Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/17/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
824 PM MST MON DEC 16 2013
.UPDATE...WINDS ON MOST OF THE PLAINS HAVE DECREASED ALTHOUGH
STILL EXPECT A FEW GUSTS TO AROUND 30 MPH TO PUSH OUT ONTO THE
NEARBY ADJACENT PLAINS OVERNIGHT. MOST OF THE STRONGER GUSTS WILL
REMAIN OVER THE FOOTHILLS AND HIGHER TERRAIN...BUT EVEN THERE
SPEEDS ARE WEAKER THAN THOSE SEEN LAST NIGHT WITH MOST GUSTS
AROUND 40 MPH. MAIN CHANGE THIS EVENING WAS TO WARM UP
TEMPERATURES IN/NEAR THE FRONT RANGE WITH DOWNSLOPE WARMING.
HOWEVER...WINDS WILL BE WEAKER THAN LAST NIGHT AND CALMER PERIODS
SHOULD LEAD TO TEMPERATURES A FEW DEGREES COOLER THAN LAST
NIGHT ESPECIALLY IN VALLEY LOCATIONS. LATEST MODELS SUGGEST
INVERSIONS OVERNIGHT WILL BE VERY SHALLOW SO EVEN WITH LESS
DOWNSLOPE COMPONENT TOMORROW HIGH TEMPERATURES WILL LIKELY REACH
OR EXCEED LEVELS SEEN TODAY IN MOST LOCATIONS. VALLEYS MIGHT BE A
COUPLE DEGREES COOLER. OTHERWISE NEARLY FULL SUNSHINE SHOULD
EFFECTIVELY BURN OFF ANY INVERSIONS.
&&
.AVIATION...WINDS WERE JUST BEGINNING TO TRANSITION TO A MORE
NORMAL DRAINAGE FLOW WHICH IS SLOWER THAN NORMAL DUE TO GRADIENT
AND WEAK MOUNTAIN WAVE IN PLACE. EXPECT MAINLY NORMAL
SOUTHWESTERLY FLOW AT KDEN AND KAPA THROUGH TUESDAY MORNING WITH
OCCASIONAL GUSTY WEST WINDS TO AROUND 25-30 KTS EXPECTED AT KBJC.
LIGHTER FLOW ALOFT ON TUESDAY SO NOT ENTIRELY SURE WEST WINDS
GUSTS OF 15-20 KTS WILL MAKE IT AS FAR EAST AS KDEN AND
KAPA...THEY COULD STAY MORE SOUTHERLY OR EVEN LIGHT/VARIABLE
THROUGH THE DAY.
&&
.PREV DISCUSSION... /ISSUED 339 PM MST MON DEC 16 2013/
SHORT TERM...MODERATE NORTHWEST FLOW ALOFT CURRENTLY OVER THE
REGION WITH MID LEVEL JET STREAK MOVING INTO WESTERN WYOMING.
COMBINATION OF MIXING AND WEAK MOUNTAIN WAVE KEEPING GUSTY WINDS
GOING ACROSS HIGHER MOUNTAINS AND ALONG FOOTHILLS. ALSO A WEAK
INVERSION AT MOUNTAIN TOP...THOUGH IT SEEMS IT`S BEING OFFSET BY
SOME COLDER AIR AT MID LEVELS. THE MIXING HELPED SPREAD WINDS
FURTHER EAST ACROSS URBAN CORRIDOR. SOME GUSTS AROUND 55 MPH WERE
OBSERVED IN THE FAVORED TERRAIN. JET STREAK EXPECTED TO MOVE JUST
NORTHEAST OF THE AREA DURING THE EVENING...WITH INCREASED
SUBSIDENCE BY MIDNIGHT. CROSS SECTIONS SHOWING SOME MID LEVEL
WARMING BEHIND THE JET STREAK WHICH SHOULD INCREASE THE MOUNTAIN
TOP INVERSION AND ENHANCE THE MOUNTAIN WAVE. LATEST RAP CROSS
SECTIONS SHOW THE CROSS MOUNTAIN FLOW INCREASING TO AROUND 40 KTS
NEAR MOUNTAIN TOP AFTER MIDNIGHT. THUS...SHOULD SEE WINDS INCREASE
ACROSS THE MOUNTAINS AND FOOTHILLS OVERNIGHT. LATEST MODEL
GUIDANCE STILL INDICATING THE STRONGER WINDS IN THE MID AND UPPER
SLOPES OF THE NORTHERN FOOTHILLS...AND SEEMS REASONABLE BASED ON
THE NORTHWEST FLOW ALOFT. SPEEDS TO STAY BELOW HIGH WIND CRITERIA.
POTENTIAL FOR OCCASIONAL WESTERLY WINDS SPREADING ONTO THE
ADJACENT PLAINS. DID INCREASE THE WINDS SLIGHTLY ALONG THE BASE OF
THE FOOTHILLS OVERNIGHT. INCREASED OVERNIGHT TEMPERATURES A FEW
MORE DEGREES...ESPECIALLY IN AND NEAR FOOTHILLS WHERE DOWNSLOPE
WINDS WILL KEEP TEMPERATURES FAIRLY MILD. ON TUESDAY...FLOW ALOFT
BECOMES A BIT MORE WESTERLY AND DECREASES SLIGHTLY. THERE IS SOME
WEAK DOWNWARD MOTION...WITH WEAKENING SUBSIDENCE. BUT MIXING IS
EXPECTED BY AFTERNOON WHICH WILL HELP KEEP SOME GUSTY WINDS GOING
IN AND NEAR FOOTHILLS. ACROSS PLAINS...WEAK SURFACE GRADIENT WILL
ALLOW FOR WINDS TO BE LIGHT AND TREND TOWARD DIURNAL TRENDS.
TEMPERATURES ACROSS PLAINS TO BE SLIGHTLY COOLER DUE TO LESS
DOWNSLOPE FLOW...STILL SHOULD WARM CLOSE TO 60 DEGREES.
LONG TERM...FLOW ALOFT WILL FLATTEN AND BECOME WESTERLY TUESDAY
NIGHT AND WEDNESDAY AS AN UPPER LEVEL TROUGH MOVES OVER THE PACIFIC
NORTHWEST AND KNOCKS DOWN THE RIDGE OVER THE WESTERN STATES. AIRMASS
WILL REMAIN WARM UNDER THE WESTERLY FLOW WITH HIGHS IN THE 60S.
MOISTURE AT THE UPPER LEVELS WILL INCREASE...SO EXPECT HIGH CLOUDS
TO INCREASE AND COULD HOLD BACK TEMPERATURES SOME IF THICK WAVE
CLOUDS FORM. RECORD HIGH FOR WEDNESDAY IS 66 AND COULD BE BROKEN IF
ENOUGH SUNSHINE PREVAILS.
A WEAK SHORT WAVE TROUGH WILL MOVE ACROSS THE STATE WEDNESDAY NIGHT
AS FLOW ALOFT BACKS TO THE SOUTHWEST. WILL HAVE LOW POPS IN THE
MOUNTAINS FOR THIS. ELSEWHERE JUST EXPECTED AN INCREASE IN CLOUDS.
TEMPERATURES WILL REMAIN MILD WEDNESDAY NIGHT WITH LOWS ABOVE
FREEZING MOST LOCATIONS.
COLD FRONT WILL MOVE ACROSS NORTHEAST COLORADO THURSDAY MORNING.
HIGHS WILL BE REACHED EARLY IN THE DAY AND EXPECT TEMPERATURES TO
FALL DURING THE AFTERNOON HOURS. THE COLD AIRMASS IS SHALLOW SO DO
NOT EXPECT MUCH IF ANY PRECIPITATION TO FORM DUE TO UPSLOPE
WINDS. MODELS SHOWING A BAND OF PRECIPITATION FORMING OVER
NORTHWEST COLORADO AND INTO WYOMING DUE TO THE JET. THE NORTH
CENTRAL MOUNTAINS WILL HAVE A GOOD CHANCE AT SEEING SOME OF THE
SNOW...BUT ELSEWHERE CHANCES ARE LOW. THE SNOW THAT DOES FALL IS
EXPECTED TO BE LIGHT.
MAIN LOW DIVES SOUTH AND CUTS OFF OVER NORTHERN MEXICO AND THE MAIN
JET STAYS TO OUR NORTH LEAVING THE AREA UNDER A WEAK FLOW ALOFT
FRIDAY AND SATURDAY. THERE WILL BE ANOTHER CHANCE/SLIGHT CHANCE OF
SNOW AS THE TROUGH AXIS MOVE ACROSS COLORADO SATURDAY. THOUGH IF ANY
SNOW FORMS IT WILL BE LIGHT. THE MOUNTAINS WILL HAVE THE BEST CHANCE
FOR SNOW DUE TO OROGRAPHIC LIFT. TEMPERATURES WILL BE COOL FRIDAY
AND SATURDAY WITH HIGHS IN THE 30S OVER NORTHEAST COLORADO.
NORTHWEST FLOW ALOFT WILL PREVAIL SUNDAY AND MONDAY AS THE MAIN
TROUGH SHIFTS EAST OF COLORADO AND A RIDGE DEVELOPS ALONG THE WEST
COAST. TEMPERATURES WILL WARM A LITTLE SUNDAY AND MONDAY. MAY BE
ENOUGH MOISTURE EMBEDDED IN THE NORTHWEST FLOW ALOFT TO PRODUCE
LIGHT SNOW AT TIMES ALONG AND WEST OF THE CONTINENTAL DIVIDE.
AVIATION...
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....MEIER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
946 PM EST MON DEC 16 2013
.SYNOPSIS...
A QUICK MOVING ALBERTA CLIPPER SYSTEM WILL PUSH THROUGH OVERNIGHT INTO
TUESDAY MORNING WHILE A WEAK COASTAL LOW PRESSURE FORMS AND THEN
MOVES OFF TO THE NORTHEAST ON TUESDAY. ANOTHER WEAK WAVE ALOFT
QUICKLY MOVES THROUGH LATE TUESDAY NIGHT INTO WEDNESDAY MORNING
WHILE HIGH PRESSURE NOSES BACK IN FROM THE WEST. A RATHER DRAMATIC
WARMUP IS EXPECTED FOR THE END OF THE WEEK WHILE A FRONTAL
BOUNDARY FROM THE NORTHWEST IS EXPECTED TO ARRIVE ON FRIDAY NIGHT.
THE MAY REMAIN IN OR NEAR OUR REGION FOR MUCH OF THE WEEKEND NEVER
FULLY MOVING THROUGH UNTIL EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
HIGH PRESSURE WILL BE MOVING EAST OF THE AREA BY SUNRISE. MID
CLOUDS HAVE BEEN RAPIDLY OVERSPREADING THE REGION IN ADVANCE OF
THE NEXT SYSTEM AND THAT WILL CONTINUE.
EXCELLENT RADIATIONAL COOLING CONDITIONS SET UP AFTER SUNSET IN
OUR NORTHERN ZONES BEFORE ANY CLOUDS COULD APPROACH, AND
TEMPERATURES WERE MODIFIED SIGNIFICANTLY COLDER IN THOSE AREAS.
TEMPERATURES WILL HOLD STEADY OR RISE ONCE THE CLOUDS MOVE IN UP
NORTH. WINDS WILL REMAIN LIGHT FOR THE REMAINDER OF THE NIGHT.
AN APPROACHING LOW/FRONT WILL BRING LIGHT SNOW TO THE AREA. BASED
ON THE LATEST HRRR GUIDANCE, SLOWED DOWN THE ARRIVAL BY A COUPLE
HOURS. QUICKLY RAMPED THE POPS UP AFTER 06Z...AND THEY REACH
CATEGORICAL/LIKELY IN MOST AREAS BEFORE 12Z.
DID NOT CHANGE SNOWFALL/QPF AMOUNTS FROM PREVIOUS FORECAST FOR THE
NEAR TERM PERIOD. A WINTER WEATHER ADVISORY CONTINUES, NO CHANGES
WERE MADE TO SNOW AMOUNTS OR COVERAGE. LIGHT ACCUMULATING SNOWS WILL
IMPACT THE MORNING RUSH HOUR...SO TAKE THIS INTO ACCOUNT WHEN
PLANNING ACTIVITIES FOR TUESDAY.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
THE FAST MOVING LOW PRESSURE SYSTEM WILL CONTINUE TO MOVE THROUGH
THE REGION TUE MORNING. IT WILL HAVE MOST OF ITS IMPACTS ACROSS THE
AREA DURING THE MORNING. THE CATEGORICAL/LIKELY POPS ACROSS THE N
AND ERN AREAS AT 18Z WILL DIMINISH THROUGH THE AFTERNOON. ADDITIONAL
ACCUMS WILL OCCUR IN THE MORNING BRINGING THE TOTAL ACCUMS IN THE
2-4 INCH RANGE ACROSS NRN AREAS...1-2 INCHES ALONG THE I-95
CORRIDOR...AND LESS THAN AN INCH ELSEWHERE. RAIN WILL MIX WITH THE
SNOW ACROSS SRN NJ AND NRN DELAWARE BEFORE ENDING. HIGH TEMPERATURES
WILL RANGE FROM THE LOW/MID 40S OVER THE DELMARVA (MAYBE EVEN A FEW
UPPER 40S)...TO THE MID/UPPER 20S OVER THE SRN POCONOS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
A RATHER POTENT SHORTWAVE WILL PUSH THROUGH LATE TUESDAY NIGHT
ACROSS PORTIONS OF OUR DELMARVA ZONES. MODELS ARE SHOWING A DECENT
AMOUNT OF QPF WITH THIS FEATURE AS THE TROUGH AXIS BECOMES SLIGHTLY
NEGATIVE AND ENTERS INTO A REGION THAT HAS BEEN EXPERIENCING DEEP
LAYER SOUTHWEST FLOW...PLENTY OF MOISTURE ALOFT TO MAKE SNOW. THE
SETUP LOOKS PRETTY GOOD FOR A QUICK MOVING SQUALL TO FORM AND PUSH
THROUGH PORTIONS OF CENTRAL DELMARVA HEADING INTO SOUTHERN NEW
JERSEY THROUGH EARLY WEDNESDAY MORNING...GREATLY REDUCING
VISIBILITIES. TOTAL TOTALS JUMP INTO THE MID-50S ACROSS OUR SOUTHERN
ZONES SO A CONVECTIVE-LIKE/BANDING OF SNOW CAN NOT BE RULED
OUT...SNOW AMOUNTS WERE INCREASED FROM EARLIER THIS MORNING.
BOUNDARY LAYER TEMPERATURES WILL BE THE LIMITING FACTOR AT THE ONSET
AS THEY WILL BE IN THE LOW-30S AND TAKE A FEW HOURS OF PRECIP
LOADING TO DROP BELOW FREEZING TO HAVE BETTER ACCUMULATION CHANCES.
RATIOS SHOULD BE INCREASING THROUGH THE NIGHT AS LAPSE RATES
INCREASE WITH THE MID-LEVEL COLD POOL MOVING IN ALOFT AND SLIGHTLY
DRIER AIR PUSHES IN FROM THE WEST-NORTHWEST.
WEAK RIDGING THEN MOVES IN BEHIND THE DEPARTING SHORTWAVE AS THE
MID-LEVEL FLOW BECOMES MORE ZONAL. THE WEAK RIDGING PASSING OFFSHORE
BY FRIDAY AS A SHARPER TROUGH FORMS OUT IN THE WEST. THIS GENERATES
A MORE ROBUST DEEP-LAYER SOUTHWESTERLY FLOW ALOFT COMBINED WITH A
SUB-TROPICAL RIDGE SITTING OFF THE SOUTHEAST COAST. IT MIGHT COME AS
A SHOCK TO MOST BUT WE ARE EXPECTING TEMPERATURES THE LATER HALF OF
THE WEEK, INTO THE WEEKEND, TO DRAMATICALLY INCREASE UNDER THE
STRENGTHENING RETURN FLOW. DID NOT GO CRAZY WITH RAISING
TEMPERATURES TOO MUCH AT THIS POINT, AS ONE QUICK MOVING COLD FRONT
COULD SPOIL THE WARM-UP, BUT DID INCREASE TEMPERATURES THROUGH THE
WEEKEND...POSSIBLY NEARING THE LOW-60S BY SUNDAY.
THIS IS ALL DEPENDENT UPON THE PROGRESSION OF A COLD FRONT NEARING
FROM THE NORTHWEST LATE FRIDAY. THE PAST TWO MODEL RUNS SHOW THE
FRONT GETTING STRETCHED OUT AND BECOMING PARALLEL TO THE FLOW ALOFT
ULTIMATELY SLOWING ITS FORWARD PROGRESS. IT MAY PASS THROUGH A
PORTION OF OUR REGION BEFORE STALLING AND THEN LIFTING BACK NORTH AS
A WARM FRONT LATE IN THE WEEKEND.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
HIGH PRESSURE WILL MOVE EAST OF THE AREA OVERNIGHT. LOW PRESSURE
WILL ADVANCE FROM THE OHIO VALLEY AND BRING CLOUDS/PRECIP TUESDAY
MORNING WHICH WILL PERSIST THROUGH THE END OF THE TAF PERIOD.
TONIGHT...MID CLOUDS HAVE MOVED IN AND WINDS HAVE DROPPED OFF TO
UNDER 5 KNOTS. AS THE HIGH MOVES AWAY...SFC WINDS WILL BECOME
ERLY OVER THE AREA AFTER MIDNIGHT. WINDS SPEEDS WILL REMAIN MOSTLY
5 KTS OR LESS. CLOUDS WILL THICKEN OVERNIGHT AND LIGHT SNOW WILL
OVERSPREAD THE AREA FROM THE WEST BY DAWN. ONLY LIGHT ACCUMS ARE
EXPECTED BY 12Z.
TUESDAY...CIGS AND VSBYS WILL BECOME SHARPLY LOWER ONCE THE SNOW
OVERSPREADS THE AREA. A PERIOD OF IFR CONDITIONS ARE EXPECTED DURING
THE MORNING. WARMER AIR WILL BEGIN TO ARRIVE FROM THE S/SE LATER IN
THE MORNING...SO KMIV/KACY/KILG/KPHL WILL PROBABLY HAVE SOME MIX
WITH RAIN DURING THE MORNING. WINDS WILL BECOME SRLY ACROSS THE SRN
TAF SITES BY LATE MORNING...THEN TURN SW ONCE THE LOW PULLS AWAY.
MUCH OF THE STEADY PRECIP WILL ND FROM W TO E DURING THE AFTERNOON.
OUTLOOK...
TUESDAY NIGHT - WEDNESDAY MORNING...MVFR/IFR POSSIBLE IN A QUICK
MOVING SNOW SQUALL, MOSTLY SOUTH OF PHL. SNOW SHOWERS POSSIBLE
FURTHER NORTH. CONFIDENCE IS MEDIUM.
WEDNESDAY - THURSDAY...VFR WITH GUSTY WEST WINDS.
THURSDAY NIGHT - SATURDAY...MVFR SHOWERS POSSIBLE STARTING LATE
THURSDAY NIGHT. WINDS TURN MORE SOUTHWESTERLY.
&&
.MARINE...
SCA FLAGS WERE TAKEN DOWN WITH THE 330 PM CWF. NO SIGNIFICANT
CHANGES TO THE FORECAST WERE MADE ON THE 930 PM UPDATE. HIGH
PRESSURE WILL SETTLE ACROSS THE WATERS OVERNIGHT AND WINDS WILL BE
LIGHT. WIND DIRECTIONS WILL BE MOSTLY N/NW EARLY...THEN SWING
AROUND TO E/SE BY DAWN. SEAS WILL DIMINISH BACK DOWN TO 2 FT BY
DAWN.
LOW PRESSURE WILL MOVE NORTH OF THE WATERS TUE. WIND SPEEDS WILL
INCREASE DURING THE MORNING FROM THE SE...THEN AS THE LOW MOVES BY
WIND DIRECTIONS WILL BECOME MORE SW/W BY LATE AFTERNOON. IT APPEARS
THAT WIND SPEEDS WILL REMAIN SHORT OF SCA CRITERIA AND SEAS ON THE
OCEAN WILL INCREASE BACK TO 3 OR 4 FT...SO WE WILL HOLD THE SCA FLAG
AT THIS TIME.
OUTLOOK...
TUESDAY NIGHT - FRIDAY...SCA CONDITIONS ARE POSSIBLE FOR A MAJORITY
OF THE TIME AS A STRENGTHENING SOUTHWEST SURFACE FLOW DEVELOPS WITH
HIGH PRESSURE TO OUR SOUTHEAST.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY FROM 5 AM TO 3 PM EST TUESDAY FOR
PAZ054-055-060>062-101-103-105.
WINTER WEATHER ADVISORY FROM 6 AM TO 4 PM EST TUESDAY FOR
PAZ070-071-102-104-106.
NJ...WINTER WEATHER ADVISORY FROM 5 AM TO 3 PM EST TUESDAY FOR
NJZ001-007>009.
WINTER WEATHER ADVISORY FROM 6 AM TO 4 PM EST TUESDAY FOR
NJZ010-012>015-018>020-027.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...HEAVENER
NEAR TERM...SZATKOWSKI/O`HARA
SHORT TERM...SZATKOWSKI/O`HARA
LONG TERM...HEAVENER
AVIATION...SZATKOWSKI/HEAVENER/O`HARA
MARINE...SZATKOWSKI/HEAVENER/O`HARA
AREA FORECAST DISCUSSION
NWS MIAMI FL
1254 PM EST SUN DEC 15 2013
.AVIATION...
MAINLY VFR CONDITIONS WILL PREVAIL THIS AFTERNOON AND EVENING
ESPECIALLY AHEAD OF THE FRONT. THE MAIN LINE OF SHOWERS ASSOCIATED
WITH THE FRONT WILL REACH PBI FIRST AND THEN MOVE SOUTHWARD.
HOWEVER, A FEW SHOWERS COULD ALSO DEVELOP AHEAD OF THE FRONT NEAR
THE EAST COAST TERMINALS THIS AFTERNOON AND EVENING. WE BELIEVE
THAT MINIMUM THUNDER ACTIVITY WILL BE OBSERVED WITH THIS FRONT DUE
TO ABUNDANT MID LEVEL DRY AIR AND WEAK FORCING. THE STRONGEST
SHOWERS COULD SEE BRIEF MVFR CONDITIONS THIS AFTERNOON AND
EVENING. THE ATMOSPHERE IS FORECAST TO BE MORE MOIST BEHIND THE
FRONT. THIS COULD LEAD TO BKN MVFR CEILINGS IN SOME SPOTS BEFORE
O0Z TUESDAY.
&&
.PREV DISCUSSION... /ISSUED 1150 AM EST SUN DEC 15 2013/
UPDATE...
THE SHOWERS CONTINUE TO HAVE DIFFICULTY MAKING IT INTO THE EASTERN
PORTION OF THE CWA. MODEL SOUNDINGS ARE SHOWING DRY MID LEVELS,
WHICH MAY BE HAMPERING THEIR PROGRESSION. SO, HAVE ADJUSTED POPS
ACCORDINGLY FOR THE NEXT COUPLE OF HOURS TO ACCOUNT FOR THIS.
FOR THIS AFTERNOON, NEW HRRR RUN SHOWS THE LINE NOW FALLING APART
THIS AFTERNOON BEFORE IT MAKES IT INTO THE FT LAUDERDALE METRO
AREA. THIS IS A POSSIBLE SCENARIO, GIVEN THE CLOUD COVER NOW IN
PLACE OVER ALL OF SOUTH FLORIDA AND THE DIFFICULTIES MENTIONED
ABOVE. HOWEVER, GIVEN THERE WAS ONLY CHANCE POPS IN ANYWAYS, HAVE
OPTED TO LET THEM RIDE FOR NOW.
PREV DISCUSSION... /ISSUED 930 AM EST SUN DEC 15 2013/
UPDATE...
SHOWERS AND A COUPLE OF THUNDERSTORMS ARE MOVING INTO THE
NORTHWESTERN PORTION OF SOUTH FLORIDA THIS MORNING. HAVE BOOSTED
POPS TO REFLECT THIS AND TRANSLATED THE LINE TO THE SOUTH EAST.
THIS IS A PRE-FRONTAL TROUGH, AHEAD OF THE APPROACHING COLD FRONT,
WHICH IS CURRENTLY OVER CENTRAL FLORIDA. THE SHOWERS DO APPEAR AS
THOUGH THEY ARE HAVING TROUBLE KEEPING TOGETHER ACROSS THE
MAINLAND, AND ALMOST FALLING APART ON THE EAST COAST. HOWEVER,
GIVEN DAYTIME HEATING WILL HELP INSTABILITY, HAVE BUMPED UP POPS
FURTHER SOUTH AS WELL. THE QUESTION IS, THIS AFTERNOON, AND IF
THE LINE WILL HOLD TOGETHER ENOUGH TO CONTINUE SHOWERS AND
THUNDERSTORMS.
AS FAR A THUNDERSTORMS ACROSS THE AREA, THIS MORNINGS SOUNDING
DOES SHOW ALMOST 3000 JOULES OF CAPE OVER MIAMI. HOWEVER, THIS
HIGHER CAPE WILL BE PUSHED OUT OF THE AREA AS THE TROUGH CONTINUES
TO APPROACH. HOWEVER, THE FRONT DOES LOOK AS THOUGH IT MAY CATCH
UP TO THE LARGER LINE OF SHOWERS, HELPING TO PUSH IT THROUGH
QUICKER THAN IT CURRENTLY IS. THIS COULD HELP TO PROVIDE THE
TRIGGER FOR SOME ISOLATED STORMS THIS AFTERNOON.
THE HRRR DOES SHOW THE LINE WEAKENING AS IT APPROACHES THE MIAMI
METRO AREA, ALTHOUGH STILL SHOWS IT BRINGING A LINE OF SHOWERS
THROUGH. TIMING IS CURRENTLY INTO THE WEST PALM BEACH METRO AREA
AROUND 16Z, THE BROWARD METRO AREAS AROUND 18 OR 19Z, AND THE
MIAMI METRO AREA BETWEEN 19 AND 20Z. OF COURSE GIVE OR TAKE SOME A
LITTLE TIME, SO HAVE CHANCE POPS FROM 18Z THROUGH 00Z, ALTHOUGH
MOST LIKELY WILL HAVE TO ADJUST IN A FEW HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 62 74 58 75 / 30 20 10 10
FORT LAUDERDALE 66 75 63 77 / 30 20 10 10
MIAMI 67 75 62 77 / 20 20 20 10
NAPLES 58 72 51 76 / 20 - 10 -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...71/JE
AREA FORECAST DISCUSSION
NWS MIAMI FL
1150 AM EST SUN DEC 15 2013
.UPDATE...
THE SHOWERS CONTINUE TO HAVE DIFFICULTY MAKING IT INTO THE EASTERN
PORTION OF THE CWA. MODEL SOUNDINGS ARE SHOWING DRY MID LEVELS,
WHICH MAY BE HAMPERING THEIR PROGRESSION. SO, HAVE ADJUSTED POPS
ACCORDINGLY FOR THE NEXT COUPLE OF HOURS TO ACCOUNT FOR THIS.
FOR THIS AFTERNOON, NEW HRRR RUN SHOWS THE LINE NOW FALLING APART
THIS AFTERNOON BEFORE IT MAKES IT INTO THE FT LAUDERDALE METRO
AREA. THIS IS A POSSIBLE SCENARIO, GIVEN THE CLOUD COVER NOW IN
PLACE OVER ALL OF SOUTH FLORIDA AND THE DIFFICULTIES MENTIONED
ABOVE. HOWEVER, GIVEN THERE WAS ONLY CHANCE POPS IN ANYWAYS, HAVE
OPTED TO LET THEM RIDE FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 930 AM EST SUN DEC 15 2013/
UPDATE...
SHOWERS AND A COUPLE OF THUNDERSTORMS ARE MOVING INTO THE
NORTHWESTERN PORTION OF SOUTH FLORIDA THIS MORNING. HAVE BOOSTED
POPS TO REFLECT THIS AND TRANSLATED THE LINE TO THE SOUTH EAST.
THIS IS A PRE-FRONTAL TROUGH, AHEAD OF THE APPROACHING COLD FRONT,
WHICH IS CURRENTLY OVER CENTRAL FLORIDA. THE SHOWERS DO APPEAR AS
THOUGH THEY ARE HAVING TROUBLE KEEPING TOGETHER ACROSS THE
MAINLAND, AND ALMOST FALLING APART ON THE EAST COAST. HOWEVER,
GIVEN DAYTIME HEATING WILL HELP INSTABILITY, HAVE BUMPED UP POPS
FURTHER SOUTH AS WELL. THE QUESTION IS, THIS AFTERNOON, AND IF
THE LINE WILL HOLD TOGETHER ENOUGH TO CONTINUE SHOWERS AND
THUNDERSTORMS.
AS FAR A THUNDERSTORMS ACROSS THE AREA, THIS MORNINGS SOUNDING
DOES SHOW ALMOST 3000 JOULES OF CAPE OVER MIAMI. HOWEVER, THIS
HIGHER CAPE WILL BE PUSHED OUT OF THE AREA AS THE TROUGH CONTINUES
TO APPROACH. HOWEVER, THE FRONT DOES LOOK AS THOUGH IT MAY CATCH
UP TO THE LARGER LINE OF SHOWERS, HELPING TO PUSH IT THROUGH
QUICKER THAN IT CURRENTLY IS. THIS COULD HELP TO PROVIDE THE
TRIGGER FOR SOME ISOLATED STORMS THIS AFTERNOON.
THE HRRR DOES SHOW THE LINE WEAKENING AS IT APPROACHES THE MIAMI
METRO AREA, ALTHOUGH STILL SHOWS IT BRINGING A LINE OF SHOWERS
THROUGH. TIMING IS CURRENTLY INTO THE WEST PALM BEACH METRO AREA
AROUND 16Z, THE BROWARD METRO AREAS AROUND 18 OR 19Z, AND THE
MIAMI METRO AREA BETWEEN 19 AND 20Z. OF COURSE GIVE OR TAKE SOME A
LITTLE TIME, SO HAVE CHANCE POPS FROM 18Z THROUGH 00Z, ALTHOUGH
MOST LIKELY WILL HAVE TO ADJUST IN A FEW HOURS.
PREV DISCUSSION... /ISSUED 650 AM EST SUN DEC 15 2013/
AVIATION...
SOUTHWESTERLY WINDS ARE EXPECTED AT ALL TAF SITES TODAY. WITH THE
COLD FRONT MOVING SOUTHWARD ACROSS THE FLORIDA PENINSULA THERE IS
A CHANCE OF SHOWERS THIS AFTERNOON AND EVENING AT ALL TAF SITES.
THERE IS ALSO A SLIGHT CHANCE OF THUNDERSTORMS. THE CONFIDENCE OF
THUNDERSTORMS IS LOW SINCE IT IS NOT CLEAR WITH THE LACK OF STRONG
FORCING AND WEAK LAPSE RATES IF THE THUNDERSTORMS WILL SURVIVE AS
THEY CONTINUE TO MOVE SOUTHWARD OR MOVE FROM THE GULF TO THE LAND. FOR
NOW, INCLUDED VCSH FOR ALL TAF SITES AFTER 17Z. THE CEILING AND
VIS SHOULD MOSTLY STAY IN THE VFR CONDITIONS FOR THE DAYTIME HOURS
TODAY...BUT COULD FALL DOWN INTO THE MVFR CONDITIONS WITH ANY
PASSING SHOWERS.
PREV DISCUSSION... /ISSUED 244 AM EST SUN DEC 15 2013/
SHORT TERM (TODAY-TUESDAY)...
RECENTLY ANIMATED WATER VAPOR LOOP SHOWED A BROAD LONG WAVE TROUGH
PROGRESSING EASTWARD TOWARD THE EAST COAST AND PLENTY OF MID/UPPER
MOISTURE SPREADING ENE AHEAD OF IT ACROSS THE REGION. THE EARLY
MORNING SURFACE ANALYSIS SHOWED A COLD FRONT ASSOCIATED WITH THIS
UPPER FEATURE EXTENDING SOUTHWEST ACROSS THE FLORIDA PANHANDLE TO
THE CENTRAL GULF OF MEXICO WITH LIGHT TO MODERATE SOUTHERLY FLOW
ACROSS MUCH OF THE STATE. DEW POINTS ALONG AND AHEAD OF THIS BOUNDARY
RANGED FROM THE UPPER 60S ACROSS CENTRAL FLORIDA TO THE LOWER 70S
ACROSS THE SOUTHERN EXTENT OF THE PENINSULA. THE LATEST SHORT-RANGE
NUMERICAL GUIDANCE REMAINS IN GOOD AGREEMENT AND INDICATES THIS
FRONTAL BOUNDARY CONTINUING ESE THROUGH THE LOCAL AREA LATER THIS
EVENING THROUGH TONIGHT. RAIN CHANCES WILL STEADILY INCREASE ACROSS
THE AREA THROUGH THE DAY...MAINLY ALONG AND AHEAD OF THIS
APPROACHING BOUNDARY. DESPITE THE AMPLE MOISTURE IN PLACE ALONG WITH
THE APPROACHING BOUNDARY...LIMITED FORCING AND POOR LAPSE RATES WILL
LIMIT THUNDERSTORM PROBABILITIES TODAY ACROSS THE LOCAL AREA. FOR
NOW...WE WILL CONTINUE TO INCLUDE ISOLATED TSTMS IN THIS GRIDDED
PACKAGE AND UPDATE AS CONDITIONS EVOLVE TODAY. MODEL RAINFALL
ACCUMULATIONS THROUGH TONIGHT REMAIN LIGHT WITH VALUES RANGING FROM
A TENTH TO A HALF OF AN INCH ACROSS THE AREA. AS TYPICALLY
OBSERVED...LOCALIZED HIGHER AMOUNTS WILL REMAIN POSSIBLE IN ANY
HEAVIER ACTIVITY THAT DEVELOPS OR BECOMES CONCENTRATED.
MONDAY THROUGH TUESDAY...THE DEEP LAYER MOISTURE AXIS ASSOCIATED
WITH THE FRONTAL BOUNDARY EXTENDING SOUTHWEST ACROSS SRN FLORIDA
PENINSULA WILL KEEP A SLIGHT CHANCE OF SHOWERS IN THE FORECAST
THROUGH THE DAY MONDAY. MONDAY NIGHT THROUGH TUESDAY...DRIER AND
COOLER AIR WILL BEGIN TO OVERSPREAD THE LOCAL AREA IN THE WAKE OF
THE BOUNDARY AS HIGH PRESSURE BUILDS EASTWARD ALONG THE NORTHERN
GULF COAST STATES. THE SHORT-RANGE TEMPERATURE GUIDANCE INDICATES
OVERNIGHT LOWS RANGING FROM THE MID 40S ACROSS GLADES COUNTY TO THE
LOWER 60S ALONG THE SOUTHEAST FLORIDA COAST BY DAYBREAK TUESDAY
MORNING.
LONG TERM (WEDNESDAY-SUNDAY)...
THE LATEST EXTENDED GUIDANCE REMAINS IN GOOD AGREEMENT THROUGH THE
SECOND HALF OF THE WEEK AND INDICATES WARM AND HUMID CONDITIONS
RETURNING AS HIGH PRESSURE NORTH OF THE AREA QUICKLY TRANSLATES
EASTWARD OVER THE WESTERN ATLANTIC AND UPPER HEIGHTS BEGIN TO RISE.
TEMPERATURES WILL RESPOND AND QUICKLY RETURN TO WELL ABOVE NORMAL
EACH DAY (10-15 DEG ABOVE NORMAL FRIDAY THROUGH WEEKEND).
MARINE...
A COLD FRONT WILL APPROACH AND MOVE INTO THE LOCAL AREA LATER THIS
EVENING THROUGH MONDAY BEFORE MOVING THROUGH. RAIN CHANCES ALONG
WITH A FEW THUNDERSTORMS CAN BE ANTICIPATED THROUGH THIS TIME ACROSS
THE MARINE AREAS. WINDS AND SEAS MAY APPROACH ADVISORY LEVELS
THROUGH THE FIRST PORTION OF THE WEEK IN THE WAKE OF THE BOUNDARY
AS HIGH PRESSURE BUILDS EASTWARD ACROSS THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 62 74 58 / 40 30 20 10
FORT LAUDERDALE 84 66 75 63 / 40 30 20 10
MIAMI 85 67 75 62 / 40 20 20 20
NAPLES 82 58 72 51 / 90 20 - 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...54/BNB
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1015 AM EST Sun Dec 15 2013
Updated near term and aviation discussions.
.NEAR TERM [Rest of Today]...
Post-frontal rain showers are quickly coming to an end over the
eastern Florida Big Bend and should be out of the forecast area
completely by 16z. Behind the scattered showers, an expansive area
of low stratus still exists well back to the northeast. The 12z
BMX sounding in central Alabama showed a saturated layer beneath a
pronounced frontal inversion. The depth of the saturated layer was
about 2500 feet, so it should take some time to scour out the
stratus behind the front today, although drier air mixing from
aloft should eventually scatter things out. Also working against a
more rapid decrease in stratus is a large arc of cirrostratus
along the upper level jet axis. This interceding cloud layer will
limit the amount of insolation for now.
Thus, with expected cloudy conditions into the afternoon, the
temperature forecast was nudged down a bit. Most areas will have
already seen their highs for the day or are experiencing them
right about now. We followed a blend of our local CAM ensemble and
the HRRR for hourly temperatures for the rest of the day. Much of
the afternoon should see fairly steady temperatures around 50 in
most parts of the area.
&&
.SHORT TERM [Tonight through Tuesday]...
The large scale regional pattern commences tonight with closed low
over Nrn Great Lakes with broad trough over Ern states with
decreasing amplitude N-S leaving only weak cyclonic flow over NE
Gulf region. Upstream ridge with NW steering flow and strong
subsidence overspreading Gulf region from W-E. At surface,
Saturday`s cold front in FL Straits with high building over E/S TX
with cooler and drier air overspreading local area. This reflected
in model soundings which show NW flow surface to H8 then WSW flow
above with PWATS around 0.3 inches.
During the rest of the period, several shortwaves dig across Nrn
Great Lakes keeping trough anchored over Ern states thru Mon before
another low moves Ewd across Great Lakes pushing initial low
Ewd of Canadian Maritimes with trough nudged into Atlc. Surface high
shifts Ewd to over N/Cntrl Gulf Mon and to NE Gulf on Tues allowing
local winds to progressively decouple. With high still to our NW
tonight, pressure gradient just tight enough for non-ideal
radiational cooling. However with high very close to local area Mon
night and near calm winds...min temps will drop another degree or
two especially east of Apalachicola River. Airmass remains bone dry
with PWATS hovering around 0.30 thru period.
Will go with lows tonight from around 32 NW AL counties to mid-upper
30s SE Big Bend or around 5 degrees below normal. Expect lows Mon
night in low 30s everywhere. A brief light freeze is possible
tonight NW most AL counties and Mon night mainly FL Big Bend. Local
confidence tool with 50-90% chance of light freeze NW AL tonight but
freeze area very small and for at best two hours so will hold off on
issuing any product. Wind chills 28 to 31 degrees tonight and 31 to
33 Mon night. Sheltered areas...especially Ern counties...likely to
see patchy frost both nights, predawn into sunrise. Highs Mon around
60 increasing Tues to at or above normal...upper 60s. Expect cloud
free period.
&&
.LONG TERM [Tuesday Night through Saturday]...
High pressure will dominate for most of the extended period with
drier air and moderating temperatures. Once the high moves off to
the northeast Friday, onshore flow will return resulting in a
slight chance of showers.
&&
.AVIATION...
[through 18z Monday] The latest model guidance suggests that
stratus layer may be more persistent than earlier thought, with
MVFR restrictions possible into the early-mid afternoon before the
clouds scatter out. Will amend the TAFs to reflect this change.
Generally VFR expected at all terminals by 21z.
&&
.MARINE...
Northwest winds will continue to increase into this morning
behind the cold front, reaching advisory levels west of
Apalachicola. A Small Craft Advisory remains in effect for those
areas, and a SCEC headline will be maintained east. Winds will
continue to veer to the north later today and remain at SCEC
levels everywhere into Monday before gradually diminishing as
high pressure builds in.
&&
.FIRE WEATHER...
Dry conditions will prevail for the next several days, with relative
humidity levels remaining above critical thresholds. Dispersions
will likely remain within acceptable ranges as well, thus, hazardous
fire weather conditions are not expected.
&&
.HYDROLOGY...
Despite yesterday`s rainfall, gauges have only detected slight rises
on area rivers which still remain well below action stage at most
sites. Significant rainfall is not expected until perhaps next
weekend, so further decline or steady river levels can be expected
through the week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 60 33 62 32 69 / 20 0 0 0 0
Panama City 54 39 60 39 66 / 10 0 0 0 0
Dothan 49 33 60 34 67 / 0 0 0 0 0
Albany 54 33 60 32 67 / 0 0 0 0 0
Valdosta 62 34 61 33 68 / 20 0 0 0 0
Cross City 61 35 64 33 68 / 50 0 0 0 0
Apalachicola 61 41 60 40 65 / 50 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...SMALL CRAFT ADVISORY until 3 PM EST this afternoon for Coastal
waters from Apalachicola to Destin FL out 60 NM.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Block
LONG TERM...Weston
AVIATION...Lamers
MARINE...Block
FIRE WEATHER...Camp
HYDROLOGY...Evans
AREA FORECAST DISCUSSION
NWS MIAMI FL
930 AM EST SUN DEC 15 2013
.UPDATE...
SHOWERS AND A COUPLE OF THUNDERSTORMS ARE MOVING INTO THE
NORTHWESTERN PORTION OF SOUTH FLORIDA THIS MORNING. HAVE BOOSTED
POPS TO REFLECT THIS AND TRANSLATED THE LINE TO THE SOUTH EAST.
THIS IS A PRE-FRONTAL TROUGH, AHEAD OF THE APPROACHING COLD FRONT,
WHICH IS CURRENTLY OVER CENTRAL FLORIDA. THE SHOWERS DO APPEAR AS
THOUGH THEY ARE HAVING TROUBLE KEEPING TOGETHER ACROSS THE
MAINLAND, AND ALMOST FALLING APART ON THE EAST COAST. HOWEVER,
GIVEN DAYTIME HEATING WILL HELP INSTABILITY, HAVE BUMPED UP POPS
FURTHER SOUTH AS WELL. THE QUESTION IS, THIS AFTERNOON, AND IF
THE LINE WILL HOLD TOGETHER ENOUGH TO CONTINUE SHOWERS AND
THUNDERSTORMS.
AS FAR A THUNDERSTORMS ACROSS THE AREA, THIS MORNINGS SOUNDING
DOES SHOW ALMOST 3000 JOULES OF CAPE OVER MIAMI. HOWEVER, THIS
HIGHER CAPE WILL BE PUSHED OUT OF THE AREA AS THE TROUGH CONTINUES
TO APPROACH. HOWEVER, THE FRONT DOES LOOK AS THOUGH IT MAY CATCH
UP TO THE LARGER LINE OF SHOWERS, HELPING TO PUSH IT THROUGH
QUICKER THAN IT CURRENTLY IS. THIS COULD HELP TO PROVIDE THE
TRIGGER FOR SOME ISOLATED STORMS THIS AFTERNOON.
THE HRRR DOES SHOW THE LINE WEAKENING AS IT APPROACHES THE MIAMI
METRO AREA, ALTHOUGH STILL SHOWS IT BRINGING A LINE OF SHOWERS
THROUGH. TIMING IS CURRENTLY INTO THE WEST PALM BEACH METRO AREA
AROUND 16Z, THE BROWARD METRO AREAS AROUND 18 OR 19Z, AND THE
MIAMI METRO AREA BETWEEN 19 AND 20Z. OF COURSE GIVE OR TAKE SOME A
LITTLE TIME, SO HAVE CHANCE POPS FROM 18Z THROUGH 00Z, ALTHOUGH
MOST LIKELY WILL HAVE TO ADJUST IN A FEW HOURS.
&&
.PREV DISCUSSION... /ISSUED 650 AM EST SUN DEC 15 2013/
AVIATION...
SOUTHWESTERLY WINDS ARE EXPECTED AT ALL TAF SITES TODAY. WITH THE
COLD FRONT MOVING SOUTHWARD ACROSS THE FLORIDA PENINSULA THERE IS
A CHANCE OF SHOWERS THIS AFTERNOON AND EVENING AT ALL TAF SITES.
THERE IS ALSO A SLIGHT CHANCE OF THUNDERSTORMS. THE CONFIDENCE OF
THUNDERSTORMS IS LOW SINCE IT IS NOT CLEAR WITH THE LACK OF STRONG
FORCING AND WEAK LAPSE RATES IF THE THUNDERSTORMS WILL SURVIVE AS
THEY CONTINUE TO MOVE SOUTHWARD OR MOVE FROM THE GULF TO THE LAND. FOR
NOW, INCLUDED VCSH FOR ALL TAF SITES AFTER 17Z. THE CEILING AND
VIS SHOULD MOSTLY STAY IN THE VFR CONDITIONS FOR THE DAYTIME HOURS
TODAY...BUT COULD FALL DOWN INTO THE MVFR CONDITIONS WITH ANY
PASSING SHOWERS.
PREV DISCUSSION... /ISSUED 244 AM EST SUN DEC 15 2013/
SHORT TERM (TODAY-TUESDAY)...
RECENTLY ANIMATED WATER VAPOR LOOP SHOWED A BROAD LONG WAVE TROUGH
PROGRESSING EASTWARD TOWARD THE EAST COAST AND PLENTY OF MID/UPPER
MOISTURE SPREADING ENE AHEAD OF IT ACROSS THE REGION. THE EARLY
MORNING SURFACE ANALYSIS SHOWED A COLD FRONT ASSOCIATED WITH THIS
UPPER FEATURE EXTENDING SOUTHWEST ACROSS THE FLORIDA PANHANDLE TO
THE CENTRAL GULF OF MEXICO WITH LIGHT TO MODERATE SOUTHERLY FLOW
ACROSS MUCH OF THE STATE. DEW POINTS ALONG AND AHEAD OF THIS BOUNDARY
RANGED FROM THE UPPER 60S ACROSS CENTRAL FLORIDA TO THE LOWER 70S
ACROSS THE SOUTHERN EXTENT OF THE PENINSULA. THE LATEST SHORT-RANGE
NUMERICAL GUIDANCE REMAINS IN GOOD AGREEMENT AND INDICATES THIS
FRONTAL BOUNDARY CONTINUING ESE THROUGH THE LOCAL AREA LATER THIS
EVENING THROUGH TONIGHT. RAIN CHANCES WILL STEADILY INCREASE ACROSS
THE AREA THROUGH THE DAY...MAINLY ALONG AND AHEAD OF THIS
APPROACHING BOUNDARY. DESPITE THE AMPLE MOISTURE IN PLACE ALONG WITH
THE APPROACHING BOUNDARY...LIMITED FORCING AND POOR LAPSE RATES WILL
LIMIT THUNDERSTORM PROBABILITIES TODAY ACROSS THE LOCAL AREA. FOR
NOW...WE WILL CONTINUE TO INCLUDE ISOLATED TSTMS IN THIS GRIDDED
PACKAGE AND UPDATE AS CONDITIONS EVOLVE TODAY. MODEL RAINFALL
ACCUMULATIONS THROUGH TONIGHT REMAIN LIGHT WITH VALUES RANGING FROM
A TENTH TO A HALF OF AN INCH ACROSS THE AREA. AS TYPICALLY
OBSERVED...LOCALIZED HIGHER AMOUNTS WILL REMAIN POSSIBLE IN ANY
HEAVIER ACTIVITY THAT DEVELOPS OR BECOMES CONCENTRATED.
MONDAY THROUGH TUESDAY...THE DEEP LAYER MOISTURE AXIS ASSOCIATED
WITH THE FRONTAL BOUNDARY EXTENDING SOUTHWEST ACROSS SRN FLORIDA
PENINSULA WILL KEEP A SLIGHT CHANCE OF SHOWERS IN THE FORECAST
THROUGH THE DAY MONDAY. MONDAY NIGHT THROUGH TUESDAY...DRIER AND
COOLER AIR WILL BEGIN TO OVERSPREAD THE LOCAL AREA IN THE WAKE OF
THE BOUNDARY AS HIGH PRESSURE BUILDS EASTWARD ALONG THE NORTHERN
GULF COAST STATES. THE SHORT-RANGE TEMPERATURE GUIDANCE INDICATES
OVERNIGHT LOWS RANGING FROM THE MID 40S ACROSS GLADES COUNTY TO THE
LOWER 60S ALONG THE SOUTHEAST FLORIDA COAST BY DAYBREAK TUESDAY
MORNING.
LONG TERM (WEDNESDAY-SUNDAY)...
THE LATEST EXTENDED GUIDANCE REMAINS IN GOOD AGREEMENT THROUGH THE
SECOND HALF OF THE WEEK AND INDICATES WARM AND HUMID CONDITIONS
RETURNING AS HIGH PRESSURE NORTH OF THE AREA QUICKLY TRANSLATES
EASTWARD OVER THE WESTERN ATLANTIC AND UPPER HEIGHTS BEGIN TO RISE.
TEMPERATURES WILL RESPOND AND QUICKLY RETURN TO WELL ABOVE NORMAL
EACH DAY (10-15 DEG ABOVE NORMAL FRIDAY THROUGH WEEKEND).
MARINE...
A COLD FRONT WILL APPROACH AND MOVE INTO THE LOCAL AREA LATER THIS
EVENING THROUGH MONDAY BEFORE MOVING THROUGH. RAIN CHANCES ALONG
WITH A FEW THUNDERSTORMS CAN BE ANTICIPATED THROUGH THIS TIME ACROSS
THE MARINE AREAS. WINDS AND SEAS MAY APPROACH ADVISORY LEVELS
THROUGH THE FIRST PORTION OF THE WEEK IN THE WAKE OF THE BOUNDARY
AS HIGH PRESSURE BUILDS EASTWARD ACROSS THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 62 74 58 / 70 30 20 10
FORT LAUDERDALE 84 66 75 63 / 60 30 20 10
MIAMI 85 67 75 62 / 60 20 20 20
NAPLES 82 58 72 51 / 90 20 - 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...54/BNB
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
315 AM EST SUN DEC 15 2013
.DISCUSSION...
...SHOWERS AND ISOLATED LIGHTNING STORMS TODAY BEFORE A COLD FRONT
MOVES THROUGH THE AREA BRINGING COOLER AIR TO START THE WEEK...
TODAY...SFC LOW PRESSURE WILL MOVE NE UP THE EASTERN SEABOARD TODAY
AND PULL A COLD FRONT THROUGH THE AREA THIS AFTERNOON. PRE-FRONTAL
CONVECTIVE BAND WILL MOVE ACROSS THE NRN FORECAST AREA THIS MORNING
WITH ADDITIONAL SHOWERS AND ISOLATED LIGHTNING STORMS AHEAD OF THE
FRONT ACROSS SRN AREAS INTO LATE AFTERNOON. MAIN LIGHTNING STORM
HAZARDS WILL BE GUSTY WINDS TO 45 MPH...LOCALLY HEAVY RAIN AND
OCCASIONAL CLOUD TO GROUND LIGHTNING STRIKES. HRRR MODEL INDICATES
CONVECTIVE LINE ACROSS FAR NRN SECTIONS WILL WEAKEN AS IT PUSHES
SOUTH TOWARD ORLANDO THROUGH MID MORNING AND APPEARS ADDITIONAL
STORMS CURRENTLY OVER THE LOOP CURRENT AND APPROACHING THE SW FL
COAST WILL AFFECT SRN AREAS THIS AFTERNOON BEFORE THE COLD FRONT
MOVES SOUTH OF THE AREA. S-SW WINDS WILL BECOME NW BEHIND THE FRONT
THIS AFTERNOON. HIGHS WILL BE IN THE LOWER 70S FAR NORTH TO THE
LOWER 80S FROM VERO BEACH SOUTH.
TONIGHT...FRONT WILL MOVE TOWARD THE BAHAMAS AND S FL DURING THE
EARLY EVENING SOME MID AND HIGH CLOUDINESS WILL LINGER BEHIND THE
SFC BOUNDARY WITH CLEARING LATE. THINK MOST OF THE SHOWER ACTIVITY
WILL HAVE MOVED OFF INTO THE ATLC BY EARLY EVENING. NW-N WINDS WILL
USHER IN COOLER AIR. LOWS WILL BE IN THE 40S NW OF I-4 CORRIDOR TO
THE LOWER 50S AT MELBOURNE AND VERO BEACH AND AROUND 60 ALONG THE
MARTIN COUNTY COAST.
MON-MON NIGHT...THE COLD FRONT CLEARS SOUTH FLORIDA DURING THE DAY.
HIGH PRESSURE BUILDING EASTWARD ALONG THE NORTHERN GULF COAST WILL
KEEP WINDS OUT OF THE NORTH/NORTHEAST DURING THE DAY MONDAY. THIS
WILL CONTINUE TO TRANSPORT DRIER AND COOLER AIR OVER THE AREA. HIGHS
WILL BE SEVERAL DEGREES BELOW NORMAL EVEN UNDER SUNNY
SKIES...RANGING FROM THE MID TO UPPER 60S NORTH OF MELBOURNE TO
AROUND 70/LOW 70S FARTHER SOUTH. LIGHTER WINDS MONDAY NIGHT AND
CLEAR SKIES WILL GENERATE FAVORABLE RADIATIONAL COOLING CONDITIONS
WITH TEMPS DROPPING TO VALUES NEAR TO PERHAPS EVEN A FEW DEGREES
LOWER THAN EARLY MONDAY MORNING.
TUE-FRI...HIGH PRESSURE OVER THE NRN GULF COAST WILL EXTEND OVER THE
SOUTHEAST U.S. AND EVENTUALLY OFFSHORE LATE IN THE WEEK. AS THE
CENTER OF THE HIGH PRESSURE SYSTEM TRACKS EASTWARD WINDS WILL
INITIALLY BE OUT OF THE NORTH TO NORTHEAST THROUGH MID WEEK THEN
SHIFT TO ONSHORE LATE IN THE WEEK. COOLER MORNING TEMPERATURES EARLY
TUESDAY WILL BEGIN A SLOW MODIFICATION AND WARMING TREND THROUGH THE
REST OF THE WEEK AS THE WINDS BECOME MORE ONSHORE. LOWS MODERATING
IN THE 50S THURSDAY MORNING AND THE MID 50S TO LOW 60S MELBOURNE
COCOA BEACH SOUTH BY FRIDAY SUNRISE.
&&
.AVIATION...MVFR CIGS FROM 015-025 WILL ENCROACH ON NRN TERMINALS
THROUGH THE MID MORNING WITH SHRA AND PSBL ISOLD TSRA EXPECTED NORTH
OF KISM-KTIX LINE TROUGH 15Z. ADDITIONAL SHRA/ISOLD TSRA WILL MOVE E
ACROSS SRN PORTIONS OF E CENTRAL FL LIKELY AFFECT TERMINALS FROM
KMLB-KSUA BY MID DAY INTO THE AFTERNOON. WINDS WILL BECOME NW THIS
AFTERNOON BEHIND THE FRONT WITH VFR MID LVL CIGS INTO THIS EVENING.
&&
.MARINE...SW WINDS TO 20 KNOTS OFFSHORE THIS MORNING WILL BECOME NW
THIS AFTERNOON AS A SFC COLD FRONT MOVES DOWN ACROSS THE WATERS.
WILL EXTEND THE ADVISORY FOR THE OFFSHORE WATERS INTO EARLY
AFTERNOON. NNW/N WINDS TONIGHT TO 15-20 KNOTS OFFSHORE WILL LIKELY
REQUIRE SCEC OR SCA HEADLINES FOR THE GULF STREAM AND OFFSHORE
WATERS. MON-THU...NORTHERLY WINDS UP TO 15 TO 20 KNOTS BEHIND THE
FRONT WILL PRODUCE POOR TO HAZARDOUS BOATING CONDITIONS MONDAY WITH
SEAS UP TO 7 FEET IN THE GULF STREAM. NORTHERLY WINDS WILL THEN
DECREASE AND VEER TO THE NORTH/NORTHEAST TUE/WED BEFORE BECOMING
ONSHORE AND INCREASING ONCE AGAIN LATE IN THE WEEK.
&&
.FIRE WEATHER...TODAY...SW WINDS WILL SWITCH TO THE NW THIS
AFTERNOON AS A COLD FRONT MOVES THROUGH THE AREA. SCATTERED SHOWERS
AND ISOLATED LIGHTNING STORMS EXPECTED INTO THIS AFTERNOON BEFORE
THE FRONT CLEARS THE AREA BY EARLY EVENING. MON...DRIER AIRMASS WILL
BUILD INTO THE AREA BEHIND THE COLD FRONT INTO EARLY THIS WEEK. RH
VALUES FORECAST TO FALL INTO THE LOWER 30S ALONG AND WEST OF THE I-4
CORRIDOR MONDAY AND TUESDAY AFTERNOONS BUT LOWER ERC VALUES AND 20
FT WIND SPEEDS SHOULD PRECLUDE ANY FIRE WEATHER WATCHES/WARNINGS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 73 46 65 44 / 60 0 0 10
MCO 77 49 67 45 / 50 10 0 10
MLB 79 52 69 50 / 50 10 10 10
VRB 82 56 70 52 / 50 10 10 10
LEE 72 45 65 43 / 60 0 0 10
SFB 75 48 67 45 / 60 10 0 10
ORL 76 50 66 48 / 60 10 0 10
FPR 82 58 71 52 / 50 10 10 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR WATERS
FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60
NM OFFSHORE-WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20
TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE
TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
&&
$$
SHORT TERM/AVIATION...VOLKMER
LONG TERM....WIMMER
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
836 PM CST MON DEC 16 2013
.DISCUSSION...
830 PM CST
CHARACTERISTIC OF THIS YOUNG 2013-2014 WINTER...ONE WEATHER ISSUE
DEPARTS AND ANOTHER QUICKLY FOLLOWS ON ITS HEELS. NOT ONLY IS THAT
NEXT ISSUE THE BRIEF SHOT OF SNOW TUESDAY MORNING...BUT ALSO
FREEZING FOG FOR AREAS ALONG AND SOUTH OF HIGHWAY 24 DURING THIS
EVENING. WE ISSUED A SPECIAL WEATHER STATEMENT FOR BOTH.
GOES WATER VAPOR SATELLITE AND UPPER AIR ANALYSES INDICATE THE
SHORT WAVE OF THE EARLIER SNOW IS HEADING EAST OVER LAKE MI ON A
STRONG 80 KT 500MB JET MAX. THE MAIN PRESSURE FALLS ARE LOCATED
EVEN FURTHER NORTH ACROSS THE FAR NORTHERN GREAT LAKES...SO THE
SURFACE REFLECTION ACROSS OUR AREA HAS BEEN WEAK. THIS HAS HELPED
ALLOW FOR SATURATION IN THE LOW-LEVELS AND THE INABILITY TO ADVECT
IT AWAY. BOTH THE 00Z DVN AND ILX SOUNDINGS SHOWED STRONG
INVERSIONS OF AROUND 7C WITH NEARLY COMPLETE SATURATION BELOW.
SATELLITE AND OBSERVATIONS CORRELATE WITH THIS LOW-LEVEL MOISTURE
WELL...DEPICTING LOW VISIBILITIES ACROSS CENTRAL IL.
LAW ENFORCEMENT HAS REPORTED THIS ALONG WITH ICY ROADS IN FORD AND
BENTON COUNTIES AS TEMPERATURES ARE WELL BELOW FREEZING. ITS NOT
IMPOSSIBLE THERE IS A LITTLE DRIZZLE IN THIS MUCK AS WELL GIVEN
THE DECENT WIND FLOW AND SLIGHT ASCENT AT AND JUST ABOVE THE
INVERSION LEVEL. EVENTUALLY WESTERLY SURFACE WINDS DO INCREASE
SOME AS THE PRESSURE GRADIENT TIGHTENS OVERNIGHT. RAP AND HRRR
VISIBILITY AND CIG FORECAST DO TRY TO SHOW THE VERY LOW SATURATION
ADVECTING EAST BY EARLY OVERNIGHT AND THAT SEEMS
REASONABLE...THOUGH THEY COULD BE A LITTLE HASTY WITH THAT. GIVEN
THE SOMEWHAT LIMITED EXPECTED DURATION AND REPORTS OF VISIBILITY
NOT BEING AS LOW AS ONE QUARTER MILE IN OUR FORECAST AREA...HAVE
JUST GONE WITH AN SPS AS OPPOSED TO AN ADVISORY.
NEXT QUICK MOVING CLIPPER IS SEEN IN NW MN ON WATER VAPOR AND IS
ON A PATH FOR THE CWA BY DAYBREAK. THE GOING TIMING IN THE GRIDS
LOOKS GREAT COMPARED TO SHORT TERM/HIGH RES GUIDANCE WHICH SEEMED
TO HAVE HANDLED TODAYS SIMILAR EVENT WELL. RATIOS LOOK HIGHER WITH
THE TUE MORNING EVENT THAN TODAY...AND THE LATEST LOCAL 8KM ARW
DOES SHOW A COUPLE HOURS OF NEAR 25:1 RATIOS WHICH MAY BE A BIT
HIGH...BUT DO AT LEAST INDICATE THAT BURST POTENTIAL DURING RUSH
HOUR. TIMING AND MAGNITUDE OF WIND GUST INCREASE STILL LOOKS
REPRESENTATIVE AND THE FORECAST SPEEDS SHOULD BE ENOUGH TO
REALIZE PATCHY BLOWING OF THE FRESH SNOWFALL IN OPEN AREAS.
MTF
//PREV DISCUSSION...
305 PM CST
NUMEROUS FORECAST CONCERNS GOING THROUGH THE WEEKEND AS THE UPPER
FLOW PATTERN SHIFTS FROM FAVORING NORTHWEST FLOW AND PERIODIC
CLIPPERS TO A SOUTHWESTERLY FLOW SUPPORTING A BRIEF WARM UP FOLLOWED
BY THE POTENTIAL FOR STRONGER SOUTHWEST SYSTEMS.
EARLY AFTERNOON WATER VAPOR IMAGERY SHOWS A BROAD TROUGH OVER MOST
OF THE U.S. WITH BROAD RIDGING COMING OVER THE WEST COAST OF NORTH
AMERICA. EMBEDDED IN THE BROAD TROUGH ARE A SERIES OF WAVES...THE
FIRST OF WHICH IS ENTERING THE LOCAL AREA BRINGING BANDS OF SNOW.
THE NEXT WAVE OF NOTE IS MORE SUBTLE AS IT MOVES SOUTHEAST ACROSS
THE CENTRAL ALBERTA/SASKATCHEWAN BORDER AND GENERATES SNOW INTO
NORTHEASTERN MONTANA. THIS WAVE WILL MOVE INTO THE LOCAL AREA
TOMORROW MORNING. OTHERWISE...THE PATTERN WILL BECOME LESS AMPLIFIED
DURING MID WEEK AS THE MAIN UPPER TROUGH PUSHES EAST FOLLOWED BY THE
BROAD RIDGING CURRENTLY TO THE WEST.
TONIGHT AND TUESDAY...THE CURRENT CLIPPER WILL BE DEPARTING THE AREA
THROUGH THE EARLY EVENING HOURS BRINGING SNOW TO AN END AND TURNING
WINDS WESTERLY. ATTENTION TURNS TO THE MORE SUBTLE WAVE MOVING
SOUTHEAST ACROSS THE CENTRAL ALBERTA/SASKATCHEWAN BORDER AND A
SURFACE LOW TO THE EAST OF THE WAVE OVER MANITOBA WHICH WILL ALSO
MOVE SOUTHEAST WITH THE CENTER TRACKING INTO WESTERN ONTARIO TUESDAY
MORNING. A COLD FRONT WILL TRAIL THE LOW AND PUSH ACROSS THE LOCAL
AREA DURING THE MORNING. ANOTHER ROUND OF SNOW WILL LIKELY ACCOMPANY
THE PASSAGE OF THE UPPER WAVE AND SURFACE COLD FRONT. GUIDANCE
CONTINUES TO SHOW A RANGE OF SOLUTIONS WITH THE EXTENT/AMOUNT OF THE
PRECIP ACROSS THE AREA BUT GENERALLY HAS BEEN MORE BULLISH WITH
SNOWFALL COVERAGE OVER THE AREA THAN EARLIER RUNS. THIS FALLS IN
LINE WITH THE OBSERVED TRENDS OF THE CLIPPER LAST NIGHT AND THE ONE
CURRENTLY CROSSING THE AREA AND SEE LITTLE TO SUPPORT HAVING
DIFFERENT EXPECTATIONS FOR THIS NEXT ONE. WILL CONTINUE WITH THE
HIGH POPS ACROSS THE NORTHERN QUARTER TO THIRD OF THE AREA...WITH
THE FOCUS FOR MOST INTENSE AND LONGEST DURATION OF SNOW ALONG AND
NORTH OF A ROCKFORD TO CHICAGO TO VALPARAISO LINE...WHILE LIGHTER
SNOW FALLS TO THE SOUTH OF THIS LINE. THE UPPER WAVE LOOKS TO BE
SLIGHTLY WEAKER THAN THE ONE CURRENTLY CROSSING THE AREA BUT DOES
LOOK TO STRENGTHEN A BIT AS IT APPROACHES IN CONJUNCTION WITH A
BETTER ALIGNMENT OF THE LEFT EXIT OF AN UPPER JET. MODEL GUIDANCE
SHOWS A RANGE OF SNOWFALL AMOUNTS FROM VERY LITTLE TO A FEW INCHES
AND EVEN DIFFERS IN THE MAGNITUDE OF FORCING RELATIVE TO THE FAVORED
CRYSTAL GROWTH REGION. AT THIS POINT FEEL THE BEST ROUTE IS TO STICK
WITH THE OBSERVED TRENDS OF RECENT CLIPPERS AND ACCOUNT FOR THE
EXPECTATION OF SOME BETTER ORGANIZATION OF THE UPPER WAVE AND
FAVORED JET PLACEMENT. WITH THIS IN MIND FEEL THAT IT IS LIKELY THAT
NORTHERN PORTIONS OF THE AREA WILL SEE ANOTHER 1 TO POSSIBLY 2 INCH
EVENT WITH HIGH SNOW RATIOS. STEEP MID LEVEL LAPSE RATES AND GOOD
FORCING IN THE SNOW GROWTH ZONE SIMILAR TO TODAY SUPPORT
ACCUMULATION RATES OF 0.5 TO 0.75 IN/HR. CONTINUED WITH A SNOW RATIO
OF 16-18:1 OVERALL. MAY BE ABLE TO USE AMOUNTS/RATIOS/RATES FROM THE
CURRENT SNOW TO BETTER REFINE FOR THE MORNING. TIMING-WISE...SNOW
SHOULD MOVE INTO THE NORTHWEST PART OF THE AREA TOWARD DAYBREAK AND
THE CHICAGO METRO RIGHT AROUND OR JUST AFTER DAYBREAK THEN EXIT TO
THE EAST DURING THE LATE MORNING HOURS. THE PASSAGE OF THE COLD
FRONT WILL BRING A SHIFT TO NORTHWEST WINDS WHICH WILL INCREASE WITH
GUSTS PUSHING 35-40 MPH FROM LATE MORNING THROUGH THE AFTERNOON
LEADING TO BLOWING SNOW. HIGHS SHOULD BE RIGHT AROUND 30...THOUGH
THERE COULD BE A SLIGHT DECREASE IN TEMPS IN THE AFTERNOON WITH SOME
COOL ADVECTION BUT CLEARING SKIES AND SUNSHINE MAY OFFSET THIS. LOWS
TUESDAY NIGHT SHOULD FALL INTO THE MID TEENS WITH WINDS DIMINISHING
AND TURNING SOUTHWEST.
WEDNESDAY THROUGH FRIDAY...THE UPPER TROUGH CARVED OUT BY THE SERIES
OF CLIPPERS WILL SWING TO THE EAST AND OFF THE NEW ENGLAND COAST
WEDNESDAY ALLOWING FOR BROAD UPPER RIDGING TO SPREAD ACROSS THE
U.S. THIS WILL BRING A PUSH OF MID LEVEL WARM ADVECTION TO THE
REGION WEDNESDAY INTO THURSDAY WITH H85 TEMPS WARMING TO AROUND +6C
OR SO AND H92 TEMPS WARMING JUST ABOVE 0C. THIS WILL ALLOW FOR
SURFACE WARMING AS WELL BUT SNOW COVER WILL BE ONE LIMITING FACTOR.
TEMPS WEDNESDAY WILL BE TRICKY BECAUSE ASIDE FROM SOME MID LEVEL WAA
CLOUDS EARLY THERE WILL LIKELY BE AT LEAST SOME SUN AS WELL AS A
STRONG SOUTHWEST WIND. BOTH OF THESE POINT TOWARD WARMER HIGHS GIVEN
THAT THE LOWER ATMOSPHERE WILL STILL BE RELATIVELY DRY. THIS SHOULD
ALLOW MOST AREAS TO WARM TO OR JUST ABOVE FREEZING. BY THURSDAY...AN
UPPER TROUGH WILL BE WORKING INTO THE WESTERN U.S. WITH THE UPPER
FLOW SPLITTING INTO TWO STREAMS AS THE TROUGH DIGS SOUTH AND CUTS
OFF OVER OR JUST OFF THE CALIFORNIA COAST. HEIGHT FALLS AHEAD OF
THIS TROUGHING WILL LEAD TO SURFACE LOW PRESSURE DEVELOPMENT ACROSS
THE CENTRAL/SOUTHERN ROCKIES WITH AN INVERTED TROUGH AXIS EXTENDING
NORTHEAST ACROSS THE LOCAL AREA. DEEP LAYER MOISTURE WILL BE
INCREASING THURSDAY LEADING TO PRECIP CHANCES...ESPECIALLY LATER IN
THE DAY WITH LOW LEVEL MOIST ADVECTION ACTING ON THE SNOW PACK TO
LIKELY GENERATE FOG. THIS WILL PROBABLY KEEP TEMPS IN THE MID TO
UPPER 30S. PRECIP MAY END UP BEING MORE DRIZZLE THAN FALLING PRECIP
THROUGH THE DAY AND POSSIBLY THE EVENING/OVERNIGHT. THE UPPER FLOW
LOOKS TO REMAIN SPLIT WITH NORTHERN STREAM ENERGY KICKING THE
SURFACE LOW NORTHEAST RIGHT ACROSS THE AREA THURSDAY NIGHT AND
FRIDAY MORNING. THIS WILL ALSO BRING A COLD FRONT THOUGH THE AREA
EARLY FRIDAY. ANY RAIN WILL LIKELY TURN TO A MIX OR ALL SNOW FRIDAY
MORNING. OVERALL PRECIP AMOUNTS LOOK LIGHT WITH WEAK OR DISJOINTED
FORCING. HIGHS FRIDAY WILL LIKELY BE EARLY THEN FALL THROUGH THE
DAY.
SATURDAY THROUGH MONDAY...THIS PERIOD BEARS WATCHING AS ENERGY FROM
THE SOUTHERN STREAM CUTOFF UPPER LOW IS EXPECTED TO KICK NORTHEAST
THIS WEEKEND AS A REINFORCING UPPER TROUGH MOVES SOUTHEAST INTO THE
NORTHERN PLAINS. THIS WILL LIKELY SEND A SURFACE LOW AND/OR INVERTED
TROUGH NORTHEAST WITH RECENT GUIDANCE BRINGING IT SOUTHEAST OF THE
AREA. RIGHT NOW THE FAVORED TIME FOR THE SYSTEM TO BRING PRECIP TO
THE AREA WOULD BE LATER SATURDAY INTO SUNDAY. GIVEN THE PRECEDING
SHIFT IN THE UPPER FLOW TO A MORE ZONAL PATTERN AHEAD OF THE
TROUGHED FLOW...THERMAL FIELDS WILL BE MORE CRITICAL IN THAT THEY
WILL LIKELY BE WARM ENOUGH FOR A RANGE OF PRECIP TYPES TO OCCUR
DEPENDING ON WHERE THE LOW TRACKS. OVERALL SYSTEM STRENGTH AND
MOISTURE FEED SUPPORT HIGHER END PRECIP AMOUNTS WITH AFFECTED AREAS
DEPENDING ON THE TRACK. STILL VERY EARLY TO HAVE MUCH CONFIDENCE IN
DETAILS GIVEN THE EVOLUTION OF UPPER FLOW THAT NEEDS TO TAKE PLACE
IN THE MEANTIME BUT THERE LOOKS TO BE A GOOD CHANCE FOR A SYSTEM TO
BE AFFECTING THE REGION.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* MVFR CEILINGS...WITH PERIODS OF IFR CEILINGS TONIGHT.
* ANOTHER ROUND OF SNOW EXPECTED BETWEEN 12 AND 16 UTC...WITH LOW
VIS DOWN AROUND 1SM LIKELY.
* STRONG WEST NORTHWEST WINDS DEVELOPING AFTER 16 UTC ON TUESDAY.
RODRIGUEZ
//DISCUSSION...UPDATED 00Z...
WITH THE DEPARTURE OF THIS PAST AFTERNOONS SNOW...A SECOND AREA OF
LIGHT TO MODERATE SNOW HAS DEVELOPED AND CONTINUES TO MOVE OVER
ALL THE TERMINALS AT THIS TIME. ALTHOUGH...THIS SNOW WILL END FROM
WEST TO EAST STARTING THIS UPCOMING HOUR THROUGH THE 2Z TIME
FRAME. IFR VIS WITH A BRIEF PERIOD OF LIFR VIS WILL BE
POSSIBLE...BEFORE CONDITIONS RAPIDLY IMPROVE. MVFR CEILINGS
PREVAIL THIS HOUR ACROSS THE TAF SITES AND EXPECT THESE LOWER
CEILINGS TO HOLD IN PLACE OVERNIGHT. CONTINUE TO MONITOR A SIMILAR
SYSTEM WHICH WILL QUICKLY ARRIVE EARLY TUESDAY MORNING...PROVIDING
A PERIOD OF LIGHT TO MODERATE SNOW THROUGH MID MORNING. SIMILAR
CEILING/VIS TRENDS ARE EXPECTED...WITH CEILINGS HOLDING AT MVFR
AND VIS DROPPING TO AROUND 1 MILE AT TIMES. WEST NORTHWEST WINDS
WILL PICK UP ON THE BACKSIDE OF THIS SYSTEM WITH GUSTS AROUND 30KT
POSSIBLE INTO THE AFTERNOON.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM CONFIDENCE WITH CEILINGS/TRENDS TONIGHT.
* MEDIUM-HIGH CONFIDENCE IN SNOW TUESDAY MORNING.
* MEDIUM CONFIDENCE WITH WIND SPEED/GUSTS TUESDAY.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN W/ FOG.
FRIDAY...CHANCE OF RAIN OR SNOW BECOMING ALL SNOW BY THE
AFTERNOON.
SATURDAY...CHANCE OF SNOW.
SUNDAY...CHANCE OF SNOW.
RODRIGUEZ
&&
.MARINE...
204 PM CST
A SERIES OF DISTURBANCES WILL LEAD TO SEVERAL WIND SHIFTS THROUGH
THE REMAINDER OF THE WEEK...AS WELL AS A BRIEF PERIOD OF GALES WHICH
IS EXPECTED TUESDAY. TODAY HIGH PRESSURE IS STARTING TO DRIFT EAST
OF LAKE MICHIGAN WITH SOUTHWEST FLOW INCREASING IN ADVANCE OF AN
APPROACHING COLD FRONT. THIS FIRST FRONT WILL MOVE ACROSS LAKE
MICHIGAN WITH WINDS VEERING TO WESTERLY OVERNIGHT. A SECOND FRONT
WILL BE RIGHT ON ITS HEELS THOUGH...AND WILL PUSH ACROSS LAKE
MICHIGAN TUESDAY AFTERNOON WITH WINDS SHIFTING NORTHWESTERLY. A
BETTER SURGE OF COLD AIR WILL BE ASSOCIATED WITH THIS SECOND
FRONT...AS WELL AS A TIGHTER PRESSURE GRADIENT WITH A MODERATE RIDGE
BUILDING ALONG THE MISSISSIPPI VALLEY...LEADING TO A PERIOD OF WEST
TO NORTHWEST GALES...PARTICULARLY ACROSS THE SOUTH HALF OF THE LAKE.
GALES WILL DIMINISH TUESDAY NIGHT AND WINDS WILL BEGIN TO BACK TO
THE SOUTHWEST WEDNESDAY AS THE RIDGE PROGRESSES EAST ACROSS LAKE
MICHIGAN. SOUTHWEST WINDS FRESHEN UP AGAIN WEDNESDAY NIGHT AS YET
ANOTHER FRONT IS POISED TO SWEEP ACROSS THE LAKE EARLY THURSDAY.
MODERATE NORTHERLY FLOW IS EXPECTED FRIDAY BEHIND THE FRONT AS
ANOTHER LOW PRESSURE SKIRTS TO THE EAST...JUST SOUTH OF THE
GREAT LAKES.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ744-LMZ745...MIDNIGHT TUESDAY TO 9 AM
TUESDAY.
GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM TUESDAY TO 9 PM TUESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...MIDNIGHT
TUESDAY TO MIDNIGHT WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
831 PM CST MON DEC 16 2013
.DISCUSSION...
830 PM CST
CHARACTERISTIC OF THIS YOUNG 2013-2014 WINTER...ONE WEATHER ISSUE
DEPARTS AND ANOTHER QUICKLY FOLLOWS ON ITS HEELS. NOT ONLY IS THAT
NEXT ISSUE THE BRIEF SHOT OF SNOW TUESDAY MORNING...BUT ALSO
FREEZING FOG FOR AREAS ALONG AND SOUTH OF HIGHWAY 24 DURING THIS
EVENING. WE ISSUED A SPECIAL WEATHER STATEMENT FOR BOTH.
GOES WATER VAPOR SATELLITE AND UPPER AIR ANALYSES INDICATE THE
SHORT WAVE OF THE EARLIER SNOW IS HEADING EAST OVER LAKE MI ON A
STRONG 80 KT 500MB JET MAX. THE MAIN PRESSURE FALLS ARE LOCATED
EVEN FURTHER NORTH ACROSS THE FAR NORTHERN GREAT LAKES...SO THE
SURFACE REFLECTION ACROSS OUR AREA HAS BEEN WEAK. THIS HAS HELPED
ALLOW FOR SATURATION IN THE LOW-LEVELS AND THE INABILITY TO ADVECT
IT AWAY. BOTH THE 00Z DVN AND ILX SOUNDINGS SHOWED STRONG
INVERSIONS OF AROUND 7C WITH NEARLY COMPLETE SATURATION BELOW.
SATELLITE AND OBSERVATIONS CORRELATE WITH THIS LOW-LEVEL MOISTURE
WELL...DEPICTING LOW VISIBILITIES ACROSS CENTRAL IL.
LAW ENFORCEMENT HAS REPORTED THIS ALONG WITH ICY ROADS IN FORD AND
BENTON COUNTIES AS TEMPERATURES ARE WELL BELOW FREEZING. ITS NOT
IMPOSSIBLE THERE IS A LITTLE DRIZZLE IN THIS MUCK AS WELL GIVEN
THE DECENT WIND FLOW AND SLIGHT ASCENT AT AND JUST ABOVE THE
INVERSION LEVEL. EVENTUALLY WESTERLY SURFACE WINDS DO INCREASE
SOME AS THE PRESSURE GRADIENT TIGHTENS OVERNIGHT. RAP AND HRRR
VISIBILITY AND CIG FORECAST DO TRY TO SHOW THE VERY LOW SATURATION
ADVECTING EAST BY EARLY OVERNIGHT AND THAT SEEMS
REASONABLE...THOUGH THEY COULD BE A LITTLE HASTY WITH THAT. GIVEN
THE SOMEWHAT LIMITED EXPECTED DURATION AND REPORTS OF VISIBILITY
NOT BEING AS LOW AS ONE QUARTER MILE IN OUR FORECAST AREA...HAVE
JUST GONE WITH AN SPS AS OPPOSED TO AN ADVISORY.
NEXT QUICK MOVING CLIPPER IS SEEN IN NW MN ON WATER VAPOR AND IS
ON A PATH FOR THE CWA BY DAYBREAK. THE GOING TIMING IN THE GRIDS
LOOKS GREAT COMPARED TO SHORT TERM/HIGH RES GUIDANCE WHICH SEEMED
TO HAVE HANDLED TODAYS SIMILAR EVENT WELL. RATIOS LOOK HIGHER WITH
THE TUE MORNING EVENT THAN TODAY...AND THE LATEST LOCAL 8KM ARW
DOES SHOW A COUPLE HOURS OF NEAR 25:1 RATIOS WHICH MAY BE A BIT
HIGH...BUT DO AT LEAST INDICATE THAT BURST POTENTIAL DURING RUSH
HOUR. TIMING AND MAGNITUDE OF WIND GUST INCREASE STILL LOOKS
REPRESENTATIVE AND THE FORECAST SPEEDS SHOULD BE ENOUGH TO
REALIZE PATCHY BLOWING OF THE FRESH SNOWFALL IN OPEN AREAS.
MTF
&&
.PREV DISCUSSION...
305 PM CST
NUMEROUS FORECAST CONCERNS GOING THROUGH THE WEEKEND AS THE UPPER
FLOW PATTERN SHIFTS FROM FAVORING NORTHWEST FLOW AND PERIODIC
CLIPPERS TO A SOUTHWESTERLY FLOW SUPPORTING A BRIEF WARM UP FOLLOWED
BY THE POTENTIAL FOR STRONGER SOUTHWEST SYSTEMS.
EARLY AFTERNOON WATER VAPOR IMAGERY SHOWS A BROAD TROUGH OVER MOST
OF THE U.S. WITH BROAD RIDGING COMING OVER THE WEST COAST OF NORTH
AMERICA. EMBEDDED IN THE BROAD TROUGH ARE A SERIES OF WAVES...THE
FIRST OF WHICH IS ENTERING THE LOCAL AREA BRINGING BANDS OF SNOW.
THE NEXT WAVE OF NOTE IS MORE SUBTLE AS IT MOVES SOUTHEAST ACROSS
THE CENTRAL ALBERTA/SASKATCHEWAN BORDER AND GENERATES SNOW INTO
NORTHEASTERN MONTANA. THIS WAVE WILL MOVE INTO THE LOCAL AREA
TOMORROW MORNING. OTHERWISE...THE PATTERN WILL BECOME LESS AMPLIFIED
DURING MID WEEK AS THE MAIN UPPER TROUGH PUSHES EAST FOLLOWED BY THE
BROAD RIDGING CURRENTLY TO THE WEST.
TONIGHT AND TUESDAY...THE CURRENT CLIPPER WILL BE DEPARTING THE AREA
THROUGH THE EARLY EVENING HOURS BRINGING SNOW TO AN END AND TURNING
WINDS WESTERLY. ATTENTION TURNS TO THE MORE SUBTLE WAVE MOVING
SOUTHEAST ACROSS THE CENTRAL ALBERTA/SASKATCHEWAN BORDER AND A
SURFACE LOW TO THE EAST OF THE WAVE OVER MANITOBA WHICH WILL ALSO
MOVE SOUTHEAST WITH THE CENTER TRACKING INTO WESTERN ONTARIO TUESDAY
MORNING. A COLD FRONT WILL TRAIL THE LOW AND PUSH ACROSS THE LOCAL
AREA DURING THE MORNING. ANOTHER ROUND OF SNOW WILL LIKELY ACCOMPANY
THE PASSAGE OF THE UPPER WAVE AND SURFACE COLD FRONT. GUIDANCE
CONTINUES TO SHOW A RANGE OF SOLUTIONS WITH THE EXTENT/AMOUNT OF THE
PRECIP ACROSS THE AREA BUT GENERALLY HAS BEEN MORE BULLISH WITH
SNOWFALL COVERAGE OVER THE AREA THAN EARLIER RUNS. THIS FALLS IN
LINE WITH THE OBSERVED TRENDS OF THE CLIPPER LAST NIGHT AND THE ONE
CURRENTLY CROSSING THE AREA AND SEE LITTLE TO SUPPORT HAVING
DIFFERENT EXPECTATIONS FOR THIS NEXT ONE. WILL CONTINUE WITH THE
HIGH POPS ACROSS THE NORTHERN QUARTER TO THIRD OF THE AREA...WITH
THE FOCUS FOR MOST INTENSE AND LONGEST DURATION OF SNOW ALONG AND
NORTH OF A ROCKFORD TO CHICAGO TO VALPARAISO LINE...WHILE LIGHTER
SNOW FALLS TO THE SOUTH OF THIS LINE. THE UPPER WAVE LOOKS TO BE
SLIGHTLY WEAKER THAN THE ONE CURRENTLY CROSSING THE AREA BUT DOES
LOOK TO STRENGTHEN A BIT AS IT APPROACHES IN CONJUNCTION WITH A
BETTER ALIGNMENT OF THE LEFT EXIT OF AN UPPER JET. MODEL GUIDANCE
SHOWS A RANGE OF SNOWFALL AMOUNTS FROM VERY LITTLE TO A FEW INCHES
AND EVEN DIFFERS IN THE MAGNITUDE OF FORCING RELATIVE TO THE FAVORED
CRYSTAL GROWTH REGION. AT THIS POINT FEEL THE BEST ROUTE IS TO STICK
WITH THE OBSERVED TRENDS OF RECENT CLIPPERS AND ACCOUNT FOR THE
EXPECTATION OF SOME BETTER ORGANIZATION OF THE UPPER WAVE AND
FAVORED JET PLACEMENT. WITH THIS IN MIND FEEL THAT IT IS LIKELY THAT
NORTHERN PORTIONS OF THE AREA WILL SEE ANOTHER 1 TO POSSIBLY 2 INCH
EVENT WITH HIGH SNOW RATIOS. STEEP MID LEVEL LAPSE RATES AND GOOD
FORCING IN THE SNOW GROWTH ZONE SIMILAR TO TODAY SUPPORT
ACCUMULATION RATES OF 0.5 TO 0.75 IN/HR. CONTINUED WITH A SNOW RATIO
OF 16-18:1 OVERALL. MAY BE ABLE TO USE AMOUNTS/RATIOS/RATES FROM THE
CURRENT SNOW TO BETTER REFINE FOR THE MORNING. TIMING-WISE...SNOW
SHOULD MOVE INTO THE NORTHWEST PART OF THE AREA TOWARD DAYBREAK AND
THE CHICAGO METRO RIGHT AROUND OR JUST AFTER DAYBREAK THEN EXIT TO
THE EAST DURING THE LATE MORNING HOURS. THE PASSAGE OF THE COLD
FRONT WILL BRING A SHIFT TO NORTHWEST WINDS WHICH WILL INCREASE WITH
GUSTS PUSHING 35-40 MPH FROM LATE MORNING THROUGH THE AFTERNOON
LEADING TO BLOWING SNOW. HIGHS SHOULD BE RIGHT AROUND 30...THOUGH
THERE COULD BE A SLIGHT DECREASE IN TEMPS IN THE AFTERNOON WITH SOME
COOL ADVECTION BUT CLEARING SKIES AND SUNSHINE MAY OFFSET THIS. LOWS
TUESDAY NIGHT SHOULD FALL INTO THE MID TEENS WITH WINDS DIMINISHING
AND TURNING SOUTHWEST.
WEDNESDAY THROUGH FRIDAY...THE UPPER TROUGH CARVED OUT BY THE SERIES
OF CLIPPERS WILL SWING TO THE EAST AND OFF THE NEW ENGLAND COAST
WEDNESDAY ALLOWING FOR BROAD UPPER RIDGING TO SPREAD ACROSS THE
U.S. THIS WILL BRING A PUSH OF MID LEVEL WARM ADVECTION TO THE
REGION WEDNESDAY INTO THURSDAY WITH H85 TEMPS WARMING TO AROUND +6C
OR SO AND H92 TEMPS WARMING JUST ABOVE 0C. THIS WILL ALLOW FOR
SURFACE WARMING AS WELL BUT SNOW COVER WILL BE ONE LIMITING FACTOR.
TEMPS WEDNESDAY WILL BE TRICKY BECAUSE ASIDE FROM SOME MID LEVEL WAA
CLOUDS EARLY THERE WILL LIKELY BE AT LEAST SOME SUN AS WELL AS A
STRONG SOUTHWEST WIND. BOTH OF THESE POINT TOWARD WARMER HIGHS GIVEN
THAT THE LOWER ATMOSPHERE WILL STILL BE RELATIVELY DRY. THIS SHOULD
ALLOW MOST AREAS TO WARM TO OR JUST ABOVE FREEZING. BY THURSDAY...AN
UPPER TROUGH WILL BE WORKING INTO THE WESTERN U.S. WITH THE UPPER
FLOW SPLITTING INTO TWO STREAMS AS THE TROUGH DIGS SOUTH AND CUTS
OFF OVER OR JUST OFF THE CALIFORNIA COAST. HEIGHT FALLS AHEAD OF
THIS TROUGHING WILL LEAD TO SURFACE LOW PRESSURE DEVELOPMENT ACROSS
THE CENTRAL/SOUTHERN ROCKIES WITH AN INVERTED TROUGH AXIS EXTENDING
NORTHEAST ACROSS THE LOCAL AREA. DEEP LAYER MOISTURE WILL BE
INCREASING THURSDAY LEADING TO PRECIP CHANCES...ESPECIALLY LATER IN
THE DAY WITH LOW LEVEL MOIST ADVECTION ACTING ON THE SNOW PACK TO
LIKELY GENERATE FOG. THIS WILL PROBABLY KEEP TEMPS IN THE MID TO
UPPER 30S. PRECIP MAY END UP BEING MORE DRIZZLE THAN FALLING PRECIP
THROUGH THE DAY AND POSSIBLY THE EVENING/OVERNIGHT. THE UPPER FLOW
LOOKS TO REMAIN SPLIT WITH NORTHERN STREAM ENERGY KICKING THE
SURFACE LOW NORTHEAST RIGHT ACROSS THE AREA THURSDAY NIGHT AND
FRIDAY MORNING. THIS WILL ALSO BRING A COLD FRONT THOUGH THE AREA
EARLY FRIDAY. ANY RAIN WILL LIKELY TURN TO A MIX OR ALL SNOW FRIDAY
MORNING. OVERALL PRECIP AMOUNTS LOOK LIGHT WITH WEAK OR DISJOINTED
FORCING. HIGHS FRIDAY WILL LIKELY BE EARLY THEN FALL THROUGH THE
DAY.
SATURDAY THROUGH MONDAY...THIS PERIOD BEARS WATCHING AS ENERGY FROM
THE SOUTHERN STREAM CUTOFF UPPER LOW IS EXPECTED TO KICK NORTHEAST
THIS WEEKEND AS A REINFORCING UPPER TROUGH MOVES SOUTHEAST INTO THE
NORTHERN PLAINS. THIS WILL LIKELY SEND A SURFACE LOW AND/OR INVERTED
TROUGH NORTHEAST WITH RECENT GUIDANCE BRINGING IT SOUTHEAST OF THE
AREA. RIGHT NOW THE FAVORED TIME FOR THE SYSTEM TO BRING PRECIP TO
THE AREA WOULD BE LATER SATURDAY INTO SUNDAY. GIVEN THE PRECEDING
SHIFT IN THE UPPER FLOW TO A MORE ZONAL PATTERN AHEAD OF THE
TROUGHED FLOW...THERMAL FIELDS WILL BE MORE CRITICAL IN THAT THEY
WILL LIKELY BE WARM ENOUGH FOR A RANGE OF PRECIP TYPES TO OCCUR
DEPENDING ON WHERE THE LOW TRACKS. OVERALL SYSTEM STRENGTH AND
MOISTURE FEED SUPPORT HIGHER END PRECIP AMOUNTS WITH AFFECTED AREAS
DEPENDING ON THE TRACK. STILL VERY EARLY TO HAVE MUCH CONFIDENCE IN
DETAILS GIVEN THE EVOLUTION OF UPPER FLOW THAT NEEDS TO TAKE PLACE
IN THE MEANTIME BUT THERE LOOKS TO BE A GOOD CHANCE FOR A SYSTEM TO
BE AFFECTING THE REGION.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* SNOW W/ IFR/LIFR VIS IMPACTING THE TERMINALS...THROUGH 01Z-
0130Z.
* MVFR CEILINGS TONIGHT.
* ANOTHER ROUND OF SNOW EXPECTED BETWEEN 12 AND 16 UTC...WITH LOW
VIS DOWN AROUND 1SM LIKELY.
* STRONG WEST NORTHWEST WINDS DEVELOPING AFTER 16 UTC ON TUESDAY.
RODRIGUEZ
//DISCUSSION...UPDATED 00Z...
WITH THE DEPARTURE OF THIS PAST AFTERNOONS SNOW...A SECOND AREA OF
LIGHT TO MODERATE SNOW HAS DEVELOPED AND CONTINUES TO MOVE OVER
ALL THE TERMINALS AT THIS TIME. ALTHOUGH...THIS SNOW WILL END FROM
WEST TO EAST STARTING THIS UPCOMING HOUR THROUGH THE 2Z TIME
FRAME. IFR VIS WITH A BRIEF PERIOD OF LIFR VIS WILL BE
POSSIBLE...BEFORE CONDITIONS RAPIDLY IMPROVE. MVFR CEILINGS
PREVAIL THIS HOUR ACROSS THE TAF SITES AND EXPECT THESE LOWER
CEILINGS TO HOLD IN PLACE OVERNIGHT. CONTINUE TO MONITOR A SIMILAR
SYSTEM WHICH WILL QUICKLY ARRIVE EARLY TUESDAY MORNING...PROVIDING
A PERIOD OF LIGHT TO MODERATE SNOW THROUGH MID MORNING. SIMILAR
CEILING/VIS TRENDS ARE EXPECTED...WITH CEILINGS HOLDING AT MVFR
AND VIS DROPPING TO AROUND 1 MILE AT TIMES. WEST NORTHWEST WINDS
WILL PICK UP ON THE BACKSIDE OF THIS SYSTEM WITH GUSTS AROUND 30KT
POSSIBLE INTO THE AFTERNOON.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE WITH SNOW/VIS/CIG TRENDS IN THE NEAR TERM.
* HIGH CONFIDENCE WITH CEILINGS/TRENDS TONIGHT.
* MEDIUM-HIGH CONFIDENCE IN SNOW TUESDAY MORNING.
* MEDIUM CONFIDENCE WITH WIND SPEED/GUSTS TUESDAY.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN W/ FOG.
FRIDAY...CHANCE OF RAIN OR SNOW BECOMING ALL SNOW BY THE
AFTERNOON.
SATURDAY...CHANCE OF SNOW.
SUNDAY...CHANCE OF SNOW.
RODRIGUEZ
&&
.MARINE...
204 PM CST
A SERIES OF DISTURBANCES WILL LEAD TO SEVERAL WIND SHIFTS THROUGH
THE REMAINDER OF THE WEEK...AS WELL AS A BRIEF PERIOD OF GALES WHICH
IS EXPECTED TUESDAY. TODAY HIGH PRESSURE IS STARTING TO DRIFT EAST
OF LAKE MICHIGAN WITH SOUTHWEST FLOW INCREASING IN ADVANCE OF AN
APPROACHING COLD FRONT. THIS FIRST FRONT WILL MOVE ACROSS LAKE
MICHIGAN WITH WINDS VEERING TO WESTERLY OVERNIGHT. A SECOND FRONT
WILL BE RIGHT ON ITS HEELS THOUGH...AND WILL PUSH ACROSS LAKE
MICHIGAN TUESDAY AFTERNOON WITH WINDS SHIFTING NORTHWESTERLY. A
BETTER SURGE OF COLD AIR WILL BE ASSOCIATED WITH THIS SECOND
FRONT...AS WELL AS A TIGHTER PRESSURE GRADIENT WITH A MODERATE RIDGE
BUILDING ALONG THE MISSISSIPPI VALLEY...LEADING TO A PERIOD OF WEST
TO NORTHWEST GALES...PARTICULARLY ACROSS THE SOUTH HALF OF THE LAKE.
GALES WILL DIMINISH TUESDAY NIGHT AND WINDS WILL BEGIN TO BACK TO
THE SOUTHWEST WEDNESDAY AS THE RIDGE PROGRESSES EAST ACROSS LAKE
MICHIGAN. SOUTHWEST WINDS FRESHEN UP AGAIN WEDNESDAY NIGHT AS YET
ANOTHER FRONT IS POISED TO SWEEP ACROSS THE LAKE EARLY THURSDAY.
MODERATE NORTHERLY FLOW IS EXPECTED FRIDAY BEHIND THE FRONT AS
ANOTHER LOW PRESSURE SKIRTS TO THE EAST...JUST SOUTH OF THE
GREAT LAKES.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ744-LMZ745...MIDNIGHT TUESDAY TO 9 AM
TUESDAY.
GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM TUESDAY TO 9 PM TUESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...MIDNIGHT
TUESDAY TO MIDNIGHT WEDNESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
1000 AM MST SUN DEC 15 2013
.UPDATE...
ISSUED AT 740 AM MST SUN DEC 15 2013
COMBINATION OF 850 TEMPERATURES...RUC AND HRRR SFC TEMPS SUPPORT
RAISING HIGH TEMPERATURES TODAY INTO THE MID 50S WITH LOW
60S...WARMEST READINGS ACROSS THE EAST/SOUTHEAST. WEST/NORTHWEST
WINDS WILL BECOME BREEZY PERHAPS LATE MORNING THROUGH THE REST OF
THE DAY. CLOUDINESS CURRENTLY OVER THE AREA EXPECTED TO MOVE OUT
OF THE AREA WITHIN THE NEXT FEW HOURS LEAVING SUNNY/MOSTLY SUNNY
CONDITIONS FOR THE REST OF THE DAY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 154 AM MST SUN DEC 15 2013
DRY AND MILD CONDITIONS WILL REMAIN IN PLACE ACROSS THE FORECAST
AREA THROUGH THE SHORT TERM PERIOD.
MODELS KEEP THE UPPER RIDGE OVER THE WEST COAST THROUGH MONDAY
WITH NORTHWEST FLOW ALOFT ACROSS THE CENTRAL HIGH PLAINS REGION.
DURING THIS TIME...A SURFACE TROUGH MOVES ACROSS THE NORTHERN
PLAINS TOWARDS THE GREAT LAKES REGION WITH THE TAIL END OF THE
TROUGH EXTENDING BACK INTO THE CENTRAL AND SOUTHERN HIGH PLAINS
REGION. THIS WILL KEEP GENERALLY WEST TO NORTHWEST SURFACE FLOW IN
PLACE ACROSS THE FORECAST AREA WITH DOWNSLOPING WINDS AND WARM AND
DRY CONDITIONS.
SURFACE HIGH PRESSURE MOVES INTO THE REGION AS THE TROUGH EXITS
WITH ANOTHER SURFACE TROUGH DEEPENING ALONG THE FRONT RANGE BY
TUESDAY NIGHT AS THE UPPER FLOW ACROSS THE UNITED STATES FLATTENS
WITH THE APPROACH OF THE NEXT UPPER TROUGH.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 154 AM MST
SUN DEC 15 2013
FOR WEDNESDAY THROUGH SATURDAY MAIN INTEREST WILL CONTINUE TO BE THE
ARCTIC FRONTAL PASSAGE THURSDAY WITH CHANCES FOR SNOW THE FOLLOWING
NIGHT. MODELS HAVE COME INTO BETTER AGREEMENT WITH THE UPPER LEVEL
WEATHER PATTERN FOR THE END OF THE WEEK...AND HAVE SPED UP THE
FRONTAL PASSAGE TO THE AFTERNOON HOURS. MODELS CONTINUE TO SHOW A
SPLIT 500MB JET BEHIND THE FRONT. AS A RESULT THE BEST SHOT FOR
SNOWFALL WILL BE THURSDAY EVENING OVER THE NORTHWEST WHERE MID LEVEL
FRONTOGENESIS WILL DEVELOP. FRIDAY THE NORTHERN HALF OF THE 500MB
JET WILL MOVE AN UPPER LEVEL SHORT WAVE TROUGH AXIS OVER THE AREA
WITH SUBSIDENCE MOVING IN BEHIND THE TROUGH AXIS. MODEL SOUNDINGS
INDICATE THE ENVIRONMENT SHOULD SATURATE FAIRLY QUICKLY BEHIND THE
FRONT...ALTHOUGH THERE MAY STILL BE A BRIEF PERIOD OF FREEZING
DRIZZLE.
HIGH TEMPERATURES FOR PERIOD WILL BE NEARLY 20 DEGREES ABOVE NORMAL
WEDNESDAY THEN FALL TO 10-20 DEGREES BELOW NORMAL BY FRIDAY AND
SATURDAY. LOWS WILL BE 10 DEGREES ABOVE NORMAL WEDNESDAY NIGHT
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1000 AM MST SUN DEC 15 2013
FOR KGLD AND KMCK VFR CONDITIONS EXPECTED THROUGH THE PERIOD.
WEST/NORTHWEST WINDS 15-20KTS WITH HIGHER GUSTS AT BOTH TERMINALS
EXPECTED THROUGH 23Z-00Z THEN BECOMING W/NW AT 10KTS THROUGH THE
REST OF THE TAF PERIOD. SOME MID AND/OR HIGH LEVEL CLOUDS EXPECTED
TO MOVE THROUGH FROM THE NORTHWEST...MAINLY LATE TONIGHT INTO
MONDAY MORNING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...LOCKHART
LONG TERM...JTL
AVIATION...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
740 AM MST SUN DEC 15 2013
.UPDATE...
ISSUED AT 740 AM MST SUN DEC 15 2013
COMBINATION OF 850 TEMPERATURES...RUC AND HRRR SFC TEMPS SUPPORT
RAISING HIGH TEMPERATURES TODAY INTO THE MID 50S WITH LOW
60S...WARMEST READINGS ACROSS THE EAST/SOUTHEAST. WEST/NORTHWEST
WINDS WILL BECOME BREEZY PERHAPS LATE MORNING THROUGH THE REST OF
THE DAY. CLOUDINESS CURRENTLY OVER THE AREA EXPECTED TO MOVE OUT
OF THE AREA WITHIN THE NEXT FEW HOURS LEAVING SUNNY/MOSTLY SUNNY
CONDITIONS FOR THE REST OF THE DAY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 154 AM MST SUN DEC 15 2013
DRY AND MILD CONDITIONS WILL REMAIN IN PLACE ACROSS THE FORECAST
AREA THROUGH THE SHORT TERM PERIOD.
MODELS KEEP THE UPPER RIDGE OVER THE WEST COAST THROUGH MONDAY
WITH NORTHWEST FLOW ALOFT ACROSS THE CENTRAL HIGH PLAINS REGION.
DURING THIS TIME...A SURFACE TROUGH MOVES ACROSS THE NORTHERN
PLAINS TOWARDS THE GREAT LAKES REGION WITH THE TAIL END OF THE
TROUGH EXTENDING BACK INTO THE CENTRAL AND SOUTHERN HIGH PLAINS
REGION. THIS WILL KEEP GENERALLY WEST TO NORTHWEST SURFACE FLOW IN
PLACE ACROSS THE FORECAST AREA WITH DOWNSLOPING WINDS AND WARM AND
DRY CONDITIONS.
SURFACE HIGH PRESSURE MOVES INTO THE REGION AS THE TROUGH EXITS
WITH ANOTHER SURFACE TROUGH DEEPENING ALONG THE FRONT RANGE BY
TUESDAY NIGHT AS THE UPPER FLOW ACROSS THE UNITED STATES FLATTENS
WITH THE APPROACH OF THE NEXT UPPER TROUGH.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 154 AM MST
SUN DEC 15 2013
FOR WEDNESDAY THROUGH SATURDAY MAIN INTEREST WILL CONTINUE TO BE THE
ARCTIC FRONTAL PASSAGE THURSDAY WITH CHANCES FOR SNOW THE FOLLOWING
NIGHT. MODELS HAVE COME INTO BETTER AGREEMENT WITH THE UPPER LEVEL
WEATHER PATTERN FOR THE END OF THE WEEK...AND HAVE SPED UP THE
FRONTAL PASSAGE TO THE AFTERNOON HOURS. MODELS CONTINUE TO SHOW A
SPLIT 500MB JET BEHIND THE FRONT. AS A RESULT THE BEST SHOT FOR
SNOWFALL WILL BE THURSDAY EVENING OVER THE NORTHWEST WHERE MID LEVEL
FRONTOGENESIS WILL DEVELOP. FRIDAY THE NORTHERN HALF OF THE 500MB
JET WILL MOVE AN UPPER LEVEL SHORT WAVE TROUGH AXIS OVER THE AREA
WITH SUBSIDENCE MOVING IN BEHIND THE TROUGH AXIS. MODEL SOUNDINGS
INDICATE THE ENVIRONMENT SHOULD SATURATE FAIRLY QUICKLY BEHIND THE
FRONT...ALTHOUGH THERE MAY STILL BE A BRIEF PERIOD OF FREEZING
DRIZZLE.
HIGH TEMPERATURES FOR PERIOD WILL BE NEARLY 20 DEGREES ABOVE NORMAL
WEDNESDAY THEN FALL TO 10-20 DEGREES BELOW NORMAL BY FRIDAY AND
SATURDAY. LOWS WILL BE 10 DEGREES ABOVE NORMAL WEDNESDAY NIGHT
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 405 AM MST SUN DEC 15 2013
CONDITIONS AT MCK AND GLD WILL REMAIN VFR THROUGH THE TAF PERIOD
WITH SCATTERED MID TO HIGH LEVEL CLOUDS EXPECTED TO MOVE ACROSS
THE SITES THROUGH EARLY AFTERNOON. LIGHT WEST WINDS WILL TURN
NORTHWEST AND BECOME GUSTY BY 17Z WITH A SURFACE TROUGH IN PLACE
ACROSS THE CENTRAL HIGH PLAINS. WINDS WILL TURN WESTERLY AND
BECOME LIGHT AGAIN AFTER 23Z AS SKIES REMAIN MOSTLY CLEAR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...LOCKHART
LONG TERM...JTL
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
959 PM EST Mon Dec 16 2013
...Forecast Update...
Issued at 958 PM EST Mon Dec 16 2013
Made a few updates to the overnight forecast. The clipper system to
our north continues to track across the Great Lakes, with clouds on
the increase across the forecast area. A few radar returns across
our northern CWA are tracking east-southeast and may contain a few
flurries. So, have added this to the forecast for a few hours,
tracking from southeast IN into the northern Blue Grass region of
KY. Otherwise, the surface front, as noted in the short-term
forecast discussion, will settle just south of the Ohio River
overnight. Low-level moisture below about 2Kft will accompany this
boundary. All signs point to low clouds building in around or
shortly after 4 AM EST and lingering through daybreak, coincident
with the front. Not expecting precip with this boundary given the
very shallow/thin moisture, but cannot rule out some very light,
patchy drizzle. The rest of the forecast remains on track.
.SHORT TERM (Now through Tuesday Night)...
Issued at 257 PM EST Mon Dec 16 2013
A tight temperature gradient, augmented by differences in snowpack,
currently lies across southern Indiana. At 2 pm, temperatures ranged
from 45 at Louisville to 24 degrees at Indianapolis. Low clouds and
light fog will continue right along a line from Dubois through
Jefferson County, Indiana.
Farther south, clear skies and mild temperatures will continue
through this evening, as light southwest winds continue.
The synoptic pattern across the CONUS features a broad longwave
500mb trough over the Great Lakes. Two weak shortwaves will move
across Indiana over the next couple of days. The first will push a
weak cold front south of the Ohio River this evening and overnight.
No precipitation is expected with no mid-level moisture. However,
winds will shift to the west overnight, and temperatures will lower
a few degrees from our lows earlier this morning.
The second front will move across during the day Tuesday. A tight
pressure gradient will develop during the afternoon as high
pressure builds south across Kansas. West winds will pick up
during the afternoon and peak around 15 mph with some gusts over
25 mph.
Clouds will increase by late this evening as cooler air filters
in. Expect that cloudy skies will continue through the morning
hours Tuesday, especially north of Interstate 64. Lows tonight
will range from the upper 20s north to the lower 30s towards
Tennessee.
Tuesday will remain cooler than earlier this afternoon, even over
our southern counties, with highs ranging from the mid 30s to the
mid 40s. High pressure will build east over Tennessee Tuesday
night. Expect mostly clear skies and lows from the upper 20s to
the lower 30s.
.LONG TERM (Wednesday through Monday)...
Issued at 250 PM EST Mon Dec 16 2013
A couple of noticeable pattern changes are on the way for the
extended forecast. The first will come as the persistent upper
trough over our region flattens out and allows warmer temperatures
into the region. High temperatures have been below normal at SDF
since the snowfall of 12/6, and they should flip back above by
Wednesday with highs going up into the 60s possibly by Friday. This
warm air will come from a southerly flow that becomes established as
high pressure to our southwest makes it way east of the area
Thursday.
The next pattern change will come from an upper low currently along
the Alaskan coast. A piece of this energy will drop to the southern
California coast and stall for a bit. Despite apparent unity among
the deterministic models on this forecast, ensemble spreads still
show a bit of uncertainty. Still the rough location of this feature
will tilt the flow aloft over us to southwesterly, which should
increase our moisture. Combined with a cold front forecast to move
in Friday with a northern stream trough will mean a good shot at
rain.
That front still looks to stall somewhere in the area for the
weekend and with continued southwesterly flow will mean good rain
chances likely through the weekend. As with the agreement on what
the upper low will do Friday, the GFS/GEM/Euro also are in
general agreement with that low opening up and moving into the
southern Plains Sunday. In response a surface low should develop
along the stalled frontal boundary. As with any system this far out,
there will be timing/location differences for several model runs to
come on where this surface low tracks/how deep it gets. Thus we have
a low confidence forecast in temps and potentially precip type over
our northern forecast area.
Will keep in good rain chances through the weekend, and then leave
in lesser chances for Monday, with the upper trough passage.
Rainfall totals from Thursday night through Sunday night with this
package will range from 2.5-3.5 inches across the region. Depending
on how quick this rain comes at any one time, we may see some water
issues, and will keep that wording in our HWO. In addition, should
the deepening low track close to our area, we will have to watch for
severe weather potential as well. Stay tuned.
&&
.HYDROLOGY...
Issued at 300 PM EST Fri Dec 16 2013
A winter storm will move across the Ohio Valley this weekend. A cold
front will stall and a series low pressure systems will move along
the front. Several waves of precipitation will begin Thursday night
and continue through Sunday. In southern Indiana and Kentucky these
systems are forecast to bring a large amount of rain. This area is
recovering from heavy rain and snowmelt from the previous storm so
the rivers and streams will respond faster and rise higher than
during the previous storm. More specific forecasts will be released
as the event comes clearer.
&&
.AVIATION (00Z TAF Update)...
Updated at 630 PM EST Mon Dec 16 2013
All sites are reporting VFR conditions, which should hold a little
longer this evening before clouds build back across the region, as a
clipper system tracks southeast through the Great Lakes tonight.
Ceilings will be a low confidence forecast for SDF and LEX. Guidance
has backed off a bit on MVFR cigs overnight and upstream obs are no
help either, with the low cigs across IL occurring over the snow
pack. However, given the latest RAP analysis and low-level moisture
still depicted in the soundings and time heights, will go with MVFR
ceilings at SDF and LEX overnight and into mid morning Tuesday
before improving. The RAP indicates IFR conditions and if the very
moist low-level profile pans out, this could be correct. Not
confident enough to go that low just yet. Confidence is lower that
ceilings will drop to MVFR at BWG, thus will keep conditions VFR
through the overnight period. Expect light winds tonight but they
will pick up out of the west Tuesday, increasing to around 10-15
knots with a few gusts of 20-25 knots during the afternoon.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........MJP
Short Term.....JSD
Long Term......RJS
Hydrology......CMC
Aviation.......MJP
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
633 PM EST Mon Dec 16 2013
...Updated Aviation Discussion...
.SHORT TERM (Now through Tuesday Night)...
Issued at 257 PM EST Mon Dec 16 2013
A tight temperature gradient, augmented by differences in snowpack,
currently lies across southern Indiana. At 2 pm, temperatures ranged
from 45 at Louisville to 24 degrees at Indianapolis. Low clouds and
light fog will continue right along a line from Dubois through
Jefferson County, Indiana.
Farther south, clear skies and mild temperatures will continue
through this evening, as light southwest winds continue.
The synoptic pattern across the CONUS features a broad longwave
500mb trough over the Great Lakes. Two weak shortwaves will move
across Indiana over the next couple of days. The first will push a
weak cold front south of the Ohio River this evening and overnight.
No precipitation is expected with no mid-level moisture. However,
winds will shift to the west overnight, and temperatures will lower
a few degrees from our lows earlier this morning.
The second front will move across during the day Tuesday. A tight
pressure gradient will develop during the afternoon as high
pressure builds south across Kansas. West winds will pick up
during the afternoon and peak around 15 mph with some gusts over
25 mph.
Clouds will increase by late this evening as cooler air filters
in. Expect that cloudy skies will continue through the morning
hours Tuesday, especially north of Interstate 64. Lows tonight
will range from the upper 20s north to the lower 30s towards
Tennessee.
Tuesday will remain cooler than earlier this afternoon, even over
our southern counties, with highs ranging from the mid 30s to the
mid 40s. High pressure will build east over Tennessee Tuesday
night. Expect mostly clear skies and lows from the upper 20s to
the lower 30s.
.LONG TERM (Wednesday through Monday)...
Issued at 250 PM EST Mon Dec 16 2013
A couple of noticeable pattern changes are on the way for the
extended forecast. The first will come as the persistent upper
trough over our region flattens out and allows warmer temperatures
into the region. High temperatures have been below normal at SDF
since the snowfall of 12/6, and they should flip back above by
Wednesday with highs going up into the 60s possibly by Friday. This
warm air will come from a southerly flow that becomes established as
high pressure to our southwest makes it way east of the area
Thursday.
The next pattern change will come from an upper low currently along
the Alaskan coast. A piece of this energy will drop to the southern
California coast and stall for a bit. Despite apparent unity among
the deterministic models on this forecast, ensemble spreads still
show a bit of uncertainty. Still the rough location of this feature
will tilt the flow aloft over us to southwesterly, which should
increase our moisture. Combined with a cold front forecast to move
in Friday with a northern stream trough will mean a good shot at
rain.
That front still looks to stall somewhere in the area for the
weekend and with continued southwesterly flow will mean good rain
chances likely through the weekend. As with the agreement on what
the upper low will do Friday, the GFS/GEM/Euro also are in
general agreement with that low opening up and moving into the
southern Plains Sunday. In response a surface low should develop
along the stalled frontal boundary. As with any system this far out,
there will be timing/location differences for several model runs to
come on where this surface low tracks/how deep it gets. Thus we have
a low confidence forecast in temps and potentially precip type over
our northern forecast area.
Will keep in good rain chances through the weekend, and then leave
in lesser chances for Monday, with the upper trough passage.
Rainfall totals from Thursday night through Sunday night with this
package will range from 2.5-3.5 inches across the region. Depending
on how quick this rain comes at any one time, we may see some water
issues, and will keep that wording in our HWO. In addition, should
the deepening low track close to our area, we will have to watch for
severe weather potential as well. Stay tuned.
&&
.HYDROLOGY...
Issued at 300 PM EDT Fri Dec 16 2013
A winter storm will move across the Ohio Valley this weekend. A cold
front will stall and a series low pressure systems will move along
the front. Several waves of precipitation will begin Thursday night
and continue through Sunday. In southern Indiana and Kentucky these
systems are forecast to bring a large amount of rain. This area is
recovering from heavy rain and snowmelt from the previous storm so
the rivers and streams will respond faster and rise higher than
during the previous storm. More specific forecasts will be released
as the event comes clearer.
&&
.AVIATION (00Z TAF Update)...
Updated at 630 PM EST Mon Dec 16 2013
All sites are reporting VFR conditions, which should hold a little
longer this evening before clouds build back across the region, as a
clipper system tracks southeast through the Great Lakes tonight.
Ceilings will be a low confidence forecast for SDF and LEX. Guidance
has backed off a bit on MVFR cigs overnight and upstream obs are no
help either, with the low cigs across IL occurring over the snow
pack. However, given the latest RAP analysis and low-level moisture
still depicted in the soundings and time heights, will go with MVFR
ceilings at SDF and LEX overnight and into mid morning Tuesday
before improving. The RAP indicates IFR conditions and if the very
moist low-level profile pans out, this could be correct. Not
confident enough to go that low just yet. Confidence is lower that
ceilings will drop to MVFR at BWG, thus will keep conditions VFR
through the overnight period. Expect light winds tonight but they
will pick up out of the west Tuesday, increasing to around 10-15
knots with a few gusts of 20-25 knots during the afternoon.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Short Term........JSD
Long Term.........RJS
Hydrology.........CMC
Aviation..........MJP
AREA FORECAST DISCUSSION
NWS PADUCAH KY
215 PM CST Sun Dec 15 2013
.SHORT TERM...(This Evening through Tuesday Night)
ISSUED AT 213 PM CST SUN DEC 15 2013
The short term forecast will continue to be a sky and temperature
challenge, as no measureable precipitation is forecast with
northwest flow aloft continuing.
Plenty of remnant low level moisture has resulted in a prolonged
period of cloudy skies early today. However, by mid morning,
progress was being made in clearing skies in parts of southeast MO.
The RAP model seemed to be doing the best with regards to the low
level moisture departing that area. It indicates that the clearing
will continue across southeast MO and maybe a bit further east into
southwest IL/KY However, upstream cloudiness from disturbances aloft
will likely keep most of southern IL, southwest IN and a good chunk
of western KY in the clouds through tonight into Monday.
Weak warm air advection will start up in southeast MO later today
and into tonight. As this weak warm advection develops over top a
cold moist snow covered ground, we could be looking at fog
potential, as noted by the previous shift. Fog will be most
prevalent in areas where the clouds have cleared and stay clear.
Therefore, we expect the greatest fog potential in southeast MO. It
will be tricky though because there is quite a bit of low level
moisture upstream yet to travel down this way so pinpointing what
areas might stay partly cloudy vs cloudy will be difficult,
especially when mid clouds are expected later tonight as well.
Interestingly enough, the 12Z SREF indicates the best chance for fog
development, especially after 06Z tonight, in SEMO/far southwest IL.
However, numerical guidance is not as hot on the idea. Will opt for
patchy fog wording in SEMO for now and let the evening shift adjust
as need be.
Although no precipitation is forecast for tonight, weak disturbances
in the flow are going to bring some mid level moisture. Northern
neighboring WFOs have flurries/light snow forecast for tonight.
Looking at soundings/mid level moisture plots in our area, there does
appear to be enough moisture aloft (especially around 06Z)to produce
snowflakes but the atmosphere is very dry below 750mb. But in our
extreme northern counties, the 18Z NAM indicates there just might be
enough moisture and we could wet bulb enough to produce a few
flurries up north of the I-64 corridor but most of the activity
should stay to our north, where the better moisture will be.
Monday through Tuesday, below normal temperatures will persist as
the region remains in northwest flow aloft on the back side of a
longwave trough over the east. Minor disturbances traveling through
this NW flow will likely bring us intermittent clouds but no
precipitation is currently forecast...with the cloudiest areas
being southern IL, southwest IN and parts of west KY. Finally, we
start to get rid of this low level moisture Monday night into
Tuesday across a good part of the area. We will also see robust warm
air advection take place Tuesday night, which will start our big
warm up.
.LONG TERM...(Wednesday through Sunday)
ISSUED AT 213 PM CST SUN DEC 15 2013
Will continue the forecast for an active weather regime late this
week possibly extending into the weekend.
Surface high pressure`s dominance on our FA will quickly fade as the
high moves east toward the south Atlantic Coast by Wednesday
evening. This will set the stage for southerly winds and a
pronounced warm up Wednesday with the FA remaining in the warm
sector until a cold front moves across the FA Friday. Both the ECMWF
and GFS now bring this front through the FA Friday with the ECMWF
now even a bit faster than the GFS. Will maintain small POPS across
the west/NW part of the FA for Thursday and increase POPS slightly
for Thursday night and Friday given the fairly consistent signal
with the synoptic pattern through Friday. Will also keep a chance of
thunderstorms for Thu night and Fri with K indices consistently AOA
30 for the last several model runs.
Confidence with the post frontal part of the forecast remains more
uncertain given major model changes with the GFS in particular. This
is due to forecasting the movement of the southwest U.S. upper
low/trough which is much slower with the latest GFS run and
therefore the significant change/lesser precip chances for the
weekend as a result of the southeast progression of the surface cold
front and subsequent post frontal drying. Will tend to lean more
toward the ECMWF position of maintaining... including with the 12Z
model run...ample moisture across our FA given its NE progression of
the upper low.
Precip type will once again be borderline with the often
generalization of the N part of the FA having the best chance for
wintry precip and areas near the MO/AR and KY/TN border having a
greater likelihood of rain as supported by a blend of several
thickness parameters. This is particularly valid of the late weekend
precip ahead of the upper low...assuming this even materializes
given the aforementioned model differences.
Warm air advection will occur Wed-Fri until the cold front moves
through the FA Friday. The trend has been even warmer temps for
Thursday which is now forecast to be as warm as Friday with the
exception of the southeast/Pennyrile area where a later passage of
the cold front should result in Friday temps AOA 60. Back to more
typical temps thereafter.
&&
.AVIATION...
ISSUED AT 213 PM CST SUN DEC 15 2013
Mid afternoon satellite imagery and surface observations indicated
clearing pushing steadily east and nearing the Mississippi River.
MVFR cigs at CGI and KPAH should become scattered through the late
afternoon. KEVV and KOWB will likely remain under MVFR cigs until
this evening when clouds should become scattered to broken at KEVV
and KOWB. A band of moisture/broken ceilings about 6-9K feet is
projected southeast across the TAF sites tonight with a few flurries
possible around KEVV and KOWB. Winds will increasingly become
southwest at 5 to 10 knots with lighter winds at KEVV and KOWB
tonight. Will have to watch for potential fog tonight there.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
CW/RS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
415 PM EST SUN DEC 15 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL CONTINUE MOVING EAST OVERNIGHT THROUGH
THE SOUTHERN MARITIMES INTO THE OPEN ATLANTIC. HIGH PRESSURE WILL
APPROACH ON MONDAY AND CREST OVER THE REGION MONDAY NIGHT. LOW
PRESSURE WILL FORM NEAR SOUTHERN NEW ENGLAND ON TUESDAY. THIS LOW
WILL TRACK SOUTH OF THE GULF OF MAINE TUESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
410 PM UPDATE: WITH SIG ACCUMULATING SNFL MOVING OUT OF PORTIONS
OF DOWNEAST AND EAST CENTRAL ME...WE HAVE BEGUN CANX WNTR STRM
WRNGS AS PER THE PREV NEAR TERM DISC. REST OF NEAR TERM FCST
ELEMENTS REMAIN THE SAME.
ORGNL DISC: LATEST HOURLY HRRR MODEL OUTPUT SHOWS HEAVIER SN BAND
ORGANIZATION BREAKING DOWN OVR ERN PTNS OF THE FA AND THEN MOVG
INTO NEW BRUNSWICK OVR THE NEXT FEW HRS...LEAVING LGT SNFL MAINLY
OVR THE N HLF OF THE FA INTO THE OVRNGT. WILL HOLD ON TO WNTR STRM
WRNGS FOR NOW...BUT ENVISION THEM BEING DROPPED FROM SW TO NE
BEGINNING WITHIN THE NEXT FEW HRS...WITH EVEN NRN ZONES BEING
DROPPED...SINCE SN RATES AND ACCUMULATIONS WILL BE TO LOW TO
SUSTAIN IMPACT...AND NEARLY ALL...IF NOT ALL OF THE CURRENT WRNGS
HAVE ALREADY BEEN VERIFIED WITH SNFL THAT HAS FALLEN TO THIS
POINT.
OTHERWISE...SFC TEMPS WILL BE FALLING W AND DOWNEAST INTO THE EVE
AND SLOWLY RISING ACROSS THE N AND E DUE TO DIFFERENTIAL THERMAL`
ADVCN ACROSS THE FA. TEMPS MAY COOL OVR THE NE BY DAYBREAK...BUT
NOT BY MUCH AS A LLVL THERMAL RIDGE HANGS ON AND LLVL COLD ADVCN
BEGINS TO PUNCH EWRD ACROSS WRN AND DOWNEAST AREAS. WINDS SHOULD
DIMINISH THROUGH THE EVENING AND OVRNGT AS THE LLVL PRES GRAD
SLACKENS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
A TROUGH OF LOWER PRESSURE EXTENDS ACROSS NORTHERN MAINE AND HIGH
PRESSURE RIDGE BUILDS INTO WESTERN MAINE AT THE START OF THE
PERIOD. A FEW LINGERING SNOW SHOWERS EARLY...THEN CLEARING. THE
HIGH PRESSURE WILL MOVE EAST OF THE AREA LATE TUESDAY AS THE NEXT
LOW MOVES INTO THE GULF OF MAINE. THE MODELS ARE AT A BIT OF
DISAGREEMENT ON THE POSITION AND MOVEMENT OF THE LOW AS IT EXITS
INTO THE NORTH ATLANTIC. THE ECMWF...NAM...GEM KEEP THE LOW IN THE
NORTHERN PORTIONS OF THE GULF OF MAINE. WITH THE ECMWF AND GEM THE
FARTHEST NORTH. THE GFS MOVES THE LOW OFF THE COAST SOUTH OF CAPE
COD AND MOVES IT EAST WELL SOUTH OF NOVA SCOTIA. A CONSENSUS
FORECAST OF THE ECMWF...NAM...AND GEM BRINGS THE HIGHEST POPS AND
QPF INTO THE SOUTHEASTERN AND EASTERN PORTIONS OF THE AREA. THE
CONSENSUS BLEND FOR QPF GIVES ABOUT THREE TENTHS OF AN INCH IN THE
HOULTON AREA...ABOUT SIX TENTHS OF AN INCH INTO THE ELSWORTH AREA.
THE BULK OF THE SNOW WILL FALL OVERNIGHT TUESDAY INTO WEDNESDAY.
THE SNOW WILL RAPIDLY DIMINISH WEDNESDAY MORNING.
USED THE NAM FOR MAX/MIN AND HRLY TEMPS...BLENDED GFS/ECMWF/NAM
FOR WNDS. LOADED RFC/HPC FOR QPF THRU 00Z WED. LOADED A CONSENSUS
BLEND FOR QPF 00Z WED TO 00Z THURS. LOADED BLENDED GFS/ECMWF/NAM
FOR POPS THRU 00Z WED. LOADED POP FROM QPF FOR POPS 00Z WED TO 00Z
THURS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
A LOW PRESSURE AREA WILL BE EAST OF THE AREA MOVING TOWARD THE
CANADIAN MARITIMES. HIGHER PRESSURE WILL BE BUILDING INTO THE AREA
AT THE START OF THE PERIOD. THE RIDGE WILL DOMINATE THE WEATHER
THROUGH EARLY FRIDAY. A LOW PRESSURE AREA MOVING ACROSS THE GREAT
LAKE WILL MOVE INTO EARLY QUEBEC MIDDAY FRI AND THROUGH NRN MAINE
BY EARLY SAT MRNG. A WEAK RIDGE OF HIGHER PRESSURE WILL MOVE
THROUGH THE AREA AND WILL BE EAST OF THE AREA SUN MRNG. THE ECMWF
AND GFS ARE AT ODDS ON THE NEXT SYSTEM TO MOVE INTO THE AREA
TOWARDS THE END OF THE PERIOD. THE GFS INDICATES A BROAD AREA OF
LOWER PRESSURE WITH TWO CENTERS ON SOUTHEAST OF CAPE COD...THE
SECOND CENTER OVER LAKE ONTARIO. THE ECMWF SHOWS A LOW OVER NEW
BRUNSWICK A SECOND LOW OVER VERMONT WITH A FRONTAL BOUNDARY THAT
EXTENDS SW TO THE GULF OF MEXICO. BOTH MODELS INDICATE THAT THEIR
RESPECTIVE SYSTEMS WILL MOVE EAST OF THE AREA BY THE END OF THE
PERIOD.
LOADED THE SUPER BLEND FOR THE EXTENDED PERIOD. SLIT OUT THE POP
GRIDS TO 6 HRLY GRIDS...OTHERWISE JUST MINOR ADJUSTMENTS.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: IFR XPCTD TO CONT LONGEST TNGT ACROSS NRN TAF SITES...
WITH DOWNEAST SITES SLOWLY RECOVERING TO MVFR THIS EVE AND THEN
VFR LATE TNGT.
SHORT TERM: A FEW SCT SNOW SHOWERS ACROSS NRN ME AFFECTING FVE AND
CAR EARLY IN THE PERIOD...OTHERWISE VFR COND ALL SITES 12Z MON
THROUGH 18Z TUES. CIGS WILL BEGIN TO DECREASE SOUTH TO NORTH
AROUND 18Z TUES. VFR COND BHB AND BGR BY 21Z TUE. IFR CONDITIONS
BHB...BGR MVFR HUL BY AROUND 00Z WED IN SNOW. IFR HUL...MVFR
PQI...CAR BY AROUND 03Z. BY AROUND 12Z CONDITIONS WILL BEGIN TO
IMPROVE SW TO E ACROSS THE AREA. BHB AND BGR WILL BEGIN TO BREAK
UP WITH CONTINUOUS SNOW CHANGING OVER TO SHOWERS...CIG AND VSBY
IMPROVING TO MVFR. BY ABOUT 18Z MVFR HUL...VFR BHB AND BGR. ALL
SITES BY THE END OF THE PERIOD.
&&
.MARINE...
NEAR TERM: WILL DOWNGRADE THE CURRENT STORM WRNG TO A SHORT GALE
WRNG INTO THE MID EVE HRS TO ALLOW THE STRONGER WIND GRAD TO MOVE
OF THE WATERS. WOULD THEN XPCT AN SCA FOR LATE THIS EVE INTO THE
OVRNGT MSLY FOR THE OUTER WATERS FOR SEAS AND PERHAPS MARGINAL
WINDS.
SHORT TERM: A GALE WARNING WILL BE NEEDED EARLY IN THE
PERIOD...AN SCA MAYBE REQUIRED LATE IN THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MEZ001-002.
WINTER STORM WARNING UNTIL 9 PM EST THIS EVENING FOR
MEZ003>006-010.
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR MEZ017-
032.
MARINE...GALE WARNING UNTIL 8 PM EST THIS EVENING FOR ANZ050>052.
&&
$$
NEAR TERM...VJN
SHORT TERM...NORTON
LONG TERM...NORTON
AVIATION...VJN/NORTON
MARINE...VJN/NORTON
AREA FORECAST DISCUSSION
NWS CARIBOU ME
225 PM EST SUN DEC 15 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL CONTINUE MOVING EAST OVERNIGHT THROUGH
THE SOUTHERN MARITIMES INTO THE OPEN ATLANTIC. HIGH PRESSURE WILL
APPROACH ON MONDAY AND CREST OVER THE REGION MONDAY NIGHT. LOW
PRESSURE WILL FORM NEAR SOUTHERN NEW ENGLAND ON TUESDAY. THIS LOW
WILL TRACK SOUTH OF THE GULF OF MAINE TUESDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST HOURLY HRRR MODEL OUTPUT SHOWS HEAVIER SN BAND ORGANIZATION
BREAKING DOWN OVR ERN PTNS OF THE FA AND THEN MOVG INTO NEW
BRUNSWICK OVR THE NEXT FEW HRS...LEAVING LGT SNFL MAINLY OVR THE N
HLF OF THE FA INTO THE OVRNGT. WILL HOLD ON TO WNTR STRM WRNGS FOR
NOW...BUT ENVISION THEM BEING DROPPED FROM SW TO NE BEGINNING
WITHIN THE NEXT FEW HRS...WITH EVEN NRN ZONES BEING DROPPED...SINCE
SN RATES AND ACCUMULATIONS WILL BE TO LOW TO SUSTAIN IMPACT...AND
NEARLY ALL...IF NOT ALL OF THE CURRENT WRNGS HAVE ALREADY BEEN
VERIFIED WITH SNFL THAT HAS FALLEN TO THIS POINT.
OTHERWISE...SFC TEMPS WILL BE FALLING W AND DOWNEAST INTO THE EVE
AND SLOWLY RISING ACROSS THE N AND E DUE TO DIFFERENTIAL THERMAL`
ADVCN ACROSS THE FA. TEMPS MAY COOL OVR THE NE BY DAYBREAK...BUT
NOT BY MUCH AS A LLVL THERMAL RIDGE HANGS ON AND LLVL COLD ADVCN
BEGINS TO PUNCH EWRD ACROSS WRN AND DOWNEAST AREAS. WINDS SHOULD
DIMINISH THROUGH THE EVENING AND OVRNGT AS THE LLVL PRES GRAD
SLACKENS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
A TROUGH OF LOWER PRESSURE EXTENDS ACROSS NORTHERN MAINE AND HIGH
PRESSURE RIDGE BUILDS INTO WESTERN MAINE AT THE START OF THE
PERIOD. A FEW LINGERING SNOW SHOWERS EARLY...THEN CLEARING. THE
HIGH PRESSURE WILL MOVE EAST OF THE AREA LATE TUESDAY AS THE NEXT
LOW MOVES INTO THE GULF OF MAINE. THE MODELS ARE AT A BIT OF
DISAGREEMENT ON THE POSITION AND MOVEMENT OF THE LOW AS IT EXITS
INTO THE NORTH ATLANTIC. THE ECMWF...NAM...GEM KEEP THE LOW IN THE
NORTHERN PORTIONS OF THE GULF OF MAINE. WITH THE ECMWF AND GEM THE
FARTHEST NORTH. THE GFS MOVES THE LOW OFF THE COAST SOUTH OF CAPE
COD AND MOVES IT EAST WELL SOUTH OF NOVA SCOTIA. A CONSENSUS
FORECAST OF THE ECMWF...NAM...AND GEM BRINGS THE HIGHEST POPS AND
QPF INTO THE SOUTHEASTERN AND EASTERN PORTIONS OF THE AREA. THE
CONSENSUS BLEND FOR QPF GIVES ABOUT THREE TENTHS OF AN INCH IN THE
HOULTON AREA...ABOUT SIX TENTHS OF AN INCH INTO THE ELSWORTH AREA.
THE BULK OF THE SNOW WILL FALL OVERNIGHT TUESDAY INTO WEDNESDAY.
THE SNOW WILL RAPIDLY DIMINISH WEDNESDAY MORNING.
USED THE NAM FOR MAX/MIN AND HRLY TEMPS...BLENDED GFS/ECMWF/NAM
FOR WNDS. LOADED RFC/HPC FOR QPF THRU 00Z WED. LOADED A CONSENSUS
BLEND FOR QPF 00Z WED TO 00Z THURS. LOADED BLENDED GFS/ECMWF/NAM
FOR POPS THRU 00Z WED. LOADED POP FROM QPF FOR POPS 00Z WED TO 00Z
THURS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
A LOW PRESSURE AREA WILL BE EAST OF THE AREA MOVING TOWARD THE
CANADIAN MARITIMES. HIGHER PRESSURE WILL BE BUILDING INTO THE AREA
AT THE START OF THE PERIOD. THE RIDGE WILL DOMINATE THE WEATHER
THROUGH EARLY FRIDAY. A LOW PRESSURE AREA MOVING ACROSS THE GREAT
LAKE WILL MOVE INTO EARLY QUEBEC MIDDAY FRI AND THROUGH NRN MAINE
BY EARLY SAT MRNG. A WEAK RIDGE OF HIGHER PRESSURE WILL MOVE
THROUGH THE AREA AND WILL BE EAST OF THE AREA SUN MRNG. THE ECMWF
AND GFS ARE AT ODDS ON THE NEXT SYSTEM TO MOVE INTO THE AREA
TOWARDS THE END OF THE PERIOD. THE GFS INDICATES A BROAD AREA OF
LOWER PRESSURE WITH TWO CENTERS ON SOUTHEAST OF CAPE COD...THE
SECOND CENTER OVER LAKE ONTARIO. THE ECMWF SHOWS A LOW OVER NEW
BRUNSWICK A SECOND LOW OVER VERMONT WITH A FRONTAL BOUNDARY THAT
EXTENDS SW TO THE GULF OF MEXICO. BOTH MODELS INDICATE THAT THEIR
RESPECTIVE SYSTEMS WILL MOVE EAST OF THE AREA BY THE END OF THE
PERIOD.
LOADED THE SUPER BLEND FOR THE EXTENDED PERIOD. SLIT OUT THE POP
GRIDS TO 6 HRLY GRIDS...OTHERWISE JUST MINOR ADJUSTMENTS.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: IFR XPCTD TO CONT LONGEST TNGT ACROSS NRN TAF SITES...
WITH DOWNEAST SITES SLOWLY RECOVERING TO MVFR THIS EVE AND THEN
VFR LATE TNGT.
SHORT TERM: A FEW SCT SNOW SHOWERS ACROSS NRN ME AFFECTING FVE AND
CAR EARLY IN THE PERIOD...OTHERWISE VFR COND ALL SITES 12Z MON
THROUGH 18Z TUES. CIGS WILL BEGIN TO DECREASE SOUTH TO NORTH
AROUND 18Z TUES. VFR COND BHB AND BGR BY 21Z TUE. IFR CONDITIONS
BHB...BGR MVFR HUL BY AROUND 00Z WED IN SNOW. IFR HUL...MVFR
PQI...CAR BY AROUND 03Z. BY AROUND 12Z CONDITIONS WILL BEGIN TO
IMPROVE SW TO E ACROSS THE AREA. BHB AND BGR WILL BEGIN TO BREAK
UP WITH CONTINUOUS SNOW CHANGING OVER TO SHOWERS...CIG AND VSBY
IMPROVING TO MVFR. BY ABOUT 18Z MVFR HUL...VFR BHB AND BGR. ALL
SITES BY THE END OF THE PERIOD.
&&
.MARINE...
NEAR TERM: WILL DOWNGRADE THE CURRENT STORM WRNG TO A SHORT GALE
WRNG INTO THE MID EVE HRS TO ALLOW THE STRONGER WIND GRAD TO MOVE
OF THE WATERS. WOULD THEN XPCT AN SCA FOR LATE THIS EVE INTO THE
OVRNGT MSLY FOR THE OUTER WATERS FOR SEAS AND PERHAPS MARGINAL
WINDS.
SHORT TERM: A GALE WARNING WILL BE NEEDED EARLY IN THE
PERIOD...AN SCA MAYBE REQUIRED LATE IN THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MEZ001-002.
WINTER STORM WARNING UNTIL 9 PM EST THIS EVENING FOR
MEZ003>006-010.
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR MEZ011-
015>017-029>032.
MARINE...GALE WARNING UNTIL 8 PM EST THIS EVENING FOR ANZ050>052.
&&
$$
NEAR TERM...VJN
SHORT TERM...NORTON
LONG TERM...NORTON
AVIATION...VJN/NORTON
MARINE...VJN/NORTON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
635 PM EST MON DEC 16 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 347 PM EST MON DEC 16 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOWS PERSISTENT NW
FLOW ALF OVER THE GREAT LKS BTWN DEEP TROF OVER ERN NAMERICA AND RDG
ALONG THE W COAST. VERY COLD CNDN AIR IS IN PLACE OVER THE UPR LKS
WITH H5/H85 TEMPS JUST UNDER -30C/ARND -18 OR 19C. DISTURBANCE
RESPONSIBLE FOR SN ON SUN HAS NOW PUSHED E INTO QUEBEC...BUT ANOTHER
WELL DEFINED CLIPPER SHRTWV JUST E OF LK WINNIPEG EARLY THIS AFTN IS
FOLLOWING QUICKLY BEHIND. SHRTWV RDG/DRY MID LVL AIR SHOWN ON THE
12Z APX/GRB RAOBS BROUGHT DRY WX TO UPR MI EARLY THIS AFTN. ALTHOUGH
ABSOLUTE MSTR IS LIMITED FOR THE TRAILING DISTURBANCE WITH 12Z PWATS
NO HIER THAN 0.25-0.35 INCH IN MN...A BAND OF SN UNDER THE DEEP LYR
QVECTOR CNVGC/DPVA/ISENTROPIC ASCENT AHEAD OF THIS FEATURE IS MOVING
INTO WRN LK SUP. THE BAND IS RATHER NARROW...BUT VSBYS UNDER THE
HEAVIER SN HAVE FALLEN AS LO AS 1/4-3/4 MILES. THIS SN BAND SHIFTED
INTO THE WRN COUNTIES BY MID AFTN...AND THE VSBY AT IWD DROPPED TO
1/4SM FOR AN HR. SOME SHSN AND PERHAPS A VORTEX ARE PRESENT OVER
NCNTRL LK MI...AND THESE ARE DRIFTING TO THE NNE. ALTHOUGH SOME
LIGHT SN LINGERS BACK INTO NW MN BEHIND THIS BAND...VSBYS THERE ARE
AOA 3 MILES UNDER THE UPR LVL DRYING SHOWN ON WV IMAGERY/QVECTOR
DVGC IN THE WAKE OF THE SHRTWV TROF. IN FACT...THERE HAS BEEN SOME
CLRG OVER CENTRAL MN. FARTHER TO THE NW...THERE IS ANOTHER CLIPPER
DISTURBANCE DIGGING SEWD IN SASKATCHEWAN.
MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE POPS/SN AMNTS AND GOING
HEADLINE OVER THE ERN CWA ASSOCIATED WITH APRCHG CLIPPER SHRTWV.
FOCUS FOR TUE SHIFTS TO POTENTIAL IMPACT OF SECOND TRAILING
DISTURBANCE IN WRN CANADA AS WELL AS THE CHC FOR MORE LK EFFECT SN.
LATE THIS AFTN/THRU THIS EVNG...TENDED TO BUMP POPS UP TO
CATEGORICAL FOR A FEW HRS AT MOST PLACES W-E THIS AFTN INTO EARLY
EVNG WITH PASSAGE OF RATHER NARROW BAND OF SN UNDER AXIS OF H85-5
QVECTOR CNVGC AHEAD OF APRCHG SHRTWV. WITH 2G/KG SPECIFIC HUMIDITY
PRESENT NEAR H725 AND A 2-3 HR PERIOD OF HEAVIER SN...EXPECT MOST
PLACES WL SEE ARND AN INCH TO PERHAPS 2 INCHES OF SN UNDER THIS
HEAVIER BURST. THE ONE EXCEPTION WL BE IN THE SSW FLOW DOWNWIND OF
LK MI...WHERE SOME LK ENHANCEMENT WITH H85 TEMPS NEAR -16C/DEEPER
MSTR/DYNAMIC FORCING JUSTIFIES GOING WINTER WX ADVY UNTIL PASSAGE OF
THE BAND/WSHFT TO THE WSW AFT MIDNGT OVER THE E WL DIMINISH THESE
SHSN. FVRBL OMEGA PROFILE WITHIN THE DGZ WL AID IN SN ACCUMS. TO THE
W...JUST SOME LINGERING SCT -SHSN WL FOLLOW THE BAND UNDER MID LVL
DRYING/QVECTOR DVGC. WHERE THERE IS A BETTER CHC FOR AT LEAST
PARTIAL CLRG OVER THE SCNTRL...TENDED TO LOWER FCST MIN TEMPS A BIT
WELL INTO THE SINGLE NUMBERS ABV ZERO.
LATER TNGT/TUE...MOST OF THE EARLY MRNG SHOULD BE MOCLDY WITH JUST
SOME SCT -SHSN/FLURRIES UNDER QVECTOR DVGC IN THE WAKE OF THE
DEPARTING CLIPPER. THE SHRTWV NOW OVER SASKATCHEWAN IS FCST TO DIG
SEWD AND INTO THE UPR LKS BY 12Z TUE. ALTHOUGH MORE IMPRESSIVE
MSTR/DYNAMIC FORCING WL ACCOMPANY ANOTHER SHRTWV PASSING TO THE S IN
WI...ARRIVAL OF COLD FNT/DEEPER MSTR ASSOCIATED WITH THE
SASKATCHEWAN DISTURBANCE WL BRING A RETURN OF HIER POPS TO MAINLY NW
UPR MI ON TUE MRNG. THERE IS SOME DISAGREEMENT AMONG THE MODELS ON
HOW MUCH DEEPER MSTR WL ACCOMPANY THIS FROPA. IN GENERAL...THE 12Z
NAM/GFS SHOW MORE FVRBL ALIGNMENT BTWN THE DEEPER MSTR AND FROPA
TIMING. ALTHOUGH THERE IS SOME POTENTIAL FOR A BRIEF PERIOD OF LK
ENHANCED SN WITH H85 TEMPS RISING TO -10C IN THE NARROW THERMAL RDG
AHEAD OF THIS FNT...THE NAM/GFS SHOW DEEPER MSTR LINGERING FOR ONLY
A 3-6HR PERIOD. AS THE FNT SHIFTS TO THE E...THESE SHSN WL FOLLOW
THE BNDRY...WITH THE HIER POPS CLOSER TO LK SUP. BUT WL CARRY LOWER
CHC POPS EVEN OVER THE SCENTRAL...WHICH WL BE CLOSER TO THE DYNAMIC
FORCING ASSOCIATED WITH SHRTWV PASSING THRU WI. AFTER THE HEAVIER
SHSN END OVER THE NW...EXPECT LIGHTER MULTIPLE BAND LES TO IMPACT
THE WNW WIND SN BELTS THERE AS COLDER AIR WITH H85 TEMPS FALLING TO
ARND -18C BY 00Z WED FOLLOW THE BNDRY. NOT OUT OF THE QUESTION THERE
COULD BE ADVY SN FALL OVER THE NW THRU THE DAY...BUT CONCERNS
ABOUT TIMING OF DEEPER MSTR LOWER CONFIDENCE ENUF TO HOLD OFF ON A
HEADLINE FOR NOW.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 440 PM EST MON DEC 16 2013
EXPECT CONTINUED NW FLOW OVER THE KEWEENAW PENINSULA TUESDAY EVENING
WITH ANOTHER 1 TO ALMOST 2IN. A QUICK 1-4IN OF SNOW WILL BE POSSIBLE
E OF MUNISING AND N OF NEWBERRY TUESDAY NIGHT. MAY NEED TO HOIST A
LES ADVISORY FOR E ALGER AND N PORTIONS OF LUCE COUNTY...WITH THE
CONVERGENCE BEHIND THE EXITING LOW.
WITH THE 500MB TROUGH SET UP FROM E ONTARIO THROUGH THE LOWER GREAT
LAKES...AND A SIZABLE RIDGE DOMINATING THE W HALF OF THE
NATION...CHANCES ARE GOOD FOR RIDGING TO MOVE IN FOR MID WEEK. THE
RIDGE WILL SLIDE IN AT THE SFC AND ALOFT WEDNESDAY MORNING...AHEAD
OF A BROAD AREA OF LOW PRESSURE SET UP FROM SW AND SCENTRAL CANADA
THROUGH THE NORTHERN PLAINS. THE WARM WEATHER WILL CONTINUE FOR
WEDNESDAY AHEAD OF THIS LOW. ENJOY IT WHILE IT LASTS. WHILE READINGS
WILL BE ABOVE WHAT WE HAVE BEEN USE TO /HAVE NOT HAD TEMPS ABOVE 15F
AT NWS MQT SINCE THE FIRST 5 DAYS OF DECEMBER/...THEY WILL REMAIN
AROUND NORMAL FOR THIS TIME OF YEAR. HIGHS ARE TYPICALLY IN THE MID
TO UPPER 20S IN MID DECEMBER.
EXPECT THE RIDGE ALOFT TO QUICKLY TURNING TO MORE ZONAL FLOW
WEDNESDAY NIGHT WITH BOOKEND TROUGHS OVER THE FAR W AND E SECTIONS
OF THE UNITED STATES. BY 00Z THURSDAY THE SFC LOW WILL HAVE MOVED TO
THE SE...STRETCHING FROM E CO THROUGH LAKE SUPERIOR.
