZING LEVEL WILL LIKELY
BE 1000 TO 2000 FEET ABOVE THE SURFACE WHEN WE FIRST SATURATE. ANY
PRECIP THAT HAS FALLEN ACROSS NRN LOWER THIS EVENING HAS BEEN
RAIN. THEREFORE WILL BRING IN A MIX OF RAIN...AT LEAST AT THE
START...FOR ANY PLACE THE DOES GET SOME PRECIP OVERNIGHT.
WILL RAISE TEMPS JUST A BIT OVERNIGHT DUE TO THE COMBINATION OF
THE CLOUDS AND SOUTHERLY WIND AHEAD OF THE COLD FRONT. TEMPS WILL
EVENTUALLY REACH THEIR FORECAST LOWS WITH THE FRONTAL PASSAGE OR
WITH THE EVAPORATE COOLING. THE EXCEPTION WILL BE IN THE FAR
SOUTH OF THE FORECAST AREA WHERE MOSTLY CLEAR SKIES ARE ALLOWING
TEMPS TO FALL.
PREV DISCUSSION...ISSUED 319 PM EST SAT NOV 30 2013
SHORT TERM...TONIGHT
A THERMAL WAVE DIGGING SOUTHEASTWARD ALONG THE TRAILING EDGE OF NE
NORTH AMERICAN UPPER LEVEL TROUGH WILL BE THE WEATHER AFFECTING THE
CENTRAL GREAT LAKES TONIGHT. THE CYCLONIC VORTICITY ENERGY
ASSOCIATED WITH THE SHORT WAVELENGTH THERMAL RIDGE IS FRAGMENTED
WITH THE INITIAL SHORTWAVE DAMPENING WHILE IT PUSHES EAST OF LAKE
SUPERIOR THIS AFTERNOON. A SECOND SHORTWAVE IS NOW SLIDING THROUGH
THE MINNESOTA ARROWHEAD AND INTO THE FAR WESTERN LAKE SUPERIOR BASIN
TAKING OVER WITH TIME. THIS SHORTWAVE WILL PROVIDE A NECESSARY
FORCING COMPONENT AFTER 9Z OVER THE FAR NORTHERN CWA WHICH SHOULD
FINALLY ALLOW PRECIPITATION TO FALL. OTHERWISE THE MIX OF DYNAMICS
SUPPORTIVE OF ASCENT IS LIMITED. ANALYSIS OF 285K SYSTEM RELATIVE
ISENTROPIC ASCENT IS VERY UNINSPIRING DESPITE SOME LINKAGE OF RIGHT
ENTRANCE REGION DYNAMICS ALOFT WITH 850-700MB DEFORMATION. THE
DEFORMATION IS MODELED TO BE ASSOCIATED WITH THE CONVERGENCE FEATURE
OF THE FRONT. EXPECT THIS FORCING TO STRIPE FOR A VERY LIMITED TIME
FROM WEST TO EAST NORTHEAST...PRIMARILY ACROSS THE FAR NORTHERN
COUNTIES. WET BULB AND OFFERED BUFKIT SOUNDINGS SUPPORT AN ALL SNOW
EVENT...TRENDED TO ALL SNOWFLAKES. A DUSTING WILL BE POSSIBLE NORTH
AFTER 8Z...PERHAPS A HALF TO 1 INCH IN THE NORTHERN THUMB.
LONG TERM...SUNDAY THROUGH NEXT SATURDAY
MID LEVEL ENERGY IS FORECAST TO RAPIDLY SHEER TO THE EAST OF THE
AREA LATE SUNDAY MORNING. THE 12Z MODEL SUITE ALL SUGGEST THE
ASSOCIATED MID LEVEL ASCENT WILL RESIDE ALONG THE 1-69 CORRIDOR INTO
THE THUMB REGION BY 12Z BEFORE QUICKLY WANING BY NOON. BOTH NAM AND
GFS APPEAR TOO AGRESSIVE IN MOISTENING THE LOW LEVELS...SUGGESTING
THAT WET BULB COOLING MAY BE STRONG ENOUGH TO KEEP ANY LINGERING
MORNING PRECIP AS LIGHT SNOW. UPSTREAM OBSERVATIONS DO HOWEVER
SUPPORT MODEL SOLUTIONS WHICH BRING A POST FRONTAL LOW STRATUS DECK
INTO THE AREA FOLLOWING THE PASSAGE OF A WEAK SURFACE COLD FRONT.
THESE LOW CLOUDS ARE EXPECTED TO ENVELOPE THE TRI CITIES AND THUMB
BY DAYBREAK...THEN OVERSPREAD METRO DETROIT EARLY SUN AFTERNOON.
OVERALL WEAK POST FRONTAL COLD AIR ADVECTION WILL SUPPORT SUN MAX
TEMPS IN THE MID/UPPER 30S ACROSS THE NORTH AND LOW 40S SOUTH OF THE
I-96/696 CORRIDOR.
THE DEPTH OF THE POST FRONTAL COLD AIR SUN AFTERNOON WILL BE GREATER
OVER LAKE HURON...WHICH WILL RESULT IN A DEEPENING CONVECTIVE DEPTH
OVER THE LAKE. MODEL SOLUTIONS SUGGEST A GOOD RESPONSE OFF THE
LAKE...ENOUGH TO SUPPORT A CHANCE OF SNOW SHOWERS OVER THE THUMB SUN
AFTERNOON INTO SUNDAY EVENING AS THE FLOW TURNS TOWARD THE NE. THE
EXPECTED DEGREE OF VARIABILITY IN THE LOW LEVEL WIND DIRECTION DOES
NOT SUPPORT A PROLONGED CONVERGENT BAND...SO FORECAST ACCUMS WILL BE
KEPT MINIMAL. MID LEVEL SUBSIDENCE WILL LOWER INVERSION HEIGHTS SUN
NIGHT AND WILL MAINTAIN THE LOW STRATUS OVER THE REGION. CONTINUED
LOW LEVEL MOISTURE FLUX UNDER THE NE FLOW MAY HOWEVER SUPPORT SOME
DRIZZLE SUN NIGHT INTO MON MORNING OVER A GOOD PORTION OF SE MI.
CONFIDENCE IS NOT QUITE HIGH ENOUGH TO ADD DRIZZLE TO THE
ZONE/GRIDS AT THIS POINT...BUT IS SOMETHING LATER SHIFTS WILL
HAVE TO MONITOR. AMPLE LOW CLOUDS AND WEAK LOW LEVEL THERMAL
ADVECTION IS LIKELY TO HOLD TEMPS IN THE 30S SUN NIGHT INTO MON
MORNING.
A LOW AMPLITUDE MID LEVEL TROUGH IS FORECAST TO TRAVERSE THE OHIO
VALLEY ON MONDAY. DESPITE THE OVERALL WEAK FORCING WITH THIS
FEATURE...MODEL SOLUTIONS DO SUGGEST A HEALTHY SURGE OF MID LEVEL
MOISTURE INTO SRN MI. THIS COUPLED WITH THE EXPECTED STRATUS AND
WEAK LARGE SCALE ASCENT MAY BE ABLE TO GENERATE A FEW LIGHT SNOW
AND/OR RAIN SHOWERS.
SOUTHEAST MICHIGAN CONTINUES TO BE ON A ROLLER COASTER AS FAR AS
TEMPERATURES ARE CONCERNED WITH TEMPS WARMING THROUGH THURSDAY
BEFORE COOLING OFF BY THE WEEKEND. UPPER LEVEL RIDGE WILL WORK INTO
THE AREA TUESDAY HELPING TO KEEP THINGS ON THE DRIER SIDE. PRECIP
CHANCES START TO INCREASE WEDNESDAY AS A LOW TRAVERSES OVER THE
NORTHERN GREAT LAKES. SOUTHERLY FLOW OUT AHEAD OF THIS SYSTEM WILL
HELP TO BRING IN MOISTURE AND WARMER AIR. PRECIP TYPE WILL LIKELY
START OFF AS SNOW BEFORE QUICKLY TRANSITIONING TO ALL RAIN AS
WARMER TEMPS OVERSPREAD THE AREA. BETTER CHANCE FOR MEASURABLE
PRECIP WILL COME THURSDAY INTO FRIDAY AS ANOTHER LOW DEVELOPS AND
MOVES TOWARDS THE GREAT LAKES. CURRENTLY THIS LOW LOOKS TO TRACK
SOUTH OF MICHIGAN WHICH WOULD PUT THE CWA IN THE COLD SECTOR WITH
SNOW BEING THE MAIN PRECIP TYPE. COOLER TEMPS MAKE A RETURN NEXT
WEEKEND AS WESTERLY FLOW INCREASES OVER SOUTHEAST MICHIGAN.
MARINE...
THE SOUTHERLY WINDS WILL DIMINISH DURING THE COURSE OF THE EVENING
AS THE GRADIENT RELAXES. THIS WILL OCCUR AS A WEAK AREA OF LOW
PRESSURE EXPANDS ACROSS LAKE HURON TONIGHT. THIS LOW WILL ADVANCE
INTO ONTARIO ON SUNDAY WHICH WILL CAUSE THE WINDS TO TURN
NORTHEASTERLY OVER LAKE HURON. WIND SPEEDS WILL INCREASE DURING THE
AFTERNOON. GUSTS SHOULD REMAIN AT OR BELOW 25 KNOTS. THE GRADIENT
WILL THEN RELAX BY MONDAY. WEAK HIGH PRESSURE WILL RESULT IN LIGHT
WINDS INTO WEDNESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....JVC
UPDATE.......JVC
SHORT TERM...CB
LONG TERM....SC/SS
MARINE.......SC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1148 AM CST Sun Dec 1 2013
.SHORT TERM: (Through Late This Afternoon)
Issued at 335 AM CST Sun Dec 1 2013
Think the challenge for today will be forecasting cloud cover. A
stratus deck between 4000-5000ft is moving across he eastern Ozarks
and parts of Southern Illinois this morning. Think this area of
stratus will continue advecting eastward faster than the western
edge will erode as has been the case for the past few hours.
Therefore there should be substantial cloud cover over southeast
Missouri and parts of southern Illinois this morning. The 00Z NAM
eventually cleared it out and this matches well with satellite
trends at this time; however the RAP backbuilds the cloud cover, as
does the 06Z NAM and this suggests that areas generally southeast of
a line from Vichy, MO to Salem, IL may not see much sun today. Am
sticking closer to the less cloudy solution at this time, but this
may ultimately prove to be too optimistic.
Temperatures may be challenging as well. Can`t seem to forecast
warm enough the past couple of days. Missed highs both Friday and
Saturday by to to three degrees. Lingering cloud cover over the
eastern Ozarks and southwest Illinois may make this especially
challenging. For highs today, used a blend of 925 mix-down
temperatures and MOS. Tweaked southern zones down a couple of
degrees from that to account for cloud cover, and the rest of the
area up a degree or two to try to compensate for my apparent cool
bias.
Britt
.LONG TERM: (Tonight through Saturday)
Issued at 335 AM CST Sun Dec 1 2013
(Tonight - Tuesday)
Have not made too many changes to going forecast during this
period. Low level moisture progs suggest that stratus will
redevelop this evening, particularly over the southern and
eastern part of the CWA. Have kept chance of light drizzle in
these areas where this moisture will be the deepest and there will
be some very light ascent. As we go into Monday, GFS/NAM/ECMWF all
show a weak shortwave trough racing into the area from the west,
though it is not as deep as was forecast 24 hours ago. Have left
chance of sprinkles in for tomorrow morning as the trough axis
will move through the area by midday.
Temperatures will begin to warm up ahead ahead of the next storm
system. Expect temperatures to climb into the 50s on Monday with
some spots reaching 60 on Tuesday.
(Wednesday - Saturday)
Main concern continues to be the potential for a wintry precipitation
and the big cool down mid to late week. There still ia a great
deal of uncertainty regarding timing, precipitation types and
amounts. While the GFS is still the fastest with the passage of
the cold front, the 00Z ECMWF now brings the cold front through
the area during the day on Wednesday instead of Wednesday Night.
The cold front will have moved to the south of the area
Wednesday. Best forcing for precipitation will hinge on mid-level
frontogenesis and shortwave troughs moving through fast west-
southwesterly flow aloft. Have likely pops on Thursday and
Thursday Night over southeastern half of the CWA with the chance
continuing into Friday. Will continue to have a simple mix of rain
and snow because of the uncertainty for now, but thermal profiles
from forecast soundings certainly suggest the potential for sleet
or freezing rain over the southern half of the CWA. 850mb
temperatures by next Friday and Saturday will be in the -10 to
-12C range supporting highs only in the 20s with lows in the
single digits and teens.
Britt
&&
.AVIATION: (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1050 AM CST Sun Dec 1 2013
Very weak cold front has just pushed se of CPS late this mrng.
Only expect light nely sfc winds at UIN and COU this aftn, and
nwly in the St Louis metro area veering around to a nely direction
by early evng. The sfc wind will remain light tgt and continue to
veer around to an e-sely direction by late tgt as the sfc ridge
over the nrn Plains moves ewd through the Great Lakes region. The
sfc wind will strengthen some from a sely direction Monday mrng.
Mid-high level clouds will advect into the region tgt. It appears
that there will be patchy fog and stratus clouds redeveloping late
tgt. The best potential for stratus clouds may be south of the taf
sites, but there will likely be at least light fog impacting the
COU and St Louis areas and possibly also UIN as well.
Specifics for KSTL: Light nwly sfc wind this aftn will gradually
veer around to a nely direction by this evng, e-sely direction by
late tgt, then strengthen to 7-9 kts from a s-sely direction Monday
aftn. Mid-high level cloudiness will advect into STL by late tgt.
May also have some light fog late tgt/early Monday mrng as well as
patchy stratus clouds mainly Monday mrng.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
555 AM CST Sun Dec 1 2013
.SHORT TERM: (Through Late This Afternoon)
Issued at 335 AM CST Sun Dec 1 2013
Think the challenge for today will be forecasting cloud cover. A
stratus deck between 4000-5000ft is moving across he eastern Ozarks
and parts of Southern Illinois this morning. Think this area of
stratus will continue advecting eastward faster than the western
edge will erode as has been the case for the past few hours.
Therefore there should be substantial cloud cover over southeast
Missouri and parts of southern Illinois this morning. The 00Z NAM
eventually cleared it out and this matches well with satellite
trends at this time; however the RAP backbuilds the cloud cover, as
does the 06Z NAM and this suggests that areas generally southeast of
a line from Vichy, MO to Salem, IL may not see much sun today. Am
sticking closer to the less cloudy solution at this time, but this
may ultimately prove to be too optimistic.
Temperatures may be challenging as well. Can`t seem to forecast
warm enough the past couple of days. Missed highs both Friday and
Saturday by to to three degrees. Lingering cloud cover over the
eastern Ozarks and southwest Illinois may make this especially
challenging. For highs today, used a blend of 925 mix-down
temperatures and MOS. Tweaked southern zones down a couple of
degrees from that to account for cloud cover, and the rest of the
area up a degree or two to try to compensate for my apparent cool
bias.
Britt
.LONG TERM: (Tonight through Saturday)
Issued at 335 AM CST Sun Dec 1 2013
(Tonight - Tuesday)
Have not made too many changes to going forecast during this
period. Low level moisture progs suggest that stratus will
redevelop this evening, particularly over the southern and
eastern part of the CWA. Have kept chance of light drizzle in
these areas where this moisture will be the deepest and there will
be some very light ascent. As we go into Monday, GFS/NAM/ECMWF all
show a weak shortwave trough racing into the area from the west,
though it is not as deep as was forecast 24 hours ago. Have left
chance of sprinkles in for tomorrow morning as the trough axis
will move through the area by midday.
Temperatures will begin to warm up ahead ahead of the next storm
system. Expect temperatures to climb into the 50s on Monday with
some spots reaching 60 on Tuesday.
(Wednesday - Saturday)
Main concern continues to be the potential for a wintry precipitation
and the big cool down mid to late week. There still ia a great
deal of uncertainty regarding timing, precipitation types and
amounts. While the GFS is still the fastest with the passage of
the cold front, the 00Z ECMWF now brings the cold front through
the area during the day on Wednesday instead of Wednesday Night.
The cold front will have moved to the south of the area
Wednesday. Best forcing for precipitation will hinge on mid-level
frontogenesis and shortwave troughs moving through fast west-
southwesterly flow aloft. Have likely pops on Thursday and
Thursday Night over southeastern half of the CWA with the chance
continuing into Friday. Will continue to have a simple mix of rain
and snow because of the uncertainty for now, but thermal profiles
from forecast soundings certainly suggest the potential for sleet
or freezing rain over the southern half of the CWA. 850mb
temperatures by next Friday and Saturday will be in the -10 to
-12C range supporting highs only in the 20s with lows in the
single digits and teens.
Britt
&&
.AVIATION: (For the 12z TAFs through 12z Monday Morning)
Issued at 541 AM CST Sun Dec 1 2013
Primary concern this morning is an area of fog over central
Missouri where VSBYS AOB 1SM are being reported. Expect this fog
to lift and dissipate after 14Z this morning. Some patchy fog
with VSBYS between 2-5SM have been reported further east this
morning as well, however the lower VSBYS have been intermittent.
At any rate, expect VFR flight conditions to prevail after 15-16Z
this morning. Am concerned that fog will again be an issue tonight
after 06Z. Not sure yet how low to go, so started out with MVFR
conditions, but will not be surprised to see lower VSBYS by 12Z
Monday morning. Winds will be variable through 12Z Monday as a
weak cold front becomes nearly stationary over the area, and then
begins to drift back to the north late in the period.
Specifics for KSTL:
Expect VFR flight conditions to prevail at Lambert at least
through 06Z tonight. Guidance is hinting that there could be some
MVFR VSBYS in fog after 06Z tonight, and I have lowered VSBYS in
the other STL Metro TAFs; however it`s tough to get fog at Lambert
due to the metro heat island so have left mention of fog out for
now. Winds will be pretty wishy-washy over the next 24 hours as a
weak cold front becomes nearly stationary over the area, but the
wind will pick up from the south after 12Z Monday as the front
moves back to the north.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
339 AM CST Sun Dec 1 2013
.SHORT TERM: (Through Late This Afternoon)
Issued at 335 AM CST Sun Dec 1 2013
Think the challenge for today will be forecasting cloud cover. A
stratus deck between 4000-5000ft is moving across he eastern Ozarks
and parts of Southern Illinois this morning. Think this area of
stratus will continue advecting eastward faster than the western
edge will erode as has been the case for the past few hours.
Therefore there should be substantial cloud cover over southeast
Missouri and parts of southern Illinois this morning. The 00Z NAM
eventually cleared it out and this matches well with satellite
trends at this time; however the RAP backbuilds the cloud cover, as
does the 06Z NAM and this suggests that areas generally southeast of
a line from Vichy, MO to Salem, IL may not see much sun today. Am
sticking closer to the less cloudy solution at this time, but this
may ultimately prove to be too optimistic.
Temperatures may be challenging as well. Can`t seem to forecast
warm enough the past couple of days. Missed highs both Friday and
Saturday by to to three degrees. Lingering cloud cover over the
eastern Ozarks and southwest Illinois may make this especially
challenging. For highs today, used a blend of 925 mix-down
temperatures and MOS. Tweaked southern zones down a couple of
degrees from that to account for cloud cover, and the rest of the
area up a degree or two to try to compensate for my apparent cool
bias.
Britt
.LONG TERM: (Tonight through Saturday)
Issued at 335 AM CST Sun Dec 1 2013
(Tonight - Tuesday)
Have not made too many changes to going forecast during this
period. Low level moisture progs suggest that stratus will
redevelop this evening, particularly over the southern and
eastern part of the CWA. Have kept chance of light drizzle in
these areas where this moisture will be the deepest and there will
be some very light ascent. As we go into Monday, GFS/NAM/ECMWF all
show a weak shortwave trough racing into the area from the west,
though it is not as deep as was forecast 24 hours ago. Have left
chance of sprinkles in for tomorrow morning as the trough axis
will move through the area by midday.
Temperatures will begin to warm up ahead ahead of the next storm
system. Expect temperatures to climb into the 50s on Monday with
some spots reaching 60 on Tuesday.
(Wednesday - Saturday)
Main concern continues to be the potential for a wintry precipitation
and the big cool down mid to late week. There still ia a great
deal of uncertainty regarding timing, precipitation types and
amounts. While the GFS is still the fastest with the passage of
the cold front, the 00Z ECMWF now brings the cold front through
the area during the day on Wednesday instead of Wednesday Night.
The cold front will have moved to the south of the area
Wednesday. Best forcing for precipitation will hinge on mid-level
frontogenesis and shortwave troughs moving through fast west-
southwesterly flow aloft. Have likely pops on Thursday and
Thursday Night over southeastern half of the CWA with the chance
continuing into Friday. Will continue to have a simple mix of rain
and snow because of the uncertainty for now, but thermal profiles
from forecast soundings certainly suggest the potential for sleet
or freezing rain over the southern half of the CWA. 850mb
temperatures by next Friday and Saturday will be in the -10 to
-12C range supporting highs only in the 20s with lows in the
single digits and teens.
Britt
&&
.AVIATION: (For the 06z TAFs through 06z Sunday Night)
Issued at 1133 PM CST Sat Nov 30 2013
Weak surface frontal boundary extending from central Michigan
through far northwest Illinois and then becoming stationary over
northern Kansas. Front is expected to move southeast and move
through UIN-COU areas between 0900 and 1100 UTC and through STL
area after 1400 UTC. Scattered to broken area of clouds will move
through the southern half of Missouri from 0600 - 1100 UTC.
Scattered area of clouds will be east of COU and south of UIN
areas. Surface winds will shift from WSW to NW direction after
passage of front. Wind speeds will range from 4 to 7 kts.
Specifics for KSTL: Scattered to broken layer of clouds at 040
will move through STL area between 0600 and 0900 UTC. Surface
winds will be light southwest then shift to West-northwest
direction around 5 kts after 1400 UTC. Clouds will remain
scattered 040 with higher broken deck aob 200. Surface winds will
shift to north-northwest by early afternoon with speeds o0f 4 to 6
kts.
Przybylinski
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
325 PM MST SUN DEC 1 2013
.DISCUSSION...
MAIN FORECAST CHALLENGE IN THE SHORT-TERM CONTINUES TO BE NAILING
DOWN WHEN THE PERSISTENT LOW CLOUD DECK OVER NW AND WEST CENTRAL NM
WILL SCOUR OUT OF THE AREA. THE VAST MAJORITY OF MODEL GUIDANCE DID
NOT SHOW THESE CLOUDS CONTINUING TO PLAGUE THE AREA TODAY BUT ALAS
THEY ARE STILL HOLDING STRONG. THE RUC13 WAS THE BEST TO HOLD ONTO
SATURATION IN THE NEAR SURFACE LAYER AND INDICATIONS ARE THAT IT
WILL CONTINUE TONIGHT AND EARLY MONDAY. WINDS ALOFT AND EVEN AT THE
SURFACE ARE INCREASING HOWEVER IT IS POSSIBLE THE THICK/PERSISTENT
LOW CLOUD DECK IS FEEDING BACK TO STRENGTHEN LOW LEVEL INVERSIONS
AND KEEP A VERY SHALLOW BOUNDARY LAYER DECOUPLED. OTHER INTERESTING
ITEM WILL BE WHETHER LOW CLOUDS CAN SEEP OVER THE WEST MESA AND END
UP IN THE MIDDLE RIO GRANDE VALLEY TONIGHT AS INCREASING NW FLOW
ADVECTS THE LAYER SE. BEST SHOT WILL BE WEST SIDE SO HAVE INCREASED
TO MOSTLY CLOUDY THERE OVERNIGHT.
CONSIDERABLE DIFFERENCES REMAIN WITH MODEL GUIDANCE ON THE DETAILS
OF THE NEXT SIGNIFICANT STORM SYSTEM BEYOND WEDNESDAY. FIRST WE
HAVE TO DEAL WITH SOME WIND. NW FLOW OVER THE REGION TODAY WILL
BACK TO WEST AND INCREASE TUESDAY. 700-500MB LAYER WINDS BTWN 50
AND 60KTS WILL COMBINE WITH A SURFACE LOW OVER THE PLAINS TO CREATE
STRONG WEST WINDS ALONG AND EAST OF THE CENTRAL MT CHAIN. IT IS
STILL A LITTLE EARLY BUT BETS ARE GOOD ON A HIGH WIND WATCH FROM
THE FOLLOWING SHIFT FOR TUESDAY. HEIGHT FALLS AND COLD ADVECTION
WILL BEGIN TUESDAY NIGHT ACROSS THE WEST AS THE JET AXIS DEPARTS
TO THE EAST. MEANWHILE...THE PLAINS PORTION OF AN ARCTIC AIRMASS
WILL BE SHIFTING SOUTH TOWARD THE NE PLAINS.
MODELS THEN STRUGGLE CONSIDERABLY DEALING WITH THE APPROACH OF A
SHEARING UPPER TROUGH AXIS OVER THE WESTERN CONUS WEDNESDAY AND
THURSDAY AND THE DEGREE OF MOISTURE ASSOCIATED WITH IT. A REALLY
GOOD CERTAINTY IS THAT IT IS GOING TO GET VERY COLD. AT THIS TIME
THE SUITE OF ENSEMBLE AND WPC GUIDANCE SHOWS THE PLAINS PORTION OF
THE ARCTIC AIRMASS SETTLING ONTO THE EAST SLOPES OF THE CENTRAL MT
CHAIN WHILE THE SECOND PORTION SHIFTS SOUTH THRU THE INTERMOUNTAIN
WEST. 700MB TEMPS BTWN -10 AND -14C WITH THIS AIRMASS ARE 1 TO 2
STANDARD DEVIATIONS BELOW CLIMO AND RESULTS IN HIGH TEMPS 15 TO 25
F BELOW NORMAL ALL AREAS. QPF AND SNOW IMPACTS WILL BE THE GREATEST
CHALLENGE WITH THIS SYSTEM. MODELS AGREE A BAND OF SNOW WILL SHIFT
SE OVER WESTERN NM WEDNESDAY THEN DISSIPATES WEDNESDAY NIGHT...WHILE
LOW CLOUDS AND LIGHT SNOW OR FLURRIES IMPACT THE EAST. THE GFS IS
THEN THE MOST BULLISH BREAKING OUT A LARGE AREA OF LIGHT/MODERATE
SNOW ALONG AND EAST OF THE CONT DVD THURSDAY THEN TAPERS OFF INTO
THE EAST FRIDAY. AT THIS TIME IMPACTS TO TRAVEL MAY BE HIGH WITH
EVEN LIGHT AMOUNTS OF PRECIP DUE TO THE SEVERITY OF THE COLD AND
BLOWING SNOW.
BELIEVE OR NOT MODELS ARE ADVERTISING AN EVEN COLDER SECOND ARCTIC
AIRMASS TO SHIFT SOUTH OVER THE WESTERN CONUS MONDAY AND TUESDAY OF
NEXT WEEK. 700MB TEMPS OVER NORTHERN NM ARE ADVERTISED BY THE ECMWF
TO FALL TO -24C WHICH IS EXCEPTIONALLY COLD. ANOTHER ROUND OF SNOW
IS ALSO ADVERTISED.
GUYER
&&
.FIRE WEATHER...
MAIN FIRE WEATHER ISSUES NEXT FEW DAYS WILL BE THE STRONG INVERSIONS
IN PLACE ACROSS ROUGHLY THE NW QUARTER TO THIRD OF THE STATE...
EMPHASIZING THE NW AND WEST CENTRAL VALLEYS TO THE WEST OF THE
CONTINENTAL DIVIDE. THIS WILL CONTINUE QUITE STRONG THROUGH TONIGHT
AND MON MORN...IMPROVING SOME MON AFTN AND RETURNING MORE WEAKLY MON
NIGHT INTO TUE MORN. AS A RESULT VENTILATION RATES TO REMAIN MAINLY
POOR IN THIS AREA THROUGH MON NIGHT. ACCOMPANYING THIS WILL BE VERY
LOW CLOUD DECK AND FREEZING FOG TONIGHT AND WELL INTO MON MORN.
OTHER SIGNIFICANT FIRE WX CONCERN WILL BE RISK OF MARGINALLY
CRITICAL FIRE WEATHER CONDITIONS FOR PERHAPS 2 OR 3 HOURS TUE AFTN
IN MAINLY SOUTHERN PORTION OF ZONE 108 IN EAST CENTRAL NM. MAIN
LIMITING ISSUE WILL BE THE MINIMUM RH.
OUTSIDE OF THE ABOVE MENTIONED AREAS...OVERNIGHT HUMIDITY RECOVERY
WILL STILL BE VERY GOOD TO EXCELLENT IN THE ESTANCIA AND UPPER RIO
GRANDE VALLEYS. HOWEVER...RECOVERIES WILL NOT BE AS HIGH IN THE
EASTERN PLAINS...MAINLY 45 TO 55 PERCENT. SCATTERED LOCALES ALONG
THE CENTRAL MOUNTAIN CHAIN AND CENTRAL HIGHLANDS WILL EXPERIENCE
BREEZY TO OCCASIONALLY WINDY CONDITIONS THROUGHOUT THE NIGHT AND
INTO MON. STILL...POOR VENTILATION/DISPERSION IS EXPECTED WEST OF
CENTRAL MTN CHAIN THROUGH MON NIGHT WITH TEMPERATURES RISING A
COUPLE TO SEVERAL DEGREES OVER TODAY. EAST OF CENTRAL MTN CHAIN
EXPECT FAIR TO LOCALLY VERY GOOD VENT RATES MON AFTN.
FLOW ALOFT BECOMES MORE WESTERLY MON NIGHT AND WEST SOUTHWESTERLY
BY TUE NIGHT AS LONGWAVE TROUGH ESTABLISHES TO THE WEST OF NM. AS
WINDS DRAMATICALLY INCREASE ALOFT THE 10000 FT LEVEL WINDS ARE
LIKELY TO REACH 45 TO 65 KT...PERHAPS EVEN A BIT HIGHER...ON MUCH OF
THE HIGHER TERRAIN. STRONG BUT RATHER SHALLOW BACK DOOR FRONT LIKELY
TO ENTER FAR NE NM LATE TUE OR EARLY WED WITH THE USUAL TIMING
DIFFERENCES BETWEEN THE MODELS. STRONG WINDS WILL REMAIN A CONCERN
FOR HIGH TERRAIN AREAS TUE. AHEAD OF THE FRONT THE EASTERN PLAINS
WOULD GET SOME DOWNSLOPING WARMING EFFECTS...AS TEMPS RUN 8 TO 15
DEGREES ABOVE AVERAGE WITH HUMIDITY OF 15 TO 20 PERCENT TUE AFTN.
BREEZY TO WINDY CONDITIONS WILL LIKELY PERSIST INTO WED...ESPECIALLY
THE HIGH TERRAIN ZONES...WHILE MUCH COLDER AIR SPILLS INTO THE STATE
FROM THE NE AND NW. SOME LIGHT TO LOCALLY MODERATE PRECIPITATION
WILL ALSO BE POSSIBLE ACROSS FCST AREA WED...SPREADING FARTHER EAST
THU AND FRI. PREFERRED AREAS WILL BE NW TWO THIRDS OF THE STATE. BY
THU THE ENTIRE FORECAST AREA TEMPS LIKELY TO FALL TO BETWEEN 10 AND
30 DEGREES BELOW AVERAGE. LITTLE IF ANY MODERATION FROM THE WELL
BELOW NORMAL TEMPS FRI. VENTILATION WILL SEE A MAJOR BOOST TUE AND
WED...BUT THEN STEADILY LOWER THU INTO FRI.
43
&&
.AVIATION...
18Z TAF CYCLE
LOW CLOUDS AND FOG HANGING VERY TOUGH OVER NORTHWEST AND WEST
CENTRAL NM. UPDATED SKY COVER TO KEEP LOW CLOUDS OVER THE AREA
DESPITE MOST MODEL GUIDANCE SCOURING OUT CLOUD COVER. LATEST
VISIBLE SATELLITE IMAGERY SHOWS AREA ACTUALLY EXPANDING SLIGHTLY.
ALSO NEEDED TO LOWER MAX TEMPS QUITE A BIT ACROSS THIS AREA AS
VERY LITTLE WARMING IS NOW EXPECTED. LOW CLOUDS MAY EVEN STAY
IN PLACE TONIGHT SINCE THE AREA IS LIKELY PROVIDING A FEEDBACK
TO VERY STRONG INVERSIONS IN PLACE. BY MONDAY ATMOSPHERIC WINDS
AND THE SURFACE PRESSURE GRADIENT BEGIN INCREASING AHEAD OF A
STRONG PACIFIC FRONT FOR LATE TUESDAY/WEDNESDAY.
43
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 28 44 28 50 / 0 0 0 0
DULCE........................... 20 47 21 44 / 0 0 0 10
CUBA............................ 25 50 25 49 / 0 0 0 0
GALLUP.......................... 24 52 24 50 / 0 0 0 0
EL MORRO........................ 23 51 24 48 / 0 0 0 0
GRANTS.......................... 23 54 24 52 / 0 0 0 0
QUEMADO......................... 26 55 27 54 / 0 0 0 0
GLENWOOD........................ 30 64 29 59 / 0 0 0 0
CHAMA........................... 17 44 19 37 / 0 0 0 20
LOS ALAMOS...................... 27 49 28 47 / 0 0 0 0
PECOS........................... 31 49 30 44 / 0 0 0 0
CERRO/QUESTA.................... 7 42 11 38 / 0 0 0 0
RED RIVER....................... 16 40 18 35 / 0 0 5 0
ANGEL FIRE...................... 23 42 24 38 / 0 0 0 0
TAOS............................ 12 45 16 43 / 0 0 0 0
MORA............................ 27 51 28 47 / 0 0 0 0
ESPANOLA........................ 24 51 26 50 / 0 0 0 0
SANTA FE........................ 27 48 27 45 / 0 0 0 0
SANTA FE AIRPORT................ 27 52 27 50 / 0 0 0 0
ALBUQUERQUE FOOTHILLS........... 33 55 33 56 / 0 0 0 0
ALBUQUERQUE HEIGHTS............. 33 57 34 57 / 0 0 0 0
ALBUQUERQUE VALLEY.............. 31 58 30 59 / 0 0 0 0
ALBUQUERQUE WEST MESA........... 31 58 32 59 / 0 0 0 0
LOS LUNAS....................... 30 58 29 61 / 0 0 0 0
RIO RANCHO...................... 31 57 32 58 / 0 0 0 0
SOCORRO......................... 33 61 33 65 / 0 0 0 0
SANDIA PARK/CEDAR CREST......... 31 52 32 53 / 0 0 0 0
TIJERAS......................... 32 54 33 54 / 0 0 0 0
MORIARTY/ESTANCIA............... 25 50 27 49 / 0 0 0 0
CLINES CORNERS.................. 31 51 32 50 / 0 0 0 0
GRAN QUIVIRA.................... 34 53 33 54 / 0 0 0 0
CARRIZOZO....................... 34 59 33 58 / 0 0 0 0
RUIDOSO......................... 39 60 39 57 / 0 0 0 0
CAPULIN......................... 30 58 31 51 / 0 0 0 0
RATON........................... 28 60 29 54 / 0 0 0 0
SPRINGER........................ 27 62 28 56 / 0 0 0 0
LAS VEGAS....................... 30 60 31 51 / 0 0 0 0
CLAYTON......................... 35 66 36 56 / 0 0 0 0
ROY............................. 34 65 35 59 / 0 0 0 0
CONCHAS......................... 37 67 37 63 / 0 0 0 0
SANTA ROSA...................... 40 66 40 64 / 0 0 0 0
TUCUMCARI....................... 37 69 38 68 / 0 0 0 0
CLOVIS.......................... 39 66 40 67 / 0 0 0 0
PORTALES........................ 41 68 41 68 / 0 0 0 0
FORT SUMNER..................... 42 68 42 69 / 0 0 0 0
ROSWELL......................... 42 74 42 77 / 0 0 0 0
PICACHO......................... 42 70 42 67 / 0 0 0 0
ELK............................. 42 67 42 62 / 0 0 0 0
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
708 PM EST MON DEC 2 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES WILL SHIFT INTO
SOUTHERN QUEBEC INTO TUESDAY...PROVIDING LIGHT PRECIPITATION TO MUCH
OF THE REGION. HIGH PRESSURE BUILDS OVER THE AREA TUESDAY INTO THE
FIRST HALF OF WEDNESDAY...TO BE FOLLOWED BY A LOW PRESSURE SYSTEM
FOR THURSDAY AND THE POTENTIAL FOR ANOTHER TO END OFF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 627 PM EST MONDAY...ATMOSPHERE OVER THE NORTH COUNTRY THIS
EVENING REMAINS SATURATED WITH PLENTY OF LOW-LEVEL
MOISTURE...OVERCAST SKIES...AND PATCHY AREAS OF MIST. SYNOPTIC
FEATURES INCLUDE A POORLY DEFINED SFC CYCLONE NORTH OF LAKE
ONTARIO...TIED TO AN EQUALLY ILL- DEFINED SHORTWAVE TROUGH OVER
THE NORTHERN GREAT LAKES. THESE WILL BE MOVING NORTHEASTWARD
THROUGH OVERNIGHT. A WEAK WARM FRONTAL BOUNDARY IS EVIDENT IN SFC
OBS EXTENDING ROUGHLY ALONG A LINE FROM OGDENSBURG TO PLATTSBURGH
TO JUST SOUTH OF MONTREAL. LOCALES ON THE NORTH SIDE OF THE
BOUNDARY ARE BELOW FREEZING (INCLUDING THE NORTHERN SAINT LAWRENCE
VALLEY...THE NORTHERN `DACKS AND WESTERN CLINTON/ESSEX COUNTIES IN
NY) AS NORTHEAST WINDS HELPING TO USHER IN TEMPERATURES NEAR 30
DEGREES. LATEST NAM/WRF AND HRRR INDICATE THAT ANY PRECIPITATION
WILL REMAIN IN THIS GENERAL AREA FALLING AS LIGHT SNOW SHOWERS. SO
I`VE CONFINED THE HIGHEST POPS (30% WITH A SLOW TAPER THEREAFTER)
TO THE SAINT LAWRENCE VALLEY AND NORTHERN NEW YORK...WHILE OPTING
FOR A DRY FORECAST FOR CENTRAL AND SOUTHERN VERMONT. THINK THAT
AREAS OF PATCHY FOG (AND FREEZING FOG IN AREAS WHERE TEMPERATURES
ARE SUB- FREEZING) WILL BE POSSIBLE AGAIN TONIGHT DUE TO THE
ABUNDANT LOW- LEVEL MOISTURE AROUND AND LIGHT/CALM WINDS. I DON`T
THINK COVERAGE OF FREEZING FOG WILL BE AS WIDESPREAD AS LAST NIGHT
THOUGH AS TEMPERATURES ARE A FEW DEGREES WARMER THAN YESTERDAY.
I`VE ALSO RAISED TEMPERATURES AND DEWPOINTS UP A FEW DEGREES. THE LACK
OF SIGNIFICANT THERMAL OR DRY ADVECTION AND PRESENCE OF CLOUDINESS
SHOULD KEEP TEMPERATURES AND DEWPOINTS NEAR CURRENT VALUES. FEEL
THAT MOS GUIDANCE IS ONCE AGAIN RUNNING TOO COLD...AND HAVE TRIED
TO BLEND IN WARMER BIAS- CORRECTED DATA TO CURRENT MIN
TEMPERATURES. WITH THESE CHANGES LOWS IN THE MID/UPPER 20S TO THE
LOWER 30S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 313 PM EST MONDAY...GOING INTO TUESDAY...SFC RIDGE WILL BUILD
OVER THE REGION...SHIFTING EAST TUESDAY NIGHT AS MDLS BRING SFC
LOW ACROSS THE GREAT LKS REGION AND JUST TO OUR NORTH FOR WED/WED
NGT. FRONT IS EXPECTED TO BEGIN TO TRAVERSE THE CWA BY MIDDAY
WEDNESDAY INTO WED NGT. FOR PRECIP DURING THESE PERIOD...CWA WILL
SEE LINGERING LIGHT -SW OVER PORTIONS OF NORTHERN ZONES TUESDAY
MORNING BFR HIGH PRESSURE ARRIVES. NEXT ROUND OF PRECIP ARRIVES
WITH FRNTL BOUNDARY MIDDAY WED IN THE ST LAW VALLEY...
OVERSPREADING REST OF CWA THRU THE OVERNGT HRS WEDNESDAY.
SOUTHERLY WINDS AHEAD OF FRNT WILL ALLOW FOR MIX OF RW/SW AT ONSET
THEN TRANSITION TO -SW LATE IN DAY THRU NIGHTTIME HRS. SYSTEM
FAIRLY PROGRESSIVE WITH LIGHT ACCUM POSSIBLE...MAINLY OVER HIR
TRRN. TEMPS NEAR TO ABV NORMAL FOR HIGHS AIDED BY CLRING SKIES
TUESDAY AND WAA ON SOUTHERLY FLOW WEDNESDAY. MAINLY MID/UPPER 30S
W/ SOME 40F IN SPOTS. OVERNGT LOWS COLDEST TUESDAY NIGHT WITH
RIDGE OVERHEAD WITH NUMBERS RANGING FROM THE MID/UPPER TEENS IN
HIR ELEV THRU THE MID 20S ELSEWHERE. WED NGT LOWS DROP LITTLE AS
FLOW BEHIND FRONT REMAINS WSW. NUMBERS WILL RANGE IN THE UPPER 20S
THRU THE MID 30S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 352 PM EST MONDAY...ECMWF AND GFS MODELS SHOWING SOME
DIFFERENCES AS TO TIMING OF THE PRECIPITATION. ON THURSDAY...GFS
MODEL ENDS PRECIPITATION EARLIER THAN THE ECMWF MODEL. THE ECMWF
MODEL SHOWING PRECIPITATION CONTINUING INTO THURSDAY NIGHT. THE
GFS MODEL BRINGS PRECIPITATION INTO THE REGION AFTER MIDNIGHT
THURSDAY NIGHT. MODELS BRING MORE PRECIPITATION INTO THE REGION
FRIDAY AND FRIDAY NIGHT AS BOTH THE ECMWF AND GFS SHOWING MOISTURE
STREAMING NORTHEAST FROM THE LOWER MISSISSIPPI AND TENNESSEE
VALLEYS. ECMWF AND GFS MODELS IN GOOD AGREEMENT SATURDAY AND
SUNDAY WITH COLDER AIR MOVING INTO THE REGION WITH HIGH PRESSURE
BUILDING SLOWLY EAST FROM THE WESTERN GREAT LAKES...WITH MAINLY
FAIR AND DRY WEATHER BUT COLDER TEMPERATURES EXPECTED ON SATURDAY
AND SUNDAY. SUNDAY NIGHT... ECMWF AND GFS MODELS SHOWING PLENTY OF
MOISTURE BEING PULLED NORTHEAST FROM THE GULF COAST AND THE
TENNESSEE AND OHIO VALLEYS AS A LOW PRESSURE AREA MOVE NORTHEAST
THROUGH THE OHIO VALLEY. BOTH THE ECMWF AND GFS MODELS HINT AT A
SECONDARY LOW PRESSURE AREA DEVELOPING ALONG THE MID ATLANTIC
COAST LATE SUNDAY NIGHT. HOWEVER...GFS MODEL IS A BIT FASTER WITH
THIS THAN THE ECMWF MODEL. WILL LEAN TOWARD THE SLOWER DEVELOPMENT
OF THE ECMWF MODEL AND WILL HOLD OFF BRINGING SNOW INTO THE REGION
UNTIL AFTER MIDNIGHT SUNDAY NIGHT... ESPECIALLY GIVEN THE STRONG
RIDGE OF HIGH PRESSURE AND DRY AIR THAT WILL BE OVER THE REGION
DURING THE DAY ON SUNDAY. HAVE ALSO GONE WITH A CHANCE FOR SNOW ON
MONDAY...BUT STILL A BIT EARLY AS TO WHETHER THERE WILL BE ANY
MIXED PRECIPITATION DURING THE DAY ON MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
THROUGH 00Z WEDNESDAY...VERY WEAK WINDS AND NEAR SATURATED LOW-
LEVEL CONDITIONS WILL ALLOW ABUNDANT MVFR AND LOCALIZED IFR
CEILINGS/VSBY CONDITIONS TO PERSIST THROUGH TUESDAY MORNING AT THE
TAF SITES. LIGHT RAIN SHOWERS WILL EXIST AT PBG/BTV THROUGH
03Z...BUT OTHERWISE CONDITIONS WILL GENERALLY BE CLOUDY BUT DRY.
TEMPERATURES WILL HOVER WITHIN A FEW DEGREES OF
FREEZING...GENERALLY JUST ABOVE AT PBG/BTV OVERNIGHT. MAY SEE A BIT
OF FREEZING ON SURFACES AT SLK/MPV WITH FREEZING FOG...BUT NOT AS
WIDESPREAD AS LAST NIGHT WITH TEMPS SEVERAL DEGREES WARMER THAN 24
HRS AGO. VISIBILITY/CEILINGS IMPROVE TO GENERALLY MVFR/VFR DURING
TUESDAY AFTERNOON WITH WINDS BECOMING LIGHT N-NW AROUND 3-5 KTS.
OUTLOOK 00Z WEDNESDAY THROUGH SATURDAY...
00Z WEDNESDAY THROUGH 12Z WEDNESDAY...MVFR/IFR IN LOW CEILINGS AND
ALONG WITH SOME AREAS OF VFR.
12Z WEDNESDAY THROUGH 06Z THURSDAY...MAINLY VFR AS WEAK RIDGE OF
HIGH PRESSURE WILL BE OVER THE REGION.
06Z THURSDAY THROUGH 12Z SATURDAY...AREAS OF MVFR/IFR IN LIGHT
RAIN AND SNOW.
12Z SATURDAY THROUGH 00Z SUNDAY...BECOMING VFR.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JN
NEAR TERM...JN/LOCONTO
SHORT TERM...JN
LONG TERM...WGH
AVIATION...BANACOS/WGH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
627 PM EST MON DEC 2 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE OVER THE EASTERN GREAT LAKES WILL SHIFT INTO
SOUTHERN QUEBEC INTO TUESDAY...PROVIDING LIGHT PRECIPITATION TO MUCH
OF THE REGION. HIGH PRESSURE BUILDS OVER THE AREA TUESDAY INTO THE
FIRST HALF OF WEDNESDAY...TO BE FOLLOWED BY A LOW PRESSURE SYSTEM
FOR THURSDAY AND THE POTENTIAL FOR ANOTHER TO END OFF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 627 PM EST MONDAY...ATMOSPHERE OVER THE NORTH COUNTRY THIS
EVENING REMAINS SATURATED WITH PLENTY OF LOW-LEVEL
MOISTURE...OVERCAST SKIES...AND PATCHY AREAS OF MIST. SYNOPTIC
FEATURES INCLUDE A POORLY DEFINED SFC CYCLONE NORTH OF LAKE
ONTARIO...TIED TO AN EQUALLY ILL- DEFINED SHORTWAVE TROUGH OVER
THE NORTHERN GREAT LAKES. THESE WILL BE MOVING NORTHEASTWARD
THROUGH OVERNIGHT. A WEAK WARM FRONTAL BOUNDARY IS EVIDENT IN SFC
OBS EXTENDING ROUGHLY ALONG A LINE FROM OGDENSBURG TO PLATTSBURGH
TO JUST SOUTH OF MONTREAL. LOCALES ON THE NORTH SIDE OF THE
BOUNDARY ARE BELOW FREEZING (INCLUDING THE NORTHERN SAINT LAWRENCE
VALLEY...THE NORTHERN `DACKS AND WESTERN CLINTON/ESSEX COUNTIES IN
NY) AS NORTHEAST WINDS HELPING TO USHER IN TEMPERATURES NEAR 30
DEGREES. LATEST NAM/WRF AND HRRR INDICATE THAT ANY PRECIPITATION
WILL REMAIN IN THIS GENERAL AREA FALLING AS LIGHT SNOW SHOWERS. SO
I`VE CONFINED THE HIGHEST POPS (30% WITH A SLOW TAPER THEREAFTER)
TO THE SAINT LAWRENCE VALLEY AND NORTHERN NEW YORK...WHILE OPTING
FOR A DRY FORECAST FOR CENTRAL AND SOUTHERN VERMONT. THINK THAT
AREAS OF PATCHY FOG (AND FREEZING FOG IN AREAS WHERE TEMPERATURES
ARE SUB- FREEZING) WILL BE POSSIBLE AGAIN TONIGHT DUE TO THE
ABUNDANT LOW- LEVEL MOISTURE AROUND AND LIGHT/CALM WINDS. I DON`T
THINK COVERAGE OF FREEZING FOG WILL BE AS WIDESPREAD AS LAST NIGHT
THOUGH AS TEMPERATURES ARE A FEW DEGREES WARMER THAN YESTERDAY.
I`VE ALSO RAISED TEMPERATURES AND DEWPOINTS UP A FEW DEGREES. THE LACK
OF SIGNIFICANT THERMAL OR DRY ADVECTION AND PRESENCE OF CLOUDINESS
SHOULD KEEP TEMPERATURES AND DEWPOINTS NEAR CURRENT VALUES. FEEL
THAT MOS GUIDANCE IS ONCE AGAIN RUNNING TOO COLD...AND HAVE TRIED
TO BLEND IN WARMER BIAS- CORRECTED DATA TO CURRENT MIN
TEMPERATURES. WITH THESE CHANGES LOWS IN THE MID/UPPER 20S TO THE
LOWER 30S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 313 PM EST MONDAY...GOING INTO TUESDAY...SFC RIDGE WILL BUILD
OVER THE REGION...SHIFTING EAST TUESDAY NIGHT AS MDLS BRING SFC
LOW ACROSS THE GREAT LKS REGION AND JUST TO OUR NORTH FOR WED/WED
NGT. FRONT IS EXPECTED TO BEGIN TO TRAVERSE THE CWA BY MIDDAY
WEDNESDAY INTO WED NGT. FOR PRECIP DURING THESE PERIOD...CWA WILL
SEE LINGERING LIGHT -SW OVER PORTIONS OF NORTHERN ZONES TUESDAY
MORNING BFR HIGH PRESSURE ARRIVES. NEXT ROUND OF PRECIP ARRIVES
WITH FRNTL BOUNDARY MIDDAY WED IN THE ST LAW VALLEY...
OVERSPREADING REST OF CWA THRU THE OVERNGT HRS WEDNESDAY.
SOUTHERLY WINDS AHEAD OF FRNT WILL ALLOW FOR MIX OF RW/SW AT ONSET
THEN TRANSITION TO -SW LATE IN DAY THRU NIGHTTIME HRS. SYSTEM
FAIRLY PROGRESSIVE WITH LIGHT ACCUM POSSIBLE...MAINLY OVER HIR
TRRN. TEMPS NEAR TO ABV NORMAL FOR HIGHS AIDED BY CLRING SKIES
TUESDAY AND WAA ON SOUTHERLY FLOW WEDNESDAY. MAINLY MID/UPPER 30S
W/ SOME 40F IN SPOTS. OVERNGT LOWS COLDEST TUESDAY NIGHT WITH
RIDGE OVERHEAD WITH NUMBERS RANGING FROM THE MID/UPPER TEENS IN
HIR ELEV THRU THE MID 20S ELSEWHERE. WED NGT LOWS DROP LITTLE AS
FLOW BEHIND FRONT REMAINS WSW. NUMBERS WILL RANGE IN THE UPPER 20S
THRU THE MID 30S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 352 PM EST MONDAY...ECMWF AND GFS MODELS SHOWING SOME
DIFFERENCES AS TO TIMING OF THE PRECIPITATION. ON THURSDAY...GFS
MODEL ENDS PRECIPITATION EARLIER THAN THE ECMWF MODEL. THE ECMWF
MODEL SHOWING PRECIPITATION CONTINUING INTO THURSDAY NIGHT. THE
GFS MODEL BRINGS PRECIPITATION INTO THE REGION AFTER MIDNIGHT
THURSDAY NIGHT. MODELS BRING MORE PRECIPITATION INTO THE REGION
FRIDAY AND FRIDAY NIGHT AS BOTH THE ECMWF AND GFS SHOWING MOISTURE
STREAMING NORTHEAST FROM THE LOWER MISSISSIPPI AND TENNESSEE
VALLEYS. ECMWF AND GFS MODELS IN GOOD AGREEMENT SATURDAY AND
SUNDAY WITH COLDER AIR MOVING INTO THE REGION WITH HIGH PRESSURE
BUILDING SLOWLY EAST FROM THE WESTERN GREAT LAKES...WITH MAINLY
FAIR AND DRY WEATHER BUT COLDER TEMPERATURES EXPECTED ON SATURDAY
AND SUNDAY. SUNDAY NIGHT... ECMWF AND GFS MODELS SHOWING PLENTY OF
MOISTURE BEING PULLED NORTHEAST FROM THE GULF COAST AND THE
TENNESSEE AND OHIO VALLEYS AS A LOW PRESSURE AREA MOVE NORTHEAST
THROUGH THE OHIO VALLEY. BOTH THE ECMWF AND GFS MODELS HINT AT A
SECONDARY LOW PRESSURE AREA DEVELOPING ALONG THE MID ATLANTIC
COAST LATE SUNDAY NIGHT. HOWEVER...GFS MODEL IS A BIT FASTER WITH
THIS THAN THE ECMWF MODEL. WILL LEAN TOWARD THE SLOWER DEVELOPMENT
OF THE ECMWF MODEL AND WILL HOLD OFF BRINGING SNOW INTO THE REGION
UNTIL AFTER MIDNIGHT SUNDAY NIGHT... ESPECIALLY GIVEN THE STRONG
RIDGE OF HIGH PRESSURE AND DRY AIR THAT WILL BE OVER THE REGION
DURING THE DAY ON SUNDAY. HAVE ALSO GONE WITH A CHANCE FOR SNOW ON
MONDAY...BUT STILL A BIT EARLY AS TO WHETHER THERE WILL BE ANY
MIXED PRECIPITATION DURING THE DAY ON MONDAY.
&&
.AVIATION /23Z MONDAY THROUGH SATURDAY/...
THROUGH 18Z TUESDAY...VISIBLE SATELLITE LOOP AND SURFACE
OBSERVATIONS SHOWING ABUNDANT LOW CLOUD COVER ACROSS THE REGION
AT THIS TIME...WITH AREAS OF MIST AND FOG. MODEL GUIDANCE SHOWING
A VERY WEAK PRESSURE GRADIENT ACROSS THE REGION DURING THE NEXT 24 HOURS.
THIS WILL MEAN EITHER CALM OR LIGHT AND VARIABLE SURFACE WINDS ACROSS
THE REGION DURING THE NEXT 24 HOURS. THESE LIGHT WINDS WILL ALSO
MEAN VERY LITTLE IN THE WAY OF MIXING DURING THE NEXT 24
HOURS...SO AGAIN LOOKING FOR IFR/LIFR/VLIFR IN LOW CEILINGS AND
FOG ACROSS MOST OF THE REGION DURING THE NEXT 24 HOURS. SOME
EXCEPTION TO THIS WILL BE THE TAF SITES AT KBTV AND KRUT WHERE
VFR/MVFR CONDITIONS ARE LIKELY DURING THE NEXT 24 HOURS.
OUTLOOK 18Z TUESDAY THROUGH SATURDAY...
18Z TUESDAY THROUGH 12Z WEDNESDAY...MVFR/IFR IN LOW CEILINGS AND
ALONG WITH SOME AREAS OF VFR.
12Z WEDNESDAY THROUGH 06Z THURSDAY...MAINLY VFR AS WEAK RIDGE OF
HIGH PRESSURE WILL BE OVER THE REGION.
06Z THURSDAY THROUGH 12Z SATURDAY...AREAS OF MVFR/IFR IN LIGHT
RAIN AND SNOW.
12Z SATURDAY THROUGH 00Z SUNDAY...BECOMING VFR.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JN
NEAR TERM...JN/LOCONTO
SHORT TERM...JN
LONG TERM...WGH
AVIATION...WGH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1203 AM EST SUN DEC 1 2013
.SYNOPSIS...
LOW PRESSURE WILL GRADUALLY DEVELOP OFF THE CAROLINA COAST LATE
TODAY INTO TONIGHT...MOVING OUT TO SEA MONDAY. WEAK HIGH PRESSURE
WILL MOVE ACROSS THE AREA TUESDAY AND OFFSHORE WEDNESDAY...BRINGING
SEVERAL DAYS OF WARM TEMPERATURES LATE THIS WEEK. THE NEXT COLD
FRONT WILL APPROACH FROM THE WEST SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM SUNDAY...CHANGES WITH THIS EARLY AFTERNOON UPDATE
INCLUDING TRIMMING BACK POPS EVEN FURTHER...WITH THE CHANCE OF
MEASURABLE PRECIPITATION NOW CONFINED TO AREAS ALONG AND EAST OF
MYRTLE BEACH...ACME/DELCO...AND BURGAW. ON LAND MY HIGHEST POPS
THROUGH THE AFTERNOON REMAIN ON THE TIP OF CAPE FEAR...ABOUT A 40
PERCENT CHANCE OF 0.01 INCHES OR MORE REACHING THE BOTTOM OF A
HYPOTHETICAL RAIN GAUGE. NO SIGNIFICANT CHANGES HAVE BEEN MADE TO
SKY COVER OR TEMPERATURES. PREVIOUS DISCUSSION FROM 930 AM FOLLOWS...
MODELS OVER THE PAST TWO DAYS HAVE DONE AN ABYSMAL JOB FORECASTING
HOW THE WEATHER HAS ACTUALLY UNFOLDED OVER THE PAST 6-12 HOURS. NOT
ONLY IS ISENTROPIC LIFT STRONGER AND COVERAGE OF SHOWERS MORE
WIDESPREAD NOW OVER THE COASTAL WATERS THAN WAS EXPECTED...BUT THE
06Z GFS AND NAM PLUS THE 12Z RUC PAINT A PICTURE OF DRIER WEATHER
DEVELOPING INTO TONIGHT AS WHAT ISENTROPIC LIFT WE CURRENTLY HAVE
TRICKLES OFFSHORE AND DRIER AIR ARRIVES FROM THE WEST AND SOUTHWEST
WITHIN THE 5000-10000 FOOT LAYER.
COMPARED TO 12Z SOUNDINGS ALL THE MODELS ARE STRUGGLING WITH WHAT IS
GOING ON BELOW 10000 FEET THIS MORNING. THIS WAS PARTICULARLY
APPARENT AT CHS WHERE THE GFS HAD A HORRIBLE HANDLE (TOO WET) ON
MOISTURE WITHIN THE 800-900 MB LAYER. ALL THE MODELS FAILED TO
PROPERLY SHOW WARM TEMPERATURES BETWEEN 850-1000 MB OBSERVED ON THE
MHX SOUNDING. NEEDLESS TO SAY...THIS CASTS DOUBT ON WHAT (IF ANY)
MODEL GUIDANCE IS TRUSTWORTHY GOING FORWARD THROUGH THIS AFTERNOON
INTO TONIGHT.
MY CURRENT IDEA (BASED ON CURRENT RADAR AND SATELLITE IMAGERY
SPRINKLED WITH RUC/HRRR GUIDANCE THROUGH THE AFTERNOON) IS FOR A
MUCH DRIER AFTERNOON THAN WAS EXPECTED. I HAVE REMOVED POPS FOR THE
PEE DEE COUNTIES IN SOUTH CAROLINA AND TRIMMED BACK POPS ALONG THE
COAST TO NO HIGHER THAN 30-40 PERCENT...HIGHEST ACROSS SOUTHPORT/
CAROLINA BEACH. WITH NO PRECIPITATION INLAND AND SATELLITE IMAGERY
SHOWING BREAKS IN THE OVERCAST ACROSS MUCH OF CENTRAL AND EASTERN
SOUTH CAROLINA I HAVE RAISED FORECAST HIGHS BY 3-4 DEGREES FROM
FLORENCE TO LUMBERTON...WITH UPPER 50S EXPECTED FOR MOST AREAS THIS
AFTERNOON. DRIER AIR ARRIVING THIS AFTERNOON WITHIN THE LAYER
CURRENTLY GENERATING ISENTROPIC LIFT AND SHOWERS (6000-10000 FT)
SHOULD LEAD TO DRY CONDITIONS EVEN ALONG THE COAST. SURPRISINGLY...
THIS DRIER TREND MAY EVEN CONTINUE INTO TONIGHT AS THE 06Z MODELS
(FOR WHAT THEY`RE WORTH) SHOWING SHOWERS REMAINING MAINLY OFFSHORE.
LET`S HOPE THE 12Z RUNS CAN LEND A HAND WITH THAT PORTION OF THE
FORECAST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...A SLEW OF SHORTWAVES WILL CROSS THE CAROLINAS,
GA, AND NRN FL ON MONDAY...SOMEWHAT CONGEALING OFF THE SOUTHEAST
COAST LATE IN THE DAY. THE RESULTING SURFACE WAVE OF LOW PRESSURE
THAT HAD BEEN PROGGED TO DEVELOP NOW LOOKS CONSIDERABLY WEAKER.
MORNING RAIN CHANCES ASSOCIATED WITH THIS FEATURE WILL BE FOCUSED
ALONG THE CAPE FEAR/COASTAL NC ZONES BEFORE DECREASING PERHAPS
RAPIDLY LATER IN THE DAY AS DIFFERENTIAL VORTICITY ADVECTION TURNS
QUITE NEGATIVE AND THE LOW LEVEL UPGLIDE LOOKS TO SHUT OFF AS WELL.
TUESDAY THEN BRINGS ZONAL MID LEVEL FLOW THAT SHOULD KEEP THINGS
DRY. AT THE SURFACE THERE WILL WON`T BE MUCH GRADIENT AS A WEAK HIGH
OVER THE CAROLINAS FILLS THE SPACE IN BETWEEN THE DEEPENING ATLANTIC
LOW AND A LARGE SYSTEM GATHERING STRENGTH OVER THE NRN PLAINS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...RIDGE AXIS TO DRIFT OFFSHORE ON WEDNESDAY PAVING
THE WAY FOR SOME RETURN FLOW. EXPECT ABOVE NORMAL HIGHS FOR THE
FIRST TIME IN QUITE A WHILE DESPITE POSSIBLE INCREASE IN LOW TO MID
LEVEL CLOUDINESS. THURSDAY TOO WILL BE MILD AND RATHER CLOUDY AS THE
RETURN FLOW VEERS SOMEWHAT DUE TO THE APPROACH OF A COLD FRONT FROM
THE WEST. THE NE TO SW ORIENTATION OF THE BOUNDARY WILL HAVE IT
QUITE LINED UP WITH THE MID LEVEL FLOW MAKING FOR VERY SLOW
PROGRESSION. IN FACT WE SEE SOME DIFFERENCES IN THE SPEED AT WHICH
THE BOUNDARY APPROACHES AND MOVES THROUGH BETWEEN VARIOUS MODELS.
GIVEN THE VERTICAL DIRECTIONAL ALIGNMENT OF THE FLOW THE SLOWER
SOLUTIONS SEEM MORE PLAUSIBLE.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...MODERATE UNCERTAINTY WITH RESPECT TO CLOUD HEIGHTS. A
COASTAL LOW TRIES TO FORM OVERNIGHT...BUT IT WILL NOT PHASE UNTIL
LATE MONDAY...AFTER IT IS WELL NORTHEAST OF THE REGION. ANY PRECIP
ASSOCIATED WITH IT THIS AFTERNOON WILL BE VERY LIGHT AND PROBABLY
WILL NOT AFFECT VISIBILITY. THINK THE CEILINGS WILL FALL DIURNALLY
THIS EVENING...PERHAPS IFR AT THE MYRTLES MOST OF THE NIGHT. LIGHT
WINDS OVERNIGHT WILL BECOME NORTHERLY MONDAY AFTER THE LOW PULLS TO
THE NORTHEAST. CEILINGS SHOULD IMPROVE TO VFR...HOWEVER IT MAY TAKE
A FEW HOURS AFTER DAYBREAK TO ACCOMPLISH THIS.
EXTENDED OUTLOOK...MAINLY VFR TUESDAY AND WEDNESDAY. LOW CONFIDENCE
FOR SHOWERS THURSDAY AND FRIDAY...MAINLY WEST.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM SUNDAY...NO SIGNIFICANT CHANGES ARE NEEDED FOR THIS
EARLY AFTERNOON UPDATE. PREVIOUS DISCUSSION FROM 930 AM FOLLOWS...
FAIRLY WIDESPREAD SHOWER ACTIVITY COVERS THE OUTER PORTION OF THE
COASTAL WATERS THIS MORNING...EXCEPT NEAR CAPE FEAR WHERE THE
SHOWERS ARE ALSO OCCURRING IN THE NEARSHORE WATERS. THIS IS
OCCURRING IN ASSOCIATION WITH A WEAK COASTAL TROUGH NEAR THE WESTERN
EDGE OF THE GULF STREAM. NORTH WINDS SHOULD VEER A LITTLE MORE
NORTHEASTERLY BY THIS AFTERNOON...WITH NO INCREASE IN WIND SPEEDS
EXPECTED. SEAS ARE THE BIG STORY AWAY FROM SHORE AS A PERSISTENT
9-SECOND EASTERLY SWELL CONTINUES TO BRING SIGNIFICANT WAVE ENERGY
INTO THE AREA. THE GENESIS REGION FOR THIS SWELL IS ACTUALLY WELL
OUT INTO THE CENTRAL ATLANTIC WHERE A COUPLE THOUSAND MILES OF
EASTERLY FLOW ALONG THE SOUTH SIDE OF NORTH ATLANTIC HIGH PRESSURE
IS BUILDING QUITE A WAVE FETCH. SEAS OUT AT FRYING PAN SHOALS ARE
AROUND 5 FEET DUE TO THIS SWELL...WITH 3 FEET REPORTED AT THE BUOY
SEVERAL MILES SOUTH OF THE MOUTH OF THE CAPE FEAR RIVER.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...A SERIES OF CONGEALING UPPER LEVEL DISTURBANCES
WILL FORM A SURFACE LOW OFF THE COAST BY MONDAY MORNING. THIS
FEATURE IS NOW SUPPOSED TO BE WEAKER THAN EARLIER FORECASTS AND
POSSIBLY FURTHER OUT TO SEA AS WELL. THIS INCREASES FORECAST
CONFIDENCE THAT NO ADVISORIES OR HEADLINES WILL BE NEEDED AT THIS
TIME AS WINDS MAY BE CAPPED IN THE 10 TO 15 KT RANGE OVER NORTHERN
ZONES WITH PERHAPS JUST 10 KT SOUTH. EVEN LIGHTER WINDS AND SEAS MAY
BE IN THE OFFERING ON TUESDAY AS THIS SYSTEM EXITS AND ANOTHER
DEVELOPS OVER THE NORTHERN PLAINS...WITH ONLY A WEAK HIGH IN BETWEEN
OVER THE CAROLINAS.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...WIND SWINGS AROUND TO THE SOUTH ON WEDNESDAY AS
THE CENTER OF HIGH PRESSURE MOVES OFF THE COAST. NO REAL INCREASE IN
WIND SPEED TO SPEAK OF HOWEVER SO SEAS MAY ACTUALLY CONTINUE TO
SETTLE SOME FROM THEIR TUESDAY VALUES. A COLD FRONT WILL APPROACH
FROM THE NW ON THURSDAY ALBEIT QUITE SLOWLY AS THE BOUNDARY WILL BE
ALIGNED WITH ITS MID LEVEL STEERING FLOW. THE SLOW APPROACH OF THE
FRONT WILL VEER THE WIND SLIGHTLY AND YIELD A GRADUAL INCREASE IN
WIND SPEED. THIS WILL CONTINUE INTO THURSDAY NIGHT AT WHICH TIME
SEAS WILL START RESPONDING TO THE INCREASED FLOW AND FETCH DURATION.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
947 AM EST SUN DEC 1 2013
.SYNOPSIS...
LOW PRESSURE WILL GRADUALLY DEVELOP OFF THE CAROLINA COAST LATE
TODAY INTO TONIGHT...MOVING OUT TO SEA MONDAY. WEAK HIGH PRESSURE
WILL MOVE ACROSS THE AREA TUESDAY AND OFFSHORE WEDNESDAY...BRINGING
SEVERAL DAYS OF WARM TEMPERATURES LATE THIS WEEK. THE NEXT COLD
FRONT WILL APPROACH FROM THE WEST SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM SUNDAY...MODELS OVER THE PAST TWO DAYS HAVE DONE AN
ABYSMAL JOB FORECASTING HOW THE WEATHER HAS ACTUALLY UNFOLDED OVER
THE PAST 6-12 HOURS. NOT ONLY IS ISENTROPIC LIFT STRONGER AND
COVERAGE OF SHOWERS MORE WIDESPREAD NOW OVER THE COASTAL WATERS THAN
WAS EXPECTED...BUT THE 06Z GFS AND NAM PLUS THE 12Z RUC PAINT A
PICTURE OF DRIER WEATHER DEVELOPING INTO TONIGHT AS WHAT ISENTROPIC
LIFT WE CURRENTLY HAVE TRICKLES OFFSHORE AND DRIER AIR ARRIVES FROM
THE WEST AND SOUTHWEST WITHIN THE 5000-10000 FOOT LAYER.
COMPARED TO 12Z SOUNDINGS ALL THE MODELS ARE STRUGGLING WITH WHAT IS
GOING ON BELOW 10000 FEET THIS MORNING. THIS WAS PARTICULARLY
APPARENT AT CHS WHERE THE GFS HAD A HORRIBLE HANDLE (TOO WET) ON
MOISTURE WITHIN THE 800-900 MB LAYER. ALL THE MODELS FAILED TO
PROPERLY SHOW WARM TEMPERATURES BETWEEN 850-1000 MB OBSERVED ON THE
MHX SOUNDING. NEEDLESS TO SAY...THIS CASTS DOUBT ON WHAT (IF ANY)
MODEL GUIDANCE IS TRUSTWORTHY GOING FORWARD THROUGH THIS AFTERNOON
INTO TONIGHT.
MY CURRENT IDEA (BASED ON CURRENT RADAR AND SATELLITE IMAGERY
SPRINKLED WITH RUC/HRRR GUIDANCE THROUGH THE AFTERNOON) IS FOR A
MUCH DRIER AFTERNOON THAN WAS EXPECTED. I HAVE REMOVED POPS FOR THE
PEE DEE COUNTIES IN SOUTH CAROLINA AND TRIMMED BACK POPS ALONG THE
COAST TO NO HIGHER THAN 30-40 PERCENT...HIGHEST ACROSS SOUTHPORT/
CAROLINA BEACH. WITH NO PRECIPITATION INLAND AND SATELLITE IMAGERY
SHOWING BREAKS IN THE OVERCAST ACROSS MUCH OF CENTRAL AND EASTERN
SOUTH CAROLINA I HAVE RAISED FORECAST HIGHS BY 3-4 DEGREES FROM
FLORENCE TO LUMBERTON...WITH UPPER 50S EXPECTED FOR MOST AREAS THIS
AFTERNOON. DRIER AIR ARRIVING THIS AFTERNOON WITHIN THE LAYER
CURRENTLY GENERATING ISENTROPIC LIFT AND SHOWERS (6000-10000 FT)
SHOULD LEAD TO DRY CONDITIONS EVEN ALONG THE COAST. SURPRISINGLY...
THIS DRIER TREND MAY EVEN CONTINUE INTO TONIGHT AS THE 06Z MODELS
(FOR WHAT THEY`RE WORTH) SHOWING SHOWERS REMAINING MAINLY OFFSHORE.
LET`S HOPE THE 12Z RUNS CAN LEND A HAND WITH THAT PORTION OF THE
FORECAST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...A SLEW OF SHORTWAVES WILL CROSS THE CAROLINAS,
GA, AND NRN FL ON MONDAY...SOMEWHAT CONGEALING OFF THE SOUTHEAST
COAST LATE IN THE DAY. THE RESULTING SURFACE WAVE OF LOW PRESSURE
THAT HAD BEEN PROGGED TO DEVELOP NOW LOOKS CONSIDERABLY WEAKER.
MORNING RAIN CHANCES ASSOCIATED WITH THIS FEATURE WILL BE FOCUSED
ALONG THE CAPE FEAR/COASTAL NC ZONES BEFORE DECREASING PERHAPS
RAPIDLY LATER IN THE DAY AS DIFFERENTIAL VORTICITY ADVECTION TURNS
QUITE NEGATIVE AND THE LOW LEVEL UPGLIDE LOOKS TO SHUT OFF AS WELL.
TUESDAY THEN BRINGS ZONAL MID LEVEL FLOW THAT SHOULD KEEP THINGS
DRY. AT THE SURFACE THERE WILL WON`T BE MUCH GRADIENT AS A WEAK HIGH
OVER THE CAROLINAS FILLS THE SPACE IN BETWEEN THE DEEPENING ATLANTIC
LOW AND A LARGE SYSTEM GATHERING STRENGTH OVER THE NRN PLAINS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...RIDGE AXIS TO DRIFT OFFSHORE ON WEDNESDAY PAVING
THE WAY FOR SOME RETURN FLOW. EXPECT ABOVE NORMAL HIGHS FOR THE
FIRST TIME IN QUITE A WHILE DESPITE POSSIBLE INCREASE IN LOW TO MID
LEVEL CLOUDINESS. THURSDAY TOO WILL BE MILD AND RATHER CLOUDY AS THE
RETURN FLOW VEERS SOMEWHAT DUE TO THE APPROACH OF A COLD FRONT FROM
THE WEST. THE NE TO SW ORIENTATION OF THE BOUNDARY WILL HAVE IT
QUITE LINED UP WITH THE MID LEVEL FLOW MAKING FOR VERY SLOW
PROGRESSION. IN FACT WE SEE SOME DIFFERENCES IN THE SPEED AT WHICH
THE BOUNDARY APPROACHES AND MOVES THROUGH BETWEEN VARIOUS MODELS.
GIVEN THE VERTICAL DIRECTIONAL ALIGNMENT OF THE FLOW THE SLOWER
SOLUTIONS SEEM MORE PLAUSIBLE.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 12Z...QUITE A BIT OF STRATA CUMULUS OVER THE CWA...LOWEST AT
THE MYRTLES. THE STRATA CU WILL BE IN AND OUT...REPLACED WITH A MID
CLOUD CEILING THIS AFTERNOON. THE GRADIENT WILL BE VERY WEAK TODAY
WITH HIGH PRESSURE CENTERED OVERHEAD...PERHAPS LIGHT AND VARIABLE
WOULD BEST DESCRIBE THE WINDS TODAY. LOW PRESSURE DEVELOPS OFFSHORE
TONIGHT...WITH A FEW SPRINKLES POSSIBLE. AN MVFR CEILING IS POSSIBLE
THIS EVENING.
EXTENDED OUTLOOK...CHANCE OF RAIN ON MONDAY WITH INTERMITTENT
MVFR/IFR CONDITIONS EXPECTED. MAINLY VFR TUESDAY THROUGH THURSDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM SUNDAY...FAIRLY WIDESPREAD SHOWER ACTIVITY COVERS THE
OUTER PORTION OF THE COASTAL WATERS THIS MORNING...EXCEPT NEAR CAPE
FEAR WHERE THE SHOWERS ARE ALSO OCCURRING IN THE NEARSHORE WATERS.
THIS IS OCCURRING IN ASSOCIATION WITH A WEAK COASTAL TROUGH NEAR THE
WESTERN EDGE OF THE GULF STREAM. NORTH WINDS SHOULD VEER A LITTLE
MORE NORTHEASTERLY BY THIS AFTERNOON...WITH NO INCREASE IN WIND
SPEEDS EXPECTED. SEAS ARE THE BIG STORY AWAY FROM SHORE AS A
PERSISTENT 9-SECOND EASTERLY SWELL CONTINUES TO BRING SIGNIFICANT
WAVE ENERGY INTO THE AREA. THE GENESIS REGION FOR THIS SWELL IS
ACTUALLY WELL OUT INTO THE CENTRAL ATLANTIC WHERE A COUPLE THOUSAND
MILES OF EASTERLY FLOW ALONG THE SOUTH SIDE OF NORTH ATLANTIC HIGH
PRESSURE IS BUILDING QUITE A WAVE FETCH. SEAS OUT AT FRYING PAN
SHOALS ARE AROUND 5 FEET DUE TO THIS SWELL...WITH 3 FEET REPORTED AT
THE BUOY SEVERAL MILES SOUTH OF THE MOUTH OF THE CAPE FEAR RIVER.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...A SERIES OF CONGEALING UPPER LEVEL DISTURBANCES
WILL FORM A SURFACE LOW OFF THE COAST BY MONDAY MORNING. THIS
FEATURE IS NOW SUPPOSED TO BE WEAKER THAN EARLIER FORECASTS AND
POSSIBLY FURTHER OUT TO SEA AS WELL. THIS INCREASES FORECAST
CONFIDENCE THAT NO ADVISORIES OR HEADLINES WILL BE NEEDED AT THIS
TIME AS WINDS MAY BE CAPPED IN THE 10 TO 15 KT RANGE OVER NORTHERN
ZONES WITH PERHAPS JUST 10 KT SOUTH. EVEN LIGHTER WINDS AND SEAS MAY
BE IN THE OFFERING ON TUESDAY AS THIS SYSTEM EXITS AND ANOTHER
DEVELOPS OVER THE NORTHERN PLAINS...WITH ONLY A WEAK HIGH IN BETWEEN
OVER THE CAROLINAS.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...WIND SWINGS AROUND TO THE SOUTH ON WEDNESDAY AS
THE CENTER OF HIGH PRESSURE MOVES OFF THE COAST. NO REAL INCREASE IN
WIND SPEED TO SPEAK OF HOWEVER SO SEAS MAY ACTUALLY CONTINUE TO
SETTLE SOME FROM THEIR TUESDAY VALUES. A COLD FRONT WILL APPROACH
FROM THE NW ON THURSDAY ALBEIT QUITE SLOWLY AS THE BOUNDARY WILL BE
ALIGNED WITH ITS MID LEVEL STEERING FLOW. THE SLOW APPROACH OF THE
FRONT WILL VEER THE WIND SLIGHTLY AND YIELD A GRADUAL INCREASE IN
WIND SPEED. THIS WILL CONTINUE INTO THURSDAY NIGHT AT WHICH TIME
SEAS WILL START RESPONDING TO THE INCREASED FLOW AND FETCH DURATION.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...43
AREA FORECAST DISCUSSION
NWS RALEIGH NC
647 AM EST SUN DEC 1 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS OVER THE REGION TODAY. LOW PRESSURE DEVELOPS
ALONG THE CAROLINA COAST TONIGHT AND GRADUALLY STRENGTHENS AS IT
MOVES AWAY FROM THE REGION MONDAY. HIGH PRESSURE THEN RETURNS FOR
TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 300 AM SUNDAY...
THE SURFACE RIDGE AXIS EXTENDED NORTHEAST TO SOUTHWEST ACROSS
CENTRAL NORTH CAROLINA...WITH A SLACK GRADIENT IN PLACE. IN A FAST
WESTERLY FLOW ALOFT...AS ONE MID-LEVEL SHORTWAVE EXITED CENTRAL
NORTH CAROLINA TO THE EAST...ANOTHER WAS MOVING IN FROM THE TENNESEE
VALLEY. THE 00Z RAOB ANALYSIS SHOWED GREATER 850MB AND 700MB
MOISTURE JUST TO OUR SOUTH...AND SOME OF THIS MOISTURE HAS ADVECTED
NORTH...TO ABOUT U.S. 64. THE NAM AND THE GFS ARE FAIRLY SIMILAR AND
BOTH HAVE TRENDED DRIER CERTAINLY FROM THE PREVIOUS 00Z RUN...SUCH
THAT THE MID LEVELS TEND TO BE FAIRLY DRY FOR MUCH OF THE DAY
TODAY...WITH THE GREATEST MID-LEVEL MOISTURE OVER THE SOUTHERN
COASTAL PLAIN RELATIVE TO THE REST OF CENTRAL NORTH CAROLINA. THE
BEST 850MB LIFT IS CERTAINLY IN THE SOUTHEAST PART OF CENTRAL NORTH
CAROLINA TODAY WHERE 850MB THETA-E ADVECTION IS GREATEST. FAINT
RADAR RETURNS AND GUIDANCE FROM THE HRRR WRF SUGGEST A SMALL CHANCE
OF SPRINKLES IN THE SANDHILLS AND SOUTHERN COASTAL PLAIN THIS
MORNING...WITH A CHANCE OF RAIN MAINLY THIS AFTERNOON ALONG AND
SOUTH OF A LINE FROM ABOUT KRWI TO KRCZ...WITH THE BEST CHANCE
TOWARD KCTZ IN VICINITY OF GREATER MOISTURE AND LIFT.
PRECIPITATION...IF ANY...SHOULD BE LIGHT...WITH THE GREATER
PROBABILITY OF PLURAL HUNDREDTHS IN SAMPSON AND POSSIBLY INTO WAYNE
COUNTIES AS OF THIS WRITING.
1000-850MB THICKNESSES WOULD SUPPORT WARMER TEMPERATURES THAN
FORECAST BY ABOUT A CATEGORY...BUT A BLEND OF GUIDANCE WORKED WELL
FOR SATURDAY HIGHS...AND WILL FOLLOW THE SAME FOR TODAY. FEWER AND
THINNER CLOUDS NORTHWEST...MORE TOWARD THE SOUTHEAST BUT WITH HIGHER
THICKNESSES AND MORE MOIST...RESULT IN A FAIRLY UNIFORM TEMPERATURE
FORECAST IN THE LOWER TO POSSIBLY MID 50S. WINDS SHOULD BE
LIGHT...WITH THE RELATIVELY GREATER SPEEDS TOWARD THE TRIAD...WHILE
STILL UNDER 10KT...FROM THE SOUTHWEST...WEST OF THE SURFACE RIDGE
AXIS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
AS OF 300 AM SUNDAY...
AGAIN THE NAM AND GFS ARE FAIRLY SIMILAR IN THE EVOLUTION OF THE
SURFACE LOW ALONG THE COAST...WITH AN INVERTED TROUGH DEVELOPING
EARLY TONIGHT FOLLOWED BY WEAK CYCLOGENESIS OVERNIGHT...THEN LOW
PRESSURE GRADUALLY STRENGTHENING MONDAY AS IT MOVES AWAY FROM THE
COASTAL CAROLINAS. 850MB LIFT IS NOT VERY STRONG OVERNIGHT INTO
MONDAY AFTERNOON...WITH THE GFS IN PARTICULAR HAVING TRENDED FARTHER
SOUTH WITH THE PASSAGE OF ITS MODERATE MID-LEVEL SHORTWAVE
ACCOMPANYING THE MID-LEVEL TROUGH. JET SUPPORT ALSO LOOKS TO HAVE
SHIFTED FARTHER SOUTH COMPARED TO RECENT RUNS. K INDICES ARE HIGHEST
TOWARD THE COAST LATE TONIGHT AND MONDAY MORNING...BUT 850MB THETA-E
STILL REMAINS MODEST WEST THROUGH THE COASTAL PLAIN...AND WITH THE
WEAK LIFT AS LOW PRESSURE ORGANIZES JUST OFFSHORE...WILL CONTINUE AT
LEAST A CHANCE OF RAIN EARLY TONIGHT MAINLY EAST OF INTERSTATE 95
WHEN OVERALL MOISTURE APPEARS HIGHEST FOR THE NIGHTTIME HOURS...
THEN AGAIN MAINLY MONDAY MORNING ALONG AND EAST OF ABOUT U.S. 1
DURING A PERIOD OF A MODEST INCREASE IN MID-LEVEL MOISTURE IN
CONJUNCTION WITH GOOD LOWER-LEVEL MOISTURE. FOR NOW WILL KEEP
CHANCES BELOW LIKELY GIVEN THE DRIER MODEL TRENDS...NO MOS GUIDANCE
IN CENTRAL NORTH CAROLINA CLOSE TO LIKELY...AND NAM AND GFS MODEL
QPF BEING PRETTY LOW. PLAN TO KEEP THE TRIAD AND THE FAR WESTERN
PIEDMONT DRY THIS PERIOD.
850MB THETA-E TROUGHINESS STARTS TO PUSH EAST MONDAY AFTERNOON WITH
INCREASING SUBSIDENCE. BUFR SOUNDINGS ARE FAIRLY STABLE AND DRYING
CERTAINLY BY 00Z TUESDAY...AND PRECIPITABLE WATER VALUES ARE AT OR
BELOW A HALF-INCH MONDAY NIGHT. WILL NOTE CHANCES BELOW SLIGHT IN
CENTRAL NORTH CAROLINA BY 00Z TUESDAY. LOWS TONIGHT AND HIGHS MONDAY
ARE A LITTLE TRICKY GIVEN THE UNCERTAINTY SURROUNDING CLOUD COVER
AND THE POTENTIAL VARIABLE THICKNESS OF SUCH CLOUD COVER. OPTED TO
TRIM LOWS TONIGHT SLIGHTLY ESPECIALLY ALONG AND NORTH OF INTERSTATE
85 WHERE CLOUD COVER SHOULD BE LEAST AND THINNEST OVERNIGHT. GIVEN
THE DRIER MODEL TREND OPTED TO RAISE MAXES INTO THE 50S THROUGHOUT
CENTRAL NORTH CAROLINA MONDAY...STILL KEEPING THE WARMER READINGS
OVER THE WESTERN PIEDMONT FOR NOW. OVERNIGHT LOWS MONDAY NIGHT NEAR
THE COOLER MAV MOS GUIDANCE ANTICIPATING FEWER CLOUDS...LOWER TO MID
30S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
WEAK HIGH PRESSURE WILL BUILD INTO THE REGION ON TUESDAY IN THE WAKE
OF THE DEPARTING COASTAL CYCLONE AS A WESTERLY FLOW DEVELOPS ALOFT.
FAIR WEATHER IS EXPECTED IN CENTRAL NC WITH A FEW LAYERS OF CLOUDS.
HIGHS WILL RANGE IN THE LOWER 50S NORTHEAST TO NEAR 60 TOWARD THE SC
BORDER.
HEIGHTS BEGIN RISING ON WEDNESDAY AND THURSDAY AS A BROAD TROUGH
DEVELOPS IN THE ROCKIES AND THE NORTHERN PLAINS. AN INCREASINGLY
MOIST SOUTHERLY FLOW WILL PROMOTE AN INCREASE IN CLOUDINESS ON
WEDNESDAY AND THURSDAY WITH WARMING TEMPERATURES ESPECIALLY ON
THURSDAY. BOTH THE EC EFS AND THE GFS HIGHLIGHT A SHALLOW
DISTURBANCE THAT WILL MOVE NORTHEAST ACROSS THE AREA ON WEDNESDAY
THAT SHOWS UP AS A REGION OF ISENTROPIC UPGLIDE IN THE 290-295
LAYER. DON`T EXPECT ANY PRECIPITATION AT THIS TIME BUT HAVE
INCREASED CLOUD PERCENTAGES DURING THE PERIOD. GFS BUFR SOUNDINGS
ALSO SUGGEST THAT THERE COULD BE SOME GUSTY WINDS ON WEDNESDAY
AFTERNOON WITH GUSTS UP TO 20-25 MPH AS MIXING TAPS INTO THE
STRONGER FLOW ASSOCIATED WITH THE LOW LEVEL JET. A SLIGHTLY BETTER
CHANCE OF RAIN ARRIVES IN THE NORTHWESTERN PORTION OF THE FORECAST
AREA LATE THURSDAY AND ESPECIALLY THURSDAY NIGHT AS A COLD FRONT
APPROACHES THE REGION FROM THE WEST. TEMPERATURES SHOULD WARM INTO
THE MID 50S TO NEAR 60 ON ON WEDNESDAY AND THEN THE 60S TO NEAR 70
ON THURSDAY.
DIFFERENCES IN THE GFS AND EC EFS BECOME MORE APPARENT ON FRIDAY AND
ESPECIALLY SATURDAY WITH THE GFS BEING FASTER AND PUSHING THE FRONT
THROUGH THE AREA LATE FRI/EARLY SAT WITH THE EC PERHAPS 12 HOURS
SLOWER. WHILE THE BEST FORCING FOR ASCENT STAYS NORTH OF THE
AREA...THE PLUME OF DEEP LAYER MOISTURE AND FORCING ASSOCIATED WITH
THE FRONT SHOULD BE SUFFICIENT FOR CHC POPS. MILD TEMPERATURES ARE
EXPECTED ON FRIDAY AHEAD OF THE FRONT AND AHEAD OF THE MAIN AREA OF
RAIN. MAX TEMPS HAVE BEEN ADJUSTED UPWARD INTO THE UPPER 60S
NORTHWEST TO NEAR 75 IN THE SOUTHEAST. ALSO ADJUSTED MIN TEMPS ON
SATURDAY UPWARD TO ACCOUNT FOR THE CLOUDS AND MILD CONDITIONS AHEAD
OF THE FRONT. MAX TEMPS ON SATURDAY WILL BE LIMITED GIVEN THE CLOUDS
AND AREAS OF LIGHT RAIN BUT STILL EXPECT TEMPS TO REACH THE UPPER
50S NORTHWEST TO MID 60S SOUTHEAST. AT THIS POINT WE DON`T EXPECT
ANY THUNDERSTORMS LATE FRIDAY INTO SATURDAY THUNDERSTORMS GIVEN THE
MARGINAL MID LEVEL LAPSE RATES.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 645 AM SUNDAY...
MOSTLY VFR CONDITIONS WILL CONTINUE THROUGH THE 12Z VALID TAF
PERIOD. AREAS OF MVFR CONDITIONS NEAR INTERSTATE 95...EVEN VERY
BRIEFLY IFR AT KRWI...SHOULD END BY 14Z BASED ON TRENDS ON
OBSERVATIONS AND THE SATELLITE FOG PRODUCT. MAINLY DURING THE
AFTERNOON AND EVENING PATCHY LIGHT RAIN IS POSSIBLE SOUTH OF A LINE
FROM ABOUT KFAY TO KRWI. THIS IS WHERE ANY THICKER CLOUDS SHOULD
RESIDE DURING THAT TIME...THOUGH THEY ARE EXPECTED CURRENTLY TO HAVE
THE HIGHEST PROBABILITY OF BEING VFR. WITH HIGH PRESSURE OVERHEAD...
WINDS SHOULD BE SOMEWHAT VARIABLE. JUST ON THE WEST SIDE OF THE
SURFACE RIDGE AXIS...WINDS SHOULD BE MORE SOUTHWEST TOWARD THE
TRIAD. WINDS SHOULD TEND TO FAVOR NORTHERLY TOWARD KFAY. AT KRWI AND
ESPECIALLY KRDU...THE LIGHT SURFACE WIND DIRECTION IS MORE
CHALLENGING...BUT WILL CONTINUE TO LEAN WESTERLY DURING THE DAYLIGHT
HOURS WITH THE CONSENSUS OF GUIDANCE BEING CONSISTENT IN SHOWING
THAT DIRECTION...THOUGH IT COULD BE QUITE VARIABLE.
BEYOND THE 12Z VALID TAF PERIOD...VFR CONDITIONS WILL BE FORECAST.
AN ALTERNATIVE IS THE PROBABILITY OF SUB-VFR CONDITIONS OVERNIGHT
INTO MONDAY MORNING IN CLOUDS AND PATCHY LIGHT RAIN ALONG AND EAST
OF INTERSTATE 95...LEANING MVFR AS A CATEGORY IF IT OCCURS...WITH A
CHANCE OF SUB-VFR CONDITIONS IN LIGHT FOG TOWARD THE TRIAD WHERE
CLOUDS SHOULD BE LESSER AND THINNER. KRDU WILL BE IN BETWEEN...AND
IT IS POSSIBLE FOR A PERIOD OF BOTH LIGHT FOG AND LOWER CLOUDS THERE
BEFORE DRIER AIR AND SUBSIDENCE MOVE IN FROM THE WEST...CREATING
WIDESPREAD VFR CONDITIONS ACROSS CENTRAL NORTH CAROLINA BY LATE
MONDAY AFTERNOON. MVFR CONDITIONS IN FOG ARE POSSIBLE LATE MONDAY
NIGHT AND EARLY TUESDAY...THEN AS MOISTURE INCREASES...THERE IS A
CHANCE OF SUB-VFR CONDITIONS IN LOW CLOUDS TUESDAY NIGHT INTO
WEDNESDAY...WITH GREATER CHANCES OF THOSE CONDITIONS CURRENTLY
TOWARD THE TRIAD THOUGH POSSIBLE THROUGHOUT CENTRAL NORTH CAROLINA
PARTICULARLY WEDNESDAY NIGHT.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...BLAES
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
303 AM EST SUN DEC 1 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS OVER THE REGION TODAY. LOW PRESSURE DEVELOPS
ALONG THE CAROLINA COAST TONIGHT AND GRADUALLY STRENGTHENS AS IT
MOVES AWAY FROM THE REGION MONDAY. HIGH PRESSURE THEN RETURNS FOR
TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 300 AM SUNDAY...
THE SURFACE RIDGE AXIS EXTENDED NORTHEAST TO SOUTHWEST ACROSS
CENTRAL NORTH CAROLINA...WITH A SLACK GRADIENT IN PLACE. IN A FAST
WESTERLY FLOW ALOFT...AS ONE MID-LEVEL SHORTWAVE EXITED CENTRAL
NORTH CAROLINA TO THE EAST...ANOTHER WAS MOVING IN FROM THE TENNESEE
VALLEY. THE 00Z RAOB ANALYSIS SHOWED GREATER 850MB AND 700MB
MOISTURE JUST TO OUR SOUTH...AND SOME OF THIS MOISTURE HAS ADVECTED
NORTH...TO ABOUT U.S. 64. THE NAM AND THE GFS ARE FAIRLY SIMILAR AND
BOTH HAVE TRENDED DRIER CERTAINLY FROM THE PREVIOUS 00Z RUN...SUCH
THAT THE MID LEVELS TEND TO BE FAIRLY DRY FOR MUCH OF THE DAY
TODAY...WITH THE GREATEST MID-LEVEL MOISTURE OVER THE SOUTHERN
COASTAL PLAIN RELATIVE TO THE REST OF CENTRAL NORTH CAROLINA. THE
BEST 850MB LIFT IS CERTAINLY IN THE SOUTHEAST PART OF CENTRAL NORTH
CAROLINA TODAY WHERE 850MB THETA-E ADVECTION IS GREATEST. FAINT
RADAR RETURNS AND GUIDANCE FROM THE HRRR WRF SUGGEST A SMALL CHANCE
OF SPRINKLES IN THE SANDHILLS AND SOUTHERN COASTAL PLAIN THIS
MORNING...WITH A CHANCE OF RAIN MAINLY THIS AFTERNOON ALONG AND
SOUTH OF A LINE FROM ABOUT KRWI TO KRCZ...WITH THE BEST CHANCE
TOWARD KCTZ IN VICINITY OF GREATER MOISTURE AND LIFT.
PRECIPITATION...IF ANY...SHOULD BE LIGHT...WITH THE GREATER
PROBABILITY OF PLURAL HUNDREDTHS IN SAMPSON AND POSSIBLY INTO WAYNE
COUNTIES AS OF THIS WRITING.
1000-850MB THICKNESSES WOULD SUPPORT WARMER TEMPERATURES THAN
FORECAST BY ABOUT A CATEGORY...BUT A BLEND OF GUIDANCE WORKED WELL
FOR SATURDAY HIGHS...AND WILL FOLLOW THE SAME FOR TODAY. FEWER AND
THINNER CLOUDS NORTHWEST...MORE TOWARD THE SOUTHEAST BUT WITH HIGHER
THICKNESSES AND MORE MOIST...RESULT IN A FAIRLY UNIFORM TEMPERATURE
FORECAST IN THE LOWER TO POSSIBLY MID 50S. WINDS SHOULD BE
LIGHT...WITH THE RELATIVELY GREATER SPEEDS TOWARD THE TRIAD...WHILE
STILL UNDER 10KT...FROM THE SOUTHWEST...WEST OF THE SURFACE RIDGE
AXIS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
AS OF 300 AM SUNDAY...
AGAIN THE NAM AND GFS ARE FAIRLY SIMILAR IN THE EVOLUTION OF THE
SURFACE LOW ALONG THE COAST...WITH AN INVERTED TROUGH DEVELOPING
EARLY TONIGHT FOLLOWED BY WEAK CYCLOGENESIS OVERNIGHT...THEN LOW
PRESSURE GRADUALLY STRENGTHENING MONDAY AS IT MOVES AWAY FROM THE
COASTAL CAROLINAS. 850MB LIFT IS NOT VERY STRONG OVERNIGHT INTO
MONDAY AFTERNOON...WITH THE GFS IN PARTICULAR HAVING TRENDED FARTHER
SOUTH WITH THE PASSAGE OF ITS MODERATE MID-LEVEL SHORTWAVE
ACCOMPANYING THE MID-LEVEL TROUGH. JET SUPPORT ALSO LOOKS TO HAVE
SHIFTED FARTHER SOUTH COMPARED TO RECENT RUNS. K INDICES ARE HIGHEST
TOWARD THE COAST LATE TONIGHT AND MONDAY MORNING...BUT 850MB THETA-E
STILL REMAINS MODEST WEST THROUGH THE COASTAL PLAIN...AND WITH THE
WEAK LIFT AS LOW PRESSURE ORGANIZES JUST OFFSHORE...WILL CONTINUE AT
LEAST A CHANCE OF RAIN EARLY TONIGHT MAINLY EAST OF INTERSTATE 95
WHEN OVERALL MOISTURE APPEARS HIGHEST FOR THE NIGHTTIME HOURS...
THEN AGAIN MAINLY MONDAY MORNING ALONG AND EAST OF ABOUT U.S. 1
DURING A PERIOD OF A MODEST INCREASE IN MID-LEVEL MOISTURE IN
CONJUNCTION WITH GOOD LOWER-LEVEL MOISTURE. FOR NOW WILL KEEP
CHANCES BELOW LIKELY GIVEN THE DRIER MODEL TRENDS...NO MOS GUIDANCE
IN CENTRAL NORTH CAROLINA CLOSE TO LIKELY...AND NAM AND GFS MODEL
QPF BEING PRETTY LOW. PLAN TO KEEP THE TRIAD AND THE FAR WESTERN
PIEDMONT DRY THIS PERIOD.
850MB THETA-E TROUGHINESS STARTS TO PUSH EAST MONDAY AFTERNOON WITH
INCREASING SUBSIDENCE. BUFR SOUNDINGS ARE FAIRLY STABLE AND DRYING
CERTAINLY BY 00Z TUESDAY...AND PRECIPITABLE WATER VALUES ARE AT OR
BELOW A HALF-INCH MONDAY NIGHT. WILL NOTE CHANCES BELOW SLIGHT IN
CENTRAL NORTH CAROLINA BY 00Z TUESDAY. LOWS TONIGHT AND HIGHS MONDAY
ARE A LITTLE TRICKY GIVEN THE UNCERTAINTY SURROUNDING CLOUD COVER
AND THE POTENTIAL VARIABLE THICKNESS OF SUCH CLOUD COVER. OPTED TO
TRIM LOWS TONIGHT SLIGHTLY ESPECIALLY ALONG AND NORTH OF INTERSTATE
85 WHERE CLOUD COVER SHOULD BE LEAST AND THINNEST OVERNIGHT. GIVEN
THE DRIER MODEL TREND OPTED TO RAISE MAXES INTO THE 50S THROUGHOUT
CENTRAL NORTH CAROLINA MONDAY...STILL KEEPING THE WARMER READINGS
OVER THE WESTERN PIEDMONT FOR NOW. OVERNIGHT LOWS MONDAY NIGHT NEAR
THE COOLER MAV MOS GUIDANCE ANTICIPATING FEWER CLOUDS...LOWER TO MID
30S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
WEAK HIGH PRESSURE WILL BUILD INTO THE REGION ON TUESDAY IN THE WAKE
OF THE DEPARTING COASTAL CYCLONE AS A WESTERLY FLOW DEVELOPS ALOFT.
