Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 311425 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1025 AM EDT SUN MAY 31 2015 .SYNOPSIS...BERMUDA HIGH PRESSURE WILL EXTEND OVER THE REGION TODAY BEFORE GIVING WAY TO AN APPROACHING COLD FRONT FROM THE NORTHWEST MONDAY. THE FRONT IS EXPECTED TO STALL OVER THE REGION BY MID WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1025 AM SUNDAY... NOT AS MANY AREAS WITH FOG/STRATUS THIS MORNING AS YESTERDAY AS ALL BUT KINT ARE CURRENTLY SHOWING VFR CONDITIONS. A FEW SHOWERS THIS MORNING ACROSS THE NORTHERN PIEDMONT HAVE LARGELY DISSIPATED AS MODELS SHOW EARLIER ISENTROPIC LIFT OVER THE AREA BEING PUSHED WEST AND NORTH OF THE AREA AT THIS TIME. PROSPECTS FOR CONVECTION THIS AFTERNOON WILL ONCE AGAIN BE FOCUSED ON THE NORTHWEST PIEDMONT BUT A FEW FACTORS SUGGEST THAT COVERAGE MAY ONLY BE SCATTERED AND LIKE THE LAST COUPLE OF DAYS...NOT VERY INTENSE. UPPER AIR ANALYSIS FROM THIS MORNING SHOWS A MOISTURE GAP AT 700 MB SOUTHWEST OF THE AREA THAT SHOULD BE ADVECTING THIS WAY LATER IN THE AFTERNOON. THIS IS ALSO SHOWN ON THE RAP SOUNDINGS THIS AFTERNOON WITH MOST OF THE MOISTURE CONFINED TO THE LOW LEVELS. SHEAR REMAINS WEAK AND RAP SOUNDINGS ALSO SHOW INSTABILITY OF ONLY ABOUT 500 J/KG THIS AFTERNOON. THEREFORE WILL ONLY KEEP LOW CHANCE POPS IN THE EXTREME NORTHWEST PIEDMONT WITH SLIGHT CHANCES MAINLY WEST OF HIGHWAY 1 AND IN THE COASTAL PLAIN WHERE SEA BREEZE INFLUENCES COULD BECOME A FACTOR LATER THIS AFTERNOON. EXPECT HIGHS IN THE UPPER 80S TO NEAR 90 DEGREES IN MOST LOCALES WITH LOWS TONIGHT IN THE UPPER 60S. SREF PROBABILITIES INDICATING THAT LOW STRATUS COULD BE AN ISSUE AGAIN MONDAY MORNING...PARTICULARLY IN THE TRIAD. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 245 AM SUNDAY... MODEL GUIDANCE CONTINUES TO TREND TOWARD A SLIGHTLY SLOWER ARRIVAL OF BETTER UPPER SUPPORT TO INITIATE/SUSTAIN SCATTERED CONVECTION ON MONDAY. HAVE REFLECTED THIS BY STARTING MONDAY MORNING OUT WITH PARTLY CLOUDY-MOSTLY SUNNY SKIES AND REMOVING SLIGHT CHANCE POP IN THE NW IN THE MORNING. THE ATMOSPHERE DOES BECOME MOIST AND UNSTABLE ENOUGH TO INITIATE SCATTERED CONVECTION OVER THE NW PIEDMONT BY AFTERNOON WITH JUST ISOLATED CONVECTION EXPECTED ELSEWHERE. MODEL GUIDANCE CONTINUES TO COME INTO GOOD CONSENSUS WITH THE SCENARIO OF A CLOSED UPPER LEVEL LOW DEVELOPING OVER THE TN/LOWER MS VALLEY BY TUESDAY MORNING WITH THE TAIL END OF THE NORTHERN STREAM S/W EXTENDING ACROSS VA. THE SFC COLD FRONT ASSOCIATED WITH THE NORTHERN STREAM S/W IS EXPECTED TO DRIFT SOUTH INTO CENTRAL NC TUESDAY-TUESDAY NIGHT. THE JET HELPING TO USHER THE S/W OFFSHORE COUPLED WITH THE CLOSED LOW TO OUR SW WILL INCREASE UPPER DIVERGENCE OVER CENTRAL NC. WITH A MOIST AIR MASS IN PLACE (PRECIP WATER VALUES 1.5-1.7 INCH RANGE) AND IMPROVING SUPPORT ALOFT...EXPECT SCATTERED TO NUMEROUS SHOWERS AND T-STORMS TO DEVELOP TUESDAY AFTERNOON AND CONTINUE WELL INTO TUESDAY EVENING. SEVERE PARAMETERS NOT ALL THAT ALARMING AS BULK SHEAR GENERALLY 20KTS OR LESS AND THE LOW LEVEL AIR MASS IS SLIGHTLY UNSTABLE. MAIN CONCERN WITH BE LOCALLY