THE N EXTENT OF THE SFC LOW WILL SLOWLY SINK ACROSS LAKE MI AND
LOWER MI THROUGH THE DAY THURSDAY...WITH SW FLOW AT 500MB ON
THURSDAY IN RESPONSE TO THE LOW DIVING ALONG THE W COAST INTO
CA...AND THE NORTHERN LOW PUSHING ACROSS CENTRAL CANADA. A QUICK
TENTH OF AN INCH OR SO OF LIQUID FROM THURSDAY AFTERNOON THROUGH
THURSDAY EVENING. WITH SNOW RATIOS OF 20-25:1...WILL LIKELY HAVE
1-2IN OF SNOW CWA WIDE BY MIDNIGHT.
THE SFC LOW WILL THEN CONSOLIDATE ACROSS LOWER MI AND LAKE HURON AT
12Z FRIDAY...WITH UPPER MI AND THE UPPER GREAT LAKES RETURNING TO
OUR TROUGH PATTERN FROM THURSDAY THROUGH NEXT MONDAY. ANOTHER 1-2IN
OF SNOW POSSIBLE BEFORE DRYING UP BY LATE FRIDAY MORNING.
A BRIEF RIDGE WILL ATTEMPT TO BUILD IN ALOFT SATURDAY OVER THE SE
CWA...AS THE NEXT SIGNIFICANT TROUGH PUSHES IN FROM CENTRAL CANADA
AND THE PLAINS STATES. A SERIES OF EMBEDDED WAVES WILL CONTINUE TO
NEAR FROM THE NW THROUGH AT LEAST MONDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 635 PM EST MON DEC 16 2013
A SERIES OF SHORTWAVE TROUGHS COMBINED WITH UPSLOPE FLOW AT CMX WILL
BRING PERIODS OF LOWER CONDITIONS THROUGH THE TAF PERIOD AT ALL
SITES. THE WORST CONDITIONS ARE EXPECTED AT CMX WHERE UPSLOPE FLOW
WILL FAVOR LOWER CIGS AND HEAVIER SNOW. SKIES MAY CLEAR OUT TONIGHT
AT IWD AS SCATTERED CLEARING WAS NOTED UPSTREAM OVER NCENTRAL
MN...BUT NOT COMPLETELY CERTAIN ON EXTENT OF CLEARING THERE. LOW
LEVEL FLOW WILL NOT BE AS FAVORABLE AT SAW...SO BEST CONDITIONS ARE
EXPECTED THERE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 355 PM EST MON DEC 16 2013
S WINDS UP TO 25 TO 30 KTS THIS AFTERNOON AHEAD OF AN APPROACHING
LOW PRESSURE TROUGH WILL SHIFT TO THE SW AND DIMINISH OVERNIGHT TO
20 TO 25 KTS AS THE TROUGH SHIFTS TO THE EAST. A STRONGER WEST TO
NORTHWEST WIND UP TO 30 KTS WILL DEVELOP ON TUE FOLLOWING THE
PASSAGE OF A COLD FRONT. NOT OUT OF THE QUESTION THERE COULD BE A
FEW GUSTS TO NEAR GALE FORCE OVER WESTERN LAKE SUPERIOR. NO GALES
ARE FORESEEN QUITE YET FROM TUESDAY NIGHT THROUGH
SATURDAY...ALTHOUGH A COUPLE OF PERIODS GET CLOSER TO GUSTS OF
25-30KTS. HIGH PRESSURE WILL MOVE INTO THE CENTRAL PLAINS TUESDAY
EVENING AND WILL PUSH A BRIEF RIDGE ACROSS LAKE SUPERIOR WEDNESDAY.
A TROUGH EXTENDING FROM A BROAD LOW OVER THE ROCKIES AND NORTHERN
PLAINS WILL MOVE INTO THE UPPER GREAT LAKES WEDNESDAY NIGHT AND
THURSDAY. EXPECT THE LOW TO SINK ACROSS LOWER MICHIGAN BY FRIDAY
MORNING. IN THE WAKE OF THE LOW...HIGH PRESSURE OVER THE CENTRAL
PLAINS FRIDAY MORNING SHOULD SLOWLY BUILD INTO THE UPPER GREAT LAKES
ON FRIDAY...AND REMAIN IN PLACE THROUGH FRIDAY NIGHT. WEAK LOW
PRESSURE WILL THEN PUSH ACROSS THE AREA FOR THE START OF THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 AM EST TUESDAY FOR MIZ007-014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...TITUS
MARINE...KC/KF
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1228 PM EST SUN DEC 15 2013
.AVIATION...
//DISCUSSION...
A SURFACE TROUGH IS JUST ABOUT THROUGH SOUTHEAST MICHIGAN...AND
WESTERLY WINDS WILL BE GUSTING TO AROUND 25 KNOTS EARLY THIS
AFTERNOON BEHIND THE TROUGH PASSAGE. FLURRIES AND LIGHT SNOW
SHOWERS WILL PROBABLY PERSIST SEVERAL MORE HOURS...BUT DRIER AIR
(MID LEVELS) WILL SHRINK CLOUD DEPTHS. THIS EVENING AND TONIGHT IS
TOUGH CALL FOR CLOUD COVER...AND BANKING ON THE COLD WESTERLY FLOW
OFF LAKE MICHIGAN TO PROVIDE JUST ENOUGH MOISTURE TO MAINTAIN HIGH
MVFR/LOW VFR CEILINGS. IN ADDITION...THE VERY COLD AIRMASS WILL
SUPPORT THE CHANCE OF FLURRIES JUST ABOUT ANYTIME...BUT ESPECIALLY
TOMORROW MORNING AS SOME MID LEVEL MOISTURE ALSO RETURNS TO THE
AREA.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5 KFT FT THROUGH THIS
EVENING...MEDIUM CONFIDENCE OVERNIGHT INTO TOMORROW MORNING
* MODERATE CONFIDENCE IN WESTERLY GUSTS REACHING 25KTS THIS AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 855 AM EST SUN DEC 15 2013
UPDATE...
QUICK UPDATE TO CARRY WIDESPREAD SNOW SHOWERS...AS FLAKE SIZE IS
PRETTY GOOD WITH SURFACE OBS REPORTING VSBYS 1-3 SM WITHIN THE
HEAVIER ACTIVITY. 12Z DTX SOUNDING DOES SHOW STEEP LAPSE RATE IN
THE 875-825 MB LAYER...WHICH IS EMBEDDED IN THE DENDRITIC SNOW
GROWTH REGION. SURFACE TROUGH IS PROVIDING SUFFICIENT LOW LEVEL
CONVERGENCE AS WELL. WITH GOOD FLUFF FACTOR...ACCUMULATIONS
AROUND 1 INCH ARE EXPECTED.
PREV DISCUSSION...ISSUED 357 AM EST SUN DEC 15 2013
SHORT TERM...TODAY AND TONIGHT
THE SHORT TERM WILL FEATURE LIGHT SNOW...GUSTY AFTERNOON WINDS...AND
POSSIBLE SINGLE DIGIT TEMPS OVERNIGHT. A NORTHERN STREAM UPPER LEVEL
LOW WILL DROP THROUGH THE NORTHERN GREAT LAKES TODAY WHILE A LAKE
AGGREGATE SURFACE TROUGH LINGERS ACROSS CENTRAL MI. STRONG CAA HAS
BEGUN IN THE WAKE OF SATURDAYS LOW AS BROAD MID LEVEL TROUGHING
SINKS INTO THE GREAT LAKES. THIS WILL USHER IN ANOTHER ARCTIC
AIRMASS TO DEAL WITH THROUGH TONIGHT. MODELS SHOW SOME AIRMASS
MODIFICATION AS IT CROSSES THE LAKES WITH -26C TEMPS AT 850MB
ENTERING LAKE SUPERIOR AND NEGATIVE TEENS ENTERING MI. SOUTHERN MI
WILL FALL NEAR THE BASE OF THE MID LEVEL TROUGH AND ON THE SOUTH
SIDE OF THE SFC TROUGH LEADING TO WESTERLY FLOW. THE WESTERLY FLOW
AND CAA WILL LEAD TO AN ACTIVE SETUP FOR LAKE EFFECT WITH MIXING
LEVELS OVER LAKE MI REACHING 10KFT. EVEN OVER SE MI THE CAA IN THE
LOW LEVELS WILL LEAD TO STRONG LAPSE RATES UP TO ABOUT 6KFT. BOTH
THE NAM AND RUC SHOW THE ENTIRE MIXED LAYER TO BE SATURATED WHICH
EXTENDS THROUGH THE DGZ. IN ADDITION TO THE SFC FEATURES...A MID
LEVEL VORT MAX WILL ROTATE AROUND AND THROUGH MID MI LENDING SOME
ADDITIONAL SYNOPTIC SUPPORT ALOFT. POPS WILL RAMP UP IN THE
AFTERNOON AS THE DIURNAL CYCLE GIVES THE MIXED LAYER A BOOST AND AS
THE SFC TROUGH AND VORT MAX SWING THROUGH. LAKE EFFECT SHOULD MAKE
IT INTO THE CWA WITH THE STEADY WESTERLY FLOW DURING THE DAY. THE
NAM IS ADVERTISING THE LAKE MI CONVERGENT BAND SETTING UP WHICH WILL
NEED TO BE WATCHED IN CASE IT IMPACTS ANY ONE AREA FOR ANY
DURATION...MOST LIKELY NEAR THE I94 CORRIDOR. OVERALL NOT EXPECTING
MUCH SNOW WITH AROUND A HALF INCH FOR MOST LOCATIONS. IF WE CAN GET
SOME ENHANCE MESOSCALE FEATURES TO SET UP OR THE LAKE EFFECT BAND TO
PERSIST...TOTALS WOULD OBVIOUSLY GO UP SOME. THE OTHER CONCERN TODAY
WILL BE THE WINDS. MODEL SOUNDINGS SHOW THE MIXING LEVELS PREVIOUSLY
MENTIONED BRINGING DOWN GUST AROUND 30 MPH IN THE AFTERNOON. THIS
WILL LIKELY LEAD TO ADDITIONAL DRIFTING OF THE SNOW PACK. THE LAST
CONCERN WILL BE LOW TEMPS TONIGHT. WITH THE FRESH SNOW PACK AND
ARCTIC AIR MOVING IN...THE POTENTIAL IS THERE FOR LOW SINGLE DIGIT
TEMPS. A BIG CONCERN WILL BE CLOUD COVER PREVENTING THIS FROM
ACTUALLY OCCURRING...ESPECIALLY ACROSS THE SOUTH WHERE THE LAKE
CLOUD SHOULD PERSIST THE LONGEST. ADJUSTED TEMPS UP A COUPLE DEGREES
ACROSS THE SOUTH WITH THE MORE PESSIMISTIC CLOUD COVER
FORECAST...OTHERWISE CONTINUED THE COOL PLAY IN THE MID SINGLE
DIGITS RESULTING IN WIND CHILL VALUES -5 TO -10F.
LONG TERM...MONDAY THROUGH SATURDAY
SHORTWAVE RIDGING WILL TRACK THROUGH THE CENTRAL GREAT LAKES MONDAY
MORNING...KEEPING THE WEATHER DRY FOR THE FIRST HALF OF THE DAY.
QUICKLY ON ITS HEELS WILL BE A VIGOROUS MID LEVEL SHORTWAVE DIVING
SOUTH FROM CANADA. THIS ELONGATED MID LEVEL TROUGH...SEEN ON WATER
VAPOR OVER WESTERN CANADA...WILL BRING A PROLONGED PERIOD OF LIGHT
SNOW SHOWERS FROM MONDAY AFTERNOON THROUGH TUESDAY TO SOUTHEAST
MICHIGAN. AS THE TROUGH MOVES THROUGH THE GREAT LAKES...IT WILL HAVE
THE ASSISTANCE OF BEING UNDER THE LEFT EXIT REGION OF A 140 KNOT JET
DIVING INTO THE WESTERN GREAT LAKES REGION. THE BEST TIME FOR SNOW
APPEARS TO BE LATE MONDAY AFTERNOON INTO MONDAY NIGHT WHEN THE LEAD
SHORTWAVE TRACKS THROUGH THE CENTRAL GREAT LAKES...WITH AN INCH OF
TWO OF SNOWFALL ACCUMULATION POSSIBLE. A SUBTLE BUT NOTICEABLE
WARMING IN THE LOW LEVELS SHOULD CAUSE LOW TEMPERATURES TO OCCUR
EARLY MONDAY NIGHT...WITH SLOWLY RISING TEMPERATURES AFTER MIDNIGHT.
ANOTHER SHORTWAVE TRACKING THROUGH THE SOUTHERN GREAT LAKES ON
TUESDAY COULD BRING ADDITIONAL SNOWFALL AMOUNTS OF A FEW TENTHS OF
AN INCH TO SOUTHEAST MICHIGAN.
ONCE THIS SYSTEM MOVES OFF TO THE EAST HEIGHTS WILL INCREASE ACROSS
THE CENTRAL GREAT LAKES WITH TEMPERATURES WARMING INTO THE 30S ON
THURSDAY...WITH 40S POSSIBLE BY FRIDAY AHEAD OF THE NEXT LOW
PRESSURE SYSTEM TRACKING THROUGH THE GREAT LAKES REGION. THIS
SYSTEM...ORIGINATING OVER THE SOUTHERN PLAINS ON THURSDAY...WILL
TRACK NORTHEAST THROUGH MICHIGAN ON FRIDAY. GIVEN THE NORTHERN TRACK
OF THE LOW THE AREA WILL BE IN THE WARM SECTOR OF THE
SYSTEM...MEANING PRECIPITATION MORE IN THE FORM OF LIQUID RATHER
THAN ICE CRYSTALS. THERE ARE STILL TIMING DIFFERENCES BETWEEN THE
LONG RANGE MODELS...NOTABLY THE FASTER ECMWF AND THE SLOWER GFS.
HOWEVER THEY DO AGREE ON A RETURN TO COLDER TEMPERATURES BEHIND THE
LOW BY SATURDAY AS RIDGING BUILDS OVER THE CENTRAL GREAT LAKES.
MARINE...
WAVES IN THE NEARSHORE ZONES CONTINUE TO SUBSIDE...WITH CONDITIONS
HAVING FALLEN BELOW HEADLINE CRITERIA. HOWEVER...INCREASING WESTERLY
WINDS THIS AFTERNOON ARE EXPECTED AS LOW PRESSURE TRACKS THROUGH THE
CENTRAL GREAT LAKES. THE FETCH WILL BE FAVORABLE FOR WAVES TO BUILD
UP OVER THE NORTHERN TIP OF THE THUMB OVERNIGHT...NECESSITATING A
SMALL CRAFT ADVISORY FOR OUTER SAGINAW BAY AND THE LAKE HURON
NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH. CONDITIONS WILL
REMAIN UNSETTLED INTO EARLY NEXT WEEK AS SOUTHWEST WINDS DEVELOP
AHEAD OF A PASSING SYSTEM MONDAY NIGHT INTO TUESDAY. THERE ARE NO
SIGNIFICANT WIND EVENTS ON THE HORIZON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SF
UPDATE.......SF
SHORT TERM...DRK
LONG TERM....KURIMSKI
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
855 AM EST SUN DEC 15 2013
.UPDATE...
QUICK UPDATE TO CARRY WIDESPREAD SNOW SHOWERS...AS FLAKE SIZE IS
PRETTY GOOD WITH SURFACE OBS REPORTING VSBYS 1-3 SM WITHIN THE
HEAVIER ACTIVITY. 12Z DTX SOUNDING DOES SHOW STEEP LAPSE RATE IN
THE 875-825 MB LAYER...WHICH IS EMBEDDED IN THE DENDRITIC SNOW
GROWTH REGION. SURFACE TROUGH IS PROVIDING SUFFICIENT LOW LEVEL
CONVERGENCE AS WELL. WITH GOOD FLUFF FACTOR...ACCUMULATIONS
AROUND 1 INCH ARE EXPECTED.
&&
.AVIATION...ISSUED 559 AM EST SUN DEC 15 2013
//DISCUSSION...
CONDITIONS SHOULD STAY MVFR THROUGH THE DAY FOR CIGS WITH POTENTIAL
FOR NON VFR VSBYS THIS AFTERNOON AS COVERAGE OF SNOW SHOWERS
INCREASES. WESTERLY WINDS WILL INCREASE AS DEEPER MIXING OCCURS THIS
AFTERNOON WITH GUSTS UP TO 25 KNOTS POSSIBLE. MODELS STILL TRYING TO
SCATTER OUT CLOUDS...AND POSSIBLY BECOME CLEAR OVERNIGHT.
FOR DTW...LIGHT SNOW SHOWERS WILL POSSIBLY OCCUR THIS AFTERNOON AS
LAKE EFFECT SNOW EXTENDS EASTWARD ACROSS LOWER MI. WESTERLY WINDS
WILL INCREASE THROUGH THE MORNING WITH GUSTS LIKELY ECLIPSING 25KTS
THIS AFTERNOON OUT OF ABOUT 270-280 DEGREES.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5KFT FT THROUGH THIS EVENING.
* MODERATE CONFIDENCE IN WESTERLY GUSTS EXCEEDING 25KTS SUNDAY
AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 357 AM EST SUN DEC 15 2013
SHORT TERM...TODAY AND TONIGHT
THE SHORT TERM WILL FEATURE LIGHT SNOW...GUSTY AFTERNOON WINDS...AND
POSSIBLE SINGLE DIGIT TEMPS OVERNIGHT. A NORTHERN STREAM UPPER LEVEL
LOW WILL DROP THROUGH THE NORTHERN GREAT LAKES TODAY WHILE A LAKE
AGGREGATE SURFACE TROUGH LINGERS ACROSS CENTRAL MI. STRONG CAA HAS
BEGUN IN THE WAKE OF SATURDAYS LOW AS BROAD MID LEVEL TROUGHING
SINKS INTO THE GREAT LAKES. THIS WILL USHER IN ANOTHER ARCTIC
AIRMASS TO DEAL WITH THROUGH TONIGHT. MODELS SHOW SOME AIRMASS
MODIFICATION AS IT CROSSES THE LAKES WITH -26C TEMPS AT 850MB
ENTERING LAKE SUPERIOR AND NEGATIVE TEENS ENTERING MI. SOUTHERN MI
WILL FALL NEAR THE BASE OF THE MID LEVEL TROUGH AND ON THE SOUTH
SIDE OF THE SFC TROUGH LEADING TO WESTERLY FLOW. THE WESTERLY FLOW
AND CAA WILL LEAD TO AN ACTIVE SETUP FOR LAKE EFFECT WITH MIXING
LEVELS OVER LAKE MI REACHING 10KFT. EVEN OVER SE MI THE CAA IN THE
LOW LEVELS WILL LEAD TO STRONG LAPSE RATES UP TO ABOUT 6KFT. BOTH
THE NAM AND RUC SHOW THE ENTIRE MIXED LAYER TO BE SATURATED WHICH
EXTENDS THROUGH THE DGZ. IN ADDITION TO THE SFC FEATURES...A MID
LEVEL VORT MAX WILL ROTATE AROUND AND THROUGH MID MI LENDING SOME
ADDITIONAL SYNOPTIC SUPPORT ALOFT. POPS WILL RAMP UP IN THE
AFTERNOON AS THE DIURNAL CYCLE GIVES THE MIXED LAYER A BOOST AND AS
THE SFC TROUGH AND VORT MAX SWING THROUGH. LAKE EFFECT SHOULD MAKE
IT INTO THE CWA WITH THE STEADY WESTERLY FLOW DURING THE DAY. THE
NAM IS ADVERTISING THE LAKE MI CONVERGENT BAND SETTING UP WHICH WILL
NEED TO BE WATCHED IN CASE IT IMPACTS ANY ONE AREA FOR ANY
DURATION...MOST LIKELY NEAR THE I94 CORRIDOR. OVERALL NOT EXPECTING
MUCH SNOW WITH AROUND A HALF INCH FOR MOST LOCATIONS. IF WE CAN GET
SOME ENHANCE MESOSCALE FEATURES TO SET UP OR THE LAKE EFFECT BAND TO
PERSIST...TOTALS WOULD OBVIOUSLY GO UP SOME. THE OTHER CONCERN TODAY
WILL BE THE WINDS. MODEL SOUNDINGS SHOW THE MIXING LEVELS PREVIOUSLY
MENTIONED BRINGING DOWN GUST AROUND 30 MPH IN THE AFTERNOON. THIS
WILL LIKELY LEAD TO ADDITIONAL DRIFTING OF THE SNOW PACK. THE LAST
CONCERN WILL BE LOW TEMPS TONIGHT. WITH THE FRESH SNOW PACK AND
ARCTIC AIR MOVING IN...THE POTENTIAL IS THERE FOR LOW SINGLE DIGIT
TEMPS. A BIG CONCERN WILL BE CLOUD COVER PREVENTING THIS FROM
ACTUALLY OCCURRING...ESPECIALLY ACROSS THE SOUTH WHERE THE LAKE
CLOUD SHOULD PERSIST THE LONGEST. ADJUSTED TEMPS UP A COUPLE DEGREES
ACROSS THE SOUTH WITH THE MORE PESSIMISTIC CLOUD COVER
FORECAST...OTHERWISE CONTINUED THE COOL PLAY IN THE MID SINGLE
DIGITS RESULTING IN WIND CHILL VALUES -5 TO -10F.
LONG TERM...MONDAY THROUGH SATURDAY
SHORTWAVE RIDGING WILL TRACK THROUGH THE CENTRAL GREAT LAKES MONDAY
MORNING...KEEPING THE WEATHER DRY FOR THE FIRST HALF OF THE DAY.
QUICKLY ON ITS HEELS WILL BE A VIGOROUS MID LEVEL SHORTWAVE DIVING
SOUTH FROM CANADA. THIS ELONGATED MID LEVEL TROUGH...SEEN ON WATER
VAPOR OVER WESTERN CANADA...WILL BRING A PROLONGED PERIOD OF LIGHT
SNOW SHOWERS FROM MONDAY AFTERNOON THROUGH TUESDAY TO SOUTHEAST
MICHIGAN. AS THE TROUGH MOVES THROUGH THE GREAT LAKES...IT WILL HAVE
THE ASSISTANCE OF BEING UNDER THE LEFT EXIT REGION OF A 140 KNOT JET
DIVING INTO THE WESTERN GREAT LAKES REGION. THE BEST TIME FOR SNOW
APPEARS TO BE LATE MONDAY AFTERNOON INTO MONDAY NIGHT WHEN THE LEAD
SHORTWAVE TRACKS THROUGH THE CENTRAL GREAT LAKES...WITH AN INCH OF
TWO OF SNOWFALL ACCUMULATION POSSIBLE. A SUBTLE BUT NOTICEABLE
WARMING IN THE LOW LEVELS SHOULD CAUSE LOW TEMPERATURES TO OCCUR
EARLY MONDAY NIGHT...WITH SLOWLY RISING TEMPERATURES AFTER MIDNIGHT.
ANOTHER SHORTWAVE TRACKING THROUGH THE SOUTHERN GREAT LAKES ON
TUESDAY COULD BRING ADDITIONAL SNOWFALL AMOUNTS OF A FEW TENTHS OF
AN INCH TO SOUTHEAST MICHIGAN.
ONCE THIS SYSTEM MOVES OFF TO THE EAST HEIGHTS WILL INCREASE ACROSS
THE CENTRAL GREAT LAKES WITH TEMPERATURES WARMING INTO THE 30S ON
THURSDAY...WITH 40S POSSIBLE BY FRIDAY AHEAD OF THE NEXT LOW
PRESSURE SYSTEM TRACKING THROUGH THE GREAT LAKES REGION. THIS
SYSTEM...ORIGINATING OVER THE SOUTHERN PLAINS ON THURSDAY...WILL
TRACK NORTHEAST THROUGH MICHIGAN ON FRIDAY. GIVEN THE NORTHERN TRACK
OF THE LOW THE AREA WILL BE IN THE WARM SECTOR OF THE
SYSTEM...MEANING PRECIPITATION MORE IN THE FORM OF LIQUID RATHER
THAN ICE CRYSTALS. THERE ARE STILL TIMING DIFFERENCES BETWEEN THE
LONG RANGE MODELS...NOTABLY THE FASTER ECMWF AND THE SLOWER GFS.
HOWEVER THEY DO AGREE ON A RETURN TO COLDER TEMPERATURES BEHIND THE
LOW BY SATURDAY AS RIDGING BUILDS OVER THE CENTRAL GREAT LAKES.
MARINE...
WAVES IN THE NEARSHORE ZONES CONTINUE TO SUBSIDE...WITH CONDITIONS
HAVING FALLEN BELOW HEADLINE CRITERIA. HOWEVER...INCREASING WESTERLY
WINDS THIS AFTERNOON ARE EXPECTED AS LOW PRESSURE TRACKS THROUGH THE
CENTRAL GREAT LAKES. THE FETCH WILL BE FAVORABLE FOR WAVES TO BUILD
UP OVER THE NORTHERN TIP OF THE THUMB OVERNIGHT...NECESSITATING A
SMALL CRAFT ADVISORY FOR OUTER SAGINAW BAY AND THE LAKE HURON
NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH. CONDITIONS WILL
REMAIN UNSETTLED INTO EARLY NEXT WEEK AS SOUTHWEST WINDS DEVELOP
AHEAD OF A PASSING SYSTEM MONDAY NIGHT INTO TUESDAY. THERE ARE NO
SIGNIFICANT WIND EVENTS ON THE HORIZON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...FROM 7 PM SUNDAY TO 10 AM
MONDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......SF
AVIATION.....DRK
SHORT TERM...DRK
LONG TERM....KURIMSKI
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
559 AM EST SUN DEC 15 2013
.AVIATION...
//DISCUSSION...
CONDITIONS SHOULD STAY MVFR THROUGH THE DAY FOR CIGS WITH POTENTIAL
FOR NON VFR VSBYS THIS AFTERNOON AS COVERAGE OF SNOW SHOWERS
INCREASES. WESTERLY WINDS WILL INCREASE AS DEEPER MIXING OCCURS THIS
AFTERNOON WITH GUSTS UP TO 25 KNOTS POSSIBLE. MODELS STILL TRYING TO
SCATTER OUT CLOUDS...AND POSSIBLY BECOME CLEAR OVERNIGHT.
FOR DTW...LIGHT SNOW SHOWERS WILL POSSIBLY OCCUR THIS AFTERNOON AS
LAKE EFFECT SNOW EXTENDS EASTWARD ACROSS LOWER MI. WESTERLY WINDS
WILL INCREASE THROUGH THE MORNING WITH GUSTS LIKELY ECLIPSING 25KTS
THIS AFTERNOON OUT OF ABOUT 270-280 DEGREES.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5KFT FT THROUGH THIS EVENING.
* MODERATE CONFIDENCE IN WESTERLY GUSTS EXCEEDING 25KTS SUNDAY
AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 357 AM EST SUN DEC 15 2013
SHORT TERM...TODAY AND TONIGHT
THE SHORT TERM WILL FEATURE LIGHT SNOW...GUSTY AFTERNOON WINDS...AND
POSSIBLE SINGLE DIGIT TEMPS OVERNIGHT. A NORTHERN STREAM UPPER LEVEL
LOW WILL DROP THROUGH THE NORTHERN GREAT LAKES TODAY WHILE A LAKE
AGGREGATE SURFACE TROUGH LINGERS ACROSS CENTRAL MI. STRONG CAA HAS
BEGUN IN THE WAKE OF SATURDAYS LOW AS BROAD MID LEVEL TROUGHING
SINKS INTO THE GREAT LAKES. THIS WILL USHER IN ANOTHER ARCTIC
AIRMASS TO DEAL WITH THROUGH TONIGHT. MODELS SHOW SOME AIRMASS
MODIFICATION AS IT CROSSES THE LAKES WITH -26C TEMPS AT 850MB
ENTERING LAKE SUPERIOR AND NEGATIVE TEENS ENTERING MI. SOUTHERN MI
WILL FALL NEAR THE BASE OF THE MID LEVEL TROUGH AND ON THE SOUTH
SIDE OF THE SFC TROUGH LEADING TO WESTERLY FLOW. THE WESTERLY FLOW
AND CAA WILL LEAD TO AN ACTIVE SETUP FOR LAKE EFFECT WITH MIXING
LEVELS OVER LAKE MI REACHING 10KFT. EVEN OVER SE MI THE CAA IN THE
LOW LEVELS WILL LEAD TO STRONG LAPSE RATES UP TO ABOUT 6KFT. BOTH
THE NAM AND RUC SHOW THE ENTIRE MIXED LAYER TO BE SATURATED WHICH
EXTENDS THROUGH THE DGZ. IN ADDITION TO THE SFC FEATURES...A MID
LEVEL VORT MAX WILL ROTATE AROUND AND THROUGH MID MI LENDING SOME
ADDITIONAL SYNOPTIC SUPPORT ALOFT. POPS WILL RAMP UP IN THE
AFTERNOON AS THE DIURNAL CYCLE GIVES THE MIXED LAYER A BOOST AND AS
THE SFC TROUGH AND VORT MAX SWING THROUGH. LAKE EFFECT SHOULD MAKE
IT INTO THE CWA WITH THE STEADY WESTERLY FLOW DURING THE DAY. THE
NAM IS ADVERTISING THE LAKE MI CONVERGENT BAND SETTING UP WHICH WILL
NEED TO BE WATCHED IN CASE IT IMPACTS ANY ONE AREA FOR ANY
DURATION...MOST LIKELY NEAR THE I94 CORRIDOR. OVERALL NOT EXPECTING
MUCH SNOW WITH AROUND A HALF INCH FOR MOST LOCATIONS. IF WE CAN GET
SOME ENHANCE MESOSCALE FEATURES TO SET UP OR THE LAKE EFFECT BAND TO
PERSIST...TOTALS WOULD OBVIOUSLY GO UP SOME. THE OTHER CONCERN TODAY
WILL BE THE WINDS. MODEL SOUNDINGS SHOW THE MIXING LEVELS PREVIOUSLY
MENTIONED BRINGING DOWN GUST AROUND 30 MPH IN THE AFTERNOON. THIS
WILL LIKELY LEAD TO ADDITIONAL DRIFTING OF THE SNOW PACK. THE LAST
CONCERN WILL BE LOW TEMPS TONIGHT. WITH THE FRESH SNOW PACK AND
ARCTIC AIR MOVING IN...THE POTENTIAL IS THERE FOR LOW SINGLE DIGIT
TEMPS. A BIG CONCERN WILL BE CLOUD COVER PREVENTING THIS FROM
ACTUALLY OCCURRING...ESPECIALLY ACROSS THE SOUTH WHERE THE LAKE
CLOUD SHOULD PERSIST THE LONGEST. ADJUSTED TEMPS UP A COUPLE DEGREES
ACROSS THE SOUTH WITH THE MORE PESSIMISTIC CLOUD COVER
FORECAST...OTHERWISE CONTINUED THE COOL PLAY IN THE MID SINGLE
DIGITS RESULTING IN WIND CHILL VALUES -5 TO -10F.
LONG TERM...MONDAY THROUGH SATURDAY
SHORTWAVE RIDGING WILL TRACK THROUGH THE CENTRAL GREAT LAKES MONDAY
MORNING...KEEPING THE WEATHER DRY FOR THE FIRST HALF OF THE DAY.
QUICKLY ON ITS HEELS WILL BE A VIGOROUS MID LEVEL SHORTWAVE DIVING
SOUTH FROM CANADA. THIS ELONGATED MID LEVEL TROUGH...SEEN ON WATER
VAPOR OVER WESTERN CANADA...WILL BRING A PROLONGED PERIOD OF LIGHT
SNOW SHOWERS FROM MONDAY AFTERNOON THROUGH TUESDAY TO SOUTHEAST
MICHIGAN. AS THE TROUGH MOVES THROUGH THE GREAT LAKES...IT WILL HAVE
THE ASSISTANCE OF BEING UNDER THE LEFT EXIT REGION OF A 140 KNOT JET
DIVING INTO THE WESTERN GREAT LAKES REGION. THE BEST TIME FOR SNOW
APPEARS TO BE LATE MONDAY AFTERNOON INTO MONDAY NIGHT WHEN THE LEAD
SHORTWAVE TRACKS THROUGH THE CENTRAL GREAT LAKES...WITH AN INCH OF
TWO OF SNOWFALL ACCUMULATION POSSIBLE. A SUBTLE BUT NOTICEABLE
WARMING IN THE LOW LEVELS SHOULD CAUSE LOW TEMPERATURES TO OCCUR
EARLY MONDAY NIGHT...WITH SLOWLY RISING TEMPERATURES AFTER MIDNIGHT.
ANOTHER SHORTWAVE TRACKING THROUGH THE SOUTHERN GREAT LAKES ON
TUESDAY COULD BRING ADDITIONAL SNOWFALL AMOUNTS OF A FEW TENTHS OF
AN INCH TO SOUTHEAST MICHIGAN.
ONCE THIS SYSTEM MOVES OFF TO THE EAST HEIGHTS WILL INCREASE ACROSS
THE CENTRAL GREAT LAKES WITH TEMPERATURES WARMING INTO THE 30S ON
THURSDAY...WITH 40S POSSIBLE BY FRIDAY AHEAD OF THE NEXT LOW
PRESSURE SYSTEM TRACKING THROUGH THE GREAT LAKES REGION. THIS
SYSTEM...ORIGINATING OVER THE SOUTHERN PLAINS ON THURSDAY...WILL
TRACK NORTHEAST THROUGH MICHIGAN ON FRIDAY. GIVEN THE NORTHERN TRACK
OF THE LOW THE AREA WILL BE IN THE WARM SECTOR OF THE
SYSTEM...MEANING PRECIPITATION MORE IN THE FORM OF LIQUID RATHER
THAN ICE CRYSTALS. THERE ARE STILL TIMING DIFFERENCES BETWEEN THE
LONG RANGE MODELS...NOTABLY THE FASTER ECMWF AND THE SLOWER GFS.
HOWEVER THEY DO AGREE ON A RETURN TO COLDER TEMPERATURES BEHIND THE
LOW BY SATURDAY AS RIDGING BUILDS OVER THE CENTRAL GREAT LAKES.
MARINE...
WAVES IN THE NEARSHORE ZONES CONTINUE TO SUBSIDE...WITH CONDITIONS
HAVING FALLEN BELOW HEADLINE CRITERIA. HOWEVER...INCREASING WESTERLY
WINDS THIS AFTERNOON ARE EXPECTED AS LOW PRESSURE TRACKS THROUGH THE
CENTRAL GREAT LAKES. THE FETCH WILL BE FAVORABLE FOR WAVES TO BUILD
UP OVER THE NORTHERN TIP OF THE THUMB OVERNIGHT...NECESSITATING A
SMALL CRAFT ADVISORY FOR OUTER SAGINAW BAY AND THE LAKE HURON
NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH. CONDITIONS WILL
REMAIN UNSETTLED INTO EARLY NEXT WEEK AS SOUTHWEST WINDS DEVELOP
AHEAD OF A PASSING SYSTEM MONDAY NIGHT INTO TUESDAY. THERE ARE NO
SIGNIFICANT WIND EVENTS ON THE HORIZON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...FROM 7 PM SUNDAY TO 10 AM
MONDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....DRK
SHORT TERM...DRK
LONG TERM....KURIMSKI
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
357 AM EST SUN DEC 15 2013
.SHORT TERM...TODAY AND TONIGHT
THE SHORT TERM WILL FEATURE LIGHT SNOW...GUSTY AFTERNOON WINDS...AND
POSSIBLE SINGLE DIGIT TEMPS OVERNIGHT. A NORTHERN STREAM UPPER LEVEL
LOW WILL DROP THROUGH THE NORTHERN GREAT LAKES TODAY WHILE A LAKE
AGGREGATE SURFACE TROUGH LINGERS ACROSS CENTRAL MI. STRONG CAA HAS
BEGUN IN THE WAKE OF SATURDAYS LOW AS BROAD MID LEVEL TROUGHING
SINKS INTO THE GREAT LAKES. THIS WILL USHER IN ANOTHER ARCTIC
AIRMASS TO DEAL WITH THROUGH TONIGHT. MODELS SHOW SOME AIRMASS
MODIFICATION AS IT CROSSES THE LAKES WITH -26C TEMPS AT 850MB
ENTERING LAKE SUPERIOR AND NEGATIVE TEENS ENTERING MI. SOUTHERN MI
WILL FALL NEAR THE BASE OF THE MID LEVEL TROUGH AND ON THE SOUTH
SIDE OF THE SFC TROUGH LEADING TO WESTERLY FLOW. THE WESTERLY FLOW
AND CAA WILL LEAD TO AN ACTIVE SETUP FOR LAKE EFFECT WITH MIXING
LEVELS OVER LAKE MI REACHING 10KFT. EVEN OVER SE MI THE CAA IN THE
LOW LEVELS WILL LEAD TO STRONG LAPSE RATES UP TO ABOUT 6KFT. BOTH
THE NAM AND RUC SHOW THE ENTIRE MIXED LAYER TO BE SATURATED WHICH
EXTENDS THROUGH THE DGZ. IN ADDITION TO THE SFC FEATURES...A MID
LEVEL VORT MAX WILL ROTATE AROUND AND THROUGH MID MI LENDING SOME
ADDITIONAL SYNOPTIC SUPPORT ALOFT. POPS WILL RAMP UP IN THE
AFTERNOON AS THE DIURNAL CYCLE GIVES THE MIXED LAYER A BOOST AND AS
THE SFC TROUGH AND VORT MAX SWING THROUGH. LAKE EFFECT SHOULD MAKE
IT INTO THE CWA WITH THE STEADY WESTERLY FLOW DURING THE DAY. THE
NAM IS ADVERTISING THE LAKE MI CONVERGENT BAND SETTING UP WHICH WILL
NEED TO BE WATCHED IN CASE IT IMPACTS ANY ONE AREA FOR ANY
DURATION...MOST LIKELY NEAR THE I94 CORRIDOR. OVERALL NOT EXPECTING
MUCH SNOW WITH AROUND A HALF INCH FOR MOST LOCATIONS. IF WE CAN GET
SOME ENHANCE MESOSCALE FEATURES TO SET UP OR THE LAKE EFFECT BAND TO
PERSIST...TOTALS WOULD OBVIOUSLY GO UP SOME. THE OTHER CONCERN TODAY
WILL BE THE WINDS. MODEL SOUNDINGS SHOW THE MIXING LEVELS PREVIOUSLY
MENTIONED BRINGING DOWN GUST AROUND 30 MPH IN THE AFTERNOON. THIS
WILL LIKELY LEAD TO ADDITIONAL DRIFTING OF THE SNOW PACK. THE LAST
CONCERN WILL BE LOW TEMPS TONIGHT. WITH THE FRESH SNOW PACK AND
ARCTIC AIR MOVING IN...THE POTENTIAL IS THERE FOR LOW SINGLE DIGIT
TEMPS. A BIG CONCERN WILL BE CLOUD COVER PREVENTING THIS FROM
ACTUALLY OCCURRING...ESPECIALLY ACROSS THE SOUTH WHERE THE LAKE
CLOUD SHOULD PERSIST THE LONGEST. ADJUSTED TEMPS UP A COUPLE DEGREES
ACROSS THE SOUTH WITH THE MORE PESSIMISTIC CLOUD COVER
FORECAST...OTHERWISE CONTINUED THE COOL PLAY IN THE MID SINGLE
DIGITS RESULTING IN WIND CHILL VALUES -5 TO -10F.
&&
.LONG TERM...MONDAY THROUGH SATURDAY
SHORTWAVE RIDGING WILL TRACK THROUGH THE CENTRAL GREAT LAKES MONDAY
MORNING...KEEPING THE WEATHER DRY FOR THE FIRST HALF OF THE DAY.
QUICKLY ON ITS HEELS WILL BE A VIGOROUS MID LEVEL SHORTWAVE DIVING
SOUTH FROM CANADA. THIS ELONGATED MID LEVEL TROUGH...SEEN ON WATER
VAPOR OVER WESTERN CANADA...WILL BRING A PROLONGED PERIOD OF LIGHT
SNOW SHOWERS FROM MONDAY AFTERNOON THROUGH TUESDAY TO SOUTHEAST
MICHIGAN. AS THE TROUGH MOVES THROUGH THE GREAT LAKES...IT WILL HAVE
THE ASSISTANCE OF BEING UNDER THE LEFT EXIT REGION OF A 140 KNOT JET
DIVING INTO THE WESTERN GREAT LAKES REGION. THE BEST TIME FOR SNOW
APPEARS TO BE LATE MONDAY AFTERNOON INTO MONDAY NIGHT WHEN THE LEAD
SHORTWAVE TRACKS THROUGH THE CENTRAL GREAT LAKES...WITH AN INCH OF
TWO OF SNOWFALL ACCUMULATION POSSIBLE. A SUBTLE BUT NOTICEABLE
WARMING IN THE LOW LEVELS SHOULD CAUSE LOW TEMPERATURES TO OCCUR
EARLY MONDAY NIGHT...WITH SLOWLY RISING TEMPERATURES AFTER MIDNIGHT.
ANOTHER SHORTWAVE TRACKING THROUGH THE SOUTHERN GREAT LAKES ON
TUESDAY COULD BRING ADDITIONAL SNOWFALL AMOUNTS OF A FEW TENTHS OF
AN INCH TO SOUTHEAST MICHIGAN.
ONCE THIS SYSTEM MOVES OFF TO THE EAST HEIGHTS WILL INCREASE ACROSS
THE CENTRAL GREAT LAKES WITH TEMPERATURES WARMING INTO THE 30S ON
THURSDAY...WITH 40S POSSIBLE BY FRIDAY AHEAD OF THE NEXT LOW
PRESSURE SYSTEM TRACKING THROUGH THE GREAT LAKES REGION. THIS
SYSTEM...ORIGINATING OVER THE SOUTHERN PLAINS ON THURSDAY...WILL
TRACK NORTHEAST THROUGH MICHIGAN ON FRIDAY. GIVEN THE NORTHERN TRACK
OF THE LOW THE AREA WILL BE IN THE WARM SECTOR OF THE
SYSTEM...MEANING PRECIPITATION MORE IN THE FORM OF LIQUID RATHER
THAN ICE CRYSTALS. THERE ARE STILL TIMING DIFFERENCES BETWEEN THE
LONG RANGE MODELS...NOTABLY THE FASTER ECMWF AND THE SLOWER GFS.
HOWEVER THEY DO AGREE ON A RETURN TO COLDER TEMPERATURES BEHIND THE
LOW BY SATURDAY AS RIDGING BUILDS OVER THE CENTRAL GREAT LAKES.
&&
.MARINE...
WAVES IN THE NEARSHORE ZONES CONTINUE TO SUBSIDE...WITH CONDITIONS
HAVING FALLEN BELOW HEADLINE CRITERIA. HOWEVER...INCREASING WESTERLY
WINDS THIS AFTERNOON ARE EXPECTED AS LOW PRESSURE TRACKS THROUGH THE
CENTRAL GREAT LAKES. THE FETCH WILL BE FAVORABLE FOR WAVES TO BUILD
UP OVER THE NORTHERN TIP OF THE THUMB OVERNIGHT...NECESSITATING A
SMALL CRAFT ADVISORY FOR OUTER SAGINAW BAY AND THE LAKE HURON
NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH. CONDITIONS WILL
REMAIN UNSETTLED INTO EARLY NEXT WEEK AS SOUTHWEST WINDS DEVELOP
AHEAD OF A PASSING SYSTEM MONDAY NIGHT INTO TUESDAY. THERE ARE NO
SIGNIFICANT WIND EVENTS ON THE HORIZON.
&&
.AVIATION...ISSUED 1202 AM EST SUN DEC 15 2013
//DISCUSSION...
CEILINGS WILL VARY SIGNIFICANTLY OVERNIGHT AS POCKETS OF DRY AIR
INFILTRATE THE LOWER REACHES OF THE ATMOSPHERE. WINDS WILL BACK
THROUGH NORTHWESTERLY TO WESTERLY BY SUNDAY AM. AS THE BOUNDARY
DESTABILIZES DURING SUNDAY AFTERNOON WEST WINDS WILL BECOME RATHER
GUSTY.
FOR DTW...CEILINGS BE QUITE VARIABLE AS POCKETS OF DRY AIR WORK IN
FROM THE WEST/SOUTHWEST. GUIDANCE CONTINUES TO SUGGEST A NEAR
SURFACE INVERSION DEVELOPING THAT MAY TRAP SOME RESIDUAL MOISTURE
BELOW 1KFT. OTHERWISE...THE OTHER POINT OF INTEREST IS WESTERLY
GUSTS LIKELY ECLIPSING 25KTS SUNDAY AFTERNOON.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5KFT FT THROUGH THE TAF PERIOD.
* LOW CONFIDENCE IN CEILINGS BELOW 1KFT OVERNIGHT.
* MODERATE CONFIDENCE IN WESTERLY GUSTS EXCEEDING 25KTS SUNDAY
AFTERNOON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE
WATERS FROM PORT AUSTIN TO HARBOR BEACH...FROM 7 PM SUNDAY TO
10 AM MONDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...DRK
LONG TERM....KURIMSKI
MARINE.......KURIMSKI
AVIATION.....MANN
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1054 PM CST SAT DEC 14 2013
.UPDATE...FOR 06Z AVIATION DISCUSSION BELOW
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 338 PM CST SAT DEC 14 2013
LIGHT SNOW CONTINUED ACROSS THE REGION TODAY AHEAD OF A WEAK
SHORTWAVE THAT WAS EMBEDDED IN THE PERSISTENT NORTHWEST FLOW.
FORECAST SOUNDINGS OFF THE RAP SHOWED A BEAUTIFUL VEERING
PROFILE...WITH DENDRITIC SATURATION FROM THE SURFACE UP TO 650MB.
THE REGION OF ASCENT ROOTED IN THE POSITIVE VORTICITY ADVECTION
ASSOCIATED WITH THE CURVATURE OF THIS WAVE WILL CONTINUE TO SHIFT
EASTWARD OVERNIGHT. MODEST H500 HEIGHT RISES AND AN ASSOCIATED
SURFACE RIDGE OF HIGH PRESSURE WILL BUILD OVER WESTERN MN...WHICH
WILL SET THE STAGE FOR ANOTHER NIGHT OF COLD TEMPERATURES WITH LIGHT
WINDS...ESPECIALLY IF SKIES MANAGE TO CLEAR. HOWEVER...DESPITE THE
SURFACE HIGH...CONFIDENCE IN CLEARING SKIES IS LOW AS AGITATED
NORTHWEST FLOW WILL CONTINUE. THE THERMAL PROFILE FROM FORECAST
SOUNDINGS ARE SUCH THAT ONLY A SMALL AMOUNT OF UPWARD VERTICAL
MOTION IS REQUIRED TO PRODUCE A FEW SNOWFLAKES...LET ALONE MID LEVEL
CLOUDS. IN FACT...THE NEXT UPPER LEVEL WAVE / LOW LEVEL WARM AIR
ADVECTION DUO WILL MOVE ACROSS WESTERN MN ON SUNDAY...SO HAVE
INCREASED POPS CONSIDERABLY SINCE CONFIDENCE IS HIGH IN ANOTHER
ROUND OF LIGHT SNOWFALL ALONG THE MINNESOTA RIVER VALLEY. SUNDAYS
HIGH TEMPERATURES WILL STRUGGLE TO GET OUT OF THE SINGLE DIGITS FOR
MOST LOCATIONS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 338 PM CST SAT DEC 14 2013
THE UPPER WAVE BRINGING LIGHT SNOW SUNDAY WILL SLIDE SOUTHEAST
INTO THE OHIO VALLEY SUNDAY NIGHT WHILE ANOTHER WAVE DIVES
SOUTHEAST INTO NORTHERN MINNESOTA EARLY MONDAY MORNING. A QUICK
SHOT OF DECENT ISENTROPIC UPGLIDE AND MODEST MOISTURE ADVECTION
WILL BE ENOUGH TO GENERATE A BAND OF SNOW ACROSS NORTHERN AND
CENTRAL MN WHICH WILL PROPAGATE INTO WESTERN WISCONSIN MONDAY
MORNING. ONE TO TWO INCHES OF SNOW ARE POSSIBLE BEFORE STRONG
ISENTROPIC DOWNGLIDE TAKES OVER AGAIN IN THE AFTERNOON AND MONDAY
NIGHT.
A TROUGH DIGGING INTO THE GREAT LAKES WILL CLIP THE FORECAST
AREA...LEAVING WESTERLY SURFACE FLOW IN PLACE THROUGH MIDWEEK.
MILD TEMPS /COMPARED TO THE REST OF THIS MONTH/ CAN BE
EXPECTED...ALTHOUGH TUESDAY NIGHT WILL BE COLD AS THE RIDGE
AXIS PASSES OVERHEAD.
EYES THEN TURN TO LATE WEEK AS A TROUGH DIGS DOWN THE WEST COAST
AND HIGH PRESSURE BUILDS SOUTHWARD INTO WESTERN AND CENTRAL
CANADA. FAST ZONAL FLOW WILL DEVELOP ALONG THE U.S./CANADIAN
BORDER WEDNESDAY WITH ONE WAVE RAPIDLY PUSHING EAST ACROSS
NORTHERN MINNESOTA. SENSIBLE WEATHER IMPACTS FOR OUR AREA WILL BE
MINIMAL INITIALLY WITH FORCING AND MOISTURE CONVERGENCE REMAINING
WELL NORTH. HOWEVER...THIS WAVE AND HIGH PRESSURE BUILDING TOWARD
THE NORTHERN PLAINS WILL PUSH A COLD FRONT SOUTH WEDNESDAY NIGHT.
AS SOME ENERGY ROUNDS THE BASE OF THE WESTERN TROUGH...A SURFACE
LOW WILL SPAWN OVER COLORADO THURSDAY AND TRACK EAST NORTHEAST
ACROSS THE PLAINS AND INTO THE LOWER GREAT LAKES LATE
THURSDAY/THURSDAY NIGHT. NORMALLY THIS WOULD BE A HIGHLY FAVORABLE
TRACK FOR HEAVY SNOWFALL ACROSS THE CWA. HOWEVER...GIVEN THE FAST
FLOW WITH TIGHTENING BAROCLINICITY LEADING TO A MORE PROGRESSIVE
FEATURE...IN CONJUNCTION WITH SURFACE RIDGING OVER THE GULF WHICH
WILL LIKELY DELAY THE NORTHERLY MOISTURE TRANSPORT UNTIL THE
SURFACE WAVE IS TO THE EAST OF THE AREA...WOULD LIMIT THE
POTENTIAL FOR A BIG SNOWFALL. IF MODELS EVOLVE THE WESTERN TROUGH
DIFFERENTLY...AND THEY MOST LIKELY WILL AT THIS RANGE...THIS
FORECAST CAN CERTAINLY CHANGE. LEFT POPS IN THE MID RANGE FOR NOW
WITH THE MOISTURE UNCERTAINTY AND SOME TIMING DIFFERENCES BETWEEN
THE MEDIUM RANGE MODELS.
THE HIGH WILL BUILD IN FOR FRIDAY AND SATURDAY WITH ANOTHER BLAST
OF ARCTIC AIR ACCOMPANYING IT. HIGHS WILL AGAIN BE IN THE SINGLE
DIGITS WITH LOWS FRIDAY NIGHT IN THE TEENS TO 20S BELOW ZERO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1055 PM CST SAT DEC 14 2013
MID LEVEL CLOUDS WILL BE ON THE INCREASE OVERNIGHT...WITH BKN-
OVC CIGS BUILDING IN FROM THE DAKOTAS. ANOTHER AREA OF SNOW WILL
APPROACH WESTERN MN FROM THE DAKOTAS ON SUNDAY...POSSIBLY
AFFECTING KAXN AND KRWF LATE SUNDAY MORNING AND AFTERNOON...BUT
IT/S EXPECTED TO STAY WEST/SOUTH OF THE REMAINDER OF THE TAF
SITES. NORTHWEST WINDS BELOW 10KTS THROUGH MIDDAY SUNDAY...BECOME
LIGHT AND VARIABLE OR LIGHT SOUTHERLY AROUND 00Z MONDAY.
KMSP...
A FEW CLOUDS AROUND 2000-2500FT LINGERS THROUGH SUNDAY...WITH A
BKN-OVC MID LEVEL DECK FOR MUCH OF THE PERIOD AS WELL. 300-330
DEGREE WINDS THROUGH SUNDAY AFTERNOON AT SPEEDS AOB
10KTS...BECOMING LIGHT AND VRB BY 00Z MONDAY.
/OUTLOOK FOR KMSP/
MON...VFR/MVFR WITH IFR/-SN POSSIBLE. WINDS SW AT 10KTS.
TUE...VFR WITH MVFR/-SN POSSIBLE. WINDS W AT 15KTS.
WED...VFR. WINDS VRBL AT 05KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...BORGHOFF
AVIATION...LS
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
308 PM CST Sun Dec 15 2013
.SHORT TERM: (Tonight through Monday)
Issued at 259 PM CST Sun Dec 15 2013
Lots of caveats to the forecast for tonight leading to low confidence
in some of the details. A strong surface front currently extends
from western SD through central NE and northeast KS across northern
MO into west central IL. The models are in decent agreement that a
surface low pressure wave will track southeastward along the front
from the central Plains into southern IL tonight with the front
sagging southward in its wake. This surface low will be in response
to a weak elongated short wave/vort max migrating southeastward
within the NW flow aloft. The large scale forcing and strongest
low level baroclinity/frontogenesis will reside to the north of
the forecast area from Iowa thru north central IL into southeast
IN and this is where the greatest threat of snow should reside.
Along the far southern periphery of this zone which encompasses a
zone from around Edina to Quincy to White Hall to Nokomis, the RAP
suggests there could be a brief shot of decent ascent. It also has
some very light QPF within this zone and the last few available
runs of the HRRR showed some spotty precipitation. The overall low
level flow regime is characterized south of the aforementioned
front and above the boundary layer by warm air advection. This WAA
while also contributing to lift has warmed the atmosphere and
soundings suggest any precipitation could teeter between light
freezing rain or light snow. I have added some low pops to account
for this probability and it will bear close watching on the
evening shift. Further south snow melt has contributed to low
level moistening and some of the guidance suggests fog and stratus
will develop. The 12z run of the NAM even went as far as developing
freezing drizzle. The boundary layer is where all the models have
the poorest time resolving, thus my confidence is limited, but
given the current surface dew points are now close to the forecast
mins I have opted to included a mention of fog in the forecast. If
stratus and fog are widespread on Monday morning, then the trend
should be for this to erode/dissipate as the morning progresses
and weak low level WAA kicks in. If the stratus/fog or clouds are
at a minimum then my forecast highs are likely to cool.
Glass
.LONG TERM: (Monday Night through Next Sunday)
Issued at 259 PM CST Sun Dec 15 2013
Despite another weak and ill-defined cold front passing though the
area on Tuesday, the temperatures should moderate some. The real
moderation however will begin to unfold on Tuesday night as the
surface high retreats and low level WAA gets underway. Strong WAA
will be in full swing on Wednesday as low level flow becomes
south/southwesterly and the upper flow transitions to quasi-zonal.
This should be a big snow melter with highs in the upper 40s-middle
50s.
The extended portion of the forecast, especially towards the
weekend, is marked by considerable uncertainty. A big pattern change
will continue to evolve with considerable amplification from the
central Pacific across the CONUS. The main feature will be the
development of a split flow regime with a deep long wave positively
tilted trof in the western U.S. and upper low in the southwest. This trof
develops in response to the absorption of an upper low currently in
the southeast Pacific near 27N/134W and short waves digging
southward out of the Gulf of AK along the west coast. The northern
stream will serve to bring a cold front through the area Thursday
night/early Friday accompanied by a chance of rain and possibly some
rain/snow mix in the wake. However the northern stream is sharper on
the GFS and it also leaves the upper low spinning in the vicinity of
northern Baja CA. This solution would suggest limited post-frontal
precipitation with high pressure building into the Mid MS Valley
late Friday and then additional waves in the northern stream
reinforcing the high pressure and essentially keeping precipitation
south of the area. Alternatively the ECMWF develops an overunning
scenario Saturday into Sunday and potential for a winter mess.
There is no scientific basis at this point in time to suggest one
solution is vastly better than another and the models will continue
to change multiple times in the details in the coming week. Given
the forecast large scale pattern changes and vastly differing model
solutions and resultant low confidence, the best approach at this
time is more of an ensemblistic approach with some mixed flavor.
Glass
&&
.AVIATION: (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1221 PM CST Sun Dec 15 2013
Surface ridge to continue weakening as shortwaves slide southeast
through region. Will mainly just see an increase in clouds with
each shortwave, though could have some light snow/flurries for
tafs along Mississippi river valley. For now only mention light
snow in KUIN after 02z Monday as they are closer to better dynamics.
Otherwise, will see mvfr cigs sliding into region late this
afternoon and early this evening. The low cigs to persist through
remainder of forecast period. Some question as to how low cigs
will go as well as fog development due to some melting of the snow
pack today. For now keep mvfr vsbys at KCOU and metro area tafs
tonight until we get a better grasp possible fog situation. Winds
to become light and variable as clipper system moves through, then
winds pick back up from the west to northwest on Monday morning.
Specifics for KSTL:
Surface ridge to continue weakening as shortwaves slide southeast
through region. Will mainly just see an increase in clouds with
each shortwave, though could have some light snow/flurries for
tafs along Mississippi river valley. For now kept mention out of
KSTL taf. Otherwise, will see mvfr cigs sliding into metro area
after 03z Monday and persist through remainder of forecast period.
Some question as to how low cigs will go as well as fog
development due to some melting of the snow pack today. For now
keep mvfr vsbys at KSTL tonight until we get a better grasp
possible fog situation. Winds to become light and variable as
clipper system moves through, then winds pick back up from the
west by 17z Monday.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
859 PM MST MON DEC 16 2013
.UPDATE...
MADE A FEW CHANGES TO THE INHERITED FORECAST THIS
EVENING...CONCENTRATED TO EASTERN PORTION OF THE CWA.
SNOW SHOWERS HAVE CLEARED THE REGION TO THE EAST...DROPPED
MAJORITY OF POPS IN THE AREA...BUT STILL A BIT OF CLOUD COVER IN
PLACE IN THE EAST. DID KEEP SLIGHT CHANCE POPS IN BAKER...AS
SHOWER ACTIVITY IS STILL CLOSE ENOUGH TO CATCH THAT AREA.
TEMPERATURES DROPPED QUICKLY IN MILES CITY WITH CLEARING...SO
REDUCED FORECAST LOWS A COUPLE OF DEGREES AS ARE WITHIN A DEGREE
OF INHERITED LOW. RAISED OVERNIGHT LOW FORECAST SLIGHTLY IN
FORSYTH AND BAKER HOWEVER...IN RESPONSE TO HIGH CURRENT
TEMPS...AND DEWPOINTS.
FINALLY INTRODUCED AREAS OF FOG TO THE AREAS FROM FORSYTH TO
EKALAKA AND NORTH. RAPIDLY COOLING TEMPS IN MILES CITY CAUSED VIS
TO DROP TO 1/4MI. VIS DID COME BACK UP AFTER AN HOUR OR SO...BUT
EXPECT THAT SAME WILL BE POSSIBLE IN THE REST OF THE NORTHEAST
AREAS...AS CLEARING OCCURS. AAG
&&
.SHORT TERM...VALID FOR TUE AND WED...
MILD AND WINDY WEATHER WILL CONTINUE THROUGH WED BENEATH NORTHWEST
FLOW ALOFT...BUT A SHORT WAVE TROUGH WILL THEN SEND AN ARCTIC COLD
FRONT SOUTH THROUGH THE REGION WITH SNOW BEGINNING WED NIGHT.
TONIGHT...WE HAVE LINGERED SOME LIKELY POPS THROUGH THE EVENING IN
THE BAKER AREA...LARGELY BASED ON RECENT RAP SIMULATIONS WHICH ARE
ABOUT THE ONLY GUIDANCE CAPTURING ONGOING SNOW OVER THAT AREA. THE
SNOW /WHICH WE DID NOT EXPECT TO THIS MAGNITUDE/ APPEARS DRIVEN BY
MID-LEVEL FRONTOGENESIS...WHICH SHOULD ONLY SLOWLY WANE DURING THE
LATE AFTERNOON AND EVENING. OTHERWISE...WINDS WILL INCREASE BEFORE
DAYBREAK AGAIN IN THE LIVINGSTON AND NYE AREAS AS SUBSTANTIAL LEE-
SIDE SURFACE PRESSURE FALLS TAKE SHAPE FROM NORTH CENTRAL MT UP TO
CENTRAL ALBERTA. WE THUS BEGAN A WIND ADVISORY AT 09 UTC FOR THOSE
LOCATIONS. FINALLY...WE GENERALLY HELD LOWS A BIT WARMER THAN WHAT
GUIDANCE WOULD SUGGEST IN MOST PLACES TONIGHT SINCE DEWPOINTS THIS
AFTERNOON HAVE MAINLY STAYED IN THE 20S F. OUR CONFIDENCE IS LOWER
THAN NORMAL THOUGH. ONE EXCEPTION TO THIS METHODOLOGY WAS AT BAKER
WHERE FRESH SNOW COULD ALLOW TEMPERATURES TO FALL QUICKLY.
TUE...A STRONG LOW-LEVEL PRESSURE GRADIENT WILL CONTINUE FOR SOUTH
CENTRAL MT AND CONTINUE TO BE AIDED BY ISALLOBARIC FORCING WITH AN
AXIS OF 5 HPA/3 HOUR SURFACE PRESSURE FALLS NORTHEAST OF THE LOCAL
AREA. THE MAGNITUDE OF MID-LEVEL STABILITY AND 700-HPA WIND SPEEDS
OF 50 KT OVER LIVINGSTON BODE WELL FOR ADVISORY-LEVEL WINDS THANKS
TO A 15-20 HPA SURFACE GRADIENT BETWEEN IDAHO FALLS AND LEWISTOWN.
DOWNSTREAM...MID-LEVEL WINDS ARE CLOSER TO 60 KT FOR HARLOWTON AND
BIG TIMBER...AND LOW-LEVEL LAPSE RATES ARE STEEP ENOUGH TO SUPPORT
60 MPH GUSTS IN THOSE AREAS. THUS...WE ISSUED A WIND ADVISORY OVER
NORTHERN SWEET GRASS COUNTY AND A HIGH WIND WATCH ACROSS SOUTHERN
WHEATLAND COUNTY /WHERE WARNING CRITERIA IS LOWER/ BEGINNING AT 13
UTC TUE. AN IN-HOUSE STATISTICAL METHOD FOR HIGH WINDS IN SOUTHERN
WHEATLAND COUNTY ALSO SUPPORTS 60-65 MPH GUSTS AT HARLOWTON. HIGHS
WILL BE MILD AGAIN TUE...WITH 50+ F READINGS IN SOUTH CENTRAL MT.
TUE NIGHT...STRONG WINDS WILL CONTINUE IN SOUTH CENTRAL MT...SO WE
KEPT HEADLINES GOING. A WELL-MIXED BOUNDARY LAYER MAY KEEP LOWS ON
THE WARM SIDE...EVEN ON THE RIDGETOPS OF SOUTHEASTERN MT.
BY WED...THE LOW-LEVEL PRESSURE GRADIENT WILL BE RELAXING...SO THE
WINDS SHOULD BEGIN DECREASING DURING THE MORNING. ANOTHER MILD DAY
IS IN STORE...AND MUCH LIKE PRIOR DAYS IT/S POSSIBLE THAT GUIDANCE
WILL HAVE A COLD BIAS GIVEN THE RAPIDLY MELTING SNOW FIELD. ON WED
NIGHT...WE HAVE HIGH CONFIDENCE IN AN ARCTIC COLD FRONT PUSHING TO
THE SOUTH ACROSS THE AREA...WITH WIDESPREAD SNOW DEVELOPING BEHIND
THE BOUNDARY PER WELL-CLUSTERED 12 UTC MODEL SOLUTIONS. QG FORCING
ALOFT AND LOW-LEVEL UPSLOPE STRONGLY SUPPORTS A FEW INCHES OF SNOW
OVER MUCH OF THE AREA BY DAYBREAK THU. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
SURGE OF ARCTIC AIR THURSDAY MORNING WILL BE CONTINUING TO SUPPORT
SNOWFALL AS A DISTURBANCE SWING THROUGH WESTERN MONTANA. SURFACE
WINDS LOOK TO STAY IN A NORTHEASTERLY ORIENTATION WHICH WILL FAVOR
UPSLOPE EFFECTS AND GENERALLY EXPECT 2 TO 6 INCH SNOWFALL AMOUNTS
ACROSS THE REGION WITH 4 TO 5 INCHES BEING REALLY COMMON. THIS IS
TIMING WITH THE THURSDAY MORNING COMMUTE SO SLICK ROADS AND POOR
VISIBILITY SHOULD BE EXPECTED. SNOW DISSIPATES THURSDAY AFTERNOON
AND EARLY EVENING AS THE ARCTIC HIGH QUICKLY PULLS TO THE
SOUTHEAST AND LEESIDE TROFFING BEGINS ALONG THE FRONT RANGE. THIS
PATTERN MAY CAUSE AN EPISODE OF BLOWING SNOW LATE THURSDAY NIGHT
AND FRIDAY SO WILL HAVE TO WATCH FOR A BIMODAL WINTER THREAT BUT
IT MAY NOT BE CONTINUOUS. TEMPERATURES ON THURSDAY LOOK GO NOWHERE
WITH COLD ADVECTION CONTINUING AND CLOUDS AND SNOW ELIMINATING
HEATING. WILL BE SOME COLD SPOTS THURSDAY NIGHT ACROSS THE EAST
BUT MIXING OVER THE WESTERN ZONES SHOULD LIMIT TEMPERATURES FROM
FALLING BELOW ZERO.
FRIDAY TEMPERATURES ALREADY MODERATING ACROSS THE AREA WITH
WESTERN ZONES TRYING TO APPROACH 30. WINDS WILL BE ON THE INCREASE
FOR GAP FLOW AREAS WITH THIS PATTERN CONTINUING INTO SATURDAY.
FOR SATURDAY AND BEYOND NORTHWEST FLOW ALOFT LOOKS MOIST AND
UNSETTLED WITH A WAFFLING ARCTIC BOUNDARY ACROSS THE REGION.
ANALOGS AND CONFIDENCE TOOLKIT DIAGNOSTICS SHOW IT IS NOT A VERY
WET PATTERN BUT SOME SHOWER ACTIVITY SHOULD BE EXPECTED WITH
MODELS INDICATING A STRONG MOISTURE TAP MOVING INTO THE PACIFIC
NORTHWEST. MODELS ARE ALSO SHOWING A BETTER PUSH OF COLD AIR INTO
SOUTHEAST MONTANA SATURDAY NIGHT AND SUSPECT THAT THIS MAY BE A
RECURRENT THEME THROUGH THE EXTENDED. HAVE ADDED ISOLATED TO
SCATTERED SHOWER ACTIVITY FOR PERIODS SATURDAY AND BEYOND. BORSUM
&&
.AVIATION...
VFR CONDITIONS ACROSS THE REGION...WITH GUSTY WINDS ALONG THE
FOOTHILLS...ESPECIALLY INVOF KLVM. EXPECT WINDS TO BECOME EVEN
STRONGER AFTER MIDNIGHT TONIGHT. AREAS OF FOG ARE POSSIBLE FROM
FORSYTH TO THE EAST AND SOUTHEAST...WITH DENSE FOG ALREADY
REPORTED IN KMLS. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 026/052 033/047 010/014 002/028 017/030 019/039 026/040
00/N 02/R 88/S 12/J 32/J 22/J 22/J
LVM 032/049 034/048 012/016 004/028 019/031 024/037 028/040
00/N 02/R 88/S 22/J 32/J 22/J 22/J
HDN 020/055 029/048 007/014 908/027 009/029 009/038 018/041
00/B 02/R 88/S 11/B 22/J 22/J 22/J
MLS 018/040 026/042 002/008 910/019 002/020 009/031 018/037
10/B 02/R 88/S 11/B 12/J 22/J 22/J
4BQ 019/047 025/048 005/014 908/024 006/025 012/038 021/042
10/B 00/B 58/S 11/B 22/J 22/J 22/J
BHK 019/038 022/039 002/008 908/018 004/019 006/028 019/036
20/B 01/B 78/S 10/B 12/J 22/J 22/J
SHR 023/051 027/050 008/016 906/025 009/029 012/037 018/043
00/B 01/B 58/S 11/B 22/J 22/J 22/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...HIGH WIND WATCH IN EFFECT FROM 6 AM MST TUESDAY THROUGH
WEDNESDAY MORNING FOR ZONE 28.
WIND ADVISORY IN EFFECT FROM 6 AM TUESDAY TO NOON MST
WEDNESDAY FOR ZONE 41.
WIND ADVISORY IN EFFECT FROM 2 AM TUESDAY TO NOON MST
WEDNESDAY FOR ZONES 65-66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1154 AM CST SUN DEC 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST SUN DEC 15 2013
TODAY AND TONIGHT...A POWERFUL THERMAL RIDGE WILL CONTINUE OPERATING
ACROSS THE FORECAST AREA. WINDS AT H850 MB CONTINUE AT 35 TO 45 KT
TODAY AND THEN WEAKEN TO AROUND 30 KTS TONIGHT. THE MID LEVEL CLOUD
DECK CURRENTLY ACROSS THE FCST AREA IS FCST TO SHIFT EAST AND EXIT
THE AREA THIS AFTN. AT THE SAME TIME A BANK OF CIRRUS ACROSS THE NRN
PLAINS WILL DRIFT ACROSS THE FCST AREA. THE TEMPERATURE FCST TODAY
USES THE WARM SIDE OF THE MODEL CONSENSUS PLUS ABOUT 3 DEGREES FOR
HIGHS IN THE UPPER 50S SOUTHWEST TO UPPER 30S NORTHEAST. THIS IS A
FEW DEGREES COOLER THAN THE HRRR MODEL BUT THAT MODEL WAS TOO WARM
SATURDAY.
THE QUESTION TONIGHT IS HOW COOL LOWS WILL GO. PRESUMABLY CIRRUS
WILL CONTINUE ACROSS THE FCST AREA BUT NONE OF THE MODELS SHOW MUCH
MID LEVEL CLOUDINESS WHICH WOULD KEEP MIN TEMPS IN THE 30S. THE FCST
IS FOR LOWER 20S ASSUMING CIRRUS CLOUDS.
OTHERWISE...500M AGL WINDS INCREASE TO 25 TO 30 KTS WHICH SUPPORTS
WINDS IN THE 20 TO 30 MPH RANGE AT THE SFC. THE FCST USES MULTIMODEL
DATA TODAY AND TONIGHT FOR WINDS BUT INCREASES WIND SPEEDS TO NEAR
THE MAV GUIDANCE...THE STRONGEST WIND DATA SET AVAILABLE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 355 AM CST SUN DEC 15 2013
PRIMARY FORECAST PROBLEMS THROUGH THIS PERIOD ARE TEMPERATURES AS
WELL AS PRECIPITATION CHANCES THURSDAY AND THURSDAY NIGHT.
AMPLIFIED UPPER LEVEL FLOW WITH RIDGING OVER THE EASTERN PACIFIC AND
WESTERN CONUS WITH TROUGHING OVER THE EASTERN HALF OF THE CONUS WILL
GIVE WAY TO A CHANGE BY MID WEEK AS THE UPPER LEVEL LOW CURRENTLY
OVER ONTARIO MOVES EAST DECREASING THE STRENGTH OF THE
TROUGH...WHILE A SERIES OF SHORTWAVE TROUGHS MOVE THROUGH THE
NORTHERN STREAM OUT OF RUSSIA AND ALASKA TO FLATTEN THE FLOW BY
MONDAY AND TUESDAY. SEVERAL WEAK SURFACE FRONTS WILL MOVE THROUGH
THE REGION WITH THE FIRST COMING THROUGH MONDAY MORNING AND ANOTHER
MONDAY NIGHT. EVEN WITH THESE FRONTS MOVING THROUGH...THE AIRMASS
WILL HAVE A PACIFIC INFLUENCE SO NOT EXPECTING TEMPERATURES TO BE
IMPACTED MUCH BY IT. WILL ALSO SEE WESTERLY FLOW IN THE LOW LEVELS
TO HELP WITH MIXING AND RAISING THE TEMPERATURES ON MONDAY. HIGH
PRESSURE WILL BUILD SOUTHEAST ACROSS THE AREA AND BY TUESDAY WILL
MOVE FURTHER SOUTHEAST BRINGING RETURN FLOW BACK INTO THE AREA.
AGAIN EXPECTING TEMPERATURES SIMILAR TO SUNDAY AND MONDAY.
TUESDAY NIGHT INTO WEDNESDAY THE CHANGING UPPER LEVEL PATTERN WILL
START TO BECOME APPARENT AS WHAT WILL BECOME A STRONG UPPER LEVEL
WAVE MOVES DOWN THE BRITISH COLUMBIA COAST AND INTO THE PACIFIC
NORTHWEST. MEANWHILE...THE UPPER LOW CURRENTLY WELL OFF THE
CALIFORNIA COAST WILL MOVE ONSHORE INTO SOUTHERN CALIFORNIA. AS
THESE TWO SYSTEMS BEGIN TO DEEPEN A TROUGH OVER THE WEST
COAST...UPPER LEVEL RIDGING WILL BUILD OVER THE PLAINS.
CONCURRENTLY...LOW PRESSURE AT THE SURFACE WILL DEVELOP OVER EASTERN
WYOMING WHICH WILL STRENGTHEN THE SOUTHERLY FLOW INTO THE LOCAL
AREA. WEDNESDAY SHOULD BE THE WARMEST DAY OF THE WEEK...HOWEVER
THERE ARE SOME DIFFERENCES IN HOW WARM IT WILL GET. THE ECMWF RISES
850MB TEMPERATURES TO NEAR 13C OVER THE SOUTHERN PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON...WHILE THE GFS DOESN/T WARM
THINGS UP AS MUCH. THIS WOULD MEAN A DIFFERENCE IN HIGHS BY 5 TO 10
DEGREES ACROSS THE FORECAST AREA. AT THIS TIME...TRENDED CLOSER TO
THE WARMER SOLUTION...YET NOT AS WARM AS SOME MODEL SOLUTIONS
SUGGESTING.
THE OTHER CONSIDERATION WHEN DEALING WITH THE TEMPERATURES IS THE
IMPACT OF THE SNOWPACK OVER THE NORTHERN PARTS OF THE FORECAST AREA.
SHOULD GET QUITE A BIT OF SNOW TO MELT OVER THE NEXT SEVERAL
DAYS...AND DO HAVE TEMPERATURES ON THE UPWARD TREND THROUGH
WEDNESDAY. BELIEVE WILL STILL SEE SOME INFLUENCE FROM THE SNOW
THROUGH THE WEEK...BUT HOW MUCH REMAINS IN QUESTION. WILL SEE HOW
TEMPERATURES WARM TODAY AND WILL SEE WHAT ADJUSTMENTS WILL NEED TO
BE MADE FOR THE FOLLOWING DAYS OVER THE NEXT SEVERAL FORECAST
CYCLES.
ON WEDNESDAY NIGHT THE UPPER LOW THAT MOVES INTO CALIFORNIA ON
WEDNESDAY WILL EJECT OUT OF THE UPPER TROUGH AND INTO THE CENTRAL
PLAINS. AS THIS OCCURS...THE WYOMING SURFACE LOW WILL MOVE INTO
EASTERN COLORADO...WITH THE ENTIRE SYSTEM WEAKENING. GOING INTO
THURSDAY THE SURFACE LOW WILL MOVE ACROSS KANSAS WITH AN INVERTED
TROUGH PASSING ACROSS THE LOCAL FORECAST AREA. THE MAJORITY OF
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL REMAIN ACROSS KANSAS AND
SOUTHEAST NEBRASKA SO NOT EXPECTING ANY PRECIPITATION INVOLVED WITH
IT.
FOCUS THEN TURNS TO THE NEXT ARCTIC AIRMASS TO PUSH THROUGH THE
PLAINS. THE ARCTIC FRONT IS NOW BEING TIMED TO MOVE SOUTH ACROSS
NEBRASKA DURING THE DAY THURSDAY WITH PRECIPITATION MOVING IN BEHIND
THE FRONT. THE MUCH COLDER AIR WILL LAG BEHIND THE FRONT...HOWEVER
WITH COLD AIR ADVECTION ONGOING THROUGH THE DAY AM QUESTIONING HOW
WARM IT WILL GET...OR WHAT TIME HIGHS WILL BE REACHED. LOCATIONS
ACROSS THE NORTH MAY SEE HIGHS IN THE MORNING...WHILE THE SOUTHERN
PARTS OF THE AREA MAY HAVE SOME TIME TO WARM UP BEFORE THE BIG PUSH
OF COLD AIR. DID LOWER HIGHS SLIGHTLY FOR THURSDAY...BUT WILL LIKELY
NEED FURTHER ADJUSTMENTS UNTIL A BETTER HANDLE IS ON THE MODELS FOR
THIS SYSTEM. THE PRESSURE GRADIENT WILL TIGHTEN BEHIND THE
FRONT...WITH STRONG NORTHERLY WINDS EXPECTED ON THURSDAY INTO
THURSDAY NIGHT. BY FRIDAY HIGH PRESSURE WILL BUILD IN WITH THE
PRESSURE GRADIENT RELAXING SO WINDS SHOULDN/T BE AS STRONG. COLDER
AND BELOW NORMAL TEMPERATURES WILL THEN CONTINUE INTO THE WEEKEND AS
THE TROUGH AXIS MOVES ACROSS THE CONUS THROUGH THE WEEKEND. CURRENT
MODELS AREN/T QUITE AS COLD WITH THE TEMPERATURES FOR FRIDAY AND
SATURDAY AS PREVIOUS RUNS...BUT STILL BRING 850MB TEMPERATURES OF
-15C TO -17C INTO THE CENTRAL PLAINS.
IN TERMS OF PRECIPITATION...THERE SEEMS TO BE AN ISSUE WITH A POCKET
OF DRY AIR IN THE MID LEVELS BEHIND THE FRONT WHICH MAY CAUSE
PROBLEMS WITH THE DEVELOPMENT OF PRECIPITATION. THERE CONTINUES TO
BE A SLIGHT SIGNAL FOR SOME DRIZZLE ON THURSDAY PRIOR TO THE COLUMN
BECOMING SATURATED THURSDAY NIGHT. HOWEVER...EVEN IN THE LOW
LEVELS...THE AIR WASN/T COMPLETELY SATURATED EITHER SO WILL STILL
NOT MENTION ANY DRIZZLE YET IN THE FORECAST. BESIDES THIS OUTSIDE
CHANCE FOR DRIZZLE...THE POST-FRONTAL PRECIPITATION SHOULD BE QUITE
LIGHT. PRECIPITABLE WATER AMOUNTS AREN/T BAD...HOWEVER THE SIGNALS
FOR ANY FRONTOGENESIS ARE NOT STRONG AND THE MOISTURE DOES NOT STAY
LONG BEFORE MUCH DRIER AIR PUSHES IN TO DRY OUT THE COLUMN SO NOT
EXPECTING ANY HEAVY PRECIPITATION AMOUNTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1154 AM CST SUN DEC 15 2013
GENERAL VFR EXPECTED ACROSS ALL WESTERN AND NORTH CENTRAL NEBRASKA
AVIATION TERMINALS TODAY/TONIGHT. THERE IS A CONTINUED STREAM OF
MID/HIGH LEVEL CLOUDS THAT HAVE BROUGHT PERIODIC OVC SKIES TO BOTH
KVTN AND KLBF...THIS TREND SHOULD CONTINUE THROUGH THE FORECAST
PERIOD. OTHERWISE WESTERLY SFC WIND WILL BECOME GUSTY THIS
AFTERNOON...ESPECIALLY ACROSS AND SOUTH OF THE CENTRAL
SANDHILLS. PEAK WIND GUSTS OF 24KTS ARE EXPECTED THIS AFTERNOON AT
KLBF....BUT WINDS WILL WEAKEN CONSIDERABLY OVERNIGHT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1123 AM CST SUN DEC 15 2013
.UPDATE...
ISSUED AT 1123 AM CST SUN DEC 15 2013
ANOTHER DAY...ANOTHER TRICKY TEMPERATURE FORECAST. DESPITE QUITE
A BIT OF PASSING MID/HIGH LEVEL CLOUDS SO FAR THIS MORNING...HAVE
BEEN IMPRESSED WITH TEMP RISES...AS ALL BUT THE FAR NORTHEAST CWA
IS ALREADY WELL INTO THE 40S. HOWEVER...THE FAR NORTHEAST IS RIGHT
WITHIN A SHARP GRADIENT ALONG A NORTHWEST-SOUTHEAST ORIENTED QUASI-
STATIONARY FRONT...AS COLUMBUS AIRPORT IS SITTING AT ONLY 25...12
DEGREES COOLER THAN NEARBY YORK. ALTHOUGH NOT QUITE READY TO BUY
WHOLE- SALE INTO THE RAW HOURLY RAP13 TEMPS FOR THIS
AFTERNOON...HAVE RAISED HIGHS AT LEAST 3 DEGREES FROM ORIGINAL
MORNING FORECAST IN ALL AREAS...AND VERY POSSIBLY NOT ENOUGH. AS
IT CURRENTLY STANDS...NOW HAVE THE MAJORITY OF THE CWA TOPPING OUT
50-55...WITH SEVERAL FAR WESTERN/SOUTHERN AREAS MORE SO 56-59. THE
FAR NORTHEAST...ESPECIALLY THE POLK/EASTERN NANCE AREA STANDS THE
BIGGEST ROOM FOR A 5+ DEGREE BUST DEPENDING ON WHETHER OR NOT THE
WARMER AIR CAN SHOVE A LITTLE FARTHER EAST OR NOT. WILL NOT GET
TOO CARRIED AWAY IN THIS AREA...BUT WILL LEAN TOWARD THE
OPTIMISTIC SIDE OF THINGS WITH LOW-MID 40S EVENTUALLY WORKING IN.
OTHERWISE...A FEW ELEVATED RADAR RETURNS ARE SKIRTING FAIRLY CLOSE
TO THE FAR NORTHERN EDGE OF THE CWA...BUT HAVE DOUBTS THAT EVEN A
ROGUE SPRINKLE IS REACHING THE GROUND SO WILL KEEP IT PRECIP-FREE
THIS AFTERNOON UNDER VARIABLE SKY COVER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 433 AM CST SUN DEC 15 2013
THE BIGGEST CHALLENGE WILL BE DETERMINING HIGH TEMPERATURES TODAY.
AT UPPER LEVELS...A RIDGE WILL BE IN THE PACIFIC WHILE A TROUGH IN
THE EASTERN UNITED STATES WILL EXIST. WE WILL BE IN NORTHWEST FLOW
IN BETWEEN WITH WARM AIR ADVECTION BEING ADVERTISED AT 850 MB AS THE
RIDGE NUDGES EAST. A SMALL PERTURBATION UPSTREAM WILL PASS ACROSS
THE CWA THIS MORNING...AND FOR TONIGHT...AN UPPER JET WILL APPROACH
AS THE LEFT FRONT QUADRANT WILL PROBABLY BE NEAR OUR AREA BY THE END
OF THE OVERNIGHT.
AT THE SURFACE...A WARM FRONT HAS NEARLY PASSED THROUGH THE ENTIRE
CWA...EXCEPT FOR THE FAR NORTHEASTERN CORNER. THIS FRONT SHOULD
CONTINUE TO EDGE FARTHER EAST THIS MORNING AND WE SHOULD BE
COMPLETELY IN THE WARM SECTOR FOR TODAY AND TONIGHT...ALTHOUGH THE
COLDER AIR WILL NOT BE TOO FAR TO THE EAST. GOING ABOVE GUIDANCE AS
RECENT BIAS CORRECTED MODEL VERIFICATION SUGGESTS THIS WOULD BE A
GOOD IDEA...AS WELL AS THE FACT THAT OUR SNOW PACK OVER THE CENTRAL
PART OF THE CWA IS FAST DWINDLING. A FLY IN THE OINTMENT COULD BE THE
MID TO UPPER LEVEL CLOUDINESS ASSOCIATED WITH THE PERTURBATION
MOVING ACROSS THE AREA DURING THE LATE MORNING INTO POSSIBLY THE
EARLY AFTERNOON...BUT THE HRRR SUGGESTS THAT WE SHOULD BE WELL CLEAR
OF MOST OF THIS SKY COVER BEFORE THE PEAK HEATING OF THE DAY OCCURS.
ANY PRECIPITATION SHOULD REMAIN WELL OFF THE NORTHEAST AND EAST OF
THE CWA WITH A PASSING WAVE AND NO MODEL IS ADVERTISING MEASURABLE
PRECIPITATION...ALTHOUGH THE WRF IS INDICATING PERHAPS SOME VERY
LIGHT NON-MEASURABLE PRECIPITATION IN OUR FAR NORTHEAST...BUT THIS
IS CLEARLY AN OUTLIER AND NOT CONSIDERED IN THIS FORECAST. THERE
COULD BE A BIT OF PATCHY FOG IN OUR EAST TONIGHT AS THE SREF IS
PICKING UP ON THIS. WITH WIND IN THE EAST NEAR CALM FOR PART OF THE
NIGHT AND DEWPOINT DEPRESSIONS PREDICTED TO BE LOW...WITH A LITTLE
BIT OF FRESHLY MELTED SNOW. THIS SHOULD NOT AMOUNT TO MUCH...AND BY
LATE OVERNIGHT...WIND WILL PROBABLY PICK UP A BIT TO DECREASE FOG
POTENTIAL. WITH THE APPROACHING LEFT FRONT QUADRANT OF AN UPPER
LEVEL JET...WE COULD ALSO HAVE SOME INCREASED CIRRUS BY LATE
OVERNIGHT AS WELL. GOING CLOSE TO GUIDANCE NUMBERS FOR LOWS TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 433 AM CST SUN DEC 15 2013
PRIMARY FORECAST CONCERNS THROUGH THE LONG TERM PERIOD LIE WITH A
CHANGE IN TEMPERATURES LATE IN THE WEEK...AND PRECIPITATION CHANCES.
THERE REALLY HASNT BEEN ANY SIGNIFICANT CHANGES IN THE MODELS
THROUGH THE PERIOD...SHOWING IT STARTING OUT MONDAY MORNING WITH
NORTHWESTERLY FLOW CONTINUING IN THE UPPER LEVELS...SET UP BETWEEN
AN AREA OF LOW PRESSURE OVER THE NERN CONUS...AND A RIDGE AXIS
EXTENDING ALONG WRN PORTIONS OF MEXICO UP INTO THE WEST COAST OF THE
CONUS. AT THE SURFACE...EXPECTING THE CWA TO BE BETWEEN HIGH
PRESSURE OVER THE SRN PLAINS AND LOW PRESSURE OVER CENTRAL
CANADA...WITH A WEAK FRONTAL BOUNDARY SLIDING TO THE EAST...BUT
HAVING LITTLE IMPACT. NOT EXPECTING A LOT OF CHANGE IN THE OVERALL
PATTERN MON/TUESDAY...THE FORECAST REMAINS DRY WITH ANY NOTABLE
DISTURBANCES REMAINING TO THE NORTH...AND ABOVE AVERAGE TEMPS ALSO
REMAIN. WINDS THROUGH BOTH DAYS WILL HAVE THE DOWNSLOPING W/NWRLY
WINDS...AIDING IN THE MILD TEMPS. FORECAST HIGHS ON MONDAY ARE IN
THE MID 40S/MID 50S...BUT MONDAY NIGHT/TUESDAY...MODELS ARE SHOWING
A STRONGER DISTURBANCE SLIDING SOUTHEAST INTO THE GREAT LAKES
REGION...WHICH MAY USHER IN SOME SLIGHTLY COOLER AIR AIR...BUT HIGHS
ON TUESDAY ARE JUST A COUPLE DEGREES COOLER.
AS WE GET INTO TUESDAY NIGHT AND WEDNESDAY...LITTLE HAS CHANGED WITH
THE STORY SHOWING THE UPPER LEVEL PATTERN BECOMING MORE ZONAL IN
NATURE...AS A DISTURBANCE BEGINS TO MOVE ONTO THE PAC NW/WEST
COAST. STARTING TO SEE SOME DIFFERENCES BETWEEN MODELS ARISE...WITH
THE SFC PATTERN/WINDS AND THE MAGNITUDE OF WARM AIR ALOFT. CURRENT
HAVE HIGHS ON WED NOT SIGNIFICANTLY DIFFERENT THAN MON/TUES...BUT
CONFIDENCE IS NOT HIGH...AS THE POTENTIAL FOR INCREASING UPPER LEVEL
CLOUDS WILL BE A CONCERN.
CERTAINLY THE MORE INTERESTING TIME FRAME OF THE LONG TERM LIES
THURSDAY THROUGH SATURDAY...WITH IT STILL LOOKING TO BRING AN END TO
THE ABOVE AVERAGE TEMPS. BY 12Z THURSDAY...EXPECTING TO SEE A
TROUGH AXIS EXTENDING FROM NRN CANADA SW TOWARD THE WEST
COAST...WITH MORE SOUTHWESTERLY FLOW IN PLACE ACROSS THE PLAINS. BY
THE END OF THE DAY...MODELS SHOW THIS TROUGH DIGGING SOUTH TOWARD
THE SRN HALF OF CA...BECOMING CLOSED OFF...WITH THE WEAKER NRN
ENERGY EXPECTED TO GRADUALLY CONTINUE WORKING EAST. THE TIMING OF
THE ACCOMPANYING COLD FRONT...AND WHETHER THERE WILL BE ANY
PRECIP...ARE THE MAIN CONCERNS FOR THURSDAY. WILL CONTINUE TO KEEP
THE FORECAST DRY...BUT PRECIP MAY NOT BE FAR OUTSIDE THE NRN AND ERN
PORTIONS OF THE CWA. COOLED HIGHS A BIT FOR THURSDAY INTO THE LOWER
30S NORTH TO LOWER/MID 40S SOUTH...STILL SOME TIMING DIFFERENCES OF
THE COLDER AIR WORKING IN...BUT LATEST MODELS HAVE TRENDED QUICKER.
THURSDAY NIGHT AND FRIDAY...CONFIDENCE IN POPS IS NOT HIGH...AND
THEY REMAIN LOW. THE MAIN UPPER LEVEL LOW CONTINUES ITS SWING
SOUTH...BY 12Z LOOKS TO BE OVER THE NRN BAJA OF MEX...WHILE THE NRN
ENERGY HAS SHIFTED FURTHER EAST...AND THE LATEST EC/GFS/GEM ARE ALL
SHOWING THE CWA GETTING NO MORE THAN A GLANCING BLOW OF SOME LIGHT
SNOW...SET UP IN BETWEEN THE TWO MAIN DISTURBANCES. AT THIS POINT
FRIDAY CONTINUES TO LOOK LIKE THE COLDEST DAY OF THE FORECAST
PERIOD...AS THE COLDER AIR MASS/CENTER OF HIGH PRESSURE SETTLES IN
OVER THE REGION BEHIND THE FRONT...AND FORECAST HIGHS REMAIN IN THE
TEENS TO MID 20S.
FRIDAY NIGHT AND SATURDAY...THE MAIN CHANGE WAS TO REMOVE POPS
FRIDAY NIGHT...SOMETHING THAT MAY NEED TO BE CONSIDERED FOR SATURDAY
AS WELL...BUT AT THIS POINT KEPT SOME LOW POPS IN. THE SPREAD
BETWEEN MODELS WITH THE EVOLUTION OF THAT UPPER LEVEL LOW TO THE SW
IS SIZABLE...WITH THE GFS KEEPING IT CLOSED OFF AND WELL TO THE
SOUTH...SUGGESTING SAT WOULD BE DRY. THE ECMWF FILLS THE
LOW...BECOMING AN OPEN WAVE AND SLIDING PRIMARILY ACROSS THE SRN
PLAINS...BUT PERHAPS CLIPPING THE SERN CORNER OF THE CWA WITH SOME
PRECIP. TEMPS FOR SAT DO LOOK TO REBOUND A BIT AS THE COLDER AIR
MASS STARTS TO SLIDE EAST...BUT STILL LOOKING AT JUST MID/UPPER 20S.
PLENTY OF THINGS MAY SHIFT BETWEEN NOW AND THEN.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1123 AM CST SUN DEC 15 2013
CONFIDENCE IS QUITE HIGH IN VFR CEILING/VISIBILITY THROUGH THE
PERIOD...AS DESPITE PLENTY OF CLOUD COVER AT TIMES...ANY CEILING
IS EXPECTED TO REMAIN NEAR/ABOVE 10KT FT. SURFACE WIND
SPEED/DIRECTION WILL REMAIN FAIRLY CONSISTENT THROUGH THE PERIOD
AS WELL...GENERALLY FROM THE WEST TO WEST-NORTHWEST...SUSTAINED AT
SPEEDS NEAR/BELOW 12KT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...HEINLEIN
LONG TERM...ADO
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
533 AM CST SUN DEC 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 433 AM CST SUN DEC 15 2013
THE BIGGEST CHALLENGE WILL BE DETERMINING HIGH TEMPERATURES TODAY.
AT UPPER LEVELS...A RIDGE WILL BE IN THE PACIFIC WHILE A TROUGH IN
THE EASTERN UNITED STATES WILL EXIST. WE WILL BE IN NORTHWEST FLOW
IN BETWEEN WITH WARM AIR ADVECTION BEING ADVERTISED AT 850 MB AS THE
RIDGE NUDGES EAST. A SMALL PERTURBATION UPSTREAM WILL PASS ACROSS
THE CWA THIS MORNING...AND FOR TONIGHT...AN UPPER JET WILL APPROACH
AS THE LEFT FRONT QUADRANT WILL PROBABLY BE NEAR OUR AREA BY THE END
OF THE OVERNIGHT.
AT THE SURFACE...A WARM FRONT HAS NEARLY PASSED THROUGH THE ENTIRE
CWA...EXCEPT FOR THE FAR NORTHEASTERN CORNER. THIS FRONT SHOULD
CONTINUE TO EDGE FARTHER EAST THIS MORNING AND WE SHOULD BE
COMPLETELY IN THE WARM SECTOR FOR TODAY AND TONIGHT...ALTHOUGH THE
COLDER AIR WILL NOT BE TOO FAR TO THE EAST. GOING ABOVE GUIDANCE AS
RECENT BIAS CORRECTED MODEL VERIFICATION SUGGESTS THIS WOULD BE A
GOOD IDEA...AS WELL AS THE FACT THAT OUR SNOW PACK OVER THE CENTRAL
PART OF THE CWA IS FAST DWINDLING. A FLY IN THE OINTMENT COULD BE THE
MID TO UPPER LEVEL CLOUDINESS ASSOCIATED WITH THE PERTURBATION
MOVING ACROSS THE AREA DURING THE LATE MORNING INTO POSSIBLY THE
EARLY AFTERNOON...BUT THE HRRR SUGGESTS THAT WE SHOULD BE WELL CLEAR
OF MOST OF THIS SKY COVER BEFORE THE PEAK HEATING OF THE DAY OCCURS.
ANY PRECIPITATION SHOULD REMAIN WELL OFF THE NORTHEAST AND EAST OF
THE CWA WITH A PASSING WAVE AND NO MODEL IS ADVERTISING MEASURABLE
PRECIPITATION...ALTHOUGH THE WRF IS INDICATING PERHAPS SOME VERY
LIGHT NON-MEASURABLE PRECIPITATION IN OUR FAR NORTHEAST...BUT THIS
IS CLEARLY AN OUTLIER AND NOT CONSIDERED IN THIS FORECAST. THERE
COULD BE A BIT OF PATCHY FOG IN OUR EAST TONIGHT AS THE SREF IS
PICKING UP ON THIS. WITH WIND IN THE EAST NEAR CALM FOR PART OF THE
NIGHT AND DEWPOINT DEPRESSIONS PREDICTED TO BE LOW...WITH A LITTLE
BIT OF FRESHLY MELTED SNOW. THIS SHOULD NOT AMOUNT TO MUCH...AND BY
LATE OVERNIGHT...WIND WILL PROBABLY PICK UP A BIT TO DECREASE FOG
POTENTIAL. WITH THE APPROACHING LEFT FRONT QUADRANT OF AN UPPER
LEVEL JET...WE COULD ALSO HAVE SOME INCREASED CIRRUS BY LATE
OVERNIGHT AS WELL. GOING CLOSE TO GUIDANCE NUMBERS FOR LOWS TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 433 AM CST SUN DEC 15 2013
PRIMARY FORECAST CONCERNS THROUGH THE LONG TERM PERIOD LIE WITH A
CHANGE IN TEMPERATURES LATE IN THE WEEK...AND PRECIPITATION CHANCES.
THERE REALLY HASNT BEEN ANY SIGNIFICANT CHANGES IN THE MODELS
THROUGH THE PERIOD...SHOWING IT STARTING OUT MONDAY MORNING WITH
NORTHWESTERLY FLOW CONTINUING IN THE UPPER LEVELS...SET UP BETWEEN
AN AREA OF LOW PRESSURE OVER THE NERN CONUS...AND A RIDGE AXIS
EXTENDING ALONG WRN PORTIONS OF MEXICO UP INTO THE WEST COAST OF THE
CONUS. AT THE SURFACE...EXPECTING THE CWA TO BE BETWEEN HIGH
PRESSURE OVER THE SRN PLAINS AND LOW PRESSURE OVER CENTRAL
CANADA...WITH A WEAK FRONTAL BOUNDARY SLIDING TO THE EAST...BUT
HAVING LITTLE IMPACT. NOT EXPECTING A LOT OF CHANGE IN THE OVERALL
PATTERN MON/TUESDAY...THE FORECAST REMAINS DRY WITH ANY NOTABLE
DISTURBANCES REMAINING TO THE NORTH...AND ABOVE AVERAGE TEMPS ALSO
REMAIN. WINDS THROUGH BOTH DAYS WILL HAVE THE DOWNSLOPING W/NWRLY
WINDS...AIDING IN THE MILD TEMPS. FORECAST HIGHS ON MONDAY ARE IN
THE MID 40S/MID 50S...BUT MONDAY NIGHT/TUESDAY...MODELS ARE SHOWING
A STRONGER DISTURBANCE SLIDING SOUTHEAST INTO THE GREAT LAKES
REGION...WHICH MAY USHER IN SOME SLIGHTLY COOLER AIR AIR...BUT HIGHS
ON TUESDAY ARE JUST A COUPLE DEGREES COOLER.
AS WE GET INTO TUESDAY NIGHT AND WEDNESDAY...LITTLE HAS CHANGED WITH
THE STORY SHOWING THE UPPER LEVEL PATTERN BECOMING MORE ZONAL IN
NATURE...AS A DISTURBANCE BEGINS TO MOVE ONTO THE PAC NW/WEST
COAST. STARTING TO SEE SOME DIFFERENCES BETWEEN MODELS ARISE...WITH
THE SFC PATTERN/WINDS AND THE MAGNITUDE OF WARM AIR ALOFT. CURRENT
HAVE HIGHS ON WED NOT SIGNIFICANTLY DIFFERENT THAN MON/TUES...BUT
CONFIDENCE IS NOT HIGH...AS THE POTENTIAL FOR INCREASING UPPER LEVEL
CLOUDS WILL BE A CONCERN.
CERTAINLY THE MORE INTERESTING TIME FRAME OF THE LONG TERM LIES
THURSDAY THROUGH SATURDAY...WITH IT STILL LOOKING TO BRING AN END TO
THE ABOVE AVERAGE TEMPS. BY 12Z THURSDAY...EXPECTING TO SEE A
TROUGH AXIS EXTENDING FROM NRN CANADA SW TOWARD THE WEST
COAST...WITH MORE SOUTHWESTERLY FLOW IN PLACE ACROSS THE PLAINS. BY
THE END OF THE DAY...MODELS SHOW THIS TROUGH DIGGING SOUTH TOWARD
THE SRN HALF OF CA...BECOMING CLOSED OFF...WITH THE WEAKER NRN
ENERGY EXPECTED TO GRADUALLY CONTINUE WORKING EAST. THE TIMING OF
THE ACCOMPANYING COLD FRONT...AND WHETHER THERE WILL BE ANY
PRECIP...ARE THE MAIN CONCERNS FOR THURSDAY. WILL CONTINUE TO KEEP
THE FORECAST DRY...BUT PRECIP MAY NOT BE FAR OUTSIDE THE NRN AND ERN
PORTIONS OF THE CWA. COOLED HIGHS A BIT FOR THURSDAY INTO THE LOWER
30S NORTH TO LOWER/MID 40S SOUTH...STILL SOME TIMING DIFFERENCES OF
THE COLDER AIR WORKING IN...BUT LATEST MODELS HAVE TRENDED QUICKER.
THURSDAY NIGHT AND FRIDAY...CONFIDENCE IN POPS IS NOT HIGH...AND
THEY REMAIN LOW. THE MAIN UPPER LEVEL LOW CONTINUES ITS SWING
SOUTH...BY 12Z LOOKS TO BE OVER THE NRN BAJA OF MEX...WHILE THE NRN
ENERGY HAS SHIFTED FURTHER EAST...AND THE LATEST EC/GFS/GEM ARE ALL
SHOWING THE CWA GETTING NO MORE THAN A GLANCING BLOW OF SOME LIGHT
SNOW...SET UP IN BETWEEN THE TWO MAIN DISTURBANCES. AT THIS POINT
FRIDAY CONTINUES TO LOOK LIKE THE COLDEST DAY OF THE FORECAST
PERIOD...AS THE COLDER AIR MASS/CENTER OF HIGH PRESSURE SETTLES IN
OVER THE REGION BEHIND THE FRONT...AND FORECAST HIGHS REMAIN IN THE
TEENS TO MID 20S.
FRIDAY NIGHT AND SATURDAY...THE MAIN CHANGE WAS TO REMOVE POPS
FRIDAY NIGHT...SOMETHING THAT MAY NEED TO BE CONSIDERED FOR SATURDAY
AS WELL...BUT AT THIS POINT KEPT SOME LOW POPS IN. THE SPREAD
BETWEEN MODELS WITH THE EVOLUTION OF THAT UPPER LEVEL LOW TO THE SW
IS SIZABLE...WITH THE GFS KEEPING IT CLOSED OFF AND WELL TO THE
SOUTH...SUGGESTING SAT WOULD BE DRY. THE ECMWF FILLS THE
LOW...BECOMING AN OPEN WAVE AND SLIDING PRIMARILY ACROSS THE SRN
PLAINS...BUT PERHAPS CLIPPING THE SERN CORNER OF THE CWA WITH SOME
PRECIP. TEMPS FOR SAT DO LOOK TO REBOUND A BIT AS THE COLDER AIR
MASS STARTS TO SLIDE EAST...BUT STILL LOOKING AT JUST MID/UPPER 20S.
PLENTY OF THINGS MAY SHIFT BETWEEN NOW AND THEN.
&&
.AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z MONDAY MORNING)
ISSUED AT 530 AM CST SUN DEC 15 2013
VFR CONDITIONS ARE FORECAST. MID TO HIGH LEVEL SKY COVER SHOULD
DECREASE BY AFTERNOON ONCE AN UPPER LEVEL PERTURBATION PASSES TO
THE SOUTHEAST OF THE TERMINAL. WIND SHOULD REMAIN RELATIVELY
LIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...ADO
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
525 AM CST SUN DEC 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST SUN DEC 15 2013
TODAY AND TONIGHT...A POWERFUL THERMAL RIDGE WILL CONTINUE OPERATING
ACROSS THE FORECAST AREA. WINDS AT H850 MB CONTINUE AT 35 TO 45 KT
TODAY AND THEN WEAKEN TO AROUND 30 KTS TONIGHT. THE MID LEVEL CLOUD
DECK CURRENTLY ACROSS THE FCST AREA IS FCST TO SHIFT EAST AND EXIT
THE AREA THIS AFTN. AT THE SAME TIME A BANK OF CIRRUS ACROSS THE NRN
PLAINS WILL DRIFT ACROSS THE FCST AREA. THE TEMPERATURE FCST TODAY
USES THE WARM SIDE OF THE MODEL CONSENSUS PLUS ABOUT 3 DEGREES FOR
HIGHS IN THE UPPER 50S SOUTHWEST TO UPPER 30S NORTHEAST. THIS IS A
FEW DEGREES COOLER THAN THE HRRR MODEL BUT THAT MODEL WAS TOO WARM
SATURDAY.
THE QUESTION TONIGHT IS HOW COOL LOWS WILL GO. PRESUMABLY CIRRUS
WILL CONTINUE ACROSS THE FCST AREA BUT NONE OF THE MODELS SHOW MUCH
MID LEVEL CLOUDINESS WHICH WOULD KEEP MIN TEMPS IN THE 30S. THE FCST
IS FOR LOWER 20S ASSUMING CIRRUS CLOUDS.
OTHERWISE...500M AGL WINDS INCREASE TO 25 TO 30 KTS WHICH SUPPORTS
WINDS IN THE 20 TO 30 MPH RANGE AT THE SFC. THE FCST USES MULTIMODEL
DATA TODAY AND TONIGHT FOR WINDS BUT INCREASES WIND SPEEDS TO NEAR
THE MAV GUIDANCE...THE STRONGEST WIND DATA SET AVAILABLE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 355 AM CST SUN DEC 15 2013
PRIMARY FORECAST PROBLEMS THROUGH THIS PERIOD ARE TEMPERATURES AS
WELL AS PRECIPITATION CHANCES THURSDAY AND THURSDAY NIGHT.
AMPLIFIED UPPER LEVEL FLOW WITH RIDGING OVER THE EASTERN PACIFIC AND
WESTERN CONUS WITH TROUGHING OVER THE EASTERN HALF OF THE CONUS WILL
GIVE WAY TO A CHANGE BY MID WEEK AS THE UPPER LEVEL LOW CURRENTLY
OVER ONTARIO MOVES EAST DECREASING THE STRENGTH OF THE
TROUGH...WHILE A SERIES OF SHORTWAVE TROUGHS MOVE THROUGH THE
NORTHERN STREAM OUT OF RUSSIA AND ALASKA TO FLATTEN THE FLOW BY
MONDAY AND TUESDAY. SEVERAL WEAK SURFACE FRONTS WILL MOVE THROUGH
THE REGION WITH THE FIRST COMING THROUGH MONDAY MORNING AND ANOTHER
MONDAY NIGHT. EVEN WITH THESE FRONTS MOVING THROUGH...THE AIRMASS
WILL HAVE A PACIFIC INFLUENCE SO NOT EXPECTING TEMPERATURES TO BE
IMPACTED MUCH BY IT. WILL ALSO SEE WESTERLY FLOW IN THE LOW LEVELS
TO HELP WITH MIXING AND RAISING THE TEMPERATURES ON MONDAY. HIGH
PRESSURE WILL BUILD SOUTHEAST ACROSS THE AREA AND BY TUESDAY WILL
MOVE FURTHER SOUTHEAST BRINGING RETURN FLOW BACK INTO THE AREA.
AGAIN EXPECTING TEMPERATURES SIMILAR TO SUNDAY AND MONDAY.
TUESDAY NIGHT INTO WEDNESDAY THE CHANGING UPPER LEVEL PATTERN WILL
START TO BECOME APPARENT AS WHAT WILL BECOME A STRONG UPPER LEVEL
WAVE MOVES DOWN THE BRITISH COLUMBIA COAST AND INTO THE PACIFIC
NORTHWEST. MEANWHILE...THE UPPER LOW CURRENTLY WELL OFF THE
CALIFORNIA COAST WILL MOVE ONSHORE INTO SOUTHERN CALIFORNIA. AS
THESE TWO SYSTEMS BEGIN TO DEEPEN A TROUGH OVER THE WEST
COAST...UPPER LEVEL RIDGING WILL BUILD OVER THE PLAINS.
CONCURRENTLY...LOW PRESSURE AT THE SURFACE WILL DEVELOP OVER EASTERN
WYOMING WHICH WILL STRENGTHEN THE SOUTHERLY FLOW INTO THE LOCAL
AREA. WEDNESDAY SHOULD BE THE WARMEST DAY OF THE WEEK...HOWEVER
THERE ARE SOME DIFFERENCES IN HOW WARM IT WILL GET. THE ECMWF RISES
850MB TEMPERATURES TO NEAR 13C OVER THE SOUTHERN PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON...WHILE THE GFS DOESN/T WARM
THINGS UP AS MUCH. THIS WOULD MEAN A DIFFERENCE IN HIGHS BY 5 TO 10
DEGREES ACROSS THE FORECAST AREA. AT THIS TIME...TRENDED CLOSER TO
THE WARMER SOLUTION...YET NOT AS WARM AS SOME MODEL SOLUTIONS
SUGGESTING.
THE OTHER CONSIDERATION WHEN DEALING WITH THE TEMPERATURES IS THE
IMPACT OF THE SNOWPACK OVER THE NORTHERN PARTS OF THE FORECAST AREA.
SHOULD GET QUITE A BIT OF SNOW TO MELT OVER THE NEXT SEVERAL
DAYS...AND DO HAVE TEMPERATURES ON THE UPWARD TREND THROUGH
WEDNESDAY. BELIEVE WILL STILL SEE SOME INFLUENCE FROM THE SNOW
THROUGH THE WEEK...BUT HOW MUCH REMAINS IN QUESTION. WILL SEE HOW
TEMPERATURES WARM TODAY AND WILL SEE WHAT ADJUSTMENTS WILL NEED TO
BE MADE FOR THE FOLLOWING DAYS OVER THE NEXT SEVERAL FORECAST
CYCLES.
ON WEDNESDAY NIGHT THE UPPER LOW THAT MOVES INTO CALIFORNIA ON
WEDNESDAY WILL EJECT OUT OF THE UPPER TROUGH AND INTO THE CENTRAL
PLAINS. AS THIS OCCURS...THE WYOMING SURFACE LOW WILL MOVE INTO
EASTERN COLORADO...WITH THE ENTIRE SYSTEM WEAKENING. GOING INTO
THURSDAY THE SURFACE LOW WILL MOVE ACROSS KANSAS WITH AN INVERTED
TROUGH PASSING ACROSS THE LOCAL FORECAST AREA. THE MAJORITY OF
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL REMAIN ACROSS KANSAS AND
SOUTHEAST NEBRASKA SO NOT EXPECTING ANY PRECIPITATION INVOLVED WITH
IT.
FOCUS THEN TURNS TO THE NEXT ARCTIC AIRMASS TO PUSH THROUGH THE
PLAINS. THE ARCTIC FRONT IS NOW BEING TIMED TO MOVE SOUTH ACROSS
NEBRASKA DURING THE DAY THURSDAY WITH PRECIPITATION MOVING IN BEHIND
THE FRONT. THE MUCH COLDER AIR WILL LAG BEHIND THE FRONT...HOWEVER
WITH COLD AIR ADVECTION ONGOING THROUGH THE DAY AM QUESTIONING HOW
WARM IT WILL GET...OR WHAT TIME HIGHS WILL BE REACHED. LOCATIONS
ACROSS THE NORTH MAY SEE HIGHS IN THE MORNING...WHILE THE SOUTHERN
PARTS OF THE AREA MAY HAVE SOME TIME TO WARM UP BEFORE THE BIG PUSH
OF COLD AIR. DID LOWER HIGHS SLIGHTLY FOR THURSDAY...BUT WILL LIKELY
NEED FURTHER ADJUSTMENTS UNTIL A BETTER HANDLE IS ON THE MODELS FOR
THIS SYSTEM. THE PRESSURE GRADIENT WILL TIGHTEN BEHIND THE
FRONT...WITH STRONG NORTHERLY WINDS EXPECTED ON THURSDAY INTO
THURSDAY NIGHT. BY FRIDAY HIGH PRESSURE WILL BUILD IN WITH THE
PRESSURE GRADIENT RELAXING SO WINDS SHOULDN/T BE AS STRONG. COLDER
AND BELOW NORMAL TEMPERATURES WILL THEN CONTINUE INTO THE WEEKEND AS
THE TROUGH AXIS MOVES ACROSS THE CONUS THROUGH THE WEEKEND. CURRENT
MODELS AREN/T QUITE AS COLD WITH THE TEMPERATURES FOR FRIDAY AND
SATURDAY AS PREVIOUS RUNS...BUT STILL BRING 850MB TEMPERATURES OF
-15C TO -17C INTO THE CENTRAL PLAINS.
IN TERMS OF PRECIPITATION...THERE SEEMS TO BE AN ISSUE WITH A POCKET
OF DRY AIR IN THE MID LEVELS BEHIND THE FRONT WHICH MAY CAUSE
PROBLEMS WITH THE DEVELOPMENT OF PRECIPITATION. THERE CONTINUES TO
BE A SLIGHT SIGNAL FOR SOME DRIZZLE ON THURSDAY PRIOR TO THE COLUMN
BECOMING SATURATED THURSDAY NIGHT. HOWEVER...EVEN IN THE LOW
LEVELS...THE AIR WASN/T COMPLETELY SATURATED EITHER SO WILL STILL
NOT MENTION ANY DRIZZLE YET IN THE FORECAST. BESIDES THIS OUTSIDE
CHANCE FOR DRIZZLE...THE POST-FRONTAL PRECIPITATION SHOULD BE QUITE
LIGHT. PRECIPITABLE WATER AMOUNTS AREN/T BAD...HOWEVER THE SIGNALS
FOR ANY FRONTOGENESIS ARE NOT STRONG AND THE MOISTURE DOES NOT STAY
LONG BEFORE MUCH DRIER AIR PUSHES IN TO DRY OUT THE COLUMN SO NOT
EXPECTING ANY HEAVY PRECIPITATION AMOUNTS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 522 AM CST SUN DEC 15 2013
VFR IS EXPECTED ALL AREAS TODAY AND TONIGHT.
NORTHWEST FLOW WILL CONTINUE AT ALL LEVELS. THE BANK OF MID LEVEL
CLOUDS WILL MOVE EAST TODAY AND BE REPLACED BY BROKEN HIGH CLOUDS
LATE THIS AFTERNOON AND TONIGHT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
440 AM CST SUN DEC 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 433 AM CST SUN DEC 15 2013
THE BIGGEST CHALLENGE WILL BE DETERMINING HIGH TEMPERATURES TODAY.
AT UPPER LEVELS...A RIDGE WILL BE IN THE PACIFIC WHILE A TROUGH IN
THE EASTERN UNITED STATES WILL EXIST. WE WILL BE IN NORTHWEST FLOW
IN BETWEEN WITH WARM AIR ADVECTION BEING ADVERTISED AT 850 MB AS THE
RIDGE NUDGES EAST. A SMALL PERTURBATION UPSTREAM WILL PASS ACROSS
THE CWA THIS MORNING...AND FOR TONIGHT...AN UPPER JET WILL APPROACH
AS THE LEFT FRONT QUADRANT WILL PROBABLY BE NEAR OUR AREA BY THE END
OF THE OVERNIGHT.
AT THE SURFACE...A WARM FRONT HAS NEARLY PASSED THROUGH THE ENTIRE
CWA...EXCEPT FOR THE FAR NORTHEASTERN CORNER. THIS FRONT SHOULD
CONTINUE TO EDGE FARTHER EAST THIS MORNING AND WE SHOULD BE
COMPLETELY IN THE WARM SECTOR FOR TODAY AND TONIGHT...ALTHOUGH THE
COLDER AIR WILL NOT BE TOO FAR TO THE EAST. GOING ABOVE GUIDANCE AS
RECENT BIAS CORRECTED MODEL VERIFICATION SUGGESTS THIS WOULD BE A
GOOD IDEA...AS WELL AS THE FACT THAT OUR SNOW PACK OVER THE CENTRAL
PART OF THE CWA IS FAST DWINDLING. A FLY IN THE OINTMENT COULD BE THE
MID TO UPPER LEVEL CLOUDINESS ASSOCIATED WITH THE PERTURBATION
MOVING ACROSS THE AREA DURING THE LATE MORNING INTO POSSIBLY THE
EARLY AFTERNOON...BUT THE HRRR SUGGESTS THAT WE SHOULD BE WELL CLEAR
OF MOST OF THIS SKY COVER BEFORE THE PEAK HEATING OF THE DAY OCCURS.
ANY PRECIPITATION SHOULD REMAIN WELL OFF THE NORTHEAST AND EAST OF
THE CWA WITH A PASSING WAVE AND NO MODEL IS ADVERTISING MEASURABLE
PRECIPITATION...ALTHOUGH THE WRF IS INDICATING PERHAPS SOME VERY
LIGHT NON-MEASURABLE PRECIPITATION IN OUR FAR NORTHEAST...BUT THIS
IS CLEARLY AN OUTLIER AND NOT CONSIDERED IN THIS FORECAST. THERE
COULD BE A BIT OF PATCHY FOG IN OUR EAST TONIGHT AS THE SREF IS
PICKING UP ON THIS. WITH WIND IN THE EAST NEAR CALM FOR PART OF THE
NIGHT AND DEWPOINT DEPRESSIONS PREDICTED TO BE LOW...WITH A LITTLE
BIT OF FRESHLY MELTED SNOW. THIS SHOULD NOT AMOUNT TO MUCH...AND BY
LATE OVERNIGHT...WIND WILL PROBABLY PICK UP A BIT TO DECREASE FOG
POTENTIAL. WITH THE APPROACHING LEFT FRONT QUADRANT OF AN UPPER
LEVEL JET...WE COULD ALSO HAVE SOME INCREASED CIRRUS BY LATE
OVERNIGHT AS WELL. GOING CLOSE TO GUIDANCE NUMBERS FOR LOWS TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 433 AM CST SUN DEC 15 2013
PRIMARY FORECAST CONCERNS THROUGH THE LONG TERM PERIOD LIE WITH A
CHANGE IN TEMPERATURES LATE IN THE WEEK...AND PRECIPITATION CHANCES.
THERE REALLY HASNT BEEN ANY SIGNIFICANT CHANGES IN THE MODELS
THROUGH THE PERIOD...SHOWING IT STARTING OUT MONDAY MORNING WITH
NORTHWESTERLY FLOW CONTINUING IN THE UPPER LEVELS...SET UP BETWEEN
AN AREA OF LOW PRESSURE OVER THE NERN CONUS...AND A RIDGE AXIS
EXTENDING ALONG WRN PORTIONS OF MEXICO UP INTO THE WEST COAST OF THE
CONUS. AT THE SURFACE...EXPECTING THE CWA TO BE BETWEEN HIGH
PRESSURE OVER THE SRN PLAINS AND LOW PRESSURE OVER CENTRAL
CANADA...WITH A WEAK FRONTAL BOUNDARY SLIDING TO THE EAST...BUT
HAVING LITTLE IMPACT. NOT EXPECTING A LOT OF CHANGE IN THE OVERALL
PATTERN MON/TUESDAY...THE FORECAST REMAINS DRY WITH ANY NOTABLE
DISTURBANCES REMAINING TO THE NORTH...AND ABOVE AVERAGE TEMPS ALSO
REMAIN. WINDS THROUGH BOTH DAYS WILL HAVE THE DOWNSLOPING W/NWRLY
WINDS...AIDING IN THE MILD TEMPS. FORECAST HIGHS ON MONDAY ARE IN
THE MID 40S/MID 50S...BUT MONDAY NIGHT/TUESDAY...MODELS ARE SHOWING
A STRONGER DISTURBANCE SLIDING SOUTHEAST INTO THE GREAT LAKES
REGION...WHICH MAY USHER IN SOME SLIGHTLY COOLER AIR AIR...BUT HIGHS
ON TUESDAY ARE JUST A COUPLE DEGREES COOLER.
AS WE GET INTO TUESDAY NIGHT AND WEDNESDAY...LITTLE HAS CHANGED WITH
THE STORY SHOWING THE UPPER LEVEL PATTERN BECOMING MORE ZONAL IN
NATURE...AS A DISTURBANCE BEGINS TO MOVE ONTO THE PAC NW/WEST
COAST. STARTING TO SEE SOME DIFFERENCES BETWEEN MODELS ARISE...WITH
THE SFC PATTERN/WINDS AND THE MAGNITUDE OF WARM AIR ALOFT. CURRENT
HAVE HIGHS ON WED NOT SIGNIFICANTLY DIFFERENT THAN MON/TUES...BUT
CONFIDENCE IS NOT HIGH...AS THE POTENTIAL FOR INCREASING UPPER LEVEL
CLOUDS WILL BE A CONCERN.
CERTAINLY THE MORE INTERESTING TIME FRAME OF THE LONG TERM LIES
THURSDAY THROUGH SATURDAY...WITH IT STILL LOOKING TO BRING AN END TO
THE ABOVE AVERAGE TEMPS. BY 12Z THURSDAY...EXPECTING TO SEE A
TROUGH AXIS EXTENDING FROM NRN CANADA SW TOWARD THE WEST
COAST...WITH MORE SOUTHWESTERLY FLOW IN PLACE ACROSS THE PLAINS. BY
THE END OF THE DAY...MODELS SHOW THIS TROUGH DIGGING SOUTH TOWARD
THE SRN HALF OF CA...BECOMING CLOSED OFF...WITH THE WEAKER NRN
ENERGY EXPECTED TO GRADUALLY CONTINUE WORKING EAST. THE TIMING OF
THE ACCOMPANYING COLD FRONT...AND WHETHER THERE WILL BE ANY
PRECIP...ARE THE MAIN CONCERNS FOR THURSDAY. WILL CONTINUE TO KEEP
THE FORECAST DRY...BUT PRECIP MAY NOT BE FAR OUTSIDE THE NRN AND ERN
PORTIONS OF THE CWA. COOLED HIGHS A BIT FOR THURSDAY INTO THE LOWER
30S NORTH TO LOWER/MID 40S SOUTH...STILL SOME TIMING DIFFERENCES OF
THE COLDER AIR WORKING IN...BUT LATEST MODELS HAVE TRENDED QUICKER.
THURSDAY NIGHT AND FRIDAY...CONFIDENCE IN POPS IS NOT HIGH...AND
THEY REMAIN LOW. THE MAIN UPPER LEVEL LOW CONTINUES ITS SWING
SOUTH...BY 12Z LOOKS TO BE OVER THE NRN BAJA OF MEX...WHILE THE NRN
ENERGY HAS SHIFTED FURTHER EAST...AND THE LATEST EC/GFS/GEM ARE ALL
SHOWING THE CWA GETTING NO MORE THAN A GLANCING BLOW OF SOME LIGHT
SNOW...SET UP IN BETWEEN THE TWO MAIN DISTURBANCES. AT THIS POINT
FRIDAY CONTINUES TO LOOK LIKE THE COLDEST DAY OF THE FORECAST
PERIOD...AS THE COLDER AIR MASS/CENTER OF HIGH PRESSURE SETTLES IN
OVER THE REGION BEHIND THE FRONT...AND FORECAST HIGHS REMAIN IN THE
TEENS TO MID 20S.
FRIDAY NIGHT AND SATURDAY...THE MAIN CHANGE WAS TO REMOVE POPS
FRIDAY NIGHT...SOMETHING THAT MAY NEED TO BE CONSIDERED FOR SATURDAY
AS WELL...BUT AT THIS POINT KEPT SOME LOW POPS IN. THE SPREAD
BETWEEN MODELS WITH THE EVOLUTION OF THAT UPPER LEVEL LOW TO THE SW
IS SIZABLE...WITH THE GFS KEEPING IT CLOSED OFF AND WELL TO THE
SOUTH...SUGGESTING SAT WOULD BE DRY. THE ECMWF FILLS THE
LOW...BECOMING AN OPEN WAVE AND SLIDING PRIMARILY ACROSS THE SRN
PLAINS...BUT PERHAPS CLIPPING THE SERN CORNER OF THE CWA WITH SOME
PRECIP. TEMPS FOR SAT DO LOOK TO REBOUND A BIT AS THE COLDER AIR
MASS STARTS TO SLIDE EAST...BUT STILL LOOKING AT JUST MID/UPPER 20S.
PLENTY OF THINGS MAY SHIFT BETWEEN NOW AND THEN.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1152 PM CST SAT DEC 14 2013
MAINLY MID-LEVEL SKY COVER IS EXPECTED AS A WARM FRONT MOVES EAST.
WIND SHOULD BE LIGHT FROM THE WEST BEHIND THE FRONT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...ADO
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
356 AM CST SUN DEC 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST SUN DEC 15 2013
TODAY AND TONIGHT...A POWERFUL THERMAL RIDGE WILL CONTINUE OPERATING
ACROSS THE FORECAST AREA. WINDS AT H850 MB CONTINUE AT 35 TO 45 KT
TODAY AND THEN WEAKEN TO AROUND 30 KTS TONIGHT. THE MID LEVEL CLOUD
DECK CURRENTLY ACROSS THE FCST AREA IS FCST TO SHIFT EAST AND EXIT
THE AREA THIS AFTN. AT THE SAME TIME A BANK OF CIRRUS ACROSS THE NRN
PLAINS WILL DRIFT ACROSS THE FCST AREA. THE TEMPERATURE FCST TODAY
USES THE WARM SIDE OF THE MODEL CONSENSUS PLUS ABOUT 3 DEGREES FOR
HIGHS IN THE UPPER 50S SOUTHWEST TO UPPER 30S NORTHEAST. THIS IS A
FEW DEGREES COOLER THAN THE HRRR MODEL BUT THAT MODEL WAS TOO WARM
SATURDAY.
THE QUESTION TONIGHT IS HOW COOL LOWS WILL GO. PRESUMABLY CIRRUS
WILL CONTINUE ACROSS THE FCST AREA BUT NONE OF THE MODELS SHOW MUCH
MID LEVEL CLOUDINESS WHICH WOULD KEEP MIN TEMPS IN THE 30S. THE FCST
IS FOR LOWER 20S ASSUMING CIRRUS CLOUDS.
OTHERWISE...500M AGL WINDS INCREASE TO 25 TO 30 KTS WHICH SUPPORTS
WINDS IN THE 20 TO 30 MPH RANGE AT THE SFC. THE FCST USES MULTIMODEL
DATA TODAY AND TONIGHT FOR WINDS BUT INCREASES WIND SPEEDS TO NEAR
THE MAV GUIDANCE...THE STRONGEST WIND DATA SET AVAILABLE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 355 AM CST SUN DEC 15 2013
PRIMARY FORECAST PROBLEMS THROUGH THIS PERIOD ARE TEMPERATURES AS
WELL AS PRECIPITATION CHANCES THURSDAY AND THURSDAY NIGHT.
AMPLIFIED UPPER LEVEL FLOW WITH RIDGING OVER THE EASTERN PACIFIC AND
WESTERN CONUS WITH TROUGHING OVER THE EASTERN HALF OF THE CONUS WILL
GIVE WAY TO A CHANGE BY MID WEEK AS THE UPPER LEVEL LOW CURRENTLY
OVER ONTARIO MOVES EAST DECREASING THE STRENGTH OF THE
TROUGH...WHILE A SERIES OF SHORTWAVE TROUGHS MOVE THROUGH THE
NORTHERN STREAM OUT OF RUSSIA AND ALASKA TO FLATTEN THE FLOW BY
MONDAY AND TUESDAY. SEVERAL WEAK SURFACE FRONTS WILL MOVE THROUGH
THE REGION WITH THE FIRST COMING THROUGH MONDAY MORNING AND ANOTHER
MONDAY NIGHT. EVEN WITH THESE FRONTS MOVING THROUGH...THE AIRMASS
WILL HAVE A PACIFIC INFLUENCE SO NOT EXPECTING TEMPERATURES TO BE
IMPACTED MUCH BY IT. WILL ALSO SEE WESTERLY FLOW IN THE LOW LEVELS
TO HELP WITH MIXING AND RAISING THE TEMPERATURES ON MONDAY. HIGH
PRESSURE WILL BUILD SOUTHEAST ACROSS THE AREA AND BY TUESDAY WILL
MOVE FURTHER SOUTHEAST BRINGING RETURN FLOW BACK INTO THE AREA.
AGAIN EXPECTING TEMPERATURES SIMILAR TO SUNDAY AND MONDAY.
TUESDAY NIGHT INTO WEDNESDAY THE CHANGING UPPER LEVEL PATTERN WILL
START TO BECOME APPARENT AS WHAT WILL BECOME A STRONG UPPER LEVEL
WAVE MOVES DOWN THE BRITISH COLUMBIA COAST AND INTO THE PACIFIC
NORTHWEST. MEANWHILE...THE UPPER LOW CURRENTLY WELL OFF THE
CALIFORNIA COAST WILL MOVE ONSHORE INTO SOUTHERN CALIFORNIA. AS
THESE TWO SYSTEMS BEGIN TO DEEPEN A TROUGH OVER THE WEST
COAST...UPPER LEVEL RIDGING WILL BUILD OVER THE PLAINS.
CONCURRENTLY...LOW PRESSURE AT THE SURFACE WILL DEVELOP OVER EASTERN
WYOMING WHICH WILL STRENGTHEN THE SOUTHERLY FLOW INTO THE LOCAL
AREA. WEDNESDAY SHOULD BE THE WARMEST DAY OF THE WEEK...HOWEVER
THERE ARE SOME DIFFERENCES IN HOW WARM IT WILL GET. THE ECMWF RISES
850MB TEMPERATURES TO NEAR 13C OVER THE SOUTHERN PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON...WHILE THE GFS DOESN/T WARM
THINGS UP AS MUCH. THIS WOULD MEAN A DIFFERENCE IN HIGHS BY 5 TO 10
DEGREES ACROSS THE FORECAST AREA. AT THIS TIME...TRENDED CLOSER TO
THE WARMER SOLUTION...YET NOT AS WARM AS SOME MODEL SOLUTIONS
SUGGESTING.
THE OTHER CONSIDERATION WHEN DEALING WITH THE TEMPERATURES IS THE
IMPACT OF THE SNOWPACK OVER THE NORTHERN PARTS OF THE FORECAST AREA.
SHOULD GET QUITE A BIT OF SNOW TO MELT OVER THE NEXT SEVERAL
DAYS...AND DO HAVE TEMPERATURES ON THE UPWARD TREND THROUGH
WEDNESDAY. BELIEVE WILL STILL SEE SOME INFLUENCE FROM THE SNOW
THROUGH THE WEEK...BUT HOW MUCH REMAINS IN QUESTION. WILL SEE HOW
TEMPERATURES WARM TODAY AND WILL SEE WHAT ADJUSTMENTS WILL NEED TO
BE MADE FOR THE FOLLOWING DAYS OVER THE NEXT SEVERAL FORECAST
CYCLES.
ON WEDNESDAY NIGHT THE UPPER LOW THAT MOVES INTO CALIFORNIA ON
WEDNESDAY WILL EJECT OUT OF THE UPPER TROUGH AND INTO THE CENTRAL
PLAINS. AS THIS OCCURS...THE WYOMING SURFACE LOW WILL MOVE INTO
EASTERN COLORADO...WITH THE ENTIRE SYSTEM WEAKENING. GOING INTO
THURSDAY THE SURFACE LOW WILL MOVE ACROSS KANSAS WITH AN INVERTED
TROUGH PASSING ACROSS THE LOCAL FORECAST AREA. THE MAJORITY OF
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL REMAIN ACROSS KANSAS AND
SOUTHEAST NEBRASKA SO NOT EXPECTING ANY PRECIPITATION INVOLVED WITH
IT.
FOCUS THEN TURNS TO THE NEXT ARCTIC AIRMASS TO PUSH THROUGH THE
PLAINS. THE ARCTIC FRONT IS NOW BEING TIMED TO MOVE SOUTH ACROSS
NEBRASKA DURING THE DAY THURSDAY WITH PRECIPITATION MOVING IN BEHIND
THE FRONT. THE MUCH COLDER AIR WILL LAG BEHIND THE FRONT...HOWEVER
WITH COLD AIR ADVECTION ONGOING THROUGH THE DAY AM QUESTIONING HOW
WARM IT WILL GET...OR WHAT TIME HIGHS WILL BE REACHED. LOCATIONS
ACROSS THE NORTH MAY SEE HIGHS IN THE MORNING...WHILE THE SOUTHERN
PARTS OF THE AREA MAY HAVE SOME TIME TO WARM UP BEFORE THE BIG PUSH
OF COLD AIR. DID LOWER HIGHS SLIGHTLY FOR THURSDAY...BUT WILL LIKELY
NEED FURTHER ADJUSTMENTS UNTIL A BETTER HANDLE IS ON THE MODELS FOR
THIS SYSTEM. THE PRESSURE GRADIENT WILL TIGHTEN BEHIND THE
FRONT...WITH STRONG NORTHERLY WINDS EXPECTED ON THURSDAY INTO
THURSDAY NIGHT. BY FRIDAY HIGH PRESSURE WILL BUILD IN WITH THE
PRESSURE GRADIENT RELAXING SO WINDS SHOULDN/T BE AS STRONG. COLDER
AND BELOW NORMAL TEMPERATURES WILL THEN CONTINUE INTO THE WEEKEND AS
THE TROUGH AXIS MOVES ACROSS THE CONUS THROUGH THE WEEKEND. CURRENT
MODELS AREN/T QUITE AS COLD WITH THE TEMPERATURES FOR FRIDAY AND
SATURDAY AS PREVIOUS RUNS...BUT STILL BRING 850MB TEMPERATURES OF
-15C TO -17C INTO THE CENTRAL PLAINS.
IN TERMS OF PRECIPITATION...THERE SEEMS TO BE AN ISSUE WITH A POCKET
OF DRY AIR IN THE MID LEVELS BEHIND THE FRONT WHICH MAY CAUSE
PROBLEMS WITH THE DEVELOPMENT OF PRECIPITATION. THERE CONTINUES TO
BE A SLIGHT SIGNAL FOR SOME DRIZZLE ON THURSDAY PRIOR TO THE COLUMN
BECOMING SATURATED THURSDAY NIGHT. HOWEVER...EVEN IN THE LOW
LEVELS...THE AIR WASN/T COMPLETELY SATURATED EITHER SO WILL STILL
NOT MENTION ANY DRIZZLE YET IN THE FORECAST. BESIDES THIS OUTSIDE
CHANCE FOR DRIZZLE...THE POST-FRONTAL PRECIPITATION SHOULD BE QUITE
LIGHT. PRECIPITABLE WATER AMOUNTS AREN/T BAD...HOWEVER THE SIGNALS
FOR ANY FRONTOGENESIS ARE NOT STRONG AND THE MOISTURE DOES NOT STAY
LONG BEFORE MUCH DRIER AIR PUSHES IN TO DRY OUT THE COLUMN SO NOT
EXPECTING ANY HEAVY PRECIPITATION AMOUNTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1025 PM CST SAT DEC 14 2013
CEILINGS MOVING ACROSS CENTRAL AND WESTERN NEBRASKA TONIGHT ARE
FORECAST TO REMAIN 3500 FEET AGL OR HIGHER. THOSE CLOUDS ARE THEN
EXPECTED TO SCATTER OUT LATE MORNING IN SOUTHWEST NEBRASKA AND BY
LATE AFTERNOON IN NORTHERN NEBRASKA.
WIND IS FORECAST TO REMAIN BELOW 10KT TONIGHT AND ARE LIKELY TO
BECOME 280-310 AT 11-14G18-22KT BY ABOUT 18Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
644 PM EST MON DEC 16 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL TRACK FROM THE UPPER OHIO VALLEY TO
OFF THE NEW JERSEY COAST TUESDAY AFTERNOON. THIS LOW WILL BRING A
LIGHT SNOWFALL TO MUCH OF CENTRAL NEW YORK, AND A MODERATE
SNOWFALL TO PARTS OF NORTHEAST PENNSYLVANIA AND THE CATSKILLS OF
NEW YORK FROM LATE TONIGHT AND TUESDAY. TUESDAY NIGHT AND
WEDNESDAY, COLD AIR WILL REMAIN WITH MORE LAKE EFFECT SNOW
SHOWERS AND FLURRIES. MUCH MILDER AIR WILL BEGIN TO RETURN TO THE
REGION BY THE END OF THE WEEK AS A SOUTHWESTERLY FLOW OF AIR
BECOMES ESTABLISHED ACROSS THE EASTERN UNITED STATES.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SINGLE SHORELINE LAKE EFFECT SNOW BAND OFF LAKE ONTARIO HAS NOW
SHIFTED INLAND AND WAS BREAKING UP INTO MULTIPLE BANDS OF LESS
ORGANIZED SNOW SHOWERS AND FLURRIES. RAP MODEL SOUNDINGS SHOW A
PRONOUNCED SHIFT TO NW FLOW UNDER THE INVERSION AT 18-19Z AND
INDEED THE KTYX 88D SHOWS A NW FLO ARND 340 DEGREES AT 3000 FEET
AGL. IN ADDTN...SUBSDC WILL CONT TO PUSH THE INVERSION DOWN WHICH
AS PER MODEL SOUNDINGS IS PROJECTED TO DROP TO ARND 3000 FEET AGL
FROM 7000 FEET AGL AT PRESENT. BY 00 TO 01Z...THE LL FLOW BACKS TO
THE SW. THIS IN EFFECT WILL CUT OFF THE LES SNOWS AND FLURRIES
BY 03Z THE LATEST. FOR ACCUMULATIONS...I CAN SEE ANTHR 1-2 INCHES
BTWN SYR AND CORTLAND IN THE HIGHLANDS OF CENTRAL NY. REST OF CWA
WILL SEE PC SKIES THIS AFTERNOON WITH SCATTERED FLURRIES AS THE
TEMPERATURES IN THE BNDRY LAYER UNDER THE INVERSION WERE IN THE
MAXIMUM ZONE OF ICE CRYSTAL FORMATION ARND -12C TO 15C (AT 1000 MB
MAX GROWTH IS -12C). HENCE FLOW OVER THE HILLS AND EVEN A LITTLE
CONVECTIVE OVERTURNING IN SC CLDS WILL SPIT OUT SOME FLURRIES.
FARTHER AWAY FROM THE LAKES IN NE PA...WHERE BNDRY LAYER WAS
DRIER...FLURRIES WERE SUBLIMATING SO HAVE NO POPS THERE.
AFTER SUNSET...WITH THE LOSS OF THE SFC HEATING AND THE LL FLOW
TURNING MORE W-SW...SKIES SHUD CLR AND THE LES ACVTY WILL END AS
STATED ABV. I SEE RAPID COOLING IN THE BNDRY LAYER...UNTIL HIGHER
CLDS BEGIN ARRIVING FROM THE SW BTWN 6 AND 9Z AHEAD OF CLIPPER
SYSTEM. I HAVE SOME LIGHT SNOWS AND FLURRIES ARRIVING FROM 9Z TO
12Z ACRS ENTIRE FORECAST AREA FROM APPROACHING CLIPPER SYSTEM. SO
I HAVE ADDED POPS LATE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
ISSUED WINTER WEATHER ADVY FOR TUESDAY FROM 5 AM TO 5 PM FOR THE
APPROACHING CLIPPER-LIKE SYSTEM. ALL SYNOPTIC AND MESOSCALE MODELS
SHOW A DECENT SHOT OF SIGNIFICANT WAA/ISEN LIFT WITH ENUF MOISTURE
TO SQUEEZE OUT AT LEAST .1 TO .2 INCHES OF QPF...WITH POTENTIALLY
A LITTLE MORE ACRS PIKE/SULLIVAN CO/S. ASSUMING A 15 TO 1 SNOW
TO QPF RATIO I CAN SEE ARND 3-5 INCHES IN THESE TWO COUNTIES WHICH
MEETS OUR ADVY CRITERIA OF 4 INCHES/12 HOURS. SO IN COLLABORATION
WITH SURROUNDING OFFICES WE ISSUED A WW ADVY FOR SNOW. WPC WWD
GRAPHIC ALSO IN LINE SHOWING A SMALL AREA OF 4-6 INCHES IN
SULLIVAN/PIKE CO/S. REST OF CWA WE FEEL WILL SEE MAINLY 1-3
INCHES. WILL MENTION IN HWO AS ROADS LIKELY WILL BE HAZARDOUS TO
SOME EXTENT TUE AM FOR REST OF FORECAST AREA.
AFTER THIS SYSTEM PASSES BY...AN UPR LVL TROF WILL PUSH SOUTHEAST
ACRS THE REGION WITH MODEST CAA. I KEPT CHC SN SHOWERS/FLURRIES IN
AS SOME LAKE EFFECT MOISTURE WILL CONT TO STREAM INTO C NY AND NRN
PA UNDER THIS COLDER AIR ALOFT. HIGHEST POPS AND AMNTS WILL BE IN
OUR FAR NRN COUNTIES DIRECTLY DOWNWIND OF LAKE ONTARIO. MAY NEED
TO CONSIDER LES ADVYS LATER IN THIS PERIOD FOR MAINLY WEDNESDAY.
THEN FOR WED NGT SOME WAA KICKS IN COINCIDENT WITH RISING HGHTS SO
THERE LIKELY WILL BE SOME LIMITED AMNTS OF LIFTG TO SUPPORT JUST A
CHC POPS FOR SN SHOWERS/FLURRIES.
THEN FOR THURSDAY...SW FLO SETS UP IN EARNEST AS TEMPS BEGIN TO
SOAR AT 850 MB. THIS WILL CUT OFF ALL LAKE EFFECT MOISTURE AND
START A TURN TO MUCH MILDER WX FOR OUR REGION.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MEDIUM RANGE MODELS ARE NOW IN MUCH BETTER AGREEMENT DURING THIS
ACTIVE EXTENDED FORECAST PERIOD. THE UPPER LEVEL PATTERN WILL
FEATURE A DEEP WESTERN TROF AND STRONG SOUTHEAST RIDGE THAT WILL
PROVIDE A FAIRLY MILD DEEP SOUTHWEST FLOW ACROSS THE NORTHEAST.
AT THE SFC, THURSDAY NIGHT THROUGH FRIDAY NIGHT, SFC LOW PRES WILL
TRACK FROM THE MID WEST NORTHEAST ACROSS THE UPPER GREAT LAKES
THEN EAST ACROSS NEARBY SOUTHERN CANADA. AS THIS SYSTEM PASSES TO
OUR WEST WARM AIR WILL OVERSPREAD THE AREA BRINGING MAINLY RAIN
SHOWERS ON FRIDAY. FRIDAY NIGHT THE TRAILING COLD FRONT IS
EXPECTED TO CROSS THE AREA WITH MIXED RAIN/SNOW SHOWERS
POSSIBLE.
SATURDAY MAY BE MAINLY DRY AS SFC HIGH PRES BRIEFLY BUILDS SOUTH
OVER THE NORTHEAST. SATURDAY NIGHT THROUGH SUNDAY NIGHT, ANOTHER
LOW PRES SYSTEM WILL MOVE NORTHEAST ALONG THIS STALLED BOUNDARY
AND INTO THE NORTHEAST. A STRONG THERMAL GRADIENT WILL RESIDE OVER
THE REGION THEREFORE DETERMINING P-TYPE WILL BE VERY DIFFICULT.
FOR NOW WILL MENTION BOTH RAIN/SNOW. CURRENT TREND IS FOR A WARMER
SOLUTION SO THIS SECOND WAVE COULD BE ASSOCIATED WITH SIGNIFICANT
RAINFALL. STILL MUCH TO BE DETERMINED.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
630 PM UPDATE...
LAKE EFFECT WINDING DOWN. MOST OF IT JUST ALONG THE SE SHORE OF
LAKE ONTARIO. IT COULD EXTEND INTO KSYR WITH IFR VSBY/MVFR CIGS
UNTIL 2Z AND KRME WITH MVFR VSBY/CIG UNTIL 2Z. ELSEWHERE VFR MUCH
OF THE NIGHT.
A FAST MOVING CLIPPER WILL BRING SNOW STARTING AROUND 10Z AND
LASTING UNTIL 18Z. SOON AFTER THE SNOW STARTS VSBYS WILL DROP IFR
AND CIGS WILL DROP TO MVFR...AND MAYBE IFR KBGM. THE HEAVIEST SNOW
WILL BE KAVP OF AROUND 2 INCHES WITH 1 TO 2 INCHES THE REST OF THE
SITES. AROUND 18Z VSBYS JUMP BACK TO VFR BUT CIGS WILL REMAIN
MVFR.
LIGHT AND VARIABLE WIND TONIGHT WILL BECOME EAST LATE TONIGHT AT 5
KTS. MIDDAY WINDS BECOME VARIABLE AT 5 KTS.
OUTLOOK...
TUESDAY NIGHT THROUGH WEDNESDAY...RESTRICTIONS POSSIBLE FROM SNOW
SHOWERS.
WEDNESDAY NIGHT THROUGH THURSDAY...BECOMING VFR.
THURSDAY NIGHT THROUGH SATURDAY...RESTRICTIONS POSSIBLE IN RAIN/SNOW
SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY FROM 5 AM TO 5 PM EST TUESDAY FOR
PAZ048.
NY...WINTER WEATHER ADVISORY FROM 5 AM TO 5 PM EST TUESDAY FOR
NYZ062.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...RRM
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
332 AM EST SUN DEC 15 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE UP THE OHIO RIVER
VALLEY...BRINGING SIGNIFICANT SNOWFALL AS IT DEVELOPS INTO A
COASTAL LOW NEAR CAPE COD BY SUNDAY MORNING. SNOWFALL WILL BEGIN
LATE THIS AFTERNOON/EARLY THIS EVENING ACROSS SOUTHERN
AREAS...SPREADING NORTHWARD TONIGHT AND CONTINUING THROUGH MUCH
OF SUNDAY WITH TOTAL ACCUMULATIONS OF 6 TO 12 INCHES LIKELY BY
SUNDAY EVENING. COLD TEMPERATURES CONTINUE INTO THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 933 PM EST SATURDAY...FIRST WIDESPREAD SIGNIFICANT SNOWFALL
OF THE WINTER SEASON HAS BEGIN ACRS THE NORTH COUNTY...WITH CRNT RADAR
SHOWING MODERATE SNOW NOW ENTERING EXTREME SOUTHERN VT. SFC
ANALYSIS PLACES PRIMARY LOW PRES ACRS EASTERN OHIO ATTM...WITH
SECONDARY 1007MB LOW PRES NEAR NORFOLK VA WITH GREATEST 3HR PRE
FALL OF 6MB TWD THE MID ALTANTIC STATES. EXPECT RAPID DEVELOPMENT
OF SFC LOW PRES OVERNIGHT...WITH A GENERAL TRACK TO THE NORTHEAST
TWD NYC ACRS THE CAPE COD CANAL AND INTO THE GULF OF MAINE BY 18Z
SUNDAY. THE LATEST 00Z RAP AND NAM CONTINUE TO SUPPORT THIS IDEA.
THIS WL ALLOW FOR A STRENGTHENING LLVL JET BTWN 925MB AND 850MB TO
DEVELOP...AND ADVECT PLENTY OF ATLANTIC MOISTURE BACK INTO OUR
CWA. ALREADY NOTICING 60 KNOT 85H JET OFF KBGM VAD FROM THE SE.
THE NOSE OF THIS LLVL JET LIFTS FROM EASTERN NY/SOUTHERN NEW
ENGLAND INTO CENTRAL NH/EASTERN VT BY 06Z AND NORTH OF OUR CWA BY
12Z SUNDAY. THIS COMBINED WITH RAP/NAM CONTINUING TO SHOW STRONG
FGEN FORCING/DEEP LAYER UVVS WL PRODUCE A MESO-SCALE BAND OF
MODERATE TO HEAVY SNOW FROM 04Z SOUTHERN VT TO 12Z NORTHERN CWA.
EXPECT VIS BTWN 1/4SM AND 1/2SM IN THIS BAND WITH SNOWFALL RATES
OF 1 TO 2 INCHES PER HOUR. THIS BAND WL CONTINUE TO MOVE AND NOT
BECOMING STATIONARY GIVEN NO CLOSED 5H/7H AND PROGRESSIVE SW TO NE
FLW ALOFT AND FAST MOVEMENT OF SFC LOW PRES. OVERALL...LITTLE
CHANGE IN EXPECTED SNOWFALL WITH A GENERAL 6 TO 12
INCHES...SLIGHTLY HIGHER IN THE FAVORALBE SE UPSLOPE REGIONS AND
SLIGHTLY LESS IN THE DOWNSLOPE REGIONS OF THE NEK/SOUTHERN
CPV...AND PARTS OF THE SLV.
ALSO...EXPECT SFC WIND GUSTS BTWN 30 AND 40 MPH NEAR
RUTLAND/MIDDLEBURY BTWN 04Z-10Z TONIGHT. TEMPS WL SLOWLY RISES
UNDER WAA TO THE MID/UPPER TEENS BY SUNRISE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/...
