Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/06/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
256 PM MST WED DEC 4 2013
.SYNOPSIS...A STRONG STORM SYSTEM MOVING THROUGH THE WESTERN
UNITED STATES WILL BRING A CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW
TO SOUTHEAST ARIZONA THROUGH THURSDAY. THIS SYSTEM WILL ALSO BRING
IN MUCH COOLER TEMPERATURES...WITH WIDESPREAD FREEZING TEMPERATURES
ACROSS ALL OF SOUTHEAST ARIZONA FRIDAY MORNING. ANOTHER STORM SYSTEM
WILL BRING GUSTY WINDS...A CHANCE OF THE PRECIPITATION AND A
REINFORCEMENT OF COLDER AIR LATE THIS WEEKEND.
&&
.DISCUSSION...THE UPPER PATTERN IS DEFINED BY A HIGH AMPLITUDE UPPER
RIDGE IN THE EASTERN PACIFIC...AND A LONGWAVE TROUGH ACROSS THE
WESTERN STATES. SHORTWAVE ENERGY MOVING SOUTH ALONG THE CALIFORNIA
COAST WILL ROTATE INTO THE SOUTHERN EDGE OF THIS TROUGH BEFORE IT
TRACKS ACROSS THE AREA TONIGHT AND THURSDAY. THE TIGHT GRADIENT OUT
AHEAD OF THIS TROUGH HAS RESULTED IN BREEZY TO WINDY CONDITIONS...
ESPECIALLY TO THE EAST AND SOUTH OF TUCSON. SURFACE OBSERVATIONS IN
KDUG INDICATE SUSTAINED WINDS IN THE 25 TO 30 MPH RANGE WITH GUSTS
TO 45 MPH. A WIND ADVISORY IS IN EFFECT TO THE EAST UNTIL 8 PM MST
THIS EVENING. THE LATEST MODEL GUIDANCE STILL INDICATES 45 KT FLOW
ACROSS COCHISE AT 06Z TONIGHT. THIS USUALLY MEANS THAT LOCALIZED
AREAS NEAR THE HUACHUCA MOUNTAINS WILL CONTINUE TO EXPERIENCE STRONG
AND GUSTY WINDS WELL INTO THE OVERNIGHT HOURS.
ACCORDING TO THE LATEST SURFACE OBSERVATIONS...THE SOUTHERN TIP OF
THE SURFACE COLD FRONT ASSOCIATED WITH THIS SYSTEM IS CURRENTLY
POSITIONED ACROSS CENTRAL PIMA COUNTY EXTENDING INTO NW PINAL
COUNTY. AT 230 PM MST...KEMX RADAR JUST BEGINNING TO INDICATE SHOWERS
DEVELOPING ACROSS THE TOHONO OODHAM NATION. THE HRRR AND UNIVERSITY
OF ARIZONA WRF MODELS INDICATE THAT THE COLD FRONT WILL PUSH WEST
INTO TUCSON BY 5 PM THIS AFTERNOON WITH PCPN BEGINNING TO EXPAND AND
ENHANCE AS IT MOVES FARTHER EAST. EXPECT SHOWERS TO BECOME MORE
NUMEROUS THIS EVENING WITH THE MAJORITY OF THE PCPN AFFECTING THE
CWA OVERNIGHT INTO THURSDAY MORNING. MOISTURE SOMEWHAT LIMITED WITH
THIS SYSTEM AND STILL EXPECT ONLY A TENTH TO A THIRD INCH WITH MAYBE
A HALF INCH IN THE MOUNTAINS. THIS TRANSLATES INTO SNOWFALL AMOUNTS
JUST BELOW ADVISORY CRITERIA. IT IS POSSIBLE THAT SOME OF THE
HIGHEST PEAKS MAY BARELY HIT LOW END SNOW ADVISORY CRITERIA...BUT IT
WILL NOT BE WIDESPREAD ENOUGH TO WARRANT AN ADVISORY.
THE MAIN ISSUE WITH THIS SYSTEM IS NOT THE WIND OR THE PCPN...BUT
THE TEMPERATURES. COLD AIRMASS MAKING ITS WAY SOUTH WILL BRING THE
FIRST WIDESPREAD FREEZING TEMPERATURES TO THE LOWER DESERTS FROM
TUCSON WEST. HAVE DECIDED TO ISSUE A FREEZE WARNING FOR FRIDAY
MORNING TO GET THE WORD OUT TO PROTECT PEOPLE...PETS...PIPES AND
PLANTS.
ANOTHER STRONG WEATHER SYSTEM WILL MAKE ITS WAY SOUTH INTO ARIZONA
THIS WEEKEND. THE ECMWF IS MUCH COLDER AND THUS MORE AGGRESSIVE THAN
THE GFS BRINGING PCPN AND ANOMALOUSLY COLDER TEMPS. INCREASED POPS AND
LOWERED TEMPS SAT NIGHT INTO MONDAY TO REFLECT THIS TREND.
&&
.AVIATION...VALID THRU 06/00Z.
UPPER LEVEL JET MOVING ACROSS SOUTHEAST ARIZONA AND INTO NEW MEXICO
BY THURSDAY NOON. ASSOCIATED WITH THIS CHANGE...COLD AIR WILL ADVECT
INTO SOUTHERN ARIZONA TONIGHT AND THURSDAY. STRONG SURFACE WINDS OF
20-25 KT WITH GUSTS UP TO 45 KTS SUBSIDING AROUND 05/06Z. FROM
05/00Z INTO THURSDAY MIDDAY EXPECT ISOLD TO SCT -SHRA. PERIODS OF
MVFR CONDITIONS WILL BE PRESENT IN THE STRONGER SHOWERS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...LOW PRESSURE TROUGH OVER THE WEST IS EXPECTED TO
REMAIN THROUGH THE FIRST PART OF NEXT WEEK. THE STRONG WINDS
ASSOCIATED WITH THIS TROUGH WILL SUBSIDE AROUND MIDNIGHT AND MUCH
COLDER AIR WILL ADVECT INTO THE AREA THURSDAY. TEMPERATURES WILL
DROP ABOUT 15 DEGREES BELOW AVERAGE LATE THURSDAY AND CONTINUE
THROUGH THE WEEKEND. MOISTURE WITH THIS TROUGH IS LIMITED...ALTHOUGH
MANY AREAS WILL SEE LIGHT PRECIPITATION AMOUNTS. A SECOND STORM
SYSTEM WILL DROP INTO THIS TROUGH LATE SATURDAY FOR A CHANCE OF
VALLEY RAIN AND MOUNTAIN SHOWERS...ALONG WITH REINFORCING THE COLDER
TEMPERATURES INTO EARLY NEXT WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 8 PM MST THIS EVENING FOR AZZ507>513.
FREEZE WARNING 10 PM MST THURSDAY NIGHT UNTIL 10 AM MST FRIDAY
MORNING FOR AZZ501>506.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS FLAGSTAFF AZ
915 AM MST WED DEC 04 2013
.SYNOPSIS...A COLD STORM SYSTEM WILL MOVE ACROSS ARIZONA TODAY...
BRINGING RAIN...SNOW...AND GUSTY WINDS. SNOW ACCUMULATIONS ARE
EXPECTED ABOVE 6000 FOOT LEVEL. A VERY COLD AIR MASS WILL SETTLE
ACROSS NORTHERN ARIZONA THROUGH THE REMAINDER OF THE WEEK...WITH HIGH
TEMPERATURES IN THE 20S AND 30S FOR MOST LOCATIONS. ANOTHER STORM
SYSTEM WILL BRING CHANCE OF SNOW TO THE AREA SATURDAY AND SUNDAY.
&&
.DISCUSSION...THE COLD FRONT CONTINUES TO MOVE ACROSS NRN AZ THIS
MORNING. NWS OFFICE NOTED A 7-DEGREE TEMP DROP IN 10 MINUTES AS THE
FRONT MOVED THRU AROUND 8 AM...AND LIGHT RAIN/SNOW SHOWERS RAPIDLY
INCREASED TO MODERATE AND STEADY SNOW WITH THE FRONTAL PASSAGE.
FARTHER NORTHWEST...SNOW WAS DIMINISHING IN COVERAGE AND INTENSITY.
WILL ALLOW ADVISORY OVER NWRN ZONES TO EXPIRE LATER THIS MORNING ON
SCHEDULE. WINTER WEATHER ADVISORY OVER THE MOGOLLON RIM THROUGH THIS
AFTERNOON REMAINS ON TRACK.
CURRENT HRRR PCPN FCST SHOWS THE FRONTAL BAND WILL CONTINUE TO BECOME
NARROWER THRU THE REMAINDER OF THE DAY SUCH THAT LOCATIONS FARTHER TO
THE EAST WILL SEE LESS PCPN OWING TO A SHORTER DURATION THAN AREAS TO
THE WEST. IN ADDITION...SATELLITE IR IMAGERY SHOWS THE COLDEST CLOUD
TOPS ARE SHIFTING TO THE NE AND OUT OF NRN AZ SO THIS WILL DIMINISH
THE SEEDER-FEEDER PROCESS RESULTING IN DECREASED PCPN EFFICIENCY.
STRONG AND GUSTY WINDS WILL CONTINUE ACROSS THE EASTERN PORTION OF
THE STATE AND A WIND ADVISORY REMAINS IN EFFECT THROUGH LATE THIS
AFTERNOON.
&&
.PREV DISCUSSION (400 AM)...TONIGHT THE FRONTAL BOUNDARY STALLS TO
OUR SOUTHEAST WITH THE WHITE MOUNTAINS HAVING THE BEST CHANCES FOR
SHOWERS. QPF AMOUNTS ARE LOW THOUGH AND SNOWFALL ACCUMULATIONS IN THE
WHITES ARE LESS THAN ADVISORY CRITERIA AND WILL KEEP THIS AREA OUT OF
A WINTER WX ADVISORY. CLEARING WEATHER TO MOVE IN FROM NW TO
SOUTHEAST TONIGHT AND REACH THE WHITE MTNS THURSDAY AFTERNOON.
VERY COLD AFTERNOON TEMPERATURES ARE IN STORE THROUGH SUNDAY...
AROUND 20 DEGREES BELOW NORMAL.
DRY WEATHER FOR ALL FROM THURSDAY EVENING THROUGH SUNRISE SATURDAY.
ANOTHER SYSTEM LOOMS FOR SATURDAY AND SUNDAY. CROSS SECTION FROM
ECMWF AND GFS SHOW DEEP SATURATION WITH THIS SYSTEM AND SHOULD THE
LATEST QPF PROGS VERIFY WE WOULD BE HAVING MORE SNOW ACCUMULATION
THAN TODAY. TIMING DETAILS ARE COMING TOGETHER AND CONFIDENCE
AND PRECIP CHANCES ARE RISING. STAY TUNED.
&&
.AVIATION...FOR THE 18Z PACKAGE... A POTENT COLD FRONT POSITIONED
ACROSS NORTH CENTRAL AZ THIS MORNING WILL MOVE SOUTHEAST TODAY
BRINGING WIDESPREAD IFR-MVFR CONDITIONS. SCT LIFR CONDITIONS CAN BE
EXPECTED IN THE MAIN FRONTAL PRECIPITATION BAND. SFC WINDS GENERALLY
SW15-25G35KT...ESPECIALLY ACROSS EASTERN AZ. SNOW LEVELS WILL REMAIN
ABOVE 6000 FEET AHEAD OF THE FRONT...LOWERING TO 3500-4500 FEET
BEHIND THE FRONT. AFTER 14/00Z...IMPROVING CONDITIONS SPREADING FROM
WEST TO EAST ACROSS WITH WINDS BECOMING LIGHT. AVIATION DISCUSSION
NOT UPDATED FOR AMENDMENTS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR AZZ013-014-016-
017.
WINTER WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR
AZZ004.
WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR
AZZ015-016.
&&
$$
PUBLIC.........DB/DL
AVIATION.......MCS
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
855 PM EST THU DEC 5 2013
.DISCUSSION...
EVENING RUC ANALYSIS SHOWS DEEP LYR RIDGING CENTERED BTWN BERMUDA
AND THE NRN BAHAMAS. RIDGE AXIS DRAPED SW ACRS THE CENTRAL
PENINSULA...EXTENDING INTO THE BAY OF CAMPECHE. POSITION OF THE
RIDGE IS GENERATING A 10-15KT SE BREEZE THRU THE H100-H85 LYR OVER
CENTRAL AND S FL. THIS COMPONENT HAS ALLOWED A PERSISTENT BAND OF
WAKE CONVERGENCE SHRAS TO FORM ON THE LEE SIDE OF GRAND BAHAMA
ISLAND THAT HAS BEEN AFFECTING THE TREASURE COAST S OF VERO BEACH
FOR THE PAST SVRL HRS. SO FAR TODAY...RADAR ESTIMATES TOTAL RAINFALL
BTWN 0.50" AND 1.00" IN THE VCNTY OF THE ST. LUCIE NUCLEAR
PLANT...BTWN 0.10" AND 0.25" COMMON ARND FT PIERCE AND JENSEN
BEACH...THOUGH ALMOST NONE OF IT HAS FALLEN W OF I-95.
FEW CHANGES TO THE SYNOPTIC PATTERN OVERNIGHT...LIGHT BUT STEADY
SERLY BREEZE WILL KEEP TEMPS IN THE L/M60S OVER THE INTERIOR...M/U60
ALONG THE COAST...BTWN 10-15F ABV AVG. WITH NO AIRMASS CHANGE...
PATCHY FOG ALONG AN N OF THE I-4 CORRIDOR LOOKS REASONABLE GIVEN ITS
FORMATION THE PAST FEW MORNINGS. GIVEN ITS PERSISTENCE AS WELL AS
LATEST RADAR TREND...WILL EXPAND ISOLD SHRA COVERAGE TO ENCOMPASS
THE ENTIRE TREASURE COAST...CONTG OVERNIGHT.
&&
.AVIATION...
THRU 06/08Z...PREVAILING VFR ALL SITES...TEMPO MVFR VSBYS/CIGS IN
ISOLD COASTAL SHRAS S OF KVRB. BTWN 06/08Z-06/14Z...N OF KEVB-KISM
PATCHY MVFR/LCL IFR VSBYS IN BR AND IFR CIGS IN STRATUS...BRIEF PDS
OF LIFR FG VCNTY KLEE...S OF KEVB-KISM MVFR CIGS IN STRATUS AND
TEMPO MVFR VSBYS IN BR. AFT 06/14Z...VFR ALL SITES.
&&
.MARINE...
NO SIG CHANGES TO THE CURRENT WX PATTERN OR WITH THE EVNG UPDATE. HI
PRES RIDGE DRAPED OVER THE CENTRAL FL PENINSULA WILL MAINTAIN A
LIGHT TO GENTLE SERLY BREEZE ACRS THE LCL ATLC. SEAS 2-3FT WITH
DOMINANT PDS AOA 9SEC.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...VOLKMER
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
745 PM EST THU DEC 5 2013
.UPDATE (TONIGHT AND FRIDAY)...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWING A DEEP LONGWAVE TROUGH
IN PLACE ACROSS THE WESTERN STATES AND EXTENDING OVER THE NORTHERN
PLAINS. THE DOWNSTREAM FLOW THEN RIDGES UP FROM THE GULF OF MEXICO
INTO THE SOUTHEASTERN STATES AND THEN INTO THE WESTERN ATLANTIC. THE
TRANSITION ZONE BETWEEN THESE LONGWAVE FEATURES EXTENDING FROM THE
SOUTHERN PLAINS TO THE TN/OH VALLEYS IS THE "BATTLE GROUND" TONIGHT
WITH A VAST VARIETY OF INCLEMENT WEATHER...INCLUDING SOME
SIGNIFICANT ICE ACCUMULATIONS. THIS INCLEMENT WEATHER IS NOT IN OUR
FORECAST AS THE DOMINANT UPPER RIDGE OVER THE STATE WILL REMAIN IN
PLACE THROUGH FRIDAY...WITH A CONTINUATION OF THE ABOVE NORMAL
TEMPERATURES AND VERY LOW RAIN CHANCES.
AT THE SURFACE...RIDGE AXIS EXTENDS FROM THE WESTERN ATLANTIC
WESTWARD ACROSS THE FL PENINSULA AND EASTERN GULF OF MEXICO. THE
RIDGE AXIS IS GENERALLY JUST TO THE NORTH OF THE I-4 CORRIDOR
KEEPING A GENERAL LIGHT SOUTHEAST SYNOPTIC FLOW IN THE BOUNDARY
LAYER. DID SEE THE GRADIENT RELAX ENOUGH WITH THE STRONG TERRESTRIAL
HEATING TO ALLOW ANOTHER SEA-BREEZE...HOWEVER IT TOOK LONGER TODAY
TO BECOME ESTABLISHED...AND WILL BE FADING IN THE NEXT FEW HOURS.
A VERY SIMILAR SETUP IS EXPECTED THROUGH THE DAY ON FRIDAY. A WARM
AND DRY REST OF THE NIGHT CAN BE EXPECTED WITH LOW TEMPERATURES
STAYING IN THE 60S FOR MOST LOCATIONS. A FAIRLY MOIST BOUNDARY LAYER
ALONG WITH SOME DRIER AIR AND SUPPRESSION FROM ALOFT IS A DECENT
SETUP FOR FOG FORMATION AS WE HEAD DEEPER INTO THE OVERNIGHT. WOULD
NOT BE SURPRISED TO SEE SOME FAIRLY DENSE AREAS OF GROUND FOG BY THE
TIME OF THE MORNING COMMUTE...AND WILL CONTINUE TO MONITOR THE
SITUATION IN CASE ADVISORIES BECOME NECESSARY IN THE HOURS TO COME.
DURING FRIDAY...ANOTHER MIX OF SUN AND CLOUDS AND EXCELLENT DECEMBER
MIXING (DESPITE THE NEAR MINIMUM IN SOLAR STRENGTH) WILL AGAIN ALLOW
TEMPS TO MIX OUT INTO THE LOWER 80S FOR MANY SPOTS. THE MAV NUMBERS
HAVE BEEN A DEGREE OR 2 ON THE WARM SIDE WITH THIS RIDGE AND SO FEEL
LOWER 80S IS SHOULD BE MORE COMMON FRIDAY AFTERNOON. ALSO SIMILAR TO
WHAT OCCURRED ON THURSDAY. A LATE DAY SEA-BREEZE IS LIKELY TO GET
GOING ALONG THE IMMEDIATE COAST. THIS ONSHORE COMPONENT OFF THE
RELATIVELY COOLER SHELF WATERS SHOULD ACT TO DROP TEMPS BACK INTO
THE 70S BY LATE AFTERNOON AT THE BEACHES. HAVE A GREAT REST OF YOUR
EVENING!
&&
.AVIATION...
06/00Z-07/00Z...VFR WITH LIGHT SE WINDS GIVE WAY TO MVFR VSBY/CIGS
STARTING AT 08Z...WITH TEMPO IFR 09-13Z FROM PGD NORTHWARD. MAINLY
MVFR CIGS LATE MORNING BECOME VFR AFTER 18-19Z. SE WINDS FRI SHIFT
TO SOUTHERLY IN THE AFTERNOON.
&&
.MARINE...
HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE THROUGH EARLY
NEXT WEEK. A COLD FRONT WILL THEN MOVE THROUGH THE AREA NEXT
TUESDAY. WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW HEADLINE
THRESHOLDS THROUGH THE FORECAST PERIOD. SEA FOG COULD BECOME A
CONCERN BEGINNING LATE IN THE DAY FRIDAY AND CONTINUING THROUGH
EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 68 83 67 82 / 0 0 10 0
FMY 67 85 65 84 / 0 10 0 0
GIF 65 84 65 83 / 0 10 10 0
SRQ 65 82 65 82 / 0 10 10 0
BKV 61 84 59 84 / 0 10 10 0
SPG 68 82 68 81 / 0 0 10 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
955 AM EST WED DEC 4 2013
.DISCUSSION...
LATEST RUC ANALYSIS...MORNING SOUNDINGS...AND LCL WIND PROFILERS
TRACE OUT THE AXIS OF A BROAD HIGH PRES RIDGE DRAPED OVER THE S HALF
OF THE FL PENINSULA EXTENDING INTO THE SE GOMEX: S/SE WINDS THRU THE
H100-H85 LYR OVER S FL...BCMG SW OVER CNTRL AND N FL. MOISTURE THRU
THE COLUMN IS ON THE LOW SIDE...RANGING FM 1.0" AT KXMR TO 1.3" AT
KMFL. MODERATE UPSTREAM MOISTURE THRU THE H100-H85 LYR WITH MEAN RH
GENERALLY AOA 70PCT. HOWEVER...SUBSIDENCE INVERSIONS NOTED IN THE
H80-H70 LYR AS WELL AS THE H60-H45 LYR WILL KEEP THE LCL AIRMASS
WELL CAPPED.
LCL AIRMASS IS TOO DRY/STABLE TO PROMOTE ANY SHRA ACTIVITY OUTSIDE
OF THE GULF STREAM...AND ANY THAT DOES FORM WILL BE PUSHED OFFSHORE
BY THE PREVAILING SWRLY FLOW THRU THE H85-H50 LYR...FCST REMAINS
DRY. S/SWRLY WINDS WILL PUSH TEMPS INTO THE L/M80S OVER THE
INTERIOR...5-10F ABV AVG. TEMPS IN THE U70S/L80S ALONG THE COAST AS
A WEAK SFC PGRAD ALLOWS A SEA BREEZE TO FORM ALONG THE COAST BY MID
AFTN.
MRNG FCST PACKAGE LOOKS GOOD...NO NEED FOR UPDATES.
&&
.AVIATION...
VFR ALL SITES UNLESS OTHERWISE NOTED. BTWN 04/17Z-04/19Z...SFC
WNDSHFT FM S/SW TO SE AOB 10KTS CSTL SITES ASSOCD WITH THE EAST
COAST SEA BREEZE. BTWN 05/06Z-05/14Z...AREAS MVFR VSBYS/LCL IFR CIGS
IN BR AND STRATUS N OF KEVB-KISM...PTCHY MVFR VSBYS S OF KEVB-KISM
IN BR.
&&
.MARINE...
FAVORABLE BOATING CONDITIONS AS A BROAD HI PRES RIDGE CENTERED N OF
THE BAHAMAS BTWN BERMUDA AND THE CAROLINA COAST MAINTAINS A LIGHT TO
GENTLE S/SW BREEZE ACRS THE LCL ATLC. DATA BUOYS/C-MAN STATIONS
MEASURING SFC WINDS AOB 10KTS...SEAS AOB 2FT NEARSHORE AND 2-3FT
OFFSHORE WITH DOMINANT PDS AOA 8SEC. CURRENT FCST RUNNING A LITTLE
HIGH GIVEN THE CURRENT CONDITIONS...WILL LOWER SEAS BY A FOOT WITH
THE MORNING UPDATE.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...MOSES
AREA FORECAST DISCUSSION...UPDATE
NWS PEACHTREE CITY GA
1244 AM EST WED DEC 4 2013
.UPDATE...
/ISSUED AT 840 PM EST TUE DEC 3 2013/
HAVE MADE ADJUSTMENTS TO POP GRIDS THROUGH THE EVENING TO ACCOUNT
FOR REDEVELOPMENT OF RAIN ACROSS CENTRAL AND PARTS OF NORTH GA. LOW
LEVEL MOISTURE ADVECTION CONTINUES ACROSS THE REGION AND DEWPOINTS
ARE WELL INTO THE 50S TO LOWER 60S ACROSS CENTRAL AND PARTS OF NORTH
GA AND IN THE UPPER 40S AND 50S ACROSS THE REST OF NORTH GA. WITH
MOISTURE CONTINUING TO ADVECT...IT APPEARS TEMPS WILL REMAIN NEARLY
STEADY FOR THE REST OF THE NIGHT ACROSS THE CWA AND HAVE MADE THE
NECESSARY CHANGES TO TONIGHTS MIN TEMPS. RAIN SHOULD END FROM THE
WEST AFTER MIDNIGHT. SOME PATCHY DENSE FOG IS POSSIBLE AFTER
MIDNIGHT BUT AT THIS TIME WILL NOT ISSUE A DENSE FOG ADVISORY
HOWEVER WILL CONTINUE TO MONITOR THE SITUATION.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
/ISSUED AT 253 PM EST TUE DEC 3 2013/
WARM FRONT SHOULD BE MOVING NORTH THROUGH THE CWA THIS EVENING AND
OVERNIGHT. GFS/NAM KEEP ENHANCED MOISTURE ACROSS THE CWA THROUGH
WEDNESDAY MORNING...AND HRRR IS INDICATING AN EXPANSION OF THE RAIN
AREA AS IT MOVES NORTHEAST TONIGHT. HAVE KEPT LIKELY POPS OVER MUCH
OF THE CENTRAL TO NE ZONES WITH A GRADUAL DECREASE AFTER 06Z. SOME
LINGERING LOW POPS WEDNESDAY MORNING MAINLY NORTH. WEAK UPPER RIDGE
BUILDS OVER THE CWA WEDNESDAY AFTERNOON AND SO HAVE REMOVED THE POPS
FOR THAT TIME. STRONG SOUTHERLY FLOW WILL BRING ANOTHER INCREASE IN
MOISTURE TO THE CWA LATE WEDNESDAY NIGHT AHEAD OF AN APPROACHING
COLD FRONT. HAVE INTRODUCED POPS AGAIN TOWARD THURSDAY MORNING. AIR
MASS LOOKS STABLE FOR THE SHORT TERM...SO HAVE NO MENTION OF
THUNDER. INSTABILITY STARTS TO INCREASE BY 12Z THURSDAY. EXPECT WARM
TEMPERATURES WITH THE STRONG SOUTHERLY FLOW. OVERNIGHT MINS MAY
APPROACH RECORD VALUES.
41
.LONG TERM /THURSDAY THROUGH TUESDAY/...
/ISSUED AT 253 PM EST TUE DEC 3 2013/
ONLY MINOR CHANGES MADE TO THE EXTENDED WITH THIS PACKAGE. REFINED
TIMING OF POPS FOR EARLY THURSDAY AND MADE SOME MINOR ADJUSTMENTS
MAINLY TO LOW TEMPS THROUGH THE EXTENDED. GUIDANCE COMING INTO
SLIGHTLY BETTER AGREEMENT FOR THE FINAL FROPA AFTER THE WEEKEND
CAD EVENT /GFS COMING MUCH BETTER IN LINE WITH THE ECMWF/ SO MADE
SOME ADDITIONAL ADJUSTMENTS TO TEMPS EARLY NEXT WEEK...BUT OVERALL
VERY LITTLE CHANGE. STILL SOME CONCERN ABOUT THUNDERSTORMS
THURSDAY AND FRIDAY AFTERNOON...WITH INCREASING CONCERN FOR
ISOLATED SEVERE. SHERB VALUES HOVER JUST BELOW THE CRITICAL
THRESHOLD OF 1 FOR HIGH SHEAR LOW CAPE SEVERE WEATHER BOTH
AFTERNOONS AND SPC HAS ADDED A GENERAL THUNDER AREA FOR DAY 3
/THURSDAY/. WILL CONTINUE TO MONITOR EVOLUTION OF THE FORECAST.
TDP
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED AT 405 AM EST TUE DEC 3 2013/
AN UNSETTLED WEATHER PATTERN WILL PREDOMINATE FOR MUCH OF THE
EXTENDED PERIOD.
CHANCES FOR LIGHT RAIN WEDNESDAY NIGHT INCREASING OVER MAINLY N GA
AS AN INCREASINGLY WARM AND MOIST SOUTHERLY LOW LEVEL FLOW
CONTINUES AHEAD OF A SLOW MOVING COLD FRONT MOVING ACROSS THE MID
U.S.
THE GFS AND EUROPEAN ARE SIMILAR WITH BRINGING THE FRONT TO THE TN
VALLEY LATE THURSDAY WITH SHOWERS LIKELY FOR N AND PORTIONS OF
CENTRAL GA WITH SMALL CHANCES FOR THUNDERSTORMS. MUCAPE FORECAST IN
THE 200-600 RANGE. FOR THE MOST PART PRECIP EXPECTED TO BE LIGHT AND
POSSIBLY BRIEFLY MODERATE.
FRONT EXPECTED TO MOVE INTO N GA FRIDAY AND TO CENTRAL TO S GA LATE
SATURDAY. MAINLY SMALL THUNDERSTORM CHANCES ASSOCIATED AS AN AXIS OF
MUCAPE MOVES WITH THE FRONT INTO FRIDAY NIGHT BEFORE WEAKENING.
HIGHEST POPS EXPECTED TO BE OVER N GA FRIDAY/FRIDAY NIGHT. SATURDAY
POPS FOR CENTRAL GA MAY NOT BE HIGH ENOUGH WITH CHANCE SHOWERS
FORECAST.
THE TREND FOR MUCH WARMER TEMPERATURES WILL CONTINUE UNTIL THE FRONT
PASSES BY. EXPECTING NEAR-RECORD OR RECORD WARM MIN TEMPS FOR
FRIDAY MORNING.
WITH HIGH PRESSURE MOVING ACROSS THE NORTHERN STATES SATURDAY NIGHT
AND SUNDAY...GFS AND EUROPEAN ARE SIMILAR WITH FORECASTING A COLD
AIR DAMMING EVENT THAT WILL INCREASE RAIN CHANCES ACROSS N AND
PORTIONS OF CENTRAL GA. BY LATE DAY SUNDAY THE GFS AND EUROPEAN
BEGIN TO DIFFER THAT BECOMES EVEN GREATER THROUGH MONDAY. THE GFS
MOVES ANOTHER FRONT ACROSS THE AREA MONDAY DRYING THINGS OUT BY DAYS
END. THE EUROPEAN IS MUCH SLOWER WITH THE FRONT OVER NW GA AT DAYS
END MONDAY MAKING THE FORECAST HIGH UNCERTAIN.
BDL
&&
.AVIATION...
06Z UPDATE...
LIFR CIGS WITH AREAS OF DENSE FOG HAVE SETTLED IN OVER ATHENS AND
THE ATLANTA TAF SITES...WITH CSG AND MCN EXPECTED TO FOLLOW SOON.
THE LIFR-IFR CIGS WILL PERSIST THROUGH 16-17Z THIS MORNING...WITH A
SLOW IMPROVEMENT TO POSSIBLY LOW VFR CIGS BY 19-20Z TODAY. BUT THIS
WILL BE BRIEF AS MVFR CIGS RETURN BY 00-02Z THU...THEN BACK DOWN TO
LIFR BY 08-09Z THU MORN. EXPECT AREAS OF DENSE FOG AGAIN TONIGHT
WITH VISIBILITIES 1/2SM OR LESS BY 08-09Z AS WELL. NEAR CALM SE
WINDS THIS MORNING WILL BECOME SW BY 18-19Z WITH SPEEDS GENERALLY
7KTS OR LESS. A LIGHT SSE WIND WILL RETURN LATER TONIGHT.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON ALL ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 52 68 57 72 / 70 20 20 40
ATLANTA 55 69 62 72 / 60 20 20 50
BLAIRSVILLE 49 63 57 67 / 50 20 30 60
CARTERSVILLE 52 68 60 72 / 50 20 30 50
COLUMBUS 57 75 65 76 / 60 10 20 40
GAINESVILLE 50 65 59 69 / 60 20 30 50
MACON 55 74 61 75 / 70 10 20 30
ROME 53 69 61 73 / 50 20 40 60
PEACHTREE CITY 51 70 60 73 / 70 10 20 50
VIDALIA 57 76 59 76 / 40 10 10 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...41/39
LONG TERM....TDP
AVIATION...39
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
344 PM CST WED DEC 4 2013
.DISCUSSION...
340 PM CST
ACTIVE WEATHER PATTERN TO PERSIST INTO THE WEEKEND WITH FOG
PERSISTING AND SHOWERS THIS EVENING...MUCH COLDER AIR AND LIGHT
SNOW POSSIBLE FOR THE SOUTHEAST CWA THURSDAY NIGHT INTO
FRIDAY...AS WELL AS ANOTHER SYSTEM TO MOVE ACROSS THE AREA LATE
THIS WEEKEND INTO EARLY NEXT WEEK.
IN THE NEAR TERM...THE CWA REMAINS IN THE WARM SECTOR AS LOW
PRESSURE TO THE WEST CONTINUES TO LIFT NORTH/NORTHEAST ACROSS THE
REGION. IN THIS MUCH WARMER AIRMASS...WELL ABOVE NORMAL TEMPS IN
THE 50S HAVE SETTLED IN FOR MOST AREAS WITH HIGH DEWPOINT AIR
STILL STREAMING NORTH ACROSS THE REGION. DUE TO THIS WARM AND
MOIST AIRMASS...AREAS OF FOG AND DENSE FOG PERSIST AT THIS HOUR.
ALTHOUGH THERE HAS BEEN SOME IMPROVEMENT OVER THE LAST SEVERAL
HOURS...THIS IMPROVEMENT HAS OCCURRED OUTSIDE OF THE ADVISORY
AREA. IN THE ADVISORY AREA...NORTH CENTRAL AND NORTHEAST
ILLINOIS...DENSE FOG WITH VISIBILITY AT A QUARTER OF A MILE OR
LESS IS STILL IN PLACE. THE MOST DENSE FOG APPEARS TO BE CLOSER TO
THE ILLINOIS/WISCONSIN BORDER...AS WELL AS FOR AREAS NEAR THE LAKE
WHERE BOTH LOCATIONS ARE OBSERVING VISIBILITY NEAR ZERO. ONCE
AGAIN...AM NOT EXPECTING ANY CHANGES WITH CONDITIONS OVER THE NEXT
2-3 HOURS WITH THE CURRENT ADVISORY/LOCATION VERY MUCH VALID AT
THIS TIME. OUTSIDE OF THIS ADVISORY...LOCATIONS COULD STILL
OBSERVE AREAS OF FOG WITH VISIBILITY DROPPING AS LOW AS 1-3 MILES.
ALL FOG/LOW VIS SHOULD IMPROVE AROUND THE 00Z TIME FRAME AS FROPA
OCCURS IN THE 00-03 TIME FRAME...AND WITH ANY DENSER FOG LINGERING
ACROSS THE ILLINOIS NEARSHORE TO BEGIN PUSHING TO THE
NORTH/NORTHEAST AS WINDS VEER TO THE SOUTHWEST AND WEST THIS
EVENING. WEAK LARGE SCALE LIFT OWING TO STRONG WAA AND SUBTLE WEAK
MID LEVEL FEATURES WILL CONTINUE TO AID IN LIGHT SHOWER
DEVELOPMENT...AND ESPECIALLY WITH FROPA THIS EVENING. ALTHOUGH
ANYTHING THAT FALLS SHOULD BE LIGHT AND MORE SPORADIC IN NATURE.
DUE TO THIS...HAVE LEFT LOW CHANCE POPS FOR THIS AFTERNOON AND
EARLY EVENING...WITH CHANCES FOR SHOWERS DIMINISHING AFTER 9 PM
TONIGHT. AFTER THE DEPARTURE OF THE FOG/SHOWERS THIS EVENING...A
MUCH COLDER AIRMASS WILL BEGIN WORKING ITS WAY EAST ACROSS THE
REGION AND RESULT IN LOW TEMPS IN THE MID-UPPER 20S AND LOW 30S
TONIGHT.
AFTER ABOVE NORMAL TEMPS TODAY...BELOW NORMAL TEMPS AROUND 30 CAN
BE EXPECTED FOR MOST AREAS ON THURSDAY AS THIS MUCH COLDER AIRMASS
CONTINUES TO PUSH SOUTHEAST ACROSS THE AREA THROUGH THE AFTERNOON.
EXPECT LITTLE IMPROVEMENT IN CLOUD COVER WITH SOME AREAS ACROSS
NORTHERN ILLINOIS TRYING TO BECOME MORE PARTLY CLOUDY/PARTLY SUNNY
ON THURSDAY. ALTHOUGH...BROAD SOUTHWEST FLOW ALOFT WILL ALLOW FOR
A CONTINUE STREAM OF SHORT WAVE TROUGHS TOMORROW AND EVEN INTO
FRIDAY. THESE FEATURES AS WELL AS RESULTANT LOW/MID LEVEL
BAROCLINIC ZONE WILL ALLOW FOR DEVELOPING PRECIP AXIS TO THE SOUTH
TO INCH ITS WAY CLOSER TO THE FAR SOUTHERN CWA. LATEST TRENDS WITH
MODEL GUIDANCE WOULD KEEP ANY PRECIP/SNOW JUST TO THE SOUTH OF THE
CWA...BUT WITH SOME GUIDANCE STILL HINTING THAT THE FAR NORTHERN
EXTENT OF THIS PRECIP COULD REACH OUR SOUTHERN TIERS OF THE CWA.
SO TRENDED TOWARDS LOWERING POPS THURSDAY NIGHT INTO
FRIDAY...MAINLY FOR AREAS SOUTH OF A LINE FROM GIBSON CITY IN
ILLINOIS NORTHEAST TO RENSSELAER IN INDIANA...BUT DID NOT
COMPLETELY REMOVE THEM. WITH THE COLUMN SUFFICIENTLY COLD NOW AT
THIS TIME...ANY PRECIP WOULD BE ALL SNOW. IF THIS DOES REACH THE
CWA...CURRENT THINKING/GRIDS WOULD SUGGEST AT MOST A HALF INCH TO
AN INCH OF POSSIBLE SNOWFALL. WELL BELOW NORMAL TEMPS AND QUIET
WEATHER WILL THEN BE OBSERVED FRIDAY NIGHT INTO SATURDAY
NIGHT...WITH STEERING FLOW LIKELY TO KEEP ANY LAKE EFFECT PRECIP
JUST OUTSIDE OF THE AREA. THEN CONTINUE TO MONITOR THE NEXT SYSTEM
TO MOVE THROUGH THE REGION...WHICH WOULD BE SUNDAY INTO MONDAY.
GUIDANCE APPEARS TO HAVE A FAIRLY DECENT HANDLE ON THIS SYSTEM AND
IF CURRENT TRENDS CONTINUE...MOST AREAS COULD OBSERVE ACCUMULATING
SNOWFALL WITH SEVERAL INCHES OF SNOWFALL POSSIBLE.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CEILINGS...CONTINUED PREVAILING LOW END IFR TEMPO LIFR INTO LATE
AFTERNOON-EARLY EVENING...THEN IMPROVEMENT TO MVFR FOR REST OF
NIGHT.
* VISIBILITY...PREVAILING IFR IMPROVING TO MVFR INTO LATE
AFTERNOON-EARLY EVENING...THEN TO VFR MID EVENING AND BEYOND.
* PATCHY -DZ/-RA BECOMING MORE WIDESPREAD FOR MID AFTERNOON TO
EARLY EVENING.
* WIND SHIFT WITH COLD FRONTAL PASSAGE THIS EVENING BRINGING
MODERATELY GUSTY WINDS INTO THU.
TRS
//DISCUSSION...UPDATED 18Z...
SURFACE LOW BECOMING BETTER ORGANIZED 50SM S OF MSP AT 17Z WITH
ELONGATED PRESSURE FALL CENTER FROM E MN ACROSS W CENTRAL AND N
WI... MI U.P. AND LAKE SUPERIOR. MODELS TAKE THIS LOW NNE TO FAR
E CENTRAL MN AT 21Z AND TO TO FAR SE MN BY 18Z THEN NE TO NW-N
CENTRAL WI BY 00Z.
SE-SSE LOW LEVEL WINDS ACROSS THE LOCAL AREA CONTINUE TO ADVECT
WARMER BUT ALSO HIGHER DEW POINT AIR WITH SURFACE DEW POINT
DEPRESSIONS OF 0-1 DEG F OVER ALL BUT EXTREME S PORTIONS OF IL
AND IN. CONTINUED FEED OF THIS LOW DEW POINT DEPRESSION AIR
EXPECTED TO MAINTAIN RESTRICTED VSBY AND LOW CEILINGS UNTIL THE
SURFACE WINDS VEER A BIT TO S-SSW LATE AFTERNOON-EARLY EVENING AS
THE LOW MOVES TO N WI. THIS SLIGHT W COMPONENT TO THE LOW LEVEL
FLOW STARTS TO ADVECT IN SOMEWHAT GREATER DEW POINT DEPRESSIONS
WHICH IS EXPECTED TO RESULT IN SOME INCREASE IN VISIBILITY AND
CEILING HEIGHT.
A FEW PATCHES OF -DZ/-RA CURRENTLY MOVING NE AND FAR N CENTRAL
IL. MODELS CONTINUE TO SHOW PERSISTENT AND GRADUALLY INCREASING
BUT STILL SOMEWHAT WEAK UVV DOWN INTO THE LOW LEVEL MOISTURE
THROUGH EARLY EVENING AS A MID LEVEL SHORT WAVE TROUGH ROTATES NE
OVER THE MID MS VALLEY. EXPECT CURRENT LOW COVERAGE LIGHT LIQUID
PRECIP TO BECOME SOMEWHAT BROADER BY MID AFTERNOON IN RESPONSE TO
STRENGTHENING LOW LEVEL ISENTROPIC LIFT.
WITH THE LOW PROGGED TO MOVE TO W LAKE SUPERIOR BY 06Z THE
TRAILING COLD FRONT IS EXPECTED TO PUSH W TO E ACROSS THE LOCAL
AREA EARLY-MID EVENING. STRONG COLD AIR ADVECTION AND PRESSURE
RISES WILL RESULT IN INCREASING AND MODERATELY GUSTY WINDS BEHIND
THE FRONT. CURRENTLY...UPSTREAM WINDS BEHIND THE FRONT ARE OUT OF
THE NW BUT WITH THE LOW MOVING NNE AND AWAY FROM THE AREA TONIGHT
EXPECT LOCAL WINDS TO BE WSW-W. SUBSIDENCE AND DRYING FOLLOWING
FROPA SHOULD ALLOW CEILINGS TO RISE TO MVFR AS CURRENT OBSERVED
FROM NE OK TO SE NEB.
ANOTHER SHORT WAVE TROUGH PROGGED TO BE EXTENDING FROM N CENTRAL
WI SW TO S CENTRAL IA AT 05.18Z BUT WITH NO MID LEVEL MOISTURE TO
WORK WITH AND THE CONTINUED DECREASE IN LOW LEVEL MOISTURE AM
ANTICIPATING NO PRECIP WITH THIS DISTURBANCE AND ONLY CIRRUS
CEILINGS BY SUNRISE THU.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
*MEDIUM CONFIDENCE IN CIG TRENDS.
*MEDIUM CONFIDENCE IN VSBY TRENDS.
*HIGH CONFIDENCE IN WINDS THROUGH PERIOD INCLUDING TIMING OF WSHFT
WITH FROPA +/- 2HR.
*HIGH CONFIDENCE IN -SHRA/-RA OCCURRING THIS AFTERNOON AND THEN NO
PRECIP TONIGHT.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW...WITH SNOW LIKELY SUNDAY NIGHT.
MONDAY...SLT CHC SNOW. MVFR POSSIBLE.
TUESDAY...PRIMARILY VFR.
BMD
&&
.MARINE...
157 PM CST
THE VERY ACTIVE WEATHER PATTERN FOR LAKE MICHIGAN WILL CONTINUE FOR
THE NEXT SEVERAL DAYS. A DEEPENING LOW PRESSURE SYSTEM IS LIFTING
NORTHEAST THROUGH THE MIDDLE MISSISSIPPI VALLEY. AN ASSOCIATED WARM
FRONT EXTENDS EAST ACROSS THE NORTHERN PORTIONS OF THE LAKE WITH
STRONG EAST FLOW OVER THE FAR NORTHERN PORTION OF THE LAKE WITH
MODEST SELY-SLY FLOW OVER THE REMAINDER. UNSEASONABLE WARM...MOIST
AIR HAS OVERSPREAD RELATIVELY COOLER LAKE WATER...LEADING TO AREAS
OF DENSE FOG OVER THE NEARSHORE AND OPEN WATERS. A DENSE FOG
ADVISORY WILL REMAIN IN EFFECT FOR MUCH OF LAKE MICHIGAN WHILE IT
REMAINS UNDER THE INFLUENCE OF THE WARM...MOIST GENERALLY SOUTHERLY
FLOW. AS THE LOW TRACKS THROUGH WISCONSIN AND ACROSS LAKE SUPERIOR
TONIGHT...IT WILL DEEPEN RAPIDLY AS A STRONG COLD FRONT SWEEPS
ACROSS THE LAKE. WINDS WILL QUICKLY SHIFT FROM SLY TO WLY/NWLY
USHERING IN MUCH COLDER AIR OVERNIGHT TONIGHT AND THROUGH THE DAY
TOMORROW. NOT ONLY WILL THE WIND SHIFT AND INFLUX OF COOLER...DRIER
AIR HELP DISSIPATE THE FOG...THE STRONGEST COLD ADVECTION WILL
COINCIDE WITH THE MOST RAPID DEEPENING OF THE PARENT LOW. WHILE SLY
WINDS WILL STRENGTHEN TO JUST UNDER GALE FORCE AHEAD OF THE FRONT...
WINDS ARE EXPECTED TO REACH 35 KT...TO POSSIBLY 40 KT...GALES OVER
THE NORTHERN PORTIONS OF THE LAKE WHERE PRESSURE RISES WILL BE
STRONGEST IN THE WAKE OF THE LOW AS IT CONTINUES TO THE NORTHEAST.
SO...WILL UPGRADE THE GALE WATCH TO A WARNING. THE PRESSURE
GRADIENT AND PRESSURE RISES OVER THE SOUTHERN PORTIONS OF THE LAKE
WILL NOT BE QUITE AS STRONG...WITH ANOTHER ARCTIC HIGH BUILDING OUT
OF SWRN CANADA AND INTO CENTRAL PLAINS TONIGHT. ALSO...A WEAK RIDGE
AXIS ASSOCIATED WITH THE ARCTIC HIGH WILL POKE OVER THE SOUTHERN
PORTIONS OF THE LAKE LATE TONIGHT AND TOMORROW...WHICH WILL ALSO
HELP KEEP WINDS BELOW GALE FORCE. HOWEVER...THE GRADIENT SHOULD BE
STRONG ENOUGH TO SUPPORT 20-30KT WINDS...SO WILL KEEP THE SMALL
CRAFT ADVISORY IN EFFECT FOR THE NEARSHORE WATERS. THERE WILL BE
ANOTHER POTENTIAL PERIOD OF GALES FOR FRIDAY NIGHT AND INTO SATURDAY
AS THE ARCTIC HIGH BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY AND A
MID LEVEL IMPULSE DROPS OUT OF CANADA AND TRACKS ACROSS THE UPPER
GREAT LAKES. THIS POTENTIAL GALE EVENT IS A LITTLE LESS CERTAIN AS
IT WOULD BE HIGHLY DEPENDENT ON THE TRACK OF THE HIGH. IF THE HIGH
CENTER SLIDES MORE OVER THE OHIO VALLEY...THERE WILL BE A BETTER
CHANCE FOR NWLY GALES...BUT IF THE HIGH TAKES A MORE NORTHERLY
TRACK...THEN WINDS WOULD BE LIGHTER. WILL NOT ISSUE A HEADLINE FOR
THIS SECOND POTENTIAL GALE EVENT...BUT WILL CARRY THE POSSIBILITY IN
THE TEXT OF THE FORECAST.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020 UNTIL 6 PM
WEDNESDAY.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-
LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...9 PM WEDNESDAY TO 9 PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...11 PM
WEDNESDAY TO 3 PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ744-LMZ745...1 AM THURSDAY TO 4 AM
FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
219 PM CST Wed Dec 4 2013
.DISCUSSION...
ISSUED 220 PM CST Wed Dec 4 2013
Lots to talk about this afternoon with a change to winter almost
upon us. Models in general agreement with series of systems
through weekend. A Winter Storm Watch will be required for I-70
and southward for potential of 5-8 inches of snow.
SHORT TERM...Tonight through Friday
Sfc low now over North central Iowa will move northeast and swing
a cold front across Illinois overnight. Cold front is currently moving
across E Iowa and NW Missouri at this time with 15-25 degree
temperature drops and gusty northwest winds. Some partial
temporary clearing of low clouds and fog that has enveloped much
of the area today should be expected behind front. Much colder air
will blast into Illinois tonight and early Thursday with highs
20-30 degrees cooler than todays.
The front slows and stalls to our southeast as it becomes parallel
with the upper flow. A series of disturbances riding along the
front will produce several periods of precipition across southeast
Illinois late Thursday through Friday. Temperatures should be near
freezing by then. Although a brief period of freezing rain/sleet
at the onset is possible. Cold air should quickly change any
precip over to snow pretty quickly as 850 temps drop. NAM is a bit
slower in moving the coldest 850 temps in during the evening and
has a longer period of potential ZR/IP, but appears to be outlier.
Will follow closer to phase change timing suggested by ECMWF and
GFS.
Although mixing ratios are running 4-5 g/Kg, isentropic lift is not
very impressive. Warm ground may also lower amounts slightly early
on, but intensity of snow should overcome this limitation by
middle evening. Even with tempering snowfall amounts some, ECMWF
low-level temps and HPC precip guidance give snow amounts
approaching 8 inches south of U.S. 50. Will be issuing a Winter
Storm Watch for I-70 and southward for 5-8 inches of snow through
the event.
At this time it appears that there may be a lull between systems
Friday morning before precip picks up again Friday afternoon as
the next disturbance moves through and finally pushes the front
and its associated precip further east and out of Illinois late
Friday afternoon.
There looks like there will be a fairly quick cutoff to the
northwest of the precip shield as drier air advecting in will
erode the precip. Snow amounts will likely be light from
I-72/Danville northward with most locations northwest of a
Jacksonville/Lincoln/Bloomington line remaining dry.
LONG TERM...Friday Night through Wednesday
Colder air moves into the region behind the system dropping 850 mb
temps into the -7 to -11 C range. Wind chill temperatures will
likely range from around -5F along I-74 to just above zero south
of I-70 by Saturday morning.
As a trough digs along the west coast, we once again develop a
southwest flow above the cold boundary layer on Saturday Night and
by Sunday snow chances will once again manifest themselves with up
to an inch or two possible across much of the region in broad warm
advection pattern at 700-850 mb. Will have to watch this system
closely for potential for mixed precip with temperatures below freezing,
but for now will keep all snow.
Even colder temperatures are expected early next week as the
Hudson Bay Vortex deepens and brings another cold front across
Illinois Monday and Monday Night. 850 mb temps drop into the -10
to -15C range with wind chills below zero across the entire area
Tuesday morning.
Barker
&&
.AVIATION...
ISSUED 1132 AM CST Wed Dec 4 2013
LIFR conditions continue to plague the TAF sites at midday, with
locally lower conditions near KBMI which has persistent visibility
near 1/16SM. Should see some slow improvements with ceilings and
visibilities this afternoon as visible satellite and surface obs
show some higher ceilings heading northward. Fairly good sized
area of central/eastern Missouri has lost most of its low clouds,
and the latest RAP guidance suggests areas around KSPI/KDEC could
potentially reach into VFR range for a couple hours around midday.
For now will keep broken cloud cover around 2500 feet there
mid/late afternoon.
Strong cold front will sweep through central Illinois this
evening, swinging winds around to the southwest. Guidance from the
RAP and NAM models show VFR conditions becoming likely after 06Z.
Geelhart
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH from Thursday evening through Friday
afternoon FOR ILZ062-063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1219 PM CST WED DEC 4 2013
.DISCUSSION...
1046 AM CST
MAIN FORECAST CONCERNS FOR THIS MORNING UPDATE ARE WITH THE DENSE
FOG THAT REMAINS IN PLACE...CONTINUING AND EVEN EXPANDING THE
ADVISORY INTO 00Z TONIGHT.
HAVE EXTENDED THE DENSE FOG ADVISORY THRU 00Z TONIGHT AS DENSE FOG
PERSISTS THIS MORNING. AS LOW PRESSURE LIFTS NORTHEAST ACROSS THE
REGION...THE CWA CONTINUES TO OBSERVE STRONG MOISTURE AND TEMP
ADVECTION. THIS IS RESULTING IN WELL ABOVE NORMAL TEMPS...AND AN
ABUNDANCE OF MOISTURE ACROSS A GOOD PORTION OF THE REGION. INITIAL
THOUGHTS WERE TO LET THE ADVISORY EXPIRE THIS MORNING WITH
INCREASING DEW POINT DEPRESSIONS. ALTHOUGH WITH SLOWLY RISING
TEMPS THIS MORNING...DEW POINTS HAVE RISEN ALONG WITH THEM. AREAS
LIKELY TO OBSERVE PERSISTENT LOW DEW POINT DEPRESSIONS AND DENSE
FOG WERE FOR AREAS IN THE CURRENT ADVISORY. LATEST TRENDS THIS
MORNING AS WELL AS WEBCAMS SHOWED AREAS JUST OUTSIDE OF THE
ADVISORY FROM LA SALLE NORTHEAST TO COOK DID INDICATE THE MORE
DENSE FOG WAS PERSISTING...AND SO HAVE INCLUDED THEM IN THE
ADVISORY. ALTHOUGH FOR COOK...THE MORE LIKELY AREAS TO OBSERVE
THIS DENSE FOG WOULD BE ACROSS THE EAST AND NORTHEAST SIDES OF THE
COUNTY...WITH VERY MOIST CONDITIONS OVER THE LAKE AND A SOUTHEAST
WIND ALLOWING DENSE FOG TO AFFECT AREAS ALONG THE SHORE. WITH
SIMILAR CONDITIONS TO PERSIST ACROSS THE ENTIRE AREA UNTIL FROPA
AROUND THE 00Z TIME FRAME...FOG SHOULD PERSIST BUT WILL THEN
IMPROVE THIS EVENING WITH DRIER AIR FILTERING IN ON THE BACKSIDE
OF THIS SYSTEM.
RODRIGUEZ
//PREV DISCUSSION...
406 AM CST
FORECAST CONCERNS THIS MORNING FOCUS ON DENSE FOG TRENDS THIS
MORNING...AND TRENDS INTO THIS AFTERNOON WITH MILD TEMPS UNTIL COLD
FROPA LATE AFTERNOON/EVENING. COLDER AIR COMES IN TWO PUSHES...
FIRST BEHIND THE FRONT TONIGHT AND THEN A SECOND PUSH FRIDAY
NIGHT-SATURDAY AS ARCTIC HIGH BUILDS MORE SOLIDLY EAST ACROSS THE
GREAT LAKES REGION. COUPLE OF CHANCES OF SOME LIGHT ACCUMULATING
SNOW IN THE COMING DAYS...INITIALLY ACROSS FAR SOUTHEAST CWA LATE
THURSDAY INTO FRIDAY...AND AND ACROSS THE CWA SUNDAY-SUNDAY NIGHT.
EVEN COLDER PUSH OF ARCTIC AIR APPEARS HEADED FOR THE AREA BY THE
MIDDLE OF NEXT WEEK.
VERY MILD AND MOIST AIR MASS IN PLACE ACROSS THE REGION EARLY THIS
MORNING...WITH BOTH SFC TEMPS AND DEW POINTS IN THE 40S WITH VERY
SMALL DEPRESSIONS. DENSE FOG WITH VISIBILITY LESS THAN 1/2SM
CONTINUES ACROSS THE FAR NORTHERN IL COUNTIES ROUGHLY NORTH OF A
STERLING TO DEKALB AND WAUKEGAN LINE AS OF 330 AM CST...WITH A
SMALLER AREA OF DENSE FOG OVER EAST CENTRAL IL. HIGH-RES GUIDANCE
INCLUDING HOPWRF AND NARRE TIME-LAGGED ENSEMBLES INDICATE THERE MAY
BE SOME IMPROVEMENT IN VISIBILITY ACROSS THE NORTHERN COUNTIES THIS
MORNING...WHILE SOME ENSEMBLE MEMBERS EXPAND DENSE FOG ACROSS
CENTRAL IL PRIOR TO ABOUT 15Z AND THEN DECREASE COVERAGE. OBS AT
PNT-IKK AND RZL HAVE NOT SHOWN A SIGNIFICANT DOWNWARD TREND AT THIS
TIME. WILL LEAVE ONGOING DENSE FOG ADVISORY ACROSS THE NORTH AS
IS...AND WILL CONTINUE TO MONITOR TRENDS ACROSS THE SOUTH FOR THE
POSSIBILITY OF NEEDING A HEADLINE THERE. WHILE VISIBILITY MAY
IMPROVE SOMEWHAT...AREAS OF FOG WILL LIKELY STICK AROUND INTO THE
AFTERNOON BEFORE AN INCREASE IN SCATTERED SHOWER COVERAGE...WARMER
DAYTIME TEMPERATURES AND THE EVENTUAL COLD FRONTAL PASSAGE CLEAR
THINGS OUT THIS EVENING.
WHILE COLDER MORE TYPICAL EARLY WINTER WEATHER WILL SPREAD INTO THE
AREA TONIGHT/THURSDAY...THE DEPARTING COLD FRONT WILL SLOW AS IT
BECOMES PARALLEL WITH THE MID/UPPER FLOW AND MOVES INTO THE EASTERN
LAKES AND OHIO VALLEY OVER THE NEXT 24-36 HOURS. THIS WILL LIMIT THE
EXTENT OF THE COLD AIR INTRUSION BEHIND THE FRONT...AND WILL LEAVE
THE ELEVATED FRONTAL ZONE ACROSS CENTRAL IL AND NORTHERN INDIANA
INTO FRIDAY. GUIDANCE REMAINS FAIRLY SIMILAR IN BRINGING TWO
SEPARATE DISTURBANCES ALONG THIS BAROCLINIC ZONE WITH THE FIRST LATE
THURSDAY/THURSDAY NIGHT...AND THE OTHER DURING THE DAY ON FRIDAY.
REASONABLY SIMILAR QPF OUTPUT FROM THE VARIOUS MODELS OF THE
AVAILABLE GUIDANCE INDICATE THE POTENTIAL FOR GENERALLY LESS THAN AN
INCH OF SNOW ACROSS THE FAR SOUTHEAST TIER OF COUNTIES OF THE CWA
BEFORE THE SECOND SHORT WAVE DEPARTS LATE FRIDAY...WITH FLURRIES
PERHAPS AS FAR NORTH AS A PONTIAC-WHITING LINE. AFTER THIS SECOND
SLIGHTLY MORE AMPLIFIED WAVE DEPARTS...ARCTIC HIGH PRESSURE BUILDS
MORE ROBUSTLY EAST ACROSS MINNESOTA AND WISCONSIN FRIDAY NIGHT AND
SETS THE STAGE FOR CHILLY TEMPS IN THE SINGLE DIGITS AWAY FROM THE
CITY FRIDAY NIGHT...AND ONLY IN THE TEENS TO LOW 20S SATURDAY.
LONGER RANGE GUIDANCE ALSO REMAINS IN DECENT AGREEMENT IN BRINGING
ANOTHER SHORT WAVE INTO THE REGION SUNDAY-SUNDAY NIGHT...WITH SOME
SPREAD IN THE MODEL SOLUTIONS LOOKING A LITTLE MORE IN AGREEMENT
WITH THE NEW 00Z ECMWF SIMILAR TO THE GFS IN BRINGING LOW PRESSURE
THROUGH THE OHIO VALLEY DURING THAT TIME. LIGHT SNOW LOOKS TO COVER
MOST/ALL OF THE CWA WITH THIS SYSTEM...AND HAVE BUMPED POPS TO
LIKELY IN MOST AREAS.
ANOTHER SURGE OF ARCTIC AIR THEN LOOKS TO SPREAD INTO THE AREA
BEHIND THIS SYSTEM MONDAY-TUESDAY. BOTH ECMWF/GFS MOS GUIDANCE
SHOWING LOWS IN THE SINGLE DIGITS BY TUESDAY MORNING...WITH HIGHS
ONLY AROUND 12-15 TUESDAY. THIS IS IMPRESSIVE GIVEN STRONG CLIMO
WEIGHTING IN THE MOS BY DAY 7...SOME 22-25 DEGREES BELOW NORMAL FOR
HIGHS FOR EARLY DECEMBER. BRRR.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CEILINGS...CONTINUED PREVAILING LOW END IFR TEMPO LIFR INTO LATE
AFTERNOON-EARLY EVENING...THEN IMPROVEMENT TO MVFR FOR REST OF
NIGHT.
* VISIBILITY...PREVAILING IFR IMPROVING TO MVFR INTO LATE
AFTERNOON-EARLY EVENING...THEN TO VFR MID EVENING AND BEYOND.
* PATCHY -DZ/-RA BECOMING MORE WIDESPREAD FOR MID AFTERNOON TO
EARLY EVENING.
* WIND SHIFT WITH COLD FRONTAL PASSAGE THIS EVENING BRINGING
MODERATELY GUSTY WINDS INTO THU.
TRS
//DISCUSSION...UPDATED 18Z...
SURFACE LOW BECOMING BETTER ORGANIZED 50SM S OF MSP AT 17Z WITH
ELONGATED PRESSURE FALL CENTER FROM E MN ACROSS W CENTRAL AND N
WI... MI U.P. AND LAKE SUPERIOR. MODELS TAKE THIS LOW NNE TO FAR
E CENTRAL MN AT 21Z AND TO TO FAR SE MN BY 18Z THEN NE TO NW-N
CENTRAL WI BY 00Z.
SE-SSE LOW LEVEL WINDS ACROSS THE LOCAL AREA CONTINUE TO ADVECT
WARMER BUT ALSO HIGHER DEW POINT AIR WITH SURFACE DEW POINT
DEPRESSIONS OF 0-1 DEG F OVER ALL BUT EXTREME S PORTIONS OF IL
AND IN. CONTINUED FEED OF THIS LOW DEW POINT DEPRESSION AIR
EXPECTED TO MAINTAIN RESTRICTED VSBY AND LOW CEILINGS UNTIL THE
SURFACE WINDS VEER A BIT TO S-SSW LATE AFTERNOON-EARLY EVENING AS
THE LOW MOVES TO N WI. THIS SLIGHT W COMPONENT TO THE LOW LEVEL
FLOW STARTS TO ADVECT IN SOMEWHAT GREATER DEW POINT DEPRESSIONS
WHICH IS EXPECTED TO RESULT IN SOME INCREASE IN VISIBILITY AND
CEILING HEIGHT.
A FEW PATCHES OF -DZ/-RA CURRENTLY MOVING NE AND FAR N CENTRAL
IL. MODELS CONTINUE TO SHOW PERSISTENT AND GRADUALLY INCREASING
BUT STILL SOMEWHAT WEAK UVV DOWN INTO THE LOW LEVEL MOISTURE
THROUGH EARLY EVENING AS A MID LEVEL SHORT WAVE TROUGH ROTATES NE
OVER THE MID MS VALLEY. EXPECT CURRENT LOW COVERAGE LIGHT LIQUID
PRECIP TO BECOME SOMEWHAT BROADER BY MID AFTERNOON IN RESPONSE TO
STRENGTHENING LOW LEVEL ISENTROPIC LIFT.
WITH THE LOW PROGGED TO MOVE TO W LAKE SUPERIOR BY 06Z THE
TRAILING COLD FRONT IS EXPECTED TO PUSH W TO E ACROSS THE LOCAL
AREA EARLY-MID EVENING. STRONG COLD AIR ADVECTION AND PRESSURE
RISES WILL RESULT IN INCREASING AND MODERATELY GUSTY WINDS BEHIND
THE FRONT. CURRENTLY...UPSTREAM WINDS BEHIND THE FRONT ARE OUT OF
THE NW BUT WITH THE LOW MOVING NNE AND AWAY FROM THE AREA TONIGHT
EXPECT LOCAL WINDS TO BE WSW-W. SUBSIDENCE AND DRYING FOLLOWING
FROPA SHOULD ALLOW CEILINGS TO RISE TO MVFR AS CURRENT OBSERVED
FROM NE OK TO SE NEB.
ANOTHER SHORT WAVE TROUGH PROGGED TO BE EXTENDING FROM N CENTRAL
WI SW TO S CENTRAL IA AT 05.18Z BUT WITH NO MID LEVEL MOISTURE TO
WORK WITH AND THE CONTINUED DECREASE IN LOW LEVEL MOISTURE AM
ANTICIPATING NO PRECIP WITH THIS DISTURBANCE AND ONLY CIRRUS
CEILINGS BY SUNRISE THU.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
*MEDIUM CONFIDENCE IN CIG TRENDS.
*MEDIUM CONFIDENCE IN VSBY TRENDS.
*HIGH CONFIDENCE IN WINDS THROUGH PERIOD INCLUDING TIMING OF WSHFT
WITH FROPA +/- 2HR.
*HIGH CONFIDENCE IN -SHRA/-RA OCCURRING THIS AFTERNOON AND THEN NO
PRECIP TONIGHT.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW...WITH SNOW LIKELY SUNDAY NIGHT.
MONDAY...SLT CHC SNOW. MVFR POSSIBLE.
TUESDAY...PRIMARILY VFR.
BMD
&&
.MARINE...
239 AM CST
MODELS ARE FINALLY SYNCED UP ON DEEPENING LOW PRESSURE WHICH IS
EXPECTED TO LIFT ACROSS WISCONSIN LATE THIS AFTERNOON...AND ACROSS
LATE SUPERIOR TONIGHT. MODERATE EASTERLY FLOW AROUND 30 KTS IS
EXPECTED NORTH OF A WARM FRONT STRADDLING THE MID SECTION OF THE
LAKE THIS MORNING...WITH STABLE SOUTHEASTERLY FLOW ACROSS THE SOUTH
OF THE FRONT. MID/UPPER 40 DEWPOINTS ADVECTING OVER THE LOW/MID 40
DEGREE WATER TEMPERATURES IS EXPECTED TO RESULT IN WIDESPREAD DENSE
FOG. A DENSE FOG ADVISORY IS IN EFFECT ACROSS THE SOUTH HALF OF THE
LAKE...BUT MAY NEED TO BE EXTENDED NORTH AS THE FRONT LIFTS ACROSS
THE REMAINDER OF THE LAKE. OVERNIGHT A COLD FRONT WILL SWEEP ACROSS
THE LAKE WITH WINDS TURNING WESTERLY BEHIND. STRONG COLD ADVECTION
WILL HELP TO MIX DOWN GALES...PRIMARILY ACROSS THE NORTH END OF THE
LAKE WHERE THE GRADIENT IS TIGHTEST...THOUGH APPEARS FOR NOW TO BE
LOW END GALE EVENT. A GALE WATCH REMAINS IN EFFECT FOR THE NORTH
PORTIONS OF THE LAKE. A STRONG HIGH WILL SETTLE ACROSS THE NORTHERN
PLAINS FRIDAY THOUGH LATE SATURDAY RESULTING IN WINDS STAYING
ELEVATED IN THE 20 TO 25 KT RANGE...WITH A FEW PERIODS OF 30 KTS.
ANOTHER LOW IS EXPECTED TO LIFT FROM THE LOWER MISSISSIPPI VALLEY
INTO THE EASTERN LAKES REGION EARLY NEXT WEEK.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020 UNTIL 6 PM
WEDNESDAY.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...3 AM THURSDAY TO 3 PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...11 PM
WEDNESDAY TO 3 PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ744-LMZ745...1 AM THURSDAY TO 4 AM
FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1132 AM CST Wed Dec 4 2013
.DISCUSSION...
ISSUED 1000 AM CST Wed Dec 4 2013
Dense fog starting to slowly lift in some areas. Have lopped off a
few counties from the advisory from Springfield westward where
visibility has been more persistently around a mile or so. Seeing
some variable visibilities from Peoria northwest and also over the
southeast counties, and will evaluate over the next hour whether
to drop the advisory there too or let it ride until its natural
conclusion at noon. HRRR model showing a more persistent lifting
of the dense fog over the next couple hours, although the RAP
lingers it east of I-57 into early afternoon.
Latest surface map shows low pressure over central Missouri, with
a secondary low over south central Iowa which should become the
primary low late today. Should start seeing the cold front moving
into the Illinois River valley toward 5-6 pm and across most of
the CWA by 10 pm.
Geelhart
&&
.AVIATION...
ISSUED 1132 AM CST Wed Dec 4 2013
LIFR conditions continue to plague the TAF sites at midday, with
locally lower conditions near KBMI which has persistent visibility
near 1/16SM. Should see some slow improvements with ceilings and
visibilities this afternoon as visible satellite and surface obs
show some higher ceilings heading northward. Fairly good sized
area of central/eastern Missouri has lost most of its low clouds,
and the latest RAP guidance suggests areas around KSPI/KDEC could
potentially reach into VFR range for a couple hours around midday.
For now will keep broken cloud cover around 2500 feet there
mid/late afternoon.
Strong cold front will sweep through central Illinois this
evening, swinging winds around to the southwest. Guidance from the
RAP and NAM models show VFR conditions becoming likely after 06Z.
Geelhart
&&
.PREV DISCUSSION...
ISSUED 311 AM CST Wed Dec 4 2013
Main forecast concern continues to be potential for accumulating
snow and ice across parts of central Illinois late Thursday into
Friday.
SHORT TERM...Today through Friday
Widespread fog once again blankets the area early this morning.
Moist low-level airmass remains in place, with 08z/2am surface
dewpoints well into the 40s. This ample moisture combined with
light winds will allow visibilities to continue to drop over the
next couple of hours. NAM/GFS forecast soundings and latest HRRR
visby forecast all point to widespread dense fog through much of
the morning. Will therefore be issuing a Dense Fog Advisory for
the entire KILX CWA through midday. Fog will gradually dissipate
by early afternoon, although visibilities will continue to be
somewhat limited until cold front pushes through late this
afternoon into the evening. Despite FROPA later today, shallow
moisture below 5000ft will limit precip potential. Will therefore
only mention isolated showers today into this evening. High
temperatures will be quite a bit warmer than they were yesterday,
but will be tempered by the fog/clouds to some extent. Will go
near or slightly above MAV guidance numbers, but not as high as
the warmer MET. Resulting highs will mainly be in the upper 50s
and lower 60s.
Once front passes, much colder air will arrive tonight into
Thursday. Overnight lows will drop into the upper 20s and lower
30s across much of the area, but will remain in the upper 30s
further east near the Indiana border. High temperatures on
Thursday will not rise much from the early morning lows, with
readings ranging from the upper 20s along/west of the Illinois
River to around 40 degrees along the Wabash River.
Models are in good agreement with the development of wintry precip
across parts of central and southeast Illinois late Thursday into
Friday, with a few minor differences still remaining. NAM has
slowed the onset of precip until early evening, while GFS/ECMWF/GEM
still bring it in during the afternoon. Given drier airmass behind
departing front, think NAM may have the right idea. Will therefore
delay initial precip development until late afternoon, with main
push arriving during the evening. Airmass will be cold enough to
support snow across most of the area: however, warm layer aloft
with max temps of around 4C supports mixed phase precip along and
south of I-70. Late afternoon surface temps in the upper 30s to
around 40 will allow for mainly rain along and south of highway
50. As the evening progresses, deepening cold layer will allow for
a gradual change over to mainly snow across the SE KILX CWA
overnight, although areas along and south of highway 50 may
experience a period of freezing rain as surface temps dip below
32 degrees. Any icing will be minimal, as precip transitions to
snow/sleet after midnight.
Initial wave of precip wanes after midnight, followed by another
wave on Friday. Model differences here focus on how far into the
cold airmass to spread the precip. NAM is most aggressive, while
GFS remains further southeast. Given strength of approaching high
within the cold airmass, think GFS solution is most logical. As a
result, will focus highest POPs for snow across the E/SE CWA. Once
the wintry precip ends Friday afternoon, total snowfall
accumulations of 3 to 5 inches will be likely along and south of
I-70. Amounts will steadily decrease further northwest, with up
to 1 inch possible along a Jacksonville to Danville line. Further
north, only a few flurries are expected along and north of a
Rushville to Bloomington-Normal line.
LONG TERM...Saturday through Tuesday
Cold weather will prevail throughout the extended, with only a brief
moderation in temps expected on Sunday. Models continue to show
another short-wave trough digging southward into the western
CONUS this weekend, resulting in downstream ridging over the
southeast states. As flow becomes more southwesterly aloft,
frontal boundary along the Gulf Coast will get pushed back
northward Sunday into Monday. It appears deepest moisture and
highest precip chances will remain southeast of Illinois across
the Tennessee and Ohio River Valleys, although the GFS is slightly
more aggressive in bringing precip further northwest into the cold
air than the ECMWF. At this point, will trend toward the ECMWF and
will only feature low chance POPs for snow Sunday and Sunday night
with minimal accumulations. After that, another very cold airmass
will drop into the Midwest by early next week, resulting in high
temps in the teens by Tuesday.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY until Noon CST today FOR ILZ027>031-036>038-
041>045-053.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1042 AM CST WED DEC 4 2013
.DISCUSSION...
406 AM CST
FORECAST CONCERNS THIS MORNING FOCUS ON DENSE FOG TRENDS THIS
MORNING...AND TRENDS INTO THIS AFTERNOON WITH MILD TEMPS UNTIL COLD
FROPA LATE AFTERNOON/EVENING. COLDER AIR COMES IN TWO PUSHES...
FIRST BEHIND THE FRONT TONIGHT AND THEN A SECOND PUSH FRIDAY
NIGHT-SATURDAY AS ARCTIC HIGH BUILDS MORE SOLIDLY EAST ACROSS THE
GREAT LAKES REGION. COUPLE OF CHANCES OF SOME LIGHT ACCUMULATING
SNOW IN THE COMING DAYS...INITIALLY ACROSS FAR SOUTHEAST CWA LATE
THURSDAY INTO FRIDAY...AND AND ACROSS THE CWA SUNDAY-SUNDAY NIGHT.
EVEN COLDER PUSH OF ARCTIC AIR APPEARS HEADED FOR THE AREA BY THE
MIDDLE OF NEXT WEEK.
VERY MILD AND MOIST AIR MASS IN PLACE ACROSS THE REGION EARLY THIS
MORNING...WITH BOTH SFC TEMPS AND DEW POINTS IN THE 40S WITH VERY
SMALL DEPRESSIONS. DENSE FOG WITH VISIBILITY LESS THAN 1/2SM
CONTINUES ACROSS THE FAR NORTHERN IL COUNTIES ROUGHLY NORTH OF A
STERLING TO DEKALB AND WAUKEGAN LINE AS OF 330 AM CST...WITH A
SMALLER AREA OF DENSE FOG OVER EAST CENTRAL IL. HIGH-RES GUIDANCE
INCLUDING HOPWRF AND NARRE TIME-LAGGED ENSEMBLES INDICATE THERE MAY
BE SOME IMPROVEMENT IN VISIBILITY ACROSS THE NORTHERN COUNTIES THIS
MORNING...WHILE SOME ENSEMBLE MEMBERS EXPAND DENSE FOG ACROSS
CENTRAL IL PRIOR TO ABOUT 15Z AND THEN DECREASE COVERAGE. OBS AT
PNT-IKK AND RZL HAVE NOT SHOWN A SIGNIFICANT DOWNWARD TREND AT THIS
TIME. WILL LEAVE ONGOING DENSE FOG ADVISORY ACROSS THE NORTH AS
IS...AND WILL CONTINUE TO MONITOR TRENDS ACROSS THE SOUTH FOR THE
POSSIBILITY OF NEEDING A HEADLINE THERE. WHILE VISIBILITY MAY
IMPROVE SOMEWHAT...AREAS OF FOG WILL LIKELY STICK AROUND INTO THE
AFTERNOON BEFORE AN INCREASE IN SCATTERED SHOWER COVERAGE...WARMER
DAYTIME TEMPERATURES AND THE EVENTUAL COLD FRONTAL PASSAGE CLEAR
THINGS OUT THIS EVENING.
WHILE COLDER MORE TYPICAL EARLY WINTER WEATHER WILL SPREAD INTO THE
AREA TONIGHT/THURSDAY...THE DEPARTING COLD FRONT WILL SLOW AS IT
BECOMES PARALLEL WITH THE MID/UPPER FLOW AND MOVES INTO THE EASTERN
LAKES AND OHIO VALLEY OVER THE NEXT 24-36 HOURS. THIS WILL LIMIT THE
EXTENT OF THE COLD AIR INTRUSION BEHIND THE FRONT...AND WILL LEAVE
THE ELEVATED FRONTAL ZONE ACROSS CENTRAL IL AND NORTHERN INDIANA
INTO FRIDAY. GUIDANCE REMAINS FAIRLY SIMILAR IN BRINGING TWO
SEPARATE DISTURBANCES ALONG THIS BAROCLINIC ZONE WITH THE FIRST LATE
THURSDAY/THURSDAY NIGHT...AND THE OTHER DURING THE DAY ON FRIDAY.
REASONABLY SIMILAR QPF OUTPUT FROM THE VARIOUS MODELS OF THE
AVAILABLE GUIDANCE INDICATE THE POTENTIAL FOR GENERALLY LESS THAN AN
INCH OF SNOW ACROSS THE FAR SOUTHEAST TIER OF COUNTIES OF THE CWA
BEFORE THE SECOND SHORT WAVE DEPARTS LATE FRIDAY...WITH FLURRIES
PERHAPS AS FAR NORTH AS A PONTIAC-WHITING LINE. AFTER THIS SECOND
SLIGHTLY MORE AMPLIFIED WAVE DEPARTS...ARCTIC HIGH PRESSURE BUILDS
MORE ROBUSTLY EAST ACROSS MINNESOTA AND WISCONSIN FRIDAY NIGHT AND
SETS THE STAGE FOR CHILLY TEMPS IN THE SINGLE DIGITS AWAY FROM THE
CITY FRIDAY NIGHT...AND ONLY IN THE TEENS TO LOW 20S SATURDAY.
LONGER RANGE GUIDANCE ALSO REMAINS IN DECENT AGREEMENT IN BRINGING
ANOTHER SHORT WAVE INTO THE REGION SUNDAY-SUNDAY NIGHT...WITH SOME
SPREAD IN THE MODEL SOLUTIONS LOOKING A LITTLE MORE IN AGREEMENT
WITH THE NEW 00Z ECMWF SIMILAR TO THE GFS IN BRINGING LOW PRESSURE
THROUGH THE OHIO VALLEY DURING THAT TIME. LIGHT SNOW LOOKS TO COVER
MOST/ALL OF THE CWA WITH THIS SYSTEM...AND HAVE BUMPED POPS TO
LIKELY IN MOST AREAS.
ANOTHER SURGE OF ARCTIC AIR THEN LOOKS TO SPREAD INTO THE AREA
BEHIND THIS SYSTEM MONDAY-TUESDAY. BOTH ECMWF/GFS MOS GUIDANCE
SHOWING LOWS IN THE SINGLE DIGITS BY TUESDAY MORNING...WITH HIGHS
ONLY AROUND 12-15 TUESDAY. THIS IS IMPRESSIVE GIVEN STRONG CLIMO
WEIGHTING IN THE MOS BY DAY 7...SOME 22-25 DEGREES BELOW NORMAL FOR
HIGHS FOR EARLY DECEMBER. BRRR.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* CEILINGS...CONTINUED PREVAILING LOW END IFR NTO LATE AFTERNOON-
EARLY EVENING...THEN SLIGHT IMPROVEMENT TO LOW END MVFR FOR
REST OF NIGHT.
* VISIBILITY...PREVAILING HIGH END IFR CAT-LOW END MVFR CAT INTO
EARLY EVENING IMPROVING TO MVFR INTO LATE AFTERNOON-EARLY
EVENING...THEN VFR MID EVENING AND BEYOND.
* PATCHY -DZ/-RA THROUGH EARLY AFTERNOON THEN BECOMING MORE
WIDESPREAD FOR MID AFTERNOON TO EARLY EVENING.
* WIND SHIFT THIS EVENING WITH COLD FRONTAL PASSAGE.
TRS
//DISCUSSION...UPDATED 16Z...
SURFACE LOW BECOMING BETTER ORGANIZED JUST NE OF DSM WITH PRES
FALL CENTER OVER SE NM AND W CENTRAL TO NW WI. MODELS TAKE THIS
LOW TO FAR SE MN BY 18Z AND N WI BY 00Z. SE-SSE LOW LEVEL WINDS
ACROSS THE LOCAL AREA ARE ADVECTING IN WARMER BUT ALSO HIGHER DEW
POINT AIR. WITH SURFACE DEW POINT DEPRESSIONS OF 0-1 DEG F
CURRENTLY MOVING OVER THE LOCAL AREA AND EXTENDING WELL UPSTREAM
ACROSS ALL BUT FAR S PORTIONS OF IL AND IN. THIS IS EXPECTED TO
MAINTAIN RESTRICTED VSBY AND LOW CIGS UNTIL LOW REACHES N WI AND
LOCAL SURFACE WIND VEERS A BIT TO S-SSE IN RESPONSE WHICH WILL
DELIVER SOMEWHAT GREATER DEW POINT DEPRESSIONS TO THE LOCAL AREA.
A FEW PATCHES OF -DZ/-RA HAVE RECENTLY MOVED OVER AND N OF ORD AND
MDW. MODELS CONTINUE TO SHOW SOME WEAK BUT PERSISTENT UVV DOWN
INTO THE LOW LEVEL MOISTURE TIL EARLY EVENING. FEW MORE WEAK RADAR
ECHOES MOVING N AND APPROACHING I-80. EXPECT LOW COVERAGE BEFORE
INCREASING MID AFTERNOON.
WITH LOW PROGGED TO MOVE TO OVER/NEAR CENTRAL U.P. OF MI BY 06Z
THE TRAILING COLD FRONT IS EXPECTED TO PUSH W TO E ACROSS THE
LOCAL AREA EARLY-MID EVENING.
TRS
PREVIOUS DISCUSSION...
THIS MORNING...A WARM FRONT LIES JUST NORTH OF THE TERMINALS WITH
SOUTHEAST FLOW AND IFR CONDITIONS IN PLACE ACROSS NORTHERN ILLINOIS
AND NORTHWEST INDIANA. WILL DISCUSS EACH FORECAST ELEMENT
INDIVIDUALLY...
CEILINGS...AS MENTIONED MOST OF THE REGION IS UNDER IFR CIGS THIS
MORNING...THOUGH THERE IS A HOLE IN THE LOWER CIGS THAT STRETCHES
FROM SW MICHIGAN INTO THE SOUTH CHICAGO METRO. GYY HAS MAINTAINED
VFR LEVEL CIGS FOR THE PAST SEVERAL HOURS...AND MDW HAS BEEN IN AND
OUT OF THE IFR CIGS. NAM/HRRR GUIDANCE TO SOME DEGREE HINTING AT
THIS HOLE...WHICH COULD BRIEFLY MOVE OVER ORD THIS MORNING. BOTH
MODELS DO SHOW THE HOLE FILLING IN THOUGH LATE THIS MORNING...SO ANY
TEMPO HIGHER CIGS WILL BE SHORT LIVED THIS MORNING. A SECONDARY WARM
FRONTAL LIKE FEATURE WILL LIFT ACROSS THE AREA THIS AFTERNOON...WITH
WINDS VEERING TO THE S OR SSW. MODELS INDICATE SOME IMPROVEMENT IN
CIGS POSSIBLE AFTER IT PASSES NORTH OF THE TERMINALS...THOUGH THE
DEGREE OF IMPROVEMENT IS UNCERTAIN. IT IS POSSIBLE WE MAY LIFT TO
MVFR AT THIS POINT...BUT WILL ERR ON THE SIDE OF LOWER CIGS FOR NOW
WHICH FITS WELL WITH LAV/MET GUIDANCE. BETTER CHANCE TO LIFT TO MVFR
WILL BE LATER IN THE EVENING AS A COLD FRONT SWEEPS ACROSS THE AREA.
EXPECT THE CIGS TO GRADUALLY RISE OVERNIGHT AS THE COLD AIR ERODES
THE CLOUD BASES.
VISIBILITY...VSBY RANGES FROM NEAR ZERO TO AROUND 4-5SM. DENSEST FOG
IS GENERALLY ALONG AND NEAR THE WARM FRONT AND THIS AREA SHOULD STAY
NORTH OF THE CHICAGO TERMINALS...THOUGH WILL CONTINUE TO IMPACT RFD
THROUGH THE MORNING. MODEL GUIDANCE IS ALL OVER THE PLACE WITH
RESPECT TO VSBY TRENDS TODAY. SEVERAL MODELS HINT THAT AS THE
SECONDARY BOUNDARY SOUTH OF THE AREA LIFTS NORTH...LOWER VSBY WILL
ALSO SPREAD NORTH INTO THE CHICAGO METRO. THERE IS ALREADY DENSE FOG
ACROSS PORTIONS OF EAST CENTRAL ILLINOIS...AND WILL HAVE TO MONITOR
THIS AREA CLOSELY AS IT MAY SPREAD NORTH OVER THE TERMINALS...BUT
FOR NOW GIVEN THE LOW CONFIDENCE...WILL STICK CLOSE TO MAV/LAV
TRENDS WHICH HOLD VSBY PRIMARILY MVFR FOR THE CHICAGO TERMINALS
TODAY. ANY PRECIP THAT DEVELOPS THIS AFTERNOON MAY ALSO CAUSE THE
VSBY TO DROP TO IFR.
WINDS...PRIMARILY SOUTHEASTERLY WINDS 6-10KTS ARE EXPECTED THIS
MORNING BEHIND THE FRONT NEAR THE STATE LINE THIS MORNING. WINDS
WILL EVENTUALLY VEER TO THE SOUTH/SSW AS THE SECOND BOUNDARY LIFTS
ACROSS THE AREA MID TO LATE THIS AFTERNOON. LATE THIS EVENING A COLD
FRONT WILL SWEEP ACROSS THE AREA WITH WINDS TURNING WESTERLY...AND
INCREASING WITH GUSTS INTO THE HIGH TEENS EXPECTED OVERNIGHT.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
*MEDIUM CONFIDENCE IN CIG TRENDS.
*MEDIUM CONFIDENCE IN VSBY TRENDS.
*HIGH CONFIDENCE IN WINDS INTO MID EVENING...THEN MODERATE
CONFIDENCE REST OF PERIOD.
*MEDIUM CONFIDENCE IN -SHRA/-RA OCCURRENCE THIS AFTERNOON.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW...WITH SNOW LIKELY SUNDAY NIGHT.
MONDAY...SLT CHC SNOW. MVFR POSSIBLE.
TUESDAY...PRIMARILY VFR.
BMD
&&
.MARINE...
239 AM CST
MODELS ARE FINALLY SYNCED UP ON DEEPENING LOW PRESSURE WHICH IS
EXPECTED TO LIFT ACROSS WISCONSIN LATE THIS AFTERNOON...AND ACROSS
LATE SUPERIOR TONIGHT. MODERATE EASTERLY FLOW AROUND 30 KTS IS
EXPECTED NORTH OF A WARM FRONT STRADDLING THE MID SECTION OF THE
LAKE THIS MORNING...WITH STABLE SOUTHEASTERLY FLOW ACROSS THE SOUTH
OF THE FRONT. MID/UPPER 40 DEWPOINTS ADVECTING OVER THE LOW/MID 40
DEGREE WATER TEMPERATURES IS EXPECTED TO RESULT IN WIDESPREAD DENSE
FOG. A DENSE FOG ADVISORY IS IN EFFECT ACROSS THE SOUTH HALF OF THE
LAKE...BUT MAY NEED TO BE EXTENDED NORTH AS THE FRONT LIFTS ACROSS
THE REMAINDER OF THE LAKE. OVERNIGHT A COLD FRONT WILL SWEEP ACROSS
THE LAKE WITH WINDS TURNING WESTERLY BEHIND. STRONG COLD ADVECTION
WILL HELP TO MIX DOWN GALES...PRIMARILY ACROSS THE NORTH END OF THE
LAKE WHERE THE GRADIENT IS TIGHTEST...THOUGH APPEARS FOR NOW TO BE
LOW END GALE EVENT. A GALE WATCH REMAINS IN EFFECT FOR THE NORTH
PORTIONS OF THE LAKE. A STRONG HIGH WILL SETTLE ACROSS THE NORTHERN
PLAINS FRIDAY THOUGH LATE SATURDAY RESULTING IN WINDS STAYING
ELEVATED IN THE 20 TO 25 KT RANGE...WITH A FEW PERIODS OF 30 KTS.
ANOTHER LOW IS EXPECTED TO LIFT FROM THE LOWER MISSISSIPPI VALLEY
INTO THE EASTERN LAKES REGION EARLY NEXT WEEK.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020 UNTIL 6 PM
WEDNESDAY.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM WEDNESDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...3 AM THURSDAY TO 3 PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...11 PM
WEDNESDAY TO 3 PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ744-LMZ745...1 AM THURSDAY TO 4 AM
FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1000 AM CST Wed Dec 4 2013
.DISCUSSION...
ISSUED 1000 AM CST Wed Dec 4 2013
Dense fog starting to slowly lift in some areas. Have lopped off a
few counties from the advisory from Springfield westward where
visibility has been more persistently around a mile or so. Seeing
some variable visibilities from Peoria northwest and also over the
southeast counties, and will evaluate over the next hour whether
to drop the advisory there too or let it ride until its natural
conclusion at noon. HRRR model showing a more persistent lifting
of the dense fog over the next couple hours, although the RAP
lingers it east of I-57 into early afternoon.
Latest surface map shows low pressure over central Missouri, with
a secondary low over south central Iowa which should become the
primary low late today. Should start seeing the cold front moving
into the Illinois River valley toward 5-6 pm and across most of
the CWA by 10 pm.
Geelhart
&&
.AVIATION...
ISSUED 515 AM CST Wed Dec 4 2013
High resolution models continue to suggest areas that have seen a
temporary break in the low vsbys and cigs will see deteriorating
conditions once again around or just after daybreak this morning.
Model trends off the HRRR and HopWRF continue to suggest VLIFR
vsbys/cigs expanding north into all of our TAF sites after 12z.
Confidence not that great with this scenario...although we have
seen a gradual lowering of cigs and vsbys in areas that saw some
improvement earlier this morning. Poorest conditions look to be
from 12 or 13z thru 18z...and then LIFR/IFR cigs most areas this
afternoon just ahead of a cold front which is currently tracking
across Iowa. Looks as if the cold front should start to push into
our western taf sites by 00z and be east of the CMI area by
05 or 06z tonight. Surface winds ahead of the front will remain
out of the southeast to south at 10 to 15 kts today...and then
shift into west and then northwest after FROPA later this evening.
Smith
&&
.PREV DISCUSSION...
ISSUED 311 AM CST Wed Dec 4 2013
Main forecast concern continues to be potential for accumulating
snow and ice across parts of central Illinois late Thursday into
Friday.
SHORT TERM...Today through Friday
Widespread fog once again blankets the area early this morning.
Moist low-level airmass remains in place, with 08z/2am surface
dewpoints well into the 40s. This ample moisture combined with
light winds will allow visibilities to continue to drop over the
next couple of hours. NAM/GFS forecast soundings and latest HRRR
visby forecast all point to widespread dense fog through much of
the morning. Will therefore be issuing a Dense Fog Advisory for
the entire KILX CWA through midday. Fog will gradually dissipate
by early afternoon, although visibilities will continue to be
somewhat limited until cold front pushes through late this
afternoon into the evening. Despite FROPA later today, shallow
moisture below 5000ft will limit precip potential. Will therefore
only mention isolated showers today into this evening. High
temperatures will be quite a bit warmer than they were yesterday,
but will be tempered by the fog/clouds to some extent. Will go
near or slightly above MAV guidance numbers, but not as high as
the warmer MET. Resulting highs will mainly be in the upper 50s
and lower 60s.
Once front passes, much colder air will arrive tonight into
Thursday. Overnight lows will drop into the upper 20s and lower
30s across much of the area, but will remain in the upper 30s
further east near the Indiana border. High temperatures on
Thursday will not rise much from the early morning lows, with
readings ranging from the upper 20s along/west of the Illinois
River to around 40 degrees along the Wabash River.
Models are in good agreement with the development of wintry precip
across parts of central and southeast Illinois late Thursday into
Friday, with a few minor differences still remaining. NAM has
slowed the onset of precip until early evening, while GFS/ECMWF/GEM
still bring it in during the afternoon. Given drier airmass behind
departing front, think NAM may have the right idea. Will therefore
delay initial precip development until late afternoon, with main
push arriving during the evening. Airmass will be cold enough to
support snow across most of the area: however, warm layer aloft
with max temps of around 4C supports mixed phase precip along and
south of I-70. Late afternoon surface temps in the upper 30s to
around 40 will allow for mainly rain along and south of highway
50. As the evening progresses, deepening cold layer will allow for
a gradual change over to mainly snow across the SE KILX CWA
overnight, although areas along and south of highway 50 may
experience a period of freezing rain as surface temps dip below
32 degrees. Any icing will be minimal, as precip transitions to
snow/sleet after midnight.
Initial wave of precip wanes after midnight, followed by another
wave on Friday. Model differences here focus on how far into the
cold airmass to spread the precip. NAM is most aggressive, while
GFS remains further southeast. Given strength of approaching high
within the cold airmass, think GFS solution is most logical. As a
result, will focus highest POPs for snow across the E/SE CWA. Once
the wintry precip ends Friday afternoon, total snowfall
accumulations of 3 to 5 inches will be likely along and south of
I-70. Amounts will steadily decrease further northwest, with up
to 1 inch possible along a Jacksonville to Danville line. Further
north, only a few flurries are expected along and north of a
Rushville to Bloomington-Normal line.
LONG TERM...Saturday through Tuesday
Cold weather will prevail throughout the extended, with only a brief
moderation in temps expected on Sunday. Models continue to show
another short-wave trough digging southward into the western
CONUS this weekend, resulting in downstream ridging over the
southeast states. As flow becomes more southwesterly aloft,
frontal boundary along the Gulf Coast will get pushed back
northward Sunday into Monday. It appears deepest moisture and
highest precip chances will remain southeast of Illinois across
the Tennessee and Ohio River Valleys, although the GFS is slightly
more aggressive in bringing precip further northwest into the cold
air than the ECMWF. At this point, will trend toward the ECMWF and
will only feature low chance POPs for snow Sunday and Sunday night
with minimal accumulations. After that, another very cold airmass
will drop into the Midwest by early next week, resulting in high
temps in the teens by Tuesday.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY until noon CST today for ILZ027>031-036>038-
041>046-052>057-061>063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
551 AM CST WED DEC 4 2013
.DISCUSSION...
406 AM CST
FORECAST CONCERNS THIS MORNING FOCUS ON DENSE FOG TRENDS THIS
MORNING...AND TRENDS INTO THIS AFTERNOON WITH MILD TEMPS UNTIL COLD
FROPA LATE AFTERNOON/EVENING. COLDER AIR COMES IN TWO PUSHES...
FIRST BEHIND THE FRONT TONIGHT AND THEN A SECOND PUSH FRIDAY
NIGHT-SATURDAY AS ARCTIC HIGH BUILDS MORE SOLIDLY EAST ACROSS THE
GREAT LAKES REGION. COUPLE OF CHANCES OF SOME LIGHT ACCUMULATING
SNOW IN THE COMING DAYS...INITIALLY ACROSS FAR SOUTHEAST CWA LATE
THURSDAY INTO FRIDAY...AND AND ACROSS THE CWA SUNDAY-SUNDAY NIGHT.
EVEN COLDER PUSH OF ARCTIC AIR APPEARS HEADED FOR THE AREA BY THE
MIDDLE OF NEXT WEEK.
VERY MILD AND MOIST AIR MASS IN PLACE ACROSS THE REGION EARLY THIS
MORNING...WITH BOTH SFC TEMPS AND DEW POINTS IN THE 40S WITH VERY
SMALL DEPRESSIONS. DENSE FOG WITH VISIBILITY LESS THAN 1/2SM
CONTINUES ACROSS THE FAR NORTHERN IL COUNTIES ROUGHLY NORTH OF A
STERLING TO DEKALB AND WAUKEGAN LINE AS OF 330 AM CST...WITH A
SMALLER AREA OF DENSE FOG OVER EAST CENTRAL IL. HIGH-RES GUIDANCE
INCLUDING HOPWRF AND NARRE TIME-LAGGED ENSEMBLES INDICATE THERE MAY
BE SOME IMPROVEMENT IN VISIBILITY ACROSS THE NORTHERN COUNTIES THIS
MORNING...WHILE SOME ENSEMBLE MEMBERS EXPAND DENSE FOG ACROSS
CENTRAL IL PRIOR TO ABOUT 15Z AND THEN DECREASE COVERAGE. OBS AT
PNT-IKK AND RZL HAVE NOT SHOWN A SIGNIFICANT DOWNWARD TREND AT THIS
TIME. WILL LEAVE ONGOING DENSE FOG ADVISORY ACROSS THE NORTH AS
IS...AND WILL CONTINUE TO MONITOR TRENDS ACROSS THE SOUTH FOR THE
POSSIBILITY OF NEEDING A HEADLINE THERE. WHILE VISIBILITY MAY
IMPROVE SOMEWHAT...AREAS OF FOG WILL LIKELY STICK AROUND INTO THE
AFTERNOON BEFORE AN INCREASE IN SCATTERED SHOWER COVERAGE...WARMER
DAYTIME TEMPERATURES AND THE EVENTUAL COLD FRONTAL PASSAGE CLEAR
THINGS OUT THIS EVENING.
WHILE COLDER MORE TYPICAL EARLY WINTER WEATHER WILL SPREAD INTO THE
AREA TONIGHT/THURSDAY...THE DEPARTING COLD FRONT WILL SLOW AS IT
BECOMES PARALLEL WITH THE MID/UPPER FLOW AND MOVES INTO THE EASTERN
LAKES AND OHIO VALLEY OVER THE NEXT 24-36 HOURS. THIS WILL LIMIT THE
EXTENT OF THE COLD AIR INTRUSION BEHIND THE FRONT...AND WILL LEAVE
THE ELEVATED FRONTAL ZONE ACROSS CENTRAL IL AND NORTHERN INDIANA
INTO FRIDAY. GUIDANCE REMAINS FAIRLY SIMILAR IN BRINGING TWO
SEPARATE DISTURBANCES ALONG THIS BAROCLINIC ZONE WITH THE FIRST LATE
THURSDAY/THURSDAY NIGHT...AND THE OTHER DURING THE DAY ON FRIDAY.
REASONABLY SIMILAR QPF OUTPUT FROM THE VARIOUS MODELS OF THE
AVAILABLE GUIDANCE INDICATE THE POTENTIAL FOR GENERALLY LESS THAN AN
INCH OF SNOW ACROSS THE FAR SOUTHEAST TIER OF COUNTIES OF THE CWA
BEFORE THE SECOND SHORT WAVE DEPARTS LATE FRIDAY...WITH FLURRIES
PERHAPS AS FAR NORTH AS A PONTIAC-WHITING LINE. AFTER THIS SECOND
SLIGHTLY MORE AMPLIFIED WAVE DEPARTS...ARCTIC HIGH PRESSURE BUILDS
MORE ROBUSTLY EAST ACROSS MINNESOTA AND WISCONSIN FRIDAY NIGHT AND
SETS THE STAGE FOR CHILLY TEMPS IN THE SINGLE DIGITS AWAY FROM THE
CITY FRIDAY NIGHT...AND ONLY IN THE TEENS TO LOW 20S SATURDAY.
LONGER RANGE GUIDANCE ALSO REMAINS IN DECENT AGREEMENT IN BRINGING
ANOTHER SHORT WAVE INTO THE REGION SUNDAY-SUNDAY NIGHT...WITH SOME
SPREAD IN THE MODEL SOLUTIONS LOOKING A LITTLE MORE IN AGREEMENT
WITH THE NEW 00Z ECMWF SIMILAR TO THE GFS IN BRINGING LOW PRESSURE
THROUGH THE OHIO VALLEY DURING THAT TIME. LIGHT SNOW LOOKS TO COVER
MOST/ALL OF THE CWA WITH THIS SYSTEM...AND HAVE BUMPED POPS TO
LIKELY IN MOST AREAS.
ANOTHER SURGE OF ARCTIC AIR THEN LOOKS TO SPREAD INTO THE AREA
BEHIND THIS SYSTEM MONDAY-TUESDAY. BOTH ECMWF/GFS MOS GUIDANCE
SHOWING LOWS IN THE SINGLE DIGITS BY TUESDAY MORNING...WITH HIGHS
ONLY AROUND 12-15 TUESDAY. THIS IS IMPRESSIVE GIVEN STRONG CLIMO
WEIGHTING IN THE MOS BY DAY 7...SOME 22-25 DEGREES BELOW NORMAL FOR
HIGHS FOR EARLY DECEMBER. BRRR.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* VARIABLE CIGS THIS MORNING...BECOMING PREVAILING IFR MID MORNING
THROUGH LATE AFTERNOON...WITH SLIGHT IMPROVEMENT POSSIBLE
THEREAFTER.
* VISIBILITY TRENDS...WITH POTENTIAL FOR FOG TO SPREAD NORTH INTO
THE TERMINALS.
BMD
//DISCUSSION...UPDATED 12Z...
THIS MORNING...A WARM FRONT LIES JUST NORTH OF THE TERMINALS WITH
SOUTHEAST FLOW AND IFR CONDITIONS IN PLACE ACROSS NORTHERN ILLINOIS
AND NORTHWEST INDIANA. WILL DISCUSS EACH FORECAST ELEMENT
INDIVIDUALLY...
CEILINGS...AS MENTIONED MOST OF THE REGION IS UNDER IFR CIGS THIS
MORNING...THOUGH THERE IS A HOLE IN THE LOWER CIGS THAT STRETCHES
FROM SW MICHIGAN INTO THE SOUTH CHICAGO METRO. GYY HAS MAINTAINED
VFR LEVEL CIGS FOR THE PAST SEVERAL HOURS...AND MDW HAS BEEN IN AND
OUT OF THE IFR CIGS. NAM/HRRR GUIDANCE TO SOME DEGREE HINTING AT
THIS HOLE...WHICH COULD BRIEFLY MOVE OVER ORD THIS MORNING. BOTH
MODELS DO SHOW THE HOLE FILLING IN THOUGH LATE THIS MORNING...SO ANY
TEMPO HIGHER CIGS WILL BE SHORT LIVED THIS MORNING. A SECONDARY WARM
FRONTAL LIKE FEATURE WILL LIFT ACROSS THE AREA THIS AFTERNOON...WITH
WINDS VEERING TO THE S OR SSW. MODELS INDICATE SOME IMPROVEMENT IN
CIGS POSSIBLE AFTER IT PASSES NORTH OF THE TERMINALS...THOUGH THE
DEGREE OF IMPROVEMENT IS UNCERTAIN. IT IS POSSIBLE WE MAY LIFT TO
MVFR AT THIS POINT...BUT WILL ERR ON THE SIDE OF LOWER CIGS FOR NOW
WHICH FITS WELL WITH LAV/MET GUIDANCE. BETTER CHANCE TO LIFT TO MVFR
WILL BE LATER IN THE EVENING AS A COLD FRONT SWEEPS ACROSS THE AREA.
EXPECT THE CIGS TO GRADUALLY RISE OVERNIGHT AS THE COLD AIR ERODES
THE CLOUD BASES.
VISIBILITY...VSBY RANGES FROM NEAR ZERO TO AROUND 4-5SM. DENSEST FOG
IS GENERALLY ALONG AND NEAR THE WARM FRONT AND THIS AREA SHOULD STAY
NORTH OF THE CHICAGO TERMINALS...THOUGH WILL CONTINUE TO IMPACT RFD
THROUGH THE MORNING. MODEL GUIDANCE IS ALL OVER THE PLACE WITH
RESPECT TO VSBY TRENDS TODAY. SEVERAL MODELS HINT THAT AS THE
SECONDARY BOUNDARY SOUTH OF THE AREA LIFTS NORTH...LOWER VSBY WILL
ALSO SPREAD NORTH INTO THE CHICAGO METRO. THERE IS ALREADY DENSE FOG
ACROSS PORTIONS OF EAST CENTRAL ILLINOIS...AND WILL HAVE TO MONITOR
THIS AREA CLOSELY AS IT MAY SPREAD NORTH OVER THE TERMINALS...BUT
FOR NOW GIVEN THE LOW CONFIDENCE...WILL STICK CLOSE TO MAV/LAV
TRENDS WHICH HOLD VSBY PRIMARILY MVFR FOR THE CHICAGO TERMINALS
TODAY. ANY PRECIP THAT DEVELOPS THIS AFTERNOON MAY ALSO CAUSE THE
VSBY TO DROP TO IFR.
WINDS...PRIMARILY SOUTHEASTERLY WINDS 6-10KTS ARE EXPECTED THIS
MORNING BEHIND THE FRONT NEAR THE STATE LINE THIS MORNING. WINDS
WILL EVENTUALLY VEER TO THE SOUTH/SSW AS THE SECOND BOUNDARY LIFTS
ACROSS THE AREA MID TO LATE THIS AFTERNOON. LATE THIS EVENING A COLD
FRONT WILL SWEEP ACROSS THE AREA WITH WINDS TURNING WESTERLY...AND
INCREASING WITH GUSTS INTO THE HIGH TEENS EXPECTED OVERNIGHT.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN CIG TRENDS THROUGH THE PERIOD.
* LOW CONFIDENCE IN VSBY TRENDS THIS MORNING THROUGH THIS AFTERNOON.
* MEDIUM CONFIDENCE IN WINDS.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT THROUGH SATURDAY...VFR.
SUNDAY...CHC SNOW...WITH SNOW LIKELY SUNDAY NIGHT.
MONDAY...SLT CHC SNOW. MVFR POSSIBLE.
TUESDAY...PRIMARILY VFR.
BMD
&&
.MARINE...
239 AM CST
MODELS ARE FINALLY SYNCED UP ON DEEPENING LOW PRESSURE WHICH IS
EXPECTED TO LIFT ACROSS WISCONSIN LATE THIS AFTERNOON...AND ACROSS
LATE SUPERIOR TONIGHT. MODERATE EASTERLY FLOW AROUND 30 KTS IS
EXPECTED NORTH OF A WARM FRONT STRADDLING THE MID SECTION OF THE
LAKE THIS MORNING...WITH STABLE SOUTHEASTERLY FLOW ACROSS THE SOUTH
OF THE FRONT. MID/UPPER 40 DEWPOINTS ADVECTING OVER THE LOW/MID 40
DEGREE WATER TEMPERATURES IS EXPECTED TO RESULT IN WIDESPREAD DENSE
FOG. A DENSE FOG ADVISORY IS IN EFFECT ACROSS THE SOUTH HALF OF THE
LAKE...BUT MAY NEED TO BE EXTENDED NORTH AS THE FRONT LIFTS ACROSS
THE REMAINDER OF THE LAKE. OVERNIGHT A COLD FRONT WILL SWEEP ACROSS
THE LAKE WITH WINDS TURNING WESTERLY BEHIND. STRONG COLD ADVECTION
WILL HELP TO MIX DOWN GALES...PRIMARILY ACROSS THE NORTH END OF THE
LAKE WHERE THE GRADIENT IS TIGHTEST...THOUGH APPEARS FOR NOW TO BE
LOW END GALE EVENT. A GALE WATCH REMAINS IN EFFECT FOR THE NORTH
PORTIONS OF THE LAKE. A STRONG HIGH WILL SETTLE ACROSS THE NORTHERN
PLAINS FRIDAY THOUGH LATE SATURDAY RESULTING IN WINDS STAYING
ELEVATED IN THE 20 TO 25 KT RANGE...WITH A FEW PERIODS OF 30 KTS.
