667  
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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