AS OF 331 PM EST SATURDAY...SFC LOW WILL MOVE INTO THE GULF OF
MAINE AND TOWARD THE CANADIAN MARITIMES ON SUNDAY. BULK OF
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL BEGIN TO DEPART MID-
LATE SUNDAY...TRANSITIONING STEADY SNOWFALL TO SNOW SHOWERS.
THESE SHOWERS WILL LIKELY CONTINUE THROUGH SUNDAY NIGHT ACROSS
THE HIGHER TRRN AS THE PARENT UPPER TROUGH TRACKS THROUGH.
STORM TOTAL SNOWFALL AMOUNTS BY SUNDAY EVENING WILL GENERALLY BE
6-12 INCHES WITH LOCALIZED HIGHER AMOUNTS ACROSS ERN SLOPES DUE
TO SE FLOW TONIGHT INTO SUNDAY MORNING.
TEMPS NOTICEABLY WARMER...BUT SNOWFALL...CLOUDS AND WINDS KEEP
CONDITIONS CHILLY WITH MAX TEMPS IN THE TEENS TO M20S. SUNDAY
NIGHT TEMPS SEE SINGLE DIGITS TEMPS ABOVE AND BELOW ZERO.
ON MONDAY...THE UPPER LOW WILL EXIT THE NORTH COUNTRY TO THE
NE...WITH RIDGING DEVELOPING AT THE SFC AND ALOFT LATE IN THE DAY
INTO MONDAY EVENING. SOME UPSLOPE SNOW ON W-NW FLOW NOT OUT OF
THE QUESTION. WITH SKIES SLOW TO CLEAR AND WINDS OUT OF THE W-NW
AT 10-20 KTS...BLUSTERY CONDITIONS WILL CONTINUE WITH MAX TEMPS
RANGING FROM -5 TO +15 DEGREES FROM STRONG CAA.
MONDAY NIGHT WINDS SHIFT TO THE SOUTH AHEAD OF A CLIPPER TYPE
SYSTEM APPROACHING FROM THE NW. THREAT OF SNOW FROM THIS SYSTEM
WILL INCREASE TOWARDS TUESDAY MORNING FROM THE WEST. ANOTHER COLD
NIGHT...WITH MOST AREAS BEING NEAR OR BELOW ZERO.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 330 AM EST SUNDAY...GOOD MODEL CONSISTENCY SHOWN THRU FRIDAY WITH
MODELS DIVERGING SIGNIFICANTLY THEREAFTER. NO SIGNIFICANT PRECIPITATION
FORECAST WITH TEMPS REMAINING GENERALLY BELOW NORMAL EXCEPT ON
FRIDAY.
A 700-500MB SHORTWAVE TROUGH IS EXPECTED TO TRANSLATE EWD ACROSS THE
NORTHEAST CONUS DURING TUESDAY NIGHT. WEAK SFC LOW WILL REDEVELOP IN
THE GULF OF MAINE BY 12Z WEDNESDAY...BUT IT APPEARS THAT THIS
DEVELOPMENT WILL OCCUR TO LATE/FAR EAST TO HAVE ANY SIGNIFICANT
IMPACT ON THE NORTH COUNTRY. ANTICIPATE CLOUDY CONDITIONS AND
PERIODS OF LIGHT SNOW TUESDAY NIGHT ASSOCIATED WITH UPPER TROUGH AND
DECAYING PRIMARY LOW AS IT SHIFTS EWD ACROSS NRN NY AND VT. LOWS
WILL BE RELATIVELY UNIFORM ACROSS THE FORECAST AREA AND GENERALLY IN
THE TEENS.
LOW AMPLITUDE SHORTWAVE RIDGE AND SFC RIDGE BRING DRY WX CONDITIONS
DURING WEDNESDAY AND WEDNESDAY NIGHT. WINDS WILL BE RELATIVELY
LIGHT. TEMPS WILL REMAIN WELL BELOW SEASONAL LEVELS WITH HIGHS
WEDNESDAY IN THE MID 20S AND LOWS WEDNESDAY NIGHT MAINLY IN THE
TEENS.
PREVAILING MID-TROPOSPHERIC FLOW TRANSITIONS FROM WEST TO SOUTHWEST
WITH WEAK WAVE LOW EXPECTED TO DEVELOP ACROSS THE MID-MS RIVER
VALLEY BEFORE TRACKING TO OUR WEST DURING FRIDAY MORNING. THIS
SHOULD ALLOW FOR SOME MODERATION IN TEMPS THURSDAY AND FRIDAY AS SFC
WINDS BECOME S-SW. HIGHS THURSDAY SHOULD REACH THE UPR 20S AND THEN
MID-UPR 30S ON FRIDAY. LOW PCPN CHANCES UNTIL COLD FRONT SHIFTS
ACROSS THE REGION LATE FRIDAY INTO FRIDAY NIGHT. THIS FEATURE COULD
BRING RAIN/SNOW SHOWERS TRANSITIONING TO SNOW SHOWERS FRIDAY NIGHT.
THE OPERATIONAL 00Z GFS/ECMWF DIVERGE ON SATURDAY. GFS BRINGS STRONG
POLAR HIGH WITH DRY WEATHER FOR SATURDAY AND SUNDAY. ECMWF ALLOWS
THE COLD FRONT FRIDAY NIGHT TO STALL NEAR OR JUST SOUTH OF THE
REGION...WITH POTENTIAL WAVE LOW TRACKING UP ACROSS THE REGION WITH
POSSIBLE WINTRY MIX. PREDICTABILITY IS CONSIDERED LOW ATTM AND
STAYED CLOSER TO THE DRIER 00Z GFS.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
THROUGH 12Z MONDAY...IFR CIGS/VSBY IN SNOW AREAWIDE THRU 18Z WITH
PERIODS OF MODERATE TO BRIEFLY HEAVY SNOW POSSIBLE BTV/PBG/RUT/MPV
THRU ABOUT 13Z SUNDAY. SIGNIFICANT IMPACT TO AVIATION OPERATIONS
EXPECTED THRU 18Z SUNDAY. WIND NOT A MAJOR FACTOR EXCEPT LOCALLY
WITH DOWNSLOPE FLOW AT RUT (SE 20G30KT) AND WITH CHANNELED VALLEY
FLOW AT MSS (NE 12G20KT) THRU 13-14Z SUNDAY. SNOW BECOMES LIGHT
SUNDAY AFTN...BUT ANTICIPATE CONTINUED 2-3SM -SN AT BTV WITH WINDS
TURNING NORTH AND LOCAL TOPOGRAPHIC FORCING THRU 00-02Z MONDAY.
SNOW ENDS DURING SUNDAY NIGHT WITH LINGERING MVFR CEILINGS AND SFC
WINDS GENERALLY NWLY AROUND 10 KTS.
OUTLOOK 12Z MONDAY THROUGH THURSDAY...MAINLY VFR MONDAY AND MOST
OF MONDAY NIGHT AS A RIDGE OF HIGH PRESSURE BUILDS INTO THE
REGION. LIGHT SNOW OR SNOW SHOWERS POSSIBLE DURING TUESDAY NIGHT
INTO EARLY WEDNESDAY WITH MVFR/BRIEF IFR CONDITIONS POSSIBLE. A
SLIGHT CHANCE FOR SOME SNOW SHOWERS ON THURSDAY...BUT MAINLY VFR
CONDITIONS EXPECTED.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
VTZ001>012-016>019.
NY...WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
NYZ026>031-034-035-087.
&&
$$
SYNOPSIS...LAHIFF/KGM
NEAR TERM...TABER
SHORT TERM...KGM
LONG TERM...BANACOS
AVIATION...BANACOS
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1257 AM EST SUN DEC 15 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE UP THE OHIO RIVER
VALLEY...BRINGING SIGNIFICANT SNOWFALL AS IT DEVELOPS INTO A
COASTAL LOW NEAR CAPE COD BY SUNDAY MORNING. SNOWFALL WILL BEGIN
LATE THIS AFTERNOON/EARLY THIS EVENING ACROSS SOUTHERN
AREAS...SPREADING NORTHWARD TONIGHT AND CONTINUING THROUGH MUCH
OF SUNDAY WITH TOTAL ACCUMULATIONS OF 6 TO 12 INCHES LIKELY BY
SUNDAY EVENING. COLD TEMPERATURES CONTINUE INTO THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 933 PM EST SATURDAY...FIRST WIDESPREAD SIGNIFICANT SNOWFALL
OF THE WINTER SEASON HAS BEGIN ACRS THE NORTH COUNTY...WITH CRNT RADAR
SHOWING MODERATE SNOW NOW ENTERING EXTREME SOUTHERN VT. SFC
ANALYSIS PLACES PRIMARY LOW PRES ACRS EASTERN OHIO ATTM...WITH
SECONDARY 1007MB LOW PRES NEAR NORFOLK VA WITH GREATEST 3HR PRE
FALL OF 6MB TWD THE MID ALTANTIC STATES. EXPECT RAPID DEVELOPMENT
OF SFC LOW PRES OVERNIGHT...WITH A GENERAL TRACK TO THE NORTHEAST
TWD NYC ACRS THE CAPE COD CANAL AND INTO THE GULF OF MAINE BY 18Z
SUNDAY. THE LATEST 00Z RAP AND NAM CONTINUE TO SUPPORT THIS IDEA.
THIS WL ALLOW FOR A STRENGTHENING LLVL JET BTWN 925MB AND 850MB TO
DEVELOP...AND ADVECT PLENTY OF ATLANTIC MOISTURE BACK INTO OUR
CWA. ALREADY NOTICING 60 KNOT 85H JET OFF KBGM VAD FROM THE SE.
THE NOSE OF THIS LLVL JET LIFTS FROM EASTERN NY/SOUTHERN NEW
ENGLAND INTO CENTRAL NH/EASTERN VT BY 06Z AND NORTH OF OUR CWA BY
12Z SUNDAY. THIS COMBINED WITH RAP/NAM CONTINUING TO SHOW STRONG
FGEN FORCING/DEEP LAYER UVVS WL PRODUCE A MESO-SCALE BAND OF
MODERATE TO HEAVY SNOW FROM 04Z SOUTHERN VT TO 12Z NORTHERN CWA.
EXPECT VIS BTWN 1/4SM AND 1/2SM IN THIS BAND WITH SNOWFALL RATES
OF 1 TO 2 INCHES PER HOUR. THIS BAND WL CONTINUE TO MOVE AND NOT
BECOMING STATIONARY GIVEN NO CLOSED 5H/7H AND PROGRESSIVE SW TO NE
FLW ALOFT AND FAST MOVEMENT OF SFC LOW PRES. OVERALL...LITTLE
CHANGE IN EXPECTED SNOWFALL WITH A GENERAL 6 TO 12
INCHES...SLIGHTLY HIGHER IN THE FAVORALBE SE UPSLOPE REGIONS AND
SLIGHTLY LESS IN THE DOWNSLOPE REGIONS OF THE NEK/SOUTHERN
CPV...AND PARTS OF THE SLV.
ALSO...EXPECT SFC WIND GUSTS BTWN 30 AND 40 MPH NEAR
RUTLAND/MIDDLEBURY BTWN 04Z-10Z TONIGHT. TEMPS WL SLOWLY RISES
UNDER WAA TO THE MID/UPPER TEENS BY SUNRISE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
AS OF 331 PM EST SATURDAY...SFC LOW WILL MOVE INTO THE GULF OF
MAINE AND TOWARD THE CANADIAN MARITIMES ON SUNDAY. BULK OF
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL BEGIN TO DEPART MID-
LATE SUNDAY...TRANSITIONING STEADY SNOWFALL TO SNOW SHOWERS.
THESE SHOWERS WILL LIKELY CONTINUE THROUGH SUNDAY NIGHT ACROSS
THE HIGHER TRRN AS THE PARENT UPPER TROUGH TRACKS THROUGH.
STORM TOTAL SNOWFALL AMOUNTS BY SUNDAY EVENING WILL GENERALLY BE
6-12 INCHES WITH LOCALIZED HIGHER AMOUNTS ACROSS ERN SLOPES DUE
TO SE FLOW TONIGHT INTO SUNDAY MORNING.
TEMPS NOTICEABLY WARMER...BUT SNOWFALL...CLOUDS AND WINDS KEEP
CONDITIONS CHILLY WITH MAX TEMPS IN THE TEENS TO M20S. SUNDAY
NIGHT TEMPS SEE SINGLE DIGITS TEMPS ABOVE AND BELOW ZERO.
ON MONDAY...THE UPPER LOW WILL EXIT THE NORTH COUNTRY TO THE
NE...WITH RIDGING DEVELOPING AT THE SFC AND ALOFT LATE IN THE DAY
INTO MONDAY EVENING. SOME UPSLOPE SNOW ON W-NW FLOW NOT OUT OF
THE QUESTION. WITH SKIES SLOW TO CLEAR AND WINDS OUT OF THE W-NW
AT 10-20 KTS...BLUSTERY CONDITIONS WILL CONTINUE WITH MAX TEMPS
RANGING FROM -5 TO +15 DEGREES FROM STRONG CAA.
MONDAY NIGHT WINDS SHIFT TO THE SOUTH AHEAD OF A CLIPPER TYPE
SYSTEM APPROACHING FROM THE NW. THREAT OF SNOW FROM THIS SYSTEM
WILL INCREASE TOWARDS TUESDAY MORNING FROM THE WEST. ANOTHER COLD
NIGHT...WITH MOST AREAS BEING NEAR OR BELOW ZERO.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 323 PM EST SATURDAY...SUITE OF GLOBAL DETERMINISTIC AND
ENSEMBLE MEAN SOLUTIONS ARE IN GOOD AGREEMENT THROUGH THURSDAY
NIGHT. MODELS THEN BEGIN TO DIVERGE SIGNIFICANTLY ENOUGH TO LIMIT
PREDICTABILITY FOR THE FRIDAY INTO THE EARLY WEEKEND PERIOD.
AMPLIFICATION OF A 500 MB TROUGH OVER THE GREAT LAKES IS
PREDICTED BY TUESDAY WHICH INDUCES SECONDARY CYCLOGENESIS NEAR
CAPE COD BY TUESDAY NIGHT...WITH THE PROGGED COASTAL MOVING INTO
THE CENTRAL GULF OF MAINE BY WEDNESDAY. I OPTED TO INCREASE POPS
TO HIGH CHANCE/LOW LIKELY FOR TUESDAY INTO TUESDAY NIGHT GIVEN
GOOD CONSISTENCY OVER SEVERAL MODEL CYCLES FOR WHAT WILL BE A
LIGHT-QPF STRATIFORM LIGHT SNOW EVENT FROM INITIAL CLIPPER
SYSTEM. I WAS A LITTLE LEERY OF GOING MUCH HIGHER THAN THAT
THOUGH DUE TO UNCERTAINTIES IN ENERGY TRANSFER TO THE DEVELOPING
COASTAL. THOUGH I DO THINK A DOWNWARD TREND IN POPS ON WEDNESDAY
LOOKS GOOD...I`VE KEPT CHANCE POPS FOR THE NORTHEAST KINGDOM AREA
AS THERE IS SOME INDICATION OF AN INVERTED TROUGH/TROWAL FEATURE
WHICH IF PROGGED CORRECTLY MAY HELP KEEP LIGHT SNOWS GOING A
LITTLE LONGER THERE. TEMPERATURES ARE PRETTY SIMILAR TUESDAY AND
WEDNESDAY...HIGHS GENERALLY IN THE 20S WITH LOWS IN THE TEENS.
A PATTERN CHANGE TOWARD A BRIEF PERIOD OF WARMER WEATHER LOOKS TO
BE IN STORE FOR THE MID TO LATE WEEK PERIOD AS 500 MB HEIGHTS
RISE ACROSS THE EASTERN CONUS. HIGHS ON FRIDAY MAY REACH INTO THE
UPPER 30S TO AROUND 40 IN SPOTS. UNCERTAINTY THEN INCREASES
MARKEDLY DUE TO DIFFERENCES IN HANDLING A LOW MOVING OUT OF THE
MIDWEST TO THE NORTHEAST. THESE DIFFERENCES ARE MOSTLY DUE TO
TIMING THE EJECTION OF AN UPPER-LEVEL TROUGH FRIDAY
AFTERNOON...WHICH IN TURN LEADS TO SOME DISCREPANCY AS TO WHEN
THE ASSOCIATED SFC COLD FRONT PUSHES THROUGH THE NORTH COUNTRY.
ONE THING THAT CAN BE SAID ABOUT THE EARLY WEEKEND PERIOD IS THAT
THE BAROCLINIC ZONE TIED TO THE AFOREMENTIONED COLD FRONT GETS
HUNG UP SOMEWHERE IN THE INTERIOR SOUTHEASTERN CONUS WITH THE
IMPLICATION OF ADDITIONAL CHANCES FOR UNSETTLED WEATHER. IT`S NOT
CLEAR HOW ALL THAT UNFOLDS HOWEVER. I`VE STAYED CLOSE TO THE
SUPERBLEND GUIDANCE FOR THE EARLY WEEKEND PERIOD WHICH OFFERS
CHANCE POPS WITH LOWS TRENDING NEAR TO BELOW NORMAL.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
THROUGH 12Z MONDAY...IFR CIGS/VSBY IN SNOW AREAWIDE THRU 18Z WITH
PERIODS OF MODERATE TO BRIEFLY HEAVY SNOW POSSIBLE BTV/PBG/RUT/MPV
THRU ABOUT 13Z SUNDAY. SIGNIFICANT IMPACT TO AVIATION OPERATIONS
EXPECTED THRU 18Z SUNDAY. WIND NOT A MAJOR FACTOR EXCEPT LOCALLY
WITH DOWNSLOPE FLOW AT RUT (SE 20G30KT) AND WITH CHANNELED VALLEY
FLOW AT MSS (NE 12G20KT) THRU 13-14Z SUNDAY. SNOW BECOMES LIGHT
SUNDAY AFTN...BUT ANTICIPATE CONTINUED 2-3SM -SN AT BTV WITH WINDS
TURNING NORTH AND LOCAL TOPOGRAPHIC FORCING THRU 00-02Z MONDAY.
SNOW ENDS DURING SUNDAY NIGHT WITH LINGERING MVFR CEILINGS AND SFC
WINDS GENERALLY NWLY AROUND 10 KTS.
OUTLOOK 12Z MONDAY THROUGH THURSDAY...MAINLY VFR MONDAY AND MOST
OF MONDAY NIGHT AS A RIDGE OF HIGH PRESSURE BUILDS INTO THE
REGION. LIGHT SNOW OR SNOW SHOWERS POSSIBLE DURING TUESDAY NIGHT
INTO EARLY WEDNESDAY WITH MVFR/BRIEF IFR CONDITIONS POSSIBLE. A
SLIGHT CHANCE FOR SOME SNOW SHOWERS ON THURSDAY...BUT MAINLY VFR
CONDITIONS EXPECTED.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
VTZ001>012-016>019.
NY...WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
NYZ026>031-034-035-087.
&&
$$
SYNOPSIS...LAHIFF/KGM
NEAR TERM...TABER
SHORT TERM...KGM
LONG TERM...LOCONTO
AVIATION...BANACOS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1204 AM EST SUN DEC 15 2013
.SYNOPSIS...
A COASTAL LOW WILL DEEPEN ALONG THE NEW ENGLAND COAST OVERNIGHT AS
LOW PRESSURE TRANSITIONS FROM THE OHIO VALLEY EASTWARD. THIS IS
BRINGING WIDESPREAD ACCUMULATING SNOW TO THE ENTIRE REGION WHICH
WILL TAPER OFF FROM WEST TO EAST EARLY SUNDAY. SOME LINGERING LAKE
EFFECT SNOW WILL CONTINUE LATER SUNDAY AND MONDAY SOUTHEAST OF THE
LAKES. ANOTHER WEAKER LOW PRESSURE WILL BRING ANOTHER ROUND OF SNOW
ON TUESDAY WITH SOME ADDITIONAL LAKE EFFECT SNOW SOUTHEAST OF THE
LAKES WEDNESDAY. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH
MIDWEEK BEFORE MODERATING BY THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
DUAL LOW PRESSURE CENTERS ON THE SURFACE MAP LATE THIS EVENING. ONE
IS NOW CROSSING OVER WESTERN PA WITH THE STRONGER LOW NOW LIFTING
NORTH ACROSS THE DELMARVA PENINSULA. THESE TWO LOWS WILL PHASE INTO
A SINGLE NOREASTER OFF THE NEW JERSEY COAST OVERNIGHT IN A MILLER
TYPE-B COASTAL CYCLOGENESIS. THIS ALWAYS PROVES DIFFICULT FROM A SNOW
ACCUMULATION STANDPOINT AS THE TIMING AND DEGREE OF ENERGY TRANSFER
TO THE COAST CAN IMPACT AMOUNTS TO THE WEST OF THE APPALACHIANS.
TYPICALLY WRAP AROUND PRECIPITATION CAN BE MUCH HEAVIER AS MOISTURE
AND LIFT INCREASE ON THE NORTHWESTERN QUADRANT OF THE SYSTEM WITH
TROWEL FORMATION.
REGIONAL RADAR IMAGERY AND SURFACE OBS SHOWING A DRY SLOT NOW
SHIFTING ACROSS THE FINGER LAKES TOWARD THE EAST AS THE STORM
WRAPS IN DRIER AIR FROM THE SOUTHWEST. THIS DRY SLOT WILL BRING A
SHORT WINDOW WITH A BREAK IN SNOWFALL FROM THE FINGER LAKES TO
CENTRAL NEW YORK. THE LATEST HRRR RUNS SHOW THIS SCENARIO VERY WELL.
ACROSS FAR WESTERN NEW YORK THE WRAP AROUND PRECIP IS NOW SHIFTING
BACK ACROSS THE FORECAST AREA ON THE HEELS OF THE DRY SLOT. THIS
AREA EXHIBITING MORE IN THE WAY OF SYNOPTIC LIFT AND MOISTURE SHOULD
BRING MORE INTENSE SNOWFALL RATES POSSIBLY UP TO AN INCH AN HOUR.
THE QPF AND SNOW FORECASTS WERE UPDATED EARLIER THIS EVENING BASED
THE DRY SLOT WHICH HAS LIKELY CUT BACK ON SNOW TOTALS SOME. THE NEW
FORECAST IS A LITTLE LIGHTER ON SNOW TOTALS MAINLY ACROSS THE
GENESEE VALLEY AND FINGER LAKES WHERE THE DRY SLOT WILL PERSIST
LONGER. EAST OF LAKE ONTARIO SNOW RATES AFTER MIDNIGHT WILL INCREASE
UP TO AND INCH AN HOUR AS THE NOREASTER TAKES SHAPE OFF THE COAST
AND WRAP AROUND MOISTURE INCREASES.
EXPECT STORM TOTALS OF 5-8 INCHES FROM THE GENESEE VALLEY AND
WESTERN FINGER LAKES WITH THE DRY SLOT CONTRIBUTING TO LOWER SNOW
TOTALS. WITH AN INTENSIFYING NOREASTER OVER NIGHT HIGHER AMOUNTS OF
10-14 INCHES CAN BE EXPECTED ACROSS THE NORTH COUNTRY EAST OF LAKE
ONTARIO. ACROSS THE ADVISORY AREA FROM THE BUFFALO AND NIAGARA
REGION DOWN TO THE SOUTHERN TIER...EXPECT TOTALS OF 4-6 INCHES. IT
APPEARS THE COMMA HEAD AND STRONGEST WARM ADVECTION WILL NOT RESIDE
IN THESE AREAS LONG ENOUGH TO PRODUCE WARNING CRITERIA SNOW...WITH A
SOLID TO HIGH END ADVISORY STILL LOOKING MOST LIKELY.
THE SYNOPTIC SNOW WILL BE OVER BY DAYBREAK FROM THE GENESEE VALLEY
WESTWARD...AND WILL END BY MID MORNING EAST OF LAKE ONTARIO. THIS
WILL LEAVE JUST SCATTERED SNOW SHOWERS IN SOME LIMITED WRAP AROUND
MOISTURE. SOME LIMITED LAKE EFFECT SNOW WILL ALSO DEVELOP ESPECIALLY
DURING THE AFTERNOON AS TEMPERATURES ALOFT BEGIN TO DROP.
OFF LAKE ERIE...LAKE INDUCED EQUILIBRIUM LEVELS RISE TO AROUND 7K
FEET BY MID AFTERNOON. EXPECT A HYBRID LAKE EFFECT/UPSLOPE SNOW TO
DEVELOP MAINLY ALONG THE CHAUTAUQUA RIDGE. THIS MAY PRODUCE 2-3
INCHES DURING THE AFTERNOON ACROSS THE HIGHER TERRAIN INLAND FROM
LAKE ERIE.
OFF LAKE ONTARIO...LAKE INDUCED EQUILIBRIUM LEVELS ALSO RISE TO
AROUND 7K FEET BY MID AFTERNOON. EXPECT A BAND OF LAKE EFFECT SNOW
TO DEVELOP ACROSS MAINLY OSWEGO COUNTY TO THE SOUTHERN TUG HILL
DURING THE AFTERNOON WITH 2 TO 4 INCHES POSSIBLE.
TEMPERATURES WILL SLOWLY CLIMB OVERNIGHT INTO THE LOWER TO MID 20S
WITH ONGOING LOW/MID LEVEL WARM ADVECTION. TEMPS WILL THEN STAY
FAIRLY STEADY THROUGH SUNDAY...PERHAPS ONLY CLIMBING A DEGREE OR TWO
THROUGH THE DAY.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
SUNDAY NIGHT WILL TRANSITION FROM THE DAYS SYNOPTIC SNOW BACK TO
LAKE EFFECT SNOW AS COOLER AIR BEHIND THE DEPARTING STORM SYSTEM
SENDS TEMPERATURES AT 850 HPA BACK DOWN TO -16 TO -18C.
OFF LAKE ERIE...A WEST TO NORTHWEST FLOW WILL ORIENT A BAND OF SNOW
ACROSS SOUTHERN ERIE/CHAUTAUQUA AND POINTS INLAND. MOST FAVORABLE
LAKE PARAMETERS WILL BE FOUND EARLY IN THE NIGHT WITH LAKE INDUCED
EQUILIBRIUM LEVELS AROUND 10K FEET AND UPWARD MOTION THROUGH A
SATURATED LOW LEVEL. WITH MOISTURE REMAINING PLENTIFUL THROUGH THE
NIGHT EXPECT A BAND OF SNOW...THAT MIGHT BECOME MORE MULTI BANDED IN
CHARACTERISTICS AS WINDS VEER SOME...TO CONTINUE. ALOFT A CLOSED 500
HPA LOW WILL BEGIN THE PERIOD OVER THE UPPER GREAT LAKES...BUT WILL
QUICKLY SLIDE ACROSS THE EASTERN GREAT LAKES THROUGH THE NIGHT. THIS
FEATURE WILL LIKELY KEEP THE LAKE BAND SHIFTING THROUGH THE NIGHT
AND HOLD ACCUMULATIONS TO ADVISORY RANGE VALUES.
OFF LAKE ONTARIO...A WEST TO NORTHWEST FLOW WILL ALSO BE FOUND WITH
A LAKE BAND FIRST ACROSS THE SOUTHERN TUG HILL...DROPPING SOUTHWARD
TO AREAS SOUTHEAST OF LAKE ONTARIO. WHILE THERE WILL BE SOME
FAVORABLE LAKE PARAMETERS...WITH LAKE INDUCED EQUILIBRIUM LEVELS AND
INVERSION HEIGHTS OVER 10K FEET THE AMOUNT OF MOISTURE IN THE LOWER
LEVELS WILL BE SOMEWHAT LIMITED. NORTHERLY FLOW AROUND THE ATLANTIC
COASTAL LOW WILL DROP SOUTHWARD AND SETTLE TO POINTS AROUND LAKE
ONTARIO...WHICH WILL ALSO PREVENT ANY UPSTREAM LAKE CONNECTION.
EXPECT SNOW TOTALS OFF LAKE ONTARIO TO BE LIGHTER THAN LAKE
ERIE...WITH OVERALL NUMBERS POSSIBLY REMAINING BELOW ADVISORY
LEVELS.
ELSEWHERE MONDAY NIGHT A FEW LIGHT SNOW SHOWERS AND FLURRIES WILL
LIKELY FLY WITH THE PASSAGE OF THE UPPER LEVEL TROUGH. IT WILL
REMAIN COLD SUNDAY NIGHT WITH LOWS DROPPING DOWN INTO THE SINGLE
DIGITS TO LOW DOUBLE DIGITS. THE NORTH COUNTY...IF THEY HAVE SOME
CLEARING STANDS A CHANCE TO BECOME EVEN COLDER THAN FORECASTED.
CURRENT FORECAST MINS JUST BELOW ZERO COULD EASILY REACH -10F OR
COLDER OVER A DEEP AND FRESH SNOW PACK...IF WE GET SOME CLEARING.
FOR NOW BELIEVE THERE MAY BE ENOUGH CLOUDS LINGERING THROUGH THE
NIGHT AHEAD OF THE SHORTWAVE TO PREVENT THESE MUCH COLDER LOWS.
ON MONDAY DRIER AIR BEHIND THE SHORTWAVE WILL BEGIN TO WEAKEN THE
LAKE BANDS. HIGH PRESSURE WILL SCURRY BY TO OUR SOUTH AND INVERSION
HEIGHTS WILL FALL WHICH ALSO WILL PUT A DAMPER ON THE LAKE EFFECT
SNOWS. AS THIS HIGH SLIDES EASTWARD LATER MONDAY AND IN ADVANCE OF
THE NEXT CLIPPER LOW OUR WINDS WILL BACK AROUND TO MORE OF A
SOUTHWESTERLY FLOW. INCREASE WIND SHEAR WILL FURTHER DIMINISH THE
LAKE SNOWS MONDAY NIGHT WHILE SENDING THEM NORTHWARD TOWARDS METRO
BUFFALO OFF LAKE ERIE AND WATERTOWN OFF LAKE ONTARIO.
THERE ARE STILL SOME MODEL TIMING DIFFERENCES WITH THE ARRIVAL OF
THE NEXT AREA OF LOW PRESSURE...ONE THAT WILL DROP ACROSS SOUTHERN
CANADA AND THE UPPER GREAT LAKES...AND THEN NORTH OF LAKE
ONTARIO...BEFORE A COASTAL REDEVELOPMENT TAKES PLACE. THE 12Z ECMWF
AND THE 12Z CMC CONTINUE TO BE FASTER THAN THE GFS MODEL...THOUGH
ALL AGREE THAT A LIGHT GENERAL SNOWFALL ACROSS THE CWA
TUESDAY-TUESDAY NIGHT IS LIKELY. AHEAD OF THE SYSTEM OUR HIGHS WILL
CLIMB INTO THE UPPER 20S...AND MAY EVEN CRACK THE FREEZING MARK FOR
A BRIEF PERIOD OF TIME. WITH THE LINGERING CLOUDS TUESDAY NIGHT WILL
NOT BE AS COLD...WITH LOWS GENERALLY IN THE LOW 20S ACROSS THE CWA.
SNOW WILL TAPER OFF TUESDAY NIGHT BEHIND THE CLIPPER LOW...HOWEVER
AGAIN WE WILL SEE LAKE EFFECT SNOW LINGERING TO THE EAST...AND THEN
SOUTHEAST OF THE LAKES. SHIFTING WINDS AND A RETURN OF HIGH PRESSURE
ON WEDNESDAY WILL LIKELY KEEP SNOW TOTALS ON TUESDAY NIGHT TO
PERHAPS ADVISORY LEVELS OR LOWER.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THROUGH THIS TIME PERIOD OUR FLOW ALOFT WILL GO FROM NORTHWESTERLY
TO A WESTERLY ZONAL FLOW...AND THEN TO A DEEP AMPLIFIED SOUTHWEST
FLOW. THIS WILL ALLOW FROM BELOW NORMAL TEMPERATURES AT THE START OF
THE PERIOD TO WARM TO ABOVE NORMAL AROUND FRIDAY...SOME MODEL
UNCERTAINTY ON THE TIMING OF A COLD FRONT AT THE BEGINNING OF THE
WEEKEND...MAY OR MAY NOT LEAVE SATURDAY ABOVE NORMAL AS WELL.
WILL CONTINUE WITH A CHANCE FOR SOME LIGHT LAKE EFFECT SNOW SHOWERS
SOUTHEAST OF THE LAKES WEDNESDAY AND INTO EARLY WEDNESDAY WITH THE
NORTHWEST FLOW...BUT AS HIGH PRESSURE AT THE SURFACE NUDGES INTO THE
REGION WEDNESDAY NIGHT EXPECT THE LAKE SNOW ACTIVITY TO GREATLY
DIMINISH. THIS MAY LEAVE THURSDAY AS A DRY DAY AS THE FLOW BECOMES
MORE SOUTHWESTERLY IN RESPONSE TO A DIGGING TROUGH ACROSS THE
SOUTHWESTERN US AND BUILDING DOWNSTREAM HEIGHTS ACROSS THE EASTERN
US. WILL BRING A CHANCE FOR RAIN SNOW IN LATER FRIDAY...WITH A COLD
FRONT PASSING ACROSS THE REGION NEXT WEEKEND CHANGING THE RAIN BACK
TO SNOW. THERE IS STILL SOME MODEL UNCERTAINTY TO THE TIMING AND
PLACEMENT OF SURFACE WAVES ALONG THIS COLD FRONT...WHICH WILL IMPACT
THE FRONTAL CROSSING FOR OUR REGION.
&&
.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
KBUF RADAR SHOWING A DRY SLOT IN THE SNOW SHIFTING EAST ACROSS
THE FINGER LAKES TOWARD CENTRAL NEW YORK. WITHIN THIS DRY SLOT BRIEF
VFR CONDITIONS HAVE BEEN OBSERVED. BACK TO THE WEST A SECOND
PERIOD OF HEAVY SNOW IS WORKING BACK ACROSS THE WNY TERMINALS
ASSOCIATED WITH WRAP AROUND MOISTURE FROM A DEVELOPING NOREASTER
TAKING SHAPE NEAR THE MID-ATLANTIC COAST. THIS WRAP AROUND SNOW WILL
BRING BACK IFR/LIFR CONDITIONS THROUGH THE 04Z TO 10Z TIME FRAME
WITH CONDITIONS IMPROVING TO MVFR CIGS IN MOST PLACES WITH SCATTERED
LIGHT SNOW SHOWERS TOMORROW AFTER DAY BREAK. IFR CIGS LOOK TO REMAIN
ACROSS THE SOUTHERN TIER. SOME LIMITED LAKE EFFECT SNOW WILL KEEP
SPOTTY IFR GOING SOUTHEAST OF THE LAKES. MVFR CIGS WILL LIKELY
LINGER IN MOST AREAS THROUGH AT LEAST THE FIRST HALF OF
SUNDAY...WITH SOME IFR ACROSS HIGHER TERRAIN IN THE MORNING.
SUNDAY EVENING INTO THE OVERNIGHT WESTERLY FLOW OVER THE LAKES WILL
DEVELOP SOME LAKE EFFECT SNOW BANDS EAST OF THE GREAT LAKES. THESE
MAY BRING IFR/MVFR TO KJHW AND KART SUNDAY AFTERNOON/EVENING.
OUTLOOK...
MONDAY...LAKE EFFECT SNOW SHOWERS WITH LOCAL IFR SOUTHEAST OF THE
LAKES DIMINISHING.
TUESDAY...SNOW SHOWERS LIKELY WITH AREAS OF MVFR/IFR.
WEDNESDAY...MAINLY VFR WITH A CHANCE OF SNOW SHOWERS...EXCEPT LAKE
EFFECT SNOW SHOWERS LIKELY SOUTHEAST OF THE LAKES WITH LOCAL IFR.
THURSDAY...MAINLY VFR.
&&
.MARINE...
LOW PRESSURE WILL MOVE ALONG THE NY/PA BORDER OVERNIGHT AND GIVE WAY
TO A SECONDARY COASTAL LOW OFF THE MID ATLANTIC COAST. THE PRESSURE
GRADIENT BETWEEN BOTH OF THESE SYSTEMS AND HIGH PRESSURE OVER
SOUTHEAST CANADA WILL MAINTAIN MODERATE NORTHEAST WINDS ON THE LOWER
LAKES. THIS WILL KEEP SMALL CRAFT CONDITIONS GOING ON THE WEST HALF
OF LAKE ONTARIO.
ON SUNDAY AS THE COASTAL LOW DEEPENS WINDS WILL COME AROUND TO THE
NORTHWEST AND EVENTUALLY WEST. THIS WILL BRING SMALL CRAFT ADVISORY
CONDITIONS TO BOTH LAKES ERIE AND ONTARIO...WHICH WILL LAST THROUGH
MONDAY BEFORE HIGH PRESSURE BUILDS OVER THE LOWER LAKES AND ALLOWS
WINDS TO DIMINISH.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER STORM WARNING UNTIL 10 AM EST THIS MORNING FOR
NYZ006>008.
WINTER STORM WARNING UNTIL 9 AM EST THIS MORNING FOR
NYZ002>005-011>014.
WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
NYZ001-010-019>021-085.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 1 PM EST MONDAY FOR
LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 10 AM EST MONDAY FOR
LOZ042-043.
SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 4 PM EST
MONDAY FOR LOZ045.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 4 PM EST
MONDAY FOR LOZ044.
&&
$$
SYNOPSIS...HITCHCOCK/SMITH
NEAR TERM...HITCHCOCK/SMITH
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...HITCHCOCK/SMITH
MARINE...HITCHCOCK/SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
711 PM EST TUE DEC 16 2013
.SYNOPSIS... WEAK HIGH PRESSURE MOVES EAST OF THE STATE TONIGHT
AHEAD OF A COLD FRONT. THIS FRONT CROSSES THE REGION TUESDAY NIGHT.
ANOTHER HIGH THEN BUILDS INTO THE CAROLINAS FROM THE WEST WEDNESDAY.
&&
.NEAR TERM /TONIGHT/...
AS OF 710 PM MONDAY...
THE LATEST WATER VAPOR IMAGERY SHOWED A WELL-DEFINED MID-LEVEL
SHORTWAVE MOVING TOWARD THE STATE FROM THE WEST...AND THIS WAVE WILL
MOVE ACROSS THE STATE THIS EVENING AND THROUGH THE EARLY PART OF THE
OVERNIGHT HOURS WITH AREAS OF MID- AND HIGH-LEVEL CLOUDS AHEAD OF
IT. THE LATEST RAP MID- AND UPPER-LEVEL RELATIVE HUMIDITY
FORECASTS...ALONG WITH THE HRRR WRF CLOUD COVER FORECAST...ARE
HANDLING THE BASIC COVERAGE AND ORIENTATION OF THE EXISTING CLOUDS
WELL...AND AS THE SHORTWAVE MOVES EAST THE CLOUDS...MOSTLY ALONG AND
NORTH OF ABOUT U.S. 64...WILL SHIFT EAST AS WELL. PATCHY HIGH CLOUDS
ARE LOCATED FARTHER UPSTREAM...AND IN THE WEST-TO-NORTHWEST FLOW
ALOFT SOME OF THESE SHOULD WORK THEIR WAY INTO THE NORTHWEST
PIEDMONT LATE TONIGHT. PARTLY CLOUDY THIS EVENING WITH PERIODS OF
MOSTLY CLEAR CONDITIONS OVERNIGHT BASICALLY ALONG AND NORTH OF U.S.
64...BECOMING PARTLY CLOUDY AGAIN LATE TOWARD THE TRIAD. SOUTH OF
ABOUT U.S. 64...MOSTLY CLEAR ON AVERAGE.
SURFACE DEW POINTS IN THE MID 30S TO NEAR 40 OVER A LARGE PART OF
CENTRAL NORTH CAROLINA...EXCEPT THE NORTHWEST PIEDMONT...HAVE
STARTED TO FALL OVER THE LAST HOUR OR TWO IN ACCORDANCE WITH THE RAP
FORECASTS AND MOS GUIDANCE. TEMPERATURES IN SOME AREAS HAVE SHOWN A
RAPID DECLINE...BUT OVERNIGHT THE SURFACE DEW POINTS ARE EXPECTED TO
STABILIZE AND THERE IS FORECAST A GRADUAL INCREASE IN 925MB WINDS AS
THE SURFACE HIGH MOVES OFF TO THE EAST...AND THE GRADIENT STARTS TO
TIGHTEN SOME. THE SURFACE FRONT TO OUR NORTH MAY MOVE A LITTLE
FARTHER NORTH LATE TONIGHT...AND THERE COULD BE JUST ENOUGH STIRRING
OF THE WIND OVERNIGHT AT TIMES TO KEEP TEMPERATURES FROM FALLING
WELL BELOW GUIDANCE. MINS ARE ALREADY FORECAST NEAREST THE COLDER
MAV GUIDANCE AND HAVE CONTINUED THAT FOR THIS FORECAST BASED ON
EXPECTED CLEARING AND THE PACE OF FALLING TEMPERATURES THUS FAR.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 240 PM MONDAY...
THE SURFACE LOW TRACKING EASTWARD THROUGH THE NORTHERN MID-ATLANTIC
STATES WILL EXIT OFFSHORE TUESDAY AFTERNOON...AND WILL DRAG A
SURFACE COLD FRONT THROUGH THE AREA TUESDAY EVENING. UNDER PARTLY TO
MOSTLY SUNNY SKIES...LOW-LEVEL SWLY WARM AIR ADVECTION PRIOR TO THE
ARRIVAL OF THE COLD FRONT WILL ALLOW THICKNESSES TO CLIMB ANOTHER 10
METERS WHICH SHOULD SUPPORT HIGHS IN THE MID 50S NORTH TO AROUND 60
SOUTH.
CAA IN THE WAKE OF THE COLD FRONTAL PASSAGE TUESDAY EVENING WILL
GOVERN OVERNIGHT LOWS...WITH LOW-LEVEL THICKNESSES PROGGED TO FALL
TO AROUND 1280 METERS...35 METERS BELOW NORMAL. OVERNIGHT LOWS IN
THE UPPER 20S NORTH TO LOWER/MID 30S SOUTHEAST.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...
A PROGRESSIVE NORTHERN STREAM SHORT WAVE TROUGH EXITS THE MID
ATLANTIC EARLY ON WEDNESDAY WITH THE FLOW ALOFT BECOMING MORE
WESTERLY ON THURSDAY. A DRY ATMOSPHERE WITH PW VALUES GENERALLY LESS
THAN 0.3 INCHES PROVIDES A HIGH CONFIDENCE FORECAST OF DRY WEATHER
WITH FEW CLOUDS. SLIGHTLY BELOW NORMAL TEMPS ON WEDNESDAY WITH HIGHS
AROUND 50 WILL WARM INTO THE MID 50S TO NEAR 60 BY THURSDAY. LOWS
THURSDAY MORNING WILL RANGE IN THE UPPER 20S TO LOWER 30S.
AN AMPLIFYING TROUGH DIVES SOUTH ALONG THE PACIFIC COAST ON FRIDAY
AS THE FLOW ALOFT OVER CENTRAL NC BECOMES MORE SOUTHWESTERLY. AT THE
SAME TIME SURFACE HIGH PRESSURE OVER THE CAROLINAS SHIFTS OFFSHORE
AND A LOW LEVEL RETURN FLOW DEVELOPS. THE RETURN FLOW WILL ALLOW
SHALLOW MOISTURE TO SPREAD INTO THE REGION...MODERATING MORNING LOWS
ON FRIDAY (IN THE 40-45 RANGE) AND PROVING THE POTENTIAL FOR SOME
MORNING STRATUS THAT WILL MIX INTO SOME AFTERNOON CUMULIFORM CLOUDS
UNDER A CANOPY OF CIRRUS ALOFT. COULD BE AN ISOLATED SHOWER IN THE
WARM SOUTHERLY FLOW BUT THIS PATTERN IS SOMETIMES SLOW TO EVOLVE AND
COVERAGE WILL LIKELY BE LIMITED. GIVEN LOW CONFIDENCE IN
POPS...PREFER TO OMIT RAIN CHANCES ON FRIDAY FOR NOW. HIGHS FRIDAY
AFTERNOON SHOULD CLIMB INTO THE 60S TO NEAR 70 WITH LOWS FRIDAY
NIGHT IN THE LOWER TO MID 50S.
THE PACIFIC TROUGH CLOSES OFF LATE FRIDAY INTO EARLY SATURDAY IN
MEXICO SOUTH OF AZ/NM AND THEN LIFTS NORTHEAST ACROSS THE
CENTRAL/EASTERN U.S. OVER THE WEEKEND INTO MONDAY. THE MAIN ENERGY
WITH THE SYSTEM SLOWLY SHEARS OUT OVER THE MS VALLEY INTO THE
WESTERN OH VALLEY AND GREAT LAKES WITH THE ATTENDANT SURFACE LOW
REMAINING WEST OF THE APPALACHIANS. THE TRAILING COLD FRONT IS LEFT
DANGLING SOUTH OF THE DEPARTING STRONGER FLOW AND SETS UP PARALLEL
TO THE FLOW ALOFT. THIS TYPE OF PATTERN TYPICALLY RESULTS IN A
SLOWER PASSAGE OF THE COLD FRONT AND LESS ROBUST PRECIPITATION
CHANCES. WPC GUIDANCE PREFERS A SLOWER EC ENS MEAN AND HAVE REDUCED
POPS SLIGHTLY BUT MORE SIGNIFICANTLY DELAYED POPS A BIT FOCUSING ON
LATER MONDAY FOR THE BEST CHANCE OF SHOWERS. -BLAES
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 640 PM MONDAY...
VFR CONDITIONS WILL CONTINUE THROUGH THE 00Z VALID TAF PERIOD.
SURFACE DEW POINTS ARE IN THE MID TO UPPER 30S AT KFAY AND KRWI
EARLY THIS EVENING...THOUGH RAP MODEL GUIDANCE SUGGESTS THESE SHOULD
LOWER SOME OVERNIGHT. SREF PROBABILITIES OF SOME LIGHT FOG ARE A
LITTLE HIGHER TOWARD KRWI THAN WAS THE CASE IN MODEL RUNS OF 24
HOURS AGO...BUT WITH ANTICIPATED SLIGHTLY DIMINISHING DEW POINTS AND
MODEST STIRRING OVERNIGHT...HAVE LEFT ANY MVFR CONDITIONS OUT OF ALL
CENTRAL NORTH CAROLINA TAFS. TO AVOID AN OVERLY DETAILED TAF THE
TIMING OF THE WIND GUST FORECAST FOR TUESDAY IS LIKELY A LITTLE
EARLY...BUT DURING THE DAY TUESDAY...ESPECIALLY TUESDAY
AFTERNOON...ANTICIPATE SOUTHWEST WIND GUSTS DEVELOPING FROM 15 TO
20KT.
BEYOND THE 00Z VALID TAF PERIOD...EXPECT DRY VFR CONDITIONS THROUGH
FRIDAY. A STRENGTHENING SOUTHERLY RETURN FLOW COULD LEAD TO SOME
MORNING STRATUS/FOG LATE FRIDAY NIGHT/EARLY SATURDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...DJF/CBL
NEAR TERM...DJF
SHORT TERM...CBL
LONG TERM...BLAES
AVIATION...DJF/CBL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
641 PM EST TUE DEC 16 2013
.SYNOPSIS... WEAK HIGH PRESSURE MOVES EAST OF THE STATE TONIGHT
AHEAD OF A COLD FRONT. THIS FRONT CROSSES THE REGION TUESDAY NIGHT.
ANOTHER HIGH THEN BUILDS INTO THE CAROLINAS FROM THE WEST WEDNESDAY.
&&
.NEAR TERM /TONIGHT/...
AS OF 240 PM MONDAY...
ANOTHER VIGOROUS SHORTWAVE TROUGH OVER SOUTH-CENTRAL CANADA WILL DIG
SOUTHEASTWARD THROUGH THE MID MS VALLEY/OHIO VALLEY TONIGHT AND THEN
INTO THE CENTRAL AND SOUTHERN APPALACHIANS ON TUESDAY...BEFORE
MOVING OFF THE NORTHERN MID ATLANTIC COAST TUESDAY NIGHT. IN
RESPONSE TO THE STRONG UPSTREAM HEIGHT FALLS...A WEAK WAVE OF LOW
PRESSURE WILL DEVELOP OVER THE OHIO VALLEY THIS EVENING AND WILL
PROGRESS EAST THROUGH THE NORTHERN MID-ATLANTIC REGION ON TUESDAY.
UPSTREAM HEIGHT FALLS WILL ALLOW LOW-LEVEL FLOW TO BACK TO SWLY THIS
EVENING AND TONIGHT. RESULTANT WARM AIR ADVECTION MAY RESULT IN A
FEW/SCATTERED MID CLOUDS BUT SKIES SHOULD BE MOSTLY CLEAR FOR THE
FIRST HALF OF THE NIGHT WITH A MARKED INCREASE IN HIGH CLOUDS
LATE(BETWEEN 06-12Z)OWING TO INCREASING UPPER LEVEL DIVERGENCE IN
RESPONSE TO DIGGING UPSTREAM TROUGH. WITH RESIDUAL DRY AIR IN
PLACE...GOOD RADIATIONAL COOLING SHOULD ALLOW TEMPS TO QUICKLY
BOTTOM OUT IN THE UPPER 20S TO LOWER 30S THIS EVENING...WITH
TEMPERATURES THEN WARMING A DEGREE OR TWO AFTER MIDNIGHT WITH THE
INLFUX OF CLOUDS AND A LIGHT SOUTHERLY WIND.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 240 PM MONDAY...
THE AFOREMENTIONED SURFACE LOW TRACKING EASTWARD THROUGH THE
NORTHERN MID-ATLANTIC STATES WILL EXIT OFFSHORE TUESDAY
AFTERNOON...AND WILL DRAG A SURFACE COLD FRONT THROUGH THE AREA
TUESDAY EVENING. UNDER PARTLY TO MOSTLY SUNNY SKIES...LOW-LEVEL SWLY
WARM AIR ADVECTION PRIOR TO THE ARRIVAL OF THE COLD FRONT WILL ALLOW
THICKNESSES TO CLIMB ANOTHER 10 METERS WHICH SHOULD SUPPORT HIGHS IN
THE MID 50S NORTH TO AROUND 60 SOUTH.
CAA IN THE WAKE OF THE COLD FRONTAL PASSAGE TUESDAY EVENING WILL
GOVERN OVERNIGHT LOWS...WITH LOW-LEVEL THICKNESSES PROGGED TO FALL
TO AROUND 1280 METERS...35 METERS BELOW NORMAL. OVERNIGHT LOWS IN
THE UPPER 20S NORTH TO LOWER/MID 30S SOUTHEAST.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...
A PROGRESSIVE NORTHERN STREAM SHORT WAVE TROUGH EXITS THE MID
ATLANTIC EARLY ON WEDNESDAY WITH THE FLOW ALOFT BECOMING MORE
WESTERLY ON THURSDAY. A DRY ATMOSPHERE WITH PW VALUES GENERALLY LESS
THAN 0.3 INCHES PROVIDES A HIGH CONFIDENCE FORECAST OF DRY WEATHER
WITH FEW CLOUDS. SLIGHTLY BELOW NORMAL TEMPS ON WEDNESDAY WITH HIGHS
AROUND 50 WILL WARM INTO THE MID 50S TO NEAR 60 BY THURSDAY. LOWS
THURSDAY MORNING WILL RANGE IN THE UPPER 20S TO LOWER 30S.
AN AMPLIFYING TROUGH DIVES SOUTH ALONG THE PACIFIC COAST ON FRIDAY
AS THE FLOW ALOFT OVER CENTRAL NC BECOMES MORE SOUTHWESTERLY. AT THE
SAME TIME SURFACE HIGH PRESSURE OVER THE CAROLINAS SHIFTS OFFSHORE
AND A LOW LEVEL RETURN FLOW DEVELOPS. THE RETURN FLOW WILL ALLOW
SHALLOW MOISTURE TO SPREAD INTO THE REGION...MODERATING MORNING LOWS
ON FRIDAY (IN THE 40-45 RANGE) AND PROVING THE POTENTIAL FOR SOME
MORNING STRATUS THAT WILL MIX INTO SOME AFTERNOON CUMULIFORM CLOUDS
UNDER A CANOPY OF CIRRUS ALOFT. COULD BE AN ISOLATED SHOWER IN THE
WARM SOUTHERLY FLOW BUT THIS PATTERN IS SOMETIMES SLOW TO EVOLVE AND
COVERAGE WILL LIKELY BE LIMITED. GIVEN LOW CONFIDENCE IN
POPS...PREFER TO OMIT RAIN CHANCES ON FRIDAY FOR NOW. HIGHS FRIDAY
AFTERNOON SHOULD CLIMB INTO THE 60S TO NEAR 70 WITH LOWS FRIDAY
NIGHT IN THE LOWER TO MID 50S.
THE PACIFIC TROUGH CLOSES OFF LATE FRIDAY INTO EARLY SATURDAY IN
MEXICO SOUTH OF AZ/NM AND THEN LIFTS NORTHEAST ACROSS THE
CENTRAL/EASTERN U.S. OVER THE WEEKEND INTO MONDAY. THE MAIN ENERGY
WITH THE SYSTEM SLOWLY SHEARS OUT OVER THE MS VALLEY INTO THE
WESTERN OH VALLEY AND GREAT LAKES WITH THE ATTENDANT SURFACE LOW
REMAINING WEST OF THE APPALACHIANS. THE TRAILING COLD FRONT IS LEFT
DANGLING SOUTH OF THE DEPARTING STRONGER FLOW AND SETS UP PARALLEL
TO THE FLOW ALOFT. THIS TYPE OF PATTERN TYPICALLY RESULTS IN A
SLOWER PASSAGE OF THE COLD FRONT AND LESS ROBUST PRECIPITATION
CHANCES. WPC GUIDANCE PREFERS A SLOWER EC ENS MEAN AND HAVE REDUCED
POPS SLIGHTLY BUT MORE SIGNIFICANTLY DELAYED POPS A BIT FOCUSING ON
LATER MONDAY FOR THE BEST CHANCE OF SHOWERS. -BLAES
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 640 PM MONDAY...
VFR CONDITIONS WILL CONTINUE THROUGH THE 00Z VALID TAF PERIOD.
SURFACE DEW POINTS ARE IN THE MID TO UPPER 30S AT KFAY AND KRWI
EARLY THIS EVENING...THOUGH RAP MODEL GUIDANCE SUGGESTS THESE SHOULD
LOWER SOME OVERNIGHT. SREF PROBABILITIES OF SOME LIGHT FOG ARE A
LITTLE HIGHER TOWARD KRWI THAN WAS THE CASE IN MODEL RUNS OF 24
HOURS AGO...BUT WITH ANTICIPATED SLIGHTLY DIMINISHING DEW POINTS AND
MODEST STIRRING OVERNIGHT...HAVE LEFT ANY MVFR CONDITIONS OUT OF ALL
CENTRAL NORTH CAROLINA TAFS. TO AVOID AN OVERLY DETAILED TAF THE
TIMING OF THE WIND GUST FORECAST FOR TUESDAY IS LIKELY A LITTLE
EARLY...BUT DURING THE DAY TUESDAY...ESPECIALLY TUESDAY
AFTERNOON...ANTICIPATE SOUTHWEST WIND GUSTS DEVELOPING FROM 15 TO
20KT.
BEYOND THE 00Z VALID TAF PERIOD...EXPECT DRY VFR CONDITIONS THROUGH
FRIDAY. A STRENGTHENING SOUTHERLY RETURN FLOW COULD LEAD TO SOME
MORNING STRATUS/FOG LATE FRIDAY NIGHT/EARLY SATURDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...DJF/CBL
NEAR TERM...CBL
SHORT TERM...CBL
LONG TERM...BLAES
AVIATION...DJF/CBL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1245 PM EST SUN DEC 15 2013
.SYNOPSIS...HIGH PRESSURE BUILDS OVER THE REGION INTO MONDAY. A
COLD FRONT MOVES THROUGH THE REGION TUESDAY. HIGH PRESSURE RETURNS
FOR WEDNESDAY AND THURSDAY ALONG WITH A WARMING TREND.
&&
.NEAR TERM /TODAY THROUGH TONIGHT/...
AS OF 940 AM SUNDAY...
CLOUDS HAVE BEEN A LITTLE SLOW TO ERODE THIS MORNING...WITH THE
LATEST SATELLITE IMAGES SHOWING CLEARING BEGINNING ALONG AND WEST OF
U.S. 1...AND ONLY A FEW THIN PATCHES TO THE EAST OF THERE. THE 06Z
GFS WAS LIKELY A LITTLE TOO AGGRESSIVE WITH DRYING AND CLEARING ON
ITS MODEL SOUNDINGS...AND THE LATEST RAP IN COMBINATION WITH THE
HRRR WRF AND THE LAV SEEMS TO BE DOING FAIRLY WELL WITH THE TREND OF
THE CLEARING. WITH THE FAST SOUTHWEST FLOW ALOFT DELAYING THE MID-
LEVEL DRYING AND BETTER MIXING AS THE 850MB FRONT PASSES...IT MAY BE
EARLY AFTERNOON BEFORE BETTER SUNSHINE STARTS TO BE NOTED TOWARD THE
FAR SOUTHEAST AREAS PARTICULARLY TOWARD KCTZ. EVEN WITH THE DELAY IN
CLEARING...THOUGH...WITH TEMPERATURES IN THE FAR SOUTHEAST ALREADY
CLOSE TO 50 DEGREES IT SHOULD NOT TAKE MUCH SUNSHINE TO REALIZE
FORECAST MAXIMUMS. THERE SHOULD BE A FEW WIND GUSTS OF 20 TO 25 MPH
ESPECIALLY AS MIXING DEVELOPS IN THE NORTHWEST PIEDMONT...LESSER
GUSTS FARTHER SOUTHEAST DUE TO LATER ARRIVAL OF CLEARING AND THE
TIMING OF DIMINISHING 925MB WINDS...TO 15 TO 20KT BY EARLY
AFTERNOON. -DJF
FOR TONIGHT...AS THE MID LEVEL TROUGH AXIS MOVES TO OUR EAST...A
PORTION OF THE SURFACE HIGH NOSES IN FROM THE SW...ENSURING
CONTINUED DRY AND STABLE LOW LEVELS...WHILE SUBSIDENCE CONTINUES
ALOFT. THESE LIGHT SURFACE WINDS ALONG WITH MOSTLY CLEAR SKIES AND
COLD AIR ADVECTION WILL FACILITATE RADIATIONAL COOLING. LOWS 26-32.
-GIH
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 250 AM SUNDAY...
EXPECT DRY AND GENERALLY QUIET WEATHER... ALTHOUGH IT MAY NOT BE
QUITE AS SUN-FILLED AS ONCE THOUGHT ACROSS NRN NC. A WEAK MID LEVEL
WAVE NOW OVER ALBERTA/MT WILL DIVE SE THEN EAST ACROSS THE
MIDATLANTIC/NC MONDAY... WITH A 100+ KT UPPER JET STREAKING INTO THE
REGION. MODEL FORECAST SOUNDINGS SHOW A SOMEWHAT MOIST LAYER BETWEEN
800 MB AND 600 MB OVER THE NRN HALF OF THE CWA... ANDHIGH PRESSURE
BUILDS OVER THE REGION TODAY INTO MONDAY. A MOSTLY DRY COLD FRONT
MOVES THROUGH THE REGION TUESDAY. HIGH PRESSURE RETURNS FOR
WEDNESDAY AND THURSDAY ALONG WITH A WARMING TREND. GIVEN THAT THE
EXPECTED VERTICAL THERMAL AND MOISTURE STRUCTURE WILL BE SUPPORTIVE
OF OROGRAPHIC ENHANCEMENT OF MID-HIGH CLOUDS IN THIS AREA... WILL
HAVE A FORECAST OF SKIES BECOMING PARTLY CLOUDY ROUGHLY ALONG/NORTH
OF HIGHWAY 64 FOR THE AFTERNOON THROUGH MID EVENING... FOLLOWED BY
CLEARING OVERNIGHT AS THE VORTICITY MAX MOVES TO OUR EAST.
THICKNESSES WILL BE ABOUT 15-20 M BELOW NORMAL... SUGGESTING HIGHS
FROM 47 NORTH TO 53 SOUTH WHEN FACTORING IN THE CLOUDS OVER THE
NORTH. LOWS 28-35 WITH SKIES BECOMING MOSTLY CLEAR. -GIH
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 320 AM SUNDAY...
TUESDAY-WEDNESDAY NIGHT: DRY CONDITIONS AND NEAR NORMAL TEMPS.
EXPECT SOME DEGREE OF WARMING ON TUE (HIGHS MID/UPPER 50S) VIA
SOUTHWEST LOW-LEVEL FLOW AND WARM ADVECTION ASSOC/W A TIGHTENING
MSLP/HEIGHT GRADIENT IN ADVANCE OF A POTENT SHORTWAVE AND ATTENDANT
CLIPPER LOW DIGGING INTO THE GREAT LAKES. THE AFOREMENTIONED
SHORTWAVE ENERGY WILL PROGRESS INTO THE NORTHERN MID-ATLANTIC AND
NEW ENGLAND TUE NIGHT BEFORE MOVING OFFSHORE EARLY WED. THE
GFS/ECMWF GUIDANCE ARE ROUGHLY IN GOOD AGREEMENT ON THE EVOLUTION OF
THE AFOREMENTIONED SHORTWAVE ENERGY/CLIPPER SYSTEM...INDICATING A
WEAK/DRY COLD FRONTAL PASSAGE TUE EVE/NIGHT FOLLOWED BY WEAK HIGH
PRESSURE BUILDING INTO THE REGION ON WED. EXPECT LOWS IN THE LOWER
TO MID 30S WED MORNING (COOLEST N/NW)...WITH HIGHS ON WED SEVERAL
DEGREES COOLER THAN TUE IN THE LOWER 50S FAR NORTH TO MID/UPPER 50S
FAR SOUTH. WITH CLEAR SKIES...LIGHT/CALM WINDS AND A DRY AIRMASS IN
PLACE...EXPECT GOOD RADIATIONAL COOLING WITH LOWS IN THE UPPER 20S
TO LOWER 30S WED NIGHT.
THURSDAY-FRIDAY...EXPECT A WARMING TREND WITH INCREASING CLOUD
COVER. SHORTWAVE ENERGY IS EXPECTED TO DIG SOUTHEAST THROUGH THE
NORTHERN ROCKIES INTO THE UPPER MIDWEST THU/THU NIGHT... WITH AN
ATTENDANT SFC LOW TRACKING NE FROM THE CENTRAL PLAINS TO THE GREAT
LAKES AND AN ASSOCIATED COLD FRONT PROGRESSING EAST ACROSS THE MS
RIVER VALLEY. HIGH PRESSURE WILL MOVE OFFSHORE THE CAROLINA COAST IN
ADVANCE OF THE AFOREMENTIONED FRONT ON THU...RESULTING IN THE ONSET
OF SOUTHERLY RETURN FLOW /WARM ADVECTION/. WARM ADVECTION AND LOW-
LEVEL MOISTURE TRANSPORT WILL STRENGTHEN ON FRIDAY AS THE
AFOREMENTIONED FRONT PROGRESSES INTO THE TN/OH VALLEY AND THE
MSLP/HEIGHT GRADIENT TIGHTENS OVER THE CAROLINAS. EXPECT HIGHS IN
THE UPPER 50S TO NEAR 60F (S) ON THU...AND IN THE MID/UPPER 60S TO
NEAR 70F ON FRIDAY DEPENDING ON CLOUD COVER...WARMEST S/SE. THOUGH
LOW-LEVEL WARM ADVECTION (ALONE OR) IN THE PRESENCE OF ANY SMALL
AMPLITUDE DISTURBANCES IN WSW FLOW ALOFT COULD CONCEIVABLY RESULT IN
A LOW CHANCE FOR SPRINKLES OR LIGHT RAIN THU NIGHT/FRI MORNING...
WILL KEEP THE FCST DRY AT THIS TIME.
FRIDAY NIGHT-SATURDAY: UNCERTAINTY IN THE FORECAST INCREASES
DRAMATICALLY THIS WEEKEND WITH REGARD TO THE EVOLUTION OF A COMPLEX
UPPER LEVEL PATTERN CHARACTERIZED BY SPLIT FLOW. REGARDLESS...THE
OVERALL PATTERN WOULD SUGGEST AN ABOVE AVERAGE CHANCE FOR RAIN
ASSOC/W AN INCREASINGLY WARM/MOIST AIRMASS AND THE FRONTAL ZONE
APPROACHING FROM THE WEST. WILL INDICATE MOSTLY CLOUDY/OVERCAST
SKIES AND A 30% CHANCE OF RAIN ON SAT/SUN. -VINCENT
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 1245 PM SUNDAY...
VFR CONDITIONS ARE ANTICIPATED THROUGH THE 18Z VALID TAF PERIOD.
AFTER THE RAIN OF SATURDAY INTO SATURDAY NIGHT...SOME CONCERN ABOUT
THE POTENTIAL FOR MVFR FOG GIVEN THE LOW-LEVEL MOISTURE AND THE SLOW-
TO-FALL DEW POINTS DURING THE DAY ESPECIALLY TOWARD KFAY AND KRWI.
HOWEVER...THE SREF PROBABILITIES OF NEAR IFR VISIBILITIES BARELY
REGISTER...AND IT WOULD APPEAR DRIER AIR IS ON ITS WAY WITH DEW
POINTS FALLING OVER THE NORTHWEST PIEDMONT. LEFT ANY MVFR
VISIBILITIES OUT OF THE TAF FOR THE 18Z ISSUANCE...THINKING MOISTURE
WITH FALLING DEW POINTS MAY TRANSLATE MORE INTO DEW/FROST ON THE
GRASSY SURFACES AS OPPOSED TO LIGHT FOG. WINDS GRADUALLY BACK DURING
MONDAY MORNING UNDER 10KT...WITH A FEW MID-LEVEL CLOUDS MOVING INTO
THE NORTHWEST PIEDMONT THEN.
BEYOND THE 18Z VALID TAF PERIOD...VFR CONDITIONS ARE EXPECTED
THROUGH THE MIDDLE OF THE WEEK. LATE IN THE WEEK...AS THE SOUTHERLY
FLOW INCREASES OVER THE SOUTHEAST STATES...THE BOUNDARY LAYER
MOISTURE SHOULD GRADUALLY INCREASE. THIS COULD HELP LEAD TO SOME
LATE NIGHT AND EARLY MORNING LOW CLOUDS POSSIBLY AS EARLY AS
FRIDAY...MAYBE MORE LIKELY JUST BEYOND THIS DISCUSSION PERIOD INTO
SATURDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF/HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...VINCENT
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
940 AM EST SUN DEC 15 2013
.SYNOPSIS...HIGH PRESSURE BUILDS OVER THE REGION TODAY INTO MONDAY.
A MOSTLY DRY COLD FRONT MOVES THROUGH THE REGION TUESDAY. HIGH
PRESSURE RETURNS FOR WEDNESDAY AND THURSDAY ALONG WITH A WARMING
TREND.
&&
.NEAR TERM /TODAY THROUGH TONIGHT/...
AS OF 940 AM SUNDAY...
CLOUDS HAVE BEEN A LITTLE SLOW TO ERODE THIS MORNING...WITH THE
LATEST SATELLITE IMAGES SHOWING CLEARING BEGINNING ALONG AND WEST OF
U.S. 1...AND ONLY A FEW THIN PATCHES TO THE EAST OF THERE. THE 06Z
GFS WAS LIKELY A LITTLE TOO AGGRESSIVE WITH DRYING AND CLEARING ON
ITS MODEL SOUNDINGS...AND THE LATEST RAP IN COMBINATION WITH THE
HRRR WRF AND THE LAV SEEMS TO BE DOING FAIRLY WELL WITH THE TREND OF
THE CLEARING. WITH THE FAST SOUTHWEST FLOW ALOFT DELAYING THE MID-
LEVEL DRYING AND BETTER MIXING AS THE 850MB FRONT PASSES...IT MAY BE
EARLY AFTERNOON BEFORE BETTER SUNSHINE STARTS TO BE NOTED TOWARD THE
FAR SOUTHEAST AREAS PARTICULARLY TOWARD KCTZ. EVEN WITH THE DELAY IN
CLEARING...THOUGH...WITH TEMPERATURES IN THE FAR SOUTHEAST ALREADY
CLOSE TO 50 DEGREES IT SHOULD NOT TAKE MUCH SUNSHINE TO REALIZE
FORECAST MAXIMUMS. THERE SHOULD BE A FEW WIND GUSTS OF 20 TO 25 MPH
ESPECIALLY AS MIXING DEVELOPS IN THE NORTHWEST PIEDMONT...LESSER
GUSTS FARTHER SOUTHEAST DUE TO LATER ARRIVAL OF CLEARING AND THE
TIMING OF DIMINISHING 925MB WINDS...TO 15 TO 20KT BY EARLY
AFTERNOON. -DJF
FOR TONIGHT...AS THE MID LEVEL TROUGH AXIS MOVES TO OUR EAST...A
PORTION OF THE SURFACE HIGH NOSES IN FROM THE SW...ENSURING
CONTINUED DRY AND STABLE LOW LEVELS...WHILE SUBSIDENCE CONTINUES
ALOFT. THESE LIGHT SURFACE WINDS ALONG WITH MOSTLY CLEAR SKIES AND
COLD AIR ADVECTION WILL FACILITATE RADIATIONAL COOLING. LOWS 26-32.
-GIH
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 250 AM SUNDAY...
EXPECT DRY AND GENERALLY QUIET WEATHER... ALTHOUGH IT MAY NOT BE
QUITE AS SUN-FILLED AS ONCE THOUGHT ACROSS NRN NC. A WEAK MID LEVEL
WAVE NOW OVER ALBERTA/MT WILL DIVE SE THEN EAST ACROSS THE
MIDATLANTIC/NC MONDAY... WITH A 100+ KT UPPER JET STREAKING INTO THE
REGION. MODEL FORECAST SOUNDINGS SHOW A SOMEWHAT MOIST LAYER BETWEEN
800 MB AND 600 MB OVER THE NRN HALF OF THE CWA... AND GIVEN THAT THE
EXPECTED VERTICAL THERMAL AND MOISTURE STRUCTURE WILL BE SUPPORTIVE
OF OROGRAPHIC ENHANCEMENT OF MID-HIGH CLOUDS IN THIS AREA... WILL
HAVE A FORECAST OF SKIES BECOMING PARTLY CLOUDY ROUGHLY ALONG/NORTH
OF HIGHWAY 64 FOR THE AFTERNOON THROUGH MID EVENING... FOLLOWED BY
CLEARING OVERNIGHT AS THE VORTICITY MAX MOVES TO OUR EAST.
THICKNESSES WILL BE ABOUT 15-20 M BELOW NORMAL... SUGGESTING HIGHS
FROM 47 NORTH TO 53 SOUTH WHEN FACTORING IN THE CLOUDS OVER THE
NORTH. LOWS 28-35 WITH SKIES BECOMING MOSTLY CLEAR. -GIH
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 320 AM SUNDAY...
TUESDAY-WEDNESDAY NIGHT: DRY CONDITIONS AND NEAR NORMAL TEMPS.
EXPECT SOME DEGREE OF WARMING ON TUE (HIGHS MID/UPPER 50S) VIA
SOUTHWEST LOW-LEVEL FLOW AND WARM ADVECTION ASSOC/W A TIGHTENING
MSLP/HEIGHT GRADIENT IN ADVANCE OF A POTENT SHORTWAVE AND ATTENDANT
CLIPPER LOW DIGGING INTO THE GREAT LAKES. THE AFOREMENTIONED
SHORTWAVE ENERGY WILL PROGRESS INTO THE NORTHERN MID-ATLANTIC AND
NEW ENGLAND TUE NIGHT BEFORE MOVING OFFSHORE EARLY WED. THE
GFS/ECMWF GUIDANCE ARE ROUGHLY IN GOOD AGREEMENT ON THE EVOLUTION OF
THE AFOREMENTIONED SHORTWAVE ENERGY/CLIPPER SYSTEM...INDICATING A
WEAK/DRY COLD FRONTAL PASSAGE TUE EVE/NIGHT FOLLOWED BY WEAK HIGH
PRESSURE BUILDING INTO THE REGION ON WED. EXPECT LOWS IN THE LOWER
TO MID 30S WED MORNING (COOLEST N/NW)...WITH HIGHS ON WED SEVERAL
DEGREES COOLER THAN TUE IN THE LOWER 50S FAR NORTH TO MID/UPPER 50S
FAR SOUTH. WITH CLEAR SKIES...LIGHT/CALM WINDS AND A DRY AIRMASS IN
PLACE...EXPECT GOOD RADIATIONAL COOLING WITH LOWS IN THE UPPER 20S
TO LOWER 30S WED NIGHT.
THURSDAY-FRIDAY...EXPECT A WARMING TREND WITH INCREASING CLOUD
COVER. SHORTWAVE ENERGY IS EXPECTED TO DIG SOUTHEAST THROUGH THE
NORTHERN ROCKIES INTO THE UPPER MIDWEST THU/THU NIGHT... WITH AN
ATTENDANT SFC LOW TRACKING NE FROM THE CENTRAL PLAINS TO THE GREAT
LAKES AND AN ASSOCIATED COLD FRONT PROGRESSING EAST ACROSS THE MS
RIVER VALLEY. HIGH PRESSURE WILL MOVE OFFSHORE THE CAROLINA COAST IN
ADVANCE OF THE AFOREMENTIONED FRONT ON THU...RESULTING IN THE ONSET
OF SOUTHERLY RETURN FLOW /WARM ADVECTION/. WARM ADVECTION AND LOW-
LEVEL MOISTURE TRANSPORT WILL STRENGTHEN ON FRIDAY AS THE
AFOREMENTIONED FRONT PROGRESSES INTO THE TN/OH VALLEY AND THE
MSLP/HEIGHT GRADIENT TIGHTENS OVER THE CAROLINAS. EXPECT HIGHS IN
THE UPPER 50S TO NEAR 60F (S) ON THU...AND IN THE MID/UPPER 60S TO
NEAR 70F ON FRIDAY DEPENDING ON CLOUD COVER...WARMEST S/SE. THOUGH
LOW-LEVEL WARM ADVECTION (ALONE OR) IN THE PRESENCE OF ANY SMALL
AMPLITUDE DISTURBANCES IN WSW FLOW ALOFT COULD CONCEIVABLY RESULT IN
A LOW CHANCE FOR SPRINKLES OR LIGHT RAIN THU NIGHT/FRI MORNING...
WILL KEEP THE FCST DRY AT THIS TIME.
FRIDAY NIGHT-SATURDAY: UNCERTAINTY IN THE FORECAST INCREASES
DRAMATICALLY THIS WEEKEND WITH REGARD TO THE EVOLUTION OF A COMPLEX
UPPER LEVEL PATTERN CHARACTERIZED BY SPLIT FLOW. REGARDLESS...THE
OVERALL PATTERN WOULD SUGGEST AN ABOVE AVERAGE CHANCE FOR RAIN
ASSOC/W AN INCREASINGLY WARM/MOIST AIRMASS AND THE FRONTAL ZONE
APPROACHING FROM THE WEST. WILL INDICATE MOSTLY CLOUDY/OVERCAST
SKIES AND A 30% CHANCE OF RAIN ON SAT/SUN. -VINCENT
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
AS OF 940 AM SUNDAY...
CONDITIONS WILL SLOWLY IMPROVE FROM NORTHWEST TO SOUTHEAST TO
VFR...WITH THE LATEST IMPROVEMENT TOWARD KFAY BY EARLY AFTERNOON.
LOW LEVEL WINDS WILL BECOME FROM THE WNW OR NW (FROM 270-320
DEGREES) AND WILL INCREASE IN SPEED TO 8-12 KTS OCCASIONALLY GUSTING
TO 18-22 KTS LATE MORNING THROUGH AFTERNOON...HIGHEST GUSTS TOWARD
THE TRIAD. THIS DOWNSLOPE DRYING FLOW WILL SCOUR OUT THE LOW
CLOUDS...THUS...CONFIDENCE IS HIGH IN VFR CONDITIONS AT ALL
SITES...EVEN KFAY...BY MID AFTERNOON. WINDS WILL DIMINISH TO 8 KTS
OR LESS AROUND SUNSET. CLEAR SKIES AND VFR VSBYS ARE EXPECTED
TONIGHT AS HIGH PRESSURE NOSES INTO THE AREA.
LOOKING BEYOND 12Z MONDAY MORNING...HIGH CONFIDENCE IN VFR
CONDITIONS MONDAY THROUGH THURSDAY...AS SURFACE HIGH PRESSURE
DOMINATES WITH DRY WEATHER.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF/HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...VINCENT
AVIATION...DJF/HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
622 AM EST SUN DEC 15 2013
.SYNOPSIS...AN UPPER LEVEL DISTURBANCE WILL CROSS THE CAROLINAS THIS
MORNING. HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE SOUTHWEST
THIS AFTERNOON THROUGH MID WEEK... PROVIDING FAIR AND DRY WEATHER.
THIS HIGH WILL SHIFT OFF THE COAST WEDNESDAY... BRINGING A WARMING
TREND THROUGH LATE WEEK.
&&
NEAR TERM /TODAY THROUGH TONIGHT/...
AS OF 215 AM SUNDAY...
THROUGH TODAY: GREATLY IMPROVING WEATHER IS EXPECTED THIS MORNING.
THE LATEST SURFACE MAP SHOWS THE WEDGE FRONT HAVING MOVED JUST EAST
OF THE CWA... WHILE THE PRIMARY OCCLUDED FRONT HAS MOVED INTO THE NC
MOUNTAINS. WE REMAIN ON THE EAST SIDE OF THE APPROACHING BROAD
TROUGH... AND WHILE THE HEAVIEST RAIN HAS SHIFTED OFF THE COAST... A
POCKET OF MID LEVEL VORTICITY SHEARING OUT OF THE TROUGH BASE ACROSS
THE CENTRAL CAROLINAS IS RESPONSIBLE FOR A BATCH OF MOSTLY LIGHT
RAIN STREAMING OVER THE AREA. THE LATEST HRRR GUIDANCE DEPICTS THIS
PRECIP WELL AND SHOWS THIS LIGHT RAIN AREA PUSHING EASTWARD OUT OF
THE CWA BETWEEN 8 AM AND 10 AM AS THE MID LEVEL TROUGH AXIS CROSSES
THE AREA. THICK LOW CLOUDS WILL PERSIST UNTIL THEN... AS WE`RE
SEEING COOLING AT THE SURFACE BUT THE 925 MB/850 MB TROUGH AXES ARE
STILL TO OUR WEST... YIELDING A VERTICAL THERMAL DIFFERENTIAL AND
FOSTERING LOW LEVEL STABILIZATION (EXACERBATED BY A LOOSE MSLP
GRADIENT AND LIGHT SURFACE WINDS)... HINDERING MIXING. AFTER THE
OCCLUDED FRONT PASSES THROUGH BY MID TO LATE MORNING... THE ENSUING
DOWNSLOPE LOW LEVEL FLOW WILL HELP DRY OUT THE LOWER TROPOSPHERE...
WHILE INCREASING DEEP LAYER SUBSIDENCE IN THE WAKE OF THE DEPARTING
BROAD TROUGH AXIS HELPS DRY AND STABILIZE THE MID-UPPER LEVELS.
EXPECT PLENTY OF SUNSHINE BY THE AFTERNOON HOURS. THICKNESSES DO
FALL DURING THE DAY (MUCH OF WHICH IS A FUNCTION OF COOLING AT 925-
850 MB WITH GOOD DRYING BUT NOT A LOT OF COOLING BELOW 925 MB)...
BUT THE INCOMING AIR MASS IS MODIFIED AND SOURCED FROM OUR WSW...
AND LATE-DAY THICKNESSES ARE STILL JUST SLIGHTLY BELOW NORMAL. HIGHS
49-57... NEAR TO SLIGHTLY UNDER SEASONAL NORMALS. EXPECT BREEZY WNW
WINDS WITH OCCASIONAL GUSTS AS THE COOLER AND MORE DENSE AIR ARRIVES
WITH SHALLOW BUT PRONOUNCED MIXING.
FOR TONIGHT: AS THE MID LEVEL TROUGH AXIS MOVES TO OUR EAST... A
PORTION OF THE SURFACE HIGH NOSES IN FROM THE SW... ENSURING
CONTINUED DRY AND STABLE LOW LEVELS... WHILE SUBSIDENCE CONTINUES
ALOFT. THESE LIGHT SURFACE WINDS ALONG WITH MOSTLY CLEAR SKIES AND
COLD AIR ADVECTION WILL FACILITATE RADIATIONAL COOLING. LOWS 26-32.
-GIH
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 250 AM SUNDAY...
EXPECT DRY AND GENERALLY QUIET WEATHER... ALTHOUGH IT MAY NOT BE
QUITE AS SUN-FILLED AS ONCE THOUGHT ACROSS NRN NC. A WEAK MID LEVEL
WAVE NOW OVER ALBERTA/MT WILL DIVE SE THEN EAST ACROSS THE
MIDATLANTIC/NC MONDAY... WITH A 100+ KT UPPER JET STREAKING INTO THE
REGION. MODEL FORECAST SOUNDINGS SHOW A SOMEWHAT MOIST LAYER BETWEEN
800 MB AND 600 MB OVER THE NRN HALF OF THE CWA... AND GIVEN THAT THE
EXPECTED VERTICAL THERMAL AND MOISTURE STRUCTURE WILL BE SUPPORTIVE
OF OROGRAPHIC ENHANCEMENT OF MID-HIGH CLOUDS IN THIS AREA... WILL
HAVE A FORECAST OF SKIES BECOMING PARTLY CLOUDY ROUGHLY ALONG/NORTH
OF HIGHWAY 64 FOR THE AFTERNOON THROUGH MID EVENING... FOLLOWED BY
CLEARING OVERNIGHT AS THE VORTICITY MAX MOVES TO OUR EAST.
THICKNESSES WILL BE ABOUT 15-20 M BELOW NORMAL... SUGGESTING HIGHS
FROM 47 NORTH TO 53 SOUTH WHEN FACTORING IN THE CLOUDS OVER THE
NORTH. LOWS 28-35 WITH SKIES BECOMING MOSTLY CLEAR. -GIH
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 320 AM SUNDAY...
TUESDAY-WEDNESDAY NIGHT: DRY CONDITIONS AND NEAR NORMAL TEMPS.
EXPECT SOME DEGREE OF WARMING ON TUE (HIGHS MID/UPPER 50S) VIA
SOUTHWEST LOW-LEVEL FLOW AND WARM ADVECTION ASSOC/W A TIGHTENING
MSLP/HEIGHT GRADIENT IN ADVANCE OF A POTENT SHORTWAVE AND ATTENDANT
CLIPPER LOW DIGGING INTO THE GREAT LAKES. THE AFOREMENTIONED
SHORTWAVE ENERGY WILL PROGRESS INTO THE NORTHERN MID-ATLANTIC AND
NEW ENGLAND TUE NIGHT BEFORE MOVING OFFSHORE EARLY WED. THE
GFS/ECMWF GUIDANCE ARE ROUGHLY IN GOOD AGREEMENT ON THE EVOLUTION OF
THE AFOREMENTIONED SHORTWAVE ENERGY/CLIPPER SYSTEM...INDICATING A
WEAK/DRY COLD FRONTAL PASSAGE TUE EVE/NIGHT FOLLOWED BY WEAK HIGH
PRESSURE BUILDING INTO THE REGION ON WED. EXPECT LOWS IN THE LOWER
TO MID 30S WED MORNING (COOLEST N/NW)...WITH HIGHS ON WED SEVERAL
DEGREES COOLER THAN TUE IN THE LOWER 50S FAR NORTH TO MID/UPPER 50S
FAR SOUTH. WITH CLEAR SKIES...LIGHT/CALM WINDS AND A DRY AIRMASS IN
PLACE...EXPECT GOOD RADIATIONAL COOLING WITH LOWS IN THE UPPER 20S
TO LOWER 30S WED NIGHT.
THURSDAY-FRIDAY...EXPECT A WARMING TREND WITH INCREASING CLOUD
COVER. SHORTWAVE ENERGY IS EXPECTED TO DIG SOUTHEAST THROUGH THE
NORTHERN ROCKIES INTO THE UPPER MIDWEST THU/THU NIGHT... WITH AN
ATTENDANT SFC LOW TRACKING NE FROM THE CENTRAL PLAINS TO THE GREAT
LAKES AND AN ASSOCIATED COLD FRONT PROGRESSING EAST ACROSS THE MS
RIVER VALLEY. HIGH PRESSURE WILL MOVE OFFSHORE THE CAROLINA COAST IN
ADVANCE OF THE AFOREMENTIONED FRONT ON THU...RESULTING IN THE ONSET
OF SOUTHERLY RETURN FLOW /WARM ADVECTION/. WARM ADVECTION AND LOW-
LEVEL MOISTURE TRANSPORT WILL STRENGTHEN ON FRIDAY AS THE
AFOREMENTIONED FRONT PROGRESSES INTO THE TN/OH VALLEY AND THE
MSLP/HEIGHT GRADIENT TIGHTENS OVER THE CAROLINAS. EXPECT HIGHS IN
THE UPPER 50S TO NEAR 60F (S) ON THU...AND IN THE MID/UPPER 60S TO
NEAR 70F ON FRIDAY DEPENDING ON CLOUD COVER...WARMEST S/SE. THOUGH
LOW-LEVEL WARM ADVECTION (ALONE OR) IN THE PRESENCE OF ANY SMALL
AMPLITUDE DISTURBANCES IN WSW FLOW ALOFT COULD CONCEIVABLY RESULT IN
A LOW CHANCE FOR SPRINKLES OR LIGHT RAIN THU NIGHT/FRI MORNING...
WILL KEEP THE FCST DRY AT THIS TIME.
FRIDAY NIGHT-SATURDAY: UNCERTAINTY IN THE FORECAST INCREASES
DRAMATICALLY THIS WEEKEND WITH REGARD TO THE EVOLUTION OF A COMPLEX
UPPER LEVEL PATTERN CHARACTERIZED BY SPLIT FLOW. REGARDLESS...THE
OVERALL PATTERN WOULD SUGGEST AN ABOVE AVERAGE CHANCE FOR RAIN
ASSOC/W AN INCREASINGLY WARM/MOIST AIRMASS AND THE FRONTAL ZONE
APPROACHING FROM THE WEST. WILL INDICATE MOSTLY CLOUDY/OVERCAST
SKIES AND A 30% CHANCE OF RAIN ON SAT/SUN. -VINCENT
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 620 AM SUNDAY...
SUB-VFR AVIATION CONDITIONS WILL HOLD UNTIL SHORTLY AFTER
SUNRISE... WHEN IMPROVEMENT TO VFR IS EXPECTED BETWEEN 13Z AND 16Z.
A COMPLEX OF SURFACE LOW PRESSURE CENTERS CROSSING THE AREA IS
BRINGING UNSETTLED WEATHER IN THE FORM OF IFR/LIFR CIGS AND MVFR TO
IFR VSBYS EARLY THIS MORNING. THESE CLOUDS WILL PERSIST FOR A FEW
MORE HOURS... ALONG WITH PATCHY LIGHT RAIN THAT WILL CROSS CENTRAL
NC. THIS RAIN IS ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE THAT
WILL SWEEP THROUGH THE AREA EARLY THIS MORNING. ONCE THIS
DISTURBANCE PASSES TO OUR EAST NEAR OR SOON AFTER SUNRISE...LOW
LEVEL WINDS WILL BECOME FROM THE WNW OR NW (FROM 270-320 DEGREES)
AND WILL INCREASE IN SPEED TO 8-12 KTS OCCASIONALLY GUSTING TO 18-22
KTS MID-LATE MORNING THROUGH AFTERNOON. THIS DOWNSLOPE DRYING FLOW
WILL SCOUR OUT THE LOW CLOUDS BETWEEN 13Z (WRN TAFS) AND 16Z (ERN
TAFS). THUS...CONFIDENCE IS HIGH IN VFR CONDITIONS AT ALL SITES BY
MID AFTERNOON. WINDS WILL DIMINISH TO 8 KTS OR LESS AROUND SUNSET.
CLEAR SKIES AND VFR VSBYS ARE EXPECTED TONIGHT AS HIGH PRESSURE
NOSES INTO THE AREA.
LOOKING BEYOND 12Z MONDAY MORNING...HIGH CONFIDENCE IN VFR
CONDITIONS MONDAY THROUGH THURSDAY...AS SURFACE HIGH PRESSURE
DOMINATES WITH DRY WEATHER. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...VINCENT
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
322 AM EST SUN DEC 15 2013
.SYNOPSIS...AN UPPER LEVEL DISTURBANCE WILL CROSS THE CAROLINAS
EARLY THIS MORNING. HIGH PRESSURE WILL THEN BUILD INTO THE REGION
FROM THE SOUTHWEST LATE TODAY THROUGH MID WEEK... PROVIDING FAIR AND
DRY WEATHER. THIS HIGH WILL SHIFT OFF THE COAST LATE WEDNESDAY...
BRINGING A WARMING TREND THROUGH LATE WEEK.
&&
NEAR TERM /TODAY THROUGH TONIGHT/...
AS OF 215 AM SUNDAY...
THROUGH TODAY: GREATLY IMPROVING WEATHER IS EXPECTED THIS MORNING.
THE LATEST SURFACE MAP SHOWS THE WEDGE FRONT HAVING MOVED JUST EAST
OF THE CWA... WHILE THE PRIMARY OCCLUDED FRONT HAS MOVED INTO THE NC
MOUNTAINS. WE REMAIN ON THE EAST SIDE OF THE APPROACHING BROAD
TROUGH... AND WHILE THE HEAVIEST RAIN HAS SHIFTED OFF THE COAST... A
POCKET OF MID LEVEL VORTICITY SHEARING OUT OF THE TROUGH BASE ACROSS
THE CENTRAL CAROLINAS IS RESPONSIBLE FOR A BATCH OF MOSTLY LIGHT
RAIN STREAMING OVER THE AREA. THE LATEST HRRR GUIDANCE DEPICTS THIS
PRECIP WELL AND SHOWS THIS LIGHT RAIN AREA PUSHING EASTWARD OUT OF
THE CWA BETWEEN 8 AM AND 10 AM AS THE MID LEVEL TROUGH AXIS CROSSES
THE AREA. THICK LOW CLOUDS WILL PERSIST UNTIL THEN... AS WE`RE
SEEING COOLING AT THE SURFACE BUT THE 925 MB/850 MB TROUGH AXES ARE
STILL TO OUR WEST... YIELDING A VERTICAL THERMAL DIFFERENTIAL AND
FOSTERING LOW LEVEL STABILIZATION (EXACERBATED BY A LOOSE MSLP
GRADIENT AND LIGHT SURFACE WINDS)... HINDERING MIXING. AFTER THE
OCCLUDED FRONT PASSES THROUGH BY MID TO LATE MORNING... THE ENSUING
DOWNSLOPE LOW LEVEL FLOW WILL HELP DRY OUT THE LOWER TROPOSPHERE...
WHILE INCREASING DEEP LAYER SUBSIDENCE IN THE WAKE OF THE DEPARTING
BROAD TROUGH AXIS HELPS DRY AND STABILIZE THE MID-UPPER LEVELS.
EXPECT PLENTY OF SUNSHINE BY THE AFTERNOON HOURS. THICKNESSES DO
FALL DURING THE DAY (MUCH OF WHICH IS A FUNCTION OF COOLING AT 925-
850 MB WITH GOOD DRYING BUT NOT A LOT OF COOLING BELOW 925 MB)...
BUT THE INCOMING AIR MASS IS MODIFIED AND SOURCED FROM OUR WSW...
AND LATE-DAY THICKNESSES ARE STILL JUST SLIGHTLY BELOW NORMAL. HIGHS
49-57... NEAR TO SLIGHTLY UNDER SEASONAL NORMALS. EXPECT BREEZY WNW
WINDS WITH OCCASIONAL GUSTS AS THE COOLER AND MORE DENSE AIR ARRIVES
WITH SHALLOW BUT PRONOUNCED MIXING.
FOR TONIGHT: AS THE MID LEVEL TROUGH AXIS MOVES TO OUR EAST... A
PORTION OF THE SURFACE HIGH NOSES IN FROM THE SW... ENSURING
CONTINUED DRY AND STABLE LOW LEVELS... WHILE SUBSIDENCE CONTINUES
ALOFT. THESE LIGHT SURFACE WINDS ALONG WITH MOSTLY CLEAR SKIES AND
COLD AIR ADVECTION WILL FACILITATE RADIATIONAL COOLING. LOWS 26-32.
-GIH
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 250 AM SUNDAY...
EXPECT DRY AND GENERALLY QUIET WEATHER... ALTHOUGH IT MAY NOT BE
QUITE AS SUN-FILLED AS ONCE THOUGHT ACROSS NRN NC. A WEAK MID LEVEL
WAVE NOW OVER ALBERTA/MT WILL DIVE SE THEN EAST ACROSS THE
MIDATLANTIC/NC MONDAY... WITH A 100+ KT UPPER JET STREAKING INTO THE
REGION. MODEL FORECAST SOUNDINGS SHOW A SOMEWHAT MOIST LAYER BETWEEN
800 MB AND 600 MB OVER THE NRN HALF OF THE CWA... AND GIVEN THAT THE
EXPECTED VERTICAL THERMAL AND MOISTURE STRUCTURE WILL BE SUPPORTIVE
OF OROGRAPHIC ENHANCEMENT OF MID-HIGH CLOUDS IN THIS AREA... WILL
HAVE A FORECAST OF SKIES BECOMING PARTLY CLOUDY ROUGHLY ALONG/NORTH
OF HIGHWAY 64 FOR THE AFTERNOON THROUGH MID EVENING... FOLLOWED BY
CLEARING OVERNIGHT AS THE VORTICITY MAX MOVES TO OUR EAST.
THICKNESSES WILL BE ABOUT 15-20 M BELOW NORMAL... SUGGESTING HIGHS
FROM 47 NORTH TO 53 SOUTH WHEN FACTORING IN THE CLOUDS OVER THE
NORTH. LOWS 28-35 WITH SKIES BECOMING MOSTLY CLEAR. -GIH
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 320 AM SUNDAY...
TUESDAY-WEDNESDAY NIGHT: DRY CONDITIONS AND NEAR NORMAL TEMPS.
EXPECT SOME DEGREE OF WARMING ON TUE (HIGHS MID/UPPER 50S) VIA
SOUTHWEST LOW-LEVEL FLOW AND WARM ADVECTION ASSOC/W A TIGHTENING
MSLP/HEIGHT GRADIENT IN ADVANCE OF A POTENT SHORTWAVE AND ATTENDANT
CLIPPER LOW DIGGING INTO THE GREAT LAKES. THE AFOREMENTIONED
SHORTWAVE ENERGY WILL PROGRESS INTO THE NORTHERN MID-ATLANTIC AND
NEW ENGLAND TUE NIGHT BEFORE MOVING OFFSHORE EARLY WED. THE
GFS/ECMWF GUIDANCE ARE ROUGHLY IN GOOD AGREEMENT ON THE EVOLUTION OF
THE AFOREMENTIONED SHORTWAVE ENERGY/CLIPPER SYSTEM...INDICATING A
WEAK/DRY COLD FRONTAL PASSAGE TUE EVE/NIGHT FOLLOWED BY WEAK HIGH
PRESSURE BUILDING INTO THE REGION ON WED. EXPECT LOWS IN THE LOWER
TO MID 30S WED MORNING (COOLEST N/NW)...WITH HIGHS ON WED SEVERAL
DEGREES COOLER THAN TUE IN THE LOWER 50S FAR NORTH TO MID/UPPER 50S
FAR SOUTH. WITH CLEAR SKIES...LIGHT/CALM WINDS AND A DRY AIRMASS IN
PLACE...EXPECT GOOD RADIATIONAL COOLING WITH LOWS IN THE UPPER 20S
TO LOWER 30S WED NIGHT.
THURSDAY-FRIDAY...EXPECT A WARMING TREND WITH INCREASING CLOUD
COVER. SHORTWAVE ENERGY IS EXPECTED TO DIG SOUTHEAST THROUGH THE
NORTHERN ROCKIES INTO THE UPPER MIDWEST THU/THU NIGHT... WITH AN
ATTENDANT SFC LOW TRACKING NE FROM THE CENTRAL PLAINS TO THE GREAT
LAKES AND AN ASSOCIATED COLD FRONT PROGRESSING EAST ACROSS THE MS
RIVER VALLEY. HIGH PRESSURE WILL MOVE OFFSHORE THE CAROLINA COAST IN
ADVANCE OF THE AFOREMENTIONED FRONT ON THU...RESULTING IN THE ONSET
OF SOUTHERLY RETURN FLOW /WARM ADVECTION/. WARM ADVECTION AND LOW-
LEVEL MOISTURE TRANSPORT WILL STRENGTHEN ON FRIDAY AS THE
AFOREMENTIONED FRONT PROGRESSES INTO THE TN/OH VALLEY AND THE
MSLP/HEIGHT GRADIENT TIGHTENS OVER THE CAROLINAS. EXPECT HIGHS IN
THE UPPER 50S TO NEAR 60F (S) ON THU...AND IN THE MID/UPPER 60S TO
NEAR 70F ON FRIDAY DEPENDING ON CLOUD COVER...WARMEST S/SE. THOUGH
LOW-LEVEL WARM ADVECTION (ALONE OR) IN THE PRESENCE OF ANY SMALL
AMPLITUDE DISTURBANCES IN WSW FLOW ALOFT COULD CONCEIVABLY RESULT IN
A LOW CHANCE FOR SPRINKLES OR LIGHT RAIN THU NIGHT/FRI MORNING...
WILL KEEP THE FCST DRY AT THIS TIME.
FRIDAY NIGHT-SATURDAY: UNCERTAINTY IN THE FORECAST INCREASES
DRAMATICALLY THIS WEEKEND WITH REGARD TO THE EVOLUTION OF A COMPLEX
UPPER LEVEL PATTERN CHARACTERIZED BY SPLIT FLOW. REGARDLESS...THE
OVERALL PATTERN WOULD SUGGEST AN ABOVE AVERAGE CHANCE FOR RAIN
ASSOC/W AN INCREASINGLY WARM/MOIST AIRMASS AND THE FRONTAL ZONE
APPROACHING FROM THE WEST. WILL INDICATE MOSTLY CLOUDY/OVERCAST
SKIES AND A 30% CHANCE OF RAIN ON SAT/SUN. -VINCENT
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 125 AM SUNDAY...
SUB-VFR AVIATION CONDITIONS WILL HOLD UNTIL NEAR OR SHORTLY AFTER
SUNRISE... WHEN IMPROVEMENT TO VFR IS EXPECTED BETWEEN 12Z AND 16Z.
A COMPLEX OF SURFACE LOW PRESSURE CENTERS CROSSING THE AREA IS
BRINGING UNSETTLED WEATHER IN THE FORM OF IFR/LIFR CIGS AND MVFR TO
IFR VSBYS EARLY THIS MORNING. THESE CLOUDS WILL PERSIST FOR SEVERAL
MORE HOURS...ALONG WITH PATCHY LIGHT RAIN THAT WILL CROSS CENTRAL
NC. THIS RAIN IS ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE THAT
WILL SWEEP THROUGH THE AREA EARLY THIS MORNING. ONCE THIS
DISTURBANCE PASSES TO OUR EAST NEAR OR SOON AFTER SUNRISE...LOW
LEVEL WINDS WILL BECOME FROM THE WNW OR NW (FROM 270-320 DEGREES)
AND WILL INCREASE IN SPEED TO 8-12 KTS OCCASIONALLY GUSTING TO 18-22
KTS MID-LATE MORNING THROUGH AFTERNOON. THIS DOWNSLOPE DRYING FLOW
WILL SCOUR OUT THE LOW CLOUDS BETWEEN 12Z (WRN TAFS) AND 16Z (ERN
TAFS). THUS...CONFIDENCE IS HIGH IN VFR CONDITIONS AT ALL SITES BY
MID TO LATE AFTERNOON. WINDS WILL DIMINISH TO 8 KTS OR LESS AROUND
SUNSET. CLEAR SKIES AND VFR VSBYS ARE EXPECTED TONIGHT AS HIGH
PRESSURE NOSES INTO THE AREA.
LOOKING BEYOND 06Z TONIGHT...HIGH CONFIDENCE IN VFR CONDITIONS LATE
TONIGHT THROUGH THURSDAY...AS SURFACE HIGH PRESSURE DOMINATES WITH
DRY WEATHER. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...VINCENT
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
250 AM EST SUN DEC 14 2013
.SYNOPSIS...AN UPPER LEVEL DISTURBANCE WILL CROSS THE CAROLINAS
EARLY THIS MORNING. HIGH PRESSURE WILL THEN BUILD INTO THE REGION
FROM THE SOUTHWEST LATE TODAY THROUGH MID WEEK... PROVIDING FAIR AND
DRY WEATHER. THIS HIGH WILL SHIFT OFF THE COAST LATE WEDNESDAY...
BRINGING A WARMING TREND THROUGH LATE WEEK.
&&
NEAR TERM /TODAY THROUGH TONIGHT/...
AS OF 215 AM SUNDAY...
THROUGH TODAY: GREATLY IMPROVING WEATHER IS EXPECTED THIS MORNING.
THE LATEST SURFACE MAP SHOWS THE WEDGE FRONT HAVING MOVED JUST EAST
OF THE CWA... WHILE THE PRIMARY OCCLUDED FRONT HAS MOVED INTO THE NC
MOUNTAINS. WE REMAIN ON THE EAST SIDE OF THE APPROACHING BROAD
TROUGH... AND WHILE THE HEAVIEST RAIN HAS SHIFTED OFF THE COAST... A
POCKET OF MID LEVEL VORTICITY SHEARING OUT OF THE TROUGH BASE ACROSS
THE CENTRAL CAROLINAS IS RESPONSIBLE FOR A BATCH OF MOSTLY LIGHT
RAIN STREAMING OVER THE AREA. THE LATEST HRRR GUIDANCE DEPICTS THIS
PRECIP WELL AND SHOWS THIS LIGHT RAIN AREA PUSHING EASTWARD OUT OF
THE CWA BETWEEN 8 AM AND 10 AM AS THE MID LEVEL TROUGH AXIS CROSSES
THE AREA. THICK LOW CLOUDS WILL PERSIST UNTIL THEN... AS WE`RE
SEEING COOLING AT THE SURFACE BUT THE 925 MB/850 MB TROUGH AXES ARE
STILL TO OUR WEST... YIELDING A VERTICAL THERMAL DIFFERENTIAL AND
FOSTERING LOW LEVEL STABILIZATION (EXACERBATED BY A LOOSE MSLP
GRADIENT AND LIGHT SURFACE WINDS)... HINDERING MIXING. AFTER THE
OCCLUDED FRONT PASSES THROUGH BY MID TO LATE MORNING... THE ENSUING
DOWNSLOPE LOW LEVEL FLOW WILL HELP DRY OUT THE LOWER TROPOSPHERE...
WHILE INCREASING DEEP LAYER SUBSIDENCE IN THE WAKE OF THE DEPARTING
BROAD TROUGH AXIS HELPS DRY AND STABILIZE THE MID-UPPER LEVELS.
EXPECT PLENTY OF SUNSHINE BY THE AFTERNOON HOURS. THICKNESSES DO
FALL DURING THE DAY (MUCH OF WHICH IS A FUNCTION OF COOLING AT 925-
850 MB WITH GOOD DRYING BUT NOT A LOT OF COOLING BELOW 925 MB)...
BUT THE INCOMING AIR MASS IS MODIFIED AND SOURCED FROM OUR WSW...
AND LATE-DAY THICKNESSES ARE STILL JUST SLIGHTLY BELOW NORMAL. HIGHS
49-57... NEAR TO SLIGHTLY UNDER SEASONAL NORMALS. EXPECT BREEZY WNW
WINDS WITH OCCASIONAL GUSTS AS THE COOLER AND MORE DENSE AIR ARRIVES
WITH SHALLOW BUT PRONOUNCED MIXING.
FOR TONIGHT: AS THE MID LEVEL TROUGH AXIS MOVES TO OUR EAST... A
PORTION OF THE SURFACE HIGH NOSES IN FROM THE SW... ENSURING
CONTINUED DRY AND STABLE LOW LEVELS... WHILE SUBSIDENCE CONTINUES
ALOFT. THESE LIGHT SURFACE WINDS ALONG WITH MOSTLY CLEAR SKIES AND
COLD AIR ADVECTION WILL FACILITATE RADIATIONAL COOLING. LOWS 26-32.
-GIH
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 250 AM SUNDAY...
EXPECT DRY AND GENERALLY QUIET WEATHER... ALTHOUGH IT MAY NOT BE
QUITE AS SUN-FILLED AS ONCE THOUGHT ACROSS NRN NC. A WEAK MID LEVEL
WAVE NOW OVER ALBERTA/MT WILL DIVE SE THEN EAST ACROSS THE
MIDATLANTIC/NC MONDAY... WITH A 100+ KT UPPER JET STREAKING INTO THE
REGION. MODEL FORECAST SOUNDINGS SHOW A SOMEWHAT MOIST LAYER BETWEEN
800 MB AND 600 MB OVER THE NRN HALF OF THE CWA... AND GIVEN THAT THE
EXPECTED VERTICAL THERMAL AND MOISTURE STRUCTURE WILL BE SUPPORTIVE
OF OROGRAPHIC ENHANCEMENT OF MID-HIGH CLOUDS IN THIS AREA... WILL
HAVE A FORECAST OF SKIES BECOMING PARTLY CLOUDY ROUGHLY ALONG/NORTH
OF HIGHWAY 64 FOR THE AFTERNOON THROUGH MID EVENING... FOLLOWED BY
CLEARING OVERNIGHT AS THE VORTICITY MAX MOVES TO OUR EAST.
THICKNESSES WILL BE ABOUT 15-20 M BELOW NORMAL... SUGGESTING HIGHS
FROM 47 NORTH TO 53 SOUTH WHEN FACTORING IN THE CLOUDS OVER THE
NORTH. LOWS 28-35 WITH SKIES BECOMING MOSTLY CLEAR. -GIH
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 235 PM SATURDAY...
A LOW PRESSURE SYSTEM DIVING OUT OF THE CANADIAN ROCKIES WILL
APPROACH THE GREAT LAKES AND DIVE THROUGH NEW ENGLAND AS AN UPPER
LEVEL TROUGH DIGS DOWN THE EASTERN SEABOARD BUT WILL HAVE A HARD
TIME EXTENDING SOUTHWARD. THIS WILL MAKE UPPER LEVEL FLOW MORE ZONAL
OVER NORTH CAROLINA CAUSING A FAIRLY CONSTANT TEMPERATURE PATTERN
WITH SOME OSCILLATION IN HIGH AND LOW TEMPS FOR THE FIRST TWO THIRDS
OF THE PERIOD. BY THE END OF THE WEEK A FEW SHORTWAVES DEVELOP IN
THE SOUTHERN STREAM AND STRONG WARM AIR ADVECTION TAKES TEMPERATURES
WELL ABOVE SEASONAL NORMALS FOR FRIDAY AND SATURDAY BEFORE A
STRONGER LOW DEVELOPS AND MOVES THROUGH THE OHIO VALLEY ON SUNDAY.
TUESDAY: WHILE MODELS GENERALLY KEEP THE PATTERN THE SAME
...THE GFS HAS A BROADER SURFACE HIGH OVER THE REGION...THUS
SHUTTING OFF ANY SLIGHT COLD AIR ADVECTION ON THE FRONT SIDE OF THE
HIGH. THE ECMWF HANGS BACK WITH THIS AND THUS ITS TEMPERATURES ARE
COOLER. EITHER WAY A SLIGHT WARMING TREND FROM MONDAY TO TUESDAY
WITH UPPER 40S TO LOW 50S EXPECTED MONDAY AND MID 50S ON TUESDAY.
DRY AND MOSTLY CLEAR WITH VERY LIGHT WINDS OUT OF THE NORTHWEST.
LOWS IN THE LOWER TO MID 30S.
WEDNESDAY AND THURSDAY: A MORE NORTHWESTERLY UPPER LEVEL FLOW AND A
TIGHTER GRADIENT IN THE GFS YIELD SOME LOWER TEMPERATURES FOR
WEDNESDAY BUT THE PATTERN IS MORE RELAXED IN THE LATEST EUROPEAN
WITH MOST OF THE STRONGER DYNAMICS WELL TO THE NORTH. WILL INDICATE
A SMALL REDUCTION IN HIGHS ON WEDNESDAY...LOWER TO MID 50S WITH LOWS
IN THE LOWER 30S THURSDAY MORNING. ON THURSDAY UPPER LEVEL FLOW WILL
BEGIN TO BACK AROUND TO WESTERLY AND THEN SOUTHWESTERLY. AT THE SAME
TIME THE SURFACE HIGH MOVES OFF SHORT. THIS WILL BEGIN A PERIOD OF
SIGNIFICANT WARM AIR ADVECTION WHICH WILL PUT HIGHS ON THURSDAY INTO
THE MID TO UPPER 50S WITH LOWS IN THE LOWER 40S.
FRIDAY AND SATURDAY: AS FLOW BECOMES MORE SOUTHWESTERLY...INCREASED
WARM AIR ADVECTION WILL HELP TEMPERATURES RISE ABOVE SEASONAL
NORMALS. INCREASED MOISTURE AHEAD OF A DEVELOPING FRONTAL ZONE IN
THE TN VALLEY WILL BEGIN TO BRING MORE CLOUDS INTO THE AREA AND A
SLIGHT CHANCE OF SOME DRIZZLE OR LIGHT RAIN FRIDAY AFTERNOON AND
EVENING...INCREASING TO CHANCE OF RAIN BY SATURDAY. HIGHEST
POTENTIAL FOR RAIN WILL BE IN THE NORTHWEST. HIGHS POTENTIALLY
RISING TO THE MID TO UPPER 60S BY SATURDAY...ALMOST 15 DEGREES ABOVE
NORMAL FOR THIS TIME OF YEAR.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 125 AM SUNDAY...
SUB-VFR AVIATION CONDITIONS WILL HOLD UNTIL NEAR OR SHORTLY AFTER
SUNRISE... WHEN IMPROVEMENT TO VFR IS EXPECTED BETWEEN 12Z AND 16Z.
A COMPLEX OF SURFACE LOW PRESSURE CENTERS CROSSING THE AREA IS
BRINGING UNSETTLED WEATHER IN THE FORM OF IFR/LIFR CIGS AND MVFR TO
IFR VSBYS EARLY THIS MORNING. THESE CLOUDS WILL PERSIST FOR SEVERAL
MORE HOURS... ALONG WITH PATCHY LIGHT RAIN THAT WILL CROSS CENTRAL
NC. THIS RAIN IS ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE THAT
WILL SWEEP THROUGH THE AREA EARLY THIS MORNING. ONCE THIS
DISTURBANCE PASSES TO OUR EAST NEAR OR SOON AFTER SUNRISE... LOW
LEVEL WINDS WILL BECOME FROM THE WNW OR NW (FROM 270-320 DEGREES)
AND WILL INCREASE IN SPEED TO 8-12 KTS OCCASIONALLY GUSTING TO 18-22
KTS MID-LATE MORNING THROUGH AFTERNOON. THIS DOWNSLOPE DRYING FLOW
WILL SCOUR OUT THE LOW CLOUDS BETWEEN 12Z (WRN TAFS) AND 16Z (ERN
TAFS). THUS... CONFIDENCE IS HIGH IN VFR CONDITIONS AT ALL SITES BY
MID TO LATE AFTERNOON. WINDS WILL DIMINISH TO 8 KTS OR LESS AROUND
SUNSET. CLEAR SKIES AND VFR VSBYS ARE EXPECTED TONIGHT AS HIGH
PRESSURE NOSES INTO THE AREA.
LOOKING BEYOND 06Z TONIGHT... HIGH CONFIDENCE IN VFR CONDITIONS LATE
TONIGHT THROUGH THURSDAY... AS SURFACE HIGH PRESSURE DOMINATES WITH
DRY WEATHER. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
220 AM EST SUN DEC 14 2013
.SYNOPSIS...AN UPPER LEVEL DISTURBANCE WILL CROSS THE CAROLINAS
EARLY THIS MORNING. HIGH PRESSURE WILL THEN BUILD INTO THE REGION
FROM THE SOUTHWEST LATE TODAY THROUGH MID WEEK... PROVIDING FAIR AND
DRY WEATHER. THIS HIGH WILL SHIFT OFF THE COAST LATE WEDNESDAY...
BRINGING A WARMING TREND THROUGH LATE WEEK.
&&
NEAR TERM /TODAY THROUGH TONIGHT/...
AS OF 215 AM SUNDAY...
THROUGH TODAY: GREATLY IMPROVING WEATHER IS EXPECTED THIS MORNING.
THE LATEST SURFACE MAP SHOWS THE WEDGE FRONT HAVING MOVED JUST EAST
OF THE CWA... WHILE THE PRIMARY OCCLUDED FRONT HAS MOVED INTO THE NC
MOUNTAINS. WE REMAIN ON THE EAST SIDE OF THE APPROACHING BROAD
TROUGH... AND WHILE THE HEAVIEST RAIN HAS SHIFTED OFF THE COAST... A
POCKET OF MID LEVEL VORTICITY SHEARING OUT OF THE TROUGH BASE ACROSS
THE CENTRAL CAROLINAS IS RESPONSIBLE FOR A BATCH OF MOSTLY LIGHT
RAIN STREAMING OVER THE AREA. THE LATEST HRRR GUIDANCE DEPICTS THIS
PRECIP WELL AND SHOWS THIS LIGHT RAIN AREA PUSHING EASTWARD OUT OF
THE CWA BETWEEN 8 AM AND 10 AM AS THE MID LEVEL TROUGH AXIS CROSSES
THE AREA. THICK LOW CLOUDS WILL PERSIST UNTIL THEN... AS WE`RE
SEEING COOLING AT THE SURFACE BUT THE 925 MB/850 MB TROUGH AXES ARE
STILL TO OUR WEST... YIELDING A VERTICAL THERMAL DIFFERENTIAL AND
FOSTERING LOW LEVEL STABILIZATION (EXACERBATED BY A LOOSE MSLP
GRADIENT AND LIGHT SURFACE WINDS)... HINDERING MIXING. AFTER THE
OCCLUDED FRONT PASSES THROUGH BY MID TO LATE MORNING... THE ENSUING
DOWNSLOPE LOW LEVEL FLOW WILL HELP DRY OUT THE LOWER TROPOSPHERE...
WHILE INCREASING DEEP LAYER SUBSIDENCE IN THE WAKE OF THE DEPARTING
BROAD TROUGH AXIS HELPS DRY AND STABILIZE THE MID-UPPER LEVELS.
EXPECT PLENTY OF SUNSHINE BY THE AFTERNOON HOURS. THICKNESSES DO
FALL DURING THE DAY (MUCH OF WHICH IS A FUNCTION OF COOLING AT 925-
850 MB WITH GOOD DRYING BUT NOT A LOT OF COOLING BELOW 925 MB)...
BUT THE INCOMING AIR MASS IS MODIFIED AND SOURCED FROM OUR WSW...
AND LATE-DAY THICKNESSES ARE STILL JUST SLIGHTLY BELOW NORMAL. HIGHS
49-57... NEAR TO SLIGHTLY UNDER SEASONAL NORMALS. EXPECT BREEZY WNW
WINDS WITH OCCASIONAL GUSTS AS THE COOLER AND MORE DENSE AIR ARRIVES
WITH SHALLOW BUT PRONOUNCED MIXING.
FOR TONIGHT: AS THE MID LEVEL TROUGH AXIS MOVES TO OUR EAST... A
PORTION OF THE SURFACE HIGH NOSES IN FROM THE SW... ENSURING
CONTINUED DRY AND STABLE LOW LEVELS... WHILE SUBSIDENCE CONTINUES
ALOFT. THESE LIGHT SURFACE WINDS ALONG WITH MOSTLY CLEAR SKIES AND
COLD AIR ADVECTION WILL FACILITATE RADIATIONAL COOLING. LOWS 26-32.
-GIH
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 255 PM SATURDAY...
TO BE UPDATED.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 235 PM SATURDAY...
A LOW PRESSURE SYSTEM DIVING OUT OF THE CANADIAN ROCKIES WILL
APPROACH THE GREAT LAKES AND DIVE THROUGH NEW ENGLAND AS AN UPPER
LEVEL TROUGH DIGS DOWN THE EASTERN SEABOARD BUT WILL HAVE A HARD
TIME EXTENDING SOUTHWARD. THIS WILL MAKE UPPER LEVEL FLOW MORE ZONAL
OVER NORTH CAROLINA CAUSING A FAIRLY CONSTANT TEMPERATURE PATTERN
WITH SOME OSCILLATION IN HIGH AND LOW TEMPS FOR THE FIRST TWO THIRDS
OF THE PERIOD. BY THE END OF THE WEEK A FEW SHORTWAVES DEVELOP IN
THE SOUTHERN STREAM AND STRONG WARM AIR ADVECTION TAKES TEMPERATURES
WELL ABOVE SEASONAL NORMALS FOR FRIDAY AND SATURDAY BEFORE A
STRONGER LOW DEVELOPS AND MOVES THROUGH THE OHIO VALLEY ON SUNDAY.
TUESDAY: WHILE MODELS GENERALLY KEEP THE PATTERN THE SAME
...THE GFS HAS A BROADER SURFACE HIGH OVER THE REGION...THUS
SHUTTING OFF ANY SLIGHT COLD AIR ADVECTION ON THE FRONT SIDE OF THE
HIGH. THE ECMWF HANGS BACK WITH THIS AND THUS ITS TEMPERATURES ARE
COOLER. EITHER WAY A SLIGHT WARMING TREND FROM MONDAY TO TUESDAY
WITH UPPER 40S TO LOW 50S EXPECTED MONDAY AND MID 50S ON TUESDAY.
DRY AND MOSTLY CLEAR WITH VERY LIGHT WINDS OUT OF THE NORTHWEST.
LOWS IN THE LOWER TO MID 30S.
WEDNESDAY AND THURSDAY: A MORE NORTHWESTERLY UPPER LEVEL FLOW AND A
TIGHTER GRADIENT IN THE GFS YIELD SOME LOWER TEMPERATURES FOR
WEDNESDAY BUT THE PATTERN IS MORE RELAXED IN THE LATEST EUROPEAN
WITH MOST OF THE STRONGER DYNAMICS WELL TO THE NORTH. WILL INDICATE
A SMALL REDUCTION IN HIGHS ON WEDNESDAY...LOWER TO MID 50S WITH LOWS
IN THE LOWER 30S THURSDAY MORNING. ON THURSDAY UPPER LEVEL FLOW WILL
BEGIN TO BACK AROUND TO WESTERLY AND THEN SOUTHWESTERLY. AT THE SAME
TIME THE SURFACE HIGH MOVES OFF SHORT. THIS WILL BEGIN A PERIOD OF
SIGNIFICANT WARM AIR ADVECTION WHICH WILL PUT HIGHS ON THURSDAY INTO
THE MID TO UPPER 50S WITH LOWS IN THE LOWER 40S.
FRIDAY AND SATURDAY: AS FLOW BECOMES MORE SOUTHWESTERLY...INCREASED
WARM AIR ADVECTION WILL HELP TEMPERATURES RISE ABOVE SEASONAL
NORMALS. INCREASED MOISTURE AHEAD OF A DEVELOPING FRONTAL ZONE IN
THE TN VALLEY WILL BEGIN TO BRING MORE CLOUDS INTO THE AREA AND A
SLIGHT CHANCE OF SOME DRIZZLE OR LIGHT RAIN FRIDAY AFTERNOON AND
EVENING...INCREASING TO CHANCE OF RAIN BY SATURDAY. HIGHEST
POTENTIAL FOR RAIN WILL BE IN THE NORTHWEST. HIGHS POTENTIALLY
RISING TO THE MID TO UPPER 60S BY SATURDAY...ALMOST 15 DEGREES ABOVE
NORMAL FOR THIS TIME OF YEAR.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 125 AM SUNDAY...
SUB-VFR AVIATION CONDITIONS WILL HOLD UNTIL NEAR OR SHORTLY AFTER
SUNRISE... WHEN IMPROVEMENT TO VFR IS EXPECTED BETWEEN 12Z AND 16Z.
A COMPLEX OF SURFACE LOW PRESSURE CENTERS CROSSING THE AREA IS
BRINGING UNSETTLED WEATHER IN THE FORM OF IFR/LIFR CIGS AND MVFR TO
IFR VSBYS EARLY THIS MORNING. THESE CLOUDS WILL PERSIST FOR SEVERAL
MORE HOURS... ALONG WITH PATCHY LIGHT RAIN THAT WILL CROSS CENTRAL
NC. THIS RAIN IS ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE THAT
WILL SWEEP THROUGH THE AREA EARLY THIS MORNING. ONCE THIS
DISTURBANCE PASSES TO OUR EAST NEAR OR SOON AFTER SUNRISE... LOW
LEVEL WINDS WILL BECOME FROM THE WNW OR NW (FROM 270-320 DEGREES)
AND WILL INCREASE IN SPEED TO 8-12 KTS OCCASIONALLY GUSTING TO 18-22
KTS MID-LATE MORNING THROUGH AFTERNOON. THIS DOWNSLOPE DRYING FLOW
WILL SCOUR OUT THE LOW CLOUDS BETWEEN 12Z (WRN TAFS) AND 16Z (ERN
TAFS). THUS... CONFIDENCE IS HIGH IN VFR CONDITIONS AT ALL SITES BY
MID TO LATE AFTERNOON. WINDS WILL DIMINISH TO 8 KTS OR LESS AROUND
SUNSET. CLEAR SKIES AND VFR VSBYS ARE EXPECTED TONIGHT AS HIGH
PRESSURE NOSES INTO THE AREA.
LOOKING BEYOND 06Z TONIGHT... HIGH CONFIDENCE IN VFR CONDITIONS LATE
TONIGHT THROUGH THURSDAY... AS SURFACE HIGH PRESSURE DOMINATES WITH
DRY WEATHER. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...NP
LONG TERM...ELLIS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1227 AM EST SUN DEC 15 2013
.SYNOPSIS...
LOW PRESSURE WILL PASS WEST OF THE AREA TONIGHT...BRINGING PERIODS OF
RAIN INTO SUNDAY. A COLD FRONT WILL CROSS THE COAST EARLY ON
SUNDAY...BRINGING COOL AND DRY WEATHER INTO EARLY NEXT WEEK. DRY
AND SEASONABLE WEATHER EXPECTED MUCH OF NEXT WEEK AS SURFACE HIGH
PRESSURE IS REINFORCED OVER THE AREA. A LOW PRESSURE SYSTEM WILL
APPROACH THE AREA NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1200 AM SUNDAY...TORNADO WATCH HAS BEEN CANCELLED FOR THE
REMAINING ILM NC CWA. WINDS THRU THE ATM COLUMN HAVE BECOME MORE
UNIDIRECTIONAL...DIMINISHING THE TORNADO THREAT SOMEWHAT...
EVENTHOUGH SOME SPEED SHEAR REMAINS. INSTABILITY IS NO LONGER
EVIDENT AND PLENTIFUL LIKE EARLIER THIS EVENING RELATIVELY
SPEAKING.
A NE TO SW SFC BOUNDARY EXTENDS ACROSS THE FA...IE. COULD CALL IT
A PRE-FRONTAL BOUNDARY...HAS PUSHED EASTWARD ACROSS THE ILM CWA
RESULTING WITH SFC WINDS VEERING TO THE SW-W. THE SFC COLD FRONT
IS LAGGING BEHIND BUT SHOULD PUSH THROUGH EITHER OVERNIGHT OR
DURING SUNDAY. AFTER THE CFP...LOOK FOR A TREND OF DECREASING
TEMPS/DEWPTS AND WINDS VEERING TO THE NW-N. COULD OBSERVE POST
FRONTAL LIGHT PCPN. THE MAJORITY OF THE PCPN ACTIVITY HAS PUSHED
AWAY FROM THE ILM NC CWA AND ADJACENT WATERS. AND NO LONGER POSES
A SVR THREAT FOR THE ILM CWA.
THE SFC BASED MARINE LAYER HAD PUSHED PARTIALLY INLAND FROM THE
SE-S WINDS EARLIER TODAY BUT IS APPARENTLY NOT DEEP ENOUGH TO
PREVENT THUNDERSTORM DEVELOPMENT. LOCAL SHELF WATER SSTS ARE IN
THE 50S...BUT SSTS IN THE 70S LURK JUST BEYOND 20 NM OUT FROM THE
COAST. ONCE THE 50S SSTS EXPAND FURTHER FROM THE CAROLINA COASTS
DURING THIS WINTER SEASON...THE MARINE LAYER WILL BECOME MORE
PREVALENT AND A DETERRENT FOR CONVECTIVE DEVELOPMENT. MINOR TWEAKS
FOR PCPN TIMING AS IT TRACKS ACROSS THE FA HAVE BEEN APPLIED. THE
WEAK INSTABILITY FOR CONVECTION HAS BEEN OVERCOME BY THE POTENT
DYNAMICS FROM A ROBUST MID-LEVEL S/W TROF PUSHING ACROSS THE SE
STATES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
AS OF 230 PM SATURDAY...THE SHORT TERM FORECAST IS RATHER STRAIGHT
FORWARD AS THE MID LEVEL TROUGH WILL CONTINUE TO MOVE OFFSHORE
SUNDAY WITH A MODEST NORTHWEST FLOW ENSUING THROUGH THE REMAINDER
OF THE PERIOD.
AT THE SURFACE...HIGH PRESSURE BUILDS IN FROM THE NORTHWEST THEN THE
SURFACE PATTERN SHOWS A WEAKNESS DEVELOPING LATER MONDAY. ALTHOUGH
THERE ARE WEAK SHORTWAVES IN THE FLOW...NONE ARE STRONG ENOUGH TO
REINFORCE THE MODEST COLD AIR ADVECTION THAT MOVES IN SUNDAY.
OVERALL GUIDANCE REMAINS IN GOOD AGREEMENT WITH HIGHS IN THE 50S AND
LOWS IN THE 30S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...ZONAL FLOW ON TUESDAY EVEN AS IMPRESSIVE JET
OF 100KT DIVES ACROSS NRN PLAINS. THE MID LEVEL WAVE WRAPS UP FAIRLY
QUICKLY AND THUS DOES NOT LEAD TO A VERY DEEP TROUGH. EVEN SO IT
WILL MANAGE TO PUSH A RAIN-FREE COLD FRONT THROUGH THE CAROLINAS
TUESDAY NIGHT. HIGH RISES ALREADY UNDERWAY THOUGH WEDNESDAY MORNING
AS THE SYSTEM ALOFT SWINGS NEGATIVE AND LIFTS INTO NEW ENGLAND.
WEDNESDAY IS WHEN SURFACE PRESSURE GRADIENT FINALLY BECOMES LESS
NOISY AS HIGH PRESSURE CONGEALS OVER THE NC SOUNDS WHILE SUBTLE MID
LEVEL HEIGHT RISES CONTINUE. SURFACE RIDGE MOVES CONSIDERABLY TO THE
EAST FOR THE LATE WEEK PERIOD AND MID LEVEL TROUGHINESS DEVELOPS
OVER THE SWRN U.S. BOUNDARY LAYER WARMTH AND MOISTURE WILL BE ON THE
RISE BUT NOT SUFFICIENTLY FOR ANY MEANINGFUL RAIN CHANCES.
&&
.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...CONVECTION ONGOING WITH BRIEF PERIODS OF 1-2SM
VISIBILITY IN HEAVY SHOWERS...WITH ISOLATED EMBEDDED THUNDER. STRONG
HELICITY COUNTERED BY WEAK CAPE WILL LIKELY PRODUCE ISOLATED SEVERE
WEATHER. MOST OF THE ACTIVITY WILL BE OVER BY 03Z. THE HRRR HAS A
SECONDARY LINE MOVING FROM WEST TO EAST ALONG THE FRONT...BUT THE
AREA IS WEAKER THAN THE EARLIER MAIN LINE. LOOK FOR BRIEF BOUTS OF
IFR STRATUS. OVERNIGHT...CONDITIONS WILL IMPROVE AS THE THE FRONT
MOVES THROUGH. WINDS WILL SHIFT TO THE WEST...REMAINING ELEVATED.
SHOWERS WILL END FROM WEST TO EAST BY 06-08Z. BECOMING VFR TOWARD
MORNING...CONTINUING ON SUNDAY WITH A GUSTY NORTHWEST WIND.
EXTENDED OUTLOOK...SHOWERS LIKELY WITH PERIODS OF MVFR/IFR
CONDITIONS INTO EARLY SUNDAY. VFR DEVELOPING SUNDAY AND
PERSISTING THROUGH MID-WEEK.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1210 AM SUNDAY...REMAINING TORNADO-WATERSPOUT WATCH HAS BEEN
CANCELLED. THE MARINE LAYER ACROSS THE ILM COASTAL WATERS WHERE
SSTS IN THE 50S...REMAINS JUST THICK ENOUGH TO PREVENT THE HIER
SUSTAINED WINDS ALOFT FROM WORKING THEIR WAY TO THE OCEAN SFC.
THIS WILL RESULT IN THE CONTINUATION OF A STRONG SCA ACROSS ALL
WATERS...WITH A FEW GALE FORCE GUSTS POSSIBLE ACROSS THE OUTER
WATERS OFF CAPE FEAR. JUST BEYOND 20 NM OUT...SSTS ARE IN THE 60S
AND 70S ALLOWING THE STRONGER WINDS ALOFT TO MIX DOWN TO THE OCEAN
SFC. WITH A SW WIND...AN ONSHORE TO PARALLEL TRAJECTORY...THE HIER
WIND DRIVEN WAVES PRODUCED JUST OFFSHORE...IE. LATEST BUOY 41013
AT 15 FEET...WILL PUSH INTO THE COASTAL WATERS. AS A RESULT...
HAVE MODIFIED THE SIGNIFICANT SEAS ACROSS THE COASTAL WATERS BY
TWEAKING THEM TO MESH THE CURRENT CONDITIONS WITH THE FORECAST.
THE SFC BOUNDARY EXTENDING NE-SW HAS PARTIALLY PUSHED THROUGH THE
COASTAL WATERS...WITH WINDS VEERING TO THE SW-W. THE NEXT VEERING
OF THE WINDS TO NW-N WILL OCCUR WITH THE CFP EITHER DURING THE
PRE- DAWN SUNDAY HRS OR SOON THERE-AFTER.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 230 PM SATURDAY...INITIALLY A WESTERLY FLOW WILL BE IN PLACE
OVER THE WATERS IN A RANGE OF 15-20 KNOTS. AS SUNDAY
PROGRESSES...WINDS WILL OBTAIN A MORE NORTHWESTERLY COMPONENT AND
DECREASE. THE WINDS WILL VERY GRADUALLY DIMINISH TO 10-15 KNOTS
THROUGH THE REMAINDER OF THE PERIOD. AS FOR SEAS...THE CHANGE IN
FETCH WILL BE WELL UNDERWAY EARLY WITH A FEW SIX FOOTERS REMAINING
ACROSS THE OUTER WATERS WITH A WIDE RANGE OF 2-6 FEET. SEAS WILL
GRADUALLY DIMINISH TO 2-3 FEET BY MONDAY.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 230 PM SATURDAY...WEST TO SOUTHWEST WINDS PICK UP AHEAD OF A
COLD FRONT ON TUESDAY. THE OFFSHORE FLOW DIRECTION BUILDS SEAS AWAY
FROM SHORE TO 3 OR 4 FT WHILE LANDMASS WAVE SHADOWING KEEPS THE
NEARSHORE WAVES CLOSER TO 2 FT. VEERING FLOW BEHIND THE BOUNDARY ON
WEDNESDAY TO SHORTEN THE PERIOD SOMEWHAT AS WAVE FACES STEEPEN BUT
LITTLE OVERALL CHANGE IN SIG WAVE HEIGHT EXPECTED. THURSDAY PUTS US
INTO A SOUTHERLY RETURN FLOW REGIME THAT WILL LAST FOR SEVERAL
DAYS. ANY BUILDING OF SEAS WILL BE GRADUAL AND LIKELY NOT OCCUR
UNTIL AFTER THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR AMZ250-
252-254-256.
&&
$$
SYNOPSIS...SHK
NEAR TERM...DCH
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...TRA/DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1145 PM EST SAT DEC 14 2013
.SYNOPSIS...
LOW PRESSURE WILL PASS WEST OF THE AREA TONIGHT...BRINGING PERIODS OF
RAIN INTO SUNDAY. A COLD FRONT WILL CROSS THE COAST EARLY ON
SUNDAY...BRINGING COOL AND DRY WEATHER INTO EARLY NEXT WEEK. DRY
AND SEASONABLE WEATHER EXPECTED MUCH OF NEXT WEEK AS SURFACE HIGH
PRESSURE IS REINFORCED OVER THE AREA. A LOW PRESSURE SYSTEM WILL
APPROACH THE AREA NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 1100 PM SATURDAY...TORNADO WATCH IN EFFECT FOR PORTIONS OF
THE ILM CWA THRU 200 AM EST SUNDAY. BASICALLY IT INCLUDES ALL OF
THE ILM NC CWA...WITH THE ILM SC CWA HAVING BEEN CANCELED. WINDS
THRU THE ATM COLUMN ESPECIALLY ACROSS THE ILM SC CWA HAS BECOME
MORE UNIDIRECTIONAL...DIMINISHING THE TORNADO THREAT
SOMEWHAT...WITH DECENT SPEED SHEAR REMAINING
A NE TO SW SFC BOUNDARY EXTENDS ACROSS THE FA...IE. COULD CALL IT
A PRE-FRONTAL BOUNDARY...HAS PUSHED EASTWARD ACROSS THE MAJORITY
OF THE ILM CWA RESULTING WITH SFC WINDS VEERING TO THE SW-W. THE
SFC COLD FRONT LAGGING BEHIND BUT SHOULD PUSH THROUGH EITHER
OVERNIGHT OR DURING SUNDAY. AFTER THE CFP...LOOK FOR A TREND OF
DECREASING TEMPS/DEWPTS AND WINDS VEERING TO THE NW-N. COULD
OBSERVE POST FRONTAL LIGHT PCPN BUT THE MAJORITY OF THE STRONGER
PCPN ACTIVITY IS PASSING ACROSS THE ILM NC CWA AND ADJACENT
WATERS. AND EVEN THIS AREA OF ISOLATED CONVECTION HAS BECOME LESS
POTENT COMPARED TO EARLIER THIS EVENING.
THE SFC BASED MARINE LAYER HAD PUSHED PARTIALLY INLAND FROM THE
SE-S WINDS BUT IS APPARENTLY NOT DEEP ENOUGH TO PREVENT
THUNDERSTORM DEVELOPMENT. LOCAL SHELF WATERS SSTS ARE IN THE
50S...BUT SSTS IN THE 70S LURK JUST BEYOND 20 NM OUT FROM THE
COAST. ONCE THE 50S SSTS EXPAND FURTHER FROM THE CAROLINA COASTS
DURING THIS WINTER SEASON...THE MARINE LAYER WILL BECOME MORE
PREVALENT AND A DETERRENT FOR CONVECTIVE DEVELOPMENT. MINOR TWEAKS
FOR PCPN TIMING AS IT TRACKS ACROSS THE FA HAVE BEEN APPLIED. THE
WEAK INSTABILITY FOR CONVECTION HAS BEEN OVERCOME BY THE POTENT
DYNAMICS FROM A ROBUST MID-LEVEL S/W TROF PUSHING ACROSS THE SE
STATES.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 230 PM SATURDAY...THE SHORT TERM FORECAST IS RATHER STRAIGHT
FORWARD AS THE MID LEVEL TROUGH WILL CONTINUE TO MOVE OFFSHORE
SUNDAY WITH A MODEST NORTHWEST FLOW ENSUING THROUGH THE REMAINDER
OF THE PERIOD.
AT THE SURFACE...HIGH PRESSURE BUILDS IN FROM THE NORTHWEST THEN THE
SURFACE PATTERN SHOWS A WEAKNESS DEVELOPING LATER MONDAY. ALTHOUGH
THERE ARE WEAK SHORTWAVES IN THE FLOW...NONE ARE STRONG ENOUGH TO
REINFORCE THE MODEST COLD AIR ADVECTION THAT MOVES IN SUNDAY.
OVERALL GUIDANCE REMAINS IN GOOD AGREEMENT WITH HIGHS IN THE 50S AND
LOWS IN THE 30S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...ZONAL FLOW ON TUESDAY EVEN AS IMPRESSIVE JET
OF 100KT DIVES ACROSS NRN PLAINS. THE MID LEVEL WAVE WRAPS UP FAIRLY
QUICKLY AND THUS DOES NOT LEAD TO A VERY DEEP TROUGH. EVEN SO IT
WILL MANAGE TO PUSH A RAIN-FREE COLD FRONT THROUGH THE CAROLINAS
TUESDAY NIGHT. HIGH RISES ALREADY UNDERWAY THOUGH WEDNESDAY MORNING
AS THE SYSTEM ALOFT SWINGS NEGATIVE AND LIFTS INTO NEW ENGLAND.
WEDNESDAY IS WHEN SURFACE PRESSURE GRADIENT FINALLY BECOMES LESS
NOISY AS HIGH PRESSURE CONGEALS OVER THE NC SOUNDS WHILE SUBTLE MID
LEVEL HEIGHT RISES CONTINUE. SURFACE RIDGE MOVES CONSIDERABLY TO THE
EAST FOR THE LATE WEEK PERIOD AND MID LEVEL TROUGHINESS DEVELOPS
OVER THE SWRN U.S. BOUNDARY LAYER WARMTH AND MOISTURE WILL BE ON THE
RISE BUT NOT SUFFICIENTLY FOR ANY MEANINGFUL RAIN CHANCES.
&&
.AVIATION /04Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...CONVECTION ONGOING WITH BRIEF PERIODS OF 1-2SM
VISIBILITY IN HEAVY SHOWERS...WITH ISOLATED EMBEDDED THUNDER. STRONG
HELICITY COUNTERED BY WEAK CAPE WILL LIKELY PRODUCE ISOLATED SEVERE
WEATHER. MOST OF THE ACTIVITY WILL BE OVER BY 03Z. THE HRRR HAS A
SECONDARY LINE MOVING FROM WEST TO EAST ALONG THE FRONT...BUT THE
AREA IS WEAKER THAN THE EARLIER MAIN LINE. LOOK FOR BRIEF BOUTS OF
IFR STRATUS. OVERNIGHT...CONDITIONS WILL IMPROVE AS THE THE FRONT
MOVES THROUGH. WINDS WILL SHIFT TO THE WEST...REMAINING ELEVATED.
SHOWERS WILL END FROM WEST TO EAST BY 06-08Z. BECOMING VFR TOWARD
MORNING...CONTINUING ON SUNDAY WITH A GUSTY NORTHWEST WIND.
EXTENDED OUTLOOK...SHOWERS LIKELY WITH PERIODS OF MVFR/IFR
CONDITIONS INTO EARLY SUNDAY. VFR DEVELOPING SUNDAY AND
PERSISTING THROUGH MID-WEEK.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 PM SATURDAY...WATERSPOUT WATCH REMAINS IN EFFECT FOR
THE ILM NC COASTAL WATERS THROUGH 2 AM. THE MARINE LAYER ACROSS
THE ILM COASTAL WATERS WHERE SSTS ARE IN THE 50S...REMAINS JUST
THICK ENOUGH TO PREVENT THE HIER SUSTAINED WINDS ALOFT FROM
WORKING THEIR WAY TO THE OCEAN SFC. THIS WILL RESULT IN THE
CONTINUATION OF A STRONG SCA ACROSS ALL WATERS...WITH A FEW GALE
FORCE GUSTS POSSIBLE ACROSS THE OUTER WATERS OFF CAPE FEAR. JUST
BEYOND 20 NM OUT...SSTS ARE IN THE 60S AND 70S ALLOWING THE
STRONGER WINDS ALOFT TO MIX DOWN TO THE OCEAN SFC. WITH A S-SW
WIND...AN ONSHORE TO PARALLEL TRAJECTORY...THE HIER WIND DRIVEN
WAVES PRODUCED JUST OFFSHORE...IE. LATEST BUOY 41013 AT 15 FEET
...WILL PUSH INTO THE COASTAL WATERS. AS A RESULT...HAVE
MODIFIED THE SIGNIFICANT SEAS ACROSS THE COASTAL WATERS BY
TWEAKING THEM TO MESH WITH THE CURRENT CONDITIONS AND FORECAST.
THE SFC BOUNDARY EXTENDING NE-SW HAS PARTIALLY PUSHED INTO THE
COASTAL WATERS...WITH WINDS VEERING TO THE S-SW. THE NEXT VEERING
OF THE WINDS TO NW-N WILL OCCUR WITH THE CFP EITHER DURING THE
PRE-DAWN SUNDAY HRS OR SOON THERE-AFTER.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 230 PM SATURDAY...INITIALLY A WESTERLY FLOW WILL BE IN PLACE
OVER THE WATERS IN A RANGE OF 15-20 KNOTS. AS SUNDAY
PROGRESSES...WINDS WILL OBTAIN A MORE NORTHWESTERLY COMPONENT AND
DECREASE. THE WINDS WILL VERY GRADUALLY DIMINISH TO 10-15 KNOTS
THROUGH THE REMAINDER OF THE PERIOD. AS FOR SEAS...THE CHANGE IN
FETCH WILL BE WELL UNDERWAY EARLY WITH A FEW SIX FOOTERS REMAINING
ACROSS THE OUTER WATERS WITH A WIDE RANGE OF 2-6 FEET. SEAS WILL
GRADUALLY DIMINISH TO 2-3 FEET BY MONDAY.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 230 PM SATURDAY...WEST TO SOUTHWEST WINDS PICK UP AHEAD OF A
COLD FRONT ON TUESDAY. THE OFFSHORE FLOW DIRECTION BUILDS SEAS AWAY
FROM SHORE TO 3 OR 4 FT WHILE LANDMASS WAVE SHADOWING KEEPS THE
NEARSHORE WAVES CLOSER TO 2 FT. VEERING FLOW BEHIND THE BOUNDARY ON
WEDNESDAY TO SHORTEN THE PERIOD SOMEWHAT AS WAVE FACES STEEPEN BUT
LITTLE OVERALL CHANGE IN SIG WAVE HEIGHT EXPECTED. THURSDAY PUTS US
INTO A SOUTHERLY RETURN FLOW REGIME THAT WILL LAST FOR SEVERAL
DAYS. ANY BUILDING OF SEAS WILL BE GRADUAL AND LIKELY NOT OCCUR
UNTIL AFTER THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST SUNDAY FOR AMZ250-252-254-
256.
&&
$$
SYNOPSIS...SHK
NEAR TERM...DCH
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...DL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
932 PM CST MON DEC 16 2013
.UPDATE...
ISSUED AT 932 PM CST MON DEC 16 2013
MAIN UPDATE THIS EVENING WAS TO BUMP UP POPS THROUGH MIDNIGHT OVER
THE SOUTHWEST. BAND OF LIGHT SNOW INDUCED BY A SHORTWAVE IN
NORTHWEST UPPER FLOW HAD DEVELOPED FROM NEAR BEACH SOUTHWEST TO
AROUND HETTINGER. THIS BAND SHOULD MOVE QUICKLY SOUTHEAST BUT WILL
PRODUCE PERIODS OF LIGHT TO MODERATE SNOW. WINDS HAVE DIMINISHED
OVER THE SOUTHWEST SO NOT MUCH PROBLEM WITH BLOWING SNOW HERE.
THINK SNOW WILL BE PRETTY MUCH OUT OF THE AREA AROUND MIDNIGHT.
ELSEWHERE...STRONG WINDS CONTINUE OVER CENTRAL NORTH DAKOTA WITH
GUSTS TO 35 MPH AT MINOT AND BISMARCK EAST TO RUGBY...CARRINGTON
AND JAMESTOWN. EXPECT AREAS OF BLOWING AND DRIFTING SNOW TO
CONTINUE THROUGH LATE TONIGHT. ISOLATED SNOW SHOWERS FROM
CARRINGTON TO JAMESTOWN WILL MOVE QUICKLY SOUTHEAST...HOWEVER A
BRIEF FLURRY OR SNOW SHOWER CANNOT BE COMPLETELY RULED OUT MOST
ANYWHERE THROUGH LATE THIS EVENING.
UPDATE ISSUED AT 644 PM CST MON DEC 16 2013
LATEST RADAR LOOP IS STILL SHOWING SOME LIGHT REFLECTIVITIES
ACROSS WESTERN AND CENTRAL NORTH DAKOTA...BUT LITTLE IN THE WAY OF
SURFACE REPORTS VIA OBSERVATIONS OR WEATHER CAMERAS. STILL KEPT
SOME POPS IN THE SOUTHWEST...HIGHEST EARLY THIS EVENING AND
TAPERING THROUGH LATE EVENING. ALSO SOME SNOW SHOWERS OVER ROLETTE
COUNTY SO BUMPED UP POPS OVER NORTHEAST ROLETTE FOR A COUPLE
HOURS. RAISED SKY COVER OVER THE SOUTHWEST AND GENERALLY BUMPED UP
SKY ACROSS THE AREA THROUGH THE EVENING AS THERE ARE QUITE A BIT
OF MID AND HIGH LEVEL CLOUDS TRAVERSING THE AREA IN NORTHWEST
FLOW.
RECEIVED QUITE A FEW RESPONSES VIA SOCIAL MEDIA ABOUT THE
SLIPPERY ROADS ACROSS MAINLY THE NORTH. WILL EXTEND THE SPS FOR
ICY CONDITIONS THROUGH THE EVENING HOURS AS WE WILL REMAIN BREEZY
AND TEMPERATURES DROP BELOW FREEZING.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY AFTERNOON)
ISSUED AT 334 PM CST MON DEC 16 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE AREAS OF
BLOWING/DRIFTING SNOW RESULTING IN POSSIBLE ICY ROADS/BLACK ICE
ACROSS THE NORTH THROUGH THIS EVENING...AND A CHANCE OF LIGHT SNOW
THIS AFTERNOON AND EVENING WEST TO EAST.
CURRENTLY...STRONG NORTHWEST FLOW ALOFT WITH A SHARP RIDGE OFF
THE WEST COAST AND A BROAD LONG WAVE TROUGH OVER THE EASTERN
UNITED STATES. UPPER LEVEL JET STREAM EXTENDS FROM THE TOP OF THE
RIDGE OVER ALASKA...SOUTHEAST INTO THE NORTHERN HIGH PLAINS OF
MT/WY. STRONG PRESSURE GRADIENT CONTINUES TO DEVELOP ACROSS WEST
AND CENTRAL NORTH DAKOTA WEST OF A SURFACE TROUGH OVER FAR WESTERN
MINNESOTA. GRADIENT FORCING WILL INCREASE THROUGHOUT THE DAY AND
INTO THIS EVENING AS THE TROUGH REMAINS QUASI-STATIONARY AND AS A
SURFACE HIGH BUILDS OFF TO OUR WEST CENTERED OVER THE NORTHEASTERN
SNAKE RIVER VALLEY OF EASTERN IDAHO.
MODELS EARLIER WERE LOOKING LIKE THEY WERE TRENDING TOWARDS A
CONSENSUS REGARDING PRECIPITATION CHANCES THIS AFTERNOON AND
EVENING. NOW NOT SO MUCH. MOISTURE IS HAVING A HARD TIME REACHING
THE GROUND ACROSS MY WEST CENTRAL. WEB CAMS OVER SOUTHWEST NORTH
DAKOTA DEFINITELY SHOWING SNOWFALL ALTHOUGH MOSTLY MELTING ON THE
ROAD SURFACES. BOWMAN RADAR STILL LIT UP...AND BAKER MT STILL
REPORTING SNOW. THE 12Z ECMWF AND LATEST RAP SEEM TO BE CAPTURING
REALITY THE BEST VERSUS OTHER GUIDANCE. LEANED IN THEIR DIRECTION
WITH LINGERING LIGHT PRECIPITATION SOUTHWEST NOW THROUGH THIS
EVENING...AND ANOTHER AREA OF LIGHT PRECIPITATION MOVING SOUTHEAST
OVER MY EASTERN COUNTIES LATE AFTERNOON AND EVENING. THIS AREA
CURRENTLY SHOWING UP ON RADAR OVER SOUTHEAST SK/SOUTHWEST
MANITOBA.