ANOTHER LOW IS EXPECTED TO LIFT FROM THE LOWER MISSISSIPPI VALLEY
INTO THE EASTERN LAKES REGION EARLY NEXT WEEK.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012 UNTIL 10 AM WEDNESDAY.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-
LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 PM WEDNESDAY.
GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...3 AM THURSDAY TO 3 PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...11 PM
WEDNESDAY TO 3 PM THURSDAY.
SMALL CRAFT ADVISORY...LMZ744-LMZ745...1 AM THURSDAY TO 4 AM
FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
527 AM CST Wed Dec 4 2013
.DISCUSSION...
ISSUED 311 AM CST Wed Dec 4 2013
Main forecast concern continues to be potential for accumulating
snow and ice across parts of central Illinois late Thursday into
Friday.
SHORT TERM...Today through Friday
Widespread fog once again blankets the area early this morning.
Moist low-level airmass remains in place, with 08z/2am surface
dewpoints well into the 40s. This ample moisture combined with
light winds will allow visibilities to continue to drop over the
next couple of hours. NAM/GFS forecast soundings and latest HRRR
visby forecast all point to widespread dense fog through much of
the morning. Will therefore be issuing a Dense Fog Advisory for
the entire KILX CWA through midday. Fog will gradually dissipate
by early afternoon, although visibilities will continue to be
somewhat limited until cold front pushes through late this
afternoon into the evening. Despite FROPA later today, shallow
moisture below 5000ft will limit precip potential. Will therefore
only mention isolated showers today into this evening. High
temperatures will be quite a bit warmer than they were yesterday,
but will be tempered by the fog/clouds to some extent. Will go
near or slightly above MAV guidance numbers, but not as high as
the warmer MET. Resulting highs will mainly be in the upper 50s
and lower 60s.
Once front passes, much colder air will arrive tonight into
Thursday. Overnight lows will drop into the upper 20s and lower
30s across much of the area, but will remain in the upper 30s
further east near the Indiana border. High temperatures on
Thursday will not rise much from the early morning lows, with
readings ranging from the upper 20s along/west of the Illinois
River to around 40 degrees along the Wabash River.
Models are in good agreement with the development of wintry precip
across parts of central and southeast Illinois late Thursday into
Friday, with a few minor differences still remaining. NAM has
slowed the onset of precip until early evening, while GFS/ECMWF/GEM
still bring it in during the afternoon. Given drier airmass behind
departing front, think NAM may have the right idea. Will therefore
delay initial precip development until late afternoon, with main
push arriving during the evening. Airmass will be cold enough to
support snow across most of the area: however, warm layer aloft
with max temps of around 4C supports mixed phase precip along and
south of I-70. Late afternoon surface temps in the upper 30s to
around 40 will allow for mainly rain along and south of highway
50. As the evening progresses, deepening cold layer will allow for
a gradual change over to mainly snow across the SE KILX CWA
overnight, although areas along and south of highway 50 may
experience a period of freezing rain as surface temps dip below
32 degrees. Any icing will be minimal, as precip transitions to
snow/sleet after midnight.
Initial wave of precip wanes after midnight, followed by another
wave on Friday. Model differences here focus on how far into the
cold airmass to spread the precip. NAM is most aggressive, while
GFS remains further southeast. Given strength of approaching high
within the cold airmass, think GFS solution is most logical. As a
result, will focus highest POPs for snow across the E/SE CWA. Once
the wintry precip ends Friday afternoon, total snowfall
accumulations of 3 to 5 inches will be likely along and south of
I-70. Amounts will steadily decrease further northwest, with up
to 1 inch possible along a Jacksonville to Danville line. Further
north, only a few flurries are expected along and north of a
Rushville to Bloomington-Normal line.
LONG TERM...Saturday through Tuesday
Cold weather will prevail throughout the extended, with only a brief
moderation in temps expected on Sunday. Models continue to show
another short-wave trough digging southward into the western
CONUS this weekend, resulting in downstream ridging over the
southeast states. As flow becomes more southwesterly aloft,
frontal boundary along the Gulf Coast will get pushed back
northward Sunday into Monday. It appears deepest moisture and
highest precip chances will remain southeast of Illinois across
the Tennessee and Ohio River Valleys, although the GFS is slightly
more aggressive in bringing precip further northwest into the cold
air than the ECMWF. At this point, will trend toward the ECMWF and
will only feature low chance POPs for snow Sunday and Sunday night
with minimal accumulations. After that, another very cold airmass
will drop into the Midwest by early next week, resulting in high
temps in the teens by Tuesday.
&&
.AVIATION...
ISSUED 515 AM CST Wed Dec 4 2013
High resolution models continue to suggest areas that have seen a
temporary break in the low vsbys and cigs will see deteriorating
conditions once again around or just after daybreak this morning.
Model trends off the HRRR and HopWRF continue to suggest VLIFR
vsbys/cigs expanding north into all of our TAF sites after 12z.
Confidence not that great with this scenario...although we have
seen a gradual lowering of cigs and vsbys in areas that saw some
improvement earlier this morning. Poorest conditions look to be
from 12 or 13z thru 18z...and then LIFR/IFR cigs most areas this
afternoon just ahead of a cold front which is currently tracking
across Iowa. Looks as if the cold front should start to push into
our western taf sites by 00z and be east of the CMI area by
05 or 06z tonight. Surface winds ahead of the front will remain
out of the southeast to south at 10 to 15 kts today...and then
shift into west and then northwest after FROPA later this evening.
Smith
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY until Noon CST today FOR ILZ027>031-036>038-
040>057-061>063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
951 PM EST THU DEC 5 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 1258 PM EST THU DEC 5 2013
AN ACTIVE WEATHER PATTERN IS EXPECTED THE NEXT 24 HOURS AS WINTRY
WEATHER RETURNS TO CENTRAL INDIANA. A COLD FRONT HAS PUSHED
SOUTHEAST OF CENTRAL INDIANA...ALLOWING MUCH COLDER AIR TO PUSH IN
TO THE AREA. A FLOW OF MOIST AIR ALOFT ALONG WITH SEVERAL UPPER
LEVEL WEATHER DISTURBANCES ARE EXPECTED TO PUSH IN TO
CENTRAL INDIANA TONIGHT AND AGAIN ON FRIDAY. THIS WILL RESULT IN
ACCUMULATING SNOW TONIGHT AND FRIDAY FOR MOST OF CENTRAL
INDIANA...AND THE FIRST REAL BIG SNOW OF THE SEASON.
HIGH PRESSURE IS EXPECTED TO BUILD ACROSS THE AREA FRIDAY
NIGHT...ENDING THE SNOW. HOWEVER VERY COLD...ARCTIC AIR WILL ARRIVE
IN INDIANA...WITH TEMPERATURES WELL BELOW NORMAL THOUGH THE WEEKEND.
ANOTHER PASSING STORM SYSTEM MAY BRING SOME LIGHT SNOW OR FREEZING
PRECIPITATION TO AREA ON SUNDAY THROUGH MONDAY. YET ANOTHER SHOT
OF ARCTIC AIR IS THEN EXPECTED TO ARRIVE ON FOR THE MIDDLE OF NEXT
WEEK AND HIGH TEMPERATURES WILL ONLY BE IN THE TEENS.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 951 PM EST THU DEC 5 2013
NAM12 AND RUC13 MODEL SOUNDINGS AND OBSERVATIONAL TRENDS SUGGEST
PRECIPITATION TYPE WILL MAINLY BE SNOW THE REST OF THE NIGHT WITH
THE EXCEPTION OF THE FAR SOUTH...WHERE SOME SLEET IS POSSIBLE
THROUGH MIDNIGHT. LOOKING AT RAPID REFRESH REFLECTIVITY PROGS AND
WITH SHARP DEEP MOISTURE GRADIENT...SOME CONCERN NORTHWEST COUNTIES
WILL NOT SEE MUCH ACCUMULATION TONIGHT...BUT HATE TO PULL POPS AND
ACCUMULATION TOO SOON...SO FOR NOW WILL STICK WITH IT. UPDATED
GRIDDS...HAZARDOUS WEATHER OUTLOOK AND WEATHER STORY WITH NEW WEB
STORM BRIEFING TO COME.
PREVIOUS DISCUSSION FOLLOWS...
RADAR THIS AFTERNOON SHOWS A SURGE OF MOISTURE OVER SOUTHERN
ILLINOIS STREAMING NORTHEAST TOWARD CENTRAL INDIANA. SURFACE
ANALYSIS EARLY THIS AFTERNOON SHOWS COLD HIGH PRESSURE IN PLACE
ACROSS THE CENTRAL PLAINS AND A COLD FRONT EAST OF INDIANA...OVER
CENTRAL OHIO...EASTERN KENTUCKY AND CENTRAL TENNESSEE. COLD WEST
TO NORTHWEST SURFACE FLOW WAS IN PLACE ACROSS CENTRAL INDIANA.
SURFACE TEMPS WERE FALLING THIS AFTERNOON ACROSS THE NORTHWEST
PARTS OF THE STATE AND BARELY RISING ACROSS SOUTH. THE WATER VAPOR
IMAGERY IS IMPORTANT TODAY. IT SHOWS A PLUME OF MOISTURE STREAMING
ACROSS MEXICO INTO THE AMERICAN SOUTHWEST AND THEN NORTHEAST INTO
THE GREAT LAKES AND OHIO VALLEY. THIS STREAM OF MOISTURE WILL BE
OUR SOURCE FOR PRECIP OVER THE NEXT 24-36 HOURS.
FORECAST SOUNDINGS ACROSS THE AREA LEAN TOWARD A FREEZING RAIN
PRECIP TYPE LATE THIS AFTERNOON AND THIS EVENING ACROSS SOUTHERN
PARTS OF CENTRAL INDIANA. PRECIPITABLE WATER VALUES AROUND 0.8
INDICATE PLENTY OF MOISTURE AVAILABLE FOR THIS SYSTEM. COLDER AIR
IS EXPECTED TO ARRIVE ACROSS THE ENTIRE FORECAST AREA AFTER 06Z AS
ALL FORECAST SOUNDINGS FALL BELOW FREEZING...CHANGING THE PRECIP
TYPE TO ALL SNOW REGION WIDE.
THUS HAVE TRENDED FORECASTS TOWARD 100 POPS...WITH BEST CHANCES
FOR FREEZING PRECIP ACROSS SOUTHERN PARTS OF THE FORECAST AREA
THIS EVENING. ALSO GIVEN THE EXPECTED PATH OF THE BAND OF
MOISTURE...SOUTHERN INDIANA IS IN THE MOST FAVORABLE POSITION FOR
HEAVIER SNOW AMOUNTS. AS FOR TEMPS...GIVEN THE COLD AIR ADVECTION
BUT EXPECTED PRECIPITATION...HAVE TRENDED LOWS AT OR ABOVE MAVMOS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
ISSUED AT 1258 PM EST THU DEC 5 2013
SNOW IS EXPECTED ON FRIDAY. FORECAST SOUNDINGS AND TIME HEIGHT
SECTIONS CONTINUE TO SUGGEST A SATURATED COLUMN THROUGH THE DAY
WITH SOUNDINGS ENTIRELY BELOW FREEZING. FLOW ALOFT CONTINUES TO
SUGGEST THE MOIST SOUTHERN JET OF MOISTURE STREAMING IN TO THE
OHIO VALLEY. EMBEDDED SHORT WAVE ARE EXPECTED TO PROVIDE MORE
FORCING FOR ONGOING SNOW. TIME HEIGHT SECTIONS SHOW ANOTHER ROUND
OF GOOD VV DURING THE AFTERNOON HOURS. PRECIPITABLE WATER VIA
FORECAST SOUNDINGS SHOW A CONTINUOUS STREAM OF MOISTURE ACROSS THE
AREA WITH VALUES AROUND 0.60-0.80 FROM 12Z THROUGH 18Z AND AFTER
BEFORE TRAILING OFF AFTER 00Z SAT. THUS PLENTY OF MOISTURE APPEARS
AVAILABLE.
FRONTOGENESIS FORCING APPEARS VERY FAVORABLE FOR THIS
EVENT...AGAIN SHOWING A PERIOD STRONG FORCING MID DAY FRIDAY. THUS
WITH HIGH MOISTURE AND VERY GOOD FORCING EXPECT BANDS OF SNOW
ACROSS THE AREA ON FRIDAY. AGAIN...HEAVIEST AMOUNTS WILL BE ACROSS
THE SOUTHERN PARTS OF FORECAST AREA...WITH LIGHTER AMOUNTS NORTHWEST.
WITH ONGOING PRECIP EXPECTED ON FRIDAY HAVE TRENDED TEMPS COOLER
THAN MAV...STEADY IN THE UPPER 20S.
ON FRIDAY NIGHT...DEEP MOISTURE IS LOST IN THE FORECAST SOUNDINGS
AS BEST FORCING IS LOST AND THE SOUTHERN STREAM SHIFTS EAST. HIGH
PRESSURE OVER THE CENTRAL PLAINS CONTINUES TO BUILD ACROSS THE
REGION A COLD SURFACE RIDGE BUILDS ACROSS CENTRAL ILLINOIS AND
CENTRAL INDIANA. THUS WILL TREND TOWARD A BECOMING PARTLY CLOUDY
SKY. A FEW LINGERING SNOW SHOWERS OR FLURRIES WILL BE POSSIBLE
ACROSS THE EAST AS FRIDAY/S SYSTEM DEPARTS.
HIGH PRESSURE WILL PROVIDE COLD BUT DRY WEATHER FOR SATURDAY.
FORECAST SOUNDINGS REMAIN QUITE DRY. THUS WILL TREND TOWARD A
PARTLY CLOUDY SKY. AS FOR TEMPS DURING THIS PERIOD...GIVEN THE
EXPECTED FRESH SNOW AND COLD AIR IN PLACE WILL TREND HIGHS AND
LOWS COOLER THAN MAVMOS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 252 PM EST THU DEC 5 2013
MAIN ISSUE IN THE LONG TERM IS ANOTHER WINTER SYSTEM POSSIBLY
IMPACTING THE AREA EARLY SUNDAY INTO SUNDAY NIGHT. MODELS APPEAR
THEY MAY BE TRENDING SLIGHTLY COOLER MAINLY DURING THE DAY ON
SUNDAY. PRECIP MAY SNEAK INTO THE SOUTHERN FORECAST AREA AROUND
DAYBREAK SUNDAY IN THE FORM OF SNOW...WITH LIGHT SNOW POTENTIALLY
ACROSS MUCH OF THE AREA SUNDAY MORNING. PRECIP MAY TRANSITION TO A
MIX OF SLEET AND SNOW WITH SOME FREEZING RAIN POSSIBLE ACROSS THE
SOUTHWEST SUNDAY AFTERNOON. THIS MIX POTENTIAL WILL EXPAND A BIT
FURTHER NORTHWEST SUNDAY EVENING BEFORE COLD AIR AGAIN OVERTAKES THE
AREA AND MOST PRECIP LATE SUNDAY NIGHT CHANGES BACK TO SNOW...WITH
THE EXCEPTION OF A LIGHT MIX POSSIBLE IN THE EAST.
AMOUNTS WITH THIS SYSTEM...WHILE STILL QUITE UNCERTAIN BEING SO FAR
OUT...APPEAR VERY LIGHT ACROSS MOST OF THE FORECAST AREA. ACROSS THE
SOUTHEASTERN HALF OF THE AREA...FROM VINCENNES TO INDIANAPOLIS AND
MUNCIE SOUTHEASTWARD...1-3 INCHES OF SNOW/SLEET APPEAR POSSIBLE WITH
POTENTIAL FOR A FEW HUNDREDTHS OF FREEZING RAIN. SNOW/SLEET
ACCUMULATIONS OF UP TO 4 INCHES APPEAR POSSIBLE ACROSS THE FAR
SOUTHEASTERN FORECAST AREA...IN THE NORTH VERNON AREA.
ONCE THIS SYSTEM EXITS...DRY WEATHER WILL DOMINATE THE REMAINDER OF
THE FORECAST PERIOD...AND TEMPS WILL TURN SHARPLY COLDER. HIGHS MAY
NOT GET OUT OF THE TEENS AT TIMES NEXT WEEK. ALLBLEND HANDLED THE
OUTER PERIODS WELL AND FEW CHANGES WERE REQUIRED.
&&
.AVIATION /DISCUSSION FOR 060300Z TAF ISSUANCE/...
ISSUED AT 935 PM EST THU DEC 5 2013
UPDATED TO DROP CURRENT CONDITIONS AND NEXT FEW HOURS AT KHUF AND
KIND WITH IFR SNOW BAND IN PLACE. KEPT MIX GOING AT KBMG AS IT WILL
LIKELY CONTINUE TO BOUNCE AROUND WITH PRECIP TYPE FOR THE NEXT FEW
HOURS. ALTHOUGH MVFR IS OCCURRING THERE NOW EXPECT IT TO BE BRIEF
BEFORE DROPPING BACK TO IFR SO LEFT IFR PREVAILING.
PREVIOUS DISCUSSION FOLLOWS...
DETERIORATING FLYING CONDITIONS ARE EXPECTED AT THE SITES AS A
STRONG WINTER STORM IS IN PLACE ACROSS CENTRAL INDIANA FOR THE
NEXT 24 HOURS. KLAF IS NORTH ENOUGH TO MISS MOST OF THE EFFECTS
AND WILL KEEP VFR THERE THROUGH THE NIGHT BUT MVFR TO IFR FRIDAY
LATE MORNING/AFTERNOON AS SNOW FINALLY GETS GOING THERE THEN. KHUF
AND KIND APPEAR TO BE VERY CLOSE TO A LINE OF SNOW/SLEET/FREEZING
RAIN MIX VERSUS NO PRECIP AND RADAR SHOWS THIS PRECIP/NO PRECIP
LINE COULD CONTINUE IN A SIMILAR SPOT FOR THE NEXT COUPLE OF
HOURS BEFORE INCHING NORTH. FORECAST SOUNDINGS THOUGH SHOW PRECIP
SHOULD BE ALL SNOW AT THESE SITES BY 0-1Z. THESE SOUNDINGS ALSO
INDICATE HEAVIEST SNOW COULD OCCUR IN A 6-8Z OR SO TIME WINDOW SO
INCLUDED A TEMPO GROUP THEN WITH 1/2SM AND IFR CEILINGS. UNTIL
THEN EXPECT MVFR. FRIDAY GUIDANCE AND SOUNDINGS SHOW SNOW THROUGH
THE DAY WITH DROPPING CEILINGS. AT KBMG FREEZING RAIN IS OCCURRING
AND COULD CONTINUE FOR SOME TIME WITH SLEET MIXING IN OFF AND ON
UNTIL AROUND 6-7Z ACCORDING TO FORECAST SOUNDINGS BEFORE CHANGING
OVER TO SNOW. LOW END MVFR TO HIGH END IFR CEILINGS MOST OF THE
NIGHT THERE WITH LOWERING HAPPENING LATE FRIDAY MORNING AND
HEAVIER SNOW ARRIVING. THE SYSTEM SHOULD BE ON IT/S WAY OUT BY THE
END OF THE TAF PERIOD AROUND 0Z SATURDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 10 PM THIS EVENING TO MIDNIGHT EST
FRIDAY NIGHT FOR INZ037-039>042-044>049-051>057-060>065-067>072.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST FRIDAY NIGHT FOR
INZ021-028>031-035-036-038-043.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA/MK
SHORT TERM...PUMA
LONG TERM....NIELD
AVIATION...CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1150 PM CST TUE DEC 3 2013
.UPDATE...
ISSUED AT 941 PM CST TUE DEC 3 2013
WARM FRONT NEAR QUAD CITIES ATTIM...WITH WIDESPREAD DENSE FOG
CONTINUING TO BE FOUND NORTH OF THE BOUNDARY. THE WARM
FRONT HAS NOT MOVED MUCH THIS EVENING WITH AS AXIS OF PRESSURE
RISES PASSING THROUGH. GIVEN THIS ALONG WITH LIGHT WINDS AND
ABUNDANT HAVE BEEN GETTING REPORTS OF PATCHY TO AREAS OF DENSE
FOG IN SOUTHEAST CWA SOUTH OF THE WARM FRONT. WITH THINGS
UNCHANGED NEXT FEW HOURS BELIEVE WILL SEE SOME EXPANSION TO THE
DENSE FOG AND HAVE GONE AHEAD AND ADDED REMAINING SOUTHEAST CWA
COUNTIES INTO DENSE FOG ADVISORY. MAY ACTUALLY BE ABLE TO TRIM
THE ADVISORY LATER TONIGHT ESPECIALLY FROM QUAD CITIES E/SE IF THE
WARM FRONT LIFTS NORTH AS MODELS SUGGEST ALLOWING FOR SLIGHT
WARMING AND INCREASE IN WINDS TO ABATE WIDESPREAD DENSE FOG.
&&
.SYNOPSIS...
ISSUED AT 340 PM CST TUE DEC 3 2013
WARM FRONT REACHING FROM DEVELOPING LOW OVER SE CO REACHED E-NE
ACROSS CENTRAL KS TO S CENTRAL IA TO N CENTRAL IL THIS AFTERNOON. AT
21Z...SURFACE ANALYSIS AND VISIBLE SATELLITE IMAGERY INDICATED THE
BOUNDARY BETWEEN FAIRFIELD AND WASHINGTON SE TO BETWEEN GALESBURG AND
MACOMB. FOG WAS WIDESPREAD NORTH OF THIS BOUNDARY AND HAS REMAINED
DENSE THROUGH THE DAY ALONG THE HIGHWAY 20 CORRIDOR. SOUTH OF THE
BOUNDARY...TEMPERATURES WERE IN THE 50S...WHILE 40S WERE FOUND TO
THE NORTH. THE PRIMARY PUSH OF ARCTIC AIR WAS STILL IN THE
PLAINS...WHERE THE MAIN COLD FRONT REACHED FROM NW MN S-SW TO THE
NEB PANHANDLE. BEHIND THIS BOUNDARY...TEMPERATURES WERE IN THE TEENS
AND 20S.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 340 PM CST TUE DEC 3 2013
THE REBOUND OF WIDESPREAD DENSE FOG IS THE INITIAL CHALLENGE...THEN
TRENDS WITH THE PASSAGE OF THE STRONG COLD FRONT THAT IS NOW LIKELY
TO PUSH THROUGH WED AFTERNOON.
THE WARM FRONT WILL TRY TO PUSH NORTH TONIGHT AS THE CO LEE LOW
MIGRATES NORTHEAST ALONG THE BOUNDARY IN KS. THE BROAD LOW LEVEL
CONVERGENT FLOW AND MOISTURE ADVECTION AS DEWPOINTS IN THE 40S OVER
MO AND IL ARE DRAWN NORTH AND NORTHWESTWARD WILL KEEP THE LOW LEVELS
SATURATED. THE HRRR AND SREF FOG PROG TOOLS ARE IN ALIGNMENT WITH
THE CURRENT AREA OF DENSE FOG AND HAVE THIS EXPANDING BACK SOUTH AND
SOUTHWEST OVERNIGHT. THIS IS ALONG THE AREA OF CURRENT CONVERGENCE
FROM S CENTRAL IA NE TO NW IL AND HAVE EXPANDED OUR DENSE FOG
ADVISORY TO COVER THESE AREAS OVERNIGHT. HAVE THIS GOING UNTIL NOON
WEDNESDAY...WHEN THE ENHANCED MIXING AHEAD OF THE FRONT SHOULD BRING
SOME IMPROVEMENT. ACROSS FAR SOUTHEAST IA...FAR NE MO AND WEST
CENTRAL IL ALONG THE I-80 CORRIDOR...FOG WILL LIKELY RETURN...BUT
THERE IS LOW CONFIDENCE AS TO WHETHER IT WILL BECOME DENSE. HAVE
THUS HELD OFF ON AN ADVISORY...BUT WILL NEED TO MONITOR CLOSELY.
OTHERWISE...THE DEVELOPING LIFT AND INCREASING DIFLUENCE IN FLOW
ALOFT WILL SUPPORT ANOTHER ROUND OF LIGHT RAIN...ESPECIALLY TOWARD
MORNING ACROSS THE NORTH AND HAVE MAINTAINED CHANCE POPS.
ELSEWHERE...WILL KEEP A MENTION OF DRIZZLE WITH THE FOG.
WEDNESDAY...LATEST MODELS CONTINUE TO TREND TOWARD THE
EARLIER...SLOWER ECMWF RUNS WITH THE TIMING OF THE FROPA. THE
GFS...NAM...ECMWF...AND GEM OFFER SIMILAR SOLUTIONS WITH THE WAVE OF
LOW PRESSURE MOVING OUT OF THE PLAINS...LIFTING THROUGH THE FORECAST
AREA WEDNESDAY AFTERNOON. THIS USHERS THE PRIMARY COLD FRONT THROUGH
THE AREA BY EARLY EVENING. HAVE TRENDED THE FORECAST TOWARD THE
SLIGHTLY SLOWER ECMWF AND CANADIAN SOLUTIONS...KEEPING THE
PRECIPITATION IN THE FORM OF RAIN WITH A POSSIBLY RAIN/SNOW MIX IN
THE FAR NW LATE. WITH THE PRIMARY WARM SECTOR SWEEPING THROUGH THE
MUCH OF THE WARM SECTOR...WE SHOULD TAP INTO THE AIRMASS OVER
EASTERN MO AND SOUTHERN IL RESULTING IN MORNING OR EARLY AFTERNOON
HIGHS FROM THE LOWER 40S NW TO NEAR 60 IN THE FAR SE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 340 PM CST TUE DEC 3 2013
WEDNESDAY NIGHT THROUGH FRIDAY...TAKING INTO ACCOUNT A TYPE OF
ENSEMBLE FRONTAL MOVEMENT OF THE 12Z MODEL RUNS AND EVEN SLOWING
THAT DOWN SOME AS DEEPENING CYCLONE WRAPS UP SOMEWHERE ACRS
SOUTHWEST INTO CENTRAL WI WED EVENING...IT SHOULD BE PUSHING EAST OF
THE DVN CWA BY 01Z-02Z THU. CONVERGENT FORCING OFF THIS PROCESS MAY
WRING OUT SOME LIGHT RAIN OR DRIZZLE ALONG AND EAST OF THE MS RVR THE
FIRST 1-2 HRS OF THE FCST PERIOD. BUT THE MAIN OVERNIGHT WX STORY
WILL BE THE INCREASING WESTERLY POST-FRONTAL SFC WINDS AND DEVELOPING
LLVL COLD CONVEYOR IN-WRAPPING FROM THE NORTHWEST. BRISK WEST WINDS
OF 15 TO 25+ MPH SHOULD COLD AIR ADVECT TEMPS INTO THE UPPER TEENS
IN THE NORTHWEST...TO THE MID 20S IN THE EAST BY THU MORNING. THE
12Z RUNS THEN SUGGEST THAT AS 1035-1040 MB HIGH DUMPS DOWN THE
NORTHWESTERN PLAINS AND TIGHT CYCLONIC GRADIENT LINGERS SOME OFF
NORTHERN GRT LKS DEEP LOW PRESSURE CENTER...WINDY CONDITIONS TO
CONTINUE THROUGH AT LEAST MIDDAY THU WITH AMBIENT TEMPS ONLY
RECOVERING 3-5 DEGREES FROM MORNING VALUES AT 12Z THU. SINGLE DIGIT
ABOVE ZERO WIND CHILLS IN THE NORTHWESTERN HALF OF THE CWA THU AM.
THE ARCTIC FRONT SURGES SOUTH AND PRODUCES TIGHTENING LLVL
BAROCLINICITY AS IT SLOWS UNDER SOUTHWESTERLIES ACRS THE DEEP
SOUTHERN PLAINS TO SOUTHEASTERN OH RVR VALLEY. ALONG AND NORTH OF
THIS THERMAL RIBBON TO BE AN AXIS FOR WINTER STORM/ICE CONDITIONS
INTO FRI AND THERE IS STILL SOME VARIANCE BETWEEN THE LATEST RUN
SOLUTIONS OF FRONTAL PLACEMENT AND STRENGTH OF A WAVE RIPPLING UP
ALONG THIS HIGHWAY. THE MAJORITY OF THE 12Z MODEL RUNS STILL KEEP
ANY OVERRUNNING SNOW OFF TO THE SOUTHEAST OF THE CWA THU THROUGH FRI
WITH JUST A MID AND HIGH LEVEL CLOUD DECK MOVING UP ACRS PORTIONS OF
THE CWA LATE IN THE DAY AND OVERNIGHT. BUT THE 12Z RUN NAM AND GEM
ARE MORE BULLISH AND FURTHER NORTH WITH THE OVERRUNNING PRECIP
SHIELD AND CLIP AT LEAST THE SOUTHEASTERN THIRD OF THE DVN CWA WITH
LIGHT SNOW THU NIGHT INTO FRI MORNING. FOR NOW WILL MAINTAIN SLIGHT
CHC POPS ACRS THE FAR SOUTH AND SOUTHEASTERN CORNER OF THE FCST
AREA. MOSTLY CLOUDY...BLUSTERY AND COLD CONDITIONS CONTINUE ON FRI
WITH HIGHS ONLY IN THE UPPER TEENS TO LOWER 20S. THE INCOMING SFC
RIDGE WILL LOOK TO UNFOLD ACRS THE UPPER MS RVR VALLEY FRI NIGHT FOR
CLEARING...SFC WIND DECREASING AND COLD CONDITIONS. MANY LOWS IN THE
SINGLE DIGITS WITH A ZERO EVEN POSSIBLE IN THE NORTHWEST.
SATURDAY AND SUNDAY...THE SFC RIDGE MAINTAINS LOCALLY LONG ENOUGH FOR
A FAIR WX BUT COLD DAY SAT WITH HIGHS IN THE TEENS TO AROUND 20 AS
L/W TROF LOOMS ACRS THE SOUTHWESTERN CONUS/GRT BSN. THE MEDIUM RANGE
SOLUTIONS THEN SUGGEST NORTHERN STREAM UPPER JET ENERGY/TROFFINESS
ACRS WESTERN INTO CENTRAL CANADA TO TRY AND PHASE WITH THIS SW
CONUS LONG WAVE. THE LATEST MODEL RUNS PROBABLY STILL TRYING TO GET A
HANDLE ON THIS PROCESS AND IT WILL BE SUBJECT TO CHANGE...BUT THE
CURRENT SIGNAL SUGGESTS AT LEAST A DECENT SIZED PIECE OF WAVE ENERGY
EJECTING OUT OF THE SOUTHERN PLAINS AND THEN SOMEWHERE UP THE OH
RVR VALLEY OR EVEN FURTHER TO THE NORTHWEST SUNDAY INTO MONDAY. WITH
COLD AIR IN PLACE...THIS COULD SPELL AN EXTENDED PERIOD OF SNOW
MOVING UP ACRS PORTIONS OR ALL OF THE DVN CWA STARING OUT LATE SAT
NIGHT IN THE SOUTHWEST...AND THEN CONTINUING THROUGH LATE SUNDAY
NIGHT OR EARLY MON MORNING. THE CURRENT MODELS INCLUDING THE 12Z RUN
GFS AND ECMWF SUGGEST THE BETTER MOISTURE TRANSPORT TO FUEL HEAVIER
PRECIP TO GET PINCHED OFF/REMAIN TO THE SOUTH AND SOUTHEAST OF THE
LOCAL FCST AREA...WITH JUST SECONDARY SNOWS OF 1-3 INCHES ACRS THE
DVN CWA BY 12Z MON...SNOW MOVING OUT JUST AFTER THAT TIME-FRAME. BUT
THE DURATION/24 HRS OF ROUNDS OF AT LEAST LIGHT TO OCCASIONAL
MODERATE SNOW AND HIGHER LSR/S SUGGEST AMOUNTS COULD ADD UP TO BE
MORE. IF THE MOISTURE CONVEYOR IS LESS IMPEDED AND THE SYSTEM PULLS
UP FURTHER TO THE NORTHWEST...THERE MAY BE THE POTENTIAL FOR A MORE
SIGNIFICANT WINTER STORM IN PORTIONS OF OR CLOSE TO THE LOCAL AREA.
A WINDOW TO WATCH FOR SURE...AND WILL HAVE TO SEE HOW ADDITIONAL
MODEL RUNS BEHAVE AND HANDLE THE PHASING PROCESS. WILL RAISE THE CHC
POPS FOR NOW FOR SUNDAY NIGHT.
NEXT MONDAY AND TUESDAY...THE LONGER RANGE SIGNALS SUGGEST THAT
AFTER WHAT KIND OF SYSTEM CAN MAKE IT THROUGH OR CLOSE TO THE AREA
SUNDAY INTO EARLY MONDAY...A VERY COLD AIRMASS THEN LOOMS ACRS
CANADA. THE FRESHLY PHASED L/W TROF WILL THEN BECOME COLD CORE AND
ACT AS AN ARCTIC CONDUIT ALLOWING A COLD DUMP DOWN THE NORTHERN
PLAINS AND UPPER MIDWEST LATER MONDAY INTO TUE. THE 12Z GFS HAS A
FRIGID H85 MB COLD POOL OF -20 TO -26C BARRELING IT/S WAY DOWN
ACRS MOST OF THE CWA BY 12Z TUE...THE 12Z ECMWF IS ADVERTISING -19 TO
-21C. EVEN WITH MIXING WINDS WHICH WILL BE BRISK IN THIS TYPE OF
CAA UNDER CYCLONIC FLOW...TEMPS BY TUE MORNING MAY GO SUB-ZERO. MAY
BE WIND CHILL ADVISORY CRITERIA ATTAINED IN PORTIONS OF THE AREA LATE
MON NIGHT AND THROUGH MIDDAY TUE. WELL AGAIN...MANY SYSTEMS AND
PHASING PROCESSES TO GO THROUGH TO GET TO THIS EXTENDED PERIOD BUT
WILL START TO TREND TEMPS DOWN. ..12..
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1135 PM CST TUE DEC 3 2013
LOW CLOUDS AND/OR FOG TO RESULT IN WIDESPREAD IFR/LIFR CONDITIONS
WITH AREAS OF VLIFR CONDITIONS IN DENSE FOG THROUGH WED AM.
A COLD FRONT WILL MOVE THROUGH THE TERMINALS WED AFTN AND PUSH
THE FOG OUT AS WINDS TURN GUSTY FROM WEST/NORTHWEST AT 15-25 KTS.
SOME SPOTTY DRIZZLE AND LIGHT RAIN CAN BE EXPECTED LATER WED AM
INTO THE AFTN. ANTICIPATE VISIBILITIES TO IMPROVE TO VFR AFTER THE
FRONTAL PASSAGE WITH CIGS GENERALLY MVFR.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR BENTON-BUCHANAN-
CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-IOWA-
JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-
MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR BUREAU-CARROLL-
HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-MERCER-
PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.
MO...DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR CLARK-SCOTLAND.
&&
$$
UPDATE...05
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...12
AVIATION...05
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
518 PM CST Thu Dec 5 2013
...Updated aviation section...
.SYNOPSIS...
ISSUED AT 1115 AM CST THU DEC 5 2013
At 12z Thursday a 1400-160kt 300mb jet extended from northeast
Colorado into the western Great Lakes. Another upper level jet was
located near the based of the 500mb trough that was positioned from
southern California into southwest Montana. A -25 to -32c 500mb
thermal trough was located near the four corners region. A surface
to 850mb ridge axis was located across from western Nebraska into
western Oklahoma and a surface cold front extended from eastern
Colorado south southeast across eastern New Mexico into west
central Texas.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 217 PM CST THU DEC 5 2013
Upper level through that was located across southern California
and Nevada earlier today will track east and cross New Mexico by
late day. Ahead of this this upper trough some mid level moisture
will linger across western Kansas. Backing 700mb winds ahead of
this upper wave appears to enhance frontogenesis across portions
of southwest Kansas late today and early this evening which may
give rise to a period of steady light to moderate snow. Both the
NAM, GFS, and even the RAP hints at enhanced precipitation briefly
ahead of this wave along this baroclinic zone so will follow this
trend through midnight as the upper level trough moves out into
the central high plains. Given the potential for a period of
steadier snow early tonight could easily see snowfall
accumulations in the one to two inch range given the high liquid
to snow ratio. The area more favorable for this measurable
snowfall still appears to be along and south of a Ulysses to Dodge
City to Pratt line. Snow totals of around two inches still not out
of the question near the Oklahoma border so will trim several
counties out of the current winter weather advisory.
Tonight the dewpoint will be at or several degrees below zero
under mostly cloudy skies. Temperatures will be slow to fall this
evening but at this time given these expected low dewpoints, last
nights temperatures across northwest Kansas, and the low levels
cooling by a couple more degrees have decided to stay close to the
guidance for overnight lows. Given these overnight lows ranging
from around 1 degree in west central Kansas to near 10 degrees in
south central Kansas along with wind speeds of around 10 mph the
wind chills by early Friday morning are expected to fall back into
the -8 to -15 degree range. The coldest wind chills early Friday
morning will be across west central Kansas so will be issuing a
wind chill advisory for this area late tonight/early Friday.
On Friday the upper level trough will move east into the mid
Mississippi valley. Subsidence behind this disturbance may give
rise to some breaks of sun late in the day as high pressure at the
surface will continue to build into western Kansas. Despite to
break of sunshine the 900-850mb temperatures continue to support
highs only in the teens Friday afternoon.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 209 PM CST THU DEC 5 2013
Friday night:
Sfc high pressure will shift off to the east Friday night. This will
result in northeasterly winds eventually shifting southeast on the backside
of said departing high. A cold night is expected with minimums near
0F. Would not rule out a few negative values if skies clear more than
expected. Will have to watch for the potential for a wind chill advisory
during the overnight and morning hours.
Saturday and beyond:
The forecast becomes a bit more interesting during the weekend. An amplified
trof will eject from the central Rockies and out across the plains by
Sunday. This wave does have some upper level dynamics associated with
it (140-150 kt jet streak traverses across the forecast area of responsibility).
At the low levels, fairly intense warm air advection, 280-290 Kelvin
isentropic lift, and 850-600 mb increasing frontogenesis will lead
to snow late Saturday and into Sunday. The more enhanced area of said
parameters is forecast along and north of the 850 mb pressure perturbation
...basically the northern half of the forecast area. Models still show
low end snow advisory amounts along and north of highway 96. Even some
of the GEFS members show 2-4" of snow. There is huge bust potential
in temperatures for Sunday, should this snow/snow pack/cloud cover come
into fruition. The ECE shows a high of 8 for KDDC versus 22 from the
MEX. Will apply a slight bias towards the ECMWF solution versus the
GFS. Boise verification shows this guidance doing better than the
MEX with the current cold air mass over Kansas.
After Sunday, the forecast will remain precipitation free as isentropic
downglide and subsidence develops in the wake of the departing synoptic
trof. There is some question of when this cold air will be dislodged
and more of a low level 850 mb downslope plume will develop. The ECMWF
indicates this possibility of seeing "warmer" temperatures (i.e. above
freezing) by mid to late next week. The deterministic runs have been
fairly consistent over the last few days.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 515 PM CST THU DEC 5 2013
Light snow showers will be possible across the DDC and GCK TAF
sites over the next couple of hours. This will bring MVFR
conditions to these terminals. The HYS terminal should remain dry
with cloudy skies. Winds will generally be from the north at 5 to
10 knots throughout the night into tomorrow morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 5 15 0 16 / 70 0 0 30
GCK 2 15 0 13 / 50 0 0 30
EHA 2 13 1 17 / 80 0 0 30
LBL 5 15 0 15 / 80 0 0 30
HYS 4 15 0 15 / 20 0 0 40
P28 10 21 4 20 / 50 10 0 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from Midnight CST /11 PM MST/ tonight to 9
AM CST /8 AM MST/ Friday FOR KSZ043-044-061>063.
WINTER WEATHER ADVISORY until 9 PM CST this evening FOR
KSZ084>088.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Sugden
AVIATION...Hovorka_42
AREA FORECAST DISCUSSION...CORRECTED
NWS GOODLAND KS
236 PM MST WED DEC 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 223 PM MST WED DEC 4 2013
ARCTIC COLD HAS ENTERED THE CWA AND IS EXPECTED TO STICK AROUND FOR
A WHILE. SOME LIGHT SNOW FELL THIS MORNING...WITH HEAVIEST BANDS
OVER EASTERN COLORADO BRINGING NEARLY AN INCH IN A FEW SPOTS.
TONIGHT ANOTHER ROUND OF SNOWFALL IS EXPECTED WHICH COULD BRING A
QUICK INCH IN A FEW SPOTS...BUT OTHERWISE THE COLD WILL BE THE MAIN
HAZARD IN THE SHORT TERM.
TODAY...SUBSIDENCE ACROSS THE TRI-STATE LEAD TO SNOWFALL ENDING AND
EVEN SOME CLEARING SKIES...AND HIGHS WERE A CHALLENGE OF BALANCING
THE ADDITIONAL SOLAR RADIATION WITH COLD AIR ADVECTION. WINDS ARE A
BIT STRONGER THAN THE ORIGINAL FORECAST...BUT A BLEND OF 12Z MOS
GUIDANCE HANDLED THE STRONGER WINDS A LITTLE BETTER THAN MOST OF THE
OTHER GUIDANCE.
TONIGHT...MUCH OF EASTERN COLORADO AND PARTS OF NW KANSAS/SW
NEBRASKA WILL REACH LOWS NEAR OR BELOW ZERO...APPROACHING RECORD
COLD VALUES. A QUICK CHANCE FOR SNOWFALL DUE TO A NARROW BAND
ENHANCED FRONTOGENESIS AS SUGGESTED BY SHORT RANGE GUIDANCE. A FEW
SPOTS NEAR AND SOUTH OF I-70 COULD SEE UP TO AN INCH...BUT ANY
SNOWFALL THAT DOES FALL WILL BE QUICK TO EXIT. SNOWFALL AND CLOUD
COVER WILL LIMIT TEMPS IN THE EVENING HOURS...BUT ONCE THE SNOW
SHOWERS AND CLOUDS MOVE OUT TEMPERATURES WILL DROP RAPIDLY AS COLD
AIR PUSHES SOUTHWARD...850 TEMPS DROPPING TO NEAR -20 C...VERY COLD
EVEN BY WINTER STANDARDS. LOWS WILL BE NEAR TO BELOW
ZERO...APPROACHING RECORD VALUES FOR MANY LOCATIONS. COMBINED WITH
WINDS OF 20-25 MPH AM VERY CONFIDENT ADVISORY-LEVEL WIND CHILL
VALUES AS WIND CHILLS DROP TO -15 TO -25...ESPECIALLY IN EASTERN
COLORADO. IF SKIES CLEAR AS RAPID AS THE RUC IS INDICATING...EVEN
COLDER TEMPS/WIND CHILLS ARE POSSIBLE.
THURSDAY...COLD. HIGHS WILL STRUGGLE TO REACH THE TEENS...EVEN WITH
PARTIAL SUNSHINE. WINDS WILL BE LIGHT...WITH WIND CHILLS WILL BE
NEAR ZERO MUCH OF THE DAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 223 PM MST WED DEC 4 2013
THURSDAY NIGHT-FRIDAY NIGHT...H5 LONGWAVE TROUGH WILL REMAIN IN
PLACE WITH ARCTIC AIR MASS AT THE SURFACE. LOOKS LIKE THERE WILL BE
VERY LITTLE CHANGE IN TEMPS WITH HIGHS IN THE TEENS AND LOWS AROUND
ZERO. MY CURRENT LOW TEMP FORECAST IS A CONSERVATIVE BLEND...AND IF
SKIES CLEAR NEAR DAYBREAK FRIDAY MORNING WE COULD SEE RECORD LOWS IN
THE -5 TO -15F BELOW ZERO RANGE. EVEN WITH SLIGHTLY WARMER TEMPS WE
WILL PROBABLY NEED TO CONSIDER WIND CHILL ADVISORIES BOTH NIGHTS.
MODELS SHOW SOME WEAK ENERGY ROTATING THROUGH THE BASE ON THE LARGE
SCALE TROUGH. BEYOND INCREASING CLOUD COVER THE FORECAST SHOULD
REMAIN DRY DURING THESE PERIODS. I DECIDED AGAINST MENTION OF
FLURRIES...THOUGH I COULDNT RULE OUT A FEW FLURRIES DURING THE
DAYTIME PERIOD THURSDAY IF WE ARE ABLE TO GET SOME WEAK INSTABILITY.
SATURDAY-SUNDAY NIGHT...THE NEXT GOOD CHANCE FOR ACCUMULATING SNOW
LOOKS TO ARRIVE THIS WEEKEND WHEN A SHORTWAVE TROUGH ORIGINATING
OVER THE PACIFIC NW MOVES TO THE FOUR CORNERS REGION SATURDAY AND
ACROSS THE PLAINS AS A NEGATIVELY TILTED TROUGH SUNDAY. VERY GOOD
FORCING AHEAD OF THIS FEATURE AND DECENT MOISTURE ADVECTION SHOULD
COMBINE TO PRODUCE ACCUMULATING SNOW FOR A LARGE PORTION OF THE
PLAINS. MODELS GENERALLY SHOW SIMILAR TIMING ON THIS
FEATURE...HOWEVER THERE IS LESS CONTINUITY ON THE TRACK AND THIS
WILL HAVE A LARGE IMPACT ON SNOW TOTALS OVER OUR CWA. DURING THIS
FORECAST UPDATE I BUMPED POPS UP SOME ON SATURDAY NIGHT AND SUNDAY
TO HIGH CHANCE CATEGORY WITH INCREASING CONFIDENCE IN MEASURABLE
SNOW. BEST GUESS BASED ON A MEAN STORM TRACK PUTS SNOW AMOUNTS IN
THE 1-3" RANGE OVER OUR CWA WITH THE HIGHEST AMOUNTS ACROSS THE
SOUTHEAST WHERE BETTER FORCING ASSOCIATED WITH MID LEVEL
FRONTOGENETICAL BAND HAS A BETTER CHANCE OF SETTING UP.
MONDAY-WEDNESDAY...DRY FORECAST IS EXPECTED WITH UPPER LEVEL
CONFLUENCE AND H5 PATTERN BECOMING SLIGHTLY MORE ZONAL. MODELS DO
ADVERTISE A GRADUAL WARMING TREND WITH HIGHS FINALLY APPROACHING (OR
GOING ABOVE) FREEZING BY TUESDAY AND WEDNESDAY. NORTHERN JET STREAM
STILL APPEARS TO BE VERY ACTIVE HOWEVER SO ADDITIONAL REINFORCING
SHOTS OF COLD AIR COULD KEEP OUR TEMPERATURES BELOW NORMAL THROUGH
NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1048 AM MST WED DEC 4 2013
MVFR TO IFR CONDITIONS EXPECTED WITHIN THE TAF PERIOD AT MCK AND
GLD. WINDS 20-25 KTS THIS AFTERNOON OUT OF THE NORTHWEST AT BOTH
SITES WILL DECREASE DRAMATICALLY THIS EVENING AND THROUGH THE REST OF
THE TAF PERIOD.
A LIGHT BUT VISIBILITY-REDUCING BAND OF SNOW IS APPROACHING
GLD...AND WHILE ITS APPEARANCE IS MEAGER ON RADAR AND
SATELLITE...OBS AT KITR INDICATED REDUCTION TO IFR CONDITIONS. FOR
THIS REASON HAVE A TEMPO FOR GLD FOR A QUICK BAND OF
SNOW...OTHERWISE VFR CONDITIONS THROUGH THE EARLY AFTERNOON WHEN
ANOTHER ROUND OF SNOWFALL IS EXPECTED TO IMPACT THE SITE. THIS
SECOND ROUND WILL BE RELATIVELY QUICK...ENDING LATE THIS EVENING.
VFR CONDITIONS THROUGH THE REST OF THE PERIOD AS CEILING HEIGHTS
RISE.
AT MCK SOME CLEARING ON SATELLITE AT THE 17Z HOUR...BUT ASOS
REPORTING AN MVFR CLOUD DECK STILL IN PLACE. REGARDLESS...SOME
CLEARING IS EXPECTED IN THE SHORT TERM BEFORE VFR CLOUD COVER
RETURNS. CONDITIONS WILL BE VFR FOR THE REST OF THE PERIOD.
&&
.CLIMATE...
ISSUED AT 223 PM MST WED DEC 4 2013
LOW TEMPERATURES WILL APPROACH RECORD VALUES TONIGHT.
CURRENT DAILY RECORD LOWS FOR THURSDAY (DEC 5)...
GOODLAND.....-8 (1972)
HILL CITY....-5 (1909)
BURLINGTON...-11 (1972)
MCCOOK.......-10 (1909)
YUMA.........-5
TRIBUNE......-2
COLBY........-8
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND CHILL ADVISORY UNTIL 11 AM MST /NOON CST/ THURSDAY FOR
KSZ001>003-013-014-027.
CO...WIND CHILL ADVISORY UNTIL 11 AM MST THURSDAY FOR COZ090>092.
NE...WIND CHILL ADVISORY UNTIL 11 AM MST /NOON CST/ THURSDAY FOR
NEZ079>081.
&&
$$
SHORT TERM...JJM
LONG TERM...DR
AVIATION...JJM
CLIMATE...JJM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
227 PM MST WED DEC 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 223 PM MST WED DEC 4 2013
ARCTIC COLD HAS ENTERED THE CWA AND IS EXPECTED TO STICK AROUND FOR
A WHILE. SOME LIGHT SNOW FELL THIS MORNING...WITH HEAVIEST BANDS
OVER EASTERN COLORADO BRINGING NEARLY AN INCH IN A FEW SPOTS.
TONIGHT ANOTHER ROUND OF SNOWFALL IS EXPECTED WHICH COULD BRING A
QUICK INCH IN A FEW SPOTS...BUT OTHERWISE THE COLD WILL BE THE MAIN
HAZARD IN THE SHORT TERM.
TODAY...SUBSIDENCE ACROSS THE TRI-STATE LEAD TO SNOWFALL ENDING AND
EVEN SOME CLEARING SKIES...AND HIGHS WERE A CHALLENGE OF BALANCING
THE ADDITIONAL SOLAR RADIATION WITH COLD AIR ADVECTION. WINDS ARE A
BIT STRONGER THAN THE ORIGINAL FORECAST...BUT A BLEND OF 12Z MOS
GUIDANCE HANDLED THE STRONGER WINDS A LITTLE BETTER THAN MOST OF THE
OTHER GUIDANCE.
TONIGHT...MUCH OF EASTERN COLORADO AND PARTS OF NW KANSAS/SW
NEBRASKA WILL REACH LOWS NEAR OR BELOW ZERO...APPROACHING RECORD
COLD VALUES. A QUICK CHANCE FOR SNOWFALL DUE TO A NARROW BAND
ENHANCED FRONTOGENESIS AS SUGGESTED BY SHORT RANGE GUIDANCE. A FEW
SPOTS NEAR AND SOUTH OF I-70 COULD SEE UP TO AN INCH...BUT ANY
SNOWFALL THAT DOES FALL WILL BE QUICK TO EXIT. SNOWFALL AND CLOUD
COVER WILL LIMIT TEMPS IN THE EVENING HOURS...BUT ONCE THE SNOW
SHOWERS AND CLOUDS MOVE OUT TEMPERATURES WILL DROP RAPIDLY AS COLD
AIR PUSHES SOUTHWARD...850 TEMPS DROPPING TO NEAR -20 C...VERY COLD
EVEN BY WINTER STANDARDS. LOWS WILL BE NEAR TO BELOW
ZERO...APPROACHING RECORD VALUES FOR MANY LOCATIONS. COMBINED WITH
WINDS OF 20-25 MPH AM VERY CONFIDENT ADVISORY-LEVEL WIND CHILL
VALUES AS WIND CHILLS DROP TO -15 TO -25...ESPECIALLY IN EASTERN
COLORADO. IF SKIES CLEAR AS RAPID AS THE RUC IS INDICATING...EVEN
COLDER TEMPS/WIND CHILLS ARE POSSIBLE.
THURSDAY...COLD. HIGHS WILL STRUGGLE TO REACH THE TEENS...EVEN WITH
PARTIAL SUNSHINE. WINDS WILL BE LIGHT...WITH WIND CHILLS WILL BE
NEAR ZERO MUCH OF THE DAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 223 PM MST WED DEC 4 2013
THURSDAY NIGHT-FRIDAY NIGHT...H5 LONGWAVE TROUGH WILL REMAIN IN
PLACE WITH ARCTIC AIR MASS AT THE SURFACE. LOOKS LIKE THERE WILL BE
VERY LITTLE CHANGE IN TEMPS WITH HIGHS IN THE TEENS AND LOWS AROUND
ZERO. MY CURRENT LOW TEMP FORECAST IS A CONSERVATIVE BLEND...AND IF
SKIES CLEAR NEAR DAYBREAK FRIDAY MORNING WE COULD SEE RECORD LOWS IN
THE -5 TO -15F BELOW ZERO RANGE. EVEN WITH SLIGHTLY WARMER TEMPS WE
WILL PROBABLY NEED TO CONSIDER WIND CHILL ADVISORIES BOTH NIGHTS.
MODELS SHOW SOME WEAK ENERGY ROTATING THROUGH THE BASE ON THE LARGE
SCALE TROUGH. BEYOND INCREASING CLOUD COVER THE FORECAST SHOULD
REMAIN DRY DURING THESE PERIODS. I DECIDED AGAINST MENTION OF
FLURRIES...THOUGH I COULDNT RULE OUT A FEW FLURRIES DURING THE
DAYTIME PERIOD THURSDAY IF WE ARE ABLE TO GET SOME WEAK INSTABILITY.
SATURDAY-SUNDAY NIGHT...THE NEXT GOOD CHANCE FOR ACCUMULATING SNOW
LOOKS TO ARRIVE THIS WEEKEND WHEN A SHORTWAVE TROUGH ORIGINATING
OVER THE PACIFIC NW MOVES TO THE FOUR CORNERS REGION SATURDAY AND
ACROSS THE PLAINS AS A NEGATIVELY TILTED TROUGH SUNDAY. VERY GOOD
FORCING AHEAD OF THIS FEATURE AND DECENT MOISTURE ADVECTION SHOULD
COMBINE TO PRODUCE ACCUMULATING SNOW FOR A LARGE PORTION OF THE
PLAINS. MODELS GENERALLY SHOW SIMILAR TIMING ON THIS
FEATURE...HOWEVER THERE IS LESS CONTINUITY ON THE TRACK AND THIS
WILL HAVE A LARGE IMPACT ON SNOW TOTALS OVER OUR CWA. DURING THIS
FORECAST UPDATE I BUMPED POPS UP SOME ON SATURDAY NIGHT AND SUNDAY
TO HIGH CHANCE CATEGORY WITH INCREASING CONFIDENCE IN MEASURABLE
SNOW. BEST GUESS BASED ON A MEAN STORM TRACK PUTS SNOW AMOUNTS IN
THE 1-3" RANGE OVER OUR CWA WITH THE HIGHEST AMOUNTS ACROSS THE
SOUTHEAST WHERE BETTER FORCING ASSOCIATED WITH MID LEVEL
FRONTOGENETICAL BAND HAS A BETTER CHANCE OF SETTING UP.
MONDAY-WEDNESDAY...DRY FORECAST IS EXPECTED WITH UPPER LEVEL
CONFLUENCE AND H5 PATTERN BECOMING SLIGHTLY MORE ZONAL. MODELS DO
ADVERTISE A GRADUAL WARMING TREND WITH HIGHS FINALLY APPROACHING (OR
GOING ABOVE) FREEZING BY TUESDAY AND WEDNESDAY. NORTHER JET STREAM
STILL APPEARS TO BE VERY ACTIVE HOWEVER SO ADDITIONAL REINFORCING
SHOTS OF COLD AIR COULD KEEP OUR TEMPERATURES BELOW NORMAL THROUGH
NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1048 AM MST WED DEC 4 2013
MVFR TO IFR CONDITIONS EXPECTED WITHIN THE TAF PERIOD AT MCK AND
GLD. WINDS 20-25 KTS THIS AFTERNOON OUT OF THE NORTHWEST AT BOTH
SITES WILL DECREASE DRAMATICALLY THIS EVENING AND THROUGH THE REST OF
THE TAF PERIOD.
A LIGHT BUT VISIBILITY-REDUCING BAND OF SNOW IS APPROACHING
GLD...AND WHILE ITS APPEARANCE IS MEAGER ON RADAR AND
SATELLITE...OBS AT KITR INDICATED REDUCTION TO IFR CONDITIONS. FOR
THIS REASON HAVE A TEMPO FOR GLD FOR A QUICK BAND OF
SNOW...OTHERWISE VFR CONDITIONS THROUGH THE EARLY AFTERNOON WHEN
ANOTHER ROUND OF SNOWFALL IS EXPECTED TO IMPACT THE SITE. THIS
SECOND ROUND WILL BE RELATIVELY QUICK...ENDING LATE THIS EVENING.
VFR CONDITIONS THROUGH THE REST OF THE PERIOD AS CEILING HEIGHTS
RISE.
AT MCK SOME CLEARING ON SATELLITE AT THE 17Z HOUR...BUT ASOS
REPORTING AN MVFR CLOUD DECK STILL IN PLACE. REGARDLESS...SOME
CLEARING IS EXPECTED IN THE SHORT TERM BEFORE VFR CLOUD COVER
RETURNS. CONDITIONS WILL BE VFR FOR THE REST OF THE PERIOD.
&&
.CLIMATE...
ISSUED AT 223 PM MST WED DEC 4 2013
LOW TEMPERATURES WILL APPROACH RECORD VALUES TONIGHT.
CURRENT DAILY RECORD LOWS FOR THURSDAY (DEC 5)...
GOODLAND.....-8 (1972)
HILL CITY....-5 (1909)
BURLINGTON...-11 (1972)
MCCOOK.......-10 (1909)
YUMA.........-5
TRIBUNE......-2
COLBY........-8
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND CHILL ADVISORY UNTIL 11 AM MST /NOON CST/ THURSDAY FOR
KSZ001>003-013-014-027.
CO...WIND CHILL ADVISORY UNTIL 11 AM MST THURSDAY FOR COZ090>092.
NE...WIND CHILL ADVISORY UNTIL 11 AM MST /NOON CST/ THURSDAY FOR
NEZ079>081.
&&
$$
SHORT TERM...JJM
LONG TERM...DR
AVIATION...JJM
CLIMATE...JJM
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
222 PM CST Wed Dec 4 2013
...Update to long term discussion...
.SYNOPSIS...
ISSUED AT 1102 AM CST WED DEC 4 2013
At 12z Wednesday a 300mb jet extended from southern California
into far western Nebraska. A -35c to -37c 500mb low was located
over southeastern Idaho with an upper level trough extending
southwest of this upper low into southern California. Ahead of
this upper level trough 80 to 90meter 12hour height rises were
observed near the four corners region which was where the left
exit region of a 300mb +100kt jet was positioned. A 700mb
baroclinic zone stretched from the four corners region across
western Kansas and into southeastern Nebraska with an area of
higher dewpoints observed along this baroclinic zone. The 850mb
temperatures at 12z Wednesday across the central plains varied
from -3c at Amarillo to -9c at Dodge city to -16c at North Platte.
This a 18c to 25c drop when comparing the 850mb temperatures from 12z
Wednesday to 12z Tuesday. Dodge City and North Platte soundings
from 12z also indicated a fairly deep layer of moisture which
extended from near the surface to at least the 800mb level.
&&
.SHORT TERM...(This evening through Thursday)
ISSUED AT 147 PM CST WED DEC 4 2013
19z visible satellite loop indicating some clearing skies across
western Kansas as the low clouds gradually erode. Further west mid
level cloud cover/moisture was on the increase and this appears to
be related to a 700mb baroclinic zone that extended from northeast
Colorado into Nebraska. Tonight 700mb frontogenesis will be
improving along this mid level baroclinic zone as the right
entrance region of a 300mb jet crosses western Kansas. Based on
the NAM and RAP at 18z Wednesday this 700mb baroclinic zone should
be located across northeast Colorado 18z and based on the latest
composite mosaic radar loop these models appear to have a decent
handle on this. As a result will follow the 700mb baroclinic zone
from NAM and RAP overnight and place the better chances for
measurable snow along this boundary given the improving
frontogenesis and the location of the right entrance region of an
upper level jet as it crosses the central plains during the
overnight hours.
Initial thoughts for snow amounts tonight...a brief period of
steady light to even moderate snow may accompany the jet steak
which may result in a quick inch of snow across portions of west
central and north central Kansas. Have therefore place snow
accumulations of 1 to around 1.5 inches in this this area between
00z Thursday and 12z Thursday. Further south some light
snow/flurries will still be possible, however given the loss of
the upper level dynamics lower snow amounts are anticipated.
On Thursday the better mid level forcing will be located near the
Oklahoma border through much of the day as a southern branch upper
level disturbance approaches southwest Kansas from New Mexico.
Another brief period of steady light to moderate snow will be be
possible during the day across far southwest Kansas and near the
Oklahoma border. Once again 1 to 2 inches of snowfall will be
possible with this steadier snow and lower snow amounts further
north. At this time snow totals over the next 24 to 36 hours are
expected to be mainly between 1 to 2 inches so inserted these snow
totals into the hazardous weather outlook but will not issue a
winter weather advisory at this time.
Wind chill values towards daybreak will fall back mainly into the
5 to 10 degrees below zero range with wind chill readings
approaching -15c in a few locations of west central Kansas. On
Thursday as afternoon temperatures struggle to reach the 15 to
near 20 degree range the wind chill values are expected to be
mainly in the single digits.
.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 222 PM CST WED DEC 4 2013
Thursday night/Friday:
Precipitation will be quickly diminishing after 00Z Friday as the 700
hPa frontogenesis and 285 Kelvin isentropic lift slides off to the southeast.
Minimums will continue to be cold and in the single digits. will have
to watch out for the possible need for a wind chill advisory as apparent
temperatures approach -15F, particularly during the morning on Friday.
Otherwise, a precipitation free forecast is expected Friday as isentropic
downglide develops in the wake of the passing synoptic trof. Maximums
Friday will be in the teens and have gone with the colder bias correct
guidance as 850 hPa temperatures remain 2 to 3 standard deviations below
normal.
Saturday and beyond:
250 hPa flow will eventually transition from westerly Saturday to southwesterly
Sunday as the next 400 hPa pv anomaly moves across the central Rockies
and eventually ejects out across the prairies. This signature is quite
impressive per ECMWF fields and displays the classic treble clef signature.
At the low levels, 850-600 hPa frontogenesis and 280-290 Kelvin isentropic
lift develops across west central Kansas Sunday. Have ramped up precipitation
probabilities in this region during the day. The GEM and ECMWF indicate
the potential for a low end snow advisory for Sunday. This is something
to continue to watch as we get closer to the event. Otherwise, the rest
of the forecast will feature fairly tranquil weather and cold temperatures.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1102 AM CST WED DEC 4 2013
BUFR soundings indicating the MVFR cigs, as of 16z, will be
gradually improving to low VFR conditions at all three taf sites
around 21z. These low VFR cigs are then expected to linger through
the overnight period with a chance of light snow developing after
midnight as an area of mid level forcing moves across western
Kansas. At this time the better opportunity for snow at HYS and
GCK will be from 06z to 12z and DDC from around 12z to 18z. Gusty
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 9 16 6 16 / 30 60 60 0
GCK 9 16 4 14 / 50 40 40 0
EHA 7 14 5 15 / 50 50 50 0
LBL 11 17 7 16 / 40 80 80 0
HYS 8 18 1 15 / 60 20 20 0
P28 14 22 11 19 / 20 50 50 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Sugden
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
150 PM CST Wed Dec 4 2013
...Updated short term discussion...
.SYNOPSIS...
ISSUED AT 1102 AM CST WED DEC 4 2013
At 12z Wednesday a 300mb jet extended from southern California
into far western Nebraska. A -35c to -37c 500mb low was located
over southeastern Idaho with an upper level trough extending
southwest of this upper low into southern California. Ahead of
this upper level trough 80 to 90meter 12hour height rises were
observed near the four corners region which was where the left
exit region of a 300mb +100kt jet was positioned. A 700mb
baroclinic zone stretched from the four corners region across
western Kansas and into southeastern Nebraska with an area of
higher dewpoints observed along this baroclinic zone. The 850mb
temperatures at 12z Wednesday across the central plains varied
from -3c at Amarillo to -9c at Dodge city to -16c at North Platte.
This a 18c to 25c drop when comparing the 850mb temperatures from 12z
Wednesday to 12z Tuesday. Dodge City and North Platte soundings
from 12z also indicated a fairly deep layer of moisture which
extended from near the surface to at least the 800mb level.
&&
.SHORT TERM...(This evening through Thursday)
ISSUED AT 147 PM CST WED DEC 4 2013
19z visible satellite loop indicating some clearing skies across
western Kansas as the low clouds gradually erode. Further west mid
level cloud cover/moisture was on the increase and this appears to
be related to a 700mb baroclinic zone that extended from northeast
Colorado into Nebraska. Tonight 700mb frontogenesis will be
improving along this mid level baroclinic zone as the right
entrance region of a 300mb jet crosses western Kansas. Based on
the NAM and RAP at 18z Wednesday this 700mb baroclinic zone should
be located across northeast Colorado 18z and based on the latest
composite mosaic radar loop these models appear to have a decent
handle on this. As a result will follow the 700mb baroclinic zone
from NAM and RAP overnight and place the better chances for
measurable snow along this boundary given the improving
frontogenesis and the location of the right entrance region of an
upper level jet as it crosses the central plains during the
overnight hours.
Initial thoughts for snow amounts tonight...a brief period of
steady light to even moderate snow may accompany the jet steak
which may result in a quick inch of snow across portions of west
central and north central Kansas. Have therefore place snow
accumulations of 1 to around 1.5 inches in this this area between
00z Thursday and 12z Thursday. Further south some light
snow/flurries will still be possible, however given the loss of
the upper level dynamics lower snow amounts are anticipated.
On Thursday the better mid level forcing will be located near the
Oklahoma border through much of the day as a southern branch upper
level disturbance approaches southwest Kansas from New Mexico.
Another brief period of steady light to moderate snow will be be
possible during the day across far southwest Kansas and near the
Oklahoma border. Once again 1 to 2 inches of snowfall will be
possible with this steadier snow and lower snow amounts further
north. At this time snow totals over the next 24 to 36 hours are
expected to be mainly between 1 to 2 inches so inserted these snow
totals into the hazardous weather outlook but will not issue a
winter weather advisory at this time.
Wind chill values towards daybreak will fall back mainly into the
5 to 10 degrees below zero range with wind chill readings
approaching -15c in a few locations of west central Kansas. On
Thursday as afternoon temperatures struggle to reach the 15 to
near 20 degree range the wind chill values are expected to be
mainly in the single digits.
.LONG TERM...(Thursday through Tuesday)
ISSUED AT 345 AM CST WED DEC 4 2013
Medium range models indicate an upper level shortwave pushing east
across the Four Corners Region Thursday setting up the possibility
for precip across portions of western Kansas. As the system
approaches, a series of H5 vort maxes will continue to lift
northeast out of the trough axis in the Desert Southwest and across
the Western High Plains. Meanwhile, an upper level jet exiting the
trough axis will intensify as it climbs northeast across western
Kansas and the panhandles of Texas and Oklahoma. Additionally, the
GFS/ECMWF continue to hint at some H7 frontogenesis bands
transitioning across western Kansas throughout the day. As a
result, enough support will exist to support periods of light snow
across portions of west central, southwest, and central Kansas as
mid/upper level moisture increases somewhat. However, significant
snowfall amounts are still not expected across much of the area
with amounts generally less than 2 inches. Localized higher
amounts cannot be ruled out across extreme southwest Kansas but
confidence is too low to consider issuing any winter weather
headlines. Drier conditions are then expected Friday through
Saturday afternoon as the upper level shortwave opens up and races
off to the northeast. Another round of light precip is possible
Saturday night into Sunday as another upper level trough drops
south out of the Pacific Northwest into the Four Corners Region.
Temperatures will be well below normal Thursday as cold air
continues to filter southward into western Kansas. Surface high
pressure will extend from the high plains of eastern Montana and
eastern Wyoming down into Nebraska and Kansas helping to reinforce
the cold air mass in place across the Western High Plains with H85
temperatures as low as 15C below. Look for highs only up into the
teens(F) and lower 20s(F) Thursday. Similar temperatures are likely
Friday and Saturday with little change in the overall air mass going
into the weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1102 AM CST WED DEC 4 2013
BUFR soundings indicating the MVFR cigs, as of 16z, will be
gradually improving to low VFR conditions at all three taf sites
around 21z. These low VFR cigs are then expected to linger through
the overnight period with a chance of light snow developing after
midnight as an area of mid level forcing moves across western
Kansas. At this time the better opportunity for snow at HYS and
GCK will be from 06z to 12z and DDC from around 12z to 18z. Gusty
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 9 16 6 16 / 30 60 60 0
GCK 9 16 4 14 / 50 40 40 0
EHA 7 14 5 15 / 50 50 50 0
LBL 11 17 7 16 / 40 80 80 0
HYS 8 18 1 15 / 60 20 20 0
P28 14 22 11 19 / 20 50 50 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...JJohnson
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1145 PM MST TUE DEC 3 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 157 PM MST TUE DEC 3 2013
AS OF 3 PM CST...2 PM MST...SKIES ACROSS THE TRI-STATE AREA RANGED
FROM PARTLY CLOUDY TO OVERCAST AS HIGH CIRRUS CONTINUES TO PASS
OVER. TEMPERATURES REACHED THE LOW TO MID 60S ACROSS THE AREA WITH
THE EXCEPTION OF SOUTHWEST NEBRASKA. A BACK DOOR COLD FRONT HAS
MOVED IN FROM THE NORTHEAST...KEEPING THINGS ACROSS THE NORTHEASTERN
THIRD OF THE FORECAST AREA COOLER. WINDS HAVE BEEN FROM THE SOUTH
AHEAD OF THE COLD FRONT AND NORTHEAST BEHIND THE BACKDOOR FRONT. THE
MAIN COLD FRONT WAS FINALLY BEGINNING TO MAKE ITS SURGE INTO
NORTHEAST COLORADO. THE FRONT WAS BLOCKED BY A STRONG LEE TROUGH
CENTERED BETWEEN DENVER AND LIMON. THIS LEE TROUGH IS NOW STARTING
TO MOVE SOUTHEAST FROM LATEST RAP MSL ANALYSIS...ALLOWING THE MAIN
COLD FRONT TO SURGE SOUTH.
FOR THIS AFTERNOON AND TONIGHT...THE STRONG ARCTIC FRONT WILL MAKE
ITS PRESENCE FELT AS IT MOVES SOUTH. TEMPERATURES DROP RAPIDLY BY
THE FRONT AS SEEN BY THE 15 TO 20 DEGREE DROPS IN ONE HOUR AT YUMA
AND AKRON COLORADO. IMMEDIATELY BEHIND THE FRONT...GUSTY NORTH WINDS
ARE EXPECTED. WINDS NEAR WIND ADVISORY CRITERIA HAVE NOT BEEN
OBSERVED AND MODELS HAVE BACKED OFF ON WIND SPEEDS FROM YESTERDAYS
RUNS. THERE COULD BE SOME GUSTS THAT APPROACH WIND ADVISORY CRITERIA
BUT THIS SHOULD NOT BE WIDESPREAD NOR PERSISTENT. LOW TEMPERATURES
TONIGHT SHOULD BE ABLE TO DROP INTO THE LOW 10S TO LOW 20S EVEN WITH
DENSE CLOUD COVER. FOR PRECIPITATION CHANCES...MOST OF THE
PRECIPITATION WILL LIKELY HOLD OFF UNTIL AFTER 00Z WITH CHANCES
GRADUALLY INCREASING THROUGHOUT THE NIGHT. MODELS INDICATE THAT THE
ATMOSPHERE GRADUALLY SATURATES THROUGH THE NIGHT...ALLOWING SNOW TO
BEGIN FALLING THIS EVENING OR EARLY TOMORROW MORNING. SOUTHEAST
PORTIONS OF THE FORECAST AREA SHOULD MISS OUT ON THE PRECIPITATION
FOR THE MOST PART BUT COULD SEEM SOME FLURRIES. ACCUMULATIONS WILL
BE LIGHT AS ALL MODELS SHOW LIGHT QPF WITH HEAVIER AMOUNTS WEST
WHERE TERRAIN EFFECTS AND LIFT ARE STRONGER.
FOR TOMORROW...COLD WEATHER WILL CONTINUE WITH HIGH TEMPERATURES LESS
THAN 10 DEGREES WARMER THAN LOW TEMPERATURES TONIGHT. HIGHS ARE ONLY
ADVERTISED TO BE IN THE LOW 10S OVER NORTHEAST COLORADO TO THE MID
20S OUT NEAR HILL CITY. THIS COULD BE GENEROUS CONSIDERING THAT
DENSE CLOUD COVER AND NORTH WINDS SHOULD PERSIST. CHANCES FOR LIGHT
SNOW CONTINUE IN THE MORNING HOURS BEFORE CHANCES DECREASE ACROSS
NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. CHANCES SHOULD CONTINUE
OVER EAST COLORADO WITH A SLIGHT UPSLOPE COMPONENT AND A BETTER
ATMOSPHERIC MOISTURE PROFILE. AGAIN...ONLY LIGHT ACCUMULATIONS ARE
EXPECTED WITH LITTLE IMPACT TO TRAVEL. ANOTHER THING TO NOTE ABOUT
TOMORROW IS THAT WITH THE NORTH WINDS AND COLD TEMPERATURES...WIND
CHILLS SHOULD REMAIN IN THE SINGLE DIGITS ABOVE ZERO THROUGHOUT THE
DAY WITH BELOW ZERO WIND CHILLS POSSIBLE IN EAST COLORADO. NEEDLESS
TO SAY...TOMORROW WILL BE MUCH COLDER WITH HIGH TEMPERATURES ON THE
ORDER OF 20 TO 45 DEGREES COOLER DEPENDING ON THE LOCATION.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 1139 PM MST TUE DEC 3 2013
ARCTIC AIR WILL BE FIRMLY ENTRENCHED THROUGHOUT THE LONG TERM
PERIOD WITH TEMPERATURES MUCH BELOW NORMAL. BEST CHANCES FOR
PRECIPITATION WILL BE IN THE SATURDAY NIGHT AND SUNDAY PERIOD
WITH A SHORTWAVE TROUGH EJECTING ACROSS THE CENTRAL ROCKIES.
MODELS INDICATE 1 TO 3 INCHES OF LIGHT SNOW POSSIBLE...HIGHEST
AMOUNTS IN THE SOUTHWEST PORTION OF THE FORECAST AREA. THERE ARE
HINTS THAT TEMPERATURES WILL BEGIN TO MODERATE TOWARDS THE END OF
THE PERIOD AS THE UPPER FLOW BECOMES MORE ZONAL AND THE LARGE
TROUGH WHICH WAS RESPONSIBLE FOR THE ARCTIC OUTBREAK LIFTS OUT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 941 PM MST TUE DEC 3 2013
MVFR CIGS CONTINUE AT KGLD AND KMCK AS HIGH PRESSURE BUILDS SOUTH
INTO THE CENTRAL PLAINS BEHIND THE COLD FRONT. METARS INDICATE
LIGHT SNOW OVER THE SOUTHERN NEBRASKA PANHANDLE. THE NAM MODEL
SHOWS SOME LIGHT SNOW POSSIBLE IN KGLD OVERNIGHT BUT THE FORECAST
SOUNDING DOES NOT SUPPORT SNOW UNTIL LATE WEDNESDAY AFTERNOON AND
EARLY EVENING. KMCK HAS EVEN LESS CHANCE FOR SNOW. DYNAMICS SHIFT
SOUTH WEDNESDAY EVENING WITH SOUNDING SHOWING IMPROVING CIGS TO
VFR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...RRH
LONG TERM...024
AVIATION...FS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1212 AM CST Wed Dec 4 2013
...Updated aviation discussion...
.SYNOPSIS...
ISSUED AT 1106 AM CST TUE DEC 3 2013
At 12z Tuesday a -35c 500mb low was located over Idaho/western
Montana. A +100kt 300mb jet streak was located in the based of
this upper low and extended from northern Nevada into southern
Wyoming. 700 mb level difluent flow appears to be located across
eastern Wyoming. This was located near the left exit region of
the 300mb jet. Across the Central Plains earlier this morning the
850mb temperatures ranged from +10C at North Platte to +15c at
Amarillo. Dodge City this morning had a 850mb temperature of +13c.
A surface cold front was located across Nebraska at 12z Tuesday.
North of this surface cold front low clouds, gusty north winds and
light snow/fog were observed from the surface observations across
eastern Wyoming and northwest Nebraska. Surface temperatures under
the status were mainly in the 20s. 850mb temperatures north of
this front varied from -9c at South Dakota to -13c at Glasgow MT.
&&
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 222 PM CST TUE DEC 3 2013
12z NAM and GFS along with the latest HRRR and RAP were all in
decent agreement with a cold front surging south across western
Kansas during the overnight hours. Based on 18z verification
between the models and the surface observations the 2m
temperatures across Nebraska from NAM and HRRR were within 3
degrees of the actual temperature, and both of these models were
close with the surface front location. 12z NAM model soundings
across Nebraska also appeared to be picking up on the status
behind this front as well. As a result will stay close to the NAM
and HRRR on timing of the wind shift overnight along with the
magnitude of the cold air advection that will be developing behind
this front overnight as low clouds thicken across western Kansas.
Given the current temperatures behind this front in northern
Nebraska, status and cold air advection that is forecast to spread
into western Kansas later tonight have decided to stay close the
previous forecast which was also similar to the latest MET
guidance. Gusty north winds at 20 to 30 mph are also expected to
develop for several hours behind this front later tonight based
given the tight surface pressure gradient and 925-850mb winds of
25 to 35 knots. These gusty winds by daybreak will easily result
in wind chill values in the single digits by early Wednesday
morning. Isentropic lift/warm air advection along with a deepening
moist layer across portions of north central Kansas approaches a
depth favorable for some very light precipitation, however at
this time have decided not to introduce any type of very light
precipitation east of 183.
On Wednesday the status will slowly erode during the afternoon
and cold air advection continues in the 900mb to 850mb layer. Based
on the 18z Wednesday and 00z Thursday 850mb temperatures from the
NAM and GFS will undercut the MET/MAV guidance for highs.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 132 PM CST TUE DEC 3 2013
Wednesday night/Thursday:
The 12Z ECMWF, NAM, and GEM were indicating the potential for
some snow Wednesday night but mainly into Thursday as an 145 kt
250 mb jet streak moves across the region. This will create an
ageostrophic response (i.e. acceleration) and cause some synoptic
lift across the forecast area of responsibility. On top of that,
the models indicate low level isentropic lift on top of the cold
airmass. The GFS is the oddball out and was ignored as it did not
match ensemble mean nor the aforementioned consensus in the
deterministic runs. Will have to watch for a sneaky snow advisory
snow amount being met. One fly in the ointment is that the low
levels are very dry (as expected with an Arctic intrusion), so
this could reduce probabilities for more significant precipitation
measurement. Of course, not ready to buy into the thermodynamic
profiles (particularly the NAM) this far out, but did trend with
higher pops, qpf, and lower temperatures. If a snow pack does come
into fruition, the minimums into Friday morning will have to be
watched as they could bottom into negative territory. Otherwise,
midweek will be cold and have gone with bias corrected mos
guidance.
Friday and beyond:
Friday through Saturday will feature a precipitation free forecast as
the region will be between synoptic systems. The next chance of precipitation
in the form of snow will be on Sunday as another trof digs across the
central Rockies and eventually ejects out across the prairies. It is
too early to hammer out details this far out and have stuck with the
weighted blend solution. Temperatures will continue to remain below
normal.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 1211 AM CST WED DEC 4 2013
IFR/LIFR ceilings along with gusty north winds will prevail at the taf
sites through the remainder of tonight. MVFR visibilities will
also occur through the first part of the taf period but this
should improve to VFR between 09z-12z as drier air moves in from
the north. Look for ceilings to improve into MVFR and possibly VFR
categories between 15z-18z Wednesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 28 10 13 5 / 0 10 50 50
GCK 26 11 12 2 / 0 30 50 50
EHA 29 7 13 1 / 10 30 50 50
LBL 29 13 13 5 / 0 10 50 50
HYS 28 9 17 5 / 0 20 10 30
P28 35 14 19 10 / 0 10 20 50
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Sugden
AVIATION...Gerard
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1025 PM MST TUE DEC 3 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 157 PM MST TUE DEC 3 2013
AS OF 3 PM CST...2 PM MST...SKIES ACROSS THE TRI-STATE AREA RANGED
FROM PARTLY CLOUDY TO OVERCAST AS HIGH CIRRUS CONTINUES TO PASS
OVER. TEMPERATURES REACHED THE LOW TO MID 60S ACROSS THE AREA WITH
THE EXCEPTION OF SOUTHWEST NEBRASKA. A BACK DOOR COLD FRONT HAS
MOVED IN FROM THE NORTHEAST...KEEPING THINGS ACROSS THE NORTHEASTERN
THIRD OF THE FORECAST AREA COOLER. WINDS HAVE BEEN FROM THE SOUTH
AHEAD OF THE COLD FRONT AND NORTHEAST BEHIND THE BACKDOOR FRONT. THE
MAIN COLD FRONT WAS FINALLY BEGINNING TO MAKE ITS SURGE INTO
NORTHEAST COLORADO. THE FRONT WAS BLOCKED BY A STRONG LEE TROUGH
CENTERED BETWEEN DENVER AND LIMON. THIS LEE TROUGH IS NOW STARTING
TO MOVE SOUTHEAST FROM LATEST RAP MSL ANALYSIS...ALLOWING THE MAIN
COLD FRONT TO SURGE SOUTH.
FOR THIS AFTERNOON AND TONIGHT...THE STRONG ARCTIC FRONT WILL MAKE
ITS PRESENCE FELT AS IT MOVES SOUTH. TEMPERATURES DROP RAPIDLY BY
THE FRONT AS SEEN BY THE 15 TO 20 DEGREE DROPS IN ONE HOUR AT YUMA
AND AKRON COLORADO. IMMEDIATELY BEHIND THE FRONT...GUSTY NORTH WINDS
ARE EXPECTED. WINDS NEAR WIND ADVISORY CRITERIA HAVE NOT BEEN
OBSERVED AND MODELS HAVE BACKED OFF ON WIND SPEEDS FROM YESTERDAYS
RUNS. THERE COULD BE SOME GUSTS THAT APPROACH WIND ADVISORY CRITERIA
BUT THIS SHOULD NOT BE WIDESPREAD NOR PERSISTENT. LOW TEMPERATURES
TONIGHT SHOULD BE ABLE TO DROP INTO THE LOW 10S TO LOW 20S EVEN WITH
DENSE CLOUD COVER. FOR PRECIPITATION CHANCES...MOST OF THE
PRECIPITATION WILL LIKELY HOLD OFF UNTIL AFTER 00Z WITH CHANCES
GRADUALLY INCREASING THROUGHOUT THE NIGHT. MODELS INDICATE THAT THE
ATMOSPHERE GRADUALLY SATURATES THROUGH THE NIGHT...ALLOWING SNOW TO
BEGIN FALLING THIS EVENING OR EARLY TOMORROW MORNING. SOUTHEAST
PORTIONS OF THE FORECAST AREA SHOULD MISS OUT ON THE PRECIPITATION
FOR THE MOST PART BUT COULD SEEM SOME FLURRIES. ACCUMULATIONS WILL
BE LIGHT AS ALL MODELS SHOW LIGHT QPF WITH HEAVIER AMOUNTS WEST
WHERE TERRAIN EFFECTS AND LIFT ARE STRONGER.
FOR TOMORROW...COLD WEATHER WILL CONTINUE WITH HIGH TEMPERATURES LESS
THAN 10 DEGREES WARMER THAN LOW TEMPERATURES TONIGHT. HIGHS ARE ONLY
ADVERTISED TO BE IN THE LOW 10S OVER NORTHEAST COLORADO TO THE MID
20S OUT NEAR HILL CITY. THIS COULD BE GENEROUS CONSIDERING THAT
DENSE CLOUD COVER AND NORTH WINDS SHOULD PERSIST. CHANCES FOR LIGHT
SNOW CONTINUE IN THE MORNING HOURS BEFORE CHANCES DECREASE ACROSS
NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. CHANCES SHOULD CONTINUE
OVER EAST COLORADO WITH A SLIGHT UPSLOPE COMPONENT AND A BETTER
ATMOSPHERIC MOISTURE PROFILE. AGAIN...ONLY LIGHT ACCUMULATIONS ARE
EXPECTED WITH LITTLE IMPACT TO TRAVEL. ANOTHER THING TO NOTE ABOUT
TOMORROW IS THAT WITH THE NORTH WINDS AND COLD TEMPERATURES...WIND
CHILLS SHOULD REMAIN IN THE SINGLE DIGITS ABOVE ZERO THROUGHOUT THE
DAY WITH BELOW ZERO WIND CHILLS POSSIBLE IN EAST COLORADO. NEEDLESS
TO SAY...TOMORROW WILL BE MUCH COLDER WITH HIGH TEMPERATURES ON THE
ORDER OF 20 TO 45 DEGREES COOLER DEPENDING ON THE LOCATION.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 157 PM MST TUE DEC 3 2013
COLD AIR WILL BE THOROUGHLY ENTRENCHED ACROSS THE CENTRAL HIGH
PLAINS REGION AND IS EXPECTED TO REMAIN IN PLACE THROUGH THE
FORECAST PERIOD. FLURRIES TO LIGHT SNOW WILL CONTINUE ACROSS
PORTIONS OF THE FORECAST AREA THROUGH THURSDAY NIGHT AS THE MAIN
UPPER TROUGH AND A COUPLE OF PRECEDING SHORT WAVE TROUGHS LIFT
OUT OF THE SOUTHWEST UNITED STATES AND ACROSS THE HIGH PLAINS REGION.
FRIDAY AND FRIDAY NIGHT WILL BE DRY AND COLD WITH HIGH PRESSURE IN
PLACE AT THE SURFACE IN THE WAKE OF THE UPPER TROUGH AS IT MOVES
QUICKLY TO THE EAST. LATE SATURDAY THROUGH SUNDAY BRINGS ANOTHER
CHANCE OF LIGHT SNOW AS THE NEXT UPPER LOW CENTER MOVES OUT OF THE
SOUTHWEST UNITED STATES AND INTO THE CENTRAL UNITED STATES.
MONDAY THROUGH TUESDAY WILL BE DRY AGAIN IN THE WAKE OF THE SECOND
UPPER SYSTEM WHILE COLD HIGH PRESSURE REMAINS IN PLACE...KEEPING
TEMPERATURES ABOUT 20 DEGREES COLDER THAN AVERAGE THROUGH THE
LONG TERM PORTION OF THE FORECAST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 941 PM MST TUE DEC 3 2013
MVFR CIGS CONTINUE AT KGLD AND KMCK AS HIGH PRESSURE BUILDS SOUTH
INTO THE CENTRAL PLAINS BEHIND THE COLD FRONT. METARS INDICATE
LIGHT SNOW OVER THE SOUTHERN NEBRASKA PANHANDLE. THE NAM MODEL
SHOWS SOME LIGHT SNOW POSSIBLE IN KGLD OVERNIGHT BUT THE FORECAST
SOUNDING DOES NOT SUPPORT SNOW UNTIL LATE WEDNESDAY AFTERNOON AND
EARLY EVENING. KMCK HAS EVEN LESS CHANCE FOR SNOW. DYNAMICS SHIFT
SOUTH WEDNESDAY EVENING WITH SOUNDING SHOWING IMPROVING CIGS TO
VFR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...RRH
LONG TERM...LOCKHART
AVIATION...FS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
817 PM CST Thu Dec 5 2013
.UPDATE...
ISSUED AT 815 PM CST THU DEC 5 2013
Currently making only minor adjustments to snow/sleet locations in
the grids. There are some slight differences between the latest
NAM and RAP soundings with the NAM a tad warmer. Will keep the mix
but move the snow line a bit farther south. Will up snow amounts
in some areas as Du Quoin is already measuring 2 inches.
Over SEMO now getting reports of sleet. CC product from radar
indicating a mix of snow with bursts of sleet. Expect that to
continue for a good portion of the night except for the extreme
southeast 3 or 4 counties where there might be more icing.
There is currently a lull over west Kentucky but we expect this to
fill in slowly as precipitation is increasing to our south. The
RAP and NAM models keeps a general lull over west Kentucky
through about 9z. Models seem to be hinting at the increase in
intensity over the entire area around midday tomorrow.
&&
.SHORT TERM...(This Evening through Saturday)
ISSUED AT 331 PM CST THU DEC 5 2013
The winter storm is a couple of hours earlier than expected, but
the overall evolution has been as expected so far. The
precipitation has quickly transitioned to sleet over much of
southeast Missouri and southern Illinois. Will allow the warning
to continue as is.
The main shift in guidance, led by the 12Z NAM is to hang onto a
very warm layer aloft longer into the event. The southeast corner
of the area may never see much in the way of snow before the
precipitation ends. The forecast has been shift a bit more toward
freezing rain/ice and less sleet and snow over much of west
Kentucky and Missouri Boot Heel region. A half inch of ice is
likely over much of this area, with just an inch or two of sleet
and snow. Over the northern portions of the area the 6-8" swath of
sleet and snow still looks good, and may not be high enough given
some sleet accumulations we have already received this afternoon.
The overall timing remains the same with the precipitation coming
to a rapid end from west to east Friday afternoon.
North winds generally 10 to 15 mph will continue to bring in much
cooler air through the short term period. Single digit temperatures
are expected over much of the area Friday night, and negative wind
chills are now forecast over much of the area Friday night as
well.
.LONG TERM...(Saturday Night through Thursday)
ISSUED AT 331 PM CST THU DEC 5 2013
Models continue to show low pressure over the western Gulf of Mexico
12z Sunday, with an inverted trof extending east of the PAH forecast
area. Models continue to trend a little farther east, which would
lessen amounts across our area. However, this will also keep our
region in colder air, thus indicating a more persistent wintry mix
and less potential for our southeast counties, where the highest QPF
should be, to change to rain on Sunday. Precipitation will spread
northwest across our counties late Saturday night and continue
through the day Sunday. Light amounts of snow, sleet and a little
freezing rain will be possible across southeast Missouri, southern
Illinois and southwest Indiana by the time the precipitation ends
late Sunday afternoon or Sunday evening.
Across west Kentucky, and possibly into extreme southeast Missouri
and extreme southern Illinois, more significant amounts of freezing
rain and sleet are possible. With almost all of the region below
freezing through the entire event, whatever falls will freeze and/or
accumulate. Southern portions of the Pennyrile region of west
Kentucky have the best chance for temperatures to climb above
freezing, but with the best QPF in this area, a tenth to a quarter
inch of ice accumulation will be possible before the temperatures
potentially climb to above freezing. Lesser amounts of ice are
expected across the rest of west Kentucky and adjacent areas.
Overall confidence is not very high right now, due to current models
trends, but fortunately amounts have trended downward from a couple
of days ago. If the GFS pans out, amounts would still be pretty
significant, but ECMWF, NAM and GEM all show higher QPF mainly over
portions of west Kentucky or to our east. Also, how much snow/ice
pack is left from the winter event just getting started across our
region will have an impact on temperatures and potential
accumulations. By late Sunday night the wintry precip, mainly snow
and sleet by that point, should gradually taper off from west to
east, with a return of dry conditions after 12z Monday.
High pressure will build across the Central Plains Monday and slowly
slide east through mid week, centered over the middle Mississippi
valley by 12z Wednesday. Very cold air will settle into our region
for the early part of the work week. Highs Monday will range from
the middle 20s north to the lower 30s south, then only in the 20s
area wide Tuesday. Lows both Monday night and Tuesday night will
range from the middle single digits north to the middle teens
southeast. By Wednesday and Thursday, with plenty of sunshine, high
temperatures will rebound a little, back into the middle 20s to
middle 30s.
&&
.AVIATION...
ISSUED AT 543 PM CST THU DEC 5 2013
MVFR cigs/vsbys should gradually deteriorate to IFR through the
period. FZRA/PL at KCGI/KEVV expected to continue through the night.
Changeover to snow should be around 15Z at KCGI and 18Z at KEVV.
At KPAH rain should change over to FZRA/PL by 02Z, then over to
snow around 17Z. At KOWB rain should change over to FZRA/PL around
05Z, then over to snow around 20Z. Northerly winds at 10-15 mph
gusting to 20-25 mph should continue through most of the period.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING until 6 PM CST Friday FOR ILZ075>078-
080>094.
MO...WINTER STORM WARNING until 6 PM CST Friday FOR MOZ076-086-087-
100-107>112-114.
IN...WINTER STORM WARNING until 6 PM CST Friday FOR INZ081-082-
085>088.
KY...WINTER STORM WARNING until 6 PM CST Friday FOR KYZ001>008-010-
011-013>016-018>020.
WINTER STORM WARNING from Midnight tonight to 9 PM CST Friday
FOR KYZ009-012-017-021-022.
&&
$$
UPDATE...PS
SHORT TERM...DRS
LONG TERM...RT
AVIATION...JP
AREA FORECAST DISCUSSION
NWS JACKSON KY
1259 PM EST WED DEC 4 2013
.UPDATE...
ISSUED AT 1100 AM EST WED DEC 4 2013
BASED ON LATEST TRENDS...INCLUDING A FEW MORE BREAKS IN THE
CLOUDS...HAVE INCREASED AFTERNOON MAXIMUM TEMPERATURES. WILL INCLUDE
SPRINKLES FOR THE START OF THE FORECAST PERIOD IN THE NORTH AND EAST.
HAVE UPDATED NDFD...WEB FORECASTS AND ZFP.
UPDATE ISSUED AT 853 AM EST WED DEC 4 2013
UPDATED NDFD...WEB FORECASTS AND ZFP TO INCLUDE ISOLATED SHOWERS THIS
MORNING ACROSS THE WESTERN AND CENTRAL PARTS OF THE FORECAST AREA.
THIS IS SUPPORTED BY CURRENT RADAR TRENDS AND LATEST HRRR GUIDANCE.
CURRENT EXPECTATIONS ARE FOR ISOLATED SHOWERS TO END BY EARLY AFTERNOON.
UPDATE ISSUED AT 651 AM EST WED DEC 4 2013
CLOUD COVER HAS PRETTY MUCH RETURNED ACROSS THE AREA AND SHOULD
PERSIST THROUGH A GOOD CHUNK OF THE DAY ONCE AGAIN AS A WARM FRONT
PUSHES NORTH TOWARDS THE AREA. SOME QUESTION AS TO IF THIS BOUNDARY
WILL CLEAR THE AREA BEFORE SUNSET. IF IT FAILS TO DO SO...CLOUD COVER
MAY HOLD FOR THE REMAINDER OF THE DAY. A FEW BREAKS CAN STILL BE
EXPECTED IN THE SOUTHEAST WITH DOWNSLOPING FLOW...BUT FOR THE MOST
PART...CLOUDY WILL BE THE WAY TO GO TODAY. COULD BE SOME VERY PATCHY
DRIZZLE OUT THERE THIS MORNING...BUT LIKELY CONFINED TO AREAS MORE
SOUTH AND WEST OF HERE. NO UPDATE PLANNED EARLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 308 AM EST WED DEC 4 2013
SATELLITE THIS MORNING REVEALS A STORM SYSTEM TAKING SHAPE OVER THE
NORTHERN PLAINS...WITH SOUTHERLY FLOW ACROSS THE MAJORITY OF THE
OHIO/TENNESSEE RIVER VALLEYS. WHILE WINDS REMAIN MOSTLY SOUTH...THERE
IS A SLIGHT EASTERLY COMPONENT TO THE WIND WHICH IS CONTINUING TO EAT
AWAY AT CLOUD COVER FROM TIME TO TIME OVER EASTERN KENTUCKY. THE
UNFAVORABLE DOWNSLOPING CONDITIONS WILL LIKELY BE OVERTAKEN THIS
MORNING AS A WARM FRONT LIFTS NORTH ACROSS THE AREA. THIS WILL YIELD
MOSTLY CLOUDY TO CLOUDY SKIES THROUGH A GOOD CHUNK OF THE DAY TODAY.
PREVIOUS THINKING WAS THE WARM FRONT WOULD SHOOT ON THROUGH...BUT NOW
LOOKS LIKE CLOUDS MAY HOLD OVER MUCH OF THE AREA THROUGH THE DAY.
THIS WILL LIKELY SUPPRESS TEMPERATURES. REGARDLESS...ADVECTION ALONE
SHOULD ALLOW TEMPERATURE TO CLIMB INTO THE LOW TO MID 60S. AREAS IN
THE SOUTHWEST HAVE A BETTER CHANCE OF CLEARING AND WE COULD SEE SOME
READINGS GETTING CLOSE TO 70. CLOUDS SHOULD CONTINUE ERODING INTO
TONIGHT...BUT SOUTHERLY WINDS ARE EXPECTED TO REMAIN IN TACT TONIGHT
WITH A GOOD GRADIENT. THIS WILL ALLOW OVERNIGHT LOWS TO REMAIN VERY
MILD WITH READINGS IN THE 50S (HIGHER THAN OUR AVERAGE HIGHS FOR THIS
TIME OF YEAR).
BY LATE TONIGHT...AND ESPECIALLY TOMORROW...ISENTROPIC ASCENT WILL
KICK INTO FULL GEAR WITH PRECIPITATION DEVELOPING ACROSS CENTRAL AND
EASTERN KENTUCKY. MODELS HAVE SLOWED DOWN THE ADVANCING COLD
FRONT...SO HAVE SLOWED DOWN PRECIPITATION CHANCES. IT DOES LOOK LIKE
PRECIPITATION SHOULD EASILY IMPACT THE I-75 CORRIDOR ON THURSDAY...BUT
RAIN MAY MAKE IT AS FAR AS FAR EASTERN KENTUCKY BY LATE IN THE DAY.
REGARDLESS...CONFIDENCE IS NOT AS HIGH IN THE EAST...SO HAVE GONE
WITH AN EAST TO WEST GRADIENT IN POPS. INITIAL RAINFALL TOTALS ON
THURSDAY ARE NOT EXPECTED TO BE TOO HIGH GIVEN THE INITIAL DRY AIR
TO OVERCOME. HOWEVER...SOME TOTALS NEAR A HALF INCH MAY BE POSSIBLE
NEAR THE I-75 CORRIDOR BY LATE IN THE DAY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 440 AM EST WED DEC 4 2013
EXCESSIVE RAINFALL STILL LOOKS ON TRACK THROUGH EARLY NEXT
WEEK...ALTHOUGH MODEL GUIDANCE HAS TRENDED A BIT LEANER WITH THE
FIRST BATCH OF RAINFALL...WITH 2 TO 2.5 INCHES OF RAIN SUGGESTED
NOW...AND THEN SIMILAR TOTALS OCCURRING FROM SUNDAY THROUGH MONDAY.
THIS WOULD YIELD 4 DAY TOTALS IN THE 4 TO 5 INCH RANGE...WITH LARGER
CREEKS...STREAMS...AND RIVERS SEEING THE BEST CHANCE OF FLOODING
GIVEN THE LONG DURATION OF THE PRECIPITATION. WILL CONTINUE TO
HIGHLIGHT THESE CONCERNS IN AN ONGOING HYDROLOGIC OUTLOOK.
THE COLD FRONT WILL HAVE SETTLED JUST OFF TO THE SOUTHEAST OF OUR
AREA THURSDAY NIGHT. IT WILL CONTINUE TO SAG SOUTHEAST AND PIVOT A
BIT MORE AS SURFACE WAVES TRAVERSE THE BOUNDARY. THE RAIN MAY FALL
HEAVY AT TIMES THURSDAY NIGHT AND PARTICULARLY FRIDAY AS THE
STRONGEST UPPER LEVEL JET MOVES THROUGH THE GREAT LAKES AND LEAVES
MUCH OF THE OHIO VALLEY IN A FAVORABLE RIGHT ENTRANCE REGION.
SOME LIGHT SLUSHY ACCUMULATION STILL LOOKS LIKE A POSSIBILITY
GENERALLY ALONG AND NORTH OF THE MOUNTAIN PARKWAY. THE COLD AIR
ADVECTION HAS TRENDED A BIT QUICKER...SO THERE MAY BE A 1 TO 2 HOUR
WINDOW OF DECENT ENOUGH SNOWFALL RATES TO OVERCOME THE WARM GROUND
TEMPERATURES TEMPORARILY HEADING INTO DUSK. WILL AWAIT FURTHER MODEL
CONSISTENCY BEFORE DRAWING MORE ATTENTION TO THIS POTENTIAL AS IMPACT
OVERALL STILL LOOKS ON THE LOW SIDE.
PRECIPITATION WILL TAPER OFF QUICKLY FRIDAY NIGHT FROM NORTHWEST TO
SOUTHEAST AS COLDER AND MUCH DRIER AIR ADVECT IN FROM HIGH PRESSURE
SETTLING IN ACROSS THE PLAINS. DRY AND MUCH COLDER WEATHER IS
EXPECTED FOR SATURDAY...WITH HIGHS RANGING FROM THE LOWER 30S NORTH
OF I-64...TO THE LOWER 40S BORDERING TENNESSEE.
THE NEXT PRECIPITATION EVENT WILL THEN THREATEN EASTERN KENTUCKY BY
SATURDAY NIGHT...AS AN INVERTED SURFACE TROUGH BECOMES RE-ESTABLISHED
ACROSS THE LOWER MISSISSIPPI VALLEY. THE PRECIPITATION WILL BEGIN AS
SNOW ESPECIALLY NORTH OF THE HAL ROGERS PARKWAY AND HIGHWAY 80
CORRIDORS...HOWEVER THE WARM NOSE LOOKS TO OVERWHELM THE COLD AIR
QUICKLY...SO IT LOOKS TO BE ANOTHER MORE LIMITED WINDOW OF SNOW AND
POSSIBLY AN ALTERNATIVE TYPE OF PRECIPITATION DEPENDING ON HOW COLD
IT CAN GET SATURDAY NIGHT AND THE FURTHER EVOLUTION OF THE SYSTEM.
EXPECT A TRANSITION TO ALL RAIN THROUGH SUNDAY...AS A MORE ROBUST
SURFACE WAVE DEVELOPS ALONG THE BOUNDARY IN THE GULF AND HEADS
NORTHEAST. THIS SURFACE LOW WILL CONTINUE TO DEEPEN AS IT HEADS INTO
THE GREAT LAKES BY MONDAY. THE HEAVIEST RAIN LOOKS TO FALL ACROSS
EASTERN KENTUCKY SUNDAY NIGHT INTO MONDAY AS UPPER LEVEL DYNAMICS ARE
MAXIMIZED ONCE AGAIN ACROSS THE OHIO VALLEY. MUCH COLDER AIR WILL
MOVE IN BEHIND THE COLD FRONT...ONCE IT GETS DRAGGED TOWARDS THE
EASTERN SEABOARD LATE MONDAY. EXPECT SOME BACKSIDE SNOW ONCE
AGAIN...HOWEVER WITH DEEPER MOISTURE EXITING...AM ONLY SEEING LIGHT
ACCUMULATIONS RIGHT NOW. TUESDAY HIGHS WILL STRUGGLE TO REACH THE
FREEZING MARK AT MOST LOCATIONS...WITH DRY WEATHER RETURNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1259 PM EST WED DEC 4 2013
BROKEN TO OVERCAST SKIES WITH MAINLY VFR CEILINGS..AND SOME PATCHY
MVFR CEILINGS WILL PERSIST ACROSS THE REGION THROUGH THE DAY. A WARM
FRONT WILL LIFT NORTH ACROSS THE REGION THIS AFTERNOON...WITH SOME
GUSTY SOUTH WINDS EXPECTED AT LOZ AND SME. AFTER THE WARM FRONT
PASSES NORTH...WARM MOIST AIR WILL CONTINUE TO SPREAD INTO THE
FORECAST AREA WITH CEILINGS EXPECTED TO LOWER TO MVFR LATE TONIGHT
AND EARLY THURSDAY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST ON
THURSDAY...WITH RAIN CHANCES INCREASING FROM THE AFTERNOON INTO THE
NIGHT. STILL POSSIBLE SOME LOW LEVEL WIND SHEAR COULD DEVELOP TONIGHT
AND THIS WILL NEED TO BE MONITORED.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...KAS
LONG TERM...GEOGERIAN
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
1100 AM EST WED DEC 4 2013
.UPDATE...
ISSUED AT 1100 AM EST WED DEC 4 2013
BASED ON LATEST TRENDS...INCLUDING A FEW MORE BREAKS IN THE
CLOUDS...HAVE INCREASED AFTERNOON MAXIMUM TEMPERATURES. WILL INCLUDE
SPRINKLES FOR THE START OF THE FORECAST PERIOD IN THE NORTH AND EAST.
HAVE UPDATED NDFD...WEB FORECASTS AND ZFP.
UPDATE ISSUED AT 853 AM EST WED DEC 4 2013
UPDATED NDFD...WEB FORECASTS AND ZFP TO INCLUDE ISOLATED SHOWERS THIS
MORNING ACROSS THE WESTERN AND CENTRAL PARTS OF THE FORECAST AREA.
THIS IS SUPPORTED BY CURRENT RADAR TRENDS AND LATEST HRRR GUIDANCE.
CURRENT EXPECTATIONS ARE FOR ISOLATED SHOWERS TO END BY EARLY AFTERNOON.
UPDATE ISSUED AT 651 AM EST WED DEC 4 2013
CLOUD COVER HAS PRETTY MUCH RETURNED ACROSS THE AREA AND SHOULD
PERSIST THROUGH A GOOD CHUNK OF THE DAY ONCE AGAIN AS A WARM FRONT
PUSHES NORTH TOWARDS THE AREA. SOME QUESTION AS TO IF THIS BOUNDARY
WILL CLEAR THE AREA BEFORE SUNSET. IF IT FAILS TO DO SO...CLOUD COVER
MAY HOLD FOR THE REMAINDER OF THE DAY. A FEW BREAKS CAN STILL BE
EXPECTED IN THE SOUTHEAST WITH DOWNSLOPING FLOW...BUT FOR THE MOST
PART...CLOUDY WILL BE THE WAY TO GO TODAY. COULD BE SOME VERY PATCHY
DRIZZLE OUT THERE THIS MORNING...BUT LIKELY CONFINED TO AREAS MORE
SOUTH AND WEST OF HERE. NO UPDATE PLANNED EARLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 308 AM EST WED DEC 4 2013
SATELLITE THIS MORNING REVEALS A STORM SYSTEM TAKING SHAPE OVER THE
NORTHERN PLAINS...WITH SOUTHERLY FLOW ACROSS THE MAJORITY OF THE
OHIO/TENNESSEE RIVER VALLEYS. WHILE WINDS REMAIN MOSTLY SOUTH...THERE
IS A SLIGHT EASTERLY COMPONENT TO THE WIND WHICH IS CONTINUING TO EAT
AWAY AT CLOUD COVER FROM TIME TO TIME OVER EASTERN KENTUCKY. THE
UNFAVORABLE DOWNSLOPING CONDITIONS WILL LIKELY BE OVERTAKEN THIS
MORNING AS A WARM FRONT LIFTS NORTH ACROSS THE AREA. THIS WILL YIELD
MOSTLY CLOUDY TO CLOUDY SKIES THROUGH A GOOD CHUNK OF THE DAY TODAY.
