Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/25/15
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
946 AM PST MON FEB 23 2015
.SYNOPSIS...AN UPPER LEVEL SYSTEM OVER THE REGION WILL RESULT IN A
SLIGHT CHANCE OF SHOWERS AND EMBEDDED THUNDERSTORMS OVER PORTIONS
OF MONTEREY AND SAN BENITO COUNTIES THIS AFTERNOON. DRY AND MILD
WEATHER WILL RETURN TUESDAY AND PERSIST THROUGH MIDWEEK, THEN A
POSSIBLE PATTERN CHANGE WILL POTENTIALLY BRING PRECIPITATION BACK
TO THE REGION BY THE END OF THE WEEK.
&&
.DISCUSSION...AS OF 8:50 AM PST MONDAY...UPPER LEVEL LOW CONTINUES
TO ROTATE OFF TO OUR SOUTHEAST WITH LIMITED INSTABILITY AND MOISTURE
FORECAST TO BE ACROSS SAN BENITO AND INTERIOR MONTEREY COUNTY
THROUGH THE DAY. LATEST RUN OF THE HRRR SHOWS A FEW SHOWERS
POPPING UP AROUND NOON AND CONTINUING TO ABOUT SUNSET. WILL ALSO
KEEP A MENTION OF THUNDERSTORMS GOING AS WELL. WINDS ARE STILL
LOCALLY GUSTY OVER THE NORTH AND EAST HILLS ALTHOUGH SPEEDS SHOULD
CONTINUE TO DIMINISH THROUGH THE DAY.
OUTSIDE OF THOSE ISSUES...QUIET WEATHER ACROSS OUR CWA WITH HIGHS
GENERALLY IN THE 60S. CURRENT FORECAST APPEARS ON TRACK SO NO
MAJOR UPDATES PLANNED AT THIS TIME.
.PREVIOUS DISCUSSION...GENERALLY CLEAR SKIES ACROSS THE REGION
THIS MORNING AS A COOL...DRY AIR MASS REMAINS ALOFT. NORTHERLY
WINDS CONTINUE TO BE BREEZY WITH GUSTS OF 40 TO 50 MPH IN THE MOST
EXPOSED LOCATIONS IN THE HIGHER ELEVATIONS ACROSS THE NORTH BAY
AND EAST BAY. THIS HAS RESULTED IN A GOOD AMOUNT OF MIXING AND
TEMPERATURES GENERALLY REMAIN IN THE 50S IN MOST VALLEY LOCATIONS
ACROSS THE NORTH. EXPECTING THESE WIND SPEEDS TO PERSIST THROUGH
THE MORNING HOURS AND WILL KEEP THE WIND ADVISORY IN EFFECT UNTIL
10 AM PST. AS THE PRESSURE GRADIENT RELAXES...WIND SPEEDS WILL
DIMINISH SOME BY THIS AFTERNOON.
THE MID/UPPER LEVEL SYSTEM THAT BROUGHT SCATTERED SHOWERS AND A
FEW THUNDERSTORMS TO THE REGION YESTERDAY CONTINUES TO BE
POSITIONED OVER CENTRAL CALIFORNIA AND NEVADA AT THIS HOUR.
LINGERING MOISTURE COMBINED WITH MID/UPPER LEVEL SUPPORT WILL
RESULT IN ISOLATED SHOWERS AND THUNDERSTORMS AGAIN OVER MONTEREY
AND SAN BENITO COUNTIES THIS AFTERNOON. HOWEVER...SHOWER ACTIVITY
IS EXPECTED TO BE LESS WIDESPREAD TODAY WITH DRIER AIR WRAPPING
AROUND THE WESTERN PERIPHERY OF THE UPPER LOW. RAIN CHANCES WILL
COME TO AN END BY LATE THIS EVENING AS THE UPPER LEVEL FEATURE
EJECTS TOWARD THE DESERT SOUTHWEST ON TUESDAY. MEANWHILE...THE
UPPER LEVEL RIDGE OFF OF THE WEST COAST WILL RESULT IN DRY
WEATHER CONDITIONS AND A SLIGHT WARMING TREND THROUGH AT LEAST
THURSDAY NIGHT.
THE FORECAST MODELS CONTINUE TO DEPICT A MID/UPPER LEVEL TROUGH
DROPPING OUT OF THE GULF OF ALASKA LATE THIS WEEK THAT WILL THEN
SLIDE DOWN THE WEST COAST THIS WEEKEND. AS A RESULT...WILL
MAINTAIN PRECIPITATION CHANCES OVER THE NORTH BAY ON FRIDAY AND
ACROSS MUCH OF THE REGION INTO SATURDAY NIGHT. WHILE CONFIDENCE
HAS INCREASED SLIGHTLY FOR SOME SORT OF A PATTERN CHANGE...THERE
REMAINS INCONSISTENCY AMONG THE MEDIUM RANGE MODELS LATE IN THE
FORECAST PERIOD.
&&
.AVIATION...AS OF 9:45 AM PST MONDAY...DRY NORTHERLY FLOW WILL
CONTINUE ACROSS THE REGION THROUGH TUESDAY...RESULTING IN VFR
CONDITIONS AT ALL TERMINALS. LOCAL GUSTY NORTH TO NORTHEAST WINDS
ON MONDAY MORNING WILL GRADUALLY TAPER OFF MONDAY AFTERNOON AND
EVENING.
VICINITY OF KSFO...VFR. LIGHT TO MODERATE NORTH TO NORTHEAST WINDS
THROUGH MID AFTERNOON TURNING TO LIGHT NORTHWEST BY LATE AFTERNOON.
KSFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY AREA TERMINALS...VFR. LIGHT WINDS.
&&
.MARINE...AS OF 3:59 AM PST MONDAY...HIGH PRESSURE WILL CONTINUE
OVER THE GREAT BASIN AND NORTHERNMOST CALIFORNIA TODAY AND
TONIGHT. THIS WILL RESULT IN A LIGHT TO MODERATE NORTHERLY WIND.
WINDS WILL BECOME NORTHWESTERLY OVER THE COASTAL WATERS BY ON
TUESDAY. A LOW PRESSURE AREA OVER THE GULF OF ALASKA WILL MOVE TO
THE BAY AREA FRIDAY BRINGING WITH IT A CHANCE OF SHOWERS.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...SF BAY NORTH OF THE BAY BRIDGE UNTIL 3 PM
&&
$$
PUBLIC FORECAST: BELL/RGASS
AVIATION: DYKEMA
MARINE: CANEPA
VISIT US AT WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSBAYAREA
WWW.TWITTER.COM/NWSBAYAREA
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
903 AM PST MON FEB 23 2015
.SYNOPSIS...AN UPPER LEVEL SYSTEM OVER THE REGION WILL RESULT IN A
SLIGHT CHANCE OF SHOWERS AND EMBEDDED THUNDERSTORMS OVER PORTIONS
OF MONTEREY AND SAN BENITO COUNTIES THIS AFTERNOON. DRY AND MILD
WEATHER WILL RETURN TUESDAY AND PERSIST THROUGH MIDWEEK, THEN A
POSSIBLE PATTERN CHANGE WILL POTENTIALLY BRING PRECIPITATION BACK
TO THE REGION BY THE END OF THE WEEK.
&&
.DISCUSSION...AS OF 8:50 AM PST MONDAY...UPPER LEVEL LOW CONTINUES
TO ROTATE OFF TO OUR SOUTHEAST WITH LIMITED INSTABILITY AND MOISTURE
FORECAST TO BE ACROSS SAN BENITO AND INTERIOR MONTEREY COUNTY
THROUGH THE DAY. LATEST RUN OF THE HRRR SHOWS A FEW SHOWERS
POPPING UP AROUND NOON AND CONTINUING TO ABOUT SUNSET. WILL ALSO
KEEP A MENTION OF THUNDERSTORMS GOING AS WELL. WINDS ARE STILL
LOCALLY GUSTY OVER THE NORTH AND EAST HILLS ALTHOUGH SPEEDS SHOULD
CONTINUE TO DIMINISH THROUGH THE DAY.
OUTSIDE OF THOSE ISSUES...QUIET WEATHER ACROSS OUR CWA WITH HIGHS
GENERALLY IN THE 60S. CURRENT FORECAST APPEARS ON TRACK SO NO
MAJOR UPDATES PLANNED AT THIS TIME.
.PREVIOUS DISCUSSION...GENERALLY CLEAR SKIES ACROSS THE REGION
THIS MORNING AS A COOL...DRY AIR MASS REMAINS ALOFT. NORTHERLY
WINDS CONTINUE TO BE BREEZY WITH GUSTS OF 40 TO 50 MPH IN THE MOST
EXPOSED LOCATIONS IN THE HIGHER ELEVATIONS ACROSS THE NORTH BAY
AND EAST BAY. THIS HAS RESULTED IN A GOOD AMOUNT OF MIXING AND
TEMPERATURES GENERALLY REMAIN IN THE 50S IN MOST VALLEY LOCATIONS
ACROSS THE NORTH. EXPECTING THESE WIND SPEEDS TO PERSIST THROUGH
THE MORNING HOURS AND WILL KEEP THE WIND ADVISORY IN EFFECT UNTIL
10 AM PST. AS THE PRESSURE GRADIENT RELAXES...WIND SPEEDS WILL
DIMINISH SOME BY THIS AFTERNOON.
THE MID/UPPER LEVEL SYSTEM THAT BROUGHT SCATTERED SHOWERS AND A
FEW THUNDERSTORMS TO THE REGION YESTERDAY CONTINUES TO BE
POSITIONED OVER CENTRAL CALIFORNIA AND NEVADA AT THIS HOUR.
LINGERING MOISTURE COMBINED WITH MID/UPPER LEVEL SUPPORT WILL
RESULT IN ISOLATED SHOWERS AND THUNDERSTORMS AGAIN OVER MONTEREY
AND SAN BENITO COUNTIES THIS AFTERNOON. HOWEVER...SHOWER ACTIVITY
IS EXPECTED TO BE LESS WIDESPREAD TODAY WITH DRIER AIR WRAPPING
AROUND THE WESTERN PERIPHERY OF THE UPPER LOW. RAIN CHANCES WILL
COME TO AN END BY LATE THIS EVENING AS THE UPPER LEVEL FEATURE
EJECTS TOWARD THE DESERT SOUTHWEST ON TUESDAY. MEANWHILE...THE
UPPER LEVEL RIDGE OFF OF THE WEST COAST WILL RESULT IN DRY
WEATHER CONDITIONS AND A SLIGHT WARMING TREND THROUGH AT LEAST
THURSDAY NIGHT.
THE FORECAST MODELS CONTINUE TO DEPICT A MID/UPPER LEVEL TROUGH
DROPPING OUT OF THE GULF OF ALASKA LATE THIS WEEK THAT WILL THEN
SLIDE DOWN THE WEST COAST THIS WEEKEND. AS A RESULT...WILL
MAINTAIN PRECIPITATION CHANCES OVER THE NORTH BAY ON FRIDAY AND
ACROSS MUCH OF THE REGION INTO SATURDAY NIGHT. WHILE CONFIDENCE
HAS INCREASED SLIGHTLY FOR SOME SORT OF A PATTERN CHANGE...THERE
REMAINS INCONSISTENCY AMONG THE MEDIUM RANGE MODELS LATE IN THE
FORECAST PERIOD.
&&
.AVIATION...AS OF 4:12 AM PST MONDAY...IT`S MUCH DRIER AROUND THE
AREA. DEWPOINT TEMPS AND HUMIDITY HAVE TUMBLED DOWNWARD AS
DOWNSLOPING WINDS OFF THE SIERRA NEVADA AND COASTAL MTNS CONTINUE
TO SUPPORT DRY WEATHER /VFR CONDITIONS/ FOR THE PERIOD. AREAS OF
GUSTY N-NE WINDS ARE PERSISTING THIS MORNING WITH THE HIGHER GUSTS
IN THE EAST AND NORTH BAY MTNS AND HILLS. SURFACE WINDS AT THE KOAK
TERMINAL HAVE BEEN LOWERING ENOUGH TO CONSIDER INCLUDING NON-CONVECTIVE
LOW LEVEL WIND SHEAR IN THE TAF BUT WILL WAIT ON THIS AS THE SURFACE
WINDS HAVE RECENTLY PICKED BACK UP AGAIN. THE NORTHERLY GRADIENT
UKI-STS IS STRONG AT 2.5 MB. THE WMC-SFO AND ACV-SFO GRADIENTS ARE
9.1 MB AND 5.3 MB RESPECTIVELY AND THE NAM MODEL FORECASTS THEM TO
STRENGTHEN MORE TODAY THEN TAPER OFF SLOWLY BEGINNING VERY LATE
TONIGHT AND TUESDAY. EPAC UPPER LEVEL RIDGING WILL SLOWLY EDGE
EASTWARD BACK OVER CA THROUGH MID-WEEK.
VICINITY OF KSFO...VFR.
KSFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY AREA TERMINALS...VFR.
&&
.MARINE...AS OF 3:59 AM PST MONDAY...HIGH PRESSURE WILL CONTINUE
OVER THE GREAT BASIN AND NORTHERNMOST CALIFORNIA TODAY AND
TONIGHT. THIS WILL RESULT IN A LIGHT TO MODERATE NORTHERLY WIND.
WINDS WILL BECOME NORTHWESTERLY OVER THE COASTAL WATERS BY ON
TUESDAY. A LOW PRESSURE AREA OVER THE GULF OF ALASKA WILL MOVE TO
THE BAY AREA FRIDAY BRINGING WITH IT A CHANCE OF SHOWERS.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...WIND ADVISORY...NORTH AND EAST BAY HILLS UNTIL 10 AM
SCA...SF BAY NORTH OF THE BAY BRIDGE UNTIL 3 PM
&&
$$
PUBLIC FORECAST: BELL/RGASS
AVIATION/MARINE: CANEPA
VISIT US AT WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSBAYAREA
WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS PUEBLO CO
315 PM MST MON FEB 23 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 314 PM MST MON FEB 23 2015
AN UPR LOW OVR CA TODAY IS EXPECTED TO MOVE EASTWARD TONIGHT...
MOVING INTO NORTH CENTRAL AZ BY 12Z TUE...AND THEN WEAKENING AND
MOVING SOUTHEASTWARD THRU NM ON TUE.
SNOW HAS CONTINUED FALLING OVER THE MTNS AND HIGH VALLEYS THIS
AFTERNOON. IN THE SAN LUIS VALLEY THE SNOW HAS NOT BEEN WIDESPREAD
AND IT FAIRLY SPOTTY AND WL CANCEL SNOW ADVISORY AT 3 PM.
OVER THE SANGRE DE CRISTO MTNS THE SNOW IS ALSO BECOMING MORE
SPOTTY...EXCEPT OVR THE FAR SRN AREAS NR THE NEW MEXICO BORDER. WL
ALLOW THAT ADVISORY TO EXPIRE AT 3 PM.
THE NAM AND HRRR SHOW PCPN CHANCE DECREASING RAPIDLY IN THE EVENING
HOURS OVR MOST OF THE MTNS AND HIGH VALLEY AREAS. THE NAM KEEPS
WIDESPREAD SNOW OVR THE ERN SAN JUANS EARLY IN THE EVENING. WEB CAMS
SHOULD LITTLE IN THE WAY OF SNOWFALL CURRENTLY AT LXV AND MONARCH
PASS...SO WL CANCEL THE WARNINGS FOR LAKE AND CHAFFEE COUNTIES AT 3
PM...ALONG WITH CANCELING WARNINGS FOR ZONES 64 AND 65...BUT WL
LEAVE WARNINGS IN EFFECT UNTIL 5 PM FOR ZONES 66 AND 67. WL LEAVE
THE WARNING FOR THE ERN SAN JUANS (ZONE 68) IN EFFECT UNTIL 06Z.
ERN SAN JUANS COULD GET ANOTHER FEW INCHES IN THE EVENING
HOURS...WITH LITTLE ADDITIONAL ACCUMULATION AFTER MIDNIGHT AS THE
SNOW TAPERS OFF.
BY 09Z THE NAM SHOWS DRY WX OVR THE ENTIRE FORECAST AREA...WITH DRY
CONDITIONS THRU AT LEAST MIDMORNING TUE. THE NAM THEN SHOWS THE
POTENTIAL FOR SOME LIGHT PCPN AGAIN OVR THE SW MTNS AS THE UPR LOW
MOVES INTO NM. HOWEVER THE GFS HAS LIGHT PCPN CONTINUING OVR THE SW
MTNS AND THE SANGRES THRU THE NIGHT AND THRU TUE. THE ECMWF IS
SIMILAR TO THE GFS BUT DOES NOT SPREAD THE PCPN ON TUE QUITE AS FAR
NORTH. HAVE DECIDED TO KEEP LOW POPS OVR THE SANGRES AND PORTIONS
OF THE CENTRAL MTNS THRU TONIGHT AND TUE...WITH HIGHER POPS OVR THE
SW MTNS DURING THIS SAME TIME-FRAME...BUT NOT EXPECTING ANYTHING
MORE THAN SOME LIGHT ACCUMULATIONS.
IT IS POSSIBLE FOR THE SAN LUIS VALLEY TO SEE SOME VERY LIGHT SNOW
DEVELOP AGAIN AS LOW CLOUDS COVER MUCH OF THE AREA.
TEMPS WL BE WARMER ON TUE...BUT THE SNOW COVER IN MANY LOCATIONS WL
LIMIT THE AMOUNT OF WARMING AND SO WL STAY BELOW GUIDANCE IN MANY
AREAS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 314 PM MST MON FEB 23 2015
...ACTIVE AND COLD WEATHER PATTERN TO CONTINUE...
MODELS IN GOOD AGREEMENT WITH ACTIVE WEATHER PERSISTING THROUGH
THE EXTENDED PERIOD. SEVERAL DISTURBANCES WILL KEEP PERIODS OF
MODERATE TO HEAVY SNOW GOING FOR MOST OF SOUTHERN COLORADO.
TUESDAY NIGHT...AN UPPER LEVEL DISTURBANCE WILL BE EXITING THE
DESERT SOUTHWEST INTO TEXAS EARLY TUESDAY NIGHT. LIGHT LINGERING
SNOWFALL OVER THE SOUTHERN SAN JUANS SHOULD COME TO AN END BY
MIDNIGHT. A SECONDARY DISTURBANCE WILL BE DROPPING SOUTH OUT OF
THE NORTHERN ROCKIES LATE TUESDAY NIGHT WITH LIGHT SNOW DEVELOPING
OVER THE CENTRAL MOUNTAINS BY WEDNESDAY MORNING.
WEDNESDAY AND THURSDAY...THE SHORTWAVE OVER THE NORTHERN ROCKIES
IS FORECAST TO STRENGTHEN AND DROP SOUTH ACROSS COLORADO THROUGH
THIS PERIOD. THERE ARE A FEW SLIGHT MODEL DIFFERENCES WHICH COULD
PLAY A ROLE IN HOW MUCH SNOW SOME AREAS SEE. SNOW WILL BE ON THE
INCREASE OVER THE CENTRAL MOUNTAINS WEDNESDAY MORNING AND SPREAD
SOUTH AND EAST INTO THE PALMER DIVIDE BY WEDNESDAY AFTERNOON.
ACROSS THE PLAINS...A STRONG COLD FRONT IS FORECAST TO DROP SOUTH
BY LATE WEDNESDAY AFTERNOON. FLOW BEHIND THE COLD FRONT IS
FORECAST TO TRANSITION NORTHEASTERLY HELPING TO PRODUCE LOW LEVEL
UPSLOPE FLOW AS THE UPPER DISTURBANCE DROPS ACROSS THE AREA.
HEAVY SNOW IS LIKELY TO DEVELOP OVER THE EASTERN MOUNTAINS...DOWN
INTO THE I-25 CORRIDOR WEDNESDAY EVENING AND CONTINUE INTO
THURSDAY MORNING. SNOW TOTALS LOOK TO BE HIGHEST OVER THE CENTRAL
MOUNTAINS WHERE ANOTHER FOOT OR MORE OF SNOW IS EXPECTED...WHILE
THE LOWER ELEVATIONS ALONG THE I-25 CORRIDOR WILL SEE 2 TO 6
INCHES. LIGHT SNOW IS EXPECTED ACROSS ALL THE EASTERN PLAINS WITH
1 TO 3 INCHES POSSIBLE. THE MAIN MODEL DIFFERENCE IS WITH THE NAM
WHICH KEEPS LOW AND MID LEVEL FLOW A BIT MORE NORTHERLY...WHICH
WOULD LIMIT UPSLOPE EFFECTS AND SNOW TOTALS ALONG THE I-25
CORRIDOR. THIS WILL NEED TO BE MONITORED. THE HEAVIEST SNOW WILL
COME TO AN END BY LATE THURSDAY MORNING...WITH LIGHT SNOW LIKELY
LINGERING ACROSS THE AREA THROUGH THURSDAY NIGHT. TEMPERATURES
WILL BE COLD WITH 30S FOR HIGHS ON WEDNESDAY...WITH 20S ON
THURSDAY.
FRIDAY...BROAD NORTHWEST FLOW WILL TRANSITION TO SOUTHWESTERLY
FLOW AS THE NEXT UPPER LEVEL DISTURBANCE DROPS SOUTH ALONG THE
WEST COAST. WEAK ENERGY MOVING ACROSS THE REGION WILL LIKELY KEEP
LIGHT SNOW GOING OVER THE MOUNTAINS. TEMPERATURES WILL REMAIN COLD
ACROSS THE PLAINS WITH 20S FOR HIGHS.
SATURDAY THROUGH MONDAY...THE UPPER SYSTEM ALONG THE WEST COAST IS
FORECAST TO STRENGTHEN AND SLOWLY DRIFT SOUTH INTO SOUTHERN
CALIFORNIA BY EARLY NEXT WEEK. SOUTHWESTERLY FLOW WILL TAP INTO
SUBTROPICAL MOISTURE AND SPREAD IT NORTHEASTWARD ACROSS COLORADO.
THIS WILL SET THE STAGE FOR HEAVY SNOWFALL ALONG THE CONTINENTAL
DIVIDE THROUGH THE WEEKEND...WITH THE HEAVIEST SNOWFALL OVER THE
SAN JUAN RANGE. MODELS KEEP LIGHT SNOW ACROSS ALL OF SOUTHERN
COLORADO THROUGH THE WEEKEND. COLD AIR WILL REMAIN IN PLACE WITH
30S FOR HIGHS ACROSS THE LOWER ELEVATIONS. MOZLEY
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 314 PM MST MON FEB 23 2015
KPUB IS EXPECTED TO HAVE VFR CONDITIONS TONIGHT AND TUESDAY. KALS
SHOULD SEE VFR CONDITIONS IN THE EVENING HOURS UNLESS SOME SHOWERS
ARE IN THE VCNTY WHICH COULD LEAD TO BRIEF MVFR CONDITIONS. THEN
LATE TONIGHT KALS SHOULD SEE LOW CLOUDS AND FOG DEVELOP WITH IFR OR
LIFR CONDITIONS INTO MIDMORNING TUE...AND THEN VFR CONDITIONS FOR
THE LATE MORNING AND AFTERNOON. KCOS MAY STILL HAVE SOME VERY LIGHT
SNOW IN THE VCNTY IN THE EARLY EVENING HOURS WITH MVFR OR IFR
CONDITIONS...THEN BY LATE EVENING CONDITIONS ARE EXPECTED TO BECOME
VFR AS SFC WINDS BECOME NW TO N.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 11 PM MST THIS EVENING FOR COZ068.
WINTER STORM WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ066-
067.
&&
$$
SHORT TERM...28
LONG TERM...MOZLEY
AVIATION...28
AREA FORECAST DISCUSSION
NWS PUEBLO CO
304 PM MST MON FEB 23 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 303 PM MST MON FEB 23 2015
AN UPR LOW OVR CA TODAY IS EXPECTED TO MOVE EASTWARD TONIGHT...
MOVING INTO NORTH CENTRAL AZ BY 12Z TUE...AND THEN WEAKENING AND
MOVING SOUTHEASTWARD THRU NM ON TUE.
SNOW HAS CONTINUED FALLING OVER THE MTNS AND HIGH VALLEYS THIS
AFTERNOON. IN THE SAN LUIS VALLEY THE SNOW HAS NOT BEEN WIDESPREAD
AND IT FAIRLY SPOTTY AND WL CANCEL SNOW ADVISORY AT 3 PM.
OVER THE SANGRE DE CRISTO MTNS THE SNOW IS ALSO BECOMING MORE
SPOTTY...EXCEPT OVR THE FAR SRN AREAS NR THE NEW MEXICO BORDER. WL
ALLOW THAT ADVISORY TO EXPIRE AT 3 PM.
THE NAM AND HRRR SHOW PCPN CHANCE DECREASING RAPIDLY IN THE EVENING
HOURS OVR MOST OF THE MTNS AND HIGH VALLEY AREAS. THE NAM KEEPS
WIDESPREAD SNOW OVR THE ERN SAN JUANS EARLY IN THE EVENING. WEB CAMS
SHOULD LITTLE IN THE WAY OF SNOWFALL CURRENTLY AT LXV AND MONARCH
PASS...SO WL CANCEL THE WARNINGS FOR LAKE AND CHAFFEE COUNTIES AT 3
PM...ALONG WITH CANCELING WARNINGS FOR ZONES 64 AND 65...BUT WL
LEAVE WARNINGS IN EFFECT UNTIL 5 PM FOR ZONES 66 AND 67. WL LEAVE
THE WARNING FOR THE ERN SAN JUANS (ZONE 68) IN EFFECT UNTIL 06Z.
ERN SAN JUANS COULD GET ANOTHER FEW INCHES IN THE EVENING
HOURS...WITH LITTLE ADDITIONAL ACCUMULATION AFTER MIDNIGHT AS THE
SNOW TAPERS OFF.
BY 09Z THE NAM SHOWS DRY WX OVR THE ENTIRE FORECAST AREA...WITH DRY
CONDITIONS THRU AT LEAST MIDMORNING TUE. THE NAM THEN SHOWS THE
POTENTIAL FOR SOME LIGHT PCPN AGAIN OVR THE SW MTNS AS THE UPR LOW
MOVES INTO NM. HOWEVER THE GFS HAS LIGHT PCPN CONTINUING OVR THE SW
MTNS AND THE SANGRES THRU THE NIGHT AND THRU TUE. THE ECMWF IS
SIMILAR TO THE GFS BUT DOES NOT SPREAD THE PCPN ON TUE QUITE AS FAR
NORTH. HAVE DECIDED TO KEEP LOW POPS OVR THE SANGRES AND PORTIONS
OF THE CENTRAL MTNS THRU TONIGHT AND TUE...WITH HIGHER POPS OVR THE
SW MTNS DURING THIS SAME TIME-FRAME...BUT NOT EXPECTING ANYTHING
MORE THAN SOME LIGHT ACCUMULATIONS.
IT IS POSSIBLE FOR THE SAN LUIS VALLEY TO SEE SOME VERY LIGHT SNOW
DEVELOP AGAIN AS LOW CLOUDS COVER MUCH OF THE AREA.
TEMPS WL BE WARMER ON TUE...BUT THE SNOW COVER IN MANY LOCATIONS WL
LIMIT THE AMOUNT OF WARMING AND SO WL STAY BELOW GUIDANCE IN MANY
AREAS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 303 PM MST MON FEB 23 2015
...ACTIVE AND COLD WEATHER PATTERN TO CONTINUE...
MODELS IN GOOD AGREEMENT WITH ACTIVE WEATHER PERSISTING THROUGH
THE EXTENDED PERIOD. SEVERAL DISTURBANCES WILL KEEP PERIODS OF
MODERATE TO HEAVY SNOW GOING FOR MOST OF SOUTHERN COLORADO.
TUESDAY NIGHT...AN UPPER LEVEL DISTURBANCE WILL BE EXITING THE
DESERT SOUTHWEST INTO TEXAS EARLY TUESDAY NIGHT. LIGHT LINGERING
SNOWFALL OVER THE SOUTHERN SAN JUANS SHOULD COME TO AN END BY
MIDNIGHT. A SECONDARY DISTURBANCE WILL BE DROPPING SOUTH OUT OF
THE NORTHERN ROCKIES LATE TUESDAY NIGHT WITH LIGHT SNOW DEVELOPING
OVER THE CENTRAL MOUNTAINS BY WEDNESDAY MORNING.
WEDNESDAY AND THURSDAY...THE SHORTWAVE OVER THE NORTHERN ROCKIES
IS FORECAST TO STRENGTHEN AND DROP SOUTH ACROSS COLORADO THROUGH
THIS PERIOD. THERE ARE A FEW SLIGHT MODEL DIFFERENCES WHICH COULD
PLAY A ROLE IN HOW MUCH SNOW SOME AREAS SEE. SNOW WILL BE ON THE
INCREASE OVER THE CENTRAL MOUNTAINS WEDNESDAY MORNING AND SPREAD
SOUTH AND EAST INTO THE PALMER DIVIDE BY WEDNESDAY AFTERNOON.
ACROSS THE PLAINS...A STRONG COLD FRONT IS FORECAST TO DROP SOUTH
BY LATE WEDNESDAY AFTERNOON. FLOW BEHIND THE COLD FRONT IS
FORECAST TO TRANSITION NORTHEASTERLY HELPING TO PRODUCE LOW LEVEL
UPSLOPE FLOW AS THE UPPER DISTURBANCE DROPS ACROSS THE AREA.
HEAVY SNOW IS LIKELY TO DEVELOP OVER THE EASTERN MOUNTAINS...DOWN
INTO THE I-25 CORRIDOR WEDNESDAY EVENING AND CONTINUE INTO
THURSDAY MORNING. SNOW TOTALS LOOK TO BE HIGHEST OVER THE CENTRAL
MOUNTAINS WHERE ANOTHER FOOT OR MORE OF SNOW IS EXPECTED...WHILE
THE LOWER ELEVATIONS ALONG THE I-25 CORRIDOR WILL SEE 2 TO 6
INCHES. LIGHT SNOW IS EXPECTED ACROSS ALL THE EASTERN PLAINS WITH
1 TO 3 INCHES POSSIBLE. THE MAIN MODEL DIFFERENCE IS WITH THE NAM
WHICH KEEPS LOW AND MID LEVEL FLOW A BIT MORE NORTHERLY...WHICH
WOULD LIMIT UPSLOPE EFFECTS AND SNOW TOTALS ALONG THE I-25
CORRIDOR. THIS WILL NEED TO BE MONITORED. THE HEAVIEST SNOW WILL
COME TO AN END BY LATE THURSDAY MORNING...WITH LIGHT SNOW LIKELY
LINGERING ACROSS THE AREA THROUGH THURSDAY NIGHT. TEMPERATURES
WILL BE COLD WITH 30S FOR HIGHS ON WEDNESDAY...WITH 20S ON
THURSDAY.
FRIDAY...BROAD NORTHWEST FLOW WILL TRANSITION TO SOUTHWESTERLY
FLOW AS THE NEXT UPPER LEVEL DISTURBANCE DROPS SOUTH ALONG THE
WEST COAST. WEAK ENERGY MOVING ACROSS THE REGION WILL LIKELY KEEP
LIGHT SNOW GOING OVER THE MOUNTAINS. TEMPERATURES WILL REMAIN COLD
ACROSS THE PLAINS WITH 20S FOR HIGHS.
SATURDAY THROUGH MONDAY...THE UPPER SYSTEM ALONG THE WEST COAST IS
FORECAST TO STRENGTHEN AND SLOWLY DRIFT SOUTH INTO SOUTHERN
CALIFORNIA BY EARLY NEXT WEEK. SOUTHWESTERLY FLOW WILL TAP INTO
SUBTROPICAL MOISTURE AND SPREAD IT NORTHEASTWARD ACROSS COLORADO.
THIS WILL SET THE STAGE FOR HEAVY SNOWFALL ALONG THE CONTINENTAL
DIVIDE THROUGH THE WEEKEND...WITH THE HEAVIEST SNOWFALL OVER THE
SAN JUAN RANGE. MODELS KEEP LIGHT SNOW ACROSS ALL OF SOUTHERN
COLORADO THROUGH THE WEEKEND. COLD AIR WILL REMAIN IN PLACE WITH
30S FOR HIGHS ACROSS THE LOWER ELEVATIONS. MOZLEY
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 303 PM MST MON FEB 23 2015
KPUB IS EXPECTED TO HAVE VFR CONDITIONS TONIGHT AND TUESDAY. KALS
SHOULD SEE VFR CONDITIONS IN THE EVENING HOURS UNLESS SOME SHOWERS
ARE IN THE VCNTY WHICH COULD LEAD TO BRIEF MVFR CONDITIONS. THEN
LATE TONIGHT KALS SHOULD SEE LOW CLOUDS AND FOG DEVELOP WITH IFR OR
LIFR CONDITIONS INTO MIDMORNING TUE...AND THEN VFR CONDITIONS FOR
THE LATE MORNING AND AFTERNOON. KCOS MAY STILL HAVE SOME VERY LIGHT
SNOW IN THE VCNTY IN THE EARLY EVENING HOURS WITH MVFR OR IFR
CONDITIONS...THEN BY LATE EVENING CONDITIONS ARE EXPECTED TO BECOME
VFR AS SFC WINDS BECOME NW TO N.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 11 PM MST THIS EVENING FOR COZ068.
WINTER STORM WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ060-
066-067.
&&
$$
SHORT TERM...28
LONG TERM...MOZLEY
AVIATION...28
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1219 PM MST MON FEB 23 2015
.UPDATE...
ISSUED AT 1134 AM MST MON FEB 23 2015
ALLOWED THE WINTER ADVISORY FOR THE GRAND VALLEY AND THE WINTER
STORM WARNINGS FOR THE DEBEQUE-SILT CORRIDOR AND CENTRAL CO RIVER
VALLEY TO EXPIRE AT NOON. LIGHT SNOW WILL HANG AROUND IN PLACES
ALONG THE I-70 CORRIDOR THIS AFTERNOON BUT AMOUNTS ARE EXPECTED TO
BE AN INCH OR LESS. TEMPS NEAR OR BELOW FREEZING COULD ALSO KEEP
UNTREATED ROADS/SIDEWALKS SLICK. ALSO LET THE WINTER STORM WARNINGS
EXPIRE FOR THE ROAN/TAVAPUTS PLATEAU AND THE FLAT TOPS/WHITE RIVER
PLATEAU AS OVERALL FORCING SLOWLY SHIFTS SOUTHWARD.
SNOW SHOULD REMAIN WIDESPREAD ACROSS SE UT AND SW CO THROUGH THE
AFTERNOON...BUT MODELS INDICATING A LULL IN THE ACTIVITY OR JUST
SOME LIGHT SNOW THIS EVENING. ANOTHER BURST OF A COUPLE INCHES OF
SNOW THEN EXPECTED TOWARD SUNRISE FOR FAR SE UT AND SW CO AS THE
MAIN UPPER LOW CURRENTLY OVER CENTRAL CA MOVES ACROSS NRN AZ.
UPDATE ISSUED AT 1013 AM MST MON FEB 23 2015
SNOW REMAINED WIDESPREAD ACROSS SW CO THIS MORNING...PRETTY MUCH
FROM GRAND JCT AND ASPEN SOUTH. OBSERVATIONS INDICATING THE HEAVIER
SNOW FROM ABOUT MONTROSE/PARADOX VALLEY SOUTH. SNOW ALSO NOTED
ACROSS MUCH OF SE UT. THIS UNDER A BROAD AREA OF UPPER DIVERGENCE/
LOWER (MOISTURE)CONVERGENCE PLUS ISENTROPIC UPGLIDE AND A MOIST
DENDRITIC SNOW GROWTH ZONE. EARLY LOOK AT THIS MORNING`S MODELS SHOW
THE HEAVIER SNOW BAND SLOWLY SHIFTNIG SOUTH WITH SOME REDUCTION IN
UPPER LEVEL SUPPORT AS THE UPPER JET ACROSS NRN AZ AND NRN NM
PROGRESSES EASTWARD. WINTER STORM WARNINGS CONTINUE FOR SE UT AND
SW CO. STILL ASSESSING WHETHER OR NOT TO EXTEND THE HIGHLIGHTS
INTO TUE FOR AT LEAST THE AREAS FROM THE ABAJOS AND SAN JUANS
SOUTH.
LIGHT SNOW IN THE GRAND VALLEY THIS MORNING BELIEVED TO BE MAINLY
DUE TO MOISTURE IN SSW FLOW OVERRUNNING COLD AIR TRAPPED IN THE
VALLEY. NAM12 AND HIGH RESOLUTION RAP MODELS SUGGEST THIS MOIST
OVERRUNNING DECREASES FOR THE GRAND VALLEY THIS AFTERNOON AS FLOW
ALOFT BEGINS TO TAKE ON A MORE NORTHERLY TACK. THESE MODELS ALSO
SHOW ONLY LIGHT SNOW ACCUMS THERE THIS AFTERNOON. WHETHER TO EXTEND
THE ADVISORY FOR THE GRAND INTO THIS AFTERNOON WILL PROBABLY BE A
LAST- MINUTE CALL AND SOMEWHAT DEPENDENT ON HOW MUCH TEMPS WARM TO
EASE THE THREAT OF ICY ROADS AND SIDEWALKS. BELIEVE THE NOONTIME
EXPIRATION OF THE WINTER HIGHLIGHT FOR THE DEBEQUE TO SILT
CORRIDOR AND THE CENTRAL CO RIVER VALLEY STILL LOOKS ON TRACK.
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 519 AM MST MON FEB 23 2015
SNOWFALL CONTINUES ACROSS MOST OF THE SOUTHERN HALF OF THE
FORECAST AREA...AND NORTHWARD ACROSS THE I-70 CORRIDOR EARLY THIS
MORNING. ALREADY SIGNIFICANT AMOUNTS HAVE FALLEN FROM THE
UNCOMPAHGRE RIVER BASIN SOUTH TO THE NM BORDER...WITH MORE
EXPECTED THROUGH TODAY. SNOW IN THE CENTRAL VALLEYS FROM MOAB TO
GRAND JUNCTION TO EAGLE HAS BEEN MORE ON THE LIGHT SIDE. WILL DROP
THE ADVISORY FOR MOAB AND THE GRAND FLAT WITH THIS PACKAGE AS THAT
ZONE HAS RECEIVED VERY LITTLE SNOW...WITH NOT MUCH MORE EXPECTED.
HOWEVER WILL KEEP THE HIGHLIGHTS GOING FOR THE COLORADO I-70
CORRIDOR AS THOSE ZONES HAVE RECEIVED ENOUGH TO AFFECT
TRAVEL...AND MODEST AMOUNTS ARE STILL EXPECTED THROUGH THE
MORNING. HAVE ALSO OPTED TO END THE WARNINGS EARLY FOR THE
COLORADO TAVAPUTS AND THE FLATTOPS...TO COINCIDE WITH THE END
TIMING OF THESE I-70 CORRIDOR VALLEY ZONES WHICH EXPIRE AT NOON.
ON THE FLIP SIDE HAVE EXTENDED THE WARNING FOR UT ZONE 29 UNTIL
MIDNIGHT TO MATCH UP BETTER WITH THE HIGHLIGHTS FOR OTHER
SOUTHEAST UT AND SOUTHWEST CO ZONES. ALL OF SOUTHEAST UT AND
SOUTHWEST CO FROM AROUND THE LA SAL MOUNTAINS EAST TO THE
SOUTHERN SLOPES OF THE GRAND MESA AND THE WEST ELKS...AND
SOUTHWARD TO THE NM/AZ BORDERS WILL CONTINUE TO BE UNDER THE GUN
TODAY AS A MOIST AND UNSTABLE AIR MASS CONTINUES TO FLOW INTO THE
REGION. A CONVERGENT ZONE HAS DEVELOPED FROM AROUND BLANDING TO
MONTROSE AND WILL PERSIST MORE OR LESS THROUGH THE DAY. THIS IS
ALL THE RESULT OF A LOW PRESSURE CENTER THAT WILL CLOSE OFF OVER
CENTRAL CALIFORNIA TODAY...THEN MOVE INTO NORTHWEST AZ TONIGHT. AS
A RESULT A DEFORMATION ZONE WILL DEVELOP ACROSS THE SOUTHERN
PORTION OF OUR AREA AND KEEP MODERATE TO HEAVY SNOW INTO THE
EVENING OVER THE SOUTHERN ZONES. ENOUGH COOLING WILL HAVE OCCURRED
BY THIS AFTERNOON...THAT I DO NOT EXPECT SNOW TO CHANGE OVER...OR
EVEN MIX WITH TO RAIN EXCEPT POSSIBLY FOR BRIEF PERIODS IN THE
LOWEST SOUTHERN VALLEYS.
THE LOW WILL THEN MOVE INTO CENTRAL/SOUTHERN NEW MEXICO ON TUE
WITH PRECIPITATION PERSISTING INTO THE AFTERNOON OVER THE SOUTHERN
EDGE. HOWEVER SNOW INTENSITY LATE TONIGHT THROUGH TUE IS MOSTLY
EXPECTED TO BE LIGHT...ESPECIALLY WHEN COMPARED TO THE AMOUNTS
THIS STORM HAS ALREADY PRODUCED.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 519 AM MST MON FEB 23 2015
SNOW FINALLY DIMINISHES ACROSS THE SOUTH AS THE LATEST STORM IS
FORCED TO THE SOUTHEAST TUESDAY NIGHT. HOWEVER...EXPECT SOME
LIGHT SNOW TO BEGIN ACROSS THE NORTHERN COLORADO MOUNTAINS LATER
IN THE NIGHT AS MOISTURE AHEAD OF AN APPROACHING SHORTWAVE TROUGH
TO THE NORTHWEST SWEEPS OVER THE AREA. EXPECT SNOW TO INCREASE AND
SPREAD INTO THE SOUTHERN MOUNTAINS AND ADJACENT VALLEYS WEDNESDAY
AND WEDNESDAY NIGHT AS THE SHORTWAVE TROUGH PASSES SOUTHEASTWARD
ACROSS THE AREA. IN FACT...A SERIES OF WAVES WILL PASS THROUGH THE
AREA DURING THE REMAINDER OF THE WEEK...MAINLY IMPACTING THE
COLORADO DIVIDE MOUNTAINS. A BIT DIFFICULT TO TIME THESE
DISTURBANCES THIS FAR OUT BUT GOES WITHOUT SAYING THAT THE PATTERN
HAS SHIFTED TO A MORE PROGRESSIVE...WETTER...AND COOLER REGIME.
IN FACT...FOR THOSE ALREADY DIGGING OUT ACROSS SOUTHEAST UTAH AND
SOUTHWEST COLORADO...MODELS ARE HINTING AT THE POTENTIAL FOR ANOTHER
SIGNIFICANT SNOW EVENT THIS WEEKEND. DETAILS A BIT SKETCHY AT THIS
POINT AS GFS AND EC NOT ENTIRELY ON THE SAME PAGE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 519 AM MST MON FEB 23 2015
SNOWFALL CONTINUES ACROSS MOST OF THE SOUTHERN HALF OF THE
FORECAST AREA...AND NORTHWARD ACROSS THE I-70 CORRIDOR EARLY THIS
MORNING. ALREADY SIGNIFICANT AMOUNTS HAVE FALLEN FROM THE
UNCOMPAHGRE RIVER BASIN SOUTH TO THE NM BORDER...WITH MORE
EXPECTED THROUGH TODAY. SNOW IN THE CENTRAL VALLEYS FROM MOAB TO
GRAND JUNCTION TO EAGLE HAS BEEN MORE ON THE LIGHT SIDE. WILL DROP
THE ADVISORY FOR MOAB AND THE GRAND FLAT WITH THIS PACKAGE AS THAT
ZONE HAS RECEIVED VERY LITTLE SNOW...WITH NOT MUCH MORE EXPECTED.
HOWEVER WILL KEEP THE HIGHLIGHTS GOING FOR THE COLORADO I-70
CORRIDOR AS THOSE ZONES HAVE RECEIVED ENOUGH TO AFFECT
TRAVEL...AND MODEST AMOUNTS ARE STILL EXPECTED THROUGH THE
MORNING. HAVE ALSO OPTED TO END THE WARNINGS EARLY FOR THE
COLORADO TAVAPUTS AND THE FLATTOPS...TO COINCIDE WITH THE END
TIMING OF THESE I-70 CORRIDOR VALLEY ZONES WHICH EXPIRE AT NOON.
ON THE FLIP SIDE HAVE EXTENDED THE WARNING FOR UT ZONE 29 UNTIL
MIDNIGHT TO MATCH UP BETTER WITH THE HIGHLIGHTS FOR OTHER
SOUTHEAST UT AND SOUTHWEST CO ZONES. ALL OF SOUTHEAST UT AND
SOUTHWEST CO FROM AROUND THE LA SAL MOUNTAINS EAST TO THE
SOUTHERN SLOPES OF THE GRAND MESA AND THE WEST ELKS...AND
SOUTHWARD TO THE NM/AZ BORDERS WILL CONTINUE TO BE UNDER THE GUN
TODAY AS A MOIST AND UNSTABLE AIR MASS CONTINUES TO FLOW INTO THE
REGION. A CONVERGENT ZONE HAS DEVELOPED FROM AROUND BLANDING TO
MONTROSE AND WILL PERSIST MORE OR LESS THROUGH THE DAY. THIS IS
ALL THE RESULT OF A LOW PRESSURE CENTER THAT WILL CLOSE OFF OVER
CENTRAL CALIFORNIA TODAY...THEN MOVE INTO NORTHWEST AZ TONIGHT. AS
A RESULT A DEFORMATION ZONE WILL DEVELOP ACROSS THE SOUTHERN
PORTION OF OUR AREA AND KEEP MODERATE TO HEAVY SNOW INTO THE
EVENING OVER THE SOUTHERN ZONES. ENOUGH COOLING WILL HAVE OCCURRED
BY THIS AFTERNOON...THAT I DO NOT EXPECT SNOW TO CHANGE OVER...OR
EVEN MIX WITH TO RAIN EXCEPT POSSIBLY FOR BRIEF PERIODS IN THE
LOWEST SOUTHERN VALLEYS.
THE LOW WILL THEN MOVE INTO CENTRAL/SOUTHERN NEW MEXICO ON TUE
WITH PRECIPITATION PERSISTING INTO THE AFTERNOON OVER THE SOUTHERN
EDGE. HOWEVER SNOW INTENSITY LATE TONIGHT THROUGH TUE IS MOSTLY
EXPECTED TO BE LIGHT...ESPECIALLY WHEN COMPARED TO THE AMOUNTS
THIS STORM HAS ALREADY PRODUCED.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 519 AM MST MON FEB 23 2015
SNOW FINALLY DIMINISHES ACROSS THE SOUTH AS THE LATEST STORM IS
FORCED TO THE SOUTHEAST TUESDAY NIGHT. HOWEVER...EXPECT SOME
LIGHT SNOW TO BEGIN ACROSS THE NORTHERN COLORADO MOUNTAINS LATER
IN THE NIGHT AS MOISTURE AHEAD OF AN APPROACHING SHORTWAVE TROUGH
TO THE NORTHWEST SWEEPS OVER THE AREA. EXPECT SNOW TO INCREASE AND
SPREAD INTO THE SOUTHERN MOUNTAINS AND ADJACENT VALLEYS WEDNESDAY
AND WEDNESDAY NIGHT AS THE SHORTWAVE TROUGH PASSES SOUTHEASTWARD
ACROSS THE AREA. IN FACT...A SERIES OF WAVES WILL PASS THROUGH THE
AREA DURING THE REMAINDER OF THE WEEK...MAINLY IMPACTING THE
COLORADO DIVIDE MOUNTAINS. A BIT DIFFICULT TO TIME THESE
DISTURBANCES THIS FAR OUT BUT GOES WITHOUT SAYING THAT THE PATTERN
HAS SHIFTED TO A MORE PROGRESSIVE...WETTER...AND COOLER REGIME.
IN FACT...FOR THOSE ALREADY DIGGING OUT ACROSS SOUTHEAST UTAH AND
SOUTHWEST COLORADO...MODELS ARE HINTING AT THE POTENTIAL FOR ANOTHER
SIGNIFICANT SNOW EVENT THIS WEEKEND. DETAILS A BIT SKETCHY AT THIS
POINT AS GFS AND EC NOT ENTIRELY ON THE SAME PAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1013 AM MST MON FEB 23 2015
THIS WINTER STORM IS SLOWLY WINDING DOWN BUT PLENTY OF AVIATION
CONCERNS WILL CONTINUE OVER THE NEXT 24 HOURS. SNOW LOOKS TO
CONTINUE ACROSS SOUTHWEST COLORADO TO SOUTHEAST UTAH...WITH
MVFR/IFR IMPACTS TO THE SOUTHERN FORECAST TERMINALS A HIGH
PROBABILITY TO CONTINUE THROUGH TUESDAY. IMPROVEMENT ALONG THE
WESTERN INTERSTATE 70 CORRIDOR SHOULD OCCUR AFTER 20Z WITH IFR
CONDITIONS HANGING IN AT CNY AND GJT LATE THIS MORNING AND VFR IN
THE COLORADO AND EAGLE VALLEYS TO THE EAST. OBSCURATION OF THE
TERRAIN WILL PERSIST OVER THE NEXT 24 HOURS AS WELL.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ009>012-
014-017>023.
UT...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR UTZ022-029.
WINTER STORM WARNING UNTIL 6 AM MST TUESDAY FOR UTZ028.
&&
$$
UPDATE...JAD
SHORT TERM...EH
LONG TERM...NL
AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1015 AM MST MON FEB 23 2015
.UPDATE...
ISSUED AT 1013 AM MST MON FEB 23 2015
SNOW REMAINED WIDESPREAD ACROSS SW CO THIS MORNING...PRETTY MUCH
FROM GRAND JCT AND ASPEN SOUTH. OBSERVATIONS INDICATING THE HEAVIER
SNOW FROM ABOUT MONTROSE/PARADOX VALLEY SOUTH. SNOW ALSO NOTED
ACROSS MUCH OF SE UT. THIS UNDER A BROAD AREA OF UPPER DIVERGENCE/
LOWER (MOISTURE)CONVERGENCE PLUS ISENTROPIC UPGLIDE AND A MOIST
DENDRITIC SNOW GROWTH ZONE. EARLY LOOK AT THIS MORNING`S MODELS SHOW
THE HEAVIER SNOW BAND SLOWLY SHIFTNIG SOUTH WITH SOME REDUCTION IN
UPPER LEVEL SUPPORT AS THE UPPER JET ACROSS NRN AZ AND NRN NM
PROGRESSES EASTWARD. WINTER STORM WARNINGS CONTINUE FOR SE UT AND
SW CO. STILL ASSESSING WHETHER OR NOT TO EXTEND THE HIGHLIGHTS
INTO TUE FOR AT LEAST THE AREAS FROM THE ABAJOS AND SAN JUANS
SOUTH.
LIGHT SNOW IN THE GRAND VALLEY THIS MORNING BELIEVED TO BE MAINLY
DUE TO MOISTURE IN SSW FLOW OVERRUNNING COLD AIR TRAPPED IN THE
VALLEY. NAM12 AND HIGH RESOLUTION RAP MODELS SUGGEST THIS MOIST
OVERRUNNING DECREASES FOR THE GRAND VALLEY THIS AFTERNOON AS FLOW
ALOFT BEGINS TO TAKE ON A MORE NORTHERLY TACK. THESE MODELS ALSO
SHOW ONLY LIGHT SNOW ACCUMS THERE THIS AFTERNOON. WHETHER TO EXTEND
THE ADVISORY FOR THE GRAND INTO THIS AFTERNOON WILL PROBABLY BE A
LAST- MINUTE CALL AND SOMEWHAT DEPENDENT ON HOW MUCH TEMPS WARM TO
EASE THE THREAT OF ICY ROADS AND SIDEWALKS. BELIEVE THE NOONTIME
EXPIRATION OF THE WINTER HIGHLIGHT FOR THE DEBEQUE TO SILT
CORRIDOR AND THE CENTRAL CO RIVER VALLEY STILL LOOKS ON TRACK.
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 519 AM MST MON FEB 23 2015
SNOWFALL CONTINUES ACROSS MOST OF THE SOUTHERN HALF OF THE
FORECAST AREA...AND NORTHWARD ACROSS THE I-70 CORRIDOR EARLY THIS
MORNING. ALREADY SIGNIFICANT AMOUNTS HAVE FALLEN FROM THE
UNCOMPAHGRE RIVER BASIN SOUTH TO THE NM BORDER...WITH MORE
EXPECTED THROUGH TODAY. SNOW IN THE CENTRAL VALLEYS FROM MOAB TO
GRAND JUNCTION TO EAGLE HAS BEEN MORE ON THE LIGHT SIDE. WILL DROP
THE ADVISORY FOR MOAB AND THE GRAND FLAT WITH THIS PACKAGE AS THAT
ZONE HAS RECEIVED VERY LITTLE SNOW...WITH NOT MUCH MORE EXPECTED.
HOWEVER WILL KEEP THE HIGHLIGHTS GOING FOR THE COLORADO I-70
CORRIDOR AS THOSE ZONES HAVE RECEIVED ENOUGH TO AFFECT
TRAVEL...AND MODEST AMOUNTS ARE STILL EXPECTED THROUGH THE
MORNING. HAVE ALSO OPTED TO END THE WARNINGS EARLY FOR THE
COLORADO TAVAPUTS AND THE FLATTOPS...TO COINCIDE WITH THE END
TIMING OF THESE I-70 CORRIDOR VALLEY ZONES WHICH EXPIRE AT NOON.
ON THE FLIP SIDE HAVE EXTENDED THE WARNING FOR UT ZONE 29 UNTIL
MIDNIGHT TO MATCH UP BETTER WITH THE HIGHLIGHTS FOR OTHER
SOUTHEAST UT AND SOUTHWEST CO ZONES. ALL OF SOUTHEAST UT AND
SOUTHWEST CO FROM AROUND THE LA SAL MOUNTAINS EAST TO THE
SOUTHERN SLOPES OF THE GRAND MESA AND THE WEST ELKS...AND
SOUTHWARD TO THE NM/AZ BORDERS WILL CONTINUE TO BE UNDER THE GUN
TODAY AS A MOIST AND UNSTABLE AIR MASS CONTINUES TO FLOW INTO THE
REGION. A CONVERGENT ZONE HAS DEVELOPED FROM AROUND BLANDING TO
MONTROSE AND WILL PERSIST MORE OR LESS THROUGH THE DAY. THIS IS
ALL THE RESULT OF A LOW PRESSURE CENTER THAT WILL CLOSE OFF OVER
CENTRAL CALIFORNIA TODAY...THEN MOVE INTO NORTHWEST AZ TONIGHT. AS
A RESULT A DEFORMATION ZONE WILL DEVELOP ACROSS THE SOUTHERN
PORTION OF OUR AREA AND KEEP MODERATE TO HEAVY SNOW INTO THE
EVENING OVER THE SOUTHERN ZONES. ENOUGH COOLING WILL HAVE OCCURRED
BY THIS AFTERNOON...THAT I DO NOT EXPECT SNOW TO CHANGE OVER...OR
EVEN MIX WITH TO RAIN EXCEPT POSSIBLY FOR BRIEF PERIODS IN THE
LOWEST SOUTHERN VALLEYS.
THE LOW WILL THEN MOVE INTO CENTRAL/SOUTHERN NEW MEXICO ON TUE
WITH PRECIPITATION PERSISTING INTO THE AFTERNOON OVER THE SOUTHERN
EDGE. HOWEVER SNOW INTENSITY LATE TONIGHT THROUGH TUE IS MOSTLY
EXPECTED TO BE LIGHT...ESPECIALLY WHEN COMPARED TO THE AMOUNTS
THIS STORM HAS ALREADY PRODUCED.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 519 AM MST MON FEB 23 2015
SNOW FINALLY DIMINISHES ACROSS THE SOUTH AS THE LATEST STORM IS
FORCED TO THE SOUTHEAST TUESDAY NIGHT. HOWEVER...EXPECT SOME
LIGHT SNOW TO BEGIN ACROSS THE NORTHERN COLORADO MOUNTAINS LATER
IN THE NIGHT AS MOISTURE AHEAD OF AN APPROACHING SHORTWAVE TROUGH
TO THE NORTHWEST SWEEPS OVER THE AREA. EXPECT SNOW TO INCREASE AND
SPREAD INTO THE SOUTHERN MOUNTAINS AND ADJACENT VALLEYS WEDNESDAY
AND WEDNESDAY NIGHT AS THE SHORTWAVE TROUGH PASSES SOUTHEASTWARD
ACROSS THE AREA. IN FACT...A SERIES OF WAVES WILL PASS THROUGH THE
AREA DURING THE REMAINDER OF THE WEEK...MAINLY IMPACTING THE
COLORADO DIVIDE MOUNTAINS. A BIT DIFFICULT TO TIME THESE
DISTURBANCES THIS FAR OUT BUT GOES WITHOUT SAYING THAT THE PATTERN
HAS SHIFTED TO A MORE PROGRESSIVE...WETTER...AND COOLER REGIME.
IN FACT...FOR THOSE ALREADY DIGGING OUT ACROSS SOUTHEAST UTAH AND
SOUTHWEST COLORADO...MODELS ARE HINTING AT THE POTENTIAL FOR ANOTHER
SIGNIFICANT SNOW EVENT THIS WEEKEND. DETAILS A BIT SKETCHY AT THIS
POINT AS GFS AND EC NOT ENTIRELY ON THE SAME PAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1013 AM MST MON FEB 23 2015
THIS WINTER STORM IS SLOWLY WINDING DOWN BUT PLENTY OF AVIATION
CONCERNS WILL CONTINUE OVER THE NEXT 24 HOURS. SNOW LOOKS TO
CONTINUE ACROSS SOUTHWEST COLORADO TO SOUTHEAST UTAH...WITH
MVFR/IFR IMPACTS TO THE SOUTHERN FORECAST TERMINALS A HIGH
PROBABILITY TO CONTINUE THROUGH TUESDAY. IMPROVEMENT ALONG THE
WESTERN INTERSTATE 70 CORRIDOR SHOULD OCCUR AFTER 20Z WITH IFR
CONDITIONS HANGING IN AT CNY AND GJT LATE THIS MORNING AND VFR IN
THE COLORADO AND EAGLE VALLEYS TO THE EAST. OBSCURATION OF THE
TERRAIN WILL PERSIST OVER THE NEXT 24 HOURS AS WELL.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ009>012-
014-017>023.
WINTER STORM WARNING UNTIL NOON MST TODAY FOR COZ003-007-008-013.
WINTER WEATHER ADVISORY UNTIL NOON MST TODAY FOR COZ006.
UT...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR UTZ022-029.
WINTER STORM WARNING UNTIL 6 AM MST TUESDAY FOR UTZ028.
&&
$$
SHORT TERM...EH
LONG TERM...NL
AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
329 AM MST MON FEB 23 2015
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 329 AM MST MON FEB 23 2015
WK SWLY FLOW ALOFT THIS MORNING WILL BECOME LIGHT NNW BY LATE AFTN
AND CONTINUE TONIGHT. LINGERING MOISTURE EARLY THIS MORNING MAY
ALLOW FOR A FEW AREAS OF VERY LIGHT SNOW IN THE FOOTHILLS AND OVER
PORTIONS OF NERN CO THRU 15Z. IN THE MTNS BEST CHC OF SNOW WILL BE
ALONG AND SOUTH OF I-70 WHICH MAY LINGER THRU THE AFTN HOURS AS
ACTIVITY BECOMES MORE CONVECTIVE DUE TO FAVORABLE LAPSE RATES. AS
FOR HIGHS WILL KEEP READINGS MAINLY IN THE 20-25 RANGE ACROSS NERN
CO.
FOR TONIGHT ANY LINGERING SNOW IN THE MTNS SHOULD END THIS EVENING
WITH DRY CONDITIONS ELSEWHERE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 329 AM MST MON FEB 23 2015
AN ACTIVE AND VERY WINTRY WEATHER PATTERN WILL REMAIN IN PLACE
THROUGH THE UPCOMING WEEK.
TUESDAY IS SHAPING UP TO BE THE MOST QUIET AND WARMEST DAY OF THE
WEEK WITH MOSTLY SUNNY SKIES AND WARM ADVECTION ALOFT.
HOWEVER...ABUNDANT SNOW COVER AND LACK OF DOWNSLOPE WILL LIMIT THE
AMOUNT OF WARMING. WE SHOULD STILL SEE HIGHS APPROACH 40F OVER
SNOW COVERED AREAS OF THE PLAINS...WITH MID/UPPER 40S OVER THE
FAR NORTHEAST CORNER WHERE ONLY A LIGHT DUSTING OF SNOW OCCURRED
WITH THIS LAST STORM.
WEDNESDAY WILL SEE ANOTHER CHANGE. WE SHOULD SEE OROGRAPHIC SNOW
DEVELOP ACROSS THE MOUNTAINS AS EARLY AS LATE TUESDAY NIGHT OR
WEDNESDAY MORNING AS MOISTURE INCREASES AHEAD OF NEXT FAST MOVING
SHORT WAVE. BY LATE MORNING INTO THE AFTERNOON...EXPECT SHOWERS TO
SPILL ACROSS THE PLAINS AND INCREASE IN COVERAGE THROUGH THE
AFTERNOON HOURS BEHIND COLD FRONTAL PASSAGE. SEEMS MODELS ARE A
BIT FASTER WITH THIS COLD FRONT SO SHOULD SEE FALLING TEMPERATURES
AND GUSTY NORTH WINDS ACROSS THE PLAINS THROUGH THE AFTERNOON.
WITH REGARD TO SNOW POTENTIAL...WE DO EXPECT ACCUMULATING
SNOWFALL ACROSS THE MOUNTAINS...FOOTHILLS...AND NEARBY PLAINS
INCLUDING THE I-25 URBAN CORRIDOR WHERE UPSLOPE FLOW WILL ACT TO
FOCUS PRECIPITATION. UPSLOPE IS EXPECTED TO DEEPEN TO 700 MB OR
MORE IN NORTHWEST FLOW ALOFT...AND LAPSE RATES WILL BE NEARLY
NEUTRAL THROUGH A DEEP LAYER DURING THE WEDNESDAY AFTERNOON/EARLY
EVENING HOURS. Q-G FIELDS ALSO SUPPORT DEEP BUT MODEST LIFT DURING
THIS PERIOD. AS A RESULT...CONTINUED TREND OF INCREASING POPS NEAR
THE FRONT RANGE...WITH POTENTIAL FOR A FEW INCHES OF ACCUMULATION.
THE EASTERN PLAINS WILL ALSO SEE A GOOD CHANCE OF SNOW...BUT LACK
OF STRONGER UPSLOPE FORCING WILL LIKELY LIMIT ACCUMULATION
POTENTIAL THERE.
BY THURSDAY...SOME MODELS ARE POINTING AT ANOTHER BUT WEAKER SHORT
WAVE IN NORTHWEST FLOW ALOFT. THIS WILL KEEP A CHANCE OF SOME SNOW
IN THE FORECAST...WHILE COLDER AIR ALSO REMAINS FIRMLY ENTRENCHED
EAST OF THE ROCKIES. HAVE KEPT A COLD FORECAST IN PLACE WITH TEMPS
LIKELY STRUGGLING TO REACH 20F ON THE PLAINS PER LATEST GRIDDED
TEMP OUTPUT.
AT THIS TIME...FRIDAY INTO SATURDAY APPEAR TO BE MAINLY IN
BETWEEN WEATHER SYSTEMS. HOWEVER...HARD TO ELIMINATE SNOW CHANCES
WITH SOME MOISTURE IN NORTHWEST FLOW ALOFT FRIDAY...AND POSSIBLE
FASTER ARRIVAL OF NEXT STORM SYSTEM BY SATURDAY. TEMPERATURES
SHOULD MODERATE DURING THIS TIME FRAME BUT REMAIN A GOOD 15
DEGREES BELOW NORMAL EVEN INTO SATURDAY.
FOR LATE SATURDAY INTO SUNDAY...SNOW CHANCES WOULD INCREASE AGAIN
AS LATEST MEDIUM RANGE GUIDANCE AND ENSEMBLES SHOW ANOTHER BUT
DEEPER TROUGH HEADED INTO THE SOUTHWEST U.S. WILL GO WITH ABOVE
CLIMATOLOGY POPS FOR THIS PERIOD GIVEN THE REASONABLE AGREEMENT IN
MODEL SOLUTION OF TROUGHINESS/FRONTAL PASSAGES.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 329 AM MST MON FEB 23 2015
THERE COULD BE SOME VERY LIGHT SNOW THRU 15Z HOWEVER NO
ACCUMULATIONS ARE EXPECTED. WK DENVER CYCLONE WAS OVER DIA EARLY
THIS MORNING AND MAY STAY NR THE AIRPORT THRU MIDDAY. WITH THIS TYPE
OF SITUATION ALWAYS HAVE TO BE AWARE OF SOME POTENTIAL FOG/STRATUS
HOWEVER HRRR KEEPS IT MAINLY WEST AND SOUTH DIA FOR NOW.
WINDS NEAR THE CYCLONE WILL BE VARIABLE AROUND 5KTS THIS MORNING.
BY MIDDAY THE WK CYCLONE MAY MOVE TO THE EAST OF NE OF DIA WITH
LIGHT NNW WINDS DEVELOPING. FOR TONIGHT WINDS SHOULD BECOME LIGHT
DRAINAGE BY EARLY EVENING. VFR CONDITIONS ARE EXPECTED THIS AFTN
AND TONIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM...BARJENBRUCH
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1043 PM MST SUN FEB 22 2015
.UPDATE...
ISSUED AT 800 PM MST SUN FEB 22 2015
STEADY ACCUMULATING SNOW IS NOT LIKELY ACROSS THE FAR E PLAINS AND
PER COORD WITH SURROUNDING WFO/S...I REMOVED THE HILITES FOR THAT
REGION. /HODANISH
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 251 PM MST SUN FEB 22 2015
...HEAVY SNOW OVER THE MOUNTAINS CONTINUES...
...SNOW WINDING DOWN TONIGHT FOR THE LOWER ELEVATIONS...
IN GENERAL...FORECAST IS WORKING OUT FAIRLY WELL ACROSS THE CWA.
FORECAST AMOUNTS FOR THE NORTHERN AND EASTERN ZONES WERE TOO
HIGH...AND TOO LOW FOR THE MTS AND SRN ZONES...BUT OVERALL AMOUNTS
ARE NOT TOO SURPRISING. AS THE UPPER TROUGH SHEARS OFF TO THE WEST
OVER CA...AND MID LEVEL WINDS CONTINUE TO VEER TO THE SW AND
W...WILL SEE SNOWFALL GRADUALLY DIMINISH OVER THE ERN PLAINS E OF I-
25 TONIGHT...SO HAVE REDUCED POPS THROUGH TONIGHT IN THAT AREA. WILL
LEAVE A SNOW ADVISORY GOING WITH ADDITIONAL LIGHT ACCUMS OF AN INCH
OR TWO POSSIBLE...AND CONTINUED ICY ROAD CONDITIONS. HIGH RES MODELS
ARE SHOWING THE HEAVIER SNOW GRADUALLY BEING TIED TO THE ERN MTS AND
HIGHER TRRN...AND THIS LOOKS REASONABLE. THERE COULD BE SOME BANDED
PRECIP SPILLING OVER TO PORTIONS OF THE I-25 CORRIDOR...ESPECIALLY W
OF I-25...THROUGH THIS EVENING...SO WILL LEAVE THE WARNING INTACT
FOR THE I-25 ZONES. IN FACT...THE HRRR CONTINUES TO SHOW SN PICKING
UP FOR A BIT EARLY THIS EVENING OVER EL PASO COUNTY BEFORE
DIMINISHING AFTER MIDNIGHT. LATER SHIFT CAN REEVALUATE AND
DOWNGRADE THE WARNING IF IT LOOKS LIKE THIS WILL NOT MATERIALIZE.
OVER THE MTS...SNOW CONTINUES THROUGH TOMORROW. WIND SENSOR IS OUT
AT KCPW...BUT AS MENTIONED IN THE EARLIER UPDATE BLIZZARD CONDITIONS
WERE OCCURRING THERE AND WILL LIKELY CONTINUE THROUGH PERIODS OF
MONDAY BEFORE THINGS BEGIN TO QUIET DOWN. LATEST GUIDANCE SUGGESTS
AN ADDITIONAL 2-3 FEET OVER THE SAN JUANS BY TUESDAY...SO WOULD NOT
BE SURPRISED TO SEE A FEW SPOTS NEAR 4 FEET BY THE TIME THIS
ENDS...AND WITH HIGH WINDS SOME SERIOUS DRIFTING AS
WELL...INCREASING AN UNSTABLE SNOW LOAD ON THE SLOPES AND RESULTING
IN EXTREME AVALANCHE THREAT OVER THE HIGH COUNTRY FOR THE NEXT FEW
DAYS.
INTERESTINGLY...LATEST GUIDANCE IS SHOWING H7 TEMPS OF MINUS 21
DEGREES OVER OUR AREA TONIGHT...SIGNIFICANTLY COLDER THAN WHAT THE
MODELS WERE SHOWING JUST A COUPLE OF DAYS AGO...AND IN LINE WITH THE
ECMWF GUIDANCE FROM A WEEK AGO! THE MUCH COLDER AIR HAS CUT BACK A
BIT ON DENDRITIC SNOW GROWTH...AND LIMITED SNOW AMOUNTS TO SOME
EXTENT FOR OUR ERN ZONES. AS A RESULT OF THE COLDER AIR
ALOFT...EXPECT SOME LOWS CLOSE TO ZERO TONIGHT EVEN WITH THE CLOUD
COVER...AND HAVE REDUCED HIGHS A BIT FOR TOMORROW WITH TEMPS
PROBABLY STAYING IN THE TEENS FOR THE MOST PART.
EXPECT GRADUAL IMPROVEMENT TOMORROW FOR THE PLAINS...AS WRLY FLOW
INCREASES. MODELS ARE SHOWING A LACK OF QPF THERE TOMORROW...BUT
WITH ABUNDANT LOW LEVEL MOISTURE AND CONTINUED SHALLOW UPSLOPE...AM
RELUCTANT TO REMOVE POPS COMPLETELY...SO WILL LEAVE LOW POPS IN
PLACE OVER THE PLAINS. OVER THE MTS...HEAVY SNOW CONTINUES AT TIMES
WITH BLIZZARD CONDITIONS FOR THE ERN SAN JUANS. SAN LUIS VALLEY WILL
BE BETWEEN THE TWO REGIMES AND COULD SEE SOME SHSN...BUT NOTHING
PARTICULARLY HEAVY EXPECTED. WELCOME BACK TO WINTER! ROSE
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 251 PM MST SUN FEB 22 2015
MONDAY NIGHT THE UPR LOW IS FORECAST TO MOVE EASTWARD FROM SRN
NV...WITH THE GFS SHOWING THE LOW CENTER OVR NERN AZ BY 12Z TUE AND
THE NAM BEING A LITTLE FARTHER WEST. EITHER WAY...SNOW CONTINUES OVR
THE SWRN CO MTNS. HOWEVER WITH THE GFS BEING FARTHER EAST THAN THE
NAM...PCPN IS ALSO FORECAST TO BE OVR THE SAN LUIS VALLEY AND THE
ERN MTNS...WHILE THE NAM HAS DRY CONDITIONS EVERY BUT THE SW MTNS.
ON TUE THE UPR LOW IS EXPECTED TO CONTINUE AN EASTWARD
TRACK...MOVING ACRS NRN NM...BRINGING MAINLY SOME PCPN CHANCES TO
MAINLY THE FAR SOUTHERN PORTIONS OF THE FORECAST AREA. HIGH TEMPS ON
TUE WL BE A LITTLE WARMER...BUT STILL BELOW AVERAGE...ESPECIALLY
WITH THE SNOW COVER.
TUE NIGHT AND EARLY WED DRY CONDITIONS ARE EXPECTED OVR THE AREA AS
THE UPR LOW MOVES INTO NORTHERN TX. A NEW UPR TROF DROPS INTO THE
STATE FROM THE SOUTH BY LATE WED MORNING...PUSHING MORE COLD AIR
INTO THE AREA. IN THE LATE MORNING OR EARLY AFTERNOON HOURS...PCPN
IS EXPECTED TO SPREAD SOUTH ACRS THE AREA AS WELL...WITH PROBABLY
THE HARDEST HIT AREAS BEING THE EASTERN MTS AND IMMEDIATELY ADJACENT
PLAINS AND THE PALMER DIVIDE. THE GFS AND ECMWF ARE IN PRETTY GOOD
AGREEMENT...KEEPING PCPN ACRS MUCH OF THE SERN PLAINS AND MTNS THRU
THU NIGHT AND MUCH OF FRI AS ANOTHER UPR DISTURBANCE MOVES INTO THE
AREA FROM THE PACIFIC NW. THIS WL BRING THE POTENTIAL FOR SEVERAL
INCHES OF SNOW OVR THE MTNS. UPSLOPE FLOW OVR ERN AREAS WL HELP TO
BRING SEVERAL INCHES TO THE THE WET MTNS...SOUTHERN SANGRES AND THE
ADJACENT PLAINS...WITH MAYBE A COUPLE TO A FEW INCHES ALONG THE I-25
CORRIDOR...AND LIGHTER ACCUMULATIONS OVR THE FAR SERN PLAINS.
UNSETTLE WEATHER IS FORECAST TO CONTINUE NEXT WEEKEND AS ANOTHER
UPR TROF AFFECTS THE STATE...KEEPING THE WEATHER COOL AND BRINGING
PCPN CHANCES TO MUCH OF THE AREA AND THE POTENTIAL FOR SEVERAL
INCHES OF SNOW IN THE MTNS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1042 PM MST SUN FEB 22 2015
MVFR AND IFR CONDITIONS TO CONTINUE AT COS AND PUB WITH LIGHT SNOW
AND FLURRIES ENDING AFT 12Z. LIGHT UPSLOPE FLOW AND ABUNDANT
MOISTURE OVER THE PAST FEW DAYS LOOKS TO KEEP MVFR CIGS IN PLACE
THROUGH THE AFTERNOON...WITH CLEARING SKIES AND VFR CONDITIONS
DEVELOPING THROUGH THE LATE AFTERNOON AND EARLY EVENING WITH
EXPECTED WEAK DOWNSLOPE FLOW.
MVFR AND IFR CONDITIONS WITH OCCASIONAL LIGHT SNOW AND FLURRIES
EXPECTED TO CONTINUE AT ALS THROUGH THE EARLY MORNING HOURS. MVFR
CIGS POSSIBLE THROUGH THE LATE MORNING WITH VFR CONDITIONS EXPECTED
TO DEVELOP THROUGH THE AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 5 AM MST MONDAY FOR COZ058>063-
072>088.
WINTER WEATHER ADVISORY UNTIL 5 PM MST MONDAY FOR COZ069>071.
WINTER STORM WARNING UNTIL 5 PM MST MONDAY FOR COZ064>067.
BLIZZARD WARNING UNTIL 11 PM MST MONDAY FOR COZ068.
&&
$$
UPDATE...HODANISH
SHORT TERM...28/ROSE
LONG TERM...28
AVIATION...MW
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
823 PM EST TUE FEB 24 2015
.UPDATE...WIDESPREAD LOW CLOUDS CONTINUE ACROSS THE AREA WITH
AREAS OF DRIZZLE. RADAR SHOWS A FEW BANDS OF LIGHT SHOWERS OVER
THE AREA...WHICH THE HRRR SUGGESTS WILL CONTINUE THRU MUCH OF THE
NIGHT. MADE SOME SMALL ADJUSTMENTS TO HOURLY POP AND WEATHER
GRIDS BASED ON THIS. CLOUDS WILL KEEP TEMPS UP...CURRENT LOW TEMP
FORECAST LOOKS FINE.
DURING DAY WED...SURFACE LOW INTENSIFIES IN NE GULF OF MEX WITH
WARM SECTOR SURGING NORTHWARD OVER NRN FL PENINSULA...WITH NE FL
IN WARM SECTOR TOMORROW EVENING. CORRECTED DIURNAL TEMP PATTERN
FOR WED AFTERNOON THRU NIGHT TO REFLECT STEADY OR SLOWLY RISING
TEMPS THRU THE EVENING IN WARM SECTOR...WITH TEMPS FALLING AFTER
COLD FRONT PASSES LATE WED NIGHT.
&&
.AVIATION...IFR CIGS IN PLACE OVER THE AREA...EXCEPT SMALL BREAK
AROUND GNV/OCF...WHICH MAY NOT LAST MUCH LONGER. IFR CONDITIONS
EXPECTED TO REMAIN THRU WED MORNING...WITH SOME IMPROVEMENT TO
MVFR POSSIBLE IN AFTERNOON AS WARM FRONT APPROACHES FROM THE
SOUTH.
&&
.MARINE...AVAILABLE GUIDANCE SUGGESTS CONDITIONS BELOW ADVISORY
CRITERIA IN OFFSHORE COMPONENT...THOUGH MAY BE CLOSE NEAR GULF
STREAM. WILL DROP ADVISORY IN UPDATE.
RIP CURRENTS: MODERATE RISK WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 41 55 43 55 / 20 100 90 20
SSI 43 52 46 54 / 30 80 90 40
JAX 47 57 51 60 / 30 60 90 60
SGJ 50 60 56 61 / 20 40 90 70
GNV 51 64 57 63 / 30 40 90 60
OCF 53 69 59 66 / 30 40 80 70
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR WATERS FROM
ALTAMAHA SOUND GA TO FERNANDINA BEACH FL FROM 20 TO 60 NM-
WATERS FROM FERNANDINA BEACH TO ST. AUGUSTINE FL FROM 20 TO
60 NM-WATERS FROM ST. AUGUSTINE TO FLAGLER BEACH FL FROM 20
TO 60 NM.
&&
$$
WOLF/PETERSON/WALSH
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
544 AM EST MON FEB 23 2015
.UPDATE...WIDESPREAD DENSE FOG OVER WESTERN FLORIDA PENINSULA IS
SLOWLY ADVECTING EASTWARD AND MOVING INTO LAKE COUNTY EARLY THIS
MORNING BASED ON LATEST SATELLITE AND SFC OBS. NOT QUITE SURE HOW
FAR EASTWARD THIS MORE WIDESPREAD FOG WILL BE ABLE TO TRAVEL
BEFORE DAYTIME HEATING BEGINS TO SET IN THIS MORNING. FOR NOW
HAVE JUST DECIDED TO ISSUE A DENSE FOG ADVISORY FOR LAKE
COUNTY...BUT WILL CONTINUE TO MONITOR FOR ANY ADDITIONAL
EXPANSION.
&&
.PREV DISCUSSION... /ISSUED 348 AM EST MON FEB 23 2015/
DISCUSSION...
TODAY/TONIGHT...COLD FRONT CURRENTLY JUST NORTH OF FL WILL WEAKEN AS
IT SHIFTS SWEETHEART AND EVENTUALLY INTO THE AREA TONIGHT. ANY
FOG/STRATUS INITIALLY OVER THE REGION WILL BURN OFF BY LATE MORN
WITH PARTLY CLOUDY SKIES EXPECTED THROUGH MUCH OF THE DAY. TEMPS
WILL REMAIN ABOVE NORMAL WITH HIGHS RANGING FROM THE UPPER 70S OVER
LAKE AND VOLUSIA COUNTY TO LOW 80S FARTHER SOUTH. MODELS SHOW A
LITTLE HIGHER MOISTURE WORKING INTO NRN AREAS LATER IN THE AFT AHEAD
OF THE FRONT WHICH MAY LEAD TO A FEW SHRAS...SO HAVE INCLUDED SLIGHT
CHANCE POPS NORTH OF ORLANDO. THE LATEST HRRR INDICATES SOME ISO
SHRA ACTIVITY EVEN FARTHER SOUTH BY LATE DAY BUT LOW LEVEL MOISTURE
IS FAIRLY SHALLOW AND MOS POPS REMAIN BELOW MENTIONABLE LEVELS SO
WILL KEEP RAIN CHANCES OUT OF THE FORECAST ELSEWHERE.
AS FRONT MOVES INTO CENTRAL FLORIDA TONIGHT RAIN CHANCES WILL
CONTINUE TO INCREASE SLIGHTLY MAINLY OVER NORTHERN PORTIONS OF THE
AREA. ALSO CLOUD COVER WILL INCREASE AS LOW CLOUD DECK BUILDS IN
BEHIND THE BOUNDARY. SINCE FRONT WILL BE WEAK...OVERNIGHT TEMPS WILL
STAY ABOVE NORMAL WITH LOWS IN THE UPPER 50S TO LOW 60S.
TUE...WEAK COLD FRONT SHOULD SHIFT TO THE SOUTHERN SECTIONS.
FORECAST SOUNDINGS SHOW A SHALLOW COOL AIR MASS WITH CONSIDERABLE
LOW CLOUDINESS ESPECIALLY ACROSS THE NORTH HALF. ISENTROPIC LIFT
WILL BE SHALLOW/WEAK SO EXPECT ONLY SCATTERED LIGHT PRECIP. MAX
TEMPS WILL BE KNOCKED DOWN CONSIDERABLY ACROSS THE NORTH WITH THE
CLOUD COVER AND NORTHERLY WIND FLOW. SOUTHERN SECTIONS WILL HAVE A
LITTLE MORE CLOUDINESS DEVELOPING IN THE AFTERNOON BUT MAX TEMPS
SHOULD STILL BE 80 AROUND OKEECHOBEE.
TUE NIGHT...A WEAK LOW EAST OF THE COASTAL WATERS IS FORECAST TO
PULL AWAY TO THE NORTHEAST BUT THE WEAK/SHALLOW FRONTAL BOUNDARY
SHOULD CONTINUE TO EXTEND ACROSS THE SOUTHERN PENINSULA. MOS POPS
ARE 20-30 PERCENT...BUT THE MAIN CONCERN MAY ACTUALLY TURN OUT TO
BE LOW STRATUS/FOG. WILL NOT MENTION YET AND KEEP POPS AT 20
PERCENT OR LESS.
WED-THU...THE 00Z GFS/ECMWF HAVE COME INTO GOOD AGREEMENT DURING
THIS PERIOD. THE MAIN FEATURE WILL BE A SOUTHERN STREAM SHORTWAVE
TROUGH THAT MOVES ACROSS THE DEEP SOUTH WED WHILE GRADUALLY
DAMPENING OUT. THE ACCOMPANYING SURFACE LOW IS FORECAST TO PUSH
INTO NORTH FLORIDA WED AFTERNOON AND SHIFT TO OFFSHORE THE
CAROLINAS BY 12Z THU.
THE WARM SECTOR WILL ENCOMPASS THE LOCAL AREA AS LOW LEVEL WINDS
BECOME SOUTHERLY AND INCREASE WED INTO WED NIGHT. THE MODELS SHOW
MAIN PRECIP OCCURRING NEAR A WARM FRONT TO OUR NORTH ON WED THEN
AS COLD FRONT DROPS TOWARDS THE AREA OVERNIGHT...A BAND OF
CONVECTION WILL ACCOMPANY IT. THE BAND OF CONVECTION SHOULD SHIFT
INTO SOUTHERN SECTIONS ON THU.
HAVE NOT MADE MUCH CHANGE TO THE PREVIOUS FORECAST WHICH HAS
CHANCE POPS NORTH AND SLIGHT CHANCE IN THE SOUTH WED AND WED
NIGHT...EXCEPT BECOMING LIKELY IN THE NORTH WED NIGHT. CHANCE
POPS SHOULD BE A LITTLE HIGHER IN THE SOUTH ON THU.
WITH QUITE STRONG LOW LEVEL WINDS AS SURFACE LOW MOVES BY JUST TO
OUR NORTH...THE MENTION OF ISOLATED STORMS LOOKS GOOD WED NIGHT
ESPECIALLY NORTH HALF...WITH A SLIGHT CHANCE THAT STORMS COULD BE
STRONG.
FRI-NEXT MON...LARGE HIGH PRESSURE CENTERED OVER THE MID PART OF
THE COUNTRY SHOULD PUSH FRONTAL BOUNDARY INTO THE NORTHERN BAHAMAS
ON FRI BUT THE MODELS SHOW FRONT HANGING UP AND THE ASSOCIATED
MOISTURE FROM IT LIFTING BACK NORTH. THIS WILL ALLOW A MENTION OF
SLIGHT CHANCE TO CHANCE POPS THROUGH THE WEEKEND.
TEMPERATURES GENERALLY EXPECTED TO STAY NEAR TO JUST BELOW SEASONAL
NORMS FRI THEN MODERATE SAT AS BREEZY ONSHORE FLOW DEVELOPS...THEN
BE ABOVE NORMAL BY SUN AS BREEZY ONSHORE CONTINUES. A DEEP LAYER
HIGH PRESSURE RIDGE IS INDICATED OVER THE AREA NEXT MON...SO A
WARM AND DRY DAY LOOKS TO BE ON TAP.
&&
AVIATION...PATCHY/AREAS OF FOG THROUGH EARLY MORNING WILL PRODUCE
TEMPO IFR/MVFR CONDS THROUGH 13-14Z. ANY FOG SHOULD THEN BURN OFF
WITH VFR CONDS EXPECTED INTO THE AFT. WEAK FRONT MOVING INTO THE
REGION TONIGHT WILL USHER IN A LOWER CLOUD DECK WITH IFR/LIFR CIGS
BUILDING SOUTHWARD OVER THE REGION AS PER LATEST MOS GUIDANCE. SOME
PATCHY FOG MAY ALSO BE POSSIBLE BUT AT THIS TIME NOT EXPECTING
WIDESPREAD LOWER VISIBILITIES.
RAIN CHANCES WILL INCREASE SLIGHTLY INTO LATE DAY AND TONIGHT WITH
THE FRONT BUT POPS ARE LOW ENOUGH TO KEEP MENTION OUT OF THE TAFS
FOR NOW.
&&
MARINE...
TODAY/TONIGHT...LIGHT TO GENTLE BREEZE EXPECTED TODAY OVER THE
WATERS WITH WINDS INITIALLY OUT OF THE W/SW BECOMING MORE NORTHERLY
AND INCREASING INTO TONIGHT AS A WEAK FRONT MOVES THROUGH THE
REGION.
NORTHERLY SURGE DOES NOT APPEAR AS STRONG AS IT HAD IN PREVIOUS
MODEL RUNS WITH WIND SPEEDS GENERALLY AROUND 15 KNOTS. SEAS BUILDING
TO 6 FEET OVER THE OFFSHORE WATERS NORTH OF THE CAPE BY LATE TONIGHT
STILL LOOKS REASONABLE...SO WILL MAINTAIN THESE WAVE HEIGHTS IN THE
FORECAST.
TUE-FRI...A VERY PROGRESSIVE WEATHER PATTERN WILL LEAD TO QUICKLY
CHANGING WIND FIELDS THROUGH THE PERIOD. A WEAK LOW IS FORECAST
JUST EAST OF THE WATERS TUE WHICH SHOULD PRODUCE A BRIEF PERIOD OF
NORTHERLY WINDS 15-20 KNOTS. THEN ON WED...THE WINDS SHOULD START
OFF LIGHT AND BECOME SOUTHERLY WHILE INCREASING...AS A SURFACE
LOW MOVES TOWARDS NORTH FLORIDA. THE LOW WILL LIFT QUICKLY
NORTHEAST AND SWING A COLD FRONT INTO THE WATERS THU. IN ADDITION
TO INCREASED RAIN CHANCES WED NIGHT AND THU...BREEZY SOUTHERLY
FLOW WILL BECOME NORTHERLY BEHIND THE FRONT THU NIGHT AND CONTINUE
INTO FRI.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR NORTHERN
LAKE COUNTY-SOUTHERN LAKE COUNTY.
AM...NONE.
&&
$$
UPDATE/SHORT TERM...WEITLICH
LONG TERM....LASCODY
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
350 AM EST MON FEB 23 2015
.DISCUSSION...
TODAY/TONIGHT...COLD FRONT CURRENTLY JUST NORTH OF FL WILL WEAKEN AS
IT SHIFTS SWEETHEART AND EVENTUALLY INTO THE AREA TONIGHT. ANY
FOG/STRATUS INITIALLY OVER THE REGION WILL BURN OFF BY LATE MORN
WITH PARTLY CLOUDY SKIES EXPECTED THROUGH MUCH OF THE DAY. TEMPS
WILL REMAIN ABOVE NORMAL WITH HIGHS RANGING FROM THE UPPER 70S OVER
LAKE AND VOLUSIA COUNTY TO LOW 80S FARTHER SOUTH. MODELS SHOW A
LITTLE HIGHER MOISTURE WORKING INTO NRN AREAS LATER IN THE AFT AHEAD
OF THE FRONT WHICH MAY LEAD TO A FEW SHRAS...SO HAVE INCLUDED SLIGHT
CHANCE POPS NORTH OF ORLANDO. THE LATEST HRRR INDICATES SOME ISO
SHRA ACTIVITY EVEN FARTHER SOUTH BY LATE DAY BUT LOW LEVEL MOISTURE
IS FAIRLY SHALLOW AND MOS POPS REMAIN BELOW MENTIONABLE LEVELS SO
WILL KEEP RAIN CHANCES OUT OF THE FORECAST ELSEWHERE.
AS FRONT MOVES INTO CENTRAL FLORIDA TONIGHT RAIN CHANCES WILL
CONTINUE TO INCREASE SLIGHTLY MAINLY OVER NORTHERN PORTIONS OF THE
AREA. ALSO CLOUD COVER WILL INCREASE AS LOW CLOUD DECK BUILDS IN
BEHIND THE BOUNDARY. SINCE FRONT WILL BE WEAK...OVERNIGHT TEMPS WILL
STAY ABOVE NORMAL WITH LOWS IN THE UPPER 50S TO LOW 60S.
TUE...WEAK COLD FRONT SHOULD SHIFT TO THE SOUTHERN SECTIONS.
FORECAST SOUNDINGS SHOW A SHALLOW COOL AIR MASS WITH CONSIDERABLE
LOW CLOUDINESS ESPECIALLY ACROSS THE NORTH HALF. ISENTROPIC LIFT
WILL BE SHALLOW/WEAK SO EXPECT ONLY SCATTERED LIGHT PRECIP. MAX
TEMPS WILL BE KNOCKED DOWN CONSIDERABLY ACROSS THE NORTH WITH THE
CLOUD COVER AND NORTHERLY WIND FLOW. SOUTHERN SECTIONS WILL HAVE A
LITTLE MORE CLOUDINESS DEVELOPING IN THE AFTERNOON BUT MAX TEMPS
SHOULD STILL BE 80 AROUND OKEECHOBEE.
TUE NIGHT...A WEAK LOW EAST OF THE COASTAL WATERS IS FORECAST TO
PULL AWAY TO THE NORTHEAST BUT THE WEAK/SHALLOW FRONTAL BOUNDARY
SHOULD CONTINUE TO EXTEND ACROSS THE SOUTHERN PENINSULA. MOS POPS
ARE 20-30 PERCENT...BUT THE MAIN CONCERN MAY ACTUALLY TURN OUT TO
BE LOW STRATUS/FOG. WILL NOT MENTION YET AND KEEP POPS AT 20
PERCENT OR LESS.
WED-THU...THE 00Z GFS/ECMWF HAVE COME INTO GOOD AGREEMENT DURING
THIS PERIOD. THE MAIN FEATURE WILL BE A SOUTHERN STREAM SHORTWAVE
TROUGH THAT MOVES ACROSS THE DEEP SOUTH WED WHILE GRADUALLY
DAMPENING OUT. THE ACCOMPANYING SURFACE LOW IS FORECAST TO PUSH
INTO NORTH FLORIDA WED AFTERNOON AND SHIFT TO OFFSHORE THE
CAROLINAS BY 12Z THU.
THE WARM SECTOR WILL ENCOMPASS THE LOCAL AREA AS LOW LEVEL WINDS
BECOME SOUTHERLY AND INCREASE WED INTO WED NIGHT. THE MODELS SHOW
MAIN PRECIP OCCURRING NEAR A WARM FRONT TO OUR NORTH ON WED THEN
AS COLD FRONT DROPS TOWARDS THE AREA OVERNIGHT...A BAND OF
CONVECTION WILL ACCOMPANY IT. THE BAND OF CONVECTION SHOULD SHIFT
INTO SOUTHERN SECTIONS ON THU.
HAVE NOT MADE MUCH CHANGE TO THE PREVIOUS FORECAST WHICH HAS
CHANCE POPS NORTH AND SLIGHT CHANCE IN THE SOUTH WED AND WED
NIGHT...EXCEPT BECOMING LIKELY IN THE NORTH WED NIGHT. CHANCE
POPS SHOULD BE A LITTLE HIGHER IN THE SOUTH ON THU.
WITH QUITE STRONG LOW LEVEL WINDS AS SURFACE LOW MOVES BY JUST TO
OUR NORTH...THE MENTION OF ISOLATED STORMS LOOKS GOOD WED NIGHT
ESPECIALLY NORTH HALF...WITH A SLIGHT CHANCE THAT STORMS COULD BE
STRONG.
FRI-NEXT MON...LARGE HIGH PRESSURE CENTERED OVER THE MID PART OF
THE COUNTRY SHOULD PUSH FRONTAL BOUNDARY INTO THE NORTHERN BAHAMAS
ON FRI BUT THE MODELS SHOW FRONT HANGING UP AND THE ASSOCIATED
MOISTURE FROM IT LIFTING BACK NORTH. THIS WILL ALLOW A MENTION OF
SLIGHT CHANCE TO CHANCE POPS THROUGH THE WEEKEND.
TEMPERATURES GENERALLY EXPECTED TO STAY NEAR TO JUST BELOW SEASONAL
NORMS FRI THEN MODERATE SAT AS BREEZY ONSHORE FLOW DEVELOPS...THEN
BE ABOVE NORMAL BY SUN AS BREEZY ONSHORE CONTINUES. A DEEP LAYER
HIGH PRESSURE RIDGE IS INDICATED OVER THE AREA NEXT MON...SO A
WARM AND DRY DAY LOOKS TO BE ON TAP.
&&
.AVIATION...PATCHY/AREAS OF FOG THROUGH EARLY MORNING WILL PRODUCE
TEMPO IFR/MVFR CONDS THROUGH 13-14Z. ANY FOG SHOULD THEN BURN OFF
WITH VFR CONDS EXPECTED INTO THE AFT. WEAK FRONT MOVING INTO THE
REGION TONIGHT WILL USHER IN A LOWER CLOUD DECK WITH IFR/LIFR CIGS
BUILDING SOUTHWARD OVER THE REGION AS PER LATEST MOS GUIDANCE. SOME
PATCHY FOG MAY ALSO BE POSSIBLE BUT AT THIS TIME NOT EXPECTING
WIDESPREAD LOWER VISIBILITIES.
RAIN CHANCES WILL INCREASE SLIGHTLY INTO LATE DAY AND TONIGHT WITH
THE FRONT BUT POPS ARE LOW ENOUGH TO KEEP MENTION OUT OF THE TAFS
FOR NOW.
&&
.MARINE...
TODAY/TONIGHT...LIGHT TO GENTLE BREEZE EXPECTED TODAY OVER THE
WATERS WITH WINDS INITIALLY OUT OF THE W/SW BECOMING MORE NORTHERLY
AND INCREASING INTO TONIGHT AS A WEAK FRONT MOVES THROUGH THE
REGION.
NORTHERLY SURGE DOES NOT APPEAR AS STRONG AS IT HAD IN PREVIOUS
MODEL RUNS WITH WIND SPEEDS GENERALLY AROUND 15 KNOTS. SEAS BUILDING
TO 6 FEET OVER THE OFFSHORE WATERS NORTH OF THE CAPE BY LATE TONIGHT
STILL LOOKS REASONABLE...SO WILL MAINTAIN THESE WAVE HEIGHTS IN THE
FORECAST.
TUE-FRI...A VERY PROGRESSIVE WEATHER PATTERN WILL LEAD TO QUICKLY
CHANGING WIND FIELDS THROUGH THE PERIOD. A WEAK LOW IS FORECAST
JUST EAST OF THE WATERS TUE WHICH SHOULD PRODUCE A BRIEF PERIOD OF
NORTHERLY WINDS 15-20 KNOTS. THEN ON WED...THE WINDS SHOULD START
OFF LIGHT AND BECOME SOUTHERLY WHILE INCREASING...AS A SURFACE
LOW MOVES TOWARDS NORTH FLORIDA. THE LOW WILL LIFT QUICKLY
NORTHEAST AND SWING A COLD FRONT INTO THE WATERS THU. IN ADDITION
TO INCREASED RAIN CHANCES WED NIGHT AND THU...BREEZY SOUTHERLY
FLOW WILL BECOME NORTHERLY BEHIND THE FRONT THU NIGHT AND CONTINUE
INTO FRI.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 78 59 64 52 / 20 30 40 20
MCO 82 61 73 57 / 10 20 30 20
MLB 80 61 72 58 / 10 20 20 30
VRB 81 60 77 58 / 10 10 20 20
LEE 79 59 67 55 / 10 20 40 20
SFB 80 60 68 55 / 20 20 40 20
ORL 81 60 71 57 / 10 20 30 20
FPR 82 60 78 58 / 10 10 20 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...WEITLICH
LONG TERM....LASCODY
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
636 AM EST MON FEB 23 2015
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE REGION TODAY AND BECOME STATIONARY
SOUTH OF THE AREA TONIGHT. DEVELOPING LOW PRESSURE WILL TRACK ALONG
THE STATIONARY FRONT OVER THE ATLANTIC TUESDAY. HIGH PRESSURE WILL
BRIEFLY BUILD IN TUESDAY NIGHT INTO EARLY WEDNESDAY...FOLLOWED BY
STRONGER LOW PRESSURE FROM THE GULF OF MEXICO THAT PASSES OFFSHORE
WEDNESDAY NIGHT. STRONG HIGH PRESSURE CENTERED NORTH OF THE AREA
WILL EXPAND TO BECOME THE PRIMARY FEATURE LATE WEEK INTO NEXT
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
TODAY...SHORTWAVE ENERGY EMBEDDED WITHIN THE NEARLY ZONAL FLOW ALOFT
IS HELPING PROVIDE SOME UPPER SUPPORT FOR LOW LEVEL FORCING ALONG A
COLD FRONT THAT STRETCHES FROM EASTERN NORTH CAROLINA BACK TO THE
LOWER MISSISSIPPI VALLEY. THE RESULT IS A LARGE BAND OF WIDESPREAD
RAINFALL THAT IS IMPACTING MUCH OF THE NORTHERN HALF OF THE FORECAST
AREA THIS MORNING. POPS THROUGH THE REMAINDER OF THE MORNING FEATURE
100 POPS TO THE NORTH...RANGING TO SLIGHT CHANCES FAR TO THE SOUTH
AROUND MCINTOSH COUNTY. THE BEST FORCING WILL REMAIN FOCUSED TO THE
NORTH AND THAT IS WHERE THE HEAVIEST RAIN WILL FALL. THEN FOLLOWING
THE RECENT RUNS OF THE HRRR AND THE RAP...THE BULK OF THE
PRECIPITATION WILL COME TO AN END FROM WEST TO EAST IN THE LATE
MORNING TO EARLY AFTERNOON HOURS. TEMPERATURES ARE CURRENTLY QUITE
MILD ACROSS THE REGION...MAINLY IN THE UPPER 50S AND LOW 60S. THESE
VALUES WILL REMAIN STEADY THROUGH DAYBREAK...AND ONLY BEGIN TO FALL
WITH THE SOUTHWARD PROGRESSION OF THE COLD FRONT. BASED ON THE
TIMING IN THE HRRR AND RAP...THE WIND SHIFT AND ASSOCIATED
INFILTRATION OF COOLER AIR WILL BEGIN TAKING PLACE AROUND 13Z OR SO.
HIGH TEMPERATURES FOR THE DAY WILL OCCUR JUST BEFORE THE FRONT
BEGINS ITS SOUTHWARD MARCH...WITH MID 50S IN MOST AREAS AND EVEN
SOME UPPER 50S AND LOW 60S POSSIBLE FOR SOUTHEAST GEORGIA.
TEMPERATURES WILL THEN STEADILY FALL THROUGH THE DAY.
TONIGHT...THE COLD FRONT WILL BECOME NEARLY STATIONARY TO THE SOUTH
AND SOUTHEAST OF THE REGION AS HIGH PRESSURE BEGINS TO BRIDGE ACROSS
THE OHIO VALLEY AND INTO THE MID ATLANTIC. BY LATE TONIGHT...THE
HIGH WILL SETTLE INTO COLD AIR DAMMING POSITION WITH INCREASINGLY
COOL AIR OOZING IN FROM THE NORTHEAST. EARLY IN THE TONIGHT
PERIOD...THE MODELS GENERALLY SHOW A PRECIPITATION LULL PERIOD AS
THE FORCING ALONG THE FRONT IS DISPLACED TO THE SOUTH AND SOUTHEAST
AND THE UPPER SUPPORT WANES. HOWEVER...BY VERY LATE TONIGHT THE NOSE
OF A 80-90 KT 500 MB JET PUSHES IN FROM THE EAST COINCIDENT WITH AN
AREA OF SHALLOW LOW LEVEL ISENTROPIC LIFT. SOME OF THE MODELS SHOW
PRECIPITATION BREAKING OUT CLOSER TO SUNRISE AT THE SAME TIME AS SUB
FREEZING AIR FILTERS IN FROM THE NORTHEAST. SOUNDINGS SHOW THAT
WHATEVER PRECIPITATION DOES FALL WILL LIKELY FALL AS FREEZING
RAIN/DRIZZLE AND THROUGH THE VERY LATE TONIGHT PERIOD WILL MAINLY
IMPACT THE EXTREME NORTH...ALONG AND NEAR THE SANTEE RIVER. THE BULK
OF THIS EVENT WILL THEN OCCUR INTO TUESDAY MORNING. BY LATE
TONIGHT...LOWS WILL REACH THE LOW 30S FOR MUCH OF SOUTHEAST SOUTH
CAROLINA WITH MID TO UPPER 30S IN SOUTHEAST GEORGIA.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
TUESDAY...THE STALLED OUT FRONT AND ITS ASSOCIATED BAROCLINIC ZONE
WILL BE FOUND NOT FAR OFF THE SE COAST. CHANNELED VORTICITY ARRIVING
IN THE FAST MOVING AND BROADLY CYCLONIC FLOW ALOFT WILL TRIGGER
CYCLOGENESIS A COUPLE HUNDRED MILES OFF THE NE FLORIDA COAST. AT THE
SAME TIME...UPPER DIVERGENCE/DIFLUENCE ASSOCIATED WITH THE EXIT
REGION OF A ROBUST 130 KT JET AND ISENTROPIC ASCENT ON MAINLY THE
280K AND 285K SURFACES /AROUND 1500-2500 FT/ WILL COMBINE WITH
PRODUCE AN EXPANDING AREA OF RAIN ACROSS THE FORECAST AREA. THERE
STILL REMAINS SOME DISPARITIES BETWEEN THE VARIOUS MODEL
GUIDANCE...BUT WE HAVE LEANED TOWARD A SOLUTION MOST SIMILAR TO A
BLEND OF THE NAM...ECMWF AND CANADIAN MODELS AS OPPOSED TO THE GFS.
COLDER AIR WILL BE FILTERING INTO THE REGION AS A TRANSIENT HIGH
PRESSURE WEDGE DEVELOPS BEHIND THE COLD FRONT STALLED OFFSHORE. THIS
WILL CAUSE A CONCERN FOR THE POTENTIAL FOR FREEZING RAIN AND DRIZZLE
OVER SEVERAL PARTS OF THE FORECAST AREA. SOUNDING DATA REVEALS THAT
THE BEST CHANCE FOR FREEZING SURFACE TEMPS AND/OR WET BULBS WILL
OCCUR MAINLY INLAND FROM US-17 IN SC AND OVER JENKINS AND SCREVEN
COUNTIES IN SE GA. THIS INCLUDES PARTS OF THE CHARLESTON AND
BEAUFORT METRO AREAS...AND IT IS IN THESE LOCATIONS WHERE WE HAVE
GONE AHEAD WITH A FREEZING RAIN ADVISORY FROM 4 AM UNTIL 2 PM
TUESDAY. WHILE IT IS CERTAINLY COLD ENOUGH FOR ICE/SNOW
ALOFT...THERE IS A PRONOUNCED WARM NOSE AROUND 900-750 MB WHICH WILL
TURN WILL ALLOW FOR MELTING OF THE FROZEN PRECIP. BUT THERE IS
ENOUGH MOISTURE AND COLDER AIR BELOW TO ALLOW FOR THE LIQUID DROPS
TO REFREEZE. THERE CAN CERTAINLY BE SOME SLEET MIXED IN...BUT THE
BULK OF THE PRECIP LOOKS TO BE FREEZING RAIN AND/OR DRIZZLE. OUR
CONFIDENCE ON THE AMOUNT OF ICING IS MODERATE AT BEST...SINCE WE
HAVE HAD A SHORT DURATION WARM SPELL AND MUCH OF THE PRECIP MAY TURN
OUT BE RATHER LIGHT IN INTENSITY. THAT SAID...WE DO ANTICIPATE A FEW
HUNDREDTHS OF AN INCH OF FREEZING RAIN ON VARIOUS SURFACES. KEEP IN
MIND THAT THE TALLER BRIDGES OF THE AREA CAN FREEZE BEFORE ROAD
SURFACES. THE DON HOLT BRIDGE IN THE CHARLESTON AREA PROBABLY HAS
THE BEST CHANCE OF EXPERIENCING ANY ICING PROBLEMS TUESDAY
MORNING...BUT WE CAN/T ENTIRELY DISCOUNT THE RAVENEL AND WANDO
BRIDGES ALSO GETTING SOME ICE ON THEM. DEPENDING UPON THE INTENSITY
OF THE PRECIP WE MAY NEED TO EXPAND THE ADVISORY A LITTLE FURTHER
SOUTH INTO GEORGIA AT A LATER TIME. TEMPS LOOK TO BE ABOVE FREEZING
IN THE EARLY TO MID AFTERNOON...THUS ANY FREEZING PRECIP WILL CHANGE
OVER TO LIQUID BEFORE TAPERING OFF LATE.
FOR NOW WE BELIEVE THAT THE PRECIP OVER MUCH OF SE GA...ESPECIALLY
TO THE SOUTH OF I-16 WILL BE ALL OR MAINLY LIQUID WITH QPF/S OF 1/10
TO 1/4 INCH TO OCCUR. TEMPS WON/T GO MUCH OF ANYWHERE...EVEN
DROPPING A COUPLE OF DEGREES DUE TO THE PRECIP...AND WE/LL BE MAINLY
IN THE LOWER AND MIDDLE 30S NORTH/NW TO THE LOWER 40S SOUTH.
TUESDAY NIGHT...THE SURFACE WAVE OVER THE ATLANTIC AND THE
ASSOCIATED FORCING PULL AWAY AS A MESO-HIGH BUILDS FROM THE WEST.
THIS WILL TEMPORARILY SHUT OFF THE PRECIP...AND WE WILL NEED TO
WATCH FOR POSSIBLE RE-FREEZING OF THE EARLIER RAINS...ESPECIALLY OVER
THE CHARLESTON QUAD-COUNTY DISTRICT.
WEDNESDAY AND WEDNESDAY NIGHT...A POTENT SHORT WAVE IN THE DESERT SW
TODAY WILL SHIFT THROUGH THE SOUTHERN PLAINS WEDNESDAY AND HEADS
INTO THE SE AT NIGHT. THIS TRIGGERS SURFACE CYCLOGENESIS IN THE
NORTHERN GULF OF MEXICO BEFORE THE LOW TRACKS JUST OFF THE LOCAL
COASTS BY LATE IN THE PERIOD. LARGE SCALE FORCING FROM THESE
FEATURES AND A POWERFUL WEST-EAST 150 KT UPPER JET WILL ALLOW FOR
CONSIDERABLE OVER-RUNNING RAINS TO DEVELOP BY WEDNESDAY
AFTERNOON...BEFORE TAPERING OFF FROM WEST/SW TO EAST/NE LATE
WEDNESDAY NIGHT. THIS PROMISES TO BE A PRETTY GOOD SOAKER...WITH
PWATS OF 1-1.5 INCHES TO PREVAIL. SOME PLACES COULD EASILY ACHIEVE
THESE AMOUNTS GIVEN THAT WE ARE CARRYING CATEGORICAL POPS. RIGHT
NOW IT LOOKS TO BE ALL LIQUID UNLESS THE OVER-RUNNING RAINS ARRIVE
EARLIER THAN EXPECTED. TEMPS WILL REMAIN FAR BELOW NORMAL.
THURSDAY...MUCH DRIER AIR OVERSPREADS THE REGION BEHIND THE EXITING
SHORT AVE AND SURFACE LOW...LEADING TO A DRY BUT CHILLY DAY WITH
TEMPS AGAIN FAR BELOW SEASONAL NORMS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
A HUMONGOUS AND ROBUST 1040 MB CANADIAN HIGH BUILDING OUT OF THE
GREAT PLAINS WILL EXPAND EAST AND SOUTH AND COVERS MUCH OF THE
NATION EAST OF THE ROCKIES...INCLUDING THE LOCAL AREA. THIS LEADS TO
DRY AND CHILLY CONDITIONS INTO FRIDAY...BEFORE THE HIGH SHIFTS INTO
THE ATLANTIC OVER THE WEEKEND AND EARLY NEXT WEEK AND TEMPS BEGIN TO
MODERATE. A COASTAL TROUGH WILL LIKELY FORM DURING THIS TRANSITION
JUST OFF OUR COAST...AND WE LOOK FOR AT LEAST A SMALL CHANCE OF
SHOWERS IN RESPONSE.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
KCHS...MVFR OR LOWER CONDITIONS WILL PREVAIL THROUGH 12Z TUESDAY.
LOOKING AT NEARBY OBSERVATIONAL SITES THERE WILL EVEN BE PERIODS
OF IFR OR LOWER WEATHER INTO THIS AFTERNOON. MEANWHILE...A SHORT
WAVE WILL BRUSH THE TERMINAL DURING THE MID MORNING INTO THIS
AFTERNOON...BRINGING WITH IT LIGHT TO PERHAPS RAIN. ALTHOUGH WE
CAN/T RULE OUT A LITTLE DRIZZLE LATE THIS AFTERNOON INTO
TONIGHT...A GREATER RISK FOR DRIZZLE WILL OCCUR CLOSER TO DAYBREAK
TUESDAY. IF IT/S COLD ENOUGH IT MIGHT EVEN BE FREEZING DRIZZLE.
LIGHT WINDS THIS MORNING WILL VEER AROUND TO THE NORTH AND
INCREASE IN WAKE OF A COLD FRONT AROUND 17Z...REMAINING GUSTY
THROUGH THE BALANCE OF THE TAF CYCLE.
KSAV...VFR CONDITIONS THIS MORNING WILL BE SHORT-LIVED AS LOWER
CLOUD DECKS ARRIVE FROM THE NORTH IN RESPONSE TO AN APPROACHING
COLD FRONT. THE FRONT WILL BE ACCOMPANIED BY A LITTLE LIGHT
RAIN...BUT A MORE NOTICEABLE CHANGE WILL BE WINDS BECOMING
NORTH/NE AND GUSTY INTO TONIGHT WITH SUB-VFR WEATHER TO AGAIN
PREVAIL. COULD SEE SOME LIGHT RAINS LATE IN THE PERIOD...BUT A
BETTER CHANCE AFTER 12Z TUESDAY.
EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS OF VARYING
CATEGORIES WILL CONTINUE MUCH OF THE TIME TUESDAY INTO
THURSDAY...ALTHOUGH INTERLUDES OF VFR ARE POSSIBLE BETWEEN RAIN
EVENTS. ALSO OF NOTE...THERE IS A GOOD CHANCE FOR FREEZING/FROZEN
PRECIPITATION TUESDAY MORNING...ESPECIALLY AT KCHS.
&&
.MARINE...
EARLY MORNING UPDATE...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR
THE CHARLESTON HARBOR AND THE CHARLESTON COUNTY WATERS. THE
CHARLESTON HARBOR PILOT BOAT REPORTED NEAR ZERO VISIBILITY
RECENTLY AND WEB CAMS AROUND DOWNTOWN AND THE HARBOR SHOW A
SHALLOW BANK OF FOG ACROSS THE AREA. THE EXPECTATION IS THAT THERE
IS ALSO DENSE FOG JUST OFFSHORE TOO...THUS THE ADVISORY IS IN
EFFECT. THE FOG SHOULD START TO MIX OUT AND DISSIPATE IN THE LATE
MORNING HOURS/AROUND NOON AS THE COLD FRONT MOVES IN...WINDS PICK
UP AND SHIFT AROUND TO NORTH.
TODAY AND TONIGHT...A COLD FRONT WILL SINK SOUTHWARD
ACROSS THE REGION AND IS EXPECTED TO PUSH ACROSS THE WATERS MAINLY
IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...A SIGNIFICANT
NORTH TO NORTHEAST SURGE IS EXPECTED TO BEGIN WITH RAPIDLY
INCREASING WINDS AND SEAS. WINDS WILL INCREASE FIRST ACROSS THE
CHARLESTON COUNTY WATERS AND THE CHARLESTON HARBOR IN THE EARLY
AFTERNOON...REACHING THE GEORGIA WATERS IN THE LATE AFTERNOON AND
EARLY EVENING HOURS. THE NEARSHORE WATERS WILL SEE WINDS INCREASE
INTO THE 20 TO 25 KT RANGE...INCLUDING THE CHARLESTON HARBOR...WITH
GUSTS TO 30 KT POSSIBLE FOR THE OUTER GEORGIA WATERS. SMALL CRAFT
ADVISORIES ARE IN EFFECT FOR ALL WATERS THROUGH THE OVERNIGHT. THE
NORTH TO NORTHEAST SURGE WILL CONTINUE TONIGHT IN THE WAKE OF THE
FRONT AS THE PRESSURE GRADIENT TIGHTENS ACROSS THE WATERS. WINDS
WILL LIKELY REACH THEIR PEAK IN THE MID TO LATE EVENING HOURS WITH
GUSTS TO 30 KT POSSIBLE ACROSS ALL WATERS. SEAS WILL CONTINUE TO
INCREASE REACHING 4-6 FT WITHIN 20 NM AND 6-9 FT OUT TO 60 NM.
TUESDAY...ONGOING SMALL CRAFT ADVISORIES WILL CONTINUE INTO THE
AFTERNOON IN ASSOCIATION WITH THE GRADIENT BETWEEN THE ATLANTIC LOW
AND A WEAK INLAND HIGH PRESSURE WEDGE. WHILE WE CAN/T RULE OUT A
LITTLE FREEZING RAIN IN CHARLESTON HARBOR...THE BULK OF THE WET
WEATHER LOOKS TO BE IN THE FORM OF LIQUID.
TUESDAY NIGHT INTO WEDNESDAY...CONDITIONS WILL IMPROVE AS THE
ATLANTIC LOW PULLS AWAY AND ANOTHER AREA OF HIGH PRESSURE ARRIVES
FROM THE WEST. WINDS AND SEAS WILL BE FAR BELOW ANY ADVISORY
THRESHOLDS.
LATE WEDNESDAY INTO THURSDAY...CONDITIONS AGAIN WILL DETERIORATE AS
INTENSIFYING LOW PRESSURE DEVELOPS IN THE GULF OF MEXICO AND TRACKS
OVER OR NEAR THE LOCAL WATERS LATE WEDNESDAY NIGHT/EARLY
THURSDAY...BEFORE PULLING AWAY THURSDAY AFTERNOON. SMALL CRAFT
ADVISORIES ARE AGAIN LIKELY AS A RESULT.
FRIDAY THROUGH SATURDAY...A STRENGTHENING REGION OF CONTINENTAL HIGH
PRESSURE WILL OVERSPREAD THE REGION AND GIVEN COLD ADVECTION AND A
TIGHTENING OF THE PRESSURE GRADIENT ADDITIONAL SMALL CRAFT
ADVISORIES ARE ANTICIPATED.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR
GAZ087-088.
SC...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR
SCZ040-042>045-047>050-052.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST
TUESDAY FOR AMZ352.
DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR AMZ330-350.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 5 PM EST
TUESDAY FOR AMZ350.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 PM EST
TUESDAY FOR AMZ354.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 10 PM EST
TUESDAY FOR AMZ374.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 2 PM EST
TUESDAY FOR AMZ330.
&&
$$
SYNOPSIS...
NEAR TERM...BSH
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...BSH
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
548 AM EST MON FEB 23 2015
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE REGION TODAY AND BECOME STATIONARY
SOUTH OF THE AREA TONIGHT. DEVELOPING LOW PRESSURE WILL TRACK ALONG
THE STATIONARY FRONT OVER THE ATLANTIC TUESDAY. HIGH PRESSURE WILL
BRIEFLY BUILD IN TUESDAY NIGHT INTO EARLY WEDNESDAY...FOLLOWED BY
STRONGER LOW PRESSURE FROM THE GULF OF MEXICO THAT PASSES OFFSHORE
WEDNESDAY NIGHT. STRONG HIGH PRESSURE CENTERED NORTH OF THE AREA
WILL EXPAND TO BECOME THE PRIMARY FEATURE LATE WEEK INTO NEXT
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
TODAY...SHORTWAVE ENERGY EMBEDDED WITHIN THE NEARLY ZONAL FLOW ALOFT
IS HELPING PROVIDE SOME UPPER SUPPORT FOR LOW LEVEL FORCING ALONG A
COLD FRONT THAT STRETCHES FROM EASTERN NORTH CAROLINA BACK TO THE
LOWER MISSISSIPPI VALLEY. THE RESULT IS A LARGE BAND OF WIDESPREAD
RAINFALL THAT IS IMPACTING MUCH OF THE NORTHERN HALF OF THE FORECAST
AREA THIS MORNING. POPS THROUGH THE REMAINDER OF THE MORNING FEATURE
100 POPS TO THE NORTH...RANGING TO SLIGHT CHANCES FAR TO THE SOUTH
AROUND MCINTOSH COUNTY. THE BEST FORCING WILL REMAIN FOCUSED TO THE
NORTH AND THAT IS WHERE THE HEAVIEST RAIN WILL FALL. THEN FOLLOWING
THE RECENT RUNS OF THE HRRR AND THE RAP...THE BULK OF THE
PRECIPITATION WILL COME TO AN END FROM WEST TO EAST IN THE LATE
MORNING TO EARLY AFTERNOON HOURS. TEMPERATURES ARE CURRENTLY QUITE
MILD ACROSS THE REGION...MAINLY IN THE UPPER 50S AND LOW 60S. THESE
VALUES WILL REMAIN STEADY THROUGH DAYBREAK...AND ONLY BEGIN TO FALL
WITH THE SOUTHWARD PROGRESSION OF THE COLD FRONT. BASED ON THE
TIMING IN THE HRRR AND RAP...THE WIND SHIFT AND ASSOCIATED
INFILTRATION OF COOLER AIR WILL BEGIN TAKING PLACE AROUND 13Z OR SO.
HIGH TEMPERATURES FOR THE DAY WILL OCCUR JUST BEFORE THE FRONT
BEGINS ITS SOUTHWARD MARCH...WITH MID 50S IN MOST AREAS AND EVEN
SOME UPPER 50S AND LOW 60S POSSIBLE FOR SOUTHEAST GEORGIA.
TEMPERATURES WILL THEN STEADILY FALL THROUGH THE DAY.
TONIGHT...THE COLD FRONT WILL BECOME NEARLY STATIONARY TO THE SOUTH
AND SOUTHEAST OF THE REGION AS HIGH PRESSURE BEGINS TO BRIDGE ACROSS
THE OHIO VALLEY AND INTO THE MID ATLANTIC. BY LATE TONIGHT...THE
HIGH WILL SETTLE INTO COLD AIR DAMMING POSITION WITH INCREASINGLY
COOL AIR OOZING IN FROM THE NORTHEAST. EARLY IN THE TONIGHT
PERIOD...THE MODELS GENERALLY SHOW A PRECIPITATION LULL PERIOD AS
THE FORCING ALONG THE FRONT IS DISPLACED TO THE SOUTH AND SOUTHEAST
AND THE UPPER SUPPORT WANES. HOWEVER...BY VERY LATE TONIGHT THE NOSE
OF A 80-90 KT 500 MB JET PUSHES IN FROM THE EAST COINCIDENT WITH AN
AREA OF SHALLOW LOW LEVEL ISENTROPIC LIFT. SOME OF THE MODELS SHOW
PRECIPITATION BREAKING OUT CLOSER TO SUNRISE AT THE SAME TIME AS SUB
FREEZING AIR FILTERS IN FROM THE NORTHEAST. SOUNDINGS SHOW THAT
WHATEVER PRECIPITATION DOES FALL WILL LIKELY FALL AS FREEZING
RAIN/DRIZZLE AND THROUGH THE VERY LATE TONIGHT PERIOD WILL MAINLY
IMPACT THE EXTREME NORTH...ALONG AND NEAR THE SANTEE RIVER. THE BULK
OF THIS EVENT WILL THEN OCCUR INTO TUESDAY MORNING. BY LATE
TONIGHT...LOWS WILL REACH THE LOW 30S FOR MUCH OF SOUTHEAST SOUTH
CAROLINA WITH MID TO UPPER 30S IN SOUTHEAST GEORGIA.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
TUESDAY...THE STALLED OUT FRONT AND ITS ASSOCIATED BAROCLINIC ZONE
WILL BE FOUND NOT FAR OFF THE SE COAST. CHANNELED VORTICITY ARRIVING
IN THE FAST MOVING AND BROADLY CYCLONIC FLOW ALOFT WILL TRIGGER
CYCLOGENESIS A COUPLE HUNDRED MILES OFF THE NE FLORIDA COAST. AT THE
SAME TIME...UPPER DIVERGENCE/DIFLUENCE ASSOCIATED WITH THE EXIT
REGION OF A ROBUST 130 KT JET AND ISENTROPIC ASCENT ON MAINLY THE
280K AND 285K SURFACES /AROUND 1500-2500 FT/ WILL COMBINE WITH
PRODUCE AN EXPANDING AREA OF RAIN ACROSS THE FORECAST AREA. THERE
STILL REMAINS SOME DISPARITIES BETWEEN THE VARIOUS MODEL
GUIDANCE...BUT WE HAVE LEANED TOWARD A SOLUTION MOST SIMILAR TO A
BLEND OF THE NAM...ECMWF AND CANADIAN MODELS AS OPPOSED TO THE GFS.