FAIR WEATHER IS EXPECTED IN CENTRAL NC WITH A FEW LAYERS OF CLOUDS.
HIGHS WILL RANGE IN THE LOWER 50S NORTHEAST TO NEAR 60 TOWARD THE SC
BORDER.
HEIGHTS BEGIN RISING ON WEDNESDAY AND THURSDAY AS A BROAD TROUGH
DEVELOPS IN THE ROCKIES AND THE NORTHERN PLAINS. AN INCREASINGLY
MOIST SOUTHERLY FLOW WILL PROMOTE AN INCREASE IN CLOUDINESS ON
WEDNESDAY AND THURSDAY WITH WARMING TEMPERATURES ESPECIALLY ON
THURSDAY. BOTH THE EC EFS AND THE GFS HIGHLIGHT A SHALLOW
DISTURBANCE THAT WILL MOVE NORTHEAST ACROSS THE AREA ON WEDNESDAY
THAT SHOWS UP AS A REGION OF ISENTROPIC UPGLIDE IN THE 290-295
LAYER. DON`T EXPECT ANY PRECIPITATION AT THIS TIME BUT HAVE
INCREASED CLOUD PERCENTAGES DURING THE PERIOD. GFS BUFR SOUNDINGS
ALSO SUGGEST THAT THERE COULD BE SOME GUSTY WINDS ON WEDNESDAY
AFTERNOON WITH GUSTS UP TO 20-25 MPH AS MIXING TAPS INTO THE
STRONGER FLOW ASSOCIATED WITH THE LOW LEVEL JET. A SLIGHTLY BETTER
CHANCE OF RAIN ARRIVES IN THE NORTHWESTERN PORTION OF THE FORECAST
AREA LATE THURSDAY AND ESPECIALLY THURSDAY NIGHT AS A COLD FRONT
APPROACHES THE REGION FROM THE WEST. TEMPERATURES SHOULD WARM INTO
THE MID 50S TO NEAR 60 ON ON WEDNESDAY AND THEN THE 60S TO NEAR 70
ON THURSDAY.
DIFFERENCES IN THE GFS AND EC EFS BECOME MORE APPARENT ON FRIDAY AND
ESPECIALLY SATURDAY WITH THE GFS BEING FASTER AND PUSHING THE FRONT
THROUGH THE AREA LATE FRI/EARLY SAT WITH THE EC PERHAPS 12 HOURS
SLOWER. WHILE THE BEST FORCING FOR ASCENT STAYS NORTH OF THE
AREA...THE PLUME OF DEEP LAYER MOISTURE AND FORCING ASSOCIATED WITH
THE FRONT SHOULD BE SUFFICIENT FOR CHC POPS. MILD TEMPERATURES ARE
EXPECTED ON FRIDAY AHEAD OF THE FRONT AND AHEAD OF THE MAIN AREA OF
RAIN. MAX TEMPS HAVE BEEN ADJUSTED UPWARD INTO THE UPPER 60S
NORTHWEST TO NEAR 75 IN THE SOUTHEAST. ALSO ADJUSTED MIN TEMPS ON
SATURDAY UPWARD TO ACCOUNT FOR THE CLOUDS AND MILD CONDITIONS AHEAD
OF THE FRONT. MAX TEMPS ON SATURDAY WILL BE LIMITED GIVEN THE CLOUDS
AND AREAS OF LIGHT RAIN BUT STILL EXPECT TEMPS TO REACH THE UPPER
50S NORTHWEST TO MID 60S SOUTHEAST. AT THIS POINT WE DON`T EXPECT
ANY THUNDERSTORMS LATE FRIDAY INTO SATURDAY THUNDERSTORMS GIVEN THE
MARGINAL MID LEVEL LAPSE RATES.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 1255 AM SUNDAY...
MOSTLY VFR CONDITIONS WILL CONTINUE THROUGH THE 06Z VALID TAF
PERIOD. AREAS OF MVFR CONDITIONS WILL OCCUR TOWARD KFAY AND KRWI
THIS MORNING...WITH PATCHY MVFR CONDITIONS IN EITHER LOW CLOUDS OR
LIGHT FOG TOWARD KRDU. MAINLY DURING THE AFTERNOON AND EVENING
PATCHY LIGHT RAIN IS POSSIBLE SOUTH OF A LINE FROM ABOUT KFAY TO
KRWI. THIS IS WHERE ANY THICKER CLOUDS SHOULD RESIDE DURING THAT
TIME...THOUGH THEY ARE EXPECTED CURRENTLY TO HAVE A HIGHER
PROBABILITY OF BEING VFR. WITH HIGH PRESSURE OVERHEAD...WINDS SHOULD
BE SOMEWHAT VARIABLE. JUST ON THE WEST SIDE OF THE SURFACE RIDGE
AXIS...WINDS SHOULD BE MORE SOUTHWEST TOWARD THE TRIAD. WINDS SHOULD
TEND TO FAVOR NORTHERLY TOWARD KFAY. AT KRWI AND ESPECIALLY KRDU...
THE LIGHT SURFACE WIND DIRECTION IS MORE CHALLENGING...LEANING
WESTERLY DURING THE DAYLIGHT HOURS THOUGH IT COULD BE QUITE VARIABLE.
BEYOND THE 06Z VALID TAF PERIOD...THE GREATEST PROBABILITY OF SUB-
VFR CONDITIONS OVERNIGHT INTO MONDAY MORNING IN CLOUDS AND PATCHY
LIGHT RAIN WILL BE ALONG AND EAST OF INTERSTATE 95...LEANING MVFR AS
A CATEGORY...WITH A CHANCE OF SUB-VFR CONDITIONS IN LIGHT FOG TOWARD
THE TRIAD. KRDU WILL BE IN BETWEEN...AND IT IS POSSIBLE FOR A PERIOD
OF BOTH LIGHT FOG AND LOWER CLOUDS THERE BEFORE DRIER AIR AND
SUBSIDENCE MOVING IN FROM THE WEST CREATE WIDESPREAD VFR CONDITIONS
ACROSS CENTRAL NORTH CAROLINA BY LATE MONDAY AFTERNOON. MVFR
CONDITIONS IN FOG ARE POSSIBLE LATE MONDAY NIGHT AND EARLY
TUESDAY...THEN AS MOISTURE INCREASES...THERE IS A CHANCE OF SUB-VFR
CONDITIONS IN LOW CLOUDS TUESDAY NIGHT INTO WEDNESDAY...WITH GREATER
CHANCES OF THOSE CONDITIONS CURRENTLY TOWARD THE TRIAD THOUGH
POSSIBLE THROUGHOUT CENTRAL NORTH CAROLINA PARTICULARLY WEDNESDAY
NIGHT.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...BLAES
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
928 PM CST MON DEC 2 2013
.UPDATE...
ISSUED AT 927 PM CST MON DEC 2 2013
THE FOCUS FOR THE 10 PM UPDATE WILL BE THE ISSUANCE OF A WINTER
STORM WARNING FOR THE SOUTHEAST...MAINLY SOUTHERN BELTRAMI THROUGH
WADENA COUNTY AND EASTERN PORTIONS OF BECKER...CLEARWATER...AND
OTTER TAIL.
STORM TOTALS AT THE BEGINNING OF EVENING SHIFT WERE AROUND 5 TO 6
INCHES AND RADAR TRENDS AND THE LATEST RAP GUIDANCE INDICATED THE
EVENT SHOULD END AROUND 11 PM. HRRR WAS A BIT SLOWER...PULLING
PRECIP OUT AROUND 1 AM. HOWEVER...WITH RADAR COVERAGE EXTREMELY
POOR IN THIS AREA DUE TO DISTANCE/OVERSHOOTING ISSUES...HAVE HAD
TO MAKE A PLETHORA OF CALLS IN THE AREA. WE ARE NOW RECEIVING
REPORTS IN THE 6 TO 8 INCH RANGE WITH AN ISOLATED REPORT AROUND 9.
REPORTS FROM THE WADENA AREA INDICATE THE SNOW IS STILL COMING
DOWN AT A DECENT RATE OF AN INCH PER HOUR. AFTER COORDINATION WITH
DLH OFFICE...WILL BE ISSUING A WINTER STORM WARNING FOR THE AREA.
TOTAL ACCUMULATION MAY GET TO THE 8 TO 10 INCH RANGE WITH ISOLATED
AMOUNTS SLIGHTLY HIGHER. THE NAM IS INDICATING A NARROW BAND OF
INCREASED 280K ISENTROPIC LIFT OVER THE AREA. WARNING WILL BE IN
EFFECT UNTIL 12Z.
IT IS VERY IMPORTANT TO REALIZE THE WARNING IS PART OF THE FIRST
WAVE OF SNOW THAT HAS BEEN ADVERTISED...AND WILL BE FOLLOWED BY A
WINTER STORM WATCH FOR THE SECOND WAVE THAT WILL IMPACT THE AREA
FROM MID DAY TUESDAY THROUGH MUCH OF THE DAY WEDNESDAY. ONLY MINOR
UPDATES TO THE GRIDS FOR THE 2ND WAVE...ALTHOUGH HAVE EXPANDED THE
AREA OF LOWER POPS FOR THE LULL IN ACTIVITY EXPECTED ACROSS THE
SOUTH FOR THE REMAINDER OF TONIGHT THROUGH MID DAY TUESDAY.
UPDATE ISSUED AT 648 PM CST MON DEC 2 2013
FOCUS FOR EVENING UPDATE WILL BE TO EXTEND FAR SOUTHERN ZONES
(RANSOM/SARGENT THROUGH GRANT) WINTER WEATHER ADVISORY THROUGH 12Z
TO MATCH REST OF HEADLINES. AREA WAS SET TO EXPIRE AT
00Z...HOWEVER WEAK ECHOES MOVING INTO REGION AS WELL AS SOUNDINGS
INDICATING POSSIBILITY OF SOME FREEZING DRIZZLE...WOULD PREFER TO
EXTEND IN TIME WITH WEATHER OVER THE REGION CONTINUING. SNOWFALL
CONTINUES MAINLY ALONG AND NORTH OF I 94 CORRIDOR WITH SOME SITES
NOW REPORTING SIX INCHES (BJI AND PKD). CHECKING NOW TO SEE HOW
WIDESPREAD THE SIX INCH REPORTS ARE TO DETERMINE IF HEADLINES
SHOULD BE UPDATED. MORE DIFFICULT TO DETERMINE IN THIS AREA AS
RADAR OVERSHOOTS SNOW IN THE BJI AREA...SO MAINLY WILL GO OFF WEB
CAMS AND PUBLIC REPORTS. STAY TUNED FOR MORE INFO IN THIS REGION.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 321 PM CST MON DEC 2 2013
PRECIP TYPE...SNOW AMOUNTS AND WHAT TO DO WITH HEADLINES CONTINUE
TO BE THE PRIMARY FORECAST HEADACHES FOR THE PERIOD.
MAIN UPPER LOW IS STILL DIGGING INTO THE PAC NW THIS
AFTERNOON...WITH ONLY PARTIAL RAOB SAMPLING FOR THE INITIALIZATION
OF THE 12Z MODEL RUNS THIS MORNING. MODEL CONSISTENCY HAS
CONTINUED TO BE POOR EVEN IN THE FIRST 24 HOURS OF THE RUNS. SNOW
BAND FROM THE LEAD SHORTWAVE TODAY HAS BROUGHT 3 TO 6 INCHES OF
ACCUMULATION FROM WEST OF FARGO TO NEAR ALEX. HOWEVER...THE BAND
HAS BEEN WEAKENING AS IT MOVES NORTHEASTWARD. THINK THAT SNOW
ACCUMULATIONS NORTH OF THE I-94 CORRIDOR WILL BE FAIRLY LIGHT AND
MAY ONLY BE AN INCH OR TWO. HOWEVER...THERE IS STILL A LOT OF
SLICK ROADS AND SOME OF THE MODELS SOUNDINGS ACROSS THE SOUTHERN
COUNTIES SHOW THE POSSIBILITY OF SOME FREEZING DRIZZLE. WILL
CONTINUE TO KEEP THE WINTER WEATHER ADVISORY GOING OVERNIGHT.
FOR TOMORROW...THE MODELS SHOW THE FIRST UPPER SHORTWAVE EJECTING
NORTHEASTWARD INTO THE DAKOTAS TUESDAY WHILE THE NEXT SHORTWAVE
DIGS FURTHER SOUTH AND DOES NOT MOVE EASTWARD UNTIL MID WEEK.
THERE IS STILL DISAGREEMENT ON THE EXACT TRACK OF THE SFC
LOW. ALL START IT OFF AS AN INVERTED TROUGH OVER SOUTHERN
MN...WITH A DECENT PRECIP BAND OVER THE CWA AND WINDS STARTING TO
PICK UP. HOWEVER...WHEN THE MODELS CLOSE THE LOW OFF AND HOW FAR
WEST REMAINS IN QUESTION. THE ECMWF HAS TRENDED FARTHER SOUTH WITH
THE HEAVY SNOW BAND WITH EACH RUN...AND THE GFS AND 12Z NAM ALSO
SEEM TO BE FARTHER SOUTH...ALTHOUGH THE 18Z NAM HAS GONE BACK THE
OTHER DIRECTION. EVEN WITH THE FURTHER NORTH SOLUTION...THE CWA
WILL BE IN A LULL BETWEEN TODAYS LEAD SHORTWAVE AND THE NEXT VORT
MAX...SO CONDITIONS MAY NOT BE TOO BAD WHEN PEOPLE GET UP IN THE
MORNING. WITH THIS AND ALL THE UNCERTAINTY OF US EVEN GETTING 6
INCHES...WILL MAINTAIN THE WATCH AND HOLD OFF ON ANY UPGRADES FOR
NOW.
TUESDAYS SHORTWAVE WILL MOVE OFF INTO WI TUESDAY NIGHT...WITH SFC
LOW DEEPENING. THE PRESSURE GRADIENT WILL BE PICKING UP AS THE
ARCTIC HIGH DIGS INTO THE NORTHERN ROCKIES. WINDS WILL BE VERY
STRONG LATE TUESDAY INTO TUESDAY NIGHT...AND BLOWING AND DRIFTING
SNOW COULD BE A PROBLEM. WILL CONTINUE TO MAKE MENTION OF THIS IN
THE WSW AND GRIDS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 321 PM CST MON DEC 2 2013
WEDNESDAY...AN UPPER TROUGH WILL CONTINUE OVER THE ROCKIES...WITH
ANOTHER WEAK SHORTWAVE EJECTING INTO THE PLAINS. WILL CONTINUE TO
KEEP HIGH POPS GOING AND STRONG WINDS...AND THE WATCH WILL REMAIN
THROUGH THE PERIOD. THE SFC LOW WILL MOVE OFF TO THE EAST...WITH
THE ARCTIC AIR COMING IN BEHIND IT. TEMPS MAY NOT GET OUT OF THE
SINGLE DIGITS IN THE NORTHWESTERN COUNTIES AND WITH WINDS
CONTINUING THE CHILL FACTOR WILL BE BRUTAL.
FOR WEDNESDAY NIGHT INTO THURSDAY THERE ARE STILL ENOUGH MODEL
DIFFERENCES TO KEEP A LOT OF UNCERTAINTY IN THE FORECAST. THE 12Z
ECMWF STILL HAS A PRETTY DECENT PRESSURE GRADIENT OVER THE FA WHILE
THE 12Z GFS HAS MUCH LESS. FOR NOW WILL KEEP THINGS MIDDLE OF THE
ROAD WITH SOME GUSTINESS LINGERING WED NIGHT AND THEN DIMINISHING
THINGS ON THU. COLDER AIR WILL CONTINUE TO MOVE INTO THE FA WITH
TEMPS HINGING ON CLOUD COVER. RIGHT NOW IT APPEARS LIKE A GOOD
AMOUNT OF CLOUD COVER WILL HOLD OVER THE AREA KEEPING THE REALLY
COLD TEMPS AT BAY. HOWEVER DETERMINING CLOUD AMOUNTS WITH GOOD
ACCURACY THIS FAR OUT IS TOUGH.
BY THU NIGHT INTO MONDAY CLOUD TRENDS AND TEMPS WILL BE THE MAIN
ISSUE. MODELS SEEM TO LINGER SNOW SHOWERS IN THE NORTHEAST FA A LONG
TIME OR GENERALLY FROM THU NIGHT THRU SAT NIGHT. MEANWHILE 850MB
TEMPS DROP WELL INTO THE 20S BELOW ZERO. SFC HIGH PRESSURE WILL TRY
TO BUILD INTO THE FA BY SATURDAY BUT UNTIL THEN THE 12Z ECMWF KEEPS
SUSTAINED WIND SPEEDS ABOVE 10KTS. THEREFORE IT WILL BE HARD TO
REALIZE THE FULL POTENTIAL OF THE COLD AIR. THE HIGH PRESSURE SYSTEM
IS EXPECTED TO SLIDE TO THE EAST SAT NIGHT AS ANOTHER WEAKER SYSTEM
MOVES UP INTO THE FA FROM THE SOUTHWEST. THIS NEXT SYSTEM LOOKS
WEAKER SO SNOW AMOUNTS SHOULD STAY ON THE LIGHTER SIDE. THIS SYSTEM
WOULD ALSO SPREAD MORE CLOUD COVER INTO THE REGION WHICH WOULD
CONTINUE TO MODERATE THE FRIGID AIR OVER THE FA. HOWEVER COLD IS
COLD AND CLOUDS WOULD NOT MODERATE THINGS THAT MUCH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 640 PM CST MON DEC 2 2013
WOULD EXPECT PREDOMINANTLY MVFR CIGS LOWERING TO IFR CIGS THIS
EVENING HOWEVER THERE WILL BE SOME POCKETS OF SHORT LIVED VFR
CONDS TONIGHT. GFK LATEST OB CONTINUES TO SHOW VFR CIGS WITH MVFR
ELSEWHERE SO WILL NOT MENTION VFR IN TAFS. ALSO WILL SEE LIGHT
SNOW WTIH SOME REDUCED VSBYS OVER BJI THIS EVENING UNDER SOME
HEAVIER SNOW SHOWERS. CONDS WILL CONTINUE THROUGH THE TAF PERIODS
AS A SECOND WAVE OF SNOW MOVES INTO REGION TOMORROW.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR NDZ006>008-
014>016-024-026>030-038-039-049-052>054.
WINTER STORM WATCH FROM 6 AM CST TUESDAY THROUGH WEDNESDAY
AFTERNOON FOR NDZ006>008-014>016-024-026>030-038-039-049-
052>054.
MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR MNZ001>009-
013>015-022-027-029-030-040.
WINTER STORM WATCH FROM 6 AM CST TUESDAY THROUGH WEDNESDAY
AFTERNOON FOR MNZ001>009-013>017-022>024-027>032-040.
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR MNZ016-017-023-
024-028-031-032.
&&
$$
UPDATE...SPEICHER
SHORT TERM...JR
LONG TERM...JR/GODON
AVIATION...SPEICHER
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
107 PM CST SUN DEC 1 2013
.UPDATE...
ISSUED AT 107 PM CST SUN DEC 1 2013
CANCELLED DENSE FOG ADVISORY AS VISIBILITY HAS RISEN ABOVE 1/2 MILE
AT ALL OBSERVATION SITES EXCEPT A COUPLE (VALLEY CITY/LANGDON).
THERE STILL MAY BE A FEW SPOTS WITH DENSE FOG THROUGH THE
AFTERNOON...BUT IT IS NO LONGER WIDESPREAD ENOUGH TO JUSTIFY AN
ADVISORY. MOTORISTS SHOULD STILL BE PREPARED FOR RAPIDLY CHANGING
DRIVING CONDITIONS...ESPECIALLY AROUND FAVORED LOW SPOTS FOR FOG
FORMATION. LOW CLOUDS ARE REALLY TAKING A BITE OUT OF TEMPERATURES...
SO DROPPED AFTERNOON HIGHS A HANDFUL OF DEGREES. BAND OF LIGHT
SNOW HAS MOVED INTO AREAS WEST OF THE VALLEY AND THIS IS HANDLED
WELL BY CURRENT POPS. REST OF THE FORECAST OK WITH NO OTHER
CHANGES AT THIS TIME.
UPDATE ISSUED AT 1015 AM CST SUN DEC 1 2013
CONCERNS THIS MORNING INCLUDE FOG AND LIGHT SNOW.
DENSE FOG DEVELOPED ACROSS AREAS WEST OF THE VALLEY FROM LANGDON
TO COOPERSTOWN TO GWINNER BETWEEN 7 AND 8 AM CST AND HAS
MAINTAINED ITSELF FOR MUCH OF THE MORNING. LATEST RAP/HRRR
GUIDANCE SUGGESTS POCKETS OF DENSE FOG WILL CONTINUE THROUGH LATE
MORNING AND INTO THE AFTERNOON AND WITH NO REAL CHANGE IN AIR MASS
AND/OR LOW LEVEL WIND FIELD...WILL ISSUE A DENSE FOG ADVISORY FOR
WESTERN TIER COUNTIES UNTIL 21 UTC. MAY VERY WELL BE ABLE TO
CANCEL IT EARLY...BUT VISIBILITIES AT OR BELOW 1/4 SM ARE
WIDESPREAD ENOUGH TO WARRANT ISSUANCE.
ALSO INCREASED POPS A BIT FARTHER EAST ACROSS EASTERN ND THROUGH
THE DAY WITH A NARROW BAND OF LIGHT SNOW JUST ENTERING THE DEVILS
LAKE BASIN. RAP SOUNDING AT KDVL SUGGESTS THERE MAY BE SOME
FREEZING DRIZZLE MIXED IN...BUT UPSTREAM OBSERVATIONS THUS FAR
HAVE BEEN ALL SNOW. PRIMARY MID-LEVEL WARM AIR ADVECTION SNOW
STILL STRETCHES FROM KENMARE TO GARRISON AND WILL IMPACT THE
REGION LATER THIS AFTERNOON AND EVENING. ALSO INTRODUCED SOME 20
POPS ACROSS THE LAKE OF THE WOODS REGION LATE THIS MORNING FOR
SOME LIGHT SNOW BEING REPORTED AT ROSEAU...BAUDETTE AND WASKISH.
TEMPERATURE/SKY/WIND GRIDS ARE IN GOOD SHAPE WITH NO MAJOR CHANGES
AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 418 AM CST SUN DEC 1 2013
00Z/06Z MODELS ARE COMING MORE IN LINE TOWARD A GENERAL CONSENSUS
SOLUTION...WITH THE GFS REMAINING A FAST OUTLIER. EVEN THE NAM IS
SIMILAR TO THE CONSENSUS...JUST STRONGER. THE IDEA IS THAT AN
UPPER LOW WILL DIG INTO THE NORTHWEST CONUS/NORTHERN
ROCKIES...THEN EJECT INTO NORTHERN MINNESOTA BY 12Z WED. MODELS
HAVE REMAINED CONSISTENT INDICATING 3 ROUNDS OF SNOWFALL.
THE FIRST ROUND WILL BE LATER THIS AFTERNOON INTO TONIGHT.
FORCING IS WEAK AND AVAILABLE MOISTURE IS RELATIVELY
LOW...THINKING UP TO AN INCH OF SNOWFALL IS MOST LIKELY.
THE SECOND WAVE (MONDAY INTO MONDAY NIGHT) IS STRONGER...WITH MORE
AVAILABLE MOISTURE (PWATS APPROACHING 0.5 INCHES). MODELS INDICATE
A DEFINED CIRCULATION AT 850MB (AND A WEAK 700MB LOW) PROPAGATING
FROM NW ND INTO WESTERN MN ON MONDAY...LOSING DEFINITION MONDAY
NIGHT AS IT PROPAGATES FURTHER TO THE EAST. ASSOCIATED WARM AIR
ADVECTION/FRONTOGENESIS COMBINED WITH THE 0.5 INCH PWATS SHOULD
LEAD TO A BAND OF SNOWFALL MOVING THROUGH THE REGION. MODELS
INDICATE 0.20-0.40 INCHES QPF ACROSS ALL BUT THE NE FA...AND
COMBINED WITH 12:1-13:1 SNOW RATIOS WOULD LEAD TO AN AREA OF 2-5
INCHES OF SNOW. MODELS INDICATE THAT THE MESOSCALE FORCING IS
RELATIVELY WEAK...WHICH WOULD MEAN THE MODELS SHOULD BE IN THE
BALL PARK WITH QPF.
THE THIRD ROUND OF SNOWFALL (TUESDAY-TUESDAY NIGHT) WILL BE
ASSOCIATED WITH THE MAIN STRONG MID-LEVEL LOW MOVING THROUGH THE
REGION. THE 00Z ECMWF IS SLIGHTLY FASTER WITH THIS FEATURE.
SYNOPTIC FORCING WILL BE VERY STRONG...WITH THE POTENTIAL FOR
MESOSCALE BANDING. WITH THAT SAID...THIS ROUND OF SNOWFALL STILL
HAS THE MOST UNCERTAINTY (DUE TO MODEL DIFFERENCES). GIVEN THE
AVAILABLE MOISTURE (PWATS 0.5+ INCHES) AND STRONG FORCING
EXPECTED...ALONG WITH THE SLOW MOVING NATURE OF THE SYSTEM...THIS
ROUND SHOULD BRING 6+ INCHES (CURRENT THOUGHTS ARE 5 TO 10 INCHES)
TO MOST AREAS. SOMETIME TOWARD THE TAIL END OF THE
SNOWFALL...WINDS SHOULD INCREASE...LIKELY STRONG ENOUGH FOR
BLOWING SNOW ISSUES.
SINCE THE TRUE WINTER WARNING CONDITIONS WILL LIKELY NOT OCCUR
UNTIL SOMETIME ON TUESDAY...WILL HOLD OFF ON ISSUING ANY
WINTER HEADLINES. THIS WILL ALLOW FOR ANOTHER SET OF MODEL RUNS TO
INCREASE CONFIDENCE. COULD SEE A SITUATION WHERE WE HAVE ADVISORY
CONDITIONS ON MONDAY/MONDAY NIGHT FOLLOWED BY A SHORT BREAK...THEN
WARNING CRITERIA SNOW TUESDAY/TUESDAY NIGHT (WITH WINDS AND
BLOWING SNOW LATER TUESDAY NIGHT INTO WEDNESDAY). WILL ADD SOME
DETAIL TO THE SPECIAL WEATHER STATEMENT AND HWO.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 418 AM CST SUN DEC 1 2013
WEDNESDAY-SATURDAY...BOTH THE GFS/ECMWF INDICATE SNOW WINDING
DOWN ON WEDNESDAY AS THE SFC LOW PULLS AWAY. DESPITE A TREND
TOWARDS A FASTER SOLUTION...THERE IS STILL SOME UNCERTAINTY WITH
THE 00Z GEM SLOWER WITH THE SFC LOW...KEEPING SNOW AROUND THROUGH
WEDNESDAY NIGHT. SOME LIGHT SNOW/SNOW SHOWERS COULD LINGER INTO
LATE WEEK AS A REINFORCING UPPER LOW PIVOTS SOUTHWARD INTO THE
REGION...MAINTAINING CYCLONIC FLOW. HOWEVER...THE MAIN CONCERN FOR
THE REMAINDER OF THE WEEK WILL BE TEMPS AS A BITTERLY COLD ARCTIC
AIR MASS TAKES UP RESIDENCE ACROSS THE NORTHERN PLAINS. BASED ON A
MORE PROGRESSIVE SOLUTION...STRONG LOW-LEVEL COLD ADVECTION MAY
PREVENT MUCH TEMPERATURE RISE ON WEDNESDAY. 1000-500 MB
THICKNESSES FALL BELOW 500 DAM BY THURSDAY/FRIDAY...WITH HIGHS NO
HIGHER THAN THE LOW SINGLE DIGITS. MODELS INDICATE THE SFC HIGH
AXIS DOES NOT APPROACH UNTIL NEXT WEEKEND. THUS...WITH ONLY A
GRADUAL SLACKENING OF THE PRESSURE GRADIENT...WINDS WILL REMAIN UP
A BIT THROUGH THE WORK WEEK. THE COMBINATION OF WINDS AND BITTERLY
COLD TEMPS LIKELY WILL LEAD TO DANGEROUS WIND CHILLS AT TIMES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 107 PM CST SUN DEC 1 2013
IFR AND LOWER CIGS WILL CONTINUE THROUGH THE EARLY AFTERNOON. SAT
LOOP SHOWS SOME CLEARING ON THE BACK SIDE OF THE TROUGH AXIS IN
WESTERN ND...BUT MODELS ALL HAVE THE SFC TROUGH STARTING TO WASH
OUT...WITH THE WESTERLY WINDS NEVER REACHING OUR FORECAST AREA.
THINK THAT THE STRATUS WILL CONTINUE THROUGH THE REST OF THE
DAY...POSSIBLY LIFTING TO MVFR LEVELS FOR A BRIEF PERIOD. CONDITIONS
WILL DETERIORATE AGAIN THIS EVENING AS CIGS DROP BACK DOWN BELOW
1000 FT AND A BAND OF LIGHT SNOW MOVES IN. THE SNOW WILL BE BRIEF
AND ONLY AFFECT TAF SITES FOR A FEW HOURS WITH VIS AROUND 2SM OR SO.
HOWEVER...AFTER THE SNOW MOVES OFF TO THE EAST THE LOW CIGS AND SOME
MIST WILL CONTINUE. THERE WILL BE ANOTHER...HEAVIER BAND OF SNOW
BEGINNING TO MOVE INTO THE FORECAST AREA LATE IN THE PERIOD. THE
BAND COULD BE AS FAR EAST AS KFAR AND KGFK BY 18Z...BUT FOR NOW WILL
JUST INCLUDE A MENTION AT KDVL.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...TG
LONG TERM...MAKOWSKI
AVIATION...JR
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1015 AM CST SUN DEC 1 2013
.UPDATE...
ISSUED AT 1015 AM CST SUN DEC 1 2013
CONCERNS THIS MORNING INCLUDE FOG AND LIGHT SNOW.
DENSE FOG DEVELOPED ACROSS AREAS WEST OF THE VALLEY FROM LANGDON
TO COOPERSTOWN TO GWINNER BETWEEN 7 AND 8 AM CST AND HAS
MAINTAINED ITSELF FOR MUCH OF THE MORNING. LATEST RAP/HRRR
GUIDANCE SUGGESTS POCKETS OF DENSE FOG WILL CONTINUE THROUGH LATE
MORNING AND INTO THE AFTERNOON AND WITH NO REAL CHANGE IN AIR MASS
AND/OR LOW LEVEL WIND FIELD...WILL ISSUE A DENSE FOG ADVISORY FOR
WESTERN TIER COUNTIES UNTIL 21 UTC. MAY VERY WELL BE ABLE TO
CANCEL IT EARLY...BUT VISIBILITIES AT OR BELOW 1/4 SM ARE
WIDESPREAD ENOUGH TO WARRANT ISSUANCE.
ALSO INCREASED POPS A BIT FARTHER EAST ACROSS EASTERN ND THROUGH
THE DAY WITH A NARROW BAND OF LIGHT SNOW JUST ENTERING THE DEVILS
LAKE BASIN. RAP SOUNDING AT KDVL SUGGESTS THERE MAY BE SOME
FREEZING DRIZZLE MIXED IN...BUT UPSTREAM OBSERVATIONS THUS FAR
HAVE BEEN ALL SNOW. PRIMARY MID-LEVEL WARM AIR ADVECTION SNOW
STILL STRETCHES FROM KENMARE TO GARRISON AND WILL IMPACT THE
REGION LATER THIS AFTERNOON AND EVENING. ALSO INTRODUCED SOME 20
POPS ACROSS THE LAKE OF THE WOODS REGION LATE THIS MORNING FOR
SOME LIGHT SNOW BEING REPORTED AT ROSEAU...BAUDETTE AND WASKISH.
TEMPERATURE/SKY/WIND GRIDS ARE IN GOOD SHAPE WITH NO MAJOR CHANGES
AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 418 AM CST SUN DEC 1 2013
00Z/06Z MODELS ARE COMING MORE IN LINE TOWARD A GENERAL CONSENSUS
SOLUTION...WITH THE GFS REMAINING A FAST OUTLIER. EVEN THE NAM IS
SIMILAR TO THE CONSENSUS...JUST STRONGER. THE IDEA IS THAT AN
UPPER LOW WILL DIG INTO THE NORTHWEST CONUS/NORTHERN
ROCKIES...THEN EJECT INTO NORTHERN MINNESOTA BY 12Z WED. MODELS
HAVE REMAINED CONSISTENT INDICATING 3 ROUNDS OF SNOWFALL.
THE FIRST ROUND WILL BE LATER THIS AFTERNOON INTO TONIGHT.
FORCING IS WEAK AND AVAILABLE MOISTURE IS RELATIVELY
LOW...THINKING UP TO AN INCH OF SNOWFALL IS MOST LIKELY.
THE SECOND WAVE (MONDAY INTO MONDAY NIGHT) IS STRONGER...WITH MORE
AVAILABLE MOISTURE (PWATS APPROACHING 0.5 INCHES). MODELS INDICATE
A DEFINED CIRCULATION AT 850MB (AND A WEAK 700MB LOW) PROPAGATING
FROM NW ND INTO WESTERN MN ON MONDAY...LOSING DEFINITION MONDAY
NIGHT AS IT PROPAGATES FURTHER TO THE EAST. ASSOCIATED WARM AIR
ADVECTION/FRONTOGENESIS COMBINED WITH THE 0.5 INCH PWATS SHOULD
LEAD TO A BAND OF SNOWFALL MOVING THROUGH THE REGION. MODELS
INDICATE 0.20-0.40 INCHES QPF ACROSS ALL BUT THE NE FA...AND
COMBINED WITH 12:1-13:1 SNOW RATIOS WOULD LEAD TO AN AREA OF 2-5
INCHES OF SNOW. MODELS INDICATE THAT THE MESOSCALE FORCING IS
RELATIVELY WEAK...WHICH WOULD MEAN THE MODELS SHOULD BE IN THE
BALL PARK WITH QPF.
THE THIRD ROUND OF SNOWFALL (TUESDAY-TUESDAY NIGHT) WILL BE
ASSOCIATED WITH THE MAIN STRONG MID-LEVEL LOW MOVING THROUGH THE
REGION. THE 00Z ECMWF IS SLIGHTLY FASTER WITH THIS FEATURE.
SYNOPTIC FORCING WILL BE VERY STRONG...WITH THE POTENTIAL FOR
MESOSCALE BANDING. WITH THAT SAID...THIS ROUND OF SNOWFALL STILL
HAS THE MOST UNCERTAINTY (DUE TO MODEL DIFFERENCES). GIVEN THE
AVAILABLE MOISTURE (PWATS 0.5+ INCHES) AND STRONG FORCING
EXPECTED...ALONG WITH THE SLOW MOVING NATURE OF THE SYSTEM...THIS
ROUND SHOULD BRING 6+ INCHES (CURRENT THOUGHTS ARE 5 TO 10 INCHES)
TO MOST AREAS. SOMETIME TOWARD THE TAIL END OF THE
SNOWFALL...WINDS SHOULD INCREASE...LIKELY STRONG ENOUGH FOR
BLOWING SNOW ISSUES.
SINCE THE TRUE WINTER WARNING CONDITIONS WILL LIKELY NOT OCCUR
UNTIL SOMETIME ON TUESDAY...WILL HOLD OFF ON ISSUING ANY
WINTER HEADLINES. THIS WILL ALLOW FOR ANOTHER SET OF MODEL RUNS TO
INCREASE CONFIDENCE. COULD SEE A SITUATION WHERE WE HAVE ADVISORY
CONDITIONS ON MONDAY/MONDAY NIGHT FOLLOWED BY A SHORT BREAK...THEN
WARNING CRITERIA SNOW TUESDAY/TUESDAY NIGHT (WITH WINDS AND
BLOWING SNOW LATER TUESDAY NIGHT INTO WEDNESDAY). WILL ADD SOME
DETAIL TO THE SPECIAL WEATHER STATEMENT AND HWO.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 418 AM CST SUN DEC 1 2013
WEDNESDAY-SATURDAY...BOTH THE GFS/ECMWF INDICATE SNOW WINDING
DOWN ON WEDNESDAY AS THE SFC LOW PULLS AWAY. DESPITE A TREND
TOWARDS A FASTER SOLUTION...THERE IS STILL SOME UNCERTAINTY WITH
THE 00Z GEM SLOWER WITH THE SFC LOW...KEEPING SNOW AROUND THROUGH
WEDNESDAY NIGHT. SOME LIGHT SNOW/SNOW SHOWERS COULD LINGER INTO
LATE WEEK AS A REINFORCING UPPER LOW PIVOTS SOUTHWARD INTO THE
REGION...MAINTAINING CYCLONIC FLOW. HOWEVER...THE MAIN CONCERN FOR
THE REMAINDER OF THE WEEK WILL BE TEMPS AS A BITTERLY COLD ARCTIC
AIR MASS TAKES UP RESIDENCE ACROSS THE NORTHERN PLAINS. BASED ON A
MORE PROGRESSIVE SOLUTION...STRONG LOW-LEVEL COLD ADVECTION MAY
PREVENT MUCH TEMPERATURE RISE ON WEDNESDAY. 1000-500 MB
THICKNESSES FALL BELOW 500 DAM BY THURSDAY/FRIDAY...WITH HIGHS NO
HIGHER THAN THE LOW SINGLE DIGITS. MODELS INDICATE THE SFC HIGH
AXIS DOES NOT APPROACH UNTIL NEXT WEEKEND. THUS...WITH ONLY A
GRADUAL SLACKENING OF THE PRESSURE GRADIENT...WINDS WILL REMAIN UP
A BIT THROUGH THE WORK WEEK. THE COMBINATION OF WINDS AND BITTERLY
COLD TEMPS LIKELY WILL LEAD TO DANGEROUS WIND CHILLS AT TIMES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 650 AM CST SUN DEC 1 2013
IFR CONDITIONS WILL LIKELY CONTINUE THROUGH THE MORNING
HOURS...GRADUALLY RISING WITH DAYTIME HEATING (BUT NOT GREATER
THAN MVFR CRITERIA). 10Z RAP GUIDANCE SHOWS THE POTENTIAL FOR A
PERIOD OF VFR CONDITIONS TONIGHT AS LOW LEVEL FLOW INCREASES. THIS
SEEMS LIKE A LOW PROBABILITY OF OCCURRENCE CONSIDERING THAT THE
LOW-LEVEL AIRMASS IS EXPECTED TO REMAIN SATURATED. WILL MONITOR
THE SITUATION AND ADJUST THE FORECASTS AS NEEDED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR NDZ006-007-
014-015-024-026-028-038-049-052.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...TG
LONG TERM...MAKOWSKI
AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
650 AM CST SUN DEC 1 2013
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 418 AM CST SUN DEC 1 2013
00Z/06Z MODELS ARE COMING MORE IN LINE TOWARD A GENERAL CONSENSUS
SOLUTION...WITH THE GFS REMAINING A FAST OUTLIER. EVEN THE NAM IS
SIMILAR TO THE CONSENSUS...JUST STRONGER. THE IDEA IS THAT AN
UPPER LOW WILL DIG INTO THE NORTHWEST CONUS/NORTHERN
ROCKIES...THEN EJECT INTO NORTHERN MINNESOTA BY 12Z WED. MODELS
HAVE REMAINED CONSISTENT INDICATING 3 ROUNDS OF SNOWFALL.
THE FIRST ROUND WILL BE LATER THIS AFTERNOON INTO TONIGHT.
FORCING IS WEAK AND AVAILABLE MOISTURE IS RELATIVELY
LOW...THINKING UP TO AN INCH OF SNOWFALL IS MOST LIKELY.
THE SECOND WAVE (MONDAY INTO MONDAY NIGHT) IS STRONGER...WITH MORE
AVAILABLE MOISTURE (PWATS APPROACHING 0.5 INCHES). MODELS INDICATE
A DEFINED CIRCULATION AT 850MB (AND A WEAK 700MB LOW) PROPAGATING
FROM NW ND INTO WESTERN MN ON MONDAY...LOSING DEFINITION MONDAY
NIGHT AS IT PROPAGATES FURTHER TO THE EAST. ASSOCIATED WARM AIR
ADVECTION/FRONTOGENESIS COMBINED WITH THE 0.5 INCH PWATS SHOULD
LEAD TO A BAND OF SNOWFALL MOVING THROUGH THE REGION. MODELS
INDICATE 0.20-0.40 INCHES QPF ACROSS ALL BUT THE NE FA...AND
COMBINED WITH 12:1-13:1 SNOW RATIOS WOULD LEAD TO AN AREA OF 2-5
INCHES OF SNOW. MODELS INDICATE THAT THE MESOSCALE FORCING IS
RELATIVELY WEAK...WHICH WOULD MEAN THE MODELS SHOULD BE IN THE
BALL PARK WITH QPF.
THE THIRD ROUND OF SNOWFALL (TUESDAY-TUESDAY NIGHT) WILL BE
ASSOCIATED WITH THE MAIN STRONG MID-LEVEL LOW MOVING THROUGH THE
REGION. THE 00Z ECMWF IS SLIGHTLY FASTER WITH THIS FEATURE.
SYNOPTIC FORCING WILL BE VERY STRONG...WITH THE POTENTIAL FOR
MESOSCALE BANDING. WITH THAT SAID...THIS ROUND OF SNOWFALL STILL
HAS THE MOST UNCERTAINTY (DUE TO MODEL DIFFERENCES). GIVEN THE
AVAILABLE MOISTURE (PWATS 0.5+ INCHES) AND STRONG FORCING
EXPECTED...ALONG WITH THE SLOW MOVING NATURE OF THE SYSTEM...THIS
ROUND SHOULD BRING 6+ INCHES (CURRENT THOUGHTS ARE 5 TO 10 INCHES)
TO MOST AREAS. SOMETIME TOWARD THE TAIL END OF THE
SNOWFALL...WINDS SHOULD INCREASE...LIKELY STRONG ENOUGH FOR
BLOWING SNOW ISSUES.
SINCE THE TRUE WINTER WARNING CONDITIONS WILL LIKELY NOT OCCUR
UNTIL SOMETIME ON TUESDAY...WILL HOLD OFF ON ISSUING ANY
WINTER HEADLINES. THIS WILL ALLOW FOR ANOTHER SET OF MODEL RUNS TO
INCREASE CONFIDENCE. COULD SEE A SITUATION WHERE WE HAVE ADVISORY
CONDITIONS ON MONDAY/MONDAY NIGHT FOLLOWED BY A SHORT BREAK...THEN
WARNING CRITERIA SNOW TUESDAY/TUESDAY NIGHT (WITH WINDS AND
BLOWING SNOW LATER TUESDAY NIGHT INTO WEDNESDAY). WILL ADD SOME
DETAIL TO THE SPECIAL WEATHER STATEMENT AND HWO.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 418 AM CST SUN DEC 1 2013
WEDNESDAY-SATURDAY...BOTH THE GFS/ECMWF INDICATE SNOW WINDING
DOWN ON WEDNESDAY AS THE SFC LOW PULLS AWAY. DESPITE A TREND
TOWARDS A FASTER SOLUTION...THERE IS STILL SOME UNCERTAINTY WITH
THE 00Z GEM SLOWER WITH THE SFC LOW...KEEPING SNOW AROUND THROUGH
WEDNESDAY NIGHT. SOME LIGHT SNOW/SNOW SHOWERS COULD LINGER INTO
LATE WEEK AS A REINFORCING UPPER LOW PIVOTS SOUTHWARD INTO THE
REGION...MAINTAINING CYCLONIC FLOW. HOWEVER...THE MAIN CONCERN FOR
THE REMAINDER OF THE WEEK WILL BE TEMPS AS A BITTERLY COLD ARCTIC
AIR MASS TAKES UP RESIDENCE ACROSS THE NORTHERN PLAINS. BASED ON A
MORE PROGRESSIVE SOLUTION...STRONG LOW-LEVEL COLD ADVECTION MAY
PREVENT MUCH TEMPERATURE RISE ON WEDNESDAY. 1000-500 MB
THICKNESSES FALL BELOW 500 DAM BY THURSDAY/FRIDAY...WITH HIGHS NO
HIGHER THAN THE LOW SINGLE DIGITS. MODELS INDICATE THE SFC HIGH
AXIS DOES NOT APPROACH UNTIL NEXT WEEKEND. THUS...WITH ONLY A
GRADUAL SLACKENING OF THE PRESSURE GRADIENT...WINDS WILL REMAIN UP
A BIT THROUGH THE WORK WEEK. THE COMBINATION OF WINDS AND BITTERLY
COLD TEMPS LIKELY WILL LEAD TO DANGEROUS WIND CHILLS AT TIMES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 650 AM CST SUN DEC 1 2013
IFR CONDITIONS WILL LIKELY CONTINUE THROUGH THE MORNING
HOURS...GRADUALLY RISING WITH DAYTIME HEATING (BUT NOT GREATER
THAN MVFR CRITERIA). 10Z RAP GUIDANCE SHOWS THE POTENTIAL FOR A
PERIOD OF VFR CONDITIONS TONIGHT AS LOW LEVEL FLOW INCREASES. THIS
SEEMS LIKE A LOW PROBABILITY OF OCCURRENCE CONSIDERING THAT THE
LOW-LEVEL AIRMASS IS EXPECTED TO REMAIN SATURATED. WILL MONITOR
THE SITUATION AND ADJUST THE FORECASTS AS NEEDED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...TG
LONG TERM...MAKOWSKI
AVIATION...TG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
419 PM EST SUN DEC 1 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE INTO THE AREA TONIGHT...STALLING AND
DISSIPATING LATE ON MONDAY. INCREASING SOUTHERLY FLOW WILL ALLOW
FOR WARMING TEMPERATURES AND GRADUAL INCREASES FOR PRECIPITATION
CHANCES...BEFORE A STRONGER COLD FRONT MOVES THROUGH THE AREA
LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
A WEAK FRONTAL BOUNDARY...EVIDENT MOST READILY WHEN LOOKING AT
SURFACE WINDS...IS CURRENTLY MOVING SOUTHWARD INTO OHIO. THERE IS
INCREASING LOW-LEVEL RH BEHIND THIS BOUNDARY...WITH A DRY AREA
CURRENTLY EXTENDING ACROSS MOST OF NORTHERN AND WESTERN OHIO AHEAD
OF IT. MEANWHILE...AN AREA OF THICK STRATOCUMULUS HAS BEEN VERY
GRADUALLY MOVING EAST ACROSS OHIO AND KENTUCKY TODAY. TIMING OUT
THE MOTIONS OF THESE DIFFERING RH LAYERS HAS BEEN A
CHALLENGE...WITH SEVERAL SCENARIOS IN THE MODELS AND WHAT SEEMS TO
BE A SLIGHT OVEREMPHASIS ON HIGHER RH VALUES. THE SLOW MOTION OF
THE CLOUDS COMING IN FROM THE NORTH LENDS ITSELF TO A PARTLY-
CLOUDY-AT-WORST FORECAST FOR MOST OF THE CWA (AT LEAST EARLY IN
THE OVERNIGHT...AND CERTAINLY NOT INCLUDING THE SOUTHEAST).
HOWEVER...CONFIDENCE DOES INCREASE THAT CLOUDS AND LOW-LEVEL RH
(PERHAPS VERY LOW) WILL BE IN PLACE BY MORNING. NAM AND RAP BUFKIT
SOUNDINGS SHOWED THE THICK MOISTURE CONFINED TO THE LOWEST 1000
FEET...THOUGH THE GFS APPEARED TOO AGGRESSIVE IN SATURATING
EVERYTHING UNDER 5KFT. THERE WAS EVEN SOME CONSIDERATION TO INCLUDING
DRIZZLE IN THE FORECAST...BUT LIFT IS NOT STRONG AND THE SOUTHWARD
EXTENT OF THE RH IS CERTAINLY IN QUESTION. DESPITE THE EXPECTED
CLOUDS...MIN TEMPS (ESPECIALLY IN THE NORTH) SHOULD AGAIN COOL TO
VALUES NEAR OR SLIGHTLY BELOW FREEZING...WITH MID TO UPPER 30S
ELSEWHERE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
ALTHOUGH NO SIGNIFICANT IMPACTS ARE EXPECTED DURING THE SHORT TERM
OF THE FORECAST...AND POPS ARE EXPECTED TO REMAIN IN THE CHANCE
RANGE OR LOWER...THE SPECIFIC DETAILS FOR PRECIPITATION AND CLOUDS
(IN TERMS OF AMOUNTS AND TIMING) ARE A LITTLE LOWER IN CONFIDENCE
THAN NORMAL.
THE BOUNDARY FORECAST TO MOVE INTO THE FORECAST AREA TONIGHT AND
INTO EARLY MONDAY MORNING WILL LOSE ITS DEFINITION...LEAVING THE
CWA IN A PATTERN OF VERY WEAK S-TO-SE FLOW. FLOW IN THE MID LEVELS
WILL BE QUASI-ZONAL...BUT WITH A SOMEWHAT-BROAD SHORTWAVE MOVING
INTO THE OHIO VALLEY ON MONDAY. THE OVERALL RESPONSE TO THIS
FEATURE IS NOT ESPECIALLY STRONG ON ALL MODELS BUT THE GFS (EVEN
ON BOTH THE 06Z AND 12Z RUNS). ALTHOUGH LOW LEVEL MOISTURE APPEARS
PREVALENT ON MOST MODELS...THE GFS IS BY FAR THE MOST ENHANCED
WITH DEEPER MOISTURE AND QPF RESPONSE. POPS FOR MONDAY AND INTO
MONDAY NIGHT HAVE BEEN SCALED BACK TO SLIGHT CHANCE...PUSHING
NORTH OF THE CWA BEFORE TUESDAY MORNING BEGINS.
AFTER WHAT LOOKS TO BE A DRY PERIOD ON TUESDAY...WARM FRONTAL
PROCESSES WILL BEGIN...AS LOW PRESSURE DEVELOPS OVER THE
MISSISSIPPI VALLEY. THIS WILL INCREASE THE SOUTHERLY FLOW AND
BEGIN A PATTERN OF WARM ADVECTION THAT WILL CONTINUE INTO THE LONG
TERM OF THE FORECAST. INCREASING CONVERGENCE AND MOISTURE
TRANSPORT (ESPECIALLY ALOFT ON TUESDAY NIGHT) WILL RESULT IN
PRECIPITATION CHANCES GRADUALLY INCREASING FROM WEST TO EAST
ACROSS THE CWA...THOUGH MOTION OF SHOWERS WILL BE IN MORE OF A
SSW-TO-NNE DIRECTION. THIS IS ONE PART OF THE FORECAST THAT DOES
COME WITH A BIT OF INCREASING CONFIDENCE. BECAUSE OF
THIS...TEMPERATURE ADJUSTMENTS WERE ALSO REQUIRED FOR BOTH TUESDAY
(SLIGHTLY UPWARD) AND TUESDAY NIGHT (SIGNIFICANTLY UPWARD).
PLENTIFUL CLOUDS AND MOISTURE...COMBINED REASONABLY STRONG FLOW
FOR AN OVERNIGHT PERIOD...SUPPORTS THIS DECISION. THE CURRENT
GRIDS WERE INCREASED BY 5-7 DEGREES...BUT IF SOME OF THE RAW
MODELS ARE TO BE BELIEVED...THIS MAY NOT EVEN BE ENOUGH.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
UPPER LEVEL PATTERN WILL TRANSITION TO A HIGHLY AMPLIFIED REGIME
THROUGH THE EXTENDED PERIOD. THERE CONTINUES TO BE ISSUES WITH
TIMING AND RUN TO RUN CONTINUITY WITH MAJOR SYNOPTIC SYSTEMS TO
AFFECT OUR REGION. LOOKING AT THE VARIOUS OPERATIONAL MODELS...HAVE
DECIDED TO GO WITH A 25 PERCENT 12Z ECMWF AND A 75 PERCENT 12Z GFS.
WE ARE GETTING TO THE POINT IN THE FORECAST WHERE DIURNAL RISE AND
FALL WILL NOT CUT IT WITH FRONTS MOVING THROUGH AND WAVES OF LOW
PRESSURE RIDING ALONG THE FRONTAL BOUNDARY.
ON WEDNESDAY...LONG WAVE TROUGH WILL BE CARVING ITSELF OUT OVER THE
WESTERN U.S. FIRST WEATHER ISSUE IS THE AMOUNT OF ENERGY THAT WILL
EJECT FROM THIS FEATURE ACROSS THE NORTHERN PLAINS AND INTO CENTRAL
CANADA. GFS IS STRONGER AND FASTER WITH THIS ENERGY WHILE THE ECMWF
IS SLOWER...AND THIS HAS BEEN THE CASE OVER THE LAST SVRL RUNS. THIS
WILL HAVE FRONTAL IMPLICATIONS THROUGH OUR REGION WEDNESDAY INTO
THURSDAY. WITH AFOREMENTIONED BLEND...IT ALLOWS FOR A COLD FRONT TO
MOVE THROUGH THE REGION WEDNESDAY NIGHT...BUT NOT AS FAST AS THE GFS
INDICATES. IN ADVANCE OF THE FRONT...WAA SHOWERS ARE FORECAST TO
BREAK OUT AND LIKELY POPS SEEM REASONABLE AT THIS TIME.
FOR THE PERIOD THURSDAY INTO FRIDAY...THIS TIME FRAME IS SHAPING UP
TO BE INCLEMENT AS COLD FRONT SAGS TO OUR SOUTHEAST AND BECOMES
QUASI STATIONARY AS WAVES OF LOW PRESSURE RIDE ALONG IT. THESE WAVES
WILL BRING A SHOT OF FRONTOGENETIC FORCING TO OUR REGION LATE
THURSDAY INTO THURSDAY NIGHT WITH ANOTHER ROUND OF MID TO UPR LVL
FORCING FRIDAY INTO FRIDAY NIGHT. DURING THIS TIME...COLD AIR WILL
SLOWLY SEEP INTO THE REGION FROM THE NORTHWEST. AS SUCH...THERE WILL
BE SOME WINTRY PCPN TYPE ISSUES AS LOW LEVELS COOL BUT AIR ABOVE
WILL BE SLOWER TO COOL. STILL TO EARLY TO GET SPECIFIC GIVEN THE
THERMAL FIELD OSCILLATIONS AT THIS POINT SO JUST HAVE RAIN/SNOW
MENTIONED. LIKELY POPS STILL SEEM REASONABLE FOR MOST OF THE REGION
WITH EACH WAVE RIPPLING BY.
BY FRIDAY NIGHT INTO SATURDAY...COLD ARCTIC HIGH PRESSURE WILL WEDGE
SOUTHEAST INTO OUR AREA. THIS SHOULD PUSH THE PCPN OUT OF THE AREA
BY SATURDAY. THE HIGH WILL SET UP ACROSS THE REGION SATURDAY NIGHT
AND WILL MOVE EAST BY SUNDAY. THIS SHOULD GIVE THE REGION A DRY BUT
COLD PERIOD OF WEATHER.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
A WEAK COLD FRONT/WIND SHIFT WILL DISSIPATE OVER THE OHIO VALLEY
OVERNIGHT TONIGHT AS IT PROGRESSES SOUTHEAST. CLOUD COVER
ASSOCIATED WITH THIS FRONT WILL PRIMARILY BE AN AS DECK. BEFORE
THIS OCCURS...SC OVER AND SOUTHEAST OF I-71 CORRIDOR WILL SLOWLY
ERODE FROM W-E THIS AFTERNOON. ABUNDANT MOISTURE SHOULD ALLOW SC
TO RE-DEVELOP THIS EVENING AND OVERNIGHT ONCE THE LOWER LEVELS
STRATIFY. SOME MVFR VSBYS ARE EXPECTED AND WILL BECOME MORE LIKELY
OVERNIGHT IF THE LOWER STRATUS IS A BIT MORE CUMULUS WITH WIDER
BREAKS. DISSIPATED FRONT OVER THE REGION WILL LEAD TO CONTINUED
LOW AND MID LEVEL MOISTURE WITH LIGHT AND SOMETIMES VARIABLE
WINDS.
OUTLOOK...MVFR CEILINGS POSSIBLE THROUGH TUESDAY MORNING. IFR
CEILINGS AND MVFR VISIBILITIES WILL BE POSSIBLE LATE MONDAY NIGHT.
MVFR CEILINGS AND VISIBILITIES POSSIBLE AGAIN WEDNESDAY INTO
THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS NORMAN OK
548 PM CST MON DEC 2 2013
.AVIATION...03 DEC 00Z TAF ISSUANCE...
MAJOR AVIATION CONCERN WILL BE DECREASED VISIBILITIES DUE TO BR
AND FG OVERNIGHT. INITIAL ANALYSIS WOULD INDICATED THAT
VISIBILITIES WILL NOT BE AS POOR AS LAST NIGHT. HOWEVER... WILL
NEED TO KEEP A CLOSE EYE ON KOKC AND KOUN THROUGH THE 06Z ISSUANCE
AS VISIBILITIES MAY BE WORSE THAN THE 3SM CURRENTLY IN THE TAFS.
BEST LOCATIONS FOR DENSE FOG WILL BE EAST OF THE I-35 CORRIDOR.
HAVE MENTIONS OF OF 5SM BR AT ALL SITES EXCEPT KGAG AND KWWR
OVERNIGHT THROUGH EARLY TUE MORNING. WINDS WILL REMAIN OUT OF THE
S/SW THROUGH THE END OF THE PERIOD.
JTK
&&
.PREV DISCUSSION... /ISSUED 521 PM CST MON DEC 2 2013/
UPDATE...
ISSUED A DENSE FOG ADVISORY FROM 7 PM TONIGHT TO 10 AM TUESDAY
ROUGHLY ALONG AND EAST OF I-35.
DISCUSSION...
DENSE FOG WILL AGAIN DEVELOP TONIGHT IN THE OKLAHOMA CITY...
DURANT...ARDMORE...PAULS VALLEY...STILLWATER...AND PONCA
CITY AREAS. LATEST HRRR RUNS HAVE BEEN CONSISTENT WITH DEVELOPING
DENSE FOG DEVELOPING AROUND 7 PM THIS EVENING AROUND COALGATE AND
ATOKA THEN EXPANDING IT NORTH AND WEST...WHICH SEEMS REASONABLE.
THE DENSE FOG SHOULD ARRIVE IN THE OKLAHOMA CITY METRO AREA
BETWEEN 10 PM AND 1 AM.
VISIBILITIES WILL BE 1/4 MILE OR LESS IN MANY LOCATIONS IN
THE ADVISORY AREA LATE TONIGHT INTO TUESDAY MORNING...BUT MAY
NOT BE QUITE AS LOW COMPARED TO LAST NIGHT/THIS MORNING DUE TO
A SLIGHT INCREASE IN SURFACE WINDS. ANY FOG SHOULD DISSIPATE
QUICKER TUESDAY MORNING COMPARED TO THIS MORNING DUE TO THE
STRONGER WINDS.
PRODUCTS HAVE BEEN UPDATED.
MBS
PREV DISCUSSION... /ISSUED 334 PM CST MON DEC 2 2013/
DISCUSSION...
DENSE FOG IS EXPECTED TO DEVELOP AGAIN TONIGHT...MAINLY NEAR AND
EAST OF INTERSTATE-35. DENSE FOG ADVISORIES WILL BE ISSUED LATER
THIS EVENING AS NEEDED. WE DO EXPECT THE FOG TO BURN OFF QUICKER
TOMORROW WITH INCREASING S/SW FLOW.
WRF RUNS NOW EXTENDING INTO BEGINNING OF UPCOMING STORM AND
INITIALLY ARE FORECASTING IMPACTS CLOSER TO GFS...A WETTER AND
HIGHER IMPACT SCENARIO. THE ECM STILL STICKING TO ITS FORECAST OF
LESS ACCUMULATIONS. HISTORICALLY...FOR THE EXCESSIVE ICE EVENTS WE
TYPICALLY SEE DEEP ZONE OF STRONG WARM ADVECTION/LLJ ALONG
ELEVATED BAROCLINIC ZONE/TOP OF THE FRONT/AND THIS IS NOT READILY
APPARENT HERE. STRONG/VERY STRONG MID AND UPPER LEVEL JET DYNAMICS
FORCING RESPONSE WELL ABOVE FRONTAL SURFACE IN THE FORM OF
700-600MB WAA AND FRONTOGENESIS. COINCIDENCE OF THIS FORCING AND
AVAILABLE MOISTURE/DRY-AIR ENTRAINMENT STILL LEAD US TO QUESTION
THE WIDESPREAD HIGH QPFS FROM A FEW OF THE MODELS. NONETHELESS...
GIVEN TRANSIENT TIME OF UPPER JET AND AGREEMENT OF PRECIPITATION
BAND LOCATION FROM ALL MODELS...THERE WILL LIKELY BE A NARROW BAND
OF ENHANCED PRECIP NEAR OR JUST SOUTH OF THE I-44 CORRIDOR. THE
CLOSER TO I-44 THE GREATER CHANCE FOR HEAVY SNOW. FARTHER
SOUTH...FREEZING RAIN AND ICE ACCUMULATION.
STILL LOOKS LIKE EVENT WILL BE ASSOCIATED WITH INITIAL SHIELD OF
RAIN/FREEZING RAIN WESTERN NORTH TEXAS AND SOUTHERN HALF OF
OKLAHOMA LATE WEDNESDAY NIGHT THROUGH THURSDAY. SECOND IMPULSE
INDUCES POSSIBLY HEAVIER PRECIP OVER LARGER AREA LATE THURSDAY
NIGHT THROUGH MIDDAY FRIDAY. APPEARS THAT LEAST AMOUNT OF IMPACTS
WILL BE OVER FAR NORTHERN OKLAHOMA. MODEL TRENDS WILL BE WATCHED
CLOSELY AND IF TRENDS CONTINUE WINTER STORM WATCH WILL LIKELY BE
ISSUED IN THE NEXT COUPLE OF FORECAST PACKAGES.
LIGHT SNOW AND/OR FLURRIES ALONG WITH VERY COLD CONDITIONS WILL
CONTINUE THROUGH THE WEEKEND BUT LITTLE IN THE WAY OF
ACCUMULATIONS EXPECTED SATURDAY AND SUNDAY.
03
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 41 68 35 43 / 0 0 0 0
HOBART OK 38 69 33 45 / 0 0 0 0
WICHITA FALLS TX 40 76 38 52 / 0 0 0 0
GAGE OK 33 68 26 35 / 0 0 0 0
PONCA CITY OK 39 65 31 40 / 0 0 0 0
DURANT OK 45 70 46 54 / 0 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...DENSE FOG ADVISORY UNTIL 10 AM CST TUESDAY FOR OKZ008-013-
018>020-024>032-039>043-045>048-050>052.
FIRE WEATHER WATCH TUESDAY AFTERNOON FOR OKZ014-016-021-022-
033>038-044.
TX...FIRE WEATHER WATCH TUESDAY AFTERNOON FOR TXZ083>089.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
521 PM CST MON DEC 2 2013
.UPDATE...
ISSUED A DENSE FOG ADVISORY FROM 7 PM TONIGHT TO 10 AM TUESDAY
ROUGHLY ALONG AND EAST OF I-35.
&&
.DISCUSSION...
DENSE FOG WILL AGAIN DEVELOP TONIGHT IN THE OKLAHOMA CITY...
DURANT...ARDMORE...PAULS VALLEY...STILLWATER...AND PONCA
CITY AREAS. LATEST HRRR RUNS HAVE BEEN CONSISTENT WITH DEVELOPING
DENSE FOG DEVELOPING AROUND 7 PM THIS EVENING AROUND COALGATE AND
ATOKA THEN EXPANDING IT NORTH AND WEST...WHICH SEEMS REASONABLE.
THE DENSE FOG SHOULD ARRIVE IN THE OKLAHOMA CITY METRO AREA
BETWEEN 10 PM AND 1 AM.
VISIBILITIES WILL BE 1/4 MILE OR LESS IN MANY LOCATIONS IN
THE ADVISORY AREA LATE TONIGHT INTO TUESDAY MORNING...BUT MAY
NOT BE QUITE AS LOW COMPARED TO LAST NIGHT/THIS MORNING DUE TO
A SLIGHT INCREASE IN SURFACE WINDS. ANY FOG SHOULD DISSIPATE
QUICKER TUESDAY MORNING COMPARED TO THIS MORNING DUE TO THE
STRONGER WINDS.
PRODUCTS HAVE BEEN UPDATED.
MBS
&&
.PREV DISCUSSION... /ISSUED 334 PM CST MON DEC 2 2013/
DISCUSSION...
DENSE FOG IS EXPECTED TO DEVELOP AGAIN TONIGHT...MAINLY NEAR AND
EAST OF INTERSTATE-35. DENSE FOG ADVISORIES WILL BE ISSUED LATER
THIS EVENING AS NEEDED. WE DO EXPECT THE FOG TO BURN OFF QUICKER
TOMORROW WITH INCREASING S/SW FLOW.
WRF RUNS NOW EXTENDING INTO BEGINNING OF UPCOMING STORM AND
INITIALLY ARE FORECASTING IMPACTS CLOSER TO GFS...A WETTER AND
HIGHER IMPACT SCENARIO. THE ECM STILL STICKING TO ITS FORECAST OF
LESS ACCUMULATIONS. HISTORICALLY...FOR THE EXCESSIVE ICE EVENTS WE
TYPICALLY SEE DEEP ZONE OF STRONG WARM ADVECTION/LLJ ALONG
ELEVATED BAROCLINIC ZONE/TOP OF THE FRONT/AND THIS IS NOT READILY
APPARENT HERE. STRONG/VERY STRONG MID AND UPPER LEVEL JET DYNAMICS
FORCING RESPONSE WELL ABOVE FRONTAL SURFACE IN THE FORM OF
700-600MB WAA AND FRONTOGENESIS. COINCIDENCE OF THIS FORCING AND
AVAILABLE MOISTURE/DRY-AIR ENTRAINMENT STILL LEAD US TO QUESTION
THE WIDESPREAD HIGH QPFS FROM A FEW OF THE MODELS. NONETHELESS...
GIVEN TRANSIENT TIME OF UPPER JET AND AGREEMENT OF PRECIPITATION
BAND LOCATION FROM ALL MODELS...THERE WILL LIKELY BE A NARROW BAND
OF ENHANCED PRECIP NEAR OR JUST SOUTH OF THE I-44 CORRIDOR. THE
CLOSER TO I-44 THE GREATER CHANCE FOR HEAVY SNOW. FARTHER
SOUTH...FREEZING RAIN AND ICE ACCUMULATION.
STILL LOOKS LIKE EVENT WILL BE ASSOCIATED WITH INITIAL SHIELD OF
RAIN/FREEZING RAIN WESTERN NORTH TEXAS AND SOUTHERN HALF OF
OKLAHOMA LATE WEDNESDAY NIGHT THROUGH THURSDAY. SECOND IMPULSE
INDUCES POSSIBLY HEAVIER PRECIP OVER LARGER AREA LATE THURSDAY
NIGHT THROUGH MIDDAY FRIDAY. APPEARS THAT LEAST AMOUNT OF IMPACTS
WILL BE OVER FAR NORTHERN OKLAHOMA. MODEL TRENDS WILL BE WATCHED
CLOSELY AND IF TRENDS CONTINUE WINTER STORM WATCH WILL LIKELY BE
ISSUED IN THE NEXT COUPLE OF FORECAST PACKAGES.
LIGHT SNOW AND/OR FLURRIES ALONG WITH VERY COLD CONDITIONS WILL
CONTINUE THROUGH THE WEEKEND BUT LITTLE IN THE WAY OF
ACCUMULATIONS EXPECTED SATURDAY AND SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 41 68 35 43 / 0 0 0 0
HOBART OK 38 69 33 45 / 0 0 0 0
WICHITA FALLS TX 40 76 38 52 / 0 0 0 0
GAGE OK 33 68 26 35 / 0 0 0 0
PONCA CITY OK 39 65 31 40 / 0 0 0 0
DURANT OK 45 70 46 54 / 0 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...DENSE FOG ADVISORY UNTIL 10 AM CST TUESDAY FOR OKZ008-013-
018>020-024>032-039>043-045>048-050>052.
FIRE WEATHER WATCH TUESDAY AFTERNOON FOR OKZ014-016-021-022-
033>038-044.
TX...FIRE WEATHER WATCH TUESDAY AFTERNOON FOR TXZ083>089.
&&
$$
17/04
AREA FORECAST DISCUSSION
NWS PORTLAND OR
245 PM PST SUN DEC 1 2013
.SYNOPSIS... A STRONG COLD FRONT TONIGHT TO BRINGS A PERIOD OF RAIN
TO THE PACIFIC NW...WITH RAIN TURNING TO SNOW IN THE CASCADES THROUGH
THE NIGHT AN UPPER LEVEL TROUGH SINKING S OVER THE REGION WILL KEEP A
THREAT FOR SHOWERS GOING THROUGH MON WITH SNOW LEVELS IN THE
FOOTHILLS BY AFTERNOON. A CONTINENTAL COLD FRONT WILL FOLLOW
TUE...BRINGING EVEN COLDER BUT DRIER THAT WILL REMAIN THROUGH THE
REST OF THE WEEK.
&&
.SHORT TERM...SUNDAY THROUGH TUESDAY NIGHT...FOR THE REST OF TODAY
EXPECT WINDS TO INCREASE IN MOST LOCATIONS. WE HAD A FEW GUSTS IN OUR
COAST RANGE RAWS REACH 60 MPH...AND WHILE CERTAINLY NOT
REPRESENTATIVE OF MOST COAST RANGE LOCATIONS...IT IS WINDY. AHEAD OF
THE COLD FRONT THIS EVENING THESE ELEVATIONS 1500-2000 FEET WILL
EASILY DO THIS AGAIN AS HAS STARTED TO OCCUR. LATEST GUIDANCE STILL
KEEPS WINDS UNDER HIGH WIND LEVELS ALONG THE COAST...BUT SOME EXPOSED
SPOTS MAY STILL SEE 50 MPH. LATEST HRRR ALSO KEEPS VALLEY GUSTS
LIMITED TO ABOUT 40 MPH BUT HIGHER EXPOSED HILLS WILL LIKELY DO A
LITTLE BETTER AS THERE IS A VERY STRONG 925 MB WIND FIELD. PEAK WINDS
LOOK TO BE LATE THIS AFTERNOON AND EARLY EVENING.
TRYING TO HONE IN EXACTLY HOW MUCH SNOW WILL FALL AT THE PASSES IS
PROVING TO BE A CHALLENGE. WHILE OUR SNOW ADVISORY CRITERIA IS 6" IN
12 HR...THIS MAY NOT QUITE HAPPEN AT THE PASSES BUT HIGHER ELEVATIONS
SHOULD EASILY BE ABLE TO DO THIS. MODELS APPEAR FAIRLY CONSISTENT IN
SHOWING THE CHANGEOVER TO SNOW AT PASS LEVEL NOT COMING UNTIL LATE
TONIGHT INTO MON MORNING...AFTER THE DEEPER MOISTURE AND HEAVIER
PRECIPITATION HAVE MOVED S...BUT AGREE WITH EARLIER SHIFTS REASONING
THAT SHOWERS CONTINUE ALL DAY MONDAY AS THE SHARP UPPER TROUGH SWINGS
THROUGH IN MOIST OROGRAPHIC FLOW. A SNOW ADVISORY HAS THEREFORE BEEN
ISSUED THE NORTH OREGON AND LANE COUNTY CASCADES TO TAKE INTO ACCOUNT
ADDITIONAL ACCUMULATIONS WITH THE INITIAL ONSET OF MODERATE TO HEAVY
SNOW WHEN THE CHANGEOVER OCCURS. PLUS THERE WILL BE QUITE A BIT OF
BLOWING AND DRIFTING OF SNOW IN EXPOSED LOCATIONS. THE HIGHEST IMPACT
PERIOD WILL BE LATE TONIGHT AND TOMORROW MORNING WHEN THE TRANSITION
OCCURS...BUT WILL RUN THE ADVISORY THROUGH LATE AFTERNOON/EARLY
EVENING TO ACCOUNT FOR CONTINUED SNOW SHOWERS. DID NOT DO AN
ELEVATION BASED HAZARD AS THEY WILL BE FALLING THROUGH THE PERIOD
AND DID NOT WANT TO SEND A MIXED MESSAGE...BUT MORE SIGNIFICANT SNOW
WILL BE AT 4000 FEET AND ABOVE. SNOW LEVELS WILL GET INTO THE COAST
RANGE AND FOOTHILL ELEVATIONS THOUGH GENERALLY LIGHT ACCUMULATIONS
IN SHOWERS WILL BE EXPECTED. SPOTS ABOVE 1500-2000 FEET MAY SNEAK
OUT 3 INCHES IN HEAVIER SHOWERS.
FOR THOSE HOPING FOR MORE THAN A FEW FLAKES AT THE LOWEST ELEVATIONS
MONDAY NIGHT...IT DOES NOT LOOK TOO PROMISING AS WE REMAIN IN
SOUTHERLY FLOW IN THE VALLEY BEFORE THE AIR MASS DRIES AND COOLS
ENOUGH. THE AIR MASS IS COLD ENOUGH OVERNIGHT FOR AT LEAST A MIX OF
RAIN AND SNOW SHOWERS BEFORE THINGS WIND DOWN. THE INTERESTING
DEVELOPMENT IS FOR TUESDAY NIGHT AS THE SECOND ROUND OF COLD AIR
FILTERS IN AND A STRONGER BAROCLINIC ZONE SETS UP BETWEEN THE MILD
OCEAN AND THE COLD CONTINENTAL AIR. BOTH THE NAM/SREF DEPICT SOME
WEAK LIFT MOVING THROUGH. NORTHERLY UPSLOPE FLOW THROUGH THE VALLEY
MAY BE ABLE TO WRING OUT SOME LIGHT SNOW TOWARD EUGENE...BUT THE SREF
IS THE ONLY MODEL SHOWING ENOUGH MOISTURE FOR ANYTHING MORE THAN SOME
FLURRIES...AND EVEN ITS QPF FIELD WILL ONLY RESULT IN A LIGHT DUSTING
IN ANY SHOWERS. MODELS PAINT SLIGHTLY BETTER MOISTURE IN THE CASCADES
WITH THIS WAVE SO NOTHING TO WRITE HOME ABOUT FOR NOW. TUESDAYS HIGHS
STRUGGLE TO MAKE 40 AND LOOK TO BE THE WARMEST HIGHS OF THE WEEK.
/KMD
.LONG TERM...WEDNESDAY THROUGH SATURDAY...WE LOOK TO GET A SECOND
SURGE OF COLDER AIR BEGINNING WEDNESDAY. THE COLDEST GFS ENSEMBLES
AND ECMWF MOS GUIDANCE GIVES VALLEY HIGHS IN THE LOW TO MID
30S...WITH LOWS IN THE MID TO UPPER TEENS TO AROUND 20 FOR WEDNESDAY
WITH BOTH MODELS AGREEING ON THE COLDEST DAY BEING THURSDAY.
UNCERTAINTY IN THE FORECAST FROM A PRECIPITATION PERSPECTIVE GETS
MUCH HIGHER FOR FRIDAY AND BEYOND AS THE GFS BRINGS ANOTHER SURGE OF
COLD AIR BEFORE A MODERATION IN THE AIR MASS SLOWLY OCCURS THROUGH
THE WEEKEND. MEANWHILE THE ECMWF WHICH HAD AN OVERRUNNING LIGHT SNOW
ACROSS THE REGION ON FRIDAY FROM ITS 12Z RUN YESTERDAY...THEN THE
SAME SCENARIO WAS PUSHED BACK TO FRIDAY NIGHT INTO EARLY SATURDAY ON
THE 00Z RUN TODAY...AND NOW THE 12Z RUN SHOWS SOMETHING SIMILIAR TO
THESE RUNS BEFORE BRING ANOTHER SHOT OF COLD AIR LATER IN THE
WEEKEND. THE MODELS DO AGREE ON A HIGHLY AMPLIFIED FLOW PATTERN WITH
A LARGE BLOCKING RIDGE OFFSHORE WITH NORTHERLY FLOW OVER THE NW.
WHERE THE DIFFERENCES COME IN IS THAT THERE IS LOW FURTHER OFFSHORE
THAT THE EURO MODEL ATTEMPTS TO SEND MOISTURE UP OVER THE RIDGE INTO
ALASKA THAN BACK DOWN OVER OUR AREA. MEANWHILE THE GFS DOES HAVE A
LOW MOVING THROUGH BUT IT IS NOT NEARLY AS SHARP AND THE NORTHWARD
MOVING MOISTURE IS UNABLE TO SURVIVE THE RETURN TRIP SOUTH.
WILL HOLD OFF ON ANY LARGE SCALE CHANGES AND KEEP THE LOW POP MENTION
IN FOR FRIDAY...BUT THE TEMPERATURE THEME REMAINS THE SAME...AND
EXTENDED PERIOD OF VERY COLD CONDITIONS. /KMD
&&
.AVIATION...LITTLE CHANGE IN CIGS AND VSBY TODAY IN WARM SECTOR
OF APPROACHING FRONT. EXPECT MVFR CIGS INLAND TO HOLD AROUND 2000
FT MSL WITH IFR PERSISTING ALONG THE COAST. WINDY. SURFACE WINDS
SOUTHWESTERLY WITH GUSTS TO 50 KT AT THE COAST...AND GUSTS 35 TO
40 KT POSSIBLE INLAND. WINDS ALOFT AT 4000-5000 FT MSL ARE
WESTERLY AROUND 40 KT THIS MORNING...EXPECTED TO INCREASE UP TO
60 KT THIS AFTERNOON.
KPDX AND APPROACHES...MVFR IN RAIN TODAY. LITTLE CHANGE IN CIGS
THIS AFTERNOON. CIGS LOOK TO RAPIDLY DECREASE AFTER 22Z AS FRONT
MOVES IN...FOR IFR CIGS NEAR 500-800 FT POSSIBLE 22Z-04Z.
SOUTHERLY WINDS WITH GUSTS TO 35 KT. BURGESS
&&
.MARINE...FEW UPDATES. PREVIOUS DISCUSSION FOLLOWS. SOUTHERLY
WINDS 20-25 KT WILL PERSIST THIS MORNING AS A WARM FRONT MOVES
ACROSS THE NORTHERN WATERS. STRONGER WINDS WILL MOVE NORTH TO
SOUTH THROUGH THE WATERS TODAY AND MONDAY WITH A POTENT COLD
FRONT. HAVE UPGRADED THE GALE WATCH TO A WARNING FOR THIS EVENING
INTO EARLY MONDAY SINCE MODELS CONTINUE TO SHOW GUSTS NEAR 35 KT.
BREEZY NW WINDS CONTINUE INTO MONDAY NIGHT BEFORE BUILDING HIGH
PRESSURE INLAND BRINGS A RETURN OF NE WINDS TUESDAY AFTERNOON.
A LONG PERIOD SWELL REMAINS IN THE WATERS EARLY THIS MORNING.
BUOYS CURRENTLY SHOW TWO WESTERLY SWELL TRAINS ONE AT 16
SECONDS...AND ONE AT 11 SECONDS. SINCE THESE SWELLS WOULD BE
DIFFICULT TO DISTINGUISH HAVE LEFT THEM COMBINED FOR THE FORECAST.
THE LONGER PERIOD SWELL WILL BECOME DOMINANT THIS AFTERNOON.
HOWEVER THE PERIODS WILL DROP RAPIDLY WITH STEEP (SQUARE) SEAS
LIKELY TONIGHT. THE GALE WARNING TAKES THESE STEEP SEAS INTO
ACCOUNT...WITH OVERALL SEAS PEAKING AROUND 15 FEET LATE TONIGHT.
THE SEAS WILL SUBSIDE BELOW 10 FEET LATE TUESDAY EVENING.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 PM PST THIS AFTERNOON
FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT
60 NM.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 7 AM PST MONDAY FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 7 AM
PST MONDAY.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
304 PM CST SUN DEC 1 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 304 PM CST SUN DEC 1 2013
MAIN CONCERN THE NEXT 24 H IS THE SMALL POTENTIAL FOR
PRECIPITATION...PRIMARILY OVER SOUTHWEST MINNESOTA.
ALL MODELS SHOW TWO WAVES MOVING ACROSS THE DAKOTAS AND MINNESOTA
THE NEXT 24 H. THE FIRST WAVE IS ALREADY INTO CENTRAL SD PER WATER
VAPOR IMAGERY AND WILL LIKELY BE INTO SW MN AND NW IA BY 00Z. THERE
ARE FEW ECHOES ASSOCIATED WITH THIS SYSTEM AND THOSE ARE PRIMARILY
ACROSS FAR NORTHERN SOUTH DAKOTA. WITH VERY DRY AIR BELOW 10000 FT
AND BEST FORCING FOR ASCENT IN NRN SD...HAVE REMOVED ANY CHC OF
PRECIPITATION WITH THIS WAVE. CLOSE ON ITS HEELS THOUGH IS A SECOND
WAVE. THE NAM IS FASTER AND FARTHER NORTH THAN EITHER THE RAP OR GFS
WITH THIS WAVE. CURRENT TRAJECTORY FROM WATER VAPOR FAVORS THE GFS
AND RAP AND FOLLOWED FOR LATER TONIGHT. THIS PUTS SAME STRONG
PRESSURE ADVECTION ON THE 1.5 PV SFC OVER THE CWA BY MIDNIGHT AND
CONTINUING THROUGH SUNRISE. AGAIN...MOISTURE IS A BIG ISSUE AS ALL
MODELS SHOW A 5000 TO 10000 FT DRY LAYER ABOVE THE SURFACE. FOR MUCH
OF SE SD AND NW IA...THIS DRY AIR EXPECTED TO EVAPORATE ANY
PRECIPITATION THAT DOES REACH THE SURFACE. THE ONLY PLACE THE DRY
AIR MAY BE OVERCOME IS IN SW MN WHERE IT MAY INTERACT WITH THE 850
MB BOUNDARY AND ENHANCE THE LIFT AND SATURATION. WHILE THE DRY AIR
LIKELY WILL LIMIT PCPN EVEN THERE...DID KEEP A SLIGHT CHANCE OF
PRECIPITATION FROM LATE EVENING THROUGH 12Z IN SW MN. TEMPERATURES
ALOFT ARE WELL ABOVE FREEZING...EVEN THE WET BULB TEMPERATURE WILL
BE ABOVE ZERO AND SHOULD MELT ANY PRECIPITATION ALOFT. TEMPERATURES
AT THE SURFACE THIS EVENING EXPECTED TO DROP TO AROUND 30 AND THEN
STEADY OUT AS CLOUDS AND SOUTH WINDS INCREASE. WHILE THERE IS A
POSSIBILITY TEMPERATURES COULD RISE ABOVE FREEZING AS ANY
PRECIPITATION MOVES IN...BELIEVE IT IS MOST LIKELY TO STAY JUST
BELOW FREEZING MOST OF THE NIGHT. SO ANY PRECIPITATION WILL LIKELY
BE A MIX OF FREEZING RAIN AND SLEET. AMOUNTS WILL BE LIGHT...A TRACE
TO A COUPLE HUNDREDTHS...BUT ENOUGH THAT IT COULD SLICK UP ROADS
SHOULD IT FALL.
OTHERWISE...THE PRECIPITATION WILL MOVE OFF BY MONDAY MORNING. THERE
WILL BE A LOT OF CLOUDS AROUND...ESPECIALLY EAST OF THE JAMES RIVER.
IT WILL ALSO BE VERY WARM ALOFT WITH +10C AT 925 MB IN SOUTH CENTRAL
SD WHERE THERE WILL ALSO BE SOME SUN. THEREFORE...EXPECT HIGHS TO
WARM INTO THE LOWER TO MID 50S IN SOUTH CENTRAL SD...WITH UPPER 40S
POSSIBLE OVER MUCH OF SE SD AND INTO NORTHEAST NEBRASKA AND
NORTHWEST IOWA. THE COLDEST TEMPS WILL BE IN SW MN WHERE CLOUDS WILL
BE AROUND MOST OF THE DAY AND WINDS WILL REMAIN S OR SE. BUT EVEN
THERE HIGHS WILL REACH THE LOWER 40S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 304 PM CST SUN DEC 1 2013
THERE SEEMS TO BE LITTLE SUPPORT FOR PRECIPITATION MONDAY NIGHT
AHEAD OF THE APPROACHING LOW AND COLD FRONT. WITH SOME MID LEVEL
MOISTURE LIKELY TO BE PRESENT...HAVE GONE WITH JUST A SLIGHT
CHANCE OF LIGHT RAIN/FREEZING RAIN FOR LATE MONDAY NIGHT...THAT IS
AFTER MIDNIGHT/06Z. THIS IDEA CONTINUES INTO TUESDAY AS THE LOW
AND FRONT MOVES INTO THE AREA. THE GFS...EC...AND GEM/CANADIAN ARE
FAIRLY CLOSE TO EACH OTHER ON THE PATH AND MOVEMENT OF THE
LOW/FRONT AS IT ENTERS THE AREA AND ARE ACCEPTED OVER THE
NAM...WHICH SEEMS TO BE TOO FAST AND TOO FAR NORTH. EITHER
WAY...ANY STEADY OR WIDESPREAD PRECIPITATION SHOULD STAY NORTH OF
THE AREA...AND AM GOING FOR ONLY A CHANCE OF LIGHT
PRECIPITATION...WITH THE CHANCE INCREASING SLOWLY FROM THE
NORTHWEST IN THE INCOMING COLD AIR. AHEAD OF THE COLD AIR THE
SLIGHT PRECIPITATION THREAT WILL BE LIGHT RAIN/SNOW OR JUST LIGHT
RAIN...AND OF COURSE AS THE COLD AIR ARRIVES THE CHANCE WILL BE
FOR JUST LIGHT SNOW. THIS COOLING SHOULD BE COMPLETE BY EARLY
TUESDAY EVENING...AGAIN SHOWER THAN THE NAM WOULD SUGGEST.
TEMPERATURES...QUITE MILD MONDAY NIGHT...WILL RISE JUST A LITTLE
FAR NORTHWEST...TO A FEW DEGREES SOUTHEAST...BEFORE THE COLDER AIR
TURNS THEM STEADY THEN FALLING. EVEN BY THE SLOWER GFS AND
EC...THE COLD INVASION WILL BECOME WELL ESTABLISHED BY TUESDAY
EVENING. WILL CONTINUE THE CHANCES OF LIGHT SNOW THROUGH
WEDNESDAY AND OF A FEW FLURRIES INTO THURSDAY. LACK OF SUPPORT
DOOMS ACCUMULATIONS...IF ANY...TO BE QUITE LIGHT. FRIDAY AND
SATURDAY LOOK DRY AND COLD.
THE COLD AIR WILL BE QUITE BITING WITH WIND CHILLS CURRENTLY
EXPECTED TO PI TO BELOW ZERO FAR WEST BY WEDNESDAY MORNING. BY
THURSDAY MORNING THE WHOLE AREA SHOULD BE BELOW ZERO AND THE NORTH
PERHAPS GETTING CLOSE TO THE ADVISORY BOUNDARY OF 20 BELOW ZERO.
TEMPERATURES AND WIND CHILLS WILL BE PARTLY DEPENDENT ON WHETHER
OR NOT WE GET ANY SNOW COVER...EVEN A HALF INCH TO INCH WILL HAVE
AN EFFECT. WHAT WE WILL HAVE IN THE FORECAST COULD BE A LITTLE
COLDER OR LESS COLD DEPENDING ON THAT FACTOR.
AMD GOING WITH THE EXTENDED GUIDANCE INDICATING A LOW CHANCE OF
SNOW FOR DAY 7...NEXT SUNDAY. THE EC IS THE ONLY MODEL INDICATING
ANYTHING...BUT AS FAR WEST AS IT KEEPS THE UPPER TROUGH...GOING BY
IT ALONE WOULD RATE A BIGGER THREAT...SO SLIGHT CHANCE SEEMS THE
BEST ROAD FOR NOW. THERE WILL BE SOME SLIGHT MODERATION IN THE
COLD TEMPERATURES...BUT ONLY SLIGHT AS THE COLD REGIME WILL
DOMINATE FOR A WHILE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1110 AM CST SUN DEC 1 2013
WINDS WILL REMAIN LIGHT THROUGH THE PERIOD...WITH A GRADUALLY SHIFT
TO SOUTH TOMORROW MORNING ALONG AND WEST OF I29. VFR CONDITIONS
EXPECTED AND NO PCPN EXPECT AT KHON...KFSD...AND KSUX. AT THIS
POINT...IF THERE IS ANY PCPN...MAY BE A SPRINKLE OR FLURRY
OVERNIGHT IN SW MN BUT VSBYS WOULD REMAIN ABOVE 6SM AND CIGS ABOVE
3000 FT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...SCHUMACHER
LONG TERM...
AVIATION...SCHUMACHER
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1003 PM CST MON DEC 2 2013
.UPDATE...
DENSE FOG CONTINUES TO DEVELOP ACROSS THE NORTHEAST ZONES LATE
THIS EVENING. LOCATIONS THAT HAVE NOT SEEN DENSE FOG AS OF 930 PM
WILL LIKELY SEE FALLING VISIBILITIES BEFORE MIDNIGHT.
THEREFORE...WE HAVE ISSUED A DENSE FOG ADVISORY GENERALLY ALONG
AND EAST OF A GAINESVILLE...DENTON...ROCKWALL TO ATHENS LINE.
VISIBILITIES IN THE DENSE FOG ADVISORY WILL LIKELY FALL BELOW 1/2
MILE AND REMAIN LOW THROUGH THE OVERNIGHT HOURS. THE DENSE FOG
ADVISORY MAY NEED TO BE EXPENDED FARTHER WEST OVERNIGHT IF
MOISTURE CONTINUES TO CREEP WESTWARD.
THE ONLY OTHER CHANGE THAT WILL BE MADE TO THIS FORECAST PACKAGE
WILL BE TO INCREASE CLOUD COVER ACROSS THE NORTHEAST AND ADJUST
HOURLY TEMP/DEWPOINT GRIDS.
&&
.AVIATION...
/03Z TAF AMENDMENTS/
LOW CLOUDS AND FOG HAS DEVELOPED OVER AREAS NORTHEAST OF THE DFW
METROPLEX AND THESE ARE SPREADING TO THE SOUTHWEST. A TRACK ON
THE FOG AND CLOUDS BRINGS THE IFR/LIFR CONDITIONS INTO THE METROPLEX
BETWEEN 10-12Z. THE HRRR MODEL IS THE ONLY MODEL THAT CURRENTLY
HAS A HOLD OF THE LOW CLOUDS AND FOG. WITH THE TAF
AMENDMENT...DETERIORATED THE METROPLEX TO PREVAILING 2 SM
BEGINNING 10-12Z WITH A TEMPO FOR 1 SM BKN005 BETWEEN 11/12-14Z.
IT IS POSSIBLE THAT VISIBILITIES MAY BE REDUCED TO LESS THAN 1
MILE WITH LIFR CIGS AROUND 100 FEET.
CONDITIONS ARE NOW LOOKING BETTER AT KACT AND IMPROVED THEM
OVERNIGHT TO 5 SM WITH A TEMPO FOR 3 SM.
.../PREVIOUS AVIATION DISCUSSION/...
/00Z TAFS/
CONCERNS...POTENTIAL FOR FOG OVERNIGHT/TUESDAY MORNING.
THE WINDS ACROSS THE REGION ARE LIGHT AND VARIABLE. A DRYLINE IS
LOCATED ALONG AND JUST WEST OF THE INTERSTATE 35 CORRIDOR. AS A
RESULT...ALL OF THE TAF SITES ARE PREVAILING A LIGHT SOUTH TO
SOUTHWEST WIND. WIND SPEEDS WILL REMAIN LIGHT THROUGH THE
OVERNIGHT PERIOD AND THEN INCREASE FROM THE SOUTH-SOUTHWEST TO
AROUND 10 KTS DURING THE DAY ON TUESDAY.
THE LOCATION OF THE DRYLINE WILL BE CRUCIAL TO WHERE FOG WILL
DEVELOP OVERNIGHT. AREAS EAST OF I-35 WILL LIKELY SEE FOG
OVERNIGHT BUT THE MODELS DIFFER ON WHETHER THE TAF SITES WILL BE
AFFECTED BY FOG OR NOT. IT WILL ALL DEPEND ON IF THE DRYLINE MOVES
SLIGHTLY FURTHER WEST OR MAINTAINS ITS CURRENT LOCATION. MOST OF
THE FORECAST SOUNDINGS INDICATE THAT THE LAYER OF MOISTURE NEAR
THE GROUND IS VERY SHALLOW AT THE DFW TAF SITES AND THUS IF FOG
DOES DEVELOP IT WILL LIKELY REMAIN SHALLOW. WILL KEEP A TEMPO 5 SM
AT THE DFW SITES FROM 11-14Z. THE POTENTIAL FOR FOG IS HIGHER AT
KACT AND WILL KEEP A PREVAILING GROUP FOR 5 SM BR FROM 10-15Z WITH
A TEMPO 2 SM FROM 12-14Z. ANY FOG AT THE TAF SITES WILL IMPROVE BY
14-15Z. SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE PERIOD.
82/JLD
82
&&
.PREV DISCUSSION... /ISSUED 324 PM CST MON DEC 2 2013/
THERE REMAINS SOME UNCERTAINTY IN THE FORECAST FROM WEDNESDAY ON...
WHICH INCLUDES FRONTAL TIMING...TIMING OF PRECIPITATION EVENTS AND
DURATION AND AMOUNTS OF WINTRY PRECIPITATION. MOSTLY...THIS FORECAST
IS BASED ON THE GFS SOLUTIONS OF THE PAST SEVERAL RUNS...BUT DID
BIAS SOME PARAMETERS TOWARD THE ECMWF SOLUTIONS OF TODAY AND
YESTERDAY MORNING.
FOR TONIGHT THROUGH TUESDAY NIGHT. IT WILL BE NICE THIS EVENING
BUT DO THINK A SECOND ROUND OF FOG AND CLOUDS WILL OCCUR ALONG
PARTS OF THE RED RIVER AND AREAS EAST OF THE I-35 CORRIDOR
BEGINNING AFTER MIDNIGHT AND LASTING THROUGH MID MORNING TUESDAY.
ONCE THE FOG BURNS OFF...TUESDAY WILL BE VERY NICE WITH HIGHS IN
THE 70S TO LOWER 80S AND SOUTHWESTERLY WINDS. TUESDAY NIGHT WILL
BE MILD AND HUMID...AND SOME PATCHY FOG REMAINS POSSIBLE OVER THE
SOUTHEAST COUNTIES.
ON WEDNESDAY WE WILL SEE THE BEGINNING OF A BIG CHANGE FOR MUCH OF
THE CWA AS ANOTHER STRONG COLD FRONT ARRIVES IN THE NORTHWEST
COUNTIES AROUND OR SHORTLY AFTER SUNRISE. THE FRONT WILL PUSH
SOUTH OF I-20 AND SLOW DOWN AS SURFACE PRESSURE FALLS ACROSS NEW
MEXICO AND MUCH OF WEST TEXAS INHIBIT THE FORWARD PROGRESS
THROUGH WEDNESDAY NIGHT. THIS WILL RESULT IN HIGHS ONLY IN THE MID
50S ACROSS THE NORTHWEST TO LOWER 70S ACROSS THE SOUTHERN
COUNTIES. PRESSURE RISES NORTH OF THE FRONT RETURN IN EARNEST LATE
WEDNESDAY NIGHT/THURSDAY AND THE FRONT ALONG WITH A SECOND ARCTIC FRONT
PLOWS THROUGH THE REST OF THE CWA. THERE IS A CHANCE OF LIGHT
RAIN WEDNESDAY NIGHT... AND LIGHT RAIN/ISOLATED THUNDERSTORMS ON
THURSDAY...AS SHORTWAVE ENERGY TRANSVERSES THE REGION AND
INTERACTS WITH WARM AIR AND MOISTURE ABOVE THE ELEVATED FRONT.
NOW FOR THE PERIOD OF UNCERTAINTY...THURSDAY NIGHT THROUGH
SUNDAY. SOME THINGS ARE A GIVEN: 1) THERE WILL BE FREEZING
TEMPERATURES (ESPECIALLY AT NIGHTTIME) SPREADING SOUTHEAST ACROSS
THE CWA. 2) THERE WILL BE PERIODS OF FREEZING RAIN AND/OR SLEET
THURSDAY THROUGH SUNDAY. 3) FORECAST AMOUNTS OF ICE/SLEET WILL BE
ENOUGH TO CAUSE TRAVEL PROBLEMS. 4) SNOW IS NOT EXPECTED DUE TO A
LACK OF SATURATION WITHIN THE DENDRITIC GROWTH ZONE.
OUR MAIN CONCERN IS THE UNCERTAINTY OF WHETHER: (1) LIFT WILL BE
STRONGER THAN FORECAST AND PUSH ICE AMOUNTS INTO THE WARNING
CATEGORY. (2) MOISTURE ABOVE THE FRONT WILL INCREASE INTO THE
DENDRITIC FORMATION ZONE AND PRODUCES SNOW OVER THE NORTHWEST
COUNTIES. (3) FREEZING RAIN OR SLEET WILL BE MORE DOMINATE DURING
THE PERIOD.
CURRENT THINKING IS FOR FREEZING RAIN TO DOMINATE ON THURSDAY
NIGHT WITH LIGHT ICE ACCUMULATIONS OVER THE NORTHWEST 1/2 CWA. A
LULL IN THE PRECIPITATION SHOULD OCCUR FRIDAY NIGHT THROUGH
SATURDAY MORNING. A WINTRY MIX OF FREEZING RAIN AND SLEET WILL
OCCUR SATURDAY AFTERNOON THROUGH SUNDAY MORNING...AND LIGHT ICE
ACCUMULATIONS ARE POSSIBLE. WE ARE ISSUING A WINTER STORM OUTLOOK
THIS AFTERNOON FOR THESE EVENTS.
TEMPERATURES WILL REMAIN WAY BELOW NORMAL FRIDAY AND OVER THE
WEEKEND BUT SHOULD WARM INTO THE 40S AND LOWER 50S ON MONDAY. 75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 49 77 51 62 37 / 0 5 10 10 20
WACO, TX 50 78 54 70 42 / 0 5 10 10 20
PARIS, TX 46 71 50 63 38 / 5 5 10 10 20
DENTON, TX 45 74 45 58 34 / 0 5 10 10 20
MCKINNEY, TX 47 74 49 61 36 / 0 5 10 10 20
DALLAS, TX 50 77 53 63 39 / 0 5 10 10 20
TERRELL, TX 49 75 54 66 40 / 0 5 10 10 20
CORSICANA, TX 51 77 57 69 44 / 0 5 10 10 20
TEMPLE, TX 51 80 56 72 45 / 0 5 10 10 20
MINERAL WELLS, TX 41 78 43 58 34 / 0 5 10 10 30
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST TUESDAY FOR TXZ092>095-
103>107-120>123-135.
&&
$$
82/79
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
915 PM CST MON DEC 2 2013
.AVIATION...
/03Z TAF AMENDMENTS/
LOW CLOUDS AND FOG HAS DEVELOPED OVER AREAS NORTHEAST OF THE DFW
METROPLEX AND THESE ARE SPREADING TO THE SOUTHWEST. A TRACK ON
THE FOG AND CLOUDS BRINGS THE IFR/LIFR CONDITIONS INTO THE METROPLEX
BETWEEN 10-12Z. THE HRRR MODEL IS THE ONLY MODEL THAT CURRENTLY
HAS A HOLD OF THE LOW CLOUDS AND FOG. WITH THE TAF
AMENDMENT...DETERIORATED THE METROPLEX TO PREVAILING 2 SM
BEGINNING 10-12Z WITH A TEMPO FOR 1 SM BKN005 BETWEEN 11/12-14Z.
IT IS POSSIBLE THAT VISIBILITIES MAY BE REDUCED TO LESS THAN 1
MILE WITH LIFR CIGS AROUND 100 FEET.
CONDITIONS ARE NOW LOOKING BETTER AT KACT AND IMPROVED THEM
OVERNIGHT TO 5 SM WITH A TEMPO FOR 3 SM.
.../PREVIOUS AVIATION DISCUSSION/...