PREVIOUS THINKING WAS THE WARM FRONT WOULD SHOOT ON THROUGH...BUT NOW
LOOKS LIKE CLOUDS MAY HOLD OVER MUCH OF THE AREA THROUGH THE DAY.
THIS WILL LIKELY SUPPRESS TEMPERATURES. REGARDLESS...ADVECTION ALONE
SHOULD ALLOW TEMPERATURE TO CLIMB INTO THE LOW TO MID 60S. AREAS IN
THE SOUTHWEST HAVE A BETTER CHANCE OF CLEARING AND WE COULD SEE SOME
READINGS GETTING CLOSE TO 70. CLOUDS SHOULD CONTINUE ERODING INTO
TONIGHT...BUT SOUTHERLY WINDS ARE EXPECTED TO REMAIN IN TACT TONIGHT
WITH A GOOD GRADIENT. THIS WILL ALLOW OVERNIGHT LOWS TO REMAIN VERY
MILD WITH READINGS IN THE 50S (HIGHER THAN OUR AVERAGE HIGHS FOR THIS
TIME OF YEAR).
BY LATE TONIGHT...AND ESPECIALLY TOMORROW...ISENTROPIC ASCENT WILL
KICK INTO FULL GEAR WITH PRECIPITATION DEVELOPING ACROSS CENTRAL AND
EASTERN KENTUCKY. MODELS HAVE SLOWED DOWN THE ADVANCING COLD
FRONT...SO HAVE SLOWED DOWN PRECIPITATION CHANCES. IT DOES LOOK LIKE
PRECIPITATION SHOULD EASILY IMPACT THE I-75 CORRIDOR ON THURSDAY...BUT
RAIN MAY MAKE IT AS FAR AS FAR EASTERN KENTUCKY BY LATE IN THE DAY.
REGARDLESS...CONFIDENCE IS NOT AS HIGH IN THE EAST...SO HAVE GONE
WITH AN EAST TO WEST GRADIENT IN POPS. INITIAL RAINFALL TOTALS ON
THURSDAY ARE NOT EXPECTED TO BE TOO HIGH GIVEN THE INITIAL DRY AIR
TO OVERCOME. HOWEVER...SOME TOTALS NEAR A HALF INCH MAY BE POSSIBLE
NEAR THE I-75 CORRIDOR BY LATE IN THE DAY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 440 AM EST WED DEC 4 2013
EXCESSIVE RAINFALL STILL LOOKS ON TRACK THROUGH EARLY NEXT
WEEK...ALTHOUGH MODEL GUIDANCE HAS TRENDED A BIT LEANER WITH THE
FIRST BATCH OF RAINFALL...WITH 2 TO 2.5 INCHES OF RAIN SUGGESTED
NOW...AND THEN SIMILAR TOTALS OCCURRING FROM SUNDAY THROUGH MONDAY.
THIS WOULD YIELD 4 DAY TOTALS IN THE 4 TO 5 INCH RANGE...WITH LARGER
CREEKS...STREAMS...AND RIVERS SEEING THE BEST CHANCE OF FLOODING
GIVEN THE LONG DURATION OF THE PRECIPITATION. WILL CONTINUE TO
HIGHLIGHT THESE CONCERNS IN AN ONGOING HYDROLOGIC OUTLOOK.
THE COLD FRONT WILL HAVE SETTLED JUST OFF TO THE SOUTHEAST OF OUR
AREA THURSDAY NIGHT. IT WILL CONTINUE TO SAG SOUTHEAST AND PIVOT A
BIT MORE AS SURFACE WAVES TRAVERSE THE BOUNDARY. THE RAIN MAY FALL
HEAVY AT TIMES THURSDAY NIGHT AND PARTICULARLY FRIDAY AS THE
STRONGEST UPPER LEVEL JET MOVES THROUGH THE GREAT LAKES AND LEAVES
MUCH OF THE OHIO VALLEY IN A FAVORABLE RIGHT ENTRANCE REGION.
SOME LIGHT SLUSHY ACCUMULATION STILL LOOKS LIKE A POSSIBILITY
GENERALLY ALONG AND NORTH OF THE MOUNTAIN PARKWAY. THE COLD AIR
ADVECTION HAS TRENDED A BIT QUICKER...SO THERE MAY BE A 1 TO 2 HOUR
WINDOW OF DECENT ENOUGH SNOWFALL RATES TO OVERCOME THE WARM GROUND
TEMPERATURES TEMPORARILY HEADING INTO DUSK. WILL AWAIT FURTHER MODEL
CONSISTENCY BEFORE DRAWING MORE ATTENTION TO THIS POTENTIAL AS IMPACT
OVERALL STILL LOOKS ON THE LOW SIDE.
PRECIPITATION WILL TAPER OFF QUICKLY FRIDAY NIGHT FROM NORTHWEST TO
SOUTHEAST AS COLDER AND MUCH DRIER AIR ADVECT IN FROM HIGH PRESSURE
SETTLING IN ACROSS THE PLAINS. DRY AND MUCH COLDER WEATHER IS
EXPECTED FOR SATURDAY...WITH HIGHS RANGING FROM THE LOWER 30S NORTH
OF I-64...TO THE LOWER 40S BORDERING TENNESSEE.
THE NEXT PRECIPITATION EVENT WILL THEN THREATEN EASTERN KENTUCKY BY
SATURDAY NIGHT...AS AN INVERTED SURFACE TROUGH BECOMES RE-ESTABLISHED
ACROSS THE LOWER MISSISSIPPI VALLEY. THE PRECIPITATION WILL BEGIN AS
SNOW ESPECIALLY NORTH OF THE HAL ROGERS PARKWAY AND HIGHWAY 80
CORRIDORS...HOWEVER THE WARM NOSE LOOKS TO OVERWHELM THE COLD AIR
QUICKLY...SO IT LOOKS TO BE ANOTHER MORE LIMITED WINDOW OF SNOW AND
POSSIBLY AN ALTERNATIVE TYPE OF PRECIPITATION DEPENDING ON HOW COLD
IT CAN GET SATURDAY NIGHT AND THE FURTHER EVOLUTION OF THE SYSTEM.
EXPECT A TRANSITION TO ALL RAIN THROUGH SUNDAY...AS A MORE ROBUST
SURFACE WAVE DEVELOPS ALONG THE BOUNDARY IN THE GULF AND HEADS
NORTHEAST. THIS SURFACE LOW WILL CONTINUE TO DEEPEN AS IT HEADS INTO
THE GREAT LAKES BY MONDAY. THE HEAVIEST RAIN LOOKS TO FALL ACROSS
EASTERN KENTUCKY SUNDAY NIGHT INTO MONDAY AS UPPER LEVEL DYNAMICS ARE
MAXIMIZED ONCE AGAIN ACROSS THE OHIO VALLEY. MUCH COLDER AIR WILL
MOVE IN BEHIND THE COLD FRONT...ONCE IT GETS DRAGGED TOWARDS THE
EASTERN SEABOARD LATE MONDAY. EXPECT SOME BACKSIDE SNOW ONCE
AGAIN...HOWEVER WITH DEEPER MOISTURE EXITING...AM ONLY SEEING LIGHT
ACCUMULATIONS RIGHT NOW. TUESDAY HIGHS WILL STRUGGLE TO REACH THE
FREEZING MARK AT MOST LOCATIONS...WITH DRY WEATHER RETURNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 651 AM EST WED DEC 4 2013
MVFR CIGS WILL CONTINUE THROUGH MUCH OF THE MORNING BEFORE LIFTING
BACK TO VFR THIS AFTERNOON. WITH THE WARM FRONT PUNCHING THROUGH THE
AREA LATE IN THE DAY...CLOUDS SHOULD GIVE WAY TO ONLY SOME MID/HIGH
CLOUDS FOR THE OVERNIGHT HOURS. A COLD FRONT WILL PUSH TOWARDS THE
AREA BY LATE IN THE PERIOD...BUT CLOUDS SHOULD REMAIN VFR THROUGH
18Z. THE POSSIBILITY OF SOME LOW LEVEL WIND SHEAR WILL BEGIN BY LATE
IN THE DAY CONTINUING THROUGH TONIGHT...BUT NOT CONFIDENT ON HOW
MIXED THE SURFACE WILL BE TO INCLUDE IN THE TAF AT THE MOMENT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...KAS
LONG TERM...GEOGERIAN
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
854 AM EST WED DEC 4 2013
.UPDATE...
ISSUED AT 853 AM EST WED DEC 4 2013
UPDATED NDFD...WEB FORECASTS AND ZFP TO INCLUDE ISOLATED SHOWERS THIS
MORNING ACROSS THE WESTERN AND CENTRAL PARTS OF THE FORECAST AREA.
THIS IS SUPPORTED BY CURRENT RADAR TRENDS AND LATEST HRRR GUIDANCE.
CURRENT EXPECTATIONS ARE FOR ISOLATED SHOWERS TO END BY EARLY AFTERNOON.
UPDATE ISSUED AT 651 AM EST WED DEC 4 2013
CLOUD COVER HAS PRETTY MUCH RETURNED ACROSS THE AREA AND SHOULD
PERSIST THROUGH A GOOD CHUNK OF THE DAY ONCE AGAIN AS A WARM FRONT
PUSHES NORTH TOWARDS THE AREA. SOME QUESTION AS TO IF THIS BOUNDARY
WILL CLEAR THE AREA BEFORE SUNSET. IF IT FAILS TO DO SO...CLOUD COVER
MAY HOLD FOR THE REMAINDER OF THE DAY. A FEW BREAKS CAN STILL BE
EXPECTED IN THE SOUTHEAST WITH DOWNSLOPING FLOW...BUT FOR THE MOST
PART...CLOUDY WILL BE THE WAY TO GO TODAY. COULD BE SOME VERY PATCHY
DRIZZLE OUT THERE THIS MORNING...BUT LIKELY CONFINED TO AREAS MORE
SOUTH AND WEST OF HERE. NO UPDATE PLANNED EARLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 308 AM EST WED DEC 4 2013
SATELLITE THIS MORNING REVEALS A STORM SYSTEM TAKING SHAPE OVER THE
NORTHERN PLAINS...WITH SOUTHERLY FLOW ACROSS THE MAJORITY OF THE
OHIO/TENNESSEE RIVER VALLEYS. WHILE WINDS REMAIN MOSTLY SOUTH...THERE
IS A SLIGHT EASTERLY COMPONENT TO THE WIND WHICH IS CONTINUING TO EAT
AWAY AT CLOUD COVER FROM TIME TO TIME OVER EASTERN KENTUCKY. THE
UNFAVORABLE DOWNSLOPING CONDITIONS WILL LIKELY BE OVERTAKEN THIS
MORNING AS A WARM FRONT LIFTS NORTH ACROSS THE AREA. THIS WILL YIELD
MOSTLY CLOUDY TO CLOUDY SKIES THROUGH A GOOD CHUNK OF THE DAY TODAY.
PREVIOUS THINKING WAS THE WARM FRONT WOULD SHOOT ON THROUGH...BUT NOW
LOOKS LIKE CLOUDS MAY HOLD OVER MUCH OF THE AREA THROUGH THE DAY.
THIS WILL LIKELY SUPPRESS TEMPERATURES. REGARDLESS...ADVECTION ALONE
SHOULD ALLOW TEMPERATURE TO CLIMB INTO THE LOW TO MID 60S. AREAS IN
THE SOUTHWEST HAVE A BETTER CHANCE OF CLEARING AND WE COULD SEE SOME
READINGS GETTING CLOSE TO 70. CLOUDS SHOULD CONTINUE ERODING INTO
TONIGHT...BUT SOUTHERLY WINDS ARE EXPECTED TO REMAIN IN TACT TONIGHT
WITH A GOOD GRADIENT. THIS WILL ALLOW OVERNIGHT LOWS TO REMAIN VERY
MILD WITH READINGS IN THE 50S (HIGHER THAN OUR AVERAGE HIGHS FOR THIS
TIME OF YEAR).
BY LATE TONIGHT...AND ESPECIALLY TOMORROW...ISENTROPIC ASCENT WILL
KICK INTO FULL GEAR WITH PRECIPITATION DEVELOPING ACROSS CENTRAL AND
EASTERN KENTUCKY. MODELS HAVE SLOWED DOWN THE ADVANCING COLD
FRONT...SO HAVE SLOWED DOWN PRECIPITATION CHANCES. IT DOES LOOK LIKE
PRECIPITATION SHOULD EASILY IMPACT THE I-75 CORRIDOR ON THURSDAY...BUT
RAIN MAY MAKE IT AS FAR AS FAR EASTERN KENTUCKY BY LATE IN THE DAY.
REGARDLESS...CONFIDENCE IS NOT AS HIGH IN THE EAST...SO HAVE GONE
WITH AN EAST TO WEST GRADIENT IN POPS. INITIAL RAINFALL TOTALS ON
THURSDAY ARE NOT EXPECTED TO BE TOO HIGH GIVEN THE INITIAL DRY AIR
TO OVERCOME. HOWEVER...SOME TOTALS NEAR A HALF INCH MAY BE POSSIBLE
NEAR THE I-75 CORRIDOR BY LATE IN THE DAY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 440 AM EST WED DEC 4 2013
EXCESSIVE RAINFALL STILL LOOKS ON TRACK THROUGH EARLY NEXT
WEEK...ALTHOUGH MODEL GUIDANCE HAS TRENDED A BIT LEANER WITH THE
FIRST BATCH OF RAINFALL...WITH 2 TO 2.5 INCHES OF RAIN SUGGESTED
NOW...AND THEN SIMILAR TOTALS OCCURRING FROM SUNDAY THROUGH MONDAY.
THIS WOULD YIELD 4 DAY TOTALS IN THE 4 TO 5 INCH RANGE...WITH LARGER
CREEKS...STREAMS...AND RIVERS SEEING THE BEST CHANCE OF FLOODING
GIVEN THE LONG DURATION OF THE PRECIPITATION. WILL CONTINUE TO
HIGHLIGHT THESE CONCERNS IN AN ONGOING HYDROLOGIC OUTLOOK.
THE COLD FRONT WILL HAVE SETTLED JUST OFF TO THE SOUTHEAST OF OUR
AREA THURSDAY NIGHT. IT WILL CONTINUE TO SAG SOUTHEAST AND PIVOT A
BIT MORE AS SURFACE WAVES TRAVERSE THE BOUNDARY. THE RAIN MAY FALL
HEAVY AT TIMES THURSDAY NIGHT AND PARTICULARLY FRIDAY AS THE
STRONGEST UPPER LEVEL JET MOVES THROUGH THE GREAT LAKES AND LEAVES
MUCH OF THE OHIO VALLEY IN A FAVORABLE RIGHT ENTRANCE REGION.
SOME LIGHT SLUSHY ACCUMULATION STILL LOOKS LIKE A POSSIBILITY
GENERALLY ALONG AND NORTH OF THE MOUNTAIN PARKWAY. THE COLD AIR
ADVECTION HAS TRENDED A BIT QUICKER...SO THERE MAY BE A 1 TO 2 HOUR
WINDOW OF DECENT ENOUGH SNOWFALL RATES TO OVERCOME THE WARM GROUND
TEMPERATURES TEMPORARILY HEADING INTO DUSK. WILL AWAIT FURTHER MODEL
CONSISTENCY BEFORE DRAWING MORE ATTENTION TO THIS POTENTIAL AS IMPACT
OVERALL STILL LOOKS ON THE LOW SIDE.
PRECIPITATION WILL TAPER OFF QUICKLY FRIDAY NIGHT FROM NORTHWEST TO
SOUTHEAST AS COLDER AND MUCH DRIER AIR ADVECT IN FROM HIGH PRESSURE
SETTLING IN ACROSS THE PLAINS. DRY AND MUCH COLDER WEATHER IS
EXPECTED FOR SATURDAY...WITH HIGHS RANGING FROM THE LOWER 30S NORTH
OF I-64...TO THE LOWER 40S BORDERING TENNESSEE.
THE NEXT PRECIPITATION EVENT WILL THEN THREATEN EASTERN KENTUCKY BY
SATURDAY NIGHT...AS AN INVERTED SURFACE TROUGH BECOMES RE-ESTABLISHED
ACROSS THE LOWER MISSISSIPPI VALLEY. THE PRECIPITATION WILL BEGIN AS
SNOW ESPECIALLY NORTH OF THE HAL ROGERS PARKWAY AND HIGHWAY 80
CORRIDORS...HOWEVER THE WARM NOSE LOOKS TO OVERWHELM THE COLD AIR
QUICKLY...SO IT LOOKS TO BE ANOTHER MORE LIMITED WINDOW OF SNOW AND
POSSIBLY AN ALTERNATIVE TYPE OF PRECIPITATION DEPENDING ON HOW COLD
IT CAN GET SATURDAY NIGHT AND THE FURTHER EVOLUTION OF THE SYSTEM.
EXPECT A TRANSITION TO ALL RAIN THROUGH SUNDAY...AS A MORE ROBUST
SURFACE WAVE DEVELOPS ALONG THE BOUNDARY IN THE GULF AND HEADS
NORTHEAST. THIS SURFACE LOW WILL CONTINUE TO DEEPEN AS IT HEADS INTO
THE GREAT LAKES BY MONDAY. THE HEAVIEST RAIN LOOKS TO FALL ACROSS
EASTERN KENTUCKY SUNDAY NIGHT INTO MONDAY AS UPPER LEVEL DYNAMICS ARE
MAXIMIZED ONCE AGAIN ACROSS THE OHIO VALLEY. MUCH COLDER AIR WILL
MOVE IN BEHIND THE COLD FRONT...ONCE IT GETS DRAGGED TOWARDS THE
EASTERN SEABOARD LATE MONDAY. EXPECT SOME BACKSIDE SNOW ONCE
AGAIN...HOWEVER WITH DEEPER MOISTURE EXITING...AM ONLY SEEING LIGHT
ACCUMULATIONS RIGHT NOW. TUESDAY HIGHS WILL STRUGGLE TO REACH THE
FREEZING MARK AT MOST LOCATIONS...WITH DRY WEATHER RETURNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 651 AM EST WED DEC 4 2013
MVFR CIGS WILL CONTINUE THROUGH MUCH OF THE MORNING BEFORE LIFTING
BACK TO VFR THIS AFTERNOON. WITH THE WARM FRONT PUNCHING THROUGH THE
AREA LATE IN THE DAY...CLOUDS SHOULD GIVE WAY TO ONLY SOME MID/HIGH
CLOUDS FOR THE OVERNIGHT HOURS. A COLD FRONT WILL PUSH TOWARDS THE
AREA BY LATE IN THE PERIOD...BUT CLOUDS SHOULD REMAIN VFR THROUGH
18Z. THE POSSIBILITY OF SOME LOW LEVEL WIND SHEAR WILL BEGIN BY LATE
IN THE DAY CONTINUING THROUGH TONIGHT...BUT NOT CONFIDENT ON HOW
MIXED THE SURFACE WILL BE TO INCLUDE IN THE TAF AT THE MOMENT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...KAS
LONG TERM...GEOGERIAN
AVIATION...KAS
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
1018 PM EST THU DEC 5 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE THROUGH THE AREA THROUGH FRIDAY
MORNING. HIGH PRESSURE WILL BUILD OVERHEAD SATURDAY. LOW PRESSURE
WILL IMPACT THE AREA SUNDAY INTO MONDAY. CANADIAN HIGH PRESSURE
WILL RETURN FOR THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
SFC COLD FRONT IS LOCATED OVER THE APPALACHIANS AT 9 PM. SLY FLOW
IN PRE-FRONTAL WARM SECTOR HAS YIELDED A VERY MILD NIGHT FOR DEC.
CURRENT TEMPS ACROSS THE CWA RANGE FROM THE MID 50S TO THE MID
60S. THE COLD FRONT WILL MOVE THRU THE POTOMAC HIGHLANDS LATE THIS
EVE...AND GRADUALLY PUSH SEWD TOWARD I-95 AROUND DAWN. NLY WINDS
WILL BE ACCOMPANIED BY A DROP IN TEMPS BEHIND THE FRONT WHILE
TEMPS WILL REMAIN MILD AHEAD OF THE FRONT. MIN TEMP FCST IS TRICKY
IN THIS SETUP AS IT IS HIGHLY DEPENDENT ON THE POSITION OF THE
FRONT BY MRNG.
ADJUSTED POPS BASED OFF RECENT RADAR TRENDS AND HRRR GUIDANCE...
WHICH HAD ACCURATELY CAPTURED THE RECENT WEAKENING TREND OF PRECIP
AHEAD OF THE FRONT AS THIS ACTIVITY CROSS THE MTS. SHOWERS THIS EVE
WILL BE VERY LIGHT AND INTERMITTENT. PRECIP SHOULD ALSO BE LGT
OVNGT BUT HIGHER IN COVERAGE WHEN THE FROPA MOVES THRU.
THE COLD FRONT WILL SAG SWD INTO CENTRAL VA/SRN MD IN THE MRNG AND
SRN VA BY THE AFTN. FCST TEMPS DO NOT FOLLOW A DIURNAL CURVE WITH
CAA OCCURRING IN POST-FRONTAL SECTOR. THEREFORE...HIGHS WILL LIKELY
OCCUR AROUND MIDNIGHT BEFORE DROPPING IMMEDIATELY BEHIND THE FRONT
AND REMAINING STEADY IN THE AFTN. THE ANA-FRONTAL STRUCTURE OF THIS
SYSTEM WILL TRANSLATE TO A WET DAY ON FRI. MODELS CONTINUE TO SHOW
THE BEST FORCING ALONG AND ON THE COLD SIDE OF THE H8 BAROCLINIC
ZONE. MODELS ARE IN GOOD AGREEMENT WITH THE AXIS OF HEAVIER AND
STEADIER PRECIP CLOSER TOWARD THE MASON-DIXON LINE AND ALLEGHENY
FRONT. QPF AMOUNTS THRU FRI AFTN RANGE FROM LESS THAN A QUARTER INCH
S/E OF I-95 TO JUST UNDER AN INCH ALONG THE ALLEGHENY FRONT.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
THE COLD FRONT - WHICH WL BE CAUGHT UP IN THE SW-NE RUNNING
JET...WL SLOWLY SLIDE THRU THE MID ATLC FRI NGT. FRI NGT WL BE
WET...BUT P-TYPE WL BE LIQUID OUTSIDE OF THE HIGHER ELEVS. PCPN WL
BE EXITING THE RGN BY SAT MRNG. FCST SNOWFALL ACCUMULATIONS ALONG
THE ALLEGHENY FRONT ARE UNDER AN INCH. TEMPS WL RANGE FM THE 20S
IN THE HIGHLANDS TO THE L40S ALONG THE BAY...30S ELSEWHERE.
SAT WL DFNTLY BE THE NICER DAY OF THE WKND AS HIGH PRES MOVES OVER
THE RGN. HIGHS IN THE 30S AND L40S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
SUNDAY`S MET PATTERN IS COMPLEX. THE HIGH WHICH WAS OVR THE RGN
SAT WL BE TRACKING NE OVR LONG ISLAND. AT SAME TIME LOW PRES IS
PROGGED TO FORM ON THE TAIL END OF THE BNDRY WHICH CAME THRU FRI
NGT. THIS IS GOING TO PLACE THE MID ALTC RGN IN THE CLASSIC CAD
SITUATION W/ ISOTHERMS/ISOBARS KINKING DOWN THE ERN SIDE OF THE
APLCHNS.
PCPN LKLY TO BEGIN SUN MRNG AS A PD OF SNOW...BCMG A WINTRY MIX
BY SUN AFTN. WE ARE STILL 3 DAYS OUT...SO I AM HESITANT TO TRY TO
PIN DOWN EXACTLY WHAT I THINK WL HAPPEN...BUT FZRA/IP ARE XPCTD W
OF I-95 SUN AFTN/EVE. ALONG THE BAY THE WATER TEMP IS STILL IN THE
L40S...W/ ERLY FLOW BLV PCPN CLOSE TO THE WATER WL BE RA SUN AFTN.
IN THE CITIES/ALONG I-95 COULD BE RA OR ZR DEPENDING ON THE
ATMOSPHERIC TEMP PROFILE. IN THE MAJOR CITIES TEMPS WL PRBLY BE
CLOSE TO FRZG...SO EVEN IF P-TYPE IS FZRA ACCUMULATING FZRA WL
PRBLY BE DIFFICULT. W OF I-95 COULD A DIFFERENT STORY...BUT THERE
ARE STILL MULTIPLE MDL RUNS TO COME IN OVR THE NEXT 48-60 HRS.
ADJUSTMENTS WL LKLY HV TO BE MADE TO THIS FCST.
CSTL LOW XPCTD TO DVLP NEAR ORF SUN NGT...KEEPING THE MID ATLC
WET. THE CAD PATTERN IS ALSO XPCTD TO CONT...WHICH WOULD LEAD TO
PROLONGING THE WINTRY WX. A MIX IS XPCTD. LOWS IN THE L30S XCPT
WARMER ALONG BAY.
HIGH PRES FINALLY BLDS BACK INTO THE RGN TUE...BUT THIS WL LKLY
LEAD TO A BRZY/WINDY DAY.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
PERIODS OF LGT RAIN ARE EXPECTED THRU THE NGT AS A COLD FRONT
MOVES THRU THE TERMINALS. EXPECT FROPA TO OCCUR FROM WEST TO EAST
BETWEEN OVNGT AT MRB AND ERY TO MID FRI MRNG FARTHER SOUTH AND
EAST. SLY WINDS AND MAINLY MVFR VSBYS AHEAD OF THE FRONT BECOME
NWLY WITH CIGS LOWERING TO BORDERLINE MVFR-IFR BEHIND THE FRONT.
MORE WIDESPREAD RAIN WILL ENTER THE REGION FRIDAY AS LOW PRESSURE
FORMS ALONG THE FRONTAL BOUNDARY. LOW CONFIDENCE IN CIGS IMPROVING
TO MVFR/VFR DUE TO THE SLOW NATURE OF THE FRONT AND DEVELOPING LOW
PRESSURE.
FRI NGT RA/LOW CIGS/FOG PSBL AT ALL TAF SITES...THEN IMPRVG SAT AS
HIGH PRES BLDS OVR THE RGN. SUN/SUN NGT COULD BE POOR AT ALL TAF
SITES AS LOW CIGS/POOR VSBY/WINTRY PCPN XPCTD. HIGH PRES FINALLY
BUILDS BACK INTO THE MID ATLC TUE....WHICH SHOULD CREATE GUSTY W WINDS.
&&
.MARINE...
SLY CHANNELING IN THE MAIN STEM OF THE CHSPK BAY HAVE PRODUCED
WIND GUSTS AROUND 15 KT. DELAYED ONSET OF SCA ELSEHWERE UNTIL LATE
TNGT. A WARM AIRMASS ATOP COLD WATER DOES NOT PRODUCE A FAVORABLE
SETUP FOR MIXING...SO AM ON THE FENCE OF CANCELLING SCA FOR AREAS
THAT ARE NOT PRONE TO SLY CHANNELING.
SCA ISSUED FOR LATE FRI NGT AS A COLD FRONT MOVES SOUTH OF THE
WATERS AND THE PRESSURE GRADIENT INCREASES. NLY GUSTS 20-25 KT WILL
ACCOMPANY THIS PRESSURE SURGE. SCA WILL LIKELY NEED TO BE EXTENDED
INTO SAT.
WINDS MAY DECREASE SUNDAY AS HIGH PRESSURE PASSES TO OUR NORTH...THEN
INCREASE TO AT LEAST MARGINAL CONDITIONS AGAIN MONDAY AS A COLD
FRONT APPROACHES. A MORE SIGNIFICANT SCA...PSBLY GALE IS PSBL TUE
AS HIGH PRES BLDS BACK INTO THE WATERS.
&&
.HYDROLOGY...
AN UNSETTLED WEATHER PERIOD IS IN STORE FOR THE MID-ATLANTIC REGION.
FORECAST RAINFALL AMOUNTS THRU FRI NGT ARE LOWER THAN PREVIOUSLY
EXPECTED...GENERALLY ON THE ORDER OF 0.50-1 INCH...WHICH CREATES
ONLY MINOR RISES IN RIVERS.
MORE PRECIPITATION IS PROJECTED OVER THE REGION SUNDAY INTO
MONDAY...AND THIS WILL LIKELY BE HEAVIER THAN THE FIRST ROUND.
NAEFS AND GEFS MEAN RAINFALL FOR BOTH EVENTS COMBINED IS BETWEEN
TWO AND THREE INCHES. WHILE THE LATEST MODELS HAVE BACKED OFF ON
QPF AND RIVER STAGE FORECASTS A BIT...THERE IS STILL A POTENTIAL
FOR SOME FLOODING ISSUES ON ON BOTH SMALL STREAMS AND ON THE
MAINSTEM RIVERS SUNDAY THROUGH EARLY NEXT WEEK. IF FROZEN PRECIP
FALLS...THE MELTING OF IT FACTORS INTO THE EQUATION TOO. THERE IS
STILL A GREAT DEAL OF UNCERTAINTY REGARDING WHERE THE HEAVIEST
PRECIPITATION SETS UP...AND WHETHER IT STAYS IN ONE PLACE FOR A
WHILE.
&&
.TIDES/COASTAL FLOODING...
ANOMALIES REMAIN STEADY AROUND 3/4 FOOT ABOVE. NO COASTAL FLOODING
IS EXPECTED TNGT. WINDS WILL SHIFT TO THE NORTH BEHIND A COLD
FRONT ON FRIDAY INTO FRIDAY NIGHT. WATERS LEVELS WILL GRADUALLY
DECREASE DURING THIS TIME. HAVE REMOVED THREAT OF COASTAL FLOODING
OUT OF THE HWO.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR ANZ531>534-537-
539>541-543.
SMALL CRAFT ADVISORY FROM MIDNIGHT FRIDAY NIGHT TO 6 AM EST
SATURDAY FOR ANZ530>543.
SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR ANZ530-535-536-
538-542.
&&
$$
UPDATE...JRK
PREV DISC...JRK/HAS/WOODY!
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
954 PM EST THU DEC 5 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE INTO THE AREA TONIGHT AND FRIDAY MORNING.
HIGH PRESSURE WILL BUILD OVERHEAD SATURDAY. LOW PRESSURE WILL
IMPACT THE AREA SUNDAY INTO MONDAY. CANADIAN HIGH PRESSURE WILL
RETURN FOR THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
SFC COLD FRONT IS LOCATED OVER THE APPALACHIANS. SLY FLOW IN
PRE-FRONTAL WARM SECTOR HAS YIELDED A VERY MILD NIGHT FOR DEC. TEMPS
AT 9 PM ACROSS THE CWA RANGE FROM THE MID 50S TO THE MID 60S. THE
COLD FRONT WILL MOVE THRU THE POTOMAC HIGHLANDS LATE THIS EVE...AND
GRADUALLY PUSH SEWD TOWARD I-95 TOWARD DAWN. NW WINDS WILL BE
ACCOMPANIED BY A DROP IN TEMPS BEHIND THE FRONT WHILE TEMPS WILL
REMAIN MILD AHEAD OF THE FRONT. MIN TEMP FCST IS TRICKY IN THE SETUP
AS IT IS HIGHLY DEPENDENT ON THE POSITION OF THE FRONT BY MRNG.
ADJUSTED POPS BASED OFF RECENT RADAR TRENDS AND HRRR GUIDANCE...
WHICH HAD ACCURATELY CAPTURED THE RECENT WEAKENING TREND OF PRECIP
AHEAD OF THE FRONT AS THIS ACTIVITY CROSS THE MTS. SHOWERS THIS EVE
WILL BE VERY LIGHT AND INTERMITTENT. PRECIP SHOULD MAINLY BE LGT
OVNGT BUT HIGHER IN COVERAGE WHEN THE FROPA MOVES THRU.
THE COLD FRONT WILL SAG SWD INTO CENTRAL VA/SRN MD IN THE MRNG AND
SRN VA BY THE AFTN. FCST TEMPS DO NOT FOLLOW A DIURNAL CURVE WITH
CAA OCCURRING IN POST-FRONTAL SECTOR. THEREFORE...HIGHS WILL LIKELY
OCCUR AROUND MIDNIGHT BEFORE DROPPING IMMEDIATELY BEHIND THE FRONT
AND REMAINING STEADY IN THE AFTN. THE ANA-FRONTAL STRUCTURE OF THIS
SYSTEM WILL TRANSLATE TO A WET DAY ON FRI. MODELS CONTINUE TO SHOW
THE BEST FORCING ALONG AND ON THE COLD SIDE OF THE H8 BAROCLINIC
ZONE. MODELS ARE IN GOOD AGREEMENT WITH THE AXIS OF HEAVIER AND
STEADIER PRECIP CLOSER TOWARD THE MASON-DIXON LINE AND ALLEGHENY
FRONT. QPF AMOUNTS THRU FRI AFTN RANGE FROM LESS THAN A QUARTER INCH
S/E OF I-95 TO JUST UNDER AN INCH ALONG THE ALLEGHENY FRONT.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
THE COLD FRONT - WHICH WL BE CAUGHT UP IN THE SW-NE RUNNING
JET...WL SLOWLY SLIDE THRU THE MID ATLC FRI NGT. FRI NGT WL BE
WET...BUT P-TYPE WL BE LIQUID OUTSIDE OF THE HIGHER ELEVS. PCPN WL
BE EXITING THE RGN BY SAT MRNG. FCST SNOWFALL ACCUMULATIONS ALONG
THE ALLEGHENY FRONT ARE UNDER AN INCH. TEMPS WL RANGE FM THE 20S
IN THE HIGHLANDS TO THE L40S ALONG THE BAY...30S ELSEWHERE.
SAT WL DFNTLY BE THE NICER DAY OF THE WKND AS HIGH PRES MOVES OVER
THE RGN. HIGHS IN THE 30S AND L40S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
SUNDAY`S MET PATTERN IS COMPLEX. THE HIGH WHICH WAS OVR THE RGN
SAT WL BE TRACKING NE OVR LONG ISLAND. AT SAME TIME LOW PRES IS
PROGGED TO FORM ON THE TAIL END OF THE BNDRY WHICH CAME THRU FRI
NGT. THIS IS GOING TO PLACE THE MID ALTC RGN IN THE CLASSIC CAD
SITUATION W/ ISOTHERMS/ISOBARS KINKING DOWN THE ERN SIDE OF THE
APLCHNS.
PCPN LKLY TO BEGIN SUN MRNG AS A PD OF SNOW...BCMG A WINTRY MIX
BY SUN AFTN. WE ARE STILL 3 DAYS OUT...SO I AM HESITANT TO TRY TO
PIN DOWN EXACTLY WHAT I THINK WL HAPPEN...BUT FZRA/IP ARE XPCTD W
OF I-95 SUN AFTN/EVE. ALONG THE BAY THE WATER TEMP IS STILL IN THE
L40S...W/ ERLY FLOW BLV PCPN CLOSE TO THE WATER WL BE RA SUN AFTN.
IN THE CITIES/ALONG I-95 COULD BE RA OR ZR DEPENDING ON THE
ATMOSPHERIC TEMP PROFILE. IN THE MAJOR CITIES TEMPS WL PRBLY BE
CLOSE TO FRZG...SO EVEN IF P-TYPE IS FZRA ACCUMULATING FZRA WL
PRBLY BE DIFFICULT. W OF I-95 COULD A DIFFERENT STORY...BUT THERE
ARE STILL MULTIPLE MDL RUNS TO COME IN OVR THE NEXT 48-60 HRS.
ADJUSTMENTS WL LKLY HV TO BE MADE TO THIS FCST.
CSTL LOW XPCTD TO DVLP NEAR ORF SUN NGT...KEEPING THE MID ATLC
WET. THE CAD PATTERN IS ALSO XPCTD TO CONT...WHICH WOULD LEAD TO
PROLONGING THE WINTRY WX. A MIX IS XPCTD. LOWS IN THE L30S XCPT
WARMER ALONG BAY.
HIGH PRES FINALLY BLDS BACK INTO THE RGN TUE...BUT THIS WL LKLY
LEAD TO A BRZY/WINDY DAY.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
PERIODS OF LGT RAIN ARE EXPECTED THRU THE NGT AS A COLD FRONT
MOVES THRU THE TERMINALS. EXPECT FROPA TO OCCUR FROM WEST TO EAST
BETWEEN OVNGT AT MRB AND ERY TO MID FRI MRNG FARTHER SOUTH AND
EAST. SLY WINDS AND MAINLY MVFR VSBYS AHEAD OF THE FRONT BECOME
NWLY WITH CIGS LOWERING TO BORDERLINE MVFR-IFR BEHIND THE FRONT.
MORE WIDESPREAD RAIN WILL ENTER THE REGION FRIDAY AS LOW PRESSURE
FORMS ALONG THE FRONTAL BOUNDARY. LOW CONFIDENCE IN CIGS IMPROVING
TO MVFR/VFR DUE TO THE SLOW NATURE OF THE FRONT AND DEVELOPING LOW
PRESSURE.
FRI NGT RA/LOW CIGS/FOG PSBL AT ALL TAF SITES...THEN IMPRVG SAT AS
HIGH PRES BLDS OVR THE RGN. SUN/SUN NGT COULD BE POOR AT ALL TAF
SITES AS LOW CIGS/POOR VSBY/WINTRY PCPN XPCTD. HIGH PRES FINALLY
BUILDS BACK INTO THE MID ATLC TUE....WHICH SHOULD CREATE GUSTY W WINDS.
&&
.MARINE...
SLY CHANNELING IN THE MAIN STEM OF THE CHSPK BAY HAVE PRODUCED
WIND GUSTS AROUND 15 KT. DELAYED ONSET OF SCA ELSEHWERE UNTIL LATE
TNGT. A WARM AIRMASS ATOP COLD WATER DOES NOT PRODUCE A FAVORABLE
SETUP FOR MIXING...SO AM ON THE FENCE OF CANCELLING SCA FOR AREAS
THAT ARE NOT PRONE TO SLY CHANNELING.
SCA ISSUED FOR LATE FRI NGT AS A COLD FRONT MOVES SOUTH OF THE
WATERS AND THE PRESSURE GRADIENT INCREASES. NLY GUSTS 20-25 KT WILL
ACCOMPANY THIS PRESSURE SURGE. SCA WILL LIKELY NEED TO BE EXTENDED
INTO SAT.
WINDS MAY DECREASE SUNDAY AS HIGH PRESSURE PASSES TO OUR NORTH...THEN
INCREASE TO AT LEAST MARGINAL CONDITIONS AGAIN MONDAY AS A COLD
FRONT APPROACHES. A MORE SIGNIFICANT SCA...PSBLY GALE IS PSBL TUE
AS HIGH PRES BLDS BACK INTO THE WATERS.
&&
.HYDROLOGY...
AN UNSETTLED WEATHER PERIOD IS IN STORE FOR THE MID-ATLANTIC REGION.
FORECAST RAINFALL AMOUNTS THRU FRI NGT ARE LOWER THAN PREVIOUSLY
EXPECTED...GENERALLY ON THE ORDER OF 0.50-1 INCH...WHICH CREATES
ONLY MINOR RISES IN RIVERS.
HOWEVER...MORE PRECIPITATION IS PROJECTED OVER THE REGION SUNDAY
INTO MONDAY...AND THIS WILL LIKELY BE HEAVIER THAN THE FIRST ROUND.
GFS ENSEMBLE MEAN RAINFALL FOR BOTH EVENTS COMBINED IS CLOSE TO
THREE INCHES...WITH SOME MEMBERS SHOWING OVER 4 INCHES. GIVEN
LITTLE RECOVERY TIME IN BETWEEN EVENTS...THIS AMOUNT OF
RAINFALL...IF IT OCCURS...COULD BE SUFFICIENT TO GENERATE FLOODING
ON BOTH SMALL STREAMS AND ON THE MAINSTEM RIVERS SUNDAY THROUGH
EARLY NEXT WEEK. IF FROZEN PRECIP FALLS...THE MELTING OF IT FACTORS
INTO THE EQUATION TOO. THERE IS STILL A GREAT DEAL OF UNCERTAINTY
REGARDING WHERE THE HEAVIEST PRECIPITATION SETS UP...AND WHETHER IT
STAYS IN ONE PLACE FOR A WHILE. THIS SITUATION WILL CONTINUE TO BE
MONITORED IN THE DAYS AHEAD.
&&
.TIDES/COASTAL FLOODING...
ANOMALIES REMAIN STEADY AROUND 3/4 FOOT ABOVE. NO COASTAL FLOODING
IS EXPECTED TNGT...AND WINDS WILL SHIFT TO THE NORTHWEST BEHIND A
COLD FRONT LATER FRIDAY THROUGH FRIDAY NIGHT. WATERS LEVELS WILL
DECREASE DURING THIS TIME. HAVE REMOVED THREAT OF COASTAL FLOODING
OUT OF THE HWO.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR ANZ531>534-537-
539>541-543.
SMALL CRAFT ADVISORY FROM MIDNIGHT FRIDAY NIGHT TO 6 AM EST
SATURDAY FOR ANZ530>543.
SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR ANZ530-535-536-
538-542.
&&
$$
UPDATE...JRK
PREV FCST...HAS/WOODY!
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
457 PM EST WED DEC 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 400 PM EST WED DEC 4 2013
20Z SFC CHART INDICATES ELONGATED SFC TROUGH FROM WCNTRL WI INTO
NORTHEAST IA WITH MSLP OF 998MB. WV AND RUC FCST SHOWS SHORTWAVE
PUSHING ACROSS SOUTHERN MINNESOTA. WAVE IS EXPECTED TO LIFT TOWARD
NORTHWEST WI WHILE DEEPENING OVERNIGHT. WARM AIR ADVECTION IN FULL
SWING AHEAD OF MAINLY 850MB LOW LIFTING INTO NW WISCONSIN. RUC13 AND
NAM12 HAVE DONE NICE JOB WITH THE WARM LAYER AT H9-H85 TODAY AND
BOTH SHOW H85 TEMPS OVER 2C REACHING NORTH OF ALL CWA BY 00Z.
SOUNDINGS OVER US CURRENTLY WOULD SUGGEST MAINLY FZRA BUT LINGERING
COLD POCKET NEAR SFC /TEMPS STILL IN MID-UPR 20S/ IS ALLOWING SLEET
TO HANG ON LONGER. CURRENTLY SNOW IS STILL FALLING OVER KEWEENAW
PENINSULA BUT IS EVEN STARTING TO MIX WITH FREEZING RAIN AND SLEET
OVER PORTIONS OF WESTERN UPR MICHIGAN. PLAN FOR EVENING IS THAT
MIXED FREEZING RAIN/SLEET/SNOW WILL CHANGE TO MAINLY FREEZING RAIN
AND SLEET WHILE MOSTLY FREEZING RAIN OR EVEN JUST RAIN OCCURS FOR
CNTRL CWA...ESPECIALLY CLOSER TO LK MICHIGAN SHORE. IF HEAVIER
PRECIP WAS EXPECTED OVR CNTRL THIS EVENING...ICING COULD BE BIGGER
ISSUE. RIGHT NOW...APPEARS THAT HEAVIER PRECIP IS GOING TO OCCUR IN
STRIPE FROM SOUTHERN MINNESOTA TOWARD WESTERN LK SUPERIOR IN AREAS
OF STRONGEST PVA/DIVERGENCE ALOFT JUST AHEAD OF TRACK OF SHORTWAVE.
GIVEN TREND TO MORE FZRA THOUGH...INCREASED ICE ACCUMS OVER INTERIOR
WEST AND CNTRL TO 0.10-0.20 INCHES THROUGH THE EVENING.
AS MID-LEVEL DRYING IN THE H7-H6 LAYER ARRIVES 03Z-06Z OVER THE
SOUTH AND AFTER 06Z IN THE NORTH...EXPECT WINTRY MIX OF PRECIP TO
TAPER OFF TO MORE OF A DRIZZLE/FREEZING DRIZZLE. ACTUALLY HEADLINES
SO FAR ARE WORKING OUT PRETTY WELL. DID HAVE TO GO WITH MORE SLEET
AND FREEZING RAIN AS WARM AIR WORKED IN QUICKER...BUT OVERALL IDEA
OF WINTRY MIX IS COVERED WITH GOING WINTER WEATHER ADVY. TIMING FOR
ENDING OF ADVY SEEMS GOOD AS WELL. ONLY POSSIBLE TROUBLE SPOTS WILL
IN THE INTERIOR CNTRL AND EAST THIS EVENING DUE TO ICING IF HEAVIER
PRECIP ENDS UP BLOSSOMING TO THE EAST OF PRIMARY SHORTWAVE. SOME
SHORT TERM HIGHER-RES MODELS INDICATE EXPANSION OF PRECIP OVER
SCNTRL THIS EVENING...BUT RADAR TRENDS UPSTREAM NOT REALLY SHOWING
THIS. IF SFC TEMPS STAY BLO FREEZING THAT AREA WILL NEED TO BE
WATCHED FOR POSSIBLE ADVY.
NOW ONTO LATE TONIGHT AND THURSDAY. MAIN ISSUE SEEMS TO BE LK EFFECT
AND BLOWING SNOW ON THE KEWEENAW. WEST WINDS MAY GUST OVER 40 MPH AT
TIMES LEADING TO THE BLSN/POOR VISIBILITY...PROBABLY 1/4-1/2SM AT
TIMES OVER PORTIONS OF THE KEWEENAW. LARGER SCALE FORCING BECOMES
NEGATIVE BUT THERE IS A LOT OF LINGERING MOISTURE BLO H8 WITH
COOLING AT INVERSION TOP TO -16C OR SO BY MIDDAY. GIVEN LK SUPERIOR
WATER TEMPS AROUND 3-4C THIS GIVES MORE THAN SUFFICIENT OVER-WATER
INSTABILITY FOR AT LEAST MODERATE LK EFFECT SNOW SHOWERS. WSW WINDS
OVER LAND WITH MORE OF A WESTERLY WIND OVER LK SUPERIOR INDICATES
STRONGER CONVERGENCE AREA SETS UP ACROSS KEWEENAW. SNOW AMOUNTS WILL
BE HELD DOWN SOME BY LOWER SLR/S AS THERE IS A LOT OF FRACTURING OF
SNOWFLAKES DUE TO THE STRONG WINDS. EXPECT ADVY LEVEL SNOWS OF 3-5"
OR 4-7" WITH A LOT OF WIND/BLSN. WILL ISSUE A SEPARATE LAKE EFFECT
SNOW ADVY FOR LATE TONIGHT THROUGH THURSDAY...GOING INTO PLACE RIGHT
WHEN THE CURRENT WINTER WEATHER ADVY FOR THE MESSY MIX OF SNOW/SLEET
AND FREEZING RAIN DIMINISHES.
AND FINALLY FOR LATE TONIGHT INTO THURSDAY...AWAY FM THE
KEWEENAW...MAIN ISSUE WILL BE COLD AIR PUSHING IN FM THE WEST.
ALREADY SEEING THIS ARCTIC AIR POURING ACROSS THE DAKOTAS THIS AFTN.
EXPECT SLOWLY FALLING TEMPERATURES THROUGH THE DAY AS THE COLD WORKS
EAST...WITH READINGS LIKELY INTO THE UPPER SINGLE DIGITS BY EVENING
OVER THE FAR WEST CWA. THIS COLDER AIR WILL ALSO FREEZE ANY
LINGERING SLUSH AND WATER IS ON THE ROADS AND SIDEWALKS...WHICH
COULD RESULT IN TOUGHER TRAVEL CONDITIONS IN SPOTS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 456 PM EST WED DEC 4 2013
THE EASY PART OF THIS FCST PERIOD WILL BE THE LACK OF MIXED
PRECIPITATION. EXPECT ONLY SNOW...WITH SFC TEMPS MAXING OUT IN THE
LOW TO MID 20F DEGREE RANGE /MONDAY/ AND 850MB TEMPS TOPPING OUT
AROUND -15C EAST EARLY THURSDAY NIGHT...AND AGAIN SUNDAY THROUGH
MONDAY AROUND -12 TO -15C.
WILL CONTINUE TO HAVE LES OVER THE W HALF OF UPPER MI THURSDAY
NIGHT. AMOUNTS ARE STILL IN QUESTION. MAY NEED TO EXTEND THE CURRENT
LES ADVISORY FOR ANOTHER 6-12HRS IF THE 3-5IN OF SNOW FALL OVER
KEWEENAW...N HOUGHTON...AND FAR W ONTONAGON COUNTY THURSDAY NIGHT.
THE LES PARAMETER OFF THE GFS REMAINS AT OR ABOVE 2 THROUGH 06Z
FRIDAY. WILL LET LATER SHIFTS DISCUSS THE NEED...AS THE WINDS
DIMINISH SIGNIFICANTLY...BUT STILL GUSTING TO AROUND 20-25KTS
OVERNIGHT. THE WEAKENING SFC TROUGH WILL LINGER ACROSS THE UPPER
GREAT LAKES THROUGH SATURDAY...WITH WINDS SLOWLY MOVING MORE
OFFSHORE SATURDAY NIGHT. UNTIL THEN...LES WILL LINGER MAINLY ACROSS
THE KEWEENAW PENINSULA.
KEPT MENTION OF THE COLDEST TEMPS OF THE SEASON IN THE HWO FOR
THURSDAY NIGHT THROUGH SATURDAY MORNING. AT THIS POINT IT LOOKS LIKE
A WIND CHILL ADVISORY MAY NOT BE NEEDED FOR FRIDAY NIGHT INTO
SATURDAY MORNING...AS THE LOWEST VALUES FLIRT WITH -25C OVER THE SW
CORNER OF THE CWA.
STRONG SFC HIGH OVER SW CANADA FRIDAY WILL PUSH ACROSS THE NORTHERN
AND CENTRAL PLAINS FRIDAY NIGHT INTO EARLY SATURDAY...BEFORE
BUILDING ACROSS THE GREAT LAKES REGION. ENDED UP SPLITTING UP SOME
OF THE MORE EXTENDED POPS AS A RESULT...FOR SATURDAY THROUGH SUNDAY.
THE NEXT ROUND OF SNOW WILL SLIDE BACK IN SUNDAY NIGHT...WITH LIKELY
POPS OVER THE E HALF...AS THE HIGH EXITS ACROSS THE NEW ENGLAND
STATES AND LOW PRESSURE NEARS FROM THE LOWER AND CENTRAL MS VALLEY.
THE SFC LOW LOOKS TO CROSS LAKE HURON AROUND 12Z MONDAY...DEEPENING
AS IT MOVES TO S QUEBEC MONDAY AFTERNOON/EVENING. THIS WILL BRING
ABOUT ANOTHER ROUND OF W TO NW WINDS...WITH GALES AGAIN POSSIBLE
ACROSS LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1234 PM EST WED DEC 4 2013
A LOW PRESSURE SYSTEM WILL KEEP PRECIP AT THE TAF SITES INTO
TONIGHT. WARM AIR MOVING INTO THE REGION WILL SWITCH SNOW THIS
MORNING TO RAIN AND FREEZING RAIN AT TIMES INTO EARLY TONIGHT...MOST
LIKELY AT SAW AND MORE LIKELY TO STAY A WINTRY MIX AT IWD AND CMX.
LOTS OF DIFFICULTY FORECASTING EXACT CHANGE OVER TIMES...SO PUT BEST
GUESS INTO TAFS. PRECIP WILL CHANGE BACK TO SNOW TONIGHT AS COLD AIR
COMES IN BEHIND A COLD FRONT...WHILE PRECIP TRANSITIONS FROM AREA
WIDE PRECIP TO LAKE EFFECT SNOW...FAVORING IWD AND ESPECIALLY CMX
INTO THURSDAY. USED CONSENSUS GUIDANCE FOR CIGS/VIS AND MORE
CLIMATOLOGY FOR LAKE EFFECT SNOW LATE IN THE PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 317 PM EST WED DEC 4 2013
LOW PRESSURE OVER WISCONSIN WILL DEEPEN ACROSS CENTRAL AND EASTERN
LAKE SUPERIOR OVERNIGHT...AND EXIT NORTHEAST ACROSS JAMES BAY WHILE
FURTHER DEEPENING THURSDAY NIGHT. THE PERIOD OF STRONG WINDS WILL
CONTINUE THROUGH THURSDAY NIGHT...WITH OUR INITIAL E TO NE WINDS
/GALES TO 35KTS OVER W LAKE SUPERIOR/ BECOMING OUT OF THE S AND SW
FOR ALL BUT FAR W LAKE SUPERIOR OVERNIGHT...BEFORE W GALES OF 35 TO
40 KNOTS START UP THURSDAY MORNING THROUGH THURSDAY NIGHT.
A STRONG ARCTIC HIGH PRESSURE SYSTEM OVER WESTERN CANADA ON THURSDAY
WILL SLIDE ACROSS THE NORTHERN PLAINS ON SATURDAY...AND ACROSS THE
GREAT LAKES SUNDAY. THE HIGH WILL EXIT ACROSS THE NEW ENGLAND STATES
WHILE WEAKENING SLIGHTLY ON MONDAY. EXPECT LOW PRESSURE OVER THE
LOWER MISSISSIPPI VALLEY SUNDAY TO DEEPEN AND SURGE NORTHWARD ACROSS
LAKE HURON LATE SUNDAY NIGHT INTO MONDAY. W TO NW GALES TO 35KTS
WILL BE POSSIBLE AGAIN MONDAY THROUGH TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ THURSDAY
FOR MIZ002-004-005-009>011-084.
LAKE EFFECT SNOW ADVISORY FROM 4 AM TO 7 PM EST THURSDAY FOR
MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 4 AM EST THURSDAY FOR MIZ001-003.
LAKE SUPERIOR...
GALE WARNING FROM 6 AM THURSDAY TO 4 AM EST FRIDAY FOR
LSZ265>267.
GALE WARNING UNTIL 4 AM EST FRIDAY FOR LSZ263-264.
GALE WARNING FROM 8 AM TO 7 PM EST THURSDAY FOR LSZ246>248-250-
251.
GALE WARNING FROM 5 AM EST /4 AM CST/ TO 7 PM EST /6 PM CST/
THURSDAY FOR LSZ241>245.
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THURSDAY FOR LSZ162.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...KF
AVIATION...TITUS
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
401 PM EST WED DEC 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 400 PM EST WED DEC 4 2013
20Z SFC CHART INDICATES ELONGATED SFC TROUGH FROM WCNTRL WI INTO
NORTHEAST IA WITH MSLP OF 998MB. WV AND RUC FCST SHOWS SHORTWAVE
PUSHING ACROSS SOUTHERN MINNESOTA. WAVE IS EXPECTED TO LIFT TOWARD
NORTHWEST WI WHILE DEEPENING OVERNIGHT. WARM AIR ADVECTION IN FULL
SWING AHEAD OF MAINLY 850MB LOW LIFTING INTO NW WISCONSIN. RUC13 AND
NAM12 HAVE DONE NICE JOB WITH THE WARM LAYER AT H9-H85 TODAY AND
BOTH SHOW H85 TEMPS OVER 2C REACHING NORTH OF ALL CWA BY 00Z.
SOUNDINGS OVER US CURRENTLY WOULD SUGGEST MAINLY FZRA BUT LINGERING
COLD POCKET NEAR SFC /TEMPS STILL IN MID-UPR 20S/ IS ALLOWING SLEET
TO HANG ON LONGER. CURRENTLY SNOW IS STILL FALLING OVER KEWEENAW
PENINSULA BUT IS EVEN STARTING TO MIX WITH FREEZING RAIN AND SLEET
OVER PORTIONS OF WESTERN UPR MICHIGAN. PLAN FOR EVENING IS THAT
MIXED FREEZING RAIN/SLEET/SNOW WILL CHANGE TO MAINLY FREEZING RAIN
AND SLEET WHILE MOSTLY FREEZING RAIN OR EVEN JUST RAIN OCCURS FOR
CNTRL CWA...ESPECIALLY CLOSER TO LK MICHIGAN SHORE. IF HEAVIER
PRECIP WAS EXPECTED OVR CNTRL THIS EVENING...ICING COULD BE BIGGER
ISSUE. RIGHT NOW...APPEARS THAT HEAVIER PRECIP IS GOING TO OCCUR IN
STRIPE FROM SOUTHERN MINNESOTA TOWARD WESTERN LK SUPERIOR IN AREAS
OF STRONGEST PVA/DIVERGENCE ALOFT JUST AHEAD OF TRACK OF SHORTWAVE.
GIVEN TREND TO MORE FZRA THOUGH...INCREASED ICE ACCUMS OVER INTERIOR
WEST AND CNTRL TO 0.10-0.20 INCHES THROUGH THE EVENING.
AS MID-LEVEL DRYING IN THE H7-H6 LAYER ARRIVES 03Z-06Z OVER THE
SOUTH AND AFTER 06Z IN THE NORTH...EXPECT WINTRY MIX OF PRECIP TO
TAPER OFF TO MORE OF A DRIZZLE/FREEZING DRIZZLE. ACTUALLY HEADLINES
SO FAR ARE WORKING OUT PRETTY WELL. DID HAVE TO GO WITH MORE SLEET
AND FREEZING RAIN AS WARM AIR WORKED IN QUICKER...BUT OVERALL IDEA
OF WINTRY MIX IS COVERED WITH GOING WINTER WEATHER ADVY. TIMING FOR
ENDING OF ADVY SEEMS GOOD AS WELL. ONLY POSSIBLE TROUBLE SPOTS WILL
IN THE INTERIOR CNTRL AND EAST THIS EVENING DUE TO ICING IF HEAVIER
PRECIP ENDS UP BLOSSOMING TO THE EAST OF PRIMARY SHORTWAVE. SOME
SHORT TERM HIGHER-RES MODELS INDICATE EXPANSION OF PRECIP OVER
SCNTRL THIS EVENING...BUT RADAR TRENDS UPSTREAM NOT REALLY SHOWING
THIS. IF SFC TEMPS STAY BLO FREEZING THAT AREA WILL NEED TO BE
WATCHED FOR POSSIBLE ADVY.
NOW ONTO LATE TONIGHT AND THURSDAY. MAIN ISSUE SEEMS TO BE LK EFFECT
AND BLOWING SNOW ON THE KEWEENAW. WEST WINDS MAY GUST OVER 40 MPH AT
TIMES LEADING TO THE BLSN/POOR VISIBILITY...PROBABLY 1/4-1/2SM AT
TIMES OVER PORTIONS OF THE KEWEENAW. LARGER SCALE FORCING BECOMES
NEGATIVE BUT THERE IS A LOT OF LINGERING MOISTURE BLO H8 WITH
COOLING AT INVERSION TOP TO -16C OR SO BY MIDDAY. GIVEN LK SUPERIOR
WATER TEMPS AROUND 3-4C THIS GIVES MORE THAN SUFFICIENT OVER-WATER
INSTABILITY FOR AT LEAST MODERATE LK EFFECT SNOW SHOWERS. WSW WINDS
OVER LAND WITH MORE OF A WESTERLY WIND OVER LK SUPERIOR INDICATES
STRONGER CONVERGENCE AREA SETS UP ACROSS KEWEENAW. SNOW AMOUNTS WILL
BE HELD DOWN SOME BY LOWER SLR/S AS THERE IS A LOT OF FRACTURING OF
SNOWFLAKES DUE TO THE STRONG WINDS. EXPECT ADVY LEVEL SNOWS OF 3-5"
OR 4-7" WITH A LOT OF WIND/BLSN. WILL ISSUE A SEPARATE LAKE EFFECT
SNOW ADVY FOR LATE TONIGHT THROUGH THURSDAY...GOING INTO PLACE RIGHT
WHEN THE CURRENT WINTER WEATHER ADVY FOR THE MESSY MIX OF SNOW/SLEET
AND FREEZING RAIN DIMINISHES.
AND FINALLY FOR LATE TONIGHT INTO THURSDAY...AWAY FM THE
KEWEENAW...MAIN ISSUE WILL BE COLD AIR PUSHING IN FM THE WEST.
ALREADY SEEING THIS ARCTIC AIR POURING ACROSS THE DAKOTAS THIS AFTN.
EXPECT SLOWLY FALLING TEMPERATURES THROUGH THE DAY AS THE COLD WORKS
EAST...WITH READINGS LIKELY INTO THE UPPER SINGLE DIGITS BY EVENING
OVER THE FAR WEST CWA. THIS COLDER AIR WILL ALSO FREEZE ANY
LINGERING SLUSH AND WATER IS ON THE ROADS AND SIDEWALKS...WHICH
COULD RESULT IN TOUGHER TRAVEL CONDITIONS IN SPOTS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 507 AM EST WED DEC 4 2013
MAIN FCST CONCERNS IN THE LONG TERM INCLUDE TEMPS/LES MAINLY IN THE
W-NW SN BELTS AND THE POTENTIAL FOR ANOTHER LARGER SCALE SN EVENT
EARLY NEXT WEEK. OVERALL TEMPS WL RUN WELL BLO NORMAL MOST OF THE
LONGER TERM WITH ARCTIC HI PRES DOMINATING. THE COLDEST AIRMASS OF
THE SEASON IS LIKELY TO INVADE THE UPR LKS IN THE WAKE OF THE LO
PRES SYSTEM THAT MIGHT BRING THE WDSPRD SN LATE SUN INTO MON.
THU...STRONG LLVL W FLOW IN THE WAKE OF LO PRES SHIFTING NEWD THRU
ONTARIO WL DRAW MUCH COLDER AIR INTO THE UPR LKS. IN FACT...THE
COLDEST GUIDANCE SHOWS H85 TEMPS APRCHG -20C OVER THE WRN CWA BY 00Z
FRI. THE ARRIVAL OF VIGOROUS DEEP LYR QVECTOR DVGC RESULTING FM THIS
INTENSE CAD AND DNVA/MID LVL DRYING WL SUPPRESS ANY LARGE SCALE
PCPN. BUT LES WL DVLP IN THE SN BELTS FAVORED BY THE LLVL W
FLOW...PRIMARILY OVER THE KEWEENAW. SOME MODEL FCST SDNGS SHOW A
PERIOD WHERE THE SHARPER OMEGA WITHIN THE MOIST LYR IS FAVORABLY
ALIGNED WITHIN THE DGZ TO CAUSE A RELATIVELY HI SN/WATER RATIO. SO
ADVYS FOR LES MAY BE NECESSARY FOR THE KEWEENAW. WITH WNW H925 WINDS
UP TO 35-40 KTS AND VIGOROUS CAD THAT WL CAUSE CONSIDERABLE LLVL
DESTABILIZATION...WINDS AT EXPOSED LOCATIONS ESPECIALLY OVER THE
KEWEENAW MAY ALSO APRCH ADVY CRITERIA. ALTHOUGH THESE STRONG WINDS
WL BREAK UP THE DENDRITIC SN FLAKES AND REDUCE THE OTRW FVRBL
SN/WATER RATIOS...THE RESULTING BLSN FM THE SMALLER FLAKES WL
EFFECTIVELY REDUCE VSBY. WITH THE ARCTIC AIR INVASION... TEMPS ARE
LIKELY TO FALL THRU THE DAY.
THU NGT INTO SAT...AS THE LO TO THE NE DRIFTS SLOWLY INTO QUEBEC AND
ARCTIC HI PRES SLIDES FM WRN CANADA INTO THE NRN PLAINS...THE STEADY
FLOW OF VERY COLD AIR IS PROGGED TO SLOWLY VEER MORE TO THE WNW AND
DIMINISH WITH TIME AS H85 TEMPS FALL SLOWLY TO -18C OVER THE E AND
-20C OR -21C OVER THE W BY SAT. THIS TYPICAL WINTER WX REGIME WL
FAVOR NEARLY CONTINUOUS LES IN THE FAVORED SN BELTS. A SHRTWV
TRACKING EWD THRU SRN ONTARIO/NRN LK SUP ON FRI NGT AND ACCOMPANYING
DEEPER MSTR MAY RESULT IN SOME ENHANCEMENT TO THE LES. ALTHOUGH THE
WINDS/BLSN WL BE DIMINISHING GRDLY...EXPECT LES/WINTER WX ADVYS TO
BE IN PLACE FOR THE FAVORED LES BELTS WITH FAVORABLE ALIGNMENT OF
THE LLVL OMEGA WITHIN THE DGZ. WENT HIER THAN MODEL CONSENSUS POPS
FOR LES IN THE FAVORED SN BELTS...USING CLIMATOLOGRY GRIDS TO
EVALUATE THE POPS. AS THE LLVL WINDS DIMINISH...LAND BREEZE CNVGC
MAY PLAY A MORE IMPORTANT ROLE IN ENHANCING THE LES BANDS IN SOME
PLACES...WITH AT LEAST LOCALLY HEAVIER SN FALL APRCHG WARNING
CRITERIA. SN/WATER RATIOS WL ALSO LIKELY BE FVRBL FOR LARGER FLAKES
AS THE FLAKE FRACTURING DIMINISHES. AWAY FM THE FAVORED SN
BELTS...THE WX DURING THIS TIME WL BE VERY COLD BUT DRY. SUB ZERO
MIN TEMPS WITH DAYTIME TEMPS STRUGGLING TO RISE ABV 10F WL THE RULE
OVER THE INTERIOR W HALF WITHIN THE LESS MODIFIED ARCTIC AIR.
SAT NGT/SUN...THE SLOW EWD PUSH OF THE ARCTIC HI CENTER FM THE NRN
PLAINS INTO THE GREAT LKS/SLOWLY BACKING WINDS TO WSW ON SUN WL
CAUSE THE LES TO DIMINISH. DEPENDING ON HOW QUICKLY WAD CLDS SPILL
INTO THE UPR LKS ON SUN TO THE E OF A DEEPENING TROF IN THE
PLAINS...TEMPS AT SOME PLACES OVER THE INTERIOR ON EARLY SUN MRNG
MAY FALL INTO THE TEENS BLO ZERO WITH LGT WINDS UNDER THE ARRIVING
SFC HI CENTER.
EXTENDED...NEXT LARGER SCALE PCPN EPISODE IS LIKELY TO ARRIVE ON SUN
NGT INTO EARLY MON. SOME OF THE LONGER TERM MODELS ARE SHOWING A
PHASING OF THE ARCTIC/POLAR BRANCHES WITH A DEEPER SFC LO TRACKING
THRU THE WCENTRAL GREAT LKS. IF THIS SCENARIO WERE TO VERIFY...A
WDSPRD ADVY SN WL BE PSBL OVER MUCH OF THE CWA. BUT SOME OF THE
GUIDANCE HINTS AT LESS PHASING/A WEAKER SFC LO THAT WOULD CAUSE JUST
A COUPLE OF INCHES. IN THE WAKE OF THIS LO MOVING INTO ONTARIO ON
MON...THE COLDEST AIRMASS OF THE SEASON WITH H85 TEMPS AS LO AS -25
TO -28C WL INVADE THE UPR LKS. NEXT TUE LOOKS PARTICULARLY COLD WITH
A SHARP PRES GRADIENT/NW FLOW THAT MIGHT CAUSE WIND CHILLS TO FALL
TO ADVY LVL. TENDED HIER THAN MODEL CONSENSUS FOR LES POPS IN THE
FAVORED SN BELTS FOR MON THRU TUE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1234 PM EST WED DEC 4 2013
A LOW PRESSURE SYSTEM WILL KEEP PRECIP AT THE TAF SITES INTO
TONIGHT. WARM AIR MOVING INTO THE REGION WILL SWITCH SNOW THIS
MORNING TO RAIN AND FREEZING RAIN AT TIMES INTO EARLY TONIGHT...MOST
LIKELY AT SAW AND MORE LIKELY TO STAY A WINTRY MIX AT IWD AND CMX.
LOTS OF DIFFICULTY FORECASTING EXACT CHANGE OVER TIMES...SO PUT BEST
GUESS INTO TAFS. PRECIP WILL CHANGE BACK TO SNOW TONIGHT AS COLD AIR
COMES IN BEHIND A COLD FRONT...WHILE PRECIP TRANSITIONS FROM AREA
WIDE PRECIP TO LAKE EFFECT SNOW...FAVORING IWD AND ESPECIALLY CMX
INTO THURSDAY. USED CONSENSUS GUIDANCE FOR CIGS/VIS AND MORE
CLIMATOLOGY FOR LAKE EFFECT SNOW LATE IN THE PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 317 PM EST WED DEC 4 2013
LOW PRESSURE OVER WISCONSIN WILL DEEPEN ACROSS CENTRAL AND EASTERN
LAKE SUPERIOR OVERNIGHT...AND EXIT NORTHEAST ACROSS JAMES BAY WHILE
FURTHER DEEPENING THURSDAY NIGHT. THE PERIOD OF STRONG WINDS WILL
CONTINUE THROUGH THURSDAY NIGHT...WITH OUR INITIAL E TO NE WINDS
/GALES TO 35KTS OVER W LAKE SUPERIOR/ BECOMING OUT OF THE S AND SW
FOR ALL BUT FAR W LAKE SUPERIOR OVERNIGHT...BEFORE W GALES OF 35 TO
40 KNOTS START UP THURSDAY MORNING THROUGH THURSDAY NIGHT.
A STRONG ARCTIC HIGH PRESSURE SYSTEM OVER WESTERN CANADA ON THURSDAY
WILL SLIDE ACROSS THE NORTHERN PLAINS ON SATURDAY...AND ACROSS THE
GREAT LAKES SUNDAY. THE HIGH WILL EXIT ACROSS THE NEW ENGLAND STATES
WHILE WEAKENING SLIGHTLY ON MONDAY. EXPECT LOW PRESSURE OVER THE
LOWER MISSISSIPPI VALLEY SUNDAY TO DEEPEN AND SURGE NORTHWARD ACROSS
LAKE HURON LATE SUNDAY NIGHT INTO MONDAY. W TO NW GALES TO 35KTS
WILL BE POSSIBLE AGAIN MONDAY THROUGH TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ THURSDAY
FOR MIZ002-004-005-009>011-084.
LAKE EFFECT SNOW ADVISORY FROM 4 AM TO 7 PM EST THURSDAY FOR
MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 4 AM EST THURSDAY FOR MIZ001-003.
LAKE SUPERIOR...
GALE WARNING FROM 6 AM THURSDAY TO 4 AM EST FRIDAY FOR
LSZ265>267.
GALE WARNING UNTIL 4 AM EST FRIDAY FOR LSZ263-264.
GALE WARNING FROM 8 AM TO 7 PM EST THURSDAY FOR LSZ247-248-250-
251.
GALE WARNING FROM 5 AM EST /4 AM CST/ TO 7 PM EST /6 PM CST/
THURSDAY FOR LSZ241>245.
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THURSDAY FOR LSZ162.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...KC
AVIATION...TITUS
MARINE...KF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
302 PM CST WED DEC 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 257 PM CST WED DEC 4 2013
AN ARCTIC AIRMASS HAS SETTLED ACROSS THE NORTHERN AND CENTRAL
PLAINS...AND H85 TEMPS ARE ON THE ORDER OF 2 TO 3 STANDARD
DEVIATIONS BELOW NORMAL FOR THIS TIME OF YEAR. TEMPERATURES THIS
AFTERNOON HAVE STRUGGLED IN THE ARCTIC AIR AND READINGS AVERAGE IN
THE TEENS/20S ATTM. WINDS CONTINUE TO REMAIN STEADY/GUSTY IN A
TIGHT PRESSURE GRADIENT WITH A DEPARTING SFC LOW ACROSS EASTERN
IOWA AND A 1035MB SURFACE HIGH BUILDING SOUTHEAST FM MONTANA. THE
COMBINATION OF THE GUSTY WINDS AND COLD TEMPS HAVE RESULTED IN
WINDS CHILLS IN THE SINGLE DIGITS THIS AFTERNOON. SNOW FLURRIES
ACROSS OUR EASTERN ZONES CONTINUE WILL CONTINUE TO DIMINISH AS WE
HEAD THRU THE REMAINDER OF THE AFTN IN A SUBSIDENT/CLEARING AREA.
THIS EVENING...A 150KT H25 JET EMERGES FROM THE CENTRAL ROCKIES
AND CROSSES THRU NEBRASKA AND A MID LEVEL TROUGH TRANSLATES ACROSS
THE CENTRAL PLAINS. COLD AIR IS REINFORCED WITH THIS NEXT TROUGH
MOVING THRU THIS EVENING AND A BAND OF MID LEVEL FRONTOGENESIS IS
PROGGED ACROSS OUR SOUTHERN ZONES. IN FAVORABLE JET DYNAMICS AND
PRESENCE OF THE FRONTOGENESIS...A NARROW CORRIDOR OF BANDED
SNOWFALL IS EXPECTED TO DEVELOP DURING THE EVENING. MODELS ARE NOT
IN COMPLETE AGREEMENT ON WHERE THIS BAND WILL SET UP WITH THE GFS
THE FARTHEST NORTH WITH THE BAND...THE 12Z NAM WAS THE FARTHEST
SOUTH WITH THE BAND BUT HAS TRENDED NORTHWARD WITH THE 18Z RUN.
EARLIER RUNS OF THE RAP WERE MORE SIMILAR TO THE CURRENT 18Z
NAM...HOWEVER THE LATEST RUNS OF THE RAP HAVE TRENDED FARTHER
SOUTH INTO CENTRAL KANSAS WITH THE POSITION. THIS BEING
SAID...NORTH CENTRAL KANSAS IS STILL THE MOST FAVORABLE LOCATION
FOR SNOWFALL THIS EVENING. POPS HAVE BEEN INCREASED AND WHERE BAND
SETS UP...SOME HALF INCH SNOWFALL AMOUNTS OR SO ARE NOT OUT OF THE
QUESTION. FARTHER NORTH OF THE BAND...FLURRIES ARE POSSIBLE UNTIL
THE MID LEVEL TROUGH AXIS PASSES TO THE EAST BY AROUND MIDNIGHT OR
SHORTLY THEREAFTER.
OVERNIGHT TEMPERATURES WILL REMAIN FRIGID AND CLOUDS BEGIN TO SCOUR
BEFORE DAYBREAK. HAVE WENT WITH LOW TEMPS IN THE SINGLE DIGITS
ABOVE ZERO TONIGHT AND WHEN COMBINED WITH THE STEADY NORTHWESTERLY
WINDS...WIND CHILL READINGS WILL DROP TO ROUGHLY 8 TO 18 DEGREES
BELOW ZERO ACROSS OUR CWA. THE COLDEST READINGS WILL BE ACROSS OUR
NW ZONES...AND THE 18 BELOW VALUES REMAIN SHY OF WIND CHILL ADVISORY
CRITERIA SO WILL HOLD OFF ON HEADLINE AND CONTINUE TO MENTION COLD
WIND CHILLS IN THE HWO.
THE ARCTIC AIRMASS WILL REMAIN IN PLACE ON THURSDAY...WITH FRIGID
-18C AIR SETTLING IN AT H85. THE SFC RIDGE AXIS WILL CONTINUE TO
NOSE SOUTHEAST ONTO THE PLAINS AND DRY AND VERY COLD WEATHER IS
FORECAST. TEMPS WILL CONTINUE TO STRUGGLE IN THE COLD AIRMASS AND
WILL GIVE TEMPS ABOUT A 10 DEGREE RISE FROM MORNING LOWS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 257 PM CST WED DEC 4 2013
THURSDAY NIGHT THROUGH WEDNESDAY. MAIN FORECAST
CONCERNS WILL BE CHANCE FOR SNOW SATURDAY NIGHT THROUGH SUNDAY NIGHT
AND COLD TEMPERATURES THROUGH THE PERIOD.
A COLD SURFACE HIGH PRESSURE SYSTEM WILL PUSH INTO THE AREA FOR
THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE CENTER OF THE HIGH WILL
REMAIN NORTH AND EAST OF THE AREA AND WINDS WILL CONTINUE TO BE
AROUND 5 TO 15 MPH. WITH THE TEMPERATURES ALREADY IN THE SINGLE
DIGITS ABOVE AND BELOW ZERO...THE WIND CHILL VALUES WILL DROP INTO
THE -10 TO -20 DEGREE RANGE ACROSS THE AREA.
ON SATURDAY THE SURFACE HIGH MOVES OFF TO THE EAST AND WINDS TURN TO
THE SOUTH. AN UPPER LEVEL WAVE APPROACHES THE AREA FROM THE
SOUTHWEST. THERE IS INCREASING MOISTURE ACROSS THE AREA AND CLOUDS
WILL INCREASE.
SATURDAY NIGHT THROUGH SUNDAY NIGHT THE UPPER LEVEL WAVE WILL MOVE
THROUGH THE REGION. STARTING SATURDAY NIGHT THERE IS WARM ADVECTION
OF MOIST AIR OVER THE COLD SURFACE. EXPECT SNOW TO START ACROSS THE
AREA DURING THE EVENING AND CONTINUE INTO SUNDAY. THE BEST CHANCES
WILL LIKELY BE LATE SATURDAY NIGHT INTO SUNDAY MORNING. MODELS HAVE
SOME VARIABLE QPF AMOUNTS BUT IT LOOKS LIKE THERE WILL BE
ACCUMULATING SNOWFALL. WITH THE COLD TEMPERATURES THERE WILL MOST
LIKELY BE LIGHT FLUFFY SNOWFALL. AN ADVANTAGE IS THAT CURRENTLY
THERE IS NOT SIGNIFICANT WIND WITH THE SYSTEM. BY SUNDAY EVENING THE
MAIN UPPER WAVE IS THROUGH THE AREA AND THE SNOWFALL WILL GRADUALLY
COME TO AN END SUNDAY NIGHT.
A COLD SURFACE HIGH PRESSURE SYSTEM MOVES INTO THE SOUTHERN PLAINS
ON MONDAY AND COLD TEMPERATURES WILL CONTINUE ACROSS THE AREA MONDAY
INTO TUESDAY. TUESDAY NIGHT ANOTHER WEAK UPPER LEVEL WAVE APPROACHES
THE AREA. THE MAIN WAVE IS FURTHER TO THE NORTH. MOST OF THE
MOISTURE IS FURTHER NORTH AND NOT MUCH CHANGE FROM MONDAY AND
TUESDAY. THE ONLY CHANGE WILL BE A POTENTIAL FOR SOME SLIGHTLY
WARMER TEMPERATURES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1120 AM CST WED DEC 4 2013
KGRI WILL REMAIN UNDER THE INFLUENCE OF AN ARCTIC AIRMASS THROUGH
THE TAF PERIOD. HAVE MAINTAINED MVFR CIGS INTO THE OVERNIGHT
PERIOD...THEN SCATTERED CLOUDS BY THURSDAY MORNING BEHIND PASSAGE
OF MID LEVEL TROUGH AXIS. WINDS WILL REMAIN STEADY/GUSTY FM THE
NORTHWEST...WITH WIND SPEEDS DIMINISHING TO SOME DEGREE THURSDAY
MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...FAY
LONG TERM...JCB
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1154 AM CST WED DEC 4 2013
.AVIATION...18Z TAFS FOR KOMA...KLNK AND KOFK.
CURRENT OBS INDICATE AREAS OF -SN ALONG AND WEST OF AN AXIS FROM
ABOUT KFSD TO KHDE. -SN ACTIVITY WAS TRACKING NE IN ASSOCIATION
WITH AN UPPER DISTURBANCE MOVING TWD THE DAKOTAS. KOFK WAS
REPORTING -SN...BUT RADAR TRENDS SUGGEST ACTIVITY IS N0T MAKING
MUCH OF A PUSH EAST. SUSPECT -SN WILL CONTINUE THE NEXT COUPLE
HOURS AT KOFK THUS WILL MAINTAIN TEMPO GROUP TILL 21Z.
OTHERWISE...MVFR CIGS EXTENDED FROM ERN NEB TO OVER MOST OF KS.
HOWEVER EXPECT VFR CIGS FL050 AGL CURRENTLY OVER CNTRL NEB WILL
GRADUALLY MOVE EAST...ALLOWING FOR IMPROVING CONDITIONS AT ALL
TERMINALS LATE THIS AFTN/EARLY EVENING TIME FRAME. SEEMS LIKELY AT
THIS POINT THAT VFR CIGS WILL PERSIST THEN THRU THE REST OF THE
FCST PD AT ALL SITES.
DEE
&&
PREV DISCUSSION... /ISSUED 305 AM CST WED DEC 4 2013/
DISCUSSION...
LOW PRESSURE WAS LOCATED OVER NORTH CENTRAL OKLAHOMA AT 08Z
WITH A STATIONARY FRONT STRETCHING ACROSS EASTERN KANSAS INTO
CENTRAL IOWA. RADAR SHOWS PRIMARY BAND OF SNOW EXTENDS FROM NORTH
CENTRAL NEBRASKA INTO SOUTHEAST SOUTH DAKOTA AND SOUTHWEST
MINNESOTA...WHILE WIDESPREAD FOG AND DRIZZLE WAS LOCATED ALONG
THE STATIONARY FRONT. SOME LIGHT SNOW STILL LIKELY FOR NORTHEAST
BORDER AREA THIS MORNING AS SYSTEM LIFTS NORTHEAST WITH UP TO
AN INCH POSSIBLE BEFORE ENDING THIS AFTERNOON.
FREEZING DRIZZLE HAS STARTED TO BECOME MORE WIDESPREAD IN EASTERN
NEBRASKA AS THE COLDER AIR PUSHES INTO THE AREA. RAP FORECAST
SOUNDINGS SUGGEST THE POTENTIAL FOR FREEZING DRIZZLE THROUGH MOST
OF THE MORNING FOR SOUTHEAST NEBRASKA AND SOUTHWEST IOWA BEFORE
SOMEWHAT DRIER AIR WORKS INTO THE LOW LEVELS. WILL PROBABLY WAIT
UNTIL JUST BEFORE ISSUANCE TO BETTER ASSES EXTENT OF THE PRECIP
BUT ADVISORY SEEMS LIKELY AT SOME POINT.
STRONG COLD ADVECTION FINALLY ARRIVES DURING THE AFTERNOON AS AREA
COMES ON THE BACK SIDE OF THE DEPARTING SYSTEM. FOR THE REMAINDER
OF THE SHORT TERM TEMPERATURES BECOME THE PRIMARY FORECAST CONCERN
WITH VERY COLD WIND CHILLS DEVELOPING ESPECIALLY IN THE NORTH HALF
OF THE AREA.
LITTLE CHANGE IN THE EXTENDED PERIOD WITH STILL SOME CHANCE OF
SNOW LATE SATURDAY INTO SUNDAY WITH COLD TEMPERATURES CONTINUING.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
526 AM CST WED DEC 4 2013
.AVIATION...12Z TAFS FOR KOMA...KLNK AND KOFK. FREEZING DRIZZLE
WILL BE THE PRIMARY CONCERN AT KLNK/KOMA THROUGH ABOUT
15-16Z...WITH IFR CONDITIONS EXPECTED. FURTHER NORTH AT
KOFK...MVFR CLOUDS WILL PERSIST...AND STILL COULD SEE A FEW SNOW
SHOWERS OR FLURRIES AT THAT LOCATION. OTHERWISE...MVFR CLOUDS
COULD PERSIST THROUGH THE PERIOD...WITH NORTHWEST WINDS AT 20 TO
30 MPH.
DEWALD
&&
.PREV DISCUSSION... /ISSUED 305 AM CST WED DEC 4 2013/
DISCUSSION...
LOW PRESSURE WAS LOCATED OVER NORTH CENTRAL OKLAHOMA AT 08Z
WITH A STATIONARY FRONT STRETCHING ACROSS EASTERN KANSAS INTO
CENTRAL IOWA. RADAR SHOWS PRIMARY BAND OF SNOW EXTENDS FROM NORTH
CENTRAL NEBRASKA INTO SOUTHEAST SOUTH DAKOTA AND SOUTHWEST
MINNESOTA...WHILE WIDESPREAD FOG AND DRIZZLE WAS LOCATED ALONG
THE STATIONARY FRONT. SOME LIGHT SNOW STILL LIKELY FOR NORTHEAST
BORDER AREA THIS MORNING AS SYSTEM LIFTS NORTHEAST WITH UP TO
AN INCH POSSIBLE BEFORE ENDING THIS AFTERNOON.
FREEZING DRIZZLE HAS STARTED TO BECOME MORE WIDESPREAD IN EASTERN
NEBRASKA AS THE COLDER AIR PUSHES INTO THE AREA. RAP FORECAST
SOUNDINGS SUGGEST THE POTENTIAL FOR FREEZING DRIZZLE THROUGH MOST
OF THE MORNING FOR SOUTHEAST NEBRASKA AND SOUTHWEST IOWA BEFORE
SOMEWHAT DRIER AIR WORKS INTO THE LOW LEVELS. WILL PROBABLY WAIT
UNTIL JUST BEFORE ISSUANCE TO BETTER ASSES EXTENT OF THE PRECIP
BUT ADVISORY SEEMS LIKELY AT SOME POINT.
STRONG COLD ADVECTION FINALLY ARRIVES DURING THE AFTERNOON AS AREA
COMES ON THE BACK SIDE OF THE DEPARTING SYSTEM. FOR THE REMAINDER
OF THE SHORT TERM TEMPERATURES BECOME THE PRIMARY FORECAST CONCERN
WITH VERY COLD WIND CHILLS DEVELOPING ESPECIALLY IN THE NORTH HALF
OF THE AREA.
LITTLE CHANGE IN THE EXTENDED PERIOD WITH STILL SOME CHANCE OF
SNOW LATE SATURDAY INTO SUNDAY WITH COLD TEMPERATURES CONTINUING.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR NEZ034-
044-045-050>053-065>068-078-088>090-092.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR NEZ091-093.
IA...WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR IAZ043-
055-056-069-079.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR IAZ080-090-091.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
305 AM CST WED DEC 4 2013
.DISCUSSION...
LOW PRESSURE WAS LOCATED OVER NORTH CENTRAL OKLAHOMA AT 08Z
WITH A STATIONARY FRONT STRETCHING ACROSS EASTERN KANSAS INTO
CENTRAL IOWA. RADAR SHOWS PRIMARY BAND OF SNOW EXTENDS FROM NORTH
CENTRAL NEBRASKA INTO SOUTHEAST SOUTH DAKOTA AND SOUTHWEST
MINNESOTA...WHILE WIDESPREAD FOG AND DRIZZLE WAS LOCATED ALONG
THE STATIONARY FRONT. SOME LIGHT SNOW STILL LIKELY FOR NORTHEAST
BORDER AREA THIS MORNING AS SYSTEM LIFTS NORTHEAST WITH UP TO
AN INCH POSSIBLE BEFORE ENDING THIS AFTERNOON.
FREEZING DRIZZLE HAS STARTED TO BECOME MORE WIDESPREAD IN EASTERN
NEBRASKA AS THE COLDER AIR PUSHES INTO THE AREA. RAP FORECAST
SOUNDINGS SUGGEST THE POTENTIAL FOR FREEZING DRIZZLE THROUGH MOST
OF THE MORNING FOR SOUTHEAST NEBRASKA AND SOUTHWEST IOWA BEFORE
SOMEWHAT DRIER AIR WORKS INTO THE LOW LEVELS. WILL PROBABLY WAIT
UNTIL JUST BEFORE ISSUANCE TO BETTER ASSES EXTENT OF THE PRECIP
BUT ADVISORY SEEMS LIKELY AT SOME POINT.
STRONG COLD ADVECTION FINALLY ARRIVES DURING THE AFTERNOON AS AREA
COMES ON THE BACK SIDE OF THE DEPARTING SYSTEM. FOR THE REMAINDER
OF THE SHORT TERM TEMPERATURES BECOME THE PRIMARY FORECAST CONCERN
WITH VERY COLD WIND CHILLS DEVELOPING ESPECIALLY IN THE NORTH HALF
OF THE AREA.
LITTLE CHANGE IN THE EXTENDED PERIOD WITH STILL SOME CHANCE OF
SNOW LATE SATURDAY INTO SUNDAY WITH COLD TEMPERATURES CONTINUING.
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
COLDER AIR WILL CONTINUE TO GRADUALLY WORK SE ACROSS TAF SITES
THROUGH WEDNESDAY. ALTHOUGH CIGS INTO MIDDAY WEDNESDAY WILL GENERALLY
BE IFR...THEY COULD OCCASIONALLY BE A BIT HIGHER. VSBYS COULD
BRIEFLY DROP BELOW 3SM AT KOMA ABSENT ANY PRECIP AS THAT LOCATION
REMAINS ON BATTLEGROUND BETWEEN SLIGHTLY DRIER MODIFIED ARCTIC
AIR OVER CNTRL NEBR AND MOISTER AIR WORKING SSW OVER IA. LATER
TONIGHT LIGHT PRECIP COULD DEVELOP AT ALL SITES WITH FREEZING
DRIZZLE POSSIBLE. EVEN A PERIOD OF SLEET IS POSSIBLE AT KOMA/KLNK
WED AM AS COLDER AIR BECOMES DEEPER...BUT PERIOD APPEARED BRIEF
AND AMOUNT/OCCURRENCE NOT QUITE HIGH ENOUGH TO INCLUDE IN TAF.
CHANCES OF A PERIOD OF LIGHT SNOW STILL APPEARED HIGH ENOUGH AT
KOFK TO INCLUDE A PERIOD OF LIGHT SNOW LATE TONIGHT.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR NEZ034-
044-045-050>053-065>068-078-088>090-092.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR NEZ091-093.
IA...WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR IAZ043-
055-056-069-079.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR IAZ080-090-091.
&&
$$
FOBERT/CHERMOK
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1117 PM CST TUE DEC 3 2013
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
COLDER AIR WILL CONTINUE TO GRADUALLY WORK SE ACROSS TAF SITES
THROUGH WEDNESDAY. ALTHOUGH CIGS INTO MIDDAY WEDNESDAY WILL GENERALLY
BE IFR...THEY COULD OCCASIONALLY BE A BIT HIGHER. VSBYS COULD
BRIEFLY DROP BELOW 3SM AT KOMA ABSENT ANY PRECIP AS THAT LOCATION
REMAINS ON BATTLEGROUND BETWEEN SLIGHTLY DRIER MODIFIED ARCTIC
AIR OVER CNTRL NEBR AND MOISTER AIR WORKING SSW OVER IA. LATER
TONIGHT LIGHT PRECIP COULD DEVELOP AT ALL SITES WITH FREEZING
DRIZZLE POSSIBLE. EVEN A PERIOD OF SLEET IS POSSIBLE AT KOMA/KLNK
WED AM AS COLDER AIR BECOMES DEEPER...BUT PERIOD APPEARED BRIEF
AND AMOUNT/OCCURRENCE NOT QUITE HIGH ENOUGH TO INCLUDE IN TAF.
CHANCES OF A PERIOD OF LIGHT SNOW STILL APPEARED HIGH ENOUGH AT
KOFK TO INCLUDE A PERIOD OF LIGHT SNOW LATE TONIGHT.
CHERMOK
&&
.PREV DISCUSSION... /ISSUED 916 PM CST TUE DEC 3 2013/
UPDATE...
MADE SOME MINOR TEMPERATURE ADJUSTMENTS UPWARD SOUTHEAST 1/2 OR SO
TNGT AND ALSO REDUCED PRECIP CHANCES NORTHEAST THIS EVENING.
DISCUSSION...
COLD AIR IS HAVING MORE SUCCESS DROPPING SOUTH THAN SOUTHEAST AND
COLDEST TONIGHT WILL PROBABLY STAY TO OUR N THROUGH WEST. THUS
BUMPED UP MIN TEMPS A FEW DEGREES FAR E AND SE. ALSO FIRST BATCH
OF RADAR RETURNS HAVE ENDED OVER NERN NEBR AND SHORT TERM MODELS
SUGGEST MEASURABLE MAY NOT RETURN UNTIL LATE TONIGHT/EARLY
WEDNESDAY. THUS REDUCED POPS NERN ZONES THIS EVENING BUT
INCREASED LATER TONIGHT. LATEST RAP SOUNDINGS STILL SUGGEST SOME
FREEZING DRIZZLE POSSIBLE LATE TONIGHT/EARLY WEDNESDAY TOWARD LNK
AND OMAHA...AND AS COLD AIR DEEPENS...IF PRECIP CONTINUES...SOME
SLEET/SNOW PELLETS POSSIBLE AS WELL. JUST LEFT PATCHY FREEZING
DRIZZLE MENTION FOR NOW AS MEASURABLE DID NOT APPEAR TOO LIKELY
YET.
CHERMOK
PREV DISCUSSION... /ISSUED 335 PM CST TUE DEC 3 2013/
DISCUSSION...
LATEST OBJECTIVE SURFACE ANALYSIS DEPICTS LOW PRESSURE OVER THE
OKLAHOMA PANHANDLE....SPECIFICALLY JUST EAST OF COLORADO SPRINGS
AS OF 21Z. LATEST MODEL GUIDANCE TRANSLATES THIS FEATURE ALONG
THE KANSAS/OKLAHOMA BORDER OVERNIGHT AND THEN TO EASTERN IOWA BY
WEDNESDAY AFTERNOON. THIS RESULTS IN COLD AIR DROPPING ACROSS
THE CENTRAL PLAINS FOR THE NEXT SEVERAL DAYS. AS THIS COLD AIR
DIPS SOUTH...MID LEVEL FORCING CO-LOCATED WITH AVAILABLE MOISTURE
WILL GENERATE ACCUMULATING SNOW OVER PORTIONS OF
KNOX/CEDAR/ANTELOPE/PIERCE COUNTIES OVERNIGHT. BASED ON THE LATEST
INFORMATION...THE BETTER FORCING AND HIGHER ACCUMULATIONS ARE
LIKELY TO VERIFY ACROSS SOUTHEAST SOUTH DAKOTA. GIVEN THE EXPECTED
MOISTURE TRACK DECIDED TO UP SNOW AMOUNTS A BIT FOR NORTHEAST
NEBRASKA...WITH 1-3 INCHES OF SNOW EXPECTED ACROSS KNOX
COUNTY...AND A HALF INCH TO 1 INCH ELSEWHERE ACROSS NORTHEAST
NEBRASKA. AS THE BOUNDARY LAYER TRANSITIONS BELOW FREEZING SOME
ICE PELLETS/SLEET ARE ALSO POSSIBLE AS HAS BEEN ALREADY REPORTED
AT WAYNE. OPTED TO REMOVE ANY MENTION OF FREEZING RAIN AS
PROFILES SUGGEST ITS UNLIKELY TO OCCUR. FURTHER SOUTH LOW LEVEL
MOISTURE PROFILES ARE MEAGER AND SOUTHEAST OF THE PREVIOUSLY
MENTIONED COUNTIES IT APPEARS FREEZING DRIZZLE IS MORE LIKELY
GIVEN THE LACK OF APPRECIABLE FORCING AND ICE IN THE CLOUD. THIS
FREEZING DRIZZLE COULD LINGER THROUGH RUSH HOUR AND POSSIBLY LATER
IN THE MORNING. BY AFTERNOON THE LOW LEVELS SHOULD DRY OUT ENOUGH
TO END ANY DRIZZLE CONCERNS.
BEYOND WEDNESDAY NIGHT QUIET WEATHER LOOKS TO BE THE RULE THOUGH
VERY COLD AIR WILL REMAIN IN PLACE. DAYTIME HIGHS WILL STRUGGLE TO
GET OUT THE TEENS AND OVERNIGHT LOWS WILL FLIRT WITH ZERO EACH
NIGHT. BY FRIDAY GUIDANCE IS HINTING AT A WINTER STORM OVER
KANSAS AND MISSOURI...FOR NOW THIS LOOKS TO STAY SOUTH OF
NEBRASKA AND IOWA.
PEARSON
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
A BROAD UPPER TROUGH WILL KEEP THE REGION COLD THROUGHOUT THE
EXTENDED PERIOD. SOUTHWESTERLY FLOW ALOFT WILL SEND A SERIES OF
LITTLE IMPULSES TO THE AREA AND WILL PROVIDE A SMALL CHANCE FOR
LIGHT SNOW SATURDAY NIGHT INTO SUNDAY MORNING. MOISTURE IS
LIMITED...SO NOT EXPECTING MORE THAN AN INCH OR SO DURING THIS TIME.
BETTER FORCING COMES INTO PLAY SUNDAY INTO SUNDAY NIGHT AS FORCING
FROM A STRONG SHORTWAVE TROUGH MOVES NORTHEAST OUT OF COLORADO. IN
ADDITION...THE LEFT FRONT QUAD OF A 150KT 300 MB JET WILL BE PASSING
OVERHEAD PROVIDING STRONG UPPER DIVERGENCE. WE CURRENTLY HAVE CHANCE
POPS GOING AND THAT MAY NEED TO BE BUMPED UP WITH LATER FORECAST IF
THE FORCING IS STILL LOOKING STRONG. A VERY STRONG COLD PUSH WILL
SINK INTO THE REGION MONDAY NIGHT INTO TUESDAY MORNING WITH PROGGED
850MB TEMPS ANYWHERE FROM -20C TO -25C.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
136 PM EST WED DEC 4 2013
.SYNOPSIS...
A WEAK WARM FRONT WILL LIFT NORTH THROUGH THE REGION TODAY.
OFFSHORE HIGH PRESSURE THEN INFLUENCES THE AREA WEATHER THROUGH
THE END OF THE WEEK. A COLD FRONT WILL APPROACH LATE IN THE WEEK
AND WILL CROSS THE REGION ON SATURDAY. A STRONGER COLD FRONT WILL
CROSS THE REGION TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1030 AM WED...EXTENDED HIGHER POPS INTO EARLY AFTN WITH PATCHY
RAIN EXPECTED TO AFFECT AREA SEVERAL MORE HOURS. ALSO KEPT CLOUDS IN
LONGER THIS AFTN AND LOWERED MAX TEMPS SEVERAL DEGS.
/PREVIOUS DISCUSSION/
AS OF 600 AM WEDNESDAY...A WEAK DISTURBANCE IN THE LOW AMPLITUDE
FLOW ALOFT WILL IMPINGE ON MOIST LOW LEVEL AIRMASS WHERE WARM
ADVECTION WAS PRODUCING SUFFICIENT ISENTROPIC UPGLIDE TO PRODUCE
WIDESPREAD MOSTLY LIGHT PRECIPITATION THIS MORNING. AT THE SURFACE
THE PRECIPITATION WAS ASSOCIATED WITH A WEAK NORTHWARD MOVING WARM
FRONT WHICH IS FORECAST TO MOVE THROUGH THE AREA LATER TODAY.
REGIONAL RADARS INDICATE AN EXTENSIVE AREA OF RAIN THAT EXTENDS
ACROSS THE CAROLINAS TO SOUTHEAST VIRGINIA. WITH PW VALUES FORECAST
TO RISE TO AROUND 1.3", SOME OF THE PRECIPITATION COULD PRODUCE
BRIEF LOCAL DOWNPOURS AT TIMES. EXPECTING STORM TOTAL QPF OF 0.25 TO
0.50" IN MOST LOCATIONS WITH SOME LOCALLY HEAVIER AMOUNTS. SIDED
WITH THE SLIGHTLY FASTER ECMWF/GFS SOLUTIONS WHICH INDICATE THAT THE
RAIN WILL BE TAPERING OFF FROM WEST TO EAST BEGINNING EARLY THIS
AFTERNOON. CLOUDS WILL BE SLOWER TO DISSIPATE AND EXPECT SKIES TO
REMAIN CLOUDY/MOSTLY CLOUDY THROUGHOUT THE DAY. DESPITE THE
CLOUDS/PRECIPITATION, TEMPERATURES ARE FORECAST TO BE ABOVE NORMAL
DUE TO SOUTHERLY FLOW WITH READINGS IN THE MIDDLE TO UPPER 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
AS OF 310 AM WEDNESDAY...COULD BE A LINGERING SHOWER OR TWO ALONG
THE OUTER BANKS EARLY, OTHERWISE EXPECT CLOUDS TO DIMINISH DURING
THE EVENING. THE LOW LEVELS WILL REMAIN RATHER MOIST THOUGH, AND
THIS WOULD TEND TO SUPPORT THE DEVELOPMENT OF LOW STRATUS CLOUDS.
IN ADDITION IF WINDS CAN DECOUPLE, WHICH IS UNCERTAIN AT THIS
TIME, THEN PATCHY DENSE FOG COULD ALSO DEVELOP. EXPECT MILD LOWS
IN THE LOWER TO MIDDLE 50S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 310 AM WED...A LONGWAVE NRN STREAM UPPER TROUGH WILL BE IN
PLACE ACROSS THE WRN CONUS THROUGH THE LATTER HALF OF THE WEEK
WHILE SW/NE ORIENTED UPPER RIDGE AMPLIFIES ACROSS THE SRN GOM AND
OFF THE SOUTHEAST COAST BRINGING SW FLOW ALOFT ACROSS THE ERN
CONUS. ABUNDANT PACIFIC MOISTURE WILL BE TRANSPORTED ACROSS THE
SOUTHERN PLAINS IN THE MID-ATLANTIC WHILE A SLOW MOVING COLD FRONT
PUSHES ACROSS THE MID-WEST AND MID-ATLANTIC STATES. DEEPEST
MOISTURE AND BEST UPPER LEVEL DYNAMICS WILL REMAIN NORTH AND WEST
OF THE REGION AND EXPECT MAINLY DRY CONDITIONS BUT WILL SEE
INCREASED CLOUD COVER ACROSS ERN NC. A WARMING TREND CONTINUES
WITH SFC HIGH OFFSHORE BRINGING INCREASING SWLY FLOW THROUGH THE
END OF THE WEEK. MODELS TRENDING A LITTLE WARMER WITH TEMPS THU
AND FRI AND EXPECT HIGH IN THE MID 70S THU AND POSSIBLY A FEW
UPPER 70S ON FRI...ABOUT 10-15 DEGREES ABOVE NORMAL.
UPPER LEVEL ENERGY EJECTING NEWD OUT OF THE UPPER TROUGH WILL AID IN
PUSHING THE COLD FRONT THROUGH THE REGION EARLY SATURDAY. BEST
PRECIP CHANCES OCCUR AFTER FROPA WITH SWLY UPPER LEVEL FLOW AND
MOISTURE OVERRUNNING THE SHALLOW COLD AIR WITH HIGH PRES BUILDING IN
FROM THE N WHICH CONTINUES INTO SUNDAY. MODELS STILL CONVERGING ON
THE TIMING OF THE FRONT WHICH WILL HAVE A BIG IMPACT TEMPS FRI NIGHT
AND SAT. PREFERRED MODEL IS THE ECMWF WHICH PUSHES THE FRONT THROUGH
AFTER 12Z SAT WHICH WILL KEEP THE REGION IN THE WARM SECTOR FRIDAY
NIGHT...WITH FALLING TEMPS AFTER FROPA SATURDAY.
THE FRONT WILL LIFT BACK NORTH AS A WARM FRONT SUN NIGHT AS THE
LONGWAVE WEST COAST TROUGH FINALLY PUSHES EASTWARD...LIFTING A
DEEPENING AREA OF LOW PRES AREA INTO THE GREAT LAKES. THE REGION
WILL BE BACK IN THE WARM SECTOR MONDAY WITH TEMPS WARMING BACK ABOVE
NORMAL WITH POPS LOWERING AS ISENTROPIC LIFT LIFT SHIFTS NORTH.
MODELS ALSO CONTINUE TO SHOW MINIMAL INSTABILITY DEVELOPING ACROSS
THE REGION MONDAY WITH SWLY FLOW...THOUGH WILL NOT INCLUDE MENTION
OF THUNDER AT THIS TIME. THE TRAILING COLD FRONT IS CURRENTLY
PROGGED TO PUSH THROUGH THE REGION TUESDAY BRINGING A GOOD CHANCE
OF RAIN ONCE AGAIN. AN ARCTIC AIRMASS BUILDS IN BEHIND THIS FRONT
AND EXPECT BELOW NORMAL TEMPS FOR THE MIDDLE OF NEXT WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
SHORT TERM /THROUGH 18Z WEDNESDAY/...
AS OF 100 PM WEDNESDAY...MOST OF THE STEADY RAIN HAS MOVED EAST OF ALL
TAF SITES. SATELLITE IMAGES CONTINUE TO SHOW AN IMPROVING TRENDS
OF CLOUDS HEIGHTS BECOMING TO MVFR. THERE IS MODERATE CONFIDENCE OF
CEILING HEIGHTS REACHING TO VFR. IF CONDITIONS BECOME VFR...IT CAN
OCCUR LATE AFTERNOON INTO THE EVENING AND SHOULD BE BRIEF AS
THERE IS A LARGE AMOUNT OF LOW LEVEL MOISTURE.
WITH SATURATED LOW LEVELS AND WINDS EXPECTED TO DECOUPLE TONIGHT..THIS
CAN LEAD TO LOW LEVEL STRATUS AND FOG DEVELOPMENT LATE NIGHT INTO
THURSDAY MORNING. GUIDANCE MODELS HAVE A GOOD AGREEMENT WITH
CONDITIONS BECOMING IFR/LIFR. AT THIS TIME...KEPT CONDITIONS TO
IFR FOR ALL TAF SITES. CONDITIONS ARE EXPECTED TO IMPROVE SLOWLY
TOMORROW LATE MORNING TO MVFR.
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 310 AM WED...PRED VFR CONDITIONS EXPECTED THU THROUGH
FRI...THOUGH PATCHY FOG/STRATUS WILL BE POSSIBLE EACH MORNING WITH
MOIST BL. A COLD FRONT WILL APPROACH THE AREA FROM THE NW FRI
NIGHT...MOVING THROUGH THE TERMINALS SAT MORNING. PROLONGED PERIOD
OF SUB-VFR CONDITIONS EXPECTED TO DEVELOP AFTER FRONTAL PASSAGE
SAT AND CONTINUE THROUGH MUCH OF SUNDAY WITH WIDESPREAD RAIN
EXPECTED. N/NE WIND GUSTS 15-20KT WILL DEVELOP BEHIND THE FRONT
SATURDAY AFTERNOON AS WELL. THE FRONT WILL LIFT BACK THROUGH THE
AREA SUN NIGHT WITH PRECIP CHANCES DIMINISHING AND LOWER CIGS
LIFTING N OF THE REGION BUT AREA OF FOGS WILL BE POSSIBLE.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 1030 AM WED...ADJUSTED WINDS BASED ON LATEST OBS AND MESO
MODEL FCSTS. WARM FRONT STILL OVER SRN SECTIONS WITH SRLY WINDS 15
KTS OBSERVED AT 30 SE NEW RIVER INLET BUOY BUT LIGHT SE WINDS REST
OF AREA. UPDATED WITH BLEND OF RUC13 AND NAM12 FOR SLIGHTLY SLOWER
PROGRESSION OF WINDS BECOME SRLY THIS AFTN. NO CHANGES WITH SEAS.
