Area Forecast Discussion
Issued by NWS Columbia, SC

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000
FXUS62 KCAE 190005
AFDCAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
805 PM EDT SAT APR 18 2015

.SYNOPSIS...
UNSETTLED AND WET WEATHER PATTERN WILL CONTINUE THROUGH THE
WEEKEND INTO MONDAY. A STRONG COLD FRONT WILL MOVE ACROSS THE
AREA MONDAY NIGHT...SCATTERED STRONG THUNDERSTORMS ARE POSSIBLE
AHEAD OF THE FRONT. HIGH PRESSURE WILL BUILD OVER THE AREA
TUESDAY AND WEDNESDAY BRINGING FAIR AND DRIER CONDITIONS THROUGH
MID WEEK.

&&

.NEAR TERM /UNTIL 7 AM SUNDAY MORNING/...
SHOWERS CONTINUE DIMINISHING ACROSS THE AREA THIS EVENING WITH THE
HEAVIEST RAIN ACROSS THE FAR EASTERN MIDLANDS WHERE A BIT OF
HEATING HELP GENERATE SOME ADDITIONAL INSTABILITY. EXPECT
REMAINING SHOWERS TO DISSIPATE OVER THE NEXT COUPLE OF HOURS AS
THE NEXT SYSTEM MOVES ACROSS THE CENTRAL GULF STATES AND INTO THE
FORECAST AREA LATE TONIGHT. SURFACE WARM FRONT ALONG WITH SHOWERS
AND A FEW RUMBLES OF THUNDER WILL MOVE INTO THE CSRA AFTER
MIDNIGHT...AND ACROSS THE REMAINDER OF THE FORECAST AREA BY
DAYBREAK SUNDAY. HAVE REMAINED WITH LIKELY TO CATEGORICAL POPS BY
DAYBREAK WITH OVERNIGHT LOWS GENERALLY IN THE MIDDLE 60S.

&&

.SHORT TERM /7 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
SURFACE AND UPPER LEVEL LOW PRESSURE MOVING INTO THE
MIDWEST/MISSISSIPPI VALLEY EARLY SUNDAY...WITH SURFACE LOW
DEEPENING OVER INDIANA LATE IN THE DAY. A WARM FRONT MOVING ACROSS
GEORGIA INTO SOUTH CAROLINA SUNDAY MORNING. STRONG LOW LEVEL
CONVERGENCE NOTED FROM THE CSRA NORTH ACROSS THE PIEDMONT. STRONG
LIFT EXPECTED WITH AREA UNDER STRONG UPPER LEVEL DIVERGENCE
ASSOCIATED WITH ENTRANCE REGION 250 MB JET FROM GULF COAST NORTH
ACROSS TENNESSEE. PRECIPITABLE WATER NEAR 2 INCHES...ABOUT 3
STANDARD DEVIATIONS ABOVE NORMAL. WIDESPREAD SHOWERS/POSSIBLE
HEAVY RAIN EXPECTED EARLY AHEAD OF WARM FRONT AS SHORT WAVE TROUGH
APPROACHES FROM SOUTH CENTRAL GEORGIA. AS AIR MASS BECOMES WEAK TO
MODERATELY UNSTABLE...DEEP LAYER SHEAR INCREASING ESPECIALLY
ACROSS CSRA AND SOUTHEAST MIDLANDS. LATEST HIGH-RESOLUTION MODELS
SUGGEST ORGANIZED CONVECTIVE LINE MAY MOVE RAPIDLY ACROSS THE AREA
DURING THE AFTERNOON. ALTHOUGH INSTABILITY FAIRLY WEAK...THERE IS
SOME POTENTIAL FOR SEVERE THUNDERSTORMS MAINLY CSRA/SOUTHEAST
MIDLANDS. AS SHORT WAVE ENERGY LIFTS TO THE NORTHEAST EARLY SUNDAY
EVENING...EXPECT A DECREASE IN POPS AND THUNDERSTORM
THREAT...LOWERED POPS FROM PREVIOUS FORECAST...ESPECIALLY BY
MIDNIGHT. TEMPERATURE FORECAST...WENT A LITTLE BELOW MOS
TEMPERATURES GIVEN CLOUDS/PRECIPITATION DESPITE EXPECTED WARM
ADVECTION.