THE INCREASING PRESSURE GRADIENT WILL SEE WINDS INCREASE TO JUST
BELOW WIND ADVISORY CRITERIA MOST LOCATIONS NOW THROUGH THE
EVENING HOURS...BEFORE WINDING DOWN AFTER 06Z. AT THIS TIME WINDS
ARE SUSTAINED AT 15-25 MPH MOST LOCATIONS...WITH GUSTS AS HIGH AS
35 MPH REPORTED. ROAD SFC TEMPS REMAIN AT OR BELOW FREEZING NORTH
AND ABOVE 32F SOUTH. AIR TEMPERATURES MAINLY IN THE LOWER TO MID
30S. WIND DRIVEN SNOW IS STILL EXPECTED TO CREATE HAZARDOUS
TRAVEL...ESPECIALLY WHEN WET ROADS REFREEZE AND/OR BLOWING SNOW
STARTS TO STICK THIS AFTERNOON. WILL MAINTAIN THE SPECIAL WEATHER
STATEMENT AS IS FOR NOW AND LET THE EVENING CREW DECIDE ITS FATE
AT THE 7PM UPDATE PERIOD.
TUESDAY MORNING/AFTERNOON LOOK TO BE RELATIVELY QUIET WITH PARTLY
CLOUDY SKIES AND DRY CONDITIONS. A WARM FRONT MOVING INTO
SOUTHEAST MONTANA WILL SEE TEMPERATURES WARMING TO NEAR 40 OVER MY
FAR SOUTHWEST CORNER. SHARP TEMPERATURE GRADIENT WITH HIGHS AROUND
15 ABOVE FOR THE TURTLE MOUNTAINS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 334 PM CST MON DEC 16 2013
THE MAIN FORECAST ISSUE IS SNOWFALL AMOUNTS AND COVERAGE WITH THE
MID WEEK STORM.
A LOW PRESSURE CLIPPER SYSTEM IS FORECAST TO DEVELOP TUESDAY OVER
ALBERTA AND MOVE EAST/SOUTHEAST TOWARDS NORTH DAKOTA TUESDAY NIGHT.
WINDS ACROSS THE FORECAST AREA SHOULD START OUT SOUTHERLY EARLY
TUESDAY EVENING...BECOMING WEST DURING THE EVENING/NIGHT WITH WARM
ADVECTION AS NORTH DAKOTA REMAINS IN THE WARM SECTOR OF THE SYSTEM.
ON WEDNESDAY THE CLIPPER LOW DEVELOPS INTO MORE OF A COLD FRONT IN
NATURE...MOVING SOUTH ACROSS THE STATE. IT APPEARS THAT THE MARKED
COLD ADVECTION WITH THE ARCTIC AIR BEGINS WEDNESDAY AROUND NOON IN
THE NORTH AND DURING THE AFTERNOON FARTHER SOUTH. HIGHS WEDNESDAY
SHOULD RANGE FROM THE UPPER TEENS/MID 20S NORTH TO THE UPPER 20S/30S
SOUTH. KEPT A SLIGHT CHANCE OF LIGHT SNOW IN THE NORTHWEST AND NORTH
CENTRAL NORTH DAKOTA ALONG THE ARCTIC COLD FRONT.
MODEL AGREEMENT CONTINUES TO IMPROVE REGARDING THE MAIN SYNOPTIC
FEATURES OF THE UPPER LEVEL TROUGH AND VORT ENERGY IMPULSES...AS
WELL AS THE POSITION OF THE COLD FRONT AND ARCTIC HIGH PRESSURE
SYSTEM. THE UPPER LEVEL TROUGH MOVES ACROSS NORTH DAKOTA
THURSDAY/THURSDAY EVENING. MEANWHILE THE SURFACE ARCTIC HIGH DIVES
SOUTH FROM ALBERTA INTO MONTANA WEDNESDAY NIGHT/THURSDAY. IN NORTH
DAKOTA...THE ARCTIC COLD FRONT MOVES SOUTH ACROSS THE STATE
WEDNESDAY AFTERNOON/EVENING WITH COLD ADVECTION CONTINUING THROUGH
THE DAY THURSDAY.
THE PLACEMENT OF SNOWFALL LOOKS TO BE HIGHEST IN MONTANA...BUT SNOW
ACCUMULATIONS ALONG THE NORTH DAKOTA/SOUTH DAKOTA BORDER SHOULD BE
IN THE 2-4 INCH RANGE. FOR WESTERN AND CENTRAL NORTH DAKOTA THE BULK
OF THE SNOWFALL SHOULD BEGIN WEDNESDAY NIGHT IN THE WEST...AND
EXPAND INTO CENTRAL NORTH DAKOTA AFTER MIDNIGHT WEDNESDAY
NIGHT/DAYBREAK THURSDAY MORNING...CONTINUE FOR MUCH OF THE
DAY THURSDAY...BEFORE TAPERING OFF IN THE JAMES RIVER VALLEY
THURSDAY EVENING.
VERY COLD AIR WILL ACCOMPANY THIS STORM SYSTEM WEDNESDAY NIGHT
THROUGH SATURDAY. SOME AREAS...ESPECIALLY THE NORTH...MAY HIT WIND
CHILL ADVISORY CRITERIA WEDNESDAY NIGHT AND THURSDAY NIGHT.
THE UPPER LEVEL PATTERN THROUGH THE WEEKEND CONTINUES NORTHWEST FLOW
ALOFT WITH A LARGE HUDSON BAY LOW IN PLACE. TOWARDS THE BEGINNING OF
NEXT WEEK THE MODELS ARE HINTING AT A MORE PROGRESSIVE PATTERN WITH
A WESTERN RIDGE BUILDING AND PUSHING THE HUDSON BAY LOW EASTWARD. NO
BIG WARM-UPS BUT NO BIG ARCTIC OUTBREAKS EITHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 932 PM CST MON DEC 16 2013
FOR THE 06 UTC TAF ISSUANCE...MAINLY VFR CLOUDS AND VISIBILITIES
EXPECTED THROUGH THE FORECAST PERIOD. ALTHOUGH A BRIEF MVFR
CEILING OR VISIBILITY IS CERTAINLY POSSIBLE IN ISOLATED SNOW
SHOWERS. MODERATE WEST FLOW WILL SLOWLY TAPER LATE TONIGHT.
LIGHTER WEST WINDS ON TUESDAY ACROSS THE AREA...WITH WINDS
BECOMING SOUTHERLY AT KISN AND KDIK AFTER 18 UTC TUESDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...NH
LONG TERM...JV
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
931 PM CST MON DEC 16 2013
.UPDATE...
ISSUED AT 930 PM CST MON DEC 16 2013
CURRENT RADAR SHOWING SNOW SHOWERS HAVE CLEARED MOST OF EASTERN ND
WITH EXCEPTION OF A SMALLER BATCH AROUND AND NORTH OF VALLEY CITY.
AS PER RUC...APPEARS SHOWERS ARE INTENSIFY SLIGHTLY SO KEPT SNOW
TOTALS IN THE HALF TO ONE INCH RANGE DESPITE RECEIVING VERY LITTLE
HERE IN GRAND FORKS. MAY SEE A LITTLE BETTER ACCUMULATION FROM
FOSSTON DOWN THROUGH PARK RAPIDS. ADJUSTED NORTHWARD THE LIKELY
POPS BASED ON LATEST TRENDS AND BEGAN LOWERING/REMOVING EARLIER
THE POPS WEST OF THE RIVER. RUC CONTINUES TO BRING A SECOND ROUND
OF LIGHT SHOWERS TO MY FAR NORTHEAST AND DID BRING IN SCATTERED
SHOWERS AFT 09Z FOR ROSEAU/LAKE OF THE WOODS. ALSO PUT PATCHY BLOWING
SNOW IN GRIDS FOR MOST OF NORTHEASTERN ND WEST OF THE VALLEY AS
WINDS IN DVL ARE GUSTING TO AROUND 32 KTS AND HAVE SEEN VSBYS GO
DOWN TO 3 MILES.
UPDATE ISSUED AT 648 PM CST MON DEC 16 2013
CHANGE OVER TO VCP 31 HELPING DETECT SOME SNOW SHOWERS MOVING
THROUGH THE NORTHEASTERN ND TO THE SOUTHEAST. SHOULD ARRIVE AT
GRAND FORKS OVER NEXT COUPLE OF HOURS AND PROCEED ON DOWN TO THE
DETROIT LAKES AREA AFTER MID EVENING. SOME WEAKER RETURNS OVER
NORTHERN VALLEY APPEAR TO BE MID LEVEL CLOUDS PER HALLOCK METAR.
DID INCREASE POPS HIGH CHANCE / SCATTERED COVERAGE THROUGH MID
EVENING THEN LIKELIES FOR THE LATE EVENING...EXPECTING THEM TO
INTENSIFY A BIT AS THEY ENTER WESTERN MN. DO EXPECT SHOWERS TO BE
THROUGH AREA BY 06Z BUT WILL KEEP INHERITED POPS AFTER MIDNIGHT
UNTIL NEW NAM DATA COMES IN. LAPS HAS A DECENT HANDLE ON TEMP
TRENDS...INCREASING FROM WEST TO EAST AS WESTERLY FLOW
CONTINUES...AND HAVE ADJUSTED HOURLIES THROUGH MIDNIGHT PER THE
LAPS. TEMPS STILL EXPECTED TO BE QUITE A BIT CHILLIER OVER THE
EAST VS THE BALMY WEST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 331 PM CST MON DEC 16 2013
AS EXPECTED WEST WINDS HAVE ARRIVED WITH TEMPS NR 30 IN ERN ND AND
THE RRV WITH WARMER AIR LAST TO ARRIVE IN NORTHERN MN. UPPER LOW
OVER NORTHWESTERN ONTARIO WILL TAP INTO SOME COLDER AIR IN
NORTHEASTERN MANITOBA TONIGHT AND BRING SOUTH SOME COLDER 850 MB
AIR INTO NW MN/FAR NE ND AFTER MIDNIGHT. SO WHILE THIS EVENING
WILL REMAIN MILD EXPECT A DECENT COOL DOWN AFTER 06Z. A SHORT WAVE
FROM SOUTHWESTERN SASK INTO SOUTH DAKOTA WILL BRING SOME - SN TO
ERN MT/SW ND INTO PARTS OF NRN SD/SRN MN TONIGHT. MORE SPOTTY LIGHT
SNOWS REST OF THE AREA AS A WEAKER SHORT WAVE MOVES SOUTHEAST
ACROSS SOUTHEAST SASK INTO THE RED RIVER VALLEY.
TUESDAY WILL SEE HIGH PRESSURE RIDGE BUILD IN AND SHOULD SEE A
FAIR AMOUNT OF SUN WITH HIGHS QUITE A BIT COLDER IN THE TEENS OR
LOWER 20S. COLD TUESDAY NIGHT IN NW MN WITH LOWS A BIT BELOW
ZERO....BUT CLOUDS MOVING IN IN WARM ADV WILL MEAN NOT AS COLD IN
ERN ND.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 331 PM CST MON DEC 16 2013
WEDNESDAY WILL SEE LOW PRESSURE MOVE NORTH OF THE BORDER. SOME
WARM ADV -SN MAY IMPACT LAKE OF THE WOODS....BUT MOSTLY NORTH OF
THE BORDER. OTHERWISE 850 MB TEMPS ACTUALLY WARMER WED THAN TODAY
WITH TEMPS IN THE ZERO NORTH TO +4C RANGE BUT WINDS LIGHTER AND
MORE SOUTHERLY AND THUS NOT QUITE THE WARM WIND. BUT STILL EXPECT
20S FOR MANY AREAS.
COLDER AIR WILL BEGIN TO DROP SOUTH BEHIND THE CANADIAN LOW LATE
WED NIGHT AND THEN PUSH SOUTH QUICKLY THURSDAY. NEXT SYSTEM WILL
MOVE EAST THRU SOUTH DAKOTA INTO SOUTHERN MN THURSDAY AFTN
SPREADING SOME SNOW ALONG THE SD/ND BORDER.
FOR THU NIGHT THE MODELS REMAIN IN GOOD AGREEMENT IN DEPICTING A
SHIFT WAVE SHIFTING INTO MN. WILL LINGER LIGHT SNOW CHANCES MAINLY
ALONG AND SOUTH OF THE HIGHWAY 2 CORRIDOR. 500MB FLOW THEN SHIFTS
BACK TO THE NORTHWEST WITH SFC HIGH PRESSURE FOR FRI. STILL NOT
LOOKING LIKE MUCH WEATHER WISE FRI NIGHT INTO SAT WITH MOST LIGHT
SNOW STAYING NORTH OF THE CANADIAN BORDER. BY SAT NIGHT INTO SUN
HIGH PRESSURE MOVES BACK IN WITH SOME CHILLY AIR ONCE AGAIN. LARGER
MODEL DIFFERENCES COME INTO PLAY BY MONDAY SO CONFIDENCE DROPS
CONSIDERABLY. GUIDANCE TEMPS SHOWING MONDAY HIGHS QUITE A BIT COOLER
THAN THE PRIOR MODEL RUN. WITH THE LOW CONFIDENCE WILL RUN WITH THE
GUIDANCE OUTPUT FOR MONDAY AND SEE WHAT LATER RUNS HAVE IN STORE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 648 PM CST MON DEC 16 2013
SHOULD SEE PREDOMINANTLY MVFR CIGS AS AREA OF SNOW SHOWERS MOVES
FROM NORTH OF DVL...TOWARD THE SOUTHEAST AND IN TO OTTER TAIL
COUNTY LATER THIS EVENING. WILL NEED TO ADJUST TAF FOR GFK AS
SHOWERS A BIT FURTHER NORTH THAN EXPECTED. MAY ALSO NOW MISS FAR.
BEST CHANCE FOR ANY PROLONGED TIME IN MVFR CIG CAT WILL BE TVF
AFTER INITIAL SHOT OF SNOW MOVES THROUGH. LATEST RUC GUIDANCE
SHOWS MORE LIGHT SNOW MOVING INTO NORTHWEST MINNESOTA LATER
TONIGHT. EXPECT TVF TO CLEAR OUT BRIEFLY BEFORE THE SECOND
ROUND...WITH CIGS DROPPING TO 2500 FT TO 3500 FT BY TOMORROW MORNING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...RIDDLE
LONG TERM...GODON/RIDDLE
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
648 PM CST MON DEC 16 2013
.UPDATE...
ISSUED AT 648 PM CST MON DEC 16 2013
CHANGE OVER TO VCP 31 HELPING DETECT SOME SNOW SHOWERS MOVING
THROUGH THE NORTHEASTERN ND TO THE SOUTHEAST. SHOULD ARRIVE AT
GRAND FORKS OVER NEXT COUPLE OF HOURS AND PROCEED ON DOWN TO THE
DETROIT LAKES AREA AFTER MID EVENING. SOME WEAKER RETURNS OVER
NORTHERN VALLEY APPEAR TO BE MID LEVEL CLOUDS PER HALLOCK METAR.
DID INCREASE POPS HIGH CHANCE / SCATTERED COVERAGE THROUGH MID
EVENING THEN LIKELIES FOR THE LATE EVENING...EXPECTING THEM TO
INTENSIFY A BIT AS THEY ENTER WESTERN MN. DO EXPECT SHOWERS TO BE
THROUGH AREA BY 06Z BUT WILL KEEP INHERITED POPS AFTER MIDNIGHT
UNTIL NEW NAM DATA COMES IN. LAPS HAS A DECENT HANDLE ON TEMP
TRENDS...INCREASING FROM WEST TO EAST AS WESTERLY FLOW
CONTINUES...AND HAVE ADJUSTED HOURLIES THROUGH MIDNIGHT PER THE
LAPS. TEMPS STILL EXPECTED TO BE QUITE A BIT CHILLIER OVER THE
EAST VS THE BALMY WEST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 331 PM CST MON DEC 16 2013
AS EXPECTED WEST WINDS HAVE ARRIVED WITH TEMPS NR 30 IN ERN ND AND
THE RRV WITH WARMER AIR LAST TO ARRIVE IN NORTHERN MN. UPPER LOW
OVER NORTHWESTERN ONTARIO WILL TAP INTO SOME COLDER AIR IN
NORTHEASTERN MANITOBA TONIGHT AND BRING SOUTH SOME COLDER 850 MB
AIR INTO NW MN/FAR NE ND AFTER MIDNIGHT. SO WHILE THIS EVENING
WILL REMAIN MILD EXPECT A DECENT COOL DOWN AFTER 06Z. A SHORT WAVE
FROM SOUTHWESTERN SASK INTO SOUTH DAKOTA WILL BRING SOME - SN TO
ERN MT/SW ND INTO PARTS OF NRN SD/SRN MN TONIGHT. MORE SPOTTY LIGHT
SNOWS REST OF THE AREA AS A WEAKER SHORT WAVE MOVES SOUTHEAST
ACROSS SOUTHEAST SASK INTO THE RED RIVER VALLEY.
TUESDAY WILL SEE HIGH PRESSURE RIDGE BUILD IN AND SHOULD SEE A
FAIR AMOUNT OF SUN WITH HIGHS QUITE A BIT COLDER IN THE TEENS OR
LOWER 20S. COLD TUESDAY NIGHT IN NW MN WITH LOWS A BIT BELOW
ZERO....BUT CLOUDS MOVING IN IN WARM ADV WILL MEAN NOT AS COLD IN
ERN ND.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 331 PM CST MON DEC 16 2013
WEDNESDAY WILL SEE LOW PRESSURE MOVE NORTH OF THE BORDER. SOME
WARM ADV -SN MAY IMPACT LAKE OF THE WOODS....BUT MOSTLY NORTH OF
THE BORDER. OTHERWISE 850 MB TEMPS ACTUALLY WARMER WED THAN TODAY
WITH TEMPS IN THE ZERO NORTH TO +4C RANGE BUT WINDS LIGHTER AND
MORE SOUTHERLY AND THUS NOT QUITE THE WARM WIND. BUT STILL EXPECT
20S FOR MANY AREAS.
COLDER AIR WILL BEGIN TO DROP SOUTH BEHIND THE CANADIAN LOW LATE
WED NIGHT AND THEN PUSH SOUTH QUICKLY THURSDAY. NEXT SYSTEM WILL
MOVE EAST THRU SOUTH DAKOTA INTO SOUTHERN MN THURSDAY AFTN
SPREADING SOME SNOW ALONG THE SD/ND BORDER.
FOR THU NIGHT THE MODELS REMAIN IN GOOD AGREEMENT IN DEPICTING A
SHIFT WAVE SHIFTING INTO MN. WILL LINGER LIGHT SNOW CHANCES MAINLY
ALONG AND SOUTH OF THE HIGHWAY 2 CORRIDOR. 500MB FLOW THEN SHIFTS
BACK TO THE NORTHWEST WITH SFC HIGH PRESSURE FOR FRI. STILL NOT
LOOKING LIKE MUCH WEATHER WISE FRI NIGHT INTO SAT WITH MOST LIGHT
SNOW STAYING NORTH OF THE CANADIAN BORDER. BY SAT NIGHT INTO SUN
HIGH PRESSURE MOVES BACK IN WITH SOME CHILLY AIR ONCE AGAIN. LARGER
MODEL DIFFERENCES COME INTO PLAY BY MONDAY SO CONFIDENCE DROPS
CONSIDERABLY. GUIDANCE TEMPS SHOWING MONDAY HIGHS QUITE A BIT COOLER
THAN THE PRIOR MODEL RUN. WITH THE LOW CONFIDENCE WILL RUN WITH THE
GUIDANCE OUTPUT FOR MONDAY AND SEE WHAT LATER RUNS HAVE IN STORE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 648 PM CST MON DEC 16 2013
SHOULD SEE PREDOMINANTLY MVFR CIGS AS AREA OF SNOW SHOWERS MOVES
FROM NORTH OF DVL...TOWARD THE SOUTHEAST AND IN TO OTTER TAIL
COUNTY LATER THIS EVENING. WILL NEED TO ADJUST TAF FOR GFK AS
SHOWERS A BIT FURTHER NORTH THAN EXPECTED. MAY ALSO NOW MISS FAR.
BEST CHANCE FOR ANY PROLONGED TIME IN MVFR CIG CAT WILL BE TVF
AFTER INITIAL SHOT OF SNOW MOVES THROUGH. LATEST RUC GUIDANCE
SHOWS MORE LIGHT SNOW MOVING INTO NORTHWEST MINNESOTA LATER
TONIGHT. EXPECT TVF TO CLEAR OUT BRIEFLY BEFORE THE SECOND
ROUND...WITH CIGS DROPPING TO 2500 FT TO 3500 FT BY TOMORROW MORNING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...RIDDLE
LONG TERM...GODON/RIDDLE
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
644 PM CST MON DEC 16 2013
.UPDATE...
ISSUED AT 644 PM CST MON DEC 16 2013
LATEST RADAR LOOP IS STILL SHOWING SOME LIGHT REFLECTIVITIES
ACROSS WESTERN AND CENTRAL NORTH DAKOTA...BUT LITTLE IN THE WAY OF
SURFACE REPORTS VIA OBSERVATIONS OR WEATHER CAMERAS. STILL KEPT
SOME POPS IN THE SOUTHWEST...HIGHEST EARLY THIS EVENING AND
TAPERING THROUGH LATE EVENING. ALSO SOME SNOW SHOWERS OVER ROLETTE
COUNTY SO BUMPED UP POPS OVER NORTHEAST ROLETTE FOR A COUPLE
HOURS. RAISED SKY COVER OVER THE SOUTHWEST AND GENERALLY BUMPED UP
SKY ACROSS THE AREA THROUGH THE EVENING AS THERE ARE QUITE A BIT
OF MID AND HIGH LEVEL CLOUDS TRAVERSING THE AREA IN NORTHWEST
FLOW.
RECEIVED QUITE A FEW RESPONSES VIA SOCIAL MEDIA ABOUT THE
SLIPPERY ROADS ACROSS MAINLY THE NORTH. WILL EXTEND THE SPS FOR
ICY CONDITIONS THROUGH THE EVENING HOURS AS WE WILL REMAIN BREEZY
AND TEMPERATURES DROP BELOW FREEZING.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY AFTERNOON)
ISSUED AT 334 PM CST MON DEC 16 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE AREAS OF
BLOWING/DRIFTING SNOW RESULTING IN POSSIBLE ICY ROADS/BLACK ICE
ACROSS THE NORTH THROUGH THIS EVENING...AND A CHANCE OF LIGHT SNOW
THIS AFTERNOON AND EVENING WEST TO EAST.
CURRENTLY...STRONG NORTHWEST FLOW ALOFT WITH A SHARP RIDGE OFF
THE WEST COAST AND A BROAD LONG WAVE TROUGH OVER THE EASTERN
UNITED STATES. UPPER LEVEL JET STREAM EXTENDS FROM THE TOP OF THE
RIDGE OVER ALASKA...SOUTHEAST INTO THE NORTHERN HIGH PLAINS OF
MT/WY. STRONG PRESSURE GRADIENT CONTINUES TO DEVELOP ACROSS WEST
AND CENTRAL NORTH DAKOTA WEST OF A SURFACE TROUGH OVER FAR WESTERN
MINNESOTA. GRADIENT FORCING WILL INCREASE THROUGHOUT THE DAY AND
INTO THIS EVENING AS THE TROUGH REMAINS QUASI-STATIONARY AND AS A
SURFACE HIGH BUILDS OFF TO OUR WEST CENTERED OVER THE NORTHEASTERN
SNAKE RIVER VALLEY OF EASTERN IDAHO.
MODELS EARLIER WERE LOOKING LIKE THEY WERE TRENDING TOWARDS A
CONSENSUS REGARDING PRECIPITATION CHANCES THIS AFTERNOON AND
EVENING. NOW NOT SO MUCH. MOISTURE IS HAVING A HARD TIME REACHING
THE GROUND ACROSS MY WEST CENTRAL. WEB CAMS OVER SOUTHWEST NORTH
DAKOTA DEFINITELY SHOWING SNOWFALL ALTHOUGH MOSTLY MELTING ON THE
ROAD SURFACES. BOWMAN RADAR STILL LIT UP...AND BAKER MT STILL
REPORTING SNOW. THE 12Z ECMWF AND LATEST RAP SEEM TO BE CAPTURING
REALITY THE BEST VERSUS OTHER GUIDANCE. LEANED IN THEIR DIRECTION
WITH LINGERING LIGHT PRECIPITATION SOUTHWEST NOW THROUGH THIS
EVENING...AND ANOTHER AREA OF LIGHT PRECIPITATION MOVING SOUTHEAST
OVER MY EASTERN COUNTIES LATE AFTERNOON AND EVENING. THIS AREA
CURRENTLY SHOWING UP ON RADAR OVER SOUTHEAST SK/SOUTHWEST
MANITOBA.
THE INCREASING PRESSURE GRADIENT WILL SEE WINDS INCREASE TO JUST
BELOW WIND ADVISORY CRITERIA MOST LOCATIONS NOW THROUGH THE
EVENING HOURS...BEFORE WINDING DOWN AFTER 06Z. AT THIS TIME WINDS
ARE SUSTAINED AT 15-25 MPH MOST LOCATIONS...WITH GUSTS AS HIGH AS
35 MPH REPORTED. ROAD SFC TEMPS REMAIN AT OR BELOW FREEZING NORTH
AND ABOVE 32F SOUTH. AIR TEMPERATURES MAINLY IN THE LOWER TO MID
30S. WIND DRIVEN SNOW IS STILL EXPECTED TO CREATE HAZARDOUS
TRAVEL...ESPECIALLY WHEN WET ROADS REFREEZE AND/OR BLOWING SNOW
STARTS TO STICK THIS AFTERNOON. WILL MAINTAIN THE SPECIAL WEATHER
STATEMENT AS IS FOR NOW AND LET THE EVENING CREW DECIDE ITS FATE
AT THE 7PM UPDATE PERIOD.
TUESDAY MORNING/AFTERNOON LOOK TO BE RELATIVELY QUIET WITH PARTLY
CLOUDY SKIES AND DRY CONDITIONS. A WARM FRONT MOVING INTO
SOUTHEAST MONTANA WILL SEE TEMPERATURES WARMING TO NEAR 40 OVER MY
FAR SOUTHWEST CORNER. SHARP TEMPERATURE GRADIENT WITH HIGHS AROUND
15 ABOVE FOR THE TURTLE MOUNTAINS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 334 PM CST MON DEC 16 2013
THE MAIN FORECAST ISSUE IS SNOWFALL AMOUNTS AND COVERAGE WITH THE
MID WEEK STORM.
A LOW PRESSURE CLIPPER SYSTEM IS FORECAST TO DEVELOP TUESDAY OVER
ALBERTA AND MOVE EAST/SOUTHEAST TOWARDS NORTH DAKOTA TUESDAY NIGHT.
WINDS ACROSS THE FORECAST AREA SHOULD START OUT SOUTHERLY EARLY
TUESDAY EVENING...BECOMING WEST DURING THE EVENING/NIGHT WITH WARM
ADVECTION AS NORTH DAKOTA REMAINS IN THE WARM SECTOR OF THE SYSTEM.
ON WEDNESDAY THE CLIPPER LOW DEVELOPS INTO MORE OF A COLD FRONT IN
NATURE...MOVING SOUTH ACROSS THE STATE. IT APPEARS THAT THE MARKED
COLD ADVECTION WITH THE ARCTIC AIR BEGINS WEDNESDAY AROUND NOON IN
THE NORTH AND DURING THE AFTERNOON FARTHER SOUTH. HIGHS WEDNESDAY
SHOULD RANGE FROM THE UPPER TEENS/MID 20S NORTH TO THE UPPER 20S/30S
SOUTH. KEPT A SLIGHT CHANCE OF LIGHT SNOW IN THE NORTHWEST AND NORTH
CENTRAL NORTH DAKOTA ALONG THE ARCTIC COLD FRONT.
MODEL AGREEMENT CONTINUES TO IMPROVE REGARDING THE MAIN SYNOPTIC
FEATURES OF THE UPPER LEVEL TROUGH AND VORT ENERGY IMPULSES...AS
WELL AS THE POSITION OF THE COLD FRONT AND ARCTIC HIGH PRESSURE
SYSTEM. THE UPPER LEVEL TROUGH MOVES ACROSS NORTH DAKOTA
THURSDAY/THURSDAY EVENING. MEANWHILE THE SURFACE ARCTIC HIGH DIVES
SOUTH FROM ALBERTA INTO MONTANA WEDNESDAY NIGHT/THURSDAY. IN NORTH
DAKOTA...THE ARCTIC COLD FRONT MOVES SOUTH ACROSS THE STATE
WEDNESDAY AFTERNOON/EVENING WITH COLD ADVECTION CONTINUING THROUGH
THE DAY THURSDAY.
THE PLACEMENT OF SNOWFALL LOOKS TO BE HIGHEST IN MONTANA...BUT SNOW
ACCUMULATIONS ALONG THE NORTH DAKOTA/SOUTH DAKOTA BORDER SHOULD BE
IN THE 2-4 INCH RANGE. FOR WESTERN AND CENTRAL NORTH DAKOTA THE BULK
OF THE SNOWFALL SHOULD BEGIN WEDNESDAY NIGHT IN THE WEST...AND
EXPAND INTO CENTRAL NORTH DAKOTA AFTER MIDNIGHT WEDNESDAY
NIGHT/DAYBREAK THURSDAY MORNING...CONTINUE FOR MUCH OF THE
DAY THURSDAY...BEFORE TAPERING OFF IN THE JAMES RIVER VALLEY
THURSDAY EVENING.
VERY COLD AIR WILL ACCOMPANY THIS STORM SYSTEM WEDNESDAY NIGHT
THROUGH SATURDAY. SOME AREAS...ESPECIALLY THE NORTH...MAY HIT WIND
CHILL ADVISORY CRITERIA WEDNESDAY NIGHT AND THURSDAY NIGHT.
THE UPPER LEVEL PATTERN THROUGH THE WEEKEND CONTINUES NORTHWEST FLOW
ALOFT WITH A LARGE HUDSON BAY LOW IN PLACE. TOWARDS THE BEGINNING OF
NEXT WEEK THE MODELS ARE HINTING AT A MORE PROGRESSIVE PATTERN WITH
A WESTERN RIDGE BUILDING AND PUSHING THE HUDSON BAY LOW EASTWARD. NO
BIG WARM-UPS BUT NO BIG ARCTIC OUTBREAKS EITHER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 644 PM CST MON DEC 16 2013
FOR THE 00 UTC TAF ISSUANCE...MAINLY VFR CLOUDS AND VISIBILITIES
EXPECTED THROUGH THE FORECAST PERIOD. ALTHOUGH A BRIEF MVFR
CEILING OR VISIBILITY IS CERTAINLY POSSIBLE IN ISOLATED SNOW
SHOWERS THIS EVENING. MODERATE WEST FLOW THIS EVENING WILL SLOWLY
TAPER LATE TONIGHT. LIGHTER WEST WINDS ON TUESDAY ACROSS THE
AREA...WITH WINDS BECOMING SOUTHERLY AT KISN AND KDIK AFTER 18 UTC
TUESDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...NH
LONG TERM...JV
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS PORTLAND OR
950 PM PST SAT DEC 14 2013
.SYNOPSIS...TODAY WAS A CHILLY...CLAMMY DECEMBER DAY FOR MUCH OF
SOUTHWEST WASHINGTON AND NORTHWEST OREGON...AS ABUNDANT LOW CLOUDS
AND FOG LINGER UNDER INCREASING HIGH CLOUDINESS ALOFT. AREAS OF
DRIZZLE OR LIGHT RAIN WILL INCREASE FROM THE NORTH LATER TONIGHT AND
SUNDAY AS A WEAK COLD FRONT MOVES ONSHORE. MONDAY AND TUESDAY SHOULD
BE DRIER AS HIGH PRESSURE MOVES IN OVER THE PACIFIC NORTHWEST...
THOUGH VALLEY FOG WILL PROBABLY LINGER NEAR EUGENE. A COLDER SYSTEM
IS EXPECTED TO BRING RAIN AND MOUNTAIN SNOW WEDNESDAY AND
THURSDAY...WITH MORE UNSETTLED WEATHER POSSIBLE FRIDAY.
&&
.UPDATE...HAVE ADDED A DENSE FOG ADVISORY FOR THE CENTRAL AND SOUTH VALLEY
FOR NOW...AS ENOUGH LOCATIONS CLOSE TO MAJOR ROADWAYS HAVE ONE QUARTER MILE
VISIBILITY OR LESS. /KMD
LOW CLOUDS AND FOG HANGING ON STRONG THIS EVENING...THOUGH
VISIBILITIES ARE ALL OVER THE BOARD... FROM ONE QUARTER MILE OR LESS
TO 6-8 MILES. EXPECT THAT THERE WILL BE SOME DENSE FOG AS THE LOW
LEVELS ARE FAIRLY STABLE AND IT IS CERTAINLY VERY MOIST...BUT WITH
THE INCOMING FRONT WE MAY HAVE JUST ENOUGH WIND TO PREVENT WIDESPREAD
DENSE FOG. THIS IS ESPECIALLY TRUE LATER TONIGHT AS THE FRONT GETS
CLOSER...AND THE HRRR SUGGESTS SOME IMPROVEMENT. THE MOST WIND IS
AROUND THE NORTH VALLEY. THE MESSAGE IS STILL THE SAME...QUITE A BIT
OF FOG...LOCALLY DENSE. FAVORED SPOTS FOR DENSE FOG WILL BE THOSE
THAT HAVE BEEN SEEING IT TO THIS POINT...EUGENE AIRPORT...
MCMINNVILLE...AURORA...AND HILLSBORO...AND ANY HIGHER HILLS THAT ARE
UP INTO THE VERY LOW STRATUS DECK. /KMD
.SHORT TERM...TONIGHT THROUGH TUESDAY...TODAY HAS BEEN A FAIRLY
TYPICAL DECEMBER DAY ACROSS SOUTHWEST WASHINGTON AND NORTHWEST
OREGON...WITH PATCHY FOG LINGERING WELL INTO THE AFTERNOON HOURS...
CHILLY TEMPERATURES AND HIGH RELATIVE HUMIDITY. THE LOW SUN ANGLE
COMBINED WITH INCREASING HIGH CLOUD COVER HAS DONE LITTLE TO BREAK UP
THE LOW CLOUDS WHICH FORMED IN THE VALLEYS OVERNIGHT. THEREFORE
TEMPERATURES HAVE STRUGGLED TO GET MUCH ABOVE 40 DEGREES FOR MOST
LOCATIONS...THOUGH A FEW FOOTHILL LOCATIONS ABOVE THE FOG/LOW CLOUDS
HAVE WARMED UP A LITTLE BETTER...INTO THE UPPER 40S AND LOWER 50S.
AS A SIDE NOTE...AS WE NEAR THE WINTER SOLSTICE...THE SUN ANGLE FOR
PORTLAND AT ITS PEAK OF SOLAR NOON IS ONLY ABOUT 22 DEGREES ABOVE THE
SOUTH HORIZON THIS TIME OF YEAR. HENCE THE LONG SHADOWS WHEN THE SUN
IS ACTUALLY OUT...AND THE LACK OF EFFECTIVENESS OF THE SUN AT WARMING
US UP AND DRYING US OUT THIS TIME OF YEAR.
ANYWAY...PATCHY DRIZZLE CONTINUES TO CAUSE SPOTTY ACCUMULATIONS OF
0.01 INCH HERE AND THERE IN THE COAST RANGE AND CASCADE FOOTHILLS...
NOT TO BE CONFUSED WITH SNOW MELTING INTO THE UNHEATED RAIN GAGES AT
THE HIGHER ELEVATIONS. DRIZZLE AND LIGHT RAIN SHOULD INCREASE FROM
THE NORTH LATER TONIGHT AND SUNDAY...ESPECIALLY IN THE COAST RANGE.
ONLY MINIMAL PRECIPITATION IF ANY IS EXPECTED FOR THE INLAND
VALLEYS...WITH THE BEST CHANCE NORTH. WITH MORE MOISTURE AND WEAK
FLOW...THERE SHOULD BE PLENTY OF LOW CLOUDS AND FOG AROUND AGAIN
SUNDAY. TEMPERATURES SUNDAY SHOULD BE A LOT LIKE TODAY...PERHAPS A
TOUCH WARMER DUE TO THE HIGHER DEWPOINT SUBTROPICAL AIR MOVING IN.
SNOW LEVELS WILL BE HIGH...SO SNOW IS NOT A CONCERN FOR THE CASCADE
PASSES.
MORE FOG SHOULD SETTLE IN SUN NIGHT/MON MORNING...BUT HIGH PRESSURE
IS EXPECTED TO BUILD INTO WASHINGTON BY MONDAY AFTERNOON. THIS IS
EXPECTED TO RESULT IN INCREASING NORTHERLY AND EVENTUALLY
NORTHEASTERLY FLOW MONDAY...POSSIBLY LEADING TO SOME DRYING AND
SUNBREAKS MOST AREAS BY AFTERNOON. THE NORTHERLY FLOW SHOULD CAUSE
THE LOW CLOUDS TO BANK UP AGAINST THE SOUTH END OF THE WILLAMETTE
VALLEY...LEADING TO ANOTHER CHILLY AND CLAMMY DAY AT EUGENE WITH
HIGHS AROUND 40 MONDAY WHILE MOST OTHER AREAS AIM FOR 50 DEGREES OR
A LITTLE HIGHER.
FOG AND LOW CLOUDS SHOULD BE A LITTLE LESS WIDESPREAD MON NIGHT/TUE
MORNING DUE TO THE OFFSHORE FLOW...EXCEPT IN THE SOUTH WILLAMETTE
VALLEY. HOWEVER INCREASING MID-HIGH LEVEL CLOUDS SHOULD KEEP
TEMPERATURES NEAR NORMAL...MAINLY IN THE 40S AND LOWER 50S...TUE
AFTERNOON. WEAGLE
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY. THE EXTENDED PERIOD
BEGINS WITH AN UPPER LEVEL TROUGH DROPPING DOWN THROUGH THE REGION
ALONG THE COAST. AN ASSOCIATED COLD FRONT WILL MOVE ACROSS THE AREA
ON WEDNESDAY ALONG WITH PRECIPITATION IN THE FORM OF WIDESPREAD RAIN
AND CASCADE SNOW. SNOW LEVELS WILL LOWER BEHIND THE FRONT WEDNESDAY
NIGHT AND SOME SHOWERS WILL LINGER INTO THURSDAY UNDER NORTHWEST
FLOW ALOFT. IT IS POSSIBLE THAT THE CASCADE FOOTHILLS AND COAST
RANGE MAY ALSO SEE SOME ACCUMULATING SNOW...THOUGH THIS WILL DEPEND
ON THE FROPA TIMING AND MOISTURE EXTENT.
BY THE END OF THE WEEK...THE RIDGE OF HIGH PRESSURE IN THE PACIFIC
IS CENTERED NEAR 140W KEEPING THE REGION UNDER NORTHWEST FLOW ALOFT.
LATE THURSDAY AFTERNOON AND NIGHT MAY BE DRY AHEAD OF THE NEXT
DISTURBANCE THAT WILL MOVE INTO THE AREA FROM THE NORTH ON FRIDAY OR
FRIDAY NIGHT. FORECAST MODEL AGREEMENT DECREASES AT THIS TIME...WITH
THE 12Z GFS KEEPING THE BULK OF THE MOISTURE TO THE NORTH WHILE THE
12Z ECMWF MOVES THE SYSTEM INTO THE AREA FASTER AND WITH A MORE
WIDESPREAD AREA OF PRECIPITATION. WHILE THE DETAILS REMAIN A BIT
UNCERTAIN...THE EXTENDED PERIOD GENERALLY WILL BE COOL AND WET
ACROSS THE FORECAST AREA. CULLEN
&&
.AVIATION...WIDESPREAD IFR TO LIFR THROUGHOUT THE COAST...COASTAL
VALLEYS AND INLAND VALLEYS. EXPECT THESE FLIGHT CONDITIONS TO
PREVAIL THROUGH TONIGHT AND SUNDAY MORNING. A WEAK FRONTAL SYSTEM
IS EXPECTED TO REACH THE S WA AND N OREGON COAST BETWEEN 09Z AND
12Z. THE FRONT WILL NOT BE STRONG ENOUGH TO CREATE SOME MIXING OF
THE LOW-LEVEL AIR MASS. EXPECT CONDITIONS TO AT LEAST IMPROVE TO
MVFR AFTER 18Z SUN. COAST RANGE AND CASCADES WILL REMAIN OBSCURED
THROUGH AT LEAST MID-AFTERNOON SUNDAY. SURFACE HIGH PRES AND
MOIST LOW-LEVEL AIR MASS SUN EVENING WILL RESULT IN WIDESPREAD
LOW-ELEVATION IFR TO MVFR BY 06Z MON.
KPDX AND APPROACHES...IFR AT THE TERMINAL AS OF 04Z AND CONDITIONS
SHOULD REMAIN THAT WAY THROUGH AT LEAST 12Z. LIGHT PRECIP EXPECTED
TO DEVELOP AROUND 12Z WHICH COULD REDUCE CONDITIONS TO LIFR...
POSSIBLY TO AIRPORT LANDING MINIMUMS. A GRADUAL IMPROVEMENT TO AT
LEAST MVFR TO OCCUR AROUND 18Z SUN. WEISHAAR
&&
.MARINE...WEAK FRONTAL SYSTEM MOVING INTO THE NRN COASTAL WATERS
AS OF 04Z WITH THE TRAILING COLD FRONT EXTENDING TO AROUND 44N
130W. WOULD HAVE EXPECTED 20-25 KT WIND AT BUOY 089 BY NOW...BUT
ONLY 10-15 KT. GUSTS TO 20 KT AT BUOY 029 AS OF 04Z. WILL MAINTAIN
THE CURRENT SMALL CRAFT ADVISORY FOR WIND...BUT A LITTLE LESS
CONFIDENT WIDESPREAD AND/OR FREQUENT GUSTS TO 25 KT WILL OCCUR
OVER THE NRN WATERS. WIND SPEEDS DROP OFF FAIRLY QUICKLY SUN
MORNING BEHIND THE FRONT AS SURFACE HIGH PRESSURE REBUILDS OVER
THE WATERS. A STORM SYSTEM DURING THE MIDDLE PART OF NEXT WEEK
WILL LIKELY NECESSITATE A SMALL CRAFT ADVISORY.
LATEST MODEL GUIDANCE STILL SHOWING SEAS REACHING 10 FT BY 18Z SUN
AS A LONGER-PERIOD SWELL TRAIN MOVES INTO THE WATERS. SPECTRAL
GUIDANCE FOR BUOY 029 SHOWS WAVE HEIGHTS PEAKING AT 13 FT LATE SUN
AFTERNOON AND CONTINUING THROUGH 06Z MON...THEN SLOWLY SUBSIDING.
HOWEVER...SEAS TO REMAIN AT OR ABOVE 10 FT THROUGH MON. WEISHAAR
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...DENSE FOG ADVISORY FOR THE CENTRAL WILLAMETTE VALLEY UNTIL 7 AM SUNDAY
DENSE FOG ADVISORY FOR THE SOUTH WILLAMETTE VALLEY UNTIL 10 AM SUNDAY.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 AM PST SUNDAY FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT
60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 10 AM SUNDAY TO
4 AM PST MONDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA
TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM NOON
TO 8 PM PST SUNDAY.
&&
$$
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 PORTLAND OR
841 PM PST SAT DEC 14 2013
.SYNOPSIS...TODAY WAS A CHILLY...CLAMMY DECEMBER DAY FOR MUCH OF
SOUTHWEST WASHINGTON AND NORTHWEST OREGON...AS ABUNDANT LOW CLOUDS
AND FOG LINGER UNDER INCREASING HIGH CLOUDINESS ALOFT. AREAS OF
DRIZZLE OR LIGHT RAIN WILL INCREASE FROM THE NORTH LATER TONIGHT AND
SUNDAY AS A WEAK COLD FRONT MOVES ONSHORE. MONDAY AND TUESDAY SHOULD
BE DRIER AS HIGH PRESSURE MOVES IN OVER THE PACIFIC NORTHWEST...
THOUGH VALLEY FOG WILL PROBABLY LINGER NEAR EUGENE. A COLDER SYSTEM
IS EXPECTED TO BRING RAIN AND MOUNTAIN SNOW WEDNESDAY AND
THURSDAY...WITH MORE UNSETTLED WEATHER POSSIBLE FRIDAY.
&&
.UPDATE...LOW CLOUDS AND FOG HANGING ON STRONG THIS EVENING...THOUGH
VISIBILITIES ARE ALL OVER THE BOARD... FROM ONE QUARTER MILE OR LESS
TO 6-8 MILES. EXPECT THAT THERE WILL BE SOME DENSE FOG AS THE LOW
LEVELS ARE FAIRLY STABLE AND IT IS CERTAINLY VERY MOIST...BUT WITH
THE INCOMING FRONT WE MAY HAVE JUST ENOUGH WIND TO PREVENT WIDESPREAD
DENSE FOG. THIS IS ESPECIALLY TRUE LATER TONIGHT AS THE FRONT GETS
CLOSER...AND THE HRRR SUGGESTS SOME IMPROVEMENT. THE MOST WIND IS
AROUND THE NORTH VALLEY. THE MESSAGE IS STILL THE SAME...QUITE A BIT
OF FOG...LOCALLY DENSE. FAVORED SPOTS FOR DENSE FOG WILL BE THOSE
THAT HAVE BEEN SEEING IT TO THIS POINT...EUGENE AIRPORT...
MCMINNVILLE...AURORA...AND HILLSBORO...AND ANY HIGHER HILLS THAT ARE
UP INTO THE VERY LOW STRATUS DECK. /KMD
.SHORT TERM...TONIGHT THROUGH TUESDAY...TODAY HAS BEEN A FAIRLY
TYPICAL DECEMBER DAY ACROSS SOUTHWEST WASHINGTON AND NORTHWEST
OREGON...WITH PATCHY FOG LINGERING WELL INTO THE AFTERNOON HOURS...
CHILLY TEMPERATURES AND HIGH RELATIVE HUMIDITY. THE LOW SUN ANGLE
COMBINED WITH INCREASING HIGH CLOUD COVER HAS DONE LITTLE TO BREAK UP
THE LOW CLOUDS WHICH FORMED IN THE VALLEYS OVERNIGHT. THEREFORE
TEMPERATURES HAVE STRUGGLED TO GET MUCH ABOVE 40 DEGREES FOR MOST
LOCATIONS...THOUGH A FEW FOOTHILL LOCATIONS ABOVE THE FOG/LOW CLOUDS
HAVE WARMED UP A LITTLE BETTER...INTO THE UPPER 40S AND LOWER 50S.
AS A SIDE NOTE...AS WE NEAR THE WINTER SOLSTICE...THE SUN ANGLE FOR
PORTLAND AT ITS PEAK OF SOLAR NOON IS ONLY ABOUT 22 DEGREES ABOVE THE
SOUTH HORIZON THIS TIME OF YEAR. HENCE THE LONG SHADOWS WHEN THE SUN
IS ACTUALLY OUT...AND THE LACK OF EFFECTIVENESS OF THE SUN AT WARMING
US UP AND DRYING US OUT THIS TIME OF YEAR.
ANYWAY...PATCHY DRIZZLE CONTINUES TO CAUSE SPOTTY ACCUMULATIONS OF
0.01 INCH HERE AND THERE IN THE COAST RANGE AND CASCADE FOOTHILLS...
NOT TO BE CONFUSED WITH SNOW MELTING INTO THE UNHEATED RAIN GAGES AT
THE HIGHER ELEVATIONS. DRIZZLE AND LIGHT RAIN SHOULD INCREASE FROM
THE NORTH LATER TONIGHT AND SUNDAY...ESPECIALLY IN THE COAST RANGE.
ONLY MINIMAL PRECIPITATION IF ANY IS EXPECTED FOR THE INLAND
VALLEYS...WITH THE BEST CHANCE NORTH. WITH MORE MOISTURE AND WEAK
FLOW...THERE SHOULD BE PLENTY OF LOW CLOUDS AND FOG AROUND AGAIN
SUNDAY. TEMPERATURES SUNDAY SHOULD BE A LOT LIKE TODAY...PERHAPS A
TOUCH WARMER DUE TO THE HIGHER DEWPOINT SUBTROPICAL AIR MOVING IN.
SNOW LEVELS WILL BE HIGH...SO SNOW IS NOT A CONCERN FOR THE CASCADE
PASSES.
MORE FOG SHOULD SETTLE IN SUN NIGHT/MON MORNING...BUT HIGH PRESSURE
IS EXPECTED TO BUILD INTO WASHINGTON BY MONDAY AFTERNOON. THIS IS
EXPECTED TO RESULT IN INCREASING NORTHERLY AND EVENTUALLY
NORTHEASTERLY FLOW MONDAY...POSSIBLY LEADING TO SOME DRYING AND
SUNBREAKS MOST AREAS BY AFTERNOON. THE NORTHERLY FLOW SHOULD CAUSE
THE LOW CLOUDS TO BANK UP AGAINST THE SOUTH END OF THE WILLAMETTE
VALLEY...LEADING TO ANOTHER CHILLY AND CLAMMY DAY AT EUGENE WITH
HIGHS AROUND 40 MONDAY WHILE MOST OTHER AREAS AIM FOR 50 DEGREES OR
A LITTLE HIGHER.
FOG AND LOW CLOUDS SHOULD BE A LITTLE LESS WIDESPREAD MON NIGHT/TUE
MORNING DUE TO THE OFFSHORE FLOW...EXCEPT IN THE SOUTH WILLAMETTE
VALLEY. HOWEVER INCREASING MID-HIGH LEVEL CLOUDS SHOULD KEEP
TEMPERATURES NEAR NORMAL...MAINLY IN THE 40S AND LOWER 50S...TUE
AFTERNOON. WEAGLE
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY. THE EXTENDED PERIOD
BEGINS WITH AN UPPER LEVEL TROUGH DROPPING DOWN THROUGH THE REGION
ALONG THE COAST. AN ASSOCIATED COLD FRONT WILL MOVE ACROSS THE AREA
ON WEDNESDAY ALONG WITH PRECIPITATION IN THE FORM OF WIDESPREAD RAIN
AND CASCADE SNOW. SNOW LEVELS WILL LOWER BEHIND THE FRONT WEDNESDAY
NIGHT AND SOME SHOWERS WILL LINGER INTO THURSDAY UNDER NORTHWEST
FLOW ALOFT. IT IS POSSIBLE THAT THE CASCADE FOOTHILLS AND COAST
RANGE MAY ALSO SEE SOME ACCUMULATING SNOW...THOUGH THIS WILL DEPEND
ON THE FROPA TIMING AND MOISTURE EXTENT.
BY THE END OF THE WEEK...THE RIDGE OF HIGH PRESSURE IN THE PACIFIC
IS CENTERED NEAR 140W KEEPING THE REGION UNDER NORTHWEST FLOW ALOFT.
LATE THURSDAY AFTERNOON AND NIGHT MAY BE DRY AHEAD OF THE NEXT
DISTURBANCE THAT WILL MOVE INTO THE AREA FROM THE NORTH ON FRIDAY OR
FRIDAY NIGHT. FORECAST MODEL AGREEMENT DECREASES AT THIS TIME...WITH
THE 12Z GFS KEEPING THE BULK OF THE MOISTURE TO THE NORTH WHILE THE
12Z ECMWF MOVES THE SYSTEM INTO THE AREA FASTER AND WITH A MORE
WIDESPREAD AREA OF PRECIPITATION. WHILE THE DETAILS REMAIN A BIT
UNCERTAIN...THE EXTENDED PERIOD GENERALLY WILL BE COOL AND WET
ACROSS THE FORECAST AREA. CULLEN
&&
.AVIATION...WIDESPREAD IFR TO LIFR THROUGHOUT THE COAST...COASTAL
VALLEYS AND INLAND VALLEYS. EXPECT THESE FLIGHT CONDITIONS TO
PREVAIL THROUGH TONIGHT AND SUNDAY MORNING. A WEAK FRONTAL SYSTEM
IS EXPECTED TO REACH THE S WA AND N OREGON COAST BETWEEN 09Z AND
12Z. THE FRONT WILL NOT BE STRONG ENOUGH TO CREATE SOME MIXING OF
THE LOW-LEVEL AIR MASS. EXPECT CONDITIONS TO AT LEAST IMPROVE TO
MVFR AFTER 18Z SUN. COAST RANGE AND CASCADES WILL REMAIN OBSCURED
THROUGH AT LEAST MID-AFTERNOON SUNDAY. SURFACE HIGH PRES AND
MOIST LOW-LEVEL AIR MASS SUN EVENING WILL RESULT IN WIDESPREAD
LOW-ELEVATION IFR TO MVFR BY 06Z MON.
KPDX AND APPROACHES...IFR AT THE TERMINAL AS OF 04Z AND CONDITIONS
SHOULD REMAIN THAT WAY THROUGH AT LEAST 12Z. LIGHT PRECIP EXPECTED
TO DEVELOP AROUND 12Z WHICH COULD REDUCE CONDITIONS TO LIFR...
POSSIBLY TO AIRPORT LANDING MINIMUMS. A GRADUAL IMPROVEMENT TO AT
LEAST MVFR TO OCCUR AROUND 18Z SUN. WEISHAAR
&&
.MARINE...WEAK FRONTAL SYSTEM MOVING INTO THE NRN COASTAL WATERS
AS OF 04Z WITH THE TRAILING COLD FRONT EXTENDING TO AROUND 44N
130W. WOULD HAVE EXPECTED 20-25 KT WIND AT BUOY 089 BY NOW...BUT
ONLY 10-15 KT. GUSTS TO 20 KT AT BUOY 029 AS OF 04Z. WILL MAINTAIN
THE CURRENT SMALL CRAFT ADVISORY FOR WIND...BUT A LITTLE LESS
CONFIDENT WIDESPREAD AND/OR FREQUENT GUSTS TO 25 KT WILL OCCUR
OVER THE NRN WATERS. WIND SPEEDS DROP OFF FAIRLY QUICKLY SUN
MORNING BEHIND THE FRONT AS SURFACE HIGH PRESSURE REBUILDS OVER
THE WATERS. A STORM SYSTEM DURING THE MIDDLE PART OF NEXT WEEK
WILL LIKELY NECESSITATE A SMALL CRAFT ADVISORY.
LATEST MODEL GUIDANCE STILL SHOWING SEAS REACHING 10 FT BY 18Z SUN
AS A LONGER-PERIOD SWELL TRAIN MOVES INTO THE WATERS. SPECTRAL
GUIDANCE FOR BUOY 029 SHOWS WAVE HEIGHTS PEAKING AT 13 FT LATE SUN
AFTERNOON AND CONTINUING THROUGH 06Z MON...THEN SLOWLY SUBSIDING.
HOWEVER...SEAS TO REMAIN AT OR ABOVE 10 FT THROUGH MON. WEISHAAR
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 AM PST SUNDAY FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT
60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 10 AM SUNDAY TO
4 AM PST MONDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA
TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM NOON
TO 8 PM PST SUNDAY.
&&
$$
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 STATE COLLEGE PA
546 PM EST SUN DEC 15 2013
.SYNOPSIS...
A CHILLY...AND GUSTY WESTERLY FLOW WILL KEEP PLENTY OF CLOUDS ACROSS
MUCH OF CENTRAL AND NORTHERN PENNSYLVANIA THIS AFTERNOON...WITH
OCCASIONAL LIGHT SNOW SHOWERS CONTINUING ACROSS THE NORTHERN AND
WESTERN MOUNTAINS. A DISTURBANCE AT UPPER LEVEL WILL MOVE SOUTHEAST
ACROSS THE GREAT LAKES TONIGHT INTO MONDAY BRINGING SOME LOCALIZED
LAKE EFFECT SNOWS TO THE SNOWBELT OF NORTHWESTERN PA. A STRONGER
DISTURBANCE WILL TRACK ACROSS THE LATE MONDAY NIGHT AND TUESDAY
BRINGING A WIDESPREAD LIGHT SNOWFALL TO AT LEAST CENTRAL AND
NORTHERN PENNSYLVANIA. HEIGHTS RISE THURSDAY INTO EARLY SATURDAY AND
THERE SHOULD BE A PERIOD OF RELATIVELY WARM WEATHER LATER THIS WEEK.
AFTER THAT...A DEVELOPING TROUGH SHOULD BRING A PERIOD OF RAIN OR
MIXED PRECIPITATION LATE NEXT WEEKEND INTO EARLY THE FOLLOWING
WEEK...FOLLOWED BY ANOTHER PUSH COLD AIR
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
A WELL-DEFINED UPPER LEVEL SHORTWAVE WAS LOCATED OVER THE U.P.
OF MICHIGAN...AND HEADED SE. 1004MB SFC LOW OVER NRN LAKE HURON HAS
A SWD TRAILING COLD FRONT. THE SFC FLOW WILL BACK PERHAPS ANOTHER
10-20 DEG /TO THE WSW/ LATE TDY AND THIS EVENING AHEAD OF THE
CFRONT. MDTLY STRONG WESTERLY FLOW AND WEAK ISENTROPIC LIFT /FOCUSED
IN THE 275-285K THETA LAYER/ AHEAD OF THESE FEATURES WILL HELP TO
MAINTAIN A SEVERAL DEG C INVERSION BETWEEN 4-7 KFT AGL...RESULTING
IN EXTENSIVE/WIDESPREAD THICK STRATOCU ACROSS MOST OF THE REGION
/EXCEPT FOR THE LOWER SUSQ VALLEY WHERE SOME FLEETING BREAKS OF SUN
WILL OCCUR LATE THIS AFTERNOON/.
THE FAIRLY STEADY LIGHT SNOW THAT/S BEEN PREVALENT TODAY ACROSS THE
NRN AND WRN MTNS OF THE STATE SHOULD AMOUNT TO BETWEEN A COATING AND
1.5 INCHES WITH SFC VSBYS MAINLY IN THE 1-2SM RANGE NEAR AND JUST TO
THE EAST OF THE ROUTE 219 CORRIDOR FROM KBFD TO KJST. OCCASIONAL
VERY LIGHT SNOW WITH VSBYS OF 4-5SM WILL CONTINUE SPILL OVER INTO
THE CENTRAL RIDGE AND VALLEY REGION AS THIS AREA OF WEAK ISENTROPIC
LIFT SPREADS EWD...BRINGING A DUSTING OF SNOW TO SOME AREAS.
THE COLD AIR MOVING OVER THE LAKES BEHIND THIS FRONT AND A
WELL-ALIGNED 270-280 DEG BLYR FLOW WILL KICK OFF LAKE EFFECT SNOW
SHOWERS AND A FEW LOCALIZED HEAVY SNOW BANDS /FIRST ALONG THE I-90
CORRIDOR...THEN SHIFTING SLOWLY SEWRD LATE TODAY AND TONIGHT/. THE
HIGH RESOLUTION RAP AND 4KM NAM/ARW EACH SHOW THIS EVOLUTION LATER
THIS AFTERNOON AND OVERNIGHT.
MID TO LATE AFTERNOON TEMPS WILL VARY FROM MAINLY THE MID 20S ACROSS
THE MTNS TO THE MID 30S THROUGHOUT THE MIDDLE AND LOWER SUSQ VALLEY.
LAKE EFFECT AND COLD WILL BE THE TWO PRIMARY FORECAST ISSUES WITH A
BRISK WEST TO NORTHWEST WIND IN THE MORNING.
THE HIGH RESOLUTION MODELS IMPLY A SINGLE LAKE SHORE PARALLEL SNOW
BAND WHICH SHOULD BECOME MORE EAST-WEST WITH TIME THIS EVENING AS IT
DRIFTS INTO WARREN COUNTY AND LIKELY THE NW HALF MCKEAN COUNTY A FEW
HOURS AFTERWARD.
EXPANDED THE WINTER WEATHER ADVISORY TO MCKEAN COUNTY FOR LATE THIS
EVENING THROUGH 15Z MONDAY...AS THE MODERATELY STRONG MEAN BLYR FLOW
VEERS ABOUT 20-30 DEG...BACK TO A 270-280 DIRECTION. THIS TYPE OF
STEADY STATE WNW FLOW TYPICALLY SUPPORTS A LONGER DURATION/SINGLE
LES BAND THAT CAN PENETRATE FAIRLY FAR INLAND. A LIGHT COATING OF
SNOW IS POSSIBLE LATER TONIGHT AND MONDAY MORNING IN THE KIPT AREA
WITH SOME PTS TO THE NORTH AND EAST SEEING A QUICK HALF INCH TO
ONE-INCH.
THE FCST SNOW AMOUNTS EMPLOY A BLEND OF HIGH RESOLUTION MODELS AND
ANTICIPATED SNOWFALL RATES AND RESIDENCE TIME OF THE SNOWBANDS USING
MEAN SFC-875MB WIND OFF THE RAP AND NAM BUFKIT PROFILES.
MEAN SNOWFALL FOR WARREN CTY IS IN THE 3-6 INCH RANGE...WHILE 2-4
INCHES IS LIKELY ACROSS THE NW HALF OF MCKEAN COUNTY/.
THE NAM IMPLIES AN EXTENSIVE QUASI-SINGLE BAND STRUCTURE PENETRATING
FAR INLAND ACROSS THE NRN TIER COUNTIES...AND PERHAPS THROUGH
SULLIVAN CTY ON TWD THE POCONOS.
THIS SIMULATION AND THE RAP MAKE IT CLEAR BOTH FORECAST SYSTEMS
THINK THERE SHOULD BE A GOOD LES BAND IN SOUTHERN NY AND NW PA
OVERNIGHT TONIGHT.
OUTSIDE THE LES AND UPSLOPE SNOW AREAS...IT WILL BE A VERY COLD
EVENING AND OVERNIGHT WITH GUSTY WINDS...TO AROUND 30 MPH AT TIMES.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
WEAK RIDGING SLIDES OVER THE AREA BENEATH THE FAST WESTERLY FLOW
ALOFT. LAKE EFFECT SNOW SHOWERS WILL DECREASE IN INTENSITY AND
BECOME MORE MULTI-BANDED ACROSS THE NW MTNS IN THE MORNING...BEFORE
LIFTING NORTH AND DIMINISHING DURING THE AFTERNOON.
IT/LL BE QUITE COLD MONDAY WITH MAX TEMPS ONLY IN THE UPPER TEENS TO
LOWER 20S ACROSS THE MTNS...AND MID TO UPPER 20S IN THE SUSQ VALLEY.
THESE TEMPS WILL BE ABOUT 15F BELOW NORMAL.
SIGNIFICANT BREAKS IN THE STRATO CU WILL DEVELOP ACROSS THE CENTRAL
AND SE ZONES MONDAY WHILE SKY COVER STAYS BKN-OVC ACROSS THE LAURELS
AND NW MTNS DUE TO LLVL UPSLOPE FLOW AND THICKER MID/HIGH CLOUDS
SPREADING IN LATE AHEAD OF A POTENT CLIPPER.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
THE GEFS-CMCEPS-SREF ALL SHOWS A CLIPPER PASSING TO OUR NORTH
TUESDAY. TIMING VARIES AND TRACK IS TO OUR NORTH THUS ANY
PRECIPITATION SHOULD BE LIGHT. TRIED TO SHOW THE POTENTIAL FOR
LIGHT SNOW TUESDAY. KEPT SNOW GENERALLY LOWER THAN 1 INCH AND
MAINLY CENTRAL AND NORTHERN AREAS.
THE NW FLOW WEAKENS AS A 500 HPA LOW DEVELOPS IN SW US LATER IN
THE WEEK. THIS ALLOWS FOR SOUTHWESTERLY FLOW AND A GRADUAL WARM UP
LIKELY THURSDAY INTO FRIDAY. MODELS IMPLY WARMEST DAY WOULD BE
FRIDAY. THIS WILL NOT LAST AS MODELS SHOWS DEEPENING TROUGH TO OUR
NORTH AND WEST AND A POOL OF ARCTIC AIR MOVING INTO THE LAKES
FRIDAY INTO SATURDAY. THUS SURFACE COLD FRONT SHOULD PUSH COLD AIR
BACK INTO OUR REGION SOMETIME NEXT WEEKEND.
BIAS CORRECT GEFS AND NAEFS SUGGEST TROUGH AND GENERALLY COLD
WEATHER SETTLE BACK IN THIS COMING WEEKEND AND INTO THE CHRISTMAS
WEEK.
AT THIS TIME NO BIG STORMS IN THE ENSEMBLES.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
15/21Z...A FAST AND PERSISTENT WEST-NORTHWEST FLOW ALOFT WITH
A SERIES OF EMBEDDED CLIPPER SYSTEMS WILL RESULT IN WIDESPREAD
MVFR CIGS AND MVFR-IFR VISBYS AT BFD/JST...WITH OCNL MVFR-IFR
CONDS FURTHER EAST ACRS THE CENTRAL AND EASTERN AIRFIELDS. MUCH
OF THE AIRSPACE COULD SEE -SN AND ASSOCD MVFR TO IFR VIS MON NGT-
TUE NGT. IMPROVING CONDS SHOULD ARRIVE LATER WED INTO THUR AS HIGH
PRESSURE EXPANDS OVER THE REGION. ANOTHER FRONTAL SYSTEM SHOULD
ARRIVE BY FRIDAY WITH TEMPERATURES INITIALLY WARM ENOUGH FOR
RAIN.
OUTLOOK...
MON...MAINLY VFR CENTRAL/EAST. MVFR-IFR IN SHSN AT BFD/JST.
MON NITE-TUE NGT...WDSPRD LGT SNOW/REDUCED VSBYS POSSIBLE.
WED-THU...SHSN/REDUCED VSBYS WEST BCMG VFR. VFR ELSEWHERE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY FROM 9 PM THIS EVENING TO 10 AM EST
MONDAY FOR PAZ005.
LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST MONDAY FOR PAZ004.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...GRUMM/CERU
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
255 PM EST SUN DEC 15 2013
.SYNOPSIS...
A CHILLY...AND GUSTY WESTERLY FLOW WILL KEEP PLENTY OF CLOUDS ACROSS
MUCH OF CENTRAL AND NORTHERN PENNSYLVANIA THIS AFTERNOON...WITH
OCCASIONAL LIGHT SNOW SHOWERS CONTINUING ACROSS THE NORTHERN AND
WESTERN MOUNTAINS. A DISTURBANCE AT UPPER LEVEL WILL MOVE SOUTHEAST
ACROSS THE GREAT LAKES TONIGHT INTO MONDAY BRINGING SOME LOCALIZED
LAKE EFFECT SNOWS TO THE SNOWBELT OF NORTHWESTERN PA. A STRONGER
DISTURBANCE WILL TRACK ACROSS THE LATE MONDAY NIGHT AND TUESDAY
BRINGING A WIDESPREAD LIGHT SNOWFALL TO AT LEAST CENTRAL AND
NORTHERN PENNSYLVANIA. HEIGHTS RISE THURSDAY INTO EARLY SATURDAY AND
THERE SHOULD BE A PERIOD OF RELATIVELY WARM WEATHER LATER THIS WEEK.
AFTER THAT...A DEVELOPING TROUGH SHOULD BRING A PERIOD OF RAIN OR
MIXED PRECIPITATION LATE NEXT WEEKEND INTO EARLY THE FOLLOWING
WEEK...FOLLOWED BY ANOTHER PUSH COLD AIR
&&
.NEAR TERM /THROUGH TONIGHT/...
A WELL-DEFINED UPPER LEVEL SHORTWAVE WAS LOCATED OVER THE U.P.
OF MICHIGAN...AND HEADED SE. 1004MB SFC LOW OVER NRN LAKE HURON HAS
A SWD TRAILING COLD FRONT. THE SFC FLOW WILL BACK PERHAPS ANOTHER
10-20 DEG /TO THE WSW/ LATE TDY AND THIS EVENING AHEAD OF THE
CFRONT. MDTLY STRONG WESTERLY FLOW AND WEAK ISENTROPIC LIFT /FOCUSED
IN THE 275-285K THETA LAYER/ AHEAD OF THESE FEATURES WILL HELP TO
MAINTAIN A SEVERAL DEG C INVERSION BETWEEN 4-7 KFT AGL...RESULTING
IN EXTENSIVE/WIDESPREAD THICK STRATOCU ACROSS MOST OF THE REGION
/EXCEPT FOR THE LOWER SUSQ VALLEY WHERE SOME FLEETING BREAKS OF SUN
WILL OCCUR LATE THIS AFTERNOON/.
THE FAIRLY STEADY LIGHT SNOW THAT/S BEEN PREVALENT TODAY ACROSS THE
NRN AND WRN MTNS OF THE STATE SHOULD AMOUNT TO BETWEEN A COATING AND
1.5 INCHES WITH SFC VSBYS MAINLY IN THE 1-2SM RANGE NEAR AND JUST TO
THE EAST OF THE ROUTE 219 CORRIDOR FROM KBFD TO KJST. OCCASIONAL
VERY LIGHT SNOW WITH VSBYS OF 4-5SM WILL CONTINUE SPILL OVER INTO
THE CENTRAL RIDGE AND VALLEY REGION AS THIS AREA OF WEAK ISENTROPIC
LIFT SPREADS EWD...BRINGING A DUSTING OF SNOW TO SOME AREAS.
THE COLD AIR MOVING OVER THE LAKES BEHIND THIS FRONT AND A
WELL-ALIGNED 270-280 DEG BLYR FLOW WILL KICK OFF LAKE EFFECT SNOW
SHOWERS AND A FEW LOCALIZED HEAVY SNOW BANDS /FIRST ALONG THE I-90
CORRIDOR...THEN SHIFTING SLOWLY SEWRD LATE TODAY AND TONIGHT/. THE
HIGH RESOLUTION RAP AND 4KM NAM/ARW EACH SHOW THIS EVOLUTION LATER
THIS AFTERNOON AND OVERNIGHT.
MID TO LATE AFTERNOON TEMPS WILL VARY FROM MAINLY THE MID 20S ACROSS
THE MTNS TO THE MID 30S THROUGHOUT THE MIDDLE AND LOWER SUSQ VALLEY.
LAKE EFFECT AND COLD WILL BE THE TWO PRIMARY FORECAST ISSUES WITH A
BRISK WEST TO NORTHWEST WIND IN THE MORNING.
THE HIGH RESOLUTION MODELS IMPLY A SINGLE LAKE SHORE PARALLEL SNOW
BAND WHICH SHOULD BECOME MORE EAST-WEST WITH TIME THIS EVENING AS IT
DRIFTS INTO WARREN COUNTY AND LIKELY THE NW HALF MCKEAN COUNTY A FEW
HOURS AFTERWARD.
EXPANDED THE WINTER WEATHER ADVISORY TO MCKEAN COUNTY FOR LATE THIS
EVENING THROUGH 15Z MONDAY...AS THE MODERATELY STRONG MEAN BLYR FLOW
VEERS ABOUT 20-30 DEG...BACK TO A 270-280 DIRECTION. THIS TYPE OF
STEADY STATE WNW FLOW TYPICALLY SUPPORTS A LONGER DURATION/SINGLE
LES BAND THAT CAN PENETRATE FAIRLY FAR INLAND. A LIGHT COATING OF
SNOW IS POSSIBLE LATER TONIGHT AND MONDAY MORNING IN THE KIPT AREA
WITH SOME PTS TO THE NORTH AND EAST SEEING A QUICK HALF INCH TO
ONE-INCH.
THE FCST SNOW AMOUNTS EMPLOY A BLEND OF HIGH RESOLUTION MODELS AND
ANTICIPATED SNOWFALL RATES AND RESIDENCE TIME OF THE SNOWBANDS USING
MEAN SFC-875MB WIND OFF THE RAP AND NAM BUFKIT PROFILES.
MEAN SNOWFALL FOR WARREN CTY IS IN THE 3-6 INCH RANGE...WHILE 2-4
INCHES IS LIKELY ACROSS THE NW HALF OF MCKEAN COUNTY/.
THE NAM IMPLIES AN EXTENSIVE QUASI-SINGLE BAND STRUCTURE PENETRATING
FAR INLAND ACROSS THE NRN TIER COUNTIES...AND PERHAPS THROUGH
SULLIVAN CTY ON TWD THE POCONOS.
THIS SIMULATION AND THE RAP MAKE IT CLEAR BOTH FORECAST SYSTEMS
THINK THERE SHOULD BE A GOOD LES BAND IN SOUTHERN NY AND NW PA
OVERNIGHT TONIGHT.
OUTSIDE THE LES AND UPSLOPE SNOW AREAS...IT WILL BE A VERY COLD
EVENING AND OVERNIGHT WITH GUSTY WINDS...TO AROUND 30 MPH AT TIMES.
&&
.SHORT TERM /MONDAY/...
WEAK RIDGING SLIDES OVER THE AREA BENEATH THE FAST WESTERLY FLOW
ALOFT. LAKE EFFECT SNOW SHOWERS WILL DECREASE IN INTENSITY AND
BECOME MORE MULTI-BANDED ACROSS THE NW MTNS IN THE MORNING...BEFORE
LIFTING NORTH AND DIMINISHING DURING THE AFTERNOON.
IT/LL BE QUITE COLD MONDAY WITH MAX TEMPS ONLY IN THE UPPER TEENS TO
LOWER 20S ACROSS THE MTNS...AND MID TO UPPER 20S IN THE SUSQ VALLEY.
THESE TEMPS WILL BE ABOUT 15F BELOW NORMAL.
SIGNIFICANT BREAKS IN THE STRATO CU WILL DEVELOP ACROSS THE CENTRAL
AND SE ZONES MONDAY WHILE SKY COVER STAYS BKN-OVC ACROSS THE LAURELS
AND NW MTNS DUE TO LLVL UPSLOPE FLOW AND THICKER MID/HIGH CLOUDS
SPREADING IN LATE AHEAD OF A POTENT CLIPPER.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
THE GEFS-CMCEPS-SREF ALL SHOWS A CLIPPER PASSING TO OUR NORTH
TUESDAY. TIMING VARIES AND TRACK IS TO OUR NORTH THUS ANY
PRECIPITATION SHOULD BE LIGHT. TRIED TO SHOW THE POTENTIAL FOR
LIGHT SNOW TUESDAY. KEPT SNOW GENERALLY LOWER THAN 1 INCH AND
MAINLY CENTRAL AND NORTHERN AREAS.
THE NW FLOW WEAKENS AS A 500 HPA LOW DEVELOPS IN SW US LATER IN
THE WEEK. THIS ALLOWS FOR SOUTHWESTERLY FLOW AND A GRADUAL WARM UP
LIKELY THURSDAY INTO FRIDAY. MODELS IMPLY WARMEST DAY WOULD BE
FRIDAY. THIS WILL NOT LAST AS MODELS SHOWS DEEPENING TROUGH TO OUR
NORTH AND WEST AND A POOL OF ARCTIC AIR MOVING INTO THE LAKES
FRIDAY INTO SATURDAY. THUS SURFACE COLD FRONT SHOULD PUSH COLD AIR
BACK INTO OUR REGION SOMETIME NEXT WEEKEND.
BIAS CORRECT GEFS AND NAEFS SUGGEST TROUGH AND GENERALLY COLD
WEATHER SETTLE BACK IN THIS COMING WEEKEND AND INTO THE CHRISTMAS
WEEK.
AT THIS TIME NO BIG STORMS IN THE ENSEMBLES.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
DEEP WESTERLY FLOW AND EXTENSIVE BUT GENERALLY VERY WEAK UPWARD
MOTION IN THE LOW-MID LEVELS WILL MAINTAIN WIDESPREAD MVFR TO OCNL
IFR CIGS AND VSBYS IN LIGHT SNOW ACROSS THE CENTRAL AND NW
MTNS.
MAINLY VFR BKN-OVC CIGS WILL CONTINUE THROUGHOUT THE LOWER SUSQ
VALLEY THIS AFTERNOON. THE WIND WILL BE THE MAIN STORY FOR MOST
CENTRAL AND WESTERN PENN AIRFIELDS TODAY. SUSTAINED 12-17KTS WITH
GUSTS INTO THE MID/UPPER 20KT RANGE. THE ELEVATION AT JST WILL KEEP
THEM ON THE HIGHER-END OF WIND SPEEDS TODAY. LAKE EFFECT SHSN GO
INTO HIGH GEAR LATER THIS EVENING...AND BFD COULD BE IN FOR A LONG
NIGHT OF IFR SNOW AND CIGS.
WINDS /AND GUSTS/ WILL BE SEVERAL TO 10KTS LOWER AT KIPT AND KMDT
BEFORE INCREASING BY LATE THIS EVENING AS THE LLVL PRESSURE GRADIENT
TIGHTENS UP.
FAST FLOW WILL BRING A SERIES OF NRN STREAM IMPULSES OVER THE NEXT
SEVERAL DAYS...AND HELP TO MAINTAIN FREQUENT SHSN FOR THE WRN
TERMINALS FOR THE BULK OF THE WEEK. THE STRONGEST CLIPPER WILL BE ON
MON PM-TUE AM...WITH A SEVERAL HOUR PERIOD OF MVFR TO OCNL IFR
POSSIBLE IN STEADY LIGHT 3/4-1 1/2SM SNOW AT MANY CENTRAL AND NRN
PA TAF SITES. SOMEWHAT WARMER AIR AN IMPROVING FLYING CONDITION
ATTEMPT TO RETURN FOR THURSDAY...BEFORE A FRONTAL BOUNDARY AND
DOWNTREND IMPLYING CONDITIONS OCCURS HEADING INTO NEXT WEEKEND.
OUTLOOK...
MON...MAINLY VFR WITH MVFR TO IFR IN SHSN AT BFD. MVFR ALSO LIKELY
AT KJST.
MON NITE-TUE...LGT SNOW/REDUCED VSBYS. POSSIBLE BRIEF PERIODS OF
MDTLY HEAVY SNOW/SQUALLS ACCOMPANIED BY LIFR-VLIFR.
WED-THU...SHSN/REDUCED VSBYS POSS NW MTNS. MAINLY VFR ELSEWHERE
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY FROM 9 PM THIS EVENING TO 10 AM EST
MONDAY FOR PAZ005.
LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST MONDAY FOR PAZ004.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...GRUMM/CERU
AVIATION...LAMBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1151 AM EST SUN DEC 15 2013
.SYNOPSIS...
A CHILLY...AND GUSTY WESTERLY FLOW WILL KEEP PLENTY OF CLOUDS ACROSS
MUCH OF CENTRAL AND NORTHERN PENNSYLVANIA THIS AFTERNOON...WITH
OCCASIONAL LIGHT SNOW SHOWERS CONTINUING ACROSS THE NORTHERN AND
WESTERN MOUNTAINS. A DISTURBANCE AT UPPER LEVEL WILL MOVE SOUTHEAST
ACROSS THE GREAT LAKES TONIGHT INTO MONDAY BRINGING SOME LOCALIZED
LAKE EFFECT SNOWS TO THE SNOWBELT OF NORTHWESTERN PA. A STRONGER
DISTURBANCE WILL TRACK ACROSS THE LATE MONDAY NIGHT AND TUESDAY
BRINGING A WIDESPREAD LIGHT SNOWFALL TO AT LEAST CENTRAL AND
NORTHERN PENNSYLVANIA. HEIGHTS RISE THURSDAY INTO EARLY SATURDAY AND
THERE SHOULD BE A PERIOD OF RELATIVELY WARM WEATHER LATER THIS WEEK.
AFTER THAT...A DEVELOPING TROUGH SHOULD BRING A PERIOD OF RAIN OR
MIXED PRECIPITATION LATE NEXT WEEKEND INTO EARLY THE FOLLOWING
WEEK...FOLLOWED BY ANOTHER PUSH COLD AIR
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
INCREASINGLY WEST TO NWRLY FLOW /IN THE WAKE OF THE DEPARTING STORM
THAT BROUGHT WIDESPREAD SNOW THEN SOME ICE SATURDAY AND SATURDAY
NIGHT/ WILL PREVAIL TODAY...LEADING TO PERSISTENT LIGHT SNOW OR SNOW
SHOWERS ACROSS THE WESTERN HIGH TERRAIN THROUGH TODAY.
THE MEAN LLVL FLOW WILL BACK BY ABOUT 20-30 DEGREES THIS AFTERNOON
WELL IN ADVANCE OF A SHORTWAVE HEADED SE FROM THE NRN GLAKES REGION.
THE WEAK WSW LLVL ISENTROPIC LIFT AHEAD OF THIS FEATURE WILL HELP TO
STRENGTHEN THE INVERSION BETWEEN 4-7 KFT AGL KEEPING
EXTENSIVE/WIDESPREAD THICK STRATOCU LOCKED IN ACROSS MOST OF THE
REGION /EXCEPT FOR THE LOWER SUSQ VALLEY WHERE AT LEAST PARTLY SUNNY
SKIES WILL OCCUR THIS AFTERNOON.
THE FAIRLY STEADY LIGHT SNOW TODAY ACROSS THE NRN AND WRN MTNS OF
THE STATE SHOULD AMOUNT TO BETWEEN A COATING AND 1.5 INCHES WITH SFC
VSBYS MAINLY IN THE 1-3SM RANGE NEAR AND JUST TO THE EAST OF THE
ROUTE 219 CORRIDOR FROM KBFD TO KJST. OCCASIONAL VERY LIGHT SNOW
WITH VSBYS OF 3-5SM WILL SPILL OVER INTO THE CENTRAL RIDGE AND
VALLEY REGION AS THIS AREA OF WEAK..ALBEIT DEEPENING ISENTROPIC LIFT
SPREADS EWD THIS AFTERNOON...BRINGING A GOOD DUSTING OF
SNOW.
THE COLD AIR MOVING OVER THE LAKES BEHIND THIS FRONT WILL KICK OFF
LAKE EFFECT SNOW SHOWERS AND SNOW BANDS /FIRST ALONG THE I-90
CORRIDOR...THEN SHIFTING SLOWLY SEWRD LATE TODAY AND TONIGHT/. THE
HIGH RESOLUTION RAP AND 4KM NAM/ARW EACH SHOW THIS EVOLUTION LATER
THIS AFTERNOON AND OVERNIGHT. BY LATE THIS AFTERNOON THE NAM IMPLIES
SOME LES SNOWBANDS AFFECTING NW WARREN COUNTY.
HIGH TEMPS TODAY WILL VARY FROM THE U20S ACROSS THE MTNS TO THE MID
30S IN THE SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
THE LES AND COLD ARE THE TWO FORECAST ISSUES.
THE HIGH RESOLUTION MODELS IMPLY A SINGLE WEST-EAST SNOW BAND WHICH
WILL DRIFT INTO WARREN COUNTY AND LIKELY THE NW HALF MCKEAN COUNTY.
EXPANDED THE WINTER WEATHER ADVISORY TO MCKEAN COUNTY FOR LATE THIS
EVENING THROUGH 15Z MONDAY...AS THE MODERATELY STRONG MEAN BLYR FLOW
VEERS ABOUT 20-30 DEG...BACK TO A 270-280 DIRECTION. THIS TYPE OF
STEADY STATE WNW FLOW TYPICALLY SUPPORTS A LONGER DURATION/SINGLE
LES BAND THAT CAN PENETRATE FAIRLY FAR INLAND. A LIGHT COATING OF
SNOW IS POSSIBLE LATER TONIGHT AND MONDAY MORNING IN THE KIPT
AREA.
THE SNOW AMOUNTS IN WARREN USING A BLEND OF HIGH RESOLUTION MODELS
WAS IN THE 3-6 INCH RANGE...WHILE 2-4 INCHES IS LIKELY ACROSS THE NW
HALF OF MCKEAN COUNTY/ THE SREF WAS A BIT MORE ROBUST WITH THE POPS
AND QPF AREA WHICH WAS TRIMMED BACK MORE LIKE THE 4KM NAM.
THE NAM IMPLIES THE LES BAND COULD DRIFT OVER NORTHERN WARREN
COUNTY THIS EVENING AND THROUGH ABOUT 4 AM. THIS SIMULATION AND
THE RAP MAKE IT CLEAR BOTH FORECAST SYSTEMS THINK THERE SHOULD BE A
GOOD LES BAND IN SOUTHERN NY AND NW PA OVERNIGHT TONIGHT.
OUTSIDE THE LES AND UPSLOPE SNOW AREAS...IT WILL BE A VERY COLD
EVENING AND OVERNIGHT WITH SLOWLY ABATING WINDS.
COLD MONDAY WITH RESIDUAL SNOWS MAINLY CONFINED TO NORTHWESTERNMOST
AREAS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
THE GEFS-CMCEPS-SREF ALL SHOWS A CLIPPER PASSING TO OUR NORTH
TUESDAY. TIMING VARIES AND TRACK IS TO OUR NORTH THUS ANY
PRECIPITATION SHOULD BE LIGHT. TRIED TO SHOW THE POTENTIAL FOR
LIGHT SNOW TUESDAY. KEPT SNOW GENERALLY LOWER THAN 1 INCH AND
MAINLY CENTRAL AND NORTHERN AREAS.
THE NW FLOW WEAKENS AS A 500 HPA LOW DEVELOPS IN SW US LATER IN
THE WEEK. THIS ALLOWS FOR SOUTHWESTERLY FLOW AND A GRADUAL WARM UP
LIKELY THURSDAY INTO FRIDAY. MODELS IMPLY WARMEST DAY WOULD BE
FRIDAY. THIS WILL NOT LAST AS MODELS SHOWS DEEPENING TROUGH TO OUR
NORTH AND WEST AND A POOL OF ARCTIC AIR MOVING INTO THE LAKES
FRIDAY INTO SATURDAY. THUS SURFACE COLD FRONT SHOULD PUSH COLD AIR
BACK INTO OUR REGION SOMETIME NEXT WEEKEND.
BIAS CORRECT GEFS AND NAEFS SUGGEST TROUGH AND GENERALLY COLD
WEATHER SETTLE BACK IN THIS COMING WEEKEND AND INTO THE CHRISTMAS
WEEK.
AT THIS TIME NO BIG STORMS IN THE ENSEMBLES.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
DEEP WESTERLY FLOW AND EXTENSIVE BUT GENERALLY VERY WEAK UPWARD
MOTION IN THE LOW-MID LEVELS WILL MAINTAIN WIDESPREAD MVFR TO OCNL
IFR CIGS AND VSBYS IN LIGHT SNOW ACROSS THE CENTRAL AND NW
MTNS.
MAINLY VFR BKN CIGS WILL CONTINUE THROUGHOUT THE LOWER SUSQ VALLEY
THIS AFTERNOON. THE WIND WILL BE THE MAIN STORY FOR MOST CENTRAL AND
SUSQ REGION AIRFIELDS TODAY. SUSTAINED 12-17KTS WITH GUSTS INTO THE
MID/UPPER 20KT RANGE. THE ELEVATION AT JST WILL KEEP THEM ON THE
HIGHER-END OF WIND SPEEDS TODAY. LAKE EFFECT SHSN GO INTO HIGH GEAR
LATER THIS EVENING...AND BFD COULD BE IN FOR A LONG NIGHT OF IFR
SNOW AND CIGS.
FAST FLOW WILL BRING AN ALMOST NEVER-ENDING TRAIN OF WEAK NRN
STREAM IMPULSES TO MAKE SHSN FOR THE WRN TERMINALS FOR THE BULK OF
THE WEEK. THE STRONGEST CLIPPER WILL BE ON MON PM-TUE AM...WITH A
SEVERAL HOUR PERIOD OF MVFR TO OCNL IFR POSSIBLE IN STEADY LIGHT
SNOW AT MANY CENTRAL AND NRN PA TAF SITES. WARMER AIR TRIES TO
RETURN BY FRI.
OUTLOOK...
MON...MAINLY VFR WITH MVFR TO IFR IN SHSN AT BFD. MVFR ALSO LIKELY
AT KJST.
MON NITE-TUE...LGT SNOW/REDUCED VSBYS.
WED-THU...SHSN/REDUCED VSBYS POSS NW MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY FROM 9 PM THIS EVENING TO 10 AM EST
MONDAY FOR PAZ005.
LAKE EFFECT SNOW ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM
EST MONDAY FOR PAZ004.
&&
$$
SYNOPSIS...LAMBERT/GRUMM
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT/DANGELO
LONG TERM...GRUMM
AVIATION...LAMBERT/DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
747 AM EST SUN DEC 15 2013
.SYNOPSIS...
THE SURFACE LOW ALONG THE COAST IS NOW THE MAIN LOW TAKING THE
PRECIPITATION WITH IT. COLD AIR IS MOVING DOWN FROM THE NORTHWEST
AND WILL TRIGGER MOUNTAIN SNOW SHOWERS. A TROUGH WILL DOMINATE
OUR WEATHER THROUGH MOST OF THE NEXT 4 DAYS. A CLIPPER WILL PASS
TO OUR NORTH AND SHOULD PRODUCE LIGHT SNOW TUESDAY. HEIGHTS RISE
THURSDAY INTO EARLY SATURDAY AND THERE SHOULD BE A PERIOD OF
RELATIVELY WARM WEATHER LATER THIS WEEK. AFTER THAT...A
DEVELOPING TROUGH SHOULD PUSH COLD AIR BACK INTO PENNSYLVANIA
NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE SECONDARY SURFACE LOW WAS SOUTH OF LI AT 6 AM AND A COLD FRONT
WAS MOVING ACROSS WESTERN PENNSYLVANIA. THE PRECIPITATION OVER THE
REGION HAS OR WILL CHANGE TO ALL SNOW AS THE COLDER AIR FILTERS
INTO THE REGION. MOSTLY VERY LIGHT SNOW. BEHIND THE COLD FRONT
WINDS WILL BECOME GUSTY FROM THE WEST NORTHWEST LATER THIS MORNING
AND THIS AFTERNOON.
THE COLD AIR MOVING OVER THE LAKES BEHIND THIS FRONT WILL KICK OFF
LAKE EFFECT SNOW SHOWERS AND SNOW BANDS. THE RAP AND 4KM NAM EACH
SHOW THIS EVOLUTION LATER THIS AFTERNOON AND OVERNIGHT. BY LATE
THIS AFTERNOON THE NAM IMPLIES SOME LES SNOW AFFECTING WARREN
COUNTY.
SOME SNOW MAINLY IN MORNING OVER CENTRAL PA AS INDICATED ON
RADAR...VERY LIGHT WITH MINOR ACCUMULATION POSSIBLE IN SPOTS.
MOST LOCATIONS WILL BE WINDY AND COLD. THE MESOSCALE MODELS CLEAR
OUT SOUTHEASTERN PA THIS MORNING. AT THIS TIME ONLY INDICATIONS OF
CLEAR SKIES ARE IN THE DRY SLOT IN THE WV OVER CENTRAL AND
VIRGINIA. THE 11-3.9 MICRON DATA DOES NOT SHOW THIS YET. SUSPECT
WHEN WE SEE THIS VISIBLE IMAGES...CLOUD FORECASTS IN SOUTHEAST
WILL BE LOWERED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
THE LES AND COLD ARE THE TWO FORECAST ISSUES.
THE HIGH RESOLUTION MODELS IMPLY A SINGLE WEST-EAST SNOW BAND
WHICH AT TIMES COULD DRIFT INTO WARREN COUNTY AND PERHAPS MCKEAN
COUNTY. THE SNOW AMOUNTS IN WARREN USING A BLEND OF HIGH
RESOLUTION MODELS WAS IN THE 3-6 INCH RANGE. MUCH LOWER TO THE
SOUTH AND EAST. THE SREF WAS A BIT MORE ROBUST WITH THE POPS AND
QPF AREA WHICH WAS TRIMMED BACK MORE LIKE THE 4KM NAM.
THE NAM IMPLIES THE LES BAND COULD DRIFT OVER NORTHERN WARREN
COUNTY THIS EVENING AND THROUGH ABOUT 4 AM. THIS SIMULATION AND
THE RAP MAKE IT CLEAR BOTH FORECAST SYSTEMS THINK THERE SHOULD BE
A GOOD LES BAND IN SOUTHERN NY AND NW PA OVERNIGHT TONIGHT. THE
DETAILS WILL OF COURSE ELUDE US.
OUTSIDE THE LES AND UPSLOPE SNOW AREAS...WILL BE A VERY COLD
EVENING AND OVERNIGHT WITH SLOWLY ABATING WINDS.
COLD MONDAY WITH RESIDUAL SNOWS MAINLY CONFINED TO
NORTHWESTERNMOST AREAS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
THE GEFS-CMCEPS-SREF ALL SHOWS A CLIPPER PASSING TO OUR NORTH
TUESDAY. TIMING VARIES AND TRACK IS TO OUR NORTH THUS ANY
PRECIPITATION SHOULD BE LIGHT. TRIED TO SHOW THE POTENTIAL FOR
LIGHT SNOW TUESDAY. KEPT SNOW GENERALLY LOWER THAN 1 INCH AND
MAINLY CENTRAL AND NORTHERN AREAS.
THE NW FLOW WEAKENS AS A 500 HPA LOW DEVELOPS IN SW US LATER IN
THE WEEK. THIS ALLOWS FOR SOUTHWESTERLY FLOW AND A GRADUAL WARM UP
LIKELY THURSDAY INTO FRIDAY. MODELS IMPLY WARMEST DAY WOULD BE
FRIDAY. THIS WILL NOT LAST AS MODELS SHOWS DEEPENING TROUGH TO OUR
NORTH AND WEST AND A POOL OF ARCTIC AIR MOVING INTO THE LAKES
FRIDAY INTO SATURDAY. THUS SURFACE COLD FRONT SHOULD PUSH COLD AIR
BACK INTO OUR REGION SOMETIME NEXT WEEKEND.
BIAS CORRECT GEFS AND NAEFS SUGGEST TROUGH AND GENERALLY COLD
WEATHER SETTLE BACK IN THIS COMING WEEKEND AND INTO THE CHRISTMAS
WEEK.
AT THIS TIME NO BIG STORMS IN THE ENSEMBLES.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
THE AIR IS GETTING COLDER AS THE WIND HAS TURNED TO THE WNW OVER
THE WRN TERMINALS. THEY SHOULD TURN IN THE EAST VERY SHORTLY AS
THE SFC LOW DEEPENS EVEN MORE ON THE COAST. THE COOLING AIR HAS
TURNED ANY LINGERING PRECIP BACK TO SNOW...AND THE UPSLOPE FLOW
INTO THE WRN MTS IS FORCING LIGHT SNOW THERE. LOW CIGS
DOMINATE...BUT SOME RISE IN CLOUD BASES HAS ALREADY HAPPENED AT
MDT. THE CIGS SHOULD RISE AND CLOUDS BREAK UP SOME IN THE SE. THE
WIND WILL BE THE BIG STORY FOR MOST AIRFIELDS TODAY. SUSTAINED
12-17KTS WITH GUSTS INTO THE 30S IN THE WEST. THE GAP WIND AT AOO
AND ELEVATION AT JST WILL KEEP THEM ON THE HIGHER-END OF WIND
SPEEDS TODAY. LAKE EFFECT SHSN GO INTO HIGH GEAR LATER THIS
EVENING...AND BFD COULD BE IN FOR A LONG NIGHT OF IFR SNOW AND
CIGS.
FAST FLOW WILL BRING AN ALMOST NEVER-ENDING TRAIN OF WEAK NRN
STREAM IMPULSES TO MAKE SHSN FOR THE WRN TERMINALS FOR THE BULK OF
THE WEEK. THE STRONGEST CLIPPER WILL BE ON MON PM-TUE AM. WARM AIR
TRIES TO RETURN BY FRI.
OUTLOOK...
MON...MAINLY VFR WITH MVFR IN SHSN AT BFD.
MON NITE-TUE...LGT SNOW/REDUCED VSBYS.
WED-THU...SHSN/REDUCED VSBYS POSS NW MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM
EST MONDAY FOR PAZ004.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM/DANGELO
LONG TERM...GRUMM
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
640 AM EST SUN DEC 15 2013
.SYNOPSIS...
THE SURFACE LOW ALONG THE COAST IS NOW THE MAIN LOW TAKING THE
PRECIPITATION WITH IT. A COLD FRONT WILL MOVE OVER THE STATE
TODAY TRIGGERING MOUNTAIN SNOW SHOWERS. A TROUGH WILL DOMINATE
OUR WEATHER THROUGH MOST OF THE NEXT 4 DAYS. A CLIPPER WILL PASS
TO OUR NORTH AND SHOULD PRODUCE LIGHT SNOW TUESDAY. HEIGHTS RISE
THURSDAY INTO EARLY SATURDAY AND THERE SHOULD BE A PERIOD OF
RELATIVELY WARM WEATHER LATER THIS WEEK...DEVELOPING TROUGH SHOULD
PUSH COLD AIR BACK INTO PENNSYLVANIA NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE SECONDARY SURFACE LOW WAS SOUTH OF LI AT 6 AM AND A COLD FRONT
WAS MOVING ACROSS WESTERN PENNSYLVANIA. THE PRECIPITATION OVER THE
REGION HAS OR WILL CHANGE TO ALL SNOW AS THE COLDER AIR FILTERS
INTO THE REGION. MOSTLY VERY LIGHT SNOW. BEHIND THE COLD FRONT
WINDS WILL BECOME GUSTY FROM THE WEST NORTHWEST LATER THIS MORNING
AND THIS AFTERNOON.
THE COLD AIR MOVING OVER THE LAKES BEHIND THIS FRONT WILL KICK OFF
LAKE EFFECT SNOW SHOWERS AND SNOW BANDS. THE RAP AND 4KM NAM EACH
SHOW THIS EVOLUTION LATER THIS AFTERNOON AND OVERNIGHT. BY LATE
THIS AFTERNOON THE NAM IMPLIES SOME LES SNOW AFFECTING WARREN
COUNTY.
SOME SNOW MAINLY IN MORNING OVER CENTRAL PA AS INDICATED ON
RADAR...VERY LIGHT WITH MINOR ACCUMULATION POSSIBLE IN SPOTS.
MOST LOCATIONS WILL BE WINDY AND COLD. THE MESOSCALE MODELS CLEAR
OUT SOUTHEASTERN PA THIS MORNING. AT THIS TIME ONLY INDICATIONS OF
CLEAR SKIES ARE IN THE DRY SLOT IN THE WV OVER CENTRAL AND
VIRGINIA. THE 11-3.9 MICRON DATA DOES NOT SHOW THIS YET. SUSPECT
WHEN WE SEE THIS VISIBLE IMAGES...CLOUD FORECASTS IN SOUTHEAST
WILL BE LOWERED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
THE LES AND COLD ARE THE TWO FORECAST ISSUES.
THE HIGH RESOLUTION MODELS IMPLY A SINGLE WEST-EAST SNOW BAND
WHICH AT TIMES COULD DRIFT INTO WARREN COUNTY AND PERHAPS MCKEAN
COUNTY. THE SNOW AMOUNTS IN WARREN USING A BLEND OF HIGH
RESOLUTION MODELS WAS IN THE 3-6 INCH RANGE. MUCH LOWER TO THE
SOUTH AND EAST. THE SREF WAS A BIT MORE ROBUST WITH THE POPS AND
QPF AREA WHICH WAS TRIMMED BACK MORE LIKE THE 4KM NAM.
THE NAM IMPLIES THE LES BAND COULD DRIFT OVER NORTHERN WARREN
COUNTY THIS EVENING AND THROUGH ABOUT 4 AM. THIS SIMULATION AND
THE RAP MAKE IT CLEAR BOTH FORECAST SYSTEMS THINK THERE SHOULD BE
A GOOD LES BAND IN SOUTHERN NY AND NW PA OVERNIGHT TONIGHT. THE
DETAILS WILL OF COURSE ELUDE US.
OUTSIDE THE LES AND UPSLOPE SNOW AREAS...WILL BE A VERY COLD
EVENING AND OVERNIGHT WITH SLOWLY ABATING WINDS.
COLD MONDAY WITH RESIDUAL SNOWS MAINLY CONFINED TO
NORTHWESTERNMOST AREAS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
THE GEFS-CMCEPS-SREF ALL SHOWS A CLIPPER PASSING TO OUR NORTH
TUESDAY. TIMING VARIES AND TRACK IS TO OUR NORTH THUS ANY
PRECIPITATION SHOULD BE LIGHT. TRIED TO SHOW THE POTENTIAL FOR
LIGHT SNOW TUESDAY. KEPT SNOW GENERALLY LOWER THAN 1 INCH AND
MAINLY CENTRAL AND NORTHERN AREAS.
THE NW FLOW WEAKENS AS A 500 HPA LOW DEVELOPS IN SW US LATER IN
THE WEEK. THIS ALLOWS FOR SOUTHWESTERLY FLOW AND A GRADUAL WARM UP
LIKELY THURSDAY INTO FRIDAY. MODELS IMPLY WARMEST DAY WOULD BE
FRIDAY. THIS WILL NOT LAST AS MODELS SHOWS DEEPENING TROUGH TO OUR
NORTH AND WEST AND A POOL OF ARCTIC AIR MOVING INTO THE LAKES
FRIDAY INTO SATURDAY. THUS SURFACE COLD FRONT SHOULD PUSH COLD AIR
BACK INTO OUR REGION SOMETIME NEXT WEEKEND.
BIAS CORRECT GEFS AND NAEFS SUGGEST TROUGH AND GENERALLY COLD
WEATHER SETTLE BACK IN THIS COMING WEEKEND AND INTO THE CHRISTMAS
WEEK.
AT THIS TIME NO BIG STORMS IN THE ENSEMBLES.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
FREEZING DRIZZLE COVERS MOST OF THE AREA AS THE HIGH SEEDER CLOUDS
HAVE PRETTY MUCH MOVED AWAY. BUT THE PRECIP IS TURNING TO SNOW
AGAIN AS THE LOWER CLOUDS TO THE WEST OF THE PRIMARY LOW LOCATED
OVER KBFD MOVES TOWARD NY STATE AND THE COLDEST AIR WRAPS BACK
IN FROM THE WEST. LOW CIGS DOMINATE...BUT SOME RISE IN CLOUD BASES
IS STARTING IN THE EAST...AND THE SERN TERMINALS MAY IMPROVE TO A
HIGH-END MVFR OR EVEN VFR AROUND SUNRISE.
SFC LOWS BATTLING IT OUT WITH MOST OF CENTRAL PA IN A BIT OF A COL
AT THE MOMENT...BUT THE STRONGER COASTAL LOW SHOULD TAKE OVER BY
SUNRISE. EXPECT WESTERN PRECIPITATION TO CONTINUE TO LIGHTEN
OVERNIGHT AS THE WESTERN LOW FILLS. EXPECT WIND SHIFT TO THE WEST
SHORTLY AT ALL SITES. THEN WINDS SHIFT NORTHWEST AS THE COASTAL
LOW STRENGTHENS AND PULLS NORTH.
WNWRLY FLOW WITH IT/S TYPICAL POST-FRONTAL UPSLOPE SHSN AND LAKE
ENHANCEMENT WILL PROVIDE EQUAL AMOUNTS OF MVFR AND IFR THROUGH THE
DAYLIGHT HOURS. LOTS OF MECHANICAL TURBULENCE EXPECTED AS THE WIND
WILL GET STRONGER AS THE MORNING CONTINUES. SUSTAINED 12-15KTS
WITH GUSTS INTO THE 30S ARE EXPECTED AT JST/BFD THIS AFTN. ONLY
SLIGHTLY LOWER SPEEDS ARE IN STORE FOR THE OTHER TERMINALS. THE
GAP WIND AT AOO AND DOWNSLOPE AT MDT/LNS WILL KEEP THEM ON THE
HIGHER-END OF WIND SPEEDS TODAY.
FAST FLOW BRINGS AN ALMOST NEVER-ENDING TRAIN OF WEAK NRN STREAM
IMPULSES TO MAKE SHSN FOR THE WRN TERMINALS. THE STRONGEST CLIPPER
WILL BE ON TUE AM. WARM AIR TRIES TO RETURN BY FRI.
OUTLOOK...
MON...MAINLY VFR WITH MVFR IN SHSN AT BFD.
MON NITE-TUE...LGT SNOW/REDUCED VSBYS.
WED-THU...SHSN/REDUCED VSBYS POSS NW MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM
EST MONDAY FOR PAZ004.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM/DANGELO
LONG TERM...GRUMM
AVIATION...JUNG/DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
257 AM EST SUN DEC 15 2013
.SYNOPSIS...
A COMPLEX LOW PRESSURE SYSTEM WITH ENERGY TRANSFERRING FROM THE
UPPER OHIO VALLEY TO THE MID-ATLANTIC COAST WILL CONTINUE TO BRING
WINTRY PRECIPITATION TO THE REGION THROUGH TONIGHT. WINTER STORM
WARNINGS REMAIN IN EFFECT FOR ALL OF CENTRAL PENNSYLVANIA UNTIL 4
AM SUNDAY. A MEAN LONG WAVE TROUGH IS EXPECTED TO PERSIST ACROSS
THE GREAT LAKES AND NORTHEAST THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 9 AM THIS MORNING/...
THE HEAVIER PRECIPITATION IS NOW TO OUR EAST. BUT AN ELEVATED WARM
LAYER NOW COVERS MOST OF THE EASTERN THIRD OF OUR AREA TO INCLUDE
SULLIVAN COUNTY AND OUR EXTREME NORTHEAST. THUS FREEZING RAIN AND
ICE PELLETS ARE FALLING IN THE NORTHERN AREAS. THE LACK OF HIGH
CLOUDS IS MAKING THE TRANSITION TO FREEZING DRIZZLE IN SOME
CENTRAL AND SOUTHEASTERN AREAS.
COLDER DRIER AIR TO THE WEST IS ALREADY WORKING IN AND SHOULD TURN
ANY PRECIPITATION BACK TO LIGHT SNOW OR SNOW SHOWERS. THE RUC
APPEARS TO THINK THE 0C ISOTHERM WILL CLEAR STATE COLLEGE BETWEEN
1-2 AM AND LANCASTER COUNTY BETWEEN 7 AND 8 AM.
RADAR SHOWS MOST OF THE STEADIER PRECIPITATION IS NOW NORTH OF
STATE COLLEGE AND LIFTING TO THE NORTH AND EAST. THIS IMPLIES THE
LACK OF SEEDER FEEDER EFFECT THAT MOST AREAS WILL HAVE FREEZING
DRIZZLE UNTIL THE COLDER AIR MOVE INTO THE REGION OVER THE NEXT 6 HOURS.
&&
.SHORT TERM /9 AM THIS MORNING THROUGH 6 PM MONDAY/...
CONDITIONS SHOULD IMPROVE DURING THE DAY SUNDAY. WITH MAINLY SNOW
SHOWERS AND FLURRIES OVER THE REGION. THE GRADIENT PICKS UP AND IT
WILL SHOULD BE SOME GUSTY WINDS BY LATER MORNING AND INTO THE AFTERNOON.
THE 13KM RAP AND 4KM NAM SHOW A GOOD LAKE EFFECT SNOW (LES) BAND
GETTING WOUND UP...MOST OF THE SIMULATE INTENSE REFLECTIVITY STAYS
IN NEW YORK BUT IT COULD DRIFT SOUTH SO WE KEPT SNOW SHOWERS UP IN
NW PA THROUGH SUNDAY NIGHT. THERE WILL LIKELY BE SOME UPSLOPE SNOW
SHOWERS IN THE SOUTHWESTERN MOUNTAINS FROM SOUTHERN CLEARFIELD TO
SOMERSET COUNTIES.
MOST ACCUMULATING SNOWS SUNDAY WILL BE CONFINED TO LES AREAS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
IN THE WAKE OF THE EARLY WEEKEND STORM...A MEAN UPPER LEVEL TROF
WILL REMAIN OVER THE EASTERN THIRD OF COUNTRY. SEVERAL SHORTWAVES
ARE FORECAST TO MOVE THROUGH THE FAST WEST NORTHWESTERLY FLOW. THE
FIRST IS FORECAST TO MOVE ACROSS THE REGION SUNDAY AFTERNOON
BRINGING ANOTHER SHOT OF SNOW SHOWERS MAINLY TO THE NORTHERN TIER.
ANOTHER WILL BRING A FRONT ON TUESDAY...WITH LIMITED MOISTURE.
HAVE INCREASED POPS ACCORDINGLY...HOWEVER DUE TO THE LIMITED
MOISTURE HAVE ONLY LIGHT ACCUMULATIONS. TEMPERATURES THROUGH THE
MIDDLE OF THE WEEK WILL REMAIN COLD...AS 850MB TEMPS -10C OR
BELOW. SO LOOK FOR DAYTIME HIGHS TO BE BELOW NORMAL THROUGH MUCH
OF THE PERIOD. GUIDANCE SUGGESTS THAT BY LATE IN THE WEEK ENERGY
WILL DIVE INTO THE ROCKIES IN TURN PUMPING UP HEIGHTS OVER THE
EAST. BRINGING A POSSIBLE WARM UP TO THE REGION LATE NEXT WEEK.
THIS SHOULD ALLOW FOR HIGHS FOR FRIDAY IN THE 40S ACROSS PA.
MOISTURE OUT AHEAD OF THE FRONT COULD ALLOW FOR RAIN
SHOWERS...WITH COLD AIR BEHIND...SO MIXED PRECIPITATION AT AND
BEHIND THE FRONT REMAINS A POSSIBILITY. THE MODELS VARY IN TIMING
BUT ALL AGREE THAT NEXT WEEKEND SHOULD SEE A DEEP TROUGH MOVE
THROUGH THE MID WEST AND INTO THE EAST COAST. THIS WILL END THE
BRIEF WARM UP AND SEE THE RETURN OF COLD AIR.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
FREEZING DRIZZLE COVERS MOST OF THE AREA AS THE HIGH SEEDER CLOUDS
HAVE PRETTY MUCH MOVED AWAY. BUT THE PRECIP IS TURNING TO SNOW
AGAIN AS THE LOWER CLOUDS TO THE WEST OF THE PRIMARY LOW LOCATED
OVER KBFD MOVES TOWARD NY STATE AND THE COLDEST AIR WRAPS BACK
IN FROM THE WEST. LOW CIGS DOMINATE...BUT SOME RISE IN CLOUD BASES
IS STARTING IN THE EAST...AND THE SERN TERMINALS MAY IMPROVE TO A
HIGH-END MVFR OR EVEN VFR AROUND SUNRISE.
SFC LOWS BATTLING IT OUT WITH MOST OF CENTRAL PA IN A BIT OF A COL
AT THE MOMENT...BUT THE STRONGER COASTAL LOW SHOULD TAKE OVER BY
SUNRISE. EXPECT WESTERN PRECIPITATION TO CONTINUE TO LIGHTEN
OVERNIGHT AS THE WESTERN LOW FILLS. EXPECT WIND SHIFT TO THE WEST
SHORTLY AT ALL SITES. THEN WINDS SHIFT NORTHWEST AS THE COASTAL
LOW STRENGTHENS AND PULLS NORTH.
WNWRLY FLOW WITH IT/S TYPICAL POST-FRONTAL UPSLOPE SHSN AND LAKE
ENHANCEMENT WILL PROVIDE EQUAL AMOUNTS OF MVFR AND IFR THROUGH THE
DAYLIGHT HOURS. LOTS OF MECHANICAL TURBULENCE EXPECTED AS THE WIND
WILL GET STRONGER AS THE MORNING CONTINUES. SUSTAINED 12-15KTS
WITH GUSTS INTO THE 30S ARE EXPECTED AT JST/BFD THIS AFTN. ONLY
SLIGHTLY LOWER SPEEDS ARE IN STORE FOR THE OTHER TERMINALS. THE
GAP WIND AT AOO AND DOWNSLOPE AT MDT/LNS WILL KEEP THEM ON THE
HIGHER-END OF WIND SPEEDS TODAY.
FAST FLOW BRINGS AN ALMOST NEVER-ENDING TRAIN OF WEAK NRN STREAM
IMPULSES TO MAKE SHSN FOR THE WRN TERMINALS. THE STRONGEST CLIPPER
WILL BE ON TUE AM. WARM AIR TRIES TO RETURN BY FRI.
OUTLOOK...
MON...MAINLY VFR WITH MVFR IN SHSN AT BFD.
MON NITE-TUE...LGT SNOW/REDUCED VSBYS.
WED-THU...SHSN/REDUCED VSBYS POSS NW MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 4 AM EST EARLY THIS MORNING FOR
PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-
049>053-056>059-063>066.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...GRUMM/STEINBUGL
SHORT TERM...GRUMM/DANGELO/LAMBERT
LONG TERM...CERU/GARTNER
AVIATION...JUNG/DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1228 AM EST SUN DEC 15 2013
.SYNOPSIS...
A COMPLEX LOW PRESSURE SYSTEM WITH ENERGY TRANSFERRING FROM THE
UPPER OHIO VALLEY TO THE MID-ATLANTIC COAST WILL CONTINUE TO BRING
WINTRY PRECIPITATION TO THE REGION THROUGH TONIGHT. WINTER STORM
WARNINGS REMAIN IN EFFECT FOR ALL OF CENTRAL PENNSYLVANIA UNTIL 4
AM SUNDAY. A MEAN LONGWAVE TROUGH IS EXPECTED TO PERSIST ACROSS
THE GREAT LAKES AND NORTHEAST THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 9 AM THIS MORNING/...
THE HEAVIER PRECIPITATION IS NOW TO OUR EAST. BUT AN ELEVATED WARM
LAYER NOW COVERS MOST OF THE EASTERN THIRD OF OUR AREA TO INCLUDE
SULLIVAN COUNTY AND OUR EXTREME NORTHEAST. THUS FREEZING RAIN AND
ICE PELLETS ARE FALLING IN THE NORTHERN AREAS. THE LACK OF HIGH
CLOUDS IS MAKING THE TRANSITION TO FREEZING DRIZZLE IN SOME
CENTRAL AND SOUTHEASTERN AREAS.
COLDER DRIER AIR TO THE WEST IS ALREADY WORKING IN AND SHOULD TURN
ANY PRECIPITATION BACK TO LIGHT SNOW OR SNOW SHOWERS. THE RUC
APPEARS TO THINK THE 0C ISOTHERM WILL CLEAR STATE COLLEGE BETWEEN
1-2 AM AND LANCASTER COUNTY BETWEEN 7 AND 8 AM.
RADAR SHOWS MOST OF THE STEADIER PRECIPITATION IS NOW NORTH OF
STATE COLLEGE AND LIFTING TO THE NORTH AND EAST. THIS IMPLIES THE
LACK OF SEEDER FEEDER EFFECT THAT MOST AREAS WILL HAVE FREEZING
DRIZZLE UNTIL THE COLDER AIR MOVE INTO THE REGION OVER THE NEXT 6 HOURS.
&&
.SHORT TERM /9 AM THIS MORNING THROUGH 6 PM MONDAY/...
CONDITIONS SHOULD IMPROVE DURING THE DAY SUNDAY. WITH MAINLY SNOW
SHOWERS AND FLURRIES OVER THE REGION. THE GRADIENT PICKS UP AND IT
WILL SHOULD BE SOME GUSTY WINDS BY LATER MORNING AND INTO THE AFTERNOON.
THE 13KM RAP AND 4KM NAM SHOW A GOOD LAKE EFFECT SNOW (LES) BAND
GETTING WOUND UP...MOST OF THE SIMULATE INTENSE REFLECTIVITY STAYS
IN NEW YORK BUT IT COULD DRIFT SOUTH SO WE KEPT SNOW SHOWERS UP IN
NW PA THROUGH SUNDAY NIGHT. THERE WILL LIKELY BE SOME UPSLOPE SNOW
SHOWERS IN THE SOUTHWESTERN MOUNTAINS FROM SOUTHERN CLEARFIELD TO
SOMERSET COUNTIES.
MOST ACCUMULATING SNOWS SUNDAY WILL BE CONFINED TO LES AREAS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
IN THE WAKE OF THE EARLY WEEKEND STORM...A MEAN UPPER LEVEL TROF
WILL REMAIN OVER THE EASTERN THIRD OF COUNTRY. SEVERAL SHORTWAVES
ARE FORECAST TO MOVE THROUGH THE FAST WEST NORTHWESTERLY FLOW. THE
FIRST IS FORECAST TO MOVE ACROSS THE REGION SUNDAY AFTERNOON
BRINGING ANOTHER SHOT OF SNOW SHOWERS MAINLY TO THE NORTHERN TIER.
ANOTHER WILL BRING A FRONT ON TUESDAY...WITH LIMITED MOISTURE.
HAVE INCREASED POPS ACCORDINGLY...HOWEVER DUE TO THE LIMITED
MOISTURE HAVE ONLY LIGHT ACCUMULATIONS. TEMPERATURES THROUGH THE
MIDDLE OF THE WEEK WILL REMAIN COLD...AS 850MB TEMPS -10C OR
BELOW. SO LOOK FOR DAYTIME HIGHS TO BE BELOW NORMAL THROUGH MUCH
OF THE PERIOD. GUIDANCE SUGGESTS THAT BY LATE IN THE WEEK ENERGY
WILL DIVE INTO THE ROCKIES IN TURN PUMPING UP HEIGHTS OVER THE
EAST. BRINGING A POSSIBLE WARM UP TO THE REGION LATE NEXT WEEK.
THIS SHOULD ALLOW FOR HIGHS FOR FRIDAY IN THE 40S ACROSS PA.
MOISTURE OUT AHEAD OF THE FRONT COULD ALLOW FOR RAIN
SHOWERS...WITH COLD AIR BEHIND...SO MIXED PRECIPITATION AT AND
BEHIND THE FRONT REMAINS A POSSIBILITY. THE MODELS VARY IN TIMING
BUT ALL AGREE THAT NEXT WEEKEND SHOULD SEE A DEEP TROUGH MOVE
THROUGH THE MID WEST AND INTO THE EAST COAST. THIS WILL END THE
BRIEF WARM UP AND SEE THE RETURN OF COLD AIR.
&&
.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
SIGNIFICANT PRECIPITATION NOW GENERALLY ALONG AND NORTH OF I-80.
FREEZING RAIN AND SLEET LINE HAS MADE IT INTO CENTRAL AREAS...WITH
KAOO...KUNV...KMDT ALL REPORTING SOME MIX OF FZRA AND PL. NORTH
OF THIS LINE...STILL LIGHT TO OCCASIONAL MODERATE SNOW FALLING.
IN THE FAR SOUTHEAST...LIGHT TO MODERATE FREEZING RAIN FALLING. IT
IS CLEAR THAT THE COASTAL LOW IS TAKING OVER IN THIS AREA...AND
DRIVING THE PRECIPITATION. SURFACE WINDS HAVE NOW BACKED TO THE
NORTHEAST AT KMDT AND KLNS...ALSO INDICATING THAT REGION IS FULLY
UNDER THE INFLUENCE OF THE DEVELOPING COASTAL LOW.
EXPECT WESTERN PRECIPITATION TO CONTINUE TO LIGHTEN OVERNIGHT AS
THE WESTERN LOW FILLS. EXPECT WIND SHIFT TO THE WEST AROUND 06Z IN
KJST...07-09Z IN KAOO AND KUNV. THEN WINDS SHIFT NORTHWEST AS THE
COASTAL LOW STRENGTHENS AND PULLS NORTH.
EVEN WITH PRECIPITATION ENDING...IFR CIGS WILL LINGER
OVERNIGHT...WITH SOME IMPROVEMENT TOWARDS 12Z IN THE FAVORED
DOWNSLOPING AREAS IN CENTRAL AND SOUTHEAST PA.
OUTLOOK...
SUN...GUSTY WNW WINDS. AM LOW CIGS POSS W MTNS. PM SHSN/REDUCED
VSBYS POSS W MTNS.
MON...LGT SNOW/REDUCED VSBYS POSS MON NITE NW MTNS.
TUE...AM LOW CIGS/LGT SNOW POSS NW MTNS.
WED...SHSN/REDUCED VSBYS POSS NW MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 4 AM EST EARLY THIS MORNING FOR
PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-
049>053-056>059-063>066.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...GRUMM/STEINBUGL
SHORT TERM...GRUMM/DANGELO/LAMBERT
LONG TERM...CERU/GARTNER
AVIATION...JUNG
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1144 AM CST SUN DEC 15 2013
.UPDATE...
BAND OF ISENTROPIC/WAA DRIVEN SNOW CONTINUES TO DEVELOP OVER THE
FORECAST AREA AS OF 10AM. RIGHT NOW THE MOST PERSISTENT SNOW IS
OCCURRING FROM JUST EAST OF MOBRIDGE AND FAULKTON...TO ABERDEEN
AND REDFIELD. VSBYS IN THIS BAND WILL LIKELY DROP TO BELOW ONE
MILE AT TIMES. DECENT AGREEMENT AMONGST THE HI-RES MODELS ON SHIFTING
THIS NW/SE BAND OF SNOW TO THE EAST THE REMAINDER OF THE
AFTERNOON. SNOW ACCUMULATION THROUGH EVENING IS STILL EXPECTED TO
BE AROUND 1 INCH ACROSS N-CENTRAL AND NERN SD AND WRN MN...WITH ISOLATED
AREAS PICKING UP AS MUCH AS 2 INCHES.
BIG CONTRAST IN TEMPERATURES ACROSS SOUTH DAKOTA. RAPID CITY AREA IS
CURRENTLY BASKING IN THE 40S...WITH AREAS IN THE EAST REMAINING
NEAR ZERO. WILL BE CHALLENGING TO DETERMINE JUST HOW FAR EAST THIS
WARMER AIRMASS WILL BE ABLE TO ADVECT TODAY. LATEST GUIDANCE HAS
IT PUSHING AS FAR EAST AS STANLEY/JONES/DEWEY COUNTIES BY
EVENING...WHICH SEEMS REASONABLE.
BIGGER PUSH OF WARM AIR WILL OCCUR TONIGHT...MORE ON THAT THIS
AFTERNOON. UPDATES ALREADY OUT.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH TUESDAY
LOCATION OF SHARP WARM FRONT A NO-BRAINER EARLY THIS MORNING AS IT
IS EASILY NOTICEABLE ON SFC OBS. FAITH AND PHILIP ARE 36 AND 37
DEGREES RESPECTIVELY WITH A NORTHWEST WIND...WHILE MOBRIDGE AND
PIERRE ARE STILL IN THE LOWER TEENS WITH A SOUTHEAST WIND. THIS
FRONT CONTINUES NORTHWEST INTO SOUTHWEST NORTH DAKOTA. AS
ADVERTISED...LIGHT SNOW IS ONGOING AHEAD OF THE FRONT WITHIN ZONE
OF LIFT AND FORCING...MAINLY FROM NORTHWEST NORTH DAKOTA AND JUST
NOW INTO NORTH CENTRAL SOUTH DAKOTA. MODELS SEEM TO BE A FEW HOURS
QUICKER WITH THE ONSET OF LIGHT SNOW SO HAVE MADE THE APPROPRIATE
ADJUSTMENTS IN WX/POP GRIDS. MODELS STILL IN RATHER GOOD AGREEMENT
AS WELL...BRINGING A SWATH OF LIGHT SNOW RIGHT DOWN THROUGH THE
NORTHEAST QUARTER OF SOUTH DAKOTA INTO WEST CENTRAL MINNESOTA. A
BIT HARDER TO NAIL DOWN WITH MORE SPECIFICITY THE ACTUAL AREA OF
SLIGHTLY ENHANCED SNOWFALL...BUT INDICATIONS IN MODELS ARE THAT IT
ACTUALLY MIGHT BE RIGHT DOWN THROUGH ABERDEEN TO NEAR
WATERTOWN...SO HAVE SLIGHTLY HIGHER SNOWFALL TOTALS IN THIS
AREA...AROUND AN INCH OR SLIGHTLY HIGHER. SOME OF THE HI RES
MODELS SHOWING THE SNOW MIGHT BE ENDING A BIT QUICKER AS
WELL...DUE TO THE EARLIER ONSET. LATEST RUN OF THE HRRR ACTUALLY
SHOWING MOST SNOW OUT OF THE AREA BY 20Z OR 21Z. A TREND TO WATCH
THROUGH THE DAY.
AFTER THE BULK OF THE SNOWFALL ENDS BY LATE AFTERNOON...ATTENTION
THEN TURNS TO THE EASTWARD PROGRESSION OF THE WARM FRONT AND
DETERMINING JUST HOW WARM TEMPS WILL GET ON MONDAY. MODELS DO NOT
SHOW MUCH MOVEMENT OF THE FRONT AT ALL TODAY...STILL HUNG UP NEAR
THE MISSOURI RIVER BY 00Z THIS EVENING. BUT OVERNIGHT...THERE IS
FINALLY A PUSH TO THE EAST WHICH SHOULD TAKE IT THROUGH MOST IF
NOT ALL THE CWA BY 12Z MONDAY MORNING. THUS...WILL SEE SLOWLY
RISING TEMPS THROUGH THE NIGHT FOR EASTERN AREAS AS THIS FRONT
MOVES THROUGH. DID NOT STRAY MUCH AT ALL FROM PREVIOUS FORECAST
FOR HIGHS ON MONDAY...THEY STILL SEEM IN GOOD SHAPE AT THIS TIME.
MOST AREAS WILL RISE INTO THE 30S AND LOW 40S...EVEN WITH THE SNOW
COVER. WARMEST TEMPS WILL BE OVER THE SOUTHWEST CWA. TUESDAY
SHAPING UP TO NOT BE THAT BAD OF A DAY EITHER. TEMPS ALOFT COOL
SLIGHTLY AND MIXING WILL BE LESS...BUT SHOULD STILL MANAGE UPPER
20S TO MID 30S FOR MOST AREAS.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
NEARLY ZONAL UPPER LEVEL FLOW ON WEDNESDAY WITH NEAR NORMAL SFC
TEMPS GIVES WAY TO AN ARCTIC FRONT INTRUDING FROM THE NORTHWEST
AND A SFC LOW MOVING THROUGH THE CENTRAL PLAINS ON THURSDAY. THE
GFS IS A LITTLE SLOWER TO PROGRESS THE PRECIP SOUTH WITH THE FRONT
AND HANGS IT AROUND A LITTLE LONGER. WITH SFC HIGH PRESSURE
SETTLING OVER THE REGION ON FRIDAY BELIEVE THE ECMWF AND THE
ALLBLEND ARE A BETTER BET WITH ALL PRECIP EXITING THU NIGHT.
SIGNIFICANTLY COOLER TEMPS AND DRIER CONDITIONS WILL THEN PERSIST
THROUGH THE WEEKEND AS NORTHWEST FLOW ALOFT TAKES HOLD ONCE AGAIN.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
A WARM FRONT IS CURRENTLY TRACKING INTO WESTERN SOUTH DAKOTA. A
BAND OF LIGHT SNOWFALL HAS DEVELOPED AHEAD OF THE FRONT...WITH
MAINLY MVFR CONDITIONS...ALTHOUGH VFR VSBYS AND CIGS CAN BE
EXPECTED UNDER THE HEAVIEST SNOWFALL. THIS HEAVIEST BAND WILL
MAINLY AFFECT KABR THIS AFTERNOON...BUT COULD SHIFT AS FAR EAST AS
KATY. THE AREA OF SNOWFALL WILL GRADUALLY SLIDE SOUTHEAST AND
DISSIPATE LATER THIS AFTERNOON AND EVENING. WINDS WILL SHIFT TO
THE WEST BEHIND THE FRONT.
EQUIPMENT FAILURE AT THE KATY ASOS HAS CAUSED MISSING
OBSERVATIONS. MAINTENANCE IS BEING PERFORMED...BUT UNTIL THE
OBSERVATIONS RETURN...THE KATY TAF WILL BE NIL.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...FOWLE
SHORT TERM...TMT
LONG TERM...WISE
AVIATION...SERR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
1036 AM CST SUN DEC 15 2013
.UPDATE...
BAND OF ISENTROPIC/WAA DRIVEN LIGHT SNOW CONTINUES TO DEVELOP
OVER THE FORECAST AREA AS OF 10AM. RIGHT NOW THE MOST PERSISTENT
SNOW IS OCCURRING FROM JUST EAST OF MOBRIDGE AND FAULKTON...TO
ABERDEEN AND REDFIELD. VSBYS IN THIS BAND WILL LIKELY DROP TO
BELOW ONE MILE AT TIMES. DECENT AGREEMENT AMONGST THE HI-RES
MODELS ON SHIFTING THIS NW/SE BAND OF SNOW TO THE EAST THE
REMAINDER OF THE AFTERNOON. SNOW ACCUMULATION THROUGH EVENING IS
STILL EXPECTED TO BE AROUND 1 INCH ACROSS N-CENTRAL AND NERN SD
AND WRN MN...WITH ISOLATED AREAS PICKING UP AS MUCH AS 2 INCHES.
BIG CONTRAST IN TEMPERATURES ACROSS SOUTH DAKOTA. RAPID CITY AREA IS
CURRENTLY BASKING IN THE 40S...WITH AREAS IN THE EAST REMAINING
NEAR ZERO. WILL BE CHALLENGING TO DETERMINE JUST HOW FAR EAST THIS
WARMER AIRMASS WILL BE ABLE TO ADVECT TODAY. LATEST GUIDANCE HAS
IT PUSHING AS FAR EAST AS STANLEY/JONES/DEWEY COUNTIES BY
EVENING...WHICH SEEMS REASONABLE.
BIGGER PUSH OF WARM AIR WILL OCCUR TONIGHT...MORE ON THAT THIS
AFTERNOON. UPDATES ALREADY OUT.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH TUESDAY
LOCATION OF SHARP WARM FRONT A NO-BRAINER EARLY THIS MORNING AS IT
IS EASILY NOTICEABLE ON SFC OBS. FAITH AND PHILIP ARE 36 AND 37
DEGREES RESPECTIVELY WITH A NORTHWEST WIND...WHILE MOBRIDGE AND
PIERRE ARE STILL IN THE LOWER TEENS WITH A SOUTHEAST WIND. THIS
FRONT CONTINUES NORTHWEST INTO SOUTHWEST NORTH DAKOTA. AS
ADVERTISED...LIGHT SNOW IS ONGOING AHEAD OF THE FRONT WITHIN ZONE
OF LIFT AND FORCING...MAINLY FROM NORTHWEST NORTH DAKOTA AND JUST
NOW INTO NORTH CENTRAL SOUTH DAKOTA. MODELS SEEM TO BE A FEW HOURS
QUICKER WITH THE ONSET OF LIGHT SNOW SO HAVE MADE THE APPROPRIATE
ADJUSTMENTS IN WX/POP GRIDS. MODELS STILL IN RATHER GOOD AGREEMENT
AS WELL...BRINGING A SWATH OF LIGHT SNOW RIGHT DOWN THROUGH THE
NORTHEAST QUARTER OF SOUTH DAKOTA INTO WEST CENTRAL MINNESOTA. A
BIT HARDER TO NAIL DOWN WITH MORE SPECIFICITY THE ACTUAL AREA OF
SLIGHTLY ENHANCED SNOWFALL...BUT INDICATIONS IN MODELS ARE THAT IT
ACTUALLY MIGHT BE RIGHT DOWN THROUGH ABERDEEN TO NEAR
WATERTOWN...SO HAVE SLIGHTLY HIGHER SNOWFALL TOTALS IN THIS
AREA...AROUND AN INCH OR SLIGHTLY HIGHER. SOME OF THE HI RES
MODELS SHOWING THE SNOW MIGHT BE ENDING A BIT QUICKER AS
WELL...DUE TO THE EARLIER ONSET. LATEST RUN OF THE HRRR ACTUALLY
SHOWING MOST SNOW OUT OF THE AREA BY 20Z OR 21Z. A TREND TO WATCH
THROUGH THE DAY.
AFTER THE BULK OF THE SNOWFALL ENDS BY LATE AFTERNOON...ATTENTION
THEN TURNS TO THE EASTWARD PROGRESSION OF THE WARM FRONT AND
DETERMINING JUST HOW WARM TEMPS WILL GET ON MONDAY. MODELS DO NOT
SHOW MUCH MOVEMENT OF THE FRONT AT ALL TODAY...STILL HUNG UP NEAR
THE MISSOURI RIVER BY 00Z THIS EVENING. BUT OVERNIGHT...THERE IS
FINALLY A PUSH TO THE EAST WHICH SHOULD TAKE IT THROUGH MOST IF
NOT ALL THE CWA BY 12Z MONDAY MORNING. THUS...WILL SEE SLOWLY
RISING TEMPS THROUGH THE NIGHT FOR EASTERN AREAS AS THIS FRONT
MOVES THROUGH. DID NOT STRAY MUCH AT ALL FROM PREVIOUS FORECAST
FOR HIGHS ON MONDAY...THEY STILL SEEM IN GOOD SHAPE AT THIS TIME.
MOST AREAS WILL RISE INTO THE 30S AND LOW 40S...EVEN WITH THE SNOW
COVER. WARMEST TEMPS WILL BE OVER THE SOUTHWEST CWA. TUESDAY
SHAPING UP TO NOT BE THAT BAD OF A DAY EITHER. TEMPS ALOFT COOL
SLIGHTLY AND MIXING WILL BE LESS...BUT SHOULD STILL MANAGE UPPER
20S TO MID 30S FOR MOST AREAS.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
NEARLY ZONAL UPPER LEVEL FLOW ON WEDNESDAY WITH NEAR NORMAL SFC
TEMPS GIVES WAY TO AN ARCTIC FRONT INTRUDING FROM THE NORTHWEST
AND A SFC LOW MOVING THROUGH THE CENTRAL PLAINS ON THURSDAY. THE
GFS IS A LITTLE SLOWER TO PROGRESS THE PRECIP SOUTH WITH THE FRONT
AND HANGS IT AROUND A LITTLE LONGER. WITH SFC HIGH PRESSURE
SETTLING OVER THE REGION ON FRIDAY BELIEVE THE ECMWF AND THE
ALLBLEND ARE A BETTER BET WITH ALL PRECIP EXITING THU NIGHT.
SIGNIFICANTLY COOLER TEMPS AND DRIER CONDITIONS WILL THEN PERSIST
THROUGH THE WEEKEND AS NORTHWEST FLOW ALOFT TAKES HOLD ONCE AGAIN.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AN AREA OF WAA LIGHT SNOW IS BEGINNING ACROSS THE REGION AND
CURRENTLY AFFECTING KABR. THIS SNOW WILL ALSO MOVE INTO KMBG LATER
THIS MORNING. WHILE VSBY RESTRICTIONS WILL BE LIMITED CIGS WILL
FALL INTO THE MVFR RANGE FOR MUCH OF THE DAY BEFORE LIFTING BY
THIS EVENING. KPIR IS EXPECTED TO REMAIN VFR.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...FOWLE
SHORT TERM...TMT
LONG TERM...WISE
AVIATION...WISE
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
334 AM CST SUN DEC 15 2013
.SHORT TERM...TODAY THROUGH TUESDAY
LOCATION OF SHARP WARM FRONT A NO-BRAINER EARLY THIS MORNING AS IT
IS EASILY NOTICEABLE ON SFC OBS. FAITH AND PHILIP ARE 36 AND 37
DEGREES RESPECTIVELY WITH A NORTHWEST WIND...WHILE MOBRIDGE AND
PIERRE ARE STILL IN THE LOWER TEENS WITH A SOUTHEAST WIND. THIS
FRONT CONTINUES NORTHWEST INTO SOUTHWEST NORTH DAKOTA. AS
ADVERTISED...LIGHT SNOW IS ONGOING AHEAD OF THE FRONT WITHIN ZONE
OF LIFT AND FORCING...MAINLY FROM NORTHWEST NORTH DAKOTA AND JUST
NOW INTO NORTH CENTRAL SOUTH DAKOTA. MODELS SEEM TO BE A FEW HOURS
QUICKER WITH THE ONSET OF LIGHT SNOW SO HAVE MADE THE APPROPRIATE
ADJUSTMENTS IN WX/POP GRIDS. MODELS STILL IN RATHER GOOD AGREEMENT
AS WELL...BRINGING A SWATH OF LIGHT SNOW RIGHT DOWN THROUGH THE
NORTHEAST QUARTER OF SOUTH DAKOTA INTO WEST CENTRAL MINNESOTA. A
BIT HARDER TO NAIL DOWN WITH MORE SPECIFICITY THE ACTUAL AREA OF
SLIGHTLY ENHANCED SNOWFALL...BUT INDICATIONS IN MODELS ARE THAT IT
ACTUALLY MIGHT BE RIGHT DOWN THROUGH ABERDEEN TO NEAR
WATERTOWN...SO HAVE SLIGHTLY HIGHER SNOWFALL TOTALS IN THIS
AREA...AROUND AN INCH OR SLIGHTLY HIGHER. SOME OF THE HI RES
MODELS SHOWING THE SNOW MIGHT BE ENDING A BIT QUICKER AS
WELL...DUE TO THE EARLIER ONSET. LATEST RUN OF THE HRRR ACTUALLY
SHOWING MOST SNOW OUT OF THE AREA BY 20Z OR 21Z. A TREND TO WATCH
THROUGH THE DAY.
AFTER THE BULK OF THE SNOWFALL ENDS BY LATE AFTERNOON...ATTENTION
THEN TURNS TO THE EASTWARD PROGRESSION OF THE WARM FRONT AND
DETERMINING JUST HOW WARM TEMPS WILL GET ON MONDAY. MODELS DO NOT
SHOW MUCH MOVEMENT OF THE FRONT AT ALL TODAY...STILL HUNG UP NEAR
THE MISSOURI RIVER BY 00Z THIS EVENING. BUT OVERNIGHT...THERE IS
FINALLY A PUSH TO THE EAST WHICH SHOULD TAKE IT THROUGH MOST IF
NOT ALL THE CWA BY 12Z MONDAY MORNING. THUS...WILL SEE SLOWLY
RISING TEMPS THROUGH THE NIGHT FOR EASTERN AREAS AS THIS FRONT
MOVES THROUGH. DID NOT STRAY MUCH AT ALL FROM PREVIOUS FORECAST
FOR HIGHS ON MONDAY...THEY STILL SEEM IN GOOD SHAPE AT THIS TIME.
MOST AREAS WILL RISE INTO THE 30S AND LOW 40S...EVEN WITH THE SNOW
COVER. WARMEST TEMPS WILL BE OVER THE SOUTHWEST CWA. TUESDAY
SHAPING UP TO NOT BE THAT BAD OF A DAY EITHER. TEMPS ALOFT COOL
SLIGHTLY AND MIXING WILL BE LESS...BUT SHOULD STILL MANAGE UPPER
20S TO MID 30S FOR MOST AREAS.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
NEARLY ZONAL UPPER LEVEL FLOW ON WEDNESDAY WITH NEAR NORMAL SFC
TEMPS GIVES WAY TO AN ARCTIC FRONT INTRUDING FROM THE NORTHWEST
AND A SFC LOW MOVING THROUGH THE CENTRAL PLAINS ON THURSDAY. THE
GFS IS A LITTLE SLOWER TO PROGRESS THE PRECIP SOUTH WITH THE FRONT
AND HANGS IT AROUND A LITTLE LONGER. WITH SFC HIGH PRESSURE
SETTLING OVER THE REGION ON FRIDAY BELIEVE THE ECMWF AND THE
ALLBLEND ARE A BETTER BET WITH ALL PRECIP EXITING THU NIGHT.
SIGNIFICANTLY COOLER TEMPS AND DRIER CONDITIONS WILL THEN PERSIST
THROUGH THE WEEKEND AS NORTHWEST FLOW ALOFT TAKES HOLD ONCE AGAIN.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CIGS AND VISBY ARE EXPECTED FOR THE AREA...THOUGH KABR MAY SEE
WIDELY INTERMITTENT VISBY REDUCTIONS TO 5SM. WINDS WILL PRIMARILY
REMAIN OUT OF THE EAST.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...TMT
LONG TERM...WISE
AVIATION...CONNELLY
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
652 AM EST SUN DEC 15 2013
.SYNOPSIS...
LOW PRESSURE WAS DEEPENING OFF THE NEW JERSEY COAST THIS MORNING
AND WILL MOVE ALONG THE NEW ENGLAND COAST TONIGHT. A SERIES OF
WEAK LOW PRESSURE SYSTEMS WILL TRACK FROM THE NORTHERN PLAINS
THROUGH THE EASTERN UNITED STATES TONIGHT THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 600 AM EST SUNDAY...
JUST STARTING TO SEE SOME CLEARING ON SATELLITE PICTURES ALONG
AND EAST OF THE BLUE RIDGE BEHIND THE SHORT WAVE OVER MARYLAND.
THE WET GROUND FROM THE RAIN SATURDAY COMBINED WITH THE CLEARING
SKY WILL LEAD TO MORE FOG THROUGH 9AM. VISIBILITIES WERE DOWN TO
ONE QUARTER MILE AT MOUNT AIRY AND NORTH WILKESBORO. IN
COORDINATION WITH NWSFO GSP HAVE ISSUED A DENSE FOG ADVISORY FOR
THE FOOTHILLS UP THROUGH FRANKLIN COUNTY. WINDS WERE GUSTING OUT
OF THE WEST BUT WILL INCREASE ENOUGH AFTER 10AM/14Z FOR
DOWNSLOPING AND DRYING TO HELP ERODE THE FOG.
LOCAL WRF AND HRRR HAD EDGE OF SHORT WAVE IN THE SOUTHERN
APPALACHIANS CLEARING THE EASTERN COUNTY WARNING AREA BY 10Z/5AM.
THE NEXT SHORT WAVE COMES OUT OF THE OHIO VALLEY AND ACROSS THE AREA
THIS MORNING.
FOLLOWING THE SHORT WAVES TODAY...REGION STAYS UNDER PERSISTENT LONG
WAVE TROF AND NORTHWEST FLOW ALOFT. EXPECT A BRIEF RISE IN
TEMPERATURE JUST BEHIND THE SHORT WAVE THEN FALLING TEMPERATURES
AROUND SUNRISE. WITH COLD AIR ADVECTION AND LITTLE SUNSHINE
TODAY....MOST LOCATIONS WEST OF THE BLUE RIDGE WILL HAVE A MINIMAL
RISE IN TEMPERATURES. STAYED CLOSER TO THE COOLER BIAS CORRECTED
MAV GUIDANCE FOE TEMPERATURES THROUGH THE EVENING.
MSAS ANALYSIS SHOWS LARGE PRESSURE FALLS NEAR LONG ISLAND WHERE
THE SURFACE LOW IS DEEPENING. PRESSURE RISES AND COLD AIR
ADVECTION OVER OUR FORECAST AREA WILL LEAD TO GUSTY WET WINDS. THE
DOWNSLOPE WINDS AND EXIT OF DEEPER MOISTURE WILL RESULT IN
CLEARING EAST OF THE BLUE RIDGE BY THIS AFTERNOON. PERSISTENT LOW
LEVEL MOISTURE AND UPSLOPE WINDS WILL HOLD CLOUDS IN THE WESTERN
MOUNTAINS OF THE FORECAST AREA THROUGH TONIGHT.
ANOTHER SHORT WAVE COMES THROUGH THE NORTHWEST FLOW ALOFT TONIGHT...
ADDING SOME LIFT TO THE UPSLOPE WINDS AND PROLONGING THE PROBABILITY
OF SNOW SHOWERS THROUGH MONDAY MORNING. MODELS SHOW A SUBTLE
INCREASE IN PRECIPITABLE WATER AND DEPTH OF MOISTURE AS THIS FEATURE
COMES THROUGH. WILL MAINTAIN SNOW SHOWERS ON THE FAR WESTERN
SLOPES FROM GREENBRIER TO TAZEWELL COUNTY LATE TONIGHT.
850 MB TEMPERATURES DROP TODAY BUT BEST PUSH OF COLDER
AIR...ESPECIALLY INTO THE EASTERN COUNTY WARNING AREA WILL BE
TONIGHT. LOW LEVEL JET IN THE 40 TO 50 KNOT RANGE WILL SUPPORT
SURFACE WIND GUSTS OF 25 TO 35 KNOTS/28-40 MPH TODAY WITH ANOTHER
SURGE OF STRONGER WINDS BEHIND THE SHORT WAVE TONIGHT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 250 AM EST SUNDAY...
DURING MOST OF THIS SEGMENT OF THE FORECAST PERIOD THE REGION WILL
REMAIN IN NORTHWEST FLOW THANKS TO A OVERALL LONGWAVE TROUGH PATTERN
OVER SOUTH CENTRAL AND SOUTHEAST CANADA. WITHIN THE PARENT LONGWAVE
PATTERN...A SERIES OF SHORTWAVE TROUGHS ARE PROGGED TO PROGRESS
THROUGH THE GREAT LAKES AND THEN NEW ENGLAND REGIONS OF THE U.S.
EACH OF THESE WILL HAVE A COMPARABLE IMPACT ON THE WEATHER ACROSS
OUR PART OF THE COUNTRY.
THE BULK OF THE UPPER LEVEL DYNAMICS AND ASSOCIATED MOISTURE WILL
REMAIN NORTH OF THE FORECAST AREA. THE SOUTHERN TAIL END OF EACH
SYSTEM WILL CLIP AREAS SOUTH TO ROUGHLY THE I-64 CORRIDOR
WEST OF COVINGTON VA...AND THE I-77 CORRIDOR SOUTH TO ROUGHLY
BLUEFIELD WV.
THE FIRST...AND WEAKEST OF THESE IMPULSES...WILL CROSS THE AREA LATE
SUNDAY NIGHT INTO EARLY MONDAY. THE SECOND...AND NEXT
STRONGEST...MONDAY NIGHT INTO EARLY TUESDAY. THE FINAL AND STRONGEST
ONE...TUESDAY AFTERNOON INTO TUESDAY EVENING.
WHILE THERE WILL BE SOME LEVEL GUSTINESS WITH THE FIRST
IMPULSE...WINDS WILL INCREASE SIGNIFICANTLY WITH THE PASSAGE OF THE
SECOND SHORTWAVE TROUGH...AND EVEN MORE SO IN THE WAKE OF THE THIRD.
SOLUTIONS AMONG THE VARIOUS MODELS PLACE NORTHWEST 850 MB WINDS
ACROSS THE AREA TUESDAY EVENING THROUGH EARLY WEDNESDAY MORNING IN
THE 45 TO 55 KT RANGE WITH GOOD CROSS BARRIER FLOW. IF THIS PATTERN
HOLDS...THIS SCENARIO WOULD BE FAVORABLE FOR AT LEAST WIND ADVISORY
GUSTS ACROSS THE MOUNTAINS. WILL HIGHLIGHT THIS POTENTIAL IN THE
HAZARDOUS WEATHER OUTLOOK.
WE ARE EXPECTING A PATTERN SHIFT WEDNESDAY INTO WEDNESDAY NIGHT. THE
UPPER LEVEL FLOW BECOMES MORE ZONAL TO SLIGHTLY SOUTHWEST. ANY
IMPULSES IN THE NORTHERN STREAM WILL REMAIN WELL NORTH OF THE AREA.
WITH THE NORTHWEST FLOW BACKING MORE WEST TO SOUTHWEST...WE EXPECT
LESS CLOUD COVER ACROSS THE MOUNTAINS.
DURING THIS ENTIRE PORTION OF THE FORECAST PERIOD...LOCATIONS ACROSS
THE PIEDMONT...ESPECIALLY NEAR THE NC/VA BORDER...ARE EXPECTED TO
SEE LIMITED CLOUD COVER. WINDS WILL ALSO BECOME GUSTY...BUT NOT AS
STRONG AS THOSE ANTICIPATED ACROSS THE MOUNTAINS.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 302 PM EST SATURDAY...