/00Z TAFS/
CONCERNS...POTENTIAL FOR FOG OVERNIGHT/TUESDAY MORNING.
THE WINDS ACROSS THE REGION ARE LIGHT AND VARIABLE. A DRYLINE IS
LOCATED ALONG AND JUST WEST OF THE INTERSTATE 35 CORRIDOR. AS A
RESULT...ALL OF THE TAF SITES ARE PREVAILING A LIGHT SOUTH TO
SOUTHWEST WIND. WIND SPEEDS WILL REMAIN LIGHT THROUGH THE
OVERNIGHT PERIOD AND THEN INCREASE FROM THE SOUTH-SOUTHWEST TO
AROUND 10 KTS DURING THE DAY ON TUESDAY.
THE LOCATION OF THE DRYLINE WILL BE CRUCIAL TO WHERE FOG WILL
DEVELOP OVERNIGHT. AREAS EAST OF I-35 WILL LIKELY SEE FOG
OVERNIGHT BUT THE MODELS DIFFER ON WHETHER THE TAF SITES WILL BE
AFFECTED BY FOG OR NOT. IT WILL ALL DEPEND ON IF THE DRYLINE MOVES
SLIGHTLY FURTHER WEST OR MAINTAINS ITS CURRENT LOCATION. MOST OF
THE FORECAST SOUNDINGS INDICATE THAT THE LAYER OF MOISTURE NEAR
THE GROUND IS VERY SHALLOW AT THE DFW TAF SITES AND THUS IF FOG
DOES DEVELOP IT WILL LIKELY REMAIN SHALLOW. WILL KEEP A TEMPO 5 SM
AT THE DFW SITES FROM 11-14Z. THE POTENTIAL FOR FOG IS HIGHER AT
KACT AND WILL KEEP A PREVAILING GROUP FOR 5 SM BR FROM 10-15Z WITH
A TEMPO 2 SM FROM 12-14Z. ANY FOG AT THE TAF SITES WILL IMPROVE BY
14-15Z. SKIES WILL REMAIN MOSTLY CLEAR THROUGH THE PERIOD.
82/JLD
82
&&
.PREV DISCUSSION... /ISSUED 324 PM CST MON DEC 2 2013/
THERE REMAINS SOME UNCERTAINTY IN THE FORECAST FROM WEDNESDAY ON...
WHICH INCLUDES FRONTAL TIMING...TIMING OF PRECIPITATION EVENTS AND
DURATION AND AMOUNTS OF WINTRY PRECIPITATION. MOSTLY...THIS FORECAST
IS BASED ON THE GFS SOLUTIONS OF THE PAST SEVERAL RUNS...BUT DID
BIAS SOME PARAMETERS TOWARD THE ECMWF SOLUTIONS OF TODAY AND
YESTERDAY MORNING.
FOR TONIGHT THROUGH TUESDAY NIGHT. IT WILL BE NICE THIS EVENING
BUT DO THINK A SECOND ROUND OF FOG AND CLOUDS WILL OCCUR ALONG
PARTS OF THE RED RIVER AND AREAS EAST OF THE I-35 CORRIDOR
BEGINNING AFTER MIDNIGHT AND LASTING THROUGH MID MORNING TUESDAY.
ONCE THE FOG BURNS OFF...TUESDAY WILL BE VERY NICE WITH HIGHS IN
THE 70S TO LOWER 80S AND SOUTHWESTERLY WINDS. TUESDAY NIGHT WILL
BE MILD AND HUMID...AND SOME PATCHY FOG REMAINS POSSIBLE OVER THE
SOUTHEAST COUNTIES.
ON WEDNESDAY WE WILL SEE THE BEGINNING OF A BIG CHANGE FOR MUCH OF
THE CWA AS ANOTHER STRONG COLD FRONT ARRIVES IN THE NORTHWEST
COUNTIES AROUND OR SHORTLY AFTER SUNRISE. THE FRONT WILL PUSH
SOUTH OF I-20 AND SLOW DOWN AS SURFACE PRESSURE FALLS ACROSS NEW
MEXICO AND MUCH OF WEST TEXAS INHIBIT THE FORWARD PROGRESS
THROUGH WEDNESDAY NIGHT. THIS WILL RESULT IN HIGHS ONLY IN THE MID
50S ACROSS THE NORTHWEST TO LOWER 70S ACROSS THE SOUTHERN
COUNTIES. PRESSURE RISES NORTH OF THE FRONT RETURN IN EARNEST LATE
WEDNESDAY NIGHT/THURSDAY AND THE FRONT ALONG WITH A SECOND ARCTIC FRONT
PLOWS THROUGH THE REST OF THE CWA. THERE IS A CHANCE OF LIGHT
RAIN WEDNESDAY NIGHT... AND LIGHT RAIN/ISOLATED THUNDERSTORMS ON
THURSDAY...AS SHORTWAVE ENERGY TRANSVERSES THE REGION AND
INTERACTS WITH WARM AIR AND MOISTURE ABOVE THE ELEVATED FRONT.
NOW FOR THE PERIOD OF UNCERTAINTY...THURSDAY NIGHT THROUGH
SUNDAY. SOME THINGS ARE A GIVEN: 1) THERE WILL BE FREEZING
TEMPERATURES (ESPECIALLY AT NIGHTTIME) SPREADING SOUTHEAST ACROSS
THE CWA. 2) THERE WILL BE PERIODS OF FREEZING RAIN AND/OR SLEET
THURSDAY THROUGH SUNDAY. 3) FORECAST AMOUNTS OF ICE/SLEET WILL BE
ENOUGH TO CAUSE TRAVEL PROBLEMS. 4) SNOW IS NOT EXPECTED DUE TO A
LACK OF SATURATION WITHIN THE DENDRITIC GROWTH ZONE.
OUR MAIN CONCERN IS THE UNCERTAINTY OF WHETHER: (1) LIFT WILL BE
STRONGER THAN FORECAST AND PUSH ICE AMOUNTS INTO THE WARNING
CATEGORY. (2) MOISTURE ABOVE THE FRONT WILL INCREASE INTO THE
DENDRITIC FORMATION ZONE AND PRODUCES SNOW OVER THE NORTHWEST
COUNTIES. (3) FREEZING RAIN OR SLEET WILL BE MORE DOMINATE DURING
THE PERIOD.
CURRENT THINKING IS FOR FREEZING RAIN TO DOMINATE ON THURSDAY
NIGHT WITH LIGHT ICE ACCUMULATIONS OVER THE NORTHWEST 1/2 CWA. A
LULL IN THE PRECIPITATION SHOULD OCCUR FRIDAY NIGHT THROUGH
SATURDAY MORNING. A WINTRY MIX OF FREEZING RAIN AND SLEET WILL
OCCUR SATURDAY AFTERNOON THROUGH SUNDAY MORNING...AND LIGHT ICE
ACCUMULATIONS ARE POSSIBLE. WE ARE ISSUING A WINTER STORM OUTLOOK
THIS AFTERNOON FOR THESE EVENTS.
TEMPERATURES WILL REMAIN WAY BELOW NORMAL FRIDAY AND OVER THE
WEEKEND BUT SHOULD WARM INTO THE 40S AND LOWER 50S ON MONDAY. 75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 49 77 51 62 37 / 0 5 10 10 20
WACO, TX 50 78 54 70 42 / 0 5 10 10 20
PARIS, TX 48 71 50 63 38 / 5 5 10 10 20
DENTON, TX 45 74 45 58 34 / 0 5 10 10 20
MCKINNEY, TX 47 74 49 61 36 / 0 5 10 10 20
DALLAS, TX 50 77 53 63 39 / 0 5 10 10 20
TERRELL, TX 49 75 54 66 40 / 0 5 10 10 20
CORSICANA, TX 51 77 57 69 44 / 0 5 10 10 20
TEMPLE, TX 51 80 56 72 45 / 0 5 10 10 20
MINERAL WELLS, TX 41 78 43 58 34 / 0 5 10 10 30
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
82/79
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
916 PM CST MON DEC 2 2013
.UPDATE...
BAND OF PRECIPITATION HAS REMAINED MAINLY SNOW...WITH SOME GRAUPEL
AND RAIN ON THE LEADING EDGE. PRECIPITATION HAS ALLOWED WET BULB
TEMPS TO FALL TO 0C ALL THE WAY TO THE SURFACE ON RAP SOUNDINGS
WHICH IS KEEPING THE PCPN ALL SNOW. EMBEDDED MODERATE SNOW BANDS
HAVE OVERWHELMED THE GENERALLY ABOVE FREEZING SURFACES AND IS
ACCUMULATING ON GRASSY AREAS AND PRODUCING A THIN LAYER OF SNOW
ON ROADS WITH SLICK SPOTS REPORTED FROM MADISON WEST ON SOCIAL
MEDIA AND DOT WEB PAGE.
THE WARMER SOUTHEAST FLOW OFF OF LAKE MICHIGAN SHOULD HELP
ROADS STAY WET AT LOCATIONS ALONG AND NEAR THE LAKESHORE AS THE
BAND MOVES ACROSS SOUTHEAST WISCONSIN...BUT COOLER INLAND
LOCATIONS MAY SEE A LIGHT COATING ON ROADS. WILL KEEP THE SPS
GOING AND FOLLOW THE BAND THROUGH THE REGION.
LATEST HRRR HAS SHOWN A TROUBLING TREND OF SOME MINOR RE-
DEVELOPMENT ON THE BACK SIDE OF THIS INITIAL BAND THAT DOES NOT
CLEAR THE FAR NORTHEAST UNTIL AFTER 5 AM TUESDAY MORNING...WHICH
THE LATEST NAM IS ALSO INDICATING.
&&
.AVIATION/06Z TAFS/...
WATCHING UPSTREAM OBS TO SEE IF THERE MAY BE A CHANCE FOR
MVFR/VFR CIGS AND VSBYS AFTER THIS INITIAL BAND OF SNOW MOVES
THROUGH KMSN AROUND 04Z...AND EASTERN TAF SITES BETWEEN 06Z AND
07Z. LATEST NAM SUPPORTS RETURN OF IFR/LIFR CONDITIONS OVERNIGHT
AS SURFACE WARM FRONT APPROACHES...THEN STALLS ALONG THE WI/IL
BORDER...KEEPING A COOL MOIST EASTERLY SURFACE FLOW OFF THE LAKE
THAT IS TRAPPED UNDER INVERSION WITH INCREASINGLY WARMER AIR
STREAMING IN ON SOUTHERLY WINDS ALOFT. AFTER A BREAK IN THE
PRECIPITATION...SHOULD SEE RAIN RETURN TO ALL TAF SITES BY MID TO
LATE MORNING WITH NEXT SHORT WAVE MOVING THROUGH THE REGION. WILL
ONLY SEE A SLIGHT IMPROVEMENT TO CIGS AND VSBYS WITH THE
RAIN...BUT STILL EXPECT IFR THROUGH 06Z WED.
&&
.MARINE...
SOUTHEAST WINDS ARE INCREASING AT SHEBOYGAN C-MAN AND PORT
WASHINGTON. SHOULD SEE FAIRLY FREQUENT GUSTS TO BETWEEN 20 AND 25
KNOTS AFTER MIDNIGHT WITH BUILDING WAVES THROUGH THE OVERNIGHT.
LATEST NAM AND GFS STILL INDICATING WINDS EASING OVER SOUTHERN
ZONES AS WARM FRONT APPROACHES. NO CHANGE TO GOING SMALL CRAFT
ADVISORY AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 332 PM CST MON DEC 2 2013/
TONIGHT AND TUESDAY...FORECAST CONFIDENCE MEDIUM.
THE FIRST WAVE OF PRECIPITATION IS APPARENT ON RADAR AS A NARROW
BAND WITH DECENT REFLECTIVITY OVER FAR EASTERN MN AND EASTERN IOWA
AT 3 PM THIS AFTERNOON. THIS IS ASSOCIATED WITH A WEAK BAND OF 850-
600MB FRONTOGENESIS AND PERSISTENT 925-850MB WARM AIR ADVECTION AND
MODEST 700MB OMEGA. MOST OBSERVATIONS BENEATH THE BAND SHOW SNOW IN
MN AND RAIN IN IOWA. THIS HAS A STEADY TRACK EASTWARD AND SHOULD
ARRIVE IN MADISON AROUND 1Z OR 7 PM AS PROBABLY WET SNOW. SINCE IT
WILL ONLY LAST UP TO TWO HOURS AND FALLING INTO SURFACE TEMPS ABOVE
FREEZING...NO ACCUMULATION IS EXPECTED. 19Z HRRR MODEL SEEMS TO HAVE
A HANDLE ON THE PRECIP FOR THE EVENING. TIMING FOR MILWAUKEE RAIN
LOOKS LIKE 4Z TO 8Z.
PRECIP TYPE IS MORE UNCERTAIN ACROSS THE NORTHERN MKX FORECAST AREA.
EXPECTING MAINLY SNOW HERE WITH UP TO A HALF INCH OF ACCUMULATION.
SURFACE TEMPERATURES WILL BE A BIT COOLER HERE...SO THERE IS A SMALL
POSSIBILITY FOR FREEZING DRIZZLE IF THERE ARE POCKETS OF AIR BELOW
FREEZING.
EXPECTING A BREAK IN RAIN AFTER THIS FIRST BAND MOVES THROUGH. THERE
COULD BE DRIZZLE AS MID LEVELS DRY OUT A LITTLE PER MODEL SOUNDINGS.
THEN ANOTHER ROUND OF RAIN IS EXPECTED ACROSS SOUTHERN WI TUESDAY
MORNING WHICH COULD PERSIST THROUGH THE AFTERNOON. THERE IS ANOTHER
WAVE OF FRONTOGENESIS...850MB WARM AIR ADVECTION AND 700MB OMEGA
WITH A 500MB VORT MAX. EXPECTING STRATIFORM RAIN OFF AND ON THROUGH
MUCH OF THE DAY TUESDAY WITH LOW CLOUDS AND LIGHT FOG...AS WELL AS
A 10MPH SOUTHEAST BREEZE WITH HIGHER GUSTS.
TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE IS LOW TO
MEDIUM.
CONFIDENCE IS CERTAINLY CHALLENGED THIS PERIOD AS THE MAJOR MODEL
SIMULATIONS CONTINUE TO HAVE TWO VERY DIFFERENT SOLUTIONS. WE
HAVE THE MORE AMPLIFIED AND FASTER SOLUTION OF THE GFS/NAM...AND
THE SLOWER...DELAYED AMPLIFICATION OF THE ECMWF/GEM. TO BE THIS
CLOSE TO THE EVENT AND CONTINUE TO SEE SUCH PERSISTENT DISPARITY
IN MODEL RUNS IS PRETTY UNUSUAL. DISCUSSION FROM THE MODEL
DIAGNOSTIC FOLKS SUGGEST THE GFS/NAM ARE TOO AMPLIFIED GIVEN
DOWNSTREAM CHARACTERISTICS. THE APPROACH HAS BEEN TO TAKE A
CONSENSUS/BLEND WITH A STRONGER NOD TOWARD THE SLOWER SOLUTIONS.
FOR US...OUR ISSUES ARE MINOR COMPARED TO OUR NEIGHBORS TO THE
NORTH THAT HAVE TO DEAL WITH THE POTENTIAL OF BIG SNOWFALL
AMOUNTS. WE WILL BE WARM ENOUGH TO KEEP ANY PRECIPITATION IN THE
FORM OF RAIN. WE COULD SEE SOME SNOW MIX IN RIGHT ALONG AND BEHIND
THE COLD FRONT MOVING THROUGH ON WEDNESDAY. JUST WHEN THAT FRONT
MOVES THROUGH WILL HAVE TO GET WORKED OUT OVER THE NEXT COUPLE OF
DAYS. BUT CURRENT THINKING HAS IT COMING THROUGH MADISON AROUND
MID DAY WEDNESDAY AND MILWAUKEE ABOUT MID AFTERNOON.
WEDNESDAY NIGHT AND BEYOND...FORECAST CONFIDENCE IS MEDIUM.
WE COULD SEE SOME FLURRIES OR VERY LIGHT SNOW WEDNESDAY NIGHT
UNDER A STRONG COLD AIR ADVECTION PATTERN IN THE WAKE OF THE COLD
FRONT. TEMPERATURES WILL FALL PRETTY HARD...BUT HAVE BACKED OFF A
BIT FOR WEDNESDAY NIGHT AND THURSDAY GIVEN THE POTENTIAL FOR A
SLOWER INFLUX OF COLD AIR DEPICTED BY THE ECMWF/GEM SOLUTIONS.
BUT...THE COLD AIR WILL BE WELL ESTABLISHYED BY FRIDAY...
LINGERING THROUGH THE WEEKEND. WE/RE STILL LOOKING AT HIGHS FRIDAY
AND SATURDAY IN THE TEENS...MODERATING A BIT INTO THE 20S BY
SUNDAY AND MONDAY. LOWS WILL BE IN THE SINGLE DIGITS. THE GFS AND
ECMWF ARE BRINGING A WEAKISH LOOKING LOW PRESSURE SYSTEM THROUGH
THE OHIO VALLEY ON SUNDAY THAT COULD BRING SOME LIGHT SNOW TO THE
AREA.
AVIATION/00Z TAFS/...
MID LEVEL CLOUDS WILL LOWER THROUGHOUT THE EVENING. A NORTH TO SOUTH
ORIENTED BAND OF PRECIPITATION WILL MOVE EASTWARD ACROSS SOUTHERN WI
THIS EVENING...THEN HANG UP IN A WEST TO EAST ORIENTATION ACROSS
CENTRAL WI LATE TONIGHT THROUGH TUESDAY. PRECIP SHOULD START AS WET
SNOW IN MADISON AND NORTH OF MADISON THEN TRANSITION TO RAIN OVER
TIME TONIGHT. MILWAUKEE AND SOUTH WILL BE MAINLY RAIN. WITH SURFACE
TEMPS ABOVE FREEZING FOR THE NIGHT...NOT EXPECTING ACCUMULATION
EXCEPT POSSIBLY IN FOND DU LAC AND SHEBOYGAN AREAS. AFTER THE BAND
PASSES...THERE COULD BE DRIZZLE AND LIGHT FOG AND IFR OR LOWER
CEILINGS LATE TONIGHT THROUGH TUESDAY MORNING.
ANOTHER ROUND OF LIGHT RAIN IS EXPECTED TO SPREAD NORTHEASTWARD
ACROSS SOUTHERN WI TUESDAY MORNING AND PERSIST THROUGH MUCH OF THE
DAY ALONG A WARM FRONT. IFR CIGS SHOULD IMPROVE TO FUEL ALTERNATE
THE AFTERNOON FROM MILWAUKEE AND MADISON SOUTHWARD.
MARINE...
A SMALL CRAFT ADVISORY IS IN EFFECT FOR AREAS NORTH OF THE NORTH
POINT LIGHT FROM MIDNIGHT TONIGHT THROUGH WEDNESDAY MORNING. AREAS
SOUTH OF NORTH POINT LIGHT MAY NEED TO BE ADDED. INCREASING
SOUTHEAST WINDS TONIGHT THROUGH TUE AFTERNOON WILL LEAD TO HIGH
WAVES. EXPECT WAVES TO SUBSIDE AS WINDS BECOME OFFSHORE...SOMETIME
WEDNESDAY MORNING. A STRONG COLD FRONT WILL THEN SWEEP EAST ACROSS
LAKE MI ON WED. BRISK AND GUSTY WNWLY FLOW WILL THEN PREVAIL THE
REMAINDER OF THE WEEK. A SMALL CRAFT ADVISORY MAY BE NEEDED ALL THE
WAY INTO SATURDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST WEDNESDAY
FOR LMZ643-644.
&&
$$
UPDATE...REM
TONIGHT/TUESDAY AND AVIATION/MARINE...MRC
TUESDAY NIGHT THROUGH MONDAY...DAVIS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
307 PM CST SUN DEC 1 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 307 PM CST SUN DEC 1 2013
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH DROPPING DOWN THROUGH WESTERN BRITISH
COLUMBIA...WITH NEARLY ZONAL FLOW DOWNSTREAM ACROSS THE NORTHERN
U.S.. WITHIN THIS ZONAL FLOW...THERE ARE SOME WEAK SHORTWAVES...ONE
OVER SOUTHEAST BRITISH COLUMBIA AND A SECOND IN THE DAKOTAS. DPVA
AND WARM ADVECTION AHEAD OF THIS SECOND SHORTWAVE HAS BEEN SPREADING
MID/HIGH CLOUDS DOWNSTREAM INTO THE FORECAST AREA. SO FAR THE ONLY
SPOT PRECIPITATION HAS BEEN FALLING OUT OF THESE CLOUDS HAS BEEN
ACROSS CENTRAL NORTH DAKOTA. COMPARING THE 12Z BIS AND MPX
SOUNDINGS...MUCH MORE MOISTURE EXISTED ACROSS NORTH DAKOTA...
RELATIVELY SPEAKING AS PRECIPITABLE WATER AMOUNTS ARE ONLY 0.13
INCHES DIFFERENT. FARTHER EAST...HIGH PRESSURE HAS BUILT INTO THE
FORECAST AREA AT THE SURFACE BEHIND LAST NIGHTS COLD FRONT. THE
STRATUS THAT WAS COMING IN AHEAD OF THE HIGH PRESSURE AREA HAS
STALLED MOSTLY NORTH OF HWY 29 IN WI. 925MB TEMPS ARE ABOUT 3C
COOLER TODAY AND AS RESULT...THE SUN HAS ONLY ALLOWED THE
TEMPERATURES TO CLIMB INTO THE 30S.
MODELS ARE ALL IN GOOD AGREEMENT DIVING THE POTENT UPPER TROUGH
OVER WESTERN BRITISH COLUMBIA DIGGING INTO THE PACIFIC NORTHWEST
AND NORTHERN ROCKIES. THIS IN TURN SENDS THE SHORTWAVE IN SOUTHERN
BRITISH COLUMBIA EASTWARD...CROSSING THE FORECAST AREA MONDAY
AFTERNOON. PRIOR TO THIS SHORTWAVE...WE FIRST MUST DEAL WITH THE
SHORTWAVE IN THE DAKOTAS WHICH IS PROGGED TO COME ACROSS THE AREA
THIS EVENING. IT APPEARS ALL THE SHORTWAVE WILL BRING IS CONTINUED
MID/HIGH CLOUDS AS THE LOW LEVELS REMAIN DRY AS SHOWN NICELY IN
THE 12Z MPX SOUNDING. NOW OVERNIGHT...INCREASING 280-295K
ISENTROPIC LIFT OVER THE DAKOTAS AHEAD OF THE APPROACHING BRITISH
COLUMBIA SHORTWAVE WILL LIKELY DEVELOP PRECIPITATION FROM THE
DAKOTAS INTO CENTRAL MINNESOTA. MODELS HAVE SLOWED DOWN THE
PRECIPITATION SPREAD SOUTHEAST INTO THE FORECAST AREA PRIOR TO
12Z...WHICH SEEMS REASONABLE AND HAVE DELAYED THE PRECIPITATION
CHANCES TO LATE IN THE NIGHT. THE BETTER CHANCES FOR PRECIPITATION
COME DURING THE DAY MONDAY AS THE SHORTWAVE CROSSES THE FORECAST
AREA...PROVIDING DPVA AND A SPREAD SOUTHEASTWARD OF THE 280-295K
ISENTROPIC LIFT INTO THE FORECAST AREA. STILL...THERE ARE
DIFFERENCES WITH THE MAIN PRECIP AXIS. THE 01.12Z
CANADIAN...01.00Z/01.12Z ECMWF SUGGEST AN ALIGNMENT FROM CENTRAL
MN INTO NORTHEAST IA/FAR SOUTHWEST WI...THE 01.12Z NAM PLACES IT
MOSTLY NORTH OF I-94...AND THE 01.12Z GFS IS SORT OF A SPLIT
BETWEEN THE TWO. WITH NO CLEAR SIGNAL ON WHICH MODEL GROUP MIGHT
VERIFY...HAVE FOLLOWED A COMPROMISE. THIS COMPROMISE RESULTS IN
LOW CHANCES...20-40...BECAUSE OF THE VARIABILITY OF LOCATION.
FUTURE SHIFTS SHOULD BE ABLE TO RAISE CHANCES AND HONE IN ON AN
ALIGNMENT OF THE PRECIP AXIS.
WITH 925MB AND 850MB TEMPS PROGGED AT OR BELOW 0C ACROSS MUCH OF
THE FORECAST AREA AND EVAPORATIVE COOLING LIKELY TO TAKE PLACE
WHERE IT DOES PRECIPITATE...THINKING THAT THE PRECIPITATION WILL
MAINLY FALL IN THE FORM OF SNOW. THERE MAY BE SOME MIXING WITH
RAIN POSSIBLE IN THE AFTERNOON IF TEMPERATURES WARM INTO THE MID
TO POSSIBLY UPPER 30S AS EXPECTED. NO MODEL IS THAT HEAVY ON
QPF...MOSTLY ON THE ORDER OF A TENTH...MAYBE TWO TENTHS AT MOST.
WITH SNOW TO WATER RATIOS LIKELY IN THE 10-15 TO 1 RANGE AND
DURING THE DAY WHEN THE SUN CAN HAVE SOME IMPACT ON LIMITING
ACCUMULATIONS...THINKING MOSTLY UP TO 1 INCH OF SNOWFALL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 307 PM CST SUN DEC 1 2013
MAIN LONG TERM FORECAST CONCERNS ARE PRECIPITATION CHANCES AND
TEMPERATURES THROUGH WEDNESDAY...THEN TEMPERATURES BEYOND THAT
AS ARCTIC AIR BEGINS TO FLOW IN.
THE BIGGEST ISSUE TO THE FORECAST IS THE EVOLUTION OF THE
TROUGHING THAT DROPS INTO THE PACIFIC NORTHWEST AND NORTHERN
ROCKIES ON MONDAY. GOOD MODEL CONSENSUS EXISTS THAT THE WESTERN
PART OF THE TROUGH IS GOING TO DIG DEEPLY THROUGH THE WESTERN
U.S.. THE EASTERN PART OF THE TROUGH...ON THE OTHER
HAND...DIFFERENCES SHOW UP WHICH HAVE HUGE IMPLICATIONS TO THE
FORECAST. THE 01.12Z NAM HAS THE EASTERN PORTION OF THE TROUGH
MOVING INTO THE DAKOTAS ON TUESDAY AS A CLOSED LOW...WHEREAS THE
01.12Z GFS/ECMWF/CANADIAN STILL HOLD IT BACK IN SOUTHWEST MONTANA.
THUS...THE NAM EXITS PRECIP THE QUICKEST COME WEDNESDAY AND BEGINS
THE FLOW OF ARCTIC AIR IN THE EARLIEST. BASED ON AVAILABLE MODEL
GUIDANCE...HAVE MOSTLY DISCOUNTED THE NAM AS AN OUTLIER. OF THE
01.12Z GFS/ECMWF/CANADIAN...THE GFS BECOMES THE NEXT FASTEST OF
EXITING THE PRECIPITATION AND BRINGING THE COLD AIR ON
WEDNESDAY...RESULTING FROM MOVING THE UPPER LOW OUT TO THE EAST
QUICKER. HARD TO SAY WHICH OF THIS MODEL GROUP IS CORRECT.
HOWEVER...ITS WORTH NOTING THAT THE ECMWF/CANADIAN HAVE SPED UP
FROM YESTERDAY...REGARDING THE UPPER LOW...EXITING THE
PRECIPITATION AND BRINGING IN THE COLD AIR. THUS...THE FORECAST
FOR MONDAY NIGHT THROUGH WEDNESDAY TAKES A BLEND OF THE
GFS/ECMWF/CANADIAN AND CONTINUITY.
FOR MUCH OF MONDAY NIGHT THROUGH TUESDAY NIGHT...THE FORECAST
AREA REMAINS IN THAT 280-295K ISENTROPIC LIFT ZONE LEFTOVER FROM
MONDAY. THE STRONGEST OF THE LIFT OVERALL STAYS CENTERED NORTH OF
I-90. PRECIPITATION CHANCES INCREASE BECAUSE MOISTURE CONTINUES TO
INCREASE AND DEEPEN. PRECIPITABLE WATER INCREASES FROM NEAR 0.5
INCH ON MONDAY TO 0.6-0.7 INCHES ON TUESDAY. WARMER AIR FLOWING IN
ON SOUTH TO SOUTHEAST 925-850MB WINDS SHOULD ALLOW PRECIPITATION
THAT IS A SNOW OR RAIN/SNOW MIX MONDAY NIGHT INTO TUESDAY MORNING
TO SWITCH MOSTLY OVER TO ALL RAIN BY TUESDAY AFTERNOON. THE ONE
EXCEPTION TO THIS IS OVER TAYLOR COUNTY WHICH IS FARTHEST FROM THE
WARMER AIR ADVECTING IN FROM THE SOUTH. WEDNESDAY IS VERY TRICKY
WITH TEMPERATURES AND PRECIPITATION CHANCES...AS IT HIGHLY DEPENDS
ON THE TIMING OF THE UPPER LOW AND AN EXPECTED COLD FRONTAL
PASSAGE. TEMPERATURES COULD EITHER BE IN THE MID 30S - LOW 40S OR
MID 20S - LOW 30S...WHICH OF COURSE GREATLY AFFECTS PRECIPITATION
TYPE. AS MENTIONED EARLIER...STUCK WITH A COMPROMISE.
SINCE THE LIFT OVERALL IS WEAK FOR MUCH OF THE MONDAY NIGHT
THROUGH WEDNESDAY TIME PERIOD...MUCH OF THE PRECIPITATION SHOULD
BE ON THE LIGHT SIDE. TAYLOR COUNTY AGAIN AS THE GREATEST SHOT OF
SEEING SNOW...BUT WITH THE LIGHT ASPECT TO THE PRECIPITATION AND
LOWER SNOW TO WATER RATIOS...ACCUMULATIONS SHOULD STAY LESS THAN 1
INCH IN EACH 6 HOUR PERIOD. NOW IF YOU TOTAL THIS UP...SNOWFALL
AMOUNTS BY WEDNESDAY EVENING END UP IN THE 4-6 INCH RANGE...BUT
SETTLING...AND POSSIBLY MIXING WITH RAIN ON TUESDAY AFTERNOON...
PUTS A LOT OF DOUBT FOR NEED OF AN ADVISORY AT THIS TIME.
AFTER WEDNESDAY...ITS ALL ABOUT THE ARCTIC AIR AS A LONGWAVE
TROUGH SETS UP FROM THE SOUTHWESTERN U.S. INTO NORTHERN ONTARIO.
THE MAIN REASON FOR ARCTIC AIR COMING IS A POLAR STREAM UPPER
TROUGH THAT DROPS SOUTH OUT OF CENTRAL CANADA AND PROGRESSES
ACROSS THE UPPER MIDWEST ON FRIDAY. AS THIS POLAR TROUGH
APPROACHES...850MB/925MB TEMPS JUST GRADUALLY DROP RIGHT THROUGH
FRIDAY. BY 00Z SATURDAY...850MB STANDARDIZED ANOMALIES ARE DOWN TO
-2.5. IF WE CAN GET SOME SNOW ON WEDNESDAY...EVEN 1 INCH TO STAY
ON THE GROUND...TEMPERATURES COULD BE QUITE A BIT COLDER THAN
FORECAST FOR THURSDAY THROUGH SATURDAY. DOES NOT LOOK LIKE ANY
REAL MEASURABLE SNOW THREAT UNTIL SUNDAY AT THE EARLIEST...AND
THATS IF THE ECMWF IS CORRECT IN TIMING OF BRINGING OUT A
STRONGER WAVE OUT OF THE WESTERN TROUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1146 AM CST SUN DEC 1 2013
AS WEAK WARM AIR ADVECTION DEVELOPS ACROSS THE AREA THIS
AFTERNOON A BROKEN 8-10K FOOT DECK OF CLOUDS WILL SPREAD ACROSS
THE AREA. THESE CLOUDS HAVE ALREADY MOVED INTO KRST AND WILL MOVE
INTO KLSE AROUND 01.21Z. THESE CLOUDS WILL GRADUALLY DROP INTO THE
4 TO 8K RANGE OVERNIGHT...AND THEN KRST WILL SEE A BKN015 DECK
DEVELOP AROUND 02.16Z.
WITH THE MODELS CONTINUING TO STRUGGLE ON WHERE THE PRECIPITATION
WILL OCCUR...DID NOT INCLUDE THEM IN EITHER TAF SITE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 220 PM CST SUN DEC 1 2013
SEVERAL FORECAST ISSUES THIS PERIOD INCLUDING SOUTHERN EXTENT OF
LOW CLOUDS OVERNIGHT...WHETHER LAKE EFFECT SNOW SHOWERS AFFECT
DOOR COUNTY...AND TIMING OF NEXT SYNOPTIC-SCALE SYSTEM.
WEAK LOW-LEVEL WAA TONIGHT AS WINDS BECOME SW-W. AS A RESULT
WOULD EXPECT THE LOW CLOUDS TO STICK AROUND OVER MUCH OF THE
AREA. DIURNAL CU THAT FORMED ALONG SOUTHERN EXTENT OF LOW CLOUDS
MAY DISSIPATE BUT HIGHER CLOUDS UPSTREAM MOVING IN.
REPEATED RUNS OF HRRR AND OTHER SHORT-TERM MODELS INDICATE SOME
LAKE EFFECT SNOW SHOWERS ASSOCIATED WITH POSSIBLE MESOVORTEX OVER
NORTH-CENTRAL LK MICHIGAN TONIGHT WHICH COULD CLIP DOOR COUNTY.
DELTA-T`S ARE MARGINAL BUT WILL CONTINUE WITH SMALL CHANCE OF
SNOW SHOWERS OR FLURRIES IN NORTHERN DOOR. MIN TEMPS SHOULD DROP
INTO THE 20S MOST AREAS AWAY FROM LK MICHIGAN.
ON MONDAY...WAA INCREASES AS NEXT SYSTEM APPROACHES FROM THE
WEST. SOME LIGHT SNOW OR FLURRIES EXPECTED TO MOVE INTO AT LEAST
THE WESTERN HALF OF THE AREA BY LATE AFTERNOON. STILL SOME
QUESTION AS TO HOW FAST SYSTEM BEGINS TO AFFECT AREA...SO WILL
CONTINUE TO USE MODEL BLEND WHICH RESULTS IN TIMING SIMILAR TO
PREVIOUS FORECAST. HIGH TEMP FORECAST A BLEND OF BEST PERFORMING
MOS GUIDANCE WHICH IS NOT FAR OFF FROM PREVIOUS FORECAST.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 220 PM CST SUN DEC 1 2013
A VERY CHALLENGING FORECAST PERIOD THROUGH MID WEEK DUE TO
TIMING ISSUES WITH A DEVELOPING STORM SYSTEM AND PCPN TYPE. THE
POTENTIAL EXISTS FOR WINTER HEADLINES OVER NORTH CENTRAL WISCONSIN
FOR MAINLY SNOW.
STARTING MONDAY NIGHT...NAM AND GFS CONTINUE TO REMAIN A BIT QUICKER
WITH SPREADING THE BAND OF SNOW OVER THE AREA FASTER WITH THE WARM
AIR ADVECTION. OLD ECMWF IS ABOUT 12 HOURS SLOWER WHILE THE GEM
WAS THE AVERAGE. LATEST ECMWF IS CLOSER TO THE GEM TIME WITH THE
INITIAL WAA TOWARD MONDAY NIGHT.
AVAILABLE FORECAST SOUNDINGS DO INDICATE SNOW AT THE START FOR
THE PCPN TYPE WITH AROUND AN INCH OR TWO OF ACCUMULATION BY
TUESDAY MORNING...WITH THE 2 INCH AMOUNTS TOWARD CENTRAL AND NORTH
CENTRAL AND POINTS NORTHWEST. THE AIR COLUMN LIKELY WILL REMAIN
COLD ENOUGH FOR SNOW FOR ANOTHER 2 INCHES ACROSS THE NORTH. ITS
POSSIBLE AN ADVISORY WILL BE NEEDED FOR NORTH CENTRAL AND PARTS OF
FAR NORTHEAST WISCONSIN FOR THIS INITIAL BAND. SNOW AMOUNTS APPEAR
TO DIMINISH DUE TO CONTINUED WAA AND PCPN CHANGING TO RAIN OR A
RAIN SNOW MIX. THE NAM FORECAST SOUNDING FOR RHI CHANGES THE SN
OVER BRIEFLY ZR THEN RAIN TUESDAY NIGHT THEN BACK TO SNOW LATE.
WITH FROST DEPTHS A FEW INCHES DEEP OVER MANY LOCATIONS DUE TO THE
COLD LATER HALF OF NOVEMBER...POTENTIAL OF BRIEF PERIOD ICY ROADS
DUE TO ZR AND COLD GROUND. NOT CONFIDENT OF THE ZR AT THIS TIME
BUT IF THIS BECOMES MORE OF A THREAT...WINTER WEATHER ADVISORIES
MAY BE NEEDED FOR THAT ELEMENT ALONE TOWARD TUESDAY AS WELL.
BLEND OF MEDIUM RANGE MODELS WITH THE H850 LOW TRACKS SUGGESTS THE
SYSTEM PCPN/SNOW TO REMAIN NORTHWEST OF THE AREA BUT CLOSE ENOUGH
TO PRODUCE ANOTHER INCH OR TWO OVER NORTH CENTRAL WISCONSIN. AT
THIS TIME...UP TO 6 INCHES OF SNOW POSSIBLE OVER PARTS OF NORTH
CENTRAL WISCONSIN FROM MONDAY NIGHT INTO WEDNESDAY MORNING. BUT
DUE TO THE SNOW AMOUNTS WILL BE SPREAD OVER A 36-48 PERIOD...NO
WATCH ISSUED AT THIS TIME. ANTICIPATE A LONG DURATION ADVISORY OR
TWO SHORTER WINTER ADVISORIES MAY BE NEEDED TO HANDLE THE SNOW
ACCUMULATION AND OR MIX CLOSER TO THE EVENT.
BITTERLY COLD ARCTIC AIR WILL THEN POUR INTO THE ARE IN THE WAKE
OF THE SYSTEM. WITH NEED TO HAVE A HEALTHY NORTH TO SOUTH GRADIENT
IN TEMPS LATER IN THE WEEK DUE TO THE COLDER TEMPERATURES OVER
THE ANTICIPATED SNOW COVER OVER NORTH CENTRAL WISCONSIN TO
PROBABLY LITTLE OR NO SNOW OVER CENTRAL AND EAST CENTRAL
WISCONSIN. WINDS APPEAR TO WESTERLY FOR SIGNIFICANT LAKE EFFECT
SNOWS TO REACH FAR NORTH CENTRAL WISCONSIN DURING THE ARTIC SURGE.
MEDIUM RANGE RUNS BEGIN TO DEVELOP RETURN FLOW PCPN AGAIN LATE
NEXT WEEKEND AND FOR THE START OF THE NEXT WEEK...WILL KEEP THE
FORECAST DRY THROUGH NEXT WEEKEND FOR NOW.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1206 PM CST SUN DEC 1 2013
MVFR CIGS ACROSS MUCH OF FORECAST AREA DURING PERIOD. ISOLATED
IFR CIGS NOTED IN VILAS COUNTY FROM TIME TO TIME. GENERALLY MVFR
CIGS EXPECTED BEFORE MUCH LOWER CIGS AND VSBYS ARRIVE LATE MONDAY
AND EARLY TUESDAY ASSOCIATED WITH NEXT STORM SYSTEM.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....JKL
LONG TERM......TDH
AVIATION.......JKL
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1146 AM CST SUN DEC 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 335 AM CST SUN DEC 1 2013
THE MAIN FOCUS IS ON THE INCREASING CHANCES FOR SNOW
TONIGHT...MAINLY IN SOUTHEAST MINNESOTA...NORTHEAST IOWA AND FAR
WESTERN WISCONSIN.
CURRENTLY...NORTHWESTERLY FLOW ALOFT IS IN PLACE WITH A SURFACE
RIDGE OF HIGH PRESSURE CENTERED ON THE EASTERN DAKOTAS. THE
INITIAL QUESTION THIS MORNING IS WITH A STRATUS DECK THAT EXTENDS
ACROSS NORTHERN WISCONSIN/MINNESOTA AND HOW FAR SOUTH IT WILL MAKE
IT TODAY. THERE HAS NOT BEEN MUCH OF A SOUTHERLY PUSH WITH IT OVER
THE PAST 6 HOURS OR SO...EXCEPT IN EASTERN WISCONSIN ALONG LAKE
MICHIGAN. THE PAST FEW RUNS OF THE HRRR SHOW THIS STRATUS DECK
HAVING TROUBLE MAKING IT SOUTH TODAY AS THE RIDGE OF HIGH PRESSURE
COMES IN AND WEAKENS THE NORTHERLY SURFACE FLOW. IF THIS DECK DOES
MAKE IT FURTHER SOUTH...IT WILL CAUSE TEMPERATURES TO BE ABOUT
5-10F COOLER FOR HIGHS.
GOING INTO TONIGHT...A LEAD/WEAK MID LEVEL SHORT WAVE TROUGH WILL
PROPAGATE EAST ACROSS THE NORTHERN PLAINS WHILE ISENTROPIC LIFT ON
THE 290K SURFACE INCREASES. THIS SHOULD PROVIDE ENOUGH
LIFT...ALBEIT WEAK...TO DEVELOP A BAND OF LIGHT SNOW FROM CENTRAL
MINNESOTA DOWN ALONG THE MISSISSIPPI RIVER. ANY ACCUMULATIONS
OVERNIGHT WILL BE ON THE LIGHT SIDE AT A FEW TENTHS OF AN INCH OR
LESS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 335 AM CST SUN DEC 1 2013
LIFT AND MOISTURE WILL BECOME DEEPER MONDAY INTO WEDNESDAY AS THE
CORE OF THE MID LEVEL TROUGH APPROACHES THE REGION. FOR
MONDAY...THE MAIN FOCUS CONTINUES TO BE ALONG THE NOSE OF THE LOW
LEVEL WARM AIR ADVECTION AND WHERE IT WILL SET UP. ALL OF THE
01.00Z GUIDANCE SHOW THE BAND OF PRECIPITATION EXPANDING THROUGH
THE DAY AS THIS ADVECTION STRENGTHENS. HOWEVER...AS WARMER AIR
COMES IN AT THE LOW LEVELS...SOME PRECIPITATION TYPE ISSUES ARISE
WITH THE WARM LAYER POSSIBLY CAUSING THE SNOW TO CHANGE OVER TO
RAIN. SURFACE TEMPERATURES SHOULD ALSO BE ON THE RISE ABOVE
FREEZING...SO AM NOT EXPECTING ANY FREEZING RAIN AT THE MOMENT.
THERE IS SOME UNCERTAINTY TOO WITH THE POSITION OF THE NORTHWEST
TO SOUTHEAST SWATH OF PRECIPITATION WITH THE 01.00Z NAM/01.03Z
SREF BEING THE FARTHEST NORTHEAST WHILE THE 01.00Z GFS/ECMWF
DEVELOP IS MORE TO THE SOUTHWEST IN SOUTHEAST MINNESOTA/NORTHEAST
IOWA. MAY BE UNDER-DOING THE SNOW AMOUNTS ON MONDAY...BUT THE
POTENTIAL MIX HAS ME CAUTIOUS TO GO MUCH ABOVE A FEW TENTHS OF AN
INCH.
THE BIGGEST STORY WITH THE 01.00Z GUIDANCE IS HOW THEY HAVE ALL
COME AROUND TO THIS THINKING OF A MUCH FASTER FRONTAL PASSAGE WITH
THE DEEPENING SURFACE LOW/MID LEVEL TROUGH MOVING THROUGH EARLY ON
WEDNESDAY. THE BEST CHANCES FOR ANY PRECIPITATION APPEARS TO BE
FROM MONDAY NIGHT THROUGH WEDNESDAY AS THIS TROUGH APPROACHES. THE
WARMER AIR COMING IN ON TUESDAY AHEAD OF THE SYSTEM SHOULD KEEP
THE P-TYPE MAINLY AS RAIN UNTIL THE COLD FRONT COMES THROUGH EARLY
ON WEDNESDAY. THE MAIN CHANCES FOR SNOW WILL BE ON MONDAY NIGHT
AHEAD OF THE WARM AIR..AND THEN AGAIN ON WEDNESDAY MORNING BETWEEN
THE LEAD COLD FRONT PASSAGE AND THE SECONDARY COLD FRONT WHICH
USHERS IN THE DRASTICALLY COLDER AIR IN. OVERALL...CONFIDENCE IN
GETTING ANY SPECIFIC DETAILS DOWN ON THE PRECIPITATION TRENDS IS
PRETTY LOW...PARTICULARLY WITH THE SNOW AMOUNTS. IF ANY SNOW IS
ABLE TO OCCUR WEDNESDAY MORNING AFTER THE FIRST FRONT COMES
THROUGH...IT WILL MEAN THAT TEMPERATURES COULD BE COLDER THAN
ADVERTISED GOING THROUGH THE REST OF THE WEEK. DUE TO THE FASTER
FROPA...HAVE DROPPED THE PRECIPITATION CHANCES FROM THURSDAY
INTO THE WEEKEND.
AS FOR THE COLD SPELL...850MB TEMPERATURES ARE FORECAST TO DROP
DOWN TO BETWEEN -15 TO -20C ON THURSDAY WITH THE POOL OF COLD AIR
LASTING THROUGHOUT THE REGION PAST NEXT WEEKEND. EVEN IF THERE IS
NO SNOW COVER DOWN ON THE GROUND...TEMPERATURES WILL BE MUCH
BELOW NORMAL THROUGH THE FORESEEABLE FUTURE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1146 AM CST SUN DEC 1 2013
AS WEAK WARM AIR ADVECTION DEVELOPS ACROSS THE AREA THIS
AFTERNOON A BROKEN 8-10K FOOT DECK OF CLOUDS WILL SPREAD ACROSS
THE AREA. THESE CLOUDS HAVE ALREADY MOVED INTO KRST AND WILL MOVE
INTO KLSE AROUND 01.21Z. THESE CLOUDS WILL GRADUALLY DROP INTO THE
4 TO 8K RANGE OVERNIGHT...AND THEN KRST WILL SEE A BKN015 DECK
DEVELOP AROUND 02.16Z.
WITH THE MODELS CONTINUING TO STRUGGLE ON WHERE THE PRECIPITATION
WILL OCCUR...DID NOT INCLUDE THEM IN EITHER TAF SITE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION...BOYNE
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1101 AM CST SUN DEC 1 2013
.UPDATE...
CLOUDS OVER THE LAKE ARE GRADUALLY SWINGING WESTWARD ONTO THE
SHORELINE. RAP AND NAM 1000-850MB WIND DIRECTION AND RH DEPICT THIS
WELL. AT THIS TIME...THE CLOUDS APPEAR TO BE MIXING OUT A LITTLE
OVER LAND. EXPECTING THE CLOUDS TO PUSH A LITTLE FURTHER INLAND
LATER THIS AFTERNOON AS FLOW TURNS NNE.
TEMPERATURES ARE A LITTLE TRICKY TODAY. THEY ARE ALREADY CLOSE TO
REACHING THE FCST MAX TEMP...BUT 925MB TEMPS WILL REMAIN STEADY
AROUND -3C TODAY. THEREFORE...WILL LEAVE MAX TEMPS ALONE...IN THE
UPPER 30S.
&&
.AVIATION/18Z TAFS/...
LAKE CLOUDS ARE STARTING TO SHIFT WESTWARD ONTO THE SOUTHEAST WI
SHORELINE. CIGS ARE 1400-2500 FEET. EXPECT THESE TO AFFECT MKE...RAC
AND ENW THROUGH MUCH OF THE AFTERNOON.
FLOW IS EXPECTED TO SHIFT NORTHEAST THEN EAST TONIGHT SO STRATUS
FROM NORTHERN WI AND OVER THE LAKE ARE EXPECTED TO SPREAD INTO
SOUTHEAST WI AND POSSIBLY SOUTH CENTRAL WI TONIGHT. UNCERTAINTY
ABOUT CLOUD BASES...BUT PLANNING ON VFR INLAND AND MVFR NEAR THE
SHORELINE FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 330 AM CST SUN DEC 1 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH
NAM BRINGS STRATUS FIELD OVER EAST CENTRAL WI SWD THROUGH ERN WI AND
OVER LAKE MI THROUGH THE MORNING. ONCE ESTABLISHED IT WILL LIKELY BE
DIFFICULT TO ERODE ESPECIALLY NEAR LAKE MI DUE TO THE DEVELOPING
INSTABILITY OVER LAKE MI. THE INSTABILITY OVER THE LAKE WILL
CONTRIBUTE TO CLOUDS BUT NOT ENOUGH FOR PCPN. OVER SOUTH CENTRAL
WI...WILL BE EXPECTING A PARTLY CLOUDY AND NICE DAY...HOWEVER THE
WESTERN EXTENT OF THE EXPECTED STRATUS IS UNCERTAIN. HIGH PRESSURE
CURRENTLY MOVING INTO MN WILL ARRIVE BY THIS EVENING. MIDDLE TO HIGH
CLOUDS TO THEN INCREASE TONIGHT AS A SHORTWAVE TROUGH APPROACHES
FROM THE WEST. NO PCPN IS EXPECTED UNTIL MONDAY OR MONDAY NIGHT.
TEMPS NEAR NORMAL TODAY AND ABOVE NORMAL FOR TNT GIVEN EXPECTED
CLOUDS.
MONDAY - CONFIDENCE...MEDIUM
SUBSIDING INFLUENCE OF HIGH DRIFTS EAST WITH DEVELOPING WAA. WEAK
WAVE IN THE FLOW STILL GENERATED LIGHT QPF ON THE 12Z ECMWF IN THE
FAR SE. HOWEVER 00Z RUN HAS DRIED IT OUT CONVERTING WI DURING THE
MORNING SO WILL RETAIN SOME SMALL POPS FOR THIS. HOWEVER GFS AND
NAM BOTH DRY AND ECMWF APPEARS TO BE A LITTLE LESS IMPRESSIVE WITH
THIS. STILL WORTH A MENTION NONETHELESS. DURING THE AFTERNOON THE
00Z NAM AND 00Z GFS SHOW A PRONOUNCED UPSWING IN ISENTROPIC LIFT
INTO SRN WI...ESP SC WI. THE ECMWF IS SLOWER ON ERODING THE LOW
LEVEL THERMAL TROUGH AND SHOWS ALL QPF TIED TO THIS LIFT ACROSS IA
AND MN. THE GFS IS THE COMPROMISE APPROACH KEEPING THE BETTER
POTENTIAL ACROSS THE WESTERN CWA.
MONDAY NIGHT - CONFIDENCE...LOW TO MEDIUM
WARM AIR ADVECTION CONTINUES THIS PERIOD. THE 00Z NAM AND 00Z GFS
ARE MORE AGGRESSIVE WITH LIFTING THE WARMER TEMPERATURES NORTH.
MEANWHILE THE 12Z ECMWF SUGGESTS A SLOWER ARRIVAL OF THE WAA
PRECIP WITH THE COLDER PROFILE LINGERING LONGER. THE 00Z HAS
WARMED UP SOME BUT NOT AS MUCH AS THE NAM AND GFS SUGGEST.
TUESDAY - CONFIDENCE...MEDIUM
00Z NAM AND 00Z GFS BOTH SHOW WARM CONVEYOR WELL ENTRENCHED AHEAD
OF THE PLAINS LOW. 12Z ECMWF SHOWED A SLOWER SOLUTION WITH 850
TEMPS 5-8 DEGREES COLDER AND STILL IMPLYING A LINGERING MIX
POTENTIAL WHILE GFS AND NAM CLEARLY FAVOR ALL RAIN. THE NEW 00Z
ECMWF HAS WARMED CONSIDERABLY CONVERGING ON THE NAM AND GFS
SOLUTION. SO WILL TREND ANY MIX OVER TO RAIN FOR THE AFTERNOON.
WEDNESDAY AND WEDNESDAY NIGHT - CONFIDENCE...LOW
WHILE THE 00Z ECMWF HAS TRENDED FASTER ON THE FRONTAL
TIMING...THE GFS STILL REMAINS MUCH QUICKER WITH COLD ADVECTION
WELL UNDERWAY. THE ECMWF AND NAM SHOW THE MILD AIR LINGERING AT
LEAST THROUGH THE MORNING BEFORE THE FRONT ARRIVES TOWARDS MIDDAY.
SO HIGHS MAY END UP BEING IN THE MORNING PRIOR TO FRONTAL PASSAGE.
HOWEVER IF THE TREND OF THE ECMWF PLAYING CATCHUP TO THE GFS
CONTINUES...THEN THE DAY COULD END UP STARTING ON THE CHILLY SIDE.
FOR NOW WILL LEAN TO THE WARM WEDGE AT LEAST HAVING A SAY FOR A
PART OF THE DAY. 00Z ECMWF DOES SHOW SOME LIGHT SNOW POTENTIAL
WEDNESDAY NIGHT WITH SECONDARY FEATURE WITH AN UPTICK IN 700-300
MILLIBAR Q-VECTOR CONVERGENCE SO WILL RETAIN A SMALL CHANCE OF -SN
FOR WEDNESDAY NIGHT.
THURSDAY THROUGH SATURDAY - CONFIDENCE...MEDIUM
STEADY COLD ADVECTION FOR THIS PERIOD. COLDEST AIR ARRIVES
SATURDAY WITH 925 TEMPS -15 TO -20C. MOST OF THE CWA LOOKS TRAPPED
IN THE TEENS FOR HIGHS ON SATURDAY.
AVIATION/12Z TAFS/...STRATUS FIELD WITH CIGS OF 1.0-3.0 KFT
CONTINUES TO MOVE STEADILY SWD FROM NE WI INTO EAST CENTRAL WI. THE
NAM DOES BRING THE STRATUS FIELD INTO EAST CENTRAL AND SE WI FOR
TODAY AND TNT AND FOLLOWED THIS SCENARIO. LESS UNCERTAINTY OVER
SOUTH CENTRAL WI SINCE STRATUS HAS HALTED OVER CENTRAL AND NW WI AND
MODELS INDICATE A MUCH LOWER POTENTIAL OF STRATUS THERE. WILL GO
WITH FEW-SCT STRATUS AT KMSN THROUGH THE PERIOD.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
MONDAY THROUGH SATURDAY...COLLAR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
538 AM CST SUN DEC 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 335 AM CST SUN DEC 1 2013
THE MAIN FOCUS IS ON THE INCREASING CHANCES FOR SNOW
TONIGHT...MAINLY IN SOUTHEAST MINNESOTA...NORTHEAST IOWA AND FAR
WESTERN WISCONSIN.
CURRENTLY...NORTHWESTERLY FLOW ALOFT IS IN PLACE WITH A SURFACE
RIDGE OF HIGH PRESSURE CENTERED ON THE EASTERN DAKOTAS. THE
INITIAL QUESTION THIS MORNING IS WITH A STRATUS DECK THAT EXTENDS
ACROSS NORTHERN WISCONSIN/MINNESOTA AND HOW FAR SOUTH IT WILL MAKE
IT TODAY. THERE HAS NOT BEEN MUCH OF A SOUTHERLY PUSH WITH IT OVER
THE PAST 6 HOURS OR SO...EXCEPT IN EASTERN WISCONSIN ALONG LAKE
MICHIGAN. THE PAST FEW RUNS OF THE HRRR SHOW THIS STRATUS DECK
HAVING TROUBLE MAKING IT SOUTH TODAY AS THE RIDGE OF HIGH PRESSURE
COMES IN AND WEAKENS THE NORTHERLY SURFACE FLOW. IF THIS DECK DOES
MAKE IT FURTHER SOUTH...IT WILL CAUSE TEMPERATURES TO BE ABOUT
5-10F COOLER FOR HIGHS.
GOING INTO TONIGHT...A LEAD/WEAK MID LEVEL SHORT WAVE TROUGH WILL
PROPAGATE EAST ACROSS THE NORTHERN PLAINS WHILE ISENTROPIC LIFT ON
THE 290K SURFACE INCREASES. THIS SHOULD PROVIDE ENOUGH
LIFT...ALBEIT WEAK...TO DEVELOP A BAND OF LIGHT SNOW FROM CENTRAL
MINNESOTA DOWN ALONG THE MISSISSIPPI RIVER. ANY ACCUMULATIONS
OVERNIGHT WILL BE ON THE LIGHT SIDE AT A FEW TENTHS OF AN INCH OR
LESS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 335 AM CST SUN DEC 1 2013
LIFT AND MOISTURE WILL BECOME DEEPER MONDAY INTO WEDNESDAY AS THE
CORE OF THE MID LEVEL TROUGH APPROACHES THE REGION. FOR
MONDAY...THE MAIN FOCUS CONTINUES TO BE ALONG THE NOSE OF THE LOW
LEVEL WARM AIR ADVECTION AND WHERE IT WILL SET UP. ALL OF THE
01.00Z GUIDANCE SHOW THE BAND OF PRECIPITATION EXPANDING THROUGH
THE DAY AS THIS ADVECTION STRENGTHENS. HOWEVER...AS WARMER AIR
COMES IN AT THE LOW LEVELS...SOME PRECIPITATION TYPE ISSUES ARISE
WITH THE WARM LAYER POSSIBLY CAUSING THE SNOW TO CHANGE OVER TO
RAIN. SURFACE TEMPERATURES SHOULD ALSO BE ON THE RISE ABOVE
FREEZING...SO AM NOT EXPECTING ANY FREEZING RAIN AT THE MOMENT.
THERE IS SOME UNCERTAINTY TOO WITH THE POSITION OF THE NORTHWEST
TO SOUTHEAST SWATH OF PRECIPITATION WITH THE 01.00Z NAM/01.03Z
SREF BEING THE FARTHEST NORTHEAST WHILE THE 01.00Z GFS/ECMWF
DEVELOP IS MORE TO THE SOUTHWEST IN SOUTHEAST MINNESOTA/NORTHEAST
IOWA. MAY BE UNDER-DOING THE SNOW AMOUNTS ON MONDAY...BUT THE
POTENTIAL MIX HAS ME CAUTIOUS TO GO MUCH ABOVE A FEW TENTHS OF AN
INCH.
THE BIGGEST STORY WITH THE 01.00Z GUIDANCE IS HOW THEY HAVE ALL
COME AROUND TO THIS THINKING OF A MUCH FASTER FRONTAL PASSAGE WITH
THE DEEPENING SURFACE LOW/MID LEVEL TROUGH MOVING THROUGH EARLY ON
WEDNESDAY. THE BEST CHANCES FOR ANY PRECIPITATION APPEARS TO BE
FROM MONDAY NIGHT THROUGH WEDNESDAY AS THIS TROUGH APPROACHES. THE
WARMER AIR COMING IN ON TUESDAY AHEAD OF THE SYSTEM SHOULD KEEP
THE P-TYPE MAINLY AS RAIN UNTIL THE COLD FRONT COMES THROUGH EARLY
ON WEDNESDAY. THE MAIN CHANCES FOR SNOW WILL BE ON MONDAY NIGHT
AHEAD OF THE WARM AIR..AND THEN AGAIN ON WEDNESDAY MORNING BETWEEN
THE LEAD COLD FRONT PASSAGE AND THE SECONDARY COLD FRONT WHICH
USHERS IN THE DRASTICALLY COLDER AIR IN. OVERALL...CONFIDENCE IN
GETTING ANY SPECIFIC DETAILS DOWN ON THE PRECIPITATION TRENDS IS
PRETTY LOW...PARTICULARLY WITH THE SNOW AMOUNTS. IF ANY SNOW IS
ABLE TO OCCUR WEDNESDAY MORNING AFTER THE FIRST FRONT COMES
THROUGH...IT WILL MEAN THAT TEMPERATURES COULD BE COLDER THAN
ADVERTISED GOING THROUGH THE REST OF THE WEEK. DUE TO THE FASTER
FROPA...HAVE DROPPED THE PRECIPITATION CHANCES FROM THURSDAY
INTO THE WEEKEND.
AS FOR THE COLD SPELL...850MB TEMPERATURES ARE FORECAST TO DROP
DOWN TO BETWEEN -15 TO -20C ON THURSDAY WITH THE POOL OF COLD AIR
LASTING THROUGHOUT THE REGION PAST NEXT WEEKEND. EVEN IF THERE IS
NO SNOW COVER DOWN ON THE GROUND...TEMPERATURES WILL BE MUCH
BELOW NORMAL THROUGH THE FORESEEABLE FUTURE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 538 AM CST SUN DEC 1 2013
LOWER LEVEL MOISTURE/MVFR STRATUS DECK THAT WAS HEADED TOWARD THE
AREA FROM NORTHERN MN/WI LAST EVENING HAS STALLED EARLY THIS
MORNING...LOOKING TO STRUGGLE WITH THE DOWN-SLOPING NORTH/NORTHEAST
FLOW FROM THE NORTHERN HIGHLAND TERRAIN OF WI. SFC-925MB WINDS FOR
ANY ADVECTION OF THIS MOISTURE/CLOUDS BECOMES LIGHT/VARIABLE TODAY.
HAVE LIMITED LOWER CLOUDS FOR TODAY TO SCT DIURNAL IN THE 2000-2500
FT RANGE DURING THE 17Z-22Z PERIOD. SFC/LOW LEVEL RIDGE AXIS PASSES
THIS EVENING WITH LOWER LEVEL WARM ADVECTION/INCREASING 850-500MB
MOISTURE SPREADING INTO THE AREA. CLOUD DECKS TO THICKEN/LOWER LATE
THIS AFTERNOON/TONIGHT AS THE MOISTURE/SOME LIFTING ARRIVE. MODEL
SIGNAL IS BECOMING MORE CONSISTENT THAT ENOUGH MOISTURE/LIFT WILL BE
PRESENT FOR SOME -SN WEST OF THE MS RIVER LATER TONIGHT. ADDED A
VCSH AFTER 05Z AT KRST FOR NOW AS APPEARS ANY LATE NIGHT -SN WOULD
BE QUITE LIGHT. LEFT CIGS LATER TONIGHT VFR AS WELL...AS BULK OF THE
MOISTURE/CLOUD INCREASE AND LIFTING IS ABOVE 850MB.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
335 AM CST SUN DEC 1 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 335 AM CST SUN DEC 1 2013
THE MAIN FOCUS IS ON THE INCREASING CHANCES FOR SNOW
TONIGHT...MAINLY IN SOUTHEAST MINNESOTA...NORTHEAST IOWA AND FAR
WESTERN WISCONSIN.
CURRENTLY...NORTHWESTERLY FLOW ALOFT IS IN PLACE WITH A SURFACE
RIDGE OF HIGH PRESSURE CENTERED ON THE EASTERN DAKOTAS. THE
INITIAL QUESTION THIS MORNING IS WITH A STRATUS DECK THAT EXTENDS
ACROSS NORTHERN WISCONSIN/MINNESOTA AND HOW FAR SOUTH IT WILL MAKE
IT TODAY. THERE HAS NOT BEEN MUCH OF A SOUTHERLY PUSH WITH IT OVER
THE PAST 6 HOURS OR SO...EXCEPT IN EASTERN WISCONSIN ALONG LAKE
MICHIGAN. THE PAST FEW RUNS OF THE HRRR SHOW THIS STRATUS DECK
HAVING TROUBLE MAKING IT SOUTH TODAY AS THE RIDGE OF HIGH PRESSURE
COMES IN AND WEAKENS THE NORTHERLY SURFACE FLOW. IF THIS DECK DOES
MAKE IT FURTHER SOUTH...IT WILL CAUSE TEMPERATURES TO BE ABOUT
5-10F COOLER FOR HIGHS.
GOING INTO TONIGHT...A LEAD/WEAK MID LEVEL SHORT WAVE TROUGH WILL
PROPAGATE EAST ACROSS THE NORTHERN PLAINS WHILE ISENTROPIC LIFT ON
THE 290K SURFACE INCREASES. THIS SHOULD PROVIDE ENOUGH
LIFT...ALBEIT WEAK...TO DEVELOP A BAND OF LIGHT SNOW FROM CENTRAL
MINNESOTA DOWN ALONG THE MISSISSIPPI RIVER. ANY ACCUMULATIONS
OVERNIGHT WILL BE ON THE LIGHT SIDE AT A FEW TENTHS OF AN INCH OR
LESS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 335 AM CST SUN DEC 1 2013
LIFT AND MOISTURE WILL BECOME DEEPER MONDAY INTO WEDNESDAY AS THE
CORE OF THE MID LEVEL TROUGH APPROACHES THE REGION. FOR
MONDAY...THE MAIN FOCUS CONTINUES TO BE ALONG THE NOSE OF THE LOW
LEVEL WARM AIR ADVECTION AND WHERE IT WILL SET UP. ALL OF THE
01.00Z GUIDANCE SHOW THE BAND OF PRECIPITATION EXPANDING THROUGH
THE DAY AS THIS ADVECTION STRENGTHENS. HOWEVER...AS WARMER AIR
COMES IN AT THE LOW LEVELS...SOME PRECIPITATION TYPE ISSUES ARISE
WITH THE WARM LAYER POSSIBLY CAUSING THE SNOW TO CHANGE OVER TO
RAIN. SURFACE TEMPERATURES SHOULD ALSO BE ON THE RISE ABOVE
FREEZING...SO AM NOT EXPECTING ANY FREEZING RAIN AT THE MOMENT.
THERE IS SOME UNCERTAINTY TOO WITH THE POSITION OF THE NORTHWEST
TO SOUTHEAST SWATH OF PRECIPITATION WITH THE 01.00Z NAM/01.03Z
SREF BEING THE FARTHEST NORTHEAST WHILE THE 01.00Z GFS/ECMWF
DEVELOP IS MORE TO THE SOUTHWEST IN SOUTHEAST MINNESOTA/NORTHEAST
IOWA. MAY BE UNDER-DOING THE SNOW AMOUNTS ON MONDAY...BUT THE
POTENTIAL MIX HAS ME CAUTIOUS TO GO MUCH ABOVE A FEW TENTHS OF AN
INCH.
THE BIGGEST STORY WITH THE 01.00Z GUIDANCE IS HOW THEY HAVE ALL
COME AROUND TO THIS THINKING OF A MUCH FASTER FRONTAL PASSAGE WITH
THE DEEPENING SURFACE LOW/MID LEVEL TROUGH MOVING THROUGH EARLY ON
WEDNESDAY. THE BEST CHANCES FOR ANY PRECIPITATION APPEARS TO BE
FROM MONDAY NIGHT THROUGH WEDNESDAY AS THIS TROUGH APPROACHES. THE
WARMER AIR COMING IN ON TUESDAY AHEAD OF THE SYSTEM SHOULD KEEP
THE P-TYPE MAINLY AS RAIN UNTIL THE COLD FRONT COMES THROUGH EARLY
ON WEDNESDAY. THE MAIN CHANCES FOR SNOW WILL BE ON MONDAY NIGHT
AHEAD OF THE WARM AIR..AND THEN AGAIN ON WEDNESDAY MORNING BETWEEN
THE LEAD COLD FRONT PASSAGE AND THE SECONDARY COLD FRONT WHICH
USHERS IN THE DRASTICALLY COLDER AIR IN. OVERALL...CONFIDENCE IN
GETTING ANY SPECIFIC DETAILS DOWN ON THE PRECIPITATION TRENDS IS
PRETTY LOW...PARTICULARLY WITH THE SNOW AMOUNTS. IF ANY SNOW IS
ABLE TO OCCUR WEDNESDAY MORNING AFTER THE FIRST FRONT COMES
THROUGH...IT WILL MEAN THAT TEMPERATURES COULD BE COLDER THAN
ADVERTISED GOING THROUGH THE REST OF THE WEEK. DUE TO THE FASTER
FROPA...HAVE DROPPED THE PRECIPITATION CHANCES FROM THURSDAY
INTO THE WEEKEND.
AS FOR THE COLD SPELL...850MB TEMPERATURES ARE FORECAST TO DROP
DOWN TO BETWEEN -15 TO -20C ON THURSDAY WITH THE POOL OF COLD AIR
LASTING THROUGHOUT THE REGION PAST NEXT WEEKEND. EVEN IF THERE IS
NO SNOW COVER DOWN ON THE GROUND...TEMPERATURES WILL BE MUCH
BELOW NORMAL THROUGH THE FORESEEABLE FUTURE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 1115 PM CST SAT NOV 30 2013
BAND OF MID LEVEL CLOUDS CONTINUES TO HANG WEST-EAST ACROSS THE
REGION...MOSTLY 8-12 KFT. HOWEVER...LARGE MVFR STRATUS DECK
CONTINUES TO SINK SOUTHWARD FROM NORTHERN MN/LAKE SUPERIOR. RAP13
FAVORS KEEPING THIS CLOUD DECK TOGETHER...BUT IS ALSO TRENDING
SLOWER WITH REACHING KRST/KLSE...MORE AFTER 15Z NOW. THE GFS/NAM NOT
AS BULLISH ON BRINGING THE MVFR CLOUDS THIS FAR SOUTH...KEEPING MOST
OF THEM TO THE NORTH AND EAST. MEANWHILE THE FOG/STRATUS SATELLITE
IMAGERY SHOWS A LARGE AREA OF STRATUS...WITH CURRENT TIMING EVEN
LATER THAN THE RAP...CLOSER TO 18Z. WILL CONTINUE TO HOLD WITH THE
IDEA THAT THESE MVFR CIGS WILL MAKE IT TO THE KRST/KLSE...BUT WILL
PUSH BACK THE TIMING. SOUNDINGS CONTINUE TO SUGGEST THAT THERE
SHOULD BE ENOUGH MIXING FOR A DIURNAL INCREASE IN CIG HEIGHT BY
18Z...AND POTENTIALLY BECOME SCT AS DRY AIR MIXES IN.
CLOUD FORECAST REMAINS TOUGH. TRENDS WILL HAVE TO BE MONITORED
CLOSELY AND ADJUSTMENTS MADE AS NECESSARY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
337 AM MST SUN DEC 1 2013
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 337 AM MST SUN DEC 1 2013
WEATHER PATTERN CHANGE BEGINNING TO START TODAY. FORECAST
CHALLENGES DEAL WITH A HIGH WIND EVENT STARTING TODAY AND
PERSISTING THROUGH TUESDAY MORNING.
CURRENTLY...CONDITIONS ARE PRETTY QUIET SO FAR THIS MORNING. SKIES
ARE MOSTLY CLEAR WITH FAIRLY LIGHT WINDS OUTSIDE THE WIND PRONE
AREAS. TEMPERATURES QUITE WARM WITH MAINLY MID TO UPPER 30S BEING
REPORTED. WINDS SO FAR AT OUR WIND PRONE AREAS ARE GUSTING IN THE
UPPER 30S TO LOW 40S AND ARE EXPECTED TO CONTINUE INCREASING AS
THE MORNING PROGRESSES. TO THE NORTHWEST OVER WASHINGTON
STATE...OUR NEXT WINTER STORM COMING ONSHORE OVER SOUTHERN BRITISH
COLUMBIA AND WASHINGTON.
FOR TODAY...THE HIGH WIND EVENT IS STILL ON TRACK WITH LATEST
WRKHGT PRODUCT SHOWING CRAIG TO CASPER 850 AND 700MB HEIGHT
GRADIENTS INCREASING TO NEAR 60MTRS BY 18Z TODAY. THESE GRADIENTS
EXPECTED TO CONTINUE INCREASING THIS AFTERNOON AND OVERNIGHT TO
NEARLY 84 MTRS AT 850MBS AND 81 MTRS AT 700MB BY 12Z MONDAY. THIS
IS GOING TO BE A PRETTY IMPRESSIVE HIGH WIND EVENT AS WE DO NOT
NORMALLY SEE THESE TYPES OF GRADIENTS WITH OUR NORMAL RUN OF THE
MILL HIGH WIND EVENTS. WENT AHEAD AND STARTED THE WIND PRONE
AREAS OF SOUTHEAST WYOMING IN WIND WARNING CRITERIA BY 18Z TODAY.
LATEST MOS GUIDANCE SHOWING RAWLINS AND LARAMIE INCREASING IN
WINDS TODAY THROUGH THE LATE AFTERNOON AND OVERNIGHT. WENT AHEAD
WITH A HIGH WIND WARNING FOR CARBON AND ALBANY COUNTIES BEGINNING
AT 7 PM THIS EVENING. KEPT CONVERSE AND LARAMIE COUNTIES IN THE
HIGH WIND WATCH FOR NOW. DAY SHIFT CAN TAKE ANOTHER LOOK TO
UPGRADE AND/OR EXPAND FURTHER EAST LATER TODAY. LOOKS LIKE WE ARE
GOING TO NEED SOMETHING FOR THE PANHANDLE AS 850MB WINDS INCREASE
TO 45 KNOTS MONDAY MORNING.
ONE LAST THING FOR TODAY IS THE SNOWY AND SIERRA MADRE RANGES.
QPF OUTPUT PRETTY MEAGER FOR THESE TWO ZONES TODAY. STILL THINK
THE OUTPUT IS UNDERDONE...BUT WILL DEFER TO THE DAY SHIFT. DID GO
AHEAD AND ISSUE A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING
SNOW. IF LATER SHIFTS SEE QPF AMOUNTS INCREASING...WE MAY NEED TO
ISSUE A SHORT FUSED WINTER STORM WARNING OUT THAT WAY.
700MB WINDS FOR MONDAY VERY IMPRESSIVE WITH THE 12Z GFS
FORECASTING 70 TO 75KTS AT 06Z TONIGHT AND LASTING THROUGH 06Z
TOMORROW NIGHT AHEAD OF THE APPROACHING COLD FRONT. LOOKS LIKE THE
FRONT MOVES INTO CONVERSE COUNTY LATE MONDAY EVENING AND THROUGH
THE CHEYENNE AREA/SOUTHERN PANHANDLE BY 12Z TUESDAY. PROBABLY WILL
NOT SEE MUCH IN THE WAY OF SNOW EAST OF THE LARAMIE RANGE UNTIL
THE WINDS SWITCH TO THE NORTHEAST BEHIND THE FRONT LATER TUESDAY
MORNING. VERY COLD 700MB TEMPERATURES BEHIND THE FRONT AS
WELL...DROPPING FROM 0C MONDAY AFTERNOON...TO -18C TUESDAY
AFTERNOON.
GOT A CALL FROM AN AREA RANCHER OVERNIGHT. THEY ARE IN THE MIDDLE
OF CALVING SEASON. PASSED ON THAT THEY PROBABLY WANT TO GET THEIR
CATTLE SHELTERED BEFORE TUESDAY AFTERNOON AS TEMPERATURES ARE
GOING TO BE SHARPLY DROPPING AND WIND CHILLS FALL WELL BELOW ZERO
TUESDAY NIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 337 AM MST SUN DEC 1 2013
00Z MODELS ARE IN FAIR AGREEMENT WITH THE LARGER SCALE SYNOPTIC
PATTERN AS THE DEEP UPPER TROUGH DIGS INTO THE WESTERN CONUS TUESDAY
NIGHT AND WEDNESDAY. A POTENT SHORTWAVE AT THE BOTTOM OF THE
TROUGH LOOKS TO MOVE ACROSS UT/NV AND INTO CO ON WEDNESDAY WITH SFC
CYCLOGENESIS OCCURRING OUT AHEAD OF THE WAVE. THE LOW CENTER IS
PROGGED TO BE OVER SOUTHWESTERN CO BY 18Z WEDNESDAY WITH AN INVERTED
TROUGH DEVELOPING ALONG THE ROCKIES. THIS COULD DO TWO THINGS. FIRST
IT COULD INCREASE NORTHEASTERLY WINDS AND THEREFORE UPSLOPE FORCING
ALONG THE LARAMIE RANGE DEPENDING WHERE EXACTLY THE INVERTED TROUGH
SETS UP. SECOND...IT COULD HOLD BACK THE SURGE OF ARCTIC AIR OVER
THE MOUNTAINS UNTIL LATER IN THE PERIOD. WITH SOME UNCERTAINTY YET
IN THIS SCENARIO...DID NOT MAKE ANY DRASTIC CHANGES TO THE ONGOING
FORECAST FOR POPS...WINDS AND TEMPS THROUGH WEDNESDAY. KEPT HIGHER
POPS OVER THE HIGH COUNTRY WHERE THE STRONGER PVA AND POTENTIAL
NORTHEASTERLY UPSLOPE COULD BE MAXIMIZED. PLENTY OF MOISTURE LOOKS
TO MOVE UP WITH THE SHORTWAVE SO IF THIS SCENARIO IS REALIZED...SNOW
WILL BE WIDESPREAD OVER THIS AREA AND COULD SEE MODERATE RATES AT
TIMES. ONE CAVEAT IS THAT VERY COLD TEMPS COULD LIMIT ACCUMULATION
OVERALL DUE TO A FINER SNOW TYPE. FURTHER EAST...BROADSCALE LIFT
AHEAD OF THE UPPER WAVE WILL BRING A GOOD CHANCE FOR SNOW THROUGH
WEDNESDAY AND WEDNESDAY NIGHT...ESPECIALLY FOR THE SOUTHERN HALF
OF THE CWA.
SNOW WILL STEADILY DIMINISH FROM NORTH TO SOUTH THURSDAY BUT
MODELS SHOW SOME LINGERING LIGHT QPF THROUGH THURSDAY. THIS
SUGGESTS LIGHT SNOW/FLURRIES WILL PERSIST AT TIMES AS THE ARCTIC
HIGH MAKES A STRONGER PUSH TOWARD THE FORECAST AREA AND INDUCES
WEAK UPSLOPE FLOW IN A VERY COLD AIRMASS. SKIES SHOULD BEGIN TO
CLEAR THURSDAY NIGHT WHICH WILL ALLOW TEMPS TO PLUMMET WELL BELOW
ZERO ACROSS THE MAJORITY OF THE FORECAST AREA. HOWEVER...ANY
LINGERING CLOUD COVER WILL IMPACT JUST HOW LOW TEMPS WILL FALL
OVERNIGHT. FRIDAY WILL REMAIN VERY COLD UNDER 700 MB TEMPS OF
MINUS 20 TO MINUS 26...AND LIGHT SNOW/FLURRIES COULD VERY WELL
CONTINUE IN THIS FRIGID ENVIRONMENT. ANOTHER SHORTWAVE WILL
APPROACH FROM THE WEST ON SATURDAY AND WILL REINFORCE THE COLD
AIRMASS AND POTENTIAL FOR LIGHT SNOW ACROSS THE CWA. SO AS IT
STANDS...LOOKS LIKE THIS WILL BE A LONG DURATION COLD
SPELL...WHICH WILL HAVE A HIGH IMPACT ON LIVESTOCK AND ANY PERSONS
PLANNING OUTDOOR RECREATION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY MORNING)
ISSUED AT 1027 PM MST SAT NOV 30 2013
SCATTERED TO BROKEN MID LEVEL CLOUDS WILL PREVAIL TONIGHT...WITH
MVFR TO IFR CIGS DEVELOPING OVER WESTERN AND SOUTHERN CARBON
COUNTY BY DAYBREAK SUNDAY. NAM MOS AND HRRR HAVE BEEN CONSISTENT
WITH AT LEAST IFR CIGS INVOF KRWL AND KSAA AIRFIELDS. KEPT
PREVAILING BKN015 THROUGH SUNDAY AFTERNOON AT KRWL. SNOW SHOWERS
WILL DEVELOP AND OBSCURE THE SNOWY AND SIERRA MTNS SUNDAY. IT WILL
BE BREEZY TO WINDY SUNDAY WITH WESTERLY WINDS POSSIBLY GUSTING AS
HIGH AS 50 KT FOR THE WIND CORRIDORS OF SOUTHEAST WY. GUSTS TO 35 KT
ARE EXPECTED ELSEWHERE...EXCEPT 25 KT IN WESTERN NEBRASKA.
&&
.FIRE WEATHER...
ISSUED AT 337 AM MST SUN DEC 1 2013
WIDESPREAD HIGH WIND EVENT STILL ON TRACK TO BEGIN IMPACTING THE
AREA STARTING LATE THIS MORNING AND PERSISTING THROUGH TUESDAY
MORNING. WINDS INITIALLY INCREASING IN OUR SOUTHEAST WYOMING WIND
PRONE AREAS...BUT THEN SPREADING OUT TO OTHER AREAS LATER THIS
AFTERNOON AND TONIGHT. THIS IS ALL DUE TO A PACIFIC LOW PRESSURE
SYSTEM TRACKING INTO MONTANA TODAY. THIS LOW WILL DRAGS A COLD
FRONT THROUGH THE AREA MONDAY AFTERNOON WITH WINDS SHIFTING FROM
WEST TO NORTHEAST BEHIND THE FRONT. WIDESPREAD ACCUMULATING SNOW
AND BITTERLY COLD TEMPERATURES BEHIND THE FRONT FOR MOST AREAS
TUESDAY AND ON THROUGH THE WEEK. SNOW ENDING FOR MOST LOCATIONS BY
THURSDAY...BUT EXTREME COLD TEMPERATURES PERSISTING INTO THE
WEEKEND.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 11 AM MST
MONDAY FOR WYZ112-114.
HIGH WIND WARNING FROM 11 AM THIS MORNING TO 5 AM MST TUESDAY
FOR WYZ106-107-110-116-117.
HIGH WIND WATCH FROM THIS EVENING THROUGH LATE MONDAY NIGHT FOR
WYZ101-118.
HIGH WIND WARNING FROM 7 PM THIS EVENING TO 5 AM MST TUESDAY FOR
WYZ104-105-109-115.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...RJM
AVIATION...JAMSKI
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1039 PM MST SAT NOV 30 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 350 PM MST SAT NOV 30 2013
MAIN CONCERN THROUGH THE SHORT TERM WILL BE WIND SPEEDS...
ESPECIALLY THROUGH THE HIGH WIND CORRIDORS. CONVERSE COUNTY HAS
BEEN ADDED TO THE HIGH WIND WATCH...OTHERWISE NO CHANGES TO THE
HAZARD GRIDS. TIMING OF WHEN WINDS WILL ACTUALLY START HITTING
HIGH WIND CRITERIA IS SOMEWHAT IN QUESTION. ARLINGTON AND BORDEAUX
COULD GET CLOSE LATE TONIGHT THROUGH ABOUT SUNRISE BUT IT LOOKS
LIKE THE MAIN THREAT FOR STRONGER WINDS WILL HOLD OFF UNTIL MONDAY
AFTERNOON WHEN A STRONG UPPER LEVEL JET PUSHES INTO SOUTHEAST
WYOMING. GFS IS FASTER WITH THE ARRIVAL OF THE UPPER JET AND THUS
FASTER RAMPING UP THE STRONG SURFACE WINDS AND THE GFS IS
INDICATING STRONGER WINDS OVERALL. THE NAM IS A GOOD 6 HOURS
SLOWER WITH THE ARRIVAL OF THE STRONGEST WINDS WHICH COULD BE
DELAYED UNTIL AROUND 00Z MONDAY FOR WIND PRONE AREAS. REGARDLESS
IT IS GOING TO BE VERY WINDY SUNDAY NIGHT AND CONTINUE INTO MONDAY
WITH STRONG WINDS SPREADING EAST INTO THE PLAINS.
WINTER STORM WATCH REMAINS IN EFFECT FOR THE SNOWY AND SIERRA
MADRE RANGES. 18Z NAM HAS BACKED OFF THE QPF AMOUNTS OVER THE
MOUNTAINS AND THE GFS IS BARELY GENERATING ANY QPF...OF COURSE THE
MODELS TEND TO UNDER ESTIMATE QPF IN THIS TYPE OF FLOW REGIME.
KEPT THE SNOW AMOUNTS AT THE HIGH END OF THE POTENTIAL RANGE FOR
NOW...BUT IF THE NAM CONTINUE TO TREND DRIER...MAY NEED TO LOWER
AMOUNTS. THE MAIN CONCERN IS THAT EVEN WITH LESSER SNOW AMOUNTS
SUSTAINED WINDS WILL LIKELY HIT 50 MPH WITH HIGHER GUSTS PRODUCING
BLOWING SNOW AND SIGNIFICANT REDUCTION IN VISIBILITIES. TOUGH CALL
BETWEEN A HIGH WIND WARNING...WINTER STORM WARNING OR A WINTER
WEATHER ADVISORY FOR THE MOUNTAINS...OF COURSE THE MAIN CHANCE FOR
HIGH SNOW ACCUMULATIONS OVER THE MOUNTAINS WILL NOT OCCUR UNTIL
TUESDAY AND WEDNESDAY.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 305 PM MST SAT NOV 30 2013
ARCTIC FRONT WILL SWEEP ACROSS THE CWA TUESDAY WITH GFS THE
FASTEST SOLUTION...SOMEWHAT AN OUTLIER WITH MOST OTHER MODELS A
BIT SLOWER. THIS WILL IMPACT MAX TEMPERATURES FOR TUESDAY AS
TEMPERATURES WILL PLUNGE ONCE THE FRONT PASSES. MUCH COLDER
TEMPERATURES EXPECTED FOR THE REST OF THE WEEK UNDER BROAD
CYCLONIC UPPER FLOW. VERY COLD CONDITIONS FOR THURSDAY AND FRIDAY
WHEN HIGHS MAY STRUGGLE TO REACH THE TEENS AS VERY LOW THICKNESSES
PASS ACROSS THE REGION.
PRECIPITATION-WISE...SNOW SHOULD BE ONGOING AT TIMES OVER THE
HIGHER MTNS AND WEST DURING THE DAY TUESDAY THEN POST-FRONTAL
LIGHT SNOWS SHOULD INCREASE OVER THE EASTERN PLAINS TUESDAY
AFTERNOON AND NIGHT AS UPSLOPE FLOW DEEPENS AND MOISTURE
INCREASES. SNOW SHOULD CONTINUE OVER MANY AREAS WEDS THEN TAPER
OFF FROM NORTH TO SOUTH WEDS EVENING AS SFC HIGH BUILDS IN AND
BETTER MOISTURE AND UPSLOPE FLOW SHIFTS SOUTH INTO COLORADO. COULD
BE SOME PRETTY GOOD SNOWFALL AMOUNTS MAINLY OVER AND NEAR THE MTNS
BUT VERY COLD AIRMASS SHOULD LIMIT ACCUMULATIONS SOME. MAINLY DRY
CONDITIONS THEN EXPECTED BY LATE THURSDAY THROUGH SATURDAY OUTSIDE
OF THE HIGHER MTNS WHERE SOME SNOW SHOWERS SHOULD RETURN BY THE
WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1027 PM MST SAT NOV 30 2013
SCATTERED TO BROKEN MID LEVEL CLOUDS WILL PREVAIL TONIGHT...WITH
MVFR TO IFR CIGS DEVELOPING OVER WESTERN AND SOUTHERN CARBON
COUNTY BY DAYBREAK SUNDAY. NAM MOS AND HRRR HAVE BEEN CONSISTENT
WITH AT LEAST IFR CIGS INVOF KRWL AND KSAA AIRFIELDS. KEPT
PREVAILING BKN015 THROUGH SUNDAY AFTERNOON AT KRWL. SNOW SHOWERS
WILL DEVELOP AND OBSCURE THE SNOWY AND SIERRA MTNS SUNDAY. IT WILL
BE BREEZY TO WINDY SUNDAY WITH WESTERLY WINDS POSSIBLY GUSTING AS
HIGH AS 50 KT FOR THE WIND CORRIDORS OF SOUTHEAST WY. GUSTS TO 35 KT
ARE EXPECTED ELSEWHERE...EXCEPT 25 KT IN WESTERN NEBRASKA.
&&
.FIRE WEATHER...
ISSUED AT 325 AM MST SAT NOV 30 2013
WINDS TO REMAIN BREEZY TODAY AND TONIGHT WITH INCREASING WINDS
THROUGH THE DAY SUNDAY INTO MONDAY. THEY COULD BECOME QUITE STRONG
SUNDAY AFTERNOON THROUGH MONDAY AFTERNOON FOR AREAS ALONG AND WEST
OF THE LARAMIE RANGE AND IMMEDIATELY TO THE EAST HERE NEAR
CHEYENNE AND UP BY WHEATLAND. FORTUNATELY...WE ARE LOOKING AT
AFTERNOON HUMIDITIES TO REMAIN IN THE 20S AND LOW 30S THROUGH
MONDAY WITH FAIR TO EXCELLENT OVERNIGHT RECOVERIES. SNOW WILL
BECOME WIDESPREAD NEXT WEEK FROM TUESDAY THROUGH THURSDAY. MOST
LOCATIONS WILL SEE ACCUMULATING SNOWS AS A LOW PRESSURE SYSTEM
TRACKS THROUGH THE AREA.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY AFTERNOON
FOR WYZ112-114.
HIGH WIND WATCH FROM SUNDAY MORNING THROUGH MONDAY AFTERNOON
FOR WYZ106-110-116-117.
HIGH WIND WATCH FROM SUNDAY EVENING THROUGH MONDAY AFTERNOON
FOR WYZ101-104-105-107-109-115-118.
NE...NONE.
&&
$$
SHORT TERM...LIEBL
LONG TERM...RE
AVIATION...JAMSKI
FIRE WEATHER...LIEBL
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
334 AM CST TUE DEC 3 2013
.DISCUSSION...
330 AM CST
FORECAST FOCUS REMAINS LARGELY ON THE NEAR TERM THIS MORNING...
NAMELY PRECIPITATION AND TEMPERATURE TRENDS TODAY THROUGH WEDNESDAY
AS DEEP LOW PRESSURE SYSTEM DEVELOPS IN RESPONSE TO AMPLIFICATION OF
UPPER TROUGH ACROSS THE WESTERN/CENTRAL CONUS. DAYS 3-7 CONTINUE TO
FEATURE MUCH COLDER THAN AVERAGE TEMPERATURES...WITH THE POTENTIAL
FOR A COUPLE OF LIGHT SNOW EVENTS MAINLY ACROSS THE FAR SOUTHEAST
LATE THURSDAY-FRIDAY...AND FOR MOST OF THE AREA SUNDAY/SUNDAY NIGHT.
00Z RAOB ANALYSIS INDICATES FAIRLY ZONAL FLOW PATTERN ACROSS THE
CENTRAL CONUS...WITH A DEEP SHORT WAVE TROUGH DIGGING SOUTHEAST
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SEVERAL RELATIVELY MINOR
AMPLITUDE SHORT WAVES WERE NOTED DOWNSTREAM ACROSS THE MIDWEST...
EMANATING FROM STRONG JET STREAK DEVELOPS AROUND THE SOUTHERN
PERIPHERY OF THE DIGGING TROUGH. ONE SUCH WAVE WAS NOTED IN WATER
VAPOR IMAGERY OVER THE UPPER MISSISSIPPI VALLEY EARLY THIS
MORNING...WHICH WAS RESPONSIBLE FOR AN AREA OF WARM ADVECTION
PRECIPITATION THAT MOVED ACROSS THE FORECAST AREA OVERNIGHT AND WAS
NOW EAST OF THE REGION. A COUPLE OF MORE SUBTLE MID-LEVEL WAVES WERE
NOTED IN THE SATELLITE IMAGERY...ONE APPROACHING QUICKLY FROM
EASTERN IA...AND THE OTHER UPSTREAM ACROSS WESTERN NEBRASKA. THESE
FEATURES WILL RIPPLE QUICKLY EAST ACROSS THE AREA TODAY...MAINLY
WORKING TO MAINTAIN SOUTHERLY FLOW AND CONTINUED WARM ADVECTION INTO
THE MIDWEST. WHILE SOME SPOTTY LIGHT RAIN IS POSSIBLE WITH ANY OF
THESE SUBTLE FEATURES...UPSTREAM SOUNDINGS FROM OMA/TOP/SGF INDICATE
FAIRLY DRY MID-LEVELS. FORECAST SOUNDINGS MAINTAIN THIS DRY LAYER
ROUGHLY BETWEEN 850-650 MB WHICH SUGGESTS MAINLY SCATTERED LIGHT
RAIN OR SOME DRIZZLE WITH ONLY LIGHT QPF AMOUNTS TODAY-TONIGHT AS
FORCING WITH THESE WAVES ACT ON MOIST LOW LEVELS OR BRIEF POCKETS OF
ENHANCED MID-LEVEL MOISTURE.
WITH ONGOING WARM ADVECTION...SURFACE TEMPERATURES AND DEW POINTS
WILL CONTINUE TO SLOWLY RISE AS A WARM FRONT CURRENTLY LIFTING INTO
CENTRAL ILLINOIS MOVES NORTH. WHILE THE BOUNDARY REMAINS A BIT
DIFFUSE EARLY THIS MORNING...THE FRONT SHOULD SHARPEN AND BEGIN TO
MOVE FASTER LATER TODAY AND TONIGHT AS SURFACE LOW PRESSURE DEEPENS
TO OUR WEST ACROSS THE CENTRAL PLAINS IN RESPONSE TO HEIGHT FALLS
WITH DEEPENING WESTERN TROUGH. MODELS ARE IN FAIRLY GOOD AGREEMENT
THAT THE SURFACE WARM FRONT SHOULD LIFT INTO NORTHERN IL BY LATE
AFTERNOON...WITH THE SOUTHERN AND CENTRAL PARTS OF THE CWA GETTING
INTO THE WARM SECTOR. TEMPS SHOULD REACH THE LOW-MID 50S ALONG AND
SOUTH OF I-80 THIS AFTERNOON...WITH 40S TO THE NORTH. IT WILL REMAIN
VERY MILD TONIGHT AS THE WARM FRONT REACHES THE IL/WI BORDER...WITH
OVERNIGHT LOWS HOLDING IN THE 40S ACROSS THE CWA.
GUIDANCE REMAINS IN TWO SEPARATE CAMPS WITH THE HANDLING OF THE MAIN
SURFACE LOW AND COLD FRONT ON WEDNESDAY...WITH THE DOMESTIC MODELS
REMAINING FASTER AND INITIALLY DEEPER BEYOND 30 HOURS THAN THE UK/EC
AND CANADIAN COUNTERPARTS. THE 00Z RUNS OF THE GFS AND TO A GREATER
EXTENT THE WRF HAVE SLOWED HOWEVER...WHICH LENDS SUPPORT TO OUR
FAVORING THE SLOWER SOLUTION OF THE UKMET/ECMWF AND GEM. THUS
CONTINUE TO FAVOR THE SCENARIO OF THE SURFACE LOW LIFTING ACROSS
EASTERN IOWA INTO WI WEDNESDAY AFTERNOON...AND THE TRAILING COLD
FRONT MOVING ACROSS THE WFO LOT FORECAST AREA FAIRLY LATE IN THE
AFTERNOON AND EVENING HOURS. THIS SUPPORTS TEMPS IN THE 50S...AND
EVEN A COUPLE OF 60S FAR SOUTH...WEDNESDAY WITH THE CWA STILL IN THE
WARM SECTOR AHEAD OF THE FRONT. MID-LEVEL MOISTURE CONTINUES TO BE
LIMITED...AND ALTHOUGH LIGHT RAIN/SHOWER CHANCES DO INCREASE WITH
THE APPROACH OF THE LOW/COLD FRONT THE BEST COVERAGE AND RAINFALL
AMOUNTS EXPECTED NORTH OF THE AREA ACROSS WI AND THE NORTHERN LAKES.
THE COLD FRONT PUSHES ACROSS THE AREA WEDNESDAY EVENING...SHUTTING
OFF PRECIP AS MID/UPPER LEVELS DRY OUT. THANKS TO WEST-SOUTHWEST
FLOW ALOFT THE FIRST PUSH OF COLDER AIR IS RELATIVELY WEAK...AS THE
FRONT AND LOW LEVEL BAROCLINIC ZONE SLOW UP FROM THE OHIO VALLEY TO
THE EASTERN LAKES INTO THURSDAY. A COUPLE OF DISTURBANCES RIPPLE
NORTHEAST ALONG THIS BAROCLINIC ZONE LATE THURSDAY INTO FRIDAY...
WITH THE POTENTIAL FOR SOME LIGHT SNOW FROM CENTRAL IL INTO NORTHERN
INDIANA AND MAINLY CLIPPING THE FAR SOUTHEAST PART OF THE CWA. A
SECOND PUSH OF COLDER AIR THEN SPREADS IN THURSDAY NIGHT-FRIDAY AS
THE UPPER LOW PASSES TO THE NORTH AND HEADS INTO EASTERN CANADA.
THIS ALLOWS 850 MB AIR OF -10 TO -15 C ACROSS THE AREA AND TEMPS A
GOOD 8-10F COLDER FRIDAY THAN ON THURSDAY. SOME DIFFERENCES REMAIN
WITH MODEL DETAILS AT THIS TIME...BUT CONTINUE TO FAVOR THE SIMILAR
GEM/ECMWF WHICH SUPPORTS HIGHS ONLY NEAR/AROUND 20 FRIDAY AND
SATURDAY AS ARCTIC HIGH PRESSURE BUILDS ACROSS THE MIDWEST. LOOKS
LIKE AT LEAST SOME SLIGHT MODERATION SUNDAY-MONDAY AS UPPER TROUGH
AMPLIFIES ACROSS THE WESTERN CONUS/NOAM...WITH AN AREA OF LOW
PRESSURE LIFTING ACROSS THE AREA SUNDAY WITH THE POTENTIAL FOR SOME
LIGHT SNOW.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* IFR CIGS EXPECTED TO PERSIST THROUGH THE OVERNIGHT
HOURS...POSSIBLY BOUNCE UP TO MVFR TUESDAY.
* PINNING DOWN BEST CHANCES FOR PRECIPITATION.
* VSBY BETWEEN 1SM-4SM OVERNIGHT
BMD
//DISCUSSION...UPDATED 06Z...
WARM FRONT IS DRAPED ACROSS IOWA INTO CENTRAL ILLINOIS LATE THIS
EVENING WITH AN AREA OF SHOWERS PUSHING EAST AWAY FROM THE TERMINALS
WITH LOWERING CIGS AND VSBYS SETTING IN BEHIND. EXPECT LITTLE CHANCE
IN CONDITIONS OVERNIGHT...THOUGH VSBY MAY BE VARIABLE AT TIMES
BETWEEN 1SM AND 4 SM. THE FRONT WILL SLOWLY LIFT NORTH THROUGH THE DAY
TUESDAY WITH DRIER MID LEVEL AIR OVERSPREADING THE LOW LEVEL
MOISTURE/IFR CIGS. THIS DRY MID LEVEL AIR SHOULD INHIBIT PRECIP FROM
DEVELOPING THROUGH MOST OF THE DAY TOMORROW. CIGS MAY REBOUND
SLIGHTLY DURING THE DAY...INTO LOWER MVFR CATEGORY BETWEEN
010-015...ESPECIALLY LATE MORNING OR EARLY AFTERNOON WHEN THE FRONT
LIFTS ACROSS THE TERMINALS AND WINDS TURN SOUTHERLY. AS THE SURFACE
LOW BEGINS TO DEEPEN OVER THE PLAINS TUESDAY EVENING...ASCENT WILL
INCREASE ACROSS THE AREA AND DESPITE THE STILL MODEST DEPTH OF
MOISTURE...FEEL THIS WILL BE THE BEST CHANCE FOR LIGHT RAIN OR
DRIZZLE TO DEVELOP OVER THE AREA. SOME GUIDANCE SUGGESTS THAT IFR
CIGS WILL DEVELOP AGAIN TOMORROW NIGHT.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM CONFIDENCE ON WIND DIRECTION/SPEED.
* MEDIUM-HIGH CONFIDENCE IN IFR CONDITIONS THROUGH OVERNIGHT HOURS
...LOW-MEDIUM CONFIDENCE IN REBOUNDING SLIGHTLY TO LOW END MVFR
TUESDAY AFTERNOON. LOW CONFIDENCE IN CIG TRENDS TUESDAY NIGHT.
* MEDIUM CONFIDENCE IN VSBY TRENDS OVERNIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...MVFR CIGS POSSIBLE. CHC OF RAIN.
THURSDAY...VFR. POSSIBLE PERIOD OF LIGHT SNOW/FLURRIES.
FRIDAY THROUGH SUNDAY...VFR.
BEACHLER
&&
.MARINE...
