Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 110545 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 145 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 FRIDAY NIGHT/... AS OF 1000 PM THURSDAY... AFTERNOON AND EARLY EVENING CONVECTION HAS STABILIZED MOST AREAS EAST OF US HWY 1...WHILE SPC MESOANALYSIS AND RAP SOUNDINGS SHOW AROUND 500 J/KG MLCAPE AND LESS THAN ONLY 100 J/KG MLCINH OVER THE WESTERN PIEDMONT. THE UPPER TROUGH AND ASSOCIATED VORTICITY MAX ARE STILL TO THE WEST...APPROACHING THE APPALACHIANS THIS EVENING. THE PRIMARY COLD FRONT IS ALSO JUST WEST OF OR BEGINNING TO CROSS THE MOUNTAINS...WITH A SHARP TROUGH IN THE LESS OF THE MOUNTAINS. BLENDED TPW SHOW PW STILL WELL ABOVE 1.5 INCHES. RADAR TRENDS HAVE BEEN DOWNWARD TO JUST A COUPLE ISOLATED SHOWERS OVER DAVIDSON AND RANDOLPH/CHATHAM COUNTIES....AND THE HRRR SHOWS VERY LITTLE QPF AFTER MIDNIGHT. THERE MAY STILL BE A FEW SHOWERS OR AN ISOLATED STORM GIVEN THE AFOREMENTIONED FORCING...ESPECIALLY WITH THE UPPER VORT MAX AND PRIMARY COLD FRONT. WILL LOWER POPS A BIT AREAWIDE...WHILE KEEPING A SLIGHT CHANCE WEST AND CHANCE EAST. ALSO ADDING PATCHY FOG GIVEN THE WIDESPREAD RAIN AND PARTIAL CLEARING AHEAD OF THE FRONT. -BLS FOR FRI/FRI NIGHT: AS THE DAMPENING SHEAR AXIS SHIFTS TO OUR SE IN LINE WITH THE DISSIPATING SURFACE TROUGH... THE HIGHER PW VALUES WILL ACCORDINGLY SHIFT TO THE COASTAL PLAIN... LEAVING A LIGHT NNE LOW LEVEL FLOW AND RELATIVELY (FOR JULY) DRY COLUMN OVER THE NRN AND WRN CWA. MODELS GENERALLY INDICATE VERY LITTLE PRECIP COVERAGE... CONFINING AFTERNOON CONVECTION TO THE COASTAL PLAIN AND SE SANDHILLS WHERE MODELS PROJECT MUCAPE PEAKING AT 1000-1500 J/KG. WILL RETAIN CHANCE POPS HERE WITH ISOLATED CHANCES TO THE NW. A DIP IN THICKNESSES TO SLIGHTLY BELOW NORMAL VALUES SUPPORTS HIGHS OF 85-90. EXPECT LITTLE MORE THAN PATCHY SHOWERS FRI NIGHT. LOWS 66-71. -GIH && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 315 PM THURSDAY... THE MID LEVEL TROUGH AXIS (CURRENTLY MOVING TOWARDS THE AREA) WILL PUSH OFFSHORE ON SATURDAY...WHILE THE MID LEVEL RIDGE TRIES TO BUILD EASTWARD TOWARDS THE REGION. MODELS HAVE TRENDED DRIER FOR THE WEEKEND...ESPECIALLY ON SATURDAY GIVEN THE DRIER AIR FILTERING INTO THE REGION BEHIND THE DEPARTING TROUGH. IN FACT...FORECAST SOUNDINGS INDICATE VERY LIMITED DEEP LAYER MOISTURE...WITH PWAT VALUES PROGGED TO RANGE BETWEEN 1-1.25 INCHES (WELL BELOW NORMAL). THEREFORE... WILL GO WITH A MOSTLY DRY FORECAST FOR SATURDAY. MOISTURE WILL START TO RECOVER SOME ON SUNDAY AND A SURFACE TROUGH WILL SHARPEN UP OVER THE REGION...LEADING TO A BETTER CHANCE OF MOSTLY DIURNAL TYPE STORMS...ALTHOUGH OVERALL