Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/31/13
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
936 AM EST SUN DEC 29 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE NORTHEASTWARD ALONG THE EAST COAST
AND ACROSS THE MID ATLANTIC REGION TODAY BEFORE COMBINING WITH
ANOTHER LOW MOVING THROUGH THE GREAT LAKES AS IT MOVES INTO THE GULF
OF MAINE TONIGHT. A COLD FRONT ASSOCIATED WITH THE GREAT LAKES LOW
WILL CROSS THE REGION EARLY MONDAY MORNING. WEAK HIGH PRESSURE MAY
BRIEFLY AFFECT THE AREA LATE MONDAY INTO MONDAY NIGHT BEFORE A
CLIPPER SYSTEM MOVES ACROSS THE NORTHEAST TUESDAY. STRONGER HIGH
PRESSURE WILL BRIEFLY BUILD ACROSS THE NORTHEAST WEDNESDAY BEFORE
ANOTHER STORM SYSTEM MOVES INTO MID ATLANTIC ON THURSDAY INTO
THURSDAY NIGHT. HIGH PRESSURE IS THEN EXPECTED TO BUILD ACROSS THE
REGION BY SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BAGGY LO PRES CURRENTLY EXTENDS FROM THE VA/NC BORDER NEAR
DANVILLE SOUTHWARD INTO NC WEST OF RALEIGH. WESTWARD MODEL SOLNS
LOOK BETTER. QPF VERIFICATION GFS/CAN GGEM BLEND LOOKS THE BEST.
GEOGRAPHICAL EXTENT/TIMING TO THE ECMWF.
BASED ON LATEST WXNET INFO AND FIRST TIME BEEN ABLE TO USE
NJWXNET`S NEW 5 MIN TIME STEP, IT LOOKS AS THOUGH ALL AVAILABLE
SITES WILL BE ABOVE FREEZING BY 10 AM. THUS THE CHANCES FOR ANY
FREEZING RAIN NORTH ARE ENDING VERY QUICKLY WITH PCPN JUST GETTING
TO I78 NOW. LAPS FREEZING LEVEL FAR NORTH IS AROUND 6K, SO WE
REMOVED MENTION OF SNOW AT START. USED LATEST HRRR TIMING TO BRING
HEAVIER RAIN INTO OUR CWA. MODELS HAVE NOT BEEN BUDGING MUCH FROM
THEIR QPF 1.0 TO 1.5 INCH RANGE WHICH WOULD CAUSE POOR DRAINAGE
FLOODING, BUT KEEP MOST CREEKS AND RIVERS WITHIN BANKFUL. SO FAR
SO GOOD WITH WINDS TO OUR S WHERE THE CURRENT 60KT 925MB JET IS
DEPICTED ON THE NAM, THE PCPN INDUCED INVERSION IS WORKING. NO
BIG CHANGES MADE TO TEMPS OR WINDS.
TODAY WILL BE A GOOD DAY, IF YOU ARE A DUCK! LOW PRESSURE OVER THE
SOUTHEASTERN STATES WILL MOVE NEWD DURG THE DAY AND EMERGE OFFSHORE
OFF THE DELMARVA COAST THIS AFTERNOON. IT WILL THEN CONTINUE ITS
NORTHEASTWARD MOVEMENT AND BE LOCATED NEAR LONG ISLAND THIS EVENING
AND THEN PROGRESS TWD THE CANADIAN MARITIMES TONIGHT.
THE RAIN COULD BECOME HEAVY AT TIMES DURG THE AFTN. A GENL 1 TO
1.25 INCHES OF RAIN IS EXPECTED, WITH THE HIGHEST AMTS S. WITH
GOOD WAA AHEAD OF THE LOW, TEMPS SHOULD MAKE IT WELL INTO THE 40S
AND IN SRN AND ERN SECTIONS AOA 50 DEGREES. THE ONLY EXCEPTIONS
ARE NRN AND WRN AREAS WHERE TEMPS AROUND 40 SHOULD DO IT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
THE AFOREMENTIONED LOW WILL BE MOVG PAST THE REGION TONIGHT AND
PRECIP WILL BE ENDING FROM S TO N. PRECIP SHUD LINGER FOR A BIT
EARLY, ESPECIALLY ACRS THE S, BUT WILL COME TO AND END COMPLETELY BY
MID TO LATE EVENING.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
THE DIGGING SHORT WAVE ASSOCIATED WITH THURSDAY`S SYSTEM IS NOW
PASSING SOUTH OF THE ALEUTIAN ISLANDS.
A COLD FRONT ASSOCIATED WITH THE FORMER GREAT LAKES LOW IS FORECAST
TO MOVE ACROSS THE AREA EARLY MONDAY. WE DO NOT ANTICIPATE ANY
PRECIPITATION DURING THE DAY AS THE COLUMN WILL BE DRYING. THE
VORTICITY IMPULSE SLIDING ACROSS THE AREA DURING THE DAY WILL
LIKELY ONLY INCREASE SOME MID LEVEL CLOUD COVER ACROSS THE AREA.
THE MAIN EFFECT OF THE FRONT WILL BE SOME GUSTY WINDS BEHIND IT.
WINDS COULD GUST 20-25 MPH DURING THE DAY ON MONDAY. THE STRONGEST
WIND GUSTS MAY OCCUR FROM THE MID MORNING HOURS INTO THE EARLY
AFTERNOON BEFORE DIMINISHING LATE IN THE DAY. QUIET WEATHER IS
EXPECTED FOR MONDAY NIGHT AS WEAK HIGH PRESSURE BRIEFLY BUILDS
ACROSS THE AREA.
ON TUESDAY, A WEAK CLIPPER SYSTEM IS EXPECTED TO PASS MOSTLY TO OUR
NORTH. THERE IS NOT MUCH MOISTURE FORECAST WITH THE SYSTEM, AND IT
MAY REMAIN JUST FAR ENOUGH TO OUR NORTH NOT TO BRING OUR AREA ANY
SNOW.
ON WEDNESDAY, HIGH PRESSURE MAY BRIEFLY BUILD ACROSS OUR AREA
BEFORE RETREATING BACK NORTHWARD. THIS MAY AFFECT THE AREA LONG
ENOUGH TO LIMIT THE POSSIBILITY OF PRECIPITATION UNTIL WEDNESDAY
NIGHT. MOISTURE AHEAD OF THE INLAND LOW THAT IS FORECAST TO AFFECT
THE AREA ON THURSDAY MAY GET PULLED ACROSS THE NORTHERN PORTIONS
OF OUR AREA AS EARLY AS OVERNIGHT WEDNESDAY WHICH COULD LEAD TO
SOME LIGHT SNOW ACROSS THE AREA WITH THE COLD AIR IN PLACE.
THINGS REMAIN MURKY ON THE FORECAST FOR THURSDAY. BOTH THE GFS AND
ECMWF HAVE WARMED UP WITH THEIR SOLUTIONS ON THURSDAY COMPARED TO
YESTERDAY. BOTH SHOW A LOW PRESSURE SYSTEM DEVELOPING ACROSS THE
PLAINS AND STRENGTHENING ACROSS THE MID MISSISSIPPI VALLEY AS IT
MOVES TOWARD OUR AREA. BOTH INDICATE A WEAKER COASTAL LOW DEVELOPING
DURING THE DAY THURSDAY, BEFORE THEY MERGE OFF THE MID ATLANTIC
COAST AND STRENGTHEN AS THE SYSTEM MOVES NORTHEAST THURSDAY NIGHT.
AS WE MOVE INTO THURSDAY, THE GFS NOW KEEPS THE BEST CHANCE OF
MOISTURE AND PRECIPITATION ACROSS THE NORTHERN HALF OF THE AREA,
WHILE THE ECMWF BRINGS IN THE MOISTURE ACROSS THE ENTIRE AREA. WE
WILL KEEP CHANCE POPS ACROSS THE WHOLE AREA FOR NOW WITH THE
HIGHEST POPS GENERALLY ACROSS THE NORTHERN HALF. WITH THE GUIDANCE
COMING IN WARMER, THIS WILL PUSH A RAIN/SNOW LINE CLOSER TO THE
I-95 CORRIDOR. DEPENDING ON HOW STRONG THE COLD PUSH IS FROM THE
HIGH RETREATING TO OUR NORTH ON WEDNESDAY NIGHT WILL HAVE AN
EFFECT ON WHERE THIS SETS UP.
THE GFS PULLS THE PRECIPITATION OUT OF THE AREA OVERNIGHT
THURSDAY, BUT THE ECMWF KEEPS IT AROUND THROUGH EARLY FRIDAY, SO
WE WILL KEEP A CHANCE OF PRECIPITATION IN THE FORECAST THROUGH
EARLY FRIDAY. FRIDAY INTO SATURDAY SHOULD BE PRECIPITATION FREE AS
HIGH PRESSURE BUILDS ACROSS THE EAST COAST.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDS EARLY WILL DETERIORATE LATER THIS MORNING TO MVFR AND IFR
AS LOW PRESSURE MOVES FROM THE SOUTHEASTERN STATES TO A POSITION OFF
THE DELMARVA AND THEN TO THE CANADIAN MARITIMES TONIGHT. AS THE LOW
MOVES ACRS THE REGION, RAIN WILL DEVELOP AND COULD BE HEAVY AT
TIMES, ESPECIALLY THIS AFTN. CIGS WILL LOWER AND ITS PSBL THERE CUD
BE SOME REDUCED VSBYS AS WELL ESPECIALLY IN PDS OF HVY RAIN. THE
WIND WILL START OFF SW, BECOME MORE SE OR E AS THE LOW GETS CLOSER
AND THEN SWING AROUND TO THE NW AND BECOME A BIT GUSTY AS THE LOW
PULLS AWAY TONIGHT. GUSTS COULD REACH AS HIGH AS 15 TO 20 KTS.
OUTLOOK...
MONDAY...VFR. GUSTY NORTHWEST WINDS AROUND 25 KNOTS.
MONDAY NIGHT THROUGH WEDNESDAY...VFR.
WEDNESDAY NIGHT-THURSDAY...MVFR DEVELOPING WITH IFR CONDITIONS
POSSIBLE WITH SNOW OR MIXED PRECIPITATION.
&&
.MARINE...
THE GALE WARNING AND SCA WILL REMAIN IN EFFECT UNCHANGED. AN AREA
OF LOW PRESSURE, CURRENTLY OVER THE SERN CONUS WILL MOVE NEWD TO A
POSN OFF THE DELMARVA THIS AFTN THEN NR LI THIS EVE AND OFF THE CAN
MARITIMES TONIGHT. RAIN WILL ACCOMPANY THE LOW AND BOTH SEAS AND
WIND WILL INCREASE. WIND COULD GUST AS HIGH AS 35 TO 40 KT AND SEAS
IN THE 6 TO 9 FT RANGE ARE PSBL ON THE OCEAN.
OUTLOOK...
MONDAY...SCA CONDITIONS POSSIBLE.
MONDAY NIGHT THROUGH WEDNESDAY...MOSTLY SUB ADVISORY CONDITIONS...EXCEPT
POSSIBLE ADVISORY LEVEL ON LATE TUESDAY INTO EARLY TUESDAY NIGHT.
THURSDAY...A RETURN TO ADVISORY CONDITIONS POSSIBLE WITH A STORM
STRENGTHENING ACROSS THE AREA.
THURSDAY NIGHT-FRIDAY...GALE FORCE WIND GUSTS POSSIBLE
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS
EVENING FOR ANZ450>455.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 PM EST
MONDAY FOR ANZ430-431.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...GIGI/NIERENBERG
SHORT TERM...NIERENBERG
LONG TERM...ROBERTSON
AVIATION...NIERENBERG/ROBERTSON
MARINE...NIERENBERG/ROBERTSON
AREA FORECAST DISCUSSION
NWS MIAMI FL
843 PM EST MON DEC 30 2013
.UPDATE...
QUASI-STATIONARY BOUNDARY STILL REMAINS DRAPED ACROSS THE EXTREME
SOUTHEASTERN PORTION OF THE FLORIDA PENINSULA WITH ONLY A COUPLE
OF VERY LIGHT SHOWERS SEEN ACROSS THE ATLANTIC WATERS. NORTHEAST
WINDS ARE STILL EXPECTED TO INCREASE OVERNIGHT AND INTO THE
MORNING HOURS AS HIGH PRESSURE BUILDS INTO THE AREA BEHIND THE
FRONT. KEPT A SLIGHT CHANCE POP ACROSS THE ATLANTIC WATERS DUE TO
THE PROXIMITY OF THE FRONT. THE REMAINDER OF THE FORECAST LOOKS
GOOD.
&&
.PREV DISCUSSION... /ISSUED 648 PM EST MON DEC 30 2013/
AVIATION...A CHALLENGING FORECAST FOR THE OVERNIGHT HOURS
CONCERNING CIGS. NE WINDS ABOVE THE SURFACE WILL BE ON THE
INCREASE OVERNIGHT, ESPECIALLY LATE. DRIER AIR WILL BE MOVING IN
GRADUALLY FROM THE NORTH AS WELL. BUT THIS WILL BE CRITICAL IN
DURATION AND HEIGHT OF CIGS OVERNIGHT. LOOKING AT TRENDS OF SREF
PROBABILITIES AS WELL AS HRRR OUTPUT, HAVE GONE WITH A FORECAST
OF MVFR CIGS DEVELOPING AT ALL EAST COAST TERMINALS BY 02Z WITH
GRADUAL IMPROVEMENT FROM NORTH TO SOUTH...IMPROVING AT KPBI BY 06Z
AND NOT UNTIL THE 10-12Z TIME FRAME AT THE MIAMI-DADE TERMINALS.
DID GO MORE OPTIMISTIC COMPARED TO OUR PREVIOUS TAF FORECAST
GIVEN THE TRENDS AS WELL AS THE FACT THAT NOW NONE OF THE
STATISTICAL GUIDANCE SHOWS IFR DEVELOPING. THERE STILL IS A LOW
CHANCE OF IFR THOUGH AND SO WILL BE MONITORING TRENDS THIS
EVENING. THANKS CWSU MIAMI FOR COLLABORATION THIS EVENING!
/GREGORIA
PREV DISCUSSION... /ISSUED 216 PM EST MON DEC 30 2013/
DISCUSSION...
A STATIONARY FRONT CONTINUES TO LINGER JUST NORTH OF THE YUCATAN
PENINSULA THEN NORTHEASTWARD ACROSS THE GULF WATERS INTO SOUTH
FLORIDA AND ADJACENT WATERS. SO FAR THERE ARE ONLY A FEW ISOLATED
SHOWERS NOTED ACROSS THE LOCAL ATLANTIC WATERS. ALTHOUGH SHOWER
ACTIVITY IS CURRENTLY LIMITED...WINDS ACROSS THE REGION ARE
FORECAST TO BE MORE NORTHERLY LATER THIS EVENING AND OVER NIGHT
WITH OVER-RUNNING ALONG BOUNDARY POSSIBLY RESULTING IN ISOLATED
SHOWERS...WITH ISOLATED ACTIVITY INDICATED IN THE FORECAST AND
GUIDANCE ALSO SUGGESTING A CHANCE OF ISOLATED SHOWERS.
A DIFFUSE FRONT ACROSS THE SOUTHEASTERN STATES IS FORECAST TO MOVE
SOUTHWARD AND INTO THE FLORIDA PENINSULA TONIGHT INTO TUESDAY
WHILE REMAINING DIFFUSE WITH THE STATIONARY FRONT ACROSS SOUTH
FLORIDA EXPECTED TO REMAIN IN PLACE. THE COMBINATION OF THE TWO
FRONTS WILL MAINTAIN EXTENSIVE LOW LEVEL MOISTURE ACROSS THE
REGION WITH MOSTLY CLOUDY SKIES PREVAILING ACROSS SOUTH FLORIDA
THROUGH AT LEAST TUESDAY AND ISOLATED SHOWERS POSSIBLE THROUGH
THAT PERIOD.
BY WEDNESDAY THE BOUNDARY MOISTURE ACROSS SOUTH FLORIDA IS
FORECAST TO LIFT SLOWLY NORTHWARD WITH A CHANCE OF SHOWERS
ESPECIALLY IN THE AFTERNOON HOURS. A GRADUAL DRYING TREND IS
POSSIBLE ON THURSDAY BUT COULD BE SHORT LIVED AS ANOTHER COLD
FRONT IS FORECAST TO PASS INTO SOUTH FLORIDA AND ADJACENT WATERS
THURSDAY NIGHT INTO FRIDAY ALTHOUGH IT COULD BE DIFFUSE AS IT
ENTERS THE AREA.
MARINE...
TONIGHT INTO TUESDAY WINDS ARE FORECAST TO BECOME MORE NORTHERLY
TO NORTH NORTHEASTERLY AND BY LATE TUESDAY A PRE-CAUTIONARY
STATEMENT ACROSS PORTIONS OF THE REGIONAL WATERS MAY BE NECESSARY WITH
WINDS FORECAST TO BE IN THE UPPER PORTION OF THE 15 TO 20 KNOT
RANGE. BY EARLY WEDNESDAY GULF STREAM SEAS COULD BE IN THE 4 TO 6
FOOT RANGE WITH SEAS TO NEAR ADVISORY LEVELS POSSIBLE. BY MID-WEEK
WINDS ARE FORECAST TO BECOME MORE EASTERLY WITH GULF AND ATLANTIC
SEAS SLOWLY DIMINISHING. THE CURRENT GUIDANCE ALSO INDICATES
ANOTHER FRONT APPROACHING THE REGION LATE THURSDAY INTO FRIDAY
WITH STRONG NORTHERLY WINDS ACROSS THE REGIONAL WATERS POSSIBLY
BY LATE FRIDAY WITH SEAS ACROSS PORTIONS OF THE GULF AND ATLANTIC
WATERS BUILDING TO ADVISORY LEVELS ON FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 70 77 72 80 / 20 20 20 30
FORT LAUDERDALE 70 75 72 79 / 20 20 20 30
MIAMI 67 78 71 81 / 20 20 20 30
NAPLES 63 76 65 82 / 20 20 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...57/DG
AREA FORECAST DISCUSSION
NWS MIAMI FL
648 PM EST MON DEC 30 2013
.AVIATION...A CHALLENGING FORECAST FOR THE OVERNIGHT HOURS
CONCERNING CIGS. NE WINDS ABOVE THE SURFACE WILL BE ON THE
INCREASE OVERNIGHT, ESPECIALLY LATE. DRIER AIR WILL BE MOVING IN
GRADUALLY FROM THE NORTH AS WELL. BUT THIS WILL BE CRITICAL IN
DURATION AND HEIGHT OF CIGS OVERNIGHT. LOOKING AT TRENDS OF SREF
PROBABILITIES AS WELL AS HRRR OUTPUT, HAVE GONE WITH A FORECAST
OF MVFR CIGS DEVELOPING AT ALL EAST COAST TERMINALS BY 02Z WITH
GRADUAL IMPROVEMENT FROM NORTH TO SOUTH...IMPROVING AT KPBI BY 06Z
AND NOT UNTIL THE 10-12Z TIME FRAME AT THE MIAMI-DADE TERMINALS.
DID GO MORE OPTIMISTIC COMPARED TO OUR PREVIOUS TAF FORECAST
GIVEN THE TRENDS AS WELL AS THE FACT THAT NOW NONE OF THE
STATISTICAL GUIDANCE SHOWS IFR DEVELOPING. THERE STILL IS A LOW
CHANCE OF IFR THOUGH AND SO WILL BE MONITORING TRENDS THIS
EVENING. THANKS CWSU MIAMI FOR COLLABORATION THIS EVENING!
/GREGORIA
&&
.PREV DISCUSSION... /ISSUED 216 PM EST MON DEC 30 2013/
DISCUSSION...
A STATIONARY FRONT CONTINUES TO LINGER JUST NORTH OF THE YUCATAN
PENINSULA THEN NORTHEASTWARD ACROSS THE GULF WATERS INTO SOUTH
FLORIDA AND ADJACENT WATERS. SO FAR THERE ARE ONLY A FEW ISOLATED
SHOWERS NOTED ACROSS THE LOCAL ATLANTIC WATERS. ALTHOUGH SHOWER
ACTIVITY IS CURRENTLY LIMITED...WINDS ACROSS THE REGION ARE
FORECAST TO BE MORE NORTHERLY LATER THIS EVENING AND OVER NIGHT
WITH OVER-RUNNING ALONG BOUNDARY POSSIBLY RESULTING IN ISOLATED
SHOWERS...WITH ISOLATED ACTIVITY INDICATED IN THE FORECAST AND
GUIDANCE ALSO SUGGESTING A CHANCE OF ISOLATED SHOWERS.
A DIFFUSE FRONT ACROSS THE SOUTHEASTERN STATES IS FORECAST TO MOVE
SOUTHWARD AND INTO THE FLORIDA PENINSULA TONIGHT INTO TUESDAY
WHILE REMAINING DIFFUSE WITH THE STATIONARY FRONT ACROSS SOUTH
FLORIDA EXPECTED TO REMAIN IN PLACE. THE COMBINATION OF THE TWO
FRONTS WILL MAINTAIN EXTENSIVE LOW LEVEL MOISTURE ACROSS THE
REGION WITH MOSTLY CLOUDY SKIES PREVAILING ACROSS SOUTH FLORIDA
THROUGH AT LEAST TUESDAY AND ISOLATED SHOWERS POSSIBLE THROUGH
THAT PERIOD.
BY WEDNESDAY THE BOUNDARY MOISTURE ACROSS SOUTH FLORIDA IS
FORECAST TO LIFT SLOWLY NORTHWARD WITH A CHANCE OF SHOWERS
ESPECIALLY IN THE AFTERNOON HOURS. A GRADUAL DRYING TREND IS
POSSIBLE ON THURSDAY BUT COULD BE SHORT LIVED AS ANOTHER COLD
FRONT IS FORECAST TO PASS INTO SOUTH FLORIDA AND ADJACENT WATERS
THURSDAY NIGHT INTO FRIDAY ALTHOUGH IT COULD BE DIFFUSE AS IT
ENTERS THE AREA.
MARINE...
TONIGHT INTO TUESDAY WINDS ARE FORECAST TO BECOME MORE NORTHERLY
TO NORTH NORTHEASTERLY AND BY LATE TUESDAY A PRE-CAUTIONARY
STATEMENT ACROSS PORTIONS OF THE REGIONAL WATERS MAY BE NECESSARY WITH
WINDS FORECAST TO BE IN THE UPPER PORTION OF THE 15 TO 20 KNOT
RANGE. BY EARLY WEDNESDAY GULF STREAM SEAS COULD BE IN THE 4 TO 6
FOOT RANGE WITH SEAS TO NEAR ADVISORY LEVELS POSSIBLE. BY MID-WEEK
WINDS ARE FORECAST TO BECOME MORE EASTERLY WITH GULF AND ATLANTIC
SEAS SLOWLY DIMINISHING. THE CURRENT GUIDANCE ALSO INDICATES
ANOTHER FRONT APPROACHING THE REGION LATE THURSDAY INTO FRIDAY
WITH STRONG NORTHERLY WINDS ACROSS THE REGIONAL WATERS POSSIBLY
BY LATE FRIDAY WITH SEAS ACROSS PORTIONS OF THE GULF AND ATLANTIC
WATERS BUILDING TO ADVISORY LEVELS ON FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 70 77 72 80 / 20 20 20 30
FORT LAUDERDALE 70 75 72 79 / 20 20 20 30
MIAMI 67 78 71 81 / 20 20 20 30
NAPLES 63 76 65 82 / 20 20 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1150 AM CST SUN DEC 29 2013
.DISCUSSION...
946 AM CST
GOING TO BE ONE OF THOSE DAYS...TIME FOR UPDATE #2 ALREADY.
REPORTS OF MULTIPLE ACCIDENTS WITH ICY ROADS IN SE WI AND NOW
COMING IN FROM LASALLE COUNTY...SO HAVE OPTED TO GO WITH AN
ADVISORY FOR FREEZING DRIZZLE. NOT EXPECTED TO BE A LONG DURATION
EVENT AND LIKELY MAINLY TRACE AMOUNTS...BUT GIVEN THE UPSTREAM
REPORTS AND POTENTIAL FOR SIMILAR CONDITIONS FARTHER EAST FELT THE
COURSE OF LEAST REGRET WAS TO QUICKLY GET OUT AN ADVISORY SINCE
THE FZDZ IS A LATE ADDITION TO THE FORECAST. OVER THE SE HALF OF
THE CWA WHERE TEMPERATURES GOT INTO THE 50S YESTERDAY THE PAVEMENT
TEMPERATURES ARE WARMER AND MAY TAKE LONGER FOR PROBLEMS TO
DEVELOP...BUT SINCE WE DONT HAVE ACCESS TO PAVEMENT TEMPS OR
EXPERIENCE FORECASTING THEM HAVE DECIDED TO INCLUDE THEM IN THE
ADVISORY TOO.
GRIDS ALREADY UPDATED...WSW IS OUT...AND ZFP/LFP ARE FORTHCOMING.
IZZI
//PREV DISCUSSION...
911 AM CST
HAVE MADE SOME ADJUSTMENTS TO PRECIP FORECAST FOR TODAY. UPSTREAM
OBS OVER SOUTHERN WISCONSIN INDICATE AT LEAST AREAS OF FREEZING
DRIZZLE HAVE BEEN OCCURRING. THE 12Z SOUNDINGS FROM GRB/DVN BOTH ARE
PRETTY CLASSIC FZDZ SOUNDINGS WITH FAIRLY DEEP SATURATED LOW LEVELS
WITH TOP OF THE SATURATED LAYER WARMER THAN -10C INDICATING A HIGH
PROBABILITY OF NO ICE NUCLEI IN THE CLOUDS...THUS MAKING SNOW
UNLIKELY. IR IMAGERY CONFIRMS THIS WITH CLOUD TOP TEMPS OF THE
STRATUS IN THE NEIGHBORHOOD OF -8 TO -11C ACROSS NORTHERN IL AND
SOUTHERN WISCONSIN. SHEAR WITHIN THE CLOUD LAYER APPEARS SUFFICIENT
TO SUPPORT COLLISION/COALESCENCE AND A DECENT SHOT OF FZDZ THREAT
CONTINUING INTO OUT CWA LATE THIS MORNING INTO THE EARLY AFTERNOON.
AS LOW LEVEL CONTINUE TO COOL THIS AFTERNOON IT APPEARS THAT TEMPS
WITHIN THE CLOUDS COULD COOL TO AROUND -12 TO -13C WHICH COULD BE
ENOUGH TO ALLOW FOR SOME ICE IN THE STRATUS AND AT LEAST THE
POTENTIAL FOR SOME LIGHT SNOW SHOWERS OR FLURRIES. GIVEN THE SHALLOW
DEPTH OF THE MOISTURE EXPECT TODAY`S PRECIP TO LARGELY BE A TRACE
EVENT...SO HAVE LOWERED THE CHANCE FOR MEASURABLE PRECIP INTO THE
LOW/MID CHANCE RANGE. IT IS WORTH NOTING...THAT IT REALLY ONLY TAKE
A TRACE OF FREEZING DRIZZLE TO CAUSE PROBLEMS AND WILL CONTINUE TO
CLOSELY MONITOR CONDITIONS FOR ANY POSSIBLE SHORT DURATION HEADLINE
OR TO HIT THE FZDZ POTENTIAL HARDER IN THE FORECAST.
SIGNIFICANT DRY AIR ADVECTION LATER THIS AFTERNOON SHOULD PUT AN END
TO THE LIGHT PRECIP THREAT BY MID TO LATE AFTERNOON WITH SKIES
EXPECTED TO CLEAR TONIGHT.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* FREEZING DRIZZLE THROUGH EARLY AFTERNOON.
* FLURRIES/VERY LIGHT SNOW MID/LATE AFTERNOON.
* MVFR CIGS THROUGH EARLY MONDAY MORNING.
* POSSIBLE IFR CIGS EARLY THIS AFTERNOON.
* GUSTY NORTHERLY WINDS TURNING NORTHWEST THIS AFTERNOON...THEN
DIMINISHING THIS EVENING. CMS
//DISCUSSION...UPDATED 18Z...
COLD FRONT IS NOW SOUTH OF THE TERMINALS WITH NORTHERLY WINDS
GUSTING INTO THE MID 20 KT RANGE. WIND DIRECTIONS WILL SLOWLY TURN
MORE NORTHWESTERLY THROUGH THE AFTERNOON AND THEN REMAIN NORTHWEST
INTO THIS EVENING. WIND SPEEDS/GUSTS WILL ALSO SLOWLY DECREASE
THROUGH THE MID/LATE AFTERNOON WITH GUSTS COMPLETELY ENDING BY MID
EVENING.
THE SATURATED LOW LEVELS REMAINED TOO WARM FOR SNOW/ICE CRYSTAL
FORMATION THIS MORNING AND THUS AS THE COLDER AIR SPREAD INTO THE
AREA...FREEZING DRIZZLE DEVELOPED. THIS WILL END OVER THE NEXT FEW
HOURS...FROM NORTH TO SOUTH. STILL THE POTENTIAL FOR SOME FLURRIES
OR VERY LIGHT SNOW...BUT NOT EXPECTING ANYTHING SIGNIFICANT OR ANY
ACCUMULATION.
AS DRIER AIR ADVECTS INTO THE AREA THIS AFTERNOON...CIGS SHOULD
CONTINUE TO LIFT INTO AND REMAIN MVFR INTO THIS EVENING AND
CURRENT CIG TRENDS MAY BE A BIT TOO PESSIMISTIC IN THE SHORT TERM.
BACK EDGE OF CLOUD COVER EXTENDS FROM CENTRAL WI BACK INTO EASTERN
IA AND WILL SLOWLY MOVE SOUTHEAST ACROSS THE TERMINALS LATE THIS
EVENING INTO EARLY MONDAY MORNING. CMS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH FOR FREEZING DRIZZLE EARLY THIS AFTERNOON.
* LOW FOR FLURRIES/VERY LIGHT SNOW MID/LATE THIS AFTERNOON.
* HIGH FOR MVFR CIGS THROUGH LATE TONIGHT.
* LOW FOR IFR CIGS EARLY THIS AFTERNOON.
* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THIS AFTERNOON...MEDIUM
FOR THE REST OF THE PERIOD. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...LIGHT SNOW LIKELY IN THE EVENING WITH A PERIOD OF
MVFR AND IFR CONDITIONS.
TUESDAY...CHANCE OF LIGHT SNOW LATE AFTERNOON...SNOW LIKELY TUE
NIGHT. MVFR BECOMING IFR
WEDNESDAY...CHANCE OF SNOW. MVFR.
THURSDAY...CHANCE OF SNOW. MVFR.
FRIDAY...VFR.
SATURDAY...VFR.
TRS
&&
.MARINE...
433 AM CST
A LOW OVER NORTHERN LOWER MI WILL CONTINUE EASTWARD...DRAGGING A
STRONG COLD FRONT DOWN PAST THE SOUTH TIP OF THE LAKE EARLY TO
MID MORNING...WHILE A STRONG HIGH OVER THE NORTHERN AND CENTRAL
PLAINS SPREADS S AND E...AND ACROSS THE MID MS VALLEY ON MON.
FOLLOWING THE PASSAGE OF THE COLD FRONT IS VERY COLD AIR
SPREADING ACROSS THE UPPER MIDWEST...THE WESTERN GREAT LAKES AND
THE MID MS VALLEY. THE COMBINATION OF THE VERY STRONG COLD AIR
ADVECTION AND A STRONG PRESSURE GRADIENT WILL LEAD TO NW TO N
GALES DEVELOPING ACROSS THE N PORTION OF THE LAKE BY
DAWN...SPREADING DOWN TO THE FAR S PORTION BY LATE MORNING.
THE VERY COLD AIR...STRONG WINDS AND HIGH WAVES WILL LEAD TO THE
POTENTIAL FOR MODERATE TO HEAVY FREEZING SPRAY...WITH THE
GREATEST CHANCE FOR HEAVY FREEZING SPRAY TO OCCUR DURING THIS
AFTERNOON AND THIS EVENING AS TEMPERATURES DROP INTO THE TEENS
AND LOWER 20S. THERE IS THE POTENTIAL FOR SOME HEAVY SPRAY TO
LINGER AS WINDS DROP BELOW GALE FORCE DUE TO THE SLOWER DECREASE
IN WAVE HEIGHTS AND THE ADVECTION OF EVEN COLDER AIR WELL BEHIND
THE FRONT.
ANOTHER ARCTIC HIGH BUILDING INTO THE NORTHERN PLAINS TUE WILL
RESULT IN STRONG NW WINDS ON LAKE MI TUE AND TUE NIGHT ALTHOUGH
THIS SYSTEM SHOULD BE ACCOMPANIED BY A LESSER PRESSURE GRADIENT
AND THE AIR MASS WILL NOT BE QUITE AS COLD...SO ANOTHER ROUND
GALES AND FREEZING SPRAY IS NOT ANTICIPATED AT THIS TIME.
FOR THE NEARSHORE WATERS...THE BETTER CHANGE FOR GALES TODAY
WILL BE OVER THE IN WATERS DUE TO THE DIRECT N TO NW FETCH
PREDOMINANTLY OVER ALL WATER...WHILE THE IL NEARSHORE WATERS
SHOULD REMAIN BELOW GALE FORCE DUE TO SLIGHTLY WEAKER FLOW OFF
LAND. THE GREATEST RISK OF HEAVY FREEZING SPRAY WILL BE ON THE IN
NEARSHORE WATERS...THOUGH ON THE IL NEARSHORE WATERS THERE WILL
LIKELY HEAVY FREEZING SPRAY AS ONE NEARS THE 5 NM FROM SHORE
BOUNDARY AS THE LARGEST WAVES ON THE IL WATERS WILL BE FOUND OUT
NEAR THE OPEN WATERS.
WINDS AND WAVES WILL DIMINISH AS THE HIGH SPREADS E MON NIGHT AND
TUE...BUT ANOTHER LOW IS EXPECTED TO DEVELOP OVER THE NORTHERN
PLAINS MON MORNING AND TRACK E ACROSS NORTHERN IL MON
NIGHT...CONTINUING TO THE EASTERN GREAT LAKES TUE MORNING.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FREEZING RAIN ADVISORY...ILZ004-ILZ005-ILZ006-ILZ011-ILZ012-
ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-
ILZ033-ILZ039 UNTIL 2 PM SUNDAY.
WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020-ILZ021-ILZ032...9 PM SUNDAY TO
NOON MONDAY.
IN...FREEZING RAIN ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019
UNTIL 2 PM SUNDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL MIDNIGHT
MONDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
PM SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...9 PM SUNDAY
TO 4 AM MONDAY.
&&
$$
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
National Weather Service Lincoln IL
1123 AM CST Sun Dec 29 2013
.DISCUSSION...
ISSUED 1018 AM CST Sun Dec 29 2013
Cold front has crossed I-70 and should be through the far
southeast CWA in the next hour. Have been having some freezing
drizzle/mist on the backside of the front, especially along and
north of I-74, although some reports have come in from as far
south as I-72. Upstream morning sounding from Davenport IA and
forecast soundings from the RAP model support this with little ice
crystals aloft to suggest snow. Forecast was updated around 8 am
to add the freezing drizzle, and new update sent scaled back the
snow potential and PoP`s, especially for this afternoon. Have
updated the hourly temperature trends, and should see the far
northwest CWA down into the 10-15 range by sunset.
Geelhart
&&
.AVIATION...
ISSUED 1123 AM CST Sun Dec 29 2013
IFR/LIFR conditions continuing from KPIA-KCMI late this morning,
although worst of the conditions now from KBMI southeast. Will
continue to see some patchy freezing drizzle for a couple hours.
This is a very fine drizzle/mist, and is most easily tracked with
surface visibilities below 3SM. Visibility at KPIA has come up to
5SM recently and ceilings should come up above 1000 feet shortly.
Further south, the IFR ceilings will be improving over the next
couple hours, but again will still be just above 1000 feet. RAP
model shows ceilings scattering out generally between 00-03Z
although taking a bit longer at KCMI. Northwest winds expected to
continue gusting to 20-25 knots into early evening until skies
clear.
Geelhart
&&
.PREV DISCUSSION...
ISSUED 330 AM CST Sun Dec 29 2013
Will issue a wind chill advisory for northern 10 counties from 9
pm this evening until 9 am Monday morning for wind chills of 15 to
20 below zero. The wind chill advisory is roughly along and north
of a Rushville to Bloomington line.
SHORT TERM...Today through Tuesday night
Arctic cold front extends from 1005 mb low pressure over northern
lower MI through southeast WI into NW IL (recently passing SE of
Galesburg) and into central MO. Relatively mild temps in the mid
to upper 30s over central and southeast IL with 41F at Robinson.
Area of light rain over far southeast IL (along and southeast of a
Robinson to Flora line) and into KY/TN and southern IN and
associated with isentropic lift ahead of weakening 558 dm 500 mb
low over the red river valley along the OK/Texas border. This
upper level low to continue to weaken/open up as it ejects into
the TN valley today taking its light rain out of IL early this
morning. Main weather story today will be strong arctic cold front
that quickly sweeps SE through central IL through mid morning and
passes SE of the Wabash river late this morning. Expect temps to
drop behind the cold front with brisk/gusty NW winds behind front
as temps fall to 10F at Galesburg by sunset and near 30F by
Lawrenceville in far southeast IL. NAM models remains dry today
but some other high res models like RAP, HRRR and SREF show
patches of light QPF over mainly northern counties from 15Z-22Z
today. Mainly think scattered flurries with a few light snow
showers possible over mainly northern counties today and not
expecting any accumulations.
Clouds decrease tonight and very cold lows in the single digits
below zero over IL river valley where wind chills reach 15 to 20
below zero by late evening until around 9 am Monday morning. Will
issue a wind chill advisory as stated earlier. Clouds to increase
from NW during Monday and quite cold with highs in the teens over
central IL and lower 20s in southeast IL. A northern stream short
wave to bring chance of light snow to northern areas Monday night.
With another one bringing chances of light snow to northern areas
Tue afternoon and over much of area Tue night with some light snow
accumulations possible mainly north of I-74. Temps to stay well
below normal into the middle of the week.
LONG TERM...Wednesday through Sunday
Medium to long range forecast models and ensembles continue to
show a strong upper level trof digging back into the MS river
valley Wednesday night and Thursday...and models trending with a
deepening surface low pressure ejecting from the central plains
into the Ohio river valley by Thursday morning. Accumulating snows
appear more likely now to fall north of this low pressure track
over central IL and increased pops north Wednesday and across area
Wed night, and best chances of snow shifting east of IL during
Thursday. Trended temperatures colder behind this storm system Thu
night and Friday as below normal temps continue. Large upper level
trof shifts east of IL Fri/Sat with temps moderating closer to
normal next weekend.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 9 PM this evening to 9 AM CST Monday
FOR ILZ027>031-036>038-040-041.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
618 AM CST SUN DEC 29 2013
.DISCUSSION...
342 AM CST
WINTER 2013-2014 IS RETURNING THIS MORNING AFTER A BRIEF 36 HOUR
HIATUS AND THIS PRESENTS PLENTY OF FORECAST CHALLENGES THROUGH THE
START TO THE NEW YEAR. IN PARTICULAR...TEMPERATURES...WIND
CHILLS...AND MULTIPLE ACCUMULATING SNOW CHANCES ARE WHAT THE
EMPHASIS OF TIME WAS SPENT ON THIS MORNING.
THE 1006 MB SURFACE LOW ACROSS LOWER MI EARLY THIS MORNING
CONTINUES TO USHER AN ARCTIC FRONT EASTWARD...WHICH ACTUALLY IS
GETTING MORE OF A PUSH BY THE ARCTIC HIGH EVOLVING SOUTHWARD
BEHIND THE FRONT. THIS BOUNDARY WILL CLEAR THE FORECAST AREA BY
LATE MORNING AND OBSERVATIONS ACROSS EASTERN IOWA INDICATE AROUND
A 15 DEGREE DROP IN THREE HOURS WITH THE FRONT. THIS DEGREE OF
COLD AIR ADVECTION WILL LIKELY EASE SOME...BUT NONETHELESS FALLING
TEMPERATURES THROUGH THE DAY WILL OCCUR AS STRONG PRESSURE RISES
AND PRONOUNCED LOW LEVEL THICKNESS FALLS DRIVE THE BOUNDARY
EASTWARD. THE FIRST SINGLE DIGITS SHOULD ARRIVE IN NORTH CENTRAL
IL DURING MID-AFTERNOON OR SO...WITH SUBZERO READINGS LIKELY BY
MID-EVE.
THE LOW-LEVEL LAPSE RATES WILL OBVIOUSLY QUICKLY STEEPEN BEHIND
FROPA AND EARLY MORNING SATELLITE INDICATES A WIDESPREAD AREA OF
1000-1500 FT STRATOCU CIGS THAT LINE UP WELL WITH THE 1000-850MB
COLD AIR ADVECTION BEHIND THE FRONT. AMDAR SOUNDINGS FROM MSP SHOW
THIS SATURATED LAYER TO BE QUITE SHALLOW WHICH RAP...NAM...AND
LOCAL ARW SOUNDINGS INDICATE WILL INDEED BE THE CASE OVER US THROUGH
TODAY. THIS HAS APPARENTLY STILL BEEN ENOUGH TO GENERATE FLURRIES
AND OCCASIONALLY LIGHT SNOW TO OUR WEST AND NORTHWEST AS SEEN ON
OBS AND THROUGH WIDESPREAD LIGHT ECHOES ON THE ARX AND DMX RADARS.
CONDITIONS MAY BECOME MORE FAVORABLE FOR SNOW SHOWERS DURING THE
DAYTIME TODAY...AND WITH A LITTLE HELP FROM THE MID-LEVEL
VORT...WE CONTINUE TO EXPECT AT LEAST SCATTERED LIGHT SNOW
SHOWERS NAMELY ACROSS THE NORTHERN FORECAST AREA. AROUND ONE HALF
INCH THROUGH THE DAY COULD BE SEEN WITH THESE.
THE CENTER OF THE ARCTIC HIGH IS EXPECTED TO DEVELOP INTO NORTHERN
MO TONIGHT...WITH NVA AND A STRENGTHENING SUBSIDENCE INVERSION
LIKELY HELPING TO ERODE MOST CLOUDS OVER THE CWA AS THE COLUMN
CONTINUES TO DRY. THIS HIGH PLACEMENT WILL STILL ALLOW FOR SOME
WIND COMPONENT AND DANGEROUSLY COLD CONDITIONS ARE EXPECTED WITH
THE COMBINATION OF TEMPERATURES AND WIND. A WIND CHILL ADVISORY
HAS BEEN ISSUED FOR TONIGHT INTO MONDAY MORNING FOR MUCH OF THE
OUTLYING IL CWA WITH WIDESPREAD WIND CHILLS OF -20 TO -30
DEVELOPING AND PERSISTING.
GOING FORWARD INTO THE WEEK...A HANDFUL OF FACTORS ARE IN PLACE
TO CREATE WHAT IS LOOKING LIKE AN INCREASINGLY UNSETTLED PATTERN.
THE HEART OF THE HUDSON BAY TROUGH REACHES THREE STANDARDIZED
ANOMALIES BELOW NORMAL WITH REGARD TO ITS 500MB HEIGHT CENTER OF
AROUND 481DM AND CONTINUED CROSS-POLAR FLOW IS ADVERTISED THROUGH
MID-WEEK BASICALLY KEEPING ITS DEPTH ESTABLISHED. THIS IN ITSELF
ALLOWS FOR STRONG AMPLIFICATION OF THE FLOW PATTERN ACROSS CENTRAL
NORTH AMERICA. ALSO...THE JET ORIENTATION IS SUCH THAT MULTIPLE
PERTURBATIONS WILL NOT ONLY MOVE OVER THE MIDWEST/GREAT LAKES BUT
LIKELY DEEPEN AND POTENTIALLY EVEN PIVOT OVER THE AREA GIVEN THE
LOCATION OF THE BAROCLINIC ZONE. AND FINALLY THAT BAROCLINIC ZONE
IS AROUND THE DENDRITIC GROWTH ZONE MAGNITUDE AND FOR A DECENTLY
LARGE DEPTH AT TIMES WITHIN THE ENVELOPE OF FORECAST GUIDANCE.
ALL IN ALL HAVE TRIED TO REFINE DETAIL THE MOST WITH THE FIRST
WAVES ON MONDAY NIGHT AND TUESDAY NIGHT...WHICH GUIDANCE IS IN
FAIRLY GOOD AGREEMENT ABOUT TIME-WISE. DETAIL WISE SOME NOTABLE
DIFFERENCES THAT COULD YIELD TO A SHARP GRADIENT IN SNOW
PLACEMENT...WHICH WITH A TAUNT BAROCLINIC ZONE CAN CERTAINLY
HAPPEN. BOTH WAVES HAVE LIMITED OVERALL FORCING FOR EVEN PROLONGED
MODERATE SNOW...BUT HAVE GOOD POTENTIAL TO HAVE HIGHER THAN NORMAL
SNOW-TO-LIQUID RATIOS. HAVE BOOSTED POPS MONDAY NIGHT WITH AROUND
AN INCH FORECAST PRESENTLY NEAR THE WI BORDER. AGAIN THIS COULD
SHIFT NORTH OR SOUTH...BUT THE OVERALL MAXIMUM MAGNITUDE OF AROUND
1 TO MAYBE 2 INCHES HAS DECENT CONFIDENCE. FOR TUESDAY NIGHT THE
WAVE IS LESS AMPLIFIED BUT APPEARS TO HAVE FRONTOGENESIS ON ITS
SIDE TO PRODUCE A SMALLER SCALE MORE MODERATE SNOW. OBVIOUSLY
PLACEMENT ON THIS IS LOW CONFIDENCE...BUT DO HAVE SOME EARLY
PROJECTED AMOUNTS OF 1-3 INCHES WITH THIS AND IN TIME THE GRADIENT
OF SNOWFALL AMOUNTS LIKELY WILL NEED TO BE TIGHTENED UP. BUT
PLACEMENT WITH THIS IS QUITE LOW CONFIDENCE RIGHT NOW.
NEWS YEARS DAY INTO POSSIBLY THURSDAY IS LOOKING MORE ACTIVE
ACROSS THE MIDDLE OF THE COUNTRY IN MANY OF THE MODEL MEMBERS AS A
MORE ROBUST WAVE DEVELOPS TO THE WEST AND POSSIBLY OVER THE AREA.
ALMOST A COUPLED JET STRUCTURE IS ADVERTISED BY THE EC AND GFS FOR
00Z THU WHEN THE MID-LEVEL WAVE AND SURFACE LOWS ALL ARE
PROJECTED TO COME TO SHAPE IN THE REGION. WITH THE 850MB LOW EVEN
BEING ADVERTISED AS CLOSED...DEEPENING...AND SLOWLY MOVING ON THE
00Z GFS AND EC...THE ELEMENTS OF SNOW DURATION AND INTENSITY LOOK
LIKE THEY MAY BOTH BE REALIZED ACROSS SOMEWHERE IN THE REGION.
RIGHT NOW...MOST DETERMINISTIC MODELS AND THE GEFS DO FAVOR ARE
FORECAST AREA TO SEE AT LEAST SOME OF THIS AND HAVE ADDED SOME
LIKELY POPS ALREADY ON WEDNESDAY NIGHT. WAY TOO EARLY TO GET INTO
SPECIFICS AS SHIFTS WITH THIS ARE INEVITABLE. BUT SOMETHING
CERTAINLY TO KEEP AN EYE ON AS WE NEAR THE NEW YEAR.
FOR TEMPERATURES CONTINUE TO UNDERCUT A MODEL BLEND BY 2-3 DEGREES
GOING FORWARD...MOST PARTICULARLY OVER NORTH CENTRAL ILLINOIS AND
THE FAR NORTHERN CHICAGO METRO WHERE SNOW COVER REMAINS AND WILL
LIKELY ONLY INCREASE. IF SNOW COVER IS REALIZED OVER THE MUCH OF
THE AREA...THEN THE LOW TEMPERATURES ON FRIDAY AND SATURDAY
MORNINGS ARE LIKELY FAR TOO MILD.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* WIND VEERING AND INCREASING SIGNIFICANTLY FROM W TO NNW-N BY
MID MORNING.
* MVFR CIGS OVERSPREAD THE LOCAL AREA DURING THE EARLY MORNING
WITH PERIODS OF IFR CIGS AND FLURRIES MID TO LATE MORNING.
* PERIOD OF VERY LIGHT SNOW LIKELY DURING FIRST PART OF AFTERNOON.
TRS
//DISCUSSION...UPDATED 12Z...
COLD FRONT KNOCKING AT THE DOOR OF THE ORD AND MDW TERMINALS WITH
WINDS JUST SHIFTING TO OUT OF THE W BETWEEN 11Z AND 12Z...WHILE
RFD SHIFTED TO WNW AT 1030Z. THIS WIND SHIFT IS THE COLD FRONT
MOVING IN BUT THE STRONG GUSTY NW-N WINDS WILL LAG BEHIND THE
FROPA BY A COUPLE HOURS AND ARE CURRENTLY SPREADING INTO FAR
SOUTHERN WI AS WELL AS FAR NW IL.
WITH THE COLD FRONT COMES A DECK OF LOWER END MVFR AND HIGHER END
IFR CIGS. INITIALLY NOT MUCH MOISTURE AVAILABLE FOR PRECIP BUT
PROGS DO SHOW INCREASING MID AND UPPER LEVEL MOISTURE MID MORNING
INTO EARLY AFTERNOON. WITH STRONG COLD AIR ADVECTION SPREADING SE
ACROSS THE AREA AS WELL AS ANOTHER MINOR MID LEVEL SHORT WAVE
TROUGH...CURRENTLY OVER THE DAKOTAS AND FAR NW MN...APPROACHING
THE AREA THIS MORNING AND MOVING OVERHEAD BY LATE AFTERNOON
ANTICIPATE MAINLY FLURRIES OR VERY LIGHT SNOW BUT WITH A PERIOD
OF SLIGHTLY HEAVIER LIGHT SNOW ASSOCIATED WITH THE SECOND SHORT
WAVE MIDDAY-EARLY AFTERNOON THOUGH LITTLE ACCUMULATION.
NW WIND TO BE DROPPING LATE AFTERNOON AND THIS EVE WITH AS
LESSENING OF THE GRADIENT AS LOW PRESSURE MOVES FURTHER E TO N OF
LAKE ONTARIO BY 00Z AND A LARGE AREA OF HIGH PRESSURE BUILDING SE
OVER THE PLAINS TODAY MOVES E TO THE UPPER MIDWEST AND MID MS
VALLEY BY 12Z MON.
WITH STRONG SUBSIDENCE AND DRYING OF THE LOW LEVELS LATE TODAY
AND TONIGHT THE MVFR AND IFR STRATOCUMULUS IS EXPECTED TO CLEAR
OUT DURING THE OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN OVERALL TRENDS.
* MODERATE CONFIDENCE IN TIMING OF PERIOD OF IFR CIGS...LIGHT
SNOW...SPEED OF MAX GUSTINESS.
* LOW CONFIDENCE IN TIMING OF LOSS OF CIGS TONIGHT.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...LIGHT SNOW LIKELY IN THE EVENING WITH A PERIOD OF
MVFR AND IFR CONDITIONS.
TUESDAY...CHANCE OF LIGHT SNOW LATE AFTERNOON...SNOW LIKELY TUE
NIGHT. MVFR BECOMING IFR
WEDNESDAY...CHANCE OF SNOW. MVFR.
THURSDAY...CHANCE OF SNOW. MVFR.
FRIDAY...VFR.
SATURDAY...VFR.
TRS
&&
.MARINE...
433 AM CST
A LOW OVER NORTHERN LOWER MI WILL CONTINUE EASTWARD...DRAGGING A
STRONG COLD FRONT DOWN PAST THE SOUTH TIP OF THE LAKE EARLY TO
MID MORNING...WHILE A STRONG HIGH OVER THE NORTHERN AND CENTRAL
PLAINS SPREADS S AND E...AND ACROSS THE MID MS VALLEY ON MON.
FOLLOWING THE PASSAGE OF THE COLD FRONT IS VERY COLD AIR
SPREADING ACROSS THE UPPER MIDWEST...THE WESTERN GREAT LAKES AND
THE MID MS VALLEY. THE COMBINATION OF THE VERY STRONG COLD AIR
ADVECTION AND A STRONG PRESSURE GRADIENT WILL LEAD TO NW TO N
GALES DEVELOPING ACROSS THE N PORTION OF THE LAKE BY
DAWN...SPREADING DOWN TO THE FAR S PORTION BY LATE MORNING.
THE VERY COLD AIR...STRONG WINDS AND HIGH WAVES WILL LEAD TO THE
POTENTIAL FOR MODERATE TO HEAVY FREEZING SPRAY...WITH THE
GREATEST CHANCE FOR HEAVY FREEZING SPRAY TO OCCUR DURING THIS
AFTERNOON AND THIS EVENING AS TEMPERATURES DROP INTO THE TEENS
AND LOWER 20S. THERE IS THE POTENTIAL FOR SOME HEAVY SPRAY TO
LINGER AS WINDS DROP BELOW GALE FORCE DUE TO THE SLOWER DECREASE
IN WAVE HEIGHTS AND THE ADVECTION OF EVEN COLDER AIR WELL BEHIND
THE FRONT.
ANOTHER ARCTIC HIGH BUILDING INTO THE NORTHERN PLAINS TUE WILL
RESULT IN STRONG NW WINDS ON LAKE MI TUE AND TUE NIGHT ALTHOUGH
THIS SYSTEM SHOULD BE ACCOMPANIED BY A LESSER PRESSURE GRADIENT
AND THE AIR MASS WILL NOT BE QUITE AS COLD...SO ANOTHER ROUND
GALES AND FREEZING SPRAY IS NOT ANTICIPATED AT THIS TIME.
FOR THE NEARSHORE WATERS...THE BETTER CHANGE FOR GALES TODAY
WILL BE OVER THE IN WATERS DUE TO THE DIRECT N TO NW FETCH
PREDOMINANTLY OVER ALL WATER...WHILE THE IL NEARSHORE WATERS
SHOULD REMAIN BELOW GALE FORCE DUE TO SLIGHTLY WEAKER FLOW OFF
LAND. THE GREATEST RISK OF HEAVY FREEZING SPRAY WILL BE ON THE IN
NEARSHORE WATERS...THOUGH ON THE IL NEARSHORE WATERS THERE WILL
LIKELY HEAVY FREEZING SPRAY AS ONE NEARS THE 5 NM FROM SHORE
BOUNDARY AS THE LARGEST WAVES ON THE IL WATERS WILL BE FOUND OUT
NEAR THE OPEN WATERS.
WINDS AND WAVES WILL DIMINISH AS THE HIGH SPREADS E MON NIGHT AND
TUE...BUT ANOTHER LOW IS EXPECTED TO DEVELOP OVER THE NORTHERN
PLAINS MON MORNING AND TRACK E ACROSS NORTHERN IL MON
NIGHT...CONTINUING TO THE EASTERN GREAT LAKES TUE MORNING.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020-ILZ021-ILZ032...9 PM SUNDAY TO
NOON MONDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM SUNDAY TO 9 PM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9
AM SUNDAY TO MIDNIGHT MONDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
PM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ261-LMZ362-LMZ364-LMZ366-
LMZ563-LMZ565 UNTIL MIDNIGHT MONDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...9 AM SUNDAY
TO 4 AM MONDAY.
&&
$$
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
National Weather Service Lincoln IL
503 AM CST Sun Dec 29 2013
.DISCUSSION...
ISSUED 330 AM CST Sun Dec 29 2013
Will issue a wind chill advisory for northern 10 counties from 9
pm this evening until 9 am Monday morning for wind chills of 15 to
20 below zero. The wind chill advisory is roughly along and north
of a Rushville to Bloomington line.
SHORT TERM...Today through Tuesday night
Arctic cold front extends from 1005 mb low pressure over northern
lower MI through southeast WI into NW IL (recently passing se of
Galesburg) and into central MO. Relatively mild temps in the mid
to upper 30s over central and southeast IL with 41F at Robinson.
Area of light rain over far southeast IL (along and southeast of a
Robinson to Flora line) and into KY/TN and southern IN and
associated with isentropic lift ahead of weakening 558 dm 500 mb
low over the red river valley along the OK/Texas border. This
upper level low to continue to weaken/open up as it ejects into
the TN valley today taking its light rain out of IL early this
morning. Main weather story today will be strong arctic cold front
that quickly sweeps se through central IL through mid morning and
passes se of the Wabash river late this morning. Expect temps to
drop behind the cold front with brisk/gusty nw winds behind front
as temps fall to 10F at Galesburg by sunset and near 30F by
Lawrenceville in far southeast IL. NAM models remains dry today
but some other high res models like RAP, HRRR and SREF show
patches of light qpf over mainly northern counties from 15Z-22Z
today. Mainly think scattered flurries with a few light snow
showers possible over mainly northern counties today and not
expecting any accumulations.
Clouds decrease tonight and very cold lows in the single digits
below zero over IL river valley where wind chills reach 15 to 20
below zero by late evening until around 9 am Monday morning. Will
issue a wind chill advisory as stated earlier. Clouds to increase
from nw during Monday and quite cold with highs in the teens over
central IL and lower 20s in southeast IL. A northern stream short
wave to bring chance of light snow to northern areas Monday night.
With another one bringing chances of light snow to northern areas
Tue afternoon and over much of area Tue night with some light snow
accumulations possible mainly north of I-74. Temps to stay well
below normal into the middle of the week.
LONG TERM...Wednesday through Sunday
Medium to long range forecast models and ensembles continue to
show a strong upper level trof digging back into the MS river
valley Wednesday night and Thursday...and models trending with a
deepening surface low pressure ejecting from the central plains
into the Ohio river valley by Thursday morning. Accumulating snows
appear more likely now to fall north of this low pressure track
over central IL and increased pops north Wednesday and across area
Wed night, and best chances of snow shifting east of IL during
Thursday. Trended temperatures colder behind this storm system Thu
night and Friday as below normal temps continue. Large upper level
trof shifts east of IL Fri/Sat with temps moderating closer to
normal next weekend.
07
&&
.AVIATION...
ISSUED 503 AM CST Sun Dec 29 2013
Arctic cold front is near Illinois river at 05z. KPIA shows wind
shift to 310 and gusting. Cigs currently MVFR but upstream
observations indicate a fall to IFR shortly after frontal passage
and persisting for 4-5 hours. These conditions will likely spread
southeast through the remainder of the terminals by 14z. WFO DVN
indicates very small ice crystals occurring behind the front that
are not being picked up by ASOS Present Weather Sensor though some
reduction is being measured.
NAM Time heights indicated thinning of boundary layer RH around
00z at KPIA moving east to KCMI by 04z. Am a little skeptical of
clearing given the time of day and the shallow nature of the air
mass. For now will scatter out low clouds and go skc by morning,
but later forecasts may need to go more pessimistic.
Barker
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 9 PM this evening to 9 AM CST Monday
FOR ILZ027>031-036>038-040-041.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
349 AM CST SUN DEC 29 2013
.DISCUSSION...
922 PM CST
GOING FORECAST FOR TONIGHT IS IN GOOD SHAPE. MAIN TWEAK WAS TO
BUMP UP SKY COVER THIS EVENING WITH CIRRUS CONTINUING TO STREAM
NORTHWARD. WINDS REMAIN ELEVATED OUT OF THE SOUTHWEST BUT WITH
PRESSURE FALLS NOT QUITE AS IMPRESSIVE AS LAST NIGHT...MOST
LOCATIONS HAVE SEEN STEADY OR SLOWLY FALLING TEMPERATURES INSTEAD
OF RISING. DO NOT FORESEE NEEDING TO MAKE BIG CHANGES TO THE LOW
TEMPERATURE FORECAST.
POWERFUL COLD FRONT TRAILING FROM LOW PRESSURE OVER WEST CENTRAL
WISCONSIN STILL ON TRACK TO CROSS THE CWA FROM BEFORE DAYBREAK IN
THE NORTHWEST TO MID MORNING IN THE SOUTHEAST. FALLING
TEMPERATURES AND WINDS GUSTING TO OVER 30 MPH WILL PROVIDE A SLAP
OF WINTER REALITY AFTER THE MILD WEATHER TODAY. WIND CHILL VALUES BY
NIGHTFALL TOMORROW AFTERNOON WILL RANGE FROM AROUND 5 TO 10 BELOW IN
THE NORTHWEST TO 10 ABOVE IN THE SOUTHEAST...WITH SINGLE DIGITS IN
DOWNTOWN CHICAGO. A WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR AT
LEAST PARTS OF THE AREA TOMORROW NIGHT.
THE SET-UP FOR LIGHT SNOW BEHIND THE FRONT IS NOT TOO IMPRESSIVE
WITH A SHALLOW MOIST LAYER BENEATH AN INVERSION ON FORECAST
SOUNDINGS. COULD BE A SITUATION WITH SCATTERED SNOW SHOWERS THAT MAY
PUT DOWN ISOLATED DUSTINGS TO PERHAPS UP TO A HALF INCH IN SOME
SPOTS WHILE MOST OF THE REMAINDER OF THE AREA SEES FLURRIES AND
NO ACCUMULATION. DID NOT MAKE ANY CHANGES BUT WILL PASS ON
CONCERNS TO MIDNIGHT SHIFT.
UPDATED ZFP WILL BE SENT SHORTLY.
RC
//PREV DISCUSSION...
258 PM...MULTIPLE FORECAST CONCERNS CONTINUE THROUGH THE PERIOD
WITH VERY COLD AIR SPREADING BACK ACROSS THE AREA SUNDAY...ALONG
WITH A PERIOD OF LIGHT SNOW. THEN VARIOUS WAVES NEXT WEEK...EACH
WITH THE CHANCE OF ACCUMULATING SNOW...AND CONTINUED BELOW NORMAL
TEMPS.
IN THE SHORT TERM...TEMPS HAVE WARMED INTO THE LOWER TO MID 50S
SOUTH OF THE SNOW PACK UNDER SUNNY SKIES THIS AFTERNOON. WHILE
SOUTHWESTERLY WINDS WILL NOT BE AS STRONG THIS EVENING AS THEY
WERE FRIDAY EVENING...ONCE TEMPS QUICKLY DROP BACK INTO THE LOWER
40S AFTER SUNSET...THEY SHOULD THEN ONLY SLOWLY FALL INTO THE 30S
BY LATE EVENING...ALLOWING FOR ONE LAST MILD EVENING.
LOW PRESSURE OVER SOUTHERN MINNESOTA WILL MOVE EAST ACROSS LAKE
MICHIGAN EARLY SUNDAY MORNING...WITH A STRONG TRAILING COLD FRONT
MOVING ACROSS THE CWA BY MID MORNING SUNDAY. POSSIBLE THAT TEMPS
MAY WARM A FEW DEGREES ACROSS THE EASTERN AREAS AHEAD OF THE FRONT
BUT FOR MUCH OF THE AREA...HIGH TEMPS WILL OCCUR AHEAD OF FROPA
WITH FALLING TEMPS FOR THE REMAINDER OF THE DAY. THESE FALLING
TEMPS COMBINED WITH NORTHWEST WINDS 15-25 MPH WILL PUSH WIND
CHILLS DOWN INTO THE SINGLE DIGITS IN THE AFTERNOON AND BELOW ZERO
AFTER SUNSET. LOWS BY MONDAY MORNING WILL LIKELY RANGE FROM -5 TO
-10 OVER THE SNOW PACK AND COMBINED WITH CONTINUED NORTHWEST WINDS
IN THE 10-15 MPH RANGE...WIND CHILLS WILL LIKELY REACH ADVISORY
LEVEL...-20...MID/LATE SUNDAY EVENING ACROSS THE NORTHWEST CWA
WITH ADVISORY LEVEL WIND CHILLS OVER MUCH OF THE NORTHERN HALF TO
NORTHERN TWO THIRDS OF THE CWA OVERNIGHT INTO MONDAY MORNING AND
A WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR THIS TIME PERIOD
WITH LATER FORECASTS.
AS THE COLDER AIR SPREADS IN BEHIND THE COLD FRONT...THE LOW
LEVELS SATURATE FAIRLY QUICKLY AND AS A WEAK UPPER LEVEL WAVE
SPREADS ACROSS THE AREA...EXPECT A PERIOD OF LIGHT SNOW TO DEVELOP
BY MID MORNING...PERHAPS MORE SHOWERY AT TIMES...AND QUICKLY MOVE
EAST ACROSS THE AREA THROUGH MID/LATE AFTERNOON. MODEL QPF AMOUNTS
ARE ONLY A FEW HUNDREDTHS OF AN INCH...SO NOT EXPECTING MUCH
ACCUMULATION...BUT SNOW MAY START SOMEWHAT WETTER IN THE 12:1
RATIO RANGE AND END MUCH DRIER. HAVE MAINTAINED PATCHY BLOWING
SNOW FROM PREVIOUS FORECAST BUT WITH SUCH LITTLE AMOUNTS...MIGHT
END UP BEING MORE LOW DRIFTING THAN BLOWING. CLOUDS LINGER INTO
THE EVENING WITH A CHANCE FLURRIES...ALL ENDING IN THE LATE
EVENING.
THE MODELS REMAIN IN FAIR AGREEMENT WITH ONE CLIPPER SYSTEM MOVING
ACROSS THE REGION MONDAY NIGHT AND A SECOND LATE TUESDAY AFTERNOON
INTO TUESDAY NIGHT. GIVEN THE CONSISTENCY OVER THE PAST FEW DAYS...
HAVE INCLUDED LIKELY POPS ACROSS THE FAR NORTH MONDAY NIGHT AND
THEN LIKELY POPS ALL AREAS TUESDAY NIGHT. THE AIRMASS WILL REMAIN
VERY COLD...BUT WITH CLOUDS/SNOW...ACTUAL HIGHS/LOWS AND TEMP
TRENDS IS RATHER UNCERTAIN. WITH THE INCREASE IN POPS...ALSO
BUMPED UP TEMPS SOME. AND TIMING WILL BE EVERYTHING...SHOULD SNOW
FALL AT NIGHT...LOWS COULD BE WARMER...IF THE SNOW FALLS DURING
THE DAY...HIGHS COULD BE WARMER...WITH COLD AIR PUNCHING BACK INTO
THE AREA AT NIGHT. THIS DECREASE IN CONFIDENCE REGARDING TEMPS
ALSO DECREASES CONFIDENCE IN SNOW/WATER RATIOS. SOME OF THE COBB
OUTPUT WOULD SUGGEST 20:1 TO 25:1 WHICH IS CERTAINLY POSSIBLE BUT
FROM THIS DISTANCE HAVE GONE MORE MIDDLE OF THE ROAD IN THE 15:1
RANGE. COMBINE THIS UNCERTAINTY WITH QPF AMOUNTS...ITS TOO EARLY
FOR SPECIFIC AMOUNTS...BUT CURRENT TRENDS WOULD SUPPORT AN INCH OR
SO NORTH MONDAY NIGHT AND A FEW TO SEVERAL INCHES TUESDAY NIGHT.
A BIT LARGER CLIPPER/STORM SYSTEM COULD POTENTIALLY AFFECT THE
AREA THURSDAY INTO THURSDAY NIGHT. ALL OF THE MODELS HAVE THIS
FEATURE...TO SOME EXTENT BUT HAVE OPTED TO MAINTAIN LOW CHANCE
POPS FOR NOW. BUT SOME ACCUMULATION WOULD BE POSSIBLE WITH THIS
SYSTEM AND WITH THE POTENTIAL FOR A FRESH SNOW PACK ACROSS THE
ENTIRE AREA BY THIS TIME...HAVE CONTINUED WITH LOWER TEMPS
THURSDAY NIGHT INTO FRIDAY. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* WIND SHIFT TO WNW TOWARD DAWN THEN BECOMING NW AND GUSTY BE MID
MORNING.
* MVFR CIGS SPREAD ACROSS LOCAL AREA WITHIN 1-2 HRS FOLLOWING
FROPA...PERIODS OF IFR CIGS FROM MID MORNING TO EARLY AFTERNOON.
* PERIODS OF FLURRIES AND LIGHT SNOW LATE MORNING THROUGH MID
AFTERNOON AND COULD REDUCE VSBY TO MVFR CAT.
* STRONG GUSTY NW WIND MID MORNING INTO EARLY EVE WILL CAUSE
DRIFTING ACROSS RUNWAYS...TAXIWAYS AND RAMPS THOUGH TOTAL
SNOWFALL EXPECTED TO BE ONLY A FEW TENTHS OF AN IN AT MOST.
TRS
//DISCUSSION...UPDATED 06Z...
LATE MODEL OUTPUT ALL HAVE FROPA OCCURRING AT ORD AND MDW RIGHT
AROUND 12Z ALTHOUGH THIS WILL BE MARKED FIRST BY A WSHFT TO OUT
OF THE W-WNW...AND THE A COUPLE HRS LATER VEERING TO NW-NNW
GUSTING 25-30KT AFTER THE 850HPA TROUGH PASSES BY 15Z-16Z AND THE
700HPA LEVEL TROUGH 17Z-19Z. UPSTREAM THERE CURRENTLY IS AN AREA
OF MAINLY MVFR CIGS...WITH AREAS OF IFR...BEHIND THIS SECOND
SHIFT AND BASED ON FORECAST LOW LEVEL RH PROGS SUSPECT THEY WILL
BE ARRIVING LOCALLY WITH THE WIND VEERING OF WINDS 13Z- 15Z.
INITIALLY NOT MUCH MOISTURE AVAILABLE FOR PRECIP BUT PROGS DO
SHOW INCREASING MID AND UPPER LEVEL MOISTURE MID MORNING INTO
EARLY AFTERNOON. WITH STRONG COLD AIR ADVECTION SPREADING SE AND
ACROSS THE AREA AS WELL AS ANOTHER MINOR MID LEVEL SHORT WAVE
TROUGH APPROACHING THE AREA THIS MORNING AND MOVING OVER HEAD BY
LATE AFTERNOON ANTICIPATE MAINLY FLURRIES OR VERY LIGHT SNOW BUT
WITH A PERIOD OF SLIGHTLY HEAVIER LIGHT SNOW ASSOCIATED WITH THE
SECOND SHORT WAVE.
NW WIND TO BE DROPPING LATE AFTERNOON AND THIS EVE WITH AS
LESSENING OF THE GRADIENT AS LOW PRESSURE MOVES FURTHER E TO N OF
LAKE ONTARIO BY 00Z AND A LARGE AREA OF HIGH PRESSURE BUILDING SE
OVER THE PLAINS TODAY THEN MOVES E TO THE UPPER MIDWEST AND MID
MS VALLEY BY 12Z MON.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN OVER ALL TRENDS.
* MEDIUM CONFIDENCE IN TIMING +/- 1HR OF FROPA...SECONDARY WSHFT
AND AND ARRIVAL OF MVFR AND IFR CIGS.
* HIGH CONFIDENCE IN OCCURRENCE OF SNOW FLURRIES OR VERY LIGHT
SNOW...MEDIUM CONFIDENCE SLIGHTLY HEAVIER LIGHT SNOW MIDDAY AND
EARLY AFTERNOON.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...VFR.
MONDAY NIGHT...CHANCE OF -SN AND IFR.
TUESDAY...CHANCE OF MVFR CIGS.
TUESDAY NIGHT...SNOW AND IFR FAIRLY LIKELY.
WEDNESDAY...MVFR CIGS POSSIBLE.
THURSDAY AND FRIDAY...SOME POTENTIAL FOR SNOW AND IFR...BUT LOW
CONFIDENCE.
IZZI
&&
.MARINE...
400 PM CST
LOW PRESSURE OVER THE EASTERN DAKOTAS WILL TRACK EAST ACROSS THE
FAR NORTHERN TIP OF LAKE MICHIGAN TONIGHT AND CONTINUE EAST
TO SOUTHERN QUEBEC SUNDAY NIGHT WHILE DRAGGING A STRONG COLD FRONT
DOWN THE LENGTH OF THE LAKE. AHEAD OF THE FRONT THIS EVENING...A
MODERATE SOUTHWESTERLY GRADIENT WILL KEEP WINDS ARND 15-25KT.
FOLLOWING THE FRONTAL PASSAGE...VERY COLD AIR WILL FILTER IN OVER
THE LAKE OVERNIGHT TONIGHT AS STRONG HIGH PRESSURE BUILDS ACROSS
THE CENTRAL PLAINS. THE COMBINATION OF THE VERY STRONG COLD
ADVECTION AND STRONG PRESSURE GRADIENT WILL LEAD TO NORTHWEST TO
NORTH GALES DEVELOPING...INITIALLY OVER THE NORTHERN PORTIONS OF
THE LAKE DURING THE EARLY MORNING HOURS. GALES WILL QUICKLY SPREAD
DOWN THE REMAINDER OF THE LAKE EARLY SUNDAY MORNING. THE VERY COLD
AIR...STRONG WINDS AND HIGH WAVES WILL LEAD TO THE POTENTIAL FOR
MODERATE TO HEAVY FREEZING SPRAY...WITH THE GREATEST CHANCE FOR
HEAVY FREEZING SPRAY TO OCCUR DURING THE PERIOD OF THE GALE
WARNING...THOUGH SOME HEAVY SPRAY POTENTIAL COULD STILL LINGER AS
WINDS DROP BELOW GALE FORCE DUE TO THE SLOW DECLINE IN WIND
HEIGHTS AND THE ADVECTION OF COLDER AIR WELL BEHIND THE FRONTAL
BOUNDARY. FOR THE NEARSHORE WATERS...THE BETTER CHANGE FOR GALES
WILL BE OVER THE INDIANA WATERS DUE TO THE DIRECT NORTH TO
NORTHWEST FETCH PREDOMINANTLY OVER ALL WATER...WHILE THE ILLINOIS
NEARSHORE WATERS SHOULD REMAIN BELOW GALE FORCE DUE TO SLIGHTLY
WEAKER FLOW OFF LAND. WINDS AND WAVES WILL DIMINISH AS THE HIGH
SPREADS EAST MONDAY NIGHT AND TUESDAY...BUT ANOTHER LOW IS
EXPECTED TO DEVELOP OVER THE NORTHERN PLAINS MONDAY MORNING AND
TRACK EAST ACROSS NORTHERN ILLINOIS MONDAY NIGHT AND THEN CONTINUE
TO THE EASTERN GREAT LAKES TUESDAY MORNING. AS YET ANOTHER ARCTIC
HIGH PRESSURE SYSTEM BUILDS INTO THE NORTHERN PLAINS TUESDAY
NIGHT...STRONG NORTHWEST WINDS WILL DEVELOP AGAIN FOR TUESDAY AND
TUESDAY NIGHT...BUT THIS SYSTEM SHOULD BE ACCOMPANIED BY A WEAKER
PRESSURE GRADIENT AND THE AIRMASS WILL NOT BE QUITE AS COLD...SO
ANOTHER ROUND GALES AND FREEZING SPRAY IS NOT ANTICIPATED AT THIS
TIME.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020-ILZ021-ILZ032...9 PM SUNDAY TO
NOON MONDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM SUNDAY TO 9 PM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9
AM SUNDAY TO MIDNIGHT MONDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
PM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ261-LMZ362-LMZ364-LMZ366-
LMZ563-LMZ565 UNTIL MIDNIGHT MONDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...9 AM SUNDAY
TO 4 AM MONDAY.
&&
$$
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
National Weather Service Lincoln IL
330 AM CST Sun Dec 29 2013
.DISCUSSION...
ISSUED 330 AM CST Sun Dec 29 2013
Will issue a wind chill advisory for northern 10 counties from 9
pm this evening until 9 am Monday morning for wind chills of 15 to
20 below zero. The wind chill advisory is roughly along and north
of a Rushville to Bloomington line.
SHORT TERM...Today through Tuesday night
Arctic cold front extends from 1005 mb low pressure over northern
lower MI through southeast WI into NW IL (recently passing se of
Galesburg) and into central MO. Relatively mild temps in the mid
to upper 30s over central and southeast IL with 41F at Robinson.
Area of light rain over far southeast IL (along and southeast of a
Robinson to Flora line) and into KY/TN and southern IN and
associated with isentropic lift ahead of weakening 558 dm 500 mb
low over the red river valley along the OK/Texas border. This
upper level low to continue to weaken/open up as it ejects into
the TN valley today taking its light rain out of IL early this
morning. Main weather story today will be strong arctic cold front
that quickly sweeps se through central IL through mid morning and
passes se of the Wabash river late this morning. Expect temps to
drop behind the cold front with brisk/gusty nw winds behind front
as temps fall to 10F at Galesburg by sunset and near 30F by
Lawrenceville in far southeast IL. NAM models remains dry today
but some other high res models like RAP, HRRR and SREF show
patches of light qpf over mainly northern counties from 15Z-22Z
today. Mainly think scattered flurries with a few light snow
showers possible over mainly northern counties today and not
expecting any accumulations.
Clouds decrease tonight and very cold lows in the single digits
below zero over IL river valley where wind chills reach 15 to 20
below zero by late evening until around 9 am Monday morning. Will
issue a wind chill advisory as stated earlier. Clouds to increase
from nw during Monday and quite cold with highs in the teens over
central IL and lower 20s in southeast IL. A northern stream short
wave to bring chance of light snow to northern areas Monday night.
With another one bringing chances of light snow to northern areas
Tue afternoon and over much of area Tue night with some light snow
accumulations possible mainly north of I-74. Temps to stay well
below normal into the middle of the week.
LONG TERM...Wednesday through Sunday
Medium to long range forecast models and ensembles continue to
show a strong upper level trof digging back into the MS river
valley Wednesday night and Thursday...and models trending with a
deepening surface low pressure ejecting from the central plains
into the Ohio river valley by Thursday morning. Accumulating snows
appear more likely now to fall north of this low pressure track
over central IL and increased pops north Wednesday and across area
Wed night, and best chances of snow shifting east of IL during
Thursday. Trended temperatures colder behind this storm system Thu
night and Friday as below normal temps continue. Large upper level
trof shifts east of IL Fri/Sat with temps moderating closer to
normal next weekend.
07
&&
.AVIATION...
ISSUED 1149 PM CST Sat Dec 28 2013
A strong cold front is continuing to approach the central Illinois
terminals from the northwest. Until the front gets here, high
level VFR cigs and southwest winds around 10 kts are likely. The
front should move across the area between 11Z and 14Z. Winds are
expected to swing to the northwest and gust to at least 20 kts
behind the front, and low end MVFR cigs will spread across the
area. Added a 2 hour tempo for IFR cigs behind the front at KPIA
and KBMI based on upstream observations and HRRR cloud progs. Little/no
precipitation is anticipated with fropa. Winds will slowly die off
Sunday night. Skies may also begin to scatter our, but have left
MVFR cigs in place for now as the clearing appears too rapid.
Bak
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 9 PM this evening to 9 AM CST Monday
FOR ILZ027>031-036>038-040-041.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
109 AM CST SUN DEC 29 2013
.DISCUSSION...
922 PM CST
GOING FORECAST FOR TONIGHT IS IN GOOD SHAPE. MAIN TWEAK WAS TO
BUMP UP SKY COVER THIS EVENING WITH CIRRUS CONTINUING TO STREAM
NORTHWARD. WINDS REMAIN ELEVATED OUT OF THE SOUTHWEST BUT WITH
PRESSURE FALLS NOT QUITE AS IMPRESSIVE AS LAST NIGHT...MOST
LOCATIONS HAVE SEEN STEADY OR SLOWLY FALLING TEMPERATURES INSTEAD
OF RISING. DO NOT FORESEE NEEDING TO MAKE BIG CHANGES TO THE LOW
TEMPERATURE FORECAST.
POWERFUL COLD FRONT TRAILING FROM LOW PRESSURE OVER WEST CENTRAL
WISCONSIN STILL ON TRACK TO CROSS THE CWA FROM BEFORE DAYBREAK IN
THE NORTHWEST TO MID MORNING IN THE SOUTHEAST. FALLING
TEMPERATURES AND WINDS GUSTING TO OVER 30 MPH WILL PROVIDE A SLAP
OF WINTER REALITY AFTER THE MILD WEATHER TODAY. WIND CHILL VALUES BY
NIGHTFALL TOMORROW AFTERNOON WILL RANGE FROM AROUND 5 TO 10 BELOW IN
THE NORTHWEST TO 10 ABOVE IN THE SOUTHEAST...WITH SINGLE DIGITS IN
DOWNTOWN CHICAGO. A WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR AT
LEAST PARTS OF THE AREA TOMORROW NIGHT.
THE SET-UP FOR LIGHT SNOW BEHIND THE FRONT IS NOT TOO IMPRESSIVE
WITH A SHALLOW MOIST LAYER BENEATH AN INVERSION ON FORECAST
SOUNDINGS. COULD BE A SITUATION WITH SCATTERED SNOW SHOWERS THAT MAY
PUT DOWN ISOLATED DUSTINGS TO PERHAPS UP TO A HALF INCH IN SOME
SPOTS WHILE MOST OF THE REMAINDER OF THE AREA SEES FLURRIES AND
NO ACCUMULATION. DID NOT MAKE ANY CHANGES BUT WILL PASS ON
CONCERNS TO MIDNIGHT SHIFT.
UPDATED ZFP WILL BE SENT SHORTLY.
RC
//PREV DISCUSSION...
258 PM...MULTIPLE FORECAST CONCERNS CONTINUE THROUGH THE PERIOD
WITH VERY COLD AIR SPREADING BACK ACROSS THE AREA SUNDAY...ALONG
WITH A PERIOD OF LIGHT SNOW. THEN VARIOUS WAVES NEXT WEEK...EACH
WITH THE CHANCE OF ACCUMULATING SNOW...AND CONTINUED BELOW NORMAL
TEMPS.
IN THE SHORT TERM...TEMPS HAVE WARMED INTO THE LOWER TO MID 50S
SOUTH OF THE SNOW PACK UNDER SUNNY SKIES THIS AFTERNOON. WHILE
SOUTHWESTERLY WINDS WILL NOT BE AS STRONG THIS EVENING AS THEY
WERE FRIDAY EVENING...ONCE TEMPS QUICKLY DROP BACK INTO THE LOWER
40S AFTER SUNSET...THEY SHOULD THEN ONLY SLOWLY FALL INTO THE 30S
BY LATE EVENING...ALLOWING FOR ONE LAST MILD EVENING.
LOW PRESSURE OVER SOUTHERN MINNESOTA WILL MOVE EAST ACROSS LAKE
MICHIGAN EARLY SUNDAY MORNING...WITH A STRONG TRAILING COLD FRONT
MOVING ACROSS THE CWA BY MID MORNING SUNDAY. POSSIBLE THAT TEMPS
MAY WARM A FEW DEGREES ACROSS THE EASTERN AREAS AHEAD OF THE FRONT
BUT FOR MUCH OF THE AREA...HIGH TEMPS WILL OCCUR AHEAD OF FROPA
WITH FALLING TEMPS FOR THE REMAINDER OF THE DAY. THESE FALLING
TEMPS COMBINED WITH NORTHWEST WINDS 15-25 MPH WILL PUSH WIND
CHILLS DOWN INTO THE SINGLE DIGITS IN THE AFTERNOON AND BELOW ZERO
AFTER SUNSET. LOWS BY MONDAY MORNING WILL LIKELY RANGE FROM -5 TO
-10 OVER THE SNOW PACK AND COMBINED WITH CONTINUED NORTHWEST WINDS
IN THE 10-15 MPH RANGE...WIND CHILLS WILL LIKELY REACH ADVISORY
LEVEL...-20...MID/LATE SUNDAY EVENING ACROSS THE NORTHWEST CWA
WITH ADVISORY LEVEL WIND CHILLS OVER MUCH OF THE NORTHERN HALF TO
NORTHERN TWO THIRDS OF THE CWA OVERNIGHT INTO MONDAY MORNING AND
A WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR THIS TIME PERIOD
WITH LATER FORECASTS.
AS THE COLDER AIR SPREADS IN BEHIND THE COLD FRONT...THE LOW
LEVELS SATURATE FAIRLY QUICKLY AND AS A WEAK UPPER LEVEL WAVE
SPREADS ACROSS THE AREA...EXPECT A PERIOD OF LIGHT SNOW TO DEVELOP
BY MID MORNING...PERHAPS MORE SHOWERY AT TIMES...AND QUICKLY MOVE
EAST ACROSS THE AREA THROUGH MID/LATE AFTERNOON. MODEL QPF AMOUNTS
ARE ONLY A FEW HUNDREDTHS OF AN INCH...SO NOT EXPECTING MUCH
ACCUMULATION...BUT SNOW MAY START SOMEWHAT WETTER IN THE 12:1
RATIO RANGE AND END MUCH DRIER. HAVE MAINTAINED PATCHY BLOWING
SNOW FROM PREVIOUS FORECAST BUT WITH SUCH LITTLE AMOUNTS...MIGHT
END UP BEING MORE LOW DRIFTING THAN BLOWING. CLOUDS LINGER INTO
THE EVENING WITH A CHANCE FLURRIES...ALL ENDING IN THE LATE
EVENING.
THE MODELS REMAIN IN FAIR AGREEMENT WITH ONE CLIPPER SYSTEM MOVING
ACROSS THE REGION MONDAY NIGHT AND A SECOND LATE TUESDAY AFTERNOON
INTO TUESDAY NIGHT. GIVEN THE CONSISTENCY OVER THE PAST FEW DAYS...
HAVE INCLUDED LIKELY POPS ACROSS THE FAR NORTH MONDAY NIGHT AND
THEN LIKELY POPS ALL AREAS TUESDAY NIGHT. THE AIRMASS WILL REMAIN
VERY COLD...BUT WITH CLOUDS/SNOW...ACTUAL HIGHS/LOWS AND TEMP
TRENDS IS RATHER UNCERTAIN. WITH THE INCREASE IN POPS...ALSO
BUMPED UP TEMPS SOME. AND TIMING WILL BE EVERYTHING...SHOULD SNOW
FALL AT NIGHT...LOWS COULD BE WARMER...IF THE SNOW FALLS DURING
THE DAY...HIGHS COULD BE WARMER...WITH COLD AIR PUNCHING BACK INTO
THE AREA AT NIGHT. THIS DECREASE IN CONFIDENCE REGARDING TEMPS
ALSO DECREASES CONFIDENCE IN SNOW/WATER RATIOS. SOME OF THE COBB
OUTPUT WOULD SUGGEST 20:1 TO 25:1 WHICH IS CERTAINLY POSSIBLE BUT
FROM THIS DISTANCE HAVE GONE MORE MIDDLE OF THE ROAD IN THE 15:1
RANGE. COMBINE THIS UNCERTAINTY WITH QPF AMOUNTS...ITS TOO EARLY
FOR SPECIFIC AMOUNTS...BUT CURRENT TRENDS WOULD SUPPORT AN INCH OR
SO NORTH MONDAY NIGHT AND A FEW TO SEVERAL INCHES TUESDAY NIGHT.
A BIT LARGER CLIPPER/STORM SYSTEM COULD POTENTIALLY AFFECT THE
AREA THURSDAY INTO THURSDAY NIGHT. ALL OF THE MODELS HAVE THIS
FEATURE...TO SOME EXTENT BUT HAVE OPTED TO MAINTAIN LOW CHANCE
POPS FOR NOW. BUT SOME ACCUMULATION WOULD BE POSSIBLE WITH THIS
SYSTEM AND WITH THE POTENTIAL FOR A FRESH SNOW PACK ACROSS THE
ENTIRE AREA BY THIS TIME...HAVE CONTINUED WITH LOWER TEMPS
THURSDAY NIGHT INTO FRIDAY. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* WIND SHIFT TO WNW TOWARD DAWN THEN BECOMING NW AND GUSTY BE MID
MORNING.
* MVFR CIGS SPREAD ACROSS LOCAL AREA WITHIN 1-2 HRS FOLLOWING
FROPA...PERIODS OF IFR CIGS FROM MID MORNING TO EARLY AFTERNOON.
* PERIODS OF FLURRIES AND LIGHT SNOW LATE MORNING THROUGH MID
AFTERNOON AND COULD REDUCE VSBY TO MVFR CAT.
* STRONG GUSTY NW WIND MID MORNING INTO EARLY EVE WILL CAUSE
DRIFTING ACROSS RUNWAYS...TAXIWAYS AND RAMPS THOUGH TOTAL
SNOWFALL EXPECTED TO BE ONLY A FEW TENTHS OF AN IN AT MOST.
TRS
//DISCUSSION...UPDATED 06Z...
LATE MODEL OUTPUT ALL HAVE FROPA OCCURRING AT ORD AND MDW RIGHT
AROUND 12Z ALTHOUGH THIS WILL BE MARKED FIRST BY A WSHFT TO OUT
OF THE W-WNW...AND THE A COUPLE HRS LATER VEERING TO NW-NNW
GUSTING 25-30KT AFTER THE 850HPA TROUGH PASSES BY 15Z-16Z AND THE
700HPA LEVEL TROUGH 17Z-19Z. UPSTREAM THERE CURRENTLY IS AN AREA
OF MAINLY MVFR CIGS...WITH AREAS OF IFR...BEHIND THIS SECOND
SHIFT AND BASED ON FORECAST LOW LEVEL RH PROGS SUSPECT THEY WILL
BE ARRIVING LOCALLY WITH THE WIND VEERING OF WINDS 13Z- 15Z.
INITIALLY NOT MUCH MOISTURE AVAILABLE FOR PRECIP BUT PROGS DO
SHOW INCREASING MID AND UPPER LEVEL MOISTURE MID MORNING INTO
EARLY AFTERNOON. WITH STRONG COLD AIR ADVECTION SPREADING SE AND
ACROSS THE AREA AS WELL AS ANOTHER MINOR MID LEVEL SHORT WAVE
TROUGH APPROACHING THE AREA THIS MORNING AND MOVING OVER HEAD BY
LATE AFTERNOON ANTICIPATE MAINLY FLURRIES OR VERY LIGHT SNOW BUT
WITH A PERIOD OF SLIGHTLY HEAVIER LIGHT SNOW ASSOCIATED WITH THE
SECOND SHORT WAVE.
NW WIND TO BE DROPPING LATE AFTERNOON AND THIS EVE WITH AS
LESSENING OF THE GRADIENT AS LOW PRESSURE MOVES FURTHER E TO N OF
LAKE ONTARIO BY 00Z AND A LARGE AREA OF HIGH PRESSURE BUILDING SE
OVER THE PLAINS TODAY THEN MOVES E TO THE UPPER MIDWEST AND MID
MS VALLEY BY 12Z MON.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN OVER ALL TRENDS.
* MEDIUM CONFIDENCE IN TIMING +/- 1HR OF FROPA...SECONDARY WSHFT
AND AND ARRIVAL OF MVFR AND IFR CIGS.
* HIGH CONFIDENCE IN OCCURRENCE OF SNOW FLURRIES OR VERY LIGHT
SNOW...MEDIUM CONFIDENCE SLIGHTLY HEAVIER LIGHT MIDDAY-EARLY
AFTERNOON.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...VFR.
MONDAY NIGHT...CHANCE OF -SN AND IFR.
TUESDAY...CHANCE OF MVFR CIGS.
TUESDAY NIGHT...SNOW AND IFR FAIRLY LIKELY.
WEDNESDAY...MVFR CIGS POSSIBLE.
THURSDAY AND FRIDAY...SOME POTENTIAL FOR SNOW AND IFR...BUT LOW
CONFIDENCE.
IZZI
&&
.MARINE...
400 PM CST
LOW PRESSURE OVER THE EASTERN DAKOTAS WILL TRACK EAST ACROSS THE
FAR NORTHERN TIP OF LAKE MICHIGAN TONIGHT AND CONTINUE EAST
TO SOUTHERN QUEBEC SUNDAY NIGHT WHILE DRAGGING A STRONG COLD FRONT
DOWN THE LENGTH OF THE LAKE. AHEAD OF THE FRONT THIS EVENING...A
MODERATE SOUTHWESTERLY GRADIENT WILL KEEP WINDS ARND 15-25KT.
FOLLOWING THE FRONTAL PASSAGE...VERY COLD AIR WILL FILTER IN OVER
THE LAKE OVERNIGHT TONIGHT AS STRONG HIGH PRESSURE BUILDS ACROSS
THE CENTRAL PLAINS. THE COMBINATION OF THE VERY STRONG COLD
ADVECTION AND STRONG PRESSURE GRADIENT WILL LEAD TO NORTHWEST TO
NORTH GALES DEVELOPING...INITIALLY OVER THE NORTHERN PORTIONS OF
THE LAKE DURING THE EARLY MORNING HOURS. GALES WILL QUICKLY SPREAD
DOWN THE REMAINDER OF THE LAKE EARLY SUNDAY MORNING. THE VERY COLD
AIR...STRONG WINDS AND HIGH WAVES WILL LEAD TO THE POTENTIAL FOR
MODERATE TO HEAVY FREEZING SPRAY...WITH THE GREATEST CHANCE FOR
HEAVY FREEZING SPRAY TO OCCUR DURING THE PERIOD OF THE GALE
WARNING...THOUGH SOME HEAVY SPRAY POTENTIAL COULD STILL LINGER AS
WINDS DROP BELOW GALE FORCE DUE TO THE SLOW DECLINE IN WIND
HEIGHTS AND THE ADVECTION OF COLDER AIR WELL BEHIND THE FRONTAL
BOUNDARY. FOR THE NEARSHORE WATERS...THE BETTER CHANGE FOR GALES
WILL BE OVER THE INDIANA WATERS DUE TO THE DIRECT NORTH TO
NORTHWEST FETCH PREDOMINANTLY OVER ALL WATER...WHILE THE ILLINOIS
NEARSHORE WATERS SHOULD REMAIN BELOW GALE FORCE DUE TO SLIGHTLY
WEAKER FLOW OFF LAND. WINDS AND WAVES WILL DIMINISH AS THE HIGH
SPREADS EAST MONDAY NIGHT AND TUESDAY...BUT ANOTHER LOW IS
EXPECTED TO DEVELOP OVER THE NORTHERN PLAINS MONDAY MORNING AND
TRACK EAST ACROSS NORTHERN ILLINOIS MONDAY NIGHT AND THEN CONTINUE
TO THE EASTERN GREAT LAKES TUESDAY MORNING. AS YET ANOTHER ARCTIC
HIGH PRESSURE SYSTEM BUILDS INTO THE NORTHERN PLAINS TUESDAY
NIGHT...STRONG NORTHWEST WINDS WILL DEVELOP AGAIN FOR TUESDAY AND
TUESDAY NIGHT...BUT THIS SYSTEM SHOULD BE ACCOMPANIED BY A WEAKER
PRESSURE GRADIENT AND THE AIRMASS WILL NOT BE QUITE AS COLD...SO
ANOTHER ROUND GALES AND FREEZING SPRAY IS NOT ANTICIPATED AT THIS
TIME.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 9 AM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9
AM SUNDAY TO MIDNIGHT MONDAY.
GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM SUNDAY TO 9 PM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ261-LMZ362-LMZ364-LMZ366-
LMZ563-LMZ565...4 AM SUNDAY TO MIDNIGHT MONDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 AM
SUNDAY TO 6 PM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 4 AM
MONDAY.
&&
$$
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
National Weather Service Lincoln IL
1149 PM CST Sat Dec 28 2013
.DISCUSSION...
ISSUED 859 PM CST Sat Dec 28 2013
Made a few minor adjustments to the afternoon forecast package.
The first was to bump up cloud cover for the rest of the night.
The southern stream wave heading toward the Ohio Valley from the
southern Plains has been spilling more cloud cover back toward the
area than previously expected per recent satellite loops. See no
reason why this trend will not continue through the night. Also,
increased the speed of the approaching arctic front just a bit per
recent observational trends and short range rapid update model
progs. Otherwise, only a few tweaks were needed to the hourly
trends.
Bak
&&
.AVIATION...
ISSUED 1149 PM CST Sat Dec 28 2013
A strong cold front is continuing to approach the central Illinois
terminals from the northwest. Until the front gets here, high
level VFR cigs and southwest winds around 10 kts are likely. The
front should move across the area between 11Z and 14Z. Winds are
expected to swing to the northwest and gust to at least 20 kts
behind the front, and low end MVFR cigs will spread across the
area. Added a 2 hour tempo for IFR cigs behind the front at KPIA
and KBMI based on upstream observations and HRRR cloud progs. Little/no
precipitation is anticipated with fropa. Winds will slowly die off
Sunday night. Skies may also begin to scatter our, but have left
MVFR cigs in place for now as the clearing appears too rapid.
Bak
&&
.PREV DISCUSSION...
ISSUED 215 PM CST Sat Dec 28 2013
Another unseasonably warm afternoon across central through southeast
Illinois thanks to abundant sunshine and a gusty southwest wind.
Early afternoon temperatures have already climbed into the lower
40s northwest to the lower 50s west and south. An Arctic cold
front was located over far southeast South Dakota through central
Nebraska with strong 3 hourly pressure rises noted behind the
boundary. Temps just ahead of the front were in the mid 40s to mid
50s while only in the single digits behind the front in extreme
northern South Dakota.
SHORT TERM...Tonight through Tuesday
Bone chilling cold headed towards our area late Sunday and Monday
with wind chill readings dropping to around 20 below zero across
the north by Monday morning.
Temps/Wind chills the main forecast concerns this period along
with light snow chances as fast moving shortwaves ride southeast
along the Arctic air mass about every other day.
No major differences seen in the models through Monday, at least
with the handling of the strong cold front late tonight into
Sunday morning. The Arctic boundary is forecast to streak southeast
tonight and push across our area Sunday morning. Southwest winds
ahead of the front will keep temperatures relatively mild tonight,
at least in comparison to what we will be seeing early in the
week. On Sunday, most areas should see morning high temperatures
with falling temps expected in the afternoon.
As far as precip is concerned on Sunday, the southern stream system,
currently pushing across Texas and spreading clouds as far north
as our southeast counties, may bring a period of light rain and snow
to the southeast tomorrow morning into the afternoon hours before
the temp profile supports more light snow. Meanwhile, further north,
as the Arctic air mass settles southeast into our area and a 500
mb shortwave approaches from the northwest in the afternoon, there
may be enough moisture in place to support scattered snow showers
from time to time. The NAM-WRF Bufkit sounding profiles suggest
the threat for a brief period of light drizzle or possibly freezing
drizzle before the depth of the cold air increases enough Sunday
morning to support mainly flurries. For now, will not mention in
the forecast as the window of opportunity for any drizzle/freezing
drizzle looks too brief to include in the forecast. Precip amounts
look very light and will continue with the 20 to 30 POPs.
Any lingering snow showers or flurries should be to our east by
tomorrow evening as the Arctic air mass becomes firmly entrenched
across the forecast area overnight. Forecast soundings for Sunday
night into Monday continues to indicate winds to hold up most of
the night as the very cold air mass settles in, creating dangerously
cold wind chills, generally ranging from -10 to -20 northwest, and
from 0 to -10 over the remainder of the area Monday morning. Wind
chills will only gradually improve during the day on Monday as
winds slowly decrease as the center of the cold air mass tracks
over our area by evening. Clouds will be on the increase during
the day, especially across the north as a fast moving shortwave
approaches the lower Great Lakes from the northwest by evening.
It still appears the better forcing and moisture will remain to
our north Monday night into early Tuesday but will continue to
hold on to low chance POPs over our northern counties before the
system pushes off to our east Tuesday. A stronger shortwave will
follow the Monday night system for later Tuesday and Tuesday night
spreading the threat for light snow further south. Both the GFS
and latest ECMWF showing better deep layered forcing and moisture
associated with this feature, so POPs will be increased further
south late Tuesday into Tuesday night. With the snow ratio`s on
the order of 20:1, parts of our northern counties may see some light
accumulations Tuesday night.
LONG TERM...Wednesday through Saturday
Little change expected in the longwave pattern through most of this
forecast period as the cold vortex anchored north of the Great Lakes
will continue to bring us below normal temps thru this period. Some
of the ensemble members suggest at least a temporary break in the
very cold pattern late in the period as the Canadian vortex shifts
off to the east, while another upper low rotates south over central
Canada, probably to set up shop near Hudson Bay again beyond this
forecast period.
Another fast moving shortwave embedded in the northwest flow will
track southeast across the Plains on Wednesday inducing a surface
wave across the southern Plains, which models were suggesting would
move northeast across southern Illinois into Indiana on Thursday,
followed by another shot of Arctic air for the end of the week.
Before the Arctic air moves in, both the latest ECMWF and GEM
global indicates some fairly significant lift associated ahead of
the H5 trof later Wednesday into early Thursday as the upper wave
digs into the longwave trof position, which may bring another
threat for snow to the area. The 00z Canadian had depicted this
scenario first on its 00z run last evening, now the 12z ECMWF is
latching on to the snowier look to the Wed night into Thursday.
Both models indicate a closed 850 mb low across central Illinois
late Wednesday night or Thursday which would enhance snowfall over
the area. Latest SREF not as aggressive with the system while the
12z GFS indicates the better lift will track mostly south of area.
So until we get some continuity with models for the mid-week system,
will keep the POPs in the chance category for now.
As mentioned above, models are trending towards a warmer pattern,
at least a temporary one, at the end of this forecast period as the
polar vortex migrates off into eastern Canada. Meanwhile, our
upper flow begins to back in response to a trof pushing into the
Rockies late next weekend, resulting in warmer temperatures for
Saturday with highs in the 30s.
Smith
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1123 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 840 AM CST SUN DEC 29 2013
A QUICK UPDATE SENT TO SLIGHTLY CHANGE THE OUTLINE OF WIND CHILL
ADVISORY COUNTIES IN WEST CENTRAL ILLINOIS. WE HAVE ADDED THE
COUNTIES OF DES MOINES...HENDERSON...WARREN...AND MCDONOUGH. WHILE
CRITERIA IS MARGINAL FOR WIND CHILLS...THE COLLABORATION WITH
SURROUNDING OFFICES WILL CONVEY A MUCH MORE CONSISTENT MESSAGE
WITH THE INCLUSION OF THESE COUNTIES.
ERVIN
UPDATE ISSUED AT 726 AM CST SUN DEC 29 2013
BASED ON RADAR DUAL POL DATA IN CONCERT WITH WEAK VISIBILITY
RESTRICTIONS FROM THE LIGHT PRECIPITATION...HAVE ADDED PATCHY
FREEZING DRIZZLE THROUGH MID MORNING TO THE FORECAST.
IF THE TRENDS IN THE RAP ARE CORRECT...THE CURRENT FORCING MOVING
THROUGH THE AREA WITH DRIER AIR ALOFT IS PRODUCING SOME LIGHT SNOW
MIXED WITH VERY LIGHT FREEZING DRIZZLE. THIS SHALLOW MOISTURE
SHOULD EXIT THE AREA SHORTLY AFTER MID MORNING.
ACROSS CENTRAL IOWA...THERE IS ANOTHER AREA OF FORCING BUT THE
MOISTURE IS A BIT DEEPER BASED ON CONDENSATION PRESSURE DEFICITS.
HERE PRECIPITATION IS STILL LIGHT BUT OBSERVATIONS AND RADAR DATA
SUGGEST MORE FLURRIES OR VERY LIGHT SNOW INSTEAD OF FREEZING DRIZZLE.
REGARDING THE CURRENT HEADLINES...THE COLDER AIR IS NOT MOVING IN
AS FAST AS THE SHORT RANGE MODEL TRENDS HAVE BEEN SUGGESTING. THIS
OBSERVATIONAL TREND BRINGS QUESTIONS AS TO WHETHER OR NOT 15 BELOW
ZERO IS ACHIEVABLE TONIGHT IN AREAS WEST OF A DUBUQUE TO IOWA CITY
LINE. IF THIS IS THE CASE...THEN WIND CHILLS WOULD NOT PROBABLY
NOT EXCEED 30 BELOW ZERO EITHER. THIS AREA IS RIGHT ON THE CUSP
BETWEEN AN ADVISORY AND A WARNING FOR WIND CHILL. TRENDS THROUGH
THE DAY WILL BE CRITICAL IN DETERMINING WHICH WAY THE HEADLINE
WILL EVENTUALLY GO FOR TONIGHT.
