Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 191919 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 318 PM EDT TUE MAY 19 2015 .SYNOPSIS...A COLD FRONT WILL MOVE ACROSS CENTRAL NORTH CAROLINA TONIGHT...AND THEN STALL OVER SOUTH CAROLINA ON WEDNESDAY. THE FRONT WILL THEN RETREAT NORTH IN ADVANCE OF AN AREA OF LOW PRESSURE THAT WILL CROSS THE CAROLINAS ON THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 225 PM TUESDAY... SCATTERED SHOWERS AND ISOLD TSTMS HAVE BROKEN OUT ACROSS PARTS OF CENTRAL NC AS EXPECTED...WITH ACTIVITY EXPECTED TO CONTINUE TO EXPAND AND MOVE EAST THROUGH THE REMAINDER OF THE AFTERNOON. LATEST MESOANALYSIS STILL SHOWS THE BEST MOISTURE AND INSTABILITY LOCATED ACROSS OUR EASTERN ZONES...AND SUGGESTS THAT SHOWER/TSTM COVERAGE SHOULD INCREASE AS THEY EVOLVE EASTWARD LATER THIS AFTERNOON. ANOTHER NOTABLE FEATURE IS A MID LEVEL VORT CURRENTLY MOVING E ACROSS NE SC. THIS FEATURE MAY AID THE DEVELOPMENT AND MAINTENANCE OF SHOWER/TSTM ACTIVITY ACROSS OUR SE ZONES AS IT MOVES EAST THE REST OF THIS AFTERNOON. OTHERWISE...GIVEN WEAK MID-LEVEL LAPSE RATES AND WEAK SHEAR...CELL INTENSITY SHOULD BE LIMITED...BUT STILL CAPABLE OF PRODUCING BRIEF INTENSE DOWNPOURS GIVEN THE ABUNDANT MOISTURE AND ABOVE-CLIMO PWAT VALUES IN PLACE ACROSS THE AREA. SHOWER/TSTM ACTIVITY IS THEN EXPECTED TO DIMINISH AND MOVE EAST TOWARD THE COAST LATER THIS EVENING. OVERNIGHT...THE COLD FRONT WHICH IS CURRENTLY EXTENDING FROM PITTSBURGH TO NASHVILLE TO MEMPHIS WILL MOVE S AND E AND ACROSS OUR CWA. LATEST HRRR SUGGESTS AN ISOLD SHOWER CAN`T BE RULED OUT WITH PASSAGE OF THE FRONT...BUT MOST PLACES WILL REMAIN DRY AS THE FRONT MOVES ACROSS. MORE LIKELY WILL BE THE FORMATION OF SOME FOG...ESP ACROSS AREAS THAT RECEIVE HEAVIER RAINFALL THIS AFTERNOON AND EVENING. LOW TEMPS WILL BE COOLEST ACROSS THE NW (AROUND 60) WHERE THE FRONT WILL MOVE THROUGH EARLIER IN THE NIGHT...VERSUS OUR SE ZONES WHERE THE FROPA WILL OCCUR LATER IN THE NIGHT AND THUS HAVE LOW IN THE MID TO UPPER 60S. && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... AS OF 225 PM TUESDAY... THE COLD FRONT WILL STALL TO OUR SOUTH ACROSS SC ON WEDNESDAY. THIS WILL ALLOW DRIER AND SLIGHTLY COOLER AIR TO MOVE INTO OUR AREA FROM THE NW. AS SUCH...LOOK FOR FAIR WEATHER WITH HIGHS FROM THE MID 80S NORTH TO UPPER 80S SOUTH. WEDNESDAY NIGHT...A SHORT WAVE OVER THE MISS VALLEY WILL MOVE EAST AND INDUCE A LOW PRESSURE WAVE ALONG THE OLD BOUNDARY TO OUR SOUTH. THERE ARE STILL MODEL DIFFERENCES REGARDING WHERE (PARTICULARLY HOW FAR NORTH) THAT WAVE WILL SET UP...BUT EITHER WAY IT APPEARS THAT A FEW SHOWERS WILL BE POSSIBLE ACROSS OUR PIEDMONT ZONES LATER OVERNIGHT. LOWS WILL RANGE FROM AROUND 60 NW TO MID 60S SE. && .LONG TERM /THURSDAY THROUGH TUESDAY/... AS OF 315 PM TUESDAY... THURSDAY TROUGH FRIDAY NIGHT: A QUICK MOVING S/W DISTURBANCE IS EXPECTED TO MOVE FROM THE PLAINS TO OFF THE MID-ATLANTIC/NORTHEAST U.S. COAST BY FRIDAY MORNING... SPREADING SHOWERS AND SOME STORMS ACROSS CENTRAL ON THURSDAY. WHILE THE DISTURBANCE WILL TRACK JUST TO OUR NORTH...AN AREA OF LOW PRESSURE IN RESPONSE WILL DEVELOP/DEEPEN ALONG THE OLD FRONTAL ZONE NEAR THE NC/SC BORDER... THEN LIFT NORTH