Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 200458 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1255 AM EDT SUN APR 20 2014 .SYNOPSIS...
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LOW PRESSURE OFF THE SOUTH CAROLINA COAST WILL CONTINUE MOVING SLOWLY TO THE NORTHEAST TODAY... AS COOL HIGH PRESSURE NOSES INTO THE REGION FROM THE NORTHEAST. THE OFFSHORE LOW WILL MOVE OUT OVER THE ATLANTIC TONIGHT AND MONDAY... AS MILD HIGH PRESSURE BUILDS INTO THE AREA FROM THE SOUTHWEST THROUGH TUESDAY.
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&& .NEAR TERM /THROUGH SUNDAY NIGHT/... AS OF 925 PM SATURDAY... TONIGHT: VERTICALLY STACKED LOW ALONG THE SOUTHEAST COAST WILL MOVE SLOWLY EASTWARD OFF THE COAST TONIGHT AND INTO THE DAY ON SUNDAY. WHILE THE DEEP SUBTROPICAL FEED HAS SHIFTED OFFSHORE...CONTINUED EASTERLY OVERRUNNING FLOW WILL SUPPORT PERIODS/OCCASIONAL LIGHT RAIN AND OR DRIZZLE OVERNIGHT...WITH THE DEFORMATION BAND OF MODERATE PRECIP CURRENTLY ACROSS THE SOUTHERN PIEDMONT/FOOHTILLS AND MOUNTAINS LIKELY TO PIVOT EASTWARD IN CONCERT WITH THE EASTWARD MOVING BROAD CYCLONIC CIRCULATION CENTER. LOCALIZED 0.25 TO 0.50" IS STILL POSSIBLE UNDERNEATH THIS HEAVIER PRECIP BAND. OTHERWISE...EXPECT LIGHT AMOUNTS OF GENERALLY ONLY A FEW HUNDREDTHS. SUNDAY AND SUNDAY NIGHT... A MODEL CONSENSUS IS FOR PRECIP TO SLOWLY SHIFT SOUTH AND EAST AND OUT OF THE AREA THROUGH LATE MORNING/EARLY AFTERNOON HOURS WITH GRADUAL CLEARING FROM THE NORTH-NORTHWEST AS THE STRENGTHENING SURFACE HIGH BUILDS IN FROM NEW ENGLAND. HOWEVER... IF THE CYCLONIC FLOW LINGERS ALONG THE I-95 CORRIDOR... AS SOME MODELS HINT... THE CLOUDINESS MAY BE SLOWER TO CLEAR. SKIES BECOMING PARTLY SUNNY NW... AND VARIABLY CLOUDY ELSEWHERE SUNDAY. HIGHS GENERALLY IN THE LOWER TO MID 60S...WITH THE WARMEST READINGS ACROSS THE NW PIEDMONT WHERE WE WILL MORE SUNSHINE. MOST AREAS SHOULD BECOME MOSTLY CLEAR WEST OF I-95 SUNDAY NIGHT. LOWS IN THE 40S. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 200 PM SATURDAY... MONDAY AND MONDAY NIGHT: HIGH CONFIDENCE THAT MONDAY AND MONDAY NIGHT WILL BE DRY AS THE COASTAL LOW MOVES AWAY FROM THE CAROLINAS. SURFACE HIGH PRESSURE WILL CONTINUE TO RIDGE IN FROM THE NORTHEAST WHILE RIDGE ALSO BUILDS IN ALOFT. EXPECT HIGHS AROUND 70 DEGREES AND OVERNIGHT LOWS AROUND 50 DEGREES. TUESDAY THROUGH TUESDAY NIGHT: AN UPPER LEVEL TROUGH WILL APPROACH THE AREA EARLY TUESDAY. THE SURFACE TROUGH AMPLIFIES THE SURFACE LOW OVER THE GREAT LAKES MOVES ENE AND DEEPENS ON TUESDAY. RAIN CHANCES WILL INCREASE TUESDAY AFTERNOON AS THE COLD FRONT APPROACHES. ALTHOUGH SOUTHWEST FLOW IS EXPECTED TO ADVECT IN SOME WARM MOIST AIR AHEAD OF THE FRONT...THE DURATION IS RELATIVELY SHORT...LIMITING THE AVAILABLE MOISTURE AND POTENTIAL RAINFALL TOTALS. AS OF THE LAST COUPLE OF MODEL RUNS...THE GFS APPEARS WETTER THAN THE ECMWF WITH THIS SYSTEM...NOT HELPING TO IMPROVE CONFIDENCE. THE WARM SOUTHWEST FLOW WILL HELP HIGH TEMPERATURES REACH THE MID TO UPPER 70S ACROSS THE AREA. GIVEN THE PROJECTED MARGINAL SHEAR AND INSTABILITY TUESDAY AFT/EVE...AN ISOLATED STRONG/SEVERE STORM CANNOT BE RULED OUT...BUT THE BEST UPPER LEVEL SUPPORT IS WELL TO THE NORTH...WHICH SHOULD HELP LIMIT THE THREAT. REGARDLESS...EXPECT THE COLD FRONT TO MOVE THROUGH CENTRAL NC TUESDAY EVE/NIGHT...WITH DRY AIR ADVECTING INTO THE MID LEVEL BEHIND IT HELPING CUT OFF ANY REMAINING PRECIPITATION. THOUGH IT WILL BE DEPENDENT ON TIMING OF THE FRONT...FOR NOW EXPECT LOWS AROUND 50 DEGREES NW TO MID 50S SE TUESDAY NIGHT. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 215 PM SATURDAY... HIGH PRESSURE BUILDS IN BEHIND THE FRONT AND REMAIN IN PLACE THROUGH THURSDAY NIGHT...YIELDING DRY WEATHER AND TEMPERATURES WITHIN A FEW DEGREES OF NORMAL...HIGHS IN THE LOW TO MID 70S AND LOWS INCREASING FROM MID 40S WEDNESDAY NIGHT TO LOW 50S THURSDAY NIGHT. ANOTHER LOW PRESSURE SYSTEM TRAVERSING EASTWARD ACROSS THE NORTHERN U.S. AT THE END OF THE WEEK WILL GRADUALLY PUSH THE HIGH OFFSHORE AND YIELD THE RETURN OF SOUTHWEST FLOW AND INCREASING RAINFALL CHANCES FOR FRIDAY AND SATURDAY. AGAIN WITH THIS SYSTEM THE MODELS DIFFER...WITH THE GFS BEING THE WETTER OF THE TWO...THUS WILL CONTINUE TO INDICATE A SLIGHT CHANCE FOR RAIN...ALTHOUGH CONFIDENCE IN THE TIMING AND AMOUNTS IS NOT PARTICULARLY HIGH AT THIS TIME. EXPECT HIGHS IN THE MID 70S TO AROUND 80 DEGREES AND LOWS IN THE MID TO UPPER 50S FRIDAY NIGHT...DECREASING INTO THE LOW TO MID 50S FOR SATURDAY NIGHT. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/...
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AS OF 1255 PM SATURDAY... THE COMBINATION OF STRONG LOW PRESSURE OFF THE SC COAST AND A NARROW WEDGE OF COOL HIGH PRESSURE NOSING INTO NC FROM THE NORTH IS KEEPING THICK MAINLY VFR CLOUDS OVER CENTRAL NC... AND THIS SHOULD PERSIST THROUGH THE MORNING. CONFIDENCE IN THE DETAILS OF THE AVIATION FORECAST FOR CENTRAL NC IS LOW... GIVEN POOR MODEL PERFORMANCE IN THE LAST DAY OR SO AND LACK OF MODEL AGREEMENT ON A SOLUTION. BUT BASED ON EXTRAPOLATION OF UPSTREAM CONDITIONS AND THE MOST PLAUSIBLE MODEL SOLUTION... EXPECT CENTRAL NC TAF SITES TO SEE THICK VFR CLOUDS HOLD THROUGH MIDDAY (AROUND 17Z) WITH PATCHY SPRINKLES OR DRIZZLE... ALTHOUGH FAY HAS THE BEST CHANCE OF SEEING A FEW HOURS OF LOWER MVFR CIGS THIS MORNING. THERE MAY EVEN BE A PERIOD OF FAIR SKIES WITH A THIN DECK OF MID CLOUDS BASED AOA 8 000 FT AGL THIS MORNING. FORECAST CONFIDENCE DROPS THIS AFTERNOON WITH THE NAM SHOWING VFR CLOUDS RETURNING... AROUND 4 000 FT THICK... TRENDING SLOWLY DOWN TO MVFR BY MID EVENING... WHILE THE GFS SHOWS A TREND TO MOSTLY CLEAR SKIES BY EVENING. PREFER THE PESSIMISTIC SOLUTION WITH GREATER CLOUD COVER... BUT TAFS WILL FEATURE CLOUDS HOLDING MAINLY VFR WITH A CHANCE OF MVFR TOWARD THE END OF THE FORECAST PERIOD. VSBYS SHOULD REMAIN PREDOMINANTLY VFR THROUGHOUT. SURFACE WINDS WILL REMAIN BRISK FROM THE NE AT 12-17 KT SUSTAINED WITH SPORADIC GUSTS TO 22-30 KTS AT ALL SITES THROUGH THE TAF FORECAST PERIOD. LOOKING BEYOND 06Z EARLY MONDAY MORNING... AS THE OFFSHORE LOW MOVES AWAY AND OUT TO SEA... VFR CONDITIONS ARE EXPECTED TO DOMINATE THROUGH MONDAY NIGHT... ALTHOUGH RWI/FAY MAY SEE A PERIOD OF OVC IFR STRATUS LATE TONIGHT THROUGH MONDAY MORNING. THE NEXT SYSTEM WILL IMPACT THE AREA ON TUESDAY... BRINGING ANOTHER CHANCE FOR RAIN AND ASSOCIATED ADVERSE AVIATION CONDITIONS. HOWEVER... THIS WILL BE A MUCH MORE PROGRESSIVE SYSTEM THAN THE CURRENT ONE... WITH CONDITIONS IMPROVING TO VFR LATE TUESDAY NIGHT INTO WEDNESDAY. VFR CONDITIONS SHOULD THEN PERSIST THROUGH THURSDAY AS HIGH PRESSURE DOMINATES. -GIH
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...CBL/BADGETT SHORT TERM...KC LONG TERM...KC AVIATION...HARTFIELD/KRD

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