BOTH THE 12Z GFS/ECM AGREE THAT A SURFACE RIDGE WILL PASS OVER THE
REGION WEDNESDAY...THEN MOVE OFF THE COAST THURSDAY. THIS RIDGE WILL
KEEP THE AREA CHILLY WITH COLDER THAN NORMAL TEMPERATURES FOR
WEDNESDAY. AS THIS RIDGE MOVES EAST THURSDAY...SOUTHWESTERLY FLOW
WILL PREVAIL. TEMPERATURES WILL MODERATE TO NORMAL ON THURSDAY WITH
WARM THAN NORMAL TEMPERATURES ON FRIDAY...POSSIBLY CONTINUING INTO
SATURDAY. THE AREA SHOULD SEE WIDESPREAD 50S ON FRIDAY...AND MID TO
UPPER 50S WEST AND LOW TO MID 60S EAST ON SATURDAY. OF
COURSE...THESE TEMPERATURES WILL BE DEPENDENT ON WHEN THE NEXT COLD
FRONT INFLUENCES OUR WEATHER. THIS PART OF THE FORECAST IS WHERE THE
MODELS DIFFER.
THE 12Z GFS DEVELOPS A SURFACE LOW ALONG A COLD FRONT IN THE CENTRAL
PLAINS THURSDAY NIGHT. THIS LOW IS EXPECTED TO TRACK NORTHEAST TO
NEW ENGLAND BY FRIDAY EVENING. THE TRAILING COLD FRONT WILL BE
SLOWLY MOVING ACROSS THE OHIO-TENN VALLEYS FRIDAY...STALLING ALONG
THE WESTERN APPALACHIANS FRIDAY NIGHT. ANOTHER SURFACE LOW DEVELOPS
ON THE LEE SIDE OF THE SOUTHERN APPALACHIANS...DRAGGING THE FRONT AND
ASSOCIATED RAIN SHOWERS ACROSS THE REGION ON SATURDAY. IF THIS
VERIFIES...SATURDAYS TEMPERATURES WILL NOT BE AS WARM AS FORECASTED.
THE 12Z ECM DEVELOPS A SURFACE LOW ALONG THE FRONT AND TRACKS IT
NORTHEAST BUT OVER QUEBEC. THIS FRONT WILL THEN STALL OVER THE OHIO-
TENN VALLEY ON FRIDAY. A WAVE OF LOW PRESSURE IS EXPECTED TO TRACK
ALONG THIS FRONT FRIDAY NIGHT INTO SATURDAY. ANOTHER WAVE IS
FORECASTED TO TRACK ALONG THE FRONT...STILL OVER THE OHIO
VALLEY...SATURDAY NIGHT INTO SUNDAY. THE 12Z ECM WOULD KEEP THE
FORECAST AREA IN THE WARM SECTOR INTO SATURDAY...POSSIBLY SUNDAY.
THE ECM ALSO KEEPS BULK OF THE RAIN NORTH OF THE AREA WITH A
POSSIBLE PASSING MOUNTAIN SHOWER FRIDAY AND SATURDAY.
FOR THIS FORECAST PACKAGE...FAVORING THE ECM OVER THE GFS (70/30)
ESPECIALLY ON TEMPERATURES. FOR POPS...ADDED LOW CHANCE POPS (30
PERCENT) IN THE WEST FRIDAY NIGHT...THEN ACROSS THE ENTIRE AREA ON
SATURDAY (30 PERCENT).
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 645 AM EST SUNDAY...
LOW PRESSURE DEEPENING OFF THE NEW JERSEY COAST AND THE
ASSOCIATED SHORT WAVE TROF OVER VIRGINIA AND NORTH CAROLINA WERE
PRODUCING GUSTY WEST WINDS ACROSS THE REGION. ON THE EAST SIDE OF
THE BLUE RIDGE DOWNSLOPING WILL CLEAR OUT THE CLOUDS AT KLYH AND
KDAN BY 15Z/10AM. UNTIL THEN PERIODS OF LIFR FOG AND CLOUDS ARE
EXPECTED.
IN THE MOUNTAINS CEILINGS FOR MUCH OF THE DAY WILL BE MVFR WITH
SCATTERED RAIN AND SNOW SHOWERS. WIND GUSTS FROM THE WEST AND
NORTHWEST WILL REACH 25 TO 35 KNOTS...ESPECIALLY AT HIGHER
ELEVATIONS. WINDS SPEED WILL SUBSIDE IN THE EVENING WITH THE
EXCEPTION OF AREAS ALONG THE BLUE RIDGE...KROA AND KBCB.
ANOTHER SHORT WAVE WILL APPROACH THE REGION FROM THE NORTHWEST
TONIGHT. THIS WILL PROLONG THE MVFR CLOUDS AT KBLF AND KLWB AND
WILL BRING SNOW SHOWERS TO THE WESTERN UPSLOPE AREAS. CONDITIONS
ARE EXPECTED TO REMAIN VFR EAST OF THE BLUE RIDGE ALTHOUGH WIND
WILL INCREASE BEHIND THE WAVE.
HIGH PRESSURE BUILDS INTO THE REGION FROM THE WEST MONDAY...ALLOWING
UPSLOPING CLOUDS TO GRADUALLY ERODE OVER THE MOUNTAINS...BRINGING
A RETURN TO VFR WEATHER WITH UNRESTRICTED CONDITIONS...EVEN IN THE
UPSLOPE AREAS...BY MIDDAY MONDAY. DRY WEATHER WITH MAINLY VFR
WEATHER IS THEN EXPECTED IN MOST AREAS INTO MID WEEK. THERE WILL
BE A PERIOD OF STRONG GUSTY WINDS IN THE MOUNTAINS TUESDAY INTO
WEDNESDAY...ALONG WITH UPSLOPE CLOUDS WITH MVFR CEILINGS.
HIGH CONFIDENCE ON THE CLEARING TODAY EAST OF THE BLUE RIDGE AND
THE CONTINUATION OF VFR CONDITIONS THROUGH MONDAY. MEDIUM
CONFIDENCE ON THE EXTENT OF SNOW SHOWERS TONIGHT IN SOUTHEAST WEST
VIRGINIA WITH THE NEXT SHORT WAVE.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR VAZ032-033-
043.
NC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR NCZ003>005-
019-020.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...DS
LONG TERM...RCS
AVIATION...AMS/RCS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
605 AM EST SUN DEC 15 2013
.SYNOPSIS...
LOW PRESSURE WAS DEEPENING OFF THE NEW JERSEY COAST THIS MORNING
AND WILL MOVE ALONG THE NEW ENGLAND COAST TONIGHT. A SERIES OF
WEAK LOW PRESSURE SYSTEMS WILL TRACK FROM THE NORTHERN PLAINS
THROUGH THE EASTERN UNITED STATES TONIGHT THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 600 AM EST SUNDAY...
JUST STARTING TO SEE SOME CLEARING ON SATELLITE PICTURES ALONG
AND EAST OF THE BLUE RIDGE BEHIND THE SHORT WAVE OVER MARYLAND.
THE WET GROUND FROM THE RAIN SATURDAY COMBINED WITH THE CLEARING
SKY WILL LEAD TO MORE FOG THROUGH 9AM. VISIBILITIES WERE DOWN TO
ONE QUARTER MILE AT MOUNT AIRY AND NORTH WILKESBORO. IN
COORDINATION WITH NWSFO GSP HAVE ISSUED A DENSE FOG ADVISORY FOR
THE FOOTHILLS UP THROUGH FRANKLIN COUNTY. WINDS WERE GUSTING OUT
OF THE WEST BUT WILL INCREASE ENOUGH AFTER 10AM/14Z FOR
DOWNSLOPING AND DRYING TO HELP ERODE THE FOG.
LOCAL WRF AND HRRR HAD EDGE OF SHORT WAVE IN THE SOUTHERN
APPALACHIANS CLEARING THE EASTERN COUNTY WARNING AREA BY 10Z/5AM.
THE NEXT SHORT WAVE COMES OUT OF THE OHIO VALLEY AND ACROSS THE AREA
THIS MORNING.
FOLLOWING THE SHORT WAVES TODAY...REGION STAYS UNDER PERSISTENT LONG
WAVE TROF AND NORTHWEST FLOW ALOFT. EXPECT A BRIEF RISE IN
TEMPERATURE JUST BEHIND THE SHORT WAVE THEN FALLING TEMPERATURES
AROUND SUNRISE. WITH COLD AIR ADVECTION AND LITTLE SUNSHINE
TODAY....MOST LOCATIONS WEST OF THE BLUE RIDGE WILL HAVE A MINIMAL
RISE IN TEMPERATURES. STAYED CLOSER TO THE COOLER BIAS CORRECTED
MAV GUIDANCE FOE TEMPERATURES THROUGH THE EVENING.
MSAS ANALYSIS SHOWS LARGE PRESSURE FALLS NEAR LONG ISLAND WHERE
THE SURFACE LOW IS DEEPENING. PRESSURE RISES AND COLD AIR
ADVECTION OVER OUR FORECAST AREA WILL LEAD TO GUSTY WET WINDS. THE
DOWNSLOPE WINDS AND EXIT OF DEEPER MOISTURE WILL RESULT IN
CLEARING EAST OF THE BLUE RIDGE BY THIS AFTERNOON. PERSISTENT LOW
LEVEL MOISTURE AND UPSLOPE WINDS WILL HOLD CLOUDS IN THE WESTERN
MOUNTAINS OF THE FORECAST AREA THROUGH TONIGHT.
ANOTHER SHORT WAVE COMES THROUGH THE NORTHWEST FLOW ALOFT TONIGHT...
ADDING SOME LIFT TO THE UPSLOPE WINDS AND PROLONGING THE PROBABILITY
OF SNOW SHOWERS THROUGH MONDAY MORNING. MODELS SHOW A SUBTLE
INCREASE IN PRECIPITABLE WATER AND DEPTH OF MOISTURE AS THIS FEATURE
COMES THROUGH. WILL MAINTAIN SNOW SHOWERS ON THE FAR WESTERN
SLOPES FROM GREENBRIER TO TAZEWELL COUNTY LATE TONIGHT.
850 MB TEMPERATURES DROP TODAY BUT BEST PUSH OF COLDER
AIR...ESPECIALLY INTO THE EASTERN COUNTY WARNING AREA WILL BE
TONIGHT. LOW LEVEL JET IN THE 40 TO 50 KNOT RANGE WILL SUPPORT
SURFACE WIND GUSTS OF 25 TO 35 KNOTS/28-40 MPH TODAY WITH ANOTHER
SURGE OF STRONGER WINDS BEHIND THE SHORT WAVE TONIGHT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 250 AM EST SUNDAY...
DURING MOST OF THIS SEGMENT OF THE FORECAST PERIOD THE REGION WILL
REMAIN IN NORTHWEST FLOW THANKS TO A OVERALL LONGWAVE TROUGH PATTERN
OVER SOUTH CENTRAL AND SOUTHEAST CANADA. WITHIN THE PARENT LONGWAVE
PATTERN...A SERIES OF SHORTWAVE TROUGHS ARE PROGGED TO PROGRESS
THROUGH THE GREAT LAKES AND THEN NEW ENGLAND REGIONS OF THE U.S.
EACH OF THESE WILL HAVE A COMPARABLE IMPACT ON THE WEATHER ACROSS
OUR PART OF THE COUNTRY.
THE BULK OF THE UPPER LEVEL DYNAMICS AND ASSOCIATED MOISTURE WILL
REMAIN NORTH OF THE FORECAST AREA. THE SOUTHERN TAIL END OF EACH
SYSTEM WILL CLIP AREAS SOUTH TO ROUGHLY THE I-64 CORRIDOR
WEST OF COVINGTON VA...AND THE I-77 CORRIDOR SOUTH TO ROUGHLY
BLUEFIELD WV.
THE FIRST...AND WEAKEST OF THESE IMPULSES...WILL CROSS THE AREA LATE
SUNDAY NIGHT INTO EARLY MONDAY. THE SECOND...AND NEXT
STRONGEST...MONDAY NIGHT INTO EARLY TUESDAY. THE FINAL AND STRONGEST
ONE...TUESDAY AFTERNOON INTO TUESDAY EVENING.
WHILE THERE WILL BE SOME LEVEL GUSTINESS WITH THE FIRST
IMPULSE...WINDS WILL INCREASE SIGNIFICANTLY WITH THE PASSAGE OF THE
SECOND SHORTWAVE TROUGH...AND EVEN MORE SO IN THE WAKE OF THE THIRD.
SOLUTIONS AMONG THE VARIOUS MODELS PLACE NORTHWEST 850 MB WINDS
ACROSS THE AREA TUESDAY EVENING THROUGH EARLY WEDNESDAY MORNING IN
THE 45 TO 55 KT RANGE WITH GOOD CROSS BARRIER FLOW. IF THIS PATTERN
HOLDS...THIS SCENARIO WOULD BE FAVORABLE FOR AT LEAST WIND ADVISORY
GUSTS ACROSS THE MOUNTAINS. WILL HIGHLIGHT THIS POTENTIAL IN THE
HAZARDOUS WEATHER OUTLOOK.
WE ARE EXPECTING A PATTERN SHIFT WEDNESDAY INTO WEDNESDAY NIGHT. THE
UPPER LEVEL FLOW BECOMES MORE ZONAL TO SLIGHTLY SOUTHWEST. ANY
IMPULSES IN THE NORTHERN STREAM WILL REMAIN WELL NORTH OF THE AREA.
WITH THE NORTHWEST FLOW BACKING MORE WEST TO SOUTHWEST...WE EXPECT
LESS CLOUD COVER ACROSS THE MOUNTAINS.
DURING THIS ENTIRE PORTION OF THE FORECAST PERIOD...LOCATIONS ACROSS
THE PIEDMONT...ESPECIALLY NEAR THE NC/VA BORDER...ARE EXPECTED TO
SEE LIMITED CLOUD COVER. WINDS WILL ALSO BECOME GUSTY...BUT NOT AS
STRONG AS THOSE ANTICIPATED ACROSS THE MOUNTAINS.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 302 PM EST SATURDAY...
BOTH THE 12Z GFS/ECM AGREE THAT A SURFACE RIDGE WILL PASS OVER THE
REGION WEDNESDAY...THEN MOVE OFF THE COAST THURSDAY. THIS RIDGE WILL
KEEP THE AREA CHILLY WITH COLDER THAN NORMAL TEMPERATURES FOR
WEDNESDAY. AS THIS RIDGE MOVES EAST THURSDAY...SOUTHWESTERLY FLOW
WILL PREVAIL. TEMPERATURES WILL MODERATE TO NORMAL ON THURSDAY WITH
WARM THAN NORMAL TEMPERATURES ON FRIDAY...POSSIBLY CONTINUING INTO
SATURDAY. THE AREA SHOULD SEE WIDESPREAD 50S ON FRIDAY...AND MID TO
UPPER 50S WEST AND LOW TO MID 60S EAST ON SATURDAY. OF
COURSE...THESE TEMPERATURES WILL BE DEPENDENT ON WHEN THE NEXT COLD
FRONT INFLUENCES OUR WEATHER. THIS PART OF THE FORECAST IS WHERE THE
MODELS DIFFER.
THE 12Z GFS DEVELOPS A SURFACE LOW ALONG A COLD FRONT IN THE CENTRAL
PLAINS THURSDAY NIGHT. THIS LOW IS EXPECTED TO TRACK NORTHEAST TO
NEW ENGLAND BY FRIDAY EVENING. THE TRAILING COLD FRONT WILL BE
SLOWLY MOVING ACROSS THE OHIO-TENN VALLEYS FRIDAY...STALLING ALONG
THE WESTERN APPALACHIANS FRIDAY NIGHT. ANOTHER SURFACE LOW DEVELOPS
ON THE LEE SIDE OF THE SOUTHERN APPALACHIANS...DRAGGING THE FRONT AND
ASSOCIATED RAIN SHOWERS ACROSS THE REGION ON SATURDAY. IF THIS
VERIFIES...SATURDAYS TEMPERATURES WILL NOT BE AS WARM AS FORECASTED.
THE 12Z ECM DEVELOPS A SURFACE LOW ALONG THE FRONT AND TRACKS IT
NORTHEAST BUT OVER QUEBEC. THIS FRONT WILL THEN STALL OVER THE OHIO-
TENN VALLEY ON FRIDAY. A WAVE OF LOW PRESSURE IS EXPECTED TO TRACK
ALONG THIS FRONT FRIDAY NIGHT INTO SATURDAY. ANOTHER WAVE IS
FORECASTED TO TRACK ALONG THE FRONT...STILL OVER THE OHIO
VALLEY...SATURDAY NIGHT INTO SUNDAY. THE 12Z ECM WOULD KEEP THE
FORECAST AREA IN THE WARM SECTOR INTO SATURDAY...POSSIBLY SUNDAY.
THE ECM ALSO KEEPS BULK OF THE RAIN NORTH OF THE AREA WITH A
POSSIBLE PASSING MOUNTAIN SHOWER FRIDAY AND SATURDAY.
FOR THIS FORECAST PACKAGE...FAVORING THE ECM OVER THE GFS (70/30)
ESPECIALLY ON TEMPERATURES. FOR POPS...ADDED LOW CHANCE POPS (30
PERCENT) IN THE WEST FRIDAY NIGHT...THEN ACROSS THE ENTIRE AREA ON
SATURDAY (30 PERCENT).
&&
.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
AS OF 130 AM EST SUNDAY...
POOR FLYING CONDITIONS EXPECTED FOR THE FIRST 6-10 HOURS OF THE
PERIOD WITH LOW CEILINGS/FOG/DRIZZLE. OUTSIDE OF WESTERN
SLOPES...CONDITIONS WILL BEGIN TO IMPROVE FROM WEST TO EAST AS
WINDS TURN TO THE WEST. FIRST TO GO WILL BE THE DRIZZLE AND
FOG...THEN CEILINGS LIFT FROM IFR TO VFR BY EARLY SUNDAY MORNING.
WESTERN SLOPES WILL KEEP IFR RESTRICTIONS THROUGH SUNDAY MORNING
WITH A MOIST WEST WIND AND UPSLOPE SNOW SHOWERS. SNOW SHOWERS WILL
TAPER TO FLURRIES DURING THE AFTERNOON WITH CEILINGS LIFTING TO
MVFR.
WINDS SPEED WILL INCREASE THROUGH THE MORNING AND SUBSIDE IN THE
EVENING WITH THE EXCEPTION OF AREAS ALONG THE BLUE RIDGE
(ROA/BCB). WEST WINDS OF 10-20 KNOTS GUSTING TO 20-30 KNOTS ARE
POSSIBLE ACROSS THE ENTIRE FORECAST AREA DURING THE DAY SUNDAY.
THE HIGHER SPEEDS ARE RESERVED FOR LOCATION ALONG THE BLUE RIDGE.
CONFIDENCE IS FAIRLY HIGH WITH IFR CONDITIONS REMAINING THROUGH
THE FIRST 3-6 HOURS OF THE TAF PERIOD. MEDIUM CONFIDENCE ON TIMING
OF IMPROVING CONDITIONS THROUGH 12Z SUN. HIGH CONFIDENCE IN WIND
DIRECTION AND SPEED DURING THE PERIOD.
HIGH PRESSURE EXPECTED TO BUILD INTO THE REGION FROM THE WEST
MONDAY...ALLOWING UPSLOPING CLOUDS TO GRADUALLY ERODE OVER THE
MOUNTAINS...BRINGING A RETURN TO VFR WEATHER WITH UNRESTRICTED
CONDITIONS...EVEN IN THE UPSLOPE AREAS...BY MIDDAY MONDAY. DRY
WEATHER WITH MAINLY VFR WEATHER IS THEN EXPECTED IN MOST AREAS
INTO MID WEEK...WITH PERHAPS THE EXCEPTION OF A PERIOD OF SOME
UPSLOPING CLOUDS WITH MVFR CEILINGS ACROSS THE WESTERN FLANKS OF
THE APPALACHIANS LATER TUESDAY INTO WEDNESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR VAZ032-033-
043.
NC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR NCZ003>005-
019-020.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...DS
LONG TERM...RCS
AVIATION...AMS/RCS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
455 AM EST SUN DEC 15 2013
.SYNOPSIS...
LOW PRESSURE WAS DEEPENING OFF THE NEW JERSEY COAST THIS MORNING
AND WILL MOVE ALONG THE NEW ENGLAND COAST TONIGHT. A SERIES OF
WEAK LOW PRESSURE SYSTEMS WILL TRACK FROM THE NORTHERN PLAINS
THROUGH THE EASTERN UNITED STATES TONIGHT THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 500 AM EST SUNDAY...
LOCAL WRF AND HRRR HAD EDGE OF SHORT WAVE IN THE SOUTHERN
APPALACHIANS CLEARING THE EASTERN COUNTY WARNING AREA BY 10Z/5AM.
THE NEXT SHORT WAVE COMES OUT OF THE OHIO VALLEY AND ACROSS THE AREA
THIS MORNING.
FOLLOWING THE SHORT WAVES TODAY...REGION STAYS UNDER PERSISTENT LONG
WAVE TROF AND NORTHWEST FLOW ALOFT. EXPECT A BRIEF RISE IN
TEMPERATURE JUST BEHIND THE SHORT WAVE THEN FALLING TEMPERATURES
AROUND SUNRISE. WITH COLD AIR ADVECTION AND LITTLE SUNSHINE
TODAY....MOST LOCATIONS WEST OF THE BLUE RIDGE WILL HAVE A MINIMAL
RISE IN TEMPERATURES. STAYED CLOSER TO THE COOLER BIAS CORRECTED
MAV GUIDANCE FOE TEMPERATURES THROUGH THE EVENING.
MSAS ANALYSIS SHOWS LARGE PRESSURE FALLS NEAR LONG ISLAND WHERE
THE SURFACE LOW IS DEEPENING. PRESSURE RISES AND COLD AIR
ADVECTION OVER OUR FORECAST AREA WILL LEAD TO GUSTY WET WINDS. THE
DOWNSLOPE WINDS AND EXIT OF DEEPER MOISTURE WILL RESULT IN
CLEARING EAST OF THE BLUE RIDGE BY THIS AFTERNOON. PERSISTENT LOW
LEVEL MOISTURE AND UPSLOPE WINDS WILL HOLD CLOUDS IN THE WESTERN
MOUNTAINS OF THE FORECAST AREA THROUGH TONIGHT.
ANOTHER SHORT WAVE COMES THROUGH THE NORTHWEST FLOW ALOFT TONIGHT...
ADDING SOME LIFT TO THE UPSLOPE WINDS AND PROLONGING THE PROBABILITY
OF SNOW SHOWERS THROUGH MONDAY MORNING. MODELS SHOW A SUBTLE
INCREASE IN PRECIPITABLE WATER AND DEPTH OF MOISTURE AS THIS FEATURE
COMES THROUGH. WILL MAINTAIN SNOW SHOWERS ON THE FAR WESTERN
SLOPES FROM GREENBRIER TO TAZEWELL COUNTY LATE TONIGHT.
850 MB TEMPERATURES DROP TODAY BUT BEST PUSH OF COLDER
AIR...ESPECIALLY INTO THE EASTERN COUNTY WARNING AREA WILL BE
TONIGHT. LOW LEVEL JET IN THE 40 TO 50 KNOT RANGE WILL SUPPORT
SURFACE WIND GUSTS OF 25 TO 35 KNOTS/28-40 MPH TODAY WITH ANOTHER
SURGE OF STRONGER WINDS BEHIND THE SHORT WAVE TONIGHT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 250 AM EST SUNDAY...
DURING MOST OF THIS SEGMENT OF THE FORECAST PERIOD THE REGION WILL
REMAIN IN NORTHWEST FLOW THANKS TO A OVERALL LONGWAVE TROUGH PATTERN
OVER SOUTH CENTRAL AND SOUTHEAST CANADA. WITHIN THE PARENT LONGWAVE
PATTERN...A SERIES OF SHORTWAVE TROUGHS ARE PROGGED TO PROGRESS
THROUGH THE GREAT LAKES AND THEN NEW ENGLAND REGIONS OF THE U.S.
EACH OF THESE WILL HAVE A COMPARABLE IMPACT ON THE WEATHER ACROSS
OUR PART OF THE COUNTRY.
THE BULK OF THE UPPER LEVEL DYNAMICS AND ASSOCIATED MOISTURE WILL
REMAIN NORTH OF THE FORECAST AREA. THE SOUTHERN TAIL END OF EACH
SYSTEM WILL CLIP AREAS SOUTH TO ROUGHLY THE I-64 CORRIDOR
WEST OF COVINGTON VA...AND THE I-77 CORRIDOR SOUTH TO ROUGHLY
BLUEFIELD WV.
THE FIRST...AND WEAKEST OF THESE IMPULSES...WILL CROSS THE AREA LATE
SUNDAY NIGHT INTO EARLY MONDAY. THE SECOND...AND NEXT
STRONGEST...MONDAY NIGHT INTO EARLY TUESDAY. THE FINAL AND STRONGEST
ONE...TUESDAY AFTERNOON INTO TUESDAY EVENING.
WHILE THERE WILL BE SOME LEVEL GUSTINESS WITH THE FIRST
IMPULSE...WINDS WILL INCREASE SIGNIFICANTLY WITH THE PASSAGE OF THE
SECOND SHORTWAVE TROUGH...AND EVEN MORE SO IN THE WAKE OF THE THIRD.
SOLUTIONS AMONG THE VARIOUS MODELS PLACE NORTHWEST 850 MB WINDS
ACROSS THE AREA TUESDAY EVENING THROUGH EARLY WEDNESDAY MORNING IN
THE 45 TO 55 KT RANGE WITH GOOD CROSS BARRIER FLOW. IF THIS PATTERN
HOLDS...THIS SCENARIO WOULD BE FAVORABLE FOR AT LEAST WIND ADVISORY
GUSTS ACROSS THE MOUNTAINS. WILL HIGHLIGHT THIS POTENTIAL IN THE
HAZARDOUS WEATHER OUTLOOK.
WE ARE EXPECTING A PATTERN SHIFT WEDNESDAY INTO WEDNESDAY NIGHT. THE
UPPER LEVEL FLOW BECOMES MORE ZONAL TO SLIGHTLY SOUTHWEST. ANY
IMPULSES IN THE NORTHERN STREAM WILL REMAIN WELL NORTH OF THE AREA.
WITH THE NORTHWEST FLOW BACKING MORE WEST TO SOUTHWEST...WE EXPECT
LESS CLOUD COVER ACROSS THE MOUNTAINS.
DURING THIS ENTIRE PORTION OF THE FORECAST PERIOD...LOCATIONS ACROSS
THE PIEDMONT...ESPECIALLY NEAR THE NC/VA BORDER...ARE EXPECTED TO
SEE LIMITED CLOUD COVER. WINDS WILL ALSO BECOME GUSTY...BUT NOT AS
STRONG AS THOSE ANTICIPATED ACROSS THE MOUNTAINS.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 302 PM EST SATURDAY...
BOTH THE 12Z GFS/ECM AGREE THAT A SURFACE RIDGE WILL PASS OVER THE
REGION WEDNESDAY...THEN MOVE OFF THE COAST THURSDAY. THIS RIDGE WILL
KEEP THE AREA CHILLY WITH COLDER THAN NORMAL TEMPERATURES FOR
WEDNESDAY. AS THIS RIDGE MOVES EAST THURSDAY...SOUTHWESTERLY FLOW
WILL PREVAIL. TEMPERATURES WILL MODERATE TO NORMAL ON THURSDAY WITH
WARM THAN NORMAL TEMPERATURES ON FRIDAY...POSSIBLY CONTINUING INTO
SATURDAY. THE AREA SHOULD SEE WIDESPREAD 50S ON FRIDAY...AND MID TO
UPPER 50S WEST AND LOW TO MID 60S EAST ON SATURDAY. OF
COURSE...THESE TEMPERATURES WILL BE DEPENDENT ON WHEN THE NEXT COLD
FRONT INFLUENCES OUR WEATHER. THIS PART OF THE FORECAST IS WHERE THE
MODELS DIFFER.
THE 12Z GFS DEVELOPS A SURFACE LOW ALONG A COLD FRONT IN THE CENTRAL
PLAINS THURSDAY NIGHT. THIS LOW IS EXPECTED TO TRACK NORTHEAST TO
NEW ENGLAND BY FRIDAY EVENING. THE TRAILING COLD FRONT WILL BE
SLOWLY MOVING ACROSS THE OHIO-TENN VALLEYS FRIDAY...STALLING ALONG
THE WESTERN APPALACHIANS FRIDAY NIGHT. ANOTHER SURFACE LOW DEVELOPS
ON THE LEE SIDE OF THE SOUTHERN APPALACHIANS...DRAGGING THE FRONT AND
ASSOCIATED RAIN SHOWERS ACROSS THE REGION ON SATURDAY. IF THIS
VERIFIES...SATURDAYS TEMPERATURES WILL NOT BE AS WARM AS FORECASTED.
THE 12Z ECM DEVELOPS A SURFACE LOW ALONG THE FRONT AND TRACKS IT
NORTHEAST BUT OVER QUEBEC. THIS FRONT WILL THEN STALL OVER THE OHIO-
TENN VALLEY ON FRIDAY. A WAVE OF LOW PRESSURE IS EXPECTED TO TRACK
ALONG THIS FRONT FRIDAY NIGHT INTO SATURDAY. ANOTHER WAVE IS
FORECASTED TO TRACK ALONG THE FRONT...STILL OVER THE OHIO
VALLEY...SATURDAY NIGHT INTO SUNDAY. THE 12Z ECM WOULD KEEP THE
FORECAST AREA IN THE WARM SECTOR INTO SATURDAY...POSSIBLY SUNDAY.
THE ECM ALSO KEEPS BULK OF THE RAIN NORTH OF THE AREA WITH A
POSSIBLE PASSING MOUNTAIN SHOWER FRIDAY AND SATURDAY.
FOR THIS FORECAST PACKAGE...FAVORING THE ECM OVER THE GFS (70/30)
ESPECIALLY ON TEMPERATURES. FOR POPS...ADDED LOW CHANCE POPS (30
PERCENT) IN THE WEST FRIDAY NIGHT...THEN ACROSS THE ENTIRE AREA ON
SATURDAY (30 PERCENT).
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
AS OF 130 AM EST SUNDAY...
POOR FLYING CONDITIONS EXPECTED FOR THE FIRST 6-10 HOURS OF THE
PERIOD WITH LOW CEILINGS/FOG/DRIZZLE. OUTSIDE OF WESTERN
SLOPES...CONDITIONS WILL BEGIN TO IMPROVE FROM WEST TO EAST AS
WINDS TURN TO THE WEST. FIRST TO GO WILL BE THE DRIZZLE AND
FOG...THEN CEILINGS LIFT FROM IFR TO VFR BY EARLY SUNDAY MORNING.
WESTERN SLOPES WILL KEEP IFR RESTRICTIONS THROUGH SUNDAY MORNING
WITH A MOIST WEST WIND AND UPSLOPE SNOW SHOWERS. SNOW SHOWERS WILL
TAPER TO FLURRIES DURING THE AFTERNOON WITH CEILINGS LIFTING TO
MVFR.
WINDS SPEED WILL INCREASE THROUGH THE MORNING AND SUBSIDE IN THE
EVENING WITH THE EXCEPTION OF AREAS ALONG THE BLUE RIDGE
(ROA/BCB). WEST WINDS OF 10-20 KNOTS GUSTING TO 20-30 KNOTS ARE
POSSIBLE ACROSS THE ENTIRE FORECAST AREA DURING THE DAY SUNDAY.
THE HIGHER SPEEDS ARE RESERVED FOR LOCATION ALONG THE BLUE RIDGE.
CONFIDENCE IS FAIRLY HIGH WITH IFR CONDITIONS REMAINING THROUGH
THE FIRST 3-6 HOURS OF THE TAF PERIOD. MEDIUM CONFIDENCE ON TIMING
OF IMPROVING CONDITIONS THROUGH 12Z SUN. HIGH CONFIDENCE IN WIND
DIRECTION AND SPEED DURING THE PERIOD.
HIGH PRESSURE EXPECTED TO BUILD INTO THE REGION FROM THE WEST
MONDAY...ALLOWING UPSLOPING CLOUDS TO GRADUALLY ERODE OVER THE
MOUNTAINS...BRINGING A RETURN TO VFR WEATHER WITH UNRESTRICTED
CONDITIONS...EVEN IN THE UPSLOPE AREAS...BY MIDDAY MONDAY. DRY
WEATHER WITH MAINLY VFR WEATHER IS THEN EXPECTED IN MOST AREAS
INTO MID WEEK...WITH PERHAPS THE EXCEPTION OF A PERIOD OF SOME
UPSLOPING CLOUDS WITH MVFR CEILINGS ACROSS THE WESTERN FLANKS OF
THE APPALACHIANS LATER TUESDAY INTO WEDNESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...DS
LONG TERM...RCS
AVIATION...AMS/RCS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
854 PM CST MON DEC 16 2013
.UPDATE...
NAM IS WEAKER WITH NEXT SHORTWAVE AND IS A LITTLE SLOWER WITH ONLY
A HUNDRETH OF LIQUID QPF. THE 01Z HRRR STILL HAS UP TO AN INCH OF
SNOW MOVING THROUGH DURING THE MORNING RUSH HOUR...SO WILL NOT
MAKE ANY CHANGES UNTIL THE NEW 00Z GFS AND MESO MODELS ARE IN.
&&
.AVIATION/06Z TAFS/...
MAINLY MVFR CIGS FOR MUCH OF THE NIGHT WITH SOME IFR CIGS MAINLY
OVER SOUTH CENTRAL WISCONSIN.
STILL THINKING ANOTHER QUICK ROUND OF SNOW IS POSSIBLE EARLY TO MID
TUESDAY MORNING. THOUGH THIS TIMING IS SUBJECT TO MINOR
CHANGES...CURRENT MODELS SUGGEST THE SNOW WILL REACH THE MADISON
AREA BETWEEN 11Z AND 13Z...AND THE MILWAUKEE AREA BETWEEN 12Z AND
14Z. SIMILAR TO TODAY...WILL BE A QUICK SYSTEM...WITH THE SNOW
MOVING THROUGH IN 2-3 HOURS. SOME LOWER CIGS AND IFR VSBYS WILL
BE POSSIBLE FOR A TIME ALSO...WITH GENERALLY UP TO A HALF AN INCH
TO AN INCH EXPECTED.
MVFR CIGS MAY LINGER THROUGH THE REST OF TUESDAY...WITH SOME
FLURRIES POSSIBLE IN THE AFTERNOON
&&
.PREV DISCUSSION... /ISSUED 355 PM CST MON DEC 16 2013/
TONIGHT AND TUESDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH
WIDESPREAD SNOWFALL IS JUST REACHING THE EASTERN FORECAST AREA THIS
AFTERNOON. THE SNOW WILL CONTINUE INTO LATE AFTERNOON...WINDING DOWN
FROM WEST TO EAST FROM 5 PM TO 7 PM. EXPECT VISIBILITIES OF 1 TO 2
MILES...WITH BRIEF SNOW BURSTS TAKING THEM DOWN TO 1/4 TO 1/2 MI.
SHOULD SEE AROUND AN INCH MOST PLACES...AS MUCH AS 2 INCHES IN A FEW
SPOTS.
TEMPS A BIT TRICKY TONIGHT AGAIN...AS WINDS WILL BE ON THE LIGHT
SIDE AND THERE COULD BE A LITTLE CLEARING. SIMILAR TO LAST
NIGHT...COULD SEE TEMPS GO LOWER THAN THE FORECAST FOR AREAS THE
CLOUDS CLEAR OUT.
STILL THINKING ANOTHER QUICK ROUND OF SNOW IS POSSIBLE EARLY TO MID
TUESDAY MORNING. THOUGH THIS TIMING IS SUBJECT TO MINOR
CHANGES...CURRENT MODELS SUGGEST THE SNOW MAY IMPACT THE MORNING
COMMUTE. TIMING ESTIMATES HAVE THE SNOW STARTING IN THE MADISON AREA
BETWEEN 5 AM AND 7 AM...AND THE MILWAUKEE AREA BETWEEN 6 AM AND 8
AM. SIMILAR TO TODAY...THIS WILL BE A QUICK SYSTEM...WITH THE SNOW
MOVING THROUGH IN 2-3 HOURS. THERE WILL PROBABLY BE LOW VISIBILITIES
FOR A TIME ALSO. EXPECTING SOME BLOWING SNOW LATE MORNING INTO EARLY
AFTERNOON AS WINDS PICK UP BEHIND THE DEPARTING SYSTEM.
MAY SEE SOME FLURRIES IN THE AFTERNOON...WITH HIGHS ACTUALLY
APPROACHING NORMAL VALUES FOR MID DECEMBER.
SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY.
TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE MEDIUM
LIGHT WINDS AND CLEARING SKIES AS A RIDGE OF HIGH PRESSURE PASSES
OVER TUESDAY NIGHT WITH LOWS AROUND 10 ABOVE. THEN 850-700MB WARM
AIR ADVECTION BEGINS TOWARD 12Z WEDNESDAY...WITH SOUTH TO SOUTHWEST
SURFACE WINDS TRYING TO BRING WARMER AIR IN OVER THE SNOW PACK.
SHOULD SEE HIGHS AROUND 30 MID-LATE AFTERNOON.
WEDNESDAY NIGHT...FORECASTER CONFIDENCE HIGH
TEMPS COOL A BIT OVERNIGHT...MAINLY ACROSS THE NORTH BUT HOLD NEARLY
STEADY IN THE SOUTH WITH CONTINUED WARM ADVECTION REGIME. LOWS
AROUND 12Z THURSDAY IN THE MID 20S NORTH TO AROUND 30 IN THE SOUTH.
COULD SEE SOME FREEZING DRIZZLE DEVELOP TOWARD MORNING WITH
CONTINUED WARM AIR/MOISTURE ADVECTION SATURATING LOW LEVELS FROM THE
BOTTOM UP OVERNIGHT.
THURSDAY AND THURSDAY NIGHT...FORECAST CONFIDENCE MEDIUM
STILL LOOKING AT ICING POTENTIAL FOR THURSDAY WITH SURFACE
TEMPERATURES CRITICAL TO LOCATION AND BEST CHANCE FOR ICE
ACCUMULATION POTENTIAL. CHANCE FOR DRIZZLE/FREEZING DRIZZLE 12Z TO
18Z THURSDAY THEN ISENTROPIC ADIABATIC OMEGA INCREASES DURING THE
AFTERNOON...AND PEAKS ACROSS THE CWA WITH THE LOWEST CONDENSATION
PRESSURE DEFICITS DURING THE EVENING. LACK OF MOISTURE IN THE
DENDRITE GROWTH ZONE AND MAXIMUM 1000-700 MB LAYER TEMPERATURES
ABOVE 3C ASSURING LIQUID FALLING INTO THE NEAR-SURFACE LAYER.
FAR SOUTH AND SOUTHEAST ARE THE ONLY AREAS WITH ABOVE-FREEZING
SURFACE TEMPERATURES ON THE NAM AND GFS DURING THIS CRITICAL
PERIOD...WITH THE 12Z ECMWF LIFTING THE SURFACE FREEZING LINE TO THE
NORTHERN BORDERS OF THE CWA. CANADIAN LOOKS TOO WARM GIVEN CURRENT
SNOW PACK. WILL USE A BLEND FOR TEMPERATURES. WITH LACK OF CRYSTALS
WILL HAVE JUST RAIN/FREEZING RAIN AS THE WEATHER TYPES. FORECAST
SURFACE TEMPERATURES BRINGS THE BETTER CHANCE FOR ACCUMULATING
FREEZING RAIN ROUGHLY ALONG AND NORTH OF A LONE ROCK...LODI...JUNEAU
TO SHEBOYGAN LINE. KEEP UP WITH LATER FORECASTS.
LONG TERM...FRIDAY THROUGH MONDAY. FORECAST CONFIDENCE LOW
WILL SEE SOME LINGERING LIGHT SNOW OR FLURRIES FRIDAY MORNING WITH
DEPARTING LOW WITH QUIET WEATHER FRIDAY NIGHT. THEN MID-RANGE MODELS
BRING A DEVELOPING LOW FROM THE SOUTHERN PLAINS ALONG A TRACK UP THE
OHIO RIVER VALLEY. GFS AND CANADIAN ARE FASTER AND LESS DEVELOPED
WITH THE LOW...WITH DEEPENING OF THE SURFACE LOW OCCURRING OVER WRN
PA/NY SUNDAY MORNING...WHILE THE SLOWER ECMWF DEEPENS THE LOW AS IT
TRACKS THROUGH SRN IL/IN/OH DURING THE MORNING SUNDAY. THIS SPINS
COPIOUS AMOUNTS OF MOISTURE UP TOWARD SRN WI WITH TEMPERATURE
PROFILE BRINGING DECENT ACCUMULATIONS TO THE SE HALF OF THE CWA.
VARIABILITY IN THE MODELS LESSENS CONFIDENCE...AND CONSENSUS BLEND
ONLY BRINGS CHC POPS TO THE SE BUT THIS SYSTEM WILL HAVE TO BE
WATCHED.
AVIATION/00Z TAFS/...
WIDESPREAD SNOWFALL IS JUST REACHING THE EASTERN FORECAST AREA THIS
AFTERNOON. THE SNOW WILL CONTINUE INTO LATE AFTERNOON...WINDING DOWN
FROM WEST TO EAST FROM 23Z TO 01Z. EXPECT VISIBILITIES OF 1 TO 2
SM...WITH BRIEF SNOW BURSTS TAKING VSBYS DOWN TO 1/4 TO 1/2 SM.
SHOULD SEE AROUND AN INCH MOST PLACES...AS MUCH AS 2 INCHES IN A FEW
SPOTS.
CIGS COULD IMPROVE FOR A WHILE THIS EVENING INTO TONIGHT BETWEEN
SHORTWAVES.
STILL THINKING ANOTHER QUICK ROUND OF SNOW IS POSSIBLE EARLY TO MID
TUESDAY MORNING. THOUGH THIS TIMING IS SUBJECT TO MINOR
CHANGES...CURRENT MODELS SUGGEST THE SNOW WILL REACH THE MADISON
AREA BETWEEN 11Z AND 13Z...AND THE MILWAUKEE AREA BETWEEN 12Z AND
14Z. SIMILAR TO TODAY...WILL BE A QUICK SYSTEM...WITH THE SNOW
MOVING THROUGH IN 2-3 HOURS. SOME LOWER CIGS AND VSBYS WILL BE
POSSIBLE FOR A TIME ALSO...WITH GENERALLY A HALF AN INCH TO AN INCH
EXPECTED. COULD BE SOME BLOWING SNOW LATE MORNING INTO EARLY
AFTERNOON AS WINDS PICK UP BEHIND THE DEPARTING SYSTEM.
MVFR CIGS MAY LINGER THROUGH THE REST OF TUESDAY...WITH SOME
FLURRIES POSSIBLE IN THE AFTERNOON.&&
MARINE...
WEST TO NORTHWEST WINDS WILL GET GUSTY BEHIND A DEPARTING SYSTEM
TOMORROW. EXPECT GUSTS TO 30 KNOTS MID TO LATE MORNING...WITH GUSTS
TO 25 KNOTS THEN AFTERNOON INTO EARLY EVENING. A SMALL CRAFT
ADVISORY IS THUS BEING ISSUED FOR THIS PERIOD. WAVES SHOULD STAY ON
THE LOW END DUE TO THE OFFSHORE NATURE OF THE WINDS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 8 AM TO 10 PM CST TUESDAY FOR
LMZ643>646.
&&
$$
UPDATE...HENTZ
TONIGHT/TUESDAY AND AVIATION/MARINE...DDV
TUESDAY NIGHT THROUGH MONDAY...REM
AREA FORECAST DISCUSSION
NWS ALBANY NY
458 AM EST TUE DEC 17 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM PASSING SOUTH OF THE REGION WILL BRING A
WIDESPREAD LIGHT TO MODERATE SNOWFALL TO THE AREA TODAY. THE SNOW
WILL SPREAD NORTHWARD ACROSS THE AREA DURING THIS MORNING AND IS
EXPECTED TO TAPER OFF THIS EVENING. SCATTERED SNOW SHOWERS ARE
THEN EXPECTED TONIGHT AND WEDNESDAY...ESPECIALLY ACROSS THE HIGHER
TERRAIN. A GRADUAL WARMING TREND IS THEN EXPECTED FOR THE END OF
THE WORKWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 445 AM EST...BITTER COLD REIGNS ACROSS THE REGION...WITH
WIDESPREAD TEMPS OF -10F TO -20F ACROSS THE NORTH COUNTRY...AND -5F
TO +5F ELSEWHERE.
CLOUDS ARE RAPIDLY INCREASING ACROSS SOUTHERN AREAS...WITH A
RATHER LOW DECK...WITH CIGS GENERALLY BETWEEN 3500-5000 FT AGL.
LIGHT SNOW IS CURRENTLY DEVELOPING ACROSS MUCH OF CENTRAL/EASTERN
PA AND SW NJ...AND SHOULD CONTINUE EXPANDING NE...REACHING THE SE
CATSKILLS/MID HUDSON VALLEY REGION AROUND DAYBREAK...AND THEN INTO
THE CAPITAL REGION...SCHOHARIE VALLEY...NW CT AND BERKSHIRES
BETWEEN ROUGHLY 7 AM-10 AM...AND INTO THE MOHAWK VALLEY...THE LAKE
GEORGE/SARATOGA REGION AND SOUTHERN VT BETWEEN 10 AM AND NOON.
ONCE THE SNOW STARTS...WE EXPECT PERIODS OF LIGHT TO MODERATE SNOW
TO CONTINUE THROUGH EARLY THIS EVENING...WITH TOTAL ACCUMS
GENERALLY 2-4 INCHES...EXCEPT FOR 3-6 INCHES ACROSS PORTIONS OF
THE MID HUDSON VALLEY...NW CT...BERKSHIRES...SOUTHERN VT AND SE
CATSKILLS WHERE SOME OROGRAPHIC ENHANCEMENT IS LIKELY...AND 1-3
INCHES ACROSS THE SOUTHERN ADIRONDACKS.
IT APPEARS THAT THERE WILL BE 2 MAIN BURSTS OF SNOW THROUGH
TODAY...THE FIRST ONE BEING DRIVEN MAINLY BY LOW/MID LEVEL WARM
ADVECTION...WHICH WILL BE MAINLY THIS MORNING...THEN PERHAPS THE
BEST BURST OF SNOW LATE THIS AFTERNOON INTO EARLY THIS
EVENING...DUE TO ENHANCED 850-700 FRONTOGENESIS TO THE N/NW OF AN
EMBEDDED SHORTWAVE TRANSLATING JUST S/E OF THE
REGION...INTERACTING WITH AN INCREASING INFLUX OF LOW LEVEL
MOISTURE BEING ENTRAINED INTO THE DEVELOPING STORM SYSTEM. THIS
SECOND BURST SHOULD BE GREATEST ACROSS THE GREATER CAPITAL REGION
AND SARATOGA REGION...BERKSHIRES AND SOUTHERN VT...MOST LIKELY
BETWEEN 4 PM AND 7 PM...THEREBY POTENTIALLY ADVERSELY IMPACTING
THE EVENING COMMUTE. WE WILL HAVE TO CLOSELY MONITOR RADAR TRENDS
DURING THIS PERIOD...AS THE ENHANCED F-GEN NOTED ON THE RUC13 FROM
THE CAPITAL REGION EAST INTO THE BERKSHIRES AND SOUTHERN VT
COINCIDES WITH INCREASING MOISTURE/TO NEAR SATURATION/FROM THE
ATLANTIC WITHIN THE 850-700 LAYER...POTENTIALLY ENHANCING BANDING
POTENTIAL AND PERHAPS LEADING TO LOCALLY GREATER SNOWFALL AMTS
THAN CURRENTLY INDICATED.
SINCE NEAR TERM MODELS SUCH AS THE RUC13 AND HRRR HINT AT THIS
SECOND BURST OF SNOW BETWEEN 4 PM AND 7 PM...HAVE EXTENDED THE
WINTER WEATHER ADVISORIES UNTIL 7 PM.
TEMPS TODAY WILL STRUGGLE TO CLIMB INTO AND THROUGH THE TEENS TO
LOWER 20S IN VALLEY AREAS...AND LOWER TO MID TEENS ACROSS HIGHER
ELEVATIONS...WITH MAX TEMPS LIKELY NOT OCCURRING UNTIL BETWEEN 5-7
PM. GIVEN THAT THE CLOUDS WILL BE RATHER LOW...AND THAT MUCH OF
THE PRECIP WILL BE FALLING FROM A LOWER CLOUD DECK INITIALLY THEN
WHAT OCCURRED ON SATURDAY...THE POTENTIAL AND DEPTH OF WET BULB
COOLING WILL BE LESS THAN WHAT OCCURRED THIS PAST SAT. SO...WE
HAVE SIDED WITH THE COOLER SIDE OF A MAV/MET MOS BLEND...BUT DID
NOT STRAY TOO MUCH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
TONIGHT...ANY STEADIER SNOW SHOULD TAPER OFF ACROSS SE VT EARLY.
OTHERWISE...EXPECT SCATTERED SNOW SHOWERS TO OCCUR OVERNIGHT AS
THE MID/UPPER LEVEL TROPOSPHERIC TROUGH AND COLD POOL PASS
THROUGH...WITH 500 MB TEMPS DIPPING INTO THE -35C TO -40C RANGE.
925-700 LAPSE RATES STEEPEN...AND SHOULD ENOUGH MOISTURE BE
PRESENT WITHIN THIS LAYER...COULD LEAD TO SOME EMBEDDED HEAVIER SNOW
SHOWERS AND/OR SQUALLS...LEAVING ADDITIONAL COATINGS...TO PERHAPS
UP TO AN INCH OF SNOWFALL OVERNIGHT. TEMPS SHOULD FALL INTO THE
TEENS IN MOST AREAS.
WED-WED NT...THE AFOREMENTIONED MID LEVEL TROUGH/COLD POOL MOVES E
OF THE REGION IN THE AFTERNOON. HOWEVER...A FAIRLY WELL ALIGNED
WESTERLY FLOW MAY ALLOW FOR LAKE EFFECT SNOWBANDS TO DEVELOP
ACROSS NORTHERN HERKIMER CO IN THE AFTERNOON...AND MAY EXTEND WELL
INTO HAMILTON CO OR EVEN NW WARREN CO FOR A BRIEF TIME LATE IN THE
AFTERNOON INTO EARLY WED NT...AS SUGGESTED PER THE CSTAR FUNDED
INLAND LAKE EXTENT PROGRAM. THIS COULD LEAD TO AT LEAST 1-3 INCHES
OF SNOWFALL...WITH SOME POTENTIAL FOR GREATER AMTS...PERHAPS INTO
THE ADVISORY RANGE. WILL ADDRESS THIS POTENTIAL IN THE HWOALY.
ELSEWHERE...SCATTERED SNOW SHOWERS AND FLURRIES WILL BE POSSIBLE
ACROSS HIGHER ELEVATIONS...WHERE ADDITIONAL MINOR ACCUMS COULD
OCCUR...WITH SOME SNOW SHOWERS/FLURRIES OCCASIONALLY MIGRATING
INTO VALLEY AREAS...ESP NEAR AND N OF THE MOHAWK RIVER. FOR
TEMPS...EXPECT SLIGHTLY MILDER MAX TEMPS WED...REACHING THE 20S TO
LOWER 30S IN VALLEYS...WITH TEENS TO MID 20S ACROSS HIGHER
ELEVATIONS...AND OVERNIGHT MINS WED NT/THU AM FALLING MAINLY INTO
THE TEENS...WITH SOME SINGLE DIGITS POSSIBLE ACROSS NORTHERN AREAS
AND HIGHER ELEVATIONS ACROSS WESTERN NEW ENGLAND.
THU-THU NT...A SOUTHWEST LOW LEVEL FLOW WILL DEVELOP DURING THIS
TIME...ALLOWING FOR GRADUAL MODERATION IN TEMPS. SOME LINGERING
LAKE EFFECT SNOW MAY OCCUR THU ACROSS EXTREME NORTHERN
HERKIMER/HAMILTON COS...BEFORE THE INVERSION LEVEL FALLS.
THEN...SOME WARM ADVECTION PRECIP COULD DEVELOP ACROSS THE WESTERN
DACKS LATE THU NT...IN THE FORM OF LIGHT SNOW...OR EVEN A LIGHT
WINTRY MIX. THU MAX TEMPS SHOULD REACH THE LOWER/MID 30S IN
VALLEYS...AND 20S ACROSS HIGHER ELEVATIONS...WITH OVERNIGHT MINS
THU NT/FRI AM ONLY FALLING INTO THE 20S IN MOST AREAS...WITH TEMPS
POSSIBLY RISING IN SOME AREAS LATE AT NIGHT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
INCREASING AGREEMENT IN THE MODEL AND ENSEMBLE GUIDANCE THROUGH THE
PERIOD. ONE UPPER IMPULSE AND ASSOCIATED FORCING SUPPORTS
PRECIPITATION FRIDAY AND FRIDAY NIGHT. THEN ANOTHER UPPER IMPULSE
AND ASSOCIATED FORCING AFFECTS OUR REGION SATURDAY NIGHT THROUGH
SUNDAY NIGHT. THE TIMING OF THESE SYSTEMS WILL LIKELY GET ADJUSTED
WITH TIME AS THEY ARE WITHIN QUICK WEST SOUTHWEST UPPER CONFLUENT
STEERING FLOW. ALSO...WORDING RAIN AND SNOW THROUGH THE PERIOD SINCE
THERE IS SUCH HIGH UNCERTAINTY IN THE POTENTIAL AREAS OF SLEET
AND/OR FREEZING RAIN.
THE PRECIPITATION TYPES AND THE POSITION OF A POTENTIALLY BROAD
PRECIPITATION TRANSITION ZONE ARE STILL IN QUESTION. HOWEVER...
THERE IS MORE AGREEMENT FOR ANY MIXED PRECIPITATION EARLY FRIDAY
MORNING TO CHANGE TO MAINLY LIQUID PRECIPITATION OVER CENTRAL AND
SOUTHERN AREAS BEFORE COVERAGE OF PRECIPITATION DECREASES FRIDAY
NIGHT. MIXED PRECIPITATION COULD REMAIN MIXED OVER NORTHERN AREAS.
HIGHS FRIDAY IN THE LOWER TO MID 40S IN MANY AREAS WITH MID TO UPPER
30S IN THE HIGHER ELEVATIONS.
LOW LEVEL FORCING WEAKENS FRIDAY NIGHT AND SATURDAY WITH WEAK LOW
LEVEL RIDGING OVER THE REGION. LINGERING MOISTURE AND PROXIMITY TO
THE LOW LEVEL THERMAL GRADIENT AND WIND CONVERGENCE PROXIMATE TO THE
LOW LEVEL BOUNDARY COULD SUPPORT SCATTERED SHOWERS...WITH SOME
FLURRIES OR SNOW SHOWERS. THE BRIEF LOW LEVEL RIDGING COULD ALLOW
TEMPERATURES TO FALL TO NEAR FREEZING IN MANY AREAS FRIDAY NIGHT AND
MID TO UPPER 20S IN THE HIGHER ELEVATIONS... AGAIN SUPPORTING
SCATTERED SHOWERS AND SNOW SHOWERS.
CURRENT GUIDANCE SUGGESTS THE NEXT SYSTEM ARRIVES THROUGH THE DAY
SATURDAY AN CONTINUES SATURDAY NIGHT THROUGH SUNDAY...EXITING SUNDAY
NIGHT. THE WARM ADVECTION AND FORCING LOOK STRONGER WITH THIS
SYSTEM...DRIVING THE WARM AIR FURTHER NORTH...SUPPORTING A
PRECIPITATION TRANSITION TO RAIN IN MOST AREAS. QUITE A STRONG
SOUTHWEST TO WEST SOUTHWEST BOUNDARY LAYER JET TRACKS THROUGH THE
REGION AND THE BOUNDARY LAYER THERMAL GRADIENT IS QUITE TIGHT AS IT
TRACKS EAST AND SOUTH SUNDAY AND SUNDAY NIGHT. SO...WILL HAVE TO
KEEP AN EYE ON WINDS AND POTENTIAL FOR LOCALLY HEAVY RAIN ON THE
MELTING SNOW PACK. HIGHS SATURDAY IN THE LOWER TO MID 40S...LOWER
TO MID 30S HIGHER ELEVATIONS. HIGHS SUNDAY IN THE UPPER 40S TO LOWER
50S...WITH UPPER 30S TO LOWER 40S IN HIGHER ELEVATIONS.
STRONG COLD ADVECTION SPREADS ACROSS THE REGION BY MONDAY MORNING
AND CONTINUES THROUGH THE DAY. SOME LAKE EFFECT SNOW BANDS SHOULD
FORM BUT INLAND EXTENT IS IN QUESTION. HIGHS MONDAY IN THE 20S TO
LOWER 30S.
THERE COULD STILL BE A LOT OF CHANGES TO HOW THESE SYSTEMS DEVELOP
AND IMPACT THE REGION. THERE ARE INDICATIONS OF A POTENTIAL BROAD
MIXED PRECIPITATION TRANSITION ZONE...BUT THE POSITION AND AREAL
EXTENT OF THE PRECIPITATION TRANSITION ZONE KEEPS CHANGING IN
SUCCESSIVE SETS OF GUIDANCE. THERE IS STILL A CHANCE THAT THE
CURRENT INDICATIONS OF MORE RAIN AND LESS WINTERY PRECIPITATION OVER
MUCH OF OUR REGION COULD CHANGE BACK TO COLDER AND MORE MIXED
PRECIPITATION DEPENDING ON HOW THE SYSTEMS DEVELOP IN THE NEXT 3+
DAYS. HOWEVER...THE INCREASING CONSENSUS FROM GUIDANCE OF MORE
LIQUID AND LESS MIXED PRECIPITATION SEEMS THE MOST LIKELY SCENARIO
AT THIS TIME.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL SHIFT EASTWARD ACROSS THE THROUGH THE EARLY
MORNING HOURS. A LOW PRESSURE SYSTEM WILL BRING A WIDESPREAD LIGHT
TO MODERATE SNOWFALL TO THE AREA TODAY. THE SNOW WILL SPREAD
NORTHWARD ACROSS THE AREA DURING THE MORNING AND IS EXPECTED TO
TAPER OFF BY LATE AFTERNOON.
EXPECTING VFR CONDITIONS TO PREVAIL THROUGH THE EARLY MORNING HOURS.
CLOUDS WILL STREAM IN TOWARD SUNRISE...THICKENING AND LOWERING
QUICKLY THROUGH THE MORNING AS THE WARM ADVECTION SNOWFALL MOVES IN.
SNOW IS EXPECTED TO COMMENCE AT KPOU AROUND SUNRISE AND SPREAD
NORTHWARD TO KALB AND KPSF BY MID MORNING AND BY KGFL BY LATE
MORNING. INITIALLY MVFR CONDITIONS ARE EXPECTED WITH IFR DEVELOPING
AS THE SNOW BECOMES STEADIER AS THE MORNING PROGRESSES. AROUND 5
HOURS OF IFR SNOWS ARE EXPECTED WITH AN IMPROVE BACK TO MVFR MID TO
LATE AFTERNOON.
WINDS WILL BE NEARLY CALM THROUGH THE EARLY MORNING HOURS WITH A
LIGHT SOUTHEASTERLY FLOW DEVELOPING LATER IN THE MORNING AND
BECOMING VARIABLE AGAIN BY LATE AFTERNOON AND EVENING.
OUTLOOK...
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. SCATTERED SHRA...SHSN.
SATURDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
&&
.HYDROLOGY...
A CLIPPER TYPE SYSTEM WILL AFFECT THE REGION TODAY INTO THIS
EVENING. THE PRECIPITATION IS EXPECTED TO BE ALL SNOW WITH THIS
SYSTEM. TOTAL LIQUID EQUIVALENT WITH THIS SYSTEM IS EXPECTED TO
RANGE FROM ONE TO THREE TENTHS OF AN INCH WITH THE HIGHEST AMOUNTS
OVER THE ERN CATSKILLS...W-CNTRL MOHAWK VALLEY...AND WRN NEW
ENGLAND. THIS SYSTEM WILL REDEVELOP SOUTH OF LONG ISLAND...AND
QUICKLY MOVE NORTHEAST OF CAPE COD TOMORROW NIGHT.
SOME LAKE EFFECT SNOW IS POSSIBLE WED-THU WITH LIGHT SNOW
AMOUNTS...AND LIQUID EQUIVALENTS GENERALLY LESS THAN A TENTH OF AN
INCH FOR THE WRN DACKS REGION...AND NRN TIER OF THE HSA.
FOR THE MID WEEK...TEMPS WILL CONTINUE TO BE BELOW NORMAL AND ICE
WILL CONTINUE TO FORM AND THICKEN ON AREA RIVERS...STREAMS AND
PARTICULARLY LAKES.
A MODERATING TREND IN TEMPS IS LIKELY THU INTO FRI...WITH A
FRONTAL BOUNDARY BRINGING SOME SHOWERS TO CLOSE THE WORK WEEK.
SOME SNOW MELT IS LIKELY THIS WEEKEND. ALSO...A STORM SYSTEM
MOVING ALONG A FRONTAL BOUNDARY NEAR THE HSA MAY BRING SIGNIFICANT
PCPN TO THE FORECAST AREA SAT NIGHT INTO SUNDAY WITH EVEN MILDER
TEMPS. THIS WILL CONTINUE TO BE MONITORED FOR THE UPCOMING
WEEKEND.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR CTZ001-
013.
NY...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ054-
058>061-063>066.
MA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MAZ001-
025.
VT...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
VTZ013>015.
&&
$$
SYNOPSIS...KL/WASULA
NEAR TERM...KL
SHORT TERM...KL
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...KL/WASULA
Area Forecast Discussion
National Weather Service Lincoln IL
355 AM CST Tue Dec 17 2013
.DISCUSSION...
ISSUED 333 AM CST Tue Dec 17 2013
Weak high pressure over much of the center of the country and
edging into the Midwest in the wake of an exiting clipper system.
West/northwesterly flow aloft slowly modifying to more
southwesterly through the 7 day forecast. Brief showers coming to
an end this morning over SW ILX. First problem with the forecast
is the potential for fog tonight as the winds come around to more
swrly and push warmer and higher RH air in over the snow pack. WAA
being countered by the snow on the ground and not handled well in
the models. GFS and ECMWF getting far more continuity with each
run with respect to the initial front, but the timing of the main
storm system for the weekend as energy ejects out of the SW along
the boundary is nowhere near consistent. Thermal profiles btwn the
GFS and the ECMWF still making precip type an issue. Though first
glance at the models point to a major snow event, too much warm
air moving into the midlevels pushing the threat to more of a
potential freezing rain event. Not too many changes to the
forecast from the 12z run.
SHORT TERM...Today and Tomorrow...
Cold and cloudy conditions continue as another clipper pulls away from
the region. High pressure building into the Midwest, and winds
slowly becoming more southwesterly this evening. Temperatures
modifying, and concern for fog in the overnight as any melting is
only going to enhance RH in the boundary layer. Lack of clouds
tonight and certainly a brief pd of light winds will only add to
the threat. Same story for tomorrow as the WAA fights with
existing snow field to bring max temps up a couple degrees.
Overnight, the fog threat continues. This may be a recurring theme
through the end of the week if the snow field remains.
LONG TERM...Thursday through Monday...
Low confidence continues with the temperatures through the end of
the week. Will depend greatly on the persistence of the snow. After
the main trof pulls to the east, more southwesterly flow sets
in as a deep trof develops over the swrn CONUS. Deep upper low
now remaining open and more diffuse in the GFS and ECMWF as the models
continue to converge. SWrly flow putting ILX in a transition zone
temperature wise with the initial passage of the front on Thurs
night/Friday. Front moving into and stalling out just to the south
over the Ohio River Valley. Location of the boundary as a series
of upper waves eject out and along said front will make a major
difference on the forecast. Northerly extent of the precip with
respect to the front is the main issue for the forecast as well as
how deep into the cold air the precip reaches. Latest ECMWF still
maintaining ice as the cold air takes a little longer to move in
and midlevels remain warm. GFS still looks like mostly snow after
a transitional mix. Precip type is still ambiguous, timing is all
over the place btwn the two models into the extended. In addition
to all the mentioned problems, growing concern for the projected rapid
development of the surface system with an open wave aloft. The
confidence in the model performance is lacking considering the
dynamics look a bit off.
HJS
&&
.AVIATION...
ISSUED 1152 PM CST Mon Dec 16 2013
A very challenging aviation forecast for the next 12-18 hours.
The first thing to consider are the IFR/LIFR ceilings over the
area which were slowly moving from west to east, but has come to a
creeping halt. The short range models (NAM, HRRR and GFS) are of
very little to no help as they do not have much of a handle on the
current situation much less the forecast. With a lot of mid and
upper level clouds over the stratus deck I don`t expect the lower
clouds to move out very quickly. Thus, took a conservative route
and kept the low clouds in the TAFS through at least daybreak. In
eastern Illinois will keep the low ceilings around until late
morning (15-16Z).
The next in the series of northwest flow shortwaves is currently
in southern Manitoba and expected to drop toward the Upper
Midwest between 12Z and 18Z. Again, the models are all over the
place with the light snow. Prefer persistence in keeping a few
flurries as vicinity showers in the TAFs along the I-74 corridor.
After this last shortwave swings through the region we should
finally see clearing by late evening as subsidence develops. Kept
fog out of the forecast for now since the prevailing winds
tomorrow evening should be westerly at 6-10 kts.
Miller
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
329 AM CST TUE DEC 17 2013
.DISCUSSION...
328 AM CST
TODAY...
MAIN CONCERNS WILL BE FOCUSED ON THE MID-LVL WAVE THAT IS QUICKLY
SLIDING EAST ACROSS THE WESTERN GREAT LAKES...POSSIBLY BRINGING A
SLUG OF LGT SNOW TO NORTH/NORTHEAST IL AND NORTHWEST IN THIS MORNING
THRU MIDDAY. THEN THE POTENTIAL FOR SOME BLOWING SNOW AS THE
GRADIENT RAMPS UP MIDDAY AND MIXING JUMPS TO ARND 3KFT AGL.
IR IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS THE REGION...AND
SOME COOLING WITH CLOUD TOPS WITH THE WEAK WAVE SLIDING EAST ACROSS
WESTCENTRAL WISC EARLY THIS MORNING. KARX RADAR INDICATES AN AREA OF
RETURNS ACROSS THIS AREA...HOWEVER THE RECENT COUPLE OF HOURS HAVE
INDICATED SOME DOWNWARD TREND IN THE SOUTHERN PORTION OF THIS
PRECIP. SFC OBS ARE NOT INDICATING ANY SNOW IN FAR SOUTHEAST MN AND
HAS TENDED TO BE FOCUSED FURTHER NORTH. BASED ON CURRENT
TRAJECTORY...THE BEST LGT SNOW MAY END UP HOLDING FURTHER NORTH INTO
WISC. BUFR PROFILES HAVE BACKED OFF ON THE OMEGA PLACEMENT...HOWEVER
A HANDFUL OF POINTS CONTINUE TO INDICATE SOME DEGREE OF LIFT THROUGH
THE FAVORED DGZ ARND 12-15Z. DPROG/DT OF THE BUFR SITES ALSO
INDICATES A DOWNWARD TREND...SUPPORTING THE LOWER CONFIDENCE IN SNOW
TOTALS. THE CAVEAT AND CHALLENGE IS THE NARROW CHANNEL OF MOISTURE
THAT STRETCHES WEST AND RECENT RAP GUIDANCE HAS INDICATED AN
ENHANCEMENT TO THIS FEATURE AS IT PIVOTS EAST ACROSS THE CWFA THIS
MORNING.
SNOWFALL RATIOS SHOULD FALL AROUND 20:1...SO RATHER DRY.
BASED ON COBB OUTPUT FROM THESE PROFILES SNOWFALL SHUD GENERALLY
FALL BETWEEN A FEW TENTHS TO 1". COULD SEE AREAS CLOSEST TO THE
WISCONSIN STATELINE PICKING UP SLIGHTLY MORE OR WITHIN A 1-2" RANGE.
THE WAVE WILL REMAIN PROGRESSIVE AND SHUD COME TO AN END BY 15-17Z
FROM WEST TO EAST...AS WIND GUSTS BEGIN TO DEVELOP. ANY FRESH
SNOWFALL SHUD EASILY BLOW AROUND. THIS MAY BE MORE FOCUSED ACROSS
AREAS NORTH OF I-80...AS THE PATCHY DZ EARLY THIS MORNING WILL
MOISTEN UP THE SNOW FURTHER SOUTH AND LIMIT THE ABILITY FOR THE SNOW
TO BLOW AROUND.
TEMPS WILL BEGIN TO REBOUND TDY...AS THE 500MB TROUGH AXIS BEGINS TO
PUSH EAST OF THE WESTERN GREAT LAKES. TEMPS WILL STEADILY WARM INTO
THE UPR 20S TO ARND 30 ACROSS THE SOUTHERN CWFA.
CONFIDENCE IN SNOWFALL...MEDIUM/LOW.
CONFIDENCE IN TEMPS...HIGH.
TONIGHT THROUGH WEDNESDAY...
500MB HEIGHTS BEGIN TO RISE THIS EVENING WITH DIFFLUENT FLOW LIFTING
NORTH FROM THE SFC RIDGE CENTERED ACROSS THE OZARKS. THIS SHUD AID
IN ERODING SOME OF THE CLOUD COVER...AND COULD SEE P-CLOUDY SKIES
FOR A BRIEF PERIOD OVERNIGHT. THEN ANOTHER WEAK MID-LVL WAVE IS
PROGGED TO BUMP INTO THE DIFFLUENT FLOW AND BRING SOME MID-LVL
MOISTURE AND CLOUDS BACK TO THE AREA DURING THE OVERNIGHT HOURS.
500MB FLOW CONTINUES TO EVOLVE INTO A ZONAL SETUP...ALTHOUGH THIS
WILL ONLY BE TEMPORARY THRU WED. SFC RIDGE ACROSS THE OZARKS DRIFTS
EAST TOWARDS THE MID-ATLANTIC/GULF STATES...WITH LLVL FLOW TURNING
SOUTH/SOUTHWEST FOR THE CWFA.
FOR THE FIRST TIME IN SEVERAL DAYS WED MAY SEE THE 850MB 0 DEG
ISOTHERM LIFT OVERHEAD ALONG THE LEADING EDGE OF INCREASED WARM AIR
ADVECTION. THE MID-LVL THERMAL RIDGE CONTINUES TO WARM FURTHER SOUTH
WITH TEMPS RISING TO NEAR 9 DEG C OVER NORTHERN MISSOURI WED AFTN.
GIVEN THE EXPANSIVE SNOW COVER...THE CHALLENGE IS HOW WARM WILL WED
END UP BECOMING. GUIDANCE HAS TRENDED SLIGHTLY COOLER OVER THE PAST
FEW DAYS WITH WED HIGHS. AT THIS TIME THE GENERAL CONSENSUS HAS BEEN
ON TEMPS IN THE LOW 30S ALONG/NORTH OF I-80 AND POINTS SOUTH
POSSIBLY REACHING THE MID 30S.
WITH DEW POINTS PROGGED TO BE RISING TO ARND FREEZING...THE SNOWMELT
RATES WILL RAMP UP. WITH THE ADDED MOISTURE COUPLED WITH A
MOISTENING MID/UPR LVLS AHEAD OF THE NEXT WEATHER SYSTEM...THE
ENVIRONMENT SEEMS PRIMED FOR THE DEVELOPMENT OF PATCHY/AREAS OF FOG.
FREQUENTLY MELTING SNOW CAN PRODUCE SHALLOW DENSE FOG...SO THIS WILL
CONTINUE TO BE THE FOCUS WED NGT.
CONFIDENCE IN TEMPS...MEDIUM.
CONFIDENCE IN FOG DEVELOPING WED NGT...HIGH.
THURSDAY THROUGH SATURDAY...
MID-LVL FLOW CONTINUES TO PROGRESS INTO A SOUTHWEST SETUP WITH A
500MB VORT MAX PUSHING INTO THE FOUR-CORNERS REGION THUR. SFC
RIDGING IN THE LLVLS WILL BE PARKED OVER THE SOUTHEASTERN
CONUS...ALLOWING FOR CONTINUED FEED OF WARM AIR ADVECTING NORTH
THROUGH THE OZARKS INTO THE OHIO VALLEY/GREAT LAKES REGIONS THUR.
GUIDANCE CONTINUES TO FEATURE A WAVE DEVELOPING ALONG THE LEE-SIDE
OF THE ROCKIES THUR...AS A WEAK SFC RIDGE SAGS SOUTH FROM CENTRAL
CANADA INTO THE UPPER MIDWEST AND SHARPENS UP A BAROCLINIC ZONE OVER
THE NORTHERN PLAINS STRETCHING NORTHEAST THROUGH THE UPPER PENINSULA
OF MICHIGNA. THIS WILL LIKELY KEEP THE WARM AIR OVER THE CWFA
THUR...AND ANY PRECIP WILL LIKELY FALL AS LIQUID THUR. AT THE ONSET
THUR MORNING A BRIEF PERIOD OF FZDZ/FZRA MAY OCCUR...HOWEVER THIS
WILL LIKELY BE BRIEF. GUIDANCE HAS TRENDED SLIGHTLY FURTHER SOUTH
WITH THE SFC LOW FOR THUR NIGHT...AS THE 850MB LOW IS PROGGED TO
SLIDE OVER SOUTHCENTRAL WISC.
WITH SOME DEGREE OF UNCERTAINTY REMAINING IN THE PLACEMENT OF THE
SFC LOW...THIS OPENS UP DECREASED CONFIDENCE IN HIGH TEMPS FOR THUR.
A FURTHER NORTH PATH WOULD PROVIDE TEMPS IN THE MID/UPR
30S...MEANWHILE A CORRECTION TO THE SOUTH WOULD KEEP TEMPS ARND 30
TO LOW 30S. FURTHER COMPOUNDING THIS WOULD BE THE THEN POTENTIAL FOR
P-TYPE ISSUES.
THE SFC RIDGE ACROSS THE UPPER MIDWEST SHUD HELP TO PUSH THE
BAROCLINIC BOUNDARY SOUTH FOR FRI...AS THE LOW LIFTS NORTHEAST OF
THE FORECAST AREA. THIS SHUD AID IN COOLER AIR FILTERING IN BEHIND
AND PUSHING DEW POINTS BACK INTO THE 20S. P-TYPE FOR FRI SHUD BE
LIMITED TO RA/SN...AND TRANSITION TO ALL SN BY FRI AFTN/EVE.
500MB VORT MAX ACROSS THE FAR SOUTHWEST CONUS WILL BEGIN TO DIG
SOUTHEAST OF NEW MEXICO...WHICH WILL LIKELY TRANSLATE IN THE
DOWNSTREAM BOUNDARY SAGGING FURTHER SOUTH THROUGH THE OHIO VALLEY
FRI NGT. THEN YET ANOTHER WAVE IS PROGGED TO DEVELOP ACROSS EASTERN
TEXAS AND TAKE A CLASSIC TRAJECTORY TOWARDS THE OHIO VALLEY FOR THE
SECOND HALF OF THE WEEKEND.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
SUNDAY THROUGH EARLY CHRISTMAS WEEK...
ENSEMBLES INDICATE A SIMILAR COLD SETUP FOR THE SECOND HALF OF THE
WEEKEND INTO EARLY CHRISTMAS WEEK. WESTERN MID-LVL RIDGE MAY BEGIN
TO AMPLIFY FOR EARLY NEXT WEEK...RESULTING IN A DOWNSTREAM TROUGH
POSITIONED OVER THE GREAT LAKES REGION. OPERATIONAL SOLUTIONS
CONTINUE TO POINT TOWARDS A ROBUST WEATHER SYSTEM SUN LIFTING
NORTHEAST ACROSS THE REGION FROM THE SOUTHERN PLAINS/EASTERN
TEXAS...WITH TEMPS COLD ENOUGH TO SUPPORT ALL SNOW FOR THIS EVENT.
THEN ON THE BACKSIDE OF THIS MUCH COLDER AIR POURS BACK INTO THE
CWFA WITH TEMPS ALOFT RETURNING TO -10 TO -14 DEG C AT 850MB FOR
EARLY CHRISTMAS WEEK. THIS WILL KEEP SFC TEMPS IN THE UPPER TEENS TO
LOW 20S.
CONFIDENCE IN SUNDAY SYSTEM...HIGH.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* IFR CIGS WITH PERIODS OF MVFR VSBY ARE EXPECTED UNTIL THE SNOW
STARTS.
* SNOW RETURNS ARND 13Z WITH VSBY DROPPING TO AROUND A MILE. BRIEF
REDUCTIONS TO BELOW 1 SM PSBL.
* STRONG WEST WINDS SET UP LATE IN THE MORNING THROUGH THE
AFTN...20 KT GUSTING TO ARND 30 KT.
JEE
//DISCUSSION...UPDATED 06Z...
A LOW PRESSURE TROUGH IS OVER THE REGION WITH THE PARENT LOW OVER
SOUTH CENTRAL CANADA. ANOTHER UPPER LEVEL WAVE WILL APPROACH FROM
THE NW EARLY THIS MORNING KICKING OFF MORE SNOW. CIGS ARE
CURRENTLY MVFR WITH THE ONLY IFR SITES BEING RFD AND GYY. NOT SURE
HOW THE WIDESPREAD IFR CIGS WEST AND SOUTH OF THE TERMINALS ARE
STAYING OUT OF THE TERMINALS...BUT BETTING NO ONE IS COMPLAINING.
WHILE THE OBS ARE NOT SHOWING IFR...KEPT THE TEMPOS GOING WITH IFR
THROUGH THE MORNING. VSBYS HAVE ALSO COME UP WITH THE FOG
REMAINING ALSO TO THE SOUTH AND WEST OF THE TERMINALS. THIS IS
PROBABLY DUE TO THE SLIGHTLY DRIER AIR OVER THE TERMINALS.
WEST WINDS WILL PICK UP AS THE GRADIENT TIGHTENS...SO THINKING ALL
SITES OTHER THAN RFD SHOULD REMAIN VFR OVERNIGHT. THE SNOW ARRIVES
AROUND DAYBREAK AT RFD AND IT SHOULD BE ANOTHER QUICK SYSTEM.
FORCING LOOKS DECENT IN THE SNOW GROWTH ZONE...SO THINKING 1 1/2SM
IS STILL REASONABLE. MAY SEE A BRIEF PERIOD OF HEAVIER AND LESS
THAN 1 SM VSBY...BUT NOT ENTIRELY SURE WHERE IN THE SNOW WINDOW
THIS WOULD OCCUR. WILL LIKELY ADD A TEMPO FOR REDUCED VSBY LATER.
WINDS REALLY RAMP UP BY MID MORNING WITH GUSTS ARND 30 KT
EXPECTED. THE ADDED MIXING WILL HELP LIFT CIGS TO VFR WITH VFR
CONDITIONS EXPECTED FOR THE REST OF THE PERIOD. GUSTS DIMINISH IN
THE AFTN WITH WINDS BCMG SW BY WEDNESDAY MORNING.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM-LOW CONFIDENCE IN HOW LONG CURRENT IFR CIGS AND MVFR VSBY
WILL PERSIST.
* HIGH CONFIDENCE IN SNOW OCCURRING.
* MEDIUM CONFIDENCE ON HOW LOW VSBY WILL GET WITH SNOW.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN W/ FOG.
FRIDAY...CHANCE OF RAIN OR SNOW BECOMING ALL SNOW BY THE
AFTERNOON.
SATURDAY...CHANCE OF SNOW.
SUNDAY...CHANCE OF SNOW.
RODRIGUEZ
&&
.MARINE...
306 AM CST
FIRST OF ALL MADE NO CHANGES TO THE ONGOING HEADLINES AS THEY ALL
SEEM ON TRACK. A SMALL CRAFT ADVISORY WILL BE NEEDED FOR THE INDIANA
NEARSHORE WATERS AFTER THE GALE WARNING DUE TO LINGERING HAZARDOUS
WAVES.
LOW PRESSURE IS OVER ONTARIO AND IT WILL SLIDE TO THE EAST
TODAY...WHILE ITS COLD FRONT PASSES OVER THE LAKE THIS AFTERNOON.
AT THE SAME TIME HIGH PRESSURE BUILDS OVER THE CENTRAL PLAINS. THIS
WILL TIGHTEN THE PRESSURE GRADIENT OVER THE SOUTHERN END OF THE
LAKE...RESULTING IN LOW END GALES FORMING THIS MORNING THROUGH EARLY
THIS EVENING. WEST WINDS DIMINISH TO ARND 20 KT BY WEDNESDAY
MORNING AS HIGH PRESSURE PASSES TO THE SOUTH. WINDS PICK BACK UP ON
THE BACKSIDE OF THE HIGH LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING. A BRIEF PERIOD OF SW GALES TO 35 KT IS POSSIBLE DURING
THAT TIME. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED AS WELL FOR
WEDNESDAY AFTERNOON AND EVENING. WINDS WEAKEN WEDNESDAY NIGHT AS A
TROUGH OF LOW PRESSURE SITS OVER THE LAKE WEDNESDAY NIGHT THROUGH
THURSDAY. THE NEXT WEAK LOW MOVES OVER THE LAKE THURSDAY NIGHT
BEFORE SHIFTING EAST ON FRIDAY. WINDS TURN LIGHT AND VARIABLE
BEHIND THE LOW ON SATURDAY...BUT THEN TURN NORTH AND STRENGTHEN
SATURDAY NIGHT INTO SUNDAY IN RESPONSE TO THE NEXT SYSTEM. GUIDANCE
FEATURES ANOTHER LOW PUSHING UP THE OHIO RIVER VALLEY SATURDAY NIGHT
INTO SUNDAY WITH HIGH PRESSURE BUILDING DOWN THE PLAINS.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM TUESDAY TO 9 PM TUESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...9 AM
TUESDAY TO MIDNIGHT WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
309 AM CST TUE DEC 17 2013
.DISCUSSION...
830 PM CST
CHARACTERISTIC OF THIS YOUNG 2013-2014 WINTER...ONE WEATHER ISSUE
DEPARTS AND ANOTHER QUICKLY FOLLOWS ON ITS HEELS. NOT ONLY IS THAT
NEXT ISSUE THE BRIEF SHOT OF SNOW TUESDAY MORNING...BUT ALSO
FREEZING FOG FOR AREAS ALONG AND SOUTH OF HIGHWAY 24 DURING THIS
EVENING. WE ISSUED A SPECIAL WEATHER STATEMENT FOR BOTH.
GOES WATER VAPOR SATELLITE AND UPPER AIR ANALYSES INDICATE THE
SHORT WAVE OF THE EARLIER SNOW IS HEADING EAST OVER LAKE MI ON A
STRONG 80 KT 500MB JET MAX. THE MAIN PRESSURE FALLS ARE LOCATED
EVEN FURTHER NORTH ACROSS THE FAR NORTHERN GREAT LAKES...SO THE
SURFACE REFLECTION ACROSS OUR AREA HAS BEEN WEAK. THIS HAS HELPED
ALLOW FOR SATURATION IN THE LOW-LEVELS AND THE INABILITY TO ADVECT
IT AWAY. BOTH THE 00Z DVN AND ILX SOUNDINGS SHOWED STRONG
INVERSIONS OF AROUND 7C WITH NEARLY COMPLETE SATURATION BELOW.
SATELLITE AND OBSERVATIONS CORRELATE WITH THIS LOW-LEVEL MOISTURE
WELL...DEPICTING LOW VISIBILITIES ACROSS CENTRAL IL.
LAW ENFORCEMENT HAS REPORTED THIS ALONG WITH ICY ROADS IN FORD AND
BENTON COUNTIES AS TEMPERATURES ARE WELL BELOW FREEZING. ITS NOT
IMPOSSIBLE THERE IS A LITTLE DRIZZLE IN THIS MUCK AS WELL GIVEN
THE DECENT WIND FLOW AND SLIGHT ASCENT AT AND JUST ABOVE THE
INVERSION LEVEL. EVENTUALLY WESTERLY SURFACE WINDS DO INCREASE
SOME AS THE PRESSURE GRADIENT TIGHTENS OVERNIGHT. RAP AND HRRR
VISIBILITY AND CIG FORECAST DO TRY TO SHOW THE VERY LOW SATURATION
ADVECTING EAST BY EARLY OVERNIGHT AND THAT SEEMS
REASONABLE...THOUGH THEY COULD BE A LITTLE HASTY WITH THAT. GIVEN
THE SOMEWHAT LIMITED EXPECTED DURATION AND REPORTS OF VISIBILITY
NOT BEING AS LOW AS ONE QUARTER MILE IN OUR FORECAST AREA...HAVE
JUST GONE WITH AN SPS AS OPPOSED TO AN ADVISORY.
NEXT QUICK MOVING CLIPPER IS SEEN IN NW MN ON WATER VAPOR AND IS
ON A PATH FOR THE CWA BY DAYBREAK. THE GOING TIMING IN THE GRIDS
LOOKS GREAT COMPARED TO SHORT TERM/HIGH RES GUIDANCE WHICH SEEMED
TO HAVE HANDLED TODAYS SIMILAR EVENT WELL. RATIOS LOOK HIGHER WITH
THE TUE MORNING EVENT THAN TODAY...AND THE LATEST LOCAL 8KM ARW
DOES SHOW A COUPLE HOURS OF NEAR 25:1 RATIOS WHICH MAY BE A BIT
HIGH...BUT DO AT LEAST INDICATE THAT BURST POTENTIAL DURING RUSH
HOUR. TIMING AND MAGNITUDE OF WIND GUST INCREASE STILL LOOKS
REPRESENTATIVE AND THE FORECAST SPEEDS SHOULD BE ENOUGH TO
REALIZE PATCHY BLOWING OF THE FRESH SNOWFALL IN OPEN AREAS.
MTF
//PREV DISCUSSION...
305 PM CST
NUMEROUS FORECAST CONCERNS GOING THROUGH THE WEEKEND AS THE UPPER
FLOW PATTERN SHIFTS FROM FAVORING NORTHWEST FLOW AND PERIODIC
CLIPPERS TO A SOUTHWESTERLY FLOW SUPPORTING A BRIEF WARM UP FOLLOWED
BY THE POTENTIAL FOR STRONGER SOUTHWEST SYSTEMS.
EARLY AFTERNOON WATER VAPOR IMAGERY SHOWS A BROAD TROUGH OVER MOST
OF THE U.S. WITH BROAD RIDGING COMING OVER THE WEST COAST OF NORTH
AMERICA. EMBEDDED IN THE BROAD TROUGH ARE A SERIES OF WAVES...THE
FIRST OF WHICH IS ENTERING THE LOCAL AREA BRINGING BANDS OF SNOW.
THE NEXT WAVE OF NOTE IS MORE SUBTLE AS IT MOVES SOUTHEAST ACROSS
THE CENTRAL ALBERTA/SASKATCHEWAN BORDER AND GENERATES SNOW INTO
NORTHEASTERN MONTANA. THIS WAVE WILL MOVE INTO THE LOCAL AREA
TOMORROW MORNING. OTHERWISE...THE PATTERN WILL BECOME LESS AMPLIFIED
DURING MID WEEK AS THE MAIN UPPER TROUGH PUSHES EAST FOLLOWED BY THE
BROAD RIDGING CURRENTLY TO THE WEST.
TONIGHT AND TUESDAY...THE CURRENT CLIPPER WILL BE DEPARTING THE AREA
THROUGH THE EARLY EVENING HOURS BRINGING SNOW TO AN END AND TURNING
WINDS WESTERLY. ATTENTION TURNS TO THE MORE SUBTLE WAVE MOVING
SOUTHEAST ACROSS THE CENTRAL ALBERTA/SASKATCHEWAN BORDER AND A
SURFACE LOW TO THE EAST OF THE WAVE OVER MANITOBA WHICH WILL ALSO
MOVE SOUTHEAST WITH THE CENTER TRACKING INTO WESTERN ONTARIO TUESDAY
MORNING. A COLD FRONT WILL TRAIL THE LOW AND PUSH ACROSS THE LOCAL
AREA DURING THE MORNING. ANOTHER ROUND OF SNOW WILL LIKELY ACCOMPANY
THE PASSAGE OF THE UPPER WAVE AND SURFACE COLD FRONT. GUIDANCE
CONTINUES TO SHOW A RANGE OF SOLUTIONS WITH THE EXTENT/AMOUNT OF THE
PRECIP ACROSS THE AREA BUT GENERALLY HAS BEEN MORE BULLISH WITH
SNOWFALL COVERAGE OVER THE AREA THAN EARLIER RUNS. THIS FALLS IN
LINE WITH THE OBSERVED TRENDS OF THE CLIPPER LAST NIGHT AND THE ONE
CURRENTLY CROSSING THE AREA AND SEE LITTLE TO SUPPORT HAVING
DIFFERENT EXPECTATIONS FOR THIS NEXT ONE. WILL CONTINUE WITH THE
HIGH POPS ACROSS THE NORTHERN QUARTER TO THIRD OF THE AREA...WITH
THE FOCUS FOR MOST INTENSE AND LONGEST DURATION OF SNOW ALONG AND
NORTH OF A ROCKFORD TO CHICAGO TO VALPARAISO LINE...WHILE LIGHTER
SNOW FALLS TO THE SOUTH OF THIS LINE. THE UPPER WAVE LOOKS TO BE
SLIGHTLY WEAKER THAN THE ONE CURRENTLY CROSSING THE AREA BUT DOES
LOOK TO STRENGTHEN A BIT AS IT APPROACHES IN CONJUNCTION WITH A
BETTER ALIGNMENT OF THE LEFT EXIT OF AN UPPER JET. MODEL GUIDANCE
SHOWS A RANGE OF SNOWFALL AMOUNTS FROM VERY LITTLE TO A FEW INCHES
AND EVEN DIFFERS IN THE MAGNITUDE OF FORCING RELATIVE TO THE FAVORED
CRYSTAL GROWTH REGION. AT THIS POINT FEEL THE BEST ROUTE IS TO STICK
WITH THE OBSERVED TRENDS OF RECENT CLIPPERS AND ACCOUNT FOR THE
EXPECTATION OF SOME BETTER ORGANIZATION OF THE UPPER WAVE AND
FAVORED JET PLACEMENT. WITH THIS IN MIND FEEL THAT IT IS LIKELY THAT
NORTHERN PORTIONS OF THE AREA WILL SEE ANOTHER 1 TO POSSIBLY 2 INCH
EVENT WITH HIGH SNOW RATIOS. STEEP MID LEVEL LAPSE RATES AND GOOD
FORCING IN THE SNOW GROWTH ZONE SIMILAR TO TODAY SUPPORT
ACCUMULATION RATES OF 0.5 TO 0.75 IN/HR. CONTINUED WITH A SNOW RATIO
OF 16-18:1 OVERALL. MAY BE ABLE TO USE AMOUNTS/RATIOS/RATES FROM THE
CURRENT SNOW TO BETTER REFINE FOR THE MORNING. TIMING-WISE...SNOW
SHOULD MOVE INTO THE NORTHWEST PART OF THE AREA TOWARD DAYBREAK AND
THE CHICAGO METRO RIGHT AROUND OR JUST AFTER DAYBREAK THEN EXIT TO
THE EAST DURING THE LATE MORNING HOURS. THE PASSAGE OF THE COLD
FRONT WILL BRING A SHIFT TO NORTHWEST WINDS WHICH WILL INCREASE WITH
GUSTS PUSHING 35-40 MPH FROM LATE MORNING THROUGH THE AFTERNOON
LEADING TO BLOWING SNOW. HIGHS SHOULD BE RIGHT AROUND 30...THOUGH
THERE COULD BE A SLIGHT DECREASE IN TEMPS IN THE AFTERNOON WITH SOME
COOL ADVECTION BUT CLEARING SKIES AND SUNSHINE MAY OFFSET THIS. LOWS
TUESDAY NIGHT SHOULD FALL INTO THE MID TEENS WITH WINDS DIMINISHING
AND TURNING SOUTHWEST.
WEDNESDAY THROUGH FRIDAY...THE UPPER TROUGH CARVED OUT BY THE SERIES
OF CLIPPERS WILL SWING TO THE EAST AND OFF THE NEW ENGLAND COAST
WEDNESDAY ALLOWING FOR BROAD UPPER RIDGING TO SPREAD ACROSS THE
U.S. THIS WILL BRING A PUSH OF MID LEVEL WARM ADVECTION TO THE
REGION WEDNESDAY INTO THURSDAY WITH H85 TEMPS WARMING TO AROUND +6C
OR SO AND H92 TEMPS WARMING JUST ABOVE 0C. THIS WILL ALLOW FOR
SURFACE WARMING AS WELL BUT SNOW COVER WILL BE ONE LIMITING FACTOR.
TEMPS WEDNESDAY WILL BE TRICKY BECAUSE ASIDE FROM SOME MID LEVEL WAA
CLOUDS EARLY THERE WILL LIKELY BE AT LEAST SOME SUN AS WELL AS A
STRONG SOUTHWEST WIND. BOTH OF THESE POINT TOWARD WARMER HIGHS GIVEN
THAT THE LOWER ATMOSPHERE WILL STILL BE RELATIVELY DRY. THIS SHOULD
ALLOW MOST AREAS TO WARM TO OR JUST ABOVE FREEZING. BY THURSDAY...AN
UPPER TROUGH WILL BE WORKING INTO THE WESTERN U.S. WITH THE UPPER
FLOW SPLITTING INTO TWO STREAMS AS THE TROUGH DIGS SOUTH AND CUTS
OFF OVER OR JUST OFF THE CALIFORNIA COAST. HEIGHT FALLS AHEAD OF
THIS TROUGHING WILL LEAD TO SURFACE LOW PRESSURE DEVELOPMENT ACROSS
THE CENTRAL/SOUTHERN ROCKIES WITH AN INVERTED TROUGH AXIS EXTENDING
NORTHEAST ACROSS THE LOCAL AREA. DEEP LAYER MOISTURE WILL BE
INCREASING THURSDAY LEADING TO PRECIP CHANCES...ESPECIALLY LATER IN
THE DAY WITH LOW LEVEL MOIST ADVECTION ACTING ON THE SNOW PACK TO
LIKELY GENERATE FOG. THIS WILL PROBABLY KEEP TEMPS IN THE MID TO
UPPER 30S. PRECIP MAY END UP BEING MORE DRIZZLE THAN FALLING PRECIP
THROUGH THE DAY AND POSSIBLY THE EVENING/OVERNIGHT. THE UPPER FLOW
LOOKS TO REMAIN SPLIT WITH NORTHERN STREAM ENERGY KICKING THE
SURFACE LOW NORTHEAST RIGHT ACROSS THE AREA THURSDAY NIGHT AND
FRIDAY MORNING. THIS WILL ALSO BRING A COLD FRONT THOUGH THE AREA
EARLY FRIDAY. ANY RAIN WILL LIKELY TURN TO A MIX OR ALL SNOW FRIDAY
MORNING. OVERALL PRECIP AMOUNTS LOOK LIGHT WITH WEAK OR DISJOINTED
FORCING. HIGHS FRIDAY WILL LIKELY BE EARLY THEN FALL THROUGH THE
DAY.
SATURDAY THROUGH MONDAY...THIS PERIOD BEARS WATCHING AS ENERGY FROM
THE SOUTHERN STREAM CUTOFF UPPER LOW IS EXPECTED TO KICK NORTHEAST
THIS WEEKEND AS A REINFORCING UPPER TROUGH MOVES SOUTHEAST INTO THE
NORTHERN PLAINS. THIS WILL LIKELY SEND A SURFACE LOW AND/OR INVERTED
TROUGH NORTHEAST WITH RECENT GUIDANCE BRINGING IT SOUTHEAST OF THE
AREA. RIGHT NOW THE FAVORED TIME FOR THE SYSTEM TO BRING PRECIP TO
THE AREA WOULD BE LATER SATURDAY INTO SUNDAY. GIVEN THE PRECEDING
SHIFT IN THE UPPER FLOW TO A MORE ZONAL PATTERN AHEAD OF THE
TROUGHED FLOW...THERMAL FIELDS WILL BE MORE CRITICAL IN THAT THEY
WILL LIKELY BE WARM ENOUGH FOR A RANGE OF PRECIP TYPES TO OCCUR
DEPENDING ON WHERE THE LOW TRACKS. OVERALL SYSTEM STRENGTH AND
MOISTURE FEED SUPPORT HIGHER END PRECIP AMOUNTS WITH AFFECTED AREAS
DEPENDING ON THE TRACK. STILL VERY EARLY TO HAVE MUCH CONFIDENCE IN
DETAILS GIVEN THE EVOLUTION OF UPPER FLOW THAT NEEDS TO TAKE PLACE
IN THE MEANTIME BUT THERE LOOKS TO BE A GOOD CHANCE FOR A SYSTEM TO
BE AFFECTING THE REGION.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* IFR CIGS WITH PERIODS OF MVFR VSBY ARE EXPECTED UNTIL THE SNOW
STARTS.
* SNOW RETURNS ARND 13Z WITH VSBY DROPPING TO AROUND A MILE. BRIEF
REDUCTIONS TO BELOW 1 SM PSBL.
* STRONG WEST WINDS SET UP LATE IN THE MORNING THROUGH THE
AFTN...20 KT GUSTING TO ARND 30 KT.
JEE
//DISCUSSION...UPDATED 06Z...
A LOW PRESSURE TROUGH IS OVER THE REGION WITH THE PARENT LOW OVER
SOUTH CENTRAL CANADA. ANOTHER UPPER LEVEL WAVE WILL APPROACH FROM
THE NW EARLY THIS MORNING KICKING OFF MORE SNOW. CIGS ARE
CURRENTLY MVFR WITH THE ONLY IFR SITES BEING RFD AND GYY. NOT SURE
HOW THE WIDESPREAD IFR CIGS WEST AND SOUTH OF THE TERMINALS ARE
STAYING OUT OF THE TERMINALS...BUT BETTING NO ONE IS COMPLAINING.
WHILE THE OBS ARE NOT SHOWING IFR...KEPT THE TEMPOS GOING WITH IFR
THROUGH THE MORNING. VSBYS HAVE ALSO COME UP WITH THE FOG
REMAINING ALSO TO THE SOUTH AND WEST OF THE TERMINALS. THIS IS
PROBABLY DUE TO THE SLIGHTLY DRIER AIR OVER THE TERMINALS.
WEST WINDS WILL PICK UP AS THE GRADIENT TIGHTENS...SO THINKING ALL
SITES OTHER THAN RFD SHOULD REMAIN VFR OVERNIGHT. THE SNOW ARRIVES
AROUND DAYBREAK AT RFD AND IT SHOULD BE ANOTHER QUICK SYSTEM.
FORCING LOOKS DECENT IN THE SNOW GROWTH ZONE...SO THINKING 1 1/2SM
IS STILL REASONABLE. MAY SEE A BRIEF PERIOD OF HEAVIER AND LESS
THAN 1 SM VSBY...BUT NOT ENTIRELY SURE WHERE IN THE SNOW WINDOW
THIS WOULD OCCUR. WILL LIKELY ADD A TEMPO FOR REDUCED VSBY LATER.
WINDS REALLY RAMP UP BY MID MORNING WITH GUSTS ARND 30 KT
EXPECTED. THE ADDED MIXING WILL HELP LIFT CIGS TO VFR WITH VFR
CONDITIONS EXPECTED FOR THE REST OF THE PERIOD. GUSTS DIMINISH IN
THE AFTN WITH WINDS BCMG SW BY WEDNESDAY MORNING.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM-LOW CONFIDENCE IN HOW LONG CURRENT IFR CIGS AND MVFR VSBY
WILL PERSIST.
* HIGH CONFIDENCE IN SNOW OCCURRING.
* MEDIUM CONFIDENCE ON HOW LOW VSBY WILL GET WITH SNOW.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN W/ FOG.
FRIDAY...CHANCE OF RAIN OR SNOW BECOMING ALL SNOW BY THE
AFTERNOON.
SATURDAY...CHANCE OF SNOW.
SUNDAY...CHANCE OF SNOW.
RODRIGUEZ
&&
.MARINE...
306 AM CST
FIRST OF ALL MADE NO CHANGES TO THE ONGOING HEADLINES AS THEY ALL
SEEM ON TRACK. A SMALL CRAFT ADVISORY WILL BE NEEDED FOR THE INDIANA
NEARSHORE WATERS AFTER THE GALE WARNING DUE TO LINGERING HAZARDOUS
WAVES.
LOW PRESSURE IS OVER ONTARIO AND IT WILL SLIDE TO THE EAST
TODAY...WHILE ITS COLD FRONT PASSES OVER THE LAKE THIS AFTERNOON.
AT THE SAME TIME HIGH PRESSURE BUILDS OVER THE CENTRAL PLAINS. THIS
WILL TIGHTEN THE PRESSURE GRADIENT OVER THE SOUTHERN END OF THE
LAKE...RESULTING IN LOW END GALES FORMING THIS MORNING THROUGH EARLY
THIS EVENING. WEST WINDS DIMINISH TO ARND 20 KT BY WEDNESDAY
MORNING AS HIGH PRESSURE PASSES TO THE SOUTH. WINDS PICK BACK UP ON
THE BACKSIDE OF THE HIGH LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING. A BRIEF PERIOD OF SW GALES TO 35 KT IS POSSIBLE DURING
THAT TIME. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED AS WELL FOR
WEDNESDAY AFTERNOON AND EVENING. WINDS WEAKEN WEDNESDAY NIGHT AS A
TROUGH OF LOW PRESSURE SITS OVER THE LAKE WEDNESDAY NIGHT THROUGH
THURSDAY. THE NEXT WEAK LOW MOVES OVER THE LAKE THURSDAY NIGHT
BEFORE SHIFTING EAST ON FRIDAY. WINDS TURN LIGHT AND VARIABLE
BEHIND THE LOW ON SATURDAY...BUT THEN TURN NORTH AND STRENGTHEN
SATURDAY NIGHT INTO SUNDAY IN RESPONSE TO THE NEXT SYSTEM. GUIDANCE
FEATURES ANOTHER LOW PUSHING UP THE OHIO RIVER VALLEY SATURDAY NIGHT
INTO SUNDAY WITH HIGH PRESSURE BUILDING DOWN THE PLAINS.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM TUESDAY TO 9 PM TUESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...9 AM
TUESDAY TO MIDNIGHT WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1154 PM CST MON DEC 16 2013
.DISCUSSION...
830 PM CST
CHARACTERISTIC OF THIS YOUNG 2013-2014 WINTER...ONE WEATHER ISSUE
DEPARTS AND ANOTHER QUICKLY FOLLOWS ON ITS HEELS. NOT ONLY IS THAT
NEXT ISSUE THE BRIEF SHOT OF SNOW TUESDAY MORNING...BUT ALSO
FREEZING FOG FOR AREAS ALONG AND SOUTH OF HIGHWAY 24 DURING THIS
EVENING. WE ISSUED A SPECIAL WEATHER STATEMENT FOR BOTH.
GOES WATER VAPOR SATELLITE AND UPPER AIR ANALYSES INDICATE THE
SHORT WAVE OF THE EARLIER SNOW IS HEADING EAST OVER LAKE MI ON A
STRONG 80 KT 500MB JET MAX. THE MAIN PRESSURE FALLS ARE LOCATED
EVEN FURTHER NORTH ACROSS THE FAR NORTHERN GREAT LAKES...SO THE
SURFACE REFLECTION ACROSS OUR AREA HAS BEEN WEAK. THIS HAS HELPED
ALLOW FOR SATURATION IN THE LOW-LEVELS AND THE INABILITY TO ADVECT
IT AWAY. BOTH THE 00Z DVN AND ILX SOUNDINGS SHOWED STRONG
INVERSIONS OF AROUND 7C WITH NEARLY COMPLETE SATURATION BELOW.
SATELLITE AND OBSERVATIONS CORRELATE WITH THIS LOW-LEVEL MOISTURE
WELL...DEPICTING LOW VISIBILITIES ACROSS CENTRAL IL.
LAW ENFORCEMENT HAS REPORTED THIS ALONG WITH ICY ROADS IN FORD AND
BENTON COUNTIES AS TEMPERATURES ARE WELL BELOW FREEZING. ITS NOT
IMPOSSIBLE THERE IS A LITTLE DRIZZLE IN THIS MUCK AS WELL GIVEN
THE DECENT WIND FLOW AND SLIGHT ASCENT AT AND JUST ABOVE THE
INVERSION LEVEL. EVENTUALLY WESTERLY SURFACE WINDS DO INCREASE
SOME AS THE PRESSURE GRADIENT TIGHTENS OVERNIGHT. RAP AND HRRR
VISIBILITY AND CIG FORECAST DO TRY TO SHOW THE VERY LOW SATURATION
ADVECTING EAST BY EARLY OVERNIGHT AND THAT SEEMS
REASONABLE...THOUGH THEY COULD BE A LITTLE HASTY WITH THAT. GIVEN
THE SOMEWHAT LIMITED EXPECTED DURATION AND REPORTS OF VISIBILITY
NOT BEING AS LOW AS ONE QUARTER MILE IN OUR FORECAST AREA...HAVE
JUST GONE WITH AN SPS AS OPPOSED TO AN ADVISORY.
NEXT QUICK MOVING CLIPPER IS SEEN IN NW MN ON WATER VAPOR AND IS
ON A PATH FOR THE CWA BY DAYBREAK. THE GOING TIMING IN THE GRIDS
LOOKS GREAT COMPARED TO SHORT TERM/HIGH RES GUIDANCE WHICH SEEMED
TO HAVE HANDLED TODAYS SIMILAR EVENT WELL. RATIOS LOOK HIGHER WITH
THE TUE MORNING EVENT THAN TODAY...AND THE LATEST LOCAL 8KM ARW
DOES SHOW A COUPLE HOURS OF NEAR 25:1 RATIOS WHICH MAY BE A BIT
HIGH...BUT DO AT LEAST INDICATE THAT BURST POTENTIAL DURING RUSH
HOUR. TIMING AND MAGNITUDE OF WIND GUST INCREASE STILL LOOKS
REPRESENTATIVE AND THE FORECAST SPEEDS SHOULD BE ENOUGH TO
REALIZE PATCHY BLOWING OF THE FRESH SNOWFALL IN OPEN AREAS.
MTF
//PREV DISCUSSION...
305 PM CST
NUMEROUS FORECAST CONCERNS GOING THROUGH THE WEEKEND AS THE UPPER
FLOW PATTERN SHIFTS FROM FAVORING NORTHWEST FLOW AND PERIODIC
CLIPPERS TO A SOUTHWESTERLY FLOW SUPPORTING A BRIEF WARM UP FOLLOWED
BY THE POTENTIAL FOR STRONGER SOUTHWEST SYSTEMS.
EARLY AFTERNOON WATER VAPOR IMAGERY SHOWS A BROAD TROUGH OVER MOST
OF THE U.S. WITH BROAD RIDGING COMING OVER THE WEST COAST OF NORTH
AMERICA. EMBEDDED IN THE BROAD TROUGH ARE A SERIES OF WAVES...THE
FIRST OF WHICH IS ENTERING THE LOCAL AREA BRINGING BANDS OF SNOW.
THE NEXT WAVE OF NOTE IS MORE SUBTLE AS IT MOVES SOUTHEAST ACROSS
THE CENTRAL ALBERTA/SASKATCHEWAN BORDER AND GENERATES SNOW INTO
NORTHEASTERN MONTANA. THIS WAVE WILL MOVE INTO THE LOCAL AREA
TOMORROW MORNING. OTHERWISE...THE PATTERN WILL BECOME LESS AMPLIFIED
DURING MID WEEK AS THE MAIN UPPER TROUGH PUSHES EAST FOLLOWED BY THE
BROAD RIDGING CURRENTLY TO THE WEST.
TONIGHT AND TUESDAY...THE CURRENT CLIPPER WILL BE DEPARTING THE AREA
THROUGH THE EARLY EVENING HOURS BRINGING SNOW TO AN END AND TURNING
WINDS WESTERLY. ATTENTION TURNS TO THE MORE SUBTLE WAVE MOVING
SOUTHEAST ACROSS THE CENTRAL ALBERTA/SASKATCHEWAN BORDER AND A
SURFACE LOW TO THE EAST OF THE WAVE OVER MANITOBA WHICH WILL ALSO
MOVE SOUTHEAST WITH THE CENTER TRACKING INTO WESTERN ONTARIO TUESDAY
MORNING. A COLD FRONT WILL TRAIL THE LOW AND PUSH ACROSS THE LOCAL
AREA DURING THE MORNING. ANOTHER ROUND OF SNOW WILL LIKELY ACCOMPANY
THE PASSAGE OF THE UPPER WAVE AND SURFACE COLD FRONT. GUIDANCE
CONTINUES TO SHOW A RANGE OF SOLUTIONS WITH THE EXTENT/AMOUNT OF THE
PRECIP ACROSS THE AREA BUT GENERALLY HAS BEEN MORE BULLISH WITH
SNOWFALL COVERAGE OVER THE AREA THAN EARLIER RUNS. THIS FALLS IN
LINE WITH THE OBSERVED TRENDS OF THE CLIPPER LAST NIGHT AND THE ONE
CURRENTLY CROSSING THE AREA AND SEE LITTLE TO SUPPORT HAVING
DIFFERENT EXPECTATIONS FOR THIS NEXT ONE. WILL CONTINUE WITH THE
HIGH POPS ACROSS THE NORTHERN QUARTER TO THIRD OF THE AREA...WITH
THE FOCUS FOR MOST INTENSE AND LONGEST DURATION OF SNOW ALONG AND
NORTH OF A ROCKFORD TO CHICAGO TO VALPARAISO LINE...WHILE LIGHTER
SNOW FALLS TO THE SOUTH OF THIS LINE. THE UPPER WAVE LOOKS TO BE
SLIGHTLY WEAKER THAN THE ONE CURRENTLY CROSSING THE AREA BUT DOES
LOOK TO STRENGTHEN A BIT AS IT APPROACHES IN CONJUNCTION WITH A
BETTER ALIGNMENT OF THE LEFT EXIT OF AN UPPER JET. MODEL GUIDANCE
SHOWS A RANGE OF SNOWFALL AMOUNTS FROM VERY LITTLE TO A FEW INCHES
AND EVEN DIFFERS IN THE MAGNITUDE OF FORCING RELATIVE TO THE FAVORED
CRYSTAL GROWTH REGION. AT THIS POINT FEEL THE BEST ROUTE IS TO STICK
WITH THE OBSERVED TRENDS OF RECENT CLIPPERS AND ACCOUNT FOR THE
EXPECTATION OF SOME BETTER ORGANIZATION OF THE UPPER WAVE AND
FAVORED JET PLACEMENT. WITH THIS IN MIND FEEL THAT IT IS LIKELY THAT
NORTHERN PORTIONS OF THE AREA WILL SEE ANOTHER 1 TO POSSIBLY 2 INCH
EVENT WITH HIGH SNOW RATIOS. STEEP MID LEVEL LAPSE RATES AND GOOD
FORCING IN THE SNOW GROWTH ZONE SIMILAR TO TODAY SUPPORT
ACCUMULATION RATES OF 0.5 TO 0.75 IN/HR. CONTINUED WITH A SNOW RATIO
OF 16-18:1 OVERALL. MAY BE ABLE TO USE AMOUNTS/RATIOS/RATES FROM THE
CURRENT SNOW TO BETTER REFINE FOR THE MORNING. TIMING-WISE...SNOW
SHOULD MOVE INTO THE NORTHWEST PART OF THE AREA TOWARD DAYBREAK AND
THE CHICAGO METRO RIGHT AROUND OR JUST AFTER DAYBREAK THEN EXIT TO
THE EAST DURING THE LATE MORNING HOURS. THE PASSAGE OF THE COLD
FRONT WILL BRING A SHIFT TO NORTHWEST WINDS WHICH WILL INCREASE WITH
GUSTS PUSHING 35-40 MPH FROM LATE MORNING THROUGH THE AFTERNOON
LEADING TO BLOWING SNOW. HIGHS SHOULD BE RIGHT AROUND 30...THOUGH
THERE COULD BE A SLIGHT DECREASE IN TEMPS IN THE AFTERNOON WITH SOME
COOL ADVECTION BUT CLEARING SKIES AND SUNSHINE MAY OFFSET THIS. LOWS
TUESDAY NIGHT SHOULD FALL INTO THE MID TEENS WITH WINDS DIMINISHING
AND TURNING SOUTHWEST.
WEDNESDAY THROUGH FRIDAY...THE UPPER TROUGH CARVED OUT BY THE SERIES
OF CLIPPERS WILL SWING TO THE EAST AND OFF THE NEW ENGLAND COAST
WEDNESDAY ALLOWING FOR BROAD UPPER RIDGING TO SPREAD ACROSS THE
U.S. THIS WILL BRING A PUSH OF MID LEVEL WARM ADVECTION TO THE
REGION WEDNESDAY INTO THURSDAY WITH H85 TEMPS WARMING TO AROUND +6C
OR SO AND H92 TEMPS WARMING JUST ABOVE 0C. THIS WILL ALLOW FOR
SURFACE WARMING AS WELL BUT SNOW COVER WILL BE ONE LIMITING FACTOR.
TEMPS WEDNESDAY WILL BE TRICKY BECAUSE ASIDE FROM SOME MID LEVEL WAA
CLOUDS EARLY THERE WILL LIKELY BE AT LEAST SOME SUN AS WELL AS A
STRONG SOUTHWEST WIND. BOTH OF THESE POINT TOWARD WARMER HIGHS GIVEN
THAT THE LOWER ATMOSPHERE WILL STILL BE RELATIVELY DRY. THIS SHOULD
ALLOW MOST AREAS TO WARM TO OR JUST ABOVE FREEZING. BY THURSDAY...AN
UPPER TROUGH WILL BE WORKING INTO THE WESTERN U.S. WITH THE UPPER
FLOW SPLITTING INTO TWO STREAMS AS THE TROUGH DIGS SOUTH AND CUTS
OFF OVER OR JUST OFF THE CALIFORNIA COAST. HEIGHT FALLS AHEAD OF
THIS TROUGHING WILL LEAD TO SURFACE LOW PRESSURE DEVELOPMENT ACROSS
THE CENTRAL/SOUTHERN ROCKIES WITH AN INVERTED TROUGH AXIS EXTENDING
NORTHEAST ACROSS THE LOCAL AREA. DEEP LAYER MOISTURE WILL BE
INCREASING THURSDAY LEADING TO PRECIP CHANCES...ESPECIALLY LATER IN
THE DAY WITH LOW LEVEL MOIST ADVECTION ACTING ON THE SNOW PACK TO
LIKELY GENERATE FOG. THIS WILL PROBABLY KEEP TEMPS IN THE MID TO
UPPER 30S. PRECIP MAY END UP BEING MORE DRIZZLE THAN FALLING PRECIP
THROUGH THE DAY AND POSSIBLY THE EVENING/OVERNIGHT. THE UPPER FLOW
LOOKS TO REMAIN SPLIT WITH NORTHERN STREAM ENERGY KICKING THE
SURFACE LOW NORTHEAST RIGHT ACROSS THE AREA THURSDAY NIGHT AND
FRIDAY MORNING. THIS WILL ALSO BRING A COLD FRONT THOUGH THE AREA
EARLY FRIDAY. ANY RAIN WILL LIKELY TURN TO A MIX OR ALL SNOW FRIDAY
MORNING. OVERALL PRECIP AMOUNTS LOOK LIGHT WITH WEAK OR DISJOINTED
FORCING. HIGHS FRIDAY WILL LIKELY BE EARLY THEN FALL THROUGH THE
DAY.
SATURDAY THROUGH MONDAY...THIS PERIOD BEARS WATCHING AS ENERGY FROM
THE SOUTHERN STREAM CUTOFF UPPER LOW IS EXPECTED TO KICK NORTHEAST
THIS WEEKEND AS A REINFORCING UPPER TROUGH MOVES SOUTHEAST INTO THE
NORTHERN PLAINS. THIS WILL LIKELY SEND A SURFACE LOW AND/OR INVERTED
TROUGH NORTHEAST WITH RECENT GUIDANCE BRINGING IT SOUTHEAST OF THE
AREA. RIGHT NOW THE FAVORED TIME FOR THE SYSTEM TO BRING PRECIP TO
THE AREA WOULD BE LATER SATURDAY INTO SUNDAY. GIVEN THE PRECEDING
SHIFT IN THE UPPER FLOW TO A MORE ZONAL PATTERN AHEAD OF THE
TROUGHED FLOW...THERMAL FIELDS WILL BE MORE CRITICAL IN THAT THEY
WILL LIKELY BE WARM ENOUGH FOR A RANGE OF PRECIP TYPES TO OCCUR
DEPENDING ON WHERE THE LOW TRACKS. OVERALL SYSTEM STRENGTH AND
MOISTURE FEED SUPPORT HIGHER END PRECIP AMOUNTS WITH AFFECTED AREAS
DEPENDING ON THE TRACK. STILL VERY EARLY TO HAVE MUCH CONFIDENCE IN
DETAILS GIVEN THE EVOLUTION OF UPPER FLOW THAT NEEDS TO TAKE PLACE
IN THE MEANTIME BUT THERE LOOKS TO BE A GOOD CHANCE FOR A SYSTEM TO
BE AFFECTING THE REGION.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS WITH PERIODS OF IFR PSBL OVERNIGHT. MVFR PERSISTS
THROUGH THE MORNING.
* SNOW RETURNS ARND 12Z WITH VSBY DROPPING TO AROUND A MILE. BRIEF
REDUCTIONS TO BELOW 1 SM PSBL.
* STRONG WEST WINDS SET UP LATE IN THE MORNING THROUGH THE
AFTN...20 KT GUSTING TO ARND 30 KT.
JEE
//DISCUSSION...UPDATED 06Z...
A LOW PRESSURE TROUGH IS OVER THE REGION WITH THE PARENT LOW OVER
SOUTH CENTRAL CANADA. ANOTHER UPPER LEVEL WAVE WILL APPROACH FROM
THE NW EARLY THIS MORNING KICKING OFF MORE SNOW. CIGS ARE
CURRENTLY MVFR WITH THE ONLY IFR SITES BEING RFD AND GYY. NOT SURE
HOW THE WIDESPREAD IFR CIGS WEST AND SOUTH OF THE TERMINALS ARE
STAYING OUT OF THE TERMINALS...BUT BETTING NO ONE IS COMPLAINING.
WHILE THE OBS ARE NOT SHOWING IFR...KEPT THE TEMPOS GOING WITH IFR
THROUGH THE MORNING. VSBYS HAVE ALSO COME UP WITH THE FOG
REMAINING ALSO TO THE SOUTH AND WEST OF THE TERMINALS. THIS IS
PROBABLY DUE TO THE SLIGHTLY DRIER AIR OVER THE TERMINALS.
WEST WINDS WILL PICK UP AS THE GRADIENT TIGHTENS...SO THINKING ALL
SITES OTHER THAN RFD SHOULD REMAIN VFR OVERNIGHT. THE SNOW ARRIVES
AROUND DAYBREAK AT RFD AND IT SHOULD BE ANOTHER QUICK SYSTEM.
FORCING LOOKS DECENT IN THE SNOW GROWTH ZONE...SO THINKING 1 1/2SM
IS STILL REASONABLE. MAY SEE A BRIEF PERIOD OF HEAVIER AND LESS
THAN 1 SM VSBY...BUT NOT ENTIRELY SURE WHERE IN THE SNOW WINDOW
THIS WOULD OCCUR. WILL LIKELY ADD A TEMPO FOR REDUCED VSBY LATER.
WINDS REALLY RAMP UP BY MID MORNING WITH GUSTS ARND 30 KT
EXPECTED. THE ADDED MIXING WILL HELP LIFT CIGS TO VFR WITH VFR
CONDITIONS EXPECTED FOR THE REST OF THE PERIOD. GUSTS DIMINISH IN
THE AFTN WITH WINDS BCMG SW BY WEDNESDAY MORNING.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN CIG TRENDS...LOW CONFIDENCE OF IFR CIGS
RETURNING OVERNIGHT.
* HIGH CONFIDENCE IN SNOW TOMORROW.
* MEDIUM CONFIDENCE IN VSBY FALLING TO BELOW 1SM IN SNOW...BUT
LOW CONFIDENCE IN THE TIME WINDOW.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR.
THURSDAY...CHANCE OF RAIN W/ FOG.
FRIDAY...CHANCE OF RAIN OR SNOW BECOMING ALL SNOW BY THE
AFTERNOON.
SATURDAY...CHANCE OF SNOW.
SUNDAY...CHANCE OF SNOW.
RODRIGUEZ
&&
.MARINE...
204 PM CST
A SERIES OF DISTURBANCES WILL LEAD TO SEVERAL WIND SHIFTS THROUGH
THE REMAINDER OF THE WEEK...AS WELL AS A BRIEF PERIOD OF GALES WHICH
IS EXPECTED TUESDAY. TODAY HIGH PRESSURE IS STARTING TO DRIFT EAST
OF LAKE MICHIGAN WITH SOUTHWEST FLOW INCREASING IN ADVANCE OF AN
APPROACHING COLD FRONT. THIS FIRST FRONT WILL MOVE ACROSS LAKE
MICHIGAN WITH WINDS VEERING TO WESTERLY OVERNIGHT. A SECOND FRONT
WILL BE RIGHT ON ITS HEELS THOUGH...AND WILL PUSH ACROSS LAKE
MICHIGAN TUESDAY AFTERNOON WITH WINDS SHIFTING NORTHWESTERLY. A
BETTER SURGE OF COLD AIR WILL BE ASSOCIATED WITH THIS SECOND
FRONT...AS WELL AS A TIGHTER PRESSURE GRADIENT WITH A MODERATE RIDGE
BUILDING ALONG THE MISSISSIPPI VALLEY...LEADING TO A PERIOD OF WEST
TO NORTHWEST GALES...PARTICULARLY ACROSS THE SOUTH HALF OF THE LAKE.
GALES WILL DIMINISH TUESDAY NIGHT AND WINDS WILL BEGIN TO BACK TO
THE SOUTHWEST WEDNESDAY AS THE RIDGE PROGRESSES EAST ACROSS LAKE
MICHIGAN. SOUTHWEST WINDS FRESHEN UP AGAIN WEDNESDAY NIGHT AS YET
ANOTHER FRONT IS POISED TO SWEEP ACROSS THE LAKE EARLY THURSDAY.
MODERATE NORTHERLY FLOW IS EXPECTED FRIDAY BEHIND THE FRONT AS
ANOTHER LOW PRESSURE SKIRTS TO THE EAST...JUST SOUTH OF THE
GREAT LAKES.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM TUESDAY TO 9 PM TUESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...9 AM
TUESDAY TO MIDNIGHT WEDNESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1147 PM CST MON DEC 16 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 302 PM CST MON DEC 16 2013
MAIN SHORT TERM CONCERN IS ON SNOW POTENTIAL LATE TONIGHT INTO
TUESDAY MORNING.
CURRENTLY AS OF 21Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO BRITISH COLUMBIA WHILE
TROUGHING DOMINATED EASTERN CANADA AND IN GENERAL THE EASTERN U.S..
WITHIN THIS TROUGHING...TWO SHORTWAVES WERE NOTED OVER SOUTHERN
MINNESOTA AND IN NORTH DAKOTA. THE SHORTWAVE OVER SOUTHERN MINNESOTA
WAS PRODUCING A BAND OF SNOW ON RADAR MARCHING ACROSS WISCONSIN...
CLIPPING PORTIONS OF NORTHEAST IOWA INTO NORTHERN ILLINOIS. THE
NEXT AREA OF SNOW EXISTS OVER EASTERN MONTANA INTO WESTERN NORTH
DAKOTA...ON THE WEST SIDE OF THE SHORTWAVE THERE. THIS BAND OF
SNOW IS BEING PRODUCED MORE BY MID-LEVEL FRONTOGENESIS AND UPPER
DIVERGENCE IN THE RIGHT ENTRANCE REGION OF A 110-130 KT JET STREAK
IN NORTHEAST MONTANA PER RAP ANALYSIS. CLOSER TO THE FORECAST
AREA...COMBINATION OF LOW SUN ANGLE AND A SURFACE RIDGE OF HIGH
PRESSURE IN PLACE HAS BEEN LIMITING MIXING...KEEPING A STRATUS
DECK IN PLACE FOR MUCH OF THE DAY. THE AIRMASS IS ALSO COOL IN A
SHALLOW LAYER...SINCE 850MB TEMPS RANGE FROM 4C TO -4C SOUTHWEST
TO NORTHEAST ACROSS THE FORECAST AREA. 12Z DVN SOUNDING REALLY
REFLECTS THE SHALLOW COOL LAYER AND THE STRATUS WITH A SATURATED
VERY STRONG INVERSION BETWEEN 925MB AND 825MB.
FOCUS IS ON THE SHORTWAVE COMING OUT OF NORTH DAKOTA...ALONG WITH
THE MID LEVEL FRONTOGENESIS AND UPPER JET STREAK ON ITS WESTERN
SIDE...WHICH ARE PROGGED TO DIG SOUTHEAST TO DUBUQUE BY 12Z TUESDAY.
MODELS ARE IN VERY GOOD AGREEMENT ON ALL OF THE AFOREMENTIONED
FEATURES THUS HAVE FOLLOWED THE CONSENSUS. WE SHOULD SEE A DRY
EVENING AREA WIDE...THEN THE BAND OF SNOW UP IN WESTERN NORTH DAKOTA
WILL ARRIVE GENERALLY TO LOCATIONS ALONG/NORTH OF US-20. RAISED
PRECIPITATION CHANCES UP TO 70 IN THIS AREA...AND EVEN INCLUDED SOME
CHANCES A BIT FARTHER SOUTH TOWARDS BUT NOT TO THE I-80 CORRIDOR IN
THE EVENT THE BAND SLIPS A BIT FARTHER SOUTH. MUCH OF THE SNOW LOOKS
TO BE CONFINED BETWEEN 06-12Z TUESDAY...WITH PERHAPS A LITTLE SNOW
LINGERING IN NORTHWEST ILLINOIS BETWEEN 12-14Z BEFORE IT PUSHES
OFF TO THE EAST. TOTAL SNOW AMOUNTS MAY BE UPWARDS OF 1/2 INCH TO
1 INCH...HIGHEST NEAR DUBUQUE.
OTHER ISSUES OF NOTE IN THE SHORT TERM.
1. WINDS PICKING UP IN THE WAKE OF THE SHORTWAVE PASSAGE. THE
PRESSURE GRADIENT IS PROGGED TO REALLY TIGHTEN UP TUESDAY
MORNING...RESULTING IN WEST TO NORTHWEST SPEEDS OF 15 TO 25 MPH WITH
GUSTS PERHAPS APPROACHING 35 MPH. WINDS DO NOT LOOK TO RELAX UNTIL
LATE IN THE DAY WITH DIURNAL COOLING AND THE APPROACH OF A SURFACE
RIDGE AXIS. THE WINDS COULD BLOW SOME OF THE SNOW AROUND THAT FALLS
TONIGHT INTO TUESDAY MORNING.
2. CLOUDS. THE STRATUS DECK CURRENTLY IN PLACE LOOKS TO CLEAR OUT
THIS EVENING AS WINDS SHIFT WEST...DRAWING DRIER AIR IN OUT OF
NEBRASKA AND WESTERN IOWA. SKIES HAVE BEEN CLEARING IN WESTERN IOWA
ALL DAY REFLECTING THE DRY AIR. CLOUDS SHOULD TEMPORARILY INCREASE
WITH THE APPROACH OF THE NORTH DAKOTA SNOW BAND...THEN DECREASE
AGAIN ON TUESDAY IN ITS WAKE.
3. TEMPERATURES. IF WINDS CAN DECOUPLE THIS EVENING WHEN SKIES ARE
CLEAR...READINGS COULD DIP INTO THE SINGLE DIGITS. CONFIDENCE IS NOT
HIGH ENOUGH TO GO THAT COLD...THUS STAYED CLOSER TOWARDS THE
CONSENSUS. HIGHS DEFINITELY WARMER TOMORROW WITH MORE SUN AND WINDS
FOR MIXING...THOUGH 850MB TEMPS ARE COOLER BETWEEN -8 AND -10C.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 302 PM CST MON DEC 16 2013
MAIN LONG TERM FORECAST CONCERNS ARE ON PRECIPITATION TYPES
WEDNESDAY NIGHT THROUGH FRIDAY...AND AGAIN SATURDAY INTO SUNDAY.
MODELS REMAIN CONSISTENT IN SHOWING A MAJOR PATTERN CHANGE OVER THE
NEXT FEW DAYS...RESULTING FROM A POTENT TROUGH DIGGING DOWN FROM
NORTHERN BRITISH COLUMBIA AT 00Z WEDNESDAY TO SOUTHERN CALIFORNIA BY
00Z FRIDAY. THIS MODULATES THE PATTERN DOWNSTREAM OVER THE
FORECAST AREA FROM NORTHWEST FLOW ON TUESDAY...TO ZONAL ON
WEDNESDAY...AND FINALLY SOUTHWESTERLY ON THURSDAY. IN RESPONSE TO
THIS PATTERN CHANGE...WARM ADVECTION IS EXPECTED...WITH MOISTURE
ADVECTION COMING INTO PLAY AS WELL ONCE HIGH PRESSURE MOVES OUT OF
THE WAY OF THE GULF OF MEXICO COME WEDNESDAY.
AFTER WHAT WILL BE QUIET WEATHER TUESDAY NIGHT AND WEDNESDAY...
THINGS GET MORE INTERESTING FOR WEDNESDAY NIGHT AND THURSDAY. 16.12Z
NAM/GFS/ECMWF ALL SHOW LOW LEVEL SATURATION TAKING PLACE WEDNESDAY
NIGHT...WITH THE DEPTH OF THE SATURATION GROWING IN TIME THROUGH
THURSDAY. AS HIGHER MOISTURE IMPINGES ON THE COOLER...SNOW PACK OVER
THE AREA...ANTICIPATING AREAS OF FOG TO DEVELOP WEDNESDAY EVENING.
MAY EVENTUALLY NEED A DENSE FOG ADVISORY. IN ADDITION...THERE COULD
EVEN BE SOME DRIZZLE IN THIS FOG WEDNESDAY NIGHT...AS SUGGESTED BY
THE 16.12Z NAM QPF FIELDS...BUT CONFIDENCE IS TOO LOW TO MENTION
PRIOR TO 12Z THURSDAY. BETTER MODEL AGREEMENT AFTER 12Z THURSDAY FOR
DEEPER LOW LEVEL MOISTURE AND THE ISENTROPIC LIFT DOES GRADUALLY
INCREASE. THUS...PRECIPITATION CHANCES INCREASE THROUGH THE DAY
THURSDAY. SOUNDINGS DEPICT NO ICE IN THE CLOUDS...THUS ANY
PRECIPITATION THAT FALLS WILL BE IN LIQUID FORM...WITH THE SURFACE
AND POSSIBLY EVEN GROUND TEMPERATURE DICTATING WHETHER IT FREEZES
ON CONTACT. IT DOES SEEM THAT THE GREATER ICING THREAT WOULD BE
NORTH OF I-80 THURSDAY MORNING...SINCE TEMPERATURES IN MOST PLACES
ALONG/SOUTH OF I-80 MAY STRUGGLE TO FALL BELOW FREEZING WEDNESDAY
NIGHT. A COLD FRONTAL BOUNDARY IS PROGGED TO SLOWLY SLIDE
SOUTHEAST THROUGH THE FORECAST AREA ON THURSDAY...WHICH COMBINED
WITH DAYTIME HEATING SHOULD HELP TO GET RID OF THE FOG.
AS WE HEAD TOWARDS THE WEEKEND...MODELS ARE IN GOOD AGREEMENT
SPLITTING UP THAT WESTERN TROUGH. THE NORTHERN PORTION SHORTWAVE
TROUGH IS PROGGED TO SLIDE ACROSS MN AND WI...WHICH SIMULTANEOUSLYBRINGS
A SURFACE LOW NORTHEAST THROUGH THE FORECAST AREA. PRECIPITATION
SHOULD INTENSIFY SOME AHEAD OF THE SURFACE LOW...ENOUGH TO WARRANT
HIGHER PRECIPITATION CHANCES. THE PRECIPITATION THEN EXITS OFF TO
THE EAST FRIDAY WITH THE PASSAGE OF THE TROUGH. AGAIN...NO ICE IS
SUGGESTED IN THE CLOUDS...MEANING EITHER RAIN OR FREEZING RAIN AT
THE SURFACE DEPENDING ON THE SURFACE TEMPERATURE.
FOCUS THEN SHIFTS TO THE SOUTHERN PORTION OF THE WESTERN
TROUGH...WHICH THE 16.12Z ECMWF/CANADIAN/GFS ALL SHOW LIFTING UP
THROUGH THE CENTRAL PLAINS AND ILLINOIS SATURDAY INTO SUNDAY. WE
NEED TO WATCH THIS SHORTWAVE AND ASSOCIATED SYSTEM CLOSELY FOR
SNOW...SLEET AND FREEZING RAIN. THE THREAT FOR SLEET AND FREEZING
RAIN RIGHT NOW SEEMS TO BE HIGHEST SOUTHEAST OF A LINE FROM ROCK
FALLS TO MOLINE IL AND MT. PLEASANT IA. RAISED PRECIPITATION
CHANCES IN THIS AREA TOO FOR SATURDAY NIGHT TOWARDS 60 AS MODELS
ARE COMING INTO BETTER AGREEMENT. COLDER AND DRIER AIR WILL FILTER
IN BEHIND THIS SYSTEM FOR SUNDAY NIGHT AND MONDAY AS AN ARCTIC
HIGH PRESSURE AREA BUILDS SOUTH INTO THE REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1125 PM CST MON DEC 16 2013
BACK EDGE OF LOW CLOUDS WITH IFR TO LIFR CIGS AND LIGHT FOG HAS
MOVED EAST OF KCID TERMINAL AND EXPECTED TO CONTINUE SLOW AND
STEADY EASTWARD MOVEMENT OVERNIGHT EXITING REST OF THE TERMINALS.
SOME CONCERNS WITH RECENT SATELLITE AND OB TRENDS DEPICTING LOW
CLOUDS SLOWING OVER FAR NORTHEAST IOWA AHEAD OF SURFACE TROUGH.
THIS WILL NEED TO BE WATCHED FOR POSSIBILITY OF LOW CLOUDS
WITH IFR/MVFR CIGS MOVING BACK INTO TERMINALS ESPECIALLY KCID AND
KDBQ EARLY TUESDAY MORNING AS FLOW TURNS MORE NORTHWESTERLY.
AN UPPER LEVEL DISTURBANCE OVER THE DAKOTAS WILL PASS THROUGH THE
AREA TUESDAY MORNING AND MAY SEE SOME SNOW SHOWERS SWEEP THROUGH
THE AREA WITH THIS FEATURE. POTENTIAL TO SEE BRIEF PERIODS OF
VSBYS AROUND 1 MILE WITH QUICK ACCUMS OF A FEW TENTSH OF AN INCH
AND CIGS 1-2KFT AGL WITH BURST OF SNOW IN THE SHOWERS. COVERAGE
AND IMPACT TO TERMINALS UNCERTAIN THUS LIMITED MENTION TO JUST VCSH
AT ALL SITES FOR NOW DURING THE MORNING. COLD ADVECTION AND
TIGHTENING PRESSURE GRADIENT TO RESULT IN PERIOD OF GUSTY NORTHWEST
WINDS 15-30 KTS. HIGH PRESSURE BUILDS IN BY TUESDAY EVENING WITH
VFR CONDITIONS AND NORTHWEST WINDS 10-15 KTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...05
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1226 AM EST TUE DEC 17 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 347 PM EST MON DEC 16 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOWS PERSISTENT NW
FLOW ALF OVER THE GREAT LKS BTWN DEEP TROF OVER ERN NAMERICA AND RDG
ALONG THE W COAST. VERY COLD CNDN AIR IS IN PLACE OVER THE UPR LKS
WITH H5/H85 TEMPS JUST UNDER -30C/ARND -18 OR 19C. DISTURBANCE
RESPONSIBLE FOR SN ON SUN HAS NOW PUSHED E INTO QUEBEC...BUT ANOTHER
WELL DEFINED CLIPPER SHRTWV JUST E OF LK WINNIPEG EARLY THIS AFTN IS
FOLLOWING QUICKLY BEHIND. SHRTWV RDG/DRY MID LVL AIR SHOWN ON THE
12Z APX/GRB RAOBS BROUGHT DRY WX TO UPR MI EARLY THIS AFTN. ALTHOUGH
ABSOLUTE MSTR IS LIMITED FOR THE TRAILING DISTURBANCE WITH 12Z PWATS
NO HIER THAN 0.25-0.35 INCH IN MN...A BAND OF SN UNDER THE DEEP LYR
QVECTOR CNVGC/DPVA/ISENTROPIC ASCENT AHEAD OF THIS FEATURE IS MOVING
INTO WRN LK SUP. THE BAND IS RATHER NARROW...BUT VSBYS UNDER THE
HEAVIER SN HAVE FALLEN AS LO AS 1/4-3/4 MILES. THIS SN BAND SHIFTED
INTO THE WRN COUNTIES BY MID AFTN...AND THE VSBY AT IWD DROPPED TO
1/4SM FOR AN HR. SOME SHSN AND PERHAPS A VORTEX ARE PRESENT OVER
NCNTRL LK MI...AND THESE ARE DRIFTING TO THE NNE. ALTHOUGH SOME
LIGHT SN LINGERS BACK INTO NW MN BEHIND THIS BAND...VSBYS THERE ARE
AOA 3 MILES UNDER THE UPR LVL DRYING SHOWN ON WV IMAGERY/QVECTOR
DVGC IN THE WAKE OF THE SHRTWV TROF. IN FACT...THERE HAS BEEN SOME
CLRG OVER CENTRAL MN. FARTHER TO THE NW...THERE IS ANOTHER CLIPPER
DISTURBANCE DIGGING SEWD IN SASKATCHEWAN.
MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE POPS/SN AMNTS AND GOING
HEADLINE OVER THE ERN CWA ASSOCIATED WITH APRCHG CLIPPER SHRTWV.
FOCUS FOR TUE SHIFTS TO POTENTIAL IMPACT OF SECOND TRAILING
DISTURBANCE IN WRN CANADA AS WELL AS THE CHC FOR MORE LK EFFECT SN.
LATE THIS AFTN/THRU THIS EVNG...TENDED TO BUMP POPS UP TO
CATEGORICAL FOR A FEW HRS AT MOST PLACES W-E THIS AFTN INTO EARLY
EVNG WITH PASSAGE OF RATHER NARROW BAND OF SN UNDER AXIS OF H85-5
QVECTOR CNVGC AHEAD OF APRCHG SHRTWV. WITH 2G/KG SPECIFIC HUMIDITY
PRESENT NEAR H725 AND A 2-3 HR PERIOD OF HEAVIER SN...EXPECT MOST
PLACES WL SEE ARND AN INCH TO PERHAPS 2 INCHES OF SN UNDER THIS
HEAVIER BURST. THE ONE EXCEPTION WL BE IN THE SSW FLOW DOWNWIND OF
LK MI...WHERE SOME LK ENHANCEMENT WITH H85 TEMPS NEAR -16C/DEEPER
MSTR/DYNAMIC FORCING JUSTIFIES GOING WINTER WX ADVY UNTIL PASSAGE OF
THE BAND/WSHFT TO THE WSW AFT MIDNGT OVER THE E WL DIMINISH THESE
SHSN. FVRBL OMEGA PROFILE WITHIN THE DGZ WL AID IN SN ACCUMS. TO THE
W...JUST SOME LINGERING SCT -SHSN WL FOLLOW THE BAND UNDER MID LVL
DRYING/QVECTOR DVGC. WHERE THERE IS A BETTER CHC FOR AT LEAST
PARTIAL CLRG OVER THE SCNTRL...TENDED TO LOWER FCST MIN TEMPS A BIT
WELL INTO THE SINGLE NUMBERS ABV ZERO.
LATER TNGT/TUE...MOST OF THE EARLY MRNG SHOULD BE MOCLDY WITH JUST
SOME SCT -SHSN/FLURRIES UNDER QVECTOR DVGC IN THE WAKE OF THE
DEPARTING CLIPPER. THE SHRTWV NOW OVER SASKATCHEWAN IS FCST TO DIG
SEWD AND INTO THE UPR LKS BY 12Z TUE. ALTHOUGH MORE IMPRESSIVE
MSTR/DYNAMIC FORCING WL ACCOMPANY ANOTHER SHRTWV PASSING TO THE S IN
WI...ARRIVAL OF COLD FNT/DEEPER MSTR ASSOCIATED WITH THE
SASKATCHEWAN DISTURBANCE WL BRING A RETURN OF HIER POPS TO MAINLY NW
UPR MI ON TUE MRNG. THERE IS SOME DISAGREEMENT AMONG THE MODELS ON
HOW MUCH DEEPER MSTR WL ACCOMPANY THIS FROPA. IN GENERAL...THE 12Z
NAM/GFS SHOW MORE FVRBL ALIGNMENT BTWN THE DEEPER MSTR AND FROPA
TIMING. ALTHOUGH THERE IS SOME POTENTIAL FOR A BRIEF PERIOD OF LK
ENHANCED SN WITH H85 TEMPS RISING TO -10C IN THE NARROW THERMAL RDG
AHEAD OF THIS FNT...THE NAM/GFS SHOW DEEPER MSTR LINGERING FOR ONLY
A 3-6HR PERIOD. AS THE FNT SHIFTS TO THE E...THESE SHSN WL FOLLOW
THE BNDRY...WITH THE HIER POPS CLOSER TO LK SUP. BUT WL CARRY LOWER
CHC POPS EVEN OVER THE SCENTRAL...WHICH WL BE CLOSER TO THE DYNAMIC
FORCING ASSOCIATED WITH SHRTWV PASSING THRU WI. AFTER THE HEAVIER
SHSN END OVER THE NW...EXPECT LIGHTER MULTIPLE BAND LES TO IMPACT
THE WNW WIND SN BELTS THERE AS COLDER AIR WITH H85 TEMPS FALLING TO
ARND -18C BY 00Z WED FOLLOW THE BNDRY. NOT OUT OF THE QUESTION THERE
COULD BE ADVY SN FALL OVER THE NW THRU THE DAY...BUT CONCERNS
ABOUT TIMING OF DEEPER MSTR LOWER CONFIDENCE ENUF TO HOLD OFF ON A
HEADLINE FOR NOW.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 440 PM EST MON DEC 16 2013
EXPECT CONTINUED NW FLOW OVER THE KEWEENAW PENINSULA TUESDAY EVENING
WITH ANOTHER 1 TO ALMOST 2IN. A QUICK 1-4IN OF SNOW WILL BE POSSIBLE
E OF MUNISING AND N OF NEWBERRY TUESDAY NIGHT. MAY NEED TO HOIST A
LES ADVISORY FOR E ALGER AND N PORTIONS OF LUCE COUNTY...WITH THE
CONVERGENCE BEHIND THE EXITING LOW.
WITH THE 500MB TROUGH SET UP FROM E ONTARIO THROUGH THE LOWER GREAT
LAKES...AND A SIZABLE RIDGE DOMINATING THE W HALF OF THE
NATION...CHANCES ARE GOOD FOR RIDGING TO MOVE IN FOR MID WEEK. THE
RIDGE WILL SLIDE IN AT THE SFC AND ALOFT WEDNESDAY MORNING...AHEAD
OF A BROAD AREA OF LOW PRESSURE SET UP FROM SW AND SCENTRAL CANADA
THROUGH THE NORTHERN PLAINS. THE WARM WEATHER WILL CONTINUE FOR
WEDNESDAY AHEAD OF THIS LOW. ENJOY IT WHILE IT LASTS. WHILE READINGS
WILL BE ABOVE WHAT WE HAVE BEEN USE TO /HAVE NOT HAD TEMPS ABOVE 15F
AT NWS MQT SINCE THE FIRST 5 DAYS OF DECEMBER/...THEY WILL REMAIN
AROUND NORMAL FOR THIS TIME OF YEAR. HIGHS ARE TYPICALLY IN THE MID
TO UPPER 20S IN MID DECEMBER.
EXPECT THE RIDGE ALOFT TO QUICKLY TURNING TO MORE ZONAL FLOW
WEDNESDAY NIGHT WITH BOOKEND TROUGHS OVER THE FAR W AND E SECTIONS
OF THE UNITED STATES. BY 00Z THURSDAY THE SFC LOW WILL HAVE MOVED TO
THE SE...STRETCHING FROM E CO THROUGH LAKE SUPERIOR.
THE N EXTENT OF THE SFC LOW WILL SLOWLY SINK ACROSS LAKE MI AND
LOWER MI THROUGH THE DAY THURSDAY...WITH SW FLOW AT 500MB ON
THURSDAY IN RESPONSE TO THE LOW DIVING ALONG THE W COAST INTO
CA...AND THE NORTHERN LOW PUSHING ACROSS CENTRAL CANADA. A QUICK
TENTH OF AN INCH OR SO OF LIQUID FROM THURSDAY AFTERNOON THROUGH
THURSDAY EVENING. WITH SNOW RATIOS OF 20-25:1...WILL LIKELY HAVE
1-2IN OF SNOW CWA WIDE BY MIDNIGHT.
THE SFC LOW WILL THEN CONSOLIDATE ACROSS LOWER MI AND LAKE HURON AT
12Z FRIDAY...WITH UPPER MI AND THE UPPER GREAT LAKES RETURNING TO
OUR TROUGH PATTERN FROM THURSDAY THROUGH NEXT MONDAY. ANOTHER 1-2IN
OF SNOW POSSIBLE BEFORE DRYING UP BY LATE FRIDAY MORNING.
A BRIEF RIDGE WILL ATTEMPT TO BUILD IN ALOFT SATURDAY OVER THE SE
CWA...AS THE NEXT SIGNIFICANT TROUGH PUSHES IN FROM CENTRAL CANADA
AND THE PLAINS STATES. A SERIES OF EMBEDDED WAVES WILL CONTINUE TO
NEAR FROM THE NW THROUGH AT LEAST MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1226 AM EST TUE DEC 17 2013
A SERIES OF SHORTWAVE TROUGHS COMBINED WITH UPSLOPE FLOW AT CMX AND
IWD WILL BRING PERIODS OF LOWER CONDITIONS THROUGH THE TAF PERIOD AT
ALL SITES. THE WORST CONDITIONS ARE EXPECTED AT CMX AND IWD WHERE
UPSLOPE FLOW WILL FAVOR LOWER CIGS AND VIS. SKIES MAY CLEAR OUT
TONIGHT AT IWD AS SCATTERED CLEARING WAS NOTED UPSTREAM OVER
NCENTRAL MN...BUT NOT COMPLETELY CERTAIN ON EXTENT OF CLEARING
THERE. LOW LEVEL FLOW WILL NOT BE AS FAVORABLE FOR LOWER CONDITIONS
AT SAW...SO BEST CONDITIONS ARE EXPECTED THERE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 355 PM EST MON DEC 16 2013
S WINDS UP TO 25 TO 30 KTS THIS AFTERNOON AHEAD OF AN APPROACHING
LOW PRESSURE TROUGH WILL SHIFT TO THE SW AND DIMINISH OVERNIGHT TO
20 TO 25 KTS AS THE TROUGH SHIFTS TO THE EAST. A STRONGER WEST TO
NORTHWEST WIND UP TO 30 KTS WILL DEVELOP ON TUE FOLLOWING THE
PASSAGE OF A COLD FRONT. NOT OUT OF THE QUESTION THERE COULD BE A
FEW GUSTS TO NEAR GALE FORCE OVER WESTERN LAKE SUPERIOR. NO GALES
ARE FORESEEN QUITE YET FROM TUESDAY NIGHT THROUGH
SATURDAY...ALTHOUGH A COUPLE OF PERIODS GET CLOSER TO GUSTS OF
25-30KTS. HIGH PRESSURE WILL MOVE INTO THE CENTRAL PLAINS TUESDAY
EVENING AND WILL PUSH A BRIEF RIDGE ACROSS LAKE SUPERIOR WEDNESDAY.