UPDATE ISSUED AT 532 AM CST SUN DEC 29 2013
TEMPERATURES ARE FALLING BUT NOT NEARLY AS FAST AS PREVIOUSLY
THOUGHT. OVERNIGHT LOWS ARE STILL EXPECTED 7-9 AM WITH HIGHS 8-10
AM THAT ARE ONLY 1-2 DEGREES ABOVE THE OVERNIGHT LOWS.
TEMPERATURES ARE THEN EXPECTED TO SLOWLY FALL THROUGH THE DAY.
RADAR AND VISIBILITY TRENDS ARE SUGGESTING THE CURRENT VERY LIGHT
PRECIPITATION WILL BE MOVING EAST OF THE MISSISSIPPI THIS MORNING
WITH POSSIBLY SOME FLURRIES. BASED ON DATA FROM THE 12Z
SOUNDING...VERY LIGHT FREEZING DRIZZLE CANNOT BE RULED OUT EITHER.
ALTHOUGH PAVEMENT TEMPERATURES ARE GENERALLY AT OR BELOW
FREEZING...THE STRONG WIND IS PROMOTING EVAPORATION WHICH MAY
LIMIT OR REDUCE ANY FREEZING DRIZZLE ACCUMULATION ON ROADS.
&&
.SYNOPSIS...
ISSUED AT 317 AM CST SUN DEC 29 2013
06Z SFC ANALYSIS HAD A LOW IN CENTRAL WISCONSIN WITH A WEAK TROF
RUNNING FROM THE LOW INTO NORTHEAST MISSOURI. THE ARCTIC FRONT RAN
FROM WESTERN UPPER MICHIGAN...TO KANSAS CITY... AND THEN TO AROUND
KAMA. DEW POINTS ALONG AND AHEAD OF THE ARCTIC FRONT WERE IN THE
20S AND 30S WITH TEENS AND COLDER BEHIND THE FRONT INTO THE PLAINS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CST SUN DEC 29 2013
THE ARCTIC FRONT IS GENERALLY ALONG THE MISSISSIPPI AT 09Z AND
SHOULD BE OVER THE FAR EASTERN AREAS BY SUNRISE. WINDS JUMP
QUICKLY BEHIND THE FRONT WITH SUSTAINED WINDS OF 15 TO 25 MPH WITH
GUSTS OVER 30 MPH. LOW TEMPERATURES THIS MORNING WILL OCCUR 7-9 AM
WITH MAX TEMPERATURES IN THE 8-10 AM TIME FRAME. AT BEST MOST OF
THE AREA WILL ONLY SEEN A 1-2 DEGREE RISE BEFORE TEMPERATURES
START FALLING THROUGH THE DAY.
MOISTURE IN THE LOWER ATMOSPHERE IS NOT AS GREAT AS ORIGINALLY
SUGGESTED. THUS MAINLY FLURRIES WILL BE SEEN DURING THE DAY WITH
SOME AREAS OF LIGHT SNOW. AT BEST ANY ACCUMULATION WOULD BE A DUSTING.
THE CURRENT WIND CHILL ADVISORY HAS BEEN DELAYED UNTIL LATE
MORNING BASED ON EXPECTED TEMPERATURES AND WINDS.
TONIGHT...DRY CONDITIONS ARE EXPECTED AS THE NEXT ARCTIC HIGH
BUILDS INTO THE MIDWEST. BASED ON PROJECTED LOWS AND WIND...AREAS
GENERALLY EAST OF THE CURRENT WIND CHILL ADVISORY WILL MET WIND
CHILL CRITERIA TONIGHT INTO MONDAY MORNING.
AREAS WEST OF A DUBUQUE TO IOWA CITY LINE MAY SEE WIND CHILLS
EXCEED 30 BELOW TONIGHT BEFORE THE ARRIVAL OF THE ARCTIC HIGH. IF
THIS OCCURS...THEN A WIND CHILL WARNING WOULD BE NEEDED FOR THAT
AREA. HOWEVER...TEMPERATURES MAY NOT DROP OFF AS QUICKLY AS
FORECAST AND WINDS MAY NOT BE AS STRONG WHICH WOULD RESULT IN WIND
CHILLS OF ONLY 30 BELOW ZERO. THIS SITUATION WILL HAVE TO BE MONITORED
CAREFULLY DURING THE DAY IN CASE THE ADVISORY WOULD NEED TO BE UPGRADED.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 317 AM CST SUN DEC 29 2013
SNOWIER PATTERN APPEARS IN STORE FOR THE AREA THROUGHOUT THE
EXTENDED AS SEVERAL CLIPPER SYSTEMS ARE SHUTTLED DOWN
OVER THE REGION IN ACTIVE NORTHWEST FLOW.
TEMPS THROUGHOUT THE PERIOD TO REMAIN WELL BELOW NORMAL IN
THE NORTHWEST FLOW. CHALLENGE IN TIME WILL BE IMPACT
OF NEGATIVE FEEDBACK FROM FRESH NEW SNOW COVER ON TEMPS.
IF SOME AREAS SEE 2-5+ INCHES OF NEW SNOW AS IS LOOKING
QUITE REASONABLE AT THIS TIME THEN GOING TEMPS ESPECIALLY
OVER THE LATTER HALF OF THE PERIOD WILL LIKELY NEED TO BE
LOWERED.
FIRST ROUND OF ACCUMULATING SNOW ANTICIPATED MON AFTN/EVE
ESPECIALLY ACROSS THE NORTH 1/2 TO POSSIBLY 2/3RDS OF CWA WITH
CLIPPER SYSTEM AND ATTENDANT WARM ADVECTION. LIQUID PCPN
AMOUNTS LOOK TO BE LIGHT AND LESS THAN 0.1 INCH BUT HIGH SNOW
TO LIQUID RATIOS OF 15-20+:1 SUPPORTIVE OF AN INCH OR TWO
OF ACCUMULATION WITH THE HIGHER AMOUNTS FAVORING AREAS NORTH
OF I-80.
ANOTHER CLIPPER SYSTEM THEN FOLLOWS ABOUT 24+ HRS LATER OR LATE
TUE AFTN/NGT WITH SIMILAR LIGHT QPF AND HIGH RATIO EVENT
FOR ANOTHER INCH OR POSSIBLY TWO OF SNOW ESPECIALLY NEAR TO
NORTH OF I-80.
MODELS ARE THEN COMING INTO BETTER AGREEMENT ON A MUCH STRONGER
SYSTEM FOR WED/WED NGT. BETTER MOISTURE AND GOOD DYNAMICS IN
TERMS OF DIGGING SHORTWAVE AND COUPLED UPPER JET STRUCTURE
SUGGESTIVE OF MODERATE QPF EVENT OF 0.25-0.4 INCH POSSIBLE WHICH
WITH SNOW TO LIQUID RATIOS OF 13-17:1 WOULD RESULT IN 3-6 INCH
POTENTIAL SNOW ACCUMS. STILL WAY EARLY IN THE GAME AND OF COURSE
A LOT OF UNCERTAINTY WITH TRACK... BUT THE MAGNITUDE OF FORCING
AND MOISTURE WILL MAKE THIS ONE TO WATCH IN THE COMING DAYS.
MODELS THEN SUGGEST POTENTIAL OF A QUITE PERIOD LATE WEEK AND
INTO NEXT WEEKEND AS THE FLOW PATTERN APPEARS SET TO UNDERGO
TRANSITION TO SOUTHWESTERLY FLOW BY EARLY NEXT WEEK. LATEST RUNS
OF GFS AND ECMWF THEN SHOW AN EVEN STRONGER SYSTEM EJECTING FROM
THE SOUTHWEST AND THROUGH THE CENTRAL CONUS EARLY NEXT WEEK WHICH
COULD BRING MORE SNOW OR A WINTRY MIX TO THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1112 AM CST SUN DEC 29 2013
BITTERLY COLD NORTHWEST WINDS OF 15 TO 28KTS WILL CONTINUE TO BLOW
THROUGH EARLY EVENING TODAY...ALONG WITH PASSING FLURRIES AND MVFR
CIGS BETWEEN 1500 AND 2500 FT. TOWARDS LATE AFTERNOON...CIGS
SHOULD SCATTER OUT TO A CLEAR SKY LASTING THROUGH THE NIGHT. WINDS
WILL BECOME LIGHT BY LATE EVENING...AND WILL REMAIN LIGHT
NORTHWEST UNTIL MID MORNING MONDAY...WHEN A SHIFT TO LIGHT
SOUTHEAST WINDS ARE EXPECTED AT ALL SITES. THIS WILL ALSO SEE THE
ONSET OF MORE MID CLOUDS...RUNNING AHEAD OF A FAST MOVING STORM
SYSTEM WHICH MAY BRING SNOW TO IOWA AND NORTHERN ILLINOIS MONDAY
AFTERNOON AND NIGHT.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY FROM 5 PM THIS AFTERNOON TO NOON CST MONDAY
FOR CLINTON-DES MOINES-HENRY IA-JACKSON-LOUISA-MUSCATINE-
SCOTT.
WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR BENTON-BUCHANAN-
CEDAR-DELAWARE-DUBUQUE-IOWA-JEFFERSON-JOHNSON-JONES-KEOKUK-
LINN-WASHINGTON.
IL...WIND CHILL ADVISORY FROM 5 PM THIS AFTERNOON TO NOON CST MONDAY
FOR BUREAU-CARROLL-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-
MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.
MO...NONE.
&&
$$
UPDATE...ERVIN
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
842 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 840 AM CST SUN DEC 29 2013
A QUICK UPDATE SENT TO SLIGHTLY CHANGE THE OUTLINE OF WIND CHILL
ADVISORY COUNTIES IN WEST CENTRAL ILLINOIS. WE HAVE ADDED THE
COUNTIES OF DES MOINES...HENDERSON...WARREN...AND MCDONOUGH. WHILE
CRITERIA IS MARGINAL FOR WIND CHILLS...THE COLLABORATION WITH
SURROUNDING OFFICES WILL CONVEY A MUCH MORE CONSISTENT MESSAGE
WITH THE INCLUSION OF THESE COUNTIES.
ERVIN
UPDATE ISSUED AT 726 AM CST SUN DEC 29 2013
BASED ON RADAR DUAL POL DATA IN CONCERT WITH WEAK VISIBILITY
RESTRICTIONS FROM THE LIGHT PRECIPITATION...HAVE ADDED PATCHY
FREEZING DRIZZLE THROUGH MID MORNING TO THE FORECAST.
IF THE TRENDS IN THE RAP ARE CORRECT...THE CURRENT FORCING MOVING
THROUGH THE AREA WITH DRIER AIR ALOFT IS PRODUCING SOME LIGHT SNOW
MIXED WITH VERY LIGHT FREEZING DRIZZLE. THIS SHALLOW MOISTURE
SHOULD EXIT THE AREA SHORTLY AFTER MID MORNING.
ACROSS CENTRAL IOWA...THERE IS ANOTHER AREA OF FORCING BUT THE
MOISTURE IS A BIT DEEPER BASED ON CONDENSATION PRESSURE DEFICITS.
HERE PRECIPITATION IS STILL LIGHT BUT OBSERVATIONS AND RADAR DATA
SUGGEST MORE FLURRIES OR VERY LIGHT SNOW INSTEAD OF FREEZING DRIZZLE.
REGARDING THE CURRENT HEADLINES...THE COLDER AIR IS NOT MOVING IN
AS FAST AS THE SHORT RANGE MODEL TRENDS HAVE BEEN SUGGESTING. THIS
OBSERVATIONAL TREND BRINGS QUESTIONS AS TO WHETHER OR NOT 15 BELOW
ZERO IS ACHIEVABLE TONIGHT IN AREAS WEST OF A DUBUQUE TO IOWA CITY
LINE. IF THIS IS THE CASE...THEN WIND CHILLS WOULD NOT PROBABLY
NOT EXCEED 30 BELOW ZERO EITHER. THIS AREA IS RIGHT ON THE CUSP
BETWEEN AN ADVISORY AND A WARNING FOR WIND CHILL. TRENDS THROUGH
THE DAY WILL BE CRITICAL IN DETERMINING WHICH WAY THE HEADLINE
WILL EVENTUALLY GO FOR TONIGHT.
UPDATE ISSUED AT 532 AM CST SUN DEC 29 2013
TEMPERATURES ARE FALLING BUT NOT NEARLY AS FAST AS PREVIOUSLY
THOUGHT. OVERNIGHT LOWS ARE STILL EXPECTED 7-9 AM WITH HIGHS 8-10
AM THAT ARE ONLY 1-2 DEGREES ABOVE THE OVERNIGHT LOWS.
TEMPERATURES ARE THEN EXPECTED TO SLOWLY FALL THROUGH THE DAY.
RADAR AND VISIBILITY TRENDS ARE SUGGESTING THE CURRENT VERY LIGHT
PRECIPITATION WILL BE MOVING EAST OF THE MISSISSIPPI THIS MORNING
WITH POSSIBLY SOME FLURRIES. BASED ON DATA FROM THE 12Z
SOUNDING...VERY LIGHT FREEZING DRIZZLE CANNOT BE RULED OUT EITHER.
ALTHOUGH PAVEMENT TEMPERATURES ARE GENERALLY AT OR BELOW
FREEZING...THE STRONG WIND IS PROMOTING EVAPORATION WHICH MAY
LIMIT OR REDUCE ANY FREEZING DRIZZLE ACCUMULATION ON ROADS.
&&
.SYNOPSIS...
ISSUED AT 317 AM CST SUN DEC 29 2013
06Z SFC ANALYSIS HAD A LOW IN CENTRAL WISCONSIN WITH A WEAK TROF
RUNNING FROM THE LOW INTO NORTHEAST MISSOURI. THE ARCTIC FRONT RAN
FROM WESTERN UPPER MICHIGAN...TO KANSAS CITY... AND THEN TO AROUND
KAMA. DEW POINTS ALONG AND AHEAD OF THE ARCTIC FRONT WERE IN THE
20S AND 30S WITH TEENS AND COLDER BEHIND THE FRONT INTO THE PLAINS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CST SUN DEC 29 2013
THE ARCTIC FRONT IS GENERALLY ALONG THE MISSISSIPPI AT 09Z AND
SHOULD BE OVER THE FAR EASTERN AREAS BY SUNRISE. WINDS JUMP
QUICKLY BEHIND THE FRONT WITH SUSTAINED WINDS OF 15 TO 25 MPH WITH
GUSTS OVER 30 MPH. LOW TEMPERATURES THIS MORNING WILL OCCUR 7-9 AM
WITH MAX TEMPERATURES IN THE 8-10 AM TIME FRAME. AT BEST MOST OF
THE AREA WILL ONLY SEEN A 1-2 DEGREE RISE BEFORE TEMPERATURES
START FALLING THROUGH THE DAY.
MOISTURE IN THE LOWER ATMOSPHERE IS NOT AS GREAT AS ORIGINALLY
SUGGESTED. THUS MAINLY FLURRIES WILL BE SEEN DURING THE DAY WITH
SOME AREAS OF LIGHT SNOW. AT BEST ANY ACCUMULATION WOULD BE A DUSTING.
THE CURRENT WIND CHILL ADVISORY HAS BEEN DELAYED UNTIL LATE
MORNING BASED ON EXPECTED TEMPERATURES AND WINDS.
TONIGHT...DRY CONDITIONS ARE EXPECTED AS THE NEXT ARCTIC HIGH
BUILDS INTO THE MIDWEST. BASED ON PROJECTED LOWS AND WIND...AREAS
GENERALLY EAST OF THE CURRENT WIND CHILL ADVISORY WILL MET WIND
CHILL CRITERIA TONIGHT INTO MONDAY MORNING.
AREAS WEST OF A DUBUQUE TO IOWA CITY LINE MAY SEE WIND CHILLS
EXCEED 30 BELOW TONIGHT BEFORE THE ARRIVAL OF THE ARCTIC HIGH. IF
THIS OCCURS...THEN A WIND CHILL WARNING WOULD BE NEEDED FOR THAT
AREA. HOWEVER...TEMPERATURES MAY NOT DROP OFF AS QUICKLY AS
FORECAST AND WINDS MAY NOT BE AS STRONG WHICH WOULD RESULT IN WIND
CHILLS OF ONLY 30 BELOW ZERO. THIS SITUATION WILL HAVE TO BE MONITORED
CAREFULLY DURING THE DAY IN CASE THE ADVISORY WOULD NEED TO BE UPGRADED.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 317 AM CST SUN DEC 29 2013
SNOWIER PATTERN APPEARS IN STORE FOR THE AREA THROUGHOUT THE
EXTENDED AS SEVERAL CLIPPER SYSTEMS ARE SHUTTLED DOWN
OVER THE REGION IN ACTIVE NORTHWEST FLOW.
TEMPS THROUGHOUT THE PERIOD TO REMAIN WELL BELOW NORMAL IN
THE NORTHWEST FLOW. CHALLENGE IN TIME WILL BE IMPACT
OF NEGATIVE FEEDBACK FROM FRESH NEW SNOW COVER ON TEMPS.
IF SOME AREAS SEE 2-5+ INCHES OF NEW SNOW AS IS LOOKING
QUITE REASONABLE AT THIS TIME THEN GOING TEMPS ESPECIALLY
OVER THE LATTER HALF OF THE PERIOD WILL LIKELY NEED TO BE
LOWERED.
FIRST ROUND OF ACCUMULATING SNOW ANTICIPATED MON AFTN/EVE
ESPECIALLY ACROSS THE NORTH 1/2 TO POSSIBLY 2/3RDS OF CWA WITH
CLIPPER SYSTEM AND ATTENDANT WARM ADVECTION. LIQUID PCPN
AMOUNTS LOOK TO BE LIGHT AND LESS THAN 0.1 INCH BUT HIGH SNOW
TO LIQUID RATIOS OF 15-20+:1 SUPPORTIVE OF AN INCH OR TWO
OF ACCUMULATION WITH THE HIGHER AMOUNTS FAVORING AREAS NORTH
OF I-80.
ANOTHER CLIPPER SYSTEM THEN FOLLOWS ABOUT 24+ HRS LATER OR LATE
TUE AFTN/NGT WITH SIMILAR LIGHT QPF AND HIGH RATIO EVENT
FOR ANOTHER INCH OR POSSIBLY TWO OF SNOW ESPECIALLY NEAR TO
NORTH OF I-80.
MODELS ARE THEN COMING INTO BETTER AGREEMENT ON A MUCH STRONGER
SYSTEM FOR WED/WED NGT. BETTER MOISTURE AND GOOD DYNAMICS IN
TERMS OF DIGGING SHORTWAVE AND COUPLED UPPER JET STRUCTURE
SUGGESTIVE OF MODERATE QPF EVENT OF 0.25-0.4 INCH POSSIBLE WHICH
WITH SNOW TO LIQUID RATIOS OF 13-17:1 WOULD RESULT IN 3-6 INCH
POTENTIAL SNOW ACCUMS. STILL WAY EARLY IN THE GAME AND OF COURSE
A LOT OF UNCERTAINTY WITH TRACK... BUT THE MAGNITUDE OF FORCING
AND MOISTURE WILL MAKE THIS ONE TO WATCH IN THE COMING DAYS.
MODELS THEN SUGGEST POTENTIAL OF A QUITE PERIOD LATE WEEK AND
INTO NEXT WEEKEND AS THE FLOW PATTERN APPEARS SET TO UNDERGO
TRANSITION TO SOUTHWESTERLY FLOW BY EARLY NEXT WEEK. LATEST RUNS
OF GFS AND ECMWF THEN SHOW AN EVEN STRONGER SYSTEM EJECTING FROM
THE SOUTHWEST AND THROUGH THE CENTRAL CONUS EARLY NEXT WEEK WHICH
COULD BRING MORE SNOW OR A WINTRY MIX TO THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 532 AM CST SUN DEC 29 2013
VERY LIGHT PRECIPITATION...IN THE FORM OF FLURRIES OR POSSIBLY
FZDZ...IS OCCURRING ACROSS IOWA AND NORTHERN ILLINOIS BEHIND THE
ARCTIC FRONT. PRESENT WEATHER SENSORS ON OBSERVATIONS ARE NOT
PICKING UP THE LIGHT PRECIPITATION BUT VISIBILITY SENSORS ARE BY
INDICATING A REDUCTION BELOW 10SM. SO...IFR TO LIFR CONDITIONS
WITH VCSH WILL SLOWLY IMPROVE TO MVFR AND THEN VFR THROUGH 00Z/30.
ARCTIC HIGH PRESSURE BUILDING INTO THE MIDWEST AFT 00Z/30 WILL
RESULT IN VFR CONDITIONS AND WINDS DROPPING UNDER 10 KNOTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY FROM 5 PM THIS AFTERNOON TO NOON CST MONDAY
FOR CLINTON-DES MOINES-HENRY IA-JACKSON-LOUISA-MUSCATINE-
SCOTT.
WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR BENTON-BUCHANAN-
CEDAR-DELAWARE-DUBUQUE-IOWA-JEFFERSON-JOHNSON-JONES-KEOKUK-
LINN-WASHINGTON.
IL...WIND CHILL ADVISORY FROM 5 PM THIS AFTERNOON TO NOON CST MONDAY
FOR BUREAU-CARROLL-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-
MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.
MO...NONE.
&&
$$
UPDATE...ERVIN
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
740 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 726 AM CST SUN DEC 29 2013
BASED ON RADAR DUAL POL DATA IN CONCERT WITH WEAK VISIBILITY
RESTRICTIONS FROM THE LIGHT PRECIPITATION...HAVE ADDED PATCHY
FREEZING DRIZZLE THROUGH MID MORNING TO THE FORECAST.
IF THE TRENDS IN THE RAP ARE CORRECT...THE CURRENT FORCING MOVING
THROUGH THE AREA WITH DRIER AIR ALOFT IS PRODUCING SOME LIGHT SNOW
MIXED WITH VERY LIGHT FREEZING DRIZZLE. THIS SHALLOW MOISTURE
SHOULD EXIT THE AREA SHORTLY AFTER MID MORNING.
ACROSS CENTRAL IOWA...THERE IS ANOTHER AREA OF FORCING BUT THE
MOISTURE IS A BIT DEEPER BASED ON CONDENSATION PRESSURE DEFICITS.
HERE PRECIPITATION IS STILL LIGHT BUT OBSERVATIONS AND RADAR DATA
SUGGEST MORE FLURRIES OR VERY LIGHT SNOW INSTEAD OF FREEZING DRIZZLE.
REGARDING THE CURRENT HEADLINES...THE COLDER AIR IS NOT MOVING IN
AS FAST AS THE SHORT RANGE MODEL TRENDS HAVE BEEN SUGGESTING. THIS
OBSERVATIONAL TREND BRINGS QUESTIONS AS TO WHETHER OR NOT 15 BELOW
ZERO IS ACHIEVABLE TONIGHT IN AREAS WEST OF A DUBUQUE TO IOWA CITY
LINE. IF THIS IS THE CASE...THEN WIND CHILLS WOULD NOT PROBABLY
NOT EXCEED 30 BELOW ZERO EITHER. THIS AREA IS RIGHT ON THE CUSP
BETWEEN AN ADVISORY AND A WARNING FOR WIND CHILL. TRENDS THROUGH
THE DAY WILL BE CRITICAL IN DETERMINING WHICH WAY THE HEADLINE
WILL EVENTUALLY GO FOR TONIGHT.
UPDATE ISSUED AT 532 AM CST SUN DEC 29 2013
TEMPERATURES ARE FALLING BUT NOT NEARLY AS FAST AS PREVIOUSLY
THOUGHT. OVERNIGHT LOWS ARE STILL EXPECTED 7-9 AM WITH HIGHS 8-10
AM THAT ARE ONLY 1-2 DEGREES ABOVE THE OVERNIGHT LOWS.
TEMPERATURES ARE THEN EXPECTED TO SLOWLY FALL THROUGH THE DAY.
RADAR AND VISIBILITY TRENDS ARE SUGGESTING THE CURRENT VERY LIGHT
PRECIPITATION WILL BE MOVING EAST OF THE MISSISSIPPI THIS MORNING
WITH POSSIBLY SOME FLURRIES. BASED ON DATA FROM THE 12Z
SOUNDING...VERY LIGHT FREEZING DRIZZLE CANNOT BE RULED OUT EITHER.
ALTHOUGH PAVEMENT TEMPERATURES ARE GENERALLY AT OR BELOW
FREEZING...THE STRONG WIND IS PROMOTING EVAPORATION WHICH MAY
LIMIT OR REDUCE ANY FREEZING DRIZZLE ACCUMULATION ON ROADS.
&&
.SYNOPSIS...
ISSUED AT 317 AM CST SUN DEC 29 2013
06Z SFC ANALYSIS HAD A LOW IN CENTRAL WISCONSIN WITH A WEAK TROF
RUNNING FROM THE LOW INTO NORTHEAST MISSOURI. THE ARCTIC FRONT RAN
FROM WESTERN UPPER MICHIGAN...TO KANSAS CITY... AND THEN TO AROUND
KAMA. DEW POINTS ALONG AND AHEAD OF THE ARCTIC FRONT WERE IN THE
20S AND 30S WITH TEENS AND COLDER BEHIND THE FRONT INTO THE PLAINS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CST SUN DEC 29 2013
THE ARCTIC FRONT IS GENERALLY ALONG THE MISSISSIPPI AT 09Z AND
SHOULD BE OVER THE FAR EASTERN AREAS BY SUNRISE. WINDS JUMP
QUICKLY BEHIND THE FRONT WITH SUSTAINED WINDS OF 15 TO 25 MPH WITH
GUSTS OVER 30 MPH. LOW TEMPERATURES THIS MORNING WILL OCCUR 7-9 AM
WITH MAX TEMPERATURES IN THE 8-10 AM TIME FRAME. AT BEST MOST OF
THE AREA WILL ONLY SEEN A 1-2 DEGREE RISE BEFORE TEMPERATURES
START FALLING THROUGH THE DAY.
MOISTURE IN THE LOWER ATMOSPHERE IS NOT AS GREAT AS ORIGINALLY
SUGGESTED. THUS MAINLY FLURRIES WILL BE SEEN DURING THE DAY WITH
SOME AREAS OF LIGHT SNOW. AT BEST ANY ACCUMULATION WOULD BE A DUSTING.
THE CURRENT WIND CHILL ADVISORY HAS BEEN DELAYED UNTIL LATE
MORNING BASED ON EXPECTED TEMPERATURES AND WINDS.
TONIGHT...DRY CONDITIONS ARE EXPECTED AS THE NEXT ARCTIC HIGH
BUILDS INTO THE MIDWEST. BASED ON PROJECTED LOWS AND WIND...AREAS
GENERALLY EAST OF THE CURRENT WIND CHILL ADVISORY WILL MET WIND
CHILL CRITERIA TONIGHT INTO MONDAY MORNING.
AREAS WEST OF A DUBUQUE TO IOWA CITY LINE MAY SEE WIND CHILLS
EXCEED 30 BELOW TONIGHT BEFORE THE ARRIVAL OF THE ARCTIC HIGH. IF
THIS OCCURS...THEN A WIND CHILL WARNING WOULD BE NEEDED FOR THAT
AREA. HOWEVER...TEMPERATURES MAY NOT DROP OFF AS QUICKLY AS
FORECAST AND WINDS MAY NOT BE AS STRONG WHICH WOULD RESULT IN WIND
CHILLS OF ONLY 30 BELOW ZERO. THIS SITUATION WILL HAVE TO BE MONITORED
CAREFULLY DURING THE DAY IN CASE THE ADVISORY WOULD NEED TO BE UPGRADED.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 317 AM CST SUN DEC 29 2013
SNOWIER PATTERN APPEARS IN STORE FOR THE AREA THROUGHOUT THE
EXTENDED AS SEVERAL CLIPPER SYSTEMS ARE SHUTTLED DOWN
OVER THE REGION IN ACTIVE NORTHWEST FLOW.
TEMPS THROUGHOUT THE PERIOD TO REMAIN WELL BELOW NORMAL IN
THE NORTHWEST FLOW. CHALLENGE IN TIME WILL BE IMPACT
OF NEGATIVE FEEDBACK FROM FRESH NEW SNOW COVER ON TEMPS.
IF SOME AREAS SEE 2-5+ INCHES OF NEW SNOW AS IS LOOKING
QUITE REASONABLE AT THIS TIME THEN GOING TEMPS ESPECIALLY
OVER THE LATTER HALF OF THE PERIOD WILL LIKELY NEED TO BE
LOWERED.
FIRST ROUND OF ACCUMULATING SNOW ANTICIPATED MON AFTN/EVE
ESPECIALLY ACROSS THE NORTH 1/2 TO POSSIBLY 2/3RDS OF CWA WITH
CLIPPER SYSTEM AND ATTENDANT WARM ADVECTION. LIQUID PCPN
AMOUNTS LOOK TO BE LIGHT AND LESS THAN 0.1 INCH BUT HIGH SNOW
TO LIQUID RATIOS OF 15-20+:1 SUPPORTIVE OF AN INCH OR TWO
OF ACCUMULATION WITH THE HIGHER AMOUNTS FAVORING AREAS NORTH
OF I-80.
ANOTHER CLIPPER SYSTEM THEN FOLLOWS ABOUT 24+ HRS LATER OR LATE
TUE AFTN/NGT WITH SIMILAR LIGHT QPF AND HIGH RATIO EVENT
FOR ANOTHER INCH OR POSSIBLY TWO OF SNOW ESPECIALLY NEAR TO
NORTH OF I-80.
MODELS ARE THEN COMING INTO BETTER AGREEMENT ON A MUCH STRONGER
SYSTEM FOR WED/WED NGT. BETTER MOISTURE AND GOOD DYNAMICS IN
TERMS OF DIGGING SHORTWAVE AND COUPLED UPPER JET STRUCTURE
SUGGESTIVE OF MODERATE QPF EVENT OF 0.25-0.4 INCH POSSIBLE WHICH
WITH SNOW TO LIQUID RATIOS OF 13-17:1 WOULD RESULT IN 3-6 INCH
POTENTIAL SNOW ACCUMS. STILL WAY EARLY IN THE GAME AND OF COURSE
A LOT OF UNCERTAINTY WITH TRACK... BUT THE MAGNITUDE OF FORCING
AND MOISTURE WILL MAKE THIS ONE TO WATCH IN THE COMING DAYS.
MODELS THEN SUGGEST POTENTIAL OF A QUITE PERIOD LATE WEEK AND
INTO NEXT WEEKEND AS THE FLOW PATTERN APPEARS SET TO UNDERGO
TRANSITION TO SOUTHWESTERLY FLOW BY EARLY NEXT WEEK. LATEST RUNS
OF GFS AND ECMWF THEN SHOW AN EVEN STRONGER SYSTEM EJECTING FROM
THE SOUTHWEST AND THROUGH THE CENTRAL CONUS EARLY NEXT WEEK WHICH
COULD BRING MORE SNOW OR A WINTRY MIX TO THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 532 AM CST SUN DEC 29 2013
VERY LIGHT PRECIPITATION...IN THE FORM OF FLURRIES OR POSSIBLY
FZDZ...IS OCCURRING ACROSS IOWA AND NORTHERN ILLINOIS BEHIND THE
ARCTIC FRONT. PRESENT WEATHER SENSORS ON OBSERVATIONS ARE NOT
PICKING UP THE LIGHT PRECIPITATION BUT VISIBILITY SENSORS ARE BY
INDICATING A REDUCTION BELOW 10SM. SO...IFR TO LIFR CONDITIONS
WITH VCSH WILL SLOWLY IMPROVE TO MVFR AND THEN VFR THROUGH 00Z/30.
ARCTIC HIGH PRESSURE BUILDING INTO THE MIDWEST AFT 00Z/30 WILL
RESULT IN VFR CONDITIONS AND WINDS DROPPING UNDER 10 KNOTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY FROM 5 PM THIS AFTERNOON TO NOON CST MONDAY
FOR CLINTON-HENRY IA-JACKSON-LOUISA-MUSCATINE-SCOTT.
WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR BENTON-BUCHANAN-
CEDAR-DELAWARE-DUBUQUE-IOWA-JEFFERSON-JOHNSON-JONES-KEOKUK-
LINN-WASHINGTON.
IL...WIND CHILL ADVISORY FROM 5 PM THIS AFTERNOON TO NOON CST MONDAY
FOR BUREAU-CARROLL-HENRY IL-JO DAVIESS-MERCER-PUTNAM-ROCK
ISLAND-STEPHENSON-WHITESIDE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1010 PM MST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 117 PM MST SAT DEC 28 2013
THE LAST WEEKEND OF 2013 KICKED OFF YESTERDAY WITH WELL ABOVE-NORMAL
TEMPERATURES AND WILL END WITH A VERY COLD SUNDAY. AN ARCTIC COLD
FRONT ON THE WAY TODAY WILL BRING THE COLD AIR AS WELL AS STRONG
WINDS. A FEW FLURRIES ARE POSSIBLE TONIGHT INTO EARLY SUNDAY...BUT
THE MAIN IMPACT OF THIS FRONT WILL BE THE WIND AND COLD. ON SUNDAY
SKIES WILL BECOME MOSTLY SUNNY BUT TEMPERATURES WILL HAVE A TOUGH
TIME GETTING ABOVE FREEZING.
TODAY...SATURDAY...SUNNY AND MILD TO START...BECOMING WINDY AND
COLD. FRONTAL PASSAGE LOOKS TO OCCUR IN THE EARLY AFTERNOON...WITH A
REINFORCING SHOT OF COLD AIR TONIGHT. AHEAD OF THE FRONT IT WILL BE
A NICE DAY SIMILAR TO YESTERDAY WITH SUNNY SKIES...MILD TEMPS...AND
A LIGHT WEST/SOUTHWESTERLY WIND. HIGHS MIGHT EVEN APPROACH RECORD
VALUES TODAY WHICH ARE IN THE MID TO UPPER 60S FOR MOST STATIONS. /RECORD
HIGH OF 67 AT HILL CITY LOOKS TO HAVE THE BEST CHANCE OF BEING
BROKEN OUT OF THE FOUR ASOS SITES./ THE INITIAL FRONT WILL RACE
SOUTH ACROSS THE REGION EARLY THIS AFTERNOON...BRINGING GUSTY WINDS.
DECIDED TO REMOVE THE BLOWING DUST FROM THE WX GRID AS EXPECT ANY
BLOWING DUST/DIRT TO BE VERY LIMITED SPATIALLY/TEMPORALLY BASED ON
THE LATEST SHORT-TERM GUIDANCE. MID/HIGH LEVEL CLOUD COVER
ASSOCIATED WITH THE FRONT WILL ARRIVE LATER THIS AFTERNOON...WITH
LOW-LEVEL STRATUS CLOUDS THIS EVENING.
TONIGHT...STRONG PRESSURE RISES SUPPORT WINDY CONDITIONS THROUGH THE
NIGHT WITH LIGHT SNOW POSSIBLE IN EASTERN COLORADO. OVERCAST SKIES
WITH A LOW STRATUS DECK IN THE EVENING AND MID-LEVEL CLOUDS
PERSISTING THROUGH MOST OF THE NIGHT. WINDS WILL CONTINUE AS STRONG
PRESSURE RISES /5-8 MB/HR/ ARE EXPECTED AND MIXING OCCURS. A FEW
FLURRIES/LIGHT SNOW POSSIBLE IN EASTERN COLORADO AND PORTIONS OF NW
KANSAS WITH THE COMBINATION OF LOW LEVEL MOISTURE AND
FRONTOGENETICAL FORCING IN PLACE. GUIDANCE HAS BEEN QUITE CONSISTENT
RUN-TO-RUN...AND EARLY NCEP RAP AND ESRL RAP RUNS SUPPORT AT LEAST
SOME FLURRIES FOR MOST SPOTS. ACCUMULATIONS ARE NOT EXPECTED TO
AMOUNT TO MUCH...BUT WOULD NOT BE SURPRISED IF WESTERN PARTS OF
CHEYENNE/KIT CARSON COUNTIES IN COLORADO RECEIVE A HALF INCH.
/THOUGH IT WILL BE HARD TO MEASURE WITH ALL THE WIND.../ LOWS WILL
REACH THE SINGLE DIGITS IN MANY LOCATIONS WITH 850MB TEMPS IN THE
-12 TO -15 C RANGE AND STRONG COLD AIR ADVECTION.
TOMORROW...SUNDAY...COLD AND MOSTLY SUNNY. AT DAWN SUNDAY CLOUDS
WILL BE CLEARING FROM NORTHWEST TO SOUTHEAST...BECOMING MOSTLY SUNNY
EVERYWHERE BY THE AFTERNOON. WINDS WILL BE LIGHT OUT OF THE
NORTH/NORTHWEST AT 10 TO 15 MPH. DESPITE THE SUN HIGHS WILL STRUGGLE
TO REACH ABOVE FREEZING AS HIGH PRESSURE STRENGTHENS ACROSS THE
NORTHERN PLAINS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 200 PM MST SAT DEC 28 2013
SUNDAY NIGHT-TUESDAY...PERIODIC INCREASES IN MID AND HIGH CLOUDS
EXPECTED UNDER NORTHWEST FLOW ALOFT. NO PRECIPITATION EXPECTED. MAY
SEE SOME BREEZY NORTHWEST WINDS MONDAY AFTERNOON.
LOWS SUNDAY NIGHT AROUND 10 ACROSS THE EAST AND WESTERN PORTIONS OF
CHEYENNE COUNTY COLORADO...LOW TO MID TEENS ELSEWHERE. HIGHS MONDAY
MID 40S TO AROUND 50. MAY HAVE A BIT OF SNOW COVER TO DEAL WITH
ACROSS THE WEST AND HAVE MID 40S IN THAT AREA. ON TUESDAY 850
TEMPERATURES WARM ABOUT 13-15F ACROSS THE AREA SUPPORTING HIGHS IN
THE MID 50S (NORTHEAST) TO MID 60S (WEST). BIAS CORRECTED GRIDS
ALONG THE 2M/MET/MAV ARE SEVERAL DEGREES COOLER. HAVE GENERALLY
BLENDED ALL SOLUTIONS TRYING TO TREND A BIT CLOSER TO 850
TEMPERATURES. HAVE SETTLED ON LOW TO MID 50S FAR NORTHEAST-EAST WITH
UPREAR 50S TO AROUND 60 ACROSS THE WESTERN/SOUTHWESTERN 2/3 OF THE
AREA.
TUESDAY NIGHT-SATURDAY...THERE IS A SLIGHT CHANCE OF LIGHT
PRECIPITATION WEDNESDAY AS A LARGE AREA OF MOISTURE MOVES IN FROM
THE NORTHWEST...AIDED BY APPROACHING LEFT FRONT PORTION OF UPPER
JET. BETTER CHANCES OF PRECIP GENERALLY ACROSS NORTHEAST 1/2 OF THE
FORECAST AREA. THIS SYSTEM EXITS THE AREA EARLY WEDNESDAY NIGHT.
OTHERWISE...A DRY FORECAST EXPECTED. LOWS THROUGH THURSDAY NIGHT IN
THE TEENS TO LOW 20S WITH MID 20S FRIDAY NIGHT. HIGHS WEDNESDAY IN
THE LOW 30S EAST TO LOW/MID 40S FAR WEST...SLOWLY WARMING INTO THE
LOW TO MID 40S (EAST TO WEST) THURSDAY. ON FRIDAY WE SHOULD RETURN
TO ABOVE NORMAL TEMPERATURES WITH UPPER 40S TO MID 50S. A RETURN TO
NEAR NORMAL HIGHS SATURDAY WITH LOW TO MID 40S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1005 PM MST SAT DEC 28 2013
AT KGLD...CEILINGS HAVE BEEN BOUNCING BETWEEN VFR AND MVFR ALL
EVENING BUT SHOULD SETTLE MORE IN THE MVFR CATEGORY DURING THE
OVERNIGHT HOURS. THERE WILL BE A CHANCE FOR LIGHT SNOW AS WELL
WHICH COULD BRIEFLY REDUCE VISIBILITY TO AROUND 5SM. FLIGHT
CATEGORIES WILL QUICKLY IMPROVE AROUND SUNRISE AS UPPER SYSTEM
MOVES OUT. SURFACE WINDS WILL BE BREEZY TO WINDY THROUGH THE
OVERNIGHT...DIMINISHING SUNDAY MORNING.
AT KMCK...VFR WILL BE THE PRIMARY FLIGHT CATEGORY ALTHOUGH CANT
RULE OUT A BRIEF CEILING REDUCTION OVERNIGHT TO MVFR. NO
PRECIPITATION IS EXPECTED. SURFACE WINDS WILL BE BREEZY TO WINDY
THROUGH THE OVERNIGHT...DIMINISHING SUNDAY MORNING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...99
AVIATION...024
AREA FORECAST DISCUSSION
NWS GRAY ME
333 PM EST SUN DEC 29 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE RAPIDLY THROUGH THE GULF OF MAINE TONIGHT
AND WILL BE LOCATED NEAR HALIFAX NOVA SCOTIA BY MONDAY MORNING.
HIGH PRESSURE WILL BUILD OVER THE REGION MONDAY. WEAK LOW PRESSURE
WILL MOVE THROUGH CENTRAL NEW ENGLAND TUESDAY AFTERNOON. HIGH
PRESSURE WILL BUILD OVER THE REGION WEDNESDAY. LOW PRESSURE WILL
GATHER STRENGTH OVER THE MID ATLANTIC STATES THURSDAY AND MOVE
NORTHEAST SOUTH OF CAPE COD FRIDAY. HIGH PRESSURE WILL BUILD OVER
THE NORTHEAST SATURDAY AND MOVE SOUTHEAST OF THE REGION SUNDAY.
&&
.NEAR TERM /TONIGHT/...
COLD FRONT HAS PUSHED SOUTH THROUGH THE MIDCOAST AND IS NOW
LOCATED FROM WISCASSET TO LEWISTON BEFORE GETTING HUNG UP IN THE
HILL COUNTRY NEAR RUMFORD. TEMPERATURES BEHIND THE FRONT HAVE BEEN
FALLING INTO THE MID 20S AS NOTED OVER THE PAST FEW HOURS AT
BANGOR AND WATERVILLE. THIS FRONT MAY PLAY A KEY ROLE IN
DETERMINING PRECIPITATION TYPE ACROSS THE MIDCOAST REGION TONIGHT.
LOW PRESSURE CURRENTLY JUST SOUTHEAST OF PHILADELPHIA WILL TRACK
QUICKLY NORTHEAST ACROSS CAPE COD AND TO NOVA SCOTIA TONIGHT.
LARGE AREA OF PRECIPITATION HAS SPREAD NORTHWARD AHEAD OF THIS
LOW... NOW SPREADING ACROSS ALL OF SOUTHERN NEW ENGLAND AND
PUSHING INTO SOUTHERN NEW HAMPSHIRE. THIS PRECIPITATION WILL
CONTINUE TO SPREAD NORTHEAST ACROSS NEW HAMPSHIRE AND MAINE
OVERNIGHT... BRINGING A QUICK... BUT HEAVY... ROUND OF
PRECIPITATION BEFORE EXITING JUST AFTER MIDNIGHT.
PRECIPITATION TYPE CONTINUES TO BE A COMPLEX PICTURE WITH THIS
STORM... AS TEMPERATURES THROUGH THE LOWEST FEW THOUSAND FEET WILL
BE NEAR FREEZING ACROSS MUCH OF SOUTHERN NEW HAMPSHIRE AND COASTAL
MAINE. NAM AND HRRR MODELS CONTINUE TO SHOW A COLDER SOLUTION...
WITH TEMPERATURES AT OR JUST BELOW FREEZING AS PRECIPITATION FALLS
THIS EVENING. IT IS EXPECTED THAT AS PRECIPITATION BEGINS TO
INTENSIFY... TEMPERATURES WITHIN THE ATMOSPHERIC PROFILE WILL COOL
AND ALLOW A HEAVY WET SNOW TO FALL. LOTS OF MOISTURE AND GOOD
DYNAMICS WITH THIS SYSTEM WILL ALLOW INTENSE PRECIPITATION
RATES... WITH TOTAL QPF TONIGHT RANGING FROM 0.75 TO 1.00 INCH.
SNOW RATIOS WILL BE NEAR 10 TO 1 DUE TO THE LARGE ISOTHERMAL LAYER
IN THE LOW LEVELS ESPECIALLY OVER SOUTHERN AND CENTRAL NEW
HAMPSHIRE EXTENDING TO THE MAINE COAST. NORTH OF THE PREVIOUSLY
MENTIONED COLD FRONT... TEMPERATURES WILL BE A BIT COLDER...
LEADING TO MORE CERTAINTY THAT PRECIPITATION WILL FALL IN THE FORM
OF SNOW AND ALLOW SNOW RATIOS TO BE A BIT HIGHER... POSSIBLY 13 TO
1.
THERE IS A GOOD AMOUNT OF CONFIDENCE THAT A BAND OF 6 TO 10 INCHES
OF SNOW WILL FALL... THOUGH THE TRANSITION TO RAIN NEAR THE COAST
IS STILL THE BIGGEST QUESTION MARK. IT IS POSSIBLE THAT THE
IMMEDIATE COASTLINE MAY SEE ONLY AN INCH OR TWO OF SNOW WHILE
AREAS JUST INLAND COULD SEE 6 TO 10. WITH THE COLDER FORECAST...
THE WINTER STORM WARNINGS HAVE BEEN EXTENDED TO THE COAST FROM
PORTLAND EASTWARD. THIS AREA WAS ALSO HIT HARD BY THE ICE STORM
LAST WEEKEND AND THE TREES ARE LIKELY STILL SUPPORTING A LOAD OF
ICE FROM THIS. WITH THE ADDITIONAL STICKY... WET SNOW EXPECTED...
THIS COULD CAUSE ADDITIONAL POWER OUTAGES EVEN IF THE 6 INCH
WARNING CRITERIA IS NOT MET.
SNOWFALL RATES WILL LIKELY BE QUITE INTENSE THIS EVENING... WITH 1
TO 2 INCHES PER HOUR COMMON AND RATES UP TO 3 INCHES PER HOUR
POSSIBLE. THIS WILL MAKE IT MORE DIFFICULT FOR ROAD CREWS TO KEEP
UP WITH SNOW REMOVAL DURING THE HEAVIEST PERIOD OF SNOW... CAUSING
EVEN GREATER IMPACTS ON TRAVEL. ALL THESE FACTORS WERE CONSIDERED
IN THE PLACING OF WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES.
FURTHER TO THE NORTH... THERE WILL LIKELY BE A SHARP CUT OFF IN
SNOWFALL AMOUNTS INLAND OF THE HEAVIEST BAND. LOCATIONS NEAR THE
CANADIAN BORDER MAY NOT SEE MUCH SNOW AT ALL... AND NORTHERN COOS
COUNTY HAS BEEN DROPPED FROM THE ADVISORY AS FORECAST SNOWFALL
AMOUNTS IN THIS REGION ARE ONLY 1 TO 2 INCHES. THE NORTHERN ZONES
IN WESTERN MAINE WERE LEFT IN AS THE SOUTHERN PORTION OF THESE
ZONES STILL HAS A THREAT FOR HIGHER TOTALS.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS LOW PRESSURE MOVES EAST... A COLD FRONT WILL PUSH SOUTHEAST
ACROSS NEW ENGLAND ON MONDAY. A VERY COLD AIR MASS HAS BEEN
LURKING BEHIND THIS FRONT... AND THIS WILL BE FELT IN FULL FORCE
BY MONDAY AFTERNOON. TEMPERATURES WILL LIKELY BE FALLING THROUGH
THE DAY AS COLD ADVECTION TAKES OVER. WINDS COULD GUST TO 25 MPH
AS COLD ADVECTION ALLOWS GOOD MIXING TO TAKE PLACE.
TEMPERATURES FALL TO NEAR OR BELOW ZERO ACROSS THE ENTIRE FORECAST
AREA MONDAY NIGHT. READINGS AS COLD AS 20 BELOW ARE POSSIBLE TO
THE NORTH OF THE MOUNTAINS WHERE COLD AIR WILL BE EVEN MORE
INTENSE. WIND CHILL ADVISORIES OR WARNINGS MAY BE NEEDED AS WIND
CHILLS COULD REACH 30 BELOW.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MODELS IN AGREEMENT THROUGH THE PERIOD FOR A COLD WEEK. A WEAK SHORT
WAVE WILL MOVE THROUGH NEW HAMPSHIRE AND MAINE TUESDAY AFTERNOON
WITH ASSOCIATED SNOW SHOWERS AND USHER IN EVEN COLDER AIR. WIND
CHILL ADVISORIES MAY BE NEEDED TUESDAY NIGHT AND WEDNESDAY. HIGH
PRESSURE CRESTS OVERHEAD WEDNESDAY. LATE IN THE DAY CLOUDS STREAM
EAST. LIGHT SNOW DEVELOPS THURSDAY AS LOW PRESSURE DEVELOPS SOUTH
OF LONG ISLAND NEW YORK. GFS AND ECMWF SIMILAR IN THE TRACK AND
LINGER SNOW INTO FRIDAY. SEVERAL INCHES OF SNOW POSSIBLE WITH THIS
SYSTEM. ANOTHER ARCTIC SHOT OF AIR ARRIVES FRIDAY AFTERNOON AND
SATURDAY. A WARM FRONT WILL MOVE NORTH SUNDAY.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
SHORT TERM...THERE WILL LIKELY BE A PERIOD OF HEAVY SNOW AT
SOUTHERN AND COASTAL TERMINALS FROM CONCORD TO PORTLAND TO AUGUSTA
THIS EVENING. PORTSMOUTH MAY NOT SEE THIS HEAVY SNOW AS
PRECIPITATION COULD STAY AS RAIN. EXPECT LIFR CONDITIONS FOR A
TIME BEFORE VFR RETURNS AFTER MIDNIGHT. NORTHWEST WINDS ON MONDAY
COULD GUST TO 25 KT.
LONG TERM...POSSIBLE MVFR IN SNOW SHOWERS TUESDAY AND WEDNESDAY.
IFR MOVES IN THURSDAY AFTERNOON AND MOVES OUT FRIDAY. VFR
SATURDAY AND SUNDAY.
&&
.MARINE...
SHORT TERM...LOW PRESSURE MOVING FROM CAPE COD TO NOVA SCOTIA WILL
BRING A BRIEF PERIOD OF NORTHEAST WINDS WHICH COULD GUST TO GALE
FORCE. WINDS SHIFT TO NORTHWEST BY MORNING. A COLD FRONT PUSHING
THROUGH THE GULF OF MAINE ON MONDAY WILL BRING STRONG COLD
ADVECTION AND THE POTENTIAL FOR MORE GALE FORCE GUSTS THROUGH
MONDAY EVENING.
LONG TERM...SMALL CRAFT WINDS TUESDAY AND WEDNESDAY. GALE FORCE
WINDS POSSIBLE THURSDAY AFTERNOON INTO SATURDAY MORNING.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING UNTIL 4 AM EST MONDAY FOR MEZ012>014-
018>022-024>028.
WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR MEZ007>009-
023.
NH...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR NHZ004>010.
WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR NHZ002-003.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NHZ013.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 9 PM EST MONDAY
FOR ANZ151-153.
GALE WARNING FROM 6 PM THIS EVENING TO 9 PM EST MONDAY FOR
ANZ150-152-154.
&&
$$
SHORT TERM... KIMBLE
LONG TERM... HAWLEY
AREA FORECAST DISCUSSION
NWS GRAY ME
1048 AM EST SUN DEC 29 2013
.SYNOPSIS...
A COLD FRONT WILL BECOME STATIONARY OVER SOUTHERN PORTIONS OF
MAINE AND NEW HAMPSHIRE THIS MORNING. LOW PRESSURE WILL REACH THE
MID ATLANTIC COASTLINE THIS AFTERNOON...BEFORE PASSING OVER CAPE
COD THIS EVENING AND THROUGH THE GULF OF MAINE TONIGHT. HIGH
PRESSURE WILL BUILD INTO THE REGION MONDAY...WITH A WEAK WEATHER
DISTURBANCE CROSSING THE WATERS ON TUESDAY. LOW PRESSURE WILL
GRADUALLY APPROACH THE EAST ON WEDNESDAY...BEFORE INTENSIFYING OFF
THE MID ATLANTIC COAST ON THURSDAY.
&&
.NEAR TERM /TODAY/...
LATE MORNING UPDATE...
HAVE PERFORMED A MAJOR REWORK OF THE FORECAST FOR TODAY AND
TONIGHT PRIMARILY TO IMPROVE CONSISTENCY IN THE FORECAST AND
HEADLINES. TEMPERATURES TODAY ARE A LITTLE COOLER THAN EXPECTED...
AND THE COLD FRONT HAS NOW PUSHED SOUTH THROUGH BANGOR. HRRR AND
NAM MODELS WHICH ARE SOME OF THE HIGHER RESOLUTION MODELS
AVAILABLE... NOW SHOW A COLDER FORECAST DURING THE EVENT LATER
TODAY AND TONIGHT... RESULTING IN A QUICKER TRANSITION TO SNOW FOR
SOME AREAS. HAVE TRENDED TOWARD THIS IDEA... THOUGH STILL MAINTAIN
THAT COASTAL AREAS WILL LIKELY SEE MORE RAIN THAN SNOW. SNOW WILL
BE A HEAVY... STICKY... WET SNOW AND MAY CAUSE ADDITIONAL PROBLEMS
DUE TO THE WEIGHT OF THIS SNOW ON TREES. SNOWFALL RATES COULD BE 1
TO 2 INCHES PER HOUR... OR EVEN HIGHER AT TIMES. INTENSE SNOWFALL
RATES COULD ACTUALLY BE ENOUGH TO FORCE THE CHANGE OVER FROM RAIN
TO SNOW FOR MORE AREAS. SNOW BEGINS TO REACH SOUTHERN AREAS BY
AROUND 4 PM... WITH THE HEAVIEST SNOW FALLING FROM 6 PM TO
MIDNIGHT. HAVE EXPANDED THE WINTER STORM WARNINGS TO INCLUDE MORE
AREAS OF SOUTHERN AND WESTERN NEW HAMPSHIRE WHERE THE HEAVIER BAND
SHOULD SET UP LATER TODAY. THERE COULD BE A SHARP DROP OFF IN SNOW
TOTALS ON THE NORTHERN EDGE ALSO... WITH FAR NORTHERN AREAS
POSSIBLY SEEING LESS THAN 4 INCHES.
EARLY MORNING UPDATE...
HAVE UPDATED GRIDS BASED ON CURRENT CONDITIONS. BACKDOOR COLD
FRONT CONTINUES TO PRESS SOUTH AND WEST TOWARDS OUR AREA. THIS
FRONT SHOULD SLOW DOWN OVER THE NEXT FEW HOURS. CLOUDS WILL
CONTINUE TO INCREASE AND THICKEN THIS MORNING. PRECIPITATION TO
OVERSPREAD THE REGION LATER THIS AFTERNOON AND EARLY THIS EVENING.
ORIGINAL DISCUSSION...
CLOUDS WILL CONTINUE TO INCREASE AND THICKEN TODAY FROM
SOUTH TO NORTH...WITH PATCHY FOG EARLY. AT THE SAME TIME...A
BACKDOOR COLD FRONT WILL ALLOW ARCTIC AIR TO POUR INTO NORTHERN
MAINE. THIS COLD AIR WILL SETTLE SOUTHWARD...AS THE FRONT STALLS
OVER SOUTHERN SECTIONS THIS AFTERNOON AS THE PRECIPITATION...JUST
AS THE NEXT SYSTEM ENTERS THE REGION. THE PRECIPITATION WILL
LIKELY BEGIN AS LIGHT RAIN OVER SOUTHERN AREAS LATE THIS AFTERNOON
IN A NEARLY ISOTHERMAL ATMOSPHERIC LAYERS.
USED A BLEND OF WRMEMS/SREF AND NAM12 FOR DAYTIME MAXES.
&&
.SHORT TERM /TONIGHT AND MONDAY/...
VERY INTERESTING SITUATION WILL UNFOLD EARLY THIS EVENING AS
VERTICAL MOTIONS INCREASE RAPIDLY AHEAD OF COASTAL LOW NEAR LONG
ISLAND NEW YORK. A DEGREE OR TWO EITHER WAY IN OUR LOW LEVEL
SOUNDINGS WILL HAVE SIGNIFICANT RAMIFICATIONS OVER SOUTHERN
AREAS. TIMING AND PENETRATION OF ARCTIC AIR WILL REMAIN CRITICAL
AS WELL. USED A BLEND OF MODEL GUIDANCE AND CONCEPTUAL MODEL OF
THIS FAST PACED EVENT...WILL ALLOW FOR LITTLE IN THE WAY OF
SNOWFALL ALONG THE IMMEDIATE SHORELINE AS MUCH OF THE PRECIP WILL
FALL IN THE FORM OF RAIN. HOWEVER...THERE WILL BE A SHARP GRADIENT
AS YOU HEAD JUST 10-20 MILES NORTH AWAY FROM THE COASTLINE...WHERE
MAINLY SNOW WILL FALL...AND A TIMES AT FAST CLIP RATES UP TO AN
INCH+ PER HOUR WITHIN THE NEARLY ISOTHERMAL LAYER.
WILL CONTINUE WINTER WEATHER ADVISORIES FOR THE COASTLINE (YORK
COUNTY NORTHWARD) AND WINTER STORM WARNINGS ADJACENT TO THESE
COUNTIES. THESE HEADLINES MAY NEED TO BE TWEAKED DURING THE DAY.
WILL ALSO CONTINUE TO HAVE WINTER WEATHER ADVISORIES IN THE NORTH
AND MOUNTAINS WHICH SHOULD PICK UP 3-6 INCHES OF NEW SNOW. HAVE
INCLUDED NORTHERN COOS COUNTY INTO THE ADVISORIES FOR EASTERN
PORTIONS OF THE COUNTY. WESTERN PORTIONS LIKELY TO HAVE
DOWNSLOPE CONDITIONS DURING THIS EVENT. WAS CONSIDERING EXPANDING
THE WINTER WEATHER ADVISORIES TO INCLUDE NORTHERNMOST PORTIONS OF
INTERIOR ROCKINGHAM COUNTY...BUT WILL OMIT FOR NOW AND LET THE DAY
SHIFT FURTHER EVALUATE.
WITH LITTLE OR NO WRAP AROUND PRECIPITATION WITH THIS SYSTEM...THE
PRECIPITATION QUICKLY COMES TO A HALT AROUND OR SHORTLY AFTER
MIDNIGHT.
ON MONDAY...ARCTIC AIR POURS INTO THE REGION ON GUSTY WINDS
FOLLOWING THE DEPARTING SURFACE LOW. THERE MAY BE A SQUALL OR TWO
IN THE MOUNTAINS WITH THIS SHARP BOUNDARY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
THE LATEST AVAILABLE NUMERICALS ARE IN GOOD AGREEMENT ON LONGWAVE
PATTERN THROUGH LATE NEXT WEEK. IT WILL BE TURNING COLDER WITH
WELL BELOW NORMAL TEMPERATURES FOR MUCH OF THE PERIOD...AS THE
POLAR VORTEX INITIALLY CENTERED NORTH OF HUDSON BAY SETTLES SLOWLY
SOUTHEAST INTO QUEBEC PROVINCE. WE BEGIN THE PERIOD WITH A WEAK
IMPULSE AND ASSOCIATED SURFACE LOW CROSSING THE AREA LATE TUESDAY...
ACCOMPANIED BY A FEW CLOUDS AND SNOW SHOWERS. HIGH PRESSURE AND A
REINFORCING SHOT OF ARCTIC AIR FOLLOWS FOR MIDWEEK. THE NEXT
IMPULSE BRINGS A STRENGTHENING SURFACE LOW JUST TO OUR SOUTH
THURSDAY NIGHT INTO FRIDAY WITH ECMWF AND GFS OFFERING SOME
DIFFERENCES IN BOTH TIMING AND INTENSITY...WITH BOTH SUPPORTING AT
LEAST A MODERATE SNOWFALL TO THE REGION. ANOTHER AREA OF HIGH
PRESSURE FOLLOWS FOR FRIDAY NIGHT AND SATURDAY.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...AREAS OF LIFR CONDITIONS EARLY THIS MORNING IN LOW
CLOUDS AND FOG. CONDITIONS IMPROVING DURING THE MORNING...HOWEVER
CIGS/VSBYS LOWERING ONCE AGAIN TO IFR AND LIFR IN MIXED RAIN AND
SNOW LATE TODAY AND TONIGHT. VFR CONDITIONS EXPECTED ON MONDAY.
LONG TERM...
TUE PM - WED AM...SCT MVFR IN SNOW SHOWERS.
WESTERLY SFC WND GUSTING TO 25 KT.
THU NIGHT - FRI...MVFR WITH AREAS OF IFR IN SNOW.
GUSTY SFC WND TO 25 KT POSSIBLE NR COAST.
&&
.MARINE...
SHORT TERM...HAVE ISSUED GALE WARNINGS FOR THE OUTER WATERS AS THE
NEXT COASTAL LOW INTENSIFIES AND APPROACHES FROM THE SOUTH. SCAS
ISSUED FOR THE BAYS.
LONG TERM...
TUE...SMALL CRAFT CONDITIONS ARE LIKELY.
WED - THU...GALE FORCE WINDS ARE LIKELY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 6 AM EST
MONDAY FOR MEZ012>014-018>022-028.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST
MONDAY FOR MEZ007>009-023>027.
NH...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 6 AM EST
MONDAY FOR NHZ004>006-008>010.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST
MONDAY FOR NHZ001>003.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST
MONDAY FOR NHZ007-013.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM EST MONDAY
FOR ANZ151-153.
GALE WARNING FROM 6 PM THIS EVENING TO 6 PM EST MONDAY FOR
ANZ150-152-154.
&&
$$
NEAR TERM UPDATE... KIMBLE
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
950 PM EST MON DEC 30 2013
.SYNOPSIS...
WEAK LOW PRESSURE MOVES EAST ACROSS THE CAROLINAS TONIGHT...THEN
PUSHES OFFSHORE TUESDAY MORNING. HIGH PRESSURE BUILDS BACK OVER
THE AREA TUESDAY AFTERNOON THROUGH WEDNESDAY. LOW PRESSURE MOVES
THROUGH THE OHIO AND TENNESSEE VALLEYS WEDNESDAY NIGHT AND
THURSDAY...BEFORE CROSSING THE REGION THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
QUICK LOOK AT THE 00Z NAM / HRRR AND 21Z SREF ALL SUGGEST PCPN WILL
HAVE A TUFF TIME GETTING TO FAR NORTH OVERNIGHT AS THE WEAK S/W
MOVES EAST ACROSS THE CAROLINAS. IN ADDITION...2M TEMPS SUGGEST
READINGS HOVER JUST ABOVE FREEZING OVER MOST OF SRN VA/NE NC. SO
MADE SOME ADDITIONAL CHANGES TO OVERNIGHT GRIDS BASED ON THE LATEST
DATA. KEPT A NARROW BAND OF A RAIN/SNOW SHOWER MIX ON NORTHERN
FRINGES OF THE PCPN SHIELD (FVX-PTB-JGG-MVF LINE) WITH JUST RAIN
OVER SOUTHERN / SERN VA AND NE NC COUNTIES. BUMPED UP POPS A BIT
ACROSS THE SOUTHERN AREAS TO 30% WITH .01 QPF AT THE MOST. CAA
ACROSS NRN MOST COUNTIES WILL ALLOW TEMPS TO DROP INTO THE U20S BY
12Z...RANGING INTO THE L-M30S SOUTHERN HALF OF FA.
PVS DSCN:
RAPIDLY DECREASING CLOUDS EXPECTED TUESDAY BEHIND SHORTWAVE WILL
ALLOW FOR A SUNNY/MOSTLY SUNNY DAY...AS HIGH PRESSURE BUILDS INTO
THE AREA. MAX TEMPS WILL BE SLIGHTLY COOLER THAN TODAY. HIGH TEMPS
IN THE MID TO UPR 40S NORTH...LOWER 50S NE NC/ EXTREME SRN VA.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
MOSTLY CLR AND SEASONABLY COLD TUESDAY NIGHT...WITH MIN TEMPS MOSTLY
IN THE 20S. SUNNY/MOSTLY SUNNY WEDNESDAY...WITH MAX TEMPS MID 40S
FAR NORTH...LOWER 50S SOUTH THIRD.
HIGH PRESSURE MOVES OFFSHORE WEDNESDAY NIGHT/THU...AS COMPLEX LOW
PRESSURE BEGINS DEVELOPING ACROSS MS VLY. THIS SYSTEM CONTINUES
ORGANIZING...AND MOVING ENEWD TOWARD THE REGION THU. GFS/ECMWF NOW
SUGGEST MORE WIDESPREAD PRECIP ACROSS THE AREA THU AFTERNOON...
CONTINUING INTO THU NIGHT. NAM MUCH DRIER/WEAKER WITH THIS
SYSTEM...AS IT DELAYS ANY SIFNIFICANT DEEPENING OF THE LOW UNTIL
AFTER 00Z FRIDAY. TEMPS ON THURSDAY IN THE 40S NORTH HALF TO THE
50-55 RANGE SE WILL KEEP ALL PRECIP LIQUID THROUGH 00Z FRI.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE LONG TERM PERIOD BEGINS THURSDAY EVENING WITH A COMPLEX LOW
PRESSURE SYSTEM IN VICINITY OF THE MID ATLANTIC STATES. MODELS ARE
BEGINNING TO CONVERGE ON A SOLUTION WHICH HAS THE MAIN LOW PRESSURE
DEVELOPING OVER THE TENNESSEE VALLEY AND MOVING THROUGH THE
CAROLINAS. THIS WOULD BRING THE POTENTIAL FOR WIDESPREAD PCPN
ACROSS THE AREA ON THURSDAY NIGHT. KEPT POPS IN THE CHC RANGE FOR
NOW UNTIL MODELS BECOME MORE CONSISTENT.
AFTER ABOVE NORMAL TEMPERATURES THURSDAY...TEMPERATURES FALL ON
THURSDAY NIGHT...WHICH WOULD CHANGE PCPN FROM RAIN TO SNOW FROM
NORTH TO SOUTH. PCPN MAY CHANGE TO ALL SNOW BY SHORTLY AFTER
MIDNIGHT N OF A LINE FROM EMPORIA TO WAKEFIELD TO WALLOPS ISLAND. BY
THAT TIME...DRYING MAY END OR DIMINISH PCPN ACROSS SOUTHERN AND
WESTERN PORTIONS OF THE AREA. IT APPEARS THAT THE GREATEST POTENTIAL
FOR ACCUMULATING SNOWFALL WILL BE ON THE LOWER MD EASTERN SHORE.
PCPN SHOULD END FROM W TO E EARLY FRIDAY BUT MAY CONTINUE INTO THE
AFTN ON THE EASTERN SHORE. IT IS TOO EARLY TO SPECULATE ON
ADDITIONAL DETAILS THIS FAR OUT.
THE LOW PRESSURE SYSTEM MOVES QUICKLY OUT TO SEA ON FRIDAY AND
INTENSIFIES RAPIDLY (BOMBS) SOUTHEAST OF NEW ENGLAND. THIS WILL
DRIVE ARCTIC AIR INTO THE AREA LATE FRIDAY AND FRIDAY NIGHT.
TEMPERATURES SATURDAY MORNING ON THE LOWER EASTERN SHORE AND
NORTHERN PORTIONS OF CENTRAL VIRGINIA MAY DROP INTO THE MID TO UPR
TEENS... ESPECIALLY WHERE THERE IS SNOW COVER.
HIGH PRESSURE SETTLES OVER THE AREA SATURDAY BEFORE MOVING OFF TO
THE EAST. TEMPERATURES GO BACK TO ABOVE NORMAL LEVELS BY SUNDAY
AHEAD OF THE NEXT COLD FRONT WHICH IS CURRENTLY PROGGED TO MOVE
THROUGH EARLY MONDAY WITH A CHC FOR SCATTERED SHOWERS. TEMPERATURES
DROP ONCE AGAIN EARLY NEXT WEEK AS A STRONG ARCTIC HIGH PRESSURE
OVER THE PLAINS STATES BEGINS TO BUILD TOWARD THE MID ATLANTIC
STATES.
HIGH TEMPERATURES MAINLY IN THE 30S FRIDAY AND SATURDAY WARM TO THE
UPR 40S NORTH TO 50S SOUTH SUNDAY AND MAINLY 50S MONDAY. LOWS FRIDAY
MORNING MID 20S TO LWR 30S LOWER TO MID TEENS TO LWR 20S SATURDAY
MORNING AND BY MONDAY MORNING IN THE 40S.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
VFR CONDS CONT TO PREVAIL AT THE TAF SITES ALTHOUGH WITH CIGS
AROUND 035-060 FT. WINDS ARE MOSTLY N-NE LESS THAN 10 KT. A WEAK
DISTURBANCE WILL MOVE NE ALONG A STRNY FRONT ACROSS NC TOWARDS
THE SE VA COAST TONIGHT. THIS SYS IS EXPECTED TO PRODUCE SOME
-RA AND PSBL MVFR CIGS FOR ECG AND ORF DURING THE OVERNIGHT. THE
SYS WILL CLEAR THE COAST BY SUNRISE AND CONDS SKIES WILL BECOME
MOSTLY CLR BY MID TO LATE MORNING.
HIGH PRESSURE BUILDS BACK IN LATE TUESDAY AND WEDNESDAY. THE NEXT
WEATHER SYSTEM AFFECTS THE AREA LATE THURSDAY INTO FRIDAY. AREAS OF
RAIN...POSSIBLY TURNING TO LIGHT SNOW THURSDAY NIGHT BEFORE ENDING.
THERE IS UNCERTAINTY IN THE DETAILS BUT FOR NOW HAVE A CHC FOR SNOW
FRIDAY AT SBY. PERIODS OF MVFR/IFR CAN BE EXPECTED DURING THIS
PERIOD.
ARCTIC HIGH PRESSURE BUILDS INTO THE REGION LATE FRIDAY AND SATURDAY
WITH MAINLY CLEAR SKIES.
&&
.MARINE...
CDFNT POISED TO BE S AND E OF THE WTRS THIS EVE. INCRSD WINDSPEEDS
FM THE NNW MAKING THEIR WAY DN FM THE NRN PORTION OF THE
BAY...WHERE AT LEAST GUSTS TO LO END SCA HAVE BEEN NOTED. WILL
GIVE IT SOME TIME FOR SPEEDS TO INCRS HERE AS SFC HI PRES BEHIND
THE FNT MOVES BY JUST N OF THE WTRS THROUGH THIS EVE/ERY OVRNGT
PDS. WILL HOLD ONTO SCAS FOR THE BAY/LWR JAMES RVR BEFORE/THROUGH
MDNGT. LO LVL CAA WANES AFT MDNGT. SFC HI PRES WEAKENS OVR THE NE
CONUS BY TUE AFTN...RESULTING IN WNDS BECOMING MSTLY W. A SECOND
SURGE IN SPEEDS (SHORTLIVED) XPCD LT TUE AFTN/EVE BUT WILL KEEP
CONDS BLO SCA FOR NOW.
SFC HI PRES SLIDES ACRS THE WTRS WED...THEN OFFSHORE BY WED
NGT...W/ WNDS BECOMING MSTLY S (SPDS STAYING BLO 15 KT). MODEL
UNCERTAINTY AFFECTS THE CONFIDENCE OF THE FORECAST LT IN THE WK.
ANOTHER COASTAL STORM APPEARS TO IMPACT THE WATERS IN THE THURS-
FRI MORNING TIMEFRAME. 12Z/30 GFS/ECMWF BOTH DVLPG SGFNT CSTL LO
PRES E OF THE DELMARVA BY FRI MRNG. WILL HOLD OFF ON STRONG CAA
(AND SHARP INCRS IN WINDSPEEDS AND SEA/WAVE HGTS) POST STORM DVLPG
DURG FRI (PSBL GALES?)...WHICH WANES OVR THE WKND.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MPR
NEAR TERM...MPR
SHORT TERM...WRS
LONG TERM...LSA
AVIATION...JEF/LSA
MARINE...ALB
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
549 PM EST SUN DEC 29 2013
.SYNOPSIS...
TONIGHTS COLD FRONT PASSAGE WILL USHER IN BELOW AVERAGE TEMPERATURES
FOR THE COMING WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
EARLY EVE UPDATE WAS ISSUED TO ADJUST HOURLY TEMP AND WEA TRENDS
BASED ON OBS AND THE LATEST HRRR AND RAP MDL TRENDS.
PREVIOUS...
LOW PRES WL CONT TO MOVE OFF THE MID-ATLANTIC COAST THIS
EVE...ENDING THE STEADY RAIN. 850MB TEMPS HAVE COOLED ESP WELL N
OF PIT...AND SOME SNW COULD BRIEFLY MIX IN BEFORE THE PCPN ENDS.
COULD SEE A PD OF DRIZZLE OR LGT RAIN THIS EVE AS DEEP MOISTURE
EXITS.
A CDFNT WL MOVE THRU THE GT LKS/OH VLY RNG OVRNGT. THIS SHOULD
ALLOW FOR ENOUGH MOISTURE IN THE SNOW GROWTH RGN FOR ANY DRIZZLE
TO CHG TO SNW SHWRS AS THE FNT PASSES...PRECLUDING ANY MENTION OF
FREEZING DRIZZLE AS TEMPS FALL. SHOULD SEE UPSLOPE AND LK ENHANCED
SNW SHWRS DVLP AFT FROPA...BUT WITH LMTD MOISTURE DEPTH AND LWRG
TEMP INVERSIONS...SGFNT SNW ACCUMS ARE NOT EXPD. ANY SNW SHWRS ARE
EXPD TO GRDLY END MON AS LLVL RIDGING BLDS IN. TEMPS WL DROP IN
COLD AIR ADVCTN LTR TNGT...WITH LTL RECOVERY ON MON.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
A SHRTWV TROF WILL CROSS THE GRTLKS MON NGT. LOW- TO MID-LVL SWLY
FLOW WILL PROVIDE MODEST WARM AIR AND MSTR ADVCTN...LEADING TO A
BRIEF PD OF DP SATURATION THRU THE DENDRITIC GROWTH LYR. THUS... A
QUICK SHOT OF LGT SNOW WILL BE PSBL LATE MON NGT-TUE MRNG AS THIS
WAVE CROSSES THE RGN. BEST CHCS WILL BE ACRS THE NRN TWO-THIRDS OF
THE FCST AREA.
SGFNT RDG NOT XPCD BEHIND THIS WAVE AS A MORE POTENT AND BROAD
TROF DVLPS IN THE CNTRL CONUS. AS SFC LOPRES STRENGTHENS IN THE
MIDWESTERN STATES...FRONTOGENESIS XPCD TO OCCUR ALONG THE SRN
GRTLKS INTO WRN PA. WARM AIR ADVCTN AND FRONTOGENESIS SHOULD BE
SUFFICIENT TO SUPPORT A BAND OF SNOW FROM PBZ FCST AREA WWD. ANY
ACCUMS ON WED WILL BE LGT OWING TO LOW-LVL DRY AIR AND APPARENT
LACK OF DYNAMICAL FORCING FOR ASCENT.
BAND OF SNOW XPCD TO SHARPEN WED NGT WITH APRCH OF SFC LOPRES AND
INCRG FRONTOGENESIS AND UPR JET ARRIVAL CONTRIBUTING TO STRONGER
UPWD MOTION. TEMPS WED NGT SHOULD SUPPORT SNOW. KRAMAR
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
A COUPLE CHGS WERE MADE TO THE EXTENDED ON THU AND FRI. ON THU...
SFC LOPRES XPCD TO PASS ACRS SRN PORTION OF FCST AREA...WITH
STRONG FRONTOGENESIS XPCD ALONG ARCTIC AMS BNDRY. IN COMBINATION
WITH APRCHG H5 TROF...SUFFICIENT LIFT AND DP SATURATION LKLY WILL
YIELD SNOW OR RAIN/SNOW MIX FOR MOST OF THE FCST AREA. EXACT
TIMING IS UNCERTAIN ATTM...BUT AN INCR IN POPS WAS WARRANTED.
ARCTIC AMS WILL INVADE MUCH OF FCST AREA BY THU NGT. WITH FCSTD H9
TEMPS OF 15-20C BLW ZERO IN BOTH GFS AND ECMWF AND SUPPORTED BY
NAEFS...IT IS VERY DIFFICULT TO SEE HOW MAXIMA WILL RISE OUT OF
THE TEENS. MAXIMA WERE LWRD ON FRI TO REFLECT THIS FCST. PREV
DISCUSSION FOLLOWS... KRAMAR
STILL LOTS TO BE WORKED OUT WITH MODEL SOLUTIONS CONCERNING AN
OVERRUNNING SETUP BY THE MIDDLE OF NEXT WEEK. TEMPS WILL REMAIN
BELOW NORMAL THROUGH THE PERIOD...WITH THE COLDEST AIR EXPECTED BY
THE END OF THE LONG TERM.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
LOW PRES MOVG ACRS THE MD ATLANTIC WL BRING MVFR TO IFR CONDS IN
RAIN THRU ERLY EVE. THE RAIN WL TAPER OFF LT THIS AFTN BUT MVFR
CIGS ARE EXPD TO REMAIN. A CDFNT WL CROSS THE RGN TNGT WITH A FEW
SNW SHWRS AND MVFR CONDS CONTG. LGT WNDS WL SHIFT TO THE W LT THIS
AFTN AS THE SFC LOW PASSES TO OUR E.
.OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
PERIODIC RSTRNS ARE EXPD THRU LT WK AS SVRL DISTURBANCES CROSS THE
RGN.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
15
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
907 PM EST MON DEC 30 2013
.UPDATE...
ISSUED AT 905 PM EST MON DEC 30 2013
HEAVY LES BAND STILL APPEARS TO BE IMPACTING THE N 1/3 OF HOUGHTON
COUNTY AND FAR SOUTHERN KEWEENAW COUNTY. ISSUED A SPECIAL WX
STATEMENT FOR SOME MDT SN TOTALS OVER SRN KEWEENAW COUNTY.
CONSIDERED AN ADVY BASED ON RECENT REPORT OF SN ACCUMULATING AN
INCH/HR AT MOHAWK...BUT SUSPECT THE RESIDENCE TIME OF THE HEAVIER SN
THERE WL BE MORE LIMITED AS THE LLVL WINDS ARE FCST TO VEER MORE TO
THE NW LATER THIS EVNG. IN HOUGHTON COUNTY...THE HEAVY SN SHOULD
GRDLY SHIFT TO THE S AS THE LLVL FLOW VEERS.
ALSO EXPANDED THE WIND CHILL ADVY INTO MENOMINEE/DELTA COUNTIES
GIVEN EXPECTATION FOR CLRG/LOWER MIN TEMPS THERE FOLLOWING DEPARTURE
OF MID CLDS ASSOCIATED WITH DISTURBANCE PASSING TO THE S. LLVL WINDS
ARE FCST TO INCRS LATER TNGT WITH THE STRONGER CAD BEHIND THIS SYS.
ANY INCRS IN MIXING WL BE COUNTERED BY STRONGER ADVECTION OF THE
BITTERLY COLD AIRMASS UPSTREAM...WHERE TEMPS HAVE ALREADY FALLEN AOB
-30F AT SOME PLACES IN NRN MN.
OVER THE E...LES BANDS ARE STILL OFFSHORE. LATEST HI RES MODEL
GUIDANCE STILL SHOWS THESE BANDS COMING ONSHORE TOWARD LATE EVNG FM
GRAND MARAIS TO CRISP POINT...SO MAINTAINED GOING HEADLINES IN THIS
AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 430 PM EST MON DEC 30 2013
MOST OF UPPER MICHIGAN IS QUIET BUT COLD THIS AFTERNOON...AS THE
AREA IS UNDER LINGERING AFFECTS OF THE HIGH PRESSURE RIDGE THAT
MOVED THROUGH LAST NIGHT INTO THIS MORNING. THIS HAS LED TO WINDS
BACKING TO THE WEST-SOUTHWEST IN THE BOUNDARY LAYER AND FOCUSED THE
REMAINING LAKE EFFECT OVER THE KEWEENAW AND RIGHT ALONG THE
SHORELINE NEAR GRAND MARAIS. CALLS TO THE KEWEENAW THIS AFTERNOON
INDICATE THAT THE FINE FLAKE LES IS STILL IN PLACE. WHILE THIS IS
GOOD AT REDUCING VISIBILITIES...ACCUMULATIONS HAVE BEEN LIGHT AND
UNDER A COUPLE INCHES. OVER THE WEST...TEMPERATURES HAVE STRUGGLE
TO EVEN REACH ZERO DEGREES THIS AFTERNOON...WHICH WILL PAVE THE WAY
FOR ANOTHER NIGHT WILL COLD WIND CHILLS. FARTHER TO THE
SOUTHWEST...A SHORTWAVE IS SLIDING EAST-SOUTHEAST THROUGH MINNESOTA
AT THIS TIME AND IS LEADING TO LIGHT SNOW SHOWERS. THESE -SHSN
SHOULD MISS MUCH OF THE AREA...BUT COULD LEAD TO A FEW FLURRIES
ALONG THE WISCONSIN BORDER.
A WEAK SURFACE TROUGH OVER CENTRAL/SOUTHERN LAKE SUPERIOR AT THIS
TIME WILL BE THE FOCUS FOR THE LAKE EFFECT TONIGHT INTO TUESDAY
MORNING. ALL THE HIGH RESOLUTION MODELS SHOW A MESO-LOW DEVELOPING
OVER THE SOUTHEASTERN LAKE THIS EVENING. A LOOK AT THE MONTREAL
RIVER RADAR THIS AFTERNOON DOESN/T INDICATE ANY CIRCULATION AT THIS
POINT...BUT IT SHOULD BE DEVELOPING THIS EVENING. IN ADDITION...THE
LAKE EFFECT SNOW WILL BE ENHANCED BY A SHORTWAVE MOVING THROUGH THIS
EVENING. THIS WAVE PROVIDES A LITTLE MORE MOISTURE AND MID LEVEL
UPWARD MOTION...ALONG WITH COOLING ALOFT TO WEAKEN THE INVERSION
CURRENTLY AROUND 6-8KFT AND ALLOWS IT TO RISE TO 10-12KFT OVER THE
EASTERN CWA. ALSO...IT HELPS INTENSIFY THE SURFACE TROUGH OR
MESO-LOW OVER THE EASTERN LAKE BEFORE IT SLIDES SOUTHEAST LATE
TONIGHT INTO TUESDAY MORNING (BUT STILL LEAVES A TROUGH OVER THE
EASTERN LAKE). SINCE THIS HAS BEEN SHOWN FOR SEVERAL DAYS
NOW...FAIRLY CONFIDENT ON ITS OCCURRENCE...THE QUESTION COMES DOWN
TO EXACT LOCATION OF THE HEAVIEST BAND AND WHAT THE SNOW RATIOS WILL
BE. LATEST TRENDS IN THE MODELS SHOW A SLIGHTLY LATER ARRIVAL OF
THE STRONG LES BAND ON THE WEST SIDE OF THE MESO-LOW...LIKELY
CLOSER TO 04-06Z. UNFORTUNATELY THE LOCATION IS ALL OVER
THE MAP...WITH SOME HAVE IT HITTING PICTURED ROCKS (AND
NEARLY MUNISING - RAP AND A COUPLE 15Z HOPWRF MEMBERS) WHILE OTHERS
THE FAR NORTHEAST PART OF LUCE COUNTY (2.5 AND 10KM REGIONAL GEMS).
OPTED TO FOCUS ON THE MIDDLE GROUND WHICH WAS SIMILAR TO THE
PREVIOUS FORECAST AND HAVE THE STRONG BAND COME ONSHORE AROUND THE
GRAND MARAIS AREA. PINNING DOWN THIS LOCATION WILL MAKE OR BREAK
SNOWFALL AMOUNTS AND THE POTENTIAL OF REACHING WARNING SNOWFALL
AMOUNTS. ONCE THIS BAND COMES ON SHORE EXPECT A TRANSITION TO A
GENERAL NORTHWEST FLOW LES THROUGH THE DAY ON TUESDAY. WITH A
WEAK SURFACE TROUGH LINGERING OVER THE FAR EASTERN LAKE...MODELS
ARE INDICATING SOME ENHANCED CONVERGENCE TO LEAD TO A STRONGER BAND
AFFECTING NORTHERN LUCE COUNTY...ALTHOUGH THERE WILL BE SOME
WAVERING EXPECTED.
AS FOR SNOW RATIOS AND AMOUNTS...ARCTIC AIR MASS WILL LIKELY BE
MODIFIED SOMEWHAT FROM THE CIRCULATION AND MOISTURE/HEAT FLUX OFF
THE LAKE...WHICH WILL TRY TO PUT SOME OF THE CLOUD INTO THE DGZ.
THUS...WOULD EXPECT SOME HIGHER RATIOS TONIGHT AS THE BAND
COMES ON SHORE AND BEFORE SLIGHTLY COOLER AIR ARRIVES ON
TUESDAY AND TRANSITION BACK TO MORE OF A FINER FLAKE SNOW THAT
WE HAVE SEEN THE LAST 24-48HRS. ON TO AMOUNTS...PREVIOUS FORECAST
WAS RIGHT ON THE EDGE OF BOTH 12/24HR AMOUNTS AND HAVE SIMILAR IF
NOT SLIGHTLY LOWER VALUES FOR THIS FORECAST. THINK THERE WILL BE A
GOOD BURST WITH THAT STRONG BAND TONIGHT INTO TUESDAY MORNING OF 3
TO 7 INCHES. THEN THE TRANSITION TO MORE NORTHWEST WINDS AND
SLIGHTLY LOWER RATIOS SHOULD LEAD TO ANOTHER PERIOD OF 2-6 INCHES
FROM MID MORNING INTO THE EARLY EVENING (BUT LIKELY FOCUSED FARTHER
EAST INTO LUCE COUNTY). THIS IS JUST PUTS THE FORECAST JUST UNDER
BOTH THE 12/24HR WARNING AMOUNTS AND WITH THE UNCERTAINTY IN THE
EXACT LOCATION OF THE HEAVIEST SNOW...WILL ISSUE A STRONGLY WORDED
ADVISORY FOR ALGER/LUCE AND NORTHERN SCHOOLCRAFT FOR TONIGHT INTO
TUESDAY. THAT WAY WE CAN HOPEFULLY GET ONE MORE LOOK AT HIGH RES
RUNS AND IF THERE IS A BETTER HANDLE ON LOCATION AND CONFIDENCE
GROWS ON WARNING AMOUNTS...CAN UPGRADE THIS EVENING OR TONIGHT FOR
THE MORE SPECIFIC LOCATION. WITH ALL OF THE LOCATION
DIFFERENCES...WOULD HATE TO ISSUE A WARNING FOR LUCE AND THEN HAVE
IT STAY MAINLY IN ALGER OR VICE-VERSA.
OVER THE WEST...A SURFACE TROUGH STRETCHED WEST ACROSS SOUTHERN
LAKE SUPERIOR WILL SLOWLY PUSH THE MAIN BAND AFFECTING THE KEWEENAW
SOUTH TONIGHT INTO THE ONTONAGON AND SOUTHERN PORTIONS OF HOUGHTON
COUNTY AREA TONIGHT. AS THIS OCCURS...THE REST OF THE KEWEENAW WILL
TRANSITION TO MORE OF A NW FLOW LAKE EFFECT SCENARIO WHICH WILL
CONTINUE INTO TUESDAY. LESS RESIDENCE TIME OVER WESTERN LAKE
SUPERIOR WILL LIMIT THE ARCTIC AIR MASS MODERATION AND SHOULD KEEP
MOST OF THE CLOUD LAYER ABOVE THE DGZ. THUS...WOULD EXPECT THE
SMALLER SNOW FLAKES AND RATIOS TO CONTINUE THERE AND LIMIT
ACCUMULATIONS. INVERSION HEIGHTS ARE GREATER THAN THE PAST 24HRS
(7-9KFT) WHICH WILL LEAD TO SLIGHTLY STRONGER SHOWERS...BUT ALL OF
THAT CLOUD LAYER WILL BE WELL ABOVE THE DGZ. CURRENT THOUGHT IS
THERE BEING AN INCREASE IN SNOW ACCUMULATION THIS EVENING...BEFORE
COLDER 850MB TEMPS MOVE IN BEHIND THE SHORTWAVE (FALLING TO ALMOST
-26C BY 12Z TUESDAY) AND PUSH ALL OF THE CLOUD ABOVE THE DGZ.
ALTHOUGH TOTAL AMOUNTS OVER THE 24 HOUR PERIOD MAY REACH THE 3-6INCH
RANGE...THINK 12HR AMOUNTS WILL BE HARD PRESSED TO REACH THE 4 INCH
AMOUNT NEEDED FOR A LES ADVISORY.
A COLD START TO THE DAY AND A TIGHTENING SURFACE GRADIENT WITH THE
SURFACE DROPPING SOUTH INTO NORTHERN UPPER MICHIGAN TONIGHT WILL
LEAD TO ANOTHER NIGHT OF VERY COLD WIND CHILLS. THINK THE SCATTERED
HIGH CLOUDS AND SLIGHTLY HIGHER WINDS WILL KEEP TEMPS SLIGHTLY
WARMER THAN LAST NIGHT. BUT THIS WILL ALSO KEEP WIND CHILLS LOW AND
SIMILAR TO LAST NIGHT. THEREFORE...HAVE ISSUED A WIND CHILL
ADVISORY FOR THE SAME LOCATIONS AS LAST NIGHT AND HAVE IT RUNNING
THROUGH LATE TUESDAY MORNING. ONCE AGAIN...TEMPERATURES WILL
STRUGGLE TO REBOUND TOMORROW AND SOME LOCATIONS OUT WEST WILL STAY
IN THE SINGLE DIGITS BELOW ZERO.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 430 PM EST MON DEC 30 2013
MODELS ARE CONSISTENT IN SHOWING THE 500MB CLOSED LOW OVER QUEBEC
WEDNESDAY MOVING OFF INTO THE ATLANTIC THURSDAY. THE GFS /AS USUAL/
IS MORE PROGRESSIVE THAN THE ECWMF WITH THE LONGWAVE TROUGH IN THE
WAKE OF THE LOW...BRINGING THE TROUGH THROUGH THE GREAT LAKES ON
THURSDAY AFTERNOON. THE ECMWF IS SLOWER AND DEEPER WITH THIS
TROUGH...WITH IT BEING MAINLY OVER WI ON THURSDAY AFTERNOON.
GUIDANCE SUGGESTS THAT THE ECMWF HAS BEEN ERRING ON THE DEEPER AND
MORE AMPLIFIED SIDE LATELY...HOWEVER...AND THIS MAY BE THE CASE.
OVERALL WENT MIDDLE OF THE ROAD FOR THE FORECAST AT THIS
POINT...LEANING MORE TOWARDS THE ECMWF. AS FAR AS WHAT THIS MEANS
FOR THE SURFACE...LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS AND
RIDES NORTHEASTWARD ALONG THE TROUGH...WHICH BRINGS AN INVERTED
SURFACE TROUGH INTO UPPER MI FOR WEDNESDAY NIGHT-THURSDAY AFTERNOON.
TUESDAY NIGHT WINDS REMAIN OUT OF THE WEST NORTHWEST THROUGH
MIDNIGHT...BEFORE GRADUALLY VEERING TO THE NORTH AND EVEN NORTHEAST
AS THE INVERTED TROUGH SHIFTS WESTWARD. THIS MOVES THE HIGHEST POPS
FROM THE FAR NORTHEASTERN PORTIONS OF THE COUNTY TOWARDS MUNISING
THROUGH THE NIGHT. BY WEDNESDAY AFTERNOON...CONVERGENCE FOCUSES
BETWEEN MARQUETTE AND MUNISING...WHICH IS WHERE HIGHEST POPS ARE
SITUATED IN THE GRIDS. WHILE THIS REMAINS THE CASE THROUGH THURSDAY
AFTERNOON...TOTAL ACCUMULATIONS ARE GENERALLY EXPECTED TO BE ON THE
ORDER OF 2 TO 4 INCHES BETWEEN SHOT POINT AND MUNISING. GIVEN THAT
MOST OF THE BANDS ARE SHIFTING FROM WEST-NORTHWEST INTO A MORE
NORTH-NORTHEAST PATTERN THROUGH THE PERIOD...NOT REALLY EXPECTING
ANY ONE LOCATION TO RECEIVE TOO MUCH ACCUMULATION. ALSO...BEYOND
WEDNESDAY MORNING...WINDS AT 850-925MB BECOME SOMEWHAT MISALIGNED
WITH THE SURFACE WINDS...WHICH IS TYPICALLY LESS SUITABLE FOR MORE
STRUCTURED BANDS. THOUGH INVERSION HEIGHTS ARE HIGHER WITH COLDER
850MB TEMPS...GENERALLY UP TO 6-8KFT...THE DGZ IS LOW AND SO EXPECT
THE SAME SMALL SIZED FLAKES-AND LOW ACCUMULATIONS LIKE THOSE
OBSERVED ACROSS UPPER MI ALL WEEK/DESPITE SIMILAR INVERSION HEIGHTS.
THE NAM HINTS AT SOME HIGHER SNOW RATIOS OCCURRING IN THE
EAST...HOWEVER...THE NAM HAS BEEN TRENDING HIGHER THROUGH THIS PAST
WEEK THAN WHAT IS BEING OBSERVED. OVERALL...WEVE SEEN AROUND 18-20:1
RATIOS...AND THIS IS WHAT WAS USED FOR THE FORECAST. USING THE
NAM...THE BEST LIFT COLLOCATED WITH THE DGZ IS BETWEEN 6Z AND 15Z
WEDNESDAY AROUND MUNISING...AND SOME BIGGER FLAKES MAY BE SEEN
DURING THIS TIME. OTHERWISE...EXPECT ACCUMULATIONS TO RANGE FROM 1-3
INCHES NEAR THE LAKE FROM 6Z WEDNESDAY TO 12Z THURSDAY.
FRIDAY INTO SATURDAY LOW PRESSURE SLIDING OVER THE CANADIAN PRAIRIE
WILL SWING WINDS AROUND TO THE SOUTH ACROSS UPPER MI...PUSHING ALL
LAKE EFFECT SNOW BANDS OFF INTO LAKE SUPERIOR. 850MB TEMPS WARM AS
WELL...WITH THE ECMWF HINTING AT -8C TO -10C FOR BOTH DAYS. THE COLD
FRONT PASSES ON SATURDAY NIGHT. THE ARCTIC PUSH BEHIND THIS TROUGH
IS NOT TOO BAD...AS TEMPS 850MB TEMPS ARE SOMEWHAT RESCUED BY A
BRIEF RIDGE MOVING FROM THE NORTHERN PLAINS INTO THE GREAT LAKES
THROUGH SUNDAY AFTERNOON. KEPT BROAD CHANCE POPS ACROSS THE CWA FOR
MUCH OF THE FORECAST AREA THROUGH SATURDAY NIGHT. ON SUNDAY...TEMPS
ARE COLD ENOUGH AND WINDS OUT OF THE WEST-NORTHWEST...SO KEPT CHANCE
POPS CONFINED TO LAKE SUPERIOR.
THE MAIN DIFFERENCES BETWEEN MODELS LIE ON MONDAY...WITH THE ECMWF
AND THE GFS BOTH HINTING AT A VERY COLD ARCTIC PUSH OF AIR SLIDING
THROUGH...WITH 850MB TEMPS AS LOW AS -35C OVER UPPER MI. THOUGH THE
GFS IS NOT QUITE AS LOW...IT HAS 850MB TEMPS AT -25C TO -30C FOR THE
AREA. WILL TREND LOWER WITH TEMPS DURING THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 629 PM EST MON DEC 30 2013
KIWD...AS WINDS VEER FM SW TO WNW IN THE WAKE OF A DISTURBANCE
PASSING TO THE S OF UPR MI...EXPECT SOME LK EFFECT CLDS/-SHSN TO
SPREAD BACK OVER THIS SITE OVENGT AND TUE. CONDITIONS WL DETERIORATE
FM VFR TO MVFR AND PERHAPS IFR ON TUE.
KCMX...BAND OF HEAVY LK EFFECT SHSN THAT HAS IMPACTED THIS LOCATION
INTO EARLY THIS EVNG WL SHIFT TO THE S BY LATE EVNG...WITH LIGHTER
MULTIPLE BAND LK EFFECT -SHSN DOMINATING THE REST OF THE FCST PERIOD
AS THE SHARPER BAND OF LLVL CNVGC SHIFTS TO THE S AND GIVES WAY TO A
NW WIND. THE RESULT SHOULD BE SOME LIFR CONDITIONS GIVING WAY TO A
PREDOMINANT IFR VSBY.
SAW...WITH A DOWNSLOPE WSW FLOW OF DRY ARCTIC AIR VEERING TO WNW...
EXPECT VFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD EVEN THOUGH
OCNL FLURRIES/MVFR CIGS WL BE POSSIBLE ON TUE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 430 PM EST MON DEC 30 2013
WEST-NORTHWEST WINDS WILL VEER TO THE NORTHWEST TONIGHT AND BE IN
THE 15-25KT RANGE. THERE COULD BE SOME GUSTS TO 30KTS OVER THE
EASTERN LAKE AS A MESO-LOW DEVELOPS. THESE WINDS WILL CONTINUE TO
PRODUCE SOME AREAS OF HEAVY FREEZING SPRAY AND WILL CONTINUE THE
HEAVY FREEZING SPRAY WARNING INTO WEDNESDAY MORNING OVER THE EAST.
OTHERWISE...LIGHTER WINDS ARE EXPECTED WEDNESDAY AND THURSDAY
BEFORE AN INCREASE OUT OF THE SOUTHWEST ON FRIDAY AND FRIDAY NIGHT.
THERE COULD BE A FEW GALE FORCE GUSTS TO 35KTS WHEN THIS OCCURS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL 11 AM EST /10 AM CST/ TUESDAY FOR
MIZ002-004-005-009>011-084.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST TUESDAY FOR MIZ006-007-
085.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ003.
WIND CHILL ADVISORY FROM 3 AM EST /2 AM CST/ TO 11 AM EST /10 AM
CST/ TUESDAY FOR MIZ012-013.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ266.
HEAVY FREEZING SPRAY WARNING FROM 6 AM TUESDAY TO 4 AM EST
WEDNESDAY FOR LSZ248-265.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST WEDNESDAY FOR LSZ243-
244-264.
HEAVY FREEZING SPRAY WARNING UNTIL 10 PM EST /9 PM CST/ TUESDAY
FOR LSZ241-242-263.
HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST WEDNESDAY FOR LSZ249-
250.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...SRF
LONG TERM...MCD
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
630 PM EST MON DEC 30 2013
.UPDATE...
ISSUED AT 512 PM EST MON DEC 30 2013
DESPITE DRY/STABLE NATURE OF ARCTIC AIRMASS SHOWN ON THE 12Z INL
RAOB AND RELATIVELY POOR SN GROWTH PARAMETERS...ISSUED A LK EFFECT
SN WARNING FOR NRN HOUGHTON COUNTY PER SFC REPORTS OF SN FALL RATES
OVER AN INCH/HR UNDER A HEAVY SN BAND SHOWN ON VSBL STLT IMAGERY
STREAMING FM THE BAYFIELD PENINSULA INTO THE N HALF OF HOUGHTON
COUNTY. THIS BAND APPEARS TO BE FOCUSED IN THE LLVL CNVGC BTWN A MORE
NW FLOW OBSVD AT THE MARINE SITES ON ISLE ROYALE AND WSW LAND BREEZE
FLOW TO THE S WITHIN VERY COLD ARCTIC AIRMASS OVER UPR MI. THE 18Z
CNDN MODEL APPEARS TO HAVE THE BEST HANDLE ON THE LOCATION OF THIS
FEATURE AND INDICATES THE FOCUSED LLVL CNVGC/HEAVY SN BAND WL SHIFT
ONLY SLOWLY S THRU THE NGT BEFORE DIMINISHING TOWARD 12Z. GIVEN OBS
AND POTENTIAL LONGER RESIDENCE TIME OF THE HEAVIER SN...OPTED TO GO
WITH WRNG THRU 12Z TUE AS TWO SPOTTERS IN CALUMET HAVE ALREADY
REPORTED 6 INCHES OF SN BTWN NOON AND 4-5PM.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 430 PM EST MON DEC 30 2013
MOST OF UPPER MICHIGAN IS QUIET BUT COLD THIS AFTERNOON...AS THE
AREA IS UNDER LINGERING AFFECTS OF THE HIGH PRESSURE RIDGE THAT
MOVED THROUGH LAST NIGHT INTO THIS MORNING. THIS HAS LED TO WINDS
BACKING TO THE WEST-SOUTHWEST IN THE BOUNDARY LAYER AND FOCUSED THE
REMAINING LAKE EFFECT OVER THE KEWEENAW AND RIGHT ALONG THE
SHORELINE NEAR GRAND MARAIS. CALLS TO THE KEWEENAW THIS AFTERNOON
INDICATE THAT THE FINE FLAKE LES IS STILL IN PLACE. WHILE THIS IS
GOOD AT REDUCING VISIBILITIES...ACCUMULATIONS HAVE BEEN LIGHT AND
UNDER A COUPLE INCHES. OVER THE WEST...TEMPERATURES HAVE STRUGGLE
TO EVEN REACH ZERO DEGREES THIS AFTERNOON...WHICH WILL PAVE THE WAY
FOR ANOTHER NIGHT WILL COLD WIND CHILLS. FARTHER TO THE
SOUTHWEST...A SHORTWAVE IS SLIDING EAST-SOUTHEAST THROUGH MINNESOTA
AT THIS TIME AND IS LEADING TO LIGHT SNOW SHOWERS. THESE -SHSN
SHOULD MISS MUCH OF THE AREA...BUT COULD LEAD TO A FEW FLURRIES
ALONG THE WISCONSIN BORDER.
A WEAK SURFACE TROUGH OVER CENTRAL/SOUTHERN LAKE SUPERIOR AT THIS
TIME WILL BE THE FOCUS FOR THE LAKE EFFECT TONIGHT INTO TUESDAY
MORNING. ALL THE HIGH RESOLUTION MODELS SHOW A MESO-LOW DEVELOPING
OVER THE SOUTHEASTERN LAKE THIS EVENING. A LOOK AT THE MONTREAL
RIVER RADAR THIS AFTERNOON DOESN/T INDICATE ANY CIRCULATION AT THIS
POINT...BUT IT SHOULD BE DEVELOPING THIS EVENING. IN ADDITION...THE
LAKE EFFECT SNOW WILL BE ENHANCED BY A SHORTWAVE MOVING THROUGH THIS
EVENING. THIS WAVE PROVIDES A LITTLE MORE MOISTURE AND MID LEVEL
UPWARD MOTION...ALONG WITH COOLING ALOFT TO WEAKEN THE INVERSION
CURRENTLY AROUND 6-8KFT AND ALLOWS IT TO RISE TO 10-12KFT OVER THE
EASTERN CWA. ALSO...IT HELPS INTENSIFY THE SURFACE TROUGH OR
MESO-LOW OVER THE EASTERN LAKE BEFORE IT SLIDES SOUTHEAST LATE
TONIGHT INTO TUESDAY MORNING (BUT STILL LEAVES A TROUGH OVER THE
EASTERN LAKE). SINCE THIS HAS BEEN SHOWN FOR SEVERAL DAYS
NOW...FAIRLY CONFIDENT ON ITS OCCURRENCE...THE QUESTION COMES DOWN
TO EXACT LOCATION OF THE HEAVIEST BAND AND WHAT THE SNOW RATIOS WILL
BE. LATEST TRENDS IN THE MODELS SHOW A SLIGHTLY LATER ARRIVAL OF
THE STRONG LES BAND ON THE WEST SIDE OF THE MESO-LOW...LIKELY
CLOSER TO 04-06Z. UNFORTUNATELY THE LOCATION IS ALL OVER
THE MAP...WITH SOME HAVE IT HITTING PICTURED ROCKS (AND
NEARLY MUNISING - RAP AND A COUPLE 15Z HOPWRF MEMBERS) WHILE OTHERS
THE FAR NORTHEAST PART OF LUCE COUNTY (2.5 AND 10KM REGIONAL GEMS).