COLDER AIR WILL BE FILTERING INTO THE REGION AS A TRANSIENT HIGH
PRESSURE WEDGE DEVELOPS BEHIND THE COLD FRONT STALLED OFFSHORE. THIS
WILL CAUSE A CONCERN FOR THE POTENTIAL FOR FREEZING RAIN AND DRIZZLE
OVER SEVERAL PARTS OF THE FORECAST AREA. SOUNDING DATA REVEALS THAT
THE BEST CHANCE FOR FREEZING SURFACE TEMPS AND/OR WET BULBS WILL
OCCUR MAINLY INLAND FROM US-17 IN SC AND OVER JENKINS AND SCREVEN
COUNTIES IN SE GA. THIS INCLUDES PARTS OF THE CHARLESTON AND
BEAUFORT METRO AREAS...AND IT IS IN THESE LOCATIONS WHERE WE HAVE
GONE AHEAD WITH A FREEZING RAIN ADVISORY FROM 4 AM UNTIL 2 PM
TUESDAY. WHILE IT IS CERTAINLY COLD ENOUGH FOR ICE/SNOW
ALOFT...THERE IS A PRONOUNCED WARM NOSE AROUND 900-750 MB WHICH WILL
TURN WILL ALLOW FOR MELTING OF THE FROZEN PRECIP. BUT THERE IS
ENOUGH MOISTURE AND COLDER AIR BELOW TO ALLOW FOR THE LIQUID DROPS
TO REFREEZE. THERE CAN CERTAINLY BE SOME SLEET MIXED IN...BUT THE
BULK OF THE PRECIP LOOKS TO BE FREEZING RAIN AND/OR DRIZZLE. OUR
CONFIDENCE ON THE AMOUNT OF ICING IS MODERATE AT BEST...SINCE WE
HAVE HAD A SHORT DURATION WARM SPELL AND MUCH OF THE PRECIP MAY TURN
OUT BE RATHER LIGHT IN INTENSITY. THAT SAID...WE DO ANTICIPATE A FEW
HUNDREDTHS OF AN INCH OF FREEZING RAIN ON VARIOUS SURFACES. KEEP IN
MIND THAT THE TALLER BRIDGES OF THE AREA CAN FREEZE BEFORE ROAD
SURFACES. THE DON HOLT BRIDGE IN THE CHARLESTON AREA PROBABLY HAS
THE BEST CHANCE OF EXPERIENCING ANY ICING PROBLEMS TUESDAY
MORNING...BUT WE CAN/T ENTIRELY DISCOUNT THE RAVENEL AND WANDO
BRIDGES ALSO GETTING SOME ICE ON THEM. DEPENDING UPON THE INTENSITY
OF THE PRECIP WE MAY NEED TO EXPAND THE ADVISORY A LITTLE FURTHER
SOUTH INTO GEORGIA AT A LATER TIME. TEMPS LOOK TO BE ABOVE FREEZING
IN THE EARLY TO MID AFTERNOON...THUS ANY FREEZING PRECIP WILL CHANGE
OVER TO LIQUID BEFORE TAPERING OFF LATE.
FOR NOW WE BELIEVE THAT THE PRECIP OVER MUCH OF SE GA...ESPECIALLY
TO THE SOUTH OF I-16 WILL BE ALL OR MAINLY LIQUID WITH QPF/S OF 1/10
TO 1/4 INCH TO OCCUR. TEMPS WON/T GO MUCH OF ANYWHERE...EVEN
DROPPING A COUPLE OF DEGREES DUE TO THE PRECIP...AND WE/LL BE MAINLY
IN THE LOWER AND MIDDLE 30S NORTH/NW TO THE LOWER 40S SOUTH.
TUESDAY NIGHT...THE SURFACE WAVE OVER THE ATLANTIC AND THE
ASSOCIATED FORCING PULL AWAY AS A MESO-HIGH BUILDS FROM THE WEST.
THIS WILL TEMPORARILY SHUT OFF THE PRECIP...AND WE WILL NEED TO
WATCH FOR POSSIBLE RE-FREEZING OF THE EARLIER RAINS...ESPECIALLY OVER
THE CHARLESTON QUAD-COUNTY DISTRICT.
WEDNESDAY AND WEDNESDAY NIGHT...A POTENT SHORT WAVE IN THE DESERT SW
TODAY WILL SHIFT THROUGH THE SOUTHERN PLAINS WEDNESDAY AND HEADS
INTO THE SE AT NIGHT. THIS TRIGGERS SURFACE CYCLOGENESIS IN THE
NORTHERN GULF OF MEXICO BEFORE THE LOW TRACKS JUST OFF THE LOCAL
COASTS BY LATE IN THE PERIOD. LARGE SCALE FORCING FROM THESE
FEATURES AND A POWERFUL WEST-EAST 150 KT UPPER JET WILL ALLOW FOR
CONSIDERABLE OVER-RUNNING RAINS TO DEVELOP BY WEDNESDAY
AFTERNOON...BEFORE TAPERING OFF FROM WEST/SW TO EAST/NE LATE
WEDNESDAY NIGHT. THIS PROMISES TO BE A PRETTY GOOD SOAKER...WITH
PWATS OF 1-1.5 INCHES TO PREVAIL. SOME PLACES COULD EASILY ACHIEVE
THESE AMOUNTS GIVEN THAT WE ARE CARRYING CATEGORICAL POPS. RIGHT
NOW IT LOOKS TO BE ALL LIQUID UNLESS THE OVER-RUNNING RAINS ARRIVE
EARLIER THAN EXPECTED. TEMPS WILL REMAIN FAR BELOW NORMAL.
THURSDAY...MUCH DRIER AIR OVERSPREADS THE REGION BEHIND THE EXITING
SHORT AVE AND SURFACE LOW...LEADING TO A DRY BUT CHILLY DAY WITH
TEMPS AGAIN FAR BELOW SEASONAL NORMS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
A HUMONGOUS AND ROBUST 1040 MB CANADIAN HIGH BUILDING OUT OF THE
GREAT PLAINS WILL EXPAND EAST AND SOUTH AND COVERS MUCH OF THE
NATION EAST OF THE ROCKIES...INCLUDING THE LOCAL AREA. THIS LEADS TO
DRY AND CHILLY CONDITIONS INTO FRIDAY...BEFORE THE HIGH SHIFTS INTO
THE ATLANTIC OVER THE WEEKEND AND EARLY NEXT WEEK AND TEMPS BEGIN TO
MODERATE. A COASTAL TROUGH WILL LIKELY FORM DURING THIS TRANSITION
JUST OFF OUR COAST...AND WE LOOK FOR AT LEAST A SMALL CHANCE OF
SHOWERS IN RESPONSE.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
ONGOING VFR CONDITIONS AT KCHS AND KSAV WILL ONLY LAST A FEW MORE
HOURS AS RAINFALL AND LOWERING CEILINGS BEGIN TO IMPACT THE
TERMINALS. AT KCHS...RAINFALL WILL BECOME STEADY AND PERIODICALLY
MODERATE IN INTENSITY. CEILINGS ARE EXPECTED TO FALL TO MVFR BY
08Z...THOUGH VISIBILITIES IN RAIN COULD BE MVFR OR TEMPORARILY IFR
AT TIMES. CEILINGS WILL CONTINUE TO STEADILY FALL AND REACH IFR
LEVELS AROUND 10Z. THE PRECIPITATION WILL COME TO AN END AROUND
16Z AND THEN LITTLE TO NO RAIN IS EXPECTED THROUGH THE END OF THE
FORECAST. IFR CEILINGS WILL STICK THROUGH THE DAY...LIFTING TO
MVFR IN THE LATE EVENING HOURS. THE MAIN WIND SHIFT WITH THE FRONT
WILL TAKE PLACE AROUND NOON AND WINDS THEREAFTER WILL INCREASE AND
BECOME NORTHERLY. AT KSAV...RAINFALL CHANCES ARE MUCH LOWER AND
THE OVERALL TIMING OF LOWERING CEILINGS WILL BE ABOUT 2-3 HOURS
LATER THAN KCHS. SIMILARLY...IFR CEILINGS WILL SETTLE IN BY LATE
MORNING AND REMAIN THROUGH THE DAY. THE WIND SHIFT WITH THE FRONT
WILL ARRIVE AT KSAV IN THE EARLY AFTERNOON. AN IMPROVEMENT TO MVFR
SHOULD TAKE PLACE CLOSER TO MIDNIGHT.
EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS OF VARYING
CATEGORIES WILL CONTINUE MUCH OF THE TIME MONDAY NIGHT INTO
THURSDAY...ALTHOUGH INTERLUDES OF VFR ARE POSSIBLE BETWEEN RAIN
EVENTS. ALSO OF NOTE...THERE IS A SLIGHT CHANCE FOR FREEZING/FROZEN
PRECIPITATION LATE MONDAY NIGHT INTO TUESDAY MORNING.
&&
.MARINE...
EARLY MORNING UPDATE...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR
THE CHARLESTON HARBOR AND THE CHARLESTON COUNTY WATERS. THE
CHARLESTON HARBOR PILOT BOAT REPORTED NEAR ZERO VISIBILITY
RECENTLY AND WEB CAMS AROUND DOWNTOWN AND THE HARBOR SHOW A
SHALLOW BANK OF FOG ACROSS THE AREA. THE EXPECTATION IS THAT THERE
IS ALSO DENSE FOG JUST OFFSHORE TOO...THUS THE ADVISORY IS IN
EFFECT. THE FOG SHOULD START TO MIX OUT AND DISSIPATE IN THE LATE
MORNING HOURS/AROUND NOON AS THE COLD FRONT MOVES IN...WINDS PICK
UP AND SHIFT AROUND TO NORTH.
TODAY AND TONIGHT...A COLD FRONT WILL SINK SOUTHWARD
ACROSS THE REGION AND IS EXPECTED TO PUSH ACROSS THE WATERS MAINLY
IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...A SIGNIFICANT
NORTH TO NORTHEAST SURGE IS EXPECTED TO BEGIN WITH RAPIDLY
INCREASING WINDS AND SEAS. WINDS WILL INCREASE FIRST ACROSS THE
CHARLESTON COUNTY WATERS AND THE CHARLESTON HARBOR IN THE EARLY
AFTERNOON...REACHING THE GEORGIA WATERS IN THE LATE AFTERNOON AND
EARLY EVENING HOURS. THE NEARSHORE WATERS WILL SEE WINDS INCREASE
INTO THE 20 TO 25 KT RANGE...INCLUDING THE CHARLESTON HARBOR...WITH
GUSTS TO 30 KT POSSIBLE FOR THE OUTER GEORGIA WATERS. SMALL CRAFT
ADVISORIES ARE IN EFFECT FOR ALL WATERS THROUGH THE OVERNIGHT. THE
NORTH TO NORTHEAST SURGE WILL CONTINUE TONIGHT IN THE WAKE OF THE
FRONT AS THE PRESSURE GRADIENT TIGHTENS ACROSS THE WATERS. WINDS
WILL LIKELY REACH THEIR PEAK IN THE MID TO LATE EVENING HOURS WITH
GUSTS TO 30 KT POSSIBLE ACROSS ALL WATERS. SEAS WILL CONTINUE TO
INCREASE REACHING 4-6 FT WITHIN 20 NM AND 6-9 FT OUT TO 60 NM.
TUESDAY...ONGOING SMALL CRAFT ADVISORIES WILL CONTINUE INTO THE
AFTERNOON IN ASSOCIATION WITH THE GRADIENT BETWEEN THE ATLANTIC LOW
AND A WEAK INLAND HIGH PRESSURE WEDGE. WHILE WE CAN/T RULE OUT A
LITTLE FREEZING RAIN IN CHARLESTON HARBOR...THE BULK OF THE WET
WEATHER LOOKS TO BE IN THE FORM OF LIQUID.
TUESDAY NIGHT INTO WEDNESDAY...CONDITIONS WILL IMPROVE AS THE
ATLANTIC LOW PULLS AWAY AND ANOTHER AREA OF HIGH PRESSURE ARRIVES
FROM THE WEST. WINDS AND SEAS WILL BE FAR BELOW ANY ADVISORY
THRESHOLDS.
LATE WEDNESDAY INTO THURSDAY...CONDITIONS AGAIN WILL DETERIORATE AS
INTENSIFYING LOW PRESSURE DEVELOPS IN THE GULF OF MEXICO AND TRACKS
OVER OR NEAR THE LOCAL WATERS LATE WEDNESDAY NIGHT/EARLY
THURSDAY...BEFORE PULLING AWAY THURSDAY AFTERNOON. SMALL CRAFT
ADVISORIES ARE AGAIN LIKELY AS A RESULT.
FRIDAY THROUGH SATURDAY...A STRENGTHENING REGION OF CONTINENTAL HIGH
PRESSURE WILL OVERSPREAD THE REGION AND GIVEN COLD ADVECTION AND A
TIGHTENING OF THE PRESSURE GRADIENT ADDITIONAL SMALL CRAFT
ADVISORIES ARE ANTICIPATED.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR
GAZ087-088.
SC...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR
SCZ040-042>045-047>050-052.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST
TUESDAY FOR AMZ352.
DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR AMZ330-350.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 5 PM EST
TUESDAY FOR AMZ350.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 PM EST
TUESDAY FOR AMZ354.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 10 PM EST
TUESDAY FOR AMZ374.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 2 PM EST
TUESDAY FOR AMZ330.
&&
$$
NEAR TERM...BSH
SHORT TERM...
LONG TERM...
AVIATION...BSH
MARINE...BSH
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
419 AM EST MON FEB 23 2015
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE REGION TODAY AND BECOME STATIONARY
SOUTH OF THE AREA TONIGHT. DEVELOPING LOW PRESSURE WILL TRACK ALONG
THE STATIONARY FRONT OVER THE ATLANTIC TUESDAY. HIGH PRESSURE WILL
BRIEFLY BUILD IN TUESDAY NIGHT INTO EARLY WEDNESDAY...FOLLOWED BY
STRONGER LOW PRESSURE FROM THE GULF OF MEXICO THAT PASSES OFFSHORE
WEDNESDAY NIGHT. STRONG HIGH PRESSURE CENTERED NORTH OF THE AREA
WILL EXPAND TO BECOME THE PRIMARY FEATURE LATE WEEK INTO NEXT
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
TODAY...SHORTWAVE ENERGY EMBEDDED WITHIN THE NEARLY ZONAL FLOW ALOFT
IS HELPING PROVIDE SOME UPPER SUPPORT FOR LOW LEVEL FORCING ALONG A
COLD FRONT THAT STRETCHES FROM EASTERN NORTH CAROLINA BACK TO THE
LOWER MISSISSIPPI VALLEY. THE RESULT IS A LARGE BAND OF WIDESPREAD
RAINFALL THAT IS IMPACTING MUCH OF THE NORTHERN HALF OF THE FORECAST
AREA THIS MORNING. POPS THROUGH THE REMAINDER OF THE MORNING FEATURE
100 POPS TO THE NORTH...RANGING TO SLIGHT CHANCES FAR TO THE SOUTH
AROUND MCINTOSH COUNTY. THE BEST FORCING WILL REMAIN FOCUSED TO THE
NORTH AND THAT IS WHERE THE HEAVIEST RAIN WILL FALL. THEN FOLLOWING
THE RECENT RUNS OF THE HRRR AND THE RAP...THE BULK OF THE
PRECIPITATION WILL COME TO AN END FROM WEST TO EAST IN THE LATE
MORNING TO EARLY AFTERNOON HOURS. TEMPERATURES ARE CURRENTLY QUITE
MILD ACROSS THE REGION...MAINLY IN THE UPPER 50S AND LOW 60S. THESE
VALUES WILL REMAIN STEADY THROUGH DAYBREAK...AND ONLY BEGIN TO FALL
WITH THE SOUTHWARD PROGRESSION OF THE COLD FRONT. BASED ON THE
TIMING IN THE HRRR AND RAP...THE WIND SHIFT AND ASSOCIATED
INFILTRATION OF COOLER AIR WILL BEGIN TAKING PLACE AROUND 13Z OR SO.
HIGH TEMPERATURES FOR THE DAY WILL OCCUR JUST BEFORE THE FRONT
BEGINS ITS SOUTHWARD MARCH...WITH MID 50S IN MOST AREAS AND EVEN
SOME UPPER 50S AND LOW 60S POSSIBLE FOR SOUTHEAST GEORGIA.
TEMPERATURES WILL THEN STEADILY FALL THROUGH THE DAY.
TONIGHT...THE COLD FRONT WILL BECOME NEARLY STATIONARY TO THE SOUTH
AND SOUTHEAST OF THE REGION AS HIGH PRESSURE BEGINS TO BRIDGE ACROSS
THE OHIO VALLEY AND INTO THE MID ATLANTIC. BY LATE TONIGHT...THE
HIGH WILL SETTLE INTO COLD AIR DAMMING POSITION WITH INCREASINGLY
COOL AIR OOZING IN FROM THE NORTHEAST. EARLY IN THE TONIGHT
PERIOD...THE MODELS GENERALLY SHOW A PRECIPITATION LULL PERIOD AS
THE FORCING ALONG THE FRONT IS DISPLACED TO THE SOUTH AND SOUTHEAST
AND THE UPPER SUPPORT WANES. HOWEVER...BY VERY LATE TONIGHT THE NOSE
OF A 80-90 KT 500 MB JET PUSHES IN FROM THE EAST COINCIDENT WITH AN
AREA OF SHALLOW LOW LEVEL ISENTROPIC LIFT. SOME OF THE MODELS SHOW
PRECIPITATION BREAKING OUT CLOSER TO SUNRISE AT THE SAME TIME AS SUB
FREEZING AIR FILTERS IN FROM THE NORTHEAST. SOUNDINGS SHOW THAT
WHATEVER PRECIPITATION DOES FALL WILL LIKELY FALL AS FREEZING
RAIN/DRIZZLE AND THROUGH THE VERY LATE TONIGHT PERIOD WILL MAINLY
IMPACT THE EXTREME NORTH...ALONG AND NEAR THE SANTEE RIVER. THE BULK
OF THIS EVENT WILL THEN OCCUR INTO TUESDAY MORNING. BY LATE
TONIGHT...LOWS WILL REACH THE LOW 30S FOR MUCH OF SOUTHEAST SOUTH
CAROLINA WITH MID TO UPPER 30S IN SOUTHEAST GEORGIA.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
TUESDAY...THE STALLED OUT FRONT AND ITS ASSOCIATED BAROCLINIC ZONE
WILL BE FOUND NOT FAR OFF THE SE COAST. CHANNELED VORTICITY ARRIVING
IN THE FAST MOVING AND BROADLY CYCLONIC FLOW ALOFT WILL TRIGGER
CYCLOGENESIS A COUPLE HUNDRED MILES OFF THE NE FLORIDA COAST. AT THE
SAME TIME...UPPER DIVERGENCE/DIFLUENCE ASSOCIATED WITH THE EXIT
REGION OF A ROBUST 130 KT JET AND ISENTROPIC ASCENT ON MAINLY THE
280K AND 285K SURFACES /AROUND 1500-2500 FT/ WILL COMBINE WITH
PRODUCE AN EXPANDING AREA OF RAIN ACROSS THE FORECAST AREA. THERE
STILL REMAINS SOME DISPARITIES BETWEEN THE VARIOUS MODEL
GUIDANCE...BUT WE HAVE LEANED TOWARD A SOLUTION MOST SIMILAR TO A
BLEND OF THE NAM...ECMWF AND CANADIAN MODELS AS OPPOSED TO THE GFS.
COLDER AIR WILL BE FILTERING INTO THE REGION AS A TRANSIENT HIGH
PRESSURE WEDGE DEVELOPS BEHIND THE COLD FRONT STALLED OFFSHORE. THIS
WILL CAUSE A CONCERN FOR THE POTENTIAL FOR FREEZING RAIN AND DRIZZLE
OVER SEVERAL PARTS OF THE FORECAST AREA. SOUNDING DATA REVEALS THAT
THE BEST CHANCE FOR FREEZING SURFACE TEMPS AND/OR WET BULBS WILL
OCCUR MAINLY INLAND FROM US-17 IN SC AND OVER JENKINS AND SCREVEN
COUNTIES IN SE GA. THIS INCLUDES PARTS OF THE CHARLESTON AND
BEAUFORT METRO AREAS...AND IT IS IN THESE LOCATIONS WHERE WE HAVE
GONE AHEAD WITH A FREEZING RAIN ADVISORY FROM 4 AM UNTIL 2 PM
TUESDAY. WHILE IT IS CERTAINLY COLD ENOUGH FOR ICE/SNOW
ALOFT...THERE IS A PRONOUNCED WARM NOSE AROUND 900-750 MB WHICH WILL
TURN WILL ALLOW FOR MELTING OF THE FROZEN PRECIP. BUT THERE IS
ENOUGH MOISTURE AND COLDER AIR BELOW TO ALLOW FOR THE LIQUID DROPS
TO REFREEZE. THERE CAN CERTAINLY BE SOME SLEET MIXED IN...BUT THE
BULK OF THE PRECIP LOOKS TO BE FREEZING RAIN AND/OR DRIZZLE. OUR
CONFIDENCE ON THE AMOUNT OF ICING IS MODERATE AT BEST...SINCE WE
HAVE HAD A SHORT DURATION WARM SPELL AND MUCH OF THE PRECIP MAY TURN
OUT BE RATHER LIGHT IN INTENSITY. THAT SAID...WE DO ANTICIPATE A FEW
HUNDREDTHS OF AN INCH OF FREEZING RAIN ON VARIOUS SURFACES. KEEP IN
MIND THAT THE TALLER BRIDGES OF THE AREA CAN FREEZE BEFORE ROAD
SURFACES. THE DON HOLT BRIDGE IN THE CHARLESTON AREA PROBABLY HAS
THE BEST CHANCE OF EXPERIENCING ANY ICING PROBLEMS TUESDAY
MORNING...BUT WE CAN/T ENTIRELY DISCOUNT THE RAVENEL AND WANDO
BRIDGES ALSO GETTING SOME ICE ON THEM. DEPENDING UPON THE INTENSITY
OF THE PRECIP WE MAY NEED TO EXPAND THE ADVISORY A LITTLE FURTHER
SOUTH INTO GEORGIA AT A LATER TIME. TEMPS LOOK TO BE ABOVE FREEZING
IN THE EARLY TO MID AFTERNOON...THUS ANY FREEZING PRECIP WILL CHANGE
OVER TO LIQUID BEFORE TAPERING OFF LATE.
FOR NOW WE BELIEVE THAT THE PRECIP OVER MUCH OF SE GA...ESPECIALLY
TO THE SOUTH OF I-16 WILL BE ALL OR MAINLY LIQUID WITH QPF/S OF 1/10
TO 1/4 INCH TO OCCUR. TEMPS WON/T GO MUCH OF ANYWHERE...EVEN
DROPPING A COUPLE OF DEGREES DUE TO THE PRECIP...AND WE/LL BE MAINLY
IN THE LOWER AND MIDDLE 30S NORTH/NW TO THE LOWER 40S SOUTH.
TUESDAY NIGHT...THE SURFACE WAVE OVER THE ATLANTIC AND THE
ASSOCIATED FORCING PULL AWAY AS A MESO-HIGH BUILDS FROM THE WEST.
THIS WILL TEMPORARILY SHUT OFF THE PRECIP...AND WE WILL NEED TO
WATCH FOR POSSIBLE RE-FREEZING OF THE EARLIER RAINS...ESPECIALLY OVER
THE CHARLESTON QUAD-COUNTY DISTRICT.
WEDNESDAY AND WEDNESDAY NIGHT...A POTENT SHORT WAVE IN THE DESERT SW
TODAY WILL SHIFT THROUGH THE SOUTHERN PLAINS WEDNESDAY AND HEADS
INTO THE SE AT NIGHT. THIS TRIGGERS SURFACE CYCLOGENESIS IN THE
NORTHERN GULF OF MEXICO BEFORE THE LOW TRACKS JUST OFF THE LOCAL
COASTS BY LATE IN THE PERIOD. LARGE SCALE FORCING FROM THESE
FEATURES AND A POWERFUL WEST-EAST 150 KT UPPER JET WILL ALLOW FOR
CONSIDERABLE OVER-RUNNING RAINS TO DEVELOP BY WEDNESDAY
AFTERNOON...BEFORE TAPERING OFF FROM WEST/SW TO EAST/NE LATE
WEDNESDAY NIGHT. THIS PROMISES TO BE A PRETTY GOOD SOAKER...WITH
PWATS OF 1-1.5 INCHES TO PREVAIL. SOME PLACES COULD EASILY ACHIEVE
THESE AMOUNTS GIVEN THAT WE ARE CARRYING CATEGORICAL POPS. RIGHT
NOW IT LOOKS TO BE ALL LIQUID UNLESS THE OVER-RUNNING RAINS ARRIVE
EARLIER THAN EXPECTED. TEMPS WILL REMAIN FAR BELOW NORMAL.
THURSDAY...MUCH DRIER AIR OVERSPREADS THE REGION BEHIND THE EXITING
SHORT AVE AND SURFACE LOW...LEADING TO A DRY BUT CHILLY DAY WITH
TEMPS AGAIN FAR BELOW SEASONAL NORMS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
A HUMONGOUS AND ROBUST 1040 MB CANADIAN HIGH BUILDING OUT OF THE
GREAT PLAINS WILL EXPAND EAST AND SOUTH AND COVERS MUCH OF THE
NATION EAST OF THE ROCKIES...INCLUDING THE LOCAL AREA. THIS LEADS TO
DRY AND CHILLY CONDITIONS INTO FRIDAY...BEFORE THE HIGH SHIFTS INTO
THE ATLANTIC OVER THE WEEKEND AND EARLY NEXT WEEK AND TEMPS BEGIN TO
MODERATE. A COASTAL TROUGH WILL LIKELY FORM DURING THIS TRANSITION
JUST OFF OUR COAST...AND WE LOOK FOR AT LEAST A SMALL CHANCE OF
SHOWERS IN RESPONSE.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
ONGOING VFR CONDITIONS AT KCHS AND KSAV WILL ONLY LAST A FEW MORE
HOURS AS RAINFALL AND LOWERING CEILINGS BEGIN TO IMPACT THE
TERMINALS. AT KCHS...RAINFALL WILL BECOME STEADY AND PERIODICALLY
MODERATE IN INTENSITY. CEILINGS ARE EXPECTED TO FALL TO MVFR BY
08Z...THOUGH VISIBILITIES IN RAIN COULD BE MVFR OR TEMPORARILY IFR
AT TIMES. CEILINGS WILL CONTINUE TO STEADILY FALL AND REACH IFR
LEVELS AROUND 10Z. THE PRECIPITATION WILL COME TO AN END AROUND
16Z AND THEN LITTLE TO NO RAIN IS EXPECTED THROUGH THE END OF THE
FORECAST. IFR CEILINGS WILL STICK THROUGH THE DAY...LIFTING TO
MVFR IN THE LATE EVENING HOURS. THE MAIN WIND SHIFT WITH THE FRONT
WILL TAKE PLACE AROUND NOON AND WINDS THEREAFTER WILL INCREASE AND
BECOME NORTHERLY. AT KSAV...RAINFALL CHANCES ARE MUCH LOWER AND
THE OVERALL TIMING OF LOWERING CEILINGS WILL BE ABOUT 2-3 HOURS
LATER THAN KCHS. SIMILARLY...IFR CEILINGS WILL SETTLE IN BY LATE
MORNING AND REMAIN THROUGH THE DAY. THE WIND SHIFT WITH THE FRONT
WILL ARRIVE AT KSAV IN THE EARLY AFTERNOON. AN IMPROVEMENT TO MVFR
SHOULD TAKE PLACE CLOSER TO MIDNIGHT.
EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS OF VARYING
CATEGORIES WILL CONTINUE MUCH OF THE TIME MONDAY NIGHT INTO
THURSDAY...ALTHOUGH INTERLUDES OF VFR ARE POSSIBLE BETWEEN RAIN
EVENTS. ALSO OF NOTE...THERE IS A SLIGHT CHANCE FOR FREEZING/FROZEN
PRECIPITATION LATE MONDAY NIGHT INTO TUESDAY MORNING.
&&
.MARINE...
TODAY AND TONIGHT...A COLD FRONT WILL SINK SOUTHWARD
ACROSS THE REGION AND IS EXPECTED TO PUSH ACROSS THE WATERS MAINLY
IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...A SIGNIFICANT
NORTH TO NORTHEAST SURGE IS EXPECTED TO BEGIN WITH RAPIDLY
INCREASING WINDS AND SEAS. WINDS WILL INCREASE FIRST ACROSS THE
CHARLESTON COUNTY WATERS AND THE CHARLESTON HARBOR IN THE EARLY
AFTERNOON...REACHING THE GEORGIA WATERS IN THE LATE AFTERNOON AND
EARLY EVENING HOURS. THE NEARSHORE WATERS WILL SEE WINDS INCREASE
INTO THE 20 TO 25 KT RANGE...INCLUDING THE CHARLESTON HARBOR...WITH
GUSTS TO 30 KT POSSIBLE FOR THE OUTER GEORGIA WATERS. SMALL CRAFT
ADVISORIES ARE IN EFFECT FOR ALL WATERS THROUGH THE OVERNIGHT. THE
NORTH TO NORTHEAST SURGE WILL CONTINUE TONIGHT IN THE WAKE OF THE
FRONT AS THE PRESSURE GRADIENT TIGHTENS ACROSS THE WATERS. WINDS
WILL LIKELY REACH THEIR PEAK IN THE MID TO LATE EVENING HOURS WITH
GUSTS TO 30 KT POSSIBLE ACROSS ALL WATERS. SEAS WILL CONTINUE TO
INCREASE REACHING 4-6 FT WITHIN 20 NM AND 6-9 FT OUT TO 60 NM.
TUESDAY...ONGOING SMALL CRAFT ADVISORIES WILL CONTINUE INTO THE
AFTERNOON IN ASSOCIATION WITH THE GRADIENT BETWEEN THE ATLANTIC LOW
AND A WEAK INLAND HIGH PRESSURE WEDGE. WHILE WE CAN/T RULE OUT A
LITTLE FREEZING RAIN IN CHARLESTON HARBOR...THE BULK OF THE WET
WEATHER LOOKS TO BE IN THE FORM OF LIQUID.
TUESDAY NIGHT INTO WEDNESDAY...CONDITIONS WILL IMPROVE AS THE
ATLANTIC LOW PULLS AWAY AND ANOTHER AREA OF HIGH PRESSURE ARRIVES
FROM THE WEST. WINDS AND SEAS WILL BE FAR BELOW ANY ADVISORY
THRESHOLDS.
LATE WEDNESDAY INTO THURSDAY...CONDITIONS AGAIN WILL DETERIORATE AS
INTENSIFYING LOW PRESSURE DEVELOPS IN THE GULF OF MEXICO AND TRACKS
OVER OR NEAR THE LOCAL WATERS LATE WEDNESDAY NIGHT/EARLY
THURSDAY...BEFORE PULLING AWAY THURSDAY AFTERNOON. SMALL CRAFT
ADVISORIES ARE AGAIN LIKELY AS A RESULT.
FRIDAY THROUGH SATURDAY...A STRENGTHENING REGION OF CONTINENTAL HIGH
PRESSURE WILL OVERSPREAD THE REGION AND GIVEN COLD ADVECTION AND A
TIGHTENING OF THE PRESSURE GRADIENT ADDITIONAL SMALL CRAFT
ADVISORIES ARE ANTICIPATED.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR
GAZ087-088.
SC...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR
SCZ040-042>045-047>050-052.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST
TUESDAY FOR AMZ352.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 5 PM EST
TUESDAY FOR AMZ350.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 PM EST
TUESDAY FOR AMZ354.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 10 PM EST
TUESDAY FOR AMZ374.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 2 PM EST
TUESDAY FOR AMZ330.
&&
$$
NEAR TERM...BSH
SHORT TERM...
LONG TERM...
AVIATION...BSH
MARINE...BSH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1201 AM CST MON FEB 23 2015
.UPDATE...
757 PM CST
MADE A COUPLE TWEAKS TO GOING FORECAST`S TEMPERATURES...MAINLY TO
RAISE LOW TEMPS A BIT TONIGHT...ESPECIALLY IN THE URBAN HEAT
ISLAND AND ALSO NUDGED HIGHS UP A BIT MONDAY AS WELL. COLD ARCTIC
AIR CONTINUES TO SLOWLY FILTER INTO THE AREA...BUT GRADIENT IS
REMAINING TIGHT ENOUGH TO KEEP A BIT OF WIND BLOWING WHICH IS
PREVENTING TEMPS FROM TANKING DESPITE THE CLEAR SKY. THE TYPICALLY
COLDER AND MORE SHELTERED AREAS LIKE FOX AND ROCK RIVER VALLEYS
WILL LIKELY SEE WINDS DECOUPLE A BIT MORE THAN OTHER AREAS WITH
TEMPS DROPPING TO AROUND 10 BELOW THERE...BUT DOWNTOWN CHICAGO
WILL PROBABLY ONLY DROP TO AROUND ZERO. THE MINOR ADJUSTMENTS TO
TEMPERATURES AND WINDS SUGGEST THAT MOST AREAS WILL FALL SHORT OF
REACHING WIND CHILL ADVISORY CRITERIA...WITH MOST LIKELY AREAS TO
REACH IT BEING NORTH CENTRAL ILLINOIS INTO THE FAR WESTERN
CHICAGO SUBURBS...WITH WIND CHILLS ELSEWHERE LIKELY "ONLY"
DROPPING TO 15-20 BELOW. ITS POSSIBLE THAT MIDNIGHT SHIFT COULD
KILL WIND CHILL ADVISORY EARLY...BUT JUST NOT COMFORTABLE MAKING
CHANGES TO THE HEADLINE AT THIS TIME.
IZZI
&&
.SHORT TERM...
234 PM CST
TONIGHT THROUGH WEDNESDAY...
COLD TEMPERATURES AND DANGEROUSLY LOW WIND CHILLS TONIGHT AND EARLY
MONDAY ARE THE IMMEDIATE FORECAST CONCERNS IN THE SHORT TERM. WIND
CHILL ADVISORY REMAINS IN EFFECT FOR ENTIRE CWA FROM MIDNIGHT
TONIGHT THROUGH 10 AM CST MONDAY MORNING. COULD EVEN APPROACH
ROCKFORDS RECORD LOW OF -12 F.
1047 MB HIGH PRESSURE CENTERED OVER THE NORTHERN PLAINS THIS
AFTERNOON WILL CONTINUE TO SPREAD SOUTHEAST TO THE MID-MISSISSIPPI
VALLEY TONIGHT. ARCTIC AIR...VERY DRY AIR MASS AND CLEAR SKIES...
AND SLOWLY DIMINISHING WINDS WILL COMBINE TO PRODUCE BITTER COLD
SUB-ZERO TEMPERATURES ACROSS THE FORECAST AREA OVERNIGHT. WITH LOW
TEMPS REACHING FROM -2 TO -14 ACROSS THE CWA AND WINDS JUST UNDER 10
MPH BY MORNING...WIND CHILLS RANGING FROM NEAR 20 BELOW TO NEARLY 30
BELOW ARE EXPECTED BY SUNRISE MONDAY. THUS WIND CHILL ADVISORY
REMAINS IN EFFECT FOR ALL COUNTIES WITH NO CHANGES.
ON MONDAY...THE SURFACE HIGH AND EASTERN PORTION OF THE RIDGE AXIS
WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE AREA IN THE MORNING
BEFORE BECOMING ELONGATED ACROSS THE OHIO VALLEY LATE IN THE DAY.
COLD MORNING MINS AND SHALLOW MIXING IN THE VICINITY OF THE RIDGE
WILL LIKELY KEEP DAYTIME TEMPS IN THE SINGLE DIGITS TO NEAR 10
DEGREES IN MOST AREAS...DESPITE WINDS BECOMING WEST-SOUTHWEST AND
STARTING TO INCREASE DURING THE AFTERNOON. THIS WILL LIKELY RESULT
IN A RECORD LOW-MAX TEMP FOR THE ROCKFORD AREA MONDAY...AS THE
CURRENT RECORD LOW-MAX FOR RFD 2/23 IS A FAIRLY MILD 17 DEGREES.
WIND CHILLS WILL REMAIN SUB-ZERO THROUGH THE DAY...DESPITE MOSTLY
SUNNY SKIES.
ATTENTION THEN TURNS TO ANOTHER STRONG SHORT WAVE TROUGH DIGGING
FROM MANITOBA INTO ONTARIO AND ACROSS THE NORTHERN LAKES INTO
TUESDAY...WHICH RESULTS IN DEEP SURFACE LOW PRESSURE PASSING
NORTHEAST OF THE GREAT LAKES MONDAY NIGHT AND TUESDAY AND TIGHTENING
OF THE SURFACE PRESSURE GRADIENT ACROSS THE MIDWEST. WEST-SOUTHWEST
WINDS WILL BECOME BLUSTERY MONDAY NIGHT SUPPORTING STEADY OR SLOWLY
RISING TEMPERATURES MONDAY NIGHT ESPECIALLY ACROSS THE NORTH WHERE
WINDS WILL BE STRONGEST. TEMPERATURES WILL RISE INTO THE 25-30
DEGREE RANGE DURING THE DAY TUESDAY BEFORE THE COLD FRONT TRAILING
THE CANADIAN LOW MOVES THROUGH LATE IN THE DAY...THOUGH THE GUSTY
SOUTHWEST WINDS TO 35 MPH AT TIMES WILL MAINTAIN A RAW FEEL TO THE
DAY WITH WIND CHILLS IN THE TEENS AT BEST (ABOVE ZERO AT LEAST).
CLOUDS WILL INCREASE TUESDAY MORNING AHEAD OF THE APPROACHING FRONT
WITH SCATTERED SNOW SHOWERS OR FLURRIES AT TIMES DURING THE DAY. THE
COLD FRONT MOVES THROUGH BY EARLY TUESDAY EVENING...WITH BLUSTERY
NORTHWEST WINDS BRINGING COLDER AIR BACK INTO THE REGION AT LEAST IN
A GLANCING NATURE INTO WEDNESDAY WITH SINGLE DIGIT TEMPS TUESDAY
NIGHT AND HIGHS IN THE TEENS AND WIND CHILLS IN THE POSITIVE SINGLE
DIGITS WEDNESDAY. A WEAK CLIPPER SYSTEM IS CURRENTLY PROGGED TO MOVE
JUST WEST OF THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT...WHICH MAY
BRING SOME LIGHT SNOW TO WESTERN PARTS OF THE CWA. LOW LEVEL WINDS
ALSO LOOK TO VEER MORE NORTH-NORTHEAST WHICH MAY BRING SOME LIGHT
SNOW SHOWERS INTO NORTHWEST INDIANA AND EVEN PARTS OF NORTHEAST
ILLINOIS. NOT TOO EXCITED ABOUT ACCUMULATIONS WITH LAKE EFFECT AT
THIS TIME...AS INVERSION HEIGHTS REMAIN FAIRLY LOW.
RATZER
&&
.LONG TERM...
234 PM CST
THURSDAY THROUGH SUNDAY...
REINFORCEMENT OF ARCTIC AIR CONTINUES THURSDAY AND THURSDAY NIGHT AS
ANOTHER SHORT WAVE TROUGH DIGS SOUTHEAST AND MAINTAINS DEEP LARGE
SCALE TROUGH OVER THE EASTERN CONUS. SURFACE HIGH BUILDS SOUTHEAST
FROM THE NORTHERN PLAINS THURSDAY...INTO DOWNSTATE ILLINOIS BY
FRIDAY MORNING. 850 HPA TEMPS DROP INTO THE -16 TO -20 C RANGE
DURING THE PERIOD WITH LIGHT WINDS OF THE SURFACE RIDGE AND CLEARING
SKIES AGAIN EXPECTED TO PRODUCE SUB-ZERO TEMPERATURES BY SUNRISE
FRIDAY MORNING AND HIGHS ONLY IN THE TEENS FRIDAY...WHICH FOR THE
END OF FEBRUARY IS A GOOD 20-25 DEGREES BELOW OUR NORMAL HIGHS WHICH
WOULD BE NEAR 40 FOR THE END OF THE MONTH.
LONGER RANGE MODEL SOLUTIONS DO OFFER SOME HOPE FOR A LITTLE
MODERATION IN TEMPERATURES NEXT WEEKEND...WITH A TROUGH ELONGATING
AND BECOMING CUT-OFF IN THE SOUTHWEST CONUS AND A BROAD UPPER RIDGE
DEVELOPING ACROSS THE SOUTHEASTERN CONUS SATURDAY AND SUNDAY. THUS
OUR ARCTIC HIGH EVENTUALLY MOVES OFF THE ATLANTIC COAST WITH
SOUTHERLY FLOW DEVELOPING ACROSS THE LOWER AND MIDDLE MISSISSIPPI
VALLEY BY SUNDAY. OF COURSE THIS HELPS TO FEED MILDER AND MORE HUMID
AIR NORTHWARD...FOR A NORTHERN STREAM UPPER TROUGH AND SURFACE LOW
WHICH WOULD ALSO BRING PRECIPITATION TO THE AREA SATURDAY NIGHT AND
SUNDAY. AT THIS DISTANCE HAVE MAINTAINED A CONSERVATIVE APPROACH
WITH TEMPS INTO THE MID-30S SUNDAY AND POTENTIAL FOR SOME SNOW...
THOUGH IF THESE MODEL TRENDS PERSIST IT COULD BE MILDER WITH MIXED
PRECIP OR RAIN ESPECIALLY ACROSS OUR SOUTHEAST.
RATZER
&&
.CLIMATE...
RECORD COLD TEMPERATURES ARE POSSIBLE IN ROCKFORD ON MONDAY
FEBRUARY 23RD.
RECORD LOW FOR 2/23: -12 IN 1910.
RECORD LOW MAX FOR 2/23: 17 IN 1934.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LOW-LEVEL WIND SHEAR LATE MONDAY NIGHT.
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE ACROSS THE MISSOURI RIVER VALLEY EARLY THIS MORNING
WILL MOVE OVER THE AREA MONDAY MORNING AND THEN INCH EAST OF THE
AREA MONDAY NIGHT. WITH THAT WINDS WILL TURN FROM NORTHWEST TO
WEST IN THE MORNING TO SOUTHWEST BY AFTERNOON. WINDS SPEEDS WILL
INCREASE MONDAY NIGHT AS THE PRESSURE GRADIENT TIGHTENS. A STRONG
LOW-LEVEL JET WILL DEVELOP ALOFT LATER MONDAY NIGHT AND SHOULD SET
THE STAGE FOR LOW-LEVEL WIND SHEAR WITHIN THE 900-1500FT LAYER AS
SPEEDS RAPIDLY INCREASE WITH AN INVERSION.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH IN ALL ELEMENTS.
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...STRONG/GUSTY SW WINDS. MVFR CIGS POSSIBLE LATE.
WEDNESDAY THROUGH SATURDAY...PRIMARILY VFR.
MTF/IZZI
&&
.MARINE...
332 PM CST
HIGH PRESSURE MOVING ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST
THIS AFTERNOON INTO THE EVENING IS ALLOWING FOR NORTHERLY WINDS OF
15 TO 25 KT TO CONTINUE THIS AFTERNOON...WITH THESE SPEEDS TO
LIKELY CONTINUE FOR MUCH OF TONIGHT. THIS HIGH WILL DRIFT
SOUTHEAST THROUGH THE UPPER MIDWEST AND MID MISSISSIPPI VALLEY
TONIGHT THROUGH MONDAY AND THEN REACH THE MID ATLANTIC WEST TO THE
SOUTHERN PLAINS BY EARLY TUESDAY MORNING. AS THIS OCCURS...WINDS
WILL TURN WEST AND THEN SOUTHWEST SLIGHTLY DIMINISHING ON MONDAY
MORNING...BUT THEN INCREASE ONCE AGAIN MONDAY AFTERNOON WITH TO 30
KT WINDS LIKELY LATE IN THE AFTERNOON. WINDS WILL REALLY INCREASE
MONDAY NIGHT INTO TUESDAY OUT AHEAD OF SOUTHWARD MOVING LOW
PRESSURE OVER ONTARIO...WITH GALES LIKELY. HAVE ISSUED A GALE AND
FREEZING SPRAY WARNING OVER THE ENTIRE LAKE MONDAY NIGHT THROUGH
TUESDAY NIGHT AND HAVE NOT ISSUED A GALE WARNING FOR THE NEARSHORE
AT THIS TIME. HOWEVER...THEY DO APPEAR TO BE A POSSIBILITY VERY
EARLY TUESDAY MORNING AND WILL NEED TO CONTINUE MONITORING THIS
PERIOD FOR POSSIBLE PREVAILING GALES...AND EVEN FOR A LONGER
DURATION. DO HAVE HIGH CONFIDENCE WITH THE START TIME OF THE GALES
ACROSS THE LAKE BUT HAVE LOWER CONFIDENCE WITH THE END TIME...WITH
THE GALES POSSIBLY LASTING LONGER INTO TUESDAY NIGHT.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 9 AM MONDAY.
IN...WIND CHILL ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 9
AM MONDAY.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM MONDAY TO 3 AM
WEDNESDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ669-LMZ671-LMZ673-
LMZ675-LMZ777-LMZ779-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9
PM MONDAY TO 3 AM WEDNESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...6 PM MONDAY TO 3 AM WEDNESDAY.
HEAVY FREEZING SPRAY WARNING...LMZ261-LMZ362-LMZ364-LMZ366-
LMZ563-LMZ565-LMZ567-LMZ868...6 PM MONDAY TO 3 AM WEDNESDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742...9 PM MONDAY TO NOON
TUESDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...MIDNIGHT TUESDAY TO NOON
TUESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1136 PM CST Sun Feb 22 2015
.UPDATE...
ISSUED AT 857 PM CST SUN FEB 22 2015
Strong Arctic high pressure will continue to build into the area
overnight on schedule. Surface temperatures are still above zero,
but wind speeds have been sufficient to drop Wind Chill values
below zero across most of the forecast area. While wind speeds
will die off some overnight as the high approaches and pressure
gradient relaxes, sub-zero air temperatures will allow Wind Chill
values to fall to advisory levels.
Going forecast is in good shape. Only a few tweaks for the latest
hourly trends are required.
&&
.SHORT TERM...(Tonight)
ISSUED AT 240 PM CST SUN FEB 22 2015
Another Arctic air mass settling into our area for tonight and
Monday bringing bitterly cold wind chills tonight through the
mid-morning hours of Monday with values in the -15 to -25 degree
range. Latest upstream observations mostly in the single digits
across north central through northeast Iowa with wind gusts up
to 30 mph at times. Early morning lows are expected to dip to
-2 in the far south to as low as -8 across the north just before
dawn Monday. The center of the Arctic high is forecast by models
to drift into southeast Iowa by 12z Monday with the surface ridge
axis extending northeast into northern Illinois. Forecast soundings
and the latest HRRR model suggests the cloud cover we have over the
area this afternoon will drift east and south later this evening
with mainly some cirrus for the first half of the night and then
a mostly clear sky is expected after midnight most areas. Current
Wind Chill Advisory will remain in place for late tonight through
9AM Monday morning.
&&
.LONG TERM...(Monday through Sunday)
ISSUED AT 240 PM CST SUN FEB 22 2015
As the center of the cold air mass drifts across the area tomorrow,
look for winds to diminish during the day but temperatures will be
slow to rise with afternoon highs struggling to 10 to 15. The high
should be moving off to our east by afternoon and early evening
with our next surface low and cold front tracking across southern
Canada southwest through the Northern Plains. Early in the evening,
surface winds will be light enough for our usual tank with early
evening temperatures before we see a steady or slowly rising trend
across the north and west, while further east with a lighter wind
flow, early morning lows will dip several degrees below zero Monday
night into Tuesday morning. As the deep surface low tracks north
of Lake Superior on Tuesday, a gusty south to southwest wind should
help the mercury climb into the mid 20s far east to the low to mid
30s far west where we should be able to mix out fairly well during the
afternoon. With the better upper forcing remaining well to our north
and very limited moisture, models not showing much if any precip
associated with the boundary as it swings across our area late in
the day, except for the GFS which continues to produce a large area
of 0.01 qpf with this system. Not worth much more than a chance for
flurries and will continue with that for later in the day on Tuesday.
Then we will see another cold air mass build gradually southeast thru
midweek.
The GFS and latest ECMWF continue to show a weak shortwave racing
southeast into the Plains on Wednesday along the periphery of the
next batch of cold air for the remainder of the work week. The
GFS keeps any precip associated with this wave to our west and
south while the latest ECMWF has trended in that direction as well
but does bring in some light QPF late Wednesday/Wednesday evening.
Based on the latest westward shift with the ECMWF, will only have
slight chances Wednesday night for light snow. Colder temperatures
filter into the area again Wednesday night with early morning lows
dropping into the single digits with wind chills dropping to near
-10 by Thursday morning.
And a real surprise here, the well below normal temperatures are
expected to hold on across our area through at least the end of
the work week with daytime highs in the teens and early morning
lows dropping into the single digits with a few below zero readings
again possible early Friday morning. Both the GFS and ECMWF indicate
a significant change to the upper pattern with more of a southwesterly
flow developing over the weekend which will lead to an increasing
threat for precipitation. Models showing more agreement from what
we saw yesterday with snow chances moving in starting on Saturday
night with the threat for snow or rain on Sunday with warming
temperatures. Even seeing some better agreement with the ensemble
members with respect to the pattern change along with timing of
the precip into our area later Saturday through Sunday. Temperatures
will start to turn around on Saturday and Sunday, but still average
below the normal highs of 40 to 45 across the area for late February.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1136 PM CST SUN FEB 22 2015
VFR aviation weather Condtions are expected to prevail across the
central Illinois terminals through the 06Z TAF valid time.
Mid/high level CIGS will gradually diminish with time, with mostly
clear skies expected by midday Monday. Northerly breezes from
10-15 kts tonight will become light/variable by Monday afternoon
as high pressure builds across the area. Then, as the high begins
to pull away Monday evening, winds will swing around to the
southwest.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until 9 AM CST Monday FOR ILZ027>031-036>038-
040>057-061>063-066>068-071>073.
&&
$$
UPDATE...Bak
SHORT TERM...Smith
LONG TERM...Smith
AVIATION...Bak
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1128 PM CST SUN FEB 22 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 235 PM CST SUN FEB 22 2015
MAIN ISSUE OF CONCERN IN THE SHORT TERM IS THE WIND CHILL ADVISORY
FOR LATE TONIGHT INTO MONDAY MORNING. THE LATEST SHORT TERM
GUIDANCE KEEPS THE STRONGEST WINDS AND COLDEST TEMPERATURES ACROSS
PORTIONS OF SOUTHEAST MISSOURI AND MOST OF SOUTHERN ILLINOIS.
AFTER COLLABORATING WITH WFOS LSX AND LMK DECIDED TO EXPAND THE
ADVISORY A ROW OF COUNTIES FARTHER SOUTH ACROSS ILLINOIS AND THEN
FROM PERRY SOUTHWARD THROUGH SCOTT AND STODDARD IN MISSOURI. IT
LOOKS A LITTLE FUNKY IN MISSOURI...BUT THAT IS DUE TO THE CORE OF
STRONGER WINDS IN THAT REGION. THE WIND CHILLS CURRENTLY FORECAST
OVER SOUTHWEST INDIANA AND ADJACENT PORTIONS OF WEST KENTUCKY DO
NOT QUITE GET DOWN TO 10 BELOW...BUT LEFT THAT ALONE BECAUSE IT
WILL BE CLOSE.
ALTHOUGH WINDS ARE EXPECTED TO BE LIGHT MONDAY NIGHT...SOUTH WINDS
WILL INCREASE QUICKLY TUESDAY MORNING AND WITH THE LOWS WELL INTO
THE SINGLE DIGITS...MUCH OF SOUTHERN ILLINOIS AND SOUTHWEST
INDIANA MAY SEE SOME NEGATIVE WIND CHILLS FOR A FEW HOURS TUESDAY
MORNING. WILL GIVE THIS A MENTION IN THE HWO.
KEPT A MENTION OF FLURRIES IN THE FORECAST LATE THIS AFTERNOON AND
EVENING ROUGHLY ALONG AND SOUTH OF A LINE FROM VAN BUREN MISSOURI
TO MURRAY KENTUCKY. THE HRRR AND WRF RUNS REALLY DRY UP ANY ECHOES
AS THEY ENTER OUR AREA...AND THERE HASN`T BEEN ANY REPORTS OF SNOW
REACHING THE GROUND THIS SIDE OF KJLN. WON`T BE COMPLETELY
SURPRISED TO SEE A FEW FLURRIES...BUT MEASURABLE SNOWFALL IS
HIGHLY UNLIKELY.
TEMPERATURES HAVE REMAINED NEARLY STEADY ACROSS THE REGION
TODAY. FIGURE THAT COLD ADVECTION WILL KICK IN AS WE HEAD INTO THE
EVENING HOURS...BUT ENDED UP RAISING LOWS A BIT FOR TONIGHT. MOS
GUIDANCE IS GIVING QUITE A RANGE FOR FIRST PERIOD LOWS.
LOOKING UPSTREAM THIS AFTERNOON...IT APPEARS THAT GUIDANCE FOR
HIGHS ON MONDAY IS A BIT TOO COLD. LEANED TOWARD THE LESS COLD
NAM/MET NUMBERS...BUT IT WILL STILL STRUGGLE TO GET THROUGH THE
TEENS IN MOST LOCATIONS. WIND CHILLS WILL REMAIN IN THE SINGLE
DIGITS ABOVE ZERO THROUGH THE AFTERNOON.
NOT SURE IF MID/HIGH CLOUDS WILL BE THICK ENOUGH TO HOLD
TEMPERATURES UP MUCH MONDAY NIGHT OR NOT. WINDS SHOULD BE LIGHT OR
CALM WITH HIGH PRESSURE OVERHEAD...SO IT WILL BE ANOTHER COLD ONE.
DEFINITELY WENT TO THE COLD SIDE OF GUIDANCE MONDAY NIGHT.
SOUTHWEST WINDS WILL INCREASE ACROSS THE AREA TUESDAY...SO A
DECENT WARM UP IS FORECAST. UNFORTUNATELY WITH TEMPERATURES
STARTING OFF SO COLD...IT WILL STRUGGLE TO GET TO THE FREEZING
MARK.
A DISTURBANCE WILL DIVE SOUTHEAST THROUGH THE GREAT LAKES TUESDAY
NIGHT. THIS WILL BRING AN INCREASE IN CLOUDS AND A WEAK COLD
FRONTAL PASSAGE THROUGH OUR REGION. LOWS TUESDAY NIGHT WILL
ACTUALLY BE MILD...RELATIVELY SPEAKING. SOME LOCATIONS WILL STAY
ABOVE 20 ALL NIGHT.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 235 PM CST SUN FEB 22 2015
ANOTHER SURGE OF COLD HIGH PRESSURE WILL BUILD SOUTHEAST WEDNESDAY
INTO WEDNESDAY NIGHT BEHIND A WEAK COLD FRONT. THE CENTER OF THE
HIGH WILL MOVE SOUTHEAST THROUGH THE END OF THE WORK WEEK AND SETTLE
OVER THE OHIO VALLEY BY 00Z SATURDAY. TEMPERATURES WILL AGAIN DROP
OFF TO EVEN COLDER THAN SEASONAL NORMALS, WITH HIGHS THURSDAY AND
FRIDAY ONLY IN THE 20S WITH LOWS IN THE SINGLE DIGITS TO MIDDLE
TEENS.
MODELS SHOW THE HIGH DRIFTING EASTWARD FOR THE EARLY PART OF THE
WEEKEND. TEMPERATURES WILL MODERATE BACK IN THE 30S AHEAD OF OUR
NEXT WEATHER SYSTEM. ECMWF AND GFS DIFFER ON TIMING AND TRACK OF A
LOW PRESSURE SYSTEM, WITH ECMWF BEING THE FASTER OF THE MODELS WITH
MORE SUBSTANTIAL QPF. ECMWF SHOWS WIDESPREAD PRECIPITATION ACROSS
THE PAH FORECAST AREA SATURDAY NIGHT, WHILE GFS JUST SHOW MINIMAL
QPF REACHING INTO OUR SOUTHERN COUNTIES LATE SATURDAY NIGHT. BY
SUNDAY BOTH MODELS SHOW DECENT QPF ACROSS THE ENTIRE PAH FA. JUST
WENT WITH SLIGHT CHANCE POPS FOR LIGHT SNOW SATURDAY NIGHT,
INCREASING TO CHANCE POPS FOR RAIN ON SUNDAY. BOTH MODELS YESTERDAY
SHOWED THIS SYSTEM AFFECTING OUR REGION FRIDAY NIGHT INTO SATURDAY,
SO WE STILL ARE FAIRLY LOW CONFIDENCE ON TIMING. THE LATER TIMING
DOES AT LEAST ALLOW SOME "WARMER" TO GET INTO OUR AREA AHEAD OF THE
SYSTEM, THUS LEADING TO LESS WINTRY PRECIP.
&&
.AVIATION...
ISSUED AT 1128 PM CST SUN FEB 22 2015
VFR CONDITIONS TO DOMINATE WITH WEAKENING SURFACE WIND GRADIENT
ACROSS THE WFO PAH TAF SITES. WIND GUSTS SHOULD DIMINISH ACROSS
THE AREA BY 12Z.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR ILZ075>078-080>091.
MO...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR MOZ076-086-087-110-
111.
IN...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR INZ081-082-085>088.
KY...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR KYZ010-014-015-
018>020.
&&
$$
SHORT TERM...DRS
LONG TERM...RST
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
100 PM CST MON FEB 23 2015
.AVIATION...
FOR THE 23/18Z TAFS...WINTRY MIX OF PRECIPITATION WILL CONTINUE TO
AFFECT OUR AREA TERMINALS THROUGH THE FIRST HALF OF THE TAF PERIOD
EXCEPT LFK WHERE IT APPEARS WE MAY STAY WITH JUST LIGHT RAIN UNTIL
THE OVERNIGHT HOURS. CIGS/VSBYS VARY WIDELY BUT ARE MOSTLY MVFR/IFR
AND WILL REMAIN SO THROUGH THE TAF PERIOD. PRECIPITATION WILL TAPER
OFF FROM WEST TO EAST THROUGH THE EVENING AND OVERNIGHT HOURS BUT
CIGS WILL STILL REMAIN MOSTLY IFR. WINDS WILL MAINTAIN A NORTHERLY
COMPONENT AND BEGIN TO DECREASE AFTER 24/00Z TO AROUND 5 KTS. /19/
&&
.PREV DISCUSSION... /ISSUED 1047 AM CST MON FEB 23 2015/
DISCUSSION...
FREEZING LINE CURRENTLY ALONG THE INTERSTATE 20 CORRIDOR FROM
JACKSONVILLE TEXAS TO MONROE LOUISIANA. PRECIPITATION ALONG AND
NORTH OF INTERSTATE 20 IN THE FORM OF SNOW ACROSS SOUTHEAST
OKLAHOMA...AND A MIX OF SLEET/FREEZING RAIN/RAIN ELSEWHERE.
TEMPERATURES CONTINUING TO FALL AREAWIDE. LOOKS LIKE THIS PUSH OF
PRECIPITATION MAY BE THE MAIN EVENT. HRRR AND GFS MODELS TEND TO
SUGGEST A SECOND SURGE OF MOISTURE COMING UP FROM SOUTHEAST TEXAS
LATER THIS AFTERNOON...WHILE NAM REMAINS THE OUTLIER WITH
PRECIPITATION CONTINUING ACROSS THE SOUTHEAST OKLAHOMA AND SOUTHERN
ARKANSAS. FOR THIS UPDATE...WILL MAINTAIN WARNINGS AND ADVISORIES
AS IS. ONLY CHANGE WAS TO DECREASE POPS ACROSS DEEP EAST TEXAS AND
WEST CENTRAL LOUISIANA BASED ON CURRENT RADAR TRENDS. /05/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 27 38 34 41 30 / 60 30 40 60 10
MLU 27 37 34 39 29 / 60 30 40 60 10
DEQ 24 37 30 41 29 / 50 20 20 50 10
TXK 26 37 31 41 28 / 50 20 20 60 10
ELD 24 38 31 40 27 / 60 20 20 60 10
TYR 27 37 33 41 32 / 60 20 40 60 10
GGG 28 39 33 41 31 / 60 20 40 60 10
LFK 29 41 34 41 33 / 60 30 40 60 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: ARZ070>072.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: ARZ050-051-059>061-073.
LA...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: LAZ001>003.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: LAZ004>006-010>014-017>022.
OK...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: OKZ077.
TX...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: TXZ096-097-108>112-124>126-136>138.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: TXZ149>153-165>167.
&&
$$
19
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1047 AM CST MON FEB 23 2015
.DISCUSSION...
FREEZING LINE CURRENTLY ALONG THE INTERSTATE 20 CORRIDOR FROM
JACKSONVILLE TEXAS TO MONROE LOUISIANA. PRECIPITATION ALONG AND
NORTH OF INTERSTATE 20 IN THE FORM OF SNOW ACROSS SOUTHEAST
OKLAHOMA...AND A MIX OF SLEET/FREEZING RAIN/RAIN ELSEWHERE.
TEMPERATURES CONTINUING TO FALL AREAWIDE. LOOKS LIKE THIS PUSH OF
PRECIPITATION MAY BE THE MAIN EVENT. HRRR AND GFS MODELS TEND TO
SUGGEST A SECOND SURGE OF MOISTURE COMING UP FROM SOUTHEAST TEXAS
LATER THIS AFTERNOON...WHILE NAM REMAINS THE OUTLIER WITH
PRECIPITATION CONTINUING ACROSS THE SOUTHEAST OKLAHOMA AND SOUTHERN
ARKANSAS. FOR THIS UPDATE...WILL MAINTAIN WARNINGS AND ADVISORIES
AS IS. ONLY CHANGE WAS TO DECREASE POPS ACROSS DEEP EAST TEXAS AND
WEST CENTRAL LOUISIANA BASED ON CURRENT RADAR TRENDS. /05/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 32 27 38 34 41 / 80 60 30 40 60
MLU 30 27 37 34 39 / 80 60 30 40 60
DEQ 28 24 37 30 41 / 80 50 20 20 50
TXK 30 26 37 31 41 / 80 50 20 20 60
ELD 28 24 38 31 40 / 80 60 20 20 60
TYR 32 27 37 33 41 / 80 60 20 40 60
GGG 33 28 39 33 41 / 80 60 20 40 60
LFK 36 29 41 34 41 / 80 60 30 40 60
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: ARZ070>072.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: ARZ050-051-059>061-073.
LA...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: LAZ001>003.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: LAZ004>006-010>014-017>022.
OK...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: OKZ077.
TX...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: TXZ096-097-108>112-124>126-136>138.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: TXZ149>153-165>167.
&&
$$
05/05
AREA FORECAST DISCUSSION
NWS GRAY ME
1047 PM EST TUE FEB 24 2015
.SYNOPSIS...
WEAK LOW PRESSURE WILL PASS EAST OF THE AREA LATE TONIGHT AND
WEDNESDAY....AND WILL PRODUCE A PERIOD OF SNOW...ENDING BY
WEDNESDAY AFTERNOON. HIGH PRESSURE FOLLOWS THIS SYSTEM FOR
THURSDAY INTO THE START OF NEXT WEEKEND. THE NEXT CHANCE FOR
PRECIPITATION WILL COME AS HIGH PRESSURE RETREATS LATE IN THE
WEEKEND OR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
1040 PM UPDATE...VERY LITTLE CHANGE TO THE GOING FORECAST.
TIGHTENED UP THE EXPECTED SNOWFALL GRADIENT FOR THE OVERNIGHT. THIS
BASED ON LATEST FEW RUNS OF THE HRRR...RAP...AND 00Z NAM GUIDANCE
AS WELL AS REGIONAL RADAR IMAGERY. BUT I ADMIT IT IS GOING TO BE A
CLOSE CALL. ALMOST CERTAINLY A CASE OF THE HAVES AND HAVE NOTS
GIVEN THE EXPECTED SNOWFALL GRADIENT BASED ON LATEST RADAR IMAGERY
IN THE VICINITY OF EASTERN LONG ISLAND. RADAR WATCHING ACROSS
RI/SE MASS OVER THE COURSE OF THE NEXT TWO HOURS WILL BE THE KEY
TO UPDATING POPS/AMTS ASSOCIATED WITH THE WESTERN EDGE OF THE
SNOW SHIELD. WHOMEVER GETS IN IN IT MAY SNOW HEAVILY FOR AN HOUR
OR TWO...WITH GOOD ACCUMULATORS AS FAR AS SNOWFLAKE TYPES GO. WE
MAINLY EXPECT THIS POSSIBILITY NEAR AND EAST OF I-95.
930 PM UPDATE...NO CHANGES TO THE FORECAST AT THIS TIME.
AWAITING THE ARRIVAL OF THE 00Z RGEM AND NEW HRRR/RAP RUNS BEFORE
MAKING ANY CHANGES THE FORECAST THIS EVENING. WHILE RAPID UPDATE
MESOSCALE GUIDANCE LIKE THE HRRR AND RAP ARE STILL EAST WITH ANY
SNOWFALL...THE RADAR IMAGERY SOUTH OF LONG ISLAND NY SAYS PERHAPS
OTHERWISE. STILL EXPECTING THE MID COAST OF MAINE TO DO PRETTY
WELL OVERNIGHT...JUST NOT COMPLETELY SURE IF ACCUMULATING SNOW
MAKES AN APPRARANCE IN PSM AND PWM FOR EXAMPLE.
615 PM UPDATE...HAVE UPDATED THE NEAR TERM FORECAST BASED ON
LATEST TRENDS IN OBSERVATIONAL DATA AS WELL AS NEW MESOSCALE
MODEL DATA. IT WILL BE INTERESTING TO SEE HOW THE SNOWFALL PANS
OUT LATER TONIGHT. 18Z MODEL RUNS PRETTY MUCH STATUS QUO.
HOWEVER...LATEST FEW RUNS OF THE RAP AND HRRR KEEP MOST OF IT
OFFSHORE. HOPEFULLY THE TWO CAMPS WILL MERGE OVER THE NEXT COUPLE
OF HOURS.
PREVIOUSLY...
WEAK WAVES IN THE SRN AND NRN STREAM PASS TO OUR NW AND SE LATE
TONIGHT /BEFORE EVENTUALLY PHASING TO OUR EAST ON WED/ AND WILL
BRING A PERIOD OF LIGHT OR SHSN TO MOVE OVER THE REGION...MAINLY
AFTER MIDNIGHT. MODELS ARE IN GOOD AGREEMENT THAT AS THE SYSTEMS
INTERACT LATE TONIGHT WE WILL START TO SEE SOME MID LVL
FRONTOGENESIS FORM JUST OFFSHORE. THIS WILL LKLY FORM A BAND OF SNOW
OFF THE COAST...WHICH WILL GRAZE COASTAL AREAS E OF KPWM AND WILL
IMPACT THE MID COAST AND ESPECIALLY THE PENOBSCOT BAY REGION WITH 3
TO 6 INCHES OF SNOW. AS YOU MOVE FURTHER NW FROM THIS AREA AMTS DROP
OFF QUICKLY...WITH 1-3" FROM SEACOAST NH NE THROUGH THE PORTLAND
AREA...THE CAPITAL REGION...AND INTO SRN SOMERSET COUNTY. EXPECT AN
INCH OR LESS ACROSS THE REST OF NH AND INTERIOR WRN ME. THE BULK OF
THE SNOW LOOKS TO FALL BETWEEN 06Z AND 12Z. IN THE ADVISORY AREA IT
MAY LINGER UNTIL ABOUT 15Z...SO COULD SEE A QUICK 4-6" OF SNOW HERE
DURING PRE-DAWN AND INTO THE MORNING COMMUTE. TEMPS WILL DROP OFF A
BIT THIS EVENING...MORE SO IN THE ERN AND NRN ZONES WHERE LESS
CLOUDS AND A PERIOD WITHOUT ANY REAL BL FLOW WILL ALLOW SOME RAD
COOLING. BUT TEMPS HERE WILL STALL AND SHOULD BEGIN TO RISE NEAR THE
COAST AFTER MIDNIGHT.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
SOME LIGHT SNOW MAY LINGER OUTSIDE THE ADV AREA FOR THE EARLY
MORNING...BUT SHOULD BE CLOSE TO OVER BY 12Z...WITH THE EXCEPTION
OF THE ADVISED MID-COAST AREA...WHERE SNOW WILL LINGER THRU ABOUT
14-15Z. MODELS INDICATE RAPID CLEARING FROM W-E BEHIND THIS SYSTEM
AS W WINDS DOWNSLOPE AND DRIER AIR MOVES IN. WITH THE SUN AND THE
DOWNSLOPE...WILL SEE TEMPS RISE IN THE UPPER 20S TO LOWER 30S ON THE
COASTAL...AND INTO THE LOW TO MID 20S IN THE MTNS AND FOOTHILLS.
THE WINDS DIE OFF AROUND SUNSET WITH MAINLY CLEAR SKIES AND LIGHT
WINDS SHOULD SEE SOME GOOD RAD COOLING...BUT WITH WARMER AIR
ALOFT...WILL NOT BE AS COLD AS MON MORNING WITH LOWS SINGLE ABV ZERO
NEAR THE COAST...AND SINGLE DIGITS BELOW ZERO INLAND.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
LOW PRESSURE WILL MOVE
SOUTH OF THE REGION DURING THURSDAY. AT THIS POINT IT LOOKS LIKE
CLOUDS FROM THIS SYSTEM WILL CROSS THE AREA BUT THE PRECIPITATION
SHIELD WILL STAY SOUTH OF THE AREA. THE GFS WOULD GIVE THE
POSSIBILITY OF A FEW FLURRIES BUT THE EURO KEEPS ALL PRECIPITATION
SOUTH. REINFORCING COLD COMES IN BEHIND THIS SYSTEM FOR FRIDAY AND
SATURDAY AS HIGH PRESSURE BUILD OVER THE REGION.
FOR SUNDAY...AS THE HIGH MOVES EAST OF THE AREA CLOUDS WILL INCREASE
AND TEMPERATURES WILL MODERATE SOME. A WEAK OVERRUNNING SETUP FORMS
SUNDAY NIGHT THAT COULD PRODUCE A PERIOD OF SNOW. ANOTHER WEAK AREA
OF HIGH PRESSURE BRIEFLY BUILDS IN FOR MONDAY.
MODELS AGREE ON BRINGING ANOTHER AREA OF LOW PRESSURE OVER THE
AREA LATE MONDAY NIGHT AND TUESDAY. WITH MODERATING
TEMPERATURES...PRECIPITATION TYPE COULD BECOME A CHALLENGE BY LATE
TUESDAY OVER SOUTHERN AREAS.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM...CONDITIONS DETERIORATE TO MVFR LATE THIS EVENING AND
EVENTUALLY IFR IN -SN AT ALL BUT KLEB/KHIE WHERE IT WILL LKLY STAY
MAINLY MVFR IN -SHSN. CONDS WILL IMPROVE QUICKLY TO VFR DURING WED
MORNING BEHIND THIS SYSTEM...WHICH WILL PERSIST INTO WED NIGHT.
LONG TERM...AN AREA OF MVFR CLOUDS WILL BE POSSIBLE THURSDAY AS
LOW PRESSURE MOVES SOUTH OF THE REGION. HIGH PRESSURE WILL RESULT
IN MOSTLY VFR CONDITIONS FRIDAY AND SATURDAY. A WARM FRONT COULD
RESULT IN MVFR CONDITIONS ON SUNDAY AND SUNDAY NIGHT. A PERIOD OF
SNOW IS POSSIBLE SUNDAY NIGHT.
&&
.MARINE...
SHORT TERM...WILL SEE AN INCREASE IN SW FLOW...WHICH COULD PRODUCE
A FEW GUSTS TO NEAR 25 KT LATE TONIGHT...BUT WILL HOLD OFF THE SCA
FOR NOW. BETTER CHC FOR SCA WILL BE IN THE W FLOW BEHIND THE
SYSTEM FROM LATE WED MORNING INTO WED EVE.
LONG TERM...
LOW PRESSURE WILL PASS SOUTH OF THE WATERS THURSDAY. HIGH PRESSURE
WILL BUILD OVER THE WATERS FRIDAY AND SATURDAY FOLLOWED BY THE
APPROACH OF A WARM FRONT SUNDAY. WINDS AND WAVES ARE EXPECTED TO
REMAIN BELOW SCA LEVELS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL NOON EST WEDNESDAY FOR MEZ022-
026>028.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 11 PM EST WEDNESDAY FOR
ANZ151-153.
SMALL CRAFT ADVISORY UNTIL 11 PM EST WEDNESDAY FOR ANZ150-152-
154.
&&
$$
NEAR TERM UPDATE...EKSTER
SHORT TERM...CEMPA
LONG TERM...LULOFS
AREA FORECAST DISCUSSION
NWS GRAY ME
930 PM EST TUE FEB 24 2015
.SYNOPSIS...
WEAK LOW PRESSURE WILL PASS EAST OF THE AREA LATE TONIGHT AND
WEDNESDAY....AND WILL PRODUCE A PERIOD OF SNOW...ENDING BY
WEDNESDAY AFTERNOON. HIGH PRESSURE FOLLOWS THIS SYSTEM FOR
THURSDAY INTO THE START OF NEXT WEEKEND. THE NEXT CHANCE FOR
PRECIPITATION WILL COME AS HIGH PRESSURE RETREATS LATE IN THE
WEEKEND OR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
930 PM UPDATE...NO CHANGES TO THE FORECAST AT THIS TIME.
AWAITING THE ARRIVAL OF THE 00Z RGEM AND NEW HRRR/RAP RUNS BEFORE
MAKING ANY CHANGES THE FORECAST THIS EVENING. WHILE RAPID UPDATE
MESOSCALE GUIDANCE LIKE THE HRRR AND RAP ARE STILL EAST WITH ANY
SNOWFALL...THE RADAR IMAGERY SOUTH OF LONG ISLAND NY SAYS PERHAPS
OTHERWISE. STILL EXPECTING THE MID COAST OF MAINE TO DO PRETTY
WELL OVERNIGHT...JUST NOT COMPLETELY SURE IF ACCUMULATING SNOW
MAKES AN APPRARANCE IN PSM AND PWM FOR EXAMPLE.
615 PM UPDATE...HAVE UPDATED THE NEAR TERM FORECAST BASED ON
LATEST TRENDS IN OBSERVATIONAL DATA AS WELL AS NEW MESOSCALE
MODEL DATA. IT WILL BE INTERESTING TO SEE HOW THE SNOWFALL PANS
OUT LATER TONIGHT. 18Z MODEL RUNS PRETTY MUCH STATUS QUO.
HOWEVER...LATEST FEW RUNS OF THE RAP AND HRRR KEEP MOST OF IT
OFFSHORE. HOPEFULLY THE TWO CAMPS WILL MERGE OVER THE NEXT COUPLE
OF HOURS.
PREVIOUSLY...
WEAK WAVES IN THE SRN AND NRN STREAM PASS TO OUR NW AND SE LATE
TONIGHT /BEFORE EVENTUALLY PHASING TO OUR EAST ON WED/ AND WILL
BRING A PERIOD OF LIGHT OR SHSN TO MOVE OVER THE REGION...MAINLY
AFTER MIDNIGHT. MODELS ARE IN GOOD AGREEMENT THAT AS THE SYSTEMS
INTERACT LATE TONIGHT WE WILL START TO SEE SOME MID LVL
FRONTOGENESIS FORM JUST OFFSHORE. THIS WILL LKLY FORM A BAND OF SNOW
OFF THE COAST...WHICH WILL GRAZE COASTAL AREAS E OF KPWM AND WILL
IMPACT THE MID COAST AND ESPECIALLY THE PENOBSCOT BAY REGION WITH 3
TO 6 INCHES OF SNOW. AS YOU MOVE FURTHER NW FROM THIS AREA AMTS DROP
OFF QUICKLY...WITH 1-3" FROM SEACOAST NH NE THROUGH THE PORTLAND
AREA...THE CAPITAL REGION...AND INTO SRN SOMERSET COUNTY. EXPECT AN
INCH OR LESS ACROSS THE REST OF NH AND INTERIOR WRN ME. THE BULK OF
THE SNOW LOOKS TO FALL BETWEEN 06Z AND 12Z. IN THE ADVISORY AREA IT
MAY LINGER UNTIL ABOUT 15Z...SO COULD SEE A QUICK 4-6" OF SNOW HERE
DURING PRE-DAWN AND INTO THE MORNING COMMUTE. TEMPS WILL DROP OFF A
BIT THIS EVENING...MORE SO IN THE ERN AND NRN ZONES WHERE LESS
CLOUDS AND A PERIOD WITHOUT ANY REAL BL FLOW WILL ALLOW SOME RAD
COOLING. BUT TEMPS HERE WILL STALL AND SHOULD BEGIN TO RISE NEAR THE
COAST AFTER MIDNIGHT.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
SOME LIGHT SNOW MAY LINGER OUTSIDE THE ADV AREA FOR THE EARLY
MORNING...BUT SHOULD BE CLOSE TO OVER BY 12Z...WITH THE EXCEPTION
OF THE ADVISED MID-COAST AREA...WHERE SNOW WILL LINGER THRU ABOUT
14-15Z. MODELS INDICATE RAPID CLEARING FROM W-E BEHIND THIS SYSTEM
AS W WINDS DOWNSLOPE AND DRIER AIR MOVES IN. WITH THE SUN AND THE
DOWNSLOPE...WILL SEE TEMPS RISE IN THE UPPER 20S TO LOWER 30S ON THE
COASTAL...AND INTO THE LOW TO MID 20S IN THE MTNS AND FOOTHILLS.
THE WINDS DIE OFF AROUND SUNSET WITH MAINLY CLEAR SKIES AND LIGHT
WINDS SHOULD SEE SOME GOOD RAD COOLING...BUT WITH WARMER AIR
ALOFT...WILL NOT BE AS COLD AS MON MORNING WITH LOWS SINGLE ABV ZERO
NEAR THE COAST...AND SINGLE DIGITS BELOW ZERO INLAND.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
LOW PRESSURE WILL MOVE
SOUTH OF THE REGION DURING THURSDAY. AT THIS POINT IT LOOKS LIKE
CLOUDS FROM THIS SYSTEM WILL CROSS THE AREA BUT THE PRECIPITATION
SHIELD WILL STAY SOUTH OF THE AREA. THE GFS WOULD GIVE THE
POSSIBILITY OF A FEW FLURRIES BUT THE EURO KEEPS ALL PRECIPITATION
SOUTH. REINFORCING COLD COMES IN BEHIND THIS SYSTEM FOR FRIDAY AND
SATURDAY AS HIGH PRESSURE BUILD OVER THE REGION.
FOR SUNDAY...AS THE HIGH MOVES EAST OF THE AREA CLOUDS WILL INCREASE
AND TEMPERATURES WILL MODERATE SOME. A WEAK OVERRUNNING SETUP FORMS
SUNDAY NIGHT THAT COULD PRODUCE A PERIOD OF SNOW. ANOTHER WEAK AREA
OF HIGH PRESSURE BRIEFLY BUILDS IN FOR MONDAY.
MODELS AGREE ON BRINGING ANOTHER AREA OF LOW PRESSURE OVER THE
AREA LATE MONDAY NIGHT AND TUESDAY. WITH MODERATING
TEMPERATURES...PRECIPITATION TYPE COULD BECOME A CHALLENGE BY LATE
TUESDAY OVER SOUTHERN AREAS.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
SHORT TERM...CONDITIONS DETERIORATE TO MVFR LATE THIS EVENING AND
EVENTUALLY IFR IN -SN AT ALL BUT KLEB/KHIE WHERE IT WILL LKLY STAY
MAINLY MVFR IN -SHSN. CONDS WILL IMPROVE QUICKLY TO VFR DURING WED
MORNING BEHIND THIS SYSTEM...WHICH WILL PERSIST INTO WED NIGHT.
LONG TERM...AN AREA OF MVFR CLOUDS WILL BE POSSIBLE THURSDAY AS
LOW PRESSURE MOVES SOUTH OF THE REGION. HIGH PRESSURE WILL RESULT
IN MOSTLY VFR CONDITIONS FRIDAY AND SATURDAY. A WARM FRONT COULD
RESULT IN MVFR CONDITIONS ON SUNDAY AND SUNDAY NIGHT. A PERIOD OF
SNOW IS POSSIBLE SUNDAY NIGHT.
&&
.MARINE...
SHORT TERM...WILL SEE AN INCREASE IN SW FLOW...WHICH COULD PRODUCE
A FEW GUSTS TO NEAR 25 KT LATE TONIGHT...BUT WILL HOLD OFF THE SCA
FOR NOW. BETTER CHC FOR SCA WILL BE IN THE W FLOW BEHIND THE
SYSTEM FROM LATE WED MORNING INTO WED EVE.
LONG TERM...
LOW PRESSURE WILL PASS SOUTH OF THE WATERS THURSDAY. HIGH PRESSURE
WILL BUILD OVER THE WATERS FRIDAY AND SATURDAY FOLLOWED BY THE
APPROACH OF A WARM FRONT SUNDAY. WINDS AND WAVES ARE EXPECTED TO
REMAIN BELOW SCA LEVELS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO NOON EST
WEDNESDAY FOR MEZ022-026>028.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 11 PM EST WEDNESDAY FOR
ANZ151-153.
SMALL CRAFT ADVISORY UNTIL 11 PM EST WEDNESDAY FOR ANZ150-152-
154.
&&
$$
NEAR TERM UPDATE...EKSTER
NEAR TERM...CEMPA
SHORT TERM...CEMPA
LONG TERM...LULOFS
AREA FORECAST DISCUSSION
NWS GRAY ME
618 PM EST TUE FEB 24 2015
.SYNOPSIS...
WEAK LOW PRESSURE WILL PASS EAST OF THE AREA LATE TONIGHT AND
WEDNESDAY....AND WILL PRODUCE A PERIOD OF SNOW...ENDING BY
WEDNESDAY AFTERNOON. HIGH PRESSURE FOLLOWS THIS SYSTEM FOR
THURSDAY INTO THE START OF NEXT WEEKEND. THE NEXT CHANCE FOR
PRECIPITATION WILL COME AS HIGH PRESSURE RETREATS LATE IN THE
WEEKEND OR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
615 PM UPDATE...HAVE UPDATED THE NEAR TERM FORECAST BASED ON
LATEST TRENDS IN OBSERVATIONAL DATA AS WELL AS NEW MESOSCALE
MODEL DATA. IT WILL BE INTERESTING TO SEE HOW THE SNOWFALL PANS
OUT LATER TONIGHT. 18Z MODEL RUNS PRETTY MUCH STATUS QUO.
HOWEVER...LATEST FEW RUNS OF THE RAP AND HRRR KEEP MOST OF IT
OFFSHORE. HOPEFULLY THE TWO CAMPS WILL MERGE OVER THE NEXT COUPLE
OF HOURS.
PREVIOUSLY...
WEAK WAVES IN THE SRN AND NRN STREAM PASS TO OUR NW AND SE LATE
TONIGHT /BEFORE EVENTUALLY PHASING TO OUR EAST ON WED/ AND WILL
BRING A PERIOD OF LIGHT OR SHSN TO MOVE OVER THE REGION...MAINLY
AFTER MIDNIGHT. MODELS ARE IN GOOD AGREEMENT THAT AS THE SYSTEMS
INTERACT LATE TONIGHT WE WILL START TO SEE SOME MID LVL
FRONTOGENESIS FORM JUST OFFSHORE. THIS WILL LKLY FORM A BAND OF SNOW
OFF THE COAST...WHICH WILL GRAZE COASTAL AREAS E OF KPWM AND WILL
IMPACT THE MID COAST AND ESPECIALLY THE PENOBSCOT BAY REGION WITH 3
TO 6 INCHES OF SNOW. AS YOU MOVE FURTHER NW FROM THIS AREA AMTS DROP
OFF QUICKLY...WITH 1-3" FROM SEACOAST NH NE THROUGH THE PORTLAND
AREA...THE CAPITAL REGION...AND INTO SRN SOMERSET COUNTY. EXPECT AN
INCH OR LESS ACROSS THE REST OF NH AND INTERIOR WRN ME. THE BULK OF
THE SNOW LOOKS TO FALL BETWEEN 06Z AND 12Z. IN THE ADVISORY AREA IT
MAY LINGER UNTIL ABOUT 15Z...SO COULD SEE A QUICK 4-6" OF SNOW HERE
DURING PRE-DAWN AND INTO THE MORNING COMMUTE. TEMPS WILL DROP OFF A
BIT THIS EVENING...MORE SO IN THE ERN AND NRN ZONES WHERE LESS
CLOUDS AND A PERIOD WITHOUT ANY REAL BL FLOW WILL ALLOW SOME RAD
COOLING. BUT TEMPS HERE WILL STALL AND SHOULD BEGIN TO RISE NEAR THE
COAST AFTER MIDNIGHT.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
SOME LIGHT SNOW MAY LINGER OUTSIDE THE ADV AREA FOR THE EARLY
MORNING...BUT SHOULD BE CLOSE TO OVER BY 12Z...WITH THE EXCEPTION
OF THE ADVISED MID-COAST AREA...WHERE SNOW WILL LINGER THRU ABOUT
14-15Z. MODELS INDICATE RAPID CLEARING FROM W-E BEHIND THIS SYSTEM
AS W WINDS DOWNSLOPE AND DRIER AIR MOVES IN. WITH THE SUN AND THE
DOWNSLOPE...WILL SEE TEMPS RISE IN THE UPPER 20S TO LOWER 30S ON THE
COASTAL...AND INTO THE LOW TO MID 20S IN THE MTNS AND FOOTHILLS.
THE WINDS DIE OFF AROUND SUNSET WITH MAINLY CLEAR SKIES AND LIGHT
WINDS SHOULD SEE SOME GOOD RAD COOLING...BUT WITH WARMER AIR
ALOFT...WILL NOT BE AS COLD AS MON MORNING WITH LOWS SINGLE ABV ZERO
NEAR THE COAST...AND SINGLE DIGITS BELOW ZERO INLAND.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
LOW PRESSURE WILL MOVE
SOUTH OF THE REGION DURING THURSDAY. AT THIS POINT IT LOOKS LIKE
CLOUDS FROM THIS SYSTEM WILL CROSS THE AREA BUT THE PRECIPITATION
SHIELD WILL STAY SOUTH OF THE AREA. THE GFS WOULD GIVE THE
POSSIBILITY OF A FEW FLURRIES BUT THE EURO KEEPS ALL PRECIPITATION
SOUTH. REINFORCING COLD COMES IN BEHIND THIS SYSTEM FOR FRIDAY AND
SATURDAY AS HIGH PRESSURE BUILD OVER THE REGION.
FOR SUNDAY...AS THE HIGH MOVES EAST OF THE AREA CLOUDS WILL INCREASE
AND TEMPERATURES WILL MODERATE SOME. A WEAK OVERRUNNING SETUP FORMS
SUNDAY NIGHT THAT COULD PRODUCE A PERIOD OF SNOW. ANOTHER WEAK AREA
OF HIGH PRESSURE BRIEFLY BUILDS IN FOR MONDAY.
MODELS AGREE ON BRINGING ANOTHER AREA OF LOW PRESSURE OVER THE
AREA LATE MONDAY NIGHT AND TUESDAY. WITH MODERATING
TEMPERATURES...PRECIPITATION TYPE COULD BECOME A CHALLENGE BY LATE
TUESDAY OVER SOUTHERN AREAS.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
SHORT TERM...CONDITIONS DETERIORATE TO MVFR LATE THIS EVENING AND
EVENTUALLY IFR IN -SN AT ALL BUT KLEB/KHIE WHERE IT WILL LKLY STAY
MAINLY MVFR IN -SHSN. CONDS WILL IMPROVE QUICKLY TO VFR DURING WED
MORNING BEHIND THIS SYSTEM...WHICH WILL PERSIST INTO WED NIGHT.
LONG TERM...AN AREA OF MVFR CLOUDS WILL BE POSSIBLE THURSDAY AS
LOW PRESSURE MOVES SOUTH OF THE REGION. HIGH PRESSURE WILL RESULT
IN MOSTLY VFR CONDITIONS FRIDAY AND SATURDAY. A WARM FRONT COULD
RESULT IN MVFR CONDITIONS ON SUNDAY AND SUNDAY NIGHT. A PERIOD OF
SNOW IS POSSIBLE SUNDAY NIGHT.
&&
.MARINE...
SHORT TERM...WILL SEE AN INCREASE IN SW FLOW...WHICH COULD PRODUCE
A FEW GUSTS TO NEAR 25 KT LATE TONIGHT...BUT WILL HOLD OFF THE SCA
FOR NOW. BETTER CHC FOR SCA WILL BE IN THE W FLOW BEHIND THE
SYSTEM FROM LATE WED MORNING INTO WED EVE.
LONG TERM...
LOW PRESSURE WILL PASS SOUTH OF THE WATERS THURSDAY. HIGH PRESSURE
WILL BUILD OVER THE WATERS FRIDAY AND SATURDAY FOLLOWED BY THE
APPROACH OF A WARM FRONT SUNDAY. WINDS AND WAVES ARE EXPECTED TO
REMAIN BELOW SCA LEVELS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO NOON EST
WEDNESDAY FOR MEZ022-026>028.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 11 PM EST WEDNESDAY FOR
ANZ151-153.
SMALL CRAFT ADVISORY UNTIL 11 PM EST WEDNESDAY FOR ANZ150-152-
154.
&&
$$
NEAR TERM UPDATE...EKSTER
NEAR TERM...CEMPA
SHORT TERM...CEMPA
LONG TERM...LULOFS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
344 PM EST MON FEB 23 2015
.SYNOPSIS...
COLD HIGH PRESSURE WILL BUILD IN FROM THE WEST TONIGHT THEN SLIDE
SOUTH OF THE REGION ON TUESDAY. A TROUGH OF LOW PRESSURE WILL
APPROACH TUESDAY NIGHT. LOW PRESSURE WILL DEVELOP SOUTH OF THE AREA
EARLY WEDNESDAY AND TRACK INTO THE MARITIMES WEDNESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TUESDAY/...
THE MAIN CHALLENGES THIS TERM WILL BE STREAMERS OFF THE ST.
LAWRENCE, WIND CHILLS AND OF COURSE TEMPERATURES.
LATEST VISIBLE SATELLITE IMAGERY SHOWED CLOUDS MOVING E OFF THE ST
LAWRENCE. LLVL CONVERGENCE SHOWING UP ON THE SURFACE ANALYSIS
ACROSS FAR NORTHERN MAINE(THE CROWN MOST PARTICULARLY. PERIODS OF
LIGHT SNOW FOR NW AND NE AROOSTOOK COUNTY COULD BRING AN INCH OF
SNOW BY THIS EVENING AND THEN WINDS BEGIN TO LET UP. MODEL SOUNDINGS
SUPPORT DEEP MOISTURE THROUGH 800MBS W/SOME WEAK FORCING ALOFT.
DECIDED TO BOOST POPS UP ACROSS THE FAR NORTHERN AREAS(60-80%) TO
ACCOUNT FOR THE SNOW. THE RAP/NAM12 AND HRRR MESOSCALE MODELS
WERE DOING WELL W/THIS SETUP. AREAS OF BLOWING SNOW A FACTOR INTO
THE EVENING AND WILL CONTINUE THAT WORDING IN THE FORECAST THROUGH
9 PM. HISTORICALLY, CLOUDS AND STREAMERS BREAK UP AS THE WINDS
SHIFT MORE TO THE WEST AND THE AIRMASS DRIES OUT. THIS IS SHOWN TO
BE THE CASE LATER THIS EVENING. FURTHER S, BASICALLY CLEAR SKIES
W/SOME SCT CLOUDS FROM TIME TO TIME. THIS WILL LEAD TO SOME VERY
COLD IF NOT BITTERLY COLD TEMPERATURES OVERNIGHT INTO TUESDAY
MORNING. WE ARE TALKING 15 TO 25 BELOW ACROSS THE NORTH AND WEST
AND PERHAPS 30 BELOW IN THE SHELTERED AREAS. CENTRAL AND DOWNEAST
WILL 10 TO 15 BELOW EVEN TO THE COAST. DANGEROUS WIND CHILLS ARE
ON THE DOCKET THROUGH EARLY TUESDAY APPROACHING WARNING
CRITERIA(-35F) ACROSS THE NORTHERN AND WESTERN AREAS. ATTM,
DECIDED TO STAY W/WIND CHILL ADVISORIES AS THE WINDOW LOOKS TO BE
SHORT(<3 HRS) FOR WIND CHILLS TO HIT <-35F AND WINDS ARE FORECAST
TO DROP OFF BELOW 10 MPH.
TUESDAY WILL START OUT SUNNY AND VERY COLD W/HIGH PRES RIDGING
INTO THE REGION. THE RIDGE AXIS IF FORECAST TO SLIDE THROUGH THE
REGION QUICKLY DURING THE DAY W/CLOUDS ON THE INCREASE BY THE
AFTERNOON. DAYTIME TEMPERATURES ACROSS THE NORTHERN 1/2 OF THE CWA
IN THE SINGLE NUMBER WHILE CENTRAL AND DOWNEAST WILL SEE 10 TO 15
AT BEST AND THE WARMER TEMPERATURES TOWARD THE COAST.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
A TROUGH OF LOW PRESSURE WILL APPROACH FROM THE GREAT LAKES TUESDAY
NIGHT. A SMALL AREA OF LOW PRESSURE WILL DEVELOP ALONG THE
SOUTHEASTERN EDGE OF THE TROUGH, OFF THE SOUTHERN NEW ENGLAND COAST,
LATE TUESDAY NIGHT. THE FORECAST CHALLENGE WILL BE IN DETERMINING
HOW QUICKLY THIS LOW DEVELOPS AND HOW CLOSE THE LOW WILL TRACK TO
OUR REGION ON WEDNESDAY. LATEST FORECAST GUIDANCE CARRIES THE LOW
INTO THE GULF OF MAINE WEDNESDAY MORNING SPREADING SNOW ACROSS
DOWNEAST AREAS VERY EARLY WEDNESDAY MORNING THEN ON UP ACROSS EAST
CENTRAL AND NORTHEASTERN AREAS LATER WEDNESDAY MORNING. THIS IS A
SMALL, FAST MOVING LOW AND APPEARS WILL NOT BE IN THE AREA LONG
ENOUGH TO PRODUCE HEAVY SNOW ACCUMULATIONS. A LIGHT TO MODERATE
SNOWFALL OF 3 TO 5 INCHES CURRENTLY APPEARS MOST LIKELY FROM
DOWNEAST AREAS NORTHWARD INTO EASTERN AREAS OF NORTHERN MAINE
THROUGH WEDNESDAY MIDDAY BEFORE THE LOW LIFTS OUT. THE NAM...GFS
AND ECMWF ALL OFFER SIMILAR SOLUTIONS AND HAVE BEEN CONSISTENT
WITH PREVIOUS RUNS SHOWING JUST A QUICK SNOWFALL OF MODERATE
INTENSITY ACROSS EASTERN AREAS WITH THIS SYSTEM. THE LOW WILL
CONTINUE TO INTENSIFY WEDNESDAY AFTERNOON BUT WILL BE QUICK TO
LIFT NORTHEAST AND AWAY THROUGH THE MARITIMES AS DRY AND BREEZY
WEATHER FOLLOWS. SNOW SHOULD TAPER OFF LATE WEDNESDAY MORNING
DOWNEAST AND WEDNESDAY AFTERNOON ACROSS THE NORTHEAST. HIGH
PRESSURE WILL THEN BRING DRY AND COLD CONDITIONS WEDNESDAY NIGHT
INTO THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A LARGE AREA OF HIGH PRESSURE PUSHING INTO THE EAST WILL MAINTAIN
DRY WEATHER THURSDAY NIGHT THROUGH THE COMING WEEKEND. TEMPS AHEAD
OF THE HIGH WILL BE WELL BELOW NORMAL INTO SATURDAY, THEN WARM UP
CLOSER TO NORMAL LATE IN THE WEEKEND IN THE RETURN FLOW BEHIND THE
HIGH ON SUNDAY. CLOUDS WILL INCREASE ON SUNDAY AND SOME SNOW IS
POSSIBLE SUNDAY NIGHT INTO MONDAY AS A TROUGH AND WEAK FRONTAL
SYSTEM PUSH IN FROM THE WEST. AT THIS TIME THE SYSTEM SUNDAY NIGHT
INTO MONDAY LOOKS LIKE A PROGRESSIVE OPEN WAVE WITH ONLY LIGHT TO
MODERATE SNOW EXPECTED. DRIER CONDITIONS SHOULD RETURN BEHIND A COLD
FRONT LATER MONDAY INTO MONDAY NIGHT.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
NEAR TERM: MVFR W/IFR VSBYS THROUGH EARLY EVENING ACROSS THE
NORTHERN TERMINALS(NORTH OF KHUL) DUE TO THE STREAMERS OFF THE ST.
LAWRENCE. FURTHER SOUTH, GENERALLY VFR. CLOUDS AND LIGHT SNOW
ACROSS THE NORTH WILL END LATER THIS EVENING AS WINDS DROP OFF
LEADING TO VFR. IT LOOKS LIKE VFR FOR THE ENTIRE AVIATION SECTOR
FOR TUESDAY.
SHORT TERM: VFR CONDITIONS TUESDAY NIGHT WILL LOWER TO MVFR THEN
IFR VERY LATE AT NIGHT. IFR CONDITIONS IN SNOW ARE EXPECTED
WEDNESDAY MORNING. CONDITIONS MAY IMPROVE TO VFR DOWNEAST
WEDNESDAY AFTERNOON AND MVFR ACROSS THE NORTH WEDNESDAY AFTERNOON.
MAINLY VFR CONDITIONS ARE EXPECTED WEDNESDAY NIGHT AND THURSDAY
WITH THE POSSIBLE EXCEPTION OF SOME MVFR CONDITIONS IN THE ST JOHN
VALLEY. VFR CONDITIONS ARE THEN EXPECTED THURSDAY NIGHT THROUGH
SATURDAY.
&&
.MARINE...
NEAR TERM: WINDS ARE NOW HITTING GALE FORCE(35 KTS) ESPECIALLY
OVER THE OUTER ZONES AS THE CAA IS HITTING IN EARNEST. WINDS WILL
INCREASE FOR A WHILE THIS EVENING W/GUSTS TO 40 KTS. THE NAM12 WAS
DOING WELL W/THE CURRENT SETUP. WINDS WILL START DROPPING OFF
LATER TONIGHT AS HIGH PRES TO THE SW RIDGES EASTWARD. GALE WARNING
WILL REMAIN THROUGH TUESDAY MORNING. EVENING CREW CAN ASSESS THIS
FURTHER W/THE LATER GUIDANCE. HEAVY FREEZING SPRAY EXPECTED
TONIGHT INTO EARLY TUESDAY THE WARNING IS UP FOR HEAVY ICING
POTENTIAL. SEAS ARE COMING UP BUT WERE SLOWER TO RESPOND. SEAS
SHOULD TOP OUT AROUND 8 FT OVER THE OUTER ZONES THIS EVENING AND
THEN BEGIN TO SUBSIDE LATER TONIGHT AS WINDS DROP OFF.
SHORT TERM: AN SCA MAY BE NEEDED LATE TUESDAY NIGHT THROUGH
WEDNESDAY AS LOW PRESSURE LIFTS ACROSS THE WATERS. HIGH PRESSURE
BUILDING OVER THE AREA SHOULD BRING MAINLY RELATIVELY LIGHT WINDS
LATE THIS WEEKEND INTO THE COMING WEEKEND.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WIND CHILL ADVISORY UNTIL 10 AM EST TUESDAY FOR MEZ001>006-010-
011-031-032.
WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY
FOR MEZ015>017-029-030.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST TUESDAY FOR
ANZ050>052.
GALE WARNING UNTIL 4 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...BLOOMER
LONG TERM...BLOOMER
AVIATION...HEWITT/BLOOMER
MARINE...HEWITT/BLOOMER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1225 PM EST MON FEB 23 2015
.SYNOPSIS...
AN ARCTIC FRONT WILL CROSS THE AREA THIS AFTERNOON. HIGH PRESSURE
WILL BUILD ACROSS NORTHERN NEW ENGLAND TONIGHT AND WILL MOVE EAST
TUESDAY. DEVELOPING LOW PRESSURE FROM THE WEST WILL CROSS THE AREA
WEDNESDAY THEN MOVE TOWARD THE NORTHERN MARITIMES WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
1215 PM UPDATE...STREAMER BANDS CONTINUE OFF THE ST. LAWRENCE
MOVING ACROSS THE CROWN OF MAINE. THE MOST PROMINENT BAND WAS
ACROSS THE ST. JOHN VALLEY UP AROUND THE FRENCHVILLE-MADAWASKA
REGION. THE LATEST RUN OF THE RAP MODEL AND HRRR CONTINUE TO
DEPICT SOME BANDS HANGING ON INTO THE AFTERNOON ACROSS NORTHERN
MAINE AND SLIDING SE IN THE CARIBOU-PRESQUE ISLE REGION. SNOW
RATIOS W/THESE BANDS ARE HIGH(20-25:1) YIELDING CLOSE TO AN INCH
IN THE HEAVIER BANDS. THE BANDS SHOULD BEGIN TO WEAKEN THIS
EVENING AS WINDS START SETTLING DOWN AND THE DIRECTION SHIFTS
MORE TO A WNW DIRECTION SHUTTING DOWN THE TRAJECTORY FROM THE ST.
LAWRENCE. AREAS OF BLOWING AND DRIFTING SNOW CONTINUE INTO THE
EVENING.
DECIDED TO KEEP THE WIND CHILL HEADLINES AS THEY ARE FOR NOW.
FOR TONIGHT...THE ARCTIC HIGH WILL BUILD INTO NEW ENGLAND OVERNIGHT.
TEMPERATURES WILL PLUMMET THROUGH THE EVENING, WITH LOWS -15F TO -25F
ACROSS THE NORTHERN HALF OF OUR FORECAST AREA. DOWNEAST AREAS WILL
EVEN DROP BELOW ZERO, WITH LOWS OF -5F TO -15F. WINDS WILL
GRADUALLY ABATE LATER TONIGHT IN RESPONSE TO THE WEAKENING
PRESSURE GRADIENT UNDER THE RIDGE, ESPECIALLY OVER FAR WESTERN
LOCATIONS. THEREFORE, IN SPITE OF THE VERY COLD AIR TEMPERATURES,
THE WIND CHILL ADVISORY STILL LOOKS APPLICABLE, AS OPPOSED TO A
WIND CHILL WARNING.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
THE CORE OF BITTERLY COLD ARCTIC AIR WILL BE MOVG E OF THE FA TUE
MORN. AFT A VERY COLD START TO THE DAY...HI TEMPS SHOULD RECOVER
INTO THE SINGLE DIGITS BY MID TO LATE AFTN...WITH DOWNEAST AREAS
RECOVERING INTO THE TEENS BY ERLY EVE AS SFC WINDS BECOME SRLY
COMPONENT BEHIND DEPARTING SFC HI PRES MOVG E TOWARD THE OPEN
ATLC. THIS RETURN FLOW WILL BRING INCREASING CLDNSS FROM S TO N
ACROSS THE REGION TUE NGT...WITH LGT SN POSSIBLE TO PTNS OF THE FA
LATE TUE NGT.
MODELS THEN SHOW A S/WV COMPLEX MOVG E FROM CNTRL CAN AND THE
GREAT LKS TUE NGT INTO WED. THE SFC LOW WITH THIS SYSTEM IS XPCTD
TO REFORM FROM QB TUE NGT TO A SECONDARY LOW OVR THE S GULF OF ME
SW OF NOVA SCOTIA. THE SECONDARY LOW THEN GAINS MOMENTUM WED
AFTN...ABSORBING THE OLD PRIMARY LOW FROM QB BY WED EVE. A POCKET
OF SRLY LOW TO MID LVL WARM/MOISTURE ADVCN BEGINS TO DEVELOP OVR
ERN ME BEGINNING ERLY WED MORN JUST AHEAD OF THE DEVELOPING
SECONDARY...RESULTING IN MORE ORGANIZED SNFL CLIPPING ERN ME
MON MORN INTO ERLY AFTN BEFORE MOVING ENE INTO NB BY LATE WED
AFTN. MODELS VARY WITH REGARD TO THE QPF THAT MAY OCCUR OVR ERN
ME WITH THE TMG OF THIS EVENT...WITH THE 00Z DTMNSTC CANGEM AND
NAM MOST AGGRESSIVE AND THE GFS AND SPCLY ECMWF THE LEAST. WPC IS
LEANING MORE WITH THE GFS AND ECMWF MODELS ATTM...SO WE WEIGHT
THESE MODELS MORE WITH FCST 6HRLY QPF AND CORRESPONDING SNFL LATE
TUE NGT THRU WED. CONSIDERING THE UNCERTAINTY OF TMG OF
DEVELOPMENT OF THE SNFL SHIELD BEFORE THE SECONDARY MOVES AWAY
FROM THE REGION...WE KEPT SN TO LIQ RATIOS RELATIVELY CONSERVATIVE
AT 13.5 TO 1...WHICH RESULTS IN MAX TOTALS OF 3 TO 4 INCHES OVR SE
WASHINGTON COUNTY WHERE WE GO WITH CATEGORICAL POPS WITH LESSER
AMOUNTS AND POPS TO THE WNW.
SN SHOULD TAPER TO SN SHWRS FROM W TO E ACROSS THE REGION FROM
MID AFTN TO ERLY EVE...THEN END FROM S TO N OVRNGT WED...WITH
STRONGER LLVL COLD ADVCN XPCTD LATE WED NGT AND ERLY THU MORN WITH
A SECONDARY ARCTIC COLD FRONT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ANOTHER DEEP ARCTIC AIR MASS WILL FOLLOW THE SECONDARY COLD FRONT
ACROSS THE REGION FROM CNTRL CAN...WITH THIS AIR MASS NOT QUITE AS
COLD AS THE PRIOR AIR MASS AFFECTING THE FA ON TUE. UNDER FAIR
SKIES...HI TEMPS WILL BE WELL BLO SEASONAL AVGS FOR THE END OF FEB
THU AND FRI...WITH SOME RADIATIONAL COOLING POSSIBLE THU NGT AND
MSLY FRI NGT AS LARGE SPRAWLING SFC HI PRES RIDGES ENE INTO THE
REGION. WITH WEAK PRES GRAD FLOW INDICATED...THE BEST POTENTIAL
FOR COLDEST OVRNGT LOWS WILL BE ACROSS BROAD RVR VLYS OF NRN AND
CNTRL PTNS OF THE FA...WITH HILL TOP LCTNS LIKELY MAINTAINING A
LGT BREEZE KEEP OVRNGT LOWS NOT AS COLD. ANOTHER WV OF LOW PRES
TRACKING OFF THE SE U.S COAST WILL KEEP A LITTLE MORE PRES GRAD
AND PERHAPS HI CLD OVR THE DOWNEAST COAST BOTH NGTS LMTG THE
POTENTIAL OF VERY COLD LOW TEMPS.
SAT SHOULD CONT FAIR...BUT NOT AS COLD AS FCST AFTN 925 MB TEMPS
RISE FROM THE LOWER TO MID -20S TO -10S DEG C. WITH THE CNTR OF
STRONG SFC HI PRES TRACKING WELL S OF THE FA AS IT MOVES OFF THE
MID ATLC COAST...WINDS WILL LIKELY NOT HAVE MUCH CHC TO DECOUPLE
EVEN OVR VLY AREAS SAT NGT. SUN WILL BEGIN FAIR...THEN HI/MID
CLDNSS INCREASE LATER IN THE DAY AS A LARGE SHIELD OF LGT OVRRNG
SNFL APCHS FROM THE GREAT LKS AND QB PROV BY SUN EVE.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
NEAR TERM: MVFR CONDITIONS WITH OCCASIONAL IFR IN LIGHT SNOW AT
KHUL/KBHB WILL LINGER THROUGH 14Z OR SO TODAY. THEN CONDITIONS
WILL GRADUALLY IMPROVE AS A COLD FRONT CROSSES THE AREA AND ALLOWS
COLDER AND DRIER AIR TO SPREAD OVER THE REGION. WEST WINDS WILL
INCREASE TO 10-15KT WITH GUSTS TO 25KT POSSIBLE. THIS MAY RESULT
IN BLOWING SNOW WHICH COULD REDUCE VISIBILITY TO IFR AT TIMES
THROUGH THIS EVENING. OTHERWISE, PREVAILING VFR CONDITIONS ARE
EXPECTED FROM 15Z SOUTH/21Z NORTH WITH CLEARING SKIES.
SHORT TO LONG TERM: VFR XPCTD ALL TAF SITES TUE THRU TUE
EVE...WITH MVFR CLGS POSSIBLE LATE TUE NGT AND THEN MVFR OR IFR
VSBYS WITH LGT SNFL DURING THE DAY WED. AFTWRDS...MVFR CLGS CONT
ACROSS NRN TAF SITES WED NGT INTO THU MORN WHILE DOWNEAST SITES
BECOME VFR. ALL SITES THEN BECOME VFR THU AFTN AND CONT SO THRU
FRI.
&&
.MARINE...
NEAR TERM: A GALE WARNING REMAINS IN PLACE FOR TODAY AND TONIGHT.
A COLD FRONT WILL CROSS THE WATERS THIS MORNING, FOLLOWED BY WEST
TO NORTHWEST WINDS OF 20 TO 30 KT WITH GUSTS IN EXCESS OF 35 KT.
BITTERLY COLD TEMPERATURES AND THE STRONG WINDS WILL COMBINE TO
CREATE HEAVY FREEZING SPRAY, ESPECIALLY OVER THE OUTER WATERS, SO
THE FREEZING SPRAY WARNING REMAINS IN PLACE FOR LATER TODAY
THROUGH TONIGHT.
SHORT TO LONG TERM: SCA OR LESS CONDITIONS XPCTD THRU THIS PTN OF
THE FCST. HVY FZGSPY SHOULD BECOME MDT BY 12Z TUE...BECOMING LGT
BY LATE DAY AND THEN ENDING BY WED MORN AS COLD ADVCN DIMINISHES
OVR THE WATERS AND EVENTUALLY REVERSES TO WARM ADVCN. WENT ABV WW3
GUIDANCE FOR FCST WV HTS BY A FACTOR OF 1.15 OR SO...BASED ON BIAS
TRENDS OBSVD OVR THE PAST FEW WEEKS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WIND CHILL ADVISORY UNTIL 10 AM EST TUESDAY FOR MEZ001>006-010-
011-031-032.
WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY
FOR MEZ015>017-029-030.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST TUESDAY FOR
ANZ050>052.
GALE WARNING UNTIL 4 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
934 AM EST MON FEB 23 2015
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE AREA THIS MORNING. HIGH
PRESSURE WILL BUILD ACROSS NORTHERN NEW ENGLAND TONIGHT AND WILL
MOVE EAST TUESDAY. DEVELOPING LOW PRESSURE FROM THE WEST WILL
CROSS THE AREA WEDNESDAY THEN MOVE TOWARD THE NORTHERN MARITIMES
WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...LATEST RADAR SHOWED AREA OF SNOW AND SQUALLS NOW
IN NEW BRUNSWICK. BTV SNOW SQUALL PARAMETER AND 06Z NAM DID A FINE
JOB IN PICKING UP THE SNOW SQUALLS AS THEY MOVED THROUGH THE
REGION EARLIER THIS MORNING. THE HRRR MODEL AND THE RAP APPEAR TO
BE IN STEP W/TEH CURRENT SET PER THE RADAR IMAGERY. A FEW AREAS OF
SNOW STILL OCCURRING ACROSS THE REGION. ONE WAS ACROSS AR NORTHERN
MAINE NEAR THE FRENCHVILLE REGION COMING OFF ST. LAWRENCE
RIVER(STREAMER). THE OTHER AREA WAS MOVING OFF THE MT. KATAHDIN
REGION MOVING ACROSS SE AROOSTOOK COUNTY AND NORTHERN WASHINGTON
COUNTY. ADDED A 1/2 INCH OF NEW SNOW TO ACCOUNT FOR THESE AREAS OF
SNOW. VISIBLE SATELLITE IMAGERY SHOWED PLENTY OF SUNSHINE W/
SCATTERED STRATOCUMULUS. THE SUN COMBINED W/THE CAA TAKING PLACE
AIDING IN THE INCREASED WINDS. ADDED AREAS OF BLOWING SNOW TO THE
FORECAST FOR THIS AFTERNOON. WILL ADD BLOWING SNOW TO THE WSW
COMBINED W/THE WIND CHILL ADVISORY NW WINDS 15-25 MPH SUSTAINED
W/GUSTS TO 35 MPH EXPECTED.
PREVIOUS DISCUSSION...HIGH TEMPERATURES WILL BE EARLY THIS
MORNING, ESPECIALLY IN THE NORTH, THEN TEMPERATURES WILL FALL
THROUGH MUCH OF THE DAY UNDER BRISK WEST WINDS. WIND CHILLS WILL
QUICKLY DROP TO -15F TO -30F THIS AFTERNOON AND EVENING, SO HAVE
CONTINUED WITH THE WIND CHILL ADVISORY FOR OUR ENTIRE FORECAST
AREA. MUCH OF THE MODEL GUIDANCE CONTINUES TO INDICATE THE
POTENTIAL FOR SNOW SQUALLS AND/OR STREAMERS COMING OFF THE SAINT
LAWRENCE OVER FAR NORTHERN AROOSTOOK COUNTY THROUGH MUCH OF THE
DAY. AREAS OF BLOWING AND DRIFTING SNOW ARE ALSO A CONCERN ACROSS
ALL OF NORTHERN AND CENTRAL MAINE, AS THE GUSTY WINDS WILL EASILY
LOFT THE RECENTLY- FALLEN SNOW. ROAD CONDITIONS WILL LIKELY BE
POOR IN OPEN TERRAIN WITH SNOW DRIFTS AND VISIBILITY SHARPLY
REDUCED TO NEAR ZERO AT TIMES, ESPECIALLY ALONG NORTH-SOUTH ROADS
SUCH AS ROUTES 1 AND 11.
FOR TONIGHT...THE ARCTIC HIGH WILL BUILD INTO NEW ENGLAND OVERNIGHT.
TEMPERATURES WILL PLUMMET THROUGH THE EVENING, WITH LOWS -15F TO -25F
ACROSS THE NORTHERN HALF OF OUR FORECAST AREA. DOWNEAST AREAS WILL
EVEN DROP BELOW ZERO, WITH LOWS OF -5F TO -15F. WINDS WILL
GRADUALLY ABATE LATER TONIGHT IN RESPONSE TO THE WEAKENING
PRESSURE GRADIENT UNDER THE RIDGE, ESPECIALLY OVER FAR WESTERN
LOCATIONS. THEREFORE, IN SPITE OF THE VERY COLD AIR TEMPERATURES,
THE WIND CHILL ADVISORY STILL LOOKS APPLICABLE, AS OPPOSED TO A
WIND CHILL WARNING.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
THE CORE OF BITTERLY COLD ARCTIC AIR WILL BE MOVG E OF THE FA TUE
MORN. AFT A VERY COLD START TO THE DAY...HI TEMPS SHOULD RECOVER
INTO THE SINGLE DIGITS BY MID TO LATE AFTN...WITH DOWNEAST AREAS
RECOVERING INTO THE TEENS BY ERLY EVE AS SFC WINDS BECOME SRLY
COMPONENT BEHIND DEPARTING SFC HI PRES MOVG E TOWARD THE OPEN
ATLC. THIS RETURN FLOW WILL BRING INCREASING CLDNSS FROM S TO N
ACROSS THE REGION TUE NGT...WITH LGT SN POSSIBLE TO PTNS OF THE FA
LATE TUE NGT.
MODELS THEN SHOW A S/WV COMPLEX MOVG E FROM CNTRL CAN AND THE
GREAT LKS TUE NGT INTO WED. THE SFC LOW WITH THIS SYSTEM IS XPCTD
TO REFORM FROM QB TUE NGT TO A SECONDARY LOW OVR THE S GULF OF ME
SW OF NOVA SCOTIA. THE SECONDARY LOW THEN GAINS MOMENTUM WED
AFTN...ABSORBING THE OLD PRIMARY LOW FROM QB BY WED EVE. A POCKET
OF SRLY LOW TO MID LVL WARM/MOISTURE ADVCN BEGINS TO DEVELOP OVR
ERN ME BEGINNING ERLY WED MORN JUST AHEAD OF THE DEVELOPING
SECONDARY...RESULTING IN MORE ORGANIZED SNFL CLIPPING ERN ME
MON MORN INTO ERLY AFTN BEFORE MOVING ENE INTO NB BY LATE WED
AFTN. MODELS VARY WITH REGARD TO THE QPF THAT MAY OCCUR OVR ERN
ME WITH THE TMG OF THIS EVENT...WITH THE 00Z DTMNSTC CANGEM AND
NAM MOST AGGRESSIVE AND THE GFS AND SPCLY ECMWF THE LEAST. WPC IS
LEANING MORE WITH THE GFS AND ECMWF MODELS ATTM...SO WE WEIGHT
THESE MODELS MORE WITH FCST 6HRLY QPF AND CORRESPONDING SNFL LATE
TUE NGT THRU WED. CONSIDERING THE UNCERTAINTY OF TMG OF
DEVELOPMENT OF THE SNFL SHIELD BEFORE THE SECONDARY MOVES AWAY
FROM THE REGION...WE KEPT SN TO LIQ RATIOS RELATIVELY CONSERVATIVE
AT 13.5 TO 1...WHICH RESULTS IN MAX TOTALS OF 3 TO 4 INCHES OVR SE
WASHINGTON COUNTY WHERE WE GO WITH CATEGORICAL POPS WITH LESSER
AMOUNTS AND POPS TO THE WNW.
SN SHOULD TAPER TO SN SHWRS FROM W TO E ACROSS THE REGION FROM
MID AFTN TO ERLY EVE...THEN END FROM S TO N OVRNGT WED...WITH
STRONGER LLVL COLD ADVCN XPCTD LATE WED NGT AND ERLY THU MORN WITH
A SECONDARY ARCTIC COLD FRONT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ANOTHER DEEP ARCTIC AIR MASS WILL FOLLOW THE SECONDARY COLD FRONT
ACROSS THE REGION FROM CNTRL CAN...WITH THIS AIR MASS NOT QUITE AS
COLD AS THE PRIOR AIR MASS AFFECTING THE FA ON TUE. UNDER FAIR
SKIES...HI TEMPS WILL BE WELL BLO SEASONAL AVGS FOR THE END OF FEB
THU AND FRI...WITH SOME RADIATIONAL COOLING POSSIBLE THU NGT AND
MSLY FRI NGT AS LARGE SPRAWLING SFC HI PRES RIDGES ENE INTO THE
REGION. WITH WEAK PRES GRAD FLOW INDICATED...THE BEST POTENTIAL
FOR COLDEST OVRNGT LOWS WILL BE ACROSS BROAD RVR VLYS OF NRN AND
CNTRL PTNS OF THE FA...WITH HILL TOP LCTNS LIKELY MAINTAINING A
LGT BREEZE KEEP OVRNGT LOWS NOT AS COLD. ANOTHER WV OF LOW PRES
TRACKING OFF THE SE U.S COAST WILL KEEP A LITTLE MORE PRES GRAD
AND PERHAPS HI CLD OVR THE DOWNEAST COAST BOTH NGTS LMTG THE
POTENTIAL OF VERY COLD LOW TEMPS.
SAT SHOULD CONT FAIR...BUT NOT AS COLD AS FCST AFTN 925 MB TEMPS
RISE FROM THE LOWER TO MID -20S TO -10S DEG C. WITH THE CNTR OF
STRONG SFC HI PRES TRACKING WELL S OF THE FA AS IT MOVES OFF THE
MID ATLC COAST...WINDS WILL LIKELY NOT HAVE MUCH CHC TO DECOUPLE
EVEN OVR VLY AREAS SAT NGT. SUN WILL BEGIN FAIR...THEN HI/MID
CLDNSS INCREASE LATER IN THE DAY AS A LARGE SHIELD OF LGT OVRRNG
SNFL APCHS FROM THE GREAT LKS AND QB PROV BY SUN EVE.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
NEAR TERM: MVFR CONDITIONS WITH OCCASIONAL IFR IN LIGHT SNOW AT
KHUL/KBHB WILL LINGER THROUGH 14Z OR SO TODAY. THEN CONDITIONS
WILL GRADUALLY IMPROVE AS A COLD FRONT CROSSES THE AREA AND ALLOWS
COLDER AND DRIER AIR TO SPREAD OVER THE REGION. WEST WINDS WILL
INCREASE TO 10-15KT WITH GUSTS TO 25KT POSSIBLE. THIS MAY RESULT
IN BLOWING SNOW WHICH COULD REDUCE VISIBILITY TO IFR AT TIMES
THROUGH THIS EVENING. OTHERWISE, PREVAILING VFR CONDITIONS ARE
EXPECTED FROM 15Z SOUTH/21Z NORTH WITH CLEARING SKIES.
SHORT TO LONG TERM: VFR XPCTD ALL TAF SITES TUE THRU TUE
EVE...WITH MVFR CLGS POSSIBLE LATE TUE NGT AND THEN MVFR OR IFR
VSBYS WITH LGT SNFL DURING THE DAY WED. AFTWRDS...MVFR CLGS CONT
ACROSS NRN TAF SITES WED NGT INTO THU MORN WHILE DOWNEAST SITES
BECOME VFR. ALL SITES THEN BECOME VFR THU AFTN AND CONT SO THRU
FRI.
&&
.MARINE...
NEAR TERM: A GALE WARNING REMAINS IN PLACE FOR TODAY AND TONIGHT.
A COLD FRONT WILL CROSS THE WATERS THIS MORNING, FOLLOWED BY WEST
TO NORTHWEST WINDS OF 20 TO 30 KT WITH GUSTS IN EXCESS OF 35 KT.
BITTERLY COLD TEMPERATURES AND THE STRONG WINDS WILL COMBINE TO
CREATE HEAVY FREEZING SPRAY, ESPECIALLY OVER THE OUTER WATERS, SO
THE FREEZING SPRAY WARNING REMAINS IN PLACE FOR LATER TODAY
THROUGH TONIGHT.
SHORT TO LONG TERM: SCA OR LESS CONDITIONS XPCTD THRU THIS PTN OF
THE FCST. HVY FZGSPY SHOULD BECOME MDT BY 12Z TUE...BECOMING LGT
BY LATE DAY AND THEN ENDING BY WED MORN AS COLD ADVCN DIMINISHES
OVR THE WATERS AND EVENTUALLY REVERSES TO WARM ADVCN. WENT ABV WW3
GUIDANCE FOR FCST WV HTS BY A FACTOR OF 1.15 OR SO...BASED ON BIAS
TRENDS OBSVD OVR THE PAST FEW WEEKS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WIND CHILL ADVISORY FROM 3 PM THIS AFTERNOON TO 10 AM EST
TUESDAY FOR MEZ001>006-010-011-031-032.
WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY
FOR MEZ015>017-029-030.
MARINE...HEAVY FREEZING SPRAY WARNING FROM 3 PM THIS AFTERNOON TO 7 AM
EST TUESDAY FOR ANZ050>052.
GALE WARNING UNTIL 4 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HASTINGS/HEWITT
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS/HEWITT/VJN
MARINE...HASTINGS/HEWITT/VJN
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
411 AM EST MON FEB 23 2015
.SYNOPSIS...
A FRONTAL BOUNDARY STALLS ACROSS THE CAROLINA COAST TONIGHT AND
MONDAY AS A WEAK AREA OF LOW PRESSURE MOVES EAST ALONG IT. AN
ARCTIC COLD FRONT WILL PUSH ACROSS THE AREA MONDAY MORNING. HIGH
PRESSURE RETURNS THROUGH MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST RADAR TRENDS SUPPORT WHAT 00Z MODELS HAVE TRENDED
TOWARDS: A BAND OF PRECIP FORMING NORTH OF THE MAIN AXIS OF DEEPER
MOISTURE OVER NE NC. THUS...HAVE BUMPED POPS UP TO LIKELY FOR A
FEW HRS (MAINLY FROM 12-15Z) ACRS CENTRAL VA INCLUDING METRO RIC.
PTYPE INITIALLY LIGHT RAIN BUT SHOULD TRANSITION QUICKLY TO MAINLY
SNOW BY 12Z. THIS BAND EXPECTED TO SHIFT SE THROUGH THE LATER AM
HRS...AND ALLOW RAIN TO CHANGE TO SLEET/SNOW INTO HAMPTON ROADS
AND NE NC SOMETIME AROUND 15Z. LIGHT ACCUMULATIONS POSSIBLE...MAY
ISSUE AN SPS BUT NO ADSY AS AMOUNTS SHOULD BE WELL BELOW CRITERIA.