A TROUGH EXTENDING FROM A BROAD LOW OVER THE ROCKIES AND NORTHERN
PLAINS WILL MOVE INTO THE UPPER GREAT LAKES WEDNESDAY NIGHT AND
THURSDAY. EXPECT THE LOW TO SINK ACROSS LOWER MICHIGAN BY FRIDAY
MORNING. IN THE WAKE OF THE LOW...HIGH PRESSURE OVER THE CENTRAL
PLAINS FRIDAY MORNING SHOULD SLOWLY BUILD INTO THE UPPER GREAT LAKES
ON FRIDAY...AND REMAIN IN PLACE THROUGH FRIDAY NIGHT. WEAK LOW
PRESSURE WILL THEN PUSH ACROSS THE AREA FOR THE START OF THE WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 AM EST EARLY THIS MORNING FOR
MIZ007-014.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...TITUS
MARINE...KC/KF
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
356 AM CST TUE DEC 17 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST TUE DEC 17 2013
THE THERMAL RIDGE WEAKENED A BIT WITH THE PASSAGE OF A WEAK COLD
FRONT TONIGHT. AS A RESULT...HIGH PRESSURE IS BUILDING THROUGH THE
NRN AND CNTL HIGH PLAINS ALLOWING FOR RADIATIONAL COOLING IN MOST
VALLEYS. THE RUC SHOWS LOW PRESSURE REFORMING ACROSS THE HIGH
PLAINS TODAY AND THIS SHOULD LIFT A WARM FRONT PART WAY THROUGH
THE FCST AREA. THE WARM FRONT WOULD LIKELY REACH HIGHWAY 183 BY
LATE AFTN.
FCST HIGHS FOLLOW THE WARMEST MODEL...THE HRRR FOR HIGHS NEAR 60
ACROSS THE SOUTHWEST WHERE THE THERMAL RIDGE WILL BE IN PLACE ALL
DAY. JUST SCATTERED HIGH CLOUDS ARE EXPECTED AS A SOLID BANK OF
CIRRUS IS OVER BRITISH COLUMBIA THIS AM.
THE RAP MODEL SHOWS WEST WINDS AT H850MB AT 15 TO 30KT AND THE MODEL
CONSENSUS 500M AGL WINDS ARE WEST AND SOUTHWEST AT 10 TO 20KT WHICH
WOULD PRODUCE 10 TO 20 MPH WINDS AT THE SFC.
LOWS TONIGHT VARY WIDELY WITH TEENS IN VALLEYS TO NEAR 30 ACROSS THE
SANDHILLS. A SHALLOW INVERSION SHOULD FORM GIVEN THE LIMITED HIGH
CLOUD COVER EXPECTED AND WESTERLY H850MB WINDS OF 20 TO 40KT. H850MB
TEMPS RISE IN THE TEENS ACROSS WRN NEB.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 355 AM CST TUE DEC 17 2013
PRIMARY CONCERNS FOR THIS FORECAST PERIOD ARE TEMPERATURES FOR
WEDNESDAY AND THURSDAY...AS WELL AS PRECIPITATION CHANCES AND
TYPES FOR THURSDAY AND THURSDAY NIGHT.
THE SHORTWAVE TROUGH CURRENTLY OVER THE GULF OF ALASKA WILL SPLIT
WEDNESDAY AND WEDNESDAY NIGHT WHICH WILL IMPACT THE LOCAL AREA IN
DIFFERENT WAYS. ONE PART OF THIS ENERGY WILL DIG SOUTH ALONG THE
WEST COAST WHICH WILL HELP THE THERMAL RIDGE BUILD OVER THE PLAINS.
THE SECOND PIECE OF ENERGY WILL STAY IN THE NORTHERN STREAM WHICH
WILL MOVE ACROSS THE PLAINS AS A WEAK SHORTWAVE TROUGH THURSDAY AND
THURSDAY NIGHT...WHICH WILL PUSH AN ARCTIC COLD FRONT ACROSS THE
FORECAST AREA.
STARTING ON WEDNESDAY...IS STILL A QUESTION TO HOW WARM IT WILL GET.
AS MENTIONED ABOVE THE THERMAL RIDGE BUILDS IN WITH ANOMALOUSLY WARM
AIR SEEN ALOFT. AT 18Z WEDNESDAY MODELS INDICATE 850MB TEMPERATURES
WILL HAVE RISEN BETWEEN 11C AND 15C ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA. MODELS ARE ONLY MIXING THE BOUNDARY LAYER TO AROUND 875MB
SO DON/T REALIZE THE POTENTIAL WARMING. WINDS WILL BE FAIRLY LIGHT
WHICH WON/T HELP THE MIXING DEPTH...BUT DON/T THINK THE MODELS ARE
HANDLING THIS MIXING WELL AND IN MOST LOCATIONS WENT ABOVE MOST
GUIDANCE FOR HIGHS. MUCH OF THE NORTHERN TIER OF COUNTIES CONTINUES
TO HAVE SNOW ON THE GROUND WHICH AS OF MONDAY STILL HAD A STRONG
IMPACT ON TEMPERATURES AS HIGHS WERE ONLY IN THE LOW 40S...WITH
UPPER 50S AND LOW 60S OVER THE REST OF THE FORECAST AREA. SHOULD
HAVE CONTINUED MELTING TODAY...SO THE SNOW SHOULDN/T HAVE AS MUCH
IMPACT ON HIGHS...BUT WITH WET GROUND MAY NOT BE ABLE TO MIX TOO
MUCH SO CONTINUED THE TREND OF COOLER TEMPERATURES ACROSS THE NORTH.
THIS MAY NEED TO BE MODIFIED DEPENDING ON WHAT HIGHS DO TODAY.
COLD FRONT WILL PUSH SOUTH THROUGH THE FORECAST AREA WEDNESDAY
NIGHT...WITH THE COLDEST AIR LAGGING BEHIND THE FRONT. THE LOW
LEVELS START TO SATURATE BY 12Z THURSDAY BUT ABUNDANT DRY AIR IN THE
MID LEVELS WILL KEEP FROM THE NEED FOR PRECIPITATION CHANCES
WEDNESDAY NIGHT.
ON THURSDAY...THERE ARE STILL DISCREPANCIES AS TO HOW FAST THE COLD
AIR WILL MOVE IN. FOR EXAMPLE GFS ENSEMBLE MEMBERS VARY FROM 19F TO
42F FOR HIGHS AT KLBF. BECAUSE OF THESE DIFFERENCES STAYED FAIRLY
SIMILAR TO ONGOING FORECAST FOR HIGHS. WITH COLD AIR ADVECTION
THROUGH THE DAY...MAY SEE HIGHS EARLY WITH FALLING OR NEARLY STEADY
TEMPERATURES. IN TERMS OF PRECIPITATION FOR THURSDAY...THERE IS
AGREEMENT BETWEEN MODEL SOLUTIONS OF THE COLUMN BECOMING SATURATED
THURSDAY MORNING OVER THE NORTHERN PANHANDLE...AND WITH THE COLD AIR
ALREADY IN PLACE SHOULD START TO SEE SNOW IN THE MORNING HOURS. AS
THE ENTIRE COLUMN COOLS...WITH SOME LAYERS REACHING THE DENDRITIC
GROWTH ZONE...MIGHT GET SOME HIGHER SNOW TO LIQUID RATIO SNOWS UP
OVER NORTHWEST NEBRASKA. ACTUALLY...BY LATE THURSDAY NIGHT MOST OF
THE SOUNDING IS ISOTHERMAL IN THE DENDRITIC GROWTH ZONE.
HOWEVER...AT THIS POINT THE UPPER LEVEL SYSTEM IS WELL PAST AND THE
AREA IS IN AN AREA OF SUBSIDENCE AND LIFT IS MINIMAL SO THERE IS
ENOUGH DISCONNECT BETWEEN THE FAVORABLE CONDITIONS TO LIMIT FROM
HEAVY SNOWS. COULD SEE A COUPLE INCHES...POSSIBLY UP TO 4 ON THE
PINE RIDGE. WILL PROBABLY SEE SOME LIGHT SNOW ACROSS THE REST OF
NORTHERN NEBRASKA...BUT ONSET WILL BE LATER IN THE DAY THURSDAY AND
WITH THE UPWARD FORCING MOSTLY GONE BY MIDNIGHT EXPECT JUST LIGHT
AMOUNTS. DIFFERENT CONCERN IS FREEZING DRIZZLE FOR CENTRAL CHERRY
COUNTY AND EASTWARD ON THURSDAY. THE LOWEST 2500FT BECOME SATURATED
BY 18Z THURSDAY ACCORDING TO SOUNDINGS AT KVTN...WHILE A DEEP DRY
MID LAYER MAY PROHIBIT SEEDER FEEDER MECHANISM FROM OCCURRING FOR A
FEW HOURS. THERE IS DECENT OMEGA IN THESE LOW LEVELS SO DID ADD
CHANCES FOR FREEZING DRIZZLE INTO THE FORECAST FOR THURSDAY.
WILL ALSO BE QUITE WINDY ON THURSDAY AND THURSDAY NIGHT BEHIND THE
COLD FRONT WHICH WILL DROP WIND CHILLS TO AROUND -10F BY FRIDAY
MORNING.
LOOKING INTO THE WEEKEND...THE UPPER LOW OVER THE SOUTHWEST WILL
MIGRATE ACROSS THE SOUTHERN PLAINS WHILE THE LOCAL AREA WILL SEE
ANOTHER SHORTWAVE TROUGH MOVE ACROSS THE AREA THROUGH THE NORTHERN
STREAM. THERE IS SOME DIFFERENCES ON TIMING OF THIS NEXT
SYSTEM...BUT SHOULD BE MOVING THROUGH SOMETIME SATURDAY NIGHT/SUNDAY.
DOESN/T LOOK LIKE MUCH FOR PRECIPITATION WITH THIS NEXT SYSTEM BUT
THERE IS POTENTIAL FOR ANOTHER PUSH OF ARCTIC AIR INTO THE AREA
BEHIND IT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1137 PM CST MON DEC 16 2013
OVER THE NEXT 24 HOURS...VFR CONDS ARE EXPECTED AT BOTH THE KVTN
AND KLBF TERMINALS. WINDS WILL BE FROM THE NORTHWEST AT UNDER 10
KTS OVERNIGHT TONIGHT...WITH A SHIFT IN WIND DIRECTION TO THE WEST
THEN SOUTHWEST THROUGH TUESDAY EVENING. SKIES WILL BE PARTLY TO
MOSTLY CLOUDY TONIGHT WITH CIGS AON 10000 FT AGL AT THE KVTN
TERMINAL...AND 20000 FT AGL AT THE KLBF TERMINAL. FOR
TUESDAY...CLEAR TO MOSTLY CLEAR SKIES ARE EXPECTED.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 AM EST WED DEC 17 2013
.SYNOPSIS...A POTENT UPPER LEVEL DISTURBANCE WILL DIG SOUTHEAST INTO
THE MID-ATLANTIC LATE THIS AFTERNOON AND EVENING...WHILE AN
ATTENDANT SURFACE LOW AND ASSOCIATED COLD FRONT TRACK QUICKLY EAST
ACROSS VIRGINIA AND THE CAROLINAS. MILD HIGH PRESSURE WILL BUILD
INTO THE REGION FROM THE SOUTHWEST TONIGHT AND WEDNESDAY...THEN
SHIFT OFFSHORE ON THURSDAY.
&&
.NEAR TERM /TONIGHT/...
AS OF 710 PM MONDAY...
THE LATEST WATER VAPOR IMAGERY SHOWED A WELL-DEFINED MID-LEVEL
SHORTWAVE MOVING TOWARD THE STATE FROM THE WEST...AND THIS WAVE WILL
MOVE ACROSS THE STATE THIS EVENING AND THROUGH THE EARLY PART OF THE
OVERNIGHT HOURS WITH AREAS OF MID- AND HIGH-LEVEL CLOUDS AHEAD OF
IT. THE LATEST RAP MID- AND UPPER-LEVEL RELATIVE HUMIDITY
FORECASTS...ALONG WITH THE HRRR WRF CLOUD COVER FORECAST...ARE
HANDLING THE BASIC COVERAGE AND ORIENTATION OF THE EXISTING CLOUDS
WELL...AND AS THE SHORTWAVE MOVES EAST THE CLOUDS...MOSTLY ALONG AND
NORTH OF ABOUT U.S. 64...WILL SHIFT EAST AS WELL. PATCHY HIGH CLOUDS
ARE LOCATED FARTHER UPSTREAM...AND IN THE WEST-TO-NORTHWEST FLOW
ALOFT SOME OF THESE SHOULD WORK THEIR WAY INTO THE NORTHWEST
PIEDMONT LATE TONIGHT. PARTLY CLOUDY THIS EVENING WITH PERIODS OF
MOSTLY CLEAR CONDITIONS OVERNIGHT BASICALLY ALONG AND NORTH OF U.S.
64...BECOMING PARTLY CLOUDY AGAIN LATE TOWARD THE TRIAD. SOUTH OF
ABOUT U.S. 64...MOSTLY CLEAR ON AVERAGE.
SURFACE DEW POINTS IN THE MID 30S TO NEAR 40 OVER A LARGE PART OF
CENTRAL NORTH CAROLINA...EXCEPT THE NORTHWEST PIEDMONT...HAVE
STARTED TO FALL OVER THE LAST HOUR OR TWO IN ACCORDANCE WITH THE RAP
FORECASTS AND MOS GUIDANCE. TEMPERATURES IN SOME AREAS HAVE SHOWN A
RAPID DECLINE...BUT OVERNIGHT THE SURFACE DEW POINTS ARE EXPECTED TO
STABILIZE AND THERE IS FORECAST A GRADUAL INCREASE IN 925MB WINDS AS
THE SURFACE HIGH MOVES OFF TO THE EAST...AND THE GRADIENT STARTS TO
TIGHTEN SOME. THE SURFACE FRONT TO OUR NORTH MAY MOVE A LITTLE
FARTHER NORTH LATE TONIGHT...AND THERE COULD BE JUST ENOUGH STIRRING
OF THE WIND OVERNIGHT AT TIMES TO KEEP TEMPERATURES FROM FALLING
WELL BELOW GUIDANCE. MINS ARE ALREADY FORECAST NEAREST THE COLDER
MAV GUIDANCE AND HAVE CONTINUED THAT FOR THIS FORECAST BASED ON
EXPECTED CLEARING AND THE PACE OF FALLING TEMPERATURES THUS FAR.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 240 PM MONDAY...
THE SURFACE LOW TRACKING EASTWARD THROUGH THE NORTHERN MID-ATLANTIC
STATES WILL EXIT OFFSHORE TUESDAY AFTERNOON...AND WILL DRAG A
SURFACE COLD FRONT THROUGH THE AREA TUESDAY EVENING. UNDER PARTLY TO
MOSTLY SUNNY SKIES...LOW-LEVEL SWLY WARM AIR ADVECTION PRIOR TO THE
ARRIVAL OF THE COLD FRONT WILL ALLOW THICKNESSES TO CLIMB ANOTHER 10
METERS WHICH SHOULD SUPPORT HIGHS IN THE MID 50S NORTH TO AROUND 60
SOUTH.
CAA IN THE WAKE OF THE COLD FRONTAL PASSAGE TUESDAY EVENING WILL
GOVERN OVERNIGHT LOWS...WITH LOW-LEVEL THICKNESSES PROGGED TO FALL
TO AROUND 1280 METERS...35 METERS BELOW NORMAL. OVERNIGHT LOWS IN
THE UPPER 20S NORTH TO LOWER/MID 30S SOUTHEAST.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 AM TUESDAY...
...RECORD WARMTH EXPECTED SATURDAY AND SUNDAY...
SEE THE CLIMATE SECTION BELOW FOR DAILY RECORD HIGHS FOR THE 21ST
AND 22ND OF DECEMBER.
STRONG UPPER RIDGING WILL SET UP OFF THE SE COAST FRI-SUN. THIS WILL
BLOCK THE COLD FRONT TO OUR WEST THROUGH LATE SUNDAY OR SUNDAY NIGHT
PER THE FAVORED AND SLOWER EC GUIDANCE. THIS IS ALSO WHEN THE CHANCE
OF RAIN IS EXPECTED.
UNTIL THEN... A GRADUAL WARMING TREND THURSDAY AND FRIDAY WITH
TEMPERATURES BECOMING ABOVE NORMAL BY THURSDAY WHEN HIGHS WILL REACH
THE LOWER TO MID 60S WITH MOSTLY SUNNY SKIES AND A SW BREEZE. FRIDAY
HIGHS SHOULD APPROACH 70 AND EVEN HIT 70 IN THE SANDHILLS.
BY SATURDAY... LOW CLOUDS SHOULD MIX OUT BY NOON MOST AREAS. THE
INCREASING LOW LEVEL FLOW SHOULD ALSO ALLOW TEMPERATURES TO SOAR
INTO THE LOWER TO MID 70S. IF THIS OCCURS... NEW DAILY RECORD HIGHS
WOULD BE LIKELY.
IT APPEARS THAT THE ONLY THING THAT MAY SLOW THE TEMPERATURES THIS
WEEKEND WOULD POTENTIALLY BE LOW CLOUDINESS IN THE S-SW FLOW
PATTERN. HOWEVER... IT APPEARS THAT THE NW PIEDMONT WOULD BE THE
MOST LIKELY AREA TO HAVE THE LOW CLOUDS LINGER MUCH OF THE DAY
SUNDAY. HOWEVER... THE COOLEST GUIDANCE STILL GIVES LOWER 70S AT
GREENSBORO AND MID 70S IN RALEIGH SUNDAY... WHICH WOULD BE RIGHT AT
THE RECORD DAILY RECORDS OF 71 AND 75.
BY LATE SUNDAY INTO MONDAY... INCREASING POP WITH THE ACTUAL COLD
FRONT EXPECTED TO PUSH SE THROUGH THE REGION MONDAY. TEMPS ON MONDAY
SHOULD COOL OFF DUE TO THE WIND SHIFT TO THE NE AND THE EXPECTED
RAINFALL.
BY TUESDAY... HIGHS SHOULD RETURN BACK INTO THE LOWER TO MID 50S
(NEAR NORMAL) AS A STRONG HIGH PRESSURE BUILDS DOWN THE EASTERN
SEABOARD.
THE OUTLOOK FOR NEXT WEEK... IS FOR MUCH COOLER TEMPERATURES WITH A
CHANCE OF COLD RAIN AGAIN MID WEEK WITH ADDITIONAL WAVES POSSIBLE
ALONG THE SE COAST.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 100 AM TUESDAY...
24-HR TAF PERIOD: THE LATEST MODEL GUIDANCE HAS TRENDED FURTHER
SOUTH WITH A POTENT UPPER LEVEL DISTURBANCE DIGGING SE INTO THE MID-
ATLANTIC TODAY/TONIGHT...ALONG WITH THE ATTENDANT CLIPPER LOW NOW
PROGGED TO TRACK EAST ACROSS THE VIRGINIAS. AS A RESULT...IT NOW
APPEARS THAT THERE WILL BE A NARROW WINDOW OF OPPORTUNITY FOR MVFR
CEILINGS AND ISOLD SHOWER ACTIVITY BETWEEN 00-06Z WED...PRIMARILY
ALONG AND NORTH OF HWY 64 (INT/GSO/RDU/RWI TERMINALS). OTHERWISE...
VFR CONDITIONS WILL PREVAIL. SW WINDS AT 5-10 KT THIS MORNING WILL
INCREASE TO 10-15 KT BY MID AFTERNOON WITH A POTENTIAL FOR GUSTS IN
THE 18-23 KT RANGE...ESPECIALLY AT THE FAY/RWI TERMINALS (MORE-SO
FAY) WHERE THE MSLP GRADIENT WILL BE TIGHTEST. WINDS WILL VEER TO
THE WNW/NW AT 10-15 KT BETWEEN 00-06Z WED AS A COLD FRONT ASSOC/W
THE CLIPPER LOW SWEEPS EAST ACROSS CENTRAL NC.
LOOKING AHEAD: VFR CONDITIONS WILL RULE WED/WED NIGHT IN THE WAKE OF
THE FRONT AS MILD HIGH PRESSURE BUILDS INTO THE REGION FROM THE
SOUTHWEST. HIGH PRESSURE WILL MOVE OFFSHORE BY LATE THU...SETTING UP
AN INCREASINGLY WARM/MOIST SOUTHERLY RETURN FLOW ACROSS THE
CAROLINAS THU-SAT. VFR CONDITIONS WILL LARGELY PREVAIL THROUGH THIS
PERIOD...THOUGH WITH AN INCREASING CHANCE OF IFR/LIFR CEILINGS
DURING THE EARLY MORNING HOURS FRI/SAT AND POSSIBLY A CHANCE OF
SHOWERS OVER THE WEEKEND. -VINCENT
&&
.CLIMATE...
DAILY RECORD HIGHS FOR SATURDAY AND SUNDAY... DECEMBER 21 AND 22
ARE...
RALEIGH/DURHAM...
DECEMBER 21... 71 DEGREES... SET IN 1967
DECEMBER 22... 75 DEGREES... SET IN 1967
GREENSBORO...
DECEMBER 21... 66 DEGREES... SET IN 1923
DECEMBER 22... 71 DEGREES... SET IN 1923
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...CBL
LONG TERM...BADGETT
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
113 AM EST WED DEC 17 2013
.SYNOPSIS...A POTENT UPPER LEVEL DISTURBANCE WILL DIG SOUTHEAST INTO
THE MID-ATLANTIC LATE THIS AFTERNOON AND EVENING...WHILE AN
ATTENDANT SURFACE LOW AND ASSOCIATED COLD FRONT TRACK QUICKLY EAST
ACROSS VIRGINIA AND THE CAROLINAS. MILD HIGH PRESSURE WILL BUILD
INTO THE REGION FROM THE SOUTHWEST TONIGHT AND WEDNESDAY...THEN
SHIFT OFFSHORE ON THURSDAY.
&&
.NEAR TERM /TONIGHT/...
AS OF 710 PM MONDAY...
THE LATEST WATER VAPOR IMAGERY SHOWED A WELL-DEFINED MID-LEVEL
SHORTWAVE MOVING TOWARD THE STATE FROM THE WEST...AND THIS WAVE WILL
MOVE ACROSS THE STATE THIS EVENING AND THROUGH THE EARLY PART OF THE
OVERNIGHT HOURS WITH AREAS OF MID- AND HIGH-LEVEL CLOUDS AHEAD OF
IT. THE LATEST RAP MID- AND UPPER-LEVEL RELATIVE HUMIDITY
FORECASTS...ALONG WITH THE HRRR WRF CLOUD COVER FORECAST...ARE
HANDLING THE BASIC COVERAGE AND ORIENTATION OF THE EXISTING CLOUDS
WELL...AND AS THE SHORTWAVE MOVES EAST THE CLOUDS...MOSTLY ALONG AND
NORTH OF ABOUT U.S. 64...WILL SHIFT EAST AS WELL. PATCHY HIGH CLOUDS
ARE LOCATED FARTHER UPSTREAM...AND IN THE WEST-TO-NORTHWEST FLOW
ALOFT SOME OF THESE SHOULD WORK THEIR WAY INTO THE NORTHWEST
PIEDMONT LATE TONIGHT. PARTLY CLOUDY THIS EVENING WITH PERIODS OF
MOSTLY CLEAR CONDITIONS OVERNIGHT BASICALLY ALONG AND NORTH OF U.S.
64...BECOMING PARTLY CLOUDY AGAIN LATE TOWARD THE TRIAD. SOUTH OF
ABOUT U.S. 64...MOSTLY CLEAR ON AVERAGE.
SURFACE DEW POINTS IN THE MID 30S TO NEAR 40 OVER A LARGE PART OF
CENTRAL NORTH CAROLINA...EXCEPT THE NORTHWEST PIEDMONT...HAVE
STARTED TO FALL OVER THE LAST HOUR OR TWO IN ACCORDANCE WITH THE RAP
FORECASTS AND MOS GUIDANCE. TEMPERATURES IN SOME AREAS HAVE SHOWN A
RAPID DECLINE...BUT OVERNIGHT THE SURFACE DEW POINTS ARE EXPECTED TO
STABILIZE AND THERE IS FORECAST A GRADUAL INCREASE IN 925MB WINDS AS
THE SURFACE HIGH MOVES OFF TO THE EAST...AND THE GRADIENT STARTS TO
TIGHTEN SOME. THE SURFACE FRONT TO OUR NORTH MAY MOVE A LITTLE
FARTHER NORTH LATE TONIGHT...AND THERE COULD BE JUST ENOUGH STIRRING
OF THE WIND OVERNIGHT AT TIMES TO KEEP TEMPERATURES FROM FALLING
WELL BELOW GUIDANCE. MINS ARE ALREADY FORECAST NEAREST THE COLDER
MAV GUIDANCE AND HAVE CONTINUED THAT FOR THIS FORECAST BASED ON
EXPECTED CLEARING AND THE PACE OF FALLING TEMPERATURES THUS FAR.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 240 PM MONDAY...
THE SURFACE LOW TRACKING EASTWARD THROUGH THE NORTHERN MID-ATLANTIC
STATES WILL EXIT OFFSHORE TUESDAY AFTERNOON...AND WILL DRAG A
SURFACE COLD FRONT THROUGH THE AREA TUESDAY EVENING. UNDER PARTLY TO
MOSTLY SUNNY SKIES...LOW-LEVEL SWLY WARM AIR ADVECTION PRIOR TO THE
ARRIVAL OF THE COLD FRONT WILL ALLOW THICKNESSES TO CLIMB ANOTHER 10
METERS WHICH SHOULD SUPPORT HIGHS IN THE MID 50S NORTH TO AROUND 60
SOUTH.
CAA IN THE WAKE OF THE COLD FRONTAL PASSAGE TUESDAY EVENING WILL
GOVERN OVERNIGHT LOWS...WITH LOW-LEVEL THICKNESSES PROGGED TO FALL
TO AROUND 1280 METERS...35 METERS BELOW NORMAL. OVERNIGHT LOWS IN
THE UPPER 20S NORTH TO LOWER/MID 30S SOUTHEAST.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...
A PROGRESSIVE NORTHERN STREAM SHORT WAVE TROUGH EXITS THE MID
ATLANTIC EARLY ON WEDNESDAY WITH THE FLOW ALOFT BECOMING MORE
WESTERLY ON THURSDAY. A DRY ATMOSPHERE WITH PW VALUES GENERALLY LESS
THAN 0.3 INCHES PROVIDES A HIGH CONFIDENCE FORECAST OF DRY WEATHER
WITH FEW CLOUDS. SLIGHTLY BELOW NORMAL TEMPS ON WEDNESDAY WITH HIGHS
AROUND 50 WILL WARM INTO THE MID 50S TO NEAR 60 BY THURSDAY. LOWS
THURSDAY MORNING WILL RANGE IN THE UPPER 20S TO LOWER 30S.
AN AMPLIFYING TROUGH DIVES SOUTH ALONG THE PACIFIC COAST ON FRIDAY
AS THE FLOW ALOFT OVER CENTRAL NC BECOMES MORE SOUTHWESTERLY. AT THE
SAME TIME SURFACE HIGH PRESSURE OVER THE CAROLINAS SHIFTS OFFSHORE
AND A LOW LEVEL RETURN FLOW DEVELOPS. THE RETURN FLOW WILL ALLOW
SHALLOW MOISTURE TO SPREAD INTO THE REGION...MODERATING MORNING LOWS
ON FRIDAY (IN THE 40-45 RANGE) AND PROVING THE POTENTIAL FOR SOME
MORNING STRATUS THAT WILL MIX INTO SOME AFTERNOON CUMULIFORM CLOUDS
UNDER A CANOPY OF CIRRUS ALOFT. COULD BE AN ISOLATED SHOWER IN THE
WARM SOUTHERLY FLOW BUT THIS PATTERN IS SOMETIMES SLOW TO EVOLVE AND
COVERAGE WILL LIKELY BE LIMITED. GIVEN LOW CONFIDENCE IN
POPS...PREFER TO OMIT RAIN CHANCES ON FRIDAY FOR NOW. HIGHS FRIDAY
AFTERNOON SHOULD CLIMB INTO THE 60S TO NEAR 70 WITH LOWS FRIDAY
NIGHT IN THE LOWER TO MID 50S.
THE PACIFIC TROUGH CLOSES OFF LATE FRIDAY INTO EARLY SATURDAY IN
MEXICO SOUTH OF AZ/NM AND THEN LIFTS NORTHEAST ACROSS THE
CENTRAL/EASTERN U.S. OVER THE WEEKEND INTO MONDAY. THE MAIN ENERGY
WITH THE SYSTEM SLOWLY SHEARS OUT OVER THE MS VALLEY INTO THE
WESTERN OH VALLEY AND GREAT LAKES WITH THE ATTENDANT SURFACE LOW
REMAINING WEST OF THE APPALACHIANS. THE TRAILING COLD FRONT IS LEFT
DANGLING SOUTH OF THE DEPARTING STRONGER FLOW AND SETS UP PARALLEL
TO THE FLOW ALOFT. THIS TYPE OF PATTERN TYPICALLY RESULTS IN A
SLOWER PASSAGE OF THE COLD FRONT AND LESS ROBUST PRECIPITATION
CHANCES. WPC GUIDANCE PREFERS A SLOWER EC ENS MEAN AND HAVE REDUCED
POPS SLIGHTLY BUT MORE SIGNIFICANTLY DELAYED POPS A BIT FOCUSING ON
LATER MONDAY FOR THE BEST CHANCE OF SHOWERS. -BLAES
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 100 AM TUESDAY...
24-HR TAF PERIOD: THE LATEST MODEL GUIDANCE HAS TRENDED FURTHER
SOUTH WITH A POTENT UPPER LEVEL DISTURBANCE DIGGING SE INTO THE MID-
ATLANTIC TODAY/TONIGHT...ALONG WITH THE ATTENDANT CLIPPER LOW NOW
PROGGED TO TRACK EAST ACROSS THE VIRGINIAS. AS A RESULT...IT NOW
APPEARS THAT THERE WILL BE A NARROW WINDOW OF OPPORTUNITY FOR MVFR
CEILINGS AND ISOLD SHOWER ACTIVITY BETWEEN 00-06Z WED...PRIMARILY
ALONG AND NORTH OF HWY 64 (INT/GSO/RDU/RWI TERMINALS). OTHERWISE...
VFR CONDITIONS WILL PREVAIL. SW WINDS AT 5-10 KT THIS MORNING WILL
INCREASE TO 10-15 KT BY MID AFTERNOON WITH A POTENTIAL FOR GUSTS IN
THE 18-23 KT RANGE...ESPECIALLY AT THE FAY/RWI TERMINALS (MORE-SO
FAY) WHERE THE MSLP GRADIENT WILL BE TIGHTEST. WINDS WILL VEER TO
THE WNW/NW AT 10-15 KT BETWEEN 00-06Z WED AS A COLD FRONT ASSOC/W
THE CLIPPER LOW SWEEPS EAST ACROSS CENTRAL NC.
LOOKING AHEAD: VFR CONDITIONS WILL RULE WED/WED NIGHT IN THE WAKE OF
THE FRONT AS MILD HIGH PRESSURE BUILDS INTO THE REGION FROM THE
SOUTHWEST. HIGH PRESSURE WILL MOVE OFFSHORE BY LATE THU...SETTING UP
AN INCREASINGLY WARM/MOIST SOUTHERLY RETURN FLOW ACROSS THE
CAROLINAS THU-SAT. VFR CONDITIONS WILL LARGELY PREVAIL THROUGH THIS
PERIOD...THOUGH WITH AN INCREASING CHANCE OF IFR/LIFR CEILINGS
DURING THE EARLY MORNING HOURS FRI/SAT AND POSSIBLY A CHANCE OF
SHOWERS OVER THE WEEKEND. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...DJF
SHORT TERM...CBL
LONG TERM...BLAES
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
226 AM CST TUE DEC 17 2013
.UPDATE...
ISSUED AT 225 AM CST TUE DEC 17 2013
QUICK UPDATE TO ISSUE A WIND ADVISORY FROM THE TURTLE MOUNTAINS
SOUTH INTO THE NORTHERN PORTION OF THE JAMES RIVER VALLEY. EXPECT
SUSTAINED WINDS TO 35 MPH WITH GUSTS TO 45 MPH. UPDATES TO TEXT
PRODUCTS FORTHCOMING.
UPDATE ISSUED AT 1154 PM CST MON DEC 16 2013
LATEST WATER VAPOR IMAGERY SHOWS NORTHWEST FLOW INTO NORTH DAKOTA
WITH ONE SHORTWAVE EXITING THE SOUTHWEST...WITH ANOTHER SHORTWAVE
NEAR THE TURTLE MOUNTAINS MOVING SOUTHEAST WITH TIME. LOCAL/REGIONAL
RADAR SHOWS ISOLATED PRECIPITATION AREAS WHICH CONTINUE TO MOVE
SOUTHEAST AND WEAKEN. THUS HAVE MAINTAINED THE TREND OF ENDING ANY
MEASURABLE PRECIPITATION AMOUNTS ACROSS THE SOUTHWEST AND JAMES
RIVER VALLEY OVER THE NEXT ONE TO THREE HOURS. WINDS WILL REMAIN
GUSTY OVERNIGHT...ESPECIALLY NORTH AND EAST CENTRAL. WILL KEEP THE
SPECIAL WEATHER STATEMENT GOING UNTIL 130 AM CST MENTIONING ICY
TRAVEL. REST OF FORECAST LOOKS IN GOOD SHAPE OVERNIGHT.
UPDATE ISSUED AT 932 PM CST MON DEC 16 2013
MAIN UPDATE THIS EVENING WAS TO BUMP UP POPS THROUGH MIDNIGHT OVER
THE SOUTHWEST. BAND OF LIGHT SNOW INDUCED BY A SHORTWAVE IN
NORTHWEST UPPER FLOW HAD DEVELOPED FROM NEAR BEACH SOUTHWEST TO
AROUND HETTINGER. THIS BAND SHOULD MOVE QUICKLY SOUTHEAST BUT WILL
PRODUCE PERIODS OF LIGHT TO MODERATE SNOW. WINDS HAVE DIMINISHED
OVER THE SOUTHWEST SO NOT MUCH PROBLEM WITH BLOWING SNOW HERE.
THINK SNOW WILL BE PRETTY MUCH OUT OF THE AREA AROUND MIDNIGHT.
ELSEWHERE...STRONG WINDS CONTINUE OVER CENTRAL NORTH DAKOTA WITH
GUSTS TO 35 MPH AT MINOT AND BISMARCK EAST TO RUGBY...CARRINGTON
AND JAMESTOWN. EXPECT AREAS OF BLOWING AND DRIFTING SNOW TO
CONTINUE THROUGH LATE TONIGHT. ISOLATED SNOW SHOWERS FROM
CARRINGTON TO JAMESTOWN WILL MOVE QUICKLY SOUTHEAST...HOWEVER A
BRIEF FLURRY OR SNOW SHOWER CANNOT BE COMPLETELY RULED OUT MOST
ANYWHERE THROUGH LATE THIS EVENING.
UPDATE ISSUED AT 644 PM CST MON DEC 16 2013
LATEST RADAR LOOP IS STILL SHOWING SOME LIGHT REFLECTIVITIES
ACROSS WESTERN AND CENTRAL NORTH DAKOTA...BUT LITTLE IN THE WAY OF
SURFACE REPORTS VIA OBSERVATIONS OR WEATHER CAMERAS. STILL KEPT
SOME POPS IN THE SOUTHWEST...HIGHEST EARLY THIS EVENING AND
TAPERING THROUGH LATE EVENING. ALSO SOME SNOW SHOWERS OVER ROLETTE
COUNTY SO BUMPED UP POPS OVER NORTHEAST ROLETTE FOR A COUPLE
HOURS. RAISED SKY COVER OVER THE SOUTHWEST AND GENERALLY BUMPED UP
SKY ACROSS THE AREA THROUGH THE EVENING AS THERE ARE QUITE A BIT
OF MID AND HIGH LEVEL CLOUDS TRAVERSING THE AREA IN NORTHWEST
FLOW.
RECEIVED QUITE A FEW RESPONSES VIA SOCIAL MEDIA ABOUT THE
SLIPPERY ROADS ACROSS MAINLY THE NORTH. WILL EXTEND THE SPS FOR
ICY CONDITIONS THROUGH THE EVENING HOURS AS WE WILL REMAIN BREEZY
AND TEMPERATURES DROP BELOW FREEZING.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY AFTERNOON)
ISSUED AT 334 PM CST MON DEC 16 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE AREAS OF
BLOWING/DRIFTING SNOW RESULTING IN POSSIBLE ICY ROADS/BLACK ICE
ACROSS THE NORTH THROUGH THIS EVENING...AND A CHANCE OF LIGHT SNOW
THIS AFTERNOON AND EVENING WEST TO EAST.
CURRENTLY...STRONG NORTHWEST FLOW ALOFT WITH A SHARP RIDGE OFF
THE WEST COAST AND A BROAD LONG WAVE TROUGH OVER THE EASTERN
UNITED STATES. UPPER LEVEL JET STREAM EXTENDS FROM THE TOP OF THE
RIDGE OVER ALASKA...SOUTHEAST INTO THE NORTHERN HIGH PLAINS OF
MT/WY. STRONG PRESSURE GRADIENT CONTINUES TO DEVELOP ACROSS WEST
AND CENTRAL NORTH DAKOTA WEST OF A SURFACE TROUGH OVER FAR WESTERN
MINNESOTA. GRADIENT FORCING WILL INCREASE THROUGHOUT THE DAY AND
INTO THIS EVENING AS THE TROUGH REMAINS QUASI-STATIONARY AND AS A
SURFACE HIGH BUILDS OFF TO OUR WEST CENTERED OVER THE NORTHEASTERN
SNAKE RIVER VALLEY OF EASTERN IDAHO.
MODELS EARLIER WERE LOOKING LIKE THEY WERE TRENDING TOWARDS A
CONSENSUS REGARDING PRECIPITATION CHANCES THIS AFTERNOON AND
EVENING. NOW NOT SO MUCH. MOISTURE IS HAVING A HARD TIME REACHING
THE GROUND ACROSS MY WEST CENTRAL. WEB CAMS OVER SOUTHWEST NORTH
DAKOTA DEFINITELY SHOWING SNOWFALL ALTHOUGH MOSTLY MELTING ON THE
ROAD SURFACES. BOWMAN RADAR STILL LIT UP...AND BAKER MT STILL
REPORTING SNOW. THE 12Z ECMWF AND LATEST RAP SEEM TO BE CAPTURING
REALITY THE BEST VERSUS OTHER GUIDANCE. LEANED IN THEIR DIRECTION
WITH LINGERING LIGHT PRECIPITATION SOUTHWEST NOW THROUGH THIS
EVENING...AND ANOTHER AREA OF LIGHT PRECIPITATION MOVING SOUTHEAST
OVER MY EASTERN COUNTIES LATE AFTERNOON AND EVENING. THIS AREA
CURRENTLY SHOWING UP ON RADAR OVER SOUTHEAST SK/SOUTHWEST
MANITOBA.
THE INCREASING PRESSURE GRADIENT WILL SEE WINDS INCREASE TO JUST
BELOW WIND ADVISORY CRITERIA MOST LOCATIONS NOW THROUGH THE
EVENING HOURS...BEFORE WINDING DOWN AFTER 06Z. AT THIS TIME WINDS
ARE SUSTAINED AT 15-25 MPH MOST LOCATIONS...WITH GUSTS AS HIGH AS
35 MPH REPORTED. ROAD SFC TEMPS REMAIN AT OR BELOW FREEZING NORTH
AND ABOVE 32F SOUTH. AIR TEMPERATURES MAINLY IN THE LOWER TO MID
30S. WIND DRIVEN SNOW IS STILL EXPECTED TO CREATE HAZARDOUS
TRAVEL...ESPECIALLY WHEN WET ROADS REFREEZE AND/OR BLOWING SNOW
STARTS TO STICK THIS AFTERNOON. WILL MAINTAIN THE SPECIAL WEATHER
STATEMENT AS IS FOR NOW AND LET THE EVENING CREW DECIDE ITS FATE
AT THE 7PM UPDATE PERIOD.
TUESDAY MORNING/AFTERNOON LOOK TO BE RELATIVELY QUIET WITH PARTLY
CLOUDY SKIES AND DRY CONDITIONS. A WARM FRONT MOVING INTO
SOUTHEAST MONTANA WILL SEE TEMPERATURES WARMING TO NEAR 40 OVER MY
FAR SOUTHWEST CORNER. SHARP TEMPERATURE GRADIENT WITH HIGHS AROUND
15 ABOVE FOR THE TURTLE MOUNTAINS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 334 PM CST MON DEC 16 2013
THE MAIN FORECAST ISSUE IS SNOWFALL AMOUNTS AND COVERAGE WITH THE
MID WEEK STORM.
A LOW PRESSURE CLIPPER SYSTEM IS FORECAST TO DEVELOP TUESDAY OVER
ALBERTA AND MOVE EAST/SOUTHEAST TOWARDS NORTH DAKOTA TUESDAY NIGHT.
WINDS ACROSS THE FORECAST AREA SHOULD START OUT SOUTHERLY EARLY
TUESDAY EVENING...BECOMING WEST DURING THE EVENING/NIGHT WITH WARM
ADVECTION AS NORTH DAKOTA REMAINS IN THE WARM SECTOR OF THE SYSTEM.
ON WEDNESDAY THE CLIPPER LOW DEVELOPS INTO MORE OF A COLD FRONT IN
NATURE...MOVING SOUTH ACROSS THE STATE. IT APPEARS THAT THE MARKED
COLD ADVECTION WITH THE ARCTIC AIR BEGINS WEDNESDAY AROUND NOON IN
THE NORTH AND DURING THE AFTERNOON FARTHER SOUTH. HIGHS WEDNESDAY
SHOULD RANGE FROM THE UPPER TEENS/MID 20S NORTH TO THE UPPER 20S/30S
SOUTH. KEPT A SLIGHT CHANCE OF LIGHT SNOW IN THE NORTHWEST AND NORTH
CENTRAL NORTH DAKOTA ALONG THE ARCTIC COLD FRONT.
MODEL AGREEMENT CONTINUES TO IMPROVE REGARDING THE MAIN SYNOPTIC
FEATURES OF THE UPPER LEVEL TROUGH AND VORT ENERGY IMPULSES...AS
WELL AS THE POSITION OF THE COLD FRONT AND ARCTIC HIGH PRESSURE
SYSTEM. THE UPPER LEVEL TROUGH MOVES ACROSS NORTH DAKOTA
THURSDAY/THURSDAY EVENING. MEANWHILE THE SURFACE ARCTIC HIGH DIVES
SOUTH FROM ALBERTA INTO MONTANA WEDNESDAY NIGHT/THURSDAY. IN NORTH
DAKOTA...THE ARCTIC COLD FRONT MOVES SOUTH ACROSS THE STATE
WEDNESDAY AFTERNOON/EVENING WITH COLD ADVECTION CONTINUING THROUGH
THE DAY THURSDAY.
THE PLACEMENT OF SNOWFALL LOOKS TO BE HIGHEST IN MONTANA...BUT SNOW
ACCUMULATIONS ALONG THE NORTH DAKOTA/SOUTH DAKOTA BORDER SHOULD BE
IN THE 2-4 INCH RANGE. FOR WESTERN AND CENTRAL NORTH DAKOTA THE BULK
OF THE SNOWFALL SHOULD BEGIN WEDNESDAY NIGHT IN THE WEST...AND
EXPAND INTO CENTRAL NORTH DAKOTA AFTER MIDNIGHT WEDNESDAY
NIGHT/DAYBREAK THURSDAY MORNING...CONTINUE FOR MUCH OF THE
DAY THURSDAY...BEFORE TAPERING OFF IN THE JAMES RIVER VALLEY
THURSDAY EVENING.
VERY COLD AIR WILL ACCOMPANY THIS STORM SYSTEM WEDNESDAY NIGHT
THROUGH SATURDAY. SOME AREAS...ESPECIALLY THE NORTH...MAY HIT WIND
CHILL ADVISORY CRITERIA WEDNESDAY NIGHT AND THURSDAY NIGHT.
THE UPPER LEVEL PATTERN THROUGH THE WEEKEND CONTINUES NORTHWEST FLOW
ALOFT WITH A LARGE HUDSON BAY LOW IN PLACE. TOWARDS THE BEGINNING OF
NEXT WEEK THE MODELS ARE HINTING AT A MORE PROGRESSIVE PATTERN WITH
A WESTERN RIDGE BUILDING AND PUSHING THE HUDSON BAY LOW EASTWARD. NO
BIG WARM-UPS BUT NO BIG ARCTIC OUTBREAKS EITHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1154 PM CST MON DEC 16 2013
VFR CIGS/VSBYS NEXT 24HR. GUSTY WEST TO NORTHWEST WINDS OF 20KT TO
30KT WILL DECREASE TO AROUND 15KT BETWEEN 12Z AND 15Z TUESDAY.
OVERALL EXPECT MID LEVEL (8KFT-10KFT) SCT/BKN CONDITIONS AS
ANOTHER WARM FRONT APPROACHES TUESDAY AFTERNOON AND EVENING.
HOWEVER NO PRECIPITATION IS EXPECTED WITH IT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 AM CST THIS MORNING FOR NDZ004-005-012-013-
023-025-037.
&&
$$
UPDATE...KS
SHORT TERM...NH
LONG TERM...JV
AVIATION...KS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1148 PM CST MON DEC 16 2013
.UPDATE...
ISSUED AT 1148 PM CST MON DEC 16 2013
CURRENT FCST APPEARS TO BE ON TRACK WITH SNOW SHOWERS NOW ENTERING
FAR EASTERN EDGE OF RADAR COVERAGE...HOWEVER BJI REPORTING LIGHT
SNOW. MAY ACTUALLY END AN HOUR EARLIER THAN CURRENT GRIDS SHOW.
DID USE THE NAM H850-H700 RH FIELD TO FINE TUNE SKY COVER TONIGHT.
THERE IS A 5K FT DEC OVER PORTIONS OF MANITOBA THAT WILL ROTATE
DOWN AND CLIP NORTHEASTERN PORTIONS OF CWA. HAVE KEPT SCT SHSN IN
THE FCST AFT 09Z AS WINNIPEG AND SURROUNDING AREAS ARE RECEIVING
SOME LIGHT SNOW. CONTINUED LAPS TRENDS FOR OVERNIGHT LOWS.
UPDATE ISSUED AT 930 PM CST MON DEC 16 2013
CURRENT RADAR SHOWING SNOW SHOWERS HAVE CLEARED MOST OF EASTERN ND
WITH EXCEPTION OF A SMALLER BATCH AROUND AND NORTH OF VALLEY CITY.
AS PER RUC...APPEARS SHOWERS ARE INTENSIFY SLIGHTLY SO KEPT SNOW
TOTALS IN THE HALF TO ONE INCH RANGE DESPITE RECEIVING VERY LITTLE
HERE IN GRAND FORKS. MAY SEE A LITTLE BETTER ACCUMULATION FROM
FOSSTON DOWN THROUGH PARK RAPIDS. ADJUSTED NORTHWARD THE LIKELY
POPS BASED ON LATEST TRENDS AND BEGAN LOWERING/REMOVING EARLIER
THE POPS WEST OF THE RIVER. RUC CONTINUES TO BRING A SECOND ROUND
OF LIGHT SHOWERS TO MY FAR NORTHEAST AND DID BRING IN SCATTERED
SHOWERS AFT 09Z FOR ROSEAU/LAKE OF THE WOODS. ALSO PUT PATCHY BLOWING
SNOW IN GRIDS FOR MOST OF NORTHEASTERN ND WEST OF THE VALLEY AS
WINDS IN DVL ARE GUSTING TO AROUND 32 KTS AND HAVE SEEN VSBYS GO
DOWN TO 3 MILES.
UPDATE ISSUED AT 648 PM CST MON DEC 16 2013
CHANGE OVER TO VCP 31 HELPING DETECT SOME SNOW SHOWERS MOVING
THROUGH THE NORTHEASTERN ND TO THE SOUTHEAST. SHOULD ARRIVE AT
GRAND FORKS OVER NEXT COUPLE OF HOURS AND PROCEED ON DOWN TO THE
DETROIT LAKES AREA AFTER MID EVENING. SOME WEAKER RETURNS OVER
NORTHERN VALLEY APPEAR TO BE MID LEVEL CLOUDS PER HALLOCK METAR.
DID INCREASE POPS HIGH CHANCE / SCATTERED COVERAGE THROUGH MID
EVENING THEN LIKELIES FOR THE LATE EVENING...EXPECTING THEM TO
INTENSIFY A BIT AS THEY ENTER WESTERN MN. DO EXPECT SHOWERS TO BE
THROUGH AREA BY 06Z BUT WILL KEEP INHERITED POPS AFTER MIDNIGHT
UNTIL NEW NAM DATA COMES IN. LAPS HAS A DECENT HANDLE ON TEMP
TRENDS...INCREASING FROM WEST TO EAST AS WESTERLY FLOW
CONTINUES...AND HAVE ADJUSTED HOURLIES THROUGH MIDNIGHT PER THE
LAPS. TEMPS STILL EXPECTED TO BE QUITE A BIT CHILLIER OVER THE
EAST VS THE BALMY WEST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 331 PM CST MON DEC 16 2013
AS EXPECTED WEST WINDS HAVE ARRIVED WITH TEMPS NR 30 IN ERN ND AND
THE RRV WITH WARMER AIR LAST TO ARRIVE IN NORTHERN MN. UPPER LOW
OVER NORTHWESTERN ONTARIO WILL TAP INTO SOME COLDER AIR IN
NORTHEASTERN MANITOBA TONIGHT AND BRING SOUTH SOME COLDER 850 MB
AIR INTO NW MN/FAR NE ND AFTER MIDNIGHT. SO WHILE THIS EVENING
WILL REMAIN MILD EXPECT A DECENT COOL DOWN AFTER 06Z. A SHORT WAVE
FROM SOUTHWESTERN SASK INTO SOUTH DAKOTA WILL BRING SOME - SN TO
ERN MT/SW ND INTO PARTS OF NRN SD/SRN MN TONIGHT. MORE SPOTTY LIGHT
SNOWS REST OF THE AREA AS A WEAKER SHORT WAVE MOVES SOUTHEAST
ACROSS SOUTHEAST SASK INTO THE RED RIVER VALLEY.
TUESDAY WILL SEE HIGH PRESSURE RIDGE BUILD IN AND SHOULD SEE A
FAIR AMOUNT OF SUN WITH HIGHS QUITE A BIT COLDER IN THE TEENS OR
LOWER 20S. COLD TUESDAY NIGHT IN NW MN WITH LOWS A BIT BELOW
ZERO....BUT CLOUDS MOVING IN IN WARM ADV WILL MEAN NOT AS COLD IN
ERN ND.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 331 PM CST MON DEC 16 2013
WEDNESDAY WILL SEE LOW PRESSURE MOVE NORTH OF THE BORDER. SOME
WARM ADV -SN MAY IMPACT LAKE OF THE WOODS....BUT MOSTLY NORTH OF
THE BORDER. OTHERWISE 850 MB TEMPS ACTUALLY WARMER WED THAN TODAY
WITH TEMPS IN THE ZERO NORTH TO +4C RANGE BUT WINDS LIGHTER AND
MORE SOUTHERLY AND THUS NOT QUITE THE WARM WIND. BUT STILL EXPECT
20S FOR MANY AREAS.
COLDER AIR WILL BEGIN TO DROP SOUTH BEHIND THE CANADIAN LOW LATE
WED NIGHT AND THEN PUSH SOUTH QUICKLY THURSDAY. NEXT SYSTEM WILL
MOVE EAST THRU SOUTH DAKOTA INTO SOUTHERN MN THURSDAY AFTN
SPREADING SOME SNOW ALONG THE SD/ND BORDER.
FOR THU NIGHT THE MODELS REMAIN IN GOOD AGREEMENT IN DEPICTING A
SHIFT WAVE SHIFTING INTO MN. WILL LINGER LIGHT SNOW CHANCES MAINLY
ALONG AND SOUTH OF THE HIGHWAY 2 CORRIDOR. 500MB FLOW THEN SHIFTS
BACK TO THE NORTHWEST WITH SFC HIGH PRESSURE FOR FRI. STILL NOT
LOOKING LIKE MUCH WEATHER WISE FRI NIGHT INTO SAT WITH MOST LIGHT
SNOW STAYING NORTH OF THE CANADIAN BORDER. BY SAT NIGHT INTO SUN
HIGH PRESSURE MOVES BACK IN WITH SOME CHILLY AIR ONCE AGAIN. LARGER
MODEL DIFFERENCES COME INTO PLAY BY MONDAY SO CONFIDENCE DROPS
CONSIDERABLY. GUIDANCE TEMPS SHOWING MONDAY HIGHS QUITE A BIT COOLER
THAN THE PRIOR MODEL RUN. WITH THE LOW CONFIDENCE WILL RUN WITH THE
GUIDANCE OUTPUT FOR MONDAY AND SEE WHAT LATER RUNS HAVE IN STORE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1148 PM CST MON DEC 16 2013
TVF SHOULD SCT OUT OVER NEXT HOUR AND BJI BY AROUND 09Z BEFORE VFR
DECK SINKS INTO NW MN AROUND 10Z. CIGS HAVE BEEN IN THE 3K TO 5K
RANGE WITH LIGHT SNOW...HOWEVER THINK THEY WILL CONTINUE TO SINK
AND BE MVFR BEFORE REACHING BJI EARLY TUE AM. WILL KEEP TVF VFR
BUT GO MVFR FOR AM HOURS AT BJI. SHOULD SEE GRADUAL CLEARING FROM
WEST TO EAST TOMORROW...WITH MORE VFR CIGS MOVING IN AFT 03Z WED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...RIDDLE
LONG TERM...GODON/RIDDLE
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1140 PM CST MON DEC 16 2013
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 341 PM CST MON DEC 16 2013
LATEST WATER VAPOR SATELLITE IMAGERY SHOWING UPPER LEVEL TROUGH OVER
EASTERN HALF OF THE UNITED STATES AND SEVERAL WEAK SHORTWAVE TROUGHS
EMBEDDED IN THE NORTHWEST FLOW ALOFT FROM THE CANADIAN ROCKIES INTO
THE GREAT LAKES REGION. FIRST IMPULSE AFFECTING THE FORECAST AREA
TODAY IS PRODUCING BRIEF MODERATE HEAVY SNOW BANDS...THIS IS IN
RESPONSE TO STRONG ISENTROPIC LIFT AT 285K SURFACE AND QG FORCING
AT 850-700MB LAYER
THE LATEST 16.12Z GFS/NAM ARE IN GOOD AGREEMENT IN MOVING NEXT
IMPULSE FROM THE SOUTHERN CANADIAN PLAINS INTO THE FORECAST AREA
TONIGHT. THE 16.12Z GFS/NAM BEGIN TO DIVERGE SIGNIFICANTLY ON
PLACEMENT AND MOVEMENT OF SURFACE FRONT/SURGE OF WARMER AIR ALOFT
ADVECTING INTO THE REGION AFTER 12Z WEDNESDAY...WHERE THE NAM IS
MUCH MORE PROGRESSIVE WITH THE WARMER AIR THAN THE GFS. THIS WILL
HAVE IMPACTS ON PRECIPITATION TYPES ACROSS THE FORECAST AREA
THURSDAY.
TONIGHT...BOTH THE 16.12Z GFS/NAM SHOWING STRONG ISENTROPIC LIFT AT
285K SURFACE AND STRONG PV ADVECTION AT 500-300MB LAYER IN
ASSOCIATION WITH NEXT SHORTWAVE TROUGH MOVING OVER FORECAST
AREA...MAINLY AFTER 03Z TUESDAY. THE GFS/NAM SUGGEST THE VERTICAL
MOTION IS AT OR AROUND THE DENDRITIC GROWTH ZONE...HOWEVER...WITH
THE LIFT AND FORCING MOVING ACROSS THE FORECAST AREA QUICKLY.
SNOWFALL AMOUNTS SHOULD RANGE FROM AROUND A HALF OF AN INCH
ACROSS NORTHEAST IOWA TO AROUND TWO INCHES ACROSS CENTRAL
WISCONSIN.
ALONG WITH THE FRESH SNOW...SURFACE PRESSURE GRADIENT TIGHTENS ON
THE BACKSIDE OF THE SHORTWAVE TROUGH AFTER 06Z TUESDAY. THIS WILL
INCREASE WINDS ACROSS THE FORECAST AREA INTO 10 TO 20 KNOTS RANGE AND
GUSTS UP TO 20 TO 27 KNOTS. THIS WILL CREATE SOME AREAS/PATCHY
BLOWING SNOW MAINLY OVER THE HIGHER TERRAIN AND OPEN AREAS OF
SOUTHEAST MINNESOTA AND NORTHEAST IOWA INTO TUESDAY MORNING.
SURFACE WARM FRONT/STRONG WARM AIR ADVECTS INTO THE AREA TUESDAY
NIGHT INTO WEDNESDAY. THE NAM IS MORE AGGRESSIVE ADVECTING THE
WARMER AIR INTO THE REGION...WITH THE NAM 925MB TEMPERATURES
WARMING TO PLUS 2 TO 3 DEGREES CELSIUS OVER THE SOUTHERN FORECAST
AREA. THE 16.12Z GFS MUCH COOLER WITH 925MB TEMPERATURES MINUS 3
TO MINUS 4 DEGREES CELSIUS OVER THE SOUTHERN FORECAST AREA. DUE TO
THE FRESH SNOW COVER AND MODEL DIFFERENCES ON POSITION OF SURFACE
WARM FRONT/WARMER AIR ALOFT CONFIDENCE IN TEMPERATURES IS LOW.
KEPT A BLEND OF TEMPERATURES AT THIS TIME FRAME.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 341 PM CST MON DEC 16 2013
MAIN FOCUS IS WEDNESDAY NIGHT INTO THURSDAY WITH WEAK SURFACE
LOW/SHORTWAVE TROUGH EJECTING OUT INTO THE CENTRAL PLAINS STATES.
THE LATEST 16.12Z GFS/NAM ARE INDICATING NEAR SURFACE BOUNDARY LAYER
SATURATING UNDER STRONG INVERSION WEDNESDAY NIGHT INTO THURSDAY
MORNING. THE 16.12Z GFS/NAM BUFKIT SOUNDINGS OVER THE SOUTHERN
FORECAST AREA SHOW WEAK VERTICAL MOTION AT THE TOP OF THE INVERSION
LAYER AND NO ICE INTRODUCTION BELOW THE INVERSION. DEPENDING ON
TEMPERATURES AT SURFACE...EXPECT DRIZZLE OR FREEZING DRIZZLE TO
DEVELOP OVER THE SOUTHERN FORECAST AREA. PER BUFKIT SOUNDINGS AFTER
18Z THURSDAY...DEEPER SATURATION OCCURS AND ALLOWS RAIN TO SPREAD
ACROSS THE SOUTHERN FORECAST AREA. DUE TO THE FROZEN GROUND AND
POSSIBLY TEMPERATURES NEAR OR A DEGREE OR TWO BELOW
FREEZING...FREEZING RAIN IS A POSSIBLE OVER THE SOUTHERN HALF OF THE
FORECAST AREA.
THURSDAY NIGHT INTO MONDAY...MAIN FORECAST CONCERNS ARE
PRECIPITATION CHANCES THROUGH PERIOD. THE 16.00Z GFS/ECMWF/GEM ARE
IN GOOD AGREEMENT IN DIGGING UPPER LEVEL TROUGH AND DEVELOPING
NORTHWEST FLOW ALOFT OVER THE UPPER GREAT LAKES REGION THIS WEEKEND
AND INTO EARLY NEXT WEEK. THE BIGGEST DIFFERENCES IN THE MODELS ARE
TIMING OF THE UPPER LEVEL/SURFACE LOW EJECTING OUT INTO THE CENTRAL
PLAINS/GREAT LAKES REGION THIS WEEKEND AND SHORTWAVE TROUGH EMBEDDED
IN THE NORTHWEST FLOW ALOFT EARLY NEXT WEEK. THE 16.00Z GFS/ECMWF
ARE IN DECENT AGREEMENT IN TRACKING FIRST WEAK IMPULSE INTO NORTHERN
ILLINOIS AND SOUTHERN LAKE MICHIGAN THURSDAY NIGHT AND PLACING
ASSOCIATED DEFORMATION BAND OF PRECIPITATION ACROSS NORTHERN
WISCONSIN. AT THIS TIME...NOT CONFIDENT ON HIGH CHANCES OF
PRECIPITATION THURSDAY NIGHT ACROSS FORECAST AREA...AS THE GFS/ECMWF
DPROG/DT TRENDING THE MAIN LIFT AND FORCING NORTH AND SOUTH OF
FORECAST AREA THE LAST COUPLE OF RUNS. THE MODELS ARE IN AGREEMENT
TRACKING THIS WEEKEND UPPER LEVEL/SURFACE LOW SOUTH OF FORECAST AREA
AND ALLOWS UPPER LEVEL TROUGH TO DIG OVER THE GREAT LAKES REGION AND
DEVELOP NORTHWEST FLOW OVER FORECAST AREA. THIS WILL CONTINUE TO
ADVECT IN UNSEASONABLY COLD ARCTIC AIRMASS INTO THE FORECAST AREA
LATE THIS WEEKEND INTO EARLY NEXT WEEK. THE 16.00Z MODELS SHOW
DIFFERENCES IN TIMING OF SHORTWAVE TROUGH EMBEDDED IN NORTHWEST FLOW
TO MOVE ACROSS THE GREAT LAKES REGION EARLY NEXT WEEK. WITH MODELS
INDICATING ENOUGH LIFT AND MOISTURE ASSOCIATED WITH SHORTWAVE
TROUGH...SMALL PRECIPITATION CHANCES ARE WARRANTED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1140 PM CST MON DEC 16 2013
THE NEXT BAND OF LIGHT SNOW WAS STARTING TO TAKE SHAPE OVER
CENTRAL AND NORTHERN MINNESOTA. THE SHORT WAVE TROUGH WITH THIS
BAND OF SNOW LOOKS TO TRACK FARTHER TO THE NORTH THAN PREVIOUSLY
EXPECTED. THIS HAS RESULTED IN A NORTHWARD SHIFT OF WHERE THE SNOW
SHOULD FALL AS WELL AND IT NOW COULD BE QUITE POSSIBLE THAT
NEITHER TAF SITE COULD SEE ANY SNOW. KLSE LOOKS TO HAVE A SLIGHTLY
BETTER CHANCE OF BEING BRUSHED BY THE SOUTHERN EXTENT OF THE SNOW
BAND AND HAVE SHOWN A SHORT PERIOD OF PREVAILING MVFR WITH THE
POSSIBILITY OF IFR...BUT CONFIDENCE IS NOT HIGH IN THIS AT ALL.
FOR KRST...HAVE GONE TO PREVAILING VFR OVERNIGHT WITH A
POSSIBILITY OF MVFR IF THE SNOW BAND CAN REACH THE AIRPORT. THE
SNOW CHANCES WILL END BEFORE SUNRISE AS A COLD FRONT GOES
THROUGH. THE 17.00Z NAM AND 18.03Z RAP NOW BOTH SHOW THE INVERSION
HOLDING TOUGH BEHIND THE FRONT UNTIL MID MORNING. ONCE THE
INVERSION MIXES OUT...GOOD LOW LEVEL LAPSE RATES DEVELOP THAT WILL
ALLOW FOR SUSTAINED NORTHWEST WINDS BETWEEN 15 AND 20 KNOTS WITH
GUSTS OF BETWEEN 25 AND 30 KT. THIS WILL LIKELY PRODUCE A LOT OF
DRIFTING SNOW AND POSSIBLY A LITTLE BIT OF BLOWING SNOW AT KRST.
THERE SHOULD ALSO BE ENOUGH RESIDUAL LOW LEVEL MOISTURE TO ALLOW
A MVFR CEILING TO DEVELOP ON TOP OF THE INSTABILITY LAYER. THE
INVERSION WILL REDEVELOP EARLY TUESDAY EVENING ALLOWING THE WINDS
TO SETTLE DOWN TO AROUND 10 KNOTS ENDING THE BLOWING SNOW AND MVFR
CEILINGS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM...DTJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS ALBANY NY
1040 AM EST TUE DEC 17 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM PASSING SOUTH OF THE REGION WILL BRING A
WIDESPREAD LIGHT TO MODERATE SNOWFALL TO THE AREA TODAY. THE SNOW
WILL SPREAD NORTHWARD ACROSS THE AREA DURING THIS MORNING AND IS
EXPECTED TO TAPER OFF THIS EVENING. SCATTERED SNOW SHOWERS ARE
THEN EXPECTED TONIGHT AND WEDNESDAY...ESPECIALLY ACROSS THE HIGHER
TERRAIN. A GRADUAL WARMING TREND IS THEN EXPECTED FOR THE END OF
THE WORKWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1040 AM EST...UPDATED THE WINTER WX ADVISORY TO INCLUDE THE
CAPITAL REGION...MOHAWK RIVER VALLEY...SCHOHARIE VALLEY...AND
HELDERBERGS. SNOWFALL POTENTIAL OF 2 TO 6 INCHES HERE BASED ON THE
LATEST RADAR...12Z NAM...AND RUC TRENDS. EXPECTING SNOW TO LIQUID
RATIOS OF 15-20:1 TO ACCOUNT FOR TOTALS TO GET INTO THE ADVISORY
RANGE. THE KENX AND KBGM RADARS INDICATING SOME BANDLETS OR MINI
BANDS WITH SNOW RATES APPROACHING A HALF AN INCH TO AN INCH AND
HOUR. THE ADVISORY WILL ALSO GO TO 00Z/7 PM EST.
SNOW HAS BEEN RAPIDLY EXPANDING NORTHWARD ACROSS THE REGION WITH
RECENT RADAR TRENDS INDICATING MODERATE BANDS MOVING NORTHWARD. A
FEW BREAKS ACROSS THE MID HUDSON VALLEY HAVE OCCURRED BUT SHOULD
FILL BACK IN AS SURFACE LOW DEVELOPS JUST OFF THE NJ COAST.
850-700HPA 2D FGEN PER THE RUC13/HRRR INDICATES A BAND OF MODERATE
SNOW SHOULD DEVELOP EITHER ALONG OR SOUTH OF I90 LATE THIS
AFTERNOON AS WE WILL LEAVE THE CURRENT HEADLINES IN PLACE. WE ARE
EXPECTING THE SNOW TO LIQUID RATIOS TO DROP CLOSER TO 15:1 IN THE
STRONG WARM ADVECTION REGIME...AND WITH THE SECONDARY LOW PRESSURE
DEVELOPMENT OCCURRING NEAR SE NJ AT THIS TIME.
TEMPS TODAY WILL STRUGGLE TO CLIMB INTO AND THROUGH THE TEENS TO
LOWER 20S IN VALLEY AREAS...AND LOWER TO MID TEENS ACROSS HIGHER
ELEVATIONS...WITH MAX TEMPS LIKELY NOT OCCURRING UNTIL BETWEEN 5-7
PM. GIVEN THAT THE CLOUDS WILL BE RATHER LOW...AND THAT MUCH OF
THE PRECIP WILL BE FALLING FROM A LOWER CLOUD DECK INITIALLY THEN
WHAT OCCURRED ON SATURDAY...THE POTENTIAL AND DEPTH OF WET BULB
COOLING WILL BE LESS THAN WHAT OCCURRED THIS PAST SAT. SO...WE
HAVE SIDED WITH THE COOLER SIDE OF A MAV/MET MOS BLEND...BUT DID
NOT STRAY TOO MUCH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
TONIGHT...ANY STEADIER SNOW SHOULD TAPER OFF ACROSS SE VT EARLY.
OTHERWISE...EXPECT SCATTERED SNOW SHOWERS TO OCCUR OVERNIGHT AS
THE MID/UPPER LEVEL TROPOSPHERIC TROUGH AND COLD POOL PASS
THROUGH...WITH 500 MB TEMPS DIPPING INTO THE -35C TO -40C RANGE.
925-700 LAPSE RATES STEEPEN...AND SHOULD ENOUGH MOISTURE BE
PRESENT WITHIN THIS LAYER...COULD LEAD TO SOME EMBEDDED HEAVIER SNOW
SHOWERS AND/OR SQUALLS...LEAVING ADDITIONAL COATINGS...TO PERHAPS
UP TO AN INCH OF SNOWFALL OVERNIGHT. TEMPS SHOULD FALL INTO THE
TEENS IN MOST AREAS.
WED-WED NT...THE AFOREMENTIONED MID LEVEL TROUGH/COLD POOL MOVES E
OF THE REGION IN THE AFTERNOON. HOWEVER...A FAIRLY WELL ALIGNED
WESTERLY FLOW MAY ALLOW FOR LAKE EFFECT SNOWBANDS TO DEVELOP
ACROSS NORTHERN HERKIMER CO IN THE AFTERNOON...AND MAY EXTEND WELL
INTO HAMILTON CO OR EVEN NW WARREN CO FOR A BRIEF TIME LATE IN THE
AFTERNOON INTO EARLY WED NT...AS SUGGESTED PER THE CSTAR FUNDED
INLAND LAKE EXTENT PROGRAM. THIS COULD LEAD TO AT LEAST 1-3 INCHES
OF SNOWFALL...WITH SOME POTENTIAL FOR GREATER AMTS...PERHAPS INTO
THE ADVISORY RANGE. WILL ADDRESS THIS POTENTIAL IN THE HWOALY.
ELSEWHERE...SCATTERED SNOW SHOWERS AND FLURRIES WILL BE POSSIBLE
ACROSS HIGHER ELEVATIONS...WHERE ADDITIONAL MINOR ACCUMS COULD
OCCUR...WITH SOME SNOW SHOWERS/FLURRIES OCCASIONALLY MIGRATING
INTO VALLEY AREAS...ESP NEAR AND N OF THE MOHAWK RIVER. FOR
TEMPS...EXPECT SLIGHTLY MILDER MAX TEMPS WED...REACHING THE 20S TO
LOWER 30S IN VALLEYS...WITH TEENS TO MID 20S ACROSS HIGHER
ELEVATIONS...AND OVERNIGHT MINS WED NT/THU AM FALLING MAINLY INTO
THE TEENS...WITH SOME SINGLE DIGITS POSSIBLE ACROSS NORTHERN AREAS
AND HIGHER ELEVATIONS ACROSS WESTERN NEW ENGLAND.
THU-THU NT...A SOUTHWEST LOW LEVEL FLOW WILL DEVELOP DURING THIS
TIME...ALLOWING FOR GRADUAL MODERATION IN TEMPS. SOME LINGERING
LAKE EFFECT SNOW MAY OCCUR THU ACROSS EXTREME NORTHERN
HERKIMER/HAMILTON COS...BEFORE THE INVERSION LEVEL FALLS.
THEN...SOME WARM ADVECTION PRECIP COULD DEVELOP ACROSS THE WESTERN
DACKS LATE THU NT...IN THE FORM OF LIGHT SNOW...OR EVEN A LIGHT
WINTRY MIX. THU MAX TEMPS SHOULD REACH THE LOWER/MID 30S IN
VALLEYS...AND 20S ACROSS HIGHER ELEVATIONS...WITH OVERNIGHT MINS
THU NT/FRI AM ONLY FALLING INTO THE 20S IN MOST AREAS...WITH TEMPS
POSSIBLY RISING IN SOME AREAS LATE AT NIGHT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
INCREASING AGREEMENT IN THE MODEL AND ENSEMBLE GUIDANCE THROUGH THE
PERIOD. ONE UPPER IMPULSE AND ASSOCIATED FORCING SUPPORTS
PRECIPITATION FRIDAY AND FRIDAY NIGHT. THEN ANOTHER UPPER IMPULSE
AND ASSOCIATED FORCING AFFECTS OUR REGION SATURDAY NIGHT THROUGH
SUNDAY NIGHT. THE TIMING OF THESE SYSTEMS WILL LIKELY GET ADJUSTED
WITH TIME AS THEY ARE WITHIN QUICK WEST SOUTHWEST UPPER CONFLUENT
STEERING FLOW. ALSO...WORDING RAIN AND SNOW THROUGH THE PERIOD SINCE
THERE IS SUCH HIGH UNCERTAINTY IN THE POTENTIAL AREAS OF SLEET
AND/OR FREEZING RAIN.
THE PRECIPITATION TYPES AND THE POSITION OF A POTENTIALLY BROAD
PRECIPITATION TRANSITION ZONE ARE STILL IN QUESTION. HOWEVER...
THERE IS MORE AGREEMENT FOR ANY MIXED PRECIPITATION EARLY FRIDAY
MORNING TO CHANGE TO MAINLY LIQUID PRECIPITATION OVER CENTRAL AND
SOUTHERN AREAS BEFORE COVERAGE OF PRECIPITATION DECREASES FRIDAY
NIGHT. MIXED PRECIPITATION COULD REMAIN MIXED OVER NORTHERN AREAS.
HIGHS FRIDAY IN THE LOWER TO MID 40S IN MANY AREAS WITH MID TO UPPER
30S IN THE HIGHER ELEVATIONS.
LOW LEVEL FORCING WEAKENS FRIDAY NIGHT AND SATURDAY WITH WEAK LOW
LEVEL RIDGING OVER THE REGION. LINGERING MOISTURE AND PROXIMITY TO
THE LOW LEVEL THERMAL GRADIENT AND WIND CONVERGENCE PROXIMATE TO THE
LOW LEVEL BOUNDARY COULD SUPPORT SCATTERED SHOWERS...WITH SOME
FLURRIES OR SNOW SHOWERS. THE BRIEF LOW LEVEL RIDGING COULD ALLOW
TEMPERATURES TO FALL TO NEAR FREEZING IN MANY AREAS FRIDAY NIGHT AND
MID TO UPPER 20S IN THE HIGHER ELEVATIONS... AGAIN SUPPORTING
SCATTERED SHOWERS AND SNOW SHOWERS.
CURRENT GUIDANCE SUGGESTS THE NEXT SYSTEM ARRIVES THROUGH THE DAY
SATURDAY AN CONTINUES SATURDAY NIGHT THROUGH SUNDAY...EXITING SUNDAY
NIGHT. THE WARM ADVECTION AND FORCING LOOK STRONGER WITH THIS
SYSTEM...DRIVING THE WARM AIR FURTHER NORTH...SUPPORTING A
PRECIPITATION TRANSITION TO RAIN IN MOST AREAS. QUITE A STRONG
SOUTHWEST TO WEST SOUTHWEST BOUNDARY LAYER JET TRACKS THROUGH THE
REGION AND THE BOUNDARY LAYER THERMAL GRADIENT IS QUITE TIGHT AS IT
TRACKS EAST AND SOUTH SUNDAY AND SUNDAY NIGHT. SO...WILL HAVE TO
KEEP AN EYE ON WINDS AND POTENTIAL FOR LOCALLY HEAVY RAIN ON THE
MELTING SNOW PACK. HIGHS SATURDAY IN THE LOWER TO MID 40S...LOWER
TO MID 30S HIGHER ELEVATIONS. HIGHS SUNDAY IN THE UPPER 40S TO LOWER
50S...WITH UPPER 30S TO LOWER 40S IN HIGHER ELEVATIONS.
STRONG COLD ADVECTION SPREADS ACROSS THE REGION BY MONDAY MORNING
AND CONTINUES THROUGH THE DAY. SOME LAKE EFFECT SNOW BANDS SHOULD
FORM BUT INLAND EXTENT IS IN QUESTION. HIGHS MONDAY IN THE 20S TO
LOWER 30S.
THERE COULD STILL BE A LOT OF CHANGES TO HOW THESE SYSTEMS DEVELOP
AND IMPACT THE REGION. THERE ARE INDICATIONS OF A POTENTIAL BROAD
MIXED PRECIPITATION TRANSITION ZONE...BUT THE POSITION AND AREAL
EXTENT OF THE PRECIPITATION TRANSITION ZONE KEEPS CHANGING IN
SUCCESSIVE SETS OF GUIDANCE. THERE IS STILL A CHANCE THAT THE
CURRENT INDICATIONS OF MORE RAIN AND LESS WINTERY PRECIPITATION OVER
MUCH OF OUR REGION COULD CHANGE BACK TO COLDER AND MORE MIXED
PRECIPITATION DEPENDING ON HOW THE SYSTEMS DEVELOP IN THE NEXT 3+
DAYS. HOWEVER...THE INCREASING CONSENSUS FROM GUIDANCE OF MORE
LIQUID AND LESS MIXED PRECIPITATION SEEMS THE MOST LIKELY SCENARIO
AT THIS TIME.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
A LOW PRESSURE SYSTEM WILL BRING A WIDESPREAD LIGHT TO MODERATE
SNOWFALL TO THE AREA TODAY. THE SNOW WILL SPREAD NORTHWARD ACROSS
THE AREA DURING THE MORNING AND IS EXPECTED TO TAPER OFF TOWARD THIS
EVENING.
SNOW IS BEGINNING AT KPOU AND WILL SPREAD NORTHWARD TO KALB AND KPSF
BY 13Z-14Z AND BY KGFL BY 14Z. INITIALLY MVFR CONDITIONS ARE
EXPECTED WITH IFR DEVELOPING AS THE SNOW BECOMES STEADIER AS THE
MORNING PROGRESSES. AROUND 5 HOURS OF IFR SNOWS ARE EXPECTED WITH AN
IMPROVE BACK TO MVFR MID TO LATE AFTERNOON. KEEPING VCSH THROUGH
ABOUT 05Z AT ALL TAF SITES WITH LINGERING MOISTURE. AFTER
05Z-06Z...VFR CEILINGS AND VISIBILITIES SHOULD PREVAIL AT ALL TAF
SITES.
WINDS WILL BE NEARLY CALM THROUGH THE MORNING HOURS WITH A LIGHT
SOUTHEASTERLY FLOW DEVELOPING LATER IN THE MORNING AND BECOMING
VARIABLE AGAIN BY LATE AFTERNOON AND EVENING.
OUTLOOK...
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. SCATTERED SHRA...SHSN.
SATURDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
&&
.HYDROLOGY...
A CLIPPER TYPE SYSTEM WILL AFFECT THE REGION TODAY INTO THIS
EVENING. THE PRECIPITATION IS EXPECTED TO BE ALL SNOW WITH THIS
SYSTEM. TOTAL LIQUID EQUIVALENT WITH THIS SYSTEM IS EXPECTED TO
RANGE FROM ONE TO THREE TENTHS OF AN INCH WITH THE HIGHEST AMOUNTS
OVER THE ERN CATSKILLS...W-CNTRL MOHAWK VALLEY...AND WRN NEW
ENGLAND. THIS SYSTEM WILL REDEVELOP SOUTH OF LONG ISLAND...AND
QUICKLY MOVE NORTHEAST OF CAPE COD TOMORROW NIGHT.
SOME LAKE EFFECT SNOW IS POSSIBLE WED-THU WITH LIGHT SNOW
AMOUNTS...AND LIQUID EQUIVALENTS GENERALLY LESS THAN A TENTH OF AN
INCH FOR THE WRN DACKS REGION...AND NRN TIER OF THE HSA.
FOR THE MID WEEK...TEMPS WILL CONTINUE TO BE BELOW NORMAL AND ICE
WILL CONTINUE TO FORM AND THICKEN ON AREA RIVERS...STREAMS AND
PARTICULARLY LAKES.
A MODERATING TREND IN TEMPS IS LIKELY THU INTO FRI...WITH A
FRONTAL BOUNDARY BRINGING SOME SHOWERS TO CLOSE THE WORK WEEK.
SOME SNOW MELT IS LIKELY THIS WEEKEND. ALSO...A STORM SYSTEM
MOVING ALONG A FRONTAL BOUNDARY NEAR THE HSA MAY BRING SIGNIFICANT
PCPN TO THE FORECAST AREA SAT NIGHT INTO SUNDAY WITH EVEN MILDER
TEMPS. THIS WILL CONTINUE TO BE MONITORED FOR THE UPCOMING
WEEKEND.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR CTZ001-
013.
NY...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
NYZ038>040-047>054-058>061-063>066-082.
MA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MAZ001-
025.
VT...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
VTZ013>015.
&&
$$
SYNOPSIS...KL/WASULA
NEAR TERM...KL/BGM/WASULA
SHORT TERM...KL
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...KL/WASULA
AREA FORECAST DISCUSSION
NWS TAUNTON MA
702 AM EST TUE DEC 17 2013
.SYNOPSIS...
A FAST MOVING LOW PRESSURE SYSTEM WILL BRING ACCUMULATING SNOW TO
THE REGION TODAY. DRY BUT CHILLY AND BLUSTERY WEATHER FOLLOWS WED
BEHIND THE DEPARTING LOW. SOMEWHAT MILDER WEATHER ARRIVES THU AND
FRI WITH THE POTENTIAL FOR UNSETTLED WEATHER THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM UPDATE...BIG STORY AT THIS TIME IS THE COLD TEMPERATURES.
ASIDE FROM THE SOUTH COAST AND THE LARGER CITIES...TEMPERATURES
ARE IN THE SINGLE DIGITS BOTH ABOVE AND BELOW ZERO. HOWEVER...THE
FOCUS WILL TURN QUICKLY TO THE APPROACHING SNOW. THE LEADING EDGE
OF THE SNOW HAS WORKED ITS WAY INTO SOUTHWESTERN CONNECTICUT.
WHILE DEWPOINTS ARE VERY LOW THIS MORNING...THEY HAVE BEEN RISING
QUICKLY AS THE SNOW MOVES IN. STILL ANTICIPATING SNOW TO ARRIVE IN
THE HARTFORD METRO AREA ABOUT 8 AM...WORCESTER AND PROVIDENCE
AROUND 10 AM AND BOSTON METRO AROUND 11 AM.
MADE SOME EDITS TO THE TEMPERATURES AND DEWPOINTS TO BRING THEM
MORE IN LINE WITH CURRENT TRENDS. HIGH RESOLUTION NEAR TERM MODELS
ARE STRUGGLING WITH THE COLD BUT THE HRRR FINALLY CAUGHT UP TO THE
TEMPERATURES...SO USED THAT TO ADJUST THE TEMPS. OTHERWISE...THE
FORECAST IS ON TRACK.
PREVIOUS DISCUSSION...
AS FOR THE REST OF TODAY...VERY TRICKY FORECAST FOR SNOW
ACCUMULATIONS DESPITE VERY COLD TEMPERATURES TO START. 17/00Z GFS
APPEARS TO BE A SLOWER AND STRONGER OUTLIER SOLUTION. WILL STICK
WITH THE CONSENSUS TIMING OF THE OTHER GUIDANCE. THIS WOULD TAKE A
FAST-MOVING LOW PRESSURE FROM THE MID ATLANTIC COAST THIS
MORNING...ACROSS CAPE COD AND THE ISLANDS THIS EVENING.
THIS TRACK WILL COMPLICATE SNOW ACCUMULATIONS ACROSS SOUTHEAST MA
AND SOUTHERN RI AS ONSHORE FLOW OVER 45F-50F WATER WILL RESULT IN
AT LEAST SOME WARMING IN THE LOW LEVELS. UNLIKE THE STORM THIS
PAST WEEKEND...THINKING MIXING ZONE WILL STAY CLOSER TO THE COAST
AS THIS LOW PRESSURE SHOULD REMAIN WEAKER.
AT THIS TIME WATCHING LIGHT SNOW BREAK OUT ACROSS CENTRAL AND
NORTHEAST PA. THIS COULD PUT SOME SNOW INTO SOUTHERN NEW ENGLAND
FOR THE MORNING COMMUTE...BUT VISIBILITY SHOULD NOT BE BAD. THE
HARTFORD-SPRINGFIELD METRO AREA WOULD BE MOST AFFECTED. THE
AFTERNOON/EVENING COMMUTE WILL BE MORE PROBLEMATIC WITH POOR
VISIBILITY AND SLIPPERY TRAVEL. PLEASE KEEP THIS IN MIND WHEN
PLANNING YOUR DAY.
THERE IS SOME POTENTIAL FOR CONVECTIVE BANDING...MAINLY ACROSS
NORTH CENTRAL AND NORTHEAST MA INTO SOUTHERN NH. ENHANCEMENT IN
THIS AREA IS MORE LIKELY AS WELL WITH ONSHORE FLOW PRODUCING AN
OCEAN EFFECT CONTRIBUTION. THERE COULD BE OTHER AREAS OF
CONVECTIVE ENHANCEMENT...BUT DO NOT HAVE AS HIGH A CONFIDENCE AS
THE MERRIMACK VALLEY. THINKING MOST AREAS WILL SEE AROUND 4 INCHES
OF SNOWFALL ACROSS THE INTERIOR WITH LOCALLY HIGHER AMOUNTS WHEN
ALL IS DONE.
DECIDED THE END TIMING OF THE WINTER WEATHER ADVISORIES WAS TOO
CLOSE FOR COMFORT. EXTENDED THE ADVISORY FOR THE WESTERN HALF OF
SOUTHERN NEW ENGLAND AND SOUTHEAST MA AND RI TO COVER MORE OF THE
EVENING COMMUTE. ALSO EXTENDED THE ADVISORY FOR SOUTHERN NH AND
NORTHEAST MA...WITH THE THOUGHT OF A LONGER PERIOD OF SNOW IN THE
MERRIMACK VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
PRECIPITATION WILL TAPER OFF FROM SOUTHWEST TO NORTHEAST LATE THIS
AFTERNOON INTO THIS EVENING. THE SKY CLEARING MAY TAKE A WHILE
LONGER AS THIS LOW PRESSURE DEVELOPS IN THE GULF OF MAINE AND
SENDS MORE CLOUDS BACK IN OUR DIRECTION. THINKING ONSHORE WINDS
WILL ALSO GENERATE SOME OCEAN-EFFECT SNOW BANDS...SO KEPT A CHANCE
OF SNOW ACROSS THE EASTERN HALF OF SOUTHERN NEW ENGLAND THROUGH
LATE TONIGHT.
BRISK WEST TO NORTHWEST WINDS WEDNESDAY SHOULD HELP PROVIDE
CLEARING WEDNESDAY...ALONG WITH DRIER WEATHER FOR THE AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HIGHLIGHTS...
* MILDER TEMPERATURES THU AND FRI
* UNSETTLED WEATHER OVER THE WEEKEND
MODELS ARE STRUGGLING WITH THE EVENTUAL EVOLUTION OF THE SPLIT FLOW
REGIME OVER THE EAST COAST. HAVE OPTED TO GO WITH A MORE WPC
SOLUTION...WHICH INCORPORATES ALL OF THE ENSEMBLE MEANS.
WEDNESDAY NIGHT THROUGH FRIDAY...SOUTHWESTERLY SURFACE WINDS WILL
DRAW WARMER AIR INTO THE REGION...RESULTING IN DAYTIME TEMPERATURES
WARMING THROUGH THIS PERIOD. WILL START TO SEE TEMPERATURES CLOSER
TO AVERAGE FOR MID DECEMBER INSTEAD OF THE 5-10 DEGREES BELOW NORMAL
WE HAVE HAD LATELY. THERE ARE DIFFERENCES IN HOW THE MODELS HANDLE
LOW PRESSURE MOVING THROUGH THE GREAT LAKES AND THE COLD FRONT
EXTENDING SOUTHWESTWARD FROM IT WHICH MAY AFFECT THE FORECAST FOR
THIS TIME FRAME. RIGHT NOW...AM FORECASTING THE FRONT TO MOVE INTO
SOUTHERN NEW ENGLAND EARLY SATURDAY.
SATURDAY THROUGH MONDAY...LOW PRESSURE MOVING INTO THE MARITIMES
WILL PULL A COLD FRONT THROUGH SOUTHERN NEW ENGLAND EARLY SATURDAY.
THIS FRONT THEN APPEARS TO STALL WHILE WAVES OF LOW PRESSURE MOVE
ALONG IT. THIS WILL RESULT IN SOME VERY UNSETTLED WEATHER OVER THE
WEEKEND. IT LOOKS LIKELY THAT SOME FORM OF PRECIPITATION WILL OCCUR
OVER MUCH OF THE REGION. UNFORTUNATELY TEMPERATURE PROFILES ARE
SUCH THAT SMALL SHIFTS WILL MAKE A BIG DIFFERENCE IN PRECIPITATION
TYPE. AT THIS TIME...IT LOOKS LIKE MUCH OF SATURDAY WILL BE
WARM...WITH TEMPERATURES ABOVE FREEZING THROUGH THE PROFILE DURING
THE DAY. THIS WOULD LEAD TO RAIN DURING THE DAY. AT NIGHT...A
WINTRY MIX IS POSSIBLE. THIS IS FURTHER COMPLICATED BY STRONG HIGH
PRESSURE IN SOUTHERN CANADA...WHICH COULD RESULT IN SOME COLD AIR
DRAINAGE. IN THIS CASE...TEMPERATURES AT THE SURFACE COULD BE BELOW
FREEZING WHILE THE THERMAL PROFILE REMAINS FAVORABLE FOR
RAIN...LEADING TO FREEZING RAIN. THERE IS A LOT OF UNCERTAINTY
RIGHT NOW...PARTICULARLY FOR THE WEEKEND. BELIEVE THE FRONT WILL
FINALLY MOVE OFFSHORE FOR MONDAY...ALLOWING HIGH PRESSURE TO BUILD
INTO THE REGION.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH WEDNESDAY/...HIGH CONFIDENCE IN TRENDS. LOWER
CONFIDENCE IN TIMING OF IFR CONDITIONS IN SNOW.
TODAY...CONDITIONS LOWERING TO MVFR-IFR FROM SW TO NE THIS MORNING
AS SNOW OVERSPREADS THE REGION. AREAS OF IFR THIS AFTERNOON WITH
LOCALLY HEAVY SNOW AT TIMES. SNOW ACCUM 3-5 INCHES POSSIBLE ALL
TERMINALS...LESS KFMH/KHYA/KACK WHERE SNOW WILL MIX WITH OR CHANGE
TO RAIN LATER TODAY.
TONIGHT...SNOW WILL LIKELY LINGER INTO THIS EVENING ACROSS
EASTERN MA WITH SOME SNOW SHOWERS POSSIBLE ELSEWHERE.
WEDNESDAY...IMPROVEMENT TO VFR FROM WEST TO EAST...MUCH MORE
RAPIDLY ACROSS THE INTERIOR THAN TOWARD THE EAST COAST OF MA.
KBOS TAF...HIGH CONFIDENCE IN DETERIORATING CONDITIONS BY MIDDAY
AS SNOW MOVES IN. EXACT TIMING MAY BE OFF A FEW HOURS.
KBDL TAF...HIGH CONFIDENCE IN DETERIORATING CONDITIONS THIS
MORNING AS SNOW MOVES IN. EXACT TIMING MAY BE OFF A FEW HOURS.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
WEDNESDAY NIGHT THROUGH THURSDAY...HIGH CONFIDENCE. VFR.
FRIDAY...MODERATE CONFIDENCE. MAINLY VFR. MVFR/IFR CONDITIONS
DEVELOP LATE FRIDAY NIGHT IN FOG AND LOW CLOUDS.
SATURDAY...LOW CONFIDENCE. MVFR/IFR CONDITIONS LIKELY IN POSSIBLY A
WINTRY MIX OF PRECIPITATION.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH WEDNESDAY/...HIGH CONFIDENCE.
ANOTHER ROUND OF EASTERLY SCA WIND GUSTS TO 25-30 KT LIKELY THIS
AFTERNOON INTO THIS EVENING...ESPECIALLY OUTER WATERS ASSOCIATED
WITH A COASTAL STORM. REDUCED VSBYS THIS AFTERNOON AND EVENING IN
RAIN AND SNOW. WILL REEVALUATE NEED TO ISSUE NEW SMALL CRAFT
ADVISORIES SOON.
WEDNESDAY...HIGH CONFIDENCE. WEST TO NORTHWEST SCA WIND GUSTS OF 25
TO 30 KTS EXPECTED WITH COLD ADVECTION OVER THE RELATIVELY MILD
OCEAN.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
WEDNESDAY NIGHT AND THURSDAY...MODERATE CONFIDENCE. SOUTHWESTERLY
WINDS AND SEAS DIMINISH GRADUALLY. SMALL CRAFT ADVISORIES WILL
LIKELY BE NEEDED FOR MUCH OF THIS TIME AS GUSTS ABOVE 25 KTS ARE
LIKELY.
FRIDAY...MODERATE CONFIDENCE. WINDS AND SEAS REMAIN AT OR JUST
UNDER SMALL CRAFT CRITERIA.
SATURDAY...LOW CONFIDENCE. HIGHLY UNCERTAIN ON WIND SPEED AND
DIRECTION.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
CTZ002>004.
MA...WINTER WEATHER ADVISORY UNTIL 11 PM EST THIS EVENING FOR
MAZ004>007-012-014-026.
WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR MAZ013-
015>021.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MAZ002-
003-008>011.
NH...WINTER WEATHER ADVISORY UNTIL 11 PM EST THIS EVENING FOR
NHZ011-012-015.
RI...WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR
RIZ001>007.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 9 PM EST THIS EVENING
FOR ANZ231>235-237.
SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 7 PM EST
WEDNESDAY FOR ANZ250.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 7 PM EST WEDNESDAY FOR
ANZ254>256.
&&
$$
SYNOPSIS...BELK/RLG
NEAR TERM...BELK/RLG
SHORT TERM...BELK
LONG TERM...RLG
AVIATION...BELK/RLG
MARINE...BELK/RLG
AREA FORECAST DISCUSSION
NWS ALBANY NY
638 AM EST TUE DEC 17 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM PASSING SOUTH OF THE REGION WILL BRING A
WIDESPREAD LIGHT TO MODERATE SNOWFALL TO THE AREA TODAY. THE SNOW
WILL SPREAD NORTHWARD ACROSS THE AREA DURING THIS MORNING AND IS
EXPECTED TO TAPER OFF THIS EVENING. SCATTERED SNOW SHOWERS ARE
THEN EXPECTED TONIGHT AND WEDNESDAY...ESPECIALLY ACROSS THE HIGHER
TERRAIN. A GRADUAL WARMING TREND IS THEN EXPECTED FOR THE END OF
THE WORKWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 615 AM EST...BITTER COLD REIGNS ACROSS THE REGION...WITH
WIDESPREAD TEMPS OF -10F TO -20F ACROSS THE NORTH COUNTRY...AND -5F
TO +5F ELSEWHERE.
CLOUDS ARE RAPIDLY INCREASING ACROSS CENTRAL AND SOUTHERN
AREAS...WITH A RATHER LOW DECK...WITH CIGS GENERALLY BETWEEN
3500-5000 FT AGL. LIGHT SNOW IS CURRENTLY DEVELOPING THE SE
CATSKILLS/MID HUDSON VALLEY REGION...AND WILL SPREAD ACROSS THE
CAPITAL REGION...SCHOHARIE VALLEY...NW CT AND BERKSHIRES BETWEEN
ROUGHLY 7 AM-10 AM...AND INTO THE MOHAWK VALLEY...THE LAKE
GEORGE/SARATOGA REGION AND SOUTHERN VT BETWEEN 10 AM AND NOON.
ONCE THE SNOW STARTS...WE EXPECT PERIODS OF LIGHT TO MODERATE SNOW
TO CONTINUE THROUGH EARLY THIS EVENING...WITH TOTAL ACCUMS
GENERALLY 2-4 INCHES...EXCEPT FOR 3-6 INCHES ACROSS PORTIONS OF
THE MID HUDSON VALLEY...NW CT...BERKSHIRES...SOUTHERN VT AND SE
CATSKILLS WHERE SOME OROGRAPHIC ENHANCEMENT IS LIKELY...AND 1-3
INCHES ACROSS THE SOUTHERN ADIRONDACKS.
IT APPEARS THAT THERE WILL BE 2 MAIN BURSTS OF SNOW THROUGH
TODAY...THE FIRST ONE BEING DRIVEN MAINLY BY LOW/MID LEVEL WARM
ADVECTION...WHICH WILL BE MAINLY THIS MORNING...THEN PERHAPS THE
BEST BURST OF SNOW LATE THIS AFTERNOON INTO EARLY THIS
EVENING...DUE TO ENHANCED 850-700 FRONTOGENESIS TO THE N/NW OF AN
EMBEDDED SHORTWAVE TRANSLATING JUST S/E OF THE
REGION...INTERACTING WITH AN INCREASING INFLUX OF LOW LEVEL
MOISTURE BEING ENTRAINED INTO THE DEVELOPING STORM SYSTEM. THIS
SECOND BURST SHOULD BE GREATEST ACROSS THE GREATER CAPITAL REGION
AND SARATOGA REGION...BERKSHIRES AND SOUTHERN VT...MOST LIKELY
BETWEEN 4 PM AND 7 PM...THEREBY POTENTIALLY ADVERSELY IMPACTING
THE EVENING COMMUTE. WE WILL HAVE TO CLOSELY MONITOR RADAR TRENDS
DURING THIS PERIOD...AS THE ENHANCED F-GEN NOTED ON THE RUC13 FROM
THE CAPITAL REGION EAST INTO THE BERKSHIRES AND SOUTHERN VT
COINCIDES WITH INCREASING MOISTURE/TO NEAR SATURATION/FROM THE
ATLANTIC WITHIN THE 850-700 LAYER...POTENTIALLY ENHANCING BANDING
POTENTIAL AND PERHAPS LEADING TO LOCALLY GREATER SNOWFALL AMTS
THAN CURRENTLY INDICATED.
SINCE NEAR TERM MODELS SUCH AS THE RUC13 AND HRRR HINT AT THIS
SECOND BURST OF SNOW BETWEEN 4 PM AND 7 PM...HAVE EXTENDED THE
WINTER WEATHER ADVISORIES UNTIL 7 PM.
TEMPS TODAY WILL STRUGGLE TO CLIMB INTO AND THROUGH THE TEENS TO
LOWER 20S IN VALLEY AREAS...AND LOWER TO MID TEENS ACROSS HIGHER
ELEVATIONS...WITH MAX TEMPS LIKELY NOT OCCURRING UNTIL BETWEEN 5-7
PM. GIVEN THAT THE CLOUDS WILL BE RATHER LOW...AND THAT MUCH OF
THE PRECIP WILL BE FALLING FROM A LOWER CLOUD DECK INITIALLY THEN
WHAT OCCURRED ON SATURDAY...THE POTENTIAL AND DEPTH OF WET BULB
COOLING WILL BE LESS THAN WHAT OCCURRED THIS PAST SAT. SO...WE
HAVE SIDED WITH THE COOLER SIDE OF A MAV/MET MOS BLEND...BUT DID
NOT STRAY TOO MUCH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
TONIGHT...ANY STEADIER SNOW SHOULD TAPER OFF ACROSS SE VT EARLY.
OTHERWISE...EXPECT SCATTERED SNOW SHOWERS TO OCCUR OVERNIGHT AS
THE MID/UPPER LEVEL TROPOSPHERIC TROUGH AND COLD POOL PASS
THROUGH...WITH 500 MB TEMPS DIPPING INTO THE -35C TO -40C RANGE.
925-700 LAPSE RATES STEEPEN...AND SHOULD ENOUGH MOISTURE BE
PRESENT WITHIN THIS LAYER...COULD LEAD TO SOME EMBEDDED HEAVIER SNOW
SHOWERS AND/OR SQUALLS...LEAVING ADDITIONAL COATINGS...TO PERHAPS
UP TO AN INCH OF SNOWFALL OVERNIGHT. TEMPS SHOULD FALL INTO THE
TEENS IN MOST AREAS.
WED-WED NT...THE AFOREMENTIONED MID LEVEL TROUGH/COLD POOL MOVES E
OF THE REGION IN THE AFTERNOON. HOWEVER...A FAIRLY WELL ALIGNED
WESTERLY FLOW MAY ALLOW FOR LAKE EFFECT SNOWBANDS TO DEVELOP
ACROSS NORTHERN HERKIMER CO IN THE AFTERNOON...AND MAY EXTEND WELL
INTO HAMILTON CO OR EVEN NW WARREN CO FOR A BRIEF TIME LATE IN THE
AFTERNOON INTO EARLY WED NT...AS SUGGESTED PER THE CSTAR FUNDED
INLAND LAKE EXTENT PROGRAM. THIS COULD LEAD TO AT LEAST 1-3 INCHES
OF SNOWFALL...WITH SOME POTENTIAL FOR GREATER AMTS...PERHAPS INTO
THE ADVISORY RANGE. WILL ADDRESS THIS POTENTIAL IN THE HWOALY.
ELSEWHERE...SCATTERED SNOW SHOWERS AND FLURRIES WILL BE POSSIBLE
ACROSS HIGHER ELEVATIONS...WHERE ADDITIONAL MINOR ACCUMS COULD
OCCUR...WITH SOME SNOW SHOWERS/FLURRIES OCCASIONALLY MIGRATING
INTO VALLEY AREAS...ESP NEAR AND N OF THE MOHAWK RIVER. FOR
TEMPS...EXPECT SLIGHTLY MILDER MAX TEMPS WED...REACHING THE 20S TO
LOWER 30S IN VALLEYS...WITH TEENS TO MID 20S ACROSS HIGHER
ELEVATIONS...AND OVERNIGHT MINS WED NT/THU AM FALLING MAINLY INTO
THE TEENS...WITH SOME SINGLE DIGITS POSSIBLE ACROSS NORTHERN AREAS
AND HIGHER ELEVATIONS ACROSS WESTERN NEW ENGLAND.
THU-THU NT...A SOUTHWEST LOW LEVEL FLOW WILL DEVELOP DURING THIS
TIME...ALLOWING FOR GRADUAL MODERATION IN TEMPS. SOME LINGERING
LAKE EFFECT SNOW MAY OCCUR THU ACROSS EXTREME NORTHERN
HERKIMER/HAMILTON COS...BEFORE THE INVERSION LEVEL FALLS.
THEN...SOME WARM ADVECTION PRECIP COULD DEVELOP ACROSS THE WESTERN
DACKS LATE THU NT...IN THE FORM OF LIGHT SNOW...OR EVEN A LIGHT
WINTRY MIX. THU MAX TEMPS SHOULD REACH THE LOWER/MID 30S IN
VALLEYS...AND 20S ACROSS HIGHER ELEVATIONS...WITH OVERNIGHT MINS
THU NT/FRI AM ONLY FALLING INTO THE 20S IN MOST AREAS...WITH TEMPS
POSSIBLY RISING IN SOME AREAS LATE AT NIGHT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
INCREASING AGREEMENT IN THE MODEL AND ENSEMBLE GUIDANCE THROUGH THE
PERIOD. ONE UPPER IMPULSE AND ASSOCIATED FORCING SUPPORTS
PRECIPITATION FRIDAY AND FRIDAY NIGHT. THEN ANOTHER UPPER IMPULSE
AND ASSOCIATED FORCING AFFECTS OUR REGION SATURDAY NIGHT THROUGH
SUNDAY NIGHT. THE TIMING OF THESE SYSTEMS WILL LIKELY GET ADJUSTED
WITH TIME AS THEY ARE WITHIN QUICK WEST SOUTHWEST UPPER CONFLUENT
STEERING FLOW. ALSO...WORDING RAIN AND SNOW THROUGH THE PERIOD SINCE
THERE IS SUCH HIGH UNCERTAINTY IN THE POTENTIAL AREAS OF SLEET
AND/OR FREEZING RAIN.
THE PRECIPITATION TYPES AND THE POSITION OF A POTENTIALLY BROAD
PRECIPITATION TRANSITION ZONE ARE STILL IN QUESTION. HOWEVER...
THERE IS MORE AGREEMENT FOR ANY MIXED PRECIPITATION EARLY FRIDAY
MORNING TO CHANGE TO MAINLY LIQUID PRECIPITATION OVER CENTRAL AND
SOUTHERN AREAS BEFORE COVERAGE OF PRECIPITATION DECREASES FRIDAY
NIGHT. MIXED PRECIPITATION COULD REMAIN MIXED OVER NORTHERN AREAS.
HIGHS FRIDAY IN THE LOWER TO MID 40S IN MANY AREAS WITH MID TO UPPER
30S IN THE HIGHER ELEVATIONS.
LOW LEVEL FORCING WEAKENS FRIDAY NIGHT AND SATURDAY WITH WEAK LOW
LEVEL RIDGING OVER THE REGION. LINGERING MOISTURE AND PROXIMITY TO
THE LOW LEVEL THERMAL GRADIENT AND WIND CONVERGENCE PROXIMATE TO THE
LOW LEVEL BOUNDARY COULD SUPPORT SCATTERED SHOWERS...WITH SOME
FLURRIES OR SNOW SHOWERS. THE BRIEF LOW LEVEL RIDGING COULD ALLOW
TEMPERATURES TO FALL TO NEAR FREEZING IN MANY AREAS FRIDAY NIGHT AND
MID TO UPPER 20S IN THE HIGHER ELEVATIONS... AGAIN SUPPORTING
SCATTERED SHOWERS AND SNOW SHOWERS.
CURRENT GUIDANCE SUGGESTS THE NEXT SYSTEM ARRIVES THROUGH THE DAY
SATURDAY AN CONTINUES SATURDAY NIGHT THROUGH SUNDAY...EXITING SUNDAY
NIGHT. THE WARM ADVECTION AND FORCING LOOK STRONGER WITH THIS
SYSTEM...DRIVING THE WARM AIR FURTHER NORTH...SUPPORTING A
PRECIPITATION TRANSITION TO RAIN IN MOST AREAS. QUITE A STRONG
SOUTHWEST TO WEST SOUTHWEST BOUNDARY LAYER JET TRACKS THROUGH THE
REGION AND THE BOUNDARY LAYER THERMAL GRADIENT IS QUITE TIGHT AS IT
TRACKS EAST AND SOUTH SUNDAY AND SUNDAY NIGHT. SO...WILL HAVE TO
KEEP AN EYE ON WINDS AND POTENTIAL FOR LOCALLY HEAVY RAIN ON THE
MELTING SNOW PACK. HIGHS SATURDAY IN THE LOWER TO MID 40S...LOWER
TO MID 30S HIGHER ELEVATIONS. HIGHS SUNDAY IN THE UPPER 40S TO LOWER
50S...WITH UPPER 30S TO LOWER 40S IN HIGHER ELEVATIONS.
STRONG COLD ADVECTION SPREADS ACROSS THE REGION BY MONDAY MORNING
AND CONTINUES THROUGH THE DAY. SOME LAKE EFFECT SNOW BANDS SHOULD
FORM BUT INLAND EXTENT IS IN QUESTION. HIGHS MONDAY IN THE 20S TO
LOWER 30S.
THERE COULD STILL BE A LOT OF CHANGES TO HOW THESE SYSTEMS DEVELOP
AND IMPACT THE REGION. THERE ARE INDICATIONS OF A POTENTIAL BROAD
MIXED PRECIPITATION TRANSITION ZONE...BUT THE POSITION AND AREAL
EXTENT OF THE PRECIPITATION TRANSITION ZONE KEEPS CHANGING IN
SUCCESSIVE SETS OF GUIDANCE. THERE IS STILL A CHANCE THAT THE
CURRENT INDICATIONS OF MORE RAIN AND LESS WINTERY PRECIPITATION OVER
MUCH OF OUR REGION COULD CHANGE BACK TO COLDER AND MORE MIXED
PRECIPITATION DEPENDING ON HOW THE SYSTEMS DEVELOP IN THE NEXT 3+
DAYS. HOWEVER...THE INCREASING CONSENSUS FROM GUIDANCE OF MORE
LIQUID AND LESS MIXED PRECIPITATION SEEMS THE MOST LIKELY SCENARIO
AT THIS TIME.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
A LOW PRESSURE SYSTEM WILL BRING A WIDESPREAD LIGHT TO MODERATE
SNOWFALL TO THE AREA TODAY. THE SNOW WILL SPREAD NORTHWARD ACROSS
THE AREA DURING THE MORNING AND IS EXPECTED TO TAPER OFF TOWARD THIS
EVENING.
SNOW IS BEGINNING AT KPOU AND WILL SPREAD NORTHWARD TO KALB AND KPSF
BY 13Z-14Z AND BY KGFL BY 14Z. INITIALLY MVFR CONDITIONS ARE
EXPECTED WITH IFR DEVELOPING AS THE SNOW BECOMES STEADIER AS THE
MORNING PROGRESSES. AROUND 5 HOURS OF IFR SNOWS ARE EXPECTED WITH AN
IMPROVE BACK TO MVFR MID TO LATE AFTERNOON. KEEPING VCSH THROUGH
ABOUT 05Z AT ALL TAF SITES WITH LINGERING MOISTURE. AFTER
05Z-06Z...VFR CEILINGS AND VISIBILITIES SHOULD PREVAIL AT ALL TAF
SITES.
WINDS WILL BE NEARLY CALM THROUGH THE MORNING HOURS WITH A LIGHT
SOUTHEASTERLY FLOW DEVELOPING LATER IN THE MORNING AND BECOMING
VARIABLE AGAIN BY LATE AFTERNOON AND EVENING.
OUTLOOK...
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. SCATTERED SHRA...SHSN.
SATURDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
&&
.HYDROLOGY...
A CLIPPER TYPE SYSTEM WILL AFFECT THE REGION TODAY INTO THIS
EVENING. THE PRECIPITATION IS EXPECTED TO BE ALL SNOW WITH THIS
SYSTEM. TOTAL LIQUID EQUIVALENT WITH THIS SYSTEM IS EXPECTED TO
RANGE FROM ONE TO THREE TENTHS OF AN INCH WITH THE HIGHEST AMOUNTS
OVER THE ERN CATSKILLS...W-CNTRL MOHAWK VALLEY...AND WRN NEW
ENGLAND. THIS SYSTEM WILL REDEVELOP SOUTH OF LONG ISLAND...AND
QUICKLY MOVE NORTHEAST OF CAPE COD TOMORROW NIGHT.
SOME LAKE EFFECT SNOW IS POSSIBLE WED-THU WITH LIGHT SNOW
AMOUNTS...AND LIQUID EQUIVALENTS GENERALLY LESS THAN A TENTH OF AN
INCH FOR THE WRN DACKS REGION...AND NRN TIER OF THE HSA.
FOR THE MID WEEK...TEMPS WILL CONTINUE TO BE BELOW NORMAL AND ICE
WILL CONTINUE TO FORM AND THICKEN ON AREA RIVERS...STREAMS AND
PARTICULARLY LAKES.
A MODERATING TREND IN TEMPS IS LIKELY THU INTO FRI...WITH A
FRONTAL BOUNDARY BRINGING SOME SHOWERS TO CLOSE THE WORK WEEK.
SOME SNOW MELT IS LIKELY THIS WEEKEND. ALSO...A STORM SYSTEM
MOVING ALONG A FRONTAL BOUNDARY NEAR THE HSA MAY BRING SIGNIFICANT
PCPN TO THE FORECAST AREA SAT NIGHT INTO SUNDAY WITH EVEN MILDER
TEMPS. THIS WILL CONTINUE TO BE MONITORED FOR THE UPCOMING
WEEKEND.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR CTZ001-
013.
NY...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ054-
058>061-063>066.
MA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MAZ001-
025.
VT...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
VTZ013>015.
&&
$$
SYNOPSIS...KL/WASULA
NEAR TERM...KL
SHORT TERM...KL
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...KL/WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
620 AM EST TUE DEC 17 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM PASSING SOUTH OF THE REGION WILL BRING A
WIDESPREAD LIGHT TO MODERATE SNOWFALL TO THE AREA TODAY. THE SNOW
WILL SPREAD NORTHWARD ACROSS THE AREA DURING THIS MORNING AND IS
EXPECTED TO TAPER OFF THIS EVENING. SCATTERED SNOW SHOWERS ARE
THEN EXPECTED TONIGHT AND WEDNESDAY...ESPECIALLY ACROSS THE HIGHER
TERRAIN. A GRADUAL WARMING TREND IS THEN EXPECTED FOR THE END OF
THE WORKWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 615 AM EST...BITTER COLD REIGNS ACROSS THE REGION...WITH
WIDESPREAD TEMPS OF -10F TO -20F ACROSS THE NORTH COUNTRY...AND -5F
TO +5F ELSEWHERE.
CLOUDS ARE RAPIDLY INCREASING ACROSS CENTRAL AND SOUTHERN
AREAS...WITH A RATHER LOW DECK...WITH CIGS GENERALLY BETWEEN
3500-5000 FT AGL. LIGHT SNOW IS CURRENTLY DEVELOPING THE SE
CATSKILLS/MID HUDSON VALLEY REGION...AND WILL SPREAD ACROSS THE
CAPITAL REGION...SCHOHARIE VALLEY...NW CT AND BERKSHIRES BETWEEN
ROUGHLY 7 AM-10 AM...AND INTO THE MOHAWK VALLEY...THE LAKE
GEORGE/SARATOGA REGION AND SOUTHERN VT BETWEEN 10 AM AND NOON.
ONCE THE SNOW STARTS...WE EXPECT PERIODS OF LIGHT TO MODERATE SNOW
TO CONTINUE THROUGH EARLY THIS EVENING...WITH TOTAL ACCUMS
GENERALLY 2-4 INCHES...EXCEPT FOR 3-6 INCHES ACROSS PORTIONS OF
THE MID HUDSON VALLEY...NW CT...BERKSHIRES...SOUTHERN VT AND SE
CATSKILLS WHERE SOME OROGRAPHIC ENHANCEMENT IS LIKELY...AND 1-3
INCHES ACROSS THE SOUTHERN ADIRONDACKS.
IT APPEARS THAT THERE WILL BE 2 MAIN BURSTS OF SNOW THROUGH
TODAY...THE FIRST ONE BEING DRIVEN MAINLY BY LOW/MID LEVEL WARM
ADVECTION...WHICH WILL BE MAINLY THIS MORNING...THEN PERHAPS THE
BEST BURST OF SNOW LATE THIS AFTERNOON INTO EARLY THIS
EVENING...DUE TO ENHANCED 850-700 FRONTOGENESIS TO THE N/NW OF AN
EMBEDDED SHORTWAVE TRANSLATING JUST S/E OF THE
REGION...INTERACTING WITH AN INCREASING INFLUX OF LOW LEVEL
MOISTURE BEING ENTRAINED INTO THE DEVELOPING STORM SYSTEM. THIS
SECOND BURST SHOULD BE GREATEST ACROSS THE GREATER CAPITAL REGION
AND SARATOGA REGION...BERKSHIRES AND SOUTHERN VT...MOST LIKELY
BETWEEN 4 PM AND 7 PM...THEREBY POTENTIALLY ADVERSELY IMPACTING
THE EVENING COMMUTE. WE WILL HAVE TO CLOSELY MONITOR RADAR TRENDS
DURING THIS PERIOD...AS THE ENHANCED F-GEN NOTED ON THE RUC13 FROM
THE CAPITAL REGION EAST INTO THE BERKSHIRES AND SOUTHERN VT
COINCIDES WITH INCREASING MOISTURE/TO NEAR SATURATION/FROM THE
ATLANTIC WITHIN THE 850-700 LAYER...POTENTIALLY ENHANCING BANDING
POTENTIAL AND PERHAPS LEADING TO LOCALLY GREATER SNOWFALL AMTS
THAN CURRENTLY INDICATED.
SINCE NEAR TERM MODELS SUCH AS THE RUC13 AND HRRR HINT AT THIS
SECOND BURST OF SNOW BETWEEN 4 PM AND 7 PM...HAVE EXTENDED THE
WINTER WEATHER ADVISORIES UNTIL 7 PM.
TEMPS TODAY WILL STRUGGLE TO CLIMB INTO AND THROUGH THE TEENS TO
LOWER 20S IN VALLEY AREAS...AND LOWER TO MID TEENS ACROSS HIGHER
ELEVATIONS...WITH MAX TEMPS LIKELY NOT OCCURRING UNTIL BETWEEN 5-7
PM. GIVEN THAT THE CLOUDS WILL BE RATHER LOW...AND THAT MUCH OF
THE PRECIP WILL BE FALLING FROM A LOWER CLOUD DECK INITIALLY THEN
WHAT OCCURRED ON SATURDAY...THE POTENTIAL AND DEPTH OF WET BULB
COOLING WILL BE LESS THAN WHAT OCCURRED THIS PAST SAT. SO...WE
HAVE SIDED WITH THE COOLER SIDE OF A MAV/MET MOS BLEND...BUT DID
NOT STRAY TOO MUCH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
TONIGHT...ANY STEADIER SNOW SHOULD TAPER OFF ACROSS SE VT EARLY.
OTHERWISE...EXPECT SCATTERED SNOW SHOWERS TO OCCUR OVERNIGHT AS
THE MID/UPPER LEVEL TROPOSPHERIC TROUGH AND COLD POOL PASS
THROUGH...WITH 500 MB TEMPS DIPPING INTO THE -35C TO -40C RANGE.
925-700 LAPSE RATES STEEPEN...AND SHOULD ENOUGH MOISTURE BE
PRESENT WITHIN THIS LAYER...COULD LEAD TO SOME EMBEDDED HEAVIER SNOW
SHOWERS AND/OR SQUALLS...LEAVING ADDITIONAL COATINGS...TO PERHAPS
UP TO AN INCH OF SNOWFALL OVERNIGHT. TEMPS SHOULD FALL INTO THE
TEENS IN MOST AREAS.
WED-WED NT...THE AFOREMENTIONED MID LEVEL TROUGH/COLD POOL MOVES E
OF THE REGION IN THE AFTERNOON. HOWEVER...A FAIRLY WELL ALIGNED
WESTERLY FLOW MAY ALLOW FOR LAKE EFFECT SNOWBANDS TO DEVELOP
ACROSS NORTHERN HERKIMER CO IN THE AFTERNOON...AND MAY EXTEND WELL
INTO HAMILTON CO OR EVEN NW WARREN CO FOR A BRIEF TIME LATE IN THE
AFTERNOON INTO EARLY WED NT...AS SUGGESTED PER THE CSTAR FUNDED
INLAND LAKE EXTENT PROGRAM. THIS COULD LEAD TO AT LEAST 1-3 INCHES
OF SNOWFALL...WITH SOME POTENTIAL FOR GREATER AMTS...PERHAPS INTO
THE ADVISORY RANGE. WILL ADDRESS THIS POTENTIAL IN THE HWOALY.
ELSEWHERE...SCATTERED SNOW SHOWERS AND FLURRIES WILL BE POSSIBLE
ACROSS HIGHER ELEVATIONS...WHERE ADDITIONAL MINOR ACCUMS COULD
OCCUR...WITH SOME SNOW SHOWERS/FLURRIES OCCASIONALLY MIGRATING
INTO VALLEY AREAS...ESP NEAR AND N OF THE MOHAWK RIVER. FOR
TEMPS...EXPECT SLIGHTLY MILDER MAX TEMPS WED...REACHING THE 20S TO
LOWER 30S IN VALLEYS...WITH TEENS TO MID 20S ACROSS HIGHER
ELEVATIONS...AND OVERNIGHT MINS WED NT/THU AM FALLING MAINLY INTO
THE TEENS...WITH SOME SINGLE DIGITS POSSIBLE ACROSS NORTHERN AREAS
AND HIGHER ELEVATIONS ACROSS WESTERN NEW ENGLAND.
THU-THU NT...A SOUTHWEST LOW LEVEL FLOW WILL DEVELOP DURING THIS
TIME...ALLOWING FOR GRADUAL MODERATION IN TEMPS. SOME LINGERING
LAKE EFFECT SNOW MAY OCCUR THU ACROSS EXTREME NORTHERN
HERKIMER/HAMILTON COS...BEFORE THE INVERSION LEVEL FALLS.
THEN...SOME WARM ADVECTION PRECIP COULD DEVELOP ACROSS THE WESTERN
DACKS LATE THU NT...IN THE FORM OF LIGHT SNOW...OR EVEN A LIGHT
WINTRY MIX. THU MAX TEMPS SHOULD REACH THE LOWER/MID 30S IN
VALLEYS...AND 20S ACROSS HIGHER ELEVATIONS...WITH OVERNIGHT MINS
THU NT/FRI AM ONLY FALLING INTO THE 20S IN MOST AREAS...WITH TEMPS
POSSIBLY RISING IN SOME AREAS LATE AT NIGHT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
INCREASING AGREEMENT IN THE MODEL AND ENSEMBLE GUIDANCE THROUGH THE
PERIOD. ONE UPPER IMPULSE AND ASSOCIATED FORCING SUPPORTS
PRECIPITATION FRIDAY AND FRIDAY NIGHT. THEN ANOTHER UPPER IMPULSE
AND ASSOCIATED FORCING AFFECTS OUR REGION SATURDAY NIGHT THROUGH
SUNDAY NIGHT. THE TIMING OF THESE SYSTEMS WILL LIKELY GET ADJUSTED
WITH TIME AS THEY ARE WITHIN QUICK WEST SOUTHWEST UPPER CONFLUENT
STEERING FLOW. ALSO...WORDING RAIN AND SNOW THROUGH THE PERIOD SINCE
THERE IS SUCH HIGH UNCERTAINTY IN THE POTENTIAL AREAS OF SLEET
AND/OR FREEZING RAIN.
THE PRECIPITATION TYPES AND THE POSITION OF A POTENTIALLY BROAD
PRECIPITATION TRANSITION ZONE ARE STILL IN QUESTION. HOWEVER...
THERE IS MORE AGREEMENT FOR ANY MIXED PRECIPITATION EARLY FRIDAY
MORNING TO CHANGE TO MAINLY LIQUID PRECIPITATION OVER CENTRAL AND
SOUTHERN AREAS BEFORE COVERAGE OF PRECIPITATION DECREASES FRIDAY
NIGHT. MIXED PRECIPITATION COULD REMAIN MIXED OVER NORTHERN AREAS.
HIGHS FRIDAY IN THE LOWER TO MID 40S IN MANY AREAS WITH MID TO UPPER
30S IN THE HIGHER ELEVATIONS.
LOW LEVEL FORCING WEAKENS FRIDAY NIGHT AND SATURDAY WITH WEAK LOW
LEVEL RIDGING OVER THE REGION. LINGERING MOISTURE AND PROXIMITY TO
THE LOW LEVEL THERMAL GRADIENT AND WIND CONVERGENCE PROXIMATE TO THE
LOW LEVEL BOUNDARY COULD SUPPORT SCATTERED SHOWERS...WITH SOME
FLURRIES OR SNOW SHOWERS. THE BRIEF LOW LEVEL RIDGING COULD ALLOW
TEMPERATURES TO FALL TO NEAR FREEZING IN MANY AREAS FRIDAY NIGHT AND
MID TO UPPER 20S IN THE HIGHER ELEVATIONS... AGAIN SUPPORTING
SCATTERED SHOWERS AND SNOW SHOWERS.
CURRENT GUIDANCE SUGGESTS THE NEXT SYSTEM ARRIVES THROUGH THE DAY
SATURDAY AN CONTINUES SATURDAY NIGHT THROUGH SUNDAY...EXITING SUNDAY
NIGHT. THE WARM ADVECTION AND FORCING LOOK STRONGER WITH THIS
SYSTEM...DRIVING THE WARM AIR FURTHER NORTH...SUPPORTING A
PRECIPITATION TRANSITION TO RAIN IN MOST AREAS. QUITE A STRONG
SOUTHWEST TO WEST SOUTHWEST BOUNDARY LAYER JET TRACKS THROUGH THE
REGION AND THE BOUNDARY LAYER THERMAL GRADIENT IS QUITE TIGHT AS IT
TRACKS EAST AND SOUTH SUNDAY AND SUNDAY NIGHT. SO...WILL HAVE TO
KEEP AN EYE ON WINDS AND POTENTIAL FOR LOCALLY HEAVY RAIN ON THE
MELTING SNOW PACK. HIGHS SATURDAY IN THE LOWER TO MID 40S...LOWER
TO MID 30S HIGHER ELEVATIONS. HIGHS SUNDAY IN THE UPPER 40S TO LOWER
50S...WITH UPPER 30S TO LOWER 40S IN HIGHER ELEVATIONS.
STRONG COLD ADVECTION SPREADS ACROSS THE REGION BY MONDAY MORNING
AND CONTINUES THROUGH THE DAY. SOME LAKE EFFECT SNOW BANDS SHOULD
FORM BUT INLAND EXTENT IS IN QUESTION. HIGHS MONDAY IN THE 20S TO
LOWER 30S.
THERE COULD STILL BE A LOT OF CHANGES TO HOW THESE SYSTEMS DEVELOP
AND IMPACT THE REGION. THERE ARE INDICATIONS OF A POTENTIAL BROAD
MIXED PRECIPITATION TRANSITION ZONE...BUT THE POSITION AND AREAL
EXTENT OF THE PRECIPITATION TRANSITION ZONE KEEPS CHANGING IN
SUCCESSIVE SETS OF GUIDANCE. THERE IS STILL A CHANCE THAT THE
CURRENT INDICATIONS OF MORE RAIN AND LESS WINTERY PRECIPITATION OVER
MUCH OF OUR REGION COULD CHANGE BACK TO COLDER AND MORE MIXED
PRECIPITATION DEPENDING ON HOW THE SYSTEMS DEVELOP IN THE NEXT 3+
DAYS. HOWEVER...THE INCREASING CONSENSUS FROM GUIDANCE OF MORE
LIQUID AND LESS MIXED PRECIPITATION SEEMS THE MOST LIKELY SCENARIO
AT THIS TIME.
&&
.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL SHIFT EASTWARD ACROSS THE THROUGH THE EARLY
MORNING HOURS. A LOW PRESSURE SYSTEM WILL BRING A WIDESPREAD LIGHT
TO MODERATE SNOWFALL TO THE AREA TODAY. THE SNOW WILL SPREAD
NORTHWARD ACROSS THE AREA DURING THE MORNING AND IS EXPECTED TO
TAPER OFF BY LATE AFTERNOON.
EXPECTING VFR CONDITIONS TO PREVAIL THROUGH THE EARLY MORNING HOURS.
CLOUDS WILL STREAM IN TOWARD SUNRISE...THICKENING AND LOWERING
QUICKLY THROUGH THE MORNING AS THE WARM ADVECTION SNOWFALL MOVES IN.
SNOW IS EXPECTED TO COMMENCE AT KPOU AROUND SUNRISE AND SPREAD
NORTHWARD TO KALB AND KPSF BY MID MORNING AND BY KGFL BY LATE
MORNING. INITIALLY MVFR CONDITIONS ARE EXPECTED WITH IFR DEVELOPING
AS THE SNOW BECOMES STEADIER AS THE MORNING PROGRESSES. AROUND 5
HOURS OF IFR SNOWS ARE EXPECTED WITH AN IMPROVE BACK TO MVFR MID TO
LATE AFTERNOON.
WINDS WILL BE NEARLY CALM THROUGH THE EARLY MORNING HOURS WITH A
LIGHT SOUTHEASTERLY FLOW DEVELOPING LATER IN THE MORNING AND
BECOMING VARIABLE AGAIN BY LATE AFTERNOON AND EVENING.
OUTLOOK...
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. SCATTERED SHRA...SHSN.
SATURDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
&&
.HYDROLOGY...
A CLIPPER TYPE SYSTEM WILL AFFECT THE REGION TODAY INTO THIS
EVENING. THE PRECIPITATION IS EXPECTED TO BE ALL SNOW WITH THIS
SYSTEM. TOTAL LIQUID EQUIVALENT WITH THIS SYSTEM IS EXPECTED TO
RANGE FROM ONE TO THREE TENTHS OF AN INCH WITH THE HIGHEST AMOUNTS
OVER THE ERN CATSKILLS...W-CNTRL MOHAWK VALLEY...AND WRN NEW
ENGLAND. THIS SYSTEM WILL REDEVELOP SOUTH OF LONG ISLAND...AND
QUICKLY MOVE NORTHEAST OF CAPE COD TOMORROW NIGHT.
SOME LAKE EFFECT SNOW IS POSSIBLE WED-THU WITH LIGHT SNOW
AMOUNTS...AND LIQUID EQUIVALENTS GENERALLY LESS THAN A TENTH OF AN
INCH FOR THE WRN DACKS REGION...AND NRN TIER OF THE HSA.
FOR THE MID WEEK...TEMPS WILL CONTINUE TO BE BELOW NORMAL AND ICE
WILL CONTINUE TO FORM AND THICKEN ON AREA RIVERS...STREAMS AND
PARTICULARLY LAKES.
A MODERATING TREND IN TEMPS IS LIKELY THU INTO FRI...WITH A
FRONTAL BOUNDARY BRINGING SOME SHOWERS TO CLOSE THE WORK WEEK.
SOME SNOW MELT IS LIKELY THIS WEEKEND. ALSO...A STORM SYSTEM
MOVING ALONG A FRONTAL BOUNDARY NEAR THE HSA MAY BRING SIGNIFICANT
PCPN TO THE FORECAST AREA SAT NIGHT INTO SUNDAY WITH EVEN MILDER
TEMPS. THIS WILL CONTINUE TO BE MONITORED FOR THE UPCOMING
WEEKEND.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR CTZ001-
013.
NY...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ054-
058>061-063>066.
MA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MAZ001-
025.
VT...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
VTZ013>015.
&&
$$
SYNOPSIS...KL/WASULA
NEAR TERM...KL
SHORT TERM...KL
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...KL/WASULA
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1058 AM EST TUE DEC 17 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHERN STATES WILL SLIP WESTWARD THIS
AFTERNOON ALLOWING A MOISTURE STARVED COLD FRONT TO CROSS OUR AREA
THIS EVENING. HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY
THEN SLIDE OFF THE SOUTHEAST COAST THURSDAY. A SOUTHERLY FLOW WILL
BRING MUCH ABOVE NORMAL TEMPERATURES TO THE AREA FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE STRETCHED ACROSS THE GULF COAST STATES LATE THIS
MORNING WITH A COLD FRONT EXTENDING FROM PA THROUGH KY TO AR. OUR
AIR MASS REMAINED DRY WITH PWAT LESS THAN 0.50 INCHES. STILL
EXPECT CLEAR SKIES TO HOLD ACROSS THE AREA. THE FRONT WILL MOVE
THROUGH THE FORECAST AREA EARLY TONIGHT.
IT WILL BE WARM AND BREEZY AHEAD OF THE FRONT THIS AFTERNOON. THE
NAM BUFKIT MOMENTUM TRANSFER TOOL SUPPORTS GUSTS AROUND 20 KNOTS.
THE 10Z HRRR INDICATES GUSTS OF 20 TO 25 KNOTS. LEANED TOWARD THE
WARMER TEMPERATURE GUIDANCE THIS AFTERNOON GIVEN DRY AIR MASS AND
WARMING JUST AHEAD OF THE COLD FRONT. KEPT HIGHS IN THE LOW/MID
60S. THERE WILL BE MIXING FOR MUCH OF TONIGHT WHICH SHOULD HELP
HOLD UP TEMPERATURES. HOWEVER... THE GRADIENT SHOULD RELAX TOWARD
SUNRISE. USED THE GUIDANCE CONSENSUS FOR THE LOW TEMPERATURE
FORECAST IN THE LOW/MID 30S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BE MOVING INTO THE FORECAST AREA FROM THE WEST
WEDNESDAY. EXPECT CLEAR SKIES. THE TEMPERATURE GUIDANCE WAS
CONSISTENT. THE HIGH WILL BE CENTERED OVER THE AREA WEDNESDAY
NIGHT. THERE MAY BE SOME HIGH CLOUDINESS AS THE UPPER RIDGE
FLATTENS BUT EXPECT THIS CLOUDINESS WILL BE THIN AND STRONG NET
RADIATIONAL COOLING SHOULD OCCUR. WE LEANED TOWARD THE COOLER
TEMPERATURE GUIDANCE. WARMING SHOULD BEGIN THURSDAY AS THE HIGH
SHIFTS OFF THE COAST AND A SOUTHERLY FLOW DEVELOPS. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
RETURN FLOW ON THE WEST SIDE OF HIGH PRESSURE OFF THE SOUTHEAST
COAST WILL BRING INCREASING MOISTURE AND WARMER TEMPERATURES TO
THE AREA INTO THE WEEKEND. MUCH ABOVE NORMAL TEMPERATURES ARE
EXPECTED BY SUNDAY WITH MORNING LOWS NEAR 60 AND HIGHS IN THE MID
TO UPPER 70S. A COLD FRONT WILL APPROACH THE AREA FROM THE WEST ON
SUNDAY AND CROSS THE AREA SUNDAY NIGHT INTO MONDAY. WILL INCREASE
POPS TO THE 60 TO 70 PERCENT RANGE WITH THE FRONTAL PASSAGE. WITH
WARM MOIST AIR AT LOW LEVELS...A 40 TO 50 KT LOW LEVEL JET...AND
SLIGHTLY UNSTABLE LI VALUES...SOME CONVECTION IS POSSIBLE WITH
THIS FRONTAL PASSAGE. WILL HAVE TO WATCH THIS AS WE GET CLOSER TO
THE EVENT. DRIER AND COLDER AIR WILL MOVE IN BEHIND THE FRONT
MONDAY AFTERNOON INTO TUESDAY
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE FORECAST PERIOD.
DRY AIR MASS IN PLACE FOR CLEAR SKIES. WINDS BEGINNING TO
INCREASE AT 15Z AS STRONGER WINDS ALOFT MIX DOWN TO THE SURFACE
AHEAD OF AN APPROACHING FRONT. SOME OF THE STRONGER GUSTS MAY
REACH 20 KNOTS LATE THIS MORNING INTO THE AFTERNOON. SOUTHWEST
WINDS THIS AFTERNOON WILL DECREASE BEFORE SHIFTING WEST 18/01Z
THROUGH 18/03Z AS A COLD FRONT MOVES THROUGH THE TAF SITES.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1031 AM EST TUE DEC 17 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHERN STATES WILL SLIP WESTWARD THIS
AFTERNOON ALLOWING A MOISTURE STARVED COLD FRONT TO CROSS OUR AREA
THIS EVENING. HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY
THEN SLIDE OFF THE SOUTHEAST COAST THURSDAY. A SOUTHERLY FLOW WILL
BRING ABOVE NORMAL TEMPERATURES TO THE AREA FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE STRETCHED ACROSS THE GULF COAST STATES LATE THIS
MORNING WITH A COLD FRONT EXTENDING FROM PA THROUGH KY TO AR. OUR
AIR MASS REMAINED DRY WITH PWAT LESS THAN 0.50 INCHES. STILL
EXPECT CLEAR SKIES TO HOLD ACROSS THE AREA. THE FRONT WILL MOVE
THROUGH THE FORECAST AREA EARLY TONIGHT.
IT WILL BE WARM AND BREEZY AHEAD OF THE FRONT THIS AFTERNOON. THE
NAM BUFKIT MOMENTUM TRANSFER TOOL SUPPORTS GUSTS AROUND 20 KNOTS.
THE 10Z HRRR INDICATES GUSTS OF 20 TO 25 KNOTS. LEANED TOWARD THE
WARMER TEMPERATURE GUIDANCE THIS AFTERNOON GIVEN DRY AIR MASS AND
WARMING JUST AHEAD OF THE COLD FRONT. KEPT HIGHS IN THE LOW/MID
60S. THERE WILL BE MIXING FOR MUCH OF TONIGHT WHICH SHOULD HELP
HOLD UP TEMPERATURES. HOWEVER... THE GRADIENT SHOULD RELAX TOWARD
SUNRISE. USED THE GUIDANCE CONSENSUS FOR THE LOW TEMPERATURE
FORECAST IN THE LOW/MID 30S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BE MOVING INTO THE FORECAST AREA FROM THE WEST
WEDNESDAY. EXPECT CLEAR SKIES. THE TEMPERATURE GUIDANCE WAS
CONSISTENT. THE HIGH WILL BE CENTERED OVER THE AREA WEDNESDAY
NIGHT. THERE MAY BE SOME HIGH CLOUDINESS AS THE UPPER RIDGE
FLATTENS BUT EXPECT THIS CLOUDINESS WILL BE THIN AND STRONG NET
RADIATIONAL COOLING SHOULD OCCUR. WE LEANED TOWARD THE COOLER
TEMPERATURE GUIDANCE. WARMING SHOULD BEGIN THURSDAY AS THE HIGH
SHIFTS OFF THE COAST AND A SOUTHERLY FLOW DEVELOPS. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE OFFSHORE HIGH WILL CIRCULATE INCREASING MOISTURE INTO THE
FORECAST AREA LATE IN THE WEEK AHEAD OF THE SLOW MOVING COLD
FRONT. THERE MAY BE ENOUGH MOISTURE AND ISENTROPIC LIFT FOR
SHOWERS FRIDAY AND SATURDAY BUT WITH THE MAIN FORCING ASSOCIATED
WITH THE FRONT STILL TO THE WEST THE CHANCE SHOULD BE LOW. THE
COLD FRONT APPEARS TO BECOME PARALLEL TO THE UPPER FLOW FRIDAY
NIGHT THROUGH SATURDAY WITH THE FRONT MAKING LITTLE EASTWARD
PROGRESS. THE MEDIUM-RANGE MODELS BRING THE FRONT ACROSS OUR AREA
SUNDAY NIGHT AND MONDAY. THE GFS ENSEMBLE MEANS INDICATE ABOVE
NORMAL POPS SATURDAY THROUGH MONDAY BUT WITH HIGH SPREADS. GIVEN
EXPECTED FRONTAL PASSAGE MONDAY...WE FORECASTED THE HIGHEST POPS
SUNDAY NIGHT INTO MONDAY.
TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE WEEKEND WITH HIGHS IN
THE 70S AND LOWS IN THE UPPER 50S AND LOWER 60S.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE FORECAST PERIOD.
DRY AIR MASS IN PLACE FOR CLEAR SKIES. WINDS BEGINNING TO
INCREASE AT 15Z AS STRONGER WINDS ALOFT MIX DOWN TO THE SURFACE
AHEAD OF AN APPROACHING FRONT. SOME OF THE STRONGER GUSTS MAY
REACH 20 KNOTS LATE THIS MORNING INTO THE AFTERNOON. SOUTHWEST
WINDS THIS AFTERNOON WILL DECREASE BEFORE SHIFTING WEST 18/01Z
THROUGH 18/03Z AS A COLD FRONT MOVES THROUGH THE TAF SITES.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
639 AM EST TUE DEC 17 2013
.SYNOPSIS...
A PRESSURE RIDGE WILL BE SOUTH OF THE FORECAST AREA TODAY. THE
RIDGE WILL LIMIT MOISTURE AHEAD OF AN APPROACHING COLD FRONT. THE
DRY FRONT WILL MOVE THROUGH THE FORECAST AREA TONIGHT. HIGH
PRESSURE MOVING INTO THE REGION BEHIND THE FRONT WEDNESDAY WILL BE
CENTERED OVER THE AREA WEDNESDAY NIGHT AND OFF THE SOUTHEAST COAST
THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE PRESSURE RIDGE SOUTH OF THE FORECAST AREA WILL BLOCK A RETURN
OF MOISTURE FROM THE GULF OF MEXICO AHEAD OF THE APPROACHING COLD
FRONT. THE FRONT WILL MOVE THROUGH THE FORECAST AREA TONIGHT. IT
WILL BE WARM AND BREEZY AHEAD OF THE FRONT THIS AFTERNOON. THE NAM
BUFKIT MOMENTUM TRANSFER TOOL SUPPORTS GUSTS AROUND 20 KNOTS. THE
07Z HRRR INDICATES GUSTS OF 20 TO 25 KNOTS. LEANED TOWARD THE
WARMER TEMPERATURE GUIDANCE TODAY BECAUSE OF THE DRY AIR MASS AND
WARMING JUST AHEAD OF THE COLD FRONT. THERE WILL BE MIXING FOR
MUCH OF TONIGHT WHICH SHOULD HELP HOLD UP TEMPERATURES. HOWEVER...
THE GRADIENT SHOULD RELAX TOWARD SUNRISE. USED THE GUIDANCE
CONSENSUS FOR THE LOW TEMPERATURE FORECAST.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BE MOVING INTO THE FORECAST AREA FROM THE WEST
WEDNESDAY. EXPECT CLEAR SKIES. THE TEMPERATURE GUIDANCE WAS
CONSISTENT. THE HIGH WILL BE CENTERED OVER THE AREA WEDNESDAY
NIGHT. THERE MAY BE SOME HIGH CLOUDINESS AS THE UPPER RIDGE
FLATTENS BUT EXPECT THIS CLOUDINESS WILL BE THIN AND STRONG NET
RADIATIONAL COOLING SHOULD OCCUR. WE LEANED TOWARD THE COOLER
TEMPERATURE GUIDANCE. WARMING SHOULD BEGIN THURSDAY AS THE HIGH
SHIFTS OFF THE COAST AND A SOUTHERLY FLOW DEVELOPS. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE OFFSHORE HIGH WILL CIRCULATE INCREASING MOISTURE INTO THE
FORECAST AREA LATE IN THE WEEK AHEAD OF THE SLOW MOVING COLD
FRONT. THERE MAY BE ENOUGH MOISTURE AND ISENTROPIC LIFT FOR
SHOWERS FRIDAY AND SATURDAY BUT WITH THE MAIN FORCING ASSOCIATED
WITH THE FRONT STILL TO THE WEST THE CHANCE SHOULD BE LOW. THE
COLD FRONT APPEARS TO BECOME PARALLEL TO THE UPPER FLOW FRIDAY
NIGHT THROUGH SATURDAY WITH THE FRONT MAKING LITTLE EASTWARD
PROGRESS. THE MEDIUM-RANGE MODELS BRING THE FRONT ACROSS OUR AREA
SUNDAY NIGHT AND MONDAY. THE GFS ENSEMBLE MEANS INDICATE ABOVE
NORMAL POPS SATURDAY THROUGH MONDAY BUT WITH HIGH SPREADS. GIVEN
EXPECTED FRONTAL PASSAGE MONDAY...WE FORECASTED THE HIGHEST POPS
SUNDAY NIGHT INTO MONDAY.
TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE WEEKEND WITH HIGHS IN
THE 70S AND LOWS IN THE UPPER 50S AND LOWER 60S.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE FORECAST PERIOD.
DRY HIGH PRESSURE CONTINUES TO DOMINATE OVER THE AREA. DRY AIR
AND LIGHT WINDS WILL HELP TO LIMIT FOG DEVELOPMENT. WINDS WILL
INCREASE DURING THE DAY AS STRONGER WINDS ALOFT MIX DOWN TO THE
SURFACE AHEAD OF AN APPROACHING FRONT. SOME OF THE STRONGER GUSTS
MAY REACH 20 KNOTS DURING THE LATE MORNING AND EARLY AFTERNOON
HOURS.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
518 AM EST TUE DEC 17 2013
.SYNOPSIS...
A PRESSURE RIDGE WILL BE SOUTH OF THE FORECAST AREA TODAY. THE
RIDGE WILL LIMIT MOISTURE AHEAD OF AN APPROACHING COLD FRONT. THE
DRY FRONT WILL MOVE THROUGH THE FORECAST AREA TONIGHT. HIGH
PRESSURE MOVING INTO THE REGION BEHIND THE FRONT WEDNESDAY WILL BE
CENTERED OVER THE AREA WEDNESDAY NIGHT AND OFF THE SOUTHEAST COAST
THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE PRESSURE RIDGE SOUTH OF THE FORECAST AREA WILL BLOCK A RETURN
OF MOISTURE FROM THE GULF OF MEXICO AHEAD OF THE APPROACHING COLD
FRONT. THE FRONT WILL MOVE THROUGH THE FORECAST AREA TONIGHT. IT
WILL BE WARM AND BREEZY AHEAD OF THE FRONT THIS AFTERNOON. THE NAM
BUFKIT MOMENTUM TRANSFER TOOL SUPPORTS GUSTS AROUND 20 KNOTS. THE
07Z HRRR INDICATES GUSTS OF 20 TO 25 KNOTS. LEANED TOWARD THE
WARMER TEMPERATURE GUIDANCE TODAY BECAUSE OF THE DRY AIR MASS AND
WARMING JUST AHEAD OF THE COLD FRONT. THERE WILL BE MIXING FOR
MUCH OF TONIGHT WHICH SHOULD HELP HOLD UP TEMPERATURES. HOWEVER...
THE GRADIENT SHOULD RELAX TOWARD SUNRISE. USED THE GUIDANCE
CONSENSUS FOR THE LOW TEMPERATURE FORECAST.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BE MOVING INTO THE FORECAST AREA FROM THE WEST
WEDNESDAY. EXPECT CLEAR SKIES. THE TEMPERATURE GUIDANCE WAS
CONSISTENT. THE HIGH WILL BE CENTERED OVER THE AREA WEDNESDAY
NIGHT. THERE MAY BE SOME HIGH CLOUDINESS AS THE UPPER RIDGE
FLATTENS BUT EXPECT THIS CLOUDINESS WILL BE THIN AND STRONG NET
RADIATIONAL COOLING SHOULD OCCUR. WE LEANED TOWARD THE COOLER
TEMPERATURE GUIDANCE. WARMING SHOULD BEGIN THURSDAY AS THE HIGH
SHIFTS OFF THE COAST AND A SOUTHERLY FLOW DEVELOPS. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE OFFSHORE HIGH WILL CIRCULATE INCREASING MOISTURE INTO THE
FORECAST AREA LATE IN THE WEEK AHEAD OF THE SLOW MOVING COLD
FRONT. THERE MAY BE ENOUGH MOISTURE AND ISENTROPIC LIFT FOR
SHOWERS FRIDAY AND SATURDAY BUT WITH THE MAIN FORCING ASSOCIATED
WITH THE FRONT STILL TO THE WEST THE CHANCE SHOULD BE LOW. THE
COLD FRONT APPEARS TO BECOME PARALLEL TO THE UPPER FLOW FRIDAY
NIGHT THROUGH SATURDAY WITH THE FRONT MAKING LITTLE EASTWARD
PROGRESS. THE MEDIUM-RANGE MODELS BRING THE FRONT ACROSS OUR AREA
SUNDAY NIGHT AND MONDAY. THE GFS ENSEMBLE MEANS INDICATE ABOVE
NORMAL POPS SATURDAY THROUGH MONDAY BUT WITH HIGH SPREADS. GIVEN
EXPECTED FRONTAL PASSAGE MONDAY...WE FORECASTED THE HIGHEST POPS
SUNDAY NIGHT INTO MONDAY.
TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE WEEKEND WITH HIGHS IN
THE 70S AND LOWS IN THE UPPER 50S AND LOWER 60S.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE FORECAST PERIOD.
DRY HIGH PRESSURE CONTINUES TO DOMINATE OVER THE AREA. THE
COMBINATION OF A DRY AIR MASS AND A LOW-LEVEL JET AROUND 25 KNOTS
JET OVERNIGHT WILL KEEP WINDS JUST OFF THE SURFACE UP ENOUGH TO
HELP INHIBIT FOG DEVELOPMENT. LOW LEVEL WIND SHEAR MIGHT BE A
CONCERN TOWARDS 12Z BUT CONFIDENCE OF MEETING THE 30 KNOT
THRESHOLD IS NOT HIGH ENOUGH TO INCLUDE IN THIS FORECAST. WINDS
WILL INCREASE DURING THE DAY TUESDAY AHEAD OF AN APPROACHING
FRONT...AND THERE COULD BE SOME STRONGER GUSTS AROUND 20 KNOTS
DURING THE LATE MORNING AND EARLY AFTERNOON HOURS.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
840 AM CST TUE DEC 17 2013
.DISCUSSION...
328 AM CST
TODAY...
MAIN CONCERNS WILL BE FOCUSED ON THE MID-LVL WAVE THAT IS QUICKLY
SLIDING EAST ACROSS THE WESTERN GREAT LAKES...POSSIBLY BRINGING A
SLUG OF LGT SNOW TO NORTH/NORTHEAST IL AND NORTHWEST IN THIS MORNING
THRU MIDDAY. THEN THE POTENTIAL FOR SOME BLOWING SNOW AS THE
GRADIENT RAMPS UP MIDDAY AND MIXING JUMPS TO ARND 3KFT AGL.
