Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 111135 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 735 AM EDT FRI JUL 11 2014 .SYNOPSIS...A WEAKENING SURFACE BOUNDARY WILL DRIFT TOWARD THE COAST TODAY. WEAK HIGH PRESSURE WILL SETTLE OVER THE REGION SATURDAY AND SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 305 AM FRIDAY... A NEARLY SATURATED LOW LEVEL AIR MASS WILL SUPPORT THE DEVELOPMENT OF WIDESPREAD LOW CLOUDS ALONG WITH AREAS OF FOG...SOME OF WHICH MAY BE LOCALLY DENSE. EXPECT THE HIGHEST THREAT FOR FOG/LOCALLY DENSE TO OCCUR OVER THE PIEDMONT COUNTIES WHERE INTRUSION OF DRIER AIR HAS CLEARED OUT THE MID-HIGH LEVEL CLOUDINESS. BASICALLY ALONG AND EAST OF HIGHWAY 1 (WHERE BULK OF HEAVIEST SHOWERS/T-STORMS OCCURRED THURSDAY AFTERNOON-EVENING)...THICK LOW CLOUDS SHOULD PREVAIL WITH PATCHES OF FOG (VISIBILITY 1-3 MILES) EXPECTED. A MID LEVEL SHEAR AXIS AND ATTENDANT SURFACE BOUNDARY WAS ALIGNED SSW-NNE OVER THE EAST HALF OF OUR FORECAST AREA EARLY THIS MORNING. THIS FEATURE WILL DRIFT SLOWLY TO THE E-SE. BASED ON MODEL PROJECTION...THIS FEATURE SHOULD BE ALONG OR JUST EAST OF OUR EASTERN PERIPHERY EARLY THIS AFTERNOON. SIMILAR TO THURSDAY...THIS FEATURE WILL AID IN THE DEVELOPMENT OF SCATTERED CONVECTION. EXPECT GREATEST COVERAGE TO BE OVER OUR FAR E-SE COUNTIES WHILE COVERAGE SHOULD DROP OFF APPRECIABLY OVER THE PIEDMONT. IN THE PIEDMONT...PRESENCE OF DRIER MORE STABLE AIR ALOFT SHOULD INHIBIT CONVECTIVE DEVELOPMENT. STILL PLAN TO HOLD ONTO THE SLIGHT CHANCE ALONG AND IMMEDIATELY WEST OF THE HIGHWAY 1 CORRIDOR BUT SOME MODEL PROJECTIONS SUGGEST THAT THIS MAY BE TOO HIGH. PER MODEL SOUNDINGS AND RH CROSS SECTIONS...LOW CLOUDS MAY PERSIST THROUGH MUCH OF THE MORNING...AND POSSIBLY NOT BREAKING IN SOME AREAS UNTIL EARLY-MID AFTERNOON. THIS DELAY IN HEATING SHOULD RESULT IN HIGH TEMPS A COUPLE OF DEGREES SHY OF NORMAL. MAX TEMPS MOSTLY IN THE MID 80S WITH A FEW UPPER 80S SCATTERED ABOUT. TONIGHT...ANY CONVECTION OVER THE EASTERN SANDHILLS AND SOUTHERN COASTAL PLAIN SHOULD QUICKLY DISSIPATE WITH LOSS OF HEATING WITH JUST A STRAY SHOWER POSSIBLE UNTIL MIDNIGHT. AGAIN...MAY SEE AREAS OF LOW CLOUDS OR PATCHY FOG DEVELOP DURING THE OVERNIGHT. MIN TEMPS IN THE MID-UPPER 60S ACROSS THE PIEDMONT TO NEAR 70 IN THE SANDHILL AND COASTAL PLAIN. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... AS OF 305 AM FRIDAY... WEAK HIGH PRESSURE WILL SETTLE INTO CENTRAL NC IN THE WAKE OF THE DEPARTING/DISSIPATING MID LEVEL SHEAR AXIS. WEAK-MODERATE W-NW FLOW WILL ADVECT A DRIER AIR MASS ALOFT. LIMITED MOISTURE AND LACK OF TRIGGERS ALOFT WILL INHIBIT CONVECTIVE DEVELOPMENT MOST LOCATIONS. EXCEPTION WILL BE THE FAR SE WHERE SCATTERED CONVECTION ALONG THE SEABREEZE MAY OCCUR LATE IN THE AFTERNOON-EARLY EVENING. ALSO...ANY CONVECTION THAT DEVELOPS ALONG THE BLUE RIDGE MAY THREATEN THE FAR NW PIEDMONT DURING THE LATE AFTERNOON-EARLY EVENING. DUE TO LIMITED MOISTURE AND WEAK INSTABILITY...HAVE OPTED TO KEEP POPS IN THIS REGION LESS THAN 20 PERCENT. MAY SEE ANOTHER ROUND OF FOG OR PATCHY LOW CLOUDS EARLY SATURDAY. CONSIDERING THE AMOUNT OF DRY AIR ALOFT...THE FOG/LOW CLOUDS WILL QUICKLY LIFT AND DISSIPATE WITHIN AN HOUR OR TWO OF SUNRISE. UNDER MOSTLY SUNNY SKIES...AFTERNOON TEMPS SHOULD RETURN TO NORMAL LEVELS OF UPPER 80S TO AROUND 90. MIN TEMPS SATURDAY NIGHT IN THE UPPER 60S/AROUND 70. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 305 AM FRIDAY... SUNDAY THROUGH SUNDAY NIGHT: MID LEVEL RIDING INTO CENTRAL NC FROM THE SOUTH/SOUTHWESTERN U.S. WILL HOLD ON SUNDAY. THIS WILL RESULT IN GENERALLY A DRY AND HOT DAY ACROSS CENTRAL NC... WITH THE BEST ISOLATED SHOWER/STORM THREAT ACROSS OUR NORTHWEST PIEDMONT COUNTES (FROM POSSIBLE CONVECTION DRIFTING INTO THE AREA FROM THE HIGHER TERRAIN) AND MAYBE ALONG THE SEABREEZE IN OUR SOUTHEASTERN COUNTIES. AFTERNOON LOW LEVEL THICKNESS VALUES ARE EXPECTED TO BE AROUND 5 TO 10 METERS HIGHER THAN ON SATURDAY. THUS... EXPECT WE SHOULD SEE TEMPS WARM INTO THE LOWER TO MID 90S FOR HIGHS. DRY WEATHER IS EXPECTED ON SUNDAY NIGHT WITH NOCTURNAL STABILIZATION AND LACK OF ANY FORCING FEATURES. EXPECT LOW TEMPS MONDAY MORNING WILL BE IN THE LOWER 70S TO POSSIBLY A FEW MID 70S. MONDAY THROUGH THURSDAY: MID/UPPER LEVEL FLOW WILL AMPLIFY EARLY NEXT WEEK ACROSS THE COUNTRY... WITH A DEEP ANOMALOUS FULL LATITUDE TROUGH DEVELOPS AS A DEEP VORTEX DROPS SOUTHWARD FROM CANADA AND TRACKS ACROSS THE UPPER MIDWEST AND GREAT LAKES REGION. THIS WILL HELP SUPPRESS THE RIDGING ALOFT WESTWARD... ACROSS THE WESTERN U.S. AN ASSOCIATED STRONG COLD FRONT FOR THIS TIME OF YEAR WILL APPROACH THE REGION EARLY NEXT WEEK AND MOVE INTO CENTRAL NC LATE TUESDAY INTO WEDNESDAY MORNING. MODEL GUIDANCE THE LAST SEVERAL DAYS HAS SHOWN THIS FRONT POSSIBLY MOVING THROUGH THE AREA. HOWEVER... GUIDANCE IS NOW HANGING THE FRONT UP ALONG EASTERN NC. THIS WOULD LEAD TO CONTINUED UNSETTLED WEATHER POSSIBLY ACROSS (AT LEAST) EASTERN PORTIONS OF THE AREA ON LATE WEDNESDAY INTO THURSDAY UNTIL DRIER MID