AND EASTWARD ON THURSDAY NIGHT INTO FRIDAY. THIS SHOULD BRING A WIDE RANGE IN TEMPS ACROSS CENTRAL NC ON THURSDAY... WITH THE POTENTIAL FOR SOME ROTATING STORMS NEAR THE BOUNDARY... AS DEEP LAYER SHEAR IS EXPECTED TO INCREASE TO 30 TO 35 KTS WITH A BACKED SURFACE FLOW AS THE SURFACE APPROACHES. HOWEVER... WITH THE POSSIBILITY OF ON GOING SHOWERS AND WIDESPREAD CLOUD COVER THERE IS QUITE A BIT OF UNCERTAINTY WRT HOW MUCH DESTABILIZATION WE WILL SEE IN THE DEVELOPING WARM SECTOR. THUS...SPC HAS PLACED SOUTHEASTERN/EASTERN PORTIONS OF CENTRAL NC IN A MARGINAL RISK FOR SEVERE STORMS. FOR NOW WILL CONTINUE TO MENTION A THREAT FOR ISOLATED SEVERE STORMS ACROSS OUR SE/E COUNTIES IN THE HWO FOR THURSDAY. WILL GO WITH HIGHS TEMPS ON THURSDAY RANGING FROM THE UPPER 60S/NEAR 70 (MAYBE NOT COOL ENOUGH EVEN) NEAR THE NC/VA BORDER TO LOWER TO MID 80S SOUTH/SOUTHEAST. THE PRIMARY SURFACE LOW IS EXPECTED TO LIFT OFF TO THE NORTHEAST LATE THURSDAY NIGHT INTO FRIDAY... BRINGING A RETURN TO DRY AND QUIET WEATHER... WITH CLEARING/SUNNY SKIES BY FRIDAY AFTERNOON ONWARD AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA FROM THE NORTHWEST. EXPECT HIGHS ON FRIDAY WILL BE IN THE UPPER 70S TO LOWER 80S. LOWS FRIDAY MORNING WILL BE DEPENDENT ON THE AMOUNT OF CLEARING AND ANY LINGERING COOL STABLE AIRMASS. FOR NOW WILL GO WITH LOWS RANGING FROM THE 50S NORTH TO THE MID 60S SE. LOWS SATURDAY... WITH SURFACE HIGH PRESSURE TO THE NORTH OF THE REGION... ARE EXPECTED TO BE IN THE MID TO UPPER 50S. SATURDAY THROUGH TUESDAY: SURFACE HIGH PRESSURE WILL MOVE ACROSS THE REGION THIS WEEKEND AND OFFSHORE EARLY NEXT WEEK AS MID LEVEL RIDGING BEGINS TO BUILD AGAIN. THIS WILL YIELD A WARMING TREND EACH DAY FROM HIGHS IN THE UPPER 70S TO LOWER 80S ON SATURDAY TO THE UPPER 80S TO LOWER 90S ON TUESDAY. LOWS WILL FOLLOW A SIMILAR TREND... 50S THIS WEEKEND TO THE MID TO UPPER 60S BY TUESDAY MORNING. DRY CONDITIONS ARE GENERALLY EXPECTED FOR THIS PERIOD... WITH INCREASING CHANCES OF AT LEAST SOME ISOLATED OR WIDELY SCATTERED SHOWERS AND STORMS BY TUESDAY AFTERNOON (BEST CHANCE NORTHWEST) AS LOW LEVEL MOISTURE INCREASES IN RETURN FLOW. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 225 PM TUESDAY... SCATTERED SHOWERS AND TSTMS WILL BE POSSIBLE ACROSS MUCH OF CENTRAL NC THROUGH THE REMAINDER OF THE AFTERNOON. THESE SHOWERS WILL LOCALLY AND BRIEFLY REDUCE CIGS AND VSBY TO IFR OR MVFR. OUTSIDE OF THESE SHOWERS/TSTMS...VFR CONDITIONS CAN BE EXPECTED. THE ACTIVITY WILL WIND DOWN FROM WEST TO EAST THIS EVENING...ENDING AT INT/GSO BY 19/23Z...RDU BY 20/00Z...AND RWI/FAY BY 20/01Z. AREAS OF FOG WILL BE POSSIBLE OVERNIGHT WHERE THE HEAVIEST RAIN OCCURS...BUT CONFIDENCE RIGHT NOW IS STILL TOO LOW TO INCLUDE IN THE TAFS. WITH DRIER AIR ARRIVING BEHIND THE FRONT...EXPECT VFR CONDITIONS DURING THE DAYTIME WEDNESDAY. OUTLOOK: AN AREA OF LOW PRESSURE WILL TRACK ACROSS THE CAROLINAS AND RESULT IN A CHANCE OF SUB-VFR CEILINGS AND RAIN LATE WED NIGHT AND EARLY THU...FOLLOWED BY SHOWERS AND STORMS THU AFTERNOON. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...RAH NEAR TERM...RAH SHORT TERM...RAH LONG TERM...RAH AVIATION...RAH

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