239 AM CST
STILL SIGNIFICANT DIFFERENCES IN THE MODELS WITH RESPECT TO LOW
PRESSURE THAT IS EXPECTED TO IMPACT THE LAKES MIDWEEK. GUIDANCE HAS
TRENDED TOWARDS A SLOWER FRONTAL TIMING AND MORE NORTHERLY LOW TRACK
THOUGH...A TYPICAL TREND WHEN THE UPPER AIR PATTERN IS AMPLIFIED.
WITH THAT IN MIND...HAVE BASED FORECAST TIMING ON A BLEND OF THE GEM
AND THE ECWMF WHICH HAVE BEEN FAIRLY CONSISTENT WITH SLOWER TIMING
AND WHICH THE FASTER NCEP GUIDANCE SEEMS TO BE TRENDING TOWARDS. A
DEEPENING AREA OF LOW PRESSURE IS EXPECTED TO LIFT FROM THE CENTRAL
PLAINS TODAY AND TOMORROW...ACROSS LAKE SUPERIOR OR WEDNESDAY NIGHT.
MODERATE SOUTHEAST TO EAST WINDS ARE EXPECTED AHEAD OF THE
LOW...THOUGH STABLE CONDITIONS WILL HELP KEEP THE HIGHER END GUSTS
FROM REACHING THE LAKE SURFACE. BEHIND THE FRONT...STRONG AND COLD
HIGH PRESSURE WILL OVERSPREAD THE PLAINS WITH A TIGHT GRADIENT ONLY
VERY GRADUALLY SUBSIDING THROUGH THE REST OF THE WEEK. THERE MAY BE
A SHORT PERIOD OF WESTERLY GALES IMMEDIATELY BEHIND THE FRONT
WEDNESDAY NIGHT INTO THURSDAY...WITH 30KTS REST OF THURSDAY INTO
FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 3 PM TUESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
[top]
Area Forecast Discussion
National Weather Service Lincoln IL
315 AM CST Tue Dec 3 2013
.DISCUSSION...
ISSUED 315 AM CST Tue Dec 3 2013
Main forecast concern continues to be potential for accumulating
snow and ice across parts of central Illinois Thursday into Friday.
SHORT TERM...Today through Thursday
Widespread fog blankets central Illinois early this morning,
thanks to light southerly winds and ample low-level moisture
flowing northward behind an advancing warm front. 08z/2am
visibilities are generally in the 2 to 4 mile range, but a few
pockets of locally dense fog are beginning to develop across
west-central and southwest Illinois. HRRR suggests visibilities may
continue to drop across this area over the next few hours. As a
result, will be issuing a Dense Fog Advisory for all locations
along and west of I-55 through 10AM. This may need to be expanded
eastward to include the remainder of the KILX CWA if visibility
trends continue. Fog will be slow to dissipate, but should clear
most of the area by around midday. Due to the fog and clouds
expected today, have trimmed previous high temperature forecast by
a few degrees, with readings ranging from the middle 50s far north
to around 60 degrees far south/southwest.
00z Dec 3 models have come into much better agreement concerning
approaching cold front on Wednesday. While the GFS/NAM remain the
fastest models, both have slowed FROPA considerably and are now
closer to the slower/more consistent ECMWF/GEM. With a clear slowing
trend noted, confidence is growing that front will remain west of
central Illinois until late Wednesday afternoon. As a result, have
boosted temperatures, with highs ranging from the lower 50s west
of the Illinois River to the middle 60s south of I-70. Rain
chances with the front still appear very low, as deepest moisture
remains further south. Will continue with just low chance POPs
during the day, with dry weather returning for all but the far SE
CWA Wednesday night into Thursday morning. Much colder air will
spill into the region behind the cold front, resulting in a 20 to
25 degree temperature drop on Thursday. Highs will range from
around 30 in the Illinois River Valley to around 40 south of I-70.
Wave of low pressure is expected to develop and track along the
departing cold front, spreading wintry precipitation into parts
of central and southeast Illinois late Thursday afternoon and
evening. Airmass will be cold enough to support snow along and
northwest of a Taylorville to Danville line, but things get a
little trickier further south. Both the NAM and GFS show a max
temp in the elevated warm layer of 3C, suggesting partial melting
of ice crystals and mixed phase precip reaching the ground. The
exact type of precip will depend on surface temps. Based on
expected afternoon highs, a mixture of snow and sleet will be
likely along the I-70 corridor, with mainly rain along and south
of highway 50 Thursday afternoon. As deeper colder air arrives,
the precip will change over to mainly snow Thursday night. The
exception will be along and south of highway 50, where warm wedge
aloft will remain strong enough to support sleet and perhaps some
freezing rain. Precip may tend to diminish/come to an end
overnight as initial wave passes to the northeast.
LONG TERM...Friday through Monday
A second wave will track along the slow-moving front on Friday:
however, its main precipitation shield is expected to be a bit
further southeast over the Ohio River Valley. Light snow or
flurries may occur as far northwest as I-55 on Friday, with the
steadier snows focused further south along/south of I-70. By the
time the precip comes to an end Friday afternoon, snowfall of
around 1 inch will be possible along a Jacksonville to Danville
line, with as much as 2 to 3 inches further south along the I-70
corridor.
Once precip shuts off, dry and very cold weather will be on tap
through Saturday with high temps only in the 20s and lows dropping
into the single digits and teens. After that, models are trying to
bring another upper-level disturbance across the region late in
the weekend, possibly bringing a period of light snow
Sunday/Sunday night. Given very dry airmass initially in place, am
skeptical that much snow will fall. Have therefore kept POPs in
the low chance category with only minimal accumulations.
Barnes
&&
.AVIATION...
ISSUED 1140 PM CST Mon Dec 2 2013
Lower clouds continue to move northeast out of the area, but are
affecting BMI for another hour or two, and may affect CMI for an
hour. Reminder of the sites have only a large mid deck of clouds
around 12kft moving over them; which will affect BMI and CMI
shortly. Light fog remains an issue as well and will it will
remain foggy at all sites overnight and into the morning hours.
Vis could get lower in the morning hours so have kept a TEMPO
group at all sites for the early morning hours around sunrise. The
mid clouds around 10kft will continue into the afternoon at all
sites and into the evening hours. However, SPI and DEC appear to
become clear around sunset, while the other sites keep clouds over
them. Winds will be southeast to start and then become more
southerly during the day.
Auten
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY until 10 AM CST this morning FOR ILZ027>031-
036>038-040>043-047>053.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1149 PM CST MON DEC 2 2013
.SHORT TERM /TONIGHT/...
ISSUED AT 424 PM CST MON DEC 2 2013
SKIES ARE CLEARING RAPIDLY FROM WEST TO EAST THIS AFTERNOON...BUT
SOME HIGH CLOUDS ARE FILLING BACK IN FROM THE NORTHWEST PER
SATELLITE IMAGERY. AS EXPECTED A WARM FRONT HAS NOSED INTO OUR SOUTH
AND SOUTHWEST AND CONTINUES TO ADVANCE TOWARD CENTRAL
IOWA...BRINGING TEMPERATURES IN THE 50S WITH IT. A QUIET NIGHT IS IN
STORE AS WINDS REMAIN GENERALLY FROM THE SOUTHEAST BUT MID/HIGH
CLOUDS STEADILY THICKEN AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM.
THIS WILL RESULT IN TEMPERATURES STAYING RELATIVELY WARM IN THE MID
TO UPPER 30S IN MOST AREAS OVERNIGHT. FORECAST SOUNDINGS ALSO
INDICATE THAT BY SUNRISE TUESDAY THERE WILL BE QUITE A DEEP
SATURATED LAYER ASSOCIATED WITH THE MID/HIGH CLOUDS...HOWEVER A
POWERFUL NEAR SURFACE DRY LAYER WILL REMAIN IN PLACE. THIS SHOULD
RESULT IN A SCENARIO SIMILAR TO THIS MORNING WHEREBY ANY PRECIP THAT
FORMS LATE TONIGHT WILL FALL IN THE FORM OF VIRGA EVAPORATING BEFORE
IT HITS THE SURFACE...THEN DURING THE DAY TUESDAY PRECIP WILL BE
MORE LIKELY TO REACH THE GROUND AT TIMES. THUS HAVE REMOVED POPS
OVERNIGHT...ALTHOUGH SPRINKLE WORDING MAY NEED TO BE INTRODUCED
LATER FOR THE PRE DAWN HOURS.
.LONG TERM /TUESDAY THROUGH MONDAY/...
ISSUED AT 424 PM CST MON DEC 2 2013
MAJOR CHALLENGE IN NEAR TERM IS TRACK OF LOW AND LOCATION/TIMING OF
ASSOCIATED FROPA. THE RAP HAS BEEN INITIALIZING THE BEST ALL
MORNING. BY TUESDAY AFTERNOON...GFS A LITTLE FASTER THAN RAP...AND
NAM A LITTLE SLOWER AND FURTHER SOUTH. ECMWF SEEMS TO SOMEWHAT OF AN
OUTLIER ON TRACK OF LOW. IT SEEMS THE NAM HAS THE BEST HANDLE ON THE
SITUATION...SO PUSHING BACK TIME OF COLD FROPA AND HAVE SUBSEQUENTLY
INCREASED TEMPS OVER GUIDANCE AND PREVIOUS FORECAST.
ADDITIONALLY...THERE COULD BE SOME SUNSHINE IN SOUTHWESTERN IOWA
AS DRIER AIR BEING ADVECTED INTO LOWER LEVELS...WHICH COULD
ACTUALLY HELP TEMPS WARM UP INTO THE MID 60S. DECENT MOISTURE
CONVERGENCE AND FORCING ALONG COLD FRONT. HOWEVER...SOUNDING
PROFILES NOT VERY SATURATED IN DMX CWA SO PRECIP MAY STRUGGLE TO
REACH GROUND...THUS LOW QPF FORECAST. STRONG CAA AND TEMP GRADIENT
BEHIND FRONT...SO PRECIP TYPE WILL BE TOUGH TO PIN DOWN. THE
TRANSITION ZONE FROM RAIN TO SNOW WILL BE VERY NARROW. BETTER
FORCING TOWARDS MINNESOTA...SO HIGHER POPS TO THE NORTH.
FOR THURSDAY...GFS SOUNDINGS NOW KEEP THE PROFILE VERY SATURATED
DURING THE MORNING. A FEW FLURRIES MAY FALL DURING THE MORNING...BUT
NOT A LOT OF SUPPORT IN THE ATMOSPHERE FOR ANYTHING THAT WOULD
NOTABLY IMPACT THE PUBLIC. ALL MODELS HAVE SUBSIDENCE AND DRY
NORTHWESTERLY FLOW BEING ADVECTED DOWN TO CWA...ESPECIALLY THE
NAM...DURING THE AFTERNOON. THEREFORE...THINK CLOUDS SHOULD BEGIN
TO BREAK UP DURING THE DAY. DUE TO LACK OF FORCING HAVE REDUCED
POPS FOR THURSDAY PM.
THURSDAY/S TEMPERATURES SLIGHTLY TRICKY. AS MENTIONED ABOVE...CLOUDS
COVER LIKELY TO BE PRESENT DURING THE MORNING BUT WILL BREAK UP
DURING THE AFTERNOON. ADDITIONALLY...IT APPEARS WIND SPEEDS WILL
REMAIN NEAR THE 10 TO 15KT RANGE. CAA THROUGHOUT THE DAY AS H850
TEMPS WILL START THE DAY AROUND -10C AND END THE DAY NEAR -13C.
THEREFORE WENT SEVERAL DEGREES ABOVE GUIDANCE FOR THURSDAY
MORNING...AND WILL INCREASE DAYTIME TEMPERATURES A FEW DEGREES WITH
THE ANTICIPATED SUNSHINE. IN LOCATIONS WHERE SUN CANNOT MAKE IT
THROUGH...TEMPS WILL LIKELY HOLD STEADY OR DECREASE DURING THE DAY.
BY FRIDAY MORNING...PRESSURE GRADIENT STILL PRETTY TIGHT IN ADVANCE
OF APPROACHING HIGH SO WINDS WILL STAY AT LEAST AROUND 10 KTS.
THOUGH NOT A PURE RADIATIONAL COOLING NIGHT...WITH H850 TEMPS
APPROACHING -17C...APPARENT TEMPERATURE AT SURFACE WILL APPROACH
ZERO DEGREES...AND MAY EVEN BE BELOW ZERO IN SOME LOCATIONS. SUNNY
SKIES WILL PREVAIL FOR THE AFTERNOON...BUT HIGHS WILL STRUGGLE TO
MAKE IT OUT OF THE TEENS AS NO WAA EXPECTED.
FOR THE WEEKEND...GFS AND EURO CAME INTO SLIGHTLY BETTER AGREEMENT
WITH THEIR 12Z RUNS. HOWEVER...THERE IS STILL QUITE A BIT OF
DISAGREEMENT. BOTH MODELS DEVELOP A SIZABLE TROUGH THAT PUSHES OFF
THE ROCKIES. THE EURO HAS A MUCH MORE SOUTHERLY TRACK...PUTTING THE
REGION INTO SOUTHWESTERLY FLOW AND BRINGING MUCH GREATER CHANCE FOR
WINTRY PRECIP TO THE AREA. THE GFS ENSEMBLES KEEP THE LOW FURTHER
NORTH...KEEPING THE CWA IN WESTERLY TO NORTHWESTERLY FLOW...WHICH
WOULD KEEP COOL...DRY AIR ALOFT AND REDUCE PRECIPITATION CHANCES
FOR DMX.
&&
.AVIATION...03/06Z
ISSUED AT 1148 PM CST MON DEC 2 2013
PRIMARY CONCERN REMAINS VSBY/CIG TRENDS INTO TUE. 06Z SURFACE
ANALYSIS STILL SHOWS WARM FRONT BISECTING IA NW-SE WITH
DETERIORATING MVFR-LIFR CONDITIONS NOTED N AND E OF THE FRONT.
WITH LITTLE CHANGE ANTICIPATED OVERNIGHT...LINGERING LOW LEVEL
MOISTURE AND LIGHT SELY WINDS...EXPECT CONDITIONS TO DEGRADE
FURTHER DIURNALLY WITH AT LEAST MVFR VSBYS S AND W OF THE FRONT
AND LIFR CONDITIONS N AND E /KMCW/KALO/. CONDITIONS MAY IMPROVE
SOMEWHAT WITH INSOLATION TUE...BUT MVFR VSBYS/CIGS WILL LIKELY
LINGER AT LEAST INTO MIDDAY ALONG AND NORTH OF THE BOUNDARY WITH
LITTLE PATTERN CHANGE. LIGHT RAIN MAY ALSO CLIP FAR NRN IA /KMCW/
EARLY TUE EVENING AS WELL.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...LEE
LONG TERM...KOTENBERG
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 AM EST TUE DEC 3 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 447 AM EST TUE DEC 3 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RELATIVELY WEAK
ZONAL FLOW ALF OVER THE UPR GRT LKS TO THE N OF FASTER POLAR JET
OVER THE SRN 2/3 OF THE CONUS. THERE ARE 2 SHRTWVS OF NOTE EMBEDDED
IN THIS FLOW. THE FIRST IS MOVING E THRU MN AND CAUSING A BAND OF SN
EXTENDING FM NE MN SEWD OVER WRN LK SUP AND INTO CENTRAL WI AS OF
06Z UNDER AREA OF H85-5 QVECTOR CNVGC. THE AXIS OF HIER
REFLECTIVITIES IN WI APPEARS TO BE ORIENTED ALONG THE MOST
IMPRESSIVE ISENTROPIC ASCENT SHOWN ON THE 290K SFC /H7-75/...WHILE
THE MOST IMPRESSIVE RETURNS IN NE MN ALIGN WITH MOST VIGOROUS H85-5
QVECTOR CNVGC. THE 00Z INL/MPX RAOBS SHOW DEEP MSTR THRU THE DEPTH
OF THE TROP. ELY FEED OF DRIER LLVL AIR ASSOCIATED WITH AREA OF
MOCLR SKIES/HI PRES RDG AXIS STILL OVER FAR ERN UPR MI AND LOCATION
OF SHARPER H85 THERMAL PACKING/ISENTROPIC ASCENT TO THE S HAS SO FAR
LIMITED THE ENE EXTENT OF THE PCPN INTO UPR MI...BUT SN APPEARS
POISED TO SPREAD INTO THE WRN CWA PER LATEST SFC OBS/RADAR IMAGERY.
THE VSBY AT IWD FELL UNDER 2 MILES AT 07Z...AND THE VSBY AS CLOSE AS
ASHLAND IN NW WI IS DOWN TO 1/2 MILE. ENE FLOW DOWN WRN LK SUP MAY
BE ENHANCING THE SN INTO THIS AREA. IN THE AREA OVER WRN MN/MUCH OF
THE DAKOTAS UNDER DNVA/DEEP LYR QVECTOR DVGC BEHIND THE MN SHRTWV...
THERE IS LTL IF ANY PCPN FALLING EVEN THOUGH SKIES REMAIN CLDY WITH
QUITE A BIT OF MID LVL DRYING ABV LLVL MSTR SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. FARTHER TO THE W...THE 2ND MORE IMPRESSIVE
SHRTWV OF INTEREST IS MOVING EWD THRU THE NRN ROCKIES. 12HR H3 HGT
FALLS UP TO 200M AND H3 WIND SPEEDS UP TO 100M IN THE ACCOMPANYING
JET CORE ARE ASSOCIATED WITH THIS MORE IMPRESSIVE DISTURBANCE.
MAIN FCST CONCERNS IN THE SHORT TERM PERIOD ARE POPS/EXPECTED SN
ACCUMS THRU THIS MRNG ASSOCIATED WITH THE FIRST SHRTWV IN MN AND
NEED FOR ANY HEADLINES. FOCUS FOR TNGT TURNS TO POPS AND SN AMOUNTS
THAT WL ACCOMPANY THE APRCH OF THE 2ND STRONGER SHRTWV.
TODAY...AS MN SHRTWV TRACKS TO THE E INTO PERSISTENT SFC RDG AXIS
JUST TO THE E OF UPR MI AND AWAY FM TROF DEEPENING OVER THE W...
AREA OF H85-5 QVECTOR CNVGC IS PROGGED TO DIMINISH SGNFTLY BY 18Z
WITH MID LVL DRYING UNDER DVLPG H85-5 QVECTOR DVGC. EXPECT THE HIER
POPS THIS MRNG OVER THE W AND SCENTRAL UNDER THE SHARPER H85-5
QVECTOR CVNGC/SHARPER 295K ISENTROPIC ASCENT/AREA OF H85-7 FGEN.
GIVEN PRESENCE OF 2.5G/KG SPECIFIC HUMIDITY AT THIS LVL...EXPECT UP
TO 3 INCHES OF SN FOR THE 6-9 HR PERIOD OVER THE SW HALF OF THE CWA.
SINCE THE SN IS LIKELY TO FALL A FOR CLOSER TO 12Z HRS AT IWD...UP
TO 4 INCHES MAY ACCUMULATE THERE BEFORE THE PCPN DIMINISHES TOWARD
NOON. ALTHOUGH THE DGZ IS RATHER NARROW...MODELS SHOW FAIRLY
IMPRESSIVE OMEGA IN THIS LYR THAT MAY INCH SN/WATER RATIOS CLOSER
TO 15:1. CONSIDERING THE LO VSBYS REPORTED AT ASHLAND IN THE ABSENCE
OF LAKE ENHANCEMENT WITH THE LARGER SCALE E WIND...OPTED TO ISSUE A
WINTER WX ADVY FOR GOGEBIC COUNTY THRU MID MRNG. OTRW...UPSLOPE E
WIND OFF LK MI MAY CAUSE STEADIER SN TO LINGER LONGER OVER THE
SCENTRAL. SN WL LIKELY MOVE INTO THE E DURING THE AFTN BUT WL BE MUCH
LIGHTER AS THE DYNAMIC SUPPORT FADES AND HITS DRIER AIR.
TNGT...ALTHOUGH THE EARLY EVNG WL FEATURE DNVA/LARGER SCALE QVECTOR
DVGC LEFT IN THE WAKE OF THE DEPARTING/WEAKENING SHRTWV...FAVORED
CNDN MODEL SHOWS AXIS OF SHARPER H85-7 FGEN SUPPORTING BAND OF SN
NOW OVER SDAKOTA IMPACTING MAINLY THE SRN CWA FOR A COUPLE HRS IN
THE LATER EVNG. THE 00Z GFS/ECWMF SHOW A SIMILAR QPF...SO WENT FOR
HI END LIKELY POPS IN THIS AREA BY LATER IN THE EVNG. OVERALL MODEL
QPF UP TO 0.25 INCH WL SUPPORT A FEW INCHES OF SN IN THIS AREA. HIER
POPS/MORE SN MAY ARRIVE LATE OVER THE W AS THE DYNAMICS IN ADVANCE
OF THE SHRTWV MOVING THRU THE NRN ROCKIES PUSH TOWARD THE AREA. BUT
MODELS DISAGREE ON THE TIMING OF THE ARRIVAL OF THE DEEP LYR QVECTOR
CNVGC AS WELL AS INTENSITY OF THE SFC LO THAT MIGHT ACCOMPANY THE
LARGER SCALE FORCING. THE NAM/LOCAL WRF-ARW MODELS ARE THE MOST
AGGRESSIVE AT DEEPENING THE SFC LO AND BRINGING MORE PCPN FARTHER E.
BUT SINCE THE MAIN SHRTWV REMAINS SO FAR TO THE W THRU THE NGT...
SUSPECT THE SLOWER/WEAKER CNDN MODEL IS ON THE RIGHT TRACK. SO WENT
NO HIER THAN LIKELY POPS OVER THE FAR W FOR NOW. THE THERMAL FIELDS
FM THE CNDN MODEL INDICATE ENUF WARM AIR WL ARRIVE TO CAUSE THE SN
TO MIX WITH RA OVER THE FAR SCENTRAL.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EST TUE DEC 3 2013
CONTINUED CHALLENGING FORECAST IN STORE FOR WEDNESDAY THROUGH
WEDNESDAY NIGHT TIME FRAME AS A WINTER WEATHER SYSTEM TAKES AIM AT
THE UPPER GREAT LAKES. VERY COLD AIR IS EXPECTED TO BUILD IN ON THE
BACK SIDE OF THIS SYSTEM ALLOWING FOR VERY COLD TEMPERATURES FRIDAY
NIGHT THROUGH SATURDAY NIGHT.
WEDNESDAY INTO WEDNESDAY NIGHT...SITUATION LOOKS A BIT BETTER FROM A
FORECASTING STANDPOINT AS MODELS ARE COMING INTO BETTER AGREEMENT
WITH RESPECT TO THE HANDLING OF THE LOW PRESSURE SYSTEM POISED TO
AFFECT THE AREA THROUGH THIS TIME PERIOD. THE 00Z RUN OF THE NAM AND
GFS ARE FINALLY ALIGNING BETTER WITH THE MORE CONSISTENT
EC/GEM...ALTHOUGH THEY ARE A TOUCH FASTER AT SHIFTING THE LOW INTO
THE UPPER PENINSULA. AS OF 12Z/04 EACH OF THE MODELS ARE IN GOOD
AGREEMENT IN PLACING THE SURFACE LOW OVER SW WISCONSIN WITH VERY
SIMILAR INTENSITIES. THE UPPER LEVEL 500MB CLOSED LOW IS PROGGED TO
BE POSITIONED FARTHER NORTHWEST OVER NORTHWESTERN MN...INDICATING
THE POTENTIAL FOR ADDITIONAL INTENSIFICATION OF THE SURFACE LOW. AT
THAT TIME ISENTROPIC UPGLIDE IS EXPECTED TO CONTINUE AS SHOWN BY
ANALYZING MOISTURE AND MOISTURE TRANSPORT ON A 295K PRESSURE
ISOSURFACE. SOUNDINGS AROUND 12Z/04 INDICATE THAT MOST OF THE
PRECIPITATION EAST OF A MQT TO IMT LINE WILL LIKELY BE IN THE FORM
OF RAIN AS A FAIRLY DEEP WARM LAYER EXISTS IN THE BOUNDARY LAYER.
WEST OF THAT LINE ATMOSPHERIC PROFILES ARE SUCH THAT THE
PRECIPITATION SHOULD REMAIN IN THE FORM OF SNOW. ALSO AT THIS TIME
FORCING IN THE DGZ SEEMS FAIRLY LIMITED...HOWEVER...THIS WILL CHANGE
THROUGH THE DAY. THE LOW IS PROGGED TO BE OVER SOUTH CENTRAL WI BY
18Z/04. AS THIS LOW CONTINUES TO APPROACH DURING THIS TIME PERIOD
INCREASED MOISTURE AND FORCING IN THE DGZ IS EXPECTED TO INCREASE
ALLOWING FOR A STEADY INCREASE IN SNOWFALL INTENSITY DURING THE
AFTERNOON HOURS. BETWEEN 00Z/05 AND 06Z/05 THE LOW IS PROGGED TO
SHIFT NORTH AND EASTWARD INTO THE EAST CENTRAL PORTION OF THE UPPER
PENINSULA. INCREASED SNOWFALL RATES ARE EXPECTED TO CONTINUE DURING
THAT TIME PERIOD AS WELL...AS CONTINUED MOISTURE AND LIFT ARE
PROGGED TO BE COLLOCATED IN THE DGZ AS SHOWN BY ANALYZING 1000-500MB
RH AS WELL AS QCONV IN THE 700-500 DGZ LAYER AS IDENTIFIED USING
ATMOSPHERIC PROFILES OF THE EC/GEM. THE WESTERN HALF OF THE UPPER
PENINSULA LOOKS TO ALSO BE IN A FAVORED LOCATION FOR HEAVY SNOWFALL
AS THIS REGION IS IN THE FAVORED LEFT EXIT REGION OF AN UPPER LEVEL
JET. THE MAIN CAVEAT HERE IS THE NEW UNCERTAINTY WITH PRECIPITATION
TYPE WHICH WAS INTRODUCED BY THE 00Z EC/GEM/UKMET WHICH PULLS THE
SURFACE LOW MUCH FARTHER TO THE WEST...WHICH TAKES THE LOW VERY NEAR
WHERE THE PREVIOUS GFS MODELS WERE TAKING IT OVER THE PAST COUPLE OF
DAYS. THIS WOULD SHIFT THE RAIN SNOW LINE FARTHER WEST...POSSIBLY
REDUCING SNOWFALL TOTALS. HAVE DECIDED TO CONTINUE WITH AN UPDATED
SPS BASED ON COORDINATION WITH SURROUNDING OFFICES...AS CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO GO WITH A HEADLINE.
THURSDAY THROUGH SATURDAY...BETWEEN 12Z/05 AND 18Z/05 THE SURFACE
LOW IS PROGGED TO SHIFT NORTHEASTWARD TO JUST SOUTH OF JAMES
BAY...TAKEN THE BETTER SYNOPTIC FORCING OUT OF THE AREA. AT THE SAME
TIME A DEEP TROUGH DIGGING INTO THE NORTHERN PLAINS WILL BEGIN TO
INFLUENCE THE WEATHER IN THE UPPER PENINSULA. WINDS WILL BECOME
WESTERLY TO WEST NORTHWESTERLY IN THE RETURN FLOW ON THE BACK SIDE
OF THE LOW PRESSURE SYSTEM. THIS WILL ALLOW LAKE EFFECT SNOW DEVELOP
IN THE SNOWBELTS FAVORED WITH THE SAID WIND DIRECTION. 850MB
TEMPERATURES ARE EXPECTED TO DROP FROM NEAR -14C 12/05 TO AROUND
-22C 12Z/07. THESE TEMPERATURES ARE MORE THAN FAVORABLE FOR LES
GIVEN LAKE SURFACE TEMPERATURES AROUND 4C TO 5C...CREATING DELTA T
VALUES BETWEEN 18 AND 27 DEGREES THROUGH THIS TIME PERIOD.
WINDS...AGAIN...LOOK TO BE FAVORABLE WITH SURFACE TO 850MB WINDS
REMAINING OUT OF THE WEST...AND WELL WITHIN THE 30 DEGREE TOLERANCE
FOR LES. IT APPEARS AS IF THE TIME FRAME FOR HEAVIER LES WOULD OCCUR
THURSDAY EVENING INTO FRIDAY MORNING AS INVERSION HEIGHTS INCREASE
TO AROUND 8-9KFT AFTER ADJUSTING FOR LAKE SURFACE TEMPERATURES. THE
MOISTURE IS COLLOCATED WITH THE DGZ WHICH WOULD BE MORE FAVORABLE
FOR SNOWFLAKE PRODUCTION. FRIDAY AFTERNOON THROUGH SATURDAY
INVERSION HEIGHTS ARE EXPECTED TO BECOME MORE SHALLOW AS
TEMPERATURES ALSO BEGIN TO RAPIDLY DROP AS THE NEXT TROUGH AXIS
PRESSES INTO THE AREA. THESE COLDER TEMPERATURES WILL PRESS THE DGZ
DOWN TO THE VERY LOWEST LEVELS OF THE ATMOSPHERE. WHILE IT IS LIKELY
THAT SNOW WILL CONTINUE TO FALL THROUGH THE FRIDAY AFTERNOON INTO
SATURDAY TIME PERIOD...SNOW PRODUCTION WILL BE LIMITED AS THE
MOISTURE IS MAINLY OUTSIDE OF THE DGZ. TEMPERATURES THIS WEEKEND
WILL BE WELL BELOW NORMAL WITH TEMPERATURES DROPPING INTO THE TEENS
BELOW ZERO FRIDAY NIGHT INTO SATURDAY NIGHT...ESPECIALLY OVER THE
WEST HALF. HIGH TEMPERATURES WILLS STRUGGLE TO GET OUT OF THE SINGLE
DIGITS OVER WESTERN AREAS. WIND CHILLS THIS WEEKEND WILL BECOME
DANGEROUSLY COLD WITH READINGS DROPPING TO AROUND 30 BELOW ZERO OVER
THE INTERIOR WEST.
SATURDAY NIGHT THROUGH MONDAY...A SURFACE HIGH PRESSURE SYSTEM IS
PROGGED TO MOVE INTO THE UPPER GREAT LAKES REGION AS UPPER LEVEL
FLOW BECOMES SLIGHTLY MORE ZONAL SATURDAY NIGHT THROUGH SUNDAY. THIS
ALONG WITH DRYER AIR WILL ALLOW LAKE EFFECT SNOT TO DIMINISH. LOW
PRESSURE WILL THEN BUILD BACK INTO THE AREA SUNDAY NIGHT INTO
MONDAY. WINDS WILL BECOME SOUTH TO SOUTHWESTERLY DURING THIS TIME
PERIOD WHILE TEMPERATURES ALOFT AT 850MB LINGER AROUND -15C WHICH
WILL HELP LES TO DEVELOP OVER THE FAR EASTERN UPPER PENINSULA AS THE
WIND FLOW WOULD BE DIRECTLY ACROSS THE WARM WATERS OF LAKE MICHIGAN.
THE BEST CHANCE OF THIS HAPPENING WOULD BE SUNDAY NIGHT INTO MONDAY
MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1228 AM EST TUE DEC 3 2013
DISTURBANCE APPROACHING FROM THE NRN PLAINS WILL SPREAD -SN FROM W
TO E ACROSS THE AREA TONIGHT. WITH THE ONSET OF THE -SN...MARGINAL
VFR CONDITIONS WILL INITIALLY LOWER TO MVFR AND THEN TO IFR SEVERAL
HRS LATER. UPSLOPE E-SE FLOW AT KCMX/KSAW WILL LIKELY ALSO AID IN
DETERIORATING CONDITIONS AT THOSE SITES LATE TONIGHT INTO TUE
MORNING. MAY SEE SOME IMPROVEMENT AT KIWD TUE MORNING AND AT
KSAW/KCMX TUE AFTERNOON AS STEADIER -SN SHIFTS E AND NE. ANOTHER
DISTURBANCE APPROACHING FROM THE PLAINS WILL BRING IN ANOTHER SHOT
OF SNOW LATE TUE EVENING WITH CONDITIONS DETERIORATING TO IFR AGAIN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 AM EST TUE DEC 3 2013
EXPECT INCREASING E WINDS THRU TONIGHT AS THE PRES GRADIENT TIGHTENS
OVER THE UPPER LAKES BETWEEN HI PRES OVER NORTHERN ONTARIO AND LO
PRES TAKING SHAPE IN THE PLAINS. THE STRONGEST WINDS WILL BE OVER
WESTERN LAKE SUPERIOR...WHERE THE TERRAIN SURROUNDING THE LAKE
FUNNELS AND ENHANCES THE LARGER SCALE WINDS. MAINTAINED GOING GALE
WARNINGS FOR THE TWO WESTERN ZONES AND MENTIONED SOME GALE FORCE
GUSTS OVER THE CENTRAL AS WELL THIS AFTERNOON THRU TONIGHT.
LOW PRESSURE WILL MOVE ACROSS THE UPPER GREAT LAKES LATE WED THROUGH
THU MORNING. IN THE WAKE OF THE LOW...VERY COLD AIR ADVECTING OVER
THE RELATIVELY WARM WATERS WILL INCREASE INSTABILITY AND RESULT IN W
TO NW GALES AT TIMES FOR PORTIONS OF LAKE SUPERIOR WED NIGHT/THU.
CONTINUED FLOW OF VERY COLD AIR MAY RESULT IN A FEW GALE FORCE GUSTS
INTO SATURDAY BEFORE HIGH PRESSURE BUILDS IN SUNDAY. THIS HIGH
PRESSURE SYSTEM WILL MOVE DIRECTLY OVERHEAD BY SUNDAY AFTERNOON
ALLOW WINDS TO BECOME LIGHT AND VARIABLE. BUILDING WAVES AND THE
ARRIVAL OF THE ARCTIC AIR WILL CAUSE AN INCREASING FREEZING SPRAY
POTENTIAL FOR THE LAST HALF OF THE WORK WEEK AND INTO THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR MIZ009.
LAKE SUPERIOR...
GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 AM
EST /9 AM CST/ WEDNESDAY FOR LSZ162.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST WEDNESDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KEC
AVIATION...VOSS
MARINE...KC/KEC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
341 AM EST TUE DEC 3 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 341 AM EST TUE DEC 3 2013
A WARM FRONT MOVING THROUGH LOWER MICHIGAN WILL BRING LIGHT SNOW
POSSIBLY MIXED WITH SLEET AND FREEZING RAIN THIS MORNING. WE DON/T
EXPECT MUCH IF ANY ACCUMULATION. HOWEVER A FEW ROADS COULD BECOME
SLICK. THE PCPN WILL BECOME LIGHT RAIN THIS AFTERNOON AS WARMER AIR
MOVES INTO THE REGION.
A STRONG COLD FRONT WILL MOVE THROUGH WEDNESDAY NIGHT BRINGING AN
ABRUPT END TO THE 50 DEGREE TEMPERATURES EXPECTED WEDNESDAY. SNOW
SHOWERS AND HIGHS IN THE 20S ARE EXPECTED FRIDAY THROUGH THE
WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
FORECAST CONCERNS DEAL WITH MIXED PCPN MAINLY THIS MORNING.
LATEST RADAR SHOWS A BAND OF PCPN STRETCHING FROM OCEANA COUNTY
SOUTHEAST TOWARD NW OHIO MOVING NEWD THROUGH THE CWA. MOST OF THIS
IS LIGHT SHOW BUT LOCAL OBS HAVE SHOWN SOME SLEET TOO. THIS WAS
CORROBORATED BY DUAL POL. LATEST HRRR AND FCST SOUNDINGS SUGGEST
SOME
LIGHT FREEZING RAIN IS POSSIBLE TOO THIS MORNING BEFORE TEMPS WARM
UP ENOUGH TO RESULT IN LIGHT RAIN. PCPN IS FAIRLY LIGHT AND ANY
ACCUMS SHOULD REMAIN LESS THAN AN INCH. THAT SAID...A FEW ROADS MAY
BECOME SLICK.
A WARM FRONT WILL CONTINUE TO PUSH NORTH THROUGH THE CWA TONIGHT. H8
TEMPS RISING TO 7C SHOULD RESULT IN SFC TEMPS IN THE 50S TOMORROW.
MODELS CONTINUE TO BE AT ODDS ON COLD FRONTAL TIMING. WE/LL BE
CONSISTENT THOUGH IN FOLLOWING THE SLOWER ECMWF DUE TO THE OCCLUDING
NATURE OF THE SYSTEM. THAT MEANS A FROPA WEDNESDAY NIGHT. HIGHS
THURSDAY WILL BE IN THE MID 30S. LIGHT SNOW SHOWERS POSSIBLE
THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
TWO MAIN HEADLINES OF THE LONG TERM REMAIN THE COLD AND LAKE EFFECT
SNOW SHOWERS. THE COLD MAY BE THE BIGGER STORY AS THE LAKE EFFECT
LOOKS TO BE SOMEWHAT MOISTURE DEPLETED.
COLD AIR ADVECTION WILL BE IN FULL SWING THURSDAY NIGHT AS WE BEGIN
THE LONG TERM WITH THE LOW MOVING AWAY ACROSS ONTARIO. DELTA T/S
WILL BE IN THE MIDDLE TEENS...PROVIDING DECENT INSTABILITY. MOISTURE
LOOKS LIMITED SO NOT EXPECTING ANYTHING IN THE WAY OF SIGNIFICANT
LAKE EFFECT. MINOR ACCUMULATIONS AT BEST.
THAT REALLY REMAINS THE CASE FOR FRIDAY THROUGH SATURDAY. CONTINUED
COLD AIR ADVECTION WILL PUSH DELTA T/S INTO THE LOWER 20S C...BUT
MOISTURE REMAINS A LIMITING FACTOR. WE NEVER DEEPLY PLUNGE INTO
CYCLONIC FLOW TO THE NORTH SIDE OF THE UPPER JET AXIS...INSTEAD
REMAINING IN A BROAD SOUTHWEST TO WEST FLOW. 1000-700MB RH VALUES
FROM FRIDAY THROUGH SATURDAY REMAIN IN THE 40-60 PCT RANGE WHICH IS
NOT IDEAL. 20-40 PCT CHANCES FOR SNOW SHOWERS THURSDAY NIGHT THROUGH
SATURDAY SEEM WARRANTED. AT THIS POINT NOT EXPECTING ANY BIG
ACCUMULATIONS...JUST PERSISTENT LIGHT SNOW SHOWERS.
LOW PRESSURE IS FORECAST BY THE ECMWF (STILL THE MODEL OF CHOICE
TONIGHT) TO SWING NORTH THROUGH THE AREA SUNDAY NIGHT INTO MONDAY
WHICH BRINGS A GENERAL LIGHT SYNOPTIC SNOW TO THE AREA.
LOWS IN THE TEENS THROUGH THE PERIOD WITH HIGHS IN THE 20S WILL BE
COMMON. THIS IS COLDER THAN NORMAL...BUT BY NO MEANS RARE FOR EARLY
DECEMBER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1058 PM EST MON DEC 2 2013
THE MAIN AVIATION ISSUE TONIGHT IS WITH THE LIGHT MIXTURE OF
SNOW... FREEZING RAIN.. AND SLEET WHICH IS EXPECTED FROM ROUGHLY
08Z TO 14Z. THIS WILL IMPACT THE MORNING RUSH WITH THE LIKELIHOOD
FOR ICING AS WELL AS SLIPPERY RUNWAY CONDITIONS. THE ICING THREAT
IS EXPECTED TO END BY 15Z AS SFC TEMPS WARM ABOVE FREEZING AND THE
PRECIPITATION CHANGES TO ALL LIGHT RAIN.
WIDESPREAD VFR CONDITIONS AT 04Z WILL LOWER FAIRLY QUICKLY INTO
THE MVFR/IFR CATEGORY 06Z-09Z AS THE LIGHT WINTRY MIX DEVELOPS AND
SPREADS EAST/NORTHEAST. PRECIPITATION WILL CHANGE TO ALL RAIN BY
MID MORNING TUESDAY ALTHOUGH WIDESPREAD IFR CONDITIONS ARE EXPECTED
FOR TUESDAY AFTERNOON AND EVENING DUE TO PERSISTENT LOW CIGS/VSBYS
IN LINGERING LIGHT RAIN/FOG.
&&
.MARINE...
ISSUED AT 341 AM EST TUE DEC 3 2013
SOUTH TO SOUTHEAST WINDS WILL INCREASE TO 15 TO 25 KNOTS TODAY. THE
OFFSHORE NATURE OF THE WINDS SHOULD PRECLUDE WAVES FROM GETTING
HIGHER THAN 3 FEET.
&&
.HYDROLOGY...
ISSUED AT 341 AM EST TUE DEC 3 2013
NO HYDRO ISSUES TODAY. HOWEVER THE ARCTIC AIR EXPECTED BY THE END OF
THE WEEK COULD CAUSE ICE TO DEVELOP ON STREAMS AND RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...MEADE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1230 AM EST TUE DEC 3 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 506 PM EST MON DEC 2 2013
MAIN FCST CONCERN IN THE SHORT TERM IS SNOW ACCUMULATIONS WITH A
RATHER PERSISTENT -SN REGIME SETTING UP.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW RELATIVELY ZONAL FLOW
ACROSS THE NRN PLAINS AND UPPER GREAT LAKES. ONE SHORTWAVE HAS MOVED
E OF UPPER MI...ANOTHER IS OVER THE ERN DAKOTAS/WRN MN WHILE A
WELL-DEFINED MID LEVEL LOW IS NOTED OVER THE PACIFIC NW. PCPN
TONIGHT/EARLY TUE WILL BE ASSOCIATED WITH THE SHORTWAVE HEADING INTO
MN...THEN ANOTHER ROUND OF FORCING MAY BEGIN TO OVERSPREAD THE AREA
LATER TUE AS PACIFIC NW SYSTEM EMERGES INTO THE NRN PLAINS.
RELATIVELY MODEST ISENTROPIC ASCENT/WAA REGIME AHEAD OF THE WRN MN
SHORTWAVE IS GENERATING AN AREA OF -SN FROM NE MN ACROSS FAR WRN
UPPER MI INTO NW WI. ANOTHER BAND OF SNOW IS LINED UP JUST AHEAD OF
THE SHORTWAVE TROF AXIS. AS SHORTWAVE AND ASSOCIATED ISENTROPIC
ASCENT SHIFT E...EXPECT -SN TO SPREAD GRADUALLY E ACROSS ROUGHLY THE
W HALF OF UPPER MI TONIGHT. BETTER ASCENT GENERALLY OCCURS OVER FAR
W INTO SRN UPPER MI...BUT TENDS TO WEAKEN WITH TIME...ESPECIALLY
FARTHER E AND NE...AS SHORTWAVE WEAKENS. MAY END UP WITH A PERIOD OF
STEADIER -SN OVER THE FAR W THIS EVENING UNDER WAA REGIME AND THEN
THERE WILL BE ANOTHER PUSH OF STEADIER -SN AS BAND OF SNOW JUST
AHEAD OF SHORTWAVE TROF AXIS SWINGS INTO THE AREA. IN THE END...
GREATEST SNOW ACCUMULATIONS TONIGHT THRU TUE MORNING WILL OCCUR OVER
THE FAR W AND TO SOME EXTENT TOWARD SCNTRL UPPER MI. UTILIZATION OF
MIXING RATIOS ON THE 290K SFC (ROUGHLY BTWN 700-750MB) SUGGESTS
POTENTIAL FOR 4-6 INCH ACCUMULATIONS ACROSS THE W AND SCNTRL TONIGHT
THRU TUE MORNING. HOWEVER...WITH A LACK OF FOCUSED UPWARD MOTION
THRU A RELATIVELY HIGH/NARROW DGZ...SNOW RATIOS WILL BE ON THE LOW
SIDE...PROBABLY SOMETHING LIKE 10-12 TO 1. ALSO...SINCE ISENTROPIC
ASCENT IS NEVER ESPECIALLY STRONG...SNOW ACCUMULATIONS WILL LIKELY
END UP BLO ADVY CRITERIA. ONLY PLACE THAT WILL BE CLOSE TO ADVY IS
IN THE KIWD VCNTY. FOR NOW...WILL HOLD OFF ANY HEADLINES AND MONITOR
TRENDS THIS EVENING. OVERALL TONIGHT/TUE MORNING...EXPECT MORE OF A
PERSISTENT -SN WITH NOT MUCH IN THE WAY OF NOTABLY HEAVIER PERIODS
OF SNOW.
ON TUE...AREA OF DIMINISHING -SN ASSOCIATED WITH WEAKENING SHORTWAVE
WILL CONTINUE TO LIFT N AND E. MEANWHILE...SYSTEM CURRENTLY OVER THE
PACIFIC NW WILL EMERGE OVER THE NRN PLAINS. AS IT DOES SO...
ISENTROPIC ASCENT MAY STRENGTHEN AGAIN IN THE AFTN OR INTO TUE
EVENING...THOUGH THERE IS SOME DISAGREEMENT ON HOW STRONG THE
ISENTROPIC ASCENT WILL BE. SO...AFTER DIMINISHING -SN INTO THE AFTN
HRS...-SN MAY PICK UP AGAIN FROM THE SW LATER IN THE AFTN. MAY SEE
AN INCH OR SO OF SNOW LATE IN THE DAY TOWARD THE WI BORDER.
SPECIAL WEATHER STATEMENT HAS BEEN UPDATED TO REFLECT THE LATEST
THINKING ON THE WINTRY WEATHER EXPECTED OVER THE NEXT FEW DAYS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 513 PM EST MON DEC 2 2013
SIGNIFICANT SNOWFALL IS POSSIBLE TUESDAY NIGHT INTO THURSDAY MORNING
FOR WEST AND CENTRAL UPPER MICHIGAN
AND THE SAGA CONTINUES...MODELS DISAGREEING ON HOW AND WHEN THE LOW
PRESSURE SYSTEM WILL CROSS UPPER MI. THOUGH ALL HAVE SIMILAR TRACKS
WITH SLIGHT DIFFERENCES...THE 12Z GFS/NAM AND THE 12Z GEM/12Z ECMWF
ARE WIDELY DIFFERENT IN TERMS OF TIMING.
ON THE TRACK OVERALL...MODELS TAKE THE LOW FROM THE CENTRAL PLAINS
INTO THE JAMES BAY/NORTHERN ONTARIO REGION. THE 12Z GEM/12Z
UKMET/12Z ECMWF TAKE THE LOW FURTHEST SOUTHEAST...MOVING FROM
SOUTHEASTERN WI TO EASTERN UPPER MI...THEN INTO ONTARIO SOUTH OF
JAMES BAY. THE GFS/NAM TAKE THE LOW TRACK FROM WESTERN WI INTO
CENTRAL UPPER MI...THEN JUST SOUTH OF JAMES BAY AND NORTHEAST OF
LAKE SUPERIOR.
TIMING WISE...THE 12 GFS/NAM HAVE A MUCH QUICKER SOLUTION THAN THE
ECMWF/GEM...AND THE UKMET IS SLIGHTLY SLOWER THAN ALL. FOR
EXAMPLE...WHEN THE GFS/NAM HAVE THE LOW SOUTH OF JAMES BAY...THE 12Z
ECMWF/12Z GEM ARE JUST CROSSING IT OVER LAKE SUPERIOR/EASTERN UPPER
MI. THE UKMET HAS IT OVER SOUTHEASTERN UPPER MI/NORTHERN LAKE MI.
OVERALL...SINCE CONSISTENCY WISE THE ECWMF SEEMS STEADIER...AND
BECAUSE OFTEN TIMES THE GFS SEEMS TO RUSH THINGS THROUGH/AMPLIFY
THINGS...OPTED TO LEAN TOWARDS THE SLOWER GEM/ECMWF SOLUTION FOR
TIMING. FOR THE EXACT TRACK OF THE LOW...USED A 12Z GEM/12Z ECMWF
COMPROMISE.
USING THE CHOSEN MODEL TRACKS/TIMING...A BROAD AREA OF 850MB WAA AND
ISENTROPIC ASCENT ON THE 290K SFC WILL BRING WIDESPREAD
PRECIPITATION ACROSS UPPER MICHIGAN AS THE SYSTEM APPROACHES TUESDAY
NIGHT THROUGH WEDNESDAY MORNING. SOUNDINGS SUGGEST THIS FIRST BURST
OF PRECIPITATION WILL BE IN THE FORM OF SNOW. BY WEDNESDAY
AFTERNOON...AS THE LOW REACHES IOWA AND ILLINOIS/SOUTHERN WI...WARM
MOIST AIR WRAPPING AROUND THE SURFACE LOW DEVELOPS A 700MB FGEN BAND
THAT ALIGNS ITSELF SOUTHWEST TO NORTHEAST...FROM SOUTHEASTERN MN TO
JUST NORTHEAST OF LAKE SUPERIOR...ACROSS THE WESTERN AND CENTRAL CWA.
BY 00Z THURSDAY SLIGHT DIFFERENCES IN THE TRACK OF THE LOW BETWEEN
THE GEM/ECMWF START TO AFFECT THE TEMPERATURE/PTYPE FORECAST. THE
12Z ECMWF CENTERS THE LOW OVER CENTRAL WI...WHICH BRINGS A NOSE OF
WARMER AIR SLIGHTLY FURTHER NORTH AND CENTRAL. THIS WOULD BRING
CHANCES FOR MIXED PRECIPITATION/RAIN INTO THE NORTH CENTRAL AND
EAST. THE GEM KEEPS THE LOW SOUTHEAST...CENTERED OVER SOUTHEASTERN
WI BY 00Z THUR AND NOT QUITE PULLING THAT WARMER AIR AROUND INTO THE
CENTRAL. THIS WOULD KEEP THE WEST AND NORTH CENTRAL ALL SNOW...AND
THE EAST A MIX/RAIN. BY 12Z THURSDAY HOWEVER...THE MODELS ALL AGREE
ON SNOW BEING THE PTYPE. THE EXACT TRACK WILL AFFECT WHAT TYPE OF
SNOWFALL AMOUNTS WE SEE. AGAIN...WENT WITH AN ECMWF/GEM COMPROMISE
FOR TEMPS/PTYPE...WHICH KEEPS THE PRECIPITATION SNOW FOR A MAJORITY
OF THE FORECAST AREA...ONLY MIXING/RAIN ACROSS THE FAR SOUTHEASTERN
CWA. OVERALL...ACCUMULATIONS COULD BE OVER 6-8 INCHES ACROSS THE
WEST AND CENTRAL U.P. FROM TUESDAY NIGHT INTO THURSDAY MORNING.
AS THE LOW MOVES OFF INTO ONTARIO JUST NORTHEAST OF LAKE SUPERIOR
BETWEEN 06Z AND 12Z THURSDAY...UPPER MICHIGAN IS QUICKLY BROUGHT
INTO AN AREA OF STRONG CAA ON WEST TO NORTHWEST WINDS. 850MB TEMPS
QUICKLY DIP INTO THE -15 TO -20C RANGE IN THE WAKE OF THE LOW...AND
ON ON WEST TO NORTHWEST WINDS LAKE EFFECT CHANCES QUICKLY BECOME THE
MAIN CONCERN. GRADUALLY AS THE LOW HOVERS OVER JAMES BAY AREA FRIDAY
AND SATURDAY...850MB TEMPS CONTINUE TO DROP...REACHING AS LOW AS
-22C...WITH THE KEWEENAW AND WESTERN UPPER MI IN THE COLDEST OF THAT
AIR. THIS WILL BRING VERY COLD TEMPERATURES TO UPPER MICHIGAN FRIDAY
NIGHT THROUGH SATURDAY NIGHT...WITH WIND CHILLS AS LOW AS -25C IN
SOME PLACES OUT WEST.
SATURDAY AND SUNDAY...HIGH PRESSURE STEADILY EXPANDING FROM THE
CANADIAN PRAIRIE...ACROSS THE GREAT LAKES...AND INTO THE ATLANTIC.
GENERALLY IN THIS TIME FRAME...WINDS ARE WESTERLY TO
NORTHWESTERLY...850MB TEMPS RANGE FROM -22C TO -15C...AND THERE ARE
SHORTWAVES ROUNDING THE LOW OVER JAMES BAY. THESE SHORTWAVES WILL
SERVE TO ASSIST THE EXPECTED LAKE EFFECT SNOW SHOWERS DURING THESE
PERIODS...WITH CHANCES LESSENING AS THE LOW DEPARTS AND THE HIGH
STRENGTHENS. SNOW ACCUMULATIONS COULD BE HAMPERED HOWEVER...AS THE
DGZ DIPS CLOSER TO THE GROUND WITH THE EXTREME COLD. ON MONDAY
MODELS DISAGREE SLIGHTLY ON ANOTHER AREA OF LOW PRESSURE MOVING INTO
THE GREAT LAKES REGION...SO KEPT CONSENSUS PRECIPITATION CHANCES
BEGINNING ACROSS THE NON-LAKE EFFECT AREAS AS IT APPROACHES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1228 AM EST TUE DEC 3 2013
DISTURBANCE APPROACHING FROM THE NRN PLAINS WILL SPREAD -SN FROM W
TO E ACROSS THE AREA TONIGHT. WITH THE ONSET OF THE -SN...MARGINAL
VFR CONDITIONS WILL INITIALLY LOWER TO MVFR AND THEN TO IFR SEVERAL
HRS LATER. UPSLOPE E-SE FLOW AT KCMX/KSAW WILL LIKELY ALSO AID IN
DETERIORATING CONDITIONS AT THOSE SITES LATE TONIGHT INTO TUE
MORNING. MAY SEE SOME IMPROVEMENT AT KIWD TUE MORNING AND AT
KSAW/KCMX TUE AFTERNOON AS STEADIER -SN SHIFTS E AND NE. ANOTHER
DISTURBANCE APPROACHING FROM THE PLAINS WILL BRING IN ANOTHER SHOT
OF SNOW LATE TUE EVENING WITH CONDITIONS DETERIORATING TO IFR AGAIN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 506 PM EST MON DEC 2 2013
AS LOW PRES BEGINS TO ORGANIZE IN THE PLAINS AND HIGH PRES BUILDS
ACROSS CNTRL CANADA AND INTO NRN ONTARIO...E TO SE WINDS WILL BE ON
THE INCREASE TONIGHT...AND E WINDS WILL INCREASE FURTHER TUE. EXPECT
WINDS TO REACH GALE FORCE OVER WRN LAKE SUPERIOR TUE AFTN THU WED
MORNING AS TERRAIN SURROUNDING THE LAKE ENHANCES THE E FLOW. THE LOW
WILL MOVE ACROSS THE UPPER GREAT LAKES LATE WED. IN THE WAKE OF THE
LOW...VERY COLD AIR ADVECTING OVER THE RELATIVELY WARM WATERS WILL
INCREASE INSTABILITY AND RESULT IN W TO NW GALES AT TIMES FOR
PORTIONS OF LAKE SUPERIOR WED NIGHT/THU. CONTINUED FLOW OF VERY COLD
AIR MAY RESULT IN PERIODIC GALES EVEN THRU FRI/SAT. BUILDING WAVES
AND THE ARRIVAL OF THE ARCTIC AIR WILL ALSO CAUSE INCREASING
FREEZING SPRAY LATE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 AM
EST /9 AM CST/ WEDNESDAY FOR LSZ162.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST WEDNESDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...MCD
AVIATION...VOSS
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1134 PM CST MON DEC 2 2013
.UPDATE...
ISSUED AT 1134 PM CST MON DEC 2 2013
ONLY CHANGE FOR THE EARLY AM UPDATE WILL BE TO CUT BACK ON QPF FOR
12Z TO 18Z TIMEFRAME ABOUT 50 PER CENT AND 18Z TO 00Z TIME FRAME
ABOUT 20 PER CENT AS ONE THING THE MODELS ACTUALLY **ARE** IN
AGREEMENT WITH IS A LULL IN ACTIVITY THROUGH MUCH OF THE DAY
TOMORROW. DO SEE CLOUDY SKIES AND A VERY...VERY LIGHT SNOW (BUT
HIGH POP) SCENARIO...BUT THAT WILL NOT AMT TO MUCH IN TERMS OF
QPF. RERAN SNOW TOTALS FOR WAVE TWO AND THIS BRINGS US DOWN TO A
VERY LOW END WARNING OF SIX TO EIGHT INCHES ACROSS ALL BUT THE
NORTHERN TIER OF ZONES ALONG THE INTL BORDER...WHICH WOULD BE HIGH
END ADVISORY IN THE FOUR TO SIX RANGE. HOWEVER...MODELS STILL
DIFFERING QUITE A BIT AND PUSHING PRECIP FURTHER SOUTH. THIS
GRADIENT COULD BE EVEN TIGHTER WITH VERY LITTLE AT ALL ACROSS THE
FAR NORTH. STILL ENOUGH UNCERTAINTY WITH 00Z RUNS AND TIME TO
ASSESS 12Z RUNS TOMORROW BEFORE MAKING ANY FINAL DECISIONS ON
HEADLINES...BUT CAN EXPECT VERY LITTLE IMPACT THROUGH 18Z TOMORROW.
UPDATE ISSUED AT 927 PM CST MON DEC 2 2013
THE FOCUS FOR THE 10 PM UPDATE WILL BE THE ISSUANCE OF A WINTER
STORM WARNING FOR THE SOUTHEAST...MAINLY SOUTHERN BELTRAMI THROUGH
WADENA COUNTY AND EASTERN PORTIONS OF BECKER...CLEARWATER...AND
OTTER TAIL.
STORM TOTALS AT THE BEGINNING OF EVENING SHIFT WERE AROUND 5 TO 6
INCHES AND RADAR TRENDS AND THE LATEST RAP GUIDANCE INDICATED THE
EVENT SHOULD END AROUND 11 PM. HRRR WAS A BIT SLOWER...PULLING
PRECIP OUT AROUND 1 AM. HOWEVER...WITH RADAR COVERAGE EXTREMELY
POOR IN THIS AREA DUE TO DISTANCE/OVERSHOOTING ISSUES...HAVE HAD
TO MAKE A PLETHORA OF CALLS IN THE AREA. WE ARE NOW RECEIVING
REPORTS IN THE 6 TO 8 INCH RANGE WITH AN ISOLATED REPORT AROUND 9.
REPORTS FROM THE WADENA AREA INDICATE THE SNOW IS STILL COMING
DOWN AT A DECENT RATE OF AN INCH PER HOUR. AFTER COORDINATION WITH
DLH OFFICE...WILL BE ISSUING A WINTER STORM WARNING FOR THE AREA.
TOTAL ACCUMULATION MAY GET TO THE 8 TO 10 INCH RANGE WITH ISOLATED
AMOUNTS SLIGHTLY HIGHER. THE NAM IS INDICATING A NARROW BAND OF
INCREASED 280K ISENTROPIC LIFT OVER THE AREA. WARNING WILL BE IN
EFFECT UNTIL 12Z.
IT IS VERY IMPORTANT TO REALIZE THE WARNING IS PART OF THE FIRST
WAVE OF SNOW THAT HAS BEEN ADVERTISED...AND WILL BE FOLLOWED BY A
WINTER STORM WATCH FOR THE SECOND WAVE THAT WILL IMPACT THE AREA
FROM MID DAY TUESDAY THROUGH MUCH OF THE DAY WEDNESDAY. ONLY MINOR
UPDATES TO THE GRIDS FOR THE 2ND WAVE...ALTHOUGH HAVE EXPANDED THE
AREA OF LOWER POPS FOR THE LULL IN ACTIVITY EXPECTED ACROSS THE
SOUTH FOR THE REMAINDER OF TONIGHT THROUGH MID DAY TUESDAY.
UPDATE ISSUED AT 648 PM CST MON DEC 2 2013
FOCUS FOR EVENING UPDATE WILL BE TO EXTEND FAR SOUTHERN ZONES
(RANSOM/SARGENT THROUGH GRANT) WINTER WEATHER ADVISORY THROUGH 12Z
TO MATCH REST OF HEADLINES. AREA WAS SET TO EXPIRE AT
00Z...HOWEVER WEAK ECHOES MOVING INTO REGION AS WELL AS SOUNDINGS
INDICATING POSSIBILITY OF SOME FREEZING DRIZZLE...WOULD PREFER TO
EXTEND IN TIME WITH WEATHER OVER THE REGION CONTINUING. SNOWFALL
CONTINUES MAINLY ALONG AND NORTH OF I 94 CORRIDOR WITH SOME SITES
NOW REPORTING SIX INCHES (BJI AND PKD). CHECKING NOW TO SEE HOW
WIDESPREAD THE SIX INCH REPORTS ARE TO DETERMINE IF HEADLINES
SHOULD BE UPDATED. MORE DIFFICULT TO DETERMINE IN THIS AREA AS
RADAR OVERSHOOTS SNOW IN THE BJI AREA...SO MAINLY WILL GO OFF WEB
CAMS AND PUBLIC REPORTS. STAY TUNED FOR MORE INFO IN THIS REGION.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 321 PM CST MON DEC 2 2013
PRECIP TYPE...SNOW AMOUNTS AND WHAT TO DO WITH HEADLINES CONTINUE
TO BE THE PRIMARY FORECAST HEADACHES FOR THE PERIOD.
MAIN UPPER LOW IS STILL DIGGING INTO THE PAC NW THIS
AFTERNOON...WITH ONLY PARTIAL RAOB SAMPLING FOR THE INITIALIZATION
OF THE 12Z MODEL RUNS THIS MORNING. MODEL CONSISTENCY HAS
CONTINUED TO BE POOR EVEN IN THE FIRST 24 HOURS OF THE RUNS. SNOW
BAND FROM THE LEAD SHORTWAVE TODAY HAS BROUGHT 3 TO 6 INCHES OF
ACCUMULATION FROM WEST OF FARGO TO NEAR ALEX. HOWEVER...THE BAND
HAS BEEN WEAKENING AS IT MOVES NORTHEASTWARD. THINK THAT SNOW
ACCUMULATIONS NORTH OF THE I-94 CORRIDOR WILL BE FAIRLY LIGHT AND
MAY ONLY BE AN INCH OR TWO. HOWEVER...THERE IS STILL A LOT OF
SLICK ROADS AND SOME OF THE MODELS SOUNDINGS ACROSS THE SOUTHERN
COUNTIES SHOW THE POSSIBILITY OF SOME FREEZING DRIZZLE. WILL
CONTINUE TO KEEP THE WINTER WEATHER ADVISORY GOING OVERNIGHT.
FOR TOMORROW...THE MODELS SHOW THE FIRST UPPER SHORTWAVE EJECTING
NORTHEASTWARD INTO THE DAKOTAS TUESDAY WHILE THE NEXT SHORTWAVE
DIGS FURTHER SOUTH AND DOES NOT MOVE EASTWARD UNTIL MID WEEK.
THERE IS STILL DISAGREEMENT ON THE EXACT TRACK OF THE SFC
LOW. ALL START IT OFF AS AN INVERTED TROUGH OVER SOUTHERN
MN...WITH A DECENT PRECIP BAND OVER THE CWA AND WINDS STARTING TO
PICK UP. HOWEVER...WHEN THE MODELS CLOSE THE LOW OFF AND HOW FAR
WEST REMAINS IN QUESTION. THE ECMWF HAS TRENDED FARTHER SOUTH WITH
THE HEAVY SNOW BAND WITH EACH RUN...AND THE GFS AND 12Z NAM ALSO
SEEM TO BE FARTHER SOUTH...ALTHOUGH THE 18Z NAM HAS GONE BACK THE
OTHER DIRECTION. EVEN WITH THE FURTHER NORTH SOLUTION...THE CWA
WILL BE IN A LULL BETWEEN TODAYS LEAD SHORTWAVE AND THE NEXT VORT
MAX...SO CONDITIONS MAY NOT BE TOO BAD WHEN PEOPLE GET UP IN THE
MORNING. WITH THIS AND ALL THE UNCERTAINTY OF US EVEN GETTING 6
INCHES...WILL MAINTAIN THE WATCH AND HOLD OFF ON ANY UPGRADES FOR
NOW.
TUESDAYS SHORTWAVE WILL MOVE OFF INTO WI TUESDAY NIGHT...WITH SFC
LOW DEEPENING. THE PRESSURE GRADIENT WILL BE PICKING UP AS THE
ARCTIC HIGH DIGS INTO THE NORTHERN ROCKIES. WINDS WILL BE VERY
STRONG LATE TUESDAY INTO TUESDAY NIGHT...AND BLOWING AND DRIFTING
SNOW COULD BE A PROBLEM. WILL CONTINUE TO MAKE MENTION OF THIS IN
THE WSW AND GRIDS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 321 PM CST MON DEC 2 2013
WEDNESDAY...AN UPPER TROUGH WILL CONTINUE OVER THE ROCKIES...WITH
ANOTHER WEAK SHORTWAVE EJECTING INTO THE PLAINS. WILL CONTINUE TO
KEEP HIGH POPS GOING AND STRONG WINDS...AND THE WATCH WILL REMAIN
THROUGH THE PERIOD. THE SFC LOW WILL MOVE OFF TO THE EAST...WITH
THE ARCTIC AIR COMING IN BEHIND IT. TEMPS MAY NOT GET OUT OF THE
SINGLE DIGITS IN THE NORTHWESTERN COUNTIES AND WITH WINDS
CONTINUING THE CHILL FACTOR WILL BE BRUTAL.
FOR WEDNESDAY NIGHT INTO THURSDAY THERE ARE STILL ENOUGH MODEL
DIFFERENCES TO KEEP A LOT OF UNCERTAINTY IN THE FORECAST. THE 12Z
ECMWF STILL HAS A PRETTY DECENT PRESSURE GRADIENT OVER THE FA WHILE
THE 12Z GFS HAS MUCH LESS. FOR NOW WILL KEEP THINGS MIDDLE OF THE
ROAD WITH SOME GUSTINESS LINGERING WED NIGHT AND THEN DIMINISHING
THINGS ON THU. COLDER AIR WILL CONTINUE TO MOVE INTO THE FA WITH
TEMPS HINGING ON CLOUD COVER. RIGHT NOW IT APPEARS LIKE A GOOD
AMOUNT OF CLOUD COVER WILL HOLD OVER THE AREA KEEPING THE REALLY
COLD TEMPS AT BAY. HOWEVER DETERMINING CLOUD AMOUNTS WITH GOOD
ACCURACY THIS FAR OUT IS TOUGH.
BY THU NIGHT INTO MONDAY CLOUD TRENDS AND TEMPS WILL BE THE MAIN
ISSUE. MODELS SEEM TO LINGER SNOW SHOWERS IN THE NORTHEAST FA A LONG
TIME OR GENERALLY FROM THU NIGHT THRU SAT NIGHT. MEANWHILE 850MB
TEMPS DROP WELL INTO THE 20S BELOW ZERO. SFC HIGH PRESSURE WILL TRY
TO BUILD INTO THE FA BY SATURDAY BUT UNTIL THEN THE 12Z ECMWF KEEPS
SUSTAINED WIND SPEEDS ABOVE 10KTS. THEREFORE IT WILL BE HARD TO
REALIZE THE FULL POTENTIAL OF THE COLD AIR. THE HIGH PRESSURE SYSTEM
IS EXPECTED TO SLIDE TO THE EAST SAT NIGHT AS ANOTHER WEAKER SYSTEM
MOVES UP INTO THE FA FROM THE SOUTHWEST. THIS NEXT SYSTEM LOOKS
WEAKER SO SNOW AMOUNTS SHOULD STAY ON THE LIGHTER SIDE. THIS SYSTEM
WOULD ALSO SPREAD MORE CLOUD COVER INTO THE REGION WHICH WOULD
CONTINUE TO MODERATE THE FRIGID AIR OVER THE FA. HOWEVER COLD IS
COLD AND CLOUDS WOULD NOT MODERATE THINGS THAT MUCH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1134 PM CST MON DEC 2 2013
MOST SITES WILL BE IN MVFR RANGE THROUGH EARLY AFTN TUESDAY...WHEN
CIGS WILL GRADUALLY BEGIN SINKING AND NORTHERLY WINDS WILL BEGIN
TO INCREASE AS THE SYSTEM PULLS ACROSS THE PLAINS. HAVE DELAYED
SNOW AT SITES TILL MID TO LATE AFTN. BJI IS THE EXCEPTION...WHICH
COULD SEE SOME LIGHT SNOW AND IFR CIGS OVER THE NEXT 24 HRS AS
LOW LEVEL MOISTURE IS MORE ABUNDANT IN NORTHERN MN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR NDZ006>008-
014>016-024-026>030-038-039-049-052>054.
WINTER STORM WATCH FROM 6 AM CST TUESDAY THROUGH WEDNESDAY
AFTERNOON FOR NDZ006>008-014>016-024-026>030-038-039-049-
052>054.
MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR MNZ001>009-
013>015-022-027-029-030-040.
WINTER STORM WATCH FROM 6 AM CST TUESDAY THROUGH WEDNESDAY
AFTERNOON FOR MNZ001>009-013>017-022>024-027>032-040.
WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR MNZ016-017-023-
024-028-031-032.
&&
$$
UPDATE...SPEICHER
SHORT TERM...JR
LONG TERM...JR/GODON
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS NORMAN OK
1146 PM CST MON DEC 2 2013
.AVIATION...03 DEC 06Z TAF ISSUANCE...
VISIBILITIES DUE TO FOG CONTINUE TO BE THE PRIMARY FORECAST
CONCERN. SITES ACROSS SOUTH CENTRAL AND SERN OK CONTINUE TO DROP
TO 1/4SM. SITES ACROSS CENTRAL OK HAVE BEEN MORE STEADY OVER THE
PAST FEW HOURS...4 TO 5SM. FROM VISUAL AND SAT OBSERVATIONS...
EXPECT VIS TO CONTINUE TO DROP ACROSS CENTRAL OK THROUGH THE
OVERNIGHT HOURS... IMPACTING KOKC AND KOUN...WITH 1/4SM EXPECTED
THROUGH DAY BREAK. ACROSS NRN OK... DO NOT EXPECT THE IMPACTS TO
BE AS GREAT... WITH 3 TO 5SM FOG FOR KPNC THROUGH THE EARLY
MORNING HOURS. HAVE MENTIONS OF LIGHT FOG AS WELL...5SM... FOR
KCSM/KHBR/KLAW/KSPS AS WELL THROUGH THE EARLY MORNING. WINDS WILL
GRADUALLY INCREASE THROUGH TOMORROW AND REMAIN OUT OF THE S/SW
THROUGH THE EVENING.
JTK
&&
.PREV DISCUSSION... /ISSUED 928 PM CST MON DEC 2 2013/
UPDATE...
ADDED GRANT AND GARFIELD COUNTIES TO THE DENSE FOG ADVISORY.
ALSO...NUDGED LOWS DOWN TONIGHT ACROSS PARTS OF NORTHERN
OKLAHOMA. INCREASED CLOUD COVER ACROSS THE AREA TONIGHT.
DISCUSSION...
ADDED THE LOCATIONS MENTIONED ABOVE TO THE DENSE FOG ADVISORY BASED
ON LATEST HRRR MODEL OUTPUT. THE REST OF THE DENSE FOG ADVISORY
IS IN GOOD SHAPE. ADA HAS BEEN REPORTING 1/4SM FG OVER THE PAST
THREE HOURS AND FEEL HIGHLY CONFIDENT THAT THIS DENSE FOG WILL
SPREAD NORTH AND WEST OVER THE NEXT FEW HOURS. THE OKLAHOMA CITY
METRO AREA SHOULD SEE DENSE FOG DEVELOPMENT IN THE FEW HOURS. FOG
MAY NOT BE AS DENSE AS LAST NIGHT ESPECIALLY WITH INCREASING
SURFACE WINDS TO MIX THE AIR AND MORE HIGH LEVEL CLOUDS TO LIMIT
RADIATIONAL COOLING. REGARDLESS...SOME LOCATIONS WILL EXPERIENCE
SIGNIFICANTLY REDUCED VISIBILITIES WHICH WILL AFFECT DRIVERS.
TEMPERATURES WERE LOWERED TONIGHT ACROSS NORTHERN OKLAHOMA WHERE
THEY HAVE ALREADY FALLEN TO PREVIOUSLY FORECAST LOWS. HIGH LEVEL
CLOUD COVER WILL CONTINUE...BUT MAY DIMINISH LATE TONIGHT.
KEPT THE CURRENT FIRE WEATHER WATCH FOR PARTS OF WESTERN AND
SOUTHWESTERN OKLAHOMA AS WELL AS WESTERN NORTH TEXAS TUESDAY
AFTERNOON...THOUGH WINDS APPEAR TO BE MARGINAL BASED ON LATEST
MODEL OUTPUT.
MBS
PREV DISCUSSION... /ISSUED 521 PM CST MON DEC 2 2013/
UPDATE...
ISSUED A DENSE FOG ADVISORY FROM 7 PM TONIGHT TO 10 AM TUESDAY
ROUGHLY ALONG AND EAST OF I-35.
DISCUSSION...
DENSE FOG WILL AGAIN DEVELOP TONIGHT IN THE OKLAHOMA CITY...
DURANT...ARDMORE...PAULS VALLEY...STILLWATER...AND PONCA
CITY AREAS. LATEST HRRR RUNS HAVE BEEN CONSISTENT WITH DEVELOPING
DENSE FOG DEVELOPING AROUND 7 PM THIS EVENING AROUND COALGATE AND
ATOKA THEN EXPANDING IT NORTH AND WEST...WHICH SEEMS REASONABLE.
THE DENSE FOG SHOULD ARRIVE IN THE OKLAHOMA CITY METRO AREA
BETWEEN 10 PM AND 1 AM.
VISIBILITIES WILL BE 1/4 MILE OR LESS IN MANY LOCATIONS IN
THE ADVISORY AREA LATE TONIGHT INTO TUESDAY MORNING...BUT MAY
NOT BE QUITE AS LOW COMPARED TO LAST NIGHT/THIS MORNING DUE TO
A SLIGHT INCREASE IN SURFACE WINDS. ANY FOG SHOULD DISSIPATE
QUICKER TUESDAY MORNING COMPARED TO THIS MORNING DUE TO THE
STRONGER WINDS.
PRODUCTS HAVE BEEN UPDATED.
MBS
PREV DISCUSSION... /ISSUED 334 PM CST MON DEC 2 2013/
DISCUSSION...
DENSE FOG IS EXPECTED TO DEVELOP AGAIN TONIGHT...MAINLY NEAR AND
EAST OF INTERSTATE-35. DENSE FOG ADVISORIES WILL BE ISSUED LATER
THIS EVENING AS NEEDED. WE DO EXPECT THE FOG TO BURN OFF QUICKER
TOMORROW WITH INCREASING S/SW FLOW.
WRF RUNS NOW EXTENDING INTO BEGINNING OF UPCOMING STORM AND
INITIALLY ARE FORECASTING IMPACTS CLOSER TO GFS...A WETTER AND
HIGHER IMPACT SCENARIO. THE ECM STILL STICKING TO ITS FORECAST OF
LESS ACCUMULATIONS. HISTORICALLY...FOR THE EXCESSIVE ICE EVENTS WE
TYPICALLY SEE DEEP ZONE OF STRONG WARM ADVECTION/LLJ ALONG
ELEVATED BAROCLINIC ZONE/TOP OF THE FRONT/AND THIS IS NOT READILY
APPARENT HERE. STRONG/VERY STRONG MID AND UPPER LEVEL JET DYNAMICS
FORCING RESPONSE WELL ABOVE FRONTAL SURFACE IN THE FORM OF
700-600MB WAA AND FRONTOGENESIS. COINCIDENCE OF THIS FORCING AND
AVAILABLE MOISTURE/DRY-AIR ENTRAINMENT STILL LEAD US TO QUESTION
THE WIDESPREAD HIGH QPFS FROM A FEW OF THE MODELS. NONETHELESS...
GIVEN TRANSIENT TIME OF UPPER JET AND AGREEMENT OF PRECIPITATION
BAND LOCATION FROM ALL MODELS...THERE WILL LIKELY BE A NARROW BAND
OF ENHANCED PRECIP NEAR OR JUST SOUTH OF THE I-44 CORRIDOR. THE
CLOSER TO I-44 THE GREATER CHANCE FOR HEAVY SNOW. FARTHER
SOUTH...FREEZING RAIN AND ICE ACCUMULATION.
STILL LOOKS LIKE EVENT WILL BE ASSOCIATED WITH INITIAL SHIELD OF
RAIN/FREEZING RAIN WESTERN NORTH TEXAS AND SOUTHERN HALF OF
OKLAHOMA LATE WEDNESDAY NIGHT THROUGH THURSDAY. SECOND IMPULSE
INDUCES POSSIBLY HEAVIER PRECIP OVER LARGER AREA LATE THURSDAY
NIGHT THROUGH MIDDAY FRIDAY. APPEARS THAT LEAST AMOUNT OF IMPACTS
WILL BE OVER FAR NORTHERN OKLAHOMA. MODEL TRENDS WILL BE WATCHED
CLOSELY AND IF TRENDS CONTINUE WINTER STORM WATCH WILL LIKELY BE
ISSUED IN THE NEXT COUPLE OF FORECAST PACKAGES.
LIGHT SNOW AND/OR FLURRIES ALONG WITH VERY COLD CONDITIONS WILL
CONTINUE THROUGH THE WEEKEND BUT LITTLE IN THE WAY OF
ACCUMULATIONS EXPECTED SATURDAY AND SUNDAY.
03
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 41 68 35 43 / 0 0 0 0
HOBART OK 38 69 33 45 / 0 0 0 0
WICHITA FALLS TX 40 76 38 52 / 0 0 0 0
GAGE OK 33 68 26 35 / 0 0 0 0
PONCA CITY OK 36 65 31 40 / 0 0 0 0
DURANT OK 45 70 46 54 / 0 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...DENSE FOG ADVISORY UNTIL 10 AM CST TUESDAY FOR OKZ007-008-012-
013-018>020-024>032-039>043-045>048-050>052.
FIRE WEATHER WATCH TUESDAY AFTERNOON FOR OKZ014-016-021-022-
033>038-044.
TX...FIRE WEATHER WATCH TUESDAY AFTERNOON FOR TXZ083>089.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1139 PM CST MON DEC 2 2013
.UPDATE...
ISSUED AT 1138 PM CST MON DEC 2 2013
DRIZZLE CONTINUES TO BECOME MORE AND MORE WIDESPREAD WEST OF THE
SNOW BAND CURRENTLY LOCATED FROM MEDFORD TO MARSHFILED WISCONSIN.
USING THE 03.04Z RAP GUIDANCE...WHICH SEEMS TO BE NAILING THE
FORECAST...THE 285K ISENTROPIC SURFACE INDICATES VERTICAL MOTION
TO CONTINUE UNDER SOUTH-SOUTHWEST FLOW UP THE SURFACE FOR SEVERAL
HOURS. THIS LIFT IS CENTERED ON TAYLOR-ADAMS COUNTIES THROUGH 10Z
BEFORE PULLING EAST.
HAVE UPDATED THE FORECAST FOR WI WITH WIDESPREAD DRIZZLE OVERNIGHT
AND FREEZING DRIZZLE NORTHEAST OF I-94. DO HAVE CONCERNS FOR ICING
OVERNIGHT NORTHEAST OF I-94 AND HAVE ISSUED AN SPS...UPDATED THE
GRAPHICAL WEATHER STORY...AND THE HAZ WEATHER OUTLOOK TO RAISE
AWARENESS.
UPDATE ISSUED AT 955 PM CST MON DEC 2 2013
A COUPLE OF THOUGHTS TO PASS ALONG QUICKLY. THE SNOW BAND ACROSS
CENTRAL WISCONSIN IS EXPECTED TO CONTINUE TO SHIFT
NORTHEAST...HOWEVER WI REMAINS UNDER THE INFLUENCE OF LIFT AND
SOME PRECIPITATION COULD CONTINUE TO FORM BEHIND THE BAND. OVER
THE PAST HOUR...KARX RADAR ECHOES DO STILL SHOW SOME OF THAT LIFT
AS A BAND FORMED ON THE MISS RIVER AND IS NOW ROTATING EAST BEHIND
THE INITIAL RA/SN BAND. UPSTREAM ICE CLOUD IS NOT ROBUST...AND THE
WARM ADVECTION REGION RUNNING FROM KMPX-KMSN ROUGHLY SEEMS THAT IT
COULD PROVIDE SOME LIFT IN THE LOW-LEVELS OVERNIGHT. SO...THE MAIN
CONCERN RIGHT NOW IS THE BAND SHIFTS NE AND THEN LOSS OF ICE CLOUD
WOULD ALLOW THE 2KM DEEP SURFACE-BASED SUPERCOOLED LIQUID LAYER TO
RESIDE WITH RAP/NAM/GFS AGREED ON -5 UB/S UPWARD MOTION. WITH
TEMPERATURES ALONG AND NORTHEAST OF I-94 NEAR OR BELOW FREEZING...THIS
COULD MEAN A FREEZING DRIZZLE PERIOD AFTER MIDNIGHT. WILL START TO
RAMP THE MESSAGE UP A BIT IN NEXT HOUR.
SECOND ITEM IS THE 03.00Z NAM HAS COME IN WITH A SOLUTION MORE
ALONG THE UKMET/ECMWF SOLUTIONS FOR A MORE SOUTHERN SURFACE LOW
PRESSURE TRACK WEDNESDAY AND A SNOWBAND OFF TO THE NORTHWEST. IT
IS LIKELY WE WILL START MOVING THE FORECAST TOWARD THAT EC/UKMET
SOLUTION OVERNIGHT. AT THIS TIME IT LOOKS LIKE THE MOST OF THE
PRECIPITATION WOULD FALL AS RAIN WITH A SNOW BAND WEST OF THE
FORECAST AREA. A MIXED PRECIPITATION TYPE ISSUE MAY BE IN THE
EQUATION...AND WILL EVALUATE OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 345 PM CST MON DEC 2 2013
FOR TONIGHT...A SHORT WAVE TROUGH WILL MOVE SLOWLY EAST INTO
WESTERN WISCONSIN THIS EVENING...AND THROUGH NORTHERN AND CENTRAL
WISCONSIN OVERNIGHT. THE PRECIPITATION ASSOCIATED WITH THIS
SYSTEM SEEMS TO BE TIED WITH THIS WAVE AND MODERATE TO STRONG 900
TO 800 MB FRONTOGENETIC BAND. THIS BAND ALONG WITH THE LATEST RAP
WAS USED TO TIME THE EASTWARD PROGRESSION OF THIS PRECIPITATION
THROUGH THE FORECAST AREA TONIGHT. SOUTH OF INTERSTATE 94...THE
SOUNDINGS SUGGEST THAT MUCH OF THE PRECIPITATION WILL BE MAINLY IN
THE FORM OF RAIN. WHILE THIS IS LIKELY THE CASE...THERE STILL
COULD BE SOME SNOW MIXING IN AT THE ONSET. NORTH OF INTERSTATE
94...THE SOUNDINGS ARE A BIT COLDER AND THEY SUGGEST THAT THE
PRECIPITATION WILL BE MORE SNOW THAN RAIN. MANY OF THE MODELS ARE
SUGGESTING THAT THE QPFS WILL RANGE FROM 0.10 TO 0.20 INCHES WILL
FALL NORTH OF INTERSTATE 94. HOWEVER THESE MODELS HAVE BEEN
OVERDOING THE PRECIPITATION TOTALS ACROSS SOUTHEAST MINNESOTA THIS
AFTERNOON...SO CONFIDENCE IS NOT OVERLY HIGH THAT THESE
PRECIPITATION AMOUNTS WILL BE REALIZED. AS A RESULT...LOWERED THE
PRECIPITATION AMOUNTS SOME. SNOW AMOUNTS WILL BE UP TO 2 INCHES
ACROSS NORTHERN CLARK AND TAYLOR COUNTIES TONIGHT. TOWARD MORNING
THERE IS SOME CONCERN THAT THERE MAY BE SOME LIGHT FREEZING RAIN
ACROSS THESE SAME AREAS AS WE LOSE THE ICE ALOFT BETWEEN 03.09Z
AND 03.15Z. HOWEVER THERE ARE A LOT OF QUESTIONS ON WHETHER ANY
PRECIPITATION WILL BE OCCURRING AT THIS TIME...SO DID NOT ISSUE A
WINTER WEATHER ADVISORY AT THIS TIME.
FROM LATE TUESDAY MORNING INTO THE AFTERNOON...285 TO 300K
ISENTROPIC LIFT AND WARM AIR ADVECTION INCREASES ACROSS THE AREA
AHEAD OF THE APPROACHING SHORT WAVE TROUGH AND SURFACE LOW.
OVERALL THE BEST 850 MB MOISTURE TRANSPORT LOOKS TO BE NORTH OF
THE INTERSTATE 90 CORRIDOR. IN ADDITION...THE WARM FRONT LOOKS
LIKE IT WILL BE CLOSE TO THIS CORRIDOR TOO. AS A RESULT...KEPT THE
HIGHEST PRECIPITATION CHANCES ACROSS THE NORTH. WOULD NOT BE
OVERLY SURPRISED TO SEE NORTHEAST IOWA AND SOUTHWEST WISCONSIN DRY
DURING THE AFTERNOON. THE 02.18Z NAM IS ALREADY SHOWING THIS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 PM CST MON DEC 2 2013
FROM TUESDAY NIGHT INTO THURSDAY...THE 02.00Z MODELS CONTINUE TO
STRUGGLE WITH THE STRENGTH OF A SHORT WAVE EJECTING OUT OF THE
NORTHERN PLAINS. WHILE THERE ARE COME SLIGHT DIFFERENCES IN TIMING
WITH THE GFS AND NAM...THEY ARE IN GOOD AGREEMENT THAT A STRONG
SHORT WAVE TROUGH WILL EJECT OUT OF THE WESTERN UNITED STATES LONG
WAVE TROUGH AND MOVE ACROSS NORTHERN MINNESOTA ON TUESDAY NIGHT
AND WEDNESDAY MORNING. THIS PUSHES AN ARCTIC COLD FRONT THROUGH
THE AREA ON WEDNESDAY MORNING...AND ALSO MOVES THE PRECIPITATION
OUT OF THE AREA BY LATE TUESDAY NIGHT. MEANWHILE THE ECMWF AND GEM
HAVE A MUCH WEAKER SHORT WAVE EJECTING OUT OF THE LONG WAVE
TROUGH DURING THE SAME TIME PERIOD. AS A RESULT...THE UPPER AIR
FLOW REMAINS SOUTHWESTERLY AND THIS SLOWS THE EASTWARD PROGRESS OF
THE ARCTIC COLD FRONT THROUGH THE FORECAST AREA. AS A RESULT THE
TEMPERATURES ARE MUCH WARMER FROM WEDNESDAY INTO THURSDAY MORNING.
IT ALSO ALLOWS ANOTHER BAND OF PRECIPITATION TO MOVE ACROSS THE
AREA FROM WEDNESDAY INTO WEDNESDAY NIGHT ALONG THE COLD FRONT.
UNFORTUNATELY...ALL OF THESE MODELS HAVE BEEN VERY CONSISTENT WITH
THEIR FORECAST SCENARIOS...SO THE FORECAST CONFIDENCE REMAINS
UNUSUALLY LOW FOR THIS TIME PERIOD. SINCE THERE WAS NO CLEAR
CONSENSUS...THE FORECAST WAS TRENDED TOWARD A BLEND OF ALL OF
THEM. WHILE THERE IS A POTENTIAL OF 2 TO 4 INCHES OF SNOW ACROSS
NORTHERN CLARK AND TAYLOR COUNTIES...THE FORECAST CONFIDENCE WAS
TOO LOW TO EVEN ISSUE A WINTER STORM WATCH FOR THIS TIME PERIOD.
FURTHER NORTHWEST WHERE THERE IS A BIT MORE CONSENSUS...A WINTER
STORM WATCH WAS ISSUED.
FROM FRIDAY INTO SATURDAY...THE FORECAST CONFIDENCE IS STILL NOT
THAT HIGH ON THE TEMPERATURES FOR THIS TIME PERIOD. UNLIKE THE
PAST COUPLE OF DAYS...THERE IS NOW A STRIATION IN THE 850 MB
TEMPERATURES ACROSS THE FORECAST AREA. TEMPERATURES ACROSS THE
AREA RANGE FROM -14C ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN
TO -20C IN NORTH CENTRAL WISCONSIN. IN ADDITION...THERE CONTINUES
TO BE QUESTIONS ON WHETHER THERE WILL BE ANY SNOW COVER ACROSS
MUCH OF THE FORECAST AREA. IN AREAS WHICH DO NOT HAVE SNOW
COVER...BOTH HIGHS AND LOW TEMPERATURES WILL BE 10 TO 15 DEGREES
WARMER THAN AREAS /LIKELY NORTH OF INTERSTATE 94/ WHICH HAVE AT
LEAST 1 INCH OF SNOW ON THE GROUND. DUE TO THIS...WENT MORE WITH
THE CONSENSUS OF HIGH TEMPERATURES IN THE SINGLE DIGITS NORTH OF
THE INTERSTATE 94 CORRIDOR AND IN THE TEENS ACROSS THE REMAINDER
OF THE AREA. LOW TEMPERATURES WILL BE IN THE NEGATIVE SINGLE
DIGITS NORTH OF INTERSTATE 94 AND BE IN THE POSITIVE SINGLE
DIGITS ACROSS THE REMAINDER OF THE AREA.
ON SUNDAY AND SUNDAY NIGHT...WEAK WARM AIR ADVECTION AND 275-285K
ISENTROPIC LIFT AHEAD OF AN APPROACHING SHORT WAVE WILL LOWER
CONDENSATION PRESSURE DEFICITS TO LESS THAN 30 MB. THIS SHOULD
RESULT IN THE POTENTIAL FOR SOME LIGHT SNOW OR FLURRIES. DUE TO
THIS...A 15 TO 24 PERCENT CHANCE OF LIGHT SNOW WAS ADDED TO THE
FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1138 PM CST MON DEC 2 2013
STATIONARY FRONT REMAINS PARKED TO THE WEST OF THE TAF SITES WHICH
CONTINUES TO PROVIDE A GOOD ENVIRONMENT FOR LOW CEILINGS. HAVE PUT
A SMALL DIURNAL TREND IN OVERNIGHT WITH SOME LOWERING CIGS/VSBYS
NEAR SUNRISE...BEFORE LIFTING WITH A BIT OF WARMING TUESDAY.
HOWEVER...EDGE TO CLOUDS IS JUST WEST OF KRST AND THIS MAY GET
CLOSE OR WORK IN AT TIMES AT KRST. THIS IS NOT IN THE CURRENT
FORECAST...BUT MAY OCCUR.
HAVE GOOD LIFT OCCURING AT AND EAST OF KLSE OVERNIGHT WHICH WILL
CAUSE DZ TO BE AROUND FOR SEVERAL HOURS OVERNIGHT. TEMPERATURES
WILL REMAIN ABOVE FREEZING SO ICING SHOULD NOT BE AN ISSUE AT
KLSE. ANOTHER PERIOD OF LIFT COMING IN LATE TUESDAY AND INTO
TUESDAY NIGHT WILL PROLONG THE LOW MVFR OR IFR CONDITIONS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BAUMGARDT
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS MIAMI FL
1026 AM EST TUE DEC 3 2013
.UPDATE...
PARTLY CLOUDY TO MOSTLY SUNNY SKIES PREVAIL ACROSS SOUTH FLORIDA
THIS MORNING. A FEW LIGHT SHOWERS ARE CURRENTLY SEEN ACROSS THE
GULF WATERS. LATEST HRRR DEPICTS THESE SHOWERS SPREADING ACROSS
PORTIONS OF THE INTERIOR THROUGH THE AFTERNOON. MADE MINOR TWEAKS
TO THE ONGOING FORECAST. UPDATE SENT.
&&
.PREV DISCUSSION... /ISSUED 554 AM EST TUE DEC 3 2013/
AVIATION...
HIGH PRESSURE WILL KEEP VFR CONDITIONS THROUGH THE TAF PERIOD,
WITH POSSIBLE BRIEF MVFR THIS MORNING DUE TO SOME LOWER CIGS.
HOWEVER, THERE IS A GREAT AMOUNT OF UNCERTAINTY WITH THIS, THUS
BEING LEFT OUT OF THE TAFS AT THIS TIME. THERE IS A MID LEVEL DECK
OF CLOUDS MOVING ACROSS SOUTH FLORIDA THIS MORNING. THIS HAS KEPT
FOG FROM FORMING AND IS EXPECTED TO REMAIN ABOVE 5000 FT.
SKIES SHOULD BEGIN TO CLEAR SOME LATER THIS MORNING, BECOMING A
SCT DECK. WINDS WILL PICK UP OUT OF THE SOUTHEAST BETWEEN 5 AND 10
KTS MID MORNING.
PREV DISCUSSION... /ISSUED 320 AM EST TUE DEC 3 2013/
DISCUSSION...
THE MAIN SURFACE FEATURES ACROSS THE REGION INCLUDE WEAK HIGH
PRESSURE ACROSS THE SOUTHEASTERN GULF THAT EXTENDS INTO SOUTH
FLORIDA AND A WEAK LOW OFF THE COAST OF THE CAROLINAS. THIS
SYNOPTIC SITUATION WILL MAINTAIN LIGHT WINDS ACROSS THE REGION
TODAY WHILE LOW LEVEL MOISTURE AND LOW LEVEL STRATUS CONTINUES TO
LINGER ACROSS THE REGION EARLY THIS MORNING. AT THE UPPER LEVELS A
TROUGH CONTINUES TO BUILD INTO THE WESTERN ATLANTIC TO THE EAST OF
THE SOUTHEASTERN STATES WHILE THE SOUTHERN EXTENT OF THE JET
STREAM IS POSITIONED ACROSS SOUTH FLORIDA AND THE FLORIDA STRAITS
EARLY THIS MORNING. RECENT WATER VAPOR IMAGERY INDICATES DRY MID
TO UPPER LEVEL AIR BUILDING ACROSS MOST OF THE FLORIDA PENINSULA
BUT MOISTURE CONTINUES ACROSS THE SOUTHERN HALF OF SOUTH FLORIDA.
FOR TODAY...GIVEN THE LINGERING MOISTURE IN THE GULF AND THE
AFOREMENTIONED JET STREAM PASSING ACROSS THE REGION THERE MAY BE A
SLIGHT CHANCE OF A FEW SHOWERS ACROSS THE GULF WATERS AND THE
NAPLES METRO AREA...BUT LOW CONFIDENCE AS THE MID TO UPPER LEVELS
WILL CONTINUE A DRYING TREND AS THE DAY CONTINUES. BUT THE
GUIDANCE INDICATES THAT THE LOW LEVEL MOISTURE AND ASSOCIATED
STRATUS WILL LIKELY LINGER ACROSS THE REGION TODAY.
FOR WEDNESDAY THROUGH FRIDAY...BY WEDNESDAY THE JET STREAM IS
FORECAST TO START LIFTING NORTH OF THE REGION WITH A MID TO UPPER
LEVEL RIDGE BUILDING WESTWARD AND SURFACE HIGH PRESSURE WILL BUILD
BACK INTO THE REGION FROM THE WESTERN ATLANTIC. WHILE LOW LEVEL
SOUTHERLY FLOW WILL MAINTAIN LOW LEVEL MOISTURE ACROSS THE
AREA...MAINLY STABLE WEATHER CONDITIONS ARE EXPECTED. HIGH
PRESSURE WILL CONTINUE TO BUILD WESTWARD ACROSS THE FLORIDA PENINSULA
THURSDAY AND FRIDAY WITH STABLE WEATHER CONDITIONS FORECAST TO
CONTINUE.
FOR THE UPCOMING WEEKEND...BY SATURDAY A COLD FRONT IS FORECAST TO
BECOME STATIONARY ACROSS THE SOUTHEAST U.S. WHILE HIGH PRESSURE
REMAINS IN PLACE ACROSS SOUTH FLORIDA AND ADJACENT WATERS WITH
MAINLY STABLE WEATHER FORECAST TO CONTINUE THROUGH THE WEEKEND.
THE EXTENDED GUIDANCE INDICATES THAT THE FRONT COULD ENTER CENTRAL
FLORIDA BY TUESDAY.
MARINE...
WINDS ARE FORECAST TO BE 10 KNOTS OR LESS THROUGH WEDNESDAY WITH
MAINLY TRANQUIL SEAS EXPECTED. BY THURSDAY THE PRESSURE GRADIENT
INCREASES ACROSS THE WESTERN ATLANTIC WITH EASTERLY FLOW IN THE 10
TO 15 KNOT RANGE FORECAST AND IS FORECAST TO PERSIST IN THAT RANGE
INTO THE UPCOMING WEEKEND WITH GULF STREAM SEAS FROM 2 TO 4 FEET
THROUGH THAT PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 79 66 81 69 / - 10 0 10
FORT LAUDERDALE 79 68 81 72 / - 10 0 -
MIAMI 80 68 81 71 / - 10 0 -
NAPLES 78 64 82 65 / 20 10 - 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
646 AM EST TUE DEC 3 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER THE REGION TONIGHT AS LOW
PRESSURE OFF THE COAST MOVES NORTHWARD. THE AREA OF HIGH PRESSURE
WILL MOVE OFF THE COAST TUESDAY ALLOWING A WARM FRONT TO LIFT
NORTH THROUGH THE AREA. A SIGNIFICANT WARMING TREND WILL BEGIN
MIDWEEK WITH A COLD FRONT BRINGING A CHANCE OF RAIN AND COOLER
TEMPERATURES FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PATCHY LIGHT RAIN ASSOCIATED WITH WEAK ISENTROPIC LIFT AND SHORT
WAVE TROUGH CONTINUES TO SPREAD INTO THE WESTERN MIDLANDS EARLY
THIS MORNING. LITTLE PROGRESS EAST DUE TO DRIER AIR MASS...LIMITED
PRECIPITABLE WATER. MORE ORGANIZED AREA OF RAIN OVER CENTRAL
GEORGIA MOVING TOWARD CSRA. LATEST HRRR GUIDANCE SUGGEST IT WILL
HOLD TOGETHER AND MOVE INTO THE AGS AREA. WILL RAISE POPS TO
LIKELY THERE FOR THIS MORNING.
UPPER LEVEL FLOW ZONAL TODAY...WEAK SHORT WAVE TROUGHS WILL MOVE
ACROSS THE REGION. SURFACE RIDGE MOVING OFF THE COAST. WARM FRONT
ACROSS SOUTHERN ALABAMA/SOUTH GEORGIA WILL BE LIFTING TO THE
NORTHEAST DURING THE DAY. WEAK ISENTROPIC LIFT/MOISTURE FLUX WILL
CONTINUE AHEAD OF THE WARM FRONT...ESPECIALLY ACROSS THE WESTERN
MIDLANDS/CSRA. PRECIPITABLE WATER REMAINS LOW...SREF INDICATES LOW
QPF. RAISE POPS FROM PREVIOUS FORECAST. TEMPERATURES SIMILAR TO
YESTERDAY WITH CONSIDERABLE CLOUDS AHEAD OF WARM FRONT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
WITH WARM FRONT LIFTING NORTH ACROSS THE AREA TONIGHT...HIGHEST
POPS DURING THE OVERNIGHT...LIKELY IN THE PIEDMONT/NORTH MIDLANDS
WHERE ISENTROPIC LIFT APPEARS TO BE STRONGEST. TEMPERATURES MAY
RISE TOWARD DAYBREAK. CHANCE SHOWERS EARLY WEDNESDAY BUT EXPECT
BREAKS IN THE CLOUDS BY AFTERNOON WITH DRYING ALOFT...WARM
ADVECTION SUPPORTS ABOVE NORMAL TEMPERATURES IN THE 70S. SHORT
WAVE RIDGE OVER THE AREA LATE WEDNESDAY THROUGH WEDNESDAY NIGHT
SHIFTS OFF THE COAST. UPPER LEVEL RIDGE OFFSHORE SOUTHEASTERN
STATES INTO GULF OF MEXICO IN RESPONSE TO UPSTREAM AMPLIFIED TROUGH
IN THE WESTERN STATES. SURFACE COLD FRONT MOVING INTO THE
TENNESSEE/OHIO VALLEY. WARM ADVECTION/MOISTURE FLUX INCREASING
ACROSS REGION...BEST CHANCE RAIN REMAINS TO THE WEST DUE TO
RIDGING EAST. RAISED POPS SLIGHTLY FROM PREVIOUS FORECAST DUE TO
LIKELY INCREASE IN MOISTURE. TEMPERATURES ABOVE NORMAL IN THE LOW
TO MID 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MEDIUM RANGE MODELS APPEAR TO BE CONVERGING ON A SOLUTION. THE
MAIN FORECAST PROBLEM REVOLVES AROUND THE TIMING OF A COLD FRONT
IN THE FRIDAY NIGHT INTO EARLY SATURDAY PERIOD AND SUBSEQUENT
WEDGE SETUP FOR EARLY NEXT WEEK.