PREV DISC...
18Z/22 GFS AND RUC SUGGEST A LITTLE BETTER CHC FOR A PD OF LGT
PCPN OVR SRN VA/NE NC LT TNGT INTO MID/LT MRNG HRS MON. HAVE
ADJUSTED POPS UP ACRS SRN/SE VA AND NE NC. ADDED 30-50% CHC SN N
OF THE VA/NC BORDER TO ABT FVX-LFI/SRN PORTION OF ERN SHORE...W/
PSBL ACCUM LESS THAN 1 INCH. MIXED PTYPC PSBL ACRS NE NC...PTNTLLY
BECOMING SN BEFORE ENDING LT MON MRNG/EARLY AFTN. ANY PCPN WILL BE
ARRIVING W/ LO LVL CAA INCRSG AS NEXT CDFNT PUSHES THROUGH THE RGN.
TEMPS ONLY RISE A FEW DEGREES FROM 12Z READINGS THEN REMAIN
STEADY OR SLOWLY FALL BACK INTO THE 20S IN THE AFTRN AS THE NEXT
ARCTIC HIGH PRESSURE BUILDS INTO THE REGION ON GUSTY N-NW WINDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
MSTLY CLR TO PT CLDY SKIES MONDAY NIGHT AS RIDGE AXIS BUILDS OVER
THE FA. RECORD LOWS IN JEOPARDY AS WINDS WEST OF THE BAY DECOUPLE
ALLOWING FOR GOOD RADIATIONAL COOLING. WIND CHILL VALUES ALONG THE
COAST ARE EXPECTED TO REMAIN ABOVE ADVISORY CRITERIA. ONLY THING
THAT MIGHT PREVENT THE RECORDS FROM FALLING IS SOME MID / HIGH
LEVEL CLOUDS NOTED IN TSCTNS. LOWS 5-10 EASTERN SHORE...10-15
ELSEWHERE EXCEPT M-U TEENS SERN BEACH AREAS. SEE CLI SECTION BELOW
FOR TUES RECORD TMPS.
PT TO MSTLY SUNNY TUESDAY. COLD AS H85 TMPS ONLY SUPPORT HIGHS IN THE
U20S-M30S. MODELS SHOW WEAK AREA OF LOW PRESSURE (TROF) OFF THE SERN
COAST TUESDAY NIGHT. EXPECT THE SGNFCNT MOISTURE TO STAY ALONG OR
EAST OF THE CAROLINA COAST. WENT WITH A BIT MORE CLOUD COVERAGE OVER
THE EAST THUS PT TO MSTLY CLDY SKIES AS AN UPPER LEVEL TROF SWINGS
ACROSS THE NERN STATES. NOT AS COLD AS SW WINDS HOLD LOWS IN THE 20S.
THE LOW PULLS FURTHER EAST AND OFF THE COAST WED. MILDER UNDER PT TO
MSTLY SUNNY SKIES. WEST WINDS ALLOW TMPS TO WARM BACK INTO THE 40S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE LONG TERM WILL BRING SUBTLE CHANGES TO THE WEATHER. WHILE BELOW
NORMAL TEMPERATURES WILL CONTINUE...THE COLD WILL NOT BE AS BRUTAL
AS THE PAST WEEK. A SPLIT FLOW PATTERN WILL BRING A MORE ACTIVE
SOUTHERN STREAM WILL BRING LOW PRESSURE SYSTEMS PASSING TO THE SOUTH
OF THE AREA BUT WIDESPREAD PRECIPITATION IS NOT EXPECTED.
FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT MID WEEK...A LOW
PRESSURE SYSTEM MOVES OFF THE SOUTHEAST COAST WEDNESDAY NIGHT. PCPN
SHOULD GENERALLY BE TO THE SOUTH OF THE AREA. GUIDANCE HAS VARIOUS
CHANCES FOR PCPN SATURDAY THROUGH SUNDAY WITH RAIN OR SNOW SATURDAY
AND SATURDAY NIGHT AND RAIN SUNDAY. A COLD FRONT APPROACHES FROM THE
WEST LATE IN THE WEEKEND. KEPT POPS AT 30 PERCENT DURING THE
WEEKEND.
HIGH TEMPERATURES IN THE UPR 20S TO 30S THURSDAY AND FRIDAY WARM TO
THE UPR 40S AND 50S BY SUNDAY. LOWS WILL BE MAINLY IN THE
20S...WARMING TO THE MID 30S NEAR THE SE VA/NE NC COAST SUNDAY
MORNING.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
LIGHT FLOW IN BETWEEN STALLED BOUNDARY TO THE SOUTH AND HIGH
PRESSURE WELL OFF TO THE NW OF THE REGION HAS ALLOWED AREAS OF
DENSE FOG TO PERSIST NEAR THE COAST. EXPECT THIS TO CONTINUE
THROUGH ABOUT 08-09Z...WITH VSBYS IMPROVING THEREAFTER AS NNE
WINDS INCREASE. HOWEVER...WAVE OF LOW PRESSURE ALONG THAT BOUNDARY
TO THE SOUTH WILL BRING SOME INCREASE IN DEEPER MOISTURE AND A CHC
FOR RAIN CHANGING TO SNOW OR SNOW/SLEET MIX THROUGH THE MORNING
FROM NW TO SE SO THAT AFTER 15Z ALL AREAS ARE EXPERIENCING MAINLY
SNOW/SLEET. PRECIP SHOULD END AT KRIC AFTER 15 TO 16ZZ...BUT
PERSIST UNTIL AT LEAST 18Z AT KORF/KPHF/KECG. CIGS/VSBYS WILL
REMAIN IFR TO LOW END MVFR WITH THE PRECIP...THEN IMPROVE THROUGH
THE AFTN. WINDS WILL BECOME STRONG FROM THE NNE AFTER 12Z WITH
GUSTS TO 20 KT INLAND AND 25-30 KT NEAR THE COAST. WINDS DIMINISH
TONIGHT.
OUTLOOK...MAINLY DRY...COLD WITH VFR CONDITIONS EXPECTED TUE AND
WED. ANOTHER SYSTEM PASSES BY TO THE SOUTH WED NIGHT/THU AND MAY
BRING SOME SNOW TO MAINLY SE VA/NE NC SITES.
&&
.MARINE...
RAISED GALE WARNING FOR NC COASTAL WATERS...AS THERE LOOKS TO BE A
PERIOD OF 6-9 HRS OF GUSTS TO AT LEAST 35 KT THIS AFTN/EARLY
EVENING WHEN SFC LOW PUSHES ENE OFF THE NC COAST AND INTENSIFIES.
RAISED SEAS TO 7-10 FT IN THESE AREAS AS WAVEWATCH TYPICALLY WELL
UNDERDONE IN THIS NNE WIND PATTERN. STRONG SCA`S ELSEWHERE WITH
20-25 KT G30 KT. WILL LIKELY SEE A FEW GUSTS TO GALE FORCE BRIEFLY
LATER TODAY FOR SRN VA CSTL WATERS AND MOUTH OF BAY BUT DURATION
AND COVERAGE LOOKS TOO LOW ATTM TO RAISE GALES.
SEAS WILL BLD TO 5-8 FT ACRS REMAINDER OF CSTL WATERS AND WAVES WILL
BLD TO 3-5 FT IN THE CHES BAY. HI PRES BLDS ACRS THE REGION MON
NGT/TUE...THEN MOVES OFFSHR TUE AFTN/TUE NGT...AHEAD OF NEXT
ARCTIC FRONT. THIS FRONT WILL CROSS THE AREA ON WED...FOLLOWED BY
ANOTHER SURGE OF COLD AIR FOR THU AND FRI.
&&
.TIDES/COASTAL FLOODING...
LOW WATER ADVISORIES HAVE ENDED AS THE NEGATIVE ANOMALIES HAVE
DIMINISHED...BUT WATER LEVELS GENLY REMAIN BELOW ASTRONOMICAL
TIDES THROUGH MIDWEEK.
&&
.CLIMATE...
NORFOLK`S LOW TEMPERATURE OF 9 DEGREES ON FEB 20 WAS THE COLDEST
FOR SO LATE IN THE SEASON. THE MINUS 4 DEGREE READING AT SALISBURY
ON FEB 21ST IS NOW THE ALL TIME LOW FOR THE MONTH OF FEBRUARY.
THE CURRENT AVERAGE TEMPERATURES FOR THE MONTH OF FEBRUARY AT
BOTH RICHMOND AND NORFOLK PLACE THEM IN THE TOP 10 COLDEST. WITH
ADDITIONAL COLD TEMPERATURES EXPECTED NEXT WEEK...IT IS VERY
LIKELY THAT BOTH SITES WILL HAVE AVERAGE TEMPERATURES IN THE TOP
10 COLDEST FEBRUARYS ON RECORD...PERHAPS IN THE TOP 5 COLDEST.
RECORD LOW TEMPERATURES FOR TUESDAY 2/24:
RIC...11 IN 1914
ORF...16 IN 1947
SBY...10 IN 1934
ECG...19 IN 1947
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR
ANZ635>637.
SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR ANZ630>632-634-
650-652-654.
SMALL CRAFT ADVISORY UNTIL 4 AM EST TUESDAY FOR ANZ633.
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ638.
SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR ANZ656.
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR ANZ658.
&&
$$
SYNOPSIS...ALB/MPR
NEAR TERM...BMD/MPR
SHORT TERM...MPR
LONG TERM...LSA
AVIATION...LKB
MARINE...LKB
TIDES/COASTAL FLOODING...
CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
205 AM EST MON FEB 23 2015
.SYNOPSIS...
A FRONTAL BOUNDARY STALLS ACROSS THE CAROLINA COAST TONIGHT AND
MONDAY AS A WEAK AREA OF LOW PRESSURE MOVES EAST ALONG IT. AN
ARCTIC COLD FRONT WILL PUSH ACROSS THE AREA MONDAY MORNING. HIGH
PRESSURE RETURNS THROUGH MID WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
LOCALLY DENSE FOG HAS FORMED FM PORTIONS OF THE ERN SHORE TO CSTL
SECTIONS IN SE VA (AND OVR THE ADJACENT WTRS). HAVE COVERED THE
FOG W/ A SPECIAL WEATHER STATEMENT ON LAND...AND DENSE FOG
ADVISORY OVR THE WTRS (UNTIL ABT 09Z/23). OTRW...VRB CLDS ACRS THE
AREA WILL TEMPS CONTG A SLOW DROP THROUGH THE 30S/40S. SOME DRIER
AIR WILL BE SPREADING SLOWLY INTO THE RGN FM THE NW BY LT
TNGT...SO THE FOG IS XPCD TO DISSIPATE. LO TEMPS MNLY 30 TO 35F.
18Z/22 GFS AND RUC SUGGEST A LITTLE BETTER CHC FOR A PD OF LGT
PCPN OVR SRN VA/NE NC LT TNGT INTO MID/LT MRNG HRS MON. HAVE
ADJUSTED POPS UP ACRS SRN/SE VA AND NE NC. ADDED 30-50% CHC SN N
OF THE VA/NC BORDER TO ABT FVX-LFI/SRN PORTION OF ERN SHORE...W/
PSBL ACCUM LESS THAN 1 INCH. MIXED PTYPC PSBL ACRS NE NC...PTNTLLY
BECOMING SN BEFORE ENDING LT MON MRNG/EARLY AFTN. ANY PCPN WILL BE
ARRIVING W/ LO LVL CAA INCRSG AS NEXT CDFNT PUSHES THROUGH THE RGN.
TEMPS ONLY RISE A FEW DEGREES FROM 12Z READINGS THEN REMAIN
STEADY OR SLOWLY FALL BACK INTO THE 20S IN THE AFTRN AS THE NEXT
ARCTIC HIGH PRESSURE BUILDS INTO THE REGION ON GUSTY N-NW WINDS.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
MSTLY CLR TO PT CLDY SKIES MONDAY NIGHT AS RIDGE AXIS BUILDS OVER
THE FA. RECORD LOWS IN JEOPARDY AS WINDS WEST OF THE BAY DECOUPLE
ALLOWING FOR GOOD RADIATIONAL COOLING. WIND CHILL VALUES ALONG THE
COAST ARE EXPECTED TO REMAIN ABOVE ADVISORY CRITERIA. ONLY THING
THAT MIGHT PREVENT THE RECORDS FROM FALLING IS SOME MID / HIGH
LEVEL CLOUDS NOTED IN TSCTNS. LOWS 5-10 EASTERN SHORE...10-15
ELSEWHERE EXCEPT M-U TEENS SERN BEACH AREAS. SEE CLI SECTION BELOW
FOR TUES RECORD TMPS.
PT TO MSTLY SUNNY TUESDAY. COLD AS H85 TMPS ONLY SUPPORT HIGHS IN THE
U20S-M30S. MODELS SHOW WEAK AREA OF LOW PRESSURE (TROF) OFF THE SERN
COAST TUESDAY NIGHT. EXPECT THE SGNFCNT MOISTURE TO STAY ALONG OR
EAST OF THE CAROLINA COAST. WENT WITH A BIT MORE CLOUD COVERAGE OVER
THE EAST THUS PT TO MSTLY CLDY SKIES AS AN UPPER LEVEL TROF SWINGS
ACROSS THE NERN STATES. NOT AS COLD AS SW WINDS HOLD LOWS IN THE 20S.
THE LOW PULLS FURTHER EAST AND OFF THE COAST WED. MILDER UNDER PT TO
MSTLY SUNNY SKIES. WEST WINDS ALLOW TMPS TO WARM BACK INTO THE 40S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE LONG TERM WILL BRING SUBTLE CHANGES TO THE WEATHER. WHILE BELOW
NORMAL TEMPERATURES WILL CONTINUE...THE COLD WILL NOT BE AS BRUTAL
AS THE PAST WEEK. A SPLIT FLOW PATTERN WILL BRING A MORE ACTIVE
SOUTHERN STREAM WILL BRING LOW PRESSURE SYSTEMS PASSING TO THE SOUTH
OF THE AREA BUT WIDESPREAD PRECIPITATION IS NOT EXPECTED.
FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT MID WEEK...A LOW
PRESSURE SYSTEM MOVES OFF THE SOUTHEAST COAST WEDNESDAY NIGHT. PCPN
SHOULD GENERALLY BE TO THE SOUTH OF THE AREA. GUIDANCE HAS VARIOUS
CHANCES FOR PCPN SATURDAY THROUGH SUNDAY WITH RAIN OR SNOW SATURDAY
AND SATURDAY NIGHT AND RAIN SUNDAY. A COLD FRONT APPROACHES FROM THE
WEST LATE IN THE WEEKEND. KEPT POPS AT 30 PERCENT DURING THE
WEEKEND.
HIGH TEMPERATURES IN THE UPR 20S TO 30S THURSDAY AND FRIDAY WARM TO
THE UPR 40S AND 50S BY SUNDAY. LOWS WILL BE MAINLY IN THE
20S...WARMING TO THE MID 30S NEAR THE SE VA/NE NC COAST SUNDAY
MORNING.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
LIGHT FLOW IN BETWEEN STALLED BOUNDARY TO THE SOUTH AND HIGH
PRESSURE WELL OFF TO THE NW OF THE REGION HAS ALLOWED AREAS OF
DENSE FOG TO PERSIST NEAR THE COAST. EXPECT THIS TO CONTINUE
THROUGH ABOUT 08-09Z...WITH VSBYS IMPROVING THEREAFTER AS NNE
WINDS INCREASE. HOWEVER...WAVE OF LOW PRESSURE ALONG THAT BOUNDARY
TO THE SOUTH WILL BRING SOME INCREASE IN DEEPER MOISTURE AND A CHC
FOR RAIN CHANGING TO SNOW OR SNOW/SLEET MIX THROUGH THE MORNING
FROM NW TO SE SO THAT AFTER 15Z ALL AREAS ARE EXPERIENCING MAINLY
SNOW/SLEET. PRECIP SHOULD END AT KRIC AFTER 15 TO 16ZZ...BUT
PERSIST UNTIL AT LEAST 18Z AT KORF/KPHF/KECG. CIGS/VSBYS WILL
REMAIN IFR TO LOW END MVFR WITH THE PRECIP...THEN IMPROVE THROUGH
THE AFTN. WINDS WILL BECOME STRONG FROM THE NNE AFTER 12Z WITH
GUSTS TO 20 KT INLAND AND 25-30 KT NEAR THE COAST. WINDS DIMINISH
TONIGHT.
OUTLOOK...MAINLY DRY...COLD WITH VFR CONDITIONS EXPECTED TUE AND
WED. ANOTHER SYSTEM PASSES BY TO THE SOUTH WED NIGHT/THU AND MAY
BRING SOME SNOW TO MAINLY SE VA/NE NC SITES.
&&
.MARINE...
HAVE DECIDED TO ISSUE A SCA FOR THE ENTIRE WTRS STARTING LATE TNGT
AND LASTING THRU MON EVENG/MON NGT. THERE IS STILL POTENTIAL FOR
GALE GUSTS DURING LATE MON MORNG/AFTN TIMEFRAME AT THE MOUTH OF THE
BAY AND CSTL WTRS S OF CAPE CHARLES...DUE TO STRONGER PRESSURE
GRADIENT IN THIS AREA. BUT...FOR NOW WENT WITH A STRONG SCA IN THESE
ZNS...AND WILL LET MIDNGT SHIFT DECIDE WHETHER TO UPGRADE TO A GALE
WARNG BASED ON NEWER GUIDANCE. BASED ON 12Z/22 GUIDANCE...COLD
ADVECTION REMAINS DELAYED BEHIND FRONT...WHICH WAS PUSHING OFF THE
CST LATE THIS AFTN. THIS MEANS NORTHERLY WIND SURGE WON`T BEGIN
UNTIL LATE TNGT/EARLY MON MORNG. SURGE WILL CONTINUE THRU
MON...BEFORE WINDS DIMINISH MON NGT. SEAS WILL BLD TO 5-9 FT AND
WAVES WILL BLD TO 3-5 FT IN THE CHES BAY. HI PRES BLDS ACRS THE
REGION MON NGT/TUE...THEN MOVES OFFSHR TUE AFTN/TUE NGT...AHEAD OF
NEXT ARCTIC FRONT. THIS FRONT WILL CROSS THE AREA ON WED...FOLLOWED
BY ANOTHER SURGE OF COLD AIR FOR THU AND FRI.
&&
.TIDES/COASTAL FLOODING...
LOW WATER ADVISORIES HAVE ENDED AS THE NEGATIVE ANOMALIES HAVE
DIMINISHED...BUT WATER LEVELS GENLY REMAIN BELOW ASTRONOMICAL
TIDES THROUGH MIDWEEK.
&&
.CLIMATE...
NORFOLK`S LOW TEMPERATURE OF 9 DEGREES ON FEB 20 WAS THE COLDEST
FOR SO LATE IN THE SEASON. THE MINUS 4 DEGREE READING AT SALISBURY
ON FEB 21ST IS NOW THE ALL TIME LOW FOR THE MONTH OF FEBRUARY.
THE CURRENT AVERAGE TEMPERATURES FOR THE MONTH OF FEBRUARY AT
BOTH RICHMOND AND NORFOLK PLACE THEM IN THE TOP 10 COLDEST. WITH
ADDITIONAL COLD TEMPERATURES EXPECTED NEXT WEEK...IT IS VERY
LIKELY THAT BOTH SITES WILL HAVE AVERAGE TEMPERATURES IN THE TOP
10 COLDEST FEBRUARYS ON RECORD...PERHAPS IN THE TOP 5 COLDEST.
RECORD LOW TEMPERATURES FOR TUESDAY 2/24:
RIC...11 IN 1914
ORF...16 IN 1947
SBY...10 IN 1934
ECG...19 IN 1947
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR
ANZ635>638.
DENSE FOG ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR
ANZ631-632-634-638-650-652-654-656.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ630>634-
650-652-654.
SMALL CRAFT ADVISORY UNTIL 6 AM EST TUESDAY FOR ANZ656-658.
&&
$$
SYNOPSIS...ALB/MPR
NEAR TERM...ALB/MPR
SHORT TERM...MPR
LONG TERM...LSA
AVIATION...LKB
MARINE...LSA
TIDES/COASTAL FLOODING...AKQ
CLIMATE...AKQ
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
135 AM EST MON FEB 23 2015
.SYNOPSIS...
A COLD AND DRY AIR MASS SETTLES IN TO START THE WEEK. ANOTHER COLD
FRONT SWINGS THROUGH THE REGION TUESDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
CURRENT MOSAIC RADAR IMAGERY SHOWS LIGHT SNOW CONTINUING TO STREAM
ACROSS THE FORECAST AREA...ASSOCIATED WITH A RELATIVELY DRY COLD
FRONT BI-SECTING THE CWA. BEHIND THE FRONT...PRECIPITATION REGIME
TURNS SHOWERY WITH STRIATIONS OF LIGHT SNOW SHOWERS STRETCHING
FROM THE SOUTHERN SHORE OF LAKE ERIE INTO OUR FAR ERN OHIO
COUNTIES. THE LATEST RAP HAS A GOOD HANDLE ON BOTH THE TIMING OF
THE SNOW ALONG THE FRONT AND THE LOCATION/TIMING ON THE SHOWERS
BEHIND IT. CONTINUED TO FOLLOW THE RAP THROUGH THE EARLY MORNING
AS THE MID AND UPPER LEVEL MOISTURE OVERRUNS THE LOW LEVEL
MOISTURE AND THE SNOW CEASES.
TEMPERATURES WILL CONTINUE TO FALL THROUGH THE EARLY
MORNING...BOTTOMING OUT BELOW ZERO NORTH OF I-80...AND THE SINGLE
DIGITS ABOVE ZERO FOR MOST OTHER LOCATIONS. AS THE COLD FRONT
CROSSES...A SUBTLE WIND SHIFT IS NOTED...BUT AN INCREASE IN FLOW
SPEED IS THE BIGGER IMPACT. ALREADY SEEING WIND CHILLS INTO THE
SINGLE DIGITS. SHOULD SEE WIND CHILL VALUES BELOW -10 IN THE NEXT
FEW HOURS LEADING TO YET ANOTHER FRIGID MORNING.
OPTIMISTICALLY CUTTING BACK ON CLOUDS THIS MORNING AND THROUGH THE
BALANCE OF MONDAY. BEHIND THE EXITING FRONT...COPIOUS DRY AIR WILL
CLEAR THE COLUMN. ALL UPSTREAM OBSERVATIONS SHOW CLEAR SKIES AND
WITH LAKE ERIE COMPLETELY FROZEN...NO DOWNSTREAM LAKE-INDUCED CLOUDS
ARE EXPECTED. A DECEPTIVELY SUNNY DAY IS EXPECTED AS TEMPERATURES
WILL REMAIN WELL BELOW AVERAGE. BUMPED HIGHS UP A FEW DEGREES AS
THE INCREASINGLY POTENT LATE FEBRUARY SUNSHINE SHOULD MAKE INROADS
ON THIS LATEST ARCTIC AIRMASS.
TAX
&&
.SHORT TERM /TONIGHT THROUGH 6 PM TUESDAY/...
TEMPERATURES WILL PLUMMET BEHIND THE FRONTAL BOUNDARY WITH MORNING
LOWS PROJECTED AROUND ZERO...ON AVERAGE...ACROSS THE REGION.
CHANGES TO THE PREVIOUS TEMPERATURE FORECAST WERE MINIMAL...BUT
TWEAKS WERE BASED PRIMARILY ON CANADIAN AND ADJUSTED MET GUIDANCE
WHICH HAS PERFORMED WELL AS OF LATE.
PROGGED SURFACE GRADIENTS STILL LOOK SUPPORTIVE OF WIND THAT
WOULD RESULT IN A WIND CHILLS DROPPING BELOW THE -10F THRESHOLD
ACROSS MUCH OF THE REGION BY EARLY MONDAY MORNING. THE WIND CHILL
ADVISORY HAS THUS BEEN EXPANDED TO INCLUDE ALL BUT A FEW COUNTIES
TO THE SOUTH OF INTERSTATE 70...AND HAS BEEN SEGMENTED FOR WIND
CHILL MAGNITUDE AND TIMING.
THE COLD WEATHER WILL CONTINUE INTO MONDAY NIGHT...BUT BUILDING
HIGH PRESSURE IS EXPECTED TO SLACKEN THE WIND AND PRECLUDE A
CONTINUATION OF THE WIND CHILL ADVISORY AS MONDAY EVENING FALLS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
AN UPPER TROUGH OVER THE NORTHEASTERN CONUS...AND ITS ASSOCIATED
SURFACE COLD FRONT...IS PROGGED FOR A LATE TUESDAY NIGHT/EARLY
WEDNESDAY PASSAGE. BEST MOISTURE AND UPPER SUPPORT SHOULD REMAIN
NORTH OF THE AREA SO MAINTAINED ONLY CHANCE POPS FOR SNOW SHOWERS.
A DEAMPLIFIED UPPER PATTERN IS PROGGED TO SET UP FOR THE REMAINDER
OF THE PERIOD WITH MAINLY DRY WEATHER UNTIL THE APPROACH AND
PASSAGE OF A WEEKEND TROUGH.
AFTER A COLD START TEMPERATURES SHOULD BEGIN TO MODERATE BY THE
WEEKEND. WPC GUIDANCE DEPICTED A MODEL BLEND SOLUTION SMOOTHING
OUT MODEL DIFFERENCES...AND WAS USED WITH A FEW TWEAKS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
SLOWED THE EXODUS OF THE ARCTIC FRONT AND ASSOCIATED MVFR SNOW/CLOUDS
THIS MORNING BY A FEW HOURS...BUT GENERALLY EXPECTING IMPROVEMENT
TO VFR BY 12Z. CLOUD COVER SHOULD SCATTER OUT THROUGH MIDDAY WITH
TERMINALS ACROSS THE SOUTH SLOWEST TO LOSE THE COVER. WINDS WILL
STAY FROM THE NORTH...AND SLOWLY GRADUALLY DISSIPATE THROUGH THE
AFTERNOON/EVENING. GENERALLY CLEAR CONDITIONS ARE EXPECTED TONIGHT.
TAX
OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
RESTRICTIONS ARE POSSIBLE WITH A TUESDAY NIGHT/WEDNESDAY COLD
FRONT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL ADVISORY FROM 6 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR MDZ001.
OH...WIND CHILL ADVISORY FROM 4 AM EARLY THIS MORNING TO 1 PM EST
THIS AFTERNOON FOR OHZ039>041-048>050-057>059.
PA...WIND CHILL ADVISORY FROM 4 AM EARLY THIS MORNING TO 1 PM EST
THIS AFTERNOON FOR PAZ020-021-029-073-075.
WIND CHILL ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ007>009-
013>016-022-023.
WIND CHILL ADVISORY FROM 6 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR PAZ074-076.
WV...WIND CHILL ADVISORY FROM 4 AM EARLY THIS MORNING TO 1 PM EST
THIS AFTERNOON FOR WVZ001>003.
WIND CHILL ADVISORY FROM 6 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
302 PM EST MON FEB 23 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO
.SYNOPSIS...
ISSUED AT 239 PM EST MON FEB 23 2015
A FAST MOVING LOW PRESSURE SYSTEM WILL TRACK EASTWARD THROUGH
ONTARIO TONIGHT AND TUESDAY. THIS SYSTEM WILL PROVIDE THE GREAT
LAKES REGION WITH WINDY CONDITIONS AND SOME SNOW. CONSIDERABLE
DRIFTING SNOW WILL BE POSSIBLE ON TUESDAY. ANOTHER ARCTIC AIRMASS
WILL TRACK IN BEHIND THIS DEPARTING STORM AND PERSIST INTO THE WEEKEND.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 239 PM EST MON FEB 23 2015
THE MAIN ISSUE DEALS WITH THE IMPACT OF THE LOW PRESSURE SYSTEM
THAT TRACKS THROUGH ONTARIO TONIGHT AND TUESDAY. OVERALL IT LOOKS
LIKE ENOUGH IMPACTS TO WARRANT HEADLINES FOR THE ENTIRE REGION.
I DID CHECK IN WITH A COUPLE OF ROAD COMMISSIONS AND THEY
INDICATED THAT WINDS OVER 30 MPH WILL LEAD TO CONSIDERABLE
DRIFTING OF THE SNOW...ESPECIALLY IN RURAL AREAS. EVEN SOME
HIGHWAYS COULD BE IMPACTED. THE RUC MODEL SHOWS GUSTS TOPPING 40
KNOTS FROM NEAR GRAND RAPIDS NORTHEAST THROUGH MOUNT PLEASANT AND
BETTER THAN 35 KNOTS ELSEWHERE. THERE IS A SECONDARY MAX ALONG THE
LAKESHORE NORTH OF MUSKEGON...WITH BETTER THAN 40 KNOTS POSSIBLE.
I AM NOT CERTAIN WILL SEE SUCH HIGH WINDS. HOWEVER ENOUGH RISK
THERE TO GO WITH A HEADLINE. THE MAIN WINDOW OF STRONG WINDS
RANGES FROM 09Z TO 18Z FOR LUDINGTON...13Z TO 21Z FOR GRAND RAPIDS
AND 16Z TO 23Z FOR JACKSON.
SNOW ON TUESDAY WILL BE A SECONDARY CONCERN FOR THIS SYSTEM WITH AMOUNTS
EXPECTED TO RANGE FROM 2 TO 4 INCHES OF LAKE ENHANCED SNOW UP
NORTH FROM LUDINGTON TO HARRISON. FURTHER SOUTH GRAND RAPIDS AND
MOUNT PLEASANT ROUGHLY 1 TO 3 INCHES...TO AN INCH OR LESS FOR
JACKSON AND LANSING. STILL...WITH GUSTY WINDS AND
SNOW...VISIBILITIES COULD BE REDUCED CONSIDERABLY AT TIMES.
LOCATIONS SOUTHEAST OF GRAND RAPIDS COULD START THE DAY OFF WITH
SOME SUN.
WIND CHILL VALUES ON TUESDAY COULD START OFF AROUND -15
DEGREES...WHICH IS HAZARDOUS.
TUESDAY NIGHT AFTER A LULL IN THE WIND...WE COULD SEE A RETURN OF
SNOW AND POSSIBLE IMPACTS...MAINLY AFTER MIDNIGHT. WILL NEED TO
ASSESS THIS POSSIBILITY WITH LATER FORECASTS.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 239 PM EST MON FEB 23 2015
THE FOCUS OF THE LONG TERM IS THE EVOLUTION OF A SOUTHERN STREAM
SYSTEM THAT BOTH THE GFS AND ECMWF HAVE LATCHED ONTO FOR A COUPLE OF
DAYS NOW. CONDITIONS LOOK PRETTY DRY...BUT COLD FROM THURSDAY
THROUGH SATURDAY...AND LIKELY MONDAY TOO. HOWEVER IT`S THE PERIOD
FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT THAT PROMISES TO BE
INTERESTING.
IT/S LOOKING INCREASINGLY LIKELY THAT PCPN WILL DEVELOP OVER THE SW
CWA SATURDAY EVENING...LIKELY AS SNOW...AND CONTINUE THROUGH SUNDAY.
THE GULF IS WIDE OPEN DUE TO HIGH PRESSURE NEAR THE EAST COAST AND
SO THERE WILL BE A STRONG INFLUX OF MOISTURE. DESPITE THE MOISTURE
CONTENT OF THIS SYSTEM...IT STILL HAS SOME ISSUES. ECMWF AND GFS
BOTH SHOW THIS BEGINNING AS AN INVERTED TROUGH AND THEN PHASING WITH
A NORTHERN STREAM CLIPPER AS IT PUSHES A COLD FRONT THROUGH THE CWA.
THIS ISN/T THE CLASSIC STRENGTHENING CLOSED LOW THAT MOVES FROM THE
SOUTHERN PLAINS NEWD. AT LEAST NOT YET. QPF WITH THE SYSTEM IS PROGD
IN THE 2/3 TO 3/4 INCH RANGE...WHICH IF ALL SNOW WOULD CERTAINLY BE
PLOWABLE. THE WARMER ECMWF WOULD LIKELY TURN PCPN TO MIXED RAIN AND
SNOW ACROSS THE SOUTHERN CWA. FOR CONTINUITY SAKE WE KEPT THE PCPN
AS SNOW IN THE GRIDS FOR NOW.
ALL OF THE PCPN WILL LIKELY END MONDAY AS THE SYSTEM MOVES EAST AND
ANOTHER SHOT OF COLD AIR MOVES SOUTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1240 PM EST MON FEB 23 2015
LAKE EFFECT SNOW SHOWERS WILL DIMINISH THIS AFTERNOON AT MKG AND
MAY INCREASE A BIT AT GRR AS THE BAND PUSHES INLAND. IT`S POSSIBLE
THAT WE COULD SEE A MVFR CIG AT GRR THIS AFTERNOON.
OTHERWISE...WINDS WILL INCREASE FROM THE SOUTHWEST AFTER MIDNIGHT
AS ANOTHER SYSTEM APPROACHES. SNOW WILL DEVELOP TUESDAY MORNING AT
MKG BUT MAY TAKE UNTIL THE AFTERNOON TO DEVELOP AT THE OTHER TAF SITES.
&&
.HYDROLOGY...
ISSUED AT 239 PM EST MON FEB 23 2015
WITH NO MAJOR WARM UPS OR RAINFALL HEADED OUR WAY IN THE NEAR
FUTURE...RUNOFF WILL BE LIMITED. SERIOUS ICE JAMS AND FLOODING
CONCERNS ARE UNLIKELY UNTIL A SIGNIFICANT WARM UP AND RAINFALL
OCCUR. CONSIDERABLE ICE DOES EXIST IN THE RIVERS SO WE WILL NEED
TO MONITOR TRENDS CLOSELY. FOR NOW WITH CONDITIONS STABLE DUE TO
THE ARCTIC AIRMASS IN PLACE...THE RISK IS SOMEWHAT LIMITED FOR
FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST TUESDAY FOR
MIZ037>040-043>046-050>052-056>059-064>067-071>074.
LM...NONE.
&&
$$
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...04
AVIATION...04
HYDROLOGY...MJS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1217 PM EST MON FEB 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 532 AM EST MON FEB 23 2015
WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT RIDGE FROM THE ERN
PACIFIC INTO BC AND MID LEVEL LOW NEAR JAMES BAY RESULTING IN NNW
FLOW FROM NRN CANADA INTO THE WRN GREAT LAKES. A VIGOROUS UPSTREAM
SHORTWAVE TROUGH WAS LOCATED OVER NRN CANADA. AT THE SFC...LIGHT
WRLY FLOW PREVAILED ACROSS THE REGION AS ARCTIC HIGH PRES SLOWLY
BUILDS TO THE SE TO WRN IA. WITH THE EXTENSIVE ICE COVER ACROSS LAKE
SUPERIOR...RADAR/SATELLITE INDICATED ONLY MINIMAL/WEAK LES TO NEAR
MUNISING AND GRAND MARAIS THAT WAS SLOWLY LIFTING OFFSHORE AS WINDS
BACK. EARLY MORNING TEMPS GENERALLY RANGING BETWEEN -10F TO -20F
ALONG WITH WINDS AROUND 5 MPH PRODUCED WIND CHILLS IN THE -20 TO -35
RANGE.
TODAY...WIND CHILL VALUES WILL ONLY SLOWLY MODERATE THIS MORNING AS
TEMPS CLIMBING BACK TOWARD ZERO WILL BE OFFSET BY INCREASING SW
WINDS TO AROUND 10 MPH. OTHERWISE...QUIET WEATHER IS EXPECTED WITH
GRADUALLY INCREASING MID AND HIGH CLOUDS IN THE WAA PATTERN BETWEEN
THE RETREATING HIGH AND THE CLIPPER LOW MOVING SSE FROM CANADA. THE
TIGHTENING PRES GRADIENT WILL BRING GUSTY WINDS BY LATE TODAY MAKING
IT STILL FEEL VERY COLD EVEN AS TEMPS CLIMB TO HIGHS NEAR 10F.
TONIGHT...THE NRN CANADA SHRTWV WILL QUICKLY DIVE TO THE SSE TO THE
NORTH SHORE OF LAKE SUPERIOR BY 12Z/TUE. THE WAA AND PATTERN AND
280K ISENTROPIC LIFT AHEAD OF THE TROUGH WILL BRING WIDESREAD LIGHT
SNOW TO THE REGION. EXPECT A DELAY TO THE ONSET OF SNOW TIL LATE
EVENING AND OVERNIGHT GIVEN THE VERY DRY AIRMASS IN PLACE OVER THE
REGION AND THE TIME TO SATURATE THE 925-700 MB LAYER...PER FCST
SOUNDINGS. POTENTIAL SNOWFALL AMOUNTS OF A HALF INCH TO AROUND 2
INCHES ARE CONSISTENT WITH 1.0-1.5 G/KG AVAILABLE DURING THE PERIOD
OF STRONGER LIFT AND QPF BETWEEN 0.03-0.08 WITH SLR VALUES AROUND
20/1. THE GREATEST AMOUNTS ARE EXPECTED FROM THE KEWEENAW INTO THE
ERN CWA WHERE THE FCST LIFT AND A LONGER PERIOD OF SATURATION IS
FCST. POTENTIAL FOR LAKE ENHANCEMENT WITH SW FLOW OFF OF SOME
REMAINING OPEN WATER IN NRN LAKE MI SHOULD REMAIN MAINLY EAST OF THE
CWA...PER HIGHER RES MODELS 230-250 FCST LOW LEVEL FLOW DIRECTION.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 250 AM EST MON FEB 23 2015
TUESDAY THROUGH SUNDAY WILL BE MARKED BY BOOKEND LOW PRESSURE
SYSTEMS...WITH HIGH PRESSURE IN BETWEEN. THE FIRST AT 12Z TUESDAY
WILL BE SET UP FROM S HUDSON BAY THROUGH CENTRAL ONTARIO...AND
CENTRAL LAKE SUPERIOR...DRAGGING A COLD FRONT ACROSS THE W THIRD OF
THE CWA. THE FRONTAL BOUNDARY WILL SWIFTLY EXIT E...AND RESIDE FROM
JAMES BAY THRUOGH FAR SE LAKE SUPERIOR BY 18Z TUESDAY. 1-2 IN OF NEW
SNOW WILL BE POSSIBLE TUESDAY OVER MUCH OF THE CWA...WITH THE
HIGHEST VALUES FAR N AND E. WHILE WINDS ALOFT WILL BE DIMINISHING
FROM THE 40-50KT WINDS OVERNIGHT...SFC WINDS WILL BE STEADY TO ON
THE INCREASE. LOOK FOR WINDS OF 10-20KTS DURING THE DAY
TUESDAY...HIGHEST W AND ALONG LAKE SUPERIOR.
WILL BE INTERESTING TO SEE WHAT THE INCREASED SW WINDS TODAY-
TONIGHT...AND NW WINDS TUESDAY DO TO THE RELATIVLY THIN AND
FRACTURED ICE COVERING MUCH OF LAKE SUPERIOR. HOW IT PROGRESSES WILL
HAVE A LARGE IMPACT ON THE AREAL COVERAGE AND INTENSITY OF LAKE
EFFECT SNOW BANDS TUESDAY AFTERNOON THROUGH THURSDAY ON MAINLY NW TO
WNW WINDS.
SLOWLY FALLING INVERSION HEIGHTS TUESDAY NIGHT...AND THE DGZ GOING
AWAY AS MUCH COLDER AIR SLIDES IN ON THE NW WINDS WILL RESULT IN THE
RETURN OF SMALL SNOWFLAKES THAT WILL NOT ACCUMULATE TO MUCH BUT ARE
VERY AFFECTIVE AT REDUCING VIS. ANOTHER COLD ARCTIC ARIMASS WILL BE
ABLE TO SLIDE INTO THE REGION AS HIGH PRESSURE OVER MUCH OF THE W
HALF OF CANADA SLOWLY SINKS ACROSS S CENTRAL CANADA...THE N AND
CENTRAL PLAINS...AND THE UPPER GREAT LAKES BY THE END OF THE WORK
WEEK. LIGHT LES ON N TO WNW WINDS WILL BE THE RULE.
WIND CHILL VALUES WILL AGAIN FALL INTO THE -20 TO -30F RANGE LATE
TUESDAY NIGHT THROUGH WEDNESDAY MORNING. THAT 10MPH WIND PORTION OF
THE WIND CHILL ADVISORY SHOULD BE MET ACROSS MOST OF THE CWA...WITH
STRONGER NW WINDS NEARING 15MPH N CENTRAL AND E ALONG LAKE SUPERIOR.
THE APPARENT TEMPERATURE PORTION OF WIND CHILL ADVISORY CRITERIA IS
-25 TO -34F.
LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING MAY AGAIN BRING US
DOWN TO 20 TO NEAR 30 BELOW ZERO WIND CHILLS. HOWEVER...THE NW WINDS
SHOULD BE MUCH LIGHTER.
THURSDAY NIGHT-FRIDAY WILL BE A PERIOD OF MAINLY W TO WSW WINDS.
LAKE EFFECT SNOW SHOWERS SHOULD BE EITHER MIMIMAL OR NON-
EXISTANT...AND IMPACTING THE KEWEENAW PENINSULA AND RIGHT ALONG THE
LAKE SUPERIOR SHORELINE AROUND AND E OF GRAND MARAIS.
EXPECT DRY WEATHER SATURDAY...BUT INCREASING SW WINDS AND INVADING
CLOUDS FROM THE W. 850MB TEMPS WILL RISE TO AROUND -11 TO -13C
SATURDAY AND SUNDAY. SFC TEMPERATURES SHOULD REBOUND TO NEAR
20F...WHICH IS STILL AROUND 10 DEGREES BELOW NORMAL FOR THIS TIME OF
YEAR. SUNDAY SHOULD BE A COUPLE DEGREES WARMER...BUT FILLED WITH
MORE CLOUDS AND SNOW FOR THE ENTIRE CWA. EARLY INDICATIONS FROM THE
GFS POINT TO 2-5IN OF SNOW CWA WIDE LATE SATURDAY AFTERNOON THROUGH
SUNDAY EVENING. THE BEST MOISTURE LOOKS TO REMAIN TO OUR S AS UPPER
MI IS IN BETWEEN 2 LOWS /ONE OVER HUDSON BAY...AND ANOTHER EJECTING
OUT OF THE CENTRAL PLAINS/.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1217 PM EST MON FEB 23 2015
VFR CONDITIONS WILL CONTINUE AT ALL 3 TAF SITES INTO THIS EVENING.
THE SW WINDS WILL STRENGTHEN AND TURN GUSTY AS THE PRESSURE GRADIENT
TIGHTENS AHEAD OF A COLD FRONT APPROACHING FROM THE NW. SNOW IN
ADVANCE OF THIS FRONT WILL ARRIVE FROM NW TO SE LATE THIS EVENING.
THE DRY NATURE OF THE ANTECEDENT AIRMASS WILL MAINTAIN VFR
CONDITIONS INITIALLY DESPITE THE THICKENING CLOUD COVER.
HOWEVER...CONDITIONS WILL DROP TO MVFR AFT 06Z AND LIKELY TO IFR AT
CMX AND IWD WHERE THE HEAVIER SNOW IS EXPECTED AND THE VISIBILITY
WILL BE LOW DUE TO BLOWING SNOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 532 AM EST MON FEB 23 2015
SOUTHWEST WINDS WILL QUICKLY INCREASE THIS AFTERNOON BETWEEN LOW
PRESSURE DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO AND HIGH PRES
MOVING INTO THE OH VALLEY. THIS WILL LEAD TO SOUTHWESTERLY GALES OF
35-40KTS OVER PORTIONS OF LAKE SUPERIOR THIS AFTERNOON AND EVENING.
A GALE WARNING REMAINS IN EFFECT FOR MUCH OF WESTERN/CENTRAL LAKE
SUPERIOR FOR LATE THIS AFTERNOON AND TONIGHT. THEN AS A COLD FRONT
SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE TONIGHT INTO TUESDAY
MORNING AND SHIFT WINDS TO THE NORTHWEST...THERE MAY BE A FEW GALE
FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER EASTERN
LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO THE AREA
WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY LIGHT WINDS
BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR
LSZ266.
GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST
/6 AM CST/ TUESDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
637 AM EST MON FEB 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 532 AM EST MON FEB 23 2015
WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT RIDGE FROM THE ERN
PACIFIC INTO BC AND MID LEVEL LOW NEAR JAMES BAY RESULTING IN NNW
FLOW FROM NRN CANADA INTO THE WRN GREAT LAKES. A VIGOROUS UPSTREAM
SHORTWAVE TROUGH WAS LOCATED OVER NRN CANADA. AT THE SFC...LIGHT
WRLY FLOW PREVAILED ACROSS THE REGION AS ARCTIC HIGH PRES SLOWLY
BUILDS TO THE SE TO WRN IA. WITH THE EXTENSIVE ICE COVER ACROSS LAKE
SUPERIOR...RADAR/SATELLITE INDICATED ONLY MINIMAL/WEAK LES TO NEAR
MUNISING AND GRAND MARAIS THAT WAS SLOWLY LIFTING OFFSHORE AS WINDS
BACK. EARLY MORNING TEMPS GENERALLY RANGING BETWEEN -10F TO -20F
ALONG WITH WINDS AROUND 5 MPH PRODUCED WIND CHILLS IN THE -20 TO -35
RANGE.
TODAY...WIND CHILL VALUES WILL ONLY SLOWLY MODERATE THIS MORNING AS
TEMPS CLIMBING BACK TOWARD ZERO WILL BE OFFSET BY INCREASING SW
WINDS TO AROUND 10 MPH. OTHERWISE...QUIET WEATHER IS EXPECTED WITH
GRADUALLY INCREASING MID AND HIGH CLOUDS IN THE WAA PATTERN BETWEEN
THE RETREATING HIGH AND THE CLIPPER LOW MOVING SSE FROM CANADA. THE
TIGHTENING PRES GRADIENT WILL BRING GUSTY WINDS BY LATE TODAY MAKING
IT STILL FEEL VERY COLD EVEN AS TEMPS CLIMB TO HIGHS NEAR 10F.
TONIGHT...THE NRN CANADA SHRTWV WILL QUICKLY DIVE TO THE SSE TO THE
NORTH SHORE OF LAKE SUPERIOR BY 12Z/TUE. THE WAA AND PATTERN AND
280K ISENTROPIC LIFT AHEAD OF THE TROUGH WILL BRING WIDESREAD LIGHT
SNOW TO THE REGION. EXPECT A DELAY TO THE ONSET OF SNOW TIL LATE
EVENING AND OVERNIGHT GIVEN THE VERY DRY AIRMASS IN PLACE OVER THE
REGION AND THE TIME TO SATURATE THE 925-700 MB LAYER...PER FCST
SOUNDINGS. POTENTIAL SNOWFALL AMOUNTS OF A HALF INCH TO AROUND 2
INCHES ARE CONSISTENT WITH 1.0-1.5 G/KG AVAILABLE DURING THE PERIOD
OF STRONGER LIFT AND QPF BETWEEN 0.03-0.08 WITH SLR VALUES AROUND
20/1. THE GREATEST AMOUNTS ARE EXPECTED FROM THE KEWEENAW INTO THE
ERN CWA WHERE THE FCST LIFT AND A LONGER PERIOD OF SATURATION IS
FCST. POTENTIAL FOR LAKE ENHANCEMENT WITH SW FLOW OFF OF SOME
REMAINING OPEN WATER IN NRN LAKE MI SHOULD REMAIN MAINLY EAST OF THE
CWA...PER HIGHER RES MODELS 230-250 FCST LOW LEVEL FLOW DIRECTION.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 250 AM EST MON FEB 23 2015
TUESDAY THROUGH SUNDAY WILL BE MARKED BY BOOKEND LOW PRESSURE
SYSTEMS...WITH HIGH PRESSURE IN BETWEEN. THE FIRST AT 12Z TUESDAY
WILL BE SET UP FROM S HUDSON BAY THROUGH CENTRAL ONTARIO...AND
CENTRAL LAKE SUPERIOR...DRAGGING A COLD FRONT ACROSS THE W THIRD OF
THE CWA. THE FRONTAL BOUNDARY WILL SWIFTLY EXIT E...AND RESIDE FROM
JAMES BAY THRUOGH FAR SE LAKE SUPERIOR BY 18Z TUESDAY. 1-2 IN OF NEW
SNOW WILL BE POSSIBLE TUESDAY OVER MUCH OF THE CWA...WITH THE
HIGHEST VALUES FAR N AND E. WHILE WINDS ALOFT WILL BE DIMINISHING
FROM THE 40-50KT WINDS OVERNIGHT...SFC WINDS WILL BE STEADY TO ON
THE INCREASE. LOOK FOR WINDS OF 10-20KTS DURING THE DAY
TUESDAY...HIGHEST W AND ALONG LAKE SUPERIOR.
WILL BE INTERESTING TO SEE WHAT THE INCREASED SW WINDS TODAY-
TONIGHT...AND NW WINDS TUESDAY DO TO THE RELATIVLY THIN AND
FRACTURED ICE COVERING MUCH OF LAKE SUPERIOR. HOW IT PROGRESSES WILL
HAVE A LARGE IMPACT ON THE AREAL COVERAGE AND INTENSITY OF LAKE
EFFECT SNOW BANDS TUESDAY AFTERNOON THROUGH THURSDAY ON MAINLY NW TO
WNW WINDS.
SLOWLY FALLING INVERSION HEIGHTS TUESDAY NIGHT...AND THE DGZ GOING
AWAY AS MUCH COLDER AIR SLIDES IN ON THE NW WINDS WILL RESULT IN THE
RETURN OF SMALL SNOWFLAKES THAT WILL NOT ACCUMULATE TO MUCH BUT ARE
VERY AFFECTIVE AT REDUCING VIS. ANOTHER COLD ARCTIC ARIMASS WILL BE
ABLE TO SLIDE INTO THE REGION AS HIGH PRESSURE OVER MUCH OF THE W
HALF OF CANADA SLOWLY SINKS ACROSS S CENTRAL CANADA...THE N AND
CENTRAL PLAINS...AND THE UPPER GREAT LAKES BY THE END OF THE WORK
WEEK. LIGHT LES ON N TO WNW WINDS WILL BE THE RULE.
WIND CHILL VALUES WILL AGAIN FALL INTO THE -20 TO -30F RANGE LATE
TUESDAY NIGHT THROUGH WEDNESDAY MORNING. THAT 10MPH WIND PORTION OF
THE WIND CHILL ADVISORY SHOULD BE MET ACROSS MOST OF THE CWA...WITH
STRONGER NW WINDS NEARING 15MPH N CENTRAL AND E ALONG LAKE SUPERIOR.
THE APPARENT TEMPERATURE PORTION OF WIND CHILL ADVISORY CRITERIA IS
-25 TO -34F.
LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING MAY AGAIN BRING US
DOWN TO 20 TO NEAR 30 BELOW ZERO WIND CHILLS. HOWEVER...THE NW WINDS
SHOULD BE MUCH LIGHTER.
THURSDAY NIGHT-FRIDAY WILL BE A PERIOD OF MAINLY W TO WSW WINDS.
LAKE EFFECT SNOW SHOWERS SHOULD BE EITHER MIMIMAL OR NON-
EXISTANT...AND IMPACTING THE KEWEENAW PENINSULA AND RIGHT ALONG THE
LAKE SUPERIOR SHORELINE AROUND AND E OF GRAND MARAIS.
EXPECT DRY WEATHER SATURDAY...BUT INCREASING SW WINDS AND INVADING
CLOUDS FROM THE W. 850MB TEMPS WILL RISE TO AROUND -11 TO -13C
SATURDAY AND SUNDAY. SFC TEMPERATURES SHOULD REBOUND TO NEAR
20F...WHICH IS STILL AROUND 10 DEGREES BELOW NORMAL FOR THIS TIME OF
YEAR. SUNDAY SHOULD BE A COUPLE DEGREES WARMER...BUT FILLED WITH
MORE CLOUDS AND SNOW FOR THE ENTIRE CWA. EARLY INDICATIONS FROM THE
GFS POINT TO 2-5IN OF SNOW CWA WIDE LATE SATURDAY AFTERNOON THROUGH
SUNDAY EVENING. THE BEST MOISTURE LOOKS TO REMAIN TO OUR S AS UPPER
MI IS IN BETWEEN 2 LOWS /ONE OVER HUDSON BAY...AND ANOTHER EJECTING
OUT OF THE CENTRAL PLAINS/.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 637 AM EST MON FEB 23 2015
AFTER A PERIOD OF MVFR CIGS EARLY AT KMCX FROM LIMITED MOISTENING
FROM UPSTREAM GAPS IN THE ICE COVER ON LAKE SUPERIOR...A STEADY WNW
SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HIGH PRES MOVING INTO
THE OH RIVER VALLEY WILL RESULT IN VFR CONDITIONS AT ALL 3 TAF SITES
INTO THIS EVENING. THE SW WINDS WILL STRENGTHEN AND TURN GUSTY THIS
AFTERNOON AS THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FRONT
APPROACHING FROM THE NW. SNOW IN ADVANCE OF THIS FRONT WILL ARRIVE
FROM NW TO SE LATE THIS EVENING. THE DRY NATURE OF THE ANTECEDENT
AIRMASS WILL MAINTAIN VFR CONDITIONS INITIALLY DESPITE THE
THICKENING CLOUDD COVER. HOWEVER...CONDITIONS WILL DROP TO MVFR AFT
06Z AND LIKELY TO IFR AT CMX WHERE THE HEAVIER SNOW IS EXPECTED.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 532 AM EST MON FEB 23 2015
SOUTHWEST WINDS WILL QUICKLY INCREASE THIS AFTERNOON BETWEEN LOW
PRESSURE DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO AND HIGH PRES
MOVING INTO THE OH VALLEY. THIS WILL LEAD TO SOUTHWESTERLY GALES OF
35-40KTS OVER PORTIONS OF LAKE SUPERIOR THIS AFTERNOON AND EVENING.
A GALE WARNING REMAINS IN EFFECT FOR MUCH OF WESTERN/CENTRAL LAKE
SUPERIOR FOR LATE THIS AFTERNOON AND TONIGHT. THEN AS A COLD FRONT
SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE TONIGHT INTO TUESDAY
MORNING AND SHIFT WINDS TO THE NORTHWEST...THERE MAY BE A FEW GALE
FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER EASTERN
LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO THE AREA
WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY LIGHT WINDS
BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR
MIZ001>007-009>014-084-085.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR
LSZ266.
GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST
/6 AM CST/ TUESDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
532 AM EST MON FEB 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 532 AM EST MON FEB 23 2015
WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT RIDGE FROM THE ERN
PACIFIC INTO BC AND MID LEVEL LOW NEAR JAMES BAY RESULTING IN NNW
FLOW FROM NRN CANADA INTO THE WRN GREAT LAKES. A VIGOROUS UPSTREAM
SHORTWAVE TROUGH WAS LOCATED OVER NRN CANADA. AT THE SFC...LIGHT
WRLY FLOW PREVAILED ACROSS THE REGION AS ARCTIC HIGH PRES SLOWLY
BUILDS TO THE SE TO WRN IA. WITH THE EXTENSIVE ICE COVER ACROSS LAKE
SUPERIOR...RADAR/SATELLITE INDICATED ONLY MINIMAL/WEAK LES TO NEAR
MUNISING AND GRAND MARAIS THAT WAS SLOWLY LIFTING OFFSHORE AS WINDS
BACK. EARLY MORNING TEMPS GENERALLY RANGING BETWEEN -10F TO -20F
ALONG WITH WINDS AROUND 5 MPH PRODUCED WIND CHILLS IN THE -20 TO -35
RANGE.
TODAY...WIND CHILL VALUES WILL ONLY SLOWLY MODERATE THIS MORNING AS
TEMPS CLIMBING BACK TOWARD ZERO WILL BE OFFSET BY INCREASING SW
WINDS TO AROUND 10 MPH. OTHERWISE...QUIET WEATHER IS EXPECTED WITH
GRADUALLY INCREASING MID AND HIGH CLOUDS IN THE WAA PATTERN BETWEEN
THE RETREATING HIGH AND THE CLIPPER LOW MOVING SSE FROM CANADA. THE
TIGHTENING PRES GRADIENT WILL BRING GUSTY WINDS BY LATE TODAY MAKING
IT STILL FEEL VERY COLD EVEN AS TEMPS CLIMB TO HIGHS NEAR 10F.
TONIGHT...THE NRN CANADA SHRTWV WILL QUICKLY DIVE TO THE SSE TO THE
NORTH SHORE OF LAKE SUPERIOR BY 12Z/TUE. THE WAA AND PATTERN AND
280K ISENTROPIC LIFT AHEAD OF THE TROUGH WILL BRING WIDESREAD LIGHT
SNOW TO THE REGION. EXPECT A DELAY TO THE ONSET OF SNOW TIL LATE
EVENING AND OVERNIGHT GIVEN THE VERY DRY AIRMASS IN PLACE OVER THE
REGION AND THE TIME TO SATURATE THE 925-700 MB LAYER...PER FCST
SOUNDINGS. POTENTIAL SNOWFALL AMOUNTS OF A HALF INCH TO AROUND 2
INCHES ARE CONSISTENT WITH 1.0-1.5 G/KG AVAILABLE DURING THE PERIOD
OF STRONGER LIFT AND QPF BETWEEN 0.03-0.08 WITH SLR VALUES AROUND
20/1. THE GREATEST AMOUNTS ARE EXPECTED FROM THE KEWEENAW INTO THE
ERN CWA WHERE THE FCST LIFT AND A LONGER PERIOD OF SATURATION IS
FCST. POTENTIAL FOR LAKE ENHANCEMENT WITH SW FLOW OFF OF SOME
REMAINING OPEN WATER IN NRN LAKE MI SHOULD REMAIN MAINLY EAST OF THE
CWA...PER HIGHER RES MODELS 230-250 FCST LOW LEVEL FLOW DIRECTION.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 250 AM EST MON FEB 23 2015
TUESDAY THROUGH SUNDAY WILL BE MARKED BY BOOKEND LOW PRESSURE
SYSTEMS...WITH HIGH PRESSURE IN BETWEEN. THE FIRST AT 12Z TUESDAY
WILL BE SET UP FROM S HUDSON BAY THROUGH CENTRAL ONTARIO...AND
CENTRAL LAKE SUPERIOR...DRAGGING A COLD FRONT ACROSS THE W THIRD OF
THE CWA. THE FRONTAL BOUNDARY WILL SWIFTLY EXIT E...AND RESIDE FROM
JAMES BAY THRUOGH FAR SE LAKE SUPERIOR BY 18Z TUESDAY. 1-2 IN OF NEW
SNOW WILL BE POSSIBLE TUESDAY OVER MUCH OF THE CWA...WITH THE
HIGHEST VALUES FAR N AND E. WHILE WINDS ALOFT WILL BE DIMINISHING
FROM THE 40-50KT WINDS OVERNIGHT...SFC WINDS WILL BE STEADY TO ON
THE INCREASE. LOOK FOR WINDS OF 10-20KTS DURING THE DAY
TUESDAY...HIGHEST W AND ALONG LAKE SUPERIOR.
WILL BE INTERESTING TO SEE WHAT THE INCREASED SW WINDS TODAY-
TONIGHT...AND NW WINDS TUESDAY DO TO THE RELATIVLY THIN AND
FRACTURED ICE COVERING MUCH OF LAKE SUPERIOR. HOW IT PROGRESSES WILL
HAVE A LARGE IMPACT ON THE AREAL COVERAGE AND INTENSITY OF LAKE
EFFECT SNOW BANDS TUESDAY AFTERNOON THROUGH THURSDAY ON MAINLY NW TO
WNW WINDS.
SLOWLY FALLING INVERSION HEIGHTS TUESDAY NIGHT...AND THE DGZ GOING
AWAY AS MUCH COLDER AIR SLIDES IN ON THE NW WINDS WILL RESULT IN THE
RETURN OF SMALL SNOWFLAKES THAT WILL NOT ACCUMULATE TO MUCH BUT ARE
VERY AFFECTIVE AT REDUCING VIS. ANOTHER COLD ARCTIC ARIMASS WILL BE
ABLE TO SLIDE INTO THE REGION AS HIGH PRESSURE OVER MUCH OF THE W
HALF OF CANADA SLOWLY SINKS ACROSS S CENTRAL CANADA...THE N AND
CENTRAL PLAINS...AND THE UPPER GREAT LAKES BY THE END OF THE WORK
WEEK. LIGHT LES ON N TO WNW WINDS WILL BE THE RULE.
WIND CHILL VALUES WILL AGAIN FALL INTO THE -20 TO -30F RANGE LATE
TUESDAY NIGHT THROUGH WEDNESDAY MORNING. THAT 10MPH WIND PORTION OF
THE WIND CHILL ADVISORY SHOULD BE MET ACROSS MOST OF THE CWA...WITH
STRONGER NW WINDS NEARING 15MPH N CENTRAL AND E ALONG LAKE SUPERIOR.
THE APPARENT TEMPERATURE PORTION OF WIND CHILL ADVISORY CRITERIA IS
-25 TO -34F.
LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING MAY AGAIN BRING US
DOWN TO 20 TO NEAR 30 BELOW ZERO WIND CHILLS. HOWEVER...THE NW WINDS
SHOULD BE MUCH LIGHTER.
THURSDAY NIGHT-FRIDAY WILL BE A PERIOD OF MAINLY W TO WSW WINDS.
LAKE EFFECT SNOW SHOWERS SHOULD BE EITHER MIMIMAL OR NON-
EXISTANT...AND IMPACTING THE KEWEENAW PENINSULA AND RIGHT ALONG THE
LAKE SUPERIOR SHORELINE AROUND AND E OF GRAND MARAIS.
EXPECT DRY WEATHER SATURDAY...BUT INCREASING SW WINDS AND INVADING
CLOUDS FROM THE W. 850MB TEMPS WILL RISE TO AROUND -11 TO -13C
SATURDAY AND SUNDAY. SFC TEMPERATURES SHOULD REBOUND TO NEAR
20F...WHICH IS STILL AROUND 10 DEGREES BELOW NORMAL FOR THIS TIME OF
YEAR. SUNDAY SHOULD BE A COUPLE DEGREES WARMER...BUT FILLED WITH
MORE CLOUDS AND SNOW FOR THE ENTIRE CWA. EARLY INDICATIONS FROM THE
GFS POINT TO 2-5IN OF SNOW CWA WIDE LATE SATURDAY AFTERNOON THROUGH
SUNDAY EVENING. THE BEST MOISTURE LOOKS TO REMAIN TO OUR S AS UPPER
MI IS IN BETWEEN 2 LOWS /ONE OVER HUDSON BAY...AND ANOTHER EJECTING
OUT OF THE CENTRAL PLAINS/.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1220 AM EST MON FEB 23 2015
A STEADY WNW SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HI PRES
MOVING INTO THE OH RIVER VALLEY WL RESULT IN VFR CONDITIONS AT ALL 3
TAF SITES INTO THIS EVNG. ALTHOUGH THE W WIND WL UPSLOPE INTO CMX
EARLY THIS MRNG...THE UPSTREAM AIRMASS IS SO DRY AND LK SUP
SUFFICIENTLY ICE COVERED TO LIMIT THE POTENTIAL FOR LES OR EVEN MUCH
IN THE WAY OF LK CLDS. THE SW WINDS WL STRENGTHEN AND TURN GUSTY
THIS AFTN AS THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FNT APRCHG
FM THE NW. SN IN ADVANCE OF THIS FNT WL ARRIVE NW-SE LATE THIS EVNG.
DRY NATURE OF THE ANTECEDENT AIRMASS WL MAINTAIN VFR CONDITIONS
INITIALLY DESPITE THE THICKENING CLD COVER AND ARRIVING -SN. BEST
CHC FOR MVFR CONDITIONS BEFORE 24/06Z WL BE AT CMX...WHERE THE PCPN
WL ARRIVE EARLIEST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 532 AM EST MON FEB 23 2015
SOUTHWEST WINDS WILL QUICKLY INCREASE THIS AFTERNOON BETWEEN LOW
PRESSURE DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO AND HIGH PRES
MOVING INTO THE OH VALLEY. THIS WILL LEAD TO SOUTHWESTERLY GALES OF
35-40KTS OVER PORTIONS OF LAKE SUPERIOR THIS AFTERNOON AND EVENING.
A GALE WARNING REMAINS IN EFFECT FOR MUCH OF WESTERN/CENTRAL LAKE
SUPERIOR FOR LATE THIS AFTERNOON AND TONIGHT. THEN AS A COLD FRONT
SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE TONIGHT INTO TUESDAY
MORNING AND SHIFT WINDS TO THE NORTHWEST...THERE MAY BE A FEW GALE
FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER EASTERN
LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO THE AREA
WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY LIGHT WINDS
BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR
MIZ001>007-009>014-084-085.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR
LSZ266.
GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST
/6 AM CST/ TUESDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
250 AM EST MON FEB 23 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 305 PM EST SUN FEB 22 2015
A VERY COLD UPPER TROUGH IS SLIDING EAST ACROSS THE UPPER GREAT
LAKES REGION THIS AFTERNOON...WITH RAP ANALYZED 850MB TEMPS OF -29C
OVER WESTERN LAKE SUPERIOR. THIS HAS LED TO AFTERNOON TEMPERATURES
AROUND 25-30 DEGREES BELOW THE NORMAL HIGHS FOR THIS TIME OF YEAR
WITH 2PM TEMPERATURES RANGING FROM -10 AT KCMX TO 7 AT KMNM. THE
COLD AIR AND A FEW BREAKS IN THE ICE...OR AT LEAST AREAS OF THIN
ICE...HAS CONTINUED TO LEAD TO VERY THIN BANDS OF LAKE EFFECT OFF
LAKE SUPERIOR IN THE NORTHWEST WIND SNOW BELTS. WHILE THE BANDS HAVE
BEEN THIN...OBS AND WEBCAMS HAVE SHOWN THAT THEY CONTINUE TO BE
EFFICIENT AT REDUCING VISIBILITIES WITH ALL OF THE CLOUDY WELL BELOW
THE DGZ. THOSE VERY LOCALIZED LOWER VISIBILITIES HAVE ALSO BEEN
AIDED BY BLOWING SNOW FROM THE GUSTY NORTHWEST WINDS OF 15-30MPH.
MEANWHILE...A SURFACE HIGH IS CURRENTLY LOCATED OVER THE EASTERN
DAKOTAS AND AN ASSOCIATED SURFACE RIDGE IS NOSING INTO THE UPPER
GREAT LAKES.
THE HIGH WILL DROP SOUTHEAST INTO THE MID MISSISSIPPI VALLEY
TONIGHT...WHICH WILL PUSH A RIDGE ACROSS THE UPPER GREAT LAKES
REGION. THIS RIDGE WILL LEAD TO BACKING WINDS THROUGH THE
NIGHT...BECOMING SOUTHWESTERLY LATE TONIGHT OVER THE WEST AND MONDAY
MORNING OVER THE EAST. THESE BACKING WINDS...ALONG WITH INCREASING
SUBSIDENCE...WILL DIMINISH THE LAKE EFFECT POTENTIAL FROM THE
LIMITED HEATING FROM LAKE SUPERIOR. THUS...EXPECT SKIES TO BECOME
MOSTLY CLEAR THIS EVENING OVER MUCH OF THE AREA AS THE DIURNAL CU
DISSIPATE...WITH THE EASTERN U.P. HANGING ON THE LONGEST INTO THE
OVERNIGHT HOURS. WHILE THE CLEAR SKIES WILL PROMOTE RADIATIONAL
COOLING...THINKING THERE WILL BE ENOUGH MIXING FROM JUST ABOVE THE
SURFACE AND THE REMAINING PRESSURE GRADIENT TO KEEP LOWS FROM
GETTING AS COLD AS SEEN A FEW DAYS AGO ON THE CLEAR/CALM NIGHTS. BUT
WITH THE COLD AIR IN PLACE AND LITTLE REBOUND IN TEMPS TODAY...HAVE
LOWS IN THE TEENS AND TWENTIES BELOW ZERO FOR TONIGHT. WHEN COMBINED
WITH THE EXPECTED WINDS OF 4-8MPH TONIGHT...WIND CHILL VALUES WILL
REMAIN IN THE -25 TO -35 DEGREE RANGE THROUGH MONDAY MORNING. DO
HAVE A FEW AREAS WHERE WIND CHILLS WILL BE IN WARNING CRITERIA
(GENERALLY OVER IRON COUNTY)...BUT WITH WINDS IN THOSE AREAS ONLY
AROUND 5MPH OVERNIGHT...DIDN/T FEEL THAT THE WINDS WERE CLOSE ENOUGH
TO OUR 10MPH CRITERIA TO ISSUE THE WARNING. ALSO AM A LITTLE
CONCERNED WITH WIND CHILLS REACHING WARNING CRITERIA OVER THE
KEWEENAW PENINSULA...AS THEY HAVE BEEN BOUNCING BACK AND FORTH OVER
THE -35 CRITERIA LATE THIS MORNING AND INTO THE AFTERNOON. THIS WILL
LIKELY CONTINUE THROUGH MUCH OF THE NIGHT AS WINDS BACK AND THE
TIGHTEST GRADIENT PIVOTS OVER THAT AREA. EITHER WAY...IT WILL BE
VERY COLD ACROSS UPPER MICHIGAN TONIGHT INTO MONDAY MORNING.
OVERALL...MONDAY LOOKS TO BE QUIET ACROSS THE AREA AS THE HIGH
PRESSURE RIDGE DEPARTS. AFTER A SUNNY START TO THE DAY...MID-HIGH
CLOUDS WILL STREAM OVER THE AREA THROUGH THE AFTERNOON AHEAD OF A
COLD FRONT THAT WILL MOVE THROUGH THE AREA LATE MONDAY NIGHT. BUT
WITH ABUNDANT DRY AIR BETWEEN 900-700MB...EXPECT THE PRECIPITATION
TO STAY OFF TO THE WEST OF UPPER MICHIGAN THROUGH THE LATE
AFTERNOON. WINDS WILL GET GUSTY OUT OF THE SOUTHWEST DURING THE
AFTERNOON AND ESPECIALLY THE EVENING. THUS...ADDED PATCHY BLOWING
SNOW TO SOME AREAS OVER THE WEST DURING THE LATE AFTERNOON. WILL SEE
HIGHS REBOUND INTO THE SINGLE DIGITS AND A FEW LOWER TEENS ABOVE
ZERO TOMORROW...BUT WITH THE INCREASING WINDS IN THE AFTERNOON IT
WILL STILL FEEL VERY COLD.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 250 AM EST MON FEB 23 2015
TUESDAY THROUGH SUNDAY WILL BE MARKED BY BOOKEND LOW PRESSURE
SYSTEMS...WITH HIGH PRESSURE IN BETWEEN. THE FIRST AT 12Z TUESDAY
WILL BE SET UP FROM S HUDSON BAY THROUGH CENTRAL ONTARIO...AND
CENTRAL LAKE SUPERIOR...DRAGGING A COLD FRONT ACROSS THE W THIRD OF
THE CWA. THE FRONTAL BOUNDARY WILL SWIFTLY EXIT E...AND RESIDE FROM
JAMES BAY THRUOGH FAR SE LAKE SUPERIOR BY 18Z TUESDAY. 1-2 IN OF NEW
SNOW WILL BE POSSIBLE TUESDAY OVER MUCH OF THE CWA...WITH THE
HIGHEST VALUES FAR N AND E. WHILE WINDS ALOFT WILL BE DIMINISHING
FROM THE 40-50KT WINDS OVERNIGHT...SFC WINDS WILL BE STEADY TO ON
THE INCREASE. LOOK FOR WINDS OF 10-20KTS DURING THE DAY
TUESDAY...HIGHEST W AND ALONG LAKE SUPERIOR.
WILL BE INTERESTING TO SEE WHAT THE INCREASED SW WINDS TODAY-
TONIGHT...AND NW WINDS TUESDAY DO TO THE RELATIVLY THIN AND
FRACTURED ICE COVERING MUCH OF LAKE SUPERIOR. HOW IT PROGRESSES WILL
HAVE A LARGE IMPACT ON THE AREAL COVERAGE AND INTENSITY OF LAKE
EFFECT SNOW BANDS TUESDAY AFTERNOON THROUGH THURSDAY ON MAINLY NW TO
WNW WINDS.
SLOWLY FALLING INVERSION HEIGHTS TUESDAY NIGHT...AND THE DGZ GOING
AWAY AS MUCH COLDER AIR SLIDES IN ON THE NW WINDS WILL RESULT IN THE
RETURN OF SMALL SNOWFLAKES THAT WILL NOT ACCUMULATE TO MUCH BUT ARE
VERY AFFECTIVE AT REDUCING VIS. ANOTHER COLD ARCTIC ARIMASS WILL BE
ABLE TO SLIDE INTO THE REGION AS HIGH PRESSURE OVER MUCH OF THE W
HALF OF CANADA SLOWLY SINKS ACROSS S CENTRAL CANADA...THE N AND
CENTRAL PLAINS...AND THE UPPER GREAT LAKES BY THE END OF THE WORK
WEEK. LIGHT LES ON N TO WNW WINDS WILL BE THE RULE.
WIND CHILL VALUES WILL AGAIN FALL INTO THE -20 TO -30F RANGE LATE
TUESDAY NIGHT THROUGH WEDNESDAY MORNING. THAT 10MPH WIND PORTION OF
THE WIND CHILL ADVISORY SHOULD BE MET ACROSS MOST OF THE CWA...WITH
STRONGER NW WINDS NEARING 15MPH N CENTRAL AND E ALONG LAKE SUPERIOR.
THE APPARENT TEMPERATURE PORTION OF WIND CHILL ADVISORY CRITERIA IS
-25 TO -34F.
LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING MAY AGAIN BRING US
DOWN TO 20 TO NEAR 30 BELOW ZERO WIND CHILLS. HOWEVER...THE NW WINDS
SHOULD BE MUCH LIGHTER.
THURSDAY NIGHT-FRIDAY WILL BE A PERIOD OF MAINLY W TO WSW WINDS.
LAKE EFFECT SNOW SHOWERS SHOULD BE EITHER MIMIMAL OR NON-
EXISTANT...AND IMPACTING THE KEWEENAW PENINSULA AND RIGHT ALONG THE
LAKE SUPERIOR SHORELINE AROUND AND E OF GRAND MARAIS.
EXPECT DRY WEATHER SATURDAY...BUT INCREASING SW WINDS AND INVADING
CLOUDS FROM THE W. 850MB TEMPS WILL RISE TO AROUND -11 TO -13C
SATURDAY AND SUNDAY. SFC TEMPERATURES SHOULD REBOUND TO NEAR
20F...WHICH IS STILL AROUND 10 DEGREES BELOW NORMAL FOR THIS TIME OF
YEAR. SUNDAY SHOULD BE A COUPLE DEGREES WARMER...BUT FILLED WITH
MORE CLOUDS AND SNOW FOR THE ENTIRE CWA. EARLY INDICATIONS FROM THE
GFS POINT TO 2-5IN OF SNOW CWA WIDE LATE SATURDAY AFTERNOON THROUGH
SUNDAY EVENING. THE BEST MOISTURE LOOKS TO REMAIN TO OUR S AS UPPER
MI IS IN BETWEEN 2 LOWS /ONE OVER HUDSON BAY...AND ANOTHER EJECTING
OUT OF THE CENTRAL PLAINS/.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1220 AM EST MON FEB 23 2015
A STEADY WNW SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HI PRES
MOVING INTO THE OH RIVER VALLEY WL RESULT IN VFR CONDITIONS AT ALL 3
TAF SITES INTO THIS EVNG. ALTHOUGH THE W WIND WL UPSLOPE INTO CMX
EARLY THIS MRNG...THE UPSTREAM AIRMASS IS SO DRY AND LK SUP
SUFFICIENTLY ICE COVERED TO LIMIT THE POTENTIAL FOR LES OR EVEN MUCH
IN THE WAY OF LK CLDS. THE SW WINDS WL STRENGTHEN AND TURN GUSTY
THIS AFTN AS THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FNT APRCHG
FM THE NW. SN IN ADVANCE OF THIS FNT WL ARRIVE NW-SE LATE THIS EVNG.
DRY NATURE OF THE ANTECEDENT AIRMASS WL MAINTAIN VFR CONDITIONS
INITIALLY DESPITE THE THICKENING CLD COVER AND ARRIVING -SN. BEST
CHC FOR MVFR CONDITIONS BEFORE 24/06Z WL BE AT CMX...WHERE THE PCPN
WL ARRIVE EARLIEST.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 305 PM EST SUN FEB 22 2015
HIGH PRESSURE IN THE DAKOTAS WILL MOVES INTO THE MID MISSISSIPPI
VALLEY LATE TONIGHT AND MONDAY MORNING...WHILE SHIFTING A RIDGE
ACROSS THE UPPER GREAT LAKES REGION. THIS WILL LEAD TO WEAKENING
WINDS TONIGHT...BEFORE QUICKLY INCREASING OUT OF THE SOUTHWEST ON
MONDAY AFTERNOON AHEAD OF A LOW PRESSURE SYSTEM DROPPING SOUTHEAST
THROUGH NORTHERN ONTARIO. THIS WILL LEAD TO SOUTHWESTERLY GALES OF
35-40KTS OVER PORTIONS OF LAKE SUPERIOR MONDAY AFTERNOON/EVENING
AND HAVE ISSUED A GALE WARNING FOR MUCH OF WESTERN/CENTRAL LAKE
SUPERIOR FOR LATE MONDAY AFTERNOON AND MONDAY NIGHT. THEN AS A COLD
FRONT SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE MONDAY NIGHT INTO
TUESDAY MORNING AND SHIFT WINDS TO THE NORTHWEST. THERE MAY BE A FEW
GALE FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER
EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO
THE AREA WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY
LIGHT WINDS BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR
MIZ001>007-009>014-084-085.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR
LSZ266.
GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST
/6 AM CST/ TUESDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KF
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1221 AM EST MON FEB 23 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 305 PM EST SUN FEB 22 2015
A VERY COLD UPPER TROUGH IS SLIDING EAST ACROSS THE UPPER GREAT
LAKES REGION THIS AFTERNOON...WITH RAP ANALYZED 850MB TEMPS OF -29C
OVER WESTERN LAKE SUPERIOR. THIS HAS LED TO AFTERNOON TEMPERATURES
AROUND 25-30 DEGREES BELOW THE NORMAL HIGHS FOR THIS TIME OF YEAR
WITH 2PM TEMPERATURES RANGING FROM -10 AT KCMX TO 7 AT KMNM. THE
COLD AIR AND A FEW BREAKS IN THE ICE...OR AT LEAST AREAS OF THIN
ICE...HAS CONTINUED TO LEAD TO VERY THIN BANDS OF LAKE EFFECT OFF
LAKE SUPERIOR IN THE NORTHWEST WIND SNOW BELTS. WHILE THE BANDS HAVE
BEEN THIN...OBS AND WEBCAMS HAVE SHOWN THAT THEY CONTINUE TO BE
EFFICIENT AT REDUCING VISIBILITIES WITH ALL OF THE CLOUDY WELL BELOW
THE DGZ. THOSE VERY LOCALIZED LOWER VISIBILITIES HAVE ALSO BEEN
AIDED BY BLOWING SNOW FROM THE GUSTY NORTHWEST WINDS OF 15-30MPH.
MEANWHILE...A SURFACE HIGH IS CURRENTLY LOCATED OVER THE EASTERN
DAKOTAS AND AN ASSOCIATED SURFACE RIDGE IS NOSING INTO THE UPPER
GREAT LAKES.
THE HIGH WILL DROP SOUTHEAST INTO THE MID MISSISSIPPI VALLEY
TONIGHT...WHICH WILL PUSH A RIDGE ACROSS THE UPPER GREAT LAKES
REGION. THIS RIDGE WILL LEAD TO BACKING WINDS THROUGH THE
NIGHT...BECOMING SOUTHWESTERLY LATE TONIGHT OVER THE WEST AND MONDAY
MORNING OVER THE EAST. THESE BACKING WINDS...ALONG WITH INCREASING
SUBSIDENCE...WILL DIMINISH THE LAKE EFFECT POTENTIAL FROM THE
LIMITED HEATING FROM LAKE SUPERIOR. THUS...EXPECT SKIES TO BECOME
MOSTLY CLEAR THIS EVENING OVER MUCH OF THE AREA AS THE DIURNAL CU
DISSIPATE...WITH THE EASTERN U.P. HANGING ON THE LONGEST INTO THE
OVERNIGHT HOURS. WHILE THE CLEAR SKIES WILL PROMOTE RADIATIONAL
COOLING...THINKING THERE WILL BE ENOUGH MIXING FROM JUST ABOVE THE
SURFACE AND THE REMAINING PRESSURE GRADIENT TO KEEP LOWS FROM
GETTING AS COLD AS SEEN A FEW DAYS AGO ON THE CLEAR/CALM NIGHTS. BUT
WITH THE COLD AIR IN PLACE AND LITTLE REBOUND IN TEMPS TODAY...HAVE
LOWS IN THE TEENS AND TWENTIES BELOW ZERO FOR TONIGHT. WHEN COMBINED
WITH THE EXPECTED WINDS OF 4-8MPH TONIGHT...WIND CHILL VALUES WILL
REMAIN IN THE -25 TO -35 DEGREE RANGE THROUGH MONDAY MORNING. DO
HAVE A FEW AREAS WHERE WIND CHILLS WILL BE IN WARNING CRITERIA
(GENERALLY OVER IRON COUNTY)...BUT WITH WINDS IN THOSE AREAS ONLY
AROUND 5MPH OVERNIGHT...DIDN/T FEEL THAT THE WINDS WERE CLOSE ENOUGH
TO OUR 10MPH CRITERIA TO ISSUE THE WARNING. ALSO AM A LITTLE
CONCERNED WITH WIND CHILLS REACHING WARNING CRITERIA OVER THE
KEWEENAW PENINSULA...AS THEY HAVE BEEN BOUNCING BACK AND FORTH OVER
THE -35 CRITERIA LATE THIS MORNING AND INTO THE AFTERNOON. THIS WILL
LIKELY CONTINUE THROUGH MUCH OF THE NIGHT AS WINDS BACK AND THE
TIGHTEST GRADIENT PIVOTS OVER THAT AREA. EITHER WAY...IT WILL BE
VERY COLD ACROSS UPPER MICHIGAN TONIGHT INTO MONDAY MORNING.
OVERALL...MONDAY LOOKS TO BE QUIET ACROSS THE AREA AS THE HIGH
PRESSURE RIDGE DEPARTS. AFTER A SUNNY START TO THE DAY...MID-HIGH
CLOUDS WILL STREAM OVER THE AREA THROUGH THE AFTERNOON AHEAD OF A
COLD FRONT THAT WILL MOVE THROUGH THE AREA LATE MONDAY NIGHT. BUT
WITH ABUNDANT DRY AIR BETWEEN 900-700MB...EXPECT THE PRECIPITATION
TO STAY OFF TO THE WEST OF UPPER MICHIGAN THROUGH THE LATE
AFTERNOON. WINDS WILL GET GUSTY OUT OF THE SOUTHWEST DURING THE
AFTERNOON AND ESPECIALLY THE EVENING. THUS...ADDED PATCHY BLOWING
SNOW TO SOME AREAS OVER THE WEST DURING THE LATE AFTERNOON. WILL SEE
HIGHS REBOUND INTO THE SINGLE DIGITS AND A FEW LOWER TEENS ABOVE
ZERO TOMORROW...BUT WITH THE INCREASING WINDS IN THE AFTERNOON IT
WILL STILL FEEL VERY COLD.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 356 PM EST SUN FEB 22 2015
PATTERN OF HIGH AMPLITUDE UPR RIDGE OVER THE ERN PACIFIC/WRN
NAMERICA AND DEEP TROF OVER CENTRAL AND ERN NAMERICA WL PERSIST THRU
MUCH OF THE WEEK...RESULTING IN A CONTINUED NW FLOW ALOFT THAT WL
BRING ARCTIC SURGES INTO THE UPPER LKS THRU MID WEEK. TOWARD THE END
OF THE WEEK THOUGH...FALLING HGTS OVER THE W WL ALLOW FOR A MORE
ZONAL FLOW AND SOME AIRMASS MODERATION. BUT WITH DRY HI PRES FCST TO
BE DOMINATING...LOW TEMPS MAY STILL BE QUITE COLD DESPITE THE MORE
SEASONABLE H85 AND DAYTIME TEMPS.
MON NGT/TUE...SHRTWV AND ACCOMPANYING SFC LOW DESCENDING SE INTO FAR
NW ONTARIO BY MON EVNG ARE FCST TO SLIDE JUST NE OF LK SUP DURING
THIS TIME...WITH ATTENDANT COLD FROPA MOVING OVER UPR MI LATE MON
NIGHT AND TUE MRNG. SOME LIGHT SN IN THE WAA/ISENTROPIC ASCENT
PATTERN AHEAD OF THIS DISTURBANCE WL OVERSPREAD UPR MI FM THE NW ON
MON NGT AND PERSIST INTO TUE MRNG BEFORE THE COLD FROPA. SINCE THE
MSTR INFLOW WL BE RATHER UNIMPRESSIVE...WITH MIXING RATIOS OF 1-1.5
G/KG FCST ON 280K ISENTROPIC SFC...AND VERY DRY ANTECEDENT AIRMASS
IN PLACE WHICH WL TAKE TIME TO MOISTEN...ACCOMPANYING SN ACCUMS
SHOULD BE LIMITED TO NO MORE THAN 1 TO 2 INCHES FOR MOST OF CWA WITH
MAYBE A FEW LOCATIONS SEEING 3-4 INCHES FAR EAST AND OVER TIP OF
KEWEENAW...WHERE HIGHER POPS/QPF WL BE MAINTAINED CLOSER TO THE
SHRTWV TRACK...LONGER DURATION OF ISENTROPIC ASCENT AND AREA OF
STRONGER DEEP LAYER Q-VECT CONV. ALTHOUGH MODELS SNDGS INDICATE THE
DGZ TO BE RATHER DEEP AND INTERSECTING MUCH OF THE ASSOCIATED
UVV...STRONG WINDS THROUGH THE MUCH OF THE LAYER MIGHT BREAK UP THE
DENDRITES TO A CERTAIN EXTENT. BUT AT SAME TIME...THE SMALLER FLAKES
WOULD BE MORE EFFICIENT AT RESTRICTING VSBY WHILE BEING BLOWN ABOUT
BY THE GUSTY VEERING WINDS OCCURRING UNDER THE TIGHT PRES GRADIENT
AHEAD OF THE COLD FRONT. WITH H85 THERMAL RDG OVER UPR MI ON MON NGT
AND THE GUSTY WINDS...EXPECT RELATIVELY HIGH MIN TEMPS. WSHFT TO THE
NW FOLLOWING THE TUE MORNING COLD FROPA WL DRAG ANOTHER ARCTIC
AIRMASS BACK INTO THE CWA IN THE AFTN...DROPPING H85 TEMPS TO -20C
OR COLDER AGAIN BY 00Z WED AND ALLOWING FOR AT LEAST SCATTERED LES
TO DEVELOP IN WHATEVER BREAKS THERE ARE IN LAKE SUPERIOR ICE COVER.
TUE NGT INTO WED NIGHT...MEDIUM RANGE GUIDANCE FCSTS H85 TEMPS TO
FALL AS LO AS -28C TO -30C AROUND 12Z WED IN COLD NNW FLOW AHEAD OF
THE NEXT CANADIAN HIGH PRES BUILDING TOWARD THE NRN PLAINS. THERE
MAY BE SOME LES OFF BREAKS IN THE EXTENSIVE ICE COVER...BUT THE
BIGGEST STORY WL BE WIND CHILLS AT LEAST REACHING INTO ADVY CRITERIA
TUE NIGHT INTO WED MORNING AS 950 MB WINDS ARE FCST AOA 30 KTS
DURING THE DESTABILIZING PERIOD OF CAA THAT WL DROP MIN TEMPS BLO
ZERO AGAIN. AFTER HIGHS POSSIBLY STRUGGLING TO REACH ABV ZERO OVER
THE NW CWA ON WED...ANOTHER BITTER COLD NIGHT IS IN STORE FOR WED
NIGHT WITH DOUBLE DIGIT BLO ZERO READINGS LIKELY OVER A GOOD
PORTION OF THE CWA.
THU INTO SUN...THE ARCTIC HI OVER SCENTRAL CANADA ON WED IS FCST TO
DRIFT SLOWLY TO THE ESE REACHING THE NRN PLAINS ON THU...AND THE MID
MS VALLEY AND LOWER GREAT LAKES/OH RIVER VALLEY ON FRI BEFORE
REACHING THE MID-ATLANTIC STATES ON SAT UNDER A PATTERN OF SLOWLY
RISING 5H HGTS IN THE GREAT LAKES DOWNSTREAM OF TROFFING OVER WRN
NAMERICA. THE RESULT WL BE A PERIOD OF MAINLY DRY WX UNDER DOMINANT
SFC HIGH PRES RIDGE. ALTHOUGH THERE MAY BE SOME LES MAINLY E OF
MARQUETTE INTO THU WHILE THE LLVL FLOW IS STILL NW...BACKING WINDS
TOWARD THE W AND THEN SW WL SHIFT ANY REMAINING LES OUT INTO LK SUP
BY LATE THU NIGHT. H85 TEMPS ARE FCST TO MODERATE TO -15C TO -17C BY
FRI/SAT...ALLOWING DAYTIME TEMPS TO WARM NEAR 20F UNDER A GOOD DEAL
OF SUNSHINE. HOWEVER...STILL EXPECT VERY COLD OVERNIGHT TEMPS (BLO
ZERO) AT LEAST THU NIGHT AND FRI NIGHT AS FCST PWAT IS LOWER THAN
.10 INCH UNDER LIGHT WINDS. MORE CLDS AND LIGHT MAY ARRIVE SAT NIGHT
INTO SUN IN ADVANCE OF THE NEXT APPROACHING LOW PRES TROF.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1220 AM EST MON FEB 23 2015
A STEADY WNW SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HI PRES
MOVING INTO THE OH RIVER VALLEY WL RESULT IN VFR CONDITIONS AT ALL 3
TAF SITES INTO THIS EVNG. ALTHOUGH THE W WIND WL UPSLOPE INTO CMX
EARLY THIS MRNG...THE UPSTREAM AIRMASS IS SO DRY AND LK SUP
SUFFICIENTLY ICE COVERED TO LIMIT THE POTENTIAL FOR LES OR EVEN MUCH
IN THE WAY OF LK CLDS. THE SW WINDS WL STRENGTHEN AND TURN GUSTY
THIS AFTN AS THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FNT APRCHG
FM THE NW. SN IN ADVANCE OF THIS FNT WL ARRIVE NW-SE LATE THIS EVNG.
DRY NATURE OF THE ANTECEDENT AIRMASS WL MAINTAIN VFR CONDITIONS
INITIALLY DESPITE THE THICKENING CLD COVER AND ARRIVING -SN. BEST
CHC FOR MVFR CONDITIONS BEFORE 24/06Z WL BE AT CMX...WHERE THE PCPN
WL ARRIVE EARLIEST.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 305 PM EST SUN FEB 22 2015
HIGH PRESSURE IN THE DAKOTAS WILL MOVES INTO THE MID MISSISSIPPI
VALLEY LATE TONIGHT AND MONDAY MORNING...WHILE SHIFTING A RIDGE
ACROSS THE UPPER GREAT LAKES REGION. THIS WILL LEAD TO WEAKENING
WINDS TONIGHT...BEFORE QUICKLY INCREASING OUT OF THE SOUTHWEST ON
MONDAY AFTERNOON AHEAD OF A LOW PRESSURE SYSTEM DROPPING SOUTHEAST
THROUGH NORTHERN ONTARIO. THIS WILL LEAD TO SOUTHWESTERLY GALES OF
35-40KTS OVER PORTIONS OF LAKE SUPERIOR MONDAY AFTERNOON/EVENING
AND HAVE ISSUED A GALE WARNING FOR MUCH OF WESTERN/CENTRAL LAKE
SUPERIOR FOR LATE MONDAY AFTERNOON AND MONDAY NIGHT. THEN AS A COLD
FRONT SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE MONDAY NIGHT INTO
TUESDAY MORNING AND SHIFT WINDS TO THE NORTHWEST. THERE MAY BE A FEW
GALE FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER
EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO
THE AREA WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY
LIGHT WINDS BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR
MIZ001>007-009>014-084-085.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR
LSZ266.
GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST
/6 AM CST/ TUESDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
244 PM CST MON FEB 23 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 230 PM CST MON FEB 23 2015
A STRONG PRESSURE GRADIENT TONIGHT WILL KEEP TEMPS FROM FALLING
MUCH...AND WILL LIKELY HOLD AND BEGIN TO RISE OVERNIGHT. TEMPERATURES
ACROSS SOUTHERN MANITOBA ARE IN THE MID/UPPER 20S AHEAD OF A
STRONG WARM FRONT MOVING INTO THE DAKOTAS THIS AFTN. THESE WARMER
TEMPS WILL LIKELY ADVECT SE AND SPREAD ACROSS WESTERN MN DURING
THE EVENING...AND ACROSS SOUTHERN MN AFT MIDNIGHT. IN
ADDITION...STRONG WAA AHEAD OF THIS FRONT WILL LEAD TO SOME -SN
DURING THE EVENING...ESPECIALLY ACROSS CENTRAL AND NORTHERN MN.
HOWEVER...THE INITIAL DRY AIR MASS IN SOUTHERN MN WILL LIKELY
DISSIPATE ANY PRECIPITATION THAT FALLS UNTIL WELL AFT MIDNIGHT AS
ANOTHER STRONGER SHRTWV ACROSS CENTRAL MANITOBA RACING SE OVER
MN/WI BY MORNING. LATEST WV IMAGERY SHOWS THIS SHRTWV FAIRLY
STRONG...SO I WOULD NOT BE SURPRISE TO SEE SOME ACCUMULATING
SNOWFALL IN OUR NE CWA BY LATE TUESDAY MORNING. HOW FAR SW THIS
AREA OF LIGHT SNOW OCCURS IS DEPENDENT ON THE DEPTH OF THE
MOISTURE AND LOCATION OF THE SHRTWV. BY LATE MORNING...A COLD
FRONT WOULD HAVE MOVED ACROSS MOST OF MN...CAUSING TEMPS DURING
THE AFTN TO SLOWLY FALL. GUSTY WINDS WILL ALSO CONTINUE THRU THE
AFTN AS STRONG CAA DEVELOPS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 230 PM CST MON FEB 23 2015
NO SIGNIFICANT CHANGES TO THE EXTENDED FORECAST. AS ALLUDED TO IN THE
PREVIOUS DISCUSSION...COLD WEATHER IS A CERTAINTY...WITH LINGERING
LIGHT SNOW REMAINING POSSIBLE...BUT NOT LIKELY ACROSS CENTRAL MN AND
WESTERN WI.
THERE ARE TWO MAIN CHANCES FOR PRECIPITATION. THE FIRST COMES
WEDNESDAY AS A POTENT PV ANOMALY DIVES ALONG THE MISSOURI RIVER
VALLEY AND WILL PRODUCE A QUICK BURST OF MODERATE TO HEAVY SNOWFALL.
THE BULLSEYE OF QPF MATCHES UP WILL WITH THE H850 THETA_E
ADVECTION...BUT THIS FORCING REMAINS SOUTHWEST OF THE CWA. SO...LIGHT
SNOW SHOULD REMAIN CONFINED SOUTH AND WEST OF THE UPPER MINNESOTA
RIVER VALLEY.
THIS SYSTEM WILL BE FOLLOWED BY ANOTHER ARCTIC HIGH WITH COLD
TEMPERATURES AND CLEAR SKIES. THIS HIGH WILL SHIFT EASTWARD AS AN
UPPER LEVEL TROUGH CARVES OUT ACROSS THE 4-CORNERS REGION...WITH
DOWNSTREAM SOUTHWEST FLOW DEVELOPING ACROSS THE CENTRAL CONUS. THE
NORTHERN EXTEND OF THIS SOUTHWEST FLOW WILL DETERMINE THE STORM
TRACK...AND POTENTIAL FOR SNOW OVER THE WEEKEND. AT THIS TIME...DID
NOT STRAY FROM A BLENDED GUIDANCE...WHICH HAS THE HEAVIEST SNOW
CLOSER TO THE I-80 CORRIDOR THAN THE I-90 CORRIDOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1125 AM CST MON FEB 23 2015
GUSTY SW WINDS WILL BE THE MAIN CONCERN THRU 00Z AS THE PRESSURE
GRADIENT STRENGTHENS. OTHERWISE...VFR CONDS WITH -SN POSSIBLE IN
KAXN AFT 01Z BASED ON THE LATEST HRRR REFLECTIVITY RUN.
ELSEWHERE...THE MAIN CHC OF -SN WILL HOLD OFF UNTIL AFT 06Z...WITH
THE BEST TIME FRAME BETWEEN 9-15Z WHERE BOTH VSBY/CIGS DROP INTO
THE MVFR RANGE. A PERIOD OF IFR VSBY IN -SN IS POSSIBLE IN EC
MN/WC WI IF THE WX SYSTEM MOVING INTO FAR NW MN STRENGTHENS A BIT
MORE. WILL CONTINUE TO MONITOR UPSTREAM OBS IN NW MN AND SEE IF
AMD ARE NEEDED THIS AFTN. WINDS WILL REMAIN GUSTY THRU THE
NIGHT/MORNING HRS...WITH A SHIFT TO THE WEST/NW BY MORNING.
KMSP...
MAIN CONCERN IS THE CROSSWIND COMPONENT THIS AFTN WITH WINDS
POSSIBLY GUSTING OVER 25 KTS AT TIMES /230-210 DEGREES/. 30 KT
GUSTS ARE NOT EXPECTED...BUT WILL MONITOR IF CONDS CHG.
OTHERWISE...CIGS WILL LOWER TONIGHT TO LOW END VFR WITH A CHC OF
-SN AFT 9Z. MVFR VSBY IN -SN IS POSSIBLE BETWEEN 9-15Z. CONFIDENCE
REMAINS LOW ON VSBYS LOWER THAN 3SM IN -SN. WINDS WILL REMAIN
GUSTY OVERNIGHT...AND BACK TO THE WEST AFT 9Z...AND TO THE NW BY
12-15Z AS THE COLD FRONT MOVES THRU.
/OUTLOOK FOR KMSP/
WED...VFR. WINDS NNW 10 KTS.
THU...VFR. WINDS NW 5-10 KTS.
FRI...VFR. WINDS WSW 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JLT
LONG TERM...JRB
AVIATION...JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1128 AM CST MON FEB 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM CST MON FEB 23 2015
THE PRIMARY CONCERN IN THE SHORT TERM WILL BE WIND CHILLS EARLY THIS
MORNING...AND THEN ATTENTION SHIFTS TO THE CHANCE FOR LIGHT SNOW
LATE TONIGHT.
CLEAR SKIES AND SURFACE HIGH PRESSURE HAVE CONTRIBUTED TO QUITE A
COLD NIGHT ACROSS THE AREA...WITH WIDESPREAD TEMPERATURES RANGING
FROM 10 BELOW TO 20 BELOW ACROSS THE FORECAST AREA. THE COMBINATION
OF THESE FRIGID TEMPERATURES WITH A 5-7 MPH WIND HAS YIELDED WIND
CHILL READINGS FROM 25 BELOW TO 35 BELOW ACROSS THE MAJORITY OF THE
FORECAST AREA. THE ONE EXCEPTION IS ALONG THE MN RIVER
VALLEY...WHERE LIGHTER WINDS IN CLOSER PROXIMITY TO THE HIGH
PRESSURE RIDGE AXIS HAVE MADE FOR SLIGHTLY WARMER WIND CHILLS IN THE
15 TO 20 BELOW RANGE. WINDS ARE FORECAST TO INCREASE A COUPLE KNOTS
AROUND DAYBREAK HOWEVER...WHICH WOULD PUSH APPARENT TEMPERATURES TO
AROUND THE 25 BELOW MARK WHERE THEY ARE NOT CURRENTLY MEETING
ADVISORY CRITERIA. WILL THEREFORE KEEP THE CURRENT ADVISORY THAT
ENCOMPASSES THE ENTIRE CWA IN TACT THROUGH 10 AM CST.
THE AFOREMENTIONED INCREASE IN WINDS WILL ENSUE THROUGH THE MORNING
HOURS...WITH THE SOUTHWESTERLY DIRECTIONAL COMPONENT YIELDING A
MODERATION IN TEMPERATURES FOR WEST CENTRAL AND SOUTHWEST MN. HIGHS
THERE WILL CLIMB WELL INTO THE 20S...WHILE CENTRAL MN AND WEST
CENTRAL WI EXPERIENCE COOLER HIGHS IN THE 10 TO 20 DEGREE RANGE.
HIGH CLOUDS INCREASE THIS AFTERNOON AS A SHORTWAVE APPROACHES FROM
CANADA. DEEPER SATURATION AND WEAK LIFT ARRIVE BETWEEN 06Z AND 09Z
TUESDAY INTO CENTRAL MN/WI. HAVE INCLUDED 20-30 POPS GENERALLY ALONG
AND NORTH OF THE INTERSTATE 94 CORRIDOR...WHERE A COUPLE TENTHS TO A
HALF INCH NEW SNOW ON THE GROUND APPEARS POSSIBLE BY DAYBREAK
TUESDAY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 412 AM CST MON FEB 23 2015
DURING THE EXTENDED...WE WILL CONTINUE TO ADD ON TO OUR TEMPERATURE
DEPARTURE FOR THE MONTH...WHICH SAW ANOTHER 9 TENTHS OF A DEGREE
ADDED ON TO THE DEPARTURE FROM NORMAL AFTER YESTERDAYS
AVERAGE TEMPERATURE DEPARTURE OF 27 DEGREES BELOW NORMAL. ON THE
MONTH...MSP NOW SITS AT 8.1 DEGREES BELOW NORMAL AND WILL LIKELY
FINISH CLOSE TO 10 DEGREES BELOW NORMAL AFTER WE GET 3 MORE DAYS
WEDNESDAY...THURSDAY...AND FRIDAY WHERE THE AVERAGE TEMPERATURE
DEPARTURE SHOULD BE NEAR OR GREATER THAN 20 DEGREES BELOW NORMAL.
THE REASON THE COLD LOOKS TO STAY...IS THE LARGE SCALE WEATHER
PATTERN DOES NOT LOOK TO CHANGE ALL THAT MUCH...WITH NOTHING MORE
THAN A WESTWARD SHIFT IN THE RIDGE/TROUGH/RIDGE PATTERN THAT HAS
BEEN IN PLACE PRETTY MUCH ALL OF FEBRUARY. WITHIN THIS
PATTERN...WE WILL BE SCRAPPED BY A STRONG CLIPPER GOING INTO THE
WRN GREAT LAKES TUESDAY AND ANOTHER DIVING SOUTH ACROSS THE
DAKOTAS ON WEDNESDAY. THE BEST SHOT AT SEEING ANY MEANINGFUL SNOW
LOOKS TO COME THIS WEEKEND AS SOUTHERN STREAM ENERGY GETS PULLED
INTO THE NORTHERN STREAM.
A FEW MINOR CHANGES WERE NEEDED TO THE FORECAST TUESDAY AND
WEDNESDAY. HIGHS WERE KNOCKED BACK A COUPLE OF DEGREES ON TUESDAY AS
WE WILL BE FIRMLY WITHIN STRONG CAA IN THE WAKE OF THE COLD FRONT
COMING THROUGH TONIGHT. THIS WILL LEAD TO GRADUALLY FALLING
TEMPERATURES DURING THE AFTERNOON ON TUESDAY AS NW WINDS LIKELY GUST
TO BETWEEN 30 AND 40 MPH. ALSO REMOVED THE POPS ACROSS SW MN ON
TUESDAY AS THEY WILL BE UNDER THE INFLUENCE OF SUBSIDENCE WITHIN THE
RIGHT EXIT REGION OF A NORTHWESTERLY JET STREAK. RAISED THE CHANCE
POPS A BIT TUESDAY MORNING IN THE EAST WHERE THE SNOW ARRIVING THERE
TONIGHT WILL BE EXITING DURING THE MORNING. LIKE MOST OF THE SYSTEMS
WE HAVE SEEN IN THIS PATTERN...THIS WILL ONLY RESULT IN AROUND A
HALF INCH OF SNOW IN WRN WI. FOR WEDNESDAY...MODELS CONTINUE TO
PAINT A SWATH OF 2-4 INCHES OF SNOW GOING FROM WESTERN NODAK TOWARD
WESTERN IOWA. THE BRUNT OF THIS WAVE STILL LOOKS TO REMAIN SW OF THE
MPX AREA...THOUGH THE ECMWF/SREF/NAM ALL SHOW THE NE EDGE OF THE
SNOW BAND COMING ABOUT AS FAR NE AS THE UPPER MN RIVER VALLEY...SO
ADDED SOME CHANCE POPS SW OF THE MN RIVER TO ACCOUNT FOR THAT. STILL
NOT CONVINCED WE WILL SEE SNOW IN THE MPX CWA WITH THIS SYSTEM AS
NORTHERLY LOW LEVELS WINDS WILL RESULT IN DRY AIR UNDERCUTTING THIS
PRECIP SHIELD...WHICH IS THE SCENARIO THE 23.00 AND 23.06 GFS SHOWS
PLAYING OUT.
BESIDE THE LIGHT SNOW IN THE SW...THIS HIGH WILL BRING US ANOTHER
STINT IN ARCTIC AIR TUESDAY NIGHT THROUGH THURSDAY NIGHT.
HOWEVER...IT WILL NOT BE QUITE AS COLD AS WHAT WE JUST EXPERIENCED
SUNDAY...AS H85 TEMPS WILL BE ABOUT 5C WARMER THAN THEY WERE OVER
THE WEEKEND. STILL...HIGHS ON THURSDAY WILL BE MOSTLY IN THE SINGLE
DIGITS...WITH DOUBLE DIGIT BELOW ZERO LOWS LIKELY THURSDAY AND
FRIDAY MORNINGS ACROSS CENTRAL MN INTO WISCONSIN. OF COURSE THIS COLD
MEANS WE WILL HAVE TO BE ON THE LOOKOUT FOR MORE WIND CHILL ISSUES
AND WEDNESDAY NIGHT INTO THURSDAY MORNING IS STILL LOOKING TO BRING
US ANOTHER ROUND OF WIND CHILL ADVISORY WORTHY APPARENT TEMPERATURES
ACROSS CENTRAL MN.
FOR THE WEEKEND...THE ECMWF AND GFS CONTINUE TO SHOW A PLOWABLE
SNOWFALL HITTING THE SE THIRD OR SO OF THE MPX CWA. THE MAIN
DIFFERENCE BETWEEN THE ECMWF AND GFS IS ONE OF TIMING...WITH THE
ECMWF BEING ABOUT 12 HOURS BEHIND THE GFS. OTHERWISE...THEY BOTH
SHOW A DEEP TROUGH/NEARLY CLOSED UPPER LOW DEVELOPING OVER THE 4
CORNERS REGION BY SATURDAY...WITH A PIECE OF THIS ENERGY GETTING
PULLED NE INTO THE GREAT LAKES BY EARLY NEXT WEEK BY A POSITIVELY
TILTED NORTHERN STREAM TROUGH WORKING ACROSS SRN CANADA. HAVE
INCREASED POPS INTO THE 40S FOR THE SE CWA SATURDAY NIGHT AND
SUNDAY. ALTHOUGH IT IS LOOKING INCREASINGLY LIKELY THAT WE WILL
START MARCH WITH SHOVEL WORTHY SNOW...MODELS TRADITIONALLY STRUGGLE
WITH PHASING SYSTEMS SUCH AS THIS MORE THAN 3 OR 4 DAYS OUT...SO I
WOULD NOT GET YOUR HOPES UP TOO MUCH FOR SEEING MEASURABLE UNTIL THE
FORECAST LOOKS LIKE THIS TUESDAY OR WEDNESDAY AND BEYOND.
ON THE SNOW NOTE...THE REST OF FEBRUARY LOOKS TO GO OFF MOSTLY SNOW
FREE...BRINGING TO AN END ONE OF THE LEAST SNOWIEST METEOROLOGICAL
WINTERS WE HAVE SEEN IN TWO DECADES. FOR DEC/JAN/FEB...THE 15.6" OF
SNOW SO FAR AT MSP AND THE 16.6" AT EAU ARE THE LEAST BOTH LOCATIONS
HAVE SEEN SINCE THE WINTER OF 1994-95...WHILE THE PALTRY 9" OBSERVED
SO FAR THIS METEOROLOGICAL WINTER AT STC IS THE LEAST SINCE 1986-87.
OF COURSE WINTER IN MINNESOTA AND WISCONSIN DOES NOT END WITH
FEBRUARY...BUT IT WILL TAKE QUITE THE SPRING RALLY FOR US TO GET OUR
SEASONAL SNOWFALL TOTALS UP ANYWHERE NEAR OUR NORMAL OF 50 TO 55
INCHES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1125 AM CST MON FEB 23 2015
GUSTY SW WINDS WILL BE THE MAIN CONCERN THRU 00Z AS THE PRESSURE
GRADIENT STRENGTHENS. OTHERWISE...VFR CONDS WITH -SN POSSIBLE IN
KAXN AFT 01Z BASED ON THE LATEST HRRR REFLECTIVITY RUN.
ELSEWHERE...THE MAIN CHC OF -SN WILL HOLD OFF UNTIL AFT 06Z...WITH
THE BEST TIME FRAME BETWEEN 9-15Z WHERE BOTH VSBY/CIGS DROP INTO
THE MVFR RANGE. A PERIOD OF IFR VSBY IN -SN IS POSSIBLE IN EC
MN/WC WI IF THE WX SYSTEM MOVING INTO FAR NW MN STRENGTHENS A BIT
MORE. WILL CONTINUE TO MONITOR UPSTREAM OBS IN NW MN AND SEE IF
AMD ARE NEEDED THIS AFTN. WINDS WILL REMAIN GUSTY THRU THE
NIGHT/MORNING HRS...WITH A SHIFT TO THE WEST/NW BY MORNING.
KMSP...
MAIN CONCERN IS THE CROSSWIND COMPONENT THIS AFTN WITH WINDS
POSSIBLY GUSTING OVER 25 KTS AT TIMES /230-210 DEGREES/. 30 KT
GUSTS ARE NOT EXPECTED...BUT WILL MONITOR IF CONDS CHG.
OTHERWISE...CIGS WILL LOWER TONIGHT TO LOW END VFR WITH A CHC OF
-SN AFT 9Z. MVFR VSBY IN -SN IS POSSIBLE BETWEEN 9-15Z. CONFIDENCE
REMAINS LOW ON VSBYS LOWER THAN 3SM IN -SN. WINDS WILL REMAIN
GUSTY OVERNIGHT...AND BACK TO THE WEST AFT 9Z...AND TO THE NW BY
12-15Z AS THE COLD FRONT MOVES THRU.
/OUTLOOK FOR KMSP/
WED...VFR. WINDS NNW 10 KTS.
THU...VFR. WINDS NW 5-10 KTS.
FRI...VFR. WINDS WSW 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...LS
LONG TERM...MPG
AVIATION...JLT
AREA FORECAST DISCUSSION
NWS BUFFALO NY
728 PM EST TUE FEB 24 2015
.SYNOPSIS...
A MID-LEVEL SHORTWAVE AND SURFACE COLD FRONT WILL MOVE ACROSS THE
LOWER GREAT LAKES TONIGHT BRINGING THE NEXT ROUND OF ACCUMULATING
SNOW SHOWERS. ONLY AN INCH OR TWO IS EXPECTED. COLDER AIR IN THE
WAKE OF THE FRONT WILL HOLD TEMPERATURES AT LEAST 20 DEGREES BELOW
NORMAL FOR WEDNESDAY AND THURSDAY...WITH LAKE EFFECT SNOWS BRINGING
A FEW MORE INCHES OF SNOW EAST OF LAKE ONTARIO.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
CLOUDS ARE INCREASING ACROSS WESTERN AND NORTH CENTRAL NEW YORK THIS
AFTERNOON AHEAD OF THE NEXT MID-LEVEL SHORTWAVE AND ARCTIC COLD FRONT
APPROACHING FROM THE CENTRAL GREAT LAKES. SURFACE ANALYSIS PLACES
THE PARENT LOW OVER THE SOUTHERN TIP OF JAMES BAY WITH THE FRONT
EXTENDING SOUTHWEST ACROSS NORTHERN LOWER MICHIGAN TO NEAR CHICAGO
WHILE THE MID-LEVEL SHORTWAVE IS NOW SHIFTING JUST EAST OF MICHIGAN
AS OBSERVED ON REGIONAL RADAR BY A BAND OF SNOW. THE LEADING
SHORTWAVE WILL BRING AN INITIAL PERIOD OF SNOW SHOWERS THIS EVENING
WITH THE COLD FRONT CONTINUING TO PROVIDE SUFFICIENT LIFT FOR SNOW
SHOWERS OVERNIGHT. MESOSCALE MODELS INCLUDING THE HRRR AND REGIONAL
GEM MODEL BRING IN SNOW SHOWERS ACROSS FAR WESTERN NEW YORK ALONG
THE SHORTWAVE TROUGH BEGINNING AROUND 7PM SHIFTING EAST TO
NORTH-CENTRAL NEW YORK BY MIDNIGHT. ANOTHER PERIOD OF SNOW SHOWERS
IS EXPECTED ALONG AND AHEAD OF THE COLD FRONT OVERNIGHT.
WHILE MOST LOCATIONS SHOULD PICK UP A FRESH HALF TO ONE INCH
OVERNIGHT SOME UPSLOPING ACROSS THE CHAUTAUQUA RIDGE TO THE BOSTON
HILLS AND OVER THE TUG HILL COULD BRING UP TO TWO INCHES. THE COLD
AIR MASS LOOKS TO SUPPORT SNOW RATIO OVERNIGHT NEAR 20:1.
TEMPERATURES AHEAD OF THE COLD FRONT WILL HANG IN THE TEENS TONIGHT
THEN DROP TO NEAR 10 DEGREES BEHIND THE FRONT.
THE COLD FRONT WILL PUSH EAST ACROSS NEW YORK WEDNESDAY MORNING WITH
LINGERING SNOW SHOWERS TAPERING OFF ACROSS THE SOUTHERN TIER AND
NORTH COUNTY. THE COLDER WESTERLY FLOW BEHIND THE FRONT WILL KICK
OFF SOME LAKE EFFECT SNOW SHOWERS EAST OF LAKE ONTARIO THROUGH THE
DAY WEDNESDAY INTO WEDNESDAY EVENING. THE 270-280 FLOW SHOULD KEEP
THE SNOW FOCUSED ACROSS MAINLY NORTHERN OSWEGO COUNTY AND FAR
SOUTHWESTERN LEWIS COUNTY ACROSS THE TUG HILL. THE LIMITED PERIOD OF
ENHANCED EQUILIBRIUM HEIGHTS UP TO 10KFT DURING THE AFTERNOON AND
PRESENT ICE COVER AND SLUSH OVER THE EASTERN END OF THE LAKE SHOULD
KEEP SNOW TOTALS LIMITED TO THE 3-6 INCH RANGE WITH THE HIGHER END
AMOUNTS FOCUSED ACROSS THE TUG HILL. A LAKE EFFECT SNOW ADVISORY HAS
BEEN ISSUED TO COVER FOR THIS SNOW BAND. OUTSIDE OF THE LAKE EFFECT
SNOW TEMPERATURES WILL FALL THROUGH THE DAY INTO THE SINGLE DIGITS
BEHIND THE FRONT.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
LAKE EFFECT SNOW SHOULD BE ONGOING EAST OF LAKE ONTARIO WEDNESDAY
EVENING. BY THIS TIME WE SHOULD KNOW HOW MUCH ICE ON THE LAKE WILL
LIMIT LAKE EFFECT SNOW...WITH LATEST VISIBLE SATELLITE SHOWING
SIGNIFICANT PATCHES BUT ALSO SIGNIFICANT BREAKS IN THE ICE COVERAGE.
TYPICALLY WHEN THIS HAPPENS ON LAKE ERIE THESE BREAKS ARE AMPLE FOR
A LAKE RESPONSE...WHICH CAN OFTEN BE UNDERDONE BY MODEL QPF
DEPENDING ON THE ICE COVERAGE IN THE MODEL. WINDS WILL SHIFT FROM
THE WEST TO NORTHWEST WEDNESDAY EVENING WHICH WILL PUSH WHATEVER
LAKE EFFECT BAND THERE IS QUICKLY SOUTHWARD LATE WEDNESDAY EVENING.
OSWEGO COUNTY STILL COULD PICK UP ANOTHER INCH OR TWO WEDNESDAY
EVENING BEFORE THE BAND SHIFTS SOUTH AND BECOMES LESS ORGANIZED.
THIS LESS ORGANIZED BAND MAY BRING AN INCH SOUTH OF LAKE ONTARIO
FROM WEAK MULTIPLE BANDS LATE WEDNESDAY NIGHT.
A WEAK MID-LEVEL TROUGH WILL APPROACH THE REGION ON THURSDAY WHICH
WILL BRING SOME MID LEVEL CLOUDS AND POSSIBLY SOME LIGHT SNOW OR
FLURRIES TO ALL AREAS. ACCUMULATIONS FROM THIS SHOULD BE VERY LIGHT
(THINK DUSTING). THE ONLY EXCEPTION IS ACROSS THE NIAGARA
FRONTIER...WHERE A NORTHEASTERLY FLOW MAY TAKE ADVANTAGE OF THE LIMITED
OPEN WATERS ON LAKE ONTARIO. THIS COMBINED WITH SYNOPTIC MOISTURE
MAY BE ENOUGH TO BRING AN INCH OR TWO ON THURSDAY.
STRONG SURFACE HIGH PRESSURE ACROSS THE PLAINS STATES WILL RIDGE
INTO THE GREAT LAKES REGION THROUGH FRIDAY. MEANWHILE THE WEAK UPPER
LEVEL TROUGH WILL SHEAR OUT AS IT MOVES ACROSS THE REGION THROUGH
FRIDAY. LIGHT NORTHERLY WINDS THURSDAY NIGHT WILL SHIFT BACK TO THE
WEST WHICH WILL LIFT LIGHT LAKE EFFECT SNOWS BACK TO THE EASTERN
LAKE ONTARIO REGION. THE WEAK FLOW...LAKE ICE...AND LIMITED MOISTURE
SHOULD KEEP ANY ACCUMULATIONS ON THE LIGHT SIDE.
THE TEMPERATURE FORECAST WILL BE TRICKY DURING THE
PERIOD...ESPECIALLY NIGHTTIME LOWS. WINDS WILL BE FAIRLY LIGHT
THROUGHOUT THE PERIOD...BUT CLOUD COVER WILL VARY BASED ON SYNOPTIC
AND MESOSCALE FEATURES. WITH LIGHT WINDS OVERNIGHT LOWS WILL BE
CONSIDERABLY COLDER IN AREAS WHICH DO CLEAR OUT. THIS UNCERTAINTY
ASIDE...THERE IS NO QUESTION THAT IT WILL BE COLD....WITH DAYTIME
HIGHS 10 TO 15 DEGREES ON THURSDAY AND FRIDAY. OVERNIGHT LOWS WILL
LARGELY BE BELOW ZERO...BUT TEMPERATURES COULD DROP INTO THE MINUS
TEENS OR COLDER IN INTERIOR SECTIONS. THE BEST CHANCE FOR THE
COLDEST TEMPERATURES IS IN THE NORTH COUNTRY WHERE SKIES ARE MOST
LIKELY TO CLEAR.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
HIGH PRESSURE WILL GRADUALLY MOVE ACROSS THE REGION FRIDAY NIGHT
THROUGH SATURDAY NIGHT. THIS WILL BRING GENERALLY FAIR WEATHER
OUTSIDE OF SOME LIGHT LAKE EFFECT SNOW EAST OF LAKE ONTARIO WHICH
WILL WEAKEN AND LIFT NORTH WITH TIME. LOWS ON FRIDAY NIGHT SHOULD
ONCE AGAIN DROP BELOW ZERO IN MANY AREAS...WITH THE COLDEST
TEMPERATURES PROBABLY IN THE VALLEYS OF THE SOUTHERN TIER WHICH WILL
BE CLOSE TO THE CENTER OF THE HIGH. TEMPERATURES WILL REMAIN ON THE
COOL SIDE WITH HIGHS SATURDAY IN THE UPPER TEENS TO AROUND 20.
THE PATTERN BECOMES MORE COMPLEX ON SUNDAY WITH A SPLIT FLOW WHERE
THE SOUTHERN BRANCH EXTENDS FROM THE SOUTHWESTERN STATES TO THE
GREAT LAKES REGION. THIS PATTERN TENDS TO BE ACTIVE ONE FOR OUR
REGION...BUT IT IS DIFFICULT FOR GUIDANCE TO FORECAST PHASING
BETWEEN THE TWO BRANCHES. THIS PATTERN SHOULD ALSO BRING
TEMPERATURES A BIT CLOSER TO NORMAL EARLY NEXT WEEK...EVEN IF THEY
WILL STILL BE BELOW NORMAL.
12Z GUIDANCE HAS TRENDED WEAKER WITH AN INITIAL WAVE (SUNDAY NIGHT)
AND INSTEAD KEYS ON A STRONGER SYSTEM LATE TUESDAY. THERE IS STILL
PLENTY OF TIME FOR FUTURE MODEL SHIFTS...BUT THIS TREND SEEMS
REASONABLE SINCE IT TRACKS THE SUNDAY SYSTEM FURTHER SOUTH AND
YIELDS A COLDER SOLUTION. GUIDANCE NOW SUGGESTS AN ALL SNOW...BUT
LIGHTER EVENT...ON SUNDAY NIGHT. ITS WORTH NOTING THE GGEM HAS
SHIFTED SO FAR SOUTH THAT IT MISSES...BUT WITH THE 12Z GFS/ECMWF
STILL BRINGING SOME SNOW WILL KEEP LIKELY POPS.
EXPECT A BRIEF BREAK BETWEEN SYSTEMS LATE MONDAY AND INTO
TUESDAY...BUT GFS/ECMWF GUIDANCE HAS BEEN IN FAIRLY GOOD AGREEMENT
BRINGING ANOTHER MORE SIGNIFICANT WAVE TOWARD OUR REGION LATE
TUESDAY. MORE LIKELY THAN NOT...IT WILL BE COLD ENOUGH FOR SNOW WITH
THIS SYSTEM...BUT IT IS STILL A BIT TOO FAR OUT FOR SPECIFICS.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
REGIONAL RADAR SHOWING A REASONABLY WELL-DEFINED BAND OF LIGHT SNOW
THAT HAS BEEN CROSSING SRN ONTARIO THIS EVENING IS NOW CROSSING THE
NIAGARA PENINSULA AND SHOULD BE AFFECTING KIAG/KBUF WITHIN THE NEXT
HOUR. THOUGH SNOWFALL RATES ARE LIKELY MODEST..UPSTREAM OBS INDICATE
VSBYS HAVE BEEN DROPPING INTO IFR RANGE AND EXPECT THIS TREND TO
CONTINUE AS THE BAND OF SNOW MOVES INTO WRN NY. THE UPPER LEVEL
DISTURBANCE DRIVING THIS BAND WILL PUSH EAST ACROSS THE FORECAST
AREA TONIGHT...TAKING THE BAND AND ASSOCIATED IFR CONDITIONS WITH
IT. INITIAL ROUND OF IFR ASSOCIATED WITH THE BAND SHOULD LAST 2-4
HOURS WITH IMPROVEMENT TO VFR AFTER THE BAND MOVES THROUGH. THIS
IMPROVEMENT IS EXPECTED TO BE RELATIVELY BRIEF AS ANOTHER
DISTURBANCE DROPS ACROSS THE AREA LATER TONIGHT...RESULTING IN
ANOTHER ROUND OF -SHSN WITH MVFR CONDITIONS...POTENTIALLY DROPPING
TO IFR ACROSS UPSLOPE AREAS OF HIGHER TERRAIN. CONDITIONS SHOULD
THEN IMPROVE TO VFR AFTER 12Z WED AS DRIER AIR AND ARCTIC HIGH
PRESSURE INTRUDE FROM THE WEST.