OPTED TO FOCUS ON THE MIDDLE GROUND WHICH WAS SIMILAR TO THE
PREVIOUS FORECAST AND HAVE THE STRONG BAND COME ONSHORE AROUND THE
GRAND MARAIS AREA. PINNING DOWN THIS LOCATION WILL MAKE OR BREAK
SNOWFALL AMOUNTS AND THE POTENTIAL OF REACHING WARNING SNOWFALL
AMOUNTS. ONCE THIS BAND COMES ON SHORE EXPECT A TRANSITION TO A
GENERAL NORTHWEST FLOW LES THROUGH THE DAY ON TUESDAY. WITH A
WEAK SURFACE TROUGH LINGERING OVER THE FAR EASTERN LAKE...MODELS
ARE INDICATING SOME ENHANCED CONVERGENCE TO LEAD TO A STRONGER BAND
AFFECTING NORTHERN LUCE COUNTY...ALTHOUGH THERE WILL BE SOME
WAVERING EXPECTED.
AS FOR SNOW RATIOS AND AMOUNTS...ARCTIC AIR MASS WILL LIKELY BE
MODIFIED SOMEWHAT FROM THE CIRCULATION AND MOISTURE/HEAT FLUX OFF
THE LAKE...WHICH WILL TRY TO PUT SOME OF THE CLOUD INTO THE DGZ.
THUS...WOULD EXPECT SOME HIGHER RATIOS TONIGHT AS THE BAND
COMES ON SHORE AND BEFORE SLIGHTLY COOLER AIR ARRIVES ON
TUESDAY AND TRANSITION BACK TO MORE OF A FINER FLAKE SNOW THAT
WE HAVE SEEN THE LAST 24-48HRS. ON TO AMOUNTS...PREVIOUS FORECAST
WAS RIGHT ON THE EDGE OF BOTH 12/24HR AMOUNTS AND HAVE SIMILAR IF
NOT SLIGHTLY LOWER VALUES FOR THIS FORECAST. THINK THERE WILL BE A
GOOD BURST WITH THAT STRONG BAND TONIGHT INTO TUESDAY MORNING OF 3
TO 7 INCHES. THEN THE TRANSITION TO MORE NORTHWEST WINDS AND
SLIGHTLY LOWER RATIOS SHOULD LEAD TO ANOTHER PERIOD OF 2-6 INCHES
FROM MID MORNING INTO THE EARLY EVENING (BUT LIKELY FOCUSED FARTHER
EAST INTO LUCE COUNTY). THIS IS JUST PUTS THE FORECAST JUST UNDER
BOTH THE 12/24HR WARNING AMOUNTS AND WITH THE UNCERTAINTY IN THE
EXACT LOCATION OF THE HEAVIEST SNOW...WILL ISSUE A STRONGLY WORDED
ADVISORY FOR ALGER/LUCE AND NORTHERN SCHOOLCRAFT FOR TONIGHT INTO
TUESDAY. THAT WAY WE CAN HOPEFULLY GET ONE MORE LOOK AT HIGH RES
RUNS AND IF THERE IS A BETTER HANDLE ON LOCATION AND CONFIDENCE
GROWS ON WARNING AMOUNTS...CAN UPGRADE THIS EVENING OR TONIGHT FOR
THE MORE SPECIFIC LOCATION. WITH ALL OF THE LOCATION
DIFFERENCES...WOULD HATE TO ISSUE A WARNING FOR LUCE AND THEN HAVE
IT STAY MAINLY IN ALGER OR VICE-VERSA.
OVER THE WEST...A SURFACE TROUGH STRETCHED WEST ACROSS SOUTHERN
LAKE SUPERIOR WILL SLOWLY PUSH THE MAIN BAND AFFECTING THE KEWEENAW
SOUTH TONIGHT INTO THE ONTONAGON AND SOUTHERN PORTIONS OF HOUGHTON
COUNTY AREA TONIGHT. AS THIS OCCURS...THE REST OF THE KEWEENAW WILL
TRANSITION TO MORE OF A NW FLOW LAKE EFFECT SCENARIO WHICH WILL
CONTINUE INTO TUESDAY. LESS RESIDENCE TIME OVER WESTERN LAKE
SUPERIOR WILL LIMIT THE ARCTIC AIR MASS MODERATION AND SHOULD KEEP
MOST OF THE CLOUD LAYER ABOVE THE DGZ. THUS...WOULD EXPECT THE
SMALLER SNOW FLAKES AND RATIOS TO CONTINUE THERE AND LIMIT
ACCUMULATIONS. INVERSION HEIGHTS ARE GREATER THAN THE PAST 24HRS
(7-9KFT) WHICH WILL LEAD TO SLIGHTLY STRONGER SHOWERS...BUT ALL OF
THAT CLOUD LAYER WILL BE WELL ABOVE THE DGZ. CURRENT THOUGHT IS
THERE BEING AN INCREASE IN SNOW ACCUMULATION THIS EVENING...BEFORE
COLDER 850MB TEMPS MOVE IN BEHIND THE SHORTWAVE (FALLING TO ALMOST
-26C BY 12Z TUESDAY) AND PUSH ALL OF THE CLOUD ABOVE THE DGZ.
ALTHOUGH TOTAL AMOUNTS OVER THE 24 HOUR PERIOD MAY REACH THE 3-6INCH
RANGE...THINK 12HR AMOUNTS WILL BE HARD PRESSED TO REACH THE 4 INCH
AMOUNT NEEDED FOR A LES ADVISORY.
A COLD START TO THE DAY AND A TIGHTENING SURFACE GRADIENT WITH THE
SURFACE DROPPING SOUTH INTO NORTHERN UPPER MICHIGAN TONIGHT WILL
LEAD TO ANOTHER NIGHT OF VERY COLD WIND CHILLS. THINK THE SCATTERED
HIGH CLOUDS AND SLIGHTLY HIGHER WINDS WILL KEEP TEMPS SLIGHTLY
WARMER THAN LAST NIGHT. BUT THIS WILL ALSO KEEP WIND CHILLS LOW AND
SIMILAR TO LAST NIGHT. THEREFORE...HAVE ISSUED A WIND CHILL
ADVISORY FOR THE SAME LOCATIONS AS LAST NIGHT AND HAVE IT RUNNING
THROUGH LATE TUESDAY MORNING. ONCE AGAIN...TEMPERATURES WILL
STRUGGLE TO REBOUND TOMORROW AND SOME LOCATIONS OUT WEST WILL STAY
IN THE SINGLE DIGITS BELOW ZERO.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 430 PM EST MON DEC 30 2013
MODELS ARE CONSISTENT IN SHOWING THE 500MB CLOSED LOW OVER QUEBEC
WEDNESDAY MOVING OFF INTO THE ATLANTIC THURSDAY. THE GFS /AS USUAL/
IS MORE PROGRESSIVE THAN THE ECWMF WITH THE LONGWAVE TROUGH IN THE
WAKE OF THE LOW...BRINGING THE TROUGH THROUGH THE GREAT LAKES ON
THURSDAY AFTERNOON. THE ECMWF IS SLOWER AND DEEPER WITH THIS
TROUGH...WITH IT BEING MAINLY OVER WI ON THURSDAY AFTERNOON.
GUIDANCE SUGGESTS THAT THE ECMWF HAS BEEN ERRING ON THE DEEPER AND
MORE AMPLIFIED SIDE LATELY...HOWEVER...AND THIS MAY BE THE CASE.
OVERALL WENT MIDDLE OF THE ROAD FOR THE FORECAST AT THIS
POINT...LEANING MORE TOWARDS THE ECMWF. AS FAR AS WHAT THIS MEANS
FOR THE SURFACE...LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS AND
RIDES NORTHEASTWARD ALONG THE TROUGH...WHICH BRINGS AN INVERTED
SURFACE TROUGH INTO UPPER MI FOR WEDNESDAY NIGHT-THURSDAY AFTERNOON.
TUESDAY NIGHT WINDS REMAIN OUT OF THE WEST NORTHWEST THROUGH
MIDNIGHT...BEFORE GRADUALLY VEERING TO THE NORTH AND EVEN NORTHEAST
AS THE INVERTED TROUGH SHIFTS WESTWARD. THIS MOVES THE HIGHEST POPS
FROM THE FAR NORTHEASTERN PORTIONS OF THE COUNTY TOWARDS MUNISING
THROUGH THE NIGHT. BY WEDNESDAY AFTERNOON...CONVERGENCE FOCUSES
BETWEEN MARQUETTE AND MUNISING...WHICH IS WHERE HIGHEST POPS ARE
SITUATED IN THE GRIDS. WHILE THIS REMAINS THE CASE THROUGH THURSDAY
AFTERNOON...TOTAL ACCUMULATIONS ARE GENERALLY EXPECTED TO BE ON THE
ORDER OF 2 TO 4 INCHES BETWEEN SHOT POINT AND MUNISING. GIVEN THAT
MOST OF THE BANDS ARE SHIFTING FROM WEST-NORTHWEST INTO A MORE
NORTH-NORTHEAST PATTERN THROUGH THE PERIOD...NOT REALLY EXPECTING
ANY ONE LOCATION TO RECEIVE TOO MUCH ACCUMULATION. ALSO...BEYOND
WEDNESDAY MORNING...WINDS AT 850-925MB BECOME SOMEWHAT MISALIGNED
WITH THE SURFACE WINDS...WHICH IS TYPICALLY LESS SUITABLE FOR MORE
STRUCTURED BANDS. THOUGH INVERSION HEIGHTS ARE HIGHER WITH COLDER
850MB TEMPS...GENERALLY UP TO 6-8KFT...THE DGZ IS LOW AND SO EXPECT
THE SAME SMALL SIZED FLAKES-AND LOW ACCUMULATIONS LIKE THOSE
OBSERVED ACROSS UPPER MI ALL WEEK/DESPITE SIMILAR INVERSION HEIGHTS.
THE NAM HINTS AT SOME HIGHER SNOW RATIOS OCCURRING IN THE
EAST...HOWEVER...THE NAM HAS BEEN TRENDING HIGHER THROUGH THIS PAST
WEEK THAN WHAT IS BEING OBSERVED. OVERALL...WEVE SEEN AROUND 18-20:1
RATIOS...AND THIS IS WHAT WAS USED FOR THE FORECAST. USING THE
NAM...THE BEST LIFT COLLOCATED WITH THE DGZ IS BETWEEN 6Z AND 15Z
WEDNESDAY AROUND MUNISING...AND SOME BIGGER FLAKES MAY BE SEEN
DURING THIS TIME. OTHERWISE...EXPECT ACCUMULATIONS TO RANGE FROM 1-3
INCHES NEAR THE LAKE FROM 6Z WEDNESDAY TO 12Z THURSDAY.
FRIDAY INTO SATURDAY LOW PRESSURE SLIDING OVER THE CANADIAN PRAIRIE
WILL SWING WINDS AROUND TO THE SOUTH ACROSS UPPER MI...PUSHING ALL
LAKE EFFECT SNOW BANDS OFF INTO LAKE SUPERIOR. 850MB TEMPS WARM AS
WELL...WITH THE ECMWF HINTING AT -8C TO -10C FOR BOTH DAYS. THE COLD
FRONT PASSES ON SATURDAY NIGHT. THE ARCTIC PUSH BEHIND THIS TROUGH
IS NOT TOO BAD...AS TEMPS 850MB TEMPS ARE SOMEWHAT RESCUED BY A
BRIEF RIDGE MOVING FROM THE NORTHERN PLAINS INTO THE GREAT LAKES
THROUGH SUNDAY AFTERNOON. KEPT BROAD CHANCE POPS ACROSS THE CWA FOR
MUCH OF THE FORECAST AREA THROUGH SATURDAY NIGHT. ON SUNDAY...TEMPS
ARE COLD ENOUGH AND WINDS OUT OF THE WEST-NORTHWEST...SO KEPT CHANCE
POPS CONFINED TO LAKE SUPERIOR.
THE MAIN DIFFERENCES BETWEEN MODELS LIE ON MONDAY...WITH THE ECMWF
AND THE GFS BOTH HINTING AT A VERY COLD ARCTIC PUSH OF AIR SLIDING
THROUGH...WITH 850MB TEMPS AS LOW AS -35C OVER UPPER MI. THOUGH THE
GFS IS NOT QUITE AS LOW...IT HAS 850MB TEMPS AT -25C TO -30C FOR THE
AREA. WILL TREND LOWER WITH TEMPS DURING THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 629 PM EST MON DEC 30 2013
KIWD...AS WINDS VEER FM SW TO WNW IN THE WAKE OF A DISTURBANCE
PASSING TO THE S OF UPR MI...EXPECT SOME LK EFFECT CLDS/-SHSN TO
SPREAD BACK OVER THIS SITE OVENGT AND TUE. CONDITIONS WL DETERIORATE
FM VFR TO MVFR AND PERHAPS IFR ON TUE.
KCMX...BAND OF HEAVY LK EFFECT SHSN THAT HAS IMPACTED THIS LOCATION
INTO EARLY THIS EVNG WL SHIFT TO THE S BY LATE EVNG...WITH LIGHTER
MULTIPLE BAND LK EFFECT -SHSN DOMINATING THE REST OF THE FCST PERIOD
AS THE SHARPER BAND OF LLVL CNVGC SHIFTS TO THE S AND GIVES WAY TO A
NW WIND. THE RESULT SHOULD BE SOME LIFR CONDITIONS GIVING WAY TO A
PREDOMINANT IFR VSBY.
SAW...WITH A DOWNSLOPE WSW FLOW OF DRY ARCTIC AIR VEERING TO WNW...
EXPECT VFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD EVEN THOUGH
OCNL FLURRIES/MVFR CIGS WL BE POSSIBLE ON TUE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 430 PM EST MON DEC 30 2013
WEST-NORTHWEST WINDS WILL VEER TO THE NORTHWEST TONIGHT AND BE IN
THE 15-25KT RANGE. THERE COULD BE SOME GUSTS TO 30KTS OVER THE
EASTERN LAKE AS A MESO-LOW DEVELOPS. THESE WINDS WILL CONTINUE TO
PRODUCE SOME AREAS OF HEAVY FREEZING SPRAY AND WILL CONTINUE THE
HEAVY FREEZING SPRAY WARNING INTO WEDNESDAY MORNING OVER THE EAST.
OTHERWISE...LIGHTER WINDS ARE EXPECTED WEDNESDAY AND THURSDAY
BEFORE AN INCREASE OUT OF THE SOUTHWEST ON FRIDAY AND FRIDAY NIGHT.
THERE COULD BE A FEW GALE FORCE GUSTS TO 35KTS WHEN THIS OCCURS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL 11 AM EST /10 AM CST/ TUESDAY FOR
MIZ002-004-005-009>011-084.
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
TUESDAY FOR MIZ006-007-085.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ266.
HEAVY FREEZING SPRAY WARNING FROM 6 AM TUESDAY TO 4 AM EST
WEDNESDAY FOR LSZ248-265.
HEAVY FREEZING SPRAY WARNING FROM 10 PM THIS EVENING TO 1 AM EST
WEDNESDAY FOR LSZ243-244-264.
HEAVY FREEZING SPRAY WARNING FROM 10 PM EST /9 PM CST/ THIS
EVENING TO 10 PM EST /9 PM CST/ TUESDAY FOR LSZ241-242-263.
HEAVY FREEZING SPRAY WARNING FROM 10 PM THIS EVENING TO 4 AM EST
WEDNESDAY FOR LSZ249-250.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...SRF
LONG TERM...MCD
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
426 PM EST SUN DEC 29 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 424 PM EST SUN DEC 29 2013
ARCTIC AIR AND CONTINUED LAKE EFFECT OFF LAKE SUPERIOR WILL BE THE
MAIN CONCERNS FOR THE SHORT TERM PERIOD.
THE SURFACE LOW THAT BROUGHT THE SURGE OF COLD AIR CONTINUES TO
SLIDE EAST OF THE AREA...WHILE HIGH PRESSURE HAS BUILT INTO THE
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY. THE EXITING LOW HAS
LEFT A SURFACE TROUGH OVER EASTERN LAKE SUPERIOR. ALOFT...AREA IS
UNDER AN UPPER TROUGH THAT COVERS MUCH OF THE EASTERN CONUS AND HAS
LED TO ARCTIC AIR SPILLING SOUTHEAST OVER THE UPPER GREAT LAKES LAST
NIGHT. THIS COLD AIR HAS BEEN PRODUCING LAKE EFFECT SNOW SHOWERS IN
THE NORTH-NORTHWEST WIND LOCATIONS TODAY. LATEST RADAR/SATELLITE
DATA INDICATES THE BEST BANDS OVER FAR EASTERN MARQUETTE COUNTY
AND ALGER COUNTIES...WHERE RADAR RETURNS HAVE BEEN REACHING
7KFT. HAVE STARTED SEEING THE LOW LEVEL WINDS BACKING ASSOCIATED
WITH THE HIGH PRESSURE RIDGE OVER THE LAST FEW HOURS...ESPECIALLY
OVER THE WESTERN LAKE...AND THAT HAS STARTED TO PUSH THE BANDS OVER
MARQUETTE COUNTY EASTWARD. WITH AT LEAST HALF OF THE CLOUD BEING
ABOVE THE DGZ BASED ON RAP INITIAL SOUNDINGS...CALLS TO SPOTTERS
HAS INDICATED JUST A COUPLE INCHES OF ADDITIONAL SNOW
ACCUMULATION TODAY. THE BIGGEST ISSUE HAS BEEN THE SMALL FLAKES
REDUCING VISIBILITIES...ALONG WITH GUSTY WINDS TO 30-35MPH EAST
OF MARQUETTE...AND CAUSING BRIEF WHITEOUTS ALONG M-28 IN ALGER
COUNTY. A CALL TO THE ALGER COUNTY SHERIFF INDICATED SEVERAL
ACCIDENTS ON THAT STRETCH...WITH THEM ENCOURAGING TRAVEL ALONG
M-94 INSTEAD.
WITH THE COLD AIR IN PLACE AND SOME LOW LEVEL MOISTURE...EXPECT THE
LAKE EFFECT TO CONTINUE THROUGH THE SHORT TERM PERIOD. THE
LOCATION OF THE SNOW WILL BE DETERMINED BY BOUNDARY LAYER WINDS.
SINCE THE HIGH OVER SOUTHEAST SOUTH DAKOTA WILL DRIFT TO THE
SOUTHEAST THROUGH THE NIGHT...IT WILL PUSH A RIDGE INTO THE
SOUTHWEST HALF OF UPPER MICHIGAN. THIS RIDGE WILL DO TWO
THINGS...BACK THE WINDS TO MORE OF A WEST-NORTHWEST DIRECTION AND
CONTINUE TO PROVIDE DRY AIR AND SUBSIDENCE ABOVE 850MB. THOSE
BACKING WINDS WILL ALSO BE AIDED BY A SHORTWAVE DEPARTING THE
CANADIAN ROCKIES AND MOVING INTO THE NORTHERN PLAINS ON
MONDAY. THIS WILL LEAD TO WINDS TRANSITIONING FROM THE
NORTH-NORTHWEST LATE THIS AFTERNOON TO THE NORTHWEST THIS EVENING
AND EVENTUALLY NEARLY WESTERLY BY 18Z MONDAY. THEREFORE...WOULD
EXPECT THE PURE LAKE EFFECT BANDS (NO SHORTWAVE HELP) TO FOLLOW
SUIT. 850MB TEMPS WILL REMAIN FAIRLY STEADY THROUGH MONDAY AND
AROUND -23C...LEADING TO DELTA-T VALUES AROUND THE MID 20S. BUT
THIS COLD AIR WILL LEAD TO MUCH OF THE CLOUD BEING AT THE HIGH END
OF THE DGZ OR ABOVE IT...SO WOULD EXPECT SNOW RATIOS TO BE ON THE
LOWER END FOR LAKE EFFECT AND IN MOST SITUATIONS BELOW 20 TO 1. IN
THE STRONGEST BANDS OVER THE EAST AND THE BETTER LAKE
MODIFICATION...DID KEEP SOME LOW 20S IN THE FORECAST. AS SEEN ON
SATELLITE NEAR IRONWOOD THIS AFTERNOON...THE STRONGEST BANDS
WILL BE ON THE SOUTHWEST EDGE OF THE LES DUE TO THE ENHANCED
CONVERGENCE FROM THE BACKING WINDS. ALTHOUGH THIS WILL STRENGTHEN
THE BANDS...THINK THE CONSISTENT BACKING FLOW (ALONG WITH THE LOWER
RATIOS) WILL BE ENOUGH TO KEEP AMOUNTS GENERALLY LIGHT. HAVE KEPT
AMOUNTS FAIRLY SIMILAR TO WHAT WAS SEEN DURING THE DAY TODAY IN THE
LES LOCATIONS (1-2.5IN)...BUT DO HAVE SLIGHTLY HIGHER AMOUNTS
(APPROACHING 4) OVER THE EAST WITH THE SLOWER BACKING TREND. THE
LONGER FETCH WITH THE WEST TO WEST-SOUTHWEST WINDS OVER WESTERN
LAKE SUPERIOR COULD LEAD TO AN INCREASE IN INTENSITY OF THE MAIN
LAKE EFFECT BAND OVER THE KEWEENAW PENINSULA (NORTH OF HOUGHTON).
LAKE INDUCED EQUILIBRIUM LEVELS STILL AROUND 7KFT AND MUCH OF THE
CLOUDS IS AT HIGH END OF DGZ OR ABOVE SO WON/T GO TOO HIGH ON
AMOUNTS IN THE LATE MORNING AND INTO THE AFTERNOON...BUT COULD NEAR
LOW END ADVISORY AMOUNTS.
AS FOR SNOW HEADLINES...CANCELLED BARAGA AND SOUTHERN HOUGHTON
EARLY AND WILL ALLOW THE REST OF THE WESTERN AREAS EXPIRE AT 00Z AS
WINDS WILL DIMINISH AND JUST LIGHT SNOW WILL REMAIN. OVER THE
EAST...HAVE KEPT THEM AS IS WITH THE BAD CONDITIONS REPORTED ALONG
M-28 IN ALGER COUNTY...ALTHOUGH MOST LOCATIONS TONIGHT WILL
STRUGGLE TO REACH THE 4 INCH IN 12HR AMOUNTS DUE TO THE SMALLER
FLAKES.
AS FOR THE WIND CHILL HEADLINES...CLOUDS WILL DETERMINE THE LOWS
TONIGHT. UNFORTUNATELY IT COMES DOWN TO THE DIMINISHING LAKE
EFFECT CLOUDS OVER THE WEST AND THEN HIGH CLOUDS STREAMING IN LATE
TONIGHT AHEAD OF THE NEXT WAVE IN THE UPPER TROUGH SLIDING SOUTHEAST
THROUGH THE NORTHERN PLAINS. 12Z GFS/ECMWF ARE THE MOST AGGRESSIVE
WITH THESE HIGH CLOUD...COVERING THE WESTERN HALF OF THE CWA BY
12Z. WITH THE COLD AIR IN PLACE...THINK THAT TEMPS WILL COOL
FAIRLY QUICKLY IN AREAS THAT SKIES CLEAR. THE REGIONAL
GEM...WHICH TRADITIONALLY DOES WELL IN THESE CASES ONLY HAS LOWS
IN THE LOW TEENS BELOW ZERO ALONG THE WISCONSIN BORDER AND SINGLE
DIGITS ELSEWHERE. THIS PROVIDES SOME CONCERN TO THE GOING FORECAST
AND TWEAKED VALUES SLIGHTLY HIGHER. ON THE OTHER SIDE...18Z HRRR/RAP
FORECASTS HAVE LOWS AROUND -20 TO -23 TONIGHT...BUT IN MOST
SITUATIONS THEY ARE TOO LOW. EVEN WITH THE SLIGHT TWEAKS...WIND
CHILL ADVISORY LOOKS GOOD FOR AREAS NEAR THE WISCONSIN BORDER AND
HAVE LEFT IT AS IS. A LITTLE CONCERNED ON LAKE CLOUDS LINGERING
OVER MARQUETTE/BARAGA...BUT LOCATIONS WELL INLAND SHOULD CLEAR OUT
LATE AND ALLOW FOR TEMPS TO FALL. FINALLY...MAY NEED TO MONITOR
MENOMINEE COUNTY...AS GOING FORECAST HAS WIND CHILLS NEARING -25
OVER THE WESTERN REACHES OF THE COUNTY.
THE PREVIOUSLY MENTIONED MID/HIGH CLOUDS WILL MOVE ACROSS THE REST
OF THE CWA DURING THE DAY ON MONDAY AND LEAD TO A FILTERED SUNSHINE
AWAY FROM THE LAKE EFFECT. THERE COULD EVEN BE A FEW SNOW SHOWERS
NEAR IRONWOOD LATE MONDAY AFTERNOON ON THE NORTH EDGE OF THE WAVE
MOVING INTO WISCONSIN ON MONDAY EVENING. HIGHS ON MONDAY WILL BE
15-20 DEGREES BELOW NORMAL AND IN THE SINGLE DIGITS ABOVE ZERO FOR
MOST LOCATIONS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 425 PM EST SUN DEC 29 2013
BIGGEST CONCERNS IN THE EXTENDED FOCUS ON THE POTENTIAL FOR HEAVY
LAKE EFFECT SNOW OVER THE NE CWA MON NIGHT INTO TUESDAY AND ALSO
ADVISORY LEVEL WIND CHILLS FOR SOME AREAS INTO MIDWEEK.
MON NIGHT INTO TUE...AS THE POLAR VORTEX SLOWLY SHIFTS SE FROM
HUDSON BAY...THE MODELS SUGGEST A SHORTWAVE TROUGH WILL MOVE THROUGH
THE UPPER MS VALLEY TOWARD THE UPPER GREAT LAKES. THE BEST ISENTROPIC
LIFT NEAR THE 850 MB FRONT AND POTENTIAL FOR WIDESPREAD LIGHT SNOW
IS EXPECTED TO REMAIN TO THE SOUTH OF UPPER MI. AS THE LOW LEVEL
WINDS BACK W OR WSW AHEAD OF THE SHRTWV ON MONDAY...THE LES OVER THE
NE CWA WILL GRADUALLY LIFT TO THE NORTH AND POSSIBLY MOVE OFFSHORE
BY LATE IN THE DAY. VEERING WINDS IN THE WAKE OF THE SHRTWV WILL
PUSH THE LES BACK INTO AREAS FAVORED BY NW FLOW BY LATE EVENING.
LAKE INDUCED TROUGHING IS EXPECTED TO FOCUS THE STRONGEST LOW LEVEL
CONV BACK INTO THE NE PORTION OF THE CWA FROM P53 EASTWARD. NAM FCST
SOUNDINGS ALSO INDICATE THAT THE DGZ WILL BE MORE FAVORABLY PLACED
IN THE CONVECTIVE LAYER TO BOOST SLR VALUES AND OVERALL SNOWFALL
POTENTIAL. USING A BLEND OF THE NAM AND LOCAL WRF-ARW QPF WITH
LIKELY CONSERVATIVE SLR VALUES AROUND 20/1...CAME UP WITH TOTAL
SNOWFALL ACCUMULATION EXCEEDING A FOOT OVER ERN ALGER AND NRN LUCE
COUNTIES FOR THE MON NIGHT THROUGH TUE TIME FRAME. THUS...HAVE
DECIDED TO ISSUE A LAKE EFFECT SNOW WATCH FOR ALGER AND LUCE
COUNTIES OVER THIS TIME FRAME. NRN SCHOOLCRAFT WILL LIKELY SEE
PERIODS OF HEAVY LES AS WELL...BUT LOW-LVL CONVERGENCE WILL NOT BE
AS PERSISTENT THERE SO WILL KEEP THEM OUT OF THE WATCH...BUT FEEL
PRETTY CERTAIN THEY WILL EVENTUALLY NEED AN LES ADVISORY.
EVEN THOUGH TEMPS MAY NOT BE AS COLD EARLY TUE...SLIGHTLY STRONGER
WINDS IN THE WAKE OF THE SHORTWAVE WILL AGAIN PUSH WIND CHILLS INTO
THE -25 TO -35 ADVISORY RANGE OVER THE WEST.
WED INTO THU...THE NEXT SIGNIFICANT SHORTWAVE TROUGH IS EXPECTED TO
REMAIN WELL TO THE SOUTH BRINGING SNOW TO MAINLY IA/NRN IL/SRN WI
AND THE SOUTHERN GREAT LAKES. GREAT LAKES AGGREGATE TROUGHING WILL
INFLUENCE GENERALLY LIGHT LOW LEVEL WIND FIELDS AND THE RESULTING LES
INTO UPPER MI AS 850 MB TEMPS REMAIN IN THE -22C TO -26C RANGE. IT
APPEARS NOW THE MAIN FOCUS FOR LES ACCUMULATIONS MAY BE OVER THE
WEST AND NCNTRL PORTIONS OF THE CWA AS A N-NE FLOW IS EXPECTED TO
DEVELOP WED NIGHT INTO THU ON THE BACKSIDE OF SFC LOW PASSING SOUTH
AND THEN EAST OF THE REGION. WITH MODEL SNDGS SHOWING COMPRESSION OF
THE DGZ WITHIN THE LOWEST 2KFT OF THE ATMOSPHERE ALONG WITH
INVERSION HGTS AROUND 5 KFT...THE EXPECTED SMALLER FLAKE SIZE SHOULD
GENERALLY KEEP ACCUMULATION LIGHT FOR THE MOST PART.
FRI-SUN...MODELS WERE IN GENERAL AGREEMENT WITH TREND TOWARD A LESS
AMPLIFIED PATTERN. AS SFC HIGH PRESSURE SLIDES EAST LATE IN THE
WEEK...THE ECMWF AND GFS DEVELOP AREA OF LIGHT SNOW IN REGION OF
WAA/ISENTROPIC ASCENT AHEAD OF A SHRTWV MOVING THROUGH NW ONTARIO.
THIS SNOW LOOKS TO SPREAD INTO UPPER MI LATE FRI INTO SAT MORNING
WITH ANOTHER BAND OF SYNOPTIC SNOW ALONG COLD FRONTAL PASSAGE SAT
AFTERNOON/SAT NIGHT. EXPECT LES TO DEVELOP LATE SATURDAY NIGHT INTO
SUNDAY WITH INCREASING CAA IN NNW FLOW IN THE WAKE OF THE COLD
FRONT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1243 PM EST SUN DEC 29 2013
ARCTIC AIR MOVING SOUTHEAST ACROSS LAKE SUPERIOR WILL CONTINUE TO
PRODUCE LAKE EFFECT SNOW THIS AFTERNOON AT ALL THREE TAF SITES. THE
SITES SHOULD LARGELY STAY AT ALTERNATE LANDING MIN VISIBILITIES
FOR THE NEXT SEVERAL HOURS...BUT COULD SEE BRIEF FLUCTUATIONS UP
AND DOWN AS THE BANDS MOVE THROUGH. THEN...AS A HIGH PRESSURE RIDGE
BEGINS TO MOVE INTO WESTERN LAKE SUPERIOR LATER THIS AFTERNOON AND
TONIGHT...THE BACKING WINDS WILL SHIFT THE LAKE EFFECT AWAY FROM
KIWD/KSAW (AND CONDITIONS IMPROVING TO VFR)...ALTHOUGH IT WILL
REMAIN FOCUSED AT KCMX. THERE WILL LIKELY BE A STRONGER BAND
AFFECTING KCMX LATE TONIGHT INTO MONDAY MORNING AND WITH THE FINER
FLAKES...EXPECT THE VISIBILITIES TO BE SIMILAR TO TODAY EVEN WITH
LESS WIND. CONFIDENCE WAS LOW ON HOW FAR NORTH THE BAND WILL SHIFT
ACROSS THE KEWEENAW PENINSULA LATER MONDAY MORNING...SO HAVE
LINGERED MVFR CONDITIONS THROUGH THE END OF THE TAF PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 424 PM EST SUN DEC 29 2013
NORTHWESTERLY WINDS OF 15 TO 25 KNOTS WILL CONTINUE INTO THIS
EVENING BEFORE BACKING TO THE WEST-NORTHWEST LATE TONIGHT INTO
MONDAY. WINDS WILL WEAKEN SLIGHTLY AS THIS OCCURS AND SLOWLY
DIMINISH THE POTENTIAL FOR FREEZING SPRAY OVER THE LAKE BY MONDAY
AFTERNOON. AS THE LINGERING SURFACE TROUGH OVER EASTERN LAKE
SUPERIOR STRENGTHENS ON MONDAY NIGHT AND SHIFTS EAST ON
TUESDAY...NORTHWESTERLY WINDS WILL INCREASE WITH SOME GUSTS TO 30KTS
OVER THE EASTERN LAKE TUESDAY AFTERNOON AND EVENING. THIS WILL ALSO
BRING AN INCREASED OPPORTUNITY FOR HEAVY FREEZING SPRAY THROUGH
TUESDAY NIGHT OVER THE EASTERN HALF OF LAKE SUPERIOR. ALTHOUGH
THERE STILL WILL BE A LINGERING TROUGH OVER EASTERN LAKE SUPERIOR
INTO WEDNESDAY...HIGH PRESSURE BUILDING OVER THE UPPER MISSISSIPPI
VALLEY WILL LEAD TO LIGHTER NORTHWESTERLY WINDS FOR WEDNESDAY AND
THURSDAY...BRINGING AN END TO THE POTENTIAL FOR HEAVY FREEZING
SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY FROM MIDNIGHT EST /11 PM CST/ TONIGHT TO 10
AM EST /9 AM CST/ MONDAY FOR MIZ011-084.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST MONDAY FOR MIZ085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>003-005-009.
WIND CHILL ADVISORY UNTIL 10 AM EST /9 AM CST/ MONDAY FOR MIZ002-
009-010.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST MONDAY FOR MIZ006-007.
LAKE EFFECT SNOW WATCH FROM MONDAY EVENING THROUGH TUESDAY
EVENING FOR MIZ006-007.
WIND CHILL ADVISORY FROM 4 AM TO 10 AM EST MONDAY FOR MIZ004-005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST WEDNESDAY FOR LSZ267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ266.
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST MONDAY FOR LSZ265.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST MONDAY FOR LSZ248-
249-264.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST MONDAY FOR LSZ263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ THIS
EVENING FOR LSZ162-240>247.
HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST MONDAY FOR LSZ250-
251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
424 PM EST SUN DEC 29 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 424 PM EST SUN DEC 29 2013
ARCTIC AIR AND CONTINUED LAKE EFFECT OFF LAKE SUPERIOR WILL BE THE
MAIN CONCERNS FOR THE SHORT TERM PERIOD.
THE SURFACE LOW THAT BROUGHT THE SURGE OF COLD AIR CONTINUES TO
SLIDE EAST OF THE AREA...WHILE HIGH PRESSURE HAS BUILT INTO THE
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY. THE EXITING LOW HAS
LEFT A SURFACE TROUGH OVER EASTERN LAKE SUPERIOR. ALOFT...AREA IS
UNDER AN UPPER TROUGH THAT COVERS MUCH OF THE EASTERN CONUS AND HAS
LED TO ARCTIC AIR SPILLING SOUTHEAST OVER THE UPPER GREAT LAKES LAST
NIGHT. THIS COLD AIR HAS BEEN PRODUCING LAKE EFFECT SNOW SHOWERS IN
THE NORTH-NORTHWEST WIND LOCATIONS TODAY. LATEST RADAR/SATELLITE
DATA INDICATES THE BEST BANDS OVER FAR EASTERN MARQUETTE COUNTY
AND ALGER COUNTIES...WHERE RADAR RETURNS HAVE BEEN REACHING
7KFT. HAVE STARTED SEEING THE LOW LEVEL WINDS BACKING ASSOCIATED
WITH THE HIGH PRESSURE RIDGE OVER THE LAST FEW HOURS...ESPECIALLY
OVER THE WESTERN LAKE...AND THAT HAS STARTED TO PUSH THE BANDS OVER
MARQUETTE COUNTY EASTWARD. WITH AT LEAST HALF OF THE CLOUD BEING
ABOVE THE DGZ BASED ON RAP INITIAL SOUNDINGS...CALLS TO SPOTTERS
HAS INDICATED JUST A COUPLE INCHES OF ADDITIONAL SNOW
ACCUMULATION TODAY. THE BIGGEST ISSUE HAS BEEN THE SMALL FLAKES
REDUCING VISIBILITIES...ALONG WITH GUSTY WINDS TO 30-35MPH EAST
OF MARQUETTE...AND CAUSING BRIEF WHITEOUTS ALONG M-28 IN ALGER
COUNTY. A CALL TO THE ALGER COUNTY SHERIFF INDICATED SEVERAL
ACCIDENTS ON THAT STRETCH...WITH THEM ENCOURAGING TRAVEL ALONG
M-94 INSTEAD.
WITH THE COLD AIR IN PLACE AND SOME LOW LEVEL MOISTURE...EXPECT THE
LAKE EFFECT TO CONTINUE THROUGH THE SHORT TERM PERIOD. THE
LOCATION OF THE SNOW WILL BE DETERMINED BY BOUNDARY LAYER WINDS.
SINCE THE HIGH OVER SOUTHEAST SOUTH DAKOTA WILL DRIFT TO THE
SOUTHEAST THROUGH THE NIGHT...IT WILL PUSH A RIDGE INTO THE
SOUTHWEST HALF OF UPPER MICHIGAN. THIS RIDGE WILL DO TWO
THINGS...BACK THE WINDS TO MORE OF A WEST-NORTHWEST DIRECTION AND
CONTINUE TO PROVIDE DRY AIR AND SUBSIDENCE ABOVE 850MB. THOSE
BACKING WINDS WILL ALSO BE AIDED BY A SHORTWAVE DEPARTING THE
CANADIAN ROCKIES AND MOVING INTO THE NORTHERN PLAINS ON
MONDAY. THIS WILL LEAD TO WINDS TRANSITIONING FROM THE
NORTH-NORTHWEST LATE THIS AFTERNOON TO THE NORTHWEST THIS EVENING
AND EVENTUALLY NEARLY WESTERLY BY 18Z MONDAY. THEREFORE...WOULD
EXPECT THE PURE LAKE EFFECT BANDS (NO SHORTWAVE HELP) TO FOLLOW
SUIT. 850MB TEMPS WILL REMAIN FAIRLY STEADY THROUGH MONDAY AND
AROUND -23C...LEADING TO DELTA-T VALUES AROUND THE MID 20S. BUT
THIS COLD AIR WILL LEAD TO MUCH OF THE CLOUD BEING AT THE HIGH END
OF THE DGZ OR ABOVE IT...SO WOULD EXPECT SNOW RATIOS TO BE ON THE
LOWER END FOR LAKE EFFECT AND IN MOST SITUATIONS BELOW 20 TO 1. IN
THE STRONGEST BANDS OVER THE EAST AND THE BETTER LAKE
MODIFICATION...DID KEEP SOME LOW 20S IN THE FORECAST. AS SEEN ON
SATELLITE NEAR IRONWOOD THIS AFTERNOON...THE STRONGEST BANDS
WILL BE ON THE SOUTHWEST EDGE OF THE LES DUE TO THE ENHANCED
CONVERGENCE FROM THE BACKING WINDS. ALTHOUGH THIS WILL STRENGTHEN
THE BANDS...THINK THE CONSISTENT BACKING FLOW (ALONG WITH THE LOWER
RATIOS) WILL BE ENOUGH TO KEEP AMOUNTS GENERALLY LIGHT. HAVE KEPT
AMOUNTS FAIRLY SIMILAR TO WHAT WAS SEEN DURING THE DAY TODAY IN THE
LES LOCATIONS (1-2.5IN)...BUT DO HAVE SLIGHTLY HIGHER AMOUNTS
(APPROACHING 4) OVER THE EAST WITH THE SLOWER BACKING TREND. THE
LONGER FETCH WITH THE WEST TO WEST-SOUTHWEST WINDS OVER WESTERN
LAKE SUPERIOR COULD LEAD TO AN INCREASE IN INTENSITY OF THE MAIN
LAKE EFFECT BAND OVER THE KEWEENAW PENINSULA (NORTH OF HOUGHTON).
LAKE INDUCED EQUILIBRIUM LEVELS STILL AROUND 7KFT AND MUCH OF THE
CLOUDS IS AT HIGH END OF DGZ OR ABOVE SO WON/T GO TOO HIGH ON
AMOUNTS IN THE LATE MORNING AND INTO THE AFTERNOON...BUT COULD NEAR
LOW END ADVISORY AMOUNTS.
AS FOR SNOW HEADLINES...CANCELLED BARAGA AND SOUTHERN HOUGHTON
EARLY AND WILL ALLOW THE REST OF THE WESTERN AREAS EXPIRE AT 00Z AS
WINDS WILL DIMINISH AND JUST LIGHT SNOW WILL REMAIN. OVER THE
EAST...HAVE KEPT THEM AS IS WITH THE BAD CONDITIONS REPORTED ALONG
M-28 IN ALGER COUNTY...ALTHOUGH MOST LOCATIONS TONIGHT WILL
STRUGGLE TO REACH THE 4 INCH IN 12HR AMOUNTS DUE TO THE SMALLER
FLAKES.
AS FOR THE WIND CHILL HEADLINES...CLOUDS WILL DETERMINE THE LOWS
TONIGHT. UNFORTUNATELY IT COMES DOWN TO THE DIMINISHING LAKE
EFFECT CLOUDS OVER THE WEST AND THEN HIGH CLOUDS STREAMING IN LATE
TONIGHT AHEAD OF THE NEXT WAVE IN THE UPPER TROUGH SLIDING SOUTHEAST
THROUGH THE NORTHERN PLAINS. 12Z GFS/ECMWF ARE THE MOST AGGRESSIVE
WITH THESE HIGH CLOUD...COVERING THE WESTERN HALF OF THE CWA BY
12Z. WITH THE COLD AIR IN PLACE...THINK THAT TEMPS WILL COOL
FAIRLY QUICKLY IN AREAS THAT SKIES CLEAR. THE REGIONAL
GEM...WHICH TRADITIONALLY DOES WELL IN THESE CASES ONLY HAS LOWS
IN THE LOW TEENS BELOW ZERO ALONG THE WISCONSIN BORDER AND SINGLE
DIGITS ELSEWHERE. THIS PROVIDES SOME CONCERN TO THE GOING FORECAST
AND TWEAKED VALUES SLIGHTLY HIGHER. ON THE OTHER SIDE...18Z HRRR/RAP
FORECASTS HAVE LOWS AROUND -20 TO -23 TONIGHT...BUT IN MOST
SITUATIONS THEY ARE TOO LOW. EVEN WITH THE SLIGHT TWEAKS...WIND
CHILL ADVISORY LOOKS GOOD FOR AREAS NEAR THE WISCONSIN BORDER AND
HAVE LEFT IT AS IS. A LITTLE CONCERNED ON LAKE CLOUDS LINGERING
OVER MARQUETTE/BARAGA...BUT LOCATIONS WELL INLAND SHOULD CLEAR OUT
LATE AND ALLOW FOR TEMPS TO FALL. FINALLY...MAY NEED TO MONITOR
MENOMINEE COUNTY...AS GOING FORECAST HAS WIND CHILLS NEARING -25
OVER THE WESTERN REACHES OF THE COUNTY.
THE PREVIOUSLY MENTIONED MID/HIGH CLOUDS WILL MOVE ACROSS THE REST
OF THE CWA DURING THE DAY ON MONDAY AND LEAD TO A FILTERED SUNSHINE
AWAY FROM THE LAKE EFFECT. THERE COULD EVEN BE A FEW SNOW SHOWERS
NEAR IRONWOOD LATE MONDAY AFTERNOON ON THE NORTH EDGE OF THE WAVE
MOVING INTO WISCONSIN ON MONDAY EVENING. HIGHS ON MONDAY WILL BE
15-20 DEGREES BELOW NORMAL AND IN THE SINGLE DIGITS ABOVE ZERO FOR
MOST LOCATIONS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 455 AM EST SUN DEC 29 2013
MON INTO TUE...AS THE POLAR VORTEX SLOWLY SHIFTS SE FROM HUDSON
BAY...THE MODELS SUGGEST A SHORTWAVE TROUGH WILL MOVE THROUGH THE
UPPER MS VALLY TOWARD THE WRN GREAT LAKES. THE BEST ISENTROPIC LIFT
NEAR THE 850 MB FRONT AND POTENTIAL FOR WIDESPREAD LIGHT SNOW IS
EXPECTED TO REMAIN TO THE SOUTH OF UPPER MI. AS THE LOW LEVEL WINDS
BACK AHEAD OF THE SHRTWV...THE LES OVER THE NE CWA WILL GRADUALLY
LIFT TO THE NORTH AND POSSIBLY MOVE OFFSHORE BY LATE IN THE DAY.
ADDITIONAL SNOWFALL AMOUNTS IN THE MORNING MAY AMOUNT TO 1 TO 3
INCHES OVER FAR ERN ALGER COUNTY AND NRN LUCE COUNTY. OVER THE
WEST...CONVERGENT WRLY FLOW WILL LIKELY BRING AN INCREASE IN LES
INTENSITY OVER THE KEWEENAW. ALTHOUGH ADVY SNOWFALL AMOUNTS IN THE 2
TO 6 INCH RANGE MAY BE POSSIBLE...CONFIDENCE IN THE LOW LEVEL WIND
DETAILS IS LIMITED. VEERING WINDS IN THE WAKE OF THE SHRTWV WILL
PUSH THE LES BACK INTO AREAS FAVORED BY NW FLOW. LAKE INDUCED
TROUGHING IS EXPECTED TO FOCUS THE STRONGEST LOW LEVEL CONV BACK INTO
THE NE PORTION OF THE CWA FROM P53 EASTWARD. NAM FCST SOUNDINGS
ALSO SUGGEST THAT THE DGZ WILL BE MORE FAVORABLY PLACED IN THE
CONVECTIVE LAYER TO BOOST SLR VALUES AND OVERALL SNOWFALL
POTENTIAL.
WIND CHILL VALUES INTO THE ADVISORY RANGE FROM -25 TO -35 EARLY
MONDAY OVER THE INTERIOR WEST WILL MODERATE BY MID MORNING WITH DIURNAL
WARMING AND DIMINISHING WINDS. EVEN THOUGH TEMPS MAY NOT BE AS COLD
EARLY TUE...SLIGHTLY STRONGER WINDS WILL AGAIN PUSH WIND CHILLS INTO
THE -25 TO -35 ADVY RANGE OVER THE WEST.
WED INTO THU...THE NEXT SIGNIFICANT SHORTWAVE TROUGH IS EXPECTED TO
REMAIN WELL TO THE SOUTH BRINGING SNOW TO MAINLY IA/NRN IL/SRN WI
AND THE SOUTHERN GREAT LAKES. GREAT LAKES AGGREGATE TROUGHING WILL
INFLUENCE GENERALLY LIGHT LOW LEVEL WIND FIELDS AND THE RESULTING LES
INTO UPPER MI AS 850 MB TEMPS REMAIN IN THE -22C TO -26C RANGE. ALTHOUGH
THE MAIN FOCUS FOR HIGHER LES ACCUMULATIONS WILL REMAIN OVER THE ERN
CWA...AT LEAST LIGHT LES WILL PERSIST OVER THE WEST THROUGH THE
PERIOD.
FRI-SAT...MODELS WERE IN GENERAL AGREEMENT WITH TREND TOWARD A LESS
AMPLIFIED PATTERN. AS SFC HIGH PRESSURE SLIDES EAST LATE IN THE
WEEK...THE ECMWF AND GFS DEVELOP AREA OF LIGHT SNOW IN REGION OF
WAA/ISENTROPIC ASCENT AHEAD OF A SHRTWV MOVING INTO NW ONTARIO. THIS
SNOW LOOKS TO SPREAD INTO UPPER MI LATE FRI OR FRI NIGHT. AS SYSTEM
SNOW TAPERS OFF EARLY SAT...LES COULD DEVELOP LATE IN THE DAY AS
WINDS SHIFT TO THE NW BEHIND FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1243 PM EST SUN DEC 29 2013
ARCTIC AIR MOVING SOUTHEAST ACROSS LAKE SUPERIOR WILL CONTINUE TO
PRODUCE LAKE EFFECT SNOW THIS AFTERNOON AT ALL THREE TAF SITES. THE
SITES SHOULD LARGELY STAY AT ALTERNATE LANDING MIN VISIBILITIES
FOR THE NEXT SEVERAL HOURS...BUT COULD SEE BRIEF FLUCTUATIONS UP
AND DOWN AS THE BANDS MOVE THROUGH. THEN...AS A HIGH PRESSURE RIDGE
BEGINS TO MOVE INTO WESTERN LAKE SUPERIOR LATER THIS AFTERNOON AND
TONIGHT...THE BACKING WINDS WILL SHIFT THE LAKE EFFECT AWAY FROM
KIWD/KSAW (AND CONDITIONS IMPROVING TO VFR)...ALTHOUGH IT WILL
REMAIN FOCUSED AT KCMX. THERE WILL LIKELY BE A STRONGER BAND
AFFECTING KCMX LATE TONIGHT INTO MONDAY MORNING AND WITH THE FINER
FLAKES...EXPECT THE VISIBILITIES TO BE SIMILAR TO TODAY EVEN WITH
LESS WIND. CONFIDENCE WAS LOW ON HOW FAR NORTH THE BAND WILL SHIFT
ACROSS THE KEWEENAW PENINSULA LATER MONDAY MORNING...SO HAVE
LINGERED MVFR CONDITIONS THROUGH THE END OF THE TAF PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 424 PM EST SUN DEC 29 2013
NORTHWESTERLY WINDS OF 15 TO 25 KNOTS WILL CONTINUE INTO THIS
EVENING BEFORE BACKING TO THE WEST-NORTHWEST LATE TONIGHT INTO
MONDAY. WINDS WILL WEAKEN SLIGHTLY AS THIS OCCURS AND SLOWLY
DIMINISH THE POTENTIAL FOR FREEZING SPRAY OVER THE LAKE BY MONDAY
AFTERNOON. AS THE LINGERING SURFACE TROUGH OVER EASTERN LAKE
SUPERIOR STRENGTHENS ON MONDAY NIGHT AND SHIFTS EAST ON
TUESDAY...NORTHWESTERLY WINDS WILL INCREASE WITH SOME GUSTS TO 30KTS
OVER THE EASTERN LAKE TUESDAY AFTERNOON AND EVENING. THIS WILL ALSO
BRING AN INCREASED OPPORTUNITY FOR HEAVY FREEZING SPRAY THROUGH
TUESDAY NIGHT OVER THE EASTERN HALF OF LAKE SUPERIOR. ALTHOUGH
THERE STILL WILL BE A LINGERING TROUGH OVER EASTERN LAKE SUPERIOR
INTO WEDNESDAY...HIGH PRESSURE BUILDING OVER THE UPPER MISSISSIPPI
VALLEY WILL LEAD TO LIGHTER NORTHWESTERLY WINDS FOR WEDNESDAY AND
THURSDAY...BRINGING AN END TO THE POTENTIAL FOR HEAVY FREEZING
SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY FROM MIDNIGHT EST /11 PM CST/ TONIGHT TO 10
AM EST /9 AM CST/ MONDAY FOR MIZ011-084.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST MONDAY FOR MIZ085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>003-005-009.
WIND CHILL ADVISORY UNTIL 10 AM EST /9 AM CST/ MONDAY FOR MIZ002-
009-010.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST MONDAY FOR MIZ006-007.
LAKE EFFECT SNOW WATCH FROM MONDAY EVENING THROUGH TUESDAY
EVENING FOR MIZ006-007.
WIND CHILL ADVISORY FROM 4 AM TO 10 AM EST MONDAY FOR MIZ004-005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST WEDNESDAY FOR LSZ267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ266.
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST MONDAY FOR LSZ265.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST MONDAY FOR LSZ248-
249-264.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST MONDAY FOR LSZ263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ THIS
EVENING FOR LSZ162-240>247.
HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST MONDAY FOR LSZ250-
251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
459 AM EST SUN DEC 29 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 419 PM EST SAT DEC 28 2013
A STALLED FRONTAL BOUNDARY OVER SOUTHERN LAKE SUPERIOR AND NORTHERN
UPPER MICHIGAN HAS LED TO DREARY CONDITIONS FOR MUCH OF UPPER
MICHIGAN TODAY. ON THE PLUS SIDE...TEMPERATURES HAVE BEEN IN THE
LOW TO MID 30S ALONG AND SOUTH OF THE BOUNDARY WHERE THERE HAVE
EVEN BEEN A FEW PEAKS OF SUNSHINE. JUST TO THE NORTH OF THE
BOUNDARY...FAVORABLE EASTERLY FLOW OFF LAKE SUPERIOR HAS LED TO
SOME FZDZ...FOG...AND -SHSN OVER THE KEWEENAW PENINSULA. A SPOTTER
REPORT AROUND 3PM INDICATED A SLIGHT GLAZE IN MOHAWK SHORTLY
AFTER THE VISIBILITY REALLY DROPPED AT KCMX. THINK THAT
FREEZING DRIZZLE WILL REMAIN A THREAT OVER THE NEXT COUPLE OF HOURS
AND EVEN DRIFT SOUTHEAST THROUGH THE EVENING...AS MODELS SHOW A
LACK OF ICE CRYSTALS IN THE CLOUDS BEFORE THE MAIN PRECIPITATION
ARRIVES FROM SOUTHERN CANADA LATE THIS EVENING. ALSO FOR THIS
EVENING...DID ADD SOME PATCHY FOG OVER THE SOUTHEAST PART OF THE
CWA WHERE WINDS WILL BE LIGHT AND THERE HAVE BEEN SOME BREAKS IN
THE CLOUDS.
THE LOW THAT IS CURRENTLY CENTERED IN SOUTH CENTRAL MINNESOTA WILL
CONTINUE EAST TONIGHT AND SUNDAY...BEING CENTERED JUST NORTH OF LAKE
ONTARIO BY 00Z MONDAY. AS THIS LOW SWEEPS EAST...AN AREA OF SNOW
(CURRENTLY IN SOUTHWEST ONTARIO AND ALSO ENTERING NORTHWEST
MINNESOTA) WILL SWEEP ACROSS THE UPPER GREAT LAKES LATE THIS
EVENING THROUGH EARLY SUNDAY MORNING. THE SYNOPTIC SNOW WILL BE
AIDED BY THE RIGHT REAR OF THE 110KT UPPER JET THAT SWEEPS ACROSS
TONIGHT. IN ADDITION...POCKET OF 800-600MB FGEN WILL SLIDE THROUGH
WITH THE 850/700MB TROUGH. THUS...EXPECT A PERIOD OF LIGHT SNOW TO
MOVE ACROSS MUCH OF UPPER MICHIGAN FROM WEST TO EAST. WITH THE BEST
FORCING OVER THE NORTHERN HALF OF THE CWA...EXPECT THE BEST SYNOPTIC
SNOWFALL THERE...WHICH WILL BE AIDED BY LAKE ENHANCEMENT. OVER THE
SOUTHERN HALF...ONLY EXPECT A LIGHT DUSTING TO AN INCH AWAY FROM THE
LAKE SUPERIOR INFLUENCES WITH SNOW RATIOS AROUND NORMAL VALUES OF
13-1.
AS FOR THE LAKE ENHANCEMENT...COLD AIR SURGING IN BEHIND THE LOW
(FALLING FROM RAP ANALYZED VALUES OF 0C FROM WEST-EAST OVER THE
CENTRAL U.P. AT 20Z TO -10 TO -16C AT 12Z SUNDAY AND -23C BY 00Z
MONDAY) WILL LEAD TO LAKE ENHANCEMENT FOR AREAS NEAR LAKE SUPERIOR
AS THE WIND DIRECTIONS BECOME FAVORABLE. THE WINDS WILL BE OUT OF
THE NORTHEAST INITIALLY THIS EVENING OVER WESTERN LAKE
SUPERIOR...BUT AS THE SURFACE/925MB LOW MOVES EAST-NORTHEAST THROUGH
NORTHEAST WISCONSIN AND SOUTH CENTRAL UPPER MICHIGAN TONIGHT...THE
WINDS WILL TRANSITION TO THE NORTH OVERNIGHT...NNW SUNDAY
MORNING...AND THEN NW SUNDAY AFTERNOON. THUS...EXPECT THE INITIAL
ENHANCEMENT TO OCCUR LATE IN THE EVENING OVER THE NE FAVORED
LOCATIONS AND THEN TRANSITION WITH THE WINDS INTO SUNDAY MORNING.
THESE STEADY BACKING WINDS WILL LIKELY BE ONE OF THE LIMITING
FACTORS TO HEAVIER SNOWFALL AMOUNTS. THE SECOND ITEM THAT SHOULD
KEEP SNOWFALL AMOUNTS IN THE LES ADVISORY CATEGORY WILL BE THE SHORT
PERIOD WHEN THE LAKE ENHANCEMENT AND LOW LEVEL TEMPERATURE PROFILE
FALL WITHIN THE DGZ. AT MOST LOCATIONS...IT APPEARS LIKE IT WILL
ONLY OCCUR FOR A 3 TO MAYBE 6HOUR PERIOD. THUS...EVEN THOUGH SNOW
RATIOS WILL QUICKLY RISE TO THE LOWER 20S...THEY WILL QUICKLY FALL
ONCE THE DEEPER MOISTURE DEPARTS AND THE INCREASING COLD AIR MOVES
THE CLOUD OUT OF THE DGZ. FINALLY...GUSTY WINDS MAY LIMIT SNOW
RATIOS FROM GROWING MUCH ABOVE 22/23-1 DURING THE FAVORED
PERIOD...EVEN THOUGH ALL OF THE CLOUD IS WITHIN THE DGZ.
OVERALL...ONLY MADE MINOR TWEAKS TO MUCH OF THE SNOWFALL FORECAST
FOR TONIGHT INTO SUNDAY MORNING...LARGELY WITH HANDLING THE TIMING
OF THE CHANGE OVER TO SNOW FROM NORTHWEST TO SOUTHEAST. THE FAVORED
HIGHER TERRAIN LOCATIONS WILL LIKELY SEE AMOUNTS THROUGH SUNDAY
MORNING IN THE 3-8INCH RANGE...WITH THE GREATEST AMOUNTS OVER THE
HURON MOUNTAINS WITH THE LONGER PERIOD OF FAVORABLE WIND
DIRECTIONS. THAT WOULD BE THE ONLY LOCATIONS WHERE SOME CONCERN OF
NEAR WARNING AMOUNT SNOW WOULD OCCUR...BUT THE SOCIETAL IMPACT WILL
BE LIMITED.
DEEPER MOISTURE FROM THE LOW PULLS OUT QUICKLY FROM WEST TO EAST ON
SUNDAY MORNING AND LEADS TO A TRANSITION TO PURE LAKE EFFECT. WITH
THAT DEEPER MOISTURE DEPARTING...MODELS ARE ONLY SHOWING MOISTURE
AND INVERSION HEIGHTS AROUND 4KFT...BUT WITH LAKE INDUCED
EQUILIBRIUM LEVELS AROUND 5-6KFT...COULD STILL BE SOME STRONGER SNOW
SHOWERS. BUT WITH COLDER AIR CONTINUING TO SURGE IN...MUCH OF THE
CLOUD LAYER WILL MOVE TO THE TOP OF OR ABOVE THE DGZ...WHICH SHOULD
LEAD TO A TRANSITION TO MORE OF COLUMN/PLATES. THEREFORE...WILL
CONTINUE THE IDEA OF LOWERING SNOW RATIOS TO THE HIGH TEENS OR
AROUND 20-1 FROM WEST TO EAST THROUGH THE DAY SUNDAY. THIS SHOULD
LEAD TO LESSER SNOWFALL AMOUNTS IN THE AFTERNOON...WHICH WILL STILL
BE AIDED BY SLOWLY BACKING WINDS TO THE NORTHWEST. OVERALL...HAVE
AFTERNOON AMOUNTS OF 1-2 INCHES IN MOST LOCATIONS...WITH SLIGHTLY
HIGHER VALUES OVER WESTERN ALGER COUNTY. THEREFORE...WILL KEEP LES
ADVISORIES AS IS...ALTHOUGH THE LONG TERM DID MAKE SOME ADJUSTMENTS
TO ALGER TO EXTEND INTO MONDAY. THINK THAT COVERS THE OVERALL IDEA
VERY WELL...SINCE THE NEGATIVES WITH SNOW RATIOS AND BACKING WINDS
SHOULD LIMIT THE POTENTIAL FOR 12HR SNOW AMOUNTS REACHING WARNING
VALUES.
THE COLD AIR SURGING IN WILL LEAD TO FALLING TEMPERATURES STARTING
LATE THIS EVENING OVER THE WEST AND PUSHING ACROSS THE REST OF THE
AREA THROUGH THE NIGHT. OVERNIGHT LOWS FOR TONIGHT AND HIGHS FOR
TOMORROW ARE FAIRLY TRICKY...AS THEY BOTH WILL LIKELY OCCUR DURING
THE TWO HOUR OVERLAP BETWEEN 12-14Z. THUS...TRIED TO FOCUS ON TEMPS
DURING THAT PERIOD TO USE FOR SIMILAR VALUES. WITH THE COLD AIR
CONTINUING TO SURGE IN THROUGH THE DAY ON SUNDAY...EXPECT STEADY OR
SLOWLY FALLING TEMPERATURES THROUGH THE REST OF THE DAY ON
SUNDAY. AFTERNOON VALUES OVER THE WEST WILL BE IN THE LOWER SINGLE
DIGITS ABOVE ZERO AND AROUND 10 DEGREES OVER THE EAST HALF.
FACTORING IN WIND CHILLS...TOMORROW AFTERNOON WILL FEEL ABOUT 50
DEGREES COLDER THAN THIS PAST AFTERNOON.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 455 AM EST SUN DEC 29 2013
MON INTO TUE...AS THE POLAR VORTEX SLOWLY SHIFTS SE FROM HUDSON
BAY...THE MODELS SUGGEST A SHORTWAVE TROUGH WILL MOVE THROUGH THE
UPPER MS VALLY TOWARD THE WRN GREAT LAKES. THE BEST ISENTROPIC LIFT
NEAR THE 850 MB FRONT AND POTENTIAL FOR WIDESPREAD LIGHT SNOW IS
EXPECTED TO REMAIN TO THE SOUTH OF UPPER MI. AS THE LOW LEVEL WINDS
BACK AHEAD OF THE SHRTWV...THE LES OVER THE NE CWA WILL GRADUALLY
LIFT TO THE NORTH AND POSSIBLY MOVE OFFSHORE BY LATE IN THE DAY.
ADDITIONAL SNOWFALL AMOUNTS IN THE MORNING MAY AMOUNT TO 1 TO 3
INCHES OVER FAR ERN ALGER COUNTY AND NRN LUCE COUNTY. OVER THE
WEST...CONVERGENT WRLY FLOW WILL LIKELY BRING AN INCREASE IN LES
INTENSITY OVER THE KEWEENAW. ALTHOUGH ADVY SNOWFALL AMOUNTS IN THE 2
TO 6 INCH RANGE MAY BE POSSIBLE...CONFIDENCE IN THE LOW LEVEL WIND
DETAILS IS LIMITED. VEERING WINDS IN THE WAKE OF THE SHRTWV WILL
PUSH THE LES BACK INTO AREAS FAVORED BY NW FLOW. LAKE INDUCED
TROUGHING IS EXPECTED TO FOCUS THE STRONGEST LOW LEVEL CONV BACK INTO
THE NE PORTION OF THE CWA FROM P53 EASTWARD. NAM FCST SOUNDINGS
ALSO SUGGEST THAT THE DGZ WILL BE MORE FAVORABLY PLACED IN THE
CONVECTIVE LAYER TO BOOST SLR VALUES AND OVERALL SNOWFALL
POTENTIAL.
WIND CHILL VALUES INTO THE ADVISORY RANGE FROM -25 TO -35 EARLY
MONDAY OVER THE INTERIOR WEST WILL MODERATE BY MID MORNING WITH DIURNAL
WARMING AND DIMINISHING WINDS. EVEN THOUGH TEMPS MAY NOT BE AS COLD
EARLY TUE...SLIGHTLY STRONGER WINDS WILL AGAIN PUSH WIND CHILLS INTO
THE -25 TO -35 ADVY RANGE OVER THE WEST.
WED INTO THU...THE NEXT SIGNIFICANT SHORTWAVE TROUGH IS EXPECTED TO
REMAIN WELL TO THE SOUTH BRINGING SNOW TO MAINLY IA/NRN IL/SRN WI
AND THE SOUTHERN GREAT LAKES. GREAT LAKES AGGREGATE TROUGHING WILL
INFLUENCE GENERALLY LIGHT LOW LEVEL WIND FIELDS AND THE RESULTING LES
INTO UPPER MI AS 850 MB TEMPS REMAIN IN THE -22C TO -26C RANGE. ALTHOUGH
THE MAIN FOCUS FOR HIGHER LES ACCUMULATIONS WILL REMAIN OVER THE ERN
CWA...AT LEAST LIGHT LES WILL PERSIST OVER THE WEST THROUGH THE
PERIOD.
FRI-SAT...MODELS WERE IN GENERAL AGREEMENT WITH TREND TOWARD A LESS
AMPLIFIED PATTERN. AS SFC HIGH PRESSURE SLIDES EAST LATE IN THE
WEEK...THE ECMWF AND GFS DEVELOP AREA OF LIGHT SNOW IN REGION OF
WAA/ISENTROPIC ASCENT AHEAD OF A SHRTWV MOVING INTO NW ONTARIO. THIS
SNOW LOOKS TO SPREAD INTO UPPER MI LATE FRI OR FRI NIGHT. AS SYSTEM
SNOW TAPERS OFF EARLY SAT...LES COULD DEVELOP LATE IN THE DAY AS
WINDS SHIFT TO THE NW BEHIND FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1226 AM EST SUN DEC 29 2013
PERIODS OF -SN/-SHSN/BLSN WITH IFR CONDITIONS IN THE GUSTY N FLOW IN
THE WAKE OF LO PRES SHIFTING TO THE E THRU THE CENTRAL GRT LKS WL
GIVE WAY TO MVFR CONDITIONS ON SUN AS STRONG SUBSIDENCE/DIMINISHING
WINDS WEAKEN THE SN/GUSTY WINDS/BLSN. THE MOST RAPID IMPROVEMENT WL
OCCUR AT CMX...WHERE THE EXPECTED N WIND DOES NOT PRESENT AS SGNFT
AN UPSLOPE WIND COMPONENT. BUT AS THE FLOW CONTINUES TO BACK TO THE
NW ON SUN AFTN/EVNG...IFR VSBYS WL REDVLP THERE WITH A MORE FVRBL
WIND. AT THE SAME TIME...THE DOWNSLOPE NATURE OF THE FLOW INTO SAW
WL CAUSE VFR CONDITIONS BY LATER IN THE DAY ON SUN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EST SAT DEC 28 2013
WINDS TO STAY LIGHT UNTIL SFC LOW BRINGS TIGHTENING PRESSURE
GRADIENT TO WESTERN LAKE SUPERIOR THIS AFTERNOON. BY LATE
AFTERNOON...WILL SEE FREQUENT GALE FORCE GUSTS OVER WESTERN LAKE
SUPERIOR WITH NE GALES EXPECTED BY THE EVENING. AS THE SFC LOW
PASSES TO THE SE OF THE AREA OVERNIGHT...NORTH WINDS TO GRADUALLY
RELAX. MUCH COLDER AIR ARRIVING TONIGHT WILL PRODUCE HEAVY FREEZING
SPRAY AS WELL. WINDS GO BELOW 25 KNOTS SUNDAY AFTERNOON AND BELOW 20
KNOTS BY MONDAY AFTERNOON. WINDS REMAIN BELOW 20 KNOTS THROUGH THE
REMAINDER OF THE FORECAST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>005-009-084.
WIND CHILL ADVISORY FROM MIDNIGHT EST /11 PM CST/ TONIGHT TO 10
AM EST /9 AM CST/ MONDAY FOR MIZ011-084.
LAKE EFFECT SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ085.
WIND CHILL ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO 10
AM EST /9 AM CST/ MONDAY FOR MIZ002-009-010.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST MONDAY FOR MIZ006.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 1 PM EST
MONDAY FOR MIZ007.
WIND CHILL ADVISORY FROM 4 AM TO 10 AM EST MONDAY FOR MIZ004-005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST WEDNESDAY FOR LSZ267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ265-
266.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LSZ263>266.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST MONDAY FOR LSZ248-
249-264.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST MONDAY FOR LSZ263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ THIS
EVENING FOR LSZ162-240>247.
HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST MONDAY FOR LSZ250-
251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1226 AM EST SUN DEC 29 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 419 PM EST SAT DEC 28 2013
A STALLED FRONTAL BOUNDARY OVER SOUTHERN LAKE SUPERIOR AND NORTHERN
UPPER MICHIGAN HAS LED TO DREARY CONDITIONS FOR MUCH OF UPPER
MICHIGAN TODAY. ON THE PLUS SIDE...TEMPERATURES HAVE BEEN IN THE
LOW TO MID 30S ALONG AND SOUTH OF THE BOUNDARY WHERE THERE HAVE
EVEN BEEN A FEW PEAKS OF SUNSHINE. JUST TO THE NORTH OF THE
BOUNDARY...FAVORABLE EASTERLY FLOW OFF LAKE SUPERIOR HAS LED TO
SOME FZDZ...FOG...AND -SHSN OVER THE KEWEENAW PENINSULA. A SPOTTER
REPORT AROUND 3PM INDICATED A SLIGHT GLAZE IN MOHAWK SHORTLY
AFTER THE VISIBILITY REALLY DROPPED AT KCMX. THINK THAT
FREEZING DRIZZLE WILL REMAIN A THREAT OVER THE NEXT COUPLE OF HOURS
AND EVEN DRIFT SOUTHEAST THROUGH THE EVENING...AS MODELS SHOW A
LACK OF ICE CRYSTALS IN THE CLOUDS BEFORE THE MAIN PRECIPITATION
ARRIVES FROM SOUTHERN CANADA LATE THIS EVENING. ALSO FOR THIS
EVENING...DID ADD SOME PATCHY FOG OVER THE SOUTHEAST PART OF THE
CWA WHERE WINDS WILL BE LIGHT AND THERE HAVE BEEN SOME BREAKS IN
THE CLOUDS.
THE LOW THAT IS CURRENTLY CENTERED IN SOUTH CENTRAL MINNESOTA WILL
CONTINUE EAST TONIGHT AND SUNDAY...BEING CENTERED JUST NORTH OF LAKE
ONTARIO BY 00Z MONDAY. AS THIS LOW SWEEPS EAST...AN AREA OF SNOW
(CURRENTLY IN SOUTHWEST ONTARIO AND ALSO ENTERING NORTHWEST
MINNESOTA) WILL SWEEP ACROSS THE UPPER GREAT LAKES LATE THIS
EVENING THROUGH EARLY SUNDAY MORNING. THE SYNOPTIC SNOW WILL BE
AIDED BY THE RIGHT REAR OF THE 110KT UPPER JET THAT SWEEPS ACROSS
TONIGHT. IN ADDITION...POCKET OF 800-600MB FGEN WILL SLIDE THROUGH
WITH THE 850/700MB TROUGH. THUS...EXPECT A PERIOD OF LIGHT SNOW TO
MOVE ACROSS MUCH OF UPPER MICHIGAN FROM WEST TO EAST. WITH THE BEST
FORCING OVER THE NORTHERN HALF OF THE CWA...EXPECT THE BEST SYNOPTIC
SNOWFALL THERE...WHICH WILL BE AIDED BY LAKE ENHANCEMENT. OVER THE
SOUTHERN HALF...ONLY EXPECT A LIGHT DUSTING TO AN INCH AWAY FROM THE
LAKE SUPERIOR INFLUENCES WITH SNOW RATIOS AROUND NORMAL VALUES OF
13-1.
AS FOR THE LAKE ENHANCEMENT...COLD AIR SURGING IN BEHIND THE LOW
(FALLING FROM RAP ANALYZED VALUES OF 0C FROM WEST-EAST OVER THE
CENTRAL U.P. AT 20Z TO -10 TO -16C AT 12Z SUNDAY AND -23C BY 00Z
MONDAY) WILL LEAD TO LAKE ENHANCEMENT FOR AREAS NEAR LAKE SUPERIOR
AS THE WIND DIRECTIONS BECOME FAVORABLE. THE WINDS WILL BE OUT OF
THE NORTHEAST INITIALLY THIS EVENING OVER WESTERN LAKE
SUPERIOR...BUT AS THE SURFACE/925MB LOW MOVES EAST-NORTHEAST THROUGH
NORTHEAST WISCONSIN AND SOUTH CENTRAL UPPER MICHIGAN TONIGHT...THE
WINDS WILL TRANSITION TO THE NORTH OVERNIGHT...NNW SUNDAY
MORNING...AND THEN NW SUNDAY AFTERNOON. THUS...EXPECT THE INITIAL
ENHANCEMENT TO OCCUR LATE IN THE EVENING OVER THE NE FAVORED
LOCATIONS AND THEN TRANSITION WITH THE WINDS INTO SUNDAY MORNING.
THESE STEADY BACKING WINDS WILL LIKELY BE ONE OF THE LIMITING
FACTORS TO HEAVIER SNOWFALL AMOUNTS. THE SECOND ITEM THAT SHOULD
KEEP SNOWFALL AMOUNTS IN THE LES ADVISORY CATEGORY WILL BE THE SHORT
PERIOD WHEN THE LAKE ENHANCEMENT AND LOW LEVEL TEMPERATURE PROFILE
FALL WITHIN THE DGZ. AT MOST LOCATIONS...IT APPEARS LIKE IT WILL
ONLY OCCUR FOR A 3 TO MAYBE 6HOUR PERIOD. THUS...EVEN THOUGH SNOW
RATIOS WILL QUICKLY RISE TO THE LOWER 20S...THEY WILL QUICKLY FALL
ONCE THE DEEPER MOISTURE DEPARTS AND THE INCREASING COLD AIR MOVES
THE CLOUD OUT OF THE DGZ. FINALLY...GUSTY WINDS MAY LIMIT SNOW
RATIOS FROM GROWING MUCH ABOVE 22/23-1 DURING THE FAVORED
PERIOD...EVEN THOUGH ALL OF THE CLOUD IS WITHIN THE DGZ.
OVERALL...ONLY MADE MINOR TWEAKS TO MUCH OF THE SNOWFALL FORECAST
FOR TONIGHT INTO SUNDAY MORNING...LARGELY WITH HANDLING THE TIMING
OF THE CHANGE OVER TO SNOW FROM NORTHWEST TO SOUTHEAST. THE FAVORED
HIGHER TERRAIN LOCATIONS WILL LIKELY SEE AMOUNTS THROUGH SUNDAY
MORNING IN THE 3-8INCH RANGE...WITH THE GREATEST AMOUNTS OVER THE
HURON MOUNTAINS WITH THE LONGER PERIOD OF FAVORABLE WIND
DIRECTIONS. THAT WOULD BE THE ONLY LOCATIONS WHERE SOME CONCERN OF
NEAR WARNING AMOUNT SNOW WOULD OCCUR...BUT THE SOCIETAL IMPACT WILL
BE LIMITED.
DEEPER MOISTURE FROM THE LOW PULLS OUT QUICKLY FROM WEST TO EAST ON
SUNDAY MORNING AND LEADS TO A TRANSITION TO PURE LAKE EFFECT. WITH
THAT DEEPER MOISTURE DEPARTING...MODELS ARE ONLY SHOWING MOISTURE
AND INVERSION HEIGHTS AROUND 4KFT...BUT WITH LAKE INDUCED
EQUILIBRIUM LEVELS AROUND 5-6KFT...COULD STILL BE SOME STRONGER SNOW
SHOWERS. BUT WITH COLDER AIR CONTINUING TO SURGE IN...MUCH OF THE
CLOUD LAYER WILL MOVE TO THE TOP OF OR ABOVE THE DGZ...WHICH SHOULD
LEAD TO A TRANSITION TO MORE OF COLUMN/PLATES. THEREFORE...WILL
CONTINUE THE IDEA OF LOWERING SNOW RATIOS TO THE HIGH TEENS OR
AROUND 20-1 FROM WEST TO EAST THROUGH THE DAY SUNDAY. THIS SHOULD
LEAD TO LESSER SNOWFALL AMOUNTS IN THE AFTERNOON...WHICH WILL STILL
BE AIDED BY SLOWLY BACKING WINDS TO THE NORTHWEST. OVERALL...HAVE
AFTERNOON AMOUNTS OF 1-2 INCHES IN MOST LOCATIONS...WITH SLIGHTLY
HIGHER VALUES OVER WESTERN ALGER COUNTY. THEREFORE...WILL KEEP LES
ADVISORIES AS IS...ALTHOUGH THE LONG TERM DID MAKE SOME ADJUSTMENTS
TO ALGER TO EXTEND INTO MONDAY. THINK THAT COVERS THE OVERALL IDEA
VERY WELL...SINCE THE NEGATIVES WITH SNOW RATIOS AND BACKING WINDS
SHOULD LIMIT THE POTENTIAL FOR 12HR SNOW AMOUNTS REACHING WARNING
VALUES.
THE COLD AIR SURGING IN WILL LEAD TO FALLING TEMPERATURES STARTING
LATE THIS EVENING OVER THE WEST AND PUSHING ACROSS THE REST OF THE
AREA THROUGH THE NIGHT. OVERNIGHT LOWS FOR TONIGHT AND HIGHS FOR
TOMORROW ARE FAIRLY TRICKY...AS THEY BOTH WILL LIKELY OCCUR DURING
THE TWO HOUR OVERLAP BETWEEN 12-14Z. THUS...TRIED TO FOCUS ON TEMPS
DURING THAT PERIOD TO USE FOR SIMILAR VALUES. WITH THE COLD AIR
CONTINUING TO SURGE IN THROUGH THE DAY ON SUNDAY...EXPECT STEADY OR
SLOWLY FALLING TEMPERATURES THROUGH THE REST OF THE DAY ON
SUNDAY. AFTERNOON VALUES OVER THE WEST WILL BE IN THE LOWER SINGLE
DIGITS ABOVE ZERO AND AROUND 10 DEGREES OVER THE EAST HALF.
FACTORING IN WIND CHILLS...TOMORROW AFTERNOON WILL FEEL ABOUT 50
DEGREES COLDER THAN THIS PAST AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 445 PM EST SAT DEC 28 2013
SUN NIGHT INTO MONDAY...ENHANCED LOW-LEVEL CONVERGENCE FROM
DEVELOPING LAND BREEZES AND LAKE-INDUCED TROUGHING WILL FAVOR
ALGER...NRN SCHOOLCRAFT AND LUCE COUNTIES FOR POTENTIAL ADVISORY
CRITERIA SNOWFALL. LES ADVISORIES WILL THEN LIKELY BE NEEDED FOR
THAT PORTION OF THE NE CWA WITH ADDITIONAL ACCUMULATIONS IN THE 3 TO
8 INCH RANGE FROM SUN NIGHT INTO MON MORNING.
WINDS ARE EXPECTED TO STEADILY BACK FROM NNW SUN EVENING TO WRLY BY
EARLY MON AFTERNOON AS SFC HIGH PRESSURE SLIDES FROM THE NRN PLAINS
INTO THE MID MISSISSIPPI VALLEY. THE STEADILY BACKING WINDS WILL
TEND TO SPREAD LES ACCUMULATION AROUND KEEPING MOST AREAS ON THE
LOWER END OF ADVISORY CRITERIA. FAR ERN ALGER AND NRN LUCE WILL BE
THE EXCEPTION WHERE MODELS INDICATE A LONGER PERIOD OF ENHANCED
LOW-LVL CONVERGENCE PARTICULARLY LATE SUN NIGHT INTO MONDAY
WHICH WILL LIKELY PUSH SNOWFALL AMOUNTS ON THE HIGHER END OF
ADVISORY CRITERIA (NEAR 8"). THE VERY DRY COLD ARCTIC AIRMASS ALONG
WITH THE SHORTER FETCH INTO NW UPPER MI WILL MAKE IT LESS FAVORABLE
FOR SIGNIFICANT LES THERE. ADDITIONAL LES WILL BE MORE ON THE ORDER
OF 2 TO LOCALLY 5 INCHES FOR SUN NIGHT INTO MON MORNING SO DO NOT
ANTICIPATE A NEED TO EXTEND LES ADVISORY THERE BEYOND SUNDAY.
HOWEVER...SOME OF THE MESOSCALE MODELS INDICATE THAT LOW-LVL
CONVERGENCE COULD INCREASE AND SOME ENHANCEMENT IS POSSIBLE WITH THE
APPROACH OF THE NEXT CLIPPER SHORTWAVE WHICH SHOULD FOCUS SOME
LOCALLY HEAVIER LES BANDS AND HIGHER ACCUMS BACK OVER THE KEWEENAW
MON AFTERNOON INTO MON EVENING...BUT FOR NOW THIS IS JUST REFLECTED
IN THE FCST GRIDS AND NO HEADLINE IS NEEDED YET.
THE OTHER ISSUE FOR SUNDAY NIGHT INTO MONDAY MORNING WILL BE THE
BITTER COLD ARCTIC AIRMASS SPREADING OVER THE REGION. WITH 8H TEMPS
FROM -22C TO -24C AND WINDS BACKING OFFSHORE TO A MORE WRLY
DIRECTION...THE WESTERN INTERIOR OF THE FCST AREA PARTICULARLY ALONG
THE WI BDR WILL BE UNDER THE GUN FOR ADVISORY CRITERIA WIND CHILLS
OF 25 TO 35 BELOW SUNDAY NIGHT INTO MON MORNING. GIVEN THE FOCUS ON
THE PRESENT LES HEADLINES ELECTED TO HOLD OFF ON WIND CHILL
ADVISORIES FOR NOW...BUT NO DOUBT ONE WILL BE NEEDED FOR A GOOD
PORTION OF THE WESTERN INTERIOR SUN NIGHT INTO MON MORNING.
MON NIGHT-THU...AS MODELS SHOW THE POLAR VORTEX GRADUALLY SHIFTING
FROM HUDSON BAY TO NRN QUEBEC BY TUE EVENING...VERY COLD ARCTIC AIR
WILL DOMINATE THE UPPER GREAT LAKES THROUGH MIDWEEK. WITH 850 MB
TEMPS DROPPING INTO THE -24C TO -29C RANGE...LES WILL PERSIST FOR
LOCATIONS FAVORED BY NW TO WNW FLOW. MODELS IN GOOD AGREEMENT WITH
TIMING OF NEXT CLIPPER SHORTWAVE ACROSS THE AREA MON NIGHT INTO TUE
MORNING. THIS SHORTWAVE WILL REINFORCE ARCTIC AIR WHILE ALSO
SPREADING MID Q-VECT CONV AND DEEPER MOISTURE ACROSS THE REGION.
MODELS INDICATE THIS SHORTWAVE COULD PROVIDE ENHANCEMENT TO LES
WHILE ALSO SHARPENING LAKE-INDUCED TROFFING AND LOW-LVL CONVERGENCE
OVER ERN LAKE SUPERIOR. WHILE THE INFLUX OF COLDER -24 TO -27C 8H
TEMPS BY TUESDAY WILL EVENTUALLY LEAD TO POOR SNOW GROWTH AND
SMALLER SNOWFLAKES...THE WRF-ARW BUFR SNDG FOR GRAND MARAIS MON
NIGHT INTO EARLY TUE SHOWS A SOMEWHAT FAVORABLE SNOW GROWTH PROFILE
WITH THE DGZ INITIALLY INTERSECTING THE BETTER MODEL OMEGA FOCUSED
WITHIN THE CONVECTIVE BOUNDARY LAYER. THIS COULD INITIALLY LEAD TO
HIGHER SLR/S...FLUFFIER SNOW AND GREATER ACCUMULATIONS ESPECIALLY
FOR ERN ALGER AND LUCE COUNTIES. GIVEN THE ABOVE FAVORABLE FACTORS
AND POTENTIAL FOR ENHANCEMENT THERE IS A POTENTIAL FOR HIGH END
ADVISORY LES ACCUMS POSSIBLY PUSHING LES WARNING AMTS MON NIGHT INTO
TUE MORNING FOR ERN ALGER AND LUCE COUNTIES. AFTER TUESDAY...MODELS NOT
INDICATING ANY DISCERNIBLE CLIPPER SHORTWAVES FOR MIDWEEK AS 850 MB
TEMPS GENERALLY REMAIN IN THE -22 TO -26C RANGE. THE COLDER AIRMASS
WILL GENERALLY FAVOR SMALL SNOWFLAKES WITH THE ABSENCE OF
ENHANCEMENT/DEEPER MOISTURE WHICH WILL LIMIT OVERALL ACCUMULATIONS
BUT STILL LEAD TO LOW VISIBILITIES. OUTSIDE OF THE LES...SEVERE WIND
CHILLS CAN BE EXPECTED AT TIMES AS VALUES DROP INTO THE -20 TO -35
RANGE...MAINLY IN THE NIGHTTIME AND MORNING HRS.
MODELS SHOW SIGNS OF TRENDING TOWARD LESS AMPLIFIED PATTERN BY THE
END OF THE WEEK WITH WAA DEVELOPING BY FRI. AS SFC HIGH PRESSURE
SLIDES EAST LATE IN THE WEEK...BOTH THE ECMWF AND GFS DEVELOP AREA
OF LIGHT SNOW IN REGION OF WAA/ISENTROPIC ASCENT AHEAD OF A SHRTWV
MOVING DOWN FM NW ONTARIO. THIS SNOW LOOKS TO SPREAD INTO UPPER MI
LATE FRI OR FRI NIGHT. AS SYSTEM SNOW TAPERS OFF EARLY SAT...LIGHT
LES COULD DEVELOP LATE IN THE DAY AS WINDS SHIFT NORTHERLY BEHIND
FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1226 AM EST SUN DEC 29 2013
PERIODS OF -SN/-SHSN/BLSN WITH IFR CONDITIONS IN THE GUSTY N FLOW IN
THE WAKE OF LO PRES SHIFTING TO THE E THRU THE CENTRAL GRT LKS WL
GIVE WAY TO MVFR CONDITIONS ON SUN AS STRONG SUBSIDENCE/DIMINISHING
WINDS WEAKEN THE SN/GUSTY WINDS/BLSN. THE MOST RAPID IMPROVEMENT WL
OCCUR AT CMX...WHERE THE EXPECTED N WIND DOES NOT PRESENT AS SGNFT
AN UPSLOPE WIND COMPONENT. BUT AS THE FLOW CONTINUES TO BACK TO THE
NW ON SUN AFTN/EVNG...IFR VSBYS WL REDVLP THERE WITH A MORE FVRBL
WIND. AT THE SAME TIME...THE DOWNSLOPE NATURE OF THE FLOW INTO SAW
WL CAUSE VFR CONDITIONS BY LATER IN THE DAY ON SUN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EST SAT DEC 28 2013
WINDS TO STAY LIGHT UNTIL SFC LOW BRINGS TIGHTENING PRESSURE
GRADIENT TO WESTERN LAKE SUPERIOR THIS AFTERNOON. BY LATE
AFTERNOON...WILL SEE FREQUENT GALE FORCE GUSTS OVER WESTERN LAKE
SUPERIOR WITH NE GALES EXPECTED BY THE EVENING. AS THE SFC LOW
PASSES TO THE SE OF THE AREA OVERNIGHT...NORTH WINDS TO GRADUALLY
RELAX. MUCH COLDER AIR ARRIVING TONIGHT WILL PRODUCE HEAVY FREEZING
SPRAY AS WELL. WINDS GO BELOW 25 KNOTS SUNDAY AFTERNOON AND BELOW 20
KNOTS BY MONDAY AFTERNOON. WINDS REMAIN BELOW 20 KNOTS THROUGH THE
REMAINDER OF THE FORECAST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>005-009-084.
LAKE EFFECT SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ085.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST MONDAY FOR MIZ006.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 1 PM EST
MONDAY FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST WEDNESDAY FOR
LSZ265>267.
GALE WARNING UNTIL 7 AM EST /6 AM CST/ THIS MORNING FOR LSZ162-
263>266.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
MONDAY FOR LSZ162-263-264.
HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST MONDAY FOR
LSZ248>251.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ THIS
EVENING FOR LSZ240>247.
GALE WARNING UNTIL 5 AM EST /4 AM CST/ EARLY THIS MORNING FOR
LSZ240-241.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
834 PM MST MON DEC 30 2013
.UPDATE...
WE UPDATED THE FORECAST TO INCREASE POPS WELL INTO THE CATEGORICAL
/80-100 PERCENT/ RANGE OVER MUCH OF SOUTHEASTERN MT OVERNIGHT. THE
BAND OF LIGHT SNOW ORGANIZING OVER CENTRAL MT AT 03 UTC WILL SLIDE
THROUGH MILES CITY...BAKER...AND LIKELY EKALAKA FROM 06 TO 12 UTC.
MID-LEVEL WARM AIR ADVECTION WILL DRIVE THE SNOW...AND ACT TO KEEP
OMEGA FOCUSED IN A LAYER MAINLY WARMER THAN -15 C...WHICH WILL END
UP KEEPING SNOW-TO-LIQUID RATIOS 15 TO 1 OR LOWER. THAT MEANS SNOW
TOTALS WILL MAINLY BE AN INCH OR TWO BY MIDDAY TUE...NOT ENOUGH TO
REQUIRE AN ADVISORY. IN THE HYSHAM...FORSYTH...AND BROADUS AREAS A
SLIGHT CHANCE OF FREEZING RAIN AND SLEET WAS ADDED WITH THE CHANCE
OF SNOW OVERNIGHT TOO GIVEN WARMING ALOFT AND SOME MARGINAL SIGNAL
FOR MIXED PRECIPITATION IN THE 15 UTC SREF AND 23 UTC HRRR OUTPUT.
FINALLY...THE WIND ADVISORY FOR THE LIVINGSTON AREA IS WORKING OUT
WELL WITH OBSERVED GUSTS TO 68 MPH ALREADY THIS EVENING. WE ALMOST
ADDED THE NYE AREA INTO THE ADVISORY TOO...BUT SPOTTERS THERE HAVE
ONLY HAD GUSTS UNDER 50 MPH AS 03 UTC...SO WE LEFT THEM OUT OF THE
HEADLINE FOR NOW. WE DID INCREASE FORECAST GUSTS TO 70 MPH TONIGHT
IN THE LIVINGSTON AREA THOUGH TO MATCH OBSERVED TRENDS. SCHULTZ
&&
.SHORT TERM...VALID FOR TUE AND WED...
UNSETTLED CONDITIONS FOR THE NEXT FEW DAYS WITH THE POTENTIAL FOR
A MESSY WINTRY MIX OF PRECIPITATION FOR NEW YEARS EVE AFTERNOON
AND NEW YEARS MORNING.
WIND ADVISORY CONTINUES FOR THE LIVINGSTON AREA THROUGH TONIGHT
AND NO CHANGES MADE TO THIS HIGHLITE. WINDS HAVE BEEN GUSTING
AROUND 50 MPH THIS AFTERNOON AT KLVM AND SHOULD CONTINUE TO
STRENGTHEN THIS EVENING. WINDS WILL DIMINISH TUESDAY
AFTERNOON/EVENING AS A DISTURBANCE MOVES THROUGH WEAKENING THE
SURFACE PRESSURE GRADIENT.
TONIGHT...COLD FRONT HAS SAGGED SOUTHWARD ACROSS SOUTHEAST MONTANA
THIS AFTERNOON AND IS LOCATED FROM LEWISTOWN TO JUST EAST OF
BILLINGS AND SHERIDAN AT 2 PM. WARM ADVECTION WILL KICK IN
OVERNIGHT AS WESTERLY WINDS STRENGTHEN AHEAD OF SYSTEM JUST MOVING
ON SHORE IN THE PACIFIC NORTHWEST. THIS WARM ADVECTION WILL
GENERATE AN AREA OF SNOW FROM ROSEBUD COUNTY EAST OVERNIGHT WITH
THE HEAVIEST SNOW ACCUMULATIONS OF AN INCH OR TWO LIKELY CONFINED
TO A MILES CITY TO ALZADA LINE. OVER WESTERN ZONES STRONG PACIFIC
MOISTURE FETCH WILL MOVE OVER THE AREA PRODUCING SNOW OVER AREA
MOUNTAINS. COULD SEE SEVERAL INCHES OF SNOW OVERNIGHT ABOVE 6000
FEET...WITH HEAVIEST ACCUMULATIONS ON NORTHWEST FACING SLOPES.
SOME OF THIS MOISTURE MAY BE ABLE TO MAKE IT INTO THE LOWER
ELEVATIONS OVERNIGHT SO KEPT LOW POPS IN FROM BILLINGS WEST TO
COVER THIS...BUT NO ACCUMULATIONS EXPECTED. TEMPERATURES WILL HOLD
PRETTY CLOSE TO AFTERNOON READINGS OVER CENTRAL AND WESTERN ZONES
TONIGHT...WHILE EASTERN AREAS WILL SEE SLOWLY RISING TEMPERATURES
AS WARM ADVECTION KICKS IN.
TOMORROW AND TOMORROW NIGHT...COMPLICATED FORECAST FOR THIS TIME
PERIOD DUE TO SEVERAL FACTORS. ARCTIC AIR REMAIN IN PLACE OVER THE
DAKOTAS AND GETS PULLED TO THE WEST TUESDAY AFTERNOON AS A JET
STREAK AND DISTURBANCE CROSS THE AREA. AT THE SAME TIME AN AREA OF
MODERATE QG FORCING PUSHES OVER WESTERN AND CENTRAL ZONES TUESDAY
AFTERNOON AND EVENING. WESTERN AREAS WILL CONTINUE TO SEE
DOWNSLOPE WINDS WHICH WILL WORK TO INHIBIT PRECIPITATION
DEVELOPMENT UNDER THE QG FORCING...BUT THE STRONG MOISTURE
ADVECTION LOOKS SIMILAR TO THE MOISTURE FETCH THAT BROUGHT RAIN TO
THE AREA LAST WEEK. TO TOP IT OFF THE GFS/ECMWF DONT AGREE WITH
THE NAM/SREF ON WHERE TO PUT BEST FORCING OR THE COLD FRONT. SO
THIS IS A DYNAMIC SYSTEM AND DO THINK WE WILL SEE A MIX OF RAIN
AND SNOW WEST OF ROSEBUD COUNTY...WITH ALL SNOW TO THE EAST OF
THERE...BUT HOW MUCH SNOW AND EXACTLY WHERE A PROJECTED BAND OF 2
TO 4 INCHES FALLS IS STILL VERY UNCERTAIN. ALSO...ANY RAIN OR
RAIN/SNOW MIX THAT FALLS TUESDAY AFTERNOON WILL MAKE ROADS WET
WHICH WILL THEN FREEZE UP AS THE COLDER AIR TO THE EAST MOVES
WESTWARD IN THE EVENING CREATING VERY POOR DRIVING CONDITIONS.
FOR NOW HAVE ELECTED TO HOLD OFF ON ISSUING A WINTER WEATHER
ADVISORY DUE TO THE CONTINUED UNCERTAINTY IN PRECIPITATION TYPE
AND POSITION. HOPEFULLY THE 00Z MODEL RUNS COME IN BETTER FOCUS.
HOWEVER CONFIDENT IN THERE BEING PRECIPITATION ACROSS THE AREA.
THE FOCUS OF THE POTENTIALLY WORST CONDITIONS IS IN A BAND FROM
MUSSELSHELL TO SHERIDAN COUNTY AND EAST TO ROSEBUD COUNTY
INCLUDING BILLINGS...AND DID BUMP UP POPS AND SNOW ACCUMULATIONS
TO AROUND 2 INCHES THIS AREA. THERE COULD BE HIGHER ACCUMULATIONS
IN THIS AREA BUT IF PRECIPITATION STAYS LIQUID INTO THE EVENING
ACCUMULATIONS COULD BE LESS THAN AN INCH. ICY ROADS AND TRAVEL
CONCERNS FOR NEW YEARS EVE WILL BE PRESENT FOR MUCH OF THE AREA
GIVEN WIDESPREAD PRECIPITATION.
MOUNTAIN LOCATIONS WILL SEE PERIODS OF HEAVY SNOW RESULTING IN 6
TO 12 INCHES OF ACCUMULATION TUESDAY INTO EARLY WEDNESDAY MORNING.
IT DOES NOT LOOK LIKE A WARNING WILL BE NEEDED FOR AREA MOUNTAINS
AT THIS TIME BUT WILL CONTINUE TO MONITOR THE SITUATION. THE BIG
HORN MOUNTAINS WILL LIKELY NEED AN ADVISORY AND MID SHIFT CAN
INCLUDE THIS WITH OTHER HIGHLIGHTS IF NEEDED ONCE THE 00Z MODEL
RUNS ARE EVALUATED.
NEW YEARS DAY WILL SEE IMPROVEMENT FROM MORNING INTO THE AFTERNOON
AS THE DISTURBANCE PULLS OUT OF THE AREA AND COLDER AIR SLOSHES
BACK TO THE EAST. LIGHT SNOW WILL CONTINUE OVER AREAS FROM ROSEBUD
COUNTY EAST INTO THE AFTERNOON WITH THE SUN COMING OUT OVER
WESTERN AREAS. WILL SEE WINDS INCREASING AGAIN OVER WESTERN
VALLEYS BY WEDNESDAY NIGHT. CHAMBERS
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
MINIMAL CHANGES TO THE EXTENDED FORECAST PERIOD TODAY.
SOME WEAK RIDGING IS IN CONTROL OVER THE REGION TO STATE THE
PERIOD THURSDAY THROUGH THURSDAY NIGHT. TEMPS WILL CLIMB INTO THE
20S EAST AND 40S WEST FOR THURSDAY.
A LONG WAVE TROF MOVES INTO THE REGION FRIDAY. TRENDED POPS
UPWARD SLIGHTLY...AS SYSTEM SYSTEM APPEARS PRETTY CONSISTENT.
TIMING IS STILL A BIT OF AN ISSUE...SO DID NOT ADJUST TEMPS AT
THIS TIME...AS WILL DEPEND GREATLY ON PROGRESSION OF THE SYSTEM
INTO THE AREA. THIS SYSTEM LOOKS LIKE IT COULD LINGER SOME POPS IN
THE EAST INTO SATURDAY MORNING.
GREATEST CONCERN AT THIS TIME FOR THE EXTENDED PERIOD REMAINS THE
ARCTIC PUSH TO END THE WEEKEND AND START THE WORKWEEK. CONSISTENCY
IS GOOD...ALTHOUGH INDIVIDUAL MODELS HAVE JUMPED AROUND A BIT.
CURRENT SNOW COVER IS PRETTY GOOD IN THE EAST...WITH MORE SNOW
EXPECT OVER NEXT COUPLE OF DAYS...AND A BIT MORE LATER THIS WEEK.
THEREFORE WOULD EXPECT LITTLE MODIFICATION OF THE AIRMASS...SO
TRENDED TEMPS COLDER FOR SUNDAY NIGHT AND MONDAY...EVEN THOUGH IS
LATE IN THE PERIOD. ALSO TRENDED POPS UP SLIGHTLY...WITH A BIT
MORE SIGNIFICANT BUMP TO FOOTHILLS REGIONS. MODELS DIFFER
SIGNIFICANTLY ON DURATION OF COLD SNAP...BUT AGREE WELL ON COLD
AIR INTO THE REGION. AAG
&&
.AVIATION...
STRONG W TO SW WINDS IN AND AROUND KLVM...WITH GUSTS OVER 50
KNOTS...EXPECTED TO CONTINUE INTO TUESDAY MORNING. RAIN SHOWERS
AND SNOW BEGIN TO OVERSPREAD THE REGION OVERNIGHT. BEST POTENTIAL
FOR IFR CONDITIONS IN SNOW AND LOW CEILINGS IS OVER THE WESTERN
MOUNTAINS AND FROM KMLS E AND SE AFTER 06Z. THERE MAY ALSO BE A
FEW AREAS OF ICE PELLETS OR FREEZING RAIN EXTENDING FROM HYSHAM
AND FORSYTH SE TOWARDS BROADUS OVERNIGHT. STC
&&
.PRELIMINARY POINT TEMP/POPS...
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 032/039 021/032 021/040 028/045 022/029 013/019 905/000
28/O 83/S 10/U 02/W 31/B 24/J 33/J
LVM 034/040 023/032 027/044 035/045 025/029 012/023 000/011
36/O 62/S 11/N 02/W 32/J 23/J 32/J
HDN 022/036 014/030 014/034 018/043 016/026 006/020 909/000
38/O 84/S 10/U 02/J 41/E 23/J 33/J
MLS 010/019 004/020 008/026 019/041 015/024 004/012 916/907
+7/S 44/S 10/B 02/W 41/E 23/J 22/J
4BQ 017/034 010/026 007/032 018/043 017/025 007/019 912/901
66/S 64/S 10/B 01/B 42/J 23/J 22/J
BHK 003/015 901/013 902/024 015/039 013/021 001/011 920/909
+8/S 53/S 11/B 01/B 42/J 22/J 22/J
SHR 022/039 017/030 013/040 020/046 018/027 008/022 908/004
28/O 83/S 10/U 01/B 42/J 24/J 33/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT UNTIL 5 PM MST TUESDAY FOR ZONE 65.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1133 PM CST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 337 PM CST SAT DEC 28 2013
...A BRIEF BUT POTENT BLAST OF ARCTIC AIR AS TEMPS PLUNGE FROM
TODAY/S NEAR RECORD WARMTH...
ALOFT: PROGRESSIVE NW REMAINS IN PLACE. AN EMBEDDED POSITIVE-TILT
TROF WAS OVER THE NRN ROCKIES. THIS TROF WILL MOVE THRU HERE
TOMORROW...WITH NW FLOW TO FOLLOW.
SURFACE: LOW PRES HAS BEEN MIGRATING E ALONG AN ARCTIC COLD
FRONT...OUT OF THE DAKOTAS FROM THIS MORNING AND WAS OVER SWRN MN
AT 20Z. THE FRONT WAS SURGING S IN ITS WAKE AND IR SATELLITE
IMAGERY SUGGESTS THAT IT/S THRU THE SANDHILLS AND EXTENDS FROM
ALBION-LOUP CITY-LEXINGTON AT 20Z. THE FRONT SHOULD BE THRU THE
FCST AREA IN 6 HRS OR LESS...EXITING INTO CNTRL KS BY 9PM. STRONG
ARCTIC HIGH PRES BUILDS IN TONIGHT AS IT SLIDES INTO THE NRN
PLAINS. IT WILL WEAKEN TOMORROW AS IT CONTINUES DOWN THE MO RIVER
VALLEY.
UPDATED ADVISORY/HAZARDOUS WX OUTLOOK HAVE POSTED. GOSPER/DAWSON/
PHELPS COUNTIES ARE NOW INCLUDED. THE END TIME HAS ALSO BEEN MOVED
UP TO 3 AM...BUT ADVISORY COULD END UP BEING TERMINATED AS EARLY
AS 12 AM.
REST OF THIS AFTERNOON: WE PUT THE FINISHING TOUCHES ON ANOTHER
VERY NICE DAY FOR LATE DEC WITH NEAR-RECORD MUCH ABOVE NORMAL
WARMTH.
A CHECK OF GRI ASOS AT 335 PM VIA MODEM SHOWS A HIGH OF 62F. THE
FRONT HAS MOVED THRU AND THE TEMP IS DOWN TO 59F. CAME WITHIN 2F
OF TYING THE RECORD HIGH /64 IN 2002/.
WE HAVE BEEN WATCHING IMPRESSIVE PRES GRADIENT OVER ND/SD/MT/WY
TODAY WITH EQUALLY IMPRESSIVE WINDS. PEAK GUSTS OF 45-52 KTS HAVE
BEEN COMMON. THERE IS A CORE OF 40-55 KT WINDS AT 850 MB
COINCIDENT WITH THESE WINDS. THE RAPID CITY 88D CONFIRMS ITS
PRESENCE.
EXPECT DOWNWARD TRANSFER IN VERY STEEP LAPSE RATES/COLD AIR
ADVECTION AS THIS JET CORE DROPS INTO THE FCST AREA.
THE STRONGEST WINDS WILL OCCUR IN THE 6-8 HRS IMMEDIATELY
FOLLOWING PASSAGE OF THE COLD FRONT /IE BEFORE MIDNIGHT/.
VALENTINE HAD A PEAK WIND OF 45 KTS AT 218 PM.