THE MODELS DEPICT A LARGE AND EXPANSIVE UPPER TROUGH ACROSS THE
WESTERN UNITED STATES WITH DOWNSTREAM RIDGING ACROSS THE
SOUTHEASTERN STATES INTO THE MID ATLANTIC REGION. A SLOW MOVING
FRONTAL BOUNDARY IS EXPECTED TO STALL JUST WEST OF THE FORECAST AREA
INTO FRIDAY AS DEEP SOUTHWESTERLY FLOW ALOFT BECOMES NEARLY
PARALLEL TO THE FRONT. BOTH THE GFS AND ECMWF PUSH THE COLD FRONT
THROUGH THE FORECAST AREA FRIDAY NIGHT INTO EARLY SATURDAY... WITH
WEDGE CONDITIONS DEVELOPING SATURDAY AND LINGERING PERHAPS INTO
MONDAY.
INCREASING CHANCES OF RAIN FRIDAY INTO THE WEEKEND.
UNCERTAINTY REMAINS REGARDING THE PRECIPITATION AMOUNT AND EVEN
POSSIBLE THUNDERSTORMS WITH CONSIDERABLE SPREAD IN THE GUIDANCE.
THE SIGNIFICANT WARM UP CONTINUES THURSDAY AND FRIDAY UNDER THE
INFLUENCE OF THE UPPER RIDGE AND DEEP SOUTHERLY FLOW. TEMPERATURES
FALL TO AT OR BELOW NORMAL SATURDAY THROUGH MONDAY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS THROUGH MUCH OF THE PERIOD...WITH LOWERING CONDITIONS
EXPECTED AFTER 03/18Z.
WEAK WARM AIR ADVECTION AND ISENTROPIC ASCENT CONTINUE ACROSS THE
REGION WITH AS A SHORT WAVE TROUGH CURRENTLY CROSSING WESTERN GA.
WIDELY SCATTERED RAIN SHOWERS CONTINUE ACROSS THE AREA AND WILL
CONTINUE TO HANDLE WITH VCSH AS SHOWERS ARE NOT PRODUCING
RESTRICTIONS ATTM. INCREASING CHANCES OF RAIN WILL MOVE INTO THE
TAF SITES THIS AFTERNOON AS THE SHORT WAVE CROSSES THE AREA.
EXPECT CIG RESTRICTIONS BEGINNING BY 21Z AND PERSISTING INTO
TONIGHT. FOG IS ALSO A CONCERN AFTER 04/05Z WITH MODELS INDICATING
INCREASING POTENTIAL. HAVE INCLUDED MVFR IN FOG/STRATUS FROM
AROUND 04/06Z ONWARD AND WILL ADJUST AS CONFIDENCE IMPROVES.
EXTENDED AVIATION OUTLOOK...STRATUS AND FOG WILL LIKELY OCCUR DURING
THE EARLY MORNING HOURS WEDNESDAY AND THURSDAY ASSOCIATED WITH A
WARM FRONT. LOW CONFIDENCE FORECAST FOR FRIDAY AND SATURDAY WITH
PERIODS OF MVFR...AND POSSIBLY LOWER.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
546 AM EST TUE DEC 3 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER THE REGION TONIGHT AS LOW
PRESSURE OFF THE COAST MOVES NORTHWARD. THE AREA OF HIGH PRESSURE
WILL MOVE OFF THE COAST TUESDAY ALLOWING A WARM FRONT TO LIFT
NORTH THROUGH THE AREA. A SIGNIFICANT WARMING TREND WILL BEGIN
MIDWEEK WITH A COLD FRONT BRINGING A CHANCE OF RAIN AND COOLER
TEMPERATURES FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PATCHY LIGHT RAIN ASSOCIATED WITH WEAK ISENTROPIC LIFT AND SHORT
WAVE TROUGH CONTINUES TO SPREAD INTO THE WESTERN MIDLANDS EARLY
THIS MORNING. LITTLE PROGRESS EAST DUE TO DRIER AIR MASS...LIMITED
PRECIPITABLE WATER. MORE ORGANIZED AREA OF RAIN OVER CENTRAL
GEORGIA MOVING TOWARD CSRA. LATEST HRRR GUIDANCE SUGGEST IT WILL
HOLD TOGETHER AND MOVE INTO THE AGS AREA. WILL RAISE POPS TO
LIKELY THERE FOR THIS MORNING.
UPPER LEVEL FLOW ZONAL TODAY...WEAK SHORT WAVE TROUGHS WILL MOVE
ACROSS THE REGION. SURFACE RIDGE MOVING OFF THE COAST. WARM FRONT
ACROSS SOUTHERN ALABAMA/SOUTH GEORGIA WILL BE LIFTING TO THE
NORTHEAST DURING THE DAY. WEAK ISENTROPIC LIFT/MOISTURE FLUX WILL
CONTINUE AHEAD OF THE WARM FRONT...ESPECIALLY ACROSS THE WESTERN
MIDLANDS/CSRA. PRECIPITABLE WATER REMAINS LOW...SREF INDICATES LOW
QPF. RAISE POPS FROM PREVIOUS FORECAST. TEMPERATURES SIMILAR TO
YESTERDAY WITH CONSIDERABLE CLOUDS AHEAD OF WARM FRONT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
WITH WARM FRONT LIFTING NORTH ACROSS THE AREA TONIGHT...HIGHEST
POPS DURING THE OVERNIGHT...LIKELY IN THE PIEDMONT/NORTH MIDLANDS
WHERE ISENTROPIC LIFT APPEARS TO BE STRONGEST. TEMPERATURES MAY
RISE TOWARD DAYBREAK. CHANCE SHOWERS EARLY WEDNESDAY BUT EXPECT
BREAKS IN THE CLOUDS BY AFTERNOON WITH DRYING ALOFT...WARM
ADVECTION SUPPORTS ABOVE NORMAL TEMPERATURES IN THE 70S. SHORT
WAVE RIDGE OVER THE AREA LATE WEDNESDAY THROUGH WEDNESDAY NIGHT
SHIFTS OFF THE COAST. UPPER LEVEL RIDGE OFFSHORE SOUTHEASTERN
STATES INTO GULF OF MEXICO IN RESPONSE TO UPSTREAM AMPLIFIED TROUGH
IN THE WESTERN STATES. SURFACE COLD FRONT MOVING INTO THE
TENNESSEE/OHIO VALLEY. WARM ADVECTION/MOISTURE FLUX INCREASING
ACROSS REGION...BEST CHANCE RAIN REMAINS TO THE WEST DUE TO
RIDGING EAST. RAISED POPS SLIGHTLY FROM PREVIOUS FORECAST DUE TO
LIKELY INCREASE IN MOISTURE. TEMPERATURES ABOVE NORMAL IN THE LOW
TO MID 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MEDIUM RANGE MODELS APPEAR TO BE CONVERGING ON A SOLUTION. THE
MAIN FORECAST PROBLEM REVOLVES AROUND THE TIMING OF A COLD FRONT
IN THE FRIDAY NIGHT INTO EARLY SATURDAY PERIOD AND SUBSEQUENT
WEDGE SETUP FOR EARLY NEXT WEEK.
THE MODELS DEPICT A LARGE AND EXPANSIVE UPPER TROUGH ACROSS THE
WESTERN UNITED STATES WITH DOWNSTREAM RIDGING ACROSS THE
SOUTHEASTERN STATES INTO THE MID ATLANTIC REGION. A SLOW MOVING
FRONTAL BOUNDARY IS EXPECTED TO STALL JUST WEST OF THE FORECAST AREA
INTO FRIDAY AS DEEP SOUTHWESTERLY FLOW ALOFT BECOMES NEARLY
PARALLEL TO THE FRONT. BOTH THE GFS AND ECMWF PUSH THE COLD FRONT
THROUGH THE FORECAST AREA FRIDAY NIGHT INTO EARLY SATURDAY... WITH
WEDGE CONDITIONS DEVELOPING SATURDAY AND LINGERING PERHAPS INTO
MONDAY.
INCREASING CHANCES OF RAIN FRIDAY INTO THE WEEKEND.
UNCERTAINTY REMAINS REGARDING THE PRECIPITATION AMOUNT AND EVEN
POSSIBLE THUNDERSTORMS WITH CONSIDERABLE SPREAD IN THE GUIDANCE.
THE SIGNIFICANT WARM UP CONTINUES THURSDAY AND FRIDAY UNDER THE
INFLUENCE OF THE UPPER RIDGE AND DEEP SOUTHERLY FLOW. TEMPERATURES
FALL TO AT OR BELOW NORMAL SATURDAY THROUGH MONDAY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS THROUGH MUCH OF THE PERIOD...WITH LOWERING CONDITIONS
EXPECTED AFTER 03/18Z.
UPPER LEVEL TROUGH CONTINUES TO SWING OFFSHORE WITH SHORT WAVES
MOVING THROUGH THE REGION. WITH WEAK WARM AIR ADVECTION AND
ISENTROPIC ASCENT EXPECT SOME LIGHT SHOWERS TO CROSS THE TAF SITES
THROUGH THE PERIOD. SHOWERS CURRENTLY MOVING TOWARD THE TAF SITES
ARE LIGHT ENOUGH THAT NO RESTRICTIONS ARE EXPECTED THROUGH THE FIRST
HALF OF THE PERIOD. WITH ADDITIONAL MOISTURE MOVING INTO THE REGION
LATER IN THE PERIOD CIGS WILL BEGIN LOWERING WITH MVFR CIGS ARRIVING
AROUND 03/21Z AND PERSISTING THROUGH THE END OF THE PERIOD.
ADDITIONAL SHOWERS ARE POSSIBLE WITH THE LOWER CIGS...HOWEVER VSBY
RESTRICTIONS ARE NOT EXPECTED AS RAINFALL WITH BE LIGHT.
EXTENDED AVIATION OUTLOOK...STRATUS AND FOG WILL LIKELY OCCUR MAINLY
DURING THE EARLY MORNING HOURS WEDNESDAY AND THURSDAY ASSOCIATED
WITH A WARM FRONT. LOW CONFIDENCE FORECAST FOR FRIDAY AND SATURDAY
WITH PERIODS OF MVFR...AND POSSIBLY LOWER.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
77
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
549 AM CST TUE DEC 3 2013
.DISCUSSION...
330 AM CST
FORECAST FOCUS REMAINS LARGELY ON THE NEAR TERM THIS MORNING...
NAMELY PRECIPITATION AND TEMPERATURE TRENDS TODAY THROUGH WEDNESDAY
AS DEEP LOW PRESSURE SYSTEM DEVELOPS IN RESPONSE TO AMPLIFICATION OF
UPPER TROUGH ACROSS THE WESTERN/CENTRAL CONUS. DAYS 3-7 CONTINUE TO
FEATURE MUCH COLDER THAN AVERAGE TEMPERATURES...WITH THE POTENTIAL
FOR A COUPLE OF LIGHT SNOW EVENTS MAINLY ACROSS THE FAR SOUTHEAST
LATE THURSDAY-FRIDAY...AND FOR MOST OF THE AREA SUNDAY/SUNDAY NIGHT.
00Z RAOB ANALYSIS INDICATES FAIRLY ZONAL FLOW PATTERN ACROSS THE
CENTRAL CONUS...WITH A DEEP SHORT WAVE TROUGH DIGGING SOUTHEAST
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SEVERAL RELATIVELY MINOR
AMPLITUDE SHORT WAVES WERE NOTED DOWNSTREAM ACROSS THE MIDWEST...
EMANATING FROM STRONG JET STREAK DEVELOPS AROUND THE SOUTHERN
PERIPHERY OF THE DIGGING TROUGH. ONE SUCH WAVE WAS NOTED IN WATER
VAPOR IMAGERY OVER THE UPPER MISSISSIPPI VALLEY EARLY THIS
MORNING...WHICH WAS RESPONSIBLE FOR AN AREA OF WARM ADVECTION
PRECIPITATION THAT MOVED ACROSS THE FORECAST AREA OVERNIGHT AND WAS
NOW EAST OF THE REGION. A COUPLE OF MORE SUBTLE MID-LEVEL WAVES WERE
NOTED IN THE SATELLITE IMAGERY...ONE APPROACHING QUICKLY FROM
EASTERN IA...AND THE OTHER UPSTREAM ACROSS WESTERN NEBRASKA. THESE
FEATURES WILL RIPPLE QUICKLY EAST ACROSS THE AREA TODAY...MAINLY
WORKING TO MAINTAIN SOUTHERLY FLOW AND CONTINUED WARM ADVECTION INTO
THE MIDWEST. WHILE SOME SPOTTY LIGHT RAIN IS POSSIBLE WITH ANY OF
THESE SUBTLE FEATURES...UPSTREAM SOUNDINGS FROM OMA/TOP/SGF INDICATE
FAIRLY DRY MID-LEVELS. FORECAST SOUNDINGS MAINTAIN THIS DRY LAYER
ROUGHLY BETWEEN 850-650 MB WHICH SUGGESTS MAINLY SCATTERED LIGHT
RAIN OR SOME DRIZZLE WITH ONLY LIGHT QPF AMOUNTS TODAY-TONIGHT AS
FORCING WITH THESE WAVES ACT ON MOIST LOW LEVELS OR BRIEF POCKETS OF
ENHANCED MID-LEVEL MOISTURE.
WITH ONGOING WARM ADVECTION...SURFACE TEMPERATURES AND DEW POINTS
WILL CONTINUE TO SLOWLY RISE AS A WARM FRONT CURRENTLY LIFTING INTO
CENTRAL ILLINOIS MOVES NORTH. WHILE THE BOUNDARY REMAINS A BIT
DIFFUSE EARLY THIS MORNING...THE FRONT SHOULD SHARPEN AND BEGIN TO
MOVE FASTER LATER TODAY AND TONIGHT AS SURFACE LOW PRESSURE DEEPENS
TO OUR WEST ACROSS THE CENTRAL PLAINS IN RESPONSE TO HEIGHT FALLS
WITH DEEPENING WESTERN TROUGH. MODELS ARE IN FAIRLY GOOD AGREEMENT
THAT THE SURFACE WARM FRONT SHOULD LIFT INTO NORTHERN IL BY LATE
AFTERNOON...WITH THE SOUTHERN AND CENTRAL PARTS OF THE CWA GETTING
INTO THE WARM SECTOR. TEMPS SHOULD REACH THE LOW-MID 50S ALONG AND
SOUTH OF I-80 THIS AFTERNOON...WITH 40S TO THE NORTH. IT WILL REMAIN
VERY MILD TONIGHT AS THE WARM FRONT REACHES THE IL/WI BORDER...WITH
OVERNIGHT LOWS HOLDING IN THE 40S ACROSS THE CWA.
GUIDANCE REMAINS IN TWO SEPARATE CAMPS WITH THE HANDLING OF THE MAIN
SURFACE LOW AND COLD FRONT ON WEDNESDAY...WITH THE DOMESTIC MODELS
REMAINING FASTER AND INITIALLY DEEPER BEYOND 30 HOURS THAN THE UK/EC
AND CANADIAN COUNTERPARTS. THE 00Z RUNS OF THE GFS AND TO A GREATER
EXTENT THE WRF HAVE SLOWED HOWEVER...WHICH LENDS SUPPORT TO OUR
FAVORING THE SLOWER SOLUTION OF THE UKMET/ECMWF AND GEM. THUS
CONTINUE TO FAVOR THE SCENARIO OF THE SURFACE LOW LIFTING ACROSS
EASTERN IOWA INTO WI WEDNESDAY AFTERNOON...AND THE TRAILING COLD
FRONT MOVING ACROSS THE WFO LOT FORECAST AREA FAIRLY LATE IN THE
AFTERNOON AND EVENING HOURS. THIS SUPPORTS TEMPS IN THE 50S...AND
EVEN A COUPLE OF 60S FAR SOUTH...WEDNESDAY WITH THE CWA STILL IN THE
WARM SECTOR AHEAD OF THE FRONT. MID-LEVEL MOISTURE CONTINUES TO BE
LIMITED...AND ALTHOUGH LIGHT RAIN/SHOWER CHANCES DO INCREASE WITH
THE APPROACH OF THE LOW/COLD FRONT THE BEST COVERAGE AND RAINFALL
AMOUNTS EXPECTED NORTH OF THE AREA ACROSS WI AND THE NORTHERN LAKES.
THE COLD FRONT PUSHES ACROSS THE AREA WEDNESDAY EVENING...SHUTTING
OFF PRECIP AS MID/UPPER LEVELS DRY OUT. THANKS TO WEST-SOUTHWEST
FLOW ALOFT THE FIRST PUSH OF COLDER AIR IS RELATIVELY WEAK...AS THE
FRONT AND LOW LEVEL BAROCLINIC ZONE SLOW UP FROM THE OHIO VALLEY TO
THE EASTERN LAKES INTO THURSDAY. A COUPLE OF DISTURBANCES RIPPLE
NORTHEAST ALONG THIS BAROCLINIC ZONE LATE THURSDAY INTO FRIDAY...
WITH THE POTENTIAL FOR SOME LIGHT SNOW FROM CENTRAL IL INTO NORTHERN
INDIANA AND MAINLY CLIPPING THE FAR SOUTHEAST PART OF THE CWA. A
SECOND PUSH OF COLDER AIR THEN SPREADS IN THURSDAY NIGHT-FRIDAY AS
THE UPPER LOW PASSES TO THE NORTH AND HEADS INTO EASTERN CANADA.
THIS ALLOWS 850 MB AIR OF -10 TO -15 C ACROSS THE AREA AND TEMPS A
GOOD 8-10F COLDER FRIDAY THAN ON THURSDAY. SOME DIFFERENCES REMAIN
WITH MODEL DETAILS AT THIS TIME...BUT CONTINUE TO FAVOR THE SIMILAR
GEM/ECMWF WHICH SUPPORTS HIGHS ONLY NEAR/AROUND 20 FRIDAY AND
SATURDAY AS ARCTIC HIGH PRESSURE BUILDS ACROSS THE MIDWEST. LOOKS
LIKE AT LEAST SOME SLIGHT MODERATION SUNDAY-MONDAY AS UPPER TROUGH
AMPLIFIES ACROSS THE WESTERN CONUS/NOAM...WITH AN AREA OF LOW
PRESSURE LIFTING ACROSS THE AREA SUNDAY WITH THE POTENTIAL FOR SOME
LIGHT SNOW.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* IFR CIGS THROUGH THE PERIOD...POSSIBLY BRIEFLY LIFTING OR
SCATTERING THIS AFTERNOON...BEFORE LOWERING/REDEVELOPING LATE
THIS EVENING.
* WIND DIRECTION...SOMEWHAT VARIABLE SE TO S AS WEAK WARM FRONT
LIFTS THROUGH THE AREA AND WASHES OUT.
* POTENTIAL FOR DENSE FOG TONIGHT.
BMD
//DISCUSSION...UPDATED 12Z...
TRICKY FORECAST ON TAP TODAY...WITH IFR CONDITIONS EXPECTED MUCH OF
THE TAF PERIOD. AN ILL-DEFINED WARM FRONTAL BOUNDARY IS DRAPED
ACROSS CENTRAL ILLINOIS AND IS EXPECTED TO GRADUALLY LIFT NORTH
ACROSS THE TERMINALS TODAY. AHEAD OF THE FRONT...IFR CIGS...FOG AND
LIGHT DRIZZLE/RAIN ARE ALL A LIKELIHOOD. WINDS WILL BE OUT OF THE
SE/SSE THROUGH MUCH OF THE DAY...AND MAY VEER BRIEFLY LATE THIS
AFTERNOON AS THE FRONTAL BOUNDARY MAKES IT NEAR THE STATE LINE
BEFORE WASHING OUT. GUIDANCE NOT IN THE BEST AGREEMENT ON WIND
DIRECTION...WITH SOME SUGGESTING WE MAY GO SSW...WHILE MOST KEEP
WIND DIRECTION SSE. ALSO...NAM GUIDANCE SUGGESTS THAT CIGS MAY
BRIEFLY SCATTER OUT SOUTH OF THE FRONT...BUT CONFIDENCE IN THIS
HAPPENING IS TOO LOW TO INCLUDE IN THE TAF AS DEEPENING AREA OF LOW
PRESSURE OVER THE PLAINS WILL BASICALLY CAUSE THE WARM FRONT TO
REORGANIZE BACK TO OUR SOUTH LATE THIS EVENING. THIS BETTER DEFINED
FRONT WILL GRADUALLY LIFT NORTH TOWARDS THE AREA TONIGHT WITH CIGS
EXPECTED TO ONCE AGAIN LOWER AND LIGHT DRIZZLE DEVELOP. THERE IS A
GOOD POSSIBILITY OF DENSE FOG DEVELOPING TONIGHT AS THE FRONTAL
TROUGH NEARS...SIMILAR TO WHAT HAPPENED ACROSS MUCH OF THE MID AND
LOWER MISSISSIPPI VALLEY THIS MORNING. MET/LAV GUIDANCE HITTING THIS
THE HARDEST...BUT FOR NOW WILL STICK WITH MAV/S MORE CONSERVATIVE
FORECAST.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM-HIGH CONFIDENCE IN IFR CIGS THROUGH THIS AFTERNOON. LOW
CONFIDENCE IN CIGS LIFTING TO MVFR OR SCATTERING OUT THIS
AFTERNOON.
* MEDIUM-HIGH CONFIDENCE IN IFR CIGS LATE THIS EVENING AND TONIGHT.
* LOW-MEDIUM CONFIDENCE IN VSBY TRENDS...AND PRECIP CHANCES/TIMING.
* MEDIUM CONFIDENCE IN WIND DIRECTION/SPEED...EXCEPT LOW-MEDIUM
CONFIDENCE IN THE AFTERNOON.
* LOW CONFIDENCE IN DENSE FOG TONIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.MARINE...
239 AM CST
STILL SIGNIFICANT DIFFERENCES IN THE MODELS WITH RESPECT TO LOW
PRESSURE THAT IS EXPECTED TO IMPACT THE LAKES MIDWEEK. GUIDANCE HAS
TRENDED TOWARDS A SLOWER FRONTAL TIMING AND MORE NORTHERLY LOW TRACK
THOUGH...A TYPICAL TREND WHEN THE UPPER AIR PATTERN IS AMPLIFIED.
WITH THAT IN MIND...HAVE BASED FORECAST TIMING ON A BLEND OF THE GEM
AND THE ECWMF WHICH HAVE BEEN FAIRLY CONSISTENT WITH SLOWER TIMING
AND WHICH THE FASTER NCEP GUIDANCE SEEMS TO BE TRENDING TOWARDS. A
DEEPENING AREA OF LOW PRESSURE IS EXPECTED TO LIFT FROM THE CENTRAL
PLAINS TODAY AND TOMORROW...ACROSS LAKE SUPERIOR OR WEDNESDAY NIGHT.
MODERATE SOUTHEAST TO EAST WINDS ARE EXPECTED AHEAD OF THE
LOW...THOUGH STABLE CONDITIONS WILL HELP KEEP THE HIGHER END GUSTS
FROM REACHING THE LAKE SURFACE. BEHIND THE FRONT...STRONG AND COLD
HIGH PRESSURE WILL OVERSPREAD THE PLAINS WITH A TIGHT GRADIENT ONLY
VERY GRADUALLY SUBSIDING THROUGH THE REST OF THE WEEK. THERE MAY BE
A SHORT PERIOD OF WESTERLY GALES IMMEDIATELY BEHIND THE FRONT
WEDNESDAY NIGHT INTO THURSDAY...WITH 30KTS REST OF THURSDAY INTO
FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 3 PM TUESDAY.
&&
$$
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[top]
Area Forecast Discussion
National Weather Service Lincoln IL
533 AM CST Tue Dec 3 2013
.DISCUSSION...
ISSUED 315 AM CST Tue Dec 3 2013
Main forecast concern continues to be potential for accumulating
snow and ice across parts of central Illinois Thursday into Friday.
SHORT TERM...Today through Thursday
Widespread fog blankets central Illinois early this morning,
thanks to light southerly winds and ample low-level moisture
flowing northward behind an advancing warm front. 08z/2am
visibilities are generally in the 2 to 4 mile range, but a few
pockets of locally dense fog are beginning to develop across
west-central and southwest Illinois. HRRR suggests visibilities may
continue to drop across this area over the next few hours. As a
result, will be issuing a Dense Fog Advisory for all locations
along and west of I-55 through 10AM. This may need to be expanded
eastward to include the remainder of the KILX CWA if visibility
trends continue. Fog will be slow to dissipate, but should clear
most of the area by around midday. Due to the fog and clouds
expected today, have trimmed previous high temperature forecast by
a few degrees, with readings ranging from the middle 50s far north
to around 60 degrees far south/southwest.
00z Dec 3 models have come into much better agreement concerning
approaching cold front on Wednesday. While the GFS/NAM remain the
fastest models, both have slowed FROPA considerably and are now
closer to the slower/more consistent ECMWF/GEM. With a clear slowing
trend noted, confidence is growing that front will remain west of
central Illinois until late Wednesday afternoon. As a result, have
boosted temperatures, with highs ranging from the lower 50s west
of the Illinois River to the middle 60s south of I-70. Rain
chances with the front still appear very low, as deepest moisture
remains further south. Will continue with just low chance POPs
during the day, with dry weather returning for all but the far SE
CWA Wednesday night into Thursday morning. Much colder air will
spill into the region behind the cold front, resulting in a 20 to
25 degree temperature drop on Thursday. Highs will range from
around 30 in the Illinois River Valley to around 40 south of I-70.
Wave of low pressure is expected to develop and track along the
departing cold front, spreading wintry precipitation into parts
of central and southeast Illinois late Thursday afternoon and
evening. Airmass will be cold enough to support snow along and
northwest of a Taylorville to Danville line, but things get a
little trickier further south. Both the NAM and GFS show a max
temp in the elevated warm layer of 3C, suggesting partial melting
of ice crystals and mixed phase precip reaching the ground. The
exact type of precip will depend on surface temps. Based on
expected afternoon highs, a mixture of snow and sleet will be
likely along the I-70 corridor, with mainly rain along and south
of highway 50 Thursday afternoon. As deeper colder air arrives,
the precip will change over to mainly snow Thursday night. The
exception will be along and south of highway 50, where warm wedge
aloft will remain strong enough to support sleet and perhaps some
freezing rain. Precip may tend to diminish/come to an end
overnight as initial wave passes to the northeast.
LONG TERM...Friday through Monday
A second wave will track along the slow-moving front on Friday:
however, its main precipitation shield is expected to be a bit
further southeast over the Ohio River Valley. Light snow or
flurries may occur as far northwest as I-55 on Friday, with the
steadier snows focused further south along/south of I-70. By the
time the precip comes to an end Friday afternoon, snowfall of
around 1 inch will be possible along a Jacksonville to Danville
line, with as much as 2 to 3 inches further south along the I-70
corridor.
Once precip shuts off, dry and very cold weather will be on tap
through Saturday with high temps only in the 20s and lows dropping
into the single digits and teens. After that, models are trying to
bring another upper-level disturbance across the region late in
the weekend, possibly bringing a period of light snow
Sunday/Sunday night. Given very dry airmass initially in place, am
skeptical that much snow will fall. Have therefore kept POPs in
the low chance category with only minimal accumulations.
&&
.AVIATION...
ISSUED 525 AM CST Tue Dec 3 2013
Coverage and duration of LIFR/VLIFR cigs and vsbys this morning the
main forecast concern.
Cigs and vsbys continue to slowly deteriorate over our area this
morning as a very mild and moist southerly flow prevails. Not
expecting any great improvement in conditions until after 16z
based on the latest short term guidance from the HRRR and HopWRF-
ARW ensembles, and that may be too optimistic as mid and upper 40
dew points stream north out of Missouri into our area today. Will
keep the LIFR to VLIFR conditions in most areas thru about 16z and
then start a gradual improving trend into the afternoon before the
possibility for more widespread LIFR to VLIFR late tonight.
Surface winds will be mostly out of a southerly direction at 8 to
13 kts today and then winds will back more into a southeast
direction tonight at 6 to 10 kts.
Smith
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY until 10 AM CST this morning FOR ILZ027>031-
036>038-040>043-047>053.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
740 AM EST TUE DEC 3 2013
.UPDATE...
ISSUED AT 739 AM EST TUE DEC 3 2013
OPTED TO ADD SOME PATCHY -FZDZ TO THE FCST FOR LATER THIS MRNG/AFTN
FOR MUCH OF THE W HALF OF UPR MM WITH EXPECTATION THAT MID LVL
DRYING ASSOCIATED WITH DNVA/LARGER SCALE QVECTOR DVGC IN THE WAKE OF
DEPARTING SHRTWV WL DRY OUT THE DGZ LYR IN THE 10-12K FT RANGE. SFC
OBS IN NCENTRAL WI SHOW SOME OF THIS PCPN THERE...SO CONFIDENCE IS
INCREASED THIS WL HAPPEN AS WELL IN THE CWA WITH THE ONSET OF MID
LVL DRYING. EXCLUDED THIS PTYPE OVER THE FAR W WHERE LLVL E-SE FLOW
DOWNSLOPES/DRIES AND OVER THE E HALF WHERE LLVL DRY AIR HAS PROVEN
TO BE MORE RESILIENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 447 AM EST TUE DEC 3 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RELATIVELY WEAK
ZONAL FLOW ALF OVER THE UPR GRT LKS TO THE N OF FASTER POLAR JET
OVER THE SRN 2/3 OF THE CONUS. THERE ARE 2 SHRTWVS OF NOTE EMBEDDED
IN THIS FLOW. THE FIRST IS MOVING E THRU MN AND CAUSING A BAND OF SN
EXTENDING FM NE MN SEWD OVER WRN LK SUP AND INTO CENTRAL WI AS OF
06Z UNDER AREA OF H85-5 QVECTOR CNVGC. THE AXIS OF HIER
REFLECTIVITIES IN WI APPEARS TO BE ORIENTED ALONG THE MOST
IMPRESSIVE ISENTROPIC ASCENT SHOWN ON THE 290K SFC /H7-75/...WHILE
THE MOST IMPRESSIVE RETURNS IN NE MN ALIGN WITH MOST VIGOROUS H85-5
QVECTOR CNVGC. THE 00Z INL/MPX RAOBS SHOW DEEP MSTR THRU THE DEPTH
OF THE TROP. ELY FEED OF DRIER LLVL AIR ASSOCIATED WITH AREA OF
MOCLR SKIES/HI PRES RDG AXIS STILL OVER FAR ERN UPR MI AND LOCATION
OF SHARPER H85 THERMAL PACKING/ISENTROPIC ASCENT TO THE S HAS SO FAR
LIMITED THE ENE EXTENT OF THE PCPN INTO UPR MI...BUT SN APPEARS
POISED TO SPREAD INTO THE WRN CWA PER LATEST SFC OBS/RADAR IMAGERY.
THE VSBY AT IWD FELL UNDER 2 MILES AT 07Z...AND THE VSBY AS CLOSE AS
ASHLAND IN NW WI IS DOWN TO 1/2 MILE. ENE FLOW DOWN WRN LK SUP MAY
BE ENHANCING THE SN INTO THIS AREA. IN THE AREA OVER WRN MN/MUCH OF
THE DAKOTAS UNDER DNVA/DEEP LYR QVECTOR DVGC BEHIND THE MN SHRTWV...
THERE IS LTL IF ANY PCPN FALLING EVEN THOUGH SKIES REMAIN CLDY WITH
QUITE A BIT OF MID LVL DRYING ABV LLVL MSTR SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. FARTHER TO THE W...THE 2ND MORE IMPRESSIVE
SHRTWV OF INTEREST IS MOVING EWD THRU THE NRN ROCKIES. 12HR H3 HGT
FALLS UP TO 200M AND H3 WIND SPEEDS UP TO 100M IN THE ACCOMPANYING
JET CORE ARE ASSOCIATED WITH THIS MORE IMPRESSIVE DISTURBANCE.
MAIN FCST CONCERNS IN THE SHORT TERM PERIOD ARE POPS/EXPECTED SN
ACCUMS THRU THIS MRNG ASSOCIATED WITH THE FIRST SHRTWV IN MN AND
NEED FOR ANY HEADLINES. FOCUS FOR TNGT TURNS TO POPS AND SN AMOUNTS
THAT WL ACCOMPANY THE APRCH OF THE 2ND STRONGER SHRTWV.
TODAY...AS MN SHRTWV TRACKS TO THE E INTO PERSISTENT SFC RDG AXIS
JUST TO THE E OF UPR MI AND AWAY FM TROF DEEPENING OVER THE W...
AREA OF H85-5 QVECTOR CNVGC IS PROGGED TO DIMINISH SGNFTLY BY 18Z
WITH MID LVL DRYING UNDER DVLPG H85-5 QVECTOR DVGC. EXPECT THE HIER
POPS THIS MRNG OVER THE W AND SCENTRAL UNDER THE SHARPER H85-5
QVECTOR CVNGC/SHARPER 295K ISENTROPIC ASCENT/AREA OF H85-7 FGEN.
GIVEN PRESENCE OF 2.5G/KG SPECIFIC HUMIDITY AT THIS LVL...EXPECT UP
TO 3 INCHES OF SN FOR THE 6-9 HR PERIOD OVER THE SW HALF OF THE CWA.
SINCE THE SN IS LIKELY TO FALL A FOR CLOSER TO 12Z HRS AT IWD...UP
TO 4 INCHES MAY ACCUMULATE THERE BEFORE THE PCPN DIMINISHES TOWARD
NOON. ALTHOUGH THE DGZ IS RATHER NARROW...MODELS SHOW FAIRLY
IMPRESSIVE OMEGA IN THIS LYR THAT MAY INCH SN/WATER RATIOS CLOSER
TO 15:1. CONSIDERING THE LO VSBYS REPORTED AT ASHLAND IN THE ABSENCE
OF LAKE ENHANCEMENT WITH THE LARGER SCALE E WIND...OPTED TO ISSUE A
WINTER WX ADVY FOR GOGEBIC COUNTY THRU MID MRNG. OTRW...UPSLOPE E
WIND OFF LK MI MAY CAUSE STEADIER SN TO LINGER LONGER OVER THE
SCENTRAL. SN WL LIKELY MOVE INTO THE E DURING THE AFTN BUT WL BE MUCH
LIGHTER AS THE DYNAMIC SUPPORT FADES AND HITS DRIER AIR.
TNGT...ALTHOUGH THE EARLY EVNG WL FEATURE DNVA/LARGER SCALE QVECTOR
DVGC LEFT IN THE WAKE OF THE DEPARTING/WEAKENING SHRTWV...FAVORED
CNDN MODEL SHOWS AXIS OF SHARPER H85-7 FGEN SUPPORTING BAND OF SN
NOW OVER SDAKOTA IMPACTING MAINLY THE SRN CWA FOR A COUPLE HRS IN
THE LATER EVNG. THE 00Z GFS/ECWMF SHOW A SIMILAR QPF...SO WENT FOR
HI END LIKELY POPS IN THIS AREA BY LATER IN THE EVNG. OVERALL MODEL
QPF UP TO 0.25 INCH WL SUPPORT A FEW INCHES OF SN IN THIS AREA. HIER
POPS/MORE SN MAY ARRIVE LATE OVER THE W AS THE DYNAMICS IN ADVANCE
OF THE SHRTWV MOVING THRU THE NRN ROCKIES PUSH TOWARD THE AREA. BUT
MODELS DISAGREE ON THE TIMING OF THE ARRIVAL OF THE DEEP LYR QVECTOR
CNVGC AS WELL AS INTENSITY OF THE SFC LO THAT MIGHT ACCOMPANY THE
LARGER SCALE FORCING. THE NAM/LOCAL WRF-ARW MODELS ARE THE MOST
AGGRESSIVE AT DEEPENING THE SFC LO AND BRINGING MORE PCPN FARTHER E.
BUT SINCE THE MAIN SHRTWV REMAINS SO FAR TO THE W THRU THE NGT...
SUSPECT THE SLOWER/WEAKER CNDN MODEL IS ON THE RIGHT TRACK. SO WENT
NO HIER THAN LIKELY POPS OVER THE FAR W FOR NOW. THE THERMAL FIELDS
FM THE CNDN MODEL INDICATE ENUF WARM AIR WL ARRIVE TO CAUSE THE SN
TO MIX WITH RA OVER THE FAR SCENTRAL.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EST TUE DEC 3 2013
CONTINUED CHALLENGING FORECAST IN STORE FOR WEDNESDAY THROUGH
WEDNESDAY NIGHT TIME FRAME AS A WINTER WEATHER SYSTEM TAKES AIM AT
THE UPPER GREAT LAKES. VERY COLD AIR IS EXPECTED TO BUILD IN ON THE
BACK SIDE OF THIS SYSTEM ALLOWING FOR VERY COLD TEMPERATURES FRIDAY
NIGHT THROUGH SATURDAY NIGHT.
WEDNESDAY INTO WEDNESDAY NIGHT...SITUATION LOOKS A BIT BETTER FROM A
FORECASTING STANDPOINT AS MODELS ARE COMING INTO BETTER AGREEMENT
WITH RESPECT TO THE HANDLING OF THE LOW PRESSURE SYSTEM POISED TO
AFFECT THE AREA THROUGH THIS TIME PERIOD. THE 00Z RUN OF THE NAM AND
GFS ARE FINALLY ALIGNING BETTER WITH THE MORE CONSISTENT
EC/GEM...ALTHOUGH THEY ARE A TOUCH FASTER AT SHIFTING THE LOW INTO
THE UPPER PENINSULA. AS OF 12Z/04 EACH OF THE MODELS ARE IN GOOD
AGREEMENT IN PLACING THE SURFACE LOW OVER SW WISCONSIN WITH VERY
SIMILAR INTENSITIES. THE UPPER LEVEL 500MB CLOSED LOW IS PROGGED TO
BE POSITIONED FARTHER NORTHWEST OVER NORTHWESTERN MN...INDICATING
THE POTENTIAL FOR ADDITIONAL INTENSIFICATION OF THE SURFACE LOW. AT
THAT TIME ISENTROPIC UPGLIDE IS EXPECTED TO CONTINUE AS SHOWN BY
ANALYZING MOISTURE AND MOISTURE TRANSPORT ON A 295K PRESSURE
ISOSURFACE. SOUNDINGS AROUND 12Z/04 INDICATE THAT MOST OF THE
PRECIPITATION EAST OF A MQT TO IMT LINE WILL LIKELY BE IN THE FORM
OF RAIN AS A FAIRLY DEEP WARM LAYER EXISTS IN THE BOUNDARY LAYER.
WEST OF THAT LINE ATMOSPHERIC PROFILES ARE SUCH THAT THE
PRECIPITATION SHOULD REMAIN IN THE FORM OF SNOW. ALSO AT THIS TIME
FORCING IN THE DGZ SEEMS FAIRLY LIMITED...HOWEVER...THIS WILL CHANGE
THROUGH THE DAY. THE LOW IS PROGGED TO BE OVER SOUTH CENTRAL WI BY
18Z/04. AS THIS LOW CONTINUES TO APPROACH DURING THIS TIME PERIOD
INCREASED MOISTURE AND FORCING IN THE DGZ IS EXPECTED TO INCREASE
ALLOWING FOR A STEADY INCREASE IN SNOWFALL INTENSITY DURING THE
AFTERNOON HOURS. BETWEEN 00Z/05 AND 06Z/05 THE LOW IS PROGGED TO
SHIFT NORTH AND EASTWARD INTO THE EAST CENTRAL PORTION OF THE UPPER
PENINSULA. INCREASED SNOWFALL RATES ARE EXPECTED TO CONTINUE DURING
THAT TIME PERIOD AS WELL...AS CONTINUED MOISTURE AND LIFT ARE
PROGGED TO BE COLLOCATED IN THE DGZ AS SHOWN BY ANALYZING 1000-500MB
RH AS WELL AS QCONV IN THE 700-500 DGZ LAYER AS IDENTIFIED USING
ATMOSPHERIC PROFILES OF THE EC/GEM. THE WESTERN HALF OF THE UPPER
PENINSULA LOOKS TO ALSO BE IN A FAVORED LOCATION FOR HEAVY SNOWFALL
AS THIS REGION IS IN THE FAVORED LEFT EXIT REGION OF AN UPPER LEVEL
JET. THE MAIN CAVEAT HERE IS THE NEW UNCERTAINTY WITH PRECIPITATION
TYPE WHICH WAS INTRODUCED BY THE 00Z EC/GEM/UKMET WHICH PULLS THE
SURFACE LOW MUCH FARTHER TO THE WEST...WHICH TAKES THE LOW VERY NEAR
WHERE THE PREVIOUS GFS MODELS WERE TAKING IT OVER THE PAST COUPLE OF
DAYS. THIS WOULD SHIFT THE RAIN SNOW LINE FARTHER WEST...POSSIBLY
REDUCING SNOWFALL TOTALS. HAVE DECIDED TO CONTINUE WITH AN UPDATED
SPS BASED ON COORDINATION WITH SURROUNDING OFFICES...AS CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO GO WITH A HEADLINE.
THURSDAY THROUGH SATURDAY...BETWEEN 12Z/05 AND 18Z/05 THE SURFACE
LOW IS PROGGED TO SHIFT NORTHEASTWARD TO JUST SOUTH OF JAMES
BAY...TAKEN THE BETTER SYNOPTIC FORCING OUT OF THE AREA. AT THE SAME
TIME A DEEP TROUGH DIGGING INTO THE NORTHERN PLAINS WILL BEGIN TO
INFLUENCE THE WEATHER IN THE UPPER PENINSULA. WINDS WILL BECOME
WESTERLY TO WEST NORTHWESTERLY IN THE RETURN FLOW ON THE BACK SIDE
OF THE LOW PRESSURE SYSTEM. THIS WILL ALLOW LAKE EFFECT SNOW DEVELOP
IN THE SNOWBELTS FAVORED WITH THE SAID WIND DIRECTION. 850MB
TEMPERATURES ARE EXPECTED TO DROP FROM NEAR -14C 12/05 TO AROUND
-22C 12Z/07. THESE TEMPERATURES ARE MORE THAN FAVORABLE FOR LES
GIVEN LAKE SURFACE TEMPERATURES AROUND 4C TO 5C...CREATING DELTA T
VALUES BETWEEN 18 AND 27 DEGREES THROUGH THIS TIME PERIOD.
WINDS...AGAIN...LOOK TO BE FAVORABLE WITH SURFACE TO 850MB WINDS
REMAINING OUT OF THE WEST...AND WELL WITHIN THE 30 DEGREE TOLERANCE
FOR LES. IT APPEARS AS IF THE TIME FRAME FOR HEAVIER LES WOULD OCCUR
THURSDAY EVENING INTO FRIDAY MORNING AS INVERSION HEIGHTS INCREASE
TO AROUND 8-9KFT AFTER ADJUSTING FOR LAKE SURFACE TEMPERATURES. THE
MOISTURE IS COLLOCATED WITH THE DGZ WHICH WOULD BE MORE FAVORABLE
FOR SNOWFLAKE PRODUCTION. FRIDAY AFTERNOON THROUGH SATURDAY
INVERSION HEIGHTS ARE EXPECTED TO BECOME MORE SHALLOW AS
TEMPERATURES ALSO BEGIN TO RAPIDLY DROP AS THE NEXT TROUGH AXIS
PRESSES INTO THE AREA. THESE COLDER TEMPERATURES WILL PRESS THE DGZ
DOWN TO THE VERY LOWEST LEVELS OF THE ATMOSPHERE. WHILE IT IS LIKELY
THAT SNOW WILL CONTINUE TO FALL THROUGH THE FRIDAY AFTERNOON INTO
SATURDAY TIME PERIOD...SNOW PRODUCTION WILL BE LIMITED AS THE
MOISTURE IS MAINLY OUTSIDE OF THE DGZ. TEMPERATURES THIS WEEKEND
WILL BE WELL BELOW NORMAL WITH TEMPERATURES DROPPING INTO THE TEENS
BELOW ZERO FRIDAY NIGHT INTO SATURDAY NIGHT...ESPECIALLY OVER THE
WEST HALF. HIGH TEMPERATURES WILLS STRUGGLE TO GET OUT OF THE SINGLE
DIGITS OVER WESTERN AREAS. WIND CHILLS THIS WEEKEND WILL BECOME
DANGEROUSLY COLD WITH READINGS DROPPING TO AROUND 30 BELOW ZERO OVER
THE INTERIOR WEST.
SATURDAY NIGHT THROUGH MONDAY...A SURFACE HIGH PRESSURE SYSTEM IS
PROGGED TO MOVE INTO THE UPPER GREAT LAKES REGION AS UPPER LEVEL
FLOW BECOMES SLIGHTLY MORE ZONAL SATURDAY NIGHT THROUGH SUNDAY. THIS
ALONG WITH DRYER AIR WILL ALLOW LAKE EFFECT SNOT TO DIMINISH. LOW
PRESSURE WILL THEN BUILD BACK INTO THE AREA SUNDAY NIGHT INTO
MONDAY. WINDS WILL BECOME SOUTH TO SOUTHWESTERLY DURING THIS TIME
PERIOD WHILE TEMPERATURES ALOFT AT 850MB LINGER AROUND -15C WHICH
WILL HELP LES TO DEVELOP OVER THE FAR EASTERN UPPER PENINSULA AS THE
WIND FLOW WOULD BE DIRECTLY ACROSS THE WARM WATERS OF LAKE MICHIGAN.
THE BEST CHANCE OF THIS HAPPENING WOULD BE SUNDAY NIGHT INTO MONDAY
MORNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 641 AM EST TUE DEC 3 2013
IWD...WITH A DOWNSLOPE E WIND AND WEAKENING BAND OF -SN...EXPECT
CONDITIONS TO IMPROVE TO VFR THIS MRNG AND AFTN. ANOTHER DISTURBANCE
APRCHG FM THE W TNGT MAY BRING A PERIOD OF SOME STEADIER -SN AND
MVFR TO PERHAPS IFR CONDITIONS.
CMX...EXPECT PREDOMINANT MVFR CONDITIONS TO DOMINATE THIS FCST
PERIOD WITH GUSTY UPSLOPE E WIND. ALTHOUGH THIS FLOW COULD BRING IFR
CONDITIONS...DRY UPSTREAM LLVL AIRMASS WILL LIMIT HOW FAR THE CIG
WILL DROP.
SAW...AS WEAKENING BAND OF -SN MOVES INTO THE AREA...EXPECT MVFR
CONDITIONS TO DVLP THIS MRNG WITH UPSLOPE E WIND. DRY NATURE OF THE
UPSTREAM LLVL AIRMASS WL LIMIT THE POTENTIAL FOR IFR CONDITIONS WITH
THIS UPSLOPE FLOW EVEN IF ANOTHER DISTURBANCE BRUSHES THE AREA WITH
SOME HEAVIER SN LATE THIS EVNG.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 AM EST TUE DEC 3 2013
EXPECT INCREASING E WINDS THRU TONIGHT AS THE PRES GRADIENT TIGHTENS
OVER THE UPPER LAKES BETWEEN HI PRES OVER NORTHERN ONTARIO AND LO
PRES TAKING SHAPE IN THE PLAINS. THE STRONGEST WINDS WILL BE OVER
WESTERN LAKE SUPERIOR...WHERE THE TERRAIN SURROUNDING THE LAKE
FUNNELS AND ENHANCES THE LARGER SCALE WINDS. MAINTAINED GOING GALE
WARNINGS FOR THE TWO WESTERN ZONES AND MENTIONED SOME GALE FORCE
GUSTS OVER THE CENTRAL AS WELL THIS AFTERNOON THRU TONIGHT.
LOW PRESSURE WILL MOVE ACROSS THE UPPER GREAT LAKES LATE WED THROUGH
THU MORNING. IN THE WAKE OF THE LOW...VERY COLD AIR ADVECTING OVER
THE RELATIVELY WARM WATERS WILL INCREASE INSTABILITY AND RESULT IN W
TO NW GALES AT TIMES FOR PORTIONS OF LAKE SUPERIOR WED NIGHT/THU.
CONTINUED FLOW OF VERY COLD AIR MAY RESULT IN A FEW GALE FORCE GUSTS
INTO SATURDAY BEFORE HIGH PRESSURE BUILDS IN SUNDAY. THIS HIGH
PRESSURE SYSTEM WILL MOVE DIRECTLY OVERHEAD BY SUNDAY AFTERNOON
ALLOW WINDS TO BECOME LIGHT AND VARIABLE. BUILDING WAVES AND THE
ARRIVAL OF THE ARCTIC AIR WILL CAUSE AN INCREASING FREEZING SPRAY
POTENTIAL FOR THE LAST HALF OF THE WORK WEEK AND INTO THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR MIZ009.
LAKE SUPERIOR...
GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 AM
EST /9 AM CST/ WEDNESDAY FOR LSZ162.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST WEDNESDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...KC
LONG TERM...KEC
AVIATION...KC
MARINE...KC/KEC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
711 AM EST TUE DEC 3 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 341 AM EST TUE DEC 3 2013
A WARM FRONT MOVING THROUGH LOWER MICHIGAN WILL BRING LIGHT SNOW
POSSIBLY MIXED WITH SLEET AND FREEZING RAIN THIS MORNING. WE DON/T
EXPECT MUCH IF ANY ACCUMULATION. HOWEVER A FEW ROADS COULD BECOME
SLICK. THE PCPN WILL BECOME LIGHT RAIN THIS AFTERNOON AS WARMER AIR
MOVES INTO THE REGION.
A STRONG COLD FRONT WILL MOVE THROUGH WEDNESDAY NIGHT BRINGING AN
ABRUPT END TO THE 50 DEGREE TEMPERATURES EXPECTED WEDNESDAY. SNOW
SHOWERS AND HIGHS IN THE 20S ARE EXPECTED FRIDAY THROUGH THE
WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
FORECAST CONCERNS DEAL WITH MIXED PCPN MAINLY THIS MORNING.
LATEST RADAR SHOWS A BAND OF PCPN STRETCHING FROM OCEANA COUNTY
SOUTHEAST TOWARD NW OHIO MOVING NEWD THROUGH THE CWA. MOST OF THIS
IS LIGHT SHOW BUT LOCAL OBS HAVE SHOWN SOME SLEET TOO. THIS WAS
CORROBORATED BY DUAL POL. LATEST HRRR AND FCST SOUNDINGS SUGGEST
SOME
LIGHT FREEZING RAIN IS POSSIBLE TOO THIS MORNING BEFORE TEMPS WARM
UP ENOUGH TO RESULT IN LIGHT RAIN. PCPN IS FAIRLY LIGHT AND ANY
ACCUMS SHOULD REMAIN LESS THAN AN INCH. THAT SAID...A FEW ROADS MAY
BECOME SLICK.
A WARM FRONT WILL CONTINUE TO PUSH NORTH THROUGH THE CWA TONIGHT. H8
TEMPS RISING TO 7C SHOULD RESULT IN SFC TEMPS IN THE 50S TOMORROW.
MODELS CONTINUE TO BE AT ODDS ON COLD FRONTAL TIMING. WE/LL BE
CONSISTENT THOUGH IN FOLLOWING THE SLOWER ECMWF DUE TO THE OCCLUDING
NATURE OF THE SYSTEM. THAT MEANS A FROPA WEDNESDAY NIGHT. HIGHS
THURSDAY WILL BE IN THE MID 30S. LIGHT SNOW SHOWERS POSSIBLE
THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
TWO MAIN HEADLINES OF THE LONG TERM REMAIN THE COLD AND LAKE EFFECT
SNOW SHOWERS. THE COLD MAY BE THE BIGGER STORY AS THE LAKE EFFECT
LOOKS TO BE SOMEWHAT MOISTURE DEPLETED.
COLD AIR ADVECTION WILL BE IN FULL SWING THURSDAY NIGHT AS WE BEGIN
THE LONG TERM WITH THE LOW MOVING AWAY ACROSS ONTARIO. DELTA T/S
WILL BE IN THE MIDDLE TEENS...PROVIDING DECENT INSTABILITY. MOISTURE
LOOKS LIMITED SO NOT EXPECTING ANYTHING IN THE WAY OF SIGNIFICANT
LAKE EFFECT. MINOR ACCUMULATIONS AT BEST.
THAT REALLY REMAINS THE CASE FOR FRIDAY THROUGH SATURDAY. CONTINUED
COLD AIR ADVECTION WILL PUSH DELTA T/S INTO THE LOWER 20S C...BUT
MOISTURE REMAINS A LIMITING FACTOR. WE NEVER DEEPLY PLUNGE INTO
CYCLONIC FLOW TO THE NORTH SIDE OF THE UPPER JET AXIS...INSTEAD
REMAINING IN A BROAD SOUTHWEST TO WEST FLOW. 1000-700MB RH VALUES
FROM FRIDAY THROUGH SATURDAY REMAIN IN THE 40-60 PCT RANGE WHICH IS
NOT IDEAL. 20-40 PCT CHANCES FOR SNOW SHOWERS THURSDAY NIGHT THROUGH
SATURDAY SEEM WARRANTED. AT THIS POINT NOT EXPECTING ANY BIG
ACCUMULATIONS...JUST PERSISTENT LIGHT SNOW SHOWERS.
LOW PRESSURE IS FORECAST BY THE ECMWF (STILL THE MODEL OF CHOICE
TONIGHT) TO SWING NORTH THROUGH THE AREA SUNDAY NIGHT INTO MONDAY
WHICH BRINGS A GENERAL LIGHT SYNOPTIC SNOW TO THE AREA.
LOWS IN THE TEENS THROUGH THE PERIOD WITH HIGHS IN THE 20S WILL BE
COMMON. THIS IS COLDER THAN NORMAL...BUT BY NO MEANS RARE FOR EARLY
DECEMBER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 711 AM EST TUE DEC 3 2013
AVIATION CONDITIONS SHOULD CONTINUE TO DETERIORATE THE NEXT 24
HOURS...WITH WIDESPREAD IFR EXPECTED THIS AFTERNOON. OVERNIGHT
MOST SITES SHOULD SEE CEILINGS DROP FURTHER...INTO LIFR.
A MIXTURE OF PRECIPITATION IS OCCURRING THIS MORNING AS WARMER AIR
SURGES INTO THE REGION ALOFT. SOME SNOW...SLEET AND FREEZING RAIN
MAY MIX IN FROM TIME TO TIME THROUGH 15Z OR SO. BY MIDDAY...ALL
PRECIPITATION SHOULD HAVE SWITCHED OVER TO RAIN. SCATTERED RAIN
SHOWERS WILL BE POSSIBLE THIS AFTERNOON AND EVENING.
CEILINGS SHOULD CONSISTENTLY LOWER THE NEXT 24 HOURS. FOG SHOULD
BECOME MORE PREVALENT WITH TIME...WITH IFR VISIBILITIES BECOMING
FAIRLY WIDESPREAD TONIGHT.
&&
.MARINE...
ISSUED AT 341 AM EST TUE DEC 3 2013
SOUTH TO SOUTHEAST WINDS WILL INCREASE TO 15 TO 25 KNOTS TODAY. THE
OFFSHORE NATURE OF THE WINDS SHOULD PRECLUDE WAVES FROM GETTING
HIGHER THAN 3 FEET.
&&
.HYDROLOGY...
ISSUED AT 341 AM EST TUE DEC 3 2013
NO HYDRO ISSUES TODAY. HOWEVER THE ARCTIC AIR EXPECTED BY THE END OF
THE WEEK COULD CAUSE ICE TO DEVELOP ON STREAMS AND RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
642 AM EST TUE DEC 3 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 447 AM EST TUE DEC 3 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RELATIVELY WEAK
ZONAL FLOW ALF OVER THE UPR GRT LKS TO THE N OF FASTER POLAR JET
OVER THE SRN 2/3 OF THE CONUS. THERE ARE 2 SHRTWVS OF NOTE EMBEDDED
IN THIS FLOW. THE FIRST IS MOVING E THRU MN AND CAUSING A BAND OF SN
EXTENDING FM NE MN SEWD OVER WRN LK SUP AND INTO CENTRAL WI AS OF
06Z UNDER AREA OF H85-5 QVECTOR CNVGC. THE AXIS OF HIER
REFLECTIVITIES IN WI APPEARS TO BE ORIENTED ALONG THE MOST
IMPRESSIVE ISENTROPIC ASCENT SHOWN ON THE 290K SFC /H7-75/...WHILE
THE MOST IMPRESSIVE RETURNS IN NE MN ALIGN WITH MOST VIGOROUS H85-5
QVECTOR CNVGC. THE 00Z INL/MPX RAOBS SHOW DEEP MSTR THRU THE DEPTH
OF THE TROP. ELY FEED OF DRIER LLVL AIR ASSOCIATED WITH AREA OF
MOCLR SKIES/HI PRES RDG AXIS STILL OVER FAR ERN UPR MI AND LOCATION
OF SHARPER H85 THERMAL PACKING/ISENTROPIC ASCENT TO THE S HAS SO FAR
LIMITED THE ENE EXTENT OF THE PCPN INTO UPR MI...BUT SN APPEARS
POISED TO SPREAD INTO THE WRN CWA PER LATEST SFC OBS/RADAR IMAGERY.
THE VSBY AT IWD FELL UNDER 2 MILES AT 07Z...AND THE VSBY AS CLOSE AS
ASHLAND IN NW WI IS DOWN TO 1/2 MILE. ENE FLOW DOWN WRN LK SUP MAY
BE ENHANCING THE SN INTO THIS AREA. IN THE AREA OVER WRN MN/MUCH OF
THE DAKOTAS UNDER DNVA/DEEP LYR QVECTOR DVGC BEHIND THE MN SHRTWV...
THERE IS LTL IF ANY PCPN FALLING EVEN THOUGH SKIES REMAIN CLDY WITH
QUITE A BIT OF MID LVL DRYING ABV LLVL MSTR SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. FARTHER TO THE W...THE 2ND MORE IMPRESSIVE
SHRTWV OF INTEREST IS MOVING EWD THRU THE NRN ROCKIES. 12HR H3 HGT
FALLS UP TO 200M AND H3 WIND SPEEDS UP TO 100M IN THE ACCOMPANYING
JET CORE ARE ASSOCIATED WITH THIS MORE IMPRESSIVE DISTURBANCE.
MAIN FCST CONCERNS IN THE SHORT TERM PERIOD ARE POPS/EXPECTED SN
ACCUMS THRU THIS MRNG ASSOCIATED WITH THE FIRST SHRTWV IN MN AND
NEED FOR ANY HEADLINES. FOCUS FOR TNGT TURNS TO POPS AND SN AMOUNTS
THAT WL ACCOMPANY THE APRCH OF THE 2ND STRONGER SHRTWV.
TODAY...AS MN SHRTWV TRACKS TO THE E INTO PERSISTENT SFC RDG AXIS
JUST TO THE E OF UPR MI AND AWAY FM TROF DEEPENING OVER THE W...
AREA OF H85-5 QVECTOR CNVGC IS PROGGED TO DIMINISH SGNFTLY BY 18Z
WITH MID LVL DRYING UNDER DVLPG H85-5 QVECTOR DVGC. EXPECT THE HIER
POPS THIS MRNG OVER THE W AND SCENTRAL UNDER THE SHARPER H85-5
QVECTOR CVNGC/SHARPER 295K ISENTROPIC ASCENT/AREA OF H85-7 FGEN.
GIVEN PRESENCE OF 2.5G/KG SPECIFIC HUMIDITY AT THIS LVL...EXPECT UP
TO 3 INCHES OF SN FOR THE 6-9 HR PERIOD OVER THE SW HALF OF THE CWA.
SINCE THE SN IS LIKELY TO FALL A FOR CLOSER TO 12Z HRS AT IWD...UP
TO 4 INCHES MAY ACCUMULATE THERE BEFORE THE PCPN DIMINISHES TOWARD
NOON. ALTHOUGH THE DGZ IS RATHER NARROW...MODELS SHOW FAIRLY
IMPRESSIVE OMEGA IN THIS LYR THAT MAY INCH SN/WATER RATIOS CLOSER
TO 15:1. CONSIDERING THE LO VSBYS REPORTED AT ASHLAND IN THE ABSENCE
OF LAKE ENHANCEMENT WITH THE LARGER SCALE E WIND...OPTED TO ISSUE A
WINTER WX ADVY FOR GOGEBIC COUNTY THRU MID MRNG. OTRW...UPSLOPE E
WIND OFF LK MI MAY CAUSE STEADIER SN TO LINGER LONGER OVER THE
SCENTRAL. SN WL LIKELY MOVE INTO THE E DURING THE AFTN BUT WL BE MUCH
LIGHTER AS THE DYNAMIC SUPPORT FADES AND HITS DRIER AIR.
TNGT...ALTHOUGH THE EARLY EVNG WL FEATURE DNVA/LARGER SCALE QVECTOR
DVGC LEFT IN THE WAKE OF THE DEPARTING/WEAKENING SHRTWV...FAVORED
CNDN MODEL SHOWS AXIS OF SHARPER H85-7 FGEN SUPPORTING BAND OF SN
NOW OVER SDAKOTA IMPACTING MAINLY THE SRN CWA FOR A COUPLE HRS IN
THE LATER EVNG. THE 00Z GFS/ECWMF SHOW A SIMILAR QPF...SO WENT FOR
HI END LIKELY POPS IN THIS AREA BY LATER IN THE EVNG. OVERALL MODEL
QPF UP TO 0.25 INCH WL SUPPORT A FEW INCHES OF SN IN THIS AREA. HIER
POPS/MORE SN MAY ARRIVE LATE OVER THE W AS THE DYNAMICS IN ADVANCE
OF THE SHRTWV MOVING THRU THE NRN ROCKIES PUSH TOWARD THE AREA. BUT
MODELS DISAGREE ON THE TIMING OF THE ARRIVAL OF THE DEEP LYR QVECTOR
CNVGC AS WELL AS INTENSITY OF THE SFC LO THAT MIGHT ACCOMPANY THE
LARGER SCALE FORCING. THE NAM/LOCAL WRF-ARW MODELS ARE THE MOST
AGGRESSIVE AT DEEPENING THE SFC LO AND BRINGING MORE PCPN FARTHER E.
BUT SINCE THE MAIN SHRTWV REMAINS SO FAR TO THE W THRU THE NGT...
SUSPECT THE SLOWER/WEAKER CNDN MODEL IS ON THE RIGHT TRACK. SO WENT
NO HIER THAN LIKELY POPS OVER THE FAR W FOR NOW. THE THERMAL FIELDS
FM THE CNDN MODEL INDICATE ENUF WARM AIR WL ARRIVE TO CAUSE THE SN
TO MIX WITH RA OVER THE FAR SCENTRAL.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EST TUE DEC 3 2013
CONTINUED CHALLENGING FORECAST IN STORE FOR WEDNESDAY THROUGH
WEDNESDAY NIGHT TIME FRAME AS A WINTER WEATHER SYSTEM TAKES AIM AT
THE UPPER GREAT LAKES. VERY COLD AIR IS EXPECTED TO BUILD IN ON THE
BACK SIDE OF THIS SYSTEM ALLOWING FOR VERY COLD TEMPERATURES FRIDAY
NIGHT THROUGH SATURDAY NIGHT.
WEDNESDAY INTO WEDNESDAY NIGHT...SITUATION LOOKS A BIT BETTER FROM A
FORECASTING STANDPOINT AS MODELS ARE COMING INTO BETTER AGREEMENT
WITH RESPECT TO THE HANDLING OF THE LOW PRESSURE SYSTEM POISED TO
AFFECT THE AREA THROUGH THIS TIME PERIOD. THE 00Z RUN OF THE NAM AND
GFS ARE FINALLY ALIGNING BETTER WITH THE MORE CONSISTENT
EC/GEM...ALTHOUGH THEY ARE A TOUCH FASTER AT SHIFTING THE LOW INTO
THE UPPER PENINSULA. AS OF 12Z/04 EACH OF THE MODELS ARE IN GOOD
AGREEMENT IN PLACING THE SURFACE LOW OVER SW WISCONSIN WITH VERY
SIMILAR INTENSITIES. THE UPPER LEVEL 500MB CLOSED LOW IS PROGGED TO
BE POSITIONED FARTHER NORTHWEST OVER NORTHWESTERN MN...INDICATING
THE POTENTIAL FOR ADDITIONAL INTENSIFICATION OF THE SURFACE LOW. AT
THAT TIME ISENTROPIC UPGLIDE IS EXPECTED TO CONTINUE AS SHOWN BY
ANALYZING MOISTURE AND MOISTURE TRANSPORT ON A 295K PRESSURE
ISOSURFACE. SOUNDINGS AROUND 12Z/04 INDICATE THAT MOST OF THE
PRECIPITATION EAST OF A MQT TO IMT LINE WILL LIKELY BE IN THE FORM
OF RAIN AS A FAIRLY DEEP WARM LAYER EXISTS IN THE BOUNDARY LAYER.
WEST OF THAT LINE ATMOSPHERIC PROFILES ARE SUCH THAT THE
PRECIPITATION SHOULD REMAIN IN THE FORM OF SNOW. ALSO AT THIS TIME
FORCING IN THE DGZ SEEMS FAIRLY LIMITED...HOWEVER...THIS WILL CHANGE
THROUGH THE DAY. THE LOW IS PROGGED TO BE OVER SOUTH CENTRAL WI BY
18Z/04. AS THIS LOW CONTINUES TO APPROACH DURING THIS TIME PERIOD
INCREASED MOISTURE AND FORCING IN THE DGZ IS EXPECTED TO INCREASE
ALLOWING FOR A STEADY INCREASE IN SNOWFALL INTENSITY DURING THE
AFTERNOON HOURS. BETWEEN 00Z/05 AND 06Z/05 THE LOW IS PROGGED TO
SHIFT NORTH AND EASTWARD INTO THE EAST CENTRAL PORTION OF THE UPPER
PENINSULA. INCREASED SNOWFALL RATES ARE EXPECTED TO CONTINUE DURING
THAT TIME PERIOD AS WELL...AS CONTINUED MOISTURE AND LIFT ARE
PROGGED TO BE COLLOCATED IN THE DGZ AS SHOWN BY ANALYZING 1000-500MB
RH AS WELL AS QCONV IN THE 700-500 DGZ LAYER AS IDENTIFIED USING
ATMOSPHERIC PROFILES OF THE EC/GEM. THE WESTERN HALF OF THE UPPER
PENINSULA LOOKS TO ALSO BE IN A FAVORED LOCATION FOR HEAVY SNOWFALL
AS THIS REGION IS IN THE FAVORED LEFT EXIT REGION OF AN UPPER LEVEL
JET. THE MAIN CAVEAT HERE IS THE NEW UNCERTAINTY WITH PRECIPITATION
TYPE WHICH WAS INTRODUCED BY THE 00Z EC/GEM/UKMET WHICH PULLS THE
SURFACE LOW MUCH FARTHER TO THE WEST...WHICH TAKES THE LOW VERY NEAR
WHERE THE PREVIOUS GFS MODELS WERE TAKING IT OVER THE PAST COUPLE OF
DAYS. THIS WOULD SHIFT THE RAIN SNOW LINE FARTHER WEST...POSSIBLY
REDUCING SNOWFALL TOTALS. HAVE DECIDED TO CONTINUE WITH AN UPDATED
SPS BASED ON COORDINATION WITH SURROUNDING OFFICES...AS CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO GO WITH A HEADLINE.
THURSDAY THROUGH SATURDAY...BETWEEN 12Z/05 AND 18Z/05 THE SURFACE
LOW IS PROGGED TO SHIFT NORTHEASTWARD TO JUST SOUTH OF JAMES
BAY...TAKEN THE BETTER SYNOPTIC FORCING OUT OF THE AREA. AT THE SAME
TIME A DEEP TROUGH DIGGING INTO THE NORTHERN PLAINS WILL BEGIN TO
INFLUENCE THE WEATHER IN THE UPPER PENINSULA. WINDS WILL BECOME
WESTERLY TO WEST NORTHWESTERLY IN THE RETURN FLOW ON THE BACK SIDE
OF THE LOW PRESSURE SYSTEM. THIS WILL ALLOW LAKE EFFECT SNOW DEVELOP
IN THE SNOWBELTS FAVORED WITH THE SAID WIND DIRECTION. 850MB
TEMPERATURES ARE EXPECTED TO DROP FROM NEAR -14C 12/05 TO AROUND
-22C 12Z/07. THESE TEMPERATURES ARE MORE THAN FAVORABLE FOR LES
GIVEN LAKE SURFACE TEMPERATURES AROUND 4C TO 5C...CREATING DELTA T
VALUES BETWEEN 18 AND 27 DEGREES THROUGH THIS TIME PERIOD.
WINDS...AGAIN...LOOK TO BE FAVORABLE WITH SURFACE TO 850MB WINDS
REMAINING OUT OF THE WEST...AND WELL WITHIN THE 30 DEGREE TOLERANCE
FOR LES. IT APPEARS AS IF THE TIME FRAME FOR HEAVIER LES WOULD OCCUR
THURSDAY EVENING INTO FRIDAY MORNING AS INVERSION HEIGHTS INCREASE
TO AROUND 8-9KFT AFTER ADJUSTING FOR LAKE SURFACE TEMPERATURES. THE
MOISTURE IS COLLOCATED WITH THE DGZ WHICH WOULD BE MORE FAVORABLE
FOR SNOWFLAKE PRODUCTION. FRIDAY AFTERNOON THROUGH SATURDAY
INVERSION HEIGHTS ARE EXPECTED TO BECOME MORE SHALLOW AS
TEMPERATURES ALSO BEGIN TO RAPIDLY DROP AS THE NEXT TROUGH AXIS
PRESSES INTO THE AREA. THESE COLDER TEMPERATURES WILL PRESS THE DGZ
DOWN TO THE VERY LOWEST LEVELS OF THE ATMOSPHERE. WHILE IT IS LIKELY
THAT SNOW WILL CONTINUE TO FALL THROUGH THE FRIDAY AFTERNOON INTO
SATURDAY TIME PERIOD...SNOW PRODUCTION WILL BE LIMITED AS THE
MOISTURE IS MAINLY OUTSIDE OF THE DGZ. TEMPERATURES THIS WEEKEND
WILL BE WELL BELOW NORMAL WITH TEMPERATURES DROPPING INTO THE TEENS
BELOW ZERO FRIDAY NIGHT INTO SATURDAY NIGHT...ESPECIALLY OVER THE
WEST HALF. HIGH TEMPERATURES WILLS STRUGGLE TO GET OUT OF THE SINGLE
DIGITS OVER WESTERN AREAS. WIND CHILLS THIS WEEKEND WILL BECOME
DANGEROUSLY COLD WITH READINGS DROPPING TO AROUND 30 BELOW ZERO OVER
THE INTERIOR WEST.
SATURDAY NIGHT THROUGH MONDAY...A SURFACE HIGH PRESSURE SYSTEM IS
PROGGED TO MOVE INTO THE UPPER GREAT LAKES REGION AS UPPER LEVEL
FLOW BECOMES SLIGHTLY MORE ZONAL SATURDAY NIGHT THROUGH SUNDAY. THIS
ALONG WITH DRYER AIR WILL ALLOW LAKE EFFECT SNOT TO DIMINISH. LOW
PRESSURE WILL THEN BUILD BACK INTO THE AREA SUNDAY NIGHT INTO
MONDAY. WINDS WILL BECOME SOUTH TO SOUTHWESTERLY DURING THIS TIME
PERIOD WHILE TEMPERATURES ALOFT AT 850MB LINGER AROUND -15C WHICH
WILL HELP LES TO DEVELOP OVER THE FAR EASTERN UPPER PENINSULA AS THE
WIND FLOW WOULD BE DIRECTLY ACROSS THE WARM WATERS OF LAKE MICHIGAN.
THE BEST CHANCE OF THIS HAPPENING WOULD BE SUNDAY NIGHT INTO MONDAY
MORNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 641 AM EST TUE DEC 3 2013
IWD...WITH A DOWNSLOPE E WIND AND WEAKENING BAND OF -SN...EXPECT
CONDITIONS TO IMPROVE TO VFR THIS MRNG AND AFTN. ANOTHER DISTURBANCE
APRCHG FM THE W TNGT MAY BRING A PERIOD OF SOME STEADIER -SN AND
MVFR TO PERHAPS IFR CONDITIONS.
CMX...EXPECT PREDOMINANT MVFR CONDITIONS TO DOMINATE THIS FCST
PERIOD WITH GUSTY UPSLOPE E WIND. ALTHOUGH THIS FLOW COULD BRING IFR
CONDITIONS...DRY UPSTREAM LLVL AIRMASS WILL LIMIT HOW FAR THE CIG
WILL DROP.
SAW...AS WEAKENING BAND OF -SN MOVES INTO THE AREA...EXPECT MVFR
CONDITIONS TO DVLP THIS MRNG WITH UPSLOPE E WIND. DRY NATURE OF THE
UPSTREAM LLVL AIRMASS WL LIMIT THE POTENTIAL FOR IFR CONDITIONS WITH
THIS UPSLOPE FLOW EVEN IF ANOTHER DISTURBANCE BRUSHES THE AREA WITH
SOME HEAVIER SN LATE THIS EVNG.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 AM EST TUE DEC 3 2013
EXPECT INCREASING E WINDS THRU TONIGHT AS THE PRES GRADIENT TIGHTENS
OVER THE UPPER LAKES BETWEEN HI PRES OVER NORTHERN ONTARIO AND LO
PRES TAKING SHAPE IN THE PLAINS. THE STRONGEST WINDS WILL BE OVER
WESTERN LAKE SUPERIOR...WHERE THE TERRAIN SURROUNDING THE LAKE
FUNNELS AND ENHANCES THE LARGER SCALE WINDS. MAINTAINED GOING GALE
WARNINGS FOR THE TWO WESTERN ZONES AND MENTIONED SOME GALE FORCE
GUSTS OVER THE CENTRAL AS WELL THIS AFTERNOON THRU TONIGHT.
LOW PRESSURE WILL MOVE ACROSS THE UPPER GREAT LAKES LATE WED THROUGH
THU MORNING. IN THE WAKE OF THE LOW...VERY COLD AIR ADVECTING OVER
THE RELATIVELY WARM WATERS WILL INCREASE INSTABILITY AND RESULT IN W
TO NW GALES AT TIMES FOR PORTIONS OF LAKE SUPERIOR WED NIGHT/THU.
CONTINUED FLOW OF VERY COLD AIR MAY RESULT IN A FEW GALE FORCE GUSTS
INTO SATURDAY BEFORE HIGH PRESSURE BUILDS IN SUNDAY. THIS HIGH
PRESSURE SYSTEM WILL MOVE DIRECTLY OVERHEAD BY SUNDAY AFTERNOON
ALLOW WINDS TO BECOME LIGHT AND VARIABLE. BUILDING WAVES AND THE
ARRIVAL OF THE ARCTIC AIR WILL CAUSE AN INCREASING FREEZING SPRAY
POTENTIAL FOR THE LAST HALF OF THE WORK WEEK AND INTO THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR MIZ009.
LAKE SUPERIOR...
GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 AM
EST /9 AM CST/ WEDNESDAY FOR LSZ162.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST WEDNESDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KEC
AVIATION...KC
MARINE...KC/KEC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
628 AM CST TUE DEC 3 2013
.UPDATE...
ISSUED AT 628 AM CST TUE DEC 3 2013
SENT ANOTHER UPDATE TO LOWER HIGH TEMPS AND HOURLY TEMPS FURTHER
FROM LEXINGTON-ORD IN COORDINATION WITH LBF.
UPDATE ISSUED AT 603 AM CST TUE DEC 3 2013
WITH THE INITIAL FCST ISSUANCE AT 4 AM...WAS UNSURE WHY THE
00Z/06Z NAM TEMPS WERE FCST TO BEHAVE THE WAY THEY WERE DEPICTED
AND NOW IT IS CLEAR AS WE SEE STRATUS SURGING S ACROSS CNTRL NEB.
THE SKY FCST HAS BEEN ENHANCED BY USING THE 13 KM RAP WHICH HAS AN
EXCELLENT HANDLE ON THE STRATUS...EVEN DEPICTING ITS LEADING EDGE
ERODING AROUND MIDDAY. HAVE ALSO REPLACED THE PREVIOUS HIGH TEMP
FCST BY A 50-50 BLEND THE 00Z/06Z NAM 2M TEMPS. THIS HAS COOLED
FCST HIGHS ALONG THE I-80 CORRIDOR NORTHWARD.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CST TUE DEC 3 2013
...AN EXTENDED PERIOD OF HARSH WINTER COLD IS ON THE DOORSTEP AND
ONCE IT ARRIVES TONIGHT THERE ARE NO SIGNS OF IT RELEASING UNTIL
MID-MONTH APPROACHES...
ALOFT: THE COLD CORE ARCTIC LOW THAT WAS OVER SIBERIA 7 DAYS AGO
IS NOW ON OUR DOORSTEP /CURRENTLY OVER MT/. WESTERLY FLOW WILL
BECOME SW AS THE LOW BECOMES ELONGATED AND OPENS UP...EJECTING A
SHORTWAVE TROF ACROSS THE NRN PLAINS THIS AFTERNOON AND TONIGHT.
SFC: THE ARCTIC COLD FRONT WAS ALONG THE SD-NEB BORDER...WITH A
PRE-FRONTAL TROF EXTENDING E-W ACROSS NEB. BOTH OF THESE FEATURES
TO PRESS S...CROSSING THE FCST AREA BETWEEN 2 PM AND 8 PM.
BITTERLY COLD HIGH PRES OVER THE CANADIAN ROCKIES BEGINS BUILDING
IN TONIGHT. A LEE-SIDE LOW WILL MIGRATE DOWN THE FRONT RANGE
TODAY AND THEN EJECT ACROSS OK TONIGHT. THIS WILL MAINTAIN A
TIGHT PRES GRADIENT.
HI-RES MESOSCALE MODELS SUGGEST THE FOLLOWING APPROXIMATE TIMES
OF FRONTAL PASSAGE:
3 PM ORD-LEXINGTON
4 PM OSCEOLA-KEARNEY-ELWOOD
5 PM YORK-FRANKLIN-LONG ISLAND KS
6 PM GENEVA-SMITH CENTER KS-PHILLIPSBURG KS
7 PM MANKATO-OSBORNE-STOCKTON
8 PM BELOIT
EARLY THIS MORNING: A BATCH OF MULTI-LAYERED MID-HIGH CLOUDS WAS
MOVING THRU THE FCST AREA. CLOUD TOPS WERE WARMING. UEX/LNX
RADARS HAVE SHOWN SOME SMALL POCKETS OF PRECIP...BUT SUB-CLOUD
AIR IS TOO DRY FOR ANYTHING TO SURVIVE TO THE SURFACE.
TODAY: ONCE THE BATCH OF CLOUDS DEPARTS TO THE E...WE COULD SEE A
PERIOD OF SUBSTANTIAL SUNSHINE. LOOK FOR A RAPID WARM-UP. THIS
WILL BE THE LAST DAY OF MUCH WARMER THAN NORMAL TEMPS. HIGHS ARE
PRIMARILY BASED ON THE 21Z/2 BIAS CORRECTED SREF.
THE SATELLITE FOG/REFLECTIVITY PRODUCT SHOWS STRATUS OVERCAST
IMMEDIATELY BEHIND T HE FRONT. IT IS DISCONCERTING TO SEE IT
DROPPING INTO NRN NEB. THIS WILL NEED TO BE MONITORED AS
SUBSTANTIAL CHANGES WILL NEED TO OCCUR TO THE SHORT-TERM FCST.
THE 06Z NAM SUGGESTS THE STRATUS WILL DROP INTO AREAS N OF HWY
92...BUT THEN GET ERODED BY BOUNDARY LAYER MIXING.
POSSIBLE FCST SHORT-COMINGS: DO WE HAVE THE TIMING OF FRONTAL
PASSAGE CORRECT? THIS WILL HAVE SIGNIFICANT IMPLICATIONS ON THE
FCST. CONFIDENCE IN HOURLY TEMPS AND HIGHS ARE BELOW AVERAGE FROM
HWY 6 NORTHWARD.
IMMEDIATELY BEHIND THE FRONT EXPECT A RAPID INCREASE IN N WINDS
AND IT WILL CONTINUE THRU TONIGHT.
WIND: COOPERATIVE INSTITUTE FOR PRECIP SYSTEMS /CIPS/ TOP 10
ANALOGS OFFER A 50-60% CHANCE OF 30-35 KT WINDS. THE CHANCE FOR
36-40 KTS IS 30-40%. THE 00Z NAM HAS 30 KTS AS LOW AS 1000 FT AT
ORD WITH A MAX OF 32-34 KTS AVAILABLE AT THE TOP OF THE MIXED
LAYER. OVER THE REST OF S-CNTRL NEB 30 KTS IS FCST AS LOW AS 1500
FT WITH 32 KTS MAX. OVER N-CNTRL KS 30 KTS WILL BE AVAILABLE AT
THE TOP OF THE MIXED LAYER /2000 FT/. THIS MATCHES WELL WITH WHAT
IS OFFERED FROM THE CIPS ANALOGS. SO EXPECT THE HIGHEST GUSTS N OF
I-80...BUT THERE IS POTENTIAL FOR EVERYWHERE TO GUST TO 30 KTS
WITH THE HIGHEST PROBABILITY OVER S-CNTRL NEB. 06Z NAM CHECKED. IT
LOOKS A BIT MORE THREATENING WITH MAX GUSTS UP TO 35 KTS N OF HWY
6.
TONIGHT: CLOUDY WITH HARSH N WINDS. LOW TEMPS NEAR NORMAL.
AS FOR PRECIP TODAY-TONIGHT...A SHALLOW FRONTOGENETIC CIRCULATION
WILL NOT BE AIDED BY ANY DEEP-LAYER FORCING/LIFT. AND WHILE THE
LOW-LEVELS AND MID-LEVELS ABOVE 12K FT WILL BE AT OR NEAR
SATURATION ...THE 7-11K FT LAYER WILL BE DRY. SO PLAYED IT AS A
SLIGHT CHANCE FOR A LITTLE LIGHT RAIN/SNOW N OF HWY 92 LATE THIS
AFTERNOON AND A SLIGHT CHANCE OF LIGHT SNOW TONIGHT. BY 09Z...THE
BASE OF THE STRATUS WILL BECOME COLD ENOUGH FOR ICE TO FORM IN-
CLOUD. SO A SLIGHT CHANCE OF FLURRIES WAS INCLUDED FROM HWY 92
DOWN TO HWY 6 LATE TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CST TUE DEC 3 2013
GUIDANCE SUGGESTS A MID TO UPPER LEVEL LONG WAVE TROUGH WILL
EXTEND FROM CENTRAL CANADA...SOUTHWEST INTO THE WESTERN CONUS AT
12Z WEDNESDAY. THIS LONG WAVE TROUGH IS EXPECTED TO PERSIST OVER
THE SAME AREAS THROUGH 12Z FRIDAY...AT WHICH TIME IT SHOULD MOVE
EAST/NORTHEAST AND WEAKEN. A SECOND MID TO UPPER LEVEL LONGWAVE
TROUGH IS THEN EXPECTED TO DEVELOP OVER THE WESTERN CONUS SATURDAY
INTO SATURDAY NIGHT AND PERSIST THROUGH THE END OF THE LONG TERM
FORECAST PERIOD. RESULTANT MID TO UPPER LEVEL FLOW OVER OUR AREA
IS EXPECTED TO REMAIN FROM THE SOUTHWEST 12Z WEDNESDAY THROUGH 12Z
FRIDAY...WITH QUASI-ZONAL FLOW EXPECTED FRIDAY INTO FRIDAY
NIGHT...AND SOUTHWEST FLOW ONCE AGAIN SATURDAY THROUGH THE END OF
THE LONG TERM FORECAST PERIOD. A CLOSED MID LEVEL LOW...EMBEDDED
WITHIN THE FIRST LONG WAVE TROUGH...IS EXPECTED OVER THE NORTHERN
PLAINS AT 12Z WEDNESDAY...WITH THIS MID LEVEL LOW EXPECTED TO
EJECT TO THE NORTHEAST...AWAY FROM THE LONG WAVE TROUGH...INTO
ONTARIO AND QUEBEC BETWEEN 12Z WEDNESDAY AND 12Z FRIDAY. A
SECONDARY MID LEVEL LOW IS ALSO EXPECTED TO MOVE SOUTH AND THEN
EAST FROM SASKATCHEWAN INTO THE NORTHERN PLAINS BETWEEN 12Z
WEDNESDAY AND 12Z FRIDAY. THIS SECONDARY MID LEVEL LOW IS THEN
EXPECTED TO MOVE EAST/NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY
AND ONTARIO...ALONG WITH THE LONG WAVE TROUGH...FRIDAY INTO FRIDAY
NIGHT. THERE ARE THEN INDICATIONS OF A MID LEVEL SHORTWAVE
EJECTING FROM THE WESTERN CONUS AND MOVING EAST ACROSS PORTIONS OF
THE CENTRAL AND SOUTHERN PLAINS ON SUNDAY. AT THE SURFACE AN AREA
LOW BAROMETRIC PRESSURE IS EXPECTED OVER THE UPPER MISSISSIPPI
VALLEY AT 12Z WEDNESDAY...WITH AN ASSOCIATED LOW LEVEL BAROCLINIC
ZONE EXTENDING SOUTH/SOUTHWEST FROM THE LOW INTO THE MID
MISSISSIPPI VALLEY AND SOUTHERN PLAINS. STRONG SURFACE RIDGING
SHOULD BE WORKING INTO THE CENTRAL PLAINS ON WEDNESDAY AS THE
FIRST MID LEVEL LOW AND SURFACE LOW DEPART TO THE NORTHEAST. THE
SURFACE RIDGE SHOULD THEN PERSIST ACROSS THE CENTRAL PLAINS
THROUGH FRIDAY AS THE SECONDARY MID LEVEL LOW ADVANCES SOUTH AND
THEN EAST FROM SASKATCHEWAN...INDUCING A WEAK AREA OF LOW
BAROMETRIC PRESSURE AT THE SURFACE ACROSS PORTIONS OF THE UPPER
MISSISSIPPI VALLEY. LEE SIDE TROUGHING ALONG THE FRONT RANGE IS
THEN EXPECTED TO DEVELOP FRIDAY NIGHT INTO SATURDAY.
FINALLY...THERE IS A LIKELIHOOD A SURFACE LOW WILL MOVE EAST
SOMEWHERE ACROSS THE CENTRAL AND/OR SOUTHERN PLAINS DURING THE DAY
SUNDAY AS THE MID LEVEL SHORTWAVE DOES THE SAME. GIVEN ALL
THIS...LOW LEVEL FLOW SHOULD REMAIN FROM THE NORTH/NORTHWEST
WEDNESDAY FRIDAY...WITH SOUTHERLY FLOW EXPECTED SATURDAY...AND
ANOTHER ROUND OF NORTHWESTERLY LOW LEVEL FLOW TOWARDS THE END OF
THE FORECAST PERIOD.
ALTHOUGH THERE COULD BE A WEAK RIBBON OF MID LEVEL THERMAL
ADVECTION GRAZING OUR NORTHWEST DURING THE DAY WEDNESDAY...AT THIS
TIME IT APPEARS ANY SUBSTANTIAL OMEGA WILL REMAIN RELEGATED
NORTH/NORTHEAST AND WEST OF OUR AREA...EITHER IN CLOSER PROXIMITY
TO THE DEPARTING MID LEVEL LOW TO OUR NORTH/NORTHEAST OR IN CLOSER
PROXIMITY TO THE LONGWAVE TROUGH AXIS TO OUR WEST. WENT AHEAD WITH
DRY CONDITIONS ON WEDNESDAY AS A RESULT. HEADING INTO WEDNESDAY
NIGHT...THERE ARE INDICATIONS OF A ~90KT MID LEVEL JET STREAK
MOVING INTO THE MID MISSISSIPPI VALLEY...WITH THE RIGHT-REAR
QUADRANT OF THIS STREAK PERHAPS GENERATING ENOUGH OF A DIRECT
THERMAL CIRCULATION AND RESULTANT OMEGA FOR PRECIPITATION
PRODUCTION ACROSS PORTIONS OF OUR CWA. QPF FIELDS FROM THE
NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL SEEM TO SUGGEST OUR
WEST/SOUTHWEST CWA STAND THE BEST CHANCE AT OBSERVING MEASURABLE
PRECIPITATION. AS A RESULT...WENT AHEAD WITH ~20% POPS ACROSS OUR
WEST/SOUTHWEST 00Z-06Z THURSDAY. IT APPEARS THE MID LEVEL JET
STREAK WILL PERSIST THURSDAY INTO THURSDAY NIGHT AS WELL...HOWEVER
IT ALSO APPEARS THE JET STREAK AXIS WILL SHIFT EAST/SOUTHEAST
SOMEWHAT...THUS POSITIONING THE RIGHT-REAR QUADRANT AND RESULTANT
OMEGA SLIGHTLY SOUTH/SOUTHEAST OF OUR AREA AS WELL. ALTHOUGH SOME
GUIDANCE SUGGESTS OUR EXTREME SOUTH COULD OBSERVE MEASURABLE
PRECIPITATION AT ONE TIME OR ANOTHER THURSDAY AND THURSDAY
NIGHT...THERE REALLY IS NO AGREEMENT BETWEEN THE MODELS AS TO
WHETHER THIS WILL OCCUR THURSDAY...THURSDAY NIGHT...OR AT ALL.
ALTHOUGH WE PROBABLY CANNOT COMPLETELY RULE OUT A PERIOD OF VERY
LIGHT PRECIPITATION AT SOME POINT DURING THE THURSDAY-THURSDAY
NIGHT TIME PERIOD...GIVEN THE PRIMARY AXIS OF OMEGA APPEARS TO
REMAIN SOUTH/SOUTHEAST OF OUR AREA AND THE VERY LOW CONFIDENCE
THAT ANYONE WOULD ACTUALLY OBSERVE MEASURABLE
PRECIPITATION...OPTED TO REMOVE MEASURABLE PRECIPITATION FROM THE
THURSDAY-THURSDAY NIGHT TIME PERIOD AND INSTEAD GO AHEAD WITH A
MENTION OF SNOW FLURRIES. THE APPROACH OF THE MID LEVEL SHORTWAVE
SUNDAY COULD THEN BRING A CHANCE FOR PRECIPITATION SUNDAY.
ALLBLEND RESPONDED BY PROVIDING ~30% POPS TO THE AREA AND THESE
POPS WERE LEFT UNCHANGED FOR THE MOST PART.
FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM
AND OPERATIONAL GFS...SUGGEST AN INVASION OF ARCTIC AIR WILL KEEP
THE LOWER TROPOSPHERE COLD ENOUGH FOR SNOW PRODUCTION DURING THE
LONG TERM FORECAST PERIOD. ANY SNOWFALL THAT IS REALIZED ACROSS
OUR CWA WEDNESDAY NIGHT INTO THURSDAY SHOULD REMAIN VERY LIGHT.
THAT BEING SAID...THE VERY COLD/DRY LOWER TROPOSPHERE SUGGESTS
SNOW-WATER RATIOS WILL BE VERY HIGH...SOMEWHERE IN 20-30:1
RANGE...THUS EVEN A COUPLE HUNDREDTHS OF AN INCH OF LIQUID
PRECIPITATION...WHICH IS FORECAST ACROSS OUR WEST/SOUTHWEST 00-06Z
THURSDAY...COULD BE CAPABLE OF PRODUCING ~0.5" OF SNOWFALL. THE
MID LEVEL SHORTWAVE WHICH COULD POTENTIALLY IMPACT OUR AREA NEXT
SUNDAY IS SLIGHTLY MORE INTERESTING...WITH THE OPERATIONAL GFS AND
EC BOTH SUGGESTING SNOWFALL ACCUMULATION IN EXCESS OF AN INCH WILL
BE REALIZED ACROSS THE CWA. CERTAINLY SOMETHING TO CONTINUE
MONITORING.
ARCTIC AIR REMAINS POISED TO OCCUPY THE CENTRAL PLAINS DURING THE
LONG TERM FORECAST PERIOD. TEMPERATURES WITHIN THE SOURCE REGION
OF THE ARCTIC AIRMASS...CURRENTLY ACROSS PORTIONS OF
ALBERTA...SASKATCHEWAN AND MANITOBA...ONLY CLIMBED INTO THE TEENS
AND 20S MONDAY AFTERNOON...AND THESE VALUES ARE ALSO BEING
PRESENTED TO OUR AREA BY MULTIPLE SETS OF GUIDANCE THURSDAY
ONWARD. WEDNESDAY MAY ACTUALLY BE A TOUCH WARMER AS THE TRUE MASS
OF ARCTIC AIR WILL TAKE SOME TIME TO WORK INTO THE REGION...THUS
WEDNESDAY AFTERNOON HIGHS RANGING FROM THE 20S TO NEAR 30 ARE
FORECAST. BASED ON THE SOURCE REGION OF THE INCOMING ARCTIC AIR
MASS...IT APPEARS LIKELY OVERNIGHT LOWS IN THE SINGLE DIGITS WILL
ALSO BE COMMON THURSDAY ONWARD.
FINALLY...LATEST GUIDANCE SUGGESTS A SUSTAINED LOW LEVEL WIND
FIELD AT AROUND 15KTS...WORKING IN CONCERT WITH THE AFOREMENTIONED
SINGLE DIGIT OVERNIGHT LOWS...WILL PROVIDE APPARENT TEMPERATURE
VALUES BETWEEN -15 AND -19 DEGREES F ACROSS NORTHWESTERN PORTIONS
OF OUR CWA WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. WILL GO
AHEAD AND OUTLOOK THESE CONDITIONS IN THE HWO...PRIMARILY FOR
LOCATIONS ALONG AND NORTHWEST OF A LINE OF LEXINGTON...TO LOUP
CITY AND GREELEY. ALTHOUGH THESE VALUES DO NOT JUSTIFY ADVISORY
ISSUANCE...THIS WILL CERTAINLY NEED TO BE MONITORED THROUGH THE
NEXT COUPLE DAYS IN CASE HEADLINES BECOME NECESSARY. ALTHOUGH NOT
AS WIDESPREAD...APPARENT TEMPERATURE VALUES ARE ALSO FORECAST TO
APPROACH -15 DEGREES F ACROSS VALLEY AND GREELEY COUNTIES EARLY
FRIDAY MORNING AS WELL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 603 AM CST TUE DEC 3 2013
TODAY: FOG/REFLECTIVITY SATELLITE IMAGERY SHOWS IFR STRATUS IS
SURGING S TOWARD GRI AT 12Z. ODX IS NOW OVC008 AND HAVE TIMED
THIS INTO GRI AT 14Z. THE STATISTICAL MODEL OUTPUT IS NOT HANDLING
THIS STRATUS. SO THIS FCST IS BASED ON CURRENT TRENDS AND MODEL RH
FIELDS...WHICH INDICATE THE LEADING EDGE OF THE STRATUS COULD
BEGIN ERODING AROUND MIDDAY...ALLOWING FOR A COUPLE HRS OF VFR
CIGS. IF THIS OCCURS...STRATUS WILL RE-INVADE AROUND 21Z WITH
FRONTAL PASSAGE. SHOULD SEE A SIGNIFICANT INCREASE IN N WINDS...
BUT THERE IS UNCERTAINTY ON IF ITS GRADUAL OR ABRUPT. CONFIDENCE:
AVERAGE
TONIGHT: STATISTICAL MODEL OUTPUT SUGGESTS MVFR CIGS...BUT CURRENT
OBS UPSTREAM ARE LARGELY IFR. THE TAF CIG IS MORE PESSIMISTIC THAN
MOS BUT NOT AS PESSIMISTIC AS CURRENT OBS UPSTREAM. BE AWARE THAT
CIGS MAY NEED TO BE DOWNGRADED A CATEGORY LATER TODAY. CONFIDENCE:
AVERAGE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
604 AM CST TUE DEC 3 2013
.UPDATE...
ISSUED AT 603 AM CST TUE DEC 3 2013
WITH THE INITIAL FCST ISSUANCE AT 4 AM...WAS UNSURE WHY THE
00Z/06Z NAM TEMPS WERE FCST TO BEHAVE THE WAY THEY WERE DEPICTED
AND NOW IT IS CLEAR AS WE SEE STRATUS SURGING S ACROSS CNTRL NEB.
THE SKY FCST HAS BEEN ENHANCED BY USING THE 13 KM RAP WHICH HAS AN
EXCELLENT HANDLE ON THE STRATUS...EVEN DEPICTING ITS LEADING EDGE
ERODING AROUND MIDDAY. HAVE ALSO REPLACED THE PREVIOUS HIGH TEMP
FCST BY A 50-50 BLEND THE 00Z/06Z NAM 2M TEMPS. THIS HAS COOLED
FCST HIGHS ALONG THE I-80 CORRIDOR NORTHWARD.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CST TUE DEC 3 2013
...AN EXTENDED PERIOD OF HARSH WINTER COLD IS ON THE DOORSTEP AND
ONCE IT ARRIVES TONIGHT THERE ARE NO SIGNS OF IT RELEASING UNTIL
MID-MONTH APPROACHES...
ALOFT: THE COLD CORE ARCTIC LOW THAT WAS OVER SIBERIA 7 DAYS AGO
IS NOW ON OUR DOORSTEP /CURRENTLY OVER MT/. WESTERLY FLOW WILL
BECOME SW AS THE LOW BECOMES ELONGATED AND OPENS UP...EJECTING A
SHORTWAVE TROF ACROSS THE NRN PLAINS THIS AFTERNOON AND TONIGHT.
SFC: THE ARCTIC COLD FRONT WAS ALONG THE SD-NEB BORDER...WITH A
PRE-FRONTAL TROF EXTENDING E-W ACROSS NEB. BOTH OF THESE FEATURES
TO PRESS S...CROSSING THE FCST AREA BETWEEN 2 PM AND 8 PM.
BITTERLY COLD HIGH PRES OVER THE CANADIAN ROCKIES BEGINS BUILDING
IN TONIGHT. A LEE-SIDE LOW WILL MIGRATE DOWN THE FRONT RANGE
TODAY AND THEN EJECT ACROSS OK TONIGHT. THIS WILL MAINTAIN A
TIGHT PRES GRADIENT.
HI-RES MESOSCALE MODELS SUGGEST THE FOLLOWING APPROXIMATE TIMES
OF FRONTAL PASSAGE:
3 PM ORD-LEXINGTON
4 PM OSCEOLA-KEARNEY-ELWOOD
5 PM YORK-FRANKLIN-LONG ISLAND KS
6 PM GENEVA-SMITH CENTER KS-PHILLIPSBURG KS
7 PM MANKATO-OSBORNE-STOCKTON
8 PM BELOIT
EARLY THIS MORNING: A BATCH OF MULTI-LAYERED MID-HIGH CLOUDS WAS
MOVING THRU THE FCST AREA. CLOUD TOPS WERE WARMING. UEX/LNX
RADARS HAVE SHOWN SOME SMALL POCKETS OF PRECIP...BUT SUB-CLOUD
AIR IS TOO DRY FOR ANYTHING TO SURVIVE TO THE SURFACE.
TODAY: ONCE THE BATCH OF CLOUDS DEPARTS TO THE E...WE COULD SEE A
PERIOD OF SUBSTANTIAL SUNSHINE. LOOK FOR A RAPID WARM-UP. THIS
WILL BE THE LAST DAY OF MUCH WARMER THAN NORMAL TEMPS. HIGHS ARE
PRIMARILY BASED ON THE 21Z/2 BIAS CORRECTED SREF.
