Area Forecast Discussion
Issued by NWS Columbia, SC

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000
FXUS62 KCAE 231515
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1015 AM EST SUN NOV 23 2014

.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHWARD AND INTO THE FORECAST AREA
TONIGHT. THE FRONT WILL BE NORTH OF THE AREA MONDAY AHEAD OF A
COLD FRONT APPROACHING FROM THE WEST. THE COLD FRONT WILL MOVE
THROUGH THE AREA MONDAY NIGHT AND STALL JUST OFF THE COAST
TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
TODAY...
ISENTROPIC LIFT NORTH OF THE WARM FRONT WILL SUPPORT LOW
CLOUDINESS WITH AREAS OF RAIN OR SHOWERS THROUGH THIS AFTERNOON.
THE NAM LI PATTERN SUPPORTS THE WARM FRONT REMAINING SOUTH OF THE
FORECAST AREA THROUGH TODAY. THE CLOUDINESS AND RAIN SHOULD HELP HOLD
DOWN TEMPERATURES. SHEAR WILL BE ON THE INCREASE BUT WITH A LACK
OF SURFACE-BASED INSTABILITY THE SEVERE THREAT TODAY SHOULD REMAIN
LOW.

TONIGHT...
BY THIS EVENING...SURFACE FLOW WILL INCREASE FROM THE
SE AND S AS 50 TO 60 KT LOW-LEVEL JET APPROACHES. THE SHEAR
SUPPORTS A POSSIBILITY OF SEVERE THUNDERSTORMS. ALTHOUGH THE
LIMITING FACTOR WILL BE LITTLE SURFACE-BASED INSTABILITY. THE NAM
DISPLAYS JUST WEAK INSTABILITY WITH SURFACE BASED LI/S -1 TO -2 IN
THE SOUTHEAST SECTION. THE BEST TIME FRAME FOR POSSIBLE STRONG/SEVERE
THUNDERSTORMS AT THIS TIME APPEARS TO BE BETWEEN 6 PM AND 11 PM.
SPC WRF SHOWS A SQUALL LINE MOVING ACROSS THE AREA DURING THE 6 PM
TO 11 PM PERIOD. THE MAIN THREAT FROM ANY SEVERE WEATHER WOULD
LIKELY BE DAMAGING WINDS...BUT WITH DEEP SHEAR NEAR THE WARM
FRONT...AN ISOLATED TORNADO IS ALSO POSSIBLE. WILL CONTINUE TO
MENTION THUNDER SPREADING FROM SE TO NW THROUGH THE EVENING HOURS.
AS FOR OVERNIGHT LOWS...DO NO EXPECT MUCH CHANGE IN TEMPERATURES
ALTHOUGH THEY MAY RISE THROUGH THE EVENING HOURS ACROSS THE
NORTHERN MIDLANDS AS THE WARM FRONT PUSHES THROUGH THE AREA.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
MONDAY...THE COLD FRONT ASSOCIATED WITH THE LOW IN THE PLAINS
WILL TRY TO PUSH EASTWARD ACROSS THE AREA...BUT BY AFTERNOON/EVENING
BECOMES PARALLEL TO THE UPPER FLOW AND WILL LIKELY SLOW OR STALL
ALONG THE COASTAL PLAIN OR JUST OFF THE COAST. THE MID/UPPER FLOW
BEGINS TO BACK IN RESPONSE TO NEXT SHORTWAVE TROUGH DIGGING SEWD
INTO THE MAIN TROUGH AXIS ACROSS THE CENTRAL PORTION OF THE
COUNTRY. THE MODELS ARE STILL IN PRETTY GOOD AGREEMENT THROUGH
MONDAY NIGHT WITH THE FRONT STALLING ALONG THE COAST.