OUTLOOK...
WEDNESDAY NIGHT...VFR.
THURSDAY...MVFR IN CHANCE OF SNOW SHOWERS.
FRIDAY AND SATURDAY...MAINLY VFR WITH IFR IN LAKE EFFECT SNOW.
SUNDAY...MVFR WITH SNOW SHOWERS LIKELY.
MONDAY...MVFR WITH A CHANCE OF SNOW SHOWERS...THEN IMPROVING TO VFR.
&&
.MARINE...
SOUTHWESTERLY WINDS WITH GUSTS PUSHING TO 30 KNOTS AHEAD OF A COLD
FRONT THIS EVENING. WINDS WILL THEN TURN WESTERLY TO NORTHWESTERLY
WEDNESDAY INTO WEDNESDAY NIGHT WITH THE PASSAGE OF THE ARCTIC
FRONT. SMALL CRAFT ADVISORIES FOR OPEN WATER PORTIONS OF LAKE
ONTARIO THROUGH LATE WEDNESDAY EVENING.
&&
.CLIMATE...
---THIS FEBRUARY IS WRAPPING UP TO BE ONE OF THE COLDEST AND
SNOWIEST MONTHS IN OUR PRIMARY CLIMATE STATIONS HISTORY. THE
CONTINUED NORTHWEST FLOW OF BITTERLY COLD AIR HAS LEFT THE MONTH
OF FEBRUARY A HISTORIC MONTH THAT WILL BE A BENCHMARK MARK FOR
YEARS TO COME. BELOW ARE THE COLDEST MONTHS IN EACH STATIONS
HISTORY. TEMPERATURE RECORDS FOR BUFFALO AND ROCHESTER GO BACK TO
1871...WHILE TEMPERATURE RECORDS IN WATERTOWN GO BACK TO 1950.
STATION: VALUE (F) MONTH (YEAR)
BUFFALO 11.6 FEB (1934)
13.4 FEB (1875)
13.8 JAN (1977)
14.1 JAN (1918)
14.6 FEB (1885)
14.9 FEB (1979)
15.5 FEB (1978)
15.6 JAN (1920)
15.6 JAN (1912)
16.2 JAN (1945)
ROCHESTER 12.6 FEB (1934)
13.7 FEB (1979)
14.4 FEB (1875)
14.5 FEB (1885)
14.8 JAN (1918)
14.9 JAN (1994)
15.2 JAN (1945)
15.5 JAN (1977)
15.7 JAN (1981)
16.1 JAN (1920)
WATERTOWN 6.4 DEC (1989)
6.5 JAN (1970)
6.9 JAN (1994)
7.9 FEB (1978)
8.0 JAN (1981)
8.1 JAN (2004)
8.4 FEB (1979)
10.0 JAN (2003)
10.1 JAN (1977)
10.3 JAN (1961)
CURRENT MONTHLY AVERAGE TEMPERATURES ARE LISTED ON THE CF6 CLIMATE
PRODUCT.
---FEBRUARY HAS ALSO BEEN A SNOWY MONTH AS A PERSISTENT TRACK OF
CLIPPERS WITHIN A NORTHWEST FLOW HAS MAINTAINED NICKEL AND DIME
SNOWS THROUGH THE MONTH...THIS AFTER A SIGNIFICANT SYNOPTIC STORM TO
START FEBRUARY. BELOW ARE THE TOP SNOWIEST FEBRUARY`S ON RECORD.
SNOWFALL RECORDS GO BACK TO 1884.
STATION: SNOW (IN) YEAR
BUFFALO 1 54.2 1958
2 49.5 1960
3 44.3 2015 (DATA THROUGH 2/21)
ROCHESTER 1 64.8 1958
2 58.3 1960
3 46.5 2007
4 42.7 1910
5 41.7 2015 (DATA THROUGH 2/21)
---IT IS POSSIBLE THAT BUFFALO REMAINS BELOW FREEZING THE ENTIRE
MONTH OF FEBRUARY. THIS HAS HAPPENED ONCE BEFORE...IN THE YEAR 1978.
---ROCHESTER HAS HAD 7 DAYS THIS MONTH WITH MINIMUM TEMPERATURES
FALLING BELOW ZERO. BELOW IS A LIST OF GREATEST NUMBER OF DAYS
IN FEBRUARY WITH MINIMUM TEMPERATURES BELOW ZERO...
NUMBER YEAR
10 1979
8 1934
7 1963
7 1875
7 2015 (DATA THROUGH 2/21)
THE GREATEST NUMBER OF DAYS IN A WINTER SEASON IN ROCHESTER THAT
HAVE MINIMUM TEMPERATURES FALL BELOW ZERO IS 15 DAYS SET BACK IN
1884-85.
---WATERTOWN HAS HAD 14 DAYS THIS MONTH WITH MINIMUM TEMPERATURES
FALLING BELOW ZERO. BELOW IS A LIST OF GREATEST NUMBER OF DAYS IN
FEBRUARY WITH MINIMUM TEMPERATURES BELOW ZERO...
NUMBER YEAR
16 1978
15 1993
15 1979
14 2015 (DATA THROUGH 2/21)
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW ADVISORY FROM 7 AM WEDNESDAY TO MIDNIGHT EST
WEDNESDAY NIGHT FOR NYZ006-008.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST WEDNESDAY NIGHT FOR
LOZ042-043.
SMALL CRAFT ADVISORY UNTIL 10 PM EST WEDNESDAY FOR LOZ044.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...APFFEL
LONG TERM...APFFEL
AVIATION...WOOD
MARINE...SMITH
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
935 PM EST TUE FEB 24 2015
.SYNOPSIS...
LOW PRESSURE WILL PULL AWAY FROM THE CAROLINAS TONIGHT AS WEAK
HIGH PRESSURE BUILDS OVERHEAD. A STRONG STORM SYSTEM WILL BRING
RAIN AND POSSIBLY SNOW WELL INLAND LATE WEDNESDAY INTO THURSDAY
MORNING. A MINOR WARMING TREND WILL BEGIN OVER THE WEEKEND.
MOISTURE WILL RETURN EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 930 PM TUESDAY...PRECIP IS COMPLETELY OFFSHORE AND CLOUDY
SKIES ARE ANTICIPATED TO CONTINUE OVERNIGHT. LATEST HIGH-RES
MODELS SHOW WITH THE LACK OF ADVECTION ACROSS SOUTH CAROLINA
TEMPERATURES MAY NOT FALL MUCH (IF ANY) OVERNIGHT. IN FACT WITH
TEMPERATURES NOW ABOVE FREEZING AT BOTH MYRTLE BEACH AND KINGSTREE
I AM NOT CERTAIN THERE`S MUCH CONCERN FOR ICE ON ROADS ACROSS SOME
PARTS OF NE SOUTH CAROLINA. I HAVE RE-WRITTEN THE SPECIAL WEATHER
STATEMENT TO FOCUS CONCERN ON SE NORTH CAROLINA WHERE WE ARE
SEEING REPORTS OF MULTIPLE CLOSED BRIDGES AND ELEVATED ROADS IN
WILMINGTON.
DISCUSSION FROM 645 PM FOLLOWS...
ITS BEEN A HECTIC FEW HOURS HERE. A BAND OF MODERATE FREEZING RAIN
THAT EXTENDED AS FAR WEST AS THE SC MIDLANDS EARLIER THIS
AFTERNOON IS FINALLY PUSHING OFF THE COAST NEAR CAPE FEAR THIS
EVENING. THIS PRECIPITATION FELL PRIMARILY ACROSS SE NORTH
CAROLINA WHERE AIR TEMPERATURES WERE IN THE 28-31
RANGE...PRODUCING LARGE AMOUNTS OF FREEZING RAIN BETWEEN 2-6 PM.
THE FREEZING RAIN SENSOR AT THE ILM (WILMINGTON) ASOS REPORTED
0.40 INCHES OF ICE ACCRETION TODAY. NORMALLY OUTPUT FROM THIS
SENSOR AGREES QUITE WELL WITH HUMAN-OBSERVED ACCRETION ON ELEVATED
OBJECTS AT THE NWS OFFICE...BUT THE ASOS SENSOR APPEARS TO HAVE
RUN A LITTLE HIGH WITH ITS TOTALS TODAY AS WE ARE ESTIMATING
CLOSER TO 0.25 INCHES OF ICE ACCRETION HERE. REPORTS RECEIVED VIA
FACEBOOK AND TWITTER CONFIRM WIDESPREAD 0.25 INCH ICE
ACCUMULATIONS AROUND THE CAPE FEAR AREA TODAY...VERIFYING THE ICE
STORM WARNING THAT WAS ISSUED EARLIER.
RADAR ECHOES ARE PUSHING OFFSHORE AT 40 KNOTS...HOWEVER ASOS/AWOS
OBSERVATIONS AND A PHONE CALL FROM THE NCDOT IN LUMBERTON EARLIER
CONFIRMS THAT A COUPLE HOURS OF FREEZING DRIZZLE CONTINUES BEHIND
THE RADAR-OBSERVED BACK EDGE OF THE PRECIP SHIELD. FOR THIS REASON
I WILL MAINTAIN THE WATCHES AND ADVISORIES UNTIL 8 PM EAST OF
I-95.
FOR THE REMAINDER OF THE OVERNIGHT PERIOD...IT APPEARS LOW CLOUDS
WILL HOLD TOUGH FOR ALL BUT PERHAPS THE LUMBERTON-BENNETTSVILLE
AREA WHERE SOME LIMITED CLEARING MAY DEVELOP LATE TONIGHT AS
MOISTURE THINS FROM ALOFT. THIS WILL PREVENT ANY SIGNIFICANT
RADIATIONAL COOLING AND LOWS SHOULD RANGE FROM 26-30...COOLEST
NEAR LUMBERTON AND WARMEST NEAR GEORGETOWN. THE 12Z & 18Z GFS
BOTH APPEAR TO BE UP THE SAME ANTICS PULLED DURING LAST WEEK`S
ARCTIC COLD WHERE IT SEVERELY OVERESTIMATES RADIATIONAL COOLING
POTENTIAL OVER MEAGER SNOWPACK ACROSS MUCH OF NORTH CAROLINA. THE
18Z NAM AND 22Z RUC LOOK MUCH MORE REASONABLE FOR TEMPERATURES
OVERNIGHT.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...MAIN FORECAST EMPHASIS IS THE STORM SYSTEM
CURRENTLY TAKING SHAPE IN THE NEW MEXICO REGION. THIS SYSTEM WILL
RACE ACROSS THE SOUTHERN STATES OVER THE NEXT 24-48 HOURS IN WHAT
IS BASICALLY A WESTERLY FLOW ALOFT. LOW PRESSURE WILL DEVELOP IN
THE GULF OF MEXICO AND MOVE OFFSHORE...EAST OF CHARLESTON BY 0600
UTC THURSDAY. BY 1200 UTC THURSDAY THE LOW WILL BE WELL EAST OF
THE OUTER BANKS.
FORCING WITH THE SYSTEM WILL COME IN A COUPLED FASHION WITH LOWER
LEVEL ISENTROPIC LIFT ON THE 290K SURFACE AND MID LEVEL
FRONTOGENESIS. THE DOMINANT COMPONENT IS BY FAR THE ISENTROPIC LIFT
AND THIS OF COURSE LEADS TO PRECIPITATION TYPE ISSUES ACROSS MOST OF
THE AREA.
FOR THE MOST PART...THERMAL PROFILES SUPPORT RAIN INITIALLY. AS
DYNAMIC COOLING TAKES PLACE ALONG WITH HEAVIER QPF RATES SOUNDINGS
COOL IN THE NORTHERN MOST COUNTIES TO MARGINALLY SUPPORT SNOW. THE
MODELS IF ANYTHING HAVE TRENDED JUST A LITTLE WARMER HOWEVER AND
CONFIDENCE IS NOT OVERWHELMING. THAT BEING SAID IF THE DYNAMIC LIFT
IS A LITTLE STRONGER THAN PERFECT PROGS...A COOLING OF THE PROFILE
COULD OCCUR WHICH WOULD LEAD TO MORE SUPPORT FOR SNOW. FOR NOW...I
HAVE A RAIN AND SNOW MIX FOR MARLBORO...ROBESON AND BLADEN COUNTIES
AND TOTAL ACCUMULATIONS OF JUST OVER TWO INCHES. THIS WARRANTS A
WINTER STORM WATCH FOR THESE AREAS WHICH WILL BE RAISED THIS
AFTERNOON. IT COULD BE A SITUATION WHERE SNOW IS THE PREDOMINANT
TYPE WITH RAIN MIXING FROM TIME TO TIME...AT LEAST A COUPLE OF HOURS
EITHER SIDE OF 0600 UTC. OVERALL I CANT RULE OUT A COUPLE OF INCHES
OF VERY WET/HEAVY SNOW IN THESE AREAS. IF SNOW DOES INDEED
DEVELOP...IT WONT TAKE LONG TO ACCUMULATE AS THE RATES SHOULD BE
VERY HIGH...AGAIN AT LEAST FOR A COUPLE OF HOURS EITHER SIDE OF 0600
UTC.
AS THE SYSTEM MOVES OUT BEYOND 0600 UTC PROFILES BRIEFLY SUPPORT
SOME SNOW IN OTHER AREAS AND I HAVE AMOUNTS RANGING FROM 0.7 INCHES
FROM NORTHWEST TO JUST OVER ONE HALF OF IN INCH CLOSER TO THE COAST.
THIS CAN PROBABLY BE ADDRESSED WITH A WINTER WEATHER
ADVISORY...ALTHOUGH TECHNICALLY JUST UNDER CRITERIA BUT WITH A
WINTER STORM WATCH FLOATING AROUND...IT MAY BE PRUDENT TO ISSUE AN
ADVISORY FOR PUBLIC IMPACT...AFTER THE CURRENT ONE HAS EXPIRED.
THE REMAINDER OF THURSDAY WILL FEATURE OVERCAST SKIES WITH PATCHY
DRIZZLE. HIGH TEMPERATURES WILL STRUGGLE TO REACH 40. YET ANOTHER
COLD AND BLUSTERY OVERNIGHT PERIOD FOR THURSDAY INTO FRIDAY MORNING
WITH LOWS IN THE MIDDLE 20S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 PM TUESDAY...BROAD LOW AMPLITUDE MID LEVEL FLOW ACROSS MOST
OF THE CONUS ON FRIDAY WITH LARGE HIGH PRESSURE AT THE SURFACE
CENTERED OVER EASTERN U.S. THIS WILL BRING A NORTHERLY FLOW LOCALLY
THAT WILL KEEP TEMPERATURES BELOW CLIMO AND LIKELY QUITE A FEW
CLOUDS TRAPPED UNDER AN INVERSION. NOT MUCH CHANGES HEADING INTO
SATURDAY AND SO THE FORECAST IS QUITE SIMILAR. ON SUNDAY THE CENTER
OF THE SURFACE HIGH SLIDES EAST AND EXTENDS A WEDGE AXIS INTO THE
CAROLINAS WHILE OFFSHORE TROUGHINESS DEVELOPS. MODELS LOOKING WETTER
AS THIS OCCURS AS WARM ADVECTION RIDES ATOP THIS SURFACE-BASED
AIRMASS LEADS TO GOOD ISENTROPIC UPGLIDE. GUIDANCE ALSO SUGGESTING A
MILDER AFTERNOON BUT THIS MAY NEED TO BE REVISITED ESPECIALLY IF
RAIN DOES MATERIALIZE. THE WEDGE BREAKS DOWN RAPIDLY BY MONDAY
ALLOWING FOR MODERATION IN TEMPERATURES AND PERHAPS SOME
UNSEASONABLY MILD NIGHTS BUT THE MOISTURE WILL REMAIN AND SOME
LIGHT RAIN CHANCES ARE STILL WARRANTED IF NOTHING ELSE DUE TO THE
APPROACH OF A WEAK COLD FRONT. THIS BOUNDARY APPEARS TO STALL ACROSS
THE AREA ON TUESDAY KEEPING CLOUDS AND RAIN IN THE FORECAST.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
AS OF 00Z...MVFR TO IFR CONDITIONS WILL CONTINUE THROUGH THE
OVERNIGHT PERIOD ACROSS THE TERMINALS ALONG WITH SOME ISOLATED
POCKETS OF FREEZING DRIZZLE FOR THE COASTAL TERMINALS. PRECIPITATION
IS SLOWLY MAKING AN EASTWARD PROGRESS AS MAIN LOW PRESSURE SYSTEM
EXITS THE SE COASTS. WINDS WILL BECOME LIGHT AND WITH THE MOISTURE
FROM TODAYS PRECIPITATION EXPECT BR AND FG ACROSS ALL TERMINALS WITH
IFR/LIFR CONDITIONS UNTIL MORNING. ANOTHER LOW PRESSURE SYSTEM WILL
APPROACH THE REGION ON WEDNESDAY. PRECIPITATION CHANCES START TO
INCREASE ACROSS THE INLAND TERMINALS AFTER 20Z AND WILL INCLUDE A
TEMPO GROUP AT FLO/LBT TO ACCOUNT FOR THIS. THERE IS A CHANCE OF
PRECIPITATION REACHING THE COASTAL TERMINALS AS WELL BUT I WILL NOT
MENTION IN TERMINALS AT THIS TIME AS BETTER CHANCES EXIST AFTER 00Z
AND TAF PERIOD.
EXTENDED OUTLOOK...LOW PRESSURE WILL MOVE ACROSS THE TERMINALS WED
AFTERNOON INTO THURS WITH VARIABLE FLIGHT CONDITIONS...RAIN AND
WINTRY PRECIPITATION MAINLY AT KFLO/KLBT/KILM. BECOMING VFR FRI
EXTENDING INTO SAT. MVFR/IFR/RAIN SUNDAY.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST THIS EVENING AS WINDS AND SEAS ARE BEHAVING NICELY.
DISCUSSION FROM 645 PM FOLLOWS...
LOW PRESSURE WELL EAST OF THE SOUTH CAROLINA COAST WILL CONTINUE
TO PUSH NORTHEAST AND AWAY FROM THE AREA OVERNIGHT. THIS WILL
ALLOW WEAK HIGH PRESSURE INLAND TO SPREAD DOWN TO THE COAST
OVERNIGHT...WITH VEERING WINDS AND WEAKENING WIND SPEEDS. THE
SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT FOR THE NC WATERS WHERE
THE FRYING PAN SHOALS BUOY IS STILL REPORTING 7.5 FOOT SEAS. WEST
OF FRYING PAN SHOALS CONDITIONS APPEAR TO BE IMPROVING A LITTLE
FASTER.
NOTE THAT SOME WIND SENSORS NEAR THE COAST APPEAR TO HAVE FROZEN
ANEMOMETER CUPS AND ARE NOT TO BE TRUSTED.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...COASTAL WATERS WILL SEE A BRIEF RESPITE FROM
RUGGED CONDITIONS EARLY WEDNESDAY AS WINDS WILL BE RELATIVELY LIGHT
FROM THE NORTHWEST...TEN KNOTS OR LESS AS LOW PRESSURE DEVELOPS AND
MOVES WELL OFFSHORE...WINDS WILL TURN TO THE NORTHEAST AND INCREASE
IN MAGNITUDE TO 20-25 KNOTS BY EARLY THURSDAY MORNING. WINDS TURN TO
A MORE NORTHERLY DIRECTION DURING THE DAY THURSDAY AND SEEM
CONSISTENT IN A 10-15 KNOT RANGE...MOSTLY LEANING TOWARD THE HIGHER
SIDE. SIGNIFICANT SEAS START OUT SLOW AS WELL 1-2 FEET THEN RAMP UP
WELL INTO SMALL CRAFT CRITERIA BY LATE THURSDAY EVENING. BY LATE
THURSDAY HEIGHTS DROP BACK A BIT PROBABLY BELOW SMALL CRAFT
CRITERIA.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 300 PM TUESDAY...A LARGE AREA OF HIGH PRESSURE COVERING THE
EASTERN U.S. TO BRING A NORTHERLY WIND LOCALLY THAT WILL BE MODERATE
BUT NO FLAGS EXPECTED AT THIS TIME. THE CENTER OF THIS HIGH WILL
SHIFT EAST A BIT ON SATURDAY BUT THE LOCAL EFFECTS WILL BE THOSE OF
MINIMAL CHANGE. THE INCREASED DURATION OF THE LARGELY
COAST-PARALLEL NE WINDS COULD ALLOW FOR AN UPTICK IN OFFSHORE SEAS
BUT FOR NOW IT STILL SEEMS NO ADVISORIES WILL COME TO PASS. 5 FT
SEAS WILL BE QUITE PREVALENT ACROSS MOST ZONES AWAY FROM SHORE BUT
THE NEARSHORE WAVE SHADOWING MAY PRECLUDE EVEN CAUTIONARY HEADLINES.
THE HIGH SHIFTS FURTHER EAST ON SUNDAY AND EXTENDS A RIDGE AXIS ITO
THE CAROLINAS WHILE TROUGHINESS DEVELOPS JUST EAST OF THE FORECAST
WATERS. THIS HAS CAST SOME UNCERTAINTY ON THE FORECAST AS WIND SPEED
AND EVEN DIRECTION COULD VARY CONSIDERABLY DEPENDING ON WHERE THE
TROUGH-BORN WIND SHIFT DECIDES TO SET UP. CURRENTLY IT SEEMS TO BE
JUST FAR ENOUGH OFFSHORE THAT LOCAL WINDS STAY NORTHEASTERLY AND
GROW A BIT LIGHTER.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY
MORNING FOR SCZ017.
NC...WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY
MORNING FOR NCZ087-096.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR AMZ250-252.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...MAC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
645 PM EST TUE FEB 24 2015
.SYNOPSIS...
LOW PRESSURE WILL PULL AWAY FROM THE CAROLINAS TONIGHT AS WEAK
HIGH PRESSURE BUILDS OVERHEAD. A STRONG STORM SYSTEM WILL BRING
RAIN AND POSSIBLY SNOW WELL INLAND LATE WEDNESDAY INTO THURSDAY
MORNING. A MINOR WARMING TREND WILL BEGIN OVER THE WEEKEND.
MOISTURE WILL RETURN EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 645 PM TUESDAY...ITS BEEN A HECTIC FEW HOURS HERE. A BAND OF
MODERATE FREEZING RAIN THAT EXTENDED AS FAR WEST AS THE SC
MIDLANDS EARLIER THIS AFTERNOON IS FINALLY PUSHING OFF THE COAST
NEAR CAPE FEAR THIS EVENING. THIS PRECIPITATION FELL PRIMARILY
ACROSS SE NORTH CAROLINA WHERE AIR TEMPERATURES WERE IN THE 28-31
RANGE...PRODUCING LARGE AMOUNTS OF FREEZING RAIN BETWEEN 2-6 PM.
THE FREEZING RAIN SENSOR AT THE ILM (WILMINGTON) ASOS REPORTED
0.40 INCHES OF ICE ACCRETION TODAY. NORMALLY OUTPUT FROM THIS
SENSOR AGREES QUITE WELL WITH HUMAN-OBSERVED ACCRETION ON
ELEVATED OBJECTS AT THE NWS OFFICE...BUT THE ASOS SENSOR APPEARS
TO HAVE RUN A LITTLE HIGH WITH ITS TOTALS TODAY AS WE ARE
ESTIMATING CLOSER TO 0.25 INCHES OF ICE ACCRETION HERE. REPORTS
RECEIVED VIA FACEBOOK AND TWITTER CONFIRM WIDESPREAD 0.25 INCH ICE
ACCUMULATIONS AROUND THE CAPE FEAR AREA TODAY...VERIFYING THE ICE
STORM WARNING THAT WAS ISSUED EARLIER.
RADAR ECHOES ARE PUSHING OFFSHORE AT 40 KNOTS...HOWEVER ASOS/AWOS
OBSERVATIONS AND A PHONE CALL FROM THE NCDOT IN LUMBERTON EARLIER
CONFIRMS THAT A COUPLE HOURS OF FREEZING DRIZZLE CONTINUES BEHIND
THE RADAR-OBSERVED BACK EDGE OF THE PRECIP SHIELD. FOR THIS REASON
I WILL MAINTAIN THE WATCHES AND ADVISORIES UNTIL 8 PM EAST OF
I-95.
FOR THE REMAINDER OF THE OVERNIGHT PERIOD...IT APPEARS LOW CLOUDS
WILL HOLD TOUGH FOR ALL BUT PERHAPS THE LUMBERTON-BENNETTSVILLE
AREA WHERE SOME LIMITED CLEARING MAY DEVELOP LATE TONIGHT AS
MOISTURE THINS FROM ALOFT. THIS WILL PREVENT ANY SIGNIFICANT
RADIATIONAL COOLING AND LOWS SHOULD RANGE FROM 26-30...COOLEST
NEAR LUMBERTON AND WARMEST NEAR GEORGETOWN. THE 12Z & 18Z GFS
BOTH APPEAR TO BE UP THE SAME ANTICS PULLED DURING LAST WEEK`S
ARCTIC COLD WHERE IT SEVERELY OVERESTIMATES RADIATIONAL COOLING
POTENTIAL OVER MEAGER SNOWPACK ACROSS MUCH OF NORTH CAROLINA. THE
18Z NAM AND 22Z RUC LOOK MUCH MORE REASONABLE FOR TEMPERATURES
OVERNIGHT.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...MAIN FORECAST EMPHASIS IS THE STORM SYSTEM
CURRENTLY TAKING SHAPE IN THE NEW MEXICO REGION. THIS SYSTEM WILL
RACE ACROSS THE SOUTHERN STATES OVER THE NEXT 24-48 HOURS IN WHAT
IS BASICALLY A WESTERLY FLOW ALOFT. LOW PRESSURE WILL DEVELOP IN
THE GULF OF MEXICO AND MOVE OFFSHORE...EAST OF CHARLESTON BY 0600
UTC THURSDAY. BY 1200 UTC THURSDAY THE LOW WILL BE WELL EAST OF
THE OUTER BANKS.
FORCING WITH THE SYSTEM WILL COME IN A COUPLED FASHION WITH LOWER
LEVEL ISENTROPIC LIFT ON THE 290K SURFACE AND MID LEVEL
FRONTOGENESIS. THE DOMINANT COMPONENT IS BY FAR THE ISENTROPIC LIFT
AND THIS OF COURSE LEADS TO PRECIPITATION TYPE ISSUES ACROSS MOST OF
THE AREA.
FOR THE MOST PART...THERMAL PROFILES SUPPORT RAIN INITIALLY. AS
DYNAMIC COOLING TAKES PLACE ALONG WITH HEAVIER QPF RATES SOUNDINGS
COOL IN THE NORTHERN MOST COUNTIES TO MARGINALLY SUPPORT SNOW. THE
MODELS IF ANYTHING HAVE TRENDED JUST A LITTLE WARMER HOWEVER AND
CONFIDENCE IS NOT OVERWHELMING. THAT BEING SAID IF THE DYNAMIC LIFT
IS A LITTLE STRONGER THAN PERFECT PROGS...A COOLING OF THE PROFILE
COULD OCCUR WHICH WOULD LEAD TO MORE SUPPORT FOR SNOW. FOR NOW...I
HAVE A RAIN AND SNOW MIX FOR MARLBORO...ROBESON AND BLADEN COUNTIES
AND TOTAL ACCUMULATIONS OF JUST OVER TWO INCHES. THIS WARRANTS A
WINTER STORM WATCH FOR THESE AREAS WHICH WILL BE RAISED THIS
AFTERNOON. IT COULD BE A SITUATION WHERE SNOW IS THE PREDOMINANT
TYPE WITH RAIN MIXING FROM TIME TO TIME...AT LEAST A COUPLE OF HOURS
EITHER SIDE OF 0600 UTC. OVERALL I CANT RULE OUT A COUPLE OF INCHES
OF VERY WET/HEAVY SNOW IN THESE AREAS. IF SNOW DOES INDEED
DEVELOP...IT WONT TAKE LONG TO ACCUMULATE AS THE RATES SHOULD BE
VERY HIGH...AGAIN AT LEAST FOR A COUPLE OF HOURS EITHER SIDE OF 0600
UTC.
AS THE SYSTEM MOVES OUT BEYOND 0600 UTC PROFILES BRIEFLY SUPPORT
SOME SNOW IN OTHER AREAS AND I HAVE AMOUNTS RANGING FROM 0.7 INCHES
FROM NORTHWEST TO JUST OVER ONE HALF OF IN INCH CLOSER TO THE COAST.
THIS CAN PROBABLY BE ADDRESSED WITH A WINTER WEATHER
ADVISORY...ALTHOUGH TECHNICALLY JUST UNDER CRITERIA BUT WITH A
WINTER STORM WATCH FLOATING AROUND...IT MAY BE PRUDENT TO ISSUE AN
ADVISORY FOR PUBLIC IMPACT...AFTER THE CURRENT ONE HAS EXPIRED.
THE REMAINDER OF THURSDAY WILL FEATURE OVERCAST SKIES WITH PATCHY
DRIZZLE. HIGH TEMPERATURES WILL STRUGGLE TO REACH 40. YET ANOTHER
COLD AND BLUSTERY OVERNIGHT PERIOD FOR THURSDAY INTO FRIDAY MORNING
WITH LOWS IN THE MIDDLE 20S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 PM TUESDAY...BROAD LOW AMPLITUDE MID LEVEL FLOW ACROSS MOST
OF THE CONUS ON FRIDAY WITH LARGE HIGH PRESSURE AT THE SURFACE
CENTERED OVER EASTERN U.S. THIS WILL BRING A NORTHERLY FLOW LOCALLY
THAT WILL KEEP TEMPERATURES BELOW CLIMO AND LIKELY QUITE A FEW
CLOUDS TRAPPED UNDER AN INVERSION. NOT MUCH CHANGES HEADING INTO
SATURDAY AND SO THE FORECAST IS QUITE SIMILAR. ON SUNDAY THE CENTER
OF THE SURFACE HIGH SLIDES EAST AND EXTENDS A WEDGE AXIS INTO THE
CAROLINAS WHILE OFFSHORE TROUGHINESS DEVELOPS. MODELS LOOKING WETTER
AS THIS OCCURS AS WARM ADVECTION RIDES ATOP THIS SURFACE-BASED
AIRMASS LEADS TO GOOD ISENTROPIC UPGLIDE. GUIDANCE ALSO SUGGESTING A
MILDER AFTERNOON BUT THIS MAY NEED TO BE REVISITED ESPECIALLY IF
RAIN DOES MATERIALIZE. THE WEDGE BREAKS DOWN RAPIDLY BY MONDAY
ALLOWING FOR MODERATION IN TEMPERATURES AND PERHAPS SOME
UNSEASONABLY MILD NIGHTS BUT THE MOISTURE WILL REMAIN AND SOME
LIGHT RAIN CHANCES ARE STILL WARRANTED IF NOTHING ELSE DUE TO THE
APPROACH OF A WEAK COLD FRONT. THIS BOUNDARY APPEARS TO STALL ACROSS
THE AREA ON TUESDAY KEEPING CLOUDS AND RAIN IN THE FORECAST.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 00Z...MVFR TO IFR CONDITIONS WILL CONTINUE THROUGH THE
OVERNIGHT PERIOD ACROSS THE TERMINALS ALONG WITH SOME ISOLATED
POCKETS OF FREEZING DRIZZLE FOR THE COASTAL TERMINALS. PRECIPITATION
IS SLOWLY MAKING AN EASTWARD PROGRESS AS MAIN LOW PRESSURE SYSTEM
EXITS THE SE COASTS. WINDS WILL BECOME LIGHT AND WITH THE MOISTURE
FROM TODAYS PRECIPITATION EXPECT BR AND FG ACROSS ALL TERMINALS WITH
IFR/LIFR CONDITIONS UNTIL MORNING. ANOTHER LOW PRESSURE SYSTEM WILL
APPROACH THE REGION ON WEDNESDAY. PRECIPITATION CHANCES START TO
INCREASE ACROSS THE INLAND TERMINALS AFTER 20Z AND WILL INCLUDE A
TEMPO GROUP AT FLO/LBT TO ACCOUNT FOR THIS. THERE IS A CHANCE OF
PRECIPITATION REACHING THE COASTAL TERMINALS AS WELL BUT I WILL NOT
MENTION IN TERMINALS AT THIS TIME AS BETTER CHANCES EXIST AFTER 00Z
AND TAF PERIOD.
EXTENDED OUTLOOK...LOW PRESSURE WILL MOVE ACROSS THE TERMINALS WED
AFTERNOON INTO THURS WITH VARIABLE FLIGHT CONDITIONS...RAIN AND
WINTRY PRECIPITATION MAINLY AT KFLO/KLBT/KILM. BECOMING VFR FRI
EXTENDING INTO SAT. MVFR/IFR/RAIN SUNDAY.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 PM TUESDAY...LOW PRESSURE WELL EAST OF THE SOUTH
CAROLINA COAST WILL CONTINUE TO PUSH NORTHEAST AND AWAY FROM THE
AREA OVERNIGHT. THIS WILL ALLOW WEAK HIGH PRESSURE INLAND TO
SPREAD DOWN TO THE COAST OVERNIGHT...WITH VEERING WINDS AND WEAKENING
WIND SPEEDS. THE SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT FOR
THE NC WATERS WHERE THE FRYING PAN SHOALS BUOY IS STILL REPORTING
7.5 FOOT SEAS. WEST OF FRYING PAN SHOALS CONDITIONS APPEAR TO BE
IMPROVING A LITTLE FASTER.
NOTE THAT SOME WIND SENSORS NEAR THE COAST APPEAR TO HAVE FROZEN
ANEMOMETER CUPS AND ARE NOT TO BE TRUSTED.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...COASTAL WATERS WILL SEE A BRIEF RESPITE FROM
RUGGED CONDITIONS EARLY WEDNESDAY AS WINDS WILL BE RELATIVELY LIGHT
FROM THE NORTHWEST...TEN KNOTS OR LESS AS LOW PRESSURE DEVELOPS AND
MOVES WELL OFFSHORE...WINDS WILL TURN TO THE NORTHEAST AND INCREASE
IN MAGNITUDE TO 20-25 KNOTS BY EARLY THURSDAY MORNING. WINDS TURN TO
A MORE NORTHERLY DIRECTION DURING THE DAY THURSDAY AND SEEM
CONSISTENT IN A 10-15 KNOT RANGE...MOSTLY LEANING TOWARD THE HIGHER
SIDE. SIGNIFICANT SEAS START OUT SLOW AS WELL 1-2 FEET THEN RAMP UP
WELL INTO SMALL CRAFT CRITERIA BY LATE THURSDAY EVENING. BY LATE
THURSDAY HEIGHTS DROP BACK A BIT PROBABLY BELOW SMALL CRAFT
CRITERIA.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 300 PM TUESDAY...A LARGE AREA OF HIGH PRESSURE COVERING THE
EASTERN U.S. TO BRING A NORTHERLY WIND LOCALLY THAT WILL BE MODERATE
BUT NO FLAGS EXPECTED AT THIS TIME. THE CENTER OF THIS HIGH WILL
SHIFT EAST A BIT ON SATURDAY BUT THE LOCAL EFFECTS WILL BE THOSE OF
MINIMAL CHANGE. THE INCREASED DURATION OF THE LARGELY
COAST-PARALLEL NE WINDS COULD ALLOW FOR AN UPTICK IN OFFSHORE SEAS
BUT FOR NOW IT STILL SEEMS NO ADVISORIES WILL COME TO PASS. 5 FT
SEAS WILL BE QUITE PREVALENT ACROSS MOST ZONES AWAY FROM SHORE BUT
THE NEARSHORE WAVE SHADOWING MAY PRECLUDE EVEN CAUTIONARY HEADLINES.
THE HIGH SHIFTS FURTHER EAST ON SUNDAY AND EXTENDS A RIDGE AXIS ITO
THE CAROLINAS WHILE TROUGHINESS DEVELOPS JUST EAST OF THE FORECAST
WATERS. THIS HAS CAST SOME UNCERTAINTY ON THE FORECAST AS WIND SPEED
AND EVEN DIRECTION COULD VARY CONSIDERABLY DEPENDING ON WHERE THE
TROUGH-BORN WIND SHIFT DECIDES TO SET UP. CURRENTLY IT SEEMS TO BE
JUST FAR ENOUGH OFFSHORE THAT LOCAL WINDS STAY NORTHEASTERLY AND
GROW A BIT LIGHTER.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR SCZ053-
054.
WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY
MORNING FOR SCZ017.
NC...ICE STORM WARNING UNTIL 8 PM EST THIS EVENING FOR NCZ105>109.
WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR NCZ096-
099-110.
WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY
MORNING FOR NCZ087-096.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR AMZ250-252.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...MAC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
257 PM EST MON FEB 23 2015
.SYNOPSIS..A COLD FRONT WILL SETTLE SOUTHEAST OF THE AREA THIS
AFTERNOON. A WEAK WAVE OF LOW PRESSURE WILL TRACK NORTHEASTWARD
ALONG THE FRONT TONIGHT THROUGH TUESDAY... AS ARCTIC HIGH PRESSURE
BUILDS INTO THE AREA FROM THE NORTH. A SECOND STRONGER LOW PRESSURE
AREA WILL TRACK ALONG THE FRONT MIDWEEK... MOVING JUST SOUTHEAST OF
THE AREA WEDNESDAY NIGHT THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 1015 AM MONDAY...
A LOW AMPLITUDE SHORTWAVE AND ASSOCIATED WEAK SURFACE LOW ARE
DEPARTING THE SC COAST THIS MORNING. ANAFRONTAL PRECIP MAINLY
SOUTHEAST OF THE TRIANGLE AREA WILL ALSO CONTINUE TO EXIT TO THE
EAST THROUGH EARLY AFTERNOON. WEAK COLD ADVECTION WILL PERSIST THIS
AFTERNOON BEFORE THE STRONGER SURGE OCCURS THIS EVENING AHEAD THE
ARCTIC HIGH BUILDING ACROSS THE CENTRAL APPALACHIANS. DUE TO THE
DELAYED ARRIVAL OF COLDER LOW-LEVEL AIR...THE WETBULB FREEZING LINE
IS STILL WELL TO OUR NORTH IN CENTRAL VA AND BY THE TIME IT SINKS
SOUTH IN THE NORTHERN COASTAL PLAIN THIS AFTERNOON... ALL DEEPER
MOISTURE AND PRECIP WILL EITHER HAVE DEPARTED OR PRECIP WON`T BE OF
SUFFICIENT INTENSITY TO CAUSE WETBULBING OR ANY WINTRY IMPACTS.
LATEST GUIDANCE REFLECTS THIS. WILL KEEP THE GENERAL TREND OF POPS
GOING AND JUST MAKE SOME ALTERATIONS TO ACCOUNT FOR LATEST
RADAR....WITH POPS ENDING AFTER 18Z. WILL ALSO HAVE AN EYE ON THE
POTENTIAL FOR A MESOSCALE BAND OF SHALLOW MOISTURE AND PRECIP (MOST
LIKELY SLEET BASED ON TEMPS AROUND -10C IN THE SHALLOW SATURATED
LAYER) IN THE 21Z TO 03Z TIME FRAME...THOUGH NO IMPACT WOULD BE
EXPECTED AT THIS TIME. HI-RES MODELS ARE STILL SPLIT ON WHETHER OR
NOT THIS WILL DEVELOP...BUT MODELS HAVE BEEN SHOWING SOMETHING OF
THIS NATURE FOR MULTIPLE RUNS.
REGARDING TEMPS...THICKNESSES WILL STEADILY FALL THROUGHOUT THE DAY
IN THE NORTHEAST FLOW...SO FOR MANY LOCATIONS HIGHS IN THE UPPER 30S
NORTH TO MID 40S SOUTH HAVE ALREADY OCCURRED. THE HRRR SHOWS SOME
INTERMITTENT BREAKS IN CLOUDS OVER THE THE NORTHWEST PIEDMONT WITH
WESTERLY FLOW ALOFT AND NOT AS MUCH LOW-LEVEL MOISTURE THERE. NOT
CONFIDENT IN THE UPPER 40S THE HRRR GIVES...BUT THERE COULD BE A
LITTLE WARMING THROUGH EARLY AFTERNOON.
TONIGHT: THE SECOND BATCH OF S/W ENERGY MOVES INTO THE AREA BETWEEN
06 TO 12Z TUESDAY. RESULTANT WEAK DPVA AND SHALLOW ISENTROPIC
UPGLIDE WILL RE-NEW/DEEPEN SATURATION ALOFT TO SUPPORT SOME LIGHT
SNOW AND FLURRIES INTO THE AREA AROUND DAYBREAK ACROSS THE WESTERN
AND SOUTHERN PORTIONS OF THE FORECAST AREA. MODELS ARE ONLY
GENERATING A HUNDREDTH OR TWO ACROSS THE AREA SO NO ACCUMULATION ARE
EXPECTED. CAA WILL GOVERN LOWS TONIGHT...RANGING FROM UPPER TEENS
ACROSS THE NE TO MID 20S SOUTH.
TUESDAY AND TUESDAY NIGHT: TRANSITORY ARCTIC HIGH PRESSURE WILL HAVE
SETTLED ACROSS THE HEART OF CENTRAL NC BY TUESDAY MORNING. THIS HIGH
PRESSURE WILL BE NUDGED OFFSHORE BY LATE DAY AS A FAST MOVING SHORT
WAVE MOVES EAST ACROSS THE AREA. BRIEF SOUTHERLY FLOW AND WEAK
SUPPORT ALOFT WILL POTENTIALLY PRODUCE SOME LIGHT
SNOW/FLURRIES...MAINLY ACROSS THE SOUTHERN TIER AND THE WESTERN
PIEDMONT TUESDAY MORNING THROUGH AROUND MID DAY. OTHERWISE...SKIES
WILL REMAIN BE MOSTLY CLOUDY THROUGH THE DAY WITH HIGHS PEAKING IN
THE MID TO UPPER 30S. MINOR MODERATION IN MIN TEMPS IS EXPECTED TUE
NIGHT WITH DOWNSLOPE WARMING IN GENERALLY WESTERLY LOW LEVEL FLOW
AIDED BY STREAMING MID TO HIGH CLOUDINESS ALOFT IN THE FAST
CONFLUENT FLOW. MINS WILL BE MOSTLY IN THE MID 20S. -MLM
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 355 PM MONDAY...
THERE IS STILL A BIT OF UNCERTAINTY WITH THE TRACK OF A LOW THAT
DEVELOPS OVER THE GULF AND MOVES NORTHEAST ALONG THE SOUTHEAST U.S.
COAST AND THUS THE CONFIDENCE IS BELOW AVERAGE. HOWEVER...GIVEN THAT
THE TRACK OF THE LOW IS NOT LIKELY TO SHIFT SIGNIFICANTLY...IT IS
LIKELY THAT SNOW WILL OCCUR OVER A PORTION OF CENTRAL NC WEDNESDAY
NIGHT THROUGH THURSDAY MORNING...WITH HIGH CHANCES OF RAIN OR SNOW
ACROSS THE ENTIRE AREA. KEEP IN MIND THOUGH THAT CHANGES IN THE LOW
TRACK WILL RESULT IN CHANGES TO THE P-TYPE...DURATION...AND AMOUNTS.
THE LATEST GFS ANALYZES THE LOW FARTHER EAST THAN THE ECMWF...
FAVORING LOWER RAIN/SNOW AMOUNTS BUT BETTER CHANCES FOR SNOW THAN
RAIN. SHOULD THE LOW TRACK BE FARTHER EAST IT WOULD FAVOR EVEN LESS
PRECIP. HOWEVER...A TRACK CLOSER TO THE CAROLINA COAST WOULD FAVOR
MORE PRECIP BUT HIGHER CHANCES OF RAIN THAN SNOW. REGARDLESS...
CURRENT FORECASTS SUGGEST A NOT SO NICE 12-24 HOUR PERIOD AND AS OF
THE LATEST FORECAST EXPECT SNOW ACCUMULATIONS OF UP TO 2 INCHES IN
THE NORTHEAST. TEMPERATURES WEDNESDAY AFTERNOON IN THE MID TO UPPER
40S WILL DECREASE INTO THE MID 20S NORTH TO AROUND 30 DEGREES SOUTH
WITH AT LEAST SOME SNOW POSSIBLE OVER THE ENTIRE CWA. TEMPERATURES
WILL RISE INTO THE UPPER 30S TO LOW 40S ON THURSDAY...WITH ALL
LINGERING PRECIPITATION CHANGING OVER TO RAIN BEFORE ENDING THURSDAY
EVENING/NIGHT. THE LOW WILL START TO MOVE AWAY FROM THE COAST...
ALLOWING HIGH PRESSURE TO BUILD IN. DESPITE THE LINGERING CLOUDS...
THE COLD ADVECTION SHOULD BE ENOUGH TO RESULT IN LOW TEMPS IN THE
LOW TO MID 20S ACROSS THE AREA THURSDAY NIGHT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 255 PM MONDAY...
HIGH PRESSURE WILL BUILD EAST TOWARD NC ON FRIDAY...HOWEVER COLD AIR
ADVECTING INTO THE REGION WILL RESULT IN HIGHS ONLY IN THE MID 30S
NORTH TO AROUND 40 DEGREES SOUTHWEST. OVERNIGHT LOWS IN THE UPPER
TEENS TO LOW 20S EXPECTED FRIDAY NIGHT. BOTH THE GFS AND THE ECMWF
PREDICT HIGH PRESSURE TO TRAVERSE THE GREAT LAKES REGION DURING THIS
TIME PERIOD...RIDGING SOUTH INTO CENTRAL NC ON SATURDAY NIGHT AND
LINGERING THROUGH THE WEEKEND. THE BIG QUESTION WILL BE HOW LONG THE
WEDGE AIRMASS LINGERS OVER THE NORTHWEST...AND HOW THAT WILL IMPACT
BOTH TEMPERATURES AND WEATHER TOWARD THE END OF THE WEEKEND AND INTO
MONDAY. WITH SIGNIFICANT MODEL DIFFERENCES DURING THIS PART OF THE
FORECAST...CONFIDENCE REMAINS LOW. GENERALLY...EXPECT INCREASING
PRECIPITATION CHANCES FROM WEST TO EAST THROUGH MONDAY WITH
GRADUALLY MODERATING TEMPERATURES FROM UPPER 30S NW TO LOW 40S SE ON
SATURDAY TO MID 50S NW TO POSSIBLY LOW 60S SOUTH ON MONDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 100 PM MONDAY...
PRIMARY AVIATION CONCERN NEXT 24 HRS: MVFR CIGS AT RDU/RWI/FAY
THROUGH EARLY THIS EVENING... THEN RETURNING TO INT/GSO TOWARD
MIDNIGHT... AND RETURNING TO RDU/RWI/FAY TUE MORNING.
A COLD FRONT HAS SETTLED SOUTHEAST OF CENTRAL NC EARLY THIS
AFTERNOON... AFTER BRINGING PATCHY RAIN AND SUB-VFR CIGS TO AREA
TERMINALS. CIGS AT INT/GSO HAVE RISEN TO VFR AS CHILLY HIGH PRESSURE
BEGINS TO BUILD IN FROM THE NORTH AND NW... HOWEVER MVFR CIGS
PERSIST AT RDU/FAY/RWI. AT INT/GSO... VFR CONDITIONS WILL HOLD UNTIL
AROUND 05Z OR 06Z... WHEN MVFR OR IFR CIGS WILL RETURN AND LIKELY
LINGER THROUGH THE END OF THE TAF VALID PERIOD. AT RDU/FAY/RWI...
MVFR CIGS SHOULD PERSIST UNTIL THE 02Z-05Z TIME FRAME... WHEN CIGS
SHOULD IMPROVE TO VFR. OCCASIONAL GUSTS ARE ALSO EXPECTED AT THESE
THREE SITES THIS AFTERNOON. VFR CONDITIONS SHOULD HOLD OVERNIGHT AT
THESE 3 SITES THROUGH DAYBREAK TUE AS THE HIGH PRESSURE CONTINUES TO
BUILD IN... BUT THEN AFTER 13Z TUE... AN APPROACHING DISTURBANCE
ALOFT TRACKING ACROSS THE GULF AND SOUTHEAST STATES WILL BRING A
RETURN TO MVFR OR IFR CONDITIONS STARTING MID MORNING TUE. A LITTLE
LIGHT SNOW IS POSSIBLE STARTING TUE MORNING... ESPECIALLY AT FAY...
HOWEVER AMOUNTS SHOULD BE VERY LIGHT... AND WHILE VSBYS MAY DROP TO
MVFR... THERE IS TOO MUCH UNCERTAINTY AT THIS RANGE TO INCLUDE THIS
IN THE TAFS AT THIS TIME... BUT STAY TUNED.
LOOKING BEYOND 18Z TUE... CONFIDENCE IS NOT HIGH IN THE DETAILS OF
THE FORECAST THROUGH MID WEEK... ALTHOUGH THE WEATHER IS LIKELY TO
REMAIN UNSETTLED. THE FRONTAL ZONE HOLDS JUST TO OUR SOUTHEAST...
WITH WAVES OF LOW PRESSURE OF VARYING STRENGTH TRACKING ALONG THE
FRONTAL ZONE. VFR CONDITIONS SHOULD BE NOTED AT ALL SITES BRIEFLY
TUE EVENING/NIGHT... BUT IFR FOG IS POSSIBLE WITH A MOIST AIR MASS
IN PLACE. THE STRONGEST LOW PRESSURE WAVE OF THIS SERIES WILL PASS
JUST TO OUR SOUTHEAST LATE WED THROUGH THU MORNING... AND THIS WILL
BRING THE NEXT GREATEST CHANCE FOR SUB-VFR CONDITIONS AND
PRECIPITATION (LIKELY A WINTRY MIX) MAINLY WED EVENING INTO EARLY
THU MORNING. SUB-IFR CONDITIONS MAY HOLD AT INT/GSO WITH LOW CLOUDS
AND FOG THU INTO FRI... WHILE VFR CONDITIONS ARE NOTED AT OTHER
SITES. CHILLY HIGH PRESSURE BUILDING IN FOR THE WEEKEND MAY FINALLY
ENSURE A PERIOD OF VFR CONDITIONS AT ALL SITES SATURDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLS/GIH
NEAR TERM...CBL/BLS/MLM
SHORT TERM...KC
LONG TERM...KC
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
100 PM EST MON FEB 23 2015
.SYNOPSIS..A COLD FRONT WILL SETTLE SOUTHEAST OF THE AREA THIS
AFTERNOON. A WEAK WAVE OF LOW PRESSURE WILL TRACK NORTHEASTWARD
ALONG THE FRONT TONIGHT THROUGH TUESDAY... AS ARCTIC HIGH PRESSURE
BUILDS INTO THE AREA FROM THE NORTH. A SECOND STRONGER LOW PRESSURE
AREA WILL TRACK ALONG THE FRONT MIDWEEK... MOVING JUST SOUTHEAST OF
THE AREA WEDNESDAY NIGHT THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM MONDAY...
A LOW AMPLITUDE SHORTWAVE AND ASSOCIATED WEAK SURFACE LOW ARE
DEPARTING THE SC COAST THIS MORNING. ANAFRONTAL PRECIP MAINLY
SOUTHEAST OF THE TRIANGLE AREA WILL ALSO CONTINUE TO EXIT TO THE
EAST THROUGH EARLY AFTERNOON. WEAK COLD ADVECTION WILL PERSIST THIS
AFTERNOON BEFORE THE STRONGER SURGE OCCURS THIS EVENING AHEAD THE
ARCTIC HIGH BUILDING ACROSS THE CENTRAL APPALACHIANS. DUE TO THE
DELAYED ARRIVAL OF COLDER LOW-LEVEL AIR...THE WETBULB FREEZING LINE
IS STILL WELL TO OUR NORTH IN CENTRAL VA AND BY THE TIME IT SINKS
SOUTH IN THE NORTHERN COASTAL PLAIN THIS AFTERNOON... ALL DEEPER
MOISTURE AND PRECIP WILL EITHER HAVE DEPARTED OR PRECIP WON`T BE OF
SUFFICIENT INTENSITY TO CAUSE WETBULBING OR ANY WINTRY IMPACTS.
LATEST GUIDANCE REFLECTS THIS. WILL KEEP THE GENERAL TREND OF POPS
GOING AND JUST MAKE SOME ALTERATIONS TO ACCOUNT FOR LATEST
RADAR....WITH POPS ENDING AFTER 18Z. WILL ALSO HAVE AN EYE ON THE
POTENTIAL FOR A MESOSCALE BAND OF SHALLOW MOISTURE AND PRECIP (MOST
LIKELY SLEET BASED ON TEMPS AROUND -10C IN THE SHALLOW SATURATED
LAYER) IN THE 21Z TO 03Z TIME FRAME...THOUGH NO IMPACT WOULD BE
EXPECTED AT THIS TIME. HI-RES MODELS ARE STILL SPLIT ON WHETHER OR
NOT THIS WILL DEVELOP...BUT MODELS HAVE BEEN SHOWING SOMETHING OF
THIS NATURE FOR MULTIPLE RUNS.
REGARDING TEMPS...THICKNESSES WILL STEADILY FALL THROUGHOUT THE DAY
IN THE NORTHEAST FLOW...SO FOR MANY LOCATIONS HIGHS IN THE UPPER 30S
NORTH TO MID 40S SOUTH HAVE ALREADY OCCURRED. THE HRRR SHOWS SOME
INTERMITTENT BREAKS IN CLOUDS OVER THE THE NORTHWEST PIEDMONT WITH
WESTERLY FLOW ALOFT AND NOT AS MUCH LOW-LEVEL MOISTURE THERE. NOT
CONFIDENT IN THE UPPER 40S THE HRRR GIVES...BUT THERE COULD BE A
LITTLE WARMING THROUGH EARLY AFTERNOON.
TONIGHT: THE SECOND BATCH OF S/W ENERGY MOVES INTO THE AREA BETWEEN
06 TO 12Z TUESDAY. RESULTANT WEAK DPVA AND SHALLOW ISENTROPIC
UPGLIDE WILL RE-NEW/DEEPEN SATURATION ALOFT TO SUPPORT SOME LIGHT
SNOW AND FLURRIES INTO THE AREA AROUND DAYBREAK ACROSS THE WESTERN
AND SOUTHERN PORTIONS OF THE FORECAST AREA. MODELS ARE ONLY
GENERATING A HUNDREDTH OR TWO ACROSS THE AREA SO NO ACCUMULATION ARE
EXPECTED. CAA WILL GOVERN LOWS TONIGHT...RANGING FROM UPPER TEENS
ACROSS THE NE TO MID 20S SOUTH.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 330 AM MONDAY...
TRANSITORY ARCTIC HIGH PRESSURE WILL HAVE SETTLED ACROSS THE HEART
OF CENTRAL NC BY TUESDAY MORNING. THIS HIGH PRESSURE WILL BE NUDGED
OFFSHORE BY LATE DAY AS A FAST MOVING SHORT WAVE MOVES EAST ACROSS
THE AREA. BRIEF SOUTHERLY FLOW AND WEAK SUPPORT ALOFT WILL
POTENTIALLY PRODUCE SOME LIGHT SNOW/FLURRIES...MAINLY ACROSS THE
SOUTHERN TIER AND THE WESTERN PIEDMONT TUESDAY MORNING THROUGH
AROUND MID DAY. OTHERWISE...SKIES WILL REMAIN BE MOSTLY CLOUDY
THROUGH THE DAY WITH HIGHS PEAKING IN THE MID TO UPPER 30S. MINOR
MODERATION IN MIN TEMPS IS EXPECTED TUE NIGHT WITH DOWNSLOPE WARMING
IN GENERALLY WESTERLY LOW LEVEL FLOW AIDED BY STREAMING MID TO HIGH
CLOUDINESS ALOFT IN THE FAST CONFLUENT FLOW. MINS WILL BE MOSTLY IN
THE MID 20S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 330 AM MONDAY...
A SOUTHERN STREAM SHORT WAVE MOVING ACROSS THE SOUTHEASTERN GULF
STATES HAS BEEN ADVERTISED FOR THE MIDWEEK FOR THE PAST FEW DAYS.
THIS SHORT WAVE WILL INDUCE CYCLOGENESIS ALONG THE SOUTHERN STREAM
MOISTURE PLUME/STALLED FRONTAL ZONE. THE RESULTING LOW WILL MOVE
NORTHEAST ACROSS NORTHERN FLORIDA AND GRAZE THE AREA AS IT MOVES OFF
INTO THE MID ATLANTIC. RAIN WILL SPREAD INTO THE SOUTHERN TIER AS
EARLY AS WEDNESDAY AFTERNOON...WITH BETTER CHANCES DURING THE
OVERNIGHT. COLD AIR WILL BE SURGING SOUTH BEHIND THE LOW...AND
EXPECT A SOUTHERLY TRANSITION TO SNOW OVERNIGHT AS MINS FALL INTO
THE MID AND UPPER 20S. A CHANCE OF SNOW WILL LINGER INTO THURSDAY
MORNING EAST OF INTERSTATE 95...OTHERWISE SKIES WILL REMAIN CLOUDY
WITH HIGHS SUFFERING ANOTHER SETBACK AS REINFORCING HIGH PRESSURE
AGAIN SETTLES DOWN THE COAST. THURSDAYS HIGHS WILL BE IN THE UPPER
30S NORTH TO LOWER 40S SOUTH.
HAVE LITTLE CONFIDENCE IN NAILING DOWN THE FEATURES OF POTENTIAL
PRECIP PRODUCING SYSTEMS AS THE WEEKEND APPROACHES IN THIS STUBBORN
SPLIT FLOW REGIME...I.E. EVOLUTION AND TIMING OF NORTHERN VS
SOUTHERN STREAM FEATURES AND THEIR REFUSAL TO COME INTO PHASE.
CONFIDENCE IS HIGH THAT HIGHS FRIDAY THROUGH SUNDAY WILL REMAIN
WELL BELOW NORMAL...GENERALLY IN THE UPPER 30S TO LOWER 40S FRIDAY
AND SATURDAY...AND LOW AMPLITUDE RIDGING LATE THIS WEEKEND WILL
PRODUCE A WARMUP SUNDAY...WITH PERHAPS NEAR NORMAL HIGHS ON MONDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 100 PM MONDAY...
PRIMARY AVIATION CONCERN NEXT 24 HRS: MVFR CIGS AT RDU/RWI/FAY
THROUGH EARLY THIS EVENING... THEN RETURNING TO INT/GSO TOWARD
MIDNIGHT... AND RETURNING TO RDU/RWI/FAY TUE MORNING.
A COLD FRONT HAS SETTLED SOUTHEAST OF CENTRAL NC EARLY THIS
AFTERNOON... AFTER BRINGING PATCHY RAIN AND SUB-VFR CIGS TO AREA
TERMINALS. CIGS AT INT/GSO HAVE RISEN TO VFR AS CHILLY HIGH PRESSURE
BEGINS TO BUILD IN FROM THE NORTH AND NW... HOWEVER MVFR CIGS
PERSIST AT RDU/FAY/RWI. AT INT/GSO... VFR CONDITIONS WILL HOLD UNTIL
AROUND 05Z OR 06Z... WHEN MVFR OR IFR CIGS WILL RETURN AND LIKELY
LINGER THROUGH THE END OF THE TAF VALID PERIOD. AT RDU/FAY/RWI...
MVFR CIGS SHOULD PERSIST UNTIL THE 02Z-05Z TIME FRAME... WHEN CIGS
SHOULD IMPROVE TO VFR. OCCASIONAL GUSTS ARE ALSO EXPECTED AT THESE
THREE SITES THIS AFTERNOON. VFR CONDITIONS SHOULD HOLD OVERNIGHT AT
THESE 3 SITES THROUGH DAYBREAK TUE AS THE HIGH PRESSURE CONTINUES TO
BUILD IN... BUT THEN AFTER 13Z TUE... AN APPROACHING DISTURBANCE
ALOFT TRACKING ACROSS THE GULF AND SOUTHEAST STATES WILL BRING A
RETURN TO MVFR OR IFR CONDITIONS STARTING MID MORNING TUE. A LITTLE
LIGHT SNOW IS POSSIBLE STARTING TUE MORNING... ESPECIALLY AT FAY...
HOWEVER AMOUNTS SHOULD BE VERY LIGHT... AND WHILE VSBYS MAY DROP TO
MVFR... THERE IS TOO MUCH UNCERTAINTY AT THIS RANGE TO INCLUDE THIS
IN THE TAFS AT THIS TIME... BUT STAY TUNED.
LOOKING BEYOND 18Z TUE... CONFIDENCE IS NOT HIGH IN THE DETAILS OF
THE FORECAST THROUGH MID WEEK... ALTHOUGH THE WEATHER IS LIKELY TO
REMAIN UNSETTLED. THE FRONTAL ZONE HOLDS JUST TO OUR SOUTHEAST...
WITH WAVES OF LOW PRESSURE OF VARYING STRENGTH TRACKING ALONG THE
FRONTAL ZONE. VFR CONDITIONS SHOULD BE NOTED AT ALL SITES BRIEFLY
TUE EVENING/NIGHT... BUT IFR FOG IS POSSIBLE WITH A MOIST AIR MASS
IN PLACE. THE STRONGEST LOW PRESSURE WAVE OF THIS SERIES WILL PASS
JUST TO OUR SOUTHEAST LATE WED THROUGH THU MORNING... AND THIS WILL
BRING THE NEXT GREATEST CHANCE FOR SUB-VFR CONDITIONS AND
PRECIPITATION (LIKELY A WINTRY MIX) MAINLY WED EVENING INTO EARLY
THU MORNING. SUB-IFR CONDITIONS MAY HOLD AT INT/GSO WITH LOW CLOUDS
AND FOG THU INTO FRI... WHILE VFR CONDITIONS ARE NOTED AT OTHER
SITES. CHILLY HIGH PRESSURE BUILDING IN FOR THE WEEKEND MAY FINALLY
ENSURE A PERIOD OF VFR CONDITIONS AT ALL SITES SATURDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLS/GIH
NEAR TERM...CBL/BLS
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1015 AM EST MON FEB 23 2015
.SYNOPSIS..AN AREA OF LOW PRESSURE AND ATTENDANT COLD FRONT WILL PUSH
SOUTH AND EAST OF THE AREA LATER THIS MORNING. ARCTIC HIGH
PRESSURE WILL BUILD INTO OUR AREA THIS AFTERNOON THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM MONDAY...
A LOW AMPLITUDE SHORTWAVE AND ASSOCIATED WEAK SURFACE LOW ARE
DEPARTING THE SC COAST THIS MORNING. ANAFRONTAL PRECIP MAINLY
SOUTHEAST OF THE TRIANGLE AREA WILL ALSO CONTINUE TO EXIT TO THE
EAST THROUGH EARLY AFTERNOON. WEAK COLD ADVECTION WILL PERSIST THIS
AFTERNOON BEFORE THE STRONGER SURGE OCCURS THIS EVENING AHEAD THE
ARCTIC HIGH BUILDING ACROSS THE CENTRAL APPALACHIANS. DUE TO THE
DELAYED ARRIVAL OF COLDER LOW-LEVEL AIR...THE WETBULB FREEZING LINE
IS STILL WELL TO OUR NORTH IN CENTRAL VA AND BY THE TIME IT SINKS
SOUTH IN THE NORTHERN COASTAL PLAIN THIS AFTERNOON... ALL DEEPER
MOISTURE AND PRECIP WILL EITHER HAVE DEPARTED OR PRECIP WON`T BE OF
SUFFICIENT INTENSITY TO CAUSE WETBULBING OR ANY WINTRY IMPACTS.
LATEST GUIDANCE REFLECTS THIS. WILL KEEP THE GENERAL TREND OF POPS
GOING AND JUST MAKE SOME ALTERATIONS TO ACCOUNT FOR LATEST
RADAR....WITH POPS ENDING AFTER 18Z. WILL ALSO HAVE AN EYE ON THE
POTENTIAL FOR A MESOSCALE BAND OF SHALLOW MOISTURE AND PRECIP (MOST
LIKELY SLEET BASED ON TEMPS AROUND -10C IN THE SHALLOW SATURATED
LAYER) IN THE 21Z TO 03Z TIME FRAME...THOUGH NO IMPACT WOULD BE
EXPECTED AT THIS TIME. HI-RES MODELS ARE STILL SPLIT ON WHETHER OR
NOT THIS WILL DEVELOP...BUT MODELS HAVE BEEN SHOWING SOMETHING OF
THIS NATURE FOR MULTIPLE RUNS.
REGARDING TEMPS...THICKNESSES WILL STEADILY FALL THROUGHOUT THE DAY
IN THE NORTHEAST FLOW...SO FOR MANY LOCATIONS HIGHS IN THE UPPER 30S
NORTH TO MID 40S SOUTH HAVE ALREADY OCCURRED. THE HRRR SHOWS SOME
INTERMITTENT BREAKS IN CLOUDS OVER THE THE NORTHWEST PIEDMONT WITH
WESTERLY FLOW ALOFT AND NOT AS MUCH LOW-LEVEL MOISTURE THERE. NOT
CONFIDENT IN THE UPPER 40S THE HRRR GIVES...BUT THERE COULD BE A
LITTLE WARMING THROUGH EARLY AFTERNOON.
TONIGHT: THE SECOND BATCH OF S/W ENERGY MOVES INTO THE AREA BETWEEN
06 TO 12Z TUESDAY. RESULTANT WEAK DPVA AND SHALLOW ISENTROPIC
UPGLIDE WILL RE-NEW/DEEPEN SATURATION ALOFT TO SUPPORT SOME LIGHT
SNOW AND FLURRIES INTO THE AREA AROUND DAYBREAK ACROSS THE WESTERN
AND SOUTHERN PORTIONS OF THE FORECAST AREA. MODELS ARE ONLY
GENERATING A HUNDREDTH OR TWO ACROSS THE AREA SO NO ACCUMULATION ARE
EXPECTED. CAA WILL GOVERN LOWS TONIGHT...RANGING FROM UPPER TEENS
ACROSS THE NE TO MID 20S SOUTH.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 330 AM MONDAY...
TRANSITORY ARCTIC HIGH PRESSURE WILL HAVE SETTLED ACROSS THE HEART
OF CENTRAL NC BY TUESDAY MORNING. THIS HIGH PRESSURE WILL BE NUDGED
OFFSHORE BY LATE DAY AS A FAST MOVING SHORT WAVE MOVES EAST ACROSS
THE AREA. BRIEF SOUTHERLY FLOW AND WEAK SUPPORT ALOFT WILL
POTENTIALLY PRODUCE SOME LIGHT SNOW/FLURRIES...MAINLY ACROSS THE
SOUTHERN TIER AND THE WESTERN PIEDMONT TUESDAY MORNING THROUGH
AROUND MID DAY. OTHERWISE...SKIES WILL REMAIN BE MOSTLY CLOUDY
THROUGH THE DAY WITH HIGHS PEAKING IN THE MID TO UPPER 30S. MINOR
MODERATION IN MIN TEMPS IS EXPECTED TUE NIGHT WITH DOWNSLOPE WARMING
IN GENERALLY WESTERLY LOW LEVEL FLOW AIDED BY STREAMING MID TO HIGH
CLOUDINESS ALOFT IN THE FAST CONFLUENT FLOW. MINS WILL BE MOSTLY IN
THE MID 20S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 330 AM MONDAY...
A SOUTHERN STREAM SHORT WAVE MOVING ACROSS THE SOUTHEASTERN GULF
STATES HAS BEEN ADVERTISED FOR THE MIDWEEK FOR THE PAST FEW DAYS.
THIS SHORT WAVE WILL INDUCE CYCLOGENESIS ALONG THE SOUTHERN STREAM
MOISTURE PLUME/STALLED FRONTAL ZONE. THE RESULTING LOW WILL MOVE
NORTHEAST ACROSS NORTHERN FLORIDA AND GRAZE THE AREA AS IT MOVES OFF
INTO THE MID ATLANTIC. RAIN WILL SPREAD INTO THE SOUTHERN TIER AS
EARLY AS WEDNESDAY AFTERNOON...WITH BETTER CHANCES DURING THE
OVERNIGHT. COLD AIR WILL BE SURGING SOUTH BEHIND THE LOW...AND
EXPECT A SOUTHERLY TRANSITION TO SNOW OVERNIGHT AS MINS FALL INTO
THE MID AND UPPER 20S. A CHANCE OF SNOW WILL LINGER INTO THURSDAY
MORNING EAST OF INTERSTATE 95...OTHERWISE SKIES WILL REMAIN CLOUDY
WITH HIGHS SUFFERING ANOTHER SETBACK AS REINFORCING HIGH PRESSURE
AGAIN SETTLES DOWN THE COAST. THURSDAYS HIGHS WILL BE IN THE UPPER
30S NORTH TO LOWER 40S SOUTH.
HAVE LITTLE CONFIDENCE IN NAILING DOWN THE FEATURES OF POTENTIAL
PRECIP PRODUCING SYSTEMS AS THE WEEKEND APPROACHES IN THIS STUBBORN
SPLIT FLOW REGIME...I.E. EVOLUTION AND TIMING OF NORTHERN VS
SOUTHERN STREAM FEATURES AND THEIR REFUSAL TO COME INTO PHASE.
CONFIDENCE IS HIGH THAT HIGHS FRIDAY THROUGH SUNDAY WILL REMAIN
WELL BELOW NORMAL...GENERALLY IN THE UPPER 30S TO LOWER 40S FRIDAY
AND SATURDAY...AND LOW AMPLITUDE RIDGING LATE THIS WEEKEND WILL
PRODUCE A WARMUP SUNDAY...WITH PERHAPS NEAR NORMAL HIGHS ON MONDAY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 620 AM MONDAY...
24HR TAF PERIOD: UPPER LEVEL DISTURBANCES TRACKING THROUGH THE
SOUTHEAST US THIS MORNING WILL SUPPORT WEAK ISENTROPIC LIFT AS A
WEAK AREA OF LOW PRESSURE DEVELOPS ALONG THE SOUTHWARD SINKING COLD
FRONT. THE STEADIER...MORE WIDESPREAD RAIN WILL TRACK ACROSS THE SE
PORTIONS OF THE AREA AND WILL AFFECT KFAY THROUGH 15Z-17Z. RDU AND
RWI WILL SEE SOME LIGHT PATCHY RAIN DURING THE SAME PERIOD...WHILE
KGSO AND KINT WILL LIKELY REMAIN DRY. CIGS ARE EXPECTED TO GENERALLY
RANGE FROM MVFR NW TO POSSIBLY IFR/LIFR SOUTHEAST. STRONG CAA DURING
THE DAY WILL RESULT IN NELY WIND GUSTS OF 20 TO 25KTS STRONGEST AT
KFAY. ADDITIONALLY...COULD SEE A BRIEF CHANGEOVER TO SNOW OR SLEET
THIS AFTERNOON AS COLD AIR BUILDS INTO THE AREA FROM THE NORTH.
LOW-LEVEL DRY AIR FEED SHOULD ALLOW CIGS TO LIFT TO VFR AT KGSO/KINT
BY THE AFTERNOON... WITH KRDU/KFAY/KRWI DELAYED UNTIL THE EVENING.
SUB-VFR CONDITIONS COULD SPREAD BACK INTO THE KINT AND KGSO BETWEEN
06 TO 12Z TUESDAY AS ANOTHER BATCH OF UPPER DISTURBANCES MOVES INTO
THE REGION ALONG WITH SNOW FLURRIES.
OUTLOOK: COULD SEE A PERIOD OF IFR TO MVFR CONDITIONS WITH FLURRIES
ON TUESDAY AS ANOTHER UPPER LEVEL DISTURBANCE TRACKS THROUGH THE
REGION. AN AREA OF LOW PRESSURE TRACKING NE FROM THE GULF OF MEXICO
TO THE SOUTHEAST COAST MAY SPREAD PRECIPITATION WITH ADVERSE
AVIATION CONDITIONS INTO THE AREA WEDNESDAY NIGHT INTO THURSDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL/BLS
NEAR TERM...CBL/BLS
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
332 AM EST MON FEB 23 2015
.SYNOPSIS...
RAIN ASSOCIATED WITH A COLD FRONTAL PASSAGE OVERNIGHT WILL BE
LIGHT TONIGHT. WEAK LOW PRESSURE WILL MOVE ALONG THE STALLED
FRONT LATER TODAY...SPREADING MORE SIGNIFICANT RAIN NORTHWARD.
COLD AIR WILL RETURN THIS EVENING AS ARCTIC HIGH PRESSURE SNEAKS
BACK ACROSS THE REGION. COLD AND UNSETTLED WEATHER IS EXPECTED
DURING THE UPCOMING WEEK AS CHILLY HIGH PRESSURE AND GULF MOISTURE
INTERACT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM SUNDAY...SCATTERED AREAS OF RAIN IS LEADING A FRONTAL
BOUNDARY THAT WILL SLOWLY PUSH OFF THE COAST BY MORNING. THE AREA
OF RAIN IS PRODUCING TOTAL OF LESS THAN A TENTH OF AN INCH. THE
LATEST RUN OF THE HRRR IS SHOWING THE COVERAGE OF THE RAIN
BECOMING MORE WIDESPREAD OVERNIGHT. TEMPERATURES ARE EXPECTED TO
FALL ONLY TO AROUND 40 IN THE NORTHWEST TO THE UPPER 40S SOUTH AND
WEST OF MYRTLE BEACH.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...PERIOD BEGINS WITH FRONT STALLED ACROSS THE FL
PENINSULA BUT ITS EXACT LOCATION REMAINS SOMEWHAT IN QUESTION. MOST
OF THE GUIDANCE HAS THIS FRONT STALLED ACROSS CENTRAL OR SOUTHERN FL
WITH ONLY THE NAM KEEPING IT FARTHER NORTH. WEAK SURFACE WAVE WILL
DEVELOP ALONG THE FRONT AND MOVE SLOWLY EAST-NORTHEAST. THIS FEATURE
HELPS SPREAD PRECIP OVER THE AREA TUE INTO TUE NIGHT AS IT PASSES
OFF THE CAROLINA COAST. ISENTROPIC LIFT WILL BE ONGOING TUE IN A
ENVIRONMENT FULL OF LOW LEVEL MOISTURE. THERMAL PROFILES IN MOST OF
THE GUIDANCE SUPPORTS ALL SNOW AT FIRST. SOUTHERN AREAS WILL
TRANSITION TO A WINTRY MIX WHILE NORTHERN LOCATIONS REMAIN IN AN ALL
FROZEN REGIME. AT THIS POINT SOUNDINGS DO NOT SUPPORT SIGNIFICANT
AMOUNTS OF ZR BUT MUCH CAN CHANGE BETWEEN NOW AND THEN. THE BULK OF
THE MOISTURE WILL REMAIN SOUTH AND EAST OF THE AREA WITH INLAND MOST
ZONES LIKELY TO STAY DRY BUT UNDER CLOUDY SKIES.
WED STARTS OFF DRY BUT NEXT SOUTHERN STREAM SYSTEM...WHICH IS MORE
POTENT THAN THE PREVIOUS ONE...WILL BE MOVING ALONG THE GULF COAST.
TRACK OF THE SURFACE FEATURE...ALONG THE REMAINS OF THE STALLED
SURFACE BOUNDARY...WILL BE ACROSS NORTHERN FL WED AND UP THE EAST
COAST WED NIGHT. THE QUESTION IS HOW CLOSE WILL THE LOW PASSES. THE
GFS/NAM/CANADIAN HAVE A WEAKER SHORTWAVE COMPARED TO THE ECMWF AND
THUS A SLIGHTLY LESS AMPLIFIED MID LEVEL PATTERN. THIS KEEPS THE LOW
FARTHER OFF THE COAST WHICH RESULTS IN A LITTLE LESS PRECIP IN THE
AREA. CONTINUE TO FAVOR THIS SOLUTION GIVEN THE NATURE OF THE
PATTERN AND THE LOCATION OF THE BAROCLINIC ZONE. WORTH NOTING THAT
EITHER SOLUTION OPENS UP THE POTENTIAL FOR FROZEN PRECIP LATE WED
NIGHT AS STRONG NORTHERLY FLOW ON THE WEST SIDE OF THE DEEPENING LOW
BRINGS COLDER AIR INTO THE REGION.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...DEEPENING LOW PRESSURE WILL BE PASSING OFF THE
CAROLINA COAST AS THE PERIOD BEGINS WITH PRECIP LIKELY ONGOING
ACROSS THE AREA. THERE IS POTENTIAL FOR FROZEN PRECIP EARLY
THU...BUT UNCERTAINTY REMAINS HIGH. THE FIRST ISSUE TO SORT OUT IS
HOW MUCH PRECIP WILL BE LINGERING ACROSS THE AREA. GFS AND CANADIAN
SOLUTIONS...WHICH PASS THE LOW FARTHER OFF THE COAST INDICATE PRECIP
WILL BE WINDING DOWN AS THE PERIOD BEGINS...THOUGH WITH COLDER AIR
ALREADY FILTERING IN AT THE LOWER LEVELS. THE ECMWF HAS THE LOW
CLOSER TO THE COAST...WHICH KEEPS PRECIP IN THE FORECAST LONGER BUT
BECAUSE IT IS SLOWER IT HAS TEMPS SLIGHTLY WARMER THU MORNING. AS IS
THE CASE WITH THE FASTER SOLUTION COLDER/DRIER LOW LEVEL AIR DOES
WORK ITS WAY IN AS THE PRECIP IS ENDING.
MODELS CONTINUE TO TREND DRIER FOR THE END OF THE WEEK WITH ALL OF
THE MEDIUM RANGE NOW SHOWING A SPRAWLING 1040MB HIGH DROPPING IN
FROM THE UPPER MIDWEST FRI. THE HIGH SHIFTS OVER NEW ENGLAND
SAT...EXPANDING DOWN THE EAST ON SUN BEFORE FINALLY PUSHING EAST
MON. THE AGREEMENT BETWEEN THE GFS/ECMWF/CANADIAN IS ACTUALLY
QUITE SCARY GIVEN THE MIDWEEK NIGHTMARE BUT THE CONTINUED TREND OF
DRYING THE FORECAST DOES INCREASE CONFIDENCE SO HAVE TRENDED LATE
WEEK FORECAST IN THIS DIRECTION. TEMPERATURES BELOW TO WELL BELOW
CLIMO FOR MUCH OF THE PERIOD WILL APPROACH SEASONABLE AS THE
PERIOD ENDS.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...EXPECT PCPN IN THE FORM OF LIGHT RAIN TO STREAM ACROSS
THE FORECAST AREA BOTH ALONG AND BEHIND THE COLD FRONTAL
BOUNDARY. MOISTURE WILL CONTINUE TO FEED ALONG THE FRONT AS
ASSOCIATED UPPER LEVEL DISTURBANCE RIDES ALONG THE FRONT AND WILL
ENHANCE THE RAINFALL DURING THE PRE-DAWN MON HOURS INTO DAYTIME
MON MORNING. IFR AND POSSIBLY LIFR FROM BOTH CEILINGS AND VSBY
FROM BR AND FG WILL LIKELY DOMINATE ALL TERMINALS THROUGH THE PRE-
DAWN MON HOURS...WITH A SLOW IMPROVEMENT DURING DAYTIME MON
MORNING INTO THE AFTERNOON AS THE FRONT DROPS FURTHER
SOUTH...ENDING THE THREAT FOR PCPN WITH BOTH VSBY AND CEILINGS
IMPROVING. IMMEDIATELY AFTER THE CFP...WINDS WILL VEER TO 360-020
AT 5 TO 10 KT...INCREASING DURING MONDAY TO 10 TO 20 KT...WITH
SOME GUSTS IN THE 20S ESPECIALLY ACROSS THE COASTAL TERMS. THIS IN
RESPONSE TO THE COMBINED EFFORTS OF COLD AIR ADVECTION AND A
TIGHTENED SFC PRESSURE GRADIENT.
EXTENDED OUTLOOK...WAVES OF LOW PRESSURE TO AFFECT THE LOCAL AREA
DURING THE EXTENDED PERIOD...RESULTING WITH POSSIBLE LIFR/IFR/MVFR
CONDITIONS.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM SUNDAY...WINDS ARE RELATIVELY LIGHT OVER THE WATERS
WITH SEAS RANGING FROM 2 TO 4 FEET. FRYING PAN SHOALS IS NOW
REPORTING SEAS DOWN TO 5 FEET JUST OUTSIDE THE COASTAL WATERS. A
LIGHT RAIN IS EXPECTED OVERNIGHT AS A COLD FRONT SLOWLY
APPROACHES THE WATERS BY DAYBREAK.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...STRONG WINDS PRIOR TO THE START OF THE PERIOD
WILL HAVE BUILT SEAS HIGH ENOUGH TO LIKELY REQUIRE SCA INTO AT LEAST
THE FIRST HALF OF TUE MORNING. NORTHERLY FLOW WILL BE WEAKENING TUE
AS SURFACE HIGH TO THE NORTH WEAKENS AND GRADIENT GRADUALLY RELAXES.
LOW PRESSURE WILL PASS SOUTHEAST OF THE WATERS TUE EVENING...BACKING
WINDS FROM NORTHEAST TO WEST-SOUTHWEST. GRADIENT WILL FURTHER WEAKEN
TUE NIGHT AND SPEEDS WILL DROP BELOW 10 KT. PERIOD OF LIGHT OFFSHORE
FLOW WILL BE SHORT LIVED AS NEXT SOUTHERN STREAM SYSTEM BEGINS TO
AFFECT THE GRADIENT WED. NORTHERLY FLOW WILL DEVELOP AS EARLY AS
MIDDAY WED WITH SPEEDS INCREASING WED NIGHT AHEAD OF ADVANCING
LOW...POSSIBLY REQUIRING HEADLINES WED NIGHT.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...STRONG NORTHEAST FLOW IN THE WAKE OF EXITING LOW
PRESSURE SYSTEMS MAY REQUIRE SCA HEADLINES FOR MUCH IF NOT ALL OF
THE PERIOD. THE FIRST LOW WILL BE LIFTING NORTHEAST AS THE PERIOD
BEGINS. THE SECOND WILL PASS A BIT FARTHER OFFSHORE FRI MORNING BUT
WILL BE A LITTLE STRONGER. THESE SYSTEMS ALONG WITH A SPRAWLING
1040MB HIGH BUILDING IN FROM THE UPPER MIDWEST WILL MAINTAIN
NORTHEAST FLOW AROUND 20 KT AND KEEP SEAS OVER 6 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 2 PM EST
TUESDAY FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...DRH
SHORT TERM...III
LONG TERM...III
AVIATION...DCH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
107 AM EST MON FEB 23 2015
.SYNOPSIS...
A MILD AND MOIST AIR MASS WILL LIE ACROSS THE AREA INTO TONIGHT.
RAIN ASSOCIATED WITH A COLD FRONTAL PASSAGE WILL BE LIGHT
TONIGHT...BUT WEAK LOW PRESSURE WILL MOVE ALONG THE STALLED
FRONT...SPREADING MORE SIGNIFICANT RAIN NORTHWARD ON MONDAY. COLD
AIR WILL RETURN LATE MONDAY AS ARCTIC HIGH PRESSURE SNEAKS BACK
ACROSS THE REGION INTO TUE. COLD AND UNSETTLED WEATHER IS EXPECTED
DURING THE UPCOMING WEEK AS CHILLY HIGH PRESSURE AND GULF MOISTURE
INTERACT.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 930 PM SUNDAY...SCATTERED AREAS OF RAIN IS LEADING A FRONTAL
BOUNDARY THAT WILL SLOWLY PUSH OFF THE COAST BY MORNING. THE AREA
OF RAIN IS PRODUCING TOTAL OF LESS THAN A TENTH OF AN INCH. THE
LATEST RUN OF THE HRRR IS SHOWING THE COVERAGE OF THE RAIN
BECOMING MORE WIDESPREAD OVERNIGHT. TEMPERATURES ARE EXPECTED TO
FALL ONLY TO AROUND 40 IN THE NORTHWEST TO THE UPPER 40S SOUTH AND
WEST OF MYRTLE BEACH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
AS OF 330 PM SUNDAY...WAVE OF LOW PRESSURE RIDING ALONG
LINGERING FRONT MON MORNING WILL MOVE OUT OF AREA MON AFTN AS HIGH
PRESSURE BUILDS DOWN FROM THE NORTHWEST. BEST LIFT WILL RUN FROM
SOUTHWEST TO NORTHEAST ALONG BOUNDARY AS IT SHIFTS FARTHER SOUTH
THROUGH THE DAY. THEREFORE THE GREATEST POPS WILL BE IN THE
MORNING...FAIRLY WIDESPREAD ACROSS MUCH OF THE AREA AND THEN
DIMINISHING THROUGH THE AFTERNOON AS DIGGING MID TO UPPER TROUGH
AND HIGH PRESSURE PUSH FRONT SOUTHWARD. EXPECT A COOL RAIN AS
TEMPS DROP FROM MID 40S IN THE MORNING DOWN TO 30S BY AFTN. LATEST
SOUNDINGS KEEP SATURATED COLUMN ABOVE FREEZING UNTIL MON AFTN INTO
EARLY EVE. ONCE COLUMN GOES BELOW FREEZING IT DRIES OUT...LEAVING
ONLY A THIN SATURATED LAYER BETWEEN 6 TO 7 K FT AFTER 00Z ON NAM
SOUNDING. THEREFORE WILL FOLLOW PREVIOUS FORECAST KEEPING POPS OUT
OF FORECAST ONCE FZN PCP IS POSSIBLE LATE MONDAY.
COASTAL CAROLINAS WILL REMAIN AT THE BASE OF A VERY BROAD UPPER
TROUGH THROUGH REMAINDER OF THE PERIOD AS COOL SFC HIGH EXTENDS
DOWN FROM THE NORTH. FRONT WILL LINGER FROM SW TO NE SOUTH OF
FORECAST AREA WITH COOL AIR LOCKED IN PLACE MON NIGHT THROUGH
TUES. TEMPS MONDAY NIGHT WILL FALL INTO THE 20S IN PLENTY OF CAA.
TEMPS AT H85 DROP FROM AROUND 7 C MON MORNING DOWN TO -3C BY TUES
MORNING. MODELS CONTINUE TO SHOW A PERTURBATION MOVING ACROSS THE
CAROLINAS WITH ANOTHER WAVE OF LOW PRESSURE RIDING ALONG THE
FRONT OVERNIGHT MONDAY INTO TUES AS THE FRONT STARTS LIFTING NORTH.
NAM IS MOST AGGRESSIVE IN BRINGING MOISTURE AND LIFT NORTH EARLY
IN THE DAY ON TUES. FOR NOW HAVE INCLUDED SLIGHT CHC UP THROUGH
PORTIONS OF FLORENCE ACROSS TO THE GRAND STRAND AND SOUTH
INITIALLY AND SPREAD NORTH REMAINING ALIGNED MORE ALONG THE COAST
LATER ON TUES. HAVE INCLUDED SOME MIXED PCP AS SOUNDINGS REMAIN
BELOW ZERO UP THROUGH THE COLUMN MON NIGHT INTO EARLY TUES WITH A
WARM NOSE DEVELOPING INTO THE DAY BUT COLD TEMPS HOLDING ON. AS
FRONT TRIES TO MOVE NORTH EXPECT PCP TO SPREAD FARTHER NORTH ON
TUES. SHOULD GET PUSHED SOUTH AND EAST AS ANOTHER FRONT MOVES IN
FROM THE WEST BY WED MORNING. TEMPS SHOULD REMAIN COOL THROUGH THE
PERIOD.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...LARGE...BUT NOT EXCEPTIONALLY DEEP...TROUGH
WILL PERSIST ACROSS THE EAST INTO THE UPCOMING WEEKEND MAINTAIN
COLD AND UNSETTLED CONDITIONS FOR MUCH OF THE EXTENDED.
COLD FRONT STALLED WELL SOUTH OF THE AREA WILL SERVE AS THE
BAROCLINIC GRADIENT ALONG WHICH AN ACTIVE SOUTHERN STREAM WILL SPAWN
SEVERAL WAVES OF LOW PRESSURE. WHILE NONE OF THESE WILL BE
IMPRESSIVELY STRONG...EACH ONE WILL BRING AT LEAST A CHANCE OF
PRECIP TO THE AREA. TWO QUESTIONS WILL SURROUND EACH PASSING WAVE OF
LOW PRESSURE HOWEVER...HOW MUCH PRECIP WILL EXTEND NORTH FROM THE
LOW...AND WHETHER COLD ENOUGH AIR WILL BE IN PLACE FOR MIXED P-TYPE.
THE FIRST OF THESE...WEDNESDAY NIGHT AND THURSDAY...LOOKS NOW TO BE
THE MOST SIGNIFICANT OF THE WEEK. GUIDANCE IS TRACKING THIS SURFACE
LOW A LITTLE FURTHER WEST THAN PREVIOUS RUNS...AND THUS SLINGING
MORE PRECIP INTO THE CAROLINAS. ADMITTEDLY...THE E-W ORIENTED
BAROCLINIC ZONE DOES NOT`T SUPPORT A VERY FAR WEST TRACK AND WILL LEAN
MORE ON THE DRIER GFS...BUT WIDESPREAD CLOUDS WITH PERIODS OF PRECIP
ARE POSSIBLE WEDNESDAY NIGHT INTO THURSDAY. WITH COLD HIGH PRESSURE
IN PLACE RAIN COULD MIX WITH SOME FREEZING/FROZEN PRECIP...EVEN
THOUGH RAIN IS EXPECTED TO BE THE PRIMARY P-TYPE. THE ECMWF...WHICH
IS MORE ROBUST WITH ITS PRECIP...IS ALSO COLDER...BUT EVEN THE GFS
DEPICTS A PERIOD OF MIXED PRECIP. LOCAL TOP-DOWN METHODOLOGY
PRODUCES PRIMARILY RAIN AS EXPECTED...BUT HAVE LEFT A PERIOD OF MIX
PRECIP...RAIN AND SNOW WITH SNOW ONLY FAR NW...LATE WED NIGHT. QPF
WILL BE LIGHT AND POP IS LOW...BUT SNOWFLAKES ARE POSSIBLE WED NIGHT
BEFORE TEMPS WARM TO SUPPORT ONLY RAIN DURING THURSDAY.
A PERIOD OF DRIER WEATHER IS EXPECTED LATE THURSDAY INTO
FRIDAY...BEFORE ANOTHER LOW PRESSURE MOVES ALONG THE STALLED
BOUNDARY TO THE SOUTH. HOWEVER...EVEN DURING THIS "DRIER" PERIOD A
SCHC POP REMAINS WARRANTED DUE TO WAVES OF LOW PRESSURE ALONG THE
OFFSHORE BAROCLINIC GRADIENT - AND THERE IS LOW CONFIDENCE IN THE
TIMING/TRACK OF THESE FEATURES. THE PAST FEW DAYS...ECMWF/GFS HAD
SHOWN GOOD AGREEMENT IN BRINGING MORE SIGNIFICANT PRECIP LOCALLY
FRIDAY INTO SATURDAY...MUCH OF WHICH WOULD BE OF THE
FREEZING-TO-LIQUID TRANSITION VARIETY. TODAY...GUIDANCE HAS BACKED
OFF CONSIDERABLY...WHICH MAY MAKE SENSE DUE TO THE EXPECTED QUICK
E/NE TRACK OF SURFACE FEATURES. STILL...AM INCLINED TO MAKE ONLY
MINIMAL CHANGES TO THE FRI/SAT TIMEFRAME AS THIS REPRESENTS A NEW
SOLUTION...AND WILL LEAVE LOW MENTIONABLE POP WITH MIXED P-TYPE.
BY SUNDAY THE LONGWAVE TROUGH WILL BEGIN TO
ERODE...FINALLY...BRINGING BRIGHTER WEATHER AND MORE SEASONABLE
TEMPERATURES AFTER THE FIRST 4 DAYS OF THE EXTENDED CONTINUE WELL
BELOW NORMAL.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...EXPECT PCPN IN THE FORM OF LIGHT RAIN TO STREAM ACROSS
THE FORECAST AREA BOTH ALONG AND BEHIND THE COLD FRONTAL
BOUNDARY. MOISTURE WILL CONTINUE TO FEED ALONG THE FRONT AS
ASSOCIATED UPPER LEVEL DISTURBANCE RIDES ALONG THE FRONT AND WILL
ENHANCE THE RAINFALL DURING THE PRE-DAWN MON HOURS INTO DAYTIME
MON MORNING. IFR AND POSSIBLY LIFR FROM BOTH CEILINGS AND VSBY
FROM BR AND FG WILL LIKELY DOMINATE ALL TERMINALS THROUGH THE PRE-
DAWN MON HOURS...WITH A SLOW IMPROVEMENT DURING DAYTIME MON
MORNING INTO THE AFTERNOON AS THE FRONT DROPS FURTHER
SOUTH...ENDING THE THREAT FOR PCPN WITH BOTH VSBY AND CEILINGS
IMPROVING. IMMEDIATELY AFTER THE CFP...WINDS WILL VEER TO 360-020
AT 5 TO 10 KT...INCREASING DURING MONDAY TO 10 TO 20 KT...WITH
SOME GUSTS IN THE 20S ESPECIALLY ACROSS THE COASTAL TERMS. THIS IN
RESPONSE TO THE COMBINED EFFORTS OF COLD AIR ADVECTION AND A
TIGHTENED SFC PRESSURE GRADIENT.
EXTENDED OUTLOOK...WAVES OF LOW PRESSURE TO AFFECT THE LOCAL AREA
DURING THE EXTENDED PERIOD...RESULTING WITH POSSIBLE LIFR/IFR/MVFR
CONDITIONS.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM SUNDAY...WINDS ARE RELATIVELY LIGHT OVER THE WATERS
WITH SEAS RANGING FROM 2 TO 4 FEET. FRYING PAN SHOALS IS NOW
REPORTING SEAS DOWN TO 5 FEET JUST OUTSIDE THE COASTAL WATERS. A
LIGHT RAIN IS EXPECTED OVERNIGHT AS A COLD FRONT SLOWLY
APPROACHES THE WATERS BY DAYBREAK.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 330 PM SUNDAY...SMALL CRAFT ISSUED FOR MONDAY THROUGH EARLY
TUES AS ARCTIC HIGH PRESSURE BUILDS DOWN BEHIND COLD FRONT. THIS
COLD FRONT WILL LINGER SOUTH OF AREA KEEPING TIGHTENED GRADIENT
FLOW THROUGH MON NIGHT AND ALONG WITH PLENTY OF CAA...WINDS AND
SEAS WILL RAMP UP TO 5 TO 7 FT IN STRONG NORTHERLY FLOW UP AROUND
25 KTS IN OUTER WATERS. THE STRONG N TO OFF SHORE COMPONENT WILL
KEEP HIGHEST SEAS AWAY FROM SHORE. WINDS START DECREASING TUE AS
ELONGATED SURFACE RIDGE AXIS MOVES TO THE COAST AND GRADIENT
RELAXES. LIGHT WINDS LATE TUE CONTINUE TUE NIGHT AS THE WEAK HIGH
EXITS NORTHEAST AND WINDS BACK TO WEST-SOUTHWEST. SEAS FALL TO 3
TO 5 FT LATER TUE AND 2 TO 4 FT TUE NIGHT.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...DIFFUSE PRESSURE PATTERN WEDNESDAY LEAVES A
WEAK GRADIENT AND LIGHT W-NW WINDS ACROSS THE WATERS. THIS WILL
CHANGE RAPIDLY WEDNESDAY NIGHT AND INTO THURSDAY AS A LOW PRESSURE
SYSTEM MOVES SE OF THE WATERS. THE LOW TRACK WILL REMAIN OUTSIDE THE
COASTAL WATERS...BUT THE GRADIENT AROUND THIS LOW WILL CAUSE NE
WINDS TO INCREASE STEADILY...BECOMING 15-20 KTS EARLY THURSDAY. AS
THE LOW PULLS AWAY THURSDAY NIGHT...THE GRADIENT WILL REMAIN PINCHED
THANKS TO A STALLED COLD FRONT SOUTH OF THE AREA...ALONG WHICH
ANOTHER LOW PRESSURE WILL DEVELOP AND MOVE OFF THE COAST FRIDAY.
THIS CONTINUES THE NE WINDS AT 15-20 KTS THROUGH THE END OF THE
PERIOD. SEAS WEDNESDAY WILL BE JUST 1-3 FT ON THE LIGHT AND VARIABLE
WINDS...BUT WILL INCREASE QUICKLY WED NIGHT ON THE INCREASING NE
FETCH. WAVE HEIGHTS BUILD TO 4-6 FT THURSDAY MORNING...AND THEN EVEN
A LITTLE HIGHER ON FRIDAY...AND AN EXTENDED SMALL CRAFT ADVISORY
WILL LIKELY BE NEEDED FOR MOST OF THURSDAY AND FRIDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 2 PM EST
TUESDAY FOR AMZ250-252-254-256.
&&
$$
SYNOPSIS...RGZ
NEAR TERM...DRH
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...DCH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
850 PM CST TUE FEB 24 2015
.UPDATE...
ISSUED AT 850 PM CST TUE FEB 24 2015
LATEST RADAR IS NOT VERY IMPRESSIVE COMPARED TO WHERE WE HAD OUR
GREATEST SNOW AMOUNTS. HEAVIEST PRECIPITATION THIS EVENING HAS
BEEN ASSOCIATED WITH THE SURFACE LOW AND INVERTED TROUGH OVER
EASTERN MONTANA. LATEST ITERATIONS OF THE RAP/HRRR KEEP THIS
PRECIPITATION CONFINED TO MAINLY SOUTHWEST AND FAR SOUTH CENTRAL
NORTH DAKOTA...PERHAPS SLIDING EAST OF THE MISSOURI RIVER OVER THE
FAR SOUTH CENTRAL...THROUGH AROUND 08-09 UTC. THEREAFTER QPF IS
VERY LIGHT IN NATURE ALONG THE BAROCLINIC ZONE OVER CENTRAL NORTH
DAKOTA. NOT MUCH CURRENTLY HAPPENING FROM THE NORTHWEST INTO THE
SOUTH CENTRAL PRESENTLY. LATEST RAP SOUNDINGS DO SUGGEST A DRY
LAYER ALOFT AND HAVE ADDED A MENTION OF PATCHY FREEZING DRIZZLE
THROUGH THE REMAINDER OF THIS EVENING. THIS SHOULD DISSIPATE AFTER
MIDNIGHT AS MOISTURE ALOFT INCREASES.
WE DID GET SOME SNOW DURING THE DAY WITH AROUND AN 1.5 INCHES
REPORTED AT WILLISTON. HOWEVER MOST OF WHAT FELL DURING THE DAY
MELTED DUE TO OUR WARM TEMPERATURES. LATEST NAM/RAP/HRRR INDICATE
PRECIPITATION TAPERING QUICKLY FROM NORTH TO SOUTH WEDNESDAY WITH
PRECIPITATION MOSTLY ENDED BY MIDDAY...EXCEPT PERHAPS ALONG THE
SOUTH DAKOTA BORDER. THEREFORE HAVE ADJUSTED SNOW AMOUNTS AND HAVE
NOT INCLUDED WHAT FELL DURING THE DAY. WITH THIS...WE ARE NOW
LOOKING AT SNOW TOTALS TONIGHT THROUGH EARLY AFTERNOON WEDNESDAY
OF MAINLY AN INCH OR LESS. WITH HIGHER AMOUNTS...UP TO 2 INCHES
OVER THE FAR SOUTH CENTRAL FROM SIOUX...SOUTHERN GRANT AND
SOUTHERN MORTON COUNTIES...EAST THROUGH SOUTHERN EMMONS AND INTO
DICKEY AND MCINTOSH COUNTIES. LESSER AMOUNTS ARE NOTED OVER THE
TURTLE MOUNTAINS INTO THE NORTHERN JAMES RIVER VALLEY...AND OVER
THE FAR SOUTHWEST.
UPDATE ISSUED AT 606 PM CST TUE FEB 24 2015
FRONTAL BOUNDARY REMAINS OVER NORTHEAST MONTANA INTO FAR SOUTHWEST
NORTH DAKOTA. CURRENT RADAR IMAGERY SHOWS SOME HIGHER
REFLECTIVITIES FROM WEST CENTRAL INTO SOUTHWEST NORTH DAKOTA. A
FEW LIGHTER REFLECTIVITIES WERE LOCATED OVER THE NORTH CENTRAL. IN
GENERAL THOUGH...A DECREASE OVER THE PAST FEW HOURS. HAVE ADJUSTED
POPS DOWN EARLY THIS EVENING FOR MANY AREAS. THINK SNOW WILL PICK
UP AGAIN LATER TONIGHT INTO THE OVERNIGHT HOURS AS THE SURFACE LOW
SLIDES ALONG THE FRONTAL ZONE AND PUSHES THE INVERTED SURFACE
TROUGH INTO SOUTHWEST NORTH DAKOTA. THIS WILL ENHANCE THE
BAROCLINIC ZONE OVER WESTERN AND CENTRAL NORTH DAKOTA. OTHERWISE
NO BIG CHANGES EARLY THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 300 PM CST TUE FEB 24 2015
CURRENT SURFACE ANALYSIS PLACES PRIMARY LOW TO THE SOUTH OF JAMES
BAY WHILE SECONDARY LOW CONTINUES TO DEEPEN AND SLIDE SOUTH FROM
SOUTHWEST SASKATCHEWAN INTO NORTHEAST MONTANA. COLD FRONT CONTINUES
TO WORK SOUTH STRETCHING FROM EAST-CENTRAL SOUTH DAKOTA INTO FAR
SOUTHWEST NORTH DAKOTA. BEHIND THE FRONT...TEMPERATURES CONTINUE
TO EITHER HOLD STEADY OR SLOWLY DROP. UPPER LEVEL ANALYSIS PLACES
LOW OVER NORTHERN ONTARIO WITH SECONDARY LOW SLIDING FROM EASTERN
ARIZONA INTO NEW MEXICO...WHILE RIDGE REMAINS OFF THE PACIFIC
COAST. ACTIVE NORTHWEST FLOW REMAINS OVER OUR AREA. INITIAL ROUND
OF SNOW CONTINUES OVER PORTIONS OF THE AREA AFFILIATED WITH RIGHT
ENTRANCE REGION OF PASSING JET STREAK AND MODEST ISENTROPIC LIFT.
FOR THE REST OF THIS AFTERNOON INTO TONIGHT...AFOREMENTIONED JET
STREAK WILL CONTINUE TO PROGRESS OFF TO THE SOUTHEAST AND
ISENTROPIC LIFT STARTS TO WEAKEN WHICH MAY BRING A BRIEF BREAK IN
THE SNOW...THOUGH EXPECT ANOTHER ROUND OF ENHANCED SNOWFALL TONIGHT
AS SHORT WAVE OVER CENTRAL SASKATCHEWAN MAKES ITS APPROACH INTO
THE REGION. LATEST SUITE OF MODELS HAS DONE A BIT OF A SHIFT TO
THE EAST WHEN COMPARED TO PREVIOUS RUNS...SO HAVE PUSHED THE FOCUS
FOR HIGHER POPS AND SNOW AMOUNTS FURTHER TOWARDS CENTRAL NORTH
DAKOTA. COLD AIRMASS WILL CONTINUE ITS SHIFT INTO THE AREA WITH
LOWS MAINLY IN THE SINGLE DIGITS...AND BELOW ZERO READINGS OVER
PARTS OF NORTH CENTRAL.
ON WEDNESDAY...SNOW WILL SLOWLY SHIFT OFF TO THE SOUTH THROUGH THE
DAY WITH THE PROGRESSION WITH THE AFOREMENTIONED UPPER WAVE. COLD
AIRMASS WILL CONTINUE TO POUR INTO THE AREA BRINGING HIGH
TEMPERATURES CLOSE TO THE PREVIOUS NIGHTS LOWS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 PM CST TUE FEB 24 2015
THE EXTENDED CONTINUES TO BE DOMINATED BY A BLOCKING RIDGE OVER
THE EASTERN PACIFIC AND THE RESULTING DOWNSTREAM COLD UPPER LOW
FROM CENTRAL AND EASTERN CANADA THOUGH THE SOUTHWEST US. THIS WILL
KEEP THE EXTENDED PERIOD COLD AND DRY.
WEDNESDAY NIGHT THROUGH FRIDAY: A 1044MB ARCTIC HIGH PRESSURE CENTER
OVER SOUTHERN SASKATCHEWAN WEDNESDAY EVENING WILL PUSH SOUTHEAST
TOWARDS THE NORTH DAKOTA BORDER. THE MODELS PLACE THE HIGH CENTER
OVER CENTRAL NORTH DAKOTA BY THURSDAY AFTERNOON/EVENING...AND INTO
EASTERN SOUTH DAKOTA BY DAYBREAK FRIDAY MORNING. LOWS WEDNESDAY
NIGHT AND THURSDAY NIGHT SHOULD RANGE FROM 5 BELOW TO 20 BELOW
ZERO...WITH HIGHS ON THURSDAY FROM ZERO TO 10 ABOVE. WIND CHILLS
WILL BE THE MAIN CONCERN DURING THIS PERIOD. WIND CHILLS 25 TO 40
BELOW WILL BE A HAZARD WEDNESDAY NIGHT INTO THURSDAY MORNING AND
AGAIN THURSDAY NIGHT INTO FRIDAY MORNING OVER MOST OF THE
REGION...WITH THE FAR SOUTHWEST ESCAPING THE COLDEST WIND CHILL
VALUES.
THE WEEKEND INTO MONDAY WILL BE COOL AND DRY AS THE PRECIPITATION
WILL BE LIMITED TO THE BAROCLINIC ZONES SURROUNDING THE NORTHERN
PLAINS LEAVING NORTH DAKOTA DRY. HIGHS SHOULD BE MAINLY IN THE TEENS
AND 20S...WITH LOWS FROM 5 BELOW TO 10 ABOVE ZERO OVER MUCH OF THE
AREA THIS WEEKEND. A SLIGHT MODERATION IS POSSIBLE MONDAY WITH HIGHS
IN THE 20S TO LOWER 30S...BUT THEN COOLER AGAIN FOR TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 850 PM CST TUE FEB 24 2015
MVFR TO IFR CONDITIONS EXPECTED AT KDIK TONIGHT AND WEDNESDAY
MORNING IN PERIODS OF LIGHT SNOW AND FOG. MAINLY MVFR CONDITIONS
AT KBIS AND KISN TONIGHT AND WEDNESDAY MORNING IN LIGHT SNOW. KMOT
AND KJMS ARE EXPECTED TO REMAIN MAINLY VFR BUT WITH PERIODS OF
MVFR CEILINGS/VISIBILITIES IN LIGHT SNOW TONIGHT. EASTERLY FLOW
WILL SHIFT NORTHEAST AND THEN NORTH WEDNESDAY WITH WINDS
INCREASING FROM AROUND 10 KNOTS TONIGHT TO 10 TO 20 KNOTS WEDNESDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...JJS
LONG TERM...JV
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS TULSA OK
1112 AM CST MON FEB 23 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
FOR THE 18Z TAFS... INTERMITTENT SNOW SHOWERS WILL CONTINUE TO AFFECT
ALL SITES THIS AFTERNOON... CREATING TEMPORARY MVFR CONDITIONS. A
BRIEF PERIOD OF IFR CONDITIONS MAY BE A POSSIBILITY WITH ANY AREAS
OF HEAVIER PRECIPITATION THAT HAPPEN TO PASS OVER A TERMINAL SITE.
PRECIPITATION WILL END FROM WEST TO EAST LATE THIS AFTERNOON. WHILE
CONDITIONS SLOWLY IMPROVE ACROSS EASTERN OKLAHOMA... MVFR CEILINGS
ARE EXPECTED TO PREVAIL THROUGHOUT THE FORECAST PERIOD AT ARKANSAS
SITES.
&&
.PREV DISCUSSION... /ISSUED 1056 AM CST MON FEB 23 2015/
..UPDATE...
DISCUSSION...
THE HEAVIEST PRECIPITATION CONTINUES TO WORK ITS WAY EAST ACROSS
THE FORECAST AREA AND IS ENTERING WEST CENTRAL ARKANSAS. AREAS ALONG
AND SOUTH OF INTERSTATE 40 WILL SEE THE BULK OF ACTIVITY FOR THE
REMAINDER OF THE DAY. SCATTERED AREAS OF LIGHT PRECIPITATION
CONTINUE TO DEVELOP WEST OF THE FORECAST AREA WHICH WILL CONTINUE
TO PRODUCE INTERMITTENT ACTIVITY ACROSS MUCH OF THE REMAINDER OF
OUR AREA. AS SUCH... HAVE NOT CHANGED POPS OR FORECAST
TEMPERATURES FOR THIS AFTERNOON.
PREV DISCUSSION... /ISSUED 539 AM CST MON FEB 23 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
WIDESPREAD LIGHT SNOW WILL TRACK ACROSS NE OK / FAR NW AR WITH
MINIMAL FLIGHT IMPACTS EXPECTED. MORE WIDESPREAD AND PROLONGED
AVIATION IMPACTS ARE EXPECTED ACROSS SE OK INTO WEST CENTRAL
ARKANSAS W/ MVFR TO IFR CONDITIONS LIKELY. PRECIP WILL DIMINISH BY
EARLY EVENING WITH A TREND TOWARD VFR / MVFR CEILINGS.
PREV DISCUSSION... /ISSUED 406 AM CST MON FEB 23 2015/
DISCUSSION...
ANOTHER ROUND OF WINTER WEATHER IS ABOUT TO GET UNDERWAY ACROSS
PARTS OF EASTERN OK EARLY THIS MORNING. A LARGE AREA OF SHOWERY
PRECIP HAS SPREAD ACROSS WESTERN/CENTRAL OK A LITTLE AHEAD OF
SCHEDULE...WITH SEVERAL REPORTS OF GRAUPEL OR ICE PELLETS DESPITE
ALL MODEL SOUNDINGS POINTING TO SNOW. STILL BELIEVE THIS WILL
MAINLY BE A SNOW EVENT FOR ALL BUT FAR SOUTHERN OK BUT THE
CONVECTIVE NATURE OF AT LEAST THIS EARLY ROUND OF PRECIP LENDS SOME
CONFIDENCE TO ADDING A SLEET/SNOW MIXTURE NORTH TO ABOUT I-40 THIS
MORNING. OVERALL CONFIGURATION AND TIMING OF ADVISORY APPEARS GOOD
FOR NOW...THOUGH MUCH OF THE EVENT MAY BE DONE WELL BEFORE 00Z
EXPIRATION TIME. LATEST RUNS OF HRRR HAVE ALSO SPREAD HEAVIER SNOW
TOTALS A BIT FARTHER NORTH ACROSS EASTERN OK AND THIS WILL NEED TO
BE WATCHED THROUGHOUT THE DAY. TEMPS TODAY WILL NOT GO MUCH OF
ANYWHERE WITH MOSTLY LOW/MID 20S FOR HIGHS.
COLD AND DRY TONIGHT WITH A MODEST WARM UP ON TUESDAY...WHICH WILL
FEEL NICE AFTER LAST COUPLE OF DAYS DESPITE BEING SEVERAL DEGREES
BELOW NORMAL. UPPER LEVEL SYSTEM OVER THE SOUTHWEST WILL MOVE EAST
ACROSS TEXAS TUE NIGHT INTO WED...WITH A SMALL CHANCE OF PRECIP
SPREADING INTO SE OKLAHOMA DURING THAT TIME IN THE FORM OF LIGHT
SNOW OR SLEET. THIS IS NOT EXPECTED TO BE MUCH OF AN ISSUE AS THE
HEAVIER PRECIP SHOULD STAY SOUTH OF THE RED RIVER. A NICE WARM UP
FOR WEDNESDAY BUT NOT FOR LONG AS ANOTHER SURGE OF MUCH COLDER AIR
PLUNGES SOUTH BY THURSDAY.
HIGH LEVELS OF UNCERTAINTY IN THE EXTENDED FORECAST BUT IT DOES
APPEAR THAT TEMPS WILL WARM UP BY NEXT WEEKEND...ENOUGH FOR ANY
PRECIP TO BE LIQUID. THERE STILL MAY BE A TRANSITION PERIOD LATE
IN THE WEEK HOWEVER SO WINTER WEATHER POTENTIAL WILL STILL BE
PRESENT FOR THU INTO SAT. FORECAST CONFIDENCE REMAINS QUITE LOW
BEYOND THURSDAY.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR OKZ049-OKZ053-
OKZ065-OKZ066-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-
OKZ076.
AR...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR ARZ019-ARZ020-
ARZ029.
&&
$$
AVIATION...06
AREA FORECAST DISCUSSION
NWS TULSA OK
1056 AM CST MON FEB 23 2015
...UPDATE...
.DISCUSSION...
THE HEAVIEST PRECIPITATION CONTINUES TO WORK ITS WAY EAST ACROSS
THE FORECAST AREA AND IS ENTERING WEST CENTRAL ARKANSAS. AREAS ALONG
AND SOUTH OF INTERSTATE 40 WILL SEE THE BULK OF ACTIVITY FOR THE
REMAINDER OF THE DAY. SCATTERED AREAS OF LIGHT PRECIPITATION
CONTINUE TO DEVELOP WEST OF THE FORECAST AREA WHICH WILL CONTINUE
TO PRODUCE INTERMITTENT ACTIVITY ACROSS MUCH OF THE REMAINDER OF
OUR AREA. AS SUCH... HAVE NOT CHANGED POPS OR FORECAST
TEMPERATURES FOR THIS AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 539 AM CST MON FEB 23 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
WIDESPREAD LIGHT SNOW WILL TRACK ACROSS NE OK / FAR NW AR WITH
MINIMAL FLIGHT IMPACTS EXPECTED. MORE WIDESPREAD AND PROLONGED
AVIATION IMPACTS ARE EXPECTED ACROSS SE OK INTO WEST CENTRAL
ARKANSAS W/ MVFR TO IFR CONDITIONS LIKELY. PRECIP WILL DIMINISH BY
EARLY EVENING WITH A TREND TOWARD VFR / MVFR CEILINGS.
PREV DISCUSSION... /ISSUED 406 AM CST MON FEB 23 2015/
DISCUSSION...
ANOTHER ROUND OF WINTER WEATHER IS ABOUT TO GET UNDERWAY ACROSS
PARTS OF EASTERN OK EARLY THIS MORNING. A LARGE AREA OF SHOWERY
PRECIP HAS SPREAD ACROSS WESTERN/CENTRAL OK A LITTLE AHEAD OF
SCHEDULE...WITH SEVERAL REPORTS OF GRAUPEL OR ICE PELLETS DESPITE
ALL MODEL SOUNDINGS POINTING TO SNOW. STILL BELIEVE THIS WILL
MAINLY BE A SNOW EVENT FOR ALL BUT FAR SOUTHERN OK BUT THE
CONVECTIVE NATURE OF AT LEAST THIS EARLY ROUND OF PRECIP LENDS SOME
CONFIDENCE TO ADDING A SLEET/SNOW MIXTURE NORTH TO ABOUT I-40 THIS
MORNING. OVERALL CONFIGURATION AND TIMING OF ADVISORY APPEARS GOOD
FOR NOW...THOUGH MUCH OF THE EVENT MAY BE DONE WELL BEFORE 00Z
EXPIRATION TIME. LATEST RUNS OF HRRR HAVE ALSO SPREAD HEAVIER SNOW
TOTALS A BIT FARTHER NORTH ACROSS EASTERN OK AND THIS WILL NEED TO
BE WATCHED THROUGHOUT THE DAY. TEMPS TODAY WILL NOT GO MUCH OF
ANYWHERE WITH MOSTLY LOW/MID 20S FOR HIGHS.
COLD AND DRY TONIGHT WITH A MODEST WARM UP ON TUESDAY...WHICH WILL
FEEL NICE AFTER LAST COUPLE OF DAYS DESPITE BEING SEVERAL DEGREES
BELOW NORMAL. UPPER LEVEL SYSTEM OVER THE SOUTHWEST WILL MOVE EAST
ACROSS TEXAS TUE NIGHT INTO WED...WITH A SMALL CHANCE OF PRECIP
SPREADING INTO SE OKLAHOMA DURING THAT TIME IN THE FORM OF LIGHT
SNOW OR SLEET. THIS IS NOT EXPECTED TO BE MUCH OF AN ISSUE AS THE
HEAVIER PRECIP SHOULD STAY SOUTH OF THE RED RIVER. A NICE WARM UP
FOR WEDNESDAY BUT NOT FOR LONG AS ANOTHER SURGE OF MUCH COLDER AIR
PLUNGES SOUTH BY THURSDAY.
HIGH LEVELS OF UNCERTAINTY IN THE EXTENDED FORECAST BUT IT DOES
APPEAR THAT TEMPS WILL WARM UP BY NEXT WEEKEND...ENOUGH FOR ANY
PRECIP TO BE LIQUID. THERE STILL MAY BE A TRANSITION PERIOD LATE
IN THE WEEK HOWEVER SO WINTER WEATHER POTENTIAL WILL STILL BE
PRESENT FOR THU INTO SAT. FORECAST CONFIDENCE REMAINS QUITE LOW
BEYOND THURSDAY.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR OKZ049-OKZ053-
OKZ065-OKZ066-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-
OKZ076.
AR...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR ARZ019-ARZ020-
ARZ029.
&&
$$
SHORT TERM...06
AREA FORECAST DISCUSSION
NWS TULSA OK
539 AM CST MON FEB 23 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
WIDESPREAD LIGHT SNOW WILL TRACK ACROSS NE OK / FAR NW AR WITH
MINIMAL FLIGHT IMPACTS EXPECTED. MORE WIDESPREAD AND PROLONGED
AVIATION IMPACTS ARE EXPECTED ACROSS SE OK INTO WEST CENTRAL
ARKANSAS W/ MVFR TO IFR CONDITIONS LIKELY. PRECIP WILL DIMINISH BY
EARLY EVENING WITH A TREND TOWARD VFR / MVFR CEILINGS.
&&
.PREV DISCUSSION... /ISSUED 406 AM CST MON FEB 23 2015/
DISCUSSION...
ANOTHER ROUND OF WINTER WEATHER IS ABOUT TO GET UNDERWAY ACROSS
PARTS OF EASTERN OK EARLY THIS MORNING. A LARGE AREA OF SHOWERY
PRECIP HAS SPREAD ACROSS WESTERN/CENTRAL OK A LITTLE AHEAD OF
SCHEDULE...WITH SEVERAL REPORTS OF GRAUPEL OR ICE PELLETS DESPITE
ALL MODEL SOUNDINGS POINTING TO SNOW. STILL BELIEVE THIS WILL
MAINLY BE A SNOW EVENT FOR ALL BUT FAR SOUTHERN OK BUT THE
CONVECTIVE NATURE OF AT LEAST THIS EARLY ROUND OF PRECIP LENDS SOME
CONFIDENCE TO ADDING A SLEET/SNOW MIXTURE NORTH TO ABOUT I-40 THIS
MORNING. OVERALL CONFIGURATION AND TIMING OF ADVISORY APPEARS GOOD
FOR NOW...THOUGH MUCH OF THE EVENT MAY BE DONE WELL BEFORE 00Z
EXPIRATION TIME. LATEST RUNS OF HRRR HAVE ALSO SPREAD HEAVIER SNOW
TOTALS A BIT FARTHER NORTH ACROSS EASTERN OK AND THIS WILL NEED TO
BE WATCHED THROUGHOUT THE DAY. TEMPS TODAY WILL NOT GO MUCH OF
ANYWHERE WITH MOSTLY LOW/MID 20S FOR HIGHS.
COLD AND DRY TONIGHT WITH A MODEST WARM UP ON TUESDAY...WHICH WILL
FEEL NICE AFTER LAST COUPLE OF DAYS DESPITE BEING SEVERAL DEGREES
BELOW NORMAL. UPPER LEVEL SYSTEM OVER THE SOUTHWEST WILL MOVE EAST
ACROSS TEXAS TUE NIGHT INTO WED...WITH A SMALL CHANCE OF PRECIP
SPREADING INTO SE OKLAHOMA DURING THAT TIME IN THE FORM OF LIGHT
SNOW OR SLEET. THIS IS NOT EXPECTED TO BE MUCH OF AN ISSUE AS THE
HEAVIER PRECIP SHOULD STAY SOUTH OF THE RED RIVER. A NICE WARM UP
FOR WEDNESDAY BUT NOT FOR LONG AS ANOTHER SURGE OF MUCH COLDER AIR
PLUNGES SOUTH BY THURSDAY.
HIGH LEVELS OF UNCERTAINTY IN THE EXTENDED FORECAST BUT IT DOES
APPEAR THAT TEMPS WILL WARM UP BY NEXT WEEKEND...ENOUGH FOR ANY
PRECIP TO BE LIQUID. THERE STILL MAY BE A TRANSITION PERIOD LATE
IN THE WEEK HOWEVER SO WINTER WEATHER POTENTIAL WILL STILL BE
PRESENT FOR THU INTO SAT. FORECAST CONFIDENCE REMAINS QUITE LOW
BEYOND THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 25 17 43 25 / 30 10 10 10
FSM 29 23 42 26 / 60 20 10 10
MLC 27 17 40 26 / 70 20 10 10
BVO 24 14 44 20 / 20 10 10 10
FYV 24 17 40 21 / 30 10 10 10
BYV 23 18 39 24 / 20 10 10 10
MKO 26 20 42 24 / 40 10 10 10
MIO 25 16 40 23 / 20 10 10 10
F10 25 19 42 26 / 60 10 10 10
HHW 29 22 37 28 / 80 20 10 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR OKZ049-OKZ053-
OKZ065-OKZ066-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-
OKZ076.
AR...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR ARZ019-ARZ020-
ARZ029.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION
NWS TULSA OK
406 AM CST MON FEB 23 2015
.DISCUSSION...
ANOTHER ROUND OF WINTER WEATHER IS ABOUT TO GET UNDERWAY ACROSS
PARTS OF EASTERN OK EARLY THIS MORNING. A LARGE AREA OF SHOWERY
PRECIP HAS SPREAD ACROSS WESTERN/CENTRAL OK A LITTLE AHEAD OF
SCHEDULE...WITH SEVERAL REPORTS OF GRAUPEL OR ICE PELLETS DESPITE
ALL MODEL SOUNDINGS POINTING TO SNOW. STILL BELIEVE THIS WILL
MAINLY BE A SNOW EVENT FOR ALL BUT FAR SOUTHERN OK BUT THE
CONVECTIVE NATURE OF AT LEAST THIS EARLY ROUND OF PRECIP LENDS SOME
CONFIDENCE TO ADDING A SLEET/SNOW MIXTURE NORTH TO ABOUT I-40 THIS
MORNING. OVERALL CONFIGURATION AND TIMING OF ADVISORY APPEARS GOOD
FOR NOW...THOUGH MUCH OF THE EVENT MAY BE DONE WELL BEFORE 00Z
EXPIRATION TIME. LATEST RUNS OF HRRR HAVE ALSO SPREAD HEAVIER SNOW
TOTALS A BIT FARTHER NORTH ACROSS EASTERN OK AND THIS WILL NEED TO
BE WATCHED THROUGHOUT THE DAY. TEMPS TODAY WILL NOT GO MUCH OF
ANYWHERE WITH MOSTLY LOW/MID 20S FOR HIGHS.