IR IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS THE REGION...AND
SOME COOLING WITH CLOUD TOPS WITH THE WEAK WAVE SLIDING EAST ACROSS
WESTCENTRAL WISC EARLY THIS MORNING. KARX RADAR INDICATES AN AREA OF
RETURNS ACROSS THIS AREA...HOWEVER THE RECENT COUPLE OF HOURS HAVE
INDICATED SOME DOWNWARD TREND IN THE SOUTHERN PORTION OF THIS
PRECIP. SFC OBS ARE NOT INDICATING ANY SNOW IN FAR SOUTHEAST MN AND
HAS TENDED TO BE FOCUSED FURTHER NORTH. BASED ON CURRENT
TRAJECTORY...THE BEST LGT SNOW MAY END UP HOLDING FURTHER NORTH INTO
WISC. BUFR PROFILES HAVE BACKED OFF ON THE OMEGA PLACEMENT...HOWEVER
A HANDFUL OF POINTS CONTINUE TO INDICATE SOME DEGREE OF LIFT THROUGH
THE FAVORED DGZ ARND 12-15Z. DPROG/DT OF THE BUFR SITES ALSO
INDICATES A DOWNWARD TREND...SUPPORTING THE LOWER CONFIDENCE IN SNOW
TOTALS. THE CAVEAT AND CHALLENGE IS THE NARROW CHANNEL OF MOISTURE
THAT STRETCHES WEST AND RECENT RAP GUIDANCE HAS INDICATED AN
ENHANCEMENT TO THIS FEATURE AS IT PIVOTS EAST ACROSS THE CWFA THIS
MORNING.
SNOWFALL RATIOS SHOULD FALL AROUND 20:1...SO RATHER DRY.
BASED ON COBB OUTPUT FROM THESE PROFILES SNOWFALL SHUD GENERALLY
FALL BETWEEN A FEW TENTHS TO 1". COULD SEE AREAS CLOSEST TO THE
WISCONSIN STATELINE PICKING UP SLIGHTLY MORE OR WITHIN A 1-2" RANGE.
THE WAVE WILL REMAIN PROGRESSIVE AND SHUD COME TO AN END BY 15-17Z
FROM WEST TO EAST...AS WIND GUSTS BEGIN TO DEVELOP. ANY FRESH
SNOWFALL SHUD EASILY BLOW AROUND. THIS MAY BE MORE FOCUSED ACROSS
AREAS NORTH OF I-80...AS THE PATCHY DZ EARLY THIS MORNING WILL
MOISTEN UP THE SNOW FURTHER SOUTH AND LIMIT THE ABILITY FOR THE SNOW
TO BLOW AROUND.
TEMPS WILL BEGIN TO REBOUND TDY...AS THE 500MB TROUGH AXIS BEGINS TO
PUSH EAST OF THE WESTERN GREAT LAKES. TEMPS WILL STEADILY WARM INTO
THE UPR 20S TO ARND 30 ACROSS THE SOUTHERN CWFA.
CONFIDENCE IN SNOWFALL...MEDIUM/LOW.
CONFIDENCE IN TEMPS...HIGH.
TONIGHT THROUGH WEDNESDAY...
500MB HEIGHTS BEGIN TO RISE THIS EVENING WITH DIFFLUENT FLOW LIFTING
NORTH FROM THE SFC RIDGE CENTERED ACROSS THE OZARKS. THIS SHUD AID
IN ERODING SOME OF THE CLOUD COVER...AND COULD SEE P-CLOUDY SKIES
FOR A BRIEF PERIOD OVERNIGHT. THEN ANOTHER WEAK MID-LVL WAVE IS
PROGGED TO BUMP INTO THE DIFFLUENT FLOW AND BRING SOME MID-LVL
MOISTURE AND CLOUDS BACK TO THE AREA DURING THE OVERNIGHT HOURS.
500MB FLOW CONTINUES TO EVOLVE INTO A ZONAL SETUP...ALTHOUGH THIS
WILL ONLY BE TEMPORARY THRU WED. SFC RIDGE ACROSS THE OZARKS DRIFTS
EAST TOWARDS THE MID-ATLANTIC/GULF STATES...WITH LLVL FLOW TURNING
SOUTH/SOUTHWEST FOR THE CWFA.
FOR THE FIRST TIME IN SEVERAL DAYS WED MAY SEE THE 850MB 0 DEG
ISOTHERM LIFT OVERHEAD ALONG THE LEADING EDGE OF INCREASED WARM AIR
ADVECTION. THE MID-LVL THERMAL RIDGE CONTINUES TO WARM FURTHER SOUTH
WITH TEMPS RISING TO NEAR 9 DEG C OVER NORTHERN MISSOURI WED AFTN.
GIVEN THE EXPANSIVE SNOW COVER...THE CHALLENGE IS HOW WARM WILL WED
END UP BECOMING. GUIDANCE HAS TRENDED SLIGHTLY COOLER OVER THE PAST
FEW DAYS WITH WED HIGHS. AT THIS TIME THE GENERAL CONSENSUS HAS BEEN
ON TEMPS IN THE LOW 30S ALONG/NORTH OF I-80 AND POINTS SOUTH
POSSIBLY REACHING THE MID 30S.
WITH DEW POINTS PROGGED TO BE RISING TO ARND FREEZING...THE SNOWMELT
RATES WILL RAMP UP. WITH THE ADDED MOISTURE COUPLED WITH A
MOISTENING MID/UPR LVLS AHEAD OF THE NEXT WEATHER SYSTEM...THE
ENVIRONMENT SEEMS PRIMED FOR THE DEVELOPMENT OF PATCHY/AREAS OF FOG.
FREQUENTLY MELTING SNOW CAN PRODUCE SHALLOW DENSE FOG...SO THIS WILL
CONTINUE TO BE THE FOCUS WED NGT.
CONFIDENCE IN TEMPS...MEDIUM.
CONFIDENCE IN FOG DEVELOPING WED NGT...HIGH.
THURSDAY THROUGH SATURDAY...
MID-LVL FLOW CONTINUES TO PROGRESS INTO A SOUTHWEST SETUP WITH A
500MB VORT MAX PUSHING INTO THE FOUR-CORNERS REGION THUR. SFC
RIDGING IN THE LLVLS WILL BE PARKED OVER THE SOUTHEASTERN
CONUS...ALLOWING FOR CONTINUED FEED OF WARM AIR ADVECTING NORTH
THROUGH THE OZARKS INTO THE OHIO VALLEY/GREAT LAKES REGIONS THUR.
GUIDANCE CONTINUES TO FEATURE A WAVE DEVELOPING ALONG THE LEE-SIDE
OF THE ROCKIES THUR...AS A WEAK SFC RIDGE SAGS SOUTH FROM CENTRAL
CANADA INTO THE UPPER MIDWEST AND SHARPENS UP A BAROCLINIC ZONE OVER
THE NORTHERN PLAINS STRETCHING NORTHEAST THROUGH THE UPPER PENINSULA
OF MICHIGNA. THIS WILL LIKELY KEEP THE WARM AIR OVER THE CWFA
THUR...AND ANY PRECIP WILL LIKELY FALL AS LIQUID THUR. AT THE ONSET
THUR MORNING A BRIEF PERIOD OF FZDZ/FZRA MAY OCCUR...HOWEVER THIS
WILL LIKELY BE BRIEF. GUIDANCE HAS TRENDED SLIGHTLY FURTHER SOUTH
WITH THE SFC LOW FOR THUR NIGHT...AS THE 850MB LOW IS PROGGED TO
SLIDE OVER SOUTHCENTRAL WISC.
WITH SOME DEGREE OF UNCERTAINTY REMAINING IN THE PLACEMENT OF THE
SFC LOW...THIS OPENS UP DECREASED CONFIDENCE IN HIGH TEMPS FOR THUR.
A FURTHER NORTH PATH WOULD PROVIDE TEMPS IN THE MID/UPR
30S...MEANWHILE A CORRECTION TO THE SOUTH WOULD KEEP TEMPS ARND 30
TO LOW 30S. FURTHER COMPOUNDING THIS WOULD BE THE THEN POTENTIAL FOR
P-TYPE ISSUES.
THE SFC RIDGE ACROSS THE UPPER MIDWEST SHUD HELP TO PUSH THE
BAROCLINIC BOUNDARY SOUTH FOR FRI...AS THE LOW LIFTS NORTHEAST OF
THE FORECAST AREA. THIS SHUD AID IN COOLER AIR FILTERING IN BEHIND
AND PUSHING DEW POINTS BACK INTO THE 20S. P-TYPE FOR FRI SHUD BE
LIMITED TO RA/SN...AND TRANSITION TO ALL SN BY FRI AFTN/EVE.
500MB VORT MAX ACROSS THE FAR SOUTHWEST CONUS WILL BEGIN TO DIG
SOUTHEAST OF NEW MEXICO...WHICH WILL LIKELY TRANSLATE IN THE
DOWNSTREAM BOUNDARY SAGGING FURTHER SOUTH THROUGH THE OHIO VALLEY
FRI NGT. THEN YET ANOTHER WAVE IS PROGGED TO DEVELOP ACROSS EASTERN
TEXAS AND TAKE A CLASSIC TRAJECTORY TOWARDS THE OHIO VALLEY FOR THE
SECOND HALF OF THE WEEKEND.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
SUNDAY THROUGH EARLY CHRISTMAS WEEK...
ENSEMBLES INDICATE A SIMILAR COLD SETUP FOR THE SECOND HALF OF THE
WEEKEND INTO EARLY CHRISTMAS WEEK. WESTERN MID-LVL RIDGE MAY BEGIN
TO AMPLIFY FOR EARLY NEXT WEEK...RESULTING IN A DOWNSTREAM TROUGH
POSITIONED OVER THE GREAT LAKES REGION. OPERATIONAL SOLUTIONS
CONTINUE TO POINT TOWARDS A ROBUST WEATHER SYSTEM SUN LIFTING
NORTHEAST ACROSS THE REGION FROM THE SOUTHERN PLAINS/EASTERN
TEXAS...WITH TEMPS COLD ENOUGH TO SUPPORT ALL SNOW FOR THIS EVENT.
THEN ON THE BACKSIDE OF THIS MUCH COLDER AIR POURS BACK INTO THE
CWFA WITH TEMPS ALOFT RETURNING TO -10 TO -14 DEG C AT 850MB FOR
EARLY CHRISTMAS WEEK. THIS WILL KEEP SFC TEMPS IN THE UPPER TEENS TO
LOW 20S.
CONFIDENCE IN SUNDAY SYSTEM...HIGH.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* ISOLD SHSN THROUGH 16Z
* IFR CIGS CLEAR OUT LATER THIS MORNING
* GUSTY WEST WINDS DEVELOP LATER THIS MORNING AND CONTINUE INTO
THE AFTERNOON
IZZI
//DISCUSSION...UPDATED 14Z
RADAR TRENDS SHOW SNOW SHOWERS DRYING UP OVER THE AREA AND HAVE
CONSIDERABLY BACKED OFF ON SNOW MENTION IN THE TAFS. VSBY ALREADY
JUST BARELY ABOVE IFR...SO WOULDNT TAKE MUCH SNOW TO DROP VSBY TO
IFR BUT ACCUMS SHOULD JUST BE A DUSTING AT WORST. NORTH-SOUTH EDGE
TO IFR CIGS MAKING STEADY PROGRESS EAST AND SHOULD CLEAR OUT OF
ORD/MDW BY 17Z.
IZZI
UPDATED 12Z...
IFR CIGS HAVE SPREAD ACROSS THE TERMINALS AS THE LOW PRESSURE
TROUGH APPROACHES FROM THE WEST. THE MAIN LOW WILL PASS TO OUR
NORTH THROUGH ONTARIO TODAY...WITH ITS COLD FRONT SWINGING THROUGH
THIS AFTN. A BAND OF SNOW HAS FORMED OVER SOUTHERN WI AND
EXPECTING IT TO REACH RFD ARND 1230Z...THEN AT ORD BY 13Z. UNTIL
THEN...EXPECTING CONDITIONS TO STAY RIGHT WHERE THEY ARE. IFR
CIGS AND VFR/MVFR VSBY. WHEN THE SNOW ARRIVES...VSBYS WILL FALL
FURTHER TO AROUND A MILE. THERE SHOULD BE A BRIEF PERIOD OF
HEAVIER SNOW WITH VSBYS BELOW 1 MILE.
WINDS PICK UP AFTER THE COLD FRONT WITH GUSTS AROUND 30 KT. KEPT
MVFR CIGS GOING...BUT GUIDANCE SUGGESTS MVFR OR LOWER CIGS COULD
HANG AROUND LONGER THAN CURRENTLY FORECAST. BLOWING SNOW WILL
LIKELY BE AN ISSUE GIVEN THE FRESH LIGHT SNOW. NOT EXPECTING IT TO
IMPACT VSBY THOUGH.
HIGH PRESSURE PASSES TO THE SOUTH OVERNIGHT WITH WINDS BECOMING
SOUTHWEST AROUND 10 KT. WINDS TURN FURTHER SOUTH AND BEGIN GUSTING
TO AROUND 20 KT IN THE LATE MORNING...BUT EXPECTING VFR CONDITIONS.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM TO HIGH CONFIDENCE IN SNOW THIS MORNING
* MEDIUM CONFIDENCE ON EXACT TIMING OF IFR CIGS MOVING OUT THIS MORNING
* MEDIUM CONFIDENCE ON VFR CIGS THIS AFTERNOON
* HIGH CONFIDENCE IN REST OF FORECAST
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...IFR/LIFR CIGS PROBABLY DEVELOPING.
THURSDAY...IFR/LIFR LIKELY. CHANCE OF -RA/DZ.
FRIDAY...IFR LIKELY. CHANCE OF -RA/-SN.
SATURDAY...IFR POSSIBLE. CHANCE OF SNOW...MAINLY AT NIGHT.
SUNDAY...IFR POSSIBLE. CHANCE OF SNOW.
MONDAY...MVFR CIGS POSSIBLE.
IZZI
&&
.MARINE...
306 AM CST
FIRST OF ALL MADE NO CHANGES TO THE ONGOING HEADLINES AS THEY ALL
SEEM ON TRACK. A SMALL CRAFT ADVISORY WILL BE NEEDED FOR THE INDIANA
NEARSHORE WATERS AFTER THE GALE WARNING DUE TO LINGERING HAZARDOUS
WAVES.
LOW PRESSURE IS OVER ONTARIO AND IT WILL SLIDE TO THE EAST
TODAY...WHILE ITS COLD FRONT PASSES OVER THE LAKE THIS AFTERNOON.
AT THE SAME TIME HIGH PRESSURE BUILDS OVER THE CENTRAL PLAINS. THIS
WILL TIGHTEN THE PRESSURE GRADIENT OVER THE SOUTHERN END OF THE
LAKE...RESULTING IN LOW END GALES FORMING THIS MORNING THROUGH EARLY
THIS EVENING. WEST WINDS DIMINISH TO ARND 20 KT BY WEDNESDAY
MORNING AS HIGH PRESSURE PASSES TO THE SOUTH. WINDS PICK BACK UP ON
THE BACKSIDE OF THE HIGH LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING. A BRIEF PERIOD OF SW GALES TO 35 KT IS POSSIBLE DURING
THAT TIME. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED AS WELL FOR
WEDNESDAY AFTERNOON AND EVENING. WINDS WEAKEN WEDNESDAY NIGHT AS A
TROUGH OF LOW PRESSURE SITS OVER THE LAKE WEDNESDAY NIGHT THROUGH
THURSDAY. THE NEXT WEAK LOW MOVES OVER THE LAKE THURSDAY NIGHT
BEFORE SHIFTING EAST ON FRIDAY. WINDS TURN LIGHT AND VARIABLE
BEHIND THE LOW ON SATURDAY...BUT THEN TURN NORTH AND STRENGTHEN
SATURDAY NIGHT INTO SUNDAY IN RESPONSE TO THE NEXT SYSTEM. GUIDANCE
FEATURES ANOTHER LOW PUSHING UP THE OHIO RIVER VALLEY SATURDAY NIGHT
INTO SUNDAY WITH HIGH PRESSURE BUILDING DOWN THE PLAINS.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878 UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL
MIDNIGHT WEDNESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
557 AM CST TUE DEC 17 2013
.DISCUSSION...
328 AM CST
TODAY...
MAIN CONCERNS WILL BE FOCUSED ON THE MID-LVL WAVE THAT IS QUICKLY
SLIDING EAST ACROSS THE WESTERN GREAT LAKES...POSSIBLY BRINGING A
SLUG OF LGT SNOW TO NORTH/NORTHEAST IL AND NORTHWEST IN THIS MORNING
THRU MIDDAY. THEN THE POTENTIAL FOR SOME BLOWING SNOW AS THE
GRADIENT RAMPS UP MIDDAY AND MIXING JUMPS TO ARND 3KFT AGL.
IR IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS THE REGION...AND
SOME COOLING WITH CLOUD TOPS WITH THE WEAK WAVE SLIDING EAST ACROSS
WESTCENTRAL WISC EARLY THIS MORNING. KARX RADAR INDICATES AN AREA OF
RETURNS ACROSS THIS AREA...HOWEVER THE RECENT COUPLE OF HOURS HAVE
INDICATED SOME DOWNWARD TREND IN THE SOUTHERN PORTION OF THIS
PRECIP. SFC OBS ARE NOT INDICATING ANY SNOW IN FAR SOUTHEAST MN AND
HAS TENDED TO BE FOCUSED FURTHER NORTH. BASED ON CURRENT
TRAJECTORY...THE BEST LGT SNOW MAY END UP HOLDING FURTHER NORTH INTO
WISC. BUFR PROFILES HAVE BACKED OFF ON THE OMEGA PLACEMENT...HOWEVER
A HANDFUL OF POINTS CONTINUE TO INDICATE SOME DEGREE OF LIFT THROUGH
THE FAVORED DGZ ARND 12-15Z. DPROG/DT OF THE BUFR SITES ALSO
INDICATES A DOWNWARD TREND...SUPPORTING THE LOWER CONFIDENCE IN SNOW
TOTALS. THE CAVEAT AND CHALLENGE IS THE NARROW CHANNEL OF MOISTURE
THAT STRETCHES WEST AND RECENT RAP GUIDANCE HAS INDICATED AN
ENHANCEMENT TO THIS FEATURE AS IT PIVOTS EAST ACROSS THE CWFA THIS
MORNING.
SNOWFALL RATIOS SHOULD FALL AROUND 20:1...SO RATHER DRY.
BASED ON COBB OUTPUT FROM THESE PROFILES SNOWFALL SHUD GENERALLY
FALL BETWEEN A FEW TENTHS TO 1". COULD SEE AREAS CLOSEST TO THE
WISCONSIN STATELINE PICKING UP SLIGHTLY MORE OR WITHIN A 1-2" RANGE.
THE WAVE WILL REMAIN PROGRESSIVE AND SHUD COME TO AN END BY 15-17Z
FROM WEST TO EAST...AS WIND GUSTS BEGIN TO DEVELOP. ANY FRESH
SNOWFALL SHUD EASILY BLOW AROUND. THIS MAY BE MORE FOCUSED ACROSS
AREAS NORTH OF I-80...AS THE PATCHY DZ EARLY THIS MORNING WILL
MOISTEN UP THE SNOW FURTHER SOUTH AND LIMIT THE ABILITY FOR THE SNOW
TO BLOW AROUND.
TEMPS WILL BEGIN TO REBOUND TDY...AS THE 500MB TROUGH AXIS BEGINS TO
PUSH EAST OF THE WESTERN GREAT LAKES. TEMPS WILL STEADILY WARM INTO
THE UPR 20S TO ARND 30 ACROSS THE SOUTHERN CWFA.
CONFIDENCE IN SNOWFALL...MEDIUM/LOW.
CONFIDENCE IN TEMPS...HIGH.
TONIGHT THROUGH WEDNESDAY...
500MB HEIGHTS BEGIN TO RISE THIS EVENING WITH DIFFLUENT FLOW LIFTING
NORTH FROM THE SFC RIDGE CENTERED ACROSS THE OZARKS. THIS SHUD AID
IN ERODING SOME OF THE CLOUD COVER...AND COULD SEE P-CLOUDY SKIES
FOR A BRIEF PERIOD OVERNIGHT. THEN ANOTHER WEAK MID-LVL WAVE IS
PROGGED TO BUMP INTO THE DIFFLUENT FLOW AND BRING SOME MID-LVL
MOISTURE AND CLOUDS BACK TO THE AREA DURING THE OVERNIGHT HOURS.
500MB FLOW CONTINUES TO EVOLVE INTO A ZONAL SETUP...ALTHOUGH THIS
WILL ONLY BE TEMPORARY THRU WED. SFC RIDGE ACROSS THE OZARKS DRIFTS
EAST TOWARDS THE MID-ATLANTIC/GULF STATES...WITH LLVL FLOW TURNING
SOUTH/SOUTHWEST FOR THE CWFA.
FOR THE FIRST TIME IN SEVERAL DAYS WED MAY SEE THE 850MB 0 DEG
ISOTHERM LIFT OVERHEAD ALONG THE LEADING EDGE OF INCREASED WARM AIR
ADVECTION. THE MID-LVL THERMAL RIDGE CONTINUES TO WARM FURTHER SOUTH
WITH TEMPS RISING TO NEAR 9 DEG C OVER NORTHERN MISSOURI WED AFTN.
GIVEN THE EXPANSIVE SNOW COVER...THE CHALLENGE IS HOW WARM WILL WED
END UP BECOMING. GUIDANCE HAS TRENDED SLIGHTLY COOLER OVER THE PAST
FEW DAYS WITH WED HIGHS. AT THIS TIME THE GENERAL CONSENSUS HAS BEEN
ON TEMPS IN THE LOW 30S ALONG/NORTH OF I-80 AND POINTS SOUTH
POSSIBLY REACHING THE MID 30S.
WITH DEW POINTS PROGGED TO BE RISING TO ARND FREEZING...THE SNOWMELT
RATES WILL RAMP UP. WITH THE ADDED MOISTURE COUPLED WITH A
MOISTENING MID/UPR LVLS AHEAD OF THE NEXT WEATHER SYSTEM...THE
ENVIRONMENT SEEMS PRIMED FOR THE DEVELOPMENT OF PATCHY/AREAS OF FOG.
FREQUENTLY MELTING SNOW CAN PRODUCE SHALLOW DENSE FOG...SO THIS WILL
CONTINUE TO BE THE FOCUS WED NGT.
CONFIDENCE IN TEMPS...MEDIUM.
CONFIDENCE IN FOG DEVELOPING WED NGT...HIGH.
THURSDAY THROUGH SATURDAY...
MID-LVL FLOW CONTINUES TO PROGRESS INTO A SOUTHWEST SETUP WITH A
500MB VORT MAX PUSHING INTO THE FOUR-CORNERS REGION THUR. SFC
RIDGING IN THE LLVLS WILL BE PARKED OVER THE SOUTHEASTERN
CONUS...ALLOWING FOR CONTINUED FEED OF WARM AIR ADVECTING NORTH
THROUGH THE OZARKS INTO THE OHIO VALLEY/GREAT LAKES REGIONS THUR.
GUIDANCE CONTINUES TO FEATURE A WAVE DEVELOPING ALONG THE LEE-SIDE
OF THE ROCKIES THUR...AS A WEAK SFC RIDGE SAGS SOUTH FROM CENTRAL
CANADA INTO THE UPPER MIDWEST AND SHARPENS UP A BAROCLINIC ZONE OVER
THE NORTHERN PLAINS STRETCHING NORTHEAST THROUGH THE UPPER PENINSULA
OF MICHIGNA. THIS WILL LIKELY KEEP THE WARM AIR OVER THE CWFA
THUR...AND ANY PRECIP WILL LIKELY FALL AS LIQUID THUR. AT THE ONSET
THUR MORNING A BRIEF PERIOD OF FZDZ/FZRA MAY OCCUR...HOWEVER THIS
WILL LIKELY BE BRIEF. GUIDANCE HAS TRENDED SLIGHTLY FURTHER SOUTH
WITH THE SFC LOW FOR THUR NIGHT...AS THE 850MB LOW IS PROGGED TO
SLIDE OVER SOUTHCENTRAL WISC.
WITH SOME DEGREE OF UNCERTAINTY REMAINING IN THE PLACEMENT OF THE
SFC LOW...THIS OPENS UP DECREASED CONFIDENCE IN HIGH TEMPS FOR THUR.
A FURTHER NORTH PATH WOULD PROVIDE TEMPS IN THE MID/UPR
30S...MEANWHILE A CORRECTION TO THE SOUTH WOULD KEEP TEMPS ARND 30
TO LOW 30S. FURTHER COMPOUNDING THIS WOULD BE THE THEN POTENTIAL FOR
P-TYPE ISSUES.
THE SFC RIDGE ACROSS THE UPPER MIDWEST SHUD HELP TO PUSH THE
BAROCLINIC BOUNDARY SOUTH FOR FRI...AS THE LOW LIFTS NORTHEAST OF
THE FORECAST AREA. THIS SHUD AID IN COOLER AIR FILTERING IN BEHIND
AND PUSHING DEW POINTS BACK INTO THE 20S. P-TYPE FOR FRI SHUD BE
LIMITED TO RA/SN...AND TRANSITION TO ALL SN BY FRI AFTN/EVE.
500MB VORT MAX ACROSS THE FAR SOUTHWEST CONUS WILL BEGIN TO DIG
SOUTHEAST OF NEW MEXICO...WHICH WILL LIKELY TRANSLATE IN THE
DOWNSTREAM BOUNDARY SAGGING FURTHER SOUTH THROUGH THE OHIO VALLEY
FRI NGT. THEN YET ANOTHER WAVE IS PROGGED TO DEVELOP ACROSS EASTERN
TEXAS AND TAKE A CLASSIC TRAJECTORY TOWARDS THE OHIO VALLEY FOR THE
SECOND HALF OF THE WEEKEND.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
SUNDAY THROUGH EARLY CHRISTMAS WEEK...
ENSEMBLES INDICATE A SIMILAR COLD SETUP FOR THE SECOND HALF OF THE
WEEKEND INTO EARLY CHRISTMAS WEEK. WESTERN MID-LVL RIDGE MAY BEGIN
TO AMPLIFY FOR EARLY NEXT WEEK...RESULTING IN A DOWNSTREAM TROUGH
POSITIONED OVER THE GREAT LAKES REGION. OPERATIONAL SOLUTIONS
CONTINUE TO POINT TOWARDS A ROBUST WEATHER SYSTEM SUN LIFTING
NORTHEAST ACROSS THE REGION FROM THE SOUTHERN PLAINS/EASTERN
TEXAS...WITH TEMPS COLD ENOUGH TO SUPPORT ALL SNOW FOR THIS EVENT.
THEN ON THE BACKSIDE OF THIS MUCH COLDER AIR POURS BACK INTO THE
CWFA WITH TEMPS ALOFT RETURNING TO -10 TO -14 DEG C AT 850MB FOR
EARLY CHRISTMAS WEEK. THIS WILL KEEP SFC TEMPS IN THE UPPER TEENS TO
LOW 20S.
CONFIDENCE IN SUNDAY SYSTEM...HIGH.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* IFR CIGS WITH LOW END VFR VSBY THIS MORNING. IFR CIGS PERSIST
THROUGH THE SNOWFALL.
* SNOW RETURNS ARND 13Z WITH VSBY DROPPING TO AROUND A MILE. BRIEF
REDUCTIONS TO BELOW 1 SM AND 500 FT CIGS AFTER 14Z.
* STRONG WEST WINDS SET UP LATE IN THE MORNING THROUGH THE
AFTN...20 KT GUSTING TO ARND 30 KT.
* GUSTY SOUTH WINDS EXPECTED TOMORROW AFTERNOON.
JEE
//DISCUSSION...UPDATED 12Z...
IFR CIGS HAVE SPREAD ACROSS THE TERMINALS AS THE LOW PRESSURE
TROUGH APPROACHES FROM THE WEST. THE MAIN LOW WILL PASS TO OUR
NORTH THROUGH ONTARIO TODAY...WITH ITS COLD FRONT SWINGING THROUGH
THIS AFTN. A BAND OF SNOW HAS FORMED OVER SOUTHERN WI AND
EXPECTING IT TO REACH RFD ARND 1230Z...THEN AT ORD BY 13Z. UNTIL
THEN...EXPECTING CONDITIONS TO STAY RIGHT WHERE THEY ARE. IFR
CIGS AND VFR/MVFR VSBY. WHEN THE SNOW ARRIVES...VSBYS WILL FALL
FURTHER TO AROUND A MILE. THERE SHOULD BE A BRIEF PERIOD OF
HEAVIER SNOW WITH VSBYS BELOW 1 MILE.
WINDS PICK UP AFTER THE COLD FRONT WITH GUSTS AROUND 30 KT. KEPT
MVFR CIGS GOING...BUT GUIDANCE SUGGESTS MVFR OR LOWER CIGS COULD
HANG AROUND LONGER THAN CURRENTLY FORECAST. BLOWING SNOW WILL
LIKELY BE AN ISSUE GIVEN THE FRESH LIGHT SNOW. NOT EXPECTING IT TO
IMPACT VSBY THOUGH.
HIGH PRESSURE PASSES TO THE SOUTH OVERNIGHT WITH WINDS BECOMING
SOUTHWEST AROUND 10 KT. WINDS TURN FURTHER SOUTH AND BEGIN GUSTING
TO AROUND 20 KT IN THE LATE MORNING...BUT EXPECTING VFR CONDITIONS.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN FORECAST THROUGH 16Z.
* MEDIUM CONFIDENCE IN HOW QUICKLY CIGS WILL LIFT BEHIND THE SNOW.
* MEDIUM CONFIDENCE THAT BLOWING SNOW WILL NOT IMPACT VSBYS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR OR LOWER CIGS/VSBY PSBL.
THURSDAY...RAIN AND FOG. MVFR OR LOWER.
FRIDAY...CHC RAIN OR SNOW BECOMING ALL SNOW BY THE AFTN. MVFR OR
LOWER.
SATURDAY...SNOW. MVFR OR LOWER.
SUNDAY...SNOW DURING THE DAY. MVFR PSBL.
MONDAY...VFR.
JEE
&&
.MARINE...
306 AM CST
FIRST OF ALL MADE NO CHANGES TO THE ONGOING HEADLINES AS THEY ALL
SEEM ON TRACK. A SMALL CRAFT ADVISORY WILL BE NEEDED FOR THE INDIANA
NEARSHORE WATERS AFTER THE GALE WARNING DUE TO LINGERING HAZARDOUS
WAVES.
LOW PRESSURE IS OVER ONTARIO AND IT WILL SLIDE TO THE EAST
TODAY...WHILE ITS COLD FRONT PASSES OVER THE LAKE THIS AFTERNOON.
AT THE SAME TIME HIGH PRESSURE BUILDS OVER THE CENTRAL PLAINS. THIS
WILL TIGHTEN THE PRESSURE GRADIENT OVER THE SOUTHERN END OF THE
LAKE...RESULTING IN LOW END GALES FORMING THIS MORNING THROUGH EARLY
THIS EVENING. WEST WINDS DIMINISH TO ARND 20 KT BY WEDNESDAY
MORNING AS HIGH PRESSURE PASSES TO THE SOUTH. WINDS PICK BACK UP ON
THE BACKSIDE OF THE HIGH LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING. A BRIEF PERIOD OF SW GALES TO 35 KT IS POSSIBLE DURING
THAT TIME. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED AS WELL FOR
WEDNESDAY AFTERNOON AND EVENING. WINDS WEAKEN WEDNESDAY NIGHT AS A
TROUGH OF LOW PRESSURE SITS OVER THE LAKE WEDNESDAY NIGHT THROUGH
THURSDAY. THE NEXT WEAK LOW MOVES OVER THE LAKE THURSDAY NIGHT
BEFORE SHIFTING EAST ON FRIDAY. WINDS TURN LIGHT AND VARIABLE
BEHIND THE LOW ON SATURDAY...BUT THEN TURN NORTH AND STRENGTHEN
SATURDAY NIGHT INTO SUNDAY IN RESPONSE TO THE NEXT SYSTEM. GUIDANCE
FEATURES ANOTHER LOW PUSHING UP THE OHIO RIVER VALLEY SATURDAY NIGHT
INTO SUNDAY WITH HIGH PRESSURE BUILDING DOWN THE PLAINS.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM TUESDAY TO 9 PM TUESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...9 AM
TUESDAY TO MIDNIGHT WEDNESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS GAYLORD MI
1038 AM EST TUE DEC 17 2013
.SYNOPSIS...
ISSUED AT 433 AM EST TUE DEC 17 2013
LIGHT ACCUMULATIONS ARE EXPECTED OVER NORTHWEST LOWER AND NORTHERN
CHIPPEWA COUNTY...WHERE LAKE EFFECT SNOW WILL CONTINUE THROUGH THE
DAY AND THEN INTENSIFY LATE THIS EVENING PROVIDING POSSIBLY LOCALLY
MODERATE SNOWFALL ACCUMULATIONS. CONTINUED BOUTS OF OCCASIONAL SNOW
ARE EXPECTED OVER THE NEXT COUPLE OF DAYS...AS MULTIPLE SYSTEMS PASS
THROUGH THE AREA. AFTER TODAY...WE WILL SEE SOMEWHAT MILDER
TEMPERATURES IN THE REGION.
&&
.UPDATE...
ISSUED AT 1015 AM EST TUE DEC 17 2013
BAND OF SNOW IS MOVING SOUTH OF M-72 AND ALONG THE M-55 CORRIDOR.
SNOW HAS STRUGGLED TO GET MUCH NORTH OF THIS AREA. ONCE THE
INITIAL BAND IS THROUGH, THE SNOW SHOWERS BECOME SCATTERED, WITH
THE BACK EDGE ALONG A SECONDARY TROUGH (15Z RUC ANALYSIS). SO WILL
TWEAK THE POP GRIDS A BIT TO ACCOUNT FOR THE SNOW TRACK AND THE
BACK END OF THIS SYSTEM. THIS WOULD SEEMINGLY LEAVE MOST IF NOT
ALL OF THE M-32 CORRIDOR AND NORTH OUT OF THE SNOW THIS MORNING,
AND PROBABLY PART OF THE EARLY AFTERNOON. THERE IS VERY LITTLE
GOING ON IN LAKE SUPERIOR SO WILL KEEP THE CHANCE POPS FOR THE
TIME BEING.
UPDATE ISSUED AT 649 AM EST TUE DEC 17 2013
BACK EDGE OF SYSTEM SNOWS EXITING NE LOWER BEHIND DEPARTING
SHORTWAVE. SUBSIDENCE AND DRYING FROM ALOFT IN ITS WAKE WITH SOME
REAL LOW CLOUDS SWEPT IN OVER MOST OF THE AREA. NEXT SHORTWAVE
ALREADY ABOUT TO EXERT ITSELF ON THE GTV BAY REGION
SOUTHWARD....WITH LIGHT SNOWS MOVING IN OVER THE NEXT FEW HOURS.
THERE IS ALSO A NARROW CORRIDOR OF MODERATE SNOWS SET TO AFFECT
AREAS CLOSER TO THE FRANKFORT...MANISTEE AND CADILLAC AREAS.
INCREASED CHANCES FOR SEEING SNOW THERE...AND ALSO BUMPED UP SNOW
AMOUNTS TO UP TO 2 INCHES. NOT OUT OF THE QUESTION TO SEE LOCALLY
HIGHER AMOUNTS AS THE CORRIDOR OF MODERATE SNOWS MAY TRAIN FOR A
COUPLE OF HOURS. THIS IS WORTH KEEPING A CLOSE EYE ON FOR A
POSSIBLE SNEAKIER HIGHER SNOWFALL.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 433 AM EST TUE DEC 17 2013
IT SIMPLY DOESN`T STOP...AND THAT`S A GOOD THING FOR THE SNOW FAN
THAT I AM! BUT...LAKE PROCESSES THAT ARE ON PERPETUAL OVERDRIVE SURE
MAKES FOR SOME CHALLENGING FORECAST SHIFTS. THIS ONE IS NO DIFFERENT
(WHY WOULD IT BE?)...WITH A FULL-FLEDGED SOUTHWEST FLOW EVENT
IMPACTING EASTERN UPPER AS IF THIS TYPING...NO DOUBT HELPED ALONG BY
PASSING SHORTWAVE TROUGH/ALBERTA CLIPPER TYPE SYSTEM. SYSTEM ITSELF
HAS A TOUCH OF SNOW WITH IT...BRINGING SOME LIGHT ACCUMULATIONS TO
MOST. PATTERN REMAINS IN RAPID-FIRE MODE...WITH NEXT SHORTWAVE AND
POCKET OF UPWARD QG SUPPORT ALREADY RACING EAST INTO WESTERN
WISCONSIN. PLETHORA OF FORECAST CHALLENGES GIVEN THIS ENERGETIC...
LAKE ENHANCED RICH PATTERN...WITH MAIN EMPHASIS CENTERED ONCE AGAIN
ON ADDITIONAL SNOW AMOUNTS AND ASSOCIATED HEADLINE CONCERNS.
OVERHEAD WAVE LOOKS TO EXIT QUICKLY EARLY THIS MORNING...WITH
SUBSIDENCE AND MID LEVEL DRYING KICKING IN BEHIND IT. WIDESPREAD
SNOWS WILL FOLLOW SUITE...ENDING FROM WEST TO EAST WITHIN THE NEXT
FEW HOURS. MAIN CONCERN REMAINS IMPRESSIVE...BUT INCREASING TRANSIENT
...SOUTHWEST FLOW BAND EXTENDING FROM LEELANAU COUNTY UP
INTO THE STRAITS. WINDS ALREADY VEERING CONSIDERABLY OVER THE
WESTERN HALF OF THE BIG POND...AND SIMPLE EXTRAPOLATION WOULD
SUGGEST THIS WIND SHIFT LINE PROPELLING THE BAND INLAND QUICKLY
SHORTLY AFTER ISSUANCE OF THIS FORECAST PACKAGE. NO DOUBT A BURST OF
VERY HEAVY SNOW WILL ACCOMPANY THIS BAND...LIKELY IN EXCESS OF ONE
INCH PER HOUR. HOWEVER...THIS LOOKS TO BE A SHORT-LIVED EVENT FROM
THIS POINT ON...AND WILL SIMPLY CANCEL ALL INHERITED ADVISORIES.
NEXT LOW AMPLITUDE WAVE APPROACHES QUICKLY THIS MORNING...WITH MAIN
CORE OF DYNAMICS SPREADING BY TO OUR SOUTH. BEST CHANCE FOR
ATTENDANT LIGHT SNOW EXPECTED ACROSS THE SOUTH THIRD OF THE AREA.
LAKE SUPPORT BY THIS TIME LOOK NEGLIGIBLE AS H8 TEMPERATURES "WARM"
TO AROUND -8C BY SUNRISE. THUS...NOT EXPECTING A WHOLE LOT OF
ADDITIONAL ACCUMULATION TODAY...LIKELY JUST AROUND AN INCH OR SO
FROM CADILLAC AND POINTS WEST. MORE SCATTERED AND LIGHTER SNOW
SHOWERS EXPECTED ELSEWHERE TODAY WITH MINIMAL ACCUMULATIONS. MIGHT
ACTUALLY FEEL KINDA BALMY AS HIGHS REACH INTO THE MIDDLE...AND
PERHAPS...UPPER 20S.
LAKE CONCERNS RAMP UP ONCE AGAIN TONIGHT AS WINDS SWING AROUND
WEST/NORTHWESTERLY AND NEXT SLUG OF COLDER AIR DROPS INTO THE
NORTHERN LAKES. HOWEVER...UNLIKE RECENT ARCTIC PLUNGES...THIS ONE IS
NOT QUITE AS COLD...WITH H8 TEMPERATURES ONLY FALLING INTO THE
NEGATIVE MID TEENS BY MORNING. BACKGROUND SYNOPTIC MOISTURE NOT TOO
SHABBY AT ALL...WITH GOOD MOISTURE THROUGH RESPECTABLE 750MB CBL
HEIGHT. WHILE STRONGEST OMEGA IS PEGGED JUST SHORT OF THE DGZ...AT
LEAST SOME LIFT IS NOTED IN THE BOTTOM END OF THIS ZONE. LACK OF
WELL-DEFINED LOW LEVEL CONVERGENCE AXES AND SOMEWHAT MORE MARGINAL
PARAMETERS LISTED ABOVE SHOULD KEEP THIS FROM BECOMING TOO BIG OF AN
EVENT. HAVE TENTATIVELY PAINTED IN 2 TO 4 INCHES IN THE TRADITIONAL
LAKE SNOW BELTS OF BOTH PENINSULAS BY MORNING. DEFINITELY NOT OUT OF
THE REALM OF POSSIBILITY FOR LOCALLY HIGHER AMOUNTS AND HEADLINES.
WILL PUNT THIS DECISION TO THE DAY CREW...LEAVING TIME TO MORE
THOROUGHLY ACCESS INCOMING AIRMASS VIA 12Z RAOBS. LOWS TONIGHT BACK
DOWN INTO THE TEENS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 433 AM EST TUE DEC 17 2013
NRN MICHIGAN WILL BE UNDERWAY INTO A LESS COLD PATTERN WITH
TEMPERATURES RETURNING TO MORE NEAR NORMAL LEVELS...AS DEEPER UPPER
TROUGHING IS REPLACED BY A FASTER MORE ZONAL FLOW ALOFT. UPSTREAM
TROUGHING WILL HOWEVER SEND SOME ENERGY INTO THE GREAT LAKES
WEDNESDAY...BEFORE CUTTING OFF ACROSS THE WESTERN CONUS. GETS A TAD
MORE ACTIVE THURSDAY NIGHT AND OVER THE WEEKEND WITH CUTOFF LOW
DIGGING INTO THE FAR SRN ROCKIES...AND OVERALL UPPER AIR PATTERN
BECOMING MORE AMPLIFIED BY THE COMING WEEKEND. THERE IS AN EXPECTED
TAP OF DEEPER GULF MOISTURE WITH TIME...WITH BOTH JETS USHERING IN
SHORTWAVE ENERGY...NOT PHASING PER SE...BUT CERTAINLY THE CHANCE FOR
A SIGNIFICANT STORM SYSTEM IN THE EASTERN PART OF THE COUNTRY...WITH
AN ASSOCIATED CORRIDOR OF HEAVIER SNOW SOMEWHERE ACROSS OUR NECK OF
THE WOODS.
WEDNESDAY THROUGH THURSDAY...A RELATIVELY QUIET PERIOD OF WEATHER
WITH THE COLD UPPER TROUGH EXITING EAST AND FLOW GOING RATHER ZONAL.
A KINK/SHORTWAVE IN THE WNW FLOW ALOFT OVER ONTARIO WILL DAMPEN AS
IT CROSSES TO OUR NORTH...INDUCING A WEAK SFC LOW/CLIPPER. THIS
CLIPPER WILL BE LOSING STRENGTH AS IT LIFTS A WARM FRONT AND BAND OF
DEEPER MOISTURE THROUGH NRN MICHIGAN WEDNESDAY AND WEDNESDAY
EVENING. LIKELY SOME SCATTERED LIGHT LAKE EFFECT SNOW SHOWERS IN
WESTERLY FLOW REGIMES...AT LEAST IN THE MORNING WITH MINIMAL
ACCUMULATIONS UNDER AN INCH. LOW LEVEL FLOW AHEAD OF THE CLIPPER
WILL BRING WARMER LOW LEVEL TEMPERATURES TO EVENTUALLY SHUT OFF ANY
LES. SNOW CHANCES FROM THE SYSTEM ITSELF IS RATHER MINIMAL AS WELL
WITH AN INITIAL DRY LAYER H8-H7 LAYER GETTING SATURATED BRIEFLY
ALONG WITH THE UPPER LEVELS FOR A WINDOW OF OPPORTUNITY FOR A NARROW
CORRIDOR OF LIGHT SNOW TO PUSH ON THROUGH. WILL JUST HAVE SOME
SMALLISH CHANCES FOR NOW. A FAIRLY WEAK COLD FRONT DROPS IN OVER US
WEDNESDAY NIGHT INTO THURSDAY...BEFORE LAYING OUT ACROSS LOWER
MICHIGAN. WITH AN INCREASING LIGHT AND MORE VARIABLE FLOW DEVELOPING
AND SHALLOW SUB H8 MOISTURE IN THE MIX...A GOOD BET FOR SOME STRATUS
ISSUES. ACROSS THE EASTERN UP...MAYBE SOME LIGHT SNOW/FLURRIES IN
COLDEST AIR OFF LAKE SUPERIOR...BUT IT`S FAIRLY DRY. EXACT PLACEMENT
OF THE FRONT AND STRATUS HAS SOME UNCERTAINTY...BUT STILL NOT MUCH
EXPECTED FROM A SENSIBLE WEATHER STANDPOINT. WILL SEE SOME INCREASED
CLOUDS DEVELOPING LATER THURSDAY...AS INITIAL SRN STREAM ENERGY AND
NEXT NRN STREAM WEAK WAVE DROP IN TOWARD THE WESTERN GREAT LAKES.
THURSDAY NIGHT THROUGH SATURDAY...THAT FRONT WILL NOT BE
FORGOTTEN...AND IT`S PLACEMENT WILL BE IMPORTANT FOR THE THURSDAY
NIGHT AND EARLY FRIDAY TIME PERIOD. THE AFOREMENTIONED ENERGY FROM
BOTH STREAMS ARRIVE...AND TRY TO WORK WITH GULF MOISTURE TRYING TO
LIFT INTO THE LOWER AND MIDDLE MISSISSIPPI VALLEY. CLOUDS AND
PRECIPITATION ARE EXPECTED TO DEVELOP WITH DEEP MOISTURE SATURATING
THE COLUMN AS WEAK LOW PRESSURE DEVELOPS AND LIFTS NORTHEAST ALONG
THE LAID OUT FRONT. THERMAL PROFILES LOOK TO BE FOR AN ALL SNOW TYPE
EVENT FOR US...WITH AN OUTSIDE CHANCE THAT WE COULD SEE SOME RAIN
MIX IN ALONG THE M-55 CORRIDOR. THIS ALSO WHERE THE BEST CHANCES FOR
PRECIPITATION WILL RESIDE...BUT NRN STREAM WAVE WILL STILL PRESENT
ALL OF NRN MICHIGAN WITH A LIKELY SHOT OF LIGHT SNOW THROUGH FRIDAY
MORNING. AGAIN...WHERE THE FRONT WAS...AND WHETHER OR NOT IT SHIFTS
SOUTH...ARE KEY IN WHETHER OR NOT WE CAN GET SOME COLD ENOUGH AIR IN
HERE FOR SOME LIGHT LES SNOW SHOWERS...AND THERE IS QUITE A BIT OF
UNCERTAINTY THERE. EITHER WAY...EVEN WITH ANOTHER WEAK NRN STREAM
WAVE FRIDAY NIGHT INTO SATURDAY...ANY PRECIPITATION WE GET LOOKS TO
BE MINIMAL. ALL CONSIDERED...WILL NOT BE SURPRISED AT ALL...IF THERE
ISN`T SOME SORT OF LIGHT SNOW FLOATING AROUND.
SATURDAY NIGHT THROUGH MONDAY...POTENTIAL STORM? SRN STREAM CUTOFF
EXPECTED TO GET LIFTED INTO THE UPPER TROUGH...BUT NOT TOTALLY PHASE
TOGETHER. HOWEVER...A DEEP GULF OF MOISTURE TAP LIFTS NORTHWARD
AHEAD OF THE SRN STREAM WAVE...AND GET FORCED ALONG THE SFC FRONT
WHICH IS EXPECTED ALONG AND NORTH OF THE OHIO RIVER VALLEY....MAYBE
AS FAR NORTH AS SE LOWER MICHIGAN. A TIGHT BAROCLINIC ZONE DEVELOPS
AS LOW PRESSURE LIFTS TOWARD THE EASTERN GREAT LAKES. A CORRIDOR OF
HEAVY PRECIPITATION IS POSSIBLE ALONG THE FRONT...WITH THE NRN FRINGE
INTO COLD ENOUGH AIR FOR WHAT COULD WIND UP BEING AN AXIS OF HEAVIER
SNOWFALL FOR SOMEWHERE IN LOWER MICHIGAN. RIGHT NOW...MAYBE OUR FAR
SE COUNTIES SEEING SOME OF THIS ACTION??? REMAINS TO BE SEEN...AS
TIME DRAWS NEARER. NOT ENOUGH CONFIDENCE JUST YET FOR ANY MENTION
IN THE OUTLOOK SECTION OF THE HWOAPX.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 629 AM EST TUE DEC 17 2013
IFR/LOW MVFR CIGS HAS SWEPT IN OVER MUCH OF THE AREA...WITH APN
ABOUT TO SEE CIGS COME DOWN. THIS IN SUBSIDENCE REGION BEHIND
DEPARTING DISTURBANCE ALOFT. MVFR TO BE THE PREVAILING CIG THROUGH
TONIGHT WITH MINIMAL MIXING IN LIGHTENING LOW LEVEL WINDS AS WEAK
LOW PRESSURE APPROACHES THROUGH THE DAY. ALREADY SEEING ADDITIONAL
LIGHT SNOWS WORKING INTO MBL...AND SOON TVC. COULD BE A 1-2 HR
PERIOD OF MORE MODERATE SNOWFALL NEAR MBL PER UPSTREAM RADAR AND
OBSERVATIONS...RESULTING IN 1/2SM SN AND IFR CONDITIONS. COLD
FRONT CROSSES LATE TODAY AND TONIGHT WITH INCREASING LES COVERAGE
AND INTENSITIES (MAINLY TONIGHT) FOR WNW FLOW AREAS THAT HIT
MAINLY BETWEEN PLN/TVC. REGARDLESS...EXPECT AT LEAST PERIODS OF
LAKE EFFECT SNOWS.
&&
.MARINE...
ISSUED AT 433 AM EST TUE DEC 17 2013
WEST/SOUTHWEST WINDS WILL SLOWLY VEER MORE WESTERLY...AND
EVENTUALLY NORTHWESTERLY TODAY INTO THIS EVENING. STRONGEST CORE
OF WINDS EXPECTED ACROSS NORTHERN LAKE MICHIGAN...WHERE SCA
CONDITIONS WILL CONTINUE RIGHT THROUGH TONIGHT. WINDS WILL QUICKLY
BACK SOUTHWESTERLY ONCE AGAIN WEDNESDAY WELL AHEAD OF NEXT
DEVELOPING LOW PRESSURE SYSTEM.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST WEDNESDAY FOR LMZ344>346.
LS...NONE.
&&
$$
UPDATE...JL
SYNOPSIS...TL
SHORT TERM...MB
LONG TERM...SD
AVIATION...SD
MARINE...MB
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
520 AM CST TUE DEC 17 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST TUE DEC 17 2013
THE THERMAL RIDGE WEAKENED A BIT WITH THE PASSAGE OF A WEAK COLD
FRONT TONIGHT. AS A RESULT...HIGH PRESSURE IS BUILDING THROUGH THE
NRN AND CNTL HIGH PLAINS ALLOWING FOR RADIATIONAL COOLING IN MOST
VALLEYS. THE RUC SHOWS LOW PRESSURE REFORMING ACROSS THE HIGH
PLAINS TODAY AND THIS SHOULD LIFT A WARM FRONT PART WAY THROUGH
THE FCST AREA. THE WARM FRONT WOULD LIKELY REACH HIGHWAY 183 BY
LATE AFTN.
FCST HIGHS FOLLOW THE WARMEST MODEL...THE HRRR FOR HIGHS NEAR 60
ACROSS THE SOUTHWEST WHERE THE THERMAL RIDGE WILL BE IN PLACE ALL
DAY. JUST SCATTERED HIGH CLOUDS ARE EXPECTED AS A SOLID BANK OF
CIRRUS IS OVER BRITISH COLUMBIA THIS AM.
THE RAP MODEL SHOWS WEST WINDS AT H850MB AT 15 TO 30KT AND THE MODEL
CONSENSUS 500M AGL WINDS ARE WEST AND SOUTHWEST AT 10 TO 20KT WHICH
WOULD PRODUCE 10 TO 20 MPH WINDS AT THE SFC.
LOWS TONIGHT VARY WIDELY WITH TEENS IN VALLEYS TO NEAR 30 ACROSS THE
SANDHILLS. A SHALLOW INVERSION SHOULD FORM GIVEN THE LIMITED HIGH
CLOUD COVER EXPECTED AND WESTERLY H850MB WINDS OF 20 TO 40KT. H850MB
TEMPS RISE IN THE TEENS ACROSS WRN NEB.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 355 AM CST TUE DEC 17 2013
PRIMARY CONCERNS FOR THIS FORECAST PERIOD ARE TEMPERATURES FOR
WEDNESDAY AND THURSDAY...AS WELL AS PRECIPITATION CHANCES AND
TYPES FOR THURSDAY AND THURSDAY NIGHT.
THE SHORTWAVE TROUGH CURRENTLY OVER THE GULF OF ALASKA WILL SPLIT
WEDNESDAY AND WEDNESDAY NIGHT WHICH WILL IMPACT THE LOCAL AREA IN
DIFFERENT WAYS. ONE PART OF THIS ENERGY WILL DIG SOUTH ALONG THE
WEST COAST WHICH WILL HELP THE THERMAL RIDGE BUILD OVER THE PLAINS.
THE SECOND PIECE OF ENERGY WILL STAY IN THE NORTHERN STREAM WHICH
WILL MOVE ACROSS THE PLAINS AS A WEAK SHORTWAVE TROUGH THURSDAY AND
THURSDAY NIGHT...WHICH WILL PUSH AN ARCTIC COLD FRONT ACROSS THE
FORECAST AREA.
STARTING ON WEDNESDAY...IS STILL A QUESTION TO HOW WARM IT WILL GET.
AS MENTIONED ABOVE THE THERMAL RIDGE BUILDS IN WITH ANOMALOUSLY WARM
AIR SEEN ALOFT. AT 18Z WEDNESDAY MODELS INDICATE 850MB TEMPERATURES
WILL HAVE RISEN BETWEEN 11C AND 15C ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA. MODELS ARE ONLY MIXING THE BOUNDARY LAYER TO AROUND 875MB
SO DON/T REALIZE THE POTENTIAL WARMING. WINDS WILL BE FAIRLY LIGHT
WHICH WON/T HELP THE MIXING DEPTH...BUT DON/T THINK THE MODELS ARE
HANDLING THIS MIXING WELL AND IN MOST LOCATIONS WENT ABOVE MOST
GUIDANCE FOR HIGHS. MUCH OF THE NORTHERN TIER OF COUNTIES CONTINUES
TO HAVE SNOW ON THE GROUND WHICH AS OF MONDAY STILL HAD A STRONG
IMPACT ON TEMPERATURES AS HIGHS WERE ONLY IN THE LOW 40S...WITH
UPPER 50S AND LOW 60S OVER THE REST OF THE FORECAST AREA. SHOULD
HAVE CONTINUED MELTING TODAY...SO THE SNOW SHOULDN/T HAVE AS MUCH
IMPACT ON HIGHS...BUT WITH WET GROUND MAY NOT BE ABLE TO MIX TOO
MUCH SO CONTINUED THE TREND OF COOLER TEMPERATURES ACROSS THE NORTH.
THIS MAY NEED TO BE MODIFIED DEPENDING ON WHAT HIGHS DO TODAY.
COLD FRONT WILL PUSH SOUTH THROUGH THE FORECAST AREA WEDNESDAY
NIGHT...WITH THE COLDEST AIR LAGGING BEHIND THE FRONT. THE LOW
LEVELS START TO SATURATE BY 12Z THURSDAY BUT ABUNDANT DRY AIR IN THE
MID LEVELS WILL KEEP FROM THE NEED FOR PRECIPITATION CHANCES
WEDNESDAY NIGHT.
ON THURSDAY...THERE ARE STILL DISCREPANCIES AS TO HOW FAST THE COLD
AIR WILL MOVE IN. FOR EXAMPLE GFS ENSEMBLE MEMBERS VARY FROM 19F TO
42F FOR HIGHS AT KLBF. BECAUSE OF THESE DIFFERENCES STAYED FAIRLY
SIMILAR TO ONGOING FORECAST FOR HIGHS. WITH COLD AIR ADVECTION
THROUGH THE DAY...MAY SEE HIGHS EARLY WITH FALLING OR NEARLY STEADY
TEMPERATURES. IN TERMS OF PRECIPITATION FOR THURSDAY...THERE IS
AGREEMENT BETWEEN MODEL SOLUTIONS OF THE COLUMN BECOMING SATURATED
THURSDAY MORNING OVER THE NORTHERN PANHANDLE...AND WITH THE COLD AIR
ALREADY IN PLACE SHOULD START TO SEE SNOW IN THE MORNING HOURS. AS
THE ENTIRE COLUMN COOLS...WITH SOME LAYERS REACHING THE DENDRITIC
GROWTH ZONE...MIGHT GET SOME HIGHER SNOW TO LIQUID RATIO SNOWS UP
OVER NORTHWEST NEBRASKA. ACTUALLY...BY LATE THURSDAY NIGHT MOST OF
THE SOUNDING IS ISOTHERMAL IN THE DENDRITIC GROWTH ZONE.
HOWEVER...AT THIS POINT THE UPPER LEVEL SYSTEM IS WELL PAST AND THE
AREA IS IN AN AREA OF SUBSIDENCE AND LIFT IS MINIMAL SO THERE IS
ENOUGH DISCONNECT BETWEEN THE FAVORABLE CONDITIONS TO LIMIT FROM
HEAVY SNOWS. COULD SEE A COUPLE INCHES...POSSIBLY UP TO 4 ON THE
PINE RIDGE. WILL PROBABLY SEE SOME LIGHT SNOW ACROSS THE REST OF
NORTHERN NEBRASKA...BUT ONSET WILL BE LATER IN THE DAY THURSDAY AND
WITH THE UPWARD FORCING MOSTLY GONE BY MIDNIGHT EXPECT JUST LIGHT
AMOUNTS. DIFFERENT CONCERN IS FREEZING DRIZZLE FOR CENTRAL CHERRY
COUNTY AND EASTWARD ON THURSDAY. THE LOWEST 2500FT BECOME SATURATED
BY 18Z THURSDAY ACCORDING TO SOUNDINGS AT KVTN...WHILE A DEEP DRY
MID LAYER MAY PROHIBIT SEEDER FEEDER MECHANISM FROM OCCURRING FOR A
FEW HOURS. THERE IS DECENT OMEGA IN THESE LOW LEVELS SO DID ADD
CHANCES FOR FREEZING DRIZZLE INTO THE FORECAST FOR THURSDAY.
WILL ALSO BE QUITE WINDY ON THURSDAY AND THURSDAY NIGHT BEHIND THE
COLD FRONT WHICH WILL DROP WIND CHILLS TO AROUND -10F BY FRIDAY
MORNING.
LOOKING INTO THE WEEKEND...THE UPPER LOW OVER THE SOUTHWEST WILL
MIGRATE ACROSS THE SOUTHERN PLAINS WHILE THE LOCAL AREA WILL SEE
ANOTHER SHORTWAVE TROUGH MOVE ACROSS THE AREA THROUGH THE NORTHERN
STREAM. THERE IS SOME DIFFERENCES ON TIMING OF THIS NEXT
SYSTEM...BUT SHOULD BE MOVING THROUGH SOMETIME SATURDAY NIGHT/SUNDAY.
DOESN/T LOOK LIKE MUCH FOR PRECIPITATION WITH THIS NEXT SYSTEM BUT
THERE IS POTENTIAL FOR ANOTHER PUSH OF ARCTIC AIR INTO THE AREA
BEHIND IT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 520 AM CST TUE DEC 17 2013
SFC LOW PRESSURE WILL TRACK ACROSS SRN CANADA TODAY AND TONIGHT. VFR
IS EXPECTED ALL AREAS WITH SCATTERED MID AND HIGH LEVEL CLOUDS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1106 AM EST TUE DEC 17 2013
.SYNOPSIS...
LOW PRESSURE WAS OVER LAKE ERIE WITH A COLD FRONT TRAILING INTO
MISSOURI. THIS LOW WILL MOVE EAST TODAY PUSHING THE COLD FRONT
THROUGH THE REGION. WEDNESDAY AND THURSDAY HIGH PRESSURE WILL BE
OVER THE AREA.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
AS OF 1052 AM EST TUESDAY...
STOUT UPPER WAVE/CLIPPER AS USUAL LOOKING TO OUTPERFORM MODEL RUNS
FROM THE PAST FEW DAYS. ENOUGH QPF AND COLD AIR WITH THIS SYSTEM
TO PRODUCE ADVISORY CRITERIA SNOW ACROSS THE HIGHEST TERRITORY OF
GREENBRIER AND SUMMERS THIS AFTERNOON AND EARLY EVENING.
NAM/GFS/SREF HAVE 6HR QPF PRETTY CLOSE TO 0.3" WHEN AIR IS COLD
ENOUGH FOR SNOW ABOVE 2500 FEET FROM 18Z/1P-0Z/7P. POTENTIAL FOR
A BURST OF SNOW THAT PUTS DOWN A QUICK HALF INCH THIS AFTERNOON
COULD COMPLICATE RUSH HOUR TRAVEL/SCHOOLS LETTING OUT. WOULD NOT
BE SURPRISED BY A 2-4" SNOWFALL BY THIS EVENING ACROSS THE
WESTERN SLOPES ABOVE 2500 FEET SUMMERS/GREENBRIER. NOT OUT OF THE
QUESTION THAT EVEN SOME OF THE CITIES AT LOWER ELEVATIONS PICK UP
A QUICK COATING/HALF INCH WHEN THE CHANGEOVER OCCURS THIS
AFTERNOON. HOWEVER...SLOWER CHANGEOVER AND WET GROUND MAY MITIGATE
ACCUMS GREATLY AT THE LOWER ELEVATIONS.
BACK EAST THROUGH THE NEW RIVER VALLEY/SOUTHSIDE/PIEDMONT....WINDS
MAY GUST TO 25 KTS AS CLOUDS BEGIN TO COVER MOST OF THE CWA...BUT
AROUND 35 KTS NW NC NEAR SUNSET. DOWNSLOPE WARMING THIS PM MAY BE
STUNTED BY THE OVERCAST. SINCE THIS DOWNSLOPE FLOW IS MORE OF THE
WESTERLY VARIETY AS OPPOSED TO NW-NNW...POSSIBLE THAT SOME OF THE
PRECIP FROM THIS SYSTEM SNEAKS THROUGH SE WEST VA AND MAYBE ENTERS
THE NEW RIVER VALLEY LATE THIS AFTERNOON OR EVENING...POSSIBLY AS
SNOW SHOWERS. WILL BE TAKING A FURTHER LOOK AT THIS FOR THE
AFTERNOON PACKAGE.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH FRIDAY NIGHT/...
AS OF 300 AM EST TUESDAY...
COLD ADVECTION SETS IN BEHIND THE FRONT. THE BEST PRESSURE RISES
WILL BE TONIGHT...PEAKING AROUND 06Z. WINDS WILL BE CLOSE TO
ADVISORY CRITERIA OF 40 KNOT GUSTS FROM GRAYSON COUNTY SOUTH TO
WATAUGA COUNT
DURING THE DAY WEDNESDAY...THE PRESSURE GRADIENT WEAKENS AS SURFACE
HIGH PRESSURE BUILD OVER THE REGION AND THE UPPER LEVEL SHORTWAVE
TROUGH MOVES INTO THE WESTERN ATLANTIC. THE IMPACT ON OUR REGION
WILL BE A GRADUAL DECREASE TO BOTH THE WIND SPEED ACROSS THE
REGION...AND THE UPSLOPE SNOW SHOWERS ACROSS WESTERN GREENBRIER
COUNTY WV.
WEDNESDAY NIGHT INTO THURSDAY...WILL BEGIN A PERIOD OF MILDER
CONDITIONS ACROSS THE AREA AS THE CENTER OF THE SURFACE HIGH SHIFTS
TO THE COAST AND THERE IS A DEVELOPMENT OF A TROUGH ACROSS THE
CENTRAL PORTION OF THE COUNTRY. THE RESULT WILL BE AN INCREASING
SOUTHWESTERLY FLOW AND WARM AIR ADVECTION ACROSS THE REGION.
THIS PATTERN WILL CONTINUE INTO FRIDAY AS THE UPPER TROUGH CONTINUES
TO STRENGTHEN. ALSO...A DECENT FETCH OF MOISTURE WILL DEVELOP FROM
OFF THE GULF OF MEXICO ALONG THE EAST SIDE OF THE TROUGH THAT WILL
EXTEND FROM THE LOWER MISSISSIPPI VALLEY NORTHEAST INTO THE OHIO
VALLEY. THIS MOISTURE WILL GRADUALLY PROGRESS EASTWARD AS THE TROUGH
EJECTS EASTWARD BY LATE FRIDAY NIGHT. THE RESULT FOR OUR REGION WILL
BE A CONTINUED TREND OF MILDER TEMPERATURES AND INCREASING CHANCES
OF PRECIPITATION...ESPECIALLY IN THE WEST...LATE FRIDAY INTO FRIDAY
NIGHT.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 253 PM EST MONDAY...
A MILD WEEKEND EXPECTED WITH A COOL DOWN FOR EARLY NEXT WEEK. A COLD
FRONT WITH SEVERAL WAVES OF LOW PRESSURE ALONG IT WILL TRAVEL EAST
AND ADVANCE THROUGH OUR REGION BY SUNDAY NIGHT. SOUTHWEST FLOW AND
INCREASING HEIGHTS WILL RESULT IN WARMER THAN NORMAL TEMPERATURES ON
FRIDAY. AS THE FRONT APPROACHES FROM THE OHIO VALLEY FRIDAY WILL
ALLOW FOR LIGHT POPS IN THE MOUNTAINS ON FRIDAY.
A WAVE OF LOW PRESSURE RIDING NORTH ALONG THE BOUNDARY WILL PUSH
THE COLD FRONT CLOSER TO US ON SATURDAY. POPS INCREASE FOR THE
ENTIRE FORECAST AREA ON SATURDAY AS THE FRONT EDGES CLOSER.
UNSEASONABLY WARM TEMPERATURES EXPECTED FOR SATURDAY WITH HIGHS
FROM MID 50S IN THE MOUNTAINS TO NEAR 70 DEGREES IN SOUTHEAST. IN
GENERAL...KEPT SCATTERED POPS FOR SATURDAY AND SATURDAY NIGHT. THE
WAVE THAT LIFTS NORTH ALONG THE BOUNDARY SATURDAY NIGHT MAY SLOW
ITS ADVANCE EAST SATURDAY NIGHT INTO SUNDAY. PLAYED LOWS SATURDAY
NIGHT WITH READINGS FROM THE UPPER 40S IN THE WEST TO MID 50S IN
THE EAST. LEANED TOWARDS THE SLOWER TIMING OF THE COLD FRONT ON
SUNDAY COMPARED TO GFS.
HIGHS ON SUNDAY WILL RANGE FROM AROUND 60 DEGREES IN THE WEST TO
APPROACHING 70 DEGREES IN THE EAST. LOW TEMPERATURES SUNDAY NIGHT
WILL BE DEPENDING ON TIMING OF LOW PRESSURE AND ITS MOVEMENT.
LEANED TOWARDS ECMWF ENSEMBLE WITH VALUES FROM THE MID 30S IN THE
NORTHWEST TO AROUND 50 DEGREES IN THE SOUTHEAST. MORE SEASONABLE
WEATHER RETURNS ON MONDAY WITH A CHANCE OF SHOWERS AND HIGHS IN
THE LOWER 40S IN THE MOUNTAINS TO THE MID 50S IN THE PIEDMONT.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
AS OF 700 AM EST TUESDAY...
SHORT WAVE CROSSING THE OHIO VALLEY AND ASSOCIATED WARM AIR
ADVECTION WAS PRODUCING LIGHT PRECIPITATION IN WEST VIRGINIA THIS
MORNING. ICING IS POSSIBLE AROUND LEWISBURG WHERE THE TEMPERATURE
WAS STILL BELOW FREEZING. OTHERWISE THIS MORNING EXPECT MID AND
HIGH CLOUDS EAST OF THE BLUE RIDGE.
A STRONGER SHORT WAVE CROSSES THROUGH THE AREA THIS AFTERNOON AND
EVENING. LOCAL WRF AND THE LAST FEW RUNS OF THE RAP MODELS
INDICATED THE HIGHEST PROBABILITY OF PRECIPITATION WILL BE IN THE
MOUNTAINS AND ON THE WESTERN SLOPES WHERE GOOD SYNOPTIC SCALE LIFT
WILL COMBINE WITH UPSLOPE FLOW TO PRODUCE PRECIPITATION. HIGH
CONFIDENCE OF SNOW AND MVFR CEILINGS AND VISIBILITIES NEAR KBLF
AND KLWB AROUND 00Z TONIGHT. MUCH LOWER CONFIDENCE ABOUT THE
CHANCE OF SHOWERS IN CENTRAL VIRGINIA AND NORTH CAROLINA LATE THIS
AFTERNOON ALONG A COLD FRONT THAT WILL BE MOVING THROUGH THE
REGION.
BEHIND THE FRONT TONIGHT WINDS WILL BE STRONG AND GUSTY. WIND
GUSTS OF 25 TO 25 KNOTS WILL BE COMMON IN THE MOUNTAINS...
ESPECIALLY ALONG THE RIDGES. MVFR CLOUDS WILL PERSIST AT KLWB AND
KBLF. WINDS WILL BEGIN TO DIMINISH WEDNESDAY MORNING AS HIGH
PRESSURE BUILDS INTO THE AREA.
HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE INTO THURSDAY.
THE WEATHER WILL BE DETERIORATING FOR THE WEEKEND AS NEXT LOW
PRESSURE SYSTEM MOVES IN FROM THE WEST WITH PRECIPITATION AND MVFR
OR LOWER CONDITIONS EXPECTED. A COLD FRONT WITH SEVERAL WAVES OF
LOW PRESSURE ALONG IT WILL TRAVEL EAST AND ADVANCE THROUGH OUR
REGION BY SUNDAY NIGHT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...KM
SHORT TERM...AMS/DS
LONG TERM...KK
AVIATION...AMS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
711 AM EST TUE DEC 17 2013
.SYNOPSIS...
LOW PRESSURE WAS OVER LAKE ERIE WITH A COLD FRONT TRAILING INTO
MISSOURI. THIS LOW WILL MOVE EAST TODAY PUSHING THE COLD FRONT
THROUGH THE REGION. WEDNESDAY AND THURSDAY HIGH PRESSURE WILL BE
OVER THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM EST TUESDAY...
WARM ADVECTION HAD BROUGHT TEMPERATURES UP SINCE MIDNIGHT. SOME LIGHT
PRECIPITATION TO THE WEST OF THE COUNTY WARNING AREA WAS DEVELOPING
JUST WEST OF THE FORECAST AREA. CLOUDS HAVE LOWERED AT HOT SPRINGS
AND LEWISBURG SO MORE CONFIDENCE NOW THAT PRECIPITATION IN THE FAR
NORTHWEST CORNER OF THE FORECAST AREA MAY BE REACHING THE GROUND.
A SURFACE LOW PRESSURE SYSTEM OVER OHIO EARLY THIS MORNING WILL MOVE
EAST...PULLING A WARM FRONT NORTH THROUGH THE MID ATLANTIC STATES
THIS MORNING AND BRINGING A COLD FRONT INTO THE MOUNTAINS THIS
AFTERNOON. HAVE ADDED A LOW PROBABILITY OF SHOWERS EAST OF
DANVILLE AND LYNCHBURG THIS EVENING. LAPSE RATES AND FORCING WILL
BE GOOD BUT WILL HAVE TO OVERCOME DOWNSLOPE WINDS.
COLD ADVECTION SETS IN BEHIND THE FRONT. THE BEST PRESSURE RISES
WILL BE TONIGHT...PEAKING AROUND 06Z. WINDS WILL BE CLOSE TO
ADVISORY CRITERIA OF 40 KNOT GUSTS FROM GRAYSON COUNTY SOUTH TO
WATAUGA COUNTY SO WIND ADVISORY MAY BE ISSUED LATER THIS MORNING.
A STRONG SHORT WAVE OVER THE UPPER MISSISSIPPI VALLEY WILL TRACK
TOWARD THE MID ATLANTIC REGION TODAY AND CROSS THE FORECAST AREA
THIS EVENING. BY THEN THE COLD FRONT WILL BE THROUGH AND
TEMPERATURES WILL BE COLD ENOUGH FOR SNOW. EXPANDING PROBABILITY OF
PRECIPITATION INTO THE NORTHWEST NORTH CAROLINA MOUNTAINS BY LATE
AFTERNOON...FOLLOWING THE TRACK OF THE SHORT WAVE ON THE SREF AND
LATEST LOCAL WRF MODELS. THERMAL PROFILE FROM THE NAM BUFKIT AT
BLUEFIELD AND LEWISBURG START OUT AS RAIN IN THE LATE AFTERNOON THEN
CHANGE TO SNOW BY 00Z. LOCAL WRF WAS SLIGHTLY COLDER...SHOWING THE
EVENT BEGINNING AS SNOW.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM EST TUESDAY...
DURING THE DAY WEDNESDAY...THE PRESSURE GRADIENT WEAKENS AS SURFACE
HIGH PRESSURE BUILD OVER THE REGION AND THE UPPER LEVEL SHORTWAVE
TROUGH MOVES INTO THE WESTERN ATLANTIC. THE IMPACT ON OUR REGION
WILL BE A GRADUAL DECREASE TO BOTH THE WIND SPEED ACROSS THE
REGION...AND THE UPSLOPE SNOW SHOWERS ACROSS WESTERN GREENBRIER
COUNTY WV.
WEDNESDAY NIGHT INTO THURSDAY...WILL BEGIN A PERIOD OF MILDER
CONDITIONS ACROSS THE AREA AS THE CENTER OF THE SURFACE HIGH SHIFTS
TO THE COAST AND THERE IS A DEVELOPMENT OF A TROUGH ACROSS THE
CENTRAL PORTION OF THE COUNTRY. THE RESULT WILL BE AN INCREASING
SOUTHWESTERLY FLOW AND WARM AIR ADVECTION ACROSS THE REGION.
THIS PATTERN WILL CONTINUE INTO FRIDAY AS THE UPPER TROUGH CONTINUES
TO STRENGTHEN. ALSO...A DECENT FETCH OF MOISTURE WILL DEVELOP FROM
OFF THE GULF OF MEXICO ALONG THE EAST SIDE OF THE TROUGH THAT WILL
EXTEND FROM THE LOWER MISSISSIPPI VALLEY NORTHEAST INTO THE OHIO
VALLEY. THIS MOISTURE WILL GRADUALLY PROGRESS EASTWARD AS THE TROUGH
EJECTS EASTWARD BY LATE FRIDAY NIGHT. THE RESULT FOR OUR REGION WILL
BE A CONTINUED TREND OF MILDER TEMPERATURES AND INCREASING CHANCES
OF PRECIPITATION...ESPECIALLY IN THE WEST...LATE FRIDAY INTO FRIDAY
NIGHT.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 253 PM EST MONDAY...
A MILD WEEKEND EXPECTED WITH A COOL DOWN FOR EARLY NEXT WEEK. A COLD
FRONT WITH SEVERAL WAVES OF LOW PRESSURE ALONG IT WILL TRAVEL EAST
AND ADVANCE THROUGH OUR REGION BY SUNDAY NIGHT. SOUTHWEST FLOW AND
INCREASING HEIGHTS WILL RESULT IN WARMER THAN NORMAL TEMPERATURES ON
FRIDAY. AS THE FRONT APPROACHES FROM THE OHIO VALLEY FRIDAY WILL
ALLOW FOR LIGHT POPS IN THE MOUNTAINS ON FRIDAY.
A WAVE OF LOW PRESSURE RIDING NORTH ALONG THE BOUNDARY WILL PUSH
THE COLD FRONT CLOSER TO US ON SATURDAY. POPS INCREASE FOR THE
ENTIRE FORECAST AREA ON SATURDAY AS THE FRONT EDGES CLOSER.
UNSEASONABLY WARM TEMPERATURES EXPECTED FOR SATURDAY WITH HIGHS
FROM MID 50S IN THE MOUNTAINS TO NEAR 70 DEGREES IN SOUTHEAST. IN
GENERAL...KEPT SCATTERED POPS FOR SATURDAY AND SATURDAY NIGHT. THE
WAVE THAT LIFTS NORTH ALONG THE BOUNDARY SATURDAY NIGHT MAY SLOW
ITS ADVANCE EAST SATURDAY NIGHT INTO SUNDAY. PLAYED LOWS SATURDAY
NIGHT WITH READINGS FROM THE UPPER 40S IN THE WEST TO MID 50S IN
THE EAST. LEANED TOWARDS THE SLOWER TIMING OF THE COLD FRONT ON
SUNDAY COMPARED TO GFS.
HIGHS ON SUNDAY WILL RANGE FROM AROUND 60 DEGREES IN THE WEST TO
APPROACHING 70 DEGREES IN THE EAST. LOW TEMPERATURES SUNDAY NIGHT
WILL BE DEPENDING ON TIMING OF LOW PRESSURE AND ITS MOVEMENT.
LEANED TOWARDS ECMWF ENSEMBLE WITH VALUES FROM THE MID 30S IN THE
NORTHWEST TO AROUND 50 DEGREES IN THE SOUTHEAST. MORE SEASONABLE
WEATHER RETURNS ON MONDAY WITH A CHANCE OF SHOWERS AND HIGHS IN
THE LOWER 40S IN THE MOUNTAINS TO THE MID 50S IN THE PIEDMONT.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 700 AM EST TUESDAY...
SHORT WAVE CROSSING THE OHIO VALLEY AND ASSOCIATED WARM AIR
ADVECTION WAS PRODUCING LIGHT PRECIPITATION IN WEST VIRGINIA THIS
MORNING. ICING IS POSSIBLE AROUND LEWISBURG WHERE THE TEMPERATURE
WAS STILL BELOW FREEZING. OTHERWISE THIS MORNING EXPECT MID AND
HIGH CLOUDS EAST OF THE BLUE RIDGE.
A STRONGER SHORT WAVE CROSSES THROUGH THE AREA THIS AFTERNOON AND
EVENING. LOCAL WRF AND THE LAST FEW RUNS OF THE RAP MODELS
INDICATED THE HIGHEST PROBABILITY OF PRECIPITATION WILL BE IN THE
MOUNTAINS AND ON THE WESTERN SLOPES WHERE GOOD SYNOPTIC SCALE LIFT
WILL COMBINE WITH UPSLOPE FLOW TO PRODUCE PRECIPITATION. HIGH
CONFIDENCE OF SNOW AND MVFR CEILINGS AND VISIBILITIES NEAR KBLF
AND KLWB AROUND 00Z TONIGHT. MUCH LOWER CONFIDENCE ABOUT THE
CHANCE OF SHOWERS IN CENTRAL VIRGINIA AND NORTH CAROLINA LATE THIS
AFTERNOON ALONG A COLD FRONT THAT WILL BE MOVING THROUGH THE
REGION.
BEHIND THE FRONT TONIGHT WINDS WILL BE STRONG AND GUSTY. WIND
GUSTS OF 25 TO 25 KNOTS WILL BE COMMON IN THE MOUNTAINS...
ESPECIALLY ALONG THE RIDGES. MVFR CLOUDS WILL PERSIST AT KLWB AND
KBLF. WINDS WILL BEGIN TO DIMINISH WEDNESDAY MORNING AS HIGH
PRESSURE BUILDS INTO THE AREA.
HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE INTO THURSDAY.
THE WEATHER WILL BE DETERIORATING FOR THE WEEKEND AS NEXT LOW
PRESSURE SYSTEM MOVES IN FROM THE WEST WITH PRECIPITATION AND MVFR
OR LOWER CONDITIONS EXPECTED. A COLD FRONT WITH SEVERAL WAVES OF
LOW PRESSURE ALONG IT WILL TRAVEL EAST AND ADVANCE THROUGH OUR
REGION BY SUNDAY NIGHT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...DS
LONG TERM...KK
AVIATION...AMS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
408 AM CST TUE DEC 17 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CST TUE DEC 17 2013
FORECAST CONCERNS ARE ON SNOW CHANCES TODAY. FOCUS THEN QUICKLY TURNS
TO STORM SYSTEM IMPACTING THE REGION THURSDAY INTO THURSDAY NIGHT
WITH THE POTENTIAL FOR LIGHT FREEZING RAIN AND SNOW.
AT 3 AM...WATER VAPOR IMAGERY SHOWED A WEAK SHORTWAVE PUSHING ACROSS
THE FORECAST AREA PRODUCING LIGHT SNOW AS IT MOVES THROUGH. THE
WAVE WILL EXIT THE AREA QUICKLY THIS MORNING BUT ANOTHER WAVE WAS
RIGHT BEHIND THE FIRST AND WAS MOVING ACROSS EASTERN NORTH DAKOTA.
THIS SECOND WAVE WILL BRING COLDER AIR ALOFT WITH IT...WITH 850 MB
TEMPERATURES GOING FROM -7C OVER THE AREA EARLY THIS MORNING TO
-17C BY LATE THIS AFTERNOON. THIS COLDER AIR ALOFT WILL STEEPEN
THE 1000-850 MB LAPSE RATES...LEADING TO SCATTERED SNOW SHOWERS
AND GUSTY WINDS FROM LATE THIS MORNING THROUGH THE AFTERNOON
HOURS. THE MOISTURE LOOKS LIMITED OVER SOUTHEAST MINNESOTA AND
NORTHEAST IOWA...ESPECIALLY WEST OF HIGHWAY 52. AREAS EAST OF
HIGHWAY 52 THROUGH WESTERN INTO CENTRAL WISCONSIN CAN EXPECT A FEW
PASSING SNOW SHOWERS TODAY WITH THE POTENTIAL TO PICK UP A FEW
TENTHS OF ACCUMULATION. LOCATIONS OVER CENTRAL INTO NORTH CENTRAL
WISCONSIN HAVE THE BEST CHANCES OF SEEING SOME LIGHT
ACCUMULATIONS. OTHERWISE...NORTHWEST WINDS WILL PICK UP TODAY INTO
THE 15 TO 25 MPH RANGE WITH SOME GUSTS AROUND 35 MPH OVER THE OPEN
AREAS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA. THESE WINDS WILL
PRODUCE SOME PATCHY BLOWING SNOW AND AREAS OF DRIFTING SNOW WHICH
COULD LEAD TO SOME SLICK SPOTS ON AREA ROADS. HIGH PRESSURE MOVES
OVER THE REGION TONIGHT WITH QUIET WEATHER EXPECTED. PLAN ON A
CHILLY NIGHT WITH LOWS RANGING FROM THE SINGLE DIGITS BELOW ZERO
OVER NORTH CENTRAL WISCONSIN TO THE TEENS ACROSS NORTHEAST IOWA.
THESE LOWS SHOULD OCCUR EARLY IN THE NIGHT. A WARM FRONT THEN
PUSHES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY LATE TONIGHT INTO
EARLY WEDNESDAY MORNING AS A TROUGH DIVES INTO THE THE WEST COAST.
TEMPERATURES ARE EXPECTED TO GRADUALLY RISE EARLY WEDNESDAY
MORNING IN THE WAKE OF THE FRONT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 408 AM CST TUE DEC 17 2013
LOW PRESSURE WILL DEVELOP OVER THE NORTHERN PLAINS ON
WEDNESDAY...LEADING TO A TIGHT PRESSURE GRADIENT OVER THE UPPER
MISSISSIPPI RIVER VALLEY. SOUTH/SOUTHWEST WINDS AHEAD OF THE LOW
WILL HELP TO USHER IN A WARMER AIRMASS. 850 MB TEMPERATURES START
OUT AT - 3C EARLY WEDNESDAY MORNING BUT THEN WARM TO +7C BY EARLY
WEDNESDAY EVENING. THE WARM AIR STAYS WELL ALOFT THROUGH THE DAY
BUT WE SHOULD STILL SEE HIGH TEMPERATURES WARM INTO THE 30S ACROSS
MUCH OF THE FORECAST AREA. THE ONLY EXCEPTION WILL BE OVER NORTH
CENTRAL WISCONSIN WHERE HIGHS ARE EXPECTED TO REACH INTO THE MID
20S.
A FRONTAL BOUNDARY THEN SLIDES SOUTH ACROSS THE AREA LATE
WEDNESDAY NIGHT INTO THURSDAY MORNING AS A TROUGH CONTINUES TO
DEEPEN OVER THE SOUTHWEST CONUS. THE FRONT IS EXPECTED TO STALL
OVER CENTRAL IOWA THROUGH SOUTH CENTRAL WISCONSIN. THE BOUNDARY
WILL INTERACT WITH A SHORTWAVE MOVING ACROSS THE NORTHERN PLAINS
AND THE RIGHT ENTRANCE REGION OF A 250 MB JET TO PRODUCE LIGHT
SNOW AND FREEZING DRIZZLE FROM THURSDAY AFTERNOON THROUGH THURSDAY
NIGHT. FORECAST SOUNDINGS SHOW ICE ALOFT FOR LOCATIONS NORTH OF
INTERSTATE 90 BY THE TIME THE PRECIPITATION DEVELOPS LATE IN THE
AFTERNOON. HOWEVER...FOR AREAS SOUTH OF INTERSTATE 90 THERE ISN/T
ICE ALOFT WITH SOUNDINGS SHOWING A NEARLY SATURATED LAYER FROM THE
SURFACE THROUGH 2KFT WITH WEAK OMEGA WITHIN THIS LAYER. THIS
SHOULD LEAD TO AREAS OF FREEZING DRIZZLE OVER NORTHEAST IOWA INTO
SOUTHWEST WISCONSIN EARLY THURSDAY MORNING. THE FREEZING DRIZZLE
SHOULD GRADUALLY SWITCH OVER TO SNOW THURSDAY NIGHT AS COOLER AIR
MOVES IN FROM THE NORTH AND SATURATION OCCURS ALOFT. WILL HAVE TO
KEEP A VERY CLOSE EYE ON THE FORECAST MODELS THE NEXT FEW RUNS.
THE ECMWF/GEM/GFS ARE IN AGREEMENT WITH THIS SCENARIO BUT THE NAM
IS SHOWING THE FREEZING DRIZZLE DEVELOPING LATE WEDNESDAY NIGHT
OVER NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN. THE 17.06 NAM IS
NOW SHOWING A DRIZZLE SIGNATURE IN THE QPF FIELDS OVER THESE
AREAS. WILL LEAN TOWARD THE ECMWF/GEM/GFS. HEADLINES MAY BE NEEDED
OVER THESE AREAS FOR LIGHT ICE ACCUMULATIONS WHICH COULD LEAD TO
DANGEROUS TRAVEL CONDITIONS. FORECAST MODELS ARE ALSO TRENDING A
LITTLE COOLER WITH TEMPERATURES ON THURSDAY WITH MOST OF THE AREA
NOT GETTING ABOVE THE FREEZING MARK...WHICH RAISES ADDITIONAL
CONCERN FOR THE FREEZING DRIZZLE POTENTIAL. PLAN ON AREAS OF FOG
WEDNESDAY NIGHT THROUGH THURSDAY FOR AREAS ALONG AND SOUTH OF
INTERSTATE 90. THE FOG MAY BE DENSE AT TIMES...ESPECIALLY ACROSS
NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN. THE PRECIPITATION
SHOULD TURN OVER TO ALL SNOW BY EARLY FRIDAY MORNING. AT THIS TIME
IT APPEARS SNOW ACCUMULATIONS OF 1 TO 3 INCHES ARE POSSIBLE ALONG
AND NORTH OF I-90. A GLAZE TO AROUND A TENTH OF AN INCH OF ICING
IS POSSIBLE SOUTH OF I-90. ONCE THE FREEZING DRIZZLE SWITCHES OVER
TO SNOW...ACCUMULATIONS OF AROUND 1/2 INCH ARE POSSIBLE. THERE IS
CONSIDERABLE UNCERTAINTY REGARDING THE TIMING AND PLACEMENT OF THE
PRECIPITATION SO WILL HAVE TO KEEP A CLOSE EYE ON MODEL TRENDS
TODAY AND TONIGHT.
PRECIPITATION WILL END EARLY ON FRIDAY AS THE SYSTEM EXITS.
SLIGHTLY COOLER TEMPERATURES MOVE BACK INTO THE REGION FOR THIS
WEEKEND WITH HIGHS IN THE UPPER TEENS TO MID 20S BOTH FRIDAY AND
SATURDAY. PLAN ON OVERNIGHT LOWS DIPPING INTO THE SINGLE DIGITS. A
FEW WEAK DISTURBANCES COULD BRING SOME LIGHT SNOW TO THE AREA BUT
ACCUMULATIONS APPEAR MINOR AT THIS TIME. A STRONGER SYSTEM THEN
LIFTS NORTHEAST OUT OF MEXICO SATURDAY AND HEADS FOR THE OHIO RIVER
VALLEY LATE SATURDAY NIGHT INTO SUNDAY MORNING. THIS SYSTEM WILL
JUST GLANCE SOUTHWEST SECTIONS OF THE FORECAST AREA BRINGING LIGHT
SNOW TO PORTIONS OF NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN.
THERE WILL BE A BREAK IN THE PRECIPITATION CHANCES SUNDAY NIGHT
BEFORE ANOTHER WEAK SYSTEM MOVES THROUGH ON MONDAY BRINGING SLIGHT
CHANCES FOR LIGHT SNOW. IT WILL REMAIN ON THE COOL SIDE FOR THIS
TIME OF YEAR GOING INTO NEXT WEEK WITH HIGHS IN THE TEENS AND LOWS
IN THE SINGLE DIGITS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1140 PM CST MON DEC 16 2013
THE NEXT BAND OF LIGHT SNOW WAS STARTING TO TAKE SHAPE OVER
CENTRAL AND NORTHERN MINNESOTA. THE SHORT WAVE TROUGH WITH THIS
BAND OF SNOW LOOKS TO TRACK FARTHER TO THE NORTH THAN PREVIOUSLY
EXPECTED. THIS HAS RESULTED IN A NORTHWARD SHIFT OF WHERE THE SNOW
SHOULD FALL AS WELL AND IT NOW COULD BE QUITE POSSIBLE THAT
NEITHER TAF SITE COULD SEE ANY SNOW. KLSE LOOKS TO HAVE A SLIGHTLY
BETTER CHANCE OF BEING BRUSHED BY THE SOUTHERN EXTENT OF THE SNOW
BAND AND HAVE SHOWN A SHORT PERIOD OF PREVAILING MVFR WITH THE
POSSIBILITY OF IFR...BUT CONFIDENCE IS NOT HIGH IN THIS AT ALL.
FOR KRST...HAVE GONE TO PREVAILING VFR OVERNIGHT WITH A
POSSIBILITY OF MVFR IF THE SNOW BAND CAN REACH THE AIRPORT. THE
SNOW CHANCES WILL END BEFORE SUNRISE AS A COLD FRONT GOES
THROUGH. THE 17.00Z NAM AND 18.03Z RAP NOW BOTH SHOW THE INVERSION
HOLDING TOUGH BEHIND THE FRONT UNTIL MID MORNING. ONCE THE
INVERSION MIXES OUT...GOOD LOW LEVEL LAPSE RATES DEVELOP THAT WILL
ALLOW FOR SUSTAINED NORTHWEST WINDS BETWEEN 15 AND 20 KNOTS WITH
GUSTS OF BETWEEN 25 AND 30 KT. THIS WILL LIKELY PRODUCE A LOT OF
DRIFTING SNOW AND POSSIBLY A LITTLE BIT OF BLOWING SNOW AT KRST.
THERE SHOULD ALSO BE ENOUGH RESIDUAL LOW LEVEL MOISTURE TO ALLOW
A MVFR CEILING TO DEVELOP ON TOP OF THE INSTABILITY LAYER. THE
INVERSION WILL REDEVELOP EARLY TUESDAY EVENING ALLOWING THE WINDS
TO SETTLE DOWN TO AROUND 10 KNOTS ENDING THE BLOWING SNOW AND MVFR
CEILINGS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
959 AM MST TUE DEC 17 2013
.UPDATE...
&&
.SHORT TERM...CURRENT FORECASTS SEEM REASONABLE. WEST NORTHWEST
FLOW CURRENTLY OVER THE REGION. SOME GUSTS FROM 25 TO 30 KTS
CURRENTLY IN AND NEAR FOOTHILLS...THOUGH NOT THAT WIDESPREAD.
THERE WILL BE SOME MIXING BY THE AFTERNOON WHICH WILL HELP
WESTERLY WINDS SPREAD FURTHER EAST ALONG THE URBAN CORRIDOR WITH
A MORE SOUTHERLY DIRECTION AWAY FROM THE URBAN CORRIDOR. WARMER
AIRMASS AND MIXING WILL HELP WITH WARMUP TODAY...WITH LOWER TO MID
60S POSSIBLE ACROSS THE PLAINS. SOME INCREASE IN WIND TONIGHT IN
AND NEAR FOOTHILLS AS FLOW ALOFT BECOMES A BIT MORE WESTERLY AND
CROSS MOUNTAIN FLOW INCREASES TO AROUND 40 KTS. OVERNIGHT
TEMPERATURES TO BE FAIRLY MILD WITH SOME MODERATION IN LOW LYING
AREAS.
.AVIATION...WINDS CURRENTLY SOUTHEAST AT KDEN AND KAPA WHILE
WESTERLY AT KBJC. STILL EXPECTING SOME MIXING OF THE WESTERLY
WINDS ACROSS THE AREA AIRPORTS BY 20Z. LATEST RAP AND HRRR
INDICATING WINDS AT KDEN AND KAPA TO CONTINUE SOUTHEAST FOR MUCH
OF THE AFTERNOON. FOR NOW WILL CONTINUE THE TREND OF THE CURRENT
TAFS...THINKING THAT THE MIXING WILL OVERCOME THE SOUTHEAST
DIRECTION THIS AFTERNOON. ENHANCED DRAINAGE FLOW EXPECTED THIS
EVENING. VFR WILL CONTINUE. SOME POTENTIAL FOR WAVE CLOUD IN AND
NEAR FOOTHILLS AFTER 08Z. CEILINGS SHOULD REMAIN ABOVE 12000 FEET
AGL.
&&
.PREV DISCUSSION... /ISSUED 411 AM MST TUE DEC 17 2013/
SHORT TERM...WNW FLOW CONTINUES TODAY WITH LITTLE CHANGE TO THE
WIND FIELD OTHER THAN WEAK MIXING WITH HEATING DURING THE DAY IN
THE LOWER ELEVATIONS. TEMPERATURES SHOULD GET A LITTLE WARMER THAN
YESTERDAY. STILL A FEW WAVE CLOUDS AROUND...COULD BE SOME
ENHANCEMENT FOR A WHILE THIS MORNING. BETWEEN TODAYS WARMING AND
CONTINUED BREEZES OVERNIGHT LOWS SHOULD ALSO CONTINUE A WARMING
TREND...PRETTY MILD IN MOST AREAS AND COLDER BUT STILL MODERATING
A BIT IN THE LOW SPOTS.
LONG TERM...ON WEDNESDAY...A MODERATE TO STRONG W/SWLY FLOW
ALOFT WILL BE OVER COLORADO...WITH A SURFACE TROUGH DEVELOPING
OVER THE EASTERN PLAINS THROUGH THE DAY. THIS WILL ADD UP TO AN
UNSEASONABLE MILD AFTN ESPECIALLY IN AND NEAR THE FRONT RANGE
FOOTHILLS WHERE DOWNSLOPE WLY WINDS WILL DEVELOP. TEMPERATURES ARE
PROGGED TO CLIMB INTO THE MID 60S FOR DENVER...THE RECORD HIGH FOR
THE DATE IS 66 DEGREES WHICH COULD BE BROKEN. THE NAM12/GFS40 SPATIAL
CROSS-SECTIONS CONTINUES TO DEVELOP STRONG GUSTY WINDS IN THE
MOUNTAINS AND HIGHER FOOTHILLS WITH A 50 KT CROSS-MTN COMPONENT AT
750 MB. DO NOT EXPECTED WARNING CRITERIA WINDS BUT OVERNIGHT LOWS
IN THE FOOTHILLS WILL BE VERY MILD WITH SOME GUSTS TO 50 MPH
POSSIBLE. THE FLOW ALOFT WILL CONTINUE TO INCREASE ON
THURSDAY...WITH A 90 KT JET OVERHEAD. THE FLOW ALOFT WILL BE
SOUTHWESTERLY WITH THE INCOMING TROUGH SLOWS DOWN AND SPLITS. THE
NORTHERN BRANCH WILL MOVE ACROSS THE NRN TIER STATES WHILE THE SRN
BRANCH DEVELOPING INTO A CLOSED LOW OVER SRN CA. IT WILL BE FAIRLY
MILD THURSDAY MORNING AHEAD OF AN APPROACHING COLD FRONT WHICH
SHOULD MOVE IN THE DENVER AREA AROUND 18Z. OVERALL THE DYNAMICS
ALOFT ARE FAIRLY WEAK AS THE SYSTEM SPLITS TO THE NORTH AND WEST
LATE THURSDAY AND THURSDAY NIGHT. SPATIAL CROSS-SECTIONS DO SHOW
SOME UPSLOPE DEVELOPING ALONG THE FRONT RANGE LATE THURSDAY AFTN
AND EVENING. DECENT MOISTURE AS WELL AOB 700 MB...BUT BOTH THE
UPSLOPE AND MOISTURE DECREASE FAIRLY RAPIDLY AFTER 06Z THURSDAY
NIGHT. BEST CHC OF SNOW MAY BE ALONG THE NRN BORDER WHERE LOW
LEVEL UPSLOPE AND UPPER LEVEL LIFT ASSOCIATED WITH THE JET
COINCIDE. SNOW AMOUNTS WILL BE LIGHT OVERALL BUT BRIEF ENHANCED
BANDS COULD DEVELOP IN THIS AREA. IT WILL BE MUCH COOLER ON
FRIDAY...BUT THE LOWER LEVELS APPEAR FAIRLY DRY...SO SNOW
POTENTIAL SHOULD BE DONE ACROSS THE NERN PLAINS AFTER 12Z FRIDAY.
TEMPERATURES ON FRIDAY WILL BE 25 DEGREES COOLER THAN THOSE ON
WEDNESDAY. NO TEMPERATURE RECOVERY EXPECTED ON SATURDAY AS THE
GFS DOES SHOW A SECONDARY PUSH OF COLD AIR LATE SATURDAY AFTN
ALONG WITH A BRIEF PERIOD OF UPSLOPE. THIS MAY RESULT IN A SLGT
CHC OF SNOW LATE SATURDAY AFTN/EVNG ALONG THE FRONT RANGE. THE SRN
BRANCH OF THE SPLIT TROUGH IS PROGGED TO PASS WELL SOUTH OF
COLORADO AS IT MOVES ACROSS NRN MX FRIDAY NIGHT AND INTO NCNTRL TX
BY 00Z SUNDAY. THERE WILL BE JUST A BRIEF PERIOD OF WEAK QG ASCENT
AOA 500 MB ASSOCIATED WITH THE PASSAGE OF THE NRN BRANCH OF THE
TROUGH AXIS AROUND 00Z SUNDAY...THEN IT BREAKS UP. ON SUNDAY IT
WILL REMAIN MOSTLY CLOUDY WITH MOST OF THE MOISTURE AOA 650 MB.
THE LOWER LEVELS WILL BE DRY WITH A W/NWLY DOWNSLOPE FLOW IN
PLACE. AS A RESULT...SHOULD SEE TEMPERATURES START TO MODERATE TO
NEAR SEASONAL NORMALS ON SUNDAY.
AVIATION...VFR THROUGH TONIGHT. WEST WINDS GUSTING IN THE 20 TO
30 KNOT RANGE NEAR THE FOOTHILLS...WITH WEST TO NORTHWEST WINDS
MIXING TO THE SURFACE AT KDEN/KAPA IN THE AFTERNOON WITH GUSTS
AROUND 20 KNOTS AT KDEN. DECREASING WINDS AWAY FROM THE FOOTHILLS
WITH A TREND BACK TOWARD SOUTHERLY THIS EVENING...BUT SOME
INCREASE AGAIN BY WEDNESDAY MORNING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....COOPER
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS NEW YORK NY
413 PM EST TUE DEC 17 2013
.SYNOPSIS...
WEAK LOW PRESSURE WILL PASS JUST SOUTH AND EAST OF LONG ISLAND
INTO EARLY THIS EVENING...AND THEN PULL AWAY INTO THE GULF OF
MAINE LATER TONIGHT. HIGH PRESSURE WILL THEN DOMINATE FROM
WEDNESDAY INTO THURSDAY NIGHT. A SLOW MOVING FRONTAL SYSTEM WILL
AFFECT THE AREA FRIDAY THROUGH MONDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
MID AFTERNOON MESOANALYSIS SHOWS THE WEAK LOW NOW SOUTH OF CENTRAL
LONG ISLAND AND EAST OF THE CENTRAL NJ AND EXHIBITING A DUAL
COASTAL FRONT SETUP...ONE FROM FIRE ISLAND ACROSS THE SOUTH FORK
OF LONG ISLAND...AND ANOTHER ALONG THE SE CT COAST.
FOLLOWED LATEST RAP MODEL FOR THERMAL PROFILES ALOFT BUT WITH A
LITTLE EXTRA H9 WARMING...WHICH ALONG WITH COASTAL FRONT SETUP
MEANS THAT AREAS NORTH/WEST OF NYC SHOULD REMAIN NEARLY ALL
SNOW...WITH ONLY A BRIEF WARM INTRUSION ALOFT ALONG THE CT COAST.
FROM NYC METRO EAST ACROSS MOST OF LONG ISLAND BETWEEN THE TWO
COASTAL FRONTS...WINDS ARE STARTING TO BACK WHICH WILL BRING
COLDER LOW LEVEL AIR BACK ACROSS LONG ISLAND...WITH A GRADUAL
CHANGE FROM FREEZING RAIN/SLEET IN NYC METRO BACK TO LIGHT
SNOW...AND FROM RAIN TO FREEZING RAIN AND SLEET ACROSS MOST OF
LONG ISLAND BEFORE ENDING THIS EVENING. ADVYS HAVE BEEN EXTENDED
TO THE SOUTH SHORE OF WRN LONG ISLAND FOR THE FREEZING RAIN...AND
IN TIME FOR SOUTHERN CT UNTIL 9 PM AND ELSEWHERE UNTIL 7 PM.
SNOWFALL TOTALS FOR MOST PLACES SHOULD STILL RANGE FROM 2-4
INCHES...BUT CANNOT RULE OUT SOME 5 INCH TOTALS OVER SOUTHERN CT.
ALONG THE SOUTH SHORE OF LONG ISLAND...TOTALS SHOULD BE UNDER 2
INCHES...WITH LESS THAN AN INCH ON THE SOUTH FORK.
AFTER PRECIP TAPERS OFF THIS EVENING...MOSTLY CLOUDY SKIES WILL
CONTINUE THROUGH THE NIGHT VIA CYCLONIC LOW LEVEL FLOW AND UPPER
TROUGH PASSAGE. N-NW WINDS WILL ALSO BECOME GUSTY AS THE NIGHT
PROGRESSES. LOWS WILL 20-25 IN NYC METRO AND LONG ISLAND...AND
15-20 ELSEWHERE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
HIGH PRESSURE WILL BUILD IN TO OUR SOUTH ON WED...WITH A BRISK NW
FLOW BACKING W IN THE AFTERNOON AND GUSTING TO 25-30 MPH.
SHOULD SEE SCT-BKN STRATOCU DEVELOPMENT ESPECIALLY NORTH/WEST OF
NYC. HIGHS WILL STILL BE ABOUT 5 DEG BELOW AVG...WITH MID AND
UPPER 30S.
W WINDS WILL DROP OFF WED NIGHT...WITH CLOUDS CONTINUING
ESPECIALLY INLAND AS A WARM FRONT PASSES WELL TO THE NORTH.
FCST LOWS RANGE FROM 15-20 INLAND TO THE LOWER AND MID 20S
ELSEWHERE. WITH CLOUD COVER AND W FLOW STILL 25 KT JUST OFF THE
DECK DO NOT EXPECT THE BOTTOM TO FALL OUT ON INLAND TEMPS VIA
RADIATIONAL COOLING DESPITE DIMINISHING WINDS AND SNOW PACK.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
FORECAST MODELS CONTINUE TO SHOW GOOD AGREEMENT IN THE OVERALL
SYNOPTIC PATTERN THROUGH THIS PERIOD. WE START THE LONG TERM PERIOD
WITH FAIRLY ZONAL FLOW ALOFT ACROSS THE COUNTRY WITH SURFACE HIGH
PRESSURE ANCHORED OFF THE SOUTHEASTERN COAST. THIS WILL RESULT IN A
MILDER RETURN FLOW UP THE EASTERN SEABOARD...ALLOWING TEMPERATURES
TO REBOUND TO NEAR SEASONAL NORMALS ON THURSDAY BEFORE SETTING US UP
FOR A VERY MILD WEEKEND.
AT THE SURFACE...A SLOW MOVING FRONTAL SYSTEM WILL APPROACH FROM
THE WEST ON FRIDAY THROUGH THE WEEKEND WITH SEVERAL WAVES OF LOW
PRESSURE RIDING ALONG IT. EXPECT ON AND OFF SHOWER ACTIVITY
FROM FRIDAY INTO MONDAY AND POSSIBLY MONDAY EVENING. HOWEVER...WITH
THE SLOW EASTWARD PROGRESSION OF THE FRONT...THE WAVES THAT DEVELOP
AND MOVE ALONG IT WILL REMAIN WELL TO OUR WEST UNTIL SUNDAY NIGHT.
THIS WILL KEEP THE MOST SIGNIFICANT RAINFALL WEST OF THE AREA. THE
FRONT WILL EVENTUALLY PUSH EASTWARD...SLOWLY MOVING ACROSS THE AREA
MONDAY INTO MONDAY EVENING. DO NOT EXPECT ANY ISSUES WITH
PRECIPITATION TYPE UNTIL THE VERY TAIL END OF THINGS LATE MONDAY OR
MONDAY NIGHT AS WE REMAIN IN THE WARM SECTOR THROUGHOUT. THE COLD
AIR PUSHES IN JUST ABOUT THE TIME PRECIPITATION SHUTS OFF...SO WILL
KEEP THE CHANCE OF SNOW TO THE NORTH AND WEST OF NEW YORK CITY AND
THE I-95 CORRIDOR AT THIS TIME.
TEMPERATURES WILL TREND MILDER AND WILL CLIMB ABOVE SEASONAL NORMALS
BY THE END OF THE WEEK. SHAVED A FEW DEGREES OFF GUIDANCE FOR THE
WEEKEND MAXIMUMS...ESPECIALLY FOR AREAS WITH A MARINE FETCH AS WATER
TEMPERATURES IN THE 40S AND PLENTY OF CLOUD COVER WILL MAKE IT
DIFFICULT FOR TEMPERATURES TO CLIMB MUCH ABOVE 55-60. THEN A
SIGNIFICANT CHANGE IN AIR MASS WILL OCCUR ONCE THE NEXT COLD FRONT
PUSHES THROUGH EARLY NEXT WEEK. THIS WILL SEND TEMPERATURES DOWN
BELOW NORMAL INTO THE MIDDLE OF NEXT WEEK.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
WEAK LOW PRESSURE CENTER JUST SOUTH OF THE TERMINALS LATE THIS
AFTERNOON SHIFTS EAST INTO EARLY EVENING..
MODERATE TO HIGH CONFIDENCE IN WINDS. GENERALLY N TO NNW AROUND 10
KT INTO THIS EVENING.
MODERATE CONFIDENCE IN VSBYS/CIGS...MAINLY IFR TO MVFR INTO EARLY
EVENING...EVENTUALLY IMPROVING TO VFR BY MIDNIGHT.
MODERATE CONFIDENCE IN PCPN TYPE. SHOULD BE MIXED FOR ALL BUT KSWF.
VERY LITTLE TO NO ADDITIONAL SNOW/SLEET ACCUMULATIONS FROM THIS
POINT ON. PCPN SHOULD END 22-00Z FOR MOST SPOTS.
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: -SNPL OR -SN MIGHT PREVAIL THROUGH 22Z.
KJFK FCSTER COMMENTS: RA INSTEAD OF FZRA COULD OCCUR THROUGH 2230Z.
TEMPO -FZRAPL MIGHT NOT OCCUR. -SN COULD ALSO BE MIXED IN AT TIMES
AFTER 2130Z.
KLGA FCSTER COMMENTS: -SNPL COULD POSSIBLY PREVAIL THROUGH 2230Z
KTEB FCSTER COMMENTS: -SNPL OR -SN MIGHT PREVAIL THROUGH 22Z.
KHPN FCSTER COMMENTS: -SN COULD PREVAIL THROUGH 2230Z.
KISP FCSTER COMMENTS: -SN COULD BE MIXED IN AFTER 23Z.
.OUTLOOK FOR 18Z WEDNESDAY THROUGH SATURDAY...
.WED...VFR. WNW GUSTS 20-25KT
.THU...VFR.
.FRI...MVFR OR LOWER POSSIBLE WITH CHC RAIN OVERNIGHT.
.SAT...MVFR OR LOWER WITH SHRA
.SUN...MVFR OR LOWER WITH SHRA. CHC SW GUSTS 25-30KT AND LLWS.
&&
.MARINE...
SMALL CRAFT ADVISORY CONDITIONS CONTINUE LATE THIS AFTERNOON ON
THE OCEAN AND ERN SOUND/BAYS. SMALL CRAFT ADVISORY CONDITIONS ARE
EXPECTED TO CONTINUE ACROSS OCEAN WATERS LATER TONIGHT INTO WED
NIGHT ON GUSTY W-NW FLOW.
SCA WINDS AND SEAS ARE ALSO LIKELY FRIDAY THROUGH THE WEEKEND
FROM A PROLONGED PERIOD OF SOUTH TO SOUTHWESTERLY FLOW AHEAD OF A
SLOW MOVING FRONTAL SYSTEM.
&&
.HYDROLOGY...
LOW PRESSURE PASSING SOUTH OF LONG ISLAND WILL BRING 1/3 TO 1/2
INCH LIQUID EQUIVALENT QPF. MOST OF THIS SHOULD BE IN THE FORM OF
SNOW...WITH 1-5 INCHES ACCUMULATION...HIGHEST OVER SOUTHERN CT.
&&
.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...WINTER WEATHER ADVISORY UNTIL 9 PM EST THIS EVENING FOR
CTZ005>012.
NY...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
NYZ067>075-078>080-176>179.
NJ...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NJZ002-
004-006-103>108.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ330-
340.
SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ350-353-
355.
&&
$$
SYNOPSIS...GOODMAN
NEAR TERM...GOODMAN
SHORT TERM...GOODMAN
LONG TERM...
AVIATION...JC
MARINE...GOODMAN
HYDROLOGY...JC
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS ALBANY NY
1240 PM EST TUE DEC 17 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM PASSING SOUTH OF THE REGION WILL BRING A
WIDESPREAD LIGHT TO MODERATE SNOWFALL TO THE AREA TODAY. THE SNOW
WILL SPREAD NORTHWARD ACROSS THE AREA DURING THIS MORNING AND IS
EXPECTED TO TAPER OFF THIS EVENING. SCATTERED SNOW SHOWERS ARE
THEN EXPECTED TONIGHT AND WEDNESDAY...ESPECIALLY ACROSS THE HIGHER
TERRAIN. A GRADUAL WARMING TREND IS THEN EXPECTED FOR THE END OF
THE WORKWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1240 PM EST...THE WINTER WX ADVISORY CONTINUES FROM THE
CAPITAL REGION...MOHAWK VALLEY...SRN VT SOUTHWARD UNTIL 7 PM. A
LULL IN THE PCPN HAS OCCURRED OVER THE CAPITAL REGION...CNTRL
TACONICS...AND BERKSHIRES...BUT THE PCPN IS FILLING BACK IN
QUICKLY OVER THE ERN CATSKILLS...MID HUDSON VALLEY...AND NW
CT...AS THE NEW LOW PRESSURE SYSTEM FORMS E/SE OF KACY. PRESSURE
FALLS OF 3-5 HPA/3 HRS ARE OCCURRING JUST NORTHEAST OF THE LOW
OVER SOUTHERN LONG ISLAND. THE CYCLONE SHOULD QUICKLY TRACK
NORTHEAST THIS PM.
SNOWFALL TOTAL POTENTIAL OF 2 TO 6 INCHES CONTINUES FOR THE PM.
THE HIGHER AMOUNTS OVER THE HIGHER TERRAIN...BASED ON THE 12Z
NAM...AND RUC TRENDS /FAVORS WRN NEW ENGLAND/. EXPECTING SNOW TO
LIQUID RATIOS OF 15-20:1 TO ACCOUNT FOR TOTALS TO GET INTO THE
ADVISORY RANGE.
THE 850-700HPA 2D FGEN BASED ON THE 12Z 40-KM NAM SHOWS A DECENT
RIBBON EXTENDING UP TO THE CAPITAL REGION AND DIPPING SOUTH AND
EAST. HENCE...AN ADDITIONAL 1 TO 4 INCHES OF SNOW MAY BE POSSIBLE.
SNOW TOTALS SO FAR HAVE RANGED FROM A HALF AN INCH TO TWO INCHES BASED
ON OUR LATEST PNS.
TEMPS TODAY WILL STRUGGLE TO CLIMB INTO AND THROUGH THE TEENS TO
LOWER 20S IN VALLEY AREAS...AND LOWER TO MID TEENS ACROSS HIGHER
ELEVATIONS...WITH MAX TEMPS LIKELY NOT OCCURRING UNTIL BETWEEN 5-7
PM. GIVEN THAT THE CLOUDS WILL BE RATHER LOW...AND THAT MUCH OF
THE PRECIP WILL BE FALLING FROM A LOWER CLOUD DECK INITIALLY THEN
WHAT OCCURRED ON SATURDAY...THE POTENTIAL AND DEPTH OF WET BULB
COOLING WILL BE LESS THAN WHAT OCCURRED THIS PAST SAT. SO...WE
HAVE SIDED WITH THE COOLER SIDE OF A MAV/MET MOS BLEND...BUT DID
NOT STRAY TOO MUCH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
TONIGHT...ANY STEADIER SNOW SHOULD TAPER OFF ACROSS SE VT EARLY.
OTHERWISE...EXPECT SCATTERED SNOW SHOWERS TO OCCUR OVERNIGHT AS
THE MID/UPPER LEVEL TROPOSPHERIC TROUGH AND COLD POOL PASS
THROUGH...WITH 500 MB TEMPS DIPPING INTO THE -35C TO -40C RANGE.
925-700 LAPSE RATES STEEPEN...AND SHOULD ENOUGH MOISTURE BE
PRESENT WITHIN THIS LAYER...COULD LEAD TO SOME EMBEDDED HEAVIER SNOW
SHOWERS AND/OR SQUALLS...LEAVING ADDITIONAL COATINGS...TO PERHAPS
UP TO AN INCH OF SNOWFALL OVERNIGHT. TEMPS SHOULD FALL INTO THE
TEENS IN MOST AREAS.
WED-WED NT...THE AFOREMENTIONED MID LEVEL TROUGH/COLD POOL MOVES E
OF THE REGION IN THE AFTERNOON. HOWEVER...A FAIRLY WELL ALIGNED
WESTERLY FLOW MAY ALLOW FOR LAKE EFFECT SNOWBANDS TO DEVELOP
ACROSS NORTHERN HERKIMER CO IN THE AFTERNOON...AND MAY EXTEND WELL
INTO HAMILTON CO OR EVEN NW WARREN CO FOR A BRIEF TIME LATE IN THE
AFTERNOON INTO EARLY WED NT...AS SUGGESTED PER THE CSTAR FUNDED
INLAND LAKE EXTENT PROGRAM. THIS COULD LEAD TO AT LEAST 1-3 INCHES
OF SNOWFALL...WITH SOME POTENTIAL FOR GREATER AMTS...PERHAPS INTO
THE ADVISORY RANGE. WILL ADDRESS THIS POTENTIAL IN THE HWOALY.
ELSEWHERE...SCATTERED SNOW SHOWERS AND FLURRIES WILL BE POSSIBLE
ACROSS HIGHER ELEVATIONS...WHERE ADDITIONAL MINOR ACCUMS COULD
OCCUR...WITH SOME SNOW SHOWERS/FLURRIES OCCASIONALLY MIGRATING
INTO VALLEY AREAS...ESP NEAR AND N OF THE MOHAWK RIVER. FOR
TEMPS...EXPECT SLIGHTLY MILDER MAX TEMPS WED...REACHING THE 20S TO
LOWER 30S IN VALLEYS...WITH TEENS TO MID 20S ACROSS HIGHER
ELEVATIONS...AND OVERNIGHT MINS WED NT/THU AM FALLING MAINLY INTO
THE TEENS...WITH SOME SINGLE DIGITS POSSIBLE ACROSS NORTHERN AREAS
AND HIGHER ELEVATIONS ACROSS WESTERN NEW ENGLAND.
THU-THU NT...A SOUTHWEST LOW LEVEL FLOW WILL DEVELOP DURING THIS
TIME...ALLOWING FOR GRADUAL MODERATION IN TEMPS. SOME LINGERING
LAKE EFFECT SNOW MAY OCCUR THU ACROSS EXTREME NORTHERN
HERKIMER/HAMILTON COS...BEFORE THE INVERSION LEVEL FALLS.
THEN...SOME WARM ADVECTION PRECIP COULD DEVELOP ACROSS THE WESTERN
DACKS LATE THU NT...IN THE FORM OF LIGHT SNOW...OR EVEN A LIGHT
WINTRY MIX. THU MAX TEMPS SHOULD REACH THE LOWER/MID 30S IN
VALLEYS...AND 20S ACROSS HIGHER ELEVATIONS...WITH OVERNIGHT MINS
THU NT/FRI AM ONLY FALLING INTO THE 20S IN MOST AREAS...WITH TEMPS
POSSIBLY RISING IN SOME AREAS LATE AT NIGHT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
INCREASING AGREEMENT IN THE MODEL AND ENSEMBLE GUIDANCE THROUGH THE
PERIOD. ONE UPPER IMPULSE AND ASSOCIATED FORCING SUPPORTS
PRECIPITATION FRIDAY AND FRIDAY NIGHT. THEN ANOTHER UPPER IMPULSE
AND ASSOCIATED FORCING AFFECTS OUR REGION SATURDAY NIGHT THROUGH
SUNDAY NIGHT. THE TIMING OF THESE SYSTEMS WILL LIKELY GET ADJUSTED
WITH TIME AS THEY ARE WITHIN QUICK WEST SOUTHWEST UPPER CONFLUENT
STEERING FLOW. ALSO...WORDING RAIN AND SNOW THROUGH THE PERIOD SINCE
THERE IS SUCH HIGH UNCERTAINTY IN THE POTENTIAL AREAS OF SLEET
AND/OR FREEZING RAIN.
THE PRECIPITATION TYPES AND THE POSITION OF A POTENTIALLY BROAD
PRECIPITATION TRANSITION ZONE ARE STILL IN QUESTION. HOWEVER...
THERE IS MORE AGREEMENT FOR ANY MIXED PRECIPITATION EARLY FRIDAY
MORNING TO CHANGE TO MAINLY LIQUID PRECIPITATION OVER CENTRAL AND
SOUTHERN AREAS BEFORE COVERAGE OF PRECIPITATION DECREASES FRIDAY
NIGHT. MIXED PRECIPITATION COULD REMAIN MIXED OVER NORTHERN AREAS.
HIGHS FRIDAY IN THE LOWER TO MID 40S IN MANY AREAS WITH MID TO UPPER
30S IN THE HIGHER ELEVATIONS.
LOW LEVEL FORCING WEAKENS FRIDAY NIGHT AND SATURDAY WITH WEAK LOW
LEVEL RIDGING OVER THE REGION. LINGERING MOISTURE AND PROXIMITY TO
THE LOW LEVEL THERMAL GRADIENT AND WIND CONVERGENCE PROXIMATE TO THE
LOW LEVEL BOUNDARY COULD SUPPORT SCATTERED SHOWERS...WITH SOME
FLURRIES OR SNOW SHOWERS. THE BRIEF LOW LEVEL RIDGING COULD ALLOW
TEMPERATURES TO FALL TO NEAR FREEZING IN MANY AREAS FRIDAY NIGHT AND
MID TO UPPER 20S IN THE HIGHER ELEVATIONS... AGAIN SUPPORTING
SCATTERED SHOWERS AND SNOW SHOWERS.
CURRENT GUIDANCE SUGGESTS THE NEXT SYSTEM ARRIVES THROUGH THE DAY
SATURDAY AN CONTINUES SATURDAY NIGHT THROUGH SUNDAY...EXITING SUNDAY
NIGHT. THE WARM ADVECTION AND FORCING LOOK STRONGER WITH THIS
SYSTEM...DRIVING THE WARM AIR FURTHER NORTH...SUPPORTING A
PRECIPITATION TRANSITION TO RAIN IN MOST AREAS. QUITE A STRONG
SOUTHWEST TO WEST SOUTHWEST BOUNDARY LAYER JET TRACKS THROUGH THE
REGION AND THE BOUNDARY LAYER THERMAL GRADIENT IS QUITE TIGHT AS IT
TRACKS EAST AND SOUTH SUNDAY AND SUNDAY NIGHT. SO...WILL HAVE TO
KEEP AN EYE ON WINDS AND POTENTIAL FOR LOCALLY HEAVY RAIN ON THE
MELTING SNOW PACK. HIGHS SATURDAY IN THE LOWER TO MID 40S...LOWER
TO MID 30S HIGHER ELEVATIONS. HIGHS SUNDAY IN THE UPPER 40S TO LOWER
50S...WITH UPPER 30S TO LOWER 40S IN HIGHER ELEVATIONS.
STRONG COLD ADVECTION SPREADS ACROSS THE REGION BY MONDAY MORNING
AND CONTINUES THROUGH THE DAY. SOME LAKE EFFECT SNOW BANDS SHOULD
FORM BUT INLAND EXTENT IS IN QUESTION. HIGHS MONDAY IN THE 20S TO
LOWER 30S.
THERE COULD STILL BE A LOT OF CHANGES TO HOW THESE SYSTEMS DEVELOP
AND IMPACT THE REGION. THERE ARE INDICATIONS OF A POTENTIAL BROAD
MIXED PRECIPITATION TRANSITION ZONE...BUT THE POSITION AND AREAL
EXTENT OF THE PRECIPITATION TRANSITION ZONE KEEPS CHANGING IN
SUCCESSIVE SETS OF GUIDANCE. THERE IS STILL A CHANCE THAT THE
CURRENT INDICATIONS OF MORE RAIN AND LESS WINTERY PRECIPITATION OVER
MUCH OF OUR REGION COULD CHANGE BACK TO COLDER AND MORE MIXED
PRECIPITATION DEPENDING ON HOW THE SYSTEMS DEVELOP IN THE NEXT 3+
DAYS. HOWEVER...THE INCREASING CONSENSUS FROM GUIDANCE OF MORE
LIQUID AND LESS MIXED PRECIPITATION SEEMS THE MOST LIKELY SCENARIO
AT THIS TIME.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
COASTAL WAVE WAS TAKING SHAPE AS ANY BRIEF LULL IN THE SNOW IS
EXPECTED TO FULL BACK IN THIS AFTERNOON. THIS WILL KEEP FLIGHT
CONDITIONS WITHIN MVFR AND TEMPORARILY IFR CONDITIONS AS THESE BANDS
OF MODERATE SNOWFALL DEVELOP AND IMPACT THE TAF SITES. PER THE
LATEST GUIDANCE AND UPSTREAM INFORMATION...SEEMS THIS SNOW WILL EXIT
THE REGION BY EARLY THIS EVENING WITH IMPROVEMENTS.
HOWEVER...FLIGHT CONDITIONS WILL REMAIN WITHIN MVFR THRESHOLDS WITH
SOME IFR EXPECTED AT KPOU OVERNIGHT.
WINDS ARE EXPECTED TO REMAIN RATHER LIGHT WITH A GENERALLY NORTH
DIRECTION. THE MAGNITUDES ARE EXPECTED TO DIMINISH FURTHER THIS
EVENING WITH A WEST-NORTHWEST DIRECTION DEVELOPING THROUGH
WEDNESDAY.
OUTLOOK...
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. SCATTERED SHRA...SHSN.
SATURDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF RA...SN.
&&
.HYDROLOGY...
A CLIPPER TYPE SYSTEM WILL AFFECT THE REGION TODAY INTO THIS
EVENING. THE PRECIPITATION IS EXPECTED TO BE ALL SNOW WITH THIS
SYSTEM. TOTAL LIQUID EQUIVALENT WITH THIS SYSTEM IS EXPECTED TO
RANGE FROM ONE TO THREE TENTHS OF AN INCH WITH THE HIGHEST AMOUNTS
OVER THE ERN CATSKILLS...W-CNTRL MOHAWK VALLEY...AND WRN NEW
ENGLAND. THIS SYSTEM WILL REDEVELOP SOUTH OF LONG ISLAND...AND
QUICKLY MOVE NORTHEAST OF CAPE COD TOMORROW NIGHT.
SOME LAKE EFFECT SNOW IS POSSIBLE WED-THU WITH LIGHT SNOW
AMOUNTS...AND LIQUID EQUIVALENTS GENERALLY LESS THAN A TENTH OF AN
INCH FOR THE WRN DACKS REGION...AND NRN TIER OF THE HSA.
FOR THE MID WEEK...TEMPS WILL CONTINUE TO BE BELOW NORMAL AND ICE
WILL CONTINUE TO FORM AND THICKEN ON AREA RIVERS...STREAMS AND
PARTICULARLY LAKES.
A MODERATING TREND IN TEMPS IS LIKELY THU INTO FRI...WITH A
FRONTAL BOUNDARY BRINGING SOME SHOWERS TO CLOSE THE WORK WEEK.
SOME SNOW MELT IS LIKELY THIS WEEKEND. ALSO...A STORM SYSTEM
MOVING ALONG A FRONTAL BOUNDARY NEAR THE HSA MAY BRING SIGNIFICANT
PCPN TO THE FORECAST AREA SAT NIGHT INTO SUNDAY WITH EVEN MILDER
TEMPS. THIS WILL CONTINUE TO BE MONITORED FOR THE UPCOMING
WEEKEND.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR CTZ001-
013.
NY...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
NYZ038>040-047>054-058>061-063>066-082.
MA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MAZ001-
025.
VT...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
VTZ013>015.
&&
$$
SYNOPSIS...KL/WASULA
NEAR TERM...KL/BGM/WASULA
SHORT TERM...KL
LONG TERM...NAS
AVIATION...BGM
HYDROLOGY...KL/WASULA
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1245 PM EST TUE DEC 17 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHERN STATES WILL SLIP WESTWARD THIS
AFTERNOON ALLOWING A MOISTURE STARVED COLD FRONT TO CROSS OUR AREA
THIS EVENING. HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY
THEN SLIDE OFF THE SOUTHEAST COAST THURSDAY. A SOUTHERLY FLOW WILL
BRING MUCH ABOVE NORMAL TEMPERATURES TO THE AREA FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE STRETCHED ACROSS THE GULF COAST STATES THIS
AFTERNOON WITH A COLD FRONT EXTENDING FROM PA THROUGH KY TO AR.
OUR AIR MASS REMAINED DRY WITH PWAT LESS THAN 0.50 INCHES. STILL
EXPECT CLEAR SKIES TO HOLD ACROSS THE AREA. THE FRONT WILL MOVE
THROUGH THE FORECAST AREA EARLY TONIGHT.
IT WILL BE WARM AND BREEZY AHEAD OF THE FRONT THIS AFTERNOON. THE
NAM BUFKIT MOMENTUM TRANSFER TOOL SUPPORTS GUSTS AROUND 20 KNOTS.
THE 10Z HRRR INDICATES GUSTS OF 20 TO 25 KNOTS. LEANED TOWARD THE
WARMER TEMPERATURE GUIDANCE THIS AFTERNOON GIVEN DRY AIR MASS AND
WARMING JUST AHEAD OF THE COLD FRONT. KEPT HIGHS IN THE LOW/MID
60S. THERE WILL BE MIXING FOR MUCH OF TONIGHT WHICH SHOULD HELP
HOLD UP TEMPERATURES. HOWEVER...THE GRADIENT SHOULD RELAX TOWARD
SUNRISE. USED THE GUIDANCE CONSENSUS FOR THE LOW TEMPERATURE
FORECAST IN THE LOW/MID 30S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BE MOVING INTO THE FORECAST AREA FROM THE WEST
WEDNESDAY. EXPECT CLEAR SKIES. THE TEMPERATURE GUIDANCE WAS
CONSISTENT. THE HIGH WILL BE CENTERED OVER THE AREA WEDNESDAY
NIGHT. THERE MAY BE SOME HIGH CLOUDINESS AS THE UPPER RIDGE
FLATTENS BUT EXPECT THIS CLOUDINESS WILL BE THIN AND STRONG NET
RADIATIONAL COOLING SHOULD OCCUR. WE LEANED TOWARD THE COOLER
TEMPERATURE GUIDANCE. WARMING SHOULD BEGIN THURSDAY AS THE HIGH
SHIFTS OFF THE COAST AND A SOUTHERLY FLOW DEVELOPS. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
RETURN FLOW ON THE WEST SIDE OF HIGH PRESSURE OFF THE SOUTHEAST
COAST WILL BRING INCREASING MOISTURE AND WARMER TEMPERATURES TO
THE AREA INTO THE WEEKEND. RAPIDLY INCREASING MOISTURE WILL LIKELY
RESULT LOW MORNING STRATUS FRIDAY AND SATURDAY. TEMPERATURES WILL
INCREASE TO MUCH ABOVE NORMAL BY SUNDAY WITH MORNING LOWS NEAR 60
AND HIGHS IN THE MID TO UPPER 70S. A COLD FRONT WILL APPROACH THE
AREA FROM THE WEST ON SUNDAY AND CROSS THE AREA SUNDAY NIGHT INTO
MONDAY. WILL INCREASE POPS TO THE 60 TO 70 PERCENT RANGE WITH THE
FRONTAL PASSAGE. WITH WARM MOIST AIR AT LOW LEVELS...A 40 TO 50 KT
LOW LEVEL JET...AND SLIGHTLY UNSTABLE LI VALUES...SOME CONVECTION
IS POSSIBLE WITH THIS FRONTAL PASSAGE. WILL HAVE TO WATCH THIS AS
WE GET CLOSER TO THE EVENT. DRIER AND COLDER AIR WILL MOVE IN
BEHIND THE FRONT MONDAY AFTERNOON INTO TUESDAY.
WHILE THE TREND FOR INCREASING TEMPERATURES AND DEWPOINTS IS HIGH
CONFIDENCE...THE DETAILS ARE TOUGH TO NAIL DOWN DUE TO THE
POTENTIAL FOR MORNING STRATUS ON FRIDAY AND SATURDAY. CONFIDENCE
FOR RAIN WITH THE FRONTAL PASSAGE IS ABOVE AVERAGE.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE FORECAST PERIOD.
DRY AIR MASS IN PLACE FOR CLEAR SKIES. WEST TO SOUTHWEST WINDS
AROUND 10 KNOTS WITH GUST UP TO 20 KNOTS THIS AFTERNOON.
WINDS SHOULD DECREASE BY SUNSET THEN VEER WEST TO NORTHWEST THIS
EVENING AS A COLD FRONT MOVES THROUGH THE TAF SITES.
EXTENDED AVIATION OUTLOOK...INCREASING LOW LEVEL MOISTURE COMBINED
WITH NOCTURNAL COOLING COULD ALLOW MVFR/IFR CIGS/FOG TO DEVELOP
DURING THE LATE NIGHT AND EARLY MORNING HOURS FRIDAY THROUGH SUNDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1242 PM EST TUE DEC 17 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHERN STATES WILL SLIP WESTWARD THIS
AFTERNOON ALLOWING A MOISTURE STARVED COLD FRONT TO CROSS OUR AREA
THIS EVENING. HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY
THEN SLIDE OFF THE SOUTHEAST COAST THURSDAY. A SOUTHERLY FLOW WILL
BRING MUCH ABOVE NORMAL TEMPERATURES TO THE AREA FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE STRETCHED ACROSS THE GULF COAST STATES LATE THIS
MORNING WITH A COLD FRONT EXTENDING FROM PA THROUGH KY TO AR. OUR
AIR MASS REMAINED DRY WITH PWAT LESS THAN 0.50 INCHES. STILL
EXPECT CLEAR SKIES TO HOLD ACROSS THE AREA. THE FRONT WILL MOVE
THROUGH THE FORECAST AREA EARLY TONIGHT.
IT WILL BE WARM AND BREEZY AHEAD OF THE FRONT THIS AFTERNOON. THE
NAM BUFKIT MOMENTUM TRANSFER TOOL SUPPORTS GUSTS AROUND 20 KNOTS.
THE 10Z HRRR INDICATES GUSTS OF 20 TO 25 KNOTS. LEANED TOWARD THE
WARMER TEMPERATURE GUIDANCE THIS AFTERNOON GIVEN DRY AIR MASS AND
WARMING JUST AHEAD OF THE COLD FRONT. KEPT HIGHS IN THE LOW/MID
60S. THERE WILL BE MIXING FOR MUCH OF TONIGHT WHICH SHOULD HELP
HOLD UP TEMPERATURES. HOWEVER... THE GRADIENT SHOULD RELAX TOWARD
SUNRISE. USED THE GUIDANCE CONSENSUS FOR THE LOW TEMPERATURE
FORECAST IN THE LOW/MID 30S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BE MOVING INTO THE FORECAST AREA FROM THE WEST
WEDNESDAY. EXPECT CLEAR SKIES. THE TEMPERATURE GUIDANCE WAS
CONSISTENT. THE HIGH WILL BE CENTERED OVER THE AREA WEDNESDAY
NIGHT. THERE MAY BE SOME HIGH CLOUDINESS AS THE UPPER RIDGE
FLATTENS BUT EXPECT THIS CLOUDINESS WILL BE THIN AND STRONG NET
RADIATIONAL COOLING SHOULD OCCUR. WE LEANED TOWARD THE COOLER
TEMPERATURE GUIDANCE. WARMING SHOULD BEGIN THURSDAY AS THE HIGH
SHIFTS OFF THE COAST AND A SOUTHERLY FLOW DEVELOPS. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
RETURN FLOW ON THE WEST SIDE OF HIGH PRESSURE OFF THE SOUTHEAST
COAST WILL BRING INCREASING MOISTURE AND WARMER TEMPERATURES TO
THE AREA INTO THE WEEKEND. RAPIDLY INCREASING MOISTURE WILL LIKELY
RESULT LOW MORNING STRATUS FRIDAY AND SATURDAY. TEMPERATURES WILL
INCREASE TO MUCH ABOVE NORMAL BY SUNDAY WITH MORNING LOWS NEAR 60
AND HIGHS IN THE MID TO UPPER 70S. A COLD FRONT WILL APPROACH THE
AREA FROM THE WEST ON SUNDAY AND CROSS THE AREA SUNDAY NIGHT INTO
MONDAY. WILL INCREASE POPS TO THE 60 TO 70 PERCENT RANGE WITH THE
FRONTAL PASSAGE. WITH WARM MOIST AIR AT LOW LEVELS...A 40 TO 50 KT
LOW LEVEL JET...AND SLIGHTLY UNSTABLE LI VALUES...SOME CONVECTION
IS POSSIBLE WITH THIS FRONTAL PASSAGE. WILL HAVE TO WATCH THIS AS
WE GET CLOSER TO THE EVENT. DRIER AND COLDER AIR WILL MOVE IN
BEHIND THE FRONT MONDAY AFTERNOON INTO TUESDAY.
WHILE THE TREND FOR INCREASING TEMPERATURES AND DEWPOINTS IS HIGH
CONFIDENCE...THE DETAILS ARE TOUGH TO NAIL DOWN DUE TO THE
POTENTIAL FOR MORNING STRATUS ON FRIDAY AND SATURDAY. CONFIDENCE
FOR RAIN WITH THE FRONTAL PASSAGE IS ABOVE AVERAGE.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE FORECAST PERIOD.
DRY AIR MASS IN PLACE FOR CLEAR SKIES. WINDS BEGINNING TO
INCREASE AT 15Z AS STRONGER WINDS ALOFT MIX DOWN TO THE SURFACE
AHEAD OF AN APPROACHING FRONT. SOME OF THE STRONGER GUSTS MAY
REACH 20 KNOTS LATE THIS MORNING INTO THE AFTERNOON. SOUTHWEST
WINDS THIS AFTERNOON WILL DECREASE BEFORE SHIFTING WEST 18/01Z
THROUGH 18/03Z AS A COLD FRONT MOVES THROUGH THE TAF SITES.
EXTENDED AVIATION OUTLOOK...IFR/MVFR CONDITIONS IN LOW STRATUS
POSSIBLE FRIDAY...SATURDAY...AND SUNDAY MORNINGS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
319 PM CST TUE DEC 17 2013
.DISCUSSION...
328 AM CST
TODAY...
MAIN CONCERNS WILL BE FOCUSED ON THE MID-LVL WAVE THAT IS QUICKLY
SLIDING EAST ACROSS THE WESTERN GREAT LAKES...POSSIBLY BRINGING A
SLUG OF LGT SNOW TO NORTH/NORTHEAST IL AND NORTHWEST IN THIS MORNING
THRU MIDDAY. THEN THE POTENTIAL FOR SOME BLOWING SNOW AS THE
GRADIENT RAMPS UP MIDDAY AND MIXING JUMPS TO ARND 3KFT AGL.
IR IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS THE REGION...AND
SOME COOLING WITH CLOUD TOPS WITH THE WEAK WAVE SLIDING EAST ACROSS
WESTCENTRAL WISC EARLY THIS MORNING. KARX RADAR INDICATES AN AREA OF
RETURNS ACROSS THIS AREA...HOWEVER THE RECENT COUPLE OF HOURS HAVE
INDICATED SOME DOWNWARD TREND IN THE SOUTHERN PORTION OF THIS
PRECIP. SFC OBS ARE NOT INDICATING ANY SNOW IN FAR SOUTHEAST MN AND
HAS TENDED TO BE FOCUSED FURTHER NORTH. BASED ON CURRENT
TRAJECTORY...THE BEST LGT SNOW MAY END UP HOLDING FURTHER NORTH INTO
WISC. BUFR PROFILES HAVE BACKED OFF ON THE OMEGA PLACEMENT...HOWEVER
A HANDFUL OF POINTS CONTINUE TO INDICATE SOME DEGREE OF LIFT THROUGH
THE FAVORED DGZ ARND 12-15Z. DPROG/DT OF THE BUFR SITES ALSO
INDICATES A DOWNWARD TREND...SUPPORTING THE LOWER CONFIDENCE IN SNOW
TOTALS. THE CAVEAT AND CHALLENGE IS THE NARROW CHANNEL OF MOISTURE
THAT STRETCHES WEST AND RECENT RAP GUIDANCE HAS INDICATED AN
ENHANCEMENT TO THIS FEATURE AS IT PIVOTS EAST ACROSS THE CWFA THIS
MORNING.
SNOWFALL RATIOS SHOULD FALL AROUND 20:1...SO RATHER DRY.
BASED ON COBB OUTPUT FROM THESE PROFILES SNOWFALL SHUD GENERALLY
FALL BETWEEN A FEW TENTHS TO 1". COULD SEE AREAS CLOSEST TO THE
WISCONSIN STATELINE PICKING UP SLIGHTLY MORE OR WITHIN A 1-2" RANGE.
THE WAVE WILL REMAIN PROGRESSIVE AND SHUD COME TO AN END BY 15-17Z
FROM WEST TO EAST...AS WIND GUSTS BEGIN TO DEVELOP. ANY FRESH
SNOWFALL SHUD EASILY BLOW AROUND. THIS MAY BE MORE FOCUSED ACROSS
AREAS NORTH OF I-80...AS THE PATCHY DZ EARLY THIS MORNING WILL
MOISTEN UP THE SNOW FURTHER SOUTH AND LIMIT THE ABILITY FOR THE SNOW
TO BLOW AROUND.
TEMPS WILL BEGIN TO REBOUND TDY...AS THE 500MB TROUGH AXIS BEGINS TO
PUSH EAST OF THE WESTERN GREAT LAKES. TEMPS WILL STEADILY WARM INTO
THE UPR 20S TO ARND 30 ACROSS THE SOUTHERN CWFA.
CONFIDENCE IN SNOWFALL...MEDIUM/LOW.
CONFIDENCE IN TEMPS...HIGH.
TONIGHT THROUGH WEDNESDAY...
500MB HEIGHTS BEGIN TO RISE THIS EVENING WITH DIFFLUENT FLOW LIFTING
NORTH FROM THE SFC RIDGE CENTERED ACROSS THE OZARKS. THIS SHUD AID
IN ERODING SOME OF THE CLOUD COVER...AND COULD SEE P-CLOUDY SKIES
FOR A BRIEF PERIOD OVERNIGHT. THEN ANOTHER WEAK MID-LVL WAVE IS
PROGGED TO BUMP INTO THE DIFFLUENT FLOW AND BRING SOME MID-LVL
MOISTURE AND CLOUDS BACK TO THE AREA DURING THE OVERNIGHT HOURS.
500MB FLOW CONTINUES TO EVOLVE INTO A ZONAL SETUP...ALTHOUGH THIS
WILL ONLY BE TEMPORARY THRU WED. SFC RIDGE ACROSS THE OZARKS DRIFTS
EAST TOWARDS THE MID-ATLANTIC/GULF STATES...WITH LLVL FLOW TURNING
SOUTH/SOUTHWEST FOR THE CWFA.
FOR THE FIRST TIME IN SEVERAL DAYS WED MAY SEE THE 850MB 0 DEG
ISOTHERM LIFT OVERHEAD ALONG THE LEADING EDGE OF INCREASED WARM AIR
ADVECTION. THE MID-LVL THERMAL RIDGE CONTINUES TO WARM FURTHER SOUTH
WITH TEMPS RISING TO NEAR 9 DEG C OVER NORTHERN MISSOURI WED AFTN.
GIVEN THE EXPANSIVE SNOW COVER...THE CHALLENGE IS HOW WARM WILL WED
END UP BECOMING. GUIDANCE HAS TRENDED SLIGHTLY COOLER OVER THE PAST
FEW DAYS WITH WED HIGHS. AT THIS TIME THE GENERAL CONSENSUS HAS BEEN
ON TEMPS IN THE LOW 30S ALONG/NORTH OF I-80 AND POINTS SOUTH
POSSIBLY REACHING THE MID 30S.
WITH DEW POINTS PROGGED TO BE RISING TO ARND FREEZING...THE SNOWMELT
RATES WILL RAMP UP. WITH THE ADDED MOISTURE COUPLED WITH A
MOISTENING MID/UPR LVLS AHEAD OF THE NEXT WEATHER SYSTEM...THE
ENVIRONMENT SEEMS PRIMED FOR THE DEVELOPMENT OF PATCHY/AREAS OF FOG.
FREQUENTLY MELTING SNOW CAN PRODUCE SHALLOW DENSE FOG...SO THIS WILL
CONTINUE TO BE THE FOCUS WED NGT.
CONFIDENCE IN TEMPS...MEDIUM.
CONFIDENCE IN FOG DEVELOPING WED NGT...HIGH.
THURSDAY THROUGH SATURDAY...
MID-LVL FLOW CONTINUES TO PROGRESS INTO A SOUTHWEST SETUP WITH A
500MB VORT MAX PUSHING INTO THE FOUR-CORNERS REGION THUR. SFC
RIDGING IN THE LLVLS WILL BE PARKED OVER THE SOUTHEASTERN
CONUS...ALLOWING FOR CONTINUED FEED OF WARM AIR ADVECTING NORTH
THROUGH THE OZARKS INTO THE OHIO VALLEY/GREAT LAKES REGIONS THUR.
GUIDANCE CONTINUES TO FEATURE A WAVE DEVELOPING ALONG THE LEE-SIDE
OF THE ROCKIES THUR...AS A WEAK SFC RIDGE SAGS SOUTH FROM CENTRAL
CANADA INTO THE UPPER MIDWEST AND SHARPENS UP A BAROCLINIC ZONE OVER
THE NORTHERN PLAINS STRETCHING NORTHEAST THROUGH THE UPPER PENINSULA
OF MICHIGAN. THIS WILL LIKELY KEEP THE WARM AIR OVER THE CWFA
THUR...AND ANY PRECIP WILL LIKELY FALL AS LIQUID THUR. AT THE ONSET
THUR MORNING A BRIEF PERIOD OF FZDZ/FZRA MAY OCCUR...HOWEVER THIS
WILL LIKELY BE BRIEF. GUIDANCE HAS TRENDED SLIGHTLY FURTHER SOUTH
WITH THE SFC LOW FOR THUR NIGHT...AS THE 850MB LOW IS PROGGED TO
SLIDE OVER SOUTH CENTRAL WISC.
WITH SOME DEGREE OF UNCERTAINTY REMAINING IN THE PLACEMENT OF THE
SFC LOW...THIS OPENS UP DECREASED CONFIDENCE IN HIGH TEMPS FOR THUR.
A FURTHER NORTH PATH WOULD PROVIDE TEMPS IN THE MID/UPR
30S...MEANWHILE A CORRECTION TO THE SOUTH WOULD KEEP TEMPS ARND 30
TO LOW 30S. FURTHER COMPOUNDING THIS WOULD BE THE THEN POTENTIAL FOR
P-TYPE ISSUES.
THE SFC RIDGE ACROSS THE UPPER MIDWEST SHUD HELP TO PUSH THE
BAROCLINIC BOUNDARY SOUTH FOR FRI...AS THE LOW LIFTS NORTHEAST OF
THE FORECAST AREA. THIS SHUD AID IN COOLER AIR FILTERING IN BEHIND
AND PUSHING DEW POINTS BACK INTO THE 20S. P-TYPE FOR FRI SHUD BE
LIMITED TO RA/SN...AND TRANSITION TO ALL SN BY FRI AFTN/EVE.
500MB VORT MAX ACROSS THE FAR SOUTHWEST CONUS WILL BEGIN TO DIG
SOUTHEAST OF NEW MEXICO...WHICH WILL LIKELY TRANSLATE IN THE
DOWNSTREAM BOUNDARY SAGGING FURTHER SOUTH THROUGH THE OHIO VALLEY
FRI NGT. THEN YET ANOTHER WAVE IS PROGGED TO DEVELOP ACROSS EASTERN
TEXAS AND TAKE A CLASSIC TRAJECTORY TOWARDS THE OHIO VALLEY FOR THE
SECOND HALF OF THE WEEKEND.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
SUNDAY THROUGH EARLY CHRISTMAS WEEK...
ENSEMBLES INDICATE A SIMILAR COLD SETUP FOR THE SECOND HALF OF THE
WEEKEND INTO EARLY CHRISTMAS WEEK. WESTERN MID-LVL RIDGE MAY BEGIN
TO AMPLIFY FOR EARLY NEXT WEEK...RESULTING IN A DOWNSTREAM TROUGH
POSITIONED OVER THE GREAT LAKES REGION. OPERATIONAL SOLUTIONS
CONTINUE TO POINT TOWARDS A ROBUST WEATHER SYSTEM SUN LIFTING
NORTHEAST ACROSS THE REGION FROM THE SOUTHERN PLAINS/EASTERN
TEXAS...WITH TEMPS COLD ENOUGH TO SUPPORT ALL SNOW FOR THIS EVENT.
THEN ON THE BACKSIDE OF THIS MUCH COLDER AIR POURS BACK INTO THE
CWFA WITH TEMPS ALOFT RETURNING TO -10 TO -14 DEG C AT 850MB FOR
EARLY CHRISTMAS WEEK. THIS WILL KEEP SFC TEMPS IN THE UPPER TEENS TO
LOW 20S.
CONFIDENCE IN SUNDAY SYSTEM...HIGH.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* PERIODIC MVFR CIGS POSSIBLE LATER THIS AFTERNOON INTO THIS
EVENING
* SLIGHT CHANCE OF -SHSN LATE THIS AFTERNOON/EARLY THIS EVENING
IZZI
//DISCUSSION...UPDATED 18Z...
FIRST DISTURBANCE MOVING EAST OF THE AREA WITH CIGS/VSBYS
IMPROVING TO VFR AND SNOW LIKELY END BY 18Z. STEEPENING LOW AND
MID LEVEL LAPSE RATES EXPECTED THIS AFTERNOON WILL ENCOURAGE
INCREASINGLY GUSTY WEST WINDS THIS AFTERNOON. GIVEN THE STEEP
LAPSE RATES AND ANOTHER WEAK DISTURBANCE UPSTREAM CANNOT
COMPLETELY RULE OUT ANOTHER BRIEF SNOW SHOWER LATE THIS AFTERNOON
INTO EARLY THIS EVENING...THOUGH CHANCES LOOK LOW ENOUGH TO KEEP
IT OUT OF THE TAF. COULD ALSO BE SOME PERIODIC MVFR CIGS THIS
AFTERNOON INTO THE EVENING...THOUGH PROBABLY MORE PREVAILING VFR.