COVERAGE SHOULD STILL BE RATHER LOW. LOW LEVEL THICKNESS VALUES ARE PROGGED TO BE NEAR 1420M ON SATURDAY AND GIVEN EXPECTED LACK OF PRECIP...TEMPS SHOULD RISE INTO THE UPPER 80S TO LOWER 90S. BY SUNDAY...LOW LEVEL THICKNESS VALUES ARE EXPECTED TO CLIMB ANOTHER 5-10M...RESULTING HIGH TEMPS A FEW DEGREES WARMER...GENERALLY LOW TO MID 90S (ALTHOUGH MORE CLOUDS MAY BE AROUND WHICH WOULD TEMPER THE WARMING SOME). && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 315 PM THURSDAY... A DEEP VORTEX IS PROGGED TO MOVE SOUTH OUT OF CANADA AND EVENTUALLY ACROSS THE GREAT LAKES THROUGH THE MIDDLE OF NEXT WEEK. THIS WILL RESULT IN A DEEP TROUGH DEVELOPING OVER THE EASTERN HALF OF THE CONUS. THEREFORE...PRECIP CHANCES WILL BE ON THE INCREASE FOR NEXT WEEK...ESPECIALLY LATE TUESDAY INTO EARLY WEDNESDAY AS A FRONT APPROACHES THE AREA. ALSO...GIVEN THIS UNSEASONABLY STRONG TROUGH... THE MID LEVEL FLOW IS EXPECTED TO STRENGTHEN AND THEREFORE THE POSSIBILITY OF AN ORGANIZED SEVERE THREAT WILL EXIST AND THIS WILL BE MONITORED OVER THE NEXT SEVERAL DAYS. THEN THERE IS STILL A GOOD BIT OF UNCERTAINTY WITH REGARDS TO IF THIS FRONT WILL PUSH ALL THE WAY THROUGH THE AREA...BUT FOR NOW IT LOOKS LIKE THE FRONT WILL STALL SOMEWHERE ACROSS THE CAROLINAS. THUS...WILL SHOW A LITTLE DECREASE IN POPS FOR THE LATTER HALF OF THE WEEK...BUT WILL KEEP A CHANCE IN GIVEN THE UNCERTAINTY WITH REGARDS TO WHERE THE FRONT ENDS UP. HIGH TEMPS AHEAD OF THE FRONT ARE EXPECTED TO BE IN THE LOW TO MID 90S ON MONDAY AND POSSIBLY TUESDAY...ALTHOUGH DEPENDING ON THE TIMING OF THE PRECIP...TEMPS COULD BE SLIGHTLY LOWER ON TUESDAY. THEN SLIGHTLY COOLER TEMPS ARE EXPECTED WEDNESDAY AND THURSDAY GIVEN THE DEEP TROUGHING OVER THE EAST COAST AND THE POSSIBILITY THAT THE FRONT WILL PUSH THROUGH THE AREA. && AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 145 AM FRIDAY... A NEARLY SATURATED LOW LEVEL AIR MASS WILL SUPPORT THE DEVELOPMENT OF WIDESPREAD FOG AND LOW CLOUDS OVERNIGHT...AND INTO THE FIRST HALF OF THIS MORNING. THIS SHOULD LEAD TO WIDESPREAD IFR/LIFR CONDITIONS. IN ADDITION...COULD SEE A FEW SHOWERS DEVELOP ALONG A SLOW MOVING SURFACE FRONT OVER THE SANDHILLS AND COASTAL PLAIN OVERNIGHT INTO THE MID MORNING HOURS. BETWEEN 14Z AND 16Z...SHOULD SEE VISIBILITIES AND CEILINGS IMPROVE THOUGH STILL EXPECT MVFR CEILINGS TO OCCUR AT ALL TAF SITES. 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 2000-3000FT. ELSEWHERE...MVFR CEILINGS WILL PERSIST WITH CEILINGS 1500-2800FT 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...HARTFIELD/BLS SHORT TERM...KRD LONG TERM...KRD AVIATION...WSS

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