THE SATELLITE FOG/REFLECTIVITY PRODUCT SHOWS STRATUS OVERCAST
IMMEDIATELY BEHIND T HE FRONT. IT IS DISCONCERTING TO SEE IT
DROPPING INTO NRN NEB. THIS WILL NEED TO BE MONITORED AS
SUBSTANTIAL CHANGES WILL NEED TO OCCUR TO THE SHORT-TERM FCST.
THE 06Z NAM SUGGESTS THE STRATUS WILL DROP INTO AREAS N OF HWY
92...BUT THEN GET ERODED BY BOUNDARY LAYER MIXING.
POSSIBLE FCST SHORT-COMINGS: DO WE HAVE THE TIMING OF FRONTAL
PASSAGE CORRECT? THIS WILL HAVE SIGNIFICANT IMPLICATIONS ON THE
FCST. CONFIDENCE IN HOURLY TEMPS AND HIGHS ARE BELOW AVERAGE FROM
HWY 6 NORTHWARD.
IMMEDIATELY BEHIND THE FRONT EXPECT A RAPID INCREASE IN N WINDS
AND IT WILL CONTINUE THRU TONIGHT.
WIND: COOPERATIVE INSTITUTE FOR PRECIP SYSTEMS /CIPS/ TOP 10
ANALOGS OFFER A 50-60% CHANCE OF 30-35 KT WINDS. THE CHANCE FOR
36-40 KTS IS 30-40%. THE 00Z NAM HAS 30 KTS AS LOW AS 1000 FT AT
ORD WITH A MAX OF 32-34 KTS AVAILABLE AT THE TOP OF THE MIXED
LAYER. OVER THE REST OF S-CNTRL NEB 30 KTS IS FCST AS LOW AS 1500
FT WITH 32 KTS MAX. OVER N-CNTRL KS 30 KTS WILL BE AVAILABLE AT
THE TOP OF THE MIXED LAYER /2000 FT/. THIS MATCHES WELL WITH WHAT
IS OFFERED FROM THE CIPS ANALOGS. SO EXPECT THE HIGHEST GUSTS N OF
I-80...BUT THERE IS POTENTIAL FOR EVERYWHERE TO GUST TO 30 KTS
WITH THE HIGHEST PROBABILITY OVER S-CNTRL NEB. 06Z NAM CHECKED. IT
LOOKS A BIT MORE THREATENING WITH MAX GUSTS UP TO 35 KTS N OF HWY
6.
TONIGHT: CLOUDY WITH HARSH N WINDS. LOW TEMPS NEAR NORMAL.
AS FOR PRECIP TODAY-TONIGHT...A SHALLOW FRONTOGENETIC CIRCULATION
WILL NOT BE AIDED BY ANY DEEP-LAYER FORCING/LIFT. AND WHILE THE
LOW-LEVELS AND MID-LEVELS ABOVE 12K FT WILL BE AT OR NEAR
SATURATION ...THE 7-11K FT LAYER WILL BE DRY. SO PLAYED IT AS A
SLIGHT CHANCE FOR A LITTLE LIGHT RAIN/SNOW N OF HWY 92 LATE THIS
AFTERNOON AND A SLIGHT CHANCE OF LIGHT SNOW TONIGHT. BY 09Z...THE
BASE OF THE STRATUS WILL BECOME COLD ENOUGH FOR ICE TO FORM IN-
CLOUD. SO A SLIGHT CHANCE OF FLURRIES WAS INCLUDED FROM HWY 92
DOWN TO HWY 6 LATE TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CST TUE DEC 3 2013
GUIDANCE SUGGESTS A MID TO UPPER LEVEL LONG WAVE TROUGH WILL
EXTEND FROM CENTRAL CANADA...SOUTHWEST INTO THE WESTERN CONUS AT
12Z WEDNESDAY. THIS LONG WAVE TROUGH IS EXPECTED TO PERSIST OVER
THE SAME AREAS THROUGH 12Z FRIDAY...AT WHICH TIME IT SHOULD MOVE
EAST/NORTHEAST AND WEAKEN. A SECOND MID TO UPPER LEVEL LONGWAVE
TROUGH IS THEN EXPECTED TO DEVELOP OVER THE WESTERN CONUS SATURDAY
INTO SATURDAY NIGHT AND PERSIST THROUGH THE END OF THE LONG TERM
FORECAST PERIOD. RESULTANT MID TO UPPER LEVEL FLOW OVER OUR AREA
IS EXPECTED TO REMAIN FROM THE SOUTHWEST 12Z WEDNESDAY THROUGH 12Z
FRIDAY...WITH QUASI-ZONAL FLOW EXPECTED FRIDAY INTO FRIDAY
NIGHT...AND SOUTHWEST FLOW ONCE AGAIN SATURDAY THROUGH THE END OF
THE LONG TERM FORECAST PERIOD. A CLOSED MID LEVEL LOW...EMBEDDED
WITHIN THE FIRST LONG WAVE TROUGH...IS EXPECTED OVER THE NORTHERN
PLAINS AT 12Z WEDNESDAY...WITH THIS MID LEVEL LOW EXPECTED TO
EJECT TO THE NORTHEAST...AWAY FROM THE LONG WAVE TROUGH...INTO
ONTARIO AND QUEBEC BETWEEN 12Z WEDNESDAY AND 12Z FRIDAY. A
SECONDARY MID LEVEL LOW IS ALSO EXPECTED TO MOVE SOUTH AND THEN
EAST FROM SASKATCHEWAN INTO THE NORTHERN PLAINS BETWEEN 12Z
WEDNESDAY AND 12Z FRIDAY. THIS SECONDARY MID LEVEL LOW IS THEN
EXPECTED TO MOVE EAST/NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY
AND ONTARIO...ALONG WITH THE LONG WAVE TROUGH...FRIDAY INTO FRIDAY
NIGHT. THERE ARE THEN INDICATIONS OF A MID LEVEL SHORTWAVE
EJECTING FROM THE WESTERN CONUS AND MOVING EAST ACROSS PORTIONS OF
THE CENTRAL AND SOUTHERN PLAINS ON SUNDAY. AT THE SURFACE AN AREA
LOW BAROMETRIC PRESSURE IS EXPECTED OVER THE UPPER MISSISSIPPI
VALLEY AT 12Z WEDNESDAY...WITH AN ASSOCIATED LOW LEVEL BAROCLINIC
ZONE EXTENDING SOUTH/SOUTHWEST FROM THE LOW INTO THE MID
MISSISSIPPI VALLEY AND SOUTHERN PLAINS. STRONG SURFACE RIDGING
SHOULD BE WORKING INTO THE CENTRAL PLAINS ON WEDNESDAY AS THE
FIRST MID LEVEL LOW AND SURFACE LOW DEPART TO THE NORTHEAST. THE
SURFACE RIDGE SHOULD THEN PERSIST ACROSS THE CENTRAL PLAINS
THROUGH FRIDAY AS THE SECONDARY MID LEVEL LOW ADVANCES SOUTH AND
THEN EAST FROM SASKATCHEWAN...INDUCING A WEAK AREA OF LOW
BAROMETRIC PRESSURE AT THE SURFACE ACROSS PORTIONS OF THE UPPER
MISSISSIPPI VALLEY. LEE SIDE TROUGHING ALONG THE FRONT RANGE IS
THEN EXPECTED TO DEVELOP FRIDAY NIGHT INTO SATURDAY.
FINALLY...THERE IS A LIKELIHOOD A SURFACE LOW WILL MOVE EAST
SOMEWHERE ACROSS THE CENTRAL AND/OR SOUTHERN PLAINS DURING THE DAY
SUNDAY AS THE MID LEVEL SHORTWAVE DOES THE SAME. GIVEN ALL
THIS...LOW LEVEL FLOW SHOULD REMAIN FROM THE NORTH/NORTHWEST
WEDNESDAY FRIDAY...WITH SOUTHERLY FLOW EXPECTED SATURDAY...AND
ANOTHER ROUND OF NORTHWESTERLY LOW LEVEL FLOW TOWARDS THE END OF
THE FORECAST PERIOD.
ALTHOUGH THERE COULD BE A WEAK RIBBON OF MID LEVEL THERMAL
ADVECTION GRAZING OUR NORTHWEST DURING THE DAY WEDNESDAY...AT THIS
TIME IT APPEARS ANY SUBSTANTIAL OMEGA WILL REMAIN RELEGATED
NORTH/NORTHEAST AND WEST OF OUR AREA...EITHER IN CLOSER PROXIMITY
TO THE DEPARTING MID LEVEL LOW TO OUR NORTH/NORTHEAST OR IN CLOSER
PROXIMITY TO THE LONGWAVE TROUGH AXIS TO OUR WEST. WENT AHEAD WITH
DRY CONDITIONS ON WEDNESDAY AS A RESULT. HEADING INTO WEDNESDAY
NIGHT...THERE ARE INDICATIONS OF A ~90KT MID LEVEL JET STREAK
MOVING INTO THE MID MISSISSIPPI VALLEY...WITH THE RIGHT-REAR
QUADRANT OF THIS STREAK PERHAPS GENERATING ENOUGH OF A DIRECT
THERMAL CIRCULATION AND RESULTANT OMEGA FOR PRECIPITATION
PRODUCTION ACROSS PORTIONS OF OUR CWA. QPF FIELDS FROM THE
NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL SEEM TO SUGGEST OUR
WEST/SOUTHWEST CWA STAND THE BEST CHANCE AT OBSERVING MEASURABLE
PRECIPITATION. AS A RESULT...WENT AHEAD WITH ~20% POPS ACROSS OUR
WEST/SOUTHWEST 00Z-06Z THURSDAY. IT APPEARS THE MID LEVEL JET
STREAK WILL PERSIST THURSDAY INTO THURSDAY NIGHT AS WELL...HOWEVER
IT ALSO APPEARS THE JET STREAK AXIS WILL SHIFT EAST/SOUTHEAST
SOMEWHAT...THUS POSITIONING THE RIGHT-REAR QUADRANT AND RESULTANT
OMEGA SLIGHTLY SOUTH/SOUTHEAST OF OUR AREA AS WELL. ALTHOUGH SOME
GUIDANCE SUGGESTS OUR EXTREME SOUTH COULD OBSERVE MEASURABLE
PRECIPITATION AT ONE TIME OR ANOTHER THURSDAY AND THURSDAY
NIGHT...THERE REALLY IS NO AGREEMENT BETWEEN THE MODELS AS TO
WHETHER THIS WILL OCCUR THURSDAY...THURSDAY NIGHT...OR AT ALL.
ALTHOUGH WE PROBABLY CANNOT COMPLETELY RULE OUT A PERIOD OF VERY
LIGHT PRECIPITATION AT SOME POINT DURING THE THURSDAY-THURSDAY
NIGHT TIME PERIOD...GIVEN THE PRIMARY AXIS OF OMEGA APPEARS TO
REMAIN SOUTH/SOUTHEAST OF OUR AREA AND THE VERY LOW CONFIDENCE
THAT ANYONE WOULD ACTUALLY OBSERVE MEASURABLE
PRECIPITATION...OPTED TO REMOVE MEASURABLE PRECIPITATION FROM THE
THURSDAY-THURSDAY NIGHT TIME PERIOD AND INSTEAD GO AHEAD WITH A
MENTION OF SNOW FLURRIES. THE APPROACH OF THE MID LEVEL SHORTWAVE
SUNDAY COULD THEN BRING A CHANCE FOR PRECIPITATION SUNDAY.
ALLBLEND RESPONDED BY PROVIDING ~30% POPS TO THE AREA AND THESE
POPS WERE LEFT UNCHANGED FOR THE MOST PART.
FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM
AND OPERATIONAL GFS...SUGGEST AN INVASION OF ARCTIC AIR WILL KEEP
THE LOWER TROPOSPHERE COLD ENOUGH FOR SNOW PRODUCTION DURING THE
LONG TERM FORECAST PERIOD. ANY SNOWFALL THAT IS REALIZED ACROSS
OUR CWA WEDNESDAY NIGHT INTO THURSDAY SHOULD REMAIN VERY LIGHT.
THAT BEING SAID...THE VERY COLD/DRY LOWER TROPOSPHERE SUGGESTS
SNOW-WATER RATIOS WILL BE VERY HIGH...SOMEWHERE IN 20-30:1
RANGE...THUS EVEN A COUPLE HUNDREDTHS OF AN INCH OF LIQUID
PRECIPITATION...WHICH IS FORECAST ACROSS OUR WEST/SOUTHWEST 00-06Z
THURSDAY...COULD BE CAPABLE OF PRODUCING ~0.5" OF SNOWFALL. THE
MID LEVEL SHORTWAVE WHICH COULD POTENTIALLY IMPACT OUR AREA NEXT
SUNDAY IS SLIGHTLY MORE INTERESTING...WITH THE OPERATIONAL GFS AND
EC BOTH SUGGESTING SNOWFALL ACCUMULATION IN EXCESS OF AN INCH WILL
BE REALIZED ACROSS THE CWA. CERTAINLY SOMETHING TO CONTINUE
MONITORING.
ARCTIC AIR REMAINS POISED TO OCCUPY THE CENTRAL PLAINS DURING THE
LONG TERM FORECAST PERIOD. TEMPERATURES WITHIN THE SOURCE REGION
OF THE ARCTIC AIRMASS...CURRENTLY ACROSS PORTIONS OF
ALBERTA...SASKATCHEWAN AND MANITOBA...ONLY CLIMBED INTO THE TEENS
AND 20S MONDAY AFTERNOON...AND THESE VALUES ARE ALSO BEING
PRESENTED TO OUR AREA BY MULTIPLE SETS OF GUIDANCE THURSDAY
ONWARD. WEDNESDAY MAY ACTUALLY BE A TOUCH WARMER AS THE TRUE MASS
OF ARCTIC AIR WILL TAKE SOME TIME TO WORK INTO THE REGION...THUS
WEDNESDAY AFTERNOON HIGHS RANGING FROM THE 20S TO NEAR 30 ARE
FORECAST. BASED ON THE SOURCE REGION OF THE INCOMING ARCTIC AIR
MASS...IT APPEARS LIKELY OVERNIGHT LOWS IN THE SINGLE DIGITS WILL
ALSO BE COMMON THURSDAY ONWARD.
FINALLY...LATEST GUIDANCE SUGGESTS A SUSTAINED LOW LEVEL WIND
FIELD AT AROUND 15KTS...WORKING IN CONCERT WITH THE AFOREMENTIONED
SINGLE DIGIT OVERNIGHT LOWS...WILL PROVIDE APPARENT TEMPERATURE
VALUES BETWEEN -15 AND -19 DEGREES F ACROSS NORTHWESTERN PORTIONS
OF OUR CWA WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. WILL GO
AHEAD AND OUTLOOK THESE CONDITIONS IN THE HWO...PRIMARILY FOR
LOCATIONS ALONG AND NORTHWEST OF A LINE OF LEXINGTON...TO LOUP
CITY AND GREELEY. ALTHOUGH THESE VALUES DO NOT JUSTIFY ADVISORY
ISSUANCE...THIS WILL CERTAINLY NEED TO BE MONITORED THROUGH THE
NEXT COUPLE DAYS IN CASE HEADLINES BECOME NECESSARY. ALTHOUGH NOT
AS WIDESPREAD...APPARENT TEMPERATURE VALUES ARE ALSO FORECAST TO
APPROACH -15 DEGREES F ACROSS VALLEY AND GREELEY COUNTIES EARLY
FRIDAY MORNING AS WELL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 603 AM CST TUE DEC 3 2013
TODAY: FOG/REFLECTIVITY SATELLITE IMAGERY SHOWS IFR STRATUS IS
SURGING S TOWARD GRI AT 12Z. ODX IS NOW OVC008 AND HAVE TIMED
THIS INTO GRI AT 14Z. THE STATISTICAL MODEL OUTPUT IS NOT HANDLING
THIS STRATUS. SO THIS FCST IS BASED ON CURRENT TRENDS AND MODEL RH
FIELDS...WHICH INDICATE THE LEADING EDGE OF THE STRATUS COULD
BEGIN ERODING AROUND MIDDAY...ALLOWING FOR A COUPLE HRS OF VFR
CIGS. IF THIS OCCURS...STRATUS WILL RE-INVADE AROUND 21Z WITH
FRONTAL PASSAGE. SHOULD SEE A SIGNIFICANT INCREASE IN N WINDS...
BUT THERE IS UNCERTAINTY ON IF ITS GRADUAL OR ABRUPT. CONFIDENCE:
AVERAGE
TONIGHT: STATISTICAL MODEL OUTPUT SUGGESTS MVFR CIGS...BUT CURRENT
OBS UPSTREAM ARE LARGELY IFR. THE TAF CIG IS MORE PESSIMISTIC THAN
MOS BUT NOT AS PESSIMISTIC AS CURRENT OBS UPSTREAM. BE AWARE THAT
CIGS MAY NEED TO BE DOWNGRADED A CATEGORY LATER TODAY. CONFIDENCE:
AVERAGE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
706 AM EST TUE DEC 3 2013
.SYNOPSIS...COASTAL LOW PRESSURE WILL MOVE NORTHEAST AWAY FROM NORTH
CAROLINA THIS MORNING. WEAK HIGH PRESSURE WILL BUILD OVER THE AREA
TODAY AND TONIGHT...THEN SHIFT OFFSHORE WEDNESDAY AS A WARM FRONT
APPROACHES FROM THE SOUTH.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 235 AM TUESDAY...
TODAY WILL MARK THE START OF A PERIOD OF VERY LITTLE SUNSHINE. THE
LATEST SURFACE ANALYSIS SHOWS THE LOW OFF THE NRN NC OUTER BANKS
(ALONG THE OLD FRONT) HEADING ENE AWAY FROM OUR AREA (PUSHED BY THE
BAGGY MID LEVEL TROUGH NOW CROSSING THE AREA)... WHILE WEAK NARROW
HIGH PRESSURE SLIDES IN FROM THE WEST. THIS SURFACE RIDGE WILL BE
PROGRESSIVE... MOVING TO OUR EAST THIS AFTERNOON AS A LOW LEVEL WARM
FRONTAL ZONE (NOW STRETCHING ACROSS E TN THROUGH GA) HEADS SLOWLY NE
TOWARD CENTRAL NC. PATCHY LIGHT RAIN OVER AL/GA (FUELED IN PART BY
LOW LEVEL MOIST UPGLIDE AND WEAK MID LEVEL DPVA) IS MOVING EASTWARD
INTO SC AND SW NC... AND THE LATEST HRRR RUNS BRING THIS INTO OUR
FAR SW CWA EARLY THIS MORNING BEFORE IT DISSIPATES... SUPPORTING THE
IDEA THAT IT WILL ENCOUNTER ENOUGH LOW LEVEL DRY AIR IN PLACE TO BE
OF LITTLE CONSEQUENCE. WILL RETAIN A LOW CHANCE OF A SPRINKLE IN THE
SW THROUGH JUST PAST DAYBREAK. LOW LEVEL MOISTURE SHOULD CONTINUE TO
INCREASE FROM SW TO NE ACROSS CENTRAL NC THROUGH TODAY... WITH NE
SECTIONS SEEING THE MOST SUNSHINE (ALTHOUGH THIS TOO SHOULD BE
FILTERED) AND THE WEST SEEING VERY LITTLE SUN AS THE LOW LEVEL MOIST
UPGLIDE AT 290-300K RAMPS UP AND DEEPENS EARLY. MODELS DEPICT A VERY
WEAK MID LEVEL WAVE TRACKING FROM THE CENTRAL PLAINS THROUGH THE
MIDATLANTIC AREA TONIGHT... AND THE INCREASING MOISTURE COMBINED
WITH THIS WEAK LIFT ALOFT AND ALSO-WEAK LOWER-LEVEL LIFT WITH THE
APPROACHING WARM FRONT (EXPECTED TO PUSH THROUGH SC TOWARD THE NC
BORDER BY MIDNIGHT AND INTO FAR SRN AND SE NC OVERNIGHT) INCLUDING
WEAK 850 MB MASS CONVERGENCE WARRANTS A CHANCE OF LIGHT RAIN OVER
THE WRN AND EXTREME SRN CWA STARTING LATE THIS AFTERNOON GOING INTO
THIS EVENING. EXPECT LOW CHANCES TO THEN SPREAD NORTHWARD THROUGH NC
OVERNIGHT... BUT THE ANTECEDENT DRIER AIR HERE AND WEAK NATURE OF
THE ASCENT SHOULD GREATLY LIMIT COVERAGE AND AMOUNTS FARTHER NORTH.
THIS POP SCENARIO IS SUPPORTED BY THE SREF AND LATEST HI-RES WRF
RUNS. THE COOLEST TEMPS ACROSS THE AREA TODAY SHOULD BE IN THE SW
WHERE CLOUDS WILL BE THICKEST AND MOST PERSISTENT. THICKNESSES STILL
A BIT BELOW NORMAL FAVOR BELOW-NORMAL HIGHS OF 57-62. MILD LOWS OF
43-50... INCLUDING A SMALL UPWARD BUMP IN THE SOUTHERN CWA WITH
THICK CLOUDS AND THE NEARING WARM FRONT. -GIH
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 305 AM TUESDAY...
THE LOW LEVEL WARM FRONT IS EXPECTED TO CONTINUE ITS SLOW NORTHWARD
PROGRESSION THROUGH NC... ALTHOUGH THE MODELS SUGGEST THAT WHILE THE
925-850 MB FRONT SHOULD PROGRESS TO OUR NORTH... THE SURFACE WARM
FRONTAL ZONE MAY NOT QUITE GET ALL OF THE WAY THROUGH OUR CWA AS A
POCKET OF WEAKLY STABLE AIR MAY LINGER OVER THE NW PIEDMONT. WITHIN
THE DEEP SW FLOW... HIGH PW AIR WILL CONTINUE TO FUNNEL INTO
CENTRAL/ERN NC WITH VALUES AT OR OVER 1 INCH... NEAR OR EXCEEDING
200% OF NORMAL... WITH STEADY MOIST ISENTROPIC UPGLIDE OVER THE
AREA... PARTICULARLY WED MORNING... DECREASING AS THE WARM FRONT
JUST ALOFT SHIFTS TO OUR NORTH WITH UPGLIDE BECOMING WEAKER AND MORE
SHALLOW. THE EARLIER FORECAST SHOWS THIS TREND FAIRLY WELL... WITH
SLIGHT CHANCE POPS AND LOWER AMOUNTS IN THE NW WITH CHANCE POPS AND
A BIT MORE OVER THE SE CWA. WITH DECENT AGREEMENT ON THIS PATTERN
AMONGST THE MOST RECENT MODELS RUNS... WILL RETAIN THIS
CONFIGURATION... FOCUSING THE HIGHER (BUT STILL LESS THAN A 40%
CHANCE) POPS IN THE SE IN THE MORNING BEFORE TAPERING THEM OFF IN
THE AFTERNOON WITH THE DEPARTURE OF THE BETTER (YET STILL MODEST)
FORCING FOR ASCENT AND A BRIEF DIP IN THE PRECIP WATER. THE FLAT
FLOW ALOFT THAT IS GENTLY ANTICYCLONIC AND THE FOCUS OF THE WEAK
FORCING CONFINED TO THE LOWER ALTITUDES WILL LIMIT OVERALL PRECIP
TOTALS. EXPECT IT TO REMAIN MOSTLY CLOUDY TO CLOUDY... ESPECIALLY
OVERNIGHT AS ANOTHER SURGE IN VERY HIGH PW SPREADS IN FROM THE SW.
HIGHS FROM NEAR 60 NW (WHERE THE SLIGHTLY COOLER AND MORE STABLE AIR
WILL HOLD ON LONGER INTO WED) TO AROUND 70 SE (THANKS TO THICKNESSES
CLIMBING WELL ABOVE NORMAL). MILD LOWS 53-58. -GIH
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 250 AM MONDAY...
AN AMPLIFIED LONGWAVE PATTERN IN THE MEDIUM RANGE WILL FEATURE A
TROUGH OVER THE WESTERN US AND A RIDGE OVER THE WESTERN
ATLANTIC...WHICH WILL LEAD TO SPEEDY SOUTHWESTERLY FLOW ALOFT
BETWEEN THE TWO AND ACTIVE WESTERN OVER THE EASTERN US. AHEAD OF A
SLOWLY EVOLVING COLD FRONT OVER THE MIDWEST...LOW LEVEL THICKNESSES
OVER CENTRAL NC ARE FORECAST TO REACH AROUND 1375M THURSDAY AND
1385M ON FRIDAY...AIDED BY A STEADY SOUTHWESTERLY PRE-FRONTAL WIND.
CLOUD COVER WILL BE MORE WIDESPREAD WEST OF THE MOUNTAINS NEAR THE
FRONTAL ZONE...AND SOME BREAKS ARE POSSIBLE AS MORNING STRATUS BURNS
OFF AND HIGH CLOUD ABATE. HIGHS EACH DAY SHOULD REACH THE UPPER 60S
TO MID 70S...WITH FRIDAY BEING THE WARMEST DAY WHEN SOME EASTERN
COUNTIES COULD PUSH 80.
THE COLD FRONT AND ASSOCIATED MAINLY ANAFRONTAL PRECIP WILL MOVE
INTO CENTRAL NC LATE FRIDAY NIGHT AND EARLY SATURDAY. MODELS ARE IN
DECENT AGREEMENT ON THE TIMING OF THE FROPA...THOUGH THE 00Z ECMWF
IS A LITTLE SLOWER...AND CONFIDENCE IN THE EXACT TIMING OF THE FRONT
STILL REMAINS MEDIUM. THE SURFACE FRONT IS FORECAST TO PUSH SOUTH
OF THE NC/SC BORDER BY SATURDAY EVENING...BUT WITH THE 850MB FLOW
REMAINING OUT OF THE SOUTHWEST AND A 1030MB HIGH PRESSURE BUILDING
OVER NEW ENGLAND...A COLD AIR DAMMING EVENT SHOULD BEGIN TO QUICKLY
EVOLVE SATURDAY NIGHT INTO SUNDAY. THIS WILL BE ACCENTUATED BY AN
UPPER TROUGH DIGGING THROUGH THE CENTRAL US AND A SURFACE LOW MOVING
ACROSS THE MIDWEST AND GREAT LAKES ON SUNDAY. MUCH COLDER TEMPS
FALLING THROUGH THE 40S ON SATURDAY WILL BOTTOM OUT IN THE LOW TO
MID 30S SATURDAY NIGHT AND LIKELY HOLD IN THE 30S ON SUNDAY. AS THE
SURFACE HIGH...WHICH SHOULD BE PROGRESSIVE...MOVES OVER THE
NORTHEAST US...1000-850MB THICKNESSES MAY HOVER AROUND 1300M AND THE
WETBULB FREEZING LINE MAY MEANDER AROUND THE NORTHWEST PIEDMONT
SUNDAY MORNING. THIS WILL NEED TO BE MONITORED WITH SUBSEQUENT MODEL
RUNS...BUT OVERALL CONDITIONS DONT LOOK FAVORABLE FOR MORE THAN
BRIEF FREEZING RAIN.
ON THE HEELS OF THE AFOREMENTIONED SURFACE LOW....A COLD FRONT WILL
SWEEP ACROSS THE AREA MONDAY AND THE WEATHER SHOULD IMPROVE FOR THE
MIDDLE OF NEXT WEEK.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 705 AM TUESDAY...
SUB-VFR CONDITIONS ARE EXPECTED TO DEVELOP AT CENTRAL NC TAF SITES
DURING THIS 24 HR PERIOD. THE CURRENT VFR CONDITIONS WILL PERSIST
UNTIL AROUND 16Z (INT/GSO) TO 19Z (RDU/FAY) TO 21Z (RWI)... WHEN
CIGS ARE LIKELY TO DROP TO MVFR AS THE WARM FRONTAL ZONE APPROACHES
FROM THE SW AND MOISTURE SURGES TO THE NE UP AND OVER THE FRONTAL
ZONE. MVFR CIGS/VSBY SHOULD DOMINATE AT INT/GSO THROUGH 00Z WED...
THEN CIGS AT ALL SITES ARE LIKELY TO RISE BACK UP TO VFR FOR A FEW
HOURS BETWEEN 01Z AND 07Z. AFTER 07Z... ANOTHER SURGE IN LOW LEVEL
MOISTURE WILL CAUSE CIGS TO DROP BACK DOWN TO MVFR THEN TO IFR AT
ALL SITES AFTER 09Z... WITH MVFR TO IFR VSBYS. WINDS WILL BECOME
SWRLY TODAY AT SPEEDS UNDER 8 KTS.
LOOKING BEYOND 12Z WED... SUB-VFR CONDITIONS ARE EXPECTED TO
DOMINATE AT ALL SITES WED INTO THU WITH LOW MVFR-IFR CIGS AND SOME
MAINLY NIGHTTIME/MORNING MVFR FOG WITHIN A MOIST FLOW FROM THE SW.
THESE POOR AVIATION CONDITIONS MAY LAST THROUGH FRI INTO SAT AS WELL
AS A COLD FRONT MOVES SLOWLY INTO THE AREA FROM THE WNW... BRINGING
INCREASING RAIN CHANCES. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
308 AM EST TUE DEC 3 2013
.SYNOPSIS...COASTAL LOW PRESSURE WILL MOVE NORTHEAST AWAY FROM NORTH
CAROLINA THIS MORNING. WEAK HIGH PRESSURE WILL BUILD OVER THE AREA
TODAY AND TONIGHT...THEN SHIFT OFFSHORE WEDNESDAY AS A WARM FRONT
APPROACHES FROM THE SOUTH.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 235 AM TUESDAY...
TODAY WILL MARK THE START OF A PERIOD OF VERY LITTLE SUNSHINE. THE
LATEST SURFACE ANALYSIS SHOWS THE LOW OFF THE NRN NC OUTER BANKS
(ALONG THE OLD FRONT) HEADING ENE AWAY FROM OUR AREA (PUSHED BY THE
BAGGY MID LEVEL TROUGH NOW CROSSING THE AREA)... WHILE WEAK NARROW
HIGH PRESSURE SLIDES IN FROM THE WEST. THIS SURFACE RIDGE WILL BE
PROGRESSIVE... MOVING TO OUR EAST THIS AFTERNOON AS A LOW LEVEL WARM
FRONTAL ZONE (NOW STRETCHING ACROSS E TN THROUGH GA) HEADS SLOWLY NE
TOWARD CENTRAL NC. PATCHY LIGHT RAIN OVER AL/GA (FUELED IN PART BY
LOW LEVEL MOIST UPGLIDE AND WEAK MID LEVEL DPVA) IS MOVING EASTWARD
INTO SC AND SW NC... AND THE LATEST HRRR RUNS BRING THIS INTO OUR
FAR SW CWA EARLY THIS MORNING BEFORE IT DISSIPATES... SUPPORTING THE
IDEA THAT IT WILL ENCOUNTER ENOUGH LOW LEVEL DRY AIR IN PLACE TO BE
OF LITTLE CONSEQUENCE. WILL RETAIN A LOW CHANCE OF A SPRINKLE IN THE
SW THROUGH JUST PAST DAYBREAK. LOW LEVEL MOISTURE SHOULD CONTINUE TO
INCREASE FROM SW TO NE ACROSS CENTRAL NC THROUGH TODAY... WITH NE
SECTIONS SEEING THE MOST SUNSHINE (ALTHOUGH THIS TOO SHOULD BE
FILTERED) AND THE WEST SEEING VERY LITTLE SUN AS THE LOW LEVEL MOIST
UPGLIDE AT 290-300K RAMPS UP AND DEEPENS EARLY. MODELS DEPICT A VERY
WEAK MID LEVEL WAVE TRACKING FROM THE CENTRAL PLAINS THROUGH THE
MIDATLANTIC AREA TONIGHT... AND THE INCREASING MOISTURE COMBINED
WITH THIS WEAK LIFT ALOFT AND ALSO-WEAK LOWER-LEVEL LIFT WITH THE
APPROACHING WARM FRONT (EXPECTED TO PUSH THROUGH SC TOWARD THE NC
BORDER BY MIDNIGHT AND INTO FAR SRN AND SE NC OVERNIGHT) INCLUDING
WEAK 850 MB MASS CONVERGENCE WARRANTS A CHANCE OF LIGHT RAIN OVER
THE WRN AND EXTREME SRN CWA STARTING LATE THIS AFTERNOON GOING INTO
THIS EVENING. EXPECT LOW CHANCES TO THEN SPREAD NORTHWARD THROUGH NC
OVERNIGHT... BUT THE ANTECEDENT DRIER AIR HERE AND WEAK NATURE OF
THE ASCENT SHOULD GREATLY LIMIT COVERAGE AND AMOUNTS FARTHER NORTH.
THIS POP SCENARIO IS SUPPORTED BY THE SREF AND LATEST HI-RES WRF
RUNS. THE COOLEST TEMPS ACROSS THE AREA TODAY SHOULD BE IN THE SW
WHERE CLOUDS WILL BE THICKEST AND MOST PERSISTENT. THICKNESSES STILL
A BIT BELOW NORMAL FAVOR BELOW-NORMAL HIGHS OF 57-62. MILD LOWS OF
43-50... INCLUDING A SMALL UPWARD BUMP IN THE SOUTHERN CWA WITH
THICK CLOUDS AND THE NEARING WARM FRONT. -GIH
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 305 AM TUESDAY...
THE LOW LEVEL WARM FRONT IS EXPECTED TO CONTINUE ITS SLOW NORTHWARD
PROGRESSION THROUGH NC... ALTHOUGH THE MODELS SUGGEST THAT WHILE THE
925-850 MB FRONT SHOULD PROGRESS TO OUR NORTH... THE SURFACE WARM
FRONTAL ZONE MAY NOT QUITE GET ALL OF THE WAY THROUGH OUR CWA AS A
POCKET OF WEAKLY STABLE AIR MAY LINGER OVER THE NW PIEDMONT. WITHIN
THE DEEP SW FLOW... HIGH PW AIR WILL CONTINUE TO FUNNEL INTO
CENTRAL/ERN NC WITH VALUES AT OR OVER 1 INCH... NEAR OR EXCEEDING
200% OF NORMAL... WITH STEADY MOIST ISENTROPIC UPGLIDE OVER THE
AREA... PARTICULARLY WED MORNING... DECREASING AS THE WARM FRONT
JUST ALOFT SHIFTS TO OUR NORTH WITH UPGLIDE BECOMING WEAKER AND MORE
SHALLOW. THE EARLIER FORECAST SHOWS THIS TREND FAIRLY WELL... WITH
SLIGHT CHANCE POPS AND LOWER AMOUNTS IN THE NW WITH CHANCE POPS AND
A BIT MORE OVER THE SE CWA. WITH DECENT AGREEMENT ON THIS PATTERN
AMONGST THE MOST RECENT MODELS RUNS... WILL RETAIN THIS
CONFIGURATION... FOCUSING THE HIGHER (BUT STILL LESS THAN A 40%
CHANCE) POPS IN THE SE IN THE MORNING BEFORE TAPERING THEM OFF IN
THE AFTERNOON WITH THE DEPARTURE OF THE BETTER (YET STILL MODEST)
FORCING FOR ASCENT AND A BRIEF DIP IN THE PRECIP WATER. THE FLAT
FLOW ALOFT THAT IS GENTLY ANTICYCLONIC AND THE FOCUS OF THE WEAK
FORCING CONFINED TO THE LOWER ALTITUDES WILL LIMIT OVERALL PRECIP
TOTALS. EXPECT IT TO REMAIN MOSTLY CLOUDY TO CLOUDY... ESPECIALLY
OVERNIGHT AS ANOTHER SURGE IN VERY HIGH PW SPREADS IN FROM THE SW.
HIGHS FROM NEAR 60 NW (WHERE THE SLIGHTLY COOLER AND MORE STABLE AIR
WILL HOLD ON LONGER INTO WED) TO AROUND 70 SE (THANKS TO THICKNESSES
CLIMBING WELL ABOVE NORMAL). MILD LOWS 53-58. -GIH
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 250 AM MONDAY...
AN AMPLIFIED LONGWAVE PATTERN IN THE MEDIUM RANGE WILL FEATURE A
TROUGH OVER THE WESTERN US AND A RIDGE OVER THE WESTERN
ATLANTIC...WHICH WILL LEAD TO SPEEDY SOUTHWESTERLY FLOW ALOFT
BETWEEN THE TWO AND ACTIVE WESTERN OVER THE EASTERN US. AHEAD OF A
SLOWLY EVOLVING COLD FRONT OVER THE MIDWEST...LOW LEVEL THICKNESSES
OVER CENTRAL NC ARE FORECAST TO REACH AROUND 1375M THURSDAY AND
1385M ON FRIDAY...AIDED BY A STEADY SOUTHWESTERLY PRE-FRONTAL WIND.
CLOUD COVER WILL BE MORE WIDESPREAD WEST OF THE MOUNTAINS NEAR THE
FRONTAL ZONE...AND SOME BREAKS ARE POSSIBLE AS MORNING STRATUS BURNS
OFF AND HIGH CLOUD ABATE. HIGHS EACH DAY SHOULD REACH THE UPPER 60S
TO MID 70S...WITH FRIDAY BEING THE WARMEST DAY WHEN SOME EASTERN
COUNTIES COULD PUSH 80.
THE COLD FRONT AND ASSOCIATED MAINLY ANAFRONTAL PRECIP WILL MOVE
INTO CENTRAL NC LATE FRIDAY NIGHT AND EARLY SATURDAY. MODELS ARE IN
DECENT AGREEMENT ON THE TIMING OF THE FROPA...THOUGH THE 00Z ECMWF
IS A LITTLE SLOWER...AND CONFIDENCE IN THE EXACT TIMING OF THE FRONT
STILL REMAINS MEDIUM. THE SURFACE FRONT IS FORECAST TO PUSH SOUTH
OF THE NC/SC BORDER BY SATURDAY EVENING...BUT WITH THE 850MB FLOW
REMAINING OUT OF THE SOUTHWEST AND A 1030MB HIGH PRESSURE BUILDING
OVER NEW ENGLAND...A COLD AIR DAMMING EVENT SHOULD BEGIN TO QUICKLY
EVOLVE SATURDAY NIGHT INTO SUNDAY. THIS WILL BE ACCENTUATED BY AN
UPPER TROUGH DIGGING THROUGH THE CENTRAL US AND A SURFACE LOW MOVING
ACROSS THE MIDWEST AND GREAT LAKES ON SUNDAY. MUCH COLDER TEMPS
FALLING THROUGH THE 40S ON SATURDAY WILL BOTTOM OUT IN THE LOW TO
MID 30S SATURDAY NIGHT AND LIKELY HOLD IN THE 30S ON SUNDAY. AS THE
SURFACE HIGH...WHICH SHOULD BE PROGRESSIVE...MOVES OVER THE
NORTHEAST US...1000-850MB THICKNESSES MAY HOVER AROUND 1300M AND THE
WETBULB FREEZING LINE MAY MEANDER AROUND THE NORTHWEST PIEDMONT
SUNDAY MORNING. THIS WILL NEED TO BE MONITORED WITH SUBSEQUENT MODEL
RUNS...BUT OVERALL CONDITIONS DONT LOOK FAVORABLE FOR MORE THAN
BRIEF FREEZING RAIN.
ON THE HEELS OF THE AFOREMENTIONED SURFACE LOW....A COLD FRONT WILL
SWEEP ACROSS THE AREA MONDAY AND THE WEATHER SHOULD IMPROVE FOR THE
MIDDLE OF NEXT WEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 100 AM TUESDAY...
SUB-VFR CONDITIONS ARE EXPECTED TO DEVELOP AT CENTRAL NC TAF SITES
DURING THIS 24 HR PERIOD... BUT THE TIMING AND HAZARDS WILL DIFFER
AT EACH LOCATION. AT INT/GSO... VFR CONDITIONS WILL PERSIST UNTIL
AROUND 17Z WHEN CIGS ARE LIKELY TO DROP TO MVFR AS THE WARM FRONTAL
ZONE APPROACHES FROM THE SW. MVFR CIGS/VSBY SHOULD DOMINATE AT
INT/GSO THROUGH 06Z WED. AT FAY... CIGS WILL STAY VFR THIS MORNING
BUT MVFR VSBYS IN FOG ARE EXPECTED 06Z-13Z WITH BRIEF IFR VSBYS
POSSIBLE. CIGS SHOULD DROP TO MVFR AFTER 18Z... THEN IMPROVE BACK UP
TO VFR AFTER 23Z. AT RDU/RWI... BRIEF MVFR VSBYS IN FOG ARE POSSIBLE
THROUGH 13Z THIS MORNING BUT OTHERWISE VFR CONDITIONS SHOULD STILL
DOMINATE THROUGH MIDDAY. CIGS MAY DROP TO MVFR AFTER 19Z BEFORE
RISING BACK TO VFR AFTER 23Z. WINDS WILL STAY LIGHT/VARIABLE THIS
MORNING THEN BECOME PREDOMINANTLY FROM THE SW OR SOUTH UNDER 8 KTS.
LOOKING BEYOND 06Z WED... SUB-VFR CONDITIONS ARE EXPECTED TO
DOMINATE AT ALL SITES FOR WED INTO THU WITH LOW CIGS AND SOME MAINLY
NIGHTTIME/MORNING FOG WITHIN A MOIST FLOW FROM THE SW. THESE POOR
AVIATION CONDITIONS MAY LAST THROUGH FRI INTO SAT AS WELL AS A COLD
FRONT MOVES SLOWLY INTO THE AREA FROM THE WNW... BRINGING INCREASING
RAIN CHANCES. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
250 AM EST TUE DEC 3 2013
.SYNOPSIS...COASTAL LOW PRESSURE WILL MOVE NORTHEAST AWAY FROM NORTH
CAROLINA THIS MORNING. WEAK HIGH PRESSURE WILL BUILD OVER THE AREA
TODAY AND TONIGHT...THEN SHIFT OFFSHORE WEDNESDAY AS A WARM FRONT
APPROACHES FROM THE SOUTH.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 235 AM TUESDAY...
TODAY WILL MARK THE START OF A PERIOD OF VERY LITTLE SUNSHINE. THE
LATEST SURFACE ANALYSIS SHOWS THE LOW OFF THE NRN NC OUTER BANKS
(ALONG THE OLD FRONT) HEADING ENE AWAY FROM OUR AREA (PUSHED BY THE
BAGGY MID LEVEL TROUGH NOW CROSSING THE AREA)... WHILE WEAK NARROW
HIGH PRESSURE SLIDES IN FROM THE WEST. THIS SURFACE RIDGE WILL BE
PROGRESSIVE... MOVING TO OUR EAST THIS AFTERNOON AS A LOW LEVEL WARM
FRONTAL ZONE (NOW STRETCHING ACROSS E TN THROUGH GA) HEADS SLOWLY NE
TOWARD CENTRAL NC. PATCHY LIGHT RAIN OVER AL/GA (FUELED IN PART BY
LOW LEVEL MOIST UPGLIDE AND WEAK MID LEVEL DPVA) IS MOVING EASTWARD
INTO SC AND SW NC... AND THE LATEST HRRR RUNS BRING THIS INTO OUR
FAR SW CWA EARLY THIS MORNING BEFORE IT DISSIPATES... SUPPORTING THE
IDEA THAT IT WILL ENCOUNTER ENOUGH LOW LEVEL DRY AIR IN PLACE TO BE
OF LITTLE CONSEQUENCE. WILL RETAIN A LOW CHANCE OF A SPRINKLE IN THE
SW THROUGH JUST PAST DAYBREAK. LOW LEVEL MOISTURE SHOULD CONTINUE TO
INCREASE FROM SW TO NE ACROSS CENTRAL NC THROUGH TODAY... WITH NE
SECTIONS SEEING THE MOST SUNSHINE (ALTHOUGH THIS TOO SHOULD BE
FILTERED) AND THE WEST SEEING VERY LITTLE SUN AS THE LOW LEVEL MOIST
UPGLIDE AT 290-300K RAMPS UP AND DEEPENS EARLY. MODELS DEPICT A VERY
WEAK MID LEVEL WAVE TRACKING FROM THE CENTRAL PLAINS THROUGH THE
MIDATLANTIC AREA TONIGHT... AND THE INCREASING MOISTURE COMBINED
WITH THIS WEAK LIFT ALOFT AND ALSO-WEAK LOWER-LEVEL LIFT WITH THE
APPROACHING WARM FRONT (EXPECTED TO PUSH THROUGH SC TOWARD THE NC
BORDER BY MIDNIGHT AND INTO FAR SRN AND SE NC OVERNIGHT) INCLUDING
WEAK 850 MB MASS CONVERGENCE WARRANTS A CHANCE OF LIGHT RAIN OVER
THE WRN AND EXTREME SRN CWA STARTING LATE THIS AFTERNOON GOING INTO
THIS EVENING. EXPECT LOW CHANCES TO THEN SPREAD NORTHWARD THROUGH NC
OVERNIGHT... BUT THE ANTECEDENT DRIER AIR HERE AND WEAK NATURE OF
THE ASCENT SHOULD GREATLY LIMIT COVERAGE AND AMOUNTS FARTHER NORTH.
THIS POP SCENARIO IS SUPPORTED BY THE SREF AND LATEST HI-RES WRF
RUNS. THE COOLEST TEMPS ACROSS THE AREA TODAY SHOULD BE IN THE SW
WHERE CLOUDS WILL BE THICKEST AND MOST PERSISTENT. THICKNESSES STILL
A BIT BELOW NORMAL FAVOR BELOW-NORMAL HIGHS OF 57-62. MILD LOWS OF
43-50... INCLUDING A SMALL UPWARD BUMP IN THE SOUTHERN CWA WITH
THICK CLOUDS AND THE NEARING WARM FRONT. -GIH
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 PM MONDAY...
TO BE UPDATED SHORTLY...
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 250 AM MONDAY...
AN AMPLIFIED LONGWAVE PATTERN IN THE MEDIUM RANGE WILL FEATURE A
TROUGH OVER THE WESTERN US AND A RIDGE OVER THE WESTERN
ATLANTIC...WHICH WILL LEAD TO SPEEDY SOUTHWESTERLY FLOW ALOFT
BETWEEN THE TWO AND ACTIVE WESTERN OVER THE EASTERN US. AHEAD OF A
SLOWLY EVOLVING COLD FRONT OVER THE MIDWEST...LOW LEVEL THICKNESSES
OVER CENTRAL NC ARE FORECAST TO REACH AROUND 1375M THURSDAY AND
1385M ON FRIDAY...AIDED BY A STEADY SOUTHWESTERLY PRE-FRONTAL WIND.
CLOUD COVER WILL BE MORE WIDESPREAD WEST OF THE MOUNTAINS NEAR THE
FRONTAL ZONE...AND SOME BREAKS ARE POSSIBLE AS MORNING STRATUS BURNS
OFF AND HIGH CLOUD ABATE. HIGHS EACH DAY SHOULD REACH THE UPPER 60S
TO MID 70S...WITH FRIDAY BEING THE WARMEST DAY WHEN SOME EASTERN
COUNTIES COULD PUSH 80.
THE COLD FRONT AND ASSOCIATED MAINLY ANAFRONTAL PRECIP WILL MOVE
INTO CENTRAL NC LATE FRIDAY NIGHT AND EARLY SATURDAY. MODELS ARE IN
DECENT AGREEMENT ON THE TIMING OF THE FROPA...THOUGH THE 00Z ECMWF
IS A LITTLE SLOWER...AND CONFIDENCE IN THE EXACT TIMING OF THE FRONT
STILL REMAINS MEDIUM. THE SURFACE FRONT IS FORECAST TO PUSH SOUTH
OF THE NC/SC BORDER BY SATURDAY EVENING...BUT WITH THE 850MB FLOW
REMAINING OUT OF THE SOUTHWEST AND A 1030MB HIGH PRESSURE BUILDING
OVER NEW ENGLAND...A COLD AIR DAMMING EVENT SHOULD BEGIN TO QUICKLY
EVOLVE SATURDAY NIGHT INTO SUNDAY. THIS WILL BE ACCENTUATED BY AN
UPPER TROUGH DIGGING THROUGH THE CENTRAL US AND A SURFACE LOW MOVING
ACROSS THE MIDWEST AND GREAT LAKES ON SUNDAY. MUCH COLDER TEMPS
FALLING THROUGH THE 40S ON SATURDAY WILL BOTTOM OUT IN THE LOW TO
MID 30S SATURDAY NIGHT AND LIKELY HOLD IN THE 30S ON SUNDAY. AS THE
SURFACE HIGH...WHICH SHOULD BE PROGRESSIVE...MOVES OVER THE
NORTHEAST US...1000-850MB THICKNESSES MAY HOVER AROUND 1300M AND THE
WETBULB FREEZING LINE MAY MEANDER AROUND THE NORTHWEST PIEDMONT
SUNDAY MORNING. THIS WILL NEED TO BE MONITORED WITH SUBSEQUENT MODEL
RUNS...BUT OVERALL CONDITIONS DONT LOOK FAVORABLE FOR MORE THAN
BRIEF FREEZING RAIN.
ON THE HEELS OF THE AFOREMENTIONED SURFACE LOW....A COLD FRONT WILL
SWEEP ACROSS THE AREA MONDAY AND THE WEATHER SHOULD IMPROVE FOR THE
MIDDLE OF NEXT WEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 100 AM TUESDAY...
SUB-VFR CONDITIONS ARE EXPECTED TO DEVELOP AT CENTRAL NC TAF SITES
DURING THIS 24 HR PERIOD... BUT THE TIMING AND HAZARDS WILL DIFFER
AT EACH LOCATION. AT INT/GSO... VFR CONDITIONS WILL PERSIST UNTIL
AROUND 17Z WHEN CIGS ARE LIKELY TO DROP TO MVFR AS THE WARM FRONTAL
ZONE APPROACHES FROM THE SW. MVFR CIGS/VSBY SHOULD DOMINATE AT
INT/GSO THROUGH 06Z WED. AT FAY... CIGS WILL STAY VFR THIS MORNING
BUT MVFR VSBYS IN FOG ARE EXPECTED 06Z-13Z WITH BRIEF IFR VSBYS
POSSIBLE. CIGS SHOULD DROP TO MVFR AFTER 18Z... THEN IMPROVE BACK UP
TO VFR AFTER 23Z. AT RDU/RWI... BRIEF MVFR VSBYS IN FOG ARE POSSIBLE
THROUGH 13Z THIS MORNING BUT OTHERWISE VFR CONDITIONS SHOULD STILL
DOMINATE THROUGH MIDDAY. CIGS MAY DROP TO MVFR AFTER 19Z BEFORE
RISING BACK TO VFR AFTER 23Z. WINDS WILL STAY LIGHT/VARIABLE THIS
MORNING THEN BECOME PREDOMINANTLY FROM THE SW OR SOUTH UNDER 8 KTS.
LOOKING BEYOND 06Z WED... SUB-VFR CONDITIONS ARE EXPECTED TO
DOMINATE AT ALL SITES FOR WED INTO THU WITH LOW CIGS AND SOME MAINLY
NIGHTTIME/MORNING FOG WITHIN A MOIST FLOW FROM THE SW. THESE POOR
AVIATION CONDITIONS MAY LAST THROUGH FRI INTO SAT AS WELL AS A COLD
FRONT MOVES SLOWLY INTO THE AREA FROM THE WNW... BRINGING INCREASING
RAIN CHANCES. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...VINCENT
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
235 AM EST TUE DEC 3 2013
.SYNOPSIS...COASTAL LOW PRESSURE WILL MOVE NORTHEAST AWAY FROM NORTH
CAROLINA THIS MORNING. WEAK HIGH PRESSURE WILL BUILD OVER THE AREA
TODAY AND TONIGHT...THEN SHIFT OFFSHORE WEDNESDAY AS A WARM FRONT
APPROACHES FROM THE SOUTH.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 235 AM TUESDAY...
TODAY WILL MARK THE START OF A PERIOD OF VERY LITTLE SUNSHINE. THE
LATEST SURFACE ANALYSIS SHOWS THE LOW OFF THE NRN NC OUTER BANKS
(ALONG THE OLD FRONT) HEADING ENE AWAY FROM OUR AREA (PUSHED BY THE
BAGGY MID LEVEL TROUGH NOW CROSSING THE AREA)... WHILE WEAK NARROW
HIGH PRESSURE SLIDES IN FROM THE WEST. THIS SURFACE RIDGE WILL BE
PROGRESSIVE... MOVING TO OUR EAST THIS AFTERNOON AS A LOW LEVEL WARM
FRONTAL ZONE (NOW STRETCHING ACROSS E TN THROUGH GA) HEADS SLOWLY NE
TOWARD CENTRAL NC. PATCHY LIGHT RAIN OVER AL/GA (FUELED IN PART BY
LOW LEVEL MOIST UPGLIDE AND WEAK MID LEVEL DPVA) IS MOVING EASTWARD
INTO SC AND SW NC... AND THE LATEST HRRR RUNS BRING THIS INTO OUR
FAR SW CWA EARLY THIS MORNING BEFORE IT DISSIPATES... SUPPORTING THE
IDEA THAT IT WILL ENCOUNTER ENOUGH LOW LEVEL DRY AIR IN PLACE TO BE
OF LITTLE CONSEQUENCE. WILL RETAIN A LOW CHANCE OF A SPRINKLE IN THE
SW THROUGH JUST PAST DAYBREAK. LOW LEVEL MOISTURE SHOULD CONTINUE TO
INCREASE FROM SW TO NE ACROSS CENTRAL NC THROUGH TODAY... WITH NE
SECTIONS SEEING THE MOST SUNSHINE (ALTHOUGH THIS TOO SHOULD BE
FILTERED) AND THE WEST SEEING VERY LITTLE SUN AS THE LOW LEVEL MOIST
UPGLIDE AT 290-300K RAMPS UP AND DEEPENS EARLY. MODELS DEPICT A VERY
WEAK MID LEVEL WAVE TRACKING FROM THE CENTRAL PLAINS THROUGH THE
MIDATLANTIC AREA TONIGHT... AND THE INCREASING MOISTURE COMBINED
WITH THIS WEAK LIFT ALOFT AND ALSO-WEAK LOWER-LEVEL LIFT WITH THE
APPROACHING WARM FRONT (EXPECTED TO PUSH THROUGH SC TOWARD THE NC
BORDER BY MIDNIGHT AND INTO FAR SRN AND SE NC OVERNIGHT) INCLUDING
WEAK 850 MB MASS CONVERGENCE WARRANTS A CHANCE OF LIGHT RAIN OVER
THE WRN AND EXTREME SRN CWA STARTING LATE THIS AFTERNOON GOING INTO
THIS EVENING. EXPECT LOW CHANCES TO THEN SPREAD NORTHWARD THROUGH NC
OVERNIGHT... BUT THE ANTECEDENT DRIER AIR HERE AND WEAK NATURE OF
THE ASCENT SHOULD GREATLY LIMIT COVERAGE AND AMOUNTS FARTHER NORTH.
THIS POP SCENARIO IS SUPPORTED BY THE SREF AND LATEST HI-RES WRF
RUNS. THE COOLEST TEMPS ACROSS THE AREA TODAY SHOULD BE IN THE SW
WHERE CLOUDS WILL BE THICKEST AND MOST PERSISTENT. THICKNESSES STILL
A BIT BELOW NORMAL FAVOR BELOW-NORMAL HIGHS OF 57-62. MILD LOWS OF
43-50... INCLUDING A SMALL UPWARD BUMP IN THE SOUTHERN CWA WITH
THICK CLOUDS AND THE NEARING WARM FRONT. -GIH
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 245 PM MONDAY...
WSW FLOW ALOFT ON THE WESTERN PERIPHERY OF AN UPPER LEVEL RIDGE
BUILDING ALONG/JUST OFFSHORE THE EAST COAST WILL GIVE WAY TO
STRENGTHENING SW FLOW ALOFT ACROSS THE CAROLINAS BY FRIDAY AS AN
UPPER LEVEL TROUGH DEEPENS OVER THE ROCKIES/CENTRAL CONUS. IN THE
LOWER LEVELS...A PERSISTENT SOUTHERLY RETURN FLOW /WARM ADVECTION
REGIME/ WILL PREVAIL ON THE WESTERN PERIPHERY OF OFFSHORE HIGH
PRESSURE...WITH INCREASING MOISTURE ACROSS THE CAROLINAS IN THE WED-
FRI TIME FRAME. DESPITE INCREASING CLOUD COVER DOWNSTREAM OF PRECIP
EXPECTED TO DEVELOP ALONG A STRENGTHENING FRONTAL ZONE OVER THE
LOWER MS RIVER VALLEY AND TN/OH VALLEY ON THU/FRI...THERE IS HIGH
CONFIDENCE THAT STRONG WARM ADVECTION WILL RESULT IN A WARMING TREND
EACH DAY...WITH TEMPS IN THE LOWER/MID 70S (ESP. EAST OF HWY 1) BY
FRIDAY.
CONFIDENCE IN PRECIPITATION CHANCES REMAINS LOWER THAN AVERAGE. THE
LATEST MODEL GUIDANCE SUGGESTS A CHANCE OF LIGHT RAIN WED MORNING
THROUGH EARLY WED AFTERNOON IN ASSOC/W INCREASING MOISTURE AND THE
INITIAL SURGE OF STRONG LOW/MID-LEVEL WARM ADVECTION...THOUGH
PRECISE COVERAGE AND TIMING REMAIN DIFFICULT TO ASCERTAIN AT THIS
RANGE. DUE TO INCREASED CLOUD COVER AND A CHANCE OF RAIN...HIGH
TEMPS ON WED COULD RANGE FROM THE UPPER 50S TO UPPER 60S. EXPECT
LITTLE CHANCE FOR PRECIPITATION WED NIGHT THROUGH THE DAYTIME HOURS
ON FRIDAY GIVEN VERY LITTLE FORCING (ASIDE FROM TRANSIENT SMALL
AMPLITUDE WAVES IN SW FLOW ALOFT) AS THE AFOREMENTIONED FRONTAL ZONE
SLOWLY APPROACHES THE MOUNTAINS FROM THE WEST. WILL INDICATE LARGELY
DRY CONDITIONS WED NIGHT THROUGH FRIDAY. HIGHS WILL PRIMARILY DEPEND
ON CLOUD COVER THU/FRI...RANGING FROM THE MID/UPPER 60S NW (MORE
CLOUD COVER) TO LOWER 70S SE ON THU...AND UPPER 60S NW TO MID 70S SE
ON FRI. -VINCENT
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
AS OF 345 PM MONDAY...
FRI NIGHT THROUGH SAT: DESPITE BEING 120+ HOURS OUT...FORECAST
CONFIDENCE REMAINS HIGH THAT A STRONG COLD FRONT WILL PROGRESS
THROUGH CENTRAL NC FRIDAY NIGHT AND SATURDAY MORNING...THOUGH THE
PRECISE TIMING IS STILL DIFFICULT TO ASCERTAIN THIS FAR OUT IN THE
FCST AND WILL HIGHLY AFFECT BOTH LOW TEMPS FRI NIGHT AND HIGHS ON
SAT. PRECIP AMOUNTS ALONG AND BEHIND THE COLD FRONT APPEAR GENERALLY
ON THE LOWER END OF THE SPECTRUM. WITHOUT MUCH IN THE WAY OF UPPER
LEVEL FORCING AND UNIDIRECTIONAL SW FLOW ALOFT...FORCING WILL
PRIMARILY BE CONFINED TO LOW-LEVEL CONVERGENCE ALONG THE SFC FRONT
AND WARM ADVECTION OVER/BEHIND THE SURFACE FRONT PROGRESSING E/SE
THROUGH THE CAROLINAS...WITH THE 925-850 MB TROUGH LAGGING BEHIND.
WILL MAINTAIN PRECIP CHANCES ~60% LATE FRI NIGHT THROUGH EARLY SAT
AFTERNOON. THEREAFTER...PRECIP CHANCES MAY LARGELY END SAT AFT/EVE
ASIDE FROM A POTENTIAL FOR PATCHY DRIZZLE. TEMPS WILL FALL FROM THE
60S LATE FRI EVENING TO THE 40S FROM NW-SE SATURDAY MORNING THROUGH
EARLY SAT AFTERNOON...LIKELY CONTINUING TO FALL MID/LATE SAT
AFTERNOON AS STRONG/COLD HIGH PRESSURE OVER THE UPPER MIDWEST
PROGRESSES EAST INTO THE GREAT LAKES RESULTING IN FURTHER PRESSURE
RISES /COLD ADVECTION/ LATE SAT INTO SAT NIGHT...WITH A PRONOUNCED
SFC RIDGE AXIS EXTENDING SOUTHWARD INTO THE CAROLINAS.
SATURDAY NIGHT THROUGH MONDAY: AN UPPER LEVEL TROUGH DIGGING INTO
THE 4-CORNERS REGION SAT IS PROGGED TO TRACK EAST INTO THE CENTRAL
PLAINS SAT NIGHT...AFFECTING THE LOW-LEVEL HEIGHT PATTERN
(BACKING/STRENGTHENING LOW-LEVEL FLOW) OVER THE SOUTHEAST CONUS AND
ENHANCING WARM ADVECTION /ISENTROPIC LIFT/ ATOP THE STRONG SFC RIDGE
AXIS /CAD WEDGE/ OVER THE CAROLINAS. AS A RESULT...AFTER A BRIEF
LULL SAT AFT/EVE LIGHT RAIN COULD RE-DEVELOP FROM SOUTH-NORTH SAT
NIGHT. LOWS SAT NIGHT WILL HIGHLY DEPEND ON THE PRECISE NATURE OF
THE COLD/DRY AIRMASS ADVECTING INTO THE REGION AND ANY POTENTIAL
EVAP COOLING ASSOC/W PRECIPITATION THAT MAY RE-DEVELOP...AND IT IS
POSSIBLE THAT PTYPE ISSUES (I.E. FZRA) COULD BE AN ISSUE IN THE NW
PIEDMONT. HOWEVER...AT THIS RANGE CONFIDENCE IS TOO LOW W/REGARD TO
THE SPECIFICS AND WILL MENTION ALL RAIN WITH LOWS IN THE MID 30S
(NW) TO UPPER 30S (SE). THE UPPER LEVEL WAVE IS EXPECTED TO
DEAMPLIFY AS IT TRACKS INTO THE TN VALLEY AND MID-ATLANTIC SUN AND
SUN NIGHT. EXPECT OVERCAST SKIES/RAIN AND NEAR STEADY TEMPS IN THE
30S TO PERHAPS 40S IN FAR SE COASTAL PLAIN ON SUNDAY IN ASSOC/W A
STRONG CAD WEDGE AND EVOLVING WEAK MILLER-B CYCLONE. FROM A PATTERN
RECOGNITION STANDPOINT...BASED ON THE LATEST GUIDANCE...FZRA AND
SOME POTENTIAL FOR ICE ACCUMULATION CANNOT BE RULED OUT IN THE NW
PIEDMONT ON SUNDAY...DEPENDING ON THE PRECISE NATURE/TIMING OF THE
AIRMASS ADVECTING INTO THE REGION FROM THE NORTH AND THE EVOLUTION
OF THE AFOREMENTIONED MILLER-B CYCLONE. DUE TO SIGNIFICANT
UNCERTAINTY AT THIS RANGE...WILL MENTION ONLY RAIN IN THE OFFICIAL
FORECAST. PRECIPITATION WILL END FROM W-E SUN NIGHT IN ASSOC/W A
COLD FRONTAL PASSAGE FROM THE WEST AS THE PRIMARY SFC CYCLONE
CONSOLIDATES ALONG THE MID-ATLANTIC COAST AND TRACKS NE AWAY FROM
THE REGION. -VINCENT
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 100 AM TUESDAY...
SUB-VFR CONDITIONS ARE EXPECTED TO DEVELOP AT CENTRAL NC TAF SITES
DURING THIS 24 HR PERIOD... BUT THE TIMING AND HAZARDS WILL DIFFER
AT EACH LOCATION. AT INT/GSO... VFR CONDITIONS WILL PERSIST UNTIL
AROUND 17Z WHEN CIGS ARE LIKELY TO DROP TO MVFR AS THE WARM FRONTAL
ZONE APPROACHES FROM THE SW. MVFR CIGS/VSBY SHOULD DOMINATE AT
INT/GSO THROUGH 06Z WED. AT FAY... CIGS WILL STAY VFR THIS MORNING
BUT MVFR VSBYS IN FOG ARE EXPECTED 06Z-13Z WITH BRIEF IFR VSBYS
POSSIBLE. CIGS SHOULD DROP TO MVFR AFTER 18Z... THEN IMPROVE BACK UP
TO VFR AFTER 23Z. AT RDU/RWI... BRIEF MVFR VSBYS IN FOG ARE POSSIBLE
THROUGH 13Z THIS MORNING BUT OTHERWISE VFR CONDITIONS SHOULD STILL
DOMINATE THROUGH MIDDAY. CIGS MAY DROP TO MVFR AFTER 19Z BEFORE
RISING BACK TO VFR AFTER 23Z. WINDS WILL STAY LIGHT/VARIABLE THIS
MORNING THEN BECOME PREDOMINANTLY FROM THE SW OR SOUTH UNDER 8 KTS.
LOOKING BEYOND 06Z WED... SUB-VFR CONDITIONS ARE EXPECTED TO
DOMINATE AT ALL SITES FOR WED INTO THU WITH LOW CIGS AND SOME MAINLY
NIGHTTIME/MORNING FOG WITHIN A MOIST FLOW FROM THE SW. THESE POOR
AVIATION CONDITIONS MAY LAST THROUGH FRI INTO SAT AS WELL AS A COLD
FRONT MOVES SLOWLY INTO THE AREA FROM THE WNW... BRINGING INCREASING
RAIN CHANCES. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...VINCENT
LONG TERM...VINCENT
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
511 AM CST TUE DEC 3 2013
.AVIATION...
A BAND OF CIRRUS MOVED OVER THE METROPLEX SLOWING THE COOLING A
BIT...BUT IT HAS MOVED EAST OF TAF SITES AND FOG IS STARTING TO
FORM AT DFW AS I WRITE THIS. DENSE FOG REMAINS AS CLOSE AS
DENTON...LANCASTER...AND MESQUITE WHICH APPEARS SIMILAR TO
CONDITIONS YESTERDAY MORNING. HRRR CONTINUES TO SHOW FOG REACHING
DFW AND DAL...BUT NOT THE WESTERN/SOUTHERN SITES. 4KM WRF STOPS
FOG JUST EAST OF TAF SITES AND RUC SOUNDINGS SHOW GROUND FOG.
WITH TWO HOURS TO SUNRISE...CONDITIONS ARE RIPE FOR COOLING TO
CONTINUE AND FOG TO FORM...SO WILL KEEP THE IFR FORECASTS FOR DFW
& DAL. LIKE YESTERDAY...FOG LAYER WILL BE FAIRLY THIN AND SHOULD
BURN OFF QUICKLY AFTER SUNRISE. WITH A STRONG SOUTHWESTERLY LOW
LEVEL JET TOMORROW MORNING...NO RESTRICTIONS TO CIG/VSBY ARE
EXPECTED. 84
&&
.PREV DISCUSSION...
/ISSUED 426 AM CST TUE DEC 3 2013/
STILL SOME MILD WEATHER TO ENJOY BEFORE THE ARCTIC BLAST ARRIVES.
DENSE FOG DEVELOPED OVERNIGHT NORTHEAST OF A BOWIE TO DALLAS TO
CANTON LINE. THIS FOG WILL CONTINUE TO CAUSE SOME PROBLEMS
THROUGH MID MORNING. THUS THE DENSE FOG ADVISORY WILL REMAIN IN
EFFECT UNTIL 10 AM. SOME PATCHY FOG WILL OCCUR FARTHER SOUTH FROM
CORSICANA TO HEARNE EASTWARD...AND IF IT BECOMES WIDESPREAD
ENOUGH WILL EXPAND THE DENSE FOG ADVISORY. AFTER THE FOG BURNS
OFF IT WILL BE A NICE LATE FALL DAY ACROSS THE REGION WITH HIGHS
IN THE UPPER 60S NORTHEAST TO AROUND 80 WEST.
ALTHOUGH TIMING DIFFERENCES BETWEEN THE MODELS CONTINUE CONCERNING
THE NEXT COLD FRONT...THEY HAVE COME CLOSER TO AGREEMENT THAN THEY
WERE 24 HOURS AGO. THE GFS REMAINS THE FASTEST WITH THE FRONT BUT
IS SLOWER THAN IT WAS 24 HOURS AGO...BRINGING THE FRONT INTO THE
NORTHWESTERN ZONES LATE WEDNESDAY MORNING. THE GFS THEN SLOWS
THE SOUTHWARD PROGRESS CONSIDERABLY...BRINGING THE FRONT DOWN
TO A PARIS TO EASTLAND LINE BY 00Z THURSDAY...AND TO A CANTON TO
LAMPASAS BY 12Z THURSDAY. THE ECMWF BRINGS THE FRONT ACROSS THE
RED RIVER AROUND 00Z THURSDAY AND THROUGH THE SOUTHEAST BY 12Z
THURSDAY. THE CMC ALSO BRINGS THE FRONT INTO THE NORTHWEST BY 00Z
THURSDAY BUT BY 12Z...IT PLACES THE FRONT NEAR A TYLER TO TEMPLE
LINE. THE NAM BRINGS THE FRONT DOWN TO A PARIS TO DFW TO HAMILTON
LINE BY 00Z THURSDAY AND THEN THROUGH THE SOUTHEAST BY 12Z
THURSDAY.
THE MODELS AGREE THAT THE FRONT WILL NOT REACH THE I-20 CORRIDOR
UNTIL LATE WEDNESDAY AFTERNOON AT THE EARLIEST AND WILL NOT MOVE
THROUGH THE SOUTHEASTERN COUNTIES UNTIL AROUND OR SHORTLY AFTER
DAYBREAK THURSDAY. THUS HAVE WARMED WEDNESDAY/S TEMPERATURES 5 TO
OVER 10 DEGREES AREA WIDE. LIKEWISE HAVE RAISED THURSDAY MORNINGS
LOWS ACROSS ALL BUT THE NORTHWEST BY 5 TO 10 DEGREES.
THE ARCTIC FRONT WILL MOVE THROUGH NORTH TEXAS THURSDAY WITH MUCH
COLDER TEMPERATURES. THE HIGHS WILL LIKELY OCCUR EARLY MORNING
WITH TEMPERATURES STEADY OR SLOWLY FALLING DURING THE DAY. AN
APPROACHING SHORTWAVE AND UPGLIDE OVER THE FRONT WILL RESULT IN
RAIN STARTING THURSDAY AND INCREASING THURSDAY NIGHT. AS
TEMPERATURES FALL BELOW FREEZING ACROSS THE NORTHWEST...THE RAIN
WILL CHANGE TO FREEZING RAIN THURSDAY NIGHT. BY DAYBREAK FRIDAY
THE FREEZING LINE MAY BE DOWN TO NEAR A SULPHUR SPRINGS TO
KILLEEN LINE. HAVE JUST LEFT A MENTION OF RAIN AT WACO AND
KILLEEN FOR NOW...BUT IT WILL BE CLOSE. THE PRECIPITATION SHOULD
COME TO A TEMPORARY END FROM SOUTHWEST TO NORTHEAST FRIDAY
AFTERNOON AS A SHORTWAVE MOVES OFF TO THE EAST.
UNFORTUNATELY...WITH THE TROUGH STILL BACK TO OUR WEST...WE WILL
REMAIN UNDER THE GUN FOR ADDITIONAL SHORTWAVES TO MOVE ACROSS
OVER THE REGION THE WEEKEND BRINGING A CHANCE OF A WINTRY MIX OF
PRECIPITATION. FORTUNATELY PRECIPITATION AMOUNTS SHOULD NOT BE
HEAVY. THE MAIN TROUGH WILL FINALLY MOVE ACROSS THE SOUTHERN
PLAINS SUNDAY NIGHT...BRINGING AN END TO THE PRECIPITATION
CHANCES BUT COOLER THAN NORMAL TEMPERATURES WILL CONTINUE INTO
THE EARLY PART OF NEXT WEEK.
58
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 74 55 77 43 45 / 0 5 10 20 60
WACO, TX 77 57 79 54 57 / 0 5 10 20 50
PARIS, TX 69 52 72 46 46 / 0 5 5 20 70
DENTON, TX 72 50 73 38 39 / 0 5 5 20 60
MCKINNEY, TX 71 51 75 41 41 / 0 5 10 20 60
DALLAS, TX 74 56 77 44 48 / 0 5 10 20 60
TERRELL, TX 71 57 76 48 48 / 0 5 10 20 60
CORSICANA, TX 74 61 77 53 54 / 0 5 10 20 60
TEMPLE, TX 78 57 79 56 58 / 0 5 10 20 50
MINERAL WELLS, TX 77 52 77 39 40 / 0 5 10 20 60
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR TXZ092>095-
103>107-120>123-135.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
510 AM CST TUE DEC 3 2013
.AVIATION...
A BAND OF CIRRUS MOVED OVER THE METROPLEX SLOWING THE COOLING A
BIT...BUT IT HAS MOVED EAST OF TAF SITES AND FOG IS STARTING TO
FORM AS I WRITE THIS. DENSE FOG REMAINS AS CLOSE AS
DENTON...LANCASTER...AND MESQUITE WHICH APPEARS SIMILAR TO
YESTERDAY. HRRR CONTINUES TO SHOW FOG REACHING DFW AND DAL...BUT
NOT THE WESTERN/SOUTHERN SITES. 4KM WRF STOPS FOG JUST EAST OF
TAF SITES AND RUC SOUNDINGS SHOW GROUND FOG. WITH TWO HOURS TO
SUNRISE...CONDITIONS ARE RIPE FOR COOLING TO CONTINUE AND FOG TO
FORM...SO WILL KEEP THE IFR FORECASTS FOR DFW & DAL. LIKE
YESTERDAY...FOG LAYER WILL BE FAIRLY THIN AND SHOULD BURN OFF
QUICKLY AFTER SUNRISE. WITH A STRONG SOUTHWESTERLY LOW LEVEL JET
TOMORROW MORNING...NO RESTRICTIONS TO CIG/VSBY ARE EXPECTED. 84
&&
.PREV DISCUSSION... /ISSUED 426 AM CST TUE DEC 3 2013/
STILL SOME MILD WEATHER TO ENJOY BEFORE THE ARCTIC BLAST ARRIVES.
DENSE FOG DEVELOPED OVERNIGHT NORTHEAST OF A BOWIE TO DALLAS TO
CANTON LINE. THIS FOG WILL CONTINUE TO CAUSE SOME PROBLEMS
THROUGH MID MORNING. THUS THE DENSE FOG ADVISORY WILL REMAIN IN
EFFECT UNTIL 10 AM. SOME PATCHY FOG WILL OCCUR FARTHER SOUTH FROM
CORSICANA TO HEARNE EASTWARD...AND IF IT BECOMES WIDESPREAD
ENOUGH WILL EXPAND THE DENSE FOG ADVISORY. AFTER THE FOG BURNS
OFF IT WILL BE A NICE LATE FALL DAY ACROSS THE REGION WITH HIGHS
IN THE UPPER 60S NORTHEAST TO AROUND 80 WEST.
ALTHOUGH TIMING DIFFERENCES BETWEEN THE MODELS CONTINUE CONCERNING
THE NEXT COLD FRONT...THEY HAVE COME CLOSER TO AGREEMENT THAN THEY
WERE 24 HOURS AGO. THE GFS REMAINS THE FASTEST WITH THE FRONT BUT
IS SLOWER THAN IT WAS 24 HOURS AGO...BRINGING THE FRONT INTO THE
NORTHWESTERN ZONES LATE WEDNESDAY MORNING. THE GFS THEN SLOWS
THE SOUTHWARD PROGRESS CONSIDERABLY...BRINGING THE FRONT DOWN
TO A PARIS TO EASTLAND LINE BY 00Z THURSDAY...AND TO A CANTON TO
LAMPASAS BY 12Z THURSDAY. THE ECMWF BRINGS THE FRONT ACROSS THE
RED RIVER AROUND 00Z THURSDAY AND THROUGH THE SOUTHEAST BY 12Z
THURSDAY. THE CMC ALSO BRINGS THE FRONT INTO THE NORTHWEST BY 00Z
THURSDAY BUT BY 12Z...IT PLACES THE FRONT NEAR A TYLER TO TEMPLE
LINE. THE NAM BRINGS THE FRONT DOWN TO A PARIS TO DFW TO HAMILTON
LINE BY 00Z THURSDAY AND THEN THROUGH THE SOUTHEAST BY 12Z
THURSDAY.
THE MODELS AGREE THAT THE FRONT WILL NOT REACH THE I-20 CORRIDOR
UNTIL LATE WEDNESDAY AFTERNOON AT THE EARLIEST AND WILL NOT MOVE
THROUGH THE SOUTHEASTERN COUNTIES UNTIL AROUND OR SHORTLY AFTER
DAYBREAK THURSDAY. THUS HAVE WARMED WEDNESDAY/S TEMPERATURES 5 TO
OVER 10 DEGREES AREA WIDE. LIKEWISE HAVE RAISED THURSDAY MORNINGS
LOWS ACROSS ALL BUT THE NORTHWEST BY 5 TO 10 DEGREES.
THE ARCTIC FRONT WILL MOVE THROUGH NORTH TEXAS THURSDAY WITH MUCH
COLDER TEMPERATURES. THE HIGHS WILL LIKELY OCCUR EARLY MORNING
WITH TEMPERATURES STEADY OR SLOWLY FALLING DURING THE DAY. AN
APPROACHING SHORTWAVE AND UPGLIDE OVER THE FRONT WILL RESULT IN
RAIN STARTING THURSDAY AND INCREASING THURSDAY NIGHT. AS
TEMPERATURES FALL BELOW FREEZING ACROSS THE NORTHWEST...THE RAIN
WILL CHANGE TO FREEZING RAIN THURSDAY NIGHT. BY DAYBREAK FRIDAY
THE FREEZING LINE MAY BE DOWN TO NEAR A SULPHUR SPRINGS TO
KILLEEN LINE. HAVE JUST LEFT A MENTION OF RAIN AT WACO AND
KILLEEN FOR NOW...BUT IT WILL BE CLOSE. THE PRECIPITATION SHOULD
COME TO A TEMPORARY END FROM SOUTHWEST TO NORTHEAST FRIDAY
AFTERNOON AS A SHORTWAVE MOVES OFF TO THE EAST.
UNFORTUNATELY...WITH THE TROUGH STILL BACK TO OUR WEST...WE WILL
REMAIN UNDER THE GUN FOR ADDITIONAL SHORTWAVES TO MOVE ACROSS
OVER THE REGION THE WEEKEND BRINGING A CHANCE OF A WINTRY MIX OF
PRECIPITATION. FORTUNATELY PRECIPITATION AMOUNTS SHOULD NOT BE
HEAVY. THE MAIN TROUGH WILL FINALLY MOVE ACROSS THE SOUTHERN
PLAINS SUNDAY NIGHT...BRINGING AN END TO THE PRECIPITATION
CHANCES BUT COOLER THAN NORMAL TEMPERATURES WILL CONTINUE INTO
THE EARLY PART OF NEXT WEEK.
58
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 74 55 77 43 45 / 0 5 10 20 60
WACO, TX 77 57 79 54 57 / 0 5 10 20 50
PARIS, TX 69 52 72 46 46 / 0 5 5 20 70
DENTON, TX 72 50 73 38 39 / 0 5 5 20 60
MCKINNEY, TX 71 51 75 41 41 / 0 5 10 20 60
DALLAS, TX 74 56 77 44 48 / 0 5 10 20 60
TERRELL, TX 71 57 76 48 48 / 0 5 10 20 60
CORSICANA, TX 74 61 77 53 54 / 0 5 10 20 60
TEMPLE, TX 78 57 79 56 58 / 0 5 10 20 50
MINERAL WELLS, TX 77 52 77 39 40 / 0 5 10 20 60
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR TXZ092>095-
103>107-120>123-135.
&&
$$
84/58
AREA FORECAST DISCUSSION
NWS MIAMI FL
1227 PM EST TUE DEC 3 2013
.AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. LIGHT SOUTH TO
SOUTHEASTERLY WINDS WILL CONTINUE THIS AFTERNOON. THE SCT/BKN
STRATOCU CONTINUES TO HOLD ON AT 5-7KFT...SO KEPT IT IN FOR THE
AFTERNOON HOURS. MAINLY CLEAR SKIES ARE FORECAST FOR OVERNIGHT.
LIGHT AND VARIABLE WINDS TO A LIGHT LAND BREEZE FLOW IS EXPECTED
OVERNIGHT. SOUTHEAST WINDS ARE FORECAST TO INCREASE TO 5-10 KNOTS
BY LATE WEDNESDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 1026 AM EST TUE DEC 3 2013/
UPDATE...
PARTLY CLOUDY TO MOSTLY SUNNY SKIES PREVAIL ACROSS SOUTH FLORIDA
THIS MORNING. A FEW LIGHT SHOWERS ARE CURRENTLY SEEN ACROSS THE
GULF WATERS. LATEST HRRR DEPICTS THESE SHOWERS SPREADING ACROSS
PORTIONS OF THE INTERIOR THROUGH THE AFTERNOON. MADE MINOR TWEAKS
TO THE ONGOING FORECAST. UPDATE SENT.
PREV DISCUSSION... /ISSUED 554 AM EST TUE DEC 3 2013/
AVIATION...
HIGH PRESSURE WILL KEEP VFR CONDITIONS THROUGH THE TAF PERIOD,
WITH POSSIBLE BRIEF MVFR THIS MORNING DUE TO SOME LOWER CIGS.
HOWEVER, THERE IS A GREAT AMOUNT OF UNCERTAINTY WITH THIS, THUS
BEING LEFT OUT OF THE TAFS AT THIS TIME. THERE IS A MID LEVEL DECK
OF CLOUDS MOVING ACROSS SOUTH FLORIDA THIS MORNING. THIS HAS KEPT
FOG FROM FORMING AND IS EXPECTED TO REMAIN ABOVE 5000 FT.
SKIES SHOULD BEGIN TO CLEAR SOME LATER THIS MORNING, BECOMING A
SCT DECK. WINDS WILL PICK UP OUT OF THE SOUTHEAST BETWEEN 5 AND 10
KTS MID MORNING.
PREV DISCUSSION... /ISSUED 320 AM EST TUE DEC 3 2013/
DISCUSSION...
THE MAIN SURFACE FEATURES ACROSS THE REGION INCLUDE WEAK HIGH
PRESSURE ACROSS THE SOUTHEASTERN GULF THAT EXTENDS INTO SOUTH
FLORIDA AND A WEAK LOW OFF THE COAST OF THE CAROLINAS. THIS
SYNOPTIC SITUATION WILL MAINTAIN LIGHT WINDS ACROSS THE REGION
TODAY WHILE LOW LEVEL MOISTURE AND LOW LEVEL STRATUS CONTINUES TO
LINGER ACROSS THE REGION EARLY THIS MORNING. AT THE UPPER LEVELS A
TROUGH CONTINUES TO BUILD INTO THE WESTERN ATLANTIC TO THE EAST OF
THE SOUTHEASTERN STATES WHILE THE SOUTHERN EXTENT OF THE JET
STREAM IS POSITIONED ACROSS SOUTH FLORIDA AND THE FLORIDA STRAITS
EARLY THIS MORNING. RECENT WATER VAPOR IMAGERY INDICATES DRY MID
TO UPPER LEVEL AIR BUILDING ACROSS MOST OF THE FLORIDA PENINSULA
BUT MOISTURE CONTINUES ACROSS THE SOUTHERN HALF OF SOUTH FLORIDA.
FOR TODAY...GIVEN THE LINGERING MOISTURE IN THE GULF AND THE
AFOREMENTIONED JET STREAM PASSING ACROSS THE REGION THERE MAY BE A
SLIGHT CHANCE OF A FEW SHOWERS ACROSS THE GULF WATERS AND THE
NAPLES METRO AREA...BUT LOW CONFIDENCE AS THE MID TO UPPER LEVELS
WILL CONTINUE A DRYING TREND AS THE DAY CONTINUES. BUT THE
GUIDANCE INDICATES THAT THE LOW LEVEL MOISTURE AND ASSOCIATED
STRATUS WILL LIKELY LINGER ACROSS THE REGION TODAY.
FOR WEDNESDAY THROUGH FRIDAY...BY WEDNESDAY THE JET STREAM IS
FORECAST TO START LIFTING NORTH OF THE REGION WITH A MID TO UPPER
LEVEL RIDGE BUILDING WESTWARD AND SURFACE HIGH PRESSURE WILL BUILD
BACK INTO THE REGION FROM THE WESTERN ATLANTIC. WHILE LOW LEVEL
SOUTHERLY FLOW WILL MAINTAIN LOW LEVEL MOISTURE ACROSS THE
AREA...MAINLY STABLE WEATHER CONDITIONS ARE EXPECTED. HIGH
PRESSURE WILL CONTINUE TO BUILD WESTWARD ACROSS THE FLORIDA PENINSULA
THURSDAY AND FRIDAY WITH STABLE WEATHER CONDITIONS FORECAST TO
CONTINUE.
FOR THE UPCOMING WEEKEND...BY SATURDAY A COLD FRONT IS FORECAST TO
BECOME STATIONARY ACROSS THE SOUTHEAST U.S. WHILE HIGH PRESSURE
REMAINS IN PLACE ACROSS SOUTH FLORIDA AND ADJACENT WATERS WITH
MAINLY STABLE WEATHER FORECAST TO CONTINUE THROUGH THE WEEKEND.
THE EXTENDED GUIDANCE INDICATES THAT THE FRONT COULD ENTER CENTRAL
FLORIDA BY TUESDAY.
MARINE...
WINDS ARE FORECAST TO BE 10 KNOTS OR LESS THROUGH WEDNESDAY WITH
MAINLY TRANQUIL SEAS EXPECTED. BY THURSDAY THE PRESSURE GRADIENT
INCREASES ACROSS THE WESTERN ATLANTIC WITH EASTERLY FLOW IN THE 10
TO 15 KNOT RANGE FORECAST AND IS FORECAST TO PERSIST IN THAT RANGE
INTO THE UPCOMING WEEKEND WITH GULF STREAM SEAS FROM 2 TO 4 FEET
THROUGH THAT PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 66 81 69 81 / 10 0 10 -
FORT LAUDERDALE 68 81 72 82 / 10 0 - -
MIAMI 68 81 71 82 / 10 0 - -
NAPLES 64 82 65 85 / 10 - 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
253 PM EST TUE DEC 3 2013
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
WARM FRONT SHOULD BE MOVING NORTH THROUGH THE CWA THIS EVENING AND
OVERNIGHT. GFS/NAM KEEP ENHANCED MOISTURE ACROSS THE CWA THROUGH
WEDNESDAY MORNING...AND HRRR IS INDICATING AN EXPANSION OF THE RAIN
AREA AS IT MOVES NORTHEAST TONIGHT. HAVE KEPT LIKELY POPS OVER MUCH
OF THE CENTRAL TO NE ZONES WITH A GRADUAL DECREASE AFTER 06Z. SOME
LINGERING LOW POPS WEDNESDAY MORNING MAINLY NORTH. WEAK UPPER RIDGE
BUILDS OVER THE CWA WEDNESDAY AFTERNOON AND SO HAVE REMOVED THE POPS
FOR THAT TIME. STRONG SOUTHERLY FLOW WILL BRING ANOTHER INCREASE IN
MOISTURE TO THE CWA LATE WEDNESDAY NIGHT AHEAD OF AN APPROACHING
COLD FRONT. HAVE INTRODUCED POPS AGAIN TOWARD THURSDAY MORNING. AIR
MASS LOOKS STABLE FOR THE SHORT TERM...SO HAVE NO MENTION OF
THUNDER. INSTABILITY STARTS TO INCREASE BY 12Z THURSDAY. EXPECT WARM
TEMPERATURES WITH THE STRONG SOUTHERLY FLOW. OVERNIGHT MINS MAY
APPROACH RECORD VALUES.
41
.LONG TERM /THURSDAY THROUGH TUESDAY/...
ONLY MINOR CHANGES MADE TO THE EXTENDED WITH THIS PACKAGE. REFINED
TIMING OF POPS FOR EARLY THURSDAY AND MADE SOME MINOR ADJUSTMENTS
MAINLY TO LOW TEMPS THROUGH THE EXTENDED. GUIDANCE COMING INTO
SLIGHTLY BETTER AGREEMENT FOR THE FINAL FROPA AFTER THE WEEKEND
CAD EVENT /GFS COMING MUCH BETTER IN LINE WITH THE ECMWF/ SO MADE
SOME ADDITIONAL ADJUSTMENTS TO TEMPS EARLY NEXT WEEK...BUT OVERALL
VERY LITTLE CHANGE. STILL SOME CONCERN ABOUT THUNDERSTORMS
THURSDAY AND FRIDAY AFTERNOON...WITH INCREASING CONCERN FOR
ISOLATED SEVERE. SHERB VALUES HOVER JUST BELOW THE CRITICAL
THRESHOLD OF 1 FOR HIGH SHEAR LOW CAPE SEVERE WEATHER BOTH
AFTERNOONS AND SPC HAS ADDED A GENERAL THUNDER AREA FOR DAY 3
/THURSDAY/. WILL CONTINUE TO MONITOR EVOLUTION OF THE FORECAST.
TDP
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED AT 405 AM EST TUE DEC 3 2013/
AN UNSETTLED WEATHER PATTERN WILL PREDOMINATE FOR MUCH OF THE
EXTENDED PERIOD.
CHANCES FOR LIGHT RAIN WEDNESDAY NIGHT INCREASING OVER MAINLY N GA
AS AN INCREASINGLY WARM AND MOIST SOUTHERLY LOW LEVEL FLOW
CONTINUES AHEAD OF A SLOW MOVING COLD FRONT MOVING ACROSS THE MID
U.S.
THE GFS AND EUROPEAN ARE SIMILAR WITH BRINGING THE FRONT TO THE TN
VALLEY LATE THURSDAY WITH SHOWERS LIKELY FOR N AND PORTIONS OF
CENTRAL GA WITH SMALL CHANCES FOR THUNDERSTORMS. MUCAPE FORECAST IN
THE 200-600 RANGE. FOR THE MOST PART PRECIP EXPECTED TO BE LIGHT AND
POSSIBLY BRIEFLY MODERATE.
FRONT EXPECTED TO MOVE INTO N GA FRIDAY AND TO CENTRAL TO S GA LATE
SATURDAY. MAINLY SMALL THUNDERSTORM CHANCES ASSOCIATED AS AN AXIS OF
MUCAPE MOVES WITH THE FRONT INTO FRIDAY NIGHT BEFORE WEAKENING.
HIGHEST POPS EXPECTED TO BE OVER N GA FRIDAY/FRIDAY NIGHT. SATURDAY
POPS FOR CENTRAL GA MAY NOT BE HIGH ENOUGH WITH CHANCE SHOWERS
FORECAST.
THE TREND FOR MUCH WARMER TEMPERATURES WILL CONTINUE UNTIL THE FRONT
PASSES BY. EXPECTING NEAR-RECORD OR RECORD WARM MIN TEMPS FOR
FRIDAY MORNING.
WITH HIGH PRESSURE MOVING ACROSS THE NORTHERN STATES SATURDAY NIGHT
AND SUNDAY...GFS AND EUROPEAN ARE SIMILAR WITH FORECASTING A COLD
AIR DAMMING EVENT THAT WILL INCREASE RAIN CHANCES ACROSS N AND
PORTIONS OF CENTRAL GA. BY LATE DAY SUNDAY THE GFS AND EUROPEAN
BEGIN TO DIFFER THAT BECOMES EVEN GREATER THROUGH MONDAY. THE GFS
MOVES ANOTHER FRONT ACROSS THE AREA MONDAY DRYING THINGS OUT BY DAYS
END. THE EUROPEAN IS MUCH SLOWER WITH THE FRONT OVER NW GA AT DAYS
END MONDAY MAKING THE FORECAST HIGH UNCERTAIN.
BDL
&&
.AVIATION...
18Z UPDATE...
IFR CEILINGS SHOULD PREVAIL ACROSS THE TAF SITES THROUGH MOST OF THE
AFTERNOON AND INTO THE EVENING. HOWEVER...THERE WILL BE PERIODS OF
MVFR. RAIN SHOULD REDEVELOP AND SPREAD NORTHEAST LATE AFTERNOON AND
EVENING BEFORE DIMINISHING LATER TONIGHT. LIFR DEVELOPING ACROSS THE
TAF SITES AFTER 06Z...GRADUALLY IMPROVING AFTER 15Z WEDNESDAY. WINDS
LIGHT SOUTHEAST OVERNIGHT BECOMING SOUTH TO SOUTHWEST AFTER 12Z.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON ALL ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 52 68 57 72 / 70 20 20 40
ATLANTA 55 69 62 72 / 60 20 20 50
BLAIRSVILLE 49 63 57 67 / 50 20 30 60
CARTERSVILLE 52 68 60 72 / 50 20 30 50
COLUMBUS 57 75 65 76 / 60 10 20 40
GAINESVILLE 50 65 59 69 / 60 20 30 50
MACON 55 74 61 75 / 70 10 20 30
ROME 53 69 61 73 / 50 20 40 60
PEACHTREE CITY 51 70 60 73 / 70 10 20 50
VIDALIA 57 76 59 76 / 40 10 10 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41
LONG TERM....TDP
AVIATION...41
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
228 PM CST TUE DEC 3 2013
.DISCUSSION...
1055 AM CST
HAVE EXTENDED THE DENSE FOG ADVISORY A COUPLE HOURS ACROSS NORTH
CENTRAL IL AS WELL AS EXPAND IT EASTWARD INTO THE FAR WESTERN
CHICAGO SUBURBS. ALSO HAVE BUMPED DOWN HIGH TEMPERATURES SEVERAL
DEGREES GIVEN THE LIMITED WARM ADVECTION NOT BEING ABLE TO OFFSET
NULL SOLAR HEATING.
OBSERVED VISIBILITY AND WEBCAMS ACROSS MUCH OF NORTH CENTRAL AND
NORTHWEST IL INDICATE LITTLE IMPROVEMENT HAS OCCURRED WITH T/TD
SPREADS ALMOST ENTIRELY AT 1F OR LESS. WITH TEMPERATURES STILL
AROUND 40 AND QUITE A WAYS FROM THAT 48-50 NEEDED ON THE 12Z DVN
RAOB TO BREAK THROUGH INTO BETTER MIXING...NOT EXPECTING RAPID
IMPROVEMENT. HIGH RES MODELS AND ENSEMBLES SUCH AS THE HRRR AND
NARRE-TL INDICATE SLIGHT VISIBILITY IMPROVEMENT THIS
AFTERNOON...WHILE ALSO BOTH INDICATING SUSCEPTIBILITY TO DROPPING
RIGHT BACK INTO DENSE FOG AFTER DARK WHICH CONCEPTUALLY MAKES
SENSE WITH THE AREA ALONG/NORTH OF THE WARM FRONT. HOW QUICKLY THE
WARM FRONT PROGRESSES NORTHWARD TONIGHT IS HIGHLY UNCERTAIN AND
SOMETHING MODELS MAY PROGRESS TOO QUICKLY. HAVE FOR THE TIME BEING
ADDED AREAS OF FOG MENTION ACROSS THE CWA.
INTERMITTENT LIGHT RAIN/DRIZZLE SHOULD CONTINUE WITH ANOTHER
SMALL SCALE MID-LEVEL IMPULSE HELPING TO BRING A BIT OF ENHANCED
WARM AIR ADVECTION/ISENTROPIC ASCENT AND JUST SOME BROAD AND WEAK
OMEGA.
TEMPERATURES WILL OOZE UPWARD AND MAY REACH THEIR MAXS TOWARD 4-5
PM...ABOUT 1-2 HRS LATER THAN TYPICAL THIS TIME OF YEAR.
TEMPERATURES SHOULD BASICALLY HOLD STEADY INTO THE EVE AND MAY
CLIMB LATER INTO THE NIGHT.
MTF
//PREV DISCUSSION...
330 AM CST
FORECAST FOCUS REMAINS LARGELY ON THE NEAR TERM THIS MORNING...
NAMELY PRECIPITATION AND TEMPERATURE TRENDS TODAY THROUGH WEDNESDAY
AS DEEP LOW PRESSURE SYSTEM DEVELOPS IN RESPONSE TO AMPLIFICATION OF
UPPER TROUGH ACROSS THE WESTERN/CENTRAL CONUS. DAYS 3-7 CONTINUE TO
FEATURE MUCH COLDER THAN AVERAGE TEMPERATURES...WITH THE POTENTIAL
FOR A COUPLE OF LIGHT SNOW EVENTS MAINLY ACROSS THE FAR SOUTHEAST
LATE THURSDAY-FRIDAY...AND FOR MOST OF THE AREA SUNDAY/SUNDAY NIGHT.
00Z RAOB ANALYSIS INDICATES FAIRLY ZONAL FLOW PATTERN ACROSS THE
CENTRAL CONUS...WITH A DEEP SHORT WAVE TROUGH DIGGING SOUTHEAST
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SEVERAL RELATIVELY MINOR
AMPLITUDE SHORT WAVES WERE NOTED DOWNSTREAM ACROSS THE MIDWEST...
EMANATING FROM STRONG JET STREAK DEVELOPS AROUND THE SOUTHERN
PERIPHERY OF THE DIGGING TROUGH. ONE SUCH WAVE WAS NOTED IN WATER
VAPOR IMAGERY OVER THE UPPER MISSISSIPPI VALLEY EARLY THIS
MORNING...WHICH WAS RESPONSIBLE FOR AN AREA OF WARM ADVECTION
PRECIPITATION THAT MOVED ACROSS THE FORECAST AREA OVERNIGHT AND WAS
NOW EAST OF THE REGION. A COUPLE OF MORE SUBTLE MID-LEVEL WAVES WERE
NOTED IN THE SATELLITE IMAGERY...ONE APPROACHING QUICKLY FROM
EASTERN IA...AND THE OTHER UPSTREAM ACROSS WESTERN NEBRASKA. THESE
FEATURES WILL RIPPLE QUICKLY EAST ACROSS THE AREA TODAY...MAINLY
WORKING TO MAINTAIN SOUTHERLY FLOW AND CONTINUED WARM ADVECTION INTO
THE MIDWEST. WHILE SOME SPOTTY LIGHT RAIN IS POSSIBLE WITH ANY OF
THESE SUBTLE FEATURES...UPSTREAM SOUNDINGS FROM OMA/TOP/SGF INDICATE
FAIRLY DRY MID-LEVELS. FORECAST SOUNDINGS MAINTAIN THIS DRY LAYER
ROUGHLY BETWEEN 850-650 MB WHICH SUGGESTS MAINLY SCATTERED LIGHT
RAIN OR SOME DRIZZLE WITH ONLY LIGHT QPF AMOUNTS TODAY-TONIGHT AS
FORCING WITH THESE WAVES ACT ON MOIST LOW LEVELS OR BRIEF POCKETS OF
ENHANCED MID-LEVEL MOISTURE.
WITH ONGOING WARM ADVECTION...SURFACE TEMPERATURES AND DEW POINTS
WILL CONTINUE TO SLOWLY RISE AS A WARM FRONT CURRENTLY LIFTING INTO
CENTRAL ILLINOIS MOVES NORTH. WHILE THE BOUNDARY REMAINS A BIT
DIFFUSE EARLY THIS MORNING...THE FRONT SHOULD SHARPEN AND BEGIN TO
MOVE FASTER LATER TODAY AND TONIGHT AS SURFACE LOW PRESSURE DEEPENS
TO OUR WEST ACROSS THE CENTRAL PLAINS IN RESPONSE TO HEIGHT FALLS
WITH DEEPENING WESTERN TROUGH. MODELS ARE IN FAIRLY GOOD AGREEMENT
THAT THE SURFACE WARM FRONT SHOULD LIFT INTO NORTHERN IL BY LATE
AFTERNOON...WITH THE SOUTHERN AND CENTRAL PARTS OF THE CWA GETTING
INTO THE WARM SECTOR. TEMPS SHOULD REACH THE LOW-MID 50S ALONG AND
SOUTH OF I-80 THIS AFTERNOON...WITH 40S TO THE NORTH. IT WILL REMAIN
VERY MILD TONIGHT AS THE WARM FRONT REACHES THE IL/WI BORDER...WITH
OVERNIGHT LOWS HOLDING IN THE 40S ACROSS THE CWA.