WINDS GRADUALLY DIMINISH TONIGHT AND THEN BEGIN TO BACK TO
SOUTHERLY WEDNESDAY MORNING. SOUTH WINDS WILL INCREASE AND ATTAIN
SOME GUSTINESS UP TO 20-25KT WEDNESDAY AFTERNOON.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* LOW CONFIDENCE IN A BRIEF SNOW SHOWER LATE THIS
AFTERNOON/EVENING
* LOW-MEDIUM CONFIDENCE IN CIGS REMAINING VFR
* HIGH CONFIDENCE IN REMAINING FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 18Z...
WEDNESDAY NIGHT...IFR/LIFR CIGS PROBABLY DEVELOPING.
THURSDAY...IFR/LIFR LIKELY. CHANCE OF -RA/DZ.
FRIDAY...IFR LIKELY. CHANCE OF -RA/-SN.
SATURDAY...IFR POSSIBLE. CHANCE OF SNOW...MAINLY AT NIGHT.
SUNDAY...IFR POSSIBLE. CHANCE OF SNOW.
MONDAY...MVFR CIGS POSSIBLE.
IZZI
&&
.MARINE...
315 PM CST
WILL LEAVE HEADLINES AS IS THIS EVENING FOR MARGINAL WESTERLY GALES
ON SOUTHERN PART OF THE LAKE...BUT ALLOW EVENING SHIFT TO ASSESS AND
POSSIBLY CANCEL EARLY. SMALL CRAFT ADVISORY FROM WINTHROP HARBOR TO
GARY IS IN GOOD SHAPE. THEN CONCERN SHIFTS TO LIKELY SOUTH-SOUTHWEST
GALES ON WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT COURTESY OF STRONG
PRESSURE FALLS AND A TIGHT PRESSURE GRADIENT WITH LOW PRESSURE
APPROACHING FROM THE WEST AND HIGH PRESSURE OVER THE OH VALLEY. HAVE
HIGHEST CONFIDENCE IN GALES DEVELOPING ON THE SOUTH HALF WITH
SOMEWHAT LESSER CONFIDENCE ON THE NORTH IN TERMS OF DURATION AND
SEEING PREVAILING GALES...BUT FELT IT WAS PRUDENT TO ISSUE A GALE
WATCH FOR THE ENTIRE OPEN LAKE FROM 21Z WEDS TO 10Z THURS. WILL
LIKELY NEED A SCA FOR THE NEAR SHORE ZONES DURING THIS TIME. AFTER
GALE IS DROPPED FOR GARY TO MI CITY NSH ZONE THIS EVENING...ITS
POSSIBLE THAT THE SCA MAY JUST BE EXTENDED THROUGH TOMORROW NIGHT
FOR THIS ZONE.
A COLD FRONT WILL THEN SHIFT SOUTH DOWN THE LAKE THURSDAY THROUGH
THURSDAY NIGHT..WITH LARGE VARIANCE AMONGST FORECAST GUIDANCE IN
THE TIMING OF THIS FRONT. HAVE FAVORED A SLOWER MOVEMENT OF THE
FRONT DOWN THE SOUTHERN PORTION OF THE LAKE WITH THIS FORECAST
ISSUANCE. THERE IS SOME POTENTIAL FOR FAIRLY STRONG BUT LIKELY
SUB-GALE NORTHERLY WINDS BEHIND THE FRONT. WEAK HIGH PRESSURE WILL
THEN RESULT IN LIGHTER WINDS FRIDAY NIGHT INTO SATURDAY.
HOWEVER...ANOTHER STRONGER SYSTEM THEN LOOKS TO MOVE FROM THE OHIO
VALLEY TOWARD THE CENTRAL LAKES LATE SATURDAY INTO SUNDAY. THE
POTENTIAL CERTAINLY EXISTS FOR NORTHEAST TO NORTH GALES IN
ASSOCIATION WITH THIS SYSTEM DEPENDING ON ITS ULTIMATE TRACK AND
STRENGTH...BUT FOR NOW HAVE INCREASED WINDS TO 30 KT.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878 UNTIL 9 PM TUESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 4 AM
THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL
MIDNIGHT WEDNESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
152 PM CST TUE DEC 17 2013
.DISCUSSION...
328 AM CST
TODAY...
MAIN CONCERNS WILL BE FOCUSED ON THE MID-LVL WAVE THAT IS QUICKLY
SLIDING EAST ACROSS THE WESTERN GREAT LAKES...POSSIBLY BRINGING A
SLUG OF LGT SNOW TO NORTH/NORTHEAST IL AND NORTHWEST IN THIS MORNING
THRU MIDDAY. THEN THE POTENTIAL FOR SOME BLOWING SNOW AS THE
GRADIENT RAMPS UP MIDDAY AND MIXING JUMPS TO ARND 3KFT AGL.
IR IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS THE REGION...AND
SOME COOLING WITH CLOUD TOPS WITH THE WEAK WAVE SLIDING EAST ACROSS
WESTCENTRAL WISC EARLY THIS MORNING. KARX RADAR INDICATES AN AREA OF
RETURNS ACROSS THIS AREA...HOWEVER THE RECENT COUPLE OF HOURS HAVE
INDICATED SOME DOWNWARD TREND IN THE SOUTHERN PORTION OF THIS
PRECIP. SFC OBS ARE NOT INDICATING ANY SNOW IN FAR SOUTHEAST MN AND
HAS TENDED TO BE FOCUSED FURTHER NORTH. BASED ON CURRENT
TRAJECTORY...THE BEST LGT SNOW MAY END UP HOLDING FURTHER NORTH INTO
WISC. BUFR PROFILES HAVE BACKED OFF ON THE OMEGA PLACEMENT...HOWEVER
A HANDFUL OF POINTS CONTINUE TO INDICATE SOME DEGREE OF LIFT THROUGH
THE FAVORED DGZ ARND 12-15Z. DPROG/DT OF THE BUFR SITES ALSO
INDICATES A DOWNWARD TREND...SUPPORTING THE LOWER CONFIDENCE IN SNOW
TOTALS. THE CAVEAT AND CHALLENGE IS THE NARROW CHANNEL OF MOISTURE
THAT STRETCHES WEST AND RECENT RAP GUIDANCE HAS INDICATED AN
ENHANCEMENT TO THIS FEATURE AS IT PIVOTS EAST ACROSS THE CWFA THIS
MORNING.
SNOWFALL RATIOS SHOULD FALL AROUND 20:1...SO RATHER DRY.
BASED ON COBB OUTPUT FROM THESE PROFILES SNOWFALL SHUD GENERALLY
FALL BETWEEN A FEW TENTHS TO 1". COULD SEE AREAS CLOSEST TO THE
WISCONSIN STATELINE PICKING UP SLIGHTLY MORE OR WITHIN A 1-2" RANGE.
THE WAVE WILL REMAIN PROGRESSIVE AND SHUD COME TO AN END BY 15-17Z
FROM WEST TO EAST...AS WIND GUSTS BEGIN TO DEVELOP. ANY FRESH
SNOWFALL SHUD EASILY BLOW AROUND. THIS MAY BE MORE FOCUSED ACROSS
AREAS NORTH OF I-80...AS THE PATCHY DZ EARLY THIS MORNING WILL
MOISTEN UP THE SNOW FURTHER SOUTH AND LIMIT THE ABILITY FOR THE SNOW
TO BLOW AROUND.
TEMPS WILL BEGIN TO REBOUND TDY...AS THE 500MB TROUGH AXIS BEGINS TO
PUSH EAST OF THE WESTERN GREAT LAKES. TEMPS WILL STEADILY WARM INTO
THE UPR 20S TO ARND 30 ACROSS THE SOUTHERN CWFA.
CONFIDENCE IN SNOWFALL...MEDIUM/LOW.
CONFIDENCE IN TEMPS...HIGH.
TONIGHT THROUGH WEDNESDAY...
500MB HEIGHTS BEGIN TO RISE THIS EVENING WITH DIFFLUENT FLOW LIFTING
NORTH FROM THE SFC RIDGE CENTERED ACROSS THE OZARKS. THIS SHUD AID
IN ERODING SOME OF THE CLOUD COVER...AND COULD SEE P-CLOUDY SKIES
FOR A BRIEF PERIOD OVERNIGHT. THEN ANOTHER WEAK MID-LVL WAVE IS
PROGGED TO BUMP INTO THE DIFFLUENT FLOW AND BRING SOME MID-LVL
MOISTURE AND CLOUDS BACK TO THE AREA DURING THE OVERNIGHT HOURS.
500MB FLOW CONTINUES TO EVOLVE INTO A ZONAL SETUP...ALTHOUGH THIS
WILL ONLY BE TEMPORARY THRU WED. SFC RIDGE ACROSS THE OZARKS DRIFTS
EAST TOWARDS THE MID-ATLANTIC/GULF STATES...WITH LLVL FLOW TURNING
SOUTH/SOUTHWEST FOR THE CWFA.
FOR THE FIRST TIME IN SEVERAL DAYS WED MAY SEE THE 850MB 0 DEG
ISOTHERM LIFT OVERHEAD ALONG THE LEADING EDGE OF INCREASED WARM AIR
ADVECTION. THE MID-LVL THERMAL RIDGE CONTINUES TO WARM FURTHER SOUTH
WITH TEMPS RISING TO NEAR 9 DEG C OVER NORTHERN MISSOURI WED AFTN.
GIVEN THE EXPANSIVE SNOW COVER...THE CHALLENGE IS HOW WARM WILL WED
END UP BECOMING. GUIDANCE HAS TRENDED SLIGHTLY COOLER OVER THE PAST
FEW DAYS WITH WED HIGHS. AT THIS TIME THE GENERAL CONSENSUS HAS BEEN
ON TEMPS IN THE LOW 30S ALONG/NORTH OF I-80 AND POINTS SOUTH
POSSIBLY REACHING THE MID 30S.
WITH DEW POINTS PROGGED TO BE RISING TO ARND FREEZING...THE SNOWMELT
RATES WILL RAMP UP. WITH THE ADDED MOISTURE COUPLED WITH A
MOISTENING MID/UPR LVLS AHEAD OF THE NEXT WEATHER SYSTEM...THE
ENVIRONMENT SEEMS PRIMED FOR THE DEVELOPMENT OF PATCHY/AREAS OF FOG.
FREQUENTLY MELTING SNOW CAN PRODUCE SHALLOW DENSE FOG...SO THIS WILL
CONTINUE TO BE THE FOCUS WED NGT.
CONFIDENCE IN TEMPS...MEDIUM.
CONFIDENCE IN FOG DEVELOPING WED NGT...HIGH.
THURSDAY THROUGH SATURDAY...
MID-LVL FLOW CONTINUES TO PROGRESS INTO A SOUTHWEST SETUP WITH A
500MB VORT MAX PUSHING INTO THE FOUR-CORNERS REGION THUR. SFC
RIDGING IN THE LLVLS WILL BE PARKED OVER THE SOUTHEASTERN
CONUS...ALLOWING FOR CONTINUED FEED OF WARM AIR ADVECTING NORTH
THROUGH THE OZARKS INTO THE OHIO VALLEY/GREAT LAKES REGIONS THUR.
GUIDANCE CONTINUES TO FEATURE A WAVE DEVELOPING ALONG THE LEE-SIDE
OF THE ROCKIES THUR...AS A WEAK SFC RIDGE SAGS SOUTH FROM CENTRAL
CANADA INTO THE UPPER MIDWEST AND SHARPENS UP A BAROCLINIC ZONE OVER
THE NORTHERN PLAINS STRETCHING NORTHEAST THROUGH THE UPPER PENINSULA
OF MICHIGAN. THIS WILL LIKELY KEEP THE WARM AIR OVER THE CWFA
THUR...AND ANY PRECIP WILL LIKELY FALL AS LIQUID THUR. AT THE ONSET
THUR MORNING A BRIEF PERIOD OF FZDZ/FZRA MAY OCCUR...HOWEVER THIS
WILL LIKELY BE BRIEF. GUIDANCE HAS TRENDED SLIGHTLY FURTHER SOUTH
WITH THE SFC LOW FOR THUR NIGHT...AS THE 850MB LOW IS PROGGED TO
SLIDE OVER SOUTH CENTRAL WISC.
WITH SOME DEGREE OF UNCERTAINTY REMAINING IN THE PLACEMENT OF THE
SFC LOW...THIS OPENS UP DECREASED CONFIDENCE IN HIGH TEMPS FOR THUR.
A FURTHER NORTH PATH WOULD PROVIDE TEMPS IN THE MID/UPR
30S...MEANWHILE A CORRECTION TO THE SOUTH WOULD KEEP TEMPS ARND 30
TO LOW 30S. FURTHER COMPOUNDING THIS WOULD BE THE THEN POTENTIAL FOR
P-TYPE ISSUES.
THE SFC RIDGE ACROSS THE UPPER MIDWEST SHUD HELP TO PUSH THE
BAROCLINIC BOUNDARY SOUTH FOR FRI...AS THE LOW LIFTS NORTHEAST OF
THE FORECAST AREA. THIS SHUD AID IN COOLER AIR FILTERING IN BEHIND
AND PUSHING DEW POINTS BACK INTO THE 20S. P-TYPE FOR FRI SHUD BE
LIMITED TO RA/SN...AND TRANSITION TO ALL SN BY FRI AFTN/EVE.
500MB VORT MAX ACROSS THE FAR SOUTHWEST CONUS WILL BEGIN TO DIG
SOUTHEAST OF NEW MEXICO...WHICH WILL LIKELY TRANSLATE IN THE
DOWNSTREAM BOUNDARY SAGGING FURTHER SOUTH THROUGH THE OHIO VALLEY
FRI NGT. THEN YET ANOTHER WAVE IS PROGGED TO DEVELOP ACROSS EASTERN
TEXAS AND TAKE A CLASSIC TRAJECTORY TOWARDS THE OHIO VALLEY FOR THE
SECOND HALF OF THE WEEKEND.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
SUNDAY THROUGH EARLY CHRISTMAS WEEK...
ENSEMBLES INDICATE A SIMILAR COLD SETUP FOR THE SECOND HALF OF THE
WEEKEND INTO EARLY CHRISTMAS WEEK. WESTERN MID-LVL RIDGE MAY BEGIN
TO AMPLIFY FOR EARLY NEXT WEEK...RESULTING IN A DOWNSTREAM TROUGH
POSITIONED OVER THE GREAT LAKES REGION. OPERATIONAL SOLUTIONS
CONTINUE TO POINT TOWARDS A ROBUST WEATHER SYSTEM SUN LIFTING
NORTHEAST ACROSS THE REGION FROM THE SOUTHERN PLAINS/EASTERN
TEXAS...WITH TEMPS COLD ENOUGH TO SUPPORT ALL SNOW FOR THIS EVENT.
THEN ON THE BACKSIDE OF THIS MUCH COLDER AIR POURS BACK INTO THE
CWFA WITH TEMPS ALOFT RETURNING TO -10 TO -14 DEG C AT 850MB FOR
EARLY CHRISTMAS WEEK. THIS WILL KEEP SFC TEMPS IN THE UPPER TEENS TO
LOW 20S.
CONFIDENCE IN SUNDAY SYSTEM...HIGH.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* PERIODIC MVFR CIGS POSSIBLE LATER THIS AFTERNOON INTO THIS
EVENING
* SLIGHT CHANCE OF -SHSN LATE THIS AFTERNOON/EARLY THIS EVENING
IZZI
//DISCUSSION...UPDATED 18Z...
FIRST DISTURBANCE MOVING EAST OF THE AREA WITH CIGS/VSBYS
IMPROVING TO VFR AND SNOW LIKELY END BY 18Z. STEEPENING LOW AND
MID LEVEL LAPSE RATES EXPECTED THIS AFTERNOON WILL ENCOURAGE
INCREASINGLY GUSTY WEST WINDS THIS AFTERNOON. GIVEN THE STEEP
LAPSE RATES AND ANOTHER WEAK DISTURBANCE UPSTREAM CANNOT
COMPLETELY RULE OUT ANOTHER BRIEF SNOW SHOWER LATE THIS AFTERNOON
INTO EARLY THIS EVENING...THOUGH CHANCES LOOK LOW ENOUGH TO KEEP
IT OUT OF THE TAF. COULD ALSO BE SOME PERIODIC MVFR CIGS THIS
AFTERNOON INTO THE EVENING...THOUGH PROBABLY MORE PREVAILING VFR.
WINDS GRADUALLY DIMINISH TONIGHT AND THEN BEGIN TO BACK TO
SOUTHERLY WEDNESDAY MORNING. SOUTH WINDS WILL INCREASE AND ATTAIN
SOME GUSTINESS UP TO 20-25KT WEDNESDAY AFTERNOON.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* LOW CONFIDENCE IN A BRIEF SNOW SHOWER LATE THIS
AFTERNOON/EVENING
* LOW-MEDIUM CONFIDENCE IN CIGS REMAINING VFR
* HIGH CONFIDENCE IN REMAINING FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 18Z...
WEDNESDAY NIGHT...IFR/LIFR CIGS PROBABLY DEVELOPING.
THURSDAY...IFR/LIFR LIKELY. CHANCE OF -RA/DZ.
FRIDAY...IFR LIKELY. CHANCE OF -RA/-SN.
SATURDAY...IFR POSSIBLE. CHANCE OF SNOW...MAINLY AT NIGHT.
SUNDAY...IFR POSSIBLE. CHANCE OF SNOW.
MONDAY...MVFR CIGS POSSIBLE.
IZZI
&&
.MARINE...
306 AM CST
FIRST OF ALL MADE NO CHANGES TO THE ONGOING HEADLINES AS THEY ALL
SEEM ON TRACK. A SMALL CRAFT ADVISORY WILL BE NEEDED FOR THE INDIANA
NEARSHORE WATERS AFTER THE GALE WARNING DUE TO LINGERING HAZARDOUS
WAVES.
LOW PRESSURE IS OVER ONTARIO AND IT WILL SLIDE TO THE EAST
TODAY...WHILE ITS COLD FRONT PASSES OVER THE LAKE THIS AFTERNOON.
AT THE SAME TIME HIGH PRESSURE BUILDS OVER THE CENTRAL PLAINS. THIS
WILL TIGHTEN THE PRESSURE GRADIENT OVER THE SOUTHERN END OF THE
LAKE...RESULTING IN LOW END GALES FORMING THIS MORNING THROUGH EARLY
THIS EVENING. WEST WINDS DIMINISH TO ARND 20 KT BY WEDNESDAY
MORNING AS HIGH PRESSURE PASSES TO THE SOUTH. WINDS PICK BACK UP ON
THE BACKSIDE OF THE HIGH LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING. A BRIEF PERIOD OF SW GALES TO 35 KT IS POSSIBLE DURING
THAT TIME. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED AS WELL FOR
WEDNESDAY AFTERNOON AND EVENING. WINDS WEAKEN WEDNESDAY NIGHT AS A
TROUGH OF LOW PRESSURE SITS OVER THE LAKE WEDNESDAY NIGHT THROUGH
THURSDAY. THE NEXT WEAK LOW MOVES OVER THE LAKE THURSDAY NIGHT
BEFORE SHIFTING EAST ON FRIDAY. WINDS TURN LIGHT AND VARIABLE
BEHIND THE LOW ON SATURDAY...BUT THEN TURN NORTH AND STRENGTHEN
SATURDAY NIGHT INTO SUNDAY IN RESPONSE TO THE NEXT SYSTEM. GUIDANCE
FEATURES ANOTHER LOW PUSHING UP THE OHIO RIVER VALLEY SATURDAY NIGHT
INTO SUNDAY WITH HIGH PRESSURE BUILDING DOWN THE PLAINS.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878 UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL
MIDNIGHT WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1132 AM CST TUE DEC 17 2013
.DISCUSSION...
328 AM CST
TODAY...
MAIN CONCERNS WILL BE FOCUSED ON THE MID-LVL WAVE THAT IS QUICKLY
SLIDING EAST ACROSS THE WESTERN GREAT LAKES...POSSIBLY BRINGING A
SLUG OF LGT SNOW TO NORTH/NORTHEAST IL AND NORTHWEST IN THIS MORNING
THRU MIDDAY. THEN THE POTENTIAL FOR SOME BLOWING SNOW AS THE
GRADIENT RAMPS UP MIDDAY AND MIXING JUMPS TO ARND 3KFT AGL.
IR IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS THE REGION...AND
SOME COOLING WITH CLOUD TOPS WITH THE WEAK WAVE SLIDING EAST ACROSS
WESTCENTRAL WISC EARLY THIS MORNING. KARX RADAR INDICATES AN AREA OF
RETURNS ACROSS THIS AREA...HOWEVER THE RECENT COUPLE OF HOURS HAVE
INDICATED SOME DOWNWARD TREND IN THE SOUTHERN PORTION OF THIS
PRECIP. SFC OBS ARE NOT INDICATING ANY SNOW IN FAR SOUTHEAST MN AND
HAS TENDED TO BE FOCUSED FURTHER NORTH. BASED ON CURRENT
TRAJECTORY...THE BEST LGT SNOW MAY END UP HOLDING FURTHER NORTH INTO
WISC. BUFR PROFILES HAVE BACKED OFF ON THE OMEGA PLACEMENT...HOWEVER
A HANDFUL OF POINTS CONTINUE TO INDICATE SOME DEGREE OF LIFT THROUGH
THE FAVORED DGZ ARND 12-15Z. DPROG/DT OF THE BUFR SITES ALSO
INDICATES A DOWNWARD TREND...SUPPORTING THE LOWER CONFIDENCE IN SNOW
TOTALS. THE CAVEAT AND CHALLENGE IS THE NARROW CHANNEL OF MOISTURE
THAT STRETCHES WEST AND RECENT RAP GUIDANCE HAS INDICATED AN
ENHANCEMENT TO THIS FEATURE AS IT PIVOTS EAST ACROSS THE CWFA THIS
MORNING.
SNOWFALL RATIOS SHOULD FALL AROUND 20:1...SO RATHER DRY.
BASED ON COBB OUTPUT FROM THESE PROFILES SNOWFALL SHUD GENERALLY
FALL BETWEEN A FEW TENTHS TO 1". COULD SEE AREAS CLOSEST TO THE
WISCONSIN STATELINE PICKING UP SLIGHTLY MORE OR WITHIN A 1-2" RANGE.
THE WAVE WILL REMAIN PROGRESSIVE AND SHUD COME TO AN END BY 15-17Z
FROM WEST TO EAST...AS WIND GUSTS BEGIN TO DEVELOP. ANY FRESH
SNOWFALL SHUD EASILY BLOW AROUND. THIS MAY BE MORE FOCUSED ACROSS
AREAS NORTH OF I-80...AS THE PATCHY DZ EARLY THIS MORNING WILL
MOISTEN UP THE SNOW FURTHER SOUTH AND LIMIT THE ABILITY FOR THE SNOW
TO BLOW AROUND.
TEMPS WILL BEGIN TO REBOUND TDY...AS THE 500MB TROUGH AXIS BEGINS TO
PUSH EAST OF THE WESTERN GREAT LAKES. TEMPS WILL STEADILY WARM INTO
THE UPR 20S TO ARND 30 ACROSS THE SOUTHERN CWFA.
CONFIDENCE IN SNOWFALL...MEDIUM/LOW.
CONFIDENCE IN TEMPS...HIGH.
TONIGHT THROUGH WEDNESDAY...
500MB HEIGHTS BEGIN TO RISE THIS EVENING WITH DIFFLUENT FLOW LIFTING
NORTH FROM THE SFC RIDGE CENTERED ACROSS THE OZARKS. THIS SHUD AID
IN ERODING SOME OF THE CLOUD COVER...AND COULD SEE P-CLOUDY SKIES
FOR A BRIEF PERIOD OVERNIGHT. THEN ANOTHER WEAK MID-LVL WAVE IS
PROGGED TO BUMP INTO THE DIFFLUENT FLOW AND BRING SOME MID-LVL
MOISTURE AND CLOUDS BACK TO THE AREA DURING THE OVERNIGHT HOURS.
500MB FLOW CONTINUES TO EVOLVE INTO A ZONAL SETUP...ALTHOUGH THIS
WILL ONLY BE TEMPORARY THRU WED. SFC RIDGE ACROSS THE OZARKS DRIFTS
EAST TOWARDS THE MID-ATLANTIC/GULF STATES...WITH LLVL FLOW TURNING
SOUTH/SOUTHWEST FOR THE CWFA.
FOR THE FIRST TIME IN SEVERAL DAYS WED MAY SEE THE 850MB 0 DEG
ISOTHERM LIFT OVERHEAD ALONG THE LEADING EDGE OF INCREASED WARM AIR
ADVECTION. THE MID-LVL THERMAL RIDGE CONTINUES TO WARM FURTHER SOUTH
WITH TEMPS RISING TO NEAR 9 DEG C OVER NORTHERN MISSOURI WED AFTN.
GIVEN THE EXPANSIVE SNOW COVER...THE CHALLENGE IS HOW WARM WILL WED
END UP BECOMING. GUIDANCE HAS TRENDED SLIGHTLY COOLER OVER THE PAST
FEW DAYS WITH WED HIGHS. AT THIS TIME THE GENERAL CONSENSUS HAS BEEN
ON TEMPS IN THE LOW 30S ALONG/NORTH OF I-80 AND POINTS SOUTH
POSSIBLY REACHING THE MID 30S.
WITH DEW POINTS PROGGED TO BE RISING TO ARND FREEZING...THE SNOWMELT
RATES WILL RAMP UP. WITH THE ADDED MOISTURE COUPLED WITH A
MOISTENING MID/UPR LVLS AHEAD OF THE NEXT WEATHER SYSTEM...THE
ENVIRONMENT SEEMS PRIMED FOR THE DEVELOPMENT OF PATCHY/AREAS OF FOG.
FREQUENTLY MELTING SNOW CAN PRODUCE SHALLOW DENSE FOG...SO THIS WILL
CONTINUE TO BE THE FOCUS WED NGT.
CONFIDENCE IN TEMPS...MEDIUM.
CONFIDENCE IN FOG DEVELOPING WED NGT...HIGH.
THURSDAY THROUGH SATURDAY...
MID-LVL FLOW CONTINUES TO PROGRESS INTO A SOUTHWEST SETUP WITH A
500MB VORT MAX PUSHING INTO THE FOUR-CORNERS REGION THUR. SFC
RIDGING IN THE LLVLS WILL BE PARKED OVER THE SOUTHEASTERN
CONUS...ALLOWING FOR CONTINUED FEED OF WARM AIR ADVECTING NORTH
THROUGH THE OZARKS INTO THE OHIO VALLEY/GREAT LAKES REGIONS THUR.
GUIDANCE CONTINUES TO FEATURE A WAVE DEVELOPING ALONG THE LEE-SIDE
OF THE ROCKIES THUR...AS A WEAK SFC RIDGE SAGS SOUTH FROM CENTRAL
CANADA INTO THE UPPER MIDWEST AND SHARPENS UP A BAROCLINIC ZONE OVER
THE NORTHERN PLAINS STRETCHING NORTHEAST THROUGH THE UPPER PENINSULA
OF MICHIGAN. THIS WILL LIKELY KEEP THE WARM AIR OVER THE CWFA
THUR...AND ANY PRECIP WILL LIKELY FALL AS LIQUID THUR. AT THE ONSET
THUR MORNING A BRIEF PERIOD OF FZDZ/FZRA MAY OCCUR...HOWEVER THIS
WILL LIKELY BE BRIEF. GUIDANCE HAS TRENDED SLIGHTLY FURTHER SOUTH
WITH THE SFC LOW FOR THUR NIGHT...AS THE 850MB LOW IS PROGGED TO
SLIDE OVER SOUTH CENTRAL WISC.
WITH SOME DEGREE OF UNCERTAINTY REMAINING IN THE PLACEMENT OF THE
SFC LOW...THIS OPENS UP DECREASED CONFIDENCE IN HIGH TEMPS FOR THUR.
A FURTHER NORTH PATH WOULD PROVIDE TEMPS IN THE MID/UPR
30S...MEANWHILE A CORRECTION TO THE SOUTH WOULD KEEP TEMPS ARND 30
TO LOW 30S. FURTHER COMPOUNDING THIS WOULD BE THE THEN POTENTIAL FOR
P-TYPE ISSUES.
THE SFC RIDGE ACROSS THE UPPER MIDWEST SHUD HELP TO PUSH THE
BAROCLINIC BOUNDARY SOUTH FOR FRI...AS THE LOW LIFTS NORTHEAST OF
THE FORECAST AREA. THIS SHUD AID IN COOLER AIR FILTERING IN BEHIND
AND PUSHING DEW POINTS BACK INTO THE 20S. P-TYPE FOR FRI SHUD BE
LIMITED TO RA/SN...AND TRANSITION TO ALL SN BY FRI AFTN/EVE.
500MB VORT MAX ACROSS THE FAR SOUTHWEST CONUS WILL BEGIN TO DIG
SOUTHEAST OF NEW MEXICO...WHICH WILL LIKELY TRANSLATE IN THE
DOWNSTREAM BOUNDARY SAGGING FURTHER SOUTH THROUGH THE OHIO VALLEY
FRI NGT. THEN YET ANOTHER WAVE IS PROGGED TO DEVELOP ACROSS EASTERN
TEXAS AND TAKE A CLASSIC TRAJECTORY TOWARDS THE OHIO VALLEY FOR THE
SECOND HALF OF THE WEEKEND.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
SUNDAY THROUGH EARLY CHRISTMAS WEEK...
ENSEMBLES INDICATE A SIMILAR COLD SETUP FOR THE SECOND HALF OF THE
WEEKEND INTO EARLY CHRISTMAS WEEK. WESTERN MID-LVL RIDGE MAY BEGIN
TO AMPLIFY FOR EARLY NEXT WEEK...RESULTING IN A DOWNSTREAM TROUGH
POSITIONED OVER THE GREAT LAKES REGION. OPERATIONAL SOLUTIONS
CONTINUE TO POINT TOWARDS A ROBUST WEATHER SYSTEM SUN LIFTING
NORTHEAST ACROSS THE REGION FROM THE SOUTHERN PLAINS/EASTERN
TEXAS...WITH TEMPS COLD ENOUGH TO SUPPORT ALL SNOW FOR THIS EVENT.
THEN ON THE BACKSIDE OF THIS MUCH COLDER AIR POURS BACK INTO THE
CWFA WITH TEMPS ALOFT RETURNING TO -10 TO -14 DEG C AT 850MB FOR
EARLY CHRISTMAS WEEK. THIS WILL KEEP SFC TEMPS IN THE UPPER TEENS TO
LOW 20S.
CONFIDENCE IN SUNDAY SYSTEM...HIGH.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* PERIODIC MVFR CIGS POSSIBLE LATE THIS AFTERNOON INTO THIS EVENING
* SLIGHT CHANCE OF -SHSN LATE THIS AFTERNOON/EARLY THIS EVENING
IZZI
//DISCUSSION...UPDATED 18Z...
FIRST DISTURBANCE MOVING EAST OF THE AREA WITH CIGS/VSBYS
IMPROVING TO VFR AND SNOW LIKELY END BY 18Z. STEEPENING LOW AND
MID LEVEL LAPSE RATES EXPECTED THIS AFTERNOON WILL ENCOURAGE
INCREASINGLY GUSTY WEST WINDS THIS AFTERNOON. GIVEN THE STEEP
LAPSE RATES AND ANOTHER WEAK DISTURBANCE UPSTREAM CANNOT
COMPLETELY RULE OUT ANOTHER BRIEF SNOW SHOWER LATE THIS AFTERNOON
INTO EARLY THIS EVENING...THOUGH CHANCES LOOK LOW ENOUGH TO KEEP
IT OUT OF THE TAF. COULD ALSO BE SOME PERIODIC MVFR CIGS THIS
AFTERNOON INTO THE EVENING...THOUGH PROBABLY MORE PREVAILING VFR.
WINDS GRADUALLY DIMINISH TONIGHT AND THEN BEGIN TO BACK TO
SOUTHERLY WEDNESDAY MORNING. SOUTH WINDS WILL INCREASE AND ATTAIN
SOME GUSTINESS UP TO 20-25KT WEDNESDAY AFTERNOON.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* LOW CONFIDENCE IN A BRIEF SNOW SHOWER LATE THIS
AFTERNOON/EVENING
* LOW-MEDIUM CONFIDENCE IN CIGS REMAINING VFR
* HIGH CONFIDENCE IN REMAINING FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 18Z...
WEDNESDAY NIGHT...IFR/LIFR CIGS PROBABLY DEVELOPING.
THURSDAY...IFR/LIFR LIKELY. CHANCE OF -RA/DZ.
FRIDAY...IFR LIKELY. CHANCE OF -RA/-SN.
SATURDAY...IFR POSSIBLE. CHANCE OF SNOW...MAINLY AT NIGHT.
SUNDAY...IFR POSSIBLE. CHANCE OF SNOW.
MONDAY...MVFR CIGS POSSIBLE.
IZZI
&&
.MARINE...
306 AM CST
FIRST OF ALL MADE NO CHANGES TO THE ONGOING HEADLINES AS THEY ALL
SEEM ON TRACK. A SMALL CRAFT ADVISORY WILL BE NEEDED FOR THE INDIANA
NEARSHORE WATERS AFTER THE GALE WARNING DUE TO LINGERING HAZARDOUS
WAVES.
LOW PRESSURE IS OVER ONTARIO AND IT WILL SLIDE TO THE EAST
TODAY...WHILE ITS COLD FRONT PASSES OVER THE LAKE THIS AFTERNOON.
AT THE SAME TIME HIGH PRESSURE BUILDS OVER THE CENTRAL PLAINS. THIS
WILL TIGHTEN THE PRESSURE GRADIENT OVER THE SOUTHERN END OF THE
LAKE...RESULTING IN LOW END GALES FORMING THIS MORNING THROUGH EARLY
THIS EVENING. WEST WINDS DIMINISH TO ARND 20 KT BY WEDNESDAY
MORNING AS HIGH PRESSURE PASSES TO THE SOUTH. WINDS PICK BACK UP ON
THE BACKSIDE OF THE HIGH LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING. A BRIEF PERIOD OF SW GALES TO 35 KT IS POSSIBLE DURING
THAT TIME. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED AS WELL FOR
WEDNESDAY AFTERNOON AND EVENING. WINDS WEAKEN WEDNESDAY NIGHT AS A
TROUGH OF LOW PRESSURE SITS OVER THE LAKE WEDNESDAY NIGHT THROUGH
THURSDAY. THE NEXT WEAK LOW MOVES OVER THE LAKE THURSDAY NIGHT
BEFORE SHIFTING EAST ON FRIDAY. WINDS TURN LIGHT AND VARIABLE
BEHIND THE LOW ON SATURDAY...BUT THEN TURN NORTH AND STRENGTHEN
SATURDAY NIGHT INTO SUNDAY IN RESPONSE TO THE NEXT SYSTEM. GUIDANCE
FEATURES ANOTHER LOW PUSHING UP THE OHIO RIVER VALLEY SATURDAY NIGHT
INTO SUNDAY WITH HIGH PRESSURE BUILDING DOWN THE PLAINS.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878 UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL
MIDNIGHT WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1022 AM CST TUE DEC 17 2013
.DISCUSSION...
328 AM CST
TODAY...
MAIN CONCERNS WILL BE FOCUSED ON THE MID-LVL WAVE THAT IS QUICKLY
SLIDING EAST ACROSS THE WESTERN GREAT LAKES...POSSIBLY BRINGING A
SLUG OF LGT SNOW TO NORTH/NORTHEAST IL AND NORTHWEST IN THIS MORNING
THRU MIDDAY. THEN THE POTENTIAL FOR SOME BLOWING SNOW AS THE
GRADIENT RAMPS UP MIDDAY AND MIXING JUMPS TO ARND 3KFT AGL.
IR IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS THE REGION...AND
SOME COOLING WITH CLOUD TOPS WITH THE WEAK WAVE SLIDING EAST ACROSS
WESTCENTRAL WISC EARLY THIS MORNING. KARX RADAR INDICATES AN AREA OF
RETURNS ACROSS THIS AREA...HOWEVER THE RECENT COUPLE OF HOURS HAVE
INDICATED SOME DOWNWARD TREND IN THE SOUTHERN PORTION OF THIS
PRECIP. SFC OBS ARE NOT INDICATING ANY SNOW IN FAR SOUTHEAST MN AND
HAS TENDED TO BE FOCUSED FURTHER NORTH. BASED ON CURRENT
TRAJECTORY...THE BEST LGT SNOW MAY END UP HOLDING FURTHER NORTH INTO
WISC. BUFR PROFILES HAVE BACKED OFF ON THE OMEGA PLACEMENT...HOWEVER
A HANDFUL OF POINTS CONTINUE TO INDICATE SOME DEGREE OF LIFT THROUGH
THE FAVORED DGZ ARND 12-15Z. DPROG/DT OF THE BUFR SITES ALSO
INDICATES A DOWNWARD TREND...SUPPORTING THE LOWER CONFIDENCE IN SNOW
TOTALS. THE CAVEAT AND CHALLENGE IS THE NARROW CHANNEL OF MOISTURE
THAT STRETCHES WEST AND RECENT RAP GUIDANCE HAS INDICATED AN
ENHANCEMENT TO THIS FEATURE AS IT PIVOTS EAST ACROSS THE CWFA THIS
MORNING.
SNOWFALL RATIOS SHOULD FALL AROUND 20:1...SO RATHER DRY.
BASED ON COBB OUTPUT FROM THESE PROFILES SNOWFALL SHUD GENERALLY
FALL BETWEEN A FEW TENTHS TO 1". COULD SEE AREAS CLOSEST TO THE
WISCONSIN STATELINE PICKING UP SLIGHTLY MORE OR WITHIN A 1-2" RANGE.
THE WAVE WILL REMAIN PROGRESSIVE AND SHUD COME TO AN END BY 15-17Z
FROM WEST TO EAST...AS WIND GUSTS BEGIN TO DEVELOP. ANY FRESH
SNOWFALL SHUD EASILY BLOW AROUND. THIS MAY BE MORE FOCUSED ACROSS
AREAS NORTH OF I-80...AS THE PATCHY DZ EARLY THIS MORNING WILL
MOISTEN UP THE SNOW FURTHER SOUTH AND LIMIT THE ABILITY FOR THE SNOW
TO BLOW AROUND.
TEMPS WILL BEGIN TO REBOUND TDY...AS THE 500MB TROUGH AXIS BEGINS TO
PUSH EAST OF THE WESTERN GREAT LAKES. TEMPS WILL STEADILY WARM INTO
THE UPR 20S TO ARND 30 ACROSS THE SOUTHERN CWFA.
CONFIDENCE IN SNOWFALL...MEDIUM/LOW.
CONFIDENCE IN TEMPS...HIGH.
TONIGHT THROUGH WEDNESDAY...
500MB HEIGHTS BEGIN TO RISE THIS EVENING WITH DIFFLUENT FLOW LIFTING
NORTH FROM THE SFC RIDGE CENTERED ACROSS THE OZARKS. THIS SHUD AID
IN ERODING SOME OF THE CLOUD COVER...AND COULD SEE P-CLOUDY SKIES
FOR A BRIEF PERIOD OVERNIGHT. THEN ANOTHER WEAK MID-LVL WAVE IS
PROGGED TO BUMP INTO THE DIFFLUENT FLOW AND BRING SOME MID-LVL
MOISTURE AND CLOUDS BACK TO THE AREA DURING THE OVERNIGHT HOURS.
500MB FLOW CONTINUES TO EVOLVE INTO A ZONAL SETUP...ALTHOUGH THIS
WILL ONLY BE TEMPORARY THRU WED. SFC RIDGE ACROSS THE OZARKS DRIFTS
EAST TOWARDS THE MID-ATLANTIC/GULF STATES...WITH LLVL FLOW TURNING
SOUTH/SOUTHWEST FOR THE CWFA.
FOR THE FIRST TIME IN SEVERAL DAYS WED MAY SEE THE 850MB 0 DEG
ISOTHERM LIFT OVERHEAD ALONG THE LEADING EDGE OF INCREASED WARM AIR
ADVECTION. THE MID-LVL THERMAL RIDGE CONTINUES TO WARM FURTHER SOUTH
WITH TEMPS RISING TO NEAR 9 DEG C OVER NORTHERN MISSOURI WED AFTN.
GIVEN THE EXPANSIVE SNOW COVER...THE CHALLENGE IS HOW WARM WILL WED
END UP BECOMING. GUIDANCE HAS TRENDED SLIGHTLY COOLER OVER THE PAST
FEW DAYS WITH WED HIGHS. AT THIS TIME THE GENERAL CONSENSUS HAS BEEN
ON TEMPS IN THE LOW 30S ALONG/NORTH OF I-80 AND POINTS SOUTH
POSSIBLY REACHING THE MID 30S.
WITH DEW POINTS PROGGED TO BE RISING TO ARND FREEZING...THE SNOWMELT
RATES WILL RAMP UP. WITH THE ADDED MOISTURE COUPLED WITH A
MOISTENING MID/UPR LVLS AHEAD OF THE NEXT WEATHER SYSTEM...THE
ENVIRONMENT SEEMS PRIMED FOR THE DEVELOPMENT OF PATCHY/AREAS OF FOG.
FREQUENTLY MELTING SNOW CAN PRODUCE SHALLOW DENSE FOG...SO THIS WILL
CONTINUE TO BE THE FOCUS WED NGT.
CONFIDENCE IN TEMPS...MEDIUM.
CONFIDENCE IN FOG DEVELOPING WED NGT...HIGH.
THURSDAY THROUGH SATURDAY...
MID-LVL FLOW CONTINUES TO PROGRESS INTO A SOUTHWEST SETUP WITH A
500MB VORT MAX PUSHING INTO THE FOUR-CORNERS REGION THUR. SFC
RIDGING IN THE LLVLS WILL BE PARKED OVER THE SOUTHEASTERN
CONUS...ALLOWING FOR CONTINUED FEED OF WARM AIR ADVECTING NORTH
THROUGH THE OZARKS INTO THE OHIO VALLEY/GREAT LAKES REGIONS THUR.
GUIDANCE CONTINUES TO FEATURE A WAVE DEVELOPING ALONG THE LEE-SIDE
OF THE ROCKIES THUR...AS A WEAK SFC RIDGE SAGS SOUTH FROM CENTRAL
CANADA INTO THE UPPER MIDWEST AND SHARPENS UP A BAROCLINIC ZONE OVER
THE NORTHERN PLAINS STRETCHING NORTHEAST THROUGH THE UPPER PENINSULA
OF MICHIGNA. THIS WILL LIKELY KEEP THE WARM AIR OVER THE CWFA
THUR...AND ANY PRECIP WILL LIKELY FALL AS LIQUID THUR. AT THE ONSET
THUR MORNING A BRIEF PERIOD OF FZDZ/FZRA MAY OCCUR...HOWEVER THIS
WILL LIKELY BE BRIEF. GUIDANCE HAS TRENDED SLIGHTLY FURTHER SOUTH
WITH THE SFC LOW FOR THUR NIGHT...AS THE 850MB LOW IS PROGGED TO
SLIDE OVER SOUTHCENTRAL WISC.
WITH SOME DEGREE OF UNCERTAINTY REMAINING IN THE PLACEMENT OF THE
SFC LOW...THIS OPENS UP DECREASED CONFIDENCE IN HIGH TEMPS FOR THUR.
A FURTHER NORTH PATH WOULD PROVIDE TEMPS IN THE MID/UPR
30S...MEANWHILE A CORRECTION TO THE SOUTH WOULD KEEP TEMPS ARND 30
TO LOW 30S. FURTHER COMPOUNDING THIS WOULD BE THE THEN POTENTIAL FOR
P-TYPE ISSUES.
THE SFC RIDGE ACROSS THE UPPER MIDWEST SHUD HELP TO PUSH THE
BAROCLINIC BOUNDARY SOUTH FOR FRI...AS THE LOW LIFTS NORTHEAST OF
THE FORECAST AREA. THIS SHUD AID IN COOLER AIR FILTERING IN BEHIND
AND PUSHING DEW POINTS BACK INTO THE 20S. P-TYPE FOR FRI SHUD BE
LIMITED TO RA/SN...AND TRANSITION TO ALL SN BY FRI AFTN/EVE.
500MB VORT MAX ACROSS THE FAR SOUTHWEST CONUS WILL BEGIN TO DIG
SOUTHEAST OF NEW MEXICO...WHICH WILL LIKELY TRANSLATE IN THE
DOWNSTREAM BOUNDARY SAGGING FURTHER SOUTH THROUGH THE OHIO VALLEY
FRI NGT. THEN YET ANOTHER WAVE IS PROGGED TO DEVELOP ACROSS EASTERN
TEXAS AND TAKE A CLASSIC TRAJECTORY TOWARDS THE OHIO VALLEY FOR THE
SECOND HALF OF THE WEEKEND.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
SUNDAY THROUGH EARLY CHRISTMAS WEEK...
ENSEMBLES INDICATE A SIMILAR COLD SETUP FOR THE SECOND HALF OF THE
WEEKEND INTO EARLY CHRISTMAS WEEK. WESTERN MID-LVL RIDGE MAY BEGIN
TO AMPLIFY FOR EARLY NEXT WEEK...RESULTING IN A DOWNSTREAM TROUGH
POSITIONED OVER THE GREAT LAKES REGION. OPERATIONAL SOLUTIONS
CONTINUE TO POINT TOWARDS A ROBUST WEATHER SYSTEM SUN LIFTING
NORTHEAST ACROSS THE REGION FROM THE SOUTHERN PLAINS/EASTERN
TEXAS...WITH TEMPS COLD ENOUGH TO SUPPORT ALL SNOW FOR THIS EVENT.
THEN ON THE BACKSIDE OF THIS MUCH COLDER AIR POURS BACK INTO THE
CWFA WITH TEMPS ALOFT RETURNING TO -10 TO -14 DEG C AT 850MB FOR
EARLY CHRISTMAS WEEK. THIS WILL KEEP SFC TEMPS IN THE UPPER TEENS TO
LOW 20S.
CONFIDENCE IN SUNDAY SYSTEM...HIGH.
CONFIDENCE IN TEMPS...MEDIUM/HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* TRENDING VFR THIS AFTERNOON
* GUSTY WEST WINDS THIS AFTERNOON
IZZI
//DISCUSSION...UPDATED 14Z
RADAR TRENDS SHOW SNOW SHOWERS DRYING UP OVER THE AREA AND HAVE
CONSIDERABLY BACKED OFF ON SNOW MENTION IN THE TAFS. VSBY ALREADY
JUST BARELY ABOVE IFR...SO WOULDNT TAKE MUCH SNOW TO DROP VSBY TO
IFR BUT ACCUMS SHOULD JUST BE A DUSTING AT WORST. NORTH-SOUTH EDGE
TO IFR CIGS MAKING STEADY PROGRESS EAST AND SHOULD CLEAR OUT OF
ORD/MDW BY 17Z.
IZZI
UPDATED 12Z...
IFR CIGS HAVE SPREAD ACROSS THE TERMINALS AS THE LOW PRESSURE
TROUGH APPROACHES FROM THE WEST. THE MAIN LOW WILL PASS TO OUR
NORTH THROUGH ONTARIO TODAY...WITH ITS COLD FRONT SWINGING THROUGH
THIS AFTN. A BAND OF SNOW HAS FORMED OVER SOUTHERN WI AND
EXPECTING IT TO REACH RFD ARND 1230Z...THEN AT ORD BY 13Z. UNTIL
THEN...EXPECTING CONDITIONS TO STAY RIGHT WHERE THEY ARE. IFR
CIGS AND VFR/MVFR VSBY. WHEN THE SNOW ARRIVES...VSBYS WILL FALL
FURTHER TO AROUND A MILE. THERE SHOULD BE A BRIEF PERIOD OF
HEAVIER SNOW WITH VSBYS BELOW 1 MILE.
WINDS PICK UP AFTER THE COLD FRONT WITH GUSTS AROUND 30 KT. KEPT
MVFR CIGS GOING...BUT GUIDANCE SUGGESTS MVFR OR LOWER CIGS COULD
HANG AROUND LONGER THAN CURRENTLY FORECAST. BLOWING SNOW WILL
LIKELY BE AN ISSUE GIVEN THE FRESH LIGHT SNOW. NOT EXPECTING IT TO
IMPACT VSBY THOUGH.
HIGH PRESSURE PASSES TO THE SOUTH OVERNIGHT WITH WINDS BECOMING
SOUTHWEST AROUND 10 KT. WINDS TURN FURTHER SOUTH AND BEGIN GUSTING
TO AROUND 20 KT IN THE LATE MORNING...BUT EXPECTING VFR CONDITIONS.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM CONFIDENCE ON VFR CIGS THIS AFTERNOON
* HIGH CONFIDENCE IN REST OF FORECAST
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...IFR/LIFR CIGS PROBABLY DEVELOPING.
THURSDAY...IFR/LIFR LIKELY. CHANCE OF -RA/DZ.
FRIDAY...IFR LIKELY. CHANCE OF -RA/-SN.
SATURDAY...IFR POSSIBLE. CHANCE OF SNOW...MAINLY AT NIGHT.
SUNDAY...IFR POSSIBLE. CHANCE OF SNOW.
MONDAY...MVFR CIGS POSSIBLE.
IZZI
&&
.MARINE...
306 AM CST
FIRST OF ALL MADE NO CHANGES TO THE ONGOING HEADLINES AS THEY ALL
SEEM ON TRACK. A SMALL CRAFT ADVISORY WILL BE NEEDED FOR THE INDIANA
NEARSHORE WATERS AFTER THE GALE WARNING DUE TO LINGERING HAZARDOUS
WAVES.
LOW PRESSURE IS OVER ONTARIO AND IT WILL SLIDE TO THE EAST
TODAY...WHILE ITS COLD FRONT PASSES OVER THE LAKE THIS AFTERNOON.
AT THE SAME TIME HIGH PRESSURE BUILDS OVER THE CENTRAL PLAINS. THIS
WILL TIGHTEN THE PRESSURE GRADIENT OVER THE SOUTHERN END OF THE
LAKE...RESULTING IN LOW END GALES FORMING THIS MORNING THROUGH EARLY
THIS EVENING. WEST WINDS DIMINISH TO ARND 20 KT BY WEDNESDAY
MORNING AS HIGH PRESSURE PASSES TO THE SOUTH. WINDS PICK BACK UP ON
THE BACKSIDE OF THE HIGH LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING. A BRIEF PERIOD OF SW GALES TO 35 KT IS POSSIBLE DURING
THAT TIME. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED AS WELL FOR
WEDNESDAY AFTERNOON AND EVENING. WINDS WEAKEN WEDNESDAY NIGHT AS A
TROUGH OF LOW PRESSURE SITS OVER THE LAKE WEDNESDAY NIGHT THROUGH
THURSDAY. THE NEXT WEAK LOW MOVES OVER THE LAKE THURSDAY NIGHT
BEFORE SHIFTING EAST ON FRIDAY. WINDS TURN LIGHT AND VARIABLE
BEHIND THE LOW ON SATURDAY...BUT THEN TURN NORTH AND STRENGTHEN
SATURDAY NIGHT INTO SUNDAY IN RESPONSE TO THE NEXT SYSTEM. GUIDANCE
FEATURES ANOTHER LOW PUSHING UP THE OHIO RIVER VALLEY SATURDAY NIGHT
INTO SUNDAY WITH HIGH PRESSURE BUILDING DOWN THE PLAINS.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878 UNTIL 9 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL
MIDNIGHT WEDNESDAY.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS JACKSON KY
342 PM EST TUE DEC 17 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 331 PM EST TUE DEC 17 2013
MODELS HAVE BEEN CHANGING THROUGHOUT THE LAST 24 HOURS...MAKING IT
HARD TO PINPOINT AN EXACT FORECAST UNTIL LOOKING AT ONGOING
CONDITIONS. SO FAR TODAY...THE HRRR SEEMS TO BE INITIALIZING THE
BEST WITH ONGOING CONDITIONS...AND THE OTHER HIRES MODELS HAVE
FOLLOWED SUIT THROUGHOUT THE DAY. BASED ON CURRENT TRENDS...AND
LATEST HIRES MODEL DATA...FAVOR A LESS IMPACTFUL EVENING WITH MAINLY
LIGHT RAIN...ENDING BEFORE MIDNIGHT IN MOST AREAS.
WITH TEMPERATURES WELL ABOVE FREEZING IN MOST LOCATIONS RIGHT
NOW...AND ROAD TEMPS SITTING ABOVE FREEZING AS WELL...DO NOT EXPECT
ANY IMPACTS OTHER THAN SOME LIGHT RAIN...MAINLY NORTH OF THE
MOUNTAIN PARKWAY. CLOUD COVER CURRENTLY EXTENDS SOUTHWARD ACROSS
MUCH OF THE CWA. AS PRECIPITATION QUICKLY MOVES OFF TO THE
EAST...TEMPERATURES WILL COOL WITH LOSS OF DAYTIME HEATING...BUT
LATEST DATA SUPPORTS THE IDEA THAT TEMPS WILL STILL BE ABOVE
FREEZING THROUGH MOST OF THE EVENING. ANY SNOW THAT DOES FALL WILL
BE LATE IN THE EVENING ACROSS THE FAR EASTERN CWA /PIKE COUNTY/...AS
WELL AS ACROSS SOME OF THE HIGHEST TERRAIN NEAR THE VIRGINIA BORDER.
DROPPED SNOW TOTALS SUBSTANTIALLY...WITH ONLY A COUPLE TENTHS
EXPECTED IN THE HIGHEST TERRAIN. NEIGHBORING OFFICES SEEM TO HAVE
FOLLOWED SUIT WITH THIS LOWER IMPACT SOLUTION AS WELL.
THE PRECIPITATION SHOULD CLEAR EARLY IN THE NIGHT...WITH DRY AND
COLDER AIR FILTERING IN BEHIND...EFFECTIVELY CUTTING OFF THE CLOUD
COVER FROM WEST TO EAST. AS THIS COLDER AIRMASS TAKES HOLD...AND
CLOUDS CLEAR...EXPECT TEMPS TO MIX OUT OVERNIGHT INTO THE MID 20S
ACROSS MUCH OF THE REGION. SUNNY SKIES WILL FINALLY MAKE AN
APPEARANCE DURING THE DAY TOMORROW AS HIGH PRESSURE REMAINS IN
CONTROL. TEMPERATURES WILL BE ON THE COOLER SIDE COMPARED TO
TODAY...BUT WILL STILL BE ABLE TO WARM UP TO ABOUT THE 40 DEGREE
MARK. NAM12 FORECAST SOUNDINGS SHOW THE ATMOSPHERE BECOMING QUITE
DRY...WITH DEW POINTS DROPPING SUBSTANTIALLY. THIS WILL ESPECIALLY
BE THE CASE IN THE HIGHER TERRAIN WEDNESDAY NIGHT...WHERE DEW POINTS
COULD DROP AS LOW AS 9 DEGREES. OVERNIGHT LOW TEMPS WILL DROP TO
AROUND FREEZING OR SLIGHTLY BELOW...WITH A GOOD SET UP FOR A RIDGE
VALLEY SPLIT TO OCCUR.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 341 PM EST TUE DEC 17 2013
THE EXTENDED FORECAST PERIOD BEGINS ON THURSDAY WITH A MAINLY
ZONAL PATTERN OVER THE CONUS WITH AN UPPER LEVEL LOW OVER THE
SOUTHWEST. THE BIG QUESTION BECOMES THE TIMING OF THE UPPER LOW AS
IT MOVES TO THE EAST AND WHERE THE FRONT SETS UP OVER THE OHIO
VALLEY. THE CURRENT TREND IN THE MODELS IS FOR A STRONGER LOW TO
FORM ON THE FRONT TO THE WEST OF THE AREA. THIS SOLUTION WILL
CREATE A SHARP WAVE ON THE FRONT AND PUSH A WARM FRONT TO THE NORTH
OF THE AREA. THIS SOLUTION WOULD PRODUCE MUCH LESS RAINFALL BECAUSE
THE STATIONARY FRONT WOULD STAY TO THE WEST AND NORTH OF EASTERN
KENTUCKY. THE JURY IS REALLY STILL OUT ON THIS SOLUTION AND WOULD
NOT BE TOO SURPRISED TO SEE A COUPLE DIFFERENT SOLUTIONS BEFORE THE
WEEKEND GETS HERE. AS SUCH...TIMING OF THE SYSTEM AND THE AMOUNT OF
RAINFALL IS FAIRLY LOW CONFIDENCE. IN ADDITION...HAVE SEEN THE
MODELS STRUGGLE TIME AND TIME AGAIN WITH TRYING TO NAIL DOWN
TRANSITIONS IN THE PATTERN LIKE THE ONE WE ARE SEEING. DID TREND THE
FORECAST TO THE NEWER MODEL BLEND. ALSO WITH THIS SOLUTION...THERE
WILL NOT BE MUCH TIME TO GET ANY COLD AIR INTO THE AREA AS THE FRONT
MOVES THROUGH. THIS WILL DECREASE THE CHANCES FOR WINTRY
PRECIPITATION ON THE BACK END OF THE FRONT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1259 PM EST TUE DEC 17 2013
LOW CIGS CONTINUE ACROSS THE NORTHER CWA AS A SHORTWAVE CONTINUES TO
MOVE ACROSS THE REGION. THIS HAS PRODUCED A LINE OF WEAK SHOWERS
MAINLY NORTH OF THE MOUNTAIN PARKWAY...POSING LITTLE THREAT TO VIS.
THE ONLY TAF SITE WHICH MAY POSSIBLY BE IMPACTED BY THIS RAIN IS
KSJS...BUT IMPACTS WILL BE MINIMAL. AS WE CONTINUE THROUGHOUT THE
EVENING...EXPECT THE SHORTWAVE TO SHIFT SE...BRINGING INCREASING POPS
TO THE FAR SE COUNTIES...MAINLY ALONG THE VA AND WV BORDER. AS
TEMPERATURES FALL THROUGHOUT THE EVENING...THIS PRECIPITATION WILL
CHANGE OVER TO SNOW. BUT ONCE AGAIN...THE ONLY TAF SITE WHICH SHOULD
FEEL ANY IMPACTS FROM THIS WILL BE KSJS. DROPPED THE CIGS AT KSJS TO
MVFR AS THE PRECIPITATION MOVES THROUGH...BEFORE CLEARING OUT LATE
TONIGHT AS HIGH PRESSURE MOVES IN OVERHEAD. FOR THE REMAINING TAF
SITES...SOME LOW CLOUDS MAY BE FELT LATER IN THE EVENING AS THE
SHORTWAVE MOVES SE ACROSS THE AREA. HOWEVER...BASED ON LATEST NAM12
AND GFSLAMP DATA...THESE CLOUDS SHOULD STAY RIGHT AT OR SLIGHTLY
ABOVE THE VFR RANGE...BEFORE CLEARING OUT LATE TONIGHT.
AS FAR AS WINDS...HIGH PRESSURE GRADIENTS ACROSS THE REGION TODAY AND
THIS EVENING SHOULD LEAD TO SOME POSSIBLE GUSTS IN THE 15 TO 20KT
RANGE. UNFORTUNATELY...RECENT OBSERVATIONS HAVE NOT SHOWN THIS
MATERIALIZING AS WELL...THOUGH THE POTENTIAL IS MOST CERTAINLY
STILL THERE. WENT AHEAD AND KEPT WINDS AT 10KTS OR SO...BUT DID TAKE
OUT GUSTS THROUGH THIS EVENING. AS MENTIONED ABOVE...WILL CONTINUE TO
MONITOR THIS AS WELL IN CASE CHANGES NEED TO BE MADE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JMW
LONG TERM...JJ
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
332 PM EST TUE DEC 17 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 331 PM EST TUE DEC 17 2013
MODELS HAVE BEEN CHANGING THROUGHOUT THE LAST 24 HOURS...MAKING IT
HARD TO PINPOINT AN EXACT FORECAST UNTIL LOOKING AT ONGOING
CONDITIONS. SO FAR TODAY...THE HRRR SEEMS TO BE INITIALIZING THE
BEST WITH ONGOING CONDITIONS...AND THE OTHER HIRES MODELS HAVE
FOLLOWED SUIT THROUGHOUT THE DAY. BASED ON CURRENT TRENDS...AND
LATEST HIRES MODEL DATA...FAVOR A LESS IMPACTFUL EVENING WITH MAINLY
LIGHT RAIN...ENDING BEFORE MIDNIGHT IN MOST AREAS.
WITH TEMPERATURES WELL ABOVE FREEZING IN MOST LOCATIONS RIGHT
NOW...AND ROAD TEMPS SITTING ABOVE FREEZING AS WELL...DO NOT EXPECT
ANY IMPACTS OTHER THAN SOME LIGHT RAIN...MAINLY NORTH OF THE
MOUNTAIN PARKWAY. CLOUD COVER CURRENTLY EXTENDS SOUTHWARD ACROSS
MUCH OF THE CWA. AS PRECIPITATION QUICKLY MOVES OFF TO THE
EAST...TEMPERATURES WILL COOL WITH LOSS OF DAYTIME HEATING...BUT
LATEST DATA SUPPORTS THE IDEA THAT TEMPS WILL STILL BE ABOVE
FREEZING THROUGH MOST OF THE EVENING. ANY SNOW THAT DOES FALL WILL
BE LATE IN THE EVENING ACROSS THE FAR EASTERN CWA /PIKE COUNTY/...AS
WELL AS ACROSS SOME OF THE HIGHEST TERRAIN NEAR THE VIRGINIA BORDER.
DROPPED SNOW TOTALS SUBSTANTIALLY...WITH ONLY A COUPLE TENTHS
EXPECTED IN THE HIGHEST TERRAIN. NEIGHBORING OFFICES SEEM TO HAVE
FOLLOWED SUIT WITH THIS LOWER IMPACT SOLUTION AS WELL.
THE PRECIPITATION SHOULD CLEAR EARLY IN THE NIGHT...WITH DRY AND
COLDER AIR FILTERING IN BEHIND...EFFECTIVELY CUTTING OFF THE CLOUD
COVER FROM WEST TO EAST. AS THIS COLDER AIRMASS TAKES HOLD...AND
CLOUDS CLEAR...EXPECT TEMPS TO MIX OUT OVERNIGHT INTO THE MID 20S
ACROSS MUCH OF THE REGION. SUNNY SKIES WILL FINALLY MAKE AN
APPEARANCE DURING THE DAY TOMORROW AS HIGH PRESSURE REMAINS IN
CONTROL. TEMPERATURES WILL BE ON THE COOLER SIDE COMPARED TO
TODAY...BUT WILL STILL BE ABLE TO WARM UP TO ABOUT THE 40 DEGREE
MARK. NAM12 FORECAST SOUNDINGS SHOW THE ATMOSPHERE BECOMING QUITE
DRY...WITH DEW POINTS DROPPING SUBSTANTIALLY. THIS WILL ESPECIALLY
BE THE CASE IN THE HIGHER TERRAIN WEDNESDAY NIGHT...WHERE DEW POINTS
COULD DROP AS LOW AS 9 DEGREES. OVERNIGHT LOW TEMPS WILL DROP TO
AROUND FREEZING OR SLIGHTLY BELOW...WITH A GOOD SET UP FOR A RIDGE
VALLEY SPLIT TO OCCUR.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 415 AM EST TUE DEC 17 2013
THE EXTENDED FORECAST PERIOD BEGINS ON WEDNESDAY NIGHT WITH A MAINLY
ZONAL PATTERN OVER THE CONUS BUT IN TRANSITION. AN UPPER LEVEL LOW
COMES ASHORE OVER THE SOUTHWEST AND BAJA REGION AND BECOMES CUT OFF
BUT STILL INFLUENCE BY THE UPPER LEVEL FLOW AS IT CREEPS EASTWARD.
MEANWHILE...THE NORTHERN PORTION OF THE STREAM BRINGS A SEPARATE
SHORTWAVE INTO THE PLAINS AND INTO THE MS RIVER VALLEY BY FRIDAY.
THIS WILL LEAD TO LOW DEVELOPMENT AT THE SURFACE OVER THE UPPER MS
RIVER VALLEY AS A COLD FRONT BEGINS TO PUSH INTO THE OHIO VALLEY BY
FRIDAY NIGHT. THIS FRONT BECOMES STALLED OUT THANKS TO A STAUNCH
RIDGE OVER THE ATLANTIC OCEAN. THIS HAS BECOME A POINT OF CONCERN
OVER THE PAST SEVERAL DAYS OF THE MODEL RUNS AS THIS EVENT CONTINUES
TO TAKE SHAPE.
PRECIP SHOULD BEGIN TO ENTER THE AREA ON FRIDAY AND CONTINUE THROUGH
THE WEEKEND AS THE FRONT STALLS. PLENTY OF MOISTURE IS AVAILABLE AS
THIS SYSTEM DEVELOPS BUT MOST OF THE UPPER LEVEL DYNAMICS HAVE
ALREADY PASSED OFF TO THE NORTHEAST. HOWEVER...BY SATURDAY...THE
AFOREMENTIONED CLOSED LOW OVER THE SOUTHWEST FINALLY OPENS AND EJECTS
EASTWARD INTO THE LOWER MS RIVER VALLEY. THIS WILL HELP GENERATE
RAPID CYCLOGENESIS AT THE SURFACE OVER THE SOUTHERN PLAINS ALONG THE
STALLED FRONTAL BOUNDARY AS A DEEP LOW DEVELOPS. ABUNDANT MOISTURE
WILL THEN STREAM NORTHWARD AS A WARM FRONT MOVES NORTH INTO THE
LOWER OHIO VALLEY BY SATURDAY NIGHT. THE LOW LEVEL JET SETS UP WITH
50 TO 70 KNOTS TRANSPORTING WARM AIR AND AMPLE MOISTURE NORTHWARD.
THIS WILL BRING SOAKING RAINS OVER EASTERN KENTUCKY. THE WARM FRONT
WILL MOVE NORTH INTO OHIO BY SUNDAY MORNING AS A STRONG COLD FRONT
QUICKLY HEADS EAST INTO EASTERN KENTUCKY SUNDAY AFTERNOON. HERE IN
LIES A POSSIBLE FORECAST PROBLEM AS THE FRONT MOVES EAST QUITE
QUICKLY BUT MODELS KEEP THE HIGH OVER THE ATLANTIC THAT STALLED OUT
THE PREVIOUS FRONT BARELY WEAKENED OR CENTERED ANY FARTHER EAST. THE
EURO AND GFS HAVE COME INTO AGREEMENT KEEPING THE FRONT PROGRESSIVE
AND NOW HAVE A FEW RUNS OF CONSISTENCY SO WILL KEEP THE QUICKER EXIT
BUT THIS WILL BE AN ELEMENT OF THE FORECAST TO WATCH CLOSELY. THIS
TIME OF YEAR...AND WITH THE MOISTURE THIS SYSTEM HAS TO WORK
WITH...A STALLED BOUNDARY WOULD CERTAINLY CAUSE FLOODING TO BE A
CONCERN.
THE FRONT MOVES THROUGH THE AREA BY MONDAY MORNING WITH THE COLDER
AIR ADVECTING INTO EASTERN KENTUCKY IN STRONG NORTHWEST FLOW. A WEAK
WAVE BEHIND THE FRONT WILL SLIDE SOUTHEAST BRINGING JUST ENOUGH
MOISTURE FOR SOME RAIN CHANGING TO SNOW BEHIND THE FRONT. WIND FLOW
IS ALSO JUST ABOUT FAVORABLE FOR UPSLOPE TYPE SNOWFALLS. THE DEPTH
OF MOISTURE IS IN QUESTION BEHIND THE FRONT SO ANY SNOWFALL MAY ALSO
BE SHORT IN DURATION AND CONFINED TO THE BLUEGRASS COUNTIES AS TEMPS
MAY NOT DROP OFF FAST ENOUGH BEFORE ALL THE LIST AND MOISTURE EXIT
EASTERN KENTUCKY BY MONDAY EVENING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1259 PM EST TUE DEC 17 2013
LOW CIGS CONTINUE ACROSS THE NORTHER CWA AS A SHORTWAVE CONTINUES TO
MOVE ACROSS THE REGION. THIS HAS PRODUCED A LINE OF WEAK SHOWERS
MAINLY NORTH OF THE MOUNTAIN PARKWAY...POSING LITTLE THREAT TO VIS.
THE ONLY TAF SITE WHICH MAY POSSIBLY BE IMPACTED BY THIS RAIN IS
KSJS...BUT IMPACTS WILL BE MINIMAL. AS WE CONTINUE THROUGHOUT THE
EVENING...EXPECT THE SHORTWAVE TO SHIFT SE...BRINGING INCREASING POPS
TO THE FAR SE COUNTIES...MAINLY ALONG THE VA AND WV BORDER. AS
TEMPERATURES FALL THROUGHOUT THE EVENING...THIS PRECIPITATION WILL
CHANGE OVER TO SNOW. BUT ONCE AGAIN...THE ONLY TAF SITE WHICH SHOULD
FEEL ANY IMPACTS FROM THIS WILL BE KSJS. DROPPED THE CIGS AT KSJS TO
MVFR AS THE PRECIPITATION MOVES THROUGH...BEFORE CLEARING OUT LATE
TONIGHT AS HIGH PRESSURE MOVES IN OVERHEAD. FOR THE REMAINING TAF
SITES...SOME LOW CLOUDS MAY BE FELT LATER IN THE EVENING AS THE
SHORTWAVE MOVES SE ACROSS THE AREA. HOWEVER...BASED ON LATEST NAM12
AND GFSLAMP DATA...THESE CLOUDS SHOULD STAY RIGHT AT OR SLIGHTLY
ABOVE THE VFR RANGE...BEFORE CLEARING OUT LATE TONIGHT.
AS FAR AS WINDS...HIGH PRESSURE GRADIENTS ACROSS THE REGION TODAY AND
THIS EVENING SHOULD LEAD TO SOME POSSIBLE GUSTS IN THE 15 TO 20KT
RANGE. UNFORTUNATELY...RECENT OBSERVATIONS HAVE NOT SHOWN THIS
MATERIALIZING AS WELL...THOUGH THE POTENTIAL IS MOST CERTAINLY
STILL THERE. WENT AHEAD AND KEPT WINDS AT 10KTS OR SO...BUT DID TAKE
OUT GUSTS THROUGH THIS EVENING. AS MENTIONED ABOVE...WILL CONTINUE TO
MONITOR THIS AS WELL IN CASE CHANGES NEED TO BE MADE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JMW
LONG TERM...SHALLENBERGER
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
102 PM EST TUE DEC 17 2013
.UPDATE...
ISSUED AT 1259 PM EST TUE DEC 17 2013
THE SHORTWAVE THAT WAS ORIGINALLY SUPPOSED TO MOVE JUST TO OUR NORTH
AS OF YESTERDAY...DROPPED FURTHER SOUTH OVERNIGHT...BRINGING THE
POTENTIAL FOR HIGHER RAIN CHANCES AND SNOWFALL TOTALS ONCE
TEMPERATURES DROPPED BELOW FREEZING. GRIDS WERE UPDATED ACCORDINGLY.
HOWEVER...BASED ON LATEST HI-RES MODEL TRENDS...IN CONJUNCTION WITH
LATEST RADAR AND SATELLITE IMAGERY...ALTHOUGH THE SHORTWAVE PATTERN
REMAINS THE SAME...THE AMOUNT OF MOISTURE AND IMPACTS IS JUST MUCH
LOWER THAN ANTICIPATED. SINCE THE LATEST HRRR WAS INITIALIZING THE
BEST WITH ONGOING CONDITIONS...USED TO BLEND IN WITH THE ONGOING
FORECAST...AS WELL AS THE LATEST NAM12 AND ECMWF /ALL OF WHICH WERE
SHOWING SIMILAR LIGHTER SOLUTIONS/. WITH THIS IDEA...BEST PRECIP WILL
FALL ACROSS THE NORTHERN CWA THROUGHOUT THE EARLY AFTERNOON IN THE
FORM OF RAIN...WITH TEMPS WELL ABOVE FREEZING. BY LATER THIS
EVENING...THE SHORTWAVE WILL SHIFT SE...BRINGING BEST PRECIP CHANCES
ALONG THE FAR SERN COUNTIES NEAR THE VA AND WV BORDER. WHILE
TEMPERATURES WILL STILL SUPPORT SNOW DEVELOPMENT...THE IMPACTS WILL
BE MUCH LESS THAN ORIGINALLY CALLED FOR ON THE PREVIOUS SHIFT. ONLY A
DUSTING OR LESS IS EXPECTED IN MOST PLACES...WITH SOME OF THE HIGHER
TERRAIN POSSIBLY PICKING UP AROUND A HALF OF AN INCH OF SO. BLACK
MOUNTAIN IS FORECAST TO SEE THE HIGHEST AMOUNTS...BUT STILL ONLY
RIGHT AROUND AN INCH. SINCE UPDATES WERE MADE TO REFLECT THIS
THINKING...RADAR TRENDS CONTINUE TO SUPPORT THIS LOWERING OF QPF AND
POPS. BUT AS ALWAYS...WILL CONTINUE TO MONITOR LATEST MODEL DATA AND
ONGOING CONDITIONS IN CASE ANY UPDATES NEED TO BE MADE.
UPDATE ISSUED AT 645 AM EST TUE DEC 17 2013
A COMPLEX TEMPERATURE PATTERN REMAINS AS WE APPROACH DAWN. MANY
LOCATIONS HAVE WARMED TO THE UPPER 30S TO LOW TO MID 40S OUTSIDE OF
THE HIGH TERRAIN IN THE WARM AIR ADVECTION AHEAD OF THE APPROACHING
COLD FRONT. MEANWHILE...KI35 AND K1A6 ARE NEAR THE 30 DEGREE MARK AS
THOSE VALLEY LOCATIONS HAVE NOT BEEN SCOURED OUT. HOWEVER...THIS
FRONT IS MOVING ACROSS THE FAR NW COUNTIES AT THIS TIME AND HAS
PASSED THROUGH FFT...AND IS NEARING LEX. THIS SHOULD LEAD TO ONLY A
COUPLE OF MORE DEGREE RISE IN MANY LOCATIONS...IF THAT WITH TEMPERATURES
LIKELY REMAINING RATHER FLAT THROUGH THE MORNING AND THEN SLOWLY
TAILING OFF IN THE AFTERNOON THROUGH EARLY EVENING WITH COLD AIR
ADVECTION KICKING IN AND IN RAIN OR MIXED RAIN AND SNOW SHOWERS MOVING
THROUGH THE AREA. THE 6Z GFS BACKED AWAY A LITTLE ON THE QPF IN THE
NORTHEASTERN COUNTIES FOR THIS AFTERNOON AND THE ASSOCIATED MOS IS
SLOWER WITH THE COOLING. THESE TRENDS WILL CONTINUE TO BE MONITORED.
HOWEVER...SOME ACCUMULATION ON GRASSY AND ELEVATED SURFACES STILL
APPEARS POSSIBLE BY LATE AFTERNOON AND INTO THE EVENING AS LINGER
ISOLATED TO NUMEROUS RAIN SHOWERS CHANGE OVER TO SNOW SHOWERS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 350 AM EST TUE DEC 17 2013
THE REGION CONTINUES IN NORTHWEST FLOW ALOFT BETWEEN A RIDGE OF HIGH
PRESSURE OVER MEXICO AND EXTENDING NORTH ALONG THE US WEST COAST AND
A TROUGH EXTENDING SOUTH INTO THE GREAT LAKES...OH VALLEY REGION...AND
THE SOUTHEAST FROM A CLOSED LOW OVER ONTARIO. ONE SHORTWAVE TROUGH IS
CURRENTLY WORKING ACROSS THE OH VALLEY WITH MAINLY MID AND HIGH
CLOUDS AND VIRGA WITH ANOTHER MORE POTENT UPSTREAM SHORTWAVE WORKING
FROM MN INTO WI. AT THE SFC...AN AREA OF LOW PRESSURE IS TRACKING
INTO THE GREAT LAKES REGION WITH A TRAILING COLD FRONT EXTENDING DOWN
TO THE OH VALLEY...WHICH CROSSES NORTHEASTERN KY DOWN INTO WEST
CENTRAL KY AND ON INTO WESTERN TN ATTM. FURTHER UPSTREAM...A SFC HIGH
WAS IN PLACE ACROSS THE CENTRAL PLAINS REGION.
BANDS OF CLOUDS CONTINUE TO MOVE ACROSS THE REGION...BUT THESE ARE
MAINLY MID AND HIGH LEVEL CLOUDS SO FAR AHEAD OF A COLD FRONT.
SOUTHWEST FLOW AHEAD OF FRONT HAS BROUGHT UP INTO THE LOWER TO MID 40S
ACROSS WESTERN PARTS OF THE AREA AND ON SOME RIDGETOPS IN THE LOWER
TERRAIN...WHILE SOME LOWER 30S ARE CURRENTLY OBSERVED IN THE NON
SCOURED OUT SHELTERED VALLEYS TO THE EAST OF INTERSTATE 75 AND TO THE
SOUTH OF INTERSTATE 64.
LOW CLOUDS SHOULD MOVE BACK IN OR DEVELOP AROUND DAWN...ESPECIALLY
ACROSS NORTHERN SECTIONS BEHIND THE BOUNDARY AND LINGER INTO THE DAY
ON TUESDAY. THE COLD FRONT SHOULD NEARLY BISECT THE CWA NORTHWEST TO
SOUTHEAST AROUND DAWN...WITH THE BOUNDARY DEPARTING TO THE SOUTH OF
EASTERN KY AROUND MIDDAY.
A RATHER POTENT SHORTWAVE IS EXPECTED TO DIG INTO THE OHIO VALLEY AND
GREAT LAKES TO CENTRAL APPALACHIAN REGION ON TUESDAY. GFS 0Z MODEL
DATA INDICATES GOOD DEPTH WITH THIS SHORTWAVE AS EVIDENCED BY PV15
PRESSURE DOWN TO 550 MB AND EVEN LOWER IN THE ATMOSPHERE AS IT MOVES
INTO THE CENTRAL APPALACHIANS. WITH THIS IN MIND...HAVE OPTED TO
INCREASE POPS FROM THE INHERITED FORECAST ACROSS THE BOARD FOR
TUESDAY AFTERNOON INTO THE EVENING...AS THE WAVE MOVES THROUGH.
PRECIPITATION FOR THIS WOULD GENERALLY BE ALL RAIN INITIALLY...BUT IN
ANY CONVECTION AND DEEPER OMEGA...TEMPS WOULD HAVE THE OPPORTUNITY TO
COOL OFF ENOUGH FOR PRECIPITATION TO CHANGE OVER TO SNOW BY LATE
AFTERNOON OR EVENING...POSSIBLY AFFECTING THE EVENING COMMUTE. QPF ON
AVERAGE WITH THIS SYSTEM SHOULD GENERALLY BE A TENTH OF AN INCH OR
LESS...THOUGH LOCALLY HIGHER AMOUNTS COULD OCCUR IN ANY STRONGER
SHOWERS. INITIALLY WARM GROUND WOULD BE A LIMITING FACTOR TO ANY
ACCUMULATIONS AS WELL AS TIME OF DAY. HOWEVER...A DUSTING TO A HALF
OF AN INCH COULD CERTAINLY OCCUR ON THE RIDGETOPS ANY IN ANY LOCALLY
HEAVIER SNOW SHOWERS DURING THE LATE AFTERNOON INTO THE EVENING.
WINDS WILL ALSO BE GUSTY IN THE AFTERNOON IN THE SHOWERS...WITH 10 TO
15 MPH SUSTAINED COMMON...WITH GUSTS AROUND 25 MPH AT TIMES.
HOURLY TEMPERATURES AND MAX TEMPS FOR TUE HAVE BEEN ADJUSTED TO
ACCOUNT FOR RECENT TRENDS AND ANTICIPATED TRENDS ON TUE AS SHOWERS
MOVE THROUGH AND THE ANTICIPATED COLD AIR ADVECTION LATE IN THE DAY.
HIGH PRESSURE WILL BUILD IN AT THE SFC AND ALOFT TO END THE PERIOD...ON
WED AND DRY WEATHER IS ANTICIPATED AS THE SFC HIGH SHOULD SETTLE
ACROSS THE CENTRAL APPALACHIANS BY THE END OF THE PERIOD.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 415 AM EST TUE DEC 17 2013
THE EXTENDED FORECAST PERIOD BEGINS ON WEDNESDAY NIGHT WITH A MAINLY
ZONAL PATTERN OVER THE CONUS BUT IN TRANSITION. AN UPPER LEVEL LOW
COMES ASHORE OVER THE SOUTHWEST AND BAJA REGION AND BECOMES CUT OFF
BUT STILL INFLUENCE BY THE UPPER LEVEL FLOW AS IT CREEPS EASTWARD.
MEANWHILE...THE NORTHERN PORTION OF THE STREAM BRINGS A SEPARATE
SHORTWAVE INTO THE PLAINS AND INTO THE MS RIVER VALLEY BY FRIDAY.
THIS WILL LEAD TO LOW DEVELOPMENT AT THE SURFACE OVER THE UPPER MS
RIVER VALLEY AS A COLD FRONT BEGINS TO PUSH INTO THE OHIO VALLEY BY
FRIDAY NIGHT. THIS FRONT BECOMES STALLED OUT THANKS TO A STAUNCH
RIDGE OVER THE ATLANTIC OCEAN. THIS HAS BECOME A POINT OF CONCERN
OVER THE PAST SEVERAL DAYS OF THE MODEL RUNS AS THIS EVENT CONTINUES
TO TAKE SHAPE.
PRECIP SHOULD BEGIN TO ENTER THE AREA ON FRIDAY AND CONTINUE THROUGH
THE WEEKEND AS THE FRONT STALLS. PLENTY OF MOISTURE IS AVAILABLE AS
THIS SYSTEM DEVELOPS BUT MOST OF THE UPPER LEVEL DYNAMICS HAVE
ALREADY PASSED OFF TO THE NORTHEAST. HOWEVER...BY SATURDAY...THE
AFOREMENTIONED CLOSED LOW OVER THE SOUTHWEST FINALLY OPENS AND EJECTS
EASTWARD INTO THE LOWER MS RIVER VALLEY. THIS WILL HELP GENERATE
RAPID CYCLOGENESIS AT THE SURFACE OVER THE SOUTHERN PLAINS ALONG THE
STALLED FRONTAL BOUNDARY AS A DEEP LOW DEVELOPS. ABUNDANT MOISTURE
WILL THEN STREAM NORTHWARD AS A WARM FRONT MOVES NORTH INTO THE
LOWER OHIO VALLEY BY SATURDAY NIGHT. THE LOW LEVEL JET SETS UP WITH
50 TO 70 KNOTS TRANSPORTING WARM AIR AND AMPLE MOISTURE NORTHWARD.
THIS WILL BRING SOAKING RAINS OVER EASTERN KENTUCKY. THE WARM FRONT
WILL MOVE NORTH INTO OHIO BY SUNDAY MORNING AS A STRONG COLD FRONT
QUICKLY HEADS EAST INTO EASTERN KENTUCKY SUNDAY AFTERNOON. HERE IN
LIES A POSSIBLE FORECAST PROBLEM AS THE FRONT MOVES EAST QUITE
QUICKLY BUT MODELS KEEP THE HIGH OVER THE ATLANTIC THAT STALLED OUT
THE PREVIOUS FRONT BARELY WEAKENED OR CENTERED ANY FARTHER EAST. THE
EURO AND GFS HAVE COME INTO AGREEMENT KEEPING THE FRONT PROGRESSIVE
AND NOW HAVE A FEW RUNS OF CONSISTENCY SO WILL KEEP THE QUICKER EXIT
BUT THIS WILL BE AN ELEMENT OF THE FORECAST TO WATCH CLOSELY. THIS
TIME OF YEAR...AND WITH THE MOISTURE THIS SYSTEM HAS TO WORK
WITH...A STALLED BOUNDARY WOULD CERTAINLY CAUSE FLOODING TO BE A
CONCERN.
THE FRONT MOVES THROUGH THE AREA BY MONDAY MORNING WITH THE COLDER
AIR ADVECTING INTO EASTERN KENTUCKY IN STRONG NORTHWEST FLOW. A WEAK
WAVE BEHIND THE FRONT WILL SLIDE SOUTHEAST BRINGING JUST ENOUGH
MOISTURE FOR SOME RAIN CHANGING TO SNOW BEHIND THE FRONT. WIND FLOW
IS ALSO JUST ABOUT FAVORABLE FOR UPSLOPE TYPE SNOWFALLS. THE DEPTH
OF MOISTURE IS IN QUESTION BEHIND THE FRONT SO ANY SNOWFALL MAY ALSO
BE SHORT IN DURATION AND CONFINED TO THE BLUEGRASS COUNTIES AS TEMPS
MAY NOT DROP OFF FAST ENOUGH BEFORE ALL THE LIST AND MOISTURE EXIT
EASTERN KENTUCKY BY MONDAY EVENING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1259 PM EST TUE DEC 17 2013
LOW CIGS CONTINUE ACROSS THE NORTHER CWA AS A SHORTWAVE CONTINUES TO
MOVE ACROSS THE REGION. THIS HAS PRODUCED A LINE OF WEAK SHOWERS
MAINLY NORTH OF THE MOUNTAIN PARKWAY...POSING LITTLE THREAT TO VIS.
THE ONLY TAF SITE WHICH MAY POSSIBLY BE IMPACTED BY THIS RAIN IS
KSJS...BUT IMPACTS WILL BE MINIMAL. AS WE CONTINUE THROUGHOUT THE
EVENING...EXPECT THE SHORTWAVE TO SHIFT SE...BRINGING INCREASING POPS
TO THE FAR SE COUNTIES...MAINLY ALONG THE VA AND WV BORDER. AS
TEMPERATURES FALL THROUGHOUT THE EVENING...THIS PRECIPITATION WILL
CHANGE OVER TO SNOW. BUT ONCE AGAIN...THE ONLY TAF SITE WHICH SHOULD
FEEL ANY IMPACTS FROM THIS WILL BE KSJS. DROPPED THE CIGS AT KSJS TO
MVFR AS THE PRECIPITATION MOVES THROUGH...BEFORE CLEARING OUT LATE
TONIGHT AS HIGH PRESSURE MOVES IN OVERHEAD. FOR THE REMAINING TAF
SITES...SOME LOW CLOUDS MAY BE FELT LATER IN THE EVENING AS THE
SHORTWAVE MOVES SE ACROSS THE AREA. HOWEVER...BASED ON LATEST NAM12
AND GFSLAMP DATA...THESE CLOUDS SHOULD STAY RIGHT AT OR SLIGHTLY
ABOVE THE VFR RANGE...BEFORE CLEARING OUT LATE TONIGHT.
AS FAR AS WINDS...HIGH PRESSURE GRADIENTS ACROSS THE REGION TODAY AND
THIS EVENING SHOULD LEAD TO SOME POSSIBLE GUSTS IN THE 15 TO 20KT
RANGE. UNFORTUNATELY...RECENT OBSERVATIONS HAVE NOT SHOWN THIS
MATERIALIZING AS WELL...THOUGH THE POTENTIAL IS MOST CERTAINLY
STILL THERE. WENT AHEAD AND KEPT WINDS AT 10KTS OR SO...BUT DID TAKE
OUT GUSTS THROUGH THIS EVENING. AS MENTIONED ABOVE...WILL CONTINUE TO
MONITOR THIS AS WELL IN CASE CHANGES NEED TO BE MADE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...JP
LONG TERM...SHALLENBERGER
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
457 PM EST TUE DEC 17 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 343 PM EST TUE DEC 17 2013
NOTE THAT TEMPS AT CMX REMAIN QUESTIONABLE DUE TO FAULTY FAN ON
OBSERVATION EQUIPMENT. TECHNICIANS WL BE WORKING ON THIS PROBLEM
TMRW.
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT NW FLOW
ALF BTWN DEEP UPR TROF CENTERED OVER ONTARIO AND UPR RDG OVER WRN
NAMERICA. H5 TEMPS WITHIN THE TROF EXTENDING INTO THE GREAT LKS ARE
AS LO AS -40C...SO THE AREA REMAINS IN THE GRIP OF WINTER CHILL. ONE
SHRTWV EMBEDDED WITHIN THE UPR TROF BROUGHT SOME -SN TO THE SCNTRL
CWA THIS MRNG...BUT THIS DISTURBANCE/DEEPER MSTR SHOWN ON THE 12Z
GRB RAOB HAVE SHIFTED TO THE E. ANOTHER SHRTWV IS PRESENT OVER MN...
BUT THIS DISTURBANCE WL BE PASSING TOO FAR TO THE S TO HAVE AN
IMPACT ON UPR MI. YET ANOTHER SHRTWV IS OVER NW ONTARIO AND DROPPING
SEWD. ATTENDANT SFC-H85 COLD FNT MOVED INTO WRN UPR MI THIS AFTN.
12Z INL/YPL RAOBS SHOW HI RELATIVE RH TO H6-5 AND 12Z H85 TEMPS
RANGING FM -13C AT INL RIGHT BEHIND THE COLD FNT TO -24C AT YPL...
WHICH WAS DEEPER INTO THE COLD AIRMASS. SO THERE ARE POCKETS OF SHSN
EXTENDING UPWIND OF LK SUP IN NRN MN/ADJOINING ONTARIO. FARTHER TO
THE W...THERE ARE SIGNS THE FLOW IS BECOMING A BIT MORE
PROGRESSIVE...AT LEAST FOR A SHORT TIME. 00Z-12Z H3 HGT RISES UP TO
150M WERE REPORTED AT SEVERAL UPR AIR SITES FM THE NRN PLAINS INTO
SCNTRL CANADA AS THE WRN RDG SHIFTS TO THE E.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON LES POPS/AMOUNTS WITH
ARRIVAL OF MORE ARCTIC AIR BEHIND EARLY AFTN/EARLY EVNG COLD FROPA.
TNGT...SHRTWV IN NW ONTARIO IS FCST TO SHIFT SEWD ACRS NRN LK SUP...
ACCOMPANIED BY AREA OF WEAK H85-5 QVECTOR CNVGC/SOME DEEPER MSTR AND
ATTENDANT COLD FROPA. EXPECT SHSN INTENSITY/COVERAGE TO INCRS LATE
THIS AFTN/EVNG W-E...ESPECIALLY IN AREAS NEAR LK SUP FAVORED BY THE
WNW FLOW IN THE WAKE OF THE COLD FROPA...WHICH WL BE FOLLOWED BY
AXIS OF H85 TEMPS AS LO AS -20C. ALTHOUGH NOT OUT OF THE QUESTION
THERE COULD BE SOME HEAVIER SHSN IN THE FAVORED SN BELTS...ADVY SN
SEEMS UNLIKELY. THE FIRST LIMITING FACTOR WL BE RELATIVELY SHORT
DURATION OF THE HEAVIER LES. HGT RISES NOTED IN THE NRN PLAINS/
SCENTRAL CANADA ARE PROGGED TO FOLLOW QUICKLY THE DEPARTING SHRTWV
LATER IN THE EVNG WITH VIGOUROUS DNVA/DEEP LYR QVECTOR DVGC LOWERING
SUBSIDENCE INVRN TO NEAR 3K FT OVER THE KEWEENAW BY 12Z. APRCH OF
SFC RDG AXIS AND SHIFTING LLVL WINDS OVER THE W UNDER THESE NEGATIVE
DYNAMICS...WITH RDG AXIS ARRIVING THERE BY 12Z...WL ALSO ACT TO
SUPPRESS THE SN AMOUNTS. IN FACT...SUITE OF HIER RES MODEL OUTPUT IS
QUITE VARIABLE ON QPF...WITH FCSTS INCONSISTENT ON MAGNITUDE/HGT/
TIMING OF SHARPER UVV AND RELATIVE TO THE DGZ. IN THE NW WIND SN
BELTS TO THE E OF MQT...SHSN WL ARRIVE DURING THE EVNG AND PERSIST
THRU 12Z. LONGER FETCH OVER THE OPEN WATER WL PLAY AN ENHANCEMENT
ROLE IN INTENSIFYING THE SHSN STREAMING INTO THIS AREA...BUT
SHIFTING WINDS MAY LIMIT THE RESIDENCE TIME OF THE HEAVIER SHSN HERE
AS WELL. THE MOST FAVORABLE FACTOR FOR HEAVIER SN OVER THE ERN CWA
NEAR LK SUP WL BE THE POTENTIAL FOR LAND BREEZE CNVGC OVER FAR
EASTERN ALGER/NRN LUCE COUNTIES. BUT FCST SDNGS SHOW SUBSIDENCE
INVRN SINKING FAIRLY STEADY HERE AS WELL LATER AT NGT WHEN THE
POTENTIAL FOR THE SHARPER LLVL CNVGC WOULD BE GREATER. AS IS
TYPICAL...AREAS OVER THE SCENTRAL WL SEE NOTHING MORE THAN ISOLD
-SHSN WITH DOWNSLOPE FLOW. EXPECT THE LOWEST MIN TEMPS OVER THE
INTERIOR W...WHERE THERE WL BE SOME CLRG/LIGHT WINDS WITH ARRIVAL OF
SFC RDG AXIS.
WED...AS THE UPR FLOW TENDS TO SHIFT MORE ZONAL...A SHRTWV IS FCST
TO SHIFT E THRU SCENTRAL CANADA...WITH ASSOCIATED SFC LO PRES FCST
TO MOVE INTO NRN MN BY 00Z THU. GENERAL WAD/ISENTROPIC LIFT BTWN
THIS SHRTWV/SFC LO AND SFC HI SHIFTING INTO THE SE CONUS WL IMPACT
THE UPR GRT LKS. AS THE FLOW BACKS TO THE SW...LINGERING LES OVER
THE KEWEENAW AND FAR E CWA NEAR LK SUP WL SHIFT OUT INTO THE OPEN
LK. THE BULK OF THE MODELS SHOW LGT SN ASSOCIATED WITH THE SHARPER
ISENTROPIC ASCENT FALLING OVER LK SUP. THE CNDN MODEL IS THE ONE
EXCEPTION...AS THIS MODEL SHOWS THE SFC LO A BIT FARTHER S IN MN AND
STRIPE OF LGT -SN IMPACTING APPROXIMATELY THE NE HALF OF THE CWA.
GIVEN PERSISTENCE OF TROF IN ERN CANADA AND CHILL...SUSPECT THIS
MODEL IS ON THE RIGHT TRACK. SO WL SHIFT THE AXIS OF CHC POPS A BIT
TO THE SW INTO THE NRN LAND CWA. FEED OF RELATIVELY DRY LLVL AIR WL
LIMIT ANY POTENTIAL SN ACCUM EVEN IF THE MORE PESSIMISTIC CNDN MODEL
DOES VERIFY. ALSO LOWERED FCST MAX TEMPS A BIT TO REFLECT THE
POTENTIAL FOR MORE TENACIOUS COLD LLVL AIR.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 457 PM EST TUE DEC 17 2013
MUCH OF THIS FCST PERIOD IS IN THE MODERATE TO LOWER CONFIDENCE
RANGE.
AT 00Z THURSDAY MUCH OF THE CONTINENTAL U.S. WILL BE UNDER A BROAD
WEAK RIDGE TO ZONAL FLOW AT 500MB...WITH THE DOMINANT LOW SPINNING
ACROSS N CANADA WITH LONGWAVE TROUGHS EXTENDING ACROSS BOTH THE WEST
AND EAST COASTS.
AN INITIAL BROAD SFC LOW/TROUGH WILL EXTEND NE INTO CENTRAL LAKE
SUPERIOR AT 00Z. WHILE THE GFS PUSHES THE LOW E OF LAKE SUPERIOR BY
06Z THURSDAY...THE ECMWF KEEPS IT AS PART OF THE MAIN SYSTEM TO OUR
S. THE RESULT IS A COMPLETELY DIFFERENT FCST FOR WEDNESDAY
NIGHT...WITH LES OFF THE GFS ON STRONGER NW WINDS...WHILE THE ECMWF
SOLUTION KEEPS A WAA SCHEME OVER THE AREA A BIT LONGER. THEY BOTH DO
AGREE WITH SOME SORT OF LAKE ENHANCEMENT N OR NW FLOW BY THURSDAY
AFTERNOON...ALTHOUGH THE GFS IS APPROX 2C COOLER NEAR THE SFC.
LOOK FOR THE CANADIAN AND W COAST SYSTEMS TO DEEPEN AS THEY SINK SSE
THURSDAY AND FRIDAY. AT 18Z THURSDAY THE MAIN TROUGH WILL EXTEND
FROM THE S LOW OVER S CA UP THROUGH MT INTO S CANADA.
A QUICK BURST OF SNOW THURSDAY NIGHT LOOKS TO BE ABOUT IT...EXCEPT
FOR SOME LAKE EFFECT/LAKE ENHANCEMENT ON W TO NW WINDS OVER THE
KEWEENAW PENINSULA...AND AROUND AND E OF MUNISING THROUGH ABOUT MID
MORNING FRIDAY. TOTAL SNOWFALL OF 1-2IN STILL LOOK GOOD. CONFIDENCE
REMAINS LOW WITH THIS SYSTEM. THE 12Z NAM DID NOT REALLY BRING ANY
OF THE SYNOPTIC MOISTURE INTO UPPER MI...ALTHOUGH THE 18Z VERSION
BROUGHT SNOW BACK NW SIMILARLY TO THE GFS. WILL STILL HIGHLIGHT THE
POTENTIAL FOR A FEW INCHES OF SNOW LATE THURSDAY AFTERNOON INTO
FRIDAY MORNING...MAINLY OVER THE HIGHER TERRAIN NEAR LAKE SUPERIOR.
THE NEXT LOW OVER THE ROCKIES SATURDAY WILL EJECT NE SUNDAY...WITH
UPPER MI AGAIN ON THE BACK SIDE OF THE LOW. GIVEN THE STRENGTH OF
THE SYSTEM...AND SIGNIFICANT HIGH DROPPING IN FROM THE NW SUNDAY
THROUGH MONDAY...MUCH COLDER AIR WILL BE ABLE TO SLIDE IN. 850MB
TEMPS OF -20 TO -22C WILL BE POSSIBLE. THERE ARE SOME TIMING
DIFFERENCES BETWEEN THE GFS AND ECMWF AT THIS PERIOD...BUT THEY ARE
CONSISTENT WITH THE COLD AIR.
FARTHER OUT...EXPECT STRONG WAA TUESDAY BEHIND THE COLD AIRMASS.
WHILE TIMING IS STILL IN QUESTION...SW 40-55KT 850MB WINDS WITH SFC
WINDS OF 15-25KTS LOOK LIKELY FOR A 6HR WINDOW BETWEEN 09Z TUESDAY
TO 00Z WEDNESDAY. WILL NEED TO MONITOR MODEL TRENDS TO ADD MORE
SPECIFICITY AS THE TIME NEARS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1225 PM EST TUE DEC 17 2013
AS A COLD FNT/AREA OF DEEPER MSTR SURGE ACROSS UPR MI THIS AFTN/
EVNG...EXPECT A PERIOD OF IFR CONDITIONS TO IMPACT IWD AND
ESPECIALLY CMX...WHERE SHARPER UPSLOPE WIND COMPONENT/GREAT EXPOSURE
TO FCST WNW WIND WL ENHANCE THE SHSN/BLSN AND POTENTIAL FOR LOWER
CIGS. SAW MAY SEE MVFR CONDITIONS WITH A DOWNSLOPE WIND COMPONENT
LIMITING THE POTENTIAL FOR LOWER CONDITIONS. THE APRCH OF A HI PRES
RDG AXIS/DRIER AIR LATER TNGT WL CAUSE IMPROVING WX...WITH
CONDITIONS IMPROVING TO VFR LATER TNGT W-E FOLLOWING THE PASSAGE OF
RDG AXIS WSHFT TO THE SW. A MORE PERSISTENT UPSLOPE WIND COMPONENT
WL SLOW THE IMPROVEMENT AT CMX.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 343 PM EST TUE DEC 17 2013
EXPECT NW WINDS TO 25-30 KTS THIS EVENING BEHIND A COLD FRONTAL
PASSAGE TO DIMINISH AND BACK TO THE SW WITH APPROACH OF A HI PRES
RIDGE LATER TONIGHT INTO WED. A VERY CHANGEABLE WEATHER PATTERN WILL
THEN DOMINATE THE UPPER GREAT LAKES THE REST OF THE WEEK...WITH HARD
TO TIME DISTURBANCES IMPACTING LAKE SUPERIOR. CONFIDENCE IS LOW IN
TIMING THESE DISTURBANCES AND ACCOMPANYING WIND SHIFTS...BUT GALES
APPEAR UNLIKELY THRU THE FORECAST PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
344 PM EST TUE DEC 17 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 343 PM EST TUE DEC 17 2013
NOTE THAT TEMPS AT CMX REMAIN QUESTIONABLE DUE TO FAULTY FAN ON
OBSERVATION EQUIPMENT. TECHNICIANS WL BE WORKING ON THIS PROBLEM
TMRW.
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT NW FLOW
ALF BTWN DEEP UPR TROF CENTERED OVER ONTARIO AND UPR RDG OVER WRN
NAMERICA. H5 TEMPS WITHIN THE TROF EXTENDING INTO THE GREAT LKS ARE
AS LO AS -40C...SO THE AREA REMAINS IN THE GRIP OF WINTER CHILL. ONE
SHRTWV EMBEDDED WITHIN THE UPR TROF BROUGHT SOME -SN TO THE SCNTRL
CWA THIS MRNG...BUT THIS DISTURBANCE/DEEPER MSTR SHOWN ON THE 12Z
GRB RAOB HAVE SHIFTED TO THE E. ANOTHER SHRTWV IS PRESENT OVER MN...
BUT THIS DISTURBANCE WL BE PASSING TOO FAR TO THE S TO HAVE AN
IMPACT ON UPR MI. YET ANOTHER SHRTWV IS OVER NW ONTARIO AND DROPPING
SEWD. ATTENDANT SFC-H85 COLD FNT MOVED INTO WRN UPR MI THIS AFTN.
12Z INL/YPL RAOBS SHOW HI RELATIVE RH TO H6-5 AND 12Z H85 TEMPS
RANGING FM -13C AT INL RIGHT BEHIND THE COLD FNT TO -24C AT YPL...
WHICH WAS DEEPER INTO THE COLD AIRMASS. SO THERE ARE POCKETS OF SHSN
EXTENDING UPWIND OF LK SUP IN NRN MN/ADJOINING ONTARIO. FARTHER TO
THE W...THERE ARE SIGNS THE FLOW IS BECOMING A BIT MORE
PROGRESSIVE...AT LEAST FOR A SHORT TIME. 00Z-12Z H3 HGT RISES UP TO
150M WERE REPORTED AT SEVERAL UPR AIR SITES FM THE NRN PLAINS INTO
SCNTRL CANADA AS THE WRN RDG SHIFTS TO THE E.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON LES POPS/AMOUNTS WITH
ARRIVAL OF MORE ARCTIC AIR BEHIND EARLY AFTN/EARLY EVNG COLD FROPA.
TNGT...SHRTWV IN NW ONTARIO IS FCST TO SHIFT SEWD ACRS NRN LK SUP...
ACCOMPANIED BY AREA OF WEAK H85-5 QVECTOR CNVGC/SOME DEEPER MSTR AND
ATTENDANT COLD FROPA. EXPECT SHSN INTENSITY/COVERAGE TO INCRS LATE
THIS AFTN/EVNG W-E...ESPECIALLY IN AREAS NEAR LK SUP FAVORED BY THE
WNW FLOW IN THE WAKE OF THE COLD FROPA...WHICH WL BE FOLLOWED BY
AXIS OF H85 TEMPS AS LO AS -20C. ALTHOUGH NOT OUT OF THE QUESTION
THERE COULD BE SOME HEAVIER SHSN IN THE FAVORED SN BELTS...ADVY SN
SEEMS UNLIKELY. THE FIRST LIMITING FACTOR WL BE RELATIVELY SHORT
DURATION OF THE HEAVIER LES. HGT RISES NOTED IN THE NRN PLAINS/
SCENTRAL CANADA ARE PROGGED TO FOLLOW QUICKLY THE DEPARTING SHRTWV
LATER IN THE EVNG WITH VIGOUROUS DNVA/DEEP LYR QVECTOR DVGC LOWERING
SUBSIDENCE INVRN TO NEAR 3K FT OVER THE KEWEENAW BY 12Z. APRCH OF
SFC RDG AXIS AND SHIFTING LLVL WINDS OVER THE W UNDER THESE NEGATIVE
DYNAMICS...WITH RDG AXIS ARRIVING THERE BY 12Z...WL ALSO ACT TO
SUPPRESS THE SN AMOUNTS. IN FACT...SUITE OF HIER RES MODEL OUTPUT IS
QUITE VARIABLE ON QPF...WITH FCSTS INCONSISTENT ON MAGNITUDE/HGT/
TIMING OF SHARPER UVV AND RELATIVE TO THE DGZ. IN THE NW WIND SN
BELTS TO THE E OF MQT...SHSN WL ARRIVE DURING THE EVNG AND PERSIST
THRU 12Z. LONGER FETCH OVER THE OPEN WATER WL PLAY AN ENHANCEMENT
ROLE IN INTENSIFYING THE SHSN STREAMING INTO THIS AREA...BUT
SHIFTING WINDS MAY LIMIT THE RESIDENCE TIME OF THE HEAVIER SHSN HERE
AS WELL. THE MOST FAVORABLE FACTOR FOR HEAVIER SN OVER THE ERN CWA
NEAR LK SUP WL BE THE POTENTIAL FOR LAND BREEZE CNVGC OVER FAR
EASTERN ALGER/NRN LUCE COUNTIES. BUT FCST SDNGS SHOW SUBSIDENCE
INVRN SINKING FAIRLY STEADY HERE AS WELL LATER AT NGT WHEN THE
POTENTIAL FOR THE SHARPER LLVL CNVGC WOULD BE GREATER. AS IS
TYPICAL...AREAS OVER THE SCENTRAL WL SEE NOTHING MORE THAN ISOLD
-SHSN WITH DOWNSLOPE FLOW. EXPECT THE LOWEST MIN TEMPS OVER THE
INTERIOR W...WHERE THERE WL BE SOME CLRG/LIGHT WINDS WITH ARRIVAL OF
SFC RDG AXIS.
WED...AS THE UPR FLOW TENDS TO SHIFT MORE ZONAL...A SHRTWV IS FCST
TO SHIFT E THRU SCENTRAL CANADA...WITH ASSOCIATED SFC LO PRES FCST
TO MOVE INTO NRN MN BY 00Z THU. GENERAL WAD/ISENTROPIC LIFT BTWN
THIS SHRTWV/SFC LO AND SFC HI SHIFTING INTO THE SE CONUS WL IMPACT
THE UPR GRT LKS. AS THE FLOW BACKS TO THE SW...LINGERING LES OVER
THE KEWEENAW AND FAR E CWA NEAR LK SUP WL SHIFT OUT INTO THE OPEN
LK. THE BULK OF THE MODELS SHOW LGT SN ASSOCIATED WITH THE SHARPER
ISENTROPIC ASCENT FALLING OVER LK SUP. THE CNDN MODEL IS THE ONE
EXCEPTION...AS THIS MODEL SHOWS THE SFC LO A BIT FARTHER S IN MN AND
STRIPE OF LGT -SN IMPACTING APPROXIMATELY THE NE HALF OF THE CWA.
GIVEN PERSISTENCE OF TROF IN ERN CANADA AND CHILL...SUSPECT THIS
MODEL IS ON THE RIGHT TRACK. SO WL SHIFT THE AXIS OF CHC POPS A BIT
TO THE SW INTO THE NRN LAND CWA. FEED OF RELATIVELY DRY LLVL AIR WL
LIMIT ANY POTENTIAL SN ACCUM EVEN IF THE MORE PESSIMISTIC CNDN MODEL
DOES VERIFY. ALSO LOWERED FCST MAX TEMPS A BIT TO REFLECT THE
POTENTIAL FOR MORE TENACIOUS COLD LLVL AIR.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 355 AM EST TUE DEC 17 2013
OVERALL...THE GENERAL IDEA OF THE LONG TERM PERIOD IS SIMILAR TO
WHAT WAS SEEN 24 HOURS AGO.
TO START THE PERIOD WEDNESDAY MORNING...LAKE EFFECT SNOW WILL BE
ONGOING OVER CENTRAL AND EASTERN LAKE SUPERIOR...WITH THE MAIN
AREAS SEEING SNOW BEING THE KEWEENAW PENINSULA AND AREAS EAST OF
MUNISING NEAR LAKE SUPERIOR. BUT WITH A HIGH PRESSURE RIDGE SLIDING
ACROSS SOUTHERN UPPER MICHIGAN...WINDS WILL BE BACKING TO THE
SOUTHWEST THROUGH THE MORNING AND PUSH THE LINGERING BANDS OFF
SHORE. IN ADDITION...SUBSIDENCE ASSOCIATED WITH THE HIGH WILL BE
LOWERING THE INVERSION HEIGHTS BELOW 4KFT BY 18Z AND ALSO HELP TO
BRING AN END TO THE SNOW IN THE U.P. ATTENTION THEN TURNS TO
SHORTWAVE RUNNING ALONG THE US/CANADIAN BORDER ON WEDNESDAY
AFTERNOON AND THE ASSOCIATED WEAK SURFACE LOW OR TROUGH THAT
FOLLOWS A SIMILAR PATH. THE FARTHER NORTH IDEA SEEN YESTERDAY SEEMS
TO BE HOLDING TRUE WITH THE 00Z RUNS TODAY (AND HAS EVEN TRENDED A
LITTLE FARTHER NORTHEAST)...WHICH WILL LIKELY LIMIT PRECIPITATION
CHANCES OVER MUCH OF UPPER MICHIGAN WEDNESDAY AFTERNOON/EVENING.
BEST DEEP MOISTURE WILL BE OVER THE NORTHERN PORTIONS OF LAKE
SUPERIOR WHERE THE SHORTWAVE TRACKS...WHILE DRY AIR IN THE LOWER
LEVELS LINGERING FROM THE DEPARTING SURFACE RIDGE WILL LIKELY LIMIT
PRECIPITATION OVER THE SOUTHERN PORTIONS OF UPPER MICHIGAN. GOING
FORECAST HAD A FAIRLY GOOD HANDLE ON THIS (CHANCES OVER LAKE
SUPERIOR AND THE KEWEENAW) BUT PUSHED THE SLIGHTS FARTHER NORTH
AND CLOSER TO LAKE SUPERIOR.
UNCERTAINTY GROWS FOR LATER WEDNESDAY NIGHT INTO THURSDAY...AS
MODELS ARE CONTINUING TO STRUGGLE WITH THE SURFACE TROUGH AND
EASTWARD EXTENT OF THE SURFACE RIDGE STRETCHING INTO ONTARIO. THE
SURFACE TROUGH WILL LIKELY SHIFT SOUTHEAST OF THE CWA SOMETIME LATE
WEDNESDAY NIGHT INTO THURSDAY...WHICH WILL GRADUALLY SHIFT WINDS TO
MORE OF A NORTHERLY OR NORTH-NORTHEAST DIRECTION. THE TIMING OF
THIS TRANSITION WILL DETERMINE PRECIPITATION TIMING AS COLDER AIR
(900-850MB TEMPS FALLING TO -13C) MOVES SOUTH OVER THE NW HALF OF
THE CWA. THIS COLDER AIR IS VERY SHALLOW (INVERSION HEIGHTS AT 850MB
OR 3-5KFT) SO SNOW SHOWER STRENGTH SHOULD BE LIMITED. THUS...WILL
CONTINUE LOW CHANCE POPS OVER THE NORTHWEST HALF OF THE CWA FOR
THURSDAY MORNING AND THEN SPREAD IT INTO NORTH CENTRAL AND PARTS OF
NORTHEAST UPPER MICHIGAN IN THE AFTERNOON.
THURSDAY NIGHT/S WEATHER IS DEPENDENT ON A LOW DEVELOPING ON THE
TROUGH IN THE MID MISSISSIPPI VALLEY AND THEN TRACKING NORTHEAST
THROUGH LOWER MICHIGAN ON THURSDAY NIGHT. MODELS STILL DIFFERING ON
THE EXACT TRACK OF THE LOW...BUT 00Z MODEL DETERMINISTIC RUNS
AND ENSEMBLE MEMBERS SEEM TO BE CENTERING ON CENTRAL TO SOUTHERN
LOWER MICHIGAN (PROBABLY TRACKING THROUGH OR SOUTH OF SAGINAW BAY
AFTER MIDNIGHT THURSDAY NIGHT). WHILE THE LOW ISN/T IN THE MOST
FAVORABLE POSITION OF THE RIGHT REAR OF THE UPPER JET AND NORTHERN
STREAM SHORTWAVE...THE UPPER GREAT LAKES IS. THUS...EXPECT THE
PRECIPITATION TO BE FARTHER NORTHWEST FROM THE LOW AND
INFLUENCING A GOOD PORTION OF THE CWA. ONE LARGER SCALE ITEM TO KEEP
AN EYE ON IS THE ECMWF/S INSISTENCE ON A THIN STREAK OF ENHANCED MID
LEVEL FGEN SLIDING ACROSS UPPER MICHIGAN. SINCE THE LOW LEVEL FLOW
WILL BE OUT OF THE NORTHERLY DIRECTION AND TEMPERATURES WILL BE COLD
ENOUGH FOR LAKE ENHANCEMENT (850MB TEMPS AROUND -13C) OVER THE
NORTHERN PART OF THE U.P. WILL CONTINUE TO SHOW HIGH CHANCE AND LOW
LIKELY POPS ACROSS THE AREA...WITH THE HIGHEST VALUES IN THE NORTH
WIND FAVORED LOCATIONS. CONFIDENCE IS A LITTLE LOWER ON WIDESPREAD
ADVISORY SNOWFALL AND MOST AREAS WILL PROBABLY ONLY SEE 2-3IN OF
SNOW...ALTHOUGH LAKE ENHANCED AREAS MIGHT REACH THE 3-4IN ADVISORY
VALUES. ON THE BACK SIDE OF THE LOW...MODELS CONTINUE TO SHOW
SIGNIFICANT DRYING AND A QUICK END TO ANY LAKE ENHANCEMENT. OPTED
TO SHOW A FASTER DIMINISHING TREND THROUGH THE DAY FRIDAY IN THE
LAKE ENHANCED AREAS AS HIGH PRESSURE QUICKLY BUILDS IN.
THIS HIGH WILL BE SHORT LIVED AS A WEAK SHORTWAVE SLIDES ACROSS THE
UPPER GREAT LAKES LATE FRIDAY NIGHT AND INTO SATURDAY. HAVE TRENDED
POPS UP SLIGHTLY AND THEY MAY NEED TO BE ADJUSTED UP FURTHER IF
MODELS CONTINUE TO INDICATE A QUICK DUSTING OF SNOW.
FOR THE REST OF THE WEEKEND...AREA WILL REMAIN ON THE EASTERN
SIDE OF A BROAD UPPER TROUGH OVER THE CENTRAL CONUS...WITH A
BULK OF THE ENERGY AROUND NEW MEXICO AND TEXAS. THE DISTURBANCE NEAR
TEXAS WILL SHIFT NORTHEAST ON SUNDAY WHILE A NORTHERN STREAM WAVE
DROPS SOUTHEAST TOWARDS THE UPPER GREAT LAKES. THE MAIN LOW
ASSOCIATED WITH THIS ENERGY WILL MOVE THROUGH OR JUST NORTH OF THE
OHIO RIVER VALLEY WHILE HIGH PRESSURE IN SASKATCHEWAN ON SATURDAY
WILL MOVE SOUTHEAST ON SUNDAY AND OVER THE UPPER GREAT LAKES REGION
FOR MONDAY. WITH THE TRACK OF THE LOW ON SUNDAY...WOULD EXPECT THE
PRECIPITATION TO STAY JUST SOUTHEAST OF THE CWA...BUT THE WINDS WILL
TURN TO A NORTHERLY DIRECTION AND BRING COLDER AIR INTO THE AREA
SATURDAY NIGHT THROUGH MONDAY. THIS WILL BRING INCREASING CHANCES OF
LAKE EFFECT SNOW FOR SATURDAY NIGHT THROUGH SUNDAY. STILL SOME
DIFFERENCES IN LOW LEVEL WINDS IN THE GFS/ECMWF...BUT A GENERAL
NORTH TO NORTHWEST WIND LAKE EFFECT SEEMS LIKELY (850MB TEMPS
FALLING TO -23C). ONE CONCERN IS FOR THE DECENT SUBSIDENCE ON THE
BACK SIDE OF THE LOW AIDED BY THE APPROACHING HIGH. MODEL SOUNDINGS
SHOW THAT SUBSIDENCE LIMITING INVERSION HEIGHTS TO 5-6KFT AND WOULD
PUT A CRIMP ON STRONGER LAKE EFFECT SNOW SHOWERS. LIKE THE IDEA OF
THE PREVIOUS SHIFT OF HIGH CHANCE AND LOW LIKELY POPS FOR THE
NORTHERLY AREAS ON SUNDAY AND THEN SHIFTED TOWARDS NORTHWEST SUNDAY
NIGHT. BACKING WINDS AND INCREASING SUBSIDENCE ASSOCIATED WITH THE
HIGH ON MONDAY WILL LEAD TO LOWER POPS AND A TREND TOWARDS WESTERLY
WIND AREAS.
WITH THAT COLD AIR...EXPECT HIGHS TO BE SIMILAR TO WHAT WE HAVE
SEEN RECENTLY AND HAVE TRENDED HIGHS DOWN INTO THE TEENS FOR SUNDAY
(TEMPS FALLING IN THE AFTERNOON) AND KEPT THAT SAME IDEA FOR MONDAY.
SHOULD BE A CHILLY NIGHT FOR AREAS AWAY FROM THE LAKE EFFECT ON
SUNDAY NIGHT AND HAVE TRENDED LOWS DOWN INTO THE SINGLE DIGITS BELOW
ZERO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1225 PM EST TUE DEC 17 2013
AS A COLD FNT/AREA OF DEEPER MSTR SURGE ACROSS UPR MI THIS AFTN/
EVNG...EXPECT A PERIOD OF IFR CONDITIONS TO IMPACT IWD AND
ESPECIALLY CMX...WHERE SHARPER UPSLOPE WIND COMPONENT/GREAT EXPOSURE
TO FCST WNW WIND WL ENHANCE THE SHSN/BLSN AND POTENTIAL FOR LOWER
CIGS. SAW MAY SEE MVFR CONDITIONS WITH A DOWNSLOPE WIND COMPONENT
LIMITING THE POTENTIAL FOR LOWER CONDITIONS. THE APRCH OF A HI PRES
RDG AXIS/DRIER AIR LATER TNGT WL CAUSE IMPROVING WX...WITH
CONDITIONS IMPROVING TO VFR LATER TNGT W-E FOLLOWING THE PASSAGE OF
RDG AXIS WSHFT TO THE SW. A MORE PERSISTENT UPSLOPE WIND COMPONENT
WL SLOW THE IMPROVEMENT AT CMX.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 343 PM EST TUE DEC 17 2013
EXPECT NW WINDS TO 25-30 KTS THIS EVENING BEHIND A COLD FRONTAL
PASSAGE TO DIMINISH AND BACK TO THE SW WITH APPROACH OF A HI PRES
RIDGE LATER TONIGHT INTO WED. A VERY CHANGEABLE WEATHER PATTERN WILL
THEN DOMINATE THE UPPER GREAT LAKES THE REST OF THE WEEK...WITH HARD
TO TIME DISTURBANCES IMPACTING LAKE SUPERIOR. CONFIDENCE IS LOW IN
TIMING THESE DISTURBANCES AND ACCOMPANYING WIND SHIFTS...BUT GALES
APPEAR UNLIKELY THRU THE FORECAST PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS GAYLORD MI
108 PM EST TUE DEC 17 2013
.SYNOPSIS...
ISSUED AT 433 AM EST TUE DEC 17 2013
LIGHT ACCUMULATIONS ARE EXPECTED OVER NORTHWEST LOWER AND NORTHERN
CHIPPEWA COUNTY...WHERE LAKE EFFECT SNOW WILL CONTINUE THROUGH THE
DAY AND THEN INTENSIFY LATE THIS EVENING PROVIDING POSSIBLY LOCALLY
MODERATE SNOWFALL ACCUMULATIONS. CONTINUED BOUTS OF OCCASIONAL SNOW
ARE EXPECTED OVER THE NEXT COUPLE OF DAYS...AS MULTIPLE SYSTEMS PASS
THROUGH THE AREA. AFTER TODAY...WE WILL SEE SOMEWHAT MILDER
TEMPERATURES IN THE REGION.
&&
.UPDATE...
ISSUED AT 1251 PM EST TUE DEC 17 2013
THE SNOW BAND IN THE M-55 CORRIDOR WILL CONTINUE EAST, AND IT
SEEMS WILL DIMINISH OVER THE NEXT COUPLE OF HOURS. OTHERWISE,
WATCHING TO SEE IF THE LES WILL BEGIN TO FORM. THE LAST TROUGH HAS
TO GET ACROSS N LAKE MICHIGAN, BEFORE THAT HAPPENS. 850 MB
TEMPERATURES ARE GOOD, AS WELL AS THE 850-700 MB MOISTURE (RH>70%)
SO WILL BE ADJUSTING THE FORECAST AS THE LES BEGINS.
UPDATE ISSUED AT 1015 AM EST TUE DEC 17 2013
BAND OF SNOW IS MOVING SOUTH OF M-72 AND ALONG THE M-55 CORRIDOR.
SNOW HAS STRUGGLED TO GET MUCH NORTH OF THIS AREA. ONCE THE
INITIAL BAND IS THROUGH, THE SNOW SHOWERS BECOME SCATTERED, WITH
THE BACK EDGE ALONG A SECONDARY TROUGH (15Z RUC ANALYSIS). SO WILL
TWEAK THE POP GRIDS A BIT TO ACCOUNT FOR THE SNOW TRACK AND THE
BACK END OF THIS SYSTEM. THIS WOULD SEEMINGLY LEAVE MOST IF NOT
ALL OF THE M-32 CORRIDOR AND NORTH OUT OF THE SNOW THIS MORNING,
AND PROBABLY PART OF THE EARLY AFTERNOON. THERE IS VERY LITTLE
GOING ON IN LAKE SUPERIOR SO WILL KEEP THE CHANCE POPS FOR THE
TIME BEING.
UPDATE ISSUED AT 649 AM EST TUE DEC 17 2013
BACK EDGE OF SYSTEM SNOWS EXITING NE LOWER BEHIND DEPARTING
SHORTWAVE. SUBSIDENCE AND DRYING FROM ALOFT IN ITS WAKE WITH SOME
REAL LOW CLOUDS SWEPT IN OVER MOST OF THE AREA. NEXT SHORTWAVE
ALREADY ABOUT TO EXERT ITSELF ON THE GTV BAY REGION
SOUTHWARD....WITH LIGHT SNOWS MOVING IN OVER THE NEXT FEW HOURS.
THERE IS ALSO A NARROW CORRIDOR OF MODERATE SNOWS SET TO AFFECT
AREAS CLOSER TO THE FRANKFORT...MANISTEE AND CADILLAC AREAS.
INCREASED CHANCES FOR SEEING SNOW THERE...AND ALSO BUMPED UP SNOW
AMOUNTS TO UP TO 2 INCHES. NOT OUT OF THE QUESTION TO SEE LOCALLY
HIGHER AMOUNTS AS THE CORRIDOR OF MODERATE SNOWS MAY TRAIN FOR A
COUPLE OF HOURS. THIS IS WORTH KEEPING A CLOSE EYE ON FOR A
POSSIBLE SNEAKIER HIGHER SNOWFALL.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 433 AM EST TUE DEC 17 2013
IT SIMPLY DOESN`T STOP...AND THAT`S A GOOD THING FOR THE SNOW FAN
THAT I AM! BUT...LAKE PROCESSES THAT ARE ON PERPETUAL OVERDRIVE SURE
MAKES FOR SOME CHALLENGING FORECAST SHIFTS. THIS ONE IS NO DIFFERENT
(WHY WOULD IT BE?)...WITH A FULL-FLEDGED SOUTHWEST FLOW EVENT
IMPACTING EASTERN UPPER AS IF THIS TYPING...NO DOUBT HELPED ALONG BY
PASSING SHORTWAVE TROUGH/ALBERTA CLIPPER TYPE SYSTEM. SYSTEM ITSELF
HAS A TOUCH OF SNOW WITH IT...BRINGING SOME LIGHT ACCUMULATIONS TO
MOST. PATTERN REMAINS IN RAPID-FIRE MODE...WITH NEXT SHORTWAVE AND
POCKET OF UPWARD QG SUPPORT ALREADY RACING EAST INTO WESTERN
WISCONSIN. PLETHORA OF FORECAST CHALLENGES GIVEN THIS ENERGETIC...
LAKE ENHANCED RICH PATTERN...WITH MAIN EMPHASIS CENTERED ONCE AGAIN
ON ADDITIONAL SNOW AMOUNTS AND ASSOCIATED HEADLINE CONCERNS.
OVERHEAD WAVE LOOKS TO EXIT QUICKLY EARLY THIS MORNING...WITH
SUBSIDENCE AND MID LEVEL DRYING KICKING IN BEHIND IT. WIDESPREAD
SNOWS WILL FOLLOW SUITE...ENDING FROM WEST TO EAST WITHIN THE NEXT
FEW HOURS. MAIN CONCERN REMAINS IMPRESSIVE...BUT INCREASING TRANSIENT
...SOUTHWEST FLOW BAND EXTENDING FROM LEELANAU COUNTY UP
INTO THE STRAITS. WINDS ALREADY VEERING CONSIDERABLY OVER THE
WESTERN HALF OF THE BIG POND...AND SIMPLE EXTRAPOLATION WOULD
SUGGEST THIS WIND SHIFT LINE PROPELLING THE BAND INLAND QUICKLY
SHORTLY AFTER ISSUANCE OF THIS FORECAST PACKAGE. NO DOUBT A BURST OF
VERY HEAVY SNOW WILL ACCOMPANY THIS BAND...LIKELY IN EXCESS OF ONE
INCH PER HOUR. HOWEVER...THIS LOOKS TO BE A SHORT-LIVED EVENT FROM
THIS POINT ON...AND WILL SIMPLY CANCEL ALL INHERITED ADVISORIES.
NEXT LOW AMPLITUDE WAVE APPROACHES QUICKLY THIS MORNING...WITH MAIN
CORE OF DYNAMICS SPREADING BY TO OUR SOUTH. BEST CHANCE FOR
ATTENDANT LIGHT SNOW EXPECTED ACROSS THE SOUTH THIRD OF THE AREA.
LAKE SUPPORT BY THIS TIME LOOK NEGLIGIBLE AS H8 TEMPERATURES "WARM"
TO AROUND -8C BY SUNRISE. THUS...NOT EXPECTING A WHOLE LOT OF
ADDITIONAL ACCUMULATION TODAY...LIKELY JUST AROUND AN INCH OR SO
FROM CADILLAC AND POINTS WEST. MORE SCATTERED AND LIGHTER SNOW
SHOWERS EXPECTED ELSEWHERE TODAY WITH MINIMAL ACCUMULATIONS. MIGHT
ACTUALLY FEEL KINDA BALMY AS HIGHS REACH INTO THE MIDDLE...AND
PERHAPS...UPPER 20S.
LAKE CONCERNS RAMP UP ONCE AGAIN TONIGHT AS WINDS SWING AROUND
WEST/NORTHWESTERLY AND NEXT SLUG OF COLDER AIR DROPS INTO THE
NORTHERN LAKES. HOWEVER...UNLIKE RECENT ARCTIC PLUNGES...THIS ONE IS
NOT QUITE AS COLD...WITH H8 TEMPERATURES ONLY FALLING INTO THE
NEGATIVE MID TEENS BY MORNING. BACKGROUND SYNOPTIC MOISTURE NOT TOO
SHABBY AT ALL...WITH GOOD MOISTURE THROUGH RESPECTABLE 750MB CBL
HEIGHT. WHILE STRONGEST OMEGA IS PEGGED JUST SHORT OF THE DGZ...AT
LEAST SOME LIFT IS NOTED IN THE BOTTOM END OF THIS ZONE. LACK OF
WELL-DEFINED LOW LEVEL CONVERGENCE AXES AND SOMEWHAT MORE MARGINAL
PARAMETERS LISTED ABOVE SHOULD KEEP THIS FROM BECOMING TOO BIG OF AN
EVENT. HAVE TENTATIVELY PAINTED IN 2 TO 4 INCHES IN THE TRADITIONAL
LAKE SNOW BELTS OF BOTH PENINSULAS BY MORNING. DEFINITELY NOT OUT OF
THE REALM OF POSSIBILITY FOR LOCALLY HIGHER AMOUNTS AND HEADLINES.
WILL PUNT THIS DECISION TO THE DAY CREW...LEAVING TIME TO MORE
THOROUGHLY ACCESS INCOMING AIRMASS VIA 12Z RAOBS. LOWS TONIGHT BACK
DOWN INTO THE TEENS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 433 AM EST TUE DEC 17 2013
NRN MICHIGAN WILL BE UNDERWAY INTO A LESS COLD PATTERN WITH
TEMPERATURES RETURNING TO MORE NEAR NORMAL LEVELS...AS DEEPER UPPER
TROUGHING IS REPLACED BY A FASTER MORE ZONAL FLOW ALOFT. UPSTREAM
TROUGHING WILL HOWEVER SEND SOME ENERGY INTO THE GREAT LAKES
WEDNESDAY...BEFORE CUTTING OFF ACROSS THE WESTERN CONUS. GETS A TAD
MORE ACTIVE THURSDAY NIGHT AND OVER THE WEEKEND WITH CUTOFF LOW
DIGGING INTO THE FAR SRN ROCKIES...AND OVERALL UPPER AIR PATTERN
BECOMING MORE AMPLIFIED BY THE COMING WEEKEND. THERE IS AN EXPECTED
TAP OF DEEPER GULF MOISTURE WITH TIME...WITH BOTH JETS USHERING IN
SHORTWAVE ENERGY...NOT PHASING PER SE...BUT CERTAINLY THE CHANCE FOR
A SIGNIFICANT STORM SYSTEM IN THE EASTERN PART OF THE COUNTRY...WITH
AN ASSOCIATED CORRIDOR OF HEAVIER SNOW SOMEWHERE ACROSS OUR NECK OF
THE WOODS.
WEDNESDAY THROUGH THURSDAY...A RELATIVELY QUIET PERIOD OF WEATHER
WITH THE COLD UPPER TROUGH EXITING EAST AND FLOW GOING RATHER ZONAL.
A KINK/SHORTWAVE IN THE WNW FLOW ALOFT OVER ONTARIO WILL DAMPEN AS
IT CROSSES TO OUR NORTH...INDUCING A WEAK SFC LOW/CLIPPER. THIS
CLIPPER WILL BE LOSING STRENGTH AS IT LIFTS A WARM FRONT AND BAND OF
DEEPER MOISTURE THROUGH NRN MICHIGAN WEDNESDAY AND WEDNESDAY
EVENING. LIKELY SOME SCATTERED LIGHT LAKE EFFECT SNOW SHOWERS IN
WESTERLY FLOW REGIMES...AT LEAST IN THE MORNING WITH MINIMAL
ACCUMULATIONS UNDER AN INCH. LOW LEVEL FLOW AHEAD OF THE CLIPPER
WILL BRING WARMER LOW LEVEL TEMPERATURES TO EVENTUALLY SHUT OFF ANY
LES. SNOW CHANCES FROM THE SYSTEM ITSELF IS RATHER MINIMAL AS WELL
WITH AN INITIAL DRY LAYER H8-H7 LAYER GETTING SATURATED BRIEFLY
ALONG WITH THE UPPER LEVELS FOR A WINDOW OF OPPORTUNITY FOR A NARROW
CORRIDOR OF LIGHT SNOW TO PUSH ON THROUGH. WILL JUST HAVE SOME
SMALLISH CHANCES FOR NOW. A FAIRLY WEAK COLD FRONT DROPS IN OVER US
WEDNESDAY NIGHT INTO THURSDAY...BEFORE LAYING OUT ACROSS LOWER
MICHIGAN. WITH AN INCREASING LIGHT AND MORE VARIABLE FLOW DEVELOPING
AND SHALLOW SUB H8 MOISTURE IN THE MIX...A GOOD BET FOR SOME STRATUS
ISSUES. ACROSS THE EASTERN UP...MAYBE SOME LIGHT SNOW/FLURRIES IN
COLDEST AIR OFF LAKE SUPERIOR...BUT IT`S FAIRLY DRY. EXACT PLACEMENT
OF THE FRONT AND STRATUS HAS SOME UNCERTAINTY...BUT STILL NOT MUCH
EXPECTED FROM A SENSIBLE WEATHER STANDPOINT. WILL SEE SOME INCREASED
CLOUDS DEVELOPING LATER THURSDAY...AS INITIAL SRN STREAM ENERGY AND
NEXT NRN STREAM WEAK WAVE DROP IN TOWARD THE WESTERN GREAT LAKES.
THURSDAY NIGHT THROUGH SATURDAY...THAT FRONT WILL NOT BE
FORGOTTEN...AND IT`S PLACEMENT WILL BE IMPORTANT FOR THE THURSDAY
NIGHT AND EARLY FRIDAY TIME PERIOD. THE AFOREMENTIONED ENERGY FROM
BOTH STREAMS ARRIVE...AND TRY TO WORK WITH GULF MOISTURE TRYING TO
LIFT INTO THE LOWER AND MIDDLE MISSISSIPPI VALLEY. CLOUDS AND
PRECIPITATION ARE EXPECTED TO DEVELOP WITH DEEP MOISTURE SATURATING
THE COLUMN AS WEAK LOW PRESSURE DEVELOPS AND LIFTS NORTHEAST ALONG
THE LAID OUT FRONT. THERMAL PROFILES LOOK TO BE FOR AN ALL SNOW TYPE
EVENT FOR US...WITH AN OUTSIDE CHANCE THAT WE COULD SEE SOME RAIN
MIX IN ALONG THE M-55 CORRIDOR. THIS ALSO WHERE THE BEST CHANCES FOR
PRECIPITATION WILL RESIDE...BUT NRN STREAM WAVE WILL STILL PRESENT
ALL OF NRN MICHIGAN WITH A LIKELY SHOT OF LIGHT SNOW THROUGH FRIDAY
MORNING. AGAIN...WHERE THE FRONT WAS...AND WHETHER OR NOT IT SHIFTS
SOUTH...ARE KEY IN WHETHER OR NOT WE CAN GET SOME COLD ENOUGH AIR IN
HERE FOR SOME LIGHT LES SNOW SHOWERS...AND THERE IS QUITE A BIT OF
UNCERTAINTY THERE. EITHER WAY...EVEN WITH ANOTHER WEAK NRN STREAM
WAVE FRIDAY NIGHT INTO SATURDAY...ANY PRECIPITATION WE GET LOOKS TO
BE MINIMAL. ALL CONSIDERED...WILL NOT BE SURPRISED AT ALL...IF THERE
ISN`T SOME SORT OF LIGHT SNOW FLOATING AROUND.
SATURDAY NIGHT THROUGH MONDAY...POTENTIAL STORM? SRN STREAM CUTOFF
EXPECTED TO GET LIFTED INTO THE UPPER TROUGH...BUT NOT TOTALLY PHASE
TOGETHER. HOWEVER...A DEEP GULF OF MOISTURE TAP LIFTS NORTHWARD
AHEAD OF THE SRN STREAM WAVE...AND GET FORCED ALONG THE SFC FRONT
WHICH IS EXPECTED ALONG AND NORTH OF THE OHIO RIVER VALLEY....MAYBE
AS FAR NORTH AS SE LOWER MICHIGAN. A TIGHT BAROCLINIC ZONE DEVELOPS
AS LOW PRESSURE LIFTS TOWARD THE EASTERN GREAT LAKES. A CORRIDOR OF
HEAVY PRECIPITATION IS POSSIBLE ALONG THE FRONT...WITH THE NRN FRINGE
INTO COLD ENOUGH AIR FOR WHAT COULD WIND UP BEING AN AXIS OF HEAVIER
SNOWFALL FOR SOMEWHERE IN LOWER MICHIGAN. RIGHT NOW...MAYBE OUR FAR
SE COUNTIES SEEING SOME OF THIS ACTION??? REMAINS TO BE SEEN...AS
TIME DRAWS NEARER. NOT ENOUGH CONFIDENCE JUST YET FOR ANY MENTION
IN THE OUTLOOK SECTION OF THE HWOAPX.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1251 PM EST TUE DEC 17 2013
MVFR TO IFR CIGS ARE CONSTANT OVER THE REGION, AND WILL REMAIN AS
MUCH AS THE SECOND TROUGH MOVES THROUGH THE FORECAST AREA, AND
LAKE EFFECT SNOW BEGINS ALONG LAKE MICHIGAN. AT THIS POINT IT
LOOKS LIKE PLN AND TVC WILL BE MOST AFFECTED FROM THE WNW WIND
DIRECTION. MBL WILL GET SOME LAKE EFFECT, BUT PROBABLY NOT TO THE
EXTENT AS THE OTHER TWO. APN WILL BE ONLY GET SNOW AND VSBY
ISSUES, IF A SNOW BAND ELONGATES AND PASSES THROUGH THE SITE.
&&
.MARINE...
ISSUED AT 433 AM EST TUE DEC 17 2013
WEST/SOUTHWEST WINDS WILL SLOWLY VEER MORE WESTERLY...AND
EVENTUALLY NORTHWESTERLY TODAY INTO THIS EVENING. STRONGEST CORE
OF WINDS EXPECTED ACROSS NORTHERN LAKE MICHIGAN...WHERE SCA
CONDITIONS WILL CONTINUE RIGHT THROUGH TONIGHT. WINDS WILL QUICKLY
BACK SOUTHWESTERLY ONCE AGAIN WEDNESDAY WELL AHEAD OF NEXT
DEVELOPING LOW PRESSURE SYSTEM.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST WEDNESDAY FOR LMZ344>346.
LS...NONE.
&&
$$
UPDATE...JL
SYNOPSIS...TL
SHORT TERM...MB
LONG TERM...SD
AVIATION...JL
MARINE...MB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1144 AM CST TUE DEC 17 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST TUE DEC 17 2013
THE THERMAL RIDGE WEAKENED A BIT WITH THE PASSAGE OF A WEAK COLD
FRONT TONIGHT. AS A RESULT...HIGH PRESSURE IS BUILDING THROUGH THE
NRN AND CNTL HIGH PLAINS ALLOWING FOR RADIATIONAL COOLING IN MOST
VALLEYS. THE RUC SHOWS LOW PRESSURE REFORMING ACROSS THE HIGH
PLAINS TODAY AND THIS SHOULD LIFT A WARM FRONT PART WAY THROUGH
THE FCST AREA. THE WARM FRONT WOULD LIKELY REACH HIGHWAY 183 BY
LATE AFTN.
FCST HIGHS FOLLOW THE WARMEST MODEL...THE HRRR FOR HIGHS NEAR 60
ACROSS THE SOUTHWEST WHERE THE THERMAL RIDGE WILL BE IN PLACE ALL
DAY. JUST SCATTERED HIGH CLOUDS ARE EXPECTED AS A SOLID BANK OF
CIRRUS IS OVER BRITISH COLUMBIA THIS AM.
THE RAP MODEL SHOWS WEST WINDS AT H850MB AT 15 TO 30KT AND THE MODEL
CONSENSUS 500M AGL WINDS ARE WEST AND SOUTHWEST AT 10 TO 20KT WHICH
WOULD PRODUCE 10 TO 20 MPH WINDS AT THE SFC.
LOWS TONIGHT VARY WIDELY WITH TEENS IN VALLEYS TO NEAR 30 ACROSS THE
SANDHILLS. A SHALLOW INVERSION SHOULD FORM GIVEN THE LIMITED HIGH
CLOUD COVER EXPECTED AND WESTERLY H850MB WINDS OF 20 TO 40KT. H850MB
TEMPS RISE IN THE TEENS ACROSS WRN NEB.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 355 AM CST TUE DEC 17 2013
PRIMARY CONCERNS FOR THIS FORECAST PERIOD ARE TEMPERATURES FOR
WEDNESDAY AND THURSDAY...AS WELL AS PRECIPITATION CHANCES AND
TYPES FOR THURSDAY AND THURSDAY NIGHT.
THE SHORTWAVE TROUGH CURRENTLY OVER THE GULF OF ALASKA WILL SPLIT
WEDNESDAY AND WEDNESDAY NIGHT WHICH WILL IMPACT THE LOCAL AREA IN
DIFFERENT WAYS. ONE PART OF THIS ENERGY WILL DIG SOUTH ALONG THE
WEST COAST WHICH WILL HELP THE THERMAL RIDGE BUILD OVER THE PLAINS.
THE SECOND PIECE OF ENERGY WILL STAY IN THE NORTHERN STREAM WHICH
WILL MOVE ACROSS THE PLAINS AS A WEAK SHORTWAVE TROUGH THURSDAY AND
THURSDAY NIGHT...WHICH WILL PUSH AN ARCTIC COLD FRONT ACROSS THE
FORECAST AREA.
STARTING ON WEDNESDAY...IS STILL A QUESTION TO HOW WARM IT WILL GET.
AS MENTIONED ABOVE THE THERMAL RIDGE BUILDS IN WITH ANOMALOUSLY WARM
AIR SEEN ALOFT. AT 18Z WEDNESDAY MODELS INDICATE 850MB TEMPERATURES
WILL HAVE RISEN BETWEEN 11C AND 15C ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA. MODELS ARE ONLY MIXING THE BOUNDARY LAYER TO AROUND 875MB
SO DON/T REALIZE THE POTENTIAL WARMING. WINDS WILL BE FAIRLY LIGHT
WHICH WON/T HELP THE MIXING DEPTH...BUT DON/T THINK THE MODELS ARE
HANDLING THIS MIXING WELL AND IN MOST LOCATIONS WENT ABOVE MOST
GUIDANCE FOR HIGHS. MUCH OF THE NORTHERN TIER OF COUNTIES CONTINUES
TO HAVE SNOW ON THE GROUND WHICH AS OF MONDAY STILL HAD A STRONG
IMPACT ON TEMPERATURES AS HIGHS WERE ONLY IN THE LOW 40S...WITH
UPPER 50S AND LOW 60S OVER THE REST OF THE FORECAST AREA. SHOULD
HAVE CONTINUED MELTING TODAY...SO THE SNOW SHOULDN/T HAVE AS MUCH
IMPACT ON HIGHS...BUT WITH WET GROUND MAY NOT BE ABLE TO MIX TOO
MUCH SO CONTINUED THE TREND OF COOLER TEMPERATURES ACROSS THE NORTH.
THIS MAY NEED TO BE MODIFIED DEPENDING ON WHAT HIGHS DO TODAY.
COLD FRONT WILL PUSH SOUTH THROUGH THE FORECAST AREA WEDNESDAY
NIGHT...WITH THE COLDEST AIR LAGGING BEHIND THE FRONT. THE LOW
LEVELS START TO SATURATE BY 12Z THURSDAY BUT ABUNDANT DRY AIR IN THE
MID LEVELS WILL KEEP FROM THE NEED FOR PRECIPITATION CHANCES
WEDNESDAY NIGHT.
ON THURSDAY...THERE ARE STILL DISCREPANCIES AS TO HOW FAST THE COLD
AIR WILL MOVE IN. FOR EXAMPLE GFS ENSEMBLE MEMBERS VARY FROM 19F TO
42F FOR HIGHS AT KLBF. BECAUSE OF THESE DIFFERENCES STAYED FAIRLY
SIMILAR TO ONGOING FORECAST FOR HIGHS. WITH COLD AIR ADVECTION
THROUGH THE DAY...MAY SEE HIGHS EARLY WITH FALLING OR NEARLY STEADY
TEMPERATURES. IN TERMS OF PRECIPITATION FOR THURSDAY...THERE IS
AGREEMENT BETWEEN MODEL SOLUTIONS OF THE COLUMN BECOMING SATURATED
THURSDAY MORNING OVER THE NORTHERN PANHANDLE...AND WITH THE COLD AIR
ALREADY IN PLACE SHOULD START TO SEE SNOW IN THE MORNING HOURS. AS
THE ENTIRE COLUMN COOLS...WITH SOME LAYERS REACHING THE DENDRITIC
GROWTH ZONE...MIGHT GET SOME HIGHER SNOW TO LIQUID RATIO SNOWS UP
OVER NORTHWEST NEBRASKA. ACTUALLY...BY LATE THURSDAY NIGHT MOST OF
THE SOUNDING IS ISOTHERMAL IN THE DENDRITIC GROWTH ZONE.
HOWEVER...AT THIS POINT THE UPPER LEVEL SYSTEM IS WELL PAST AND THE
AREA IS IN AN AREA OF SUBSIDENCE AND LIFT IS MINIMAL SO THERE IS
ENOUGH DISCONNECT BETWEEN THE FAVORABLE CONDITIONS TO LIMIT FROM
HEAVY SNOWS. COULD SEE A COUPLE INCHES...POSSIBLY UP TO 4 ON THE
PINE RIDGE. WILL PROBABLY SEE SOME LIGHT SNOW ACROSS THE REST OF
NORTHERN NEBRASKA...BUT ONSET WILL BE LATER IN THE DAY THURSDAY AND
WITH THE UPWARD FORCING MOSTLY GONE BY MIDNIGHT EXPECT JUST LIGHT
AMOUNTS. DIFFERENT CONCERN IS FREEZING DRIZZLE FOR CENTRAL CHERRY
COUNTY AND EASTWARD ON THURSDAY. THE LOWEST 2500FT BECOME SATURATED
BY 18Z THURSDAY ACCORDING TO SOUNDINGS AT KVTN...WHILE A DEEP DRY
MID LAYER MAY PROHIBIT SEEDER FEEDER MECHANISM FROM OCCURRING FOR A
FEW HOURS. THERE IS DECENT OMEGA IN THESE LOW LEVELS SO DID ADD
CHANCES FOR FREEZING DRIZZLE INTO THE FORECAST FOR THURSDAY.
WILL ALSO BE QUITE WINDY ON THURSDAY AND THURSDAY NIGHT BEHIND THE
COLD FRONT WHICH WILL DROP WIND CHILLS TO AROUND -10F BY FRIDAY
MORNING.
LOOKING INTO THE WEEKEND...THE UPPER LOW OVER THE SOUTHWEST WILL
MIGRATE ACROSS THE SOUTHERN PLAINS WHILE THE LOCAL AREA WILL SEE
ANOTHER SHORTWAVE TROUGH MOVE ACROSS THE AREA THROUGH THE NORTHERN
STREAM. THERE IS SOME DIFFERENCES ON TIMING OF THIS NEXT
SYSTEM...BUT SHOULD BE MOVING THROUGH SOMETIME SATURDAY NIGHT/SUNDAY.
DOESN/T LOOK LIKE MUCH FOR PRECIPITATION WITH THIS NEXT SYSTEM BUT
THERE IS POTENTIAL FOR ANOTHER PUSH OF ARCTIC AIR INTO THE AREA
BEHIND IT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1141 AM CST TUE DEC 17 2013
VFR CONDITIONS THE NEXT 24 HOURS. NORTHWEST UPPER LEVEL FLOW WILL
FLATTEN SOME AS RIDGE MIGRATES EAST. PACIFIC MOISTURE WILL STREAM
ACROSS THE ROCKIES WITH FEW/SCT HIGH CLOUDS AT TIMES ACROSS THE
AREA. WINDS WILL BE VARIABLE AND LESS THAN 10 KTS...ALTHOUGH
PREVAILING WIND DIRECTION WILL BE WESTERLY TO SOUTHWESTERLY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...MASEK