/PREVIOUS DISCUSSION/
AS OF 600 AM WEDNESDAY...SOUTHERLY FLOW 15 KT OR LESS IS EXPECTED
ACROSS THE WATERS THROUGH TONIGHT AS A WEAK WARM FRONT MOVES
THROUGH THE REGION. SEAS WILL REMAIN 2 TO 4 FT THROUGH THE PERIOD.
LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 310 AM WED...SW FLOW GENERALLY 15KT OR LESS EXPECTED THU
WITH SEAS 2-4FT. SCA CONDITIONS EXPECTED TO DEVELOP EARLY FRI
MORNING AND CONTINUE THROUGH THE WEEKEND. PRESSURE GRADIENTS WILL
TIGHTEN LATE IN THE WEEK AS A FRONT APPROACHES FROM THE NW
ALLOWING SW WINDS TO INCREASE TO 15-25KT AND SEAS BUILD TO
4-7FT...HIGHEST SOUTH OF OREGON INLET. THERE WILL BE THE POTENTIAL
FOR SEA FOG TO DEVELOP ACROSS THE WATERS THU AND FRI GIVEN
EXPECTED AIR/WATER TEMPS AND MOIST SW FLOW. THE COLD FRONT WILL
MOVE THROUGH THE WATERS SAT...AND EXPECT GOOD NORTHERLY SURGE
15-25KT BEHIND THE FRONT...WORKING ITS WAY FROM NORTH TO SOUTH
THROUGH THE DAY...WITH SEAS AROUND 4-7FT. A WAVE WILL DEVELOP
ALONG THE FRONT TO THE SOUTH SUNDAY...THEN SLOWLY LIFT BACK NORTH
ACROSS THE WATERS LATE SUN AND SUN NIGHT WITH VEERING WINDS.
&&
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JME
NEAR TERM...JME
SHORT TERM...JME
LONG TERM...SK/CQD
AVIATION...CQD/BM
MARINE...JME/CQD
CLIMATE...
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1241 PM CST WED DEC 4 2013
.UPDATE...
ISSUED AT 1241 PM CST WED DEC 4 2013
SEE LSR REPORTS FOR LATEST SNOWFALL TOTALS. THESE OBSERVATIONS ARE
MATCHING THE PREVIOUS UPDATE AND THE FORECAST APPEARS ON TRACK.
WIND SPEEDS ARE ALSO BEHAVING...AND GUIDANCE INDICATES SPEEDS
SHOULD NOT GET TOO MUCH HIGHER. SO...THE PREVIOUS UPDATE INDICATED
STORM TOTAL SNOWFALL OF 4 TO 8 ACROSS SOUTHEAST NORTH DAKOTA INTO
THE SOUTHERN VALLEY...WITH 6 TO 12 INCHES ACROSS THE REMAINDER OF
EASTERN NORTH DAKOTA INTO NORTHWESTERN MINNESOTA. REMEMBER...THESE
ARE TOTALS THAT INCLUDE TUESDAY INTO THURSDAY MORNING. ADDITIONAL
SNOWFALL (AFTER 18Z) SHOULD RANGE FROM 1 TO 3 INCHES WESTERN FA INTO
THE SOUTHERN VALLEY...3 TO 6 INCHES NORTHERN VALLEY TO PARK RAPIDS
AREA...AND 6 TO 9 INCHES NORTHWESTERN MN.
UPDATE ISSUED AT 1032 AM CST WED DEC 4 2013
12Z NAM HAS COME IN WITH HIGHER QPF TOTALS FROM 12Z WED TO 12Z
THUR...AND THE 15Z RAP MOSTLY AGREES. THESE MODELS APPEAR TO BE
PICKING UP ON MESO-SCALE FORCING THAT THE GFS/ECMWF/SREF/GEM ARE
NOT INCLUDING. CURRENT RADAR IMAGERY WOULD APPEAR TO INDICATE AND
AREA OF STRONGER FORCING FROM SE NORTH DAKOTA INTO NORTHWEST
MINNESOTA...WHICH THE NAM/RAP SHOW IN THEIR QPF FIELDS. SNOW
RATIOS ARE EXPECTED TO BE 15:1 TO 20:1...POSSIBLY HIGHER. USING
THE 12Z NAM QPF AND EXPECTED SNOW RATIOS...INDICATE 12Z WED-12Z
THU SNOW TOTALS OF 10-13 INCHES ACROSS NW MN...7-10 INCHES WC MN
INTO THE CENTRAL AND NORTHERN VALLEY...AND 4-7 INCHES SOUTHERN
VALLEY AND WEST OF THE VALLEY. AS WINDS INCREASE...THIS SHOULD AT
LEAST BREAK APART THE SNOWFLAKES AND DECREASE RATIOS A BIT...SO
WILL INCREASE SNOW TOTALS...BUT SOMEWHERE IN BETWEEN WHAT WE HAD
AND WHAT THE NAM INDICATES.
WILL ALSO NEED TO MONITOR WIND SPEEDS AND BLOWING SNOW POTENTIAL.
DID INCREASE WINDS A BIT BASED ON LATEST OBSERVATIONS COMPARED TO
THE GUIDANCE. AS TEMPERATURES GET COLDER THE SNOW WILL BE EASIER
TO BLOW AROUND...SO COULD BE CLOSE TO BLIZZARD CONDITIONS IN THE
MORE PRONE AREAS. HOWEVER...WIND SPEEDS NOT EXPECTED TO REACH
BLIZZARD CRITERIA (35 MPH)...SO THE WINTER STORM WARNING IS A VERY
GOOD PRODUCT.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 359 AM CST WED DEC 4 2013
WATER VAPOR LOOP INDICATED UPPER LEVEL TROUGH OVER THE PACIFIC
NORTHWEST WAS DIGGING AS JET MOVES DOWN WEST SIDE OF TROUGH. ALSO
UPPER LEVEL LOW NOTED OVER NORTHERN NV AND NORTHWEST SASK AND A
SHORT WAVE OVER SOUTHEAST MT. MT SHORT WAVE TO MOVE ACROSS THE
FORECAST AREA THIS AFTERNOON AND TONIGHT. PRECIPITABLE WATER WAS
UNDER HALF AN INCH AND IS FORECAST TO DECREASE TODAY AND TONIGHT.
THE MT SHORT WAVE WAS ESSENTIALLY AN OPEN WAVE AND CLOSES OFF AFTER
MOVING EAST OF THE AREA. INVERTED SURFACE TROUGH EXTENDS FROM
NORTHWEST MN INTO IA. INVERTED TROUGH TO SHIFT EAST TODAY. RADAR
SHOWED LIGHT SNOW ACROSS MUCH OF ND INTO ADJACENT PARTS OF MN AND
WAS MOVING NORTHEAST ABOUT 25 KNOTS.
INCREASED TEMPS COUPLE DEGREES FOR TODAY THROUGH FRI WITH CLOUD
COVER EXPECTED TO STAY AROUND. NO CHANGE TO THE WARNING. WILL KEEP
WARNING AS IS.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 359 AM CST WED DEC 4 2013
FOR SAT THROUGH TUE...IT LOOKS LIKE A VERY COLD PERIOD WITH HIGHS
NEAR OR BELOW ZERO...AND BITTERLY COLD OVERNIGHT LOWS. THERE WILL BE
A CHANCE FOR SOME LIGHT SNOW MAINLY SUNDAY INTO EARLY MONDAY...AHEAD
OF ANOTHER RE-ENFORCING ARCTIC FRONT AND COLDER AIR. NO MAJOR PRECIP
EVENTS EXPECTED THOUGH AS WE REMAIN DEEPLY ENTRENCHED IN ARCTIC AIR
THROUGH THE PERIOD...WITH DANGEROUS WIND CHILLS LIKELY AN ISSUE
ANYTIME THE WIND BLOWS SINCE IT WILL BE SO COLD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1241 PM CST WED DEC 4 2013
GENERAL TREND WILL BE LIGHT TO MODERATE SNOW WITHIN AND EAST OF
THE VALLEY THROUGH MID AFTN. THIS WILL RESULT IN VSBY FLUCTUATIONS
FROM ABOUT 1/2SM TO 2SM...DEPENDING ON INTENSITY. WILL SEE THE
VALLEY IMPROVE FIRST FOLLOWED BY TVF/BJI IN THE LATE AFTN. CIGS
WILL PREDOMINANTLY REMAIN IFR WITH BREAKS INTO THE MVFR RANGE. BY
THE TIME CIGS IMPROVE...WINDS WILL KICK AROUND TO THE NW AND BLSN
COULD BE A PROBLEM OVERNIGHT. NOT CONFIDENT ENOUGH ON TIMING ANY
GIVEN SITE GOING BELOW 1SM...SO WILL HOLD OFF ON BLSN RELATED
VSBYS BEYOND THE FIRST SIX HOURS. CIGS WILL GRADUALLY CLIMB INTO
THE MVFR RANGE BY MORNING HOWEVER THE NW WINDS AND BLSN WILL
CONTINUE THROUGH 18Z THU.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WARNING UNTIL 6 AM CST THURSDAY FOR NDZ006>008-
014>016-024-026>030-038-039-049-052>054.
MN...WINTER STORM WARNING UNTIL 6 AM CST THURSDAY FOR MNZ001>009-
013>017-022>024-027>032-040.
&&
$$
UPDATE...TG
SHORT TERM...HOPPES
LONG TERM...DK
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1032 AM CST WED DEC 4 2013
.UPDATE...
ISSUED AT 1032 AM CST WED DEC 4 2013
12Z NAM HAS COME IN WITH HIGHER QPF TOTALS FROM 12Z WED TO 12Z
THUR...AND THE 15Z RAP MOSTLY AGREES. THESE MODELS APPEAR TO BE
PICKING UP ON MESO-SCALE FORCING THAT THE GFS/ECMWF/SREF/GEM ARE
NOT INCLUDING. CURRENT RADAR IMAGERY WOULD APPEAR TO INDICATE AND
AREA OF STRONGER FORCING FROM SE NORTH DAKOTA INTO NORTHWEST
MINNESOTA...WHICH THE NAM/RAP SHOW IN THEIR QPF FIELDS. SNOW
RATIOS ARE EXPECTED TO BE 15:1 TO 20:1...POSSIBLY HIGHER. USING
THE 12Z NAM QPF AND EXPECTED SNOW RATIOS...INDICATE 12Z WED-12Z
THU SNOW TOTALS OF 10-13 INCHES ACROSS NW MN...7-10 INCHES WC MN
INTO THE CENTRAL AND NORTHERN VALLEY...AND 4-7 INCHES SOUTHERN
VALLEY AND WEST OF THE VALLEY. AS WINDS INCREASE...THIS SHOULD AT
LEAST BREAK APART THE SNOWFLAKES AND DECREASE RATIOS A BIT...SO
WILL INCREASE SNOW TOTALS...BUT SOMEWHERE IN BETWEEN WHAT WE HAD
AND WHAT THE NAM INDICATES.
WILL ALSO NEED TO MONITOR WIND SPEEDS AND BLOWING SNOW POTENTIAL.
DID INCREASE WINDS A BIT BASED ON LATEST OBSERVATIONS COMPARED TO
THE GUIDANCE. AS TEMPERATURES GET COLDER THE SNOW WILL BE EASIER
TO BLOW AROUND...SO COULD BE CLOSE TO BLIZZARD CONDITIONS IN THE
MORE PRONE AREAS. HOWEVER...WIND SPEEDS NOT EXPECTED TO REACH
BLIZZARD CRITERIA (35 MPH)...SO THE WINTER STORM WARNING IS A VERY
GOOD PRODUCT.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 359 AM CST WED DEC 4 2013
WATER VAPOR LOOP INDICATED UPPER LEVEL TROUGH OVER THE PACIFIC
NORTHWEST WAS DIGGING AS JET MOVES DOWN WEST SIDE OF TROUGH. ALSO
UPPER LEVEL LOW NOTED OVER NORTHERN NV AND NORTHWEST SASK AND A
SHORT WAVE OVER SOUTHEAST MT. MT SHORT WAVE TO MOVE ACROSS THE
FORECAST AREA THIS AFTERNOON AND TONIGHT. PRECIPITABLE WATER WAS
UNDER HALF AN INCH AND IS FORECAST TO DECREASE TODAY AND TONIGHT.
THE MT SHORT WAVE WAS ESSENTIALLY AN OPEN WAVE AND CLOSES OFF AFTER
MOVING EAST OF THE AREA. INVERTED SURFACE TROUGH EXTENDS FROM
NORTHWEST MN INTO IA. INVERTED TROUGH TO SHIFT EAST TODAY. RADAR
SHOWED LIGHT SNOW ACROSS MUCH OF ND INTO ADJACENT PARTS OF MN AND
WAS MOVING NORTHEAST ABOUT 25 KNOTS.
INCREASED TEMPS COUPLE DEGREES FOR TODAY THROUGH FRI WITH CLOUD
COVER EXPECTED TO STAY AROUND. NO CHANGE TO THE WARNING. WILL KEEP
WARNING AS IS.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 359 AM CST WED DEC 4 2013
FOR SAT THROUGH TUE...IT LOOKS LIKE A VERY COLD PERIOD WITH HIGHS
NEAR OR BELOW ZERO...AND BITTERLY COLD OVERNIGHT LOWS. THERE WILL BE
A CHANCE FOR SOME LIGHT SNOW MAINLY SUNDAY INTO EARLY MONDAY...AHEAD
OF ANOTHER RE-ENFORCING ARCTIC FRONT AND COLDER AIR. NO MAJOR PRECIP
EVENTS EXPECTED THOUGH AS WE REMAIN DEEPLY ENTRENCHED IN ARCTIC AIR
THROUGH THE PERIOD...WITH DANGEROUS WIND CHILLS LIKELY AN ISSUE
ANYTIME THE WIND BLOWS SINCE IT WILL BE SO COLD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 702 AM CST WED DEC 4 2013
IFR CONDITIONS WERE ACROSS MUCH OF EASTERN ND WITH LOW VISIBILITIES
DUE TO SNOW. CIGS RISE TO 7 THOUSAND FT OVER THE FAR NORTHEAST
ZONES. EXPECT LOW CIGS TO SHIFT NORTHEAST THIS MORNING AS SNOW MOVES
NORTHEAST. WINDS WERE HIGHEST OVER THE WESTERN ZONES AND SHOULD
INCREASE THROUGH THE DAY. WINDS WILL REMAIN BRISK OVERNIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WARNING UNTIL 6 AM CST THURSDAY FOR NDZ006>008-
014>016-024-026>030-038-039-049-052>054.
MN...WINTER STORM WARNING UNTIL 6 AM CST THURSDAY FOR MNZ001>009-
013>017-022>024-027>032-040.
&&
$$
UPDATE...TG
SHORT TERM...HOPPES
LONG TERM...DK
AVIATION...HOPPES
AREA FORECAST DISCUSSION
NWS TULSA OK
1137 PM CST TUE DEC 3 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
HIGHLY VARIABLE FLIGHT CONDITIONS WILL BE SEEN OVERNIGHT INTO
EARLY WEDNESDAY MORNING DUE TO PATCHY FOG. MOST LOCATIONS WILL
LIKELY SEE AT LEAST OCCASIONAL PERIODS OF MVFR OR LOWER
VISIBILITIES...WITH KBVO AND KFSM MOST LIKELY TO SEE PROLONGED
PERIODS OF IFR/LIFR CONDITIONS. FOG WILL LIFT AND ALL LOCATIONS
WILL BECOME VFR BY LATE MORNING WEDNESDAY...WITH KFSM LIKELY BEING
THE LAST TO IMPROVE. WINDS WILL SHIFT TO THE NORTHWEST WEDNESDAY
AS A COLD FRONT MOVES ACROSS THE AREA.
&&
.PREV DISCUSSION... /ISSUED 859 PM CST TUE DEC 3 2013/
..UPDATE...
DISCUSSION...
PATCHY DENSE FOG IS BEGINNING TO DEVELOP ACROSS EASTERN OKLAHOMA
AND WESTERN ARKANSAS AS EXPECTED. THE CURRENT FORECAST REMAINS ON
TRACK AND WILL NOT BE UPDATED THIS EVENING.
PREV DISCUSSION... /ISSUED 535 PM CST TUE DEC 3 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
FOG IS ONCE AGAIN THE MAIN CONCERN TONIGHT. IT IS LIKELY THAT ALL
SITES WILL SEE IFR TO LIFR VISIBILITIES AGAIN IN FOG OVERNIGHT
INTO EARLY WEDNESDAY MORNING. VEERING SURFACE WINDS JUST AHEAD OF
A COLD FRONT WILL HELP SCOUR OUT THE FOG WEDNESDAY MORNING...WITH
VFR CONDITIONS AT ALL SITES BY MIDDAY. WINDS WILL SHIFT TO THE
NORTHWEST AT THE EASTERN OKLAHOMA SITES BEHIND THE COLD FRONT
WEDNESDAY.
PREV DISCUSSION... /ISSUED 352 PM CST TUE DEC 3 2013/
DISCUSSION...
WOW FOLKS...WHAT A FORECAST TODAY. THERE WILL BE SEVERAL ROUNDS OF
WINTRY PRECIPITATION THAT WILL HAVE IMPACTS ON TRAVEL AND POSSIBLY
THE POWER GRID AS WELL. I WILL DIVE INTO EACH FACET OF THE
FORECAST BELOW...ONE BY ONE.
FIRST...OF SOMEWHAT LESS IMPORTANCE...WILL BE FOG POTENTIAL
TONIGHT. FOR THE PAST 2 DAYS WE`VE HAD WIDESPREAD DENSE FOG.
TONIGHT...WHAT I SEE THAT IS DIFFERENT WILL BE THE DEPTH OF THE
NEAR GROUND MOIST LAYER. MODEL MOISTURE PROFILES DRY OUT FROM TOP
TO BOTTOM WITH TIME TONIGHT...ALTHOUGH THERE MAY BE ENOUGH REMNANT
MOISTURE NEAR THE GROUND FOR SOME PATCHY FOG DEVELOPMENT...SOME
POSSIBLY DENSE. FWIW...THE HRRR BREAKS OUT DENSE FOG OVER A GOOD
PORTION OF EASTERN OK THIS EVENING...AND IT HAS BEEN HANDLING THE
FOG WELL THE PAST 2 NIGHTS.
NOW TO THE MEAT OF THIS FORECAST. A VERY AMPLIFIED UPPER PATTERN
IS EVOLVING OVER THE WESTERN CONUS AS I TYPE...WITH A RIDGE NOSING
WELL UP INTO ALASKA...AND A DEEP POSITIVE TILT DOWNSTREAM TROUGH
DEVELOPING OVER THE WESTERN CONUS. THIS HAS CREATED A CROSS-POLAR
FLOW CLEAR FROM SIBERIA DOWN INTO NORTH AMERICA. WORSE YET...THIS
PATTERN WILL LIKELY PERSIST FOR ABOUT A WEEK...SENDING SHOT AFTER
SHOT OF ARCTIC AIR DOWN INTO THE CONUS AS DISTURBANCES ROTATE
AROUND THE POLAR VORTEX OVER CENTRAL CANADA. THE INITIAL SURGE OF
ARCTIC AIR WILL ARRIVE TOMORROW...AND WILL UNDERCUT A STRONG BELT
OF SW FLOW ALOFT DOWNSTREAM FROM THE WESTERN TROUGH. THE FIRST
ROUND OF PRECIP WILL BE FORCED MAINLY BY LOW TO MID LVL
FRONTOGENESIS...WHICH WILL KICK IN BY EARLY THURSDAY. THE MODELS
ARE IN VERY GOOD AGREEMENT ON A RATHER IMPRESSIVE BAND OF PRECIP
FROM SE OK UP INTO NRN AR ON THURSDAY. NE OK WILL BE ON THE FRINGE
OF THE BEST FN FORCING...AND WILL SEE LIGHTER PRECIP AMOUNTS AS A
RESULT. IN FACT...PORTIONS OF OSAGE COUNTY MAY NOT SEE ANYTHING
WITH THIS FIRST ROUND. NAM/GFS TEMP PROFILES SUGGEST THAT A BAND
OF SIGNIFICANT ICING IS POSSIBLE FROM SE OK UP INTO W CNTRL AR AND
PORTIONS OF NW AR. SOME PLACES HERE MAY PICK UP A QUARTER INCH OR
MORE OF ICE ACCUMULATION...WHICH COULD CAUSE POWER OUTAGES AND
SIGNIFICANT TRAVEL ISSUES. A BAND OF SIGNIFICANT SLEET
ACCUMULATION IS POSSIBLE JUST NORTH OF WHERE THE ZR/IP LINE SETS
UP...MOST LIKELY FROM E CNTRL AND EVENTUALLY PORTIONS OF SE OK
INTO W CNTRL AND NW AR AS THE COLDER AIR GETS DEEPER WITH TIME
FROM NORTH TO SOUTH. THIS COULD CAUSE SIGNIFICANT TRAVEL ISSUES AS
WELL. SOME LIGHT SNOW ACCUMULATION IS MOST LIKELY NEAR THE KANSAS
BORDER. THE FN FORCING SHIFTS SOUTHEAST BY THURSDAY EVENING AND
WEAKENS OVER OUR AREA...ENDING THE FIRST ROUND OF PRECIP.
ROUND TWO BEGINS LATE THURSDAY NIGHT INTO FRIDAY...AS A SHORTWAVE
TROUGH EJECTS EAST FROM THE WESTERN TROUGH OVER THE PLAINS. THE
INCREASING QG FORCING WILL BE MORE BROAD AND WILL COVER MORE OF
THE FORECAST AREA THIS GO AROUND. MODELS SUGGEST THAT A NICE WSW-
ENE ORIENTED DEFORMATION ZONE WILL SET UP FROM SOUTH CENTRAL INTO
NORTHEAST OK AND NORTHWEST AR. LAYER TEMP PROFILES FORECAST BY THE
GFS/ECMWF SUGGEST SNOW OR SNOW/SLEET FOR NE OK AND NW AR...WITH
MORE SLEET ACROSS MUCH OF SE OK AND W CNTRL AR. BASED ON QPF...THIS
COULD LEAD TO SEVERAL INCHES OF SNOW/SLEET ACCUMULATION.
HOWEVER...THE WARM NOSE MAY BE STRONG ENOUGH FOR MORE ZR AND THUS
ICE ACCUMULATION ACROSS FAR SE OK INTO W CNTRL AR LATE THURSDAY
NIGHT AS ROUND TWO GETS GOING. BY FRIDAY MORNING...THE WARM LAYER
IS ERODED ENOUGH FROM THE NORTH TO SHIFT THE BEST ICE POTENTIAL
SOUTH AND EAST OF THE FORECAST AREA. BOTH THE GFS/ECMWF SUGGEST
THAT THE QG FORCING WILL SHUT OFF RAPIDLY BY MIDDAY FRIDAY AS THE
WAVE SHEARS OUT AND LIFTS NORTHEAST OVER THE PLAINS. ROUND TWO
WILL LIKELY BRING MORE TRAVEL HEADACHES ACROSS A LARGER PORTION OF
THE FORECAST AREA. POWER INTERRUPTIONS EITHER MAY DEVELOP OR
CONTINUE OVER AREAS THAT HAVE RECEIVED THE MOST ICE ACCUMULATION
FROM THESE FIRST TWO ROUNDS OF PRECIP.
ROUND THREE GETS GOING OVER THE WEEKEND...AS ANOTHER SHORTWAVE
EMBEDDED WITHIN THE WESTERN CONUS LONGWAVE TROUGH EJECTS NORTHEAST
OVER THE PLAINS...AND A BIT FARTHER NORTH THAN THE PREVIOUS WAVE.
IN ADDITION...WITH THE SURFACE FRONT AND BEST MOISTURE NOW SHUNTED
WELL TO OUR SOUTH AND EAST...THERE WILL NOT BE AS MUCH MOISTURE
FOR THIS SYSTEM TO WORK WITH. INCREASING LOW/MID LVL ISENTROPIC
LIFT WILL RESULT IN AT LEAST LIGHT AMOUNTS OF PRECIPITATION
BEGINNING LATE SATURDAY AND INTO SUNDAY. MODEL SOUNDINGS ARE
FAIRLY DRY OVERALL IN THE CRUCIAL -10 TO -15C LAYER...WITH
MOISTURE MAINLY CONFINED BELOW 700MB. THIS WOULD SUGGEST THAT
PATCHY FREEZING DRIZZLE IS A POSSIBILITY AND HAS THUS BEEN ADDED
TO THE GRIDS. THERE ARE SOME HINTS OF PERIODIC MOISTENING DEEP
ENOUGH FOR ICE PRODUCTION...SO I HAVE ELECTED TO USE MULTIPLE
PRECIP TYPES IN THE GRIDS. THE GFS/ECMWF SUGGEST THAT THE WARM LAYER
WILL EXPAND NORTH INTO OUR AREA SOME DURING THIS TIME...AND THUS
ANOTHER ROUND OF MIXED PRECIP IS POSSIBLE...HOWEVER I WILL
REITERATE THAT PRECIP SHOULD REMAIN LIGHT OVERALL. THIS ROUND OF
PRECIP SHOULD END BY SUNDAY EVENING AS THE WARM CONVEYOR AND
RESULTING ISENTROPIC LIFT SHIFTS EAST OF OUR AREA.
FINALLY...BY EARLY NEXT WEEK THE GFS/ECMWF ARE IN GOOD AGREEMENT
THAT THE PERSISTENT WESTERN LONGWAVE TROUGH WILL LIFT OUT AND SHIFT
EAST OVER THE PLAINS. SOME LIFT AND LIMITED MOISTURE COULD SQUEEZE
OUT SOME LIGHT SNOW ON MONDAY. THIS SHOULD END WINTER PRECIP
CHANCES FOR THE TIME BEING...WHEW.
BOTTOM LINE...AN EXTENDED PERIOD OF VERY COLD WEATHER ALONG WITH
SEVERAL ROUNDS OF WINTRY PRECIPITATION ARE EXPECTED. TRAVEL WILL
BE AFFECTED...AND POWER DELIVERY MAY BE AS WELL IN SOME AREAS.
LOWS ON SATURDAY AND TUESDAY MORNING ARE EXPECTED TO DIP DOWN INTO
THE SINGLE DIGITS WITH WIND CHILLS BELOW ZERO OVER PORTIONS OF THE
AREA. GET READY FOLKS.
THE WINTER STORM WATCH WILL BE CONTINUED FOR THE ENTIRE FORECAST
AREA...WITH WARNINGS LIKELY TO FOLLOW EITHER TONIGHT OR WEDNESDAY.
LACY
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WINTER STORM WATCH FROM 6 AM THURSDAY TO 6 PM FRIDAY FOR OKZ054-
OKZ055-OKZ056-OKZ057-OKZ058-OKZ059-OKZ060-OKZ061-OKZ062-
OKZ063-OKZ064-OKZ065-OKZ066-OKZ067-OKZ068-OKZ069-OKZ070-
OKZ071-OKZ072-OKZ073-OKZ074-OKZ075.
WINTER STORM WATCH FROM NOON THURSDAY TO 6 PM FRIDAY FOR OKZ049-
OKZ053-OKZ076.
AR...WINTER STORM WATCH FROM 6 AM THURSDAY TO 6 PM FRIDAY FOR ARZ001-
ARZ002-ARZ010-ARZ011-ARZ019.
WINTER STORM WATCH FROM NOON THURSDAY TO 6 PM FRIDAY FOR ARZ020-
ARZ029.
&&
$$
AVIATION...05
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1040 PM EST THU DEC 5 2013
.SYNOPSIS...
A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE
TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TONIGHT THROUGH
FRIDAY...BRINGING PERIODS OF MIXED PRECIPITATION TO THE AREA. HIGH
PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE RECENTLY ACTIVE EARLY
SEASON WINTER WEATHER PATTERN ON SATURDAY. CONFIDENCE IS STEADILY
INCREASING FOR A PERIOD OF FROZEN AND FREEZING PRECIPITATION
SUNDAY INTO EARLY MONDAY THAT SHOULD EVENTUALLY CHANGE TO RAIN. AN
ARCTIC FRONTAL PASSAGE EARLY NEXT WEEK WILL DROP TEMPERATURES WELL
BELOW NORMAL THROUGH NEXT WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
FINE LINE ON KCCX RADAR SHOWING LOCATION OF COLD FRONT...JUST WEST
OF KUNV AND KAOO AT 0330Z. NEAR TERM MODELS AGREE IN TRACKING
COLD FRONT SE ACROSS THE AREA OVERNIGHT.
ALTHOUGH RAIN TAPERED OFF A BIT ACROSS CENTRAL PA EARLIER THIS
EVENING...REGIONAL RADAR MOSAIC SHOWING ANOTHER BATCH OF RAIN
APPROACHING FROM WESTERN PA AT 0330Z. UPSTREAM WATER VAPOR LOOP
SHOWS A SHORTWAVE OVR ILLINOIS AT 03Z...WHICH SHOULD LIFT NE
ACROSS THE E GRT LKS OVERNIGHT. LG SCALE FORCING AHEAD OF THIS
FEATURE SHOULD HELP SUPPORT NEXT BATCH OF PRECIP LATE THIS EVENING
THRU ARND 10Z. 02Z RAP FRONTOGENESIS PATTERNS MATCH WELL WITH
BAND OF SNOW FALLING FROM CENTRAL INDIANA TO NW OHIO. RAP INDICATES
THIS BAND OF ENHANCED FGEN LIFTS ACROSS NW PA BTWN 06Z-09Z AS MDL
SOUNDINGS BECOME COLD ENOUGH FOR SNOW. SO...BELIEVE A LIGHT SNOW
ACCUM IS POSSIBLE OVR WARREN/MCKEAN COS LATE TONIGHT.
FURTHER SOUTH...WILL RAMP UP CHC OF RAIN OVERNIGHT...AS SHORTWAVE
AND ASSOC LL JET/PLUME OF ANOMALOUS PWATS LIFTS THRU. BLEND OF
LATEST LAMP/RAP/NAM INDICATE TEMPS BEHIND CDFRONT WILL COAST
DOWNWARD TO THE U20S BY DAWN OVR THE NW MTNS...THE 30S MOST OF
CENTRAL PA...AND THE M40S ACROSS THE LOWER SUSQ VALLEY.
HAVE INCREASED WSPEEDS OVERNIGHT BASED ON UPSTREAM REPORTS AND
BUFKIT SOUNDINGS...WHICH SUPPORT A PERIOD OF GUSTS ARND 20KTS IN
IN THE NW FLOW IN WAKE OF FRONTAL PASSAGE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
NEXT SHORTWAVE LIFTING OUT OF THE S PLAINS WILL SPAWN A WAVE OF
LOW PRESSURE ALONG QUASI-STATIONARY SFC FRONT S OF PA ON FRIDAY
WITH ANOTHER SLUG OF PRECIP FOR FRIDAY AFTERNOON AND EVENING.
STRONG FRONTOGENETIC FORCING WILL DEVELOP UNDER THE ENTRANCE
REGION OF A VERY STRONG JET STREAK THAT WILL RACE DOWN THE ST
LAWRENCE RIVER VALLEY. THE BIGGEST ISSUE WITH THE SECOND WAVE WILL
BE THE AMOUNT OF WINTRY WEATHER ASSOCIATED. LATEST ENSEMBLE AND
OPER GUIDANCE SUGGESTS AIR MASS WILL BE COLD ENOUGH TO SUPPORT
SNOW ACROSS THE N COUNTIES...AS THE HEAVIEST PRECIP ARRIVES FRIDAY
AFTN. FURTHER SOUTH...LATEST MDL SOUNDINGS SUPPORT RAIN CHANGING
TO A WINTRY MIX ACROSS THE CENTRAL COUNTIES FRIDAY EVENING...AND
MAINLY RAIN OVER ABOUT THE SERN 1/3 OR SO OF MY FCST AREA.
BLENDED MDL QPF SUPPORTS A 3-5 INCH SNOWFALL ACROSS THE N
TIER...WITH JUST ENUF OF A WINTRY MIX OVER THE CENTRAL COUNTIES
TO POTENTIALLY CREATE SLIPPERY ROADS DURING THE EVENING. ACROSS
THE LAUREL HIGHLANDS...WARM AIR ALOFT SHOULD PRECLUDE MUCH SNOW.
HOWEVER...THE HIGHER TERRAIN DOWN THERE STILL LOOKS SUSCEPTIBLE TO
A PERIOD OF FZRA FRIDAY EVENING. HAVE THEREFORE...MOVED BACK THE
START TIME OF THEIR ADVISORY TO 22Z.
DEEPENING COLD AIR WILL ADVECT INTO THE STATE LATE FRIDAY NIGHT WITH
LINGERING LIGHT SNOW/MIXED PRECIP TAPERING OFF QUICKLY ARND
MIDNIGHT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE OVER THE UPPER MIDWEST
SATURDAY WILL MIGRATE EASTWARD INTO THE NORTHERN MID-ATLANTIC
STATES BY SUNDAY MORNING...SETTING THE STAGE FOR WHAT APPEARS TO
BE A CLASSIC OVERRUNNING MIXED PRECIP EVENT FOR LATER SUNDAY INTO
MONDAY.
05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES
INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING
FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS.
THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN
CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES
SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN
NEW ENGLAND.
DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH
THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM
AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A
BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR
ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN
LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS
MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG
AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES
VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY
AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM
ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS
AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION
MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW
INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD
FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE
LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA.
WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE
IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING
ASSUMING MOD-HVY ICING VIA FZRA.
IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE
REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW
NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD
CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW
COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE
INTO SW NY.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
REGIONAL ANALYSIS CONTINUES TO SHOW WIDESPREAD MVFR/IFR
CONDITIONS DUE TO RAIN AND LOW CIGS...WITH LIFR OVER THE LOWER
SUSQ TERMINALS WHERE FOG IS STILL LOCALLY DENSE. IMPROVEMENT WILL
BE PAINFULLY SLOW TODAY...WITH CURRENT FLYING CONDITIONS ONLY
HOPING TO IMPROVE TO MVFR AT BEST AS RAIN ASSOCIATED WITH THE
FRONT MOVES INTO THE REGION.
MVFR AND LOWER FLIGHT CATEGORIES WILL CONTINUE INTO FRIDAY AS MORE
RAIN...SNOW...AND WINTRY MIX OVERSPREAD THE REGION.
OUTLOOK...
FRI...MVFR IN RAIN SE. IFR IN SNOW/WINTRY MIX NW.
SAT...MVFR SNOW SHOWERS IN THE MOUNTAINS. VFR IN CENTRAL/EASTERN
AREAS.
SUN...REDUCTIONS DEVELOPING WITH APPROACHING STORM THAT WILL BRING
A WINTRY MIX SPREADING SOUTH TO NORTH INTO SUN NIGHT.
MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 1 PM FRIDAY TO 5 AM EST SATURDAY
FOR PAZ004>006-010>012-017-018-037-041-042.
WINTER WEATHER ADVISORY FROM 5 PM FRIDAY TO 5 AM EST SATURDAY
FOR PAZ024-033.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LA CORTE/STEINBUGL
LONG TERM...STEINBUGL
AVIATION...LA CORTE/COLBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1002 PM EST THU DEC 5 2013
.SYNOPSIS...
A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE
TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TONIGHT THROUGH
FRIDAY...BRINGING PERIODS OF MIXED PRECIPITATION TO THE AREA. HIGH
PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE RECENTLY ACTIVE EARLY
SEASON WINTER WEATHER PATTERN ON SATURDAY. CONFIDENCE IS STEADILY
INCREASING FOR A PERIOD OF FROZEN AND FREEZING PRECIPITATION
SUNDAY INTO EARLY MONDAY THAT SHOULD EVENTUALLY CHANGE TO RAIN. AN
ARCTIC FRONTAL PASSAGE EARLY NEXT WEEK WILL DROP TEMPERATURES WELL
BELOW NORMAL THROUGH NEXT WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
FINE LINE ON KCCX RADAR SHOWING LOCATION OF COLD FRONT...FROM
KELM-KFIG-KJST AT 02Z. NEAR TERM MODELS AGREE IN TRACKING COLD
FRONT SE ACROSS THE AREA OVERNIGHT.
ALTHOUGH RAIN HAS TAPERED OFF A BIT ACROSS CENTRAL PA THIS
EVENING...UPSTREAM WATER VAPOR LOOP SHOWS A SHORTWAVE OVR ILLINOIS
AT 02Z...WHICH SHOULD LIFT NE ACROSS THE E GRT LKS OVERNIGHT. LG
SCALE FORCING AHEAD OF THIS FEATURE SHOULD HELP SUPPORT NEXT BATCH
OF PRECIP LATE THIS EVENING THRU ARND 10Z. 01Z RAP FRONTOGENESIS
PATTERNS MATCH WELL WITH BAND OF SNOW FALLING FROM CENTRAL INDIANA
TO NW OHIO. RAP INDICATES THIS BAND OF ENHANCED FGEN LIFTS ACROSS
NW PA BTWN 06Z-09Z AS MDL SOUNDINGS BECOME COLD ENOUGH FOR SNOW.
SO...BELIEVE A LIGHT SNOW ACCUM IS POSSIBLE OVR WARREN/MCKEAN COS
LATE TONIGHT.
FURTHER SOUTH...WILL RAMP UP CHC OF RAIN OVERNIGHT...AS SHORTWAVE
AND ASSOC LL JET/PLUME OF ANOMALOUS PWATS LIFTS THRU. BLEND OF
LATEST LAMP/RAP/NAM INDICATE TEMPS BEHIND CDFRONT WILL COAST
DOWNWARD TO THE U20S BY DAWN OVR THE NW MTNS...THE 30S MOST OF
CENTRAL PA...AND THE M40S ACROSS THE LOWER SUSQ VALLEY.
HAVE INCREASED WSPEEDS OVERNIGHT BASED ON UPSTREAM REPORTS AND
BUFKIT SOUNDINGS...WHICH SUPPORT A PERIOD OF GUSTS ARND 20KTS IN
IN THE NW FLOW IN WAKE OF FRONTAL PASSAGE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
NEXT SHORTWAVE LIFTING OUT OF THE S PLAINS WILL SPAWN A WAVE OF
LOW PRESSURE ALONG QUASI-STATIONARY SFC FRONT S OF PA ON FRIDAY
WITH ANOTHER SLUG OF PRECIP FOR FRIDAY AFTERNOON AND EVENING.
STRONG FRONTOGENETIC FORCING WILL DEVELOP UNDER THE ENTRANCE
REGION OF A VERY STRONG JET STREAK THAT WILL RACE DOWN THE ST
LAWRENCE RIVER VALLEY. THE BIGGEST ISSUE WITH THE SECOND WAVE WILL
BE THE AMOUNT OF WINTRY WEATHER ASSOCIATED. LATEST ENSEMBLE AND
OPER GUIDANCE SUGGESTS AIR MASS WILL BE COLD ENOUGH TO SUPPORT
SNOW ACROSS THE N COUNTIES...AS THE HEAVIEST PRECIP ARRIVES FRIDAY
AFTN. FURTHER SOUTH...LATEST MDL SOUNDINGS SUPPORT RAIN CHANGING
TO A WINTRY MIX ACROSS THE CENTRAL COUNTIES FRIDAY EVENING...AND
MAINLY RAIN OVER ABOUT THE SERN 1/3 OR SO OF MY FCST AREA.
BLENDED MDL QPF SUPPORTS A 3-5 INCH SNOWFALL ACROSS THE N
TIER...WITH JUST ENUF OF A WINTRY MIX OVER THE CENTRAL COUNTIES
TO POTENTIALLY CREATE SLIPPERY ROADS DURING THE EVENING. ACROSS
THE LAUREL HIGHLANDS...WARM AIR ALOFT SHOULD PRECLUDE MUCH SNOW.
HOWEVER...THE HIGHER TERRAIN DOWN THERE STILL LOOKS SUSCEPTIBLE TO
A PERIOD OF FZRA FRIDAY EVENING. HAVE THEREFORE...MOVED BACK THE
START TIME OF THEIR ADVISORY TO 22Z.
DEEPENING COLD AIR WILL ADVECT INTO THE STATE LATE FRIDAY NIGHT WITH
LINGERING LIGHT SNOW/MIXED PRECIP TAPERING OFF QUICKLY ARND
MIDNIGHT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE OVER THE UPPER MIDWEST
SATURDAY WILL MIGRATE EASTWARD INTO THE NORTHERN MID-ATLANTIC
STATES BY SUNDAY MORNING...SETTING THE STAGE FOR WHAT APPEARS TO
BE A CLASSIC OVERRUNNING MIXED PRECIP EVENT FOR LATER SUNDAY INTO
MONDAY.
05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES
INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING
FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS.
THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN
CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES
SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN
NEW ENGLAND.
DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH
THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM
AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A
BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR
ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN
LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS
MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG
AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES
VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY
AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM
ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS
AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION
MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW
INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD
FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE
LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA.
WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE
IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING
ASSUMING MOD-HVY ICING VIA FZRA.
IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE
REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW
NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD
CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW
COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE
INTO SW NY.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
REGIONAL ANALYSIS CONTINUES TO SHOW WIDESPREAD MVFR/IFR
CONDITIONS DUE TO RAIN AND LOW CIGS...WITH LIFR OVER THE LOWER
SUSQ TERMINALS WHERE FOG IS STILL LOCALLY DENSE. IMPROVEMENT WILL
BE PAINFULLY SLOW TODAY...WITH CURRENT FLYING CONDITIONS ONLY
HOPING TO IMPROVE TO MVFR AT BEST AS RAIN ASSOCIATED WITH THE
FRONT MOVES INTO THE REGION.
MVFR AND LOWER FLIGHT CATEGORIES WILL CONTINUE INTO FRIDAY AS MORE
RAIN...SNOW...AND WINTRY MIX OVERSPREAD THE REGION.
OUTLOOK...
FRI...MVFR IN RAIN SE. IFR IN SNOW/WINTRY MIX NW.
SAT...MVFR SNOW SHOWERS IN THE MOUNTAINS. VFR IN CENTRAL/EASTERN
AREAS.
SUN...REDUCTIONS DEVELOPING WITH APPROACHING STORM THAT WILL BRING
A WINTRY MIX SPREADING SOUTH TO NORTH INTO SUN NIGHT.
MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 1 PM FRIDAY TO 5 AM EST SATURDAY
FOR PAZ004>006-010>012-017-018-037-041-042.
WINTER WEATHER ADVISORY FROM 5 PM FRIDAY TO 5 AM EST SATURDAY
FOR PAZ024-033.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LA CORTE/STEINBUGL
LONG TERM...STEINBUGL
AVIATION...LA CORTE/COLBERT
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
931 PM EST THU DEC 5 2013
.SYNOPSIS...
MOIST SOUTHWESTERLY FLOW OFF THE GULF OF MEXICO WILL PERSIST ACROSS
THE REGION BEFORE A COLD FRONT SLOWLY CROSSES THE FORECAST AREA
SATURDAY. CANADIAN HIGH PRESSURE WILL THEN BUILD IN FROM THE
NORTHEAST SUNDAY WITH MOIST SOUTHERLY FLOW ALOFT CONTINUING INTO
MONDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
900 PM UPDATE...SCT TO WIDESPREAD LIGHT RAIN CONTINUES TO STREAM
INTO THE AREA ON LLVL SW FLOW AHEAD OF SFC FRONT NOW OVER THE
CUMBERLAND PLATEAU. THE ACTIVITY SEEMS TO BE DUE TO GULF MOISTURE
PLUME OVERLAPPING WITH LARGER AREA OF LINGERING ISENTROPIC UPGLIDE.
UPSTREAM SHOWERS AND CONVECTIVE SEGMENTS OVER GA DO SHOW SIGNS OF
WEAKENING. CONVECTION ALLOWING MODELS GENERALLY ARE DOING A POOR JOB
OF REFLECTING THE CURRENT ACTIVITY. 00Z/01Z RAP IS BETTER BUT NOT
THAT GOOD. THE COMMON THREAD IN THESE AS WELL AS THE 00Z NAM IS THAT
PRECIP IS STILL SHOWN TO EVENTUALLY FOCUS ALONG THE ESCARPMENT
LEAVING THE PIEDMONT WITH LOW POPS AFTER MIDNIGHT. THAT STANDS TO
REASON AS WINDS WILL VEER AND ISENTROPIC LIFT DIMINISH...LEAVING THE
UPSLOPE MTN FLOW AS THE MAIN FORCING OVERNIGHT. KEPT THUNDER MENTION
IN THE SOUTHWEST PORTION OF THE FA WITH OCCASIONAL LIGHTNING BEING
SENSED...BUT INSTABILITY IS MINIMAL SO DID NOT EXPAND IT FROM THERE.
THOUGH STRONG 0-3KM SHEAR EVIDENT FROM PROG SOUNDINGS ANY
INSTABILITY WILL BE ABOVE INVERSION AND STORM ORGANIZATION OR SVR WX
IS VERY UNLIKELY AS A RESULT.
TEMPS HAVE RISEN IN THE WRN UPSTATE SINCE SUNSET AS SUGGESTED BY
AFTN RUN OF LOCAL WRF MODEL. TREND SHOULD BE SLIGHTLY UPWARD AS WAA
CONTINUES FURTHER NE INTO THE PIEDMONT BUT OVERALL TEMPS/DEWPTS
SHOULD BE NEAR STEADY THRU DAYBREAK.
AT 230 PM EST THURSDAY...A POSITIVELY TILTED UPPER
RIDGE WILL SLOWLY PUSH OFF THE EAST COAST TONIGHT AND FRIDAY...WHILE
A BROAD AND POSITIVELY TILTED UPPER TROUGH ADVANCES ACROSS CENTRAL
CANADA AND THE WESTERN HALF OF THE USA. THE TROUGH REMAINS
SUFFICIENTLY WEST OF THE APPALACHIANS TO KEEP SHORTWAVE ENERGY OVER
THE TN VALLEY.
WEAKENING ISENTROPIC UPGLIDE OVER DEPARTING HIGH PRESSURE WILL LOWER
PRECIPITATION CHANCES OVER THE PIEDMONT TONIGHT...WHILE INCREASING
SW LOW LEVEL FLOW PRODUCES A MARGINAL SW UPSLOPE FLOW COMPONENT INTO
THE SOUTHERN MOUNTAINS. THE GREATEST PRECIPITATION IS EXPECTED TO
FOCUS ALONG THE SOUTH FACING BLUE RIDGE...BUT AMOUNTS ARE NOT
EXPECTED TO BE EXCESSIVE. MODEST ELEVATED INSTABILITY WILL BE
PRESENT IN THE UPPER SAVANNAH RIVER VALLEY AND OVER THE
MOUNTAINS...BUT THE BETTER SHEAR WILL BE BENEATH THE UNSTABLE
LAYER...AND ORGANIZED CONVECTION IS NOT EXPECTED AT THIS TIME.
THE COLD FRONT WILL VERY SLOWLY MOVE INTO THE MOUNTAINS ON
FRIDAY...PROVIDING A FOCUS FOR PRECIPITATION...WHILE THE MODELS
SUGGEST A DECREASE IN MOISTURE OVER THE PIEDMONT IN THE WARM SECTOR.
VERY LIMITED ELEVATED INSTABILITY IS EXPECTED TO SPREAD INTO THE
FOOTHILLS AND PIEDMONT ON FRIDAY...AGAIN ABOVE THE BEST LOW LEVEL
SHEAR. AT THIS POINT NOTHING MORE THAN ISOLATED THUNDERSTORMS ARE
EXPECTED.
MINIMUM TEMPERATURES TONIGHT WILL RUN MORE THAN 20 DEGREES ABOVE
NORMAL TONIGHT IN WARM ADVECTION UNDER CLOUD COVER...WITH HEIGHTS
STILL ABOVE NORMAL. MAXIMUMS TEMPERATURE ON FRIDAY WILL RUN 15 OR
MORE DEGREES ABOVE NORMAL AS WARM ADVECTION OFFSETS FALLING HEIGHTS
ALOFT AND CLOUD COVER.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 230 PM EST THURSDAY...A COLD FRONT WILL MOVE INTO THE NC MTNS
FRIDAY EVENING. THE FRONT REPRESENTS THE LEADING EDGE OF AN ARCTIC
AIRMASS. AS IS TYPICAL WITH THIS TYPE OF AIRMASS IT WILL HAVE
TROUBLE MAKING IT ACROSS THE MOUNTAINS...THOUGH BY 12 UTC SATURDAY
IT SHOULD HAVE MOVED THROUGH MOST OF THE FORECAST AREA. THERE WILL
BE A NARROW RIBBON OF 300-500 J/KG CAPE VALUES ALONG THE
BNDRY...OVER THE SRN NC MTNS...FRIDAY EVENING. THE 0-3KM SHEAR
MAGNITUDE IS ON THE ORDER OF 40-50 KTS. WHILE THE RICHER BNDRY LAYER
AIR IS EXPECTED TO STAY A LITTLE TO THE SOUTH OF THE FORECAST
AREA...THESE PARAMETERS ARE SUFFICIENT TO SUPPORT A SMALL CHANCE OF
DAMAGING WINDS WITH ANY CONVECTION THAT MOVES INTO THE NC MTNS FRI
EVENING. FORTUNATELY...THE DEEP LAYER FORCING DOES NOT LOOK TO
SUPPORT ORGANIZED MCS ACTIVITY.
THE BAND OF PCPN ALONG THE FRONT BREAKS UP AND LARGELY GOES AWAY
LATE FRIDAY NIGHT AND SATURDAY. I/VE CUT BACK POPS INTO THE CHANCE
RANGE OVER MOST OF THE FA DURING THIS TIME...AND THAT MIGHT NOT BE
LOW ENOUGH. I/M CARRYING MAINLY CLOUDY SKIES ON SATURDAY...BUT THERE
IS A CHANCE THAT THE NRN ZONES WILL CLEAR UP FOR A WHILE IN THE
MORNING.
SATURDAY NIGHT AND SUNDAY ISENTROPIC UPGLIDE WILL DEVELOP OVER THE
WEDGE-RIDGE. THE 850-700 MB THICKNESSES ARE VERY WARM...THOUGH THE
1000-850 THICKNESS WILL BE LOW ENOUGH TO SUPPORT FREEZING RAIN OVER
PARTS OF THE NC BLUE RIDGE AND FOOTHILLS. THE SREF PLUME DIAGRAMS
SHOW OVER A HALF INCH OF FREEZING RAIN AT BOONE AND ABOUT 2 TENTHS
OF INCH OF ICE AT HICKORY. AS IS TYPICAL...THE GFS IS A LITTLE
WARMER. IT/S ALSO A LITTLE DRIER. IN FACT...THE AMOUNT OF PCPN THAT
THE GFS HAS OVER THE WEDGE WOULDN/T BE SUFFICIENT FOR DAMAGING ICE
ACCUMULATIONS WHILE THE NAM AND CANADIAN HAVE CLOSER TO A HALF INCH
OF LIQUID PCPN. THE ECMWF JUST CAME IN AND IT SUPPORTS THE LOWER
VALUES OF THE GFS. I/VE INCREASED THE AMOUNT OF FREEZING RAIN
CONSIDERABLY ALONG THE NC BLUE RIDGE...THE WRN FOOTHILLS AND THE
UPPER FRENCH BROAD VALLEY LATE SAT NIGHT AND SUNDAY MORNING. WE ARE
STILL DEALING WITH A LATE 5TH PERIOD AND 6TH PERIOD EVENT AND IT/S
WAY TOO EARLY TO ISSUE WATCHES. ALSO...THE UNUSUALLY WARM MID LEVEL
THICKNESSES AND THE GLOBAL MODEL/S RECENT TREND TOWARD LOWER QPF ADD
TO THE FORECAST UNCERTAINTY. HOWEVER...THE OVERALL TREND LOOKS TO
SUPPORT SOME AMOUNT OF FREEZING RAIN OVER OUR NRN ZONES EARLY
SUNDAY. AND IF THE HEAVIER QPF WERE TO VERIFY WE COULD EVEN SEE
DAMAGING ACCUMULATIONS OF ICE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 225 PM THURSDAY...PRETTY GOOD GUIDANCE AGREEMENT THRU THE
MEDIUM RANGE. AT LEAST UNTIL THE END OF THE PERIOD. SWLY FLOW STARTS
OUT OVER THE AREA AT THE BEGINNING OF THE PERIOD. SOME SHORT WAVE
ENERGY MOVES THRU THE FLOW AND OVER THE AREA THRU MON NITE. THE
ECMWF SWINGS A TROF ACROSS THE AREA TUE WITH NEARLY ZONAL FLOW
SETTING UP FOR WED. IN THEN BRINGS A DEVELOPING SRN STREAM UPPER LOW
TOWARD THE AREA THU. THE GFS BRINGS THE UPPER TROF TOWARD THE AREA
TUE...SHEARS IT OUT OVER THE AREA WED...THEN BLOWS A DAMPENED UPPER
TROF ACROSS THE AREA THU. AT THE SFC...THE WET WX CONTINUES FOR THE
EARLY PERIODS. THE CAD OVER THE AREA ERODES SUN NITE AS THE MILLER B
LOWS MOVE WELL NORTH OF THE AREA. STILL LOOKS LIKE A COLD...RAW AND
RAINY NITE WITH LIQUID RAIN THE ONLY P-TYPE. THE PRECIP CONTINUES
OVER THE AREA MONDAY AS A COLD FRONT SLIDES INTO THE AREA. THERE MAY
BE ENUF INSTABILITY FOR A T-STORM OR TWO OVER THE UPSTATE AND NE GA.
THE PRECIP LINGERS MON NITE AS THE FRONT ONLY SLOWLY SLIDES EWD...
THEN FINALLY ENDS FROM WEST TO EAST OVER THE AREA TUE AS DRY HIGH
PRESSURE BUILDS IN BEHIND THE SLOWLY MOVING FRONT. THERE COULD BE
ENUF COLD AIR BEHIND THIS SYSTEM FOR A MIX OR CHANGEOVER TO SNOW IN
THE HIGH ELEVATIONS OF THE NC MTNS. VERY LIGHT ACCUMS WOULD BE
POSSIBLE. THE FRONT THEN STALLS NEAR THE COAST AS WAVES OF LOW
PRESSURE MOVE ALONG THE FRONT. THE GFS KEEPS THE PRECIP EAST OF OUR
CWFA WHILE THE ECMWF BRINGS PRECIP BACK INTO THE AREA WITH A MILLER
A TYPE LOW AND ANOTHER CAD DEVELOPING. HAVE KEPT THE FCST DRY FOR
NOW GIVEN THE UNCERTAINTY.
LOWS SUN NITE SHOULD BE EARLY IN THE EVENING AS STRONG WAA TAKES
PLACE OVERNIGHT WITH HIGHS MONDAY AROUND 5 DEGREES ABOVE NORMAL.
LOWS MON NITE WILL BE COOLER OVER THE NC MTNS BUT WARMER ELSEWHERE.
A COOL DOWN BEGINS TUE WITH TEMPS FALLING BELOW NORMAL AND COOLING
EACH PERIOD.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
AT KCLT...LIFR CIGS ARE EXPECTED TO PERSIST TONIGHT EVEN AS LIFT
FROM WARM UPGLIDE WEAKENS THRU THE NIGHT...AND SOME GUIDANCE
SUGGESTS CIG RISING TO MVFR OR EVEN VFR. LLVL DRYING JUST LOOKS VERY
UNLIKELY WITH SLY FLOW CONTINUING. PERSISTENT BREEZE SHOULD MAINTAIN
MIXED SFC LAYER UNTIL AFTER MIDNIGHT ALLOWING CIG TO STAY AOA 003.
PRECIP CHANCES NONZERO BUT GENERALLY TOO LOW TO MENTION THIS
PERIOD...BUT INCLUDED A TEMPO FOR AN AREA OF PRECIP WHICH MAY MAKE
IT TO THE FIELD LATE EVENING. VSBY EXPECTED TO DROP TO LIFR
OVERNIGHT ESPECIALLY IF RA OCCURS. GUIDANCE IN PRETTY GOOD AGREEMENT
THAT CIGS LIFT TO VFR FRIDAY...WITH WINDS BECOMING GUSTY AS GRADIENT
TIGHTENS AHEAD OF COLD FRONT WHICH WILL BE ALONG THE APPALACHIANS.
ELSEWHERE...MOIST WARM UPGLIDE CONTINUES IN THE MTNS BUT WANES OVER
THE PIEDMONT TONIGHT. NONETHELESS...SITES THAT ARE IFR ARE NOT
EXPECTED TO SEE IMPROVEMENT UNTIL AFTER DAYBREAK FRIDAY WITHOUT A
MECHANISM TO INDUCE LLVL DRYING. WITH S TO SW FLOW...PRECIP CHANCES
GREATEST IN THE MTNS WHERE UPSLOPE ENHANCES WHAT IS LEFT OF THE
UPGLIDE REGIME. GUSTY SW WINDS ARE EXPECTED FRIDAY WITH PRESSURE
GRADIENT TIGHTENING AND CIGS MIXING UP TO MVFR OR LOW VFR.
OUTLOOK...A MOIST AND ACTIVE PATTERN WILL CONTINUE ACROSS THE REGION
THRU EARLY NEXT WEEK. RESTRICTIVE CEILINGS EACH NIGHT AND PERHAPS
WELL THRU THE DAYLIGHT HOURS...ESPECIALLY ACROSS THE MTNS CAN BE
EXPECTED.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT MED 68% MED 63% HIGH 82% HIGH 100%
KGSP HIGH 80% MED 68% MED 67% HIGH 91%
KAVL HIGH 86% HIGH 90% MED 77% HIGH 90%
KHKY HIGH 80% MED 76% LOW 55% MED 69%
KGMU HIGH 81% MED 72% LOW 57% HIGH 91%
KAND MED 74% MED 69% MED 69% MED 71%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.CLIMATE...
RECORD HIGH TEMPERATURES FOR FRIDAY DEC 6TH...
AVL...73 IN 1998
CLT...78 IN 1998
GSP...76 IN 1998
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...JAT/WIMBERLEY
SHORT TERM...MCAVOY
LONG TERM...RWH
AVIATION...WIMBERLEY
CLIMATE...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1113 PM CST TUE DEC 3 2013
.UPDATE...
ISSUED AT 945 PM CST TUE DEC 3 2013
MODELS CONTINUE TO HAVE DIFFICULTY WITH THE EVOLUTION OF TONIGHTS
SYSTEM. A LOT OF ENERGY DIVING SOUTHEAST INTO THE TROUGH...AND JUST HOW
MUCH AND WHEN THIS FORCING EJECTS EAST IS THE ISSUE. HRRR AND RAP
HAVE BEEN INCONSISTENT FROM RUN TO RUN AND THUS NOT OF MUCH USE WITH
THIS SYSTEM. RADAR TRENDS SHOW AN EXPANDING AREA OF MAINLY LIGHT SNOW
ALONG AND JUST SOUTH OF INTERSTATE 90...WITH AN EXPANDING AREA OF
MODERATE TO AT TIMES HEAVY SNOW IN NORTH CENTRAL NEBRASKA AND SOUTH
CENTRAL SOUTH DAKOTA. ACTIVITY SEEMS TO NOW BE EXPANDING NEAR THE 700
MB FRONT IN AN AREA OF BROAD ISENTROPIC LIFT AND INCREASING PV
ADVECTION. FRONTOGENESIS NOT AS WELL DEFINED IN LATEST MODEL
RUNS...SUGGESTING WE END UP SEEING A BIT OF A BROADER AREA OF
MODERATE SNOW. BASED ON RADAR TRENDS AND THE LATEST 0Z NAM...SEEMS
LIKE THIS AREA OF SNOW WILL TRACK A BIT NORTHWEST OF THE PREVIOUS
FORECAST...BUT NOT BY MUCH. AND BY AFTER MIDNIGHT...WOULD EXPECT THAT
LATTER AREA OF STEADY SNOW THAT IS CURRENTLY MOVING NORTHEAST...TO
BE FORCED MORE EASTERLY BY THE APPROACHING PV ANOMALY. THIS SHOULD
BRING THIS AREA OF SNOW THROUGH ALL THE COUNTIES CURRENTLY IN THE
HEADLINE. DID ADJUST POPS UPWARD IN THE MORNING TO ACCOUNT FOR THIS
SLOWER TIMING. ALSO WE STAY SATURATED THROUGH THE DAY...AND AS ONE
MORE PUSH OF LIFT MOVES ACROSS DURING THE LATE MORNING AND EARLY
AFTERNOON WE MAY VERY WELL SEE ANOTHER LITTLE BURST OF SNOW DROPPING
ANOTHER INCH OR SO...SORT OF LIKE THE 0Z NAM SHOWS.
STILL LOOKS LIKE A WIDESPREAD 3 TO 6 INCHES IN THE WARNING...WITH
ISOLATED HIGHER AMOUNTS AROUND 7 INCHES...ESPECIALLY IF RATIOS END
UP A BIT HIGHER OR IF WE DO SEE A BIT MORE ENHANCED BANDING. LATEST
TRENDS WOULD SUGGEST THE BEST CHANCE OF SEEING THESE HIGHER AMOUNTS
WILL BE FROM GREGORY TO MITCHELL TO MARHSALL...WITH AMOUNTS ON THE
LOWER SIDE OF THE RANGE AS YOU GET TO THE SOUTHEAST EDGE OF THE
WARNING. HEADLINES LOOK IN GOOD SHAPE...AND THUS NO CHANGES PLANNED.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 350 PM CST TUE DEC 3 2013
RELATIVE QUIET PERIOD FROM LATE MORNING INTO EARLY AFTERNOON IS
STARTING TO CHANGE AS LIFT FORCING SPREADS INTO SOUTH CENTRAL SOUTH
DAKOTA IN ADVANCE OF STRONG JET PUNCHING OUT OF THE CENTRAL ROCKIES.
STRONG FRONTOGENETIC FORCING WILL CONTINUE TO EXPAND ENE ALONG MID
LEVEL BOUNDARY THROUGH THE EVENING...AND SHOULD LEAD TO A QUICK
DEVELOPMENT OF SNOW BAND WITH LIFT AND SNOW GROWTH WELL COLLOCATED
IN PROFILES OF MAIN BAND. SHADED TOWARD A SOMEWHAT COOLER THERMAL
PROFILE OVERALL WITH WET BULB EFFECT AND SUPPORT OF EC/SREF. EVEN
WITH THIS...SHOULD BE WARM ENOUGH ALOFT FOR SOME ALTERNATE TYPES IN
TRANSITION AT ONSET...PROBABLY SLEET AND LIGHT FREEZING RAIN BEFORE
A CHANGE TO SNOW. SOME LIGHT ICE ACCUMULATIONS MENTIONED FOR AREAS
AROUND THE IOWA GREAT LAKES...WHERE LOW LEVEL COOL PUSH WILL BE IN
PROXIMITY TO THE LINGERING WARMER AIR ALOFT.
MAIN CHANGE IN THE FORECAST FROM THE MID TO LATE MORNING UPDATE WAS
TO INTRODUCE A WINTER STORM WARNING TO AREAS GENERALLY NORTH OF A
WINDOM TO SIOUX FALLS TO WAGNER LINE. STILL LOOKING AT A BROAD
BANDING OF 4 TO 6 INCHES SNOWFALL...WITH LOCALLY HEAVIER AMOUNTS.
HARD TO PINPOINT THE EXACT LOCATION OF THE HEAVIER BAND...THE
STRONGER REASON FOR UPGRADING TO THE WARNING WAS COMBINING THE
SNOWFALL WITH GUSTY WINDS OF 25 TO 35 MPH. STRONGEST WINDS WILL
FIRST DEVELOP ACROSS THE WESTERN CWA AFTER MIDNIGHT...AND EXPAND
EASTWARD AS LOW PRESSURE INTENSIFIES TO THE SOUTHEAST LATER TONIGHT
AND WEDNESDAY. WINDS WILL BE SLOW TO INCREASE IN THE FAR EAST WITH
BAGGY GRADIENT NEAR THE INVERTED TROUGH...BUT EVENTUALLY WILL
INCREASE AND CREATE PROBLEMS WITH STRONGER GRADIENT BY LATE DAY IN
SW MN. BLOWING SNOW SHOULD REDUCE VISIBILITIES TO AROUND A HALF MILE
AT TIMES...AND COULD BE BRIEFLY LOWER AT TIMES OF FALLING SNOW.
SNOWFALL NOW LOOKING A BIT MORE APT TO CONTINUE INTO WEDNESDAY
ACROSS THE AREA...BUT WILL SLOW UP FROM SOUTHWEST TO NORTHEAST AS
INVERTED TROUGH PULLS EAST...AND UPPER WAVE WANDERS SLOWLY NORTH OF
THE AREA. TEMPERATURES WILL BE IN STRONG SUPPORT OF ICE PROCESSES
DURING THE DAY...SO PERHAPS EVEN FAVORABLE FOR FLURRIES AFTER
MEASURABLE THREAT WANES.
OTHERWISE...SOME AREAS OF DENSE FOG CONTINUE THIS AFTERNOON ACROSS
SOUTHWEST MINNESOTA...AND SO NOT TO CONFUSE WITH OVERALL WINTER
SCENARIO...HAVE NOT ISSUED A SEPARATE ADVISORY ON THIS FEATURE.
THERE WILL LIKELY BE SOME PATCHES OF FREEZING DRIZZLE INTERSPERSED
WITH FLURRIES UNTIL STRONGER FORCING AND DEEPER MOISTURE SPREADS IN
BY THE EVENING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 350 PM CST TUE DEC 3 2013
ANY LIGHT SNOW WILL TAPER DOWN TO FLURRIES ON WEDNESDAY NIGHT AS THE
SYSTEM PULLS AWAY AND FORCING IS LOST. CONFINED ANY BLOWING SNOW IN
THE EVENING TO AREAS WHICH COULD ACTUALLY RECEIVE AT LEAST A TENTH
OF AN INCH OF SNOW...THOUGH WINDS WILL ONLY MARGINALLY DIMINISH
OVERNIGHT WITH A TIGHT GRADIENT REMAINING ACROSS THE REGION...SO
COULD SEE PATCHY BLOWING SNOW OVER OTHER AREAS. EVEN WITH COLD AIR
ADVECTION CONTINUING...TEMPERATURES WILL REMAIN SOMEWHAT IN CHECK ON
WEDNESDAY NIGHT WITH ABUNDANT CLOUD COVER AND THE ABOVE MENTIONED
WINDS...THOUGH READINGS WILL STILL DROP TO AROUND ZERO BY VERY EARLY
THURSDAY MORNING. WIND CHILLS OVERNIGHT WILL JUST MEET WIND CHILL
CRITERIA IN SOME AREAS...AND MAY HAVE TO DEAL WITH THAT AT SOME
POINT IN REGARD TO HEADLINES...BUT WITH THE CURRENT HEADLINES OUT
DID NOT WANT TO CONFUSE THE MATTER.
SURFACE HIGH PRESSURE BEGINS TO BUILD INTO THE REGION ON
THURSDAY...AND IT WILL REMAIN BREEZY IN A COLD AIR ADVECTION
REGIME...ALTHOUGH WINDS WILL SLOWLY TAPERING DOWN DURING THE DAY AS
THE GRADIENT RELAXES A BIT. NOT SURE HOW QUICKLY CLOUDS WILL
DECREASE DURING THE DAY...WITH BOTH THE NAM AND GFS HINTING AT
STRATUS LINGERING THROUGH THE DAY. IN LIGHT OF THAT AND WITH SNOW
COVER ACROSS THE AREA WENT ON THE LOW SIDE OF GUIDANCE WITH HIGHS
ONLY IN THE SINGLE DIGITS AND TEENS. BY THURSDAY NIGHT IT DOES LOOK
LIKE THERE SHOULD BE MORE CLEARING...THOUGH WINDS WILL NOT
COMPLETELY DROP OFF...REMAINING CLOSE TO 10 KTS. BECAUSE OF
THAT...AGAIN THINK THAT TEMPERATURES WILL NOT COMPLETELY BOTTOM
OUT...THOUGH WENT ON THE LOW SIDE OF GUIDANCE WITH LOWS FROM NEAR 10
BELOW IN THE NORTH TO NEAR ZERO IN THE FAR SOUTHEAST. IF WINDS WOULD
BECOME CALM THEN IT WILL BE COLDER THAN CURRENTLY FORECASTED.
BY FRIDAY...925 MB TEMPERATURES ARE PROGGED TO BE WELL INTO THE
NEGATIVE UPPER TEENS TO NEGATIVE LOWER 20S C...AND WENT BELOW
GUIDANCE WITH HIGHS IN THE SINGLE DIGITS. FRIDAY NIGHT IS SETTING UP
TO BE THE COLDEST NIGHT OF THE NEXT FEW AS THE HIGH PRESSURE AXIS
MOVES OVERHEAD AND WINDS BECOME NEARLY CALM. THE ONLY FLY IN THE
OINTMENT WILL BE THE POSSIBILITY OF INCREASING MID AND HIGH
CLOUDS...BUT WENT BELOW ALL BLEND GUIDANCE...AND AM STILL PROBABLY
TOO WARM AS MODEL RUNS ARE COLDER. AT THIS POINT...HAVE LOWS IN THE
MID TEENS BELOW ZERO TO THE SINGLE DIGITS BELOW.
IN THE EXTENDED...SATURDAY THROUGH TUESDAY...THE COLD AIR LOOKS TO
BE LOCKED IN THROUGH THE PERIOD. MODELS IN FAIRLY DECENT AGREEMENT
ON BRINGING A CHANCE OF SNOW TO THE AREA SOMETIME IN THE SUNDAY TIME
FRAME...AS A NORTHERN STREAM UPPER LEVEL TROUGH BEGINS TO DROP INTO
THE NORTHERN PLAINS AND A SOUTHERN STREAM WAVE EJECTS OUT OF THE
DESERT SOUTHWEST. A REINFORCING SHOT OF COLD AIR DROPS INTO THE
REGION FOR THE BEGINNING OF NEXT WEEK WITH THE PASSAGE OF THIS
SYSTEM...AND MODELS HINTING THAT IT COULD BE EVEN COLDER THAN THE
UPCOMING COLD SPELL...THOUGH WILL HAVE TO WATCH AS IT IS STILL
PRETTY FAR OUT. IN ANY EVENT...STAYED ON THE LOW SIDE OF GUIDANCE
THROUGH THE PERIOD WITH EXPECTED SNOW COVER. THIS WILL PLAY OUT TO
HIGHS SINGLE DIGITS AND TEENS AND LOWS A FEW DEGREES EITHER SIDE OF
ZERO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1113 PM CST TUE DEC 3 2013
BAND OF HEAVIER SNOW SLATED TO MOVE ACROSS NORTHWEST HALF OF THE
FORECAST AREA THROUGH EARLY-MID MORNING WEDNESDAY...MAINLY IN AREAS
NEAR/NORTH OF A LINE FROM WAGNER-SIOUX FALLS-WINDOM. VISIBILITY OF A
MILE OR LESS WILL BE DOMINANT IN THE HEAVIER SNOW BAND...WITH IFR TO
OCCASIONALLY MVFR VISIBILITY...ALONG WITH IFR-MVFR CEILINGS EXPECTED
ELSEWHERE THROUGH THE NIGHT. SPOTTY FREEZING RAIN/DRIZZLE WILL ALSO
BE POSSIBLE IN THE PRE-DAWN HOURS OVER NORTHWEST IOWA. AMOUNTS WILL
BE VERY LIGHT...BUT SLIGHT ICING COULD OCCUR. IN ADDITION TO FALLING
SNOW...AREAS OF BLOWING SNOW WILL CREATE ADDITIONAL REDUCTIONS IN
VISIBILITY AS NORTH-NORTHWEST WINDS INCREASE TO 15-20KT WITH GUSTS
OF 20-30KT THROUGH THE DAY.
SNOWFALL CONDITIONS WILL IMPROVE GRADUALLY FROM SOUTHWEST TO
NORTHEAST AFTER 12Z-15Z...THOUGH EXPECT MVFR CONDITIONS AT BEST...AS
SCATTERED LIGHT SNOW AND AREAS OF BLOWING SNOW DUE TO THE STRONG
WINDS CONTINUE INTO THE EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST WEDNESDAY NIGHT FOR
SDZ068-069.
WINTER STORM WARNING UNTIL MIDNIGHT CST WEDNESDAY NIGHT FOR
SDZ038>040-050-052>067.
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST WEDNESDAY NIGHT FOR
MNZ089-090.
WINTER STORM WARNING UNTIL MIDNIGHT CST WEDNESDAY NIGHT FOR
MNZ071-072-080-081-097-098.
IA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST WEDNESDAY NIGHT FOR
IAZ001-002.
NE...NONE.
&&
$$
UPDATE...CHENARD
SHORT TERM...CHAPMAN
LONG TERM...JM
AVIATION...JH
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
928 PM CST THU DEC 5 2013
.UPDATE...
UPDATE TO ISSUE A WIND ADVISORY FOR THE COASTAL COUNTIES.
&&
.DISCUSSION...
WIND SPEEDS HAVE INCREASED AND WIND ADVISORY CRITERIA HAS BEEN
MET ALONG THE COAST. A WIND ADVISORY WILL BE IN EFFECT THROUGH 4
AM FOR THE COASTAL COUNTIES.
CONCERN IS GROWING FOR WINTER PRECIP OVER THE NW ZONES TONIGHT.
TEMPS ARE GETTING DANGEROUSLY CLOSE TO FREEZING. JACKSONVILLE AND
PALASTINE ARE BOTH REPORTING SLEET. SFC DEW PTS CONTINUE TO DROP
AND AM CONCERNED ABOUT EVAPORATIVE COOLING LOWERING SFC TEMPS TO
NEAR OR JUST BELOW FREEZING. NAM 12 FCST SOUNDINGS SHOW SFC TEMPS
FALLING TO 32 DEGREES AT 09Z AND 31 DEGREES 12Z-18Z. THE NAM12 SFC
DEW PT FIELD IS WARMER SO THERE ARE CONFLICTING SIGNALS BETWEEN
SFC PARAMETERS AND SOUNDING PARAMETERS. AM STRONGLY CONSIDERING A
WINTER WEATHER ADVISORY FOR AREAS NW OF A CALDWELL TO CROCKETT
LINE FOR OVERNIGHT INTO FRI MORNING. 43
&&
.PREV DISCUSSION... /ISSUED 805 PM CST THU DEC 5 2013/
UPDATE...
SEE EVENING UPDATE.
DISCUSSION...
AT 01Z...A COLD FRONT EXTENDED FROM SOUTH CENTRAL LOUISIANA
ACROSS THE WESTERN GULF. A VERY TIGHT PRESSURE GRADIENT IS IN
PLACE AND WIND SPEEDS ARE APPROACHING ADVISORY CRITERIA. WILL
WATCH TRENDS BUT WILL HOLD OFF ON A WIND ADVISORY FOR THE COASTAL
COUNTIES FOR NOW. WATER TEMPS HAVE COOLED A BIT SINCE THE LAST
FROPA...SO FEEL THERMAL CONTRIBUTION TO WINDS WILL BE LESS THAN
PAST COUPLE OF EVENTS. RAP GUIDANCE ALSO SUGGESTS THAT WINDS WILL
REMAIN BELOW ADVISORY CRITERIA.
POPS ARE RATHER HIGH CONSIDERING THE RADAR LOOKS SO BENIGN AT THE
CURRENT TIME. 00Z 850 MB ANALYSIS SHOWS WINDS STILL OUT OF THE
SOUTH WITH AN 850 MB FRONT EXTENDING FROM TEXARKANA TO ABOUT
LAREDO. ISENTROPIC UPGLIDE HAS NOT REALLY KICKED IN YET AS NORTH
WINDS REMAIN VERY SHALLOW. THIS SHOULD CHANGE OVERNIGHT AS THE
850 MB FRONT CLEARS THE COAST. 00Z SOUNDINGS SHOW A SATURATED
LAYER FROM THE SURFACE TO 850 MB...AND VERY DRY AIR ABOVE THE
SATURATED LAYER. NAM12 AND RAP FORECAST SOUNDINGS CLOSELY MATCH
THE 00Z SOUNDINGS. THIS TYPE OF SOUNDING FAVORS DRIZZLE OVER RAIN.
EITHER WAY...EXPECT CONDS TO BECOME INCREASINGLY DAMP OVERNIGHT.
TEMP FCST LOOKS TO BE ON TRACK. NOT EXPECTING FREEZING TEMPS
OVERNIGHT BUT CALDWELL (RWV) IS GETTING CLOSE. CURRENT TEMP AT RWV
IS 34 DEGREES WITH A DEW PT OF 30. HAVE SOME CONCERN THAT DEW
POINTS NEAR 30 WILL ALLOW FOR SOME EVAPORATIVE COOLING ONCE PRECIP
BEGINS AND THEN INSTEAD OF DRIZZLE...WE GET FREEZING DRIZZLE.
WILL AGAIN WATCH TRENDS BUT FEEL CURRENT FCST HAS A GOOD HANDLE
ON TONIGHT`S TEMP/PRECIP TRENDS. HAVE MADE MINOR CHANGES TO THE
GRIDS. NEW ZFP OUT BY 900 PM. 43
PREV DISCUSSION... /ISSUED 523 PM CST THU DEC 5 2013/
DISCUSSION...
SEE THE 06Z AVIATION DISCUSSION BELOW.
40
AVIATION...
ISENTROPIC LIFT WILL HELP LOWER MVFR CONDITIONS TO IFR BY MID
EVENING. MODEL FORECAST SOUNDINGS AND THE NAM12 RAINFALL FORECAST
SHOW THAT RAIN IS MOST PROBABLE FRIDAY MORNING THROUGH THE MID
AFTERNOON PERIOD. WINDS WILL BE ANOTHER FACTOR...WITH GUSTY
CONDITIONS MOST LIKELY ALONG THE COAST THROUGH THE PERIOD...WHILE
MAINLY AFTER 13Z FRIDAY OVER THE INLAND SITES.
40
PREV DISCUSSION... /ISSUED 346 PM CST THU DEC 5 2013/
DISCUSSION...
THE COLD FRONT HAS PUSHED THROUGH ALL OF SOUTHEAST TEXAS THIS
AFTERNOON WITH A WIDE RANGE OF TEMPERATURES ACROSS THE REGION.
ALONG THE COAST TEMPERATURES REMAIN IN THE MID 60S IMMEDIATELY
BEHIND THE FRONT WHILE CALDWELL HAS FALLEN INTO THE UPPER 30S.
RESEARCH SOUNDING FROM COLLEGE STATION SHOWS A VERY SHALLOW COLD
LAYER WITH NOT MUCH MOISTURE ABOVE AT THE MOMENT...THIS ELEVATED
LAYER SHOULD BEGIN TO MOISTEN LATER TONIGHT AS A SHORTWAVE TROUGH
OVER NORTHERN MEXICO MAKES ITS APPROACH IN THE SOUTHWESTERLY FLOW
ALOFT. RAIN IS EXPECTED OVERNIGHT TONIGHT ACROSS MUCH OF THE
REGION ALTHOUGH TEMPERATURES LOOK TO REMAIN WARM ENOUGH ACROSS
SOUTHEAST TEXAS TO PRECLUDE ANY MIXED PRECIPITATION TONIGHT.
NEAR SURFACE TEMPERATURES DO BEGIN TO COOL FRIDAY AFTERNOON AND
EVENING ACROSS OUR NORTHERN COUNTIES BUT THIS WILL BE IN A RACE
WITH THE EXITING MOISTURE. THINK WE COULD SEE A MIX OF DRIZZLE AND
SOME FREEZING DRIZZLE ACROSS OUR FAR NORTHERN AND NORTHWESTERN
AREAS BUT QPF WILL BE LIGHT ENOUGH TO PRECLUDE ANY IMPACTS. TIME
OF GREATEST CONCERN FOR ANY ICE ACCUMULATION IN THE NEAR TERM
LOOKS TO BEGIN LATE SATURDAY AFTERNOON INTO SUNDAY MORNING AS THE
MODELS BRING MOISTURE BACK OVER THE REGION DUE TO A DEVELOPING
SURFACE LOW OVER THE SOUTH PLAINS. THIS FLOW COMBINED WITH THE
COLD NEAR SURFACE LAYER COULD PRODUCE A MIX OF RAIN AND FREEZING
RAIN ACROSS AREAS ALONG AND NORTH OF A LINE FROM NEAR COLUMBUS TO
SPRING TO LIVINGSTON. THE HOUSTON METRO AREA WILL LARGELY SEE
PRECIPITATION REMAIN AS RAIN BUT SOME ELEVATED ROADWAYS IN THE FAR
WESTERN AND NORTHERN SUBURBS COULD PICK UP A FEW SLICK SPOTS BY
SUNDAY MORNING. TEMPERATURES ON SUNDAY WILL WARM INTO THE UPPER
30S AND LOW 40S WHICH SHOULD ALLOW CONDITIONS TO IMPROVE BY MID
MORNING.
ANOTHER PUSH OF ARCTIC AIR IS EXPECTED TO ARRIVE ON MONDAY...WITH
TEMPERATURES REMAINING IN THE 30S AND 40S THROUGH WEDNESDAY. WILL
CARRY SLIGHT POPS THROUGH THIS PERIOD AS MODELS DISAGREE ON THE
POTENTIAL FOR RAINFALL. A SLOW WARMING TREND IS THEN EXPECTED
THROUGH THE END OF NEXT WEEK. 38/23
MARINE...
NORTH WINDS IN THE WAKE OF THE FRONT WILL BE 10-15 INCREASING TO
20-25 FRIDAY SO SCA FLAG IS UP AND SHOULD CONTINUE INTO SATURDAY
NIGHT. SEAS EVENTUALLY BUILDING TO 9-11 FEET WELL OFFSHORE. TIDE
LEVELS FALLING QUICKLY AND MAY HAVE A NEED FOR LOW WATER ADVISORY
FRIDAY AFTERNOON THROUGH SATURDAY.
45
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 56 33 35 27 34 / 20 60 70 10 40
HOUSTON (IAH) 75 38 39 33 38 / 30 40 70 20 50
GALVESTON (GLS) 75 46 48 37 45 / 20 40 70 20 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST FRIDAY FOR THE FOLLOWING
ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS FROM FREEPORT
TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS
FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...43
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
805 PM CST THU DEC 5 2013
.UPDATE...
SEE EVENING UPDATE.
&&
.DISCUSSION...
AT 01Z...A COLD FRONT EXTENDED FROM SOUTH CENTRAL LOUISIANA
ACROSS THE WESTERN GULF. A VERY TIGHT PRESSURE GRADIENT IS IN
PLACE AND WIND SPEEDS ARE APPROACHING ADVISORY CRITERIA. WILL
WATCH TRENDS BUT WILL HOLD OFF ON A WIND ADVISORY FOR THE COASTAL
COUNTIES FOR NOW. WATER TEMPS HAVE COOLED A BIT SINCE THE LAST
FROPA...SO FEEL THERMAL CONTRIBUTION TO WINDS WILL BE LESS THAN
PAST COUPLE OF EVENTS. RAP GUIDANCE ALSO SUGGESTS THAT WINDS WILL
REMAIN BELOW ADVISORY CRITERIA.
POPS ARE RATHER HIGH CONSIDERING THE RADAR LOOKS SO BENIGN AT THE
CURRENT TIME. 00Z 850 MB ANALYSIS SHOWS WINDS STILL OUT OF THE
SOUTH WITH AN 850 MB FRONT EXTENDING FROM TEXARKANA TO ABOUT
LAREDO. ISENTROPIC UPGLIDE HAS NOT REALLY KICKED IN YET AS NORTH
WINDS REMAIN VERY SHALLOW. THIS SHOULD CHANGE OVERNIGHT AS THE
850 MB FRONT CLEARS THE COAST. 00Z SOUNDINGS SHOW A SATURATED
LAYER FROM THE SURFACE TO 850 MB...AND VERY DRY AIR ABOVE THE
SATURATED LAYER. NAM12 AND RAP FORECAST SOUNDINGS CLOSELY MATCH
THE 00Z SOUNDINGS. THIS TYPE OF SOUNDING FAVORS DRIZZLE OVER RAIN.
EITHER WAY...EXPECT CONDS TO BECOME INCREASINGLY DAMP OVERNIGHT.
TEMP FCST LOOKS TO BE ON TRACK. NOT EXPECTING FREEZING TEMPS
OVERNIGHT BUT CALDWELL (RWV) IS GETTING CLOSE. CURRENT TEMP AT RWV
IS 34 DEGREES WITH A DEW PT OF 30. HAVE SOME CONCERN THAT DEW
POINTS NEAR 30 WILL ALLOW FOR SOME EVAPORATIVE COOLING ONCE PRECIP
BEGINS AND THEN INSTEAD OF DRIZZLE...WE GET FREEZING DRIZZLE.
WILL AGAIN WATCH TRENDS BUT FEEL CURRENT FCST HAS A GOOD HANDLE
ON TONIGHT`S TEMP/PRECIP TRENDS. HAVE MADE MINOR CHANGES TO THE
GRIDS. NEW ZFP OUT BY 900 PM. 43
&&
.PREV DISCUSSION... /ISSUED 523 PM CST THU DEC 5 2013/
DISCUSSION...
SEE THE 06Z AVIATION DISCUSSION BELOW.
40
AVIATION...
ISENTROPIC LIFT WILL HELP LOWER MVFR CONDITIONS TO IFR BY MID
EVENING. MODEL FORECAST SOUNDINGS AND THE NAM12 RAINFALL FORECAST
SHOW THAT RAIN IS MOST PROBABLE FRIDAY MORNING THROUGH THE MID
AFTERNOON PERIOD. WINDS WILL BE ANOTHER FACTOR...WITH GUSTY
CONDITIONS MOST LIKELY ALONG THE COAST THROUGH THE PERIOD...WHILE
MAINLY AFTER 13Z FRIDAY OVER THE INLAND SITES.
40
PREV DISCUSSION... /ISSUED 346 PM CST THU DEC 5 2013/
DISCUSSION...
THE COLD FRONT HAS PUSHED THROUGH ALL OF SOUTHEAST TEXAS THIS
AFTERNOON WITH A WIDE RANGE OF TEMPERATURES ACROSS THE REGION.
ALONG THE COAST TEMPERATURES REMAIN IN THE MID 60S IMMEDIATELY
BEHIND THE FRONT WHILE CALDWELL HAS FALLEN INTO THE UPPER 30S.
RESEARCH SOUNDING FROM COLLEGE STATION SHOWS A VERY SHALLOW COLD
LAYER WITH NOT MUCH MOISTURE ABOVE AT THE MOMENT...THIS ELEVATED
LAYER SHOULD BEGIN TO MOISTEN LATER TONIGHT AS A SHORTWAVE TROUGH
OVER NORTHERN MEXICO MAKES ITS APPROACH IN THE SOUTHWESTERLY FLOW
ALOFT. RAIN IS EXPECTED OVERNIGHT TONIGHT ACROSS MUCH OF THE
REGION ALTHOUGH TEMPERATURES LOOK TO REMAIN WARM ENOUGH ACROSS
SOUTHEAST TEXAS TO PRECLUDE ANY MIXED PRECIPITATION TONIGHT.
NEAR SURFACE TEMPERATURES DO BEGIN TO COOL FRIDAY AFTERNOON AND
EVENING ACROSS OUR NORTHERN COUNTIES BUT THIS WILL BE IN A RACE
WITH THE EXITING MOISTURE. THINK WE COULD SEE A MIX OF DRIZZLE AND
SOME FREEZING DRIZZLE ACROSS OUR FAR NORTHERN AND NORTHWESTERN
AREAS BUT QPF WILL BE LIGHT ENOUGH TO PRECLUDE ANY IMPACTS. TIME
OF GREATEST CONCERN FOR ANY ICE ACCUMULATION IN THE NEAR TERM
LOOKS TO BEGIN LATE SATURDAY AFTERNOON INTO SUNDAY MORNING AS THE
MODELS BRING MOISTURE BACK OVER THE REGION DUE TO A DEVELOPING
SURFACE LOW OVER THE SOUTH PLAINS. THIS FLOW COMBINED WITH THE
COLD NEAR SURFACE LAYER COULD PRODUCE A MIX OF RAIN AND FREEZING
RAIN ACROSS AREAS ALONG AND NORTH OF A LINE FROM NEAR COLUMBUS TO
SPRING TO LIVINGSTON. THE HOUSTON METRO AREA WILL LARGELY SEE
PRECIPITATION REMAIN AS RAIN BUT SOME ELEVATED ROADWAYS IN THE FAR
WESTERN AND NORTHERN SUBURBS COULD PICK UP A FEW SLICK SPOTS BY
SUNDAY MORNING. TEMPERATURES ON SUNDAY WILL WARM INTO THE UPPER
30S AND LOW 40S WHICH SHOULD ALLOW CONDITIONS TO IMPROVE BY MID
MORNING.
ANOTHER PUSH OF ARCTIC AIR IS EXPECTED TO ARRIVE ON MONDAY...WITH
TEMPERATURES REMAINING IN THE 30S AND 40S THROUGH WEDNESDAY. WILL
CARRY SLIGHT POPS THROUGH THIS PERIOD AS MODELS DISAGREE ON THE
POTENTIAL FOR RAINFALL. A SLOW WARMING TREND IS THEN EXPECTED
THROUGH THE END OF NEXT WEEK. 38/23
MARINE...
NORTH WINDS IN THE WAKE OF THE FRONT WILL BE 10-15 INCREASING TO
20-25 FRIDAY SO SCA FLAG IS UP AND SHOULD CONTINUE INTO SATURDAY
NIGHT. SEAS EVENTUALLY BUILDING TO 9-11 FEET WELL OFFSHORE. TIDE
LEVELS FALLING QUICKLY AND MAY HAVE A NEED FOR LOW WATER ADVISORY
FRIDAY AFTERNOON THROUGH SATURDAY.
45
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 33 35 27 34 31 / 60 70 10 40 40
HOUSTON (IAH) 38 39 33 38 33 / 40 70 20 50 50
GALVESTON (GLS) 46 48 37 45 40 / 40 70 20 50 40
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST FRIDAY FOR THE FOLLOWING
ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS FROM FREEPORT
TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS
FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...43
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
552 PM CST THU DEC 5 2013
.DISCUSSION...SEE AVIATION DISCUSSION BELOW FOR THE 00Z TAFS.
&&
.AVIATION...LOW END MVFR CIGS WILL PERSIST THROUGH THE TAF PERIOD
ACROSS MUCH OF S TX IN THE WAKE OF A STRONG ARCTIC COLD FRONT THAT
MOVED THROUGH THE AREA EARLIER TODAY. LIGHT RAIN IS EXPECTED TO
DVLP OVERNIGHT AND BE INTERMITTENT THROUGH FRIDAY. VSBYS SHOULD
REMAIN AT VFR LEVELS BUT COULD LOWER BRIEFLY AT TIMES DUE TO THE
RAIN. MAIN AVIATION CONCERN WILL BE BY LATE FRIDAY AFTERNOON
ACROSS THE VCT TAF SITE DUE TO A SHALLOW LAYER OF MOISTURE FROM
APPROX. 1000-2000 FT THAT MAY BE BELOW FREEZING. THIS LAYER MAY
DEEPEN TO AT OR NEAR THE SFC LATE FRIDAY NIGHT ACROSS VCT. A
SHALLOW MOIST LAYER BELOW FREEZING BTWEEN 1100-2000FT COULD ALSO
OCCUR ACROSS LRD/ALI/CRP TAF SITES AS WELL BY EARLY SAT MORNING. A
WARM LAYER ABV FREEZING IS EXPECTED ABV 2000FT AND EXTENDING TO
AROUND 13000FT.
&&
.PREV DISCUSSION... /ISSUED 404 PM CST THU DEC 5 2013/
SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...AS OF WRITING...COLD
FRONT HAS CLEARED ALL BUT SOUTHERN WEBB COUNTY AND OFFSHORE
MARINE ZONES. MAIN FORECAST CHALLENGES FOR SHORT TERM PERIOD ARE
LIGHT PRECIP AND TEMPS. SHALLOW AND DRY AIRMASS FROM SFC TO H9 IS
CURRENTLY MOVING SOUTH INTO THE AREA WHICH SHOULD LIMIT PRECIP
POTENTIAL FOR THIS AFTERNOON AND EVENING. BY LATE EVENING /AND
ESPECIALLY AFTER MIDNIGHT/ WAA OVER SHALLOW COOL AIRMASS SHOULD
INCREASE RESULTING IN LIGHT DRIZZLE/RAIN DEVELOPING...WITH THE
PRECIP FORECAST REFLECTING A BLEND OF THE HRRR AND TTU 4KM WRF
/GIVEN BETTER MODEL RESOLUTION AND BETTER HANDLING OF SHALLOW
AIRMASS/ THE LIGHT PRECIP SHOULD SHIFT EAST LATE TONIGHT AND
THROUGH FRIDAY MORNING AS H5 S/W DISTURBANCE KICKS EAST AND H85
FRONT DRIFTS INTO THE CWA...WITH THE AFTERNOON AND EVENING HOURS
OF FRIDAY CURRENTLY FORECAST TO REMAIN DRY. UNCERTAINTY EXISTS AS
TO HOW MUCH DRY AIR WILL WORK INTO THE REGION FRIDAY AFTERNOON.
NAM IS THE DRIEST AND EVEN WANTS TO DEVELOP SOME SIGNIFICANT
BREAKS IN THE CLOUD COVER ACROSS THE BRUSH COUNTRY /WITH THE 12Z
ECMWF HINTING AT SOME SUNSHINE AS WELL/. GFS AND CMC ARE MORE
PESSIMISTIC AND KEEP THE CLOUD COVER THROUGH THE DAY. FOR
NOW...WILL GO WITH A BLEND AND INDICATE POSSIBILITY OF AT LEAST A
FEW PEAKS OF SUNSHINE...PRIMARILY ACROSS WESTERN ZONES. WEAK
COASTAL TROUGHING TRIES TO DEVELOP BY LATE FRIDAY NIGHT WHICH
COULD LEAD TO SOME LIGHT PRECIP ACROSS EASTERN HALF OF CWA. TEMPS
FRI NIGHT COULD APPROACH FREEZING ACROSS N/NE ZONES WHICH WOULD
POTENTIALLY ALLOW FOR SOME LIGHT FREEZING DRIZZLE ON ELEVATED
SURFACES. AT THIS TIME...ANY FREEZING DRIZZLE IS EXPECTED TO BE
BRIEF AND ISOLATED IN NATURE. WILL CONTINUE TO MONITOR SITUATION.
TEMPS TONIGHT ARE TRICKY AS EVAPORATIVE COOLING IN LOWEST 100 MB
COULD ALLOW TEMPS TO FALL INTO THE 30S AREAWIDE. FEEL THAT
GREATEST EVAP COOLING WILL BE ACROSS NE ZONES AND THUS HAVE
COOLEST TEMPS DRAWN THERE. HIGHS FRIDAY WILL BE ROUGHLY 25 DEGREES
BELOW NORMAL FOR THIS TIME OF YEAR...BUT COULD POTENTIALLY BE A
LITTLE WARMER THAN FORECAST VALUES IF ANY AFTERNOON SUNSHINE
DEVELOPS. SATURDAY NIGHT LOOKS TO BE COLDER THAN TONIGHT AS
STRONGER CAA OCCURS WITH ALMOST ALL LOCATIONS FALLING INTO AT
LEAST THE MID 30S. WITH CAA ADVECTION OCCURRING FRIDAY
NIGHT...SOME LOCATIONS /ESPECIALLY COASTAL PLAINS AND VICTORIA
REGION/ MAY HAVE WIND CHILL VALUES REACH WIND CHILL ADVISORY
CRITERIA /WIND CHILL VALUES OF 15 TO 25 DEGREES WITH SUSTAINED
WINDS OF AT LEAST 10 MPH/. WILL BE SOMETHING TO TAKE A LOOK WITH
FRIDAY/S FORECAST PACKAGES.
LONG TERM (SATURDAY THROUGH THURSDAY)...AS A SHORT WAVE TROUGH
MOVES FROM NORTHERN MEXICO SATURDAY AND THROUGH THE OZARKS BY
SUNDAY MORNING...WARM AIR ADVECTION IN THE 925-85H LAYER ALONG WITH
INCREASING ISENTROPIC LIFT WILL PROVIDE A CHANCE OF LIGHT RAIN OVER
THE AREA SATURDAY AND ESPECIALLY SATURDAY NIGHT AS SOUTHERLY FLOW AT
85H INCREASES TO 35-45 KNOTS. AT THE BEGINNING OF SATURDAY...SHALLOW
COLD AIR MASS MAY BE COLD ENOUGH TO PROVIDE A SMALL WINDOW FOR
FREEZING RAIN OR FREEZING DRIZZLE TO OCCUR FROM TILDEN OVER TO
BEEVILLE AND VICTORIA. WITH EXPECTED CLOUD COVER AND LIGHT RAIN
TEMPERATURES WILL NOT MOVE MUCH SATURDAY INTO SATURDAY NIGHT.
THE LOW LEVEL WARM AIR ADVECTION ZONE SHIFTS TO THE EAST ON THE
DAY SUNDAY WITH A POSSIBLE DECREASE IN CLOUD COVER OUT WEST FOR
A SLIGHT WARM UP. BUT THE NEXT STRONG UPPER LOW DIVING INTO THE
PACIFIC NORTHWEST DOWNSTREAM FROM AN IMPRESSIVE RIDGE INTO ALASKA
WILL LEAD TO ANOTHER DISPERSAL OF ARCTIC AIR THAT WILL REACH THE
REGION ON MONDAY. MOISTURE WILL BE SHUNTED TO THE EAST AND A VERY
STRONG OFFSHORE FLOW WILL OCCUR MONDAY NIGHT INTO TUESDAY MORNING.
HIGH PRESSURE SETTLING INTO THE REGION SHOULD LEAD TO FREEZING
TEMPERATURES ACROSS MUCH OF SOUTH TEXAS BY TUESDAY MORNING. THERE
ARE SOME DIFFERENCES IN HOW THE MEDIUM RANGE MODELS HANDLE ENERGY
IN THE SOUTHERN STREAM LATE IN THE PERIOD. ECMWF SHOWS A STRONGER
SHORT WAVE TROUGH MOVING OUT OF MEXICO INTO TEXAS WEDNESDAY AND
THURSDAY THAT WOULD LEAD TO SOME MOISTURE OVERRUNNING THE COLD AIR
AT THE SURFACE AND POSSIBLY INCREASED RAIN CHANCES. BUT FOR NOW WENT
WITH THE OTHER MODELS AND KEPT THE FORECAST DRY FOR WEDNESDAY AND
THURSDAY. SHOWED ONLY A MODEST WARM UP TO THE MID/UPPER 50S BY
THURSDAY.
MARINE...WIND SPEEDS SHOULD INCREASE THROUGH THE REMAINDER OF THE
AFTERNOON AND EARLY EVENING AS COLD FRONT PUSHES THROUGH. WINDS
MAY ACTUALLY DECREASE IN INTENSITY OVERNIGHT BEFORE BECOMING A
STRONG OFFSHORE FLOW FRIDAY AND THROUGH THE WEEKEND. WAVE HEIGHTS
WILL BUILD SIGNIFICANTLY FRIDAY WITH ADDITIONAL SMALL CRAFT
ADVISORIES LIKELY FRIDAY AND OVER THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 41 44 35 38 35 / 50 60 20 40 50
VICTORIA 36 41 32 36 33 / 60 70 20 50 50
LAREDO 44 51 35 40 36 / 50 30 10 20 20
ALICE 40 44 34 37 34 / 50 50 20 40 40
ROCKPORT 41 45 33 38 37 / 60 70 20 50 50
COTULLA 41 48 32 38 33 / 60 40 10 20 20
KINGSVILLE 41 46 34 38 35 / 50 60 20 40 40
NAVY CORPUS 43 46 35 39 38 / 50 60 20 50 50
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT
ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT
O`CONNOR...COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS
OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA
SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT
ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
&&
$$
TE/81...AVIATION
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1201 PM CST WED DEC 4 2013
.AVIATION...
COMPLEX AVIATION FORECAST CONTINUES AS PERIPHERY OF ARCTIC AIRMASS
HAS SHIFTED SOUTH OF THE TERMINALS. LOW CLOUDS/STRATUS ARE
LAGGING...BUT HAVE SETTLED IN AT KGUY AND EDGED VERY NEAR KDHT.
TIMING FLIGHT CATEGORIES WITH THE INVADING STRATUS WILL BE DIFFICULT
DURING THE NEXT 6-12 HOURS. PROBABILITIES FOR RESTRICTIONS DUE TO
PRECIPITATION WILL INCREASE DURING THE 04/06-12Z TIMEFRAME.
&&
.PREV DISCUSSION... /ISSUED 1146 AM CST WED DEC 4 2013/
UPDATE...
UPDATE TO REWORK THE WINTER WEATHER ADVISORY. WILL NOW START THE
ADVISORY AT MIDNIGHT TONIGHT AND CONTINUE THROUGH 9 AM FRIDAY. THOUGH
WE ARE NOT EXPECTED SNOW TO LAST THROUGH THIS ENTIRE TIME...WE ALSO
WANTED TO EMPHASIZE THE DANGEROUS WIND CHILL VALUES.
JOHNSON
PREV DISCUSSION... /ISSUED 534 AM CST WED DEC 4 2013/
DISCUSSION...
THE ANTICIPATED COLD FRONT IS CURRENTLY WORKING SOUTH THROUGH THE
FORECAST AREA...WITH AN EXPECTED SURGE OF ARCTIC AIR LATER TODAY
PLUNGING THE PANHANDLES INTO SUBFREEZING TEMPERATURES THROUGH AT
LEAST THE WEEKEND. A PERIOD OF SNOWFALL WILL BE POSSIBLE FROM LATE
TONIGHT THROUGH EARLY FRIDAY MORNING. FURTHER CHANCES FOR LIGHT SNOW
MAY RETURN LATE IN THE WEEKEND.
SHORT TERM...TODAY THROUGH FRIDAY MORNING...
EVEN AT THIS LATE HOUR...THERE CONTINUES TO BE MODEL DISAGREEMENT
OVER THE TIMING AND POSITION OF THE COLD FRONT TODAY. AT LEAST AN
INITIAL SURGE HAS PUSHED THE FRONT TO THE SOUTH OF OUR CWA THIS
MORNING. THE LATEST RAP CONTINUES TO INDICATE A SLIGHT RETREAT OF THE
FRONT THIS AFTERNOON...ALLOWING FOR THE FAR SOUTHWEST TX PANHANDLE TO
WARM INTO THE UPPER 50S OR LOWER 60S. A FINAL SURGE OF COLD AIR
SHOULD PUSH THE FRONT SOUTH OF OUR AREA BY SUNSET TONIGHT. THEN...THE
ARCTIC AIR IS HERE TO STAY. NIGHTTIME LOWS IN THE LOW SINGLE DIGITS
TO MID TEENS...AND DAYTIME HIGHS IN THE TEENS TO 20S WILL BE POSSIBLE
FOLLOWING THE COLD FRONT.
LIGHT SNOW WILL BE POSSIBLE BEFORE MIDNIGHT TONIGHT IN THE WESTERN OK
PANHANDLE AND FAR NW TX PANHANDLE. ACCUMULATIONS OF SNOW SHOULD BE
MINIMAL FROM THIS FIRST ROUND. BY NOON THURSDAY...A MUCH MORE
PRONOUNCED FRONTOGENETIC BAND OF SNOW SHOULD SET UP ROUGHLY FROM
HARTLEY COUNTY TO TEXAS COUNTY. ALL GUIDANCE IS IN FAIRLY GOOD
AGREEMENT ON THE PLACEMENT OF THIS BAND THROUGH TOMORROW AFTERNOON. A
POSSIBLE SECOND BAND SOUTHWARD SHIFT OF THE FIRST COULD BRING
INCREASED SNOW ACCUMULATIONS ALONG A LINE FROM VEGA TO BEAVER HEADING
INTO THE EVENING.
CURRENT THINKING HAS MOST SNOWFALL CLEARING FROM NORTHWEST TO
SOUTHEAST OVERNIGHT THURSDAY INTO FRIDAY...WITH THE LAST ACCUMULATING
SNOW FALLING IN THE SOUTHEAST TEXAS PANHANDLE BETWEEN MIDNIGHT FRIDAY
TO 6 AM THAT MORNING. SOME PERIODS OF FLURRIES COULD LINGER BEHIND
UNTIL DRIER MID LEVEL AIR FINALLY BUILDS OVER THE PANHANDLES.
OVERALL...WE ARE EXPECTING AVERAGE AMOUNTS OF 1 TO 3 INCHES OF SNOW
ACROSS THE PANHANDLES FROM TONIGHT THROUGH FRIDAY MORNING...WITH
LOCALLY HIGHER AMOUNTS UP TO 5 INCHES POSSIBLE UNDER HEAVIER SNOW
BANDS. A WINTER WEATHER ADVISORY WILL BE ISSUED TO ADDRESS THIS
SNOWFALL POTENTIAL.
NF
LONG TERM...FRIDAY THROUGH TUESDAY...
AS THE MAIN SHOT AT SNOW CLEARS THE AREA...THE MAIN STORY THROUGH THE
WEEKEND WILL BE THE PERSISTENT COLDER AIR IN PLACE THROUGH EARLY NEXT
WEEK. THINK NIGHTTIME LOWS IN THE LOW SINGLE DIGITS TO MID TEENS
WILL BE POSSIBLE MOST NIGHTS THROUGH THE MIDDLE OF NEXT WEEK...WITH
DAYTIME HIGHS IN THE TEENS AND TWENTIES THROUGH SATURDAY.
SOUTHWESTERLY WINDS ON SUNDAY MAY HELP TO BRING TEMPERATURES UP TO
NEAR FREEZING...THOUGH THINK CLOUD COVER WILL KEEP MOST PLACES BELOW
FREEZING EVEN ON SUNDAY AND MONDAY. CURRENTLY THINK TUESDAY WILL BE
FIRST CHANCE TO CLIMB ABOVE THE FREEZING MARK. DANGEROUSLY COLD WIND
CHILLS BETWEEN ZERO AND 15 BELOW ZERO WILL BE POSSIBLE DURING THIS
TIME AS WELL.
CANNOT RULE OUT A SLIGHT CHANCE FOR LIGHT SNOW SATURDAY NIGHT INTO
SUNDAY...THOUGH AT THIS TIME THINK ANY ACCUMULATIONS WOULD BE LESS
THAN ONE HALF INCH.
NF
FIRE WEATHER...
