Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 020527 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 130 AM EDT SAT MAY 2 2015 .SYNOPSIS...AN UPPER LEVEL LOW AND ASSOCIATED SURFACE LOW WILL MOVE EAST OF THE AREA OVER. THIS WILL ALLOW AN AREA OF HIGH PRESSURE TO EXTEND INTO OUR REGION FOR THE WEEKEND...BRINGING TEMPERATURES CLOSER TO NORMAL. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1015 PM FRIDAY... CYCLONIC CIRCULATION AROUND THE DEPARTING UPPER LEVEL LOW WILL MAINTAIN A SMALL THREAT FOR A FEW SHOWERS THROUGH 06Z OVER SECTIONS OF THE EASTERN PIEDMONT AND COASTAL PLAIN. OTHERWISE...MID-UPPER LEVEL FLOW WILL TRANSITION TO AN ANTI-CYCLONIC CURVATURE...LEADING TO SUBSIDENCE AND DECREASING CLOUD COVERAGE. THIS TRANSITION ALREADY OCCURRING IN THE WESTERN PIEDMONT AND SHOULD PROGRESS SLOWLY EAST OVERNIGHT AS THE UPPER LEVEL LOW MOVES FARTHER AWAY. MAY SEE POCKETS OF FOG DEVELOP OVERNIGHT AS TOP SOIL NEARLY SATURATED AND SFC WINDS BECOME CALM AS SKIES SLOWLY CLEAR. WHILE MODEL MOS GUIDANCE NOT SUGGESTING ANY DENSE FOG NOR IS THE LATEST SREF SUGGESTING WIDESPREAD VISIBILITIES BELOW 3 MILES...HAVE TO BELIEVE THAT A FEW SPOTS WILL SEE REDUCED VISIBILITY (1-3MILES) IN THE EARLY MORNING WITH THE THREAT GREATEST IN THE PIEDMONT WHERE SKIES WILL CLEAR SOONER THAN THE COASTAL PLAIN AND SANDHILLS. MIN TEMPS MID-UPPER 40S. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... AS OF 320 PM FRIDAY... ONE LAST RIBBON OF VORTICITY IS EXPECTED TO DROP SOUTH ACROSS THE COASTAL PLAIN AROUND MIDDAY...AND ALL MODELS SHOW A SIGNAL FOR AT LEAST ISOLATED SHOWERS WITH SOME SHALLOW INSTABILITY BEFORE THE ATMOSPHERE DRIES OUT MORE SUBSTANTIALLY AND STRONGER SUBSIDENCE SETS IN. WILL KEEP THE SLIGHT CHANCE POP FROM ROUGHLY ROXBORO TO CLINTON THROUGH MID AFTERNOON. HIGHS 72-76 NORTHEAST TO SOUTHWEST. HIGHS PRESSURE WILL FINALLY BUILD OVERHEAD SATURDAY NIGHT AND SKIES WILL FULLY CLEAR. DESPITE THE GOOD RADIATIONAL COOLING CONDITIONS...THE AIRMASS ACTUALLY MODIFIES SLIGHTLY AND LOWS WILL BE COMPARABLE TO TONIGHT...IF NOT WARMER IN SOME SPOTS WITH UPPER 40S AND LOWER 50S. && .LONG TERM /SUNDAY THROUGH FRIDAY/... AS OF 240 PM FRIDAY... HIGH PRESSURE OVERHEAD ON SUNDAY WILL SLOWLY MIGRATE OFFSHORE BUT CONTINUE TO RIDGE WESTWARD INTO NC THROUGH TUESDAY. A WEAK TROUGH WILL GET SANDWICHED BETWEEN THE EXITING HIGH AND A HIGH OVER THE GREAT LAKES MID-WEEK. ALTHOUGH SOME OF THE MODELS INDICATE A SLIGHT CHANCE FOR SOME SHOWERS IN THE FAR NORTHWEST DURING THE AFTERNOON PERIODS MON-WED...MOST OF THE SHOWER ACTIVITY SHOULD STAY WELL TO THE NORTH AND NORTHWEST. CENTRAL NC WILL REMAIN UNDER HIGH PRESSURE BUT GENERALLY WEAK SURFACE FLOW FOR THE REMAINDER OF THE WEEK. WEDNESDAY THROUGH FRIDAY GETS INTERESTING TO OUR SOUTHEAST AS BOTH THE GFS AND ECMWF GENERATE A TROPICAL LOW PRESSURE SYSTEM OVER THE CARIBBEAN...MOVING SLOWLY NORTH AND STALLING OFF THE CAROLINA COAST. WHILE THERE IS STILL A GOOD DEAL OF UNCERTAINTY WITH THIS SYSTEM GIVEN THAT IT IS FAR OUT IN THE MODEL FORECAST PERIOD...THE FACT THAT BOTH MODELS SHOW SIMILAR FEATURES INCREASES THE CHANCE THAT SOMETHING OF INTEREST WILL DEVELOP OFF THE SOUTHEAST ATLANTIC COAST TOWARD THE END OF THE WEEK. REGARDLESS...ITS EVOLUTION WILL BE SOMETHING TO WATCH. AS FOR TEMPERATURES...STILL EXPECT OUR FIRST EXTENDED PERIOD OF 80 DEGREE DAYS...WITH HIGHS INCREASING ABOUT A DEGREE OR SO A DAY FROM THE MID TO UPPER 70S ON SUNDAY INTO THE LOW TO MID 80S BY FRIDAY. LOWS WILL SEE A SIMILAR TREND...INCREASING FROM THE MID 50S SUNDAY NIGHT INTO THE UPPER 50S TO LOW 60S BY FRIDAY NIGHT. SKIES WILL GENERALLY BE CLEAR TO PARTLY CLOUDY THROUGH MOST OF THE PERIOD...WITH FAIRLY LIGHT WINDS...EXCEPT IN THE SOUTHEAST AS THAT LOW HANGS OFF THE CAROLINA COAST. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 130 AM SATURDAY... SHOWER ACTIVITY CONTINUES TO DIMINISH ACROSS THE AREA... AS THE UPPER LEVEL LOW PULLS AWAY FROM THE COAST AND SURFACE HIGH PRESSURE BUILDS IN SLOWLY FROM THE WEST. AS SKIES SLOWLY CLEAR...MAY SEE POCKETS OF FOG DEVELOP BETWEEN 06 TO 12Z AS TOP SOIL IS NEARLY SATURATED AND SFC WINDS BECOME CALM . EXPECT PREDOMINATELY VFR CONDITIONS ON SATURDAY WITH BROKEN STRATOCU DECK BETWEEN 4-5KT BY THE AFTERNOON...OWING TO SATURATED SOILS. ADDITIONALLY...SHORTWAVE DISTURBANCE DIVING DOWN THE BACKSIDE OF THE DEPARTING UPPER TROUGH DURING DAYTIME HEATING WILL SUPPORT ISOLATED/ SLIGHT CHANCE OF SHOWERS ACROSS THE AREA. GIVEN LIMITED COVERAGE WILL OMIT ANY MENTION IN TAFS. OUTLOOK... VFR CONDITIONS ARE LIKELY TO CONTINUE THROUGH THE WEEKEND IN TO EARLY NEXT WEEK AS HIGH PRESSURE MOVES ACROSS THE AREA. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS/22 NEAR TERM...WSS SHORT TERM...22 LONG TERM...KC AVIATION...30

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