Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 310717 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 320 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 255 AM SUNDAY... MID LEVEL RIDGING CURRENTLY OVER EASTERN NC WILL CONTINUE TO SLOWLY SHIFT EASTWARD AS MID LEVEL TROUGH APPROACHES FROM THE WEST. AN ASSOCIATED COLD FRONT WILL REMAIN WELL TO THE WEST AND NORTH OF CENTRAL NC TODAY. HOWEVER... WITH MID LEVEL FLOW BECOMING MORE SOUTHWESTERLY THE POTENTIAL FOR A WEAK DISTURBANCE OR TWO COMBINED WITH SOME WEAK UPSLOPE FLOW WILL LEAD TO A BETTER CHANCE FOR SHOWERS SHOWERS THIS MORNING AND AFTERNOON SHOWERS AND STORMS... PRIMARILY ACROSS THE WESTERN PIEDMONT. HOWEVER... WE MAY SEE SOME SHOWERS AND STORMS DEVELOP ON THE SEABREEZE TODAY AS IT MOVES INTO SOUTHEASTERN/EASTERN COUNTIES THIS AFTERNOON. THE SEVERE THREAT SHOULD REMAIN QUITE MINIMAL AGAIN TO NIL... GIVEN WEAK TO MODEST (AT BEST) MLCAPE... COUPLED WITH WEAK DEEP LAYER SHEAR. THUS... DO NOT PLAN TO MENTION ANY SEVERE THREAT IN THE HWO. HIGH TEMPS WILL AGAIN BE SIMILAR TO YESTERDAY... WITH THE EXCEPTION OF MAYBE A DEGREE OR TWO COOLER IN THE NW PIEDMONT WHERE WE SHOULD SEE A BIT MORE CLOUD COVER AND A BETTER CHANCE OF PRECIP AT TODAY. THUS... WILL GO WITH HIGHS RANGING FROM THE MID TO UPPER 80S ACROSS THE AREA. MOST CONVECTION SHOULD DIE OFF WITH THE LOSS OF DAYTIME HEATING THIS EVENING. OVERNIGHT LOWS SHOULD AGAIN BE GENERALLY IN THE MID TO UPPER 60S. && .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 /06Z SUNDAY THROUGH THURSDAY/... AS OF 150 AM SUNDAY... 24-HR TAF PERIOD: VFR CONDITIONS ARE GENERALLY EXPECTED DURING THE 24 HOUR TAF PERIOD. HOWEVER... PATCHY SUB-VFR CIGS AND/OR VISBYS WILL AGAIN POSSIBLE THIS MORNING... WITH THE HIGHEST LIKELIHOOD OF OCCURRENCE AT KGSO/KINT. IN ADDITION... A FEW SHOWERS WILL BE POSSIBLE AT KGSO/KINT EARLY THIS MORNING NEAR DAYBREAK. ANY SUB-VFR CIGS SHOULD LIFT BY 16Z OR SO AND ANY VISBYS RESTRICTIONS SHOULD END SHORTLY AFTER DAYBREAK (OUTSIDE OF ANY PRECIP). 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 PROB30 FOR STORMS AT 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...BSD SHORT TERM...WSS LONG TERM...WSS AVIATION...BSD/VINCENT

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