ONLY A BRIEF PERIOD OF ELEVATED FIRE WEATHER CONDITIONS WILL BE
POSSIBLE THIS AFTERNOON IN THE FAR SOUTHWEST TEXAS PANHANDLE...SHOULD
THE COLD FRONT IN FACT RETREAT NORTHEAST DURING THE DAY.
OTHERWISE...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED THROUGH THE MIDDLE OF NEXT WEEK.
NF
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST FRIDAY
FOR THE FOLLOWING ZONES: ARMSTRONG...CARSON...
COLLINGSWORTH...DALLAM...DEAF SMITH...DONLEY...GRAY...
HANSFORD...HARTLEY...HEMPHILL...HUTCHINSON...LIPSCOMB...
MOORE...OCHILTREE...OLDHAM...POTTER...RANDALL...ROBERTS...
SHERMAN...WHEELER.
OK...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST FRIDAY
FOR THE FOLLOWING ZONES: BEAVER...CIMARRON...TEXAS.
&&
$$
10/16
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1146 AM CST WED DEC 4 2013
.UPDATE...
UPDATE TO REWORK THE WINTER WEATHER ADVISORY. WILL NOW START THE
ADVISORY AT MIDNIGHT TONIGHT AND CONTINUE THROUGH 9 AM FRIDAY. THOUGH
WE ARE NOT EXPECTED SNOW TO LAST THROUGH THIS ENTIRE TIME...WE ALSO
WANTED TO EMPHASIZE THE DANGEROUS WIND CHILL VALUES.
JOHNSON
&&
.PREV DISCUSSION... /ISSUED 1038 AM CST WED DEC 4 2013/
UPDATE...
UPDATE TO LOWER TEMPERATURES FOR TODAY. EVEN WITH A SURFACE LOW
DEVELOPING...DO NOT EXPECT THE FRONT TO MAKE MUCH PROGRESS NORTH
GIVEN HOW DENSE THE AIR MASS IS. THUS...THINK ONLY THE EXTREME SW TX
PANHANDLE HAS A CHANCE TO WARM UP SIGNIFICANTLY TODAY.
JOHNSON
PREV DISCUSSION... /ISSUED 556 AM CST WED DEC 4 2013/
AVIATION...
FOR THE 12Z TAFS, THIS IS A LOW CONFIDENCE FORECAST.
A COLD FRONT HAS PASSED THROUGH ALL THE TERMINALS WITH N/NE WINDS
LIKELY TO CONTINUE THROUGH THE REMAINDER OF THIS TAF PERIOD. A
SECONDARY COLD FRONT WILL ARRIVE 00Z-03Z WITH NE WINDS GUSTING UP TO
25 KT.
THE MOST PROBLEMATIC ASPECT OF THIS FORECAST IS FLIGHT CATEGORIES,
AND FORECAST CONFIDENCE IS VERY LOW.
LLWS ASSOCIATED WITH THE COLD FRONT WILL CONTINUE AT KAMA AND KDHT
THROUGH 16Z WHEN WINDS WEAKEN ALOFT. DESPITE THE WEAKENING WINDS
ALOFT, THERE WILL STILL BE AT LEAST A 150 DEGREE WIND SHIFT WITHIN
THE LOWEST 2000 FT THROUGHOUT THIS TAF PERIOD.
-SN WILL BE POSSIBLE AT KDHT AND KGUY AFTER 09Z, BUT DRY AIR NEAR
THE SURFACE MAY ALLOW THIS TO HOLD OFF UNTIL AFTER THIS TAF PERIOD.
JACKSON
PREV DISCUSSION... /ISSUED 534 AM CST WED DEC 4 2013/
DISCUSSION...
THE ANTICIPATED COLD FRONT IS CURRENTLY WORKING SOUTH THROUGH THE
FORECAST AREA...WITH AN EXPECTED SURGE OF ARCTIC AIR LATER TODAY
PLUNGING THE PANHANDLES INTO SUBFREEZING TEMPERATURES THROUGH AT
LEAST THE WEEKEND. A PERIOD OF SNOWFALL WILL BE POSSIBLE FROM LATE
TONIGHT THROUGH EARLY FRIDAY MORNING. FURTHER CHANCES FOR LIGHT SNOW
MAY RETURN LATE IN THE WEEKEND.
SHORT TERM...TODAY THROUGH FRIDAY MORNING...
EVEN AT THIS LATE HOUR...THERE CONTINUES TO BE MODEL DISAGREEMENT
OVER THE TIMING AND POSITION OF THE COLD FRONT TODAY. AT LEAST AN
INITIAL SURGE HAS PUSHED THE FRONT TO THE SOUTH OF OUR CWA THIS
MORNING. THE LATEST RAP CONTINUES TO INDICATE A SLIGHT RETREAT OF THE
FRONT THIS AFTERNOON...ALLOWING FOR THE FAR SOUTHWEST TX PANHANDLE TO
WARM INTO THE UPPER 50S OR LOWER 60S. A FINAL SURGE OF COLD AIR
SHOULD PUSH THE FRONT SOUTH OF OUR AREA BY SUNSET TONIGHT. THEN...THE
ARCTIC AIR IS HERE TO STAY. NIGHTTIME LOWS IN THE LOW SINGLE DIGITS
TO MID TEENS...AND DAYTIME HIGHS IN THE TEENS TO 20S WILL BE POSSIBLE
FOLLOWING THE COLD FRONT.
LIGHT SNOW WILL BE POSSIBLE BEFORE MIDNIGHT TONIGHT IN THE WESTERN OK
PANHANDLE AND FAR NW TX PANHANDLE. ACCUMULATIONS OF SNOW SHOULD BE
MINIMAL FROM THIS FIRST ROUND. BY NOON THURSDAY...A MUCH MORE
PRONOUNCED FRONTOGENETIC BAND OF SNOW SHOULD SET UP ROUGHLY FROM
HARTLEY COUNTY TO TEXAS COUNTY. ALL GUIDANCE IS IN FAIRLY GOOD
AGREEMENT ON THE PLACEMENT OF THIS BAND THROUGH TOMORROW AFTERNOON. A
POSSIBLE SECOND BAND SOUTHWARD SHIFT OF THE FIRST COULD BRING
INCREASED SNOW ACCUMULATIONS ALONG A LINE FROM VEGA TO BEAVER HEADING
INTO THE EVENING.
CURRENT THINKING HAS MOST SNOWFALL CLEARING FROM NORTHWEST TO
SOUTHEAST OVERNIGHT THURSDAY INTO FRIDAY...WITH THE LAST ACCUMULATING
SNOW FALLING IN THE SOUTHEAST TEXAS PANHANDLE BETWEEN MIDNIGHT FRIDAY
TO 6 AM THAT MORNING. SOME PERIODS OF FLURRIES COULD LINGER BEHIND
UNTIL DRIER MID LEVEL AIR FINALLY BUILDS OVER THE PANHANDLES.
OVERALL...WE ARE EXPECTING AVERAGE AMOUNTS OF 1 TO 3 INCHES OF SNOW
ACROSS THE PANHANDLES FROM TONIGHT THROUGH FRIDAY MORNING...WITH
LOCALLY HIGHER AMOUNTS UP TO 5 INCHES POSSIBLE UNDER HEAVIER SNOW
BANDS. A WINTER WEATHER ADVISORY WILL BE ISSUED TO ADDRESS THIS
SNOWFALL POTENTIAL.
NF
LONG TERM...FRIDAY THROUGH TUESDAY...
AS THE MAIN SHOT AT SNOW CLEARS THE AREA...THE MAIN STORY THROUGH THE
WEEKEND WILL BE THE PERSISTENT COLDER AIR IN PLACE THROUGH EARLY NEXT
WEEK. THINK NIGHTTIME LOWS IN THE LOW SINGLE DIGITS TO MID TEENS
WILL BE POSSIBLE MOST NIGHTS THROUGH THE MIDDLE OF NEXT WEEK...WITH
DAYTIME HIGHS IN THE TEENS AND TWENTIES THROUGH SATURDAY.
SOUTHWESTERLY WINDS ON SUNDAY MAY HELP TO BRING TEMPERATURES UP TO
NEAR FREEZING...THOUGH THINK CLOUD COVER WILL KEEP MOST PLACES BELOW
FREEZING EVEN ON SUNDAY AND MONDAY. CURRENTLY THINK TUESDAY WILL BE
FIRST CHANCE TO CLIMB ABOVE THE FREEZING MARK. DANGEROUSLY COLD WIND
CHILLS BETWEEN ZERO AND 15 BELOW ZERO WILL BE POSSIBLE DURING THIS
TIME AS WELL.
CANNOT RULE OUT A SLIGHT CHANCE FOR LIGHT SNOW SATURDAY NIGHT INTO
SUNDAY...THOUGH AT THIS TIME THINK ANY ACCUMULATIONS WOULD BE LESS
THAN ONE HALF INCH.
NF
FIRE WEATHER...
ONLY A BRIEF PERIOD OF ELEVATED FIRE WEATHER CONDITIONS WILL BE
POSSIBLE THIS AFTERNOON IN THE FAR SOUTHWEST TEXAS PANHANDLE...SHOULD
THE COLD FRONT IN FACT RETREAT NORTHEAST DURING THE DAY.
OTHERWISE...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED THROUGH THE MIDDLE OF NEXT WEEK.
NF
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST FRIDAY
FOR THE FOLLOWING ZONES: ARMSTRONG...CARSON...
COLLINGSWORTH...DALLAM...DEAF SMITH...DONLEY...GRAY...
HANSFORD...HARTLEY...HEMPHILL...HUTCHINSON...LIPSCOMB...
MOORE...OCHILTREE...OLDHAM...POTTER...RANDALL...ROBERTS...
SHERMAN...WHEELER.
OK...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST FRIDAY
FOR THE FOLLOWING ZONES: BEAVER...CIMARRON...TEXAS.
&&
$$
10/16
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1135 AM CST WED DEC 4 2013
.DISCUSSION...
See 18Z aviation discussion below.
&&
.AVIATION...
Expect VFR condition to persist through the evening hours. As the
arctic front moves through 09Z tomorrow morning expect MVFR cigs
to develop. IFR cigs will likely develop later in the day, but
will leave that for the 00Z TAF package. This afternoon the
southern terminals could see some southwest wind gusts but are not
expected to last long enough to include in the TAF package.
&&
.PREV DISCUSSION... /ISSUED 841 AM CST Wed Dec 4 2013/
UPDATE...
Updated temperatures and winds across the northern Big Country.
DISCUSSION...
Initial cold front has dropped into the northern Big Country
counties of Haskell and Throckmorton. Latest RUC and NAM data
suggests that the temperatures behind the front will still climb
today, but just not as fast. Have lowered afternoon highs and
adjusted temperatures and winds for the rest of the day.
Models suggest the front will approach Abilene this afternoon and
then stall. Will not bring it in at this point, but will continue to
monitor.
PREV DISCUSSION... /ISSUED 558 AM CST WED DEC 4 2013/
AVIATION...
/12Z TAFS/
Expect VFR conditions at the terminals during the next 24 hours as
high clouds stream northeast across West Central Texas. The winds
will be southwest to west with gusts to near 20 knots this
afternoon. Also, a cold front will move to just south of the I-20
corridor by late tonight, and have shifted the wind to the north at
the KABI terminal after 06Z Thursday.
21
PREV DISCUSSION... /ISSUED 510 AM CST WED DEC 4 2013/
SHORT TERM...
Today
Look for one more day of unseasonably warm afternoon highs.
Temperatures at 850 mb increase again this afternoon across West
Central Texas. Although cloud cover will be increasing today, gusty
west, down-slope, winds will help push afternoon highs into the mid
to upper 70s across the Big Country and into the 80 to 85 range
elsewhere.
Huber
Tonight
Another strong cold front will move into the Big country around
midnight tonight. The NAM continues to be faster than the GFS. Our
wind grids reflect a timing closer to the faster NAM; thus, I expect
north surface winds to dominate the Big Country north of Interstate
20 by midnight tonight. Thus, lows there tonight will be mainly in
the 30 to 35 range. Elsewhere, 40s look good.
Huber
Thursday through Friday night
Unseasonably cold temperatures and a wintry precipitation mix will
dominate the remainder of the short term. Well, we`ve closely
watched the models develop this next arctic system for the last
several days, and we`re becoming more confident with accumulations
of sleet or freezing rain which may exceed our one quarter inch
warning threshold, mainly across the Big Country. I did note model
forecast sounding are indicating much deeper saturation in the
column, as compared to this time last night. So, with greater
confidence for significant accumulation, we have a Winter Storm
Watch in effect for all our Big Country counties. The latest
Weather Prediction Center guidance indicates possible
accumulations across mainly our Big Country counties of at least
one quarter inch. Elsewhere across West Central Texas, my
confidence is not as high for any accumulations close to one
quarter inch. Thus, we will continue a Special Weather Statement
for our remaining counties. The best chance for precipitation will
be Thursday night, as an upper trough moves over the region. As if
the ice and sleet accumulations weren`t enough, I`m also concerned
about temperatures Thursday night and corresponding wind chill,
especially across the Big Country. With lows in the teens there,
gusty north winds will create very dangerous wind chill numbers
around zero degrees. On Friday, strong cold air advection
continues, with surface winds from the north around 15 mph. The
wintry precipitation mix will continue until around noon; then,
the upper trough axis moves east of our area. Overnight Friday
night, very dangerous wind chill numbers will again dominate the
Big Country and even parts of the Concho valley and Heartland.
With north surface winds continuing Friday night, cold air
advection will create colder lows than Thursday night.
Huber
LONG TERM...
Saturday through Sunday
Unseasonably cold temperatures will continue through the weekend. As
a very dominate arctic airmass settles over Texas for the weekend,
unseasonably cold temperatures will continue. Highs Saturday will
likely remain at or just below freezing for most of West Central
Texas. Thus, any remaining ice will likely be slow to melt, if it
melts at all. Another short wave aloft will move across the southern
plains on Saturday and perhaps bring another brief round of wintry
precipitation to West central Texas. My confidence isn`t very high
regarding the potential for additional precipitation with this
secondary short wave; thus, I`ve continued only slight chance PoPs
for the Saturday period. As for temperatures, Sunday doesn`t look
much better. Returning sunshine Sunday will help lift temperatures
above the freezing mark for the afternoon hours. Nevertheless, highs
in the lower 30s for much of the Big Country on Sunday aren`t what
I`d call warm!
Huber
Sunday night through Tuesday
For the start of next week, temperatures do begin to rebound just
slightly; but, they remain well below seasonal normals.
Huber
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 27 31 20 25 15 / 30 60 70 30 10
San Angelo 41 42 24 31 20 / 20 50 70 20 10
Junction 48 52 26 33 24 / 20 40 70 30 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH from Thursday afternoon through Friday
morning FOR THE FOLLOWING ZONES: Callahan...Fisher...Haskell...
Jones...Nolan...Shackelford...Taylor...Throckmorton.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1038 AM CST WED DEC 4 2013
.UPDATE...
UPDATE TO LOWER TEMPERATURES FOR TODAY. EVEN WITH A SURFACE LOW
DEVELOPING...DO NOT EXPECT THE FRONT TO MAKE MUCH PROGRESS NORTH
GIVEN HOW DENSE THE AIR MASS IS. THUS...THINK ONLY THE EXTREME SW TX
PANHANDLE HAS A CHANCE TO WARM UP SIGNIFICANTLY TODAY.
JOHNSON
&&
.PREV DISCUSSION... /ISSUED 556 AM CST WED DEC 4 2013/
AVIATION...
FOR THE 12Z TAFS, THIS IS A LOW CONFIDENCE FORECAST.
A COLD FRONT HAS PASSED THROUGH ALL THE TERMINALS WITH N/NE WINDS
LIKELY TO CONTINUE THROUGH THE REMAINDER OF THIS TAF PERIOD. A
SECONDARY COLD FRONT WILL ARRIVE 00Z-03Z WITH NE WINDS GUSTING UP TO
25 KT.
THE MOST PROBLEMATIC ASPECT OF THIS FORECAST IS FLIGHT CATEGORIES,
AND FORECAST CONFIDENCE IS VERY LOW.
LLWS ASSOCIATED WITH THE COLD FRONT WILL CONTINUE AT KAMA AND KDHT
THROUGH 16Z WHEN WINDS WEAKEN ALOFT. DESPITE THE WEAKENING WINDS
ALOFT, THERE WILL STILL BE AT LEAST A 150 DEGREE WIND SHIFT WITHIN
THE LOWEST 2000 FT THROUGHOUT THIS TAF PERIOD.
-SN WILL BE POSSIBLE AT KDHT AND KGUY AFTER 09Z, BUT DRY AIR NEAR
THE SURFACE MAY ALLOW THIS TO HOLD OFF UNTIL AFTER THIS TAF PERIOD.
JACKSON
PREV DISCUSSION... /ISSUED 534 AM CST WED DEC 4 2013/
DISCUSSION...
THE ANTICIPATED COLD FRONT IS CURRENTLY WORKING SOUTH THROUGH THE
FORECAST AREA...WITH AN EXPECTED SURGE OF ARCTIC AIR LATER TODAY
PLUNGING THE PANHANDLES INTO SUBFREEZING TEMPERATURES THROUGH AT
LEAST THE WEEKEND. A PERIOD OF SNOWFALL WILL BE POSSIBLE FROM LATE
TONIGHT THROUGH EARLY FRIDAY MORNING. FURTHER CHANCES FOR LIGHT SNOW
MAY RETURN LATE IN THE WEEKEND.
SHORT TERM...TODAY THROUGH FRIDAY MORNING...
EVEN AT THIS LATE HOUR...THERE CONTINUES TO BE MODEL DISAGREEMENT
OVER THE TIMING AND POSITION OF THE COLD FRONT TODAY. AT LEAST AN
INITIAL SURGE HAS PUSHED THE FRONT TO THE SOUTH OF OUR CWA THIS
MORNING. THE LATEST RAP CONTINUES TO INDICATE A SLIGHT RETREAT OF THE
FRONT THIS AFTERNOON...ALLOWING FOR THE FAR SOUTHWEST TX PANHANDLE TO
WARM INTO THE UPPER 50S OR LOWER 60S. A FINAL SURGE OF COLD AIR
SHOULD PUSH THE FRONT SOUTH OF OUR AREA BY SUNSET TONIGHT. THEN...THE
ARCTIC AIR IS HERE TO STAY. NIGHTTIME LOWS IN THE LOW SINGLE DIGITS
TO MID TEENS...AND DAYTIME HIGHS IN THE TEENS TO 20S WILL BE POSSIBLE
FOLLOWING THE COLD FRONT.
LIGHT SNOW WILL BE POSSIBLE BEFORE MIDNIGHT TONIGHT IN THE WESTERN OK
PANHANDLE AND FAR NW TX PANHANDLE. ACCUMULATIONS OF SNOW SHOULD BE
MINIMAL FROM THIS FIRST ROUND. BY NOON THURSDAY...A MUCH MORE
PRONOUNCED FRONTOGENETIC BAND OF SNOW SHOULD SET UP ROUGHLY FROM
HARTLEY COUNTY TO TEXAS COUNTY. ALL GUIDANCE IS IN FAIRLY GOOD
AGREEMENT ON THE PLACEMENT OF THIS BAND THROUGH TOMORROW AFTERNOON. A
POSSIBLE SECOND BAND SOUTHWARD SHIFT OF THE FIRST COULD BRING
INCREASED SNOW ACCUMULATIONS ALONG A LINE FROM VEGA TO BEAVER HEADING
INTO THE EVENING.
CURRENT THINKING HAS MOST SNOWFALL CLEARING FROM NORTHWEST TO
SOUTHEAST OVERNIGHT THURSDAY INTO FRIDAY...WITH THE LAST ACCUMULATING
SNOW FALLING IN THE SOUTHEAST TEXAS PANHANDLE BETWEEN MIDNIGHT FRIDAY
TO 6 AM THAT MORNING. SOME PERIODS OF FLURRIES COULD LINGER BEHIND
UNTIL DRIER MID LEVEL AIR FINALLY BUILDS OVER THE PANHANDLES.
OVERALL...WE ARE EXPECTING AVERAGE AMOUNTS OF 1 TO 3 INCHES OF SNOW
ACROSS THE PANHANDLES FROM TONIGHT THROUGH FRIDAY MORNING...WITH
LOCALLY HIGHER AMOUNTS UP TO 5 INCHES POSSIBLE UNDER HEAVIER SNOW
BANDS. A WINTER WEATHER ADVISORY WILL BE ISSUED TO ADDRESS THIS
SNOWFALL POTENTIAL.
NF
LONG TERM...FRIDAY THROUGH TUESDAY...
AS THE MAIN SHOT AT SNOW CLEARS THE AREA...THE MAIN STORY THROUGH THE
WEEKEND WILL BE THE PERSISTENT COLDER AIR IN PLACE THROUGH EARLY NEXT
WEEK. THINK NIGHTTIME LOWS IN THE LOW SINGLE DIGITS TO MID TEENS
WILL BE POSSIBLE MOST NIGHTS THROUGH THE MIDDLE OF NEXT WEEK...WITH
DAYTIME HIGHS IN THE TEENS AND TWENTIES THROUGH SATURDAY.
SOUTHWESTERLY WINDS ON SUNDAY MAY HELP TO BRING TEMPERATURES UP TO
NEAR FREEZING...THOUGH THINK CLOUD COVER WILL KEEP MOST PLACES BELOW
FREEZING EVEN ON SUNDAY AND MONDAY. CURRENTLY THINK TUESDAY WILL BE
FIRST CHANCE TO CLIMB ABOVE THE FREEZING MARK. DANGEROUSLY COLD WIND
CHILLS BETWEEN ZERO AND 15 BELOW ZERO WILL BE POSSIBLE DURING THIS
TIME AS WELL.
CANNOT RULE OUT A SLIGHT CHANCE FOR LIGHT SNOW SATURDAY NIGHT INTO
SUNDAY...THOUGH AT THIS TIME THINK ANY ACCUMULATIONS WOULD BE LESS
THAN ONE HALF INCH.
NF
FIRE WEATHER...
ONLY A BRIEF PERIOD OF ELEVATED FIRE WEATHER CONDITIONS WILL BE
POSSIBLE THIS AFTERNOON IN THE FAR SOUTHWEST TEXAS PANHANDLE...SHOULD
THE COLD FRONT IN FACT RETREAT NORTHEAST DURING THE DAY.
OTHERWISE...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED THROUGH THE MIDDLE OF NEXT WEEK.
NF
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WINTER WEATHER ADVISORY FROM 3 PM THURSDAY TO 6 AM CST FRIDAY
FOR THE FOLLOWING ZONES: ARMSTRONG...CARSON...
COLLINGSWORTH...DEAF SMITH...DONLEY...GRAY...HANSFORD...
HEMPHILL...HUTCHINSON...LIPSCOMB...MOORE...OCHILTREE...
OLDHAM...POTTER...RANDALL...ROBERTS...WHEELER.
WINTER WEATHER ADVISORY FROM 4 AM THURSDAY TO MIDNIGHT CST
THURSDAY NIGHT FOR THE FOLLOWING ZONES: DALLAM...HARTLEY...
SHERMAN.
OK...WINTER WEATHER ADVISORY FROM 3 PM THURSDAY TO 6 AM CST FRIDAY
FOR THE FOLLOWING ZONES: BEAVER.
WINTER WEATHER ADVISORY FROM 4 AM THURSDAY TO MIDNIGHT CST
THURSDAY NIGHT FOR THE FOLLOWING ZONES: CIMARRON...TEXAS.
&&
$$
10/16
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
841 AM CST Wed Dec 4 2013
.UPDATE...
Updated temperatures and winds across the northern Big Country.
&&
.DISCUSSION...
Initial cold front has dropped into the northern Big Country
counties of Haskell and Throckmorton. Latest RUC and NAM data
suggests that the temperatures behind the front will still climb
today, but just not as fast. Have lowered afternoon highs and
adjusted temperatures and winds for the rest of the day.
Models suggest the front will approach Abilene this afternoon and
then stall. Will not bring it in at this point, but will continue to
monitor.
&&
.PREV DISCUSSION... /ISSUED 558 AM CST WED DEC 4 2013/
AVIATION...
/12Z TAFS/
Expect VFR conditions at the terminals during the next 24 hours as
high clouds stream northeast across West Central Texas. The winds
will be southwest to west with gusts to near 20 knots this
afternoon. Also, a cold front will move to just south of the I-20
corridor by late tonight, and have shifted the wind to the north at
the KABI terminal after 06Z Thursday.
21
PREV DISCUSSION... /ISSUED 510 AM CST WED DEC 4 2013/
SHORT TERM...
Today
Look for one more day of unseasonably warm afternoon highs.
Temperatures at 850 mb increase again this afternoon across West
Central Texas. Although cloud cover will be increasing today, gusty
west, down-slope, winds will help push afternoon highs into the mid
to upper 70s across the Big Country and into the 80 to 85 range
elsewhere.
Huber
Tonight
Another strong cold front will move into the Big country around
midnight tonight. The NAM continues to be faster than the GFS. Our
wind grids reflect a timing closer to the faster NAM; thus, I expect
north surface winds to dominate the Big Country north of Interstate
20 by midnight tonight. Thus, lows there tonight will be mainly in
the 30 to 35 range. Elsewhere, 40s look good.
Huber
Thursday through Friday night
Unseasonably cold temperatures and a wintry precipitation mix will
dominate the remainder of the short term. Well, we`ve closely
watched the models develop this next arctic system for the last
several days, and we`re becoming more confident with accumulations
of sleet or freezing rain which may exceed our one quarter inch
warning threshold, mainly across the Big Country. I did note model
forecast sounding are indicating much deeper saturation in the
column, as compared to this time last night. So, with greater
confidence for significant accumulation, we have a Winter Storm
Watch in effect for all our Big Country counties. The latest
Weather Prediction Center guidance indicates possible
accumulations across mainly our Big Country counties of at least
one quarter inch. Elsewhere across West Central Texas, my
confidence is not as high for any accumulations close to one
quarter inch. Thus, we will continue a Special Weather Statement
for our remaining counties. The best chance for precipitation will
be Thursday night, as an upper trough moves over the region. As if
the ice and sleet accumulations weren`t enough, I`m also concerned
about temperatures Thursday night and corresponding wind chill,
especially across the Big Country. With lows in the teens there,
gusty north winds will create very dangerous wind chill numbers
around zero degrees. On Friday, strong cold air advection
continues, with surface winds from the north around 15 mph. The
wintry precipitation mix will continue until around noon; then,
the upper trough axis moves east of our area. Overnight Friday
night, very dangerous wind chill numbers will again dominate the
Big Country and even parts of the Concho valley and Heartland.
With north surface winds continuing Friday night, cold air
advection will create colder lows than Thursday night.
Huber
LONG TERM...
Saturday through Sunday
Unseasonably cold temperatures will continue through the weekend. As
a very dominate arctic airmass settles over Texas for the weekend,
unseasonably cold temperatures will continue. Highs Saturday will
likely remain at or just below freezing for most of West Central
Texas. Thus, any remaining ice will likely be slow to melt, if it
melts at all. Another short wave aloft will move across the southern
plains on Saturday and perhaps bring another brief round of wintry
precipitation to West central Texas. My confidence isn`t very high
regarding the potential for additional precipitation with this
secondary short wave; thus, I`ve continued only slight chance PoPs
for the Saturday period. As for temperatures, Sunday doesn`t look
much better. Returning sunshine Sunday will help lift temperatures
above the freezing mark for the afternoon hours. Nevertheless, highs
in the lower 30s for much of the Big Country on Sunday aren`t what
I`d call warm!
Huber
Sunday night through Tuesday
For the start of next week, temperatures do begin to rebound just
slightly; but, they remain well below seasonal normals.
Huber
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 76 34 34 17 28 / 5 30 60 70 30
San Angelo 82 44 44 25 33 / 5 20 50 70 20
Junction 84 49 49 31 35 / 10 20 40 70 30
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH from Thursday afternoon through Friday
morning FOR THE FOLLOWING ZONES: Callahan...Fisher...Haskell...
Jones...Nolan...Shackelford...Taylor...Throckmorton.
&&
$$
07
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
556 AM CST WED DEC 4 2013
.AVIATION...
FOR THE 12Z TAFS, THIS IS A LOW CONFIDENCE FORECAST.
A COLD FRONT HAS PASSED THROUGH ALL THE TERMINALS WITH N/NE WINDS
LIKELY TO CONTINUE THROUGH THE REMAINDER OF THIS TAF PERIOD. A
SECONDARY COLD FRONT WILL ARRIVE 00Z-03Z WITH NE WINDS GUSTING UP TO
25 KT.
THE MOST PROBLEMATIC ASPECT OF THIS FORECAST IS FLIGHT CATEGORIES,
AND FORECAST CONFIDENCE IS VERY LOW.
LLWS ASSOCIATED WITH THE COLD FRONT WILL CONTINUE AT KAMA AND KDHT
THROUGH 16Z WHEN WINDS WEAKEN ALOFT. DESPITE THE WEAKENING WINDS
ALOFT, THERE WILL STILL BE AT LEAST A 150 DEGREE WIND SHIFT WITHIN
THE LOWEST 2000 FT THROUGHOUT THIS TAF PERIOD.
-SN WILL BE POSSIBLE AT KDHT AND KGUY AFTER 09Z, BUT DRY AIR NEAR
THE SURFACE MAY ALLOW THIS TO HOLD OFF UNTIL AFTER THIS TAF PERIOD.
JACKSON
&&
.PREV DISCUSSION... /ISSUED 534 AM CST WED DEC 4 2013/
DISCUSSION...
THE ANTICIPATED COLD FRONT IS CURRENTLY WORKING SOUTH THROUGH THE
FORECAST AREA...WITH AN EXPECTED SURGE OF ARCTIC AIR LATER TODAY
PLUNGING THE PANHANDLES INTO SUBFREEZING TEMPERATURES THROUGH AT
LEAST THE WEEKEND. A PERIOD OF SNOWFALL WILL BE POSSIBLE FROM LATE
TONIGHT THROUGH EARLY FRIDAY MORNING. FURTHER CHANCES FOR LIGHT SNOW
MAY RETURN LATE IN THE WEEKEND.
SHORT TERM...TODAY THROUGH FRIDAY MORNING...
EVEN AT THIS LATE HOUR...THERE CONTINUES TO BE MODEL DISAGREEMENT
OVER THE TIMING AND POSITION OF THE COLD FRONT TODAY. AT LEAST AN
INITIAL SURGE HAS PUSHED THE FRONT TO THE SOUTH OF OUR CWA THIS
MORNING. THE LATEST RAP CONTINUES TO INDICATE A SLIGHT RETREAT OF THE
FRONT THIS AFTERNOON...ALLOWING FOR THE FAR SOUTHWEST TX PANHANDLE TO
WARM INTO THE UPPER 50S OR LOWER 60S. A FINAL SURGE OF COLD AIR
SHOULD PUSH THE FRONT SOUTH OF OUR AREA BY SUNSET TONIGHT. THEN...THE
ARCTIC AIR IS HERE TO STAY. NIGHTTIME LOWS IN THE LOW SINGLE DIGITS
TO MID TEENS...AND DAYTIME HIGHS IN THE TEENS TO 20S WILL BE POSSIBLE
FOLLOWING THE COLD FRONT.
LIGHT SNOW WILL BE POSSIBLE BEFORE MIDNIGHT TONIGHT IN THE WESTERN OK
PANHANDLE AND FAR NW TX PANHANDLE. ACCUMULATIONS OF SNOW SHOULD BE
MINIMAL FROM THIS FIRST ROUND. BY NOON THURSDAY...A MUCH MORE
PRONOUNCED FRONTOGENETIC BAND OF SNOW SHOULD SET UP ROUGHLY FROM
HARTLEY COUNTY TO TEXAS COUNTY. ALL GUIDANCE IS IN FAIRLY GOOD
AGREEMENT ON THE PLACEMENT OF THIS BAND THROUGH TOMORROW AFTERNOON. A
POSSIBLE SECOND BAND SOUTHWARD SHIFT OF THE FIRST COULD BRING
INCREASED SNOW ACCUMULATIONS ALONG A LINE FROM VEGA TO BEAVER HEADING
INTO THE EVENING.
CURRENT THINKING HAS MOST SNOWFALL CLEARING FROM NORTHWEST TO
SOUTHEAST OVERNIGHT THURSDAY INTO FRIDAY...WITH THE LAST ACCUMULATING
SNOW FALLING IN THE SOUTHEAST TEXAS PANHANDLE BETWEEN MIDNIGHT FRIDAY
TO 6 AM THAT MORNING. SOME PERIODS OF FLURRIES COULD LINGER BEHIND
UNTIL DRIER MID LEVEL AIR FINALLY BUILDS OVER THE PANHANDLES.
OVERALL...WE ARE EXPECTING AVERAGE AMOUNTS OF 1 TO 3 INCHES OF SNOW
ACROSS THE PANHANDLES FROM TONIGHT THROUGH FRIDAY MORNING...WITH
LOCALLY HIGHER AMOUNTS UP TO 5 INCHES POSSIBLE UNDER HEAVIER SNOW
BANDS. A WINTER WEATHER ADVISORY WILL BE ISSUED TO ADDRESS THIS
SNOWFALL POTENTIAL.
NF
LONG TERM...FRIDAY THROUGH TUESDAY...
AS THE MAIN SHOT AT SNOW CLEARS THE AREA...THE MAIN STORY THROUGH THE
WEEKEND WILL BE THE PERSISTENT COLDER AIR IN PLACE THROUGH EARLY NEXT
WEEK. THINK NIGHTTIME LOWS IN THE LOW SINGLE DIGITS TO MID TEENS
WILL BE POSSIBLE MOST NIGHTS THROUGH THE MIDDLE OF NEXT WEEK...WITH
DAYTIME HIGHS IN THE TEENS AND TWENTIES THROUGH SATURDAY.
SOUTHWESTERLY WINDS ON SUNDAY MAY HELP TO BRING TEMPERATURES UP TO
NEAR FREEZING...THOUGH THINK CLOUD COVER WILL KEEP MOST PLACES BELOW
FREEZING EVEN ON SUNDAY AND MONDAY. CURRENTLY THINK TUESDAY WILL BE
FIRST CHANCE TO CLIMB ABOVE THE FREEZING MARK. DANGEROUSLY COLD WIND
CHILLS BETWEEN ZERO AND 15 BELOW ZERO WILL BE POSSIBLE DURING THIS
TIME AS WELL.
CANNOT RULE OUT A SLIGHT CHANCE FOR LIGHT SNOW SATURDAY NIGHT INTO
SUNDAY...THOUGH AT THIS TIME THINK ANY ACCUMULATIONS WOULD BE LESS
THAN ONE HALF INCH.
NF
FIRE WEATHER...
ONLY A BRIEF PERIOD OF ELEVATED FIRE WEATHER CONDITIONS WILL BE
POSSIBLE THIS AFTERNOON IN THE FAR SOUTHWEST TEXAS PANHANDLE...SHOULD
THE COLD FRONT IN FACT RETREAT NORTHEAST DURING THE DAY.
OTHERWISE...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED THROUGH THE MIDDLE OF NEXT WEEK.
NF
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
NF/JJ
AREA FORECAST DISCUSSION
NWS AMARILLO TX
534 AM CST WED DEC 4 2013
.DISCUSSION...
THE ANTICIPATED COLD FRONT IS CURRENTLY WORKING SOUTH THROUGH THE
FORECAST AREA...WITH AN EXPECTED SURGE OF ARCTIC AIR LATER TODAY
PLUNGING THE PANHANDLES INTO SUBFREEZING TEMPERATURES THROUGH AT
LEAST THE WEEKEND. A PERIOD OF SNOWFALL WILL BE POSSIBLE FROM LATE
TONIGHT THROUGH EARLY FRIDAY MORNING. FURTHER CHANCES FOR LIGHT SNOW
MAY RETURN LATE IN THE WEEKEND.
&&
.SHORT TERM...TODAY THROUGH FRIDAY MORNING...
EVEN AT THIS LATE HOUR...THERE CONTINUES TO BE MODEL DISAGREEMENT
OVER THE TIMING AND POSITION OF THE COLD FRONT TODAY. AT LEAST AN
INITIAL SURGE HAS PUSHED THE FRONT TO THE SOUTH OF OUR CWA THIS
MORNING. THE LATEST RAP CONTINUES TO INDICATE A SLIGHT RETREAT OF THE
FRONT THIS AFTERNOON...ALLOWING FOR THE FAR SOUTHWEST TX PANHANDLE TO
WARM INTO THE UPPER 50S OR LOWER 60S. A FINAL SURGE OF COLD AIR
SHOULD PUSH THE FRONT SOUTH OF OUR AREA BY SUNSET TONIGHT. THEN...THE
ARCTIC AIR IS HERE TO STAY. NIGHTTIME LOWS IN THE LOW SINGLE DIGITS
TO MID TEENS...AND DAYTIME HIGHS IN THE TEENS TO 20S WILL BE POSSIBLE
FOLLOWING THE COLD FRONT.
LIGHT SNOW WILL BE POSSIBLE BEFORE MIDNIGHT TONIGHT IN THE WESTERN OK
PANHANDLE AND FAR NW TX PANHANDLE. ACCUMULATIONS OF SNOW SHOULD BE
MINIMAL FROM THIS FIRST ROUND. BY NOON THURSDAY...A MUCH MORE
PRONOUNCED FRONTOGENETIC BAND OF SNOW SHOULD SET UP ROUGHLY FROM
HARTLEY COUNTY TO TEXAS COUNTY. ALL GUIDANCE IS IN FAIRLY GOOD
AGREEMENT ON THE PLACEMENT OF THIS BAND THROUGH TOMORROW AFTERNOON. A
POSSIBLE SECOND BAND SOUTHWARD SHIFT OF THE FIRST COULD BRING
INCREASED SNOW ACCUMULATIONS ALONG A LINE FROM VEGA TO BEAVER HEADING
INTO THE EVENING.
CURRENT THINKING HAS MOST SNOWFALL CLEARING FROM NORTHWEST TO
SOUTHEAST OVERNIGHT THURSDAY INTO FRIDAY...WITH THE LAST ACCUMULATING
SNOW FALLING IN THE SOUTHEAST TEXAS PANHANDLE BETWEEN MIDNIGHT FRIDAY
TO 6 AM THAT MORNING. SOME PERIODS OF FLURRIES COULD LINGER BEHIND
UNTIL DRIER MID LEVEL AIR FINALLY BUILDS OVER THE PANHANDLES.
OVERALL...WE ARE EXPECTING AVERAGE AMOUNTS OF 1 TO 3 INCHES OF SNOW
ACROSS THE PANHANDLES FROM TONIGHT THROUGH FRIDAY MORNING...WITH
LOCALLY HIGHER AMOUNTS UP TO 5 INCHES POSSIBLE UNDER HEAVIER SNOW
BANDS. A WINTER WEATHER ADVISORY WILL BE ISSUED TO ADDRESS THIS
SNOWFALL POTENTIAL.
NF
.LONG TERM...FRIDAY THROUGH TUESDAY...
AS THE MAIN SHOT AT SNOW CLEARS THE AREA...THE MAIN STORY THROUGH THE
WEEKEND WILL BE THE PERSISTENT COLDER AIR IN PLACE THROUGH EARLY NEXT
WEEK. THINK NIGHTTIME LOWS IN THE LOW SINGLE DIGITS TO MID TEENS
WILL BE POSSIBLE MOST NIGHTS THROUGH THE MIDDLE OF NEXT WEEK...WITH
DAYTIME HIGHS IN THE TEENS AND TWENTIES THROUGH SATURDAY.
SOUTHWESTERLY WINDS ON SUNDAY MAY HELP TO BRING TEMPERATURES UP TO
NEAR FREEZING...THOUGH THINK CLOUD COVER WILL KEEP MOST PLACES BELOW
FREEZING EVEN ON SUNDAY AND MONDAY. CURRENTLY THINK TUESDAY WILL BE
FIRST CHANCE TO CLIMB ABOVE THE FREEZING MARK. DANGEROUSLY COLD WIND
CHILLS BETWEEN ZERO AND 15 BELOW ZERO WILL BE POSSIBLE DURING THIS
TIME AS WELL.
CANNOT RULE OUT A SLIGHT CHANCE FOR LIGHT SNOW SATURDAY NIGHT INTO
SUNDAY...THOUGH AT THIS TIME THINK ANY ACCUMULATIONS WOULD BE LESS
THAN ONE HALF INCH.
NF
&&
.FIRE WEATHER...
ONLY A BRIEF PERIOD OF ELEVATED FIRE WEATHER CONDITIONS WILL BE
POSSIBLE THIS AFTERNOON IN THE FAR SOUTHWEST TEXAS PANHANDLE...SHOULD
THE COLD FRONT IN FACT RETREAT NORTHEAST DURING THE DAY.
OTHERWISE...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED THROUGH THE MIDDLE OF NEXT WEEK.
NF
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 54 13 18 11 17 / 5 10 30 50 10
BEAVER OK 30 12 19 9 19 / 5 10 50 30 10
BOISE CITY OK 25 7 12 5 13 / 5 30 50 40 10
BORGER TX 35 13 19 12 18 / 5 10 30 60 10
BOYS RANCH TX 50 15 18 12 19 / 5 20 40 40 10
CANYON TX 65 15 20 11 19 / 5 10 20 50 10
CLARENDON TX 52 17 22 15 22 / 0 10 10 30 10
DALHART TX 30 9 14 7 15 / 5 20 60 40 10
GUYMON OK 28 10 15 9 15 / 5 20 60 30 10
HEREFORD TX 66 15 21 11 20 / 5 10 30 50 10
LIPSCOMB TX 32 12 21 11 21 / 0 10 20 60 10
PAMPA TX 39 13 19 11 19 / 5 10 20 60 10
SHAMROCK TX 48 17 24 15 24 / 0 10 10 30 10
WELLINGTON TX 52 20 25 17 24 / 0 10 10 30 10
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
13/06
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1152 PM CST TUE DEC 3 2013
.AVIATION...
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. A COLD
FRONT MOVING SOUTH OUT OF THE PANHANDLES WILL BRING A NORTHERLY
WIND SHIFT TO KCDS THIS MORNING...WHILE SW WINDS WILL BECOME
BREEZY AT KLBB..SUSTAINED AROUND 15 TO 20 KTS. WINDS WILL DIMINISH
THIS EVENING WHILE A STRONGER FROPA APPROACHES TOWARD THE END OF
THE FORECAST. CLOUD COVER SHOULD BE CONFINED TO HEIGHTS AOA 20K FT
THROUGH 06 UTC...ALTHOUGH LOW STRATUS MAY BE APPROACHING KCDS BY
THAT TIME.
&&
.PREV DISCUSSION... /ISSUED 955 PM CST TUE DEC 3 2013/
UPDATE...
THE COLD FRONT AT 930 PM HAD ALMOST CLEARED SE COLORADO AND WRN
KANSAS AS IT RACES TOWARD THE PANHANDLES. THIS APPEARS TO BE
A FEW HOURS FASTER THAN MODEL PROJECTIONS. THE RAP NOW HAS THE
LEADING EDGE OF THE FRONT INTO THE CHILDRESS AREA BY 11 UTC/5
AM...ABOUT 3 HOURS EARLIER THAN PREVIOUS INDICATIONS. WITH THIS IN
MIND...THE FRONT MAY MAKE BETTER PROGRESS THROUGH THE CWFA BEFORE
STALLING OUT LATE MORNING OR MIDDAY WED. IN FACT...IT IS NOT OUT OF
THE QUESTION THE WIND SHIFT COULD MAKE IT INTO THE CENTRAL SOUTH
PLAINS...ALTHOUGH ALL AVAILABLE GUIDANCE STILL SHOWS SW BREEZES
OUT-DUELING THE FRONT AND LEADING TO A WARM AFTERNOON FOR MOST OF
THE CAPROCK. THEN THE FRONT WILL BLAST THROUGH THE ENTIRE CFWA
WEDNESDAY NIGHT.
THE 00 UTC NAM AND LATEST TTU-WRF AND SREF ALL SUGGEST THAT A
SHORTWAVE APPROACHING FROM THE SW WILL ENHANCE LIFT OVER THE COLD
AIR EARLY THURS MORNING. HOWEVER...AS PREVIOUS DISCUSSION
MENTIONED...MUCH OF THE INITIAL LIFT WILL GO TO SATURATING THE
INITIALLY DRY LOWER-LEVELS AND IT IS UNCERTAIN HOW MUCH PRECIP CAN
ACTUALLY GET WRUNG OUT BEFORE THE FIRST WAVE EXITS MIDDAY. MOST MODEL
PROGS SUGGEST THE BEST PRECIP POTENTIAL WILL BE ACROSS SRN AREAS
WITH THIS FIRST BATCH OF LIFT...WITH SOUNDINGS SHOWING A WINTRY MIX
OF SLEET AND SNOW FOR THE HIGHER ELEVATIONS AND SOME FREEZING RAIN
POTENTIAL OFF THE CAPROCK. THE BETTER CHANCES OF MORE SIGNIFICANT
FROZEN ACCUMULATIONS ARE STILL EXPECTED TO DEVELOP WITH THE
ARRIVAL OF THE MAIN UPPER WAVE THURS EVENING.
A WINTER STORM WATCH CONTINUES FOR THE ENTIRE CFWA BEGINNING 6 AM THURSDAY.
PREV DISCUSSION... /ISSUED 540 PM CST TUE DEC 3 2013/
AVIATION...
VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24 HOURS. A COLD FRONT
WITH A NORTHERLY WIND SHIFT IS EXPECTED TO ARRIVE AT KCDS AROUND
14 UTC. GUSTY WEST WINDS ARE EXPECTED AT KLBB DURING THE DAY...SUSTAINED
AT NEARLY 20 KTS....BEFORE SUBSIDING IN THE EVENING. CONSIDERABLE
UPPER-LEVEL CLOUDINESS WILL ALSO CONTINUE TO STREAM OVER THE AREA.
PREV DISCUSSION... /ISSUED 303 PM CST TUE DEC 3 2013/
SHORT TERM...
WEATHER PATTERN IS DOMINATED BY A HIGH AMPLITUDE RIDGE OFF THE WEST
COAST AND A STRONG LOW OVER MANITOBA...A SET-UP CONDUCIVE FOR
SHARPLY COLDER WEATHER...BUT MORE ON THAT IN THE LONG TERM. LEAD
WAVE IN A SERIES OF EMBEDDED DISTURBANCES ROTATING ABOUT
AFOREMENTIONED LOW WILL APPROACH WEDNESDAY EVENING AND WILL HELP
DRIVE INITIAL WIND SHIFT OF THE COLD-SPELL-TO-BE INTO OUR
NORTHEASTERN ZONES.
BREEZY CONDITIONS HAVE PERSISTED TODAY...PARTICULARLY ACROSS THE
NORTHERN ZONES ALONE WITH QUITE DRY LOW LEVELS LEADING TO ELEVATED
FIRE WEATHER CONDITIONS. ERC VALUES REMAIN ANEMIC ESPECIALLY WITH
THE EXTRA GROUND MOISTURE FROM THE LAST SNOW/ICE EVENT. INTO
WEDNESDAY...RH VALUES WILL BE ON THE RISE. FROM A SENSIBLE WEATHER
PERSPECTIVE...PLEASANTLY WARM CONDITIONS WILL PERSIST INTO WEDNESDAY
ALONG WITH INCREASING HIGH CLOUDINESS. THE WINDIEST
CONDITIONS...APPROACHING 20 KTS...SHOULD BE ACROSS THE SOUTHWESTERN
ZONES WELL DISPLACED FROM THE FRONTAL CONVERGENCE ZONE.
LONG TERM...
CERTAINTY IN THE FORECAST HAS INCREASED A BIT FROM THE PREVIOUS
SHIFT ALTHOUGH SOME SIGNIFICANT DIFFERENCES STILL REMAIN TO BE
NEGOTIATED AS THE EVENT DRAWS NEARER. MOIST ISENTROPIC LIFT WILL
BEGIN THURSDAY MORNING AND INCREASE THROUGH THE DAYTIME. GREATEST
LIFT WILL BE ACROSS NEW MEXICO INTO THE WESTERN PANHANDLE WHERE
THERE WILL BE AROUND 30KT OF FLOW ON THE ISENTROPIC SURFACES.
EARLY ON THURSDAY...MID AND UPPER LEVELS WILL BE MOIST AS A WEAK
SHORT WAVE MOVES OVER THE AREA OUT AHEAD OF THE MAIN TROUGH. DRY
AIR IN THE LOWER LEVELS OF THE ATMOSPHERE WILL HAVE TO BE OVERCOME
FOR SIGNIFICANT ACCUMULATIONS TO OCCUR. HOWEVER...BY THE TIME THE
ATMOSPHERE COMPLETELY SATURATES...DEEP LIFT WILL HAVE BEEN ERODED
WITH ONLY ISENTROPIC LIFT REMAINING. BY THE EVENING AS THE MAIN
TROUGH MOVES OUT OVER THE AREA...Q-VECTOR CONVERGENCE WILL BE
MAXIMIZED WITH A STRONG UPPER LEVEL JET. BY DAYBREAK ON
FRIDAY...ISENTROPIC DOWNGLIDE WILL BE RAPIDLY SWEEPING INTO THE
AREA BEHIND THE TROUGH SHUTTING DOWN PRECIPITATION.
ALTHOUGH...FRIDAY WILL LIKELY REMAIN CLOUDY WITH LOW LEVEL
MOISTURE GOING NO WHERE.
A WARM LAYER ALOFT WILL BE MOST PREVALENT NEAR THE SOUTHERN HALF
OF THE FA ADDING ANOTHER LAYER OF DIFFICULTY TO THE FORECAST. VERY
DRY SURFACE AIR MAY PREVENT MUCH PRECIPITATION OVER THE
SOUTHEASTERN TEXAS PANHANDLE EARLY IN THE EVENT ON THURSDAY. ON
THURSDAY...GENERALLY SNOW WILL BE THE PREFERRED PRECIPITATION TYPE
OVER THE SOUTHERN TEXAS PANHANDLE WITH LIGHT FREEZING PRECIPITATION
AND SLEET OVER THE SOUTH PLAINS AND ROLLING PLAINS. GIVEN THE FACT
THAT LIFT WILL ONLY BE COMING FROM ISENTROPIC LIFT...FREEZING
PRECIPITATION ACCUMULATIONS WILL LIKELY BE LIGHT. AS DEEPER LIFT
INCREASES ON THURSDAY NIGHT...THE COLUMN WILL COOL BELOW 0C FOR
MUCH OF THE AREA WITH THE EXCEPTION OF THE SOUTHERN ROLLING
PLAINS. HOWEVER...MID AND UPPER LEVEL DRY AIR WILL BE QUICKLY
WORKING INTO THE REGION FROM THE NORTHWEST ON THURSDAY EVENING. A
MOSTLY SNOW EVENT FOR THE NORTHERN AREAS DURING THURSDAY EVENING
THROUGH FRIDAY MORNING MAY TURN MORE INTO A WINTRY MIX. FREEZING
PRECIPITATION IS STILL THE LIKELY PRECIPITATION TYPE OVER THE
SOUTHERN ROLLING PLAINS. IN ADDITION TO THE WINTRY
PRECIPITATION...TEMPERATURES WILL BE VERY COLD WITH A STRONG
SURFACE RIDGE MOVING INTO THE CENTRAL US ALONG WITH STRONG
MERIDIONAL FLOW TAPING INTO ARCTIC AIR.
THE NEXT TROUGH WILL BE DIGGING INTO THE SOUTHWEST US ON SATURDAY
AND WILL GENERATE ADDITIONAL ISENTROPIC UPGLIDE ON SATURDAY. GIVEN
THE SHALLOW NATURE OF THE MOISTURE AND COLD
TEMPERATURES...FREEZING DRIZZLE APPEARS LIKELY ALTHOUGH
ACCUMULATIONS WILL BE EXTREMELY LIGHT. ANOTHER COLD BLAST MAY MAKE
ITS WAY DOWN INTO THE US AGAIN WITH THE POLAR VORTEX STILL
SPINNING OVER SOUTHERN CANADA AND NO LETTING UP ON THE STRONG
MERIDIONAL FLOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 38 62 20 25 10 / 0 0 10 50 60
TULIA 37 63 21 25 11 / 0 0 20 30 60
PLAINVIEW 38 66 22 26 13 / 0 0 30 30 60
LEVELLAND 42 67 28 30 16 / 0 0 30 40 60
LUBBOCK 40 69 27 29 16 / 0 0 30 50 60
DENVER CITY 43 65 34 37 17 / 0 0 20 50 60
BROWNFIELD 43 67 29 32 17 / 0 0 30 50 60
CHILDRESS 35 61 25 28 13 / 0 0 20 30 60
SPUR 41 73 26 29 14 / 0 0 30 50 60
ASPERMONT 43 76 27 30 16 / 0 0 40 50 60
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM THURSDAY MORNING THROUGH FRIDAY MORNING
FOR THE FOLLOWING ZONES: TXZ021>044.
&&
$$
33
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1125 PM CST TUE DEC 3 2013
.AVIATION...
/06Z TAFS/
CONCERNS...ARRIVAL OF FRONT AT THE DFW TAF SITES TOMORROW AFTERNOON.
AN ARCTIC FRONT IS QUICKLY MAKING ITS WAY DOWN THE PLAINS AND WILL
ARRIVE IN NORTH TEXAS SEVERAL HOURS SOONER THAN PREVIOUSLY
THOUGHT. THROUGH TONIGHT...SOUTH TO SOUTHWEST WINDS BELOW 10 KTS
WILL PREVAIL. IN THE DFW AREA...THE WINDS WILL BECOME MORE
WESTERLY AROUND 16Z. THE LEADING EDGE OF THE FRONT WILL SLOWLY
AND QUIETLY SEEP THROUGH DFW AROUND 20-21Z TOMORROW AFTERNOON.
THE WINDS MAY ACTUALLY BE LIGHT AND VARIABLE FOR A FEW HOURS AS
THE FRONT STALLS NEAR THE I-20 CORRIDOR BUT NORTH WINDS SHOULD
PREVAIL BY THE EVENING HOURS. WIND SPEEDS WILL INCREASE OVERNIGHT
WITH STRONGER WINDS BETWEEN 15-20 KTS ON THURSDAY.
THE FRONT WILL NOT REACH KACT IN THIS TAF PERIOD AND EXPECT SOUTH
TO SOUTHWEST WINDS TO PREVAIL THROUGH THE PERIOD. THE FRONT WILL
ARRIVE TOMORROW NIGHT...JUST BEYOND THE TIMING OF THIS TAF PERIOD.
IN THE EXTENDED...FROZEN PRECIPITATION NOW APPEARS MORE LIKELY AT
THE DFW TAF SITES AS EARLY AS THURSDAY EVENING AND IS A
POSSIBILITY AT WACO EARLY FRIDAY MORNING.
82/JLD
&&
.UPDATE...
THE MAIN UPDATE ISSUE OF INTEREST IS THAT WE HAVE EXPANDED THE
WINTER STORM WATCH TO COVER THE NW HALF OF NORTH TEXAS. BUT FOR
TONIGHTS FORECAST HAVE LOWERED TEMPERATURES IN A FEW AREAS WHERE
DRY AIR AND GOOD RADIATIONAL COOLING ARE EXPECTED. HAVE ALSO ADDED
A MENTION OF FOG TO THE EAST AND SOUTHEAST ZONES WHERE
TEMPERATURES WILL COOL TO REACH THE DEWPOINTS.
WITHOUT EVEN LOOKING AT THE MODEL DATA THE 0Z UPPER AIR ANALYSIS
FOREBODES AN OMINOUS SETUP FOR WINTER WEATHER FOR NORTH TEXAS. THE
UPPER PATTERN SUGGESTS THAT AT SOME POINT IN THE NEXT FEW
DAYS...EITHER THURSDAY NIGHT/FRIDAY AND/OR THIS WEEKEND THE
COMBINATION OF COLD AIR AND MOISTURE/LIFT ARE GOING TO COME INTO
PLAY TO CREATE A WINTRY MIX OVER MUCH OF THE AREA.
WHILE SURFACE TEMPS ARE THE GO-TO FOR SEEING HOW COLD AN AIR MASS
IS...IT IS ACTUALLY BETTER TO ANALYZE THE LOW-MID LEVEL TEMPS
UPSTREAM TO SEE HOW COLD THE AIR IS THERE. THIS IS BECAUSE AIR
BEHIND A COLD FRONT UNDERGOES SLOW SUBSIDENCE AS IT MAKES ITS WAY
SOUTH FROM THE ARCTIC. BACKWARD TRAJECTORIES OF PAST COLD FRONTS
SHOW US TO CHECK 500-700MB TEMPS IN THE ARCTIC REGION SEVERAL DAYS
OUT...AND 700-850MB TEMPS ACROSS SOUTHERN CANADA 2 TO 3 DAYS OUT
TO GET A ROUGH IDEA ON HOW COLD IT IS GOING TO GET. THUS IT IS
CONCERNING THAT THE UPPER AIR ANALYSIS FROM 00Z REVEALS
EXCEPTIONALLY COLD AIR AT 700MB-850MB ACROSS MONTANA AND INTO
ALBERTA. GREAT FALLS MONTANA HAD A 700MB TEMP OF -24C AND -20C AT
850MB. THESE TEMPS ARE RUNNING 2 TO 3 STANDARD DEVIATIONS BELOW
NORMAL...WHICH IS AKIN TO SAYING THIS WOULD BE NEAR RECORD COLD
IF WE KEPT RECORDS AT THIS POINT IN SPACE. MODEL GUIDANCE HAS BEEN
2-4 DEG C TOO WARM WITH 6-12 HOUR FORECAST TEMPS AT THIS LEVEL AS
WELL...BUT IS BEGINNING TO CATCH ON.
MEANWHILE THE SURFACE ANALYSIS IS SHOWING THE COLD FRONT
BARRELING SOUTH THROUGH THE PLAINS...AND AHEAD OF SCHEDULE...NOW
CROSSING THROUGH MOST OF WESTERN KANSAS. ALL MODELS EXCEPT FOR THE
RAP/NAM ARE MUCH TOO SLOW IN THEIR 3-6 HOUR FORECASTS. THIS IS A
COMMON ISSUE WITH ARCTIC FRONTS WHEN THE 500MB PATTERN IS SITUATED
IN THIS FASHION. LEE SIDE COLD AIR DAMMING IN THE FRONT RANGE OF
THE ROCKIES CAUSES THE SURFACE HIGH TO BUILD FARTHER SOUTH AND
ALLOWS FOR STRONGER EQUATOR-WARD TRANSPORT OF ARCTIC AIR THAN
FORECAST. HIGH RESOLUTION MODELS DO A BETTER JOB AT FORECASTING
THIS...AND THE NAM/WRF MODELS ARE ABOUT THE BEST WE HAVE IN THE
SHORT-MEDIUM TIME RANGE. THE RAP IS EXCELLENT IN THIS SITUATION AS
WELL...BUT ONLY GOES OUT 18 HOURS. THE NAM AND RAP MODELS ARE
INDICATING THE FRONT WILL REACH THE NORTHWEST ZONES AFTER
SUNRISE...AND WILL LIKELY STALL ALONG OR JUST NORTH OF THE I-20
CORRIDOR WEDNESDAY AFTERNOON. THE AIR BEHIND THIS FRONT WILL BE
VERY SHALLOW...AND SUNSHINE WILL MODERATE THE LEADING EDGE OF THIS
AIR GREATLY. THUS HAVE BUMPED UP THE TIMING OF THE FRONT SEVERAL
HOURS AND LOWERED HIGHS INTO THE 60S IN THE NORTHERN ZONES.
WOULD NOT BE SURPRISED TO SEE THE FRONT MOVE THROUGH THE METROPLEX
IN THE AFTERNOON HOURS BUT AGAIN...THE CHANGE IN TEMPS AND WINDS
WILL NOT BE ALL THAT DRASTIC AT FIRST. THE REAL COLD AIR WILL
GRADUALLY INVADE THE REGION THROUGH THE OVERNIGHT HOURS.
THE NEW 00Z NAM HAS COME IN COLDER THURSDAY...AND ESSENTIALLY ALL
GUIDANCE BUT THE SREF IS INDICATING TEMPERATURES NEAR FREEZING
ACROSS THE NORTHWEST ZONES THURSDAY AFTERNOON AS PRECIPITATION
BEGINS TO DEVELOP. SINCE THE AIR IS SO COLD UPSTREAM IN THE SOURCE
REGION...AND THESE FRONTS TEND TO RUN A LITTLE COLDER THAN
MODEL FORECASTS...HAVE BUMPED UP THE TIMING OF THE FREEZING RAIN
AND WINTER STORM WATCH TO THURSDAY AFTERNOON OVER THE NORTHWEST
ZONES. IT IS TOO TOUGH TO SAY WHETHER IMPACTS WILL BEGIN
IMMEDIATELY THURSDAY AFTERNOON...BUT FELT THAT THE WATCH STARTING
AT 0Z WAS CUTTING IT TOO CLOSE.
AGAIN THERE IS GOOD MODEL AGREEMENT REGARDING THE FORECAST FOR
THURSDAY NIGHT AND FRIDAY. HAVE NOT CHANGED ANY OF THE FORECASTED
SENSIBLE WEATHER FROM THE PREVIOUS FORECAST AS IT ALL LOOKS
GOOD. HOWEVER...THERE MAY END UP BEING MORE SLEET THAN FREEZING
RAIN OVER THE NORTHWEST ZONES BUT IT IS TOO EARLY TO TELL FOR
SURE. HOWEVER PLACING A PERCENT LIKELIHOOD OF WINTER STORM WARNING
CRITERIA BEING MET IS TOUGH AT THIS POINT. WPC NOW INDICATES THE
DFW METROPLEX AND NORTHEAST INTO PARIS HAVE A 50-60 PERCENT CHANCE
OF A QUARTER INCH OF ICE ACCUMULATION THURSDAY NIGHT AND FRIDAY
MORNING. WATCH CRITERIA THRESHOLD IS A 50 PERCENT CONFIDENCE LEVEL
WHILE WARNING IS 80 PERCENT. SO GOING BY THIS PIECE OF GUIDANCE WE
SHOULD ISSUE A WATCH NOW. HOWEVER IT IS CONCERNING THE SREF IS
STILL FORECASTING A MARGINAL FREEZING RAIN EVENT FOR THIS REGION
WHICH LOWERS OUR CONFIDENCE. IT IS ALSO CONCERNING THAT THE WARM
NOSE WILL BE VERY WARM...AND RAIN DROPS WILL LIKELY TRANSPORT WARM
AIR TO THE SURFACE...WHICH WOULD INHIBIT ICE ACCUMULATION AND
IMPACTS. ON THE FLIP SIDE IT IS VERY CONCERNING THAT THE AIR
TEMPERATURES MAY STAY BELOW FREEZING FOR MUCH OF THE CWA FRIDAY
AND SATURDAY WITH CLOUDY SKIES. THIS MEANS IF ICE AND/OR SLEET IS
SIGNIFICANT THURSDAY NIGHT AND FRIDAY MORNING...ICE ON ROADS MAY
LINGER INTO SATURDAY OR SUNDAY WHEN COINCIDENTALLY ANOTHER SHOT AT
WINTER PRECIP ARRIVES. THE ISSUE IS THAT THIS EVENT UNLIKE THE
LAST MARGINAL/NON-EVENT DOES HAVE THE POTENTIAL FOR PROLONGED
WINTRY IMPACTS WHICH IS MORE REASON TO RAISE PUBLIC AWARENESS NOW
AND GO AHEAD AND EXPAND THE WATCH SOUTHEASTWARD TO INCLUDE MORE
AREA.
NOTE THIS DOES NOT MEAN THE ENTIRE WATCH AREA WILL BE UPGRADED TO
A WARNING...BUT AT THIS POINT WE BELIEVE THE ENTIRE WATCH AREA
WILL BE IN AT LEAST A WINTER WEATHER ADVISORY THURSDAY NIGHT AND
FRIDAY MORNING. IT IS TOO EARLY TO FINE TUNE ACCUMULATION AMOUNTS
OR ENTERTAIN WHO WILL SEE WHAT IMPACTS...AND THOSE WILL COME LATER
AS CONFIDENCE INCREASES FURTHER.
TR.92
&&
.PREV DISCUSSION... /ISSUED 356 PM CST TUE DEC 3 2013/
WE ARE ISSUING A WINTER STORM WATCH FROM AREAS ALONG AND NORTHWEST
OF A BRECKENRIDGE TO GAINESVILLE LINE FOR THURSDAY NIGHT THROUGH
FRIDAY. CONFIDENCE IS HIGH ENOUGH WITHIN THIS AREA TO MEET
WARNING CRITERIA OF 1/4 INCH OR MORE OF ICE.
THE ARCTIC FRONT WILL MOVE SOUTH OF THE RED RIVER WEDNESDAY
EVENING AND OUT OF THE SOUTHERN COUNTIES BY MIDDAY THURSDAY.
TEMPERATURES WILL FALL RAPIDLY BEHIND THE FRONT AS TEMPERATURES
UPSTREAM ARE IN THE LOW TEENS OVER WYOMING AND IN THE SINGLE
DIGITS IN CANADA.
PRECIPITATION WILL BE MOSTLY POST-FRONTAL THURSDAY NIGHT-FRIDAY
WITH MODERATE RAINFALL POSSIBLE ALONG A COMANCHE TO PARIS LINE
WHERE RICK ELEVATED MOISTURE MOVES OVER THE ELEVATED FRONTAL
BOUNDARY. THE RAIN WILL CHANGE TO FREEZING RAIN OVER THE
NORTHWEST COUNTIES THURSDAY EVENING AND PROGRESS SOUTHEASTWARD
WITH THE 32F ISOTHERM TO NEAR A SULPHUR SPRINGS TO GOLDTHWAITE
LINE ON FRIDAY. DUE TO UNCERTAINTY IN THE DEPTH OF THE COLD
AIR...WARM SOILS/STREETS...LATENT HEAT RELEASE OF RESIDUAL WATER
FROM RAINFALL AND THE STRENGTH OF THE WARM NOSE ALOFT...THE
LOCATION OF THE RAIN/FREEZING RAIN TRANSITION ZONE WAS HARD TO
DETERMINE... BUT CONFIDENCE WAS HIGH ENOUGH TO ISSUE A WATCH FOR
THE NORTHWEST COUNTIES WITH THIS PACKAGE. THE WATCH MAY BE PUSHED
FURTHER SOUTHEAST IF FUTURE MODEL RUNS PRODUCE HIGHER CONFIDENCE
THAT SIGNIFICANT ICE ACCUMULATIONS WILL OCCUR ELSEWHERE.
THERE WILL BE A LULL IN THE PRECIPITATION FRIDAY NIGHT AS THE
UPPER DISTURBANCE MOVES EAST OF THE REGION. ISENTROPIC UPGLIDE AND
ANOTHER UPPER DISTURBANCE WILL BRING PRECIPITATION BACK TO THE
REGION SATURDAY THROUGH SUNDAY. THIS PRECIPITATION WILL BE LIGHTER
THAN THE PREVIOUS ROUND...BUT WILL BE SLEET AND FREEZING RAIN
DURING THE OVERNIGHT HOURS...BUT GENERALLY LIQUID WHERE DAYTIME
TEMPS WARM ABOVE FREEZING.
THIS WILL BE THE COLDEST AIR OF THE SEASON SO FAR WITH LOWS IN THE
TEENS AND 20S ON SEVERAL NIGHTS. DAYTIME TEMPS WILL TREND WARMER
SUNDAY AND MONDAY...BUT A REINFORCING SHOT OF ARCTIC AIR IS
EXPECTED TO SEND US BACK INTO THE ICEBOX BY TUESDAY MORNING.
75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 55 77 38 44 28 / 0 5 20 60 90
WACO, TX 49 80 50 52 31 / 0 5 20 50 90
PARIS, TX 49 74 39 45 29 / 0 5 20 70 90
DENTON, TX 49 72 36 39 26 / 0 5 20 60 80
MCKINNEY, TX 48 75 38 42 27 / 0 5 20 60 90
DALLAS, TX 56 79 38 45 28 / 0 5 20 60 90
TERRELL, TX 52 77 42 47 29 / 0 5 20 60 90
CORSICANA, TX 54 77 50 50 31 / 0 5 20 60 90
TEMPLE, TX 52 81 56 56 32 / 0 5 20 50 80
MINERAL WELLS, TX 47 76 36 40 25 / 0 5 20 60 80
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM THURSDAY EVENING THROUGH FRIDAY
AFTERNOON FOR TXZ094-095-104>107-118>120-130>133-141>144.
WINTER STORM WATCH FROM THURSDAY AFTERNOON THROUGH FRIDAY
AFTERNOON FOR TXZ091>093-100>103-115>117-129.
&&
$$
82/92
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
752 PM EST THU DEC 5 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT MOVES EAST INTO THE APPALACHIANS
TONIGHT. THE BOUNDARY CRAWLS ACROSS VIRGINIA ON FRIDAY. ARCTIC
HIGH PRESSURE WELL BEHIND THE FRONT WILL WEDGE SOUTH ALONG THE
MOUNTAINS SATURDAY...BEFORE INTERACTING WITH PRECIPITATION
RETURNING NORTH BY SUNDAY. SOUTHWESTERLY FLOW RETURNS MONDAY
BEFORE A STRONGER COLD FRONT ARRIVES LATE MONDAY NIGHT.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 745 PM EST THURSDAY...
A STRONG COLD FRONT LOCATED TO OUR WEST THIS AFTERNOON FROM CLE TO
LEX TO MEM WILL MOVE EAST TONIGHT INTO FRIDAY. WEAK SHORTWAVES MOVE
NORTHEAST IN THE WARM SECTION WILL RESULT IN SCATTERED SHOWERS.
INCREASED PROBABILITY OF PRECIPITATION IN THE FAR NORTHWEST COUNTY
WARNING AREA AND LEANED POPS THIS EVENING INTO TONIGHT TOWARDS A
BLEND OF THE LATEST RAP AND RNKWRFARW. THE GFS ALSO SHOWED SOME
LIGHT PRECIPITATION ALONG THE SOUTHERN BLUE RIDGE MOUNTAINS INTO
SOUTHERN VIRGINIA. THE MAIN BODY OF RAINFALL SHOULD REMAIN WILL
REMAIN TO OUR WEST TONIGHT.
A VERY WARM AND MUGGY OVERNIGHT EXPECTED WITH READINGS FROM
AROUND 50 DEGREES IN THE NORTHWEST MOUNTAINS TO THE LOWER 60S IN
THE SOUTHEAST.
SURFACE COLD FRONT WILL BE ENTERING THE MOUNTAINS FRIDAY WITH A WAVE
OF LOW PRESSURE WHICH DEVELOPS ALONG THE BOUNDARY AND RIPPLE
NORTHEAST ACROSS THE REGION. MAIN AXIS OF RAIN SHOULD BE FOCUSED
ALONG AND JUST WEST OF THE FRONTAL BOUNDARY FRIDAY. FELT THERE WAS
ENOUGH INSTABILITY TO INCLUDE THE MENTION OF AN ISOLATED
THUNDERSTORMS MAINLY WEST OF I77. PLAYED HIGH TEMPERATURES CLOSE
TO THE ADJMAVBC WITH VALUES FROM THE LOWER 50S IN THE MOUNTAINS TO
THE MID 70S IN THE PIEDMONT.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 315 PM EST THURSDAY...
NOT A LOT OF CHANGE EARLY ON WITH THE SLOW MOVING COLD FRONT AND
ASSOCIATED WAVE CROSSING THE REGION FROM THE NW FRIDAY NIGHT AND
SPILLING SOUTH OF THE AREA EARLY SATURDAY. MODELS AGAIN WEAKEN THE
AXIS OF LIFT ALONG/BEHIND THE FRONT FRIDAY EVENING WITH HEAVIEST QPF
AND HIGHEST POPS ALONG THE WESTERN SLOPES THROUGH LATE
EVENING...THEN LESS ALONG/EAST OF THE BLUE RIDGE EXCEPT SE WHERE THE
BOUNDARY MAY STALL AND THE LOW LEVEL NE FLOW MAY ENHANCE SHOWERS
LATE. STILL APPEARS ENOUGH MOISTURE ACROSS THE NW LATE FRIDAY NIGHT
TO WARRANT KEEPING IN SOME LIGHT MIX MENTION AT ELEVATION BUT
OVERALL THINK ANYTHING FROZEN AT THIS POINT QUITE SPOTTY ACROSS SE
WVA. COLD AIR WILL BE SLIDING IN FROM THE NORTH/WEST ALTHOUGH TEMPS
MAY ACTUALLY GET COLDER AFTER DAYBREAK SATURDAY WHEN THE BETTER 85H
COLD ADVECTION ARRIVES.
GUIDANCE HAS CONTINUED THE TREND FROM YESTERDAY IN PUSHING THE
DEEPER MOISTURE TO THE SE SATURDAY AS THE LARGE ARCTIC HIGH BUILDS
IN FROM THE NW AND INITIALLY GIVES THE MOISTURE A PUSH. MAY SEE THE
ENTIRE CWA GO DRY BY SATURDAY AFTERNOON BUT FOR NOW LEAVING IN SOME
POP MAINLY EASTERN HALF THROUGH MIDDAY AND MAINLY FAR SE LATE IN THE
DAY. COULD EVEN HAVE SOME CLEARING TAKE PLACE NW PENDING HOW STRONG
THE DRY ADVECTION IS SO CUT BACK ON CLOUD COVER SOME NORTH HALF
DURING THE AFTERNOON. HIGHS CHILLY WITH LOW LEVEL NORTH/NW FLOW WITH
TEMPS 30S WEST TO 40S/NEAR 50 FAR SOUTH.
MAIN CONCERN THEN WITH THE POTENTIAL FOR A SIGNIFICANT WINTER EVENT
FROM VERY LATE SAT NIGHT INTO SUNDAY AND PERHAPS SUNDAY NIGHT ACROSS
THE NORTH. LATEST GUIDANCE HAS AGAIN SLOWED THINGS UP A BIT WITH
LOTS OF COLD/DRY AIR SLIDING DOWN EAST OF THE BLUE RIDGE AS THE
STRONG WEDGE DEVELOPS WITH THE HIGH BUILDING FARTHER SOUTH. THIS
WILL MAKE FOR COLDER TEMPS SAT NIGHT BEFORE THICKENING CLOUDS AND
LIGHT PRECIP RETURN FROM THE SOUTH/SW AFTER MIDNIGHT PER ISENTROPIC
LIFT AHEAD OF ANOTHER WAVE HEADING UP WEST OF THE MOUNTAINS.
LATEST FORECAST SOUNDINGS SHOW DRY AIR HOLDING LONGER WITH PRECIP
NOT REACHING INTO THE SOUTHERN HALF OF THE AREA UNTIL AFTER MIDNIGHT
AND POINTS NORTH SUNDAY AROUND DAYBREAK. PRECIP THEN LOOKS TO
ACCELERATE INTO THE WEDGE SUNDAY MORNING FROM THE SW BUT REMAIN
INCONSISTENT IN QPF AMOUNTS WHICH ARE CRITICAL GIVEN COLDER PROFILES
FROM 12Z RUNS. HOWEVER MOST SHOWING THE BEST LIFT WITH A WARM
FRONT ALOFT TYPE FEATURE THAT DEVELOPS OVER THE CENTRAL/NORTHERN
CWA SUNDAY MORNING AND SHIFTS NORTH DURING THE AFTERNOON LEAVING
MORE SPOTTY NATURE PRECIP ELSW INTO SUNDAY EVENING. BOTH THE NAM
AND GFS ARE COLDER THAN THE EARLIER SOLNS WITH LESS OF A WARM NOSE
EARLY ON AND DEEPER LOW LEVEL COLD AIR SUPPORTIVE OF MORE OF A
SNOW/SLEET MIX AT THE ONSET ESPCLY HIWAY 460 NORTH. THUS INCLUDING
SOME LIGHT ACCUMULATIONS NW SUNDAY MORNING AS THINGS REMAIN BELOW
FREEZING AT 85H AND THINGS BECOME MORE ISOTHERMAL UNTIL THE
STRONGER WARM ADVECTION ARRIVES IN THE AFTERNOON. SOME SLEET ALSO
POSSIBLE ELSW AS THINGS WET BULB DOWN AT THE ONSET BUT THINKING
MORE OF A PROLONGED FREEZING RAIN EVENT ESPCLY SRN BLUE RIDGE AND
ACROSS THE VA COUNTIES SOUTH OF 460. WEDGE MAY BE ENOUGH TO FORCE
TEMPS DOWN ENOUGH TO PRODUCE SOME SPOTTY FZRA INTO NW NC BUT
HOLDING OFF GOING THAT COLD ATTM. OTRW FEW CHANGES TO HIGH POPS
SUNDAY WITH HIGH POPS FOR LOW QPF SUNDAY NIGHT WHEN THE GREENBRIER
VALLEY AND SRN SHENANDOAH VALLEY MAY HOLD ONTO FREEZING RAIN
OVERNIGHT. SINCE MOSTLY A 6TH PERIOD AND BEYOND EVENT...WILL HOLD
OFF ON HEADLINES FOR NOW AND KEEP MENTION IN THE HWO.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 350 PM EST THURSDAY...
COMPLICATED FORECAST CONTINUES THROUGH THE EXTENDED PERIODS AS
SOUTHWEST FLOW ALOFT CONTINUES ACROSS THE REGION AT THE SAME TIME
ARCTIC AIR CONTINUES TO STREAM SOUTHEASTWARD FROM WESTERN/CENTRAL
CANADA INTO THE CENTRAL AND EASTERN U.S. OUR REGION REMAINS ON OR
NEAR THE BOUNDARY BETWEEN THE ARCTIC AIR AND THE WARMER AIR TO THE
SOUTHEAST...HOWEVER...THROUGH THE LONGER TERM PERIODS IT APPEARS
THAT THE ARCTIC AIR WILL WIN OUT ACROSS OUR REGION AND THE FRONTAL
WILL FINALLY BE PUSHED INTO THE SE STATES AS THE UPPER FLOW
FINALLY BECOMES NW.
MON MORNING WE ARE STILL DEALING WITH THE END OF THE POTENTIAL
SIGNIFICANT ICING EVENT ADDRESSED IN THE SHORT TERM PERIODS AS THE
WEDGE BOUNDARY FINALLY LIFTS INTO NORTHERN VA. MODELS HAVE
CONTINUED TO TREND COLDER...WHICH REQUIRES HOLDING ONTO THE -FZRA
A FEW MORE HOURS INTO MID-MORNING MONDAY THAN EARLIER INDICATED.
WILL CHANGE ALL PRECIPITATION TO -RA BY 15Z MON AS THE FORECAST
AREA BRIEFLY MOVES INTO A WARM SECTOR SANDWICHED BETWEEN THE
RETREATING COLD AIR WEDGE AND THE NEXT SURGE OF ARCTIC AIR TO THE
WEST. THROUGH THE DAYLIGHT HOURS...WE SHOULD SEE ONLY LIQUID PCPN
ACROSS THE REGION.
BY 06Z TUE...THE NEXT SURGE OF ARCTIC AIR SHOULD MOVE INTO OUR WV
COUNTIES AND OUR FAR SW VA CONTINUES. GIVEN THE STRENGTH OF THIS
SECOND SURGE OF COLD AIR...WOULD EXPECT -RA TO QUICKLY CHANGE TO
-SN FROM WEST TO EAST DURING THE EVENING. AT THE SAME TIME...THE
DEEPER MOISTURE IS SHIFTING EAST INTO THE PIEDMONT WHERE AT THIS
POINT IT SHOULD STILL BE WARM ENOUGH FOR MOSTLY -RA. THUS...SNOW
ACCUMULATIONS OUTSIDE MOUNTAIN UPSLOPE -SHSN EASTERN WV...SHOULD
BE MINIMAL...BUT COULD NOT RULE OUT AN INCH OR SO IN SOME SPOTS
WEST OF I-81/I-77. THERE IS CONSIDERABLE DISCREPANCY BETWEEN THE
GFS/ECMWF IN THIS TIME FRAME...WITH THE ECMWF PUSHING THE MOISTURE
WELL EAST OF THE CWA BEFORE ANY APPRECIABLE COLD AIR MOVES INTO
THE REGION FROM THE WEST...WHILE THE GFS TRIES TO MOVE YET A THIRD
WAVE ALONG THE FRONTAL BOUNDARY ACROSS THE REGION FROM THE SW.
GIVEN THE OVERALL CONFLUENT FLOW IN THIS TIME FRAME...NOT
EXPECTING ANY SIGNIFICANT PCPN OR MORE IMPORTANTLY WINTER WX
ISSUES. AGAIN...HOWEVER...THERE WILL BE MOUNTAIN UPSLOPE
-SHSN...WITH MINOR SNOW ACCUMULATIONS EASTERN WV COUNTIES INTO FAR
SW VA AND THE NW NC MOUNTAINS.
FOR THE REMAINDER OF THE EXTENDED...AT THIS POINT IT APPEARS DRY.
THE CENTER OF THE ARCTIC AIR MASS DRIFTS OVER THE REGION BY THU
WITH A VERY DRY/COLD AIR MASS. AGAIN...THERE ARE CONSIDERABLE
DIFFERENCES BETWEEN THE ECMWF AND GFS WITH RESPECT TO TEMPERATURES
IN THIS TIME FRAME. GIVEN THE STRENGTH OF THIS ARCTIC AIR
MASS...HAVE LEANED HEAVILY TOWARD THE COLDER GFS. THE COLDEST DAY
SHOULD BE THU WHEN THE ARCTIC HIGH IS CENTERED RIGHT OVER THE CWA.
WOULD NOT BE THE LEAST SURPRISED TO SEE MIN TEMPERATURES IN THE
SINGLE DIGITS IN LOCATIONS SUCH AS LWB. HOWEVER...THE PREVAILING
WEST AS OPPOSED TO A STRONG NW-N FLOW ALOFT SHOULD RESULT IN THE
COLDER AIR REMAINING NORTH AND WEST OF THE CWA..SO WE SHOULD STAY
AOA 20 DEGREES FOR MINS ACROSS THE PIEDMONT. ANY PRECIPITATION
WED-FRI SHOULD BE CONFINED TO UPSLOPE MOUNTAIN -SHSN WITH DRIER
DOWNSLOPE WEST FLOW EAST OF THE ALLEGHANYS. EVEN ACROSS EASTERN
WV...SNOW ACCUMULATIONS SHOULD BE FAIRLY LIMITED WITH OVERALL
SNOW ACCUMULATIONS THERE EVEN AN INCH OR LESS.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
AS OF 745 PM EST THURSDAY...
STRONG COLD FRONT WILL BE APPROACHING FROM THE OHIO VALLEY THIS
AFTERNOON...STALLING WEST OF THE APPALACHIAN MOUNTAINS TONIGHT.
A BROAD BAND OF RAIN FROM CENTRAL PENNSYLVANIA TO CENTRAL
TENNESSEE WILL BRING RAIN WITH MVFR VISIBILITIES TO KLWB AND KBLF
TONIGHT. STRATUS AND FOG WITH SCATTERED SHOWERS IS EXPECTED FOR
THE REST OF THE AREA. CEILINGS WERE ALREADY MVFR AT 00Z/7PM. HIGH
CONFIDENCE THAT KROA...KBCB...KLYH AND KDAN WILL LOWER TO IFR OR
LIFR BY MIDNIGHT WITH MVFR FOG. LITTLE IMPROVEMENT IS EXPECTED ON
FRIDAY. CEILINGS WILL REMAIN IN THE IFR TO MVFR RANGE WITH RAIN
BECOMING MORE WIDESPREAD...ESPECIALLY IN THE AFTERNOON.
EXTENDED AVIATION...A COLD FRONT WILL MAKE SLOW PROGRESS ACROSS
THE AREA FRIDAY...RESULTING IN MVFR AND IFR CONDITIONS IN ADDITION
TO WIDESPREAD RAIN SHOWERS...BEFORE THE FRONT PASSES EAST FRIDAY
NIGHT INTO SATURDAY MORNING. MAY SEE A BRIEF IMPROVEMENT TO VFR ON
SATURDAY AS HIGH PRESSURE BUILDS IN FROM THE NORTH...HOWEVER IFR
WILL RETURN SATURDAY NIGHT AS ANOTHER SYSTEM APPROACHES FROM THE
SOUTHWEST...BRINGING FREEZING RAIN...SNOW AND SLEET TO THE AREA
SUNDAY. AN ARCTIC COLD FRONT WILL MOVE THROUGH ON
MONDAY...BRINGING A SLOW IMPROVEMENT TO VFR FOR TUESDAY.
HIGH PRESSURE IS EXPECTED TO PROVIDE FAIR WEATHER WITH VFR
CONDITIONS FROM TUESDAY THROUGH THURSDAY.
&&
.CLIMATE...
WARM TEMPERATURES THE NEXT COUPLE DAYS WILL APPROACH RECORDS AT THE
CLIMATE SITES. BELOW ARE THE CURRENT RECORDS.
DECEMBER 5 CURRENT RECORD HIGH TEMPERATURES (YEAR)
ROA76(2001)
LYH76(2001)
DAN 75(1982)
BCB70(2001)
BLF71(2001)
LWB68(2001)
DECEMBER 5 CURRENT RECORD HIGH MINIMUM TEMPERATURES (YEAR)
ROA58(1982)
LYH60(1982)
DAN57(1982)
BCB52(1982)
BLF55(1994)
LWB53(1994)
DECEMBER 6 CURRENT RECORD HIGH MINIMUM TEMPERATURES (YEAR)
ROA52(2011)
LYH52(2011)
DAN60(2011)
BCB51(2011)
BLF56(2011)
LWB 52 (1998)
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/KM
NEAR TERM...AMS/KK
SHORT TERM...JH
LONG TERM...RAB
AVIATION...AMS/KK
CLIMATE...CF
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
936 PM CST THU DEC 5 2013
.UPDATE...
NO BIG CHANGES TO PREVIOUS FORECAST EXCEPT TO NUDGE LOW TEMPS UP A
BIT WITH EDGE OF MID-HIGH LEVEL CLOUDS FROM SYSTEM TO THE SOUTH
PUSHING OVER REGION FROM TIME TO TIME. STILL LOOKING AT LOWS IN
THE SINGLE DIGITS INLAND...THOUGH A LITTLE CLOSER TO +10 THAN
PREVIOUS FORECAST...AND IN THE TEENS ALONG THE LAKE. OCCASIONALLY
GUSTY WEST-NORTHWEST WINDS WILL KEEP WIND CHILLS BETWEEN 0 AND 10
BELOW.
&&
.AVIATION/06Z TAFS/...
VFR THROUGH THE PERIOD WITH NORTHWEST WINDS IN THE 10 TO 20 KNOT
RANGE SLOWLY EASING THROUGH THE DAY AND INTO THE EVENING FRIDAY.
&&
.MARINE...
NO CHANGE TO CURRENT HEADLINE...THOUGH NEXT SHIFT MAY CANCEL AT
330 AM ISSUANCE IF DOWNWARD TREND ON LATEST NAM AND RAP FORECAST
SOUNDINGS PAN OUT. WILL LET THEM ASSESS FULL 00Z MODEL SUITE.
&&
.PREV DISCUSSION... /ISSUED 333 PM CST THU DEC 5 2013/
SHORT TERM...
TONIGHT AND FRIDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
A DRY ARCTIC AIRMASS WILL DOMINATE. 925 TEMPS DROP OFF TO -12 TO
-17C TONIGHT WITH SOME MIXING TO KEEP WINDS UP A BIT. SINGLE DIGIT
LOWS WILL BE COMMON ACRS SRN WI. MODELS TRY TO THICKEN UP THE
CIRRUS CANOPY RIDING SW/NE IN THE UPPER FLOW AND THIS APPEARS
PLAUSIBLE GIVEN UPSTREAM CLOUD TRENDS. NOT MUCH CHANGE INTO FRIDAY
WITH MORE COLD AND ONLY SOME MID/HIGH CLOUDS BRUSHING THE SOUTH.
HIGHS MOSTLY IN THE TEENS.
FRIDAY NIGHT THROUGH SATURDAY NIGHT...FORECAST CONFIDENCE HIGH
NWLY WINDS WILL MAINTAIN AN ARCTIC AIRMASS OVER SRN WI DURING THIS
PERIOD. A 1040 MB HIGH WILL FINALLY ARRIVE FOR SAT NT BUT MID TO
UPPER LEVEL CLOUDS WILL INCREASE DURING THE NIGHT AS WARM
ADVECTION BEGINS AHEAD OF A LARGE POLAR TROUGH MOVING INTO THE
CENTRAL AND SRN ROCKIES. SINGLE DIGIT LOWS WITH HIGHS IN THE TEENS
WILL CONTINUE.
LONG TERM...SUNDAY THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM
THE EXTENDED MODELS ARE IN FAIRLY GOOD AGREEMENT OF AN IMPRESSIVE
WARM ADVECTION PATTERN DEVELOPING SUN AND SUN NT WITH THE PASSAGE
OF THE SHORTWAVE TROUGH SUN NT. THE DENDRITE GROWTH ZONE IS
APPROXIMATELY 200 MB THICK WITH THIS SYSTEM BUT ALSO NOTICE THE
GREATEST LIFT IS ABOVE THE DENDRITE ZONE. LAKE ENHANCEMENT WILL
ALSO BE A FACTOR AND WILL FOCUS MORE OVER OZAUKEE AND SHEBOYGAN
COUNTIES AS LONG AS THE 1000-850 MB FLOW REMAINS SELY. TOOK A
MODEL CONSENSUS OF QPF WHICH YIELDED AROUND 0.20 INCHES AND
APPLIED A SNOW RATIO AROUND 17 OR 18 TO 1. THIS YIELDS SNOW TOTALS
OF 3-4 INCHES BUT THEN ADDED A COUPLE INCHES DUE TO LAKE
ENHANCEMENT OVER SHEBOYGAN AND OZAUKEE COUNTIES. THE DETAILS OF
THE 1000-850 MB ONSHORE FLOW WILL BE THE KEY TO THE PLACEMENT OF
THE LAKE ENHANCED SNOWS AND IT IS POSSIBLE WARNING CRITERIA COULD
BE REACHED.
NWLY FLOW ALOFT AND ARCTIC AIR TO CONTINUE THE REMAINDER OF THE
WEEK. A WEAK ALBERTA CLIPPER MAY BRING A LIGHT AMOUNT OF SNOW LATE
MON NT AND TUE. ARCTIC HIGH PRESSURE TO PREVAIL WED AND THU.
AVIATION/00Z TAFS/...TIGHT PRESSURE GRADIENT CONTINUES BETWEEN LOW
PRESSURE LIFTING NORTHEAST OF LAKE SUPERIOR AND HIGH PRESSURE IN THE
PLAINS. EXPECT THE WINDS TO EASE TONIGHT INTO FRIDAY AS THE GRADIENT
RELAXES A BIT. JUST SOME JET RELATED AC/CI RACING NEWD INTO SRN
WI FROM THE CENTRAL PLAINS.
MARINE...SMALL CRAFT ADVISORY CONDITIONS TONIGHT WITH BRISK WEST
WINDS. WINDS WILL SLOWLY DIMINISH TONIGHT AS THE STRONG LOW NEAR
LAKE SUPERIOR MOVES NORTHEAST TOWARD JAMES BAY CANADA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM CST FRIDAY FOR LMZ643>646.
&&
$$
UPDATE...REM
TONIGHT/FRIDAY AND AVIATION/MARINE...COLLAR
FRIDAY NIGHT THROUGH THURSDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
316 PM CST WED DEC 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY MORNING)
ISSUED AT 316 PM CST WED DEC 4 2013
MAIN FORECAST CONCERN IS ON DEPARTING WEATHER SYSTEM...FOLLOWED
BY THE ARCTIC AIR MASS SURGE.
AS OF 3 PM WEDNESDAY...SURFACE ANALYSIS SHOWED 998 MB LOW
PRESSURE CENTERED NEAR DECORAH IOWA...WITH A WARM FRONT SITUATED
FROM NEAR PRAIRIE DU CHIEN WISCONSIN EASTWARD INTO SOUTHERN
WISCONSIN. FINALLY...THE LEADING EDGE OF THE COLD AIR WAS ALONG
THE I-35 CORRIDOR IN MINNESOTA AND IOWA.
THE SURFACE LOW IS EXPECTED TO LIFT NORTHEAST TO NORTHERN WISCONSIN
LATER THIS EVENING...THEN OVER LAKE SUPERIOR BY MIDNIGHT. THE COLD
FRONT SHOULD MAKE A CLEAN SWEEP ACROSS THE ENTIRE FORECAST AREA BY
03Z. THE SURGE OF WARMER AIR AHEAD OF THE SURFACE LOW IS KEEPING
WINTER PRECIPITATION THREAT LOW AT THIS TIME BUT STILL PLENTY OF
1/4 SM VISIBILITIES OR LOWER. LOCATIONS WILL HAVE TO WAIT FOR THE
COLD FRONTAL PASSAGE FOR IMPROVED VISIBILITIES...AND AREAS EAST OF
THE MISSISSIPPI RIVER AND NORTH OF I-90 IN WISCONSIN WILL LIKELY
HANG ONTO THE REDUCED VISIBILITIES THE LONGEST.
AHEAD OF THE COLD FRONT...STRONG LOW LEVEL LIFT AND SATURATION
COMBINED WITH VERY LITTLE ICE SATURATION ALOFT WILL LIKELY LEAD TO
DRIZZLE. HIGH RES MODELS SUCH AS THE HRRR CAPTURE THIS FAIRLY WELL.
BEHIND THE COLD FRONT...TEMPERATURES QUICKLY FALL INTO THE UPPER 20S
TO NEAR 30 DEGREES. ALTHOUGH MOISTURE IS TRAPPED IN THE LOW-LEVEL
INVERSION...THE LIFT BEGINS TO DROP OFF BUT THERE IS LIKELY TO BE
A PERIOD OF FREEZING DRIZZLE. AS EVEN COLDER AIR WORKS IN
ALOFT...SATURATION IN THE ICE GROWTH LAYER RETURNS SO PRECIPITATION
COULD END AS SNOW FLURRIES OR SNOW SHOWERS...ESPECIALLY ACROSS
CENTRAL MINNESOTA...INTO NORTH CENTRAL WISCONSIN BEFORE TAPERING
OFF ALTOGETHER TOWARD MIDNIGHT. AS SUCH...THE WINTER WEATHER
ADVISORY FOR TAYLOR/CLARK COUNTIES WILL REMAIN IN PLACE BUT LIKELY
COULD BE ENDED TOWARD MIDNIGHT.
FOR THURSDAY MORNING...GOOD CONSENSUS THAT PLENTY OF MOISTURE
REMAINS TRAPPED IN THE LOW LEVELS...MAINLY CENTERED AROUND 900 MB.
LIFT IS VERY WEAK BUT THE SURGE OF ARCTIC AIR SHOULD PUT THE DGZ
CLOSER TO 900 MB. THIS SUPPORTS VERY LIGHT BUT OCCASIONAL TO PERIODS
OF SNOW FLURRIES ACROSS NORTH CENTRAL WISCONSIN...BECOMING MORE
SCATTERED CLOSER TO ROCHESTER AND LA CROSSE.
.LONG TERM...(THURSDAY THROUGH WEDNESDAY)
ISSUED AT 316 PM CST WED DEC 4 2013
HIGHLIGHTS IN THE LONG TERM ARE ARCTIC AIR MASS SURGES AND
ACCUMULATING SNOWFALL POTENTIAL SUNDAY NIGHT.
THE CURRENT STORM SYSTEM DEEPENS AND QUICKLY DEPARTS NORTHEAST OF
THE GREAT LAKES REGION THURSDAY WHILE THE WESTERN TWO-THIRDS OF THE
CONUS REMAINS UNDER THE INFLUENCE OF THE UPPER LEVEL LONGWAVE
TROUGH. AS WELL ADVERTISED PREVIOUSLY...THE ARCTIC AIR SURGE
BEGINS IN EARNEST THURSDAY AND FRIDAY AS NOTED BY 850 MB
TEMPERATURES FALLING FROM AN AVERAGE OF -8C 12Z THURSDAY...TO -17C
BY 18Z FRIDAY. 850 MB STANDARDIZED ANOMALIES FALL TO 2 TO 2.5
DEGREES BELOW NORMAL...WHICH IS NOT RECORD COLD TERRITORY BUT
CERTAINLY UNSEASONABLE FOR THIS TIME OF YEAR. THE FRESH SNOWPACK
ACROSS CENTRAL MINNESOTA INTO NORTH CENTRAL WISCONSIN IS LIKELY TO
KEEP TEMPERATURES ON THE LOWER SIDE OF GUIDANCE AS WELL. LATEST
SNOW DEPTH READINGS SHOW ANYWHERE FROM A FEW INCHES FROM SOUTH CENTRAL
MINNESOTA...TO ALMOST 10 INCHES IN TAYLOR COUNTY. FORECAST
TEMPERATURES WERE NUDGED DOWN SLIGHTLY BY A FEW DEGREES FROM
PREVIOUS FORECAST.
A NOTICEABLY COLDER DAY ON TAP THURSDAY...WITH HIGHS ONLY IN THE
TEENS TO LOWER 20S. STIFF NORTHWEST WINDS WILL MAKE FOR WIND CHILL
READINGS IN THE SINGLE DIGITS ABOVE ZERO AT TIMES FOR MUCH OF THE
DAY. EVEN COLDER TEMPERATURES ARE EXPECTED FRIDAY AND
SATURDAY...MAINLY SINGLE DIGITS TO TEENS. FOR REFERENCE...NORMAL
HIGHS FOR THIS TIME OF YEAR ARE IN THE UPPER 20S TO LOWER 30S AND
LOWS IN THE TEENS. AS FAR AS LOW TEMPERATURES GO...SEVERAL
MORNINGS OF SUB ZERO READINGS EXPECTED FOR PARTS OF SOUTHEAST
MINNESOTA INTO NORTH CENTRAL WISCONSIN WHILE THE REST OF THE AREA
SHOULD FALL INTO THE SINGLE DIGITS ABOVE ZERO.
A WIND CHILL ADVISORY IS LIKELY NEEDED FOR PARTS OF THE AREA FRIDAY
NIGHT INTO SATURDAY AS THE SURFACE HIGH PRESSURE DROPS SOUTH TO OUR
WEST. THIS KEEPS A 10 TO 15 MPH WIND DURING THE OVERNIGHT ACROSS THE
AREA...RESULTING IN WIND CHILL READINGS IN THE 15 TO 25 DEGREE BELOW
ZERO RANGE NORTH OF INTERSTATE 90.
FOR THE UPCOMING WEEKEND...SATURDAY LOOKS TO BE ANOTHER UNSEASONABLY
COLD BUT DRY DAY WITH HIGHS IN THE SINGLE DIGITS TO TEENS.
HOWEVER...ON SUNDAY WITH THE MAIN UPPER LEVEL TROUGH REMAINING IN
PLACE ACROSS THE WESTERN CONUS...ANOTHER PIECE OF UPPER LEVEL ENERGY
DIGS INTO THE SOUTHWEST U.S. WHICH IS EXPECTED TO ALLOW A SURFACE
LOW TO DEVELOP IN THE LEE SIDE OF THE ROCKIES. PREVIOUS MODEL
CYCLES...AND THE 04.12Z GUIDANCE CONTINUE TO SHOW VERY GOOD
AGREEMENT THIS FAR OUT WHICH BOOSTS CONFIDENCE DURING THIS PERIOD.
THE SURFACE LOW IS EXPECTED TO BE NEAR CENTRAL OKLAHOMA 18Z
SUNDAY...THEN MOVE TOWARD CENTRAL ILLINOIS BY 06Z MONDAY. ON THE
NORTHWEST SIDE...AN INVERTED SURFACE TROUGH COUPLED WITH THE UPPER
LEVEL ENERGY IS LIKELY TO PROVIDE PLENTY OF LIFT TO SUPPORT SNOW
ACROSS MUCH OF THE FORECAST AREA. PRECIPITATION CHANCES WERE BOOSTED
TO LIKELY ACROSS NORTHEAST IOWA INTO WESTERN AND SOUTHERN
WISCONSIN...AND INTO THE 40 TO 50 PERCENT RANGE ELSEWHERE. STILL TOO
EARLY TO SPECULATE ON SNOWFALL AMOUNTS...BUT IMPACTFUL WEATHER IS
LOOKING LIKELY SUNDAY AFTERNOON INTO MONDAY MORNING FOR PORTIONS
OF THE AREA.
IN THE WAKE OF THE LATE WEEKEND SYSTEM...ANOTHER SURGE OF ARCTIC AIR
WILL USHER IN EVEN COLDER AIR WITH 850 MB TEMPERATURES IN THE -20 TO
-25C RANGE. AIDED BY A POSSIBLE FRESH SNOWPACK...WIDESPREAD MORNING
TEMPERATURES IN THE SINGLE DIGITS BELOW ZERO ARE LIKELY WITH TEENS
BELOW ZERO POSSIBLE IN SPOTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1112 AM CST WED DEC 4 2013
LITTLE CHANGE IN CONDITIONS ARE EXPECTED TO OCCUR UNTIL THE COLD
FRONT MOVES THROUGH THIS AFTERNOON. THIS WILL KEEP THE CEILINGS
AND VISIBILITIES DOWN IN THE IFR CATEGORY THROUGH AT LEAST MID
AFTERNOON AT KRST AND TO AROUND 00Z AT KLSE. ONCE THE FRONT COMES
THROUGH AND THE WINDS COME AROUND TO THE WEST...THE VISIBILITY
WILL GRADUALLY INCREASE AND SHOULD JUMP TO VFR AS THE WINDS BECOME
SUSTAINED OVER 10 KNOTS WITH GUSTS BETWEEN 20 AND 30 KNOTS. LOOKS
LIKE THE LOW LEVEL MOISTURE WILL GET TRAPPED UNDER THE INVERSION
SO ONLY EXPECTING THE CEILINGS TO COME UP TO MVFR AT BEST. OUTSIDE
OF SOME DRIZZLE AHEAD OF THE FRONT...NOT EXPECTING A LOT OF
PRECIPITATION TO OCCUR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ032>034-
041>044-053>055-061.
WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR WIZ017-029.
MN...DENSE FOG ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ088-096.
IA...DENSE FOG ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ011-030.
&&
$$
SHORT TERM...ZT
LONG TERM...ZT
AVIATION...04
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1030 AM CST WED DEC 4 2013
NEW INFORMATION ADDED TO UPDATE SECTION
.UPDATE...
ISSUED AT 1030 AM CST WED DEC 4 2013
LOW PRESSURE SYSTEM WAS NEAR KIRKSVILLE MISSOURI AT 15Z.
BEST 3 HOURLY PRESSURE FALLS WERE OVER EAU CLAIRE SO THAT`S WHERE
THIS SYSTEM SHOULD BE HEADED IN THE NEXT SEVERAL HOURS. SURFACE
OBSERVATIONS SUGGEST THAT WARM AIR AROUND 850MB HAS MOVED INTO
NORTHERN WISCONSIN AND CAUSED A CHANGEOVER FROM SNOW TO FREEZING
RAIN OR SLEET SOUTH OF A RHINELANDER TO IRON MOUNTAIN LINE. MODELS
FORECAST 850MB TEMPERATURES TO CONTINUE CLIMBING WITH SOUTHERLY
FLOW SO BACKED OFF ON SNOW ACCUMULATIONS AND INCREASED AMOUNT OF
FREEZING RAIN AND FREEZING DRIZZLE. WILL EXTEND THE WINTER WEATHER
ADVISORY FOR MARATHON, LINCOLN AND LANGLADE COUNTIES THROUGH THE
AFTERNOON AS TEMPERATURES WILL BE SLOW TO CLIMB ABOVE FREEZING.
&&
.SHORT TERM...TODAY...TONIGHT...AND THURSDAY
ISSUED AT 427 AM CST WED DEC 4 2013
FOCUS IS ON PCPN TYPES AND AMOUNTS TODAY...THEN FALLING
TEMPERATURES TONIGHT AND THU.
MODELS ARE IN BETTER AGREEMENT TONIGHT...USED A BLEND...LEANING A
BIT MORE ON ECMWF FOR THIS PERIOD. MADE EARLIER CHANGE TO
HEADLINES WITH ISSUANCE OF WINTER WEATHER ADVISORY FOR CENTRAL WI
AS TEMPERATURES NOT MOVING ABOVE FREEZING...ACTUALLY DROPPED. LIGHT
PCPN CONTINUES TO LIFT NORTH INTO CWA. CALLS TO PORTAGE AND WOOD
COUNTIES INDICATED ICING ISSUES ON ROADS. LOOKING FOR
TEMPERATURES TO MOVE ABOVE FREEZING MID MORNING.
RADAR MOSAIC SHOWING AREA OF SNOW MAKING BEELINE FOR NORTH CENTRAL
WI THIS MORNING WITH RAP BRINGING IT INTO CWA AROUND 6AM.
TEMPERATURE PROFILES SUGGEST MOSTLY SNOW OVER NORTHERN WI THROUGH
18Z...THEN START TO MIX...LIMITING SNOW TOTALS. STILL LOOKING FOR
5 TO 7 INCHES WESTERN AREAS OF VILAS...SO WILL KEEP WARNING AS IS. NO
CHANGES PLANNED FOR CURRENT HEADLINES. TO THE SOUTH...INCREASING
DEW POINTS OVER FRESH SNOW FROM PREVIOUS EVENING TO LEAD TO DENSE
FOG FORMATION...MAINLY EAST CENTRAL. MODELS A BIT FAST BRINGING
MOISTURE NORTH...SO PUSHED BACK TIMING IN GRIDS. WILL PLAY WATCH
AND SEE A BIT LONGER BEFORE ISSUING ANY HEADLINE GIVEN NUMBER OF
HEADLINES OUT RIGHT NOW.
STRONG COLD FRONT TO MOVE THROUGH TONIGHT...WITH WED MIN/THU MAX
AROUND 12Z THU. USED NON DIURNAL TREND FOR TEMPS FALLING THROUGH
THE DAY. APPARENT TEMPS ONLY IN SINGLE DIGITS ABOVE OR BELOW ZERO
FOR MUCH OF THU. BACKED OFF A BIT ON POPS FOR LAKE EFFECT SNOWS
FAR NORTH THU WITH WINDS TOO WESTERLY IN DIRECTION.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY
ISSUED AT 427 AM CST WED DEC 4 2013
MDLS CONT TO ADVERTISE AN AMPLIFIED MEAN FLOW THAT CONSISTED OF AN
ALASKA UPR RDG...A DEEP POSITIVE-TILTED LONGWAVE TROF FROM NRN
CANADA TO THE SW CONUS AND UPR RIDGING FROM FLORIDA INTO THE WRN
ATLANTIC. THIS PATTERN TO HOLD STEADY THRU THE UPCOMING WEEKEND
BEFORE THE ALASKA RDG BREAKS DOWN AND THE UPR TROF SHIFTS INTO THE
CNTRL CONUS BY THE END OF THE FCST PERIOD. A DRY AND VERY COLD AIR
MASS TO DEVELOP OVER NE WI THRU SAT NGT BEFORE THE NEXT SYSTEM IN
THE SW FLOW ALOFT ARRIVES LATE SUNDAY INTO MON. ANOTHER SURGE OF
ARCTIC AIR TO THEN OVERSPREAD THE REGION FOR THE MIDDLE OF NEXT
WEEK WITH TEMPS 20 TO 30 DEGS BELOW NORMAL.