A STRONG COLD FRONT WILL APPROACH THE REGION LATE MONDAY...LATEST
MODEL MEAN SUGGESTS FRONT WILL MOVE THROUGH CENTRAL MIDLANDS/CSRA
AROUND 03Z-05Z TUESDAY. MODELS INDICATE MODERATE TO STRONG
INSTABILITY...-8 TO -10 SFC BASED LIFTED INDEX/ CAPE > 3000 J/JG
AS TEMPERATURES RISE INTO THE LOW 80S. MOISTURE MAY BE SOMEWHAT OF
A LIMITING FACTOR AS FRONT APPROACHES BUT DEEP LAYER SHEAR STRONG.
APPEARS THERE IS SOME POTENTIAL FOR SUPERCELLS AS 0-3KM HODOGRAPHS
BECOME MORE FAVORABLE. THINK MAIN THREAT DAMAGING WINDS AND LARGE
HAIL DUE TO VERY DRY AIR MID LEVELS AND LOW WET-BULB ZERO HEIGHTS.
BEST CHANCE FOR RAINFALL SHOULD BE DURING THE AFTERNOON HOURS.
SLIGHT RISK OF SEVERE THUNDERSTORMS MONDAY AFTERNOON. POPS
DECREASE FROM WEST TO EAST AS FRONT MOVES THROUGH THE AREA MONDAY
EVENING. LOW POPS BY MIDNIGHT. GUIDANCE TEMPERATURES MEAN APPEARS
ON TRACK.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE BUILDS OVER THE REGION TUESDAY AND WEDNESDAY
BRINGING A REPRIEVE FROM THE UNSETTLED PATTERN. UPPER FLOW BECOMES
ZONAL TO SLIGHTLY NORTHWESTERLY FOR THE SECOND HALF OF THE WEEK
WHICH IS AN MORE UNCERTAIN WEATHER PATTERN. THERE ARE SOME
INDICATIONS OF LOW LEVEL MOISTURE RETURNING ON THURSDAY AND FRIDAY
AND MORE LIKELY BY NEXT WEEKEND. WILL MENTION CHANCE RAIN NEXT
FRIDAY NIGHT INTO SATURDAY WITH SUPPORT FROM LATEST GFS/ECMWF.
TEMPERATURES NEAR NORMAL.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
SCATTERED DIURNAL SHOWERS CONTINUE TO LINGER ACROSS THE REGION BUT
NOT EXPECTED TO IMPACT TERMINALS. WEDGE CONDITIONS AND LOW CIGS
HAVE BROKEN WITH VFR CONDITIONS TO START THE FORECAST PERIOD.
HOWEVER...ALL GUIDANCE SUGGESTS THE STRATUS WILL REDEVELOP DUE TO
ABUNDANT LOW LEVEL MOISTURE IN PLACE AND A WARM FRONT TO THE SOUTH
WILL BEGIN LIFTING NORTHWARD WITH OVERRUNNING TAKING PLACE. EXPECT
MVFR/IFR CIGS TO RETURN BY AROUND 04Z-05Z AND LOWER THROUGH THE
NIGHT AND PREDAWN HOURS. RAIN SHOULD BEGIN TO ARRIVE FROM THE
SOUTH BY 09Z-11Z AS WARM ADVECTION ASSOCIATED WITH THE LIFTING
WARM FRONT MOVES INTO THE REGION. RESTRICTIONS SHOULD CONTINUE
THROUGH THE DAY SUNDAY AS THE SURGE OF MOISTURE AND STRONG
ISENTROPIC LIFT SHIFTS OVER THE TERMINALS INTO MIDDAY/EARLY
AFTERNOON.

THERE IS A POSSIBILITY OF AFTERNOON THUNDERSTORMS TO DEVELOP WITH
SOLAR INSOLATION BUT TIMING AND LOCATION IS UNCERTAIN AT THIS TIME
SO WILL NOT MENTION AND ALLOW LATER SHIFTS TO ADDRESS WITH NEW
MODEL INFORMATION.

&&

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

$$








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