COLD AND DRY TONIGHT WITH A MODEST WARM UP ON TUESDAY...WHICH WILL
FEEL NICE AFTER LAST COUPLE OF DAYS DESPITE BEING SEVERAL DEGREES
BELOW NORMAL. UPPER LEVEL SYSTEM OVER THE SOUTHWEST WILL MOVE EAST
ACROSS TEXAS TUE NIGHT INTO WED...WITH A SMALL CHANCE OF PRECIP
SPREADING INTO SE OKLAHOMA DURING THAT TIME IN THE FORM OF LIGHT
SNOW OR SLEET. THIS IS NOT EXPECTED TO BE MUCH OF AN ISSUE AS THE
HEAVIER PRECIP SHOULD STAY SOUTH OF THE RED RIVER. A NICE WARM UP
FOR WEDNESDAY BUT NOT FOR LONG AS ANOTHER SURGE OF MUCH COLDER AIR
PLUNGES SOUTH BY THURSDAY.
HIGH LEVELS OF UNCERTAINTY IN THE EXTENDED FORECAST BUT IT DOES
APPEAR THAT TEMPS WILL WARM UP BY NEXT WEEKEND...ENOUGH FOR ANY
PRECIP TO BE LIQUID. THERE STILL MAY BE A TRANSITION PERIOD LATE
IN THE WEEK HOWEVER SO WINTER WEATHER POTENTIAL WILL STILL BE
PRESENT FOR THU INTO SAT. FORECAST CONFIDENCE REMAINS QUITE LOW
BEYOND THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 25 17 43 25 / 30 10 10 10
FSM 29 23 42 26 / 60 20 10 10
MLC 27 17 40 26 / 70 20 10 10
BVO 24 14 44 20 / 20 10 10 10
FYV 24 17 40 21 / 30 10 10 10
BYV 23 18 39 24 / 20 10 10 10
MKO 26 20 42 24 / 40 10 10 10
MIO 25 16 40 23 / 20 10 10 10
F10 25 19 42 26 / 60 10 10 10
HHW 29 22 37 28 / 80 20 10 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR OKZ049-OKZ053-
OKZ065-OKZ066-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-
OKZ076.
AR...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR ARZ019-ARZ020-
ARZ029.
&&
$$
SHORT TERM...07
LONG TERM....14
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1152 AM CST MON FEB 23 2015
.AVIATION...
FREEZING TEMPERATURES WILL REMAIN ALONG AND NORTH OF A KDRT TO
KHDO TO KHYI TO KGYB LINE THIS AFTERNOON INTO THIS EVENING. THE
PORTION EAST OF KHDO SAGS SOUTH TO A KSAT TO KENEDY TO K66R LINE
BY SUNRISE TUESDAY AND THEN MOVES BACK TO NORTH TUESDAY. PATCHY
-DZ PERSISTS THIS AFTERNOON AND SLOWLY SHIFTS INTO EASTERN AREAS
TONIGHT INTO TUESDAY WITH -FZDZ NORTH OF THE FREEZE LINE. HAVE
CONTINUED -FZDZ FOR KAUS THROUGH MIDDAY TUESDAY AND -DZ FOR
KSAT/KSSF THROUGH THIS EVENING. SOME ICING IS POSSIBLE FROM JUST
ABOVE THE GROUND UP TO 4K FEET. OTHERWISE...IFR/MVFR CIGS PREVAIL
THIS AFTERNOON THROUGH TUESDAY. NLY WINDS 12 TO 17 KTS WITH GUSTS
TO 25 KTS PREVAIL THIS AFTERNOON...THEN DECREASE TO LESS THAN 10
KTS TONIGHT...THEN SLOWLY TURN TO NELY ON TUESDAY. EXCEPT...ALONG
THE RIO GRANDE WHERE THE TURN TO NELY AND ELY TAKES PLACE TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 530 AM CST MON FEB 23 2015/
AVIATION UPDATE...FOR 12Z TAF PACKAGE...
CURRENT CONDITIONS WILL LIKELY PERSIST THROUGH ENTIRE TAF PERIOD.
THERE IS SOME CONCERN FOR -FZDZ THIS MORNING FOR KAUS SO INCLUDED
TEMPO GROUP TO HANDLE THAT. OTHERWISE -DZ EXPECTED FOR ALL
TERMINALS TODAY. AS PREVIOUS FORECAST MENTIONED...ICING WILL BE A
CONCERN FOR THE LOWEST 3KFT JUST OFF THE SURFACE DURING TAKEOFF AND
LANDING FOR ALL TERMINALS. OTHERWISE...MVFR/IFR CEILINGS ARE
EXPECTED THROUGHOUT THE DAY AND NIGHT. GUSTY WINDS WILL ALSO
PERSIST THROUGH THE DAY.
PREV DISCUSSION... /ISSUED 457 AM CST MON FEB 23 2015/
SHORT TERM (TODAY THROUGH TUESDAY)...
EARLY MORNING OBSERVATIONS SHOW THE FREEZING LINE ROUGHLY ALONG A
GEORGETOWN TO BOERNE TO COMSTOCK LINE. OBSERVATIONS ALSO SHOW
LIGHT MIXED PRECIPITATION FALLING ACROSS THE HILL COUNTRY WITH
ONLY TRACE AMOUNTS REPORTED SO FAR. OTHERWISE...RADAR ECHOES
GENERALLY ON THE INCREASE EARLY THIS MORNING...ESPECIALLY ACROSS
THE NORTHERN HILL COUNTRY INCLUDING KERR...GILLESPIE...LLANO AND
BURNET COUNTIES. THE LATEST HRRR AND NAM12 MODELS TEND TO FAVOR
THE ABOVE MENTIONED AREAS FOR PRECIPITATION TODAY AND WE HAVE
PLACED THE HIGHEST CHANCE FOR WINTRY PRECIPITATION HERE. WE/LL
NEED TO MONITOR THESE AREAS CAREFULLY AS ICE ACCUMULATIONS COULD
ADD UP QUICKER IF MULTIPLE ROUNDS OF PRECIPITATION DEVELOP.
OTHERWISE...WE STILL EXPECT WINTRY PRECIPITATION IN THE FORM OF
FREEZING RAIN TO OCCUR ACROSS THE SOUTHERN EDWARDS PLATEAU...HILL
COUNTRY AND PORTIONS OF THE INTERSTATE 35 CORRIDOR MAINLY NORTH OF
SAN MARCOS. WE STILL EXPECT ICE ACCUMULATIONS TO REMAIN AT OR
BELOW 1/10 OF AN INCH...WITH THE MAIN IMPACTS BEING ON BRIDGES AND
ELEVATED ROADWAYS. THE WINTER WEATHER ADVISORY WILL REMAIN IN
EFFECT UNTIL 6 PM TODAY.
OTHERWISE...TEMPERATURES WILL EITHER REMAIN STEADY OF SLOWLY FALL
TODAY DUE TO THE COMBINATION OF COLD AIR ADVECTION...CLOUD COVER
AND LIGHT PRECIPITATION. FOR THE EVENING AND OVERNIGHT HOURS...WE
EXPECT A FAIRLY QUICK DECREASE IN PRECIPITATION CHANCES FROM WEST
TO EAST ACROSS THE REGION. WE CONTEMPLATED EXPANDING THE WINTER
WEATHER ADVISORY FARTHER EAST TO COVER AREAS MAINLY NORTH OF
I-10/EAST OF I-35. HOWEVER...THE MODELS HAVE BEEN CONSISTENT IN
SHOWING A RATHER QUICK DECREASE IN THE PRECIPITATION THIS EVENING.
WE/LL CONTINUE TO HIGHLIGHT THIS REGION IN A SPECIAL WEATHER
STATEMENT TO COVER THE COLD TEMPERATURES AND POTENTIAL FOR LIGHT
WINTRY PRECIPITATION. PRECIPITATION CHANCES TEMPORARILY DECREASE
ON TUESDAY AS MID-LEVEL DRYING/WEAK SUBSIDENCE MOVE IN FROM THE
WEST.
LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...
ANOTHER UPPER LEVEL TROUGH APPROACHES SOUTH CENTRAL TEXAS FROM THE
WEST TUESDAY NIGHT. THE LATEST ROUND OF MODEL GUIDANCE IS SHOWING
THIS SYSTEM TO BE A LITTLE STRONGER WHEN COMPARED TO PREVIOUS
RUNS. WE HAVE INCREASED PRECIPITATION CHANCES SLIGHTLY FOR TUESDAY
NIGHT AND WEDNESDAY. AT THIS TIME...TEMPERATURES ARE EXPECTED TO
REMAIN ABOVE FREEZING TUESDAY NIGHT...SO WE/LL KEEP THE
PRECIPITATION AS ALL LIQUID. AS THE ABOVE MENTIONED UPPER LEVEL
STORM SYSTEM DEPARTS THE REGION BY LATE WEDNESDAY... ANOTHER
SYSTEM MOVES THROUGH ON THURSDAY. WE/LL KEEP THE FORECAST DRY AS
MOISTURE WILL BE LACKING. WE DO EXPECT ANOTHER SHOT OF COOLER AIR
TO MOVE THROUGH ON THURSDAY...FOLLOWED BY COOLER TEMPERATURES ON
FRIDAY. WE/LL KEEP A SLIGHT CHANCE FOR LIGHT RAIN IN THE FORECAST
FRIDAY THROUGH SUNDAY AS SOUTHERLY FLOW JUST ABOVE THE COLD
SURFACE AIR BEGINS TO SET UP A WARM AIR ADVECTION PATTERN.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 33 30 43 36 58 / 70 30 20 30 30
AUSTIN BERGSTROM INTL AIRPORT 34 30 43 34 57 / 70 30 20 30 30
NEW BRAUNFELS MUNI AIRPORT 36 30 45 37 61 / 60 30 10 30 20
BURNET MUNI AIRPORT 31 26 41 34 57 / 80 30 20 30 20
DEL RIO INTL AIRPORT 38 34 52 41 68 / 50 10 10 10 -
GEORGETOWN MUNI AIRPORT 33 27 42 34 56 / 70 40 20 30 30
HONDO MUNI AIRPORT 37 32 48 38 65 / 50 20 10 20 -
SAN MARCOS MUNI AIRPORT 35 30 44 37 59 / 70 30 10 30 20
LA GRANGE - FAYETTE REGIONAL 38 31 43 38 57 / 70 40 20 30 30
SAN ANTONIO INTL AIRPORT 38 31 45 38 62 / 60 30 10 20 10
STINSON MUNI AIRPORT 39 32 46 39 63 / 60 30 10 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS...
GILLESPIE...HAYS...KENDALL...KERR...LLANO...REAL...TRAVIS...VAL
VERDE...WILLIAMSON.
&&
$$
MESOSCALE/AVIATION...04
SYNOPTIC/GRIDS...17
PUBLIC SERVICE/DATA COLLECTION...00
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1141 AM CST MON FEB 23 2015
.UPDATE...
LIGHT FREEZING RAIN/DRIZZLE CONTINUE TO AFFECT THE NORTHEAST PART
OF SOUTH CENTRAL TEXAS LATE THIS MORNING. CURRENTLY TEMPERATURES
ARE IN THE UPPER 20S AND LOWER 30S ACROSS THOSE LOCATIONS. AREA RADARS
AND HIRES MODEL SOLUTIONS ARE ENDING PRECIPITATION BY NOON OR 1
PM THIS AFTERNOON ACROSS MOST AREAS. HOWEVER...THERE IS A SLIGHT CHANCE
FOR FREEZING DRIZZLE ACROSS THE NORTHERN PORTION OF THE HILL
COUNTRY...ESPECIALLY...NORTH OF A LLANO TO LAKEWAY TO TAYLOR LINE.
TEMPERATURES WILL REMAIN IN THE UPPER 20S AND LOWER 30S FOR THE
REMAINDER OF THE DAY ACROSS THE HILL COUNTRY AND MID TO UPPER 30S
EAST OF THE I35 CORRIDOR. ICE ACCUMULATIONS ARE NOT
EXPECTED...HOWEVER...A THIN LAYER OF ICING ON THE GROUND...MAY BE
POSSIBLE OVER SOME LOCATIONS AND RESULTING IN MINOR TRAVEL
IMPACTS.
&&
.PREV DISCUSSION... /ISSUED 530 AM CST MON FEB 23 2015/
AVIATION UPDATE...FOR 12Z TAF PACKAGE...
CURRENT CONDITIONS WILL LIKELY PERSIST THROUGH ENTIRE TAF PERIOD.
THERE IS SOME CONCERN FOR -FZDZ THIS MORNING FOR KAUS SO INCLUDED
TEMPO GROUP TO HANDLE THAT. OTHERWISE -DZ EXPECTED FOR ALL
TERMINALS TODAY. AS PREVIOUS FORECAST MENTIONED...ICING WILL BE A
CONCERN FOR THE LOWEST 3KFT JUST OFF THE SURFACE DURING TAKEOFF AND
LANDING FOR ALL TERMINALS. OTHERWISE...MVFR/IFR CEILINGS ARE
EXPECTED THROUGHOUT THE DAY AND NIGHT. GUSTY WINDS WILL ALSO
PERSIST THROUGH THE DAY.
PREV DISCUSSION... /ISSUED 457 AM CST MON FEB 23 2015/
SHORT TERM (TODAY THROUGH TUESDAY)...
EARLY MORNING OBSERVATIONS SHOW THE FREEZING LINE ROUGHLY ALONG A
GEORGETOWN TO BOERNE TO COMSTOCK LINE. OBSERVATIONS ALSO SHOW
LIGHT MIXED PRECIPITATION FALLING ACROSS THE HILL COUNTRY WITH
ONLY TRACE AMOUNTS REPORTED SO FAR. OTHERWISE...RADAR ECHOES
GENERALLY ON THE INCREASE EARLY THIS MORNING...ESPECIALLY ACROSS
THE NORTHERN HILL COUNTRY INCLUDING KERR...GILLESPIE...LLANO AND
BURNET COUNTIES. THE LATEST HRRR AND NAM12 MODELS TEND TO FAVOR
THE ABOVE MENTIONED AREAS FOR PRECIPITATION TODAY AND WE HAVE
PLACED THE HIGHEST CHANCE FOR WINTRY PRECIPITATION HERE. WE/LL
NEED TO MONITOR THESE AREAS CAREFULLY AS ICE ACCUMULATIONS COULD
ADD UP QUICKER IF MULTIPLE ROUNDS OF PRECIPITATION DEVELOP.
OTHERWISE...WE STILL EXPECT WINTRY PRECIPITATION IN THE FORM OF
FREEZING RAIN TO OCCUR ACROSS THE SOUTHERN EDWARDS PLATEAU...HILL
COUNTRY AND PORTIONS OF THE INTERSTATE 35 CORRIDOR MAINLY NORTH OF
SAN MARCOS. WE STILL EXPECT ICE ACCUMULATIONS TO REMAIN AT OR
BELOW 1/10 OF AN INCH...WITH THE MAIN IMPACTS BEING ON BRIDGES AND
ELEVATED ROADWAYS. THE WINTER WEATHER ADVISORY WILL REMAIN IN
EFFECT UNTIL 6 PM TODAY.
OTHERWISE...TEMPERATURES WILL EITHER REMAIN STEADY OF SLOWLY FALL
TODAY DUE TO THE COMBINATION OF COLD AIR ADVECTION...CLOUD COVER
AND LIGHT PRECIPITATION. FOR THE EVENING AND OVERNIGHT HOURS...WE
EXPECT A FAIRLY QUICK DECREASE IN PRECIPITATION CHANCES FROM WEST
TO EAST ACROSS THE REGION. WE CONTEMPLATED EXPANDING THE WINTER
WEATHER ADVISORY FARTHER EAST TO COVER AREAS MAINLY NORTH OF
I-10/EAST OF I-35. HOWEVER...THE MODELS HAVE BEEN CONSISTENT IN
SHOWING A RATHER QUICK DECREASE IN THE PRECIPITATION THIS EVENING.
WE/LL CONTINUE TO HIGHLIGHT THIS REGION IN A SPECIAL WEATHER
STATEMENT TO COVER THE COLD TEMPERATURES AND POTENTIAL FOR LIGHT
WINTRY PRECIPITATION. PRECIPITATION CHANCES TEMPORARILY DECREASE
ON TUESDAY AS MID-LEVEL DRYING/WEAK SUBSIDENCE MOVE IN FROM THE
WEST.
LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...
ANOTHER UPPER LEVEL TROUGH APPROACHES SOUTH CENTRAL TEXAS FROM THE
WEST TUESDAY NIGHT. THE LATEST ROUND OF MODEL GUIDANCE IS SHOWING
THIS SYSTEM TO BE A LITTLE STRONGER WHEN COMPARED TO PREVIOUS
RUNS. WE HAVE INCREASED PRECIPITATION CHANCES SLIGHTLY FOR TUESDAY
NIGHT AND WEDNESDAY. AT THIS TIME...TEMPERATURES ARE EXPECTED TO
REMAIN ABOVE FREEZING TUESDAY NIGHT...SO WE/LL KEEP THE
PRECIPITATION AS ALL LIQUID. AS THE ABOVE MENTIONED UPPER LEVEL
STORM SYSTEM DEPARTS THE REGION BY LATE WEDNESDAY... ANOTHER
SYSTEM MOVES THROUGH ON THURSDAY. WE/LL KEEP THE FORECAST DRY AS
MOISTURE WILL BE LACKING. WE DO EXPECT ANOTHER SHOT OF COOLER AIR
TO MOVE THROUGH ON THURSDAY...FOLLOWED BY COOLER TEMPERATURES ON
FRIDAY. WE/LL KEEP A SLIGHT CHANCE FOR LIGHT RAIN IN THE FORECAST
FRIDAY THROUGH SUNDAY AS SOUTHERLY FLOW JUST ABOVE THE COLD
SURFACE AIR BEGINS TO SET UP A WARM AIR ADVECTION PATTERN.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 33 30 43 36 58 / 70 30 20 30 30
AUSTIN BERGSTROM INTL AIRPORT 34 30 43 34 57 / 70 30 20 30 30
NEW BRAUNFELS MUNI AIRPORT 36 30 45 37 61 / 60 30 10 30 20
BURNET MUNI AIRPORT 31 26 41 34 57 / 80 30 20 30 20
DEL RIO INTL AIRPORT 38 34 52 41 68 / 50 10 10 10 -
GEORGETOWN MUNI AIRPORT 33 27 42 34 56 / 70 40 20 30 30
HONDO MUNI AIRPORT 37 32 48 38 65 / 50 20 10 20 -
SAN MARCOS MUNI AIRPORT 35 30 44 37 59 / 70 30 10 30 20
LA GRANGE - FAYETTE REGIONAL 38 31 43 38 57 / 70 40 20 30 30
SAN ANTONIO INTL AIRPORT 38 31 45 38 62 / 60 30 10 20 10
STINSON MUNI AIRPORT 39 32 46 39 63 / 60 30 10 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS...
GILLESPIE...HAYS...KENDALL...KERR...LLANO...REAL...TRAVIS...VAL
VERDE...WILLIAMSON.
&&
$$
MESOSCALE/AVIATION...04
SYNOPTIC/GRIDS...17
PUBLIC SERVICE/DATA COLLECTION...00
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
530 AM CST MON FEB 23 2015
.AVIATION UPDATE...FOR 12Z TAF PACKAGE...
CURRENT CONDITIONS WILL LIKELY PERSIST THROUGH ENTIRE TAF PERIOD.
THERE IS SOME CONCERN FOR -FZDZ THIS MORNING FOR KAUS SO INCLUDED
TEMPO GROUP TO HANDLE THAT. OTHERWISE -DZ EXPECTED FOR ALL
TERMINALS TODAY. AS PREVIOUS FORECAST MENTIONED...ICING WILL BE A
CONCERN FOR THE LOWEST 3KFT JUST OFF THE SURFACE DURING TAKEOFF AND
LANDING FOR ALL TERMINALS. OTHERWISE...MVFR/IFR CEILINGS ARE
EXPECTED THROUGHOUT THE DAY AND NIGHT. GUSTY WINDS WILL ALSO
PERSIST THROUGH THE DAY.
&&
.PREV DISCUSSION... /ISSUED 457 AM CST MON FEB 23 2015/
SHORT TERM (TODAY THROUGH TUESDAY)...
EARLY MORNING OBSERVATIONS SHOW THE FREEZING LINE ROUGHLY ALONG A
GEORGETOWN TO BOERNE TO COMSTOCK LINE. OBSERVATIONS ALSO SHOW
LIGHT MIXED PRECIPITATION FALLING ACROSS THE HILL COUNTRY WITH
ONLY TRACE AMOUNTS REPORTED SO FAR. OTHERWISE...RADAR ECHOES
GENERALLY ON THE INCREASE EARLY THIS MORNING...ESPECIALLY ACROSS
THE NORTHERN HILL COUNTRY INCLUDING KERR...GILLESPIE...LLANO AND
BURNET COUNTIES. THE LATEST HRRR AND NAM12 MODELS TEND TO FAVOR
THE ABOVE MENTIONED AREAS FOR PRECIPITATION TODAY AND WE HAVE
PLACED THE HIGHEST CHANCE FOR WINTRY PRECIPITATION HERE. WE/LL
NEED TO MONITOR THESE AREAS CAREFULLY AS ICE ACCUMULATIONS COULD
ADD UP QUICKER IF MULTIPLE ROUNDS OF PRECIPITATION DEVELOP.
OTHERWISE...WE STILL EXPECT WINTRY PRECIPITATION IN THE FORM OF
FREEZING RAIN TO OCCUR ACROSS THE SOUTHERN EDWARDS PLATEAU...HILL
COUNTRY AND PORTIONS OF THE INTERSTATE 35 CORRIDOR MAINLY NORTH OF
SAN MARCOS. WE STILL EXPECT ICE ACCUMULATIONS TO REMAIN AT OR
BELOW 1/10 OF AN INCH...WITH THE MAIN IMPACTS BEING ON BRIDGES AND
ELEVATED ROADWAYS. THE WINTER WEATHER ADVISORY WILL REMAIN IN
EFFECT UNTIL 6 PM TODAY.
OTHERWISE...TEMPERATURES WILL EITHER REMAIN STEADY OF SLOWLY FALL
TODAY DUE TO THE COMBINATION OF COLD AIR ADVECTION...CLOUD COVER
AND LIGHT PRECIPITATION. FOR THE EVENING AND OVERNIGHT HOURS...WE
EXPECT A FAIRLY QUICK DECREASE IN PRECIPITATION CHANCES FROM WEST
TO EAST ACROSS THE REGION. WE CONTEMPLATED EXPANDING THE WINTER
WEATHER ADVISORY FARTHER EAST TO COVER AREAS MAINLY NORTH OF
I-10/EAST OF I-35. HOWEVER...THE MODELS HAVE BEEN CONSISTENT IN
SHOWING A RATHER QUICK DECREASE IN THE PRECIPITATION THIS EVENING.
WE/LL CONTINUE TO HIGHLIGHT THIS REGION IN A SPECIAL WEATHER
STATEMENT TO COVER THE COLD TEMPERATURES AND POTENTIAL FOR LIGHT
WINTRY PRECIPITATION. PRECIPITATION CHANCES TEMPORARILY DECREASE
ON TUESDAY AS MID-LEVEL DRYING/WEAK SUBSIDENCE MOVE IN FROM THE
WEST.
LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...
ANOTHER UPPER LEVEL TROUGH APPROACHES SOUTH CENTRAL TEXAS FROM THE
WEST TUESDAY NIGHT. THE LATEST ROUND OF MODEL GUIDANCE IS SHOWING
THIS SYSTEM TO BE A LITTLE STRONGER WHEN COMPARED TO PREVIOUS
RUNS. WE HAVE INCREASED PRECIPITATION CHANCES SLIGHTLY FOR TUESDAY
NIGHT AND WEDNESDAY. AT THIS TIME...TEMPERATURES ARE EXPECTED TO
REMAIN ABOVE FREEZING TUESDAY NIGHT...SO WE/LL KEEP THE
PRECIPITATION AS ALL LIQUID. AS THE ABOVE MENTIONED UPPER LEVEL
STORM SYSTEM DEPARTS THE REGION BY LATE WEDNESDAY... ANOTHER
SYSTEM MOVES THROUGH ON THURSDAY. WE/LL KEEP THE FORECAST DRY AS
MOISTURE WILL BE LACKING. WE DO EXPECT ANOTHER SHOT OF COOLER AIR
TO MOVE THROUGH ON THURSDAY...FOLLOWED BY COOLER TEMPERATURES ON
FRIDAY. WE/LL KEEP A SLIGHT CHANCE FOR LIGHT RAIN IN THE FORECAST
FRIDAY THROUGH SUNDAY AS SOUTHERLY FLOW JUST ABOVE THE COLD
SURFACE AIR BEGINS TO SET UP A WARM AIR ADVECTION PATTERN.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 34 30 43 36 58 / 70 30 20 30 30
AUSTIN BERGSTROM INTL AIRPORT 35 30 43 34 57 / 70 30 20 30 30
NEW BRAUNFELS MUNI AIRPORT 36 32 45 37 61 / 60 30 10 30 20
BURNET MUNI AIRPORT 31 26 41 34 57 / 80 30 20 30 20
DEL RIO INTL AIRPORT 38 36 52 41 68 / 50 10 10 10 -
GEORGETOWN MUNI AIRPORT 33 27 42 34 56 / 70 40 20 30 30
HONDO MUNI AIRPORT 37 33 48 38 65 / 50 20 10 20 -
SAN MARCOS MUNI AIRPORT 36 31 44 37 59 / 70 30 10 30 20
LA GRANGE - FAYETTE REGIONAL 38 33 43 38 57 / 70 40 20 30 30
SAN ANTONIO INTL AIRPORT 38 32 45 38 62 / 60 30 10 20 10
STINSON MUNI AIRPORT 39 33 46 39 63 / 60 30 10 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS...
GILLESPIE...HAYS...KENDALL...KERR...LLANO...REAL...TRAVIS...VAL
VERDE...WILLIAMSON.
&&
$$
MESOSCALE/AVIATION...03
SYNOPTIC/GRIDS...24
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
457 AM CST MON FEB 23 2015
.SHORT TERM (TODAY THROUGH TUESDAY)...
EARLY MORNING OBSERVATIONS SHOW THE FREEZING LINE ROUGHLY ALONG A
GEORGETOWN TO BOERNE TO COMSTOCK LINE. OBSERVATIONS ALSO SHOW
LIGHT MIXED PRECIPITATION FALLING ACROSS THE HILL COUNTRY WITH
ONLY TRACE AMOUNTS REPORTED SO FAR. OTHERWISE...RADAR ECHOES
GENERALLY ON THE INCREASE EARLY THIS MORNING...ESPECIALLY ACROSS
THE NORTHERN HILL COUNTRY INCLUDING KERR...GILLESPIE...LLANO AND
BURNET COUNTIES. THE LATEST HRRR AND NAM12 MODELS TEND TO FAVOR
THE ABOVE MENTIONED AREAS FOR PRECIPITATION TODAY AND WE HAVE
PLACED THE HIGHEST CHANCE FOR WINTRY PRECIPITATION HERE. WE/LL
NEED TO MONITOR THESE AREAS CAREFULLY AS ICE ACCUMULATIONS COULD
ADD UP QUICKER IF MULTIPLE ROUNDS OF PRECIPITATION DEVELOP.
OTHERWISE...WE STILL EXPECT WINTRY PRECIPITATION IN THE FORM OF
FREEZING RAIN TO OCCUR ACROSS THE SOUTHERN EDWARDS PLATEAU...HILL
COUNTRY AND PORTIONS OF THE INTERSTATE 35 CORRIDOR MAINLY NORTH OF
SAN MARCOS. WE STILL EXPECT ICE ACCUMULATIONS TO REMAIN AT OR
BELOW 1/10 OF AN INCH...WITH THE MAIN IMPACTS BEING ON BRIDGES AND
ELEVATED ROADWAYS. THE WINTER WEATHER ADVISORY WILL REMAIN IN
EFFECT UNTIL 6 PM TODAY.
OTHERWISE...TEMPERATURES WILL EITHER REMAIN STEADY OF SLOWLY FALL
TODAY DUE TO THE COMBINATION OF COLD AIR ADVECTION...CLOUD COVER
AND LIGHT PRECIPITATION. FOR THE EVENING AND OVERNIGHT HOURS...WE
EXPECT A FAIRLY QUICK DECREASE IN PRECIPITATION CHANCES FROM WEST
TO EAST ACROSS THE REGION. WE CONTEMPLATED EXPANDING THE WINTER
WEATHER ADVISORY FARTHER EAST TO COVER AREAS MAINLY NORTH OF
I-10/EAST OF I-35. HOWEVER...THE MODELS HAVE BEEN CONSISTENT IN
SHOWING A RATHER QUICK DECREASE IN THE PRECIPITATION THIS EVENING.
WE/LL CONTINUE TO HIGHLIGHT THIS REGION IN A SPECIAL WEATHER
STATEMENT TO COVER THE COLD TEMPERATURES AND POTENTIAL FOR LIGHT
WINTRY PRECIPITATION. PRECIPITATION CHANCES TEMPORARILY DECREASE
ON TUESDAY AS MID-LEVEL DRYING/WEAK SUBSIDENCE MOVE IN FROM THE
WEST.
&&
.LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...
ANOTHER UPPER LEVEL TROUGH APPROACHES SOUTH CENTRAL TEXAS FROM THE
WEST TUESDAY NIGHT. THE LATEST ROUND OF MODEL GUIDANCE IS SHOWING
THIS SYSTEM TO BE A LITTLE STRONGER WHEN COMPARED TO PREVIOUS
RUNS. WE HAVE INCREASED PRECIPITATION CHANCES SLIGHTLY FOR TUESDAY
NIGHT AND WEDNESDAY. AT THIS TIME...TEMPERATURES ARE EXPECTED TO
REMAIN ABOVE FREEZING TUESDAY NIGHT...SO WE/LL KEEP THE
PRECIPITATION AS ALL LIQUID. AS THE ABOVE MENTIONED UPPER LEVEL
STORM SYSTEM DEPARTS THE REGION BY LATE WEDNESDAY... ANOTHER
SYSTEM MOVES THROUGH ON THURSDAY. WE/LL KEEP THE FORECAST DRY AS
MOISTURE WILL BE LACKING. WE DO EXPECT ANOTHER SHOT OF COOLER AIR
TO MOVE THROUGH ON THURSDAY...FOLLOWED BY COOLER TEMPERATURES ON
FRIDAY. WE/LL KEEP A SLIGHT CHANCE FOR LIGHT RAIN IN THE FORECAST
FRIDAY THROUGH SUNDAY AS SOUTHERLY FLOW JUST ABOVE THE COLD
SURFACE AIR BEGINS TO SET UP A WARM AIR ADVECTION PATTERN.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 34 30 43 36 58 / 70 30 20 30 30
AUSTIN BERGSTROM INTL AIRPORT 35 30 43 34 57 / 70 30 20 30 30
NEW BRAUNFELS MUNI AIRPORT 36 32 45 37 61 / 60 30 10 30 20
BURNET MUNI AIRPORT 31 26 41 34 57 / 80 30 20 30 20
DEL RIO INTL AIRPORT 38 36 52 41 68 / 50 10 10 10 -
GEORGETOWN MUNI AIRPORT 33 27 42 34 56 / 70 40 20 30 30
HONDO MUNI AIRPORT 37 33 48 38 65 / 50 20 10 20 -
SAN MARCOS MUNI AIRPORT 36 31 44 37 59 / 70 30 10 30 20
LA GRANGE - FAYETTE REGIONAL 38 33 43 38 57 / 70 40 20 30 30
SAN ANTONIO INTL AIRPORT 38 32 45 38 62 / 60 30 10 20 10
STINSON MUNI AIRPORT 39 33 46 39 63 / 60 30 10 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS...
GILLESPIE...HAYS...KENDALL...KERR...LLANO...REAL...TRAVIS...VAL
VERDE...WILLIAMSON.
&&
$$
MESOSCALE/AVIATION...03
SYNOPTIC/GRIDS...24
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1155 PM CST SUN FEB 22 2015
.AVIATION...
NOT MUCH CHANGE TO THE PREVIOUS TAF PACKAGE WITH REGARDS TO TIMING
AND TYPE OF PRECIPITATION EXPECTED OVER THE NEXT 18 HOURS OR SO.
SOME LIGHT FREEZING DRIZZLE WILL LINGER ACROSS THE METROPLEX TAF
SITES FOR THE NEXT FEW HOURS WITH GENERALLY IFR CEILINGS. THE NEXT
ROUND OF PRECIPITATION ASSOCIATED WITH ANOTHER SHORT WAVE IS
CURRENTLY DEVELOPING ACROSS THE PERMIAN BASIN AND SHOULD ARRIVE AT
THE METROPLEX TAF SITES AROUND SUNRISE. THIS PRECIPITATION WILL
MOSTLY BE IN THE FORM OF SLEET. HIGH RES MODEL SOLUTIONS CONTINUE
TO INDICATE CONVECTIVE BANDS WITH SOME THUNDER SLEET. THE MOST
LIKELY PERIOD FOR SLEET ACROSS THE METROPLEX TERMINALS WILL BE
BETWEEN 12 AND 18Z. SLEET CHANCES WILL DECREASE AFTER 18Z EXCEPT
FOR WACO WHERE SLEET WILL BE MOST LIKELY MONDAY AFTERNOON. OVERALL
CEILINGS WILL REMAIN BETWEEN 700 AND 1000 FT THROUGH THE DAY AND
EVENING MONDAY. ALL PRECIPITATION SHOULD END BY 00Z TUESDAY.
A NORTH WIND WILL PREVAIL OVERNIGHT AT SPEEDS BETWEEN 15 AND 20
KNOTS SUSTAINED ALONG WITH SOME HIGHER GUSTS. A NORTH WIND WILL
CONTINUE ON MONDAY BUT SPEEDS SHOULD DECREASE THROUGH THE DAY AND
FALL BELOW 12 KNOTS AFTER SUNSET.
79
&&
.UPDATE...
AS THE FIRST WAVE OF PRECIPITATION ENDS THIS EVENING...A LARGE
AREA OF FREEZING DRIZZLE HAS DEVELOPED NORTH TO WEST OF THE DFW
METROPLEX INCLUDING TARRANT COUNTY. 850 MB WINDS ARE OUT OF THE
EAST OVERRUNNING THE COLD SURFACE AIR...BUT THEY HAVE PREVAILED
FROM THIS DIRECTION MOST OF THE EVENING WITHOUT DRIZZLE
DEVELOPING EARLIER IN THE NIGHT. THE RAP SHOWS A WEAK SHORTWAVE
MOVING OVERHEAD WHICH IS LIKELY PROVIDING ADDITIONAL LIFT FOR THE
DRIZZLE TO DEVELOP...IN COMBINATION WITH THE ISENTROPIC LIFT OVER
THE COLD SURFACE LAYER. THE RAP SHOWS THIS SHORTWAVE MOVING EAST
OF THE REGION BY MIDNIGHT AND EXPECT MOST OF THE DRIZZLE WILL END
AROUND THAT TIME. HOWEVER...THE DRIZZLE IS ALREADY AND WILL
CREATE A THIN LAYER OF ICE ON ELEVATED SURFACES...METAL
OBJECTS...AND LIKELY BRIDGES AND OVERPASSES THAT ALREADY DO NOT
HAVE ICE FROM THE FREEZING RAIN/SLEET EARLIER. IN
ADDITION...RESIDUAL WATER REMAINING ON ROADWAYS TONIGHT MAY FREEZE
OVERNIGHT AS TEMPERATURES FALL INTO THE 20S OVER A GOOD PORTION OF
THE REGION. HOWEVER...THE STRONG WINDS WILL CONTINUE THROUGH THE
OVERNIGHT HOURS WHICH MAY ALSO HELP TO EVAPORATE ANY WATER ON
ROADWAYS...BUT NOT WHERE DRIZZLE IS OCCURRING.
THE NEXT WAVE OF PRECIPITATION IS STILL EXPECTED TO ARRIVE BETWEEN
1-3 AM...MOVING IN FROM THE WEST OR SOUTHWEST. NO CHANGES ARE
NEEDED TO THE CURRENT WARNING AND ADVISORY PRODUCTS...HOWEVER...IF
THE NEXT ROUND OF PRECIPITATION IS SLIGHTLY FARTHER SOUTH THAN THE
LATEST GUIDANCE SUGGESTS...IT IS POSSIBLE PORTIONS OF THE ADVISORY
MAY HAVE TO BE UPGRADED TO A WARNING DUE TO HIGHER ACCUMULATIONS
OF SLEET. UNFORTUNATELY WE WILL HAVE TO WAIT AND MONITOR THE RADAR
TRENDS LATE TONIGHT AND EARLY MONDAY MORNING BEFORE BEING ABLE TO
CONFIDENTLY MAKE THAT DECISION.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 400 PM CST SUN FEB 22 2015/
...SIGNIFICANT WINTER STORM TAKING SHAPE FOR OVERNIGHT AND EARLY
MONDAY ACROSS NORTH TEXAS...
.SIGNIFICANT FORECAST CHANGES...
WINTER STORM WARNING START TIME HAS BEEN MOVED UP TO START NOW.
WINTER WEATHER ADVISORY START TIME HAS BEEN MOVED UP TO 9PM.
SLEET ACCUMULATIONS HAVE BEEN BUMPED UP SLIGHTLY ACROSS THE
NORTHWEST PARTS OF THE CWA. ICE ACCUMULATIONS FROM FREEZING RAIN
HAVE BEEN NUDGED UP SLIGHTLY BUT REMAIN BELOW WARNING CRITERIA
FARTHER SOUTH. HOURLY TEMPERATURE TRENDS HAVE BEEN ADJUSTED TO
REFLECT CURRENT POSITION OF COLDER AIR. HIGH TEMPERATURES ON
MONDAY HAVE BEEN LOWERED BY 2-3 DEGREES. NO OTHER SIGNIFICANT
FORECAST CHANGES THIS AFTERNOON.
.TECHNICAL DISCUSSION...
MUCH COLDER AIR CONTINUES TO FILTER INTO NORTH TEXAS THIS
AFTERNOON WITH SUB FREEZING TEMPERATURES NOW MOVING INTO THE
NORTHWEST COUNTIES. PRECIPITATION HAS DIMINISHED IN INTENSITY
ACROSS THESE AREAS WHICH SHOULD LIMIT ANY FREEZING RAIN POTENTIAL
THROUGH THE EVENING HOURS. FARTHER EAST...A COLD RAIN WILL
CONTINUE THROUGH THE EARLY EVENING AS THE FIRST WAVE OF LIFT MOVES
TO THE NORTHEAST. TEMPERATURES ARE GENERALLY IN THE MID TO UPPER
30S AND LOWER 40S WHERE THIS PRECIPITATION IS OCCURRING SO NO
FREEZING RAIN IS EXPECTED. SOME AREAS HAVE ALREADY PICKED UP CLOSE
TO AN INCH OF RAIN BUT THIS INTENSITY WILL DIMINISH THROUGH
EVENING.
SIGNS OF THE SECOND WAVE OF ASCENT ARE ALREADY BEING INDICATED ON
RADAR AND WATER VAPOR IMAGERY ACROSS WEST TEXAS. SOME AREAS OF
PRECIPITATION HAVE ALREADY DEVELOPED BUT THIS SHOULD GENERALLY
REMAIN SCATTERED OVER THE NEXT SEVERAL HOURS AS THE BETTER FORCING
WILL ARRIVE DURING THE OVERNIGHT HOURS. WE ARE EXPECTED TO SEE A
LULL IN THE PRECIPITATION LATER THIS EVENING THROUGH MIDNIGHT OR
SO...BUT IT WONT BE COMPLETELY VOID OF ACTIVITY. THERE WILL LIKELY
BE INTERMITTENT AREAS OF PRECIPITATION THAT DEVELOP IN POCKETS OF
STRONGER FORCING THAT STREAM ACROSS NORTH TEXAS IN THE SOUTHWEST
FLOW ALOFT. ANY PRECIPITATION THAT DEVELOPS LATE THIS EVENING
COULD BE IN THE FORM OF A FREEZING RAIN/SLEET MIX ACROSS THE WEST
AND NORTHWEST PARTS OF THE CWA. THE FREEZING LINE WILL SURGE SOUTH
THIS EVENING ACROSS THE WESTERN COUNTIES AND IT WILL TAKE A LITTLE
LONGER FARTHER EAST. IT SHOULD BE MOVING INTO THE METROPLEX BY 0Z
OR A LITTLE LATER. BY 3-4AM...MOST AREAS WITH THE EXCEPTION OF THE
SOUTHEAST COUNTIES SHOULD BE AT OR BELOW FREEZING.
THE STRONGEST FORCING LOOKS LIKE IT WILL OVERSPREAD NORTH TEXAS IN
THE 3-5AM TIMEFRAME WITH WIDESPREAD PRECIPITATION CONTINUING INTO
THE MORNING HOURS ON MONDAY. THE COMPACT UPPER LOW SOUTH OF
CALIFORNIA IS IN THE PROCESS OF EJECTING NORTHEAST NOW AND ANOTHER
DISTURBANCE APPEARS TO BE EMBEDDED IN THE FLOW ACROSS NORTHWEST
MEXICO. THESE SEEM TO BE THE FEATURES THAT REALLY PROVIDE THE
FORCING FOR ASCENT LATE TONIGHT. RIGHT NOW... WE THINK THE
HEAVIEST PRECIPITATION WILL OCCUR ALONG A LINE FROM NEAR EASTLAND
TO DFW TO SHERMAN...AND AREAS NORTHWEST OF THERE THROUGH ABOUT
10AM ON MONDAY. LATEST HIGH RESOLUTION TTU-WRF AND 4KM NAM
CONTINUE TO YIELD HIGH CONFIDENCE IN THE CURRENT FORECAST AS BOTH
CONTINUE TO STRONGLY INDICATE CONVECTIVE ELEMENTS TO THE
PRECIPITATION. SREF PLUMES OF MUCAPE AND ANALYSIS OF ALL AVAILABLE
FORECAST SOUNDINGS INDICATE THAT ANYWHERE FROM 100-150J/KG OF
ELEVATED INSTABILITY WILL BE PRESENT. THIS WILL SUPPORT
THUNDERSLEET THROUGH THE MORNING HOURS. BURSTS OF SLEET CAN
QUICKLY ACCUMULATE TO AN INCH OR MORE IN A SHORT PERIOD OF TIME.
AS OF THIS AFTERNOON...WE THINK THAT MOST AREAS IN THE CURRENT
WARNING WILL SEE BETWEEN 1/2 AND 1 INCH OF SLEET. FARTHER
NORTHWEST...FROM FORT WORTH TO BOWIE...ACCUMULATIONS OF 1 TO 1 1/2
INCH OF SLEET WITH HEAVIER AMOUNTS WILL BE POSSIBLE. SOME LIGHT
FREEZING RAIN WILL ALSO BE POSSIBLE THROUGH MORNING BUT ICE
ACCUMULATIONS SHOULD GENERALLY BE LESS THAN 1/10 OF AN INCH.
FARTHER SOUTH OF THE METROPLEX...WHERE THE CURRENT ADVISORY IS
POSTED...THE WARM NOSE WILL BE A LITTLE MORE STOUT INITIALLY.
THIS MAY KEEP PRECIPITATION ALL LIQUID AS OPPOSED TO SLEET. WITH
TEMPERATURES FALLING BELOW FREEZING...SOME LIGHT ICING IS
EXPECTED. THIS WILL BE WORST ON BRIDGES AND OVERPASSES. MOST OF
THE PRECIPITATION SHOULD MOVE EAST OF THE AREA BY LATE MONDAY BUT
WE WILL KEEP SOME LOW CHANCES IN THROUGH THE EVENING. SOME LIGHT
FREEZING RAIN OR DRIZZLE MAY BE POSSIBLE DURING THIS TIME WITH
LITTLE ADDITIONAL IMPACT.
TEMPERATURES ON MONDAY ARE NOT EXPECTED TO RISE ABOVE FREEZING SO
ANY ACCUMULATIONS OF SLEET/ICE WILL NOT MELT. THIS WILL RESULT IN
CONTINUED TRAVEL PROBLEMS. TEMPERATURES ARE EXPECTED TO RISE ABOVE
FREEZING BY MIDDAY TUESDAY.
LITTLE CHANGES MADE TO THE END OF THE WEEK SYSTEM AS THERE IS
STILL CONSIDERABLY MODEL UNCERTAINTY. WE HAVE CONTINUED WITH A
RAIN/SNOW MIX LATE THURSDAY INTO LATE FRIDAY ACROSS MUCH OF THE
AREA.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 26 27 25 39 31 / 80 100 20 20 10
WACO, TX 30 31 24 38 33 / 80 90 30 20 30
PARIS, TX 25 25 25 36 28 / 50 100 30 20 10
DENTON, TX 23 25 20 36 29 / 80 100 10 10 10
MCKINNEY, TX 26 26 23 38 28 / 70 100 20 10 10
DALLAS, TX 28 29 26 39 31 / 80 100 20 20 10
TERRELL, TX 29 29 25 37 30 / 70 100 20 20 10
CORSICANA, TX 30 30 26 38 32 / 70 90 30 20 20
TEMPLE, TX 31 32 25 40 34 / 90 90 30 20 30
MINERAL WELLS, TX 24 25 20 36 28 / 100 100 10 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR TXZ091>095-
100>107-115>123-129>134-141.
WINTER WEATHER ADVISORY UNTIL 6 PM CST MONDAY FOR TXZ135-142>148-
156>162-174-175.
&&
$$
79/82
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1101 PM CST Sun Feb 22 2015
.AVIATION...
/06Z TAFS/
Generally IFR/LIFR conditions are being experienced at all TAF sites
late this evening and should continue through Tuesday morning. Areas
of light freezing drizzle are also occurring. Freezing rain/sleet is
forecast to develop after midnight, mainly affecting KABI and KSJT,
then moving east of the area by mid morning Monday. Areas of light
freezing drizzle may continue into early afternoon Monday. Northeast
winds of 12 to 20 knots, with higher gusts, will diminish to 8 to 12
knots late Monday morning.
&&
.PREV DISCUSSION... /ISSUED 955 PM CST Sun Feb 22 2015/
UPDATE...
Based on radar data, it appears we`re in a bit of a lull across
the area now. However, calls across the CWA and automated surface
observations indicate that widespread, light freezing drizzle is
occurring in many areas. Temperatures continue to run a few
degrees below even the coldest guidance, with current readings in
the 20s everywhere excluding the I-10 corridor (lower 30s).
Temperatures will continue to slowly drop tonight, setting
the stage for the next shortwave trough.
The primary wave looks to be moving across the northern Baja
Peninsula at this time, with notable forced ascent downstream
over AZ, NM, and northern Mexico. There is a band of frontogenetic
forcing sloping up and over the cold dome from north to south that
is progged to persist into Monday morning before weakening. This
area of mesoscale lift should be enhanced by the approaching
shortwave energy. The going forecast looks to be in relatively
good shape. The wx grids were modified for this evening, with
widespread drizzle and only a chance for sleet mentioned areawide.
However, after midnight, we expect additional precipitation to
develop.
Point soundings suggest the favored precipitation types to be
sleet and freezing rain. However, both the NAM and RAP soundings
show the cold near surface layer (below the inversion) to be near
-10C. While this generally favors supercooled liquid hydrometeors,
this is a borderline temperature for the activation of ice nuclei.
This would account for the very light snow we`ve had reported over
the past few hours. Expect snow accumulations to be a dusting or
less. With elevated instability in place, this precipitation
should be more convective in nature, with the potential for
thundersleet overnight. In areas that do experience thunder, the
enhanced convective updrafts may lead to localized higher amounts
of sleet and/or snow.
Precipitation is expected to diminish by Monday afternoon,
although freezing drizzle will remain possible even into Monday
evening. Expect surface temperatures on Monday to remain well
below freezing, with highs in the mid/upper 20s. There may be just
enough radiation coming through the thick overcast to improve road
surfaces on Monday, but most of the ice should persist into
Tuesday morning.
Johnson
PREV DISCUSSION... /ISSUED 514 PM CST Sun Feb 22 2015/
AVIATION...
/00Z TAFS/
Generally LIFR/IFR conditions are being experienced at all sites
this evening and are forecast to continue through the next 24
hours. Light freezing drizzle continues at KABI and is forecast
to develop at KSJT around 00z as temperatures drop to or below
freezing. Light drizzle will continue at the other sites then
transition to light freezing drizzle late this evening as
temperatures drop below freezing. Areas of light freezing
rain/sleet may develop after midnight, mainly at KABI and KSJT.
Northeast winds of 12 to 20 knots, with higher gusts, will
decrease to 8 to 12 knots by late morning Monday.
PREV DISCUSSION... /ISSUED 409 PM CST Sun Feb 22 2015/
SHORT TERM...
(Tonight through Tuesday morning)
The much talked about winter storm is beginning to affect the
area. Another cold front was crossing the area at 3 PM and was
located along an Ozona to just south of Brownwood line, with cold
air rapidly invading the area behind this front. Trends in the
observations are showing temperatures dropping 5 to 10 degrees per
hour behind it. In fact, many areas along/north of Interstate 20
have already dropped below freezing with freezing rain, sleet, and
ice accumulations already occurring per social media, phone calls,
and observations. Given these developments over the last few
hours, and after coordinating with surrounding offices, the Winter
Storm Warning start time has been increased to 4 PM this
afternoon.
Things continue to look like they`ll get messy through tomorrow.
The numerical models remain consistent dropping temperatures
into the lower to mid 20s across the warned area, and near
freezing farther south, with not much recovery tomorrow afternoon.
They have also trended stronger/farther south with their
convective signature. The Storm Prediction Center has most of West
Central Texas in a risk for thunder tonight/tomorrow and model
soundings show 100-250 J/kg of MUCAPE across the entire forecast
area during this period. As a result, thunder was included in all
zones for tonight through mid afternoon tomorrow.
LONG TERM...
(Tuesday through Sunday)
All hands on board for the first winter storm, so this part of the
discussion will be brief. Warming trend starts on Tuesday
afternoon, although it will be modest. A few breaks in the clouds
will allow a little sun, enough to allow temperatures to climb
into the 40s. Another upper level low will drop into the southwest
US, with return flow ahead of it allowing readings to climb into
the 60s on Wednesday. Next arctic front moves across the area for
Thursday and Friday, just ahead of the upper level trough moving
across. GFS and the ECMWF have some differences in the strength of
this system, with the GFS shearing it out a little faster. For
now, kept the compromise intact and have slight chance to chance
PoPs across the area. Models did warm just a tad, so was able to
shift the mention of snow a little farther north.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 21 25 20 40 29 / 90 80 10 10 5
San Angelo 25 29 25 46 31 / 90 70 10 10 5
Junction 29 32 28 48 34 / 80 70 10 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING until 6 PM CST Monday FOR THE FOLLOWING
ZONES: Brown...Callahan...Coke...Coleman...Concho...Fisher...
Haskell...Irion...Jones...Nolan...Runnels...Shackelford...
Sterling...Taylor...Throckmorton...Tom Green.
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR THE FOLLOWING
ZONES: Crockett...Kimble...Mason...McCulloch...Menard...San
Saba...Schleicher...Sutton.
&&
$$
Daniels
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
533 PM CST TUE FEB 24 2015
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 238 PM CST TUE FEB 24 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN ARCTIC
COLD FRONT STRETCHING FROM AROUND WAUTOMA TO MARINETTE AND MOVING
EAST EARLY THIS AFTERNOON. SNOW SHOWERS DEVELOPED AHEAD OF THE
FRONT EARLIER TODAY AND LOCALLY DROPPED VSBYS TO A QUARTER OF A
MILE. THESE SNOW SHOWERS ARE NOW ENTERING LAKE MICHIGAN. OTHER
WEAKER SNOW SHOWERS EXIST RIGHT BEHIND THE FRONT. EXCEPT FOR THE
SNOW BELT...THESE SNOW SHOWERS SHOULD EXIT BY THE START OF THE
EVENING. WINDS ARE BECOMING STRONG AND GUSTY BEHIND THE FRONT WITH
SOME OBS REACHING UP TO 35 KNOTS OVER CENTRAL AND NORTH-CENTRAL
WISCONSIN. THESE GUSTY WINDS WILL SPREAD INTO EASTERN WISCONSIN
LATER THIS AFTERNOON. SOME CONCERN FOR THE DOOR PENINSULA AS WIND
DIRECTION AND PRESSURE RISES ARE FAVORABLE FOR NEAR WIND ADVISORY
WIND GUSTS FOR A FEW HOURS. THINK WILL FALL JUST SHORT OF THOSE
TYPES OF GUSTS THOUGH. PLENTY OF STRATO-CU AND SNOW SHOWERS WITHIN THE
ARCTIC AIR OVER THE ARROWHEAD AND HEADING TOWARDS NORTHERN
WISCONSIN. WINDS/TEMPS/WIND CHILLS/AND SNOW POTENTIAL ARE THE MAIN
FORECAST CONCERNS.
TONIGHT...THE ARCTIC COLD FRONT WILL EXIT NORTHEAST WISCONSIN LATE
IN THE AFTERNOON OR EARLY THIS EVENING. SHOULD SEE PRETTY GOOD WIND
GUSTS UP TO 40 MPH OVER DOOR COUNTY AS STRONG PRESSURE RISES ARRIVE
BEHIND THE FRONT EARLY THIS EVENING. GUSTS BETWEEN 30 AND 35 MPH
ARE POSSIBLE ELSEWHERE. THE WINDS SHOULD THEN SUBSIDE PRETTY
QUICKLY BY MID-EVENING AS ARCTIC AIR PLUNGES ACROSS NORTH-CENTRAL
AND NORTHEAST WISCONSIN...THOUGH WINDS SHOULD NOT DECOUPLE.
SCATTERED SNOW SHOWERS WILL LIKELY FOLLOW THE ARRIVAL OF THE
ARCTIC AIR ACROSS THE NORTH THIS EVENING...THEN DIMINISH/RETREAT
TO THE SNOWBELT AREAS OVERNIGHT. THE COMBINATION OF TEMPS FALLING
TO AROUND 10 OR 12 BELOW OVER N-C WISCONSIN AND PERSISTENT
NORTHWEST WINDS WILL HAVE WIND CHILLS FALLING BETWEEN 20 TO 25
BELOW OVER N-C WISCONSIN AND GENERALLY 10 TO 15 BELOW ELSEWHERE.
IN COORDINATION WITH WFOS MARQUETTE AND DULUTH...WILL NOT ISSUE A
WIND CHILL ADVISORY AND WILL INSTEAD HIGHLIGHT THE THREAT IN A
SPS.
WEDNESDAY...ARCTIC HIGH PRESSURE WILL REMAIN IN CONTROL ACROSS THE
REGION AS A WEAK DISTURBANCE SLIDES SOUTHEAST ACROSS THE CENTRAL
GREAT PLAINS. WILL SEE MID AND HIGH CLOUDS SPREAD OVERHEAD FROM
THIS DISTURBANCE...BUT NO REAL THREAT OF PRECIP THIS FAR INTO THE
ARCTIC AIR. BITTERLY COLD WIND CHILLS WILL BE MODERATING BY 9 OR 10
IN THE MORNING TO BETWEEN 10 AND 20 BELOW OVER N-C WISCONSIN. HIGHS
WILL BE RANGING FROM 5 TO 10 ABOVE OVER N-C WI TO 10 TO 15 FARTHER
SOUTH AND EAST.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 238 PM CST TUE FEB 24 2015
PATTERN ALOFT IS BEGINNING TO CHANGE...BUT NOT BEFORE ONE MORE
BATCH OF ARCTIC AIR PUSHES INTO THE AREA. EVENTUALLY A WESTERN
TROUGH WILL EMERGE AS THE RIDGE PREVIOUSLY IN PLACE REFORMS MORE
OVER THE PACIFIC. THE EASTERN TROUGH WILL RETREAT NORTH...AND
SOMETHING RESEMBLING A SOUTHERN STREAM WILL START TO BRING
SOUTHWEST FLOW ALOFT INTO WISCONSIN. THIS WILL BRING A WARMER AND
MORE MOIST AIRMASS FROM THE SOUTHWEST. THE RESULT WILL BE A SLOW
MODERATION OF TEMPERATURES THROUGH THE REST OF THE WEEK...FOLLOWED
BY CHANCES FOR SNOW LATE THIS WEEKEND AND EARLY NEXT WEEK.
WEDNESDAY NIGHT THROUGH SATURDAY...
PRIMARY FORECAST CHALLENGE IN THIS STRETCH WILL BE EARLY ON AS A NEW
ARCTIC AIRMASS SURGES INTO THE AREA WITH WEDNESDAY AND THURSDAY
NIGHTS SEEING THE LOWEST TEMPERATURES. HOWEVER...THE DEEP EASTERN
TROUGH PATTERN WE HAVE SEEN LATELY WILL BE DEAMPLIFYING. THIS MAY
HELP BLUNT THE DROP IN TEMPERATURES. IT WILL STILL BE VERY COLD
AND A PORTION OF THE AREA...PRIMARILY IN NORTH CENTRAL
WISCONSIN...MAY REQUIRE WIND CHILL ADVISORIES. EACH NIGHT HAS
ISSUES THOUGH. A SHORTWAVE WILL BE PASSING RELATIVELY NEAR THE
AREA WEDNESDAY NIGHT...AND THOUGH IT HAS APPEARED FOR SOME TIME
THAT IT WILL PASS WELL TO OUR SOUTH...GUIDANCE HAS DRIFTED NORTH
TODAY. IT IS POSSIBLE THAT FURTHER DRIFT MAY RESULT IN MORE
CLOUDINESS WHICH WOULD HELP ARREST THE FALL OF TEMPERATURES. ON
THURSDAY NIGHT...COLD TEMPERATURES WILL BE DRIVEN LARGELY BY THE
POTENTIAL FOR STRONG RADIATIONAL COOLING. BUT JUST HOW LOW WE GO
WILL DEPEND ON CLOUD COVER AND WHETHER OR NOT WINDS WILL BE CALM
OVERNIGHT...BOTH DIFFICULT THINGS TO FORECAST AT THIS RANGE. AFTER
THESE NIGHTS...THE AFOREMENTIONED PATTERN CHANGE SHOULD ENCOURAGE
A MODERATION OF TEMPERATURES FOR THE REST OF THE WEEK...THOUGH WE
ARE ONLY LOOKING TO AN INCREASE TO A LITTLE BELOW NORMAL FROM WELL
BELOW NORMAL.
ADDITIONALLY...THERE IS A SLIGHTLY INCREASED AREA OF OPEN WATER ON
LAKES SUPERIOR AND MICHIGAN AFTER RECENT GUSTY WINDS. THOUGH THE
WATER IS SURELY COLD...THE AIR MASS WILL BE COLDER AND WITH SOME
ONSHORE WIND TRAJECTORIES WEDNESDAY NIGHT...LAKE EFFECT FLURRIES
ARE NOT IMPOSSIBLE FOR THE VILAS COUNTY SNOW BELT AND PORTIONS OF
THE LAKE MICHIGAN SHORELINE IN EAST CENTRAL WISCONSIN...PARTICULARLY
THE BIT OF MANITOWOC COUNTY THAT JUTS OUT INTO THE LAKE AT
DIFFERENT ANGLE THAN THE REST OF THE SHORELINE.
SATURDAY NIGHT THROUGH TUESDAY...
WITH MORE SOUTHWEST FLOW ALOFT...A MID-LEVEL SHORTWAVE AND A WEAK
SURFACE LOW REFLECTION WILL BRING A CHANCE FOR SNOW TO THE AREA IN
THE SECOND HALF OF THE WEEKEND. AFTER A LARGE JUMP NORTH IN THE
MODEL GUIDANCE YESTERDAY THE ENVELOPE HAS SETTLED BACK TO THE
SOUTH A LITTLE BIT TODAY. THOUGH AT FIRST GLANCE IT APPEARS LIKE
THE AREA MAY STILL SEE A FAIR SHOT FOR SOME SYNOPTIC LIFT...A
DEEPER INVESTIGATION REVEALED LESS POTENTIAL THAN IT FIRST SEEMED.
STILL...THE WARMER AND MOISTER ADVECTION FROM THE SOUTHWEST MAKES
THE IDEA OF AT LEAST A LITTLE SNOW REASONABLE...PARTICULARLY IN
CENTRAL AND EAST CENTRAL WISCONSIN. IN THIS SCENARIO...IT WOULD BE
APPROPRIATE TO EXPECT SNOW TOTALS OF AROUND TWO INCHES OR LESS. A
COLD FRONT ASSOCIATED WITH A LOW AND ITS ATTENDANT SHORTWAVE IN
THE NORTHERN STREAM WILL SHIFT WINDS TO NORTHWESTERLY AND CUT OFF
THE SNOW. FORTUNATELY THE MORE ZONAL FLOW LOOKS TO PREVENT A
STRONG SURGE OF COLD AIR TO CHOP DOWN TEMPERATURES BEHIND THE
FRONT AT THIS TIME.
HOWEVER...AFTER ALL THIS TALK...IT IS IMPORTANT TO REMEMBER THAT
IT IS ONLY TUESDAY. THOUGH A BROAD SCENARIO IS PRESENT IN ALL THE
GUIDANCE AND CONFIDENCE IN THAT IS MODERATE TO HIGH...CONFIDENCE
IN THE DETAILS THIS FAR OUT IS RELATIVELY LOW...AND COULD HAVE
SIGNIFICANT INFLUENCES ON THE SENSIBLE WEATHER WITH THIS FEATURE.
IT WOULD NOT BE WISE TO RULE OUT A SOUTHERN MISS NOR HIGHER
SNOWFALL POTENTIAL FROM A NORTHWARD DEVIATION JUST YET.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 529 PM CST TUE FEB 24 2015
ARCTIC COLD FRONT WILL SWEEP ACROSS THE REGION THIS EVENING...BRINGING
MUCH COLDER AIR AND DIMINISHING WINDS THIS EVENING. VFR CONDITIONS WILL
PREVAIL ACROSS MUCH OF THE REGION...EXCEPT ACROSS THE FAR NORTH THIS
EVENING WHERE SOME PATCHY MVFR/IFR CIGS ARE POSSIBLE IN LIGHT SNOW
SHOWERS OR FLURRIES. ADDED A 2 HOUR WINDOW FOR LIGHT SNOW IN THE 00Z
KRHI TAF FROM 00Z-02Z BASED ON SURFACE OBSERVATIONS ACROSS NORTHERN
WISCONSIN. VFR CONDITIONS WILL CONTINUE ON WEDNESDAY WITH NORTHWEST
TO NORTH WINDS OF 5 TO 10 KNOTS. WINDS AT KGRB/KATW MAY TURN TO THE
NORTHEAST WEDNESDAY AFTERNOON.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......LUCHS
AVIATION.......ECKBERG
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 253 PM CST MON FEB 23 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE SETTLING OVER THE MID-MISSISSIPPI VALLEY AND EXTENDING
ACROSS THE EASTERN GREAT LAKES. CLEAR SKIES REMAIN ACROSS MOST OF
THE REGION EARLY THIS AFTERNOON WITH WIND CHILLS WARMING INTO THE 5
TO 15 BELOW RANGE. CLOUDS ARE INCREASING OVER THE NORTHERN PLAINS
AHEAD OF A SHORTWAVE DIVING SOUTHEAST OVER LAKE WINNIPEG. LIGHT
SNOW AND BLOWING SNOW ARE OCCURRING AHEAD OF THIS SHORTWAVE BUT
THESE ARE OCCURRING MAINLY NORTH OF THE BORDER. SOME WIND GUSTS ARE
REACHING BETWEEN 30 AND 35 KNOTS. AS THIS SHORTWAVE AND A MORE
POTENT WAVE BEHIND IT MOVING INTO THE REGION...SNOWFALL POTENTIAL
AND IMPACTS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...LEAD SHORTWAVE TROUGH OVER THE LAKE WINNIPEG REGION WILL
WEAKEN AS IT MOVES INTO THE REGION THIS EVENING. THE ARCTIC AIRMASS
AHEAD OF THIS WAVE IS VERY DRY...WHICH SHOULD KEEP THE AREA
PRECIP-FREE THROUGH THE EVENING. THEN AS A SECONDARY AND STRONGER
SHORTWAVE ARRIVES LATE TONIGHT...STRONG FORCING SHOULD PUSH AN AREA
OF LIGHT SNOW ACROSS THE REGION FROM NORTHWEST TO
SOUTHEAST...POSSIBLY MAKING IT INTO THE FOX VALLEY BY 12Z. ALTHOUGH
ACCUMULATIONS ARE EXPECTED TO REMAIN UNDER AN INCH...GUSTY SOUTHWEST
WINDS AHEAD OF THE SHORTWAVE WILL LEAD TO BLOWING AND DRIFTING SNOW
IN THE OPEN COUNTRY. THE CLOUDS AND WIND WILL PREVENT TEMPS FROM
FALLING MUCH TONIGHT...AND WILL GO WITH LOWS IN THE MIDDLE SINGLE
DIGITS ABOVE ZERO. WIND CHILLS WILL CONTINUE TO RANGE FROM 10 TO 20
BELOW THIS EVENING...THEN WARM AS TEMPERATURES RISE OVERNIGHT.
TUESDAY...THE LIGHT SNOW WILL CONTINUE TO SPREAD ACROSS THE FOX
VALLEY AND LAKESHORE AREAS EARLY IN THE MORNING BEFORE EXITING LATE
IN THE MORNING. MID-LEVEL MOISTURE PEELS OUT BEHIND THE SHORTWAVE
DURING THE AFTERNOON...BUT STEEPENING LOW LEVEL LAPSE RATES WITHIN A
BROKEN CLOUD DECK COULD YIELD SCATTERED FLURRIES. ADDITIONAL
ACCUMULATIONS COULD REACH UP TO A HALF INCH. GUSTY SOUTHWEST WINDS
IN THE MORNING WILL TURN TO THE WEST AND THEN NORTHWEST IN THE
AFTERNOON AND WILL PROMOTE BLOWING AND DRIFTING SNOW. WIND
TRAJECTORIES WILL BE PARALLEL TO DOOR COUNTY INITIALLY...BUT AS
WINDS VEER TO THE WEST AND THEN NORTHWEST...BLOWING AND DRIFTING
SNOW WILL INCREASINGLY BECOME A HAZARD TO THE WESTERN HALF OF THE
COUNTY EVEN AS WINDS SUBSIDE SOMEWHAT WITH THE APPROACH OF A SURFACE
TROUGH. SOME DISCUSSION WHETHER DOOR COUNTY WILL NEED A SNOW AND
BLOWING SNOW ADVISORY FOR TOMORROW. THINK WINDS WILL BE SOUTHWEST
THROUGH MOST OF THE SNOW FALL TOMORROW MORNING AND AM UNCERTAIN HOW
CONDITIONS WILL BE AFTER SEVERAL HOURS OF BLOWING/DRIFTING SNOW
PRIOR TO THIS. WILL ISSUE AN SPS HIGHLIGHTING THIS HAZARD.
TEMPERATURES WILL BE THE WARMEST IN SEVERAL DAYS...AND RANGE FROM
THE LOWER 20S TO LOWER 30S.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 253 PM CST MON FEB 23 2015
A BIT OF A CHANGE IN THE UPPER FLOW PATTERN IS IN THE
OFFING...WITH THE WESTERN RIDGE DRIFTING WEST OVER THE PACIFIC AND
A CUT OFF LOW DEVELOPING OVER THE SOUTHWEST...SETTING UP SOMETHING
MORE AKIN TO A SPLIT FLOW PATTERN AS THE WEEK GROWS LATE. THE
NORTHERN STREAM STILL HOLDS SIGNIFICANT SWAY IN OUR AREA
UNFORTUNATELY...AND THE IMPACT ON SENSIBLE WEATHER IS UNLIKELY TO
BE SIGNIFICANT UNTIL LATE THIS WEEKEND OR EARLY NEXT WEEK.
SATELLITE IMAGERY INDICATES A PATCH OF SOMEWHAT OPEN WATERS ON
LAKE SUPERIOR ALONG A LAKE EFFECT FETCH FOR NORTH CENTRAL
WISCONSIN...AND BREEZY SOUTHWEST WINDS IN THE SHORT TERM SHOULD
KEEP THAT AREA FROM FREEZING OVER. THIS LEAVES POTENTIAL FOR
LINGERING LAKE EFFECT FLURRIES OR SNOW SHOWERS TUESDAY NIGHT
IN THE NORTH CENTRAL SNOW BELT...THOUGH ACCUMULATIONS SHOULD BE
SLIGHT TO NIL. GUSTY WINDS WILL BE DIMINISHING THROUGH THE EVENING
HOURS AS THE PRESSURE GRADIENT LOOSENS...BRINGING AN END TO
POTENTIAL FOR BLOWING SNOW.
ANOTHER BEEFY HIGH WILL FOLLOW IN TO GIVE US ANOTHER PLUNGE IN
TEMPERATURES...BUT BEFORE THAT A SHORTWAVE WILL SHOOT THROUGH
THE UPPER TROUGH. THE GEM STUBBORNLY BRINGS FLURRIES OR EXTREMELY
LIGHT ACCUMULATIONS TO PORTIONS OF CENTRAL AND EAST CENTRAL
WISCONSIN. THE REST OF THE GUIDANCE SHUNTS EVERYTHING WELL SOUTH
OF THE AREA...AND THE FORECAST JOINS THAT CAMP IN KEEPING THINGS
DRY HERE.
THE MAIN STORY FOR THE SECOND HALF OF THE WORK WEEK...AGAIN...WILL
BE SIGNIFICANTLY BELOW NORMAL TEMPS. THE COLD AIR REACHES ITS
NADIR WEDNESDAY AFTERNOON INTO THURSDAY. HIGHS IN THE SINGLE
DIGITS TO LOW/MID TEENS ARE EXPECTED WITH LOWS BELOW ZERO. WIND
CHILL ADVISORIES MAY RETURN FOR ANOTHER SEQUEL...BUT THIS COLD
PUSH DOES NOT LOOK TO MATCH PREVIOUS ITERATIONS...SO THERE IS LESS
CONFIDENCE IN THAT AT THIS TIME. THE ARCTIC AIR MASS BEGINS TO
MODERATE ON FRIDAY AND ESPECIALLY THIS WEEKEND...BUT TEMPERATURES
STILL LOOK TO REMAIN BELOW NORMAL.
HEADING INTO THE WEEKEND...AS A TROUGH DIGS OVER THE WEST COAST
AND THE FLOW ALOFT BECOMES SOUTHWESTERLY. THIS FLOW WILL PUSH IN A
SLUG OF MOISTURE FROM THE SOUTHERN PLAINS FOR THE SECOND HALF OF
THE WEEKEND. MODELS ARE IN AGREEMENT SHOWING THE MOISTURE AND
PUSH OF WARMER AIR. HOWEVER...THERE IS SPREAD IN HOW FAR NORTH
THIS AIR GETS...WITH SIGNIFICANT IMPACTS ON SNOW POTENTIAL. THE
CANADIAN HOLDS COLD AIR OVER THE GREAT LAKES AND SENDS YET ANOTHER
WINTER STORM THROUGH THE MID-SOUTH AND FAR AWAY FROM OUR AREA. THE
GFS AND ECMWF ARE MORE READY TO BRING A MORE SIGNIFICANT SYSTEM
TOWARDS THE GREAT LAKES. AT THIS TIME IT AGAIN APPEARS THAT THE
HIGHEST SNOWFALL TOTALS WILL MISS THE AREA. HOWEVER...IT IS
POSSIBLE...GIVENT THE CURRENT GUIDANCE ENVELOPE...FOR ENOUGH
SNOWFALL TO MEET ADVISORY CRITERIA IN CENTRAL AND EAST CENTRAL
WISCONSIN. ULTIMATELY...THE MODEL SOLUTIONS ARE RELATIVELY FRAGILE
THIS FAR OUT...AND THE BEST ADVICE IS TO FOLLOW UPDATED FORECASTS
AS THE WEEK CONTINUES.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1134 AM CST MON FEB 23 2015
VFR CLEAR EXPECTED THROUGH THE EVENING AS CIRRUS SPREADS
ACROSS THE REGION AHEAD OF THE NEXT CLIPPER. SOUTHWEST WINDS WILL
INCREASE THROUGH THE AFTERNOON AND BECOME STRONG ENOUGH TO PRODUCE
BLOWING AND DRIFTING SNOW THIS EVENING THROUGH TUESDAY MORNING.
LIGHT SNOW WILL ARRIVE FROM NORTHWEST TO SOUTHEAST LATE TONIGHT AND
CONTINUE THROUGH MIDDAY TUESDAY BEFORE DIMINISHING/EXITING. THOUGH
THE SNOW WILL LIKELY DROP VSBYS TO IFR FOR A TIME...SNOW AMOUNTS
SHOULD BE AROUND AN INCH OR LESS IN MOST PLACES. LOW LEVEL WIND
SHEAR POSSIBLE TONIGHT WITH GUSTY SOUTHWEST SURFACE WINDS AND
SOUTHWEST WINDS OF 40 KNOTS AT 1200 FT AGL.
FIELD CREWS MAY BE NEEDED TO CLEAR SNOW DRIFTS FROM
RUNWAYS, TAXIWAYS AND RAMPS TONIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......LUCHS
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1130 PM CST SUN FEB 22 2015
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 231 PM CST SUN FEB 22 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE DRIFTING SOUTHEAST OVER THE NORTHERN GREAT PLAINS EARLY
THIS AFTERNOON. THOUGH COLD ADVECTION IS ONGOING...HEATING HAS
SERVED TO STEEPEN LOW LEVEL LAPSE RATES...WHICH TRIGGERED A CU FIELD
TO FORM LATE IN THE MORNING. DRY AIR IS WINNING OUT THIS AFTERNOON
AS EVIDENT BY THE CU FIELD DIMINISHING. ONLY CLEAR AND BITTERLY
COLD CONDITIONS EXIST UPSTREAM...SO FORECAST CONCERNS INCLUDE TEMPS
AND WIND CHILLS THROUGH MONDAY.
TONIGHT...STRONG ARCTIC HIGH PRESSURE WILL BE SLIDING SOUTHEAST FROM
THE NORTHERN GREAT PLAINS TO CENTRAL IOWA. LOSS OF DIURNAL HEATING
WILL CAUSE ANY LINGERING CU TO DISSIPATE BY EARLY THIS
EVENING...WHICH WILL LEAVE CLEAR SKIES FOR MUCH OF THE NIGHT.
BECAUSE THE ARCTIC HIGH WILL DROP SOUTHWEST OF THE REGION...BOTH
STATISTICAL AND NUMERICAL GUIDANCE POINT TOWARDS WINDS REMAINING IN
THE 5 TO 10 KT RANGE THIS EVENING...BEFORE DIMINISHING SOME
OVERNIGHT. SOME POTENTIAL FOR DECOUPLING OVER N-C WISCONSIN AS
BOUNDARY LAYER WINDS LIGHTEN. AS A RESULT...THINK TEMPERATURES HAVE
A CHANCE TO TUMBLE LATE TONIGHT. THIS MAKES FOR A DILEMMA IN TERMS
OF HEADLINE DECISIONS. IF WINDS REMAIN IN THE 4-5 KT RANGE...SOME
PLACES LIKE ANTIGO AND RHINELANDER COULD REACH WIND CHILL WARNING
CRITERIA FOR A PERIOD LATE TONIGHT INTO MONDAY MORNING. THINK
WARNING CONDITIONS WILL NOT BE WIDESPREAD ENOUGH DUE TO WINDS
DROPPING OFF. SO WILL STICK WITH THE ADVISORY THROUGH THE NIGHT AND
CONTINUE TO MENTION THAT SOME SPOTS WILL HIT WARNING CRITERIA. IF
WINDS DO DROP OFF...TEMPS 25 TO 30 BELOW ARE POSSIBLE.
MONDAY...HIGH PRESSURE WILL BE DRIFTING TO THE MID-MISSISSIPPI
VALLEY WHILE THE NEXT CLIPPER WILL REACH NORTHERN MINNESOTA LATE IN
THE AFTERNOON. A TIGHTENING PRESSURE GRADIENT BETWEEN THESE
FEATURES WILL CAUSE WINDS TO SWING AROUND TO THE SOUTHWEST AND
BECOME GUSTY IN THE AFTERNOON. BUT THE SOUTHWEST WINDS WILL ALSO
HELP MODERATE THE BITTERLY COLD AIRMASS. WIND CHILLS WILL BE
WARMING ABOVE ADVISORY CRITERIA BY LATE IN THE MORNING SO THE ENDING
TIME LOOKS ABOUT RIGHT. THOUGH CIRRUS WILL BE INCREASING IN THE
AFTERNOON...HIGHS WILL WARM INTO THE UPPER SINGLE DIGITS TO THE
LOWER TEENS.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 231 PM CST SUN FEB 22 2015
OVERALL UPPER LEVEL PATTERN CONSISTING OF A WESTERN RIDGE AND
EASTERN TROUGH WILL REMAIN FOR MOST OF THE PERIOD...ALTHOUGH THERE
ARE HINTS THAT THE WESTERN RIDGE MAY REORGANIZE FURTHER WEST OVER
THE PACIFIC WHILE FLOW OVER THE UNITED STATES TAKES ON MORE OF AN
APPEARANCE OF SPLIT FLOW. THIS CHANGE DOES NOT LOOK LIKE IT WILL
DO MUCH TO REVERSE OUR TREND OF SEEING TEMPS WELL BELOW
NORMAL. FOR NOW...ONLY TUESDAY LOOKS TO SEE HIGHS RELATIVELY NEAR
NORMAL...WITH A RETURN TO COLD WEATHER AFTER A FRONT MOVES
THROUGH.
THE PRIMARY CHANCE FOR MEASURABLE SNOW LOOKS TO BE MONDAY NIGHT
AND TUESDAY AS A LOW PRESSURE PASSES NORTH THROUGH ONTARIO...WITH
AN ATTACHED COLD FRONT PUSHING ACROSS THE AREA ONCE AGAIN. GUIDANCE
CONTINUES TO LIKE OUR FAR NORTH FOR THE BEST CHANCE AND AMOUNTS OF
SNOW...TO BE EXPECTED AS THE LOW PASSES SOME DISTANCE TO OUR NORTH
AND EAST. HOWEVER...THE GFS AND TO SOME EXTENT THE GEM PROVIDE
BETTER MOISTURE AND LIFT...AND BRING AN INCH OR TWO OF SNOW DOWN
THROUGH A LARGE PORTION OF THE NORTHEAST QUARTER OF WISCONSIN. IT
IS WORTH NOTING THAT THE GFS ENSEMBLE CONTINUES TO NOT BE AS
ENAMORED OF THIS IDEA AS THE DETERMINISTIC RUN. IN GENERAL WILL
FOLLOW SUIT...PUTTING THE HIGHEST POPS AND ACCUMULATIONS IN FAR
NORTHERN WISCONSIN...BUT WILL PAY SOME DEFERENCE TO THE NORTH
AMERICAN MODELS AND THEIR PLAUSIBLE...IF NOT AS CONVINCING...IDEA
OF MORE SNOW FURTHER TO THE SOUTH AND WEST WITH CHANCE POPS
TUESDAY MORNING.
ALONG WITH THIS SNOW...OUR POSITION BETWEEN THIS ONCOMING
LOW AND THE HIGH RESPONSIBLE FOR OUR MOST RECENT COLD PLUNGE WILL
RESULT IN GUSTY SOUTHWEST WINDS MONDAY NIGHT INTO TUESDAY. THIS
COULD CREATE SOME BLOWING AND DRIFTING OF ANY SNOW THAT MAY
FALL...EVEN IF AMOUNTS ARE NOT PARTICULARLY HIGH. GUIDANCE IS
UNANIMOUS IN STRONG 50 TO 65 KNOT WINDS AT RELATIVELY LOW ALTITUDE
VERY EARLY TUESDAY MORNING. SOUNDINGS IN BUFKIT SHOW POTENTIAL
GUSTS TO 20-30 KTS...AND GUSTS EVEN A LITTLE HIGHER ARE NOT OUT OF
THE QUESTION...THOUGH THIS SCENARIO WOULD NEED BETTER MIXING TO
COME TO FRUITION.
AFTERWARDS...HIGH PRESSURE SETTLES OVER THE AREA BRINGING DRY
WEATHER THROUGH SATURDAY. IN WHAT SURELY IS BEGINNING TO SOUND ALL
TOO FAMILIAR...WE WILL SEE ANOTHER SHOT OF WELL BELOW NORMAL
TEMPERATURES. THE COLDEST PERIOD LOOKS TO BE TUESDAY NIGHT THROUGH
THURSDAY. HIGHS ON WEDNESDAY LOOK TO BE MIRED IN THE SINGLE DIGITS
FOR MOST...WITH SUBZERO LOWS ON TAP TUESDAY AND WEDNESDAY NIGHT.
A SLOW MODERATION IN TEMPERATURES IS EXPECTED THROUGH THE WEEKEND.
ANOTHER CHANCE FOR PRECIPITATION EMERGES DURING THE WEEKEND...BUT
WITH A GOOD BIT OF UNCERTAINTY IN THE NATURE OF THE UPPER
FLOW...WILL NOT SPECULATE ON THE DETAILS FOR NOW.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1130 PM CST SUN FEB 22 2015
VFR CONDITIONS TO PREVAIL TNGT THRU MON EVENING AS A LARGE AREA
OF HI PRES MOVES FROM THE NRN PLAINS SE TOWARD THE OHIO RIVER
VALLEY. WINDS ARE FCST TO SLOWLY BACK FROM W-NW OVRNGT...TO WEST
MON MORNING...TO SW MON AFTERNOON. THE PRES GRADIENT WL GRADUALLY
TIGHTEN MON AFTERNOON BETWEEN THE HI PRES TO OUR SOUTH AND AN
AREA OF LOW PRES RESIDING WELL TO OUR NORTH. WIND GUSTS COULD
APPROACH 20 KTS BY LATE MON AFTERNOON AND 25 KTS MON EVENING. NE
WI WL ALSO SEE AN INCREASE IN HI CLOUDS MON AFTERNOON WITH MID
CLOUDS ARRIVING MON EVENING AHEAD OF A CDFNT THAT IS FCST TO MOVE
THRU THE AREA ON TUE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 10 AM CST MONDAY FOR WIZ005-010>013-
018>022-030-031-035>040-045-048>050-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......LUCHS
AVIATION.......AK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
403 AM CST WED FEB 25 2015
.SYNOPSIS...
ISSUED AT 330 AM CST WED FEB 25 2015
AT 330 AM...MID LEVEL CLOUDS WERE STREAMING INTO THE AREA AHEAD OF
A ROBUST CLIPPER SYSTEM. SNOW WAS CONTINUING TO DEVELOP ACROSS
PARTS OF SOUTH DAKOTA AND SOUTHWEST MINNESOTA. EARLY MORNING
TEMPERATURES WERE IN THE TEENS TO LOWER 20S AT MOST LOCATIONS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CST WED FEB 25 2015
THE MAIN FORECAST ISSUE IS THE IMPENDING POTENT CLIPPER SYSTEM AND
ASSOCIATED SNOWFALL AMOUNTS AND COVERAGE.
LOOKING AT THE VARIOUS SYNOPTIC AND HIGH RES MODELS...LATEST
TRENDS HAVE BEEN TOWARD HIGHER SNOWFALL AMOUNTS AND A SLIGHTLY
FARTHER NORTH AXIS OF THE HEAVIEST SNOW. THE INITIAL ISSUE IS
TIMING OF THE ONSET OF SNOW...DEPENDENT ON HOW THE DEFORMATION
ZONE/DRY SLOT SET UP. THE WRF IS A BIT FASTER IN BRINGING SNOW
INTO THE WEST THIS MORNING...WHILE THE RAP HAS A MORE PRONOUNCED
DRY SLOT EARLY IN THE EVENT. FOR PURPOSES OF THE FORECAST GRIDS
AND HEADLINES...HAVE GONE WITH THE EARLIER TIMING...WHICH CAN BE
ADJUSTED THROUGH THE DAY.
GIVEN THE STRENGTH AND DEPTH OF THE FORCING THROUGH THE DENDRITIC
LAYER...THE HIGHER SNOWFALL AMOUNTS LOOK REASONABLE BASED ON
AVERAGE SNOW RATIOS THROUGH THE BULK OF THE EVENT IN THE 14-19:1
RANGE. ALSO FAVORED CONSENSUS QPF...WHICH IS SLIGHTLY HIGHER TO
THE NORTH THAN WPC VALUES. THE END RESULT IS ROUGHLY 6-9 INCHES
FROM INDEPENDENCE...TO WAPELLO...FORT MADISON AND POINTS EAST.
HAVE UPGRADED THESE AREAS TO A WINTER STORM WARNING. FROM
DUBUQUE...THROUGH THE QUAD CITIES...WEST CENTRAL ILLINOIS...AND
FAR NORTHEAST MISSOURI...EXPECTING GENERAL 3-6 INCH AMOUNTS WITH A
WINTER WEATHER ADVISORY IN EFFECT. LOCALLY ENHANCED HIGHER SNOWFALL
AMOUNTS ARE NOT OUT OF THE QUESTION IN THE ADVISORY AREA.
ADJUSTMENTS TO SNOWFALL AMOUNTS/HEADLINES ARE INEVITABLE AS WE
HEAD THROUGH THE DAY AND INTO THIS EVENING.
PEAK SNOWFALL INTENSITY EXPECTED IN THE AFTERNOON/EVENING...WHICH
WILL MAKE FOR A HAZARDOUS COMMUTE WITH SNOW COVERED ROADS AND
REDUCED VISIBILITY. A NORTHWEST WIND AROUND 15 MPH WITH HIGHER
GUSTS WILL LIKELY PRODUCE SOME SHALLOW DRIFTING SNOW AT TIMES. THE
SNOW WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST LATE TONIGHT INTO
THURSDAY MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 330 AM CST WED FEB 25 2015
THURSDAY AND FRIDAY...VERY COLD PERIOD AS ARCTIC ~1042 MB HIGH
BUILDS INTO THE MIDWEST. FRESH POWDERY SNOW ON THE GROUND/LIGHT
WINDS (POSSIBLY DECOUPLED AT TIMES)/AND MAINLY CLEAR SKIES WILL SET
THE STAGE FOR VERY COLD OVERNIGHT LOWS. CURRENT FORECAST FAVORS THE
RAW GFS/ECMWF AS SUPERBLEND/NAM SEEM TO BE TOO WARM.
EXPECT WIDESPREAD LOWS BETWEEN -10 TO -15 F WHICH WOULD BE NEAR
RECORD TERRITORY FOR LATE FEBRUARY...SINGLE DIGIT SUB-ZERO LOWS ARE
MORE LIKELY SOUTH OF BURLINGTON. WINDS WILL REMAIN ON THE LIGHT SIDE
BUT EVEN AT 5-7 KTS THEY WILL BE ENOUGH TO CREATE DANGEROUS WIND
CHILLS BETWEEN -20 TO -30 F AT TIMES. VALUES NEAR -30 F SHOULD BE
RELATIVELY ISOLATED AND SHORT-LIVED. HIGHS ARE FORECAST TO BE IN THE
UPPER SINGLE DIGITS TO MID TEENS.
SATURDAY AND SUNDAY...SIGNIFICANT PATTERN CHANGE WILL OCCUR DURING
THIS TIME AS UPPER JET DIGS OUT A LARGE TROUGH OVER THE WESTERN U.S.
WHICH WILL CAUSE A BIG SHIFT IN THE ORIENTATION OF THE 850 MB
BAROCLINIC ZONE TO A SW-NE DIRECTION.
THERE HAS BEEN A CONSISTENT SIGNAL OF SIGNIFICANT LOW/MID LEVEL
MOISTURE ADVECTION FROM THE SW U.S. AND FROM THE GULF OF MEXICO FOR
SAT NIGHT INTO SUN. THEREFORE...A PERIOD OF SNOW IS LIKELY WITH
AMOUNTS UNCERTAIN THIS FAR OUT. WITH THE LACK OF A STRONG SHORTWAVE
TROUGH/VORTICITY MAX...MODELS DEVELOP LINEAR-LOOKING FRONTAL PRECIP
AND DO NOT DEVELOP A COHERENT SFC LOW WHICH WOULD PUT SOMEWHAT OF A
LIMIT ON THIS SYSTEM. DAYTIME TEMPS WILL BE IN THE 20S ON SAT AND
THE UPPER 20S TO LOWER 30S ON SUN.
MONDAY AND TUESDAY...CHANCE OF PRECIP MORE LIKELY LATER IN THE DAY
AND INTO TUE. MODELS STILL STRUGGLING WITH WHEN TO EJECT ORGANIZED
500 MB VORTICITY MAX OUT OF THE FOUR CORNERS AREA. THE GFS HAS A
WELL ORGANIZED SFC LOW TRACKING FROM OKLAHOMA TO NORTHERN INDIANA
WHICH IS FAVORABLE FOR WIDESPREAD PRECIP IN THE DVN CWA. WARMER AIR
ALOFT MAY MAKE IT FAR ENOUGH NORTH TO BRING VARYING PRECIP TYPES TO
PORTIONS OF THE FORECAST AREA. STAY TUNED. EARLY LOOK AT FORECAST
HIGHS ARE IN THE UPPER 20S TO MIDDLE 30S ON TUE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1138 PM CST TUE FEB 24 2015
A WINTER STORM SYSTEM DEVELOPING OVER THE NORTHERN PLAINS WILL
SPREAD SNOW ACROSS EASTERN IOWA AND NORTHWEST ILLINOIS WEDNESDAY
INTO WEDNESDAY NIGHT...RESULTING IN WIDESPREAD IFR TO LIFR
CONDITIONS. THROUGH THE REST OF TONIGHT INTO WEDNESDAY
MORNING...CONDITIONS WILL REMAIN VFR WITH LIGHT WINDS AND
INCREASING HIGH CLOUDS. SNOW AND LOWERING CIGS ARE EXPECTED TO
DEVELOP OVER CID BY MIDDAY AND REACH THE REST OF THE TERMINALS BY
MID AFTERNOON WITH WIDESPREAD IFR CONDITIONS BY LATE AFTERNOON.
ALL TERMINALS WILL HAVE THE POTENTIAL FOR LIFR OR EVEN VLIFR
PERIODS FROM LATE AFTERNOON INTO EARLY EVENING. WHILE NOT
ADVERTISED...SOME IMPROVEMENT IS POSSIBLE TOWARD LATE EVENING AT
CID AND DBQ AS THE SYSTEM BEGINS TO EXIT THE REGION.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST THURSDAY FOR
CLINTON-DELAWARE-DUBUQUE-JACKSON-JONES-SCOTT.
WINTER STORM WARNING FROM NOON TODAY TO 6 AM CST THURSDAY FOR
CEDAR-DES MOINES-HENRY IA-JEFFERSON-LEE-LOUISA-MUSCATINE-
VAN BUREN.
WINTER STORM WARNING FROM 9 AM THIS MORNING TO 3 AM CST THURSDAY
FOR BENTON-BUCHANAN-IOWA-JOHNSON-KEOKUK-LINN-WASHINGTON.
IL...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST THURSDAY FOR
HENRY IL-MERCER-ROCK ISLAND.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST
THURSDAY FOR HANCOCK-HENDERSON-MCDONOUGH-WARREN.
MO...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST
THURSDAY FOR CLARK-SCOTLAND.
&&
$$
SYNOPSIS...RP KINNEY
SHORT TERM...RP KINNEY
LONG TERM...UTTECH
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS GRAY ME
1207 AM EST WED FEB 25 2015
.SYNOPSIS...
WEAK LOW PRESSURE WILL PASS EAST OF THE AREA LATE TONIGHT AND
WEDNESDAY....AND WILL PRODUCE A PERIOD OF SNOW...ENDING BY
WEDNESDAY AFTERNOON. HIGH PRESSURE FOLLOWS THIS SYSTEM FOR
THURSDAY INTO THE START OF NEXT WEEKEND. THE NEXT CHANCE FOR
PRECIPITATION WILL COME AS HIGH PRESSURE RETREATS LATE IN THE
WEEKEND OR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1205 AM...MINOR ESTF UPDATE TO INGEST THE LATEST MESONET INTO 1ST
PERIOD GRIDS.
PREV DISC...
1040 PM UPDATE...VERY LITTLE CHANGE TO THE GOING FORECAST.
TIGHTENED UP THE EXPECTED SNOWFALL GRADIENT FOR THE OVERNIGHT. THIS
BASED ON LATEST FEW RUNS OF THE HRRR...RAP...AND 00Z NAM GUIDANCE
AS WELL AS REGIONAL RADAR IMAGERY. BUT I ADMIT IT IS GOING TO BE A
CLOSE CALL. ALMOST CERTAINLY A CASE OF THE HAVES AND HAVE NOTS
GIVEN THE EXPECTED SNOWFALL GRADIENT BASED ON LATEST RADAR IMAGERY
IN THE VICINITY OF EASTERN LONG ISLAND. RADAR WATCHING ACROSS
RI/SE MASS OVER THE COURSE OF THE NEXT TWO HOURS WILL BE THE KEY
TO UPDATING POPS/AMTS ASSOCIATED WITH THE WESTERN EDGE OF THE
SNOW SHIELD. WHOMEVER GETS IN IN IT MAY SNOW HEAVILY FOR AN HOUR
OR TWO...WITH GOOD ACCUMULATORS AS FAR AS SNOWFLAKE TYPES GO. WE
MAINLY EXPECT THIS POSSIBILITY NEAR AND EAST OF I-95.
930 PM UPDATE...NO CHANGES TO THE FORECAST AT THIS TIME.
AWAITING THE ARRIVAL OF THE 00Z RGEM AND NEW HRRR/RAP RUNS BEFORE
MAKING ANY CHANGES THE FORECAST THIS EVENING. WHILE RAPID UPDATE
MESOSCALE GUIDANCE LIKE THE HRRR AND RAP ARE STILL EAST WITH ANY
SNOWFALL...THE RADAR IMAGERY SOUTH OF LONG ISLAND NY SAYS PERHAPS
OTHERWISE. STILL EXPECTING THE MID COAST OF MAINE TO DO PRETTY
WELL OVERNIGHT...JUST NOT COMPLETELY SURE IF ACCUMULATING SNOW
MAKES AN APPRARANCE IN PSM AND PWM FOR EXAMPLE.
615 PM UPDATE...HAVE UPDATED THE NEAR TERM FORECAST BASED ON
LATEST TRENDS IN OBSERVATIONAL DATA AS WELL AS NEW MESOSCALE
MODEL DATA. IT WILL BE INTERESTING TO SEE HOW THE SNOWFALL PANS
OUT LATER TONIGHT. 18Z MODEL RUNS PRETTY MUCH STATUS QUO.
HOWEVER...LATEST FEW RUNS OF THE RAP AND HRRR KEEP MOST OF IT
OFFSHORE. HOPEFULLY THE TWO CAMPS WILL MERGE OVER THE NEXT COUPLE
OF HOURS.
PREVIOUSLY...
WEAK WAVES IN THE SRN AND NRN STREAM PASS TO OUR NW AND SE LATE
TONIGHT /BEFORE EVENTUALLY PHASING TO OUR EAST ON WED/ AND WILL
BRING A PERIOD OF LIGHT OR SHSN TO MOVE OVER THE REGION...MAINLY
AFTER MIDNIGHT. MODELS ARE IN GOOD AGREEMENT THAT AS THE SYSTEMS
INTERACT LATE TONIGHT WE WILL START TO SEE SOME MID LVL
FRONTOGENESIS FORM JUST OFFSHORE. THIS WILL LKLY FORM A BAND OF SNOW
OFF THE COAST...WHICH WILL GRAZE COASTAL AREAS E OF KPWM AND WILL
IMPACT THE MID COAST AND ESPECIALLY THE PENOBSCOT BAY REGION WITH 3
TO 6 INCHES OF SNOW. AS YOU MOVE FURTHER NW FROM THIS AREA AMTS DROP
OFF QUICKLY...WITH 1-3" FROM SEACOAST NH NE THROUGH THE PORTLAND
AREA...THE CAPITAL REGION...AND INTO SRN SOMERSET COUNTY. EXPECT AN
INCH OR LESS ACROSS THE REST OF NH AND INTERIOR WRN ME. THE BULK OF
THE SNOW LOOKS TO FALL BETWEEN 06Z AND 12Z. IN THE ADVISORY AREA IT
MAY LINGER UNTIL ABOUT 15Z...SO COULD SEE A QUICK 4-6" OF SNOW HERE
DURING PRE-DAWN AND INTO THE MORNING COMMUTE. TEMPS WILL DROP OFF A
BIT THIS EVENING...MORE SO IN THE ERN AND NRN ZONES WHERE LESS
CLOUDS AND A PERIOD WITHOUT ANY REAL BL FLOW WILL ALLOW SOME RAD
COOLING. BUT TEMPS HERE WILL STALL AND SHOULD BEGIN TO RISE NEAR THE
COAST AFTER MIDNIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
SOME LIGHT SNOW MAY LINGER OUTSIDE THE ADV AREA FOR THE EARLY
MORNING...BUT SHOULD BE CLOSE TO OVER BY 12Z...WITH THE EXCEPTION
OF THE ADVISED MID-COAST AREA...WHERE SNOW WILL LINGER THRU ABOUT
14-15Z. MODELS INDICATE RAPID CLEARING FROM W-E BEHIND THIS SYSTEM
AS W WINDS DOWNSLOPE AND DRIER AIR MOVES IN. WITH THE SUN AND THE
DOWNSLOPE...WILL SEE TEMPS RISE IN THE UPPER 20S TO LOWER 30S ON THE
COASTAL...AND INTO THE LOW TO MID 20S IN THE MTNS AND FOOTHILLS.
THE WINDS DIE OFF AROUND SUNSET WITH MAINLY CLEAR SKIES AND LIGHT
WINDS SHOULD SEE SOME GOOD RAD COOLING...BUT WITH WARMER AIR
ALOFT...WILL NOT BE AS COLD AS MON MORNING WITH LOWS SINGLE ABV ZERO
NEAR THE COAST...AND SINGLE DIGITS BELOW ZERO INLAND.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
LOW PRESSURE WILL MOVE
SOUTH OF THE REGION DURING THURSDAY. AT THIS POINT IT LOOKS LIKE
CLOUDS FROM THIS SYSTEM WILL CROSS THE AREA BUT THE PRECIPITATION
SHIELD WILL STAY SOUTH OF THE AREA. THE GFS WOULD GIVE THE
POSSIBILITY OF A FEW FLURRIES BUT THE EURO KEEPS ALL PRECIPITATION
SOUTH. REINFORCING COLD COMES IN BEHIND THIS SYSTEM FOR FRIDAY AND
SATURDAY AS HIGH PRESSURE BUILD OVER THE REGION.
FOR SUNDAY...AS THE HIGH MOVES EAST OF THE AREA CLOUDS WILL INCREASE
AND TEMPERATURES WILL MODERATE SOME. A WEAK OVERRUNNING SETUP FORMS
SUNDAY NIGHT THAT COULD PRODUCE A PERIOD OF SNOW. ANOTHER WEAK AREA
OF HIGH PRESSURE BRIEFLY BUILDS IN FOR MONDAY.
MODELS AGREE ON BRINGING ANOTHER AREA OF LOW PRESSURE OVER THE
AREA LATE MONDAY NIGHT AND TUESDAY. WITH MODERATING
TEMPERATURES...PRECIPITATION TYPE COULD BECOME A CHALLENGE BY LATE
TUESDAY OVER SOUTHERN AREAS.
&&
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM...CONDITIONS DETERIORATE TO MVFR LATE THIS EVENING AND
EVENTUALLY IFR IN -SN AT ALL BUT KLEB/KHIE WHERE IT WILL LKLY STAY
MAINLY MVFR IN -SHSN. CONDS WILL IMPROVE QUICKLY TO VFR DURING WED
MORNING BEHIND THIS SYSTEM...WHICH WILL PERSIST INTO WED NIGHT.
LONG TERM...AN AREA OF MVFR CLOUDS WILL BE POSSIBLE THURSDAY AS
LOW PRESSURE MOVES SOUTH OF THE REGION. HIGH PRESSURE WILL RESULT
IN MOSTLY VFR CONDITIONS FRIDAY AND SATURDAY. A WARM FRONT COULD
RESULT IN MVFR CONDITIONS ON SUNDAY AND SUNDAY NIGHT. A PERIOD OF
SNOW IS POSSIBLE SUNDAY NIGHT.
&&
.MARINE...
SHORT TERM...WILL SEE AN INCREASE IN SW FLOW...WHICH COULD PRODUCE
A FEW GUSTS TO NEAR 25 KT LATE TONIGHT...BUT WILL HOLD OFF THE SCA
FOR NOW. BETTER CHC FOR SCA WILL BE IN THE W FLOW BEHIND THE
SYSTEM FROM LATE WED MORNING INTO WED EVE.
LONG TERM...
LOW PRESSURE WILL PASS SOUTH OF THE WATERS THURSDAY. HIGH PRESSURE
WILL BUILD OVER THE WATERS FRIDAY AND SATURDAY FOLLOWED BY THE
APPROACH OF A WARM FRONT SUNDAY. WINDS AND WAVES ARE EXPECTED TO
REMAIN BELOW SCA LEVELS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MEZ022-
026>028.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 11 PM EST THIS
EVENING FOR ANZ151-153.
SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR ANZ150-
152-154.
&&
$$
ES
AREA FORECAST DISCUSSION
NWS HASTINGS NE
355 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST WED FEB 25 2015
...ARCTIC AIR RETURNS WITH A VENGEANCE WITH FRONTAL PASSAGE
ACCOMPANIED BY POSSIBLE RAIN/SNOW SHWRS FOLLOWED BY HOWLING N
WINDS UP TO 50 MPH...
ALOFT: SEVERAL WEAK/SUBTLE SHORTWAVE TROFS WILL CROSS THE FCST
AREA THRU TONIGHT IN NW FLOW. THE LEAD TROF WILL BE THE POTENTIAL
WX- MAKER WHICH WILL MOVE THRU 15Z-00Z...ASSOCIATED WITH THE
PASSAGE OF THE SFC LOW.
SURFACE: AN ARCTIC COLD FRONT EXTENDED FROM HUDSON BAY THRU THE
GREAT LAKES ACROSS IA TO LOW PRES OVER SD AND THEN NW INTO CANADA.
THIS LOW WILL HEAD SE ACROSS NEB TODAY AND IN ITS WAKE THE FRONT
WILL SURGE S TODAY AND WILL BE S OF THE FCST AREA BY SUNSET.
ARCTIC HIGH PRES THEN BEGINS BUILDING IN TONIGHT FROM CANADA.
EARLY THIS MORNING: CLOUDS WILL CONT TO INCREASE FROM THE NW.
GENERALLY MILD WITH TEMPS AT OR ABOVE FRZG MOST LOCATIONS.
HAZARDS: N WINDS WILL GUST 45-50 MPH 12PM-12AM. DANGEROUS WIND
CHILLS DOWN TO -20F LATE TONIGHT...N OF I-80.
TODAY: NOT SURE HOW IT UNFOLDS. WE KNOW FOR SURE THAT THE
STEADIEST PRECIP WILL BE E OF THE FCST AREA...ON THE COLD SIDE OF
THE FRONT IN THE WAA. SPOTTY ECHOES HAVE BEEN INCREASE THRU THE
NIGHT SW OF THE LOW THRU THE BLACK HILLS INTO THE PANHANDLE.
UPSTREAM SOUNDINGS SHOW A LOT OF DRY AIR IN THE LOW-LVLS. SO FAR
HAVE ONLY SEEN ONE STATION REPORT SPRINKLES UPSTREAM.
OVERALL EXPECT A M/CLOUDY DAY OVER S-CNTRL NEB AND BECOMING
M/CLOUDY OVER N-CNTRL KS. MOST MESOSCALE MODELS SUGGEST A
NARROW/BROKEN BAND OF STRONGLY-FORCED SHWRS WILL DEVELOP ALONG THE
FRONT WHICH COULD BRIEFLY CHANGEOVER TO SNOW BEFORE ENDING...
PRIMARILY N OF HWY 6. PRECIP WILL INITIALLY STRUGGLE TO REACH THE
GROUND. THE ENVIRONMENT IS NOT FAVORABLE FOR MUCH MEASURABLE
PRECIP.
THE LOWEST CONFIDENCE PORTION OF THE FCST IS TEMPS. WE COULD BE
TOO COOL. MULTIPLE OVERNIGHT CYCLES OF THE RAP SUGGEST 50F UP TO
I-80 AND NEARING 60 OVER N-CNTRL KS. I COULD ONLY ENVISION THAT
HAPPENING WITH FULL SUN AND THAT IS NOT EXPECTED. USED CONSENSUS
OF HI-RES SHORT-TERM MODELS FOR HIGHS AND THEN NUDGED HIGHS MORE
INTO THE 50S OVER N-CNTRL KS IN COORDINATION WITH KS OFFICES.
TEMPS WILL FALL THIS AFTERNOON N OF I-80 BEHIND THE FRONT.
WINDS: BLENDED THE 18Z/00Z MAV MOS 50-50. N WINDS WILL HOWL...
GUSTING 45-50 MPH IN THE TIGHT PRES GRADIENT/CAA BEHIND THE LOW. 6
HR PRES RISES OF 12 MB ARE LIKELY.
TONIGHT: CLOUDY...WINDY AND TURNING VERY COLD. WINDS WILL BE
STRONGEST PRIOR TO MIDNIGHT. TEMPS PLUMMET INTO THE SINGLE DIGITS
OVER N-CNTRL NEB AND LINGERING WINDS WILL PUSH WIND CHILLS AS LOW
AS -20F.
CAA WILL RESULT IN SOME MODEST INSTABILITY IN THE LINGERING
STRATUS WHICH WILL COOL INTO THE IDEAL SNOW GROWTH LAYER. SO KEPT
THE MENTION OF FLURRIES FROM THE PREVIOUS FCST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 354 AM CST WED FEB 25 2015
THIS SECTION WILL UPDATE SOON.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z WED NIGHT)
ISSUED AT 1159 PM CST TUE FEB 24 2015
REST OF TONIGHT: MULTI-LAYERED VFR MID-LVL CIGS WILL OVERTAKE THE
TERMINALS FROM THE N...REMAINING AT OR ABOVE 10K FT. SSW WINDS
JUST UNDER 10 KTS. THERE MAY BE SOME MARGINAL LLWS BASED ON WINDS
FROM OUR RADAR AT 400 FT...BUT THESE WINDS MAY BE OVERDONE.
CONFIDENCE: HIGH
TUE: VFR CIGS LOWER TO AROUND 3500 FT. COLD FRONT PASSES THE
TERMINALS AROUND 18Z WITH A BRIEF BURST OF POSSIBLY IFR SNOW.
THERE IS UNCERTAINTY IN THE INTENSITY OF THE SNOW. IF THE WORST
CASE OCCURS...ANY ACCUM WOULD BE LESS THAN 1 INCH. MVFR CIGS MOVE
IN AFTER FRONTAL PASSAGE AND N WIND WILL GUST TO 35 KTS...WITH A
ONE-TIME PKWND OF 40 KTS POSSIBLE. CONFIDENCE: MEDIUM
TUE EVE: MVFR CIGS REMAIN. N WINDS WILL BE GRADUALLY DECREASING.
CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...HEINLEIN
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
257 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 216 AM CST WED FEB 25 2015
INITIAL CONCERN WILL BE TYPE AND EXTENT OF PRECIP AS SURFACE LOW
TRACKS ACROSS THE AREA TODAY. THEN COLD AND WINDY CONDITIONS WITH
SUBZERO WIND CHILLS APPROACHING CRITERIA THURSDAY MORNING. JUST
PLAIN COLD FRIDAY MORNING.
SURFACE LOW WAS LOCATED OVER SOUTH CENTRAL SOUTH DAKOATA AT 08Z
WITH PRIMARY BAND OF PRECIP FROM EASTERN SOUTH DAKOTA INTO
SOUTHWEST MINNESOTA AND NORTHWEST IOWA. BOTH THE HRRR AND RAP
SLOWER IN BRINGING THE PRECIP SHIELD SOUTH TODAY WITH PRIMARY BAND
STRETCHING ACROSS NORTHERN IOWA THROUGH THE MORNING. HAVE ADJUSTED
TIMING OF THE WINTER WEATHER ADVISORY TO ACCOUNT FOR THIS FEATURE
AND ALSO REMOVED THE TWO SOUTHWEST IOWA COUNTIES AS TEMPERATURES
ARE EXPECTED TO REMAIN ON THE WARM SIDE THERE FOR MOST OF THE DAY
WITH BETTER QPF EAST OF THE AREA.
HAVE TRENDED TEMPERATURES WARMER ACROSS THE SOUTH HALF OF THE AREA
AND BACKED OFF FURTHER ON PRECIP AND SNOW ACROSS THE SOUTH.
TEMPERATURES WILL BE TRICKY TODAY AND DEPEND ON TIMING OF THE COLD
AIR BEHIND THE FRONT THIS AFTERNOON AS THE LOW TRACKS ACROSS EAST
CENTRAL NEBRASKA TOWARD NORTHWEST MISSOURI. A PERIOD OF MIXED
PRECIP...WHICH COULD INCLUDE FREEZING RAIN...IS POSSIBLE FOR A
TIME THIS MORNING IN PARTS OF NORTHEAST NEBRASKA INTO WEST CENTRAL
IOWA BEFORE THE COLD AIR MOVES IN BEHIND THE FRONT. AMOUNTS SHOULD
BE LIGHT WITH LIMITED AREAL COVERAGE.
THE ARCTIC AIR SPREADS RAPIDLY SOUTH TONIGHT ALONG WITH GUSTY
NORTHWEST WINDS. SUBZERO WIND CHILLS ARE LIKELY ACROSS THE AREA BY
THURSDAY MORNING WITH NORTHERN COUNTIES APPROACHING ADVISORY
CRITERIA. WILL COVER THE COLD IN HWO FOR NOW BUT ADVISORY LOOKS
LIKELY IN LATER FORECASTS. WINDY AND COLD CONDITIONS WILL EXTEND
THROUGH THE DAY ON THURSDAY WITH WINDS DIMINISHING THURSDAY
EVENING. TEMPERATURES ARE EXPECTED TO PLUNGE BELOW ZERO THURSDAY
NIGHT AS HIGH SETTLES OVER THE AREA AND WINDS BECOME LIGHT. SLOW
WARMING???? ON FRIDAY AS HIGH MOVES EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 216 AM CST WED FEB 25 2015
LITTLE CHANGE TO GENERAL TRENDS. WEEKEND SYSTEM STILL KEEPS MAIN
PRECIP AXIS TO THE SOUTH WITH LIGHTER AMOUNTS FOR THE SOUTH HALF
OF THE CWA. MORE SIGNIFICANT SNOW POSSIBLE MONDAY INTO TUESDAY AS
MAIN WAVE COMES INTO THE PLAINS REGION.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1120 PM CST TUE FEB 24 2015
VFR CONDITIONS ARE LIKELY TO CONTINUE OVERNIGHT. CONDITIONS WILL
DETERIORATE WEDNESDAY AND MIXED PCPN SHOULD DEVELOP. COLD AIR
MOVING IN WILL CHANGE THE PCPN TO SNOW...AND EXPECT THAT IFR
CONDITIONS WILL OCCUR WITH THE SNOW. WINDS WILL SHIFT FROM
SOUTHEAST TO THE NORTHEAST...THEN NORTH WITH GUSTS TO 39 KNOTS OR
MORE AFTER THE WIND SHIFTS TO NORTH. MVFR CEILINGS ARE LIKELY TO
CONTINUE WITH STRONG WINDS INTO WEDNESDAY EVENING.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 PM CST THIS
EVENING FOR NEZ015-034.
IA...WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 8 PM CST THIS
EVENING FOR IAZ055-056.
WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 PM CST THIS
EVENING FOR IAZ043.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 8 PM CST
THIS EVENING FOR IAZ069.
&&
$$
SHORT TERM...FOBERT
LONG TERM...FOBERT
AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
409 AM EST WED FEB 25 2015
.SYNOPSIS...
A STRENGTHENING LOW PRESSURE SYSTEM WILL MOVE OUT OF THE GULF OF
MEXICO TODAY...AND OFF THE SOUTH CAROLINA COAST TONIGHT. THIS WILL
BRING PERIODS OF RAIN TO THE AREA TONIGHT...WITH SOME SNOW
POSSIBLE WELL INLAND. THIS LOW PRESSURE WILL PULL AWAY ON
THURSDAY...LEAVING SOME LIGHT DRIZZLE OR FREEZING DRIZZLE THURSDAY
MORNING BEFORE CONDITIONS DRY OUT. A WEDGE OF HIGH PRESSURE WILL
BUILD DOWN THE COAST FRIDAY AND INTO THE WEEKEND BRINGING DRY BUT
COLD CONDITIONS. A WARMING TREND WILL DEVELOP NEXT WEEK ALONG WITH
INCREASING RAIN CHANCES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM TUESDAY...PRECIP IS COMPLETELY OFFSHORE AND CLOUDY
SKIES ARE ANTICIPATED TO CONTINUE OVERNIGHT. LATEST HIGH-RES
MODELS SHOW WITH THE LACK OF ADVECTION ACROSS SOUTH CAROLINA
TEMPERATURES MAY NOT FALL MUCH (IF ANY) OVERNIGHT. IN FACT WITH
TEMPERATURES NOW ABOVE FREEZING AT BOTH MYRTLE BEACH AND KINGSTREE
I AM NOT CERTAIN THERE`S MUCH CONCERN FOR ICE ON ROADS ACROSS SOME
PARTS OF NE SOUTH CAROLINA. I HAVE RE-WRITTEN THE SPECIAL WEATHER
STATEMENT TO FOCUS CONCERN ON SE NORTH CAROLINA WHERE WE ARE
SEEING REPORTS OF MULTIPLE CLOSED BRIDGES AND ELEVATED ROADS IN
WILMINGTON.
DISCUSSION FROM 645 PM FOLLOWS...
ITS BEEN A HECTIC FEW HOURS HERE. A BAND OF MODERATE FREEZING RAIN
THAT EXTENDED AS FAR WEST AS THE SC MIDLANDS EARLIER THIS
AFTERNOON IS FINALLY PUSHING OFF THE COAST NEAR CAPE FEAR THIS
EVENING. THIS PRECIPITATION FELL PRIMARILY ACROSS SE NORTH
CAROLINA WHERE AIR TEMPERATURES WERE IN THE 28-31
RANGE...PRODUCING LARGE AMOUNTS OF FREEZING RAIN BETWEEN 2-6 PM.
THE FREEZING RAIN SENSOR AT THE ILM (WILMINGTON) ASOS REPORTED
0.40 INCHES OF ICE ACCRETION TODAY. NORMALLY OUTPUT FROM THIS
SENSOR AGREES QUITE WELL WITH HUMAN-OBSERVED ACCRETION ON ELEVATED
OBJECTS AT THE NWS OFFICE...BUT THE ASOS SENSOR APPEARS TO HAVE
RUN A LITTLE HIGH WITH ITS TOTALS TODAY AS WE ARE ESTIMATING
CLOSER TO 0.25 INCHES OF ICE ACCRETION HERE. REPORTS RECEIVED VIA
FACEBOOK AND TWITTER CONFIRM WIDESPREAD 0.25 INCH ICE
ACCUMULATIONS AROUND THE CAPE FEAR AREA TODAY...VERIFYING THE ICE
STORM WARNING THAT WAS ISSUED EARLIER.
RADAR ECHOES ARE PUSHING OFFSHORE AT 40 KNOTS...HOWEVER ASOS/AWOS
OBSERVATIONS AND A PHONE CALL FROM THE NCDOT IN LUMBERTON EARLIER
CONFIRMS THAT A COUPLE HOURS OF FREEZING DRIZZLE CONTINUES BEHIND
THE RADAR-OBSERVED BACK EDGE OF THE PRECIP SHIELD. FOR THIS REASON
I WILL MAINTAIN THE WATCHES AND ADVISORIES UNTIL 8 PM EAST OF
I-95.
FOR THE REMAINDER OF THE OVERNIGHT PERIOD...IT APPEARS LOW CLOUDS
WILL HOLD TOUGH FOR ALL BUT PERHAPS THE LUMBERTON-BENNETTSVILLE
AREA WHERE SOME LIMITED CLEARING MAY DEVELOP LATE TONIGHT AS
MOISTURE THINS FROM ALOFT. THIS WILL PREVENT ANY SIGNIFICANT
RADIATIONAL COOLING AND LOWS SHOULD RANGE FROM 26-30...COOLEST
NEAR LUMBERTON AND WARMEST NEAR GEORGETOWN. THE 12Z & 18Z GFS
BOTH APPEAR TO BE UP THE SAME ANTICS PULLED DURING LAST WEEK`S
ARCTIC COLD WHERE IT SEVERELY OVERESTIMATES RADIATIONAL COOLING
POTENTIAL OVER MEAGER SNOWPACK ACROSS MUCH OF NORTH CAROLINA. THE
18Z NAM AND 22Z RUC LOOK MUCH MORE REASONABLE FOR TEMPERATURES
OVERNIGHT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM WEDNESDAY...BIGGEST CONCERN IN THE SHORT TERM INVOLVES
DEPARTING LOW PRESSURE THURSDAY...AND THE CHANCE FOR WINTRY PRECIP
ACROSS THE AREA.
CENTER OF STRENGTHENING LOW PRESSURE WILL BE OFF THE OUTER BANKS OF
NC TO START THURSDAY MORNING...AND WILL RAPIDLY PULL OFF TO THE
NORTHEAST THROUGH THURSDAY AFTN. ALTHOUGH THE MAJORITY OF THE
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL FALL ON
WEDNESDAY...LOW-LEVEL RESIDUAL MOISTURE BELOW 700MB WILL REMAIN INTO
THURSDAY EVENING. THIS OF COURSE WILL NOT PRODUCE HEAVY PRECIP...BUT
VERY LIGHT RAIN AND DRIZZLE...ALONG WITH WIDESPREAD LOW
CLOUDINESS...WILL PERSIST INTO THURSDAY NIGHT. THE QUESTION IS HOW
QUICKLY CAN SURFACE TEMPS FALL BELOW FREEZING DURING
THURSDAY...WHICH WOULD CREATE A FREEZING DRIZZLE SCENARIO. GUIDANCE
IS IN VERY GOOD AGREEMENT WITH TEMPS REMAINING JUST ABOVE FREEZING
NEAR THE COAST...BUT DROPPING TO BELOW INLAND. FORTUNATELY...THE
BETTER CHANCE FOR RESIDUAL PRECIP IS NEAR THE COAST...AND EVEN IN
THOSE PLACES THAT DO ENCOUNTER SOME -ZL WILL DO SO ONTO GROUND THAT
HAS EXPERIENCED RAIN ON WEDNESDAY. LOCAL TOP DOWN METHODOLOGY
PRODUCED A SHORT PERIOD OF -ZR/-ZL ACROSS THE COUNTIES ALREADY
WITHIN THE WSW - SO EXTENDED THE WSW UNTIL NOON THURSDAY FOR SOME
VERY LIGHT FREEZING DRIZZLE WHICH MAY ACCRETE UP TO 0.01 OR 0.02
INCHES...MOSTLY ACROSS ROBESON/BLADEN COUNTIES.
AS THE LOW PULLS AWAY THURSDAY NIGHT DRY ADVECTION COMMENCES AND SKY
CONDITIONS WILL IMPROVE DRAMATICALLY FRIDAY...ALTHOUGH LOW CLOUD
COVER WILL REMAIN AS A WEDGE OF HIGH PRESSURE BUILDS DOWN THE COAST.
STILL...FRIDAY WILL BE DRY...A NICE BREAK FROM THE ACTIVE WEATHER
RECENTLY.
TEMPS THROUGH THE PERIOD WILL REMAIN WELL BELOW NORMAL AS THE
CALENDAR APPROACHES MARCH. HIGHS BOTH THURSDAY AND FRIDAY WILL BE
ONLY IN THE LOW 40S...A FULL 20 DEGREES BELOW NORMAL...ALTHOUGH
FRIDAY WILL BE THE SLIGHTLY WARMER OF THE TWO. LOWS AT NIGHT WILL
ALSO BE VERY COLD...DROPPING WELL INTO THE 20S BOTH NIGHTS...BUT IN
THE DRIER COLUMN FRIDAY NIGHT MINS WILL LIKELY BE 2-3 DEGREES COOLER
THAN THOSE EXPERIENCED ON THURSDAY NIGHT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 400 AM WEDNESDAY...COLD AND DRY FOR THE WEEKEND...WITH A
WARMUP EXPECTED NEXT WEEK BUT ACCOMPANIED BY UNSETTLED WEATHER.
WEDGE OF HIGH PRESSURE WILL EXTEND DOWN THE EAST COAST DURING THE
WEEKEND AS CONFLUENCE BETWEEN THE EASTERN CONUS TROUGH AND
DEVELOPING SE RIDGE DRIVES RISING SURFACE PRESSURE. SATURDAY AND
SUNDAY WILL BOTH LIKELY BE DRY DAYS...BUT NE FLOW WITHIN THE WEDGE
WILL LEAD TO LOW CLOUDINESS THROUGH THE WEEKEND...BUT LIKELY IN A
VARYING STATE. THIS SUGGESTS THE SUN WILL BE PRESENT AT TIMES.
HOWEVER...TEMPS WILL...SHOCKINGLY...REMAIN WELL BELOW CLIMO THROUGH
THE WEEKEND.
WEDGE BREAKS DOWN ON MONDAY AND SURFACE HIGH PRESSURE SLIPS OFFSHORE
LEADING TO A DRAMATIC WARMING TREND FOR EARLY NEXT WEEK.
HOWEVER...THIS WARMTH WILL BE SOMEWHAT UNREALIZED AS UNSETTLED
WEATHER WILL DEVELOP MONDAY AND PERSIST THROUGH THE REMAINDER OF THE
PERIOD. LARGE TROUGH DEVELOPING WEST OF THE AREA WILL DRIVE
VORTICITY IMPULSES JUST NORTH OF THE AREA...OVERTOP A STALLED COLD
FRONT WHICH WILL HOVER ACROSS THE CAROLINAS. OVERALL...THERE APPEARS
TO BE LIMITED FORCING LOCALLY FOR PRECIP...BUT INCREASING CLOUDS
WITH AT LEAST PERIODS OF SHOWERS SEEM LIKELY MONDAY/TUESDAY.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
AS OF 05Z...IFR CONDITIONS WILL CONTINUE THROUGH THE PRE-DAWN HRS
OF WED WITH THE LOW CEILINGS THE PRIMARY REASON. WILL SEE VSBYS
DROP TO 2 TO 5 MILES IN FOG AT TIMES BUT THE LOW STRATUS WILL BE
THE PRIMARY AVIATION ISSUE THROUGH SEVERAL HRS AFTER SUNRISE WED.
NEXT SOUTHERN STREAM S/W TROF TO AFFECT THE FORECAST AREA WITH
ANOTHER ROUND OF WINTRY PCPN. DIFFERENCE WITH THIS NEXT SYSTEM IS
THAT COLD AIR WILL BE A LIMITING FACTOR THUS LEAVING ONLY THE
INLAND TERMINALS...FLO AND LBT...THAT COULD FACE POSSIBLE
FROZEN/FREEZING PCPN LATER TONIGHT INTO DAYTIME THU. AT THIS
TIME...THE CONSENSUS IS THAT THE COASTAL TERMINALS WILL BE JUST
PLAIN RAIN. THUS...LOW CEILINGS AND REDUCED HORIZONTAL VSBY TO
RETURN LATE IN THE TAF ISSUANCE PERIOD FOR ALL TERMINALS.