LARGE ARCTIC HI PRES TO EXTEND FROM BRITISH COLUMBIA SEWD INTO THE
NRN/CNTRL PLAINS THU NGT WITH AN EWD EXTENT REACHING INTO THE
GREAT LAKES. THIS WOULD BRING PARTLY CLOUDY SKIES AND UNSEASONABLY
COLD CONDITIONS TO NE WI WITH TEMPS DROPPING BELOW ZERO OVER NRN/
PARTS OF CNTRL WI...WHILE LAKESHORE AREAS DIP INTO THE UPR SINGLE
DIGITS. ADD IN A WEST WIND AT 10 TO 15 MPH AND WE ARE LOOKING AT
WIND CHILL VALUES RANGING FROM 5 BELOW TO 20 BELOW ZERO BY
DAYBREAK. WL NEED TO WATCH N-CNTRL WI FOR A POSSIBLE WIND CHILL
ADVY IF WINDS CAN REMAIN STRONG ENUF.
QUIET AND VERY COLD CONDITIONS CONT THRU FRI AS THE ARCTIC HI TO
DOMINATE THE MIDDLE OF THE COUNTRY. THIS SFC HI WL KEEP A SYSTEM
MOVING FROM THE DEEP SOUTH TO THE MID-ATLANTIC STATES ADN NOT HAVE
ANY IMPACT ON OUR WEATHER. MAX TEMPS WL NOT GET OUT OF THE SINGLE
DIGITS OVER N-CNTRL WI...WITH TEENS EXPECTED ELSEWHERE. THIS WOULD
BE ABOUT 15 DEGS BELOW NORMAL.
THE ERN FLANK OF THE ARCTIC HI EDGES INTO THE WRN GREAT LAKES
REGION FRI NGT WITH A SLIGHT DIMINISH IN WIND SPEEDS. 8H TEMPS TO
HOVER IN THE -18 TO -20C RANGE AND WITH SKY CONDITIONS OF MOSTLY
CLEAR TO PARTLY CLOUDY...TEMPS WL BE EVEN COLDER THAN THU NGT WITH
READINGS FLIRTING WITH DOUBLE DIGITS BELOW ZERO IN THE NORTH...NEAR
ZERO AROUND THE FOX VALLEY AND AROUND 5 ABOVE ZERO NEAR LAKE MI. WE
COULD AGAIN BE LOOKING AT POSSIBLE WIND CHILL ADVYS ACROSS PARTS OF
NE WI AS VALUES FALL BELOW THE -20 DEG THRESHOLD. THE ARCTIC HI IS
FCST TO STRETCH FROM THE NRN HI PLAINS THRU THE GREAT LAKES ON
SAT...THEREBY PROVIDING FOR ANOTHER MOSTLY SUNNY TO PARTLY CLOUDY
DAY WITH TEMPS WELL BELOW NORMAL. IN FACT...MAX TEMPS WL NOT GET
OUT OF THE SINGLE DIGITS OVER NRN AND CNTRL WI AND ONLY IN THE 10
TO 15 DEG RANGE FOR E-CNTRL WI. THESE VALUES WOULD BE AROUND 20
DEGS BELOW NORMAL.
ATTENTION THEN TURNS TOWARD THE CNTRL CONUS LATE IN THE WEEKEND
WHERE A SYSTEM IS PROGGED TO EJECT NEWD OUT OF THE MAIN LONGWAVE
TROF. CLOUDS TO ALREADY BEGIN TO INCREASE SAT NGT...BUT QUESTIONS
REMAIN AS TO HOW FAST MOISTURE WL BE ABLE TO OVERSPREAD WI WITH
THE INITIAL DRY AIR MASS IN PLACE. EVEN WITH A STEADY INCREASE IN
ISEN LIFT THRU THE DAY...BELIEVE IT WL TAKE MOST OF SUNDAY JUST TO
SATURATE...THUS HAVE KEPT POPS ON THE LOW SIDE WITH A SLIGHT UPTICK
IN TEMPS AS 8H TEMPS `WARM` TO AROUND -14C.
AS ONE WOULD EXPECT THIS FAR OUT...THE MDLS ARE TRYING TO ZERO IN
ON THE TRACK OF THE STRENGTHENING AREA OF LOW PRES WHICH WL LIFT
NE TOWARD/INTO THE GREAT LAKES SUNDAY NGT. THE EXACT TRACK WL BE
CRUCIAL WHETHER NE WI SEES JUST LIGHT SNOW OR AN APPRECIABLE
ACCUMULATION WARRANTING A HEADLINE. HAVE RAISED POPS INTO THE HI
CHC CATEGORY FOR CNTRL WI AND LIKELY FOR ERN WI BASED ON THE MDLS
MOVING THE SFC LOW TOWARD ERN SECTIONS OF THE GREAT LAKES. WL NEED
TO WATCH THIS SYSTEM IN THE COMING DAYS AS ANY CHANGE IN STORM
TRACK WOULD AFFECT ACCUMULATION NUMBERS. THE SNOW SHOULD END MON
MORNING AS THE SFC LOW QUICKLY LIFTS NE INTO SE CANADA. ANY
ADDITIONAL ACCUMULATIONS APPEAR TO BE MINOR AT THIS POINT. THE
OTHER STORY FOR MON WL BE THE ONSET OF THE NEXT ARCTIC SURGE AS 8H
TEMPS CRASH THRU THE DAY. TEMPS MAY EASILY BE STEADY OR SLOWLY
FALL WITH LATE DAY TEMPS ALREADY DOWN INTO THE SINGLE DIGITS AND
TEENS.
THE COLDER AIR OF THE WINTER SEASON TO THEN SWEEP ACROSS THE GREAT
LAKES REGION MON NGT INTO TUE WITH 8H TEMPS PLUMMETING TO AS LOW
AS -26C. TOO MUCH OF A WESTERLY COMPONENT TO THE WIND TO BRING
LAKE EFFECT SNOWS INTO NRN WI...THUS AT LEAST A DRY FCST IS
ANTICIPATED. EXACTLY HOW COLD WE GET WL BE DETERMINED BY THE
EXTENT OF THE SNOW COVER OVER THE FCST AREA. BY TUE MORNING...SUB-
ZERO TEMPS COULD COVER ALL BUT THE LAKESHORE AREAS WITH MAX TEMPS
ON TUE PERHAPS NOT GETTING ABOVE ZERO OVER N-CNTRL WI.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 544 AM CST WED DEC 4 2013
GENERALLY POOR FLIGHT CONDITIONS EXPECTED INTO THIS EVENING WITH
SNOW OR A WINTRY MIX NORTH AND FOG SOUTH. LIGHT FREEZING PCPN WILL
AFFECT CENTRAL TAF SITES THROUGH THE MORNING...THOUGH SURFACE
TEMPERATURES ARE EXPECTED TO CLIMB TO ABOVE FREEZING MID MORNING.
BRISK WESTERLY WINDS EXPECTED BEHIND SYSTEM THIS EVENING AND
OVERNIGHT...WITH VISBYS/CIGS IMPROVING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ018>021-030-
031-035>037-045.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
WIZ010>012.
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR WIZ005.
&&
$$
UPDATE.........RDM
SHORT TERM.....TE
LONG TERM......KALLAS
AVIATION.......TE
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
615 AM CST WED DEC 4 2013
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND THURSDAY
ISSUED AT 427 AM CST WED DEC 4 2013
FOCUS IS ON PCPN TYPES AND AMOUNTS TODAY...THEN FALLING
TEMPERATURES TONIGHT AND THU.
MODELS ARE IN BETTER AGREEMENT TONIGHT...USED A BLEND...LEANING A
BIT MORE ON ECMWF FOR THIS PERIOD. MADE EARLIER CHANGE TO
HEADLINES WITH ISSUANCE OF WINTER WEATHER ADVISORY FOR CENTRAL WI
AS TEMPERATURES NOT MOVING ABOVE FREEZING...ACTUALLY DROPPED. LIGHT
PCPN CONTINUES TO LIFT NORTH INTO CWA. CALLS TO PORTAGE AND WOOD
COUNTIES INDICATED ICING ISSUES ON ROADS. LOOKING FOR
TEMPERATURES TO MOVE ABOVE FREEZING MID MORNING.
RADAR MOSAIC SHOWING AREA OF SNOW MAKING BEELINE FOR NORTH CENTRAL
WI THIS MORNING WITH RAP BRINGING IT INTO CWA AROUND 6AM.
TEMPERATURE PROFILES SUGGEST MOSTLY SNOW OVER NORTHERN WI THROUGH
18Z...THEN START TO MIX...LIMITING SNOW TOTALS. STILL LOOKING FOR
5 TO 7 INCHES WESTERN AREAS OF VILAS...SO WILL KEEP WARNING AS IS. NO
CHANGES PLANNED FOR CURRENT HEADLINES. TO THE SOUTH...INCREASING
DEW POINTS OVER FRESH SNOW FROM PREVIOUS EVENING TO LEAD TO DENSE
FOG FORMATION...MAINLY EAST CENTRAL. MODELS A BIT FAST BRINGING
MOISTURE NORTH...SO PUSHED BACK TIMING IN GRIDS. WILL PLAY WATCH
AND SEE A BIT LONGER BEFORE ISSUING ANY HEADLINE GIVEN NUMBER OF
HEADLINES OUT RIGHT NOW.
STRONG COLD FRONT TO MOVE THROUGH TONIGHT...WITH WED MIN/THU MAX
AROUND 12Z THU. USED NON DIURNAL TREND FOR TEMPS FALLING THROUGH
THE DAY. APPARENT TEMPS ONLY IN SINGLE DIGITS ABOVE OR BELOW ZERO
FOR MUCH OF THU. BACKED OFF A BIT ON POPS FOR LAKE EFFECT SNOWS
FAR NORTH THU WITH WINDS TOO WESTERLY IN DIRECTION.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY
ISSUED AT 427 AM CST WED DEC 4 2013
MDLS CONT TO ADVERTISE AN AMPLIFIED MEAN FLOW THAT CONSISTED OF AN
ALASKA UPR RDG...A DEEP POSITIVE-TILTED LONGWAVE TROF FROM NRN
CANADA TO THE SW CONUS AND UPR RIDGING FROM FLORIDA INTO THE WRN
ATLANTIC. THIS PATTERN TO HOLD STEADY THRU THE UPCOMING WEEKEND
BEFORE THE ALASKA RDG BREAKS DOWN AND THE UPR TROF SHIFTS INTO THE
CNTRL CONUS BY THE END OF THE FCST PERIOD. A DRY AND VERY COLD AIR
MASS TO DEVELOP OVER NE WI THRU SAT NGT BEFORE THE NEXT SYSTEM IN
THE SW FLOW ALOFT ARRIVES LATE SUNDAY INTO MON. ANOTHER SURGE OF
ARCTIC AIR TO THEN OVERSPREAD THE REGION FOR THE MIDDLE OF NEXT
WEEK WITH TEMPS 20 TO 30 DEGS BELOW NORMAL.
LARGE ARCTIC HI PRES TO EXTEND FROM BRITISH COLUMBIA SEWD INTO THE
NRN/CNTRL PLAINS THU NGT WITH AN EWD EXTENT REACHING INTO THE
GREAT LAKES. THIS WOULD BRING PARTLY CLOUDY SKIES AND UNSEASONABLY
COLD CONDITIONS TO NE WI WITH TEMPS DROPPING BELOW ZERO OVER NRN/
PARTS OF CNTRL WI...WHILE LAKESHORE AREAS DIP INTO THE UPR SINGLE
DIGITS. ADD IN A WEST WIND AT 10 TO 15 MPH AND WE ARE LOOKING AT
WIND CHILL VALUES RANGING FROM 5 BELOW TO 20 BELOW ZERO BY
DAYBREAK. WL NEED TO WATCH N-CNTRL WI FOR A POSSIBLE WIND CHILL
ADVY IF WINDS CAN REMAIN STRONG ENUF.
QUIET AND VERY COLD CONDITIONS CONT THRU FRI AS THE ARCTIC HI TO
DOMINATE THE MIDDLE OF THE COUNTRY. THIS SFC HI WL KEEP A SYSTEM
MOVING FROM THE DEEP SOUTH TO THE MID-ATLANTIC STATES ADN NOT HAVE
ANY IMPACT ON OUR WEATHER. MAX TEMPS WL NOT GET OUT OF THE SINGLE
DIGITS OVER N-CNTRL WI...WITH TEENS EXPECTED ELSEWHERE. THIS WOULD
BE ABOUT 15 DEGS BELOW NORMAL.
THE ERN FLANK OF THE ARCTIC HI EDGES INTO THE WRN GREAT LAKES
REGION FRI NGT WITH A SLIGHT DIMINISH IN WIND SPEEDS. 8H TEMPS TO
HOVER IN THE -18 TO -20C RANGE AND WITH SKY CONDITIONS OF MOSTLY
CLEAR TO PARTLY CLOUDY...TEMPS WL BE EVEN COLDER THAN THU NGT WITH
READINGS FLIRTING WITH DOUBLE DIGITS BELOW ZERO IN THE NORTH...NEAR
ZERO AROUND THE FOX VALLEY AND AROUND 5 ABOVE ZERO NEAR LAKE MI. WE
COULD AGAIN BE LOOKING AT POSSIBLE WIND CHILL ADVYS ACROSS PARTS OF
NE WI AS VALUES FALL BELOW THE -20 DEG THRESHOLD. THE ARCTIC HI IS
FCST TO STRETCH FROM THE NRN HI PLAINS THRU THE GREAT LAKES ON
SAT...THEREBY PROVIDING FOR ANOTHER MOSTLY SUNNY TO PARTLY CLOUDY
DAY WITH TEMPS WELL BELOW NORMAL. IN FACT...MAX TEMPS WL NOT GET
OUT OF THE SINGLE DIGITS OVER NRN AND CNTRL WI AND ONLY IN THE 10
TO 15 DEG RANGE FOR E-CNTRL WI. THESE VALUES WOULD BE AROUND 20
DEGS BELOW NORMAL.
ATTENTION THEN TURNS TOWARD THE CNTRL CONUS LATE IN THE WEEKEND
WHERE A SYSTEM IS PROGGED TO EJECT NEWD OUT OF THE MAIN LONGWAVE
TROF. CLOUDS TO ALREADY BEGIN TO INCREASE SAT NGT...BUT QUESTIONS
REMAIN AS TO HOW FAST MOISTURE WL BE ABLE TO OVERSPREAD WI WITH
THE INITIAL DRY AIR MASS IN PLACE. EVEN WITH A STEADY INCREASE IN
ISEN LIFT THRU THE DAY...BELIEVE IT WL TAKE MOST OF SUNDAY JUST TO
SATURATE...THUS HAVE KEPT POPS ON THE LOW SIDE WITH A SLIGHT UPTICK
IN TEMPS AS 8H TEMPS `WARM` TO AROUND -14C.
AS ONE WOULD EXPECT THIS FAR OUT...THE MDLS ARE TRYING TO ZERO IN
ON THE TRACK OF THE STRENGTHENING AREA OF LOW PRES WHICH WL LIFT
NE TOWARD/INTO THE GREAT LAKES SUNDAY NGT. THE EXACT TRACK WL BE
CRUCIAL WHETHER NE WI SEES JUST LIGHT SNOW OR AN APPRECIABLE
ACCUMULATION WARRANTING A HEADLINE. HAVE RAISED POPS INTO THE HI
CHC CATEGORY FOR CNTRL WI AND LIKELY FOR ERN WI BASED ON THE MDLS
MOVING THE SFC LOW TOWARD ERN SECTIONS OF THE GREAT LAKES. WL NEED
TO WATCH THIS SYSTEM IN THE COMING DAYS AS ANY CHANGE IN STORM
TRACK WOULD AFFECT ACCUMULATION NUMBERS. THE SNOW SHOULD END MON
MORNING AS THE SFC LOW QUICKLY LIFTS NE INTO SE CANADA. ANY
ADDITIONAL ACCUMULATIONS APPEAR TO BE MINOR AT THIS POINT. THE
OTHER STORY FOR MON WL BE THE ONSET OF THE NEXT ARCTIC SURGE AS 8H
TEMPS CRASH THRU THE DAY. TEMPS MAY EASILY BE STEADY OR SLOWLY
FALL WITH LATE DAY TEMPS ALREADY DOWN INTO THE SINGLE DIGITS AND
TEENS.
THE COLDER AIR OF THE WINTER SEASON TO THEN SWEEP ACROSS THE GREAT
LAKES REGION MON NGT INTO TUE WITH 8H TEMPS PLUMMETING TO AS LOW
AS -26C. TOO MUCH OF A WESTERLY COMPONENT TO THE WIND TO BRING
LAKE EFFECT SNOWS INTO NRN WI...THUS AT LEAST A DRY FCST IS
ANTICIPATED. EXACTLY HOW COLD WE GET WL BE DETERMINED BY THE
EXTENT OF THE SNOW COVER OVER THE FCST AREA. BY TUE MORNING...SUB-
ZERO TEMPS COULD COVER ALL BUT THE LAKESHORE AREAS WITH MAX TEMPS
ON TUE PERHAPS NOT GETTING ABOVE ZERO OVER N-CNTRL WI.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 544 AM CST WED DEC 4 2013
GENERALLY POOR FLIGHT CONDITIONS EXPECTED INTO THIS EVENING WITH
SNOW OR A WINTRY MIX NORTH AND FOG SOUTH. LIGHT FREEZING PCPN WILL
AFFECT CENTRAL TAF SITES THROUGH THE MORNING...THOUGH SURFACE
TEMPERATURES ARE EXPECTED TO CLIMB TO ABOVE FREEZING MID MORNING.
BRISK WESTERLY WINDS EXPECTED BEHIND SYSTEM THIS EVENING AND
OVERNIGHT...WITH VISBYS/CIGS IMPROVING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
WIZ010>012.
WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ020-
021-030-031-035>037-045.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ018-019.
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR WIZ005.
&&
$$
SHORT TERM.....TE
LONG TERM......KALLAS
AVIATION.......TE
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND THURSDAY
ISSUED AT 427 AM CST WED DEC 4 2013
FOCUS IS ON PCPN TYPES AND AMOUNTS TODAY...THEN FALLING
TEMPERATURES TONIGHT AND THU.
MODELS ARE IN BETTER AGREEMENT TONIGHT...USED A BLEND...LEANING A
BIT MORE ON ECMWF FOR THIS PERIOD. MADE EARLIER CHANGE TO
HEADLINES WITH ISSUANCE OF WINTER WEATHER ADVISORY FOR CENTRAL WI
AS TEMPERATURES NOT MOVING ABOVE FREEZING...ACTUALLY DROPPED. LIGHT
PCPN CONTINUES TO LIFT NORTH INTO CWA. CALLS TO PORTAGE AND WOOD
COUNTIES INDICATED ICING ISSUES ON ROADS. LOOKING FOR
TEMPERATURES TO MOVE ABOVE FREEZING MID MORNING.
RADAR MOSAIC SHOWING AREA OF SNOW MAKING BEELINE FOR NORTH CENTRAL
WI THIS MORNING WITH RAP BRINGING IT INTO CWA AROUND 6AM.
TEMPERATURE PROFILES SUGGEST MOSTLY SNOW OVER NORTHERN WI THROUGH
18Z...THEN START TO MIX...LIMITING SNOW TOTALS. STILL LOOKING FOR
5 TO 7 INCHES WESTERN AREAS OF VILAS...SO WILL KEEP WARNING AS IS. NO
CHANGES PLANNED FOR CURRENT HEADLINES. TO THE SOUTH...INCREASING
DEW POINTS OVER FRESH SNOW FROM PREVIOUS EVENING TO LEAD TO DENSE
FOG FORMATION...MAINLY EAST CENTRAL. MODELS A BIT FAST BRINGING
MOISTURE NORTH...SO PUSHED BACK TIMING IN GRIDS. WILL PLAY WATCH
AND SEE A BIT LONGER BEFORE ISSUING ANY HEADLINE GIVEN NUMBER OF
HEADLINES OUT RIGHT NOW.
STRONG COLD FRONT TO MOVE THROUGH TONIGHT...WITH WED MIN/THU MAX
AROUND 12Z THU. USED NON DIURNAL TREND FOR TEMPS FALLING THROUGH
THE DAY. APPARENT TEMPS ONLY IN SINGLE DIGITS ABOVE OR BELOW ZERO
FOR MUCH OF THU. BACKED OFF A BIT ON POPS FOR LAKE EFFECT SNOWS
FAR NORTH THU WITH WINDS TOO WESTERLY IN DIRECTION.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY
ISSUED AT 427 AM CST WED DEC 4 2013
MDLS CONT TO ADVERTISE AN AMPLIFIED MEAN FLOW THAT CONSISTED OF AN
ALASKA UPR RDG...A DEEP POSITIVE-TILTED LONGWAVE TROF FROM NRN
CANADA TO THE SW CONUS AND UPR RIDGING FROM FLORIDA INTO THE WRN
ATLANTIC. THIS PATTERN TO HOLD STEADY THRU THE UPCOMING WEEKEND
BEFORE THE ALASKA RDG BREAKS DOWN AND THE UPR TROF SHIFTS INTO THE
CNTRL CONUS BY THE END OF THE FCST PERIOD. A DRY AND VERY COLD AIR
MASS TO DEVELOP OVER NE WI THRU SAT NGT BEFORE THE NEXT SYSTEM IN
THE SW FLOW ALOFT ARRIVES LATE SUNDAY INTO MON. ANOTHER SURGE OF
ARCTIC AIR TO THEN OVERSPREAD THE REGION FOR THE MIDDLE OF NEXT
WEEK WITH TEMPS 20 TO 30 DEGS BELOW NORMAL.
LARGE ARCTIC HI PRES TO EXTEND FROM BRITISH COLUMBIA SEWD INTO THE
NRN/CNTRL PLAINS THU NGT WITH AN EWD EXTENT REACHING INTO THE
GREAT LAKES. THIS WOULD BRING PARTLY CLOUDY SKIES AND UNSEASONABLY
COLD CONDITIONS TO NE WI WITH TEMPS DROPPING BELOW ZERO OVER NRN/
PARTS OF CNTRL WI...WHILE LAKESHORE AREAS DIP INTO THE UPR SINGLE
DIGITS. ADD IN A WEST WIND AT 10 TO 15 MPH AND WE ARE LOOKING AT
WIND CHILL VALUES RANGING FROM 5 BELOW TO 20 BELOW ZERO BY
DAYBREAK. WL NEED TO WATCH N-CNTRL WI FOR A POSSIBLE WIND CHILL
ADVY IF WINDS CAN REMAIN STRONG ENUF.
QUIET AND VERY COLD CONDITIONS CONT THRU FRI AS THE ARCTIC HI TO
DOMINATE THE MIDDLE OF THE COUNTRY. THIS SFC HI WL KEEP A SYSTEM
MOVING FROM THE DEEP SOUTH TO THE MID-ATLANTIC STATES ADN NOT HAVE
ANY IMPACT ON OUR WEATHER. MAX TEMPS WL NOT GET OUT OF THE SINGLE
DIGITS OVER N-CNTRL WI...WITH TEENS EXPECTED ELSEWHERE. THIS WOULD
BE ABOUT 15 DEGS BELOW NORMAL.
THE ERN FLANK OF THE ARCTIC HI EDGES INTO THE WRN GREAT LAKES
REGION FRI NGT WITH A SLIGHT DIMINISH IN WIND SPEEDS. 8H TEMPS TO
HOVER IN THE -18 TO -20C RANGE AND WITH SKY CONDITIONS OF MOSTLY
CLEAR TO PARTLY CLOUDY...TEMPS WL BE EVEN COLDER THAN THU NGT WITH
READINGS FLIRTING WITH DOUBLE DIGITS BELOW ZERO IN THE NORTH...NEAR
ZERO AROUND THE FOX VALLEY AND AROUND 5 ABOVE ZERO NEAR LAKE MI. WE
COULD AGAIN BE LOOKING AT POSSIBLE WIND CHILL ADVYS ACROSS PARTS OF
NE WI AS VALUES FALL BELOW THE -20 DEG THRESHOLD. THE ARCTIC HI IS
FCST TO STRETCH FROM THE NRN HI PLAINS THRU THE GREAT LAKES ON
SAT...THEREBY PROVIDING FOR ANOTHER MOSTLY SUNNY TO PARTLY CLOUDY
DAY WITH TEMPS WELL BELOW NORMAL. IN FACT...MAX TEMPS WL NOT GET
OUT OF THE SINGLE DIGITS OVER NRN AND CNTRL WI AND ONLY IN THE 10
TO 15 DEG RANGE FOR E-CNTRL WI. THESE VALUES WOULD BE AROUND 20
DEGS BELOW NORMAL.
ATTENTION THEN TURNS TOWARD THE CNTRL CONUS LATE IN THE WEEKEND
WHERE A SYSTEM IS PROGGED TO EJECT NEWD OUT OF THE MAIN LONGWAVE
TROF. CLOUDS TO ALREADY BEGIN TO INCREASE SAT NGT...BUT QUESTIONS
REMAIN AS TO HOW FAST MOISTURE WL BE ABLE TO OVERSPREAD WI WITH
THE INITIAL DRY AIR MASS IN PLACE. EVEN WITH A STEADY INCREASE IN
ISEN LIFT THRU THE DAY...BELIEVE IT WL TAKE MOST OF SUNDAY JUST TO
SATURATE...THUS HAVE KEPT POPS ON THE LOW SIDE WITH A SLIGHT UPTICK
IN TEMPS AS 8H TEMPS `WARM` TO AROUND -14C.
AS ONE WOULD EXPECT THIS FAR OUT...THE MDLS ARE TRYING TO ZERO IN
ON THE TRACK OF THE STRENGTHENING AREA OF LOW PRES WHICH WL LIFT
NE TOWARD/INTO THE GREAT LAKES SUNDAY NGT. THE EXACT TRACK WL BE
CRUCIAL WHETHER NE WI SEES JUST LIGHT SNOW OR AN APPRECIABLE
ACCUMULATION WARRANTING A HEADLINE. HAVE RAISED POPS INTO THE HI
CHC CATEGORY FOR CNTRL WI AND LIKELY FOR ERN WI BASED ON THE MDLS
MOVING THE SFC LOW TOWARD ERN SECTIONS OF THE GREAT LAKES. WL NEED
TO WATCH THIS SYSTEM IN THE COMING DAYS AS ANY CHANGE IN STORM
TRACK WOULD AFFECT ACCUMULATION NUMBERS. THE SNOW SHOULD END MON
MORNING AS THE SFC LOW QUICKLY LIFTS NE INTO SE CANADA. ANY
ADDITIONAL ACCUMULATIONS APPEAR TO BE MINOR AT THIS POINT. THE
OTHER STORY FOR MON WL BE THE ONSET OF THE NEXT ARCTIC SURGE AS 8H
TEMPS CRASH THRU THE DAY. TEMPS MAY EASILY BE STEADY OR SLOWLY
FALL WITH LATE DAY TEMPS ALREADY DOWN INTO THE SINGLE DIGITS AND
TEENS.
THE COLDER AIR OF THE WINTER SEASON TO THEN SWEEP ACROSS THE GREAT
LAKES REGION MON NGT INTO TUE WITH 8H TEMPS PLUMMETING TO AS LOW
AS -26C. TOO MUCH OF A WESTERLY COMPONENT TO THE WIND TO BRING
LAKE EFFECT SNOWS INTO NRN WI...THUS AT LEAST A DRY FCST IS
ANTICIPATED. EXACTLY HOW COLD WE GET WL BE DETERMINED BY THE
EXTENT OF THE SNOW COVER OVER THE FCST AREA. BY TUE MORNING...SUB-
ZERO TEMPS COULD COVER ALL BUT THE LAKESHORE AREAS WITH MAX TEMPS
ON TUE PERHAPS NOT GETTING ABOVE ZERO OVER N-CNTRL WI.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1040 PM CST TUE DEC 3 2013
GENERALLY POOR FLIGHT CONDITIONS WL PERSIST WITH MOIST ELY FLOW.
CONDITIONS IN MOST AREAS WON/T IMPROVE SIGNIFICANTLY UNTIL
TOMORROW EVENING...WHEN SYSTEM BEGINS TO LIFT OFF TO THE NE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR
WIZ010>012.
WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ020-
021-030-031-035>037-045.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ018-019.
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR WIZ005.
&&
$$
SHORT TERM.....TE
LONG TERM......KALLAS
AVIATION.......SKOWRONSKI
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1144 PM EST THU DEC 5 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 1258 PM EST THU DEC 5 2013
AN ACTIVE WEATHER PATTERN IS EXPECTED THE NEXT 24 HOURS AS WINTRY
WEATHER RETURNS TO CENTRAL INDIANA. A COLD FRONT HAS PUSHED
SOUTHEAST OF CENTRAL INDIANA...ALLOWING MUCH COLDER AIR TO PUSH IN
TO THE AREA. A FLOW OF MOIST AIR ALOFT ALONG WITH SEVERAL UPPER
LEVEL WEATHER DISTURBANCES ARE EXPECTED TO PUSH IN TO
CENTRAL INDIANA TONIGHT AND AGAIN ON FRIDAY. THIS WILL RESULT IN
ACCUMULATING SNOW TONIGHT AND FRIDAY FOR MOST OF CENTRAL
INDIANA...AND THE FIRST REAL BIG SNOW OF THE SEASON.
HIGH PRESSURE IS EXPECTED TO BUILD ACROSS THE AREA FRIDAY
NIGHT...ENDING THE SNOW. HOWEVER VERY COLD...ARCTIC AIR WILL ARRIVE
IN INDIANA...WITH TEMPERATURES WELL BELOW NORMAL THOUGH THE WEEKEND.
ANOTHER PASSING STORM SYSTEM MAY BRING SOME LIGHT SNOW OR FREEZING
PRECIPITATION TO AREA ON SUNDAY THROUGH MONDAY. YET ANOTHER SHOT
OF ARCTIC AIR IS THEN EXPECTED TO ARRIVE ON FOR THE MIDDLE OF NEXT
WEEK AND HIGH TEMPERATURES WILL ONLY BE IN THE TEENS.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 951 PM EST THU DEC 5 2013
NAM12 AND RUC13 MODEL SOUNDINGS AND OBSERVATIONAL TRENDS SUGGEST
PRECIPITATION TYPE WILL MAINLY BE SNOW THE REST OF THE NIGHT WITH
THE EXCEPTION OF THE FAR SOUTH...WHERE SOME SLEET IS POSSIBLE
THROUGH MIDNIGHT. LOOKING AT RAPID REFRESH REFLECTIVITY PROGS AND
WITH SHARP DEEP MOISTURE GRADIENT...SOME CONCERN NORTHWEST COUNTIES
WILL NOT SEE MUCH ACCUMULATION TONIGHT...BUT HATE TO PULL POPS AND
ACCUMULATION TOO SOON...SO FOR NOW WILL STICK WITH IT. UPDATED
GRIDS...HAZARDOUS WEATHER OUTLOOK AND WEATHER STORY WITH NEW WEB
STORM BRIEFING TO COME.
PREVIOUS DISCUSSION FOLLOWS...
RADAR THIS AFTERNOON SHOWS A SURGE OF MOISTURE OVER SOUTHERN
ILLINOIS STREAMING NORTHEAST TOWARD CENTRAL INDIANA. SURFACE
ANALYSIS EARLY THIS AFTERNOON SHOWS COLD HIGH PRESSURE IN PLACE
ACROSS THE CENTRAL PLAINS AND A COLD FRONT EAST OF INDIANA...OVER
CENTRAL OHIO...EASTERN KENTUCKY AND CENTRAL TENNESSEE. COLD WEST
TO NORTHWEST SURFACE FLOW WAS IN PLACE ACROSS CENTRAL INDIANA.
SURFACE TEMPS WERE FALLING THIS AFTERNOON ACROSS THE NORTHWEST
PARTS OF THE STATE AND BARELY RISING ACROSS SOUTH. THE WATER VAPOR
IMAGERY IS IMPORTANT TODAY. IT SHOWS A PLUME OF MOISTURE STREAMING
ACROSS MEXICO INTO THE AMERICAN SOUTHWEST AND THEN NORTHEAST INTO
THE GREAT LAKES AND OHIO VALLEY. THIS STREAM OF MOISTURE WILL BE
OUR SOURCE FOR PRECIP OVER THE NEXT 24-36 HOURS.
FORECAST SOUNDINGS ACROSS THE AREA LEAN TOWARD A FREEZING RAIN
PRECIP TYPE LATE THIS AFTERNOON AND THIS EVENING ACROSS SOUTHERN
PARTS OF CENTRAL INDIANA. PRECIPITABLE WATER VALUES AROUND 0.8
INDICATE PLENTY OF MOISTURE AVAILABLE FOR THIS SYSTEM. COLDER AIR
IS EXPECTED TO ARRIVE ACROSS THE ENTIRE FORECAST AREA AFTER 06Z AS
ALL FORECAST SOUNDINGS FALL BELOW FREEZING...CHANGING THE PRECIP
TYPE TO ALL SNOW REGION WIDE.
THUS HAVE TRENDED FORECASTS TOWARD 100 POPS...WITH BEST CHANCES
FOR FREEZING PRECIP ACROSS SOUTHERN PARTS OF THE FORECAST AREA
THIS EVENING. ALSO GIVEN THE EXPECTED PATH OF THE BAND OF
MOISTURE...SOUTHERN INDIANA IS IN THE MOST FAVORABLE POSITION FOR
HEAVIER SNOW AMOUNTS. AS FOR TEMPS...GIVEN THE COLD AIR ADVECTION
BUT EXPECTED PRECIPITATION...HAVE TRENDED LOWS AT OR ABOVE MAVMOS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
ISSUED AT 1258 PM EST THU DEC 5 2013
SNOW IS EXPECTED ON FRIDAY. FORECAST SOUNDINGS AND TIME HEIGHT
SECTIONS CONTINUE TO SUGGEST A SATURATED COLUMN THROUGH THE DAY
WITH SOUNDINGS ENTIRELY BELOW FREEZING. FLOW ALOFT CONTINUES TO
SUGGEST THE MOIST SOUTHERN JET OF MOISTURE STREAMING IN TO THE
OHIO VALLEY. EMBEDDED SHORT WAVE ARE EXPECTED TO PROVIDE MORE
FORCING FOR ONGOING SNOW. TIME HEIGHT SECTIONS SHOW ANOTHER ROUND
OF GOOD VV DURING THE AFTERNOON HOURS. PRECIPITABLE WATER VIA
FORECAST SOUNDINGS SHOW A CONTINUOUS STREAM OF MOISTURE ACROSS THE
AREA WITH VALUES AROUND 0.60-0.80 FROM 12Z THROUGH 18Z AND AFTER
BEFORE TRAILING OFF AFTER 00Z SAT. THUS PLENTY OF MOISTURE APPEARS
AVAILABLE.
FRONTOGENESIS FORCING APPEARS VERY FAVORABLE FOR THIS
EVENT...AGAIN SHOWING A PERIOD STRONG FORCING MID DAY FRIDAY. THUS
WITH HIGH MOISTURE AND VERY GOOD FORCING EXPECT BANDS OF SNOW
ACROSS THE AREA ON FRIDAY. AGAIN...HEAVIEST AMOUNTS WILL BE ACROSS
THE SOUTHERN PARTS OF FORECAST AREA...WITH LIGHTER AMOUNTS NORTHWEST.
WITH ONGOING PRECIP EXPECTED ON FRIDAY HAVE TRENDED TEMPS COOLER
THAN MAV...STEADY IN THE UPPER 20S.
ON FRIDAY NIGHT...DEEP MOISTURE IS LOST IN THE FORECAST SOUNDINGS
AS BEST FORCING IS LOST AND THE SOUTHERN STREAM SHIFTS EAST. HIGH
PRESSURE OVER THE CENTRAL PLAINS CONTINUES TO BUILD ACROSS THE
REGION A COLD SURFACE RIDGE BUILDS ACROSS CENTRAL ILLINOIS AND
CENTRAL INDIANA. THUS WILL TREND TOWARD A BECOMING PARTLY CLOUDY
SKY. A FEW LINGERING SNOW SHOWERS OR FLURRIES WILL BE POSSIBLE
ACROSS THE EAST AS FRIDAY/S SYSTEM DEPARTS.
HIGH PRESSURE WILL PROVIDE COLD BUT DRY WEATHER FOR SATURDAY.
FORECAST SOUNDINGS REMAIN QUITE DRY. THUS WILL TREND TOWARD A
PARTLY CLOUDY SKY. AS FOR TEMPS DURING THIS PERIOD...GIVEN THE
EXPECTED FRESH SNOW AND COLD AIR IN PLACE WILL TREND HIGHS AND
LOWS COOLER THAN MAVMOS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 252 PM EST THU DEC 5 2013
MAIN ISSUE IN THE LONG TERM IS ANOTHER WINTER SYSTEM POSSIBLY
IMPACTING THE AREA EARLY SUNDAY INTO SUNDAY NIGHT. MODELS APPEAR
THEY MAY BE TRENDING SLIGHTLY COOLER MAINLY DURING THE DAY ON
SUNDAY. PRECIP MAY SNEAK INTO THE SOUTHERN FORECAST AREA AROUND
DAYBREAK SUNDAY IN THE FORM OF SNOW...WITH LIGHT SNOW POTENTIALLY
ACROSS MUCH OF THE AREA SUNDAY MORNING. PRECIP MAY TRANSITION TO A
MIX OF SLEET AND SNOW WITH SOME FREEZING RAIN POSSIBLE ACROSS THE
SOUTHWEST SUNDAY AFTERNOON. THIS MIX POTENTIAL WILL EXPAND A BIT
FURTHER NORTHWEST SUNDAY EVENING BEFORE COLD AIR AGAIN OVERTAKES THE
AREA AND MOST PRECIP LATE SUNDAY NIGHT CHANGES BACK TO SNOW...WITH
THE EXCEPTION OF A LIGHT MIX POSSIBLE IN THE EAST.
AMOUNTS WITH THIS SYSTEM...WHILE STILL QUITE UNCERTAIN BEING SO FAR
OUT...APPEAR VERY LIGHT ACROSS MOST OF THE FORECAST AREA. ACROSS THE
SOUTHEASTERN HALF OF THE AREA...FROM VINCENNES TO INDIANAPOLIS AND
MUNCIE SOUTHEASTWARD...1-3 INCHES OF SNOW/SLEET APPEAR POSSIBLE WITH
POTENTIAL FOR A FEW HUNDREDTHS OF FREEZING RAIN. SNOW/SLEET
ACCUMULATIONS OF UP TO 4 INCHES APPEAR POSSIBLE ACROSS THE FAR
SOUTHEASTERN FORECAST AREA...IN THE NORTH VERNON AREA.
ONCE THIS SYSTEM EXITS...DRY WEATHER WILL DOMINATE THE REMAINDER OF
THE FORECAST PERIOD...AND TEMPS WILL TURN SHARPLY COLDER. HIGHS MAY
NOT GET OUT OF THE TEENS AT TIMES NEXT WEEK. ALLBLEND HANDLED THE
OUTER PERIODS WELL AND FEW CHANGES WERE REQUIRED.
&&
.AVIATION /DISCUSSION FOR 060600Z TAF ISSUANCE/...
ISSUED AT 1135 PM EST THU DEC 5 2013
IFR AND LOWER CONDITIONS EXPECTED AT ALL BUT KLAF WITH LIGHT TO
MODERATE SNOW FALLING THROUGH THE OVERNIGHT AND THROUGH THE DAY
FRIDAY. VISIBILITIES IN THE SNOW ARE GENERALLY RUNNING 1 TO 2
MILES WITH SHORT BOUTS OF 1/4 TO 3/4SM WHEN A HEAVIER BAND
DEVELOPS. LOOKING AT UPSTREAM OBSERVATIONS AND FORECAST SOUNDINGS
LOOKS LIKE THE BEST SHOT FOR THIS TO HAPPEN AGAIN AT THE SITES WILL
BE IN THE 6 TO 9Z TIMEFRAME AT KHUF AND KIND AND A BIT LATER AT
KBMG SO WILL CONTINUE TO TEMPO IN THE LOWER CONDITIONS THEN. LIGHT TO
MODERATE SNOWFALL WILL CONTINUE THROUGH THE DAY FRIDAY WITH IFR
CONDITIONS EXPECTED. SNOW COULD OCCUR FOR A FEW HOURS AT KLAF FROM
LATE MORNING TO MID AFTERNOON BUT EXPECT MVFR THERE. CONDITIONS
SHOULD START TO IMPROVE BY 0Z SATURDAY AS THE WINTER SYSTEM MOVES
OUT OF THE AREA.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL MIDNIGHT EST FRIDAY NIGHT FOR INZ037-
039>042-044>049-051>057-060>065-067>072.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST FRIDAY NIGHT FOR
INZ021-028>031-035-036-038-043.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA/MK
SHORT TERM...PUMA
LONG TERM....NIELD
AVIATION...CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
310 AM CST FRI DEC 6 2013
.SYNOPSIS...
ISSUED AT 307 AM CST FRI DEC 6 2013
LATEST SURFACE ANALYSIS INDICATED A SURFACE RIDGE OF HIGH PRESSURE
BUILDING EAST SOUTHEASTWARD INTO IOWA AND ILLINOIS. A COLD FRONT
WAS DRAPED FROM THE SOUTHERN TIP OF TEXAS NORTHEAST TO NEW YORK.
MID AND HIGH LEVEL CLOUDINESS FROM THE NORTHWEST PERIPHERY OF THE
WINTER STORM SYSTEM TO THE SOUTH AND SOUTHEAST IS SEEN STREAMING
NORTHEAST ACROSS THE CWFA. NORTHWEST WINDS AT 8 TO 15 MPH WERE
OBSERVED AT 3AM...WITH A FEW GUSTS AROUND 20 MPH. TEMPERATURES
RANGE FROM 7 TO 17 DEGREES...WITH THE WARMER READINGS IN THE
SOUTHEAST...CLOSER TO THE SOUTHERN WINTER STORM.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 307 AM CST FRI DEC 6 2013
RELATIVELY QUIET AND COLD CONDITIONS WILL CHARACTERIZE THE WEATHER IN
THE SHORT TERM. ARCTIC HIGH PRESSURE WILL CONTINUE TO BUILD OVER
THE AREA OVER THE NEXT 24 HOURS. SOME MID AND HIGH LEVEL CLOUDINESS
WILL CONTINUE TO OVERSPREAD THE AREA FROM THE SOUTHWEST TODAY...WITH
CLEARING CONDITIONS TONIGHT. FLURRIES MAY BE POSSIBLE ACROSS THE
SOUTHEAST 1/4 OF THE CWFA...BUT OPTED TO LEAVE MENTION OUT OF GRIDS
AT THIS TIME. WINDS WILL REMAIN ON THE BLUSTERY SIDE THROUGH THE
MAJORITY OF THE PERIOD...DIMINISHING UNDER 10 MPH BY SATURDAY
MORNING. TEMPERATURES LOOK TO BE ON TRACK...WITH HIGHS TODAY
STRUGGLING TO REACH THE TEENS AND LOWER 20S. LOWERED MINS SAT
MORNING JUST A TAD WITH CLEAR SKIES AND LIGHTER WINDS...WITH MINS IN
THE MINUS 3 TO 8 ABOVE RANGE. WIND CHILLS THIS MORNING WILL SLIP
INTO THE LOWER SINGLE DIGITS ABOVE ZERO EAST NEAR PRINCETON
ILLINOIS...TO ABOUT MINUS 15 NEAR INDEPENDENCE. THIS AFTERNOON THEY
WILL BE BETWEEN 5 BELOW AND 10 ABOVE. WITH THE COLDER MINS SATURDAY
MORNING...WIND CHILLS WILL DROP TO BETWEEN 5 BELOW AND 18 BELOW ZERO.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 307 AM CST FRI DEC 6 2013
BELOW NORMAL TEMPERATURES ARE THE RULE THROUGHOUT THE EXTENDED
FORECAST. CHANCES FOR MEASURABLE SNOW CONTINUE FOR SUNDAY AND SUNDAY
NIGHT AS UPPER LEVEL IMPULSE IN THE NEARLY MERIDIONAL FLOW CURRENTLY
ALONG THE PACIFIC NW COAST ROUNDS THE BASE OF THE UPPER LEVEL TROUGH
AND PASSES THROUGH THE FORECAST AREA.
SATURDAY INTO SATURDAY NIGHT WILL BE DRY AND COLD AS HIGH PRESSURE
OVER THE NORTHERN ROCKIES PLAINS MIGRATES SE THROUGH THE AREA. WITH
A SIMILAR AIRMASS IN PLACE AS FRIDAY...HIGHS WILL ONLY MAKE THE
TEENS TO NEAR 20 IN THE FAR SOUTH. CLOUDS THICKEN SATURDAY NIGHT AS
MID AND UPPER LEVEL MOISTURE AND MODEST LIFT INCREASES AHEAD OF THE
APPROACHING SHORTWAVE. A DEVELOPING E-SE FLOW OF DRY AIR FROM THE
SURFACE THROUGH 850 MB SHOULD EFFECTIVELY EAT AWAY AT ANY ICE
CRYSTALS...HOLDING OFF THE ONSET OF FLURRIES UNTIL DAYLIGHT SUNDAY.
THE CLOUD COVER SHOULD KEEP MINIMUM TEMPERATURES WARMER THAN
PREVIOUS NIGHTS...FROM AROUND 10 NORTH TO THE LOWER TEENS ELSEWHERE.
SUNDAY AND SUNDAY NIGHT...LIGHT SNOW WILL OVERSPREAD THE AREA FROM
WEST TO EAST AS THE UPPER LEVEL VORT MAX AND INVERTED SURFACE TROUGH
MOVE THROUGH THE REGION. WHILE THERE ARE STILL MINOR DIFFERENCES
BETWEEN MODELS...THE OVERALL TREND IS TOWARD THE BEST UPPER LEVEL
FORCING PASSING OVERHEAD FROM MIDDAY INTO EARLY EVENING. MODEL QPF
AMOUNTS OF ROUGHLY .05 TO NEARLY .20...ALONG WITH A BRIEF WINDOW OF
LIFT IN THE IDEAL DENDRITIC GROWTH ZONE AND SURFACE TEMPERATURES
ONLY REACHING THE 20S...WOULD SUPPORT WIDESPREAD SNOWFALL AMOUNTS OF
AROUND 1 TO 3 INCHES. THE HIGHER TOTALS WILL LIKELY BE ACROSS THE NW
AND NORTH WITH LIGHTEST AMOUNTS IN THE SOUTHEAST. THE VORT MAX
PASSES TO THE NORTHEAST AFTER MIDNIGHT...ENDING THE LIGHT SNOW.
ALLOWING FOR SOME POSSIBLE FURTHER SLOWING OF THE SYSTEM...HAVE KEPT
CHANCE POPS GOING IN THE WEST...WHILE LIKELY POPS HANG ON IN THE FAR
NORTHEAST THROUGH THE NIGHT.
MONDAY THROUGH THURSDAY...THE FORECAST IS KEPT COLD AND DRY. THERE
WILL HOWEVER BE PERIODIC WEAK CLIPPER SYSTEMS IN THE MAINLY NW FLOW
ALOFT TO PROVIDE AT LEAST LOW CHANCES FOR FLURRIES OR LIGHT SNOW IN
THE VICINITY. AT THIS TIME...MODELS HAVE THE FIRST ONE PASSING TO
THE NORTHEAST ON TUESDAY...WITH ANOTHER AROUND WED OR WED NIGHT
POSSIBLY TAKING A MORE DIRECT PATH...BUT WITH SIGNIFICANTLY
DIFFERENT TIMING BETWEEN THE GFS AND ECMWF NO MENTION OF
PRECIPITATION IS INCLUDED IN THE FORECAST AT THIS TIME. THE BIGGER
STORY WILL BE THE CONTINUED COLD TEMPERATURES AS 850 MB TEMPERATURES
REMAIN IN THE SUB ZERO TEENS. FORECAST HIGHS IN THE TEENS TO MID 20S
AND LOWS IN THE SINGLE DIGITS MON THROUGH WED MAY BE TOO
OPTIMISTIC...ESPECIALLY IF THE SUNDAY SYSTEM LAYS NEW SNOW COVER
ACROSS THE AREA. THURSDAY AND BEYOND...THERE IS INDICATION OF A
WARMING TREND AS A SYSTEM DEVELOPS OUT WEST AND THIS IS REFLECTED
WITH HIGHS IN THE 20S TO POSSIBLY LOWER 30S IN THE SOUTH THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1150 PM CST THU DEC 5 2013
PATCHY LOW CLOUDS WITH AN OCCASIONAL MVFR CIG ARE CURRENTLY BEING
FOUND OVER NORTHEAST IOWA. LATEST RAP MODEL OUTLIER WITH
INCREASING THE LOW CLOUDS AND ADVECTING SOUTHEAST OVER MUCH OF
AREA ESPECIALLY NORTH OF I-80 OVERNIGHT AND FRIDAY MORNING.
WHILE SOME PRESENCE OF LOW LEVEL THETA-E AXIS AND LOW LEVEL
FRONTOGENESIS COULD FOSTER ADDITIONAL LOW CLOUDS NOT VERY CONFIDENT
TO MENTION ANY CIGS... BUT DID MAINTAIN SCATTERED CLOUD BASES
AROUND 2KFT AGL ONLY AT KDBQ FOR NOW BEING CLOSER TO THE ABOVE
MENTIONED FEATURES. OTHERWISE...VFR CONDITIONS WITH MID/HIGH
CLOUDINESS FROM STORM SYSTEM PASSING TO OUR SOUTH ON FRIDAY. WINDS
WILL REMAIN GENERALLY NORTHWEST AROUND 10-15 KTS WITH SOME LOCALLY
HIGHER GUSTS POSSIBLE AT TIMES.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...14
SHORT TERM...14
LONG TERM...SHEETS
AVIATION...05
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1150 PM CST THU DEC 5 2013
.SYNOPSIS...
ISSUED AT 318 PM CST THU DEC 5 2013
THE LATEST SFC ANALYSIS WAS INDICATING LARGE CANADIAN RIDGE AXIS
DRAPED FROM MT...DOWN INTO THE SOUTHEASTERN PLAINS AND LOWER MS RVR
VALLEY. THIS TO THE WEST OF LINGERING CYCLONIC PRESSURE GRADIENT
ACRS THE UPPER MS RVR VALLEY AND WESTERN GRT LKS AS OCCLUDED SFC LOW
COMPLEX SPIRALS JUST WEST OF JAMES BAY. VIS SATELLITE LOOP INDICATING
ESTABLISHED SNOW FIELDS ACRS MT...THE DAKOTAS...NORTHERN NEB...MN AND
NW WI. COLD LLVL NORTHWEST FETCH OFF THESE SNOW AREAS AND DOWN ACRS
IA. ALOFT...12Z UPPER AIR ANALYSIS AND MID/UPPER LEVEL MOISTURE FLOW
PATTERNS ON WATER VAPOR IMAGERY LOOP WAS SHOWING DEEP L/W TROF ACRS
MUCH OF THE WESTERN CONUS PIVOTING ACRS THE NORTHERN BAJA...WHILE
NEARLY STACKED UPPER LOW WAS ROLLING NORTHEASTWARD JUST WEST OF JAMES
BAY. THE W/V LOOP ALSO SHOWING LARGE SCALE/LONG FETCH MOISTURE FEED
FROM WELL WEST OF THE BAJA CA....UP ACRS MUCH OF THE SOUTHEASTERN
HALF OF THE CONUS.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 318 PM CST THU DEC 5 2013
TONIGHT...ALTHOUGH THE NORTHWESTERLY SFC WINDS WILL DECREASE TO
AROUND 10 TO 12 MPH OVERNIGHT...COLD AIR ADVECTION MACHINE STILL IN
FULL GEAR FROM NORTHERN PLAINS SOURCE REGION. STILL EXPECT ROUNDS
OF VARYING THICKNESS CIRRUS AND POSSIBLY SOME HIGHER BASED AC OFF
OVERRUNNING WINTER STORM SYSTEM ONGOING ACRS THE SOUTHERN PLAINS AND
UP THE OH RVR VALLEY. THUS MOSTLY CLOUDY TONIGHT...LITTLE OR NO
SNOW COVER...AND MIXING WINDS OF 10+ MPH WILL KEEP TEMPS FROM
BOTTOMING OUT TO SUBZERO READINGS. BUT STILL A COLD NIGHT IN STORE
WITH LOWS IN THE LOWER SINGLE DIGITS ABOVE ZERO IN THE FAR WEST AND
NORTHWEST...5-10 ABOVE TO THE MS RVR...AND LOWER TO MID TEENS EAST
OF THE MS RVR. THESE TEMPS COMBINED WITH THE WINDS TO PRODUCE WIND
CHILLS FROM ZERO..TO 10-12 BELOW ZERO WEST OF THE MS RVR LATE
TONIGHT AND THROUGH 6 AM CST FRI AM. WILL KEEP THE FCST DRY FOR
NOW...BUT EXTRAPOLATING SOME OF THE ELEVATED SNOW BANDS IN SOUTH
CENTRAL KS NORTHEASTWARD...SOME CHC THAT THEY MAY CLIP THE FAR
SOUTHERN CWA OVERNIGHT. BUT IF THEY DO...WILL BANK ON DRIER LLVLS
TO LIMIT THEM TO FLURRIES.
FRIDAY...ANOTHER COLD DAY CHARACTERIZED BY FILTERED SUNSHINE BY
OVERRUNNING CLOUDS OFF STORM SYSTEM JUST OFF TO THE SOUTHEAST.
MOSTLY CLOUDY CONDITIONS AND NORTHWEST WINDS OF 10-20 MPH IN
LINGERING RIDGE PRESSURE GRADIENT AS IT TRIES TO MAKE HEADWAY AND
SLIDE THIS WAY. AGAIN...WILL KEEP THE FCST DRY BUT WOULD NOT BE
SURPRISED IF SOME OVERRUNNING FLURRIES OR EVEN LIGHT SNOW
OCCASIONALLY CLIP THE FAR SOUTHERN AND SOUTHEASTERN CWA FROM TIME
TO TIME. CLOUD COVER AND CONTINUED CAA TO LIMIT HIGH TEMP RECOVERY
TO THE MID TEENS IN THE NORTHWEST...TO THE UPPER TEENS OR AROUND 20
DEGREES ALONG AND EAST OF THE MS RVR. ..12..
.LONG TERM...(FRIDAY NIGHT THROUGH NEXT THURSDAY)
ISSUED AT 318 PM CST THU DEC 5 2013
THE COLD WEATHER LOOKS LIKE IT WILL BE LOCKED IN OVER THE REGION
THROUGH MUCH OF NEXT WEEK WITH THE MODELS KEEPING A PERSISTENT BROAD
H5 TROF OVER THE CENTRAL AND WESTERN U.S.
DRY AND COLD CONDITIONS ARE EXPECTED SATURDAY AS HIGH PRESSURE MOVES
EAST ACROSS NORTHERN IA AND SOUTHERN MN. LOW TEMPERATURES IN THE
SINGLE DIGITS LOOK REASONABLE WITH LIGHT WINDS IN THE WEAK GRADIENT
NEAR THE HIGH AND CLEAR SKIES. LITTLE MIXING DURING THE DAY SUPPORT
TEENS AND LOW 20S FOR HIGHS.
A S/W MOVING OUT OF SOUTHWESTERN U.S. TROF AXIS WILL SPREAD MID
CLOUDS OVER THE AREA SUNDAY NIGHT. A FLURRY CAN/T BE RULED OUT WEST
OF THE RIVER AFTER MIDNIGHT WITH A BROAD REGION OF ISENTROPIC LIFT
AND MOISTENING MID LEVELS AHEAD OF THE S/W. HOWEVER...LOW LEVELS
REMAIN DRY WHICH SHOULD PREVENT ANY MEASURABLE SNOW. THE INCREASING
CLOUD COVER SATURDAY NIGHT WILL KEEP TEMPERATURES FROM FALLING MUCH
WITH LOWS AROUND 10 EXPECTED.
ACCUMULATING SNOW IS EXPECTED SUNDAY AND SUNDAY NIGHT AS THE S/W
MOVES THROUGH THE REGION. THE GFS/ECM HAVE BEEN VERY CONSISTENT
PAINTING A BROAD AREA OF QPF OVER THE REGION WITH THIS S/W WITH
WATER EQUIVALENTS UP TO TWO TENTHS OF AN INCH. THE ECMWF HAS ALSO
BEEN CONSISTENT IN KEEPING THE HIGHER AMOUNTS OVER THE NORTHERN CWFA
WHICH LOOKS REASONABLE BASED ON THE THE TRACK OF THE VORT THROUGH
NORTHERN MO/ SOUTHERN IA. TEMPERATURES WILL BE COLD ENOUGH FOR SOME
HIGH SNOW TO LIQUID RATIOS...POSSIBLY UP TO 20 TO 1 OVER THE
NORTHERN CWFA. FOR NOW A CONSERVATIVE 17 TO 1 RATIO WAS USED WHICH
PRODUCED 24 HOUR SNOWFALL AMOUNTS OF 2 TO NEARLY 4 INCHES OVER THE
NORTHWEST HALF OF THE AREA BETWEEN 12Z SUNDAY AND 12Z MONDAY.
FORECAST SNOW AMOUNTS OVER THE SOUTHEAST HALF WERE IN THE 1 TO 2
INCH RANGE. WIND DURING THE EVENT SHOULD STAY AROUND 10KTS OR LESS
SO NO SIGNIFICANT BLOWING OR DRIFTING IS EXPECTED. THE SNOW SHOULD BE
EAST OF THE AREA BY MONDAY MORNING.
ANOTHER SHOT OF VERY COLD AIR IS PULLED SOUTH INTO THE REGION BEHIND
SUNDAYS SYSTEM. H8 TEMPS ARE PROGGED TO DIP TO -15 TO -20C BY
TUESDAY NIGHT. HIGHS NEXT WEEK SHOULD BE IN THE TEENS AND 20S WITH
LOWS MAINLY IN THE SINGLE DIGITS AND TEENS. THE ECM CONTINUES TO
SHOW A STRONG HIGH PRESSURE SYSTEM OVER THE REGION BY MID WEEK WITH
THIS MORNINGS 12Z RUN INCREASING THE PRESSURE TO 1045MB. IF THIS
VERIFIES AND THERE IS SNOW COVER THEN WE COULD SEE LOW TEMPERATURES
SIGNIFICANTLY COLDER THAN CURRENTLY FORECAST FOR THE MIDDLE OF THE
WEEK. THE GFS ON THE OTHER HAND CONTINUES TO SUGGEST ONE OR TWO WEEK
CLIPPER SYSTEM MOVING THROUGH WHICH WOULD ARGUE AGAINST EXTREMELY
COLD TEMPERATURES. DLF
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1138 PM CST THU DEC 5 2013
PATCHY LOW CLOUDS WITH AN OCCASIONAL MVFR CIG ARE CURRENTLY BEING
FOUND OVER NORTHEAST IOWA. LATEST RAP MODEL OUTLIER WITH
INCREASING THE LOW CLOUDS AND ADVECTING SOUTHEAST OVER MUCH OF
AREA ESPECIALLY NORTH OF I-80 OVERNIGHT AND FRIDAY MORNING.
WHILE SOME PRESENCE OF LOW LEVEL THETA-E AXIS AND LOW LEVEL
FRONTOGENESIS COULD FOSTER ADDITIONAL LOW CLOUDS NOT VERY CONFIDENT
TO MENTION ANY CIGS... BUT DID MAINTAIN SCATTERED CLOUD BASES
AROUND 2KFT AGL ONLY AT KDBQ FOR NOW BEING CLOSER TO THE ABOVE
MENTIONED FEATURES. OTHERWISE...VFR CONDITIONS WITH MID/HIGH
CLOUDINESS FROM STORM SYSTEM PASSING TO OUR SOUTH ON FRIDAY. WINDS
WILL REMAIN GENERALLY NORTHWEST AROUND 10-15 KTS WITH SOME LOCALLY
HIGHER GUSTS POSSIBLE AT TIMES.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...12
SHORT TERM...12
LONG TERM...DLF
AVIATION...05
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1207 AM CST Fri Dec 6 2013
...UPDATED AVIATION...
.SYNOPSIS...
ISSUED AT 1115 AM CST THU DEC 5 2013
At 12z Thursday a 1400-160kt 300mb jet extended from northeast
Colorado into the western Great Lakes. Another upper level jet was
located near the based of the 500mb trough that was positioned from
southern California into southwest Montana. A -25 to -32c 500mb
thermal trough was located near the four corners region. A surface
to 850mb ridge axis was located across from western Nebraska into
western Oklahoma and a surface cold front extended from eastern
Colorado south southeast across eastern New Mexico into west
central Texas.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 217 PM CST THU DEC 5 2013
Upper level through that was located across southern California
and Nevada earlier today will track east and cross New Mexico by
late day. Ahead of this this upper trough some mid level moisture
will linger across western Kansas. Backing 700mb winds ahead of
this upper wave appears to enhance frontogenesis across portions
of southwest Kansas late today and early this evening which may
give rise to a period of steady light to moderate snow. Both the
NAM, GFS, and even the RAP hints at enhanced precipitation briefly
ahead of this wave along this baroclinic zone so will follow this
trend through midnight as the upper level trough moves out into
the central high plains. Given the potential for a period of
steadier snow early tonight could easily see snowfall
accumulations in the one to two inch range given the high liquid
to snow ratio. The area more favorable for this measurable
snowfall still appears to be along and south of a Ulysses to Dodge
City to Pratt line. Snow totals of around two inches still not out
of the question near the Oklahoma border so will trim several
counties out of the current winter weather advisory.
Tonight the dewpoint will be at or several degrees below zero
under mostly cloudy skies. Temperatures will be slow to fall this
evening but at this time given these expected low dewpoints, last
nights temperatures across northwest Kansas, and the low levels
cooling by a couple more degrees have decided to stay close to the
guidance for overnight lows. Given these overnight lows ranging
from around 1 degree in west central Kansas to near 10 degrees in
south central Kansas along with wind speeds of around 10 mph the
wind chills by early Friday morning are expected to fall back into
the -8 to -15 degree range. The coldest wind chills early Friday
morning will be across west central Kansas so will be issuing a
wind chill advisory for this area late tonight/early Friday.
On Friday the upper level trough will move east into the mid
Mississippi valley. Subsidence behind this disturbance may give
rise to some breaks of sun late in the day as high pressure at the
surface will continue to build into western Kansas. Despite to
break of sunshine the 900-850mb temperatures continue to support
highs only in the teens Friday afternoon.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 209 PM CST THU DEC 5 2013
Friday night:
Sfc high pressure will shift off to the east Friday night. This will
result in northeasterly winds eventually shifting southeast on the backside
of said departing high. A cold night is expected with minimums near
0F. Would not rule out a few negative values if skies clear more than
expected. Will have to watch for the potential for a wind chill advisory
during the overnight and morning hours.
Saturday and beyond:
The forecast becomes a bit more interesting during the weekend. An amplified
trof will eject from the central Rockies and out across the plains by
Sunday. This wave does have some upper level dynamics associated with
it (140-150 kt jet streak traverses across the forecast area of responsibility).
At the low levels, fairly intense warm air advection, 280-290 Kelvin
isentropic lift, and 850-600 mb increasing frontogenesis will lead
to snow late Saturday and into Sunday. The more enhanced area of said
parameters is forecast along and north of the 850 mb pressure perturbation
...basically the northern half of the forecast area. Models still show
low end snow advisory amounts along and north of highway 96. Even some
of the GEFS members show 2-4" of snow. There is huge bust potential
in temperatures for Sunday, should this snow/snow pack/cloud cover come
into fruition. The ECE shows a high of 8 for KDDC versus 22 from the
MEX. Will apply a slight bias towards the ECMWF solution versus the
GFS. Boise verification shows this guidance doing better than the
MEX with the current cold air mass over Kansas.
After Sunday, the forecast will remain precipitation free as isentropic
downglide and subsidence develops in the wake of the departing synoptic
trof. There is some question of when this cold air will be dislodged
and more of a low level 850 mb downslope plume will develop. The ECMWF
indicates this possibility of seeing "warmer" temperatures (i.e. above
freezing) by mid to late next week. The deterministic runs have been
fairly consistent over the last few days.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1206 AM CST FRI DEC 6 2013
We will need to watch closely for any IFR ceiling development
into the early morning as the back edge of the mid level cloud
shield exits the region. Enough mid level cloud should remain
however to keep low stratus development to a minimum, but the HRRR
does hint at the possibility of localized IFR/LIFR stratus
development which is too low of a chance to include in prevailing
or tempo groups.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 15 0 16 8 / 0 0 30 40
GCK 15 0 13 7 / 0 0 30 50
EHA 13 1 17 9 / 0 0 30 40
LBL 15 0 15 8 / 0 0 30 40
HYS 15 0 15 6 / 0 0 40 60
P28 21 4 20 10 / 10 0 40 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until 9 AM CST /8 AM MST/ this morning FOR
KSZ043-044-061>063.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Sugden
AVIATION...Russell
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
347 AM EST FRI DEC 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE TODAY AS A COLD FRONT APPROACHES
FROM THE WEST TONIGHT AND WILL CROSS THE REGION ON SATURDAY AFTERNOON.
A STRONGER COLD FRONT WILL CROSS THE REGION TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 320 AM FRIDAY...WITH A S/SSW WIND OF ABOUT 7 OR 8 KNOTS
LINGERING...TEMPERATURES ARE VERY MILD FOR BOTH THIS TIME OF YEAR
AND THIS TIME OF NIGHT...HOVERING IN THE MID TO UPPER 60S AREA-
WIDE. GIVEN THIS WARM START...MAXIMUM TEMPERATURES TODAY SHOULD BE
ABLE TO REACH THE UPPER 70S TO LOW 80S WELL INLAND WITH LOW TO MID
70S ALONG THE IMMEDIATE COAST. THINK RECORD LOWS MAY BE THREATENED
AT LOCATIONS SUCH AS GREENVILLE AND PERHAPS KINSTON LATER
TODAY...DESPITE FAIRLY THICK MID AND HIGH LEVEL CLOUDINESS. LATEST
HIGH RESOLUTION WRF AND RAP MODELS KEEP PRECIPITATION TO THE WEST
AND NORTH OF THE CWA TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
AS OF 325 AM FRIDAY...COLD FRONT WILL APPROACH THE REGION FROM THE
WEST LATER TODAY. BEST LOW-LEVEL MOISTURE TRANSPORT DOES NOT
ARRIVE IN OUR NORTHERN COUNTIES UNTIL AFTER MIDNIGHT AND WILL
SLOWLY RAMP POPS UP WITH CHANCE THRU THE LATE EVENING TO LIKELY
OVER NORTHERN COUNTIES BY LATE TONIGHT. QPF TOTALS THROUGH TONIGHT
DO NOT LOOK TO BE PARTICULARLY HEAVY...GENERALLY AT ONE-TENTH OF
AN INCH OR LESS. TEMPERATURES WILL VERY FROM THE MID TO UPPER 50S
ALONG THE FRONT OVER THE NORTHERN COUNTIES...TO THE MILD LOW AND
MID 60S AHEAD OF THE FRONT OVER THE SOUTHERN TWO-THIRDS OF THE
COUNTY WARNING AREA.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 330 AM FRI...MODELS CONTINUE IN GOOD AGREEMENT ON PUSHING A
SURFACE COLD FRONT THROUGH EASTERN NC SAT MORNING WITH TEMPS
WARMEST IN THE MORNING AND SLOWLY FALLING THROUGHOUT THE DAY DUE
TO CLOUDS AND PRECIP OVERSPREADING THE REGION FROM NW TO SE. THERE
WILL BE A LARGE GRADIENT BETWEEN HEIGHTS/THICKNESSES FROM THE
COASTAL PLAIN COUNTIES TO THE COAST...WITH TEMPS FALLING INTO THE
50S BEHIND THE FRONT. FRONTAL BOUNDARY WILL BE AN ANAFRONT WITH
CLOUD/PRECIP BEHIND THE FRONT. THE UPPER TROUGH WILL REMAIN
CENTERED OVER THE CENTRAL/WESTERN CONUS AS A STRONG RIDGE ALOFT
REMAINS CENTERED OVER FLORIDA...PLACING EASTERN NC IN SW FLOW
ALOFT THROUGH EARLY IN THE WEEK. A STRONG FRONTAL INVERSION WILL
BE PRESENT SAT THROUGH SUN AS 850MB WINDS REMAIN SW WITH NLY
SURFACE WINDS. THIS WILL PRODUCE WIDESPREAD RAIN AND LOW CLOUDS
THROUGH EARLY SUN MORNING. COOLER TEMPS EXPECTED ON SUNDAY DUE TO
CLOUDS/PRECIP WITH HIGHS IN THE 40S INLAND TO 50S ALONG THE COAST.
LATEST GUIDANCE CONTINUES TO INDICATE A COASTAL TROUGH DEVELOPING
SUN AFTERNOON...WHICH BECOMES A WEAK LOW THAT MOVES NNE ALONG THE NC
COAST SUN NIGHT. AS THE LOW MOVES NE OF THE AREA LATE SUN NIGHT/EARLY
MON MORNING...COLD AIR DAMMING SCENARIO WILL SHIFT NW OF THE REGION
AS SW RETURN FLOW TAKES OVER WITH EASTERN NC AGAIN IN THE WARM
SECTOR.
UPPER RIDGE WILL STRENGTHEN AGAIN MON WITH HIGH TEMPS EXPECTED
BACK INTO THE 70S UNDER PARTLY SUNNY SKIES. LOW LEVEL THICKNESSES
BUILD 1385-1390 METERS RANGE...BUT MIXED CLOUDS MAY INHIBIT FULL
INSOLATION SO HELD TEMPS IN THE LOW 70S INLAND TO UPPER 60S
OBX...ALTHOUGH GREATER BREAKS IN CLOUD COVER COULD MEAN TEMPS
REACHING A FEW DEGREES HIGHER THAN CURRENTLY FORECAST.
ANOTHER COLD FRONT WILL PASS THROUGH EASTERN NC EARLY TUES MORNING
BRINGING MORE UNSETTLED WEATHER WITH RAIN AGAIN MOSTLY POST-
FRONTAL AND CONTINUING INTO TUES EVENING BEFORE STRONG HIGH PRESSURE
OVER THE CENTRAL CONUS SHIFTS EAST OVER THE MID-ATLANTIC REGION.
WED/THURS WILL BE DRY AND MUCH COOLER WITH TEMPS STRUGGLING TO
BUILD INTO THE MID 40S DUE TO STRONG COLD AIR ADVECTION IN NLY FLOW.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 325 AM FRIDAY...GIVEN A S/SW WIND IN THE 6 TO 8 KNOT
RANGE...DO NOT EXPECT MUCH IN THE WAY OF DENSE FOG AT THE TAF
SITES. EXPECT VFR WITH INCREASING WSW WINDS THROUGH THE DAY FRIDAY.
WIND GUSTS 20-25 KT LIKELY FROM LATE MORNING THRU MID AFTERNOON
FRIDAY. GUIDANCE AGAIN INDICATES PATCHY DENSE FOG LATE FRIDAY
NIGHT...BUT WITH SOME LIGHT SW WINDS...AGAIN MAY BE LIMITED IN
SCOPE.
LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 335 AM FRI...A COLD FRONT WILL APPROACH FROM THE NW FRI
NIGHT...MOVING THROUGH THE TERMINALS SAT MORNING. MODEL SOUNDINGS
INDICATE A PROLONGED PERIOD OF MVFR/IFR CONDITIONS EXPECTED TO
DEVELOP LATE FRI NIGHT AND CONTINUE THROUGH MUCH OF SUNDAY...WITH
WIDESPREAD RAIN ALSO DEVELOPING THIS WEEKEND. N/NE WIND GUSTS
15-20KT EXPECTED BEHIND THE FRONT SAT AFTERNOON. A WEAK LOW OFF
THE COAST WILL PUSH NE THROUGH THE AREA SUN NIGHT WITH SW FLOW
TAKING OVER MON WITH PRECIP CHANCES DIMINISHING AND LOWER CIGS
LIFTING N OF THE REGION THOUGH FOG MAY BE A POSSIBILITY AT NIGHT.
ANOTHER COLD FRONT CROSS THE TERMINALS FROM NW TO SE TUES WITH
ANOTHER ROUND OF MVFR/IFR CONDITIONS POSSIBLE IN LOWERED
CEILINGS/VSBYS THROUGH TUES. HIGH PRESSURE BUILDS OVER THE REGION
TUES NIGHT WITH CONDITIONS IMPROVING TO VFR.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 325 AM FRIDAY...THE TIGHTENING PRESSURE GRAD AHEAD OF AN
APPROACHING COLD FRONT WILL RESULT IN INCREASING S-SW WINDS TO
15-20 KTS BY LATER THIS AFTERNOON...INCREASING TO 20 TO 25 KT
LATER TONIGHT. AS A RESULT...HAVE ISSUED A SMALL CRAFT ADVISORY
FOR THE COASTAL WATERS BEGINNING AT 03Z SATURDAY. SEAS ARE
CURRENTLY IN THE 2 TO 3 FOOT RANGE...BUT PER LOCAL NWPS/SWAN MODEL
AND WAVEWATCH GUIDANCE...SEAS WILL BUILD TO AS HIGH AS 6 FEET BY
LATE THIS EVENING AND TONIGHT.
LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 345 AM FRI...SCA CONDITIONS WILL PERSIST OVER THE WATERS
THROUGH THE WEEKEND AS SW WINDS INCREASE TO 20 KT OR HIGHER WITH
SEAS REACHING 6 FT FOR THE OUTER CENTRAL/SOUTHERN WATERS. FRONT
WILL PASS THROUGH THE WATERS BY MIDDAY SAT WITH NORTHERLY CAA
SURGE INCREASING WINDS TO 20 KNOTS WITH SEAS 5-7 FT THROUGH SUN
MORNING. MODELS IN AGREEMENT WITH A WEAK INVERTED/COASTAL TROUGH
OVER THE SOUTHERN/CENTRAL WATERS SUN AFTERNOON WHICH DEVELOPS INTO
A WEAK SURFACE LOW AND MOVES NNE ALONG THE NC COAST SUN NIGHT.
SURFACE WINDS WILL BECOME SW ONCE THE WEAK LOW LIFTS NORTH OF THE
WATERS LATE SUN NIGHT. WINDS AND SEAS BRIEFLY SUBSIDE BELOW SCA
CRITERIA MON MORNING WITH SW WINDS 10-15 KT AND SEAS 3-5 FT...THEN
INCREASE TO 15-20 KT AND SEAS 4-7 FT AS THE GRADIENT TIGHTENS
BETWEEN SURFACE RIDGE OFF THE SOUTHEASTERN COAST AND A COLD FRONT
APPROACHING FROM THE NW. SCA CONDITIONS EXPECTED MON AFTERNOON
LASTING THROUGH AT LEAST TUES. WAVEWATCH III AND LOCAL SWAN/NWPS
IN GOOD AGREEMENT THROUGH THE LONG TERM.
&&
.CLIMATE...
RECORD HIGH (79) WAS SET IN NEW BERN ON THURSDAY AND MORE RECORD
WARMTH LIKELY ON FRIDAY.
BELOW IS A SUMMARY OF THE
CLIMATOLOGICAL RECORD HIGH TEMPERATURES FOR FRIDAY...DECEMBER 6TH:
RECORD HIGH FOR DEC 6:
NEW BERN 81 (1998)
GREENVILLE 80 (1998)
KINSTON 81 (1982)
NEWPORT 77 (1998)
BAYBORO 82 (1998)
MOREHEAD CITY 74 (2011)
WILLIAMSTON 76 (1998)
CAPE HATTERAS 77 (1982)
OCRACOKE 73 (1975)
MANTEO 78 (1998)
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
SUNDAY FOR AMZ150-152-154.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST
SUNDAY FOR AMZ156-158.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...DAG
AVIATION...CTC/DAG
MARINE...CTC/DAG
CLIMATE...CTC
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
239 AM EST FRI DEC 6 2013
.SYNOPSIS...
A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE
TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TONIGHT THROUGH
FRIDAY...BRINGING PERIODS OF MIXED PRECIPITATION TO THE AREA. HIGH
PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE RECENTLY ACTIVE EARLY
SEASON WINTER WEATHER PATTERN ON SATURDAY. CONFIDENCE IS STEADILY
INCREASING FOR A PERIOD OF FROZEN AND FREEZING PRECIPITATION
SUNDAY INTO EARLY MONDAY THAT SHOULD EVENTUALLY CHANGE TO RAIN. AN
ARCTIC FRONTAL PASSAGE EARLY NEXT WEEK WILL DROP TEMPERATURES WELL
BELOW NORMAL THROUGH NEXT WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
FINE LINE ON KCCX RADAR SHOWING LOCATION OF COLD FRONT...JUST WEST
OF KUNV AND KAOO AT 0330Z. NEAR TERM MODELS AGREE IN TRACKING
COLD FRONT SE ACROSS THE AREA OVERNIGHT.
ALTHOUGH RAIN TAPERED OFF A BIT ACROSS CENTRAL PA EARLIER THIS
EVENING...REGIONAL RADAR MOSAIC SHOWING ANOTHER BATCH OF RAIN
APPROACHING FROM WESTERN PA AT 0330Z. UPSTREAM WATER VAPOR LOOP
SHOWS A SHORTWAVE OVR ILLINOIS AT 03Z...WHICH SHOULD LIFT NE
ACROSS THE E GRT LKS OVERNIGHT. LG SCALE FORCING AHEAD OF THIS
FEATURE SHOULD HELP SUPPORT NEXT BATCH OF PRECIP LATE THIS EVENING
THRU ARND 10Z. 02Z RAP FRONTOGENESIS PATTERNS MATCH WELL WITH
BAND OF SNOW FALLING FROM CENTRAL INDIANA TO NW OHIO. RAP INDICATES
THIS BAND OF ENHANCED FGEN LIFTS ACROSS NW PA BTWN 06Z-09Z AS MDL
SOUNDINGS BECOME COLD ENOUGH FOR SNOW. SO...BELIEVE A LIGHT SNOW
ACCUM IS POSSIBLE OVR WARREN/MCKEAN COS LATE TONIGHT.
FURTHER SOUTH...WILL RAMP UP CHC OF RAIN OVERNIGHT...AS SHORTWAVE
AND ASSOC LL JET/PLUME OF ANOMALOUS PWATS LIFTS THRU. BLEND OF
LATEST LAMP/RAP/NAM INDICATE TEMPS BEHIND CDFRONT WILL COAST
DOWNWARD TO THE U20S BY DAWN OVR THE NW MTNS...THE 30S MOST OF
CENTRAL PA...AND THE M40S ACROSS THE LOWER SUSQ VALLEY.
HAVE INCREASED WSPEEDS OVERNIGHT BASED ON UPSTREAM REPORTS AND
BUFKIT SOUNDINGS...WHICH SUPPORT A PERIOD OF GUSTS ARND 20KTS IN
IN THE NW FLOW IN WAKE OF FRONTAL PASSAGE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
NEXT SHORTWAVE LIFTING OUT OF THE S PLAINS WILL SPAWN A WAVE OF
LOW PRESSURE ALONG QUASI-STATIONARY SFC FRONT S OF PA ON FRIDAY
WITH ANOTHER SLUG OF PRECIP FOR FRIDAY AFTERNOON AND EVENING.
STRONG FRONTOGENETIC FORCING WILL DEVELOP UNDER THE ENTRANCE
REGION OF A VERY STRONG JET STREAK THAT WILL RACE DOWN THE ST
LAWRENCE RIVER VALLEY. THE BIGGEST ISSUE WITH THE SECOND WAVE WILL
BE THE AMOUNT OF WINTRY WEATHER ASSOCIATED. LATEST ENSEMBLE AND
OPER GUIDANCE SUGGESTS AIR MASS WILL BE COLD ENOUGH TO SUPPORT
SNOW ACROSS THE N COUNTIES...AS THE HEAVIEST PRECIP ARRIVES FRIDAY
AFTN. FURTHER SOUTH...LATEST MDL SOUNDINGS SUPPORT RAIN CHANGING
TO A WINTRY MIX ACROSS THE CENTRAL COUNTIES FRIDAY EVENING...AND
MAINLY RAIN OVER ABOUT THE SERN 1/3 OR SO OF MY FCST AREA.
BLENDED MDL QPF SUPPORTS A 3-5 INCH SNOWFALL ACROSS THE N
TIER...WITH JUST ENUF OF A WINTRY MIX OVER THE CENTRAL COUNTIES
TO POTENTIALLY CREATE SLIPPERY ROADS DURING THE EVENING. ACROSS
THE LAUREL HIGHLANDS...WARM AIR ALOFT SHOULD PRECLUDE MUCH SNOW.
HOWEVER...THE HIGHER TERRAIN DOWN THERE STILL LOOKS SUSCEPTIBLE TO
A PERIOD OF FZRA FRIDAY EVENING. HAVE THEREFORE...MOVED BACK THE
START TIME OF THEIR ADVISORY TO 22Z.
DEEPENING COLD AIR WILL ADVECT INTO THE STATE LATE FRIDAY NIGHT WITH
LINGERING LIGHT SNOW/MIXED PRECIP TAPERING OFF QUICKLY ARND
MIDNIGHT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE OVER THE UPPER MIDWEST
SATURDAY WILL MIGRATE EASTWARD INTO THE NORTHERN MID-ATLANTIC
STATES BY SUNDAY MORNING...SETTING THE STAGE FOR WHAT APPEARS TO
BE A CLASSIC OVERRUNNING MIXED PRECIP EVENT FOR LATER SUNDAY INTO
MONDAY.
05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES
INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING
FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS.
THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN
CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES
SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN
NEW ENGLAND.
DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH
THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM
AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A
BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR
ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN
LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS
MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG
AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES
VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY
AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM
ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS
AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION
MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW
INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD
FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE
LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA.
WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE
IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING
ASSUMING MOD-HVY ICING VIA FZRA.
IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE
REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW
NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD
CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW
COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE
INTO SW NY.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
ARES OF SHOWERS WILL CONTINUE TO STREAM THROUGH THE REGION
OVERNIGHT. THIS STEADY WAVE OF RAIN MOVING THROUGH CENTRAL PA.
LIFR WILL CONTINUE OVER THE LOWER SUSQ TERMINALS WHERE FOG IS
STILL LOCALLY DENSE. OTHERWISE...MVFR AND LOWER FLIGHT CATEGORIES
WILL CONTINUE INTO THIS MORNING AS MORE RAIN...SNOW...AND WINTRY
MIX OVERSPREAD THE REGION.
OUTLOOK...
FRI...MVFR IN RAIN SE. IFR IN SNOW/WINTRY MIX NW.
SAT...MVFR SNOW SHOWERS IN THE MOUNTAINS. VFR IN CENTRAL/EASTERN
AREAS.
SUN...REDUCTIONS DEVELOPING WITH APPROACHING STORM THAT WILL BRING
A WINTRY MIX SPREADING SOUTH TO NORTH INTO SUN NIGHT.
MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 5 AM EST
SATURDAY FOR PAZ004>006-010>012-017-018-037-041-042.
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM EST
SATURDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LA CORTE/STEINBUGL
LONG TERM...STEINBUGL
AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1153 PM EST THU DEC 5 2013
.SYNOPSIS...
A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE
TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TONIGHT THROUGH
FRIDAY...BRINGING PERIODS OF MIXED PRECIPITATION TO THE AREA. HIGH
PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE RECENTLY ACTIVE EARLY
SEASON WINTER WEATHER PATTERN ON SATURDAY. CONFIDENCE IS STEADILY
INCREASING FOR A PERIOD OF FROZEN AND FREEZING PRECIPITATION
SUNDAY INTO EARLY MONDAY THAT SHOULD EVENTUALLY CHANGE TO RAIN. AN
ARCTIC FRONTAL PASSAGE EARLY NEXT WEEK WILL DROP TEMPERATURES WELL
BELOW NORMAL THROUGH NEXT WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
FINE LINE ON KCCX RADAR SHOWING LOCATION OF COLD FRONT...JUST WEST
OF KUNV AND KAOO AT 0330Z. NEAR TERM MODELS AGREE IN TRACKING
COLD FRONT SE ACROSS THE AREA OVERNIGHT.
ALTHOUGH RAIN TAPERED OFF A BIT ACROSS CENTRAL PA EARLIER THIS
EVENING...REGIONAL RADAR MOSAIC SHOWING ANOTHER BATCH OF RAIN
APPROACHING FROM WESTERN PA AT 0330Z. UPSTREAM WATER VAPOR LOOP
SHOWS A SHORTWAVE OVR ILLINOIS AT 03Z...WHICH SHOULD LIFT NE
ACROSS THE E GRT LKS OVERNIGHT. LG SCALE FORCING AHEAD OF THIS
FEATURE SHOULD HELP SUPPORT NEXT BATCH OF PRECIP LATE THIS EVENING
THRU ARND 10Z. 02Z RAP FRONTOGENESIS PATTERNS MATCH WELL WITH
BAND OF SNOW FALLING FROM CENTRAL INDIANA TO NW OHIO. RAP INDICATES
THIS BAND OF ENHANCED FGEN LIFTS ACROSS NW PA BTWN 06Z-09Z AS MDL
SOUNDINGS BECOME COLD ENOUGH FOR SNOW. SO...BELIEVE A LIGHT SNOW
ACCUM IS POSSIBLE OVR WARREN/MCKEAN COS LATE TONIGHT.
FURTHER SOUTH...WILL RAMP UP CHC OF RAIN OVERNIGHT...AS SHORTWAVE
AND ASSOC LL JET/PLUME OF ANOMALOUS PWATS LIFTS THRU. BLEND OF
LATEST LAMP/RAP/NAM INDICATE TEMPS BEHIND CDFRONT WILL COAST
DOWNWARD TO THE U20S BY DAWN OVR THE NW MTNS...THE 30S MOST OF
CENTRAL PA...AND THE M40S ACROSS THE LOWER SUSQ VALLEY.
HAVE INCREASED WSPEEDS OVERNIGHT BASED ON UPSTREAM REPORTS AND
BUFKIT SOUNDINGS...WHICH SUPPORT A PERIOD OF GUSTS ARND 20KTS IN
IN THE NW FLOW IN WAKE OF FRONTAL PASSAGE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
NEXT SHORTWAVE LIFTING OUT OF THE S PLAINS WILL SPAWN A WAVE OF
LOW PRESSURE ALONG QUASI-STATIONARY SFC FRONT S OF PA ON FRIDAY
WITH ANOTHER SLUG OF PRECIP FOR FRIDAY AFTERNOON AND EVENING.
STRONG FRONTOGENETIC FORCING WILL DEVELOP UNDER THE ENTRANCE
REGION OF A VERY STRONG JET STREAK THAT WILL RACE DOWN THE ST
LAWRENCE RIVER VALLEY. THE BIGGEST ISSUE WITH THE SECOND WAVE WILL
BE THE AMOUNT OF WINTRY WEATHER ASSOCIATED. LATEST ENSEMBLE AND
OPER GUIDANCE SUGGESTS AIR MASS WILL BE COLD ENOUGH TO SUPPORT
SNOW ACROSS THE N COUNTIES...AS THE HEAVIEST PRECIP ARRIVES FRIDAY
AFTN. FURTHER SOUTH...LATEST MDL SOUNDINGS SUPPORT RAIN CHANGING
TO A WINTRY MIX ACROSS THE CENTRAL COUNTIES FRIDAY EVENING...AND
MAINLY RAIN OVER ABOUT THE SERN 1/3 OR SO OF MY FCST AREA.
BLENDED MDL QPF SUPPORTS A 3-5 INCH SNOWFALL ACROSS THE N
TIER...WITH JUST ENUF OF A WINTRY MIX OVER THE CENTRAL COUNTIES
TO POTENTIALLY CREATE SLIPPERY ROADS DURING THE EVENING. ACROSS
THE LAUREL HIGHLANDS...WARM AIR ALOFT SHOULD PRECLUDE MUCH SNOW.
HOWEVER...THE HIGHER TERRAIN DOWN THERE STILL LOOKS SUSCEPTIBLE TO
A PERIOD OF FZRA FRIDAY EVENING. HAVE THEREFORE...MOVED BACK THE
START TIME OF THEIR ADVISORY TO 22Z.
DEEPENING COLD AIR WILL ADVECT INTO THE STATE LATE FRIDAY NIGHT WITH
LINGERING LIGHT SNOW/MIXED PRECIP TAPERING OFF QUICKLY ARND
MIDNIGHT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE OVER THE UPPER MIDWEST
SATURDAY WILL MIGRATE EASTWARD INTO THE NORTHERN MID-ATLANTIC
STATES BY SUNDAY MORNING...SETTING THE STAGE FOR WHAT APPEARS TO
BE A CLASSIC OVERRUNNING MIXED PRECIP EVENT FOR LATER SUNDAY INTO
MONDAY.
05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES
INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING
FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS.
THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN
CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES
SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN
NEW ENGLAND.
DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH
THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM
AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A
BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR
ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN
LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS
MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG
AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES
VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY
AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM
ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS
AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION
MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW
INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD
FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE
LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA.
WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE
IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING
ASSUMING MOD-HVY ICING VIA FZRA.
IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE
REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW
NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD
CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW
COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE
INTO SW NY.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
NEXT WAVE OF STEADY RAIN MOVING INTO CENTRAL PA ATTM. THIS WILL
LEAD TO SOME IMPROVEMENT OF LIFR VSBYS...AT LEAST FOR AT TIME
WHILE IT IS RAINING OVER THE NEXT SEVERAL HOURS. UNTIL STEADIER
RAIN REACHES EAST...LIFR WILL CONTINUE OVER THE LOWER SUSQ
TERMINALS WHERE FOG IS STILL LOCALLY DENSE. OTHERWISE...MVFR AND LOWER
FLIGHT CATEGORIES WILL CONTINUE INTO FRIDAY AS MORE
RAIN...SNOW...AND WINTRY MIX OVERSPREAD THE REGION.
OUTLOOK...
FRI...MVFR IN RAIN SE. IFR IN SNOW/WINTRY MIX NW.
SAT...MVFR SNOW SHOWERS IN THE MOUNTAINS. VFR IN CENTRAL/EASTERN
AREAS.
SUN...REDUCTIONS DEVELOPING WITH APPROACHING STORM THAT WILL BRING
A WINTRY MIX SPREADING SOUTH TO NORTH INTO SUN NIGHT.
MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 1 PM FRIDAY TO 5 AM EST SATURDAY
FOR PAZ004>006-010>012-017-018-037-041-042.
WINTER WEATHER ADVISORY FROM 5 PM FRIDAY TO 5 AM EST SATURDAY
FOR PAZ024-033.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LA CORTE/STEINBUGL
LONG TERM...STEINBUGL
AVIATION...GARTNER/COLBERT
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1140 PM CST THU DEC 5 2013
.DISCUSSION...
SEE THE 06Z AVIATION DISCUSSION BELOW.
40
&&
.AVIATION...
MAIN FORECAST ITEMS OF CONCERN WILL BE CEILINGS AND WINDS. MODEL
FORECAST SOUNDINGS KEEP IFR THROUGH FRIDAY MORNING...WITH THE
CEILINGS LIFTING TO MVFR DURING THE AFTERNOON PERIOD. THE
SOUNDINGS DO NOT SUPPORT MUCH IN THE WAY OF CONVECTION...AND FELT
LIGHT DRIZZLE WILL MOST LIKELY OCCUR. WINDS ALONG THE COAST WILL
LIKELY GUST TO ABOVE 25 KNOTS OVERNIGHT TONIGHT AND SHOULD PERSIST
AT KGLS THROUGH FRIDAY AFTERNOON.
THE GUIDANCE SUGGESTS MVFR CONDITIONS LIFTING FRIDAY EVENING FROM
ABOUT HOUSTON SOUTH TO THE COAST. HOWEVER...THE MODEL FORECAST
SOUNDINGS INDICATE THAT MVFR CONDITIONS WILL LIKELY LOWER TOWARD
IFR DURING THE LATE EVENING. WITH COLD AIR ADVECTION COUPLED WITH
THE STRENGTHENING SURFACE PRESSURE GRADIENT...THE WINDS ALONG THE
IMMEDIATE COAST WILL LIKELY STRENGTHEN FRIDAY EVENING TO GUST TO
AROUND 30 KNOTS AT KGLS BEGINNING AROUND 00Z. OVER THE INLAND
SITES...FELT THAT THE GUIDANCE WAS ON TRACK IN DIMINISHING THE
WIND GUSTS AROUND SUNSET.
40
&&
.PREV DISCUSSION... /ISSUED 928 PM CST THU DEC 5 2013/
UPDATE...
UPDATE TO ISSUE A WIND ADVISORY FOR THE COASTAL COUNTIES.
DISCUSSION...
WIND SPEEDS HAVE INCREASED AND WIND ADVISORY CRITERIA HAS BEEN
MET ALONG THE COAST. A WIND ADVISORY WILL BE IN EFFECT THROUGH 4
AM FOR THE COASTAL COUNTIES.
CONCERN IS GROWING FOR WINTER PRECIP OVER THE NW ZONES TONIGHT.
TEMPS ARE GETTING DANGEROUSLY CLOSE TO FREEZING. JACKSONVILLE AND
PALASTINE ARE BOTH REPORTING SLEET. SFC DEW PTS CONTINUE TO DROP
AND AM CONCERNED ABOUT EVAPORATIVE COOLING LOWERING SFC TEMPS TO
NEAR OR JUST BELOW FREEZING. NAM 12 FCST SOUNDINGS SHOW SFC TEMPS
FALLING TO 32 DEGREES AT 09Z AND 31 DEGREES 12Z-18Z. THE NAM12 SFC
DEW PT FIELD IS WARMER SO THERE ARE CONFLICTING SIGNALS BETWEEN
SFC PARAMETERS AND SOUNDING PARAMETERS. AM STRONGLY CONSIDERING A
WINTER WEATHER ADVISORY FOR AREAS NW OF A CALDWELL TO CROCKETT
LINE FOR OVERNIGHT INTO FRI MORNING. 43
PREV DISCUSSION... /ISSUED 805 PM CST THU DEC 5 2013/
UPDATE...
SEE EVENING UPDATE.
DISCUSSION...
AT 01Z...A COLD FRONT EXTENDED FROM SOUTH CENTRAL LOUISIANA
ACROSS THE WESTERN GULF. A VERY TIGHT PRESSURE GRADIENT IS IN
PLACE AND WIND SPEEDS ARE APPROACHING ADVISORY CRITERIA. WILL
WATCH TRENDS BUT WILL HOLD OFF ON A WIND ADVISORY FOR THE COASTAL
COUNTIES FOR NOW. WATER TEMPS HAVE COOLED A BIT SINCE THE LAST
FROPA...SO FEEL THERMAL CONTRIBUTION TO WINDS WILL BE LESS THAN
PAST COUPLE OF EVENTS. RAP GUIDANCE ALSO SUGGESTS THAT WINDS WILL
REMAIN BELOW ADVISORY CRITERIA.
POPS ARE RATHER HIGH CONSIDERING THE RADAR LOOKS SO BENIGN AT THE
CURRENT TIME. 00Z 850 MB ANALYSIS SHOWS WINDS STILL OUT OF THE
SOUTH WITH AN 850 MB FRONT EXTENDING FROM TEXARKANA TO ABOUT
LAREDO. ISENTROPIC UPGLIDE HAS NOT REALLY KICKED IN YET AS NORTH
WINDS REMAIN VERY SHALLOW. THIS SHOULD CHANGE OVERNIGHT AS THE
850 MB FRONT CLEARS THE COAST. 00Z SOUNDINGS SHOW A SATURATED
LAYER FROM THE SURFACE TO 850 MB...AND VERY DRY AIR ABOVE THE
SATURATED LAYER. NAM12 AND RAP FORECAST SOUNDINGS CLOSELY MATCH
THE 00Z SOUNDINGS. THIS TYPE OF SOUNDING FAVORS DRIZZLE OVER RAIN.
EITHER WAY...EXPECT CONDS TO BECOME INCREASINGLY DAMP OVERNIGHT.
TEMP FCST LOOKS TO BE ON TRACK. NOT EXPECTING FREEZING TEMPS
OVERNIGHT BUT CALDWELL (RWV) IS GETTING CLOSE. CURRENT TEMP AT RWV
IS 34 DEGREES WITH A DEW PT OF 30. HAVE SOME CONCERN THAT DEW
POINTS NEAR 30 WILL ALLOW FOR SOME EVAPORATIVE COOLING ONCE PRECIP
BEGINS AND THEN INSTEAD OF DRIZZLE...WE GET FREEZING DRIZZLE.
WILL AGAIN WATCH TRENDS BUT FEEL CURRENT FCST HAS A GOOD HANDLE
ON TONIGHT`S TEMP/PRECIP TRENDS. HAVE MADE MINOR CHANGES TO THE
GRIDS. NEW ZFP OUT BY 900 PM. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 33 35 27 34 31 / 60 70 10 40 40
HOUSTON (IAH) 38 39 33 38 33 / 40 70 20 50 50
GALVESTON (GLS) 46 48 37 45 40 / 40 70 20 50 40
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...WIND ADVISORY UNTIL 4 AM CST FRIDAY FOR THE FOLLOWING ZONES:
BRAZORIA...CHAMBERS...GALVESTON...JACKSON...MATAGORDA.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST FRIDAY FOR THE FOLLOWING
ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS FROM FREEPORT
TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS
FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...43
AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1149 PM EST THU DEC 5 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT MOVES EAST INTO THE APPALACHIANS
TONIGHT. THE BOUNDARY CRAWLS ACROSS VIRGINIA ON FRIDAY. ARCTIC
HIGH PRESSURE WELL BEHIND THE FRONT WILL WEDGE SOUTH ALONG THE
MOUNTAINS SATURDAY...BEFORE INTERACTING WITH PRECIPITATION
RETURNING NORTH BY SUNDAY. SOUTHWESTERLY FLOW RETURNS MONDAY
BEFORE A STRONGER COLD FRONT ARRIVES LATE MONDAY NIGHT.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 745 PM EST THURSDAY...
A STRONG COLD FRONT LOCATED TO OUR WEST THIS AFTERNOON FROM CLE TO
LEX TO MEM WILL MOVE EAST TONIGHT INTO FRIDAY. WEAK SHORTWAVES MOVE
NORTHEAST IN THE WARM SECTION WILL RESULT IN SCATTERED SHOWERS.
INCREASED PROBABILITY OF PRECIPITATION IN THE FAR NORTHWEST COUNTY
WARNING AREA AND LEANED POPS THIS EVENING INTO TONIGHT TOWARDS A
BLEND OF THE LATEST RAP AND RNKWRFARW. THE GFS ALSO SHOWED SOME
LIGHT PRECIPITATION ALONG THE SOUTHERN BLUE RIDGE MOUNTAINS INTO
SOUTHERN VIRGINIA. THE MAIN BODY OF RAINFALL SHOULD REMAIN WILL
REMAIN TO OUR WEST TONIGHT.
A VERY WARM AND MUGGY OVERNIGHT EXPECTED WITH READINGS FROM
AROUND 50 DEGREES IN THE NORTHWEST MOUNTAINS TO THE LOWER 60S IN
THE SOUTHEAST.
SURFACE COLD FRONT WILL BE ENTERING THE MOUNTAINS FRIDAY WITH A WAVE
OF LOW PRESSURE WHICH DEVELOPS ALONG THE BOUNDARY AND RIPPLE
NORTHEAST ACROSS THE REGION. MAIN AXIS OF RAIN SHOULD BE FOCUSED
ALONG AND JUST WEST OF THE FRONTAL BOUNDARY FRIDAY. FELT THERE WAS
ENOUGH INSTABILITY TO INCLUDE THE MENTION OF AN ISOLATED
THUNDERSTORMS MAINLY WEST OF I77. PLAYED HIGH TEMPERATURES CLOSE
TO THE ADJMAVBC WITH VALUES FROM THE LOWER 50S IN THE MOUNTAINS TO
THE MID 70S IN THE PIEDMONT.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 315 PM EST THURSDAY...
NOT A LOT OF CHANGE EARLY ON WITH THE SLOW MOVING COLD FRONT AND
ASSOCIATED WAVE CROSSING THE REGION FROM THE NW FRIDAY NIGHT AND
SPILLING SOUTH OF THE AREA EARLY SATURDAY. MODELS AGAIN WEAKEN THE
AXIS OF LIFT ALONG/BEHIND THE FRONT FRIDAY EVENING WITH HEAVIEST QPF
AND HIGHEST POPS ALONG THE WESTERN SLOPES THROUGH LATE
EVENING...THEN LESS ALONG/EAST OF THE BLUE RIDGE EXCEPT SE WHERE THE
BOUNDARY MAY STALL AND THE LOW LEVEL NE FLOW MAY ENHANCE SHOWERS
LATE. STILL APPEARS ENOUGH MOISTURE ACROSS THE NW LATE FRIDAY NIGHT
TO WARRANT KEEPING IN SOME LIGHT MIX MENTION AT ELEVATION BUT
OVERALL THINK ANYTHING FROZEN AT THIS POINT QUITE SPOTTY ACROSS SE
WVA. COLD AIR WILL BE SLIDING IN FROM THE NORTH/WEST ALTHOUGH TEMPS
MAY ACTUALLY GET COLDER AFTER DAYBREAK SATURDAY WHEN THE BETTER 85H
COLD ADVECTION ARRIVES.
GUIDANCE HAS CONTINUED THE TREND FROM YESTERDAY IN PUSHING THE
DEEPER MOISTURE TO THE SE SATURDAY AS THE LARGE ARCTIC HIGH BUILDS
IN FROM THE NW AND INITIALLY GIVES THE MOISTURE A PUSH. MAY SEE THE
ENTIRE CWA GO DRY BY SATURDAY AFTERNOON BUT FOR NOW LEAVING IN SOME
POP MAINLY EASTERN HALF THROUGH MIDDAY AND MAINLY FAR SE LATE IN THE
DAY. COULD EVEN HAVE SOME CLEARING TAKE PLACE NW PENDING HOW STRONG
THE DRY ADVECTION IS SO CUT BACK ON CLOUD COVER SOME NORTH HALF
DURING THE AFTERNOON. HIGHS CHILLY WITH LOW LEVEL NORTH/NW FLOW WITH
TEMPS 30S WEST TO 40S/NEAR 50 FAR SOUTH.
MAIN CONCERN THEN WITH THE POTENTIAL FOR A SIGNIFICANT WINTER EVENT
FROM VERY LATE SAT NIGHT INTO SUNDAY AND PERHAPS SUNDAY NIGHT ACROSS
THE NORTH. LATEST GUIDANCE HAS AGAIN SLOWED THINGS UP A BIT WITH
LOTS OF COLD/DRY AIR SLIDING DOWN EAST OF THE BLUE RIDGE AS THE
STRONG WEDGE DEVELOPS WITH THE HIGH BUILDING FARTHER SOUTH. THIS
WILL MAKE FOR COLDER TEMPS SAT NIGHT BEFORE THICKENING CLOUDS AND
LIGHT PRECIP RETURN FROM THE SOUTH/SW AFTER MIDNIGHT PER ISENTROPIC
LIFT AHEAD OF ANOTHER WAVE HEADING UP WEST OF THE MOUNTAINS.
LATEST FORECAST SOUNDINGS SHOW DRY AIR HOLDING LONGER WITH PRECIP
NOT REACHING INTO THE SOUTHERN HALF OF THE AREA UNTIL AFTER MIDNIGHT
AND POINTS NORTH SUNDAY AROUND DAYBREAK. PRECIP THEN LOOKS TO
ACCELERATE INTO THE WEDGE SUNDAY MORNING FROM THE SW BUT REMAIN
INCONSISTENT IN QPF AMOUNTS WHICH ARE CRITICAL GIVEN COLDER PROFILES
FROM 12Z RUNS. HOWEVER MOST SHOWING THE BEST LIFT WITH A WARM
FRONT ALOFT TYPE FEATURE THAT DEVELOPS OVER THE CENTRAL/NORTHERN
CWA SUNDAY MORNING AND SHIFTS NORTH DURING THE AFTERNOON LEAVING
MORE SPOTTY NATURE PRECIP ELSW INTO SUNDAY EVENING. BOTH THE NAM
AND GFS ARE COLDER THAN THE EARLIER SOLNS WITH LESS OF A WARM NOSE
EARLY ON AND DEEPER LOW LEVEL COLD AIR SUPPORTIVE OF MORE OF A
SNOW/SLEET MIX AT THE ONSET ESPCLY HIWAY 460 NORTH. THUS INCLUDING
SOME LIGHT ACCUMULATIONS NW SUNDAY MORNING AS THINGS REMAIN BELOW
FREEZING AT 85H AND THINGS BECOME MORE ISOTHERMAL UNTIL THE
STRONGER WARM ADVECTION ARRIVES IN THE AFTERNOON. SOME SLEET ALSO
POSSIBLE ELSW AS THINGS WET BULB DOWN AT THE ONSET BUT THINKING
MORE OF A PROLONGED FREEZING RAIN EVENT ESPCLY SRN BLUE RIDGE AND
ACROSS THE VA COUNTIES SOUTH OF 460. WEDGE MAY BE ENOUGH TO FORCE
TEMPS DOWN ENOUGH TO PRODUCE SOME SPOTTY FZRA INTO NW NC BUT
HOLDING OFF GOING THAT COLD ATTM. OTRW FEW CHANGES TO HIGH POPS
SUNDAY WITH HIGH POPS FOR LOW QPF SUNDAY NIGHT WHEN THE GREENBRIER
VALLEY AND SRN SHENANDOAH VALLEY MAY HOLD ONTO FREEZING RAIN
OVERNIGHT. SINCE MOSTLY A 6TH PERIOD AND BEYOND EVENT...WILL HOLD
OFF ON HEADLINES FOR NOW AND KEEP MENTION IN THE HWO.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 350 PM EST THURSDAY...
COMPLICATED FORECAST CONTINUES THROUGH THE EXTENDED PERIODS AS
SOUTHWEST FLOW ALOFT CONTINUES ACROSS THE REGION AT THE SAME TIME
ARCTIC AIR CONTINUES TO STREAM SOUTHEASTWARD FROM WESTERN/CENTRAL
CANADA INTO THE CENTRAL AND EASTERN U.S. OUR REGION REMAINS ON OR
NEAR THE BOUNDARY BETWEEN THE ARCTIC AIR AND THE WARMER AIR TO THE
SOUTHEAST...HOWEVER...THROUGH THE LONGER TERM PERIODS IT APPEARS
THAT THE ARCTIC AIR WILL WIN OUT ACROSS OUR REGION AND THE FRONTAL
WILL FINALLY BE PUSHED INTO THE SE STATES AS THE UPPER FLOW
FINALLY BECOMES NW.