HEAVY DOWNPOURS TRAINING REPEATEDLY OVER THE SAME AREA WHICH MAY LEAD TO LOCALIZED NUISANCE FLOODING ISSUES. SINCE THERE IS THE POTENTIAL FOR HEATING ON MONDAY PRIOR TO CONVECTIVE INITIATION...HAVE ADJUSTED MAX TEMPS MONDAY UPWARD A COUPLE OF DEGREES FROM PREVIOUS FORECAST. MAX TEMPS TUESDAY HIGHLY DEPENDENT ON WHEN EARLY MORNING STRATUS BREAKS...ALLOWING FOR PARTIAL SUN BEFORE CONVECTION DEVELOPS. CURRENT FORECAST OF LOW-MID 80S APPEARS ON TARGET. OVERNIGHT MIN TEMPS GENERALLY IN THE MID- UPPER 60S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 320 AM SUNDAY... MODEL TREND HAS BEEN TOWARD A WETTER/MORE UNSETTLED PATTERN THAN COMPARED TO 24 HOURS AGO...MAINLY TIED TO THE CLOSED LOW OVER THE DEEP SOUTH/TN VALLEY. THIS SET-UP WILL MAINTAIN A PLUME OF VERY MOIST AIR OVER CENTRAL NC THROUGH AT LEAST FRIDAY. THIS MOIST AIR MASS COUPLED WITH A STALLED SFC BOUNDARY AND A SERIES OF PERTURBATIONS ALOFT WILL CAUSE PERIODS OF SHOWERS AND T-STORMS THROUGH THE REMAINDER OF THE WORK WEEK. DIFFICULT TO JUDGE THE TIME FRAME WHEN SHOWERS/STORMS WILL BE MOST NUMEROUS. BASED ON UPPER SUPPORT...POTENTIAL FOR ONE OF THE THREE DAYS TO SEE SHOWERS AND STORMS COVERING MOST OF THE REGION TO START THE DAY. PLAN TO HAVE HIGH END CHANCE/LOW END LIKELY POPS WEDNESDAY...THEN GRADUALLY TAPER POPS DOWNWARD THROUGH FRIDAY AS ATMOSPHERE WILL GRADUALLY BECOME DRIER WITH TIME. BY THE START OF THE WEEKEND...EXPECT ATMOSPHERE TO RETURN TO A TYPICAL SUMMERTIME PATTERN AS MODEL GUIDANCE WEAKENS/DISSIPATES THE UPPER LEVEL LOW OVER THE DEEP SOUTH/NORTHERN GULF. AFTERNOON TEMPS WILL BE GENERALLY SUPPRESSED WEDNESDAY AND POSSIBLY THURSDAY DUE TO EXTENSIVE CLOUDINESS AND AREAS OF CONVECTION. LOW LEVEL NE FLOW WEDNESDAY MAY FUNNEL ENOUGH COOL AIR INTO THE NORTHERN PIEDMONT TO RESULT IN MAX TEMPS IN THE MID-UPPER 70S. AS ATMOSPHERE GRADUALLY DRIES OUT...EXPECT AFTERNOON TEMPS TO GRADUALLY RECOVER BACK INTO THE MID-UPPER 80S BY SATURDAY. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... AS OF 645 AM SUNDAY... 24-HR TAF PERIOD: VFR CONDITIONS ARE GENERALLY EXPECTED DURING THE 24 HOUR TAF PERIOD. HOWEVER... PATCHY SUB-VFR CIGS WILL AGAIN POSSIBLE THIS MORNING (11-16Z)... WITH THE HIGHEST LIKELIHOOD OF OCCURRENCE AT KGSO/KINT. IN ADDITION... A FEW SHOWERS WILL BE POSSIBLE AT KGSO/KINT THIS MORNING AS WELL. ANY SUB-VFR CIGS SHOULD LIFT BY 16Z OR SO. ISOLATED TO WIDELY SCATTERED SHOWERS AND STORMS WILL AGAIN BE POSSIBLE THIS AFTERNOON... WITH THE HIGHEST PROBABILITIES OVER THE TRIAD REGION (KGSO/KINT). THUS... HAVE INCLUDED A MENTION OF VICINITY SHOWERS FOR KGSO/KINT DURING THE AFTERNOON/EARLY EVENING. ELSEWHERE... PROBABILITIES ARE TOO LOW TO INCLUDE ANY MENTION OF PRECIP IN THE TAFS. LOOKING AHEAD: CHANCES FOR EARLY MORNING STRATUS/FOG AND AFT/EVE CONVECTION WILL INCREASE AT ALL TERMINALS MON-WED AS A SLOW-MOVING UPPER LEVEL TROUGH APPROACHES THE CAROLINAS/MID-ATLANTIC FROM THE WEST. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BSD/BADGETT NEAR TERM...ELLIS SHORT TERM...WSS LONG TERM...WSS AVIATION...BSD/VINCENT

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