EXTENDED OUTLOOK...MVFR/IFR CONDITIONS EXPECTED AS LOW PRESSURE
WILL MOVE ACROSS THE TERMINALS TONITE INTO EARLY THU...THEN
ACCELERATE NE OFF THE CAROLINA COASTS AND OFFSHORE DURING THE DAY
ON THURSDAY. FINALLY...A RETURN TO VFR CONDITIONS FRI THROUGH
SAT. MVFR/IFR POSSIBLE SUNDAY.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST THIS EVENING AS WINDS AND SEAS ARE BEHAVING NICELY.
DISCUSSION FROM 645 PM FOLLOWS...
LOW PRESSURE WELL EAST OF THE SOUTH CAROLINA COAST WILL CONTINUE
TO PUSH NORTHEAST AND AWAY FROM THE AREA OVERNIGHT. THIS WILL
ALLOW WEAK HIGH PRESSURE INLAND TO SPREAD DOWN TO THE COAST
OVERNIGHT...WITH VEERING WINDS AND WEAKENING WIND SPEEDS. THE
SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT FOR THE NC WATERS WHERE
THE FRYING PAN SHOALS BUOY IS STILL REPORTING 7.5 FOOT SEAS. WEST
OF FRYING PAN SHOALS CONDITIONS APPEAR TO BE IMPROVING A LITTLE
FASTER.
NOTE THAT SOME WIND SENSORS NEAR THE COAST APPEAR TO HAVE FROZEN
ANEMOMETER CUPS AND ARE NOT TO BE TRUSTED.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM WEDNESDAY...DEEPENING LOW PRESSURE WILL BE MOVING AWAY
FROM THE COAST DURING THURSDAY...BUT THE GRADIENT WILL REMAIN
PINCHED THE FIRST PART OF THE SHORT TERM. GUSTY NORTH WINDS WILL
REACH OVER 20 KTS FIRST THING THURSDAY...BUT WILL EASE QUICKLY
THROUGH THE AFTN TO BECOME 10-15 KTS THURSDAY NIGHT WHILE REMAINING
FROM THE NORTH. HIGH PRESSURE WILL BEGIN TO WEDGE DOWN THE COAST ON
FRIDAY...CAUSING RENEWED TIGHTENING OF THE GRADIENT...AND WINDS WILL
INCREASE SLOWLY...BECOMING 20-25 KTS ONCE AGAIN BUT FROM MORE OF A
NE DIRECTION FRIDAY NIGHT. SEAS THURSDAY MORNING WILL BE 5-8
FT...BUT WILL FALL QUICKLY THROUGH THE DAY AND THE ONGOING SCA
SHOULD BE ALLOWED TO EXPIRE LATE THURSDAY. SEAS WILL REMAIN BELOW 6
FT THURSDAY NIGHT AND FRIDAY...BUT WILL RISE ONCE AGAIN TO 4-6 FT
FRIDAY NIGHT WHEN A RENEWED SCA MAY BE NEEDED.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 400 AM WEDNESDAY...WEDGE OF HIGH PRESSURE WILL STRENGTHEN
SATURDAY...AND AN EXTENDED PERIOD OF GUSTY 20-25 KT NE WINDS WILL
OCCUR THROUGH SATURDAY. THIS DRIVES WAVE HEIGHTS TO 4-6 FT...AND AN
SCA WILL LIKELY BE NEEDED THROUGH SATURDAY. SATURDAY
NIGHT...GRADIENT SLOWLY BEGINS TO WEAKEN AS THE WEDGE BREAKS DOWN.
THIS CAUSES WINDS TO EASE TO 10-15 KTS BY SUNDAY MORNING WHILE
REMAINING FROM THE NE. WINDS WILL EASE FURTHER AND THEN VEER TO THE
SOUTH AS THE WEDGE DISSIPATES LATE SUNDAY. WAVE HEIGHTS FALL ON THE
DECREASING WINDS...FROM 4-6 FT LATE SATURDAY...TO 2-4 FT SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST
THURSDAY FOR SCZ017-023-024.
NC...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST
THURSDAY FOR NCZ087-096-105.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...DCH/TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...DCH
MARINE...DCH/TRA/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
133 AM EST WED FEB 25 2015
.SYNOPSIS...
LOW PRESSURE WILL PULL AWAY FROM THE CAROLINAS TONIGHT AS WEAK
HIGH PRESSURE BUILDS OVERHEAD. A STRONG STORM SYSTEM WILL BRING
RAIN AND POSSIBLY SNOW WELL INLAND LATE WEDNESDAY INTO THURSDAY
MORNING. A MINOR WARMING TREND WILL BEGIN OVER THE WEEKEND.
MOISTURE WILL RETURN EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 930 PM TUESDAY...PRECIP IS COMPLETELY OFFSHORE AND CLOUDY
SKIES ARE ANTICIPATED TO CONTINUE OVERNIGHT. LATEST HIGH-RES
MODELS SHOW WITH THE LACK OF ADVECTION ACROSS SOUTH CAROLINA
TEMPERATURES MAY NOT FALL MUCH (IF ANY) OVERNIGHT. IN FACT WITH
TEMPERATURES NOW ABOVE FREEZING AT BOTH MYRTLE BEACH AND KINGSTREE
I AM NOT CERTAIN THERE`S MUCH CONCERN FOR ICE ON ROADS ACROSS SOME
PARTS OF NE SOUTH CAROLINA. I HAVE RE-WRITTEN THE SPECIAL WEATHER
STATEMENT TO FOCUS CONCERN ON SE NORTH CAROLINA WHERE WE ARE
SEEING REPORTS OF MULTIPLE CLOSED BRIDGES AND ELEVATED ROADS IN
WILMINGTON.
DISCUSSION FROM 645 PM FOLLOWS...
ITS BEEN A HECTIC FEW HOURS HERE. A BAND OF MODERATE FREEZING RAIN
THAT EXTENDED AS FAR WEST AS THE SC MIDLANDS EARLIER THIS
AFTERNOON IS FINALLY PUSHING OFF THE COAST NEAR CAPE FEAR THIS
EVENING. THIS PRECIPITATION FELL PRIMARILY ACROSS SE NORTH
CAROLINA WHERE AIR TEMPERATURES WERE IN THE 28-31
RANGE...PRODUCING LARGE AMOUNTS OF FREEZING RAIN BETWEEN 2-6 PM.
THE FREEZING RAIN SENSOR AT THE ILM (WILMINGTON) ASOS REPORTED
0.40 INCHES OF ICE ACCRETION TODAY. NORMALLY OUTPUT FROM THIS
SENSOR AGREES QUITE WELL WITH HUMAN-OBSERVED ACCRETION ON ELEVATED
OBJECTS AT THE NWS OFFICE...BUT THE ASOS SENSOR APPEARS TO HAVE
RUN A LITTLE HIGH WITH ITS TOTALS TODAY AS WE ARE ESTIMATING
CLOSER TO 0.25 INCHES OF ICE ACCRETION HERE. REPORTS RECEIVED VIA
FACEBOOK AND TWITTER CONFIRM WIDESPREAD 0.25 INCH ICE
ACCUMULATIONS AROUND THE CAPE FEAR AREA TODAY...VERIFYING THE ICE
STORM WARNING THAT WAS ISSUED EARLIER.
RADAR ECHOES ARE PUSHING OFFSHORE AT 40 KNOTS...HOWEVER ASOS/AWOS
OBSERVATIONS AND A PHONE CALL FROM THE NCDOT IN LUMBERTON EARLIER
CONFIRMS THAT A COUPLE HOURS OF FREEZING DRIZZLE CONTINUES BEHIND
THE RADAR-OBSERVED BACK EDGE OF THE PRECIP SHIELD. FOR THIS REASON
I WILL MAINTAIN THE WATCHES AND ADVISORIES UNTIL 8 PM EAST OF
I-95.
FOR THE REMAINDER OF THE OVERNIGHT PERIOD...IT APPEARS LOW CLOUDS
WILL HOLD TOUGH FOR ALL BUT PERHAPS THE LUMBERTON-BENNETTSVILLE
AREA WHERE SOME LIMITED CLEARING MAY DEVELOP LATE TONIGHT AS
MOISTURE THINS FROM ALOFT. THIS WILL PREVENT ANY SIGNIFICANT
RADIATIONAL COOLING AND LOWS SHOULD RANGE FROM 26-30...COOLEST
NEAR LUMBERTON AND WARMEST NEAR GEORGETOWN. THE 12Z & 18Z GFS
BOTH APPEAR TO BE UP THE SAME ANTICS PULLED DURING LAST WEEK`S
ARCTIC COLD WHERE IT SEVERELY OVERESTIMATES RADIATIONAL COOLING
POTENTIAL OVER MEAGER SNOWPACK ACROSS MUCH OF NORTH CAROLINA. THE
18Z NAM AND 22Z RUC LOOK MUCH MORE REASONABLE FOR TEMPERATURES
OVERNIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...MAIN FORECAST EMPHASIS IS THE STORM SYSTEM
CURRENTLY TAKING SHAPE IN THE NEW MEXICO REGION. THIS SYSTEM WILL
RACE ACROSS THE SOUTHERN STATES OVER THE NEXT 24-48 HOURS IN WHAT
IS BASICALLY A WESTERLY FLOW ALOFT. LOW PRESSURE WILL DEVELOP IN
THE GULF OF MEXICO AND MOVE OFFSHORE...EAST OF CHARLESTON BY 0600
UTC THURSDAY. BY 1200 UTC THURSDAY THE LOW WILL BE WELL EAST OF
THE OUTER BANKS.
FORCING WITH THE SYSTEM WILL COME IN A COUPLED FASHION WITH LOWER
LEVEL ISENTROPIC LIFT ON THE 290K SURFACE AND MID LEVEL
FRONTOGENESIS. THE DOMINANT COMPONENT IS BY FAR THE ISENTROPIC LIFT
AND THIS OF COURSE LEADS TO PRECIPITATION TYPE ISSUES ACROSS MOST OF
THE AREA.
FOR THE MOST PART...THERMAL PROFILES SUPPORT RAIN INITIALLY. AS
DYNAMIC COOLING TAKES PLACE ALONG WITH HEAVIER QPF RATES SOUNDINGS
COOL IN THE NORTHERN MOST COUNTIES TO MARGINALLY SUPPORT SNOW. THE
MODELS IF ANYTHING HAVE TRENDED JUST A LITTLE WARMER HOWEVER AND
CONFIDENCE IS NOT OVERWHELMING. THAT BEING SAID IF THE DYNAMIC LIFT
IS A LITTLE STRONGER THAN PERFECT PROGS...A COOLING OF THE PROFILE
COULD OCCUR WHICH WOULD LEAD TO MORE SUPPORT FOR SNOW. FOR NOW...I
HAVE A RAIN AND SNOW MIX FOR MARLBORO...ROBESON AND BLADEN COUNTIES
AND TOTAL ACCUMULATIONS OF JUST OVER TWO INCHES. THIS WARRANTS A
WINTER STORM WATCH FOR THESE AREAS WHICH WILL BE RAISED THIS
AFTERNOON. IT COULD BE A SITUATION WHERE SNOW IS THE PREDOMINANT
TYPE WITH RAIN MIXING FROM TIME TO TIME...AT LEAST A COUPLE OF HOURS
EITHER SIDE OF 0600 UTC. OVERALL I CANT RULE OUT A COUPLE OF INCHES
OF VERY WET/HEAVY SNOW IN THESE AREAS. IF SNOW DOES INDEED
DEVELOP...IT WONT TAKE LONG TO ACCUMULATE AS THE RATES SHOULD BE
VERY HIGH...AGAIN AT LEAST FOR A COUPLE OF HOURS EITHER SIDE OF 0600
UTC.
AS THE SYSTEM MOVES OUT BEYOND 0600 UTC PROFILES BRIEFLY SUPPORT
SOME SNOW IN OTHER AREAS AND I HAVE AMOUNTS RANGING FROM 0.7 INCHES
FROM NORTHWEST TO JUST OVER ONE HALF OF IN INCH CLOSER TO THE COAST.
THIS CAN PROBABLY BE ADDRESSED WITH A WINTER WEATHER
ADVISORY...ALTHOUGH TECHNICALLY JUST UNDER CRITERIA BUT WITH A
WINTER STORM WATCH FLOATING AROUND...IT MAY BE PRUDENT TO ISSUE AN
ADVISORY FOR PUBLIC IMPACT...AFTER THE CURRENT ONE HAS EXPIRED.
THE REMAINDER OF THURSDAY WILL FEATURE OVERCAST SKIES WITH PATCHY
DRIZZLE. HIGH TEMPERATURES WILL STRUGGLE TO REACH 40. YET ANOTHER
COLD AND BLUSTERY OVERNIGHT PERIOD FOR THURSDAY INTO FRIDAY MORNING
WITH LOWS IN THE MIDDLE 20S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 PM TUESDAY...BROAD LOW AMPLITUDE MID LEVEL FLOW ACROSS MOST
OF THE CONUS ON FRIDAY WITH LARGE HIGH PRESSURE AT THE SURFACE
CENTERED OVER EASTERN U.S. THIS WILL BRING A NORTHERLY FLOW LOCALLY
THAT WILL KEEP TEMPERATURES BELOW CLIMO AND LIKELY QUITE A FEW
CLOUDS TRAPPED UNDER AN INVERSION. NOT MUCH CHANGES HEADING INTO
SATURDAY AND SO THE FORECAST IS QUITE SIMILAR. ON SUNDAY THE CENTER
OF THE SURFACE HIGH SLIDES EAST AND EXTENDS A WEDGE AXIS INTO THE
CAROLINAS WHILE OFFSHORE TROUGHINESS DEVELOPS. MODELS LOOKING WETTER
AS THIS OCCURS AS WARM ADVECTION RIDES ATOP THIS SURFACE-BASED
AIRMASS LEADS TO GOOD ISENTROPIC UPGLIDE. GUIDANCE ALSO SUGGESTING A
MILDER AFTERNOON BUT THIS MAY NEED TO BE REVISITED ESPECIALLY IF
RAIN DOES MATERIALIZE. THE WEDGE BREAKS DOWN RAPIDLY BY MONDAY
ALLOWING FOR MODERATION IN TEMPERATURES AND PERHAPS SOME
UNSEASONABLY MILD NIGHTS BUT THE MOISTURE WILL REMAIN AND SOME
LIGHT RAIN CHANCES ARE STILL WARRANTED IF NOTHING ELSE DUE TO THE
APPROACH OF A WEAK COLD FRONT. THIS BOUNDARY APPEARS TO STALL ACROSS
THE AREA ON TUESDAY KEEPING CLOUDS AND RAIN IN THE FORECAST.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 05Z...IFR CONDITIONS WILL CONTINUE THROUGH THE PRE-DAWN HRS
OF WED WITH THE LOW CEILINGS THE PRIMARY REASON. WILL SEE VSBYS
DROP TO 2 TO 5 MILES IN FOG AT TIMES BUT THE LOW STRATUS WILL BE
THE PRIMARY AVIATION ISSUE THROUGH SEVERAL HRS AFTER SUNRISE WED.
NEXT SOUTHERN STREAM S/W TROF TO AFFECT THE FORECAST AREA WITH
ANOTHER ROUND OF WINTRY PCPN. DIFFERENCE WITH THIS NEXT SYSTEM IS
THAT COLD AIR WILL BE A LIMITING FACTOR THUS LEAVING ONLY THE
INLAND TERMINALS...FLO AND LBT...THAT COULD FACE POSSIBLE
FROZEN/FREEZING PCPN LATER TONIGHT INTO DAYTIME THU. AT THIS
TIME...THE CONSENSUS IS THAT THE COASTAL TERMINALS WILL BE JUST
PLAIN RAIN. THUS...LOW CEILINGS AND REDUCED HORIZONTAL VSBY TO
RETURN LATE IN THE TAF ISSUANCE PERIOD FOR ALL TERMINALS.
EXTENDED OUTLOOK...MVFR/IFR CONDITIONS EXPECTED AS LOW PRESSURE
WILL MOVE ACROSS THE TERMINALS TONITE INTO EARLY THU...THEN
ACCELERATE NE OFF THE CAROLINA COASTS AND OFFSHORE DURING THE DAY
ON THURSDAY. FINALLY...A RETURN TO VFR CONDITIONS FRI THROUGH
SAT. MVFR/IFR POSSIBLE SUNDAY.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST THIS EVENING AS WINDS AND SEAS ARE BEHAVING NICELY.
DISCUSSION FROM 645 PM FOLLOWS...
LOW PRESSURE WELL EAST OF THE SOUTH CAROLINA COAST WILL CONTINUE
TO PUSH NORTHEAST AND AWAY FROM THE AREA OVERNIGHT. THIS WILL
ALLOW WEAK HIGH PRESSURE INLAND TO SPREAD DOWN TO THE COAST
OVERNIGHT...WITH VEERING WINDS AND WEAKENING WIND SPEEDS. THE
SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT FOR THE NC WATERS WHERE
THE FRYING PAN SHOALS BUOY IS STILL REPORTING 7.5 FOOT SEAS. WEST
OF FRYING PAN SHOALS CONDITIONS APPEAR TO BE IMPROVING A LITTLE
FASTER.
NOTE THAT SOME WIND SENSORS NEAR THE COAST APPEAR TO HAVE FROZEN
ANEMOMETER CUPS AND ARE NOT TO BE TRUSTED.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...COASTAL WATERS WILL SEE A BRIEF RESPITE FROM
RUGGED CONDITIONS EARLY WEDNESDAY AS WINDS WILL BE RELATIVELY LIGHT
FROM THE NORTHWEST...TEN KNOTS OR LESS AS LOW PRESSURE DEVELOPS AND
MOVES WELL OFFSHORE...WINDS WILL TURN TO THE NORTHEAST AND INCREASE
IN MAGNITUDE TO 20-25 KNOTS BY EARLY THURSDAY MORNING. WINDS TURN TO
A MORE NORTHERLY DIRECTION DURING THE DAY THURSDAY AND SEEM
CONSISTENT IN A 10-15 KNOT RANGE...MOSTLY LEANING TOWARD THE HIGHER
SIDE. SIGNIFICANT SEAS START OUT SLOW AS WELL 1-2 FEET THEN RAMP UP
WELL INTO SMALL CRAFT CRITERIA BY LATE THURSDAY EVENING. BY LATE
THURSDAY HEIGHTS DROP BACK A BIT PROBABLY BELOW SMALL CRAFT
CRITERIA.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 300 PM TUESDAY...A LARGE AREA OF HIGH PRESSURE COVERING THE
EASTERN U.S. TO BRING A NORTHERLY WIND LOCALLY THAT WILL BE MODERATE
BUT NO FLAGS EXPECTED AT THIS TIME. THE CENTER OF THIS HIGH WILL
SHIFT EAST A BIT ON SATURDAY BUT THE LOCAL EFFECTS WILL BE THOSE OF
MINIMAL CHANGE. THE INCREASED DURATION OF THE LARGELY
COAST-PARALLEL NE WINDS COULD ALLOW FOR AN UPTICK IN OFFSHORE SEAS
BUT FOR NOW IT STILL SEEMS NO ADVISORIES WILL COME TO PASS. 5 FT
SEAS WILL BE QUITE PREVALENT ACROSS MOST ZONES AWAY FROM SHORE BUT
THE NEARSHORE WAVE SHADOWING MAY PRECLUDE EVEN CAUTIONARY HEADLINES.
THE HIGH SHIFTS FURTHER EAST ON SUNDAY AND EXTENDS A RIDGE AXIS ITO
THE CAROLINAS WHILE TROUGHINESS DEVELOPS JUST EAST OF THE FORECAST
WATERS. THIS HAS CAST SOME UNCERTAINTY ON THE FORECAST AS WIND SPEED
AND EVEN DIRECTION COULD VARY CONSIDERABLY DEPENDING ON WHERE THE
TROUGH-BORN WIND SHIFT DECIDES TO SET UP. CURRENTLY IT SEEMS TO BE
JUST FAR ENOUGH OFFSHORE THAT LOCAL WINDS STAY NORTHEASTERLY AND
GROW A BIT LIGHTER.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...WINTER STORM WATCH FROM THIS EVENING THROUGH THURSDAY MORNING
FOR SCZ017.
NC...WINTER STORM WATCH FROM THIS EVENING THROUGH THURSDAY MORNING
FOR NCZ087-096.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...DCH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
324 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
SNOW THIS MORNING AND WIND CHILLS TONIGHT WILL BE THE PRIMARY
FORECAST CHALLENGE FOR THE SHORT TERM.
NORTHWESTERLY FLOW ALOFT CONTINUES WITH A WEAK REINFORCING
SHORTWAVE DIGGING THROUGH THE DAKOTAS. THE BAND OF SNOW HAS BEEN A
BIT FURTHER EAST THAN EXPECTED...AND VALLEY CITY HAS BEEN DOWN TO
2SM WITH LIGHT SNOW AND IT LOOKS LIKE GWINNER HAS FINALLY
SATURATED AND IS GETTING SOME SNOW AT THE SFC. THE BAND MATCHES UP
WITH THE 850-700MB FRONTOGENESIS FAIRLY WELL...AND THE NAM HAS
THAT AREA STARTING TO MOVE OFF TO THE SOUTH LATER THIS MORNING.
THAT SEEMS TO FIT PRETTY WELL WITH THE RAP AND HRRR WHICH HAVE THE
QPF PEAKING AROUND 10Z AND THEN TAPERING OFF 3 TO 4 HOURS LATER.
TIME HEIGHT PLOTS FOR OUR SOUTHWESTERN CWA HAVE A GOOD OMEGA
BULLSEYE IN THE GOOD DENDRITIC GROWTH ZONE UNTIL AROUND 12Z.
CONTINUED TREND OF CATEGORICAL POPS IN THE FAR WEST FOR EARLY THIS
MORNING...WITH SOME ADJUSTMENTS FOR CURRENT RADAR TRENDS. RAP PUTS
OUT NEARLY 3 INCHES IN FAR SOUTHERN SARGENT COUNTY...BUT THIS
SEEMS A BIT HIGH GIVEN HOW LONG IT HAS TAKEN OBS SITES TO
SATURATE. CONTINUED WITH 1 TO 2 INCHES IN THE FAR SOUTHWESTERN CWA.
THE PRECIP SHOULD TAPER OFF BY MID MORNING AND WE WILL SEE
DECREASING CLOUDS MOVE SOUTH AS ARCTIC HIGH PRESSURE BUILDS INTO
THE NORTHERN PLAINS. THE HIGH WILL CONTINUE INTO TONIGHT AS THE
MAIN UPPER TROUGH CONTINUES TO DIG SOUTHEASTWARD. WITH CLEARING
SKIES AND THE COLD AIR MASS...WE SHOULD AGAIN GET DOWN TO THE -10
TO -20 RANGE TONIGHT. WINDS WILL DECREASE AS THE CENTER OF THE
HIGH MOVES DOWN INTO WESTERN ND...BUT THINK WE SHOULD HAVE ENOUGH
GRADIENT TO BRING WIND CHILLS DOWN TO ADVISORY LEVELS TONIGHT.
GIVEN THAT THERE IS A CURRENT HEADLINE FOR OUR NORTHEASTERN
COUNTIES AND WIND CHILL ADVISORIES ARE BECOMING A DIME A
DOZEN...WILL HOLD OFF ON ISSUING ONE FOR NOW. THE COLD HIGH
PRESSURE WILL REMAIN THROUGH THURSDAY WITH HIGHS JUST ABOVE ZERO.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
THURSDAY NIGHT THROUGH FRIDAY NIGHT...NORTHWESTERLY FLOW ALOFT
CONTINUES WITH THE CENTER OF THE SFC HIGH FINALLY STARTING TO MOVE
SOUTH AND EAST. WIND CHILLS COULD AGAIN BE AN ISSUE THURSDAY NIGHT
INTO FRIDAY MORNING. THE SOUTHERLY WINDS WILL INCREASE MORE ON
FRIDAY AS HIGH PULLS FURTHER AWAY. TEMPS SHOULD GET UP TO AROUND
10 BY FRIDAY AFTERNOON UNDER THE LATE WINTER SUN BUT WILL STILL BE
WELL BELOW AVERAGE AND WILL FEEL PRETTY RAW WITH THE INCREASING
WINDS. WEAK WARM AIR ADVECTION AND WINDS KEEPING US MIXED WILL
ALLOW TEMPS FRIDAY NIGHT TO FALL ONLY SLIGHTLY BELOW ZERO INSTEAD
OF THE TEENS BELOW.
SATURDAY TO WEDNESDAY...MODELS IN GOOD AGREEMENT WITH THE EXTENDED
LEADING TO HIGH CONFIDENCE FOR MUCH OF THE WEEKEND AND FIRST PART OF
NEXT WEEK. DRY WEATHER WILL CONTINUE ACROSS THE NORTHERN PLAINS WITH
THE ONLY SLGHT CHC FOR -SN BEING TUESDAY INTO WEDNESDAY FOR THE
SOUTHERN AND EASTERN PORTIONS OF THE AREA. 500MB SPLIT FLOW
CONTINUES WITH WESTERN CONUS THROUGH AMPLIFYING INTO THE FIRST PART
OF NEXT WEEK THE 500MB SW TO NE ORIENTED TROUGH AXIS PUSHES ACROSS
THE FA ON TUESDAY...BRINGING THE -SN POTENTIAL. TEMPERATURES NEAR
SEASONAL NORMALS WITH HIGHS IN THE 20S SAT-TUE WITH POST FROPA COLD
FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1150 PM CST TUE FEB 24 2015
SNOW BAND WILL AFFECT KDVL...BUT ONLY BRIEFLY THROUGH 09Z.
OTHERWISE...VFR CONDITIONS FOR THE TAF SITES WITH MVFR CONDITIONS
REMAINING TO THE WEST AND SOUTH.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...WIND CHILL ADVISORY UNTIL 10 AM CST THIS MORNING FOR MNZ005-006-
008-009.
&&
$$
SHORT TERM...JR
LONG TERM...JR/JK
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1241 AM CST WED FEB 25 2015
.UPDATE...
ISSUED AT 1241 AM CST WED FEB 25 2015
STRONG EASTERLY OVERRUNNING FLOW...COUPLED WITH A MID LEVEL S/WV
MOVING SOUTHEAST ACROSS THE NORTHERN PLAINS AND SOME DIVERGENT
FLOW ALOFT IN THE WAKE OF A DEPARTING UPPER JET STREAK...CONTINUES
TO RESULT IN WIDESPREAD LIGHT SNOW ACROSS MUCH IF NOT ALL OF
WESTERN AND CENTRAL NORTH DAKOTA EARLY THIS MORNING. POPS WERE
INCREASED ACCORDINGLY BASED ON RADAR MOSAIC AND NEAR TERM HIGH-RES
MODEL OUTPUT. STILL EXPECTING AN INCH MAX AS FAR AS SNOWFALL
ACCUMULATIONS NOW THROUGH EARLY WED AFTERNOON. MOST AREAS WILL
RECEIVE LESS THAN AN INCH.
A FEW BREAKS IN THE MID/UPPER LEVEL CLOUD DECK HAS RESULTED IN
SOME LIGHT FREEZING RAIN/DRIZZLE SO EXTENDED THIS MENTION THROUGH
THE OVERNIGHT TILL AROUND 15Z BASED ON NAM/GFS RH PROFILES AND
TIME HEIGHT CROSS-SECTIONS. LATEST SPC MESOANALYSIS AND IR SAT
IMAGERY BOTH INDICATE THIS AS WELL.
OTHER FORECAST ELEMENTS ON TRACK WITH NO MAJOR EDITS WITH THIS
UPDATE.
UPDATE ISSUED AT 850 PM CST TUE FEB 24 2015
LATEST RADAR IS NOT VERY IMPRESSIVE COMPARED TO WHERE WE HAD OUR
GREATEST SNOW AMOUNTS. HEAVIEST PRECIPITATION THIS EVENING HAS
BEEN ASSOCIATED WITH THE SURFACE LOW AND INVERTED TROUGH OVER
EASTERN MONTANA. LATEST ITERATIONS OF THE RAP/HRRR KEEP THIS
PRECIPITATION CONFINED TO MAINLY SOUTHWEST AND FAR SOUTH CENTRAL
NORTH DAKOTA...PERHAPS SLIDING EAST OF THE MISSOURI RIVER OVER THE
FAR SOUTH CENTRAL...THROUGH AROUND 08-09 UTC. THEREAFTER QPF IS
VERY LIGHT IN NATURE ALONG THE BAROCLINIC ZONE OVER CENTRAL NORTH
DAKOTA. NOT MUCH CURRENTLY HAPPENING FROM THE NORTHWEST INTO THE
SOUTH CENTRAL PRESENTLY. LATEST RAP SOUNDINGS DO SUGGEST A DRY
LAYER ALOFT AND HAVE ADDED A MENTION OF PATCHY FREEZING DRIZZLE
THROUGH THE REMAINDER OF THIS EVENING. THIS SHOULD DISSIPATE AFTER
MIDNIGHT AS MOISTURE ALOFT INCREASES.
WE DID GET SOME SNOW DURING THE DAY WITH AROUND AN 1.5 INCHES
REPORTED AT WILLISTON. HOWEVER MOST OF WHAT FELL DURING THE DAY
MELTED DUE TO OUR WARM TEMPERATURES. LATEST NAM/RAP/HRRR INDICATE
PRECIPITATION TAPERING QUICKLY FROM NORTH TO SOUTH WEDNESDAY WITH
PRECIPITATION MOSTLY ENDED BY MIDDAY...EXCEPT PERHAPS ALONG THE
SOUTH DAKOTA BORDER. THEREFORE HAVE ADJUSTED SNOW AMOUNTS AND HAVE
NOT INCLUDED WHAT FELL DURING THE DAY. WITH THIS...WE ARE NOW
LOOKING AT SNOW TOTALS TONIGHT THROUGH EARLY AFTERNOON WEDNESDAY
OF MAINLY AN INCH OR LESS. WITH HIGHER AMOUNTS...UP TO 2 INCHES
OVER THE FAR SOUTH CENTRAL FROM SIOUX...SOUTHERN GRANT AND
SOUTHERN MORTON COUNTIES...EAST THROUGH SOUTHERN EMMONS AND INTO
DICKEY AND MCINTOSH COUNTIES. LESSER AMOUNTS ARE NOTED OVER THE
TURTLE MOUNTAINS INTO THE NORTHERN JAMES RIVER VALLEY...AND OVER
THE FAR SOUTHWEST.
UPDATE ISSUED AT 606 PM CST TUE FEB 24 2015
FRONTAL BOUNDARY REMAINS OVER NORTHEAST MONTANA INTO FAR SOUTHWEST
NORTH DAKOTA. CURRENT RADAR IMAGERY SHOWS SOME HIGHER
REFLECTIVITIES FROM WEST CENTRAL INTO SOUTHWEST NORTH DAKOTA. A
FEW LIGHTER REFLECTIVITIES WERE LOCATED OVER THE NORTH CENTRAL. IN
GENERAL THOUGH...A DECREASE OVER THE PAST FEW HOURS. HAVE ADJUSTED
POPS DOWN EARLY THIS EVENING FOR MANY AREAS. THINK SNOW WILL PICK
UP AGAIN LATER TONIGHT INTO THE OVERNIGHT HOURS AS THE SURFACE LOW
SLIDES ALONG THE FRONTAL ZONE AND PUSHES THE INVERTED SURFACE
TROUGH INTO SOUTHWEST NORTH DAKOTA. THIS WILL ENHANCE THE
BAROCLINIC ZONE OVER WESTERN AND CENTRAL NORTH DAKOTA. OTHERWISE
NO BIG CHANGES EARLY THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 300 PM CST TUE FEB 24 2015
CURRENT SURFACE ANALYSIS PLACES PRIMARY LOW TO THE SOUTH OF JAMES
BAY WHILE SECONDARY LOW CONTINUES TO DEEPEN AND SLIDE SOUTH FROM
SOUTHWEST SASKATCHEWAN INTO NORTHEAST MONTANA. COLD FRONT CONTINUES
TO WORK SOUTH STRETCHING FROM EAST-CENTRAL SOUTH DAKOTA INTO FAR
SOUTHWEST NORTH DAKOTA. BEHIND THE FRONT...TEMPERATURES CONTINUE
TO EITHER HOLD STEADY OR SLOWLY DROP. UPPER LEVEL ANALYSIS PLACES
LOW OVER NORTHERN ONTARIO WITH SECONDARY LOW SLIDING FROM EASTERN
ARIZONA INTO NEW MEXICO...WHILE RIDGE REMAINS OFF THE PACIFIC
COAST. ACTIVE NORTHWEST FLOW REMAINS OVER OUR AREA. INITIAL ROUND
OF SNOW CONTINUES OVER PORTIONS OF THE AREA AFFILIATED WITH RIGHT
ENTRANCE REGION OF PASSING JET STREAK AND MODEST ISENTROPIC LIFT.
FOR THE REST OF THIS AFTERNOON INTO TONIGHT...AFOREMENTIONED JET
STREAK WILL CONTINUE TO PROGRESS OFF TO THE SOUTHEAST AND
ISENTROPIC LIFT STARTS TO WEAKEN WHICH MAY BRING A BRIEF BREAK IN
THE SNOW...THOUGH EXPECT ANOTHER ROUND OF ENHANCED SNOWFALL TONIGHT
AS SHORT WAVE OVER CENTRAL SASKATCHEWAN MAKES ITS APPROACH INTO
THE REGION. LATEST SUITE OF MODELS HAS DONE A BIT OF A SHIFT TO
THE EAST WHEN COMPARED TO PREVIOUS RUNS...SO HAVE PUSHED THE FOCUS
FOR HIGHER POPS AND SNOW AMOUNTS FURTHER TOWARDS CENTRAL NORTH
DAKOTA. COLD AIRMASS WILL CONTINUE ITS SHIFT INTO THE AREA WITH
LOWS MAINLY IN THE SINGLE DIGITS...AND BELOW ZERO READINGS OVER
PARTS OF NORTH CENTRAL.
ON WEDNESDAY...SNOW WILL SLOWLY SHIFT OFF TO THE SOUTH THROUGH THE
DAY WITH THE PROGRESSION WITH THE AFOREMENTIONED UPPER WAVE. COLD
AIRMASS WILL CONTINUE TO POUR INTO THE AREA BRINGING HIGH
TEMPERATURES CLOSE TO THE PREVIOUS NIGHTS LOWS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 PM CST TUE FEB 24 2015
THE EXTENDED CONTINUES TO BE DOMINATED BY A BLOCKING RIDGE OVER
THE EASTERN PACIFIC AND THE RESULTING DOWNSTREAM COLD UPPER LOW
FROM CENTRAL AND EASTERN CANADA THOUGH THE SOUTHWEST US. THIS WILL
KEEP THE EXTENDED PERIOD COLD AND DRY.
WEDNESDAY NIGHT THROUGH FRIDAY: A 1044MB ARCTIC HIGH PRESSURE CENTER
OVER SOUTHERN SASKATCHEWAN WEDNESDAY EVENING WILL PUSH SOUTHEAST
TOWARDS THE NORTH DAKOTA BORDER. THE MODELS PLACE THE HIGH CENTER
OVER CENTRAL NORTH DAKOTA BY THURSDAY AFTERNOON/EVENING...AND INTO
EASTERN SOUTH DAKOTA BY DAYBREAK FRIDAY MORNING. LOWS WEDNESDAY
NIGHT AND THURSDAY NIGHT SHOULD RANGE FROM 5 BELOW TO 20 BELOW
ZERO...WITH HIGHS ON THURSDAY FROM ZERO TO 10 ABOVE. WIND CHILLS
WILL BE THE MAIN CONCERN DURING THIS PERIOD. WIND CHILLS 25 TO 40
BELOW WILL BE A HAZARD WEDNESDAY NIGHT INTO THURSDAY MORNING AND
AGAIN THURSDAY NIGHT INTO FRIDAY MORNING OVER MOST OF THE
REGION...WITH THE FAR SOUTHWEST ESCAPING THE COLDEST WIND CHILL
VALUES.
THE WEEKEND INTO MONDAY WILL BE COOL AND DRY AS THE PRECIPITATION
WILL BE LIMITED TO THE BAROCLINIC ZONES SURROUNDING THE NORTHERN
PLAINS LEAVING NORTH DAKOTA DRY. HIGHS SHOULD BE MAINLY IN THE TEENS
AND 20S...WITH LOWS FROM 5 BELOW TO 10 ABOVE ZERO OVER MUCH OF THE
AREA THIS WEEKEND. A SLIGHT MODERATION IS POSSIBLE MONDAY WITH HIGHS
IN THE 20S TO LOWER 30S...BUT THEN COOLER AGAIN FOR TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1241 AM CST WED FEB 25 2015
A LOW PRESSURE SYSTEM WILL MOVE SOUTHEAST ACROSS THE WESTERN DAKOTAS
TONIGHT INTO WEDNESDAY MORNING. MVFR TO IFR CONDITIONS EXPECTED AT
KDIK TONIGHT AND WEDNESDAY MORNING IN PERIODS OF LIGHT SNOW AND FOG.
MAINLY MVFR TO LOW VFR CONDITIONS AT KBIS AND KISN TONIGHT AND
WEDNESDAY MORNING IN LIGHT SNOW. KMOT AND KJMS ARE EXPECTED TO
REMAIN MAINLY VFR BUT WITH PERIODS OF MVFR/IFR CEILINGS/VISIBILITIES
IN LIGHT SNOW TONIGHT. EASTERLY FLOW WILL SHIFT NORTHEAST AND THEN
NORTH WEDNESDAY WITH WINDS INCREASING FROM AROUND 10 KNOTS TONIGHT
TO 10 TO 20 KNOTS WEDNESDAY. EXPECT SKIES TO BECOME VFR AT ALL TAF
SITES WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JJS
LONG TERM...JV
AVIATION...NH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1156 PM CST TUE FEB 24 2015
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 238 PM CST TUE FEB 24 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN ARCTIC
COLD FRONT STRETCHING FROM AROUND WAUTOMA TO MARINETTE AND MOVING
EAST EARLY THIS AFTERNOON. SNOW SHOWERS DEVELOPED AHEAD OF THE
FRONT EARLIER TODAY AND LOCALLY DROPPED VSBYS TO A QUARTER OF A
MILE. THESE SNOW SHOWERS ARE NOW ENTERING LAKE MICHIGAN. OTHER
WEAKER SNOW SHOWERS EXIST RIGHT BEHIND THE FRONT. EXCEPT FOR THE
SNOW BELT...THESE SNOW SHOWERS SHOULD EXIT BY THE START OF THE
EVENING. WINDS ARE BECOMING STRONG AND GUSTY BEHIND THE FRONT WITH
SOME OBS REACHING UP TO 35 KNOTS OVER CENTRAL AND NORTH-CENTRAL
WISCONSIN. THESE GUSTY WINDS WILL SPREAD INTO EASTERN WISCONSIN
LATER THIS AFTERNOON. SOME CONCERN FOR THE DOOR PENINSULA AS WIND
DIRECTION AND PRESSURE RISES ARE FAVORABLE FOR NEAR WIND ADVISORY
WIND GUSTS FOR A FEW HOURS. THINK WILL FALL JUST SHORT OF THOSE
TYPES OF GUSTS THOUGH. PLENTY OF STRATO-CU AND SNOW SHOWERS WITHIN THE
ARCTIC AIR OVER THE ARROWHEAD AND HEADING TOWARDS NORTHERN
WISCONSIN. WINDS/TEMPS/WIND CHILLS/AND SNOW POTENTIAL ARE THE MAIN
FORECAST CONCERNS.
TONIGHT...THE ARCTIC COLD FRONT WILL EXIT NORTHEAST WISCONSIN LATE
IN THE AFTERNOON OR EARLY THIS EVENING. SHOULD SEE PRETTY GOOD WIND
GUSTS UP TO 40 MPH OVER DOOR COUNTY AS STRONG PRESSURE RISES ARRIVE
BEHIND THE FRONT EARLY THIS EVENING. GUSTS BETWEEN 30 AND 35 MPH
ARE POSSIBLE ELSEWHERE. THE WINDS SHOULD THEN SUBSIDE PRETTY
QUICKLY BY MID-EVENING AS ARCTIC AIR PLUNGES ACROSS NORTH-CENTRAL
AND NORTHEAST WISCONSIN...THOUGH WINDS SHOULD NOT DECOUPLE.
SCATTERED SNOW SHOWERS WILL LIKELY FOLLOW THE ARRIVAL OF THE
ARCTIC AIR ACROSS THE NORTH THIS EVENING...THEN DIMINISH/RETREAT
TO THE SNOWBELT AREAS OVERNIGHT. THE COMBINATION OF TEMPS FALLING
TO AROUND 10 OR 12 BELOW OVER N-C WISCONSIN AND PERSISTENT
NORTHWEST WINDS WILL HAVE WIND CHILLS FALLING BETWEEN 20 TO 25
BELOW OVER N-C WISCONSIN AND GENERALLY 10 TO 15 BELOW ELSEWHERE.
IN COORDINATION WITH WFOS MARQUETTE AND DULUTH...WILL NOT ISSUE A
WIND CHILL ADVISORY AND WILL INSTEAD HIGHLIGHT THE THREAT IN A
SPS.
WEDNESDAY...ARCTIC HIGH PRESSURE WILL REMAIN IN CONTROL ACROSS THE
REGION AS A WEAK DISTURBANCE SLIDES SOUTHEAST ACROSS THE CENTRAL
GREAT PLAINS. WILL SEE MID AND HIGH CLOUDS SPREAD OVERHEAD FROM
THIS DISTURBANCE...BUT NO REAL THREAT OF PRECIP THIS FAR INTO THE
ARCTIC AIR. BITTERLY COLD WIND CHILLS WILL BE MODERATING BY 9 OR 10
IN THE MORNING TO BETWEEN 10 AND 20 BELOW OVER N-C WISCONSIN. HIGHS
WILL BE RANGING FROM 5 TO 10 ABOVE OVER N-C WI TO 10 TO 15 FARTHER
SOUTH AND EAST.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 238 PM CST TUE FEB 24 2015
PATTERN ALOFT IS BEGINNING TO CHANGE...BUT NOT BEFORE ONE MORE
BATCH OF ARCTIC AIR PUSHES INTO THE AREA. EVENTUALLY A WESTERN
TROUGH WILL EMERGE AS THE RIDGE PREVIOUSLY IN PLACE REFORMS MORE
OVER THE PACIFIC. THE EASTERN TROUGH WILL RETREAT NORTH...AND
SOMETHING RESEMBLING A SOUTHERN STREAM WILL START TO BRING
SOUTHWEST FLOW ALOFT INTO WISCONSIN. THIS WILL BRING A WARMER AND
MORE MOIST AIRMASS FROM THE SOUTHWEST. THE RESULT WILL BE A SLOW
MODERATION OF TEMPERATURES THROUGH THE REST OF THE WEEK...FOLLOWED
BY CHANCES FOR SNOW LATE THIS WEEKEND AND EARLY NEXT WEEK.
WEDNESDAY NIGHT THROUGH SATURDAY...
PRIMARY FORECAST CHALLENGE IN THIS STRETCH WILL BE EARLY ON AS A NEW
ARCTIC AIRMASS SURGES INTO THE AREA WITH WEDNESDAY AND THURSDAY
NIGHTS SEEING THE LOWEST TEMPERATURES. HOWEVER...THE DEEP EASTERN
TROUGH PATTERN WE HAVE SEEN LATELY WILL BE DEAMPLIFYING. THIS MAY
HELP BLUNT THE DROP IN TEMPERATURES. IT WILL STILL BE VERY COLD
AND A PORTION OF THE AREA...PRIMARILY IN NORTH CENTRAL
WISCONSIN...MAY REQUIRE WIND CHILL ADVISORIES. EACH NIGHT HAS
ISSUES THOUGH. A SHORTWAVE WILL BE PASSING RELATIVELY NEAR THE
AREA WEDNESDAY NIGHT...AND THOUGH IT HAS APPEARED FOR SOME TIME
THAT IT WILL PASS WELL TO OUR SOUTH...GUIDANCE HAS DRIFTED NORTH
TODAY. IT IS POSSIBLE THAT FURTHER DRIFT MAY RESULT IN MORE
CLOUDINESS WHICH WOULD HELP ARREST THE FALL OF TEMPERATURES. ON
THURSDAY NIGHT...COLD TEMPERATURES WILL BE DRIVEN LARGELY BY THE
POTENTIAL FOR STRONG RADIATIONAL COOLING. BUT JUST HOW LOW WE GO
WILL DEPEND ON CLOUD COVER AND WHETHER OR NOT WINDS WILL BE CALM
OVERNIGHT...BOTH DIFFICULT THINGS TO FORECAST AT THIS RANGE. AFTER
THESE NIGHTS...THE AFOREMENTIONED PATTERN CHANGE SHOULD ENCOURAGE
A MODERATION OF TEMPERATURES FOR THE REST OF THE WEEK...THOUGH WE
ARE ONLY LOOKING TO AN INCREASE TO A LITTLE BELOW NORMAL FROM WELL
BELOW NORMAL.
ADDITIONALLY...THERE IS A SLIGHTLY INCREASED AREA OF OPEN WATER ON
LAKES SUPERIOR AND MICHIGAN AFTER RECENT GUSTY WINDS. THOUGH THE
WATER IS SURELY COLD...THE AIR MASS WILL BE COLDER AND WITH SOME
ONSHORE WIND TRAJECTORIES WEDNESDAY NIGHT...LAKE EFFECT FLURRIES
ARE NOT IMPOSSIBLE FOR THE VILAS COUNTY SNOW BELT AND PORTIONS OF
THE LAKE MICHIGAN SHORELINE IN EAST CENTRAL WISCONSIN...PARTICULARLY
THE BIT OF MANITOWOC COUNTY THAT JUTS OUT INTO THE LAKE AT
DIFFERENT ANGLE THAN THE REST OF THE SHORELINE.
SATURDAY NIGHT THROUGH TUESDAY...
WITH MORE SOUTHWEST FLOW ALOFT...A MID-LEVEL SHORTWAVE AND A WEAK
SURFACE LOW REFLECTION WILL BRING A CHANCE FOR SNOW TO THE AREA IN
THE SECOND HALF OF THE WEEKEND. AFTER A LARGE JUMP NORTH IN THE
MODEL GUIDANCE YESTERDAY THE ENVELOPE HAS SETTLED BACK TO THE
SOUTH A LITTLE BIT TODAY. THOUGH AT FIRST GLANCE IT APPEARS LIKE
THE AREA MAY STILL SEE A FAIR SHOT FOR SOME SYNOPTIC LIFT...A
DEEPER INVESTIGATION REVEALED LESS POTENTIAL THAN IT FIRST SEEMED.
STILL...THE WARMER AND MOISTER ADVECTION FROM THE SOUTHWEST MAKES
THE IDEA OF AT LEAST A LITTLE SNOW REASONABLE...PARTICULARLY IN
CENTRAL AND EAST CENTRAL WISCONSIN. IN THIS SCENARIO...IT WOULD BE
APPROPRIATE TO EXPECT SNOW TOTALS OF AROUND TWO INCHES OR LESS. A
COLD FRONT ASSOCIATED WITH A LOW AND ITS ATTENDANT SHORTWAVE IN
THE NORTHERN STREAM WILL SHIFT WINDS TO NORTHWESTERLY AND CUT OFF
THE SNOW. FORTUNATELY THE MORE ZONAL FLOW LOOKS TO PREVENT A
STRONG SURGE OF COLD AIR TO CHOP DOWN TEMPERATURES BEHIND THE
FRONT AT THIS TIME.
HOWEVER...AFTER ALL THIS TALK...IT IS IMPORTANT TO REMEMBER THAT
IT IS ONLY TUESDAY. THOUGH A BROAD SCENARIO IS PRESENT IN ALL THE
GUIDANCE AND CONFIDENCE IN THAT IS MODERATE TO HIGH...CONFIDENCE
IN THE DETAILS THIS FAR OUT IS RELATIVELY LOW...AND COULD HAVE
SIGNIFICANT INFLUENCES ON THE SENSIBLE WEATHER WITH THIS FEATURE.
IT WOULD NOT BE WISE TO RULE OUT A SOUTHERN MISS NOR HIGHER
SNOWFALL POTENTIAL FROM A NORTHWARD DEVIATION JUST YET.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1151 PM CST TUE FEB 24 2015
THE NEXT WEATHER SYSTEM WILL TRACK SW OF THE FORECAST AREA DURING
THIS TAF PERIOD...WITH MAINLY MID/HIGH CLOUDS EXPECTED OVER THE
REGION. SCT LIGHT LAKE EFFECT SNOW SHOWERS OR FLURRIES MAY
CONTINUE ACROSS VILAS COUNTY...AND NNE WINDS MAY BRING A FEW
FLURRIES TO THE MTW AREA WED EVENING. MOST PLACES WILL HAVE
PREVAILING VFR CONDITIONS...AND WINDS WILL BE GENERALLY LIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......LUCHS
AVIATION.......RE/TSK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
424 AM MST WED FEB 25 2015
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 424 AM MST WED FEB 25 2015
A STREAK OF DIFFICULT FORECASTS REMAINS IN TACT. A LOT GOING ON
THIS AFTERNOON AND EVENING...AND AGAIN POTENTIAL OF CONVECTION
THROWS A LOT OF VARIABILITY INTO MODEL OUTPUT AND FORECAST
CONFIDENCE FOR SNOWFALL AMOUNTS IN ANY PARTICULAR AREA.
HERE IS WHERE WE ARE...LIGHT SNOW IS OCCURRING IN THE MOUNTAINS
EARLY THIS MORNING BUT THIS SHOULD DECREASE AS SOME DRIER AIR
ALOFT WORKS ACROSS THE AREA THIS MORNING. ON THE PLAINS...WE
SHOULD SEE A FEW RAIN/SNOW SHOWERS SPREADING SOUTHEAST EARLY THIS
MORNING...MAINLY EAST OF A GREELEY TO LIMON LINE. CANT EVEN RULE
OUT A BIT OF FREEZING VERY LIGHT RAIN/SPRINKLES AS A FEW VALLEY
LOCATIONS MAY HOVER JUST BELOW FREEZING AS LIGHT PRECIP BEGINS.
CLOSER TO THE FRONT RANGE...OCCASIONAL GUSTY CHINOOK WINDS BUT
WARM TEMPERATURES WILL REMAIN IN PLACE...AND ENOUGH DOWNSLOPE TO
HAVE SOME BREAKS IN THE CLOUDS.
MAIN FORECAST ATTENTION TURNS TOWARD STRONG COLD FRONT ACROSS THE
PLAINS...WHICH IS ON TIME TO PUSH THROUGH BETWEEN 1 AND 3 PM.
TEMPERATURES WILL DROP BEHIND THE FRONT WITH ANTICYCLONIC UPSLOPE
DEEPENING. UPSTREAM MOISTURE SEEMS PLENTIFUL BASED ON REAL OBS AND
PRECIPITATION OCCURRING TO OUR NORTH. LAPSE RATES BECOME MORE
UNSTABLE...ESPECIALLY IN THE NAM WHERE SOME CAPE IS
INDICATED...WHILE GFS IS SLIGHTLY MORE STABLE. THE NAM...AS WELL
AS SEVERAL MESOSCALE MODELS INCLUDING THE NMM...ARW...AND THE
FINAL HOURS OF THE RAP AND HRRR INDICATE CONVECTION BLOSSOMING
WITH 2 INCH PER HOUR SNOW RATES. BUT THEY ALSO CONFINE THEM TO
AREAS VERY CLOSE TO THE FOOTHILLS...WHICH SEEMS POSSIBLE
CONSIDERING THE STRENGTH OF NORTH/NORTHEAST FLOW. IF THIS VERIFIES
THEN HEAVIER SNOW WOULD CERTAINLY BE MORE FOCUSED TOWARD THE
FOOTHILLS...AND MUCH LESS POTENTIAL FOR MUCH ACCUMULATION TOWARD
FORT COLLINS...GREELEY...AND POINTS JUST EAST OF DENVER. WE HAVE
TRENDED FORECASTS IN THIS DIRECTION SINCE THE STRONGER NORTHERLY
FLOW USUALLY SHUTS THOSE AREAS DOWN PRETTY QUICKLY...AND DRIER LOW
LEVEL AIR WITH COLDER ARCTIC AIR THIS EVENING WOULD HAVE A
TENDENCY TO DO THE SAME.
AT THE SAME TIME...THAT ALSO FOCUSES THE HEAVIER PRECIPITATION
TOWARD THE FOOTHILLS SO HAVE OPTED TO ISSUE WINTER STORM WARNINGS
FOR FOOTHILL LOCATIONS...MAINLY BOULDER COUNTY FOOTHILLS SOUTHWARD
TO JEFFERSON/DOUGLAS COUNTIES. THE SOUTHERN FOOTHILLS HAVE NOT
BEEN DOING VERY WELL WITH REGARD TO SNOW AMOUNTS IN THE PAST
COUPLE STORMS BUT GIVEN THE STRONGER FLOW LATER TODAY WE DO EXPECT
HEAVIER TOTALS THERE. ANOTHER CONCERNING AREA IF CONVECTION
BLOSSOMS AS MESOSCALE MODELS INDICATE WOULD BE THE WESTERN SUBURBS
FOR POTENTIAL WARNING CRITERIA. HARD TO EXACTLY SAY HOW THIS COMES
TOGETHER BUT FOR NOW WILL ISSUE ADVISORIES STARTING AROUND 3 PM
FOR THE DENVER/BOULDER METRO AREA AND PALMER DIVIDE. FORT COLLINS
PER DISCUSSION ABOVE SEEMS TO GET EXCLUDED FROM HEAVIER
PRECIPITATION AGAIN. SOME THREAT WESTERN SUBURBS COULD GET A QUICK
6 INCHES PLUS LATE THIS AFTERNOON/EVENING SO WILL MONITOR FOR
POTENTIAL UPGRADE TO WARNING. OVERALL...THERE WILL BE A VERY LARGE
DISPARITY WITH SNOW TOTALS WITH LITERALLY TRACE TO 10 INCH AMOUNTS
POSSIBLE IN PORTIONS OF THE DENVER METRO AREA...AND HARD TO
PINPOINT WHO GETS EXACTLY HOW MUCH. ONCE SNOW DEVELOPS WE DO
ANTICIPATE RAPID DETERIORATION OF CONDITIONS AS SNOW INTENSITY
COULD TURN DRY AND WARM ROADS INTO A QUICK SHEET OF PACKED
SNOW/ICE. THE LATE AFTERNOON/EVENING COMMUTE FOR THE
DENVER/BOULDER/PALMER DIVIDE/FOOTHILLS AREAS LOOKS DIFFICULT AT
THIS POINT.
FOR OVERNIGHT...SNOW INTENSITY IS EXPECTED TO GRADUALLY DECREASE
WITH UPSLOPE COMPONENT WEAKENING AND AIRMASS STABILIZING WITH
COLDER/DRIER BOUNDARY LAYER FLOW. MOST OF THE ACCUMULATING SNOW
SHOULD BE OVER BY DAYBREAK SO WILL RUN WARNINGS AND ADVISORIES TIL
6 AM.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 424 AM MST WED FEB 25 2015
THE MEDIUM RANGE MODELS CONTINUE TO INDICATE THAT THIS EVENINGS
SNOWFALL IS THE BEGINNING OF A PROLONGED PERIOD OF LIGHT SNOW
ACROSS MUCH OF THE FORECAST AREA...ESPECIALLY THE MOUNTAINS. THE
FLOW PATTERN ALOFT IS FORECAST TO BEGIN AS A CYCLONICALLY CURVED
NORTHWESTERLY FLOW WITH A COUPLE EMBEDDED SHORT WAVE TROUGHS. BY
FRIDAY EVENING...FLOW ALOFT ACROSS COLORADO WILL BECOME MORE
WESTERLY AS AN UPPER TROUGH BEGINS CARVING OUT OVER THE PACIFIC
NORTHWEST AND THEN GREAT BASIN. THE WESTERLY FLOW WILL BE MOIST
WITH ENOUGH CYCLONIC CURVATURE TO MAINTAIN WEAK QUASI-GEOSTROPHIC
FORCING FOR ASCENT ACROSS THE STATE. THIS WILL RESULT IN A
CONTINUATION OF LIGHT SNOWFALL THROUGH FRIDAY AND SATURDAY. AT
LOWER LEVELS...A VERY COLD AIRMASS WILL MOVE INTO THE REGION
BEHIND THIS AFTERNOONS COLD FRONT AND TAKE UP RESIDENCE OVER
NORTHEAST COLROADO THROUGH ABOUT SUNDAY. A LARGE SURFACE HIGH OVER
THE CENTRAL PLAINS WILL MAINTAIN SOUTHEASTERLY LOW LEVEL FLOW
ACROSS EASTERN COLORADO WELL INTO THE WEEKEND. THIS SHOULD
CONTINUE FEEDING MOISTURE INTO THE REGION WHICH COULD BE HELD
AGAINST THE FOOTHILLS BY A DENVER CYCLONE THAT WILL DEVELOP
THURSDAY NIGHT AND LAST THROUGH SATURDAY. WITH WEAK DYNAMICS
REMAINING OVERHEAD AND MOIST AIR AT LOWER LEVELS...LIGHT SNOW WILL
BE POSSIBLE WHILE THE UPPER FLOW PATTERN REMAINS IN PLACE.
BY LATE IN THE WEEKEND...THE UPPER TROUGH WILL SINK TO THE DESERT
SOUTHWEST...LEAVING COLORADO UNDER THE DEFORMATION ZONE DOWNSTREAM
OF THE UPPER CIRCULATION. THIS WILL PRODUCE THE HEAVIEST SNOWFALL
MORE OVER SOUTHWESTERN COLORADO...SIMILAR TO WHAT OCCURRED THIS
PAST MONDAY. BUT THE NORTH-CENTRAL COLORADO MOUNTAINS WILL BE ON
THE NORTHERN FRINGES OF THIS SYSTEM AND SHOULD RECEIVE AT LEAST
LIGHT SNOWFALL. NO FORECAST PERIOD IS EXPECTED TO CONTAIN
PARTICULARLY HEAVY SNOWFALL AMOUNTS...BUT SEVERAL CONSECUTIVE
PERIODS WITH 2 TO 4 INCHES OF NEW SNOW COULD ADD UP AFTER AWHILE.
TEMPERATURE-WISE...THE COLDEST TEMPERATURES FOR NORTHEAST COLORADO
WILL BE THURSDAY AND FRIDAY WITH ONLY SLIGHT MODERATION THROUGH
THE WEEKEND. DURING THE FIRST HALF OF NEXT WEEK...THE GFS AND
ECMWF HAVE SLIGHTLY DIFFERENT SCENARIOS INVOLVING THE WESTERN U.S.
TROUGH MOVING ACROSS COLORADO. THIS WILL KEEP THE RATHER UNSETTLED
WEATHER OVER THE STATE THROUGH THAT TIME. LITTLE WARMING CAN BE
EXPECTED UNTIL AFTER THE MAIN TROUGH CLEARS THE AREA. ALL IN
ALL...SNOWPACK CONDITIONS WILL ONLY IMPROVE THROUGH THE NEXT WEEK.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 424 AM MST WED FEB 25 2015
VFR CONDITIONS WILL PREVAIL THROUGH ABOUT 20Z. WINDS SHOULD TREND
FROM WEST/SOUTHWEST TO NORTHWEST/NORTHERLY THROUGH 18Z...AND THEN
BECOME GUSTY FROM THE NORTH/NORTHEAST WITH FRONTAL PASSAGE 20Z-
21Z WITH GUSTS AROUND 25 KNOTS EXPECTED. EXPECT IFR CONDITIONS AND
HEAVIER SNOW SHOWERS DEVELOPING 21Z-23Z WITH POTENTIAL FOR 1-2
INCH PER HOUR SNOW RATES AND TEMPO 1/4SM VISIBILITY 23Z-04Z.
HIGHEST THREAT WOULD BE AT KBJC AND KAPA...BUT SOME THREAT AT KDEN
TOO. OVERALL INTENSITY SHOULD DECREASE AFTER 04Z BUT IFR
CONDITIONS WILL LIKELY LINGER WITH LIGHT SNOW THROUGH EARLY
THURSDAY MORNING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM MST
THURSDAY FOR COZ039>041.
WINTER STORM WARNING FROM 2 PM THIS AFTERNOON TO 6 AM MST
THURSDAY FOR COZ035-036.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 6 AM MST
THURSDAY FOR COZ033-034.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM...DANKERS
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
752 AM CST WED FEB 25 2015
.SYNOPSIS...
ISSUED AT 330 AM CST WED FEB 25 2015
AT 330 AM...MID LEVEL CLOUDS WERE STREAMING INTO THE AREA AHEAD OF
A ROBUST CLIPPER SYSTEM. SNOW WAS CONTINUING TO DEVELOP ACROSS
PARTS OF SOUTH DAKOTA AND SOUTHWEST MINNESOTA. EARLY MORNING
TEMPERATURES WERE IN THE TEENS TO LOWER 20S AT MOST LOCATIONS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CST WED FEB 25 2015
THE MAIN FORECAST ISSUE IS THE IMPENDING POTENT CLIPPER SYSTEM AND
ASSOCIATED SNOWFALL AMOUNTS AND COVERAGE.
LOOKING AT THE VARIOUS SYNOPTIC AND HIGH RES MODELS...LATEST
TRENDS HAVE BEEN TOWARD HIGHER SNOWFALL AMOUNTS AND A SLIGHTLY
FARTHER NORTH AXIS OF THE HEAVIEST SNOW. THE INITIAL ISSUE IS
TIMING OF THE ONSET OF SNOW...DEPENDENT ON HOW THE DEFORMATION
ZONE/DRY SLOT SET UP. THE WRF IS A BIT FASTER IN BRINGING SNOW
INTO THE WEST THIS MORNING...WHILE THE RAP HAS A MORE PRONOUNCED
DRY SLOT EARLY IN THE EVENT. FOR PURPOSES OF THE FORECAST GRIDS
AND HEADLINES...HAVE GONE WITH THE EARLIER TIMING...WHICH CAN BE
ADJUSTED THROUGH THE DAY.
GIVEN THE STRENGTH AND DEPTH OF THE FORCING THROUGH THE DENDRITIC
LAYER...THE HIGHER SNOWFALL AMOUNTS LOOK REASONABLE BASED ON
AVERAGE SNOW RATIOS THROUGH THE BULK OF THE EVENT IN THE 14-19:1
RANGE. ALSO FAVORED CONSENSUS QPF...WHICH IS SLIGHTLY HIGHER TO
THE NORTH THAN WPC VALUES. THE END RESULT IS ROUGHLY 6-9 INCHES
FROM INDEPENDENCE...TO WAPELLO...FORT MADISON AND POINTS EAST.
HAVE UPGRADED THESE AREAS TO A WINTER STORM WARNING. FROM
DUBUQUE...THROUGH THE QUAD CITIES...WEST CENTRAL ILLINOIS...AND
FAR NORTHEAST MISSOURI...EXPECTING GENERAL 3-6 INCH AMOUNTS WITH A
WINTER WEATHER ADVISORY IN EFFECT. LOCALLY ENHANCED HIGHER SNOWFALL
AMOUNTS ARE NOT OUT OF THE QUESTION IN THE ADVISORY AREA.
ADJUSTMENTS TO SNOWFALL AMOUNTS/HEADLINES ARE INEVITABLE AS WE
HEAD THROUGH THE DAY AND INTO THIS EVENING.
PEAK SNOWFALL INTENSITY EXPECTED IN THE AFTERNOON/EVENING...WHICH
WILL MAKE FOR A HAZARDOUS COMMUTE WITH SNOW COVERED ROADS AND
REDUCED VISIBILITY. A NORTHWEST WIND AROUND 15 MPH WITH HIGHER
GUSTS WILL LIKELY PRODUCE SOME SHALLOW DRIFTING SNOW AT TIMES. THE
SNOW WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST LATE TONIGHT INTO
THURSDAY MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 330 AM CST WED FEB 25 2015
THURSDAY AND FRIDAY...VERY COLD PERIOD AS ARCTIC ~1042 MB HIGH
BUILDS INTO THE MIDWEST. FRESH POWDERY SNOW ON THE GROUND/LIGHT
WINDS (POSSIBLY DECOUPLED AT TIMES)/AND MAINLY CLEAR SKIES WILL SET
THE STAGE FOR VERY COLD OVERNIGHT LOWS. CURRENT FORECAST FAVORS THE
RAW GFS/ECMWF AS SUPERBLEND/NAM SEEM TO BE TOO WARM.
EXPECT WIDESPREAD LOWS BETWEEN -10 TO -15 F WHICH WOULD BE NEAR
RECORD TERRITORY FOR LATE FEBRUARY...SINGLE DIGIT SUB-ZERO LOWS ARE
MORE LIKELY SOUTH OF BURLINGTON. WINDS WILL REMAIN ON THE LIGHT SIDE
BUT EVEN AT 5-7 KTS THEY WILL BE ENOUGH TO CREATE DANGEROUS WIND
CHILLS BETWEEN -20 TO -30 F AT TIMES. VALUES NEAR -30 F SHOULD BE
RELATIVELY ISOLATED AND SHORT-LIVED. HIGHS ARE FORECAST TO BE IN THE
UPPER SINGLE DIGITS TO MID TEENS.
SATURDAY AND SUNDAY...SIGNIFICANT PATTERN CHANGE WILL OCCUR DURING
THIS TIME AS UPPER JET DIGS OUT A LARGE TROUGH OVER THE WESTERN U.S.
WHICH WILL CAUSE A BIG SHIFT IN THE ORIENTATION OF THE 850 MB
BAROCLINIC ZONE TO A SW-NE DIRECTION.
THERE HAS BEEN A CONSISTENT SIGNAL OF SIGNIFICANT LOW/MID LEVEL
MOISTURE ADVECTION FROM THE SW U.S. AND FROM THE GULF OF MEXICO FOR
SAT NIGHT INTO SUN. THEREFORE...A PERIOD OF SNOW IS LIKELY WITH
AMOUNTS UNCERTAIN THIS FAR OUT. WITH THE LACK OF A STRONG SHORTWAVE
TROUGH/VORTICITY MAX...MODELS DEVELOP LINEAR-LOOKING FRONTAL PRECIP
AND DO NOT DEVELOP A COHERENT SFC LOW WHICH WOULD PUT SOMEWHAT OF A
LIMIT ON THIS SYSTEM. DAYTIME TEMPS WILL BE IN THE 20S ON SAT AND
THE UPPER 20S TO LOWER 30S ON SUN.
MONDAY AND TUESDAY...CHANCE OF PRECIP MORE LIKELY LATER IN THE DAY
AND INTO TUE. MODELS STILL STRUGGLING WITH WHEN TO EJECT ORGANIZED
500 MB VORTICITY MAX OUT OF THE FOUR CORNERS AREA. THE GFS HAS A
WELL ORGANIZED SFC LOW TRACKING FROM OKLAHOMA TO NORTHERN INDIANA
WHICH IS FAVORABLE FOR WIDESPREAD PRECIP IN THE DVN CWA. WARMER AIR
ALOFT MAY MAKE IT FAR ENOUGH NORTH TO BRING VARYING PRECIP TYPES TO
PORTIONS OF THE FORECAST AREA. STAY TUNED. EARLY LOOK AT FORECAST
HIGHS ARE IN THE UPPER 20S TO MIDDLE 30S ON TUE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 703 AM CST WED FEB 25 2015
12Z TAFS UPDATED FOR MINOR ADJUSTMENTS TO TIMING ON SNOW
ONSET...BETWEEN 15 AND 17Z THIS MORNING. EXPECTING LIFR CEILINGS
AND/OR VISIBILITIES WITH PERIOD OF MODERATE TO HEAVY SNOW. SNOW
WILL TAPER OFF FROM NW TO SE OVERNIGHT BUT IFR CEILINGS WILL
PERSIST THROUGH 12Z.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST THURSDAY FOR
CLINTON-DELAWARE-DUBUQUE-JACKSON-JONES-SCOTT.
WINTER STORM WARNING FROM NOON TODAY TO 6 AM CST THURSDAY FOR
CEDAR-DES MOINES-HENRY IA-JEFFERSON-LEE-LOUISA-MUSCATINE-
VAN BUREN.
WINTER STORM WARNING UNTIL 3 AM CST THURSDAY FOR BENTON-BUCHANAN-
IOWA-JOHNSON-KEOKUK-LINN-WASHINGTON.
IL...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST THURSDAY FOR
HENRY IL-MERCER-ROCK ISLAND.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST
THURSDAY FOR HANCOCK-HENDERSON-MCDONOUGH-WARREN.
MO...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST
THURSDAY FOR CLARK-SCOTLAND.
&&
$$
SYNOPSIS...RP KINNEY
SHORT TERM...RP KINNEY
LONG TERM...UTTECH
AVIATION...RP KINNEY
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
546 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CST WED FEB 25 2015
FIRST OFF...WE WILL START WITH WHAT GOT CHANGED OVERNIGHT. SNOW
ACROSS NODAK HAS COME IN CONSIDERABLY FARTHER NE THAN WHAT PREVIOUS
MODELS EVEN YESTERDAY AFTERNOON WERE SHOWING. THE HRRR/RAP/HOPWRF
ALL PICKED UP ON THIS NORTHWARD SHIFT IN THE SNOW AND THE FORECAST
WAS UPDATED ACCORDINGLY. NOW HAVE AN INCH OF SNOW FORECAST AS FAR
NORTH AS A MORRIS...MSP...PEPIN LINE. HAVE ALSO BOOSTED SNOW TOTALS
TO THE SOUTH OF THERE...WITH THREE 3+ INCHES FORECAST AS FAR NORTH
AS THE MN RIVER TO ALBERT LEA. WITH THE HIGHER SNOW AMOUNTS...DID
EXPAND THE ADVY UP TO THE UPPER MN RIVER AND ALONG THE I-90
CORRIDOR. WE WILL HAVE TO KEEP A CLOSE EYE SOUTHWEST OF A ST. JAMES
TO ALBERT LEA LINE AS SNOW TOTALS THERE ARE CURRENTLY IN THE 4-6
INCH RANGE AND THERE IS THE POTENTIAL A FEW OF THOSE COUNTIES MAY
NEED TO BE UPGRADED TO A WARNING IF QPF COMES IN ANY HIGHER THAN
WHAT IT IS CURRENTLY PEGGED TO BE.
RAP H5 ANALYSIS THIS MORNING SHOWS TWO WAVES OF INTEREST OUT IN THE
DAKOTAS...ONE IS MOVING INTO CENTRAL SODAK...WHILE THE SECOND IS
MOVING INTO NW NODAK. THE SNOW CURRENTLY MOVING INTO SW MN IS THE
RESULT OF THE SRN WAVE...BUT THIS NRN WAVE WILL BE THE DOMINATE
PLAYER TODAY...WHICH LIKELY EXPLAINS THE NORTHWARD SHIFT WE HAVE
SEEN IN THE GUIDANCE OVERNIGHT. BESIDE THESE WAVES...THERE IS A
PRETTY STRONG NW-SE ORIENTED H85 THERMAL GRADIENT THAT LINES UP FROM
NW NODAK INTO NW IOWA AND WITHIN THIS BAROCLINIC ZONE YOU WILL FIND
OUR DEVELOPING SNOWSTORM. AS WE GO THROUGH THE DAY...THIS NW-SE
GRADIENT WILL TAKE ON MORE OF E-W GRADIENT...WITH THE PIVOT IN THE
GRADIENT HAPPENING ACROSS NORTHERN IOWA...WHICH IS WHY THE 3Z AND 6Z
HOPWRF GO ABSOLUTELY GANGBUSTERS WITH PUTTING OUT OVER A FOOT OF
SNOW IN NORTH CENTRAL IOWA.
FOR THIS FORECAST...THE HOPWRF/RAP/HRRR ARE NEARLY IDENTICAL WITH
HOW FAR NORTH THE 0.25" QPF LINE WILL SETUP...SO FELT CONFIDENT IN
EXPANDING THE WINTER WEATHER ADVISORY ACROSS THE I-90 CORRIDOR AND
UP THE MN RIVER TO YELLOW MEDICINE AND LAC QUI PARLE COUNTIES. GIVEN
HOW COLD THE ATMO IS...WE ARE LOOKING AT SNOW RATIOS LIKELY UP NEAR
20:1...SO A QUARTER INCH OF QPF SHOULD HAVE NO PROBLEM PUTTING DOWN
MORE THAN 3 INCHES OF SNOW. AS MENTIONED ABOVE...THE QPF/SNOWFALL
FORECASTS FROM THE HOPWRF/HRRR/RAP DOWN AROUND FAIRMONT ARE A BIT
WORRISOME AND THERE IS CERTAINLY A GOOD CHANCE WE MAY NEED A WARNING
OR TWO IN SOUTH CENTRAL MN.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 408 AM CST WED FEB 25 2015
A TRANQUIL PERIOD IS EXPECTED THROUGH THE MAJORITY OF THE LONG
TERM. THINGS GET A LITTLE MORE INTERESTING EARLY NEXT WEEK BUT
WE/LL SEE HOW LONG THAT LASTS GIVEN THIS WINTER.
ANOTHER MASSIVE AREA OF HIGH PRESSURE SLIDING DOWN THE EASTERN
SLOPES OF THE ROCKIES WILL BRING A FRESH SURGE OF ARCTIC AIR
THURSDAY AND FRIDAY. MIXING TO 925 MB THURSDAY ONLY YIELDS HIGHS
IN THE LOW SINGLE DIGITS. FULL SUN IS EXPECTED AND WHILE STILL
WEAK...THE HIGHER ANGLE MAY BR ABLE TO SQUEEZE OUT AN EXTRA DEGREE
OR TWO. THE CENTER OF THE RIDGE WILL SINK SOUTHEAST ACROSS THE
EASTERN DAKOTAS OVER THE MISSOURI RIVER THURSDAY NIGHT. WINDS WILL
LIKELY DECOUPLE IN SHELTERED AREAS AND VERY COLD LOWS APPEAR
PROBABLE...PARTICULARLY CLOSEST TO THE HIGH IN SOUTHWEST
MN...WHICH ALSO COINCIDES WITH THE DEEP SNOWPACK NOW EXPECTED FROM
THE SYSTEM TODAY. LOWERED TEMPS SEVERAL DEGREES IN THIS AREA AND
THE COLDEST LOCATIONS COULD APPROACH 20 BELOW. ALTHOUGH TOO
COLD...THE 00Z GEM IS THE BEST PROXY TO PLACE WHERE THE COLDEST
TEMPS SHOULD OCCUR.
MODERATING TEMPS WILL RETURN FOR THE WEEKEND AS A SOUTHERLY
SURFACE FLOW AND A WEAKENING OF THE CENTRAL AND EASTERN CONUS
TROUGH NEGATE THE OCCURRENCE OF ADDITIONAL ARCTIC AIR INTRUSION.
OF PARTICULAR INTEREST IS A LOADING OF ENERGY ACROSS THE
SOUTHWESTERN U.S. IN A DEEPENING POSITIVELY TILTED TROUGH
EXTENDING OFF THE SOCAL COAST. A ZONAL UPPER JET EXTENDING TO THE
EAST WILL WICK AWAY PIECES OF THIS ENERGY AND EJECT THEM ACROSS
THE CENTRAL PLAINS EAST TO THE OHIO VALLEY. ANY INFLUENCES WITH
THESE WAVES SHOULD REMAIN SOUTH OF THE FORECAST AREA. LOWERED POPS
THIS WEEKEND BUT DID NOT COMPLETELY REMOVE THEM YET ACROSS SRN MN
AND WRN WI.
BY LATE IN THE WEEKEND...THERE ARE STRONG INDICATIONS THE JET
STREAM WILL FINALLY BUCKLE NORTH AS MID LEVEL RIDGING BUILDS
ACROSS THE SOUTHEAST. THIS WILL BEGIN TO SET THE STAGE FOR A
SIGNIFICANT PATTERN SHIFT NEXT WEEK BUT THE DETAILS ARE FAR FROM
CERTAIN WITH A COMPLEX EVOLUTION OF THE SOUTHWESTERN TROUGH THAT
COULD LEAD TO BIG DIFFERENCES DOWNSTREAM. AT THE MOMENT...THE
DETERMINISTIC RUNS OF THE GFS...ECMWF...AND CANADIAN ALL AGREE IN
A FAIRLY ROBUST WINTER STORM IMPACTING PORTIONS OF THE PLAINS AND
UPPER MIDWEST EARLY NEXT WEEK. HOWEVER...ENSEMBLE MEMBERS ARE ALL
OVER THE PLACE. WE HAVE SEEN SYSTEMS TREND AWAY FROM THE LOCAL
AREA TIME AND TIME AGAIN THIS WINTER...BUT THE SOUTHEAST RIDGE
BOLSTERS OUR PROBABILITIES A BIT MORE AND THUS THIS PERIOD WILL
NEED TO BE WATCHED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 546 AM CST WED FEB 25 2015
SNOW RAPIDLY EXPANDING ACROSS SW MN THIS MORNING HAS BEEN HANDLED
WELL BY THE HRRR AND HOPWRF...AND STUCK CLOSE TO THOSE MODELS
FOR TIMING SNOW ACROSS SRN MN THIS MORNING. ONLY SURPRISE SO FAR
HAS BEEN THE SNOW BEING REPORTED AT AXN...DID NOT EXPECT THE SNOW
TO MAKE IT THAT FAR NE...BUT THAT DOES BODE WELL FOR MSP SEEING AT
LEAST A FEW TENTHS OF AN INCH OF SNOW THIS MORNING. STC/RNH/EAU
STILL LOOK TO MISS THIS ONE. FOR RWF...NOTHING HAS CHANGED...THEY
WILL STILL FEEL THE BRUNT OF THIS SYSTEM...WITH CLOSE TO 3 INCHES
EXPECTED. NON VFR CONDITIONS LOOKS TO BE BASICALLY TIED TO THE
SNOWFALL...SO EXPECT VFR CONDITIONS TO MOVE IN QUICKLY BEHIND THE
SNOW THIS AFTERNOON...WITH SUBSIDENCE AND COLD/DRY AIR FROM THE
NEXT INCOMING HIGH LEADING TO SKIES CLEARING OUT OVERNIGHT AND
MAINLY CLEAR CONDS FOR THU/FRI.
KMSP...MSP WILL BE ON THE EDGE OF THE SNOW SHIELD. LAST COUPLE
RUNS OF THE HRRR HAVE SHOWN THE 1 INCH SNOW LINE GETTING TO ABOUT
5 MILES SOUTH OF THE AIRPORT...WHILE NOTHING FALLS 5 MILES NORTH
OF THE FIELD...SO NEEDLESS TO SAY...MSP COULD GO EITHER WAY WITH
GETTING OR NOT GETTING SNOW THIS MORNING. HOWEVER...THE FACT THAT
-SN IS CURRENTLY BEING OBSERVED AS FAR NE AS AXN AND SAUK CENTER
/AS WELL AS HERE AT THE OFFICE IN CHANHASSEN/...STILL FEEL MSP
WILL SEE SOME LIGHT SNOW...ESPECIALLY BETWEEN 15Z AND 18Z. AS FOR
THE REST OF THE TAF...CONFIDENCE IS HIGH IN VFR CONDS WITH NORTH
WINDS AROUND 10KTS.
/OUTLOOK FOR KMSP/
THU...VFR. WINDS NW 5-10 KTS.
FRI...VFR. WINDS WSW 5 KTS.
SAT...VFR. WINDS S 10G15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR MNZ054-
064-073-074.
WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR MNZ082-
083-091>093.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...BORGHOFF
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS HASTINGS NE
534 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST WED FEB 25 2015
...ARCTIC AIR RETURNS WITH A VENGEANCE WITH FRONTAL PASSAGE
ACCOMPANIED BY POSSIBLE RAIN/SNOW SHWRS FOLLOWED BY HOWLING N
WINDS UP TO 50 MPH...
ALOFT: SEVERAL WEAK/SUBTLE SHORTWAVE TROFS WILL CROSS THE FCST
AREA THRU TONIGHT IN NW FLOW. THE LEAD TROF WILL BE THE POTENTIAL
WX- MAKER WHICH WILL MOVE THRU 15Z-00Z...ASSOCIATED WITH THE
PASSAGE OF THE SFC LOW.
SURFACE: AN ARCTIC COLD FRONT EXTENDED FROM HUDSON BAY THRU THE
GREAT LAKES ACROSS IA TO LOW PRES OVER SD AND THEN NW INTO CANADA.
THIS LOW WILL HEAD SE ACROSS NEB TODAY AND IN ITS WAKE THE FRONT
WILL SURGE S TODAY AND WILL BE S OF THE FCST AREA BY SUNSET.
ARCTIC HIGH PRES THEN BEGINS BUILDING IN TONIGHT FROM CANADA.
EARLY THIS MORNING: CLOUDS WILL CONT TO INCREASE FROM THE NW.
GENERALLY MILD WITH TEMPS AT OR ABOVE FRZG MOST LOCATIONS.
HAZARDS: N WINDS WILL GUST 45-50 MPH 12PM-12AM. DANGEROUS WIND
CHILLS DOWN TO -20F LATE TONIGHT...N OF I-80.
TODAY: NOT SURE HOW IT UNFOLDS. WE KNOW FOR SURE THAT THE
STEADIEST PRECIP WILL BE E OF THE FCST AREA...ON THE COLD SIDE OF
THE FRONT IN THE WAA. SPOTTY ECHOES HAVE BEEN INCREASE THRU THE
NIGHT SW OF THE LOW THRU THE BLACK HILLS INTO THE PANHANDLE.
UPSTREAM SOUNDINGS SHOW A LOT OF DRY AIR IN THE LOW-LVLS. SO FAR
HAVE ONLY SEEN ONE STATION REPORT SPRINKLES UPSTREAM.
OVERALL EXPECT A M/CLOUDY DAY OVER S-CNTRL NEB AND BECOMING
M/CLOUDY OVER N-CNTRL KS. MOST MESOSCALE MODELS SUGGEST A
NARROW/BROKEN BAND OF STRONGLY-FORCED SHWRS WILL DEVELOP ALONG THE
FRONT WHICH COULD BRIEFLY CHANGEOVER TO SNOW BEFORE ENDING...
PRIMARILY N OF HWY 6. PRECIP WILL INITIALLY STRUGGLE TO REACH THE
GROUND. THE ENVIRONMENT IS NOT FAVORABLE FOR MUCH MEASURABLE
PRECIP.
THE LOWEST CONFIDENCE PORTION OF THE FCST IS TEMPS. WE COULD BE
TOO COOL. MULTIPLE OVERNIGHT CYCLES OF THE RAP SUGGEST 50F UP TO
I-80 AND NEARING 60 OVER N-CNTRL KS. I COULD ONLY ENVISION THAT
HAPPENING WITH FULL SUN AND THAT IS NOT EXPECTED. USED CONSENSUS
OF HI-RES SHORT-TERM MODELS FOR HIGHS AND THEN NUDGED HIGHS MORE
INTO THE 50S OVER N-CNTRL KS IN COORDINATION WITH KS OFFICES.
TEMPS WILL FALL THIS AFTERNOON N OF I-80 BEHIND THE FRONT.
WINDS: BLENDED THE 18Z/00Z MAV MOS 50-50. N WINDS WILL HOWL...
GUSTING 45-50 MPH IN THE TIGHT PRES GRADIENT/CAA BEHIND THE LOW. 6
HR PRES RISES OF 12 MB ARE LIKELY.
TONIGHT: CLOUDY...WINDY AND TURNING VERY COLD. WINDS WILL BE
STRONGEST PRIOR TO MIDNIGHT. TEMPS PLUMMET INTO THE SINGLE DIGITS
OVER N-CNTRL NEB AND LINGERING WINDS WILL PUSH WIND CHILLS AS LOW
AS -20F.
CAA WILL RESULT IN SOME MODEST INSTABILITY IN THE LINGERING
STRATUS WHICH WILL COOL INTO THE IDEAL SNOW GROWTH LAYER. SO KEPT
THE MENTION OF FLURRIES FROM THE PREVIOUS FCST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 504 AM CST WED FEB 25 2015
THE MAIN FORECAST CONCERN IS THE CHANCE FOR SNOW OVER THE WEEKEND
AND INTO EARLY NEXT WORK WEEK.
WE START OUT THE LONG TERM FORECAST THURSDAY WITH AN EXPANDING
SURFACE RIDGE BUILDING IN. MODEL SOUNDINGS INDICATE THAT WE COULD
HANG ON TO SOME STRATUS A LITTLE LONGER THAN WHAT OUR INITIALIZED
SUPERBLEND ADVERTISES AND I HAVE BUMPED UP SKY COVER. MODELS ARE
IN GOOD AGREEMENT WITH 850 MB TEMPERATURES IN THE -165 TO -20
RANGE FOR THURSDAY...WE WILL STRUGGLE TO GET HIGHS IN THE TEENS
FOR MOST AREAS. WE MAY MAKE IT TO AROUND 20 IN OUR SOUTH. I USED
THE NAM FOR HIGH TEMPERATURES...BUT THIS IS DEPENDING ON WIND
SPEEDS STAYING UP A BIT. GFS ACTUALLY INDICATES SOME AREA IN OUR
NORTHEAST NOT BREAKING INTO THE TEENS FOR HIGHS...AND THIS MAY
VERY WELL HAPPEN...ESPECIALLY IF WIND SPEED DROPS AND WE GET A
LITTLE MORE SKY COVER HANGING AROUND.
THE 1040 MB HIGH WILL BE CENTERED OVER THE NORTHERN PLAINS BY
THURSDAY EVENING AND WILL CONTINUE MOVING SOUTH SOUTHEAST.
THURSDAY WILL FEEL QUITE COLD. WIND CHILLS MAY BRIEFLY BREAK INTO
THE SINGLE DIGITS FOR THE AFTERNOON BEFORE MAKING ANOTHER DIVE.
WIND SPEED COULD BE JUST STRONG ENOUGH THURSDAY NIGHT TO KEEP WIND
CHILLS IN THE -15 TO -20 RANGE IN OUR NORTHEAST. WIND SPEEDS
SHOULD DIMINISH LATE AS THE CENTER OF THE SURFACE HIGH SLIDES
NEARER...MAYBE AS CLOSE AS EASTERN NEBRASKA. THIS WILL CAUSE WIND
TO DROP OFF QUITE A BIT AND WITH ANTICIPATED MOSTLY CLEAR SKY FOR
MUCH OF THE CWA...WE COULD WIND UP BEING BELOW ZERO FOR A
CONSIDERABLE PORTION OF THE CWA. ORD COULD REALLY TANK TO NEAR
-10. NUMERICAL MODELS ARE ALL TRENDING COLDER FOR THURSDAY
NIGHT/FRIDAY MORNING AND I HAVE CONTINUED THIS TREND. I BUMPED
DOWN TEMPERATURES CONSIDERABLY COMPARED TO SUPERBLEND
INITIALIZATION. WE MAY HOLD NEAR ZERO IN OUR SOUTH/SOUTHWEST WHERE
WE MAY HAVE A FEW MORE CLOUDS AROUND ALONG WITH SLIGHTLY STRONGER
WIND SPEED.
NUMERICAL MODELS ALL TEND TO KEEP US DRY FRIDAY/FRIDAY NIGHT FOR
THE MOST PART...WITH THE EXCEPTION OF PERHAPS SOME FLURRIES IN
ADVANCE OF THE NEXT WINTER SYSTEM ARRIVING FOR THE WEEKEND.
A POSITIVELY TILTED MEAN TROUGH DEVELOPS IN THE WESTERN UNITED
STATES AND LONG RANGE MODELS ARE CONSISTENT AND CONGRUENT WITH
THIS SYNOPTIC FEATURE. THIS SETS UP A COLD AND UNSETTLED PATTERN
FOR US WITH THE SOUTHERN STREAM SOUTHWEST FLOW AND IMPULSES OF
ENERGY FROM SATURDAY THROUGH MONDAY NIGHT THAT COULD GIVE US MORE
THAN ONE ROUND OF MEASURABLE SNOWFALL. FOR NOW...THE CURRENT TRACK
WOULD PLACE MORE SNOW CHANCES IN OUR SOUTHERN CWA...BUT AS WE ALL
KNOW...THINGS MAY TREND ONE WAY OR ANOTHER...ESPECIALLY AS WE ARE
3 TO 5 DAYS AWAY. I DID BUMP UP PRECIPITATION CHANCES A BIT MORE
FOR SATURDAY AND SATURDAY NIGHT AS MODELS CONTINUE TO PAINT
CONSIDERABLE QPF FOR US...ESPECIALLY IN OUR SOUTH. THIS STILL
LOOKS AT LEAST LIKE A POTENTIAL WINTER WEATHER ADVISORY SITUATION
...BUT WE STILL HAVE SOME TIME BEFORE THIS ARRIVES AND WE SHOULD
GET A BETTER HANDLE OF THIS WITH TIME.
I WENT CLOSER TO CONSRAW FOR HIGH TEMPERATURES FRIDAY INTO MONDAY
...WHICH WAS GENERALLY PRETTY CLOSE TO SUPERBLEND...EXCEPT FOR
MONDAY WHICH BUMPED TEMPERATURES DOWN A BIT FROM INITIALIZED
GRIDS. THIS WOULD MAKE SENSE...ESPECIALLY IF THERE ENDS UP BEING
SNOW ON THE GROUND. I DO NOT SEE AN END TO WELL BELOW NORMAL
TEMPERATURES ANYTIME SOON...WITH WELL BELOW TEMPERATURES EXPECTED
INTO EARLY MARCH UNDER THIS CONSISTENTLY COLD PATTERN.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z THU MORNING)
ISSUED AT 534 AM CST WED FEB 25 2015
TODAY: MULTI-LAYERED VFR CLOUDS WILL GRADUALLY DESCEND FROM 10K FT
WITH MVFR CIGS EXPECTED BY 18Z WITH PASSAGE OF A COLD FRONT. SOME
VFR SPRINKLES...AND POSSIBLY SOME RA/SN SHWRS WILL BE POSSIBLE...
ESPECIALLY IN THE 18Z-21Z TIME FRAME. THE CERTAINTY OF PRECIP
REDUCING THE VSBY TO MVFR OR LOWER IS NOT AS HIGH AS EARLIER. SO
WHILE THERE COULD BE A BRIEF PERIOD OF MVFR/IFR SN...CONFIDENCE IS
NO LONGER HIGH ENOUGH TO HAVE A LOW VSBY IN THE TAF. WATCH FOR
POSSIBLE AMENDMENTS AS WE MONITOR RADAR TRENDS AND UPSTREAM OBS.
WINDS WILL SHIFT TO N AND GUST 35-42 KTS BEHIND THE FRONT...
ESPECIALLY AFTER 20Z. CONFIDENCE: MEDIUM
TONIGHT: STRONG N WINDS CONT BUT GRADUALLY DECREASE BEGINNING
06Z. MVFR CIGS WILL EVENTUALLY BECOME SCT. CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...HEINLEIN
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
532 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 216 AM CST WED FEB 25 2015
INITIAL CONCERN WILL BE TYPE AND EXTENT OF PRECIP AS SURFACE LOW
TRACKS ACROSS THE AREA TODAY. THEN COLD AND WINDY CONDITIONS WITH
SUBZERO WIND CHILLS APPROACHING CRITERIA THURSDAY MORNING. JUST
PLAIN COLD FRIDAY MORNING.
SURFACE LOW WAS LOCATED OVER SOUTH CENTRAL SOUTH DAKOATA AT 08Z
WITH PRIMARY BAND OF PRECIP FROM EASTERN SOUTH DAKOTA INTO
SOUTHWEST MINNESOTA AND NORTHWEST IOWA. BOTH THE HRRR AND RAP
SLOWER IN BRINGING THE PRECIP SHIELD SOUTH TODAY WITH PRIMARY BAND
STRETCHING ACROSS NORTHERN IOWA THROUGH THE MORNING. HAVE ADJUSTED
TIMING OF THE WINTER WEATHER ADVISORY TO ACCOUNT FOR THIS FEATURE
AND ALSO REMOVED THE TWO SOUTHWEST IOWA COUNTIES AS TEMPERATURES
ARE EXPECTED TO REMAIN ON THE WARM SIDE THERE FOR MOST OF THE DAY
WITH BETTER QPF EAST OF THE AREA.
HAVE TRENDED TEMPERATURES WARMER ACROSS THE SOUTH HALF OF THE AREA
AND BACKED OFF FURTHER ON PRECIP AND SNOW ACROSS THE SOUTH.
TEMPERATURES WILL BE TRICKY TODAY AND DEPEND ON TIMING OF THE COLD
AIR BEHIND THE FRONT THIS AFTERNOON AS THE LOW TRACKS ACROSS EAST
CENTRAL NEBRASKA TOWARD NORTHWEST MISSOURI. A PERIOD OF MIXED
PRECIP...WHICH COULD INCLUDE FREEZING RAIN...IS POSSIBLE FOR A
TIME THIS MORNING IN PARTS OF NORTHEAST NEBRASKA INTO WEST CENTRAL
IOWA BEFORE THE COLD AIR MOVES IN BEHIND THE FRONT. AMOUNTS SHOULD
BE LIGHT WITH LIMITED AREAL COVERAGE.
THE ARCTIC AIR SPREADS RAPIDLY SOUTH TONIGHT ALONG WITH GUSTY
NORTHWEST WINDS. SUBZERO WIND CHILLS ARE LIKELY ACROSS THE AREA BY
THURSDAY MORNING WITH NORTHERN COUNTIES APPROACHING ADVISORY
CRITERIA. WILL COVER THE COLD IN HWO FOR NOW BUT ADVISORY LOOKS
LIKELY IN LATER FORECASTS. WINDY AND COLD CONDITIONS WILL EXTEND
THROUGH THE DAY ON THURSDAY WITH WINDS DIMINISHING THURSDAY
EVENING. TEMPERATURES ARE EXPECTED TO PLUNGE BELOW ZERO THURSDAY
NIGHT AS HIGH SETTLES OVER THE AREA AND WINDS BECOME LIGHT. SLOW
WARMING???? ON FRIDAY AS HIGH MOVES EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 216 AM CST WED FEB 25 2015
LITTLE CHANGE TO GENERAL TRENDS. WEEKEND SYSTEM STILL KEEPS MAIN
PRECIP AXIS TO THE SOUTH WITH LIGHTER AMOUNTS FOR THE SOUTH HALF
OF THE CWA. MORE SIGNIFICANT SNOW POSSIBLE MONDAY INTO TUESDAY AS
MAIN WAVE COMES INTO THE PLAINS REGION.
&&
.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 524 AM CST WED FEB 25 2015
SFC CDFNT WILL MOV SOUTHEAST THRU ALL 3 TAF SITES THROUGH EARLY
AFTERNOON SWITCHING WINDS TO THE NORTH AND NORTHWEST...WITH SPEEDS
INCREASING ALONG WITH GUSTS THROUGH THE END OF THE PERIOD. BEHIND
THE COLD FRONT THERE MAY BE AN HOUR OR TWO OF -RA AT KOFK/KLNK AND
A MIX OF RA/SN AT KOMA. SOME MVFR VISBY IS POSSIBLE FOR AN HOUR OR
TWO AT KOMA WITH THE MIX. WE DO EXPECT MVFR CIGS AT ALL 3 SITES
FROM LATE MRNG THROUGH THE AFTERNOON LIFTING TO VFR OVERNIGHT.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ015-
034.
IA...WINTER WEATHER ADVISORY UNTIL 8 PM CST THIS EVENING FOR IAZ055-
056.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 8 PM CST
THIS EVENING FOR IAZ069.
&&
$$
SHORT TERM...FOBERT
LONG TERM...FOBERT
AVIATION...BOUSTEAD
AREA FORECAST DISCUSSION
NWS HASTINGS NE
505 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST WED FEB 25 2015
...ARCTIC AIR RETURNS WITH A VENGEANCE WITH FRONTAL PASSAGE
ACCOMPANIED BY POSSIBLE RAIN/SNOW SHWRS FOLLOWED BY HOWLING N
WINDS UP TO 50 MPH...
ALOFT: SEVERAL WEAK/SUBTLE SHORTWAVE TROFS WILL CROSS THE FCST
AREA THRU TONIGHT IN NW FLOW. THE LEAD TROF WILL BE THE POTENTIAL
WX- MAKER WHICH WILL MOVE THRU 15Z-00Z...ASSOCIATED WITH THE
PASSAGE OF THE SFC LOW.
SURFACE: AN ARCTIC COLD FRONT EXTENDED FROM HUDSON BAY THRU THE
GREAT LAKES ACROSS IA TO LOW PRES OVER SD AND THEN NW INTO CANADA.
THIS LOW WILL HEAD SE ACROSS NEB TODAY AND IN ITS WAKE THE FRONT
WILL SURGE S TODAY AND WILL BE S OF THE FCST AREA BY SUNSET.
ARCTIC HIGH PRES THEN BEGINS BUILDING IN TONIGHT FROM CANADA.
EARLY THIS MORNING: CLOUDS WILL CONT TO INCREASE FROM THE NW.
GENERALLY MILD WITH TEMPS AT OR ABOVE FRZG MOST LOCATIONS.
HAZARDS: N WINDS WILL GUST 45-50 MPH 12PM-12AM. DANGEROUS WIND
CHILLS DOWN TO -20F LATE TONIGHT...N OF I-80.
TODAY: NOT SURE HOW IT UNFOLDS. WE KNOW FOR SURE THAT THE
STEADIEST PRECIP WILL BE E OF THE FCST AREA...ON THE COLD SIDE OF
THE FRONT IN THE WAA. SPOTTY ECHOES HAVE BEEN INCREASE THRU THE
NIGHT SW OF THE LOW THRU THE BLACK HILLS INTO THE PANHANDLE.
UPSTREAM SOUNDINGS SHOW A LOT OF DRY AIR IN THE LOW-LVLS. SO FAR
HAVE ONLY SEEN ONE STATION REPORT SPRINKLES UPSTREAM.
OVERALL EXPECT A M/CLOUDY DAY OVER S-CNTRL NEB AND BECOMING
M/CLOUDY OVER N-CNTRL KS. MOST MESOSCALE MODELS SUGGEST A
NARROW/BROKEN BAND OF STRONGLY-FORCED SHWRS WILL DEVELOP ALONG THE
FRONT WHICH COULD BRIEFLY CHANGEOVER TO SNOW BEFORE ENDING...
PRIMARILY N OF HWY 6. PRECIP WILL INITIALLY STRUGGLE TO REACH THE
GROUND. THE ENVIRONMENT IS NOT FAVORABLE FOR MUCH MEASURABLE
PRECIP.
THE LOWEST CONFIDENCE PORTION OF THE FCST IS TEMPS. WE COULD BE
TOO COOL. MULTIPLE OVERNIGHT CYCLES OF THE RAP SUGGEST 50F UP TO
I-80 AND NEARING 60 OVER N-CNTRL KS. I COULD ONLY ENVISION THAT
HAPPENING WITH FULL SUN AND THAT IS NOT EXPECTED. USED CONSENSUS
OF HI-RES SHORT-TERM MODELS FOR HIGHS AND THEN NUDGED HIGHS MORE
INTO THE 50S OVER N-CNTRL KS IN COORDINATION WITH KS OFFICES.
TEMPS WILL FALL THIS AFTERNOON N OF I-80 BEHIND THE FRONT.
WINDS: BLENDED THE 18Z/00Z MAV MOS 50-50. N WINDS WILL HOWL...
GUSTING 45-50 MPH IN THE TIGHT PRES GRADIENT/CAA BEHIND THE LOW. 6
HR PRES RISES OF 12 MB ARE LIKELY.
TONIGHT: CLOUDY...WINDY AND TURNING VERY COLD. WINDS WILL BE
STRONGEST PRIOR TO MIDNIGHT. TEMPS PLUMMET INTO THE SINGLE DIGITS
OVER N-CNTRL NEB AND LINGERING WINDS WILL PUSH WIND CHILLS AS LOW
AS -20F.
CAA WILL RESULT IN SOME MODEST INSTABILITY IN THE LINGERING
STRATUS WHICH WILL COOL INTO THE IDEAL SNOW GROWTH LAYER. SO KEPT
THE MENTION OF FLURRIES FROM THE PREVIOUS FCST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 504 AM CST WED FEB 25 2015
THE MAIN FORECAST CONCERN IS THE CHANCE FOR SNOW OVER THE WEEKEND
AND INTO EARLY NEXT WORK WEEK.
WE START OUT THE LONG TERM FORECAST THURSDAY WITH AN EXPANDING
SURFACE RIDGE BUILDING IN. MODEL SOUNDINGS INDICATE THAT WE COULD
HANG ON TO SOME STRATUS A LITTLE LONGER THAN WHAT OUR INITIALIZED
SUPERBLEND ADVERTISES AND I HAVE BUMPED UP SKY COVER. MODELS ARE IN
GOOD AGREEMENT WITH 850 MB TEMPERATURES IN THE -165 TO -20 RANGE FOR
THURSDAY...WE WILL STRUGGLE TO GET HIGHS IN THE TEENS FOR MOST
AREAS. WE MAY MAKE IT TO AROUND 20 IN OUR SOUTH. I USED THE NAM FOR
HIGH TEMPERATURES...BUT THIS IS DEPENDING ON WIND SPEEDS STAYING UP
A BIT. GFS ACTUALLY INDICATES SOME AREA IN OUR NORTHEAST NOT
BREAKING INTO THE TEENS FOR HIGHS...AND THIS MAY VERY WELL
HAPPEN...ESPECIALLY IF WIND SPEED DROPS AND WE GET A LITTLE MORE SKY
COVER HANGING AROUND.
THE 1040 MB HIGH WILL BE CENTERED OVER THE NORTHERN PLAINS BY
THURSDAY EVENING AND WILL CONTINUE MOVING SOUTH SOUTHEAST. THURSDAY
WILL FEEL QUITE COLD. WIND CHILLS MAY BRIEFLY BREAK INTO THE SINGLE
DIGITS FOR THE AFTERNOON BEFORE MAKING ANOTHER DIVE. WIND SPEED
COULD BE JUST STRONG ENOUGH THURSDAY NIGHT TO KEEP WIND CHILLS IN
THE -15 TO -20 RANGE IN OUR NORTHEAST. WIND SPEEDS SHOULD DIMINISH
LATE AS THE CENTER OF THE SURFACE HIGH SLIDES NEARER...MAYBE AS
CLOSE AS EASTERN NEBRASKA. THIS WILL CAUSE WIND TO DROP OFF QUITE A
BIT AND WITH ANTICIPATED MOSTLY CLEAR SKY FOR MUCH OF THE CWA...WE
COULD WIND UP BEING BELOW ZERO FOR A CONSIDERABLE PORTION OF THE
CWA. ORD COULD REALLY TANK TO NEAR -10. NUMERICAL MODELS ARE ALL
TRENDING COLDER FOR THURSDAY NIGHT/FRIDAY MORNING AND I HAVE
CONTINUED THIS TREND. I BUMPED DOWN TEMPERATURES CONSIDERABLY
COMPARED TO SUPERBLEND INITIALIZATION. WE MAY HOLD NEAR ZERO IN OUR
SOUTH/SOUTHWEST WHERE WE MAY HAVE A FEW MORE CLOUDS AROUND ALONG
WITH SLIGHTLY STRONGER WIND SPEED.
NUMERICAL MODELS ALL TEND TO KEEP US DRY FRIDAY/FRIDAY NIGHT FOR THE
MOST PART...WITH THE EXCEPTION OF PERHAPS SOME FLURRIES IN ADVANCE
OF THE NEXT WINTER SYSTEM ARRIVING FOR THE WEEKEND.
A POSITIVELY TILTED MEAN TROUGH DEVELOPS IN THE WESTERN UNITED
STATES AND LONG RANGE MODELS ARE CONSISTENT AND CONGRUENT WITH THIS
SYNOPTIC FEATURE. THIS SETS UP A COLD AND UNSETTLED PATTERN FOR US
WITH THE SOUTHERN STREAM SOUTHWEST FLOW AND IMPULSES OF ENERGY FROM
SATURDAY THROUGH MONDAY NIGHT THAT COULD GIVE US MORE THAN ONE ROUND
OF MEASURABLE SNOWFALL. FOR NOW...THE CURRENT TRACK WOULD PLACE MORE
SNOW CHANCES IN OUR SOUTHERN CWA...BUT AS WE ALL KNOW...THINGS MAY
TREND ONE WAY OR ANOTHER...ESPECIALLY AS WE ARE 3 TO 5 DAYS AWAY. I
DID BUMP UP PRECIPITATION CHANCES A BIT MORE FOR SATURDAY AND
SATURDAY NIGHT AS MODELS CONTINUE TO PAINT CONSIDERABLE QPF FOR
US...ESPECIALLY IN OUR SOUTH. THIS STILL LOOKS AT LEAST LIKE A
POTENTIAL WINTER WEATHER ADVISORY SITUATION...BUT WE STILL HAVE SOME
TIME BEFORE THIS ARRIVES AND WE SHOULD GET A BETTER HANDLE OF THIS
WITH TIME.
I WENT CLOSER TO CONSRAW FOR HIGH TEMPERATURES FRIDAY INTO
MONDAY...WHICH WAS GENERALLY PRETTY CLOSE TO SUPERBLEND...EXCEPT FOR
MONDAY WHICH BUMPED TEMPERATURES DOWN A BIT FROM INITIALIZED GRIDS.
THIS WOULD MAKE SENSE...ESPECIALLY IF THERE ENDS UP BEING SNOW ON
THE GROUND. I DO NOT SEE AN END TO WELL BELOW NORMAL TEMPERATURES
ANYTIME SOON...WITH WELL BELOW TEMPERATURES EXPECTED INTO EARLY
MARCH UNDER THIS CONSISTENTLY COLD PATTERN.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z WED NIGHT)
ISSUED AT 1159 PM CST TUE FEB 24 2015
REST OF TONIGHT: MULTI-LAYERED VFR MID-LVL CIGS WILL OVERTAKE THE
TERMINALS FROM THE N...REMAINING AT OR ABOVE 10K FT. SSW WINDS
JUST UNDER 10 KTS. THERE MAY BE SOME MARGINAL LLWS BASED ON WINDS
FROM OUR RADAR AT 400 FT...BUT THESE WINDS MAY BE OVERDONE.
CONFIDENCE: HIGH
TUE: VFR CIGS LOWER TO AROUND 3500 FT. COLD FRONT PASSES THE
TERMINALS AROUND 18Z WITH A BRIEF BURST OF POSSIBLY IFR SNOW.
THERE IS UNCERTAINTY IN THE INTENSITY OF THE SNOW. IF THE WORST
CASE OCCURS...ANY ACCUM WOULD BE LESS THAN 1 INCH. MVFR CIGS MOVE
IN AFTER FRONTAL PASSAGE AND N WIND WILL GUST TO 35 KTS...WITH A
ONE-TIME PKWND OF 40 KTS POSSIBLE. CONFIDENCE: MEDIUM
TUE EVE: MVFR CIGS REMAIN. N WINDS WILL BE GRADUALLY DECREASING.
CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...HEINLEIN
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
942 AM CST WED FEB 25 2015
.UPDATE...
ISSUED AT 942 AM CST WED FEB 25 2015
LIGHT SNOW CONTINUES TO LINGER OVER THE EXTREME SE CORNER OF
NORTH DAKOTA SO KEPT LOW POPS GOING UNTIL ABOUT 18Z. WIND CHILLS
HAVE WARMED TO ABOVE ADVISORY CRITERIA AND THE ADVISORY HAS BEEN
CANCELED. OTHERWISE...REST OF FORECAST LOOKS GOOD.
UPDATE ISSUED AT 652 AM CST WED FEB 25 2015
TWEAKED POPS BASED ON CURRENT RADAR TRENDS BUT WILL CONTINUE WITH
HIGH PROBABILITIES FOR THE NEXT FEW HOURS AS SHORT RANGE MODELS ALL
HAVE LIGHT SNOW HANGING AROUND IN THE SOUTHWESTERN COUNTIES UNTIL
13 TO 14Z. ANY ADDITIONAL ACCUMULATIONS SHOULD BE MINIMAL.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
SNOW THIS MORNING AND WIND CHILLS TONIGHT WILL BE THE PRIMARY
FORECAST CHALLENGE FOR THE SHORT TERM.
NORTHWESTERLY FLOW ALOFT CONTINUES WITH A WEAK REINFORCING
SHORTWAVE DIGGING THROUGH THE DAKOTAS. THE BAND OF SNOW HAS BEEN A
BIT FURTHER EAST THAN EXPECTED...AND VALLEY CITY HAS BEEN DOWN TO
2SM WITH LIGHT SNOW AND IT LOOKS LIKE GWINNER HAS FINALLY
SATURATED AND IS GETTING SOME SNOW AT THE SFC. THE BAND MATCHES UP
WITH THE 850-700MB FRONTOGENESIS FAIRLY WELL...AND THE NAM HAS
THAT AREA STARTING TO MOVE OFF TO THE SOUTH LATER THIS MORNING.
THAT SEEMS TO FIT PRETTY WELL WITH THE RAP AND HRRR WHICH HAVE THE
QPF PEAKING AROUND 10Z AND THEN TAPERING OFF 3 TO 4 HOURS LATER.
TIME HEIGHT PLOTS FOR OUR SOUTHWESTERN CWA HAVE A GOOD OMEGA
BULLSEYE IN THE GOOD DENDRITIC GROWTH ZONE UNTIL AROUND 12Z.
CONTINUED TREND OF CATEGORICAL POPS IN THE FAR WEST FOR EARLY THIS
MORNING...WITH SOME ADJUSTMENTS FOR CURRENT RADAR TRENDS. RAP PUTS
OUT NEARLY 3 INCHES IN FAR SOUTHERN SARGENT COUNTY...BUT THIS
SEEMS A BIT HIGH GIVEN HOW LONG IT HAS TAKEN OBS SITES TO
SATURATE. CONTINUED WITH 1 TO 2 INCHES IN THE FAR SOUTHWESTERN CWA.
THE PRECIP SHOULD TAPER OFF BY MID MORNING AND WE WILL SEE
DECREASING CLOUDS MOVE SOUTH AS ARCTIC HIGH PRESSURE BUILDS INTO
THE NORTHERN PLAINS. THE HIGH WILL CONTINUE INTO TONIGHT AS THE
MAIN UPPER TROUGH CONTINUES TO DIG SOUTHEASTWARD. WITH CLEARING
SKIES AND THE COLD AIR MASS...WE SHOULD AGAIN GET DOWN TO THE -10
TO -20 RANGE TONIGHT. WINDS WILL DECREASE AS THE CENTER OF THE
HIGH MOVES DOWN INTO WESTERN ND...BUT THINK WE SHOULD HAVE ENOUGH
GRADIENT TO BRING WIND CHILLS DOWN TO ADVISORY LEVELS TONIGHT.
GIVEN THAT THERE IS A CURRENT HEADLINE FOR OUR NORTHEASTERN
COUNTIES AND WIND CHILL ADVISORIES ARE BECOMING A DIME A
DOZEN...WILL HOLD OFF ON ISSUING ONE FOR NOW. THE COLD HIGH
PRESSURE WILL REMAIN THROUGH THURSDAY WITH HIGHS JUST ABOVE ZERO.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
THURSDAY NIGHT THROUGH FRIDAY NIGHT...NORTHWESTERLY FLOW ALOFT
CONTINUES WITH THE CENTER OF THE SFC HIGH FINALLY STARTING TO MOVE
SOUTH AND EAST. WIND CHILLS COULD AGAIN BE AN ISSUE THURSDAY NIGHT
INTO FRIDAY MORNING. THE SOUTHERLY WINDS WILL INCREASE MORE ON
FRIDAY AS HIGH PULLS FURTHER AWAY. TEMPS SHOULD GET UP TO AROUND
10 BY FRIDAY AFTERNOON UNDER THE LATE WINTER SUN BUT WILL STILL BE
WELL BELOW AVERAGE AND WILL FEEL PRETTY RAW WITH THE INCREASING
WINDS. WEAK WARM AIR ADVECTION AND WINDS KEEPING US MIXED WILL
ALLOW TEMPS FRIDAY NIGHT TO FALL ONLY SLIGHTLY BELOW ZERO INSTEAD
OF THE TEENS BELOW.
SATURDAY TO WEDNESDAY...MODELS IN GOOD AGREEMENT WITH THE EXTENDED
LEADING TO HIGH CONFIDENCE FOR MUCH OF THE WEEKEND AND FIRST PART OF
NEXT WEEK. DRY WEATHER WILL CONTINUE ACROSS THE NORTHERN PLAINS WITH
THE ONLY SLGHT CHC FOR -SN BEING TUESDAY INTO WEDNESDAY FOR THE
SOUTHERN AND EASTERN PORTIONS OF THE AREA. 500MB SPLIT FLOW
CONTINUES WITH WESTERN CONUS THROUGH AMPLIFYING INTO THE FIRST PART
OF NEXT WEEK THE 500MB SW TO NE ORIENTED TROUGH AXIS PUSHES ACROSS
THE FA ON TUESDAY...BRINGING THE -SN POTENTIAL. TEMPERATURES NEAR
SEASONAL NORMALS WITH HIGHS IN THE 20S SAT-TUE WITH POST FROPA COLD
FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 652 AM CST WED FEB 25 2015
LIGHT SNOW CONTINUES TO THE SOUTHWEST OF TAF SITES...WHICH ALL
HAVE VFR CIGS IF ANY AT ALL. CIGS OF 5000-10000 FT WILL REMAIN
OVER MUCH OF THE AREA THIS MORNING BEFORE THE SYSTEM PULLS FURTHER
SOUTH AND WE BEGIN TO CLEAR OUT FOR TONIGHT. NORTHEAST WINDS WILL
SHIFT TO THE NORTH TO NORTHWEST AND INCREASE A BIT...UP TO THE 15
TO 20 KT RANGE IN PLACES. HIGH PRESSURE BUILDING IN SHOULD ALLOW
THE WINDS TO DECREASE AFTER SUNSET.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...HOPKINS
SHORT TERM...JR
LONG TERM...JR/JK
AVIATION...JR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
652 AM CST WED FEB 25 2015
.UPDATE...
ISSUED AT 652 AM CST WED FEB 25 2015
TWEAKED POPS BASED ON CURRENT RADAR TRENDS BUT WILL CONTINUE WITH
HIGH PROBABILITIES FOR THE NEXT FEW HOURS AS SHORT RANGE MODELS ALL
HAVE LIGHT SNOW HANGING AROUND IN THE SOUTHWESTERN COUNTIES UNTIL
13 TO 14Z. ANY ADDITIONAL ACCUMULATIONS SHOULD BE MINIMAL.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
SNOW THIS MORNING AND WIND CHILLS TONIGHT WILL BE THE PRIMARY
FORECAST CHALLENGE FOR THE SHORT TERM.
NORTHWESTERLY FLOW ALOFT CONTINUES WITH A WEAK REINFORCING
SHORTWAVE DIGGING THROUGH THE DAKOTAS. THE BAND OF SNOW HAS BEEN A
BIT FURTHER EAST THAN EXPECTED...AND VALLEY CITY HAS BEEN DOWN TO
2SM WITH LIGHT SNOW AND IT LOOKS LIKE GWINNER HAS FINALLY
SATURATED AND IS GETTING SOME SNOW AT THE SFC. THE BAND MATCHES UP
WITH THE 850-700MB FRONTOGENESIS FAIRLY WELL...AND THE NAM HAS
THAT AREA STARTING TO MOVE OFF TO THE SOUTH LATER THIS MORNING.
THAT SEEMS TO FIT PRETTY WELL WITH THE RAP AND HRRR WHICH HAVE THE
QPF PEAKING AROUND 10Z AND THEN TAPERING OFF 3 TO 4 HOURS LATER.
TIME HEIGHT PLOTS FOR OUR SOUTHWESTERN CWA HAVE A GOOD OMEGA
BULLSEYE IN THE GOOD DENDRITIC GROWTH ZONE UNTIL AROUND 12Z.
CONTINUED TREND OF CATEGORICAL POPS IN THE FAR WEST FOR EARLY THIS
MORNING...WITH SOME ADJUSTMENTS FOR CURRENT RADAR TRENDS. RAP PUTS
OUT NEARLY 3 INCHES IN FAR SOUTHERN SARGENT COUNTY...BUT THIS
SEEMS A BIT HIGH GIVEN HOW LONG IT HAS TAKEN OBS SITES TO
SATURATE. CONTINUED WITH 1 TO 2 INCHES IN THE FAR SOUTHWESTERN CWA.
THE PRECIP SHOULD TAPER OFF BY MID MORNING AND WE WILL SEE
DECREASING CLOUDS MOVE SOUTH AS ARCTIC HIGH PRESSURE BUILDS INTO
THE NORTHERN PLAINS. THE HIGH WILL CONTINUE INTO TONIGHT AS THE
MAIN UPPER TROUGH CONTINUES TO DIG SOUTHEASTWARD. WITH CLEARING
SKIES AND THE COLD AIR MASS...WE SHOULD AGAIN GET DOWN TO THE -10
TO -20 RANGE TONIGHT. WINDS WILL DECREASE AS THE CENTER OF THE
HIGH MOVES DOWN INTO WESTERN ND...BUT THINK WE SHOULD HAVE ENOUGH
GRADIENT TO BRING WIND CHILLS DOWN TO ADVISORY LEVELS TONIGHT.
GIVEN THAT THERE IS A CURRENT HEADLINE FOR OUR NORTHEASTERN
COUNTIES AND WIND CHILL ADVISORIES ARE BECOMING A DIME A
DOZEN...WILL HOLD OFF ON ISSUING ONE FOR NOW. THE COLD HIGH
PRESSURE WILL REMAIN THROUGH THURSDAY WITH HIGHS JUST ABOVE ZERO.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
THURSDAY NIGHT THROUGH FRIDAY NIGHT...NORTHWESTERLY FLOW ALOFT
CONTINUES WITH THE CENTER OF THE SFC HIGH FINALLY STARTING TO MOVE
SOUTH AND EAST. WIND CHILLS COULD AGAIN BE AN ISSUE THURSDAY NIGHT
INTO FRIDAY MORNING. THE SOUTHERLY WINDS WILL INCREASE MORE ON
FRIDAY AS HIGH PULLS FURTHER AWAY. TEMPS SHOULD GET UP TO AROUND
10 BY FRIDAY AFTERNOON UNDER THE LATE WINTER SUN BUT WILL STILL BE
WELL BELOW AVERAGE AND WILL FEEL PRETTY RAW WITH THE INCREASING
WINDS. WEAK WARM AIR ADVECTION AND WINDS KEEPING US MIXED WILL
ALLOW TEMPS FRIDAY NIGHT TO FALL ONLY SLIGHTLY BELOW ZERO INSTEAD
OF THE TEENS BELOW.
SATURDAY TO WEDNESDAY...MODELS IN GOOD AGREEMENT WITH THE EXTENDED
LEADING TO HIGH CONFIDENCE FOR MUCH OF THE WEEKEND AND FIRST PART OF
NEXT WEEK. DRY WEATHER WILL CONTINUE ACROSS THE NORTHERN PLAINS WITH
THE ONLY SLGHT CHC FOR -SN BEING TUESDAY INTO WEDNESDAY FOR THE
SOUTHERN AND EASTERN PORTIONS OF THE AREA. 500MB SPLIT FLOW
CONTINUES WITH WESTERN CONUS THROUGH AMPLIFYING INTO THE FIRST PART
OF NEXT WEEK THE 500MB SW TO NE ORIENTED TROUGH AXIS PUSHES ACROSS
THE FA ON TUESDAY...BRINGING THE -SN POTENTIAL. TEMPERATURES NEAR
SEASONAL NORMALS WITH HIGHS IN THE 20S SAT-TUE WITH POST FROPA COLD
FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 652 AM CST WED FEB 25 2015
LIGHT SNOW CONTINUES TO THE SOUTHWEST OF TAF SITES...WHICH ALL
HAVE VFR CIGS IF ANY AT ALL. CIGS OF 5000-10000 FT WILL REMAIN
OVER MUCH OF THE AREA THIS MORNING BEFORE THE SYSTEM PULLS FURTHER
SOUTH AND WE BEGIN TO CLEAR OUT FOR TONIGHT. NORTHEAST WINDS WILL
SHIFT TO THE NORTH TO NORTHWEST AND INCREASE A BIT...UP TO THE 15
TO 20 KT RANGE IN PLACES. HIGH PRESSURE BUILDING IN SHOULD ALLOW
THE WINDS TO DECREASE AFTER SUNSET.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...WIND CHILL ADVISORY UNTIL 10 AM CST THIS MORNING FOR MNZ005-006-
008-009.
&&
$$
UPDATE...JR
SHORT TERM...JR
LONG TERM...JR/JK
AVIATION...JR
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
1034 AM EST WED FEB 25 2015
.DISCUSSION...
THE FORECAST APPEARS ON TRACK...WITH NO INDICATIONS OF MAJOR
CHANGES BASED ON THE LATEST OBSERVED AND MODEL DATA. THE HRRR SEEMS
TO BE DOING WELL IN DEPICTING THE PRECIP OVER AL AND MS. SOME
EVAPORATION INTO A LOW LEVEL DRY LAYER WILL DELAY PRECIP AT THE
GROUND...WITH THE CHA AREA EXPECTED TO SEE SNOW BEGIN IN THE 20-22Z
WINDOW. STRONG VERTICAL ASCENT ASSOCIATED WITH AGEOSTROPHIC FORCING
COULD BRING A PERIOD OF HEAVY SNOW IN SOUTHERN AREAS AROUND 00Z.
EXPECT THAT TIMING AROUND KNOXVILLE AND OAK RIDGE WILL BE
22-00Z...WITH TRI-CITIES AND SW VA APPROXIMATELY BETWEEN 00Z-02Z.
THE WINDOW FOR HEAVY SNOW IS NOT OPEN FOR LONG...AS MIDLEVEL
MOISTURE IN THE DENDRITE GROWTH ZONE BEGINS TO DISAPPEAR IN THE
04-08Z TIME FRAME.
FORECAST SNOW AMOUNTS ARE IN LINE WITH THE LATEST SREF...BUT A
LITTLE LOW IN SOME SPOTS COMPARED TO THE LATEST NAM...WHICH SPREADS
3+ INCH AMOUNTS ALL THE WAY INTO THE PLATEAU. THE HRRR IS ON THE
OTHER END OF THE SPECTRUM...SHOWING VERY LITTLE SNOW WEST OF OAK
RIDGE. THE NAM IS AN OUTLIER...BUT IT IS NOTABLE THAT THERE IS A
CLUSTER OF SREF MEMBERS THAT SHOW SNOW ACCUMULATION SEVERAL INCHES
ABOVE THE SREF MEAN.
WILL KEEP SNOW AMOUNTS AND THE WARNING/ADVISORY AREAS UNCHANGED
FOR THE UPDATE. TEMPERATURES WILL NEED SOME DOWNWARD ADJUSTMENTS
AS OBS ARE RUNNING LOWER THAN FORECAST IN SEVERAL SPOTS.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 7 AM EST
THURSDAY FOR CHEROKEE-CLAY.
TN...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 7 AM EST
THURSDAY FOR BLOUNT SMOKY MOUNTAINS-COCKE SMOKY MOUNTAINS-
JOHNSON-SEVIER SMOKY MOUNTAINS-SOUTHEAST CARTER-SOUTHEAST
GREENE-SOUTHEAST MONROE-UNICOI.
WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON
TO 7 AM EST /6 AM CST/ THURSDAY FOR ANDERSON-BLEDSOE-
CAMPBELL-CLAIBORNE-GRAINGER-HAMBLEN-HANCOCK-HAWKINS-
JEFFERSON-KNOX-LOUDON-MORGAN-NW BLOUNT-NORTH SEVIER-
NORTHWEST CARTER-NORTHWEST COCKE-NORTHWEST GREENE-RHEA-
ROANE-SCOTT TN-SULLIVAN-UNION-WASHINGTON TN.