THE WINDIEST LOCATIONS WILL BE ALONG AND N OF HWY 92. RAP TIME-
HEIGHT CROSS SECTIONS SHOW 45 KTS DOWN TO 1K FT WITH A CORE OF 50
KTS DOWN TO 1800 FT FROM 9PM-12AM. 18Z NAM HAS 52 KTS BUT ONLY AS
LOW AS 2K FT 6PM-9PM. BOTTOM LINE...WOULD NOT BE SURPRISED TO SEE
G50-55 MPH IN THESE AREAS THIS EVE.
15Z SREF PROBABILITIES FOR MEAN WINDS 30 MPH OR GREATER ARE
HIGHEST OVER CNTRL NEB N INTO THE SANDHILLS 6PM-11PM. THIS IS
WHERE THE ADVISORY HAS THE BEST CHANCE OF VERIFYING.
TONIGHT: WINDY AND TURNING MUCH COLDER. BECOMING MOSTLY CLOUDY AS
THE 900-850 MB LAYER COOLS TO SATURATION. EXTENSIVE MID-HIGH
CLOUDS WILL ALSO INVADE. LOW TEMPS ROUGHLY 8F COLDER THAN NORMAL.
TOMORROW: DECREASING CLOUDS AND WINDS. TEMPS MUCH COLDER THAN
NORMAL /BY 15-20F/.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 332 PM CST SAT DEC 28 2013
A 1035MB SURFACE HIGH PRESSURE SYSTEM WILL BUILD SOUTH ALONG THE
MISSOURI RIVER SUNDAY EVENING...AND EXPECT TEMPERATURES WILL DROP
OFF RATHER QUICKLY FOR THE FIRST PART OF THE NIGHT. AS THE SFC
RIDGE AXIS WEAKENS AND SHIFTS EASTWARD SUNDAY NIGHT...RETURN FLOW
SETS UP AND THE AIRMASS BEGINS TO MODERATE AND TEMPERATURES SHOULD
TREND UP HEADING INTO MONDAY MORNING.
THE UPPER TROUGH AXIS WILL TRANSLATE EAST/NORTHEASTWARD FOR THE
FIRST PART OF THE WEEK...WHICH ALLOWS FOR A REBOUND IN
TEMPERATURES FOR OUR AREA AS HEIGHTS RISE BEHIND THE SYSTEM. THIS
BEING SAID IT IS IMPORTANT TO NOTE THAT THE COLD AIR IS NOT THAT
FAR AWAY AND IF THE BAROCLINIC ZONE SHIFTS FARTHER SOUTH AND
WEST...IT WILL BE ACROSS US AND TEMPS WILL BE COLDER. THE BIGGEST
CHANGE IN THE FORECAST COMES IN THE TUESDAY TIME FRAME AS SEVERAL
OF THE LATEST OPERATIONAL MODELS NO LONGER BACK A COLD FRONT AS
FAR SOUTH INTO SC NEBRASKA AS PREVIOUS RUNS. MODELS ARE IN PRETTY
GOOD AGREEMENT THAT THE COLD AIR AND STRATUS WILL BE ORIENTED
ACROSS SOUTH DAKOTA/NORTHERN IOWA AND PERHAPS FAR NORTHERN
NEBRASKA THROUGH THE DAY...ALTHOUGH A COLD FRONT DOES ADVANCE
SOUTH IN THE AFTN. HAVE RAISED TEMPERATURES FOR TUESDAY...BUT WILL
NEED TO MONITOR THERMAL AND CLOUD FIELDS CLOSELY AS THE 12Z ECMWF
REMAINS COLDER THAN GFS/GEM/NAM IN THIS TIME FRAME.
A COLD FRONT PUSHES SOUTH TUESDAY/NEW YEARS EVE NIGHT AND MODELS
ARE NOT OVERLY ROBUST IN GENERATING PCPN WITH THIS BUT DID
MAINTAIN SOME VERY LOW POPS FOR LIGHT SNOW ACROSS OUR NORTHEAST
ZONES. LIGHT WINTRY PCPN IS POSSIBLE ON WEDNESDAY/NEW YEARS DAY AS
A 120KT JET NOSES SOUTH ALONG THE ROCKIES/HIGH PLAINS REGION AND
DEEPENS A TROUGH ACROSS THE PLAINS AND UPPER MIDWEST. COLDER AIR
ADVECTS SOUTH AND A BAND OF FRONTOGENETIC SNOWFALL IS POSSIBLE
INTO WEDNESDAY NIGHT.
THURSDAY WILL BE THE TRANSITION DAY BETWEEN THE COLD AIR AT THE
MIDDLE OF THE WEEK AND A WARMING TREND FOR THE END OF THE WEEK.
THE UPPER TROUGH AND COLD AIR ONCE AGAIN SLIDE EAST THURSDAY WITH
HEIGHTS RISING/MODERATING TEMPS IN ITS WAKE. FRIDAY IS SHAPING UP
TO BE MILD AGAIN WITH ABOVE NORMAL TEMPS IN SUBTLE RIDGING ALOFT.
SATURDAY TEMPS WILL BE DEPENDENT ON COLD FRONTAL TIMING WITH THE
GFS QUICKER WITH THE FRONT PASSAGE THAN THE ECMWF...AND GIVEN
MODEL DIFFERENCES DID NOT DEVIATE MUCH FROM INIT FOR DAY 7.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1125 PM CST SAT DEC 28 2013
MVFR CIGS WILL CONTINUE TO STREAM ACROSS THE TERMINAL THROUGH THE
OVERNIGHT HOURS WITH A FEW BRIEF LIGHT FLURRIES ALSO POSSIBLE. IN
ADDITION...EXPECT STRONG NORTHERLY WINDS TO CONTINUE...
OCCASIONALLY GUSTING TO NEAR 40 KTS...THROUGH ABOUT 29/12.
THEREAFTER...EXPECT THE PRESSURE GRADIENT TO BEGIN TO
WEAKEN...AND WINDS TO DIMINISH SLOWLY THROUGH THE DAY...
EVENTUALLY BECOMING LIGHT AND VARIABLE BY LATE AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ039>041-046>049-
060>064-072>077.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...FAY
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1128 PM CST SAT DEC 28 2013
.UPDATE...
ISSUED AT 1118 PM CST SAT DEC 28 2013
SURFACE WINDS CONTINUE TO DECREASE ACROSS THE WEST WITH THE WIND
ADVISORY FOR AREAS WEST OF HIGHWAY 83 TO EXPIRE AT MIDNIGHT. THEN
MAIN CONCERN WILL BE THE SURFACE WINDS OVER THE NORTH CENTRAL
THROUGH 3 AM AND HOW LOW TEMPERATURES WILL GO BY DAYBREAK.
SATELLITE SHOWS CLOUD TOPS WARMING WITH CLEARING TO INFLUENCE HOW
LOW TEMPERATURES WILL GO WITH NEW GUIDANCE SHOWING ANOTHER 2 TO 3
DEGREES COLDER ACROSS THE NORTH. FOR NOW NO BIG CHANGES AS THE COMBINATION
OF COLDER AIR AND WINDS WILL DRIVE WIND CHILL VALUES DOWN. PLEASE REFER
TO WIND CHILL ADVISORY FOR DETAILS.
UPDATE ISSUED AT 918 PM CST SAT DEC 28 2013
SURFACE WINDS DIMINISHING ACROSS THE PANHANDLE AND SOUTHWEST TO
CANCEL THE WIND ADVISORY FOR AREAS GENERALLY WEST OF A LINE FROM
KILGORE TO MULLEN...TRYON..AND BRADY. FURTHER EAST STRONG WINDS
WILL LINGER A FEW MORE HOURS THEN DIMINISH ACROSS THE NORTH
CENTRAL EARLY MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 706 PM CST SAT DEC 28 2013
FORECAST UPDATED AS SNOW SHOWERS A LITTLE MORE AGRESSIVE AND
FURTHER SOUTH. THE SNOW SHOWERS ARE MOVING SOUTH AROUND 25 MPH
WITH LOW POPS INTRODUCED THROUGHOUT THROUGH MIDNIGHT AND TRENDED
TO THE LATEST RUC SOLUTION. NO ACCUMULATIONS EXPECTED ALTHOUGH
VISIBILITY MAY BE BRIEFLY REDUCED AS SNOW SHOWERS MOVE ACROSS
THROUGH MIDNIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 331 PM CST SAT DEC 28 2013
A PROGRESSIVE PATTERN CONTINUES IN THE NORTHWEST FLOW ACROSS THE
PLAINS THROUGH MOST OF NEXT WEEK.
THE NEXT STORM SYSTEM FROM THE CANADIAN ROCKIES COMES THROUGH
WESTERN NEBRASKA TUESDAY. THERE IS SOME ISENTROPIC LIFT INDICATED IN
THE 290-300K LAYER...BUT MOISTURE IS LACKING EVERYWHERE EXCEPT THE
AREA NORTH AND WEST OF ONEILL.
ANOTHER PULSE IS ON THE WAY FOR TUESDAY NIGHT THROUGH WEDNESDAY.
THAT ONE ALSO SHOWS ISENTROPIC LIFT IN THE 290-300K LAYER WITH SOME
FRONTOGENETIC ENHANCEMENT IN CENTRAL AND NORTH CENTRAL NEBRASKA.
THOUGH MOISTURE IS A LITTLE BETTER...IT IS STILL FAIRLY DRY IN THE
LOWER LAYERS. ALSO...THERE ARE SIGNIFICANT DIFFERENCES IN THE
LOCATIONS INDICATED IN THE THREE MEDIUM/LONG RANGE MODELS (THE
ECMWF...GEMNH AND US GFS)...SO WE WILL KEEP THE PROBABILITY LOW FOR
NOW.
ANOTHER SYSTEM IS EXPECTED TO DEVELOP IN COLORADO FRIDAY OR
SATURDAY...BUT THE UNCERTAINTY WITH THAT ONE IS HIGH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1125 PM CST SAT DEC 28 2013
MARGINAL VISUAL FLIGHT RULES CONTINUE OVERNIGHT AT THE KVTN AND
KLBF TERMINALS. SATELLITE SHOWS CLOUD TOPS WARMING ACROSS THE
NORTHWEST WITH CEILING LIFTING BEYOND 12Z FOR VISUAL FLIGHT RULES
AT KLBF AND KVTN BEYOND 15Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 3 AM CST /2 AM MST/ TO 9 AM CST /8 AM
MST/ SUNDAY FOR NEZ004>010-023>029-094.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ007-010-027>029-038.
WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NEZ005-006-008-009-
025-026-037.
&&
$$
UPDATE...KECK
SHORT TERM...KECK
LONG TERM...SPRINGER
AVIATION...KECK
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1020 PM EST MON DEC 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL BRING PARTLY CLOUDY SKIES AND COLD TEMPERATURES
TO THE REGION TONIGHT. WEAK LOW PRESSURE TRACKING ACROSS LOWER
ONTARIO WILL BRING SOME LIGHT SNOW TO THE AREA ON TUESDAY...WITH
LAKE EFFECT SNOWS DEVELOPING BEHIND THIS SYSTEM FOR TUESDAY NIGHT
AND WEDNESDAY MORNING. MORE WIDESPREAD SNOW IS EXPECTED TO DEVELOP
ON WEDNESDAY NIGHT AND THURSDAY...WITH THE POTENTIAL FOR MODERATE
ACCUMULATIONS.
&&
.NEAR TERM /THROUGH TUESDAY/...
LAKE EFFECT MOISTURE CONTS TO LINGER IN THE CENTRAL SOUTHERN TIER
OF NY AND NC PA. THERE LOOKS LIKE THERE WAS EVEN FINGER LAKES
MOISTURE GETTING DRAWN IN AS WELL. CONTINUING SUBSC AND WEAKENING
WINDS OVERNIGHT SHUD CUT OFF ALL THE LAKE EFFECT FLURRIES. BY 6Z
THE LATEST RAP MODEL HAS 925 MB WINDS GOING CALM SO HAVE FLURRIES
ENDING AT THIS TIME. OTHERWISE CLOUDS WILL STREAM IN OVERHEAD AS
UVV INCREASES AHEAD OF NEXT SMALL CLIPPER SYSTEM. ALL SYNOPTIC
MODELS SHOW THIS SYSTEM WORKING ACRS NY AND PA TUESDAY DURING THE
DAY. THE MAIN DYNAMICAL FEATURE ASSCTD WITH THIS WAVE WAS JET
STREAK WHICH WAS DROPPING INTO THE BASE OF THE UPPER TROF OVER THE
ERN LAKES BY 18Z TUE. NRN PA AND C NY ARE IN THE LEFT FRONT QUAD
OF THIS UPPER LEVEL JET AND THERE WAS SIGNIFICANT LIFTG.
HOWEVER...TYPICAL OF NRN BRANCH WAVES THERE WAS LITTLE MOISTURE.
SO NOT LOOKING AT MUCH SNOW ACC/S...MAYBE AN INCH AT BEST. MODELS
AGREE THAT LIGHT SNOW ARRIVES FROM W TO E BWTN 10 AND 13Z AND
EXITS IN THE AFTERNOON. AFTER THIS WAVE PASSES BY A COLD STRONG
WESTERLY FLOW OF AIR SETS UP IN THE LOW-LEVELS TRIGGERING MORE
LAKE EFFECT SNOWS. H85 TEMPS DROP TO -18C OR SO WITH DECENT
INSTABILITY. KEPT LES WATCH GOING FOR NRN ONEIDA CO AS EXACT PLACEMENT
OF THE LAKE ONTARIO SNOWBAND STILL IS UNCERTAIN. IN ADDTN...925 MB
AND 850 MB WINDS ARE QUITE STRG RUNNING OVER 30 KNOTS...MESOSCALE
AND EVEN SYNOPTIC MODELS ARE HINTING AT A LAKE ERIE BAND THAT CUD
EXTEND WELL INLAND ACRS THE SRN TIER OF NY AND INTO NE PA. I HAVE
CHC POPS FOR SNOW SHOWERS IN THESE AREAS TO COVER THIS BEGINNING
TUE PM.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
LES BAND SHUD BE GOING STRONG TMRW EVNG ACRS NRN SXNS OF THE FCST
AREA. PROFILES ARE PRETTY IMPRSV WITH HIGH INVERSION LVL AND GOOD
SIGS FOR SNOW GROWTH. UNCERTAINTY AS TO HOW FAR SOUTH THIS BAND
WILL GET...WITH SOME MDLS KEEPING ACTIVITY OVER FAR NRN ZONES OF
THE BGM CWA...WHILE OTHERS DROP THE BAND SEWD INTO ONON/MAD/SRN
ONEIDA. FOR NOW ISSUED THE LES WATCH FOR NRN ONEIDA WHERE OUR
CONFIDENCE IS GREATEST...AND MENTIONED THE POTENTIAL (IF THE BAND
DROPS SOUTH) IN THE HWO FOR THE AFOREMENTIONED COUNTIES.
OPERATIONAL MDLS ARE TRENDING SLOWER AND DEEPER WITH THE UPR LVL
TROF DIGGING INTO THE ERN U.S. ON THURSDAY...AND ISENTROPIC LIFT
DVLPNG N OF THE ARCTIC FNTL BNDRY. STRONG HIGH PRES OVER QUEBEC
WILL KEEP THE COLD AIR LOCKED IN PLACE. A RATHER PROLONGED PD OF
SNOW LOOKS LIKELY TO BEGIN ON WED AND CONTINUE INTO THU...PRBLY INCRSNG
IN INTENSITY ON THU. NICE SIGS IN THE QVEC AND FGEN FIELDS...WITH
PROFILES LOOKING GOOD FOR SNOW GROWTH. SNOW RATIOS SHUD ALSO BE
RATHER HIGH GIVEN THE COLD AIR MASS. AT THIS POINT WILL CONTINUE
TO MENTION POTNL IN THE HWO.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
3 PM MON UPDATE... SYNOPTIC SNOWFALL EVENT SHOULD BE ONGOING THU
NGT...PERHAPS LINGERING INTO FRI. THERE ARE STILL PLENTY OF MODEL
DISCREPANCIES WITH THIS STORM...AS THE 12Z EC REMAINS THE MOST
AMPLIFIED AND SLOWEST WITH THE MAIN UPPER-LVL TROUGH AXIS...WHILE
THE GFS/CAN GEM ARE MORE PROGRESSIVE. ATTM...WPC IS LEANING TWDS
THE MORE PROGRESSIVE SOLNS...GIVEN THE PROGGED CANADIAN MARITIME
UPPER-LVL LOW...AND THE CONFLUENT PATN UNDERNEATH IT...WHICH SEEMS
REASONABLE AT THIS EARLY VANTAGE PT. EVEN SO...NICE WAA/FGEN FORCING
INTO THU NGT...FOLLOWED BY BRIEF DEFORMATION BAND MECHANICS INTO
EARLY FRI...LIKELY TRANSLATES TO AT LEAST WIDESPREAD ADVSY LVL
SNOW ACCUMS. STAY TUNED...AS MANY DETAILS ARE YET BE IRONED OUT.
THE OTHER MAIN STORY THIS PD IS THE ARCTIC AMS EXPECTED TO PLUNGE
SWD INTO CNY/NE PA FRI INTO SAT. IF ANYTHING...THE MODELS HAVE
TRENDED EVEN COLDER IN RECENT RUNS...WITH BOTH THE GFS/EC SHOWING
TEMPS NOT MUCH ABV ZERO FRI...THEN WELL BLO ZERO FRI NGT/EARLY
SAT. WE`VE BEEN ADVERTISING SINGLE DIGIT HIGHS ON FRI...WITH WELL
BLO ZERO READINGS FRI NGT/SAT MRNG...SO WE DIDN`T MAKE MANY CHGS
HERE. WE DID NUDGE TEMPS LWR LTR IN THE WEEKEND INTO EARLY NEXT
WEEK...TO BETTER MATCH THE LATEST STATISTICAL GUIDANCE.
MAINLY DRY WX IS STILL FORESEEN AT THE BEGINNING OF THE
WEEKEND...WHEN THE DEEPEST COLD WILL LIKELY BE IN PLACE. FROM SUN
INTO EARLY NEXT WEEK...ADDITIONAL NRN STREAM SHRT WV/FRNTL
PASSAGES ARE LIKELY...SO WE`VE JUST GONE WITH A GENERIC CHC OF
SHSN/FLRYS FOR NOW. AS WE DRAW CLOSER IN TIME...HOPEFULLY WE`LL
GET A BETTER FEEL FOR WHERE THE MOST PERSISTENT LES BANDS MAY SET
UP.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
00Z UPDATE...
LINGERING LAKE EFFECT SNOW SHOWERS MAY BRING MVFR AND OCNL IFR
CONDITIONS TO KSYR AND KITH TONIGHT THROUGH 04Z, OTHERWISE VFR
CONDITIONS EXPECTED. LOW PRESSURE SYSTEM WILL BRING THE NEXT
CHANCE FOR MVFR/IFR SNOW TO THE AREA AFTER 14Z TOMORROW AND SHOULD
MOVE OUT AROUND 21Z. AFTER THE SNOW EXITS TO THE EAST EXPECT
KITH/KELM/KBGM AND KAVP TO BECOME VFR, WITH KSYR AND KRME
REMAINING MVFR IN LAKE EFFECT SNOW SHOWERS THROUGH END OF TAF
VALID TIME.
WINDS WILL BE LIGHT OUT OF THE NORTH EARLY THEN BECOME LGT/VRB
UNDER HIGH PRESSURE OVERNIGHT. SOUTHERLY WINDS AROUND 10KTS
EXPECTED AFTER 12Z TUESDAY BECOMING WESTERLY BEHIND SYSTEM
15G25KTS.
OUTLOOK...
TUE NGT/WED...MVFR/IFR SHSN IN KSYR/KRME...WITH MAINLY VFR ELSEWHERE.
WED NGT-THU NGT...IFR SNOW LIKELY AREA-WIDE.
FRI...LINGERING RESTRICTIONS PSBL IN SHSN.
FRI NGT/SAT...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW WATCH FROM TUESDAY AFTERNOON THROUGH
WEDNESDAY MORNING FOR NYZ009.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...
LONG TERM...MLJ
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BUFFALO NY
951 AM EST SUN DEC 29 2013
.SYNOPSIS...
LOW PRESSURE MOVING UP THE EAST COAST WILL BRING SOME RAIN TO OUR
AREA THIS AFTERNOON. THE RAIN COULD MIX WITH SNOW ACROSS THE HIGHER
ELEVATIONS OF THE SOUTHERN TIER. AS THE LOW PULLS AWAY FROM THE NEW
ENGLAND COAST TONIGHT...A NORTHWEST OF MUCH COLDER AIR WILL SURGE
ACROSS THE LOWER LAKES AND GENERATE SOME LAKE EFFECT SNOW SHOWERS.
ANOTHER LOW WILL BRING A GENERAL SNOWFALL...AND SOME LAKE ENHANCED
SNOW...LATE MONDAY NIGHT INTO TUESDAY. VERY COLD AIR THAT FOLLOWS
THIS LOW WILL LAST THROUGH THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 930 AM...RADAR SHOWS PRECIPITATION SPREADING INTO NORTHERN
PENNSYLVANIA...WITH THIS LIKELY TO REACH THE NY BORDER IN THE
NEXT HOUR. THIS AREA WILL CONTINUE TO SPREAD NORTHWARD THROUGH
MID-AFTERNOON...AND THEN START RETREATING TO THE EAST LATE
AFTERNOON. THE 12Z NAM AND RUNS OF THE HRRR SHOW ONLY A MODEST
SHIFT IN GUIDANCE. THE BIGGEST DIFFERENCE IS THAT THE WESTERN CUT-
OFF OF THE PRECIPITATION SHOULD BE JUST SLIGHTLY TO THE
EAST...WHICH INCREASES THE CHANCE BUFFALO AND AREAS NORTH AND WEST
WILL STAY DRY TODAY. IN FACT...THE BACK EDGE OF THE PRECIPITATION
SHIELD WILL LIKELY BE NEAR A BUF-ART LINE...HOWEVER STILL MAINTAIN
A HIGH CONFIDENCE IN MEASURABLE PRECIPITATION SE OF THIS WHICH
INCLUDES THE VAST MAJORITY OF THE CWA.
THE MODELS AGREE THAT THIS LOW WILL STRENGTHEN AS IT LIFTS
NORTHEAST AND REACHES THE VICINITY OF LONG ISLAND BY THIS EVENING.
THIS PROJECTED PATH OF THE LOW NORMALLY DOES NOT BRING MUCH
PRECIPITATION TO OUR REGION. AND THIS WILL LIKELY BE THE CASE
TODAY WITH THE MAIN LIFT ASSOCIATED WITH THE POTENT LOW LEVEL
EXPECTED TO STAY ALONG THE EAST COAST. HOWEVER...A BROAD SCALE
CYCLONIC FLOW WILL BE IN PLACE OVER NEW YORK STATE...WHILE A
PASSING UPPER LEVEL JET STREAK GENERATES ADDITIONAL LARGE SCALE
LIFT. AS A RESULT...STILL HAVE CONFIDENCE THAT MEASURABLE
PRECIPITATION WILL FALL ACROSS MOST OF THE CWA...EVEN IF IT WILL
BE RELATIVELY LIGHT.
STEADIEST PRECIPITATION WILL BE ACROSS CENTRAL NEW YORK...WITH
BETWEEN TWO AND FOUR TENTHS OF AN INCH OF QPF SOUTHEAST OF ELZ-
FZY. HOWEVER...THERE IS STILL A CONCERN THAT AS THE RAIN BECOME
MORE STEADY ACROSS THE SOUTHERN TIER THIS AFTERNOON...THE HIGHER
ELEVATIONS SHOULD SEE A CHANGEOVER TO SNOW AS THE BOUNDARY LAYER
COOLS FROM EVAPORATIONAL COOLING. THIS WILL RESULT IN AN
ISOTHERMAL LAYER CENTERED AROUND 0C...WITH AN 1 TO 3 INCHES OF WET
SNOW EXPECTED AT ELEVATIONS ABOVE 1600-1800 FEET. A SIMILAR STORY MAY
PLAY OUT ACROSS PORTIONS OF LEWIS COUNTY...AGAIN DEPENDING ON
ELEVATION.
AS THE MAIN LOW PULLS AWAY FROM THE NEW ENGLAND COAST THIS
EVENING...THE ARCTIC FRONT THAT IS ASSOCIATED WITH THE SOUTHERN
QUEBEC LOW WILL PUSH EAST ACROSS WESTERN AND CENTRAL NEW YORK. THIS
WILL CAUSE ANY LINGERING PCPN TO CHANGE OVER TO SNOW. SNOW
ACCUMULATIONS SHOULD BE MINIMAL THIS EVENING SINCE THE STEADIEST
PCPN ASSOCIATED WITH THE DEPARTING LOW WILL BE GONE BY THE TIME THE
COLDER AIR ARRIVES.
A NORTHWEST FLOW OF COLDER AIR WILL SET UP ACROSS THE LOWER LAKES
DURING THE SECOND HALF OF THE NIGHT. THIS WILL RESULT IN SOME LAKE
EFFECT SNOW SOUTHEAST OF THE LAKES. ACCUMULATIONS TONIGHT SHOULD
REMAIN BELOW ADVISORY CRITERIA SINCE THE DEEPER SYNOPTIC MOISTURE
ASSOCIATED WITH THE LOW WILL BE GONE.
REGARDING TEMPERATURES...TODAY`S RELATIVELY MILD READINGS WILL GIVE
WAY TO MUCH COLDER CONDITIONS TONIGHT AS TEMPERATURES FALL INTO THE
TEENS/LOWER 20S BY DAYBREAK MONDAY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
850MB TEMPS DROP TO AROUND -16C BY MONDAY MORNING...PLENTY COLD
ENOUGH TO SUPPORT A LAKE RESPONSE UNDER NW FLOW. THE AIRMASS WILL BE
RAPIDLY DRYING OUT HOWEVER AS SURFACE HIGH PRESSURE AND SUBSIDENCE
QUICKLY BUILDS TOWARDS THE LOWER LAKES. THE DRY BACKGROUND SYNOPTIC
SCALE ENVIRONMENT WILL GREATLY LIMIT THE STRENGTH OF THE LAKE
RESPONSE...WITH JUST LIGHT SNOW SHOWERS EXPECTED SOUTHEAST OF THE
LAKES. THIS MAY PRODUCE AN INCH OR TWO IN SOME SPOTS ALONG THE
CHAUTAUQUA RIDGE OFF LAKE ERIE AND FROM WAYNE TO OSWEGO COUNTIES OFF
LAKE ONTARIO DURING THE MORNING. THE LAKE EFFECT WILL SLOWLY
DIMINISH TO SCATTERED FLURRIES AND LIGHT SNOW SHOWERS BY AFTERNOON.
OUTSIDE OF LAKE EFFECT AREAS ANY LINGERING FLURRIES OR LIGHT SNOW
SHOWERS IN THE MORNING WILL GRADUALLY END WITH SOME BREAKS OF
SUNSHINE DEVELOPING LATER IN THE DAY. HIGHS WILL ONLY BE IN THE
UPPER TEENS IN MOST AREAS...WITH LOWER TEENS ACROSS THE NORTH
COUNTRY.
HIGH PRESSURE BRIEFLY BUILDS OVER THE LOWER LAKES MONDAY EVENING.
THIS WILL BRING AN END TO THE LAKE EFFECT AS ANY SNOW SHOWERS LEFT
WILL RETRACT BACK OVER THE LAKE AND TEA KETTLE AS THE LOW LEVEL FLOW
BECOMES LIGHT AND LAND BREEZE CIRCULATIONS TAKE OVER. LOWS WILL DROP
INTO THE LOWER TEENS OR HIGH SINGLE DIGITS ACROSS WESTERN NY AND A
LITTLE BELOW ZERO EAST OF LAKE ONTARIO. THESE LOWS WILL LIKELY OCCUR
EARLY...WITH INCREASING CLOUDS AND MIXING DEVELOPING LATER AHEAD OF
A FAST MOVING CLIPPER.
THE CLIPPER LOW AND ASSOCIATED MID LEVEL SHORTWAVE WILL PASS BY JUST
NORTH OF THE REGION ON TUESDAY. THIS WILL PRODUCE SOME LIGHT SNOW
ACROSS MOST AREAS WITH AN INITIAL PUSH OF WARM ADVECTION PROVIDING
ISENTROPIC ASCENT...FOLLOWED BY DPVA JUST AHEAD OF THE MID LEVEL
SHORTWAVE SUPPORTING A FEW MORE SNOW SHOWERS. OUTSIDE OF LAKE EFFECT
AREAS AMOUNTS WILL BE LIGHT...WITH A COATING TO AN INCH ACCUMULATION.
THE AIRMASS IS COLD ENOUGH AHEAD OF THE CLIPPER TO SUPPORT A LAKE
RESPONSE...AND INSTABILITY WILL IMPROVE NEAR THE TIME OF THE PASSAGE
OF THE MID LEVEL SHORTWAVE AND SURFACE COLD FRONT. LAKE INDUCED
EQUILIBRIUM LEVELS WILL RISE TO AROUND 10K FEET AT THIS TIME OFF
BOTH LAKES WITH MODERATE INSTABILITY DEVELOPING. BOUNDARY LAYER FLOW
WILL INITIALLY BE SHEARED AHEAD OF THE CLIPPER...BUT NAM AND GFS
BUFKIT PROFILES SHOW WINDS BECOMING BETTER ALIGNED ALONG AND JUST
BEHIND THE SURFACE COLD FRONTAL PASSAGE. PAST EXPERIENCE SHOWS THIS
TYPE OF SYSTEM IS OFTEN ACCOMPANIED BY A BURST OF LAKE ENHANCED SNOW
ALONG THE COLD FRONT OF THE CLIPPER...AND SOME OF THE HIGHER
RESOLUTION MODEL GUIDANCE IS SUGGESTING THAT WITH THIS FEATURE. THIS
MAY PRODUCE SEVERAL INCHES OF ACCUMULATION ACROSS THE NIAGARA
FRONTIER BEFORE PUSHING QUICKLY SOUTH INTO THE SOUTHERN TIER BY THE
END OF THE DAY. A SIMILAR TREND IS EXPECTED EAST OF LAKE ONTARIO A
FEW HOURS LATER.
FOLLOWING THE LAKE ENHANCEMENT WITH THE CLIPPER...EXPECT MORE PURE
LAKE EFFECT TO CONTINUE LATER TUESDAY AFTERNOON AND TUESDAY NIGHT.
BANDS SHOULD REMAIN MOBILE HOWEVER WITH BOUNDARY LAYER FLOW VEERING
TO WEST AND EVENTUALLY NORTHWEST OVERNIGHT AS AN ARCTIC COLD FRONT
SAGS SLOWLY SOUTH ACROSS THE LOWER LAKES. THIS WILL LIKELY FORCE THE
LAKE ONTARIO BAND SOUTH AND ONSHORE ALONG MUCH OF THE SOUTH SHORE
WITH A BURST OF SNOW BEFORE BREAKING APART INTO MULTIPLE WEAK BANDS
LATE BEHIND THE ARCTIC BOUNDARY.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
VERY COLD AIR WILL DOMINATE THE LONG TERM PERIOD WITH THE POTENTIAL
FOR ACCUMULATING SNOW AS WELL LATE THIS WEEK.
THE ARCTIC VORTEX WILL TAKE A SWING ACROSS HUDSON BAY AND INTO
QUEBEC ON WEDNESDAY AND FORCE A VERY COLD AIRMASS SOUTH INTO THE
GREAT LAKES AND NORTHEAST. THE NORTH COUNTRY SHOULD GET INTO THE DRY
ARCTIC AIRMASS BEHIND THIS FRONT ON WEDNESDAY AND REMAIN DRY...WITH
A CHANCE OF A LITTLE LIGHT SNOW ACROSS WESTERN AND CENTRAL NY ALONG
THE BOUNDARY AND DUE TO A LITTLE WEAK NORTHERLY FLOW LAKE EFFECT.
MODEL GUIDANCE HAS MADE SOME SIGNIFICANT ADJUSTMENTS OVER THE PAST
24 HOURS FOR THE THURSDAY AND FRIDAY TIME FRAME. LATEST 00Z GFS AND
ECMWF OPERATIONAL SOLUTIONS ARE MUCH FARTHER NORTH AND DEEPER WITH A
MID LEVEL SHORTWAVE AND SURFACE LOW. IF THIS WERE TO VERIFY IT WOULD
PRODUCE A LONG DURATION ACCUMULATING SNOW WEDNESDAY NIGHT THROUGH
FRIDAY ACROSS THE ENTIRE AREA...WITH LAKE ENHANCEMENT SOUTH OF LAKE
ONTARIO ON THE TAIL END FRIDAY.
THESE SAME OPERATIONAL MODELS YESTERDAY SHOWED THIS SYSTEM
SUPPRESSED WELL SOUTH ACROSS THE SOUTHEAST STATES WITH GENERALLY
COLD AND DRY WEATHER IN OUR REGION. LATEST 00Z GEFS ENSEMBLE MEMBERS
STILL SHOW A WIDE RANGE OF SOLUTIONS...WITH SOME SUPPORT FOR THE
OPERATIONAL GFS AND ECMWF SOLUTIONS...WHILE OTHER MEMBERS SHOW THE
LOWER LAKES DRY WITH A FAR SOUTHERLY SOLUTION. USING THE PRESSURE ON
THE 1.5 PVU SURFACE AS A TRACER...THE ENERGY THAT MAY PRODUCE THIS
SYSTEM IS CURRENTLY JUST SOUTHWEST OF THE ALEUTIAN ISLANDS WHILE
ANOTHER PIECE OF THE PUZZLE IS COMING ACROSS THE TOP OF THE WORLD IN
CROSS POLAR FLOW. GIVEN BOTH OF THESE SYSTEMS ARE SO FAR AWAY AND IN
DATA SPARSE REGIONS... THE CURRENT MODEL SOLUTIONS FOR THURSDAY AND
FRIDAY SHOULD BE CONSIDERED LOW CONFIDENCE EVEN WITH GOOD AGREEMENT
AT THE MOMENT. WITH THIS IN MIND...HAVE JUST INCREASED POPS INTO THE
MID CHANCE RANGE FOR THE PERIOD. IF MODEL GUIDANCE TOMORROW REMAINS
CONSISTENT...MORE CONFIDENCE IN THE SCENARIO WILL EXIST.
TEMPERATURES WILL REMAIN COLD THURSDAY AND FRIDAY REGARDLESS OF
WHETHER THE SYSTEM VERIFIES OR NOT. LOWS WILL AT LEAST BE IN THE
SINGLE NUMBERS WITH HIGHS IN THE TEENS ACROSS MOST OF THE AREA WITH
SOME POTENTIAL FOR EVEN COLDER READINGS. ACROSS THE NORTH COUNTRY
SINGLE DIGIT HIGHS ARE LIKELY WITH LOWS WELL BELOW ZERO. EXACTLY HOW
COLD IT GETS ON SOME OF THESE NIGHTS WILL DEPEND ON THE TRACK AND
TIMING OF SURFACE HIGHS...AND WHETHER SKIES CAN CLEAR OUT OR NOT. IF
THEY DO...TEMPERATURES MAY FREE FALL.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
LOW PRESSURE OVER THE SOUTHEAST STATES WILL MOVE TO THE NORTHEAST
AND REACH LONG ISLAND BY THIS EVENING. LIGHT RAIN DEVELOPING WELL
AHEAD OF THIS SYSTEM WILL MOVE INTO THE SOUTHERN TIER THIS
MORNING...THEN SPREAD NORTH ACROSS THE REST OF THE AREA THIS
AFTERNOON. THE RAIN MAY MIX WITH OR CHANGE TO SNOW ACROSS THE HIGHER
ELEVATIONS OF THE SOUTHERN TIER....BUT SHOULD STAY ALL RAIN AT TAF SITES.
VFR CLOUDS WILL LOWER THROUGHOUT THE MORNING. AS THE RAIN BECOME
MORE WIDESPREAD THIS AFTERNOON...THE LOWER LEVELS WILL
MOISTEN...CAUSING CIGS TO DETERIORATE TO MVFR. WHERE THE RAIN MIXES
WITH SNOW LATER THIS AFTERNOON AND EVENING...IFR CONDITIONS ARE
LIKELY.
AFTER THE LOW PULLS AWAY FROM THE NEW ENGLAND COAST THIS
EVENING...THE STEADIER PCPN WILL TAPER OFF FROM WEST TO EAST. COLDER
AIR FOLLOWING THE LOW WILL CHANGE ANY REMAINING PCPN TO SNOW.
MAINLY MVFR CONDITIONS WILL PREVAIL...EXCEPT EAST AND SOUTHEAST OF
THE LAKES WHERE STEADIER SNOW WILL RESULT IN IFR CONDITIONS AT
TIMES.
OUTLOOK...
MONDAY AND TUESDAY...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS.
LOCAL IFR IN LAKE EFFECT SNOW SHOWERS EAST AND SOUTHEAST OF THE
LAKES.
WEDNESDAY AND THURSDAY...VFR/MVFR WITH A CHANCE OF SNOW
SHOWERS.
&&
.MARINE...
WINDS HAVE RELAXED ACROSS THE LAKES EARLY THIS MORNING.
HOWEVER...ANOTHER ROUND OF SMALL CRAFT ADVISORY CONDITIONS WILL
DEVELOP TONIGHT INTO MONDAY MORNING AS COLD AIR RUSHES BACK INTO THE
LOWER LAKES ON MODERATE TO STRONG NORTHWEST WINDS.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
MONDAY FOR LEZ020-040-041.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 10 AM
EST MONDAY FOR LOZ030.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 10 PM EST
MONDAY FOR LOZ043>045.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 4 PM EST
MONDAY FOR LOZ042.
&&
$$
SYNOPSIS...TJP
NEAR TERM...APFFEL/TJP
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...APFFEL/TJP
MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
311 AM EST SUN DEC 29 2013
.SYNOPSIS...
CLOUDS WILL BE ON THE INCREASE THIS MORNING WITH PRECIPITATION
GRADUALLY OVERSPREADING BY AFTERNOON AS A FAST MOVING STORM SYSTEM
MOVES UP THE EAST COAST. PRECIPITATION INITIALLY IN THE FORM OF
RAIN WILL CHANGEOVER TO SNOW BY LATE AFTERNOON AND EARLY
EVENING ACROSS MOST AREAS...WITH THE HEAVIEST ACCUMULATIONS EXPECTED
ACROSS THE WESTERN CATSKILLS. AFTER THIS STORM PASSES...MUCH
COOLER AIR WILL SETTLE ACROSS THE REGION AS ARCTIC HIGH PRESSURE
BUILDS SOUTH FROM CANADA. THE NEXT CHANCE FOR ORGANIZED SNOWFALL
WILL COME ON TUESDAY AS A STORM SYSTEM PASSES TO OUR NORTH.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
115 AM UPDATE...
AS OF 1 AM...TEMPERATURES WERE BEGINNING TO WARM WEST OF THE I-81
CORRIDOR AS WARM AIR ADVECTION INCREASES IN ADVANCE OF A STORM
SYSTEM MOVING THROUGH THE WESTERN AND CENTRAL GREAT LAKES. THAT
SAID...MAIN ATTENTION REMAINS WELL TO OUR SOUTH THIS MORNING AS
WATER VAPOR SHOWS A FAIRLY COMPACT STORM SYSTEM RAPIDLY LIFTING
THROUGH THE DEEP SOUTH. THIS FEATURE WILL CONTINUE MOVING NORTH
ALONG THE EAST COAST TODAY WITH PRECIPITATION EXPECTED TO
GRADUALLY OVERSPREAD THE REGION LATE THIS MORNING AND EARLY
AFTERNOON. STILL TRYING TO ASCERTAIN KEY IMPACTS FROM THIS SYSTEM
HOWEVER WITH THE CURRENT LINE OF THOUGHT BEING THAT PRECIP WILL
FALL MOSTLY IN THE FORM OF RAIN EARLY ON...WITH A GRADUAL
CHANGEOVER TO SNOW AS THE SYSTEM DEEPENS OVER SOUTHERN NEW ENGLAND
AND PULLS AWAY FROM THE AREA. FCST MODELS STILL DISAGREE ON THE
THERMAL STRUCTURE OF THE ATMOSPHERE WITH THE NAM NOW THE COOLEST
OF ALL SOLUTIONS. IF THIS MODEL WERE TO VERIFY...PRECIP WOULD
MAINLY BE IN THE FORM OF SNOW...WHILE THE GFS AND RUC SUGGEST MUCH
OF THE PRECIP WILL BE IN THE FORM OF RAIN. IN ANY EVENT...MANY
DECISIONS STILL NEED TO BE MADE BEFORE THE 430 AM UPDATE.
PREVIOUS NEAR TERM DISCUSSION...
CLOUDS OVER THE NORTHERN PORTION OF THE
FORECAST AREA SWEPT OUT TO THE NORTHEAST. A LITTLE FOG DEVELOPED
IN THE ROME AREA BUT SHOULD ONLY LAST A FEW HOURS AT BEST. HIGH
CIRRUS AHEAD OF THE NEXT WEATHER SYSTEM HAVE RAPIDLY MOVED IN FROM
THE SOUTHWEST ACROSS NE PA AND CENTRAL NY. HAVE MADE MINOR
ADJUSTMENT TO THE FORECAST FOR OVERNIGHT. TEMPERATURES ARE RUNNING
WARMER ON THE HILLS WITH COLDER IN THE VALLEYS. VALLEYS SAW A
QUICK DROP IN TEMPS UNDER CLEAR SKIES ONCE THE SUN WAS LOW TO THE
HORIZON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
INTRSTG WX EVENT APRCHG IN THE SHRT TERM AS A DVLPG LOW MVES UP
THE EAST CST. PLENTY OF COLD AIR AVBL BUT SYSTEM IS BLOCKED FROM
GRABBING THE COLD AIR...AT LEAST AT THE BEGINNING...MAINLY DUE TO
A LACK OF PHASING WITH A NRN STREAM SYSTEM RIDING ALONG THE ARCTIC
FNT OVER SRN CANADA. EVENTUALLY...SOME EVAPORATIONAL COOLING AND A
BIT OF COLDER AIR ALLOWS THE PCPN TO FALL AS SNOW VERY LATE IN THE
DAY SUN...AND AS THE STORM PULLS OUT SUN NGT. AS THE PCPN MVES
IN...A LL WARM LYR KEEPS THE PCPN AS RAIN UNTIL A TRICKY AND DEEP
ISOTHERMAL LYR NEAR FRZG DVLPS LATE IN THE DAY. THIS WILL
EVENTUALLY ALLOW A CHG OVER TO SNOW...PRBLY OVER THE HIER
ELEVATIONS IN NY FIRST...ESP THE WRN CATS AND PARTS OF THE FINGER
LAKES. HWVR...AS THE SFC REMAINS RGT NEAR FRZG...ACCUMULATION OF
SNOW WILL BE SLOW AT FIRST. THEN...OVRNGT...A QUICK CPL INCHES
PSBL. HWVR...A QUICKER CHG OVER COULD BOOST ACCUMS TO NEARER 4
INCHES.
CAA CONTS ON MON WITH H8 TEMPS DROPPING TO -14C BY LATE IN THE
DAY. HWVR...SIGNIFICANT SHEAR SHD LIMT LE TO SCT SNOW
SHWRS...MAINLY OVER THE FINGER LAKES AND WRN SUSQ REGION.
SFC HIPRES BLDS IN FOR TUE KEEPING CONDS GNRLY DRY OTR THAN SOME
LGT LE.
MODEL GUID CONTD TO BE IN DECENT AGREEMENT THRU THE PD RESULTING
IN HIER CONFIDENCE IN TEMPS AND POP FCSTS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
310 AM UPDATE...MEDIUM RANGE MODELS CONTINUE TO SHOW A POSITIVE
PNA PATTERN THROUGH THE PERIOD WITH A WESTERN RIDGE AND EASTERN
TROF. MODELS CONTINUE TO SHOW A FAIRLY STRONG QUICK MOVING SYSTEM
THAT TRACKS FROM THE MID WEST ACROSS THE OHIO VALLEY THEN OFF THE
MID ATLANTIC COAST WED NIGHT THROUGH THURSDAY EVENING. INCREASED
POPS INTO THE HIGH CHC CATEGORY DURING THIS PERIOD WITH SEVERAL
INCHES OF SNOW POSSIBLE FOR THE FORECAST AREA. ONCE THIS SYSTEM
DEPARTS A VERY COLD AIRMASS WILL SETTLE OVER THE REGION AS SFC
HIGH PRES IN EASTERN CANADA PROVIDES A N/NE FLOW. T85 DROPS INTO
THE -20C/-25C RANGE FRIDAY/FRIDAY NIGHT RESULTING IN MAXES OF 5 TO
15 DEGREES AND LOWS AROUND ZERO.
PREVIOUS DISC...
PNA PTRN PREVAILS...AND FOLLOWED WPC GUIDANCE. HOWEVER...CHGS
WERE MADE TO THE TUE NGT/WED TIME FRAME WITH MORE CLDS AND HIGHER
POPS AS MDLS SHOW DVLPMNT OF LGT OVERRUNNING PCPN ASSCD WITH A
S/WV SCOOTING FROM THE OH VLY INTO THE NRN MID ATLC. AFTER THIS
TIME...DIFFS ARISE WITH LATE WEEK SYSTEM...WITH GFS SUGGESTING
MORE OF IMPACT ON THE FCST AREA. 00Z EURO KEEPS THE BULK OF THIS
ACTION WELL SOUTH OF THE RGN. COLD TEMPS WITH HIGHS IN THE TEENS AND
LOWS DROPPING INTO THE SINGLE DIGITS (COLDER IN NRN SXNS) BEFORE
MODERATING LATE IN THE PD.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
LOW PRES WILL TRACK THROUGH THE MID ATLANTIC REGION THIS MORNING
THEN ALONG THE EAST COAST LATE THIS AFTERNOON THROUGH THE EVENING
HOURS. EXCEPT FOR MVFR/IFR FOG AT KRME THROUGH DAYBREAK, VFR
CONDITIONS WILL CONTINUE AS MID/HIGH CLOUDS THICKEN. LIGHT RAIN
WITH MVFR CONDITIONS WILL SPREAD FROM SOUTH TO NORTH ACROSS THE
TERMINALS DURING THE LATE MORNING AND EARLY AFTERNOON PERIOD.
AT KITH/KBGM/KELM, MIXED RAIN/SNOW WILL OCCUR BEGINNING AROUND
21Z. CONFIDENCE HERE IS LOW FOR P-TYPE DUE TO MODEL DIFFERENCES
AND BOUNDARY LAYER TEMPS VERY CLOSE TO FREEZING. AT KRME/KSYR, BY
03Z CAA WILL ALLOW ANY REMAINING PRECIP TO CHANGE TO MVFR SNOW
SHOWERS. AT KITH/KBGM/KELM, AFTER 03Z PRECIP WILL END BUT MVFR
CIGS WILL PERSIST. AT KAVP, IFR CONDITIONS IN LIGHT TO MODERATE
RAIN WILL PREVAIL THROUGH THE MID/LATE AFTERNOON THEN END AROUND
00Z BUT MVFR CIGS WILL CONTINUE.
LIGHT WINDS EARLY THIS MORNING BECOMING S/SE AROUND 5 KNOTS
GRADUALLY SHIFTING TO THE SOUTHWEST THEN WEST LATE IN THE TAF
PERIOD.
OUTLOOK...
MON...SCT MVFR IN -SHSN ACRS CNTRL NY.
MON NGT...MAINLY VFR.
TUE...SCT MVFR IN -SHSN ACRS CNTRL NY.
TUE NGT/WED...IFR/MVFR IN -SHSN.
THU...IFR SNOW DEVELOPING.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...BMW/CMG
SHORT TERM...DGM
LONG TERM...RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
120 AM EST SUN DEC 29 2013
.SYNOPSIS...
CLOUDS WILL BE ON THE INCREASE THIS MORNING WITH PRECIPITATION
GRADUALLY OVERSPREADING BY AFTERNOON AS A FAST MOVING STORM SYSTEM
MOVES UP THE EAST COAST. PRECIPITATION INITIALLY IN THE FORM OF
RAIN WILL CHANGEOVER TO SNOW BY LATE AFTERNOON AND EARLY
EVENING ACROSS MOST AREAS...WITH THE HEAVIEST ACCUMULATIONS EXPECTED
ACROSS THE WESTERN CATSKILLS. AFTER THIS STORM PASSES...MUCH
COOLER AIR WILL SETTLE ACROSS THE REGION AS ARCTIC HIGH PRESSURE
BUILDS SOUTH FROM CANADA. THE NEXT CHANCE FOR ORGANIZED SNOWFALL
WILL COME ON TUESDAY AS A STORM SYSTEM PASSES TO OUR NORTH.
&&
.NEAR TERM /THROUGH TODAY/...
115 AM UPDATE...
AS OF 1 AM...TEMPERATURES WERE BEGINNING TO WARM WEST OF THE I-81
CORRIDOR AS WARM AIR ADVECTION INCREASES IN ADVANCE OF A STORM
SYSTEM MOVING THROUGH THE WESTERN AND CENTRAL GREAT LAKES. THAT
SAID...MAIN ATTENTION REMAINS WELL TO OUR SOUTH THIS MORNING AS
WATER VAPOR SHOWS A FAIRLY COMPACT STORM SYSTEM RAPIDLY LIFTING
THROUGH THE DEEP SOUTH. THIS FEATURE WILL CONTINUE MOVING NORTH
ALONG THE EAST COAST TODAY WITH PRECIPITATION EXPECTED TO
GRADUALLY OVERSPREAD THE REGION LATE THIS MORNING AND EARLY
AFTERNOON. STILL TRYING TO ASCERTAIN KEY IMPACTS FROM THIS SYSTEM
HOWEVER WITH THE CURRENT LINE OF THOUGHT BEING THAT PRECIP WILL
FALL MOSTLY IN THE FORM OF RAIN EARLY ON...WITH A GRADUAL
CHANGEOVER TO SNOW AS THE SYSTEM DEEPENS OVER SOUTHERN NEW ENGLAND
AND PULLS AWAY FROM THE AREA. FCST MODELS STILL DISAGREE ON THE
THERMAL STRUCTURE OF THE ATMOSPHERE WITH THE NAM NOW THE COOLEST
OF ALL SOLUTIONS. IF THIS MODEL WERE TO VERIFY...PRECIP WOULD
MAINLY BE IN THE FORM OF SNOW...WHILE THE GFS AND RUC SUGGEST MUCH
OF THE PRECIP WILL BE IN THE FORM OF RAIN. IN ANY EVENT...MANY
DECISIONS STILL NEED TO BE MADE BEFORE THE 430 AM UPDATE.
PREVIOUS NEAR TERM DISCUSSION...
CLOUDS OVER THE NORTHERN PORTION OF THE
FORECAST AREA SWEPT OUT TO THE NORTHEAST. A LITTLE FOG DEVELOPED
IN THE ROME AREA BUT SHOULD ONLY LAST A FEW HOURS AT BEST. HIGH
CIRRUS AHEAD OF THE NEXT WEATHER SYSTEM HAVE RAPIDLY MOVED IN FROM
THE SOUTHWEST ACROSS NE PA AND CENTRAL NY. HAVE MADE MINOR
ADJUSTMENT TO THE FORECAST FOR OVERNIGHT. TEMPERATURES ARE RUNNING
WARMER ON THE HILLS WITH COLDER IN THE VALLEYS. VALLEYS SAW A
QUICK DROP IN TEMPS UNDER CLEAR SKIES ONCE THE SUN WAS LOW TO THE
HORIZON.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
INTRSTG WX EVENT APRCHG IN THE SHRT TERM AS A DVLPG LOW MVES UP
THE EAST CST. PLENTY OF COLD AIR AVBL BUT SYSTEM IS BLOCKED FROM
GRABBING THE COLD AIR...AT LEAST AT THE BEGINNING...MAINLY DUE TO
A LACK OF PHASING WITH A NRN STREAM SYSTEM RIDING ALONG THE ARCTIC
FNT OVER SRN CANADA. EVENTUALLY...SOME EVAPORATIONAL COOLING AND A
BIT OF COLDER AIR ALLOWS THE PCPN TO FALL AS SNOW VERY LATE IN THE
DAY SUN...AND AS THE STORM PULLS OUT SUN NGT. AS THE PCPN MVES
IN...A LL WARM LYR KEEPS THE PCPN AS RAIN UNTIL A TRICKY AND DEEP
ISOTHERMAL LYR NEAR FRZG DVLPS LATE IN THE DAY. THIS WILL
EVENTUALLY ALLOW A CHG OVER TO SNOW...PRBLY OVER THE HIER
ELEVATIONS IN NY FIRST...ESP THE WRN CATS AND PARTS OF THE FINGER
LAKES. HWVR...AS THE SFC REMAINS RGT NEAR FRZG...ACCUMULATION OF
SNOW WILL BE SLOW AT FIRST. THEN...OVRNGT...A QUICK CPL INCHES
PSBL. HWVR...A QUICKER CHG OVER COULD BOOST ACCUMS TO NEARER 4
INCHES.
CAA CONTS ON MON WITH H8 TEMPS DROPPING TO -14C BY LATE IN THE
DAY. HWVR...SIGNIFICANT SHEAR SHD LIMT LE TO SCT SNOW
SHWRS...MAINLY OVER THE FINGER LAKES AND WRN SUSQ REGION.
SFC HIPRES BLDS IN FOR TUE KEEPING CONDS GNRLY DRY OTR THAN SOME
LGT LE.
MODEL GUID CONTD TO BE IN DECENT AGREEMENT THRU THE PD RESULTING
IN HIER CONFIDENCE IN TEMPS AND POP FCSTS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
PNA PTRN PREVAILS...AND FOLLOWED WPC GUIDANCE. HOWEVER...CHGS
WERE MADE TO THE TUE NGT/WED TIME FRAME WITH MORE CLDS AND HIGHER
POPS AS MDLS SHOW DVLPMNT OF LGT OVERRUNNING PCPN ASSCD WITH A
S/WV SCOOTING FROM THE OH VLY INTO THE NRN MID ATLC. AFTER THIS
TIME...DIFFS ARISE WITH LATE WEEK SYSTEM...WITH GFS SUGGESTING
MORE OF IMPACT ON THE FCST AREA. 00Z EURO KEEPS THE BULK OF THIS
ACTION WELL SOUTH OF THE RGN. COLD TEMPS WITH HIGHS IN THE TEENS AND
LOWS DROPPING INTO THE SINGLE DIGITS (COLDER IN NRN SXNS) BEFORE
MODERATING LATE IN THE PD.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
LOW PRES WILL TRACK THROUGH THE MID ATLANTIC REGION THIS MORNING
THEN ALONG THE EAST COAST LATE THIS AFTERNOON THROUGH THE EVENING
HOURS. EXCEPT FOR MVFR/IFR FOG AT KRME THROUGH DAYBREAK, VFR
CONDITIONS WILL CONTINUE AS MID/HIGH CLOUDS THICKEN. LIGHT RAIN
WITH MVFR CONDITIONS WILL SPREAD FROM SOUTH TO NORTH ACROSS THE
TERMINALS DURING THE LATE MORNING AND EARLY AFTERNOON PERIOD.
AT KITH/KBGM/KELM, MIXED RAIN/SNOW WILL OCCUR BEGINNING AROUND
21Z. CONFIDENCE HERE IS LOW FOR P-TYPE DUE TO MODEL DIFFERENCES
AND BOUNDARY LAYER TEMPS VERY CLOSE TO FREEZING. AT KRME/KSYR, BY
03Z CAA WILL ALLOW ANY REMAINING PRECIP TO CHANGE TO MVFR SNOW
SHOWERS. AT KITH/KBGM/KELM, AFTER 03Z PRECIP WILL END BUT MVFR
CIGS WILL PERSIST. AT KAVP, IFR CONDITIONS IN LIGHT TO MODERATE
RAIN WILL PREVAIL THROUGH THE MID/LATE AFTERNOON THEN END AROUND
00Z BUT MVFR CIGS WILL CONTINUE.
LIGHT WINDS EARLY THIS MORNING BECOMING S/SE AROUND 5 KNOTS
GRADUALLY SHIFTING TO THE SOUTHWEST THEN WEST LATE IN THE TAF
PERIOD.
OUTLOOK...
MON...SCT MVFR IN -SHSN ACRS CNTRL NY.
MON NGT...MAINLY VFR.
TUE...SCT MVFR IN -SHSN ACRS CNTRL NY.
TUE NGT/WED...IFR/MVFR IN -SHSN.
THU...IFR SNOW DEVELOPING.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...BMW/CMG
SHORT TERM...DGM
LONG TERM...
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
710 AM EST SUN DEC 29 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL TRACK ACROSS THE AREA
TODAY...FOLLOWED BY THE ATTENDANT COLD FRONT SUNDAY NIGHT. ANOTHER
UPPER LEVEL DISTURBANCE WILL CROSS THE REGION MONDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 250 AM SUNDAY...
AN UPPER LOW OVER THE LOWER MISSISSIPPI RIVER VALLEY WILL CONTINUE
TO LIFT NORTHEAST TODAY...DEAMPLIFYING AS IT BECOMES INCREASINGLY
NEGATIVELY TILTED. THE ASSOCIATED DCVA AND 50-60 LOW LEVEL JET WILL
DEEPEN AND ACCELERATE A SURFACE LOW...CURRENTLY DEVELOPING OVER THE
FLORIDA PANHANDLE...TOWARD THE DELMARVA AREA TODAY.
NOT A LOT OF CHANGES TO MAKE TO THE CURRENT FORECAST. AREAS OF
LIGHT RAIN OVER SPREADING THE AREA ARE CREATING AN IN-SITU COLD AIR
DAMMING AIRMASS AND STRENGTHENING THE STABILITY ACROSS THE CWA.
MODELS HAVE TRENDED A LITTLE EAST WITH THE TRACK OF THE SURFACE
LOW...ESPECIALLY THE GFS...THOUGH NOT AS MUCH AS ONE MIGHT EXPECT IF
THEY ARE CATCHING ONTO THE CAD AIRMASS. A CONSENSUS WOULD TRACK THE
LOW UP THE I-95 CORRIDOR BETWEEN 15Z AND 18Z. THE COASTAL WARM
FRONT AND 55-65F DEWPOINT AIR ALONG THE CAROLINA COAST WILL SURGE
INLAND AS PRESSURES BEGIN TO FALL...BUT IT APPEARS THE BETTER
MARITIME AIRMASS THAT WOULD LEAD TO BETTER DESTABILIZATION AND
SEVERE THREAT WILL STAY ALONG THE COAST...HINDERED BY THE STABLE CAD
AIRMASS. STILL..THERE MAY BE A BRIEF PERIOD (15-18Z) WHERE 250-500
J/KG OF NEAR SURFACE BASED CAPE CAN PHASE WITH HODOGRAPHS FAVORABLE
OF LOW-TOPPED ROTATING STORMS OVER THE COASTAL PLAIN. ON THE HEELS
OF THE SURFACE LOW...A BROKEN LINE OF SHOWERS SHOULD DEVELOP ALONG
THE WEAK COLD FRONT AND CONVERGENCE ZONE...WHICH COULD STILL PRODUCE
SOME STRONG WIND GUSTS VIA DOWNWARD MOMENTUM TRANSPORT ON THE TAIL
END OF THE LOW LEVEL JET.
CATEGORICAL POPS DURING THE FIRST HALF OF THE DAY WILL TREND DOWN
QUICKLY FROM SOUTHWEST TO NORTHEAST AFTER 18Z AND THE CWA WILL BE
COMPLETELY DRY BY 00Z. HARD TO GET A SOLID HANDLE ON QPF AMOUNTS AS
PRECIP IS JUST NOW BEGINNING TO FILL IN ACROSS THE CWA. THE FOCI
FOR HEAVIER PRECIP WILL BE THE LLJ ENHANCED ISENTROPIC ACCENT OVER
THE CAD COLD DOME IN THE WEST AND ALSO THE SURFACE LOW/FRONTAL
PRECIP BAND OVER THE COASTAL PLAIN. HOURLY RAINFALL RATES UPSTREAM
ARE AROUND 0.10" TO 0.25"...WHICH AGREE WELL WITH THE RAP AND HRRR.
BASED ON THIS...A WIDESPREAD 1-1.5" STILL SEEMS REASONABLE.
REGARDING TEMPS...THE CWA WILL BE SPLIT BY THE INLAND PUSH OF THE
WARM SECTOR...WITH MID AND UPPER 40S OVER THE WESTERN PIEDMONT AND
UPPER 50S TO POSSIBLE MID 60S OVER THE COASTAL PLAIN. THERE IS A
CHANCE THAT WESTERLY WIND AND PARTIAL CLEARING BEHIND THE FRONT MAY
ALLOW TEMPS IN THE TRIAD TO JUMP A COUPLE EXTRA DEGREES BEFORE
SUNSET.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 300 AM SUNDAY...
IN THE WAKE OF THE DEPARTING LOW PRESSURE SYSTEM...LOW LEVEL
MOISTURE WILL SLOWLY SCOUR VIA A WESTERLY WIND SUNDAY EVENING/NIGHT.
CIRRUS SHOULD SPREAD BACK IN FROM THE SOUTHWEST OVERNIGHT AND DURING
THE DAY MONDAY AHEAD OF A WAVE MOVING THROUGH THE MEAN UPPER TROUGH.
A WEAKENING MSLP GRADIENT AND AT LEAST PARTIAL CLEARING MAY LEAD TO
FOG POTENTIAL...THOUGH CONFIDENCE IN THIS IS LOW AT THE MOMENT.
LOWS 36-41. HIGHS MONDAY 49-56. -SMITH
MONDAY NIGHT:
THE PASSAGE OF THE MID/UPPER LEVEL TROUGH AND EMBEDDED
VIGOROUS SHORTWAVE WILL BRING AN INCREASE IN CLOUDS WITH SOME LIGHT
PRECIP DEVELOPING OVER THE AREA BETWEEN 06 TO 12Z TUESDAY IN
RESPONSE TO LOW AND MID-LEVEL FGEN UNDERNEATH RENEWED UPPER-LEVEL
DIVERGENCE WITHIN THE RIGHT ENTRANCE REGION OF A 150 JET CENTERED
OVER THE MID-ATLANTIC SEABOARD. THE GFS AND NAM EVEN SPIN UP A WEAK
SFC WAVE ALONG THE LINGERING FRONTAL BOUNDARY OFF THE NC COAST. THE
ECWMF WHICH HAD BEEN A DRY OUTLIER...HAS NOW JUMPED ON BOARD...WITH
AVERAGE QPF AMOUNTS OF 0.03 TO 0.06" ACROSS THE AREA.
FCST SOUNDINGS ARE MUCH WARMER IN THE BOUNDARY LAYER AND SATURATION
IS MUCH SHALLOWER...WITH NO SEEDING OF ICE FROM ABOVE GIVEN CLOUD
SEPARATION OF AROUND 10KFT. THUS HAVE REMOVED ANY MENTION OF SNOW
WITH JUST RAIN. LOWS IN THE MID 30S NW TO UPPER 30S/NEAR 40 SE.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
TUESDAY AND WEDNESDAY:
UNDERNEATH ZONAL FLOW ALOFT...EXPECT DRY CONDITIONS WITH
TEMPERATURES AT OR JUST BELOW NORMAL AS THE MODIFIED CANADIAN HIGH
BUILDS EASTWARD OVER THE AREA.
THURSDAY THROUGH SATURDAY:
THERE REMAINS CONSIDERABLE UNCERTAINTY AND LARGE MODEL SPREAD AMONG
THE DETERMINISTIC MODEL GUIDANCE AND ENSEMBLES WITH RESPECT TO THE
UPSTREAM AMPLIFICATION/TIMING OF A NORTHERN STREAM WAVE DROPPING
SEWD THROUGH THE BASE OF THE MEAN TROUGH AND RESULTANT DOWNSTREAM
MILLER-B TYPE CYCLOGENESIS ALONG THE MID-ATLANTIC COAST. THE ECWMF
CONTINUES TO BE ON THE DEEPER/SLOWER SIDE OF GUIDANCE...BUT EVEN IT
HAS BACKED WITH PRECIP ACROSS THE AREA FOR WITH VERY LITTLE TO NO
SOUTHERN STREAM MOISTURE LINKAGE. MEANWHILE...THE QUICKER/MORE
PROGRESSIVE GFS REMAINS DRY. WILL HAVE TO CONTINUE MONITOR THIS
SYSTEM...PARTICULARLY THE TIMING AND JUST HOW CLOSE TO THE COAST THE
SYSTEM WILL DEVELOP. WILL KEEPS POPS IN THE SLGT CHC FOR THURSDAY
WITH FRIDAY DRY AS EVEN THE SLOWER EC HAS US DRY SLOTTED BY THEN.
OTHERWISE...TEMPS WILL GENERALLY BE NEAR OR SLIGHTLY BELOW NORMAL
THURSDAY DEPENDING ON PRECIP CHANCES...THEN WELL BELOW NORMAL BEHIND
THE SYSTEM ON FRIDAY AND INTO THE FIRST PART OF THE WEEKEND AS
ANOTHER ARCTIC HIGH BUILDS EASTWARD INTO THE REGION
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 710 AM SUNDAY...
A LOW PRESSURE SYSTEM WILL LIFT NORTHEAST ACROSS THE REGION
TODAY...WITH ADVERSE AVIATION CONDITIONS TO CONTINUE THROUGH THIS
AFTERNOON. WIDESPREAD MODERATE RAIN MOVING ACROSS CENTRAL NC WILL
MAINTAIN THE IFR AND LIFR CEILINGS THIS MORNING. MEANWHILE...AN
INTENSE SOUTHERLY LOW LEVEL JET IS CURRENTLY SURGING ACROSS THE AREA
AND CREATING A THREAT OF LOW LEVEL WIND SHEAR. LATER THIS MORNING
(BETWEEN ROUGHLY 15Z AND 18Z)...THE AFOREMENTIONED LOW WILL MOVE
ACROSS EASTERN NC...AT WHICH TIME WINDS WILL BEGIN TO VEER AROUND TO
SOUTHWESTERLY. CEILINGS SHOULD BEGIN TO SCATTER AND LIFT OVER THE
COASTAL PLAIN...POSSIBLY REACHING MVFR BY AROUND 16-17Z. WINDS WILL
INCREASE TO AROUND 15MPH AND MAY GUSTS TO 25-30MPH IN HEAVIER
SHOWERS. THERE IS STILL A SMALL CHANCE OF AN ISOLATED THUNDERSTORMS
FROM KFAY TO KRWI. ONCE THE LOW MOVES OFF TO THE NORTHEAST...A COLD
FRONT WILL SWEEP ACROSS THE AREA AND SCOUR THE REMAIN LOW LEVEL
MOISTURE....WITH VFR CONDITIONS TO RETURN BY 21-00Z WITH A LIGHT
WESTERLY WIND. IF SKIES REMAIN CLEAR TONIGHT AND WINDS ARE WEAK
ENOUGH... THERE MAY ENOUGH LOW LEVEL MOISTURE FOR PATCHY
FOG...MAINLY ACROSS THE SANDHILLS AND SOUTHERN COASTAL PLAIN.
LOOKING AHEAD: ANOTHER UPPER LEVEL DISTURBANCE WILL CROSS THE AREA
MONDAY NIGHT...WHICH MAY CREATE ISOLATED SHOWERS AND A BRIEF PERIOD
OF SUB-VFR CONDITIONS. VFR CONDITIONS ARE THEN EXPECTED THROUGH
WEDNESDAY...WITH ANOTHER CHANCE OF RAIN BY THURSDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...SMITH/CBL
LONG TERM...CBL
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
306 AM EST SUN DEC 29 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL TRACK ACROSS THE AREA
TODAY...FOLLOWED BY THE ATTENDANT COLD FRONT SUNDAY NIGHT. ANOTHER
UPPER LEVEL DISTURBANCE WILL CROSS THE REGION MONDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 250 AM SUNDAY...
AN UPPER LOW OVER THE LOWER MISSISSIPPI RIVER VALLEY WILL CONTINUE
TO LIFT NORTHEAST TODAY...DEAMPLIFYING AS IT BECOMES INCREASINGLY
NEGATIVELY TILTED. THE ASSOCIATED DCVA AND 50-60 LOW LEVEL JET WILL
DEEPEN AND ACCELERATE A SURFACE LOW...CURRENTLY DEVELOPING OVER THE
FLORIDA PANHANDLE...TOWARD THE DELMARVA AREA TODAY.
NOT A LOT OF CHANGES TO MAKE TO THE CURRENT FORECAST. AREAS OF
LIGHT RAIN OVER SPREADING THE AREA ARE CREATING AN IN-SITU COLD AIR
DAMMING AIRMASS AND STRENGTHENING THE STABILITY ACROSS THE CWA.
MODELS HAVE TRENDED A LITTLE EAST WITH THE TRACK OF THE SURFACE
LOW...ESPECIALLY THE GFS...THOUGH NOT AS MUCH AS ONE MIGHT EXPECT IF
THEY ARE CATCHING ONTO THE CAD AIRMASS. A CONSENSUS WOULD TRACK THE
LOW UP THE I-95 CORRIDOR BETWEEN 15Z AND 18Z. THE COASTAL WARM
FRONT AND 55-65F DEWPOINT AIR ALONG THE CAROLINA COAST WILL SURGE
INLAND AS PRESSURES BEGIN TO FALL...BUT IT APPEARS THE BETTER
MARITIME AIRMASS THAT WOULD LEAD TO BETTER DESTABILIZATION AND
SEVERE THREAT WILL STAY ALONG THE COAST...HINDERED BY THE STABLE CAD
AIRMASS. STILL..THERE MAY BE A BRIEF PERIOD (15-18Z) WHERE 250-500
J/KG OF NEAR SURFACE BASED CAPE CAN PHASE WITH HODOGRAPHS FAVORABLE
OF LOW-TOPPED ROTATING STORMS OVER THE COASTAL PLAIN. ON THE HEELS
OF THE SURFACE LOW...A BROKEN LINE OF SHOWERS SHOULD DEVELOP ALONG
THE WEAK COLD FRONT AND CONVERGENCE ZONE...WHICH COULD STILL PRODUCE
SOME STRONG WIND GUSTS VIA DOWNWARD MOMENTUM TRANSPORT ON THE TAIL
END OF THE LOW LEVEL JET.
CATEGORICAL POPS DURING THE FIRST HALF OF THE DAY WILL TREND DOWN
QUICKLY FROM SOUTHWEST TO NORTHEAST AFTER 18Z AND THE CWA WILL BE
COMPLETELY DRY BY 00Z. HARD TO GET A SOLID HANDLE ON QPF AMOUNTS AS
PRECIP IS JUST NOW BEGINNING TO FILL IN ACROSS THE CWA. THE FOCI
FOR HEAVIER PRECIP WILL BE THE LLJ ENHANCED ISENTROPIC ACCENT OVER
THE CAD COLD DOME IN THE WEST AND ALSO THE SURFACE LOW/FRONTAL
PRECIP BAND OVER THE COASTAL PLAIN. HOURLY RAINFALL RATES UPSTREAM
ARE AROUND 0.10" TO 0.25"...WHICH AGREE WELL WITH THE RAP AND HRRR.
BASED ON THIS...A WIDESPREAD 1-1.5" STILL SEEMS REASONABLE.
REGARDING TEMPS...THE CWA WILL BE SPLIT BY THE INLAND PUSH OF THE
WARM SECTOR...WITH MID AND UPPER 40S OVER THE WESTERN PIEDMONT AND
UPPER 50S TO POSSIBLE MID 60S OVER THE COASTAL PLAIN. THERE IS A
CHANCE THAT WESTERLY WIND AND PARTIAL CLEARING BEHIND THE FRONT MAY
ALLOW TEMPS IN THE TRIAD TO JUMP A COUPLE EXTRA DEGREES BEFORE
SUNSET.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 300 AM SUNDAY...
IN THE WAKE OF THE DEPARTING LOW PRESSURE SYSTEM...LOW LEVEL
MOISTURE WILL SLOWLY SCOUR VIA A WESTERLY WIND SUNDAY EVENING/NIGHT.
CIRRUS SHOULD SPREAD BACK IN FROM THE SOUTHWEST OVERNIGHT AND DURING
THE DAY MONDAY AHEAD OF A WAVE MOVING THROUGH THE MEAN UPPER TROUGH.
A WEAKENING MSLP GRADIENT AND AT LEAST PARTIAL CLEARING MAY LEAD TO
FOG POTENTIAL...THOUGH CONFIDENCE IN THIS IS LOW AT THE MOMENT.
LOWS 36-41. HIGHS MONDAY 49-56. -SMITH
MONDAY NIGHT:
THE PASSAGE OF THE MID/UPPER LEVEL TROUGH AND EMBEDDED
VIGOROUS SHORTWAVE WILL BRING AN INCREASE IN CLOUDS WITH SOME LIGHT
PRECIP DEVELOPING OVER THE AREA BETWEEN 06 TO 12Z TUESDAY IN
RESPONSE TO LOW AND MID-LEVEL FGEN UNDERNEATH RENEWED UPPER-LEVEL
DIVERGENCE WITHIN THE RIGHT ENTRANCE REGION OF A 150 JET CENTERED
OVER THE MID-ATLANTIC SEABOARD. THE GFS AND NAM EVEN SPIN UP A WEAK
SFC WAVE ALONG THE LINGERING FRONTAL BOUNDARY OFF THE NC COAST. THE
ECWMF WHICH HAD BEEN A DRY OUTLIER...HAS NOW JUMPED ON BOARD...WITH
AVERAGE QPF AMOUNTS OF 0.03 TO 0.06" ACROSS THE AREA.
FCST SOUNDINGS ARE MUCH WARMER IN THE BOUNDARY LAYER AND SATURATION
IS MUCH SHALLOWER...WITH NO SEEDING OF ICE FROM ABOVE GIVEN CLOUD
SEPARATION OF AROUND 10KFT. THUS HAVE REMOVED ANY MENTION OF SNOW
WITH JUST RAIN. LOWS IN THE MID 30S NW TO UPPER 30S/NEAR 40 SE.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
TUESDAY AND WEDNESDAY:
UNDERNEATH ZONAL FLOW ALOFT...EXPECT DRY CONDITIONS WITH
TEMPERATURES AT OR JUST BELOW NORMAL AS THE MODIFIED CANADIAN HIGH
BUILDS EASTWARD OVER THE AREA.
THURSDAY THROUGH SATURDAY:
THERE REMAINS CONSIDERABLE UNCERTAINTY AND LARGE MODEL SPREAD AMONG
THE DETERMINISTIC MODEL GUIDANCE AND ENSEMBLES WITH RESPECT TO THE
UPSTREAM AMPLIFICATION/TIMING OF A NORTHERN STREAM WAVE DROPPING
SEWD THROUGH THE BASE OF THE MEAN TROUGH AND RESULTANT DOWNSTREAM
MILLER-B TYPE CYCLOGENESIS ALONG THE MID-ATLANTIC COAST. THE ECWMF
CONTINUES TO BE ON THE DEEPER/SLOWER SIDE OF GUIDANCE...BUT EVEN IT
HAS BACKED WITH PRECIP ACROSS THE AREA FOR WITH VERY LITTLE TO NO
SOUTHERN STREAM MOISTURE LINKAGE. MEANWHILE...THE QUICKER/MORE
PROGRESSIVE GFS REMAINS DRY. WILL HAVE TO CONTINUE MONITOR THIS
SYSTEM...PARTICULARLY THE TIMING AND JUST HOW CLOSE TO THE COAST THE
SYSTEM WILL DEVELOP. WILL KEEPS POPS IN THE SLGT CHC FOR THURSDAY
WITH FRIDAY DRY AS EVEN THE SLOWER EC HAS US DRY SLOTTED BY THEN.
OTHERWISE...TEMPS WILL GENERALLY BE NEAR OR SLIGHTLY BELOW NORMAL
THURSDAY DEPENDING ON PRECIP CHANCES...THEN WELL BELOW NORMAL BEHIND
THE SYSTEM ON FRIDAY AND INTO THE FIRST PART OF THE WEEKEND AS
ANOTHER ARCTIC HIGH BUILDS EASTWARD INTO THE REGION
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 1240 AM SUNDAY...
24 HOUR TAF PERIOD: AREAS OF LIGHT RAIN ARE SPREADING ACROSS CENTRAL
NC THIS MORNING AS A STORM SYSTEM BEGINS TO LIFT NORTHEAST FROM THE
GULF OF MEXICO. CEILINGS ARE MOSTLY MVFR AND VFR AT THE MOMENT BUT
WILL DROP RAPIDLY TO IFR AND LIFR BY 12Z AS MORE WIDESPREAD AND
HEAVIER RAIN OVERSPREADS THE AREA. AT THE SAME TIME...A
STRONG...SOUTHERLY LOW LEVEL JET OF AROUND 50KT WILL SURGE NORTH
ACROSS THE AREA...WHICH WILL LEAD TO A PERIOD OF LOW-LEVEL WIND
SHEAR THREAT DUE TO LIGHTER NORTHEASTERLY WINDS AT THE SURFACE. LOW-
LEVEL WIND SHEAR WILL BE MOST LIKELY BETWEEN 09Z AND
15Z...AFTERWHICH WINDS WILL START TO BECOME MORE UNIFORM OUT OF THE
SOUTHWEST AS THE STORM SYSTEM PULLS AWAY FROM THE AREA. GUSTY WINDS
WILL STILL BE POSSIBLE...ESPECIALLY IN THE EAST OF KRDU WHERE AN
ISOLATED THUNDER STORMS OR TWO IS POSSIBLE. PRECIP WILL COME TO AN
END FROM WEST TO EAST DUE THE AFTERNOON...WITH CEILINGS ALSO
SCATTERING AS WINDS BECOME MORE SOUTHWESTERLY.
LOOKING AHEAD: ANOTHER UPPER LEVEL DISTURBANCE WILL CROSS THE AREA
MONDAY NIGHT AND EARLY TUESDAY...POTENTIALLY GENERATING A FEW
SHOWERS AND A SHORT PERIOD OF SUB-VFR CEILINGS. FROM TUESDAY
AFTERNOON THROUGH EARLY THURSDAY EXPECT VFR CONDITIONS...WITH
ANOTHER POTENTIAL SHOT OF SOME RAIN THURSDAY AFT/EVE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...SMITH/CBL
LONG TERM...CBL
AVIATION...KC/SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
250 AM EST SUN DEC 29 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL TRACK ACROSS THE AREA
TODAY...FOLLOWED BY THE ATTENDANT COLD FRONT SUNDAY NIGHT. ANOTHER
UPPER LEVEL DISTURBANCE WILL CROSS THE REGION MONDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 250 AM SUNDAY...
AN UPPER LOW OVER THE LOWER MISSISSIPPI RIVER VALLEY WILL CONTINUE
TO LIFT NORTHEAST TODAY...DEAMPLIFYING AS IT BECOMES INCREASINGLY
NEGATIVELY TILTED. THE ASSOCIATED DCVA AND 50-60 LOW LEVEL JET WILL
DEEPEN AND ACCELERATE A SURFACE LOW...CURRENTLY DEVELOPING OVER THE
FLORIDA PANHANDLE...TOWARD THE DELMARVA AREA TODAY.
NOT A LOT OF CHANGES TO MAKE TO THE CURRENT FORECAST. AREAS OF
LIGHT RAIN OVER SPREADING THE AREA ARE CREATING AN IN-SITU COLD AIR
DAMMING AIRMASS AND STRENGTHENING THE STABILITY ACROSS THE CWA.
MODELS HAVE TRENDED A LITTLE EAST WITH THE TRACK OF THE SURFACE
LOW...ESPECIALLY THE GFS...THOUGH NOT AS MUCH AS ONE MIGHT EXPECT IF
THEY ARE CATCHING ONTO THE CAD AIRMASS. A CONSENSUS WOULD TRACK THE
LOW UP THE I-95 CORRIDOR BETWEEN 15Z AND 18Z. THE COASTAL WARM
FRONT AND 55-65F DEWPOINT AIR ALONG THE CAROLINA COAST WILL SURGE
INLAND AS PRESSURES BEGIN TO FALL...BUT IT APPEARS THE BETTER
MARITIME AIRMASS THAT WOULD LEAD TO BETTER DESTABILIZATION AND
SEVERE THREAT WILL STAY ALONG THE COAST...HINDERED BY THE STABLE CAD
AIRMASS. STILL..THERE MAY BE A BRIEF PERIOD (15-18Z) WHERE 250-500
J/KG OF NEAR SURFACE BASED CAPE CAN PHASE WITH HODOGRAPHS FAVORABLE
OF LOW-TOPPED ROTATING STORMS OVER THE COASTAL PLAIN. ON THE HEELS
OF THE SURFACE LOW...A BROKEN LINE OF SHOWERS SHOULD DEVELOP ALONG
THE WEAK COLD FRONT AND CONVERGENCE ZONE...WHICH COULD STILL PRODUCE
SOME STRONG WIND GUSTS VIA DOWNWARD MOMENTUM TRANSPORT ON THE TAIL
END OF THE LOW LEVEL JET.
CATEGORICAL POPS DURING THE FIRST HALF OF THE DAY WILL TREND DOWN
QUICKLY FROM SOUTHWEST TO NORTHEAST AFTER 18Z AND THE CWA WILL BE
COMPLETELY DRY BY 00Z. HARD TO GET A SOLID HANDLE ON QPF AMOUNTS AS
PRECIP IS JUST NOW BEGINNING TO FILL IN ACROSS THE CWA. THE FOCI
FOR HEAVIER PRECIP WILL BE THE LLJ ENHANCED ISENTROPIC ACCENT OVER
THE CAD COLD DOME IN THE WEST AND ALSO THE SURFACE LOW/FRONTAL
PRECIP BAND OVER THE COASTAL PLAIN. HOURLY RAINFALL RATES UPSTREAM
ARE AROUND 0.10" TO 0.25"...WHICH AGREE WELL WITH THE RAP AND HRRR.
BASED ON THIS...A WIDESPREAD 1-1.5" STILL SEEMS REASONABLE.
REGARDING TEMPS...THE CWA WILL BE SPLIT BY THE INLAND PUSH OF THE
WARM SECTOR...WITH MID AND UPPER 40S OVER THE WESTERN PIEDMONT AND
UPPER 50S TO POSSIBLE MID 60S OVER THE COASTAL PLAIN. THERE IS A
CHANCE THAT WESTERLY WIND AND PARTIAL CLEARING BEHIND THE FRONT MAY
ALLOW TEMPS IN THE TRIAD TO JUMP A COUPLE EXTRA DEGREES BEFORE
SUNSET.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
AS OF 250 AM SUNDAY...
IN THE WAKE OF THE DEPARTING LOW PRESSURE SYSTEM...LOW LEVEL
MOISTURE WILL SLOWLY SCOUR VIA A WESTERLY WIND SUNDAY EVENING/NIGHT.
CIRRUS SHOULD SPREAD BACK IN FROM THE SOUTHWEST OVERNIGHT AND DURING
THE DAY MONDAY AHEAD OF A WAVE MOVING THROUGH THE MEAN UPPER TROUGH.
A WEAKENING MSLP GRADIENT AND AT LEAST PARTIAL CLEARING MAY LEAD TO
FOG POTENTIAL...THOUGH CONFIDENCE IN THIS IS LOW AT THE MOMENT.
LOWS 36-41. HIGHS MONDAY 49-56. -SMITH
TROUGH AXIS MOVES THROUGH EARLY TUESDAY... AND A SURFACE WAVE
DEVELOPS ALONG THE FRONT OFF THE COAST... BRINGING A PERIOD OF LIGHT
PRECIP EARLY TUESDAY IN THE GFS AND NAM RUNS IN ASSOCIATION WITH AN
AREA OF FRONTOGENETICAL FORCING. AS MENTIONED IN PREVIOUS
DISCUSSION... PARTIAL THICKNESSES POINT TO THE POTENTIAL FOR SOME
SNOW TO MIX IN BRIEFLY TOWARD THE END OF THE PRECIPITATION IN THE
PIEDMONT DURING THE MORNING HOURS TUESDAY... AS STRONG COLD
ADVECTION MOVES IN TO THE AREA. HIGH TEMPERATURES IN THE LOW 40S.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 308 PM SATURDAY...
HIGH PRESSURE WILL BUILD IN TO THE SOUTHEAST ON WEDNESDAY.
SIGNIFICANT DIFFERENCES APPEARED IN PREVIOUS MODEL RUNS ON
THURSDAY... BUT MOST RECENT 12Z ECMWF RUN HAS COME CLOSER IN LINE
WITH THE GFS SOLUTION OF A STRONG WAVE DIGGING OVER THE OHIO VALLEY
ON THURSDAY. WILL CARRY SLIGHT CHANCE POPS FOR THE LATTER HALF OF
THURSDAY AT THIS POINT. HIGH PRESSURE WILL LIKELY BUILD IN BEHIND
THE DEPARTING SYSTEM ON SATURDAY. LOWS IN THE 20S TO LOW 30S WITH
HIGHS IN THE 40S DURING THIS PERIOD.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 1240 AM SUNDAY...
24 HOUR TAF PERIOD: AREAS OF LIGHT RAIN ARE SPREADING ACROSS CENTRAL
NC THIS MORNING AS A STORM SYSTEM BEGINS TO LIFT NORTHEAST FROM THE
GULF OF MEXICO. CEILINGS ARE MOSTLY MVFR AND VFR AT THE MOMENT BUT
WILL DROP RAPIDLY TO IFR AND LIFR BY 12Z AS MORE WIDESPREAD AND
HEAVIER RAIN OVERSPREADS THE AREA. AT THE SAME TIME...A
STRONG...SOUTHERLY LOW LEVEL JET OF AROUND 50KT WILL SURGE NORTH
ACROSS THE AREA...WHICH WILL LEAD TO A PERIOD OF LOW-LEVEL WIND
SHEAR THREAT DUE TO LIGHTER NORTHEASTERLY WINDS AT THE SURFACE. LOW-
LEVEL WIND SHEAR WILL BE MOST LIKELY BETWEEN 09Z AND
15Z...AFTERWHICH WINDS WILL START TO BECOME MORE UNIFORM OUT OF THE
SOUTHWEST AS THE STORM SYSTEM PULLS AWAY FROM THE AREA. GUSTY WINDS
WILL STILL BE POSSIBLE...ESPECIALLY IN THE EAST OF KRDU WHERE AN
ISOLATED THUNDER STORMS OR TWO IS POSSIBLE. PRECIP WILL COME TO AN
END FROM WEST TO EAST DUE THE AFTERNOON...WITH CEILINGS ALSO
SCATTERING AS WINDS BECOME MORE SOUTHWESTERLY.
LOOKING AHEAD: ANOTHER UPPER LEVEL DISTURBANCE WILL CROSS THE AREA
MONDAY NIGHT AND EARLY TUESDAY...POTENTIALLY GENERATING A FEW
SHOWERS AND A SHORT PERIOD OF SUB-VFR CEILINGS. FROM TUESDAY
AFTERNOON THROUGH EARLY THURSDAY EXPECT VFR CONDITIONS...WITH
ANOTHER POTENTIAL SHOT OF SOME RAIN THURSDAY AFT/EVE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...SMITH/SEC
LONG TERM...SEC
AVIATION...KC/SMITH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
249 PM CST SUN DEC 29 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 248 PM CST SUN DEC 29 2013
FORECAST CHALLENGE TONIGHT WILL BE EASTWARD EXTEND OF CLOUDS OVER
CENTRAL NORTH DAKOTA AND THEIR IMPACT ON TEMPS AND WIND CHILL
HEADLINES. OVERALL CLOUDS ADVECTING EAST QUICKER THAN INITIALLY
THOUGHT...AND MAY MAKE DEVILS LAKE BY 00Z. MODELS HAVE STRUGGLED
TO WITH PICKING UP ON THE MOISTURE...MAINLY HIGHLIGHTING THE
HIGHER CLOUDS OVER MINOT AND WEST. USING MAINLY SATELLITE TRENDS
FOR THE NEAR TERM AND MORE OF A ECMWF/NAM BLEND FOR THE EARLY PART
OF THE WEEK.
TONIGHT...CLOUDS WILL SLOWLY SPREAD INTO EASTERN ND AND APPROACH
THE RRV BY MIDNIGHT. A RATHER BULLISH CROSS SECTION FROM RUGBY TO
GRAND FORKS BRINGS CLOUDS INTO GFK BY 03Z..WHICH I THINK IS A BIT
TOO FAST. AS STATED PREVIOUSLY...MODELS ARE STRUGGLING WITH
ESPECIALLY THE LOWER CLOUDS THAT WERE PRESENT EARLY THIS MORNING.
THE RAP AVIATION FLIGHT RULES PRODUCT BRINGS THE LOW CLOUDS INTO
THE VALLEY AROUND THE 06Z/07Z TIME FRAME...BUT MID CLOUD SHOULD
ARRIVE PRIOR TO THAT. SO THE QUESTION BECOMES HOW FAST WILL TEMPS
DROP OFF AS THE SUN ANGLE DECREASES IN THE LATE AFTN...AND THEIR
IS ENOUGH WIND TO KEEP US IN ADVISORY CRITERIA THROUGH CURRENTLY
ADVERTISED TIMES. WILL NOT MAKE ANY CHANGES TO HEADLINES AT THIS
POINT BUT MAY SEE ADVISORY CANCELLED ACROSS EASTERN ND WELL AHEAD
OF SCHEDULE IF CLOUDS CAN LEVEL OFF THE TEMP CURVE QUICK ENOUGH.
OTHER ISSUE IS THAT WINDS ARE RATHER LIGHT...BUT ONLY TAKES 2 TO 3
KNOTS IN THE COLDEST AIR TO GET APPARENT TEMPS IN ADVISORY
CRITERIA. AGAIN...WILL KEEP HEADLINES IN PLACE AS IT IS GOING TO
BE DARN COLD TONIGHT WITHIN AND EAST OF THE VALLEY.
TOMORROW AND TOMORROW NIGHT...A WEAK WAVE WILL MOVE ACROSS CENTRAL
DAKOTAS AND SHOULD RESULT IN A BAND OF VERY DRY FLUFF ACROSS THE
CENTRAL PART OF THE STATE. THIS MAY CLIP THE SHEYENNE
VALLEY...WITH THE BEST CHANCES FOR UP TO TWO INCHES OF FLUFF BEING
FROM EDDY DOWN TO RANSOM/SARGENT COUNTIES. EXPECT SNOWFALL TO BE
INTO MAINLY WEST CENTRAL MN AFTER NOON...AND OUT OF THE REGION BY
EARLY MONDAY EVENING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 248 PM CST SUN DEC 29 2013
TUESDAY AND WEDNESDAY...A SERIES OF WAVES EMBEDDED IN THE NW FLOW
PATTERN WILL BRING MORE CHANCES OF LIGHT SNOW MAINLY IN THE FAR
WEST ON TUE AND WED. THE WED SYSTEM...ALTHOUGH WEAKER AND
DRIER...SHOULD GIVE OUR CWA A LITTLE BETTER CHANCE AS THE UPPER
PATTERN SHIFTS EAST AND THE TRACK OF THE WAVES MOVES FROM THE
CENTRAL TO THE EASTERN DAKOTAS. EACH WAVE WILL GENERALLY BE MORE
DRY FLUFF THAT MAY ACCUMULATE AN INCH OR TWO DUE TO HIGH SNOWFALL
RATIOS WITH VERY LITTLE LIQUID EQUIVALENT.
WEDNESDAY NIGHT-SUNDAY...MODELS ARE IN GOOD AGREEMENT. THE PERIOD
STARTS WITH THE REGION IN NORTHWEST FLOW ALOFT...ALONG WITH HIGH
PRESSURE AND VERY COLD TEMPERATURES. THE UPPER PATTERN THEN
DEAMPLIFIES...ALLOWING ZONAL FLOW BY THE WEEKEND. THIS WILL LEAD TO
MUCH WARMER TEMPERATURES ON FRIDAY. A SYSTEM WILL MOVE THROUGH
SOUTHERN CANADA...SENDING A COLD FRONT THROUGH THE FA LATE FRIDAY OR
EARLY SATURDAY. LIGHT SNOW AND WINDY CONDITIONS POSSIBLE WITH THIS
FEATURE...ALTHOUGH DETAILS ARE FUZZY. TEMPERATURES WILL BE A BIT
COOLER FOR THE WEEKEND (COMPARED TO FRIDAY). MODELS SHOW A MUCH
STRONGER COLD FRONT POSSIBLE FOR LATER SUNDAY OR EARLY MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 105 PM CST SUN DEC 29 2013
HIGH PRESSURE WILL LEAD TO MOSTLY CLEAR SKIES THROUGH AT LEAST THE
FIRST HALF OF THIS PERIOD. A CLIPPER SYSTEM WILL BRING MID-LEVEL
CLOUDS INTO THE REGION FROM WEST TO EAST DURING THE SECOND HALF OF
THIS PERIOD...WITH -SN AND MVFR CONDITIONS LIKELY AFFECTING KDVL AND
KFAR MONDAY MORNING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND CHILL ADVISORY UNTIL 9 PM CST THIS EVENING FOR NDZ038-049-
052.
WIND CHILL ADVISORY UNTIL 6 AM CST MONDAY FOR NDZ008-016-027-029-
030-039-053.
WIND CHILL ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ006-007-
014-015-024-026-028-054.
MN...WIND CHILL ADVISORY UNTIL 6 AM CST MONDAY FOR MNZ001>009-013>017-
022>024-027>032-040.
&&
$$
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1128 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 1130 AM CST SUN DEC 29 2013
MAIN UPDATES WERE TO CANCEL ADDITIONAL PORTIONS OF WIND CHILL
ADVISORY AND TO REPLACE THE WIND CHILL WARNING ALONG OUR FAR
EASTERN COUNTIES WITH A WIND CHILL ADVISORY. ALSO ADJUSTED SKY
COVER TO ACCOUNT FOR SLOWLY EXPANDING CLOUD FIELD THAT IS SLOWLY
PUSHING EASTWARD. EASTERN EDGE OF CLOUDS RUNS APPROXIMATELY FROM
BOTTINEAU COUNTY SOUTHWARD THROUGH SHERIDAN...KIDDER...LOGAN AND
MCINTOSH COUNTIES. AREAS EAST OF THIS LINE CONTINUE TO SEE WIND
CHILLS VALUES FROM 25 BELOW TO 35 BELOW ZERO. OTHERWISE...FORECAST
REMAINS ON TRACK WITH NEXT QUICK MOVING CLIPPER THAT WILL SPREAD
SNOW FROM NORTHWEST TO SOUTHEAST LATE TODAY INTO MONDAY MORNING.
12Z NAM SEEMS A LITTLE FASTER THAN GFS AND 00Z ECMWF ALTHOUGH
AREAL COVERAGE IS SIMILAR AMONG ALL 3 MODELS AND THE SREF.
UPDATE ISSUED AT 900 AM CST SUN DEC 29 2013
CLOUDS ACROSS WESTERN ND HAVE REMAINED IN PLACE WITH TEMPERATURES
AROUND ZERO AND WIND CHILL VALUES ABOVE ADVISORY CRITERIA...SO
HAVE CANCELLED WIND CHILL ADVISORY FOR THIS AREA. WIND CHILLS
IMMEDIATELY EAST OF CLOUDS REMAIN IN ADVISORY/WARNING RANGE AND
HAVE CONTINUED THE HEADLINES THERE. OTHERWISE...FORECAST REMAINS
ON TRACK.
UPDATE ISSUED AT 639 AM CST SUN DEC 29 2013
MID LEVEL CLOUDS OVER WESTERN NORTH DAKOTA THIS MORNING MORE
EXPANSIVE THAN MODELS FORECAST AT 700MB....BUT MOISTURE AT H850 IN
MODELS...JUST NOT SHOWING UP AT THAT LEVEL. KEPT CLOUDS IN FORECAST
WEST INTO CENTRAL. ALTHOUGH WIND CHILLS JUST A BIT OUT OF CATEGORY
WEST ANY BUT OF WIND WILL LOWER INTO CATEGORY.
UPDATE
ISSUED AT 550 AM CST SUN DEC 29 2013
QUICK UPDATE TO ACCOUNT FOR LINGERING LARGE AREA OF BKN-OVC CIGS
ACROSS WESTERN NORTH DAKOTA. AS MENTIONED BELOW...MODELS ARE
POORLY DEPICTING THESE CLOUDS...WHICH GREATLY AFFECT THIS MORNINGS
TEMPERATURES FORECAST. THE LATEST RAP APPEARS TO HINT AT THESE
CLOUDS...WHICH HOLD TOGETHER WELL INTO THIS MORNING. THUS
INCREASED SKY COVER WEST AND WARMED TEMPERATURES NEAR TO
UNDERNEATH THE CLOUDS. STILL COLD WHERE SKIES HAVE GONE
CLEAR...AROUND 25 BELOW AND PERHAPS COLDER WITH DEWPOINTS NEARING
30 BELOW.
&&
.SHORT TERM...(THIS MORNING THROUGH TONIGHT)
ISSUED AT 411 AM CST SUN DEC 29 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE VERY COLD
TEMPERATURES THIS MORNING AND AFTERNOON...FOLLOWED BY A SHOT OF
LIGHT ACCUMULATING SNOW FOR TONIGHT.
CURRENTLY...ARCTIC HIGH PRESSURE CONTINUES SOUTH INTO NORTH
DAKOTA EARLY THIS MORNING...RESULTING IN A RAPIDLY CLEARING SKY
ACROSS MY NORTH CENTRAL SPREADING SOUTHWARD. MODELS FAILED TO PICK
UP ON A RATHER LARGE AREA OF 4-5K FOOT AGL CIGS FROM FAR SOUTH
CENTRAL SASKATCHEWAN EXTENDING SOUTHEAST INTO NORTHWESTERN NORTH
DAKOTA. IT IS UNCLEAR IF THESE CLOUDS WILL CLEAR OUT AT ALL WITH
RETURN FLOW DEVELOPING AFTER 12Z THIS MORNING AND INCREASING
CLOUDS EXPECTED FROM THE WEST. BUFFER SOUNDINGS DO SHOW A GRADUAL
SCATTERING OUT AFTER SUNRISE AS THE TOP OF THE CLOUD LAYER
DE-SATURATES DOWNWARD...SO DID TREND SKY COVER FOR THIS AREA TO
SCATTERED/MOSTLY SUNNY 12-15Z THIS MORNING.
AS THE SKY CLEARS AND WINDS CONTINUE TO SUBSIDE UNDERNEATH THE
ARCTIC HIGH...TEMPERATURES WILL RAPIDLY PLUMMET. ALREADY NEAR 15
BELOW OVER MY FAR NORTH CENTRAL...AND EXPECT LOWS OF 20 BELOW TO
NEAR 25 BELOW ZERO ACROSS PORTIONS OF CENTRAL NORTH DAKOTA THROUGH
8-9AM SUNDAY. WARMER SOUTHWEST AROUND 5 BELOW WHERE LINGERING
CLOUDS ARE FORECAST. WIND CHILL HEADLINES LOOK FINE AND WILL MAKE
NO CHANGES WITH THIS FORECAST ISSUANCE.
COLD START OF THE DAY WILL RESULT IN SUBZERO HIGHS OVER MY CENTRAL
(NEAR -5F) AND MY EAST (NEAR -10F). BETTER SOUTHERLY RETURN FLOW
AND WAA ACROSS MY SOUTHWEST WHERE WE HAVE FORECAST HIGHS AROUND
10F ABOVE ZERO.
ACTIVE WEATHER PATTERN CONTINUES AS ANOTHER CLIPPER TRACKS
SOUTHEAST ACROSS THE NORTHERN PLAINS TONIGHT. UPPER LEVEL 125KT
JET STREAK NOW RIDING OVER THE UPPER LEVEL RIDGE PARKED OFF THE
WEST COAST WILL MOVE SOUTHEAST TONIGHT TO OVER THE NORTHERN HIGH
PLAINS OF MT/WY. THIS FEATURE WILL DRIVE A MID LEVEL IMPULSE AND
ASSOCIATED SURFACE LOW FROM EASTERN MONTANA THIS EVENING
SOUTHEAST INTO CENTRAL SOUTH DAKOTA AFTER MIDNIGHT. THE TRACK OF
THIS LOW AND PLACEMENT OF UPPER LEVEL DIVERGENCE WILL FAVOR
PRECIPITATION DEVELOPING ACROSS THE NORTHWEST THIS EVENING...THEN
SPREADING EAST-SOUTHEAST LATE SUNDAY NIGHT ACROSS CENTRAL ND AND
EVENTUALLY INTO THE JAMES RIVER BASIN AND SOUTHERN RED RIVER
VALLEY MONDAY MORNING. THANKS TO SNOW RATIOS RANGING FROM 15:1 TO
20:1...MAY SEE IN INCH TO AN INCH AND ONE HALF OF SNOW BY MONDAY
MORNING ALONG THE ABOVE MENTIONED TRACK...ROUGHLY ACROSS THE
NORTHWEST QUARTER OF THE STATE SOUTHEAST THROUGH MINOT AND
BISMARCK AND THROUGH THE JAMES RIVER BASIN.
WHILE WINDS WILL TRANSITION TO NORTH/NORTHWEST BEHIND THIS
CLIPPER AND INCREASE SOME...GRADIENT FORCING AND PRESSURE RISES
RATHER WEAK SO AM NOT ANTICIPATING MUCH BLOWING SNOW POTENTIAL AT
THIS TIME.
ONE MORE THING OF NOTE...EXPECT TEMPERATURES TO WARM THIS EVENING
ESPECIALLY SOUTHWEST INTO SOUTH CENTRAL WHERE THE BEST WAA WILL
OCCUR TONIGHT AHEAD OF THE LOW BEFORE CAA OVERTAKES US FOR MONDAY
DAYTIME. THUS EXPECT TO SEE TODAYS HIGH TEMPERATURES REACHED MANY
LOCATIONS SOMETIME THIS SUNDAY EVENING...AND MONDAYS HIGHS MOST
LIKELY SOMETIME AFTER MIDNIGHT THROUGH MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 411 AM CST SUN DEC 29 2013
MODELS CONTINUE THE TREND OF A COLD UPPER LOW OVER CENTRAL CANADA
REMAINING QUASI STATIONARY...ALBEIT MEANDERING A BIT...DURING THE
EXTENDED FORECAST PERIOD. AT THE SAME TIME...EASTERN PACIFIC RIDGING
REMAINS IN PLACE FEEDING MILDER TEMPERATURES TO THE WESTERN US.
ACROSS THE NORTHERN PLAINS...THE BATTLE BETWEEN THE WARM AND COLD
WILL BRING AN ACTIVE WEATHER PATTERN TO THE REGION. TUESDAY AND
WEDNESDAY MORNINGS SHOULD REMAIN QUITE COLD...WITH LOWS AS COLD AS
THE MID 20S BELOW ACROSS THE NORTH CENTRAL. COLD WIND CHILLS WILL
AGAIN BE FEATURED AT THIS TIME ESPECIALLY ALONG THE CANADIAN BORDER.
THEN A SHORTWAVE WILL MOVE ACROSS THE NORTHERN PLAINS AND BRING A
CHANCE OF SNOW THROUGH THE FIRST HALF OF THE PERIOD. ACCUMULATING
SNOW APPEARS LIKELY TUESDAY AND WEDNESDAY. AFTER WEDNESDAY...THE
ARCTIC AIR GETS NUDGED BACK NORTH AND MODERATING TEMPERATURES...
ESPECIALLY BY FRIDAY AND SATURDAY MAKE THERE WAY BACK TO NORTH
DAKOTA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 639 AM CST SUN DEC 29 2013
BKN-OVC MID LEVEL CLOUDS WILL PERSIST THROUGH SUNDAY MORNING AND
WEST AND DRIFT SLOWLY EASTWARD INTO THE CENTRAL ASSOCIATED WITH
WEAK WARM ADVECTION IMPACTING KISN-KDIK-KMOT-KBIS. OVERALL...VFR
FLIGHT CONDITIONS EXPECTED THROUGH SUNDAY AFTERNOON. ANOTHER
CLIPPER STORM SYSTEM WILL MOVE SOUTHEAST INTO THE DAKOTAS SUNDAY
EVENING OVERNIGHT INTO MONDAY MORNING. EXPECT TO SEE DETERIORATING
FLIGHT CONDITIONS WEST SUNDAY EVENING IMPACTING KISN AND
KDIK...THEN EASTWARD LATER SUNDAY NIGHT IMPACTING KBIS-KMOT- KJMS.