MON MORNING WE ARE STILL DEALING WITH THE END OF THE POTENTIAL
SIGNIFICANT ICING EVENT ADDRESSED IN THE SHORT TERM PERIODS AS THE
WEDGE BOUNDARY FINALLY LIFTS INTO NORTHERN VA. MODELS HAVE
CONTINUED TO TREND COLDER...WHICH REQUIRES HOLDING ONTO THE -FZRA
A FEW MORE HOURS INTO MID-MORNING MONDAY THAN EARLIER INDICATED.
WILL CHANGE ALL PRECIPITATION TO -RA BY 15Z MON AS THE FORECAST
AREA BRIEFLY MOVES INTO A WARM SECTOR SANDWICHED BETWEEN THE
RETREATING COLD AIR WEDGE AND THE NEXT SURGE OF ARCTIC AIR TO THE
WEST. THROUGH THE DAYLIGHT HOURS...WE SHOULD SEE ONLY LIQUID PCPN
ACROSS THE REGION.
BY 06Z TUE...THE NEXT SURGE OF ARCTIC AIR SHOULD MOVE INTO OUR WV
COUNTIES AND OUR FAR SW VA CONTINUES. GIVEN THE STRENGTH OF THIS
SECOND SURGE OF COLD AIR...WOULD EXPECT -RA TO QUICKLY CHANGE TO
-SN FROM WEST TO EAST DURING THE EVENING. AT THE SAME TIME...THE
DEEPER MOISTURE IS SHIFTING EAST INTO THE PIEDMONT WHERE AT THIS
POINT IT SHOULD STILL BE WARM ENOUGH FOR MOSTLY -RA. THUS...SNOW
ACCUMULATIONS OUTSIDE MOUNTAIN UPSLOPE -SHSN EASTERN WV...SHOULD
BE MINIMAL...BUT COULD NOT RULE OUT AN INCH OR SO IN SOME SPOTS
WEST OF I-81/I-77. THERE IS CONSIDERABLE DISCREPANCY BETWEEN THE
GFS/ECMWF IN THIS TIME FRAME...WITH THE ECMWF PUSHING THE MOISTURE
WELL EAST OF THE CWA BEFORE ANY APPRECIABLE COLD AIR MOVES INTO
THE REGION FROM THE WEST...WHILE THE GFS TRIES TO MOVE YET A THIRD
WAVE ALONG THE FRONTAL BOUNDARY ACROSS THE REGION FROM THE SW.
GIVEN THE OVERALL CONFLUENT FLOW IN THIS TIME FRAME...NOT
EXPECTING ANY SIGNIFICANT PCPN OR MORE IMPORTANTLY WINTER WX
ISSUES. AGAIN...HOWEVER...THERE WILL BE MOUNTAIN UPSLOPE
-SHSN...WITH MINOR SNOW ACCUMULATIONS EASTERN WV COUNTIES INTO FAR
SW VA AND THE NW NC MOUNTAINS.
FOR THE REMAINDER OF THE EXTENDED...AT THIS POINT IT APPEARS DRY.
THE CENTER OF THE ARCTIC AIR MASS DRIFTS OVER THE REGION BY THU
WITH A VERY DRY/COLD AIR MASS. AGAIN...THERE ARE CONSIDERABLE
DIFFERENCES BETWEEN THE ECMWF AND GFS WITH RESPECT TO TEMPERATURES
IN THIS TIME FRAME. GIVEN THE STRENGTH OF THIS ARCTIC AIR
MASS...HAVE LEANED HEAVILY TOWARD THE COLDER GFS. THE COLDEST DAY
SHOULD BE THU WHEN THE ARCTIC HIGH IS CENTERED RIGHT OVER THE CWA.
WOULD NOT BE THE LEAST SURPRISED TO SEE MIN TEMPERATURES IN THE
SINGLE DIGITS IN LOCATIONS SUCH AS LWB. HOWEVER...THE PREVAILING
WEST AS OPPOSED TO A STRONG NW-N FLOW ALOFT SHOULD RESULT IN THE
COLDER AIR REMAINING NORTH AND WEST OF THE CWA..SO WE SHOULD STAY
AOA 20 DEGREES FOR MINS ACROSS THE PIEDMONT. ANY PRECIPITATION
WED-FRI SHOULD BE CONFINED TO UPSLOPE MOUNTAIN -SHSN WITH DRIER
DOWNSLOPE WEST FLOW EAST OF THE ALLEGHANYS. EVEN ACROSS EASTERN
WV...SNOW ACCUMULATIONS SHOULD BE FAIRLY LIMITED WITH OVERALL
SNOW ACCUMULATIONS THERE EVEN AN INCH OR LESS.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 1145 PM EST THURSDAY...
STRONG COLD FRONT WILL BE APPROACHING FROM THE OHIO VALLEY...STALLING
WEST OF THE APPALACHIAN MOUNTAINS TONIGHT. A BROAD BAND OF RAIN
FROM CENTRAL PENNSYLVANIA TO CENTRAL TENNESSEE WILL BRING RAIN
WITH MVFR VISIBILITIES TO KLWB AND KBLF TONIGHT. STRATUS AND FOG
WITH SCATTERED SHOWERS IS EXPECTED FOR THE REST OF THE AREA.
CEILINGS WERE ALREADY MVFR AT 00Z/7PM. HIGH CONFIDENCE THAT
KROA...KBCB...KLYH AND KDAN WILL LOWER TO IFR OR LIFR OVERNIGHT WITH
MVFR FOG. LITTLE IMPROVEMENT IS EXPECTED ON FRIDAY. CEILINGS WILL
REMAIN IN THE IFR TO MVFR RANGE WITH RAIN BECOMING MORE
WIDESPREAD...ESPECIALLY IN THE LATE AFTERNOON AND EVENING.
EXTENDED AVIATION...A COLD FRONT WILL MAKE SLOW PROGRESS ACROSS
THE AREA LATE FRIDAY...RESULTING IN MVFR AND IFR CONDITIONS IN
ADDITION TO WIDESPREAD RAIN SHOWERS...BEFORE THE FRONT PASSES EAST
FRIDAY NIGHT INTO SATURDAY MORNING. MAY SEE A BRIEF IMPROVEMENT TO
VFR ON SATURDAY AS HIGH PRESSURE BUILDS IN FROM THE
NORTH...HOWEVER IFR WILL RETURN SATURDAY NIGHT AS ANOTHER SYSTEM
APPROACHES FROM THE SOUTHWEST...BRINGING FREEZING RAIN...SNOW AND
SLEET TO THE AREA SUNDAY. AN ARCTIC COLD FRONT WILL MOVE THROUGH
ON MONDAY...BRINGING A SLOW IMPROVEMENT TO VFR FOR TUESDAY.
HIGH PRESSURE IS EXPECTED TO PROVIDE FAIR WEATHER WITH VFR
CONDITIONS FROM TUESDAY THROUGH THURSDAY.
&&
.CLIMATE...
WARM TEMPERATURES THE NEXT COUPLE DAYS WILL APPROACH RECORDS AT THE
CLIMATE SITES. BELOW ARE THE CURRENT RECORDS.
DECEMBER 5 CURRENT RECORD HIGH TEMPERATURES (YEAR)
ROA76(2001)
LYH76(2001)
DAN 75(1982)
BCB70(2001)
BLF71(2001)
LWB68(2001)
DECEMBER 5 CURRENT RECORD HIGH MINIMUM TEMPERATURES (YEAR)
ROA58(1982)
LYH60(1982)
DAN57(1982)
BCB52(1982)
BLF55(1994)
LWB53(1994)
DECEMBER 6 CURRENT RECORD HIGH MINIMUM TEMPERATURES (YEAR)
ROA52(2011)
LYH52(2011)
DAN60(2011)
BCB51(2011)
BLF56(2011)
LWB 52 (1998)
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/KM
NEAR TERM...AMS/KK
SHORT TERM...JH
LONG TERM...RAB
AVIATION...AMS/KK
CLIMATE...CF
AREA FORECAST DISCUSSION
NWS NEW YORK NY
950 AM EST FRI DEC 6 2013
.SYNOPSIS...
A COLD FRONT CROSSES THE REGION EARLY TODAY. LOW PRESSURE RIDES THE
STALLED FRONT TONIGHT WITH HIGH PRESSURE BUILDING IN FOR THE
WEEKEND. LOW PRESSURE RETURNS SUNDAY NIGHT AND IMPACTS THE
NORTHEAST THROUGH THE FIRST HALF OF NEXT WEEK. HIGH PRESSURE
BUILDS IN FOR THE SECOND HALF.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE GOES WATER VAPOR IMAGERY TELLS THE PICTURE WITH A RIVER OF
MOISTURE FROM THE CENTRAL PACIFIC TO NEWFOUNDLAND.
SFC COLD FRONT SEEN ON RADAR AND IN THE OBS OFF SOUTH OF LONG
ISLAND AS OF 1430Z. LATEST HRRR AND RADAR SUPPORTS LIGHT RA
ENDING FROM WEST TO EAST FOR THE LUNCH HOUR AND THEN REFORMING
THIS AFTERNOON AS WAVE OF WEAK LOW PRESSURE RIDE ALONG THE FRONT.
TEMPS FALLING IN THE COLD ADVECTION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
CURRENTLY EVALUATING NEEDS FOR WINTER WX ADVISORY FOR ORANGE AND
PUTNAM COUNTIES. HOPE TO HAVE A DECISION BY 11 AM.
UPPER SW FLOW PREVAILS THIS TIME FRAME. COLD FRONT SAGS
FURTHER SOUTH IN TIME...AS RIDGE OF HIGH PRESSURE BUILDS FROM THE
WEST.
FOR TONIGHT...COLDER AIR CONTINUES TO FILTER IN FROM THE NORTH.
RAIN WILL BECOME WIDESPREAD OVER THE AREA...TO THE NORTH OF THE
WAVE OF LOW PRESSURE. A TRANSITION FROM RAIN TO SNOW/SLEET WILL
OCCUR FROM NORTH TO SOUTH AS THE NIGHT PROGRESSES.
AT THIS TIME...ANALYSIS OF MODEL SOUNDINGS AND LOW LEVEL
THICKNESS PROFILES WOULD SUGGEST RAIN AND SLEET IN THE EVENING
OVER THE NW ZONES WILL TRANSITION TO SNOW/SLEET IN TIME. MAINLY
RAIN NEAR THE COAST TONIGHT...WITH PERHAPS SOME SLEET MIXING IN
FROM TIME TO TIME...ESPECIALLY AFTER MIDNIGHT.
DO NOT FORESEE MUCH IN THE WAY OF FREEZING RAIN AND THUS SIGNIFICANT
ICING BEHIND THE FRONT. AS SUCH...NO WINTER HEADLINES ARE PLANNED AT
THIS TIME.
MINOR SNOW ACCUMS THOUGH ARE EXPECTED ACROSS THE INTERIOR BY SAT
MORNING. ORANGE COUNTY COULD SEE AN INCH OR TWO OF SNOW...ALONG WITH
SOME SLEET ACCUM.
CLOUDS IN THE MORNING GIVE WAY TO AFTERNOON SUNSHINE.
CHILLY TEMPS RANGING FROM AROUND 30 INLAND TO THE MIDDLE 30S NEAR
THE COAST LATE TONIGHT ARE ANTICIPATED. THEN TEMPS RISE TO THE UPPER
30S TO LOWER 40S SATURDAY...WHICH IS SLIGHTLY BELOW NORMAL. A
MET/MAV MOS BLEND FOLLOWED.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE KEEPS THE REGION DRY SATURDAY NIGHT AND MOST OF THE
DAYTIME HOURS OF SUNDAY WITH BELOW-NORMAL TEMPS.
FOR LATE-DAY SUNDAY THROUGH MONDAY NIGHT...MODELS IN GOOD AGREEMENT
THAT LOW PRESSURE SHIFTS IN FROM THE SOUTH AND WEST...BRINGING
PCPN MAINLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON. THERE IS A
CHANCE HOWEVER THAT THE SOUTHERNMOST PORTIONS OF THE FORECAST AREA
SEE SOME LIGHT SNOW OR FLURRIES DEVELOP RIGHT BEFORE SUNSET ON
SUNDAY. PCPN EVENTUALLY BECOMES LIKELY FOR THE CITY AND OTHER
SOUTHERN SECTIONS BY MIDNIGHT...THEN LIKELY FARTHER NORTH AND EAST
AROUND OR SHORTLY AFTER MIDNIGHT.
FORECAST BUFKIT SOUNDINGS SHOW AN ELEVATED WARM LAYER
DEVELOPING...RESULTING IN MIXED PCPN TYPES. COMPLICATING THE
PCPN TYPE FORECAST FURTHER WILL BE COOLING OF BOUNDARY LAYER AND
SURFACE TEMPS DUE TO WET-BULBING...FOLLOWED BY ONSHORE WINDS THAT
WOULD PUSH TEMPS BACK UP OVERNIGHT SUNDAY NIGHT.
DUE TO THE PCPN TYPE COMPLICATIONS...THE FORECAST WILL PROBABLY
NEED TO BE CHANGED AS THE EVENT DRAWS CLOSER. BUT AT THIS POINT
FOR THE CITY AND COASTAL SECTIONS IT LOOKS LIKE SNOW AT THE ONSET
AS WET-BULBING WOULD PROBABLY OFFSET ANY BOUNDARY LAYER WARMTH THAT
WOULD OTHERWISE SUPPORT RAINFALL. MIXED RAIN/SLEET/SNOW WOULD THEN
FOLLOW HEADING CLOSER TOWARDS MIDNIGHT. A CHANGEOVER TO RAIN WOULD
THEN LIKELY OCCUR DURING THE LATE NIGHT HOURS. FOR INLAND
SPOTS...PRIMARILY SNOW FOR A DECENT PORTION OF THE NIGHT FOLLOWED BY
A WINTRY MIX LATE. A CHANGEOVER TO RAIN PROBABLY OCCURS BY LATE
MORNING FOR MOST INLAND SPOTS. LIGHT SNOW/SLEET ACCUMULATIONS WOULD
BE POSSIBLE...BUT PRIMARILY INLAND. WHATEVER LITTLE ACCUMULATION THE
CITY/COAST COULD MANAGE WOULD BE WASHED AWAY FAIRLY QUICKLY BY RAIN
AND WARMING TEMPS.
THE SYSTEM HEADS OUT TO SEA ON MONDAY NIGHT WITH A CHANCE OF
LINGERING PCPN THROUGH TUESDAY MORNING AS MODELS HINT AT A WEAK
WAVE OF LOW PRESSURE FORMING ALONG A FRONTAL BOUNDARY TO THE SOUTH
AND KEEPING PCPN CLOSE TO US. SHOULD THERE STILL BE PCPN DURING
THIS PERIOD...IT WOULD LIKELY BE RAIN CHANGING OVER TO A WINTRY
MIX...WITH THE CHANGE FIRST OCCURRING INLAND MONDAY NIGHT...THEN FOR
COASTAL SECTIONS LATE AT NIGHT INTO TUESDAY MORNING.
HIGH PRESSURE BUILDS IN FOR TUESDAY NIGHT THROUGH THURSDAY WITH DRY
WEATHER...BUT WITH COLDER THAN NORMAL TEMPERATURES.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
COLD FRONT NOW EAST OF THE TERMINALS CONTINUES TO DEPART.
BRIEF PERIOD OF IFR CIGS THROUGH 15-16Z...OTHERWISE...CIGS RANGING
FROM 2500-3500 FT. LINGERING RAIN MOVING THROUGH THE REGION WILL
GENERALLY RESULT IN MVFR VSBY AT WORST.
IFR TNGT WITH RAIN. GRADUAL MIXING WITH SLEET AND SNOW FROM NW TO
SE. ALL RAIN AT THE CITY TERMINALS THRU 6Z...WITH SOME MIXING
POSSIBLE BY 12Z. PROB IS TO LOW ATTM TO INCLUDE IN THE TAFS.
LGT SLY FLOW AHEAD OF THE FRONT...WITH WINDS NW BEHIND. GUSTS UP
TO 20KT.
...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: OCNL GUSTS TO 20 KT THRU 16Z.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH IMPLIES
SLANT RANGE VISIBILITY 4-6SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z.
KLGA FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z.
KTEB FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z.
KHPN FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z.
KISP FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 17Z.
.OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY...
.SAT...BECOMING VFR BY AFTN. NW WIND 10-20KT.
.SUN...VFR. LGT WIND.
.SUN NGT...MVFR OR LOWER. SNOW/SLEET/FZRA INTERIOR.
SNOW/SLEET/RAIN COAST.
.MON...IFR. RA. SE WND 15-25KT BECOMING SW IN AFTN.
.TUE...VFR. W WIND 15-25KT.
&&
.MARINE...
THE COLD FRONT MOVE SOUTH OF THE OCEAN COASTAL WATERS.
OVERALL...WINDS BELOW SCA CRITERIA...BUT OCEAN WAVES WILL TAKE A
WHILE TO SUBSIDE. OVERNIGHT...WINDS MAY INCREASE SLIGHTLY FOR A
SHORT TIME LATE AS A WAVE OF LOW PRESSURE PASSES JUST TO THE
SOUTH. WAVES ON THE OCEAN SHOULD SUBSIDE TO JUST BELOW SCA LEVELS.
SCA CONDITIONS ARE POSSIBLE SATURDAY NIGHT OVER THE OCEAN
WATERS...OTHERWISE TRANQUIL. WINDS AND SEAS INCREASE WITH AN
APPROACHING STORM SUNDAY NIGHT AND MONDAY. SCA CONDITIONS EXPECTED
WITH THIS STORM.
&&
.HYDROLOGY...
PRECIPITATION THROUGH SATURDAY IS EXPECTED TO TOTAL AROUND AN
INCH...WITH MOSTLY RAIN EXPECTED. FLOODING IS NOT EXPECTED.
A STORM SYSTEM COULD BRING A LIQUID EQUIVALENT PRECIPITATION AMOUNT
OF A HALF INCH TO AN INCH FROM LATE SUNDAY AFTERNOON THROUGH MONDAY
NIGHT.
&&
.EQUIPMENT...
DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD
EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS
WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL
WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES
TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM.
DURING THIS 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 TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE
INTERFERENCE ISSUE HAS BEEN RESOLVED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ350-
353-355.
&&
$$
SYNOPSIS...JC/PW
NEAR TERM...TONGUE/PW
SHORT TERM...TONGUE/PW
LONG TERM...JC
AVIATION...JMC
MARINE...JC/PW
HYDROLOGY...JC/PW
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS DES MOINES IA
541 AM CST FRI DEC 6 2013
.SHORT TERM /TODAY/...
ISSUED AT 347 AM CST FRI DEC 6 2013
PRIMARY CONCERN TODAY WILL BE TEMP AND WIND CHILL TRENDS. STRONG
CENTRAL PLAINS TO GREAT LAKES JET...08Z RAP MAX WIND OBJECTIVELY
ANALYZED AT 180KTS OVER SRN WI...IS IN PLACE BUT MUCH OF THE
ASSOCIATED FORCING AND RESULTANT SENSIBLE WEATHER IS WELL TO OUR
SOUTH. A FEW WEAK SHORT WAVES WITH MID LEVEL KINEMATIC FORCING ARE
RIDING THE JET BUT WITH LIMITED MOISTURE ARE PRODUCING NOTHING MORE
THAN MID CLOUDS AND LIGHT SNOW ALOFT SO FORECAST REMAINS DRY.
RECENT RAP/NAM RUNS SEEM TO HAVE A BETTER HANDLE ON THIS ARCTIC
AIRMASS THAN THE GFS...AND ARE ALSO SUPPORTED BY HI RES NMM AND
HOPWRF RUNS. THIS THINKING WOULD SUGGEST HIGHS ONLY MAKING THE MID
SINGLE DIGITS NW TO MID TEENS SE TODAY. WINDS WILL CHANGE LITTLE
TODAY...REMAINING STEADY FROM THE NW AROUND 10KTS PLUS...KEEPING
WIND CHILLS AT OR BELOW ADVISORY CRITERIA /-20F/ THROUGH MUCH OF THE
MORNING. NO CHANGES TO EXISTING HEADLINE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 347 AM CST FRI DEC 6 2013
TONIGHT THROUGH SATURDAY WILL BE RELATIVELY QUIET WITH RESPECT TO
PRECIPITATION BUT IT WILL BE VERY COLD. THE ARCTIC HIGH WILL PUSH
SOUTH AND EAST ACROSS THE AREA THROUGH THIS TIME. THE GRADIENT
WILL RELAX ACROSS IOWA SO THE WIND WILL DIMINISH SOME THROUGH THIS
EVENING BUT WITH CLEAR SKIES TEMPERATURES WILL QUICKLY FALL.
ANOTHER WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR TONIGHT BUT
TO AVOID CONFUSION OVER ADDITIONAL HEADLINES I LEFT THAT DECISION
FOR THE DAY SHIFT. NONETHELESS IT WILL REMAIN COLD.
ATTENTION THEN TURNS TO THE SYSTEM COMING IN FOR SUNDAY. A DEEP
UPPER LEVEL TROUGH OVER THE WEST WILL SHIFT INTO THE PLAINS
SATURDAY NIGHT THEN ACROSS THE UPPER MIDWEST SUNDAY AND SUNDAY
NIGHT. AT THE SURFACE A LOW WILL SWING OUT OF THE SOUTHWEST INTO
NORTHERN MISSOURI THEN NORTH CENTRAL ILLINOIS SUNDAY EVENING.
THERE WILL BE SEVERAL WAVES MOVE ACROSS IOWA DURING THIS TIME SO
IT LOOKS AS THOUGH SOME LIGHT SNOW WILL BE POSSIBLE LATE SATURDAY
NIGHT WITH THE FIRST WAVE OF THETA-E ADVECTION THEN AS THE PIECES
OF ENERGY COME ACROSS IOWA SUNDAY THERE WILL BE GENERALLY A LIGHT
TO MODERATE SNOWFALL WITH PERIODS OF MODERATE SNOWFALL. THE LAST
COUPLE OF DAYS THE MODELS HAVE BEEN SUGGESTING A 2 TO 5 INCH SNOW
FALL ACROSS CENTRAL IOWA WITH 2 INCHES ACROSS THE SOUTHEAST AND 5
ACROSS THE FAR NORTHWEST AND WEST. SNOW TO LIQUID RATIONS CONTINUE
TO BE FROM 15 TO 25 TO 1 SO IT WILL NOT TAKE MUCH QPF TO GET
MEASURABLE SNOW. THERE IS STILL SOME UNCERTAINTIES IN THE FINER
DETAILS WHICH WILL PRECLUDE ANY HEADLINES AT THIS TIME BUT WE WILL
CONTINUE TO MONITOR TRENDS.
THE SYSTEM WILL DEPART EARLY MONDAY THEN ANOTHER BLAST OF COLD AIR
WILL COME LATE MONDAY AND TUESDAY USHERED IN BY SOME STRONG WIND.
HOWEVER WITH THE FRESH SNOW FROM SUNDAY...THE WIND MAY CREATE SOME
ISSUES WITH VISIBILITY. WE WILL BE MONITORING THAT AS WELL BUT
WILL GET A BETTER HANDLE ON THAT ONCE WE SEE WHERE THE HEAVIEST
SNOW FALLS. TEMPS MAY MODERATE SOME BY LATE IN THE EXTENDED BUT I
AM NOT PUTTING MUCH WEIGHT IN THAT AS THIS IS DAY 6 AND 7 AND WE
ARE GOING TO HAVE SNOW ON THE GROUND WHICH WILL DEFINITELY IMPACT
TEMPS.
&&
.AVIATION...06/12Z
ISSUED AT 541 AM CST FRI DEC 6 2013
VFR CONDITIONS ANTICIPATED THROUGH THE PERIOD. MOSTLY CLEAR NORTH
WITH MID CLOUD CIGS THROUGHOUT THE DAY SOUTHEAST. NW WINDS WILL
REMAIN STEADY AND CHANGE LITTLE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR CALHOUN-CERRO GORDO-
EMMET-HANCOCK-HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC-
WINNEBAGO-WORTH.
&&
$$
SHORT TERM...SMALL
LONG TERM...FAB
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS DES MOINES IA
407 AM CST FRI DEC 6 2013
.SHORT TERM /TODAY/...
ISSUED AT 347 AM CST FRI DEC 6 2013
PRIMARY CONCERN TODAY WILL BE TEMP AND WIND CHILL TRENDS. STRONG
CENTRAL PLAINS TO GREAT LAKES JET...08Z RAP MAX WIND OBJECTIVELY
ANALYZED AT 180KTS OVER SRN WI...IS IN PLACE BUT MUCH OF THE
ASSOCIATED FORCING AND RESULTANT SENSIBLE WEATHER IS WELL TO OUR
SOUTH. A FEW WEAK SHORT WAVES WITH MID LEVEL KINEMATIC FORCING ARE
RIDING THE JET BUT WITH LIMITED MOISTURE ARE PRODUCING NOTHING MORE
THAN MID CLOUDS AND LIGHT SNOW ALOFT SO FORECAST REMAINS DRY.
RECENT RAP/NAM RUNS SEEM TO HAVE A BETTER HANDLE ON THIS ARCTIC
AIRMASS THAN THE GFS...AND ARE ALSO SUPPORTED BY HI RES NMM AND
HOPWRF RUNS. THIS THINKING WOULD SUGGEST HIGHS ONLY MAKING THE MID
SINGLE DIGITS NW TO MID TEENS SE TODAY. WINDS WILL CHANGE LITTLE
TODAY...REMAINING STEADY FROM THE NW AROUND 10KTS PLUS...KEEPING
WIND CHILLS AT OR BELOW ADVISORY CRITERIA /-20F/ THROUGH MUCH OF THE
MORNING. NO CHANGES TO EXISTING HEADLINE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 347 AM CST FRI DEC 6 2013
TONIGHT THROUGH SATURDAY WILL BE RELATIVELY QUIET WITH RESPECT TO
PRECIPITATION BUT IT WILL BE VERY COLD. THE ARCTIC HIGH WILL PUSH
SOUTH AND EAST ACROSS THE AREA THROUGH THIS TIME. THE GRADIENT
WILL RELAX ACROSS IOWA SO THE WIND WILL DIMINISH SOME THROUGH THIS
EVENING BUT WITH CLEAR SKIES TEMPERATURES WILL QUICKLY FALL.
ANOTHER WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR TONIGHT BUT
TO AVOID CONFUSION OVER ADDITIONAL HEADLINES I LEFT THAT DECISION
FOR THE DAY SHIFT. NONETHELESS IT WILL REMAIN COLD.
ATTENTION THEN TURNS TO THE SYSTEM COMING IN FOR SUNDAY. A DEEP
UPPER LEVEL TROUGH OVER THE WEST WILL SHIFT INTO THE PLAINS
SATURDAY NIGHT THEN ACROSS THE UPPER MIDWEST SUNDAY AND SUNDAY
NIGHT. AT THE SURFACE A LOW WILL SWING OUT OF THE SOUTHWEST INTO
NORTHERN MISSOURI THEN NORTH CENTRAL ILLINOIS SUNDAY EVENING.
THERE WILL BE SEVERAL WAVES MOVE ACROSS IOWA DURING THIS TIME SO
IT LOOKS AS THOUGH SOME LIGHT SNOW WILL BE POSSIBLE LATE SATURDAY
NIGHT WITH THE FIRST WAVE OF THETA-E ADVECTION THEN AS THE PIECES
OF ENERGY COME ACROSS IOWA SUNDAY THERE WILL BE GENERALLY A LIGHT
TO MODERATE SNOWFALL WITH PERIODS OF MODERATE SNOWFALL. THE LAST
COUPLE OF DAYS THE MODELS HAVE BEEN SUGGESTING A 2 TO 5 INCH SNOW
FALL ACROSS CENTRAL IOWA WITH 2 INCHES ACROSS THE SOUTHEAST AND 5
ACROSS THE FAR NORTHWEST AND WEST. SNOW TO LIQUID RATIONS CONTINUE
TO BE FROM 15 TO 25 TO 1 SO IT WILL NOT TAKE MUCH QPF TO GET
MEASURABLE SNOW. THERE IS STILL SOME UNCERTAINTIES IN THE FINER
DETAILS WHICH WILL PRECLUDE ANY HEADLINES AT THIS TIME BUT WE WILL
CONTINUE TO MONITOR TRENDS.
THE SYSTEM WILL DEPART EARLY MONDAY THEN ANOTHER BLAST OF COLD AIR
WILL COME LATE MONDAY AND TUESDAY USHERED IN BY SOME STRONG WIND.
HOWEVER WITH THE FRESH SNOW FROM SUNDAY...THE WIND MAY CREATE SOME
ISSUES WITH VISIBILITY. WE WILL BE MONITORING THAT AS WELL BUT
WILL GET A BETTER HANDLE ON THAT ONCE WE SEE WHERE THE HEAVIEST
SNOW FALLS. TEMPS MAY MODERATE SOME BY LATE IN THE EXTENDED BUT I
AM NOT PUTTING MUCH WEIGHT IN THAT AS THIS IS DAY 6 AND 7 AND WE
ARE GOING TO HAVE SNOW ON THE GROUND WHICH WILL DEFINITELY IMPACT
TEMPS.
&&
.AVIATION...06/06Z
ISSUED AT 1129 PM CST THU DEC 5 2013
VFR CONDITIONS WITH BREEZY NORTHWEST WINDS WILL PERSIST THROUGH
THE PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR CALHOUN-CERRO GORDO-
EMMET-HANCOCK-HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC-
WINNEBAGO-WORTH.
&&
$$
SHORT TERM...SMALL
LONG TERM...FAB
AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1019 AM EST Fri Dec 6 2013
...Forecast Update...
Issued at 1010 AM EST Fri Dec 6 2013
Made some minor tweaks to the grids this morning to better define
sleet/freezing rain/plain rain areas. This didn`t result in any
major changes so our winter weather headlines will stay in the same
areas for now. However, the changes did give Butler/Nelson
counties a bit more freezing rain based on an ice glaze from
freezing rain already reported in Butler County this morning and
current sfc temp gradient orientation.
Overall, dual pol CC`s show the melting layer over southern Indiana
through Dubois, Orange, and Washington counties. Just got reports
of a change over from sleet to snow in NW Dubois County which
confirms that freezing level shown by dual pol data.
For the rest of the morning expect mainly sleet/freezing rain over
southern Indiana with a slow change over to all snow occurring from
the NW to SE. North central KY should largely be light freezing
rain with some areas near the Ohio River seeing some sleet by late
morning. The rain/freezing rain line as of 15Z was from roughly
Morgantown, KY to Frankfort, KY. Expect that line to slowing move
ESE through the day as well. Lexington/Bowling Green areas are
still looking to see a change over to freezing rain in the 2-4 pm
time frame.
Of note, with such warm ground temps ahead of this
weather system earlier this week, areas running in the 30-32 degree
range are seeing ice accums mainly on elevated sfcs. Road impacts
are more common where sfc temps are less than 30 degrees.
Issued at 635 AM EST Fri Dec 6 2013
Secondary surge of moisture is building across Missouri and Arkansas
this hour, and latest SPC mesoanalysis has another frontogenetical
band in the area where banding currently is setting up from KBMG to
KCGI. Latest HRRR is close to current thinking for snow numbers
across our region, 6-10" over our far northwest counties and 3-6"
along the river. The southern end of the warning still has freezing
rain to deal with. We have had a few glazing reports across the
current freezing rain area, which still includes KSDF, though the
intensity has slackened. No headline changes coming still, just
expect conditions to worsen later this morning into the afternoon.
Issued at 455 AM EST Fri Dec 6 2013
Active convection well to out south, and closer to the cold front,
appears to be stealing some of our thunder as far the winter precip
goes. Have a very apparent dry slot forming between this convection,
the northern edge of which now is over Lake Cumberland, and the
heavier sleet across southern Indiana. Even the latter band is
starting to wane as moisture is getting cut off from it. The GEM and
SREF both did a better job of handling this break in the precip, but
both fill that gap back in later this morning and into the
afternoon. Have adjusted totals and early pops to account for these
differences. The overall daytime forecast did not change much, so
will not issue a zone update and no changes to the headline products
are expected at this time.
.SHORT TERM (Now through Saturday Night)...
Issued at 330 AM EST Fri Dec 6 2013
...IMPACTFUL WINTER EVENT ONGOING...
Southwest feed of moisture is pumping in plenty of moisture and
working with Arctic air filtering into the region to create a messy
winter precip forecast this morning. Freezing rain line running
roughly from Russellville in Logan county to Etown/Louisville to
Frankfort. Had a band of heavier returns across our northern row of
counties, where sleet is coming down. SPC mesoanalysis earlier
showed a band of 850-700 mb frontogenesis where this band formed,
but that band has spread out now.
Timing for cold air continues to run a bit faster than previously
forecast, so have had to shift freezing rain timing south. Given
timing for precip coming in, that would also mean higher snow totals
over the north, where the deeper cold air will allow for a quicker
transition to snow during the day today. Bumped up the totals across
our northern counties to 6-10 inches, with areas right along the
Ohio River now getting between 2 and 6 inches.
Current headlines still look good. The northern part of the winter
storm warning looks solid for reaching the heavy snow criteria,
whereas the southern part looks like the combination of freezing
rain, sleet, and snow will be the main threat. The advisory area
looks in line for around an inch of snow and/or a tenth to a quarter
inch of freezing rain.
Moisture tap runs out aloft starts to run out this evening.
Soundings show we may have a period of freezing drizzle, as the top
of the saturated layer gets warmer than -10C. Given temperatures
falling quickly, this freezing drizzle combined with already wet
roadways and temperatures well into the 20s will make for continued
dangerous travel conditions overnight.
Highs Saturday will struggle to get into the lower 20s, if that
high, over southern Indiana in the snowpack. Down south, the
freezing mark will be the hard point to reach. The cold temperatures
will set the stage for the next system to come in, read on below.
.LONG TERM (Sunday through Friday)...
Issued at 320 AM EST Fri Dec 6 2013
...SIGNIFICANT WINTRY WEATHER EXPECTED LATE SATURDAY NIGHT AND
SUNDAY ACROSS THE REGION...
...Saturday night through Monday...
Ding, ding! Round two of wintry weather will commence late Saturday
night and through the day Sunday, as our next mid-level southern
stream wave heads northeastward. Precip may begin across southern
Kentucky around midnight, but models seem to rush it in after
midnight. Precipitation types are still a difficult forecast, which
depends on the final snow/sleet/ice totals from this first round of
wintry precip today.
Currently believe surface temperatures will be cold and the depth of
the cold airmass will be sufficiently deep to support mostly snow at
the precipitation onset. The snow could be particularly heavy early
Sunday across portions of southern Indiana and central Kentucky. As
the wave continues to move northeast, warmer air aloft would
eventually overspread the cold lower layer and result in a change
over to perhaps sleet for a very brief period, but freezing rain
would quickly take over and progress northward. Still too difficult
to pin down the snow and freezing rain amounts, but they could
accumulate rapidly before warmer surface air arrives.
Speaking of that, warmer air will work in at the surface across
southern Kentucky in the afternoon, changing freezing rain over to
rain. This too will continue northward into the evening as the wave
shifts northeast. In fact, the warmest temperatures Sunday may very
well occur in the evening as the warmer surface air gets in here. As
the wave departs, colder air rushes back in and will lead to any
leftover precipitation changing back over to snow before ending.
Highs Sunday look to warm to around the freezing mark in areas north
of the Ohio River late in the day, with mid to upper 30s across much
of Kentucky. Lows Sunday night will cool back into the lower 30s.
Highs on Monday are really tough because they will be so dependent
on snow/ice cover. Right now will go with highs in the lower 30s
across the northwest to lower 40s across the southeast.
Monday Night through Thursday...
Will keep a slight chance of light snow over far eastern and
southeastern counties Monday evening as broad shortwave aloft moves
through. Otherwise, weather during this period calms down as flow
aloft becomes less amplified with no noticeable weather systems to
track across our area. This period looks dry, even with a shortwave
trough diving through the Great Lakes Thursday. Any precip
associated with that trough appears to stay north of the area.
Temperatures will be the big story. It will be quite cold with highs
in the 20s across the north and 30s across the south Tuesday through
Thursday, with lows generally in the single digits across the north
and teens across the southern CWA. As mentioned in the previous
forecast, whatever snow cover exists in our north will affect these
numbers.
&&
.HYDROLOGY...
Issued at 315 PM EDT Thu Dec 5 2013
A prolonged period of precipitation will continue into the weekend.
The first system has already dumped up to an inch and another 1 to 2
inches are expected before the precipitation ends Friday night. The
northern portions will see much of this precipitation change over to
freezing or frozen forms. Thus, rises will occur on rivers and
streams but no flooding on major rivers is expected. However,
localized flooding could still occur tonight into Friday.
The second system Saturday night through Sunday could drop an
additional 1 to 2 inches of precipitation is expected over southeast
Kentucky. Again, the precipitation will be a mixture of frozen and
freezing types and will runoff slower than pure rain. This next shot
could trigger some minor flooding on parts of the Green, Licking,
and Salt basins. If so, flooding will extend into next week.
&&
.AVIATION (12Z TAF Update)...
Updated at 640 AM EST Fri Dec 6 2013
There is a bit of a lull in precipitation occurring across the
region as moisture aloft has diminished a bit. This is leading to or
will lead to more of a freezing drizzle and very light sleet
situation for a few hours this morning rather than the steadier
rain. However, our next wave is just southwest of the area and deep
moisture will quickly spread across the region once again.
Precipitation intensity will increase and as the temperature profile
continues to cool, precip type will change through the day. Expect
precip to end this evening and overnight in the form of light
freezing drizzle/light sleet as we once again lose the upper-level
moisture with the system departing. Expect IFR ceilings will be
common now and through the evening before starting to transition to
MVFR toward the end of the TAF period. Visibilities will also
decrease in the heavier precip later today. Winds will continue to
be out of the north at 9-14 knots.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...WINTER STORM WARNING until 1 AM EST /Midnight CST/ Saturday FOR
KYZ023>038.
WINTER WEATHER ADVISORY until 1 AM EST /Midnight CST/ Saturday
FOR KYZ039>043-045>049-053>055-061>063-070>072.
IN...WINTER STORM WARNING until 1 AM EST /Midnight CST/ Saturday FOR
INZ076>079-083-084-089>092.
&&
$$
Update.........AMS
Short Term.....RJS
Long Term......MJP
Hydrology......CMC
Aviation.......RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
641 AM EST Fri Dec 6 2013
...Updated Aviation and Forecast Discussion...
...Forecast Update...
Issued at 635 AM EST Fri Dec 6 2013
Secondary surge of moisture is building across Missouri and Arkansas
this hour, and latest SPC mesoanalysis has another frontogenetical
band in the area where banding currently is setting up from KBMG to
KCGI. Latest HRRR is close to current thinking for snow numbers
across our region, 6-10" over our far northwest counties and 3-6"
along the river. The southern end of the warning still has freezing
rain to deal with. We have had a few glazing reports across the
current freezing rain area, which still includes KSDF, though the
intensity has slackened. No headline changes coming still, just
expect conditions to worsen later this morning into the afternoon.
Issued at 455 AM EST Fri Dec 6 2013
Active convection well to out south, and closer to the cold front,
appears to be stealing some of our thunder as far the winter precip
goes. Have a very apparent dry slot forming between this convection,
the northern edge of which now is over Lake Cumberland, and the
heavier sleet across southern Indiana. Even the latter band is
starting to wane as moisture is getting cut off from it. The GEM and
SREF both did a better job of handling this break in the precip, but
both fill that gap back in later this morning and into the
afternoon. Have adjusted totals and early pops to account for these
differences. The overall daytime forecast did not change much, so
will not issue a zone update and no changes to the headline products
are expected at this time.
.SHORT TERM (Now through Saturday Night)...
Issued at 330 AM EST Fri Dec 6 2013
...IMPACTFUL WINTER EVENT ONGOING...
Southwest feed of moisture is pumping in plenty of moisture and
working with Arctic air filtering into the region to create a messy
winter precip forecast this morning. Freezing rain line running
roughly from Russellville in Logan county to Etown/Louisville to
Frankfort. Had a band of heavier returns across our northern row of
counties, where sleet is coming down. SPC mesoanalysis earlier
showed a band of 850-700 mb frontogenesis where this band formed,
but that band has spread out now.
Timing for cold air continues to run a bit faster than previously
forecast, so have had to shift freezing rain timing south. Given
timing for precip coming in, that would also mean higher snow totals
over the north, where the deeper cold air will allow for a quicker
transition to snow during the day today. Bumped up the totals across
our northern counties to 6-10 inches, with areas right along the
Ohio River now getting between 2 and 6 inches.
Current headlines still look good. The northern part of the winter
storm warning looks solid for reaching the heavy snow criteria,
whereas the southern part looks like the combination of freezing
rain, sleet, and snow will be the main threat. The advisory area
looks in line for around an inch of snow and/or a tenth to a quarter
inch of freezing rain.
Moisture tap runs out aloft starts to run out this evening.
Soundings show we may have a period of freezing drizzle, as the top
of the saturated layer gets warmer than -10C. Given temperatures
falling quickly, this freezing drizzle combined with already wet
roadways and temperatures well into the 20s will make for continued
dangerous travel conditions overnight.
Highs Saturday will struggle to get into the lower 20s, if that
high, over southern Indiana in the snowpack. Down south, the
freezing mark will be the hard point to reach. The cold temperatures
will set the stage for the next system to come in, read on below.
.LONG TERM (Sunday through Friday)...
Issued at 320 AM EST Fri Dec 6 2013
...SIGNIFICANT WINTRY WEATHER EXPECTED LATE SATURDAY NIGHT AND
SUNDAY ACROSS THE REGION...
...Saturday night through Monday...
Ding, ding! Round two of wintry weather will commence late Saturday
night and through the day Sunday, as our next mid-level southern
stream wave heads northeastward. Precip may begin across southern
Kentucky around midnight, but models seem to rush it in after
midnight. Precipitation types are still a difficult forecast, which
depends on the final snow/sleet/ice totals from this first round of
wintry precip today.
Currently believe surface temperatures will be cold and the depth of
the cold airmass will be sufficiently deep to support mostly snow at
the precipitation onset. The snow could be particularly heavy early
Sunday across portions of southern Indiana and central Kentucky. As
the wave continues to move northeast, warmer air aloft would
eventually overspread the cold lower layer and result in a change
over to perhaps sleet for a very brief period, but freezing rain
would quickly take over and progress northward. Still too difficult
to pin down the snow and freezing rain amounts, but they could
accumulate rapidly before warmer surface air arrives.
Speaking of that, warmer air will work in at the surface across
southern Kentucky in the afternoon, changing freezing rain over to
rain. This too will continue northward into the evening as the wave
shifts northeast. In fact, the warmest temperatures Sunday may very
well occur in the evening as the warmer surface air gets in here. As
the wave departs, colder air rushes back in and will lead to any
leftover precipitation changing back over to snow before ending.
Highs Sunday look to warm to around the freezing mark in areas north
of the Ohio River late in the day, with mid to upper 30s across much
of Kentucky. Lows Sunday night will cool back into the lower 30s.
Highs on Monday are really tough because they will be so dependent
on snow/ice cover. Right now will go with highs in the lower 30s
across the northwest to lower 40s across the southeast.
Monday Night through Thursday...
Will keep a slight chance of light snow over far eastern and
southeastern counties Monday evening as broad shortwave aloft moves
through. Otherwise, weather during this period calms down as flow
aloft becomes less amplified with no noticeable weather systems to
track across our area. This period looks dry, even with a shortwave
trough diving through the Great Lakes Thursday. Any precip
associated with that trough appears to stay north of the area.
Temperatures will be the big story. It will be quite cold with highs
in the 20s across the north and 30s across the south Tuesday through
Thursday, with lows generally in the single digits across the north
and teens across the southern CWA. As mentioned in the previous
forecast, whatever snow cover exists in our north will affect these
numbers.
&&
.HYDROLOGY...
Issued at 315 PM EDT Thu Dec 5 2013
A prolonged period of precipitation will continue into the weekend.
The first system has already dumped up to an inch and another 1 to 2
inches are expected before the precipitation ends Friday night. The
northern portions will see much of this precipitation change over to
freezing or frozen forms. Thus, rises will occur on rivers and
streams but no flooding on major rivers is expected. However,
localized flooding could still occur tonight into Friday.
The second system Saturday night through Sunday could drop an
additional 1 to 2 inches of precipitation is expected over southeast
Kentucky. Again, the precipitation will be a mixture of frozen and
freezing types and will runoff slower than pure rain. This next shot
could trigger some minor flooding on parts of the Green, Licking,
and Salt basins. If so, flooding will extend into next week.
&&
.AVIATION (12Z TAF Update)...
Updated at 640 AM EST Fri Dec 6 2013
There is a bit of a lull in precipitation occurring across the
region as moisture aloft has diminished a bit. This is leading to or
will lead to more of a freezing drizzle and very light sleet
situation for a few hours this morning rather than the steadier
rain. However, our next wave is just southwest of the area and deep
moisture will quickly spread across the region once again.
Precipitation intensity will increase and as the temperature profile
continues to cool, precip type will change through the day. Expect
precip to end this evening and overnight in the form of light
freezing drizzle/light sleet as we once again lose the upper-level
moisture with the system departing. Expect IFR ceilings will be
common now and through the evening before starting to transition to
MVFR toward the end of the TAF period. Visibilities will also
decrease in the heavier precip later today. Winds will continue to
be out of the north at 9-14 knots.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...WINTER STORM WARNING until 1 AM EST /Midnight CST/ Saturday FOR
KYZ023>038.
WINTER WEATHER ADVISORY until 1 AM EST /Midnight CST/ Saturday
FOR KYZ039>043-045>049-053>055-061>063-070>072.
IN...WINTER STORM WARNING until 1 AM EST /Midnight CST/ Saturday FOR
INZ076>079-083-084-089>092.
&&
$$
Update.........RJS
Short Term.....RJS
Long Term......MJP
Hydrology......CMC
Aviation.......MJP
AREA FORECAST DISCUSSION...UPDATED
NWS PADUCAH KY
1127 PM CST Thu Dec 5 2013
.UPDATE...
ISSUED AT 1118 PM CST THU DEC 5 2013
Updated the aviation discussion for the 06Z TAF issuance.
UPDATE ISSUED AT 815 PM CST THU DEC 5 2013
Currently making only minor adjustments to snow/sleet locations in
the grids. There are some slight differences between the latest
NAM and RAP soundings with the NAM a tad warmer. Will keep the mix
but move the snow line a bit farther south. Will up snow amounts
in some areas as Du Quoin is already measuring 2 inches.
Over SEMO now getting reports of sleet. CC product from radar
indicating a mix of snow with bursts of sleet. Expect that to
continue for a good portion of the night except for the extreme
southeast 3 or 4 counties where there might be more icing.
There is currently a lull over west Kentucky but we expect this to
fill in slowly as precipitation is increasing to our south. The
RAP and NAM models keeps a general lull over west Kentucky
through about 9z. Models seem to be hinting at the increase in
intensity over the entire area around midday tomorrow.
&&
.SHORT TERM...(This Evening through Saturday)
ISSUED AT 331 PM CST THU DEC 5 2013
The winter storm is a couple of hours earlier than expected, but
the overall evolution has been as expected so far. The
precipitation has quickly transitioned to sleet over much of
southeast Missouri and southern Illinois. Will allow the warning
to continue as is.
The main shift in guidance, led by the 12Z NAM is to hang onto a
very warm layer aloft longer into the event. The southeast corner
of the area may never see much in the way of snow before the
precipitation ends. The forecast has been shift a bit more toward
freezing rain/ice and less sleet and snow over much of west
Kentucky and Missouri Boot Heel region. A half inch of ice is
likely over much of this area, with just an inch or two of sleet
and snow. Over the northern portions of the area the 6-8" swath of
sleet and snow still looks good, and may not be high enough given
some sleet accumulations we have already received this afternoon.
The overall timing remains the same with the precipitation coming
to a rapid end from west to east Friday afternoon.
North winds generally 10 to 15 mph will continue to bring in much
cooler air through the short term period. Single digit temperatures
are expected over much of the area Friday night, and negative wind
chills are now forecast over much of the area Friday night as
well.
.LONG TERM...(Saturday Night through Thursday)
ISSUED AT 331 PM CST THU DEC 5 2013
Models continue to show low pressure over the western Gulf of Mexico
12z Sunday, with an inverted trof extending east of the PAH forecast
area. Models continue to trend a little farther east, which would
lessen amounts across our area. However, this will also keep our
region in colder air, thus indicating a more persistent wintry mix
and less potential for our southeast counties, where the highest QPF
should be, to change to rain on Sunday. Precipitation will spread
northwest across our counties late Saturday night and continue
through the day Sunday. Light amounts of snow, sleet and a little
freezing rain will be possible across southeast Missouri, southern
Illinois and southwest Indiana by the time the precipitation ends
late Sunday afternoon or Sunday evening.
Across west Kentucky, and possibly into extreme southeast Missouri
and extreme southern Illinois, more significant amounts of freezing
rain and sleet are possible. With almost all of the region below
freezing through the entire event, whatever falls will freeze and/or
accumulate. Southern portions of the Pennyrile region of west
Kentucky have the best chance for temperatures to climb above
freezing, but with the best QPF in this area, a tenth to a quarter
inch of ice accumulation will be possible before the temperatures
potentially climb to above freezing. Lesser amounts of ice are
expected across the rest of west Kentucky and adjacent areas.
Overall confidence is not very high right now, due to current models
trends, but fortunately amounts have trended downward from a couple
of days ago. If the GFS pans out, amounts would still be pretty
significant, but ECMWF, NAM and GEM all show higher QPF mainly over
portions of west Kentucky or to our east. Also, how much snow/ice
pack is left from the winter event just getting started across our
region will have an impact on temperatures and potential
accumulations. By late Sunday night the wintry precip, mainly snow
and sleet by that point, should gradually taper off from west to
east, with a return of dry conditions after 12z Monday.
High pressure will build across the Central Plains Monday and slowly
slide east through mid week, centered over the middle Mississippi
valley by 12z Wednesday. Very cold air will settle into our region
for the early part of the work week. Highs Monday will range from
the middle 20s north to the lower 30s south, then only in the 20s
area wide Tuesday. Lows both Monday night and Tuesday night will
range from the middle single digits north to the middle teens
southeast. By Wednesday and Thursday, with plenty of sunshine, high
temperatures will rebound a little, back into the middle 20s to
middle 30s.
&&
.AVIATION...
ISSUED AT 1118 PM CST THU DEC 5 2013
Cigs and/or vsbys at all sites will gradually decrease from MVFR
to IFR by mid period, then back to MVFR toward the end of the
cycle. Snow/sleet at KCGI should change over to all snow around
15Z. Freezing rain/sleet at KPAH/KEVV/KOWB should change over to
snow between 15-18Z. Northerly winds 10-15 mph gusting up to 20
mph should subside somewhat by the end of the period.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING until 6 PM CST Friday FOR ILZ075>078-
080>094.
MO...WINTER STORM WARNING until 6 PM CST Friday FOR MOZ076-086-087-
100-107>112-114.
IN...WINTER STORM WARNING until 6 PM CST Friday FOR INZ081-082-
085>088.
KY...WINTER STORM WARNING until 6 PM CST Friday FOR KYZ001>008-010-
011-013>016-018>020.
WINTER STORM WARNING until 9 PM CST Friday FOR KYZ009-012-017-
021-022.
&&
$$
SHORT TERM...PS
AVIATION...JP
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1008 AM EST FRI DEC 6 2013
.UPDATE...
THE THICK CANOPY OF MID/HIGH CLOUDS AND WEAK LOW LEVEL COLD AIR
ADVECTION THROUGH THE AFTERNOON WILL INHIBIT MUCH IF ANY DIURNAL
RESPONSE. THIS WILL SUPPORT A MINOR DOWNWARD ADJUSTMENT TO TEMPS
THIS AFTERNOON. THE DEPTH OF THE COLD AIR HAS BEEN INCREASING OVER
THE WESTERN GREAT LAKES WHICH IS LEADING TO A BETTER RESPONSE OFF
LAKE MI. THE 12Z DTX SOUNDING SHOWED A DEEP INVERSION BASED NEAR
920MB. THIS SHOULD ALLOW A GOOD DUCT FOR THE WESTWARD EXPANSION OF
LAKE STRATO CU. RAP SOUNDINGS ON BUFKIT SUGGEST SUPERSATURATION
WITH RESPECT TO ICE NEAR THE INVERSION LEVEL. SO IT SHOULD NOT BE
DIFFICULT TO GENERATE SOME FLURRIES FROM THESE LOWER BASED CLOUDS.
THIS WILL BE MORE PROBABLE ACROSS THE SAGINAW VALLEY AND THUMB
GIVEN THE WESTERLY FLOW. FARTHER SOUTH...THE LOW LEVEL FLOW
BECOMES HIGHLY DIVERGENT WHICH MAY KEEP THE LOW CLOUDS CONFINED TO
WRN LOWER MI THROUGH THE AFTERNOON.
&&
.AVIATION...ISSUED 646 AM EST FRI DEC 6 2013
//DISCUSSION...
DESPITE THE SURFACE FRONT PUSHED UP AGAINST THE APPALACHIAN CHAIN...A
GRADUAL SLOPE TO THIS FEATURE PLACES THE MIDLEVEL PORTION OF THE
FRONT OVER SOUTHEASTERN MICHIGAN. THIS BOUNDARY WILL PROVIDE PLENTY
IN THE WAY OF HIGH CLOUD TODAY. A WAVE IS EXPECTED TO RIDE ALONG THE
BOUNDARY REACHING THE AREA VERY LATE IN THE AFTERNOON AND EARLY
EVENING. DRY AIR IN THE LOW LEVELS AND A RELATIVELY HIGH AMOUNT OF
STABILITY WILL MAKE IT DIFFICULT TO SEE ANY PRECIPITATION. THE ONLY
POTENTIAL FOR ANY FLURRIES TO FALL WOULD BE KDTW/KYIP/KDET. BASES
WILL TRY TO LOWER WITH THIS FORCING...REMAINING AT OR ABOVE 4000 FT.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS AT OR BELOW 5000 FT THIS AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 356 AM EST FRI DEC 6 2013
SHORT TERM...TODAY AND TONIGHT
THE WEATHER FOR SOUTHEASTERN MICHIGAN WILL BE INFLUENCED BY A
BAROCLINIC ZONE THAT IS IN PLACE FROM THE EASTERN GREAT LAKES
THROUGH MUCH OF THE OHIO RIVER VALLEY. THE FRONTAL BOUNDARY WILL
BECOME QUASI-STATIONARY TODAY AS THE VERY STRONG...POLAR JET AXIS
OVERHEAD BECOMES FAIRLY STATIC. CHARACTERISTICS OF THE FRONT OFFERED
BY CROSS SECTIONS ARE: 1. GRADUALLY SLOPED 2. A DOUBLE GRADIENT
STRUCTURE AT ROUGHLY 750 MB AND 550 MB.
A WAVE IS EXPECTED TO RIPPLE ALONG THE BAROCLINIC ZONE LATE THIS
AFTERNOON AS A LOWER TROPOSPHERIC REFLECTION OF RIGHT ENTRANCE
REGION DYNAMICS. OVERALL PRECIPITATION CHANCES WILL BE NEAR ZERO FOR
MUCH OF THE CWA WITH CHANCES VERY LOW ACROSS MONROE COUNTY. THE
REASON IS ANALYSES OF LOW TO MID TROPOSPHERIC -DIV AND DEFORMATION
ADVERTISE VERY LITTLE FORCING. IN ADDITION...CROSS SECTIONS SUPPORT
SUBSIDENCE THIS AFTERNOON BETWEEN THE 750 MB AND 550 MB GRADIENTS
ALONG WITH RELATIVELY HIGH STATIC STABILITY THROUGH A GOOD CHUNK OF
THE COLUMN. A DRY LAYER BELOW THE 750MB GRADIENT WILL PROVIDE AN
EVAPORATION BUFFER. IN THE SPIRIT OF CONTINUITY...CONTINUED TO
INCLUDE A LOW CHANCE POP OF LIGHT SNOW FOR MONROE COUNTY BETWEEN
21-02Z BUT ANY SNOWFALL...IF ANY...WILL BE NEGLIGIBLE. SOME FORCING
VERY HIGH IN COLUMN IS STILL EXPECTED TO OVERLAP SOUTHEASTERN
MICHIGAN WHICH SHOULD PROVIDE AN ABUNDANCE OF HIGH CLOUD FOR MUCH OF
THE DAYLIGHT HOURS.
SLUGGISH MOVEMENT OF THE FRONT TODAY WILL GIVE SOME POTENTIAL AT
AFTERNOON HIGHS DESPITE THE CLOUDS. FREEZING MARK SOUTH...TO MIDDLE
20S NORTH. WIND CHILLS WILL DROP INTO THE TEENS THIS MORNING...THEN
STRUGGLE TO CLIMB ABOVE 20 FOR THE AFTERNOON. SUBSIDENCE OCCURRING
BEHIND THE WAVE LATE TONIGHT ALONG WITH DRY AIR SHOULD ALLOW CLOUDS
TO SCATTER AN HOUR OR TWO BEFORE SUNRISE. TEMPERATURES WILL HAVE THE
POTENTIAL TO DROP...LOWS IN THE TEENS WIND CHILLS IN THE SINGLE
DIGITS FOR ALL OF SOUTHEASTERN MICHIGAN.
LONG TERM...SATURDAY THROUGH THURSDAY
HIGH AMPLITUDE MID LEVEL FLOW ANCHORED BY A SPRAWLING LONGWAVE
TROUGH WILL REMAIN THE CONTROLLING LARGE SCALE FEATURE WELL INTO
NEXT WEEK. THE WEEKEND BEGINS WITH SE MICHIGAN INITIALLY RESIDING
ALONG THE EASTERN EXTENSION OF THE MAIN HEIGHT FALL CENTER AND WELL
WITHIN THE COLD DOME PERPETUATED BY AN INBOUND 1040 MB ARCTIC HIGH.
AMBIENT AIRMASS WILL CARRY A DEEP DRY LAYER ABOVE 900 MB...WHILE A
CHECK OF UPSTREAM SOUNDINGS ACROSS LAKE MICHIGAN SHOW A PROFILE ALSO
LACKING IN MOISTURE DEPTH WITH SUPPRESSED INVERSION HEIGHTS. THIS
WOULD INDICATE THE OPPORTUNITY FOR A LAKE AND/OR DIURNALLY ENHANCED
STRATOCU FIELD WILL BE LIMITED. SOME LINGERING EARLY STRATUS MAY
EXIST...PARTICULARLY ACROSS THE NORTH WITH THE RESIDUAL MOISTURE
SOURCE FROM TODAY PERHAPS SLOWER TO MIX OUT. MAIN STORY WILL BE
TEMPERATURES...WITH EVEN A HIGH DEGREE OF INSOLATION STRUGGLING TO
MODERATE A THERMAL PROFILE CARRYING 925 MB TEMPERATURES IN THE -11
TO -12C RANGE. THIS WILL TRANSLATE INTO HIGHS OF LOWER TO MIDDLE
20S...OR A GOOD 15 DEGREE BELOW EARLY DECEMBER NORMS. THE EXISTING
SURFACE RIDGING AND DEEP DRY LAYER WILL PROMOTE A GOOD RADIATIONAL
COOLING RESPONSE SATURDAY NIGHT. A GRADUALLY INCREASING CIRRUS
SHIELD WILL BE THE ONE POSSIBLE DISRUPTION TO REALIZING THE FULL
POTENTIAL. OVERALL STILL LOOKING AT LOWS IN THE TEENS...A FEW
SINGLE DIGIT READINGS NOT OUT OF THE QUESTION IN THE COLDEST
LOCALES.
CONDITIONS INTO SUNDAY REMAIN DEFINED BY THE PRESENCE OF A COLD/DRY
ENVIRONMENT...LOW LEVEL FLOW FLIPPING TO EASTERLY WITH THE ARCTIC
HIGH SLOWLY EASING EASTWARD. HIGHS AGAIN IN THE 20S...EFFECTIVELY
CONTAINED BY A MORE CONCERTED INCREASE IN HIGH CLOUD. FOCUS INTO
SUNDAY EVENING/NIGHT THEN TURNS TO A WELL DEFINED PV ANOMALY WORKING
THROUGH THE TROUGH BASE. THIS WAVE WILL SHEAR INTO THE PREVAILING
SOUTHWESTERLIES ORIENTED FROM THE CENTRAL PLAINS INTO THE GREAT
LAKES THROUGH THE LATTER HALF OF THE WEEKEND. THIS PROCESS WILL
PROMPT TWO AREAS OF FOCUS...ONE WITHIN A WING OF EMERGING ISENTROPIC
ASCENT AND MOISTURE TRANSPORT ORIGINATING OUT OF THE WESTERN
GULF...AND A SECOND ACCOMPANYING THE PRIMARY REGION OF FORCED ASCENT
CONTAINED WITHIN THE MAIN HEIGHT FALL CENTER AND ALONG THE
DEVELOPING WEAK SURFACE WAVE AND FRONTAL CIRCULATION EJECTING OUT OF
THE PLAINS. THE OVERALL UPPER JET POSITIONING WOULD TEND TO DIRECT
THE BULK OF THE GULF ORIGINATING MOISTURE AND ATTENDANT WEAK ASCENT
TO OUR SOUTHEAST. IT REMAINS PLAUSIBLE FOR SOUTHERN SECTIONS OF
SOUTHEAST MICHIGAN TO RECEIVE A GLANCING SHOT ALONG THE WESTERN EDGE
SUNDAY EVENING. WEAK SURFACE WAVE THEN LIFTS THROUGH LOWER MICHIGAN
SUNDAY NIGHT...DISPLACED SOUTHEAST OF THE MAIN STRIPE OF DCVA AND
DEFORMATION FORCING SHIFTING FROM THE UPPER MS VALLEY INTO THE U.P.
THIS WILL LEAVE SE MICHIGAN UNDER A BROADER LOOKING PERIOD OF
FORCING...STILL SUFFICIENT TOWARD GENERATING A FEW HUNDREDTHS OF QPF
SUNDAY NIGHT. A SUB-FREEZING THERMAL PROFILE THROUGHOUT WILL
SUPPORT ALL SNOW...ALTHOUGH THE PROFILE WILL BE WARMING WITH
TIME...EFFECTIVELY REDUCING POTENTIAL SNOWFALL RATIOS.
A GENERAL EASTWARD MIGRATION OF THE MEAN LONGWAVE TROUGH WILL DIRECT
A SERIES SHORTWAVES OF SIBERIAN ORIGIN THROUGH THE GREAT LAKES
DURING THE EARLY AND MID WEEK PERIOD. THIS WILL RESULT IN AN
EXTENDED STRETCH OF WELL BELOW NORMAL TEMPERATURES AS ARCTIC AIR
TAKES FIRM RESIDENCE THROUGHOUT THE WEEK.
MARINE...
WESTERLY WINDS WILL DIMINISH SLIGHTLY TODAY AND TONIGHT AS THE
PRESSURE GRADIENT EASES BEHIND LOW PRESSURE LIFTING INTO QUEBEC.
THIS WILL RESULT IN A LOWER WAVE CONDITIONS THROUGH THIS TIME.
COLDER AIR MOVING ACROSS THE WATERS WILL MAINTAIN WIND SPEEDS IN
THE 15 TO 20 KNOT RANGE ACROSS NORTHERN PORTIONS OF LAKE HURON.
SLIGHT INCREASE IN WINDS EARLY SATURDAY WILL BRING GUSTS JUST SHY
OF GALES ACROSS NORTHERN LAKE HURON. STRONG HIGH PRESSURE WILL
THEN TAKE CONTROL SATURDAY NIGHT AND SUNDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......SC
AVIATION.....CB
SHORT TERM...CB
LONG TERM....MR
MARINE.......MR
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
658 AM EST FRI DEC 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE TODAY AS A COLD FRONT APPROACHES
FROM THE WEST TONIGHT AND WILL CROSS THE REGION ON SATURDAY AFTERNOON.
A STRONGER COLD FRONT WILL CROSS THE REGION TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 655 AM FRIDAY...TEMPERATURES HAVE REMAINED IN THE MID 60S TO
AROUND 70 THIS MORNING GIVEN A SOUTHWEST WINDS AT 7 TO 11 KNOTS. GIVEN
THIS WARM START...MAXIMUM TEMPERATURES TODAY SHOULD BE ABLE TO
REACH THE UPPER 70S TO LOW 80S WELL INLAND WITH LOW TO MID 70S
ALONG THE IMMEDIATE COAST. THINK RECORD LOWS MAY BE THREATENED AT
LOCATIONS SUCH AS GREENVILLE AND PERHAPS KINSTON LATER
TODAY...DESPITE FAIRLY THICK MID AND HIGH LEVEL CLOUDINESS. LATEST
HIGH RESOLUTION WRF AND RAP MODELS KEEP PRECIPITATION TO THE WEST
AND NORTH OF THE CWA TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
AS OF 325 AM FRIDAY...COLD FRONT WILL APPROACH THE REGION FROM THE
WEST LATER TODAY. BEST LOW-LEVEL MOISTURE TRANSPORT DOES NOT
ARRIVE IN OUR NORTHERN COUNTIES UNTIL AFTER MIDNIGHT AND WILL
SLOWLY RAMP POPS UP WITH CHANCE THRU THE LATE EVENING TO LIKELY
OVER NORTHERN COUNTIES BY LATE TONIGHT. QPF TOTALS THROUGH TONIGHT
DO NOT LOOK TO BE PARTICULARLY HEAVY...GENERALLY AT ONE-TENTH OF
AN INCH OR LESS. TEMPERATURES WILL VERY FROM THE MID TO UPPER 50S
ALONG THE FRONT OVER THE NORTHERN COUNTIES...TO THE MILD LOW AND
MID 60S AHEAD OF THE FRONT OVER THE SOUTHERN TWO-THIRDS OF THE
COUNTY WARNING AREA.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 330 AM FRI...MODELS CONTINUE IN GOOD AGREEMENT ON PUSHING A
SURFACE COLD FRONT THROUGH EASTERN NC SAT MORNING WITH TEMPS
WARMEST IN THE MORNING AND SLOWLY FALLING THROUGHOUT THE DAY DUE
TO CLOUDS AND PRECIP OVERSPREADING THE REGION FROM NW TO SE. THERE
WILL BE A LARGE GRADIENT BETWEEN HEIGHTS/THICKNESSES FROM THE
COASTAL PLAIN COUNTIES TO THE COAST...WITH TEMPS FALLING INTO THE
50S BEHIND THE FRONT. FRONTAL BOUNDARY WILL BE AN ANAFRONT WITH
CLOUD/PRECIP BEHIND THE FRONT. THE UPPER TROUGH WILL REMAIN
CENTERED OVER THE CENTRAL/WESTERN CONUS AS A STRONG RIDGE ALOFT
REMAINS CENTERED OVER FLORIDA...PLACING EASTERN NC IN SW FLOW
ALOFT THROUGH EARLY IN THE WEEK. A STRONG FRONTAL INVERSION WILL
BE PRESENT SAT THROUGH SUN AS 850MB WINDS REMAIN SW WITH NLY
SURFACE WINDS. THIS WILL PRODUCE WIDESPREAD RAIN AND LOW CLOUDS
THROUGH EARLY SUN MORNING. COOLER TEMPS EXPECTED ON SUNDAY DUE TO
CLOUDS/PRECIP WITH HIGHS IN THE 40S INLAND TO 50S ALONG THE COAST.
LATEST GUIDANCE CONTINUES TO INDICATE A COASTAL TROUGH DEVELOPING
SUN AFTERNOON...WHICH BECOMES A WEAK LOW THAT MOVES NNE ALONG THE NC
COAST SUN NIGHT. AS THE LOW MOVES NE OF THE AREA LATE SUN NIGHT/EARLY
MON MORNING...COLD AIR DAMMING SCENARIO WILL SHIFT NW OF THE REGION
AS SW RETURN FLOW TAKES OVER WITH EASTERN NC AGAIN IN THE WARM
SECTOR.
UPPER RIDGE WILL STRENGTHEN AGAIN MON WITH HIGH TEMPS EXPECTED
BACK INTO THE 70S UNDER PARTLY SUNNY SKIES. LOW LEVEL THICKNESSES
BUILD 1385-1390 METERS RANGE...BUT MIXED CLOUDS MAY INHIBIT FULL
INSOLATION SO HELD TEMPS IN THE LOW 70S INLAND TO UPPER 60S
OBX...ALTHOUGH GREATER BREAKS IN CLOUD COVER COULD MEAN TEMPS
REACHING A FEW DEGREES HIGHER THAN CURRENTLY FORECAST.
ANOTHER COLD FRONT WILL PASS THROUGH EASTERN NC EARLY TUES MORNING
BRINGING MORE UNSETTLED WEATHER WITH RAIN AGAIN MOSTLY POST-
FRONTAL AND CONTINUING INTO TUES EVENING BEFORE STRONG HIGH PRESSURE
OVER THE CENTRAL CONUS SHIFTS EAST OVER THE MID-ATLANTIC REGION.
WED/THURS WILL BE DRY AND MUCH COOLER WITH TEMPS STRUGGLING TO
BUILD INTO THE MID 40S DUE TO STRONG COLD AIR ADVECTION IN NLY FLOW.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 655 AM FRIDAY...WITH A LIGHT SOUTHWEST WINDS AT 7 TO 11
KNOTS CONTINUING OVERNIGHT...FOG HAS NOT DEVELOPED AT THE TAF
SITES THIS MORNING. EXTENSIVE MID AND HIGH LEVEL CLOUDINESS WILL
PERSIST THROUGH THE DAY. WINDS GUSTING BETWEEN 15 AND 20 KNOTS ARE
POSSIBLE LATER IN THE DAY IN ADVANCE OF AN APPROACHING COLD FRONT.
NUMERICAL GUIDANCE AGAIN INDICATES PATCHY DENSE FOG LATE TONIGHT...BUT
WITH CONTINUE LIGHT TO MODERATE SW WINDS...AGAIN WILL BE LIMITED
IN SCOPE AND WILL FORECAST JUST MVFR STRATUS AT THIS TIME.
LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 335 AM FRI...A COLD FRONT WILL APPROACH FROM THE NW FRI
NIGHT...MOVING THROUGH THE TERMINALS SAT MORNING. MODEL SOUNDINGS
INDICATE A PROLONGED PERIOD OF MVFR/IFR CONDITIONS EXPECTED TO
DEVELOP LATE FRI NIGHT AND CONTINUE THROUGH MUCH OF SUNDAY...WITH
WIDESPREAD RAIN ALSO DEVELOPING THIS WEEKEND. N/NE WIND GUSTS
15-20KT EXPECTED BEHIND THE FRONT SAT AFTERNOON. A WEAK LOW OFF
THE COAST WILL PUSH NE THROUGH THE AREA SUN NIGHT WITH SW FLOW
TAKING OVER MON WITH PRECIP CHANCES DIMINISHING AND LOWER CIGS
LIFTING N OF THE REGION THOUGH FOG MAY BE A POSSIBILITY AT NIGHT.
ANOTHER COLD FRONT CROSS THE TERMINALS FROM NW TO SE TUES WITH
ANOTHER ROUND OF MVFR/IFR CONDITIONS POSSIBLE IN LOWERED
CEILINGS/VSBYS THROUGH TUES. HIGH PRESSURE BUILDS OVER THE REGION
TUES NIGHT WITH CONDITIONS IMPROVING TO VFR.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 655 AM FRIDAY...BASED ON CURRENT OBSERVATIONAL TRENDS...HAVE
UPPED WINDS TO 15 T0 20 KNOTS ON THE COASTAL WATERS NORTH OF CAPE
LOOKOUT. HAVE ALSO ADDED THE PAMLICO SOUND TO THE SMALL CRAFT
ADVISORY WHICH WILL BEGIN AT 03Z TONIGHT WITH GUSTY SW WINDS
EXPECTED. SEAS REMAIN IN THE 2 TO 3 FOOT RANGE...BUT PER LOCAL
NWPS/SWAN MODEL AND WAVEWATCH GUIDANCE...SEAS WILL BUILD TO AS
HIGH AS 6 FEET BY LATE THIS EVENING AND TONIGHT.
LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 345 AM FRI...SCA CONDITIONS WILL PERSIST OVER THE WATERS
THROUGH THE WEEKEND AS SW WINDS INCREASE TO 20 KT OR HIGHER WITH
SEAS REACHING 6 FT FOR THE OUTER CENTRAL/SOUTHERN WATERS. FRONT
WILL PASS THROUGH THE WATERS BY MIDDAY SAT WITH NORTHERLY CAA
SURGE INCREASING WINDS TO 20 KNOTS WITH SEAS 5-7 FT THROUGH SUN
MORNING. MODELS IN AGREEMENT WITH A WEAK INVERTED/COASTAL TROUGH
OVER THE SOUTHERN/CENTRAL WATERS SUN AFTERNOON WHICH DEVELOPS INTO
A WEAK SURFACE LOW AND MOVES NNE ALONG THE NC COAST SUN NIGHT.
SURFACE WINDS WILL BECOME SW ONCE THE WEAK LOW LIFTS NORTH OF THE
WATERS LATE SUN NIGHT. WINDS AND SEAS BRIEFLY SUBSIDE BELOW SCA
CRITERIA MON MORNING WITH SW WINDS 10-15 KT AND SEAS 3-5 FT...THEN
INCREASE TO 15-20 KT AND SEAS 4-7 FT AS THE GRADIENT TIGHTENS
BETWEEN SURFACE RIDGE OFF THE SOUTHEASTERN COAST AND A COLD FRONT
APPROACHING FROM THE NW. SCA CONDITIONS EXPECTED MON AFTERNOON
LASTING THROUGH AT LEAST TUES. WAVEWATCH III AND LOCAL SWAN/NWPS
IN GOOD AGREEMENT THROUGH THE LONG TERM.
&&
.CLIMATE...
RECORD HIGH (79) WAS SET IN NEW BERN ON THURSDAY AND MORE RECORD
WARMTH LIKELY ON FRIDAY.
BELOW IS A SUMMARY OF THE
CLIMATOLOGICAL RECORD HIGH TEMPERATURES FOR FRIDAY...DECEMBER 6TH:
RECORD HIGH FOR DEC 6:
NEW BERN 81 (1998)
GREENVILLE 80 (1998)
KINSTON 81 (1982)
NEWPORT 77 (1998)
BAYBORO 82 (1998)
MOREHEAD CITY 74 (2011)
WILLIAMSTON 76 (1998)
CAPE HATTERAS 77 (1982)
OCRACOKE 73 (1975)
MANTEO 78 (1998)
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST
SUNDAY FOR AMZ135.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
SUNDAY FOR AMZ150-152-154.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST
SUNDAY FOR AMZ156-158.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...DAG
AVIATION...CTC/DAG
MARINE...CTC/DAG
CLIMATE...CTC
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1056 AM EST FRI DEC 6 2013
.SYNOPSIS...
A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE
TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TODAY THROUGH
SATURDAY...BRINGING A CHANGEOVER TO MIXED AND FROZEN PRECIPITATION
TO THE AREA. HIGH PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE
RECENTLY ACTIVE EARLY SEASON WINTER WEATHER PATTERN ON SATURDAY.
CONFIDENCE IS STEADILY INCREASING FOR A PERIOD OF FROZEN AND
FREEZING PRECIPITATION SUNDAY INTO EARLY MONDAY THAT SHOULD
EVENTUALLY CHANGE TO RAIN. AN ARCTIC FRONTAL PASSAGE EARLY NEXT
WEEK WILL DROP TEMPERATURES WELL BELOW NORMAL THROUGH NEXT
WEDNESDAY.
&&
.NEAR TERM /UNTIL 9 PM THIS EVENING/...
AN ENHANCED AREA OF ENHANCED CLOUDS AND LIGHT RAIN WILL MOVE
ACROSS SOUTHEASTERN PA. A SHALLOW FRONTAL BOUNDARY OVER THE REGION
IS SLOWLY PUSHING COLD AIR IN FROM NORTHWEST TO SOUTH EAST.
TEMPERATURES ARE BELOW FREEZING IN NW PA AND IN THE 40S IN THE
SOUTHEAST. THE 850 MB ZERO ISOTHERM IS IN NW PA. FRONTAL ZONE AT
850 AND A WAVE TO THE WEST WILL PRODUCE SNOW...HEAVY SNOW...SOME
ICE...AND RAIN OVER THE STATE IN THE NEXT 18 HOURS.
THE MAIN PLAYER IS REALLY A LARGE ANTICYCLONE TO THE WEST AND COLD
AIR. THE "STORM" IS REALLY JUST A STRONG FRONTAL ZONE.
THE SREF AND GEFS SUGGEST SNOW WILL MOVE INTO NORTHWESTERN PA THIS
AFTERNOON AND LATER THIS AFTERNOON RAIN WILL MOVE INTO CENTRAL PA.
A SNOW-BAND IS EVOLVING OVER OHIO. THE RAP AND 4KM NAM SUGGEST THE
HEAVIEST SNOW COULD BE A BIT MORE SOUTH THAN THE 16KM SREF AND
55KM GEFS.
THERE SHOULD BE A PERIOD OF MODERATE TO HEAVY SNOW THIS EVENING
AND TO ABOUT MIDNIGHT IN NORTHWESTERN PA. SIGNIFICANT SNOW IS
LIKELY BEFORE 9 PM.
IN CENTRAL AREAS THE RAIN WILL RAPIDLY MIX WITH ICE PELLETS AND
FREEZING RAIN THEN TURN TO SNOW. MOST MODELS SHOW THE 0C CONTOUR
RAIN/SNOW LINE PROXY THROUGH STATE COLLEGE ABOUT 5 PM. THIS
FEATURE STALL BETWEEN STATE COLLEGE AND HARRISBURG UNTIL ABOUT
MIDNIGHT.
MOST OF CENTRAL AND NORTHERN PENNSYLVANIA SHOULD SEE SNOW BY 7 PM
WITH SOME MIX OF ICE PELLETS AND FREEZING RAIN FARTHER SOUTH
BEFORE IT TRANSITIONS TO ALL RAIN IN THE LOWER SUSQUEHANNA VALLEY.
SOUTHEASTERN AREAS WILL REMAIN RAIN THIS EVENING.
...KEY POINT IN CENTRAL AND NORTH-CENTRAL PA IS RAPID RAIN TO SNOW
TRANSITION THIS EVENING...
&&
.SHORT TERM /9 PM THIS EVENING THROUGH 6 PM SATURDAY/...
BETWEEN ABOUT 9 PM AND 2 AM THERE WILL BE SOME MODERATE TO HEAVY
SNOW OVER MOST OF CENTRAL AND NORTHERN PENNSYLVANIA. THE SNOW
SHOULD LET UP A FEW HOURS AFTER MIDNIGHT. SREF AND GEFS HAVE
HEAVIER SNOW BAND NORTH OF THE 4KM RAP AND 4KM NAM. WARNINGS MAY
HAVE TO SLIDE SOUTH SHOULD UPDATED SREF/GEFS INDICATE A SIMILAR TREND.
WE WENT WITH THE HIGHER PROBABILITY FORECAST.
RAIN AND SNOW WITH FREEZING RAIN WILL SAG SOUTHWARD. EXTREME
SOUTHEASTERN AREAS LIKE HARRISBURG AND YORK SHOULD REMAIN ALL RAIN
AND MAY END WITH A BRIEF PERIOD OF FZDZ SATURDAY MORNING.
THE MODELS SUGGEST THE PRECIPITATION IS WELL TO OUR EAST A FEW
HOURS EITHER SIDE OF ABOUT 7 AM. SATURDAY WILL BE COLD BUT SHOULD
BE MOSTLY PRECIPITATION FREE.
LEFT SOME POST FRONTAL NW FLOW SNOW SHOWERS IN WESTERN AND
NORTHWESTERN MOUNTAINS SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
...THERE IS THE POTENTIAL FOR SIGNIFICANT FREEZING RAIN LATE
SUNDAY AND EARLY MONDAY IN THE SOUTHWEST MOUNTAINS....
...PREVIOUS DISCUSSION...1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE
OVER THE UPPER MIDWEST SATURDAY WILL MIGRATE EASTWARD INTO THE
NORTHERN MID- ATLANTIC STATES BY SUNDAY MORNING...SETTING THE
STAGE FOR WHAT APPEARS TO BE A CLASSIC OVERRUNNING MIXED PRECIP
EVENT FOR LATER SUNDAY INTO MONDAY.
05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES
INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING
FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS.
THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN
CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES
SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN
NEW ENGLAND.
DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH
THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM
AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A
BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR
ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN
LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS
MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG
AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES
VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY
AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM
ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS
AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION
MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW
INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD
FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE
LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA.
WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE
IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING
ASSUMING MOD-HVY ICING VIA FZRA.
IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE
REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW
NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD
CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW
COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE
INTO SW NY.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
SHOWERS CONTINUE TO STREAM ACROSS SOUTHERN AND CENTRAL PA WITH
LIGHT MIXED PRECIPITATION OVER JST AND BFD. THIS STEADY WAVE OF
RAIN MOVING THROUGH CENTRAL PA AND THE LOWER SUSQ WILL CONTINUE THROUGH
THE MORNING. CIGS FOR MOST TAF SITES HAVE LIFTED TO MVFR...AND
WILL REMAIN AROUND MVFR THROUGH THE MORNING AND EARLY AFTERNOON.
JST CURRENTLY HAS LIFR CIGS AND WILL SEE THESE CONTINUE THROUGH
THE MORNING AND EARLY AFTERNOON BEFORE SLIGHTLY LIFTING. THESE
WILL BE MVFR AND LOWER THROUGH TONIGHT. EXPECT THE MIXED
PRECIPITATION TO SWITCH TO RAIN THROUGH THE AFTERNOON HOURS
BEFORE SWITCHING TO A WINTRY MIX LATE THIS AFTERNOON AND SWITCHING
TO SNOW TONIGHT. EXPECT IFR CIGS AND VSBYS TO CONTINUE TONIGHT
INTO EARLY TOMORROW. MOST TAF SITES SHOULD BEGIN TO CLEAR EARLY
TOMORROW MORNING.
OUTLOOK...
FRI...MVFR IN RAIN SE. IFR IN SNOW/WINTRY MIX NW.
SAT...MVFR SNOW SHOWERS IN THE MOUNTAINS. VFR IN CENTRAL/EASTERN
AREAS.
SUN...REDUCTIONS DEVELOPING WITH APPROACHING STORM THAT WILL BRING
A WINTRY MIX SPREADING SOUTH TO NORTH INTO SUN NIGHT.
MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM EST
SATURDAY FOR PAZ019-024>028-033>035-042-045-046-049>053.
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 AM EST
SATURDAY FOR PAZ004>006-010>012-017-018-037-041.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...GRUMM/STEINBUGL
SHORT TERM...GRUMM/STEINBUGL
LONG TERM...STEINBUGL
AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1251 PM EST FRI DEC 6 2013
.SYNOPSIS...
LOW PRESSURE MOVES EAST ALONG A STALLED FRONT TO OUR SOUTH
OVERNIGHT. COLD HIGH PRESSURE BUILDING IN FOR THE WEEKEND. LOW
PRESSURE APPROACHES SUNDAY NIGHT AND IMPACTS THE NORTHEAST
THROUGH THE FIRST HALF OF NEXT WEEK WITH HIGH PRESSURE BUILDING IN
FOR THE SECOND HALF.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE GOES WATER VAPOR IMAGERY TELLS THE PICTURE WITH A RIVER OF
MOISTURE FROM THE CENTRAL PACIFIC TO NEWFOUNDLAND.
SFC COLD FRONT SEEN ON RADAR AND IN THE OBS APPROACHING OCEAN CITY
AS OF 1630Z. LATEST HRRR AND RADAR CONTINUES TO SUPPORTS LIGHT RA
ENDING FOR A BRIEF PERIOD EARLY THIS AFTERNOON FROM WEST TO EAST
THEN REDEVELOPING THIS AFTERNOON AS WAVE OF WEAK LOW PRESSURE
RIDE ALONG THE FRONT.
TEMPS STEADY UNTIL 3-4 PM...THEN START A SLOW FALL IN THE COLD
ADVECTION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
HAVE ISSUED A WINTER WX ADVISORY FOR ORANGE AND PUTNAM COUNTIES
FOR TONIGHT BASED ON LASTED DATA AND COLLABORATION WITH
SURROUNDING NWS OFFICES.
COLD "NOSE" IN LOW LEVELS AROUND 2-4K FT AGL LAYER WITH TEMPS OF
-3 TO -5 C BY 00Z AT KSWF SEEN IN 12Z NAM SOUNDING. THIS CLEARLY
SUPPORTS SLEET. IN FACT, MODERATE TO OCCASIONALLY HEAVY SLEET.
SLEET ACCUMULATION IN ORANGE MY BE AN INCH OR MORE. ITS TOWARDS 10
TO 11 PM THAT THE COLUMN ALOFT (5-10K FT AGL) COOLS ENOUGH TO
SUPPORT SNOW. SNOW AMOUNTS ON TOP THE SLEET WILL DEPEND ON THE
PRECISE TIMING OF THIS COOLING ALOFT. SEE THE POTENTIAL, BASED ON
SREF PLUMES, FOR SEVERAL INCHES. THINKING THE HIGH END WOULD BE 5
WITH MORE LIKELY THE 1 TO 3 RANGE. HAVE ISSUED THE WSW BASED ON
THE EXPECTED SIGNIFICANT AMOUNT OF SLEET AT THE START EVEN THROUGH
COUNTY AVERAGES ARE BELOW THE 3 INCH CRITERIA. IN ADDITION...TEMPS
BELOW FREEZING IN THE ADVISORY AREA WILL MAKE FOR A SIGNIFICANT
IMPACT ON TRAVEL.
WITH THE LOSS OF COLD CLOUD SEEDER/FEEDER NUCLEATION...PCPN IN
THE ADVISORY AREA MY END AS LIGHT FREEZING DRIZZLE.
THE I-84 CORRIDOR IN CT SHOULD ALSO GET ACCUMULATIONS. THUS THESE
AREAS ARE IN THE HWO PRODUCT AND WILL ISSUE AN SPECIAL WEATHER
STATEMENT ONCE RULES ALLOW.
ALONG THE COAST...SEE ALL RAIN. THINK THE POTENTIAL FOR AN SLEET
IS TOO LOW TO MENTION.
EXPECT PCPN TO END QUICKLY SATURDAY AM WITH CLOUDS GIVING WAY TO
AFTERNOON SUNSHINE.
TEMPS RISE TO THE UPPER 30S TO LOWER 40S SATURDAY (GFS MOS
USED)...WHICH IS SLIGHTLY BELOW NORMAL.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE KEEPS THE REGION DRY SATURDAY NIGHT AND MOST OF THE
DAYTIME HOURS OF SUNDAY WITH BELOW-NORMAL TEMPS.
FOR LATE-DAY SUNDAY THROUGH MONDAY NIGHT...MODELS IN GOOD AGREEMENT
THAT LOW PRESSURE SHIFTS IN FROM THE SOUTH AND WEST...BRINGING
PCPN MAINLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON. THERE IS A
CHANCE HOWEVER THAT THE SOUTHERNMOST PORTIONS OF THE FORECAST AREA
SEE SOME LIGHT SNOW OR FLURRIES DEVELOP RIGHT BEFORE SUNSET ON
SUNDAY. PCPN EVENTUALLY BECOMES LIKELY FOR THE CITY AND OTHER
SOUTHERN SECTIONS BY MIDNIGHT...THEN LIKELY FARTHER NORTH AND EAST
AROUND OR SHORTLY AFTER MIDNIGHT.
FORECAST BUFKIT SOUNDINGS SHOW AN ELEVATED WARM LAYER
DEVELOPING...RESULTING IN MIXED PCPN TYPES. COMPLICATING THE
PCPN TYPE FORECAST FURTHER WILL BE COOLING OF BOUNDARY LAYER AND
SURFACE TEMPS DUE TO WET-BULBING...FOLLOWED BY ONSHORE WINDS THAT
WOULD PUSH TEMPS BACK UP OVERNIGHT SUNDAY NIGHT.
DUE TO THE PCPN TYPE COMPLICATIONS...THE FORECAST WILL PROBABLY
NEED TO BE CHANGED AS THE EVENT DRAWS CLOSER. BUT AT THIS POINT
FOR THE CITY AND COASTAL SECTIONS IT LOOKS LIKE SNOW AT THE ONSET
AS WET-BULBING WOULD PROBABLY OFFSET ANY BOUNDARY LAYER WARMTH
THAT WOULD OTHERWISE SUPPORT RAINFALL. MIXED RAIN/SLEET/SNOW WOULD
THEN FOLLOW HEADING CLOSER TOWARDS MIDNIGHT. A CHANGEOVER TO RAIN
WOULD THEN LIKELY OCCUR DURING THE LATE NIGHT HOURS. FOR INLAND
SPOTS...PRIMARILY SNOW FOR A DECENT PORTION OF THE NIGHT FOLLOWED
BY A WINTRY MIX LATE. A CHANGEOVER TO RAIN PROBABLY OCCURS BY LATE
MORNING FOR MOST INLAND SPOTS. LIGHT SNOW/SLEET ACCUMULATIONS
WOULD BE POSSIBLE...BUT PRIMARILY INLAND. WHATEVER LITTLE
ACCUMULATION THE CITY/COAST COULD MANAGE WOULD BE WASHED AWAY
FAIRLY QUICKLY BY RAIN AND WARMING TEMPS.
THE SYSTEM HEADS OUT TO SEA ON MONDAY NIGHT WITH A CHANCE OF
LINGERING PCPN THROUGH TUESDAY MORNING AS MODELS HINT AT A WEAK
WAVE OF LOW PRESSURE FORMING ALONG A FRONTAL BOUNDARY TO THE SOUTH
AND KEEPING PCPN CLOSE TO US. SHOULD THERE STILL BE PCPN DURING
THIS PERIOD...IT WOULD LIKELY BE RAIN CHANGING OVER TO A WINTRY
MIX...WITH THE CHANGE FIRST OCCURRING INLAND MONDAY NIGHT...THEN FOR
COASTAL SECTIONS LATE AT NIGHT INTO TUESDAY MORNING.
HIGH PRESSURE BUILDS IN FOR TUESDAY NIGHT THROUGH THURSDAY WITH DRY
WEATHER...BUT WITH COLDER THAN NORMAL TEMPERATURES.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
MVFR WITH LCL IFR CONDS THIS AFTERNOON IN -RA/BR.
LOW PRES APPROACHES TONIGHT. ALL RAIN AT THE TERMINALS THROUGH
10Z...POSSIBLY MIXING WITH SLEET AS PRECIP WINDS DOWN AROUND 10Z.
FOR KSWF...RAIN CHANGES TO SLEET THIS EVENING...AND THEN
SNOW/SLEET ON TAP FOR MUCH OF TONIGHT BEFORE PRECIP TAPERS OFF AS
SNOW LATE. IFR/LIFR CONDS.
N WINDS AROUND 10 KT...BACKING TO THE NW SATURDAY MORNING. VFR BY
LATE SATURDAY MORNING.
...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: MARGINAL CONDS...LOWERING TO IFR BY 23Z.
KJFK FCSTER COMMENTS: MARGINAL CONDS...LOWERING TO IFR BY 23Z.
KLGA FCSTER COMMENTS: MARGINAL CONDS...LOWERING TO IFR BY 23Z.
KTEB FCSTER COMMENTS: IFR/MVFR CONDS...BCMG IFR BY 23Z.
KHPN FCSTER COMMENTS: IFR/MVFR CONDS...BCMG IFR BY 23Z.
KISP FCSTER COMMENTS: IFR/MVFR CONDS...BCMG IFR BY 00Z.
.OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY...
.SAT AFTERNOON...VFR. NW WINDS 10-20 KT.
.SUNDAY...VFR. LIGHT WINDS.
.SUNDAY NIGHT...IFR. SNOW...THEN SNOW/SLEET/RAIN NEAR THE COAST
AND SNOW/SLEET ACROSS INTERIOR.
.MONDAY...IFR. RAIN. WINTRY MIX ACROSS INTERIOR EARLY...THEN RAIN.
SE WINDS 10-15 KT...BCMG NW LATE.
.MONDAY NIGHT...WINTRY MIX POSSIBLE. WEST WINDS 10 KT OR LESS.
.TUESDAY...VFR. WEST WINDS 10 KT OR LESS.
.WEDNESDAY...VFR. W WIND 15-25 KT.
&&
.MARINE...
COLD FRONT NOW WELL SOUTH OF THE OCEAN COASTAL WATERS.
OVERALL...WINDS BELOW SCA CRITERIA...BUT OCEAN WAVES WILL TAKE A
WHILE TO SUBSIDE. OVERNIGHT...WINDS INCREASE FOR A SHORT TIME
LATE AS A WAVE OF LOW PRESSURE PASSES JUST TO THE SOUTH. WAVES ON
THE OCEAN SHOULD SUBSIDE TO JUST BELOW SCA LEVELS.
SCA CONDITIONS ARE POSSIBLE SATURDAY NIGHT OVER THE OCEAN
WATERS...OTHERWISE TRANQUIL. WINDS AND SEAS INCREASE WITH AN
APPROACHING STORM SUNDAY NIGHT AND MONDAY. SCA CONDITIONS EXPECTED
WITH THIS STORM.
&&
.HYDROLOGY...
PRECIPITATION THROUGH SATURDAY IS EXPECTED TO TOTAL NEAR AN
INCH. NO HYDROLOGIC ISSUES ANTICIPATED.
A STORM SYSTEM COULD BRING A LIQUID EQUIVALENT PRECIPITATION AMOUNT
OF A HALF INCH TO AN INCH FROM LATE SUNDAY AFTERNOON THROUGH MONDAY
NIGHT.
&&
.EQUIPMENT...
DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD
EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS
WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL
WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES
TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM.
DURING THIS 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 TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE
INTERFERENCE ISSUE HAS BEEN RESOLVED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
SATURDAY FOR NYZ067-068.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ350-
353-355.
&&
$$
SYNOPSIS...TONGUE
NEAR TERM...TONGUE
SHORT TERM...TONGUE/PW
LONG TERM...JC
AVIATION...MPS
MARINE...JC/PW
HYDROLOGY...JC/PW
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1200 PM EST FRI DEC 6 2013
.SYNOPSIS...
LOW PRESSURE MOVES EAST ALONG A STALLED FRONT TO OUR SOUTH
OVERNIGHT. COLD HIGH PRESSURE BUILDING IN FOR THE WEEKEND. LOW
PRESSURE APPROACHES SUNDAY NIGHT AND IMPACTS THE NORTHEAST
THROUGH THE FIRST HALF OF NEXT WEEK WITH HIGH PRESSURE BUILDING IN
FOR THE SECOND HALF.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE GOES WATER VAPOR IMAGERY TELLS THE PICTURE WITH A RIVER OF
MOISTURE FROM THE CENTRAL PACIFIC TO NEWFOUNDLAND.
SFC COLD FRONT SEEN ON RADAR AND IN THE OBS APPROACHING OCEAN CITY
AS OF 1630Z. LATEST HRRR AND RADAR CONTINUES TO SUPPORTS LIGHT RA
ENDING FOR A BRIEF PERIOD EARLY THIS AFTERNOON FROM WEST TO EAST
THEN REDEVELOPING THIS AFTERNOON AS WAVE OF WEAK LOW PRESSURE
RIDE ALONG THE FRONT.
TEMPS STEADY UNTIL 3-4 PM...THEN START A SLOW FALL IN THE COLD
ADVECTION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
HAVE ISSUED A WINTER WX ADVISORY FOR ORANGE AND PUTNAM COUNTIES
FOR TONIGHT BASED ON LASTED DATA AND COLLABORATION WITH
SURROUNDING NWS OFFICES.
COLD "NOSE" IN LOW LEVELS AROUND 2-4K FT AGL LAYER WITH TEMPS OF
-3 TO -5 C BY 00Z AT KSWF SEEN IN 12Z NAM SOUNDING. THIS CLEARLY
SUPPORTS SLEET. IN FACT, MODERATE TO OCCASIONALLY HEAVY SLEET.
SLEET ACCUMULATION IN ORANGE MY BE AN INCH OR MORE. ITS TOWARDS 10
TO 11 PM THAT THE COLUMN ALOFT (5-10K FT AGL) COOLS ENOUGH TO
SUPPORT SNOW. SNOW AMOUNTS ON TOP THE SLEET WILL DEPEND ON THE
PRECISE TIMING OF THIS COOLING ALOFT. SEE THE POTENTIAL, BASED ON
SREF PLUMES, FOR SEVERAL INCHES. THINKING THE HIGH END WOULD BE 5
WITH MORE LIKELY THE 1 TO 3 RANGE. HAVE ISSUED THE WSW BASED ON
THE EXPECTED SIGNIFICANT AMOUNT OF SLEET AT THE START EVEN THROUGH
COUNTY AVERAGES ARE BELOW THE 3 INCH CRITERIA. IN ADDITION...TEMPS
BELOW FREEZING IN THE ADVISORY AREA WILL MAKE FOR A SIGNIFICANT
IMPACT ON TRAVEL.
WITH THE LOSS OF COLD CLOUD SEEDER/FEEDER NUCLEATION...PCPN IN
THE ADVISORY AREA MY END AS LIGHT FREEZING DRIZZLE.
THE I-84 CORRIDOR IN CT SHOULD ALSO GET ACCUMULATIONS. THUS THESE
AREAS ARE IN THE HWO PRODUCT AND WILL ISSUE AN SPECIAL WEATHER
STATEMENT ONCE RULES ALLOW.
ALONG THE COAST...SEE ALL RAIN. THINK THE POTENTIAL FOR AN SLEET
IS TOO LOW TO MENTION.
EXPECT PCPN TO END QUICKLY SATURDAY AM WITH CLOUDS GIVING WAY TO
AFTERNOON SUNSHINE.
TEMPS RISE TO THE UPPER 30S TO LOWER 40S SATURDAY (GFS MOS USED)...WHICH
IS SLIGHTLY BELOW NORMAL.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE KEEPS THE REGION DRY SATURDAY NIGHT AND MOST OF THE
DAYTIME HOURS OF SUNDAY WITH BELOW-NORMAL TEMPS.
FOR LATE-DAY SUNDAY THROUGH MONDAY NIGHT...MODELS IN GOOD AGREEMENT
THAT LOW PRESSURE SHIFTS IN FROM THE SOUTH AND WEST...BRINGING
PCPN MAINLY SUNDAY NIGHT THROUGH MONDAY AFTERNOON. THERE IS A
CHANCE HOWEVER THAT THE SOUTHERNMOST PORTIONS OF THE FORECAST AREA
SEE SOME LIGHT SNOW OR FLURRIES DEVELOP RIGHT BEFORE SUNSET ON
SUNDAY. PCPN EVENTUALLY BECOMES LIKELY FOR THE CITY AND OTHER
SOUTHERN SECTIONS BY MIDNIGHT...THEN LIKELY FARTHER NORTH AND EAST
AROUND OR SHORTLY AFTER MIDNIGHT.
FORECAST BUFKIT SOUNDINGS SHOW AN ELEVATED WARM LAYER
DEVELOPING...RESULTING IN MIXED PCPN TYPES. COMPLICATING THE
PCPN TYPE FORECAST FURTHER WILL BE COOLING OF BOUNDARY LAYER AND
SURFACE TEMPS DUE TO WET-BULBING...FOLLOWED BY ONSHORE WINDS THAT
WOULD PUSH TEMPS BACK UP OVERNIGHT SUNDAY NIGHT.
DUE TO THE PCPN TYPE COMPLICATIONS...THE FORECAST WILL PROBABLY
NEED TO BE CHANGED AS THE EVENT DRAWS CLOSER. BUT AT THIS POINT
FOR THE CITY AND COASTAL SECTIONS IT LOOKS LIKE SNOW AT THE ONSET
AS WET-BULBING WOULD PROBABLY OFFSET ANY BOUNDARY LAYER WARMTH THAT
WOULD OTHERWISE SUPPORT RAINFALL. MIXED RAIN/SLEET/SNOW WOULD THEN
FOLLOW HEADING CLOSER TOWARDS MIDNIGHT. A CHANGEOVER TO RAIN WOULD
THEN LIKELY OCCUR DURING THE LATE NIGHT HOURS. FOR INLAND
SPOTS...PRIMARILY SNOW FOR A DECENT PORTION OF THE NIGHT FOLLOWED BY
A WINTRY MIX LATE. A CHANGEOVER TO RAIN PROBABLY OCCURS BY LATE
MORNING FOR MOST INLAND SPOTS. LIGHT SNOW/SLEET ACCUMULATIONS WOULD
BE POSSIBLE...BUT PRIMARILY INLAND. WHATEVER LITTLE ACCUMULATION THE
CITY/COAST COULD MANAGE WOULD BE WASHED AWAY FAIRLY QUICKLY BY RAIN
AND WARMING TEMPS.
THE SYSTEM HEADS OUT TO SEA ON MONDAY NIGHT WITH A CHANCE OF
LINGERING PCPN THROUGH TUESDAY MORNING AS MODELS HINT AT A WEAK
WAVE OF LOW PRESSURE FORMING ALONG A FRONTAL BOUNDARY TO THE SOUTH
AND KEEPING PCPN CLOSE TO US. SHOULD THERE STILL BE PCPN DURING
THIS PERIOD...IT WOULD LIKELY BE RAIN CHANGING OVER TO A WINTRY
MIX...WITH THE CHANGE FIRST OCCURRING INLAND MONDAY NIGHT...THEN FOR
COASTAL SECTIONS LATE AT NIGHT INTO TUESDAY MORNING.
HIGH PRESSURE BUILDS IN FOR TUESDAY NIGHT THROUGH THURSDAY WITH DRY
WEATHER...BUT WITH COLDER THAN NORMAL TEMPERATURES.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
COLD FRONT NOW WELL SOUTHEAST OF LONG ISLAND. MARGINAL CIGS
THIS AFTERNOON WITH RA.
IFR TNGT WITH RAIN. GRADUAL MIXING WITH SLEET AND SNOW FROM NW TO
SE. ALL RAIN AT THE CITY TERMINALS THRU 6Z...WITH SOME MIXING
POSSIBLE BY 12Z. PROB IS TO LOW ATTM TO INCLUDE IN THE TAFS.
LGT SLY FLOW AHEAD OF THE FRONT...WITH WINDS NW BEHIND. GUSTS UP
TO 20KT.
...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: OCNL GUSTS TO 20 KT THRU 16Z.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH IMPLIES
SLANT RANGE VISIBILITY 4-6SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z.
KLGA FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z.
KTEB FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z.
KHPN FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 16Z.
KISP FCSTER COMMENTS: OCNL GUSTS TO 20 KT THRU 17Z.
.OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY...
.SAT...BECOMING VFR BY AFTN. NW WIND 10-20KT.
.SUN...VFR. LGT WIND.
.SUN NGT...MVFR OR LOWER. SNOW/SLEET/FZRA INTERIOR.
SNOW/SLEET/RAIN COAST.
.MON...IFR. RA. SE WND 15-25KT BECOMING SW IN AFTN.
.TUE...VFR. W WIND 15-25KT.
&&
.MARINE...
COLD FRONT NOW WELL SOUTH OF THE OCEAN COASTAL WATERS.
OVERALL...WINDS BELOW SCA CRITERIA...BUT OCEAN WAVES WILL TAKE A
WHILE TO SUBSIDE. OVERNIGHT...WINDS INCREASE FOR A SHORT TIME
LATE AS A WAVE OF LOW PRESSURE PASSES JUST TO THE SOUTH. WAVES ON
THE OCEAN SHOULD SUBSIDE TO JUST BELOW SCA LEVELS.
SCA CONDITIONS ARE POSSIBLE SATURDAY NIGHT OVER THE OCEAN
WATERS...OTHERWISE TRANQUIL. WINDS AND SEAS INCREASE WITH AN
APPROACHING STORM SUNDAY NIGHT AND MONDAY. SCA CONDITIONS EXPECTED
WITH THIS STORM.
&&
.HYDROLOGY...
PRECIPITATION THROUGH SATURDAY IS EXPECTED TO TOTAL NEAR AN
INCH. NO HYDROLOGIC ISSUES ANTICIPATED.
A STORM SYSTEM COULD BRING A LIQUID EQUIVALENT PRECIPITATION AMOUNT
OF A HALF INCH TO AN INCH FROM LATE SUNDAY AFTERNOON THROUGH MONDAY
NIGHT.
&&
.EQUIPMENT...
DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD
EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS
WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL
WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES
TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM.
DURING THIS 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 TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE
INTERFERENCE ISSUE HAS BEEN RESOLVED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
SATURDAY FOR NYZ067-068.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ350-
353-355.
&&
$$
SYNOPSIS...TONGUE
NEAR TERM...TONGUE
SHORT TERM...TONGUE/PW
LONG TERM...JC
AVIATION...MPS
MARINE...JC/PW
HYDROLOGY...JC/PW
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1128 AM CST FRI DEC 6 2013
.SHORT TERM /TODAY/...
ISSUED AT 347 AM CST FRI DEC 6 2013
PRIMARY CONCERN TODAY WILL BE TEMP AND WIND CHILL TRENDS. STRONG
CENTRAL PLAINS TO GREAT LAKES JET...08Z RAP MAX WIND OBJECTIVELY
ANALYZED AT 180KTS OVER SRN WI...IS IN PLACE BUT MUCH OF THE
ASSOCIATED FORCING AND RESULTANT SENSIBLE WEATHER IS WELL TO OUR
SOUTH. A FEW WEAK SHORT WAVES WITH MID LEVEL KINEMATIC FORCING ARE
RIDING THE JET BUT WITH LIMITED MOISTURE ARE PRODUCING NOTHING MORE
THAN MID CLOUDS AND LIGHT SNOW ALOFT SO FORECAST REMAINS DRY.
RECENT RAP/NAM RUNS SEEM TO HAVE A BETTER HANDLE ON THIS ARCTIC
AIRMASS THAN THE GFS...AND ARE ALSO SUPPORTED BY HI RES NMM AND
HOPWRF RUNS. THIS THINKING WOULD SUGGEST HIGHS ONLY MAKING THE MID
SINGLE DIGITS NW TO MID TEENS SE TODAY. WINDS WILL CHANGE LITTLE
TODAY...REMAINING STEADY FROM THE NW AROUND 10KTS PLUS...KEEPING
WIND CHILLS AT OR BELOW ADVISORY CRITERIA /-20F/ THROUGH MUCH OF THE
MORNING. NO CHANGES TO EXISTING HEADLINE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 347 AM CST FRI DEC 6 2013
TONIGHT THROUGH SATURDAY WILL BE RELATIVELY QUIET WITH RESPECT TO
PRECIPITATION BUT IT WILL BE VERY COLD. THE ARCTIC HIGH WILL PUSH
SOUTH AND EAST ACROSS THE AREA THROUGH THIS TIME. THE GRADIENT
WILL RELAX ACROSS IOWA SO THE WIND WILL DIMINISH SOME THROUGH THIS
EVENING BUT WITH CLEAR SKIES TEMPERATURES WILL QUICKLY FALL.