WINTER STORM WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY FOR
BRADLEY-EAST POLK-HAMILTON-MARION-MCMINN-MEIGS-NORTHWEST
MONROE-SEQUATCHIE-WEST POLK.
VA...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM EST
THURSDAY FOR LEE-RUSSELL-SCOTT-WASHINGTON-WISE.
&&
$$
DGS
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
353 AM MST WED FEB 25 2015
.SYNOPSIS...
UPPER LOW WHICH BROUGHT WIND AND SHOWERS TO THE AREA TUESDAY HAS NOW
MOVED EAST OF THE AREA TO BE REPLACED BY DRIER NORTHWEST FLOW.
TEMPERATURES TODAY WILL REMAIN NEAR NORMAL. ANOTHER COLD FRONT MOVES
IN FROM THE EAST ON THURSDAY TO GIVE US A COUPLE OF COOL DAYS. THE
FRONT COULD ALSO PRODUCE SOME LIGHT SNOW OVER THE SACRAMENTO
MOUNTAINS. AN UPPER LEVEL LOW WILL DROP TO THE GREAT BASIN SATURDAY
AND THEN OVER ARIZONA ON MONDAY. THIS WILL BRING MORE MOISTURE TO
THE AREA WITH A CHANCE OF SHOWERS...MAINLY SATURDAY THROUGH TUESDAY.
TEMPERATURES WILL WARM BACK TO AROUND NORMAL.
&&
.DISCUSSION...
UPPER LOW WHICH BROUGHT US OUR WIND AND SHOWERS ON TUESDAY HAS NOW
MOVED OVER THE TEXAS PANHANDLE. VERY FEW CLOUDS LEFT OTHER THAN A
FEW SCRAPS OVER HUDSPETH COUNTY. AREAS WEST OF THE RIO GRANDE VALLEY
HAVE HAD GOOD RADIATIONAL COOLING FOR SEVERAL HOURS. HRRR SHOWS
WINDS AND DEWPOINT DEPRESSIONS CONDUCIVE TO SOME FOG OVER THE NEXT
SEVERAL HOURS SO MENTIONED PATCHY FOG/FREEZING FOG FOR THE LOWLAND
ZONES WEST OF EL PASO THIS MORNING. BELIEVE WEST TEXAS ZONES HAVE
NOT HAD AS LONG OF RADIATIONAL COOLING SO LEFT FOG MENTION OUT OF
THOSE ZONES.
NEXT FEATURE TO WATCH IS THE BACKDOOR COLD FRONT PUSHING IN ON
THURSDAY IN RESPONSE TO A SHORT WAVE MOVING DOWN IN THE NORTHWEST
FLOW ALOFT. SOME EASTERLY SURGE MOVES IN ALREADY LATE TONIGHT BUT
THE MAIN COLD FRONT REACHES THE SACRAMENTO MOUNTAINS THURSDAY MID
MORNING. EXPECT SOME UPSLOPE LIGHT SNOW WITH THIS OVER THE SACS.
TEMPERATURES WILL COOL MOST OF THE CWA AS THE FRONT REACHES WEST TO
AT LEAST THE CONT DIVIDE. BOTH GFS/NAM SHOW VORT CENTER DROPPING
DOWN OVER CENTRAL NEW MEXICO FRIDAY AFTERNOON AND PERHAPS ENHANCING
MORE SIGNIFICANT SNOWFALL FOR THE SACS...THOUGH LIKELY ADVISORY TYPE
SNOW ACCUMULATIONS AT BEST. TEMPS THURSDAY/FRIDAY TO FALL BACK BELOW
NORMAL.
WEEKEND AND FIRST PART OF NEXT WEEK STILL LOOKING UNSETTLED AND
MODELS NOT EXACTLY DOING BANG UP JOB OF REACHING CONSENSUS. GFS FOR
SEVERAL RUNS NOW HAS BEEN QUITE BULLISH ON DROPPING NEXT POSITIVELY
TILTED TROUGH SOUTHWARD AND CLOSING LOW OFF OVER THE GREAT
BASIN...EVENTUALLY BRING LOW OVER ARIZONA AND TAPPING INTO SOME SUB
TROPICAL MOISTURE. ECMWF HAS BEEN MORE BEARISH...BARELY CLOSING OFF
A LOW IF AT ALL...AND MOVING SYSTEM ACROSS NEW MEXICO AS AN OPEN
TROUGH. QUICK LOOK AT 06Z GFS RUN NOW SHOWS IT STARTING TO RESEMBLE
THE ECMWF. GRIDS/FORECAST FOR NOW GOING A BIT MORE WITH THE BULLISH
GFS SOLUTION. MOISTURE TAP AND LOW SHOULD START PRODUCING SOME
SHOWERS WESTERN ZONES ON SATURDAY AND SLOWLY SPREADING THE SHOWERS
EASTWARD...TO INCLUDE THE EASTERN ZONES BY SUNDAY NIGHT OR MONDAY.
SNOW LEVELS START OUT HIGH...AT 8000 FT OR HIGHER BUT GRADUALLY
LOWER SUNDAY NIGHT AND MONDAY AS PACIFIC COLD FRONT APPROACHES. GFS
CONTINUES TO SHOW HEAVY SNOW POTENTIAL FOR THE GILA/BLACK RANGE
MOUNTAINS. HOPE MODELS CONVERGE ON THE SOLUTION SOON!
&&
.AVIATION...VALID 25/12Z-26/12Z...
VFR EXPECTED AT ALL TERMINALS THRU THE PERIOD. P6SM SKC INITIALLY
WITH FEW-SCT250 EXPECTED AFTER 00Z. SFC WINDS PRIMARILY FROM THE
WEST AT SPEEDS OF 12 KTS OR LESS WITH GUSTS 15-20 KTS POSSIBLE
BETWEEN 18Z AND 00Z.
&&
.FIRE WEATHER...
DRIER NORTHWEST FLOW HAS SETTLED ACROSS THE REGION AS AN UPPER LEVEL
LOW CONTINUES TO MOVE OFF TO THE EAST. EXPECT MOSTLY CLEAR SKIES
TODAY WITH AFTERNOON TEMPS RETURNING TO NEAR NORMAL. THIS WILL
RESULT IN MIN RH VALUES DROPPING TO BETWEEN 15 AND 20 PERCENT FOR
MOST LOWLAND LOCATIONS WITH SLIGHTLY HIGHER READINGS ACROSS THE
HIGHER TERRAIN. 20 FOOT WINDS WILL PICK UP AGAIN FROM THE WEST
DURING THE AFTERNOON HELPING LIFT VENT RATES INTO THE GOOD TO VERY
GOOD RANGE ACROSS THE REGION.
ANOTHER PAIR OF WEAK UPPER DISTURBANCES WILL CLIP THE AREA THURSDAY
AND FRIDAY WITH ANOTHER BACK DOOR COLD FRONT TO MOVING INTO THE
AREA EARLY THURSDAY. WHILE THE BEST CHANCES FOR WETTING PRECIP WILL
REMAIN TO OUR NORTH THERE IS A SLIGHT CHANCE FOR SOME RAIN AND SNOW
OVER THE SACRAMENTO MOUNTAINS DURING THIS TIME FRAME. WE WILL ALSO
SEE MIN RH VALUES INCREASE BY 15 TO 20 PERCENT ACROSS THE REGION AS
EASTERLY BREEZES BRING IN COOLER AIR AT THE SURFACE. THIS WILL BE
FOLLOWED BY ANOTHER WARM UP OVER THE WEEKEND BEFORE A STRONGER STORM
DELIVERS MORE MORE WIND AND A BETTER CHANCE FOR WETTING PRECIP FOR
THE EARLY PART OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
EL PASO 63 39 58 33 53 / 0 0 0 0 0
SIERRA BLANCA 60 34 49 25 47 / 0 0 0 0 0
LAS CRUCES 62 34 56 31 53 / 0 0 0 0 0
ALAMOGORDO 55 32 50 30 48 / 0 0 0 10 0
CLOUDCROFT 40 20 35 22 32 / 0 0 20 30 10
TRUTH OR CONSEQUENCES 60 34 54 32 50 / 0 0 0 0 0
SILVER CITY 53 32 53 34 49 / 0 0 0 0 0
DEMING 62 32 59 30 57 / 0 0 0 0 0
LORDSBURG 61 31 60 30 58 / 0 0 0 0 0
WEST EL PASO METRO 63 38 57 35 53 / 0 0 0 0 0
DELL CITY 58 31 51 23 44 / 0 0 0 0 10
FORT HANCOCK 64 38 57 33 52 / 0 0 0 0 0
LOMA LINDA 55 35 48 31 44 / 0 0 0 0 0
FABENS 63 36 57 31 54 / 0 0 0 0 0
SANTA TERESA 63 35 56 31 53 / 0 0 0 0 0
WHITE SANDS HQ 60 36 53 31 49 / 0 0 0 0 0
JORNADA RANGE 60 28 54 26 51 / 0 0 0 0 0
HATCH 63 32 58 29 55 / 0 0 0 0 0
COLUMBUS 62 37 60 35 58 / 0 0 0 0 0
OROGRANDE 57 36 52 31 47 / 0 0 0 0 0
MAYHILL 47 24 35 22 32 / 0 0 20 30 20
MESCALERO 45 24 39 23 36 / 0 0 20 30 20
TIMBERON 46 25 39 24 34 / 0 0 10 20 10
WINSTON 52 28 49 32 44 / 0 0 0 10 0
HILLSBORO 57 34 52 34 48 / 0 0 0 0 0
SPACEPORT 60 30 55 28 51 / 0 0 0 0 0
LAKE ROBERTS 52 28 51 32 47 / 0 0 0 0 0
HURLEY 54 32 54 31 50 / 0 0 0 0 0
CLIFF 58 22 58 25 56 / 0 0 0 0 0
MULE CREEK 55 19 55 24 51 / 0 0 0 0 0
FAYWOOD 55 34 54 33 49 / 0 0 0 0 0
ANIMAS 64 33 63 31 60 / 0 0 0 0 0
HACHITA 63 31 62 29 59 / 0 0 0 0 0
ANTELOPE WELLS 65 32 65 32 62 / 0 0 0 0 0
CLOVERDALE 61 34 61 38 58 / 0 0 0 0 0
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
HEFNER/LANEY
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
522 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CST WED FEB 25 2015
MAIN FCST CONCERNS THIS PERIOD...SNOW CHANCES/AMOUNTS/NEEDED
HEADLINES ACROSS THE SOUTHWEST SIDE OF THE FCST AREA TODAY INTO
THIS EVENING...LOWS/WIND CHILLS LATER TONIGHT.
06Z DATA ANALYSIS HAD A WEAK RIDGE OF HIGH PRESSURE FROM MAN TO
IA/IL AND LOW PRESSURE DEEPENING INTO WESTERN SD. SHORTWAVE ENERGY
OF CONCERN FOR TODAY COULD BE SEEN IN WV IMAGERY DROPPING SOUTHEAST
ACROSS SOUTHERN SASKAT/ALB. SKIES REMAINED GENERALLY CLEAR ACROSS WI
WHILE CLOUDS AHEAD OF THE LOW/SHORTWAVE WERE QUICKLY SPREADING
ACROSS IA/MN. INCREASING FORCING/LIFT AHEAD OF THE LOW/SHORTWAVE WAS
PRODUCING AND INCREASING AREA OF SNOW ACROSS CENTRAL/SOUTHERN ND AND
EASTERN SD...HEADING SOUTHEAST TOWARD THE FCST AREA.
25.00Z MODELS INITIALIZED WELL...EXCEPT GFS ABOUT 5F TOO HIGH ON SFC
DEW POINTS ACROSS MUCH OF MN/IA/WI. MODELS OFFERING A TIGHTENING AND
STRONGER CONSENSUS AS THE SASKAT/ALB SHORTWAVE ENERGY DIVES
SOUTHEAST TOWARD IA TODAY THEN THIS ENERGY AND A SECONDARY NORTHERN
STREAM WAVE CARVE OUT RATHER STRONG MID LEVEL TROUGHING OVER THE
UPPER MIDWEST TONIGHT. SOME DETAIL DIFFERENCES WITH THE SHORTWAVE
ENERGY TODAY BUT END RESULT IS A STRONGER ROUND OF FORCING/LIFT TO
SPREAD ACROSS THE SOUTHWEST HALF OF THE REGION TODAY INTO THIS
EVENING. SHORT-TERM FCST CONFIDENCE IS GOOD THIS CYCLE.
FOR THE SHORT TERM...STRONGER TREND OF THE MODELS SPREADS A STRONGER
ROUND OF LOWER LEVEL THERMO-DYNAMIC FORCING WITH RATHER IMPRESSIVE
850-700MB FN/QG/QN CONVERGENCE/LIFT TO NOW CLIP THE SOUTHWEST END OF
THE FCST AREA TODAY. THIS UNDER FAVORABLE DIVERGENCE ALOFT AHEAD OF
THE SHORTWAVE TROUGH AND RIGHT ENTRANCE REGION OF A 300MB JET MAX
OVER THE GREAT LAKES. MODEL SOUNDINGS SHOWING A RATHER DEEP
DENDRITIC GROWTH ZONE FROM THE SFC-600MB OVER MUCH OF THE FCST AREA
LATER THIS MORNING AND AFTERNOON WHEN THE MAX FORCING/LIFT COME
ACROSS. QUESTION REMAINS NORTHEASTWARD EXTENT OF LOWER LEVEL
SATURATION AS INITIALLY A DRY SFC-700MB AIRMASS IS IN PLACE ACROSS
THE FCST AREA. WITH THE STRONGER LIFT AND NORTHWARD SHIFT OF THE
MODEL FORCING...CONSENSUS NOW SATURATES THE COLUMN ACROSS ROUGHLY
THE SOUTHWEST 2/3 OF THE FCST AREA TODAY INTO THIS EVENING...WITH
WHAT LOOKS TO BE SOME HIGH SNOW-WATER RATIOS /AROUND 20 TO 1/ OVER
THE SOUTHWEST END OF THE FCST AREA. SEVERAL OF THE HIGH-RES MODELS
NOW PRODUCE A SWATH OF 4 TO AS MUCH AS 12 INCHES OF SNOW ACROSS
SOUTHWEST MN TO EASTERN IA. HAVE RAISED SNOW CHANCES TO 70-100
PERCENT AND AMOUNTS ACROSS THE SOUTHWEST 2/3 OF THE FCST AREA FOR
TODAY INTO THIS EVENING. WITH THE CONSENSUS SHIFT NORTH AND HIGHER
SNOW AMOUNTS WILL ISSUE A WINTER WEATHER ADVISORY FOR MUCH OF
NORTHEAST IA FOR 15Z-03Z. DAY CREW WILL HAVE TO KEEP A CLOSE WATCH
ON EVOLUTION OF THE PRECIP/SNOW TRENDS ON WSR-88D/S. IF STRONGER/
MORE NORTH OF THE HIGH-RES WRF MODELS ARE CORRECT...ADVISORY MAY
HAVE TO BE EXPANDED EVEN FURTHER NORTH WITH POTENTIAL WINTER STORM
WARNING ALONG/SOUTH OF A ST. ANSGAR TO KOLZ IA LINE.
ANOTHER ROUND OF LOW LEVEL COLD ADVECTION SPREADS ACROSS THE AREA
TONIGHT WITH 925MB TEMPS IN THE -18C TO -22C RANGE BY 12Z THU. LOWS
HEAD TO NEAR/BELOW ZERO BUT SFC WINDS ON THE LIGHTER SIDE WITH A
WEAKER PRESSURE GRADIENT OVER THE AREA. ANY NEED FOR A WIND CHILL
ADVISORY LATE TONIGHT INTO THU MORNING APPEARS MARGINAL AT THIS
TIME WITH MINIMUM WIND CHILLS IN THE -15 TO AROUND -20. WILL LEAVE
ANY WIND CHILL ADVISORY DECISIONS TO DAY CREW. USED A BLEND OF THE
GUIDANCE HIGHS/LOWS FOR TODAY/TONIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 320 AM CST WED FEB 25 2015
MAIN FCST CONCERNS FOR THU THRU FRI NIGHT...CONTINUED COLD AND WELL
BELOW NORMAL TEMPERATURES.
25.00Z MODELS IN GOOD AGREEMENT FOR COLD MID LEVEL TROUGHING TO BE
OVER THE UPPER MIDWEST FOR THU THRU FRI NIGHT. HGTS PROGGED TO
SLOWLY RISE THRU THE PERIOD...BUT CONSENSUS IS FOR CAN/ARCTIC SFC
HIGH PRESSURE TO BE OVER THE REGION THIS PERIOD. FCST CONFIDENCE FOR
THIS PERIOD IS GOOD THIS CYCLE.
THU THRU FRI NIGHT CONTINUES TREND AS A COLD...DRY PERIOD AS THE
CENTER OF CAN/ARCTIC HIGH PRESSURE NEAR THE SASKAT/ND BORDER AT 12Z
THU DRIFTS SOUTHEAST TO OH VALLEY THRU 12Z SAT. PRESSURE GRADIENT IS
GENERALLY WEAK OVER THE AREA THRU THE PERIOD FOR LIGHTER WINDS. SOME
OF THE WEAKER/LIGHTER WINDS OVER THE AREA THU NIGHT WITH THE RIDGE
AXIS NEARBY. OVER FRESH SNOW COVER...ESPECIALLY THE SOUTHWEST 1/2 OF
THE FCST AREA...LOWS THU NIGHT TRENDING TO BE MOSTLY IN THE -10F TO
-15F RANGE...WITH SOME -15F TO -25F LOWS IN THE LOW LAYING AREAS
WHERE WINDS DECOUPLE/GO CALM. SLOW WARMUP FRI/FRI NIGHT AS THE
COLDEST CORE OF 925-850MB AIR SHIFTS SOUTHEAST OF THE FCST AREA.
WITH LITTLE CHANGE OF THE BOUNDARY LAYER AIRMASS AND LIGHT WINDS...
TEMPERATURES FRI/FRI NIGHT LOOKING TO REMAIN AROUND 20 DEGREES BELOW
NORMAL. USED A BLEND OF THE GUIDANCE HIGHS/LOWS FOR THU/FRI/FRI
NIGHT WHILE TRENDING TOWARD COLDER OF GUIDANCE FOR LOWS THU NIGHT.
FOR SATURDAY THRU TUESDAY...DAYS 4 TO 7...
MAIN FCST CONCERNS THIS PERIOD...SNOW CHANCES SAT NIGHT/SUN AND
AGAIN MON NIGHT/TUE...TEMPERATURES.
25.00Z MEDIUM RANGE MODEL RUNS CONTINUE TO ADVERTISE A PATTERN
CHANGE TOWARD MORE WESTERN CONUS TROUGHING AND RISING HGTS OVER
EASTERN NOAM IN THE SAT THRU TUE PERIOD. RATHER TIGHT MODEL
CONSENSUS ON THE DETAILS FOR SAT INTO SUN...BUT SOME SLIPPAGE OF RUN-
TO-RUN CONSISTENCY BY SUNDAY. REASONABLE CONSENSUS ON THE LONGWAVE
DETAILS OF STRONGER WESTERN NOAM TROUGHING EARLY NEXT WEEK BUT
PLENTY OF DETAIL DIFFERENCES ON TIMING/STRENGTH OF SHORTWAVES THRU
THIS FLOW. OVERALL FCST CONFIDENCE IS AVERAGE TO GOOD SAT/SUN THEN
AVERAGE TO BELOW FOR MON/TUE.
FIRST THING THE PATTERN SHIFT DOES IS ALLOW FOR MORE WESTERLY FLOW
INTO THE REGION AND THE ARCTIC AIRMASS TO BE PUSHED OUT OF THE
REGION. TEMP FOR THE WEEKEND INTO EARLY NEXT WEEK LOOK TO WARM MORE
INTO THE 5F TO 10F BELOW NORMAL RANGE VS. THE 20 TO 30 DEGREES BELOW
NORMAL THAT IS HAS BEEN MUCH OF THE PAST 2 WEEKS. TREND IS TOWARD
MORE OF A NORTHERN-SOUTHERN STREAM SPLIT FLOW OVER THE AREA FOR THE
WEEKEND...WITH THE CENTRAL/NORTHERN PARTS OF THE REGION MORE UNDER
THE NORTHERN STREAM. WHAT APPEARED LIKE IT WOULD BE A STORM SYSTEM
TO IMPACT THE FCST AREA SAT NIGHT/SUN CONTINUES TO SHIFT SOUTHWARD
WITH MORE DOMINANCE OF THE NORTHERN STREAM OVER THE AREA. SOME
RESIDUAL SMALL -SN CHANCES SAT/NIGHT SUN REMAIN AND THESE OKAY FOR
NOW BUT AGAIN MORE SIGNIFICANT ACCUMULATING SNOW THESE PERIODS HAS
TRENDED INTO IL/SOUTHERN IA. MODIFIED PACIFIC/CAN HIGH STILL SLATED
TO DRIFT ACROSS THE REGION SUN NIGHT MON. SIGNAL FOR A STRONGER
PIECE OF ENERGY TO LIFT OUT OF THE WESTERN TROUGH AND IMPACT THE
UPPER MIDWEST MON NIGHT/TUE. RUN-TO-RUN CONSISTENCY ON THIS DAY 6 TO
7 FEATURE IS WEAK YET...BUT TRENDS OF THE 25.00Z GFS/ECMWF WOULD
SPREAD A CHANCE OF ACCUMULATING SNOWS ACROSS THE AREA MON NIGHT/TUE.
FOR NOW STAYED WITH THE MODEL/ENSEMBLE CONSENSUS THESE PERIODS.
MODEL/ENSEMBLE CONSENSUS OF HIGHS/LOWS FOR SAT THRU MON ALSO LOOKS
GOOD FOR NOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 522 AM CST WED FEB 25 2015
REGIONAL RADARS INDICATE AN AREA OF LIGHT SNOW WAS ADVANCING EAST
ACROSS SOUTHERN MINNESOTA IN ASSOCIATION WITH A SURFACE LOW OVER
NORTHEAST NEBRASKA. ALL THIS ACTIVITY WAS BEING DRIVING BY A SHORT
WAVE TROUGH OVER WESTERN SOUTH DAKOTA. THE MODEL TRENDS HAVE BEEN
FOR THIS SYSTEM TO COME A LITTLE FARTHER NORTH CAUSING THE SNOW
BAND TO SHIFT TO THE NORTH AS WELL. THE 25.06Z NAM SUGGESTS THE
SURFACE LOW WILL TRACK INTO SOUTHERN IOWA TODAY WITH THE SNOW BAND
EXTENDING UP INTO SOUTHERN MINNESOTA AND WISCONSIN. BASED ON THE
TRENDS SHOWN BY THE NAM AND THE 25.10Z RAP AND HRRR...EXPECT THE
LIGHT SNOW TO MOVE INTO BOTH TAF SITES OVER THE LAST HALF OF THE
MORNING AND BASED ON UP STREAM OBSERVATIONS...THE VISIBILITY
SHOULD QUICKLY GO DOWN TO IFR WITH THE CEILINGS COMING DOWN TO
MVFR. WITH THE RAPID MOVEMENT OF THIS SYSTEM...THE SNOW SHOULD
START TO MOVE OUT OF KRST BY MID AFTERNOON AND AROUND SUNSET FOR
KLSE. A SHORT PERIOD OF MVFR VISIBILITY EXPECTED ON THE BACK EDGE
OF THE SNOW BEFORE IT COMPLETELY ENDS...HOWEVER...ENOUGH LOW LEVEL
MOISTURE TO KEEP THE CEILINGS MVFR UNTIL THE OVERNIGHT HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 9 PM CST THIS
EVENING FOR IAZ008-009-018-019-029-030.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...04
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
957 AM MST WED FEB 25 2015
.UPDATE...
ISSUED AT 945 AM MST WED FEB 25 2015
STRONG NORTHEAST WINDS ALREADY HAVE MOVED INTO DENVER A SHORT TIME
AGO SO HAVE SPED UP THE TIMING BY 2-3 HOURS REGARDING THE ONSET OF
PRECIPITATION. HIGHS LIKELY HAVE BEEN MET OR WILL BE MET SHORTLY
THEN SHOULD SEE THEM DROP INTO THE 30S THIS AFTERNOON. STILL SOME
QUESTION REGARDING THE AMOUNT OF SNOW FOR DENVER...THE ADVISORY
MAY NEED TO BE UPGRADED CLOSER TO THE FOOTHILLS AND PALMER DIVIDE
BUT STILL NOT SURE AT THIS TIME...WL SEE HOW THINGS DEVELOP THIS
AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 424 AM MST WED FEB 25 2015
A STREAK OF DIFFICULT FORECASTS REMAINS IN TACT. A LOT GOING ON
THIS AFTERNOON AND EVENING...AND AGAIN POTENTIAL OF CONVECTION
THROWS A LOT OF VARIABILITY INTO MODEL OUTPUT AND FORECAST
CONFIDENCE FOR SNOWFALL AMOUNTS IN ANY PARTICULAR AREA.
HERE IS WHERE WE ARE...LIGHT SNOW IS OCCURRING IN THE MOUNTAINS
EARLY THIS MORNING BUT THIS SHOULD DECREASE AS SOME DRIER AIR
ALOFT WORKS ACROSS THE AREA THIS MORNING. ON THE PLAINS...WE
SHOULD SEE A FEW RAIN/SNOW SHOWERS SPREADING SOUTHEAST EARLY THIS
MORNING...MAINLY EAST OF A GREELEY TO LIMON LINE. CANT EVEN RULE
OUT A BIT OF FREEZING VERY LIGHT RAIN/SPRINKLES AS A FEW VALLEY
LOCATIONS MAY HOVER JUST BELOW FREEZING AS LIGHT PRECIP BEGINS.
CLOSER TO THE FRONT RANGE...OCCASIONAL GUSTY CHINOOK WINDS BUT
WARM TEMPERATURES WILL REMAIN IN PLACE...AND ENOUGH DOWNSLOPE TO
HAVE SOME BREAKS IN THE CLOUDS.
MAIN FORECAST ATTENTION TURNS TOWARD STRONG COLD FRONT ACROSS THE
PLAINS...WHICH IS ON TIME TO PUSH THROUGH BETWEEN 1 AND 3 PM.
TEMPERATURES WILL DROP BEHIND THE FRONT WITH ANTICYCLONIC UPSLOPE
DEEPENING. UPSTREAM MOISTURE SEEMS PLENTIFUL BASED ON REAL OBS AND
PRECIPITATION OCCURRING TO OUR NORTH. LAPSE RATES BECOME MORE
UNSTABLE...ESPECIALLY IN THE NAM WHERE SOME CAPE IS
INDICATED...WHILE GFS IS SLIGHTLY MORE STABLE. THE NAM...AS WELL
AS SEVERAL MESOSCALE MODELS INCLUDING THE NMM...ARW...AND THE
FINAL HOURS OF THE RAP AND HRRR INDICATE CONVECTION BLOSSOMING
WITH 2 INCH PER HOUR SNOW RATES. BUT THEY ALSO CONFINE THEM TO
AREAS VERY CLOSE TO THE FOOTHILLS...WHICH SEEMS POSSIBLE
CONSIDERING THE STRENGTH OF NORTH/NORTHEAST FLOW. IF THIS VERIFIES
THEN HEAVIER SNOW WOULD CERTAINLY BE MORE FOCUSED TOWARD THE
FOOTHILLS...AND MUCH LESS POTENTIAL FOR MUCH ACCUMULATION TOWARD
FORT COLLINS...GREELEY...AND POINTS JUST EAST OF DENVER. WE HAVE
TRENDED FORECASTS IN THIS DIRECTION SINCE THE STRONGER NORTHERLY
FLOW USUALLY SHUTS THOSE AREAS DOWN PRETTY QUICKLY...AND DRIER LOW
LEVEL AIR WITH COLDER ARCTIC AIR THIS EVENING WOULD HAVE A
TENDENCY TO DO THE SAME.
AT THE SAME TIME...THAT ALSO FOCUSES THE HEAVIER PRECIPITATION
TOWARD THE FOOTHILLS SO HAVE OPTED TO ISSUE WINTER STORM WARNINGS
FOR FOOTHILL LOCATIONS...MAINLY BOULDER COUNTY FOOTHILLS SOUTHWARD
TO JEFFERSON/DOUGLAS COUNTIES. THE SOUTHERN FOOTHILLS HAVE NOT
BEEN DOING VERY WELL WITH REGARD TO SNOW AMOUNTS IN THE PAST
COUPLE STORMS BUT GIVEN THE STRONGER FLOW LATER TODAY WE DO EXPECT
HEAVIER TOTALS THERE. ANOTHER CONCERNING AREA IF CONVECTION
BLOSSOMS AS MESOSCALE MODELS INDICATE WOULD BE THE WESTERN SUBURBS
FOR POTENTIAL WARNING CRITERIA. HARD TO EXACTLY SAY HOW THIS COMES
TOGETHER BUT FOR NOW WILL ISSUE ADVISORIES STARTING AROUND 3 PM
FOR THE DENVER/BOULDER METRO AREA AND PALMER DIVIDE. FORT COLLINS
PER DISCUSSION ABOVE SEEMS TO GET EXCLUDED FROM HEAVIER
PRECIPITATION AGAIN. SOME THREAT WESTERN SUBURBS COULD GET A QUICK
6 INCHES PLUS LATE THIS AFTERNOON/EVENING SO WILL MONITOR FOR
POTENTIAL UPGRADE TO WARNING. OVERALL...THERE WILL BE A VERY LARGE
DISPARITY WITH SNOW TOTALS WITH LITERALLY TRACE TO 10 INCH AMOUNTS
POSSIBLE IN PORTIONS OF THE DENVER METRO AREA...AND HARD TO
PINPOINT WHO GETS EXACTLY HOW MUCH. ONCE SNOW DEVELOPS WE DO
ANTICIPATE RAPID DETERIORATION OF CONDITIONS AS SNOW INTENSITY
COULD TURN DRY AND WARM ROADS INTO A QUICK SHEET OF PACKED
SNOW/ICE. THE LATE AFTERNOON/EVENING COMMUTE FOR THE
DENVER/BOULDER/PALMER DIVIDE/FOOTHILLS AREAS LOOKS DIFFICULT AT
THIS POINT.
FOR OVERNIGHT...SNOW INTENSITY IS EXPECTED TO GRADUALLY DECREASE
WITH UPSLOPE COMPONENT WEAKENING AND AIRMASS STABILIZING WITH
COLDER/DRIER BOUNDARY LAYER FLOW. MOST OF THE ACCUMULATING SNOW
SHOULD BE OVER BY DAYBREAK SO WILL RUN WARNINGS AND ADVISORIES TIL
6 AM.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 424 AM MST WED FEB 25 2015
THE MEDIUM RANGE MODELS CONTINUE TO INDICATE THAT THIS EVENINGS
SNOWFALL IS THE BEGINNING OF A PROLONGED PERIOD OF LIGHT SNOW
ACROSS MUCH OF THE FORECAST AREA...ESPECIALLY THE MOUNTAINS. THE
FLOW PATTERN ALOFT IS FORECAST TO BEGIN AS A CYCLONICALLY CURVED
NORTHWESTERLY FLOW WITH A COUPLE EMBEDDED SHORT WAVE TROUGHS. BY
FRIDAY EVENING...FLOW ALOFT ACROSS COLORADO WILL BECOME MORE
WESTERLY AS AN UPPER TROUGH BEGINS CARVING OUT OVER THE PACIFIC
NORTHWEST AND THEN GREAT BASIN. THE WESTERLY FLOW WILL BE MOIST
WITH ENOUGH CYCLONIC CURVATURE TO MAINTAIN WEAK QUASI-GEOSTROPHIC
FORCING FOR ASCENT ACROSS THE STATE. THIS WILL RESULT IN A
CONTINUATION OF LIGHT SNOWFALL THROUGH FRIDAY AND SATURDAY. AT
LOWER LEVELS...A VERY COLD AIRMASS WILL MOVE INTO THE REGION
BEHIND THIS AFTERNOONS COLD FRONT AND TAKE UP RESIDENCE OVER
NORTHEAST COLORADO THROUGH ABOUT SUNDAY. A LARGE SURFACE HIGH
OVER THE CENTRAL PLAINS WILL MAINTAIN SOUTHEASTERLY LOW LEVEL FLOW
ACROSS EASTERN COLORADO WELL INTO THE WEEKEND. THIS SHOULD
CONTINUE FEEDING MOISTURE INTO THE REGION WHICH COULD BE HELD
AGAINST THE FOOTHILLS BY A DENVER CYCLONE THAT WILL DEVELOP
THURSDAY NIGHT AND LAST THROUGH SATURDAY. WITH WEAK DYNAMICS
REMAINING OVERHEAD AND MOIST AIR AT LOWER LEVELS...LIGHT SNOW WILL
BE POSSIBLE WHILE THE UPPER FLOW PATTERN REMAINS IN PLACE.
BY LATE IN THE WEEKEND...THE UPPER TROUGH WILL SINK TO THE DESERT
SOUTHWEST...LEAVING COLORADO UNDER THE DEFORMATION ZONE DOWNSTREAM
OF THE UPPER CIRCULATION. THIS WILL PRODUCE THE HEAVIEST SNOWFALL
MORE OVER SOUTHWESTERN COLORADO...SIMILAR TO WHAT OCCURRED THIS
PAST MONDAY. BUT THE NORTH-CENTRAL COLORADO MOUNTAINS WILL BE ON
THE NORTHERN FRINGES OF THIS SYSTEM AND SHOULD RECEIVE AT LEAST
LIGHT SNOWFALL. NO FORECAST PERIOD IS EXPECTED TO CONTAIN
PARTICULARLY HEAVY SNOWFALL AMOUNTS...BUT SEVERAL CONSECUTIVE
PERIODS WITH 2 TO 4 INCHES OF NEW SNOW COULD ADD UP AFTER AWHILE.
TEMPERATURE-WISE...THE COLDEST TEMPERATURES FOR NORTHEAST COLORADO
WILL BE THURSDAY AND FRIDAY WITH ONLY SLIGHT MODERATION THROUGH
THE WEEKEND. DURING THE FIRST HALF OF NEXT WEEK...THE GFS AND
ECMWF HAVE SLIGHTLY DIFFERENT SCENARIOS INVOLVING THE WESTERN U.S.
TROUGH MOVING ACROSS COLORADO. THIS WILL KEEP THE RATHER UNSETTLED
WEATHER OVER THE STATE THROUGH THAT TIME. LITTLE WARMING CAN BE
EXPECTED UNTIL AFTER THE MAIN TROUGH CLEARS THE AREA. ALL IN
ALL...SNOWPACK CONDITIONS WILL ONLY IMPROVE THROUGH THE NEXT WEEK.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 945 AM MST WED FEB 25 2015
STRONG NORTHEAST WINDS ASSOCIATED WITH THE COLD FRONT ALREADY AT
KDEN AND WILL BE AT KBJC AND KAPA. TIMING FOR THE ONSET OF PCPN
WILL LIKELY MOVE UP AS WELL.
VFR CONDITIONS THROUGH 18Z. WINDS NORTHEAST...WITH GUSTS AROUND
25 KNOTS EXPECTED. EXPECT ILS RESTRICTIONS BY 19Z WITH SOME MVFR
CIG/VSBY RESTRICTIONS IN THE DEVELOPING SNOW SHOWERS. IFR
CONDITIONS AND HEAVIER SNOW SHOWERS DEVELOPING 19Z-22Z WITH
POTENTIAL FOR 1-2 INCH PER HOUR SNOW RATES AND TEMPO 1/4SM
VISIBILITY 22Z-02Z. HIGHEST THREAT WOULD BE AT KBJC AND KAPA...BUT
SOME THREAT AT KDEN TOO. OVERALL INTENSITY SHOULD DECREASE AFTER
04Z BUT IFR CONDITIONS WILL LIKELY LINGER WITH LIGHT SNOW THROUGH
EARLY THURSDAY MORNING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM MST
THURSDAY FOR COZ039>041.
WINTER STORM WARNING FROM 2 PM THIS AFTERNOON TO 6 AM MST
THURSDAY FOR COZ035-036.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 6 AM MST
THURSDAY FOR COZ033-034.
&&
$$
UPDATE...COOPER
SHORT TERM...BARJENBRUCH
LONG TERM...DANKERS
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1213 PM CST WED FEB 25 2015
.UPDATE...
ISSUED AT 1159 AM CST WED FEB 25 2015
CONTINUE TO ASSESS THE EVOLUTION OF THE CLIPPER SYSTEM TO TRY AND
RESOLVE ANY CHANGES TO HEADLINES LATER THIS AFTERNOON. INITIAL
THOUGHTS THAT HEAVIER FORCING/H8-H7 MB BASED FRONTOGENETICAL BAND
WITH THE HEAVY SNOW RATES CURRENTLY ACRS NE IA INTO WEST CENTRAL
IA MAY EXPAND SOME AND DROP SOUTHEASTWARD ACRS THE WESTWARD THIRD
FROM MID AFTERNOON TO EARLY EVENING...AND EXPAND ACRS THE SOUTHERN
THIRD OF THE DVN CWA THIS EVENING THROUGH MIDNIGHT WITH GREATEST
RATE OF ACCUMULATIONS OCCURRING UNDER IT. THE 12Z 4KM WRF MAY BE ON
TO SOMETHING AND SHOWS SIMILAR HANDLING. SOME CONCERN IF THE
BAND PROGRESSES LIKE THE WRF SHOWS THAT SNOW AMOUNTS IN THE
NORTHWESTERN HALF OF THE WARNING AREA MAY BE TOO HIGH BY A FEW
INCHES...THE CURRENTLY ADVERTISED 6-9 INCHES MAY BE MORE LIKE 4-7
INCHES IN THOSE AREAS. NORTHEASTERN ADVISORY AREAS MORE LIKE 2-4
INCHES AS OPPOSED TO 3-6 INCHES. ONGOING AMOUNTS SOUTH OF I80
STILL LOOK ON TARGET FOR THE MOST PART WITH BULK OF ACCUMS DOWN
THERE OCCURRING AFTER 5 PM THIS EVENING. THERE MAY BE A NEED TO
EXPAND ADVISORY INTO BUREAU COUNTY IF THE WESTERN PART OF THAT
COUNTY WILL BE IN LINE FOR WIDESPREAD 3-4 INCHES. CHALLENGES
APLENTY FOR THE AFTERNOON. ..12..
&&
.SYNOPSIS...
ISSUED AT 330 AM CST WED FEB 25 2015
AT 330 AM...MID LEVEL CLOUDS WERE STREAMING INTO THE AREA AHEAD OF
A ROBUST CLIPPER SYSTEM. SNOW WAS CONTINUING TO DEVELOP ACROSS
PARTS OF SOUTH DAKOTA AND SOUTHWEST MINNESOTA. EARLY MORNING
TEMPERATURES WERE IN THE TEENS TO LOWER 20S AT MOST LOCATIONS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CST WED FEB 25 2015
THE MAIN FORECAST ISSUE IS THE IMPENDING POTENT CLIPPER SYSTEM AND
ASSOCIATED SNOWFALL AMOUNTS AND COVERAGE.
LOOKING AT THE VARIOUS SYNOPTIC AND HIGH RES MODELS...LATEST
TRENDS HAVE BEEN TOWARD HIGHER SNOWFALL AMOUNTS AND A SLIGHTLY
FARTHER NORTH AXIS OF THE HEAVIEST SNOW. THE INITIAL ISSUE IS
TIMING OF THE ONSET OF SNOW...DEPENDENT ON HOW THE DEFORMATION
ZONE/DRY SLOT SET UP. THE WRF IS A BIT FASTER IN BRINGING SNOW
INTO THE WEST THIS MORNING...WHILE THE RAP HAS A MORE PRONOUNCED
DRY SLOT EARLY IN THE EVENT. FOR PURPOSES OF THE FORECAST GRIDS
AND HEADLINES...HAVE GONE WITH THE EARLIER TIMING...WHICH CAN BE
ADJUSTED THROUGH THE DAY.
GIVEN THE STRENGTH AND DEPTH OF THE FORCING THROUGH THE DENDRITIC
LAYER...THE HIGHER SNOWFALL AMOUNTS LOOK REASONABLE BASED ON
AVERAGE SNOW RATIOS THROUGH THE BULK OF THE EVENT IN THE 14-19:1
RANGE. ALSO FAVORED CONSENSUS QPF...WHICH IS SLIGHTLY HIGHER TO
THE NORTH THAN WPC VALUES. THE END RESULT IS ROUGHLY 6-9 INCHES
FROM INDEPENDENCE...TO WAPELLO...FORT MADISON AND POINTS EAST.
HAVE UPGRADED THESE AREAS TO A WINTER STORM WARNING. FROM
DUBUQUE...THROUGH THE QUAD CITIES...WEST CENTRAL ILLINOIS...AND
FAR NORTHEAST MISSOURI...EXPECTING GENERAL 3-6 INCH AMOUNTS WITH A
WINTER WEATHER ADVISORY IN EFFECT. LOCALLY ENHANCED HIGHER SNOWFALL
AMOUNTS ARE NOT OUT OF THE QUESTION IN THE ADVISORY AREA.
ADJUSTMENTS TO SNOWFALL AMOUNTS/HEADLINES ARE INEVITABLE AS WE
HEAD THROUGH THE DAY AND INTO THIS EVENING.
PEAK SNOWFALL INTENSITY EXPECTED IN THE AFTERNOON/EVENING...WHICH
WILL MAKE FOR A HAZARDOUS COMMUTE WITH SNOW COVERED ROADS AND
REDUCED VISIBILITY. A NORTHWEST WIND AROUND 15 MPH WITH HIGHER
GUSTS WILL LIKELY PRODUCE SOME SHALLOW DRIFTING SNOW AT TIMES. THE
SNOW WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST LATE TONIGHT INTO
THURSDAY MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 330 AM CST WED FEB 25 2015
THURSDAY AND FRIDAY...VERY COLD PERIOD AS ARCTIC ~1042 MB HIGH
BUILDS INTO THE MIDWEST. FRESH POWDERY SNOW ON THE GROUND/LIGHT
WINDS (POSSIBLY DECOUPLED AT TIMES)/AND MAINLY CLEAR SKIES WILL SET
THE STAGE FOR VERY COLD OVERNIGHT LOWS. CURRENT FORECAST FAVORS THE
RAW GFS/ECMWF AS SUPERBLEND/NAM SEEM TO BE TOO WARM.
EXPECT WIDESPREAD LOWS BETWEEN -10 TO -15 F WHICH WOULD BE NEAR
RECORD TERRITORY FOR LATE FEBRUARY...SINGLE DIGIT SUB-ZERO LOWS ARE
MORE LIKELY SOUTH OF BURLINGTON. WINDS WILL REMAIN ON THE LIGHT SIDE
BUT EVEN AT 5-7 KTS THEY WILL BE ENOUGH TO CREATE DANGEROUS WIND
CHILLS BETWEEN -20 TO -30 F AT TIMES. VALUES NEAR -30 F SHOULD BE
RELATIVELY ISOLATED AND SHORT-LIVED. HIGHS ARE FORECAST TO BE IN THE
UPPER SINGLE DIGITS TO MID TEENS.
SATURDAY AND SUNDAY...SIGNIFICANT PATTERN CHANGE WILL OCCUR DURING
THIS TIME AS UPPER JET DIGS OUT A LARGE TROUGH OVER THE WESTERN U.S.
WHICH WILL CAUSE A BIG SHIFT IN THE ORIENTATION OF THE 850 MB
BAROCLINIC ZONE TO A SW-NE DIRECTION.
THERE HAS BEEN A CONSISTENT SIGNAL OF SIGNIFICANT LOW/MID LEVEL
MOISTURE ADVECTION FROM THE SW U.S. AND FROM THE GULF OF MEXICO FOR
SAT NIGHT INTO SUN. THEREFORE...A PERIOD OF SNOW IS LIKELY WITH
AMOUNTS UNCERTAIN THIS FAR OUT. WITH THE LACK OF A STRONG SHORTWAVE
TROUGH/VORTICITY MAX...MODELS DEVELOP LINEAR-LOOKING FRONTAL PRECIP
AND DO NOT DEVELOP A COHERENT SFC LOW WHICH WOULD PUT SOMEWHAT OF A
LIMIT ON THIS SYSTEM. DAYTIME TEMPS WILL BE IN THE 20S ON SAT AND
THE UPPER 20S TO LOWER 30S ON SUN.
MONDAY AND TUESDAY...CHANCE OF PRECIP MORE LIKELY LATER IN THE DAY
AND INTO TUE. MODELS STILL STRUGGLING WITH WHEN TO EJECT ORGANIZED
500 MB VORTICITY MAX OUT OF THE FOUR CORNERS AREA. THE GFS HAS A
WELL ORGANIZED SFC LOW TRACKING FROM OKLAHOMA TO NORTHERN INDIANA
WHICH IS FAVORABLE FOR WIDESPREAD PRECIP IN THE DVN CWA. WARMER AIR
ALOFT MAY MAKE IT FAR ENOUGH NORTH TO BRING VARYING PRECIP TYPES TO
PORTIONS OF THE FORECAST AREA. STAY TUNED. EARLY LOOK AT FORECAST
HIGHS ARE IN THE UPPER 20S TO MIDDLE 30S ON TUE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1147 AM CST WED FEB 25 2015
SNOW COMING IN AND SATURATING FOR LOW MVFR TO LIFR CONDITIONS AT
DBQ AND CID ALREADY...MLI BY 1-2 PM AND BRL MAINLY 2-3 PM. EAST
WINDS TO BACK TO THE NORTH TO NORTHEAST THIS EVENING INTO THU
MORNING. 10-20 KT WINDS COMBINING WITH FALLING SNOW COMPOUNDING
VSBYS THIS AFTERNOON THOUGH THE EVENING. CONDITIONS TO IMPROVE FROM
NORTH TO SOUTH AFTER MIDNIGHT TONIGHT THROUGH MID THU MORNING...
FIRST AT DBQ/CID WHICH MAY BE MVFR BY SUNRISE. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR CLINTON-
DELAWARE-DUBUQUE-JACKSON-JONES-SCOTT.
WINTER STORM WARNING UNTIL 6 AM CST THURSDAY FOR CEDAR-DES
MOINES-HENRY IA-JEFFERSON-LEE-LOUISA-MUSCATINE-VAN BUREN.
WINTER STORM WARNING UNTIL 3 AM CST THURSDAY FOR BENTON-BUCHANAN-
IOWA-JOHNSON-KEOKUK-LINN-WASHINGTON.
IL...WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR HENRY IL-
MERCER-ROCK ISLAND.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST
THURSDAY FOR HANCOCK-HENDERSON-MCDONOUGH-WARREN.
MO...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST
THURSDAY FOR CLARK-SCOTLAND.
&&
$$
UPDATE...12
SYNOPSIS...RP KINNEY
SHORT TERM...RP KINNEY
LONG TERM...UTTECH
AVIATION...12
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
205 PM EST WED FEB 25 2015
.UPDATE...
ISSUED AT 205 PM EST WED FEB 25 2015
DID A QUICK UPDATE TO FINE TUNE TEMPERATURES AND SKY COVER THROUGH
THE REST OF THE DAY WITH THE SNOW SLATED TO MOVE IN AROUND 00Z IN
OUR SOUTHERN COUNTIES...BUT QUICKLY SPREADING NORTH AND EAST INTO
THE EVENING HOURS...MAINLY JUST AFFECTING THE ADVISORY AREAS. THE
UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 1125 AM EST WED FEB 25 2015
15Z SFC ANALYSIS SHOWS A WEAK AREA OF HIGH PRESSURE RETREATING OFF
TO THE EAST AHEAD OF A PAIR OF APPROACHING LOW PRESSURE SYSTEMS.
THE MAIN ONE OF CONCERN WILL BE ONE COMING OUT OF THE NORTHERN
GULF WITH A WELL DEFINED COMMA HEAD OF PRECIPITATION. HIGH CLOUDS
AHEAD OF THIS LOW HAVE OVERSPREAD THE AREA LIKELY CAPPING OUR
TEMPERATURE CLIMB THIS AFTERNOON. READINGS ARE IN THE UPPER 20S
AND LOW 30S THROUGH EASTERN KENTUCKY WITH DEWPOINTS HOLDING IN THE
MID TEENS WHILE THE WINDS ARE LIGHT AND VARIABLE. THE FORECAST IS
ON TRACK FOR THE REST OF THE DAY AS THE SNOW APPROACHES FROM THE
SOUTH. THE LATEST HRRR HOLDS OFF ON ITS ARRIVAL INTO KENTUCKY
UNTIL AFTER 00Z STILL TARGETING THE FAR SOUTHEAST FOR ANY DECENT
ACCUMULATIONS. UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS...ALONG WITH A FRESHENED SET OF ZONES.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 421 AM EST WED FEB 25 2015
CURRENT CONDITIONS ACROSS THE AREA AS OF 09Z FEATURE JUST SOME LOW
LEVEL CLOUD COVER TRACKING OVER EASTERN KENTUCKY FROM THE
NORTHWEST AS A WEAK TROUGH IS MOVING THROUGH. THIS FEATURES WILL
LIKELY THROW A FEW FLURRIES ACROSS SOME LOCATIONS THIS MORNING
BEFORE HEADING OFF TO THE EAST. THE CLOUD COVER MOVING OVER THE
AREA HAS REALLY KEPT OUR LOW TEMPERATURES UP FOR MINS THIS
MORNING. AT THIS TIME...A DEVELOPING SYSTEM BEGINS TO TAKE SHAPE
OVER THE LOWER MS RIVER VALLEY AND WILL TRACK NORTHEAST TODAY.
SHORT TERM MODELS HAVE COME INTO DECENT AGREEMENT WITH THIS
FEATURE AS A STRONG SHORTWAVE WILL BE ASSOCIATED WITH SURFACE LOW
PRESSURE DEVELOPING AND MOVING EAST INTO THE LOWER TN VALLEYS AND
APPALACHIANS BY 00Z TONIGHT.
THE PREVIOUS RUNS HAVE TRENDED THIS FEATURE NORTH FAR ENOUGH TO
BRING A DECENT SHOT OF ACCUMULATING SNOWFALL TO SOUTHERN AND
SOUTHEASTERN EAST KENTUCKY. MODEL PROFILES DO SHOW A DECENT DRY
AIR LAYER TO OVERCOME BUT AS EXPERIENCED IN THE PREVIOUS EVENT IN
THE SOUTHERN STREAM...THE LAYER CAN BE OVERCOME QUITE EFFECTIVELY
WITH THE AMOUNT OF GULF MOISTURE THIS SYSTEM WILL BE TAPPING INTO.
AS WELL THE SOUTHERN AND EASTERN COUNTIES THROUGH THIS EVENT WILL
HAVE A SATURATED LAYER IN THE -10 TO -20 CELSIUS ZONE FOR A GOOD
PORTION OF THIS EVENT. THE CLOUD COVER HANGING AROUND EARLIER IN
THE DAY THAT KEPT TEMPS WARM MAY HAVE AN EFFECT ON AMOUNTS FROM
THE EVENT TONIGHT BUT DIURNAL TRENDS AND NORTHEAST LOW LEVEL FLOW
SHOULD BE COLD ENOUGH FOR SNOW AT ONSET. THEREFORE...WITH THESE
FACTORS...HAVE GONE WITH 10 OR 12 TO 1 SNOW RATIOS IN THE SOUTH
AND THEN GOING HIGHER IN THE NORTHWEST TOWARDS THE COLDER AIR.
THIS WILL GIVE SNOW AMOUNTS IN THE 1 TO 2 INCH RANGE WITH UP TO 3
INCHES IN THE HIGHER ELEVATIONS. WENT WITH AN WINTER WEATHER
ADVISORY FOR THIS AND WILL PUT AN SPS OUT FOR THE NORTHERN
COUNTIES AS SOME OF THOSE AREAS MAY AT LEAST GET UP TO AN
INCH...ESPECIALLY WITH THE HIGHER RATIOS.
HEADING INTO THE DAY ON THURSDAY...THE SYSTEM MOVES OFF TO THE
EAST AS ANOTHER ARCTIC FRONT MOVES IN BEHIND THE SYSTEM. THIS
PATTERN WILL ONCE AGAIN FAVOR AN UPSLOPE EVENT FOR SNOW SHOWERS
BUT NOT ANTICIPATING SIGNIFICANT ACCUMULATIONS FROM THIS AS
PROFILES SEEM TO BE TOO DRY BUT ALSO LACKING IN ANY SIGNIFICANT
INSTABILITY. KEPT AMOUNTS FOR THIS THROUGH THE DAY UNDER AN INCH
WITH HIGH RATIOS.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 427 AM EST WED FEB 25 2015
THE SOUTHERN STREAM SHORTWAVE AND ASSOCIATED SURFACE LOW WILL BE
WELL NE TO START THE PERIOD. THE NORTHERN STREAM DISTURBANCE WILL
KEEP CHANCE POPS ESPECIALLY ACROSS THE FAR SE OVERNIGHT BEFORE
EXIT THE REGION MOVING INTO FRIDAY. UPPER LEVELS WILL GRADUALLY
TRANSITION TO ZONAL FLOW. SURFACE HIGH PRESSURE ACROSS THE PLAINS
WILL THEN GRADUALLY BUILD EAST ACROSS THE OHIO AND TENNESSEE
VALLEYS. THIS WILL ONCE AGAIN USHER IN WELL BELOW NORMAL TEMPS
ACROSS THE REGION WITH LOWS DROPPING INTO THE SINGLE DIGITS AND
TEENS THUR AND FRI NIGHT AND HIGHS FRI IN THE 20S. THIS HIGH
PRESSURE WILL BE FAIRLY TRANSIENT WITH A BIT OF RETURN FLOW AS WE
MOVE INTO SATURDAY UNDER PARTLY CLOUDY SKIES WITH INCREASING
CLOUDS TOWARD EVENING. HIGHS ON SATURDAY BOUNCE BACK INTO THE LOW
TO MID 30 NORTH AND AND MID TO UPPER 30S SOUTH. THIS HIGH PRESSURE
WILL CONTINUE MOVING EAST ACROSS THE MID ATLANTIC OVERNIGHT
SATURDAY. THEN EYES WILL TURN TO OVERRUNNING EVENT FOR THE FIRST
PART OF NEXT WEEK. INITIALLY THIS WILL BRING INCREASE IN CLOUDS ON
SATURDAY NIGHT INTO SUNDAY. INCREASE IN POPS WILL ALSO BEGIN
PARTICULARLY SUNDAY AFTERNOON. THERE ARE REMAINS A FAIR AMOUNT OF
UNCERTAINTIES AROUND EXACT AMTS AND TRACK OF THIS OVERRUNNING
PORTION OF THE SYSTEM. THEN LATE IN THE PERIOD FOCUS SHIFTS TO THE
UPPER LEVEL TROUGH ACROSS THE SW US STRENGTHENING AND EJECTING NE.
THIS WILL BRING SURFACE LOW ACROSS THE MIDWEST INTO THE OHIO
VALLEY BY TUESDAY OR WEDNESDAY. THE GFS AND ECMWF MODELS DISAGREE
ON TIMING OF THIS SURFACE LOW WITH GFS MOST PROGRESSIVE AND RIGHT
NOW BLEND BRINGS BEST POPS FOR TUESDAY. EITHER WAY GIVEN
SUBSTANTIAL FETCH OF MOISTURE WITH PWATS AT OR ABOVE 1 INCH AND
EVEN A CONVECTIVE ELEMENT WITH THE FRONT/NEGATIVELY TILTED
TROUGH...THIS WILL POSE A FLOODING THREAT ESPECIALLY IN AREAS THAT
STILL HAVE A SUBSTANTIAL SNOW PACK. FUTURE SHIFTS WILL HAVE TO
CONTINUE TO MONITOR THE POTENTIAL FOR FLOODING ISSUES AND FLOODING
PRODUCTS WILL POSSIBLY NEED TO BE ISSUED FOR THIS WARMUP AND
PRECIP EVENT AS WE MOVE INTO THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 130 PM EST WED FEB 25 2015
EXPECT VFR CONDITIONS TO CONTINUE THROUGH THE FIRST PART OF THE
TAF PERIOD. LOOK FOR HIGH CIGS TO DROP TO AROUND 4K FEET BY 02Z IN
THE SOUTH AND BY 04Z NORTH WITH SOME IFR OR LOWER CIGS AND VIS
ANTICIPATED TOWARD MIDNIGHT ACROSS THE SOUTHERN TIER OF THE
FORECAST AREA. THESE LOWER CIGS WILL ACCOMPANY THE NORTHERN FRINGE
OF A SIGNIFICANT WINTER STORM SYSTEM PASSING THROUGH THE
SOUTHEAST PARTS OF THE NATION BRINGING A PERIOD OF SNOW TO THE
AREA. THE HEAVIEST AND HARDEST OF THE SNOW WILL FALL SOUTHEAST OF
OF MAIN TAF SITES. THE SNOW WILL TAPER OFF AND CIGS WILL START TO
IMPROVE INTO THE DAY ON THURSDAY. WINDS WILL BE LIGHT AND VARIABLE
THROUGH LATE EVENING FOR MOST PLACES BEFORE SWITCHING TO THE
NORTHEAST AND NORTH AT BETWEEN 5 AND 10 KTS THROUGH THE DAY
THURSDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST
THURSDAY FOR KYZ079-080-083>088-110-113-115>118-120.
&&
$$
UPDATE...GREIF
SHORT TERM...SHALLENBERGER
LONG TERM...DJ
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1125 AM EST WED FEB 25 2015
.UPDATE...
ISSUED AT 1125 AM EST WED FEB 25 2015
15Z SFC ANALYSIS SHOWS A WEAK AREA OF HIGH PRESSURE RETREATING OFF
TO THE EAST AHEAD OF A PAIR OF APPROACHING LOW PRESSURE SYSTEMS.
THE MAIN ONE OF CONCERN WILL BE ONE COMING OUT OF THE NORTHERN
GULF WITH A WELL DEFINED COMMA HEAD OF PRECIPITATION. HIGH CLOUDS
AHEAD OF THIS LOW HAVE OVERSPREAD THE AREA LIKELY CAPPING OUR
TEMPERATURE CLIMB THIS AFTERNOON. READINGS ARE IN THE UPPER 20S
AND LOW 30S THROUGH EASTERN KENTUCKY WITH DEWPOINTS HOLDING IN THE
MID TEENS WHILE THE WINDS ARE LIGHT AND VARIABLE. THE FORECAST IS
ON TRACK FOR THE REST OF THE DAY AS THE SNOW APPROACHES FROM THE
SOUTH. THE LATEST HRRR HOLDS OFF ON ITS ARRIVAL INTO KENTUCKY
UNTIL AFTER 00Z STILL TARGETING THE FAR SOUTHEAST FOR ANY DECENT
ACCUMULATIONS. UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS...ALONG WITH A FRESHENED SET OF ZONES.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 421 AM EST WED FEB 25 2015
CURRENT CONDITIONS ACROSS THE AREA AS OF 09Z FEATURE JUST SOME LOW
LEVEL CLOUD COVER TRACKING OVER EASTERN KENTUCKY FROM THE
NORTHWEST AS A WEAK TROUGH IS MOVING THROUGH. THIS FEATURES WILL
LIKELY THROW A FEW FLURRIES ACROSS SOME LOCATIONS THIS MORNING
BEFORE HEADING OFF TO THE EAST. THE CLOUD COVER MOVING OVER THE
AREA HAS REALLY KEPT OUR LOW TEMPERATURES UP FOR MINS THIS
MORNING. AT THIS TIME...A DEVELOPING SYSTEM BEGINS TO TAKE SHAPE
OVER THE LOWER MS RIVER VALLEY AND WILL TRACK NORTHEAST TODAY.
SHORT TERM MODELS HAVE COME INTO DECENT AGREEMENT WITH THIS
FEATURE AS A STRONG SHORTWAVE WILL BE ASSOCIATED WITH SURFACE LOW
PRESSURE DEVELOPING AND MOVING EAST INTO THE LOWER TN VALLEYS AND
APPALACHIANS BY 00Z TONIGHT.
THE PREVIOUS RUNS HAVE TRENDED THIS FEATURE NORTH FAR ENOUGH TO
BRING A DECENT SHOT OF ACCUMULATING SNOWFALL TO SOUTHERN AND
SOUTHEASTERN EAST KENTUCKY. MODEL PROFILES DO SHOW A DECENT DRY
AIR LAYER TO OVERCOME BUT AS EXPERIENCED IN THE PREVIOUS EVENT IN
THE SOUTHERN STREAM...THE LAYER CAN BE OVERCOME QUITE EFFECTIVELY
WITH THE AMOUNT OF GULF MOISTURE THIS SYSTEM WILL BE TAPPING INTO.
AS WELL THE SOUTHERN AND EASTERN COUNTIES THROUGH THIS EVENT WILL
HAVE A SATURATED LAYER IN THE -10 TO -20 CELSIUS ZONE FOR A GOOD
PORTION OF THIS EVENT. THE CLOUD COVER HANGING AROUND EARLIER IN
THE DAY THAT KEPT TEMPS WARM MAY HAVE AN EFFECT ON AMOUNTS FROM
THE EVENT TONIGHT BUT DIURNAL TRENDS AND NORTHEAST LOW LEVEL FLOW
SHOULD BE COLD ENOUGH FOR SNOW AT ONSET. THEREFORE...WITH THESE
FACTORS...HAVE GONE WITH 10 OR 12 TO 1 SNOW RATIOS IN THE SOUTH
AND THEN GOING HIGHER IN THE NORTHWEST TOWARDS THE COLDER AIR.
THIS WILL GIVE SNOW AMOUNTS IN THE 1 TO 2 INCH RANGE WITH UP TO 3
INCHES IN THE HIGHER ELEVATIONS. WENT WITH AN WINTER WEATHER
ADVISORY FOR THIS AND WILL PUT AN SPS OUT FOR THE NORTHERN
COUNTIES AS SOME OF THOSE AREAS MAY AT LEAST GET UP TO AN
INCH...ESPECIALLY WITH THE HIGHER RATIOS.
HEADING INTO THE DAY ON THURSDAY...THE SYSTEM MOVES OFF TO THE
EAST AS ANOTHER ARCTIC FRONT MOVES IN BEHIND THE SYSTEM. THIS
PATTERN WILL ONCE AGAIN FAVOR AN UPSLOPE EVENT FOR SNOW SHOWERS
BUT NOT ANTICIPATING SIGNIFICANT ACCUMULATIONS FROM THIS AS
PROFILES SEEM TO BE TOO DRY BUT ALSO LACKING IN ANY SIGNIFICANT
INSTABILITY. KEPT AMOUNTS FOR THIS THROUGH THE DAY UNDER AN INCH
WITH HIGH RATIOS.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 427 AM EST WED FEB 25 2015
THE SOUTHERN STREAM SHORTWAVE AND ASSOCIATED SURFACE LOW WILL BE
WELL NE TO START THE PERIOD. THE NORTHERN STREAM DISTURBANCE WILL
KEEP CHANCE POPS ESPECIALLY ACROSS THE FAR SE OVERNIGHT BEFORE
EXIT THE REGION MOVING INTO FRIDAY. UPPER LEVELS WILL GRADUALLY
TRANSITION TO ZONAL FLOW. SURFACE HIGH PRESSURE ACROSS THE PLAINS
WILL THEN GRADUALLY BUILD EAST ACROSS THE OHIO AND TENNESSEE
VALLEYS. THIS WILL ONCE AGAIN USHER IN WELL BELOW NORMAL TEMPS
ACROSS THE REGION WITH LOWS DROPPING INTO THE SINGLE DIGITS AND
TEENS THUR AND FRI NIGHT AND HIGHS FRI IN THE 20S. THIS HIGH
PRESSURE WILL BE FAIRLY TRANSIENT WITH A BIT OF RETURN FLOW AS WE
MOVE INTO SATURDAY UNDER PARTLY CLOUDY SKIES WITH INCREASING
CLOUDS TOWARD EVENING. HIGHS ON SATURDAY BOUNCE BACK INTO THE LOW
TO MID 30 NORTH AND AND MID TO UPPER 30S SOUTH. THIS HIGH PRESSURE
WILL CONTINUE MOVING EAST ACROSS THE MID ATLANTIC OVERNIGHT
SATURDAY. THEN EYES WILL TURN TO OVERRUNNING EVENT FOR THE FIRST
PART OF NEXT WEEK. INITIALLY THIS WILL BRING INCREASE IN CLOUDS ON
SATURDAY NIGHT INTO SUNDAY. INCREASE IN POPS WILL ALSO BEGIN
PARTICULARLY SUNDAY AFTERNOON. THERE ARE REMAINS A FAIR AMOUNT OF
UNCERTAINTIES AROUND EXACT AMTS AND TRACK OF THIS OVERRUNNING
PORTION OF THE SYSTEM. THEN LATE IN THE PERIOD FOCUS SHIFTS TO THE
UPPER LEVEL TROUGH ACROSS THE SW US STRENGTHENING AND EJECTING NE.
THIS WILL BRING SURFACE LOW ACROSS THE MIDWEST INTO THE OHIO
VALLEY BY TUESDAY OR WEDNESDAY. THE GFS AND ECMWF MODELS DISAGREE
ON TIMING OF THIS SURFACE LOW WITH GFS MOST PROGRESSIVE AND RIGHT
NOW BLEND BRINGS BEST POPS FOR TUESDAY. EITHER WAY GIVEN
SUBSTANTIAL FETCH OF MOISTURE WITH PWATS AT OR ABOVE 1 INCH AND
EVEN A CONVECTIVE ELEMENT WITH THE FRONT/NEGATIVELY TILTED
TROUGH...THIS WILL POSE A FLOODING THREAT ESPECIALLY IN AREAS THAT
STILL HAVE A SUBSTANTIAL SNOW PACK. FUTURE SHIFTS WILL HAVE TO
CONTINUE TO MONITOR THE POTENTIAL FOR FLOODING ISSUES AND FLOODING
PRODUCTS WILL POSSIBLY NEED TO BE ISSUED FOR THIS WARMUP AND
PRECIP EVENT AS WE MOVE INTO THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 644 AM EST WED FEB 25 2015
EXPECT VFR CONDITIONS THROUGH MUCH OF THE TAF PERIOD. THERE IS A
WEAK FRONT MOVING THROUGH THE AREA THIS MORNING AND THERE MAY BE
A FEW LOCATIONS AFTER DAWN WHERE A 3 KFT CIG POPS UP BUT
OVERALL...CIGS WILL BE AROUND 4 KFT. THROUGH THE DAY...WINDS WILL
BE LIGHT AND VARIABLE WITH CLOUD COVER INCREASING TOWARDS THE END
OF THE TAF PERIOD. SOME IFR CEILINGS WILL MOVE IN AFTER 00Z INTO
THE LOZ...SME...AND JKL...THEN LOCATIONS NORTH...AS THE NEXT
SYSTEM MOVES IN. SOME LIGHT SNOW WILL DEVELOP INTO THESE AREAS
AFTER 03Z TONIGHT. BY 06Z TONIGHT AND TILL THE END OF THE
PERIOD...BELOW FIELD MINS IN VIS AND CIGS WILL SET IN AS THE MORE
MODERATE SNOW MOVES IN.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST
THURSDAY FOR KYZ079-080-083>088-110-113-115>118-120.
&&
$$
UPDATE...GREIF
SHORT TERM...SHALLENBERGER
LONG TERM...DJ
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1220 PM EST WED FEB 25 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 AM EST WED FEB 25 2015
AN ARCTIC AIRMASS WILL REMAIN FIRMLY ENTRENCHED IN THE GREAT LAKES
REGION THROUGH FRIDAY. A WEAK SYSTEM WILL BRING A FEW LIGHT SNOW
SHOWERS TO FAR SOUTHERN LOWER MICHIGAN TONIGHT INTO THURSDAY
MORNING. HIGH PRESSURE WILL BUILD IN TO PRODUCE FAIR BUT COLD
WEATHER THURSDAY THROUGH SATURDAY. TEMPERATURES WILL FINALLY
UNDERGO A GRADUAL MODERATING TREND LATE THIS WEEKEND INTO EARLY
NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1110 AM EST WED FEB 25 2015
THIS IS JUST A QUICK HEADS UP ON MY THINKING FOR TONIGHT. I AM
THINKING IT WILL SNOW TONIGHT (HIGH POP) NEAR AND SOUTH OF I-96.
THIS WILL NOT BE A HEAVY SNOW... MOSTLY AN INCH OR LESS BUT IT
WILL SNOW NONE THE LESS.
AFTER LOOKING AT THE NAM12...RAP13 AND HRRR IT SEEMS TO ME WHAT
WE WILL SEE IS A NARROW BAND OF SNOW DEVELOPING NEAR OR JUST NORTH
OF I-96 AROUND 9 TO 10 PM TONIGHT THAT WILL MOVE SLOWLY SOUTHWARD
(THIS IS SHOWN BY ALL THREE OF THESE MODELS) TO I-94 BY 5 AM. THIS
NARROW BAND IS THE RESULT OF SURFACE FGEN DUE THE RADIATIONAL COOLED
AIR OVER NORTHERN LOWER MICHIGAN COMPARED TO THE CLOUD COVERED AIR
(WHICH WILL NOT COOL) CREATING A THERMAL GRADIENT. THE BEST LIFT
IS JUST ABOVE THE IS NEAR 900 MB WHICH IS IN THE DGZ SO THIS WILL
MAXIMIZE THE SNOWFALL RATES. THIS IS GOING ON UNDER THE ENTRANCE
REGION OF THE UPPER JET SO WE GET DEEP MOISTURE AND DEEP LIFT
(WEAK BUT ALSO IN THE DGZ). AROUND MIDNIGHT THE DGZ OVER GRR IS
FROM 1000 FT TO 12000 FT....MORE THAN DEEP ENOUGH TO HELP THE SNOW
CAUSE. BOTTOM LINE IS I WILL INCREASE THE POP TO OVER 70% OVER THE
SOUTHERN 1/2 OF THE CWA THIS EVENING FOR THIS EVENT.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EST WED FEB 25 2015
FAIRLY TRANQUIL AND COLD WEATHER IS ANTICIPATED THROUGH THE SHORT
TERM FCST PERIOD. A FEW LIGHT SNOW SHOWERS AND FLURRIES WILL
LINGER INTO THIS MORNING BUT WITH VERY LITTLE TO NO ADDITIONAL
SNOW ACCUMULATION. MOST OF THE DAY WILL BE DRY BUT COLD WITH A MIX
OF SUN AND CLOUDS. MAX TEMPS WILL ONLY REACH 10 TO 15 DEGREES.
A WEAK SYSTEM MOVING ESE FROM THE NORTHERN PLAINS STATES EARLY
THIS MORNING WILL BRING A FEW LIGHT SNOW SHOWERS AND FLURRIES TO
OUR SOUTHERN FCST AREA NEAR TO MAINLY SOUTH OF I-96 TONIGHT INTO
THURSDAY MORNING... WITH VERY LIGHT SNOW ACCUMULATIONS OF UNDER AN
INCH.
BEYOND THAT HIGH PRESSURE WILL BUILD IN TO PRODUCE FAIR BUT COLD
WX THURSDAY AFTERNOON THROUGH FRIDAY. MAX TEMPS THURSDAY WILL
STRUGGLE TO REACH THE UPPER SINGLE DIGITS TO LOWER TEENS AND MINS
THURSDAY NIGHT WILL FALL TO BELOW ZERO ACROSS OUR AREA AS SKIES
CLEAR AND WITH LIGHT WINDS AND EXPANSIVE SNOW COVER IN PLACE. MAX
TEMPS FRIDAY WILL STRUGGLE TO REACH THE LOWER TO MIDDLE TEENS IN
SPITE OF LOTS OF SUN AFTER A VERY COLD START TO THE DAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EST WED FEB 25 2015
UPPER AIR PATTERN SHIFT IS STILL FORECAST TO OCCUR BY THE 00Z MODEL
RUNS DURING THE LONG TERM. THE PERSISTENT UPPER TROUGH IS IN THE
PROCESS OF LIFTING OUT FRIDAY NIGHT. BY EARLY NEXT WEEK A SOUTHWEST
FLOW DEVELOPS ACROSS THE LOWER 48...FROM THE SOUTHWEST U.S. TO THE
GREAT LAKES.
THERE ARE TWO MAIN ITEMS TO KEEP AN EYE ON THROUGH THE PERIOD. THE
FIRST IS THE SNOW EVENT FOR SUNDAY AND SUNDAY NIGHT. IT REMAINS AN
EVENT WITH NO SURFACE LOW TO KEY ON. SNOW IS PRODUCED VIA A WEAK
FRONTAL BOUNDARY SLIPPING THROUGH THE AREA COUPLED WITH AN UPPER
LEVEL SHORT WAVE AND ISENTROPIC LIFT. IT APPEARS TO BE A 2-5 INCH
SNOW POTENTIALLY FOR THE SOUTHERN HALF OF THE FORECAST AREA. WE
STILL HAVE PLENTY OF TIME TO NAIL DOWN THE DETAILS WITH THIS SYSTEM.
THE SECOND SIGNIFICANT FEATURE TO KEEP AN EYE ON IS A SYSTEM NEXT
WEEK IN THE TUESDAY OR WEDNESDAY TIME FRAME. LOW CONFIDENCE IN THIS
TIME FRAME AS THE GFS IS QUICKER...BRINGING A DEEP LOW THROUGH THE
AREA ON TUESDAY. THE ECMWF AND CANADIAN ARE SLOWER AND BRING THE
SYSTEM THROUGH ON WEDNESDAY. AT THIS POINT...SIDING WITH THE ECMWF
AND CANADIAN AND THE SLOWER SYSTEM. THE SYSTEM TAPS GULF MOISTURE IN
DEEP SOUTHERLY FLOW. PRECIPITATION TYPE ISSUES COME INTO PLAY
TUESDAY NIGHT IN THE ECMWF/CANADIAN SOLUTIONS WITH +4 TO +6 850MB
AIR SURGING IN FROM THE SOUTH. THESE VALUES WOULD YIELD RAIN AS THE
PRECIP TYPE ALONG I94. MODELS ARE HAVING ISSUES WITH THIS SYSTEM AS
ITS DRIVEN BY A WAVE EJECTING OUT OF THE SOUTHWEST U.S. TROUGH. WE
WILL BE MONITORING TRENDS WITH THIS SYSTEM IN THE COMING DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1219 PM EST WED FEB 25 2015
OUR MAIN CONCERN WITH THE 18Z FCSTS IS DEALING WITH THE SNOW
COMING IN FROM LATE THIS AFTERNOON THROUGH THU MORNING. MID CLOUDS
ARE NOW STARTING TO STREAM IN OVER THE AREA...WITH SOME
DIURNAL/LAKE EFFECT CLOUD COVER NOW STARTING TO DEVELOP/MOVE
INLAND. WE EXPECT THAT ONLY KMKG WILL SEE THE LOWEST CONDITIONS
THIS AFTERNOON WITH 3500 FT CIGS AND SOME FLURRIES.
LIGHT SNOW WILL THEN BREAK OUT ACROSS THE TERMINALS THIS EVENING
INTO THE EARLY OVERNIGHT HOURS. MODELS ARE INDICATING THAT A LOCAL
BAND MAY SET UP AND POTENTIALLY IMPACT THE KGRR AREA FOR A SHORT
TIME THIS EVENING WITH SOME LOWER VSBYS. MVFR IS LIKELY WITH SOME
LOCAL IFR POSSIBLE.
A LIGHT SNOW WILL THEN LIKELY PERSIST OVERNIGHT AND INTO THU
MORNING. THIS WILL LAST LONGER ACROSS THE SOUTH. THE LOWER
CONDITIONS WILL ALSO BE ACROSS THE SOUTH CLOSER TO THE SYSTEM.
AGAIN...MVFR IS LIKELY WITH SOME IFR POSSIBLE AT TIMES. THIS WILL
GRADUALLY MOVE OUT THU MORNING. CONDITIONS WILL IMPROVE GRADUALLY
THU AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 224 PM EST TUE FEB 24 2015
CURRENTLY NO SUSPECTED ICE JAMS AND RIVER LEVELS ARE HOLDING RATHER
STEADY. FORECAST CALLS FOR BELOW FREEZING TEMPERATURES INTO NEXT
WEEK WITH OCCASIONAL SNOW OPPORTUNITIES. THE RISK OF FLOODING IS
FAIRLY LIMITED UNTIL A NOTABLE WARM-UP OR RAIN EVENT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...DUKE
AVIATION...NJJ
HYDROLOGY...CAS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1110 AM EST WED FEB 25 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 330 AM EST WED FEB 25 2015
AN ARCTIC AIRMASS WILL REMAIN FIRMLY ENTRENCHED IN THE GREAT LAKES
REGION THROUGH FRIDAY. A WEAK SYSTEM WILL BRING A FEW LIGHT SNOW
SHOWERS TO FAR SOUTHERN LOWER MICHIGAN TONIGHT INTO THURSDAY
MORNING. HIGH PRESSURE WILL BUILD IN TO PRODUCE FAIR BUT COLD
WEATHER THURSDAY THROUGH SATURDAY. TEMPERATURES WILL FINALLY
UNDERGO A GRADUAL MODERATING TREND LATE THIS WEEKEND INTO EARLY
NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1110 AM EST WED FEB 25 2015
THIS IS JUST A QUICK HEADS UP ON MY THINKING FOR TONIGHT. I AM
THINKING IT WILL SNOW TONIGHT (HIGH POP) NEAR AND SOUTH OF I-96.
THIS WILL NOT BE A HEAVY SNOW... MOSTLY AN INCH OR LESS BUT IT
WILL SNOW NONE THE LESS.
AFTER LOOKING AT THE NAM12...RAP13 AND HRRR IT SEEMS TO ME WHAT
WE WILL SEE IS A NARROW BAND OF SNOW DEVELOPING NEAR OR JUST NORTH
OF I-96 AROUND 9 TO 10 PM TONIGHT THAT WILL MOVE SLOWLY SOUTHWARD
(THIS IS SHOWN BY ALL THREE OF THESE MODELS) TO I-94 BY 5 AM. THIS
NARROW BAND IS THE RESULT OF SURFACE FGEN DUE THE RADIATIONAL COOLED
AIR OVER NORTHERN LOWER MICHIGAN COMPARED TO THE CLOUD COVERED AIR
(WHICH WILL NOT COOL) CREATING A THERMAL GRADIENT. THE BEST LIFT
IS JUST ABOVE THE IS NEAR 900 MB WHICH IS IN THE DGZ SO THIS WILL
MAXIMIZE THE SNOWFALL RATES. THIS IS GOING ON UNDER THE ENTRANCE
REGION OF THE UPPER JET SO WE GET DEEP MOISTURE AND DEEP LIFT
(WEAK BUT ALSO IN THE DGZ). AROUND MIDNIGHT THE DGZ OVER GRR IS
FROM 1000 FT TO 12000 FT....MORE THAN DEEP ENOUGH TO HELP THE SNOW
CAUSE. BOTTOM LINE IS I WILL INCREASE THE POP TO OVER 70% OVER THE
SOUTHERN 1/2 OF THE CWA THIS EVENING FOR THIS EVENT.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EST WED FEB 25 2015
FAIRLY TRANQUIL AND COLD WEATHER IS ANTICIPATED THROUGH THE SHORT
TERM FCST PERIOD. A FEW LIGHT SNOW SHOWERS AND FLURRIES WILL
LINGER INTO THIS MORNING BUT WITH VERY LITTLE TO NO ADDITIONAL
SNOW ACCUMULATION. MOST OF THE DAY WILL BE DRY BUT COLD WITH A MIX
OF SUN AND CLOUDS. MAX TEMPS WILL ONLY REACH 10 TO 15 DEGREES.
A WEAK SYSTEM MOVING ESE FROM THE NORTHERN PLAINS STATES EARLY
THIS MORNING WILL BRING A FEW LIGHT SNOW SHOWERS AND FLURRIES TO
OUR SOUTHERN FCST AREA NEAR TO MAINLY SOUTH OF I-96 TONIGHT INTO
THURSDAY MORNING... WITH VERY LIGHT SNOW ACCUMULATIONS OF UNDER AN
INCH.
BEYOND THAT HIGH PRESSURE WILL BUILD IN TO PRODUCE FAIR BUT COLD
WX THURSDAY AFTERNOON THROUGH FRIDAY. MAX TEMPS THURSDAY WILL
STRUGGLE TO REACH THE UPPER SINGLE DIGITS TO LOWER TEENS AND MINS
THURSDAY NIGHT WILL FALL TO BELOW ZERO ACROSS OUR AREA AS SKIES
CLEAR AND WITH LIGHT WINDS AND EXPANSIVE SNOW COVER IN PLACE. MAX
TEMPS FRIDAY WILL STRUGGLE TO REACH THE LOWER TO MIDDLE TEENS IN
SPITE OF LOTS OF SUN AFTER A VERY COLD START TO THE DAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EST WED FEB 25 2015
UPPER AIR PATTERN SHIFT IS STILL FORECAST TO OCCUR BY THE 00Z MODEL
RUNS DURING THE LONG TERM. THE PERSISTENT UPPER TROUGH IS IN THE
PROCESS OF LIFTING OUT FRIDAY NIGHT. BY EARLY NEXT WEEK A SOUTHWEST
FLOW DEVELOPS ACROSS THE LOWER 48...FROM THE SOUTHWEST U.S. TO THE
GREAT LAKES.
THERE ARE TWO MAIN ITEMS TO KEEP AN EYE ON THROUGH THE PERIOD. THE
FIRST IS THE SNOW EVENT FOR SUNDAY AND SUNDAY NIGHT. IT REMAINS AN
EVENT WITH NO SURFACE LOW TO KEY ON. SNOW IS PRODUCED VIA A WEAK
FRONTAL BOUNDARY SLIPPING THROUGH THE AREA COUPLED WITH AN UPPER
LEVEL SHORT WAVE AND ISENTROPIC LIFT. IT APPEARS TO BE A 2-5 INCH
SNOW POTENTIALLY FOR THE SOUTHERN HALF OF THE FORECAST AREA. WE
STILL HAVE PLENTY OF TIME TO NAIL DOWN THE DETAILS WITH THIS SYSTEM.
THE SECOND SIGNIFICANT FEATURE TO KEEP AN EYE ON IS A SYSTEM NEXT
WEEK IN THE TUESDAY OR WEDNESDAY TIME FRAME. LOW CONFIDENCE IN THIS
TIME FRAME AS THE GFS IS QUICKER...BRINGING A DEEP LOW THROUGH THE
AREA ON TUESDAY. THE ECMWF AND CANADIAN ARE SLOWER AND BRING THE
SYSTEM THROUGH ON WEDNESDAY. AT THIS POINT...SIDING WITH THE ECWMF
AND CANADIAN AND THE SLOWER SYSTEM. THE SYSTEM TAPS GULF MOISTURE IN
DEEP SOUTHERLY FLOW. PRECIPITATION TYPE ISSUES COME INTO PLAY
TUESDAY NIGHT IN THE ECMWF/CANADIAN SOLUTIONS WITH +4 TO +6 850MB
AIR SURGING IN FROM THE SOUTH. THESE VALUES WOULD YIELD RAIN AS THE
PRECIP TYPE ALONG I94. MODELS ARE HAVING ISSUES WITH THIS SYSTEM AS
ITS DRIVEN BY A WAVE EJECTING OUT OF THE SOUTHWEST U.S. TROUGH. WE
WILL BE MONITORING TRENDS WITH THIS SYSTEM IN THE COMING DAYS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 710 AM EST WED FEB 25 2015
SCATTERED TO BROKEN CLOUDS ARE IN PLACE ACROSS SOUTHWEST LOWER
MICHIGAN AT 12Z. THE BULK OF THE CLOUDS WERE LOCATED TOWARDS LAKE
MICHIGAN IN A NORTHWEST FLOW. EXPECTING SCATTERED TO BROKEN CLOUDS
TO CONTINUE THROUGH THE DAY...WITH CEILINGS VARYING BETWEEN VFR
AND MVFR.
TONIGHT...SOME LIGHT SNOW WILL SPREAD IN FROM THE WEST...WITH MVFR
CEILINGS BECOMING MORE PREVALENT...ESPECIALLY TOWARDS THE I-94 TAF
SITES FROM KAZO TO KJXN.
WINDS THROUGH THE PERIOD WILL BE FAIRLY LIGHT SHIFTING FROM THE
NORTHWEST TO THE NORTHEAST THE NEXT 24 HOURS.
&&
.HYDROLOGY...
ISSUED AT 224 PM EST TUE FEB 24 2015
CURRENTLY NO SUSPECTED ICE JAMS AND RIVER LEVELS ARE HOLDING RATHER
STEADY. FORECAST CALLS FOR BELOW FREEZING TEMPERATURES INTO NEXT
WEEK WITH OCCASIONAL SNOW OPPORTUNITIES. THE RISK OF FLOODING IS
FAIRLY LIMITED UNTIL A NOTABLE WARM-UP OR RAIN EVENT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...CAS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1135 AM CST WED FEB 25 2015
.DISCUSSION...MESSY AND COMPLEX WEATHER SITUATION ACROSS THE REGION
THIS MORNING WITH A WIDE RANGE OF PRECIP TYPES ACROSS THE CWA. OVER
THE NORTH AND WEST OF THE AREA...TEMPERATURES HAVE BEEN HOVERING
NEAR FREEZING THROUGHOUT THE MORNING...WITH PREDOMINATELY SLEET AND
LIGHT FREEZING RAIN. AS FAR SOUTH AS HINDS...MADISON...NEWTON AND
LAUDERDALE COUNTIES...WE HAVE BEEN RECEIVING REPORTS OF NEW ICE
ACCUMULATIONS ON TREES AND POWERLINES AND EVEN NEW POWER OUTAGES
RESULTING FROM LARGE LIMBS BREAKING. GENERALLY SOUTH OF I-20 (EXCEPT
FOR IN NE LOUISIANA)...PRECIP IS ALL LIQUID. IN THE DELTA...WE ARE
NOW BEGINNING TO SEE A TRANSITION TO SLEET THEN SNOW. THE SWITCH TO
SNOW HAS JUST TAKEN PLACE IN OUR SOUTHEAST AR COUNTIES AND WILL BE
OCCURRING ACROSS THE RIVER INTO THE CLEVELAND AND GREENVILLE AREAS
SHORTLY. JUST WEST OF THE CWA...THE TRANSITION TO MODERATE AND AT
TIMES HEAVY SNOW HAS BEEN FAST...AND SNOWFALL RATES HAVE BEEN HIGH
AT TIMES WITH ACCUMULATIONS OF 2-3 INCHES TAKING PLACE OVER PARTS OF
SOUTH AR AND NORTH LA WITHIN JUST THE PAST FEW HOURS.
THROUGH THE MORNING...THE HRRR HAS HANDLED THE SLOWER TRANSITION TO
ALL SNOW WELL AS THE MID LEVEL VORT SWINGS INTO THE AREA MORE IN THE
AFTERNOON. DESPITE THE LATER TRANSITION...IT STILL INDICATES HEAVIER
SNOW ALONG THE HIGHWAY 82 CORRIDOR AS DYNAMIC COOLING OCCURS IN THE
COLD CORE. THIS SCENARIO WAS COVERED PRETTY WELL IN THE PREVIOUS
DISCUSSION...AND OUR FORECAST THINKING HAS CHANGED LITTLE THUS
FAR...EXCEPT TO PUSH BACK THE START OF HEAVIER SNOW A FEW HOURS. WE
ALSO STILL CANNOT RULE OUT THUNDER IN CONVECTIVE BANDS...AND REPORTS
OF THIS HAVE BEEN RECEIVED BACK TO OUR WEST ALREADY THIS MORNING.
FOR THE UPDATE IT WAS NECESSARY TO CHANGE THE PROPORTION OF ICE/SNOW
ACCUMS DURING THE EARLY DAY TIME FRAME BASED ON THE GREATER
PREVALENCE OF FREEZING RAIN. HOWEVER...HEAVIEST SNOW ACCUMS ARE
STILL IN THE LATER PORTION OF THE DAY AND NO MAJOR ADJUSTMENTS WERE
MADE TO THESE. STILL EXPECTING THE HIGHEST ACCUMULATIONS ALONG AND
NORTH OF THE HIGHWAY 82 CORRIDOR. OTHER ELEMENTS OF THE FORECAST
WERE GENERALLY ON TRACK AND NO MAJOR ADJUSTMENTS WILL BE MADE AT
THIS TIME. /DL/
&&
.AVIATION...PLENTY OF AVIATION ISSUES TODAY. VSBY RESTRICTED BY RAIN
AND SOON TO BE BY SNOW. HAVE CARRIED VSBY REDUCTIONS TO 1/2SM AT
KGLH...KGWO AND KGTR THIS AFTERNOON FOR SEVERAL HOURS. WILL WATCH
FOR FURTHER RESTRICTIONS SPECIFICALLY AT KJAN AND KHKS THIS
AFTERNOON.
CEILINGS ARE IFR AT SEVERAL SITES AND A FURTHER LOWERING IS EXPECTED
THIS AFTERNOON...AND WILL CONTINUE IN THE IFR CATEGORY AFTER THE
STORM PASSES THIS EVENING AND OVERNIGHT. FORTUNATELY...THIS STORM
HAS NO WINDS TO SPEAK OF. /SW/
&&
.PREV DISCUSSION... /ISSUED AT 458 AM CST WED FEB 25 2015/
SHORT TERM...THROUGH THURSDAY NIGHT...AS RAPIDLY AS THE SYSTEM CAME
IN IT WILL EXIT BY LATE THIS AFTERNOON/EVENING. THE HEAVIER PRECIP
WILL TAPER OFF TO LIGHT WITH THE I20 CORRIDOR SEEING THE MIX CHANGE
OVER TO LIGHT SNOW/FLURRIES BEFORE ENDING. CLOUD COVER LOOKS TO EXIT
PRETTY CLOSE ON THE HEELS OF THE PRECIP AS WELL. WITH CLEAR
SKIES...CALM WINDS AND INCREASED ALBEDO FROM THE SNOW COVER...EXPECT
TEMPS TO DROP LIKE A ROCK OVERNIGHT WITH LOW TO MID 20S OVER THE
NORTH AND NEAR 30 OVER THE FAR SOUTH./26/
LONG TERM...FRIDAY THROUGH WEDNESDAY...COOL HIGH PRESSURE FROM A
HIGH CENTERED OVER THE OHIO VALLEY WILL PREVAIL ACROSS THE REGION ON
FRIDAY. TEMPERATURES WILL CONTINUE TO BE COLD WITH LOWS IN THE 20S
AND HIGHS ONLY CLIMBING INTO THE 40S TO AROUND 50 IN THE SOUTH.
AS THE SURFACE HIGH SHIFTS TO THE EAST COAST ON SATURDAY THE SURFACE
FLOW WILL BECOME MORE EASTERLY AND EVENTUALLY SOUTHEASTERLY BY
SUNDAY. TEMPERATURES WILL BE ON THE RISE ON SATURDAY WITH WARMER
HIGHS IN THE UPPER 40S TO UPPER 50S IN THE SOUTH. AS THE FLOW
BECOMES SOUTHERLY SATURDAY NIGHT INTO SUNDAY MOISTURE WILL INCREASE
ACROSS THE AREA. THE GFS/ECMWF ARE IN GOOD AGREEMENT THAT A WARM
FRONT WILL PUSH NORTHWARD ALONG WITH INCREASING INSTABILITY SUNDAY
AFTERNOON AND THIS WILL KICK OF SOME THUNDERSTORM ACTIVITY. THIS IS
SEVERAL DAYS OUT...BUT CURRENTLY IT LOOKS LIKE THERE IS SOME
POTENTIAL FOR ELEVATED STRONG STORMS SUNDAY AFTERNOON WITH HAIL
BEING THE MAIN CONCERN.
ON MONDAY THE GFS AND ECMWF ARE GENERALLY IN DECENT AGREEMENT OF
SOUTHWEST FLOW ALOFT AND WEAK UPPER RIDGING ...BUT DIFFER ON THE
PLACEMENT OF THE FRONTAL BOUNDARY WITH THE GFS FURTHER SOUTH OVER THE
AREA WHILE THE ECMWF IS WELL TO THE NORTH. WILL LEAN TOWARDS THE
ECMWF WHICH WILL ALLOW MUCH WARMER TEMPERATURES OVER THE AREA ON
MONDAY. FROM MONDAY BOTH THE GFS/ECMWF MOVE A SERIES OF SHORT WAVES
ACROSS THE PLANES INTO THE OHIO VALLEY THROUGH THE REMAINDER OF THE
PERIOD. THE MODELS DIFFER ON THE TIMING OF THESE SYSTEMS...BUT BOTH
OF THE MODELS KEEP THE UPPER HEIGHTS FAIRLY HIGH WITH MOST OF THE
ENERGY REMAINING TO THE NORTH. CIPS ANALOGS INDICATE THAT THERE IS AN
INCREASED RISK FOR SEVERE THUNDERSTORMS BY MIDWEEK AND BOTH THE GFS
AND ECMWF HAVE A MORE POTENT SYSTEM DURING THIS PERIOD ALSO. WITH
THIS OVERALL PATTERN EXPECT THERE WILL BE A GOOD CHANCE FOR SEVERE
THUNDERSTORMS NEXT WEEK AS THERE WILL BE PLENTY OF MOISTURE AND
INSTABILITY TO WORK WITH./15/
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR MSZ018-019-
025>042.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
MSZ043>053.
LA...WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR LAZ007>009-
015.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR LAZ016-
023>025.
AR...WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR ARZ074-075.
&&
$$
DL/SW/26/15/
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1125 AM CST Wed Feb 25 2015
.UPDATE...
Issued at 1005 AM CST WED FEB 25 2015
This morning`s model runs, including the short-term HRRR and RAP,
continue to trend a bit further east with the surface low track which
now looks to track from near Maryville to just west of Chillicothe to
near Boonville. Didn`t make any significant changes to snow amounts
to the east of the low track, still generally 2" to 4" across the
advisory area, but it now looks like anything more than 4" will be
just outside our CWA across southeast IA. With the surface low
tracking over Maryville, any advisory-level snows should fall just
east of Nodaway County so this county was removed from the winter
weather advisory.
To the west of the low track, any precipitation will be limited to a
short-window just behind a cold front which will track through later
this evening. This front will bring a rapid drop in temperatures so
that any precipitation that starts as rain should quickly be able to
switch to snow. Decent post-frontal convergence and shallow low-
level frontogenesis may still be able to squeeze out a quick sprinkle
or snow shower despite the recent runs of the RAP and HRRR keeping
these areas completely dry. However the odds of any snow accumulation
reaching an inch or more are low. Updated the forecast for the KC
metro and points south and west to keep snow amounts generally under
a half inch. The bigger concern for these areas will be potential
flash-freezing of any rain or melting snow that does fall, with
temperatures forecast to be dropping into the 20s across all areas by
midnight.
&&
.SHORT TERM...(Today through Friday)
Issued at 412 AM CST WED FEB 25 2015
Water vapor showing well anticipated shortwave trough dropping through
the northern Rockies this morning...with associated sfc reflection
now analyzed along the central Nebraska/South Dakota border. Out
ahead of the sfc low...latest sfc obs show a stationary boundary
extending east-southeast through southern Iowa into northern Illinois
and Indiana. With time today...main shortwave and sfc low will
continue tracking along this boundary before passing over the lower
Missouri Valley later tonight. As has been advertised in recent
days...region remains in the cross-hairs for accumulating snowfall
later tonight as system passes overhead. One would think that the
fcst would have been fairly easy this morning with us being so close
to event start time...but that could not be further from the truth as
latest 00z guidance has come in with a more northward track of the
main sfc low later tonight. With this being the case...our region stands
an excellent chance of warming quite a bit higher than previously
thought...which adds a fair amount of complexity to the going
forecast. Out ahead of the low...southwest downslope winds will
combine with modest warm air advection to allow temperatures to reach
the lower to middle 50s across west-central Missouri and eastern
Kansas to include the KC and STJ metros. To the east...a lingering
snowpack remains in place along and north of the Missouri River which
will likely result in a fairly impressive thermal gradient later this
afternoon. Meanwhile areas north of Route 36 also stand a decent
chance of warming up today as much of far northern Missouri also remains
snow free. In any event...warmer temps and the overall delay of the
system/s arrival by a few hours has resulted in changes to the fcst
to include snow total amounts.
As a result of the delayed arrival...latest models show precip
struggling to work into the area by 21z. With warmer temps in
place...precip will likely start out as rain across much of the
area...before cold air finally begins working into the region later
in the evening behind the main cold front. With limited winter precip
expected this afternoon...have elected to delay the winter weather
advisory start time until 21z this afternoon...and that may still be
a bit to early. In any event...models show main QPF max sliding
southeast over the area mainly between 00 and 06z tonight...with
precip gradually coming to an end from west to east during the early
morning hrs. Considering the amount of warming during the day...warm
ground temps should limit overall accumulations early on...before
precip rates increase heading into the early overnight hrs. In terms
of accumulations...expect maybe an inch in the greater KC area...with
even less across our eastern Kansas and our west-central Missouri
zones south of I-70. Further east where the heavier precip is
expected...have trimmed back on snowfall amounts slightly as fast
storm movement and delayed precip arrival time will likely lead to
slightly lower amounts. In general across the advisory area...expect
2-4" across most locations...however 3-5" will be possible north of
Kirksville before all is said and done. Cannot rule out a 6" report
up there but did not have enough confidence to even consider a
possible warning upgrade. As alluded to above...best accumulations
likely to occur after 00z...hence supporting the decision to slide
the advisory start time to the right.
Another factor to consider overnight will be the strong winds
with cold air advection following fropa. Current BUFKIT momentum
transfer tool output suggesting gusts in the mid to upper 30 kt range
later tonight. Combine this with any falling snow....blowing and
drifting will certainly be a possibility overnight.
Lingering light snow shwrs to come to an end by mid morning Thursday
as drier air and strong high pressure builds into the area. For the
remainder of the short term...focus will be on well below normal
temperatures as strong high pressure combines with fresh snow and clear
skies aloft. Have generally undercut guidance for temps both Thu and
Fri with Fri morning shaping up to be one of the coldest mornings of
the year /subzero at KCI?/. Any precip with this weekend/s system to
hold off until later on Saturday.
.LONG TERM...(Saturday through Tuesday)
Issued at 412 AM CST WED FEB 25 2015
Models continue to advertise an active weather pattern for much of
the extended range forecast. Two main features of interest that will
be the driving forces for sensible weather across our area will be:
1) An upper level trough across the central Rockies 2) A surface
front that will sink south through the forecast area and stall south
of the area.
On Saturday, an upper level trough will be sinking slow south across
the central Rockies. Further east, across the eastern half of the
CONUS, the upper flow will become quasi-zonal. Several shortwave
impulses will eject out from the upper level trough and into the
local area. Cold air will already be in place on Saturday and
precipitation should begin as snow...spreading from west to east
through the afternoon. Snow will continue through Saturday night.
Sunday, a cold front will sink south through the area reinforcing
the cold air and continue snow chances. However, as we get into
Sunday night we begin to lose ice crystals in the snow growth
zone...especially across the southern CWA...and snow may mix with or
change over to sleet.
Model solutions begin to diverge in the Monday to Tuesday timeframe.
On Monday, model differences revolve around how quickly the cold
front begins to lift back north towards the forecast area. Although,
precipitation continues to look likely on Monday, P-Type is more in
question with the front lifting back northward. Model soundings
indicate the potential for freezing rain to the south a wintry mix
across the central CWA with the northern CWA remaining snow. Tuesday
the main concern will be the upper level trough across the Rockies.
The GFS is faster moving it through the area on Tuesday bringing
another round of snow to the forecast area. The EC is about 24 hours
slower in moving the trough eastward into the local area. This
solution would bring a lull in precipitation on Tuesday with another
round of precipitation back in on Wednesday. Have maintained a
blended solution through this timeframe until forecast details can
be fine tuned.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1125 AM CST WED FEB 25 2015
Strong cold front will drop through the region early this evening with
an area of rain/snow spreading into northern Missouri behind it. Most
accumulating snow will stay well to the northeast of the KC area,
mainly affecting CDJ and IRK areas, possibly down to DMO. For the STJ
and KC areas, a few rain/snow showers are possible for a few hours
behind the front but any snow accumulations will be under a half inch
with minimal impacts to air operations, although a rapid drop in
temperatures could freeze any water on runways. The bigger concern
will be the winds which may occasionally gust higher than 35 kt.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...WINTER WEATHER ADVISORY from 3 PM this afternoon to 6 AM CST
Thursday FOR MOZ003>008-014>017-023>025-032-033.
&&
$$
UPDATE...Hawblitzel
SHORT TERM...32
LONG TERM...73
AVIATION...Hawblitzel
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1005 AM CST Wed Feb 25 2015
.UPDATE...
Issued at 1005 AM CST WED FEB 25 2015
This morning`s model runs, including the short-term HRRR and RAP,
continue to trend a bit further east with the surface low track which
now looks to track from near Maryville to just west of Chillicothe to
near Boonville. Didn`t make any significant changes to snow amounts
to the east of the low track, still generally 2" to 4" across the
advisory area, but it now looks like anything more than 4" will be
just outside our CWA across southeast IA. With the surface low
tracking over Maryville, any advisory-level snows should fall just
east of Nodaway County so this county was removed from the winter
weather advisory.
To the west of the low track, any precipitation will be limited to a
short-window just behind a cold front which will track through later
this evening. This front will bring a rapid drop in temperatures so
that any precipitation that starts as rain should quickly be able to
switch to snow. Decent post-frontal convergence and shallow low-
level frontogenesis may still be able to squeeze out a quick sprinkle
or snow shower despite the recent runs of the RAP and HRRR keeping
these areas completely dry. However the odds of any snow accumulation
reaching an inch or more are low. Updated the forecast for the KC
metro and points south and west to keep snow amounts generally under
a half inch. The bigger concern for these areas will be potential
flash-freezing of any rain or melting snow that does fall, with
temperatures forecast to be dropping into the 20s across all areas by
midnight.
&&
.SHORT TERM...(Today through Friday)
Issued at 412 AM CST WED FEB 25 2015
Water vapor showing well anticipated shortwave trough dropping through
the northern Rockies this morning...with associated sfc reflection
now analyzed along the central Nebraska/South Dakota border. Out
ahead of the sfc low...latest sfc obs show a stationary boundary
extending east-southeast through southern Iowa into northern Illinois
and Indiana. With time today...main shortwave and sfc low will
continue tracking along this boundary before passing over the lower
Missouri Valley later tonight. As has been advertised in recent
days...region remains in the cross-hairs for accumulating snowfall
later tonight as system passes overhead. One would think that the
fcst would have been fairly easy this morning with us being so close
to event start time...but that could not be further from the truth as
latest 00z guidance has come in with a more northward track of the
main sfc low later tonight. With this being the case...our region stands
an excellent chance of warming quite a bit higher than previously
thought...which adds a fair amount of complexity to the going
forecast. Out ahead of the low...southwest downslope winds will
combine with modest warm air advection to allow temperatures to reach
the lower to middle 50s across west-central Missouri and eastern
Kansas to include the KC and STJ metros. To the east...a lingering
snowpack remains in place along and north of the Missouri River which
will likely result in a fairly impressive thermal gradient later this
afternoon. Meanwhile areas north of Route 36 also stand a decent
chance of warming up today as much of far northern Missouri also remains
snow free. In any event...warmer temps and the overall delay of the
system/s arrival by a few hours has resulted in changes to the fcst
to include snow total amounts.
As a result of the delayed arrival...latest models show precip
struggling to work into the area by 21z. With warmer temps in
place...precip will likely start out as rain across much of the
area...before cold air finally begins working into the region later
in the evening behind the main cold front. With limited winter precip
expected this afternoon...have elected to delay the winter weather
advisory start time until 21z this afternoon...and that may still be
a bit to early. In any event...models show main QPF max sliding
southeast over the area mainly between 00 and 06z tonight...with
precip gradually coming to an end from west to east during the early
morning hrs. Considering the amount of warming during the day...warm
ground temps should limit overall accumulations early on...before
precip rates increase heading into the early overnight hrs. In terms
of accumulations...expect maybe an inch in the greater KC area...with
even less across our eastern Kansas and our west-central Missouri
zones south of I-70. Further east where the heavier precip is
expected...have trimmed back on snowfall amounts slightly as fast
storm movement and delayed precip arrival time will likely lead to
slightly lower amounts. In general across the advisory area...expect
2-4" across most locations...however 3-5" will be possible north of
Kirksville before all is said and done. Cannot rule out a 6" report
up there but did not have enough confidence to even consider a
possible warning upgrade. As alluded to above...best accumulations
likely to occur after 00z...hence supporting the decision to slide
the advisory start time to the right.
Another factor to consider overnight will be the strong winds
with cold air advection following fropa. Current BUFKIT momentum
transfer tool output suggesting gusts in the mid to upper 30 kt range
later tonight. Combine this with any falling snow....blowing and
drifting will certainly be a possibility overnight.
Lingering light snow shwrs to come to an end by mid morning Thursday
as drier air and strong high pressure builds into the area. For the
remainder of the short term...focus will be on well below normal
temperatures as strong high pressure combines with fresh snow and clear
skies aloft. Have generally undercut guidance for temps both Thu and
Fri with Fri morning shaping up to be one of the coldest mornings of
the year /subzero at KCI?/. Any precip with this weekend/s system to
hold off until later on Saturday.
.LONG TERM...(Saturday through Tuesday)
Issued at 412 AM CST WED FEB 25 2015
Models continue to advertise an active weather pattern for much of
the extended range forecast. Two main features of interest that will
be the driving forces for sensible weather across our area will be:
1) An upper level trough across the central Rockies 2) A surface
front that will sink south through the forecast area and stall south
of the area.
On Saturday, an upper level trough will be sinking slow south across
the central Rockies. Further east, across the eastern half of the
CONUS, the upper flow will become quasi-zonal. Several shortwave
impulses will eject out from the upper level trough and into the
local area. Cold air will already be in place on Saturday and
precipitation should begin as snow...spreading from west to east
through the afternoon. Snow will continue through Saturday night.
Sunday, a cold front will sink south through the area reinforcing
the cold air and continue snow chances. However, as we get into
Sunday night we begin to lose ice crystals in the snow growth
zone...especially across the southern CWA...and snow may mix with or
change over to sleet.
Model solutions begin to diverge in the Monday to Tuesday timeframe.
On Monday, model differences revolve around how quickly the cold
front begins to lift back north towards the forecast area. Although,
precipitation continues to look likely on Monday, P-Type is more in
question with the front lifting back northward. Model soundings
indicate the potential for freezing rain to the south a wintry mix
across the central CWA with the northern CWA remaining snow. Tuesday
the main concern will be the upper level trough across the Rockies.
The GFS is faster moving it through the area on Tuesday bringing
another round of snow to the forecast area. The EC is about 24 hours
slower in moving the trough eastward into the local area. This
solution would bring a lull in precipitation on Tuesday with another
round of precipitation back in on Wednesday. Have maintained a
blended solution through this timeframe until forecast details can
be fine tuned.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday Morning)
Issued at 520 AM CST WED FEB 25 2015
VFR conditions to continue much of the day with southwest winds
between 10-15 kts. By early evening...conditions will quickly
deteriorate to MVFR and eventually IFR and long anticipated storm
system moves overhead. Precip initially in the form of a RA/SN mix
will gradually change over to all SN as colder air filters into the
area. Terminals standing the best chance of seeing IFR VSBYs will be
STJ and MCI...with lower probabilities at remaining sites further south.
Precip will come to an end by 4z with low-end MVFR cigs remaining in
place through the duration of the fcst period. After fropa...winds
will quickly increase from the north by mid/late evening with north
winds gusting up to 35 kts overnight.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...WINTER WEATHER ADVISORY from 3 PM this afternoon to 6 AM CST
Thursday FOR MOZ003>008-014>017-023>025-032-033.
&&
$$
UPDATE...Hawblitzel
SHORT TERM...32
LONG TERM...73
AVIATION...32
AREA FORECAST DISCUSSION
NWS HASTINGS NE
353 PM CST WED FEB 25 2015
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 345 PM CST WED FEB 25 2015
LATEST RADAR SHOWS THE RAIN AND SNOW IS MOVING OUT OF THE FORECAST
AREA THIS AFTERNOON. THERE HAVE BEEN A FEW FLURRIES BEHIND THE MAIN
BAND...BUT EVEN THOSE ARE DIMINISHING THIS AFTERNOON. SURFACE
ANALYSIS HAS THE COLD FRONT ALREADY THROUGH THE FORECAST AREA AND
GUSTY NORTH WINDS ACROSS THE AREA. TEMPERATURES HAVE BEEN FALLING
FOR MUCH OF THE AREA THIS AFTERNOON.
MAIN QUESTION THIS AFTERNOON IS HOW QUICKLY THE PRECIPITATION WILL
MOVE OUT OF THE FORECAST AREA. THE RAP AND THE WRF BOTH INDICATE THE
PRECIPITATION SHOULD BE AN AFTERNOON EVENT AND BE DONE BEFORE THIS
EVENING. EVEN THE NAM AND THE GFS HAS IT ENDING BEFORE 00Z. WILL
START THE EVENING WITH A DRY FORECAST.
A SURFACE HIGH PRESSURE BUILDS IN THE DAKOTAS TONIGHT AND THURSDAY.
THIS WILL PUSH THE MOISTURE AND CLOUDS OUT OF THE AREA. SINCE THE
CENTER OF THE HIGH REMAINS TO THE NORTHEAST THROUGH THE
PERIOD...THERE WILL BE A FEW CLOUDS AROUND...BUT EXPECT CLOUDS TO
DIMINISH GRADUALLY LATE TONIGHT INTO THURSDAY.
THE COLD AIR HAS ALREADY STARTED TO MOVE INTO THE AREA THIS
AFTERNOON AND TEMPERATURES FOR MUCH OF THE AREA ARE COOLER NOW THAN
EARLIER. THE TEMPERATURES WILL CONTINUE TO PLUMMET TONIGHT WITH THE
DIMINISHING CLOUDS. THE COLD AIR REMAINS FIRMLY IN PLACE FOR
THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 345 PM CST WED FEB 25 2015
THE FOCUS OF THE LONG TERM FORECAST CENTERS AROUND PRECIPITATION
CHANCES OVER THE WEEKEND AND BEGINNING OF THE WORK WEEK AS WELL AS
BELOW NORMAL TEMPERATURES.
HEADING INTO THE LONG TERM...A DEEP UPPER LEVEL TROUGH WILL DIG
SOUTH ACROSS THE WESTERN COAST PROVIDING OUR WINTER WEATHER FOR THE
NEXT SEVERAL DAYS. THIS TROUGH WILL ALLOW MULTIPLE DISTURBANCES TO
TREK ACROSS THE CENTRAL PLAINS...WITH THE FIRST PASSING THROUGH
DURING THE WEEKEND TIMEFRAME AND THE SECOND HITTING MONDAY INTO
TUESDAY.
BY SATURDAY MORNING THE MAIN UPPER LEVEL LOW WILL BE POSITIONED
ALONG THE CALIFORNIA NEVADA BORDER WITH THE MID LEVEL LOW SLIGHTLY
EAST. THE FIRST ROUND OF MID LEVEL WAVES WILL BEGIN TO SLIDE THROUGH
THE PLAINS BY SATURDAY MORNING AHEAD OF THE PARENT LOW SYSTEM. IN
ADDITION TO THE WAVE...WARM AIR ADVECTION ACROSS THE PLAINS WILL
FUEL PLENTY OF MID LEVEL MOISTURE ACROSS THE REGION. WHILE THE GFS
IS STRONGER THAN THE ECMWF...BOTH MODEL SOLUTIONS SUGGEST GOOD
ISENTROPIC LIFT ESPECIALLY ACROSS KANSAS THROUGH THE WEEKEND.
FINALLY...A COLD FRONT WILL SLIDE THROUGH THE AREA SUNDAY MORNING
WITH AT LEAST SOME FRONTOGENETIC LIFT ALONG ITS BOUNDARY. ALTHOUGH
THIS IS NOT A MAJOR SYNOPTIC SETUP...BUT RATHER A MINOR
WAVE...SEVERAL KEY COMPONENTS ARE COMING TOGETHER TO FORM A DECENT
CHANCE FOR SNOW SATURDAY INTO SUNDAY MORNING. WITH MODEL AGREEMENT
LEANING TOWARDS BETTER LIFT OVER KANSAS...PLACED HIGHER AMOUNTS OVER
NORTH CENTRAL KANSAS. CURRENT MODEL TRENDS INDICATE THE POTENTIAL
FOR AT LEAST A COUPLE OF INCHES OF SNOW BY THE END OF THE WEEKEND
ACROSS NORTH CENTRAL KANSAS...POSSIBLY ADVISORY CRITERIA...WITH
LESSER AMOUNTS FARTHER NORTH.
THE NEXT SYSTEM SLIDES THROUGH MONDAY INTO TUESDAY...AND IS SOMEWHAT
MORE INTRIGUING. WHILE THE MAIN UPPER LEVEL LOW SLOWLY SHIFTS ACROSS
THE ROCKY MOUNTAINS...THE MID LEVEL LOW SURGES NORTHWARD ACROSS
NORTHERN NEBRASKA AND DAKOTAS. STRONG WARM AIR ADVECTION AND
SOUTHEASTERLY WINDS WILL BRING PLENTY OF MOISTURE AGAIN TO THE
CENTRAL PLAINS. ISENTROPIC LIFT IS BETTER IN BOTH THE GFS AND ECMWF
THAN THE WEEKEND STORM. AND ANOTHER COLD FRONT WILL DRAG ACROSS THE
CWA BY TUESDAY AFTERNOON. LOOKING AT ANOTHER ROUND OF SNOW FOR THE
FORECAST AREA. AT THIS TIME...ITS TOO EARLY TO DETERMINE
AMOUNTS...BUT RIGHT NOW MODELS FOCUS HEAVIER BANDS NORTH OF
INTERSTATE 80.
COLD TEMPERATURES CONTINUE THROUGHOUT THE LONG TERM...WITH AT LEAST
TWO SHOTS OF REINFORCING COLD AIR...AND LITTLE TO ANY WARM UPS. BOTH
COLD FRONTS...SUNDAY AND TUESDAY BRING VERY COLD 850 MB AIR TO THE
REGION...THE COLDER OF THE TWO ON TUESDAY. 850 TEMPERATURES DIP TO
NEAR 15 DEGREES BELOW BY WEDNESDAY AFTER THE COLD FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1123 AM CST WED FEB 25 2015
THE FIRST BAND OF PRECIPITATION HAS MOVED THROUGH THE TERMINALS
BUT THERE IS A LITTLE BIT BEHIND THE MAIN BAND. TEMPERATURES HAVE
BEEN FALLING AND SO THERE MAY BE A LITTLE SPRINKLE OR FLURRIES FOR
A TIME THIS AFTERNOON. HAVE LEFT IT OUT OF KEAR...BUT THERE COULD
BE A STRAY FLURRY EARLY THIS AFTERNOON. THE WINDIEST PERIOD WILL
BE THIS AFTERNOON...BUT BREEZY CONDITIONS ARE EXPECTED THROUGH THE
PERIOD. LOW CLOUDS WILL MOVE OUT OF THE AREA OVERNIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...JCB
LONG TERM...SALTZMAN
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1133 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST WED FEB 25 2015
...ARCTIC AIR RETURNS WITH A VENGEANCE WITH FRONTAL PASSAGE
ACCOMPANIED BY POSSIBLE RAIN/SNOW SHWRS FOLLOWED BY HOWLING N
WINDS UP TO 50 MPH...
ALOFT: SEVERAL WEAK/SUBTLE SHORTWAVE TROFS WILL CROSS THE FCST
AREA THRU TONIGHT IN NW FLOW. THE LEAD TROF WILL BE THE POTENTIAL
WX- MAKER WHICH WILL MOVE THRU 15Z-00Z...ASSOCIATED WITH THE
PASSAGE OF THE SFC LOW.
SURFACE: AN ARCTIC COLD FRONT EXTENDED FROM HUDSON BAY THRU THE
GREAT LAKES ACROSS IA TO LOW PRES OVER SD AND THEN NW INTO CANADA.
THIS LOW WILL HEAD SE ACROSS NEB TODAY AND IN ITS WAKE THE FRONT
WILL SURGE S TODAY AND WILL BE S OF THE FCST AREA BY SUNSET.
ARCTIC HIGH PRES THEN BEGINS BUILDING IN TONIGHT FROM CANADA.
EARLY THIS MORNING: CLOUDS WILL CONT TO INCREASE FROM THE NW.
GENERALLY MILD WITH TEMPS AT OR ABOVE FRZG MOST LOCATIONS.
HAZARDS: N WINDS WILL GUST 45-50 MPH 12PM-12AM. DANGEROUS WIND
CHILLS DOWN TO -20F LATE TONIGHT...N OF I-80.
TODAY: NOT SURE HOW IT UNFOLDS. WE KNOW FOR SURE THAT THE
STEADIEST PRECIP WILL BE E OF THE FCST AREA...ON THE COLD SIDE OF
THE FRONT IN THE WAA. SPOTTY ECHOES HAVE BEEN INCREASE THRU THE
NIGHT SW OF THE LOW THRU THE BLACK HILLS INTO THE PANHANDLE.
UPSTREAM SOUNDINGS SHOW A LOT OF DRY AIR IN THE LOW-LVLS. SO FAR
HAVE ONLY SEEN ONE STATION REPORT SPRINKLES UPSTREAM.
OVERALL EXPECT A M/CLOUDY DAY OVER S-CNTRL NEB AND BECOMING
M/CLOUDY OVER N-CNTRL KS. MOST MESOSCALE MODELS SUGGEST A
NARROW/BROKEN BAND OF STRONGLY-FORCED SHWRS WILL DEVELOP ALONG THE
FRONT WHICH COULD BRIEFLY CHANGEOVER TO SNOW BEFORE ENDING...
PRIMARILY N OF HWY 6. PRECIP WILL INITIALLY STRUGGLE TO REACH THE
GROUND. THE ENVIRONMENT IS NOT FAVORABLE FOR MUCH MEASURABLE
PRECIP.
THE LOWEST CONFIDENCE PORTION OF THE FCST IS TEMPS. WE COULD BE
TOO COOL. MULTIPLE OVERNIGHT CYCLES OF THE RAP SUGGEST 50F UP TO
I-80 AND NEARING 60 OVER N-CNTRL KS. I COULD ONLY ENVISION THAT
HAPPENING WITH FULL SUN AND THAT IS NOT EXPECTED. USED CONSENSUS
OF HI-RES SHORT-TERM MODELS FOR HIGHS AND THEN NUDGED HIGHS MORE
INTO THE 50S OVER N-CNTRL KS IN COORDINATION WITH KS OFFICES.
TEMPS WILL FALL THIS AFTERNOON N OF I-80 BEHIND THE FRONT.
WINDS: BLENDED THE 18Z/00Z MAV MOS 50-50. N WINDS WILL HOWL...
GUSTING 45-50 MPH IN THE TIGHT PRES GRADIENT/CAA BEHIND THE LOW. 6
HR PRES RISES OF 12 MB ARE LIKELY.
TONIGHT: CLOUDY...WINDY AND TURNING VERY COLD. WINDS WILL BE
STRONGEST PRIOR TO MIDNIGHT. TEMPS PLUMMET INTO THE SINGLE DIGITS
OVER N-CNTRL NEB AND LINGERING WINDS WILL PUSH WIND CHILLS AS LOW
AS -20F.
CAA WILL RESULT IN SOME MODEST INSTABILITY IN THE LINGERING
STRATUS WHICH WILL COOL INTO THE IDEAL SNOW GROWTH LAYER. SO KEPT
THE MENTION OF FLURRIES FROM THE PREVIOUS FCST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 504 AM CST WED FEB 25 2015
THE MAIN FORECAST CONCERN IS THE CHANCE FOR SNOW OVER THE WEEKEND
AND INTO EARLY NEXT WORK WEEK.
WE START OUT THE LONG TERM FORECAST THURSDAY WITH AN EXPANDING
SURFACE RIDGE BUILDING IN. MODEL SOUNDINGS INDICATE THAT WE COULD
HANG ON TO SOME STRATUS A LITTLE LONGER THAN WHAT OUR INITIALIZED
SUPERBLEND ADVERTISES AND I HAVE BUMPED UP SKY COVER. MODELS ARE
IN GOOD AGREEMENT WITH 850 MB TEMPERATURES IN THE -165 TO -20
RANGE FOR THURSDAY...WE WILL STRUGGLE TO GET HIGHS IN THE TEENS
FOR MOST AREAS. WE MAY MAKE IT TO AROUND 20 IN OUR SOUTH. I USED
THE NAM FOR HIGH TEMPERATURES...BUT THIS IS DEPENDING ON WIND
SPEEDS STAYING UP A BIT. GFS ACTUALLY INDICATES SOME AREA IN OUR
NORTHEAST NOT BREAKING INTO THE TEENS FOR HIGHS...AND THIS MAY
VERY WELL HAPPEN...ESPECIALLY IF WIND SPEED DROPS AND WE GET A
LITTLE MORE SKY COVER HANGING AROUND.
THE 1040 MB HIGH WILL BE CENTERED OVER THE NORTHERN PLAINS BY
THURSDAY EVENING AND WILL CONTINUE MOVING SOUTH SOUTHEAST.
THURSDAY WILL FEEL QUITE COLD. WIND CHILLS MAY BRIEFLY BREAK INTO
THE SINGLE DIGITS FOR THE AFTERNOON BEFORE MAKING ANOTHER DIVE.
WIND SPEED COULD BE JUST STRONG ENOUGH THURSDAY NIGHT TO KEEP WIND
CHILLS IN THE -15 TO -20 RANGE IN OUR NORTHEAST. WIND SPEEDS
SHOULD DIMINISH LATE AS THE CENTER OF THE SURFACE HIGH SLIDES
NEARER...MAYBE AS CLOSE AS EASTERN NEBRASKA. THIS WILL CAUSE WIND
TO DROP OFF QUITE A BIT AND WITH ANTICIPATED MOSTLY CLEAR SKY FOR
MUCH OF THE CWA...WE COULD WIND UP BEING BELOW ZERO FOR A
CONSIDERABLE PORTION OF THE CWA. ORD COULD REALLY TANK TO NEAR
-10. NUMERICAL MODELS ARE ALL TRENDING COLDER FOR THURSDAY
NIGHT/FRIDAY MORNING AND I HAVE CONTINUED THIS TREND. I BUMPED
DOWN TEMPERATURES CONSIDERABLY COMPARED TO SUPERBLEND
INITIALIZATION. WE MAY HOLD NEAR ZERO IN OUR SOUTH/SOUTHWEST WHERE
WE MAY HAVE A FEW MORE CLOUDS AROUND ALONG WITH SLIGHTLY STRONGER
WIND SPEED.
NUMERICAL MODELS ALL TEND TO KEEP US DRY FRIDAY/FRIDAY NIGHT FOR
THE MOST PART...WITH THE EXCEPTION OF PERHAPS SOME FLURRIES IN
ADVANCE OF THE NEXT WINTER SYSTEM ARRIVING FOR THE WEEKEND.