CIGS ARE FORECAST TO DROP TO MVFR AND VIS IN FALLING SNOW FALLING
TO IFR AND POSSIBLY LOWER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 9 PM CST THIS EVENING FOR NDZ037-048-
051.
WIND CHILL ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ005-013-
023-025.
&&
$$
UPDATE...JNS
SHORT TERM...NH
LONG TERM...WAA
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
859 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 900 AM CST SUN DEC 29 2013
CLOUDS ACROSS WESTERN ND HAVE REMAINED IN PLACE WITH TEMPERATURES
AROUND ZERO AND WIND CHILL VALUES ABOVE ADVISORY CRITERIA...SO
HAVE CANCELLED WIND CHILL ADVISORY FOR THIS AREA. WIND CHILLS
IMMEDIATELY EAST OF CLOUDS REMAIN IN ADVISORY/WARNING RANGE AND
HAVE CONTINUED THE HEADLINES THERE. OTHERWISE...FORECAST REMAINS
ON TRACK.
UPDATE ISSUED AT 639 AM CST SUN DEC 29 2013
MID LEVEL CLOUDS OVER WESTERN NORTH DAKOTA THIS MORNING MORE
EXPANSIVE THAN MODELS FORECAST AT 700MB....BUT MOISTURE AT H850 IN
MODELS...JUST NOT SHOWING UP AT THAT LEVEL. KEPT CLOUDS IN FORECAST
WEST INTO CENTRAL. ALTHOUGH WIND CHILLS JUST A BIT OUT OF CATEGORY
WEST ANY BUT OF WIND WILL LOWER INTO CATEGORY.
UPDATE
ISSUED AT 550 AM CST SUN DEC 29 2013
QUICK UPDATE TO ACCOUNT FOR LINGERING LARGE AREA OF BKN-OVC CIGS
ACROSS WESTERN NORTH DAKOTA. AS MENTIONED BELOW...MODELS ARE
POORLY DEPICTING THESE CLOUDS...WHICH GREATLY AFFECT THIS MORNINGS
TEMPERATURES FORECAST. THE LATEST RAP APPEARS TO HINT AT THESE
CLOUDS...WHICH HOLD TOGETHER WELL INTO THIS MORNING. THUS
INCREASED SKY COVER WEST AND WARMED TEMPERATURES NEAR TO
UNDERNEATH THE CLOUDS. STILL COLD WHERE SKIES HAVE GONE
CLEAR...AROUND 25 BELOW AND PERHAPS COLDER WITH DEWPOINTS NEARING
30 BELOW.
&&
.SHORT TERM...(THIS MORNING THROUGH TONIGHT)
ISSUED AT 411 AM CST SUN DEC 29 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE VERY COLD
TEMPERATURES THIS MORNING AND AFTERNOON...FOLLOWED BY A SHOT OF
LIGHT ACCUMULATING SNOW FOR TONIGHT.
CURRENTLY...ARCTIC HIGH PRESSURE CONTINUES SOUTH INTO NORTH
DAKOTA EARLY THIS MORNING...RESULTING IN A RAPIDLY CLEARING SKY
ACROSS MY NORTH CENTRAL SPREADING SOUTHWARD. MODELS FAILED TO PICK
UP ON A RATHER LARGE AREA OF 4-5K FOOT AGL CIGS FROM FAR SOUTH
CENTRAL SASKATCHEWAN EXTENDING SOUTHEAST INTO NORTHWESTERN NORTH
DAKOTA. IT IS UNCLEAR IF THESE CLOUDS WILL CLEAR OUT AT ALL WITH
RETURN FLOW DEVELOPING AFTER 12Z THIS MORNING AND INCREASING
CLOUDS EXPECTED FROM THE WEST. BUFFER SOUNDINGS DO SHOW A GRADUAL
SCATTERING OUT AFTER SUNRISE AS THE TOP OF THE CLOUD LAYER
DE-SATURATES DOWNWARD...SO DID TREND SKY COVER FOR THIS AREA TO
SCATTERED/MOSTLY SUNNY 12-15Z THIS MORNING.
AS THE SKY CLEARS AND WINDS CONTINUE TO SUBSIDE UNDERNEATH THE
ARCTIC HIGH...TEMPERATURES WILL RAPIDLY PLUMMET. ALREADY NEAR 15
BELOW OVER MY FAR NORTH CENTRAL...AND EXPECT LOWS OF 20 BELOW TO
NEAR 25 BELOW ZERO ACROSS PORTIONS OF CENTRAL NORTH DAKOTA THROUGH
8-9AM SUNDAY. WARMER SOUTHWEST AROUND 5 BELOW WHERE LINGERING
CLOUDS ARE FORECAST. WIND CHILL HEADLINES LOOK FINE AND WILL MAKE
NO CHANGES WITH THIS FORECAST ISSUANCE.
COLD START OF THE DAY WILL RESULT IN SUBZERO HIGHS OVER MY CENTRAL
(NEAR -5F) AND MY EAST (NEAR -10F). BETTER SOUTHERLY RETURN FLOW
AND WAA ACROSS MY SOUTHWEST WHERE WE HAVE FORECAST HIGHS AROUND
10F ABOVE ZERO.
ACTIVE WEATHER PATTERN CONTINUES AS ANOTHER CLIPPER TRACKS
SOUTHEAST ACROSS THE NORTHERN PLAINS TONIGHT. UPPER LEVEL 125KT
JET STREAK NOW RIDING OVER THE UPPER LEVEL RIDGE PARKED OFF THE
WEST COAST WILL MOVE SOUTHEAST TONIGHT TO OVER THE NORTHERN HIGH
PLAINS OF MT/WY. THIS FEATURE WILL DRIVE A MID LEVEL IMPULSE AND
ASSOCIATED SURFACE LOW FROM EASTERN MONTANA THIS EVENING
SOUTHEAST INTO CENTRAL SOUTH DAKOTA AFTER MIDNIGHT. THE TRACK OF
THIS LOW AND PLACEMENT OF UPPER LEVEL DIVERGENCE WILL FAVOR
PRECIPITATION DEVELOPING ACROSS THE NORTHWEST THIS EVENING...THEN
SPREADING EAST-SOUTHEAST LATE SUNDAY NIGHT ACROSS CENTRAL ND AND
EVENTUALLY INTO THE JAMES RIVER BASIN AND SOUTHERN RED RIVER
VALLEY MONDAY MORNING. THANKS TO SNOW RATIOS RANGING FROM 15:1 TO
20:1...MAY SEE IN INCH TO AN INCH AND ONE HALF OF SNOW BY MONDAY
MORNING ALONG THE ABOVE MENTIONED TRACK...ROUGHLY ACROSS THE
NORTHWEST QUARTER OF THE STATE SOUTHEAST THROUGH MINOT AND
BISMARCK AND THROUGH THE JAMES RIVER BASIN.
WHILE WINDS WILL TRANSITION TO NORTH/NORTHWEST BEHIND THIS
CLIPPER AND INCREASE SOME...GRADIENT FORCING AND PRESSURE RISES
RATHER WEAK SO AM NOT ANTICIPATING MUCH BLOWING SNOW POTENTIAL AT
THIS TIME.
ONE MORE THING OF NOTE...EXPECT TEMPERATURES TO WARM THIS EVENING
ESPECIALLY SOUTHWEST INTO SOUTH CENTRAL WHERE THE BEST WAA WILL
OCCUR TONIGHT AHEAD OF THE LOW BEFORE CAA OVERTAKES US FOR MONDAY
DAYTIME. THUS EXPECT TO SEE TODAYS HIGH TEMPERATURES REACHED MANY
LOCATIONS SOMETIME THIS SUNDAY EVENING...AND MONDAYS HIGHS MOST
LIKELY SOMETIME AFTER MIDNIGHT THROUGH MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 411 AM CST SUN DEC 29 2013
MODELS CONTINUE THE TREND OF A COLD UPPER LOW OVER CENTRAL CANADA
REMAINING QUASI STATIONARY...ALBEIT MEANDERING A BIT...DURING THE
EXTENDED FORECAST PERIOD. AT THE SAME TIME...EASTERN PACIFIC RIDGING
REMAINS IN PLACE FEEDING MILDER TEMPERATURES TO THE WESTERN US.
ACROSS THE NORTHERN PLAINS...THE BATTLE BETWEEN THE WARM AND COLD
WILL BRING AN ACTIVE WEATHER PATTERN TO THE REGION. TUESDAY AND
WEDNESDAY MORNINGS SHOULD REMAIN QUITE COLD...WITH LOWS AS COLD AS
THE MID 20S BELOW ACROSS THE NORTH CENTRAL. COLD WIND CHILLS WILL
AGAIN BE FEATURED AT THIS TIME ESPECIALLY ALONG THE CANADIAN BORDER.
THEN A SHORTWAVE WILL MOVE ACROSS THE NORTHERN PLAINS AND BRING A
CHANCE OF SNOW THROUGH THE FIRST HALF OF THE PERIOD. ACCUMULATING
SNOW APPEARS LIKELY TUESDAY AND WEDNESDAY. AFTER WEDNESDAY...THE
ARCTIC AIR GETS NUDGED BACK NORTH AND MODERATING TEMPERATURES...
ESPECIALLY BY FRIDAY AND SATURDAY MAKE THERE WAY BACK TO NORTH
DAKOTA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 639 AM CST SUN DEC 29 2013
BKN-OVC MID LEVEL CLOUDS WILL PERSIST THROUGH SUNDAY MORNING AND
WEST AND DRIFT SLOWLY EASTWARD INTO THE CENTRAL ASSOCIATED WITH
WEAK WARM ADVECTION IMPACTING KISN-KDIK-KMOT-KBIS. OVERALL...VFR
FLIGHT CONDITIONS EXPECTED THROUGH SUNDAY AFTERNOON. ANOTHER
CLIPPER STORM SYSTEM WILL MOVE SOUTHEAST INTO THE DAKOTAS SUNDAY
EVENING OVERNIGHT INTO MONDAY MORNING. EXPECT TO SEE DETERIORATING
FLIGHT CONDITIONS WEST SUNDAY EVENING IMPACTING KISN AND
KDIK...THEN EASTWARD LATER SUNDAY NIGHT IMPACTING KBIS-KMOT- KJMS.
CIGS ARE FORECAST TO DROP TO MVFR AND VIS IN FALLING SNOW FALLING
TO IFR AND POSSIBLY LOWER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR NDZ021-035-
046.
WIND CHILL WARNING UNTIL 1 PM CST THIS AFTERNOON FOR NDZ003>005-
011>013-022-023-025-036-037-047-048-050-051.
&&
$$
UPDATE...JNS
SHORT TERM...NH
LONG TERM...WAA
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
647 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 639 AM CST SUN DEC 29 2013
MID LEVEL CLOUDS OVER WESTERN NORTH DAKOTA THIS MORNING MORE
EXPANSIVE THAN MODELS FORECAST AT 700MB....BUT MOISTURE AT H850 IN
MODELS...JUST NOT SHOWING UP AT THAT LEVEL. KEPT CLOUDS IN FORECAST
WEST INTO CENTRAL. ALTHOUGH WIND CHILLS JUST A BIT OUT OF CATEGORY
WEST ANY BUT OF WIND WILL LOWER INTO CATEGORY.
UPDATE
ISSUED AT 550 AM CST SUN DEC 29 2013
QUICK UPDATE TO ACCOUNT FOR LINGERING LARGE AREA OF BKN-OVC CIGS
ACROSS WESTERN NORTH DAKOTA. AS MENTIONED BELOW...MODELS ARE
POORLY DEPICTING THESE CLOUDS...WHICH GREATLY AFFECT THIS MORNINGS
TEMPERATURES FORECAST. THE LATEST RAP APPEARS TO HINT AT THESE
CLOUDS...WHICH HOLD TOGETHER WELL INTO THIS MORNING. THUS
INCREASED SKY COVER WEST AND WARMED TEMPERATURES NEAR TO
UNDERNEATH THE CLOUDS. STILL COLD WHERE SKIES HAVE GONE
CLEAR...AROUND 25 BELOW AND PERHAPS COLDER WITH DEWPOINTS NEARING
30 BELOW.
&&
.SHORT TERM...(THIS MORNING THROUGH TONIGHT)
ISSUED AT 411 AM CST SUN DEC 29 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE VERY COLD
TEMPERATURES THIS MORNING AND AFTERNOON...FOLLOWED BY A SHOT OF
LIGHT ACCUMULATING SNOW FOR TONIGHT.
CURRENTLY...ARCTIC HIGH PRESSURE CONTINUES SOUTH INTO NORTH
DAKOTA EARLY THIS MORNING...RESULTING IN A RAPIDLY CLEARING SKY
ACROSS MY NORTH CENTRAL SPREADING SOUTHWARD. MODELS FAILED TO PICK
UP ON A RATHER LARGE AREA OF 4-5K FOOT AGL CIGS FROM FAR SOUTH
CENTRAL SASKATCHEWAN EXTENDING SOUTHEAST INTO NORTHWESTERN NORTH
DAKOTA. IT IS UNCLEAR IF THESE CLOUDS WILL CLEAR OUT AT ALL WITH
RETURN FLOW DEVELOPING AFTER 12Z THIS MORNING AND INCREASING
CLOUDS EXPECTED FROM THE WEST. BUFFER SOUNDINGS DO SHOW A GRADUAL
SCATTERING OUT AFTER SUNRISE AS THE TOP OF THE CLOUD LAYER
DE-SATURATES DOWNWARD...SO DID TREND SKY COVER FOR THIS AREA TO
SCATTERED/MOSTLY SUNNY 12-15Z THIS MORNING.
AS THE SKY CLEARS AND WINDS CONTINUE TO SUBSIDE UNDERNEATH THE
ARCTIC HIGH...TEMPERATURES WILL RAPIDLY PLUMMET. ALREADY NEAR 15
BELOW OVER MY FAR NORTH CENTRAL...AND EXPECT LOWS OF 20 BELOW TO
NEAR 25 BELOW ZERO ACROSS PORTIONS OF CENTRAL NORTH DAKOTA THROUGH
8-9AM SUNDAY. WARMER SOUTHWEST AROUND 5 BELOW WHERE LINGERING
CLOUDS ARE FORECAST. WIND CHILL HEADLINES LOOK FINE AND WILL MAKE
NO CHANGES WITH THIS FORECAST ISSUANCE.
COLD START OF THE DAY WILL RESULT IN SUBZERO HIGHS OVER MY CENTRAL
(NEAR -5F) AND MY EAST (NEAR -10F). BETTER SOUTHERLY RETURN FLOW
AND WAA ACROSS MY SOUTHWEST WHERE WE HAVE FORECAST HIGHS AROUND
10F ABOVE ZERO.
ACTIVE WEATHER PATTERN CONTINUES AS ANOTHER CLIPPER TRACKS
SOUTHEAST ACROSS THE NORTHERN PLAINS TONIGHT. UPPER LEVEL 125KT
JET STREAK NOW RIDING OVER THE UPPER LEVEL RIDGE PARKED OFF THE
WEST COAST WILL MOVE SOUTHEAST TONIGHT TO OVER THE NORTHERN HIGH
PLAINS OF MT/WY. THIS FEATURE WILL DRIVE A MID LEVEL IMPULSE AND
ASSOCIATED SURFACE LOW FROM EASTERN MONTANA THIS EVENING
SOUTHEAST INTO CENTRAL SOUTH DAKOTA AFTER MIDNIGHT. THE TRACK OF
THIS LOW AND PLACEMENT OF UPPER LEVEL DIVERGENCE WILL FAVOR
PRECIPITATION DEVELOPING ACROSS THE NORTHWEST THIS EVENING...THEN
SPREADING EAST-SOUTHEAST LATE SUNDAY NIGHT ACROSS CENTRAL ND AND
EVENTUALLY INTO THE JAMES RIVER BASIN AND SOUTHERN RED RIVER
VALLEY MONDAY MORNING. THANKS TO SNOW RATIOS RANGING FROM 15:1 TO
20:1...MAY SEE IN INCH TO AN INCH AND ONE HALF OF SNOW BY MONDAY
MORNING ALONG THE ABOVE MENTIONED TRACK...ROUGHLY ACROSS THE
NORTHWEST QUARTER OF THE STATE SOUTHEAST THROUGH MINOT AND
BISMARCK AND THROUGH THE JAMES RIVER BASIN.
WHILE WINDS WILL TRANSITION TO NORTH/NORTHWEST BEHIND THIS
CLIPPER AND INCREASE SOME...GRADIENT FORCING AND PRESSURE RISES
RATHER WEAK SO AM NOT ANTICIPATING MUCH BLOWING SNOW POTENTIAL AT
THIS TIME.
ONE MORE THING OF NOTE...EXPECT TEMPERATURES TO WARM THIS EVENING
ESPECIALLY SOUTHWEST INTO SOUTH CENTRAL WHERE THE BEST WAA WILL
OCCUR TONIGHT AHEAD OF THE LOW BEFORE CAA OVERTAKES US FOR MONDAY
DAYTIME. THUS EXPECT TO SEE TODAYS HIGH TEMPERATURES REACHED MANY
LOCATIONS SOMETIME THIS SUNDAY EVENING...AND MONDAYS HIGHS MOST
LIKELY SOMETIME AFTER MIDNIGHT THROUGH MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 411 AM CST SUN DEC 29 2013
MODELS CONTINUE THE TREND OF A COLD UPPER LOW OVER CENTRAL CANADA
REMAINING QUASI STATIONARY...ALBEIT MEANDERING A BIT...DURING THE
EXTENDED FORECAST PERIOD. AT THE SAME TIME...EASTERN PACIFIC RIDGING
REMAINS IN PLACE FEEDING MILDER TEMPERATURES TO THE WESTERN US.
ACROSS THE NORTHERN PLAINS...THE BATTLE BETWEEN THE WARM AND COLD
WILL BRING AN ACTIVE WEATHER PATTERN TO THE REGION. TUESDAY AND
WEDNESDAY MORNINGS SHOULD REMAIN QUITE COLD...WITH LOWS AS COLD AS
THE MID 20S BELOW ACROSS THE NORTH CENTRAL. COLD WIND CHILLS WILL
AGAIN BE FEATURED AT THIS TIME ESPECIALLY ALONG THE CANADIAN BORDER.
THEN A SHORTWAVE WILL MOVE ACROSS THE NORTHERN PLAINS AND BRING A
CHANCE OF SNOW THROUGH THE FIRST HALF OF THE PERIOD. ACCUMULATING
SNOW APPEARS LIKELY TUESDAY AND WEDNESDAY. AFTER WEDNESDAY...THE
ARCTIC AIR GETS NUDGED BACK NORTH AND MODERATING TEMPERATURES...
ESPECIALLY BY FRIDAY AND SATURDAY MAKE THERE WAY BACK TO NORTH
DAKOTA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 639 AM CST SUN DEC 29 2013
BKN-OVC MID LEVEL CLOUDS WILL PERSIST THROUGH SUNDAY MORNING AND
WEST AND DRIFT SLOWLY EASTWARD INTO THE CENTRAL ASSOCIATED WITH
WEAK WARM ADVECTION IMPACTING KISN-KDIK-KMOT-KBIS. OVERALL...VFR
FLIGHT CONDITIONS EXPECTED THROUGH SUNDAY AFTERNOON. ANOTHER
CLIPPER STORM SYSTEM WILL MOVE SOUTHEAST INTO THE DAKOTAS SUNDAY
EVENING OVERNIGHT INTO MONDAY MORNING. EXPECT TO SEE DETERIORATING
FLIGHT CONDITIONS WEST SUNDAY EVENING IMPACTING KISN AND
KDIK...THEN EASTWARD LATER SUNDAY NIGHT IMPACTING KBIS-KMOT- KJMS.
CIGS ARE FORECAST TO DROP TO MVFR AND VIS IN FALLING SNOW FALLING
TO IFR AND POSSIBLY LOWER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 1 PM CST /NOON MST/ THIS AFTERNOON FOR
NDZ001-009-010-017>021-031>035-040>046.
WIND CHILL WARNING UNTIL 1 PM CST THIS AFTERNOON FOR NDZ002>005-
011>013-022-023-025-036-037-047-048-050-051.
&&
$$
UPDATE...WAA
SHORT TERM...NH
LONG TERM...WAA
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
550 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 550 AM CST SUN DEC 29 2013
QUICK UPDATE TO ACCOUNT FOR LINGERING LARGE AREA OF BKN-OVC CIGS
ACROSS WESTERN NORTH DAKOTA. AS MENTIONED BELOW...MODELS ARE
POORLY DEPICTING THESE CLOUDS...WHICH GREATLY AFFECT THIS MORNINGS
TEMPERATURES FORECAST. THE LATEST RAP APPEARS TO HINT AT THESE
CLOUDS...WHICH HOLD TOGETHER WELL INTO THIS MORNING. THUS
INCREASED SKY COVER WEST AND WARMED TEMPERATURES NEAR TO
UNDERNEATH THE CLOUDS. STILL COLD WHERE SKIES HAVE GONE
CLEAR...AROUND 25 BELOW AND PERHAPS COLDER WITH DEWPOINTS NEARING
30 BELOW.
&&
.SHORT TERM...(THIS MORNING THROUGH TONIGHT)
ISSUED AT 411 AM CST SUN DEC 29 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE VERY COLD
TEMPERATURES THIS MORNING AND AFTERNOON...FOLLOWED BY A SHOT OF
LIGHT ACCUMULATING SNOW FOR TONIGHT.
CURRENTLY...ARCTIC HIGH PRESSURE CONTINUES SOUTH INTO NORTH
DAKOTA EARLY THIS MORNING...RESULTING IN A RAPIDLY CLEARING SKY
ACROSS MY NORTH CENTRAL SPREADING SOUTHWARD. MODELS FAILED TO PICK
UP ON A RATHER LARGE AREA OF 4-5K FOOT AGL CIGS FROM FAR SOUTH
CENTRAL SASKATCHEWAN EXTENDING SOUTHEAST INTO NORTHWESTERN NORTH
DAKOTA. IT IS UNCLEAR IF THESE CLOUDS WILL CLEAR OUT AT ALL WITH
RETURN FLOW DEVELOPING AFTER 12Z THIS MORNING AND INCREASING
CLOUDS EXPECTED FROM THE WEST. BUFFER SOUNDINGS DO SHOW A GRADUAL
SCATTERING OUT AFTER SUNRISE AS THE TOP OF THE CLOUD LAYER
DE-SATURATES DOWNWARD...SO DID TREND SKY COVER FOR THIS AREA TO
SCATTERED/MOSTLY SUNNY 12-15Z THIS MORNING.
AS THE SKY CLEARS AND WINDS CONTINUE TO SUBSIDE UNDERNEATH THE
ARCTIC HIGH...TEMPERATURES WILL RAPIDLY PLUMMET. ALREADY NEAR 15
BELOW OVER MY FAR NORTH CENTRAL...AND EXPECT LOWS OF 20 BELOW TO
NEAR 25 BELOW ZERO ACROSS PORTIONS OF CENTRAL NORTH DAKOTA THROUGH
8-9AM SUNDAY. WARMER SOUTHWEST AROUND 5 BELOW WHERE LINGERING
CLOUDS ARE FORECAST. WIND CHILL HEADLINES LOOK FINE AND WILL MAKE
NO CHANGES WITH THIS FORECAST ISSUANCE.
COLD START OF THE DAY WILL RESULT IN SUBZERO HIGHS OVER MY CENTRAL
(NEAR -5F) AND MY EAST (NEAR -10F). BETTER SOUTHERLY RETURN FLOW
AND WAA ACROSS MY SOUTHWEST WHERE WE HAVE FORECAST HIGHS AROUND
10F ABOVE ZERO.
ACTIVE WEATHER PATTERN CONTINUES AS ANOTHER CLIPPER TRACKS
SOUTHEAST ACROSS THE NORTHERN PLAINS TONIGHT. UPPER LEVEL 125KT
JET STREAK NOW RIDING OVER THE UPPER LEVEL RIDGE PARKED OFF THE
WEST COAST WILL MOVE SOUTHEAST TONIGHT TO OVER THE NORTHERN HIGH
PLAINS OF MT/WY. THIS FEATURE WILL DRIVE A MID LEVEL IMPULSE AND
ASSOCIATED SURFACE LOW FROM EASTERN MONTANA THIS EVENING
SOUTHEAST INTO CENTRAL SOUTH DAKOTA AFTER MIDNIGHT. THE TRACK OF
THIS LOW AND PLACEMENT OF UPPER LEVEL DIVERGENCE WILL FAVOR
PRECIPITATION DEVELOPING ACROSS THE NORTHWEST THIS EVENING...THEN
SPREADING EAST-SOUTHEAST LATE SUNDAY NIGHT ACROSS CENTRAL ND AND
EVENTUALLY INTO THE JAMES RIVER BASIN AND SOUTHERN RED RIVER
VALLEY MONDAY MORNING. THANKS TO SNOW RATIOS RANGING FROM 15:1 TO
20:1...MAY SEE IN INCH TO AN INCH AND ONE HALF OF SNOW BY MONDAY
MORNING ALONG THE ABOVE MENTIONED TRACK...ROUGHLY ACROSS THE
NORTHWEST QUARTER OF THE STATE SOUTHEAST THROUGH MINOT AND
BISMARCK AND THROUGH THE JAMES RIVER BASIN.
WHILE WINDS WILL TRANSITION TO NORTH/NORTHWEST BEHIND THIS
CLIPPER AND INCREASE SOME...GRADIENT FORCING AND PRESSURE RISES
RATHER WEAK SO AM NOT ANTICIPATING MUCH BLOWING SNOW POTENTIAL AT
THIS TIME.
ONE MORE THING OF NOTE...EXPECT TEMPERATURES TO WARM THIS EVENING
ESPECIALLY SOUTHWEST INTO SOUTH CENTRAL WHERE THE BEST WAA WILL
OCCUR TONIGHT AHEAD OF THE LOW BEFORE CAA OVERTAKES US FOR MONDAY
DAYTIME. THUS EXPECT TO SEE TODAYS HIGH TEMPERATURES REACHED MANY
LOCATIONS SOMETIME THIS SUNDAY EVENING...AND MONDAYS HIGHS MOST
LIKELY SOMETIME AFTER MIDNIGHT THROUGH MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 411 AM CST SUN DEC 29 2013
MODELS CONTINUE THE TREND OF A COLD UPPER LOW OVER CENTRAL CANADA
REMAINING QUASI STATIONARY...ALBEIT MEANDERING A BIT...DURING THE
EXTENDED FORECAST PERIOD. AT THE SAME TIME...EASTERN PACIFIC RIDGING
REMAINS IN PLACE FEEDING MILDER TEMPERATURES TO THE WESTERN US.
ACROSS THE NORTHERN PLAINS...THE BATTLE BETWEEN THE WARM AND COLD
WILL BRING AN ACTIVE WEATHER PATTERN TO THE REGION. TUESDAY AND
WEDNESDAY MORNINGS SHOULD REMAIN QUITE COLD...WITH LOWS AS COLD AS
THE MID 20S BELOW ACROSS THE NORTH CENTRAL. COLD WIND CHILLS WILL
AGAIN BE FEATURED AT THIS TIME ESPECIALLY ALONG THE CANADIAN BORDER.
THEN A SHORTWAVE WILL MOVE ACROSS THE NORTHERN PLAINS AND BRING A
CHANCE OF SNOW THROUGH THE FIRST HALF OF THE PERIOD. ACCUMULATING
SNOW APPEARS LIKELY TUESDAY AND WEDNESDAY. AFTER WEDNESDAY...THE
ARCTIC AIR GETS NUDGED BACK NORTH AND MODERATING TEMPERATURES...
ESPECIALLY BY FRIDAY AND SATURDAY MAKE THERE WAY BACK TO NORTH
DAKOTA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 550 AM CST SUN DEC 29 2013
BKN-OVC MID LEVEL CLOUDS WILL SLOWLY CLEAR NOW THROUGH 15Z CENTRAL
AND EAST AS SURFACE HIGH PRESSURE BUILDS ACROSS NORTH DAKOTA.
LINGERING BKN-OVC CIGS AROUND 5K FT AGL MAY LINGER THROUGH THE
MORNING ACROSS THE WEST...IMPACTING KISN-KDIK. OVERALL...VFR
FLIGHT CONDITIONS EXPECTED THROUGH SUNDAY AFTERNOON. ANOTHER
CLIPPER STORM SYSTEM WILL MOVE SOUTHEAST INTO THE DAKOTAS SUNDAY
EVENING OVERNIGHT INTO MONDAY MORNING. EXPECT TO SEE DETERIORATING
FLIGHT CONDITIONS WEST SUNDAY EVENING IMPACTING KISN AND
KDIK...THEN EASTWARD LATER SUNDAY NIGHT IMPACTING KBIS-KMOT- KJMS.
CIGS ARE FORECAST TO DROP TO MVFR AND VIS IN FALLING SNOW FALLING
TO IFR AND POSSIBLY LOWER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 1 PM CST /NOON MST/ THIS AFTERNOON FOR
NDZ001-009-010-017>021-031>035-040>046.
WIND CHILL WARNING UNTIL 1 PM CST THIS AFTERNOON FOR NDZ002>005-
011>013-022-023-025-036-037-047-048-050-051.
&&
$$
UPDATE...NH
SHORT TERM...NH
LONG TERM...WAA
AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
142 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 142 AM CST SUN DEC 29 2013
MAIN UPDATES WITH THE EARLY MORNING FORECAST ISSUANCE WAS TO
ADJUST TEMPERATURES AND SKY COVER TRENDS.
1040 SURFACE HIGH WILL CONTINUE SOUTH INTO NORTH DAKOTA NOW
THROUGH 12Z...RESULTING IN CLEARING SKIES FROM NORTH TO SOUTH AND
DECREASING WINDS. AS THE SKIES CLEAR AND WIND
SUBSIDE...TEMPERATURES WILL RAPIDLY PLUMMET. EXPECT LOWS OF 20
BELOW TO NEAR 30 BELOW ZERO ACROSS PORTIONS OF CENTRAL NORTH
DAKOTA. WARMER SOUTHWEST AROUND 10 BELOW WHERE LINGERING CLOUDS
ARE FORECAST. TEMPERATURES WERE ADJUSTED BASED ON LATEST HR MODEL
DATA OF THE RAP AND HRRR.
NO CHANGES TO WIND CHILL HEADLINES.
UPDATE ISSUED AT 910 PM CST SAT DEC 28 2013
ALLOWED THE BLIZZARD WARNING TO EXPIRE OVER THE JAMES RIVER BASIN.
TEMPERATURES WILL CONTINUE TO PLUMMET AS AN ARCTIC AIR MASS BUILDS
INTO THE REGION.
OTHERWISE...THE LATEST RAP AND UPSTREAM OBS INDICATE SCATTERED
FLURRIES DEVELOPING OVER WESTERN NORTH DAKOTA AFTER MIDNIGHT.
AFTER COLLABORATING WITH THE MONTANA OFFICES AND RAPID
CITY...DECIDED TO ADD FLURRIES OVER WESTERN NORTH DAKOTA.
OTHERWISE...THE REMAINING FORECAST ELEMENTS ARE IN GOOD SHAPE. THE
UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 719 PM CST SAT DEC 28 2013
SENT OUT AN UPDATE TO ALLOW THE BLIZZARD WARNING TO EXPIRE ACROSS
THE NORTHEASTERN CWA THIS EVENING. HOWEVER...MAINTAINED THE
BLIZZARD WARNING FOR THE SOUTHERN JAMES RIVER BASIN FOR THE NEXT
FEW HOURS AS WINDS CONTINUE TO GUST UP TO 40 MPH GENERATING
BLOWING SNOW.
THE UPDATED PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 520 PM CST SAT DEC 28 2013
UPDATED THE FORECAST TO CANCEL THE BLIZZARD WARNING FOR AREAS
ALONG AND WEST OF HIGHWAY 83 ACROSS NORTHWESTERN NORTH DAKOTA.
WINDS CONTINUE TO COME DOWN AND VISIBILITIES CONTINUE TO IMPROVE.
HOWEVER...ACROSS THE EASTERN CWA...BLIZZARD CONDITIONS CONTINUE TO
BE REPORTED...ESPECIALLY ACROSS THE JAMES RIVER BASIN. WILL KEEP
THE BLIZZARD WARNING IN EFFECT THROUGH EARLY EVENING THERE AS A RESULT.
IN ADDITION...EXPANDED THE AREAL COVERAGE OF THE WIND CHILL
WARNING BASED ON LATEST OBS/TRENDS. THE UPDATED PRODUCTS HAVE BEEN
SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 311 PM CST SAT DEC 28 2013
MAIN CONCERNS ARE WINTER HEADLINES AND DANGEROUS WIND CHILLS AS
ARCTIC AIR CONTINUES TO OVERSPREAD THE STATE. LOW PRESSURE CENTER
HAS MOVED TO SOUTHERN MINNESOTA WITH STRONG NORTHWEST WINDS
CONTINUING ACROSS OUR REGION.
BLIZZARD WARNING REMAINS IN EFFECT FOR MUCH OF NORTHERN CWA INTO
THE JAMES RIVER VALLEY INTO THE EARLY EVENING. CONDITIONS ARE
BEGINNING TO IMPROVE ACROSS THE NORTHWEST AND EXPECTED TO
DETERIORATE SOUTHEAST INTO THIS EVENING AS BAND OF LIGHT SNOW
SPREADS ACROSS THAT AREA WITH VERY STRONG WINDS CONTINUING.
BLIZZARD WARNING ENDS AT 01Z EVERYWHERE EXCEPT FAR SOUTHEAST WHICH
CONTINUES UNTIL 3Z...WHEN CONDITIONS SHOULD IMPROVE.
WIND CHILLS AT 21Z RANGED FROM 20 TO 30 BELOW ZERO ACROSS THE NORTH
AND THE NEGATIVE TEENS SOUTH. ENTIRE AREA IS COVERED BY WIND CHILL
ADVISORY WITH A WIND CHILL WARNING REMAINING IN PLACE ACROSS THE
NORTHEAST WITH WIND CHILLS TO 45 BELOW EXPECTED TONIGHT. MODELS IN
GOOD AGREEMENT WITH HIGH PRESSURE BUILDING IN ACROSS THE STATE
OVERNIGHT ALONG WITH DIMINISHING WINDS AND CLEARING SKIES. RETURN
FLOW SETS UP BY SUNDAY AFTERNOON ACROSS THE WEST AS HIGH PRESSURE
CONTINUES TO SLIDES OVER EASTERN SOUTH DAKOTA WITH INCREASING
CLOUDS AND SOME MODERATION IN TEMPERATURES REACHING SINGLE DIGITS
ABOVE ZERO WEST AND BELOW ZERO ELSEWHERE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 311 PM CST SAT DEC 28 2013
THE HIGHLIGHTS OF THE EXTENDED FORECAST ARE DANGEROUS WIND CHILLS
FOR MUCH OF THE AREA SUNDAY THROUGH TUESDAY NIGHTS...AND
ACCUMULATING SNOW TUESDAY.
THE 12 UTC CONSENSUS IS IN AGREEMENT ON THE THE BOUNDARY OF THE
ARCTIC AIRMASS TO REMAIN ACROSS EASTERN MONTANA INTO SOUTHWEST
NORTH DAKOTA SUNDAY NIGHT THROUGH WEDNESDAY. THUS...DANGEROUS
NIGHTTIME AND EARLY MORNING WIND CHILLS SHOULD CONTINUE ACROSS
MUCH OF NORTHERN AND CENTRAL NORTH DAKOTA SUNDAY THROUGH WEDNESDAY
NIGHTS...WITH THE RELATIVELY WARMER SOUTHWEST FORECAST AT THIS
TIME TO REMAIN ABOVE ADVISORY CRITERIA.
IN REGARDS TO PRECIPITATION...A WAVE COMING ONSHORE TO BRITISH
COLUMBIA MONDAY IS FORECAST TO PROPAGATE SOUTHEAST AND INTERACT
WITH THE LOW LEVEL BAROCLINIC ZONE ON TUESDAY. AS A RESULT...A
BAND OF LIGHT TO MODERATE ACCUMULATING SNOW MAY BE POSSIBLE ACROSS
THE WEST AND FAR SOUTH CENTRAL. ADVISORY LEVEL SNOWFALL
ACCUMULATIONS MAY BE POSSIBLE...HOWEVER...WINDS ARE EXPECTED TO BE
LIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 142 AM CST SUN DEC 29 2013
BKN-OVC MID LEVEL CLOUDS WILL SLOWLY CLEAR NOW THROUGH 12-15Z AS
SURFACE HIGH PRESSURE BUILDS ACROSS NORTH DAKOTA. VFR FLIGHT
CONDITIONS EXPECTED THROUGH SUNDAY AFTERNOON. ANOTHER CLIPPER
STORM SYSTEM WILL MOVE SOUTHEAST INTO THE DAKOTAS SUNDAY EVENING
OVERNIGHT INTO MONDAY MORNING. EXPECT TO SEE DETERIORATING FLIGHT
CONDITIONS WEST SUNDAY EVENING IMPACTING KISN AND KDIK...THEN
EASTWARD LATER SUNDAY NIGHT IMPACTING KBIS-KMOT-KJMS. CIGS ARE
FORECAST TO DROP TO MVFR AND VIS IN FALLING SNOW FALLING TO IFR
AND POSSIBLY LOWER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 1 PM CST /NOON MST/ THIS AFTERNOON FOR
NDZ001-009-010-017>021-031>035-040>046.
WIND CHILL WARNING UNTIL 1 PM CST THIS AFTERNOON FOR NDZ002>005-
011>013-022-023-025-036-037-047-048-050-051.
&&
$$
UPDATE...NH
SHORT TERM...JNS
LONG TERM...AYD
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
747 AM EST SUN DEC 29 2013
.SYNOPSIS...
LOW PRESSURE MOVES UP THE EAST COAST TODAY. COLD FRONT LATE SUNDAY
NIGHT INTO MONDAY. HIGH PRESSURE TUESDAY. ANOTHER SYSTEM THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
FORECAST FOR MUCH OF TODAY IS GENERALLY ON TRACK. HOWEVER...
APPEARS CURRENT FORECAST HAS TEMPS FALLING MUCH FASTER THAN
CURRENT THINKING. HAVE NOT MADE WHOLESALE CHANGES...BUT HAVE MADE
SOME TWEAKS TO TEMPS AND CORRESPONDING WEATHER GRIDS TO REFLECT
CURRENT THINKING.
PREVIOUS DISCUSSION...
EXTENSIVE SHIELD OF RAIN HAS NOW OVERSPREAD THE AREA...AND SHOULD
CONTINUE TO ENCOMPASS MOST COUNTIES THROUGH 12Z TODAY. SURFACE LOW
PRESSURE BRINGING THE MOISTURE INTO THE CWA WILL RACE UP THE EAST
COAST. WILL START LOSING THE DEPTH OF THIS MOISTURE AFTER 18Z
TODAY...AND WILL REDUCE THE POPS ACCORDINGLY AS THE UPPER AND MID
LEVELS ACQUIRE DRIER AIR. STILL EXPECTING TOTALS TO TOP OUT IN THE
1 TO 1.25 INCH RANGE...LIKELY OVER SOUTHWEST VIRGINIA AND THE
SOUTHERN MOUNTAINS.
TIMING IS STILL IN GOOD AGREEMENT AMONGST THE MODELS...BUT HAVE
FOCUSED ON THE HIGH RESOLUTION HRRR AND WRF MODELS FOR THE TIMING IN
TERMS OF DECREASING THE POPS THROUGH THE AFTERNOON AND EVENING.
MEANWHILE...A COLD FRONT CURRENTLY PLOWING THROUGH THE NORTHERN
PLAINS USHERING A BITTERLY COLD ARCTIC AIRMASS. THIS COLD FRONT WILL
RAPIDLY PUSH THROUGH THE SOUTHERN GREAT LAKES...AND WILL REACH OUR
SOUTHEAST OHIO COUNTIES AFTER 00Z MONDAY. IT WILL NOT BE BRINGING
QUITE THE SAME AIR CURRENTLY FILLING IN BEHIND THE FRONT IN
MINNESOTA AND THE DAKOTAS...BUT IT WILL BE A SIGNIFICANT AIRMASS
CHANGE FOR THE MIDDLE OHIO VALLEY. CAN EXPECT A FEW SNOW SHOWERS
WITH THE FRONT...AND THEN NORTHWESTERLY FLOW IN PLUNGING 850MB
TEMPERATURE AIR BRINGING UPSLOPING SNOW CONDITIONS THAT WILL EXTEND
INTO THE SHORT TERM FORECAST PERIOD.
NOT EXPECTING MUCH IN TERMS OF TEMPERATURE RECOVERY TODAY IN THE
RAIN...WITH UPPER 30S TO LOWER 40S EXPECTED. BEHIND THE COLD
FRONT...LOW 20S WILL FIND THEIR WAY INTO THE SOUTHEAST OHIO COUNTIES
BY 12Z MONDAY.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
THIS PERIOD WILL BE CHARACTERIZED BY FAST WEST TO NORTHWEST FLOW
ALOFT...WITH A DIGGING NORTHERN STREAM UPPER TROUGH OVER THE
MISSISSIPPI AND OHIO VALLEYS BY THURSDAY. OPERATIONAL MODELS ARE
STRONGLY TRENDING TOWARD THIS SCENARIO. IN THIS FAST FLOW...POST
COLD FRONTAL SNOW SHOWERS...MAINLY IN THE NORTHERN AND CENTRAL
MOUNTAINS...MOVE OUT QUICKLY MONDAY AFTERNOON...AS HIGH PRESSURE
BUILDS IN RAPIDLY FROM THE WEST AND ENDS THE COLD ADVECTION. WITH
NOT MUCH OF AN UPSLOPE EVENT AND MOISTURE RATHER SHALLOW...EXPECT
ONLY AN INCH OR TWO IN THE HIGHER ELEVATIONS BEFORE ENDING MONDAY
AFTERNOON. TEMPERATURES WILL BE BELOW NORMAL WITH MONDAY HIGHS
STRUGGLING TO REACH ABOVE FREEZING...EVEN WITH INCREASING SUNSHINE.
TUESDAY AND WEDNESDAY WILL SEE CLIPPER LIKE SYSTEMS TRACKING JUST TO
OUR NORTH...WITH THE MAIN EFFECT BEING SOME CLOUDS ACROSS THE NORTH
HALF OF THE AREA. PRECIP...HOWEVER...SHOULD ALSO STAY JUST NORTH
WHERE ALONG THE CLIPPER TRACK. TEMPERATURES WILL BE ON A SLOW RISE
TUESDAY AND WEDNESDAY WITH A WEAK SOUTHERLY FLOW...WITH HIGHS
REACHING TO NEAR NORMAL READINGS BY WEDNESDAY.
THE NEXT SIGNIFICANT LOW PRESSURE SYSTEM AND COLD FRONT FOR THURSDAY
WILL BE A REFLECTION OF THE DIGGING UPPER TROUGH. FORECAST
AMPLIFICATION OF THE UPPER TROUGH SUGGESTS THE TRACK OF THE SURFACE
LOW WILL BE CLOSE TO OUR AREA. THIS WILL PUT US ON THE EDGE OF
WINTRY VERSUS LIQUID PRECIP. FOR NOW...WILL KEEP A WINTRY MIX
THURSDAY AND THEN SNOW SHOWERS THURSDAY NIGHT BEHIND THE COLD FRONT.
BUT WOULD NOT BE SURPRISED TO SEE A NORTHWARD SHIFT OF THE SURFACE
LOW AND WARMER SCENARIO AHEAD OF THE COLD FRONT ON FUTURE MODEL
RUNS.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
LOW PRESSURE AND SNOW SHOWERS MOVE OUT FRIDAY. SNOW ACCUMULATIONS
ARE ANTICIPATED...ESPECIALLY OVER THE NORTHEAST MOUNTAINS BY EARLY
FRIDAY.
WPC CONTINUES HONORING THE ECMWF SOLUTION IN THE EXTENDED FORECAST.
BLENDED WPC AND GMOS FOR WINDS AND TEMPERATURES THROUGH THE PERIOD
DUE TO LOWER CONFIDENCE BEYOND DAY 4. TEMPERATURES WILL DEPEND ON
THE TRAJECTORIES OF THE AFOREMENTIONED SHORTWAVES AS THEY WILL
REINFORCE THE COLD AIR BEHIND ANY SFC REFLECTION...AND BRING PLENTY
OF CLOUDINESS.
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
WITH SOLID RAIN COVERAGE ON RADAR...ONLY A MATTER OF TIME BEFORE
TERMINALS COME DOWN TO IFR CONDITIONS. AFTER 12Z...CEILINGS COULD
COME DOWN TO THE 0.3 TO 0.5KFT RANGE FOR 2 TO 4 HOURS. HAVE ADDED
TEMPO GROUPS TO THESE TERMINALS FOR IFR CEILINGS DURING THE
PREVAILING LIFR.
RAIN MOVES OUT AFTER 18Z TODAY AND THE WINDS WILL INCREASE. A COLD
FRONT APPROACHES AND WILL CROSS THE OHIO RIVER AFTER 03Z MONDAY.
SOME BRIEF SNOW ACCOMPANIES THE COLD FRONT CAUSING IFR
RESTRICTIONS THAT WILL BE FIT FOR TEMPO GROUPS IN FUTURE
ISSUANCES. LATE MONDAY NIGHT WILL SEE THE BEGINNING OF UPSLOPE
SNOW SHOWERS BEHIND THE FRONT...AFFECTING ALL TERMINALS EXCEPT PKB
AND HTS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: LIFR CONDITIONS MAY NOT MATERIALIZE.
OBSERVATIONS LIKELY TO BOUNCE IN THE RAIN BETWEEN LIFR AND MVFR.
AMENDMENTS LIKELY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY M M M H H H H H H H H H
HTS CONSISTENCY H M M H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY M M M M H M H H H M L L
PKB CONSISTENCY M L L H H H H H H H H H
CKB CONSISTENCY H H M M M H H H H H H H
AFTER 12Z MONDAY...
IFR POSSIBLE IN UPSLOPE SNOW SHOWERS AFTER 12Z MONDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...JSH/26
SHORT TERM...JMV
LONG TERM...ARJ
AVIATION...26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
543 AM EST SUN DEC 29 2013
.SYNOPSIS...
LOW PRESSURE MOVES UP THE EAST COAST TODAY. COLD FRONT LATE SUNDAY
NIGHT INTO MONDAY. HIGH PRESSURE TUESDAY. ANOTHER SYSTEM THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
NO CHANGES TO THE FORECAST THIS MORNING AS RAIN CONTINUES TO FALL
WITH A FEW BREAKS IN THE PRECIPITATION SHIELD HERE AND THERE.
PREVIOUS DISCUSSION...
EXTENSIVE SHIELD OF RAIN HAS NOW OVERSPREAD THE AREA...AND SHOULD
CONTINUE TO ENCOMPASS MOST COUNTIES THROUGH 12Z TODAY. SURFACE LOW
PRESSURE BRINGING THE MOISTURE INTO THE CWA WILL RACE UP THE EAST
COAST. WILL START LOSING THE DEPTH OF THIS MOISTURE AFTER 18Z
TODAY...AND WILL REDUCE THE POPS ACCORDINGLY AS THE UPPER AND MID
LEVELS ACQUIRE DRIER AIR. STILL EXPECTING TOTALS TO TOP OUT IN THE 1
TO 1.25 INCH RANGE...LIKELY OVER SOUTHWEST VIRGINIA AND THE SOUTHERN
MOUNTAINS.
TIMING IS STILL IN GOOD AGREEMENT AMONGST THE MODELS...BUT HAVE
FOCUSED ON THE HIGH RESOLUTION HRRR AND WRF MODELS FOR THE TIMING IN
TERMS OF DECREASING THE POPS THROUGH THE AFTERNOON AND EVENING.
MEANWHILE...A COLD FRONT CURRENTLY PLOWING THROUGH THE NORTHERN
PLAINS USHERING A BITTERLY COLD ARCTIC AIRMASS. THIS COLD FRONT WILL
RAPIDLY PUSH THROUGH THE SOUTHERN GREAT LAKES...AND WILL REACH OUR
SOUTHEAST OHIO COUNTIES AFTER 00Z MONDAY. IT WILL NOT BE BRINGING
QUITE THE SAME AIR CURRENTLY FILLING IN BEHIND THE FRONT IN
MINNESOTA AND THE DAKOTAS...BUT IT WILL BE A SIGNIFICANT AIRMASS
CHANGE FOR THE MIDDLE OHIO VALLEY. CAN EXPECT A FEW SNOW SHOWERS
WITH THE FRONT...AND THEN NORTHWESTERLY FLOW IN PLUNGING 850MB
TEMPERATURE AIR BRINGING UPSLOPING SNOW CONDITIONS THAT WILL EXTEND
INTO THE SHORT TERM FORECAST PERIOD.
NOT EXPECTING MUCH IN TERMS OF TEMPERATURE RECOVERY TODAY IN THE
RAIN...WITH UPPER 30S TO LOWER 40S EXPECTED. BEHIND THE COLD
FRONT...LOW 20S WILL FIND THEIR WAY INTO THE SOUTHEAST OHIO COUNTIES
BY 12Z MONDAY.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
THIS PERIOD WILL BE CHARACTERIZED BY FAST WEST TO NORTHWEST FLOW
ALOFT...WITH A DIGGING NORTHERN STREAM UPPER TROUGH OVER THE
MISSISSIPPI AND OHIO VALLEYS BY THURSDAY. OPERATIONAL MODELS ARE
STRONGLY TRENDING TOWARD THIS SCENARIO. IN THIS FAST FLOW...POST
COLD FRONTAL SNOW SHOWERS...MAINLY IN THE NORTHERN AND CENTRAL
MOUNTAINS...MOVE OUT QUICKLY MONDAY AFTERNOON...AS HIGH PRESSURE
BUILDS IN RAPIDLY FROM THE WEST AND ENDS THE COLD ADVECTION. WITH
NOT MUCH OF AN UPSLOPE EVENT AND MOISTURE RATHER SHALLOW...EXPECT
ONLY AN INCH OR TWO IN THE HIGHER ELEVATIONS BEFORE ENDING MONDAY
AFTERNOON. TEMPERATURES WILL BE BELOW NORMAL WITH MONDAY HIGHS
STRUGGLING TO REACH ABOVE FREEZING...EVEN WITH INCREASING SUNSHINE.
TUESDAY AND WEDNESDAY WILL SEE CLIPPER LIKE SYSTEMS TRACKING JUST TO
OUR NORTH...WITH THE MAIN EFFECT BEING SOME CLOUDS ACROSS THE NORTH
HALF OF THE AREA. PRECIP...HOWEVER...SHOULD ALSO STAY JUST NORTH
WHERE ALONG THE CLIPPER TRACK. TEMPERATURES WILL BE ON A SLOW RISE
TUESDAY AND WEDNESDAY WITH A WEAK SOUTHERLY FLOW...WITH HIGHS
REACHING TO NEAR NORMAL READINGS BY WEDNESDAY.
THE NEXT SIGNIFICANT LOW PRESSURE SYSTEM AND COLD FRONT FOR THURSDAY
WILL BE A REFLECTION OF THE DIGGING UPPER TROUGH. FORECAST
AMPLIFICATION OF THE UPPER TROUGH SUGGESTS THE TRACK OF THE SURFACE
LOW WILL BE CLOSE TO OUR AREA. THIS WILL PUT US ON THE EDGE OF
WINTRY VERSUS LIQUID PRECIP. FOR NOW...WILL KEEP A WINTRY MIX
THURSDAY AND THEN SNOW SHOWERS THURSDAY NIGHT BEHIND THE COLD FRONT.
BUT WOULD NOT BE SURPRISED TO SEE A NORTHWARD SHIFT OF THE SURFACE
LOW AND WARMER SCENARIO AHEAD OF THE COLD FRONT ON FUTURE MODEL
RUNS.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
LOW PRESSURE AND SNOW SHOWERS MOVE OUT FRIDAY. SNOW ACCUMULATIONS
ARE ANTICIPATED...ESPECIALLY OVER THE NORTHEAST MOUNTAINS BY EARLY
FRIDAY.
WPC CONTINUES HONORING THE ECMWF SOLUTION IN THE EXTENDED FORECAST.
BLENDED WPC AND GMOS FOR WINDS AND TEMPERATURES THROUGH THE PERIOD
DUE TO LOWER CONFIDENCE BEYOND DAY 4. TEMPERATURES WILL DEPEND ON
THE TRAJECTORIES OF THE AFOREMENTIONED SHORTWAVES AS THEY WILL
REINFORCE THE COLD AIR BEHIND ANY SFC REFLECTION...AND BRING PLENTY
OF CLOUDINESS.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
WITH SOLID RAIN COVERAGE ON RADAR...ONLY A MATTER OF TIME BEFORE
TERMINALS COME DOWN TO IFR CONDITIONS. AFTER 12Z...CEILINGS COULD
COME DOWN TO THE 0.3 TO 0.5KFT RANGE FOR 2 TO 4 HOURS. HAVE ADDED
TEMPO GROUPS TO THESE TERMINALS FOR IFR CEILINGS DURING THE
PREVAILING LIFR.
RAIN MOVES OUT AFTER 18Z TODAY AND THE WINDS WILL INCREASE. A COLD
FRONT APPROACHES AND WILL CROSS THE OHIO RIVER AFTER 03Z MONDAY.
SOME BRIEF SNOW ACCOMPANIES THE COLD FRONT CAUSING IFR
RESTRICTIONS THAT WILL BE FIT FOR TEMPO GROUPS IN FUTURE
ISSUANCES. LATE MONDAY NIGHT WILL SEE THE BEGINNING OF UPSLOPE
SNOW SHOWERS BEHIND THE FRONT...AFFECTING ALL TERMINALS EXCEPT PKB
AND HTS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: LIFR CONDITIONS MAY NOT MATERIALIZE.
OBSERVATIONS LIKELY TO BOUNCE IN THE RAIN BETWEEN LIFR AND MVFR.
AMENDMENTS LIKELY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY M M M H H H H H H H H H
HTS CONSISTENCY H M M H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY M M M M H M H H H M L L
PKB CONSISTENCY M L L H H H H H H H H H
CKB CONSISTENCY H H M M M H H H H H H H
AFTER 12Z MONDAY...
IFR POSSIBLE IN UPSLOPE SNOW SHOWERS AFTER 12Z MONDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...26
SHORT TERM...JMV
LONG TERM...ARJ
AVIATION...26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
336 AM EST SUN DEC 29 2013
.SYNOPSIS...
LOW PRESSURE MOVES UP THE EAST COAST TODAY. COLD FRONT LATE SUNDAY
NIGHT INTO MONDAY. HIGH PRESSURE TUESDAY. ANOTHER SYSTEM THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
EXTENSIVE SHIELD OF RAIN HAS NOW OVERSPREAD THE AREA...AND SHOULD
CONTINUE TO ENCOMPASS MOST COUNTIES THROUGH 12Z TODAY. SURFACE LOW
PRESSURE BRINGING THE MOISTURE INTO THE CWA WILL RACE UP THE EAST
COAST. WILL START LOSING THE DEPTH OF THIS MOISTURE AFTER 18Z
TODAY...AND WILL REDUCE THE POPS ACCORDINGLY AS THE UPPER AND MID
LEVELS ACQUIRE DRIER AIR. STILL EXPECTING TOTALS TO TOP OUT IN THE 1
TO 1.25 INCH RANGE...LIKELY OVER SOUTHWEST VIRGINIA AND THE SOUTHERN
MOUNTAINS.
TIMING IS STILL IN GOOD AGREEMENT AMONGST THE MODELS...BUT HAVE
FOCUSED ON THE HIGH RESOLUTION HRRR AND WRF MODELS FOR THE TIMING IN
TERMS OF DECREASING THE POPS THROUGH THE AFTERNOON AND EVENING.
MEANWHILE...A COLD FRONT CURRENTLY PLOWING THROUGH THE NORTHERN
PLAINS USHERING A BITTERLY COLD ARCTIC AIRMASS. THIS COLD FRONT WILL
RAPIDLY PUSH THROUGH THE SOUTHERN GREAT LAKES...AND WILL REACH OUR
SOUTHEAST OHIO COUNTIES AFTER 00Z MONDAY. IT WILL NOT BE BRINGING
QUITE THE SAME AIR CURRENTLY FILLING IN BEHIND THE FRONT IN
MINNESOTA AND THE DAKOTAS...BUT IT WILL BE A SIGNIFICANT AIRMASS
CHANGE FOR THE MIDDLE OHIO VALLEY. CAN EXPECT A FEW SNOW SHOWERS
WITH THE FRONT...AND THEN NORTHWESTERLY FLOW IN PLUNGING 850MB
TEMPERATURE AIR BRINGING UPSLOPING SNOW CONDITIONS THAT WILL EXTEND
INTO THE SHORT TERM FORECAST PERIOD.
NOT EXPECTING MUCH IN TERMS OF TEMPERATURE RECOVERY TODAY IN THE
RAIN...WITH UPPER 30S TO LOWER 40S EXPECTED. BEHIND THE COLD
FRONT...LOW 20S WILL FIND THEIR WAY INTO THE SOUTHEAST OHIO COUNTIES
BY 12Z MONDAY.
&&
.SHORT TERM /MONDAY THROUGH THURSDAY NIGHT/...
THIS PERIOD WILL BE CHARACTERIZED BY FAST WEST TO NORTHWEST FLOW
ALOFT...WITH A DIGGING NORTHERN STREAM UPPER TROUGH OVER THE
MISSISSIPPI AND OHIO VALLEYS BY THURSDAY. OPERATIONAL MODELS ARE
STRONGLY TRENDING TOWARD THIS SCENARIO. IN THIS FAST FLOW...POST
COLD FRONTAL SNOW SHOWERS...MAINLY IN THE NORTHERN AND CENTRAL
MOUNTAINS...MOVE OUT QUICKLY MONDAY AFTERNOON...AS HIGH PRESSURE
BUILDS IN RAPIDLY FROM THE WEST AND ENDS THE COLD ADVECTION. WITH
NOT MUCH OF AN UPSLOPE EVENT AND MOISTURE RATHER SHALLOW...EXPECT
ONLY AN INCH OR TWO IN THE HIGHER ELEVATIONS BEFORE ENDING MONDAY
AFTERNOON. TEMPERATURES WILL BE BELOW NORMAL WITH MONDAY HIGHS
STRUGGLING TO REACH ABOVE FREEZING...EVEN WITH INCREASING SUNSHINE.
TUESDAY AND WEDNESDAY WILL SEE CLIPPER LIKE SYSTEMS TRACKING JUST TO
OUR NORTH...WITH THE MAIN EFFECT BEING SOME CLOUDS ACROSS THE NORTH
HALF OF THE AREA. PRECIP...HOWEVER...SHOULD ALSO STAY JUST NORTH
WHERE ALONG THE CLIPPER TRACK. TEMPERATURES WILL BE ON A SLOW RISE
TUESDAY AND WEDNESDAY WITH A WEAK SOUTHERLY FLOW...WITH HIGHS
REACHING TO NEAR NORMAL READINGS BY WEDNESDAY.
THE NEXT SIGNIFICANT LOW PRESSURE SYSTEM AND COLD FRONT FOR THURSDAY
WILL BE A REFLECTION OF THE DIGGING UPPER TROUGH. FORECAST
AMPLIFICATION OF THE UPPER TROUGH SUGGESTS THE TRACK OF THE SURFACE
LOW WILL BE CLOSE TO OUR AREA. THIS WILL PUT US ON THE EDGE OF
WINTRY VERSUS LIQUID PRECIP. FOR NOW...WILL KEEP A WINTRY MIX
THURSDAY AND THEN SNOW SHOWERS THURSDAY NIGHT BEHIND THE COLD FRONT.
BUT WOULD NOT BE SURPRISED TO SEE A NORTHWARD SHIFT OF THE SURFACE
LOW AND WARMER SCENARIO AHEAD OF THE COLD FRONT ON FUTURE MODEL
RUNS.
&&
.LONG TERM /FRIDAY THROUGH SATURDAY/...
LOW PRESSURE AND SNOW SHOWERS MOVE OUT FRIDAY. SNOW ACCUMULATIONS
ARE ANTICIPATED...ESPECIALLY OVER THE NORTHEAST MOUNTAINS BY EARLY
FRIDAY.
WPC CONTINUES HONORING THE ECMWF SOLUTION IN THE EXTENDED FORECAST.
BLENDED WPC AND GMOS FOR WINDS AND TEMPERATURES THROUGH THE PERIOD
DUE TO LOWER CONFIDENCE BEYOND DAY 4. TEMPERATURES WILL DEPEND ON
THE TRAJECTORIES OF THE AFOREMENTIONED SHORTWAVES AS THEY WILL
REINFORCE THE COLD AIR BEHIND ANY SFC REFLECTION...AND BRING PLENTY
OF CLOUDINESS.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
EXPECT CONDITIONS AT ALL TERMINALS TO GO DOWNHILL OVER THE NEXT
FEW HOURS AS THE RAIN SETTLES IN. EXPECT IFR OR POSSIBLY
WORSE...TO LIFR BY MORNING FOR MOST LOCATIONS AS THE LOW PRESSURE
SYSTEM MOVES UP THE ATLANTIC COAST. ANY BREAKS IN THE RAIN THROUGH
15Z SUNDAY WILL POSSIBLY RESULT IN THE LIFR CONDITIONS.
AS THE SYSTEM LIFTS TO THE NORTHEAST...MID AND UPPER LEVEL
MOISTURE WILL GRADUALLY EXIT...TAKING THE RAIN WITH IT BY 00Z
MONDAY. CEILINGS WILL IMPROVE TO MVFR AS WILL
VISIBILITIES...POSSIBLY REACHING VFR...AS WEST WINDS INCREASE TO
10KTS...STIRRING UP THE LOWEST LEVELS OF THE ATMOSPHERE.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TEMPOS FOR OSCILLATIONS BETWEEN IFR AND LIFR
MAY BE NEEDED THROUGH 15Z. AMENDMENTS POSSIBLE FOR THIS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SUN 12/29/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EST 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
CRW CONSISTENCY H H H M H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY M L L H H M M M H M M H
EKN CONSISTENCY M M L L L L M H H H H H
PKB CONSISTENCY H H M H M L H H H H H H
CKB CONSISTENCY H H H H M M M M H H H H
AFTER 06Z MONDAY...
IFR POSSIBLE IN SNOW SHOWERS AFTER 06Z MONDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...26
SHORT TERM...JMV
LONG TERM...JMV/ARJ
AVIATION...26
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1247 AM EST SUN DEC 29 2013
.SYNOPSIS...
RAIN WILL OCCUR WELL NORTH AND WEST OF A LOW PRESSURE SYSTEM THAT
WILL TRACK FROM THE GULF COAST INTO THE MID ATLANTIC TONIGHT INTO
TOMORROW. A COLD FRONT MOVING IN FROM THE NORTHWEST WILL QUICKLY
FOLLOW LATE SUNDAY INTO SUNDAY EVENING. HIGH PRESSURE WILL BUILD
IN MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SHIELD OF RAIN CONTINUES TO ADVANCE NORTH NORTHEAST ACROSS
KENTUCKY. THE WESTERN EDGE OF THIS LOOKS RAGGED BUT SOME LIGHT
PRECIPITATION IS STILL LIKELY REACHING THE GROUND THERE. LATEST
HRRR AND RAP RUNS HAVE COME INTO PRETTY GOOD AGREEMENT IN
SPREADING THE RAIN ACROSS MOST OF THE FORECAST AREA LATE TONIGHT
INTO SUNDAY MORNING. PROBABLY WILL NOT BE A STEADY RAIN
PARTICULARLY IN THE WESTERN AND NORTHERN AREAS BUT CHANCE OF
MEASURABLE PRECIPITATION CERTAINLY LOOKS HIGHER. THUS POPS HAVE
BEEN NUDGED UPWARD AGAIN.
TEMPERATURES WERE ADJUSTED TO ACCOUNT FOR RECENT OBSERVATIONAL
TRENDS WITH OUTLYING AREAS DROPPING A BIT FASTER THIS EVENING
DESPITE EXTENSIVE HIGH CLOUDS. EXPECT ONCE RAIN AND INCREASED LOW
LEVEL MOISTURE ARRIVE LATER TONIGHT THAT READINGS WILL LEVEL OUT
AND PERHAPS INCREASE A DEGREE OR TWO IN SOME PLACES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
CUT DOWN ON THE HIGH TEMPERATURES SUNDAY WHERE RAIN WOULD BE
STARTING THE DAY BUT THIS WAS ONLY ABOUT 2 DEGREES. NORTHERN AND
NORTHWEST TEMPS WERE LOOKING GOOD IN THE LOWER 40S.
RAIN WILL EXIT DURING THE MORNING AND A LULL IN PRECIPITATION IS
CALLED FOR IN THE EARLY AFTERNOON. UPPER LEVEL SHORTWAVE IS
HELPING SHUNT THE WESTERN EDGE OF THE PRECIPITATION ALONG QUICKLY
IN THE EARLY AFTERNOON. WHILE NOT A TYPICAL FIELD USED FOR
TIMING...THE H7 OMEGA IS SHOWING A PRONOUNCED MINIMA AT 15 AND 18Z
WHICH SHOULD INDICATE THE BACK EDGE OF THE RAINFALL.
ONCE COLDER AIR IS USHERED IN LATER IN THE DAY...LOOK FOR THE WIND
SHIFT TO NORTHWEST...ANY LINGERING MOISTURE WILL BE WRUNG OUT BY
THE FALLING TEMPERATURES THROUGH THE ATMOSPHERE AND A QUICK
TRANSITION TO SCATTERED SNOW SHOWERS APPEARS TO BE IN THE OFFING.
ANY OF THESE SNOW SHOWERS SHOULD BE LIGHT AND NOT A PROBLEM IN AND
OF THEMSELVES...LINGERING THROUGH ABOUT MIDNIGHT AND THEN TURNING
OFF AS THE AIRMASS DRIES SIGNIFICANTLY.
HIGH PRESSURE WILL BUILD OVER THE MIDWEST SUNDAY NIGHT AND MONDAY
AND CONTINUE TO FILTER IN COLDER AND DRIER AIR FOR ANOTHER TASTE
OF WINTER TO THE OHIO VALLEY FOR THE EARLY PART OF THE WEEK.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
EXTENDED MODELS HAVE CONVERGED WITH THEIR SOLUTIONS...BUT THERE
REMAINS SOME DIFFERENCES WITH THE DETAILS.
PERIOD BEGINS WITH A SYSTEM PASSING NORTH OF THE REGION THROUGH THE
GREAT LAKES. IT LOOKS LIKE THE PCPN SHOULD STAY TO THE N...WITH ONLY
SOME CLOUDS. MODELS THEN DROP SOME H5 ENERGY INTO THE ERN U.S. TROF
TUESDAY NIGHT. AN AREA OF ISENTROPIC LIFT ASSOCIATED WITH A WEAK
LOW/SFC TROF SWINGS ACROSS THE REGION TUESDAY NIGHT INTO WEDNESDAY.
THIS LIFT CAUSES AN AREA OF SNOW..MAINLY ACROSS THE NRN HALF OF THE
FA.
ON THURSDAY...THE MODELS PHASE SOME SRN AND NRN STREAM ENERGY ACROSS
THE ERN U.S. WHILE THE GFS/ECMWF AND CMC HEMISPHERIC ALL HAVE A
SYSTEM THAT AFFECTS THE AREA ON THURSDAY...THE STRENGTH OF THE
SYSTEM VARIES. WENT WITH A 12Z GFS/00Z ECMWF BLEND. THIS SPREADS
SNOW ACROSS MOST OF THE REGION WITH SOME RAIN/SNOW IN THE SE. HIGH
PRESSURE BUILDS IN FOR FRIDAY INTO SATURDAY.
WARMED UP HIGHS ON TUESDAY TO THE UPPER 20S IN WEST CENTRAL OHIO TO
THE MID 30S IN NRN KY. WITH THE WEAK CLIPPER TYPE SYSTEM ON
WEDNESDAY HIGHS WILL BE HELD DOWN INTO THE MID 20S TO LOWER 30S.
HIGHS WILL REMAIN ABOUT THE SAME THURSDAY INTO FRIDAY BEFORE WARMING
A FEW DEGREES SATURDAY. LOWS WILL TYPICALLY BE IN THE TEENS TO LOW
20S.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
RAIN WILL SPREAD NORTHWARD ACROSS THE AREA TONIGHT ASSOCIATED WITH
LOW PRESSURE LIFTING NORTHEAST ACROSS THE CAROLINAS. THIS
PRECIPITATION WILL BRING WITH IT OCCASIONAL MVFR VSBYS OVERNIGHT
AND INTO THE EARLY PARTS OF THE DAY SUNDAY. AS THE PRECIPITATION
SPREADS ACROSS THE AREA...OVERNIGHT LOW LEVEL COOLING COMBINED WITH
MOISTENING DUE TO RAINFALL WILL CAUSE CIGS TO LOWER TO IFR LATE
TONIGHT. AS THE RAIN LIFTS NORTHEAST OF THE AREA LATER SUNDAY
MORNING...CIGS ARE EXPECTED TO IMPROVE TO MVFR. COLD ADVECTION
WILL INTENSIFY DURING THE EARLY EVENING AS HIGH PRESSURE BEGINS TO
BUILD INTO THE REGION FROM THE WEST. THIS WILL PRODUCE WEST TO
NORTHWESTERLY WINDS THAT WILL LIKELY GUST UP TO 25 KT THROUGH THE
EVENING. THIS COLD ADVECTION WILL ALSO HELP TO PRODUCE SCATTERED
SNOW SHOWERS IN THE AREA. IT ALSO APPEARS THAT CIGS WILL LOWER
BACK TO IFR DURING THE EVENING AS SNOW SHOWERS DEVELOP.
OUTLOOK...MVFR CEILINGS POSSIBLE WEDNESDAY AFTERNOON INTO
THURSDAY. MVFR TO IFR VISIBILITIES POSSIBLE THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
935 PM MST SAT DEC 28 2013
.UPDATE...
ISSUED AT 800 PM MST SAT DEC 28 2013
AFTERNOON RAP AS WELL AS LATEST RAP MODEL HAD FLURRIES COMING
DOWN FROM ND/MT AS WEAK SHORTWAVE DROPS INTO THE NORTHERN PLAINS.
LATEST RADAR/OBSERVATIONAL TRENDS SUPPORT...SO WILL HAVE FLURRIES
GOING OVER ENTIRE CWA ENTIRE NIGHT.
UPDATE ISSUED AT 557 PM MST SAT DEC 28 2013
LATEST RADAR TRENDS AS WELL AS SURFACE OBSERVATIONS SHOWED
-SN/--SN POPPING UP AS ARCTIC AIR SETTLES INTO THE CWA. WILL
INTRODUCE LOW POPS/FLURRIES TO SOUTHWEST 2/3RDS OF AREA FOR THIS
EVENING.
&&
.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 225 PM MST SAT DEC 28 2013
THE ARCTIC FRONT HAS ARRIVED FORCEFULLY AS HIGH WIND WARNING
CRITERIA HAVE BEEN MET ACROSS NWRN INTO WCNTRL SD AND 24-HR
TEMPERATURE DROPS OF -20 TO -40F ARE COMMON ACROSS THE CWA.
SNOWFALL HAS BEEN MINIMAL...AND CONFINED MOSTLY TO NERN WY AND FAR
NWRN SD AS CONFIRMED BY WEBCAMS AND SFC/RADAR OBS.
THE LATEST WATER VAPOR IMAGES SHOW THE UPPER TROUGH AXIS NEARING THE
NWRN CWA...AND RADAR IMAGES SHOW A FEW BANDS OF SNOW MOVING ACROSS
WCNTRL SD. THE STRONG SFC PRESSURE RISES OF 6-8 MB/3HR WERE CENTERED
OVER SCNTRL ND AND MOVING SOUTHEAST. THESE RISES ALSO HAVE BEEN
WEAKENING WITH TIME (MORESO THAN EXPECTED TO OCCUR WITH THE SEMI-
DIURNAL TIDE)...THUS THE WIND SPEEDS SHOULD TREND DOWNWARD OVER THE
NEXT SEVERAL HOURS. THE COLD ADVECTION STILL WAS QUITE STRONG ACROSS
THE CWA...AND WILL CONTINUE TO BE SO THROUGH THE EARLY EVENING. THIS
SUPPORTS THE WIND CHILL ADVY THAT IS IN EFFECT FOR NWRN SD TONIGHT.
ON THE LARGER-SCALE...THE SHORT-WAVE TROUGH WILL MOVE EAST OF THE
CWA OVERNIGHT AS ANOTHER ONE DROPS SOUTH ACROSS ND BY 12Z SUNDAY. A
SURFACE HIGH WILL BUILD OVER THE DAKOTAS...HELPING TO LESSEN THE
WINDS...BUT ALSO CONTINUING TO USHER COLD AIR INTO THE REGION. SNOW
SHOULD END FAIRLY QUICKLY THIS EVENING AS THE FORCING IS WEAK AND
MOISTURE IS MINIMAL. THE 850-MB TEMPS ALSO MAY RISE A FEW DEGREES BY
12Z AS THE COLDEST POCKET OF AIR IS PROGGED TO BE JUST SOUTHEAST OF
THE CWA.
ON SUNDAY A LEE TROF WILL DEVELOP OVER ERN WY IN RESPONSE TO THE
NEXT APPROACHING SHORT-WAVE TROUGH THAT WILL REACH ERN MT AND WY BY
24Z. THE RESULT WILL BE LOW-LEVEL WARM ADVECTION ACROSS MUCH OF THE
CWA AS THE TIGHT BAROCLINIC ZONE SHIFTS EASTWARD. A LACK OF MIXING
WILL PREVENT THIS WARM AIR FROM AFFECTING SURFACE TEMPERATURES OVER
THE ERN HALF OF THE CWA.
ON SUNDAY NIGHT THERE SHOULD BE A SLUG OF MIDLEVEL MOISTURE AS ONE
SHORT-WAVE TROUGH PASSES OVER THE CWA AND ANOTHER ONE FOLLOWS
QUICKLY BEHIND THE FIRST. THE SURFACE TROUGH WILL MOVE EAST AS
WELL...ENGENDERING MIXING AND STEADY/RISING TEMPERATURES OVERNIGHT.
SOME UPSLOPE SNOW APPEARS LIKELY...ALTHOUGH LOW-LEVEL MOISTURE WILL
LIMIT THE CHANCE OF SNOW ACROSS THE PLAINS.
&&
.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 225 PM MST SAT DEC 28 2013
ACTIVE NW FLOW THROUGH THE MIDDLE OF THE WEEK...WITH SEVERAL
SHORT-WAVE TROUGHS EXPECTED TO ADVECT SE ACROSS THE NORTHERN
PLAINS. POSITIVE HEIGHT ANOMALY OVER THE EASTERN PAC WILL
PERSIST...WITH RIDGE-TOPPING IMPULSES SQUELCHING THE RIDGE
AMPLITUDE AT TIMES. THE STRENGTH OF THE WESTERN CONUS RIDGE WILL
DICTATE THE LOCATION OF THE WAVERING FRONTAL BOUNDARY ACROSS THE
REGION...WITH THIS FEATURE LIKELY TO REMAIN GENERALLY ACROSS THE
FA THROUGH THE MIDDLE OF NEXT WEEK. WESTERN AREAS WILL TEND TO BE
AT OR ABOVE SEASONAL NORMS...WITH EASTERN AREAS REMAINING BELOW
NORMAL. DETERMINISTIC AND ENSEMBLE SOLUTIONS ARE SUPPORTING
ANOTHER RESURGENCE OF THE WESTERN CONUS RIDGE BY WED OF NEXT WEEK
AS THE SE CANADIAN NEGATIVE HEIGHT ANOMALY SHIFTS RAPIDLY EAST
GIVEN A STRONG ASSOCIATED NORTHERN-ATLANTIC UPPER JET. THIS WILL
ALLOW WARMER AIR TO SHIFT BACK EAST OFF THE ROCKIES AND INTO THE
NORTHERN PLAINS...UNTIL THE NEXT BUBBLE OF ARCTIC AIR ADVANCES
SOUTH TOWARD THE REGION THE FOLLOWING WEEKEND...BEING AIDED BY
ANOTHER POWERFUL NORTHERN PAC UPPER TROUGH...WITH THE CENTRAL
CANADIAN NEGATIVE HEIGHT ANOMALY DRIVING MOST OF THE PATTERN ONCE
AGAIN. THERE ARE GROWING INDICATIONS IN THE ECMWF FOR AN EASTWARD
EXTENSION OF THE EAST-ASIAN UPPER JET...WHICH WOULD SUPPORT
SUBSTANTIAL HEIGHT RISES OVER THE EASTERN PAC...AND A STRONGLY
POSITIVE PNA. A STRONG LEADING UPPER TROUGH WOULD BE POSSIBLE WITH
THIS TRANSITION...POSSIBLY SUPPORTING A WINTER STORM FOR THE
REGION. THIS IS HINTED AT IN THE LATEST SUCCESSIVE RUNS OF THE
ECMWF VALID FOR THE END OF NEXT WEEKEND.
MON-WED...SEVERAL NW FLOW IMPULSES EXPECTED...OF WHICH TIMING/
STRENGTH/AND TRACK VARIABILITY REMAINS. HAVE RETAINED LOW TO MID
RANGE POPS THROUGH MOST PERIODS FOR THESE DISTURBANCES...WITH NW
AREAS CONTINUING TO SEE THE BEST CHANCE FOR ANY SNOW ACCUMS...ESP
THE NORTHERN BLACK HILLS. THE MOST PERSISTENT AND STRONGEST
IMPULSE LOOKS TO REMAIN IN THE TUE PERIOD...THUS A POP RAISE WAS
WARRANTED. THE TEMP RANGE ACROSS THE FA WILL REMAIN QUITE LARGE
FROM WEST TO EAST...WITH EASTERN AREAS STRUGGLING TO SCOUR OUT THE
LL COLD AIR MASS.
THUR-SAT...WESTERN CONUS RIDGE WILL SHIFT EAST WITH A WARMER PATTERN
EXPECTED FOR THE FA...AS WESTERLY DOWNSLOPE FLOW PREVAILS. THIS WILL
SUPPORT DRY WEATHER...WITH TEMPS WARMING INTO THE 30S AND 40S WITH
SOME 50S CERTAINLY POSSIBLE IN THE LEE OF THE BLACK HILLS. THE RIDGE
WILL SHIFT EAST SAT...WITH A STRONG UPPER IMPULSE EXPECTED INTO THE
WESTERN CONUS. THIS SUPPORTS LOW POPS SAT ATTM. THE POTENTIAL FOR A
WINTER STORM REMAINS FOR SAT-SUN...GIVEN THE PATTERN SHIFT AND
STRONG LL BAROCLINIC ZONE EXPECTED. THIS WILL BEAR WATCHING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 931 PM MST SAT DEC 28 2013
AREAS MVFR CIGS WILL SLOWLY SHIFT SOUTH OF AREA OVERNIGHT LEAVING
VFR CONDITIONS/MID-CLOUDS WITH A FEW --SN. VFR CONDITIONS EXPECTED
SUNDAY WITH MID/HIGH CLOUDS...ALTHOUGH SOME MVFR CIGS WILL MOVE
ACROSS FAR NORTHWEST SD THROUGHOUT SUNDAY.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WIND CHILL ADVISORY UNTIL 10 AM MST SUNDAY FOR SDZ001-002-
012>014-032-073.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...BUNKERS
LONG TERM...JC
AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
921 PM CST MON DEC 30 2013
.UPDATE...FOR EVENING DISCUSSION.
&&
.DISCUSSION...
CLOUDS ARE BEGINNING TO PULL OUT OF THE MIDDLE TENNESSEE REGION AT
UPDATE TIME. SOME MID-LEVEL MOISTURE IS STILL LINGERING ACROSS THE
SOUTH AND EAST...AND WITH THE TEMPERATURE PROFILE OFF OF THE 00Z
KOHX SOUNDING COMPLETELY BELOW FREEZING AND SATURATED ABOVE
800MB...SOME FLURRIES COULD BE SQUEEZED OUT THROUGH MIDNIGHT OR
1 AM ACROSS THE PLATEAU. A DUSTING IS POSSIBLE...BUT EVEN SO...NO
HAZARDS ARE EXPECTED.
MADE SOME SMALL TWEAKS TO THE DEW POINT TRENDS FOR THE REST OF THE
OVERNIGHT...OTHERWISE THE FORECAST IS ON TRACK. UPDATE ON THE WAY.
UNGER
&&
.AVIATION...00Z TAF DISCUSSION.
SHORT WAVE VERY EVIDENT IN 700 MBAR THERMAL PATTERN FROM SOUTHERN
ILLINOIS DOWN THROUGH SOUTHEAST MISSOURI INTO NORTHWEST ARKANSAS
WITH GOOD +30 VORT MAX AT 400 MBAR STRUNG OUT WEST TO EAST ACROSS
SOUTHERN MISSOURI. LOWER TROPOSPHERIC MOISTURE BECOMING DEPLETED
IN TIME AS EVIDENT IN LATEST RUC RUN FROM TENNESSEE NORTHWARD.
ONCE VORT MAX SWINGS ACROSS MID STATE AROUND MIDNIGHT SHOULD SEE
SKIES BEGIN TO CLEAR FROM WEST TO EAST. FLYERS ARE LOOKING AT A
VFR FORECAST NEXT 24 HOURS.
BOYD
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
27
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
531 PM CST MON DEC 30 2013
.UPDATE...FOR 00Z AVIATION FORECAST
&&
.AVIATION...
SHORT WAVE VERY EVIDENT IN 700 MBAR THERMAL PATTERN FROM SOUTHERN
ILLINOIS DOWN THROUGH SOUTHEAST MISSOURI INTO NORTHWEST ARKANSAS
WITH GOOD +30 VORT MAX AT 400 MBAR STRUNG OUT WEST TO EAST ACROSS
SOUTHERN MISSOURI. LOWER TROPOSPHERIC MOISTURE BECOMING DEPLETED IN
TIME AS EVIDENT IN LATEST RUC RUN FROM TENNESSEE NORTHWARD. ONCE
VORT MAX SWINGS ACROSS MID STATE AROUND MIDNIGHT SHOULD SEE SKIES
BEGIN TO CLEAR FROM WEST TO EAST. FLYERS ARE LOOKING AT A VFR
FORECAST NEXT 24 HOURS.
BOYD
&&
.PREV DISCUSSION... /ISSUED 520 PM CST MON DEC 30 2013/
MESOSCALE UPDATE...
LIGHT SNOW/FLURRIES ARE FALLING INTO A VERY DRY LOWER TROPOSPHERE
ACROSS MIDDLE TENNESSEE WITH 850 MBAR DEWPOINT TEMPERATURES VERY
DRY AND WELL BELOW ZERO CELSIUS. THIS IS PRODUCING VIRGA. HOWEVER
NEAR AND SOUTH OF THE ALABAMA BORDER WHERE THE LOWER TROPOSPHERE
CONTAINS A LITTLE MORE MOISTURE DEWPOINT TEMPERATURES AT 850 MBAR
ARE AT OR ABOVE ZERO CELSIUS SO THERE IS A BETTER CHANCE OF
SEEING A FLURRY OR EVEN A LIGHT DUSTING NEAR THE ALABAMA BORDER
FROM WAYNE TO LAWRENCE AND GILES COUNTIES DURING THE EARLY
EVENING. NOT EXPECTING ANY ISSUES ON ROADS AT THIS TIME. PRECIP
SHOULD BEGIN TO PULL AWAY BY MID EVENING.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
235 AM EST TUE DEC 31 2013
.SYNOPSIS...
WEAK LOW PRESSURE MOVES EAST ACROSS THE CAROLINAS TONIGHT...THEN
PUSHES OFFSHORE TUESDAY MORNING. HIGH PRESSURE BUILDS BACK OVER
THE AREA TUESDAY AFTERNOON THROUGH WEDNESDAY. LOW PRESSURE MOVES
THROUGH THE OHIO AND TENNESSEE VALLEYS WEDNESDAY NIGHT AND
THURSDAY...BEFORE CROSSING THE REGION THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
QUICK LOOK AT THE 00Z NAM / HRRR AND 21Z SREF ALL SUGGEST PCPN WILL
HAVE A TUFF TIME GETTING TO FAR NORTH OVERNIGHT AS THE WEAK S/W
MOVES EAST ACROSS THE CAROLINAS. IN ADDITION...2M TEMPS SUGGEST
READINGS HOVER JUST ABOVE FREEZING OVER MOST OF SRN VA/NE NC. SO
MADE SOME ADDITIONAL CHANGES TO OVERNIGHT GRIDS BASED ON THE LATEST
DATA. KEPT A NARROW BAND OF A RAIN/SNOW SHOWER MIX ON NORTHERN
FRINGES OF THE PCPN SHIELD (FVX-PTB-JGG-MVF LINE) WITH JUST RAIN
OVER SOUTHERN / SERN VA AND NE NC COUNTIES. BUMPED UP POPS A BIT
ACROSS THE SOUTHERN AREAS TO 30% WITH .01 QPF AT THE MOST. CAA
ACROSS NRN MOST COUNTIES WILL ALLOW TEMPS TO DROP INTO THE U20S BY
12Z...RANGING INTO THE L-M30S SOUTHERN HALF OF FA.
PVS DSCN:
RAPIDLY DECREASING CLOUDS EXPECTED TUESDAY BEHIND SHORTWAVE WILL
ALLOW FOR A SUNNY/MOSTLY SUNNY DAY...AS HIGH PRESSURE BUILDS INTO
THE AREA. MAX TEMPS WILL BE SLIGHTLY COOLER THAN TODAY. HIGH TEMPS
IN THE MID TO UPR 40S NORTH...LOWER 50S NE NC/ EXTREME SRN VA.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
MOSTLY CLR AND SEASONABLY COLD TUESDAY NIGHT...WITH MIN TEMPS MOSTLY
IN THE 20S. SUNNY/MOSTLY SUNNY WEDNESDAY...WITH MAX TEMPS MID 40S
FAR NORTH...LOWER 50S SOUTH THIRD.
HIGH PRESSURE MOVES OFFSHORE WEDNESDAY NIGHT/THU...AS COMPLEX LOW
PRESSURE BEGINS DEVELOPING ACROSS MS VLY. THIS SYSTEM CONTINUES
ORGANIZING...AND MOVING ENEWD TOWARD THE REGION THU. GFS/ECMWF NOW
SUGGEST MORE WIDESPREAD PRECIP ACROSS THE AREA THU AFTERNOON...
CONTINUING INTO THU NIGHT. NAM MUCH DRIER/WEAKER WITH THIS
SYSTEM...AS IT DELAYS ANY SIFNIFICANT DEEPENING OF THE LOW UNTIL
AFTER 00Z FRIDAY. TEMPS ON THURSDAY IN THE 40S NORTH HALF TO THE
50-55 RANGE SE WILL KEEP ALL PRECIP LIQUID THROUGH 00Z FRI.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE LONG TERM PERIOD BEGINS THURSDAY EVENING WITH A COMPLEX LOW
PRESSURE SYSTEM IN VICINITY OF THE MID ATLANTIC STATES. MODELS ARE
BEGINNING TO CONVERGE ON A SOLUTION WHICH HAS THE MAIN LOW PRESSURE
DEVELOPING OVER THE TENNESSEE VALLEY AND MOVING THROUGH THE
CAROLINAS. THIS WOULD BRING THE POTENTIAL FOR WIDESPREAD PCPN
ACROSS THE AREA ON THURSDAY NIGHT. KEPT POPS IN THE CHC RANGE FOR
NOW UNTIL MODELS BECOME MORE CONSISTENT.
AFTER ABOVE NORMAL TEMPERATURES THURSDAY...TEMPERATURES FALL ON
THURSDAY NIGHT...WHICH WOULD CHANGE PCPN FROM RAIN TO SNOW FROM
NORTH TO SOUTH. PCPN MAY CHANGE TO ALL SNOW BY SHORTLY AFTER
MIDNIGHT N OF A LINE FROM EMPORIA TO WAKEFIELD TO WALLOPS ISLAND. BY
THAT TIME...DRYING MAY END OR DIMINISH PCPN ACROSS SOUTHERN AND
WESTERN PORTIONS OF THE AREA. IT APPEARS THAT THE GREATEST POTENTIAL
FOR ACCUMULATING SNOWFALL WILL BE ON THE LOWER MD EASTERN SHORE.
PCPN SHOULD END FROM W TO E EARLY FRIDAY BUT MAY CONTINUE INTO THE
AFTN ON THE EASTERN SHORE. IT IS TOO EARLY TO SPECULATE ON
ADDITIONAL DETAILS THIS FAR OUT.
THE LOW PRESSURE SYSTEM MOVES QUICKLY OUT TO SEA ON FRIDAY AND
INTENSIFIES RAPIDLY (BOMBS) SOUTHEAST OF NEW ENGLAND. THIS WILL
DRIVE ARCTIC AIR INTO THE AREA LATE FRIDAY AND FRIDAY NIGHT.
TEMPERATURES SATURDAY MORNING ON THE LOWER EASTERN SHORE AND
NORTHERN PORTIONS OF CENTRAL VIRGINIA MAY DROP INTO THE MID TO UPR
TEENS... ESPECIALLY WHERE THERE IS SNOW COVER.
HIGH PRESSURE SETTLES OVER THE AREA SATURDAY BEFORE MOVING OFF TO
THE EAST. TEMPERATURES GO BACK TO ABOVE NORMAL LEVELS BY SUNDAY
AHEAD OF THE NEXT COLD FRONT WHICH IS CURRENTLY PROGGED TO MOVE
THROUGH EARLY MONDAY WITH A CHC FOR SCATTERED SHOWERS. TEMPERATURES
DROP ONCE AGAIN EARLY NEXT WEEK AS A STRONG ARCTIC HIGH PRESSURE
OVER THE PLAINS STATES BEGINS TO BUILD TOWARD THE MID ATLANTIC
STATES.
HIGH TEMPERATURES MAINLY IN THE 30S FRIDAY AND SATURDAY WARM TO THE
UPR 40S NORTH TO 50S SOUTH SUNDAY AND MAINLY 50S MONDAY. LOWS FRIDAY
MORNING MID 20S TO LWR 30S LOWER TO MID TEENS TO LWR 20S SATURDAY
MORNING AND BY MONDAY MORNING IN THE 40S.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
VFR CONDS CONT TO PREVAIL AT THE TAF SITES ALTHOUGH WITH CIGS
AROUND 035-060 FT. WINDS ARE MOSTLY N-NE LESS THAN 10 KT. A WEAK
DISTURBANCE WILL MOVE NE ALONG A STRNY FRONT ACROSS NC TOWARDS
THE SE VA COAST EARLY THIS MORNING. THIS SYS IS EXPECTED TO
PRODUCE SOME -RA AND PSBL MVFR CIGS FOR ECG AND ORF. THE SYS WILL
CLEAR THE COAST BY SUNRISE AND SKIES WILL BECOME MOSTLY CLR BY
MID TO LATE MORNING.
HIGH PRESSURE BUILDS BACK IN LATE TODAY AND WEDNESDAY. THE NEXT
WEATHER SYSTEM AFFECTS THE AREA LATE THURSDAY INTO FRIDAY. EXPECT
AREAS OF RAIN...POSSIBLY TURNING TO LIGHT SNOW THURSDAY NIGHT
BEFORE ENDING. THERE IS UNCERTAINTY IN THE DETAILS BUT FOR NOW
HAVE A CHC FOR SNOW FRIDAY AT SBY. PERIODS OF MVFR/IFR CAN BE
EXPECTED DURING THIS PERIOD.
ARCTIC HIGH PRESSURE BUILDS INTO THE REGION LATE FRIDAY AND SATURDAY
WITH MAINLY CLEAR SKIES.
&&
.MARINE...
CDFNT POISED TO BE S AND E OF THE WTRS THIS EVE. INCRSD WINDSPEEDS
FM THE NNW MAKING THEIR WAY DN FM THE NRN PORTION OF THE
BAY...WHERE AT LEAST GUSTS TO LO END SCA HAVE BEEN NOTED. WILL
GIVE IT SOME TIME FOR SPEEDS TO INCRS HERE AS SFC HI PRES BEHIND
THE FNT MOVES BY JUST N OF THE WTRS THROUGH THIS EVE/ERY OVRNGT
PDS. WILL HOLD ONTO SCAS FOR THE BAY/LWR JAMES RVR BEFORE/THROUGH
MDNGT. LO LVL CAA WANES AFT MDNGT. SFC HI PRES WEAKENS OVR THE NE
CONUS BY TUE AFTN...RESULTING IN WNDS BECOMING MSTLY W. A SECOND
SURGE IN SPEEDS (SHORTLIVED) XPCD LT TUE AFTN/EVE BUT WILL KEEP
CONDS BLO SCA FOR NOW.
SFC HI PRES SLIDES ACRS THE WTRS WED...THEN OFFSHORE BY WED
NGT...W/ WNDS BECOMING MSTLY S (SPDS STAYING BLO 15 KT). MODEL
UNCERTAINTY AFFECTS THE CONFIDENCE OF THE FORECAST LT IN THE WK.
ANOTHER COASTAL STORM APPEARS TO IMPACT THE WATERS IN THE THURS-
FRI MORNING TIMEFRAME. 12Z/30 GFS/ECMWF BOTH DVLPG SGFNT CSTL LO
PRES E OF THE DELMARVA BY FRI MRNG. WILL HOLD OFF ON STRONG CAA
(AND SHARP INCRS IN WINDSPEEDS AND SEA/WAVE HGTS) POST STORM DVLPG
DURG FRI (PSBL GALES?)...WHICH WANES OVR THE WKND.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MPR
NEAR TERM...MPR
SHORT TERM...WRS
LONG TERM...LSA
AVIATION...MAS/JEF/LSA
MARINE...ALB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
350 AM EST TUE DEC 31 2013
.UPDATE...
ISSUED AT 905 PM EST MON DEC 30 2013
HEAVY LES BAND STILL APPEARS TO BE IMPACTING THE N 1/3 OF HOUGHTON
COUNTY AND FAR SOUTHERN KEWEENAW COUNTY. ISSUED A SPECIAL WX
STATEMENT FOR SOME MDT SN TOTALS OVER SRN KEWEENAW COUNTY.
CONSIDERED AN ADVY BASED ON RECENT REPORT OF SN ACCUMULATING AN
INCH/HR AT MOHAWK...BUT SUSPECT THE RESIDENCE TIME OF THE HEAVIER SN
THERE WL BE MORE LIMITED AS THE LLVL WINDS ARE FCST TO VEER MORE TO
THE NW LATER THIS EVNG. IN HOUGHTON COUNTY...THE HEAVY SN SHOULD
GRDLY SHIFT TO THE S AS THE LLVL FLOW VEERS.
ALSO EXPANDED THE WIND CHILL ADVY INTO MENOMINEE/DELTA COUNTIES
GIVEN EXPECTATION FOR CLRG/LOWER MIN TEMPS THERE FOLLOWING DEPARTURE
OF MID CLDS ASSOCIATED WITH DISTURBANCE PASSING TO THE S. LLVL WINDS
ARE FCST TO INCRS LATER TNGT WITH THE STRONGER CAD BEHIND THIS SYS.
ANY INCRS IN MIXING WL BE COUNTERED BY STRONGER ADVECTION OF THE
BITTERLY COLD AIRMASS UPSTREAM...WHERE TEMPS HAVE ALREADY FALLEN AOB
-30F AT SOME PLACES IN NRN MN.
OVER THE E...LES BANDS ARE STILL OFFSHORE. LATEST HI RES MODEL
GUIDANCE STILL SHOWS THESE BANDS COMING ONSHORE TOWARD LATE EVNG FM
GRAND MARAIS TO CRISP POINT...SO MAINTAINED GOING HEADLINES IN THIS
AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 430 PM EST MON DEC 30 2013
MOST OF UPPER MICHIGAN IS QUIET BUT COLD THIS AFTERNOON...AS THE
AREA IS UNDER LINGERING AFFECTS OF THE HIGH PRESSURE RIDGE THAT
MOVED THROUGH LAST NIGHT INTO THIS MORNING. THIS HAS LED TO WINDS
BACKING TO THE WEST-SOUTHWEST IN THE BOUNDARY LAYER AND FOCUSED THE
REMAINING LAKE EFFECT OVER THE KEWEENAW AND RIGHT ALONG THE
SHORELINE NEAR GRAND MARAIS. CALLS TO THE KEWEENAW THIS AFTERNOON
INDICATE THAT THE FINE FLAKE LES IS STILL IN PLACE. WHILE THIS IS
GOOD AT REDUCING VISIBILITIES...ACCUMULATIONS HAVE BEEN LIGHT AND
UNDER A COUPLE INCHES. OVER THE WEST...TEMPERATURES HAVE STRUGGLE
TO EVEN REACH ZERO DEGREES THIS AFTERNOON...WHICH WILL PAVE THE WAY
FOR ANOTHER NIGHT WILL COLD WIND CHILLS. FARTHER TO THE
SOUTHWEST...A SHORTWAVE IS SLIDING EAST-SOUTHEAST THROUGH MINNESOTA
AT THIS TIME AND IS LEADING TO LIGHT SNOW SHOWERS. THESE -SHSN
SHOULD MISS MUCH OF THE AREA...BUT COULD LEAD TO A FEW FLURRIES
ALONG THE WISCONSIN BORDER.
A WEAK SURFACE TROUGH OVER CENTRAL/SOUTHERN LAKE SUPERIOR AT THIS
TIME WILL BE THE FOCUS FOR THE LAKE EFFECT TONIGHT INTO TUESDAY
MORNING. ALL THE HIGH RESOLUTION MODELS SHOW A MESO-LOW DEVELOPING
OVER THE SOUTHEASTERN LAKE THIS EVENING. A LOOK AT THE MONTREAL
RIVER RADAR THIS AFTERNOON DOESN/T INDICATE ANY CIRCULATION AT THIS
POINT...BUT IT SHOULD BE DEVELOPING THIS EVENING. IN ADDITION...THE
LAKE EFFECT SNOW WILL BE ENHANCED BY A SHORTWAVE MOVING THROUGH THIS
EVENING. THIS WAVE PROVIDES A LITTLE MORE MOISTURE AND MID LEVEL
UPWARD MOTION...ALONG WITH COOLING ALOFT TO WEAKEN THE INVERSION
CURRENTLY AROUND 6-8KFT AND ALLOWS IT TO RISE TO 10-12KFT OVER THE
EASTERN CWA. ALSO...IT HELPS INTENSIFY THE SURFACE TROUGH OR
MESO-LOW OVER THE EASTERN LAKE BEFORE IT SLIDES SOUTHEAST LATE
TONIGHT INTO TUESDAY MORNING (BUT STILL LEAVES A TROUGH OVER THE
EASTERN LAKE). SINCE THIS HAS BEEN SHOWN FOR SEVERAL DAYS
NOW...FAIRLY CONFIDENT ON ITS OCCURRENCE...THE QUESTION COMES DOWN
TO EXACT LOCATION OF THE HEAVIEST BAND AND WHAT THE SNOW RATIOS WILL
BE. LATEST TRENDS IN THE MODELS SHOW A SLIGHTLY LATER ARRIVAL OF
THE STRONG LES BAND ON THE WEST SIDE OF THE MESO-LOW...LIKELY
CLOSER TO 04-06Z. UNFORTUNATELY THE LOCATION IS ALL OVER
THE MAP...WITH SOME HAVE IT HITTING PICTURED ROCKS (AND
NEARLY MUNISING - RAP AND A COUPLE 15Z HOPWRF MEMBERS) WHILE OTHERS
THE FAR NORTHEAST PART OF LUCE COUNTY (2.5 AND 10KM REGIONAL GEMS).
OPTED TO FOCUS ON THE MIDDLE GROUND WHICH WAS SIMILAR TO THE
PREVIOUS FORECAST AND HAVE THE STRONG BAND COME ONSHORE AROUND THE
GRAND MARAIS AREA. PINNING DOWN THIS LOCATION WILL MAKE OR BREAK
SNOWFALL AMOUNTS AND THE POTENTIAL OF REACHING WARNING SNOWFALL
AMOUNTS. ONCE THIS BAND COMES ON SHORE EXPECT A TRANSITION TO A
GENERAL NORTHWEST FLOW LES THROUGH THE DAY ON TUESDAY. WITH A
WEAK SURFACE TROUGH LINGERING OVER THE FAR EASTERN LAKE...MODELS
ARE INDICATING SOME ENHANCED CONVERGENCE TO LEAD TO A STRONGER BAND
AFFECTING NORTHERN LUCE COUNTY...ALTHOUGH THERE WILL BE SOME
WAVERING EXPECTED.
AS FOR SNOW RATIOS AND AMOUNTS...ARCTIC AIR MASS WILL LIKELY BE
MODIFIED SOMEWHAT FROM THE CIRCULATION AND MOISTURE/HEAT FLUX OFF
THE LAKE...WHICH WILL TRY TO PUT SOME OF THE CLOUD INTO THE DGZ.
THUS...WOULD EXPECT SOME HIGHER RATIOS TONIGHT AS THE BAND
COMES ON SHORE AND BEFORE SLIGHTLY COOLER AIR ARRIVES ON
TUESDAY AND TRANSITION BACK TO MORE OF A FINER FLAKE SNOW THAT
WE HAVE SEEN THE LAST 24-48HRS. ON TO AMOUNTS...PREVIOUS FORECAST
WAS RIGHT ON THE EDGE OF BOTH 12/24HR AMOUNTS AND HAVE SIMILAR IF
NOT SLIGHTLY LOWER VALUES FOR THIS FORECAST. THINK THERE WILL BE A
GOOD BURST WITH THAT STRONG BAND TONIGHT INTO TUESDAY MORNING OF 3
TO 7 INCHES. THEN THE TRANSITION TO MORE NORTHWEST WINDS AND
SLIGHTLY LOWER RATIOS SHOULD LEAD TO ANOTHER PERIOD OF 2-6 INCHES
FROM MID MORNING INTO THE EARLY EVENING (BUT LIKELY FOCUSED FARTHER
EAST INTO LUCE COUNTY). THIS IS JUST PUTS THE FORECAST JUST UNDER
BOTH THE 12/24HR WARNING AMOUNTS AND WITH THE UNCERTAINTY IN THE
EXACT LOCATION OF THE HEAVIEST SNOW...WILL ISSUE A STRONGLY WORDED
ADVISORY FOR ALGER/LUCE AND NORTHERN SCHOOLCRAFT FOR TONIGHT INTO
TUESDAY. THAT WAY WE CAN HOPEFULLY GET ONE MORE LOOK AT HIGH RES
RUNS AND IF THERE IS A BETTER HANDLE ON LOCATION AND CONFIDENCE
GROWS ON WARNING AMOUNTS...CAN UPGRADE THIS EVENING OR TONIGHT FOR
THE MORE SPECIFIC LOCATION. WITH ALL OF THE LOCATION
DIFFERENCES...WOULD HATE TO ISSUE A WARNING FOR LUCE AND THEN HAVE
IT STAY MAINLY IN ALGER OR VICE-VERSA.
OVER THE WEST...A SURFACE TROUGH STRETCHED WEST ACROSS SOUTHERN
LAKE SUPERIOR WILL SLOWLY PUSH THE MAIN BAND AFFECTING THE KEWEENAW
SOUTH TONIGHT INTO THE ONTONAGON AND SOUTHERN PORTIONS OF HOUGHTON
COUNTY AREA TONIGHT. AS THIS OCCURS...THE REST OF THE KEWEENAW WILL
TRANSITION TO MORE OF A NW FLOW LAKE EFFECT SCENARIO WHICH WILL
CONTINUE INTO TUESDAY. LESS RESIDENCE TIME OVER WESTERN LAKE
SUPERIOR WILL LIMIT THE ARCTIC AIR MASS MODERATION AND SHOULD KEEP
MOST OF THE CLOUD LAYER ABOVE THE DGZ. THUS...WOULD EXPECT THE
SMALLER SNOW FLAKES AND RATIOS TO CONTINUE THERE AND LIMIT
ACCUMULATIONS. INVERSION HEIGHTS ARE GREATER THAN THE PAST 24HRS
(7-9KFT) WHICH WILL LEAD TO SLIGHTLY STRONGER SHOWERS...BUT ALL OF
THAT CLOUD LAYER WILL BE WELL ABOVE THE DGZ. CURRENT THOUGHT IS
THERE BEING AN INCREASE IN SNOW ACCUMULATION THIS EVENING...BEFORE
COLDER 850MB TEMPS MOVE IN BEHIND THE SHORTWAVE (FALLING TO ALMOST
-26C BY 12Z TUESDAY) AND PUSH ALL OF THE CLOUD ABOVE THE DGZ.