AS FOR TEMPERATURES...EXPECT THEM TO QUITE WARM MONDAY AHEAD OF
THE COLD FRONT AS WINDS PICK UP FROM THE SOUTH/SOUTHWEST. IT WILL
BE BREEZY AT TIMES THROUGH THE DAY...BUT NOT STRONG ENOUGH FOR A
LAKE WIND ADVISORY. ALL OF THE GUIDANCE INDICATES TEMPERATURES IN
THE MID/UPPER 70S AND WILL CONTINUE WITH THAT TREND FOR THE DAY.
WILL BE DRAMATICALLY WARMER MONDAY WITH BREEZY SOUTH/SOUTHWEST
WINDS AHEAD OF THE COLD FRONT WITH ALL OF THE GUIDANCE IN THE
MID/UPPER 70S. BY MONDAY NIGHT...THE FRONT WILL HAVE PUSHED ACROSS
THE CWA...BUT LINGER NEAR THE COAST. EXPECT CLOUDS AND MOISTURE TO
BE CLOSE ENOUGH FOR THE MENTION OF SHOWERS.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
UNCERTAINTIES CONTINUE IN THE FORECAST THROUGH THE MIDDLE OF NEXT
WEEK. LATEST GFS/ECMWF MODELS BEGIN TO SHIFT THE MAIN UPPER
TROUGH AXIS EASTWARD AS ENERGY DROPS INTO THE BASE OF THE TROUGH
ACROSS THE SOUTHERN PLAINS BY TUE/TUE NIGHT. BY TUE NIGHT...BOTH
MODELS BEGIN TO DEVELOP LOW PRESSURE IN THE GULF OF MEXICO AND
BRING A SYSTEM UP ALONG THE EAST COAST. THE 00Z/06Z NAM IS STILL
THE FARTHEST EWD OF THE SYSTEMS BY TUE NIGHT/WED PERIOD.
HOWEVER...BOTH THE GFS/ECMWF HAVE BEEN CONSISTENT OVER THE PAST
COUPLE OF RUNS WITH THIS SYSTEM. HAVE LOWERED HIGHS WEDNESDAY
BECAUSE OF CLOUDS AND EXPECTED PRECIPITATION AND SURFACE WINDS
FROM THE NORTH/NORTHWEST. LOOKS AS THOUGH MOST OF THE CWA WILL
HAVE TEMPERATURES IN THE 40S. THERE WILL LIKELY BY A CHILLY RAIN
ACROSS THE AREA TUESDAY NIGHT INTO WEDNESDAY. BY WEDNESDAY
NIGHT...MODELS SHOW THE SYSTEM PULLING OUT TO THE NORTHEAST AND
AWAY FROM THE REGION. THURSDAY AND FRIDAY...BOTH MODELS HAVE
TROFINESS ACROSS THE EASTERN HALF OF THE COUNTRY WITH THE FLOW
BECOMING MORE ZONAL BY THE WEEKEND. EXPECT HIGH PRESSURE TO BUILD
INTO THE REGION AT THE SURFACE FOR MUCH OF THE REMAINDER OF THE
EXTENDED PERIOD WITH DRY WEATHER THANKSGIVING DAY THROUGH
SATURDAY. EXPECT TEMPERATURES TO REMAIN BELOW NORMAL THROUGH THE
PERIOD.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
EXPECT IFR OR LIFR CONDITIONS THROUGH MUCH OF THE TAF PERIOD.
THE AREA WILL REMAIN NORTH OF THE WARM FRONT TODAY WITH WIDESPREAD
LOW CLOUDINESS AND AREAS OF RAIN OR SHOWERS. THE FRONT MAY LIFT
NORTH OF THE AREA TONIGHT AHEAD OF THE APPROACHING COLD FRONT.
THERE IS A POTENTIAL FOR A SQUALL LINE TO DEVELOP WELL AHEAD OF
THE COLD FRONT AND CROSS THE AREA DURING THE 23Z TO 04Z TIME
FRAME. WINDS ALOFT WILL BE VERY STRONG AND SOME OF THIS WIND MAY
MIX DOWN TO THE SURFACE IN THE POSSIBLE SQUALL LINE OR WITH ANY
OTHER STRONGER SHOWERS OR THUNDERSTORMS WHICH MAY DEVELOP LATE
THIS AFTERNOON AND TONIGHT. BASED ON THE NAM AND 88D VAD WIND
PROFILES WE HAVE INCLUDED LLWS IN THE TERMINAL FORECASTS.

EXTENDED AVIATION OUTLOOK...CEILING AND VISIBILITY RESTRICTIONS
MAY OCCUR IN SHOWERS THROUGH MONDAY ASSOCIATED WITH A COLD FRONT.
WIND GUSTS NEAR 25 KNOTS MAY ALSO OCCUR MONDAY. WIDESPREAD MVFR OR
IFR CONDITIONS MAY OCCUR TUESDAY NIGHT AND WEDNESDAY ASSOCIATED
WITH LOW PRESSURE TRACKING NORTHWARD NEAR THE COAST.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR SCZ030.
GA...NONE.
&&

$$





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