A POSITIVELY TILTED MEAN TROUGH DEVELOPS IN THE WESTERN UNITED
STATES AND LONG RANGE MODELS ARE CONSISTENT AND CONGRUENT WITH
THIS SYNOPTIC FEATURE. THIS SETS UP A COLD AND UNSETTLED PATTERN
FOR US WITH THE SOUTHERN STREAM SOUTHWEST FLOW AND IMPULSES OF
ENERGY FROM SATURDAY THROUGH MONDAY NIGHT THAT COULD GIVE US MORE
THAN ONE ROUND OF MEASURABLE SNOWFALL. FOR NOW...THE CURRENT TRACK
WOULD PLACE MORE SNOW CHANCES IN OUR SOUTHERN CWA...BUT AS WE ALL
KNOW...THINGS MAY TREND ONE WAY OR ANOTHER...ESPECIALLY AS WE ARE
3 TO 5 DAYS AWAY. I DID BUMP UP PRECIPITATION CHANCES A BIT MORE
FOR SATURDAY AND SATURDAY NIGHT AS MODELS CONTINUE TO PAINT
CONSIDERABLE QPF FOR US...ESPECIALLY IN OUR SOUTH. THIS STILL
LOOKS AT LEAST LIKE A POTENTIAL WINTER WEATHER ADVISORY SITUATION
...BUT WE STILL HAVE SOME TIME BEFORE THIS ARRIVES AND WE SHOULD
GET A BETTER HANDLE OF THIS WITH TIME.
I WENT CLOSER TO CONSRAW FOR HIGH TEMPERATURES FRIDAY INTO MONDAY
...WHICH WAS GENERALLY PRETTY CLOSE TO SUPERBLEND...EXCEPT FOR
MONDAY WHICH BUMPED TEMPERATURES DOWN A BIT FROM INITIALIZED
GRIDS. THIS WOULD MAKE SENSE...ESPECIALLY IF THERE ENDS UP BEING
SNOW ON THE GROUND. I DO NOT SEE AN END TO WELL BELOW NORMAL
TEMPERATURES ANYTIME SOON...WITH WELL BELOW TEMPERATURES EXPECTED
INTO EARLY MARCH UNDER THIS CONSISTENTLY COLD PATTERN.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1123 AM CST WED FEB 25 2015
THE FIRST BAND OF PRECIPITATION HAS MOVED THROUGH THE TERMINALS
BUT THERE IS A LITTLE BIT BEHIND THE MAIN BAND. TEMPERATURES HAVE
BEEN FALLING AND SO THERE MAY BE A LITTLE SPRINKLE OR FLURRIES FOR
A TIME THIS AFTERNOON. HAVE LEFT IT OUT OF KEAR...BUT THERE COULD
BE A STRAY FLURRY EARLY THIS AFTERNOON. THE WINDIEST PERIOD WILL
BE THIS AFTERNOON...BUT BREEZY CONDITIONS ARE EXPECTED THROUGH THE
PERIOD. LOW CLOUDS WILL MOVE OUT OF THE AREA OVERNIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...HEINLEIN
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1130 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 216 AM CST WED FEB 25 2015
INITIAL CONCERN WILL BE TYPE AND EXTENT OF PRECIP AS SURFACE LOW
TRACKS ACROSS THE AREA TODAY. THEN COLD AND WINDY CONDITIONS WITH
SUBZERO WIND CHILLS APPROACHING CRITERIA THURSDAY MORNING. JUST
PLAIN COLD FRIDAY MORNING.
SURFACE LOW WAS LOCATED OVER SOUTH CENTRAL SOUTH DAKOATA AT 08Z
WITH PRIMARY BAND OF PRECIP FROM EASTERN SOUTH DAKOTA INTO
SOUTHWEST MINNESOTA AND NORTHWEST IOWA. BOTH THE HRRR AND RAP
SLOWER IN BRINGING THE PRECIP SHIELD SOUTH TODAY WITH PRIMARY BAND
STRETCHING ACROSS NORTHERN IOWA THROUGH THE MORNING. HAVE ADJUSTED
TIMING OF THE WINTER WEATHER ADVISORY TO ACCOUNT FOR THIS FEATURE
AND ALSO REMOVED THE TWO SOUTHWEST IOWA COUNTIES AS TEMPERATURES
ARE EXPECTED TO REMAIN ON THE WARM SIDE THERE FOR MOST OF THE DAY
WITH BETTER QPF EAST OF THE AREA.
HAVE TRENDED TEMPERATURES WARMER ACROSS THE SOUTH HALF OF THE AREA
AND BACKED OFF FURTHER ON PRECIP AND SNOW ACROSS THE SOUTH.
TEMPERATURES WILL BE TRICKY TODAY AND DEPEND ON TIMING OF THE COLD
AIR BEHIND THE FRONT THIS AFTERNOON AS THE LOW TRACKS ACROSS EAST
CENTRAL NEBRASKA TOWARD NORTHWEST MISSOURI. A PERIOD OF MIXED
PRECIP...WHICH COULD INCLUDE FREEZING RAIN...IS POSSIBLE FOR A
TIME THIS MORNING IN PARTS OF NORTHEAST NEBRASKA INTO WEST CENTRAL
IOWA BEFORE THE COLD AIR MOVES IN BEHIND THE FRONT. AMOUNTS SHOULD
BE LIGHT WITH LIMITED AREAL COVERAGE.
THE ARCTIC AIR SPREADS RAPIDLY SOUTH TONIGHT ALONG WITH GUSTY
NORTHWEST WINDS. SUBZERO WIND CHILLS ARE LIKELY ACROSS THE AREA BY
THURSDAY MORNING WITH NORTHERN COUNTIES APPROACHING ADVISORY
CRITERIA. WILL COVER THE COLD IN HWO FOR NOW BUT ADVISORY LOOKS
LIKELY IN LATER FORECASTS. WINDY AND COLD CONDITIONS WILL EXTEND
THROUGH THE DAY ON THURSDAY WITH WINDS DIMINISHING THURSDAY
EVENING. TEMPERATURES ARE EXPECTED TO PLUNGE BELOW ZERO THURSDAY
NIGHT AS HIGH SETTLES OVER THE AREA AND WINDS BECOME LIGHT. SLOW
WARMING???? ON FRIDAY AS HIGH MOVES EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 216 AM CST WED FEB 25 2015
LITTLE CHANGE TO GENERAL TRENDS. WEEKEND SYSTEM STILL KEEPS MAIN
PRECIP AXIS TO THE SOUTH WITH LIGHTER AMOUNTS FOR THE SOUTH HALF
OF THE CWA. MORE SIGNIFICANT SNOW POSSIBLE MONDAY INTO TUESDAY AS
MAIN WAVE COMES INTO THE PLAINS REGION.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1123 AM CST WED FEB 25 2015
ACTIVE FIRST FEW HOURS OF TAF PERIOD...THEN CONDITIONS WILL BEGIN
TO SLOWLY IMPROVE. KOFK...BAND OF SNOW IS ABOUT THROUGH THE SITE.
MVFR CIGS ARE EXPECTED THROUGH 00Z THEN CONDITIONS WILL CONTINUE
TO IMPROVE. KOMA...FRONT IS JUST ABOUT TO THE SITE AS IS THE
BEGINNING EDGE OF PCPN. RAIN EXPECTED INITIALLY WITH A CHANGE OVER
TO RA/SN FOR AN HOUR OR SO BEFORE THE TRANSITION OVER TO ALL SNOW.
THE SNOW SHOULD BE BRIEF...ONLY AN HOUR...WITH A FEW FLURRIES
LINGERING INTO THE LATER PART OF THE AFTERNOON AND DRYING OUT
THEREAFTER. CIGS SHOULD REMAIN MVFR INTO THE EVENING HOURS. KLNK...FRONT
EDGE OF PCPN BAND IS ALMOST TO THE SITE WITH LIGHT RAIN EXPECTED.
THERE MAY BE A BRIEF MIX OF RA/SN MID AFTERNOON. THIS SHOULD BE
SHORT LIVED AND OUT OF THE AREA LATE THIS AFTERNOON WITH
CONDITIONS IMPROVING THEREAFTER. FOR ALL SITES...GUSTY
NORTH/NORTHWEST WINDS BEHIND THE FRONT ARE EXPECTED TO REMAIN
THROUGH THE OVERNIGHT.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...WINTER WEATHER ADVISORY UNTIL 8 PM CST THIS EVENING FOR IAZ055-
056.
WINTER WEATHER ADVISORY UNTIL 8 PM CST THIS EVENING FOR IAZ069.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043.
&&
$$
SHORT TERM...FOBERT
LONG TERM...FOBERT
AVIATION...KERN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
320 PM EST WED FEB 25 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE MOVES QUICKLY FROM THE NORTHERN
GULF OF MEXICO...TO OFF THE CAROLINA COAST OVERNIGHT THROUGH EARLY
THURSDAY. COLD CANADIAN HIGH PRESSURE THEN BUILDS INTO THE REGION
FRIDAY AND INTO THE WEEKEND.
&&
.NEAR TERM /TODAY THROUGH THURSDAY/...
AS OF 150 PM WEDNESDAY...
...WINTER STORM WARNING HAS BEEN ISSUED FOR TONIGHT AND THURSDAY FOR
ALL THE PIEDMONT...NORTHERN/CENTRAL COASTAL PLAIN AND SANDHILLS...
...WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR TONIGHT AND THURSDAY
FOR THE SOUTHERN COASTAL PLAIN...
MORNING UPPER AIR ANALYSIS SHOWS THE SHEARING SHORT WAVE TROUGH OVER
TEXAS THIS MORNING WITH SHORT WAVE RIDGING OUT AHEAD OF IT ACROSS
THE SOUTHEAST. HIGH CLOUDS HAVE BEEN ADVANCING NORTHEAST AHEAD OF
THE SYSTEM AND MOST OF CENTRAL NC IS ALREADY UNDER AT LEAST A THIN
VEIL OF CIRRUS. REGIONAL RADAR IMAGERY SHOWS PRECIPITATION EXPANDING
ACROSS THE DEEP SOUTH WITH MEASURABLE PRECIP NOW REPORTED ACROSS
CENTRAL ALABAMA. NO PRECIPITATION IS EXPECTED IN CENTRAL NC DURING
THE TODAY PERIOD BUT TODAYS WEATHER COULD STILL PLAY A ROLE IN THE
IMPACT OF TONIGHTS WINTER STORM. THE TEMPERATURES FORECAST FOR TODAY
IS PROBLEMATIC AS YESTERDAYS SNOWFALL WILL DAMPEN THE TEMPERATURE
RECOVERY THIS AFTERNOON AND ENERGY IS DIVERTED INTO MELTING AND
EVAPORATING SNOW AND MELT WATER. EVEN SO...SOME GUIDANCE INCLUDING
THE HRRR SUGGEST HIGHS IN THE MID 40S TO AROUND 50. NOT READY TO
JUMP THAT HIGH BUT CURRENT TEMP AT OUR OFFICE IS 37 AT 1045 AND HAVE
MADE A SLIGHT UPWARD ADJUSTMENT IN TEMPERATURES FOR TODAY. THIS
UPWARD TREND IN BOUNDARY LAYER TEMPERATURES WOULD DELAY THE
CHANGEOVER FROM RAIN OR MIXED RAIN AND SNOW THIS EVENING TO SNOW AND
POTENTIALLY LIMIT ACCUMULATIONS A BIT...PRIMARILY ACROSS THE FAR
SOUTHERN TIER IN THE SANDHILLS AND SOUTHERN COASTAL PLAIN. -BLAES
THERE HAS BEEN A CONTINUED SLIGHT NORTHWARD SHIFT IN GUIDANCE SINCE
YESTERDAY...WHICH EQUATES TO A WETTER AND MARGINALLY WARMER SOLUTION
FOR CENTRAL NC...THOUGH THE OVERALL PATTERN REMAINS UNCHANGED WITH
THE DEAMPLIFICATION/ENE SHEARING OF A SHORTWAVE TROUGH FROM NEAR THE
RIO GRANDE THIS MORNING TO THE MIDDLE ATLANTIC COAST BY THU MORNING.
THE ASSOCIATED FORCING FOR ASCENT ATOP A PAIR OF CLOSELY-SPACED AND
STRONG FRONTAL ZONES DRAPED ACROSS THE NORTHERN GOM TO A SFC LOW
ABOUT MIDWAY BETWEEN CAPE HATTERAS AND BERMUDA...WILL RESULT IN THE
CONTINUED DEEPENING OF A SFC LOW OVER THE NW GOM THIS MORNING.
GUIDANCE IS THEN FAIRLY TIGHTLY CLUSTERED WITH THE TRACK OF A MILLER
"A" SFC LOW ACROSS THE NORTHERN FL PENINSULA THIS EVENING AND
ROUGHLY ALONG THE GULF STREAM TO JUST EAST OF CAPE HATTERAS BY 12Z
THU.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS...THE LACK OF A PARENT
COLD HIGH IS ADMITTEDLY SOMEWHAT CONCERNING. AN ARCTIC SFC HIGH AT
1045 MB WILL BE CENTERED OVER SOUTHERN ALBERTA/SASKATCHEWAN AND WILL
CONSEQUENTLY HAVE LITTLE INFLUENCE AT OUR LATITUDE DURING THE HEIGHT
OF THE STORM TONIGHT. HOWEVER...A VERY FAVORABLE MILLER "A" CYCLONE
TRACK ALONG AND JUST OFFSHORE THE SE COAST...IN CONJUNCTION WITH A
PRECEDING ARCTIC HIGH THAT APPEARS TO BE JUST COLD ENOUGH DESPITE
BEING IN A DRAMATICALLY WEAKENED STATE FROM A COUPLE OF DAYS
AGO...BUT IS STILL CHARACTERIZED BY SFC TEMPERATURES AND DEWPOINTS
MOSTLY IN THE TEENS TO 20S OVER NC THIS MORNING...WILL SUPPORT A
SIGNIFICANT WINTER STORM **WITH A NARROW P-TYPE (SNOW/RAIN)
TRANSITION ZONE AND DEEP NEAR FREEZING ISOTHERMAL PROFILES
CHARACTERISTIC OF MILLER "A` SFC PATTERNS.** PRECIPITATION
RATES...OCCASIONALLY MODERATE TO HEAVY...WILL ONLY SERVE TO ENHANCE
THE DEEP NEAR FREEZING ISOTHERMAL PROFILES RIGHT ALONG THE SNOW/COLD
RAIN INTERFACE...OWING TO MELTING. A LITTLE MIX OF SLEET AND
FREEZING RAIN ARE HARD TO AVOID IN CENTRAL NC WINTER STORMS...AND IN
MILLER "A" STORMS INCLUDING THIS ONE...SUCH OCCURRENCE IS MOST
LIKELY NEAR THE NARROW TRANSITION SNOW/RAIN ZONE. NO APPRECIABLE
ICING IS ANTICIPATED...HOWEVER...IN PART SINCE SURFACE TEMPERATURES
ARE EXPECTED TO HOLD NEARLY STEADY IN THE 29 TO 33 DEGREE RANGE OVER
THE WARNING AREA...AND 32 TO 34 DEGREES OVER THE ADVISORY AREA WHERE
SUCH ICING OCCURRENCE WOULD BE MOST PROBABLE.
DESPITE SOME MINIMAL OVERALL RISE IN THICKNESS VALUES VERSUS THE
SLIGHTLY COLDER AND DRIER SOLUTIONS OF YESTERDAY...PROJECTED PARTIAL
THICKNESS VALUES OVER MOST OF THE PIEDMONT AND NORTHERN COASTAL
PLAIN REMAIN SQUARELY IN THE RANGE TYPICAL OF SIGNIFICANT SNOWSTORMS
IN CENTRAL NC. WITH A SLIGHTLY MILDER SOLUTION COMES A SLIGHTLY
WETTER ONE...LED BY A BLEND OF THE VERY SIMILAR 00Z ECMWF AND
GFS...SO QPF HAS BEEN RAISED TO AROUND ONE HALF INCH OVER THE NW
PIEDMONT TO AS MUCH AS ONE INCH OVER THE SOUTHERN COASTAL PLAIN.
PARTIAL THICKNESS VALUES HEAVILY WEIGHTED TOWARD THE FAVORED 00Z
ECMWF AND GFS...FAVORS MOSTLY SNOW OVER THE PIEDMONT AND NORTHERN
COASTAL PLAIN...WITH A MIX OF SNOW AND A COLD RAIN (OR FREEZING RAIN
WITH LITTLE ACCRUAL WHERE SFC TEMPERATURES OSCILLATE ABOUT THE
FREEZING MARK) OVER THE ADVISORY AREA.
SNOW RATIOS BETWEEN 00-06Z THU OF 10-14:1 PER WPC WWD SLR GUIDANCE
AND SUPPORTED BY THERMAL PROFILES THAT RANGE FROM DEEP NEAR FREEZING
ISOTHERMAL IN THER NARROW TRANSITION ZONE TO WELL BELOW FREEZING...
EXCEPT RIGHT AT THE SURFACE...ALONG AND NORTH OF THE I-40/I-85
CORRIDOR...ARE EXPECTED TO DECREASE PARTICULARLY NEAR NARROW
TRANSITION ZONE TO CLOSER TO 8-10:1 PER WHAT IS TYPICAL OF EVENTS
CHARACTERIZED BY PARTIAL THICKNESS VALUES IN THE ~1285/~1535 METER
RANGE. SLIGHTLY LOWER RATIOS...CLOSER TO 4-6:1 WITHIN THE SNOW/RAIN
TRANSITION ZONE - OR ROUGHLY ALONG THE BOUNDARY OF WINTER STORM
WARNING AND WINTER WEATHER ADVISORY - WHERE THE MIXING WITH A COLD
RAIN WILL RESULT IN A MORE SLUSHY ACCUMULATION VERSUS POINTS
NORTHWARD.
BASED ON THESE RATIOS...AND THE QPF NOTED ABOVE...WIDESPREAD
SNOWFALL ACCUMULATIONS OF 3 TO 6 INCHES ARE LIKELY OVER THE WARNING
AREA...WITH A STRIPE OF 6 TO 8 INCHES ROUGHLY INVOF OR JUST NORTH OF
THE US HIGHWAY 64 CORRIDOR...WITH LOCALLY HIGHER AMOUNTS FROM THE
TRIANGLE TO ROANOKE RAPIDS AND ROCKY MOUNT. MEANWHILE...LESSER
TOTALS OF 1 TO 3 INCHES ARE EXPECTED OVER THE ADVISORY AREA...WHERE
AGAIN...PARTIAL THICKNESS AND SFC TEMPERATURE VALUES MARGINALLY
ABOVE FREEZING WILL SUPPORT A MIXING WITH OR CHANGEOVER TO A COLD
RAIN BETWEEN MIDNIGHT AND 5 AM. EVEN THERE...HOWEVER...THE NORTHERN
PORTIONS OF THE ADVISORY COUNTIES MAY EXCEED WARNING CRITERIA OF 3
INCHES.
THE APPROACH OF A WEAK CLIPPER LOW AND ATTENDING SHORTWAVE TROUGH
WILL CAUSE THE LINGERING STRATUS LAYER AND ASSOCIATED MOSTLY CLOUDY
SKIES TO PRODUCE OCCASIONAL DRIZZLE OR FREEZING DRIZZLE...AFTER
LINGERING LIGHT SNOW...OWING TO A LOSS OF SATURATION ALOFT/IN THE
ICE NUCLEATION ZONE - BUT WITH MINIMAL ADDITIONAL IMPACT. CHILLY
TEMPERATURES IN THE LOWER TO MIDDLE 30S.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 320 PM WEDNESDAY...
A MID-LEVEL SHORTWAVE IS FORECAST BY BOTH THE GFS AND THE NAM TO
MOVE THROUGH CENTRAL NORTH CAROLINA THURSDAY EVENING...WITH ANOTHER
WEAK WAVE ON FRIDAY. LOW-LEVEL MOISTURE REMAINS IN PLACE OVERALL...
HIGHLIGHTED BY MODEST VALUES OF MEAN RELATIVE HUMIDITY IN THE 1000-
500MB LAYER AS SURFACE HIGH PRESSURE GRADUALLY BUILDS IN. 850MB
THETA-E IS GENERALLY LOW DURING THE PERIOD WITH PRECIPITABLE WATER
VALUES AT OR JUST BELOW NORMAL FOR LATE FEBRUARY...HOWEVER...VIEWING
THE NAM AND GFS BUFR SOUNDINGS...AGAIN...LOW-LEVEL MOISTURE REMAINS
WITH SOME MOISTURE SATURATION AT TIMES TO AT OR JUST COLDER THAN -
10C. THE GFS IN PARTICULAR PROVIDES FOR MARGINAL MEASURABLE
PRECIPITATION IN THE FAR NORTHWEST PIEDMONT OVERNIGHT THURSDAY...
AND THEN MAINLY ALONG AND WEST OF U.S. 1 FRIDAY SHIFTING BACK WEST
AGAIN FRIDAY NIGHT INTO EARLY SATURDAY. IT IS DURING THESE PERIODS
THAT BUFR SOUNDINGS FORECAST MOISTURE TO A LEVEL IN ATMOSPHERE
COLDER THAN -10C.
LIFT IS MARGINAL DURING THIS SHORT-TERM PERIOD...LIKELY BEST ON
FRIDAY WHEN BUFR SOUNDINGS SHOW LOW-LEVEL LAPSE RATES STEEPENING AND
THE COMBINATION OF 850MB CONVERGENCE AND UPPER-LEVEL DIVERGENCE IS
BEST MAINLY OVER THE FAR NORTHWEST PIEDMONT OVERNIGHT THURSDAY AND
ALONG AND WEST OF U.S. 1 FRIDAY. GIVEN THE LOW-LEVEL MOISTURE AND
MODEST SUPPORT ALOFT WITH THE MID-LEVEL SHORTWAVES...IN ADDITION TO
THE GFS VERY LIGHT QPF AND SOME NOTICE OF LIGHT PRECIPITATION OUTPUT
ON THE NCEP HIGH RES NMMB...HAVE OPTED TO INCLUDE A SLIGHT CHANCE OF
FLURRIES MAINLY IN THE FAR NORTHWEST PIEDMONT THURSDAY NIGHT...WITH
A SLIGHT CHANCE OF SNOW SHOWERS THERE FRIDAY WHERE BUFR SOUNDINGS
ESPECIALLY ON THE GFS SHOW THE LAPSE RATES STEEPENING. A SLIGHT
CHANCE OF FLURRIES ELSEWHERE FRIDAY TO NEAR U.S. 1 OR SO...THEN A
SLIGHT CHANCE OF FLURRIES FRIDAY NIGHT ALONG AND NORTH OF A LINE
FROM ABOUT KRWI TO KAFP. BY SATURDAY MORNING...BUFR SOUNDINGS SHOW
ENOUGH DRYING THAT ANY FLURRIES THAT EXIST SHOULD ONLY BE LOCATED
OVER THE FAR NORTHWEST PIEDMONT. TOWARD KFAY...BUFR SOUNDINGS FROM
THE GFS AND NAM DO NOT SHOW DEEPER LOW-LEVEL MOISTURE GETTING TO OR
COLDER THAN -10C...SO HAVE NOT MENTIONED ANY FLURRIES THERE THIS
PERIOD. CURRENTLY THINK THERE SHOULD BE LITTLE OR NO IMPACT AS THE
PRECIPITATION SHOULD BE VERY LIGHT IF IT OCCURS...THOUGH STILL
NOTICEABLE. SATURDAY DURING THE DAY...HIGH PRESSURE CONTINUES TO
BUILD IN.
AFTER LOWS THURSDAY NIGHT IN THE 20S...HIGHS FRIDAY SHOULD RANGE
WITHIN A DEGREE OR THREE EITHER SIDE OF 40...CLOSE TO WHAT WOULD BE
ASSOCIATED WITH THE 1000-850MB THICKNESSES. LOWS FRIDAY NIGHT IN THE
UPPER TEENS TO MID 20S...A BLEND OF GUIDANCE BASED ON CONTINUED
CLOUD COVER. ON SATURDAY...A LITTLE COLDER THAN FRIDAY DUE TO COLDER
THICKNESSES TO START THE DAY AND THE HIGH BUILDING IN...MOSTLY MID
30S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 1200 PM WEDNESDAY...
THE LONG-TERM SATURDAY NIGHT THROUGH WEDNESDAY IS CATEGORIZED BY
SOME UNCERTAINTY IN PRECIPITATION TIMING AND TYPE...WITH AT LEAST
MODEST CONFIDENCE IN MUCH WARMER TEMPERATURES DEVELOPING BY THE END
OF THIS PERIOD THAN WHAT HAS BEEN OCCURRING RECENTLY. DRYING IS
FORECAST FOR SATURDAY NIGHT...WITH A MID-LEVEL SHORTWAVE MOVING INTO
THE CAROLINAS BY SUNDAY NIGHT. AS HEIGHTS ALOFT RISE LATE IN THE
WEEKEND AND EARLY NEXT WEEK...THE 06Z GFS IN PARTICULAR AND POSSIBLY
EVEN THE 12Z GFS SEEMS TO HAVE ISSUES WITH FEEDBACK SUCH THAT THE
ECMWF IS PREFERRED OVERALL. IT SHOULD BE COLD TO START SUNDAY
MORNING AS CLOUDS INCREASE...BUT THE GFS AND ECMWF TREND OF A LATER
ARRIVAL OF MID-LEVEL VORTICITY AND OVERALL MOISTURE INCREASE SHOULD
RESULT IN PRECIPITATION BEING IN THE FORM OF LIQUID BY THE TIME ANY
WOULD ARRIVE LATER IN THE DAY. PARTIAL THICKNESSES AND MODEL
SOUNDINGS CURRENTLY SUPPORT THIS...AND WILL HAVE A CHANCE OF
AFTERNOON RAIN SUNDAY PRIMARILY TOWARD THE YADKIN RIVER FOLLOWED BY
CHANCES OF RAIN OVERNIGHT...WITH SURFACE TEMPERATURES REMAINING
ABOVE FREEZING AND MODEL SOUNDINGS SHOWING WARMING ALOFT AS 1000-
850MB THICKNESSES RISE AROUND 20M DURING THE NIGHT...SUGGESTING THE
POTENTIAL FOR LOW TEMPERATURES EARLY SUNDAY NIGHT FOLLOWED BY STEADY
OR A SLOW RISE IN READINGS LATE.
A BRIEF WARMUP OCCURS MONDAY AHEAD OF A COLD FRONT THAT MOVES
THROUGH CENTRAL NORTH CAROLINA LATER IN THE DAY AND AT NIGHT. STRONG
HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT...AND THE PATTERN
WOULD SUGGEST PRETTY CHILLY TEMPERATURES ONCE AGAIN WITH THE 1000-
850MB THICKNESSES SUGGESTING LOWS A LITTLE BELOW FREEZING. MOS
GUIDANCE LOWS ARE AT LEAST ONE IF NOT MORE CATEGORIES ABOVE THIS...
SO FOR NOW WILL SIMPLY UNDERCUT GUIDANCE WITH OVERNIGHT LOWS AT OR
SLIGHTLY ABOVE FREEZING. CONDITIONS SHOULD DRY BRIEFLY BEHIND THE
FRONT AS HIGH PRESSURE BUILDS IN...THEN UNCERTAINTY INCREASES AS THE
GFS AND THE ECMWF SUGGEST MOISTURE RETURNING TO CENTRAL NORTH
CAROLINA AS THE GULF OPENS BY TUESDAY INTO TUESDAY NIGHT. IF
PRECIPITATION WOULD RETURN TO CENTRAL NORTH CAROLINA QUICKLY ENOUGH
ON TUESDAY...PRECIPITATION TYPE CONCERNS WOULD EXIST DUE TO CHILLY
THICKNESSES TO START THE DAY. BY 00Z WEDNESDAY ON THE 12Z GFS...AND
FOR THE MOST PART ON THE 00Z ECMWF...THICKNESSES ARE WARM ENOUGH FOR
RAIN AND BASED ON THE WARM-AIR ADVECTION AT THE TIME WOULD
ANTICIPATE ANOTHER POTENTIAL NON-DIURNAL TEMPERATURE SCENARIO AS ANY
COLD-AIR DAMMING ERODES. BASED ON THE PATTERN WILL ONLY NOTE A
SLIGHT CHANCE OF RAIN OR SNOW EARLY ON THE SIXTH DAY IN THE WESTERN
PIEDMONT WITH A CHANCE OF JUST ALL RAIN THROUGHOUT CENTRAL NORTH
CAROLINA BY TUESDAY AFTERNOON. 1000-850MB THICKNESSES ON THE 12Z GFS
AND 00Z ECMWF ARE QUITE WARM WEDNESDAY...APPROACHING 1380M ON THE
LATEST GFS AND ONLY SLIGHTLY COOLER ON THE 00Z ECMWF...SUCH THAT...
WITH SHOWERY CONDITIONS IN A MOIST AIR MASS AND A SOUTHWEST FLOW
ALOFT...HIGH TEMPERATURES COULD POSSIBLY REACH THE 60S THROUGHOUT
CENTRAL NORTH CAROLINA WITH SOME TEMPERATURES PUSHING 70F ESPECIALLY
OVER PARTS OF THE SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1255 PM WEDNESDAY...
FOR THE 18Z VALID TAF PERIOD...HIGH CONFIDENCE IN VFR CONDITIONS FOR
THE REST OF THIS AFTERNOON DETERIORATING QUICKLY TO IFR AND SUB-IFR
CONDITIONS THIS EVENING...CONTINUING OVERNIGHT. GUIDANCE SUGGESTS
PRECIPITATION MOVING SOUTHWEST TO NORTHEAST INTO AND ACROSS CENTRAL
NORTH CAROLINA FROM VERY LATE THIS AFTERNOON THROUGH THIS EVENING...
WITH PRECIPITATION ACROSS THE AREA BY 03Z. MODEL SOUNDINGS FROM THE
NAM AND GFS SUGGEST WHATEVER LIQUID PRECIPITATION THERE MAY BE TO
START CHANGING QUICKLY TO SNOW...WITH ENOUGH WARMING ALOFT THAT A
PRECIPITATION TYPE OF SNOW AND SLEET IS QUITE POSSIBLE AT KRDU AND
KRWI. AT KFAY...THE ABOVE FREEZING DEPTH IS A LITTLE HIGHER AND
LIGHT RAIN MAY LINGER A LITTLE LONGER AT THE START BEFORE A
TRANSITION TO SNOW...SLEET...AND FREEZING RAIN...WITH THE NAM MODEL
MOST SUGGESTIVE OF WARMTH ALOFT FOR FREEZING RAIN AND MAINLY FOR A
COUPLE OR THREE HOURS CENTERED AROUND 06Z. DRYING ALOFT VERY LATE
TONIGHT INTO THURSDAY MORNING SUGGEST PRECIPITATION CHANGING TO
FREEZING DRIZZLE OR DRIZZLE...WITH IFR CONDITIONS CONTINUING IN LOW
CLOUDS. VARIABLE WINDS THIS AFTERNOON BECOME NORTH-NORTHEAST AND
NORTHEAST THIS EVENING AS LOW PRESSURE GETS CLOSER AND MOVES
NORTHEAST ALONG THE ATLANTIC COAST.
BEYOND THE 18Z VALID TAF PERIOD...CONFIDENCE DIMINISHES IN
IMPROVEMENT FROM IFR CONDITIONS...WITH AVIATION INTERESTS BEING
PREPARED FOR THE LIKELIHOOD OF SUB-VFR CONDITIONS THROUGH THURSDAY
NIGHT ALBEIT WITH A FEW PERIODS OF VFR CONDITIONS POSSIBLE MAINLY
THURSDAY NIGHT. SUB-VFR CONDITIONS REMAIN POSSIBLE IN LOW CLOUDS
THROUGH FRIDAY WITH A GREATER LIKELIHOOD OF VFR CONDITIONS FOR
FRIDAY NIGHT. VFR CONDITIONS EXPECTED SATURDAY WITH CLOUDS
INCREASING AND LOWERING FOR SUNDAY...THEN SUB-VFR CONDITIONS LIKELY
FOR SUNDAY NIGHT INTO MONDAY ALONG WITH CHANCES FOR PRECIPITATION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST THURSDAY
FOR NCZ078-085-086-088-089.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON EST THURSDAY FOR
NCZ007>011-021>028-038>043-073>077-083-084.
&&
$$
SYNOPSIS...RAH
NEAR TERM...BLAES/RAH
SHORT TERM...DJF
LONG TERM...DJF
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 PM EST WED FEB 25 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE MOVES QUICKLY FROM THE NORTHERN
GULF OF MEXICO...TO OFF THE CAROLINA COAST OVERNIGHT THROUGH EARLY
THURSDAY. COLD CANADIAN HIGH PRESSURE THEN BUILDS INTO THE REGION
FRIDAY AND INTO THE WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 150 PM WEDNESDAY...
UPDATED THE DISCUSSION ONLY TO REMOVE MENTION OF THE EARLIER
ADVISORY.
MORNING UPPER AIR ANALYSIS SHOWS THE SHEARING SHORT WAVE
TROUGH OVER TEXAS THIS MORNING WITH SHORT WAVE RIDGING OUT AHEAD OF
IT ACROSS THE SOUTHEAST. HIGH CLOUDS HAVE BEEN ADVANCING NORTHEAST
AHEAD OF THE SYSTEM AND MOST OF CENTRAL NC IS ALREADY UNDER AT LEAST
A THIN VEIL OF CIRRUS. REGIONAL RADAR IMAGERY SHOWS PRECIPITATION
EXPANDING ACROSS THE DEEP SOUTH WITH MEASURABLE PRECIP NOW REPORTED
ACROSS CENTRAL ALABAMA. NO PRECIPITATION IS EXPECTED IN CENTRAL NC
DURING THE TODAY PERIOD BUT TODAYS WEATHER COULD STILL PLAY A ROLE IN
THE IMPACT OF TONIGHTS WINTER STORM. THE TEMPERATURES FORECAST FOR
TODAY IS PROBLEMATIC AS YESTERDAYS SNOWFALL WILL DAMPEN THE
TEMPERATURE RECOVERY THIS AFTERNOON AND ENERGY IS DIVERTED INTO
MELTING AND EVAPORATING SNOW AND MELT WATER. EVEN SO...SOME
GUIDANCE INCLUDING THE HRRR SUGGEST HIGHS IN THE MID 40S TO AROUND
50. NOT READY TO JUMP THAT HIGH BUT CURRENT TEMP AT OUR OFFICE IS 37
AT 1045 AND HAVE MADE A SLIGHT UPWARD ADJUSTMENT IN TEMPERATURES FOR
TODAY. THIS UPWARD TREND IN BOUNDARY LAYER TEMPERATURES WOULD
DELAY THE CHANGEOVER FROM RAIN OR MIXED RAIN AND SNOW THIS EVENING
TO SNOW AND POTENTIALLY LIMIT ACCUMULATIONS A BIT...PRIMARILY
ACROSS THE FAR SOUTHERN TIER IN THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -BLAES
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS OF 1100 AM WEDNESDAY...
*** QUICK 1100 AM UPDATE. QUICK LOOK AT 12Z GUIDANCE NOTES NO
IMMEDIATE OR SIGNIFICANT FORECAST ADJUSTMENTS ARE NEEDED BUT NAM
CONTINUES TO TREND NORTH A BIT AND WITH THE GFS SHOWING A SLIGHT
NORTHWARD ADJUSTMENT.
...WINTER STORM WARNING HAS BEEN ISSUED FOR TONIGHT AND THURSDAY FOR
ALL THE PIEDMONT...NORTHERN/CENTRAL COASTAL PLAIN AND SANDHILLS...
...WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR TONIGHT AND THURSDAY
FOR THE SOUTHERN COASTAL PLAIN...
THERE HAS BEEN A CONTINUED SLIGHT NORTHWARD SHIFT IN GUIDANCE SINCE
YESTERDAY...WHICH EQUATES TO A WETTER AND MARGINALLY WARMER SOLUTION
FOR CENTRAL NC...THOUGH THE OVERALL PATTERN REMAINS UNCHANGED WITH
THE DEAMPLIFICATION/ENE SHEARING OF A SHORTWAVE TROUGH FROM NEAR THE
RIO GRANDE THIS MORNING TO THE MIDDLE ATLANTIC COAST BY THU MORNING.
THE ASSOCIATED FORCING FOR ASCENT ATOP A PAIR OF CLOSELY-SPACED AND
STRONG FRONTAL ZONES DRAPED ACROSS THE NORTHERN GOM TO A SFC LOW
ABOUT MIDWAY BETWEEN CAPE HATTERAS AND BERMUDA...WILL RESULT IN THE
CONTINUED DEEPENING OF A SFC LOW OVER THE NW GOM THIS MORNING.
GUIDANCE IS THEN FAIRLY TIGHTLY CLUSTERED WITH THE TRACK OF A MILLER
"A" SFC LOW ACROSS THE NORTHERN FL PENINSULA THIS EVENING AND
ROUGHLY ALONG THE GULF STREAM TO JUST EAST OF CAPE HATTERAS BY 12Z
THU.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS...THE LACK OF A PARENT
COLD HIGH IS ADMITTEDLY SOMEWHAT CONCERNING. AN ARCTIC SFC HIGH AT
1045 MB WILL BE CENTERED OVER SOUTHERN ALBERTA/SASKATCHEWAN AND WILL
CONSEQUENTLY HAVE LITTLE INFLUENCE AT OUR LATITUDE DURING THE HEIGHT
OF THE STORM TONIGHT. HOWEVER...A VERY FAVORABLE MILLER "A" CYCLONE
TRACK ALONG AND JUST OFFSHORE THE SE COAST...IN CONJUNCTION WITH A
PRECEDING ARCTIC HIGH THAT APPEARS TO BE JUST COLD ENOUGH DESPITE
BEING IN A DRAMATICALLY WEAKENED STATE FROM A COUPLE OF DAYS
AGO...BUT IS STILL CHARACTERIZED BY SFC TEMPERATURES AND DEWPOINTS
MOSTLY IN THE TEENS TO 20S OVER NC THIS MORNING...WILL SUPPORT A
SIGNIFICANT WINTER STORM **WITH A NARROW P-TYPE (SNOW/RAIN)
TRANSITION ZONE AND DEEP NEAR FREEZING ISOTHERMAL PROFILES
CHARACTERISTIC OF MILLER "A` SFC PATTERNS.** PRECIPITATION
RATES...OCCASIONALLY MODERATE TO HEAVY...WILL ONLY SERVE TO ENHANCE
THE DEEP NEAR FREEZING ISOTHERMAL PROFILES RIGHT ALONG THE SNOW/COLD
RAIN INTERFACE...OWING TO MELTING. A LITTLE MIX OF SLEET AND
FREEZING RAIN ARE HARD TO AVOID IN CENTRAL NC WINTER STORMS...AND IN
MILLER "A" STORMS INCLUDING THIS ONE...SUCH OCCURRENCE IS MOST LIKELY
NEAR THE NARROW TRANSITION SNOW/RAIN ZONE. NO APPRECIABLE ICING IS
ANTICIPATED...HOWEVER...IN PART SINCE SURFACE TEMPERATURES ARE
EXPECTED TO HOLD NEARLY STEADY IN THE 29 TO 33 DEGREE RANGE OVER THE
WARNING AREA...AND 32 TO 34 DEGREES OVER THE ADVISORY AREA WHERE
SUCH ICING OCCURRENCE WOULD BE MOST PROBABLE.
DESPITE SOME MINIMAL OVERALL RISE IN THICKNESS VALUES VERSUS THE
SLIGHTLY COLDER AND DRIER SOLUTIONS OF YESTERDAY...PROJECTED PARTIAL
THICKNESS VALUES OVER MOST OF THE PIEDMONT AND NORTHERN COASTAL
PLAIN REMAIN SQUARELY IN THE RANGE TYPICAL OF SIGNIFICANT SNOWSTORMS
IN CENTRAL NC. WITH A SLIGHTLY MILDER SOLUTION COMES A SLIGHTLY
WETTER ONE...LED BY A BLEND OF THE VERY SIMILAR 00Z ECMWF AND
GFS...SO QPF HAS BEEN RAISED TO AROUND ONE HALF INCH OVER THE NW
PIEDMONT TO AS MUCH AS ONE INCH OVER THE SOUTHERN COASTAL PLAIN.
PARTIAL THICKNESS VALUES HEAVILY WEIGHTED TOWARD THE FAVORED 00Z
ECMWF AND GFS...FAVORS MOSTLY SNOW OVER THE PIEDMONT AND NORTHERN
COASTAL PLAIN...WITH A MIX OF SNOW AND A COLD RAIN (OR FREEZING RAIN
WITH LITTLE ACCRUAL WHERE SFC TEMPERATURES OSCILLATE ABOUT THE
FREEZING MARK) OVER THE ADVISORY AREA.
SNOW RATIOS BETWEEN 00-06Z THU OF 10-14:1 PER WPC WWD SLR GUIDANCE
AND SUPPORTED BY THERMAL PROFILES THAT RANGE FROM DEEP NEAR FREEZING
ISOTHERMAL IN THER NARROW TRANSITION ZONE TO WELL BELOW FREEZING...
EXCEPT RIGHT AT THE SURFACE...ALONG AND NORTH OF THE I-40/I-85
CORRIDOR...ARE EXPECTED TO DECREASE PARTICULARLY NEAR NARROW
TRANSITION ZONE TO CLOSER TO 8-10:1 PER WHAT IS TYPICAL OF EVENTS
CHARACTERIZED BY PARTIAL THICKNESS VALUES IN THE ~1285/~1535 METER
RANGE. SLIGHTLY LOWER RATIOS...CLOSER TO 4-6:1 WITHIN THE SNOW/RAIN
TRANSITION ZONE - OR ROUGHLY ALONG THE BOUNDARY OF WINTER STORM
WARNING AND WINTER WEATHER ADVISORY - WHERE THE MIXING WITH A COLD
RAIN WILL RESULT IN A MORE SLUSHY ACCUMULATION VERSUS POINTS
NORTHWARD.
BASED ON THESE RATIOS...AND THE QPF NOTED ABOVE...WIDESPREAD
SNOWFALL ACCUMULATIONS OF 3 TO 6 INCHES ARE LIKELY OVER THE WARNING
AREA...WITH A STRIPE OF 6 TO 8 INCHES ROUGHLY INVOF OR JUST NORTH OF
THE US HIGHWAY 64 CORRIDOR...WITH LOCALLY HIGHER AMOUNTS FROM THE
TRIANGLE TO ROANOKE RAPIDS AND ROCKY MOUNT. MEANWHILE...LESSER
TOTALS OF 1 TO 3 INCHES ARE EXPECTED OVER THE ADVISORY AREA...WHERE
AGAIN...PARTIAL THICKNESS AND SFC TEMPERATURE VALUES MARGINALLY
ABOVE FREEZING WILL SUPPORT A MIXING WITH OR CHANGEOVER TO A COLD
RAIN BETWEEN MIDNIGHT AND 5 AM. EVEN THERE...HOWEVER...THE NORTHERN
PORTIONS OF THE ADVISORY COUNTIES MAY EXCEED WARNING CRITERIA OF 3
INCHES.
THE APPROACH OF A WEAK CLIPPER LOW AND ATTENDING SHORTWAVE TROUGH
WILL CAUSE THE LINGERING STRATUS LAYER AND ASSOCIATED MOSTLY CLOUDY
SKIES TO PRODUCE OCCASIONAL DRIZZLE OR FREEZING DRIZZLE...AFTER
LINGERING LIGHT SNOW...OWING TO A LOSS OF SATURATION ALOFT/IN THE
ICE NUCLEATION ZONE - BUT WITH MINIMAL ADDITIONAL IMPACT. CHILLY
TEMPERATURES IN THE LOWER TO MIDDLE 30S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
AS OF 1200 PM WEDNESDAY...
SHORTWAVE DISTURBANCES EMBEDDED IN THE CONTINUED SWLY FLOW ALOFT AND
LINGERING LOW-LEVEL MOISTURE OWING TO WHAT WILL LIKELY BE A MOIST
SNOW COVER GROUND(AT LEAST FOR THE NORTHERN TWO-THIRDS OF THE
FORECAST AREA)...WILL RESULT IN RATHER EXTENSIVE CLOUDINESS INTO
SATURDAY. COMBINATION OF THIS CLOUD COVER...SNOW COVER AND THE
ARRIVAL OF ANOTHER FRESH SUPPLY OF ARCTIC AIR INTO THE REGION LATE
THURSDAY NIGHT AND INTO FRIDAY...AS A STRONG +1040MB CANADIAN
SURFACE HIGH BUILDS OVER THE REGION...WILL SUPPORT TEMPERATURES WELL
BELOW NORMAL(15-20 DEGREES FRIDAY AND SATURDAY. DRY WITH HIGHS IN
THE MID 30S NORTH TO POSSIBLY LOWER 40S SOUTH...WITH SATURDAY BEING
THE COLDEST DAY OF THE TWO. -CBL
THE LONG-TERM SATURDAY NIGHT THROUGH WEDNESDAY IS CATEGORIZED BY
SOME UNCERTAINTY IN PRECIPITATION TIMING AND TYPE...WITH AT LEAST
MODEST CONFIDENCE IN MUCH WARMER TEMPERATURES DEVELOPING BY THE END
OF THIS PERIOD THAN WHAT HAS BEEN OCCURRING RECENTLY. DRYING IS
FORECAST FOR SATURDAY NIGHT...WITH A MID-LEVEL SHORTWAVE MOVING INTO
THE CAROLINAS BY SUNDAY NIGHT. AS HEIGHTS ALOFT RISE LATE IN THE
WEEKEND AND EARLY NEXT WEEK...THE 06Z GFS IN PARTICULAR AND POSSIBLY
EVEN THE 12Z GFS SEEMS TO HAVE ISSUES WITH FEEDBACK SUCH THAT THE
ECMWF IS PREFERRED OVERALL. IT SHOULD BE COLD TO START SUNDAY
MORNING AS CLOUDS INCREASE...BUT THE GFS AND ECMWF TREND OF A LATER
ARRIVAL OF MID-LEVEL VORTICITY AND OVERALL MOISTURE INCREASE SHOULD
RESULT IN PRECIPITATION BEING IN THE FORM OF LIQUID BY THE TIME ANY
WOULD ARRIVE LATER IN THE DAY. PARTIAL THICKNESSES AND MODEL
SOUNDINGS CURRENTLY SUPPORT THIS...AND WILL HAVE A CHANCE OF
AFTERNOON RAIN SUNDAY PRIMARILY TOWARD THE YADKIN RIVER FOLLOWED BY
CHANCES OF RAIN OVERNIGHT...WITH SURFACE TEMPERATURES REMAINING
ABOVE FREEZING AND MODEL SOUNDINGS SHOWING WARMING ALOFT AS 1000-
850MB THICKNESSES RISE AROUND 20M DURING THE NIGHT...SUGGESTING THE
POTENTIAL FOR LOW TEMPERATURES EARLY SUNDAY NIGHT FOLLOWED BY STEADY
OR A SLOW RISE IN READINGS LATE.
A BRIEF WARMUP OCCURS MONDAY AHEAD OF A COLD FRONT THAT MOVES
THROUGH CENTRAL NORTH CAROLINA LATER IN THE DAY AND AT NIGHT. STRONG
HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT...AND THE PATTERN
WOULD SUGGEST PRETTY CHILLY TEMPERATURES ONCE AGAIN WITH THE 1000-
850MB THICKNESSES SUGGESTING LOWS A LITTLE BELOW FREEZING. MOS
GUIDANCE LOWS ARE AT LEAST ONE IF NOT MORE CATEGORIES ABOVE THIS...
SO FOR NOW WILL SIMPLY UNDERCUT GUIDANCE WITH OVERNIGHT LOWS AT OR
SLIGHTLY ABOVE FREEZING. CONDITIONS SHOULD DRY BRIEFLY BEHIND THE
FRONT AS HIGH PRESSURE BUILDS IN...THEN UNCERTAINTY INCREASES AS THE
GFS AND THE ECMWF SUGGEST MOISTURE RETURNING TO CENTRAL NORTH
CAROLINA AS THE GULF OPENS BY TUESDAY INTO TUESDAY NIGHT. IF
PRECIPITATION WOULD RETURN TO CENTRAL NORTH CAROLINA QUICKLY ENOUGH
ON TUESDAY...PRECIPITATION TYPE CONCERNS WOULD EXIST DUE TO CHILLY
THICKNESSES TO START THE DAY. BY 00Z WEDNESDAY ON THE 12Z GFS...AND
FOR THE MOST PART ON THE 00Z ECMWF...THICKNESSES ARE WARM ENOUGH FOR
RAIN AND BASED ON THE WARM-AIR ADVECTION AT THE TIME WOULD
ANTICIPATE ANOTHER POTENTIAL NON-DIURNAL TEMPERATURE SCENARIO AS ANY
COLD-AIR DAMMING ERODES. BASED ON THE PATTERN WILL ONLY NOTE A
SLIGHT CHANCE OF RAIN OR SNOW EARLY ON THE SIXTH DAY IN THE WESTERN
PIEDMONT WITH A CHANCE OF JUST ALL RAIN THROUGHOUT CENTRAL NORTH
CAROLINA BY TUESDAY AFTERNOON. 1000-850MB THICKNESSES ON THE 12Z GFS
AND 00Z ECMWF ARE QUITE WARM WEDNESDAY...APPROACHING 1380M ON THE
LATEST GFS AND ONLY SLIGHTLY COOLER ON THE 00Z ECMWF...SUCH THAT...
WITH SHOWERY CONDITIONS IN A MOIST AIR MASS AND A SOUTHWEST FLOW
ALOFT...HIGH TEMPERATURES COULD POSSIBLY REACH THE 60S THROUGHOUT
CENTRAL NORTH CAROLINA WITH SOME TEMPERATURES PUSHING OR EXCEEDING
70F ESPECIALLY OVER PARTS OF THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -DJF
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1255 PM WEDNESDAY...
FOR THE 18Z VALID TAF PERIOD...HIGH CONFIDENCE IN VFR CONDITIONS FOR
THE REST OF THIS AFTERNOON DETERIORATING QUICKLY TO IFR AND SUB-IFR
CONDITIONS THIS EVENING...CONTINUING OVERNIGHT. GUIDANCE SUGGESTS
PRECIPITATION MOVING SOUTHWEST TO NORTHEAST INTO AND ACROSS CENTRAL
NORTH CAROLINA FROM VERY LATE THIS AFTERNOON THROUGH THIS EVENING...
WITH PRECIPITATION ACROSS THE AREA BY 03Z. MODEL SOUNDINGS FROM THE
NAM AND GFS SUGGEST WHATEVER LIQUID PRECIPITATION THERE MAY BE TO
START CHANGING QUICKLY TO SNOW...WITH ENOUGH WARMING ALOFT THAT A
PRECIPITATION TYPE OF SNOW AND SLEET IS QUITE POSSIBLE AT KRDU AND
KRWI. AT KFAY...THE ABOVE FREEZING DEPTH IS A LITTLE HIGHER AND
LIGHT RAIN MAY LINGER A LITTLE LONGER AT THE START BEFORE A
TRANSITION TO SNOW...SLEET...AND FREEZING RAIN...WITH THE NAM MODEL
MOST SUGGESTIVE OF WARMTH ALOFT FOR FREEZING RAIN AND MAINLY FOR A
COUPLE OR THREE HOURS CENTERED AROUND 06Z. DRYING ALOFT VERY LATE
TONIGHT INTO THURSDAY MORNING SUGGEST PRECIPITATION CHANGING TO
FREEZING DRIZZLE OR DRIZZLE...WITH IFR CONDITIONS CONTINUING IN LOW
CLOUDS. VARIABLE WINDS THIS AFTERNOON BECOME NORTH-NORTHEAST AND
NORTHEAST THIS EVENING AS LOW PRESSURE GETS CLOSER AND MOVES
NORTHEAST ALONG THE ATLANTIC COAST.
BEYOND THE 18Z VALID TAF PERIOD...CONFIDENCE DIMINISHES IN
IMPROVEMENT FROM IFR CONDITIONS...WITH AVIATION INTERESTS BEING
PREPARED FOR THE LIKELIHOOD OF SUB-VFR CONDITIONS THROUGH THURSDAY
NIGHT ALBEIT WITH A FEW PERIODS OF VFR CONDITIONS POSSIBLE MAINLY
THURSDAY NIGHT. SUB-VFR CONDITIONS REMAIN POSSIBLE IN LOW CLOUDS
THROUGH FRIDAY WITH A GREATER LIKELIHOOD OF VFR CONDITIONS FOR
FRIDAY NIGHT. VFR CONDITIONS EXPECTED SATURDAY WITH CLOUDS
INCREASING AND LOWERING FOR SUNDAY...THEN SUB-VFR CONDITIONS LIKELY
FOR SUNDAY NIGHT INTO MONDAY ALONG WITH CHANCES FOR PRECIPITATION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST THURSDAY
FOR NCZ078-085-086-088-089.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON EST THURSDAY FOR
NCZ007>011-021>028-038>043-073>077-083-084.
&&
$$
SYNOPSIS...RAH
NEAR TERM...BLAES
SHORT TERM...BLAES/RAH
LONG TERM...CBL/DJF
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1255 PM EST WED FEB 25 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE MOVES QUICKLY FROM THE NORTHERN
GULF OF MEXICO...TO OFF THE CAROLINA COAST OVERNIGHT THROUGH EARLY
THURSDAY. COLD CANADIAN HIGH PRESSURE THEN BUILDS INTO THE REGION
FRIDAY AND INTO THE WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 1105 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE THROUGH NOON TODAY...
WILL CANCEL THE WINTER WEATHER ADVISORY SHORTLY.
MORNING UPPER AIR ANALYSIS SHOWS THE SHEARING SHORT WAVE
TROUGH OVER TEXAS THIS MORNING WITH SHORT WAVE RIDGING OUT AHEAD OF
IT ACROSS THE SOUTHEAST. HIGH CLOUDS HAVE BEEN ADVANCING NORTHEAST
AHEAD OF THE SYSTEM AND MOST OF CENTRAL NC IS ALREADY UNDER AT LEAST
A THIN VEIL OF CIRRUS. REGIONAL RADAR IMAGERY SHOWS PRECIPITATION
EXPANDING ACROSS THE DEEP SOUTH WITH MEASURABLE PRECIP NOW REPORTED
ACROSS CENTRAL ALABAMA. NO PRECIPITATION IS EXPECTED IN CENTRAL NC
DURING THE TODAY PERIOD BUT TODAYS WEATHER COULD STILL PLAY A ROLE IN
THE IMPACT OF TONIGHTS WINTER STORM. THE TEMPERATURES FORECAST FOR
TODAY IS PROBLEMATIC AS YESTERDAYS SNOWFALL WILL DAMPEN THE
TEMPERATURE RECOVERY THIS AFTERNOON AND ENERGY IS DIVERTED INTO
MELTING AND EVAPORATING SNOW AND MELT WATER. EVEN SO...SOME
GUIDANCE INCLUDING THE HRRR SUGGEST HIGHS IN THE MID 40S TO AROUND
50. NOT READY TO JUMP THAT HIGH BUT CURRENT TEMP AT OUR OFFICE IS 37
AT 1045 AND HAVE MADE A SLIGHT UPWARD ADJUSTMENT IN TEMPERATURES FOR
TODAY. THIS UPWARD TREND IN BOUNDARY LAYER TEMPERATURES WOULD
DELAY THE CHANGEOVER FROM RAIN OR MIXED RAIN AND SNOW THIS EVENING
TO SNOW AND POTENTIALLY LIMIT ACCUMULATIONS A BIT...PRIMARILY
ACROSS THE FAR SOUTHERN TIER IN THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -BLAES
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS OF 1100 AM WEDNESDAY...
*** QUICK 1100 AM UPDATE. QUICK LOOK AT 12Z GUIDANCE NOTES NO
IMMEDIATE OR SIGNIFICANT FORECAST ADJUSTMENTS ARE NEEDED BUT NAM
CONTINUES TO TREND NORTH A BIT AND WITH THE GFS SHOWING A SLIGHT
NORTHWARD ADJUSTMENT.
...WINTER STORM WARNING HAS BEEN ISSUED FOR TONIGHT AND THURSDAY FOR
ALL THE PIEDMONT...NORTHERN/CENTRAL COASTAL PLAIN AND SANDHILLS...
...WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR TONIGHT AND THURSDAY
FOR THE SOUTHERN COASTAL PLAIN...
THERE HAS BEEN A CONTINUED SLIGHT NORTHWARD SHIFT IN GUIDANCE SINCE
YESTERDAY...WHICH EQUATES TO A WETTER AND MARGINALLY WARMER SOLUTION
FOR CENTRAL NC...THOUGH THE OVERALL PATTERN REMAINS UNCHANGED WITH
THE DEAMPLIFICATION/ENE SHEARING OF A SHORTWAVE TROUGH FROM NEAR THE
RIO GRANDE THIS MORNING TO THE MIDDLE ATLANTIC COAST BY THU MORNING.
THE ASSOCIATED FORCING FOR ASCENT ATOP A PAIR OF CLOSELY-SPACED AND
STRONG FRONTAL ZONES DRAPED ACROSS THE NORTHERN GOM TO A SFC LOW
ABOUT MIDWAY BETWEEN CAPE HATTERAS AND BERMUDA...WILL RESULT IN THE
CONTINUED DEEPENING OF A SFC LOW OVER THE NW GOM THIS MORNING.
GUIDANCE IS THEN FAIRLY TIGHTLY CLUSTERED WITH THE TRACK OF A MILLER
"A" SFC LOW ACROSS THE NORTHERN FL PENINSULA THIS EVENING AND
ROUGHLY ALONG THE GULF STREAM TO JUST EAST OF CAPE HATTERAS BY 12Z
THU.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS...THE LACK OF A PARENT
COLD HIGH IS ADMITTEDLY SOMEWHAT CONCERNING. AN ARCTIC SFC HIGH AT
1045 MB WILL BE CENTERED OVER SOUTHERN ALBERTA/SASKATCHEWAN AND WILL
CONSEQUENTLY HAVE LITTLE INFLUENCE AT OUR LATITUDE DURING THE HEIGHT
OF THE STORM TONIGHT. HOWEVER...A VERY FAVORABLE MILLER "A" CYCLONE
TRACK ALONG AND JUST OFFSHORE THE SE COAST...IN CONJUNCTION WITH A
PRECEDING ARCTIC HIGH THAT APPEARS TO BE JUST COLD ENOUGH DESPITE
BEING IN A DRAMATICALLY WEAKENED STATE FROM A COUPLE OF DAYS
AGO...BUT IS STILL CHARACTERIZED BY SFC TEMPERATURES AND DEWPOINTS
MOSTLY IN THE TEENS TO 20S OVER NC THIS MORNING...WILL SUPPORT A
SIGNIFICANT WINTER STORM **WITH A NARROW P-TYPE (SNOW/RAIN)
TRANSITION ZONE AND DEEP NEAR FREEZING ISOTHERMAL PROFILES
CHARACTERISTIC OF MILLER "A` SFC PATTERNS.** PRECIPITATION
RATES...OCCASIONALLY MODERATE TO HEAVY...WILL ONLY SERVE TO ENHANCE
THE DEEP NEAR FREEZING ISOTHERMAL PROFILES RIGHT ALONG THE SNOW/COLD
RAIN INTERFACE...OWING TO MELTING. A LITTLE MIX OF SLEET AND
FREEZING RAIN ARE HARD TO AVOID IN CENTRAL NC WINTER STORMS...AND IN
MILLER "A" STORMS INCLUDING THIS ONE...SUCH OCCURRENCE IS MOST LIKELY
NEAR THE NARROW TRANSITION SNOW/RAIN ZONE. NO APPRECIABLE ICING IS
ANTICIPATED...HOWEVER...IN PART SINCE SURFACE TEMPERATURES ARE
EXPECTED TO HOLD NEARLY STEADY IN THE 29 TO 33 DEGREE RANGE OVER THE
WARNING AREA...AND 32 TO 34 DEGREES OVER THE ADVISORY AREA WHERE
SUCH ICING OCCURRENCE WOULD BE MOST PROBABLE.
DESPITE SOME MINIMAL OVERALL RISE IN THICKNESS VALUES VERSUS THE
SLIGHTLY COLDER AND DRIER SOLUTIONS OF YESTERDAY...PROJECTED PARTIAL
THICKNESS VALUES OVER MOST OF THE PIEDMONT AND NORTHERN COASTAL
PLAIN REMAIN SQUARELY IN THE RANGE TYPICAL OF SIGNIFICANT SNOWSTORMS
IN CENTRAL NC. WITH A SLIGHTLY MILDER SOLUTION COMES A SLIGHTLY
WETTER ONE...LED BY A BLEND OF THE VERY SIMILAR 00Z ECMWF AND
GFS...SO QPF HAS BEEN RAISED TO AROUND ONE HALF INCH OVER THE NW
PIEDMONT TO AS MUCH AS ONE INCH OVER THE SOUTHERN COASTAL PLAIN.
PARTIAL THICKNESS VALUES HEAVILY WEIGHTED TOWARD THE FAVORED 00Z
ECMWF AND GFS...FAVORS MOSTLY SNOW OVER THE PIEDMONT AND NORTHERN
COASTAL PLAIN...WITH A MIX OF SNOW AND A COLD RAIN (OR FREEZING RAIN
WITH LITTLE ACCRUAL WHERE SFC TEMPERATURES OSCILLATE ABOUT THE
FREEZING MARK) OVER THE ADVISORY AREA.
SNOW RATIOS BETWEEN 00-06Z THU OF 10-14:1 PER WPC WWD SLR GUIDANCE
AND SUPPORTED BY THERMAL PROFILES THAT RANGE FROM DEEP NEAR FREEZING
ISOTHERMAL IN THER NARROW TRANSITION ZONE TO WELL BELOW FREEZING...
EXCEPT RIGHT AT THE SURFACE...ALONG AND NORTH OF THE I-40/I-85
CORRIDOR...ARE EXPECTED TO DECREASE PARTICULARLY NEAR NARROW
TRANSITION ZONE TO CLOSER TO 8-10:1 PER WHAT IS TYPICAL OF EVENTS
CHARACTERIZED BY PARTIAL THICKNESS VALUES IN THE ~1285/~1535 METER
RANGE. SLIGHTLY LOWER RATIOS...CLOSER TO 4-6:1 WITHIN THE SNOW/RAIN
TRANSITION ZONE - OR ROUGHLY ALONG THE BOUNDARY OF WINTER STORM
WARNING AND WINTER WEATHER ADVISORY - WHERE THE MIXING WITH A COLD
RAIN WILL RESULT IN A MORE SLUSHY ACCUMULATION VERSUS POINTS
NORTHWARD.
BASED ON THESE RATIOS...AND THE QPF NOTED ABOVE...WIDESPREAD
SNOWFALL ACCUMULATIONS OF 3 TO 6 INCHES ARE LIKELY OVER THE WARNING
AREA...WITH A STRIPE OF 6 TO 8 INCHES ROUGHLY INVOF OR JUST NORTH OF
THE US HIGHWAY 64 CORRIDOR...WITH LOCALLY HIGHER AMOUNTS FROM THE
TRIANGLE TO ROANOKE RAPIDS AND ROCKY MOUNT. MEANWHILE...LESSER
TOTALS OF 1 TO 3 INCHES ARE EXPECTED OVER THE ADVISORY AREA...WHERE
AGAIN...PARTIAL THICKNESS AND SFC TEMPERATURE VALUES MARGINALLY
ABOVE FREEZING WILL SUPPORT A MIXING WITH OR CHANGEOVER TO A COLD
RAIN BETWEEN MIDNIGHT AND 5 AM. EVEN THERE...HOWEVER...THE NORTHERN
PORTIONS OF THE ADVISORY COUNTIES MAY EXCEED WARNING CRITERIA OF 3
INCHES.
THE APPROACH OF A WEAK CLIPPER LOW AND ATTENDING SHORTWAVE TROUGH
WILL CAUSE THE LINGERING STRATUS LAYER AND ASSOCIATED MOSTLY CLOUDY
SKIES TO PRODUCE OCCASIONAL DRIZZLE OR FREEZING DRIZZLE...AFTER
LINGERING LIGHT SNOW...OWING TO A LOSS OF SATURATION ALOFT/IN THE
ICE NUCLEATION ZONE - BUT WITH MINIMAL ADDITIONAL IMPACT. CHILLY
TEMPERATURES IN THE LOWER TO MIDDLE 30S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
AS OF 1200 PM WEDNESDAY...
SHORTWAVE DISTURBANCES EMBEDDED IN THE CONTINUED SWLY FLOW ALOFT AND
LINGERING LOW-LEVEL MOISTURE OWING TO WHAT WILL LIKELY BE A MOIST
SNOW COVER GROUND(AT LEAST FOR THE NORTHERN TWO-THIRDS OF THE
FORECAST AREA)...WILL RESULT IN RATHER EXTENSIVE CLOUDINESS INTO
SATURDAY. COMBINATION OF THIS CLOUD COVER...SNOW COVER AND THE
ARRIVAL OF ANOTHER FRESH SUPPLY OF ARCTIC AIR INTO THE REGION LATE
THURSDAY NIGHT AND INTO FRIDAY...AS A STRONG +1040MB CANADIAN
SURFACE HIGH BUILDS OVER THE REGION...WILL SUPPORT TEMPERATURES WELL
BELOW NORMAL(15-20 DEGREES FRIDAY AND SATURDAY. DRY WITH HIGHS IN
THE MID 30S NORTH TO POSSIBLY LOWER 40S SOUTH...WITH SATURDAY BEING
THE COLDEST DAY OF THE TWO. -CBL
THE LONG-TERM SATURDAY NIGHT THROUGH WEDNESDAY IS CATEGORIZED BY
SOME UNCERTAINTY IN PRECIPITATION TIMING AND TYPE...WITH AT LEAST
MODEST CONFIDENCE IN MUCH WARMER TEMPERATURES DEVELOPING BY THE END
OF THIS PERIOD THAN WHAT HAS BEEN OCCURRING RECENTLY. DRYING IS
FORECAST FOR SATURDAY NIGHT...WITH A MID-LEVEL SHORTWAVE MOVING INTO
THE CAROLINAS BY SUNDAY NIGHT. AS HEIGHTS ALOFT RISE LATE IN THE
WEEKEND AND EARLY NEXT WEEK...THE 06Z GFS IN PARTICULAR AND POSSIBLY
EVEN THE 12Z GFS SEEMS TO HAVE ISSUES WITH FEEDBACK SUCH THAT THE
ECMWF IS PREFERRED OVERALL. IT SHOULD BE COLD TO START SUNDAY
MORNING AS CLOUDS INCREASE...BUT THE GFS AND ECMWF TREND OF A LATER
ARRIVAL OF MID-LEVEL VORTICITY AND OVERALL MOISTURE INCREASE SHOULD
RESULT IN PRECIPITATION BEING IN THE FORM OF LIQUID BY THE TIME ANY
WOULD ARRIVE LATER IN THE DAY. PARTIAL THICKNESSES AND MODEL
SOUNDINGS CURRENTLY SUPPORT THIS...AND WILL HAVE A CHANCE OF
AFTERNOON RAIN SUNDAY PRIMARILY TOWARD THE YADKIN RIVER FOLLOWED BY
CHANCES OF RAIN OVERNIGHT...WITH SURFACE TEMPERATURES REMAINING
ABOVE FREEZING AND MODEL SOUNDINGS SHOWING WARMING ALOFT AS 1000-
850MB THICKNESSES RISE AROUND 20M DURING THE NIGHT...SUGGESTING THE
POTENTIAL FOR LOW TEMPERATURES EARLY SUNDAY NIGHT FOLLOWED BY STEADY
OR A SLOW RISE IN READINGS LATE.
A BRIEF WARMUP OCCURS MONDAY AHEAD OF A COLD FRONT THAT MOVES
THROUGH CENTRAL NORTH CAROLINA LATER IN THE DAY AND AT NIGHT. STRONG
HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT...AND THE PATTERN
WOULD SUGGEST PRETTY CHILLY TEMPERATURES ONCE AGAIN WITH THE 1000-
850MB THICKNESSES SUGGESTING LOWS A LITTLE BELOW FREEZING. MOS
GUIDANCE LOWS ARE AT LEAST ONE IF NOT MORE CATEGORIES ABOVE THIS...
SO FOR NOW WILL SIMPLY UNDERCUT GUIDANCE WITH OVERNIGHT LOWS AT OR
SLIGHTLY ABOVE FREEZING. CONDITIONS SHOULD DRY BRIEFLY BEHIND THE
FRONT AS HIGH PRESSURE BUILDS IN...THEN UNCERTAINTY INCREASES AS THE
GFS AND THE ECMWF SUGGEST MOISTURE RETURNING TO CENTRAL NORTH
CAROLINA AS THE GULF OPENS BY TUESDAY INTO TUESDAY NIGHT. IF
PRECIPITATION WOULD RETURN TO CENTRAL NORTH CAROLINA QUICKLY ENOUGH
ON TUESDAY...PRECIPITATION TYPE CONCERNS WOULD EXIST DUE TO CHILLY
THICKNESSES TO START THE DAY. BY 00Z WEDNESDAY ON THE 12Z GFS...AND
FOR THE MOST PART ON THE 00Z ECMWF...THICKNESSES ARE WARM ENOUGH FOR
RAIN AND BASED ON THE WARM-AIR ADVECTION AT THE TIME WOULD
ANTICIPATE ANOTHER POTENTIAL NON-DIURNAL TEMPERATURE SCENARIO AS ANY
COLD-AIR DAMMING ERODES. BASED ON THE PATTERN WILL ONLY NOTE A
SLIGHT CHANCE OF RAIN OR SNOW EARLY ON THE SIXTH DAY IN THE WESTERN
PIEDMONT WITH A CHANCE OF JUST ALL RAIN THROUGHOUT CENTRAL NORTH
CAROLINA BY TUESDAY AFTERNOON. 1000-850MB THICKNESSES ON THE 12Z GFS
AND 00Z ECMWF ARE QUITE WARM WEDNESDAY...APPROACHING 1380M ON THE
LATEST GFS AND ONLY SLIGHTLY COOLER ON THE 00Z ECMWF...SUCH THAT...
WITH SHOWERY CONDITIONS IN A MOIST AIR MASS AND A SOUTHWEST FLOW
ALOFT...HIGH TEMPERATURES COULD POSSIBLY REACH THE 60S THROUGHOUT
CENTRAL NORTH CAROLINA WITH SOME TEMPERATURES PUSHING OR EXCEEDING
70F ESPECIALLY OVER PARTS OF THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -DJF
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1255 PM WEDNESDAY...
FOR THE 18Z VALID TAF PERIOD...HIGH CONFIDENCE IN VFR CONDITIONS FOR
THE REST OF THIS AFTERNOON DETERIORATING QUICKLY TO IFR AND SUB-IFR
CONDITIONS THIS EVENING...CONTINUING OVERNIGHT. GUIDANCE SUGGESTS
PRECIPITATION MOVING SOUTHWEST TO NORTHEAST INTO AND ACROSS CENTRAL
NORTH CAROLINA FROM VERY LATE THIS AFTERNOON THROUGH THIS EVENING...
WITH PRECIPITATION ACROSS THE AREA BY 03Z. MODEL SOUNDINGS FROM THE
NAM AND GFS SUGGEST WHATEVER LIQUID PRECIPITATION THERE MAY BE TO
START CHANGING QUICKLY TO SNOW...WITH ENOUGH WARMING ALOFT THAT A
PRECIPITATION TYPE OF SNOW AND SLEET IS QUITE POSSIBLE AT KRDU AND
KRWI. AT KFAY...THE ABOVE FREEZING DEPTH IS A LITTLE HIGHER AND
LIGHT RAIN MAY LINGER A LITTLE LONGER AT THE START BEFORE A
TRANSITION TO SNOW...SLEET...AND FREEZING RAIN...WITH THE NAM MODEL
MOST SUGGESTIVE OF WARMTH ALOFT FOR FREEZING RAIN AND MAINLY FOR A
COUPLE OR THREE HOURS CENTERED AROUND 06Z. DRYING ALOFT VERY LATE
TONIGHT INTO THURSDAY MORNING SUGGEST PRECIPITATION CHANGING TO
FREEZING DRIZZLE OR DRIZZLE...WITH IFR CONDITIONS CONTINUING IN LOW
CLOUDS. VARIABLE WINDS THIS AFTERNOON BECOME NORTH-NORTHEAST AND
NORTHEAST THIS EVENING AS LOW PRESSURE GETS CLOSER AND MOVES
NORTHEAST ALONG THE ATLANTIC COAST.
BEYOND THE 18Z VALID TAF PERIOD...CONFIDENCE DIMINISHES IN
IMPROVEMENT FROM IFR CONDITIONS...WITH AVIATION INTERESTS BEING
PREPARED FOR THE LIKELIHOOD OF SUB-VFR CONDITIONS THROUGH THURSDAY
NIGHT ALBEIT WITH A FEW PERIODS OF VFR CONDITIONS POSSIBLE MAINLY
THURSDAY NIGHT. SUB-VFR CONDITIONS REMAIN POSSIBLE IN LOW CLOUDS
THROUGH FRIDAY WITH A GREATER LIKELIHOOD OF VFR CONDITIONS FOR
FRIDAY NIGHT. VFR CONDITIONS EXPECTED SATURDAY WITH CLOUDS
INCREASING AND LOWERING FOR SUNDAY...THEN SUB-VFR CONDITIONS LIKELY
FOR SUNDAY NIGHT INTO MONDAY ALONG WITH CHANCES FOR PRECIPITATION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON WEDNESDAY FOR NCZ007>011-024>028-
040>043-076>078-085-086-088-089.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST THURSDAY
FOR NCZ078-085-086-088-089.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON EST THURSDAY FOR
NCZ007>011-021>028-038>043-073>077-083-084.
&&
$$
SYNOPSIS...RAH
NEAR TERM...BLAES
SHORT TERM...BLAES/RAH
LONG TERM...CBL/DJF
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1200 PM EST WED FEB 25 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE WILL FORM OVER THE NORTHERN GULF
OF MEXICO TODAY AND WILL THEN TRACK QUICKLY NORTHEAST...OFF THE
CAROLINA COAST OVERNIGHT THROUGH EARLY THURSDAY. COLD CANADIAN
HIGH PRESSURE WILL THEN BUILD INTO THE REGION FRIDAY AND INTO THE
WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 1105 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE THROUGH NOON TODAY...
WILL CANCEL THE WINTER WEATHER ADVISORY SHORTLY.
MORNING UPPER AIR ANALYSIS SHOWS THE SHEARING SHORT WAVE
TROUGH OVER TEXAS THIS MORNING WITH SHORT WAVE RIDGING OUT AHEAD OF
IT ACROSS THE SOUTHEAST. HIGH CLOUDS HAVE BEEN ADVANCING NORTHEAST
AHEAD OF THE SYSTEM AND MOST OF CENTRAL NC IS ALREADY UNDER AT LEAST
A THIN VEIL OF CIRRUS. REGIONAL RADAR IMAGERY SHOWS PRECIPITATION
EXPANDING ACROSS THE DEEP SOUTH WITH MEASURABLE PRECIP NOW REPORTED
ACROSS CENTRAL ALABAMA. NO PRECIPITATION IS EXPECTED IN CENTRAL NC
DURING THE TODAY PERIOD BUT TODAYS WEATHER COULD STILL PLAY A ROLE IN
THE IMPACT OF TONIGHTS WINTER STORM. THE TEMPERATURES FORECAST FOR
TODAY IS PROBLEMATIC AS YESTERDAYS SNOWFALL WILL DAMPEN THE
TEMPERATURE RECOVERY THIS AFTERNOON AND ENERGY IS DIVERTED INTO
MELTING AND EVAPORATING SNOW AND MELT WATER. EVEN SO...SOME
GUIDANCE INCLUDING THE HRRR SUGGEST HIGHS IN THE MID 40S TO AROUND
50. NOT READY TO JUMP THAT HIGH BUT CURRENT TEMP AT OUR OFFICE IS 37
AT 1045 AND HAVE MADE A SLIGHT UPWARD ADJUSTMENT IN TEMPERATURES FOR
TODAY. THIS UPWARD TREND IN BOUNDARY LAYER TEMPERATURES WOULD
DELAY THE CHANGEOVER FROM RAIN OR MIXED RAIN AND SNOW THIS EVENING
TO SNOW AND POTENTIALLY LIMIT ACCUMULATIONS A BIT...PRIMARILY
ACROSS THE FAR SOUTHERN TIER IN THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -BLAES
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS OF 1100 AM WEDNESDAY...
*** QUICK 1100 AM UPDATE. QUICK LOOK AT 12Z GUIDANCE NOTES NO
IMMEDIATE OR SIGNIFICANT FORECAST ADJUSTMENTS ARE NEEDED BUT NAM
CONTINUES TO TREND NORTH A BIT AND WITH THE GFS SHOWING A SLIGHT
NORTHWARD ADJUSTMENT.
...WINTER STORM WARNING HAS BEEN ISSUED FOR TONIGHT AND THURSDAY FOR
ALL THE PIEDMONT...NORTHERN/CENTRAL COASTAL PLAIN AND SANDHILLS...
...WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR TONIGHT AND THURSDAY
FOR THE SOUTHERN COASTAL PLAIN...
THERE HAS BEEN A CONTINUED SLIGHT NORTHWARD SHIFT IN GUIDANCE SINCE
YESTERDAY...WHICH EQUATES TO A WETTER AND MARGINALLY WARMER SOLUTION
FOR CENTRAL NC...THOUGH THE OVERALL PATTERN REMAINS UNCHANGED WITH
THE DEAMPLIFICATION/ENE SHEARING OF A SHORTWAVE TROUGH FROM NEAR THE
RIO GRANDE THIS MORNING TO THE MIDDLE ATLANTIC COAST BY THU MORNING.
THE ASSOCIATED FORCING FOR ASCENT ATOP A PAIR OF CLOSELY-SPACED AND
STRONG FRONTAL ZONES DRAPED ACROSS THE NORTHERN GOM TO A SFC LOW
ABOUT MIDWAY BETWEEN CAPE HATTERAS AND BERMUDA...WILL RESULT IN THE
CONTINUED DEEPENING OF A SFC LOW OVER THE NW GOM THIS MORNING.
GUIDANCE IS THEN FAIRLY TIGHTLY CLUSTERED WITH THE TRACK OF A MILLER
"A" SFC LOW ACROSS THE NORTHERN FL PENINSULA THIS EVENING AND
ROUGHLY ALONG THE GULF STREAM TO JUST EAST OF CAPE HATTERAS BY 12Z
THU.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS...THE LACK OF A PARENT
COLD HIGH IS ADMITTEDLY SOMEWHAT CONCERNING. AN ARCTIC SFC HIGH AT
1045 MB WILL BE CENTERED OVER SOUTHERN ALBERTA/SASKATCHEWAN AND WILL
CONSEQUENTLY HAVE LITTLE INFLUENCE AT OUR LATITUDE DURING THE HEIGHT
OF THE STORM TONIGHT. HOWEVER...A VERY FAVORABLE MILLER "A" CYCLONE
TRACK ALONG AND JUST OFFSHORE THE SE COAST...IN CONJUNCTION WITH A
PRECEDING ARCTIC HIGH THAT APPEARS TO BE JUST COLD ENOUGH DESPITE
BEING IN A DRAMATICALLY WEAKENED STATE FROM A COUPLE OF DAYS
AGO...BUT IS STILL CHARACTERIZED BY SFC TEMPERATURES AND DEWPOINTS
MOSTLY IN THE TEENS TO 20S OVER NC THIS MORNING...WILL SUPPORT A
SIGNIFICANT WINTER STORM **WITH A NARROW P-TYPE (SNOW/RAIN)
TRANSITION ZONE AND DEEP NEAR FREEZING ISOTHERMAL PROFILES
CHARACTERISTIC OF MILLER "A` SFC PATTERNS.** PRECIPITATION
RATES...OCCASIONALLY MODERATE TO HEAVY...WILL ONLY SERVE TO ENHANCE
THE DEEP NEAR FREEZING ISOTHERMAL PROFILES RIGHT ALONG THE SNOW/COLD
RAIN INTERFACE...OWING TO MELTING. A LITTLE MIX OF SLEET AND
FREEZING RAIN ARE HARD TO AVOID IN CENTRAL NC WINTER STORMS...AND IN
MILLER "A" STORMS INCLUDING THIS ONE...SUCH OCCURRENCE IS MOST LIKELY
NEAR THE NARROW TRANSITION SNOW/RAIN ZONE. NO APPRECIABLE ICING IS
ANTICIPATED...HOWEVER...IN PART SINCE SURFACE TEMPERATURES ARE
EXPECTED TO HOLD NEARLY STEADY IN THE 29 TO 33 DEGREE RANGE OVER THE
WARNING AREA...AND 32 TO 34 DEGREES OVER THE ADVISORY AREA WHERE
SUCH ICING OCCURRENCE WOULD BE MOST PROBABLE.
DESPITE SOME MINIMAL OVERALL RISE IN THICKNESS VALUES VERSUS THE
SLIGHTLY COLDER AND DRIER SOLUTIONS OF YESTERDAY...PROJECTED PARTIAL
THICKNESS VALUES OVER MOST OF THE PIEDMONT AND NORTHERN COASTAL
PLAIN REMAIN SQUARELY IN THE RANGE TYPICAL OF SIGNIFICANT SNOWSTORMS
IN CENTRAL NC. WITH A SLIGHTLY MILDER SOLUTION COMES A SLIGHTLY
WETTER ONE...LED BY A BLEND OF THE VERY SIMILAR 00Z ECMWF AND
GFS...SO QPF HAS BEEN RAISED TO AROUND ONE HALF INCH OVER THE NW
PIEDMONT TO AS MUCH AS ONE INCH OVER THE SOUTHERN COASTAL PLAIN.
PARTIAL THICKNESS VALUES HEAVILY WEIGHTED TOWARD THE FAVORED 00Z
ECMWF AND GFS...FAVORS MOSTLY SNOW OVER THE PIEDMONT AND NORTHERN
COASTAL PLAIN...WITH A MIX OF SNOW AND A COLD RAIN (OR FREEZING RAIN
WITH LITTLE ACCRUAL WHERE SFC TEMPERATURES OSCILLATE ABOUT THE
FREEZING MARK) OVER THE ADVISORY AREA.
SNOW RATIOS BETWEEN 00-06Z THU OF 10-14:1 PER WPC WWD SLR GUIDANCE
AND SUPPORTED BY THERMAL PROFILES THAT RANGE FROM DEEP NEAR FREEZING
ISOTHERMAL IN THER NARROW TRANSITION ZONE TO WELL BELOW FREEZING...
EXCEPT RIGHT AT THE SURFACE...ALONG AND NORTH OF THE I-40/I-85
CORRIDOR...ARE EXPECTED TO DECREASE PARTICULARLY NEAR NARROW
TRANSITION ZONE TO CLOSER TO 8-10:1 PER WHAT IS TYPICAL OF EVENTS
CHARACTERIZED BY PARTIAL THICKNESS VALUES IN THE ~1285/~1535 METER
RANGE. SLIGHTLY LOWER RATIOS...CLOSER TO 4-6:1 WITHIN THE SNOW/RAIN
TRANSITION ZONE - OR ROUGHLY ALONG THE BOUNDARY OF WINTER STORM
WARNING AND WINTER WEATHER ADVISORY - WHERE THE MIXING WITH A COLD
RAIN WILL RESULT IN A MORE SLUSHY ACCUMULATION VERSUS POINTS
NORTHWARD.
BASED ON THESE RATIOS...AND THE QPF NOTED ABOVE...WIDESPREAD
SNOWFALL ACCUMULATIONS OF 3 TO 6 INCHES ARE LIKELY OVER THE WARNING
AREA...WITH A STRIPE OF 6 TO 8 INCHES ROUGHLY INVOF OR JUST NORTH OF
THE US HIGHWAY 64 CORRIDOR...WITH LOCALLY HIGHER AMOUNTS FROM THE
TRIANGLE TO ROANOKE RAPIDS AND ROCKY MOUNT. MEANWHILE...LESSER
TOTALS OF 1 TO 3 INCHES ARE EXPECTED OVER THE ADVISORY AREA...WHERE
AGAIN...PARTIAL THICKNESS AND SFC TEMPERATURE VALUES MARGINALLY
ABOVE FREEZING WILL SUPPORT A MIXING WITH OR CHANGEOVER TO A COLD
RAIN BETWEEN MIDNIGHT AND 5 AM. EVEN THERE...HOWEVER...THE NORTHERN
PORTIONS OF THE ADVISORY COUNTIES MAY EXCEED WARNING CRITERIA OF 3
INCHES.
THE APPROACH OF A WEAK CLIPPER LOW AND ATTENDING SHORTWAVE TROUGH
WILL CAUSE THE LINGERING STRATUS LAYER AND ASSOCIATED MOSTLY CLOUDY
SKIES TO PRODUCE OCCASIONAL DRIZZLE OR FREEZING DRIZZLE...AFTER
LINGERING LIGHT SNOW...OWING TO A LOSS OF SATURATION ALOFT/IN THE
ICE NUCLEATION ZONE - BUT WITH MINIMAL ADDITIONAL IMPACT. CHILLY
TEMPERATURES IN THE LOWER TO MIDDLE 30S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
AS OF 1200 PM WEDNESDAY...
SHORTWAVE DISTURBANCES EMBEDDED IN THE CONTINUED SWLY FLOW ALOFT AND
LINGERING LOW-LEVEL MOISTURE OWING TO WHAT WILL LIKELY BE A MOIST
SNOW COVER GROUND(AT LEAST FOR THE NORTHERN TWO-THIRDS OF THE
FORECAST AREA)...WILL RESULT IN RATHER EXTENSIVE CLOUDINESS INTO
SATURDAY. COMBINATION OF THIS CLOUD COVER...SNOW COVER AND THE
ARRIVAL OF ANOTHER FRESH SUPPLY OF ARCTIC AIR INTO THE REGION LATE
THURSDAY NIGHT AND INTO FRIDAY...AS A STRONG +1040MB CANADIAN
SURFACE HIGH BUILDS OVER THE REGION...WILL SUPPORT TEMPERATURES WELL
BELOW NORMAL(15-20 DEGREES FRIDAY AND SATURDAY. DRY WITH HIGHS IN
THE MID 30S NORTH TO POSSIBLY LOWER 40S SOUTH...WITH SATURDAY BEING
THE COLDEST DAY OF THE TWO. -CBL
THE LONG-TERM SATURDAY NIGHT THROUGH WEDNESDAY IS CATEGORIZED BY
SOME UNCERTAINTY IN PRECIPITATION TIMING AND TYPE...WITH AT LEAST
MODEST CONFIDENCE IN MUCH WARMER TEMPERATURES DEVELOPING BY THE END
OF THIS PERIOD THAN WHAT HAS BEEN OCCURRING RECENTLY. DRYING IS
FORECAST FOR SATURDAY NIGHT...WITH A MID-LEVEL SHORTWAVE MOVING INTO
THE CAROLINAS BY SUNDAY NIGHT. AS HEIGHTS ALOFT RISE LATE IN THE
WEEKEND AND EARLY NEXT WEEK...THE 06Z GFS IN PARTICULAR AND POSSIBLY
EVEN THE 12Z GFS SEEMS TO HAVE ISSUES WITH FEEDBACK SUCH THAT THE
ECMWF IS PREFERRED OVERALL. IT SHOULD BE COLD TO START SUNDAY
MORNING AS CLOUDS INCREASE...BUT THE GFS AND ECMWF TREND OF A LATER
ARRIVAL OF MID-LEVEL VORTICITY AND OVERALL MOISTURE INCREASE SHOULD
RESULT IN PRECIPITATION BEING IN THE FORM OF LIQUID BY THE TIME ANY
WOULD ARRIVE LATER IN THE DAY. PARTIAL THICKNESSES AND MODEL
SOUNDINGS CURRENTLY SUPPORT THIS...AND WILL HAVE A CHANCE OF
AFTERNOON RAIN SUNDAY PRIMARILY TOWARD THE YADKIN RIVER FOLLOWED BY
CHANCES OF RAIN OVERNIGHT...WITH SURFACE TEMPERATURES REMAINING
ABOVE FREEZING AND MODEL SOUNDINGS SHOWING WARMING ALOFT AS 1000-
850MB THICKNESSES RISE AROUND 20M DURING THE NIGHT...SUGGESTING THE
POTENTIAL FOR LOW TEMPERATURES EARLY SUNDAY NIGHT FOLLOWED BY STEADY
OR A SLOW RISE IN READINGS LATE.
A BRIEF WARMUP OCCURS MONDAY AHEAD OF A COLD FRONT THAT MOVES
THROUGH CENTRAL NORTH CAROLINA LATER IN THE DAY AND AT NIGHT. STRONG
HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT...AND THE PATTERN
WOULD SUGGEST PRETTY CHILLY TEMPERATURES ONCE AGAIN WITH THE 1000-
850MB THICKNESSES SUGGESTING LOWS A LITTLE BELOW FREEZING. MOS
GUIDANCE LOWS ARE AT LEAST ONE IF NOT MORE CATEGORIES ABOVE THIS...
SO FOR NOW WILL SIMPLY UNDERCUT GUIDANCE WITH OVERNIGHT LOWS AT OR
SLIGHTLY ABOVE FREEZING. CONDITIONS SHOULD DRY BRIEFLY BEHIND THE
FRONT AS HIGH PRESSURE BUILDS IN...THEN UNCERTAINTY INCREASES AS THE
GFS AND THE ECMWF SUGGEST MOISTURE RETURNING TO CENTRAL NORTH
CAROLINA AS THE GULF OPENS BY TUESDAY INTO TUESDAY NIGHT. IF
PRECIPITATION WOULD RETURN TO CENTRAL NORTH CAROLINA QUICKLY ENOUGH
ON TUESDAY...PRECIPITATION TYPE CONCERNS WOULD EXIST DUE TO CHILLY
THICKNESSES TO START THE DAY. BY 00Z WEDNESDAY ON THE 12Z GFS...AND
FOR THE MOST PART ON THE 00Z ECMWF...THICKNESSES ARE WARM ENOUGH FOR
RAIN AND BASED ON THE WARM-AIR ADVECTION AT THE TIME WOULD
ANTICIPATE ANOTHER POTENTIAL NON-DIURNAL TEMPERATURE SCENARIO AS ANY
COLD-AIR DAMMING ERODES. BASED ON THE PATTERN WILL ONLY NOTE A
SLIGHT CHANCE OF RAIN OR SNOW EARLY ON THE SIXTH DAY IN THE WESTERN
PIEDMONT WITH A CHANCE OF JUST ALL RAIN THROUGHOUT CENTRAL NORTH
CAROLINA BY TUESDAY AFTERNOON. 1000-850MB THICKNESSES ON THE 12Z GFS
AND 00Z ECMWF ARE QUITE WARM WEDNESDAY...APPROACHING 1380M ON THE
LATEST GFS AND ONLY SLIGHTLY COOLER ON THE 00Z ECMWF...SUCH THAT...
WITH SHOWERY CONDITIONS IN A MOIST AIR MASS AND A SOUTHWEST FLOW
ALOFT...HIGH TEMPERATURES COULD POSSIBLY REACH THE 60S THROUGHOUT
CENTRAL NORTH CAROLINA WITH SOME TEMPERATURES PUSHING OR EXCEEDING
70F ESPECIALLY OVER PARTS OF THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -DJF
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 642 AM WEDNESDAY...
24-HR TAF PERIOD: IFR STRATUS DECK HAS STEADILY SHIFTED SOUTHEASTWARD
OVER THE PAST HOURS AS WEAK SURFACE HIGH BUILDS INTO THE AREA FROM
THE NORTHWEST. SOUNDINGS INDICATE THAT THIS SHRINKING AREA OF LOW
CLOUDS SHOULD MIX OUT RATHER QUICKLY...AOA 14Z WITH VFR CONDITIONS
EXPECTED UNDERNEATH A THICKENING CIRRUS SHIELD.
CONDITIONS WILL DETERIORATE RAPIDLY BETWEEN 00Z TO 03Z AS A LOW
PRESSURE SYSTEM TRACKS FROM THE NORTHERN GULF OF MEXICO TO OFF THE
CAROLINA COAST OVERNIGHT THROUGH EARLY THURSDAY MORNING...SPREADING
WINTRY PRECIP INTO THE AREA. MODERATE TO HEAVY SNOW WILL OVERSPREAD
ALL OF THE TERMINALS IN THE 00Z-03Z TIME FRAME....POSSIBLY MIXING
WITH RAIN AT KFAY. PRECIP WILL GRADUALLY TAPER OFF BETWEEN 12 TO
15Z THU...ENDING AS FREEZING RAIN/DRIZZLE.
LOOKING AHEAD: SUB-VFR CEILINGS WILL LIKELY PERSIST IN THE WAKE OF
THE COASTAL LOW PRESSURE SYSTEM DURING THE DAY THU. VFR CONDITIONS
MAY RETURN FOR A PERIOD ON FRI...THOUGH INTERMITTENT SUB-VFR
CONDITIONS WILL BE POSSIBLE FRI INTO THE WEEKEND IN ASSOC/W THE
UNSETTLED PROGRESSIVE SYNOPTIC PATTERN IN PLACE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON WEDNESDAY FOR NCZ007>011-024>028-
040>043-076>078-085-086-088-089.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST THURSDAY
FOR NCZ078-085-086-088-089.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON EST THURSDAY FOR
NCZ007>011-021>028-038>043-073>077-083-084.
&&
$$
SYNOPSIS...CBL
NEAR TERM...BLAES
SHORT TERM...BLAES/RAH
LONG TERM...CBL/DJF
AVIATION...CBL/BSD/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1105 AM EST WED FEB 25 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE WILL FORM OVER THE NORTHERN GULF
OF MEXICO TODAY AND WILL THEN TRACK QUICKLY NORTHEAST...OFF THE
CAROLINA COAST OVERNIGHT THROUGH EARLY THURSDAY. COLD CANADIAN
HIGH PRESSURE WILL THEN BUILD INTO THE REGION FRIDAY AND INTO THE
WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 1105 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE THROUGH NOON TODAY...
WILL CANCEL THE WINTER WEATHER ADVISORY SHORTLY.
MORNING UPPER AIR ANALYSIS SHOWS THE SHEARING SHORT WAVE
TROUGH OVER TEXAS THIS MORNING WITH SHORT WAVE RIDGING OUT AHEAD OF
IT ACROSS THE SOUTHEAST. HIGH CLOUDS HAVE BEEN ADVANCING NORTHEAST
AHEAD OF THE SYSTEM AND MOST OF CENTRAL NC IS ALREADY UNDER AT LEAST
A THIN VEIL OF CIRRUS. REGIONAL RADAR IMAGERY SHOWS PRECIPITATION
EXPANDING ACROSS THE DEEP SOUTH WITH MEASURABLE PRECIP NOW REPORTED
ACROSS CENTRAL ALABAMA. NO PRECIPITATION IS EXPECTED IN CENTRAL NC
DURING THE TODAY PERIOD BUT TODAYS WEATHER COULD STILL PLAY A ROLE IN
THE IMPACT OF TONIGHTS WINTER STORM. THE TEMPERATURES FORECAST FOR
TODAY IS PROBLEMATIC AS YESTERDAYS SNOWFALL WILL DAMPEN THE
TEMPERATURE RECOVERY THIS AFTERNOON AND ENERGY IS DIVERTED INTO
MELTING AND EVAPORATING SNOW AND MELT WATER. EVEN SO...SOME
GUIDANCE INCLUDING THE HRRR SUGGEST HIGHS IN THE MID 40S TO AROUND
50. NOT READY TO JUMP THAT HIGH BUT CURRENT TEMP AT OUR OFFICE IS 37
AT 1045 AND HAVE MADE A SLIGHT UPWARD ADJUSTMENT IN TEMPERATURES FOR
TODAY. THIS UPWARD TREND IN BOUNDARY LAYER TEMPERATURES WOULD
DELAY THE CHANGEOVER FROM RAIN OR MIXED RAIN AND SNOW THIS EVENING
TO SNOW AND POTENTIALLY LIMIT ACCUMULATIONS A BIT...PRIMARILY
ACROSS THE FAR SOUTHERN TIER IN THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -BLAES
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS OF 1100 AM WEDNESDAY...
*** QUICK 1100 AM UPDATE. QUICK LOOK AT 12Z GUIDANCE NOTES NO
IMMEDIATE OR SIGNIFICANT FORECAST ADJUSTMENTS ARE NEEDED BUT NAM
CONTINUES TO TREND NORTH A BIT AND WITH THE GFS SHOWING A SLIGHT
NORTHWARD ADJUSTMENT.
...WINTER STORM WARNING HAS BEEN ISSUED FOR TONIGHT AND THURSDAY FOR
ALL THE PIEDMONT...NORTHERN/CENTRAL COASTAL PLAIN AND SANDHILLS...
...WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR TONIGHT AND THURSDAY
FOR THE SOUTHERN COASTAL PLAIN...
THERE HAS BEEN A CONTINUED SLIGHT NORTHWARD SHIFT IN GUIDANCE SINCE
YESTERDAY...WHICH EQUATES TO A WETTER AND MARGINALLY WARMER SOLUTION
FOR CENTRAL NC...THOUGH THE OVERALL PATTERN REMAINS UNCHANGED WITH
THE DEAMPLIFICATION/ENE SHEARING OF A SHORTWAVE TROUGH FROM NEAR THE
RIO GRANDE THIS MORNING TO THE MIDDLE ATLANTIC COAST BY THU MORNING.
THE ASSOCIATED FORCING FOR ASCENT ATOP A PAIR OF CLOSELY-SPACED AND
STRONG FRONTAL ZONES DRAPED ACROSS THE NORTHERN GOM TO A SFC LOW
ABOUT MIDWAY BETWEEN CAPE HATTERAS AND BERMUDA...WILL RESULT IN THE
CONTINUED DEEPENING OF A SFC LOW OVER THE NW GOM THIS MORNING.
GUIDANCE IS THEN FAIRLY TIGHTLY CLUSTERED WITH THE TRACK OF A MILLER
"A" SFC LOW ACROSS THE NORTHERN FL PENINSULA THIS EVENING AND
ROUGHLY ALONG THE GULF STREAM TO JUST EAST OF CAPE HATTERAS BY 12Z
THU.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS...THE LACK OF A PARENT
COLD HIGH IS ADMITTEDLY SOMEWHAT CONCERNING. AN ARCTIC SFC HIGH AT
1045 MB WILL BE CENTERED OVER SOUTHERN ALBERTA/SASKATCHEWAN AND WILL
CONSEQUENTLY HAVE LITTLE INFLUENCE AT OUR LATITUDE DURING THE HEIGHT
OF THE STORM TONIGHT. HOWEVER...A VERY FAVORABLE MILLER "A" CYCLONE
TRACK ALONG AND JUST OFFSHORE THE SE COAST...IN CONJUNCTION WITH A
PRECEDING ARCTIC HIGH THAT APPEARS TO BE JUST COLD ENOUGH DESPITE
BEING IN A DRAMATICALLY WEAKENED STATE FROM A COUPLE OF DAYS
AGO...BUT IS STILL CHARACTERIZED BY SFC TEMPERATURES AND DEWPOINTS
MOSTLY IN THE TEENS TO 20S OVER NC THIS MORNING...WILL SUPPORT A
SIGNIFICANT WINTER STORM **WITH A NARROW P-TYPE (SNOW/RAIN)
TRANSITION ZONE AND DEEP NEAR FREEZING ISOTHERMAL PROFILES
CHARACTERISTIC OF MILLER "A` SFC PATTERNS.** PRECIPITATION
RATES...OCCASIONALLY MODERATE TO HEAVY...WILL ONLY SERVE TO ENHANCE
THE DEEP NEAR FREEZING ISOTHERMAL PROFILES RIGHT ALONG THE SNOW/COLD
RAIN INTERFACE...OWING TO MELTING. A LITTLE MIX OF SLEET AND
FREEZING RAIN ARE HARD TO AVOID IN CENTRAL NC WINTER STORMS...AND IN
MILLER "A" STORMS INCLUDING THIS ONE...SUCH OCCURRENCE IS MOST LIKELY
NEAR THE NARROW TRANSITION SNOW/RAIN ZONE. NO APPRECIABLE ICING IS
ANTICIPATED...HOWEVER...IN PART SINCE SURFACE TEMPERATURES ARE
EXPECTED TO HOLD NEARLY STEADY IN THE 29 TO 33 DEGREE RANGE OVER THE
WARNING AREA...AND 32 TO 34 DEGREES OVER THE ADVISORY AREA WHERE
SUCH ICING OCCURRENCE WOULD BE MOST PROBABLE.
DESPITE SOME MINIMAL OVERALL RISE IN THICKNESS VALUES VERSUS THE
SLIGHTLY COLDER AND DRIER SOLUTIONS OF YESTERDAY...PROJECTED PARTIAL
THICKNESS VALUES OVER MOST OF THE PIEDMONT AND NORTHERN COASTAL
PLAIN REMAIN SQUARELY IN THE RANGE TYPICAL OF SIGNIFICANT SNOWSTORMS
IN CENTRAL NC. WITH A SLIGHTLY MILDER SOLUTION COMES A SLIGHTLY
WETTER ONE...LED BY A BLEND OF THE VERY SIMILAR 00Z ECMWF AND
GFS...SO QPF HAS BEEN RAISED TO AROUND ONE HALF INCH OVER THE NW
PIEDMONT TO AS MUCH AS ONE INCH OVER THE SOUTHERN COASTAL PLAIN.
PARTIAL THICKNESS VALUES HEAVILY WEIGHTED TOWARD THE FAVORED 00Z
ECMWF AND GFS...FAVORS MOSTLY SNOW OVER THE PIEDMONT AND NORTHERN
COASTAL PLAIN...WITH A MIX OF SNOW AND A COLD RAIN (OR FREEZING RAIN
WITH LITTLE ACCRUAL WHERE SFC TEMPERATURES OSCILLATE ABOUT THE
FREEZING MARK) OVER THE ADVISORY AREA.
SNOW RATIOS BETWEEN 00-06Z THU OF 10-14:1 PER WPC WWD SLR GUIDANCE
AND SUPPORTED BY THERMAL PROFILES THAT RANGE FROM DEEP NEAR FREEZING
ISOTHERMAL IN THER NARROW TRANSITION ZONE TO WELL BELOW FREEZING...
EXCEPT RIGHT AT THE SURFACE...ALONG AND NORTH OF THE I-40/I-85
CORRIDOR...ARE EXPECTED TO DECREASE PARTICULARLY NEAR NARROW
TRANSITION ZONE TO CLOSER TO 8-10:1 PER WHAT IS TYPICAL OF EVENTS
CHARACTERIZED BY PARTIAL THICKNESS VALUES IN THE ~1285/~1535 METER
RANGE. SLIGHTLY LOWER RATIOS...CLOSER TO 4-6:1 WITHIN THE SNOW/RAIN
TRANSITION ZONE - OR ROUGHLY ALONG THE BOUNDARY OF WINTER STORM
WARNING AND WINTER WEATHER ADVISORY - WHERE THE MIXING WITH A COLD
RAIN WILL RESULT IN A MORE SLUSHY ACCUMULATION VERSUS POINTS
NORTHWARD.
BASED ON THESE RATIOS...AND THE QPF NOTED ABOVE...WIDESPREAD
SNOWFALL ACCUMULATIONS OF 3 TO 6 INCHES ARE LIKELY OVER THE WARNING
AREA...WITH A STRIPE OF 6 TO 8 INCHES ROUGHLY INVOF OR JUST NORTH OF
THE US HIGHWAY 64 CORRIDOR...WITH LOCALLY HIGHER AMOUNTS FROM THE
TRIANGLE TO ROANOKE RAPIDS AND ROCKY MOUNT. MEANWHILE...LESSER
TOTALS OF 1 TO 3 INCHES ARE EXPECTED OVER THE ADVISORY AREA...WHERE
AGAIN...PARTIAL THICKNESS AND SFC TEMPERATURE VALUES MARGINALLY
ABOVE FREEZING WILL SUPPORT A MIXING WITH OR CHANGEOVER TO A COLD
RAIN BETWEEN MIDNIGHT AND 5 AM. EVEN THERE...HOWEVER...THE NORTHERN
PORTIONS OF THE ADVISORY COUNTIES MAY EXCEED WARNING CRITERIA OF 3
INCHES.
THE APPROACH OF A WEAK CLIPPER LOW AND ATTENDING SHORTWAVE TROUGH
WILL CAUSE THE LINGERING STRATUS LAYER AND ASSOCIATED MOSTLY CLOUDY
SKIES TO PRODUCE OCCASIONAL DRIZZLE OR FREEZING DRIZZLE...AFTER
LINGERING LIGHT SNOW...OWING TO A LOSS OF SATURATION ALOFT/IN THE
ICE NUCLEATION ZONE - BUT WITH MINIMAL ADDITIONAL IMPACT. CHILLY
TEMPERATURES IN THE LOWER TO MIDDLE 30S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AS OF 340 AM WEDNESDAY...
SHORTWAVE DISTURBANCES EMBEDDED IN THE CONTINUED SWLY FLOW ALOFT AND
LINGERING LOW-LEVEL MOISTURE OWING TO WHAT WILL LIKELY BE A MOIST
SNOW COVER GROUND(AT LEAST FOR THE NORTHERN TWO-THIRDS OF THE
FORECAST AREA)...WILL RESULT IN RATHER EXTENSIVE CLOUDINESS INTO
SATURDAY. COMBINATION OF THIS CLOUD COVER...SNOW COVER AND THE
ARRIVAL OF ANOTHER FRESH SUPPLY OF ARCTIC AIR INTO THE REGION LATE
THURSDAY NIGHT AND INTO FRIDAY...AS A STRONG +1040MB CANADIAN
SURFACE HIGH BUILDS OVER THE REGION...WILL SUPPORT TEMPERATURES WELL
BELOW NORMAL(15-20 DEGREES FRIDAY AND SATURDAY. DRY WITH HIGHS IN
THE MID 30S NORTH TO POSSIBLY LOWER 40S SOUTH...WITH SATURDAY BEING
THE COLDEST DAY OF THE TWO. LOWS IN THE 20S...WITH SOME TEENS
SATURDAY NIGHT.
FLOW ALOFT FLATTENS OUT TO ZONAL BY SUNDAY WHILE MODERATING CANADIAN
HIGH STARTS TO SHIFT OFF THE MID-ATLANTIC COAST AS A SW-NE ORIENTED
FRONTAL ZONE STRETCHING FROM THE SOUTHERN PLAINS INTO THE OHIO
VALLEY MOVES SLOWLY EASTWARD. MODELS HAVE SLOWED DOWN THE ONSET OF
WAA/SOUTHERLY RETURN FLOW AND RESULTANT PRECIP INTO THE AREA LATE
SUNDAY AFTERNOON/EVENING...BY WHICH TIME AIRMASS LOOKS TO HAVE
MODERATED ENOUGH TO SUPPORT ALL RAIN. IT THEN LOOKS LIKE A WET
PERIOD SUNDAY NIGHT THROUGH EARLY NEXT WEEK AS THE AFOREMENTIONED
FRONT SETTLES SOUTHWARD INTO AREA...EVENTUALLY RETURNING NORTHWARD
AS A WARM FRONT WITH CAD IMPLICATIONS TUESDAY/TUESDAY NIGHT AS HIGH
PRESSURE OVER THE GREAT LAKES/NEW ENGLANDS NOSES SOUTH INTO THE
AREA. PARTIAL THICKNESSES CURRENTLY SUGGEST ALL RAIN FOR NOW...BUT
WILL CONTINUE TO MONITOR.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 642 AM WEDNESDAY...
24-HR TAF PERIOD: IFR STRATUS DECK HAS STEADILY SHIFTED SOUTHEASTWARD
OVER THE PAST HOURS AS WEAK SURFACE HIGH BUILDS INTO THE AREA FROM
THE NORTHWEST. SOUNDINGS INDICATE THAT THIS SHRINKING AREA OF LOW
CLOUDS SHOULD MIX OUT RATHER QUICKLY...AOA 14Z WITH VFR CONDITIONS
EXPECTED UNDERNEATH A THICKENING CIRRUS SHIELD.
CONDITIONS WILL DETERIORATE RAPIDLY BETWEEN 00Z TO 03Z AS A LOW
PRESSURE SYSTEM TRACKS FROM THE NORTHERN GULF OF MEXICO TO OFF THE
CAROLINA COAST OVERNIGHT THROUGH EARLY THURSDAY MORNING...SPREADING
WINTRY PRECIP INTO THE AREA. MODERATE TO HEAVY SNOW WILL OVERSPREAD
ALL OF THE TERMINALS IN THE 00Z-03Z TIME FRAME....POSSIBLY MIXING
WITH RAIN AT KFAY. PRECIP WILL GRADUALLY TAPER OFF BETWEEN 12 TO
15Z THU...ENDING AS FREEZING RAIN/DRIZZLE.
LOOKING AHEAD: SUB-VFR CEILINGS WILL LIKELY PERSIST IN THE WAKE OF
THE COASTAL LOW PRESSURE SYSTEM DURING THE DAY THU. VFR CONDITIONS
MAY RETURN FOR A PERIOD ON FRI...THOUGH INTERMITTENT SUB-VFR
CONDITIONS WILL BE POSSIBLE FRI INTO THE WEEKEND IN ASSOC/W THE
UNSETTLED PROGRESSIVE SYNOPTIC PATTERN IN PLACE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON WEDNESDAY FOR NCZ007>011-024>028-
040>043-076>078-085-086-088-089.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST THURSDAY
FOR NCZ078-085-086-088-089.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON EST THURSDAY FOR
NCZ007>011-021>028-038>043-073>077-083-084.
&&
$$
SYNOPSIS...CBL
NEAR TERM...BLAES
SHORT TERM...BLAES/RAH
LONG TERM...CBL
AVIATION...CBL/BSD/VINCENT
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1247 PM CST WED FEB 25 2015
.UPDATE...
ISSUED AT 1247 PM CST WED FEB 25 2015
LIGHT SNOW ENDED IN THE FAR SOUTHWEST SO MADE SOME ADJUSTMENTS TO
POP AND SKY. OTHERWISE...REST OF FORECAST ON TARGET AS COLD
CANADIAN HIGH PRESSURE CONTINUES TO SHIFT SOUTH ACROSS THE AREA.
UPDATE ISSUED AT 942 AM CST WED FEB 25 2015
LIGHT SNOW CONTINUES TO LINGER OVER THE EXTREME SE CORNER OF
NORTH DAKOTA SO KEPT LOW POPS GOING UNTIL ABOUT 18Z. WIND CHILLS
HAVE WARMED TO ABOVE ADVISORY CRITERIA AND THE ADVISORY HAS BEEN
CANCELED. OTHERWISE...REST OF FORECAST LOOKS GOOD.
UPDATE ISSUED AT 652 AM CST WED FEB 25 2015
TWEAKED POPS BASED ON CURRENT RADAR TRENDS BUT WILL CONTINUE WITH
HIGH PROBABILITIES FOR THE NEXT FEW HOURS AS SHORT RANGE MODELS ALL
HAVE LIGHT SNOW HANGING AROUND IN THE SOUTHWESTERN COUNTIES UNTIL
13 TO 14Z. ANY ADDITIONAL ACCUMULATIONS SHOULD BE MINIMAL.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
SNOW THIS MORNING AND WIND CHILLS TONIGHT WILL BE THE PRIMARY
FORECAST CHALLENGE FOR THE SHORT TERM.
NORTHWESTERLY FLOW ALOFT CONTINUES WITH A WEAK REINFORCING
SHORTWAVE DIGGING THROUGH THE DAKOTAS. THE BAND OF SNOW HAS BEEN A
BIT FURTHER EAST THAN EXPECTED...AND VALLEY CITY HAS BEEN DOWN TO
2SM WITH LIGHT SNOW AND IT LOOKS LIKE GWINNER HAS FINALLY
SATURATED AND IS GETTING SOME SNOW AT THE SFC. THE BAND MATCHES UP
WITH THE 850-700MB FRONTOGENESIS FAIRLY WELL...AND THE NAM HAS
THAT AREA STARTING TO MOVE OFF TO THE SOUTH LATER THIS MORNING.
THAT SEEMS TO FIT PRETTY WELL WITH THE RAP AND HRRR WHICH HAVE THE
QPF PEAKING AROUND 10Z AND THEN TAPERING OFF 3 TO 4 HOURS LATER.
TIME HEIGHT PLOTS FOR OUR SOUTHWESTERN CWA HAVE A GOOD OMEGA
BULLSEYE IN THE GOOD DENDRITIC GROWTH ZONE UNTIL AROUND 12Z.
CONTINUED TREND OF CATEGORICAL POPS IN THE FAR WEST FOR EARLY THIS
MORNING...WITH SOME ADJUSTMENTS FOR CURRENT RADAR TRENDS. RAP PUTS
OUT NEARLY 3 INCHES IN FAR SOUTHERN SARGENT COUNTY...BUT THIS
SEEMS A BIT HIGH GIVEN HOW LONG IT HAS TAKEN OBS SITES TO
SATURATE. CONTINUED WITH 1 TO 2 INCHES IN THE FAR SOUTHWESTERN CWA.
THE PRECIP SHOULD TAPER OFF BY MID MORNING AND WE WILL SEE
DECREASING CLOUDS MOVE SOUTH AS ARCTIC HIGH PRESSURE BUILDS INTO
THE NORTHERN PLAINS. THE HIGH WILL CONTINUE INTO TONIGHT AS THE
MAIN UPPER TROUGH CONTINUES TO DIG SOUTHEASTWARD. WITH CLEARING
SKIES AND THE COLD AIR MASS...WE SHOULD AGAIN GET DOWN TO THE -10
TO -20 RANGE TONIGHT. WINDS WILL DECREASE AS THE CENTER OF THE
HIGH MOVES DOWN INTO WESTERN ND...BUT THINK WE SHOULD HAVE ENOUGH
GRADIENT TO BRING WIND CHILLS DOWN TO ADVISORY LEVELS TONIGHT.
GIVEN THAT THERE IS A CURRENT HEADLINE FOR OUR NORTHEASTERN
COUNTIES AND WIND CHILL ADVISORIES ARE BECOMING A DIME A
DOZEN...WILL HOLD OFF ON ISSUING ONE FOR NOW. THE COLD HIGH
PRESSURE WILL REMAIN THROUGH THURSDAY WITH HIGHS JUST ABOVE ZERO.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
THURSDAY NIGHT THROUGH FRIDAY NIGHT...NORTHWESTERLY FLOW ALOFT
CONTINUES WITH THE CENTER OF THE SFC HIGH FINALLY STARTING TO MOVE
SOUTH AND EAST. WIND CHILLS COULD AGAIN BE AN ISSUE THURSDAY NIGHT
INTO FRIDAY MORNING. THE SOUTHERLY WINDS WILL INCREASE MORE ON
FRIDAY AS HIGH PULLS FURTHER AWAY. TEMPS SHOULD GET UP TO AROUND
10 BY FRIDAY AFTERNOON UNDER THE LATE WINTER SUN BUT WILL STILL BE
WELL BELOW AVERAGE AND WILL FEEL PRETTY RAW WITH THE INCREASING
WINDS. WEAK WARM AIR ADVECTION AND WINDS KEEPING US MIXED WILL
ALLOW TEMPS FRIDAY NIGHT TO FALL ONLY SLIGHTLY BELOW ZERO INSTEAD
OF THE TEENS BELOW.
SATURDAY TO WEDNESDAY...MODELS IN GOOD AGREEMENT WITH THE EXTENDED
LEADING TO HIGH CONFIDENCE FOR MUCH OF THE WEEKEND AND FIRST PART OF
NEXT WEEK. DRY WEATHER WILL CONTINUE ACROSS THE NORTHERN PLAINS WITH
THE ONLY SLGHT CHC FOR -SN BEING TUESDAY INTO WEDNESDAY FOR THE
SOUTHERN AND EASTERN PORTIONS OF THE AREA. 500MB SPLIT FLOW
CONTINUES WITH WESTERN CONUS THROUGH AMPLIFYING INTO THE FIRST PART
OF NEXT WEEK THE 500MB SW TO NE ORIENTED TROUGH AXIS PUSHES ACROSS
THE FA ON TUESDAY...BRINGING THE -SN POTENTIAL. TEMPERATURES NEAR
SEASONAL NORMALS WITH HIGHS IN THE 20S SAT-TUE WITH POST FROPA COLD
FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1247 PM CST WED FEB 25 2015
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD...WITH NW WINDS
SLOWLY DECREASING OVERNIGHT. WINDS COULD GUST OVER 20KT THIS
AFTERNOON...ALONG WITH THE POTENTIAL FOR SOME LOWER STRATOCUMULUS
POSSIBLE. WILL MONITOR THIS...BUT FOR NOW HAVE NOT MENTIONED ANY
CIGS THIS AFTERNOON OR STRONGER WINDS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...HOPKINS
SHORT TERM...JR
LONG TERM...JR/JK
AVIATION...DK
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
306 PM CST WED FEB 25 2015
.TONIGHT - CONFIDENCE...MEDIUM
SNOW CONTINUES TO SLOWLY SHIFT EASTWARD THROUGH SRN WI OVERCOMING
THE DRY LOW LAYERS THAT WERE EVIDENT ON 12Z GRB SOUNDINGS. WITH THE
SATURATION HAS COME VSBYS DOWN TO 1/2 TO 3/4SM AT TIMES...ESP SW OF
KMSN. RADAR ANIMATION CONTINUES TO SUPPORT THE MODEL TRENDS OF
KEEPING BEST ACCUMS ALONG AND SOUTH OF I-94 CORRIDOR WITH THE
SYSTEMS BEST ACCUMS MISSING US ACROSS NORTHERN ILLINOIS. SO WILL
HAVE HIGHEST POPS AND ACCUMS IN THE SOUTHERN COUNTIES. THE OTHER
CONSIDERATION IS THE LAKE EFFECT POTENTIAL. TERMINAL DOPPLER HAS
BEEN SHOWING THE BAND HOLDING OFFSHORE THOUGH RAP SOUNDINGS DO SHOW
ONSHORE COMPONENT WITH DELTA T VALUES OF AROUND 21. EQUILIBRIUM
LEVELS ALSO PUSH 6K FEET. HAVE BUMPED UP SOME AMOUNTS A BIT ESP FROM
SE MKE CNTY THROUGH ERN RAC/ENW COUNTIES. WHILE ICE IS EVIDENT
THERE ARE ENOUGH BREAKS/SLUSHINESS TO ALLOW THE NECESSARY
INSTABILITY TO BE REALIZED FOR THE LAKE EFFECT. SO OVERALL 1-2 OF
SYSTEM SNOW FOR MAINLY SRN HALF OF THE CWA WITH SOME ISOLD 3 INCH
AMOUNTS ADJACENT TO THE LAKE SOUTH OF KMKE TO WI/IL BORDER KENW DUE
TO ADDED INFLUENCE OF LAKE EFFECT.
.THURSDAY - CONFIDENCE...MEDIUM
STILL SEEING SOME LINGERING ONSHORE COMPONENT DURING THE MORNING HOURS
SO THE GFS/NAM IDEA OF HANGING ONTO SOME LES POTENTIAL SEEMS REASONABLE.
ENOUGH NNW FETCH ESTABLISHED BY MIDDAY AND INTO THE AFTERNOON HOURS TO
REMOVE LES FROM GRIDS. 850 THERMAL TROUGH WILL BE IN PLACE WITH 925
TEMPS -17C TO -19C. SO MUCH BELOW NORMAL TEMPS EXPECTED WITH HIGHS UPPER
SINGLE DIGITS/LOW TEENS.
.SHORT TERM...FRIDAY THROUGH SATURDAY NIGHT...FORECAST CONFIDENCE
IS MEDIUM.
HIGH PRESSURE MOVES INTO THE REGION FRIDAY AND WINDS WILL BACK
FROM A MORE NORTHERLY DIRECTION TO THE NORTHWEST AND WEST BY
FRIDAY AFTERNOON. HIGHS FRIDAY WILL GENERALLY BE BETWEEN 10 AND 15.
THIS AREA OF HIGH PRESSURE SHOULD KEEP CONDITIONS QUIET THROUGH
THE DAY SATURDAY.
.LONG TERM...SUNDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE IS
MEDIUM.
ECMWF IS PROGGING A POTENT 140KT 250 MB JET STREAK TO TRANSLATE
INTO THE REGION EARLY SUNDAY. SOUTHERN WISCONSIN WILL BE IN THE
LEFT EXIT REGION WITH SOME ASSOCIATED UPPER LEVEL DIVERGENCE. THIS
ALONG WITH A 500 MB SHORTWAVE DISTURBANCE LOOKS TO BRING A SYSTEM
INTO THE REGION FROM THE SOUTHWEST. THE GFS LOOKS TO BE MORE
BULLISH WITH THE 500 MB ENERGY THAN THE ECMWF ACCORDING TO THE
LATEST RUNS. 850 MB WARM AIR ADVECTION AND SOUTHERLY WINDS WILL
HELP BRING IN MOIST LOW LEVEL AIR AS WELL. THE BULK OF THE QPF
AMOUNTS LOOK TO STAY FURTHER SOUTH...OUT OF OUR FORECAST
AREA...BUT NOT BY MUCH. ALSO...THE ECMWF IS SLIGHTLY FASTER THAN
THE GFS REGARDING THE ONSET OF THE PRECIPITATION BY A FEW HOURS.
STILL SOME UNCERTAINTY AS TO THE LOCATION OF THE MAIN QPF AXIS.
ANOTHER SHOT OF COLD AIR ALONG WITH SOME NORTHWEST WINDS AS HIGH
PRESSURE RETURNS TO THE REGION MONDAY ONCE THE SUNDAY SYSTEM
MOVES OUT.
ANOTHER SYSTEM LOOKS TO MOVE INTO THE REGION FOR TUESDAY AS
ANOTHER PULSE OF 500 MB POSITIVE VORTICITY ENERGY TRANSLATES INTO
THE REGION...ALONG WITH BEING IN THE RIGHT ENTRANCE REGION OF A
STRONG 180KT 250 MB JET STREAK AND UPPER LEVEL DIVERGENCE. THERE
IS STILL MUCH UNCERTAINTY WITH THIS PARTICULAR EVENT. CURRENT SNOW
ACCUMULATIONS COULD BE BETWEEN 5 AND 6 INCHES ACROSS THE FORECAST
AREA. AT THE MOMENT...THE TIMING OF THE BULK OF THE SNOW WILL BE
DURING THE DAY TUESDAY. WE WILL CONTINUE TO MONITOR THE
PRECIPITATION TIMING AND AMOUNTS.
&&
.AVIATION/00Z TAFS/...WATER VAPOR SHOWS SHORTWAVE RIDING EAST
FROM IA. MEANWHILE SURFACE LOW DROPPING SE INTO ERN KS/WRN MO.
MODELS IN GOOD AGREEMENT IN SPREADING SNOW ACROSS REMAINDER OF SE
WI THIS AFTN AND EVE WITH ONSHORE COMPONENT LEADING TO SOME LAKE
EFFECT SNOWS AS WELL. SO EXPECTING SOME IFR CIGS AND PERHAPS SOME
LIFR VSBYS...BUT MOSTLY IFR VSBYS. LAKE EFFECT WRAPS UP THURSDAY
MORNING. SO OVERALL 1-2 OF SYSTEM SNOW FOR MAINLY SRN HALF OF THE
CWA WITH SOME ISOLD 3 INCH AMOUNTS NEAR LAKE MI DUE TO ADDED
INFLUENCE OF LAKE EFFECT.
&&
.MARINE...WIND GUSTS WL GET CLOSE TO SMALL CRAFT ADVY FOR A TIME
TONIGHT AS PRESSURE GRADIENT TIGHTENS DUE TO LOW PRESSURE PASSING
WELL SOUTH OF THE AREA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/THURSDAY AND AVIATION/MARINE...COLLAR
THURSDAY NIGHT THROUGH WEDNESDAY...JTS