ALTHOUGH TOTAL AMOUNTS OVER THE 24 HOUR PERIOD MAY REACH THE 3-6INCH
RANGE...THINK 12HR AMOUNTS WILL BE HARD PRESSED TO REACH THE 4 INCH
AMOUNT NEEDED FOR A LES ADVISORY.
A COLD START TO THE DAY AND A TIGHTENING SURFACE GRADIENT WITH THE
SURFACE DROPPING SOUTH INTO NORTHERN UPPER MICHIGAN TONIGHT WILL
LEAD TO ANOTHER NIGHT OF VERY COLD WIND CHILLS. THINK THE SCATTERED
HIGH CLOUDS AND SLIGHTLY HIGHER WINDS WILL KEEP TEMPS SLIGHTLY
WARMER THAN LAST NIGHT. BUT THIS WILL ALSO KEEP WIND CHILLS LOW AND
SIMILAR TO LAST NIGHT. THEREFORE...HAVE ISSUED A WIND CHILL
ADVISORY FOR THE SAME LOCATIONS AS LAST NIGHT AND HAVE IT RUNNING
THROUGH LATE TUESDAY MORNING. ONCE AGAIN...TEMPERATURES WILL
STRUGGLE TO REBOUND TOMORROW AND SOME LOCATIONS OUT WEST WILL STAY
IN THE SINGLE DIGITS BELOW ZERO.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 430 PM EST MON DEC 30 2013
MODELS ARE CONSISTENT IN SHOWING THE 500MB CLOSED LOW OVER QUEBEC
WEDNESDAY MOVING OFF INTO THE ATLANTIC THURSDAY. THE GFS /AS USUAL/
IS MORE PROGRESSIVE THAN THE ECWMF WITH THE LONGWAVE TROUGH IN THE
WAKE OF THE LOW...BRINGING THE TROUGH THROUGH THE GREAT LAKES ON
THURSDAY AFTERNOON. THE ECMWF IS SLOWER AND DEEPER WITH THIS
TROUGH...WITH IT BEING MAINLY OVER WI ON THURSDAY AFTERNOON.
GUIDANCE SUGGESTS THAT THE ECMWF HAS BEEN ERRING ON THE DEEPER AND
MORE AMPLIFIED SIDE LATELY...HOWEVER...AND THIS MAY BE THE CASE.
OVERALL WENT MIDDLE OF THE ROAD FOR THE FORECAST AT THIS
POINT...LEANING MORE TOWARDS THE ECMWF. AS FAR AS WHAT THIS MEANS
FOR THE SURFACE...LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS AND
RIDES NORTHEASTWARD ALONG THE TROUGH...WHICH BRINGS AN INVERTED
SURFACE TROUGH INTO UPPER MI FOR WEDNESDAY NIGHT-THURSDAY AFTERNOON.
TUESDAY NIGHT WINDS REMAIN OUT OF THE WEST NORTHWEST THROUGH
MIDNIGHT...BEFORE GRADUALLY VEERING TO THE NORTH AND EVEN NORTHEAST
AS THE INVERTED TROUGH SHIFTS WESTWARD. THIS MOVES THE HIGHEST POPS
FROM THE FAR NORTHEASTERN PORTIONS OF THE COUNTY TOWARDS MUNISING
THROUGH THE NIGHT. BY WEDNESDAY AFTERNOON...CONVERGENCE FOCUSES
BETWEEN MARQUETTE AND MUNISING...WHICH IS WHERE HIGHEST POPS ARE
SITUATED IN THE GRIDS. WHILE THIS REMAINS THE CASE THROUGH THURSDAY
AFTERNOON...TOTAL ACCUMULATIONS ARE GENERALLY EXPECTED TO BE ON THE
ORDER OF 2 TO 4 INCHES BETWEEN SHOT POINT AND MUNISING. GIVEN THAT
MOST OF THE BANDS ARE SHIFTING FROM WEST-NORTHWEST INTO A MORE
NORTH-NORTHEAST PATTERN THROUGH THE PERIOD...NOT REALLY EXPECTING
ANY ONE LOCATION TO RECEIVE TOO MUCH ACCUMULATION. ALSO...BEYOND
WEDNESDAY MORNING...WINDS AT 850-925MB BECOME SOMEWHAT MISALIGNED
WITH THE SURFACE WINDS...WHICH IS TYPICALLY LESS SUITABLE FOR MORE
STRUCTURED BANDS. THOUGH INVERSION HEIGHTS ARE HIGHER WITH COLDER
850MB TEMPS...GENERALLY UP TO 6-8KFT...THE DGZ IS LOW AND SO EXPECT
THE SAME SMALL SIZED FLAKES-AND LOW ACCUMULATIONS LIKE THOSE
OBSERVED ACROSS UPPER MI ALL WEEK/DESPITE SIMILAR INVERSION HEIGHTS.
THE NAM HINTS AT SOME HIGHER SNOW RATIOS OCCURRING IN THE
EAST...HOWEVER...THE NAM HAS BEEN TRENDING HIGHER THROUGH THIS PAST
WEEK THAN WHAT IS BEING OBSERVED. OVERALL...WEVE SEEN AROUND 18-20:1
RATIOS...AND THIS IS WHAT WAS USED FOR THE FORECAST. USING THE
NAM...THE BEST LIFT COLLOCATED WITH THE DGZ IS BETWEEN 6Z AND 15Z
WEDNESDAY AROUND MUNISING...AND SOME BIGGER FLAKES MAY BE SEEN
DURING THIS TIME. OTHERWISE...EXPECT ACCUMULATIONS TO RANGE FROM 1-3
INCHES NEAR THE LAKE FROM 6Z WEDNESDAY TO 12Z THURSDAY.
FRIDAY INTO SATURDAY LOW PRESSURE SLIDING OVER THE CANADIAN PRAIRIE
WILL SWING WINDS AROUND TO THE SOUTH ACROSS UPPER MI...PUSHING ALL
LAKE EFFECT SNOW BANDS OFF INTO LAKE SUPERIOR. 850MB TEMPS WARM AS
WELL...WITH THE ECMWF HINTING AT -8C TO -10C FOR BOTH DAYS. THE COLD
FRONT PASSES ON SATURDAY NIGHT. THE ARCTIC PUSH BEHIND THIS TROUGH
IS NOT TOO BAD...AS TEMPS 850MB TEMPS ARE SOMEWHAT RESCUED BY A
BRIEF RIDGE MOVING FROM THE NORTHERN PLAINS INTO THE GREAT LAKES
THROUGH SUNDAY AFTERNOON. KEPT BROAD CHANCE POPS ACROSS THE CWA FOR
MUCH OF THE FORECAST AREA THROUGH SATURDAY NIGHT. ON SUNDAY...TEMPS
ARE COLD ENOUGH AND WINDS OUT OF THE WEST-NORTHWEST...SO KEPT CHANCE
POPS CONFINED TO LAKE SUPERIOR.
THE MAIN DIFFERENCES BETWEEN MODELS LIE ON MONDAY...WITH THE ECMWF
AND THE GFS BOTH HINTING AT A VERY COLD ARCTIC PUSH OF AIR SLIDING
THROUGH...WITH 850MB TEMPS AS LOW AS -35C OVER UPPER MI. THOUGH THE
GFS IS NOT QUITE AS LOW...IT HAS 850MB TEMPS AT -25C TO -30C FOR THE
AREA. WILL TREND LOWER WITH TEMPS DURING THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1223 AM EST TUE DEC 31 2013
KIWD...AS WINDS VEER FM SW TO WNW IN THE WAKE OF A DISTURBANCE
PASSING TO THE S OF UPR MI...EXPECT SOME LK EFFECT CLDS/-SHSN TO
SPREAD BACK OVER THIS SITE BY SUNRISE. CONDITIONS SHOULD GRDLY
DETERIORATE FM VFR TO MVFR. IFR VSBYS ARE PSBL LATER IN THE DAY IF
THE FLOW VEERS FAR ENUF TO THE NW.
KCMX...VEERING W TO NW FLOW OF ARCTIC AIR WL ALLOW LK EFFECT -SHSN
TO IMPACT THIS LOCATION THIS FCST PERIOD. ALTHOUGH THERE COULD BE
SOME IMPROVEMENT IN VSBYS BTWN THE BANDS...IFR CONDITIONS SHOULD
PREDOMINATE.
SAW...WITH A DOWNSLOPE WSW FLOW OF DRY ARCTIC AIR VEERING TO WNW...
EXPECT VFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD EVEN THOUGH
OCNL FLURRIES/MVFR CIGS WL BE POSSIBLE THIS AFTN/EVNG.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 349 AM EST TUE DEC 31 2013
HEAVY FREEZING SPRAY WILL REMAIN A CONCERN FOR MAINLY CENTRAL AND
EASTERN LAKE SUPERIOR THROUGH EARLY WEDESDAY...AS AIR TEMPS CONTINUE TO
BE IN THE TEENS ABOVE ZERO TO THE SINGLE DIGITS BELOW ZERO...AND NW
TO N WINDS IN THE 20-30KT RANGE.
STRONG HIGH PRESSURE OVER SASKATCHEWAN WILL BUILD INTO MINNESOTA
TONIGHT...AND REMAIN NEARLY STATIONARY THROUGH THURSDAY.
OTHERWISE...THE PESKY LOW/TROUGH STRETCHING FROM EASTERN LAKE
SUPERIOR TO ALL OF SOUTHEASTERN ONTARIO WILL EXIT EASTWARD
TODAY...LEAVING A WEAKENING TROUGH ACROSS LAKE SUPERIOR THAT WILL
LINGER THROUGH THURSDAY...AS THE HIGH PRESSURE SYSTEM TO OUR WEST
SINKS INTO THE MID MISSISSIPPI VALLEY. EXPECT LOW PRESSURE ALONG THE
CENTRAL U.S./CANADIAN BORDER FRIDAY TO CROSS LAKE SUPERIOR AND
ONTARIO ON SATURDAY. AHEAD OF THIS LOW...S GUSTS OF 25-30KTS LATE
FRIDAY AFTERNOON INTO SATURDAY MORNING MAY JUMP UP TO GALES
/PARTICULARLY ACROSS E LAKE SUPERIOR FRIDAY NIGHT/.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR
MIZ002-004-005-009>013-084.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-085.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR MIZ003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST
WEDNESDAY FOR LSZ267.
HEAVY FREEZING SPRAY WARNING UNTIL 9 AM EST WEDNESDAY FOR LSZ243-
244-264-266.
HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST WEDNESDAY FOR LSZ248-
265.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
WEDNESDAY FOR LSZ241-242-263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ249-
250.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...SRF
LONG TERM...MCD
AVIATION...KC
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1223 AM EST TUE DEC 31 2013
.UPDATE...
ISSUED AT 905 PM EST MON DEC 30 2013
HEAVY LES BAND STILL APPEARS TO BE IMPACTING THE N 1/3 OF HOUGHTON
COUNTY AND FAR SOUTHERN KEWEENAW COUNTY. ISSUED A SPECIAL WX
STATEMENT FOR SOME MDT SN TOTALS OVER SRN KEWEENAW COUNTY.
CONSIDERED AN ADVY BASED ON RECENT REPORT OF SN ACCUMULATING AN
INCH/HR AT MOHAWK...BUT SUSPECT THE RESIDENCE TIME OF THE HEAVIER SN
THERE WL BE MORE LIMITED AS THE LLVL WINDS ARE FCST TO VEER MORE TO
THE NW LATER THIS EVNG. IN HOUGHTON COUNTY...THE HEAVY SN SHOULD
GRDLY SHIFT TO THE S AS THE LLVL FLOW VEERS.
ALSO EXPANDED THE WIND CHILL ADVY INTO MENOMINEE/DELTA COUNTIES
GIVEN EXPECTATION FOR CLRG/LOWER MIN TEMPS THERE FOLLOWING DEPARTURE
OF MID CLDS ASSOCIATED WITH DISTURBANCE PASSING TO THE S. LLVL WINDS
ARE FCST TO INCRS LATER TNGT WITH THE STRONGER CAD BEHIND THIS SYS.
ANY INCRS IN MIXING WL BE COUNTERED BY STRONGER ADVECTION OF THE
BITTERLY COLD AIRMASS UPSTREAM...WHERE TEMPS HAVE ALREADY FALLEN AOB
-30F AT SOME PLACES IN NRN MN.
OVER THE E...LES BANDS ARE STILL OFFSHORE. LATEST HI RES MODEL
GUIDANCE STILL SHOWS THESE BANDS COMING ONSHORE TOWARD LATE EVNG FM
GRAND MARAIS TO CRISP POINT...SO MAINTAINED GOING HEADLINES IN THIS
AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 430 PM EST MON DEC 30 2013
MOST OF UPPER MICHIGAN IS QUIET BUT COLD THIS AFTERNOON...AS THE
AREA IS UNDER LINGERING AFFECTS OF THE HIGH PRESSURE RIDGE THAT
MOVED THROUGH LAST NIGHT INTO THIS MORNING. THIS HAS LED TO WINDS
BACKING TO THE WEST-SOUTHWEST IN THE BOUNDARY LAYER AND FOCUSED THE
REMAINING LAKE EFFECT OVER THE KEWEENAW AND RIGHT ALONG THE
SHORELINE NEAR GRAND MARAIS. CALLS TO THE KEWEENAW THIS AFTERNOON
INDICATE THAT THE FINE FLAKE LES IS STILL IN PLACE. WHILE THIS IS
GOOD AT REDUCING VISIBILITIES...ACCUMULATIONS HAVE BEEN LIGHT AND
UNDER A COUPLE INCHES. OVER THE WEST...TEMPERATURES HAVE STRUGGLE
TO EVEN REACH ZERO DEGREES THIS AFTERNOON...WHICH WILL PAVE THE WAY
FOR ANOTHER NIGHT WILL COLD WIND CHILLS. FARTHER TO THE
SOUTHWEST...A SHORTWAVE IS SLIDING EAST-SOUTHEAST THROUGH MINNESOTA
AT THIS TIME AND IS LEADING TO LIGHT SNOW SHOWERS. THESE -SHSN
SHOULD MISS MUCH OF THE AREA...BUT COULD LEAD TO A FEW FLURRIES
ALONG THE WISCONSIN BORDER.
A WEAK SURFACE TROUGH OVER CENTRAL/SOUTHERN LAKE SUPERIOR AT THIS
TIME WILL BE THE FOCUS FOR THE LAKE EFFECT TONIGHT INTO TUESDAY
MORNING. ALL THE HIGH RESOLUTION MODELS SHOW A MESO-LOW DEVELOPING
OVER THE SOUTHEASTERN LAKE THIS EVENING. A LOOK AT THE MONTREAL
RIVER RADAR THIS AFTERNOON DOESN/T INDICATE ANY CIRCULATION AT THIS
POINT...BUT IT SHOULD BE DEVELOPING THIS EVENING. IN ADDITION...THE
LAKE EFFECT SNOW WILL BE ENHANCED BY A SHORTWAVE MOVING THROUGH THIS
EVENING. THIS WAVE PROVIDES A LITTLE MORE MOISTURE AND MID LEVEL
UPWARD MOTION...ALONG WITH COOLING ALOFT TO WEAKEN THE INVERSION
CURRENTLY AROUND 6-8KFT AND ALLOWS IT TO RISE TO 10-12KFT OVER THE
EASTERN CWA. ALSO...IT HELPS INTENSIFY THE SURFACE TROUGH OR
MESO-LOW OVER THE EASTERN LAKE BEFORE IT SLIDES SOUTHEAST LATE
TONIGHT INTO TUESDAY MORNING (BUT STILL LEAVES A TROUGH OVER THE
EASTERN LAKE). SINCE THIS HAS BEEN SHOWN FOR SEVERAL DAYS
NOW...FAIRLY CONFIDENT ON ITS OCCURRENCE...THE QUESTION COMES DOWN
TO EXACT LOCATION OF THE HEAVIEST BAND AND WHAT THE SNOW RATIOS WILL
BE. LATEST TRENDS IN THE MODELS SHOW A SLIGHTLY LATER ARRIVAL OF
THE STRONG LES BAND ON THE WEST SIDE OF THE MESO-LOW...LIKELY
CLOSER TO 04-06Z. UNFORTUNATELY THE LOCATION IS ALL OVER
THE MAP...WITH SOME HAVE IT HITTING PICTURED ROCKS (AND
NEARLY MUNISING - RAP AND A COUPLE 15Z HOPWRF MEMBERS) WHILE OTHERS
THE FAR NORTHEAST PART OF LUCE COUNTY (2.5 AND 10KM REGIONAL GEMS).
OPTED TO FOCUS ON THE MIDDLE GROUND WHICH WAS SIMILAR TO THE
PREVIOUS FORECAST AND HAVE THE STRONG BAND COME ONSHORE AROUND THE
GRAND MARAIS AREA. PINNING DOWN THIS LOCATION WILL MAKE OR BREAK
SNOWFALL AMOUNTS AND THE POTENTIAL OF REACHING WARNING SNOWFALL
AMOUNTS. ONCE THIS BAND COMES ON SHORE EXPECT A TRANSITION TO A
GENERAL NORTHWEST FLOW LES THROUGH THE DAY ON TUESDAY. WITH A
WEAK SURFACE TROUGH LINGERING OVER THE FAR EASTERN LAKE...MODELS
ARE INDICATING SOME ENHANCED CONVERGENCE TO LEAD TO A STRONGER BAND
AFFECTING NORTHERN LUCE COUNTY...ALTHOUGH THERE WILL BE SOME
WAVERING EXPECTED.
AS FOR SNOW RATIOS AND AMOUNTS...ARCTIC AIR MASS WILL LIKELY BE
MODIFIED SOMEWHAT FROM THE CIRCULATION AND MOISTURE/HEAT FLUX OFF
THE LAKE...WHICH WILL TRY TO PUT SOME OF THE CLOUD INTO THE DGZ.
THUS...WOULD EXPECT SOME HIGHER RATIOS TONIGHT AS THE BAND
COMES ON SHORE AND BEFORE SLIGHTLY COOLER AIR ARRIVES ON
TUESDAY AND TRANSITION BACK TO MORE OF A FINER FLAKE SNOW THAT
WE HAVE SEEN THE LAST 24-48HRS. ON TO AMOUNTS...PREVIOUS FORECAST
WAS RIGHT ON THE EDGE OF BOTH 12/24HR AMOUNTS AND HAVE SIMILAR IF
NOT SLIGHTLY LOWER VALUES FOR THIS FORECAST. THINK THERE WILL BE A
GOOD BURST WITH THAT STRONG BAND TONIGHT INTO TUESDAY MORNING OF 3
TO 7 INCHES. THEN THE TRANSITION TO MORE NORTHWEST WINDS AND
SLIGHTLY LOWER RATIOS SHOULD LEAD TO ANOTHER PERIOD OF 2-6 INCHES
FROM MID MORNING INTO THE EARLY EVENING (BUT LIKELY FOCUSED FARTHER
EAST INTO LUCE COUNTY). THIS IS JUST PUTS THE FORECAST JUST UNDER
BOTH THE 12/24HR WARNING AMOUNTS AND WITH THE UNCERTAINTY IN THE
EXACT LOCATION OF THE HEAVIEST SNOW...WILL ISSUE A STRONGLY WORDED
ADVISORY FOR ALGER/LUCE AND NORTHERN SCHOOLCRAFT FOR TONIGHT INTO
TUESDAY. THAT WAY WE CAN HOPEFULLY GET ONE MORE LOOK AT HIGH RES
RUNS AND IF THERE IS A BETTER HANDLE ON LOCATION AND CONFIDENCE
GROWS ON WARNING AMOUNTS...CAN UPGRADE THIS EVENING OR TONIGHT FOR
THE MORE SPECIFIC LOCATION. WITH ALL OF THE LOCATION
DIFFERENCES...WOULD HATE TO ISSUE A WARNING FOR LUCE AND THEN HAVE
IT STAY MAINLY IN ALGER OR VICE-VERSA.
OVER THE WEST...A SURFACE TROUGH STRETCHED WEST ACROSS SOUTHERN
LAKE SUPERIOR WILL SLOWLY PUSH THE MAIN BAND AFFECTING THE KEWEENAW
SOUTH TONIGHT INTO THE ONTONAGON AND SOUTHERN PORTIONS OF HOUGHTON
COUNTY AREA TONIGHT. AS THIS OCCURS...THE REST OF THE KEWEENAW WILL
TRANSITION TO MORE OF A NW FLOW LAKE EFFECT SCENARIO WHICH WILL
CONTINUE INTO TUESDAY. LESS RESIDENCE TIME OVER WESTERN LAKE
SUPERIOR WILL LIMIT THE ARCTIC AIR MASS MODERATION AND SHOULD KEEP
MOST OF THE CLOUD LAYER ABOVE THE DGZ. THUS...WOULD EXPECT THE
SMALLER SNOW FLAKES AND RATIOS TO CONTINUE THERE AND LIMIT
ACCUMULATIONS. INVERSION HEIGHTS ARE GREATER THAN THE PAST 24HRS
(7-9KFT) WHICH WILL LEAD TO SLIGHTLY STRONGER SHOWERS...BUT ALL OF
THAT CLOUD LAYER WILL BE WELL ABOVE THE DGZ. CURRENT THOUGHT IS
THERE BEING AN INCREASE IN SNOW ACCUMULATION THIS EVENING...BEFORE
COLDER 850MB TEMPS MOVE IN BEHIND THE SHORTWAVE (FALLING TO ALMOST
-26C BY 12Z TUESDAY) AND PUSH ALL OF THE CLOUD ABOVE THE DGZ.
ALTHOUGH TOTAL AMOUNTS OVER THE 24 HOUR PERIOD MAY REACH THE 3-6INCH
RANGE...THINK 12HR AMOUNTS WILL BE HARD PRESSED TO REACH THE 4 INCH
AMOUNT NEEDED FOR A LES ADVISORY.
A COLD START TO THE DAY AND A TIGHTENING SURFACE GRADIENT WITH THE
SURFACE DROPPING SOUTH INTO NORTHERN UPPER MICHIGAN TONIGHT WILL
LEAD TO ANOTHER NIGHT OF VERY COLD WIND CHILLS. THINK THE SCATTERED
HIGH CLOUDS AND SLIGHTLY HIGHER WINDS WILL KEEP TEMPS SLIGHTLY
WARMER THAN LAST NIGHT. BUT THIS WILL ALSO KEEP WIND CHILLS LOW AND
SIMILAR TO LAST NIGHT. THEREFORE...HAVE ISSUED A WIND CHILL
ADVISORY FOR THE SAME LOCATIONS AS LAST NIGHT AND HAVE IT RUNNING
THROUGH LATE TUESDAY MORNING. ONCE AGAIN...TEMPERATURES WILL
STRUGGLE TO REBOUND TOMORROW AND SOME LOCATIONS OUT WEST WILL STAY
IN THE SINGLE DIGITS BELOW ZERO.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 430 PM EST MON DEC 30 2013
MODELS ARE CONSISTENT IN SHOWING THE 500MB CLOSED LOW OVER QUEBEC
WEDNESDAY MOVING OFF INTO THE ATLANTIC THURSDAY. THE GFS /AS USUAL/
IS MORE PROGRESSIVE THAN THE ECWMF WITH THE LONGWAVE TROUGH IN THE
WAKE OF THE LOW...BRINGING THE TROUGH THROUGH THE GREAT LAKES ON
THURSDAY AFTERNOON. THE ECMWF IS SLOWER AND DEEPER WITH THIS
TROUGH...WITH IT BEING MAINLY OVER WI ON THURSDAY AFTERNOON.
GUIDANCE SUGGESTS THAT THE ECMWF HAS BEEN ERRING ON THE DEEPER AND
MORE AMPLIFIED SIDE LATELY...HOWEVER...AND THIS MAY BE THE CASE.
OVERALL WENT MIDDLE OF THE ROAD FOR THE FORECAST AT THIS
POINT...LEANING MORE TOWARDS THE ECMWF. AS FAR AS WHAT THIS MEANS
FOR THE SURFACE...LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS AND
RIDES NORTHEASTWARD ALONG THE TROUGH...WHICH BRINGS AN INVERTED
SURFACE TROUGH INTO UPPER MI FOR WEDNESDAY NIGHT-THURSDAY AFTERNOON.
TUESDAY NIGHT WINDS REMAIN OUT OF THE WEST NORTHWEST THROUGH
MIDNIGHT...BEFORE GRADUALLY VEERING TO THE NORTH AND EVEN NORTHEAST
AS THE INVERTED TROUGH SHIFTS WESTWARD. THIS MOVES THE HIGHEST POPS
FROM THE FAR NORTHEASTERN PORTIONS OF THE COUNTY TOWARDS MUNISING
THROUGH THE NIGHT. BY WEDNESDAY AFTERNOON...CONVERGENCE FOCUSES
BETWEEN MARQUETTE AND MUNISING...WHICH IS WHERE HIGHEST POPS ARE
SITUATED IN THE GRIDS. WHILE THIS REMAINS THE CASE THROUGH THURSDAY
AFTERNOON...TOTAL ACCUMULATIONS ARE GENERALLY EXPECTED TO BE ON THE
ORDER OF 2 TO 4 INCHES BETWEEN SHOT POINT AND MUNISING. GIVEN THAT
MOST OF THE BANDS ARE SHIFTING FROM WEST-NORTHWEST INTO A MORE
NORTH-NORTHEAST PATTERN THROUGH THE PERIOD...NOT REALLY EXPECTING
ANY ONE LOCATION TO RECEIVE TOO MUCH ACCUMULATION. ALSO...BEYOND
WEDNESDAY MORNING...WINDS AT 850-925MB BECOME SOMEWHAT MISALIGNED
WITH THE SURFACE WINDS...WHICH IS TYPICALLY LESS SUITABLE FOR MORE
STRUCTURED BANDS. THOUGH INVERSION HEIGHTS ARE HIGHER WITH COLDER
850MB TEMPS...GENERALLY UP TO 6-8KFT...THE DGZ IS LOW AND SO EXPECT
THE SAME SMALL SIZED FLAKES-AND LOW ACCUMULATIONS LIKE THOSE
OBSERVED ACROSS UPPER MI ALL WEEK/DESPITE SIMILAR INVERSION HEIGHTS.
THE NAM HINTS AT SOME HIGHER SNOW RATIOS OCCURRING IN THE
EAST...HOWEVER...THE NAM HAS BEEN TRENDING HIGHER THROUGH THIS PAST
WEEK THAN WHAT IS BEING OBSERVED. OVERALL...WEVE SEEN AROUND 18-20:1
RATIOS...AND THIS IS WHAT WAS USED FOR THE FORECAST. USING THE
NAM...THE BEST LIFT COLLOCATED WITH THE DGZ IS BETWEEN 6Z AND 15Z
WEDNESDAY AROUND MUNISING...AND SOME BIGGER FLAKES MAY BE SEEN
DURING THIS TIME. OTHERWISE...EXPECT ACCUMULATIONS TO RANGE FROM 1-3
INCHES NEAR THE LAKE FROM 6Z WEDNESDAY TO 12Z THURSDAY.
FRIDAY INTO SATURDAY LOW PRESSURE SLIDING OVER THE CANADIAN PRAIRIE
WILL SWING WINDS AROUND TO THE SOUTH ACROSS UPPER MI...PUSHING ALL
LAKE EFFECT SNOW BANDS OFF INTO LAKE SUPERIOR. 850MB TEMPS WARM AS
WELL...WITH THE ECMWF HINTING AT -8C TO -10C FOR BOTH DAYS. THE COLD
FRONT PASSES ON SATURDAY NIGHT. THE ARCTIC PUSH BEHIND THIS TROUGH
IS NOT TOO BAD...AS TEMPS 850MB TEMPS ARE SOMEWHAT RESCUED BY A
BRIEF RIDGE MOVING FROM THE NORTHERN PLAINS INTO THE GREAT LAKES
THROUGH SUNDAY AFTERNOON. KEPT BROAD CHANCE POPS ACROSS THE CWA FOR
MUCH OF THE FORECAST AREA THROUGH SATURDAY NIGHT. ON SUNDAY...TEMPS
ARE COLD ENOUGH AND WINDS OUT OF THE WEST-NORTHWEST...SO KEPT CHANCE
POPS CONFINED TO LAKE SUPERIOR.
THE MAIN DIFFERENCES BETWEEN MODELS LIE ON MONDAY...WITH THE ECMWF
AND THE GFS BOTH HINTING AT A VERY COLD ARCTIC PUSH OF AIR SLIDING
THROUGH...WITH 850MB TEMPS AS LOW AS -35C OVER UPPER MI. THOUGH THE
GFS IS NOT QUITE AS LOW...IT HAS 850MB TEMPS AT -25C TO -30C FOR THE
AREA. WILL TREND LOWER WITH TEMPS DURING THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1223 AM EST TUE DEC 31 2013
KIWD...AS WINDS VEER FM SW TO WNW IN THE WAKE OF A DISTURBANCE
PASSING TO THE S OF UPR MI...EXPECT SOME LK EFFECT CLDS/-SHSN TO
SPREAD BACK OVER THIS SITE BY SUNRISE. CONDITIONS SHOULD GRDLY
DETERIORATE FM VFR TO MVFR. IFR VSBYS ARE PSBL LATER IN THE DAY IF
THE FLOW VEERS FAR ENUF TO THE NW.
KCMX...VEERING W TO NW FLOW OF ARCTIC AIR WL ALLOW LK EFFECT -SHSN
TO IMPACT THIS LOCATION THIS FCST PERIOD. ALTHOUGH THERE COULD BE
SOME IMPROVEMENT IN VSBYS BTWN THE BANDS...IFR CONDITIONS SHOULD
PREDOMINATE.
SAW...WITH A DOWNSLOPE WSW FLOW OF DRY ARCTIC AIR VEERING TO WNW...
EXPECT VFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD EVEN THOUGH
OCNL FLURRIES/MVFR CIGS WL BE POSSIBLE THIS AFTN/EVNG.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 430 PM EST MON DEC 30 2013
WEST-NORTHWEST WINDS WILL VEER TO THE NORTHWEST TONIGHT AND BE IN
THE 15-25KT RANGE. THERE COULD BE SOME GUSTS TO 30KTS OVER THE
EASTERN LAKE AS A MESO-LOW DEVELOPS. THESE WINDS WILL CONTINUE TO
PRODUCE SOME AREAS OF HEAVY FREEZING SPRAY AND WILL CONTINUE THE
HEAVY FREEZING SPRAY WARNING INTO WEDNESDAY MORNING OVER THE EAST.
OTHERWISE...LIGHTER WINDS ARE EXPECTED WEDNESDAY AND THURSDAY
BEFORE AN INCREASE OUT OF THE SOUTHWEST ON FRIDAY AND FRIDAY NIGHT.
THERE COULD BE A FEW GALE FORCE GUSTS TO 35KTS WHEN THIS OCCURS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR
MIZ002-004-005-009>011-084.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-085.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR MIZ003.
WIND CHILL ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR
MIZ012-013.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ266.
HEAVY FREEZING SPRAY WARNING FROM 6 AM THIS MORNING TO 4 AM EST
WEDNESDAY FOR LSZ248-265.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST WEDNESDAY FOR LSZ243-
244-264.
HEAVY FREEZING SPRAY WARNING UNTIL 10 PM EST /9 PM CST/ THIS
EVENING FOR LSZ241-242-263.
HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST WEDNESDAY FOR LSZ249-
250.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...SRF
LONG TERM...MCD
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1252 AM EST TUE DEC 31 2013
.SYNOPSIS...
HIGH PRESSURE WILL BRING PARTLY CLOUDY SKIES AND COLD TEMPERATURES
TO THE REGION TONIGHT. WEAK LOW PRESSURE TRACKING ACROSS LOWER
ONTARIO WILL BRING SOME LIGHT SNOW TO THE AREA ON TUESDAY...WITH
LAKE EFFECT SNOWS DEVELOPING BEHIND THIS SYSTEM FOR TUESDAY NIGHT
AND WEDNESDAY MORNING. MORE WIDESPREAD SNOW IS EXPECTED TO DEVELOP
ON WEDNESDAY NIGHT AND THURSDAY...WITH THE POTENTIAL FOR MODERATE
ACCUMULATIONS.
&&
.NEAR TERM /THROUGH TODAY/...
LAKE EFFECT MOISTURE CONTS TO LINGER IN THE CENTRAL SOUTHERN TIER
OF NY AND NC PA. THERE LOOKS LIKE THERE WAS EVEN FINGER LAKES
MOISTURE GETTING DRAWN IN AS WELL. CONTINUING SUBSC AND WEAKENING
WINDS OVERNIGHT SHUD CUT OFF ALL THE LAKE EFFECT FLURRIES. BY 6Z
THE LATEST RAP MODEL HAS 925 MB WINDS GOING CALM SO HAVE FLURRIES
ENDING AT THIS TIME. OTHERWISE CLOUDS WILL STREAM IN OVERHEAD AS
UVV INCREASES AHEAD OF NEXT SMALL CLIPPER SYSTEM. ALL SYNOPTIC
MODELS SHOW THIS SYSTEM WORKING ACRS NY AND PA TUESDAY DURING THE
DAY. THE MAIN DYNAMICAL FEATURE ASSCTD WITH THIS WAVE WAS JET
STREAK WHICH WAS DROPPING INTO THE BASE OF THE UPPER TROF OVER THE
ERN LAKES BY 18Z TUE. NRN PA AND C NY ARE IN THE LEFT FRONT QUAD
OF THIS UPPER LEVEL JET AND THERE WAS SIGNIFICANT LIFTG.
HOWEVER...TYPICAL OF NRN BRANCH WAVES THERE WAS LITTLE MOISTURE.
SO NOT LOOKING AT MUCH SNOW ACC/S...MAYBE AN INCH AT BEST. MODELS
AGREE THAT LIGHT SNOW ARRIVES FROM W TO E BWTN 10 AND 13Z AND
EXITS IN THE AFTERNOON. AFTER THIS WAVE PASSES BY A COLD STRONG
WESTERLY FLOW OF AIR SETS UP IN THE LOW-LEVELS TRIGGERING MORE
LAKE EFFECT SNOWS. H85 TEMPS DROP TO -18C OR SO WITH DECENT
INSTABILITY. KEPT LES WATCH GOING FOR NRN ONEIDA CO AS EXACT PLACEMENT
OF THE LAKE ONTARIO SNOWBAND STILL IS UNCERTAIN. IN ADDTN...925 MB
AND 850 MB WINDS ARE QUITE STRG RUNNING OVER 30 KNOTS...MESOSCALE
AND EVEN SYNOPTIC MODELS ARE HINTING AT A LAKE ERIE BAND THAT CUD
EXTEND WELL INLAND ACRS THE SRN TIER OF NY AND INTO NE PA. I HAVE
CHC POPS FOR SNOW SHOWERS IN THESE AREAS TO COVER THIS BEGINNING
TUE PM.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
LES BAND SHUD BE GOING STRONG TMRW EVNG ACRS NRN SXNS OF THE FCST
AREA. PROFILES ARE PRETTY IMPRSV WITH HIGH INVERSION LVL AND GOOD
SIGS FOR SNOW GROWTH. UNCERTAINTY AS TO HOW FAR SOUTH THIS BAND
WILL GET...WITH SOME MDLS KEEPING ACTIVITY OVER FAR NRN ZONES OF
THE BGM CWA...WHILE OTHERS DROP THE BAND SEWD INTO ONON/MAD/SRN
ONEIDA. FOR NOW ISSUED THE LES WATCH FOR NRN ONEIDA WHERE OUR
CONFIDENCE IS GREATEST...AND MENTIONED THE POTENTIAL (IF THE BAND
DROPS SOUTH) IN THE HWO FOR THE AFOREMENTIONED COUNTIES.
OPERATIONAL MDLS ARE TRENDING SLOWER AND DEEPER WITH THE UPR LVL
TROF DIGGING INTO THE ERN U.S. ON THURSDAY...AND ISENTROPIC LIFT
DVLPNG N OF THE ARCTIC FNTL BNDRY. STRONG HIGH PRES OVER QUEBEC
WILL KEEP THE COLD AIR LOCKED IN PLACE. A RATHER PROLONGED PD OF
SNOW LOOKS LIKELY TO BEGIN ON WED AND CONTINUE INTO THU...PRBLY INCRSNG
IN INTENSITY ON THU. NICE SIGS IN THE QVEC AND FGEN FIELDS...WITH
PROFILES LOOKING GOOD FOR SNOW GROWTH. SNOW RATIOS SHUD ALSO BE
RATHER HIGH GIVEN THE COLD AIR MASS. AT THIS POINT WILL CONTINUE
TO MENTION POTNL IN THE HWO.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
3 PM MON UPDATE... SYNOPTIC SNOWFALL EVENT SHOULD BE ONGOING THU
NGT...PERHAPS LINGERING INTO FRI. THERE ARE STILL PLENTY OF MODEL
DISCREPANCIES WITH THIS STORM...AS THE 12Z EC REMAINS THE MOST
AMPLIFIED AND SLOWEST WITH THE MAIN UPPER-LVL TROUGH AXIS...WHILE
THE GFS/CAN GEM ARE MORE PROGRESSIVE. ATTM...WPC IS LEANING TWDS
THE MORE PROGRESSIVE SOLNS...GIVEN THE PROGGED CANADIAN MARITIME
UPPER-LVL LOW...AND THE CONFLUENT PATN UNDERNEATH IT...WHICH SEEMS
REASONABLE AT THIS EARLY VANTAGE PT. EVEN SO...NICE WAA/FGEN FORCING
INTO THU NGT...FOLLOWED BY BRIEF DEFORMATION BAND MECHANICS INTO
EARLY FRI...LIKELY TRANSLATES TO AT LEAST WIDESPREAD ADVSY LVL
SNOW ACCUMS. STAY TUNED...AS MANY DETAILS ARE YET BE IRONED OUT.
THE OTHER MAIN STORY THIS PD IS THE ARCTIC AMS EXPECTED TO PLUNGE
SWD INTO CNY/NE PA FRI INTO SAT. IF ANYTHING...THE MODELS HAVE
TRENDED EVEN COLDER IN RECENT RUNS...WITH BOTH THE GFS/EC SHOWING
TEMPS NOT MUCH ABV ZERO FRI...THEN WELL BLO ZERO FRI NGT/EARLY
SAT. WE`VE BEEN ADVERTISING SINGLE DIGIT HIGHS ON FRI...WITH WELL
BLO ZERO READINGS FRI NGT/SAT MRNG...SO WE DIDN`T MAKE MANY CHGS
HERE. WE DID NUDGE TEMPS LWR LTR IN THE WEEKEND INTO EARLY NEXT
WEEK...TO BETTER MATCH THE LATEST STATISTICAL GUIDANCE.
MAINLY DRY WX IS STILL FORESEEN AT THE BEGINNING OF THE
WEEKEND...WHEN THE DEEPEST COLD WILL LIKELY BE IN PLACE. FROM SUN
INTO EARLY NEXT WEEK...ADDITIONAL NRN STREAM SHRT WV/FRNTL
PASSAGES ARE LIKELY...SO WE`VE JUST GONE WITH A GENERIC CHC OF
SHSN/FLRYS FOR NOW. AS WE DRAW CLOSER IN TIME...HOPEFULLY WE`LL
GET A BETTER FEEL FOR WHERE THE MOST PERSISTENT LES BANDS MAY SET
UP.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
06Z UPDATE...
CLOUDY SKIES WILL PERSIST THROUGH THIS MORNING WITH MOSTLY VFR
CIGS FROM 3-5 KFT. MVFR TO VFR CIGS WILL CONTINUE THROUGH TUESDAY
AFTERNOON WITH SNOW SHOWERS DEVELOPING. A FEW HEAVIER SNOW
SHOWERS WILL BRIEFLY LOWER CONDITIONS TO IFR BETWEEN 18Z AND 22Z.
LAKE EFFECT SNOW WILL DEVELOP NEAR AND NORTH OF THE THRUWAY LATE
TUESDAY AFTERNOON AND TUESDAY EVENING POSSIBLY BRINGING SOME HEAVY
SNOW TO THE RME TAF SITE... OTHERWISE THIS SNOW WILL REMAIN NORTH
OF THE REST OF THE TAF SITES THROUGH TUESDAY NIGHT.
WINDS WILL BE LIGHT AND VARIABLE EARLY THIS MORNING... THE WEST-
SOUTHWEST AT 10 TO 15 KTS WITH GUSTS TO 20 KTS THIS AFTERNOON INTO
THIS EVENING. WEST WINDS WILL CONTINUE AROUND 10 KTS LATE TUESDAY
NIGHT.
OUTLOOK...
WED...MVFR/IFR SHSN IN KSYR/KRME...WITH MAINLY VFR ELSEWHERE.
WED NGT-THU NGT...IFR SNOW LIKELY AREA-WIDE.
FRI...LINGERING RESTRICTIONS PSBL IN SHSN.
FRI NGT/SAT...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW WATCH FROM THIS AFTERNOON THROUGH WEDNESDAY
MORNING FOR NYZ009.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...
LONG TERM...MLJ
AVIATION...MSE/PVN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
750 AM MST TUE DEC 31 2013
.UPDATE...
ISSUED AT 746 AM MST TUE DEC 31 2013
BASED ON LATEST OBS EXTENDED THE LIFR FOG IN KALS UNTIL 16Z. VIS
SHOULD IMPROVE AFTER 16Z WITH LIFR CIGS BREAKING BY 17Z. -KT
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM MST TUE DEC 31 2013
NEXT SHORTWAVE WILL BE RIDING THROUGH NORTHWEST FLOW ALOFT INTO
NORTHWEST COLORADO LATE TONIGHT. AHEAD OF THIS SYSTEM TODAY SHOULD
BE A WARM DAY WITH TEMPERATURES CLIMBING INTO THE 50S. ALREADY
STARTING TO SEE SOME WAVE CLOUDINESS AND THESE WILL CONTINUE TO
THICKEN AND SPREAD EASTWARD AS MORE MOISTURE EVIDENT IN WV PICS
CONTINUES TO STREAM IN FROM THE NORTHWEST THIS MORNING. THIS WILL
SERVE TO CUT BACK ON MAX TEMPS A BIT THIS AFTERNOON IN SOME
PLACES...ESPECIALLY ALONG THE ARKANSAS RIVER VALLEY WHERE WINDS MAY
HAVE A HARDER TIME MIXING DOWN. HRRR DEPICTS THIS IN SFC T FIELDS
NICELY. OTHER AREA WHERE TEMPS WILL REALLY STRUGGLE WILL BE ACROSS
THE SAN LUIS VALLEY WHERE SNOW COVER HAS ALREADY DROPPED MAX TEMPS
DOWN TO AROUND 10 BELOW ZERO THIS MORNING. DEPENDING ON HOW QUICKLY
AND THICKLY HIGH CLOUDS SPREAD IN LATER THIS MORNING...TEMPERATURES
MAY STRUGGLE TO GET INTO THE MID/UPPER TEENS. HAVE CUT BACK ON MAX
TEMPS THERE CONSIDERABLY OVER GUIDANCE. MEANWHILE FOG IN THE SAN
LUIS VALLEY SHOULD THIN SOME AS HIGH CLOUDINESS MOVES IN THROUGH THE
MORNING...THEN DISSIPATE ENTIRELY BY 16Z. MEANWHILE...CENTRAL
MOUNTAINS WILL SEE OROGRAPHIC SNOW SHOWERS SPREAD IN DURING THE
MORNING...THEN DECREASE A BIT TOWARDS AFTERNOON. ANY ACCUMULATIONS LOOK
LIGHT AT THIS POINT...AND CONFINED MOSTLY TO THE HIGHER ELEVATIONS
OF THE SAWATCH AND MOSQUITO RANGES.
TONIGHT...SNOW SHOULD START TO RAMP UP ALONG THE CONTINENTAL DIVIDE
TOWARDS 06Z...WITH A FEW SNOW SHOWERS POSSIBLY SPREADING INTO THE
HIGHER PEAKS OF THE SANGRES TOWARDS 12Z. HEAVIEST ACCUMULATIONS
WILL STAY CONFINED TO THE CENTRAL MOUNTAINS WHERE ANOTHER 1 TO 3
INCHES WILL BE POSSIBLE OVERNIGHT. WESTERLY WINDS INTO THE LEE SIDE
SFC LOW WILL KEEP MIN TEMPS WARM ALONG THE LOWER EASTERN SLOPES OF
THE SE MTS. A COLD FRONT WILL DROP THROUGH THE SOUTHEAST PLAINS
AFTER 09Z BRINGING AN INCREASE IN NORTH WINDS TOWARDS DAWN. GFS AND
ECMWF APPEAR TO HAVE TRENDED TOWARDS A MORE AMPLIFIED SOLN WITH THE
UPPER TROF AS IT MOVES ACROSS SE CO TOWARDS MORNING...BUT FOR NOW
THINK ANY LIGHT PRECIP WILL HOLD OFF UNTIL AFTER 12Z. -KT
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 516 AM MST TUE DEC 31 2013
NOT MANY METEOROLOGICAL ADJUSTMENTS NEEDED DURING THE LONGER TERM
WITH PRIMARY CONCERNS CONTINUING TO BE POPS...GUSTY WINDS AT TIMES
AND TEMPERATURES.
RECENT LONGER TERM COMPUTER SIMULATIONS INDICATES THAT A COUPLE
OF UPPER DISTURBANCES WILL CROSS THE FORECAST DISTRICT DURING THE
LONGER TERM WITH THE INITIAL SYSTEM IMPACTING THE CWFA NEW YEARS
DAYS AND ANOTHER SYSTEM IMPACTING SOUTHERN COLORADO DURING THE
WEEKEND.
THEN GENERALLY DRY AND MILD TO WARM CONDITIONS SHOULD DEVELOP
OVER THE FORECAST DISTRICT FROM THURSDAY INTO FRIDAY AS DRY
NORTHWESTERLY UPPER FLOW IMPACTS SOUTHERN COLORADO.
A RETURN TO COOLER AND UNSETTLED CONDITIONS IS THEN ANTICIPATED
THIS WEEKEND AS ANOTHER UPPER DISTURBANCE IMPACTS THE FORECAST
DISTRICT. FINALLY...GUSTY WINDS WILL BE POSSIBLE OF MANY LOCATIONS
FROM WEDNESDAY INTO WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 516 AM MST TUE DEC 31 2013
LIFR CONDITIONS IN STRATUS/FOG WILL CONTINUE AT KALS (EVIDENT IN NOT
ONLY THE KALS SFC OB...BUT ALSO IN THE CDOT WEB CAMS AT ALAMOSA AND
VILLA GROVE) THIS MORNING. HOWEVER...AS HIGH CLOUDS SPREAD IN
TOWARDS 12-14Z...SUSPECT THAT VISIBILITIES WILL INCREASE AROUND THAT
TIME...WITH LIFR CONDITIONS COMING TO AN END BETWEEN 14-15Z. MAY
HAVE TO TWEAK THE KALS TAF FOR TIMING AS NEEDED THIS MORNING.
OTHERWISE...VFR CONDITIONS EXPECTED...WITH BOUTS OF MID-HIGH LEVEL
WAVE CLOUDINESS SPREADING IN ACROSS THE TAF SITES THROUGH THE DAY.
THE CENTRAL MOUNTAINS WILL SEE SOME SCATTERED SNOW SHOWERS WITH MTN
OBSCURATIONS AT TIMES TODAY. TONIGHT...A COLD FRONT WILL DROP
THROUGH KCOS AND KPUB BETWEEN 09Z-12Z BRINGING A WIND SHIFT FROM THE
NORTH TO NORTHWEST AT AROUND 10-20 KTS. MEANWHILE...INCREASING
CLOUDINESS AHEAD OF THE NEXT SYSTEM MOVING IN TONIGHT SHOULD PREVENT
FOG FROM REDEVELOPING ACROSS THE SAN LUIS VALLEY. CIGS AT THE TAF
SITES WILL LIKELY REMAIN VFR. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
517 AM MST TUE DEC 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM MST TUE DEC 31 2013
NEXT SHORTWAVE WILL BE RIDING THROUGH NORTHWEST FLOW ALOFT INTO
NORTHWEST COLORADO LATE TONIGHT. AHEAD OF THIS SYSTEM TODAY SHOULD
BE A WARM DAY WITH TEMPERATURES CLIMBING INTO THE 50S. ALREADY
STARTING TO SEE SOME WAVE CLOUDINESS AND THESE WILL CONTINUE TO
THICKEN AND SPREAD EASTWARD AS MORE MOISTURE EVIDENT IN WV PICS
CONTINUES TO STREAM IN FROM THE NORTHWEST THIS MORNING. THIS WILL
SERVE TO CUT BACK ON MAX TEMPS A BIT THIS AFTERNOON IN SOME
PLACES...ESPECIALLY ALONG THE ARKANSAS RIVER VALLEY WHERE WINDS MAY
HAVE A HARDER TIME MIXING DOWN. HRRR DEPICTS THIS IN SFC T FIELDS
NICELY. OTHER AREA WHERE TEMPS WILL REALLY STRUGGLE WILL BE ACROSS
THE SAN LUIS VALLEY WHERE SNOW COVER HAS ALREADY DROPPED MAX TEMPS
DOWN TO AROUND 10 BELOW ZERO THIS MORNING. DEPENDING ON HOW QUICKLY
AND THICKLY HIGH CLOUDS SPREAD IN LATER THIS MORNING...TEMPERATURES
MAY STRUGGLE TO GET INTO THE MID/UPPER TEENS. HAVE CUT BACK ON MAX
TEMPS THERE CONSIDERABLY OVER GUIDANCE. MEANWHILE FOG IN THE SAN
LUIS VALLEY SHOULD THIN SOME AS HIGH CLOUDINESS MOVES IN THROUGH THE
MORNING...THEN DISSIPATE ENTIRELY BY 16Z. MEANWHILE...CENTRAL
MOUNTAINS WILL SEE OROGRAPHIC SNOW SHOWERS SPREAD IN DURING THE
MORNING...THEN DECREASE A BIT TOWARDS AFTERNOON. ANY ACCUMULATIONS LOOK
LIGHT AT THIS POINT...AND CONFINED MOSTLY TO THE HIGHER ELEVATIONS
OF THE SAWATCH AND MOSQUITO RANGES.
TONIGHT...SNOW SHOULD START TO RAMP UP ALONG THE CONTINENTAL DIVIDE
TOWARDS 06Z...WITH A FEW SNOW SHOWERS POSSIBLY SPREADING INTO THE
HIGHER PEAKS OF THE SANGRES TOWARDS 12Z. HEAVIEST ACCUMULATIONS
WILL STAY CONFINED TO THE CENTRAL MOUNTAINS WHERE ANOTHER 1 TO 3
INCHES WILL BE POSSIBLE OVERNIGHT. WESTERLY WINDS INTO THE LEE SIDE
SFC LOW WILL KEEP MIN TEMPS WARM ALONG THE LOWER EASTERN SLOPES OF
THE SE MTS. A COLD FRONT WILL DROP THROUGH THE SOUTHEAST PLAINS
AFTER 09Z BRINGING AN INCREASE IN NORTH WINDS TOWARDS DAWN. GFS AND
ECMWF APPEAR TO HAVE TRENDED TOWARDS A MORE AMPLIFIED SOLN WITH THE
UPPER TROF AS IT MOVES ACROSS SE CO TOWARDS MORNING...BUT FOR NOW
THINK ANY LIGHT PRECIP WILL HOLD OFF UNTIL AFTER 12Z. -KT
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 516 AM MST TUE DEC 31 2013
NOT MANY METEOROLOGICAL ADJUSTMENTS NEEDED DURING THE LONGER TERM
WITH PRIMARY CONCERNS CONTINUING TO BE POPS...GUSTY WINDS AT TIMES
AND TEMPERATURES.
RECENT LONGER TERM COMPUTER SIMULATIONS INDICATES THAT A COUPLE
OF UPPER DISTURBANCES WILL CROSS THE FORECAST DISTRICT DURING THE
LONGER TERM WITH THE INITIAL SYSTEM IMPACTING THE CWFA NEW YEARS
DAYS AND ANOTHER SYSTEM IMPACTING SOUTHERN COLORADO DURING THE
WEEKEND.
THEN GENERALLY DRY AND MILD TO WARM CONDITIONS SHOULD DEVELOP
OVER THE FORECAST DISTRICT FROM THURSDAY INTO FRIDAY AS DRY
NORTHWESTERLY UPPER FLOW IMPACTS SOUTHERN COLORADO.
A RETURN TO COOLER AND UNSETTLED CONDITIONS IS THEN ANTICIPATED
THIS WEEKEND AS ANOTHER UPPER DISTURBANCE IMPACTS THE FORECAST
DISTRICT. FINALLY...GUSTY WINDS WILL BE POSSIBLE OF MANY LOCATIONS
FROM WEDNESDAY INTO WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 516 AM MST TUE DEC 31 2013
LIFR CONDITIONS IN STRATUS/FOG WILL CONTINUE AT KALS (EVIDENT IN NOT
ONLY THE KALS SFC OB...BUT ALSO IN THE CDOT WEB CAMS AT ALAMOSA AND
VILLA GROVE) THIS MORNING. HOWEVER...AS HIGH CLOUDS SPREAD IN
TOWARDS 12-14Z...SUSPECT THAT VISIBILITIES WILL INCREASE AROUND THAT
TIME...WITH LIFR CONDITIONS COMING TO AN END BETWEEN 14-15Z. MAY
HAVE TO TWEAK THE KALS TAF FOR TIMING AS NEEDED THIS MORNING.
OTHERWISE...VFR CONDITIONS EXPECTED...WITH BOUTS OF MID-HIGH LEVEL
WAVE CLOUDINESS SPREADING IN ACROSS THE TAF SITES THROUGH THE DAY.
THE CENTRAL MOUNTAINS WILL SEE SOME SCATTERED SNOW SHOWERS WITH MTN
OBSCURATIONS AT TIMES TODAY. TONIGHT...A COLD FRONT WILL DROP
THROUGH KCOS AND KPUB BETWEEN 09Z-12Z BRINGING A WIND SHIFT FROM THE
NORTH TO NORTHWEST AT AROUND 10-20 KTS. MEANWHILE...INCREASING
CLOUDINESS AHEAD OF THE NEXT SYSTEM MOVING IN TONIGHT SHOULD PREVENT
FOG FROM REDEVELOPING ACROSS THE SAN LUIS VALLEY. CIGS AT THE TAF
SITES WILL LIKELY REMAIN VFR. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
1023 AM EST TUE DEC 31 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE CROSS THE AREA EARLY TONIGHT AND
REINFORCE THE ARCTIC AIR IN THE THE REGION THROUGH NEW YEARS DAY.
LOW PRESSURE WILL PASS TO THE SOUTH OF NEW ENGLAND THURSDAY AND
WILL LIKELY DELIVER ACCUMULATING SNOWFALL TO THE AREA THURSDAY AND
THURSDAY NIGHT. VERY COLD TEMPERATURES ARE EXPECTED TO BE A BIG
THEME FOR THE REST OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1015 AM...A QUICK UPDATE TO INTRODUCE SOME FLURRIES ALONG THE
ME COAST TODAY...AS WEAK OCEAN EFFECT IS PRODUCING SOME LIGHT
ECHOES INTO YORK AND CUMBERLAND COUNTIES. STILL NO REPORTS OF ANY
SNOW...BUT WILL LKLY SEE SOME SNOW FLAKES IN THE AIR AT THE VERY
LEAST. BOTH RAP AND LOCAL WRF PICKING UP ON THIS...AND SHIFT THIS
FEATURE EWD THIS AFTERNOON AS THE SW FLOW AHEAD OF APPROACHING
COLD FRONT PICKS UP AND MOVES EWD AS WELL. PREV FORECAST OF COLD
FROPA LATE TODAY INTO THIS EVENING STILL ON TRACK...WITH SOME SCT
SHSN DEVELOPING...MAINLY IN THE MTNS...AND PERHAPS A DUSTING TO AN
INCH OF LIGHT FLUFFY SNOW IN SOME SPOTS OF THE WRN ME MTNS AND
HIGHER TERRAIN OF NH.
PREV DISC...
1025 MILLIBAR HIGH WILL BUILD EAST ACROSS THE AREA THIS MORNING. A
1014 MILLIBAR LOW OVER THE UPPER GREAT LAKES AND ASSOCIATED UPPER
IMPULSE WILL RACE EAST AND SPREAD SOME CLOUDS AND SCATTERED SNOW
SHOWERS INTO WESTERN AND NORTHERN SECTIONS TOWARDS DUSK. AFTER A
VERY CHILLY START...TEMPERATURES WILL STRUGGLE TO 5 TO 10 ABOVE
ACROSS THE MOUNTAINS WITH ONLY TEENS FOR THE REMAINDER...CLOSE TO
15 DEGREES BELOW AVERAGE FOR THE DATE. CHILL WILL NOT BE AS BIG A
FACTOR TODAY AS THE WINDS CONTINUE TO DIMINISH UNDER BUILDING HIGH
WITH WIND CHILL ADVISORY BEING ALLOWED TO EXPIRE ON SCHEDULE AT 12Z,
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
THE WEAK LOW TRAVERSES THE AREA EARLY TONIGHT WITH TRAILING COLD
FRONT PRESSING SOUTHWARD ACROSS THE REGION. WE`LL SEE A FEW CLOUDS
AS WELL AS SNOW SHOWERS WITH THIS SYSTEM WITH SOME LIGHT SNOW
ACCUMULATION POSSIBLE FOR THE HIGHER TERRAIN. LOW TEMPERATURES
SHOULD BE A FEW DEGREES WARMER THEN TONIGHT GIVEN THE EXPECTED
CLOUD COVER. A MOSTLY SUNNY AND COLD START FOR THE NEW YEAR AS
ARCTIC HIGH PRESSURE NOSES SOUTHEASTWARD INTO THE REGION.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THE MAIN WEATHER CONCERNS DURING THIS PERIOD WILL BE THE
COMBINATION OF SNOW AND VERY COLD TEMPERATURES THURSDAY AND
FRIDAY. A STRONG NORTHERN STREAM SHORT WAVE TROUGH WILL MOVE
EASTWARD FROM THE MIDWEST TO THE GREAT LAKES WEDNESDAY NIGHT AND
THURSDAY. MOISTURE STREAMING EASTWARD WELL IN ADVANCE OF THE
POSITIVELY TILTED TROUGH AXIS WILL MOVE INTO OUR REGION LATE WED
NIGHT AND EARLY ON THURSDAY. THIS COUPLED WITH A BROAD AREA OF
ISENTROPIC LIFT WILL AID IN LIGHT SNOW BREAKING OUT ACROSS
SOUTHERN ZONES LATER WED NIGHT OR EARLY THURS MORNING...WHICH
SHOULD THEN SPREAD NORTHWARD AS THE DAY PROGRESSES.
AT THIS TIME IT DOES NOT LOOK LIKE THE TROUGH WILL AMPLIFY FAST
ENOUGH AND LINK UP WITH A GOOD AMOUNT OF SOUTHERN STREAM MOISTURE
TO ALLOW FOR A SIGNIFICANT SNOWSTORM FOR OUR AREA. AT THIS TIME IT
LOOKS LIKE WE/LL BE DEALING WITH OCCASIONAL LIGHT SNOW THAT WILL
ADD UP OVER THE COURSE OF 24-36 HOURS OR SO. THE BEST FORCING FOR
ASCENT WILL BE ACROSS SOUTHERNMOST ZONES...SO WE EXPECT SOUTHERN
NH AND PERHAPS SOUTHERNMOST MAINE TO PICK UP THE MOST SNOW OUT OF
THIS...WHICH MAY ADD UP TO 5 TO 10 INCHES OVER THAT RELATIVELY
LONG DURATION. SNOWFALL AMOUNTS WILL TAPER OFF RATHER QUICKLY AS
ONE HEADS FURTHER NORTH...WITH THE WESTERN ME MOUNTAINS AND
ADJACENT NORTHERNMOST NH LIKELY NOT PICKING UP MUCH IN THE WAY OF
ACCUMS. IN FACT...IT/S POSSIBLE THAT LOCATIONS IN THE PITTSBURG NH
TO JACKMAN ME CORRIDOR DON/T SEE MORE THAN A FEW FLURRIES. THE
SYSTEM LOOKS TO MOVE AWAY LATE THURSDAY NIGHT OR EARLY
FRIDAY...AND THIS WILL END THE THREAT OF SNOW FROM WEST TO EAST THEN.
THE MAIN ISSUE FOR THURS AND FRI WILL BE THE COLD TEMPERATURES AND
WIND CHILL VALUES. HIGHS THURS WILL RANGE FROM THE SINGLE NUMBERS
BELOW ZERO IN THE MOUNTAINS...TO SINGLE DIGITS ABOVE ZERO CLOSER TO
THE COAST. THE WARMEST READINGS WILL BE IN SOUTHERN NH WHERE HIGHS
MAY TOP OUT IN THE MID TEENS. STRONG HIGH PRESSURE WILL BE
SITUATED ACROSS SOUTHERN QUEBEC THURSDAY...AND THIS COUPLED WITH
THE LOW PRESSURE SYSTEM PASSING TO OUR SOUTH WILL RESULT IN A
TIGHTENING PRESSURE GRADIENT. WINDS SHOULD INCREASE AS THURS
PROGRESSES...WITH MOST MOMENTUM TRANSFER TOOLS YIELDING GUSTS
20-30 MPH THURS AFTERNOON AND NIGHT. THEREFORE...WE ARE LOOKING AT
VERY LOW WIND CHILL VALUES THURS THROUGH FRIDAY...WHICH MAY DROP
TO DANGEROUS LEVELS AT TIMES. WOULD NOT BE SURPRISED IF FORECAST
TEMPS THURS AFTN WILL HAVE TO BE DROPPED A COUPLE OF DEGREES
FURTHER BASED ON THE STRENGTH OF THE HIGH TO THE NORTH. SO IN A
NUTSHELL...REALLY COLD STUFF THURS AND FRI.
THEREAFTER...MODEL SOLUTIONS DIFFER WILDLY FOR EARLY NEXT
WEEK...WITH THE 00Z ECMWF STILL BRINGING AN INTENSE LOW PRESSURE
SYSTEM NORTHWARD THROUGH UPSTATE NY AND INTO QUEBEC MONDAY. THIS
SOLUTION IS AN OUTLIER AT THIS POINT...BUT THERE/S SOME
CONSISTENCY THERE...SO WE/LL HAVE TO CONTINUE TO MONITOR.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
SHORT TERM...VFR CONDITIONS EXPECTED TO PREVAIL INTO WED. A WEAK
LOW CROSSING THE AREA THIS AFTERNOON AND EVENING MAY BRING AREAS
OF MVFR OR LOWER CONDITIONS...ESPECIALLY ACROSS THE N/MT AREAS AND
OVER WRN NH...IMPACTING HIE AND LEB TAF SITES.
LONG TERM...FLIGHT RESTRICTIONS EXPECTED THU INTO FRI IN SNOW AND
BLOWING SNOW...WITH THE BETTER FOR LOWER RESTRICTIONS ALONG THE
COAST.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH WEDNESDAY/...WILL ALLOW SCA TO EXPIRE
WITH NEW MARINE PACKAGE AT 3 AM. WINDS AND SEAS WILL REMAIN BELOW
SCA UNTIL WEDNESDAY MORNING...WHEN I EXPECT THEY`LL INCREASE
QUICKLY TO SCA THRESHOLD FOLLOWING PASSAGE OF ARCTIC COLD FRONT.
LONG TERM...GALES POSSIBLE...IF NOT LIKELY...ON THE WATERS LATE
THURS AND FRI AS LOW PRESSURE PASSING TO THE SOUTH OF NEW ENGLAND
COUPLES WITH STRONG HIGH PRESSURE OVER QUEBEC. FREEZING SPRAY WILL
BE LIKELY AS WELL AS VERY COLD TEMPERATURES ADVECT OVER THE WATERS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EST
WEDNESDAY FOR ANZ150>152-154.
&&
$$
SYNOPSIS...
NEAR TERM...CEMPA
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
707 AM EST TUE DEC 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EST TUE DEC 31 2013
WV IMAGERY AND RUC ANALYSIS INDICATED CYCLONIC WNW MID/UPPER LEVEL
FLOW INTO THE NRN GREAT LAKES AROUND THE POLAR VORTEX LOCATED OVER
SRN HUDSON BAY. A SHORTWAVE TROUGH EXTENDING FROM LAKE SUPERIOR TO
INDIANA WAS SLIDING QUICKLY TO THE EAST AS A SFC RIDGE OR ARCTIC
HIGH PRES BUILDS FROM SASK AND THE NRN PLAINS INTO THE UPPER MS
VALLEY. VEERING LOW LEVEL WINDS TO WNW AND VERY COLD AIR WITH 850 MB
TEMPS FROM -21C TO -25C SUPPORTED LES BANDS INTO THE KEWEENAW AND
THE NE CWA. KMQT AND MONTREAL RIVER RADARS INDICATED THAT THE
HEAVIEST LES ASOCIATED WITH A TROUGH OR WEAK MESO LOW OVER SE LAKE
SUPERIOR HAD SHIFTED INTO NW LUCE COUNTY. SATELLITE AND WEB CAMS
OVER THE KEWEENAW SUGGEST THAT THE HEAVIER LES FROM MON AFTERNOON
AND EVENING HAD DIMINISHED AS LES TRANSITIONS TOWARD MULTIPLE WEAKER
BANDS. CLEARING OVER INLAND LOCATIONS HAS ALLOWED TEMPS TO DROP TO
AROUND -25F AT WAKEFIELD AND LANDOLAKES WHERE WINDS WERE CALM. WINDS
IN THE TO 10 MPH RANGE MOST LOCATIONS IN THE INTERIOR WEST COMBINED
WITH TEMPS IN THE -8 TO -15 RANGE HAS PUSHED WIND CHILLS INTO THE
-20 TO -30 RANGE.
TODAY...THE HIGH RES MODELS SUGGEST THAT THE STRONGEST LOW LEVEL
CONV SUPPORTED BY THE LAKE INDUCED TROUGHING OVER SE LAKE SUPERIOR
WILL GRADUALLY SHIFT TO THE EAST AS NW WINDS INCREASE ACROSS LAKE
SUPERIOR. WITH ENOUGH OF THE DGZ IN THE CONVECTIVE LAYER...SLR
VALUES SHOULD BE HIGH ENOUGH TO SUPPORT OVERALL SNOWFALL TOTALS IN
THE 4 TO 8 INCH RANGE...WITH SOME ISOLATED GREATER AMOUNTS POSSIBLE
WITH THE GREATEST AMOUNTS FROM GRAND MARAIS TO PINE STUMP JCT AND
CRISP POINT. OVER THE WEST...THE GREATEST LOW LEVEL CONV BETWEEN
HOUGHTON AND TWIN LAKES IS EXPECTED TO WEAKEN WITH NW FLOW ACROSS
THE SHORT AXIS OF THE WRN LAKE. ADDITIONAL AMOUNTS IN THE 1 TO 3
INCH RANGE ARE EXPECTED WITH THE GREATEST AMOUNTS THIS MORNING.
TONIGHT...AS THE ARCTIC RIDGE BUILDS INTO NRN ONTARIO...MODELS
SUGGEST THAT THE LOW LEVEL WINDS WILL CONTINUE TO VEER AND WEAKEN.
AS A RESULT THE LAKE INDUCED TROUGH OVER THE ERN LAKE AND BEST LOW
LEVEL CONV IS EXPECTED TO SHIFT BACK TO THE WEST. HOWEVER...THE
LOCATION OF ANY HEAVIER SNOWBANDS IS LESS CERTAIN. SO...2 TO 5 INCH
AMOUNTS MAY BE POSSIBLE BETWEEN MUUNSING AND NRN LUCE COUNTY. WITH
MORE ACYC FLOW OVER THE WEST AND INVERSION HEIGHTS DROPPING TO
AROUND 4K FT...MAINLY 1 TO 2 INCH AMOUNTS ARE EXPECTED. EVEN THOUGH
TEMPS WILL DROP OFF AGAIN TO -15 TO -20 OVER THE INLAND WEST...LIGHTER
WINDS AT OR BELOW 5 MPH SHOULD REDUCE THE SEVERITY OF WIND
CHILLS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 539 AM EST TUE DEC 31 2013
WILL START OFF WEDNESDAY MORNING WHERE WE ARE ALL TOO FAMILIAR
WITH...UNDER A BROAD 500MB TROUGH. THE CENTER OF THE LOW WILL BE
OVER CENTRAL QUEBEC...WITH A TROUGH EXTENDING SE ACROSS THE N PLAINS
AND INTO THE 4-CORNERS REGION. A DISTURBANCE TRACKING TO OUR S LOOKS
TO BE TOO FAR AWAY TO DO MUCH FOR OUR WX UP N...SO GOT RID OF THE
SLIGHT CHANCE POPS THAT WERE BLANKETING S CENTRAL UPPER MI WEDNESDAY.
THE COLD SNAP WILL LINGER THROUGH THURSDAY...BEFORE SLOWLY
MODERATING FRIDAY AND SATURDAY. WILL WILL CONTINUE TO BE IN A
DIFFICULT POSITION...WHERE TEMPERATURES WILL BE VERY COLD...BUT
WINDS WILL BE BORDERLINE OR WELL BELOW WIND CHILL ADVISORY CRITERIA
/10MPH/.
MUCH OF OUR WX IN THE MID RANGE OF THE FCST PERIOD WILL BE DOMINATED
BY THE WEAKENING BY STILL PERSISTENT SFC LOW/TROUGH WEAKENING ACROSS
E LAKE SUPERIOR AND E UPPER MI. WHILE THE STRONG HIGH OVER MN IS
ABLE TO TO DISRUPT THE LES OVER FAR W UPPER MI WEDNESDAY AND
WEDNESDAY NIGHT...PERSISTENT N TO NW FLOW SHOULD KEEP A HEALTHY BAND
OR MORE LIKELY MULTI-BAND LES GOING E OF MARQUETTE THROUGH
MUNISING...AND E OF MUNISING NEAR LAKE SUPERIOR.
FOR LATE THURSDAY AFTERNOON THROUGH THURSDAY NIGHT...THE EVER
WEAKENING SFC TROUGH OUT E WILL FINALLY LOSE OUT...WITH THE 500MB
TROUGH EXITING E TO THE LOWER GREAT LAKES. LIGHT AND MORE VARIABLE
NEAR-SFC WINDS SHOULD PUSH LIGHT/MODERATE LES BANDS OFF INTO LAKE
SUPERIOR.
CONTINUED AN ATTEMPT TO ADD SOME BETTER TIMING TO THE LONGER TERM
POPS/WX FOR FRIDAY ON. MODELS ARE CONSISTENT ON BRINGING THE 500MB
RIDGE ACROSS THE UPPER GREAT LAKES FRIDAY...WITH THE NEXT LOW OVER
CENTRAL CANADA POISED TO SINK SE AND DOMINATE OUR WX FOR THROUGH AT
LEAST EARLY NEXT WEEK.
BROUGHT THE STRONG SW WINDS MORE TO THE GREAT LAKES SHORELINES
FRIDAY/SATURDAY...AS THE LARGER SCALE MODELS TYPICALLY HAVE A
DIFFICULT TIME WITH THIS. GALES WILL BE POSSIBLE OVER LAKE MI...AND
E LAKE SUPERIOR LATE FRIDAY AFTERNOON THROUGH EARLY SATURDAY
MORNING. BLOWING SNOW WAS ALSO INTRODUCED...MAINLY CENTRAL AND E
NEAR THE GREAT LAKES. 45-55KT WINDS AT 850MB ARE STILL BEING SHOWN
18Z FRIDAY TO AROUND 12Z SATURDAY. MODEL DISCREPANCIES REMAIN IN THE
TIMING OF THE SFC LOW AND ITS ASSOCIATED COLD FRONT...ALTHOUGH MUCH
MORE IN LINE THAN 24HRS AGO. EXPECT THE
A BURST OF HEAVY WET SNOW WILL BE POSSIBLE ACROSS MUCH OF THE CWA IF
THE GFS IS CORRECT. WILL GO CLOSER TO THE 31/00Z ECMWF AT THIS POINT
WITH THE BULK OF THE ENERGY SLIDING ACROSS THE N HALF OF THE
AREA...WITH LES COMING BACK IN BEHIND THE PASSAGE OF THE COLD FRONT
SATURDAY MORNING. WITH THE COLD AIR RAPIDLY SWINGING BACK IN ON W TO
NW WINDS SATURDAY AFTERNOON INTO EARLY SUNDAY...EXPECT A BRIEF
MOMENT OF LAKE ENHANCED SNOW ACROSS THE KEWEENAW PENINSULA.
HIGHLIGHTED THE POTENTIAL IN THE HWO/EHWO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 654 AM EST TUE DEC 31 2013
KIWD...AS WINDS VEER FROMM SW TO WNW IN THE WAKE OF A DISTURBANCE
PASSING TO THE SOUTH OF UPPER MI...EXPECT SOME LAKE EFFECT CLOUDS
AND LIGHT SNOW SHOWERS TO MOVE BACK IN THIS MORNING. CONDITIONS
SHOULD GRADUALLY DROP FROM VFR TO MVFR. IFR VSBYS ARE POSSIBLE LATER
IN THE DAY IF THE FLOW VEERS FAR ENOUGH TO THE NW.
KCMX...VEERING W TO NW FLOW OF ARCTIC AIR WILL KEEP LES GOING
DURING THE FORECAST PERIOD. ALTHOUGH THERE COULD BE SOME IMPROVEMENT
IN VSBY BETWEEN THE LES BANDS...IFR CONDITIONS SHOULD PREDOMINATE.
SAW...WITH A DOWNSLOPE WSW FLOW OF DRY ARCTIC AIR VEERING TO WNW...
EXPECT VFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD EVEN THOUGH
OCNL FLURRIES/MVFR CIGS WL BE POSSIBLE THIS AFTN/EVNG.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 349 AM EST TUE DEC 31 2013
HEAVY FREEZING SPRAY WILL REMAIN A CONCERN FOR MAINLY CENTRAL AND
EASTERN LAKE SUPERIOR THROUGH EARLY WEDESDAY...AS AIR TEMPS CONTINUE TO
BE IN THE TEENS ABOVE ZERO TO THE SINGLE DIGITS BELOW ZERO...AND NW
TO N WINDS IN THE 20-30KT RANGE.
STRONG HIGH PRESSURE OVER SASKATCHEWAN WILL BUILD INTO MINNESOTA
TONIGHT...AND REMAIN NEARLY STATIONARY THROUGH THURSDAY.
OTHERWISE...THE PESKY LOW/TROUGH STRETCHING FROM EASTERN LAKE
SUPERIOR TO ALL OF SOUTHEASTERN ONTARIO WILL EXIT EASTWARD
TODAY...LEAVING A WEAKENING TROUGH ACROSS LAKE SUPERIOR THAT WILL
LINGER THROUGH THURSDAY...AS THE HIGH PRESSURE SYSTEM TO OUR WEST
SINKS INTO THE MID MISSISSIPPI VALLEY. EXPECT LOW PRESSURE ALONG THE
CENTRAL U.S./CANADIAN BORDER FRIDAY TO CROSS LAKE SUPERIOR AND
ONTARIO ON SATURDAY. AHEAD OF THIS LOW...S GUSTS OF 25-30KTS LATE
FRIDAY AFTERNOON INTO SATURDAY MORNING MAY JUMP UP TO GALES
/PARTICULARLY ACROSS E LAKE SUPERIOR FRIDAY NIGHT/.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR
MIZ002-004-005-009>013-084.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-085.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR MIZ003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST
WEDNESDAY FOR LSZ267.
HEAVY FREEZING SPRAY WARNING UNTIL 9 AM EST WEDNESDAY FOR LSZ243-
244-264-266.
HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST WEDNESDAY FOR LSZ248-
265.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
WEDNESDAY FOR LSZ241-242-263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ249-
250.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
541 AM EST TUE DEC 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EST TUE DEC 31 2013
WV IMAGERY AND RUC ANALYSIS INDICATED CYCLONIC WNW MID/UPPER LEVEL
FLOW INTO THE NRN GREAT LAKES AROUND THE POLAR VORTEX LOCATED OVER
SRN HUDSON BAY. A SHORTWAVE TROUGH EXTENDING FROM LAKE SUPERIOR TO
INDIANA WAS SLIDING QUICKLY TO THE EAST AS A SFC RIDGE OR ARCTIC
HIGH PRES BUILDS FROM SASK AND THE NRN PLAINS INTO THE UPPER MS
VALLEY. VEERING LOW LEVEL WINDS TO WNW AND VERY COLD AIR WITH 850 MB
TEMPS FROM -21C TO -25C SUPPORTED LES BANDS INTO THE KEWEENAW AND
THE NE CWA. KMQT AND MONTREAL RIVER RADARS INDICATED THAT THE
HEAVIEST LES ASOCIATED WITH A TROUGH OR WEAK MESO LOW OVER SE LAKE
SUPERIOR HAD SHIFTED INTO NW LUCE COUNTY. SATELLITE AND WEB CAMS
OVER THE KEWEENAW SUGGEST THAT THE HEAVIER LES FROM MON AFTERNOON
AND EVENING HAD DIMINISHED AS LES TRANSITIONS TOWARD MULTIPLE WEAKER
BANDS. CLEARING OVER INLAND LOCATIONS HAS ALLOWED TEMPS TO DROP TO
AROUND -25F AT WAKEFIELD AND LANDOLAKES WHERE WINDS WERE CALM. WINDS
IN THE TO 10 MPH RANGE MOST LOCATIONS IN THE INTERIOR WEST COMBINED
WITH TEMPS IN THE -8 TO -15 RANGE HAS PUSHED WIND CHILLS INTO THE
-20 TO -30 RANGE.
TODAY...THE HIGH RES MODELS SUGGEST THAT THE STRONGEST LOW LEVEL
CONV SUPPORTED BY THE LAKE INDUCED TROUGHING OVER SE LAKE SUPERIOR
WILL GRADUALLY SHIFT TO THE EAST AS NW WINDS INCREASE ACROSS LAKE
SUPERIOR. WITH ENOUGH OF THE DGZ IN THE CONVECTIVE LAYER...SLR
VALUES SHOULD BE HIGH ENOUGH TO SUPPORT OVERALL SNOWFALL TOTALS IN
THE 4 TO 8 INCH RANGE...WITH SOME ISOLATED GREATER AMOUNTS POSSIBLE
WITH THE GREATEST AMOUNTS FROM GRAND MARAIS TO PINE STUMP JCT AND
CRISP POINT. OVER THE WEST...THE GREATEST LOW LEVEL CONV BETWEEN
HOUGHTON AND TWIN LAKES IS EXPECTED TO WEAKEN WITH NW FLOW ACROSS
THE SHORT AXIS OF THE WRN LAKE. ADDITIONAL AMOUNTS IN THE 1 TO 3
INCH RANGE ARE EXPECTED WITH THE GREATEST AMOUNTS THIS MORNING.
TONIGHT...AS THE ARCTIC RIDGE BUILDS INTO NRN ONTARIO...MODELS
SUGGEST THAT THE LOW LEVEL WINDS WILL CONTINUE TO VEER AND WEAKEN.
AS A RESULT THE LAKE INDUCED TROUGH OVER THE ERN LAKE AND BEST LOW
LEVEL CONV IS EXPECTED TO SHIFT BACK TO THE WEST. HOWEVER...THE
LOCATION OF ANY HEAVIER SNOWBANDS IS LESS CERTAIN. SO...2 TO 5 INCH
AMOUNTS MAY BE POSSIBLE BETWEEN MUUNSING AND NRN LUCE COUNTY. WITH
MORE ACYC FLOW OVER THE WEST AND INVERSION HEIGHTS DROPPING TO
AROUND 4K FT...MAINLY 1 TO 2 INCH AMOUNTS ARE EXPECTED. EVEN THOUGH
TEMPS WILL DROP OFF AGAIN TO -15 TO -20 OVER THE INLAND WEST...LIGHTER
WINDS AT OR BELOW 5 MPH SHOULD REDUCE THE SEVERITY OF WIND
CHILLS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 539 AM EST TUE DEC 31 2013
WILL START OFF WEDNESDAY MORNING WHERE WE ARE ALL TOO FAMILIAR
WITH...UNDER A BROAD 500MB TROUGH. THE CENTER OF THE LOW WILL BE
OVER CENTRAL QUEBEC...WITH A TROUGH EXTENDING SE ACROSS THE N PLAINS
AND INTO THE 4-CORNERS REGION. A DISTURBANCE TRACKING TO OUR S LOOKS
TO BE TOO FAR AWAY TO DO MUCH FOR OUR WX UP N...SO GOT RID OF THE
SLIGHT CHANCE POPS THAT WERE BLANKETING S CENTRAL UPPER MI WEDNESDAY.
THE COLD SNAP WILL LINGER THROUGH THURSDAY...BEFORE SLOWLY
MODERATING FRIDAY AND SATURDAY. WILL WILL CONTINUE TO BE IN A
DIFFICULT POSITION...WHERE TEMPERATURES WILL BE VERY COLD...BUT
WINDS WILL BE BORDERLINE OR WELL BELOW WIND CHILL ADVISORY CRITERIA
/10MPH/.
MUCH OF OUR WX IN THE MID RANGE OF THE FCST PERIOD WILL BE DOMINATED
BY THE WEAKENING BY STILL PERSISTENT SFC LOW/TROUGH WEAKENING ACROSS
E LAKE SUPERIOR AND E UPPER MI. WHILE THE STRONG HIGH OVER MN IS
ABLE TO TO DISRUPT THE LES OVER FAR W UPPER MI WEDNESDAY AND
WEDNESDAY NIGHT...PERSISTENT N TO NW FLOW SHOULD KEEP A HEALTHY BAND
OR MORE LIKELY MULTI-BAND LES GOING E OF MARQUETTE THROUGH
MUNISING...AND E OF MUNISING NEAR LAKE SUPERIOR.
FOR LATE THURSDAY AFTERNOON THROUGH THURSDAY NIGHT...THE EVER
WEAKENING SFC TROUGH OUT E WILL FINALLY LOSE OUT...WITH THE 500MB
TROUGH EXITING E TO THE LOWER GREAT LAKES. LIGHT AND MORE VARIABLE
NEAR-SFC WINDS SHOULD PUSH LIGHT/MODERATE LES BANDS OFF INTO LAKE
SUPERIOR.
CONTINUED AN ATTEMPT TO ADD SOME BETTER TIMING TO THE LONGER TERM
POPS/WX FOR FRIDAY ON. MODELS ARE CONSISTENT ON BRINGING THE 500MB
RIDGE ACROSS THE UPPER GREAT LAKES FRIDAY...WITH THE NEXT LOW OVER
CENTRAL CANADA POISED TO SINK SE AND DOMINATE OUR WX FOR THROUGH AT
LEAST EARLY NEXT WEEK.
BROUGHT THE STRONG SW WINDS MORE TO THE GREAT LAKES SHORELINES
FRIDAY/SATURDAY...AS THE LARGER SCALE MODELS TYPICALLY HAVE A
DIFFICULT TIME WITH THIS. GALES WILL BE POSSIBLE OVER LAKE MI...AND
E LAKE SUPERIOR LATE FRIDAY AFTERNOON THROUGH EARLY SATURDAY
MORNING. BLOWING SNOW WAS ALSO INTRODUCED...MAINLY CENTRAL AND E
NEAR THE GREAT LAKES. 45-55KT WINDS AT 850MB ARE STILL BEING SHOWN
18Z FRIDAY TO AROUND 12Z SATURDAY. MODEL DISCREPANCIES REMAIN IN THE
TIMING OF THE SFC LOW AND ITS ASSOCIATED COLD FRONT...ALTHOUGH MUCH
MORE IN LINE THAN 24HRS AGO. EXPECT THE
A BURST OF HEAVY WET SNOW WILL BE POSSIBLE ACROSS MUCH OF THE CWA IF
THE GFS IS CORRECT. WILL GO CLOSER TO THE 31/00Z ECMWF AT THIS POINT
WITH THE BULK OF THE ENERGY SLIDING ACROSS THE N HALF OF THE
AREA...WITH LES COMING BACK IN BEHIND THE PASSAGE OF THE COLD FRONT
SATURDAY MORNING. WITH THE COLD AIR RAPIDLY SWINGING BACK IN ON W TO
NW WINDS SATURDAY AFTERNOON INTO EARLY SUNDAY...EXPECT A BRIEF
MOMENT OF LAKE ENHANCED SNOW ACROSS THE KEWEENAW PENINSULA.
HIGHLIGHTED THE POTENTIAL IN THE HWO/EHWO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1223 AM EST TUE DEC 31 2013
KIWD...AS WINDS VEER FM SW TO WNW IN THE WAKE OF A DISTURBANCE
PASSING TO THE S OF UPR MI...EXPECT SOME LK EFFECT CLDS/-SHSN TO
SPREAD BACK OVER THIS SITE BY SUNRISE. CONDITIONS SHOULD GRDLY
DETERIORATE FM VFR TO MVFR. IFR VSBYS ARE PSBL LATER IN THE DAY IF
THE FLOW VEERS FAR ENUF TO THE NW.
KCMX...VEERING W TO NW FLOW OF ARCTIC AIR WL ALLOW LK EFFECT -SHSN
TO IMPACT THIS LOCATION THIS FCST PERIOD. ALTHOUGH THERE COULD BE
SOME IMPROVEMENT IN VSBYS BTWN THE BANDS...IFR CONDITIONS SHOULD
PREDOMINATE.
SAW...WITH A DOWNSLOPE WSW FLOW OF DRY ARCTIC AIR VEERING TO WNW...
EXPECT VFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD EVEN THOUGH
OCNL FLURRIES/MVFR CIGS WL BE POSSIBLE THIS AFTN/EVNG.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 349 AM EST TUE DEC 31 2013
HEAVY FREEZING SPRAY WILL REMAIN A CONCERN FOR MAINLY CENTRAL AND
EASTERN LAKE SUPERIOR THROUGH EARLY WEDESDAY...AS AIR TEMPS CONTINUE TO
BE IN THE TEENS ABOVE ZERO TO THE SINGLE DIGITS BELOW ZERO...AND NW
TO N WINDS IN THE 20-30KT RANGE.
STRONG HIGH PRESSURE OVER SASKATCHEWAN WILL BUILD INTO MINNESOTA
TONIGHT...AND REMAIN NEARLY STATIONARY THROUGH THURSDAY.
OTHERWISE...THE PESKY LOW/TROUGH STRETCHING FROM EASTERN LAKE
SUPERIOR TO ALL OF SOUTHEASTERN ONTARIO WILL EXIT EASTWARD
TODAY...LEAVING A WEAKENING TROUGH ACROSS LAKE SUPERIOR THAT WILL
LINGER THROUGH THURSDAY...AS THE HIGH PRESSURE SYSTEM TO OUR WEST
SINKS INTO THE MID MISSISSIPPI VALLEY. EXPECT LOW PRESSURE ALONG THE
CENTRAL U.S./CANADIAN BORDER FRIDAY TO CROSS LAKE SUPERIOR AND
ONTARIO ON SATURDAY. AHEAD OF THIS LOW...S GUSTS OF 25-30KTS LATE
FRIDAY AFTERNOON INTO SATURDAY MORNING MAY JUMP UP TO GALES
/PARTICULARLY ACROSS E LAKE SUPERIOR FRIDAY NIGHT/.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR
MIZ002-004-005-009>013-084.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-085.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR MIZ003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST
WEDNESDAY FOR LSZ267.
HEAVY FREEZING SPRAY WARNING UNTIL 9 AM EST WEDNESDAY FOR LSZ243-
244-264-266.
HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST WEDNESDAY FOR LSZ248-
265.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
WEDNESDAY FOR LSZ241-242-263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ249-
250.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...KC
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
519 AM EST TUE DEC 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EST TUE DEC 31 2013
WV IMAGERY AND RUC ANALYSIS INDICATED CYCLONIC WNW MID/UPPER LEVEL
FLOW INTO THE NRN GREAT LAKES AROUND THE POLAR VORTEX LOCATED OVER
SRN HUDSON BAY. A SHORTWAVE TROUGH EXTENDING FROM LAKE SUPERIOR TO
INDIANA WAS SLIDING QUICKLY TO THE EAST AS A SFC RIDGE OR ARCTIC
HIGH PRES BUILDS FROM SASK AND THE NRN PLAINS INTO THE UPPER MS
VALLEY. VEERING LOW LEVEL WINDS TO WNW AND VERY COLD AIR WITH 850 MB
TEMPS FROM -21C TO -25C SUPPORTED LES BANDS INTO THE KEWEENAW AND
THE NE CWA. KMQT AND MONTREAL RIVER RADARS INDICATED THAT THE
HEAVIEST LES ASOCIATED WITH A TROUGH OR WEAK MESO LOW OVER SE LAKE
SUPERIOR HAD SHIFTED INTO NW LUCE COUNTY. SATELLITE AND WEB CAMS
OVER THE KEWEENAW SUGGEST THAT THE HEAVIER LES FROM MON AFTERNOON
AND EVENING HAD DIMINISHED AS LES TRANSITIONS TOWARD MULTIPLE WEAKER
BANDS. CLEARING OVER INLAND LOCATIONS HAS ALLOWED TEMPS TO DROP TO
AROUND -25F AT WAKEFIELD AND LANDOLAKES WHERE WINDS WERE CALM. WINDS
IN THE TO 10 MPH RANGE MOST LOCATIONS IN THE INTERIOR WEST COMBINED
WITH TEMPS IN THE -8 TO -15 RANGE HAS PUSHED WIND CHILLS INTO THE
-20 TO -30 RANGE.
TODAY...THE HIGH RES MODELS SUGGEST THAT THE STRONGEST LOW LEVEL
CONV SUPPORTED BY THE LAKE INDUCED TROUGHING OVER SE LAKE SUPERIOR
WILL GRADUALLY SHIFT TO THE EAST AS NW WINDS INCREASE ACROSS LAKE
SUPERIOR. WITH ENOUGH OF THE DGZ IN THE CONVECTIVE LAYER...SLR
VALUES SHOULD BE HIGH ENOUGH TO SUPPORT OVERALL SNOWFALL TOTALS IN
THE 4 TO 8 INCH RANGE...WITH SOME ISOLATED GREATER AMOUNTS POSSIBLE
WITH THE GREATEST AMOUNTS FROM GRAND MARAIS TO PINE STUMP JCT AND
CRISP POINT. OVER THE WEST...THE GREATEST LOW LEVEL CONV BETWEEN
HOUGHTON AND TWIN LAKES IS EXPECTED TO WEAKEN WITH NW FLOW ACROSS
THE SHORT AXIS OF THE WRN LAKE. ADDITIONAL AMOUNTS IN THE 1 TO 3
INCH RANGE ARE EXPECTED WITH THE GREATEST AMOUNTS THIS MORNING.
TONIGHT...AS THE ARCTIC RIDGE BUILDS INTO NRN ONTARIO...MODELS
SUGGEST THAT THE LOW LEVEL WINDS WILL CONTINUE TO VEER AND WEAKEN.
AS A RESULT THE LAKE INDUCED TROUGH OVER THE ERN LAKE AND BEST LOW
LEVEL CONV IS EXPECTED TO SHIFT BACK TO THE WEST. HOWEVER...THE
LOCATION OF ANY HEAVIER SNOWBANDS IS LESS CERTAIN. SO...2 TO 5 INCH
AMOUNTS MAY BE POSSIBLE BETWEEN MUUNSING AND NRN LUCE COUNTY. WITH
MORE ACYC FLOW OVER THE WEST AND INVERSION HEIGHTS DROPPING TO
AROUND 4K FT...MAINLY 1 TO 2 INCH AMOUNTS ARE EXPECTED. EVEN THOUGH
TEMPS WILL DROP OFF AGAIN TO -15 TO -20 OVER THE INLAND WEST...LIGHTER
WINDS AT OR BELOW 5 MPH SHOULD REDUCE THE SEVERITY OF WIND
CHILLS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 430 PM EST MON DEC 30 2013
MODELS ARE CONSISTENT IN SHOWING THE 500MB CLOSED LOW OVER QUEBEC
WEDNESDAY MOVING OFF INTO THE ATLANTIC THURSDAY. THE GFS /AS USUAL/
IS MORE PROGRESSIVE THAN THE ECWMF WITH THE LONGWAVE TROUGH IN THE
WAKE OF THE LOW...BRINGING THE TROUGH THROUGH THE GREAT LAKES ON
THURSDAY AFTERNOON. THE ECMWF IS SLOWER AND DEEPER WITH THIS
TROUGH...WITH IT BEING MAINLY OVER WI ON THURSDAY AFTERNOON.
GUIDANCE SUGGESTS THAT THE ECMWF HAS BEEN ERRING ON THE DEEPER AND
MORE AMPLIFIED SIDE LATELY...HOWEVER...AND THIS MAY BE THE CASE.
OVERALL WENT MIDDLE OF THE ROAD FOR THE FORECAST AT THIS
POINT...LEANING MORE TOWARDS THE ECMWF. AS FAR AS WHAT THIS MEANS
FOR THE SURFACE...LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS AND
RIDES NORTHEASTWARD ALONG THE TROUGH...WHICH BRINGS AN INVERTED
SURFACE TROUGH INTO UPPER MI FOR WEDNESDAY NIGHT-THURSDAY AFTERNOON.
TUESDAY NIGHT WINDS REMAIN OUT OF THE WEST NORTHWEST THROUGH
MIDNIGHT...BEFORE GRADUALLY VEERING TO THE NORTH AND EVEN NORTHEAST
AS THE INVERTED TROUGH SHIFTS WESTWARD. THIS MOVES THE HIGHEST POPS
FROM THE FAR NORTHEASTERN PORTIONS OF THE COUNTY TOWARDS MUNISING
THROUGH THE NIGHT. BY WEDNESDAY AFTERNOON...CONVERGENCE FOCUSES
BETWEEN MARQUETTE AND MUNISING...WHICH IS WHERE HIGHEST POPS ARE
SITUATED IN THE GRIDS. WHILE THIS REMAINS THE CASE THROUGH THURSDAY
AFTERNOON...TOTAL ACCUMULATIONS ARE GENERALLY EXPECTED TO BE ON THE
ORDER OF 2 TO 4 INCHES BETWEEN SHOT POINT AND MUNISING. GIVEN THAT
MOST OF THE BANDS ARE SHIFTING FROM WEST-NORTHWEST INTO A MORE
NORTH-NORTHEAST PATTERN THROUGH THE PERIOD...NOT REALLY EXPECTING
ANY ONE LOCATION TO RECEIVE TOO MUCH ACCUMULATION. ALSO...BEYOND
WEDNESDAY MORNING...WINDS AT 850-925MB BECOME SOMEWHAT MISALIGNED
WITH THE SURFACE WINDS...WHICH IS TYPICALLY LESS SUITABLE FOR MORE
STRUCTURED BANDS. THOUGH INVERSION HEIGHTS ARE HIGHER WITH COLDER
850MB TEMPS...GENERALLY UP TO 6-8KFT...THE DGZ IS LOW AND SO EXPECT
THE SAME SMALL SIZED FLAKES-AND LOW ACCUMULATIONS LIKE THOSE
OBSERVED ACROSS UPPER MI ALL WEEK/DESPITE SIMILAR INVERSION HEIGHTS.
THE NAM HINTS AT SOME HIGHER SNOW RATIOS OCCURRING IN THE
EAST...HOWEVER...THE NAM HAS BEEN TRENDING HIGHER THROUGH THIS PAST
WEEK THAN WHAT IS BEING OBSERVED. OVERALL...WEVE SEEN AROUND 18-20:1
RATIOS...AND THIS IS WHAT WAS USED FOR THE FORECAST. USING THE
NAM...THE BEST LIFT COLLOCATED WITH THE DGZ IS BETWEEN 6Z AND 15Z
WEDNESDAY AROUND MUNISING...AND SOME BIGGER FLAKES MAY BE SEEN
DURING THIS TIME. OTHERWISE...EXPECT ACCUMULATIONS TO RANGE FROM 1-3
INCHES NEAR THE LAKE FROM 6Z WEDNESDAY TO 12Z THURSDAY.
FRIDAY INTO SATURDAY LOW PRESSURE SLIDING OVER THE CANADIAN PRAIRIE
WILL SWING WINDS AROUND TO THE SOUTH ACROSS UPPER MI...PUSHING ALL
LAKE EFFECT SNOW BANDS OFF INTO LAKE SUPERIOR. 850MB TEMPS WARM AS
WELL...WITH THE ECMWF HINTING AT -8C TO -10C FOR BOTH DAYS. THE COLD
FRONT PASSES ON SATURDAY NIGHT. THE ARCTIC PUSH BEHIND THIS TROUGH
IS NOT TOO BAD...AS TEMPS 850MB TEMPS ARE SOMEWHAT RESCUED BY A
BRIEF RIDGE MOVING FROM THE NORTHERN PLAINS INTO THE GREAT LAKES
THROUGH SUNDAY AFTERNOON. KEPT BROAD CHANCE POPS ACROSS THE CWA FOR
MUCH OF THE FORECAST AREA THROUGH SATURDAY NIGHT. ON SUNDAY...TEMPS
ARE COLD ENOUGH AND WINDS OUT OF THE WEST-NORTHWEST...SO KEPT CHANCE
POPS CONFINED TO LAKE SUPERIOR.
THE MAIN DIFFERENCES BETWEEN MODELS LIE ON MONDAY...WITH THE ECMWF
AND THE GFS BOTH HINTING AT A VERY COLD ARCTIC PUSH OF AIR SLIDING
THROUGH...WITH 850MB TEMPS AS LOW AS -35C OVER UPPER MI. THOUGH THE
GFS IS NOT QUITE AS LOW...IT HAS 850MB TEMPS AT -25C TO -30C FOR THE
AREA. WILL TREND LOWER WITH TEMPS DURING THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1223 AM EST TUE DEC 31 2013
KIWD...AS WINDS VEER FM SW TO WNW IN THE WAKE OF A DISTURBANCE
PASSING TO THE S OF UPR MI...EXPECT SOME LK EFFECT CLDS/-SHSN TO
SPREAD BACK OVER THIS SITE BY SUNRISE. CONDITIONS SHOULD GRDLY
DETERIORATE FM VFR TO MVFR. IFR VSBYS ARE PSBL LATER IN THE DAY IF
THE FLOW VEERS FAR ENUF TO THE NW.
KCMX...VEERING W TO NW FLOW OF ARCTIC AIR WL ALLOW LK EFFECT -SHSN
TO IMPACT THIS LOCATION THIS FCST PERIOD. ALTHOUGH THERE COULD BE
SOME IMPROVEMENT IN VSBYS BTWN THE BANDS...IFR CONDITIONS SHOULD
PREDOMINATE.
SAW...WITH A DOWNSLOPE WSW FLOW OF DRY ARCTIC AIR VEERING TO WNW...
EXPECT VFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD EVEN THOUGH
OCNL FLURRIES/MVFR CIGS WL BE POSSIBLE THIS AFTN/EVNG.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 349 AM EST TUE DEC 31 2013
HEAVY FREEZING SPRAY WILL REMAIN A CONCERN FOR MAINLY CENTRAL AND
EASTERN LAKE SUPERIOR THROUGH EARLY WEDESDAY...AS AIR TEMPS CONTINUE TO
BE IN THE TEENS ABOVE ZERO TO THE SINGLE DIGITS BELOW ZERO...AND NW
TO N WINDS IN THE 20-30KT RANGE.
STRONG HIGH PRESSURE OVER SASKATCHEWAN WILL BUILD INTO MINNESOTA
TONIGHT...AND REMAIN NEARLY STATIONARY THROUGH THURSDAY.
OTHERWISE...THE PESKY LOW/TROUGH STRETCHING FROM EASTERN LAKE
SUPERIOR TO ALL OF SOUTHEASTERN ONTARIO WILL EXIT EASTWARD
TODAY...LEAVING A WEAKENING TROUGH ACROSS LAKE SUPERIOR THAT WILL
LINGER THROUGH THURSDAY...AS THE HIGH PRESSURE SYSTEM TO OUR WEST
SINKS INTO THE MID MISSISSIPPI VALLEY. EXPECT LOW PRESSURE ALONG THE
CENTRAL U.S./CANADIAN BORDER FRIDAY TO CROSS LAKE SUPERIOR AND
ONTARIO ON SATURDAY. AHEAD OF THIS LOW...S GUSTS OF 25-30KTS LATE
FRIDAY AFTERNOON INTO SATURDAY MORNING MAY JUMP UP TO GALES
/PARTICULARLY ACROSS E LAKE SUPERIOR FRIDAY NIGHT/.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR
MIZ002-004-005-009>013-084.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-085.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR MIZ003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST
WEDNESDAY FOR LSZ267.
HEAVY FREEZING SPRAY WARNING UNTIL 9 AM EST WEDNESDAY FOR LSZ243-
244-264-266.
HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST WEDNESDAY FOR LSZ248-
265.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
WEDNESDAY FOR LSZ241-242-263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ249-
250.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MCD
AVIATION...KC
MARINE...KF
AREA FORECAST DISCUSSION
NWS BILLINGS MT
317 AM MST TUE DEC 31 2013
.SHORT TERM...VALID FOR TDY AND WED...
ACTIVE WEATHER COMING IN THE SHORT TERM WITH BOTH WIND AND SNOW
CONCERNS.
FIRST WIND. LIVINGSTON HAS BEEN HITTING ADVISORY GUSTS FOR SEVERAL
HOURS AND WILL MAKE NO CHANGE TO THE HIGHLIGHT IN PLACE. LEE SIDE
PRESSURE RISES ARE BEGINNING TO REDUCE THE GRADIENT SLOWLY...BUT
WOULD EXPECT HIGH GUSTS TO CONTINUE FOR MUCH OF THE DAY AS SFC
TROF REMAINS IN CENTRAL MT. COULD SEE GUSTS AS HIGH AS 50 MPH AT
BIG TIMBER AND THE BEARTOOTH FOOTHILLS BUT ORIENTATION OF GRADIENT
SHOULD FAVOR LVM MOST TODAY. COLD ADVECTION FROM THE NW SHOULD END
THE HIGHER GAP FLOW GUSTS BY THIS EVENING.
NOW SNOW. SHORTWAVE EMBEDDED IN NW FLOW ALOFT PUSHING INTO
EASTERN MT IS PRODUCING SOME SNOW ACROSS OUR EAST. MOST
INTERESTING FEATURE IS HEAVIER BAND DROPPING INTO NORTHERN
ROSEBUD AND CUSTER COUNTIES AT 10Z...WHICH IS IN REGION OF STRONG
850MB FRONTOGENESIS. EXPECT A BURST OF FAIRLY HEAVY SNOW OVER THE
NEXT FEW HOURS FROM MILES CITY TO BAKER AND EKALAKA...WITH 1 TO 2
INCHES LIKELY BEFORE THE PCPN DIMINISHES BY AROUND SUNRISE.
FURTHER WEST...STRONG DOWNSLOPE WINDS WILL KEEP LOCATIONS FROM
BILLINGS WEST DRY THIS MORNING. CURRENT TEMPERATURE GRADIENT
ACROSS OUR CWA IS IMPRESSIVE WITH BALMY TEMPS AROUND 40F TO OUR
WEST AND ONLY THE LOW TEENS IN OUR EAST.