LEVEL AIR BEGINS TO PUSH INTO THE AREA FROM THE WEST WITH THE DEPARTURE OF THE LEAD IMPULSE IN THE DEEP MID LEVEL FLOW ON WEDNESDAY INTO THURSDAY. EXPECT THE BEST CHANCE OF SHOWERS AND STORMS WILL BE ON TUESDAY INTO WEDNESDAY MORNING AS THE FRONT APPROACHES. GIVEN THE DEEP TROUGH... ALONG WITH PLENTIFUL MOISTURE IN ADVANCE OF THE FRONT EXPECT WE COULD SEE MORE OF AN ORGANIZED SEVERE EVENT... AS DEEP SHEAR PROFILES MAY BE MORE LIKE A SYSTEM IN LATE SPRING/EARLY SUMMER. HOWEVER... MODELS CONTINUE TO SHOW A DECENT AMOUNT OF VARIATION WRT HOW THE DEEP MID/UPPER LEVEL TROUGH WILL EVOLVE. HIGHS DURING THE PERIOD WILL RANGE FROM THE UPPER 80S INTO THE 90S ON MONDAY... TO GENERALLY 80S FOR THE REMAINDER OF THE PERIOD (MAYBE A FEW 90S ACROSS THE SOUTH AND EAST ON TUESDAY). LOW TEMPS TEMPS WILL FOLLOW THE SAME TREND AND DEPEND ON THE ACTUAL TIMING OF THE FRONT. FOR NOW WILL GO WITH LOWS RANGING FROM THE LOWER TO MID 70S TUESDAY MORNING TO THE 60S BY THURSDAY MORNING. && AVIATION /12Z FRIDAY THROUGH TUESDAY/... AS OF 735 AM FRIDAY... A NEARLY SATURATED LOW LEVEL AIR MASS HAS RESULTED IN THE FORMATION OF WIDESPREAD LOW CLOUDS WITH POCKETS OF IFR/LIFR FOG EARLY THIS MORNING. THE WIDESPREAD MVFR/IFR CEILINGS WILL PERSIST THROUGH MUCH OF THE MORNING WITH IMPROVING CONDITIONS EXPECTED TO BEGIN AROUND 14Z- 15Z. AFTER 16Z...AS DRIER AIR BECOMES MORE ESTABLISHED OVER THE WESTERN AND NORTHERN PIEDMONT...SHOULD SEE MVFR CEILINGS LIFT INTO A SCATTERED STRATOCUMULUS FIELD WITH BASES 3500-5000FT. ELSEWHERE...POCKETS OF MVFR CEILINGS WILL PERSIST UNTIL MID AFTERNOON WITH CEILINGS 2500-4000FT EXPECTED. IN ADDITION WILL SEE AN INCREASE IN SHOWER AND THUNDERSTORM COVERAGE OVER THE COASTAL PLAIN THOUGH EXPECT MOST OF THE ACTIVITY TO OCCUR TO THE EAST-SE OF KFAY AND KRWI. FRIDAY NIGHT THROUGH SUNDAY...A WEAK AREA OF HIGH PRESSURE WILL BUILD THEN SETTLE INTO THE REGION. THIS WEATHER SYSTEM SHOULD MAINTAIN VFR CONDITIONS ACROSS CENTRAL NC. THE WEATHER PATTERN WILL GRADUALLY BECOME UNSETTLED EARLY NEXT WEEK AS A LOW PRESSURE SYSTEM APPROACHES FROM THE NORTHWEST. THIS SHOULD LEAD TO AN INCREASE IN LOW AND MID LEVEL MOISTURE...RESULTING IN EARLY MORNING FOG AND LOW CLOUDS. ALSO...EXPECT PERIODS OF MVFR CEILINGS AND VISIBILITY DUE TO SHOWERS AND THUNDERSTORMS IN THE AFTERNOON...ESPECIALLY TUESDAY AFTERNOON INTO TUESDAY NIGHT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...WSS SHORT TERM...WSS LONG TERM...BSD AVIATION...WSS

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