GUIDANCE REMAINS IN TWO SEPARATE CAMPS WITH THE HANDLING OF THE MAIN
SURFACE LOW AND COLD FRONT ON WEDNESDAY...WITH THE DOMESTIC MODELS
REMAINING FASTER AND INITIALLY DEEPER BEYOND 30 HOURS THAN THE UK/EC
AND CANADIAN COUNTERPARTS. THE 00Z RUNS OF THE GFS AND TO A GREATER
EXTENT THE WRF HAVE SLOWED HOWEVER...WHICH LENDS SUPPORT TO OUR
FAVORING THE SLOWER SOLUTION OF THE UKMET/ECMWF AND GEM. THUS
CONTINUE TO FAVOR THE SCENARIO OF THE SURFACE LOW LIFTING ACROSS
EASTERN IOWA INTO WI WEDNESDAY AFTERNOON...AND THE TRAILING COLD
FRONT MOVING ACROSS THE WFO LOT FORECAST AREA FAIRLY LATE IN THE
AFTERNOON AND EVENING HOURS. THIS SUPPORTS TEMPS IN THE 50S...AND
EVEN A COUPLE OF 60S FAR SOUTH...WEDNESDAY WITH THE CWA STILL IN THE
WARM SECTOR AHEAD OF THE FRONT. MID-LEVEL MOISTURE CONTINUES TO BE
LIMITED...AND ALTHOUGH LIGHT RAIN/SHOWER CHANCES DO INCREASE WITH
THE APPROACH OF THE LOW/COLD FRONT THE BEST COVERAGE AND RAINFALL
AMOUNTS EXPECTED NORTH OF THE AREA ACROSS WI AND THE NORTHERN LAKES.
THE COLD FRONT PUSHES ACROSS THE AREA WEDNESDAY EVENING...SHUTTING
OFF PRECIP AS MID/UPPER LEVELS DRY OUT. THANKS TO WEST-SOUTHWEST
FLOW ALOFT THE FIRST PUSH OF COLDER AIR IS RELATIVELY WEAK...AS THE
FRONT AND LOW LEVEL BAROCLINIC ZONE SLOW UP FROM THE OHIO VALLEY TO
THE EASTERN LAKES INTO THURSDAY. A COUPLE OF DISTURBANCES RIPPLE
NORTHEAST ALONG THIS BAROCLINIC ZONE LATE THURSDAY INTO FRIDAY...
WITH THE POTENTIAL FOR SOME LIGHT SNOW FROM CENTRAL IL INTO NORTHERN
INDIANA AND MAINLY CLIPPING THE FAR SOUTHEAST PART OF THE CWA. A
SECOND PUSH OF COLDER AIR THEN SPREADS IN THURSDAY NIGHT-FRIDAY AS
THE UPPER LOW PASSES TO THE NORTH AND HEADS INTO EASTERN CANADA.
THIS ALLOWS 850 MB AIR OF -10 TO -15 C ACROSS THE AREA AND TEMPS A
GOOD 8-10F COLDER FRIDAY THAN ON THURSDAY. SOME DIFFERENCES REMAIN
WITH MODEL DETAILS AT THIS TIME...BUT CONTINUE TO FAVOR THE SIMILAR
GEM/ECMWF WHICH SUPPORTS HIGHS ONLY NEAR/AROUND 20 FRIDAY AND
SATURDAY AS ARCTIC HIGH PRESSURE BUILDS ACROSS THE MIDWEST. LOOKS
LIKE AT LEAST SOME SLIGHT MODERATION SUNDAY-MONDAY AS UPPER TROUGH
AMPLIFIES ACROSS THE WESTERN CONUS/NOAM...WITH AN AREA OF LOW
PRESSURE LIFTING ACROSS THE AREA SUNDAY WITH THE POTENTIAL FOR SOME
LIGHT SNOW.
RATZER
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* IFR/LIFR CIGS/VIS LOWERING TO LIFR/VLIFR THIS EVENING/TONIGHT.
* SOUTHEASTERLY WINDS AROUND 10 KT THROUGH EARLY EVENING.
* FOG WITH 1/2SM OVERNIGHT INTO WEDNESDAY MORNING.
* CHANCE OF SHOWERS WEDNESDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER THE SOUTH CENTRAL PLAINS WILL LIFT NORTHEAST
OVER MISSOURI WEDNESDAY MORNING...THEN MOVE NORTHEAST ACROSS
EASTERN IOWA AND NORTHWEST IL EARLY WEDNESDAY AFTERNOON. A WARM
FRONT EXTENDING EAST FROM THIS LOW...CURRENTLY ACROSS CENTRAL IL...
IS EXPECTED TO LIFT NORTH ACROSS THE TERMINALS OVERNIGHT INTO
WEDNESDAY MORNING. HOWEVER...CONFIDENCE REGARDING ITS SPEED AND
LOCATION IS LOW AND THIS CREATES A CHALLENGING FORECAST FOR FOG
POTENTIAL THIS EVENING THROUGH WEDNESDAY MORNING. PREVAILING
VISIBILITIES HAVE REMAINED IN THE 1-2SM WITH RFD NOW SLOWING
APPROACHING 1SM. WITH THE WARM FRONT EXPECTED TO REMAIN SOUTH OF
THE TERMINALS THROUGH AT LEAST THIS EVENING...EXPECT THE VIS TO
LOWER BACK UNDER 1SM THIS EVENING WITH SOME DRIZZLE POSSIBLE. THE
VIS MAY CONTINUE TO LOWER TO 1/2SM OR A 1/4SM AT SOME LOCATIONS...
ESPECIALLY AT RFD. IF THE WARM FRONT IS ABLE TO MOVE ACROSS
NORTHERN IL TONIGHT...VISIBILITIES WILL LIKELY IMPROVE INTO THE
1-2SM RANGE OR BETTER. HOWEVER...ITS POSSIBLE THE FRONT WILL SLOW
OR STALL AND IF THIS OCCURS...VISIBILITIES WILL LIKELY TANK
OVERNIGHT AND PERSIST INTO WEDNESDAY MORNING...WHEN THE WARM FRONT
WILL FINALLY MOVE ACROSS THE AREA.
WIND DIRECTIONS WILL REMAIN SOUTHEASTERLY AROUND 10KTS THIS
AFTERNOON...THEN DIMINISH THIS EVENING. SPECIFIC DIRECTIONS
TONIGHT INTO WEDNESDAY MORNING WILL DEPEND ON THE WARM FRONT
MOVEMENT/TIMING...LIKELY REMAINING MORE SOUTHEAST OR EVEN EAST/
SOUTHEAST NORTH OF THE FRONT WITH SOUTHERLY WINDS SOUTH OF THE
FRONT. CMS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH FOR CIG/VIS TRENDS INTO THIS EVENING.
* MEDIUM FOR CIG/VIS TRENDS OVERNIGHT AND WEDNESDAY MORNING.
* MEDIUM FOR WIND SPEEDS/DIRECTIONS THROUGH THE PERIOD.
* LOW FOR SHOWERS WEDNESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* IFR/LIFR CIGS/VIS LOWERING TO LIFR/VLIFR THIS EVENING/TONIGHT.
* SOUTHEASTERLY WINDS AROUND 10 KT THROUGH EARLY EVENING.
* FOG WITH 1/2SM OVERNIGHT INTO WEDNESDAY MORNING.
* CHANCE OF SHOWERS WEDNESDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER THE SOUTH CENTRAL PLAINS WILL LIFT NORTHEAST
OVER MISSOURI WEDNESDAY MORNING...THEN MOVE NORTHEAST ACROSS
EASTERN IOWA AND NORTHWEST IL EARLY WEDNESDAY AFTERNOON. A WARM
FRONT EXTENDING EAST FROM THIS LOW...CURRENTLY ACROSS CENTRAL IL...
IS EXPECTED TO LIFT NORTH ACROSS THE TERMINALS OVERNIGHT INTO
WEDNESDAY MORNING. HOWEVER...CONFIDENCE REGARDING ITS SPEED AND
LOCATION IS LOW AND THIS CREATES A CHALLENGING FORECAST FOR FOG
POTENTIAL THIS EVENING THROUGH WEDNESDAY MORNING. PREVAILING
VISIBILITIES HAVE REMAINED IN THE 1-2SM WITH RFD NOW SLOWING
APPROACHING 1SM. WITH THE WARM FRONT EXPECTED TO REMAIN SOUTH OF
THE TERMINALS THROUGH AT LEAST THIS EVENING...EXPECT THE VIS TO
LOWER BACK UNDER 1SM THIS EVENING WITH SOME DRIZZLE POSSIBLE. THE
VIS MAY CONTINUE TO LOWER TO 1/2SM OR A 1/4SM AT SOME LOCATIONS...
ESPECIALLY AT RFD. IF THE WARM FRONT IS ABLE TO MOVE ACROSS
NORTHERN IL TONIGHT...VISIBILITIES WILL LIKELY IMPROVE INTO THE
1-2SM RANGE OR BETTER. HOWEVER...ITS POSSIBLE THE FRONT WILL SLOW
OR STALL AND IF THIS OCCURS...VISIBILITIES WILL LIKELY TANK
OVERNIGHT AND PERSIST INTO WEDNESDAY MORNING...WHEN THE WARM FRONT
WILL FINALLY MOVE ACROSS THE AREA.
WIND DIRECTIONS WILL REMAIN SOUTHEASTERLY AROUND 10KTS THIS
AFTERNOON...THEN DIMINISH THIS EVENING. SPECIFIC DIRECTIONS
TONIGHT INTO WEDNESDAY MORNING WILL DEPEND ON THE WARM FRONT
MOVEMENT/TIMING...LIKELY REMAINING MORE SOUTHEAST OR EVEN EAST/
SOUTHEAST NORTH OF THE FRONT WITH SOUTHERLY WINDS SOUTH OF THE
FRONT. CMS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH FOR CIG/VIS TRENDS INTO THIS EVENING.
* MEDIUM FOR CIG/VIS TRENDS OVERNIGHT AND WEDNESDAY MORNING.
* MEDIUM FOR WIND SPEEDS/DIRECTIONS THROUGH THE PERIOD.
* LOW FOR SHOWERS WEDNESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.MARINE...
228 PM CST
EASTERLY FLOW WILL CONTINUE OVER THE LAKE TONIGHT AND GRADUALLY VEER
TO SOUTH DURING WEDNESDAY. THIS WILL CONTINUE TO BRING ANOMALOUSLY
HIGH MOISTURE FOR THIS TIME OF YEAR OVER WHAT IS COOLER WATER...SO
EXPECTING DENSE FOG TO BLOSSOM THROUGH THIS EVENING AND PERSIST INTO
WEDNESDAY. AS THE LOW PRESSURE LIFTS UP TO LAKE SUPERIOR BY
WEDNESDAY EVENING IT WILL SWING A COLD FRONT ACROSS THE LAKE WHICH
WILL INTRODUCE STOUT COLD AIR ADVECTION. THE STEEPENED LAPSE RATES
AND ENHANCED MIXING WILL BRING A PERIOD OF AT LEAST GALE FORCE GUSTS
TO THE OPEN WATER. THESE ARE MOST FAVORED DURING THE DAY THURSDAY
BUT COULD BEGIN LATE WEDNESDAY NIGHT. THROUGHOUT THAT TIME SMALL
CRAFT ADVISORY CRITERIA SHOULD BE REACHED IN THE ILLINOIS AND
INDIANA NEARSHORE ZONES. THIS PATTERN SHIFT WILL BEGIN A PROLONGED
PERIOD OF WEST TO NORTHWEST FLOW OVER THE LAKE INTO THE WEEKEND AS
THE COLD AIR CONTINUES TO RE-ENFORCE ITSELF.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012 UNTIL 10 AM WEDNESDAY.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
216 PM CST TUE DEC 3 2013
.DISCUSSION...
1055 AM CST
HAVE EXTENDED THE DENSE FOG ADVISORY A COUPLE HOURS ACROSS NORTH
CENTRAL IL AS WELL AS EXPAND IT EASTWARD INTO THE FAR WESTERN
CHICAGO SUBURBS. ALSO HAVE BUMPED DOWN HIGH TEMPERATURES SEVERAL
DEGREES GIVEN THE LIMITED WARM ADVECTION NOT BEING ABLE TO OFFSET
NULL SOLAR HEATING.
OBSERVED VISIBILITY AND WEBCAMS ACROSS MUCH OF NORTH CENTRAL AND
NORTHWEST IL INDICATE LITTLE IMPROVEMENT HAS OCCURRED WITH T/TD
SPREADS ALMOST ENTIRELY AT 1F OR LESS. WITH TEMPERATURES STILL
AROUND 40 AND QUITE A WAYS FROM THAT 48-50 NEEDED ON THE 12Z DVN
RAOB TO BREAK THROUGH INTO BETTER MIXING...NOT EXPECTING RAPID
IMPROVEMENT. HIGH RES MODELS AND ENSEMBLES SUCH AS THE HRRR AND
NARRE-TL INDICATE SLIGHT VISIBILITY IMPROVEMENT THIS
AFTERNOON...WHILE ALSO BOTH INDICATING SUSCEPTIBILITY TO DROPPING
RIGHT BACK INTO DENSE FOG AFTER DARK WHICH CONCEPTUALLY MAKES
SENSE WITH THE AREA ALONG/NORTH OF THE WARM FRONT. HOW QUICKLY THE
WARM FRONT PROGRESSES NORTHWARD TONIGHT IS HIGHLY UNCERTAIN AND
SOMETHING MODELS MAY PROGRESS TOO QUICKLY. HAVE FOR THE TIME BEING
ADDED AREAS OF FOG MENTION ACROSS THE CWA.
INTERMITTENT LIGHT RAIN/DRIZZLE SHOULD CONTINUE WITH ANOTHER
SMALL SCALE MID-LEVEL IMPULSE HELPING TO BRING A BIT OF ENHANCED
WARM AIR ADVECTION/ISENTROPIC ASCENT AND JUST SOME BROAD AND WEAK
OMEGA.
TEMPERATURES WILL OOZE UPWARD AND MAY REACH THEIR MAXS TOWARD 4-5
PM...ABOUT 1-2 HRS LATER THAN TYPICAL THIS TIME OF YEAR.
TEMPERATURES SHOULD BASICALLY HOLD STEADY INTO THE EVE AND MAY
CLIMB LATER INTO THE NIGHT.
MTF
//PREV DISCUSSION...
330 AM CST
FORECAST FOCUS REMAINS LARGELY ON THE NEAR TERM THIS MORNING...
NAMELY PRECIPITATION AND TEMPERATURE TRENDS TODAY THROUGH WEDNESDAY
AS DEEP LOW PRESSURE SYSTEM DEVELOPS IN RESPONSE TO AMPLIFICATION OF
UPPER TROUGH ACROSS THE WESTERN/CENTRAL CONUS. DAYS 3-7 CONTINUE TO
FEATURE MUCH COLDER THAN AVERAGE TEMPERATURES...WITH THE POTENTIAL
FOR A COUPLE OF LIGHT SNOW EVENTS MAINLY ACROSS THE FAR SOUTHEAST
LATE THURSDAY-FRIDAY...AND FOR MOST OF THE AREA SUNDAY/SUNDAY NIGHT.
00Z RAOB ANALYSIS INDICATES FAIRLY ZONAL FLOW PATTERN ACROSS THE
CENTRAL CONUS...WITH A DEEP SHORT WAVE TROUGH DIGGING SOUTHEAST
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SEVERAL RELATIVELY MINOR
AMPLITUDE SHORT WAVES WERE NOTED DOWNSTREAM ACROSS THE MIDWEST...
EMANATING FROM STRONG JET STREAK DEVELOPS AROUND THE SOUTHERN
PERIPHERY OF THE DIGGING TROUGH. ONE SUCH WAVE WAS NOTED IN WATER
VAPOR IMAGERY OVER THE UPPER MISSISSIPPI VALLEY EARLY THIS
MORNING...WHICH WAS RESPONSIBLE FOR AN AREA OF WARM ADVECTION
PRECIPITATION THAT MOVED ACROSS THE FORECAST AREA OVERNIGHT AND WAS
NOW EAST OF THE REGION. A COUPLE OF MORE SUBTLE MID-LEVEL WAVES WERE
NOTED IN THE SATELLITE IMAGERY...ONE APPROACHING QUICKLY FROM
EASTERN IA...AND THE OTHER UPSTREAM ACROSS WESTERN NEBRASKA. THESE
FEATURES WILL RIPPLE QUICKLY EAST ACROSS THE AREA TODAY...MAINLY
WORKING TO MAINTAIN SOUTHERLY FLOW AND CONTINUED WARM ADVECTION INTO
THE MIDWEST. WHILE SOME SPOTTY LIGHT RAIN IS POSSIBLE WITH ANY OF
THESE SUBTLE FEATURES...UPSTREAM SOUNDINGS FROM OMA/TOP/SGF INDICATE
FAIRLY DRY MID-LEVELS. FORECAST SOUNDINGS MAINTAIN THIS DRY LAYER
ROUGHLY BETWEEN 850-650 MB WHICH SUGGESTS MAINLY SCATTERED LIGHT
RAIN OR SOME DRIZZLE WITH ONLY LIGHT QPF AMOUNTS TODAY-TONIGHT AS
FORCING WITH THESE WAVES ACT ON MOIST LOW LEVELS OR BRIEF POCKETS OF
ENHANCED MID-LEVEL MOISTURE.
WITH ONGOING WARM ADVECTION...SURFACE TEMPERATURES AND DEW POINTS
WILL CONTINUE TO SLOWLY RISE AS A WARM FRONT CURRENTLY LIFTING INTO
CENTRAL ILLINOIS MOVES NORTH. WHILE THE BOUNDARY REMAINS A BIT
DIFFUSE EARLY THIS MORNING...THE FRONT SHOULD SHARPEN AND BEGIN TO
MOVE FASTER LATER TODAY AND TONIGHT AS SURFACE LOW PRESSURE DEEPENS
TO OUR WEST ACROSS THE CENTRAL PLAINS IN RESPONSE TO HEIGHT FALLS
WITH DEEPENING WESTERN TROUGH. MODELS ARE IN FAIRLY GOOD AGREEMENT
THAT THE SURFACE WARM FRONT SHOULD LIFT INTO NORTHERN IL BY LATE
AFTERNOON...WITH THE SOUTHERN AND CENTRAL PARTS OF THE CWA GETTING
INTO THE WARM SECTOR. TEMPS SHOULD REACH THE LOW-MID 50S ALONG AND
SOUTH OF I-80 THIS AFTERNOON...WITH 40S TO THE NORTH. IT WILL REMAIN
VERY MILD TONIGHT AS THE WARM FRONT REACHES THE IL/WI BORDER...WITH
OVERNIGHT LOWS HOLDING IN THE 40S ACROSS THE CWA.
GUIDANCE REMAINS IN TWO SEPARATE CAMPS WITH THE HANDLING OF THE MAIN
SURFACE LOW AND COLD FRONT ON WEDNESDAY...WITH THE DOMESTIC MODELS
REMAINING FASTER AND INITIALLY DEEPER BEYOND 30 HOURS THAN THE UK/EC
AND CANADIAN COUNTERPARTS. THE 00Z RUNS OF THE GFS AND TO A GREATER
EXTENT THE WRF HAVE SLOWED HOWEVER...WHICH LENDS SUPPORT TO OUR
FAVORING THE SLOWER SOLUTION OF THE UKMET/ECMWF AND GEM. THUS
CONTINUE TO FAVOR THE SCENARIO OF THE SURFACE LOW LIFTING ACROSS
EASTERN IOWA INTO WI WEDNESDAY AFTERNOON...AND THE TRAILING COLD
FRONT MOVING ACROSS THE WFO LOT FORECAST AREA FAIRLY LATE IN THE
AFTERNOON AND EVENING HOURS. THIS SUPPORTS TEMPS IN THE 50S...AND
EVEN A COUPLE OF 60S FAR SOUTH...WEDNESDAY WITH THE CWA STILL IN THE
WARM SECTOR AHEAD OF THE FRONT. MID-LEVEL MOISTURE CONTINUES TO BE
LIMITED...AND ALTHOUGH LIGHT RAIN/SHOWER CHANCES DO INCREASE WITH
THE APPROACH OF THE LOW/COLD FRONT THE BEST COVERAGE AND RAINFALL
AMOUNTS EXPECTED NORTH OF THE AREA ACROSS WI AND THE NORTHERN LAKES.
THE COLD FRONT PUSHES ACROSS THE AREA WEDNESDAY EVENING...SHUTTING
OFF PRECIP AS MID/UPPER LEVELS DRY OUT. THANKS TO WEST-SOUTHWEST
FLOW ALOFT THE FIRST PUSH OF COLDER AIR IS RELATIVELY WEAK...AS THE
FRONT AND LOW LEVEL BAROCLINIC ZONE SLOW UP FROM THE OHIO VALLEY TO
THE EASTERN LAKES INTO THURSDAY. A COUPLE OF DISTURBANCES RIPPLE
NORTHEAST ALONG THIS BAROCLINIC ZONE LATE THURSDAY INTO FRIDAY...
WITH THE POTENTIAL FOR SOME LIGHT SNOW FROM CENTRAL IL INTO NORTHERN
INDIANA AND MAINLY CLIPPING THE FAR SOUTHEAST PART OF THE CWA. A
SECOND PUSH OF COLDER AIR THEN SPREADS IN THURSDAY NIGHT-FRIDAY AS
THE UPPER LOW PASSES TO THE NORTH AND HEADS INTO EASTERN CANADA.
THIS ALLOWS 850 MB AIR OF -10 TO -15 C ACROSS THE AREA AND TEMPS A
GOOD 8-10F COLDER FRIDAY THAN ON THURSDAY. SOME DIFFERENCES REMAIN
WITH MODEL DETAILS AT THIS TIME...BUT CONTINUE TO FAVOR THE SIMILAR
GEM/ECMWF WHICH SUPPORTS HIGHS ONLY NEAR/AROUND 20 FRIDAY AND
SATURDAY AS ARCTIC HIGH PRESSURE BUILDS ACROSS THE MIDWEST. LOOKS
LIKE AT LEAST SOME SLIGHT MODERATION SUNDAY-MONDAY AS UPPER TROUGH
AMPLIFIES ACROSS THE WESTERN CONUS/NOAM...WITH AN AREA OF LOW
PRESSURE LIFTING ACROSS THE AREA SUNDAY WITH THE POTENTIAL FOR SOME
LIGHT SNOW.
RATZER
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* IFR/LIFR CIGS/VIS LOWERING TO LIFR/VLIFR THIS EVENING/TONIGHT.
* SOUTHEASTERLY WINDS AROUND 10 KT THROUGH EARLY EVENING.
* FOG WITH 1/2SM OVERNIGHT INTO WEDNESDAY MORNING.
* CHANCE OF SHOWERS WEDNESDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER THE SOUTH CENTRAL PLAINS WILL LIFT NORTHEAST
OVER MISSOURI WEDNESDAY MORNING...THEN MOVE NORTHEAST ACROSS
EASTERN IOWA AND NORTHWEST IL EARLY WEDNESDAY AFTERNOON. A WARM
FRONT EXTENDING EAST FROM THIS LOW...CURRENTLY ACROSS CENTRAL IL...
IS EXPECTED TO LIFT NORTH ACROSS THE TERMINALS OVERNIGHT INTO
WEDNESDAY MORNING. HOWEVER...CONFIDENCE REGARDING ITS SPEED AND
LOCATION IS LOW AND THIS CREATES A CHALLENGING FORECAST FOR FOG
POTENTIAL THIS EVENING THROUGH WEDNESDAY MORNING. PREVAILING
VISIBILITIES HAVE REMAINED IN THE 1-2SM WITH RFD NOW SLOWING
APPROACHING 1SM. WITH THE WARM FRONT EXPECTED TO REMAIN SOUTH OF
THE TERMINALS THROUGH AT LEAST THIS EVENING...EXPECT THE VIS TO
LOWER BACK UNDER 1SM THIS EVENING WITH SOME DRIZZLE POSSIBLE. THE
VIS MAY CONTINUE TO LOWER TO 1/2SM OR A 1/4SM AT SOME LOCATIONS...
ESPECIALLY AT RFD. IF THE WARM FRONT IS ABLE TO MOVE ACROSS
NORTHERN IL TONIGHT...VISIBILITIES WILL LIKELY IMPROVE INTO THE
1-2SM RANGE OR BETTER. HOWEVER...ITS POSSIBLE THE FRONT WILL SLOW
OR STALL AND IF THIS OCCURS...VISIBILITIES WILL LIKELY TANK
OVERNIGHT AND PERSIST INTO WEDNESDAY MORNING...WHEN THE WARM FRONT
WILL FINALLY MOVE ACROSS THE AREA.
WIND DIRECTIONS WILL REMAIN SOUTHEASTERLY AROUND 10KTS THIS
AFTERNOON...THEN DIMINISH THIS EVENING. SPECIFIC DIRECTIONS
TONIGHT INTO WEDNESDAY MORNING WILL DEPEND ON THE WARM FRONT
MOVEMENT/TIMING...LIKELY REMAINING MORE SOUTHEAST OR EVEN EAST/
SOUTHEAST NORTH OF THE FRONT WITH SOUTHERLY WINDS SOUTH OF THE
FRONT. CMS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH FOR CIG/VIS TRENDS INTO THIS EVENING.
* MEDIUM FOR CIG/VIS TRENDS OVERNIGHT AND WEDNESDAY MORNING.
* MEDIUM FOR WIND SPEEDS/DIRECTIONS THROUGH THE PERIOD.
* LOW FOR SHOWERS WEDNESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* IFR/LIFR CIGS/VIS LOWERING TO LIFR/VLIFR LATE THIS AFTERNOON/
EARLY EVENING.
* CHANCE OF LIGHT RAIN LATE THIS AFTERNOON/EARLY EVENING.
* SOUTHEASTERLY WINDS UP TO 10 KT THROUGH EARLY EVENING.
* FOG WITH 1/2SM OVERNIGHT INTO WEDNESDAY MORNING.
* CHANCE OF SHOWERS WEDNESDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER THE SOUTH CENTRAL PLAINS WILL LIFT NORTHEAST
OVER MISSOURI WEDNESDAY MORNING...THEN MOVE NORTHEAST ACROSS
EASTERN IOWA AND NORTHWEST IL EARLY WEDNESDAY AFTERNOON. A WARM
FRONT EXTENDING EAST FROM THIS LOW...CURRENTLY ACROSS CENTRAL IL...
IS EXPECTED TO LIFT NORTH ACROSS THE TERMINALS OVERNIGHT INTO
WEDNESDAY MORNING. HOWEVER...CONFIDENCE REGARDING ITS SPEED AND
LOCATION IS LOW AND THIS CREATES A CHALLENGING FORECAST FOR FOG
POTENTIAL THIS EVENING THROUGH WEDNESDAY MORNING. PREVAILING
VISIBILITIES HAVE REMAINED IN THE 1-2SM WITH RFD NOW SLOWING
APPROACHING 1SM. WITH THE WARM FRONT EXPECTED TO REMAIN SOUTH OF
THE TERMINALS THROUGH AT LEAST THIS EVENING...EXPECT THE VIS TO
LOWER BACK UNDER 1SM THIS EVENING WITH SOME DRIZZLE POSSIBLE. THE
VIS MAY CONTINUE TO LOWER TO 1/2SM OR A 1/4SM AT SOME LOCATIONS...
ESPECIALLY AT RFD. IF THE WARM FRONT IS ABLE TO MOVE ACROSS
NORTHERN IL TONIGHT...VISIBILITIES WILL LIKELY IMPROVE INTO THE
1-2SM RANGE OR BETTER. HOWEVER...ITS POSSIBLE THE FRONT WILL SLOW
OR STALL AND IF THIS OCCURS...VISIBILITIES WILL LIKELY TANK
OVERNIGHT AND PERSIST INTO WEDNESDAY MORNING...WHEN THE WARM FRONT
WILL FINALLY MOVE ACROSS THE AREA.
WIND DIRECTIONS WILL REMAIN SOUTHEASTERLY AROUND 10KTS THIS
AFTERNOON...THEN DIMINISH THIS EVENING. SPECIFIC DIRECTIONS
TONIGHT INTO WEDNESDAY MORNING WILL DEPEND ON THE WARM FRONT
MOVEMENT/TIMING...LIKELY REMAINING MORE SOUTHEAST OR EVEN EAST/
SOUTHEAST NORTH OF THE FRONT WITH SOUTHERLY WINDS SOUTH OF THE
FRONT. CMS
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH FOR CIG/VIS TRENDS INTO THIS EVENING.
* MEDIUM FOR LIGHT RAIN LATE THIS AFTERNOON/EARLY THIS EVENING.
* MEDIUM FOR CIG/VIS TRENDS OVERNIGHT AND WEDNESDAY MORNING.
* MEDIUM FOR WIND SPEEDS/DIRECTIONS THROUGH THE PERIOD.
* LOW FOR SHOWERS WEDNESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.MARINE...
239 AM CST
STILL SIGNIFICANT DIFFERENCES IN THE MODELS WITH RESPECT TO LOW
PRESSURE THAT IS EXPECTED TO IMPACT THE LAKES MIDWEEK. GUIDANCE HAS
TRENDED TOWARDS A SLOWER FRONTAL TIMING AND MORE NORTHERLY LOW TRACK
THOUGH...A TYPICAL TREND WHEN THE UPPER AIR PATTERN IS AMPLIFIED.
WITH THAT IN MIND...HAVE BASED FORECAST TIMING ON A BLEND OF THE GEM
AND THE ECWMF WHICH HAVE BEEN FAIRLY CONSISTENT WITH SLOWER TIMING
AND WHICH THE FASTER NCEP GUIDANCE SEEMS TO BE TRENDING TOWARDS. A
DEEPENING AREA OF LOW PRESSURE IS EXPECTED TO LIFT FROM THE CENTRAL
PLAINS TODAY AND TOMORROW...ACROSS LAKE SUPERIOR OR WEDNESDAY NIGHT.
MODERATE SOUTHEAST TO EAST WINDS ARE EXPECTED AHEAD OF THE
LOW...THOUGH STABLE CONDITIONS WILL HELP KEEP THE HIGHER END GUSTS
FROM REACHING THE LAKE SURFACE. BEHIND THE FRONT...STRONG AND COLD
HIGH PRESSURE WILL OVERSPREAD THE PLAINS WITH A TIGHT GRADIENT ONLY
VERY GRADUALLY SUBSIDING THROUGH THE REST OF THE WEEK. THERE MAY BE
A SHORT PERIOD OF WESTERLY GALES IMMEDIATELY BEHIND THE FRONT
WEDNESDAY NIGHT INTO THURSDAY...WITH 30KTS REST OF THURSDAY INTO
FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY
IS UNTIL 3 PM TUESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1138 AM CST TUE DEC 3 2013
.DISCUSSION...
1055 AM CST
HAVE EXTENDED THE DENSE FOG ADVISORY A COUPLE HOURS ACROSS NORTH
CENTRAL IL AS WELL AS EXPAND IT EASTWARD INTO THE FAR WESTERN
CHICAGO SUBURBS. ALSO HAVE BUMPED DOWN HIGH TEMPERATURES SEVERAL
DEGREES GIVEN THE LIMITED WARM ADVECTION NOT BEING ABLE TO OFFSET
NULL SOLAR HEATING.
OBSERVED VISIBILITY AND WEBCAMS ACROSS MUCH OF NORTH CENTRAL AND
NORTHWEST IL INDICATE LITTLE IMPROVEMENT HAS OCCURRED WITH T/TD
SPREADS ALMOST ENTIRELY AT 1F OR LESS. WITH TEMPERATURES STILL
AROUND 40 AND QUITE A WAYS FROM THAT 48-50 NEEDED ON THE 12Z DVN
RAOB TO BREAK THROUGH INTO BETTER MIXING...NOT EXPECTING RAPID
IMPROVEMENT. HIGH RES MODELS AND ENSEMBLES SUCH AS THE HRRR AND
NARRE-TL INDICATE SLIGHT VISIBILITY IMPROVEMENT THIS
AFTERNOON...WHILE ALSO BOTH INDICATING SUSCEPTIBILITY TO DROPPING
RIGHT BACK INTO DENSE FOG AFTER DARK WHICH CONCEPTUALLY MAKES
SENSE WITH THE AREA ALONG/NORTH OF THE WARM FRONT. HOW QUICKLY THE
WARM FRONT PROGRESSES NORTHWARD TONIGHT IS HIGHLY UNCERTAIN AND
SOMETHING MODELS MAY PROGRESS TOO QUICKLY. HAVE FOR THE TIME BEING
ADDED AREAS OF FOG MENTION ACROSS THE CWA.
INTERMITTENT LIGHT RAIN/DRIZZLE SHOULD CONTINUE WITH ANOTHER
SMALL SCALE MID-LEVEL IMPULSE HELPING TO BRING A BIT OF ENHANCED
WARM AIR ADVECTION/ISENTROPIC ASCENT AND JUST SOME BROAD AND WEAK
OMEGA.
TEMPERATURES WILL OOZE UPWARD AND MAY REACH THEIR MAXS TOWARD 4-5
PM...ABOUT 1-2 HRS LATER THAN TYPICAL THIS TIME OF YEAR.
TEMPERATURES SHOULD BASICALLY HOLD STEADY INTO THE EVE AND MAY
CLIMB LATER INTO THE NIGHT.
MTF
&&
.PREV DISCUSSION...
330 AM CST
FORECAST FOCUS REMAINS LARGELY ON THE NEAR TERM THIS MORNING...
NAMELY PRECIPITATION AND TEMPERATURE TRENDS TODAY THROUGH WEDNESDAY
AS DEEP LOW PRESSURE SYSTEM DEVELOPS IN RESPONSE TO AMPLIFICATION OF
UPPER TROUGH ACROSS THE WESTERN/CENTRAL CONUS. DAYS 3-7 CONTINUE TO
FEATURE MUCH COLDER THAN AVERAGE TEMPERATURES...WITH THE POTENTIAL
FOR A COUPLE OF LIGHT SNOW EVENTS MAINLY ACROSS THE FAR SOUTHEAST
LATE THURSDAY-FRIDAY...AND FOR MOST OF THE AREA SUNDAY/SUNDAY NIGHT.
00Z RAOB ANALYSIS INDICATES FAIRLY ZONAL FLOW PATTERN ACROSS THE
CENTRAL CONUS...WITH A DEEP SHORT WAVE TROUGH DIGGING SOUTHEAST
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SEVERAL RELATIVELY MINOR
AMPLITUDE SHORT WAVES WERE NOTED DOWNSTREAM ACROSS THE MIDWEST...
EMANATING FROM STRONG JET STREAK DEVELOPS AROUND THE SOUTHERN
PERIPHERY OF THE DIGGING TROUGH. ONE SUCH WAVE WAS NOTED IN WATER
VAPOR IMAGERY OVER THE UPPER MISSISSIPPI VALLEY EARLY THIS
MORNING...WHICH WAS RESPONSIBLE FOR AN AREA OF WARM ADVECTION
PRECIPITATION THAT MOVED ACROSS THE FORECAST AREA OVERNIGHT AND WAS
NOW EAST OF THE REGION. A COUPLE OF MORE SUBTLE MID-LEVEL WAVES WERE
NOTED IN THE SATELLITE IMAGERY...ONE APPROACHING QUICKLY FROM
EASTERN IA...AND THE OTHER UPSTREAM ACROSS WESTERN NEBRASKA. THESE
FEATURES WILL RIPPLE QUICKLY EAST ACROSS THE AREA TODAY...MAINLY
WORKING TO MAINTAIN SOUTHERLY FLOW AND CONTINUED WARM ADVECTION INTO
THE MIDWEST. WHILE SOME SPOTTY LIGHT RAIN IS POSSIBLE WITH ANY OF
THESE SUBTLE FEATURES...UPSTREAM SOUNDINGS FROM OMA/TOP/SGF INDICATE
FAIRLY DRY MID-LEVELS. FORECAST SOUNDINGS MAINTAIN THIS DRY LAYER
ROUGHLY BETWEEN 850-650 MB WHICH SUGGESTS MAINLY SCATTERED LIGHT
RAIN OR SOME DRIZZLE WITH ONLY LIGHT QPF AMOUNTS TODAY-TONIGHT AS
FORCING WITH THESE WAVES ACT ON MOIST LOW LEVELS OR BRIEF POCKETS OF
ENHANCED MID-LEVEL MOISTURE.
WITH ONGOING WARM ADVECTION...SURFACE TEMPERATURES AND DEW POINTS
WILL CONTINUE TO SLOWLY RISE AS A WARM FRONT CURRENTLY LIFTING INTO
CENTRAL ILLINOIS MOVES NORTH. WHILE THE BOUNDARY REMAINS A BIT
DIFFUSE EARLY THIS MORNING...THE FRONT SHOULD SHARPEN AND BEGIN TO
MOVE FASTER LATER TODAY AND TONIGHT AS SURFACE LOW PRESSURE DEEPENS
TO OUR WEST ACROSS THE CENTRAL PLAINS IN RESPONSE TO HEIGHT FALLS
WITH DEEPENING WESTERN TROUGH. MODELS ARE IN FAIRLY GOOD AGREEMENT
THAT THE SURFACE WARM FRONT SHOULD LIFT INTO NORTHERN IL BY LATE
AFTERNOON...WITH THE SOUTHERN AND CENTRAL PARTS OF THE CWA GETTING
INTO THE WARM SECTOR. TEMPS SHOULD REACH THE LOW-MID 50S ALONG AND
SOUTH OF I-80 THIS AFTERNOON...WITH 40S TO THE NORTH. IT WILL REMAIN
VERY MILD TONIGHT AS THE WARM FRONT REACHES THE IL/WI BORDER...WITH
OVERNIGHT LOWS HOLDING IN THE 40S ACROSS THE CWA.
GUIDANCE REMAINS IN TWO SEPARATE CAMPS WITH THE HANDLING OF THE MAIN
SURFACE LOW AND COLD FRONT ON WEDNESDAY...WITH THE DOMESTIC MODELS
REMAINING FASTER AND INITIALLY DEEPER BEYOND 30 HOURS THAN THE UK/EC
AND CANADIAN COUNTERPARTS. THE 00Z RUNS OF THE GFS AND TO A GREATER
EXTENT THE WRF HAVE SLOWED HOWEVER...WHICH LENDS SUPPORT TO OUR
FAVORING THE SLOWER SOLUTION OF THE UKMET/ECMWF AND GEM. THUS
CONTINUE TO FAVOR THE SCENARIO OF THE SURFACE LOW LIFTING ACROSS
EASTERN IOWA INTO WI WEDNESDAY AFTERNOON...AND THE TRAILING COLD
FRONT MOVING ACROSS THE WFO LOT FORECAST AREA FAIRLY LATE IN THE
AFTERNOON AND EVENING HOURS. THIS SUPPORTS TEMPS IN THE 50S...AND
EVEN A COUPLE OF 60S FAR SOUTH...WEDNESDAY WITH THE CWA STILL IN THE
WARM SECTOR AHEAD OF THE FRONT. MID-LEVEL MOISTURE CONTINUES TO BE
LIMITED...AND ALTHOUGH LIGHT RAIN/SHOWER CHANCES DO INCREASE WITH
THE APPROACH OF THE LOW/COLD FRONT THE BEST COVERAGE AND RAINFALL
AMOUNTS EXPECTED NORTH OF THE AREA ACROSS WI AND THE NORTHERN LAKES.
THE COLD FRONT PUSHES ACROSS THE AREA WEDNESDAY EVENING...SHUTTING
OFF PRECIP AS MID/UPPER LEVELS DRY OUT. THANKS TO WEST-SOUTHWEST
FLOW ALOFT THE FIRST PUSH OF COLDER AIR IS RELATIVELY WEAK...AS THE
FRONT AND LOW LEVEL BAROCLINIC ZONE SLOW UP FROM THE OHIO VALLEY TO
THE EASTERN LAKES INTO THURSDAY. A COUPLE OF DISTURBANCES RIPPLE
NORTHEAST ALONG THIS BAROCLINIC ZONE LATE THURSDAY INTO FRIDAY...
WITH THE POTENTIAL FOR SOME LIGHT SNOW FROM CENTRAL IL INTO NORTHERN
INDIANA AND MAINLY CLIPPING THE FAR SOUTHEAST PART OF THE CWA. A
SECOND PUSH OF COLDER AIR THEN SPREADS IN THURSDAY NIGHT-FRIDAY AS
THE UPPER LOW PASSES TO THE NORTH AND HEADS INTO EASTERN CANADA.
THIS ALLOWS 850 MB AIR OF -10 TO -15 C ACROSS THE AREA AND TEMPS A
GOOD 8-10F COLDER FRIDAY THAN ON THURSDAY. SOME DIFFERENCES REMAIN
WITH MODEL DETAILS AT THIS TIME...BUT CONTINUE TO FAVOR THE SIMILAR
GEM/ECMWF WHICH SUPPORTS HIGHS ONLY NEAR/AROUND 20 FRIDAY AND
SATURDAY AS ARCTIC HIGH PRESSURE BUILDS ACROSS THE MIDWEST. LOOKS
LIKE AT LEAST SOME SLIGHT MODERATION SUNDAY-MONDAY AS UPPER TROUGH
AMPLIFIES ACROSS THE WESTERN CONUS/NOAM...WITH AN AREA OF LOW
PRESSURE LIFTING ACROSS THE AREA SUNDAY WITH THE POTENTIAL FOR SOME
LIGHT SNOW.
RATZER
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* IFR/LIFR CIGS/VIS LOWERING TO LIFR/VLIFR THIS EVENING/TONIGHT.
* SOUTHEASTERLY WINDS AROUND 10 KT THROUGH EARLY EVENING.
* FOG WITH 1/2SM OVERNIGHT INTO WEDNESDAY MORNING.
* CHANCE OF SHOWERS WEDNESDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER THE SOUTH CENTRAL PLAINS WILL LIFT NORTHEAST
OVER MISSOURI WEDNESDAY MORNING...THEN MOVE NORTHEAST ACROSS
EASTERN IOWA AND NORTHWEST IL EARLY WEDNESDAY AFTERNOON. A WARM
FRONT EXTENDING EAST FROM THIS LOW...CURRENTLY ACROSS CENTRAL IL...
IS EXPECTED TO LIFT NORTH ACROSS THE TERMINALS OVERNIGHT INTO
WEDNESDAY MORNING. HOWEVER...CONFIDENCE REGARDING ITS SPEED AND
LOCATION IS LOW AND THIS CREATES A CHALLENGING FORECAST FOR FOG
POTENTIAL THIS EVENING THROUGH WEDNESDAY MORNING. PREVAILING
VISIBILITIES HAVE REMAINED IN THE 1-2SM WITH RFD NOW SLOWING
APPROACHING 1SM. WITH THE WARM FRONT EXPECTED TO REMAIN SOUTH OF
THE TERMINALS THROUGH AT LEAST THIS EVENING...EXPECT THE VIS TO
LOWER BACK UNDER 1SM THIS EVENING WITH SOME DRIZZLE POSSIBLE. THE
VIS MAY CONTINUE TO LOWER TO 1/2SM OR A 1/4SM AT SOME LOCATIONS...
ESPECIALLY AT RFD. IF THE WARM FRONT IS ABLE TO MOVE ACROSS
NORTHERN IL TONIGHT...VISIBILITIES WILL LIKELY IMPROVE INTO THE
1-2SM RANGE OR BETTER. HOWEVER...ITS POSSIBLE THE FRONT WILL SLOW
OR STALL AND IF THIS OCCURS...VISIBILITIES WILL LIKELY TANK
OVERNIGHT AND PERSIST INTO WEDNESDAY MORNING...WHEN THE WARM FRONT
WILL FINALLY MOVE ACROSS THE AREA.
WIND DIRECTIONS WILL REMAIN SOUTHEASTERLY AROUND 10KTS THIS
AFTERNOON...THEN DIMINISH THIS EVENING. SPECIFIC DIRECTIONS
TONIGHT INTO WEDNESDAY MORNING WILL DEPEND ON THE WARM FRONT
MOVEMENT/TIMING...LIKELY REMAINING MORE SOUTHEAST OR EVEN EAST/
SOUTHEAST NORTH OF THE FRONT WITH SOUTHERLY WINDS SOUTH OF THE
FRONT. CMS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH FOR CIG/VIS TRENDS INTO THIS EVENING.
* MEDIUM FOR CIG/VIS TRENDS OVERNIGHT AND WEDNESDAY MORNING.
* MEDIUM FOR WIND SPEEDS/DIRECTIONS THROUGH THE PERIOD.
* LOW FOR SHOWERS WEDNESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.MARINE...
239 AM CST
STILL SIGNIFICANT DIFFERENCES IN THE MODELS WITH RESPECT TO LOW
PRESSURE THAT IS EXPECTED TO IMPACT THE LAKES MIDWEEK. GUIDANCE HAS
TRENDED TOWARDS A SLOWER FRONTAL TIMING AND MORE NORTHERLY LOW TRACK
THOUGH...A TYPICAL TREND WHEN THE UPPER AIR PATTERN IS AMPLIFIED.
WITH THAT IN MIND...HAVE BASED FORECAST TIMING ON A BLEND OF THE GEM
AND THE ECWMF WHICH HAVE BEEN FAIRLY CONSISTENT WITH SLOWER TIMING
AND WHICH THE FASTER NCEP GUIDANCE SEEMS TO BE TRENDING TOWARDS. A
DEEPENING AREA OF LOW PRESSURE IS EXPECTED TO LIFT FROM THE CENTRAL
PLAINS TODAY AND TOMORROW...ACROSS LAKE SUPERIOR OR WEDNESDAY NIGHT.
MODERATE SOUTHEAST TO EAST WINDS ARE EXPECTED AHEAD OF THE
LOW...THOUGH STABLE CONDITIONS WILL HELP KEEP THE HIGHER END GUSTS
FROM REACHING THE LAKE SURFACE. BEHIND THE FRONT...STRONG AND COLD
HIGH PRESSURE WILL OVERSPREAD THE PLAINS WITH A TIGHT GRADIENT ONLY
VERY GRADUALLY SUBSIDING THROUGH THE REST OF THE WEEK. THERE MAY BE
A SHORT PERIOD OF WESTERLY GALES IMMEDIATELY BEHIND THE FRONT
WEDNESDAY NIGHT INTO THURSDAY...WITH 30KTS REST OF THURSDAY INTO
FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ019-ILZ020-ILZ021-ILZ032 UNTIL 1 PM TUESDAY.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY
IS UNTIL 3 PM TUESDAY.
&&
$$
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AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1055 AM CST TUE DEC 3 2013
.DISCUSSION...
1055 AM CST
HAVE EXTENDED THE DENSE FOG ADVISORY A COUPLE HOURS ACROSS NORTH
CENTRAL IL AS WELL AS EXPAND IT EASTWARD INTO THE FAR WESTERN
CHICAGO SUBURBS. ALSO HAVE BUMPED DOWN HIGH TEMPERATURES SEVERAL
DEGREES GIVEN THE LIMITED WARM ADVECTION NOT BEING ABLE TO OFFSET
NULL SOLAR HEATING.
OBSERVED VISIBILITY AND WEBCAMS ACROSS MUCH OF NORTH CENTRAL AND
NORTHWEST IL INDICATE LITTLE IMPROVEMENT HAS OCCURRED WITH T/TD
SPREADS ALMOST ENTIRELY AT 1F OR LESS. WITH TEMPERATURES STILL
AROUND 40 AND QUITE A WAYS FROM THAT 48-50 NEEDED ON THE 12Z DVN
RAOB TO BREAK THROUGH INTO BETTER MIXING...NOT EXPECTING RAPID
IMPROVEMENT. HIGH RES MODELS AND ENSEMBLES SUCH AS THE HRRR AND
NARRE-TL INDICATE SLIGHT VISIBILITY IMPROVEMENT THIS
AFTERNOON...WHILE ALSO BOTH INDICATING SUSCEPTIBILITY TO DROPPING
RIGHT BACK INTO DENSE FOG AFTER DARK WHICH CONCEPTUALLY MAKES
SENSE WITH THE AREA ALONG/NORTH OF THE WARM FRONT. HOW QUICKLY THE
WARM FRONT PROGRESSES NORTHWARD TONIGHT IS HIGHLY UNCERTAIN AND
SOMETHING MODELS MAY PROGRESS TOO QUICKLY. HAVE FOR THE TIME BEING
ADDED AREAS OF FOG MENTION ACROSS THE CWA.
INTERMITTENT LIGHT RAIN/DRIZZLE SHOULD CONTINUE WITH ANOTHER
SMALL SCALE MID-LEVEL IMPULSE HELPING TO BRING A BIT OF ENHANCED
WARM AIR ADVECTION/ISENTROPIC ASCENT AND JUST SOME BROAD AND WEAK
OMEGA.
TEMPERATURES WILL OOZE UPWARD AND MAY REACH THEIR MAXS TOWARD 4-5
PM...ABOUT 1-2 HRS LATER THAN TYPICAL THIS TIME OF YEAR.
TEMPERATURES SHOULD BASICALLY HOLD STEADY INTO THE EVE AND MAY
CLIMB LATER INTO THE NIGHT.
MTF
&&
//PREV DISCUSSION...
330 AM CST
FORECAST FOCUS REMAINS LARGELY ON THE NEAR TERM THIS MORNING...
NAMELY PRECIPITATION AND TEMPERATURE TRENDS TODAY THROUGH WEDNESDAY
AS DEEP LOW PRESSURE SYSTEM DEVELOPS IN RESPONSE TO AMPLIFICATION OF
UPPER TROUGH ACROSS THE WESTERN/CENTRAL CONUS. DAYS 3-7 CONTINUE TO
FEATURE MUCH COLDER THAN AVERAGE TEMPERATURES...WITH THE POTENTIAL
FOR A COUPLE OF LIGHT SNOW EVENTS MAINLY ACROSS THE FAR SOUTHEAST
LATE THURSDAY-FRIDAY...AND FOR MOST OF THE AREA SUNDAY/SUNDAY NIGHT.
00Z RAOB ANALYSIS INDICATES FAIRLY ZONAL FLOW PATTERN ACROSS THE
CENTRAL CONUS...WITH A DEEP SHORT WAVE TROUGH DIGGING SOUTHEAST
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SEVERAL RELATIVELY MINOR
AMPLITUDE SHORT WAVES WERE NOTED DOWNSTREAM ACROSS THE MIDWEST...
EMANATING FROM STRONG JET STREAK DEVELOPS AROUND THE SOUTHERN
PERIPHERY OF THE DIGGING TROUGH. ONE SUCH WAVE WAS NOTED IN WATER
VAPOR IMAGERY OVER THE UPPER MISSISSIPPI VALLEY EARLY THIS
MORNING...WHICH WAS RESPONSIBLE FOR AN AREA OF WARM ADVECTION
PRECIPITATION THAT MOVED ACROSS THE FORECAST AREA OVERNIGHT AND WAS
NOW EAST OF THE REGION. A COUPLE OF MORE SUBTLE MID-LEVEL WAVES WERE
NOTED IN THE SATELLITE IMAGERY...ONE APPROACHING QUICKLY FROM
EASTERN IA...AND THE OTHER UPSTREAM ACROSS WESTERN NEBRASKA. THESE
FEATURES WILL RIPPLE QUICKLY EAST ACROSS THE AREA TODAY...MAINLY
WORKING TO MAINTAIN SOUTHERLY FLOW AND CONTINUED WARM ADVECTION INTO
THE MIDWEST. WHILE SOME SPOTTY LIGHT RAIN IS POSSIBLE WITH ANY OF
THESE SUBTLE FEATURES...UPSTREAM SOUNDINGS FROM OMA/TOP/SGF INDICATE
FAIRLY DRY MID-LEVELS. FORECAST SOUNDINGS MAINTAIN THIS DRY LAYER
ROUGHLY BETWEEN 850-650 MB WHICH SUGGESTS MAINLY SCATTERED LIGHT
RAIN OR SOME DRIZZLE WITH ONLY LIGHT QPF AMOUNTS TODAY-TONIGHT AS
FORCING WITH THESE WAVES ACT ON MOIST LOW LEVELS OR BRIEF POCKETS OF
ENHANCED MID-LEVEL MOISTURE.
WITH ONGOING WARM ADVECTION...SURFACE TEMPERATURES AND DEW POINTS
WILL CONTINUE TO SLOWLY RISE AS A WARM FRONT CURRENTLY LIFTING INTO
CENTRAL ILLINOIS MOVES NORTH. WHILE THE BOUNDARY REMAINS A BIT
DIFFUSE EARLY THIS MORNING...THE FRONT SHOULD SHARPEN AND BEGIN TO
MOVE FASTER LATER TODAY AND TONIGHT AS SURFACE LOW PRESSURE DEEPENS
TO OUR WEST ACROSS THE CENTRAL PLAINS IN RESPONSE TO HEIGHT FALLS
WITH DEEPENING WESTERN TROUGH. MODELS ARE IN FAIRLY GOOD AGREEMENT
THAT THE SURFACE WARM FRONT SHOULD LIFT INTO NORTHERN IL BY LATE
AFTERNOON...WITH THE SOUTHERN AND CENTRAL PARTS OF THE CWA GETTING
INTO THE WARM SECTOR. TEMPS SHOULD REACH THE LOW-MID 50S ALONG AND
SOUTH OF I-80 THIS AFTERNOON...WITH 40S TO THE NORTH. IT WILL REMAIN
VERY MILD TONIGHT AS THE WARM FRONT REACHES THE IL/WI BORDER...WITH
OVERNIGHT LOWS HOLDING IN THE 40S ACROSS THE CWA.
GUIDANCE REMAINS IN TWO SEPARATE CAMPS WITH THE HANDLING OF THE MAIN
SURFACE LOW AND COLD FRONT ON WEDNESDAY...WITH THE DOMESTIC MODELS
REMAINING FASTER AND INITIALLY DEEPER BEYOND 30 HOURS THAN THE UK/EC
AND CANADIAN COUNTERPARTS. THE 00Z RUNS OF THE GFS AND TO A GREATER
EXTENT THE WRF HAVE SLOWED HOWEVER...WHICH LENDS SUPPORT TO OUR
FAVORING THE SLOWER SOLUTION OF THE UKMET/ECMWF AND GEM. THUS
CONTINUE TO FAVOR THE SCENARIO OF THE SURFACE LOW LIFTING ACROSS
EASTERN IOWA INTO WI WEDNESDAY AFTERNOON...AND THE TRAILING COLD
FRONT MOVING ACROSS THE WFO LOT FORECAST AREA FAIRLY LATE IN THE
AFTERNOON AND EVENING HOURS. THIS SUPPORTS TEMPS IN THE 50S...AND
EVEN A COUPLE OF 60S FAR SOUTH...WEDNESDAY WITH THE CWA STILL IN THE
WARM SECTOR AHEAD OF THE FRONT. MID-LEVEL MOISTURE CONTINUES TO BE
LIMITED...AND ALTHOUGH LIGHT RAIN/SHOWER CHANCES DO INCREASE WITH
THE APPROACH OF THE LOW/COLD FRONT THE BEST COVERAGE AND RAINFALL
AMOUNTS EXPECTED NORTH OF THE AREA ACROSS WI AND THE NORTHERN LAKES.
THE COLD FRONT PUSHES ACROSS THE AREA WEDNESDAY EVENING...SHUTTING
OFF PRECIP AS MID/UPPER LEVELS DRY OUT. THANKS TO WEST-SOUTHWEST
FLOW ALOFT THE FIRST PUSH OF COLDER AIR IS RELATIVELY WEAK...AS THE
FRONT AND LOW LEVEL BAROCLINIC ZONE SLOW UP FROM THE OHIO VALLEY TO
THE EASTERN LAKES INTO THURSDAY. A COUPLE OF DISTURBANCES RIPPLE
NORTHEAST ALONG THIS BAROCLINIC ZONE LATE THURSDAY INTO FRIDAY...
WITH THE POTENTIAL FOR SOME LIGHT SNOW FROM CENTRAL IL INTO NORTHERN
INDIANA AND MAINLY CLIPPING THE FAR SOUTHEAST PART OF THE CWA. A
SECOND PUSH OF COLDER AIR THEN SPREADS IN THURSDAY NIGHT-FRIDAY AS
THE UPPER LOW PASSES TO THE NORTH AND HEADS INTO EASTERN CANADA.
THIS ALLOWS 850 MB AIR OF -10 TO -15 C ACROSS THE AREA AND TEMPS A
GOOD 8-10F COLDER FRIDAY THAN ON THURSDAY. SOME DIFFERENCES REMAIN
WITH MODEL DETAILS AT THIS TIME...BUT CONTINUE TO FAVOR THE SIMILAR
GEM/ECMWF WHICH SUPPORTS HIGHS ONLY NEAR/AROUND 20 FRIDAY AND
SATURDAY AS ARCTIC HIGH PRESSURE BUILDS ACROSS THE MIDWEST. LOOKS
LIKE AT LEAST SOME SLIGHT MODERATION SUNDAY-MONDAY AS UPPER TROUGH
AMPLIFIES ACROSS THE WESTERN CONUS/NOAM...WITH AN AREA OF LOW
PRESSURE LIFTING ACROSS THE AREA SUNDAY WITH THE POTENTIAL FOR SOME
LIGHT SNOW.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* IFR/LIFR CIGS THROUGH WEDNESDAY MORNING.
* CHANCE OF SHOWERS THIS MORNING.
* SOUTHEAST WINDS APPROACHING 10KTS...TURNING MORE SOUTHERLY THIS
AFTERNOON.
* POTENTIAL FOR DENSE FOG TONIGHT/WEDNESDAY MORNING. CMS
//DISCUSSION...UPDATED 14Z...
CIGS/VIS CONTINUE TO TANK ACROSS NORTHWEST AND NORTH CENTRAL IL
THIS MORNING WITH RFD...AND SEVERAL OTHER SITES...AT 1/4SM. THIS
TREND WILL CONTINUE EAST INTO THE CHICAGO AREA TERMINALS WITH
PREVAILING VIS DROPPING INTO THE 1-2SM RANGE...POSSIBLY LOWER AT
DPA. CMS
PREVIOUS 12Z DISCUSSION...
TRICKY FORECAST ON TAP TODAY...WITH IFR CONDITIONS EXPECTED MUCH OF
THE TAF PERIOD. AN ILL-DEFINED WARM FRONTAL BOUNDARY IS DRAPED
ACROSS CENTRAL ILLINOIS AND IS EXPECTED TO GRADUALLY LIFT NORTH
ACROSS THE TERMINALS TODAY. AHEAD OF THE FRONT...IFR CIGS...FOG AND
LIGHT DRIZZLE/RAIN ARE ALL A LIKELIHOOD. WINDS WILL BE OUT OF THE
SE/SSE THROUGH MUCH OF THE DAY...AND MAY VEER BRIEFLY LATE THIS
AFTERNOON AS THE FRONTAL BOUNDARY MAKES IT NEAR THE STATE LINE
BEFORE WASHING OUT. GUIDANCE NOT IN THE BEST AGREEMENT ON WIND
DIRECTION...WITH SOME SUGGESTING WE MAY GO SSW...WHILE MOST KEEP
WIND DIRECTION SSE. ALSO...NAM GUIDANCE SUGGESTS THAT CIGS MAY
BRIEFLY SCATTER OUT SOUTH OF THE FRONT...BUT CONFIDENCE IN THIS
HAPPENING IS TOO LOW TO INCLUDE IN THE TAF AS DEEPENING AREA OF LOW
PRESSURE OVER THE PLAINS WILL BASICALLY CAUSE THE WARM FRONT TO
REORGANIZE BACK TO OUR SOUTH LATE THIS EVENING. THIS BETTER DEFINED
FRONT WILL GRADUALLY LIFT NORTH TOWARDS THE AREA TONIGHT WITH CIGS
EXPECTED TO ONCE AGAIN LOWER AND LIGHT DRIZZLE DEVELOP. THERE IS A
GOOD POSSIBILITY OF DENSE FOG DEVELOPING TONIGHT AS THE FRONTAL
TROUGH NEARS...SIMILAR TO WHAT HAPPENED ACROSS MUCH OF THE MID AND
LOWER MISSISSIPPI VALLEY THIS MORNING. MET/LAV GUIDANCE HITTING THIS
THE HARDEST...BUT FOR NOW WILL STICK WITH MAV/S MORE CONSERVATIVE
FORECAST.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH FOR VIS/CIGS THROUGH THIS AFTERNOON...MEDIUM THIS EVENING
THROUGH WEDNESDAY MORNING.
* MEDIUM SHOWERS WILL STAY NORTH OF ORD/MDW THIS MORNING.
* MEDIUM FOR WIND SPEEDS/DIRECTIONS THROUGH THE PERIOD.
* LOW FOR DENSE FOG TONIGHT/WEDNESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR POSSIBLE. SLT CHC OF RAIN.
THURSDAY THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW.
MONDAY...MVFR POSSIBLE.
BMD
&&
.MARINE...
239 AM CST
STILL SIGNIFICANT DIFFERENCES IN THE MODELS WITH RESPECT TO LOW
PRESSURE THAT IS EXPECTED TO IMPACT THE LAKES MIDWEEK. GUIDANCE HAS
TRENDED TOWARDS A SLOWER FRONTAL TIMING AND MORE NORTHERLY LOW TRACK
THOUGH...A TYPICAL TREND WHEN THE UPPER AIR PATTERN IS AMPLIFIED.
WITH THAT IN MIND...HAVE BASED FORECAST TIMING ON A BLEND OF THE GEM
AND THE ECWMF WHICH HAVE BEEN FAIRLY CONSISTENT WITH SLOWER TIMING
AND WHICH THE FASTER NCEP GUIDANCE SEEMS TO BE TRENDING TOWARDS. A
DEEPENING AREA OF LOW PRESSURE IS EXPECTED TO LIFT FROM THE CENTRAL
PLAINS TODAY AND TOMORROW...ACROSS LAKE SUPERIOR OR WEDNESDAY NIGHT.
MODERATE SOUTHEAST TO EAST WINDS ARE EXPECTED AHEAD OF THE
LOW...THOUGH STABLE CONDITIONS WILL HELP KEEP THE HIGHER END GUSTS
FROM REACHING THE LAKE SURFACE. BEHIND THE FRONT...STRONG AND COLD
HIGH PRESSURE WILL OVERSPREAD THE PLAINS WITH A TIGHT GRADIENT ONLY
VERY GRADUALLY SUBSIDING THROUGH THE REST OF THE WEEK. THERE MAY BE
A SHORT PERIOD OF WESTERLY GALES IMMEDIATELY BEHIND THE FRONT
WEDNESDAY NIGHT INTO THURSDAY...WITH 30KTS REST OF THURSDAY INTO
FRIDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ019-ILZ020-ILZ021-ILZ032 UNTIL 1 PM TUESDAY.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 3 PM TUESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
345 PM CST TUE DEC 3 2013
.SYNOPSIS...
ISSUED AT 340 PM CST TUE DEC 3 2013
WARM FRONT REACHING FROM DEVELOPING LOW OVER SE CO REACHED E-NE
ACROSS CENTRAL KS TO S CENTRAL IA TO N CENTRAL IL THIS AFTERNOON. AT
21Z...SURFACE ANALYSIS AND VISIBLE SATELLITE IMAGERY INDICATED THE
BOUNDARY BETWEEN FAIRFIELD AND WASHINGTON SE TO BETWEEN GALESBURG AND
MACOMB. FOG WAS WIDESPREAD NORTH OF THIS BOUNDARY AND HAS REMAINED
DENSE THROUGH THE DAY ALONG THE HIGHWAY 20 CORRIDOR. SOUTH OF THE
BOUNDARY...TEMPERATURES WERE IN THE 50S...WHILE 40S WERE FOUND TO
THE NORTH. THE PRIMARY PUSH OF ARCTIC AIR WAS STILL IN THE
PLAINS...WHERE THE MAIN COLD FRONT REACHED FROM NW MN S-SW TO THE
NEB PANHANDLE. BEHIND THIS BOUNDARY...TEMPERATURES WERE IN THE TEENS
AND 20S.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 340 PM CST TUE DEC 3 2013
THE REBOUND OF WIDESPREAD DENSE FOG IS THE INITIAL CHALLENGE...THEN
TRENDS WITH THE PASSAGE OF THE STRONG COLD FRONT THAT IS NOW LIKELY
TO PUSH THROUGH WED AFTERNOON.
THE WARM FRONT WILL TRY TO PUSH NORTH TONIGHT AS THE CO LEE LOW
MIGRATES NORTHEAST ALONG THE BOUNDARY IN KS. THE BROAD LOW LEVEL
CONVERGENT FLOW AND MOISTURE ADVECTION AS DEWPOINTS IN THE 40S OVER
MO AND IL ARE DRAWN NORTH AND NORTHWESTWARD WILL KEEP THE LOW LEVELS
SATURATED. THE HRRR AND SREF FOG PROG TOOLS ARE IN ALIGNMENT WITH
THE CURRENT AREA OF DENSE FOG AND HAVE THIS EXPANDING BACK SOUTH AND
SOUTHWEST OVERNIGHT. THIS IS ALONG THE AREA OF CURRENT CONVERGENCE
FROM S CENTRAL IA NE TO NW IL AND HAVE EXPANDED OUR DENSE FOG
ADVISORY TO COVER THESE AREAS OVERNIGHT. HAVE THIS GOING UNTIL NOON
WEDNESDAY...WHEN THE ENHANCED MIXING AHEAD OF THE FRONT SHOULD BRING
SOME IMPROVEMENT. ACROSS FAR SOUTHEAST IA...FAR NE MO AND WEST
CENTRAL IL ALONG THE I-80 CORRIDOR...FOG WILL LIKELY RETURN...BUT
THERE IS LOW CONFIDENCE AS TO WHETHER IT WILL BECOME DENSE. HAVE
THUS HELD OFF ON AN ADVISORY...BUT WILL NEED TO MONITOR CLOSELY.
OTHERWISE...THE DEVELOPING LIFT AND INCREASING DIFLUENCE IN FLOW
ALOFT WILL SUPPORT ANOTHER ROUND OF LIGHT RAIN...ESPECIALLY TOWARD
MORNING ACROSS THE NORTH AND HAVE MAINTAINED CHANCE POPS.
ELSEWHERE...WILL KEEP A MENTION OF DRIZZLE WITH THE FOG.
WEDNESDAY...LATEST MODELS CONTINUE TO TREND TOWARD THE
EARLIER...SLOWER ECMWF RUNS WITH THE TIMING OF THE FROPA. THE
GFS...NAM...ECMWF...AND GEM OFFER SIMILAR SOLUTIONS WITH THE WAVE OF
LOW PRESSURE MOVING OUT OF THE PLAINS...LIFTING THROUGH THE FORECAST
AREA WEDNESDAY AFTERNOON. THIS USHERS THE PRIMARY COLD FRONT THROUGH
THE AREA BY EARLY EVENING. HAVE TRENDED THE FORECAST TOWARD THE
SLIGHTLY SLOWER ECMWF AND CANADIAN SOLUTIONS...KEEPING THE
PRECIPITATION IN THE FORM OF RAIN WITH A POSSIBLY RAIN/SNOW MIX IN
THE FAR NW LATE. WITH THE PRIMARY WARM SECTOR SWEEPING THROUGH THE
MUCH OF THE WARM SECTOR...WE SHOULD TAP INTO THE AIRMASS OVER
EASTERN MO AND SOUTHERN IL RESULTING IN MORNING OR EARLY AFTERNOON
HIGHS FROM THE LOWER 40S NW TO NEAR 60 IN THE FAR SE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 340 PM CST TUE DEC 3 2013
WEDNESDAY NIGHT THROUGH FRIDAY...TAKING INTO ACCOUNT A TYPE OF
ENSEMBLE FRONTAL MOVEMENT OF THE 12Z MODEL RUNS AND EVEN SLOWING
THAT DOWN SOME AS DEEPENING CYCLONE WRAPS UP SOMEWHERE ACRS
SOUTHWEST INTO CENTRAL WI WED EVENING...IT SHOULD BE PUSHING EAST OF
THE DVN CWA BY 01Z-02Z THU. CONVERGENT FORCING OFF THIS PROCESS MAY
WRING OUT SOME LIGHT RAIN OR DRIZZLE ALONG AND EAST OF THE MS RVR THE
FIRST 1-2 HRS OF THE FCST PERIOD. BUT THE MAIN OVERNIGHT WX STORY
WILL BE THE INCREASING WESTERLY POST-FRONTAL SFC WINDS AND DEVELOPING
LLVL COLD CONVEYOR IN-WRAPPING FROM THE NORTHWEST. BRISK WEST WINDS
OF 15 TO 25+ MPH SHOULD COLD AIR ADVECT TEMPS INTO THE UPPER TEENS
IN THE NORTHWEST...TO THE MID 20S IN THE EAST BY THU MORNING. THE
12Z RUNS THEN SUGGEST THAT AS 1035-1040 MB HIGH DUMPS DOWN THE
NORTHWESTERN PLAINS AND TIGHT CYCLONIC GRADIENT LINGERS SOME OFF
NORTHERN GRT LKS DEEP LOW PRESSURE CENTER...WINDY CONDITIONS TO
CONTINUE THROUGH AT LEAST MIDDAY THU WITH AMBIENT TEMPS ONLY
RECOVERING 3-5 DEGREES FROM MORNING VALUES AT 12Z THU. SINGLE DIGIT
ABOVE ZERO WIND CHILLS IN THE NORTHWESTERN HALF OF THE CWA THU AM.
THE ARCTIC FRONT SURGES SOUTH AND PRODUCES TIGHTENING LLVL
BAROCLINICITY AS IT SLOWS UNDER SOUTHWESTERLIES ACRS THE DEEP
SOUTHERN PLAINS TO SOUTHEASTERN OH RVR VALLEY. ALONG AND NORTH OF
THIS THERMAL RIBBON TO BE AN AXIS FOR WINTER STORM/ICE CONDITIONS
INTO FRI AND THERE IS STILL SOME VARIANCE BETWEEN THE LATEST RUN
SOLUTIONS OF FRONTAL PLACEMENT AND STRENGTH OF A WAVE RIPPLING UP
ALONG THIS HIGHWAY. THE MAJORITY OF THE 12Z MODEL RUNS STILL KEEP
ANY OVERRUNNING SNOW OFF TO THE SOUTHEAST OF THE CWA THU THROUGH FRI
WITH JUST A MID AND HIGH LEVEL CLOUD DECK MOVING UP ACRS PORTIONS OF
THE CWA LATE IN THE DAY AND OVERNIGHT. BUT THE 12Z RUN NAM AND GEM
ARE MORE BULLISH AND FURTHER NORTH WITH THE OVERRUNNING PRECIP
SHIELD AND CLIP AT LEAST THE SOUTHEASTERN THIRD OF THE DVN CWA WITH
LIGHT SNOW THU NIGHT INTO FRI MORNING. FOR NOW WILL MAINTAIN SLIGHT
CHC POPS ACRS THE FAR SOUTH AND SOUTHEASTERN CORNER OF THE FCST
AREA. MOSTLY CLOUDY...BLUSTERY AND COLD CONDITIONS CONTINUE ON FRI
WITH HIGHS ONLY IN THE UPPER TEENS TO LOWER 20S. THE INCOMING SFC
RIDGE WILL LOOK TO UNFOLD ACRS THE UPPER MS RVR VALLEY FRI NIGHT FOR
CLEARING...SFC WIND DECREASING AND COLD CONDITIONS. MANY LOWS IN THE
SINGLE DIGITS WITH A ZERO EVEN POSSIBLE IN THE NORTHWEST.
SATURDAY AND SUNDAY...THE SFC RIDGE MAINTAINS LOCALLY LONG ENOUGH FOR
A FAIR WX BUT COLD DAY SAT WITH HIGHS IN THE TEENS TO AROUND 20 AS
L/W TROF LOOMS ACRS THE SOUTHWESTERN CONUS/GRT BSN. THE MEDIUM RANGE
SOLUTIONS THEN SUGGEST NORTHERN STREAM UPPER JET ENERGY/TROFFINESS
ACRS WESTERN INTO CENTRAL CANADA TO TRY AND PHASE WITH THIS SW
CONUS LONG WAVE. THE LATEST MODEL RUNS PROBABLY STILL TRYING TO GET A
HANDLE ON THIS PROCESS AND IT WILL BE SUBJECT TO CHANGE...BUT THE
CURRENT SIGNAL SUGGESTS AT LEAST A DECENT SIZED PIECE OF WAVE ENERGY
EJECTING OUT OF THE SOUTHERN PLAINS AND THEN SOMEWHERE UP THE OH
RVR VALLEY OR EVEN FURTHER TO THE NORTHWEST SUNDAY INTO MONDAY. WITH
COLD AIR IN PLACE...THIS COULD SPELL AN EXTENDED PERIOD OF SNOW
MOVING UP ACRS PORTIONS OR ALL OF THE DVN CWA STARING OUT LATE SAT
NIGHT IN THE SOUTHWEST...AND THEN CONTINUING THROUGH LATE SUNDAY
NIGHT OR EARLY MON MORNING. THE CURRENT MODELS INCLUDING THE 12Z RUN
GFS AND ECMWF SUGGEST THE BETTER MOISTURE TRANSPORT TO FUEL HEAVIER
PRECIP TO GET PINCHED OFF/REMAIN TO THE SOUTH AND SOUTHEAST OF THE
LOCAL FCST AREA...WITH JUST SECONDARY SNOWS OF 1-3 INCHES ACRS THE
DVN CWA BY 12Z MON...SNOW MOVING OUT JUST AFTER THAT TIME-FRAME. BUT
THE DURATION/24 HRS OF ROUNDS OF AT LEAST LIGHT TO OCCASIONAL
MODERATE SNOW AND HIGHER LSR/S SUGGEST AMOUNTS COULD ADD UP TO BE
MORE. IF THE MOISTURE CONVEYOR IS LESS IMPEDED AND THE SYSTEM PULLS
UP FURTHER TO THE NORTHWEST...THERE MAY BE THE POTENTIAL FOR A MORE
SIGNIFICANT WINTER STORM IN PORTIONS OF OR CLOSE TO THE LOCAL AREA.
A WINDOW TO WATCH FOR SURE...AND WILL HAVE TO SEE HOW ADDITIONAL
MODEL RUNS BEHAVE AND HANDLE THE PHASING PROCESS. WILL RAISE THE CHC
POPS FOR NOW FOR SUNDAY NIGHT.
NEXT MONDAY AND TUESDAY...THE LONGER RANGE SIGNALS SUGGEST THAT
AFTER WHAT KIND OF SYSTEM CAN MAKE IT THROUGH OR CLOSE TO THE AREA
SUNDAY INTO EARLY MONDAY...A VERY COLD AIRMASS THEN LOOMS ACRS
CANADA. THE FRESHLY PHASED L/W TROF WILL THEN BECOME COLD CORE AND
ACT AS AN ARCTIC CONDUIT ALLOWING A COLD DUMP DOWN THE NORTHERN
PLAINS AND UPPER MIDWEST LATER MONDAY INTO TUE. THE 12Z GFS HAS A
FRIGID H85 MB COLD POOL OF -20 TO -26C BARRELING IT/S WAY DOWN
ACRS MOST OF THE CWA BY 12Z TUE...THE 12Z ECMWF IS ADVERTISING -19 TO
-21C. EVEN WITH MIXING WINDS WHICH WILL BE BRISK IN THIS TYPE OF
CAA UNDER CYCLONIC FLOW...TEMPS BY TUE MORNING MAY GO SUB-ZERO. MAY
BE WIND CHILL ADVISORY CRITERIA ATTAINED IN PORTIONS OF THE AREA LATE
MON NIGHT AND THROUGH MIDDAY TUE. WELL AGAIN...MANY SYSTEMS AND
PHASING PROCESSES TO GO THROUGH TO GET TO THIS EXTENDED PERIOD BUT
WILL START TO TREND TEMPS DOWN. ..12..
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
UPDATED AT 340 PM CST TUE DEC 3 2013
WIDESPREAD FOG AND LOW CLOUDS RESULTING IN IFR AND LIFR
CONDITIONS ALONG AND NORTH OF A WARM FRONT EXTENDING ACROSS
SOUTHERN IA AND CENTRAL IL WILL REMAIN IN PLACE UNTIL A COLD FRONT
PUSHES THROUGH WEDNESDAY AFTERNOON. CONDITIONS WILL BE WORST AT
DBQ...WHERE ONLY MINOR IMPROVEMENT IS EXPECTED THIS AFTERNOON. VISIBILITIES
BELOW 1/4 MILE AND CIGS ONLY A COUPLE HUNDRED FEET WILL RESULT IN
VLIFR...WITH ONLY TEMPORARY IMPROVEMENTS TO LIFR EXPECTED THIS
AFTERNOON. ELSEWHERE...BRL MAY SEE SOME PERIODS OF MVFR INTO EARLY EVENING...
WHILE DBQ AND MLI REMAIN IFR OR LOWER. EVEN THESE SITES SHOULD
AGAIN SEE LOWERING CONDITIONS TONIGHT WITH WIDESPREAD LIFR AND
VLIFR DUE TO THE DENSE FOG...LOW CLOUDS AND PATCHY LIGHT RAIN OR
DRIZZLE THROUGH WEDNESDAY MORNING.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR BENTON-BUCHANAN-
CLINTON-DELAWARE-DUBUQUE-JACKSON-JONES-LINN.
DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR CEDAR-HENRY IA-
IOWA-JEFFERSON-JOHNSON-KEOKUK-LOUISA-MUSCATINE-SCOTT-VAN
BUREN-WASHINGTON.
IL...DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR CARROLL-JO
DAVIESS-STEPHENSON-WHITESIDE.
DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR ROCK ISLAND.
MO...NONE.
&&
$$
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...12
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
238 PM MST TUE DEC 3 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 157 PM MST TUE DEC 3 2013
AS OF 3 PM CST...2 PM MST...SKIES ACROSS THE TRI-STATE AREA RANGED
FROM PARTLY CLOUDY TO OVERCAST AS HIGH CIRRUS CONTINUES TO PASS
OVER. TEMPERATURES REACHED THE LOW TO MID 60S ACROSS THE AREA WITH
THE EXCEPTION OF SOUTHWEST NEBRASKA. A BACK DOOR COLD FRONT HAS
MOVED IN FROM THE NORTHEAST...KEEPING THINGS ACROSS THE NORTHEASTERN
THIRD OF THE FORECAST AREA COOLER. WINDS HAVE BEEN FROM THE SOUTH
AHEAD OF THE COLD FRONT AND NORTHEAST BEHIND THE BACKDOOR FRONT. THE
MAIN COLD FRONT WAS FINALLY BEGINNING TO MAKE ITS SURGE INTO
NORTHEAST COLORADO. THE FRONT WAS BLOCKED BY A STRONG LEE TROUGH
CENTERED BETWEEN DENVER AND LIMON. THIS LEE TROUGH IS NOW STARTING
TO MOVE SOUTHEAST FROM LATEST RAP MSL ANALYSIS...ALLOWING THE MAIN
COLD FRONT TO SURGE SOUTH.
FOR THIS AFTERNOON AND TONIGHT...THE STRONG ARCTIC FRONT WILL MAKE
ITS PRESENCE FELT AS IT MOVES SOUTH. TEMPERATURES DROP RAPIDLY BY
THE FRONT AS SEEN BY THE 15 TO 20 DEGREE DROPS IN ONE HOUR AT YUMA
AND AKRON COLORADO. IMMEDIATELY BEHIND THE FRONT...GUSTY NORTH WINDS
ARE EXPECTED. WINDS NEAR WIND ADVISORY CRITERIA HAVE NOT BEEN
OBSERVED AND MODELS HAVE BACKED OFF ON WIND SPEEDS FROM YESTERDAYS
RUNS. THERE COULD BE SOME GUSTS THAT APPROACH WIND ADVISORY CRITERIA
BUT THIS SHOULD NOT BE WIDESPREAD NOR PERSISTENT. LOW TEMPERATURES
TONIGHT SHOULD BE ABLE TO DROP INTO THE LOW 10S TO LOW 20S EVEN WITH
DENSE CLOUD COVER. FOR PRECIPITATION CHANCES...MOST OF THE
PRECIPITATION WILL LIKELY HOLD OFF UNTIL AFTER 00Z WITH CHANCES
GRADUALLY INCREASING THROUGHOUT THE NIGHT. MODELS INDICATE THAT THE
ATMOSPHERE GRADUALLY SATURATES THROUGH THE NIGHT...ALLOWING SNOW TO
BEGIN FALLING THIS EVENING OR EARLY TOMORROW MORNING. SOUTHEAST
PORTIONS OF THE FORECAST AREA SHOULD MISS OUT ON THE PRECIPITATION
FOR THE MOST PART BUT COULD SEEM SOME FLURRIES. ACCUMULATIONS WILL
BE LIGHT AS ALL MODELS SHOW LIGHT QPF WITH HEAVIER AMOUNTS WEST
WHERE TERRAIN EFFECTS AND LIFT ARE STRONGER.
FOR TOMORROW...COLD WEATHER WILL CONTINUE WITH HIGH TEMPERATURES LESS
THAN 10 DEGREES WARMER THAN LOW TEMPERATURES TONIGHT. HIGHS ARE ONLY
ADVERTISED TO BE IN THE LOW 10S OVER NORTHEAST COLORADO TO THE MID
20S OUT NEAR HILL CITY. THIS COULD BE GENEROUS CONSIDERING THAT
DENSE CLOUD COVER AND NORTH WINDS SHOULD PERSIST. CHANCES FOR LIGHT
SNOW CONTINUE IN THE MORNING HOURS BEFORE CHANCES DECREASE ACROSS
NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. CHANCES SHOULD CONTINUE
OVER EAST COLORADO WITH A SLIGHT UPSLOPE COMPONENT AND A BETTER
ATMOSPHERIC MOISTURE PROFILE. AGAIN...ONLY LIGHT ACCUMULATIONS ARE
EXPECTED WITH LITTLE IMPACT TO TRAVEL. ANOTHER THING TO NOTE ABOUT
TOMORROW IS THAT WITH THE NORTH WINDS AND COLD TEMPERATURES...WIND
CHILLS SHOULD REMAIN IN THE SINGLE DIGITS ABOVE ZERO THROUGHOUT THE
DAY WITH BELOW ZERO WIND CHILLS POSSIBLE IN EAST COLORADO. NEEDLESS
TO SAY...TOMORROW WILL BE MUCH COLDER WITH HIGH TEMPERATURES ON THE
ORDER OF 20 TO 45 DEGREES COOLER DEPENDING ON THE LOCATION.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 157 PM MST TUE DEC 3 2013
COLD AIR WILL BE THOROUGHLY ENTRENCHED ACROSS THE CENTRAL HIGH
PLAINS REGION AND IS EXPECTED TO REMAIN IN PLACE THROUGH THE
FORECAST PERIOD. FLURRIES TO LIGHT SNOW WILL CONTINUE ACROSS
PORTIONS OF THE FORECAST AREA THROUGH THURSDAY NIGHT AS THE MAIN
UPPER TROUGH AND A COUPLE OF PRECEDING SHORT WAVE TROUGHS LIFT
OUT OF THE SOUTHWEST UNITED STATES AND ACROSS THE HIGH PLAINS REGION.
FRIDAY AND FRIDAY NIGHT WILL BE DRY AND COLD WITH HIGH PRESSURE IN
PLACE AT THE SURFACE IN THE WAKE OF THE UPPER TROUGH AS IT MOVES
QUICKLY TO THE EAST. LATE SATURDAY THROUGH SUNDAY BRINGS ANOTHER
CHANCE OF LIGHT SNOW AS THE NEXT UPPER LOW CENTER MOVES OUT OF THE
SOUTHWEST UNITED STATES AND INTO THE CENTRAL UNITED STATES.
MONDAY THROUGH TUESDAY WILL BE DRY AGAIN IN THE WAKE OF THE SECOND
UPPER SYSTEM WHILE COLD HIGH PRESSURE REMAINS IN PLACE...KEEPING
TEMPERATURES ABOUT 20 DEGREES COLDER THAN AVERAGE THROUGH THE
LONG TERM PORTION OF THE FORECAST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1045 AM MST TUE DEC 3 2013
COMPLICATED WEATHER SCENARIO WILL UNFOLD DURING THE TAF PERIOD. A
STRONG COLD FRONT WILL MOVE THROUGH BOTH TAF SITES...BRINGING
GUSTY NORTH WINDS AND REDUCED CIGS/VIS. AN EASTERN SURGE OF THE
FRONT IS ALREADY THROUGH KMCK WITH THE STRONGER SURGE NOW
ENTERING NORTHEAST COLORADO. AHEAD OF THE FRONT AT KGLD...SOUTH
WINDS HAVE PICKED UP BUT SHOULD RELAX IMMEDIATELY AHEAD OF THE
FRONT. BEHIND THE INITIAL SURGE...CIGS HAVE DROPPED TO LIFR WITH
SOME IFR VIS ACROSS SOUTHWEST NEBRASKA AND THINKING THIS WILL
MAKE IT TO KMCK OVER THE NEXT 2-3 HOURS. LOW CIGS/VIS WILL TAKE
LONGER TO MAKE IT TO KGLD...LIKELY HOLDING OFF UNTIL MAIN SURGE OF
THE FRONT PASSES THROUGH AROUND 00Z OR AFTER. LOW CIGS/VIS AND
GUSTY NORTH WINDS ARE EXPECTED TO CONTINUE BEHIND THE FRONT MOST
OF THE NIGHT AT BOTH SITES. TOMORROW...HAVE INCLUDED MENTIONS OF
SNOW AS AN UPPER LEVEL DISTURBANCE MOVES THROUGH. SNOW SHOULD NOT
BE HEAVY BY ANY STRETCH...LIKELY RANGING FROM A FEW FLURRIES TO
LIGHT SNOW SHOWERS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...RRH
LONG TERM...LOCKHART
AVIATION...RRH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
225 PM CST Tue Dec 3 2013
...Updated Short term discussion...
.SYNOPSIS...
ISSUED AT 1106 AM CST TUE DEC 3 2013
At 12z Tuesday a -35c 500mb low was located over Idaho/western
Montana. A +100kt 300mb jet streak was located in the based of
this upper low and extended from northern Nevada into southern
Wyoming. 700 mb level difluent flow appears to be located across
eastern Wyoming. This was located near the left exit region of
the 300mb jet. Across the Central Plains earlier this morning the
850mb temperatures ranged from +10C at North Platte to +15c at
Amarillo. Dodge City this morning had a 850mb temperature of +13c.
A surface cold front was located across Nebraska at 12z Tuesday.
North of this surface cold front low clouds, gusty north winds and
light snow/fog were observed from the surface observations across
eastern Wyoming and northwest Nebraska. Surface temperatures under
the status were mainly in the 20s. 850mb temperatures north of
this front varied from -9c at South Dakota to -13c at Glasgow MT.
&&
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 222 PM CST TUE DEC 3 2013
12z NAM and GFS along with the latest HRRR and RAP were all in
decent agreement with a cold front surging south across western
Kansas during the overnight hours. Based on 18z verification
between the models and the surface observations the 2m
temperatures across Nebraska from NAM and HRRR were within 3
degrees of the actual temperature, and both of these models were
close with the surface front location. 12z NAM model soundings
across Nebraska also appeared to be picking up on the status
behind this front as well. As a result will stay close to the NAM
and HRRR on timing of the wind shift overnight along with the
magnitude of the cold air advection that will be developing behind
this front overnight as low clouds thicken across western Kansas.
Given the current temperatures behind this front in northern
Nebraska, status and cold air advection that is forecast to spread
into western Kansas later tonight have decided to stay close the
previous forecast which was also similar to the latest MET
guidance. Gusty north winds at 20 to 30 mph are also expected to
develop for several hours behind this front later tonight based
given the tight surface pressure gradient and 925-850mb winds of
25 to 35 knots. These gusty winds by daybreak will easily result
in wind chill values in the single digits by early Wednesday
morning. Isentropic lift/warm air advection along with a deepening
moist layer across portions of north central Kansas approaches a
depth favorable for some very light precipitation, however at
this time have decided not to introduce any type of very light
precipitation east of 183.
On Wednesday the status will slowly erode during the afternoon
and cold air advection continues in the 900mb to 850mb layer. Based
on the 18z Wednesday and 00z Thursday 850mb temperatures from the
NAM and GFS will undercut the MET/MAV guidance for highs.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 132 PM CST TUE DEC 3 2013
Wednesday night/Thursday:
The 03.012Z ECMWF, NAM, and GEM were indicating the potential for some
snow Wednesday night but mainly into Thursday as an 145 kt 250 hPa
jet streak moves across the region. This will create an ageostrophic
response (i.e. acceleration) and cause some synoptic lift across the
forecast area of responsibility. On top of that, the models indicate
low level 285 Kelvin isentropic lift on top of the cold airmass. The
GFS is the oddball out and was ignored as it did not match ensemble
mean nor the aforementioned consensus in the deterministic runs. Will
have to watch for a sneaky snow advisory snow amount being met. One
fly in the ointment is that the low levels are very dry (as expected
with an Arctic intrusion), so this could reduce probabilities for more
significant precipitation measurement. Of course, not ready to buy into
the thermodynamic profiles (particularly the NAM) this far out, but
did trend with higher pops, qpf, and lower temperatures. If a snow pack
does come into fruition, the minimums into Friday morning will have
to be watched as they could bottom into negative territory. Otherwise,
midweek will be cold and have gone with bias corrected mos guidance.
Friday and beyond:
Friday through Saturday will feature a precipitation free forecast as
the region will be between synoptic systems. The next chance of precipitation
in the form of snow will be on Sunday as another trof digs across the
central Rockies and eventually ejects out across the prairies. It is
too early to hammer out details this far out and have stuck with the
weighted blend solution. Temperatures will continue to remain below
normal.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1106 AM CST TUE DEC 3 2013
NAM, and HRRR were both in generally good agreement with the
timing of a cold front as it crosses western Kansas early this
evening. As this front passes, southerly winds at less than 10kts
will shift to the north and increase into the 20 to near 25 kt
range for several hours. Based on the latest model runs of the
HRRR and NAM the wind shift is expected to occur around 00z at
HYS. The wind shift is expected between 02z and 05z at DDC and
GCK. In addition to the gusty north winds following the frontal
passage MVFR status is expected to spread south across western
Kansas overnight. Based on surface observations at 16z north of
this front in Nebraska and bufr soundings the cloud bases are
expected to range from 1000 to 1500 feet.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 21 28 10 13 / 0 0 10 50
GCK 21 26 11 12 / 0 0 30 50
EHA 21 29 7 13 / 0 10 30 50
LBL 23 29 13 13 / 0 0 10 50
HYS 21 28 9 17 / 0 0 20 10
P28 29 35 14 19 / 0 0 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Sugden
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
132 PM CST Tue Dec 3 2013
...Update to long term discussion...
.SYNOPSIS...
ISSUED AT 1106 AM CST TUE DEC 3 2013
At 12z Tuesday a -35c 500mb low was located over Idaho/western
Montana. A +100kt 300mb jet streak was located in the based of
this upper low and extended from northern Nevada into southern
Wyoming. 700 mb level difluent flow appears to be located across
eastern Wyoming. This was located near the left exit region of
the 300mb jet. Across the Central Plains earlier this morning the
850mb temperatures ranged from +10C at North Platte to +15c at
Amarillo. Dodge City this morning had a 850mb temperature of +13c.
A surface cold front was located across Nebraska at 12z Tuesday.
North of this surface cold front low clouds, gusty north winds and
light snow/fog were observed from the surface observations across
eastern Wyoming and northwest Nebraska. Surface temperatures under
the status were mainly in the 20s. 850mb temperatures north of
this front varied from -9c at South Dakota to -13c at Glasgow MT.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 349 AM CST TUE DEC 3 2013
Low level moisture was slowly advecting northward into south central
and southeast Kansas early this morning. This was manifesting itself
as areas of locally dense fog across north central Oklahoma into
southeast Kansas. The High Resolution Rapid Refresh model is
suggesting that fog could be developing into the Medicine Lodge and
Pratt areas by around sunrise and continue into this morning before
burning off. Will add some areas of locally dense fog to the gridded
forecast for a few hours this morning
The upper low and trough over the northern Rockies will continue to
dig south and southeast today. All of the 00z models have slowed the
passage of the front across western Kansas from previous runs. Ahead
of the front, westerly winds will develop today across far southwest
Kansas. This will likely help boost temperatures to near or around
70 in locations from Johnson and Elkhart to around Liberal. Have
raised high temperatures several degrees in that area as well as a
few degrees more around Garden City and Dodge City. With less of a
downslope component expected over central and south central Kansas,
highs should top out in the low to mid 60s.
The cold front should be moving to a position along I-70 by sunset
and then continuing south through the remainder of south central and
southwest Kansas by around or shortly after midnight. Gusty north
winds will develop tonight and there could be a period of time
behind the front that winds are approaching or meeting advisory
criteria. For now will let the next shift assess any need for wind
headlines tonight. Colder air and stratus will push south across
western Kansas overnight. Temperatures should range from around 20
over west central and far southwest Kansas to the mid 20s over south
central Kansas.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 132 PM CST TUE DEC 3 2013
Wednesday night/Thursday:
The 03.012Z ECMWF, NAM, and GEM were indicating the potential for some
snow Wednesday night but mainly into Thursday as an 145 kt 250 hPa
jet streak moves across the region. This will create an ageostrophic
response (i.e. acceleration) and cause some synoptic lift across the
forecast area of responsibility. On top of that, the models indicate
low level 285 Kelvin isentropic lift on top of the cold airmass. The
GFS is the oddball out and was ignored as it did not match ensemble
mean nor the aforementioned consensus in the deterministic runs. Will
have to watch for a sneaky snow advisory snow amount being met. One
fly in the ointment is that the low levels are very dry (as expected
with an Arctic intrusion), so this could reduce probabilities for more
significant precipitation measurement. Of course, not ready to buy into
the thermodynamic profiles (particularly the NAM) this far out, but
did trend with higher pops, qpf, and lower temperatures. If a snow pack
does come into fruition, the minimums into Friday morning will have
to be watched as they could bottom into negative territory. Otherwise,
midweek will be cold and have gone with bias corrected mos guidance.
Friday and beyond:
Friday through Saturday will feature a precipitation free forecast as
the region will be between synoptic systems. The next chance of precipitation
in the form of snow will be on Sunday as another trof digs across the
central Rockies and eventually ejects out across the prairies. It is
too early to hammer out details this far out and have stuck with the
weighted blend solution. Temperatures will continue to remain below
normal.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1106 AM CST TUE DEC 3 2013
NAM, and HRRR were both in generally good agreement with the
timing of a cold front as it crosses western Kansas early this
evening. As this front passes, southerly winds at less than 10kts
will shift to the north and increase into the 20 to near 25 kt
range for several hours. Based on the latest model runs of the
HRRR and NAM the wind shift is expected to occur around 00z at
HYS. The wind shift is expected between 02z and 05z at DDC and
GCK. In addition to the gusty north winds following the frontal
passage MVFR status is expected to spread south across western
Kansas overnight. Based on surface observations at 16z north of
this front in Nebraska and bufr soundings the cloud bases are
expected to range from 1000 to 1500 feet.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 21 29 10 13 / 0 0 10 50
GCK 21 27 11 12 / 0 0 30 50
EHA 21 27 7 13 / 0 10 30 50
LBL 23 30 13 13 / 0 0 10 50
HYS 21 29 9 17 / 0 0 20 10
P28 29 36 14 19 / 0 0 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Gerard
LONG TERM...Sugden
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1110 AM CST Tue Dec 3 2013
...Updated Synopsis and Aviation discussion...
.SYNOPSIS...
ISSUED AT 1106 AM CST TUE DEC 3 2013
At 12z Tuesday a -35c 500mb low was located over Idaho/western
Montana. A +100kt 300mb jet streak was located in the based of
this upper low and extended from northern Nevada into southern
Wyoming. 700 mb level difluent flow appears to be located across
eastern Wyoming. This was located near the left exit region of
the 300mb jet. Across the Central Plains earlier this morning the
850mb temperatures ranged from +10C at North Platte to +15c at
Amarillo. Dodge City this morning had a 850mb temperature of +13c.
A surface cold front was located across Nebraska at 12z Tuesday.
North of this surface cold front low clouds, gusty north winds and
light snow/fog were observed from the surface observations across
eastern Wyoming and northwest Nebraska. Surface temperatures under
the status were mainly in the 20s. 850mb temperatures north of
this front varied from -9c at South Dakota to -13c at Glasgow MT.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 349 AM CST TUE DEC 3 2013
Low level moisture was slowly advecting northward into south central
and southeast Kansas early this morning. This was manifesting itself
as areas of locally dense fog across north central Oklahoma into
southeast Kansas. The High Resolution Rapid Refresh model is
suggesting that fog could be developing into the Medicine Lodge and
Pratt areas by around sunrise and continue into this morning before
burning off. Will add some areas of locally dense fog to the gridded
forecast for a few hours this morning
The upper low and trough over the northern Rockies will continue to
dig south and southeast today. All of the 00z models have slowed the
passage of the front across western Kansas from previous runs. Ahead
of the front, westerly winds will develop today across far southwest
Kansas. This will likely help boost temperatures to near or around
70 in locations from Johnson and Elkhart to around Liberal. Have
raised high temperatures several degrees in that area as well as a
few degrees more around Garden City and Dodge City. With less of a
downslope component expected over central and south central Kansas,
highs should top out in the low to mid 60s.
The cold front should be moving to a position along I-70 by sunset
and then continuing south through the remainder of south central and
southwest Kansas by around or shortly after midnight. Gusty north
winds will develop tonight and there could be a period of time
behind the front that winds are approaching or meeting advisory
criteria. For now will let the next shift assess any need for wind
headlines tonight. Colder air and stratus will push south across
western Kansas overnight. Temperatures should range from around 20
over west central and far southwest Kansas to the mid 20s over south
central Kansas.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 410 AM CST TUE DEC 3 2013
Medium range models indicate a strong upper level trough moving east
across the Intermountain West Wednesday and Thursday while a series
of H5 vort maxes eject out of the trough axis northeast across the
Western High Plains. This will set up the chance for periods of
light precip across portions of western Kansas late Wednesday night
into Thursday. As the elongated upper level trough approaches, an
upper level jet exiting the trough axis will intensify as it climbs
northeast across the Western High Plains reaching speeds in excess
of 130kt by early Thursday morning. Additionally, increased H7
frontogenesis banding is noted migrating across western Kansas
during this same general time frame. Meanwhile, GFS/ECMWF model
soundings show mid/upper level moisture advection into western
Kansas with profiles saturating by early to mid morning Thursday.
Due to this, periods of light snow will be possible across west
central and southwest Kansas late Wednesday night with those
chances spreading eastward into central Kansas Thursday. However,
significant snow accumulations are not expected with model soundings
indicating pw values well under half an inch. Drier conditions are
expected Friday through Saturday afternoon as the upper level wave
opens up and kicks off to the east while another upper level trough
begins to drop south across the Pacific Northwest early in the
weekend.