STRONGER SHORTWAVE ALONG THE NORTHWEST BC COAST WILL PUSH TOWARD
OUR REGION LATER TODAY...WITH FAIRLY STRONG Q-VECTOR CONVERGENCE
EXPECTED TO BEGIN AROUND 00Z. INTERACTION WITH LOW LEVEL SFC
FRONT IS CRITICAL FOR THE PCPN FORECAST FOR TONIGHT. GFS/ECMWF ARE
CONSISTENT IN BRINGING THIS BOUNDARY AS FAR WEST AS BILLINGS AND
SHERIDAN BY 00Z...WHEREAS THE NAM AND RAP ARE SLOWER. UPSTREAM...
NOTE THAT CUT BANK HAS SHIFTED TO THE NE OVER THE PAST COUPLE
HOURS IN RESPONSE TO SLIGHT PRESSURE RISES BUILDING INTO NORTH
CENTRAL MT. GIVEN THIS IN ADDITION TO EAST WINDS AROUND 20 MPH AT
MLS AND BHK ARE STRONGER THAN ANY GUIDANCE SUGGESTS...BELIEVE THE
GFS/EC ARE CORRECT WITH THE FASTER SOUTHWESTWARD EVOLUTION OF
THIS BOUNDARY TODAY. THAT BEING SAID...AFTER THE MORNING SNOW IN
OUR EAST...PCPN SHOULD INCREASE AGAIN THIS AFTERNOON IN RESPONSE
TO INCREASING DEEP LAYER ASCENT...WITH FOCUS OF LOW LEVEL
FRONTOGENESIS AND PCPN SHIFTING TO THE WEST OVER TIME...AND LIKELY
GETTING TO AS FAR WEST AS BILLINGS AND SHERIDAN BY LATE
AFTERNOON. HAVE ADDED THIS DETAIL IN THE WIND AND POP GRIDS.
OUR CENTRAL PARTS SEEM POISED FOR A SNOW EVENT TONIGHT AS NW WAVE
COMES THROUGH. MUST NOTE THAT MID LEVEL LAPSE RATES EXPECTED TO BE
QUITE STEEP...ABOVE 7C/KM FROM 700-500MB...SO EXPECT SOME HEAVY
SNOW ALONG A FRONTOGENETIC BAND...WHICH MAY BE ADDITIONALLY
ENHANCED BY CONVERGENCE IN THE LEE OF THE SNOWIES. TOUGH TO
FIGURE WHERE EXACTLY THIS MIGHT SET UP...BUT BILLINGS IS A
POSSIBILITY. GREATEST CONFIDENCE FOR SEVERAL INCHES OF SNOW IS IN
OUR NW UPSLOPE AREAS TO THE SE OF BILLINGS...IE BIG HORN AND
SHERIDAN COUNTIES. WILL ISSUE ADVISORIES FROM TONIGHT INTO
WEDNESDAY FOR THIS AREA. SFC BOUNDARY SHOULD HANG UP ALONG THE
EAST SIDE OF THE BIG HORN MTNS TONIGHT...SO EXPECT FAIRLY LIGHT
WINDS IN SHERIDAN ITSELF SO COULD BE A GOOD SNOW EVENT THERE.
OVERALL AM THINKING 3-6 INCHES FOR THE FOOTHILLS AND 6-12 OVER THE
BIG HORNS...WHICH ARE OBVIOUSLY FAVORED IN THE MOIST AND UNSTABLE
NW FLOW. SECONDARY PV MAX ROTATES SOUTH INTO EARLY WEDNESDAY SO
WILL TAKE ADVISORY ALL THE WAY TO NOON TOMORROW.
OUR WESTERN LOWER ELEVATIONS WILL SEE VERY LITTLE SNOW DUE TO
PERSISTENT DOWNSLOPE WINDS. WESTERN SLOPES OF THE BEARTOOTH
ABSAROKA AND CRAZY MTNS WILL DO QUITE WELL THOUGH...ON THE ORDER
OF 6-12 INCHES...THOUGH DO NOT SEE A LONG ENOUGH DURATION EVENT TO
WARRANT A WARNING...ESPECIALLY CONSIDERING THE MID LEVEL WINDS
WILL VEER FROM WEST TO NORTHWEST OVER TIME THUS SHIFTING THE
ASPECTS ON WHICH THE HEAVIEST AMTS WILL FALL.
TEMPS TODAY AND TOMORROW WILL CONTINUE TO BE WARMEST IN OUR WEST
AND COLDEST IN OUR EAST...WITH 30 DEGREES OR MORE OF DIFFERENCE.
AS WEDNESDAY SYSTEM DEPARTS WE WILL SEE A RETURN OF ANTICYCLONIC
FLOW ALOFT AND LEE SIDE SFC TROFFING BY WEDNESDAY NIGHT. LOOKS
LIKE POTENTIAL ADVISORY GUSTS ONCE AGAIN AT LIVINGSTON BY LATE
WEDNESDAY NIGHT.
JKL
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
SOME SIGNIFICANT CHANGES TO THE EXTENDED FOR THIS PACKAGE REVOLVE
AROUND THE POTENTIAL ARCTIC SURGE WE WERE LOOKING AT EARLY NEXT
WEEK. THE ECMWF HAS COMPLETELY GONE AWAY FROM THIS SCENARIO
BY BRINGING THE PACIFIC RIDGE FURTHER INLAND THAN THE GFS THEREBY
DEFLECTING THE ARCTIC AIR EASTWARD TO THE DAKOTAS...WHILE THE GFS
HAS THE COLD AIR ENTRENCHED UP AGAINST THE DIVIDE. THE 12Z ECMWF
STARTED HINTING AT THIS TREND SO THE 00Z ECMWF IS NOT A SURPRISE.
ENSEMBLE SPREADS ARE NOT QUITE AS WIDE AS THE 12Z RUN OF THE
ECMWF. OUR EXTREME FORECAST INDEX POINTS TO THE DAKOTAS AS WHERE
THE BULK OF THE COLDEST AIR WILL GO AS WELL. IN ORDER TO REMOVE
THE RISK OF LARGE FORECAST ERRORS WE WILL TREND THE FORECAST TO A
BLEND DOMINATED BY THE ECMWF...THUS INCREASING OUR TEMPERATURE
FORECASTS QUITE A BIT FOR EARLY NEXT WEEK ACROSS MAINLY OUR
WESTERN ZONES. HOWEVER...WE WILL REMAIN LEARY OF A POTENTIAL
SWITCH IN THE ECMWF. CHANGES WILL ALSO BE REFLECTED BY LOWERING
POPS A BIT FOR EARLY NEXT WEEK. BT
&&
.AVIATION...
STRONG SW WINDS WILL CONTINUE AT KLVM THIS MORNING WITH GUSTS
OVER 50 KNOTS AT TIMES. THESE WINDS WILL DECREASE BY 18Z. AREAS OF
LIGHT SNOW AND LOCAL CONDITIONS DOWN TO IFR WILL CONTINUE FROM
KMLS EASTWARD BEFORE IMPROVING BY 00Z. A LITTLE FURTHER WEST...LOWERING
CEILINGS AND AREAS OF SNOW ARE EXPECTED TO INCREASE OVER SOUTH
CENTRAL MONTANA THIS AFTERNOON AND INTO THE EVENING AFFECTING KLVM
AND KBIL AS WELL AS KSHR AND THE BIG HORN MOUNTAINS REGION. MVFR
TO LOCAL LIFR SHOULD BE EXPECTED WITH MOUNTAIN OBSCURATIONS. BT
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 040 021/032 020/042 030/047 020/029 017/020 902/015
7/W 95/S 00/B 03/W 30/B 13/S 32/J
LVM 041 027/036 028/043 033/044 017/030 012/024 001/020
5/W 62/S 01/N 03/W 31/B 23/S 22/J
HDN 039 017/030 014/035 024/046 014/027 011/020 906/013
7/S 95/S 00/B 03/W 31/B 23/S 32/J
MLS 017 005/019 006/028 020/041 012/023 008/011 912/007
8/S 54/S 10/B 04/W 41/B 24/S 21/B
4BQ 032 013/026 005/032 021/047 015/024 011/018 909/012
8/S 85/S 10/B 03/W 41/B 24/S 32/J
BHK 015 000/013 903/026 018/041 012/019 003/006 914/003
+/S 43/S 10/B 04/W 51/B 23/S 21/B
SHR 041 018/030 011/040 022/051 015/028 011/022 904/016
5/W 96/S 00/B 02/W 31/B 24/S 32/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT FROM 5 PM THIS AFTERNOON TO
NOON MST WEDNESDAY FOR ZONE 38.
WIND ADVISORY IN EFFECT UNTIL 5 PM MST THIS AFTERNOON FOR
ZONE 65.
WY...WINTER WEATHER ADVISORY IN EFFECT FROM 5 PM THIS AFTERNOON TO
NOON MST WEDNESDAY FOR ZONE 99.
WINTER WEATHER ADVISORY IN EFFECT FROM 3 PM THIS AFTERNOON TO
NOON MST WEDNESDAY FOR ZONE 98.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
520 AM CST TUE DEC 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 513 AM CST TUE DEC 31 2013
UPPER AIR DATA CONTINUES TO SHOW THE REGION UNDER THE INFLUENCE
OF NORTHWESTERLY FLOW...WITH LOW PRESSURE CONTINUING TO SPIN OVER
THE HUDSON BAY REGION AND THE MAIN ASSOCIATED TROUGH EXTENDING
SOUTH THROUGH THE MIDWEST TOWARD THE GULF COAST...WHILE HIGH
PRESSURE REMAINS ANCHORED OFF THE SRN COAST OF CA. BEEN A QUIET
NIGHT WITH NO NOTABLE DISTURBANCES MOVING THROUGH...AND OUTSIDE OF
A BIT OF CIRRUS SLIDING IN FROM THE NORTHWEST ASSOCIATED WITH AN
UPPER LEVEL STREAK TO THE N/NE OF THE CWA...SKIES ARE MOSTLY
CLEAR. AT THE SURFACE...HIGH PRESSURE CONTINUES TO GRADUALLY SLIDE
OFF TO THE EAST...BUT WINDS FOR MUCH OF THE CWA REMAIN ON THE
LIGHT AND VARIABLE SIDE. WITH TIME...WINDS WILL BECOME MORE
SOUTHERLY AS THE CWA COMES UNDER MORE INFLUENCE OF LOW PRESSURE TO
THE WEST.
LOOKING TO THE REST OF TODAY...THE FORECAST REMAINS A DRY
ONE...WITH A SWITCH IN WINDS EXPECTED AND ABOVE AVERAGE HIGHS FOR
MOST LOCATIONS. SOUTHERLY WINDS ARE EXPECTED TO REMAIN THROUGH
MOST OF THE MORNING HOURS...BUT AN FRONTAL BOUNDARY APPROACHING
FROM THE WEST WILL BRING A GRADUAL SWITCH TO THE WEST. THIS FRONT
WILL CONTINUE TO MAKE ITS WAY THROUGH THE CWA DURING THE AFTERNOON
HOURS...AND BY 00Z THIS EVENING...MODELS ARE IN PRETTY GOOD
AGREEMENT SHOWING THE FRONT IN THE VICINITY OF THE NEB/KS STATE
LINE...USHERING IN N/NERLY WINDS. MAIN UNCERTAINTY FOR TODAY LIES
WITH HIGH TEMPERATURES. THE RAP DIDNT DO TOO BAD YESTERDAY AND
HAVE TEMPS TODAY AGAIN TRENDED THAT WAY...WHICH IS WARMER THAN
OTHER MODELS/GUIDANCE...BUT THIS FRONT REALLY DOESNT HAVE A COOLER
AIR PUSH WITH IT...AND INCREASED MIXING AHEAD/ALONG THE FRONT
LOOKS TO BRING 40S/50S AGAIN TO MOST OF THE CWA. GOING WITH
STRAIGHT RAP/HRRR WOULD SUGGEST FORECAST HIGHS ARE NOT HIGH ENOUGH
FOR SOME...BUT AM CONCERNED ABOUT THE AMOUNT OF UPPER LEVEL CLOUD
COVER THAT LOOKS TO AFFECT THE CWA FOR AT LEAST THE FIRST HALF OF
THE DAY. TEMP/CLOUD TRENDS WILL BE THE MAIN THING FOR THE DAY
SHIFT TO MONITOR FOR TODAY.
AS WE GET INTO THIS EVENING/OVERNIGHT...PRECIPITATION CHANCES MAKE
A RETURN. ANOTHER UPPER LEVEL SHORTWAVE DISTURBANCE WILL STARTING
MAKING ITS WAY SOUTHEAST OUT OF THE NRN ROCKIES OVERNIGHT...BUT BY
12Z WEDNESDAY THE BULK IS STILL JUST OFF TO THE NW OF THE CWA.
EXPECTING DRY CONDITIONS THROUGH AT LEAST MIDNIGHT...IT MAY EVEN
BE A FEW HOURS BEYOND THAT BEFORE SNOW CHANCES BEGIN MOVING INTO
NRN PORTIONS OF THE CWA. THROUGH THE EARLY MORNING HOURS...KEPT
ANY POPS CONFINED TO LOCATIONS NORTH OF HIGHWAY 6...WITH 40-50
POPS ALONG/NORTH OF HIGHWAY 92. SOME ACCUMULATION WILL BE
POSSIBLE...POTENTIALLY NEAR A HALF INCH THOSE FAR NRN LOCATIONS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 513 AM CST TUE DEC 31 2013
THE BIGGEST CONCERN WILL BE DETERMINING TIMING OF SNOW FOR
WEDNESDAY.
WE BEGIN THE LONG TERM ON WEDNESDAY AS A LOW-AMPLITUDE SHORTWAVE
TROUGH MOVES IN WITHIN NORTHWEST FLOW AND BEGINS TO DEEPEN OVER
OUR AREA AND CONTINUE TO DO SO AS IT TRAVERSES EAST. THIS WILL BE
A QUICK HITTER...AND MODEL SOLUTIONS GENERALLY AGREE THAT THE AXIS
OF THIS WAVE IS TRENDING A SOONER DEPARTURE. THIS QUICK HIT MEANS
THAT SNOW AMOUNTS WILL NOT AMOUNT TO MUCH AND I HAVE KEPT TOTAL
SNOW ACCUMULATIONS LESS THAN 2 INCHES AS THE PREVIOUS FORECAST
DID...WITH THE HIGHER AMOUNTS NORTH/NORTHEAST. MODELS/ENSEMBLES
SUCH AS NAM...SREF...AND NMM WRF INDICATE THAT THERE COULD BE SOME
LINGERING FLURRIES IN THE EVENING. ENSEMBLES CONTINUE TO TREND
COLDER FOR HIGHS AND I HAVE LOWERED THEM FROM PREVIOUS
FORECASTS...STRUGGLING TO GET INTO THE TEENS TO LOWER 20S FOR THE
MOST PART. WITH THE QUICKER DEPARTURE OF THE WAVE...I BACKED OFF
WIND SPEEDS. MILDER WEATHER WILL TRY TO RETURN BY FRIDAY WITH A
QUICK MOVING RIDGE...BUT ANOTHER SHOT OF MUCH COLDER AIR IS ON ITS
WAY FOR THE WEEKEND...REINFORCED EVEN FURTHER BY A MUCH COLDER
ARCTIC AIR MASS. HIGHS ON MONDAY MAY NOT MAKE IT OUT OF THE SINGLE
DIGITS...AND WITH SUCH STRONG COLD AIR ADVECTION...WIND SPEEDS
SHOULD BE STRONGER. THIS COULD SET US UP FOR WIND CHILLS LOW
ENOUGH TO MENTION IN THE HWO FOR MONDAY. WITH THE REINFORCING SHOT
OF VERY COLD AIR WILL LIKELY COME SOME STRATUS AND PERHAPS SOME
LIGHT SNOW. IT DOES NOT APPEAR THAT THIS WOULD BE A SCENARIO THAT
WOULD GIVE US SERIOUS SNOW ACCUMULATIONS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 513 AM CST TUE DEC 31 2013
MAIN FORECAST CONCERNS FOR THIS TAF PERIOD LIE WITH CHANGING WIND
DIRECTION THROUGH THE DAY...THEN PRECIP CHANCES LATE IN THE
PERIOD. THE DAY WILL START OUT WITH SOUTHERLY WINDS...BUT ANOTHER
SURFACE FRONTAL BOUNDARY IS EXPECTED TO PUSH THROUGH THE
REGION...BRINGING MORE OF A WESTERLY COMPONENT THROUGH THE
MID/LATE MORNING HOURS...WITH THE AFTERNOON BECOMING MORE
NORTHERLY WITH TIME. SPEEDS ARE EXPECTED TO TOP OUT BETWEEN 10 AND
15 MPH OUT AHEAD OF THE FRONT. AT THIS TIME KEPT CONDITIONS VFR
THROUGH THE PERIOD...BUT CONFIDENCE IN THAT FOR THE LAST FEW HOURS
OF THIS PERIOD IS ON THE LOW SIDE...AS AN UPPER LEVEL DISTURBANCE
BEGINS TO SLIDE INTO THE REGION. THE CHANCE FOR SOME LIGHT SNOW
HAS BEEN ADDED...AND ITS POSSIBLE UPCOMING TAF FORECASTS MAY NEED
TO LOWER CEILINGS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ADO
LONG TERM...HEINLEIN
AVIATION...ADO
AREA FORECAST DISCUSSION
NWS PORTLAND OR
746 AM PST TUE DEC 31 2013
.SYNOPSIS...A WEAK COLD FRONT WILL MOVE THROUGH MAINLY THE
NORTHERN PART OF SOUTHWEST WASHINGTON AND NORTHWEST OREGON TUESDAY
FOR MORE AREAS OF LIGHT RAIN. THE UPPER RIDGE WILL BECOME
REESTABLISHED TUESDAY NIGHT AND WEDNESDAY FOR DRYING BUT WITH MORE
AREAS OF FOG AND LOW CLOUDS...WHICH WILL CONTINUE INTO THURSDAY. THE
NEXT STRONGER FRONT WILL SPREAD IN LATER THURSDAY AND THURSDAY NIGHT
FOR A DECENT RAIN. SNOW LEVELS WILL FALL TO NEAR OR BELOW PASS
ELEVATIONS LATE THURSDAY NIGHT AND FRIDAY BUT PRECIPITATION WILL BE
WANING AT THAT POINT...SO ONLY LIGHT SNOW IS EXPECTED IN THE
CASCADES. THE MOST LIKELY SCENARIO FOR THIS WEEKEND AND EARLY NEXT
WEEK IS A RETURN TO THE UPPER RIDGE AND DRY WEATHER.
&&
.QUICK MORNING UPDATE...INCREASED POPS IN AN EAST TO WEST BAND
EXTENDING FROM VANCOUVER TO AURORA WHERE ISENTROPIC LIFT NEAR 290K
AHEAD OF A WEAK FRONT IS AIDING IN LIGHT RAIN DEVELOPMENT. NO MODEL
SEEMS TO HAVE A GREAT HANDLE ON THE SITUATION INCLUDING THE HRRR SO
WILL EXAMINE THIS FURTHER TO SEE IF POPS NEED TO BE ADJUSTED FOR THIS
AFTERNOON.
ALSO...CANCELED THE AIR STAGNATION ADVISORY FOR THE PORTLAND METRO
AREA WHERE RAIN SHOULD EASE POLLUTION LEVELS AS A RESULT OF WET
DEPOSITION. THIS COUPLED WITH EASTERLY FLOW COMING OUT OF THE GORGE
WEDNESDAY AND A COMPLETE MIX OUT EXPECTED THURSDAY
AFTERNOON/EVENING...72 HOURS OF STAGNANT CONDITIONS SEEM UNLIKELY TO
BE MET FROM THIS POINT FORWARD. GIVEN THE RAIN IN MCMINNVILLE AND
SALEM...THE CENTRAL VALLEY COULD ARGUABLY BE DROPPED...BUT WILL LET
IT RIDE FOR NOW AND REEVALUATE LATER TODAY. /NEUMAN
.SHORT TERM...TUESDAY THROUGH THURSDAY NIGHT...
WEAK COLD FRONT IS MAKING ITS WAY CLOSER TO SHORE EARLY THIS MORNING
BASED ON SATELLITE OBSERVATIONS. NOTE THAT KLGX (COASTAL WASHINGTON)
RADAR IS DOWN. SATELLITE SHOWS A SEMI ORGANIZED BAND OFF THE S WA
COAST...WITH ADDITIONAL MOISTURE LOCATED JUST ON THE BACK SIDE OF
THE FRONT WELL BACK BEHIND MORE LOOSELY ORGANIZED MOISTURE. HOQUIAM
HAS BEEN SHOWING ON AND OFF LIGHT RAIN TO THIS POINT...BUT NOTHING
THIS FAR SOUTH. THE FRONT IS PROGGED TO MOVE INTO OUR NORTH COASTAL
AREAS LATER THIS MORNING THAN STALL OUT AS A WEAK WAVE IN WNW FLOW
RIDES OVER IT. NOT EXPECTING A WHOLE LOT OF PRECIPITATION...BUT
STILL A BETTER CHANCE THAN YESTERDAY. AREAS FROM ABOUT SALEM
SOUTHWARD PROBABLY WILL NOT SEE MUCH AS HIGHER PRESSURE LIMITS
SOUTHWARD MOVEMENT OF THE FRONT...WHILE AREAS TO THE NORTH HAVE A
MUCH BETTER CHANCE LATER THIS MORNING INTO EARLY AFTERNOON.
MODELS REMAIN IN GOOD AGREEMENT THAT SURFACE HIGH PRESSURE AHEAD F
THE UPPER RIDGE OFFSHORE WILL ALLOW FOR RAPID DRYING TUESDAY NIGHT
AND WEDNESDAY. HOWEVER...THIS WILL MAKE IT MORE CONDUCIVE
TO FORMING MORE FOG AND LOW CLOUDS...WHICH WILL LIKELY NOT CLEAR IN
THE AFTERNOONS. CONTINUE TO UNDERCUT GUIDANCE WHICH HAS BEEN TOO HIGH
FOR THE DURATION OF THIS STAGNANT COOL VALLEY LOW LEVEL AIR MASS. THE
NAM SUGGEST A BIT OF AN OFFSHORE GRADIENT DEVELOPING...SO BEST BET
FOR CLEARING WILL BE NEAR THE GORGE.
THERE AN UPPER LEVEL CIRCULATION CURRENTLY NEAR 38N/143W THAT WILL
MOVE THROUGH THE PACIFIC NORTHWEST WEDNESDAY EVENING. MODELS TO THIS
POINT HAVE WAVERED CONSIDERABLY IN HANDLING THIS WAVE...SOME EARLIER
THIS WEEK SUGGESTING IT WOULD SLIDE SOUTH...WITH THE MODEL CONSENSUS
OF LATE SUGGESTING IT WOULD RIDE NORTH...WHICH MAKES SENSE WITH THE
BUILDING OFFSHORE UPPER RIDGE. 0Z NAM AND ECMWF AND CANADIAN NOW CAME
IN WITH A WAVE THAT EVENTUALLY SKIRTS THROUGH THE NORTHERN TIER OF
OUR AREA AND RIDES OVER THE LINGERING FRONTAL BOUNDARY FOR SOME VERY
LIGHT RAIN ALONG AND NORTH OF THE COLUMBIA RIVER. NOT A VERY HIGH
IMPACT SITUATION...BUT WILL KEEP SOME VERY LOW POPS FOR THESE AREAS
BUT DO NOT EXPECT IT TO AMOUNT TO MUCH WITH SURFACE HIGH PRESSURE IN
PLACE AND A NORTHWARD MOVING WARM FRONT. EVEN THESE AREAS DRY OUT
INTO THURSDAY MORNING.
THERE IS ANOTHER STRONGER FRONT THAT WILL APPROACH THE AREA EARLY
THURSDAY AND MOVE INTO SOUTHWEST WASHINGTON AND NORTHWEST OREGON
LATER THURSDAY AND THURSDAY NIGHT. THIS LOOKS LIKE THE BEST FRONT WE
HAVE SEEN IN QUITE A WHILE...AND WE SHOULD SEE A DECENT DOSE OF RAIN
ACROSS OUR FORECAST AREA. SNOW LEVELS WILL REMAIN RATHER HIGH
THROUGHOUT MOST OF THIS EVENT...FINALLY DROPPING TO NEAR OR BELOW THE
CASCADE PASSES LATE THURSDAY NIGHT OR FRIDAY. BUT PRECIPITATION WILL
BE WANING AT THAT POINT...SO SNOW AMOUNTS WILL BE RATHER LIGHT IN THE
CASCADES. HAVE FOLLOWED THE 00Z NAM/ECMWF FOR TIMING BASED ON WPC`S
MODEL DIAGNOSTIC DISCUSSION. THE GFS CONSIDERABLY SLOWER. THE MAIN
UPPER LEVEL FORCING STILL PASSES BY TO THE NORTH AND THUS THE
PRECIPITATION WILL BE ON THE LIGHTER SIDE INITIALLY FOR THE VALLEYS
AND BETTER FOR ELEVATED TERRAIN...BUT THERE IS A DECENT
FRONTOGENETICAL SIGNATURE IN THE 850-700 MB LAYER AND MODEST PW
VALUES TO SUGGEST SOME DECENT RAIN BANDS EVEN FOR THE LOWLANDS
THURSDAY EVENING RIGHT WITH THE FRONT.THURSDAY WILL BE THE WARMEST
DAY AND YOU MAY ACTUALLY SEE THE SOUTH WIND BLOWING WHICH WILL BE THE
FIRST SIGNS OF A CHANGING AIR MASS...ALBEIT TEMPORARY.
WE MAY FINALLY GET OUT OF THESE RATHER STAGNANT CONDITIONS WITH THIS
FRONT...BUT THIS TRANSITION MAY NOT OCCUR UNTIL LATE THURSDAY OR
THURSDAY NIGHT. THE ONLY PROBLEM IS THAT THE WEEKEND LOOKS TO BE
SOMEWHAT STAGNANT UNDER A RETURNING RIDGE. KMD
.HYDROLOGY...THE HIGHEST TIDE OF THE 13/14 WINTER WILL BE ON NEW
YEARS DAY. WHILE RIVERS ARE LOW FOR THIS TIME OF YEAR AND TIDAL
ANOMALIES ARE NOTHING TO WRITE HOME ABOUT...THERE IS A CHANCE A FEW
ROADS ALONG THE COAST MAY HAVE AN ISSUE WITH FLOODING. THE MAIN AREA
OF CONCERN IS AROUND TILLAMOOK WHERE TILLAMOOK RIVER...FRASIER AND
BROUTON ROADS MAY BE VULNERABLE TO BRIEF FLOODING DURING HIGH TIDE ON
NEW YEARS DAY. /NEUMAN
.LONG TERM...MINOR CHANGES. PREVIOUS DISCUSSION GENERALLY FOLLOWS...
FRIDAY THROUGH MONDAY...THE FCST MODELS TRENDING
TOWARDS DRIER WEATHER LATE FRI THROUGH THE WEEKEND AS UPPER LEVEL
RIDGING RESTRENGTHENS OVER THE NE PAC. REMOVED ALL PRECIP CHANCES OUT
OF THE FCST OVER THE WEEKEND BASED ON THE PRETTY GOOD AGREEMENT OF
THE FCST ENSEMBLES FOR NEXT WEEKEND. THE NEXT CHANCE FOR
PRECIPITATION APPEARS TO BE A SYSTEM THAT WILL ATTEMPT TO PUSH
THROUGH THE TOP OF THE RIDGE EARLY NEXT WEEK. PYLE
&&
.AVIATION...MOSTLY VFR CONDITIONS EARLY THIS MORNING EXCEPT FOR
PARTS OF THE NORTHERN AND CENTRAL WILLAMETTE VALLEY WHERE THERE
HAS BEEN PERIODS OF LOCALIZED MVFR/IFR CONDITIONS. CIGS ALONG THE
NORTH COAST WILL LOWER TO MVFR WITHIN THE NEXT FEW HOURS AS A WARM
FRONT APPROACHES. THIS FRONT WILL SPREAD WIDESPREAD IFR CIGS
ACROSS THE NORTH LATER THIS MORNING WITH OCCASIONAL MVFR VSBYS IN
DRIZZLE. SOUTHERN AREAS SHOULD REMAIN MOSTLY VFR WITH A BRIEF
PERIOD OF MVFR LATER THIS MORNING. HIGHER TERRAIN TO REMAIN
OBSCURED IN CLOUDS INTO THE AFTERNOON. CONDITIONS SHOULD IMPROVE
INLAND AFTER 20Z WITH MVFR/VFR CONDITIONS INTO THE EVENING.
HARTLEY
KPDX AND APPROACHES...VFR FOR NEXT FEW HOURS...BUT AREAS OF IFR
STRATUS AND FOG ARE DEVELOPING AND SHOULD OVERTAKE THE KPDX OPS
AREA BY 13Z. CIGS WILL LIFT IN THE AFTERNOON AND EXPECT VFR
CONDITIONS AFT 21Z. HARTLEY
&&
.MARINE...ONLY CHANGE MADE TO THE MARINE FORECAST WAS TO ADD A
SMALL CRAFT ADVISORY FOR THE COLUMBIA RIVER BAR THIS AFTERNOON
DURING THE VERY STRONG EBB CURRENT. PREVIOUS DISCUSSION
FOLLOWS...LITTLE CHANGE FOR NEXT SEVERAL DAYS. SEAS HOLDING AT 7
TO 8 FT TONIGHT...BUT WILL SLOWLY SUBSIDE ON TUE AND TUE NIGHT.
NEXT THREAT OF ENHANCED WINDS NOT UNTIL LATER THU NIGHT AND FRI
WHEN A FRONT WILL PUSH ACROSS THE REGION. THIS FRONT LIKELY TO POP
20 TO 25 KT S WINDS...WITH SEAS BUILDING BACK TO 10 FT ON FRI.
THEN HIGH PRESSURE IS EXPECTED TO REDEVELOP...KEEPING CONDITIONS
RATHER BENIGN ON SAT AND SUN. ROCKEY/HARTLEY
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 4 PM PST THURSDAY FOR CENTRAL
WILLAMETTE VALLEY-SOUTH WILLAMETTE VALLEY.
WA...NONE
PZ...SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 6 AM
PST EARLY THIS MORNING.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 2 PM
THIS AFTERNOON TO 6 PM PST THIS EVENING.
&&
$$
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 RENO NV
123 PM PST TUE DEC 31 2013
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN LIGHT WINDS AND VALLEY INVERSIONS
OVER THE REGION THROUGH THURSDAY WITH REDUCED AIR QUALITY. PERIODS
OF HIGH CLOUDS WILL STREAM OVERHEAD. A STORM PASSING TO THE NORTH
MAY HELP ERODE THE INVERSIONS FRIDAY. THE WEATHER PATTERN OVER THE
WEST MAY CHANGE NEXT WEEK BUT THERE ARE STILL NO SIGNIFICANT
STORMS ON THE HORIZON.
&&
.SHORT TERM...
WELL THE METEOROLOGICAL EXCITEMENT OF WINTER 2013-14 JUST KEEPS
ON GOING - SAID NO ONE AT NWS RENO. HIGH PRESSURE WILL BUILD BACK
INTO THE REGION THROUGH THURSDAY. THIS ALONG WITH LIGHT WINDS WILL
MAINTAIN INVERSIONS IN THE LOWER VALLEYS, PER NAM FORECAST
SOUNDINGS. WE MAY SEE SOME MIXING BUT ONLY TO 500-1000 FT AGL,
WHICH WILL PROMOTE REDUCED AIR QUALITY. SLIGHTLY HIGHER LOW LEVEL
RH AND CLEAR SKIES MAY HELP FZFG REDEVELOP AROUND FALLON/TRUCKEE
LATE TONIGHT. HRRR GUIDANCE DOES DEVELOP FOG NEAR NFL AFTER
MIDNIGHT BUT IT`S QUITE LOCALIZED IN THE WETLANDS AREA NE OF TOWN.
QUICK MOVING TROF FORECAST TO DROP INTO THE EASTERN GREAT BASIN
FRIDAY. WHILE ENSEMBLE SPREADS ARE ABOVE NORMAL FOR THIS SYSTEM,
THERE`S BEEN AN EASTWARD TREND IN THE TROF TRAJECTORY. THEREFORE
WE`VE REMOVED POPS FOR FRI-FRI NIGHT. THIS SYSTEM MAY BRING ENOUGH
WIND AND COOLING ALOFT TO YIELD BETTER MIXING FRIDAY AND CLEAR OUT
INVERSIONS IN ALL BUT THE LOWEST VALLEYS. CONFIDENCE IN THIS IS
ADMITTEDLY ONLY MEDIUM BASED ON UNCERTAINTIES IN THE TROF PATH AND
HOW INCREASED THE WINDS/MIXING WILL END UP BEING. SHOULD MIXING BE
BETTER THAN EXPECTED - HIGHS FRIDAY MAY BE A GOOD 5-7 DEGREES
WARMER THAN CURRENTLY FORECAST. CS
.LONG TERM...SATURDAY THROUGH TUESDAY...
TROUGH WILL BE EXITING TO THE EAST OVER THE WEEKEND WITH A LIGHT
NORTHEAST FLOW COOLING TEMPERATURES DOWN A BIT AS SURFACE HIGH
BUILDS ACROSS THE GREAT BASIN. WARMING ALOFT WILL HELP ESTABLISH
INVERSIONS AGAIN, AND AFTER A POSSIBLE BREAK FRIDAY, MIXING AND
TRANSPORT WILL BECOME POOR, ESPECIALLY SUN-MON. MODELS ARE
BEGINNING TO CONVERGE ON A WEAK SYSTEM UNDERCUTTING THE EAST
PACIFIC RIDGE AND POSSIBLY BRINGING SOME LIGHT PRECIPITATION TO
THE REGION BY TUE. DID NOT INCREASE POPS BUT DID SPREAD THE SLIGHT
CHANCES FURTHER EAST AND SOUTH. MODEL RUNS OVER THE WEST PACIFIC
INDICATE UPPER JET PUSHING FURTHER EASTWARD INTO THE CENTRAL
PACIFIC BY THE SECOND WEEK OF JANUARY. GEFS/GEFSBC FORECAST A
MODERATE MJO IN THE WEST PACIFIC BY JAN 14TH SUPPORTING THIS
EASTWARD EXPANSION. UNFORTUNATELY, AT LEAST FOR THE INTERIM, THIS
WOULD ONLY ACT TO PUMP THE RIDGE BACK UP NEAR THE WEST COAST OR
JUST OFFSHORE. NO MAJOR SYSTEMS ARE ON THE HORIZON JUST YET. WE
WAIT. HOHMANN
&&
.AVIATION...
SKIES WILL BE CLEAR OVERNIGHT WITH SOME PATCHY FREEZING FOG
AROUND KNFL AND ALSO IN THE MARTIS AND SIERRA VALLEYS LATE TONIGHT
AND NEW YEARS DAY MORNING. HAZY CONDITIONS IN THE RENO-SPARKS-
CARSON CITY AREA BUT OTHERWISE VFR. LIGHT WINDS. HOHMANN
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1027 AM MST TUE DEC 31 2013
.UPDATE...
ISSUED AT 940 AM MST TUE DEC 31 2013
UPDATED GRIDS/ZONES TO INCREASE POPS A BIT OVER LAKE COUNTY...WHERE
PERSISTENT SHSN CONTINUE...AND ADJUST AREAL SKY COVERAGE. ROSE
UPDATE ISSUED AT 746 AM MST TUE DEC 31 2013
BASED ON LATEST OBS EXTENDED THE LIFR FOG IN KALS UNTIL 16Z. VIS
SHOULD IMPROVE AFTER 16Z WITH LIFR CIGS BREAKING BY 17Z. -KT
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM MST TUE DEC 31 2013
NEXT SHORTWAVE WILL BE RIDING THROUGH NORTHWEST FLOW ALOFT INTO
NORTHWEST COLORADO LATE TONIGHT. AHEAD OF THIS SYSTEM TODAY SHOULD
BE A WARM DAY WITH TEMPERATURES CLIMBING INTO THE 50S. ALREADY
STARTING TO SEE SOME WAVE CLOUDINESS AND THESE WILL CONTINUE TO
THICKEN AND SPREAD EASTWARD AS MORE MOISTURE EVIDENT IN WV PICS
CONTINUES TO STREAM IN FROM THE NORTHWEST THIS MORNING. THIS WILL
SERVE TO CUT BACK ON MAX TEMPS A BIT THIS AFTERNOON IN SOME
PLACES...ESPECIALLY ALONG THE ARKANSAS RIVER VALLEY WHERE WINDS MAY
HAVE A HARDER TIME MIXING DOWN. HRRR DEPICTS THIS IN SFC T FIELDS
NICELY. OTHER AREA WHERE TEMPS WILL REALLY STRUGGLE WILL BE ACROSS
THE SAN LUIS VALLEY WHERE SNOW COVER HAS ALREADY DROPPED MAX TEMPS
DOWN TO AROUND 10 BELOW ZERO THIS MORNING. DEPENDING ON HOW QUICKLY
AND THICKLY HIGH CLOUDS SPREAD IN LATER THIS MORNING...TEMPERATURES
MAY STRUGGLE TO GET INTO THE MID/UPPER TEENS. HAVE CUT BACK ON MAX
TEMPS THERE CONSIDERABLY OVER GUIDANCE. MEANWHILE FOG IN THE SAN
LUIS VALLEY SHOULD THIN SOME AS HIGH CLOUDINESS MOVES IN THROUGH THE
MORNING...THEN DISSIPATE ENTIRELY BY 16Z. MEANWHILE...CENTRAL
MOUNTAINS WILL SEE OROGRAPHIC SNOW SHOWERS SPREAD IN DURING THE
MORNING...THEN DECREASE A BIT TOWARDS AFTERNOON. ANY ACCUMULATIONS LOOK
LIGHT AT THIS POINT...AND CONFINED MOSTLY TO THE HIGHER ELEVATIONS
OF THE SAWATCH AND MOSQUITO RANGES.
TONIGHT...SNOW SHOULD START TO RAMP UP ALONG THE CONTINENTAL DIVIDE
TOWARDS 06Z...WITH A FEW SNOW SHOWERS POSSIBLY SPREADING INTO THE
HIGHER PEAKS OF THE SANGRES TOWARDS 12Z. HEAVIEST ACCUMULATIONS
WILL STAY CONFINED TO THE CENTRAL MOUNTAINS WHERE ANOTHER 1 TO 3
INCHES WILL BE POSSIBLE OVERNIGHT. WESTERLY WINDS INTO THE LEE SIDE
SFC LOW WILL KEEP MIN TEMPS WARM ALONG THE LOWER EASTERN SLOPES OF
THE SE MTS. A COLD FRONT WILL DROP THROUGH THE SOUTHEAST PLAINS
AFTER 09Z BRINGING AN INCREASE IN NORTH WINDS TOWARDS DAWN. GFS AND
ECMWF APPEAR TO HAVE TRENDED TOWARDS A MORE AMPLIFIED SOLN WITH THE
UPPER TROF AS IT MOVES ACROSS SE CO TOWARDS MORNING...BUT FOR NOW
THINK ANY LIGHT PRECIP WILL HOLD OFF UNTIL AFTER 12Z. -KT
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 516 AM MST TUE DEC 31 2013
NOT MANY METEOROLOGICAL ADJUSTMENTS NEEDED DURING THE LONGER TERM
WITH PRIMARY CONCERNS CONTINUING TO BE POPS...GUSTY WINDS AT TIMES
AND TEMPERATURES.
RECENT LONGER TERM COMPUTER SIMULATIONS INDICATES THAT A COUPLE
OF UPPER DISTURBANCES WILL CROSS THE FORECAST DISTRICT DURING THE
LONGER TERM WITH THE INITIAL SYSTEM IMPACTING THE CWFA NEW YEARS
DAYS AND ANOTHER SYSTEM IMPACTING SOUTHERN COLORADO DURING THE
WEEKEND.
THEN GENERALLY DRY AND MILD TO WARM CONDITIONS SHOULD DEVELOP
OVER THE FORECAST DISTRICT FROM THURSDAY INTO FRIDAY AS DRY
NORTHWESTERLY UPPER FLOW IMPACTS SOUTHERN COLORADO.
A RETURN TO COOLER AND UNSETTLED CONDITIONS IS THEN ANTICIPATED
THIS WEEKEND AS ANOTHER UPPER DISTURBANCE IMPACTS THE FORECAST
DISTRICT. FINALLY...GUSTY WINDS WILL BE POSSIBLE OF MANY LOCATIONS
FROM WEDNESDAY INTO WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1011 AM MST TUE DEC 31 2013
AVN FORECAST FOR THE NEXT 24-36 HOURS IS A BIT OF A CHALLENGE.
FIRST CONCERN WILL BE FG PROBABILITIES FOR KALS TONIGHT. A WEAK
DISTURBANCE NOW COMING ONSHORE OVER OR WILL CROSS CO WED AM. THIS
WILL BRING INCREASED CLOUDS AND WINDS ALOFT...WHICH WILL MITIGATE
FG FORMATION. HOWEVER...AT THIS POINT IT LOOKS LIKE THE DISTURBANCE
WILL BE TOO WEAK TO COUNTER THE LIGHT WINDS...SNOW COVER...AND
COLD AIR TRAPPED IN THE SAN LUIS VALLEY. HAVE ADDED A CONSERVATIVE
PERIOD OF FG TO THE KALS TAF FOR LATE TONIGHT...BUT THERE IS A
GREAT DEAL OF UNCERTAINTY ON THE EXTENT AND TIMING OF FG COVERAGE
FOR THE VALLEY. PERSISTENCE LOOKS LIKE THE BEST BET FOR THE
CURRENT FORECAST...SO WILL GO WITH CONTINUED FG FOR NOW.
NEXT CHALLENGE IS THE CHANCES FOR PRECIP AT KPUB AND KCOS TOMORROW.
A COLD FRONT WILL DROP THROUGH WED AM AFTER 12Z...AND BRING LOW
CHANCES OF PRECIP TO THE CO PLAINS AND I-25 CORRIDOR. THE CHANCES
FOR -SN OR -SNRA WILL BE GREATEST LATE MORNING AND EARLY
AFTERNOON...BUT AT THIS TIME WITH THE PROB LESS THAN 20 PERCENT
WILL LEAVE EXPLICIT MENTION OF PRECIP OUT OF THE FORECAST. ANY
PRECIP WILL BE LIGHT...WITH NO SN ACCUMS EXPECTED. SHOWERS SHOULD
END FROM N TO S BY LATE WED AFTERNOON OR 00Z.
ONLY SURE BET WILL BE PERSISTENT LIGHT SHSN OVER THE SAWATCH
RANGE...ESPECIALLY N OF COTTONWOOD PASS AND VC KLXV THROUGH
WED MORNING. WINDS WILL INCREASE AGAIN AFTER 06Z TONIGHT FOR
THE RIDGE TOPS...AND LIGHT TO MDT MT WAVE ACTIVITY IS AGAIN A
POSSIBILITY WED AM JUST E OF THE RANGES. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ROSE
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
941 AM MST TUE DEC 31 2013
.UPDATE...
ISSUED AT 940 AM MST TUE DEC 31 2013
UPDATED GRIDS/ZONES TO INCREASE POPS A BIT OVER LAKE COUNTY...WHERE
PERSISTENT SHSN CONTINUE...AND ADJUST AREAL SKY COVERAGE. ROSE
UPDATE ISSUED AT 746 AM MST TUE DEC 31 2013
BASED ON LATEST OBS EXTENDED THE LIFR FOG IN KALS UNTIL 16Z. VIS
SHOULD IMPROVE AFTER 16Z WITH LIFR CIGS BREAKING BY 17Z. -KT
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 516 AM MST TUE DEC 31 2013
NEXT SHORTWAVE WILL BE RIDING THROUGH NORTHWEST FLOW ALOFT INTO
NORTHWEST COLORADO LATE TONIGHT. AHEAD OF THIS SYSTEM TODAY SHOULD
BE A WARM DAY WITH TEMPERATURES CLIMBING INTO THE 50S. ALREADY
STARTING TO SEE SOME WAVE CLOUDINESS AND THESE WILL CONTINUE TO
THICKEN AND SPREAD EASTWARD AS MORE MOISTURE EVIDENT IN WV PICS
CONTINUES TO STREAM IN FROM THE NORTHWEST THIS MORNING. THIS WILL
SERVE TO CUT BACK ON MAX TEMPS A BIT THIS AFTERNOON IN SOME
PLACES...ESPECIALLY ALONG THE ARKANSAS RIVER VALLEY WHERE WINDS MAY
HAVE A HARDER TIME MIXING DOWN. HRRR DEPICTS THIS IN SFC T FIELDS
NICELY. OTHER AREA WHERE TEMPS WILL REALLY STRUGGLE WILL BE ACROSS
THE SAN LUIS VALLEY WHERE SNOW COVER HAS ALREADY DROPPED MAX TEMPS
DOWN TO AROUND 10 BELOW ZERO THIS MORNING. DEPENDING ON HOW QUICKLY
AND THICKLY HIGH CLOUDS SPREAD IN LATER THIS MORNING...TEMPERATURES
MAY STRUGGLE TO GET INTO THE MID/UPPER TEENS. HAVE CUT BACK ON MAX
TEMPS THERE CONSIDERABLY OVER GUIDANCE. MEANWHILE FOG IN THE SAN
LUIS VALLEY SHOULD THIN SOME AS HIGH CLOUDINESS MOVES IN THROUGH THE
MORNING...THEN DISSIPATE ENTIRELY BY 16Z. MEANWHILE...CENTRAL
MOUNTAINS WILL SEE OROGRAPHIC SNOW SHOWERS SPREAD IN DURING THE
MORNING...THEN DECREASE A BIT TOWARDS AFTERNOON. ANY ACCUMULATIONS LOOK
LIGHT AT THIS POINT...AND CONFINED MOSTLY TO THE HIGHER ELEVATIONS
OF THE SAWATCH AND MOSQUITO RANGES.
TONIGHT...SNOW SHOULD START TO RAMP UP ALONG THE CONTINENTAL DIVIDE
TOWARDS 06Z...WITH A FEW SNOW SHOWERS POSSIBLY SPREADING INTO THE
HIGHER PEAKS OF THE SANGRES TOWARDS 12Z. HEAVIEST ACCUMULATIONS
WILL STAY CONFINED TO THE CENTRAL MOUNTAINS WHERE ANOTHER 1 TO 3
INCHES WILL BE POSSIBLE OVERNIGHT. WESTERLY WINDS INTO THE LEE SIDE
SFC LOW WILL KEEP MIN TEMPS WARM ALONG THE LOWER EASTERN SLOPES OF
THE SE MTS. A COLD FRONT WILL DROP THROUGH THE SOUTHEAST PLAINS
AFTER 09Z BRINGING AN INCREASE IN NORTH WINDS TOWARDS DAWN. GFS AND
ECMWF APPEAR TO HAVE TRENDED TOWARDS A MORE AMPLIFIED SOLN WITH THE
UPPER TROF AS IT MOVES ACROSS SE CO TOWARDS MORNING...BUT FOR NOW
THINK ANY LIGHT PRECIP WILL HOLD OFF UNTIL AFTER 12Z. -KT
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 516 AM MST TUE DEC 31 2013
NOT MANY METEOROLOGICAL ADJUSTMENTS NEEDED DURING THE LONGER TERM
WITH PRIMARY CONCERNS CONTINUING TO BE POPS...GUSTY WINDS AT TIMES
AND TEMPERATURES.
RECENT LONGER TERM COMPUTER SIMULATIONS INDICATES THAT A COUPLE
OF UPPER DISTURBANCES WILL CROSS THE FORECAST DISTRICT DURING THE
LONGER TERM WITH THE INITIAL SYSTEM IMPACTING THE CWFA NEW YEARS
DAYS AND ANOTHER SYSTEM IMPACTING SOUTHERN COLORADO DURING THE
WEEKEND.
THEN GENERALLY DRY AND MILD TO WARM CONDITIONS SHOULD DEVELOP
OVER THE FORECAST DISTRICT FROM THURSDAY INTO FRIDAY AS DRY
NORTHWESTERLY UPPER FLOW IMPACTS SOUTHERN COLORADO.
A RETURN TO COOLER AND UNSETTLED CONDITIONS IS THEN ANTICIPATED
THIS WEEKEND AS ANOTHER UPPER DISTURBANCE IMPACTS THE FORECAST
DISTRICT. FINALLY...GUSTY WINDS WILL BE POSSIBLE OF MANY LOCATIONS
FROM WEDNESDAY INTO WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 516 AM MST TUE DEC 31 2013
LIFR CONDITIONS IN STRATUS/FOG WILL CONTINUE AT KALS (EVIDENT IN NOT
ONLY THE KALS SFC OB...BUT ALSO IN THE CDOT WEB CAMS AT ALAMOSA AND
VILLA GROVE) THIS MORNING. HOWEVER...AS HIGH CLOUDS SPREAD IN
TOWARDS 12-14Z...SUSPECT THAT VISIBILITIES WILL INCREASE AROUND THAT
TIME...WITH LIFR CONDITIONS COMING TO AN END BETWEEN 14-15Z. MAY
HAVE TO TWEAK THE KALS TAF FOR TIMING AS NEEDED THIS MORNING.
OTHERWISE...VFR CONDITIONS EXPECTED...WITH BOUTS OF MID-HIGH LEVEL
WAVE CLOUDINESS SPREADING IN ACROSS THE TAF SITES THROUGH THE DAY.
THE CENTRAL MOUNTAINS WILL SEE SOME SCATTERED SNOW SHOWERS WITH MTN
OBSCURATIONS AT TIMES TODAY. TONIGHT...A COLD FRONT WILL DROP
THROUGH KCOS AND KPUB BETWEEN 09Z-12Z BRINGING A WIND SHIFT FROM THE
NORTH TO NORTHWEST AT AROUND 10-20 KTS. MEANWHILE...INCREASING
CLOUDINESS AHEAD OF THE NEXT SYSTEM MOVING IN TONIGHT SHOULD PREVENT
FOG FROM REDEVELOPING ACROSS THE SAN LUIS VALLEY. CIGS AT THE TAF
SITES WILL LIKELY REMAIN VFR. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ROSE
AREA FORECAST DISCUSSION
NWS TAUNTON MA
523 PM EST TUE DEC 31 2013
.SYNOPSIS...
ARCTIC AIR WILL BE IN CONTROL FOR MOST OF THE WEEK...ESPECIALLY
FRIDAY INTO SATURDAY WITH THE POTENTIAL FOR BITTERLY COLD
TEMPERATURES. CONCERN CONTINUES FOR A DEVELOPING STORM OFF THE
EASTERN SEABOARD THURSDAY INTO FRIDAY...WITH THE POTENTIAL FOR
PLOWABLE SNOW AND STRONG WINDS FOR PORTIONS OF THE REGION ALONG
WITH POSSIBLE COASTAL FLOODING.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AFTERNOON UPDATE...
REGIONAL RADAR MOSAICS SHOWING NEXT AREA OF SNOW SHOWERS ACROSS
NY STATE. THESE SHOWERS HAD SOME LAKE ENHANCEMENT. WHILE THE
CLOUDS ASSOCIATED WITH A CLIPPER MOVING THROUGH THE GREAT LAKES
WERE ALREADY SPILLING OVER THE BERKSHIRES...IT IS EXPECTED THAT
LOW- LEVEL MOISTURE WILL BE VERY TOUGH TO COME BY EAST OF THE
BERKSHIRES. THUS THE SNOW SHOWERS SHOULD WEAKEN AS THEY MOVE
FARTHER EAST. LATEST RUNS OF THE HRRR AND RAP SEEM TO BE HANDLING
THIS WELL...SO WILL USE THEM TO HANDLE THE REST OF THIS AFTERNOON.
FOR THE REST OF TONIGHT...A COLD FRONT WILL BE FOLLOWED BY A
REINFORCING SHOT OF VERY COLD AIR. ONCE ALL THE SNOW SHOWERS END
THIS EVENING...DRY AND COLD WEATHER PREVAILS FOR THE REST OF
TONIGHT. EXPECTING A FEW MORE CLOUDS TONIGHT THAN LAST NIGHT...SO
HAVE MINIMUM TEMPERATURES SLIGHTLY HIGHER THAN WHAT WE SAW TUESDAY
MORNING. WINDS WILL BE SLIGHTLY HIGHER TONIGHT...RESULTING IN
WIND CHILL VALUES SIMILAR TO LAST NIGHT.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
CLOUDS INCREASE DURING THE DAY WEDNESDAY...WITH PREDOMINANTLY
OVERCAST SKIES EXPECTED FOR WEDNESDAY NIGHT. WITH A HIGH PRESSURE
CORE OVER SOUTHERN ONTARIO AND QUEBEC...THINKING WEDNESDAY WILL
REMAIN DRY.
DECENT OVERRUNNING COMBINED WITH A WEAK MID-LEVEL SHORTWAVE AND
SOME FRONTOGENESIS IN THE 925-850 MB LAYER SHOULD BE ENOUGH TO
GENERATE SOME LIGHT SNOW. ONSET TIMING COULD USE SOME
REFINEMENT...BUT CURRENTLY THINKING THE MAJORITY OF ANY SNOW
WEDNESDAY NIGHT WILL BE AFTER MIDNIGHT...AND POSSIBLY QUITE LATE
WEDNESDAY NIGHT ACROSS RI AND EASTERN MA.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...
* COASTAL STORM WITH SNOW...STRONG WINDS AND POSSIBLE COASTAL
EFFECTS THURSDAY INTO FRIDAY
* WELL BELOW NORMAL TEMPERATURES FOR FRIDAY AND SATURDAY
* ANOTHER POSSIBLE SYSTEM IMPACTING THE REGION SUNDAY NIGHT INTO
MONDAY
CONFIDENCE LEVEL...
MODERATE TO HIGH CONFIDENCE IN THE OVERALL FORECAST TREND WITH
THE SYSTEM THU INTO FRI...THEN HIGH PRES AND VERY COLD TEMPS INTO
THE WEEKEND. FURTHER OUT...CHANGING UPPER LEVEL PATTERN OVER THE
CENTRAL U.S. CAUSES TIMING ISSUES FOR ANOTHER LOW FROM SUN NIGHT
INTO TUE YIELDING LOW CONFIDENCE.
DETAILS...
THURSDAY INTO FRIDAY...
NOTING TWO PIECES OF UPPER LEVEL ENERGY...ONE MOVING OUT OF THE
CANADIAN ROCKIES AND A SECOND EXPECTED TO GATHER STRENGTH OVER THE
NORTHERN GULF OF MEXICO. EXPECT THESE TO DEVELOP LOW PRES MOVING
OFF THE OUTER BANKS OF NC LATE THU/THU NIGHT...THEN WILL TRACK
ABOUT 200 MILES S-SE OF NANTUCKET /SOUTH OF THE 40N/70W
BENCHMARK/. EVEN WITH THE LOW PASSING WELL S...STILL EXPECTING
QUITE A FEW HAZARDS DUE TO LONG E-NE FETCH BRINGING LL MOISTURE
WITH THE ARCTIC AIRMASS IN PLACE. EXPECTING AT LEAST MODERATE
SNOWFALL FOR MOST AREAS...STRONG WINDS CAUSING BLOWING AND
DRIFTING SNOW ALONG WITH BITTER COLD TEMPS. ALONG E FACING
BEACHES...WILL LIKELY SEE WIDESPREAD MINOR WITH POCKETS OF
MODERATE COASTAL FLOODING. DETAILS BELOW...
* MODELS...MOST OF THE MODEL SUITE IN RATHER GOOD AGREEMENT WITH THE
DEVELOPMENT OF THE LOW...OR EVEN SEVERAL WAVES OF LOW PRES WELL S
OF NEW ENGLAND...KEEPING SOME W-E PROGRESSION BUT HOLDING IN PLACE
THROUGH THIS TIMEFRAME. WITH THE HIGH SET UP OVER QUEBEC/N
MAINE...THIS KICKS UP THE ONSHORE FETCH OF LL MOISTURE. 00Z
ECMWF/12Z GFS ALONG WITH THEIR ENSEMBLES AND NOW...EVEN THE 12Z
UKMET...SETTING UP E-W SURFACE TROUGH. ALSO NOTING EXCELLENT 925-
850 HPA FGEN FORCING SETTING UP THU NIGHT ACROSS NE CT/RI/SE MA
WHICH WILL ONLY ENHANCE LIFT. STILL SOME SPREAD AMONGST THE GEFS
ENSEMBLE MEMBERS...THOUGH NOT QUITE AS MUCH AS SEEN IN EARLIER
RUNS. BEST AGREEMENT AND CONSISTENCY REMAINS WITH THE 00Z ECMWF/
12Z GFS AND THEIR ENSEMBLES. AVERAGE CONFIDENCE FORECAST.
* TEMPS...THERMAL PROFILES REMAIN MAINLY BELOW 0C. TEMPS START IN
THE LOWER-MID 30S ACROSS THE CAPE AND ISLANDS...BUT WILL DROP THU
NIGHT AND REMAIN COLD ON FRIDAY. TEMPS WILL RUN AT LEAST 10 TO 15
DEGREES BELOW NORMAL THROUGHOUT THIS EVENT...THEN WILL DROP EVEN
LOWER AS ANOTHER SHOT OF EVEN COLDER AIR WORKS IN DIRECTLY FROM
THE NORTH POLE. GUSTY N WINDS WILL CAUSE WIND CHILL VALUES TO
DROP BELOW -15F...SO WIND CHILL ADVISORIES MAY BE NEEDED FOR
CENTRAL AND WESTERN AREAS.
* SNOW...EXPECTING ALL SNOW FOR PTYPE WITH ARCTIC AIR IN PLACE ONLY
TURNING COLDER THU NIGHT AND FRI. H925 TEMPS RANGING BETWEEN -8C
TO -13C ACROSS THE AREA THU NIGHT THEN WILL DROP FURTHER FRI.
WITH DEEP LOW AND MID LEVEL MOISTURE ALONG WITH THE DEEP COLD
AIRMASS OVER THE REGION...EXPECTING HIGH SNOW TO WATER RATIOS ON
ORDER OF 15-20 TO ONE...YIELDING A POWDERY SNOW FOR MOST AREAS.
MAY BE A BIT LOWER ALONG THE IMMEDIATE E COAST WITH THE ONSHORE
WINDS. USED A BLEND OF THE PREVIOUS FORECAST AND GFS FOR QPF
FORECAST. LOOKS TO BE AROUND 0.3 TO 0.4 INCHES FOR MOST AREAS THU
NIGHT INTO EARLY FRI ALONE...WITH TOTAL OF 0.6 TO 0.8 INCHES
THROUGH THE EVENT. THEN...WITH THE NE WINDS BECOMING N...COULD SEE
MORE OCEAN EFFECT SNOWS LINGERING ALONG THE IMMEDIATE COAST MAINLY
OVER THE CAPE AND ISLANDS DURING FRIDAY. A BIT MORE CONFIDENCE ON
QPF AND SNOW TOTALS BUT STILL SOME TIME FOR ADJUSTMENTS IN TRACK
AND AMOUNTS.
* WIND...LARGE PRES GRADIENT DEVELOPS BETWEEN 1033 HPA HIGH OVER S
QUEBEC AND DEVELOPING LOW PRES WILL BRING INCREASING NE WINDS
ESPECIALLY ALONG THE E COAST. H925 JET AT 40-45 KT MOVES INTO SE
MA THU NIGHT INTO EARLY FRI...THEN BACKS TO N AS THE LOW PUSHES
OFFSHORE. EXPECT GUSTS TO REACH 35-40 KT...HIGHEST ON THE OUTER
CAPE AND NANTUCKET. WILL SEE CONSIDERABLE BLOWING AND DRIFTING
SNOW WITH THESE GUSTS WHICH WILL REDUCE VSBYS...ESPECIALLY ACROSS
COASTAL AREAS.
* COASTAL FLOODING...SEE DISCUSSION BELOW.
FRIDAY NIGHT THROUGH SUNDAY...
N-S ELONGATED HIGH PRES WILL BUILD OUT OF THE GREAT LAKES TO THE
SE U.S. WITH N-NW WINDS IN PLACE BRINGING ANOTHER SHOT OF ARCTIC
AIR TO THE REGION. COULD STILL SEE OCEAN EFFECT SNOWFALL OVER THE
MID AND OUTER CAPE AS WELL AS NANTUCKET FOR AT LEAST THE EARLY
PORTION OF FRI NIGHT. AS THE HIGH SETTLES OVER THE REGION...WINDS
WILL DIMINISH BUT IT WILL BE BITTERLY COLD. THE RELATIVELY MILDER
SPOTS WILL BE CAPE COD AND THE ISLANDS DUE TO THE WARMER OCEAN
WATERS. EXPECTING OVERNIGHT LOWS FRI NIGHT MAINLY FROM ZERO TO 10
BELOW FOR MOST INLAND AREAS EVEN INTO INTERIOR SE MA/NW RI AND N
CT...POSSIBLY EVEN LOWER ACROSS THE HIGHER TERRAIN OF SW NH/NW MA.
IT MIGHT EVEN TOUCH ZERO IN BOSTON...WHICH LAST OCCURRED JANUARY
24 2011 WHEN IT DROPPED TO -2. EVEN WITH LIGHT WINDS...THERE WILL
BE ENOUGH FOR WIND CHILL VALUES TO DROP TO -15F TO -20F /S TO N/.
MAY NEED A WIND CHILL ADVISORY FRIDAY NIGHT...INCLUDING THE CITY
OF BOSTON.
RIDGE MOVES OFFSHORE DURING SAT SO EXPECT DRY CONDITIONS WITH HIGHS
IN THE MID TEENS AND 20S INLAND TO AROUND 30 ACROSS CAPE COD AND THE
ISLANDS.
EXPECT RETURN SW FLOW TO KICK IN FOR SUNDAY BRINGING STRONG WARM AIR
ADVECTION TO THE REGION. HIGHS WILL RANGE FROM 30-35 ACROSS S NH TO
THE MID 40S ON THE CAPE AND ISLANDS. MODELS SIGNALING SOME POSSIBLE
PRECIP WORKING IN WITH THIS FLOW DURING THE AFTERNOON WITH A MIX OF
RAIN AND/OR SNOW SHOWERS.
SUNDAY NIGHT INTO TUESDAY...
LARGE MODEL DIFFERENCES CONTINUE DURING THIS TIMEFRAME. WEAK LOW
PRES MOVES NE ACROSS THE OHIO VALLEY TOWARD THE REGION SUN NIGHT
INTO MONDAY. HOWEVER...TIMING DIFFERENCES WITH THE MOVEMENT OF
THIS LOW BRINGS A LOT OF UNCERTAINTY AS TO PRECIP AMOUNT AND
TYPES. FOR NOW...LOOKS LIKE LOW SHOULD MOVE EITHER RIGHT ACROSS OR
TO THE W OF THE REGION...WHICH COULD MEAN SOME MIXED PRECIP WELL
INLAND AS COLD AIR TRIES TO HOLD IN PLACE. KEPT CHANCE POPS GOING
THROUGH MONDAY... THEN SHOULD START TAPERING OFF MON NIGHT.
FOR NOW...CARRIED MAINLY DRY POPS FOR TUESDAY...EXCEPT FOR SOME
POSSIBLE SNOW SHOWERS OVER THE CAPE AND ISLANDS WITH YET ANOTHER
SHOT OF COLD AIR.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /TODAY THROUGH WEDNESDAY AFTERNOON/...
THROUGH TONIGHT...HIGH CONFIDENCE VFR CONDITIONS MOST LOCATIONS.
THE EXCEPTION WILL BE BRIEFLY SCATTERED MVFR CIGS/VSBYS LATE THIS
AFTERNOON AND EARLY EVENING ACROSS THE WESTERN HALF OF SOUTHERN
NEW ENGLAND IN SNOW SHOWERS.
WEDNESDAY...HIGH CONFIDENCE VFR.
WEDNESDAY NIGHT...HIGH CONFIDENCE IN TRENDS...MODERATE CONFIDENCE
IN TIMING. CONDITIONS LOWERING TO MVFR IN SNOW...MAINLY AFTER
MIDNIGHT.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF. LOW PROBABILITY OF BRIEF MVFR
CONDITIONS LATE THIS AFTERNOON/EARLY EVENING.
OUTLOOK...THURSDAY THROUGH SUNDAY...MODERATE CONFIDENCE.
THURSDAY...IFR CIGS/VSBYS IN SNOW. LOCAL LIFR CONDITIONS LIKELY.
EAST TO NORTHEAST WINDS WITH GUSTS 30 TO 40 KT ALONG THE
COAST...HIGHEST ACROSS CAPE COD AND THE ISLANDS. SIGNIFICANT SNOW
ACCUMULATIONS LIKELY.
FRIDAY...IFR CONDITIONS IN SNOW FOR MOST AREAS THROUGH THE DAY.
CONDITIONS IMPROVE TO VFR FRIDAY AFTERNOON ACROSS WESTERN NEW
ENGLAND. BRIEF WIND GUSTS UP TO 40 KT POSSIBLE WITH THE INITIAL
SURGE OF ARCTIC AIR BEHIND DEPARTING LOW PRESSURE. EXPECT VFR FRIDAY
NIGHT...THOUGH COULD SEE MVFR-IFR IN THE EVENING ACROSS CAPE COD AND
NANTUCKET.
SATURDAY...VFR.
SUNDAY...VFR TO START...THEN AREAS OF MVFR FROM SW-NE DURING THE
AFTERNOON/NIGHT WITH RAIN AND/OR SNOW BY NIGHTFALL.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /TODAY THROUGH WEDNESDAY NIGHT/...HIGH CONFIDENCE.
TONIGHT...A COLD FRONT CROSSES THE WATERS WITH A ROUND OF STRONG
WESTERLY WIND GUSTS UP TO 30 KT. SMALL CRAFT ADVISORIES POSTED
FOR MOST WATERS ALONG WITH POTENTIAL FOR LIGHT FREEZING SPRAY.
THERE COULD BE A BRIEF PERIOD OF GALE FORCE GUSTS BETWEEN 4 PM AND
9 PM. DECIDED TO NOT ISSUE A GALE WARNING AS GUSTS ARE MARGINAL
AND IT IS FOR A RELATIVELY SHORT PERIOD OF TIME.
WEDNESDAY...SMALL CRAFT ADVISORY WINDS/SEAS EARLY SHOULD
TEMPORARILY DIMINISH BELOW CRITERIA ACROSS ALL WATERS BY MID
AFTERNOON AS HIGH PRESSURE MOVES ACROSS THE WATERS.
WEDNESDAY NIGHT...RELATIVELY LIGHT WINDS AND SEAS EXPECTED. WINDS
TURN EAST AHEAD OF A NOREASTER MOVING SOUTH OF THE WATERS. SEAS
BEGIN TO REBUILD LATE WEDNESDAY NIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...MODERATE CONFIDENCE.
THURSDAY...E-NE WINDS INCREASE DURING THE DAY...WITH GUSTS TO 35-40
KT DEVELOPING IN THE EVENING. SEAS BUILDING UP TO 10-18 FT HIGHEST
ON THE OUTER WATERS THU NIGHT. GALE WARNINGS WILL BE NEEDED.
FRIDAY...NE WINDS SHIFT TO N DURING THE DAY...WITH GUSTS OF 30-45
KNOTS. NW WINDS DIMINISH FRI NIGHT. SEAS WILL BE 15 TO 20 FEET ON
THE EASTERN WATERS AND 10 TO 15 FEET ON THE SOUTHERN WATERS.
SATURDAY...EXPECT WINDS AND SEAS DIMINISH...THOUGH WILL REMAIN IN
SMALL CRAFT CRITERIA.
SUNDAY...WINDS AND SEAS BELOW SMALL CRAFT CRITERIA.
&&
.TIDES/COASTAL FLOODING...
ECMWF AND GFS MODELS ALONG WITH THEIR ENSEMBLE MEMBERS HAVE TRENDED
TOWARD A MORE PROGRESSIVE/FURTHER SOUTHEAST TRACK WITH THE COASTAL
STORM THU-FRI. THIS REDUCES THE RISK OF MAJOR COASTAL FLOODING FOR
THE FRIDAY MIDDAY HIGH TIDE ALONG THE MA E COAST. NEVERTHELESS...THE
COMBINATION OF HIGH ASTRONOMICAL TIDES AND RELATIVELY LONG
DURATION AND FETCH OF NORTHEASTERLY WINDS SETS THE STAGE FOR
MINOR TO MODERATE COASTAL FLOODING FOR MULTIPLE HIGH TIDE CYCLES.
USING BOSTON AS AN INDEX...NOTE THAT ASTRONOMICAL HIGH TIDES ARE
VERY HIGH WITH 12.2 FEET MEAN LOWER LOW WATER AT BOSTON THU AND
FRI...AT 11:22 AM AND 12:15 PM RESPECTFULLY. THERE ALSO IS A 10.9
FOOT HIGH TIDE AT BOSTON THU NIGHT AROUND MIDNIGHT. AS USUAL IN
THESE SITUATIONS...HAVE GONE ABOVE BOTH THE ETSS AND ESTOFS
GUIDANCE BASED ON SYNOPTIC PATTERN RECOGNITION. BELIEVE ENOUGH
GRADIENT AND FETCH TO SUPPORT A STORM SURGE OF .5 TO
.75 FT THU MIDDAY...INCREASING TO 1.0 TO 2.0 FT FOR BOTH THE THU
NIGHT AND FRI MIDDAY TIDES...HIGHEST S OF BOSTON. THE SURGE MAY
ACTUALLY MAX OUT 2 TO 3 FT S OF BOSTON FRI MORNING...BUT DURING
THE LOW TIDE CYCLE. SEAS JUST OFFSHORE ARE EXPECTED TO REACH ABOUT
15 FT DURING THE THU NIGHT HIGH TIDE AND 15 TO 20 FT AT THE TIME
OF THE FRI MIDDAY HIGH TIDE. THE FRIDAY MIDDAY SEAS WILL CONTAIN
LONGER PERIOD SWELLS THAT BRING MORE ENERGY TO THE SHORE.
THIS IS ALL LIKELY TO RESULT IN MINOR COASTAL FLOODING FOR THE THU
MIDDAY HIGH TIDE AND MINOR TO MODERATE COASTAL FLOODING FOR THE
THU NIGHT HIGH TIDE. AT THIS TIME FOR THE FRI MIDDAY HIGH
TIDE...WE ARE PROJECTING MINOR TO ISOLATED MODERATE COASTAL
FLOODING N OF BOSTON AND AREAS OF MODERATE COASTAL FLOODING S OF
BOSTON. THERE REMAINS A RISK...ALBEIT LOOKING LOWER THAN 24 HOURS
AGO...OF POCKETS OF MODERATE TO MAJOR COASTAL FLOODING HULL THROUGH
SANDWICH AND NANTUCKET...ESPECIALLY IF THE STORM SHOULD END UP
BEING JUST A TAD SLOWER PULLING AWAY FROM OUR COASTLINE.
ALL VULNERABLE MA E FACING SHORELINES WILL HAVE A RISK OF SOME
BEACH EROSION GIVEN THE HIGH WATER LEVELS AND WAVE ACTION OVER
SUCCESSIVE TIDES. THE AREAS OF COASTLINE PRONE TO MORE SIGNIFICANT
BEACH EROSION INCLUDE THE PLYMOUTH COUNTY COAST...N SIDE OF THE
CAPE INCLUDING SANDWICH...THE OUTER CAPE OCEAN SIDE AND THE E SIDE
OF NANTUCKET.
NOT EXPECTING ANY COASTAL FLOODING PROBLEMS ALONG THE SOUTH COAST
GIVEN WIND DIRECTION AND EXPECTED TRACK OF THE STORM.
&&
.CLIMATE...
RECORD MINIMUM HIGH TEMPERATURES FOR JANUARY 3RD...
BOSTON 7 /1904/
HARTFORD 7 /1981/
PROVIDENCE 10 /1918/
WORCESTER 4 /1904/
RECORD LOW TEMPERATURES FOR JANUARY 4TH...
BOSTON -4 /1981/
HARTFORD -7 /1981/
PROVIDENCE -9 /1981/
WORCESTER -8 /1981/
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR ANZ231>235-
237.
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 4 AM EST
WEDNESDAY FOR ANZ230.
SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR ANZ250-251.
SMALL CRAFT ADVISORY UNTIL 4 PM EST WEDNESDAY FOR ANZ254>256.
&&
$$
SYNOPSIS...BELK/EVT
NEAR TERM...BELK
SHORT TERM...BELK
LONG TERM...EVT
AVIATION...BELK/EVT
MARINE...BELK/EVT
TIDES/COASTAL FLOODING...THOMPSON
CLIMATE...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
453 PM EST TUE DEC 31 2013
.SYNOPSIS...
ARCTIC AIR WILL BE IN CONTROL FOR MOST OF THE WEEK...ESPECIALLY
FRIDAY INTO SATURDAY WITH THE POTENTIAL FOR BITTERLY COLD
TEMPERATURES. CONCERN CONTINUES FOR A DEVELOPING STORM OFF THE
EASTERN SEABOARD THURSDAY INTO FRIDAY...WITH THE POTENTIAL FOR
PLOWABLE SNOW AND STRONG WINDS FOR PORTIONS OF THE REGION ALONG
WITH POSSIBLE COASTAL FLOODING.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AFTERNOON UPDATE...
REGIONAL RADAR MOSAICS SHOWING NEXT AREA OF SNOW SHOWERS ACROSS
NY STATE. THESE SHOWERS HAD SOME LAKE ENHANCEMENT. WHILE THE
CLOUDS ASSOCIATED WITH A CLIPPER MOVING THROUGH THE GREAT LAKES
WERE ALREADY SPILLING OVER THE BERKSHIRES...IT IS EXPECTED THAT
LOW- LEVEL MOISTURE WILL BE VERY TOUGH TO COME BY EAST OF THE
BERKSHIRES. THUS THE SNOW SHOWERS SHOULD WEAKEN AS THEY MOVE
FARTHER EAST. LATEST RUNS OF THE HRRR AND RAP SEEM TO BE HANDLING
THIS WELL...SO WILL USE THEM TO HANDLE THE REST OF THIS AFTERNOON.
FOR THE REST OF TONIGHT...A COLD FRONT WILL BE FOLLOWED BY A
REINFORCING SHOT OF VERY COLD AIR. ONCE ALL THE SNOW SHOWERS END
THIS EVENING...DRY AND COLD WEATHER PREVAILS FOR THE REST OF
TONIGHT. EXPECTING A FEW MORE CLOUDS TONIGHT THAN LAST NIGHT...SO
HAVE MINIMUM TEMPERATURES SLIGHTLY HIGHER THAN WHAT WE SAW TUESDAY
MORNING. WINDS WILL BE SLIGHTLY HIGHER TONIGHT...RESULTING IN
WIND CHILL VALUES SIMILAR TO LAST NIGHT.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
CLOUDS INCREASE DURING THE DAY WEDNESDAY...WITH PREDOMINANTLY
OVERCAST SKIES EXPECTED FOR WEDNESDAY NIGHT. WITH A HIGH PRESSURE
CORE OVER SOUTHERN ONTARIO AND QUEBEC...THINKING WEDNESDAY WILL
REMAIN DRY.
DECENT OVERRUNNING COMBINED WITH A WEAK MID-LEVEL SHORTWAVE AND
SOME FRONTOGENESIS IN THE 925-850 MB LAYER SHOULD BE ENOUGH TO
GENERATE SOME LIGHT SNOW. ONSET TIMING COULD USE SOME
REFINEMENT...BUT CURRENTLY THINKING THE MAJORITY OF ANY SNOW
WEDNESDAY NIGHT WILL BE AFTER MIDNIGHT...AND POSSIBLY QUITE LATE
WEDNESDAY NIGHT ACROSS RI AND EASTERN MA.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...
* COASTAL STORM WITH SNOW...STRONG WINDS AND POSSIBLE COASTAL
EFFECTS THURSDAY INTO FRIDAY
* WELL BELOW NORMAL TEMPERATURES FOR FRIDAY AND SATURDAY
* ANOTHER POSSIBLE SYSTEM IMPACTING THE REGION SUNDAY NIGHT INTO
MONDAY
CONFIDENCE LEVEL...
MODERATE TO HIGH CONFIDENCE IN THE OVERALL FORECAST TREND WITH
THE SYSTEM THU INTO FRI...THEN HIGH PRES AND VERY COLD TEMPS INTO
THE WEEKEND. FURTHER OUT...CHANGING UPPER LEVEL PATTERN OVER THE
CENTRAL U.S. CAUSES TIMING ISSUES FOR ANOTHER LOW FROM SUN NIGHT
INTO TUE YIELDING LOW CONFIDENCE.
DETAILS...
THURSDAY INTO FRIDAY...
NOTING TWO PIECES OF UPPER LEVEL ENERGY...ONE MOVING OUT OF THE
CANADIAN ROCKIES AND A SECOND EXPECTED TO GATHER STRENGTH OVER THE
NORTHERN GULF OF MEXICO. EXPECT THESE TO DEVELOP LOW PRES MOVING
OFF THE OUTER BANKS OF NC LATE THU/THU NIGHT...THEN WILL TRACK
ABOUT 200 MILES S-SE OF NANTUCKET /SOUTH OF THE 40N/70W
BENCHMARK/. EVEN WITH THE LOW PASSING WELL S...STILL EXPECTING
QUITE A FEW HAZARDS DUE TO LONG E-NE FETCH BRINGING LL MOISTURE
WITH THE ARCTIC AIRMASS IN PLACE. EXPECTING AT LEAST MODERATE
SNOWFALL FOR MOST AREAS...STRONG WINDS CAUSING BLOWING AND
DRIFTING SNOW ALONG WITH BITTER COLD TEMPS. ALONG E FACING
BEACHES...WILL LIKELY SEE WIDESPREAD MINOR WITH POCKETS OF
MODERATE COASTAL FLOODING. DETAILS BELOW...
* MODELS...MOST OF THE MODEL SUITE IN RATHER GOOD AGREEMENT WITH THE
DEVELOPMENT OF THE LOW...OR EVEN SEVERAL WAVES OF LOW PRES WELL S
OF NEW ENGLAND...KEEPING SOME W-E PROGRESSION BUT HOLDING IN PLACE
THROUGH THIS TIMEFRAME. WITH THE HIGH SET UP OVER QUEBEC/N
MAINE...THIS KICKS UP THE ONSHORE FETCH OF LL MOISTURE. 00Z
ECMWF/12Z GFS ALONG WITH THEIR ENSEMBLES AND NOW...EVEN THE 12Z
UKMET...SETTING UP E-W SURFACE TROUGH. ALSO NOTING EXCELLENT 925-
850 HPA FGEN FORCING SETTING UP THU NIGHT ACROSS NE CT/RI/SE MA
WHICH WILL ONLY ENHANCE LIFT. STILL SOME SPREAD AMONGST THE GEFS
ENSEMBLE MEMBERS...THOUGH NOT QUITE AS MUCH AS SEEN IN EARLIER
RUNS. BEST AGREEMENT AND CONSISTENCY REMAINS WITH THE 00Z ECMWF/
12Z GFS AND THEIR ENSEMBLES. AVERAGE CONFIDENCE FORECAST.
* TEMPS...THERMAL PROFILES REMAIN MAINLY BELOW 0C. TEMPS START IN
THE LOWER-MID 30S ACROSS THE CAPE AND ISLANDS...BUT WILL DROP THU
NIGHT AND REMAIN COLD ON FRIDAY. TEMPS WILL RUN AT LEAST 10 TO 15
DEGREES BELOW NORMAL THROUGHOUT THIS EVENT...THEN WILL DROP EVEN
LOWER AS ANOTHER SHOT OF EVEN COLDER AIR WORKS IN DIRECTLY FROM
THE NORTH POLE. GUSTY N WINDS WILL CAUSE WIND CHILL VALUES TO
DROP BELOW -15F...SO WIND CHILL ADVISORIES MAY BE NEEDED FOR
CENTRAL AND WESTERN AREAS.
* SNOW...EXPECTING ALL SNOW FOR PTYPE WITH ARCTIC AIR IN PLACE ONLY
TURNING COLDER THU NIGHT AND FRI. H925 TEMPS RANGING BETWEEN -8C
TO -13C ACROSS THE AREA THU NIGHT THEN WILL DROP FURTHER FRI.
WITH DEEP LOW AND MID LEVEL MOISTURE ALONG WITH THE DEEP COLD
AIRMASS OVER THE REGION...EXPECTING HIGH SNOW TO WATER RATIOS ON
ORDER OF 15-20 TO ONE...YIELDING A POWDERY SNOW FOR MOST AREAS.
MAY BE A BIT LOWER ALONG THE IMMEDIATE E COAST WITH THE ONSHORE
WINDS. USED A BLEND OF THE PREVIOUS FORECAST AND GFS FOR QPF
FORECAST. LOOKS TO BE AROUND 0.3 TO 0.4 INCHES FOR MOST AREAS THU
NIGHT INTO EARLY FRI ALONE...WITH TOTAL OF 0.6 TO 0.8 INCHES
THROUGH THE EVENT. THEN...WITH THE NE WINDS BECOMING N...COULD SEE
MORE OCEAN EFFECT SNOWS LINGERING ALONG THE IMMEDIATE COAST MAINLY
OVER THE CAPE AND ISLANDS DURING FRIDAY. A BIT MORE CONFIDENCE ON
QPF AND SNOW TOTALS BUT STILL SOME TIME FOR ADJUSTMENTS IN TRACK
AND AMOUNTS.
* WIND...LARGE PRES GRADIENT DEVELOPS BETWEEN 1033 HPA HIGH OVER S
QUEBEC AND DEVELOPING LOW PRES WILL BRING INCREASING NE WINDS
ESPECIALLY ALONG THE E COAST. H925 JET AT 40-45 KT MOVES INTO SE
MA THU NIGHT INTO EARLY FRI...THEN BACKS TO N AS THE LOW PUSHES
OFFSHORE. EXPECT GUSTS TO REACH 35-40 KT...HIGHEST ON THE OUTER
CAPE AND NANTUCKET. WILL SEE CONSIDERABLE BLOWING AND DRIFTING
SNOW WITH THESE GUSTS WHICH WILL REDUCE VSBYS...ESPECIALLY ACROSS
COASTAL AREAS.
* COASTAL FLOODING...SEE DISCUSSION BELOW.
FRIDAY NIGHT THROUGH SUNDAY...
N-S ELONGATED HIGH PRES WILL BUILD OUT OF THE GREAT LAKES TO THE
SE U.S. WITH N-NW WINDS IN PLACE BRINGING ANOTHER SHOT OF ARCTIC
AIR TO THE REGION. COULD STILL SEE OCEAN EFFECT SNOWFALL OVER THE
MID AND OUTER CAPE AS WELL AS NANTUCKET FOR AT LEAST THE EARLY
PORTION OF FRI NIGHT. AS THE HIGH SETTLES OVER THE REGION...WINDS
WILL DIMINISH BUT IT WILL BE BITTERLY COLD. THE RELATIVELY MILDER
SPOTS WILL BE CAPE COD AND THE ISLANDS DUE TO THE WARMER OCEAN
WATERS. EXPECTING OVERNIGHT LOWS FRI NIGHT MAINLY FROM ZERO TO 10
BELOW FOR MOST INLAND AREAS EVEN INTO INTERIOR SE MA/NW RI AND N
CT...POSSIBLY EVEN LOWER ACROSS THE HIGHER TERRAIN OF SW NH/NW MA.
IT MIGHT EVEN TOUCH ZERO IN BOSTON...WHICH LAST OCCURRED JANUARY
24 2011 WHEN IT DROPPED TO -2. EVEN WITH LIGHT WINDS...THERE WILL
BE ENOUGH FOR WIND CHILL VALUES TO DROP TO -15F TO -20F /S TO N/.
MAY NEED A WIND CHILL ADVISORY FRIDAY NIGHT...INCLUDING THE CITY
OF BOSTON.
RIDGE MOVES OFFSHORE DURING SAT SO EXPECT DRY CONDITIONS WITH HIGHS
IN THE MID TEENS AND 20S INLAND TO AROUND 30 ACROSS CAPE COD AND THE
ISLANDS.
EXPECT RETURN SW FLOW TO KICK IN FOR SUNDAY BRINGING STRONG WARM AIR
ADVECTION TO THE REGION. HIGHS WILL RANGE FROM 30-35 ACROSS S NH TO
THE MID 40S ON THE CAPE AND ISLANDS. MODELS SIGNALING SOME POSSIBLE
PRECIP WORKING IN WITH THIS FLOW DURING THE AFTERNOON WITH A MIX OF
RAIN AND/OR SNOW SHOWERS.
SUNDAY NIGHT INTO TUESDAY...
LARGE MODEL DIFFERENCES CONTINUE DURING THIS TIMEFRAME. WEAK LOW
PRES MOVES NE ACROSS THE OHIO VALLEY TOWARD THE REGION SUN NIGHT
INTO MONDAY. HOWEVER...TIMING DIFFERENCES WITH THE MOVEMENT OF
THIS LOW BRINGS A LOT OF UNCERTAINTY AS TO PRECIP AMOUNT AND
TYPES. FOR NOW...LOOKS LIKE LOW SHOULD MOVE EITHER RIGHT ACROSS OR
TO THE W OF THE REGION...WHICH COULD MEAN SOME MIXED PRECIP WELL
INLAND AS COLD AIR TRIES TO HOLD IN PLACE. KEPT CHANCE POPS GOING
THROUGH MONDAY... THEN SHOULD START TAPERING OFF MON NIGHT.
FOR NOW...CARRIED MAINLY DRY POPS FOR TUESDAY...EXCEPT FOR SOME
POSSIBLE SNOW SHOWERS OVER THE CAPE AND ISLANDS WITH YET ANOTHER
SHOT OF COLD AIR.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /TODAY THROUGH WEDNESDAY AFTERNOON/...
THROUGH TONIGHT...HIGH CONFIDENCE VFR CONDITIONS MOST LOCATIONS.
THE EXCEPTION WILL BE BRIEFLY SCATTERED MVFR CIGS/VSBYS LATE THIS
AFTERNOON AND EARLY EVENING ACROSS THE WESTERN HALF OF SOUTHERN
NEW ENGLAND IN SNOW SHOWERS.
WEDNESDAY...HIGH CONFIDENCE VFR.
WEDNESDAY NIGHT...HIGH CONFIDENCE IN TRENDS...MODERATE CONFIDENCE
IN TIMING. CONDITIONS LOWERING TO MVFR IN SNOW...MAINLY AFTER
MIDNIGHT.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF. LOW PROBABILITY OF BRIEF MVFR
CONDITIONS LATE THIS AFTERNOON/EARLY EVENING.
OUTLOOK...THURSDAY THROUGH SUNDAY...MODERATE CONFIDENCE.
THURSDAY...IFR CIGS/VSBYS IN SNOW. LOCAL LIFR CONDITIONS LIKELY.
EAST TO NORTHEAST WINDS WITH GUSTS 30 TO 40 KT ALONG THE
COAST...HIGHEST ACROSS CAPE COD AND THE ISLANDS. SIGNIFICANT SNOW
ACCUMULATIONS LIKELY.
FRIDAY...IFR CONDITIONS IN SNOW FOR MOST AREAS THROUGH THE DAY.
CONDITIONS IMPROVE TO VFR FRIDAY AFTERNOON ACROSS WESTERN NEW
ENGLAND. BRIEF WIND GUSTS UP TO 40 KT POSSIBLE WITH THE INITIAL
SURGE OF ARCTIC AIR BEHIND DEPARTING LOW PRESSURE. EXPECT VFR FRIDAY
NIGHT...THOUGH COULD SEE MVFR-IFR IN THE EVENING ACROSS CAPE COD AND
NANTUCKET.
SATURDAY...VFR.
SUNDAY...VFR TO START...THEN AREAS OF MVFR FROM SW-NE DURING THE
AFTERNOON/NIGHT WITH RAIN AND/OR SNOW BY NIGHTFALL.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /TODAY THROUGH WEDNESDAY NIGHT/...HIGH CONFIDENCE.
TONIGHT...A COLD FRONT CROSSES THE WATERS WITH A ROUND OF STRONG
WESTERLY WIND GUSTS UP TO 30 KT. SMALL CRAFT ADVISORIES POSTED
FOR MOST WATERS ALONG WITH POTENTIAL FOR LIGHT FREEZING SPRAY.
THERE COULD BE A BRIEF PERIOD OF GALE FORCE GUSTS BETWEEN 4 PM AND
9 PM. DECIDED TO NOT ISSUE A GALE WARNING AS GUSTS ARE MARGINAL
AND IT IS FOR A RELATIVELY SHORT PERIOD OF TIME.
WEDNESDAY...SMALL CRAFT ADVISORY WINDS/SEAS EARLY SHOULD
TEMPORARILY DIMINISH BELOW CRITERIA ACROSS ALL WATERS BY MID
AFTERNOON AS HIGH PRESSURE MOVES ACROSS THE WATERS.
WEDNESDAY NIGHT...RELATIVELY LIGHT WINDS AND SEAS EXPECTED. WINDS
TURN EAST AHEAD OF A NOREASTER MOVING SOUTH OF THE WATERS. SEAS
BEGIN TO REBUILD LATE WEDNESDAY NIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...MODERATE CONFIDENCE.
THURSDAY...E-NE WINDS INCREASE DURING THE DAY...WITH GUSTS TO 35-40
KT DEVELOPING IN THE EVENING. SEAS BUILDING UP TO 10-18 FT HIGHEST
ON THE OUTER WATERS THU NIGHT. GALE WARNINGS WILL BE NEEDED.
FRIDAY...NE WINDS SHIFT TO N DURING THE DAY...WITH GUSTS OF 30-45
KNOTS. NW WINDS DIMINISH FRI NIGHT. SEAS WILL BE 15 TO 20 FEET ON
THE EASTERN WATERS AND 10 TO 15 FEET ON THE SOUTHERN WATERS.
SATURDAY...EXPECT WINDS AND SEAS DIMINISH...THOUGH WILL REMAIN IN
SMALL CRAFT CRITERIA.
SUNDAY...WINDS AND SEAS BELOW SMALL CRAFT CRITERIA.
&&
.TIDES/COASTAL FLOODING...
LATEST ECMWF MODEL AND ITS ENSEMBLES HAS TRENDED MORE TOWARDS OTHER
GUIDANCE IN SHOWING A MORE PROGRESSIVE/FURTHER SOUTHEAST TRACK WITH
COASTAL STORM THU-FRI.
NONETHELESS...ASTRONOMICAL HIGH TIDES ARE VERY HIGH WITH 12.2 FEET
AT BOSTON THU AND FRI...AT 11:22 AM AND 12:15 PM RESPECTFULLY.
THERE ALSO IS A 10.9 FOOT HIGH TIDE THU NIGHT AROUND MIDNIGHT.
THEREFORE...EXPECT WIDESPREAD MINOR WITH THE POTENTIAL FOR POCKETS
OF MODERATE COASTAL FLOODING DURING THESE 3 HIGH TIDE CYCLES ALONG
THE EASTERN MA COAST. ANOTHER CONCERN WILL BE FOR BEACH EROSION IN
THIS REGION.
NOT EXPECTING ANY COASTAL FLOODING PROBLEMS ALONG THE SOUTH COAST
GIVEN WIND DIRECTION AND EXPECTED TRACK OF THE STORM.
&&
.CLIMATE...
RECORD MINIMUM HIGH TEMPERATURES FOR JANUARY 3RD...
BOSTON 7 /1904/
HARTFORD 7 /1981/
PROVIDENCE 10 /1918/
WORCESTER 4 /1904/
RECORD LOW TEMPERATURES FOR JANUARY 4TH...
BOSTON -4 /1981/
HARTFORD -7 /1981/
PROVIDENCE -9 /1981/
WORCESTER -8 /1981/
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR ANZ231>235-
237.
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 4 AM EST
WEDNESDAY FOR ANZ230.
SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR ANZ250-251.
SMALL CRAFT ADVISORY UNTIL 4 PM EST WEDNESDAY FOR ANZ254>256.
&&
$$
SYNOPSIS...BELK/EVT
NEAR TERM...BELK
SHORT TERM...BELK
LONG TERM...EVT
AVIATION...BELK/EVT
MARINE...BELK/EVT
TIDES/COASTAL FLOODING...STAFF
CLIMATE...STAFF
AREA FORECAST DISCUSSION
NWS TAUNTON MA
226 PM EST TUE DEC 31 2013
.SYNOPSIS...
ARCTIC AIR WILL BE IN CONTROL FOR MOST OF THE WEEK...ESPECIALLY
FRI INTO SAT WITH THE POTENTIAL FOR BITTERLY COLD TEMPS. THE OTHER
MAIN CONCERN WILL BE A DEVELOPING COASTAL STORM THAT WILL BRING
THE POTENTIAL FOR SIGNIFICANT SNOW/STRONG WINDS AND COASTAL
FLOODING TO PORTIONS OF THE REGION THU INTO FRI.
&&
.NEAR TERM /THROUGH TONIGHT/...
230 PM UPDATE...REGIONAL RADAR MOSAICS SHOWING NEXT AREA OF SNOW
SHOWERS ACROSS NY STATE. THESE SHOWERS HAD SOME LAKE ENHANCEMENT.
WHILE THE CLOUDS ASSOCIATED WITH A CLIPPER MOVING THROUGH THE
GREAT LAKES WERE ALREADY SPILLING OVER THE BERKSHIRES...IT IS
EXPECTED THAT LOW-LEVEL MOISTURE WILL BE VERY TOUGH TO COME BY
EAST OF THE BERKSHIRES. THUS THE SNOW SHOWERS SHOULD WEAKEN AS
THEY MOVE FARTHER EAST. LATEST RUNS OF THE HRRR AND RAP SEEM TO BE
HANDLING THIS WELL...SO WILL USE THEM TO HANDLE THE REST OF THIS
AFTERNOON.
FOR THE REST OF TONIGHT...A COLD FRONT WILL BE FOLLOWED BY A
REINFORCING SHOT OF VERY COLD AIR. ONCE ALL THE SNOW SHOWERS END
THIS EVENING...DRY AND COLD WEATHER PREVAILS FOR THE REST OF
TONIGHT. EXPECTING A FEW MORE CLOUDS TONIGHT THAN LAST NIGHT...SO
HAVE MINIMUM TEMPERATURES SLIGHTLY HIGHER THAN WHAT WE SAW
TUESDAY MORNING. WINDS WILL BE SLIGHTLY HIGHER TONIGHT...RESULTING
IN WIND CHILL VALUES SIMILAR TO LAST NIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
CLOUDS INCREASE DURING THE DAY WEDNESDAY...WITH PREDOMINANTLY
OVERCAST SKIES EXPECTED FOR WEDNESDAY NIGHT. WITH A HIGH PRESSURE
CORE OVER SOUTHERN ONTARIO AND QUEBEC...THINKING WEDNESDAY WILL
REMAIN DRY.
DECENT OVERRUNNING COMBINED WITH A WEAK MID-LEVEL SHORTWAVE AND
SOME FRONTOGENESIS IN THE 925-850 MB LAYER SHOULD BE ENOUGH TO
GENERATE SOME LIGHT SNOW. ONSET TIMING COULD USE SOME
REFINEMENT...BUT CURRENTLY THINKING THE MAJORITY OF ANY SNOW
WEDNESDAY NIGHT WILL BE AFTER MIDNIGHT...AND POSSIBLY QUITE LATE
WEDNESDAY NIGHT ACROSS RI AND EASTERN MA.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
HIGHLIGHTS...
* COASTAL STORM WITH A VARIETY OF HAZARDS THURS INTO FRIDAY
* WELL BELOW AVG TEMPERATURES FOR FRI AND SAT
* ANOTHER POSSIBLE SYSTEM IMPACTING THE REGION SUN NIGHT INTO MON
CONFIDENCE LEVEL...MODERATE CONFIDENCE IN THE OVERALL TREND OF
THE FORECAST WITH A LOW CONFIDENCE IN SPECIFICS OF THE FORECAST.
HIGH CONFIDENCE IN PRECIPITATION ON THURSDAY INTO FRIDAY AS WELL
AS EXTREMELY COLD TEMPS FOR FRIDAY INTO SATURDAY. BEYOND THAT DUE
TO SIGNIFICANT MODEL DIVERGENCE...HAVE A LOW CONFIDENCE.
DETAILS...
THURSDAY INTO FRIDAY...
PIECE OF ENERGY FOR A SIGNIFICANT COASTAL SYSTEM IS STILL
OFFSHORE OF BRITISH COLUMBIA BUT WILL EVENTUALLY DIVE INTO THE
SOUTHERN PLAINS BY DAY 2. THIS ENERGY WILL DEVELOP A LOW PRESSURE
OFF THE COAST OF NC AND EVENTUALLY TRACK JUST SOUTHEAST OF THE
40N/70W BENCHMARK. ALTHOUGH NOT A TRUE BENCHMARK STORM...THIS
PROGRESSIVE SYSTEM IS STILL PACKING A LOT OF PUNCH THAT WILL
INVOLVE WIDESPREAD MINOR WITH POCKETS OF MODERATE COASTAL
FLOODING...MODERATE SNOWFALL ACCUMULATIONS...STRONG WINDS CAUSING
BLOWING AND DRIFTING SNOW AND BITTER COLD TEMPS. DETAILS BELOW.
* MODELS...MODELS ARE STARTING TO COME MORE ALIGN AMONGST ONE
ANOTHER AS BOTH DETERMINISTIC AND THEIR ENSEMBLES HAVE TRENDED
TO BE MORE PROGRESSIVE. THE CANADIAN AND UKMET STILL SEEM TO BE
OUTLIERS BEING THE FURTHEREST OUT TO SEA. THE 00Z EC HAS SPED UP
AND IS MORE PROGRESSIVE THEN ITS 12Z COUNTERPART. THE EC
ENSEMBLES ARE ALSO MORE PROGRESSIVE AND LINE UP WITH THE GEFS.
THEREFORE TRENDED THE FORECAST TOWARDS A GFS/EC/PREV FORECAST
COMPROMISE. ONE THING TO NOTE IS THAT THERE IS STILL SIGNIFICANT
SPREAD AMONGST THE INDIVIDUAL GEFS MEMBERS AS WELL AS A
SIGNIFICANT TRACK SHIFT/ERROR IS STILL POSSIBLE AS WE ARE STILL
72 HOURS OUT. SO CONTINUED WITH A BELOW CONFIDENCE FORECAST.
* TEMPS...NO ISSUES WITH P-TYPE AS THERMAL PROFILES WILL ALL BE
BELOW 0C. SURFACE TEMPERATURES WILL BE BELOW AVERAGE AT THE ONSET
OF THIS SYSTEM BUT WILL QUICKLY PLUMMET INTO THE SINGLE DIGITS ONCE
WHEN THE WINDS SWITCH TO A NORTHERLY DIRECTION. THIS WILL ALLOW
FOR A MORE POWDERY SNOW. THE EXPECTED GUSTY WINDS COMBINED WITH
THE VERY COLD TEMPERATURES...WIND CHILL ADV MAY BE NEEDED FOR
CENTRAL AND WESTERN MA AS WIND CHILL VALUES DROP BELOW -15F.
* SNOW...HIGH CONFIDENCE THAT P-TYPE WILL BE ALL SNOW THANKS TO
THE REINFORCING ARCTIC AIR MOVING INTO SOUTHERN NEW ENGLAND
DURING THE EVENT. FOR EXAMPLE...925MB TEMPS RANGE BETWEEN -18C
TO -6C ACROSS THE AREA FROM THURSDAY INTO FRIDAY. SOUNDING AND
MODELS SHOW DEEP SATURATION THROUGHOUT THE SNOW GROWTH REGION SO
HAVE LITTLE DOUBT THAT MOISTURE WILL BE AN ISSUE. TRENDED QPF AS
A COMBO OF THE GFS/EC AS IT IS IN GOOD JUNCTION WITH ITS
ENSEMBLES. OVERALL APPEARS THAT AT LEAST 0.5 INCHES OF QPF WILL
FALL THROUGHOUT THE EVENT WITH HIGHER AMOUNTS LIKELY NEAR THE
EAST COASTLINE. FINALLY WITH PERSISTENT NORTHEAST WIND...THERE
IS A POSSIBILITY OF OCEAN EFFECT SNOW SHOWERS. LOOKING AT ALL OF
THESE FACTORS...THERE IS INCREASING CONFIDENCE THAT AT LEAST 6
INCHES OF SNOW WILL OCCUR WITH POSSIBLE HIGHER AMOUNTS CLOSER TO
THE EAST AND SE COASTLINES. THE REGION OF HIGHEST UNCERTAINTY IS
ACROSS S NH AND NW MA WHERE A SHIFT IN THE TRACK COULD REDUCE
THEIR AMOUNTS. AS MENTIONED BEFORE THERE IS STILL A LOT OF
UNCERTAINTY AND THESE AMOUNTS AND PROJECTIONS COULD SHIFT A FEW
MORE TIMES.
* WIND...SIGNIFICANT PRESSURE GRADIENT WITH THIS SYSTEM AS IT MOVES
SOUTH AND EAST OF THE BENCHMARK. THIS WILL CREATE VERY GUSTY WINDS
ACROSS THE AREA. 925 MB WIND SPEEDS SHOW A JET BETWEEN 40-55 KTS
LATE THURSDAY INTO FRIDAY MORNING OVER THE SOUTHERN COASTAL PLAIN
INCLUDING RI COAST...THE CAPE AND THE ISLANDS. THIS MAY ALLOW FOR
SURFACE WINDS TO SUSTAIN AROUND 20 TO 30MPH ACROSS THE MENTIONED
REGION WITH GUSTS BETWEEN 35 TO 45MPH. WITH THESE KIND OF
GUSTS...EXPECT SIGNIFICANT BLOWING AND DRIFTING SNOW...REDUCING
VSBYS. AGAIN THE MAIN REGION OF CONCERN FOR THE STRONG WIND GUSTS
IS ACROSS THE SE COASTAL PLAIN INCLUDING THE RI COAST...CAPE AND
THE ISLANDS.
* COASTAL FLOODING...SEE DISCUSSION BELOW.
FRIDAY NIGHT INTO SUNDAY...STORM SYSTEM WILL EJECT INTO THE GULF
OF MAINE BY FRIDAY NIGHT ALLOWING FOR HIGH PRESSURE TO BUILD IN
ACROSS THE REGION. THIS ARCTIC HIGH PRESSURE WILL ALLOW FOR
SIGNIFICANT RADIATIONAL COOLING ON FRIDAY NIGHT. TEMPS WILL BE
WELL BELOW AVERAGE WITH SURFACE TEMPERATURES AT LEAST 2 TO 3
STANDARD DEVIATIONS AWAY. TEMPS WILL DROP BELOW ZERO INCLUDING THE
METRO REGIONS. WARM SPOTS WILL BE THE CAPE AND THE ISLANDS THANKS
TO THE WARMER OCEAN WATERS. THESE BITTER COLD TEMPS MAY WARRANT A
WIND CHILL ADVISORY FRIDAY NIGHT AS WIND CHILLS DROP TO BELOW -20F
NORTH OF THE MASS PIKE...WITH -15F NORTH OF I-95...INCLUDING THE
CITY OF BOSTON.
SLIGHT RIDGING ALOFT WILL ALLOW FOR A WARMUP ON SATURDAY AND INTO
SUNDAY. SAT HIGHS WILL ONLY REACH THE MID TEENS TO LOW 20S WHILE
HIGHS SUNDAY WILL BE ABOVE FREEZING THANKS TO SIGNIFICANT WAA AT
850MB.
SUNDAY NIGHT INTO MONDAY...
MODELS GREATLY DIVERGE FOR THIS TIMEFRAME. APPEARS ANOTHER SYSTEM
WILL APPROACH THE REGION DURING THE SUNDAY NIGHT INTO MONDAY
TIMEFRAME. STILL A LOT OF UNCERTAINTY AS THE GFS BRINGS A COLD
FRONT ACROSS THE REGION WHILE THE LATEST EC TRIES TO DEVELOP AN
INLAND RUNNER. FOR NOW FOLLOWED WPC AND KEPT CHANCE POPS IN FOR
THIS TIME FAME AND WILL HASH OUT THE DETAILS LATER THIS WEEK.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /TODAY THROUGH WEDNESDAY AFTERNOON/...
THROUGH TONIGHT...HIGH CONFIDENCE VFR CONDITIONS MOST LOCATIONS.
