Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 011455
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1055 AM EDT WED APR 1 2015

.SYNOPSIS...
A COLD FRONT WILL PUSH SOUTH OF THE FORECAST AREA TODAY. THE HIGH
PRESSURE CENTER BEHIND THE FRONT WILL BRIEFLY RIDGE INTO THE AREA
TONIGHT. THE HIGH WILL BE OFF THE COAST THURSDAY WITH AN ONSHORE
FLOW INTO THE FORECAST AREA. A WARM FRONT WILL ALSO BE JUST SOUTH
OF THE AREA THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
TODAY...THE BACKDOOR FRONT CONTINUES TO PUSH SOUTHWARD THROUGH
THE CENTRAL MIDLANDS LATE THIS MORNING. CONVERGENCE AHEAD OF THE
FRONT PLUS A MID-LEVEL SHORTWAVE TROUGH WILL HELP SUPPORT SHOWERS
A FEW SHOWERS ACROSS THE SOUTHEASTERN MIDLANDS THE NEXT HOUR OR
SO...THEN THE SHORTWAVE PUSHES EAST AND THE ACTIVITY WILL EXIT THE
CWA. LATER THIS AFTERNOON DRYING WILL OCCUR BEHIND THE COLD FRONT
WITH RISING 500 MB HEIGHTS. TEMPERATURES WILL CONTINUE TO RISE
THROUGH THE AFTERNOON...ALTHOUGH A LITTLE SLOWER IN AREAS NORTH OF
THE FRONT. THIS IS DUE TO SOME LOW-LEVEL COLD ADVECTION PUSHING IN
ON NORTHEASTERLY WINDS. IN GENERAL IT APPEARS AS IF THE LATEST NAM
AND MOSGUIDE HAVE THE BEST HANDLE ON CURRENT TEMPS AND TRENDS.
HAVE GENERALLY BLENDED THOSE RUNS WITH THE LATEST ERLAV
GUIDANCE...AND MADE MINOR TWEAKS TO THAT. THIS GENERALLY GIVES
HIGHS IN THE LOWER 70S NORTH...MIDDLE 70S CENTRAL...AND UPPER 70S
ACROSS THE SOUTH.

TONIGHT...WITH THE FRONT SOUTH OF THE AREA AND WITH HIGH PRESSURE
MOVING ACROSS THE REGION...IT WILL REMAIN DRY. THE MAIN UPPER
LEVEL RIDGE WILL ALSO BE PUSHING INTO AND ACROSS THE AREA
OVERNIGHT. IN GENERAL...USED THE GUIDANCE CONSENSUS FOR THE LOW
TEMPERATURE FORECAST.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE OFF THE COAST WILL DIRECT AN ONSHORE FLOW INTO THE
FORECAST AREA THROUGH THURSDAY NIGHT. THE MODELS DISPLAY A WARM
FRONT IN GEORGIA WITH ISENTROPIC UPGLIDE IN THE FORECAST AREA.
THERE SHOULD ALSO BE MOISTURE AND INSTABILITY ASSOCIATED WITH A
MID-LEVEL SHORTWAVE TROUGH SHOWN BY THE NAM AND GFS THURSDAY
AFTERNOON OR EVENING. THE NAM AND GFS MOS SUPPORT POPS OF 30 TO 40
PERCENT WITH THE GREATER CHANCE THURSDAY AFTERNOON AHEAD OF THE
SHORTWAVE TROUGH AND NEAR THE TIME OF MAXIMUM HEATING. THERE MAY
BE ENOUGH INSTABILITY FOR THUNDERSTORMS ESPECIALLY IN THE SOUTH
PART WHERE THE NAM LOWERS SURFACE-BASED LI/S TO NEAR -4. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE MODELS HAVE BEEN CONSISTENT SHOWING MUCH OF THE ISENTROPIC
LIFT SHIFTED NORTHEAST OF THE FORECAST AREA FRIDAY. FORCING
ASSOCIATED WITH THE APPROACHING COLD FRONT SHOULD REMAIN NORTH OF
THE REGION THROUGH THE DAY. THE SHOWER CHANCE APPEARS LOW. WE
USED THE WARMER TEMPERATURE GUIDANCE BECAUSE OF EXPECTED HEATING
JUST AHEAD OF THE COLD FRONT.

CONVERGENCE AHEAD OF THE COLD FRONT SUPPORTS AN INCREASED SHOWER
CHANCE FRIDAY NIGHT. THERE MAY BE ENOUGH INSTABILITY FOR
THUNDERSTORMS BUT THIS SUPPORT SHOULD BE LIMITED BECAUSE OF
NOCTURNAL COOLING. THE MODELS DISPLAY THE DEEPEST MOISTURE LATE
FRIDAY NIGHT INTO EARLY SATURDAY MORNING. DRYING BEHIND THE COLD
FRONT SHOULD DOMINATE BEGINNING LATE SATURDAY MORNING OR EARLY
SATURDAY AFTERNOON. USED THE WARMER TEMPERATURE GUIDANCE FRIDAY
NIGHT BECAUSE OF CLOUDINESS AND MIXING ASSOCIATED WITH THE FRONT.
THE GUIDANCE MAY BE TOO COOL SATURDAY BECAUSE OF A RELATIVELY WARM
START AND DOWNSLOPE WINDS BEHIND THE FRONT.

THE HIGH PRESSURE CENTER BEHIND THE FRONT SHOULD BE NEAR THE
FORECAST AREA BY LATE SATURDAY NIGHT. EXPECT MOSTLY CLEAR SKIES
AND LIGHT WINDS WITH STRONG NOCTURNAL COOLING. THE GFS AND ECMWF
MOS HAVE LOWS IN THE UPPER 30S TO AROUND 40. THE DRY AIR MASS
SHOULD REMAIN IN PLACE THROUGH SUNDAY AND THE MOS HAS HIGHS NEAR
70.

THE HIGH WILL BE OFF THE COAST MONDAY AND TUESDAY. THE MODELS
INDICATE AN ASSOCIATED ONSHORE FLOW PLUS ISENTROPIC LIFT IN THE
FORECAST AREA. THE GFS AND ECMWF MOS HAVE POPS OF 20 TO 30 PERCENT.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD.

A COLD FRONT IS MOVING THROUGH THE CENTRAL MIDLANDS TAF
SITES...AND WILL BE APPROACHING THE CSRA SITES LATER THIS
AFTERNOON. WINDS WILL BE WESTERLY AROUND 5 TO 7 KNOTS SOUTH OF THE
FRONT...THEN WILL TURN NORTH TO NORTHEASTERLY AFTER THE FRONTAL
PASSAGE. LATER THIS AFTERNOON AND OVERNIGHT...SURFACE HIGH AND
UPPER LEVEL RIDGING WILL PREVAIL. VFR CONDITIONS EXPECTED THROUGH
THE PERIOD.

EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE THURSDAY
AFTERNOON THROUGH SATURDAY AS ANOTHER FRONTAL BOUNDARY STALLS
ACROSS THE REGION.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&

$$





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