Temperatures will be below normal Wednesday as cold air surges
southward into western Kansas in wake of a strong cold front pushing
across the region Tuesday afternoon/evening. The NAM/GFS show the
H85 0C isotherm dipping south into the Texas panhandle by mid day
Wednesday while extending back to the northeast into south central
Kansas. As a result, highs are expected to be reached earlier in the
day ranging from the 20s(F) across west central Kansas to the 30s(F)
in south central Kansas. Temperatures will be frigid Thursday and
Friday as the arctic air mass settles into western Kansas with H85
temperatures reaching as low as 15C below. Look for highs only up
into the teens(F) and 20s(F) Thursday and Friday with a gradual
warming trend going into the weekend as the cold air mass begins to
slowly erode.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1106 AM CST TUE DEC 3 2013
NAM, and HRRR were both in generally good agreement with the
timing of a cold front as it crosses western Kansas early this
evening. As this front passes, southerly winds at less than 10kts
will shift to the north and increase into the 20 to near 25 kt
range for several hours. Based on the latest model runs of the
HRRR and NAM the wind shift is expected to occur around 00z at
HYS. The wind shift is expected between 02z and 05z at DDC and
GCK. In addition to the gusty north winds following the frontal
passage MVFR status is expected to spread south across western
Kansas overnight. Based on surface observations at 16z north of
this front in Nebraska and bufr soundings the cloud bases are
expected to range from 1000 to 1500 feet.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 68 21 29 10 / 0 0 0 20
GCK 67 21 27 9 / 0 0 0 30
EHA 68 21 27 11 / 0 0 0 30
LBL 71 23 30 12 / 0 0 0 30
HYS 62 21 29 10 / 0 0 0 20
P28 66 29 36 16 / 0 0 0 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Gerard
LONG TERM...JJohnson
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1248 PM EST TUE DEC 3 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 341 AM EST TUE DEC 3 2013
A WARM FRONT MOVING THROUGH LOWER MICHIGAN WILL BRING LIGHT SNOW
POSSIBLY MIXED WITH SLEET AND FREEZING RAIN THIS MORNING. WE DON/T
EXPECT MUCH IF ANY ACCUMULATION. HOWEVER A FEW ROADS COULD BECOME
SLICK. THE PCPN WILL BECOME LIGHT RAIN THIS AFTERNOON AS WARMER AIR
MOVES INTO THE REGION.
A STRONG COLD FRONT WILL MOVE THROUGH WEDNESDAY NIGHT BRINGING AN
ABRUPT END TO THE 50 DEGREE TEMPERATURES EXPECTED WEDNESDAY. SNOW
SHOWERS AND HIGHS IN THE 20S ARE EXPECTED FRIDAY THROUGH THE
WEEKEND.
&&
.UPDATE...
ISSUED AT 1154 AM EST TUE DEC 3 2013
I UPDATED THE GRIDS TO KEEP THE CHANCE OF FREEZING RAIN GOING INTO
THE EVENING NEAR ROUTE 10...EAST OF US-131 (OVER THE HIGHER
TERRAIN AREAS). ALSO I INCREASED THE CHANCE OF RAIN OVER SOUTHERN
AREAS ANOTHER SHORTWAVE HEADS INTO THE AREA THIS AFTERNOON. THIS
IS SEEN NICELY ON BOTH THE WATER VAPOR AND IR IMAGE LOOPS FROM MN
TO WI INTO IL AT 11 AM. AS THAT MOVES NORTH AND EAST IT SHOULD
SHOULD KEEP THE RAIN GOING NORTH OF ROUTE 2O INTO THE LATE
EVENING HOURS BUT ALLOW THE RAIN SHOULD END FOR AWHILE OVER AREAS
NEAR AND SOUTH OF I-96.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
FORECAST CONCERNS DEAL WITH MIXED PCPN MAINLY THIS MORNING.
LATEST RADAR SHOWS A BAND OF PCPN STRETCHING FROM OCEANA COUNTY
SOUTHEAST TOWARD NW OHIO MOVING NEED THROUGH THE CWA. MOST OF THIS
IS LIGHT SHOW BUT LOCAL OBS HAVE SHOWN SOME SLEET TOO. THIS WAS
CORROBORATED BY DUAL POL. LATEST HRRR AND FCST SOUNDINGS SUGGEST
SOME
LIGHT FREEZING RAIN IS POSSIBLE TOO THIS MORNING BEFORE TEMPS WARM
UP ENOUGH TO RESULT IN LIGHT RAIN. PCPN IS FAIRLY LIGHT AND ANY
ACCUMS SHOULD REMAIN LESS THAN AN INCH. THAT SAID...A FEW ROADS MAY
BECOME SLICK.
A WARM FRONT WILL CONTINUE TO PUSH NORTH THROUGH THE CWA TONIGHT. H8
TEMPS RISING TO 7C SHOULD RESULT IN SFC TEMPS IN THE 50S TOMORROW.
MODELS CONTINUE TO BE AT ODDS ON COLD FRONTAL TIMING. WE/LL BE
CONSISTENT THOUGH IN FOLLOWING THE SLOWER ECMWF DUE TO THE OCCLUDING
NATURE OF THE SYSTEM. THAT MEANS A FROPA WEDNESDAY NIGHT. HIGHS
THURSDAY WILL BE IN THE MID 30S. LIGHT SNOW SHOWERS POSSIBLE
THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
TWO MAIN HEADLINES OF THE LONG TERM REMAIN THE COLD AND LAKE EFFECT
SNOW SHOWERS. THE COLD MAY BE THE BIGGER STORY AS THE LAKE EFFECT
LOOKS TO BE SOMEWHAT MOISTURE DEPLETED.
COLD AIR ADVECTION WILL BE IN FULL SWING THURSDAY NIGHT AS WE BEGIN
THE LONG TERM WITH THE LOW MOVING AWAY ACROSS ONTARIO. DELTA T/S
WILL BE IN THE MIDDLE TEENS...PROVIDING DECENT INSTABILITY. MOISTURE
LOOKS LIMITED SO NOT EXPECTING ANYTHING IN THE WAY OF SIGNIFICANT
LAKE EFFECT. MINOR ACCUMULATIONS AT BEST.
THAT REALLY REMAINS THE CASE FOR FRIDAY THROUGH SATURDAY. CONTINUED
COLD AIR ADVECTION WILL PUSH DELTA T/S INTO THE LOWER 20S C...BUT
MOISTURE REMAINS A LIMITING FACTOR. WE NEVER DEEPLY PLUNGE INTO
CYCLONIC FLOW TO THE NORTH SIDE OF THE UPPER JET AXIS...INSTEAD
REMAINING IN A BROAD SOUTHWEST TO WEST FLOW. 1000-700MB RH VALUES
FROM FRIDAY THROUGH SATURDAY REMAIN IN THE 40-60 PCT RANGE WHICH IS
NOT IDEAL. 20-40 PCT CHANCES FOR SNOW SHOWERS THURSDAY NIGHT THROUGH
SATURDAY SEEM WARRANTED. AT THIS POINT NOT EXPECTING ANY BIG
ACCUMULATIONS...JUST PERSISTENT LIGHT SNOW SHOWERS.
LOW PRESSURE IS FORECAST BY THE ECMWF (STILL THE MODEL OF CHOICE
TONIGHT) TO SWING NORTH THROUGH THE AREA SUNDAY NIGHT INTO MONDAY
WHICH BRINGS A GENERAL LIGHT SYNOPTIC SNOW TO THE AREA.
LOWS IN THE TEENS THROUGH THE PERIOD WITH HIGHS IN THE 20S WILL BE
COMMON. THIS IS COLDER THAN NORMAL...BUT BY NO MEANS RARE FOR EARLY
DECEMBER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1242 PM EST TUE DEC 3 2013
WITH A WARM FRONT ACROSS THE REGION PUSHING ONLY SLOWLY
NORTH...LOTS OF IFR CONDITIONS ALONG WITH RA/DZ WERE REPORTED FROM
THE TAF SITES. AS THIS FRONT WILL LINGER OVER THE AREA INTO
TONIGHT...THE LOW CONDITIONS WILL LIKELY PERSIST. SOME POCKETS OF
MVFR WILL BE POSSIBLE...BUT THEY SHOULD FILL IN QUICKLY SO THAT IS
NOT FEATURED IN THE FORECAST.
AS THE ARCTIC FRONT APPROACHES FROM THE WEST WED...THE LOW CLOUDS
WILL LIKELY LINGER. FOG COULD EVEN BECOME THICKER SENDING
CONDITIONS TO LIFR.
TEMPERATURES HAVE WARMED UP ENOUGH TO LIMIT THE RISK FOR SURFACE
BASED ICING AT KMKG...KGRR AND KLAN. HOWEVER JUST TO THE NORTH IN
PLACES LIKE KAMN AND KRQB ICING AND OR SNOW COULD CAUSE IMPACTS.
&&
.MARINE...
ISSUED AT 341 AM EST TUE DEC 3 2013
SOUTH TO SOUTHEAST WINDS WILL INCREASE TO 15 TO 25 KNOTS TODAY. THE
OFFSHORE NATURE OF THE WINDS SHOULD PRECLUDE WAVES FROM GETTING
HIGHER THAN 3 FEET.
&&
.HYDROLOGY...
ISSUED AT 341 AM EST TUE DEC 3 2013
NO HYDRO ISSUES TODAY. HOWEVER THE ARCTIC AIR EXPECTED BY THE END OF
THE WEEK COULD CAUSE ICE TO DEVELOP ON STREAMS AND RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...MJS
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1229 PM EST TUE DEC 3 2013
.UPDATE...
ISSUED AT 739 AM EST TUE DEC 3 2013
OPTED TO ADD SOME PATCHY -FZDZ TO THE FCST FOR LATER THIS MRNG/AFTN
FOR MUCH OF THE W HALF OF UPR MM WITH EXPECTATION THAT MID LVL
DRYING ASSOCIATED WITH DNVA/LARGER SCALE QVECTOR DVGC IN THE WAKE OF
DEPARTING SHRTWV WL DRY OUT THE DGZ LYR IN THE 10-12K FT RANGE. SFC
OBS IN NCENTRAL WI SHOW SOME OF THIS PCPN THERE...SO CONFIDENCE IS
INCREASED THIS WL HAPPEN AS WELL IN THE CWA WITH THE ONSET OF MID
LVL DRYING. EXCLUDED THIS PTYPE OVER THE FAR W WHERE LLVL E-SE FLOW
DOWNSLOPES/DRIES AND OVER THE E HALF WHERE LLVL DRY AIR HAS PROVEN
TO BE MORE RESILIENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 447 AM EST TUE DEC 3 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW RELATIVELY WEAK
ZONAL FLOW ALF OVER THE UPR GRT LKS TO THE N OF FASTER POLAR JET
OVER THE SRN 2/3 OF THE CONUS. THERE ARE 2 SHRTWVS OF NOTE EMBEDDED
IN THIS FLOW. THE FIRST IS MOVING E THRU MN AND CAUSING A BAND OF SN
EXTENDING FM NE MN SEWD OVER WRN LK SUP AND INTO CENTRAL WI AS OF
06Z UNDER AREA OF H85-5 QVECTOR CNVGC. THE AXIS OF HIER
REFLECTIVITIES IN WI APPEARS TO BE ORIENTED ALONG THE MOST
IMPRESSIVE ISENTROPIC ASCENT SHOWN ON THE 290K SFC /H7-75/...WHILE
THE MOST IMPRESSIVE RETURNS IN NE MN ALIGN WITH MOST VIGOROUS H85-5
QVECTOR CNVGC. THE 00Z INL/MPX RAOBS SHOW DEEP MSTR THRU THE DEPTH
OF THE TROP. ELY FEED OF DRIER LLVL AIR ASSOCIATED WITH AREA OF
MOCLR SKIES/HI PRES RDG AXIS STILL OVER FAR ERN UPR MI AND LOCATION
OF SHARPER H85 THERMAL PACKING/ISENTROPIC ASCENT TO THE S HAS SO FAR
LIMITED THE ENE EXTENT OF THE PCPN INTO UPR MI...BUT SN APPEARS
POISED TO SPREAD INTO THE WRN CWA PER LATEST SFC OBS/RADAR IMAGERY.
THE VSBY AT IWD FELL UNDER 2 MILES AT 07Z...AND THE VSBY AS CLOSE AS
ASHLAND IN NW WI IS DOWN TO 1/2 MILE. ENE FLOW DOWN WRN LK SUP MAY
BE ENHANCING THE SN INTO THIS AREA. IN THE AREA OVER WRN MN/MUCH OF
THE DAKOTAS UNDER DNVA/DEEP LYR QVECTOR DVGC BEHIND THE MN SHRTWV...
THERE IS LTL IF ANY PCPN FALLING EVEN THOUGH SKIES REMAIN CLDY WITH
QUITE A BIT OF MID LVL DRYING ABV LLVL MSTR SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. FARTHER TO THE W...THE 2ND MORE IMPRESSIVE
SHRTWV OF INTEREST IS MOVING EWD THRU THE NRN ROCKIES. 12HR H3 HGT
FALLS UP TO 200M AND H3 WIND SPEEDS UP TO 100M IN THE ACCOMPANYING
JET CORE ARE ASSOCIATED WITH THIS MORE IMPRESSIVE DISTURBANCE.
MAIN FCST CONCERNS IN THE SHORT TERM PERIOD ARE POPS/EXPECTED SN
ACCUMS THRU THIS MRNG ASSOCIATED WITH THE FIRST SHRTWV IN MN AND
NEED FOR ANY HEADLINES. FOCUS FOR TNGT TURNS TO POPS AND SN AMOUNTS
THAT WL ACCOMPANY THE APRCH OF THE 2ND STRONGER SHRTWV.
TODAY...AS MN SHRTWV TRACKS TO THE E INTO PERSISTENT SFC RDG AXIS
JUST TO THE E OF UPR MI AND AWAY FM TROF DEEPENING OVER THE W...
AREA OF H85-5 QVECTOR CNVGC IS PROGGED TO DIMINISH SGNFTLY BY 18Z
WITH MID LVL DRYING UNDER DVLPG H85-5 QVECTOR DVGC. EXPECT THE HIER
POPS THIS MRNG OVER THE W AND SCENTRAL UNDER THE SHARPER H85-5
QVECTOR CVNGC/SHARPER 295K ISENTROPIC ASCENT/AREA OF H85-7 FGEN.
GIVEN PRESENCE OF 2.5G/KG SPECIFIC HUMIDITY AT THIS LVL...EXPECT UP
TO 3 INCHES OF SN FOR THE 6-9 HR PERIOD OVER THE SW HALF OF THE CWA.
SINCE THE SN IS LIKELY TO FALL A FOR CLOSER TO 12Z HRS AT IWD...UP
TO 4 INCHES MAY ACCUMULATE THERE BEFORE THE PCPN DIMINISHES TOWARD
NOON. ALTHOUGH THE DGZ IS RATHER NARROW...MODELS SHOW FAIRLY
IMPRESSIVE OMEGA IN THIS LYR THAT MAY INCH SN/WATER RATIOS CLOSER
TO 15:1. CONSIDERING THE LO VSBYS REPORTED AT ASHLAND IN THE ABSENCE
OF LAKE ENHANCEMENT WITH THE LARGER SCALE E WIND...OPTED TO ISSUE A
WINTER WX ADVY FOR GOGEBIC COUNTY THRU MID MRNG. OTRW...UPSLOPE E
WIND OFF LK MI MAY CAUSE STEADIER SN TO LINGER LONGER OVER THE
SCENTRAL. SN WL LIKELY MOVE INTO THE E DURING THE AFTN BUT WL BE MUCH
LIGHTER AS THE DYNAMIC SUPPORT FADES AND HITS DRIER AIR.
TNGT...ALTHOUGH THE EARLY EVNG WL FEATURE DNVA/LARGER SCALE QVECTOR
DVGC LEFT IN THE WAKE OF THE DEPARTING/WEAKENING SHRTWV...FAVORED
CNDN MODEL SHOWS AXIS OF SHARPER H85-7 FGEN SUPPORTING BAND OF SN
NOW OVER SDAKOTA IMPACTING MAINLY THE SRN CWA FOR A COUPLE HRS IN
THE LATER EVNG. THE 00Z GFS/ECWMF SHOW A SIMILAR QPF...SO WENT FOR
HI END LIKELY POPS IN THIS AREA BY LATER IN THE EVNG. OVERALL MODEL
QPF UP TO 0.25 INCH WL SUPPORT A FEW INCHES OF SN IN THIS AREA. HIER
POPS/MORE SN MAY ARRIVE LATE OVER THE W AS THE DYNAMICS IN ADVANCE
OF THE SHRTWV MOVING THRU THE NRN ROCKIES PUSH TOWARD THE AREA. BUT
MODELS DISAGREE ON THE TIMING OF THE ARRIVAL OF THE DEEP LYR QVECTOR
CNVGC AS WELL AS INTENSITY OF THE SFC LO THAT MIGHT ACCOMPANY THE
LARGER SCALE FORCING. THE NAM/LOCAL WRF-ARW MODELS ARE THE MOST
AGGRESSIVE AT DEEPENING THE SFC LO AND BRINGING MORE PCPN FARTHER E.
BUT SINCE THE MAIN SHRTWV REMAINS SO FAR TO THE W THRU THE NGT...
SUSPECT THE SLOWER/WEAKER CNDN MODEL IS ON THE RIGHT TRACK. SO WENT
NO HIER THAN LIKELY POPS OVER THE FAR W FOR NOW. THE THERMAL FIELDS
FM THE CNDN MODEL INDICATE ENUF WARM AIR WL ARRIVE TO CAUSE THE SN
TO MIX WITH RA OVER THE FAR SCENTRAL.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EST TUE DEC 3 2013
CONTINUED CHALLENGING FORECAST IN STORE FOR WEDNESDAY THROUGH
WEDNESDAY NIGHT TIME FRAME AS A WINTER WEATHER SYSTEM TAKES AIM AT
THE UPPER GREAT LAKES. VERY COLD AIR IS EXPECTED TO BUILD IN ON THE
BACK SIDE OF THIS SYSTEM ALLOWING FOR VERY COLD TEMPERATURES FRIDAY
NIGHT THROUGH SATURDAY NIGHT.
WEDNESDAY INTO WEDNESDAY NIGHT...SITUATION LOOKS A BIT BETTER FROM A
FORECASTING STANDPOINT AS MODELS ARE COMING INTO BETTER AGREEMENT
WITH RESPECT TO THE HANDLING OF THE LOW PRESSURE SYSTEM POISED TO
AFFECT THE AREA THROUGH THIS TIME PERIOD. THE 00Z RUN OF THE NAM AND
GFS ARE FINALLY ALIGNING BETTER WITH THE MORE CONSISTENT
EC/GEM...ALTHOUGH THEY ARE A TOUCH FASTER AT SHIFTING THE LOW INTO
THE UPPER PENINSULA. AS OF 12Z/04 EACH OF THE MODELS ARE IN GOOD
AGREEMENT IN PLACING THE SURFACE LOW OVER SW WISCONSIN WITH VERY
SIMILAR INTENSITIES. THE UPPER LEVEL 500MB CLOSED LOW IS PROGGED TO
BE POSITIONED FARTHER NORTHWEST OVER NORTHWESTERN MN...INDICATING
THE POTENTIAL FOR ADDITIONAL INTENSIFICATION OF THE SURFACE LOW. AT
THAT TIME ISENTROPIC UPGLIDE IS EXPECTED TO CONTINUE AS SHOWN BY
ANALYZING MOISTURE AND MOISTURE TRANSPORT ON A 295K PRESSURE
ISOSURFACE. SOUNDINGS AROUND 12Z/04 INDICATE THAT MOST OF THE
PRECIPITATION EAST OF A MQT TO IMT LINE WILL LIKELY BE IN THE FORM
OF RAIN AS A FAIRLY DEEP WARM LAYER EXISTS IN THE BOUNDARY LAYER.
WEST OF THAT LINE ATMOSPHERIC PROFILES ARE SUCH THAT THE
PRECIPITATION SHOULD REMAIN IN THE FORM OF SNOW. ALSO AT THIS TIME
FORCING IN THE DGZ SEEMS FAIRLY LIMITED...HOWEVER...THIS WILL CHANGE
THROUGH THE DAY. THE LOW IS PROGGED TO BE OVER SOUTH CENTRAL WI BY
18Z/04. AS THIS LOW CONTINUES TO APPROACH DURING THIS TIME PERIOD
INCREASED MOISTURE AND FORCING IN THE DGZ IS EXPECTED TO INCREASE
ALLOWING FOR A STEADY INCREASE IN SNOWFALL INTENSITY DURING THE
AFTERNOON HOURS. BETWEEN 00Z/05 AND 06Z/05 THE LOW IS PROGGED TO
SHIFT NORTH AND EASTWARD INTO THE EAST CENTRAL PORTION OF THE UPPER
PENINSULA. INCREASED SNOWFALL RATES ARE EXPECTED TO CONTINUE DURING
THAT TIME PERIOD AS WELL...AS CONTINUED MOISTURE AND LIFT ARE
PROGGED TO BE COLLOCATED IN THE DGZ AS SHOWN BY ANALYZING 1000-500MB
RH AS WELL AS QCONV IN THE 700-500 DGZ LAYER AS IDENTIFIED USING
ATMOSPHERIC PROFILES OF THE EC/GEM. THE WESTERN HALF OF THE UPPER
PENINSULA LOOKS TO ALSO BE IN A FAVORED LOCATION FOR HEAVY SNOWFALL
AS THIS REGION IS IN THE FAVORED LEFT EXIT REGION OF AN UPPER LEVEL
JET. THE MAIN CAVEAT HERE IS THE NEW UNCERTAINTY WITH PRECIPITATION
TYPE WHICH WAS INTRODUCED BY THE 00Z EC/GEM/UKMET WHICH PULLS THE
SURFACE LOW MUCH FARTHER TO THE WEST...WHICH TAKES THE LOW VERY NEAR
WHERE THE PREVIOUS GFS MODELS WERE TAKING IT OVER THE PAST COUPLE OF
DAYS. THIS WOULD SHIFT THE RAIN SNOW LINE FARTHER WEST...POSSIBLY
REDUCING SNOWFALL TOTALS. HAVE DECIDED TO CONTINUE WITH AN UPDATED
SPS BASED ON COORDINATION WITH SURROUNDING OFFICES...AS CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO GO WITH A HEADLINE.
THURSDAY THROUGH SATURDAY...BETWEEN 12Z/05 AND 18Z/05 THE SURFACE
LOW IS PROGGED TO SHIFT NORTHEASTWARD TO JUST SOUTH OF JAMES
BAY...TAKEN THE BETTER SYNOPTIC FORCING OUT OF THE AREA. AT THE SAME
TIME A DEEP TROUGH DIGGING INTO THE NORTHERN PLAINS WILL BEGIN TO
INFLUENCE THE WEATHER IN THE UPPER PENINSULA. WINDS WILL BECOME
WESTERLY TO WEST NORTHWESTERLY IN THE RETURN FLOW ON THE BACK SIDE
OF THE LOW PRESSURE SYSTEM. THIS WILL ALLOW LAKE EFFECT SNOW DEVELOP
IN THE SNOWBELTS FAVORED WITH THE SAID WIND DIRECTION. 850MB
TEMPERATURES ARE EXPECTED TO DROP FROM NEAR -14C 12/05 TO AROUND
-22C 12Z/07. THESE TEMPERATURES ARE MORE THAN FAVORABLE FOR LES
GIVEN LAKE SURFACE TEMPERATURES AROUND 4C TO 5C...CREATING DELTA T
VALUES BETWEEN 18 AND 27 DEGREES THROUGH THIS TIME PERIOD.
WINDS...AGAIN...LOOK TO BE FAVORABLE WITH SURFACE TO 850MB WINDS
REMAINING OUT OF THE WEST...AND WELL WITHIN THE 30 DEGREE TOLERANCE
FOR LES. IT APPEARS AS IF THE TIME FRAME FOR HEAVIER LES WOULD OCCUR
THURSDAY EVENING INTO FRIDAY MORNING AS INVERSION HEIGHTS INCREASE
TO AROUND 8-9KFT AFTER ADJUSTING FOR LAKE SURFACE TEMPERATURES. THE
MOISTURE IS COLLOCATED WITH THE DGZ WHICH WOULD BE MORE FAVORABLE
FOR SNOWFLAKE PRODUCTION. FRIDAY AFTERNOON THROUGH SATURDAY
INVERSION HEIGHTS ARE EXPECTED TO BECOME MORE SHALLOW AS
TEMPERATURES ALSO BEGIN TO RAPIDLY DROP AS THE NEXT TROUGH AXIS
PRESSES INTO THE AREA. THESE COLDER TEMPERATURES WILL PRESS THE DGZ
DOWN TO THE VERY LOWEST LEVELS OF THE ATMOSPHERE. WHILE IT IS LIKELY
THAT SNOW WILL CONTINUE TO FALL THROUGH THE FRIDAY AFTERNOON INTO
SATURDAY TIME PERIOD...SNOW PRODUCTION WILL BE LIMITED AS THE
MOISTURE IS MAINLY OUTSIDE OF THE DGZ. TEMPERATURES THIS WEEKEND
WILL BE WELL BELOW NORMAL WITH TEMPERATURES DROPPING INTO THE TEENS
BELOW ZERO FRIDAY NIGHT INTO SATURDAY NIGHT...ESPECIALLY OVER THE
WEST HALF. HIGH TEMPERATURES WILLS STRUGGLE TO GET OUT OF THE SINGLE
DIGITS OVER WESTERN AREAS. WIND CHILLS THIS WEEKEND WILL BECOME
DANGEROUSLY COLD WITH READINGS DROPPING TO AROUND 30 BELOW ZERO OVER
THE INTERIOR WEST.
SATURDAY NIGHT THROUGH MONDAY...A SURFACE HIGH PRESSURE SYSTEM IS
PROGGED TO MOVE INTO THE UPPER GREAT LAKES REGION AS UPPER LEVEL
FLOW BECOMES SLIGHTLY MORE ZONAL SATURDAY NIGHT THROUGH SUNDAY. THIS
ALONG WITH DRYER AIR WILL ALLOW LAKE EFFECT SNOT TO DIMINISH. LOW
PRESSURE WILL THEN BUILD BACK INTO THE AREA SUNDAY NIGHT INTO
MONDAY. WINDS WILL BECOME SOUTH TO SOUTHWESTERLY DURING THIS TIME
PERIOD WHILE TEMPERATURES ALOFT AT 850MB LINGER AROUND -15C WHICH
WILL HELP LES TO DEVELOP OVER THE FAR EASTERN UPPER PENINSULA AS THE
WIND FLOW WOULD BE DIRECTLY ACROSS THE WARM WATERS OF LAKE MICHIGAN.
THE BEST CHANCE OF THIS HAPPENING WOULD BE SUNDAY NIGHT INTO MONDAY
MORNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1228 PM EST TUE DEC 3 2013
VERY CHALLENGING FORECAST THIS AFTERNOON AND TOMORROW AS APPROACHING
LOW PRESSURE WITH SEVERAL UPPER LEVEL SHORTWAVES ARE EXPECTED TO
MOVE THROUGH THE AREA. THE MAIN QUESTION IS PRECIPITATION TYPE...AND
HOW LOW VISIBILITIES/CEILINGS WILL DIP DOWN. GENERALLY LIGHT SNOW
SHOWERS OVER NORTHERN WI AND WESTERN LAKE SUPERIOR WILL CONTINUE TO
MOVE THROUGH IWD THROUGH THE AFTERNOON...BUT VISIBILITIES SHOULD NOT
DIP TOO LOW GIVEN THE DOWNSLOPE WIND DIRECTION. SAW AND CMX WILL
CONTINUE TO SEE FLUCTUATING VISIBILITIES THROUGH MID AFTERNOON
TODAY...UNTIL A BRIEF BREAK IN MORE INTENSE PRECIPITATION ARRIVES.
OVERALL...HAVE IFR TO MVFR CONDITIONS THROUGH THE TIME PERIOD.
FOR THE LOW PRESSURE SYSTEM MOVING IN TONIGHT AND
TOMORROW...DIFFERENCES AMONGST MODELS ARE LEADING TO A DIFFICULT
FORECAST FOR PRECIPITATION TYPE. CURRENT THINKING IS THAT ACROSS
WESTERN UPPER MICHIGAN...FOR CMX/IWD THE PTYPE WILL BE PRIMARILY
SNOW. IF WARMER AIR WITH THE SYSTEM CAN REACH FURTHER NORTH AND
WESTWARD...THESE SITES MAY SEE FREEZING RAIN/SNOW MIX...BUT DID NOT
FEEL CONFIDENT ENOUGH TO PLACE INTO THE TAF AT THIS TIME. FOR
SAW...HAVE INCLUDED -RASN FOR NOW...BUT -FZRA COULD OCCUR IN THE
AFTERNOON AS TEMPERATURES WARM.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 AM EST TUE DEC 3 2013
EXPECT INCREASING E WINDS THRU TONIGHT AS THE PRES GRADIENT TIGHTENS
OVER THE UPPER LAKES BETWEEN HI PRES OVER NORTHERN ONTARIO AND LO
PRES TAKING SHAPE IN THE PLAINS. THE STRONGEST WINDS WILL BE OVER
WESTERN LAKE SUPERIOR...WHERE THE TERRAIN SURROUNDING THE LAKE
FUNNELS AND ENHANCES THE LARGER SCALE WINDS. MAINTAINED GOING GALE
WARNINGS FOR THE TWO WESTERN ZONES AND MENTIONED SOME GALE FORCE
GUSTS OVER THE CENTRAL AS WELL THIS AFTERNOON THRU TONIGHT.
LOW PRESSURE WILL MOVE ACROSS THE UPPER GREAT LAKES LATE WED THROUGH
THU MORNING. IN THE WAKE OF THE LOW...VERY COLD AIR ADVECTING OVER
THE RELATIVELY WARM WATERS WILL INCREASE INSTABILITY AND RESULT IN W
TO NW GALES AT TIMES FOR PORTIONS OF LAKE SUPERIOR WED NIGHT/THU.
CONTINUED FLOW OF VERY COLD AIR MAY RESULT IN A FEW GALE FORCE GUSTS
INTO SATURDAY BEFORE HIGH PRESSURE BUILDS IN SUNDAY. THIS HIGH
PRESSURE SYSTEM WILL MOVE DIRECTLY OVERHEAD BY SUNDAY AFTERNOON
ALLOW WINDS TO BECOME LIGHT AND VARIABLE. BUILDING WAVES AND THE
ARRIVAL OF THE ARCTIC AIR WILL CAUSE AN INCREASING FREEZING SPRAY
POTENTIAL FOR THE LAST HALF OF THE WORK WEEK AND INTO THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 AM EST /9 AM CST/ WEDNESDAY FOR LSZ162.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST WEDNESDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...KC
LONG TERM...KEC
AVIATION...MCD
MARINE...KC/KEC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1154 AM EST TUE DEC 3 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 341 AM EST TUE DEC 3 2013
A WARM FRONT MOVING THROUGH LOWER MICHIGAN WILL BRING LIGHT SNOW
POSSIBLY MIXED WITH SLEET AND FREEZING RAIN THIS MORNING. WE DON/T
EXPECT MUCH IF ANY ACCUMULATION. HOWEVER A FEW ROADS COULD BECOME
SLICK. THE PCPN WILL BECOME LIGHT RAIN THIS AFTERNOON AS WARMER AIR
MOVES INTO THE REGION.
A STRONG COLD FRONT WILL MOVE THROUGH WEDNESDAY NIGHT BRINGING AN
ABRUPT END TO THE 50 DEGREE TEMPERATURES EXPECTED WEDNESDAY. SNOW
SHOWERS AND HIGHS IN THE 20S ARE EXPECTED FRIDAY THROUGH THE
WEEKEND.
&&
.UPDATE...
ISSUED AT 1154 AM EST TUE DEC 3 2013
I UPDATED THE GRIDS TO KEEP THE CHANCE OF FREEZING RAIN GOING INTO
THE EVENING NEAR ROUTE 10...EAST OF US-131 (OVER THE HIGHER
TERRAIN AREAS). ALSO I INCREASED THE CHANCE OF RAIN OVER SOUTHERN
AREAS ANOTHER SHORTWAVE HEADS INTO THE AREA THIS AFTERNOON. THIS
IS SEEN NICELY ON BOTH THE WATER VAPOR AND IR IMAGE LOOPS FROM MN
TO WI INTO IL AT 11 AM. AS THAT MOVES NORTH AND EAST IT SHOULD
SHOULD KEEP THE RAIN GOING NORTH OF ROUTE 2O INTO THE LATE
EVENING HOURS BUT ALLOW THE RAIN SHOULD END FOR AWHILE OVER AREAS
NEAR AND SOUTH OF I-96.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
FORECAST CONCERNS DEAL WITH MIXED PCPN MAINLY THIS MORNING.
LATEST RADAR SHOWS A BAND OF PCPN STRETCHING FROM OCEANA COUNTY
SOUTHEAST TOWARD NW OHIO MOVING NEED THROUGH THE CWA. MOST OF THIS
IS LIGHT SHOW BUT LOCAL OBS HAVE SHOWN SOME SLEET TOO. THIS WAS
CORROBORATED BY DUAL POL. LATEST HRRR AND FCST SOUNDINGS SUGGEST
SOME
LIGHT FREEZING RAIN IS POSSIBLE TOO THIS MORNING BEFORE TEMPS WARM
UP ENOUGH TO RESULT IN LIGHT RAIN. PCPN IS FAIRLY LIGHT AND ANY
ACCUMS SHOULD REMAIN LESS THAN AN INCH. THAT SAID...A FEW ROADS MAY
BECOME SLICK.
A WARM FRONT WILL CONTINUE TO PUSH NORTH THROUGH THE CWA TONIGHT. H8
TEMPS RISING TO 7C SHOULD RESULT IN SFC TEMPS IN THE 50S TOMORROW.
MODELS CONTINUE TO BE AT ODDS ON COLD FRONTAL TIMING. WE/LL BE
CONSISTENT THOUGH IN FOLLOWING THE SLOWER ECMWF DUE TO THE OCCLUDING
NATURE OF THE SYSTEM. THAT MEANS A FROPA WEDNESDAY NIGHT. HIGHS
THURSDAY WILL BE IN THE MID 30S. LIGHT SNOW SHOWERS POSSIBLE
THURSDAY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 341 AM EST TUE DEC 3 2013
TWO MAIN HEADLINES OF THE LONG TERM REMAIN THE COLD AND LAKE EFFECT
SNOW SHOWERS. THE COLD MAY BE THE BIGGER STORY AS THE LAKE EFFECT
LOOKS TO BE SOMEWHAT MOISTURE DEPLETED.
COLD AIR ADVECTION WILL BE IN FULL SWING THURSDAY NIGHT AS WE BEGIN
THE LONG TERM WITH THE LOW MOVING AWAY ACROSS ONTARIO. DELTA T/S
WILL BE IN THE MIDDLE TEENS...PROVIDING DECENT INSTABILITY. MOISTURE
LOOKS LIMITED SO NOT EXPECTING ANYTHING IN THE WAY OF SIGNIFICANT
LAKE EFFECT. MINOR ACCUMULATIONS AT BEST.
THAT REALLY REMAINS THE CASE FOR FRIDAY THROUGH SATURDAY. CONTINUED
COLD AIR ADVECTION WILL PUSH DELTA T/S INTO THE LOWER 20S C...BUT
MOISTURE REMAINS A LIMITING FACTOR. WE NEVER DEEPLY PLUNGE INTO
CYCLONIC FLOW TO THE NORTH SIDE OF THE UPPER JET AXIS...INSTEAD
REMAINING IN A BROAD SOUTHWEST TO WEST FLOW. 1000-700MB RH VALUES
FROM FRIDAY THROUGH SATURDAY REMAIN IN THE 40-60 PCT RANGE WHICH IS
NOT IDEAL. 20-40 PCT CHANCES FOR SNOW SHOWERS THURSDAY NIGHT THROUGH
SATURDAY SEEM WARRANTED. AT THIS POINT NOT EXPECTING ANY BIG
ACCUMULATIONS...JUST PERSISTENT LIGHT SNOW SHOWERS.
LOW PRESSURE IS FORECAST BY THE ECMWF (STILL THE MODEL OF CHOICE
TONIGHT) TO SWING NORTH THROUGH THE AREA SUNDAY NIGHT INTO MONDAY
WHICH BRINGS A GENERAL LIGHT SYNOPTIC SNOW TO THE AREA.
LOWS IN THE TEENS THROUGH THE PERIOD WITH HIGHS IN THE 20S WILL BE
COMMON. THIS IS COLDER THAN NORMAL...BUT BY NO MEANS RARE FOR EARLY
DECEMBER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 711 AM EST TUE DEC 3 2013
AVIATION CONDITIONS SHOULD CONTINUE TO DETERIORATE THE NEXT 24
HOURS...WITH WIDESPREAD IFR EXPECTED THIS AFTERNOON. OVERNIGHT
MOST SITES SHOULD SEE CEILINGS DROP FURTHER...INTO LIFR.
A MIXTURE OF PRECIPITATION IS OCCURRING THIS MORNING AS WARMER AIR
SURGES INTO THE REGION ALOFT. SOME SNOW...SLEET AND FREEZING RAIN
MAY MIX IN FROM TIME TO TIME THROUGH 15Z OR SO. BY MIDDAY...ALL
PRECIPITATION SHOULD HAVE SWITCHED OVER TO RAIN. SCATTERED RAIN
SHOWERS WILL BE POSSIBLE THIS AFTERNOON AND EVENING.
CEILINGS SHOULD CONSISTENTLY LOWER THE NEXT 24 HOURS. FOG SHOULD
BECOME MORE PREVALENT WITH TIME...WITH IFR VISIBILITIES BECOMING
FAIRLY WIDESPREAD TONIGHT.
&&
.MARINE...
ISSUED AT 341 AM EST TUE DEC 3 2013
SOUTH TO SOUTHEAST WINDS WILL INCREASE TO 15 TO 25 KNOTS TODAY. THE
OFFSHORE NATURE OF THE WINDS SHOULD PRECLUDE WAVES FROM GETTING
HIGHER THAN 3 FEET.
&&
.HYDROLOGY...
ISSUED AT 341 AM EST TUE DEC 3 2013
NO HYDRO ISSUES TODAY. HOWEVER THE ARCTIC AIR EXPECTED BY THE END OF
THE WEEK COULD CAUSE ICE TO DEVELOP ON STREAMS AND RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1140 AM CST TUE DEC 3 2013
.UPDATE...
ISSUED AT 1034 AM CST TUE DEC 3 2013
LOTS OF STRATUS CONTINUES TO PUSH SOUTH ACROSS THE FORECAST AREA
THIS MORNING. WITH THIS STATUS MOVING IN...EXPECT TEMPERATURES TO
STRUGGLE TO CLIMB MUCH AFTER THE SKIES CLOUD OVER...AND
CORRESPONDINGLY DROPPED AFTERNOON FORECAST TEMPERATURES
SIGNIFICANTLY ACROSS THE ENTIRE AREA. STUCK FAIRLY CLOSE TO A
BLEND OF PREVIOUS FORECAST AND RAP MODEL...WHICH MAY ACTUALLY BE
TOO OPTIMISTIC FROM AROUND I80 SOUTH TO THE NE/KS STATE LINE...WHERE
STRATUS CONTINUES TO RAPIDLY ENCROACH A BIT FASTER THAN PREVIOUSLY
THOUGHT.
UPDATE ISSUED AT 628 AM CST TUE DEC 3 2013
SENT ANOTHER UPDATE TO LOWER HIGH TEMPS AND HOURLY TEMPS FURTHER
FROM LEXINGTON-ORD IN COORDINATION WITH LBF.
UPDATE ISSUED AT 603 AM CST TUE DEC 3 2013
WITH THE INITIAL FCST ISSUANCE AT 4 AM...WAS UNSURE WHY THE
00Z/06Z NAM TEMPS WERE FCST TO BEHAVE THE WAY THEY WERE DEPICTED
AND NOW IT IS CLEAR AS WE SEE STRATUS SURGING S ACROSS CNTRL NEB.
THE SKY FCST HAS BEEN ENHANCED BY USING THE 13 KM RAP WHICH HAS AN
EXCELLENT HANDLE ON THE STRATUS...EVEN DEPICTING ITS LEADING EDGE
ERODING AROUND MIDDAY. HAVE ALSO REPLACED THE PREVIOUS HIGH TEMP
FCST BY A 50-50 BLEND THE 00Z/06Z NAM 2M TEMPS. THIS HAS COOLED
FCST HIGHS ALONG THE I-80 CORRIDOR NORTHWARD.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CST TUE DEC 3 2013
...AN EXTENDED PERIOD OF HARSH WINTER COLD IS ON THE DOORSTEP AND
ONCE IT ARRIVES TONIGHT THERE ARE NO SIGNS OF IT RELEASING UNTIL
MID-MONTH APPROACHES...
ALOFT: THE COLD CORE ARCTIC LOW THAT WAS OVER SIBERIA 7 DAYS AGO
IS NOW ON OUR DOORSTEP /CURRENTLY OVER MT/. WESTERLY FLOW WILL
BECOME SW AS THE LOW BECOMES ELONGATED AND OPENS UP...EJECTING A
SHORTWAVE TROF ACROSS THE NRN PLAINS THIS AFTERNOON AND TONIGHT.
SFC: THE ARCTIC COLD FRONT WAS ALONG THE SD-NEB BORDER...WITH A
PRE-FRONTAL TROF EXTENDING E-W ACROSS NEB. BOTH OF THESE FEATURES
TO PRESS S...CROSSING THE FCST AREA BETWEEN 2 PM AND 8 PM.
BITTERLY COLD HIGH PRES OVER THE CANADIAN ROCKIES BEGINS BUILDING
IN TONIGHT. A LEE-SIDE LOW WILL MIGRATE DOWN THE FRONT RANGE
TODAY AND THEN EJECT ACROSS OK TONIGHT. THIS WILL MAINTAIN A
TIGHT PRES GRADIENT.
HI-RES MESOSCALE MODELS SUGGEST THE FOLLOWING APPROXIMATE TIMES
OF FRONTAL PASSAGE:
3 PM ORD-LEXINGTON
4 PM OSCEOLA-KEARNEY-ELWOOD
5 PM YORK-FRANKLIN-LONG ISLAND KS
6 PM GENEVA-SMITH CENTER KS-PHILLIPSBURG KS
7 PM MANKATO-OSBORNE-STOCKTON
8 PM BELOIT
EARLY THIS MORNING: A BATCH OF MULTI-LAYERED MID-HIGH CLOUDS WAS
MOVING THRU THE FCST AREA. CLOUD TOPS WERE WARMING. UEX/LNX
RADARS HAVE SHOWN SOME SMALL POCKETS OF PRECIP...BUT SUB-CLOUD
AIR IS TOO DRY FOR ANYTHING TO SURVIVE TO THE SURFACE.
TODAY: ONCE THE BATCH OF CLOUDS DEPARTS TO THE E...WE COULD SEE A
PERIOD OF SUBSTANTIAL SUNSHINE. LOOK FOR A RAPID WARM-UP. THIS
WILL BE THE LAST DAY OF MUCH WARMER THAN NORMAL TEMPS. HIGHS ARE
PRIMARILY BASED ON THE 21Z/2 BIAS CORRECTED SREF.
THE SATELLITE FOG/REFLECTIVITY PRODUCT SHOWS STRATUS OVERCAST
IMMEDIATELY BEHIND T HE FRONT. IT IS DISCONCERTING TO SEE IT
DROPPING INTO NRN NEB. THIS WILL NEED TO BE MONITORED AS
SUBSTANTIAL CHANGES WILL NEED TO OCCUR TO THE SHORT-TERM FCST.
THE 06Z NAM SUGGESTS THE STRATUS WILL DROP INTO AREAS N OF HWY
92...BUT THEN GET ERODED BY BOUNDARY LAYER MIXING.
POSSIBLE FCST SHORT-COMINGS: DO WE HAVE THE TIMING OF FRONTAL
PASSAGE CORRECT? THIS WILL HAVE SIGNIFICANT IMPLICATIONS ON THE
FCST. CONFIDENCE IN HOURLY TEMPS AND HIGHS ARE BELOW AVERAGE FROM
HWY 6 NORTHWARD.
IMMEDIATELY BEHIND THE FRONT EXPECT A RAPID INCREASE IN N WINDS
AND IT WILL CONTINUE THRU TONIGHT.
WIND: COOPERATIVE INSTITUTE FOR PRECIP SYSTEMS /CIPS/ TOP 10
ANALOGS OFFER A 50-60% CHANCE OF 30-35 KT WINDS. THE CHANCE FOR
36-40 KTS IS 30-40%. THE 00Z NAM HAS 30 KTS AS LOW AS 1000 FT AT
ORD WITH A MAX OF 32-34 KTS AVAILABLE AT THE TOP OF THE MIXED
LAYER. OVER THE REST OF S-CNTRL NEB 30 KTS IS FCST AS LOW AS 1500
FT WITH 32 KTS MAX. OVER N-CNTRL KS 30 KTS WILL BE AVAILABLE AT
THE TOP OF THE MIXED LAYER /2000 FT/. THIS MATCHES WELL WITH WHAT
IS OFFERED FROM THE CIPS ANALOGS. SO EXPECT THE HIGHEST GUSTS N OF
I-80...BUT THERE IS POTENTIAL FOR EVERYWHERE TO GUST TO 30 KTS
WITH THE HIGHEST PROBABILITY OVER S-CNTRL NEB. 06Z NAM CHECKED. IT
LOOKS A BIT MORE THREATENING WITH MAX GUSTS UP TO 35 KTS N OF HWY
6.
TONIGHT: CLOUDY WITH HARSH N WINDS. LOW TEMPS NEAR NORMAL.
AS FOR PRECIP TODAY-TONIGHT...A SHALLOW FRONTOGENETIC CIRCULATION
WILL NOT BE AIDED BY ANY DEEP-LAYER FORCING/LIFT. AND WHILE THE
LOW-LEVELS AND MID-LEVELS ABOVE 12K FT WILL BE AT OR NEAR
SATURATION ...THE 7-11K FT LAYER WILL BE DRY. SO PLAYED IT AS A
SLIGHT CHANCE FOR A LITTLE LIGHT RAIN/SNOW N OF HWY 92 LATE THIS
AFTERNOON AND A SLIGHT CHANCE OF LIGHT SNOW TONIGHT. BY 09Z...THE
BASE OF THE STRATUS WILL BECOME COLD ENOUGH FOR ICE TO FORM IN-
CLOUD. SO A SLIGHT CHANCE OF FLURRIES WAS INCLUDED FROM HWY 92
DOWN TO HWY 6 LATE TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CST TUE DEC 3 2013
GUIDANCE SUGGESTS A MID TO UPPER LEVEL LONG WAVE TROUGH WILL
EXTEND FROM CENTRAL CANADA...SOUTHWEST INTO THE WESTERN CONUS AT
12Z WEDNESDAY. THIS LONG WAVE TROUGH IS EXPECTED TO PERSIST OVER
THE SAME AREAS THROUGH 12Z FRIDAY...AT WHICH TIME IT SHOULD MOVE
EAST/NORTHEAST AND WEAKEN. A SECOND MID TO UPPER LEVEL LONGWAVE
TROUGH IS THEN EXPECTED TO DEVELOP OVER THE WESTERN CONUS SATURDAY
INTO SATURDAY NIGHT AND PERSIST THROUGH THE END OF THE LONG TERM
FORECAST PERIOD. RESULTANT MID TO UPPER LEVEL FLOW OVER OUR AREA
IS EXPECTED TO REMAIN FROM THE SOUTHWEST 12Z WEDNESDAY THROUGH 12Z
FRIDAY...WITH QUASI-ZONAL FLOW EXPECTED FRIDAY INTO FRIDAY
NIGHT...AND SOUTHWEST FLOW ONCE AGAIN SATURDAY THROUGH THE END OF
THE LONG TERM FORECAST PERIOD. A CLOSED MID LEVEL LOW...EMBEDDED
WITHIN THE FIRST LONG WAVE TROUGH...IS EXPECTED OVER THE NORTHERN
PLAINS AT 12Z WEDNESDAY...WITH THIS MID LEVEL LOW EXPECTED TO
EJECT TO THE NORTHEAST...AWAY FROM THE LONG WAVE TROUGH...INTO
ONTARIO AND QUEBEC BETWEEN 12Z WEDNESDAY AND 12Z FRIDAY. A
SECONDARY MID LEVEL LOW IS ALSO EXPECTED TO MOVE SOUTH AND THEN
EAST FROM SASKATCHEWAN INTO THE NORTHERN PLAINS BETWEEN 12Z
WEDNESDAY AND 12Z FRIDAY. THIS SECONDARY MID LEVEL LOW IS THEN
EXPECTED TO MOVE EAST/NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY
AND ONTARIO...ALONG WITH THE LONG WAVE TROUGH...FRIDAY INTO FRIDAY
NIGHT. THERE ARE THEN INDICATIONS OF A MID LEVEL SHORTWAVE
EJECTING FROM THE WESTERN CONUS AND MOVING EAST ACROSS PORTIONS OF
THE CENTRAL AND SOUTHERN PLAINS ON SUNDAY. AT THE SURFACE AN AREA
LOW BAROMETRIC PRESSURE IS EXPECTED OVER THE UPPER MISSISSIPPI
VALLEY AT 12Z WEDNESDAY...WITH AN ASSOCIATED LOW LEVEL BAROCLINIC
ZONE EXTENDING SOUTH/SOUTHWEST FROM THE LOW INTO THE MID
MISSISSIPPI VALLEY AND SOUTHERN PLAINS. STRONG SURFACE RIDGING
SHOULD BE WORKING INTO THE CENTRAL PLAINS ON WEDNESDAY AS THE
FIRST MID LEVEL LOW AND SURFACE LOW DEPART TO THE NORTHEAST. THE
SURFACE RIDGE SHOULD THEN PERSIST ACROSS THE CENTRAL PLAINS
THROUGH FRIDAY AS THE SECONDARY MID LEVEL LOW ADVANCES SOUTH AND
THEN EAST FROM SASKATCHEWAN...INDUCING A WEAK AREA OF LOW
BAROMETRIC PRESSURE AT THE SURFACE ACROSS PORTIONS OF THE UPPER
MISSISSIPPI VALLEY. LEE SIDE TROUGHING ALONG THE FRONT RANGE IS
THEN EXPECTED TO DEVELOP FRIDAY NIGHT INTO SATURDAY.
FINALLY...THERE IS A LIKELIHOOD A SURFACE LOW WILL MOVE EAST
SOMEWHERE ACROSS THE CENTRAL AND/OR SOUTHERN PLAINS DURING THE DAY
SUNDAY AS THE MID LEVEL SHORTWAVE DOES THE SAME. GIVEN ALL
THIS...LOW LEVEL FLOW SHOULD REMAIN FROM THE NORTH/NORTHWEST
WEDNESDAY FRIDAY...WITH SOUTHERLY FLOW EXPECTED SATURDAY...AND
ANOTHER ROUND OF NORTHWESTERLY LOW LEVEL FLOW TOWARDS THE END OF
THE FORECAST PERIOD.
ALTHOUGH THERE COULD BE A WEAK RIBBON OF MID LEVEL THERMAL
ADVECTION GRAZING OUR NORTHWEST DURING THE DAY WEDNESDAY...AT THIS
TIME IT APPEARS ANY SUBSTANTIAL OMEGA WILL REMAIN RELEGATED
NORTH/NORTHEAST AND WEST OF OUR AREA...EITHER IN CLOSER PROXIMITY
TO THE DEPARTING MID LEVEL LOW TO OUR NORTH/NORTHEAST OR IN CLOSER
PROXIMITY TO THE LONGWAVE TROUGH AXIS TO OUR WEST. WENT AHEAD WITH
DRY CONDITIONS ON WEDNESDAY AS A RESULT. HEADING INTO WEDNESDAY
NIGHT...THERE ARE INDICATIONS OF A ~90KT MID LEVEL JET STREAK
MOVING INTO THE MID MISSISSIPPI VALLEY...WITH THE RIGHT-REAR
QUADRANT OF THIS STREAK PERHAPS GENERATING ENOUGH OF A DIRECT
THERMAL CIRCULATION AND RESULTANT OMEGA FOR PRECIPITATION
PRODUCTION ACROSS PORTIONS OF OUR CWA. QPF FIELDS FROM THE
NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL SEEM TO SUGGEST OUR
WEST/SOUTHWEST CWA STAND THE BEST CHANCE AT OBSERVING MEASURABLE
PRECIPITATION. AS A RESULT...WENT AHEAD WITH ~20% POPS ACROSS OUR
WEST/SOUTHWEST 00Z-06Z THURSDAY. IT APPEARS THE MID LEVEL JET
STREAK WILL PERSIST THURSDAY INTO THURSDAY NIGHT AS WELL...HOWEVER
IT ALSO APPEARS THE JET STREAK AXIS WILL SHIFT EAST/SOUTHEAST
SOMEWHAT...THUS POSITIONING THE RIGHT-REAR QUADRANT AND RESULTANT
OMEGA SLIGHTLY SOUTH/SOUTHEAST OF OUR AREA AS WELL. ALTHOUGH SOME
GUIDANCE SUGGESTS OUR EXTREME SOUTH COULD OBSERVE MEASURABLE
PRECIPITATION AT ONE TIME OR ANOTHER THURSDAY AND THURSDAY
NIGHT...THERE REALLY IS NO AGREEMENT BETWEEN THE MODELS AS TO
WHETHER THIS WILL OCCUR THURSDAY...THURSDAY NIGHT...OR AT ALL.
ALTHOUGH WE PROBABLY CANNOT COMPLETELY RULE OUT A PERIOD OF VERY
LIGHT PRECIPITATION AT SOME POINT DURING THE THURSDAY-THURSDAY
NIGHT TIME PERIOD...GIVEN THE PRIMARY AXIS OF OMEGA APPEARS TO
REMAIN SOUTH/SOUTHEAST OF OUR AREA AND THE VERY LOW CONFIDENCE
THAT ANYONE WOULD ACTUALLY OBSERVE MEASURABLE
PRECIPITATION...OPTED TO REMOVE MEASURABLE PRECIPITATION FROM THE
THURSDAY-THURSDAY NIGHT TIME PERIOD AND INSTEAD GO AHEAD WITH A
MENTION OF SNOW FLURRIES. THE APPROACH OF THE MID LEVEL SHORTWAVE
SUNDAY COULD THEN BRING A CHANCE FOR PRECIPITATION SUNDAY.
ALLBLEND RESPONDED BY PROVIDING ~30% POPS TO THE AREA AND THESE
POPS WERE LEFT UNCHANGED FOR THE MOST PART.
FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM
AND OPERATIONAL GFS...SUGGEST AN INVASION OF ARCTIC AIR WILL KEEP
THE LOWER TROPOSPHERE COLD ENOUGH FOR SNOW PRODUCTION DURING THE
LONG TERM FORECAST PERIOD. ANY SNOWFALL THAT IS REALIZED ACROSS
OUR CWA WEDNESDAY NIGHT INTO THURSDAY SHOULD REMAIN VERY LIGHT.
THAT BEING SAID...THE VERY COLD/DRY LOWER TROPOSPHERE SUGGESTS
SNOW-WATER RATIOS WILL BE VERY HIGH...SOMEWHERE IN 20-30:1
RANGE...THUS EVEN A COUPLE HUNDREDTHS OF AN INCH OF LIQUID
PRECIPITATION...WHICH IS FORECAST ACROSS OUR WEST/SOUTHWEST 00-06Z
THURSDAY...COULD BE CAPABLE OF PRODUCING ~0.5" OF SNOWFALL. THE
MID LEVEL SHORTWAVE WHICH COULD POTENTIALLY IMPACT OUR AREA NEXT
SUNDAY IS SLIGHTLY MORE INTERESTING...WITH THE OPERATIONAL GFS AND
EC BOTH SUGGESTING SNOWFALL ACCUMULATION IN EXCESS OF AN INCH WILL
BE REALIZED ACROSS THE CWA. CERTAINLY SOMETHING TO CONTINUE
MONITORING.
ARCTIC AIR REMAINS POISED TO OCCUPY THE CENTRAL PLAINS DURING THE
LONG TERM FORECAST PERIOD. TEMPERATURES WITHIN THE SOURCE REGION
OF THE ARCTIC AIRMASS...CURRENTLY ACROSS PORTIONS OF
ALBERTA...SASKATCHEWAN AND MANITOBA...ONLY CLIMBED INTO THE TEENS
AND 20S MONDAY AFTERNOON...AND THESE VALUES ARE ALSO BEING
PRESENTED TO OUR AREA BY MULTIPLE SETS OF GUIDANCE THURSDAY
ONWARD. WEDNESDAY MAY ACTUALLY BE A TOUCH WARMER AS THE TRUE MASS
OF ARCTIC AIR WILL TAKE SOME TIME TO WORK INTO THE REGION...THUS
WEDNESDAY AFTERNOON HIGHS RANGING FROM THE 20S TO NEAR 30 ARE
FORECAST. BASED ON THE SOURCE REGION OF THE INCOMING ARCTIC AIR
MASS...IT APPEARS LIKELY OVERNIGHT LOWS IN THE SINGLE DIGITS WILL
ALSO BE COMMON THURSDAY ONWARD.
FINALLY...LATEST GUIDANCE SUGGESTS A SUSTAINED LOW LEVEL WIND
FIELD AT AROUND 15KTS...WORKING IN CONCERT WITH THE AFOREMENTIONED
SINGLE DIGIT OVERNIGHT LOWS...WILL PROVIDE APPARENT TEMPERATURE
VALUES BETWEEN -15 AND -19 DEGREES F ACROSS NORTHWESTERN PORTIONS
OF OUR CWA WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. WILL GO
AHEAD AND OUTLOOK THESE CONDITIONS IN THE HWO...PRIMARILY FOR
LOCATIONS ALONG AND NORTHWEST OF A LINE OF LEXINGTON...TO LOUP
CITY AND GREELEY. ALTHOUGH THESE VALUES DO NOT JUSTIFY ADVISORY
ISSUANCE...THIS WILL CERTAINLY NEED TO BE MONITORED THROUGH THE
NEXT COUPLE DAYS IN CASE HEADLINES BECOME NECESSARY. ALTHOUGH NOT
AS WIDESPREAD...APPARENT TEMPERATURE VALUES ARE ALSO FORECAST TO
APPROACH -15 DEGREES F ACROSS VALLEY AND GREELEY COUNTIES EARLY
FRIDAY MORNING AS WELL.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z WEDNESDAY
AFTERNOON) ISSUED AT 1135 AM CST TUE DEC 3 2013
IFR STRATUS AND NEAR MVFR VSBYS WILL CONTINUE AT THE TERMINAL
THROUGH THE AFTERNOON HOURS AS PLENTY OF STRATUS CONTINUES TO
STREAM IN FROM THE NORTH. WINDS WILL INCREASE SIGNIFICANTLY DURING
THE EVENING HOURS AS THE MAIN COLD FRONT PUSHES ACROSS THE
TERMINAL...AND THEN REMAIN ELEVATED...GUSTING TO 30 KTS OR
HIGHER...THROUGH THE AFTERNOON HOURS WEDNESDAY. MAY SEE SOME LIGHT
SNOW AT THE TERMINAL OVERNIGHT...BUT CONFIDENCE WAS LOW ENOUGH TO
LEAVE OUT OF THE TAF FOR THE TIME BEING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...ROSSI
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1038 AM CST TUE DEC 3 2013
.UPDATE...
ISSUED AT 1034 AM CST TUE DEC 3 2013
LOTS OF STRATUS CONTINUES TO PUSH SOUTH ACROSS THE FORECAST AREA
THIS MORNING. WITH THIS STATUS MOVING IN...EXPECT TEMPERATURES TO
STRUGGLE TO CLIMB MUCH AFTER THE SKIES CLOUD OVER...AND
CORRESPONDINGLY DROPPED AFTERNOON FORECAST TEMPERATURES
SIGNIFICANTLY ACROSS THE ENTIRE AREA. STUCK FAIRLY CLOSE TO A
BLEND OF PREVIOUS FORECAST AND RAP MODEL...WHICH MAY ACTUALLY BE
TOO OPTIMISTIC FROM AROUND I80 SOUTH TO THE NE/KS STATE LINE...WHERE
STRATUS CONTINUES TO RAPIDLY ENCROACH A BIT FASTER THAN PREVIOUSLY
THOUGHT.
UPDATE ISSUED AT 628 AM CST TUE DEC 3 2013
SENT ANOTHER UPDATE TO LOWER HIGH TEMPS AND HOURLY TEMPS FURTHER
FROM LEXINGTON-ORD IN COORDINATION WITH LBF.
UPDATE ISSUED AT 603 AM CST TUE DEC 3 2013
WITH THE INITIAL FCST ISSUANCE AT 4 AM...WAS UNSURE WHY THE
00Z/06Z NAM TEMPS WERE FCST TO BEHAVE THE WAY THEY WERE DEPICTED
AND NOW IT IS CLEAR AS WE SEE STRATUS SURGING S ACROSS CNTRL NEB.
THE SKY FCST HAS BEEN ENHANCED BY USING THE 13 KM RAP WHICH HAS AN
EXCELLENT HANDLE ON THE STRATUS...EVEN DEPICTING ITS LEADING EDGE
ERODING AROUND MIDDAY. HAVE ALSO REPLACED THE PREVIOUS HIGH TEMP
FCST BY A 50-50 BLEND THE 00Z/06Z NAM 2M TEMPS. THIS HAS COOLED
FCST HIGHS ALONG THE I-80 CORRIDOR NORTHWARD.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CST TUE DEC 3 2013
...AN EXTENDED PERIOD OF HARSH WINTER COLD IS ON THE DOORSTEP AND
ONCE IT ARRIVES TONIGHT THERE ARE NO SIGNS OF IT RELEASING UNTIL
MID-MONTH APPROACHES...
ALOFT: THE COLD CORE ARCTIC LOW THAT WAS OVER SIBERIA 7 DAYS AGO
IS NOW ON OUR DOORSTEP /CURRENTLY OVER MT/. WESTERLY FLOW WILL
BECOME SW AS THE LOW BECOMES ELONGATED AND OPENS UP...EJECTING A
SHORTWAVE TROF ACROSS THE NRN PLAINS THIS AFTERNOON AND TONIGHT.
SFC: THE ARCTIC COLD FRONT WAS ALONG THE SD-NEB BORDER...WITH A
PRE-FRONTAL TROF EXTENDING E-W ACROSS NEB. BOTH OF THESE FEATURES
TO PRESS S...CROSSING THE FCST AREA BETWEEN 2 PM AND 8 PM.
BITTERLY COLD HIGH PRES OVER THE CANADIAN ROCKIES BEGINS BUILDING
IN TONIGHT. A LEE-SIDE LOW WILL MIGRATE DOWN THE FRONT RANGE
TODAY AND THEN EJECT ACROSS OK TONIGHT. THIS WILL MAINTAIN A
TIGHT PRES GRADIENT.
HI-RES MESOSCALE MODELS SUGGEST THE FOLLOWING APPROXIMATE TIMES
OF FRONTAL PASSAGE:
3 PM ORD-LEXINGTON
4 PM OSCEOLA-KEARNEY-ELWOOD
5 PM YORK-FRANKLIN-LONG ISLAND KS
6 PM GENEVA-SMITH CENTER KS-PHILLIPSBURG KS
7 PM MANKATO-OSBORNE-STOCKTON
8 PM BELOIT
EARLY THIS MORNING: A BATCH OF MULTI-LAYERED MID-HIGH CLOUDS WAS
MOVING THRU THE FCST AREA. CLOUD TOPS WERE WARMING. UEX/LNX
RADARS HAVE SHOWN SOME SMALL POCKETS OF PRECIP...BUT SUB-CLOUD
AIR IS TOO DRY FOR ANYTHING TO SURVIVE TO THE SURFACE.
TODAY: ONCE THE BATCH OF CLOUDS DEPARTS TO THE E...WE COULD SEE A
PERIOD OF SUBSTANTIAL SUNSHINE. LOOK FOR A RAPID WARM-UP. THIS
WILL BE THE LAST DAY OF MUCH WARMER THAN NORMAL TEMPS. HIGHS ARE
PRIMARILY BASED ON THE 21Z/2 BIAS CORRECTED SREF.
THE SATELLITE FOG/REFLECTIVITY PRODUCT SHOWS STRATUS OVERCAST
IMMEDIATELY BEHIND T HE FRONT. IT IS DISCONCERTING TO SEE IT
DROPPING INTO NRN NEB. THIS WILL NEED TO BE MONITORED AS
SUBSTANTIAL CHANGES WILL NEED TO OCCUR TO THE SHORT-TERM FCST.
THE 06Z NAM SUGGESTS THE STRATUS WILL DROP INTO AREAS N OF HWY
92...BUT THEN GET ERODED BY BOUNDARY LAYER MIXING.
POSSIBLE FCST SHORT-COMINGS: DO WE HAVE THE TIMING OF FRONTAL
PASSAGE CORRECT? THIS WILL HAVE SIGNIFICANT IMPLICATIONS ON THE
FCST. CONFIDENCE IN HOURLY TEMPS AND HIGHS ARE BELOW AVERAGE FROM
HWY 6 NORTHWARD.
IMMEDIATELY BEHIND THE FRONT EXPECT A RAPID INCREASE IN N WINDS
AND IT WILL CONTINUE THRU TONIGHT.
WIND: COOPERATIVE INSTITUTE FOR PRECIP SYSTEMS /CIPS/ TOP 10
ANALOGS OFFER A 50-60% CHANCE OF 30-35 KT WINDS. THE CHANCE FOR
36-40 KTS IS 30-40%. THE 00Z NAM HAS 30 KTS AS LOW AS 1000 FT AT
ORD WITH A MAX OF 32-34 KTS AVAILABLE AT THE TOP OF THE MIXED
LAYER. OVER THE REST OF S-CNTRL NEB 30 KTS IS FCST AS LOW AS 1500
FT WITH 32 KTS MAX. OVER N-CNTRL KS 30 KTS WILL BE AVAILABLE AT
THE TOP OF THE MIXED LAYER /2000 FT/. THIS MATCHES WELL WITH WHAT
IS OFFERED FROM THE CIPS ANALOGS. SO EXPECT THE HIGHEST GUSTS N OF
I-80...BUT THERE IS POTENTIAL FOR EVERYWHERE TO GUST TO 30 KTS
WITH THE HIGHEST PROBABILITY OVER S-CNTRL NEB. 06Z NAM CHECKED. IT
LOOKS A BIT MORE THREATENING WITH MAX GUSTS UP TO 35 KTS N OF HWY
6.
TONIGHT: CLOUDY WITH HARSH N WINDS. LOW TEMPS NEAR NORMAL.
AS FOR PRECIP TODAY-TONIGHT...A SHALLOW FRONTOGENETIC CIRCULATION
WILL NOT BE AIDED BY ANY DEEP-LAYER FORCING/LIFT. AND WHILE THE
LOW-LEVELS AND MID-LEVELS ABOVE 12K FT WILL BE AT OR NEAR
SATURATION ...THE 7-11K FT LAYER WILL BE DRY. SO PLAYED IT AS A
SLIGHT CHANCE FOR A LITTLE LIGHT RAIN/SNOW N OF HWY 92 LATE THIS
AFTERNOON AND A SLIGHT CHANCE OF LIGHT SNOW TONIGHT. BY 09Z...THE
BASE OF THE STRATUS WILL BECOME COLD ENOUGH FOR ICE TO FORM IN-
CLOUD. SO A SLIGHT CHANCE OF FLURRIES WAS INCLUDED FROM HWY 92
DOWN TO HWY 6 LATE TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CST TUE DEC 3 2013
GUIDANCE SUGGESTS A MID TO UPPER LEVEL LONG WAVE TROUGH WILL
EXTEND FROM CENTRAL CANADA...SOUTHWEST INTO THE WESTERN CONUS AT
12Z WEDNESDAY. THIS LONG WAVE TROUGH IS EXPECTED TO PERSIST OVER
THE SAME AREAS THROUGH 12Z FRIDAY...AT WHICH TIME IT SHOULD MOVE
EAST/NORTHEAST AND WEAKEN. A SECOND MID TO UPPER LEVEL LONGWAVE
TROUGH IS THEN EXPECTED TO DEVELOP OVER THE WESTERN CONUS SATURDAY
INTO SATURDAY NIGHT AND PERSIST THROUGH THE END OF THE LONG TERM
FORECAST PERIOD. RESULTANT MID TO UPPER LEVEL FLOW OVER OUR AREA
IS EXPECTED TO REMAIN FROM THE SOUTHWEST 12Z WEDNESDAY THROUGH 12Z
FRIDAY...WITH QUASI-ZONAL FLOW EXPECTED FRIDAY INTO FRIDAY
NIGHT...AND SOUTHWEST FLOW ONCE AGAIN SATURDAY THROUGH THE END OF
THE LONG TERM FORECAST PERIOD. A CLOSED MID LEVEL LOW...EMBEDDED
WITHIN THE FIRST LONG WAVE TROUGH...IS EXPECTED OVER THE NORTHERN
PLAINS AT 12Z WEDNESDAY...WITH THIS MID LEVEL LOW EXPECTED TO
EJECT TO THE NORTHEAST...AWAY FROM THE LONG WAVE TROUGH...INTO
ONTARIO AND QUEBEC BETWEEN 12Z WEDNESDAY AND 12Z FRIDAY. A
SECONDARY MID LEVEL LOW IS ALSO EXPECTED TO MOVE SOUTH AND THEN
EAST FROM SASKATCHEWAN INTO THE NORTHERN PLAINS BETWEEN 12Z
WEDNESDAY AND 12Z FRIDAY. THIS SECONDARY MID LEVEL LOW IS THEN
EXPECTED TO MOVE EAST/NORTHEAST INTO THE UPPER MISSISSIPPI VALLEY
AND ONTARIO...ALONG WITH THE LONG WAVE TROUGH...FRIDAY INTO FRIDAY
NIGHT. THERE ARE THEN INDICATIONS OF A MID LEVEL SHORTWAVE
EJECTING FROM THE WESTERN CONUS AND MOVING EAST ACROSS PORTIONS OF
THE CENTRAL AND SOUTHERN PLAINS ON SUNDAY. AT THE SURFACE AN AREA
LOW BAROMETRIC PRESSURE IS EXPECTED OVER THE UPPER MISSISSIPPI
VALLEY AT 12Z WEDNESDAY...WITH AN ASSOCIATED LOW LEVEL BAROCLINIC
ZONE EXTENDING SOUTH/SOUTHWEST FROM THE LOW INTO THE MID
MISSISSIPPI VALLEY AND SOUTHERN PLAINS. STRONG SURFACE RIDGING
SHOULD BE WORKING INTO THE CENTRAL PLAINS ON WEDNESDAY AS THE
FIRST MID LEVEL LOW AND SURFACE LOW DEPART TO THE NORTHEAST. THE
SURFACE RIDGE SHOULD THEN PERSIST ACROSS THE CENTRAL PLAINS
THROUGH FRIDAY AS THE SECONDARY MID LEVEL LOW ADVANCES SOUTH AND
THEN EAST FROM SASKATCHEWAN...INDUCING A WEAK AREA OF LOW
BAROMETRIC PRESSURE AT THE SURFACE ACROSS PORTIONS OF THE UPPER
MISSISSIPPI VALLEY. LEE SIDE TROUGHING ALONG THE FRONT RANGE IS
THEN EXPECTED TO DEVELOP FRIDAY NIGHT INTO SATURDAY.
FINALLY...THERE IS A LIKELIHOOD A SURFACE LOW WILL MOVE EAST
SOMEWHERE ACROSS THE CENTRAL AND/OR SOUTHERN PLAINS DURING THE DAY
SUNDAY AS THE MID LEVEL SHORTWAVE DOES THE SAME. GIVEN ALL
THIS...LOW LEVEL FLOW SHOULD REMAIN FROM THE NORTH/NORTHWEST
WEDNESDAY FRIDAY...WITH SOUTHERLY FLOW EXPECTED SATURDAY...AND
ANOTHER ROUND OF NORTHWESTERLY LOW LEVEL FLOW TOWARDS THE END OF
THE FORECAST PERIOD.
ALTHOUGH THERE COULD BE A WEAK RIBBON OF MID LEVEL THERMAL
ADVECTION GRAZING OUR NORTHWEST DURING THE DAY WEDNESDAY...AT THIS
TIME IT APPEARS ANY SUBSTANTIAL OMEGA WILL REMAIN RELEGATED
NORTH/NORTHEAST AND WEST OF OUR AREA...EITHER IN CLOSER PROXIMITY
TO THE DEPARTING MID LEVEL LOW TO OUR NORTH/NORTHEAST OR IN CLOSER
PROXIMITY TO THE LONGWAVE TROUGH AXIS TO OUR WEST. WENT AHEAD WITH
DRY CONDITIONS ON WEDNESDAY AS A RESULT. HEADING INTO WEDNESDAY
NIGHT...THERE ARE INDICATIONS OF A ~90KT MID LEVEL JET STREAK
MOVING INTO THE MID MISSISSIPPI VALLEY...WITH THE RIGHT-REAR
QUADRANT OF THIS STREAK PERHAPS GENERATING ENOUGH OF A DIRECT
THERMAL CIRCULATION AND RESULTANT OMEGA FOR PRECIPITATION
PRODUCTION ACROSS PORTIONS OF OUR CWA. QPF FIELDS FROM THE
NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL SEEM TO SUGGEST OUR
WEST/SOUTHWEST CWA STAND THE BEST CHANCE AT OBSERVING MEASURABLE
PRECIPITATION. AS A RESULT...WENT AHEAD WITH ~20% POPS ACROSS OUR
WEST/SOUTHWEST 00Z-06Z THURSDAY. IT APPEARS THE MID LEVEL JET
STREAK WILL PERSIST THURSDAY INTO THURSDAY NIGHT AS WELL...HOWEVER
IT ALSO APPEARS THE JET STREAK AXIS WILL SHIFT EAST/SOUTHEAST
SOMEWHAT...THUS POSITIONING THE RIGHT-REAR QUADRANT AND RESULTANT
OMEGA SLIGHTLY SOUTH/SOUTHEAST OF OUR AREA AS WELL. ALTHOUGH SOME
GUIDANCE SUGGESTS OUR EXTREME SOUTH COULD OBSERVE MEASURABLE
PRECIPITATION AT ONE TIME OR ANOTHER THURSDAY AND THURSDAY
NIGHT...THERE REALLY IS NO AGREEMENT BETWEEN THE MODELS AS TO
WHETHER THIS WILL OCCUR THURSDAY...THURSDAY NIGHT...OR AT ALL.
ALTHOUGH WE PROBABLY CANNOT COMPLETELY RULE OUT A PERIOD OF VERY
LIGHT PRECIPITATION AT SOME POINT DURING THE THURSDAY-THURSDAY
NIGHT TIME PERIOD...GIVEN THE PRIMARY AXIS OF OMEGA APPEARS TO
REMAIN SOUTH/SOUTHEAST OF OUR AREA AND THE VERY LOW CONFIDENCE
THAT ANYONE WOULD ACTUALLY OBSERVE MEASURABLE
PRECIPITATION...OPTED TO REMOVE MEASURABLE PRECIPITATION FROM THE
THURSDAY-THURSDAY NIGHT TIME PERIOD AND INSTEAD GO AHEAD WITH A
MENTION OF SNOW FLURRIES. THE APPROACH OF THE MID LEVEL SHORTWAVE
SUNDAY COULD THEN BRING A CHANCE FOR PRECIPITATION SUNDAY.
ALLBLEND RESPONDED BY PROVIDING ~30% POPS TO THE AREA AND THESE
POPS WERE LEFT UNCHANGED FOR THE MOST PART.
FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE NAM
AND OPERATIONAL GFS...SUGGEST AN INVASION OF ARCTIC AIR WILL KEEP
THE LOWER TROPOSPHERE COLD ENOUGH FOR SNOW PRODUCTION DURING THE
LONG TERM FORECAST PERIOD. ANY SNOWFALL THAT IS REALIZED ACROSS
OUR CWA WEDNESDAY NIGHT INTO THURSDAY SHOULD REMAIN VERY LIGHT.
THAT BEING SAID...THE VERY COLD/DRY LOWER TROPOSPHERE SUGGESTS
SNOW-WATER RATIOS WILL BE VERY HIGH...SOMEWHERE IN 20-30:1
RANGE...THUS EVEN A COUPLE HUNDREDTHS OF AN INCH OF LIQUID
PRECIPITATION...WHICH IS FORECAST ACROSS OUR WEST/SOUTHWEST 00-06Z
THURSDAY...COULD BE CAPABLE OF PRODUCING ~0.5" OF SNOWFALL. THE
MID LEVEL SHORTWAVE WHICH COULD POTENTIALLY IMPACT OUR AREA NEXT
SUNDAY IS SLIGHTLY MORE INTERESTING...WITH THE OPERATIONAL GFS AND
EC BOTH SUGGESTING SNOWFALL ACCUMULATION IN EXCESS OF AN INCH WILL
BE REALIZED ACROSS THE CWA. CERTAINLY SOMETHING TO CONTINUE
MONITORING.
ARCTIC AIR REMAINS POISED TO OCCUPY THE CENTRAL PLAINS DURING THE
LONG TERM FORECAST PERIOD. TEMPERATURES WITHIN THE SOURCE REGION
OF THE ARCTIC AIRMASS...CURRENTLY ACROSS PORTIONS OF
ALBERTA...SASKATCHEWAN AND MANITOBA...ONLY CLIMBED INTO THE TEENS
AND 20S MONDAY AFTERNOON...AND THESE VALUES ARE ALSO BEING
PRESENTED TO OUR AREA BY MULTIPLE SETS OF GUIDANCE THURSDAY
ONWARD. WEDNESDAY MAY ACTUALLY BE A TOUCH WARMER AS THE TRUE MASS
OF ARCTIC AIR WILL TAKE SOME TIME TO WORK INTO THE REGION...THUS
WEDNESDAY AFTERNOON HIGHS RANGING FROM THE 20S TO NEAR 30 ARE
FORECAST. BASED ON THE SOURCE REGION OF THE INCOMING ARCTIC AIR
MASS...IT APPEARS LIKELY OVERNIGHT LOWS IN THE SINGLE DIGITS WILL
ALSO BE COMMON THURSDAY ONWARD.
FINALLY...LATEST GUIDANCE SUGGESTS A SUSTAINED LOW LEVEL WIND
FIELD AT AROUND 15KTS...WORKING IN CONCERT WITH THE AFOREMENTIONED
SINGLE DIGIT OVERNIGHT LOWS...WILL PROVIDE APPARENT TEMPERATURE
VALUES BETWEEN -15 AND -19 DEGREES F ACROSS NORTHWESTERN PORTIONS
OF OUR CWA WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. WILL GO
AHEAD AND OUTLOOK THESE CONDITIONS IN THE HWO...PRIMARILY FOR
LOCATIONS ALONG AND NORTHWEST OF A LINE OF LEXINGTON...TO LOUP
CITY AND GREELEY. ALTHOUGH THESE VALUES DO NOT JUSTIFY ADVISORY
ISSUANCE...THIS WILL CERTAINLY NEED TO BE MONITORED THROUGH THE
NEXT COUPLE DAYS IN CASE HEADLINES BECOME NECESSARY. ALTHOUGH NOT
AS WIDESPREAD...APPARENT TEMPERATURE VALUES ARE ALSO FORECAST TO
APPROACH -15 DEGREES F ACROSS VALLEY AND GREELEY COUNTIES EARLY
FRIDAY MORNING AS WELL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 603 AM CST TUE DEC 3 2013
TODAY: FOG/REFLECTIVITY SATELLITE IMAGERY SHOWS IFR STRATUS IS
SURGING S TOWARD GRI AT 12Z. ODX IS NOW OVC008 AND HAVE TIMED
THIS INTO GRI AT 14Z. THE STATISTICAL MODEL OUTPUT IS NOT HANDLING
THIS STRATUS. SO THIS FCST IS BASED ON CURRENT TRENDS AND MODEL RH
FIELDS...WHICH INDICATE THE LEADING EDGE OF THE STRATUS COULD
BEGIN ERODING AROUND MIDDAY...ALLOWING FOR A COUPLE HRS OF VFR
CIGS. IF THIS OCCURS...STRATUS WILL RE-INVADE AROUND 21Z WITH
FRONTAL PASSAGE. SHOULD SEE A SIGNIFICANT INCREASE IN N WINDS...
BUT THERE IS UNCERTAINTY ON IF ITS GRADUAL OR ABRUPT. CONFIDENCE:
AVERAGE
TONIGHT: STATISTICAL MODEL OUTPUT SUGGESTS MVFR CIGS...BUT CURRENT
OBS UPSTREAM ARE LARGELY IFR. THE TAF CIG IS MORE PESSIMISTIC THAN
MOS BUT NOT AS PESSIMISTIC AS CURRENT OBS UPSTREAM. BE AWARE THAT
CIGS MAY NEED TO BE DOWNGRADED A CATEGORY LATER TODAY. CONFIDENCE:
AVERAGE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...ROSSI
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS TULSA OK
352 PM CST TUE DEC 3 2013
.DISCUSSION...
WOW FOLKS...WHAT A FORECAST TODAY. THERE WILL BE SEVERAL ROUNDS OF
WINTRY PRECIPITATION THAT WILL HAVE IMPACTS ON TRAVEL AND POSSIBLY
THE POWER GRID AS WELL. I WILL DIVE INTO EACH FACET OF THE
FORECAST BELOW...ONE BY ONE.
FIRST...OF SOMEWHAT LESS IMPORTANCE...WILL BE FOG POTENTIAL
TONIGHT. FOR THE PAST 2 DAYS WE`VE HAD WIDESPREAD DENSE FOG.
TONIGHT...WHAT I SEE THAT IS DIFFERENT WILL BE THE DEPTH OF THE
NEAR GROUND MOIST LAYER. MODEL MOISTURE PROFILES DRY OUT FROM TOP
TO BOTTOM WITH TIME TONIGHT...ALTHOUGH THERE MAY BE ENOUGH REMNANT
MOISTURE NEAR THE GROUND FOR SOME PATCHY FOG DEVELOPMENT...SOME
POSSIBLY DENSE. FWIW...THE HRRR BREAKS OUT DENSE FOG OVER A GOOD
PORTION OF EASTERN OK THIS EVENING...AND IT HAS BEEN HANDLING THE
FOG WELL THE PAST 2 NIGHTS.
NOW TO THE MEAT OF THIS FORECAST. A VERY AMPLIFIED UPPER PATTERN
IS EVOLVING OVER THE WESTERN CONUS AS I TYPE...WITH A RIDGE NOSING
WELL UP INTO ALASKA...AND A DEEP POSITIVE TILT DOWNSTREAM TROUGH
DEVELOPING OVER THE WESTERN CONUS. THIS HAS CREATED A CROSS-POLAR
FLOW CLEAR FROM SIBERIA DOWN INTO NORTH AMERICA. WORSE YET...THIS
PATTERN WILL LIKELY PERSIST FOR ABOUT A WEEK...SENDING SHOT AFTER
SHOT OF ARCTIC AIR DOWN INTO THE CONUS AS DISTURBANCES ROTATE
AROUND THE POLAR VORTEX OVER CENTRAL CANADA. THE INITIAL SURGE OF
ARCTIC AIR WILL ARRIVE TOMORROW...AND WILL UNDERCUT A STRONG BELT
OF SW FLOW ALOFT DOWNSTREAM FROM THE WESTERN TROUGH. THE FIRST
ROUND OF PRECIP WILL BE FORCED MAINLY BY LOW TO MID LVL
FRONTOGENESIS...WHICH WILL KICK IN BY EARLY THURSDAY. THE MODELS
ARE IN VERY GOOD AGREEMENT ON A RATHER IMPRESSIVE BAND OF PRECIP
FROM SE OK UP INTO NRN AR ON THURSDAY. NE OK WILL BE ON THE FRINGE
OF THE BEST FN FORCING...AND WILL SEE LIGHTER PRECIP AMOUNTS AS A
RESULT. IN FACT...PORTIONS OF OSAGE COUNTY MAY NOT SEE ANYTHING
WITH THIS FIRST ROUND. NAM/GFS TEMP PROFILES SUGGEST THAT A BAND
OF SIGNIFICANT ICING IS POSSIBLE FROM SE OK UP INTO W CNTRL AR AND
PORTIONS OF NW AR. SOME PLACES HERE MAY PICK UP A QUARTER INCH OR
MORE OF ICE ACCUMULATION...WHICH COULD CAUSE POWER OUTAGES AND
SIGNIFICANT TRAVEL ISSUES. A BAND OF SIGNIFICANT SLEET
ACCUMULATION IS POSSIBLE JUST NORTH OF WHERE THE ZR/IP LINE SETS
UP...MOST LIKELY FROM E CNTRL AND EVENTUALLY PORTIONS OF SE OK
INTO W CNTRL AND NW AR AS THE COLDER AIR GETS DEEPER WITH TIME
FROM NORTH TO SOUTH. THIS COULD CAUSE SIGNIFICANT TRAVEL ISSUES AS
WELL. SOME LIGHT SNOW ACCUMULATION IS MOST LIKELY NEAR THE KANSAS
BORDER. THE FN FORCING SHIFTS SOUTHEAST BY THURSDAY EVENING AND
WEAKENS OVER OUR AREA...ENDING THE FIRST ROUND OF PRECIP.
ROUND TWO BEGINS LATE THURSDAY NIGHT INTO FRIDAY...AS A SHORTWAVE
TROUGH EJECTS EAST FROM THE WESTERN TROUGH OVER THE PLAINS. THE
INCREASING QG FORCING WILL BE MORE BROAD AND WILL COVER MORE OF
THE FORECAST AREA THIS GO AROUND. MODELS SUGGEST THAT A NICE WSW-
ENE ORIENTED DEFORMATION ZONE WILL SET UP FROM SOUTH CENTRAL INTO
NORTHEAST OK AND NORTHWEST AR. LAYER TEMP PROFILES FORECAST BY THE
GFS/ECMWF SUGGEST SNOW OR SNOW/SLEET FOR NE OK AND NW AR...WITH
MORE SLEET ACROSS MUCH OF SE OK AND W CNTRL AR. BASED ON QPF...THIS
COULD LEAD TO SEVERAL INCHES OF SNOW/SLEET ACCUMULATION.
HOWEVER...THE WARM NOSE MAY BE STRONG ENOUGH FOR MORE ZR AND THUS
ICE ACCUMULATION ACROSS FAR SE OK INTO W CNTRL AR LATE THURSDAY
NIGHT AS ROUND TWO GETS GOING. BY FRIDAY MORNING...THE WARM LAYER
IS ERODED ENOUGH FROM THE NORTH TO SHIFT THE BEST ICE POTENTIAL
SOUTH AND EAST OF THE FORECAST AREA. BOTH THE GFS/ECMWF SUGGEST
THAT THE QG FORCING WILL SHUT OFF RAPIDLY BY MIDDAY FRIDAY AS THE
WAVE SHEARS OUT AND LIFTS NORTHEAST OVER THE PLAINS. ROUND TWO
WILL LIKELY BRING MORE TRAVEL HEADACHES ACROSS A LARGER PORTION OF
THE FORECAST AREA. POWER INTERRUPTIONS EITHER MAY DEVELOP OR
CONTINUE OVER AREAS THAT HAVE RECEIVED THE MOST ICE ACCUMULATION
FROM THESE FIRST TWO ROUNDS OF PRECIP.
ROUND THREE GETS GOING OVER THE WEEKEND...AS ANOTHER SHORTWAVE
EMBEDDED WITHIN THE WESTERN CONUS LONGWAVE TROUGH EJECTS NORTHEAST
OVER THE PLAINS...AND A BIT FARTHER NORTH THAN THE PREVIOUS WAVE.
IN ADDITION...WITH THE SURFACE FRONT AND BEST MOISTURE NOW SHUNTED
WELL TO OUR SOUTH AND EAST...THERE WILL NOT BE AS MUCH MOISTURE
FOR THIS SYSTEM TO WORK WITH. INCREASING LOW/MID LVL ISENTROPIC
LIFT WILL RESULT IN AT LEAST LIGHT AMOUNTS OF PRECIPITATION
BEGINNING LATE SATURDAY AND INTO SUNDAY. MODEL SOUNDINGS ARE
FAIRLY DRY OVERALL IN THE CRUCIAL -10 TO -15C LAYER...WITH
MOISTURE MAINLY CONFINED BELOW 700MB. THIS WOULD SUGGEST THAT
PATCHY FREEZING DRIZZLE IS A POSSIBILITY AND HAS THUS BEEN ADDED
TO THE GRIDS. THERE ARE SOME HINTS OF PERIODIC MOISTENING DEEP
ENOUGH FOR ICE PRODUCTION...SO I HAVE ELECTED TO USE MULTIPLE
PRECIP TYPES IN THE GRIDS. THE GFS/ECMWF SUGGEST THAT THE WARM LAYER
WILL EXPAND NORTH INTO OUR AREA SOME DURING THIS TIME...AND THUS
ANOTHER ROUND OF MIXED PRECIP IS POSSIBLE...HOWEVER I WILL
REITERATE THAT PRECIP SHOULD REMAIN LIGHT OVERALL. THIS ROUND OF
PRECIP SHOULD END BY SUNDAY EVENING AS THE WARM CONVEYOR AND
RESULTING ISENTROPIC LIFT SHIFTS EAST OF OUR AREA.
FINALLY...BY EARLY NEXT WEEK THE GFS/ECMWF ARE IN GOOD AGREEMENT
THAT THE PERSISTENT WESTERN LONGWAVE TROUGH WILL LIFT OUT AND SHIFT
EAST OVER THE PLAINS. SOME LIFT AND LIMITED MOISTURE COULD SQUEEZE
OUT SOME LIGHT SNOW ON MONDAY. THIS SHOULD END WINTER PRECIP
CHANCES FOR THE TIME BEING...WHEW.
BOTTOM LINE...AN EXTENDED PERIOD OF VERY COLD WEATHER ALONG WITH
SEVERAL ROUNDS OF WINTRY PRECIPITATION ARE EXPECTED. TRAVEL WILL
BE AFFECTED...AND POWER DELIVERY MAY BE AS WELL IN SOME AREAS.
LOWS ON SATURDAY AND TUESDAY MORNING ARE EXPECTED TO DIP DOWN INTO
THE SINGLE DIGITS WITH WIND CHILLS BELOW ZERO OVER PORTIONS OF THE
AREA. GET READY FOLKS.
THE WINTER STORM WATCH WILL BE CONTINUED FOR THE ENTIRE FORECAST
AREA...WITH WARNINGS LIKELY TO FOLLOW EITHER TONIGHT OR WEDNESDAY.
LACY
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 44 49 28 28 / 0 0 20 70
FSM 48 66 37 37 / 0 0 20 90
MLC 46 59 33 33 / 0 0 20 90
BVO 40 45 26 27 / 0 0 10 60
FYV 47 60 31 31 / 0 0 20 90
BYV 49 62 30 30 / 0 0 20 90
MKO 45 56 31 31 / 0 0 20 90
MIO 45 50 26 27 / 0 0 10 90
F10 44 53 29 30 / 0 0 20 80
HHW 47 70 39 39 / 0 0 20 90
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WINTER STORM WATCH FROM 6 AM THURSDAY TO 6 PM FRIDAY FOR OKZ054-
OKZ055-OKZ056-OKZ057-OKZ058-OKZ059-OKZ060-OKZ061-OKZ062-
OKZ063-OKZ064-OKZ065-OKZ066-OKZ067-OKZ068-OKZ069-OKZ070-
OKZ071-OKZ072-OKZ073-OKZ074-OKZ075.
WINTER STORM WATCH FROM NOON THURSDAY TO 6 PM FRIDAY FOR OKZ049-
OKZ053-OKZ076.
AR...WINTER STORM WATCH FROM 6 AM THURSDAY TO 6 PM FRIDAY FOR ARZ001-
ARZ002-ARZ010-ARZ011-ARZ019.
WINTER STORM WATCH FROM NOON THURSDAY TO 6 PM FRIDAY FOR ARZ020-
ARZ029.
&&
$$
LONG TERM....30
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
1108 AM EST TUE DEC 3 2013
.DISCUSSION...CLOUD COVER SLOWLY ERODING ACROSS NE HALF OF THE
REGION AS FLOW MORE SOUTHWESTERLY BUT HANGING IN ALONG THE PLATEAU
AND SE TN AND SW NC WHERE FLOW IS MORE SOUTHEASTERLY AND UPSLOPE.
EXPECT THE CLEARING SKIES TO CONTINUE NE SO HAVE RAISED HIGHS A
COUPLE DEGREES AND ADDED SOME PARTLY CLOUDY WORDING. LATEST RUC MODEL
SHOWS SHORTWAVE ENERGY TO MOVE ACROSS SE TN AND SW NC SO KEEPING
LOW POPS THERE FOR AFTERNOON. LATE AFTERNOON AND EARLY EVENING
STRONGER SHORTWAVE TO MOVE ACROSS ENTIRE FORECAST AREA SO CLOUDS
LIKELY TO INCREASE IN THE NORTHEAST AFTER 21Z. UPDATED FORECAST SENT.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
TD
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1005 AM CST TUE DEC 3 2013
.UPDATE...
WE/VE EXTENDED THE DENSE FOG UNTIL NOON FOR AREAS ALONG AND NORTH
OF A DENTON TO SULPHUR SPRINGS LINE. MANY REPORTING SITES CONTINUE
TO HAVE VISIBILITIES OF 1/4 MILE OR LESS AND THIS SHOULD PERSIST
INTO MIDDAY LIKE IT DID YESTERDAY. SOME LOCATIONS MAY CONTINUE TO
HAVE FOG PROBLEMS INTO EARLY AFTERNOON...AND WE/LL DECIDE AROUND
MIDDAY WHETHER TO EXTEND IT AGAIN. 75
&&
.AVIATION...
A BAND OF CIRRUS MOVED OVER THE METROPLEX SLOWING THE COOLING A
BIT...BUT IT HAS MOVED EAST OF TAF SITES AND FOG IS STARTING TO
FORM AT DFW AS I WRITE THIS. DENSE FOG REMAINS AS CLOSE AS
DENTON...LANCASTER...AND MESQUITE WHICH APPEARS SIMILAR TO
CONDITIONS YESTERDAY MORNING. HRRR CONTINUES TO SHOW FOG REACHING
DFW AND DAL...BUT NOT THE WESTERN/SOUTHERN SITES. 4KM WRF STOPS
FOG JUST EAST OF TAF SITES AND RUC SOUNDINGS SHOW GROUND FOG.
WITH TWO HOURS TO SUNRISE...CONDITIONS ARE RIPE FOR COOLING TO
CONTINUE AND FOG TO FORM...SO WILL KEEP THE IFR FORECASTS FOR DFW
& DAL. LIKE YESTERDAY...FOG LAYER WILL BE FAIRLY THIN AND SHOULD
BURN OFF QUICKLY AFTER SUNRISE. WITH A STRONG SOUTHWESTERLY LOW
LEVEL JET TOMORROW MORNING...NO RESTRICTIONS TO CIG/VSBY ARE
EXPECTED. 84
&&
.PREV DISCUSSION...
/ISSUED 426 AM CST TUE DEC 3 2013/
STILL SOME MILD WEATHER TO ENJOY BEFORE THE ARCTIC BLAST ARRIVES.
DENSE FOG DEVELOPED OVERNIGHT NORTHEAST OF A BOWIE TO DALLAS TO
CANTON LINE. THIS FOG WILL CONTINUE TO CAUSE SOME PROBLEMS
THROUGH MID MORNING. THUS THE DENSE FOG ADVISORY WILL REMAIN IN
EFFECT UNTIL 10 AM. SOME PATCHY FOG WILL OCCUR FARTHER SOUTH FROM
CORSICANA TO HEARNE EASTWARD...AND IF IT BECOMES WIDESPREAD
ENOUGH WILL EXPAND THE DENSE FOG ADVISORY. AFTER THE FOG BURNS
OFF IT WILL BE A NICE LATE FALL DAY ACROSS THE REGION WITH HIGHS
IN THE UPPER 60S NORTHEAST TO AROUND 80 WEST.
ALTHOUGH TIMING DIFFERENCES BETWEEN THE MODELS CONTINUE CONCERNING
THE NEXT COLD FRONT...THEY HAVE COME CLOSER TO AGREEMENT THAN THEY
WERE 24 HOURS AGO. THE GFS REMAINS THE FASTEST WITH THE FRONT BUT
IS SLOWER THAN IT WAS 24 HOURS AGO...BRINGING THE FRONT INTO THE
NORTHWESTERN ZONES LATE WEDNESDAY MORNING. THE GFS THEN SLOWS
THE SOUTHWARD PROGRESS CONSIDERABLY...BRINGING THE FRONT DOWN
TO A PARIS TO EASTLAND LINE BY 00Z THURSDAY...AND TO A CANTON TO
LAMPASAS BY 12Z THURSDAY. THE ECMWF BRINGS THE FRONT ACROSS THE
RED RIVER AROUND 00Z THURSDAY AND THROUGH THE SOUTHEAST BY 12Z
THURSDAY. THE CMC ALSO BRINGS THE FRONT INTO THE NORTHWEST BY 00Z
THURSDAY BUT BY 12Z...IT PLACES THE FRONT NEAR A TYLER TO TEMPLE
LINE. THE NAM BRINGS THE FRONT DOWN TO A PARIS TO DFW TO HAMILTON
LINE BY 00Z THURSDAY AND THEN THROUGH THE SOUTHEAST BY 12Z
THURSDAY.
THE MODELS AGREE THAT THE FRONT WILL NOT REACH THE I-20 CORRIDOR
UNTIL LATE WEDNESDAY AFTERNOON AT THE EARLIEST AND WILL NOT MOVE
THROUGH THE SOUTHEASTERN COUNTIES UNTIL AROUND OR SHORTLY AFTER
DAYBREAK THURSDAY. THUS HAVE WARMED WEDNESDAY/S TEMPERATURES 5 TO
OVER 10 DEGREES AREA WIDE. LIKEWISE HAVE RAISED THURSDAY MORNINGS
LOWS ACROSS ALL BUT THE NORTHWEST BY 5 TO 10 DEGREES.
THE ARCTIC FRONT WILL MOVE THROUGH NORTH TEXAS THURSDAY WITH MUCH
COLDER TEMPERATURES. THE HIGHS WILL LIKELY OCCUR EARLY MORNING
WITH TEMPERATURES STEADY OR SLOWLY FALLING DURING THE DAY. AN
APPROACHING SHORTWAVE AND UPGLIDE OVER THE FRONT WILL RESULT IN
RAIN STARTING THURSDAY AND INCREASING THURSDAY NIGHT. AS
TEMPERATURES FALL BELOW FREEZING ACROSS THE NORTHWEST...THE RAIN
WILL CHANGE TO FREEZING RAIN THURSDAY NIGHT. BY DAYBREAK FRIDAY
THE FREEZING LINE MAY BE DOWN TO NEAR A SULPHUR SPRINGS TO
KILLEEN LINE. HAVE JUST LEFT A MENTION OF RAIN AT WACO AND
KILLEEN FOR NOW...BUT IT WILL BE CLOSE. THE PRECIPITATION SHOULD
COME TO A TEMPORARY END FROM SOUTHWEST TO NORTHEAST FRIDAY
AFTERNOON AS A SHORTWAVE MOVES OFF TO THE EAST.
UNFORTUNATELY...WITH THE TROUGH STILL BACK TO OUR WEST...WE WILL
REMAIN UNDER THE GUN FOR ADDITIONAL SHORTWAVES TO MOVE ACROSS
OVER THE REGION THE WEEKEND BRINGING A CHANCE OF A WINTRY MIX OF
PRECIPITATION. FORTUNATELY PRECIPITATION AMOUNTS SHOULD NOT BE
HEAVY. THE MAIN TROUGH WILL FINALLY MOVE ACROSS THE SOUTHERN
PLAINS SUNDAY NIGHT...BRINGING AN END TO THE PRECIPITATION
CHANCES BUT COOLER THAN NORMAL TEMPERATURES WILL CONTINUE INTO
THE EARLY PART OF NEXT WEEK. 58
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 74 55 77 38 42 / 0 5 10 20 60
WACO, TX 77 57 79 47 52 / 0 5 10 20 50
PARIS, TX 69 52 72 40 44 / 0 5 5 20 70
DENTON, TX 72 50 73 36 39 / 0 5 5 20 60
MCKINNEY, TX 71 51 75 38 41 / 0 5 10 20 60
DALLAS, TX 74 56 77 39 43 / 0 5 10 20 60
TERRELL, TX 71 57 76 41 47 / 0 5 10 20 60
CORSICANA, TX 74 61 77 48 52 / 0 5 10 20 60
TEMPLE, TX 78 57 79 53 56 / 0 5 10 20 50
MINERAL WELLS, TX 77 52 77 36 40 / 0 5 10 20 60
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR TXZ092>095-103>107.
&&
$$
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