THE EXCEPTION WILL BE BRIEFLY SCATTERED MVFR CIGS/VSBYS LATE THIS
AFTERNOON AND EARLY EVENING ACROSS THE WESTERN HALF OF SOUTHERN
NEW ENGLAND IN SNOW SHOWERS.
WEDNESDAY...HIGH CONFIDENCE VFR.
WEDNESDAY NIGHT...HIGH CONFIDENCE IN TRENDS...MODERATE CONFIDENCE
IN TIMING. CONDITIONS LOWERING TO MVFR IN SNOW...MAINLY AFTER
MIDNIGHT.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF. LOW PROBABILITY OF BRIEF MVFR
CONDITIONS LATE THIS AFTERNOON/EARLY EVENING.
OUTLOOK...THURSDAY THROUGH SUNDAY...MODERATE CONFIDENCE.
THURSDAY...IFR CIGS/VSBYS IN SNOW. THIS MAY LEAD TO SIGNIFICANT
ACCUMULATIONS...ESPECIALLY IN THE LATE AFTERNOON AND AT NIGHT.
EAST TO NORTHEAST WINDS WITH GUSTS 30 TO 45 KT ALONG THE COAST.
FRIDAY...IFR CONDITIONS IN SNOW TO START THE DAY. CONDITIONS
IMPROVING TO VFR FRIDAY AFTERNOON ACROSS WESTERN NEW ENGLAND. BRIEF
WIND GUSTS UP TO 40 KT POSSIBLE WITH THE INITIAL SURGE OF ARCTIC AIR
BEHIND DEPARTING LOW PRESSURE.
SATURDAY...VFR WITH SOME GUSTY WINDS NEAR THE COAST.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /TODAY THROUGH WEDNESDAY NIGHT/...HIGH CONFIDENCE.
TONIGHT...A COLD FRONT CROSSES THE WATERS WITH A ROUND OF STRONG
WESTERLY WIND GUSTS UP TO 30 KT. SMALL CRAFT ADVISORIES POSTED
FOR MOST WATERS ALONG WITH POTENTIAL FOR LIGHT FREEZING SPRAY.
THERE COULD BE A BRIEF PERIOD OF GALE FORCE GUSTS BETWEEN 4 PM AND
9 PM. DECIDED TO NOT ISSUE A GALE WARNING AS GUSTS ARE MARGINAL
AND IT IS FOR A RELATIVELY SHORT PERIOD OF TIME.
WEDNESDAY...SMALL CRAFT ADVISORY WINDS/SEAS EARLY SHOULD
TEMPORARILY DIMINISH BELOW CRITERIA ACROSS ALL WATERS BY MID
AFTERNOON AS HIGH PRESSURE MOVES ACROSS THE WATERS.
WEDNESDAY NIGHT...RELATIVELY LIGHT WINDS AND SEAS EXPECTED. WINDS
TURN EAST AHEAD OF A NOREASTER MOVING SOUTH OF THE WATERS. SEAS
BEGIN TO REBUILD LATE WEDNESDAY NIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...MODERATE CONFIDENCE.
THURSDAY...WINDS INCREASE OUT OF THE EAST IN THE MORNING WITH
EAST TO NORTHEAST GUSTS TO 40 KNOTS DEVELOPING IN THE EVENING.
SEAS BUILD ABOVE 5 FEET BY AFTERNOON. THE EASTERN MASSACHUSETTS
WATERS MAY HAVE SEAS BUILD TO 15 FEET OVERNIGHT. GALE WARNINGS
WILL BE NEEDED.
FRIDAY...NORTH WINDS WITH GUSTS OF 30-45 KNOTS. EASTERN SEA
HEIGHTS WILL BE 10 TO 20 FEET...SOUTHERN OCEAN WATERS WILL BE 10
TO 15 FEET. GALE WARNINGS WILL WILL BE NEEDED.
SATURDAY...WINDS AND SEAS DIMINISH AS A HIGH PRESSURE BUILDS OVER
THE WATERS. SMALL CRAFT ADVISORIES LIKELY TO CONTINUE...AT LEAST
ACROSS THE OUTER COASTAL WATERS.
&&
.TIDES/COASTAL FLOODING...
LATEST ECMWF MODEL AND ITS ENSEMBLES HAS TRENDED MORE TOWARDS OTHER
GUIDANCE IN SHOWING A MORE PROGRESSIVE/FURTHER SOUTHEAST TRACK WITH
COASTAL STORM THU-FRI.
NONETHELESS...ASTRONOMICAL HIGH TIDES ARE VERY HIGH WITH 12.2 FEET
AT BOSTON THU AND FRI...AT 11:22 AM AND 12:15 PM RESPECTFULLY.
THERE ALSO IS A 10.9 FOOT HIGH TIDE THU NIGHT AROUND MIDNIGHT.
THEREFORE...EXPECT WIDESPREAD MINOR WITH THE POTENTIAL FOR POCKETS
OF MODERATE COASTAL FLOODING DURING THESE 3 HIGH TIDE CYCLES ALONG
THE EASTERN MA COAST. ANOTHER CONCERN WILL BE FOR BEACH EROSION IN
THIS REGION.
NOT EXPECTING ANY COASTAL FLOODING PROBLEMS ALONG THE SOUTH COAST
GIVEN WIND DIRECTION AND EXPECTED TRACK OF THE STORM.
&&
.CLIMATE...
RECORD MINIMUM HIGH TEMPERATURES FOR JANUARY 3RD...
BOSTON 7 /1904/
HARTFORD 7 /1981/
PROVIDENCE 10 /1918/
WORCESTER 4 /1904/
RECORD LOW TEMPERATURES FOR JANUARY 4TH...
BOSTON -4 /1981/
HARTFORD -7 /1981/
PROVIDENCE -9 /1981/
WORCESTER -8 /1981/
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
WEDNESDAY FOR ANZ231>235-237-250-251.
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 4 AM EST
WEDNESDAY FOR ANZ230.
SMALL CRAFT ADVISORY UNTIL 4 PM EST WEDNESDAY FOR ANZ254>256.
&&
$$
SYNOPSIS...BELK/DUNTEN
NEAR TERM...BELK
SHORT TERM...BELK
LONG TERM...DUNTEN
AVIATION...BELK/DUNTEN
MARINE...BELK/DUNTEN
TIDES/COASTAL FLOODING...STAFF
CLIMATE...STAFF
AREA FORECAST DISCUSSION
NWS NEW YORK NY
100 PM EST TUE DEC 31 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION LATE TODAY. ARCTIC HIGH
PRESSURE BUILDS TO THE NORTH OF THE REGION THROUGH MIDWEEK. A
STALLED FRONTAL BOUNDARY DEVELOPS NEAR THE AREA WED NIGHT WITH
WEAK LOW PRESSURE APPROACHING FROM THE OHIO VALLEY. A STRONGER LOW
PRESSURE SYSTEM WILL DEVELOP OFF THE CAROLINA COAST ON THURSDAY
AND TRACK NORTHEAST PASSING SOUTHEAST OF LONG ISLAND THURSDAY
NIGHT INTO FRIDAY. HIGH PRESSURE RETURNS FOR THE WEEKEND WITH A
FRONTAL SYSTEM MOVING THROUGH SUN NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MAX TEMPS WERE LOWERED SLIGHTLY BY A FEW DEGREES TO MATCH OBSERVED
TRENDS WITH TEMPERATURES. LOOKING AT PARAMETERS OF
FRONTOGENESIS...SURFACE BASED CAPE...POTENTIAL INSTABILITY...THE
INCREASE IN FRONTOGENESIS COMBINED WITH LESS THAN 50 J/KG OF CAPE
AS WELL AS A LITTLE POTENTIAL INSTABILITY FROM NEGATIVE TREND OF
THETA-E WITH HEIGHT...POTENTIAL IS THERE FOR SNOW SHOWERS AND SNOW
SQUALLS AS WELL. HRRR AND HIRES NMM BOTH SHOW DISCRETE CELLS OF
20-30 DBZ MOVING ACROSS IN THE 21Z-00Z TIMEFRAME. THEREFORE THAT
PORTION OF THE FORECAST REMAINS NEARLY THE SAME AS BEFORE. A
SLIGHT ADJUSTMENT UP WAS MADE WITH SNOW ACROSS INTERIOR SECTIONS
WHERE HIGHER OMEGA WAS SEEN WITHIN THE DENDRITIC SNOW GROWTH ZONE
COMPARED TO FARTHER SOUTH WHERE LESS OMEGA WAS SEEN IN THIS ZONE.
THIS ANALYSIS WAS DONE LOOKING AT BUFKIT SOUNDINGS.
POTENTIAL FOR LOCALIZED SNOW SQUALLS WITH FLASH FREEZE CONDITIONS
DURING EVENING COMMUTE...
MODELS IN GOOD AGREEMENT WITH NORTHERN STREAM SHORTWAVE AND
ACCOMPANYING CLIPPER OVER THE GREAT LAKES EARLY THIS
MORNING...SWINGING INTO THE NORTHEAST THIS AFTERNOON. MODELS
CONTINUE TO SHOW SOUTHERN STREAM ENERGY STAYING UNPHASED...WITH
ANY COASTAL DEVELOPMENT STAYING WELL SOUTH OF THE REGION.
SHORTWAVE APPROACHES THIS MORNING WITH INCREASING CLOUD COVER
ACROSS THE AREA...AND PIVOTS THROUGH THIS AFTERNOON. CLIPPER LOW
STAYS WELL TO THE NORTH BUT TRAILING COLD FRONT PUSHES THROUGH
LATE TODAY/THIS EVENING.
COMBINATION OF MODEST SHORTWAVE LIFT AND MOISTURE CONVERGENCE
AHEAD OF COLD FRONT...WITH A BIT OF LOW-LEVEL INSTABILITY...POINTS
TOWARDS SCATTERED SNOW SHOWER ACTIVITY WORKING INTO WESTERN
PORTIONS OF THE REGION LATE THIS AFTERNOON AHEAD OF THE COLD
FRONT...AND THEN TRAVERSING EAST THROUGH EARLY EVENING. COVERAGE
LIKELY IN THE 25 TO 35 PERCENT RANGE. BASED ON ABOVE AND HIGH RES
MODEL OUTPUT...ISOLATED SNOW SQUALLS (15-20 PERCENT PROBABILITY) WITH
BRIEF WHITE OUT CONDITIONS AND A QUICK COATING OF SNOW ARE
POSSIBLE. ANY AREA EXPERIENCING A SNOW SQUALL WILL HAVE POTENTIAL
FOR FLASH FREEZE CONDITIONS AS TEMPS START OUT AROUND OR JUST
ABOVE FREEZING AND THEN DROP INTO THE 20S IN THE WAKE OF COLD
PASSAGE.
ANY SNOW SHOWER/SNOW SQUALL ACTIVITY WILL QUICKLY COME TO AN END
BEHIND FRONTAL PASSAGE...WITH A BRIEF PERIOD OF STRONG WINDS GUSTS
LIKELY IMMEDIATELY BEHIND COLD FRONTAL PASSAGE LATE THIS
AFTERNOON/EARLY EVENING. GUSTS TO 35 MPH LIKELY AND TO 40 MPH
POSSIBLE DURING THE LATE AFTERNOON/EARLY EVENING WITH DEEP MIXING
AND WIND PROFILE SUPPORTING GOOD MOMENTUM TRANSFER.
TEMPS LIKELY A COUPLE OF DEGREES BELOW SEASONABLE TODAY
PARTICULARLY ACROSS INTERIOR WITH INCREASING CLOUD COVER AND
ARCTIC AIRMASS IN PLACE. WILL LEAN TOWARDS COLDER MET GUIDANCE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
SHORTWAVE ENERGY PIVOTS WELL NORTH OF THE REGION THIS EVENING...WITH
COLD FRONT PASSING TO THE EAST.
MODERATELY STRONG WINDS AND GUSTS SHOULD GRADUALLY WEAKEN THROUGH
THE OVERNIGHT AS HIGH PRESSURE BUILDS IN.
BAND OF STRATO-CU AND A FEW FLURRIES MAY LINGER ACROSS FAR NW ZONES
IN THE EVENING AT TAIL END OF LAKE STREAMERS...OTHERWISE
SKIES CLEAR IN WAKE OF THE FRONT THIS EVENING.
ZONAL UPPER FLOW ON WEDNESDAY AROUND POLAR VORTEX DRIFTING EAST
THROUGH CENTRAL QUEBEC...WITH ARCTIC HIGH PRESSURE BUILDS INTO
NORTHERN NEW ENGLAND. MOISTURE WILL LIKELY BE STREAMING EASTWARD ON
WEDNESDAY AS AN OVERRUNNING PATTERN DEVELOPS OVER THE ARCTIC
AIRMASS...BUT SOME UNCERTAINTY EXITS ON WHERE MAIN AXIS OF MOISTURE
WILL LIE. BUT OVERALL PATTERN SUGGEST INCREASING CLOUD COVER AND
POTENTIAL FOR LIGHT SNOW DEVELOPMENT ACROSS FAR NW ZONES TOWARDS
EVENING.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
POTENTIAL FOR A SIGNIFICANT COASTAL STORM LATE THIS
WEEK...FOLLOWED BY BITTERLY COLD TEMPERATURES...
00Z DETERMINISTIC MODELS HAVE COME INTO BETTER ALIGNMENT YIELDING
HIGHER CONFIDENCE FOR A SIGNIFICANT COASTAL STORM TO IMPACT THE AREA
LATE THIS WEEK. HOWEVER...WOULD LIKE TO SEE ANOTHER CONSISTENT SET
OF DATA BEFORE ISSUING ANY WATCHES.
H5 FLOW ACROSS THE CONUS BEGINS WITH RIDGING IN THE WEST...A DIGGING
TROUGH IN THE PLAINS AND ZONAL FLOW IN THE EAST. THE TROUGH WILL
AMPLIFY AS IT CONTINUES TO DEEPEN THU AND FRI AND MOVES TOWARDS THE
EASTERN SEABOARD.
AT THE SFC...A STALLED FRONTAL BOUNDARY WILL STRETCH FROM THE UPPER
MID WEST TO SOUTHERN NEW ENGLAND ON THU WITH A WEAK AREA OF LOW PRES
DEVELOPING ALONG IT. THE COMBINATION OF A 130 KT RRQ UPPER JET AND
INCREASING ISENTROPIC LIFT BETWEEN THE 275K TO 290K PLANES WILL
RESULT IN LIGHT PRECIPITATION TO DEVELOP ACROSS INTERIOR PORTIONS OF
THE LOWER HUDSON VALLEY AND SW CT WED EVE WITH CHANCES INCREASING
ACROSS THE ENTIRE AREA OVERNIGHT. TEMPS WILL BE COLD ENOUGH FOR SNOW
ALTHOUGH IT WILL BE LIGHT.
ATTENTION THEN TURNS TO CYCLOGENESIS OCCURRING OFF THE CAROLINA COAST
AS SHORTWAVE ENERGY WITHIN THE DIGGING UPPER TROUGH CONSOLIDATES
WITH SOUTHERN STREAM ENERGY OVER THE GULF OF MEXICO AND SOUTHEAST
STATES ON THU. THE LOW WILL DEEPEN AS IT TRACK NE THU NIGHT AND ALL
MODELS ARE INDICATING IT PASSES WELL OUTSIDE OF THE 40N 70W
BENCHMARK. HOWEVER...CONFIDENCE IS INCREASING FOR A SIGNIFICANT
SNOWFALL EVENT ACROSS THE ENTIRE AREA. THERE IS THE POTENTIAL THAT
SOUTHERN LONG ISLAND/NYC COULD SEE A MIX OR CHANGEOVER...BUT CURRENT
THINKING IS THAT IT REMAINS COLD ENOUGH FOR SNOW. HEAVIEST SNOWFALL
WILL BE THU NIGHT INTO FRI MORNING WHERE 4-6 INCHES COULD FALL. OF
COURSE AMOUNTS WILL BE HIGHER WHERE ANY MESOSCALE BANDS OCCUR...SO
CURRENT THINKING IS 5 TO 9 INCHES ACROSS THE ENTIRE CWA...HIGHEST
AMOUNTS ACROSS INTERIOR LOCATIONS.
IN ADDITION TO THE SNOW WILL BE STRONG NLY WINDS. AS THE STORM
DEEPENS THE GRADIENT WILL TIGHTEN WITH WINDS RANGING FROM 20 TO 30
MPH AND GUSTS BETWEEN 30 AND 45 MPH. THE STRONGEST WINDS WILL BE
ACROSS THE TWIN FORKS OF LONG ISLAND.
THE UPPER TROUGH AXIS PUSHES E OF THE AREA ON FRI WITH A DEEP NW
FLOW FLATTENING AND A RIDGE OF HIGH PRES MOVING ACROSS ON SAT. A
BITTERLY COLD AIRMASS...THE COLDEST OF THE SEASON...WILL THEN BE
UPON US FRI/FRI NIGHT. HIGHS WILL STRUGGLE TO GET OUT OF THE TEENS
EXCEPT PERHAPS IN NYC AND ON LONG ISLAND WHERE THEY WILL TOP OUT IN
THE LOWER 20S. FRI NIGHT WILL DROP INTO THE SINGLE DIGITS AT THE
COAST AND FALL BELOW ZERO INLAND. WIND CHILLS WILL BE IN THE SINGLE
DIGITS AT THE COAST TO A FEW DEGREES BELOW ZERO INLAND DURING THE
DAY AND GENERALLY FROM AROUND -2F TO -10F RESPECTIVELY FRI NIGHT.
FOCUS HAS BEEN ON THE UPCOMING STORM AND THEREFORE HAVE NOT MADE
MANY CHANGES TO THE REMAINDER OF THE FORECAST BEYOND FRI. THERE ARE
SIGNIFICANT DIFFERENCES IN THE GUIDANCE FOR EARLY NEXT WEEK AND FELT
IT WAS PRUDENT TO CONTINUE WITH PERSISTENCE ATTM. OVERALL...A
NORTHERN CANADIAN VORTEX WILL DROP INTO CENTRAL CANADA THIS WEEKEND
WITH A BROAD LONGWAVE TROUGH ENCOMPASSING THE LOWER 48 INTO EARLY
NEXT WEEK. THE EC BRINGS THIS VORTEX INTO THE GREAT LAKES REGION
BEFORE LIFTING IT BACK N WHILE THE GFS KEEPS IT NEAR HUDSON BAY.
THIS DIFFERENCES LEAD TO LARGE VARIATIONS IN OUR LOCAL WEATHER.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
LOW PRESSURE OVER THE EASTERN GREAT LAKES WILL MOVE EAST ACROSS
NORTHERN NEW ENGLAND AS ITS TRAILING FRONT MOVES EAST ACROSS THE
REGION THIS AFTERNOON. HIGH PRESSURE WILL FOLLOW THROUGH WEDNESDAY.
VFR WEATHER WILL PREVAIL OUTSIDE OF SNOW SHOWERS. THERE IS A CHC OF
MVFR CIGS AND VSBYS IN HEAVIER SNOW SHOWERS UNTIL 22Z. ALL UPDATED
TAFS INCLUDE SNOW SHOWERS IN VCNTY.
WINDS TODAY...SW 230-250 DEGS WILL INCREASE TO 15-20 KT AHEAD OF
APPROACHING FRONT THEN SHIFT FROM THE W 270-290 DEGS NEAR 20 KT WITH
GUSTS TO 30 KT MAINLY 21Z - 02Z.
WINDS TONIGHT...GUSTS WILL DISSIPATE BY MIDNIGHT...05Z AND
SUSTAINED W WINDS WILL DECREASE TO 10 KT OR LESS.
WINDS NEW YEARS DAY...W ARND 10 KT BECOMING SW DURING THE AFTN.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: CHC TEMPO CIGS 2000-3000FT AND REDUCED VSBYS
IN -SHSN FROM 18-22Z.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: CHC TEMPO CIGS 2000-3000FT AND REDUCED VSBYS
IN -SHSN FROM 18-22Z.
KLGA FCSTER COMMENTS: CHC TEMPO CIGS 2000-3000FT AND REDUCED VSBYS
IN -SHSN FROM 18-22Z.
KTEB FCSTER COMMENTS: CHC TEMPO CIGS 2000-3000FT AND REDUCED VSBYS
IN -SHSN FROM 18-22Z.
KHPN FCSTER COMMENTS: CHC TEMPO OR PREVAILING CIGS 2000-3000FT AND
REDUCED VSBYS IN -SHSN FROM 18-22Z.
KISP FCSTER COMMENTS: CHC TEMPO OR PREVAILING CIGS 2000-3000FT AND
REDUCED VSBYS IN -SHSN FROM 20-23Z.
.OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
.WEDNESDAY...VFR.
.WEDNESDAY NIGHT...MVFR OR LOWER POSSIBLE LATE IF SNOW DEVELOPS. E
GUSTS AROUND 20 KT POSSIBLE LATE AS WELL.
.THURSDAY-FRIDAY...SNOW LIKELY WITH IFR AND LOWER CONDITIONS.
SIGNIFICANT ACCUMULATION POSSIBLE. GUSTS 30-40 KT POSSIBLE. WINDS
BACK FROM E-NE THURSDAY TO NW FRIDAY. SNOW ENDS FRIDAY MORNING. BCMG
VFR BY DAY`S END.
.FRIDAY NIGHT...VFR. NW GUSTS 20-30 KT DURING THE EVENING.
.SATURDAY AND EARLY SUNDAY...VFR. MVFR CIGS POSSIBLY DEVELOPING
SUNDAY AFTN AND EVENING.
&&
.MARINE...
FORECAST ON TRACK SEEING SOME INCREASE IN WINDS ACROSS THE WATERS
FOR EARLY THIS AFTERNOON.
WINDS THEN PICK UP TO SCA LEVELS LATE THIS AFTERNOON AND CONTINUE
THROUGH TONIGHT IN THE WAKE OF A COLD FRONTAL PASSAGE. A BRIEF
PERIOD OF GALE FORCE ARE POSSIBLE MAINLY BETWEEN 21Z-
03Z...PARTICULARLY ON THE OCEAN WATERS WITH AGREEMENT IN THE NAM
AND GFS BUFKIT PROFILES. SEAS LIKELY BUILD TO 6 TO 8 FT ON
EASTERN OCEAN IN RESPONSE TO STRONG WNW FLOW...WITH 5 FT SEAS ON
CENTRAL AND EASTERN SOUND.
SUB SCA WINDS LIKELY RETURN BY WED MORNING AS HIGH PRESSURE
BRIEFLY BUILDS OVER THE WATERS.
SUB-ADVSY CONDS WILL CONTINUE THROUGH WED NIGHT...BUT SCA CONDS WILL
RETURN ON THU ON ALL WATERS...WITH GALES BECOMING MORE LIKELY ON
MOST OF THE WATERS THU NIGHT AND FRI AS A COASTAL STORM PASSES TO
THE S AND E. CONDS IMPROVE FRI NIGHT...ALTHOUGH SCA CONDS WILL
LIKELY BE NEEDED WITH ADVSY LEVEL SEAS LINGERING ON THE OCEAN WATERS
INTO SAT MORNING. SUB-ADVSY CONDS ARE THEN EXPECTED THROUGH THE
REMAINDER OF THE FORECAST PERIOD WITH HIGH PRES BUILDING TOWARDS THE
AREA.
&&
.HYDROLOGY...
A COASTAL STORM IMPACTING THE AREA FROM WED NIGHT INTO FRI HAS THE
POTENTIAL TO PRODUCE BETWEEN 1/2 AND 1 INCH OF LIQUID EQUIVALENT
PRECIPITATION AMOUNT. CURRENTLY...IT APPEARS THAT ALL AREAS WILL
RECEIVE THIS IN SOLID FORM...THEREFORE NO HYDROLOGIC IMPACTS ARE
EXPECTED.
&&
.TIDES/COASTAL FLOODING...
INCREASING LIKELIHOOD FOR MINOR COASTAL FLOODING DURING THE THURSDAY
MORNING HIGH TIDE CYCLE WITH STRENGTHENING E/NE WINDS AND
ASTRONOMICALLY HIGH TIDES. POTENTIAL EXITS FOR LOW END MODERATE
COASTAL FLOODING ALONG WESTERN LONG ISLAND SOUND AND EASTERN
BAYS...AND POSSIBLY WESTERN GREAT SOUTH BAY. THE MODERATE COASTAL
FLOOD THREAT SHOULD BECOME CLEARER OVER THE NEXT 24 HOURS.
THU NIGHT HIGH TIDAL CYCLES IS LOWER OF THE TWO AND LATEST THINKING
IS THAT SOLID GALES WILL BE TURNING NORTH DURING THIS TIDAL
CYCLE...WHICH SHOULD LIMIT COASTAL FLOODING IMPACTS MAINLY TO MINOR.
NORTH FACING SHORELINES WOULD BE MOST VULNERABLE...AND IT SHOULD BE
NOTED THAT THESE NORTHERLY GALE EVENTS ARE KNOWN TO CAUSE MORE
SERIOUS COASTAL IMPACTS ALONG THE NORTH FACING PORTIONS OF THE TWIN
FORKS OF LONG ISLAND DUE TO COMBINED STORM TIDE AND WAVE ACTION.
WITH OFFSHORE GALES DEVELOPING FOR FRI MORNING HIGH TIDE
CYCLE...MINOR COASTAL FLOODING SHOULD BECOME MORE LOCALIZED...MAINLY
IN BACK BAY AREAS DUE TO LIMITED TIDAL DRAINAGE.
IN ADDITION...HIGH SURF OF 7 TO 10 FT WITH ENE TO WSW SWEEP LATE
THURSDAY INTO FRIDAY WILL LIKELY RESULT IN MINOR BEACH EROSION
ISSUES ALONG ATLANTIC OCEAN FACING BEACHES OF LONG ISLAND AND
PARTICULARLY THE SOUTH FORK OF LI.
SOME UNCERTAINTY STILL EXISTS IN THE TRACK AND TIMING OF THIS
COASTAL STORM WHICH WOULD CAUSE SOME MODIFICATION TO ABOVE
FORECAST...SO MONITOR SUBSEQUENT FORECAST FOR THE LATEST.
&&
.EQUIPMENT...
THE NEW YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 IS
OUT OF SERVICE.
DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY
BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER
RADIO STATION KWO35 IS OUT OF SERVICE.
DURING THE TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE
INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO
DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE
WEEKLY TEST OF THE WARNING SYSTEM...AND TO DETERMINE IF THE
INTERFERENCE ISSUE HAS BEEN RESOLVED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST WEDNESDAY FOR ANZ330-335-
338-340-345-350-353-355.
&&
$$
SYNOPSIS...24/NV
NEAR TERM...JM/NV
SHORT TERM...NV
LONG TERM...24
AVIATION...GC
MARINE...24/JM/NV
HYDROLOGY...24/NV
TIDES/COASTAL FLOODING...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
306 PM CST TUE DEC 31 2013
.SYNOPSIS...
ISSUED AT 304 PM CST TUE DEC 31 2013
THE NARROW AXIS OF MODERATE SNOW IS POSITIONED IN THE NORTHERN 1/4
OF THE CWA BY MID AFTERNOON. BY OBSERVATIONS...WEBCAMS AND
CALLS...THERE HAS BEEN ROUGHLY 1 INCH PER HOUR FALLING IN THIS AREA
SINCE AROUND NOON. FARTHER SOUTH...A STRONG STATIONARY FRONT IS
LOCATED NEAR THE IOWA/MISSOURI BORDER...EASILY SEEN IN OBS THAT
RANGE FROM THE MID 30S TO THE MID TEENS IN A FEW TENS OF MILES IN
OUR SOUTH. STRONG FRONTOGENESIS IS CAUSING THE SNOW TO THE NORTH OF
THE FRONT...AND THIS TYPE OF FORCING WILL ALSO DOMINATE TOMORROW.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 304 PM CST TUE DEC 31 2013
FRONTOGENESIS WILL CONTINUE THROUGH AROUND 9 PM IN THE NORTH...THEN
WILL SLOWLY SETTLE SOUTH IN A WEAKENING FASHION. THIS SHOULD LEAD TO
LIGHTER SNOWS AFTER MID EVENING...BUT WITH 3 TO 5 ALREADY ON THE
GROUND IN THE NORTH...WILL CONTINUE THE ADVISORY THROUGH 12Z.
FARTHER SOUTH ALONG THE HIGHWAY 30 TO INTERSTATE 80 CORRIDORS...THE
BEST CHANCE FOR MEASUREABLE SNOW WILL HOLD OFF UNTIL THIS FORCING
ARRIVES FROM THE NORTH MID EVENING. OVERNIGHT SNOW TOTALS SHOULD BE
1 TO 2 INCHES NORTHEAST TO AN INCH OR INTO THE CENTRAL CWA.
ANOTHER...ARGUABLY STRONGER ROUND OF FRONTOGENESIS ARRIVES EARLY
WEDNESDAY MORNING...LIKELY CONTINUING ALL DAY AS IS GRADUALLY
SETTLES SOUTH. THIS TOO SHOULD HAVE SNOW RATIOS OF 15 TO 20:1...AND
AMOUNTS OF SNOW WILL BE RATHER FLUFFY. THE NAM AND GEM BOTH CARRIED
THIS IDEA IN PAST RUNS AND CURRENT...BUT IS NOW SUPPORTED BY THE 12Z
GFS...12Z ECMWF...12Z UKMET...NMM EAST...SPC WRF AND LAST HOURS OF
THE RAP RUNS. THUS...WE HAVE HIGH ENOUGH CONFIDENCE ISSUE A WINTER
WEATHER ADVISORY SNOW OVER CENTRAL CWA FROM 6 AM WEDNESDAY TO 6 PM
WEDNESDAY. WE ARE GENERALLY LOOKING FOR 3 TO 4 INCHES OF SNOW IN A 6
HOUR WINDOW OF TIME. THIS SUPPORTS ADVISORY ISSUANCE. SHOULD THE
MESOCALE MODELS BE CORRECT ON THE STRENGTH OF FORCING...WE COULD BE
LOOKING AT AMOUNTS WITHIN THE BAND FROM OTTUMWA TO THE QUAD CITIES
IN THE 4 TO 7 INCH RANGE. HOWEVER...CONFIDENCE IS HIGHER FOR TOTALS
IN THE 3 TO 4 INCH RANGE. TEMPERATURES WILL BE VERY COLD AGAIN
TONIGHT AND WEDNESDAY...AS WINDS FROM THE NORTHEAST DRAW IN THE SAME
AIRMASS WE HAD YESTERDAY. THE WARMTH IN THE FAR SOUTH JUST IS NOT
COMING OUR WAY IN THIS FORECAST.
ERVIN
.LONG TERM...(WEDNESDAY NIGHT THROUGH NEXT TUESDAY)
ISSUED AT 304 PM CST TUE DEC 31 2013
WEDNESDAY NIGHT AND THURSDAY...LATEST 12Z RUN MODELS HAVE COME
AROUND WITH RESPECT TO EXTENT OF FORCING ACRS AND SOUTH OF THE CWA
WED EVENING AS UPPER VORT PIVOTS IN TROF BASE ACRS SOUTHEAST IA.
DECENT ELEVATED FRONTOGENESIS RIBBON ALONG AND NORTH OF CENTRAL IL
INTO SOUTHEASTERN PLAINS SFC FRONT...ALONG WITH ISENTROPIC LIFT
ANALYSIS ON 285K SFC SHOULD LAY DOWN AN ADDITIONAL 0.5 UP TO OVER AN
INCH IN THE SOUTHEASTERN QUARTER OF THE DVN CWA FROM 00Z-03Z OR SO
AND WORRIED IT MAY BE MORE TAKING INTO ACCOUNT USED 17:1 OR
HIGHER LSR/S. BUT FOR NOW WILL ALLOW THE ADVISORY END AT 00Z
COORDINATING WITH THE ABOVE SHORT TERM DISCUSSION. THUS EVEN THE
HWY 34 CORRIDOR AND AREAS TO THE SOUTH MAY END UP WITH 1-3 INCHES BY
MIDNIGHT THU NIGHT TAKING INTO ACCOUNT SNOWFALL LATE WED AFTERNOON
AND INTO THE EVENING. THEN AS L/W PHASING PROCESS SHIFTS OFF TO THE
EAST/SOUTHEAST OF THE REGION...ANOTHER BOUT OR INCOMING ARCTIC
HIGH PRESSURE TO DEAL WITH...WITH THE PRESSURE GRADIENT INDUCING OR
MAINTAINING 7-11KT WINDS INTO THU MORNING. SIDING WITH THE COOLER
MAV BUT GOING ABOVE IT TAKING INTO ACCOUNT MIXING WINDS AND
LINGERING CLOUD COVER...STILL MANY SUBZERO READINGS WILL OCCUR OVER
THE NORTHWESTERN THIRD OF THE CWA IN DEEPER SNOWPACK...MAY NOT BE
GOING COLD ENOUGH ALONG THE I80 CORRIDOR. THESE COLD AMBIENT TEMPS
WHEN COMBINED WITH THE WINDS WILL PROBABLY MAKE FOR WIND CHILL
ADVISORY CRITERIA EARLY THU MORNING. BOTH THE 12Z GFS AND ECMWF
SLIDE MAIN SFC RIDGE AXIS ACRS CENTRAL INTO EASTERN IA BY 00Z FRI
MAKING FOR SOME CLOUD CLEAR OUT AS THU PROGRESSES. HIGHS ONLY TO
RECOVER INTO THE SINGLE DIGITS ABOVE ZERO IN MUCH OF THE CWA. THEN
THE STAGE WILL BE SET FOR A NEAR RECORD COLD ARCTIC NIGHT THU NIGHT
INTO FRI MORNING AND AGAIN WILL SIDE WITH THE MUCH COLDER MAV MOS
GUIDANCE VALUES. CID MAY HAVE THE BEST CHC OF BREAKING IT/S RECORD
FOR THE 3RD OF JAN BEING -15F. ALTHOUGH THE WINDS SHOULD BE
DECOUPLING...EVEN 5 KT WINDS WILL PRODUCE SOLID WIND CHILL ADVISORY
AND POSSIBLE EVEN SOME WIND CHILL WARNING CRITERIA LATE THU NIGHT
AFTER 06Z INTO MID FRI MORNING.
FRIDAY THROUGH SUNDAY...ARCTIC RIDGE PROGGED TO MIGRATE OFF TO THE
EAST ON FRI WHICH WILL ALLOW RATHER ROBUST LLVL SOUTHERLY RETURN FLOW
TO BRING ABOUT A SUBSTANTIAL SFC TEMP MODERATION. AFTER SUCH A
FRIGID START TO THE MORNING...12 HR HIGHS WILL OCCUR AT AROUND 00Z
SAT...AND 24 HR HIGHS PROBABLY THROUGH MIDNIGHT FRI NIGHT. THE
LATEST RUN MEDIUM RANGE SOLUTIONS THEN SUGGEST TEMPORARY
FLATTENING FLOW PATTERN TO USHER A MORE VIGOROUS WAVE ACRS THE
NORTHERN PLAINS INTO THE NORTHWESTERN GRT LKS INTO SAT MORNING. WAA
SHIELD OF PRECIP ASSOCIATED WITH THIS FEATURE SHOULD STAY TO THE
NORTH OF THE CWA FRI NIGHT. DISCREPANCIES POP UP WITH THIS SYSTEM/S
SFC FROPA THROUGH THE CWA BY SAT AFTERNOON. THE 12Z ECMWF MAINTAINS
A DRY FROPA...WHILE THE 12Z GFS HAS TRENDED WETTER WITH POST FRONTAL
BAN OF SNOWS ACRS AT LEAST THE NORTHWESTERN THIRD OF THE CWA SAT
AFTERNOON...POSSIBLY 1-3 INCHES OF SNOW ACCUM BY EARLY SAT
EVENING. WILL KEEP SLIGHT CHC TO CHC POPS GOING FOE EXPECTING THE
ECMWF TO TREND WETTER AND PRODUCE SOME PRECIP IN THE CWA. BEFORE
FROPA...MILDEST DAY IN THE PERIOD SAT WITH HIGHS IN THE MID 20S IN
THE NORTH...TO THE LOWER 30S IN THE SOUTH. WOULD BE WARMER IF IT
WERE NOT FOR THE SNOWPACK. RE-ESTABLISHING L/W TROF BASE SOMEWHERE
ACRS THE MID CONUS AND PROBABLY WEST OF OF THE MS RVR VALLEY...AND
WAVE ENERGY EJECTING OUT OF THE DEEP PLAINS LATE SAT NIGHT AND INTO
SUNDAY WILL BE A WINDOW TO WATCH FOR FURTHER NORTHWEST PULL OUT
PATHWAY. RIGHT NOW THE LATEST GFS/ECMWF AND ENSEMBLES JUST CLIP THE
FAR SOUTHERN AND SOUTHEASTERN CWA WITH 1-2+ INCHES BY SUNDAY
AFTERNOON. NORTHERLY LLVL COLD CONVEYOR WRAPPING IN AROUND THIS
FEATURE TO BRING ABOUT COLDER TEMPS AGAIN SAT NIGHT AND SUNDAY.
THEN BULK OF THE MEDIUM RANGE MODELS CONTINUE TO ADVERTISE A HUGELY
NEGATIVE ANOMALY IN THEIR L/W TROF FORMATION ACRS THE UPPER AND MID
MS RVR VALLEY BY 12Z MON. SEEMS THE POLAR VORTEX GYRATING ACRS THE
SOUTHERN HUDSON BAY REGION REMAINS TRAPPED AND ACTING AS A TYPE OF
BLOCK FOR RIDGING OFF THE COASTS.
NEXT MONDAY AND TUESDAY...THE 12Z GFS HAD AN INCREDIBLY INTENSE SFC
HIGH OF 1058 MB INTO NORTH CENTRAL MT BY 12Z MON...WITH THE RIDGE
CENTER THEN MODERATING TO THE LOWER 1040S AS IT SLIDES SOUTHEASTWARD
ACRS THE REGION FOR MON NIGHT INTO TUE MORNING. THE EURO NOT QUITE
SO STRONG WITH A 1045 MB HIGH...BUT THEY BOTH ADVERTISE ARCTIC DOME
OF AIR TO SURGE ACRS THE CWA/FROPA AS MONDAY PROGRESSES. SHARPLY
DROPPING TEMPS...AND IF THE MODEL PROGGED -26C TO -28C H85 MB
AIRMASS VERIFIES AND MAKE IT ACRS THE CWA...COULD BE SOME -15 TO
-25F LOW TEMPS BY TUE MORNING IN PORTIONS OF THE DVN CWA. INCREDIBLE
COLD. WILL IT MODERATE THEN MID TO LATE NEXT WEEK AS BULK OF THE
MEDIUM RANGE SOLUTIONS SUGGEST...OR THEY CONTINUE TO MISHANDLE SUCH
A NEG ANOMALY REGIME AND OPEN THE REGION/MIDWEST BACK TO MORE ARCTIC
DUMPS AFTER NEXT WED. ..12..
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1140 AM CST TUE DEC 31 2013
A CHALLENGING WINTER STORM WILL BRING SNOW TO NORTHERN IOWA AND
NORTHERN ILLINOIS THIS AFTERNOON THROUGH WEDNESDAY AFTERNOON...AND
TO THE REMAINDER OF THE AREA LATE THIS EVENING THROUGH WEDNESDAY
EVENING. THIS WILL BE DOMINATED BY MVFR CIGS AROUND 1200 TO 2500
FT...AND IFR VISIBILITY AROUND 1 TO 3 MILES IN SNOW AND FOG. SOME
PERIODS OF LIFR ARE POSSIBLE TODAY AND THIS EVENING AT DBQ WHERE
THE HEAVIEST SNOW SHOULD OCCUR. ANOTHER PERIOD OF MODERATE SNOW IS
POSSIBLE AT CID AND MLI WEDNESDAY DURING THE DAY...AND THEN AT
BURLINGTON WEDNESDAY LATE MORNING AND AFTERNOON. THIS WILL BE
BETTER DEFINED IN FUTURE TAFS AS WE APPROACH THIS EVENT. WINDS
WILL BE LIGHT INITIALLY...BUT SHOULD BECOME NORTHEASTERLY AT ALL
SITES LATE THIS AFTERNOON THROUGH WEDNESDAY.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR BENTON-
BUCHANAN-DELAWARE-DUBUQUE-JACKSON-JONES-LINN.
WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM CST WEDNESDAY FOR
CEDAR-DES MOINES-HENRY IA-IOWA-JEFFERSON-JOHNSON-KEOKUK-
LOUISA-MUSCATINE-SCOTT-WASHINGTON.
WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR CLINTON.
IL...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR JO DAVIESS-
STEPHENSON.
WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM CST WEDNESDAY FOR
BUREAU-HENRY IL-MERCER-PUTNAM-ROCK ISLAND.
WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR CARROLL-
WHITESIDE.
MO...NONE.
&&
$$
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...12
AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1226 PM EST TUE DEC 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EST TUE DEC 31 2013
WV IMAGERY AND RUC ANALYSIS INDICATED CYCLONIC WNW MID/UPPER LEVEL
FLOW INTO THE NRN GREAT LAKES AROUND THE POLAR VORTEX LOCATED OVER
SRN HUDSON BAY. A SHORTWAVE TROUGH EXTENDING FROM LAKE SUPERIOR TO
INDIANA WAS SLIDING QUICKLY TO THE EAST AS A SFC RIDGE OR ARCTIC
HIGH PRES BUILDS FROM SASK AND THE NRN PLAINS INTO THE UPPER MS
VALLEY. VEERING LOW LEVEL WINDS TO WNW AND VERY COLD AIR WITH 850 MB
TEMPS FROM -21C TO -25C SUPPORTED LES BANDS INTO THE KEWEENAW AND
THE NE CWA. KMQT AND MONTREAL RIVER RADARS INDICATED THAT THE
HEAVIEST LES ASOCIATED WITH A TROUGH OR WEAK MESO LOW OVER SE LAKE
SUPERIOR HAD SHIFTED INTO NW LUCE COUNTY. SATELLITE AND WEB CAMS
OVER THE KEWEENAW SUGGEST THAT THE HEAVIER LES FROM MON AFTERNOON
AND EVENING HAD DIMINISHED AS LES TRANSITIONS TOWARD MULTIPLE WEAKER
BANDS. CLEARING OVER INLAND LOCATIONS HAS ALLOWED TEMPS TO DROP TO
AROUND -25F AT WAKEFIELD AND LANDOLAKES WHERE WINDS WERE CALM. WINDS
IN THE TO 10 MPH RANGE MOST LOCATIONS IN THE INTERIOR WEST COMBINED
WITH TEMPS IN THE -8 TO -15 RANGE HAS PUSHED WIND CHILLS INTO THE
-20 TO -30 RANGE.
TODAY...THE HIGH RES MODELS SUGGEST THAT THE STRONGEST LOW LEVEL
CONV SUPPORTED BY THE LAKE INDUCED TROUGHING OVER SE LAKE SUPERIOR
WILL GRADUALLY SHIFT TO THE EAST AS NW WINDS INCREASE ACROSS LAKE
SUPERIOR. WITH ENOUGH OF THE DGZ IN THE CONVECTIVE LAYER...SLR
VALUES SHOULD BE HIGH ENOUGH TO SUPPORT OVERALL SNOWFALL TOTALS IN
THE 4 TO 8 INCH RANGE...WITH SOME ISOLATED GREATER AMOUNTS POSSIBLE
WITH THE GREATEST AMOUNTS FROM GRAND MARAIS TO PINE STUMP JCT AND
CRISP POINT. OVER THE WEST...THE GREATEST LOW LEVEL CONV BETWEEN
HOUGHTON AND TWIN LAKES IS EXPECTED TO WEAKEN WITH NW FLOW ACROSS
THE SHORT AXIS OF THE WRN LAKE. ADDITIONAL AMOUNTS IN THE 1 TO 3
INCH RANGE ARE EXPECTED WITH THE GREATEST AMOUNTS THIS MORNING.
TONIGHT...AS THE ARCTIC RIDGE BUILDS INTO NRN ONTARIO...MODELS
SUGGEST THAT THE LOW LEVEL WINDS WILL CONTINUE TO VEER AND WEAKEN.
AS A RESULT THE LAKE INDUCED TROUGH OVER THE ERN LAKE AND BEST LOW
LEVEL CONV IS EXPECTED TO SHIFT BACK TO THE WEST. HOWEVER...THE
LOCATION OF ANY HEAVIER SNOWBANDS IS LESS CERTAIN. SO...2 TO 5 INCH
AMOUNTS MAY BE POSSIBLE BETWEEN MUUNSING AND NRN LUCE COUNTY. WITH
MORE ACYC FLOW OVER THE WEST AND INVERSION HEIGHTS DROPPING TO
AROUND 4K FT...MAINLY 1 TO 2 INCH AMOUNTS ARE EXPECTED. EVEN THOUGH
TEMPS WILL DROP OFF AGAIN TO -15 TO -20 OVER THE INLAND WEST...LIGHTER
WINDS AT OR BELOW 5 MPH SHOULD REDUCE THE SEVERITY OF WIND
CHILLS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 539 AM EST TUE DEC 31 2013
WILL START OFF WEDNESDAY MORNING WHERE WE ARE ALL TOO FAMILIAR
WITH...UNDER A BROAD 500MB TROUGH. THE CENTER OF THE LOW WILL BE
OVER CENTRAL QUEBEC...WITH A TROUGH EXTENDING SE ACROSS THE N PLAINS
AND INTO THE 4-CORNERS REGION. A DISTURBANCE TRACKING TO OUR S LOOKS
TO BE TOO FAR AWAY TO DO MUCH FOR OUR WX UP N...SO GOT RID OF THE
SLIGHT CHANCE POPS THAT WERE BLANKETING S CENTRAL UPPER MI WEDNESDAY.
THE COLD SNAP WILL LINGER THROUGH THURSDAY...BEFORE SLOWLY
MODERATING FRIDAY AND SATURDAY. WILL WILL CONTINUE TO BE IN A
DIFFICULT POSITION...WHERE TEMPERATURES WILL BE VERY COLD...BUT
WINDS WILL BE BORDERLINE OR WELL BELOW WIND CHILL ADVISORY CRITERIA
/10MPH/.
MUCH OF OUR WX IN THE MID RANGE OF THE FCST PERIOD WILL BE DOMINATED
BY THE WEAKENING BY STILL PERSISTENT SFC LOW/TROUGH WEAKENING ACROSS
E LAKE SUPERIOR AND E UPPER MI. WHILE THE STRONG HIGH OVER MN IS
ABLE TO TO DISRUPT THE LES OVER FAR W UPPER MI WEDNESDAY AND
WEDNESDAY NIGHT...PERSISTENT N TO NW FLOW SHOULD KEEP A HEALTHY BAND
OR MORE LIKELY MULTI-BAND LES GOING E OF MARQUETTE THROUGH
MUNISING...AND E OF MUNISING NEAR LAKE SUPERIOR.
FOR LATE THURSDAY AFTERNOON THROUGH THURSDAY NIGHT...THE EVER
WEAKENING SFC TROUGH OUT E WILL FINALLY LOSE OUT...WITH THE 500MB
TROUGH EXITING E TO THE LOWER GREAT LAKES. LIGHT AND MORE VARIABLE
NEAR-SFC WINDS SHOULD PUSH LIGHT/MODERATE LES BANDS OFF INTO LAKE
SUPERIOR.
CONTINUED AN ATTEMPT TO ADD SOME BETTER TIMING TO THE LONGER TERM
POPS/WX FOR FRIDAY ON. MODELS ARE CONSISTENT ON BRINGING THE 500MB
RIDGE ACROSS THE UPPER GREAT LAKES FRIDAY...WITH THE NEXT LOW OVER
CENTRAL CANADA POISED TO SINK SE AND DOMINATE OUR WX FOR THROUGH AT
LEAST EARLY NEXT WEEK.
BROUGHT THE STRONG SW WINDS MORE TO THE GREAT LAKES SHORELINES
FRIDAY/SATURDAY...AS THE LARGER SCALE MODELS TYPICALLY HAVE A
DIFFICULT TIME WITH THIS. GALES WILL BE POSSIBLE OVER LAKE MI...AND
E LAKE SUPERIOR LATE FRIDAY AFTERNOON THROUGH EARLY SATURDAY
MORNING. BLOWING SNOW WAS ALSO INTRODUCED...MAINLY CENTRAL AND E
NEAR THE GREAT LAKES. 45-55KT WINDS AT 850MB ARE STILL BEING SHOWN
18Z FRIDAY TO AROUND 12Z SATURDAY. MODEL DISCREPANCIES REMAIN IN THE
TIMING OF THE SFC LOW AND ITS ASSOCIATED COLD FRONT...ALTHOUGH MUCH
MORE IN LINE THAN 24HRS AGO. EXPECT THE
A BURST OF HEAVY WET SNOW WILL BE POSSIBLE ACROSS MUCH OF THE CWA IF
THE GFS IS CORRECT. WILL GO CLOSER TO THE 31/00Z ECMWF AT THIS POINT
WITH THE BULK OF THE ENERGY SLIDING ACROSS THE N HALF OF THE
AREA...WITH LES COMING BACK IN BEHIND THE PASSAGE OF THE COLD FRONT
SATURDAY MORNING. WITH THE COLD AIR RAPIDLY SWINGING BACK IN ON W TO
NW WINDS SATURDAY AFTERNOON INTO EARLY SUNDAY...EXPECT A BRIEF
MOMENT OF LAKE ENHANCED SNOW ACROSS THE KEWEENAW PENINSULA.
HIGHLIGHTED THE POTENTIAL IN THE HWO/EHWO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1226 PM EST TUE DEC 31 2013
KIWD...AS WINDS GO TO THE WNW...EXPECT SOME LAKE EFFECT CLOUDS AND
LIGHT SNOW SHOWERS WILL CONTINUE THIS AFTERNOON THROUGH THE PERIOD
WITH MVFR CONDITIONS EXPECTED.
KCMX...WITH STRONG GUSTY WINDS THIS AFTERNOON...BLOWING SNOW WILL
CONTINUE TO CAUSE VLIFR CONDITIONS. AS THE WINDS DIE DOWN BY THIS
EVENING...CONDITIONS WILL IMPROVE FROM IFR TO MVFR.
SAW...VFR CONDITIONS WILL CONTINUE THROUGH TONIGHT WITH DOWNSLOPE
WINDS. AS WINDS GO NORTHERLY WED MORNING...LAKE EFFECT SNOW SHOWERS
WILL MOVE BACK IN WITH MVFR CONDITIONS EXPECTED.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 349 AM EST TUE DEC 31 2013
HEAVY FREEZING SPRAY WILL REMAIN A CONCERN FOR MAINLY CENTRAL AND
EASTERN LAKE SUPERIOR THROUGH EARLY WEDESDAY...AS AIR TEMPS CONTINUE TO
BE IN THE TEENS ABOVE ZERO TO THE SINGLE DIGITS BELOW ZERO...AND NW
TO N WINDS IN THE 20-30KT RANGE.
STRONG HIGH PRESSURE OVER SASKATCHEWAN WILL BUILD INTO MINNESOTA
TONIGHT...AND REMAIN NEARLY STATIONARY THROUGH THURSDAY.
OTHERWISE...THE PESKY LOW/TROUGH STRETCHING FROM EASTERN LAKE
SUPERIOR TO ALL OF SOUTHEASTERN ONTARIO WILL EXIT EASTWARD
TODAY...LEAVING A WEAKENING TROUGH ACROSS LAKE SUPERIOR THAT WILL
LINGER THROUGH THURSDAY...AS THE HIGH PRESSURE SYSTEM TO OUR WEST
SINKS INTO THE MID MISSISSIPPI VALLEY. EXPECT LOW PRESSURE ALONG THE
CENTRAL U.S./CANADIAN BORDER FRIDAY TO CROSS LAKE SUPERIOR AND
ONTARIO ON SATURDAY. AHEAD OF THIS LOW...S GUSTS OF 25-30KTS LATE
FRIDAY AFTERNOON INTO SATURDAY MORNING MAY JUMP UP TO GALES
/PARTICULARLY ACROSS E LAKE SUPERIOR FRIDAY NIGHT/.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ001-
003-006-007-085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST
WEDNESDAY FOR LSZ267.
HEAVY FREEZING SPRAY WARNING UNTIL 9 AM EST WEDNESDAY FOR LSZ243-
244-264-266.
HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST WEDNESDAY FOR LSZ248-
265.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
WEDNESDAY FOR LSZ241-242-263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ249-
250.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...KF
AREA FORECAST DISCUSSION
NWS BILLINGS MT
1230 PM MST TUE DEC 31 2013
.UPDATE...
ISSUING A QUICK UPDATE THIS AFTERNOON TO ISSUE A WINTER WEATHER
ADVISORY FOR SNOW...FREEZING RAIN...AND VERY SLICK ROADS FOR MUCH
OF THE CWA. HAVE ALREADY GOTTEN REPORTS OF RAINFALL...AND
ACCUMULATING SNOWS...WHICH IS BOUND TO CREATE VERY SLICK ROADS
ACROSS MUCH OF THE REGION. HAVE OPTED TO START INHERITED
ADVISORIES EARLY AND EXTEND THE ENDING TIME THROUGH WEDNESDAY
EVENING TO COVER LINGERING SNOWS ON ALREADY SLICK ROAD CONDITIONS.
CHANGES TO GRIDS CENTERED AROUND INCREASING SNOW AMOUNTS ACROSS
THE REGION. AAG
&&
.SHORT TERM...VALID FOR TDY AND WED...
ACTIVE WEATHER COMING IN THE SHORT TERM WITH BOTH
WIND AND SNOW CONCERNS.
FIRST WIND. LIVINGSTON HAS BEEN HITTING ADVISORY GUSTS FOR SEVERAL
HOURS AND WILL MAKE NO CHANGE TO THE HIGHLIGHT IN PLACE. LEE SIDE
PRESSURE RISES ARE BEGINNING TO REDUCE THE GRADIENT SLOWLY...BUT
WOULD EXPECT HIGH GUSTS TO CONTINUE FOR MUCH OF THE DAY AS SFC
TROF REMAINS IN CENTRAL MT. COULD SEE GUSTS AS HIGH AS 50 MPH AT
BIG TIMBER AND THE BEARTOOTH FOOTHILLS BUT ORIENTATION OF GRADIENT
SHOULD FAVOR LVM MOST TODAY. COLD ADVECTION FROM THE NW SHOULD END
THE HIGHER GAP FLOW GUSTS BY THIS EVENING.
NOW SNOW. SHORTWAVE EMBEDDED IN NW FLOW ALOFT PUSHING INTO
EASTERN MT IS PRODUCING SOME SNOW ACROSS OUR EAST. MOST
INTERESTING FEATURE IS HEAVIER BAND DROPPING INTO NORTHERN
ROSEBUD AND CUSTER COUNTIES AT 10Z...WHICH IS IN REGION OF STRONG
850MB FRONTOGENESIS. EXPECT A BURST OF FAIRLY HEAVY SNOW OVER THE
NEXT FEW HOURS FROM MILES CITY TO BAKER AND EKALAKA...WITH 1 TO 2
INCHES LIKELY BEFORE THE PCPN DIMINISHES BY AROUND SUNRISE.
FURTHER WEST...STRONG DOWNSLOPE WINDS WILL KEEP LOCATIONS FROM
BILLINGS WEST DRY THIS MORNING. CURRENT TEMPERATURE GRADIENT
ACROSS OUR CWA IS IMPRESSIVE WITH BALMY TEMPS AROUND 40F TO OUR
WEST AND ONLY THE LOW TEENS IN OUR EAST.
STRONGER SHORTWAVE ALONG THE NORTHWEST BC COAST WILL PUSH TOWARD
OUR REGION LATER TODAY...WITH FAIRLY STRONG Q-VECTOR CONVERGENCE
EXPECTED TO BEGIN AROUND 00Z. INTERACTION WITH LOW LEVEL SFC
FRONT IS CRITICAL FOR THE PCPN FORECAST FOR TONIGHT. GFS/ECMWF ARE
CONSISTENT IN BRINGING THIS BOUNDARY AS FAR WEST AS BILLINGS AND
SHERIDAN BY 00Z...WHEREAS THE NAM AND RAP ARE SLOWER. UPSTREAM...
NOTE THAT CUT BANK HAS SHIFTED TO THE NE OVER THE PAST COUPLE
HOURS IN RESPONSE TO SLIGHT PRESSURE RISES BUILDING INTO NORTH
CENTRAL MT. GIVEN THIS IN ADDITION TO EAST WINDS AROUND 20 MPH AT
MLS AND BHK ARE STRONGER THAN ANY GUIDANCE SUGGESTS...BELIEVE THE
GFS/EC ARE CORRECT WITH THE FASTER SOUTHWESTWARD EVOLUTION OF
THIS BOUNDARY TODAY. THAT BEING SAID...AFTER THE MORNING SNOW IN
OUR EAST...PCPN SHOULD INCREASE AGAIN THIS AFTERNOON IN RESPONSE
TO INCREASING DEEP LAYER ASCENT...WITH FOCUS OF LOW LEVEL
FRONTOGENESIS AND PCPN SHIFTING TO THE WEST OVER TIME...AND LIKELY
GETTING TO AS FAR WEST AS BILLINGS AND SHERIDAN BY LATE
AFTERNOON. HAVE ADDED THIS DETAIL IN THE WIND AND POP GRIDS.
OUR CENTRAL PARTS SEEM POISED FOR A SNOW EVENT TONIGHT AS NW WAVE
COMES THROUGH. MUST NOTE THAT MID LEVEL LAPSE RATES EXPECTED TO BE
QUITE STEEP...ABOVE 7C/KM FROM 700-500MB...SO EXPECT SOME HEAVY
SNOW ALONG A FRONTOGENETIC BAND...WHICH MAY BE ADDITIONALLY
ENHANCED BY CONVERGENCE IN THE LEE OF THE SNOWIES. TOUGH TO
FIGURE WHERE EXACTLY THIS MIGHT SET UP...BUT BILLINGS IS A
POSSIBILITY. GREATEST CONFIDENCE FOR SEVERAL INCHES OF SNOW IS IN
OUR NW UPSLOPE AREAS TO THE SE OF BILLINGS...IE BIG HORN AND
SHERIDAN COUNTIES. WILL ISSUE ADVISORIES FROM TONIGHT INTO
WEDNESDAY FOR THIS AREA. SFC BOUNDARY SHOULD HANG UP ALONG THE
EAST SIDE OF THE BIG HORN MTNS TONIGHT...SO EXPECT FAIRLY LIGHT
WINDS IN SHERIDAN ITSELF SO COULD BE A GOOD SNOW EVENT THERE.
OVERALL AM THINKING 3-6 INCHES FOR THE FOOTHILLS AND 6-12 OVER THE
BIG HORNS...WHICH ARE OBVIOUSLY FAVORED IN THE MOIST AND UNSTABLE
NW FLOW. SECONDARY PV MAX ROTATES SOUTH INTO EARLY WEDNESDAY SO
WILL TAKE ADVISORY ALL THE WAY TO NOON TOMORROW.
OUR WESTERN LOWER ELEVATIONS WILL SEE VERY LITTLE SNOW DUE TO
PERSISTENT DOWNSLOPE WINDS. WESTERN SLOPES OF THE BEARTOOTH
ABSAROKA AND CRAZY MTNS WILL DO QUITE WELL THOUGH...ON THE ORDER
OF 6-12 INCHES...THOUGH DO NOT SEE A LONG ENOUGH DURATION EVENT TO
WARRANT A WARNING...ESPECIALLY CONSIDERING THE MID LEVEL WINDS
WILL VEER FROM WEST TO NORTHWEST OVER TIME THUS SHIFTING THE
ASPECTS ON WHICH THE HEAVIEST AMTS WILL FALL.
TEMPS TODAY AND TOMORROW WILL CONTINUE TO BE WARMEST IN OUR WEST
AND COLDEST IN OUR EAST...WITH 30 DEGREES OR MORE OF DIFFERENCE.
AS WEDNESDAY SYSTEM DEPARTS WE WILL SEE A RETURN OF ANTICYCLONIC
FLOW ALOFT AND LEE SIDE SFC TROFFING BY WEDNESDAY NIGHT. LOOKS
LIKE POTENTIAL ADVISORY GUSTS ONCE AGAIN AT LIVINGSTON BY LATE
WEDNESDAY NIGHT.
JKL
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
SOME SIGNIFICANT CHANGES TO THE EXTENDED FOR THIS PACKAGE REVOLVE
AROUND THE POTENTIAL ARCTIC SURGE WE WERE LOOKING AT EARLY NEXT
WEEK. THE ECMWF HAS COMPLETELY GONE AWAY FROM THIS SCENARIO
BY BRINGING THE PACIFIC RIDGE FURTHER INLAND THAN THE GFS THEREBY
DEFLECTING THE ARCTIC AIR EASTWARD TO THE DAKOTAS...WHILE THE GFS
HAS THE COLD AIR ENTRENCHED UP AGAINST THE DIVIDE. THE 12Z ECMWF
STARTED HINTING AT THIS TREND SO THE 00Z ECMWF IS NOT A SURPRISE.
ENSEMBLE SPREADS ARE NOT QUITE AS WIDE AS THE 12Z RUN OF THE
ECMWF. OUR EXTREME FORECAST INDEX POINTS TO THE DAKOTAS AS WHERE
THE BULK OF THE COLDEST AIR WILL GO AS WELL. IN ORDER TO REMOVE
THE RISK OF LARGE FORECAST ERRORS WE WILL TREND THE FORECAST TO A
BLEND DOMINATED BY THE ECMWF...THUS INCREASING OUR TEMPERATURE
FORECASTS QUITE A BIT FOR EARLY NEXT WEEK ACROSS MAINLY OUR
WESTERN ZONES. HOWEVER...WE WILL REMAIN LEARY OF A POTENTIAL
SWITCH IN THE ECMWF. CHANGES WILL ALSO BE REFLECTED BY LOWERING
POPS A BIT FOR EARLY NEXT WEEK. BT
&&
.AVIATION...
STRONG SOUTHWEST WINDS WILL CONTINUE AT LIVINGSTON THIS MORNING
WITH GUSTS OVER 50 KNOTS AT TIMES. THESE WINDS WILL DECREASE BY
18Z. AREAS OF LIGHT SNOW CAUSING MVFR TO IFR CONDITIONS WILL
CONTINUE FROM MILES CITY EASTWARD BEFORE IMPROVING BY 00Z. SOUTH
CENTRAL MONTANA FROM BILLINGS WEST WILL HAVE LOWERING CEILINGS AND
AREAS OF SNOW DEVELOPING AFTER 18Z TODAY. THESE CONDITIONS WILL
SPREAD INTO LIVINGSTON AND SHERIDAN THIS EVENING. MVFR TO LOCAL
LIFR CONDITIONS WILL BE POSSIBLE AS WELL AS MOUNTAIN OBSCURATIONS.
RICHMOND
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 040 021/032 020/042 030/048 020/029 017/016 904/014
7/W 95/J 00/B 03/W 31/B 13/S 32/J
LVM 041 027/036 028/043 033/046 017/029 012/021 901/019
5/W 62/J 01/N 03/W 31/B 23/S 22/J
HDN 039 017/030 014/035 024/046 014/028 011/016 908/012
7/S 96/S 00/B 03/W 31/B 23/S 32/J
MLS 014 005/019 006/028 020/042 012/022 008/008 915/004
8/S 74/S 10/B 04/W 42/B 34/S 21/B
4BQ 032 013/026 005/032 021/046 015/024 011/014 911/010
8/S 85/S 10/B 03/W 41/B 24/S 32/J
BHK 011 000/013 903/026 018/043 012/019 003/005 916/000
8/S 74/S 10/B 04/W 51/B 23/S 21/B
SHR 041 018/030 011/040 022/049 015/027 011/019 906/016
5/W 97/S 00/B 02/W 32/B 24/S 32/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 PM MST WEDNESDAY
FOR ZONES 28>38-41-42-57-58-63.
WIND ADVISORY IN EFFECT UNTIL 5 PM MST THIS AFTERNOON FOR
ZONE 65.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 PM MST WEDNESDAY
FOR ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
916 AM MST TUE DEC 31 2013
.UPDATE...
MINOR UPDATE THIS MORNING TO ADJUST SOME OF THE TEMPERATURES IN
THE EAST DOWNWARD. WE HAVE ALREADY HIT THE HIGH TEMPERATURE FOR
THE DAY ACROSS MUCH OF THE REGION...AS A BACKDOOR COLD FRONT SAGS
INTO THE REGION. WE ARE CURRENTLY WATCHING VERY CLOSELY WHERE THE
FRONT MANAGES TO BACK INTO...AS THIS WILL LIKELY BE THE BEST
POTENTIAL FOR AN AREA OF HEAVIER SNOW TONIGHT. AAG
&&
.SHORT TERM...VALID FOR TDY AND WED...
ACTIVE WEATHER COMING IN THE SHORT TERM WITH BOTH WIND AND SNOW
CONCERNS.
FIRST WIND. LIVINGSTON HAS BEEN HITTING ADVISORY GUSTS FOR SEVERAL
HOURS AND WILL MAKE NO CHANGE TO THE HIGHLIGHT IN PLACE. LEE SIDE
PRESSURE RISES ARE BEGINNING TO REDUCE THE GRADIENT SLOWLY...BUT
WOULD EXPECT HIGH GUSTS TO CONTINUE FOR MUCH OF THE DAY AS SFC
TROF REMAINS IN CENTRAL MT. COULD SEE GUSTS AS HIGH AS 50 MPH AT
BIG TIMBER AND THE BEARTOOTH FOOTHILLS BUT ORIENTATION OF GRADIENT
SHOULD FAVOR LVM MOST TODAY. COLD ADVECTION FROM THE NW SHOULD END
THE HIGHER GAP FLOW GUSTS BY THIS EVENING.
NOW SNOW. SHORTWAVE EMBEDDED IN NW FLOW ALOFT PUSHING INTO
EASTERN MT IS PRODUCING SOME SNOW ACROSS OUR EAST. MOST
INTERESTING FEATURE IS HEAVIER BAND DROPPING INTO NORTHERN
ROSEBUD AND CUSTER COUNTIES AT 10Z...WHICH IS IN REGION OF STRONG
850MB FRONTOGENESIS. EXPECT A BURST OF FAIRLY HEAVY SNOW OVER THE
NEXT FEW HOURS FROM MILES CITY TO BAKER AND EKALAKA...WITH 1 TO 2
INCHES LIKELY BEFORE THE PCPN DIMINISHES BY AROUND SUNRISE.
FURTHER WEST...STRONG DOWNSLOPE WINDS WILL KEEP LOCATIONS FROM
BILLINGS WEST DRY THIS MORNING. CURRENT TEMPERATURE GRADIENT
ACROSS OUR CWA IS IMPRESSIVE WITH BALMY TEMPS AROUND 40F TO OUR
WEST AND ONLY THE LOW TEENS IN OUR EAST.
STRONGER SHORTWAVE ALONG THE NORTHWEST BC COAST WILL PUSH TOWARD
OUR REGION LATER TODAY...WITH FAIRLY STRONG Q-VECTOR CONVERGENCE
EXPECTED TO BEGIN AROUND 00Z. INTERACTION WITH LOW LEVEL SFC
FRONT IS CRITICAL FOR THE PCPN FORECAST FOR TONIGHT. GFS/ECMWF ARE
CONSISTENT IN BRINGING THIS BOUNDARY AS FAR WEST AS BILLINGS AND
SHERIDAN BY 00Z...WHEREAS THE NAM AND RAP ARE SLOWER. UPSTREAM...
NOTE THAT CUT BANK HAS SHIFTED TO THE NE OVER THE PAST COUPLE
HOURS IN RESPONSE TO SLIGHT PRESSURE RISES BUILDING INTO NORTH
CENTRAL MT. GIVEN THIS IN ADDITION TO EAST WINDS AROUND 20 MPH AT
MLS AND BHK ARE STRONGER THAN ANY GUIDANCE SUGGESTS...BELIEVE THE
GFS/EC ARE CORRECT WITH THE FASTER SOUTHWESTWARD EVOLUTION OF
THIS BOUNDARY TODAY. THAT BEING SAID...AFTER THE MORNING SNOW IN
OUR EAST...PCPN SHOULD INCREASE AGAIN THIS AFTERNOON IN RESPONSE
TO INCREASING DEEP LAYER ASCENT...WITH FOCUS OF LOW LEVEL
FRONTOGENESIS AND PCPN SHIFTING TO THE WEST OVER TIME...AND LIKELY
GETTING TO AS FAR WEST AS BILLINGS AND SHERIDAN BY LATE
AFTERNOON. HAVE ADDED THIS DETAIL IN THE WIND AND POP GRIDS.
OUR CENTRAL PARTS SEEM POISED FOR A SNOW EVENT TONIGHT AS NW WAVE
COMES THROUGH. MUST NOTE THAT MID LEVEL LAPSE RATES EXPECTED TO BE
QUITE STEEP...ABOVE 7C/KM FROM 700-500MB...SO EXPECT SOME HEAVY
SNOW ALONG A FRONTOGENETIC BAND...WHICH MAY BE ADDITIONALLY
ENHANCED BY CONVERGENCE IN THE LEE OF THE SNOWIES. TOUGH TO
FIGURE WHERE EXACTLY THIS MIGHT SET UP...BUT BILLINGS IS A
POSSIBILITY. GREATEST CONFIDENCE FOR SEVERAL INCHES OF SNOW IS IN
OUR NW UPSLOPE AREAS TO THE SE OF BILLINGS...IE BIG HORN AND
SHERIDAN COUNTIES. WILL ISSUE ADVISORIES FROM TONIGHT INTO
WEDNESDAY FOR THIS AREA. SFC BOUNDARY SHOULD HANG UP ALONG THE
EAST SIDE OF THE BIG HORN MTNS TONIGHT...SO EXPECT FAIRLY LIGHT
WINDS IN SHERIDAN ITSELF SO COULD BE A GOOD SNOW EVENT THERE.
OVERALL AM THINKING 3-6 INCHES FOR THE FOOTHILLS AND 6-12 OVER THE
BIG HORNS...WHICH ARE OBVIOUSLY FAVORED IN THE MOIST AND UNSTABLE
NW FLOW. SECONDARY PV MAX ROTATES SOUTH INTO EARLY WEDNESDAY SO
WILL TAKE ADVISORY ALL THE WAY TO NOON TOMORROW.
OUR WESTERN LOWER ELEVATIONS WILL SEE VERY LITTLE SNOW DUE TO
PERSISTENT DOWNSLOPE WINDS. WESTERN SLOPES OF THE BEARTOOTH
ABSAROKA AND CRAZY MTNS WILL DO QUITE WELL THOUGH...ON THE ORDER
OF 6-12 INCHES...THOUGH DO NOT SEE A LONG ENOUGH DURATION EVENT TO
WARRANT A WARNING...ESPECIALLY CONSIDERING THE MID LEVEL WINDS
WILL VEER FROM WEST TO NORTHWEST OVER TIME THUS SHIFTING THE
ASPECTS ON WHICH THE HEAVIEST AMTS WILL FALL.
TEMPS TODAY AND TOMORROW WILL CONTINUE TO BE WARMEST IN OUR WEST
AND COLDEST IN OUR EAST...WITH 30 DEGREES OR MORE OF DIFFERENCE.
AS WEDNESDAY SYSTEM DEPARTS WE WILL SEE A RETURN OF ANTICYCLONIC
FLOW ALOFT AND LEE SIDE SFC TROFFING BY WEDNESDAY NIGHT. LOOKS
LIKE POTENTIAL ADVISORY GUSTS ONCE AGAIN AT LIVINGSTON BY LATE
WEDNESDAY NIGHT.
JKL
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
SOME SIGNIFICANT CHANGES TO THE EXTENDED FOR THIS PACKAGE REVOLVE
AROUND THE POTENTIAL ARCTIC SURGE WE WERE LOOKING AT EARLY NEXT
WEEK. THE ECMWF HAS COMPLETELY GONE AWAY FROM THIS SCENARIO
BY BRINGING THE PACIFIC RIDGE FURTHER INLAND THAN THE GFS THEREBY
DEFLECTING THE ARCTIC AIR EASTWARD TO THE DAKOTAS...WHILE THE GFS
HAS THE COLD AIR ENTRENCHED UP AGAINST THE DIVIDE. THE 12Z ECMWF
STARTED HINTING AT THIS TREND SO THE 00Z ECMWF IS NOT A SURPRISE.
ENSEMBLE SPREADS ARE NOT QUITE AS WIDE AS THE 12Z RUN OF THE
ECMWF. OUR EXTREME FORECAST INDEX POINTS TO THE DAKOTAS AS WHERE
THE BULK OF THE COLDEST AIR WILL GO AS WELL. IN ORDER TO REMOVE
THE RISK OF LARGE FORECAST ERRORS WE WILL TREND THE FORECAST TO A
BLEND DOMINATED BY THE ECMWF...THUS INCREASING OUR TEMPERATURE
FORECASTS QUITE A BIT FOR EARLY NEXT WEEK ACROSS MAINLY OUR
WESTERN ZONES. HOWEVER...WE WILL REMAIN LEARY OF A POTENTIAL
SWITCH IN THE ECMWF. CHANGES WILL ALSO BE REFLECTED BY LOWERING
POPS A BIT FOR EARLY NEXT WEEK. BT
&&
.AVIATION...
STRONG SOUTHWEST WINDS WILL CONTINUE AT LIVINGSTON THIS MORNING
WITH GUSTS OVER 50 KNOTS AT TIMES. THESE WINDS WILL DECREASE BY
18Z. AREAS OF LIGHT SNOW CAUSING MVFR TO IFR CONDITIONS WILL
CONTINUE FROM MILES CITY EASTWARD BEFORE IMPROVING BY 00Z. SOUTH
CENTRAL MONTANA FROM BILLINGS WEST WILL HAVE LOWERING CEILINGS AND
AREAS OF SNOW DEVELOPING AFTER 18Z TODAY. THESE CONDITIONS WILL
SPREAD INTO LIVINGSTON AND SHERIDAN THIS EVENING. MVFR TO LOCAL
LIFR CONDITIONS WILL BE POSSIBLE AS WELL AS MOUNTAIN OBSCURATIONS.
RICHMOND
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 040 021/032 020/042 030/047 020/029 017/020 902/015
7/W 95/S 00/B 03/W 30/B 13/S 32/J
LVM 041 027/036 028/043 033/044 017/030 012/024 001/020
5/W 62/S 01/N 03/W 31/B 23/S 22/J
HDN 039 017/030 014/035 024/046 014/027 011/020 906/013
7/S 95/S 00/B 03/W 31/B 23/S 32/J
MLS 014 005/019 006/028 020/041 012/023 008/011 912/007
9/S 54/S 10/B 04/W 41/B 24/S 21/B
4BQ 032 013/026 005/032 021/047 015/024 011/018 909/012
9/S 85/S 10/B 03/W 41/B 24/S 32/J
BHK 011 000/013 903/026 018/041 012/019 003/006 914/003
+/S 43/S 10/B 04/W 51/B 23/S 21/B
SHR 041 018/030 011/040 022/051 015/028 011/022 904/016
5/W 96/S 00/B 02/W 31/B 24/S 32/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT FROM 5 PM THIS AFTERNOON TO
NOON MST WEDNESDAY FOR ZONE 38.
WIND ADVISORY IN EFFECT UNTIL 5 PM MST THIS AFTERNOON FOR
ZONE 65.
WY...WINTER WEATHER ADVISORY IN EFFECT FROM 5 PM THIS AFTERNOON TO
NOON MST WEDNESDAY FOR ZONE 99.
WINTER WEATHER ADVISORY IN EFFECT FROM 3 PM THIS AFTERNOON TO
NOON MST WEDNESDAY FOR ZONE 98.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1159 AM CST TUE DEC 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 513 AM CST TUE DEC 31 2013
UPPER AIR DATA CONTINUES TO SHOW THE REGION UNDER THE INFLUENCE
OF NORTHWESTERLY FLOW...WITH LOW PRESSURE CONTINUING TO SPIN OVER
THE HUDSON BAY REGION AND THE MAIN ASSOCIATED TROUGH EXTENDING
SOUTH THROUGH THE MIDWEST TOWARD THE GULF COAST...WHILE HIGH
PRESSURE REMAINS ANCHORED OFF THE SRN COAST OF CA. BEEN A QUIET
NIGHT WITH NO NOTABLE DISTURBANCES MOVING THROUGH...AND OUTSIDE OF
A BIT OF CIRRUS SLIDING IN FROM THE NORTHWEST ASSOCIATED WITH AN
UPPER LEVEL STREAK TO THE N/NE OF THE CWA...SKIES ARE MOSTLY
CLEAR. AT THE SURFACE...HIGH PRESSURE CONTINUES TO GRADUALLY SLIDE
OFF TO THE EAST...BUT WINDS FOR MUCH OF THE CWA REMAIN ON THE
LIGHT AND VARIABLE SIDE. WITH TIME...WINDS WILL BECOME MORE
SOUTHERLY AS THE CWA COMES UNDER MORE INFLUENCE OF LOW PRESSURE TO
THE WEST.
LOOKING TO THE REST OF TODAY...THE FORECAST REMAINS A DRY
ONE...WITH A SWITCH IN WINDS EXPECTED AND ABOVE AVERAGE HIGHS FOR
MOST LOCATIONS. SOUTHERLY WINDS ARE EXPECTED TO REMAIN THROUGH
MOST OF THE MORNING HOURS...BUT AN FRONTAL BOUNDARY APPROACHING
FROM THE WEST WILL BRING A GRADUAL SWITCH TO THE WEST. THIS FRONT
WILL CONTINUE TO MAKE ITS WAY THROUGH THE CWA DURING THE AFTERNOON
HOURS...AND BY 00Z THIS EVENING...MODELS ARE IN PRETTY GOOD
AGREEMENT SHOWING THE FRONT IN THE VICINITY OF THE NEB/KS STATE
LINE...USHERING IN N/NERLY WINDS. MAIN UNCERTAINTY FOR TODAY LIES
WITH HIGH TEMPERATURES. THE RAP DIDNT DO TOO BAD YESTERDAY AND
HAVE TEMPS TODAY AGAIN TRENDED THAT WAY...WHICH IS WARMER THAN
OTHER MODELS/GUIDANCE...BUT THIS FRONT REALLY DOESNT HAVE A COOLER
AIR PUSH WITH IT...AND INCREASED MIXING AHEAD/ALONG THE FRONT
LOOKS TO BRING 40S/50S AGAIN TO MOST OF THE CWA. GOING WITH
STRAIGHT RAP/HRRR WOULD SUGGEST FORECAST HIGHS ARE NOT HIGH ENOUGH
FOR SOME...BUT AM CONCERNED ABOUT THE AMOUNT OF UPPER LEVEL CLOUD
COVER THAT LOOKS TO AFFECT THE CWA FOR AT LEAST THE FIRST HALF OF
THE DAY. TEMP/CLOUD TRENDS WILL BE THE MAIN THING FOR THE DAY
SHIFT TO MONITOR FOR TODAY.
AS WE GET INTO THIS EVENING/OVERNIGHT...PRECIPITATION CHANCES MAKE
A RETURN. ANOTHER UPPER LEVEL SHORTWAVE DISTURBANCE WILL STARTING
MAKING ITS WAY SOUTHEAST OUT OF THE NRN ROCKIES OVERNIGHT...BUT BY
12Z WEDNESDAY THE BULK IS STILL JUST OFF TO THE NW OF THE CWA.
EXPECTING DRY CONDITIONS THROUGH AT LEAST MIDNIGHT...IT MAY EVEN
BE A FEW HOURS BEYOND THAT BEFORE SNOW CHANCES BEGIN MOVING INTO
NRN PORTIONS OF THE CWA. THROUGH THE EARLY MORNING HOURS...KEPT
ANY POPS CONFINED TO LOCATIONS NORTH OF HIGHWAY 6...WITH 40-50
POPS ALONG/NORTH OF HIGHWAY 92. SOME ACCUMULATION WILL BE
POSSIBLE...POTENTIALLY NEAR A HALF INCH THOSE FAR NRN LOCATIONS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 513 AM CST TUE DEC 31 2013
THE BIGGEST CONCERN WILL BE DETERMINING TIMING OF SNOW FOR
WEDNESDAY.
WE BEGIN THE LONG TERM ON WEDNESDAY AS A LOW-AMPLITUDE SHORTWAVE
TROUGH MOVES IN WITHIN NORTHWEST FLOW AND BEGINS TO DEEPEN OVER
OUR AREA AND CONTINUE TO DO SO AS IT TRAVERSES EAST. THIS WILL BE
A QUICK HITTER...AND MODEL SOLUTIONS GENERALLY AGREE THAT THE AXIS
OF THIS WAVE IS TRENDING A SOONER DEPARTURE. THIS QUICK HIT MEANS
THAT SNOW AMOUNTS WILL NOT AMOUNT TO MUCH AND I HAVE KEPT TOTAL
SNOW ACCUMULATIONS LESS THAN 2 INCHES AS THE PREVIOUS FORECAST
DID...WITH THE HIGHER AMOUNTS NORTH/NORTHEAST. MODELS/ENSEMBLES
SUCH AS NAM...SREF...AND NMM WRF INDICATE THAT THERE COULD BE SOME
LINGERING FLURRIES IN THE EVENING. ENSEMBLES CONTINUE TO TREND
COLDER FOR HIGHS AND I HAVE LOWERED THEM FROM PREVIOUS
FORECASTS...STRUGGLING TO GET INTO THE TEENS TO LOWER 20S FOR THE
MOST PART. WITH THE QUICKER DEPARTURE OF THE WAVE...I BACKED OFF
WIND SPEEDS. MILDER WEATHER WILL TRY TO RETURN BY FRIDAY WITH A
QUICK MOVING RIDGE...BUT ANOTHER SHOT OF MUCH COLDER AIR IS ON ITS
WAY FOR THE WEEKEND...REINFORCED EVEN FURTHER BY A MUCH COLDER
ARCTIC AIR MASS. HIGHS ON MONDAY MAY NOT MAKE IT OUT OF THE SINGLE
DIGITS...AND WITH SUCH STRONG COLD AIR ADVECTION...WIND SPEEDS
SHOULD BE STRONGER. THIS COULD SET US UP FOR WIND CHILLS LOW
ENOUGH TO MENTION IN THE HWO FOR MONDAY. WITH THE REINFORCING SHOT
OF VERY COLD AIR WILL LIKELY COME SOME STRATUS AND PERHAPS SOME
LIGHT SNOW. IT DOES NOT APPEAR THAT THIS WOULD BE A SCENARIO THAT
WOULD GIVE US SERIOUS SNOW ACCUMULATIONS.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z WEDNESDAY
AFTERNOON) ISSUED AT 1150 AM CST TUE DEC 31 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE AFTERNOON HOURS AS MOSTLY
CLEAR SKIES ARE EVIDENT IN SATELLITE IMAGERY UPSTREAM OF THE
TERMINAL. EXPECT THE ANTICIPATED COLD FRONT TO REACH THE TERMINAL
AROUND OR JUST BEFORE 01/00Z...WITH WINDS SHIFTING AND BECOMING
NORTHERLY AS A RESULT. OVERNIGHT...EXPECT CIGS TO EVENTUALLY LOWER
AND FOR MVFR CIGS TO DEVELOP...ALONG WITH SOME LIGHT SNOW...AFT
01/12Z. COULD ALSO SEE SOME MVFR VSBYS AFT 01/12Z...BUT KEPT OUT
OF THE TAF FOR THE TIME BEING UNTIL TIMING OF SNOW BANDS BECOMES
A BIT MORE CERTAIN.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ADO
LONG TERM...HEINLEIN
AVIATION...ROSSI
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
358 PM MST TUE DEC 31 2013
.UPDATE...
ISSUED AT 353 PM MST TUE DEC 31 2013
CALL TO AREA SPOTTERS SHOWED A BAND OF SLEET/FREEZING RAIN FROM
SOUTHEAST MT INTO WESTERN MEADE COUNTY...INCLUDING THE I-90
CORRIDOR FROM STURGIS TO SPEARFISH TO MOORCROFT. 21Z RAP SHOWED
NARROW BAND OF MIXED PRECIPITATION POTENTIAL FOR THESE AREAS
THROUGH ABOUT 04Z...WHEN EVERYTHING SHOULD SHIFT TO -SN. HAVE
INTRODUCED THESE ELEMENTS TO FORECAST AND ISSUED HEADLINES FOR THE
APPROPRIATE AREAS.
&&
.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 208 PM MST TUE DEC 31 2013
UPPER LEVEL ANALYSIS SHOWS NORTHWEST FLOW OVER THE
NORTHERN PLAINS. SURFACE MAP HAS AN ARCTIC BOUNDARY STRETCHING FROM
MONTANA THROUGH THE CWA INTO NEBRASKA. WARMER TEMPS TO THE SOUTH OF
THE BOUNDARY ARE IN THE 30S...WITH TEMPS TO THE NORTH IN THE SINGLE
DIGITS. LOW STRATUS COVERS MUCH OF THE REGION...WITH RADAR
DISPLAYING SOME LIGHT SNOW SHOWERS. WINDS ARE LIGHT AND VARIABLE.
AS THE ARCTIC BOUNDARY SPREADS SOUTH TONIGHT AND A SHORTWAVE
APPROACHES FROM THE WEST...LIGHT SNOW WILL TRANSITION SOUTH WITH THE
BEST FRONTOGENESIS. GENERALLY A COUPLE ADDITIONAL INCHES OR LESS OF
SNOW IS EXPECTED TONIGHT...WITH THE GREATER AMOUNTS OVER PARTS OF
NORTHEAST WYOMING AND THE NORTHERN BLACK HILLS. LOWS WILL RANGE FROM
AROUND 5 BELOW ZERO ACROSS CENTRAL SD TO ABOUT 20 ABOVE ZERO FARTHER
WEST.
SURFACE HIGH PRESSURE WILL SLIDE ACROSS ND ON NEW YEAR`S DAY...AND THE
PRESSURE GRADIENT WILL TIGHTEN A LITTLE...CAUSING BREEZY NORTHWEST
WINDS ACROSS NORTHWEST SD. LIGHT SNOW WILL CONTINUE THROUGH MUCH OF
THE DAY...WITH MINIMAL ACCUMULATIONS MOST PLACES. THE FROUDE NUMBER
AROUND 1.5 INDICATES THE POSSIBILITY FOR UPSLOPE-ENHANCED SNOW OVER
THE NORTHERN HILLS...ACCUMULATING ANOTHER INCH OR TWO THERE. HIGHS
WILL RANGE FROM THE TEENS ACROSS CENTRAL SD TO THE LOWER 30S IN
SOUTHWEST SD AND NORTHEAST WY.
SNOW WILL DIMINISH AND SKIES WILL BEGIN TO CLEAR WEDNESDAY NIGHT.
LOWS WILL BE AROUND 10 BELOW TO 15 ABOVE ZERO.
&&
.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 208 PM MST TUE DEC 31 2013
POWERFUL NORTHERN STREAM WILL CONTINUE TO DOMINATE THE
WEATHER IN THE PERIOD. MEAN CENTRAL CANADIAN POLAR VORTEX
WILL DRIVE ANOTHER SURGE OF ARCTIC AIR INTO THE REGION BY
SUNDAY...AS A LONG WAVE TROUGH ADVECTS ACROSS THE NW CONUS AND
PHASES WITH A PORTION OF THE POLAR LOW. PROGRESSIVE FLOW OVER THE
WESTERN ATLANTIC WILL SUPPORT ONLY A BRIEF STAY OF ARCTIC AIR
LOCALLY AS SEMI-ZONAL FLOW DEVELOPS ONCE AGAIN EARLY NEXT WEEK. MEAN
MODEL SOLUTIONS ARE SUGGESTING A POTENTIAL PATTERN CHANGE BY THE
MIDDLE OF NEXT WEEK WITH BREAKDOWN OF THE EASTERN PAC UPPER
RIDGE...ALLOWING A RETURN TO PROGRESSIVE FLOW OVER MUCH OF
NOAM...WITH THE POTENTIAL FOR A WARMER PATTERN AFTERWARD.
THUR-FRI...DEEP LAYER RIDGING AHEAD OF THE ADVECTING UPPER TROUGH
WILL SUPPORT STAUNCH WAA WITH WESTERLY FLOW SPREADING OVER THE
REGION. HAVE ADJUSTED TEMPS BOTH DAYS...WITH MILD CONDITIONS
EXPECTED OVER NE WY AND BH THUR...ALL PLACES FRIDAY AS FLOW
INCREASES AND MIXING SPREADS ACROSS THE SD PLAINS. 40S WILL BE
COMMON FRI...WITH 50S EXPECTED IN THE LEE OF THE BLACK
HILLS...INCLUDING RAPID CITY. THE RIDGE WILL SHIFT EAST FRIDAY
AFTERNOON...WITH A STRONG UPPER IMPULSE EXPECTED INTO THE
REGION...BRINGING INCREASING CHANCES FOR PRECIP...RAIN POSSIBLY AT
FIRST THEN TRANSITIONING TO SNOW FRIDAY EVENING. CONTINUED POP
MENTION IN THE PERIOD...OPTING FOR A MORNING MENTION OVER WY. ARCTIC
FRONT AND ASSOCIATED IMPULSE WILL ARRIVE SUN...WITH A CONTINUED POP
MENTION THEN. ALTHOUGH MOISTURE WILL BE SIGNIFICANTLY LACKING WITH
THIS SYSTEM...BEST CHANCES FOR ANY SNOW ACCUMS WILL BE OVER NE WY
AND THE NORTHERN BH. ARCTIC AIR WILL SURGE SOUTH ACROSS THE REGION
SUNDAY INTO MONDAY WITH VERY COLD TEMPS EXPECTED. MADE A SLIGHT DOWN
ADJUSTMENT TO TEMPS GIVEN BETTER MODEL AGREEMENT...ALTHOUGH CONCERNS
LINGER ON THE DEGREE OF CAA. WAA LOOKS TO ENSUE AS EARLY AS MON
AFTERNOON PER THE ECMWF...WITH A SLOW WARMUP ON TRACK THROUGH THE
MIDDLE OF NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 353 PM MST TUE DEC 31 2013
PRECIPITATION WILL OVERSPREAD THE AREA TONIGHT LEADING TO IFR
CIGS/VSBYS IN -SN...LIFR CONDITIONS LIKELY IN THE STRONGEST AREAS
OF -SN AND BLACK HILLS AREA. -FZRA/PL POSSIBLE THIS EVENING FROM
NORTHEAST WY INTO WEST CENTRAL SD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 5 AM MST WEDNESDAY FOR SDZ012-024-
025-072.
WY...WINTER WEATHER ADVISORY UNTIL 5 AM MST WEDNESDAY FOR WYZ056-057-
071.
&&
$$
UPDATE...HELGESON
SHORT TERM...POJORLIE
LONG TERM...JC
AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
352 PM CST TUE DEC 31 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 339 PM CST TUE DEC 31 2013
SNOW ASSOCIATED WITH TODAYS WAVE IS EXITING THE AREA...WITH JUST
SOME ISOLATED TO SCATTERED FLURRIES LINGERING. ANOTHER WAVE WILL RIDE
SOUTHEAST ALONG THE THERMAL GRADIENT TONIGHT. MODELS HAVE HAD GREAT
DIFFICULTY PINPOINTING WHERE THE BEST SNOW POTENTIAL WILL BE WITH
THIS WAVE...AND HOW MUCH QPF WILL FALL. THUS NEEDLESS TO SAY A LOW
CONFIDENCE FORECAST. BEST LARGE SCALE FORCING FROM THE WAVE SEEMS TO
GO TO OUR SOUTH. HOWEVER THE MID LEVEL FRONTAL BOUNDARY SHOULD BE
FURTHER NORTH...IN THE VICINITY OF THE MISSOURI RIVER VALLEY. LATEST
MODELS ARE TRENDING THE AREA OF SNOW FURTHER NORTH...CLOSER TO THE
REGION WHERE ISENTROPIC LIFT OVER THE MID LEVEL FRONT INTERACTS WITH
SOME OF THE LARGE SCALE FORCING. MODELS ALSO SHOWING SOME WEAK
INSTABILITY ABOVE THE FRONT...SUGGESTING WE COULD SEE SOME ENHANCED
BANDING. THE THERMAL PROFILE DOES FEATURE A DECENT SIZED AREA IN THE
DENDRITIC SNOW GROWTH ZONE...SUGGESTING RATIOS COULD END UP AROUND
15 TO 1. A CONSENSUS OF MODEL QPF VALUES SUGGEST 1 TO 2 INCHES IN
THE SNOW BAND...WITH ISOLATED AMOUNTS UP TO 3 INCHES IF RATIOS END
UP A BIT HIGHER. HOWEVER THE RUC...HRRR AND 18Z NAM ARE ALL MUCH
MORE AGGRESSIVE WITH QPF VALUES. THESE THREE WOULD SUGGEST A BAND OF
3 TO 5 INCHES. GIVEN THE LARGE SCALE FORCING...POTENTIAL BANDING AND
MODELS TRENDING UPWARD IN QPF...THIS CAN NOT BE COMPLETELY RULED
OUT. HOWEVER DO NOT WANT TO JUMP ON THIS AT THIS POINT GIVEN THE
REST OF THE GUIDANCE SUGGESTING LOWER AND THE MODEL INCONSISTENCY
FROM RUN TO RUN. THUS...TRENDED AMOUNTS UP...BUT ONLY TOWARDS MODEL
CONSENSUS...WHICH AT THIS TIME STILL SEEMS LIKE THE MORE LIKELY
SOLUTION.
THE NEXT QUESTION IS EXACTLY WHERE THIS BAND SETS UP. RIGHT
NOW ALMOST ALL GUIDANCE SUGGESTS THE MISSOURI RIVER VALLEY IS THE
MOST LIKELY LOCATION...WITH DECREASING AMOUNTS AS YOU GET TOWARDS
INTERSTATE 90. HOWEVER THE GEM AND HRRR ARE FURTHER NORTH...PUTTING
THE HIGHER AMOUNTS CLOSER TO OR JUST SOUTH OF INTERSTATE 90. FOR
THIS FORECAST PACKAGE WILL GO WITH THE MORE LIKELY SOLUTION ALONG
THE MISSOURI RIVER...BUT GIVEN THE RECENT NORTHWARD TRENDS CAN NOT
COMPLETELY RULE OUT THE HRRR AND GEM SOLUTION. SO FOR NOW...WILL
STICK WITH THE 1 TO 3 INCHES ALONG THE MISSOURI RIVER...DECREASING
TO AROUND AN INCH IN SIOUX FALLS AND LESS TO THE NORTH...BUT AS
MENTIONED ABOVE...EVENING SHIFT WILL NEED TO MONITOR TRENDS AND SEE
IF ADJUSTMENTS ARE NEEDED. EXPECT SNOW TO START AROUND 10 PM IN OUR
WEST...APPROACH SIOUX FALLS AND SIOUX CITY CLOSER TO MIDNIGHT...AND
SPENCER TO STORM LAKE AROUND 2 AM.
IT WILL BE A COLD ONE TONIGHT AS WELL WITH LOWS IN THE SINGLE DIGITS
BELOW ZERO NORTH OF INTERSTATE 90 AND SINGLE DIGITS ABOVE TO THE
SOUTH. KEPT THE TREND OF STAYING ON THE WARMER SIDE OF GUIDANCE
THOUGH...GIVEN THE CLOUD COVER AND AT LEAST A WEAKLY MIXED BOUNDARY
LAYER. WIND CHILLS WILL BE AROUND THE 20 BELOW ZERO ADVISORY CRITERIA
IN OUR NORTH. HOWEVER DECIDED TO HOLD OFF ON ONE AT THIS TIME...AS
WINDS SHOULD DROP OFF AFTER SUNSET AND GENERALLY BE UNDER 10
MPH...AND IF WINDS STAY UP MORE...TEMPERATURES WILL PROBABLY STAY A
BIT WARMER THAN FORECAST. THUS FEEL LIKE WIND CHILLS WILL HOVER A
FEW DEGREES EITHER SIDE OF 20 BELOW...AND GIVEN OUR COLD WINTER THUS
FAR...WILL NOT ISSUE ANOTHER ADVISORY AT THIS TIME. SNOW SHOULD EXIT
THE AREA FROM NORTHWEST TO SOUTHEAST ON WEDNESDAY MORNING...GIVING
WAY TO A MOSTLY CLOUDY DAY WITH JUST SOME SCATTERED FLURRIES. HIGHS
WILL WILL ONLY BE IN THE SINGLE DIGITS ABOVE AND BELOW ZERO WITH
WIND CHILLS LIKELY STAYING BELOW ZERO THROUGH THE DAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 339 PM CST TUE DEC 31 2013
CONTINUED COLD WEATHER PATTERN LOCKED IN PLACE FOR THE MAJORITY OF
THE MID AND LONG RANGE FORECAST. PREDOMINATE NORTHWEST UPPER LEVEL
FLOW WILL USHER IN SEVERAL WAVES THROUGH THE PERIOD WHICH WILL
PROVIDE REINFORCING SHOTS OF ARCTIC AIR. THE FIRST BLAST OF COLD AIR
CONTINUES TO SPREAD ACROSS THE REGION WEDNESDAY NIGHT. LIGHT
NORTHERLY WINDS AND DECREASING CLOUDS WILL LEAD TO EXTREMELY COLD
LOWS IN THE TEENS BELOW ZERO ACROSS THE BULK OF THE FORECAST
AREA...WITH THE SINGLE DIGITS BELOW CLOSER TO THE MISSOURI RIVER.
WIND CHILLS WILL BE BRUTALLY COLD AROUND 20 TO 30 BELOW FOR A LARGE
AREA...BUT WINDS SHOULD REMAIN WELL BELOW THE 10 MPH THRESHOLD FOR A
WIND CHILL HEADLINE.
THURSDAY WILL AGAIN BE VERY COLD WITH LIGHT WINDS TURNING A LITTLE
MORE SOUTHERLY IN THE AFTERNOON AS SURFACE HIGH PRESSURE SLIPS OFF
TO OUR EAST. MOSTLY CLEAR SKIES IN THE MORNING WILL SEE AN INCREASE
IN CLOUD COVER FROM THE WEST LATER IN THE DAY AHEAD OF THE NEXT
INCOMING SHORTWAVE. TEMPERATURES WILL NOT WARM MUCH...WITH MANY
LOCATIONS ONLY REACHING HIGHS AROUND ZERO. RETURN FLOW INCREASES
THURSDAY NIGHT AND FRIDAY...LEADING INTO THE ONLY MILD DAY OF THE
PERIOD. AFTER A SLIGHT DIP IN TEMPERATURES THURSDAY EVENING...
TEMPERATURES SHOULD BEGIN RISING OVERNIGHT WHILE CLOUDS INCREASE.
SOUTHERLY WINDS BECOME BREEZY ON FRIDAY...ESPECIALLY ACROSS OUR
EASTERN HALF...HOWEVER HIGHS ARE EXPECTED TO IMPROVE SOME 20 DEGREES
OR MORE FROM THURSDAY HIGHS. BLOWING AND DRIFTING OF THE RECENT
SNOWFALL COULD BE A CONCERN AS THE WINDS INCREASE ON FRIDAY.
STRONG COLD FRONT DIVES ACROSS THE REGION ON FRIDAY NIGHT...BRINGING
THE NEXT CHANCE OF SOME LIGHT SNOW ALONG AND BEHIND THE FRONT. UPPER
LEVEL TROUGH SINKS SOUTH OF THE FORECAST AREA LATE SATURDAY
NIGHT...USHERING IN ANOTHER ARCTIC BLAST FOLLOWED BY A REINFORCING
SHOT OF COLD AIR LATE SUNDAY AND SUNDAY NIGHT. LOW TEMPERATURES WILL
BE BACK INTO THE TEENS BELOW ZERO SUNDAY NIGHT AND MONDAY
NIGHT...WITH HIGHS EXPECTED TO BE BELOW ZERO FOR THE MAJORITY OF THE
FORECAST AREA. NORTHWEST WINDS ARE EXPECTED TO BE BREEZY SUNDAY
NIGHT INTO MONDAY WHICH PLACES NEARLY THE ENTIRE FORECAST AREA
SQUARELY INTO WIND CHILL WARNING TERRITORY AND AS COLD AS 35 TO 45
BELOW ZERO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1138 AM CST TUE DEC 31 2013
AREA OF LIGHT TO MODERATE SNOW WILL CONTINUE TO PUSH EAST ACROSS THE
AREA EARLY THIS AFTERNOON. VISIBILITY REDUCTIONS TO IFR ARE COMMON IN
THIS SNOW...MAINLY NORTH OF INTERSTATE 90. EXPECT THE SNOW TO COME TO
AN END FROM WEST TO EAST THROUGH THE AFTERNOON HOURS. A SECOND WAVE
SLIDING SOUTHEAST SHOULD BRING ANOTHER ROUND OF MAINLY LIGHT SNOW TO
THE AREA LATER TONIGHT INTO EARLY WEDNESDAY. LOOKS LIKE WE COULD SEE
VISIBILITY BACK INTO THE MVFR RANGE AFTER MIDNIGHT OVER A GOOD
PORTION OF THE AREA. THE STEADIEST SNOW IS CURRENTLY EXPECTED TO BE
SOUTH OF INTERSTATE 90...WHERE PERIODS OF IFR VISIBILITY ARE
POSSIBLE...THUS INTRODUCED A TEMPO INTO THE SUX TAF. CONFIDENCE OF
DROOPING BELOW 3SM IS LESS FURTHER NORTH...AND THUS KEPT THE FSD AND
HON TAF MVFR. SNOW SHOULD END FROM NORTHWEST TO SOUTHEAST THROUGH THE
EARLY MORNING. CIGS ARE TOUGH TO DETERMINE IN THESE ARCTIC AIR
MASSES. BASED ON WHAT IS OUT THERE NOW...DECIDED TO KEEP THE STRATUS
IN THE VFR RANGE WHEN IT IS NOT SNOWING...BUT THESE CLOUDS COULD END
UP LOWER BASED...SO SOMETHING TO KEEP AN EYE ON.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHENARD
LONG TERM...
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SPOKANE WA
901 AM PST Tue Dec 31 2013
.SYNOPSIS...
Weak storm systems will transit the region through this evening bringing
a mixed bag of light wintry precipitation. A stronger storm system
will pass through Thursday night bringing mainly rain in the
valleys and snow in the mountains. A cooler and drier pattern is
expected through the weekend.
&&
.DISCUSSION...
Minor morning updates to the forecast primarily include expanding
the intensity/mention of fog in the Basin/Moses Lake vicinity
today, otherwise no other significant change was made as long-wave
ridge axis positioning is off the coast and keeps a weak northwest
to southeast path over Eastern Washington and Northern Idaho for
disturbances to pass through with the most recent HRRR model runs
hinting of such a weak disturbance doing just that, so pops remain
in moderate shape form along with generally light QPF/snow
amount assigned. /Pelatti
&&
.AVIATION...
18Z TAFS: Weak weather disturbance dropping down in a northwest to
southeast trajectory allows the minor mention of precipitation,
including rain,snow, or even freezing rain given the persistent
inversion keeping a warm layer of air aloft which would support
melting of precipitation as it falls through it. Otherwise low
level clouds and fog remain and may stubbornly do so for a good
portion of the TAF interval thus IFR/LIFR ceilings and
visibilities remain depicted primarily in the overnight and
morning hours. /Pelatti
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 37 26 36 28 38 31 / 20 10 10 20 30 60
Coeur d`Alene 37 29 38 30 40 31 / 30 20 10 20 30 80
Pullman 41 30 40 31 41 33 / 50 10 10 10 10 60
Lewiston 44 31 41 32 45 35 / 40 20 10 10 10 60
Colville 32 25 33 27 33 29 / 20 10 20 30 30 60
Sandpoint 36 28 36 29 37 30 / 40 20 20 30 30 80
Kellogg 37 31 37 31 37 31 / 70 40 20 20 30 90
Moses Lake 39 22 35 23 36 30 / 10 0 0 10 10 20
Wenatchee 41 26 36 27 37 30 / 10 0 0 10 20 20
Omak 34 22 32 23 33 26 / 10 0 10 10 20 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
Northern Cascades-Moses Lake Area-Northeast Mountains-
Okanogan Highlands-Okanogan Valley-Spokane Area-Upper
Columbia Basin-Waterville Plateau-Wenatchee Area.
&&
$$