ANOTHER WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR TONIGHT BUT
TO AVOID CONFUSION OVER ADDITIONAL HEADLINES I LEFT THAT DECISION
FOR THE DAY SHIFT. NONETHELESS IT WILL REMAIN COLD.
ATTENTION THEN TURNS TO THE SYSTEM COMING IN FOR SUNDAY. A DEEP
UPPER LEVEL TROUGH OVER THE WEST WILL SHIFT INTO THE PLAINS
SATURDAY NIGHT THEN ACROSS THE UPPER MIDWEST SUNDAY AND SUNDAY
NIGHT. AT THE SURFACE A LOW WILL SWING OUT OF THE SOUTHWEST INTO
NORTHERN MISSOURI THEN NORTH CENTRAL ILLINOIS SUNDAY EVENING.
THERE WILL BE SEVERAL WAVES MOVE ACROSS IOWA DURING THIS TIME SO
IT LOOKS AS THOUGH SOME LIGHT SNOW WILL BE POSSIBLE LATE SATURDAY
NIGHT WITH THE FIRST WAVE OF THETA-E ADVECTION THEN AS THE PIECES
OF ENERGY COME ACROSS IOWA SUNDAY THERE WILL BE GENERALLY A LIGHT
TO MODERATE SNOWFALL WITH PERIODS OF MODERATE SNOWFALL. THE LAST
COUPLE OF DAYS THE MODELS HAVE BEEN SUGGESTING A 2 TO 5 INCH SNOW
FALL ACROSS CENTRAL IOWA WITH 2 INCHES ACROSS THE SOUTHEAST AND 5
ACROSS THE FAR NORTHWEST AND WEST. SNOW TO LIQUID RATIONS CONTINUE
TO BE FROM 15 TO 25 TO 1 SO IT WILL NOT TAKE MUCH QPF TO GET
MEASURABLE SNOW. THERE IS STILL SOME UNCERTAINTIES IN THE FINER
DETAILS WHICH WILL PRECLUDE ANY HEADLINES AT THIS TIME BUT WE WILL
CONTINUE TO MONITOR TRENDS.
THE SYSTEM WILL DEPART EARLY MONDAY THEN ANOTHER BLAST OF COLD AIR
WILL COME LATE MONDAY AND TUESDAY USHERED IN BY SOME STRONG WIND.
HOWEVER WITH THE FRESH SNOW FROM SUNDAY...THE WIND MAY CREATE SOME
ISSUES WITH VISIBILITY. WE WILL BE MONITORING THAT AS WELL BUT
WILL GET A BETTER HANDLE ON THAT ONCE WE SEE WHERE THE HEAVIEST
SNOW FALLS. TEMPS MAY MODERATE SOME BY LATE IN THE EXTENDED BUT I
AM NOT PUTTING MUCH WEIGHT IN THAT AS THIS IS DAY 6 AND 7 AND WE
ARE GOING TO HAVE SNOW ON THE GROUND WHICH WILL DEFINITELY IMPACT
TEMPS.
&&
.AVIATION...06/18Z
ISSUED AT 1125 AM CST FRI DEC 6 2013
VFR CONDITIONS EXPECTED AT SITES THROUGH PERIOD. WINDS WILL REMAIN
TO THE NORTHWEST AND BECOME LIGHTER AFTER 00Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SMALL
LONG TERM...FAB
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1206 PM CST FRI DEC 6 2013
.AVIATION...THE LEADING EDGE OF THE SHALLOW COLD WEDGE OF A COLD
FRONT IS JUST BEYOND TERMINAL ARA WITH VLIFR CIGS, DRIZZLE AND FOG
EXTENDING BACK INTO ARA AND LFT. TO THE WEST, IFR CIGS WITH A FEW SHOWERS
AROUND LCH. PRECIP MORE EXTENSIVE TO THE NORTH AROUND AEX WHERE
LIFR CIGS COMBINE WITH VIS CURRENTLY LESS THAN 2 MILES IN A
MODERATE BAND OF RAIN AND DRIZZLE WILL SHORTLY BE MOVING EAST WITH
VIS TO 3 MILES IMPROVING TO 6 MILES WHILE LIFR CIGS PERSIST THIS AFTERNOON.
ALL LOCATIONS SHOULD SEE PRECIP ENDING WITH MVFR CIGS AND GUSTY
WINDS THIS EVENING WITH THE EXCEPTION OF ARA WHERE IFR CIGS SHOULD
CONTINUE. A FEW SHOWERS COULD REAPPEAR SATURDAY MORNING AS
ADDITIONAL MOISTURE MOVES IN ALOFT AS A FRONTAL WAVE DEVELOPS NEAR
THE TEXAS COAST.
SWEENEY
&&
.PREV DISCUSSION... /ISSUED 1116 AM CST FRI DEC 6 2013/
DISCUSSION...
CDFNT FAIRLY EVIDENT ON VISIBLE SATELLITE AND RADAR IMAGERY
EXTENDING FROM SOUTH CENTRAL LOUISIANA INTO THE WESTERN
GULF...WITH AN EXTENSIVE BLANKET OF POST FRONTAL STRATUS NOW
COVERING ALL BUT EXTREME SE INLAND ZONES AND THE SE THIRD OR SO OF
THE MAOR. DRIZZLE...ALONG WITH PATCHES OF MODERATE RAIN AND A FEW
SHOWERS...PREVAIL IN THE COLD POST FRONTAL AIRMASS. COVERAGE HAS
INCREASED OVER THE PAST COUPLE OF HOURS OR SO...AND THIS SHOULD
CONTINUE HEADING INTO THE EARLY TO MID AFTERNOON...WITH RAIN
CHANCES STARTING TO DECLINE HEADING FROM LATE AFTERNOON THROUGH
THE EVENING. WITH THE EXCEPTION OF LOCATIONS AHEAD OF THE FRONT
WHERE WARMING IS ONGOING...TEMPERATURES ARE EXPECTED TO REMAIN
STEADY IF NOT FALL SLOWLY THROUGH THE DAY. THE CONTRAST IS
STRIKING...WITH LATEST OBS FROM LAFAYETTE AND PATTERSON REPORTING
49 AND 79 DEGREES RESPECTIVELY. ACCURATELY DEPICTING THIS
PHENOMENON IN THE GRIDS IS QUITE CHALLENGING...BUT GENERALLY
SPEAKING...LATEST RUC FCSTS APPEAR TO HAVE THE GREATEST GRASP ON
OVERALL SHORT TERM TRENDS...AND THUS WAS RELIED ON HEAVILY FOR
THE HRLY FCST THE REST OF TODAY. DID INCLUDE SOME PATCHY FOG OVER
SOUTH CENTRAL LOUISIANA WHERE KLFT AND KARA HAVE REPORTED 1/2SM OR
LESS AT TIMES THIS MORNING. THIS SHOULD IMPROVE HEADING INTO THE
AFTERNOON...BUT WILL CONTINUE TO MONITOR TRENDS AND MAY HAVE TO
ADD IT FOR THIS AFTERNOON/EVENING FOR AREAS STILL DOWNSTREAM OF
THE FRONT. HAVE NOT LOOKED TOO DEEPLY AT TONIGHT JUST YET...BUT A
QUICK GLANCE REVEALS THE TYPICAL CAVEATS WHICH INCLUDE BORDERLINE
FREEZING TEMPERATURES AND WHETHER ANY PCPN WILL BE ONGOING TO
FREEZE. WILL BE EXAMINING THAT FURTHER FOR THE AFTERNOON PACKAGE.
13
PREV DISCUSSION... /ISSUED 531 AM CST FRI DEC 6 2013/
DISCUSSION...
12Z TAF ISSUANCE.
AVIATION...
COLD FRONT NOW ACROSS LOWER ACADIANA...PAST ARA BUT NOT YET
REACHED PTN. RADAR SHOWS SCT OVERRUNNING SHRA OVER SE TX/C AND SC
LA THIS MORNING...MIXED WITH -DZ NOT DETECTED BY RADAR.
OTHERWISE...LIFR CEILINGS WILL CONTINUE THIS MORNING FOR ALL
SITES...WITH INTERMITTENT IFR VSBY POSSIBLE AS WELL. SHRA EXPECTED
TO INCREASE LATER THIS MORNING INTO THE EARLY AFTERNOON HOURS. CEILINGS
ONLY EXPECTED TO IMPROVE TO IFR AT BEST LATER THIS MORNING INTO
THE AFTERNOON...WITH IMPROVEMENT TO MVFR THIS EVENING.
DML
PREV DISCUSSION... /ISSUED 355 AM CST FRI DEC 6 2013/
DISCUSSION...
SFC ANALYSIS/88D IMAGERY SHOWS THE FRONT RUNNING ROUGHLY FROM KBTR
THROUGH KLFT AND KIYA TO THE COASTAL WATERS SOUTH OF CAMERON.
LOCAL 88DS SHOW SCATTERED LIGHT SHOWERS DEVELOPING MAINLY ALONG
THE FRONT AND PATCHY LIGHT RAIN BEGINNING TO DEVELOP OVER THE NWRN
ZONES. FURTHER NORTH...REGIONAL 88DS SHOW A LARGE AREA OF LIGHT
RAIN...WITH SOME FREEZING RAIN MIXED IN...SPREADING ACROSS NRN TX
INTO THE ARKLATEX.
NO SIGNIFICANT CHANGES WERE MADE TO THE INHERITED GRIDS/ZONES THIS
MORNING. 00Z MODEL RUNS INDICATE THE PRECIP SHIELD TO OUR NW WILL
CONTINUE PUSHING ESEWD THROUGH THE DAY...MOST AFFECTING THE NRN
ZONES WHERE HIGHEST POPS ARE CURRENTLY DISPLAYED. MEANWHILE
ADDITIONAL OVERRUNNING-TYPE RAINS ARE EXPECTED TO DEVELOP ACROSS
THE REMAINDER OF THE FORECAST AREA AS THE FRONT GRADUALLY GETS A
SHOVE FROM FROM THE SHORTWAVE MOVING INTO THE TX BIG BEND REGION
AND FINALLY DEPARTS THE SERN ZONES LATER THIS MORNING. AS COLD AIR
ASSOCIATED WITH BUILDING CANADIAN HIGH PRESSURE WORKS ITS WAY
OVER THE AREA THROUGH TODAY TEMPS ARE EXPECTED TO BASICALLY HOLD
IN THE LOWER 40S ACROSS THE NWRN ZONES.
STILL LOOKING AT THE POSSIBILITY OF WINTRY WEATHER LATE TONIGHT
INTO SATURDAY MORNING ACROSS THE NRN TIER OF ZONES AS FORECAST
SOUNDINGS CONTINUE TO INDICATE A SHALLOW SUBFREEZING LAYER NEAR THE
SFC. STILL NOT SEEING THE NEED TO EXPAND THIS AREA OF FREEZING
PRECIP SWD THOUGH AS FORECAST SOUNDINGS CONTINUE TO SHOW TEMPS
STAYING ABOVE 32F FOR NOW.
A FAIRLY MESSY WEATHER PATTERN LOOKS ON TAP FOR THE WEEKEND AS THE
OVERRUNNING PATTERN LINGERS AND GETS AIDED BY SFC LOW DEVELOPMENT
OVER THE WRN GULF. THE PRECIP SHOULD GRADUALLY DIMINISH INTO
EARLY NEXT WEEK WHEN THE LONGWAVE TROF AXIS PUSHES EWD ACROSS THE
CNTL CONUS AND DRY AIR TAKES OVER THROUGH THE COLUMN. THE CANADIAN
AIRMASS PROGGED TO SLIP SWD ACROSS THE WRN/CNTL CONUS WILL
MAINTAIN COOL TEMPS THROUGH MID-WEEK. RAIN CHANCES RETURN VERY
LATE IN THE FORECAST PERIOD AS A STRONG SHORTWAVE CROSSES THE
REGION AND WORKS IN CONCERT WITH PROGGED COASTAL TROF DEVELOPMENT.
MARINE...
EXTENDED THE DENSE FOG ADVISORY FOR VERMILION BAY/NEAR SHORE
WATERS EAST OF INTRACOASTAL CITY TO 15Z AS VERY LOW VISIBILITIES
WILL REMAIN A THREAT UNTIL THE FRONT PASSES THIS AREA. ALSO ADDED
CAUTION HEADLINES TO SABINE/CALCASIEU LAKES FOR THIS AFTERNOON AS
NRLY WINDS ARE EXPECTED TO INCREASE TO THE 15-20 KNOT RANGE.
OTHERWISE SCA CONDITIONS ARE EXPECTED TO DEVELOP THROUGH THE
AFTERNOON AND EVENING ON THE COASTAL WATERS AS STRONG OFFSHORE
DEVELOPS IN WAKE OF THE FRONT.
08
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 50 36 43 35 49 / 70 30 50 40 50
KBPT 47 36 44 35 46 / 60 30 50 40 50
KAEX 43 32 41 34 43 / 90 30 50 50 60
KLFT 50 36 44 38 54 / 70 30 50 40 60
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 PM CST
SATURDAY FOR THE FOLLOWING ZONES: COASTAL WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA OUT 20 NM...
WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA
FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 PM CST SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM CAMERON LA TO HIGH ISLAND TX OUT
20 NM...WATERS FROM CAMERON LA TO HIGH ISLAND TX FROM 20 TO
60 NM.
SMALL CRAFT ADVISORY UNTIL 6 PM CST SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON LA
OUT 20 NM...WATERS FROM INTRACOASTAL CITY TO CAMERON LA
FROM 20 TO 60 NM.
SMALL CRAFT EXERCISE CAUTION THROUGH SATURDAY AFTERNOON FOR THE
FOLLOWING ZONES: SABINE LAKE.
SMALL CRAFT EXERCISE CAUTION THROUGH SATURDAY AFTERNOON FOR THE
FOLLOWING ZONES: CALCASIEU LAKE.
SMALL CRAFT EXERCISE CAUTION FROM 3 PM CST THIS AFTERNOON
THROUGH SATURDAY AFTERNOON FOR THE FOLLOWING ZONES:
VERMILION BAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1116 AM CST FRI DEC 6 2013
.DISCUSSION...
CDFNT FAIRLY EVIDENT ON VISIBLE SATELLITE AND RADAR IMAGERY
EXTENDING FROM SOUTH CENTRAL LOUISIANA INTO THE WESTERN
GULF...WITH AN EXTENSIVE BLANKET OF POST FRONTAL STRATUS NOW
COVERING ALL BUT EXTREME SE INLAND ZONES AND THE SE THIRD OR SO OF
THE MAOR. DRIZZLE...ALONG WITH PATCHES OF MODERATE RAIN AND A FEW
SHOWERS...PREVAIL IN THE COLD POST FRONTAL AIRMASS. COVERAGE HAS
INCREASED OVER THE PAST COUPLE OF HOURS OR SO...AND THIS SHOULD
CONTINUE HEADING INTO THE EARLY TO MID AFTERNOON...WITH RAIN
CHANCES STARTING TO DECLINE HEADING FROM LATE AFTERNOON THROUGH
THE EVENING. WITH THE EXCEPTION OF LOCATIONS AHEAD OF THE FRONT
WHERE WARMING IS ONGOING...TEMPERATURES ARE EXPECTED TO REMAIN
STEADY IF NOT FALL SLOWLY THROUGH THE DAY. THE CONTRAST IS
STRIKING...WITH LATEST OBS FROM LAFAYETTE AND PATTERSON REPORTING
49 AND 79 DEGREES RESPECTIVELY. ACCURATELY DEPICTING THIS
PHENOMENON IN THE GRIDS IS QUITE CHALLENGING...BUT GENERALLY
SPEAKING...LATEST RUC FCSTS APPEAR TO HAVE THE GREATEST GRASP ON
OVERALL SHORT TERM TRENDS...AND THUS WAS RELIED ON HEAVILY FOR
THE HRLY FCST THE REST OF TODAY. DID INCLUDE SOME PATCHY FOG OVER
SOUTH CENTRAL LOUISIANA WHERE KLFT AND KARA HAVE REPORTED 1/2SM OR
LESS AT TIMES THIS MORNING. THIS SHOULD IMPROVE HEADING INTO THE
AFTERNOON...BUT WILL CONTINUE TO MONITOR TRENDS AND MAY HAVE TO
ADD IT FOR THIS AFTERNOON/EVENING FOR AREAS STILL DOWNSTREAM OF
THE FRONT. HAVE NOT LOOKED TOO DEEPLY AT TONIGHT JUST YET...BUT A
QUICK GLANCE REVEALS THE TYPICAL CAVEATS WHICH INCLUDE BORDERLINE
FREEZING TEMPERATURES AND WHETHER ANY PCPN WILL BE ONGOING TO
FREEZE. WILL BE EXAMINING THAT FURTHER FOR THE AFTERNOON PACKAGE.
13
&&
.PREV DISCUSSION... /ISSUED 531 AM CST FRI DEC 6 2013/
DISCUSSION...
12Z TAF ISSUANCE.
AVIATION...
COLD FRONT NOW ACROSS LOWER ACADIANA...PAST ARA BUT NOT YET
REACHED PTN. RADAR SHOWS SCT OVERRUNNING SHRA OVER SE TX/C AND SC
LA THIS MORNING...MIXED WITH -DZ NOT DETECTED BY RADAR.
OTHERWISE...LIFR CEILINGS WILL CONTINUE THIS MORNING FOR ALL
SITES...WITH INTERMITTENT IFR VSBY POSSIBLE AS WELL. SHRA EXPECTED
TO INCREASE LATER THIS MORNING INTO THE EARLY AFTERNOON HOURS. CEILINGS
ONLY EXPECTED TO IMPROVE TO IFR AT BEST LATER THIS MORNING INTO
THE AFTERNOON...WITH IMPROVEMENT TO MVFR THIS EVENING.
DML
PREV DISCUSSION... /ISSUED 355 AM CST FRI DEC 6 2013/
DISCUSSION...
SFC ANALYSIS/88D IMAGERY SHOWS THE FRONT RUNNING ROUGHLY FROM KBTR
THROUGH KLFT AND KIYA TO THE COASTAL WATERS SOUTH OF CAMERON.
LOCAL 88DS SHOW SCATTERED LIGHT SHOWERS DEVELOPING MAINLY ALONG
THE FRONT AND PATCHY LIGHT RAIN BEGINNING TO DEVELOP OVER THE NWRN
ZONES. FURTHER NORTH...REGIONAL 88DS SHOW A LARGE AREA OF LIGHT
RAIN...WITH SOME FREEZING RAIN MIXED IN...SPREADING ACROSS NRN TX
INTO THE ARKLATEX.
NO SIGNIFICANT CHANGES WERE MADE TO THE INHERITED GRIDS/ZONES THIS
MORNING. 00Z MODEL RUNS INDICATE THE PRECIP SHIELD TO OUR NW WILL
CONTINUE PUSHING ESEWD THROUGH THE DAY...MOST AFFECTING THE NRN
ZONES WHERE HIGHEST POPS ARE CURRENTLY DISPLAYED. MEANWHILE
ADDITIONAL OVERRUNNING-TYPE RAINS ARE EXPECTED TO DEVELOP ACROSS
THE REMAINDER OF THE FORECAST AREA AS THE FRONT GRADUALLY GETS A
SHOVE FROM FROM THE SHORTWAVE MOVING INTO THE TX BIG BEND REGION
AND FINALLY DEPARTS THE SERN ZONES LATER THIS MORNING. AS COLD AIR
ASSOCIATED WITH BUILDING CANADIAN HIGH PRESSURE WORKS ITS WAY
OVER THE AREA THROUGH TODAY TEMPS ARE EXPECTED TO BASICALLY HOLD
IN THE LOWER 40S ACROSS THE NWRN ZONES.
STILL LOOKING AT THE POSSIBILITY OF WINTRY WEATHER LATE TONIGHT
INTO SATURDAY MORNING ACROSS THE NRN TIER OF ZONES AS FORECAST
SOUNDINGS CONTINUE TO INDICATE A SHALLOW SUBFREEZING LAYER NEAR THE
SFC. STILL NOT SEEING THE NEED TO EXPAND THIS AREA OF FREEZING
PRECIP SWD THOUGH AS FORECAST SOUNDINGS CONTINUE TO SHOW TEMPS
STAYING ABOVE 32F FOR NOW.
A FAIRLY MESSY WEATHER PATTERN LOOKS ON TAP FOR THE WEEKEND AS THE
OVERRUNNING PATTERN LINGERS AND GETS AIDED BY SFC LOW DEVELOPMENT
OVER THE WRN GULF. THE PRECIP SHOULD GRADUALLY DIMINISH INTO
EARLY NEXT WEEK WHEN THE LONGWAVE TROF AXIS PUSHES EWD ACROSS THE
CNTL CONUS AND DRY AIR TAKES OVER THROUGH THE COLUMN. THE CANADIAN
AIRMASS PROGGED TO SLIP SWD ACROSS THE WRN/CNTL CONUS WILL
MAINTAIN COOL TEMPS THROUGH MID-WEEK. RAIN CHANCES RETURN VERY
LATE IN THE FORECAST PERIOD AS A STRONG SHORTWAVE CROSSES THE
REGION AND WORKS IN CONCERT WITH PROGGED COASTAL TROF DEVELOPMENT.
MARINE...
EXTENDED THE DENSE FOG ADVISORY FOR VERMILION BAY/NEAR SHORE
WATERS EAST OF INTRACOASTAL CITY TO 15Z AS VERY LOW VISIBILITIES
WILL REMAIN A THREAT UNTIL THE FRONT PASSES THIS AREA. ALSO ADDED
CAUTION HEADLINES TO SABINE/CALCASIEU LAKES FOR THIS AFTERNOON AS
NRLY WINDS ARE EXPECTED TO INCREASE TO THE 15-20 KNOT RANGE.
OTHERWISE SCA CONDITIONS ARE EXPECTED TO DEVELOP THROUGH THE
AFTERNOON AND EVENING ON THE COASTAL WATERS AS STRONG OFFSHORE
DEVELOPS IN WAKE OF THE FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 50 36 43 35 / 70 30 50 40
KBPT 47 36 44 35 / 60 30 50 40
KAEX 43 32 41 34 / 90 30 50 50
KLFT 50 36 44 38 / 70 30 50 40
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 PM CST
SATURDAY FOR COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY LA OUT 20 NM-WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 PM CST SATURDAY FOR COASTAL WATERS
FROM CAMERON LA TO HIGH ISLAND TX OUT 20 NM-WATERS FROM
CAMERON LA TO HIGH ISLAND TX FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 PM CST SATURDAY FOR COASTAL WATERS
FROM INTRACOASTAL CITY TO CAMERON LA OUT 20 NM-WATERS FROM
INTRACOASTAL CITY TO CAMERON LA FROM 20 TO 60 NM.
SMALL CRAFT EXERCISE CAUTION THROUGH SATURDAY AFTERNOON FOR
SABINE LAKE.
SMALL CRAFT EXERCISE CAUTION THROUGH SATURDAY AFTERNOON FOR
CALCASIEU LAKE.
SMALL CRAFT EXERCISE CAUTION FROM 3 PM CST THIS AFTERNOON
THROUGH SATURDAY AFTERNOON FOR VERMILION BAY.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
239 PM EST FRI DEC 6 2013
LATEST UPDATE...
SYNOPSIS/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 238 PM EST FRI DEC 6 2013
THE COLDEST EARLY DECEMBER TEMPERATURES SINCE 2005 ARE EXPECTED.
SNOW SHOWERS WILL PREVAIL WITH 1 TO 2 INCHES OF ACCUMULATION NEAR
AND WEST OF US-131 THROUGH SATURDAY EVENING. FROM SUNDAY NIGHT
INTO MONDAY EXPECT A GENERAL SNOWFALL OF 1 TO 3 INCHES. LAKE
EFFECT SNOW SHOWERS ARE EXPECTED MIDDAY MONDAY THROUGH THURSDAY
WITH SIGNIFICANT ACCUMULATIONS POSSIBLE WEST OF US-131.
&&
.UPDATE...
ISSUED AT 1128 AM EST FRI DEC 6 2013
I UPDATED THE FORECAST TO SHOW HIGHER PROBABILITIES OF LIGHT SNOW
SHOWERS WEST OF US-131 BASED ON RADAR RETURNS...SURFACE OBS (BIV
1 1/2-4SM -SN/ MKG 2-4SM -SN)...LAKE ENHANCED IR IMAGE LOOPS AND
USING THE OMEGA AND RH FROM THE LATEST RAP MODEL IN THE 0-2KM
LAYER. THE LATEST RAP MODEL SUGGESTS THE AREA OF BEST LIFT WILL
SHIFT SOUTH THIS AFTERNOON FROM WHITEHALL TO SOUTH HAVEN NOW... TO
HOLLAND TO BENTON HARBOR BY MID AFTERNOON. INLAND EXPECT JUST
FLURRIES (I PUT FLURRIES IN THE GRIDS TOO). AS ALWAYS IN THESE
SITUATIONS EVEN THE HIGH RES MODELS ARE HAVING A PROBLEM
FORECASTING THIS TYPE OF SNOW SHOWER ACTIVITY.
I STILL EXPECT THE BETTER ACCUMULATIONS TONIGHT INTO SATURDAY SO I
UPDATED THOSE GRIDS TO SHOW HIGHER PROBABILITIES. STILL
ACCUMULATIONS SHOULD BE LESS THAN 2 INCHES IN MOST PLACES.
ELSEWHERE AND OTHERWISE THE FORECAST IS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 332 AM EST FRI DEC 6 2013
THE MAIN FOCUS OF THE SHORT TERM PORTION OF THE FCST REMAINS LAKE
EFFECT TRENDS THROUGH THE PERIOD WITH COLD AIR EXPECTED TO REMAIN IN
PLACE. NO REAL CHANGES HAVE BEEN MADE WITH THE FCST AS MODELS ARE
SHOWING GOOD RUN TO RUN CONSISTENCY.
LAKE EFFECT HAS BEEN SLOW TO GET STARTED WITH THIS COLD AIR
MASS...AND THAT CONTINUES TO BE THE CASE THIS MORNING. SOME FLURRIES
ARE BEING REPORTED AT KCAD JUST NORTH OF THE CWFA...BUT NOTHING IN
THE CWFA AS OF 08Z THIS MORNING. THE LACK OF MOISTURE DEPTH AND LACK
OF LOW LEVEL CONVERGENCE UNDER FAIRLY ROBUST SUBSIDENCE WITH THE
ENTRANCE REGION OF THE STRONG UPPER JET IS OVERCOMING THE HEALTHY
OVER LAKE INSTABILITY.
WE DO EXPECT TO SEE A FEW SNOW SHOWERS DEVELOP TODAY. ONGOING CAA
WILL HELP A BIT TO LOWER THE DGZ INTO THE LIMITED MOISTURE LAYER A
BIT BETTER. THE AFOREMENTIONED LIMITING FACTORS WILL KEEP ANY SNOW
SHOWERS UNDER CONTROL TODAY. THE ONGOING CAA WILL LIMIT THE AMOUNT
OF WARMING FOR TEMPS TODAY. HIGHS SHOULD NOT CLIMB ABOVE THE UPPER
20S AFTER WE LOSE A FEW DEGREES THIS MORNING.
WE CONTINUE TO ANTICIPATE AN UPTICK IN LAKE EFFECT SNOW SHOWER
ACTIVITY FOR TONIGHT AND EARLY SAT MORNING. THIS UPTICK IS EXPECTED
TO BE THE RESULT OF A SHORT WAVE/PV ANOMALY CURRENTLY OVER NM THIS
MORNING LIFTING TO THE NE OVER THE AREA TONIGHT. INVERSION HEIGHTS
WILL BUMP UP TO AROUND 5K FEET OR SO. AT THE SAME TIME...A BIT OF
MID LEVEL MOISTURE WILL TRY TO HELP SNOW SHOWER GENERATION WITH A
SEEDER FEEDER TYPE OF SCENARIO. THERE WILL BE ABOUT 4-6K FT OF DRY
AIR IN BETWEEN THE LAYERS...SO IT IS NOT A GUARANTEE THIS WILL
ABSOLUTELY HELP. THE DGZ WILL BE SATURATED QUITE A BIT WHICH WILL
HELP FOR THE SNOW CAUSE. WNW FLOW FAVORED AREAS WILL SEE THE BEST
CHC OF SNOW SHOWERS AND SOME ACCUMULATIONS. LOW LEVEL CONVERGENCE IS
STILL LACKING...SO WE DO NOT EXPECT SNOW AMOUNTS TO GET OUT OF HAND.
WE WILL SEE THE LAKE EFFECT SNOW SHOWERS THEN GRADUALLY DIMINISH IN
COVERAGE AND INTENSITY DURING THE DAY ON SAT. THE NM SHORT WAVE WILL
EXIT THE AREA AND SUBSIDENCE WILL TAKE CONTROL ONCE AGAIN. INVERSION
HEIGHTS ARE EXPECTED TO LOWER TO AROUND 3K FEET...BEFORE LOW LEVEL
MOISTURE IS EXPECTED TO DISSIPATE WITH A STRONG ARCTIC SFC RIDGE
MOVING DIRECTLY OVERHEAD. THIS WILL ALLOW FOR A COLD SAT NIGHT WITH
SOME CLEARING LIKELY.
THE CLEARING AND BREAK IN THE SNOW SHOWERS WILL BE SHORT LIVED. WE
WILL SEE ADDITIONAL SHORT WAVE ENERGY EJECT OUT FROM THE WRN U.S.
TROUGH AND APPROACH THE AREA SUN AFTERNOON. SOME MOISTURE FROM THE
STRONG STORM SYSTEM EXPECTED ACROSS THE SE STATES WILL WRAP INTO
THIS WAVE AS IT IS PASSING ACROSS THE STATE. THE MOISTURE IS NOT
THAT RICH AS THE BEST MOISTURE WILL REMAIN WELL SE OF THE AREA WITH
THE MAIN BAROCLINIC/FRONTAL ZONE ACROSS THE SE PORTION OF THE
COUNTRY. FORCING IS LIMITED TOO THIS FAR NORTH WITH THE MAIN
ISENTROPIC ASCENT REMAINING WELL SOUTH AND EAST. THIS LOOKS LIKE A
LIGHT SNOW EVENT WHERE MOST OF THE AREA WILL SEE AN INCH OR TWO OF
SNOW ACCUMULATION.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 332 AM EST FRI DEC 6 2013
THE SYNOPTIC SYSTEM FOR SUNDAY NIGHT CONTINUES TO LOOK LESS
IMPRESSIVE WITH EACH MODEL RUN. WEAK/BAGGY SFC LOW PRESSURE PATTERN
PASSES ACROSS LOWER MI WITH ONLY AROUND ONE TENTH OF AN INCH OF QPF.
NO DECENT/AMPLIFIED SHORTWAVE IS PRESENT ALOFT...AND INSTEAD IT IS
JUST A SHEARED OUT/ELONGATED VORTICITY PATTERN.
THERE IS ALSO THE ISSUE OF A POTENTIAL MID LEVEL DRY SLOT SWEEPING
IN WHICH COULD LEAD TO MORE OF A LIGHT FREEZING RAIN/DRIZZLE THREAT
SUNDAY NIGHT RATHER THAN LIGHT SNOW. WILL KEEP LIKELY POPS FOR LIGHT
SNOW OVER THE ENTIRE AREA FOR NOW BUT IF THE TRENDS CONTINUE THEN
THE FREEZING PRECIP THREAT MAY NEED TO BE ADDED IN LATER FORECASTS.
COLD ADVECTION FOLLOWS ON MONDAY BEHIND THE WEAK EXITING SYSTEM BUT
THE REALLY COLD ARCTIC AIR DOES NOT ARRIVE UNTIL TUESDAY OR TUESDAY
NIGHT. IT IS THE CLIPPER SYSTEM TRACKING ACROSS LAKE SUPERIOR WHICH
BRINGS IN THE COLD AIR AND PERHAPS A BETTER RISK OF SOME
ACCUMULATING LAKE EFFECT SNOW. EVEN THIS IS QUESTIONABLE HOWEVER
SINCE THE CORE OF THE UPPER JET DOES NOT DIP SOUTH OF THE STATE AND
MOISTURE IS RATHER SHALLOW/LIMITED.
THE LAKE EFFECT SNOW SHOWER THREAT IS EXPECTED TO DIMINISH THURSDAY
AS SURFACE RIDGING BUILDS IN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1233 PM EST FRI DEC 6 2013
A MIX OF VFR AND MVFR CEILINGS CAN BE EXPECTED OVER THE NEXT 24
HOURS. THE BULK OF THE MVFR WILL BE DOWN WIND FROM LAKE MICHIGAN...
WITH NW OR WNW FLOW. THE MVFR CONDITIONS SHOULD BE MOST PERSISTENT
AT AZO...WITH VFR AND OCCASIONAL MVFR EXPECTED FOR THE REMAINDER
OF THE TAF SITES.
THERE WILL ALSO BE LIGHT SNOW SHOWERS COMING OFF THE LAKE. MOST
VSBYS WILL BE REDUCED INTO THE MVFR RANGE...HOWEVER A FEW ISOLATED
SNOW SHOWERS MAY BRING VSBYS DOWN INTO THE IFR RANGE. ONCE
AGAIN...WITH THE NW FLOW...AZO SHOULD SEE MORE FREQUENT SNOW
SHOWERS THEN THE REST OF THE TAF SITES. THE HIGHEST IMPACT SNOW
SHOWERS SHOULD OCCUR FROM ROUGHLY 04Z TO 14Z SATURDAY WHEN THE
BEST LOW LEVEL MOISTURE IS REALIZED.
&&
.MARINE...
ISSUED AT 238 PM EST FRI DEC 6 2013
LITTLE REASON TO CHANGE OUR FORECAST OR HEADLINES AT THIS POINT.
NORTHWEST WINDS OF 15 TO 25 KNOTS WILL KEEP WAVES IN THE 4 TO 7
FOOT RANGE INTO SATURDAY BEFORE WINDS DIMINISH LATE IN THE DAY
ALLOWING WAVE HEIGHTS TO ALSO DIMINISH.
&&
.HYDROLOGY...
ISSUED AT 238 PM EST FRI DEC 6 2013
WE WILL CONTINUE TO MONITOR THE ICE JAM THREAT AS THE COLD WEATHER
PERSISTS. THE GENERAL SNOWFALL SUNDAY NIGHT INTO MONDAY MAY
FACILITATE ICE FORMATION ON AREA RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 1 AM EST SUNDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...WDM
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...JK
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1233 PM EST FRI DEC 6 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 332 AM EST FRI DEC 6 2013
COLD AIR IS EXPECTED TO REMAIN IN PLACE THROUGH THE WEEKEND. THERE
WILL BE SOME LAKE EFFECT SNOW SHOWERS THROUGH SATURDAY. NO
SIGNIFICANT ACCUMULATIONS ARE EXPECTED. MOST OF THE AREA SHOULD SEE
LIGHT SNOW ACCUMULATIONS LATE SUNDAY THROUGH MONDAY AS A WAVE OF LOW
PRESSURE MOVES THROUGH THE AREA.
COLDER AIR WILL MOVE IN DURING THE EARLY PORTION OF NEXT WEEK.
CONDITIONS LOOK A BIT MORE FAVORABLE FOR LAKE EFFECT SNOW
ACCUMULATIONS NEXT WEEK...ESPECIALLY ACROSS THE WESTERN HALF OF THE
AREA.
&&
.UPDATE...
ISSUED AT 1128 AM EST FRI DEC 6 2013
I UPDATED THE FORECAST TO SHOW HIGHER PROBABILITIES OF LIGHT SNOW
SHOWERS WEST OF US-131 BASED ON RADAR RETURNS...SURFACE OBS (BIV
1 1/2-4SM -SN/ MKG 2-4SM -SN)...LAKE ENHANCED IR IMAGE LOOPS AND
USING THE OMEGA AND RH FROM THE LATEST RAP MODEL IN THE 0-2KM
LAYER. THE LATEST RAP MODEL SUGGESTS THE AREA OF BEST LIFT WILL
SHIFT SOUTH THIS AFTERNOON FROM WHITEHALL TO SOUTH HAVEN NOW... TO
HOLLAND TO BENTON HARBOR BY MID AFTERNOON. INLAND EXPECT JUST
FLURRIES (I PUT FLURRIES IN THE GRIDS TOO). AS ALWAYS IN THESE
SITUATIONS EVEN THE HIGH RES MODELS ARE HAVING A PROBLEM
FORECASTING THIS TYPE OF SNOW SHOWER ACTIVITY.
I STILL EXPECT THE BETTER ACCUMULATIONS TONIGHT INTO SATURDAY SO I
UPDATED THOSE GRIDS TO SHOW HIGHER PROBABILITIES. STILL
ACCUMULATIONS SHOULD BE LESS THAN 2 INCHES IN MOST PLACES.
ELSEWHERE AND OTHERWISE THE FORECAST IS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 332 AM EST FRI DEC 6 2013
THE MAIN FOCUS OF THE SHORT TERM PORTION OF THE FCST REMAINS LAKE
EFFECT TRENDS THROUGH THE PERIOD WITH COLD AIR EXPECTED TO REMAIN IN
PLACE. NO REAL CHANGES HAVE BEEN MADE WITH THE FCST AS MODELS ARE
SHOWING GOOD RUN TO RUN CONSISTENCY.
LAKE EFFECT HAS BEEN SLOW TO GET STARTED WITH THIS COLD AIR
MASS...AND THAT CONTINUES TO BE THE CASE THIS MORNING. SOME FLURRIES
ARE BEING REPORTED AT KCAD JUST NORTH OF THE CWFA...BUT NOTHING IN
THE CWFA AS OF 08Z THIS MORNING. THE LACK OF MOISTURE DEPTH AND LACK
OF LOW LEVEL CONVERGENCE UNDER FAIRLY ROBUST SUBSIDENCE WITH THE
ENTRANCE REGION OF THE STRONG UPPER JET IS OVERCOMING THE HEALTHY
OVER LAKE INSTABILITY.
WE DO EXPECT TO SEE A FEW SNOW SHOWERS DEVELOP TODAY. ONGOING CAA
WILL HELP A BIT TO LOWER THE DGZ INTO THE LIMITED MOISTURE LAYER A
BIT BETTER. THE AFOREMENTIONED LIMITING FACTORS WILL KEEP ANY SNOW
SHOWERS UNDER CONTROL TODAY. THE ONGOING CAA WILL LIMIT THE AMOUNT
OF WARMING FOR TEMPS TODAY. HIGHS SHOULD NOT CLIMB ABOVE THE UPPER
20S AFTER WE LOSE A FEW DEGREES THIS MORNING.
WE CONTINUE TO ANTICIPATE AN UPTICK IN LAKE EFFECT SNOW SHOWER
ACTIVITY FOR TONIGHT AND EARLY SAT MORNING. THIS UPTICK IS EXPECTED
TO BE THE RESULT OF A SHORT WAVE/PV ANOMALY CURRENTLY OVER NM THIS
MORNING LIFTING TO THE NE OVER THE AREA TONIGHT. INVERSION HEIGHTS
WILL BUMP UP TO AROUND 5K FEET OR SO. AT THE SAME TIME...A BIT OF
MID LEVEL MOISTURE WILL TRY TO HELP SNOW SHOWER GENERATION WITH A
SEEDER FEEDER TYPE OF SCENARIO. THERE WILL BE ABOUT 4-6K FT OF DRY
AIR IN BETWEEN THE LAYERS...SO IT IS NOT A GUARANTEE THIS WILL
ABSOLUTELY HELP. THE DGZ WILL BE SATURATED QUITE A BIT WHICH WILL
HELP FOR THE SNOW CAUSE. WNW FLOW FAVORED AREAS WILL SEE THE BEST
CHC OF SNOW SHOWERS AND SOME ACCUMULATIONS. LOW LEVEL CONVERGENCE IS
STILL LACKING...SO WE DO NOT EXPECT SNOW AMOUNTS TO GET OUT OF HAND.
WE WILL SEE THE LAKE EFFECT SNOW SHOWERS THEN GRADUALLY DIMINISH IN
COVERAGE AND INTENSITY DURING THE DAY ON SAT. THE NM SHORT WAVE WILL
EXIT THE AREA AND SUBSIDENCE WILL TAKE CONTROL ONCE AGAIN. INVERSION
HEIGHTS ARE EXPECTED TO LOWER TO AROUND 3K FEET...BEFORE LOW LEVEL
MOISTURE IS EXPECTED TO DISSIPATE WITH A STRONG ARCTIC SFC RIDGE
MOVING DIRECTLY OVERHEAD. THIS WILL ALLOW FOR A COLD SAT NIGHT WITH
SOME CLEARING LIKELY.
THE CLEARING AND BREAK IN THE SNOW SHOWERS WILL BE SHORT LIVED. WE
WILL SEE ADDITIONAL SHORT WAVE ENERGY EJECT OUT FROM THE WRN U.S.
TROUGH AND APPROACH THE AREA SUN AFTERNOON. SOME MOISTURE FROM THE
STRONG STORM SYSTEM EXPECTED ACROSS THE SE STATES WILL WRAP INTO
THIS WAVE AS IT IS PASSING ACROSS THE STATE. THE MOISTURE IS NOT
THAT RICH AS THE BEST MOISTURE WILL REMAIN WELL SE OF THE AREA WITH
THE MAIN BAROCLINIC/FRONTAL ZONE ACROSS THE SE PORTION OF THE
COUNTRY. FORCING IS LIMITED TOO THIS FAR NORTH WITH THE MAIN
ISENTROPIC ASCENT REMAINING WELL SOUTH AND EAST. THIS LOOKS LIKE A
LIGHT SNOW EVENT WHERE MOST OF THE AREA WILL SEE AN INCH OR TWO OF
SNOW ACCUMULATION.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 332 AM EST FRI DEC 6 2013
THE SYNOPTIC SYSTEM FOR SUNDAY NIGHT CONTINUES TO LOOK LESS
IMPRESSIVE WITH EACH MODEL RUN. WEAK/BAGGY SFC LOW PRESSURE PATTERN
PASSES ACROSS LOWER MI WITH ONLY AROUND ONE TENTH OF AN INCH OF QPF.
NO DECENT/AMPLIFIED SHORTWAVE IS PRESENT ALOFT...AND INSTEAD IT IS
JUST A SHEARED OUT/ELONGATED VORTICITY PATTERN.
THERE IS ALSO THE ISSUE OF A POTENTIAL MID LEVEL DRY SLOT SWEEPING
IN WHICH COULD LEAD TO MORE OF A LIGHT FREEZING RAIN/DRIZZLE THREAT
SUNDAY NIGHT RATHER THAN LIGHT SNOW. WILL KEEP LIKELY POPS FOR LIGHT
SNOW OVER THE ENTIRE AREA FOR NOW BUT IF THE TRENDS CONTINUE THEN
THE FREEZING PRECIP THREAT MAY NEED TO BE ADDED IN LATER FORECASTS.
COLD ADVECTION FOLLOWS ON MONDAY BEHIND THE WEAK EXITING SYSTEM BUT
THE REALLY COLD ARCTIC AIR DOES NOT ARRIVE UNTIL TUESDAY OR TUESDAY
NIGHT. IT IS THE CLIPPER SYSTEM TRACKING ACROSS LAKE SUPERIOR WHICH
BRINGS IN THE COLD AIR AND PERHAPS A BETTER RISK OF SOME
ACCUMULATING LAKE EFFECT SNOW. EVEN THIS IS QUESTIONABLE HOWEVER
SINCE THE CORE OF THE UPPER JET DOES NOT DIP SOUTH OF THE STATE AND
MOISTURE IS RATHER SHALLOW/LIMITED.
THE LAKE EFFECT SNOW SHOWER THREAT IS EXPECTED TO DIMINISH THURSDAY
AS SURFACE RIDGING BUILDS IN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1233 PM EST FRI DEC 6 2013
A MIX OF VFR AND MVFR CEILINGS CAN BE EXPECTED OVER THE NEXT 24
HOURS. THE BULK OF THE MVFR WILL BE DOWN WIND FROM LAKE MICHIGAN...
WITH NW OR WNW FLOW. THE MVFR CONDITIONS SHOULD BE MOST PERSISTENT
AT AZO...WITH VFR AND OCCASIONAL MVFR EXPECTED FOR THE REMAINDER
OF THE TAF SITES.
THERE WILL ALSO BE LIGHT SNOW SHOWERS COMING OFF THE LAKE. MOST
VSBYS WILL BE REDUCED INTO THE MVFR RANGE...HOWEVER A FEW ISOLATED
SNOW SHOWERS MAY BRING VSBYS DOWN INTO THE IFR RANGE. ONCE
AGAIN...WITH THE NW FLOW...AZO SHOULD SEE MORE FREQUENT SNOW
SHOWERS THEN THE REST OF THE TAF SITES. THE HIGHEST IMPACT SNOW
SHOWERS SHOULD OCCUR FROM ROUGHLY 04Z TO 14Z SATURDAY WHEN THE
BEST LOW LEVEL MOISTURE IS REALIZED.
&&
.MARINE...
ISSUED AT 332 AM EST FRI DEC 6 2013
WE ARE EXTENDING THE SMALL CRAFT ADVISORY FOR THE ENTIRE NEARSHORE
THROUGH 06Z SUN WITH THIS FCST PACKAGE. WINDS WILL COME DOWN TO
AROUND 15 TO 20 KNOTS TODAY AND REMAIN THERE THROUGH SAT. THE
ONSHORE FLOW AND UNSTABLE CONDITIONS WITH THE COLD AIR COMING IN
OVER THE LAKE WILL KEEP WAVES ABOVE 4 FEET THROUGH SAT. THERE SHOULD
BE A BREAK SAT NIGHT AND EARLY SUN.
&&
.HYDROLOGY...
ISSUED AT 332 AM EST FRI DEC 6 2013
THE ONLY CONCERN WITH HYDROLOGY REMAINS THE THREAT FOR ICE
DEVELOPMENT OVER THE NEXT WEEK. ARCTIC COLD AIR EXPECTED OVER THE
AREA THROUGH MOST OF THE NEXT WEEK WILL HELP ICE DEVELOPMENT. AS THE
ICE DEVELOPS...WE WILL BE MONITORING THE POTENTIAL FOR ICE JAMS TO
FORM.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 1 AM EST SUNDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...JK
HYDROLOGY...NJJ
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1156 AM EST FRI DEC 6 2013
.AVIATION...
//DISCUSSION...
AN MVFR STRATUS DECK HAS BEEN ON THE DOORSTEP OF MBS FOR THE LAST
HOUR. THE COMBINATION OF THE LOW LEVEL MOISTURE FLUX OFF LAKE
MICHIGAN AND THE DEPTH OF THE LOW LEVEL INVERSION SHOULD SUSTAIN
SOME DEGREE OF LOW CLOUDS INTO AT LEAST MBS THIS AFTERNOON AND
EVENING. THE MAIN LIMITING FACTOR WILL BE THE VERY DRY ARCTIC AIR
NOW ENVELOPING THE REGION. THE INCREASING RESPONSE NOTED OFF LAKE
MICHIGAN MAY ALLOW SOME OF THE STRATO CU TO PERIODICALLY ADVANCE
ACROSS FNT AND PTK THIS EVENING.
FOR DTW...THERE IS GROWING CONFIDENCE THAT POOR MOISTURE QUALITY
WILL KEEP ANY LIGHT SNOW/FLURRIES WELL SOUTH OF METRO THIS EVENING.
ALTHOUGH STRATO CU FROM THE WEST SIDE OF THE STATE WILL ATTEMPT TO
PUSH TOWARD THE EAST...THE DEGREE OF LOW LEVEL DRY AIR AND SLIGHT
DOWNSLOPE COMPONENT INTO METRO UNDER A WNW FLOW SUPPORTS NOTHING
MORE THAN SCT MVFR CLOUD BASES THIS EVENING.
//DTW THRESHOLD THREATS...
* LOW CONFIDENCE ON CEILINGS BELOW 5000 FT THIS EVENING AND
OVERNIGHT.
&&
.PREV DISCUSSION...ISSUED 1008 AM EST FRI DEC 6 2013
UPDATE...
THE THICK CANOPY OF MID/HIGH CLOUDS AND WEAK LOW LEVEL COLD AIR
ADVECTION THROUGH THE AFTERNOON WILL INHIBIT MUCH IF ANY DIURNAL
RESPONSE. THIS WILL SUPPORT A MINOR DOWNWARD ADJUSTMENT TO TEMPS
THIS AFTERNOON. THE DEPTH OF THE COLD AIR HAS BEEN INCREASING OVER
THE WESTERN GREAT LAKES WHICH IS LEADING TO A BETTER RESPONSE OFF
LAKE MI. THE 12Z DTX SOUNDING SHOWED A DEEP INVERSION BASED NEAR
920MB. THIS SHOULD ALLOW A GOOD DUCT FOR THE WESTWARD EXPANSION OF
LAKE STRATO CU. RAP SOUNDINGS ON BUFKIT SUGGEST SUPERSATURATION
WITH RESPECT TO ICE NEAR THE INVERSION LEVEL. SO IT SHOULD NOT BE
DIFFICULT TO GENERATE SOME FLURRIES FROM THESE LOWER BASED CLOUDS.
THIS WILL BE MORE PROBABLE ACROSS THE SAGINAW VALLEY AND THUMB
GIVEN THE WESTERLY FLOW. FARTHER SOUTH...THE LOW LEVEL FLOW
BECOMES HIGHLY DIVERGENT WHICH MAY KEEP THE LOW CLOUDS CONFINED TO
WRN LOWER MI THROUGH THE AFTERNOON.
PREV DISCUSSION...ISSUED 356 AM EST FRI DEC 6 2013
SHORT TERM...TODAY AND TONIGHT
THE WEATHER FOR SOUTHEASTERN MICHIGAN WILL BE INFLUENCED BY A
BAROCLINIC ZONE THAT IS IN PLACE FROM THE EASTERN GREAT LAKES
THROUGH MUCH OF THE OHIO RIVER VALLEY. THE FRONTAL BOUNDARY WILL
BECOME QUASI-STATIONARY TODAY AS THE VERY STRONG...POLAR JET AXIS
OVERHEAD BECOMES FAIRLY STATIC. CHARACTERISTICS OF THE FRONT OFFERED
BY CROSS SECTIONS ARE: 1. GRADUALLY SLOPED 2. A DOUBLE GRADIENT
STRUCTURE AT ROUGHLY 750 MB AND 550 MB.
A WAVE IS EXPECTED TO RIPPLE ALONG THE BAROCLINIC ZONE LATE THIS
AFTERNOON AS A LOWER TROPOSPHERIC REFLECTION OF RIGHT ENTRANCE
REGION DYNAMICS. OVERALL PRECIPITATION CHANCES WILL BE NEAR ZERO FOR
MUCH OF THE CWA WITH CHANCES VERY LOW ACROSS MONROE COUNTY. THE
REASON IS ANALYSES OF LOW TO MID TROPOSPHERIC -DIV AND DEFORMATION
ADVERTISE VERY LITTLE FORCING. IN ADDITION...CROSS SECTIONS SUPPORT
SUBSIDENCE THIS AFTERNOON BETWEEN THE 750 MB AND 550 MB GRADIENTS
ALONG WITH RELATIVELY HIGH STATIC STABILITY THROUGH A GOOD CHUNK OF
THE COLUMN. A DRY LAYER BELOW THE 750MB GRADIENT WILL PROVIDE AN
EVAPORATION BUFFER. IN THE SPIRIT OF CONTINUITY...CONTINUED TO
INCLUDE A LOW CHANCE POP OF LIGHT SNOW FOR MONROE COUNTY BETWEEN
21-02Z BUT ANY SNOWFALL...IF ANY...WILL BE NEGLIGIBLE. SOME FORCING
VERY HIGH IN COLUMN IS STILL EXPECTED TO OVERLAP SOUTHEASTERN
MICHIGAN WHICH SHOULD PROVIDE AN ABUNDANCE OF HIGH CLOUD FOR MUCH OF
THE DAYLIGHT HOURS.
SLUGGISH MOVEMENT OF THE FRONT TODAY WILL GIVE SOME POTENTIAL AT
AFTERNOON HIGHS DESPITE THE CLOUDS. FREEZING MARK SOUTH...TO MIDDLE
20S NORTH. WIND CHILLS WILL DROP INTO THE TEENS THIS MORNING...THEN
STRUGGLE TO CLIMB ABOVE 20 FOR THE AFTERNOON. SUBSIDENCE OCCURRING
BEHIND THE WAVE LATE TONIGHT ALONG WITH DRY AIR SHOULD ALLOW CLOUDS
TO SCATTER AN HOUR OR TWO BEFORE SUNRISE. TEMPERATURES WILL HAVE THE
POTENTIAL TO DROP...LOWS IN THE TEENS WIND CHILLS IN THE SINGLE
DIGITS FOR ALL OF SOUTHEASTERN MICHIGAN.
LONG TERM...SATURDAY THROUGH THURSDAY
HIGH AMPLITUDE MID LEVEL FLOW ANCHORED BY A SPRAWLING LONGWAVE
TROUGH WILL REMAIN THE CONTROLLING LARGE SCALE FEATURE WELL INTO
NEXT WEEK. THE WEEKEND BEGINS WITH SE MICHIGAN INITIALLY RESIDING
ALONG THE EASTERN EXTENSION OF THE MAIN HEIGHT FALL CENTER AND WELL
WITHIN THE COLD DOME PERPETUATED BY AN INBOUND 1040 MB ARCTIC HIGH.
AMBIENT AIRMASS WILL CARRY A DEEP DRY LAYER ABOVE 900 MB...WHILE A
CHECK OF UPSTREAM SOUNDINGS ACROSS LAKE MICHIGAN SHOW A PROFILE ALSO
LACKING IN MOISTURE DEPTH WITH SUPPRESSED INVERSION HEIGHTS. THIS
WOULD INDICATE THE OPPORTUNITY FOR A LAKE AND/OR DIURNALLY ENHANCED
STRATOCU FIELD WILL BE LIMITED. SOME LINGERING EARLY STRATUS MAY
EXIST...PARTICULARLY ACROSS THE NORTH WITH THE RESIDUAL MOISTURE
SOURCE FROM TODAY PERHAPS SLOWER TO MIX OUT. MAIN STORY WILL BE
TEMPERATURES...WITH EVEN A HIGH DEGREE OF INSOLATION STRUGGLING TO
MODERATE A THERMAL PROFILE CARRYING 925 MB TEMPERATURES IN THE -11
TO -12C RANGE. THIS WILL TRANSLATE INTO HIGHS OF LOWER TO MIDDLE
20S...OR A GOOD 15 DEGREE BELOW EARLY DECEMBER NORMS. THE EXISTING
SURFACE RIDGING AND DEEP DRY LAYER WILL PROMOTE A GOOD RADIATIONAL
COOLING RESPONSE SATURDAY NIGHT. A GRADUALLY INCREASING CIRRUS
SHIELD WILL BE THE ONE POSSIBLE DISRUPTION TO REALIZING THE FULL
POTENTIAL. OVERALL STILL LOOKING AT LOWS IN THE TEENS...A FEW
SINGLE DIGIT READINGS NOT OUT OF THE QUESTION IN THE COLDEST
LOCALES.
CONDITIONS INTO SUNDAY REMAIN DEFINED BY THE PRESENCE OF A COLD/DRY
ENVIRONMENT...LOW LEVEL FLOW FLIPPING TO EASTERLY WITH THE ARCTIC
HIGH SLOWLY EASING EASTWARD. HIGHS AGAIN IN THE 20S...EFFECTIVELY
CONTAINED BY A MORE CONCERTED INCREASE IN HIGH CLOUD. FOCUS INTO
SUNDAY EVENING/NIGHT THEN TURNS TO A WELL DEFINED PV ANOMALY WORKING
THROUGH THE TROUGH BASE. THIS WAVE WILL SHEAR INTO THE PREVAILING
SOUTHWESTERLIES ORIENTED FROM THE CENTRAL PLAINS INTO THE GREAT
LAKES THROUGH THE LATTER HALF OF THE WEEKEND. THIS PROCESS WILL
PROMPT TWO AREAS OF FOCUS...ONE WITHIN A WING OF EMERGING ISENTROPIC
ASCENT AND MOISTURE TRANSPORT ORIGINATING OUT OF THE WESTERN
GULF...AND A SECOND ACCOMPANYING THE PRIMARY REGION OF FORCED ASCENT
CONTAINED WITHIN THE MAIN HEIGHT FALL CENTER AND ALONG THE
DEVELOPING WEAK SURFACE WAVE AND FRONTAL CIRCULATION EJECTING OUT OF
THE PLAINS. THE OVERALL UPPER JET POSITIONING WOULD TEND TO DIRECT
THE BULK OF THE GULF ORIGINATING MOISTURE AND ATTENDANT WEAK ASCENT
TO OUR SOUTHEAST. IT REMAINS PLAUSIBLE FOR SOUTHERN SECTIONS OF
SOUTHEAST MICHIGAN TO RECEIVE A GLANCING SHOT ALONG THE WESTERN EDGE
SUNDAY EVENING. WEAK SURFACE WAVE THEN LIFTS THROUGH LOWER MICHIGAN
SUNDAY NIGHT...DISPLACED SOUTHEAST OF THE MAIN STRIPE OF DCVA AND
DEFORMATION FORCING SHIFTING FROM THE UPPER MS VALLEY INTO THE U.P.
THIS WILL LEAVE SE MICHIGAN UNDER A BROADER LOOKING PERIOD OF
FORCING...STILL SUFFICIENT TOWARD GENERATING A FEW HUNDREDTHS OF QPF
SUNDAY NIGHT. A SUB-FREEZING THERMAL PROFILE THROUGHOUT WILL
SUPPORT ALL SNOW...ALTHOUGH THE PROFILE WILL BE WARMING WITH
TIME...EFFECTIVELY REDUCING POTENTIAL SNOWFALL RATIOS.
A GENERAL EASTWARD MIGRATION OF THE MEAN LONGWAVE TROUGH WILL DIRECT
A SERIES SHORTWAVES OF SIBERIAN ORIGIN THROUGH THE GREAT LAKES
DURING THE EARLY AND MID WEEK PERIOD. THIS WILL RESULT IN AN
EXTENDED STRETCH OF WELL BELOW NORMAL TEMPERATURES AS ARCTIC AIR
TAKES FIRM RESIDENCE THROUGHOUT THE WEEK.
MARINE...
WESTERLY WINDS WILL DIMINISH SLIGHTLY TODAY AND TONIGHT AS THE
PRESSURE GRADIENT EASES BEHIND LOW PRESSURE LIFTING INTO QUEBEC.
THIS WILL RESULT IN A LOWER WAVE CONDITIONS THROUGH THIS TIME.
COLDER AIR MOVING ACROSS THE WATERS WILL MAINTAIN WIND SPEEDS IN
THE 15 TO 20 KNOT RANGE ACROSS NORTHERN PORTIONS OF LAKE HURON.
SLIGHT INCREASE IN WINDS EARLY SATURDAY WILL BRING GUSTS JUST SHY
OF GALES ACROSS NORTHERN LAKE HURON. STRONG HIGH PRESSURE WILL
THEN TAKE CONTROL SATURDAY NIGHT AND SUNDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SC
UPDATE.......SC
SHORT TERM...CB
LONG TERM....MR
MARINE.......MR
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1128 AM EST FRI DEC 6 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 332 AM EST FRI DEC 6 2013
COLD AIR IS EXPECTED TO REMAIN IN PLACE THROUGH THE WEEKEND. THERE
WILL BE SOME LAKE EFFECT SNOW SHOWERS THROUGH SATURDAY. NO
SIGNIFICANT ACCUMULATIONS ARE EXPECTED. MOST OF THE AREA SHOULD SEE
LIGHT SNOW ACCUMULATIONS LATE SUNDAY THROUGH MONDAY AS A WAVE OF LOW
PRESSURE MOVES THROUGH THE AREA.
COLDER AIR WILL MOVE IN DURING THE EARLY PORTION OF NEXT WEEK.
CONDITIONS LOOK A BIT MORE FAVORABLE FOR LAKE EFFECT SNOW
ACCUMULATIONS NEXT WEEK...ESPECIALLY ACROSS THE WESTERN HALF OF THE
AREA.
&&
.UPDATE...
ISSUED AT 1128 AM EST FRI DEC 6 2013
I UPDATED THE FORECAST TO SHOW HIGHER PROBABILITIES OF LIGHT SNOW
SHOWERS WEST OF US-131 BASED ON RADAR RETURNS...SURFACE OBS (BIV
1 1/2-4SM -SN/ MKG 2-4SM -SN)...LAKE ENHANCED IR IMAGE LOOPS AND
USING THE OMEGA AND RH FROM THE LATEST RAP MODEL IN THE 0-2KM
LAYER. THE LATEST RAP MODEL SUGGESTS THE AREA OF BEST LIFT WILL
SHIFT SOUTH THIS AFTERNOON FROM WHITEHALL TO SOUTH HAVEN NOW... TO
HOLLAND TO BENTON HARBOR BY MID AFTERNOON. INLAND EXPECT JUST
FLURRIES (I PUT FLURRIES IN THE GRIDS TOO). AS ALWAYS IN THESE
SITUATIONS EVEN THE HIGH RES MODELS ARE HAVING A PROBLEM
FORECASTING THIS TYPE OF SNOW SHOWER ACTIVITY.
I STILL EXPECT THE BETTER ACCUMULATIONS TONIGHT INTO SATURDAY SO I
UPDATED THOSE GRIDS TO SHOW HIGHER PROBABILITIES. STILL
ACCUMULATIONS SHOULD BE LESS THAN 2 INCHES IN MOST PLACES.
ELSWHERE AND OTHERWISE THE FORECAST IS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 332 AM EST FRI DEC 6 2013
THE MAIN FOCUS OF THE SHORT TERM PORTION OF THE FCST REMAINS LAKE
EFFECT TRENDS THROUGH THE PERIOD WITH COLD AIR EXPECTED TO REMAIN IN
PLACE. NO REAL CHANGES HAVE BEEN MADE WITH THE FCST AS MODELS ARE
SHOWING GOOD RUN TO RUN CONSISTENCY.
LAKE EFFECT HAS BEEN SLOW TO GET STARTED WITH THIS COLD AIR
MASS...AND THAT CONTINUES TO BE THE CASE THIS MORNING. SOME FLURRIES
ARE BEING REPORTED AT KCAD JUST NORTH OF THE CWFA...BUT NOTHING IN
THE CWFA AS OF 08Z THIS MORNING. THE LACK OF MOISTURE DEPTH AND LACK
OF LOW LEVEL CONVERGENCE UNDER FAIRLY ROBUST SUBSIDENCE WITH THE
ENTRANCE REGION OF THE STRONG UPPER JET IS OVERCOMING THE HEALTHY
OVER LAKE INSTABILITY.
WE DO EXPECT TO SEE A FEW SNOW SHOWERS DEVELOP TODAY. ONGOING CAA
WILL HELP A BIT TO LOWER THE DGZ INTO THE LIMITED MOISTURE LAYER A
BIT BETTER. THE AFOREMENTIONED LIMITING FACTORS WILL KEEP ANY SNOW
SHOWERS UNDER CONTROL TODAY. THE ONGOING CAA WILL LIMIT THE AMOUNT
OF WARMING FOR TEMPS TODAY. HIGHS SHOULD NOT CLIMB ABOVE THE UPPER
20S AFTER WE LOSE A FEW DEGREES THIS MORNING.
WE CONTINUE TO ANTICIPATE AN UPTICK IN LAKE EFFECT SNOW SHOWER
ACTIVITY FOR TONIGHT AND EARLY SAT MORNING. THIS UPTICK IS EXPECTED
TO BE THE RESULT OF A SHORT WAVE/PV ANOMALY CURRENTLY OVER NM THIS
MORNING LIFTING TO THE NE OVER THE AREA TONIGHT. INVERSION HEIGHTS
WILL BUMP UP TO AROUND 5K FEET OR SO. AT THE SAME TIME...A BIT OF
MID LEVEL MOISTURE WILL TRY TO HELP SNOW SHOWER GENERATION WITH A
SEEDER FEEDER TYPE OF SCENARIO. THERE WILL BE ABOUT 4-6K FT OF DRY
AIR IN BETWEEN THE LAYERS...SO IT IS NOT A GUARANTEE THIS WILL
ABSOLUTELY HELP. THE DGZ WILL BE SATURATED QUITE A BIT WHICH WILL
HELP FOR THE SNOW CAUSE. WNW FLOW FAVORED AREAS WILL SEE THE BEST
CHC OF SNOW SHOWERS AND SOME ACCUMULATIONS. LOW LEVEL CONVERGENCE IS
STILL LACKING...SO WE DO NOT EXPECT SNOW AMOUNTS TO GET OUT OF HAND.
WE WILL SEE THE LAKE EFFECT SNOW SHOWERS THEN GRADUALLY DIMINISH IN
COVERAGE AND INTENSITY DURING THE DAY ON SAT. THE NM SHORT WAVE WILL
EXIT THE AREA AND SUBSIDENCE WILL TAKE CONTROL ONCE AGAIN. INVERSION
HEIGHTS ARE EXPECTED TO LOWER TO AROUND 3K FEET...BEFORE LOW LEVEL
MOISTURE IS EXPECTED TO DISSIPATE WITH A STRONG ARCTIC SFC RIDGE
MOVING DIRECTLY OVERHEAD. THIS WILL ALLOW FOR A COLD SAT NIGHT WITH
SOME CLEARING LIKELY.
THE CLEARING AND BREAK IN THE SNOW SHOWERS WILL BE SHORT LIVED. WE
WILL SEE ADDITIONAL SHORT WAVE ENERGY EJECT OUT FROM THE WRN U.S.
TROUGH AND APPROACH THE AREA SUN AFTERNOON. SOME MOISTURE FROM THE
STRONG STORM SYSTEM EXPECTED ACROSS THE SE STATES WILL WRAP INTO
THIS WAVE AS IT IS PASSING ACROSS THE STATE. THE MOISTURE IS NOT
THAT RICH AS THE BEST MOISTURE WILL REMAIN WELL SE OF THE AREA WITH
THE MAIN BAROCLINIC/FRONTAL ZONE ACROSS THE SE PORTION OF THE
COUNTRY. FORCING IS LIMITED TOO THIS FAR NORTH WITH THE MAIN
ISENTROPIC ASCENT REMAINING WELL SOUTH AND EAST. THIS LOOKS LIKE A
LIGHT SNOW EVENT WHERE MOST OF THE AREA WILL SEE AN INCH OR TWO OF
SNOW ACCUMULATION.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 332 AM EST FRI DEC 6 2013
THE SYNOPTIC SYSTEM FOR SUNDAY NIGHT CONTINUES TO LOOK LESS
IMPRESSIVE WITH EACH MODEL RUN. WEAK/BAGGY SFC LOW PRESSURE PATTERN
PASSES ACROSS LOWER MI WITH ONLY AROUND ONE TENTH OF AN INCH OF QPF.
NO DECENT/AMPLIFIED SHORTWAVE IS PRESENT ALOFT...AND INSTEAD IT IS
JUST A SHEARED OUT/ELONGATED VORTICITY PATTERN.
THERE IS ALSO THE ISSUE OF A POTENTIAL MID LEVEL DRY SLOT SWEEPING
IN WHICH COULD LEAD TO MORE OF A LIGHT FREEZING RAIN/DRIZZLE THREAT
SUNDAY NIGHT RATHER THAN LIGHT SNOW. WILL KEEP LIKELY POPS FOR LIGHT
SNOW OVER THE ENTIRE AREA FOR NOW BUT IF THE TRENDS CONTINUE THEN
THE FREEZING PRECIP THREAT MAY NEED TO BE ADDED IN LATER FORECASTS.
COLD ADVECTION FOLLOWS ON MONDAY BEHIND THE WEAK EXITING SYSTEM BUT
THE REALLY COLD ARCTIC AIR DOES NOT ARRIVE UNTIL TUESDAY OR TUESDAY
NIGHT. IT IS THE CLIPPER SYSTEM TRACKING ACROSS LAKE SUPERIOR WHICH
BRINGS IN THE COLD AIR AND PERHAPS A BETTER RISK OF SOME
ACCUMULATING LAKE EFFECT SNOW. EVEN THIS IS QUESTIONABLE HOWEVER
SINCE THE CORE OF THE UPPER JET DOES NOT DIP SOUTH OF THE STATE AND
MOISTURE IS RATHER SHALLOW/LIMITED.
THE LAKE EFFECT SNOW SHOWER THREAT IS EXPECTED TO DIMINISH THURSDAY
AS SURFACE RIDGING BUILDS IN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 658 AM EST FRI DEC 6 2013
MVFR CIGS AROUND 2500 FT AND A FEW LIGHT LAKE EFFECT SNOW SHOWERS
ARE ANTICIPATED TODAY. FOR THE MOST PART NO SIGNIFICANT LENGTHY
REDUCTIONS TO VSBYS ARE EXPECTED... BUT THERE MAY BE TIMES WHEN IT
DIPS DOWN TO 4-6 MILES. LAN AND JXN PROBABLY WILL NOT SEE THE MVFR
CIGS AND FLURRIES TODAY... BUT THEY COULD SPREAD INLAND TONIGHT.
KMKG AND KAZO MAY SEE SOME BETTER SNOW SHOWERS DEVELOPING LATER
TONIGHT WHICH COULD LOWER VSBYS POTENTIALLY INTO IFR CATEGORY AT
TIMES. DID NOT INCLUDE THIS THREAT IN THE TAFS YET HOWEVER AS
CONFIDENCE IS CURRENTLY TOO LOW.
&&
.MARINE...
ISSUED AT 332 AM EST FRI DEC 6 2013
WE ARE EXTENDING THE SMALL CRAFT ADVISORY FOR THE ENTIRE NEARSHORE
THROUGH 06Z SUN WITH THIS FCST PACKAGE. WINDS WILL COME DOWN TO
AROUND 15 TO 20 KNOTS TODAY AND REMAIN THERE THROUGH SAT. THE
ONSHORE FLOW AND UNSTABLE CONDITIONS WITH THE COLD AIR COMING IN
OVER THE LAKE WILL KEEP WAVES ABOVE 4 FEET THROUGH SAT. THERE SHOULD
BE A BREAK SAT NIGHT AND EARLY SUN.
&&
.HYDROLOGY...
ISSUED AT 332 AM EST FRI DEC 6 2013
THE ONLY CONCERN WITH HYDROLOGY REMAINS THE THREAT FOR ICE
DEVELOPMENT OVER THE NEXT WEEK. ARCTIC COLD AIR EXPECTED OVER THE
AREA THROUGH MOST OF THE NEXT WEEK WILL HELP ICE DEVELOPMENT. AS THE
ICE DEVELOPS...WE WILL BE MONITORING THE POTENTIAL FOR ICE JAMS TO
FORM.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 1 AM EST SUNDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...NJJ
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
409 PM EST FRI DEC 6 2013
.SYNOPSIS...
A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE
TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TONIGHT INTO
EARLY SATURDAY MORNING...BRINGING MIXED AND FROZEN PRECIPITATION
TO THE AREA. HIGH PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE
RECENTLY ACTIVE EARLY SEASON WINTER WEATHER PATTERN ON SATURDAY
INTO SATURDAY NIGHT. CONFIDENCE CONTINUES TO INCREASE FOR A PERIOD
OF FROZEN AND FREEZING PRECIPITATION SUNDAY INTO EARLY MONDAY THAT
SHOULD EVENTUALLY CHANGE TO RAIN. AN ARCTIC FRONTAL PASSAGE EARLY
NEXT WEEK WILL DROP TEMPERATURES WELL BELOW NORMAL THROUGH THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 9 PM THIS EVENING/...
RADAR AND SATELLITE SHOW THE PRECIPITATION SHIELD MOVING TOWARD
OUR REGION. UPDATED HIGH RESOLUTION MODELS SHOW THE TREND FOR FAST
TRANSITION RAIN TO SNOW AND FAST PERIOD OF SNOW WITH A TENDENCY TO
HAVE HIGHER QPF AND SNOW AMOUNTS FARTHER SOUTH. SNOW COULD BE
HEAVIER THIS EVENING AND INTO EARLY TONIGHT FARTHER SOUTH THAN
EARLIER FORECASTS.
THERE SHOULD BE A PERIOD OF MODERATE TO HEAVY SNOW THIS EVENING
AND TO ABOUT MIDNIGHT IN CENTRAL AND WESTERN PA. SIGNIFICANT SNOW
IS LIKELY BEFORE 9 PM.
IN CENTRAL AREAS THE RAIN WILL RAPIDLY MIX WITH ICE PELLETS AND
FREEZING RAIN THEN TURN TO SNOW. MOST MODELS SHOW THE 0C CONTOUR
RAIN/SNOW LINE PROXY THROUGH STATE COLLEGE ABOUT 5 PM. THIS
FEATURE STALL BETWEEN STATE COLLEGE AND HARRISBURG UNTIL ABOUT
MIDNIGHT.
MOST OF CENTRAL AND NORTHERN PENNSYLVANIA SHOULD SEE SNOW BY 7 PM
WITH SOME MIX OF ICE PELLETS AND FREEZING RAIN FARTHER SOUTH
BEFORE IT TRANSITIONS TO ALL RAIN IN THE LOWER SUSQUEHANNA VALLEY.
SOUTHEASTERN AREAS WILL REMAIN RAIN THIS EVENING.KEY POINT IN
CENTRAL AND NORTH-CENTRAL PA IS RAPID RAIN TO SNOW TRANSITION THIS
EVENING...
&&
.SHORT TERM /9 PM THIS EVENING THROUGH SATURDAY NIGHT/...
KEY ISSUE IS PRECIPITATION SHOULD BE OVER WELL BEFORE SUNRISE...
BETWEEN ABOUT 9 PM AND 2 AM THERE WILL BE SOME MODERATE TO HEAVY
SNOW OVER MOST OF CENTRAL AND NORTHERN PENNSYLVANIA. THE SNOW
SHOULD LET UP A FEW HOURS AFTER MIDNIGHT. SREF AND GEFS HAVE
HEAVIER SNOW BAND NORTH OF THE 4KM RAP AND 4KM NAM. WARNINGS MAY
HAVE TO SLIDE SOUTH SHOULD UPDATED SREF/GEFS INDICATE A SIMILAR
TREND.
WE WENT WITH THE HIGHER PROBABILITY FORECAST.
RAIN AND SNOW WITH FREEZING RAIN WILL SAG SOUTHWARD. EXTREME
SOUTHEASTERN AREAS LIKE HARRISBURG AND YORK SHOULD REMAIN ALL RAIN
AND MAY END WITH A BRIEF PERIOD OF FZDZ SATURDAY MORNING.
SATURDAY WILL BE COLD BUT SHOULD BE MOSTLY PRECIPITATION FREE.
LEFT SOME POST FRONTAL NW FLOW SNOW SHOWERS IN WESTERN AND
NORTHWESTERN MOUNTAINS SATURDAY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AFTER A BRIEF RESPITE FROM THE ACTIVE EARLY-SEASON WINTER WEATHER
PATTERN...THE COMBINATION OF LOW-LEVEL COLD AIR ASSOCIATED WITH A
RETREATING ARCTIC SFC HIGH...A STRONG UPPER RIDGE OFF THE
SOUTHEAST COAST...AND A PERSISTENT MOIST SOUTHWESTERLY UPPER FLOW
WITH EMBEDDED WEAK SYSTEMS OPERATING ON AN INTENSE/TIGHT FRONTAL-
BAROCLINIC ZONE /RATHER THAN ONE CONCENTRATED IMPULSE/ WILL BRING
ANOTHER ROUND OF MIXED/WINTRY PRECIPITATION TO THE REGION SUNDAY-
MONDAY. THE FRONTAL ZONE AND AND STRONG UPPER JET WILL SHIFT OFF
THE COAST INTO THE MIDDLE OF THE WEEK...ALLOWING A VERY COLD
AIRMASS TO SPREAD INTO THE REGION FOR LATE IN THE PERIOD.
ALL SIGNS CONTINUE TO POINT TOWARD A CLASSIC OVERRUNNING MIXED
WINTRY PRECIP EVENT FOR SUNDAY-MONDAY...ALTHOUGH THERE ARE SOME
MODEL DIFFS WITH REGARDS TO THE TIMING AND NRN EXTENT OF THE
PRECIP SHIELD.
A 150 KT UPPER JET WILL SHIFT NORTHWARD AS WEAK IMPULSES EJECT
NORTHEASTWARD OUT OF THE DEEP WESTERN TROUGH...WITH PRECIPITATION
EXPANDING NORTHWARD ALONG AN INVERTED SFC TROUGH AXIS ACROSS THE
SOUTHEAST/TENNESSEE VALLEY INTO THE MIDDLE ATLANTIC STATES.
A SURGE OF INTENSE 850-700MB WARM AIR/THETA E/MOISTURE ADVECTION
WILL SPREAD QUICKLY NEWD BEHIND THE FAST SWLY FLOW ALOFT AND
OVERRUN A SHALLOW LAYER OF LLVL SUB-FREEZING AIR DRAINING SWD
ALONG THE ERN SLOPES OF THE APPLCHNS.
THE SYNOPTIC PATTERN LOOKS VERY CONDUCIVE FOR A PERIOD OF
FREEZING-TO-FROZEN PCPN /SN-PL-FZRA/ AS MSTR AND STG WAA ALOFT
FLOWS OVER THE TOP OF A SHALLOW SUB-FZG AIRMASS THAT SHOULD REMAIN
ENTRENCHED ALONG/E OF THE ALLEGHENIES VIA LLVL COLD AIR
DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY AGEO FLOW AND WET
BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM ENOUGH TO CHANGE
FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS AROUND MON AFTN BEFORE
THE ARCTIC COLD FRONT CROSSES THE REGION MON NGT. THE 06/12Z GEFS
MEAN SHOWS A HIGH PROBABILITY OF A FEW INCHES OF SNOW/SLEET ON THE
LEADING EDGE OF THE PRECIP SHIELD FOLLOWED BY POTENTIAL
SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE LAURELS/SCNTRL MTNS
INTO THE INTERIOR N-CNTRL PART OF THE CWA. WILL CONTINUE TO
HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE IS INCREASING IN
AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING GIVEN POTENTIAL
FOR ICE ACCUM >0.25 INCH.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
DETERIORATING FLYING CONDS ARE EXPECTED ACROSS CENTRAL PA THIS
AFTN/EVE...AS ANOTHER ROUND OF PRECIPITATION PUSHES BACK INTO THE
AREA. NRN AND WRN TAF SITES WILL LIKELY SEE A WINTRY MIX CHANGING TO
SNOW THIS EVENING...WITH RAIN CONTINUING FARTHER TO THE SOUTHEAST
/MDT AND LNS/.
THE PRECIP SHOULD GRADUALLY TAPER OFF OVERNIGHT...WITH EVEN MDT
AND LNS POSSIBLY SEEING A BRIEF CHANGEOVER TO SNOW BEFORE THE
PRECIP ENDS.
IMPROVING CONDS EXPECTED FOR SATURDAY...AS THE SYSTEM PULLS EAST
OF THE REGION. NORTHWEST FLOW DEVELOPS...AND WE SHOULD SEE A
RETURN TO VFR CONDS. UPSLOPING NW FLOW COULD DELAY THE IMPROVEMENT
FOR THE WRN TAF SITES /JST AND BFD/...BUT EVEN THEY SHOULD IMPROVE
AS THE DAY PROGRESSES.
THINGS REMAIN QUIET SAT NIGHT INTO EARLY SUNDAY...BEFORE THE NEXT
SYSTEM BRINGS LOWERING CIGS AND SNOW DEVELOPING SUNDAY AFTN. THE
SNOW IS EXPECTED TO CHANGE OVER TO A WINTRY MIX OR RAIN SUNDAY
NIGHT...BEFORE GRADUALLY TAPERING OFF MONDAY.
OUTLOOK...
SAT...BECOMING VFR CENTRAL/EASTERN AREAS...WITH LOWER CIGS
POSSIBLY LINGERING ACROSS THE NORTH AND WEST.
SUN...VFR WILL GIVE WAY TO MVFR/IFR AS THE NEXT ROUND OF WINTRY
PRECIP ARRIVES.
MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT.
TUE-WED...WEST TO NORTHWEST FLOW DEVELOPING. COLD WITH SCT -SHSN
NORTH AND WEST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM EST SATURDAY FOR PAZ019-
024>028-033>035-042-045-046-049>053.
WINTER STORM WARNING UNTIL 5 AM EST SATURDAY FOR PAZ004>006-
010>012-017-018-037-041.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...GRUMM/STEINBUGL
SHORT TERM...GRUMM/STEINBUGL
LONG TERM...STEINBUGL
AVIATION...EVANEGO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
119 PM EST FRI DEC 6 2013
.SYNOPSIS...
A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE
TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TODAY THROUGH
SATURDAY...BRINGING A CHANGEOVER TO MIXED AND FROZEN PRECIPITATION
TO THE AREA. HIGH PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE
RECENTLY ACTIVE EARLY SEASON WINTER WEATHER PATTERN ON SATURDAY.
CONFIDENCE IS STEADILY INCREASING FOR A PERIOD OF FROZEN AND
FREEZING PRECIPITATION SUNDAY INTO EARLY MONDAY THAT SHOULD
EVENTUALLY CHANGE TO RAIN. AN ARCTIC FRONTAL PASSAGE EARLY NEXT
WEEK WILL DROP TEMPERATURES WELL BELOW NORMAL THROUGH NEXT
WEDNESDAY.
&&
.NEAR TERM /UNTIL 9 PM THIS EVENING/...
RADAR AND SATELLITE SHOW THE PRECIPITATION SHIELD MOVING TOWARD
OUR REGION. UPDATED HIGH RESOLUTION MODELS SHOW THE TREND FOR FAST
TRANSITION RAIN TO SNOW AND FAST PERIOD OF SNOW WITH A TENDENCY TO
HAVE HIGHER QPF AND SNOW AMOUNTS FARTHER SOUTH. SNOW COULD BE
HEAVIER THIS EVENING AND INTO EARLY TONIGHT FARTHER SOUTH THAN
EARLIER FORECASTS.
THERE SHOULD BE A PERIOD OF MODERATE TO HEAVY SNOW THIS EVENING
AND TO ABOUT MIDNIGHT IN CENTRAL AND WESTERN PA. SIGNIFICANT SNOW
IS LIKELY BEFORE 9 PM.
IN CENTRAL AREAS THE RAIN WILL RAPIDLY MIX WITH ICE PELLETS AND
FREEZING RAIN THEN TURN TO SNOW. MOST MODELS SHOW THE 0C CONTOUR
RAIN/SNOW LINE PROXY THROUGH STATE COLLEGE ABOUT 5 PM. THIS
FEATURE STALL BETWEEN STATE COLLEGE AND HARRISBURG UNTIL ABOUT
MIDNIGHT.
MOST OF CENTRAL AND NORTHERN PENNSYLVANIA SHOULD SEE SNOW BY 7 PM
WITH SOME MIX OF ICE PELLETS AND FREEZING RAIN FARTHER SOUTH
BEFORE IT TRANSITIONS TO ALL RAIN IN THE LOWER SUSQUEHANNA VALLEY.
SOUTHEASTERN AREAS WILL REMAIN RAIN THIS EVENING.
KEY POINT IN CENTRAL AND NORTH-CENTRAL PA IS RAPID RAIN TO SNOW
TRANSITION THIS EVENING...
&&
.SHORT TERM /9 PM THIS EVENING THROUGH 6 PM SATURDAY/...
KEY ISSUE IS PRECIPITATION SHOULD BE OVER WELL BEFORE SUNRISE...
BETWEEN ABOUT 9 PM AND 2 AM THERE WILL BE SOME MODERATE TO HEAVY
SNOW OVER MOST OF CENTRAL AND NORTHERN PENNSYLVANIA. THE SNOW
SHOULD LET UP A FEW HOURS AFTER MIDNIGHT. SREF AND GEFS HAVE
HEAVIER SNOW BAND NORTH OF THE 4KM RAP AND 4KM NAM. WARNINGS MAY
HAVE TO SLIDE SOUTH SHOULD UPDATED SREF/GEFS INDICATE A SIMILAR
TREND.
WE WENT WITH THE HIGHER PROBABILITY FORECAST.
RAIN AND SNOW WITH FREEZING RAIN WILL SAG SOUTHWARD. EXTREME
SOUTHEASTERN AREAS LIKE HARRISBURG AND YORK SHOULD REMAIN ALL RAIN
AND MAY END WITH A BRIEF PERIOD OF FZDZ SATURDAY MORNING.
SATURDAY WILL BE COLD BUT SHOULD BE MOSTLY PRECIPITATION FREE.
LEFT SOME POST FRONTAL NW FLOW SNOW SHOWERS IN WESTERN AND
NORTHWESTERN MOUNTAINS SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THERE IS THE POTENTIAL FOR SIGNIFICANT FREEZING RAIN LATE
SUNDAY AND EARLY MONDAY IN THE SOUTHWEST MOUNTAINS....
PREVIOUS DISCUSSION...1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE
OVER THE UPPER MIDWEST SATURDAY WILL MIGRATE EASTWARD INTO THE
NORTHERN MID- ATLANTIC STATES BY SUNDAY MORNING...SETTING THE
STAGE FOR WHAT APPEARS TO BE A CLASSIC OVERRUNNING MIXED PRECIP
EVENT FOR LATER SUNDAY INTO MONDAY.
05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES
INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING
FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS.
THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN
CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES
SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN
NEW ENGLAND.
DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH
THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM
AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A
BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR
ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN
LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS
MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG
AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES
VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY
AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM
ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS
AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION
MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW
INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD
FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE
LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA.
WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE
IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING
ASSUMING MOD-HVY ICING VIA FZRA.
IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE
REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW
NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD
CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW
COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE
INTO SW NY.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
DETERIORATING FLYING CONDS ARE EXPECTED ACROSS CENTRAL PA THIS
AFTN/EVE...AS ANOTHER ROUND OF PRECIPITATION PUSHES BACK INTO THE
AREA. NRN AND WRN TAF SITES WILL LIKELY SEE A WINTRY MIX CHANGING TO
SNOW THIS EVENING...WITH RAIN CONTINUING FARTHER TO THE SOUTHEAST
/MDT AND LNS/.
THE PRECIP SHOULD GRADUALLY TAPER OFF OVERNIGHT...WITH EVEN MDT
AND LNS POSSIBLY SEEING A BRIEF CHANGEOVER TO SNOW BEFORE THE
PRECIP ENDS.
IMPROVING CONDS EXPECTED FOR SATURDAY...AS THE SYSTEM PULLS EAST
OF THE REGION. NORTHWEST FLOW DEVELOPS...AND WE SHOULD SEE A
RETURN TO VFR CONDS. UPSLOPING NW FLOW COULD DELAY THE IMPROVEMENT
FOR THE WRN TAF SITES /JST AND BFD/...BUT EVEN THEY SHOULD IMPROVE
AS THE DAY PROGRESSES.
THINGS REMAIN QUIET SAT NIGHT INTO EARLY SUNDAY...BEFORE THE NEXT
SYSTEM BRINGS LOWERING CIGS AND SNOW DEVELOPING SUNDAY AFTN. THE
SNOW IS EXPCETED TO CHANGE OVER TO A WINTRY MIX OR RAIN SUNDAY
NIGHT...BEFORE GRADUALLY TAPERING OFF MONDAY.
OUTLOOK...
SAT...BECOMING VFR CENTRAL/EASTERN AREAS...WITH LOWER CIGS
POSSIBLY LINGERING ACROSS THE NORTH AND WEST.
SUN...VFR WILL GIVE WAY TO MVFR/IFR AS THE NEXT ROUND OF WINTRY
PRECIP ARRIVES.
MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT.
TUE-WED...WEST TO NORTHWEST FLOW DEVELOPING. COLD WITH SCT -SNSH
NORTH AND WEST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM EST
SATURDAY FOR PAZ019-024>028-033>035-042-045-046-049>053.
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 AM EST
SATURDAY FOR PAZ004>006-010>012-017-018-037-041.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...GRUMM/STEINBUGL
SHORT TERM...GRUMM/STEINBUGL
LONG TERM...STEINBUGL
AVIATION...EVANEGO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1239 PM EST FRI DEC 6 2013
.SYNOPSIS...
A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE
TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TODAY THROUGH
SATURDAY...BRINGING A CHANGEOVER TO MIXED AND FROZEN PRECIPITATION
TO THE AREA. HIGH PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE
RECENTLY ACTIVE EARLY SEASON WINTER WEATHER PATTERN ON SATURDAY.
CONFIDENCE IS STEADILY INCREASING FOR A PERIOD OF FROZEN AND
FREEZING PRECIPITATION SUNDAY INTO EARLY MONDAY THAT SHOULD
EVENTUALLY CHANGE TO RAIN. AN ARCTIC FRONTAL PASSAGE EARLY NEXT
WEEK WILL DROP TEMPERATURES WELL BELOW NORMAL THROUGH NEXT
WEDNESDAY.
&&
.NEAR TERM /UNTIL 9 PM THIS EVENING/...
RADAR AND SATELLITE SHOW THE PRECIPITATION SHIELD MOVING TOWARD
OUR REGION. UPDATED HIGH RESOLUTION MODELS SHOW THE TREND FOR FAST
TRANSITION RAIN TO SNOW AND FAST PERIOD OF SNOW WITH A TENDENCY TO
HAVE HIGHER QPF AND SNOW AMOUNTS FARTHER SOUTH. SNOW COULD BE
HEAVIER THIS EVENING AND INTO EARLY TONIGHT FARTHER SOUTH THAN
EARLIER FORECASTS.
THERE SHOULD BE A PERIOD OF MODERATE TO HEAVY SNOW THIS EVENING
AND TO ABOUT MIDNIGHT IN CENTRAL AND WESTERN PA. SIGNIFICANT SNOW
IS LIKELY BEFORE 9 PM.
IN CENTRAL AREAS THE RAIN WILL RAPIDLY MIX WITH ICE PELLETS AND
FREEZING RAIN THEN TURN TO SNOW. MOST MODELS SHOW THE 0C CONTOUR
RAIN/SNOW LINE PROXY THROUGH STATE COLLEGE ABOUT 5 PM. THIS
FEATURE STALL BETWEEN STATE COLLEGE AND HARRISBURG UNTIL ABOUT
MIDNIGHT.
MOST OF CENTRAL AND NORTHERN PENNSYLVANIA SHOULD SEE SNOW BY 7 PM
WITH SOME MIX OF ICE PELLETS AND FREEZING RAIN FARTHER SOUTH
BEFORE IT TRANSITIONS TO ALL RAIN IN THE LOWER SUSQUEHANNA VALLEY.
SOUTHEASTERN AREAS WILL REMAIN RAIN THIS EVENING.
KEY POINT IN CENTRAL AND NORTH-CENTRAL PA IS RAPID RAIN TO SNOW
TRANSITION THIS EVENING...
&&
.SHORT TERM /9 PM THIS EVENING THROUGH 6 PM SATURDAY/...
...KEY ISSUE IS PRECIPITATION SHOULD BE OVER WELL BEFORE SUNRISE...
BETWEEN ABOUT 9 PM AND 2 AM THERE WILL BE SOME MODERATE TO HEAVY
SNOW OVER MOST OF CENTRAL AND NORTHERN PENNSYLVANIA. THE SNOW
SHOULD LET UP A FEW HOURS AFTER MIDNIGHT. SREF AND GEFS HAVE
HEAVIER SNOW BAND NORTH OF THE 4KM RAP AND 4KM NAM. WARNINGS MAY
HAVE TO SLIDE SOUTH SHOULD UPDATED SREF/GEFS INDICATE A SIMILAR
TREND.
WE WENT WITH THE HIGHER PROBABILITY FORECAST.
RAIN AND SNOW WITH FREEZING RAIN WILL SAG SOUTHWARD. EXTREME
SOUTHEASTERN AREAS LIKE HARRISBURG AND YORK SHOULD REMAIN ALL RAIN
AND MAY END WITH A BRIEF PERIOD OF FZDZ SATURDAY MORNING.
SATURDAY WILL BE COLD BUT SHOULD BE MOSTLY PRECIPITATION FREE.
LEFT SOME POST FRONTAL NW FLOW SNOW SHOWERS IN WESTERN AND
NORTHWESTERN MOUNTAINS SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THERE IS THE POTENTIAL FOR SIGNIFICANT FREEZING RAIN LATE
SUNDAY AND EARLY MONDAY IN THE SOUTHWEST MOUNTAINS....
PREVIOUS DISCUSSION...1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE
OVER THE UPPER MIDWEST SATURDAY WILL MIGRATE EASTWARD INTO THE
NORTHERN MID- ATLANTIC STATES BY SUNDAY MORNING...SETTING THE
STAGE FOR WHAT APPEARS TO BE A CLASSIC OVERRUNNING MIXED PRECIP
EVENT FOR LATER SUNDAY INTO MONDAY.
05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES
INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING
FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS.
THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN
CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES
SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN
NEW ENGLAND.
DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH
THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM
AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A
BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR
ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN
LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS
MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG
AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES
VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY
AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM
ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS
AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION
MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW
INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD
FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE
LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA.
WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE
IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING
ASSUMING MOD-HVY ICING VIA FZRA.
IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE
REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW
NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD
CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW
COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE
INTO SW NY.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
A SHALLOW FRONTAL BOUNDARY BROUGHT AN END TO MOST OF THE
PRECIPITATION ACROSS THE REGION THIS MORNING. MOST VFR AND MVFR
CONDITIONS FOR THE NEXT FEW HOURS.
SNOW WILL MOVE INTO NORTHWESTERN AREAS THIS AFTERNOON AND LOWER
CEILINGS AND HEIGHTS. RAIN AND SNOW WILL MOVE INTO CENTRAL AREAS
IN THE 19 TO 22Z TIME-FRAME LOWERING CEILINGS AND HEIGHTS IN THAT
REGION. RAIN WILL MOVE INTO SOUTHERN REGIONS.
SHOULD BE MOSTLY IFR WITH AREAS OF LIFR IN SNOW AND RAIN.
THERE WILL BE A RAPID CHANGE OVER TO ALL SNOW IN CENTRAL AREAS
FROM ABOUT KAOO-KUNV-KIPT THIS EVENING.
THE PRECIPITATION SHOULD END RAPIDLY AFTER MIDNIGHT WITH A RETURN
TO MOSTLY VFR ON SATURDAY WITH SOME AREAS OF SNOW SHOWERS IN THE
WESTERN MOUNTAINS.
OUTLOOK...
FRI...VFR/MVFR SOME RAIN SE. AFTERNOON-EVEN...IFR IN SNOW/WINTRY
MIX AND RAIN.
SAT...MVFR SNOW SHOWERS IN THE MOUNTAINS. VFR IN CENTRAL/EASTERN
AREAS.
SUN...VFR WILL GIVE WAY TO IFR AS A WINTER STORM RAPIDLY SWEEPS
INTO THE REGION SUNDAY INTO SUNDAY NIGHT.
MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM EST
SATURDAY FOR PAZ019-024>028-033>035-042-045-046-049>053.
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 AM EST
SATURDAY FOR PAZ004>006-010>012-017-018-037-041.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...GRUMM/STEINBUGL
SHORT TERM...GRUMM/STEINBUGL
LONG TERM...STEINBUGL
AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1115 AM EST FRI DEC 6 2013
.SYNOPSIS...
A SERIES OF LOW PRESSURE WAVES WILL TRACK NORTHEAST FROM THE
TENNESSEE VALLEY ACROSS THE MID-ATLANTIC STATES TODAY THROUGH
SATURDAY...BRINGING A CHANGEOVER TO MIXED AND FROZEN PRECIPITATION
TO THE AREA. HIGH PRESSURE WILL PROVIDE A BRIEF RESPITE IN THE
RECENTLY ACTIVE EARLY SEASON WINTER WEATHER PATTERN ON SATURDAY.
CONFIDENCE IS STEADILY INCREASING FOR A PERIOD OF FROZEN AND
FREEZING PRECIPITATION SUNDAY INTO EARLY MONDAY THAT SHOULD
EVENTUALLY CHANGE TO RAIN. AN ARCTIC FRONTAL PASSAGE EARLY NEXT
WEEK WILL DROP TEMPERATURES WELL BELOW NORMAL THROUGH NEXT
WEDNESDAY.
&&
.NEAR TERM /UNTIL 9 PM THIS EVENING/...
AN ENHANCED AREA OF ENHANCED CLOUDS AND LIGHT RAIN WILL MOVE
ACROSS SOUTHEASTERN PA. A SHALLOW FRONTAL BOUNDARY OVER THE REGION
IS SLOWLY PUSHING COLD AIR IN FROM NORTHWEST TO SOUTH EAST.
TEMPERATURES ARE BELOW FREEZING IN NW PA AND IN THE 40S IN THE
SOUTHEAST. THE 850 MB ZERO ISOTHERM IS IN NW PA. FRONTAL ZONE AT
850 AND A WAVE TO THE WEST WILL PRODUCE SNOW...HEAVY SNOW...SOME
ICE...AND RAIN OVER THE STATE IN THE NEXT 18 HOURS.
THE MAIN PLAYER IS REALLY A LARGE ANTICYCLONE TO THE WEST AND COLD
AIR. THE "STORM" IS REALLY JUST A STRONG FRONTAL ZONE.
THE SREF AND GEFS SUGGEST SNOW WILL MOVE INTO NORTHWESTERN PA THIS
AFTERNOON AND LATER THIS AFTERNOON RAIN WILL MOVE INTO CENTRAL PA.
A SNOW-BAND IS EVOLVING OVER OHIO. THE RAP AND 4KM NAM SUGGEST THE
HEAVIEST SNOW COULD BE A BIT MORE SOUTH THAN THE 16KM SREF AND
55KM GEFS.
THERE SHOULD BE A PERIOD OF MODERATE TO HEAVY SNOW THIS EVENING
AND TO ABOUT MIDNIGHT IN NORTHWESTERN PA. SIGNIFICANT SNOW IS
LIKELY BEFORE 9 PM.
IN CENTRAL AREAS THE RAIN WILL RAPIDLY MIX WITH ICE PELLETS AND
FREEZING RAIN THEN TURN TO SNOW. MOST MODELS SHOW THE 0C CONTOUR
RAIN/SNOW LINE PROXY THROUGH STATE COLLEGE ABOUT 5 PM. THIS
FEATURE STALL BETWEEN STATE COLLEGE AND HARRISBURG UNTIL ABOUT
MIDNIGHT.
MOST OF CENTRAL AND NORTHERN PENNSYLVANIA SHOULD SEE SNOW BY 7 PM
WITH SOME MIX OF ICE PELLETS AND FREEZING RAIN FARTHER SOUTH
BEFORE IT TRANSITIONS TO ALL RAIN IN THE LOWER SUSQUEHANNA VALLEY.
SOUTHEASTERN AREAS WILL REMAIN RAIN THIS EVENING.
KEY POINT IN CENTRAL AND NORTH-CENTRAL PA IS RAPID RAIN TO SNOW
TRANSITION THIS EVENING...
&&
.SHORT TERM /9 PM THIS EVENING THROUGH 6 PM SATURDAY/...
BETWEEN ABOUT 9 PM AND 2 AM THERE WILL BE SOME MODERATE TO HEAVY
SNOW OVER MOST OF CENTRAL AND NORTHERN PENNSYLVANIA. THE SNOW
SHOULD LET UP A FEW HOURS AFTER MIDNIGHT. SREF AND GEFS HAVE
HEAVIER SNOW BAND NORTH OF THE 4KM RAP AND 4KM NAM. WARNINGS MAY
HAVE TO SLIDE SOUTH SHOULD UPDATED SREF/GEFS INDICATE A SIMILAR TREND.
WE WENT WITH THE HIGHER PROBABILITY FORECAST.
RAIN AND SNOW WITH FREEZING RAIN WILL SAG SOUTHWARD. EXTREME
SOUTHEASTERN AREAS LIKE HARRISBURG AND YORK SHOULD REMAIN ALL RAIN
AND MAY END WITH A BRIEF PERIOD OF FZDZ SATURDAY MORNING.
THE MODELS SUGGEST THE PRECIPITATION IS WELL TO OUR EAST A FEW
HOURS EITHER SIDE OF ABOUT 7 AM. SATURDAY WILL BE COLD BUT SHOULD
BE MOSTLY PRECIPITATION FREE.
LEFT SOME POST FRONTAL NW FLOW SNOW SHOWERS IN WESTERN AND
NORTHWESTERN MOUNTAINS SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THERE IS THE POTENTIAL FOR SIGNIFICANT FREEZING RAIN LATE
SUNDAY AND EARLY MONDAY IN THE SOUTHWEST MOUNTAINS....
PREVIOUS DISCUSSION...1040+ MB MODIFIED ARCTIC SFC HIGH PRESSURE
OVER THE UPPER MIDWEST SATURDAY WILL MIGRATE EASTWARD INTO THE
NORTHERN MID- ATLANTIC STATES BY SUNDAY MORNING...SETTING THE
STAGE FOR WHAT APPEARS TO BE A CLASSIC OVERRUNNING MIXED PRECIP
EVENT FOR LATER SUNDAY INTO MONDAY.
05/12Z DETERMINISTIC MODEL AND ENSEMBLE GUIDANCE SHOWS LOW PRES
INITIALLY DEVELOPING ALONG AN INVERTED SFC TROUGH AXIS EXTENDING
FROM THE LWR MS/TN VLY NEWD UP THE WEST-SIDE OF THE APPALACHIANS.
THE MAIN LOW SHOULD LIFT NWD THRU THE OH VLY/GRT LKS INTO SERN
CANADA ON DAYS 5-6. MEANWHILE A SECONDARY/WEAKER AREA OF LOW PRES
SHOULD FORM NEAR THE VA/NC COAST AND TRACK NNEWD JUST OFFSHORE SRN
NEW ENGLAND.
DOWNSTREAM FROM A VIGOROUS MID/UPPER LEVEL TROUGH DIGGING THROUGH
THE FOUR CORNERS/SRN ROCKIES...A SURGE OF INTENSE 850-700MB WARM
AIR/THETA E/MOISTURE ADVECTION WILL SPREAD QUICKLY NEWD BEHIND A
BROAD SWLY FLOW ALOFT AND OVERRUN A RETREATING COLD SECTOR
ASSOCIATED WITH THE RETREATING ARCTIC HIGH. THE SYNOPTIC PATTERN
LOOKS VERY CONDUCIVE FOR A PERIOD OF FREEZING-TO-FROZEN PCPN AS
MSTR AND STG WAA ALOFT FLOWS OVER THE TOP OF A SHALLOW SUB-FZG
AIRMASS THAT SHOULD REMAIN ENTRENCHED ALONG/E OF THE ALLEGHENIES
VIA LLVL COLD AIR DAMMING/SFC PRES CHANNELING...ENHANCED BY NELY
AGEO FLOW AND WET BULB EFFECTS. SFC-850MB TEMPS ARE FCST TO WARM
ENOUGH TO CHANGE FREEZING PTYPES TO PLAIN RAIN IN MOST AREAS
AROUND MON AFTN BEFORE THE ARCTIC COLD FRONT CROSSES THE REGION
MON NGT. THE 12Z GEFS MEAN SHOWS A HIGH PROBABILITY OF A FEW
INCHES OF SNOW/SLEET ON THE LEADING EDGE OF THE PRECIP SHIELD
FOLLOWED BY POTENTIAL SIGNIFICANT ICE ACCUMS ESPECIALLY FROM THE
LAURELS/SCNTRL MTNS INTO THE INTERIOR N-CNTRL PART OF THE CWA.
WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HWO BUT CONFIDENCE
IS INCREASING IN AT LEAST AN ADVISORY TYPE EVENT...IF NOT WARNING
ASSUMING MOD-HVY ICING VIA FZRA.
IN THE WAKE OF THIS SYSTEM...A VERY COLD PATTERN SHOULD GRIP THE
REGION THRU THE MIDDLE OF NEXT WEEK WITH TEMPERATURES WELL BELOW
NORMAL. SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE COLD
CYC FLOW ALOFT ALTHOUGH THE LLVL WINDS MAY HAVE TOO MUCH OF A SW
COMPNT WHICH WOULD ORIENT BANDS MORE ALONG THE LAKE ERIE SHORE
INTO SW NY.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
A SHALLOW FRONTAL BOUNDARY BROUGHT AN END TO MOST OF THE
PRECIPITATION ACROSS THE REGION THIS MORNING. MOST VFR AND MVFR
CONDITIONS FOR THE NEXT FEW HOURS.
SNOW WILL MOVE INTO NORTHWESTERN AREAS THIS AFTERNOON AND LOWER
CEILINGS AND HEIGHTS. RAIN AND SNOW WILL MOVE INTO CENTRAL AREAS
IN THE 19 TO 22Z TIME-FRAME LOWERING CEILINGS AND HEIGHTS IN THAT
REGION. RAIN WILL MOVE INTO SOUTHERN REGIONS.
SHOULD BE MOSTLY IFR WITH AREAS OF LIFR IN SNOW AND RAIN.
THERE WILL BE A RAPID CHANGE OVER TO ALL SNOW IN CENTRAL AREAS
FROM ABOUT KAOO-KUNV-KIPT THIS EVENING.
THE PRECIPITATION SHOULD END RAPIDLY AFTER MIDNIGHT WITH A RETURN
TO MOSTLY VFR ON SATURDAY WITH SOME AREAS OF SNOW SHOWERS IN THE
WESTERN MOUNTAINS.
OUTLOOK...
FRI...VFR/MVFR SOME RAIN SE. AFTERNOON-EVEN...IFR IN SNOW/WINTRY
MIX AND RAIN.
SAT...MVFR SNOW SHOWERS IN THE MOUNTAINS. VFR IN CENTRAL/EASTERN
AREAS.
SUN...VFR WILL GIVE WAY TO IFR AS A WINTER STORM RAPIDLY SWEEPS
INTO THE REGION SUNDAY INTO SUNDAY NIGHT.
MON...WIDESPREAD MVFR/IFR ASSOCIATED WITH A PASSING COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM EST
SATURDAY FOR PAZ019-024>028-033>035-042-045-046-049>053.
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 AM EST
SATURDAY FOR PAZ004>006-010>012-017-018-037-041.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...GRUMM/STEINBUGL
SHORT TERM...GRUMM/STEINBUGL
LONG TERM...STEINBUGL
AVIATION...GRUMM