Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 241859 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 255 PM EDT SUN AUG 24 2014 .SYNOPSIS...A COLD FRONT OVER SOUTH CAROLINA WILL CONTINUE TO PUSH SOUTH THIS AFTERNOON AS HIGH PRESSURE BUILDS INTO THE AREA. A RIDGE OF HIGH PRESSURE WILL EXTEND INTO THE REGION THROUGH MID WEEK AS TROPICAL STORM CRISTOBAL SLOWLY DEVELOPS WELL OFF THE SOUTHEAST COAST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 240 PM SUNDAY... LATEST SURFACE ANALYSIS DEPICTS A 1023MB SURFACE HIGH CENTERED NEAR LAKE ONTARIO THAT EXTENDS SOUTH INTO THE MID ATLANTIC AND CAROLINAS. THE COLD FRONT HAS PUSHED WELL SOUTH OF THE AREA AND WAS ANALYZED OVER SOUTHERN GEORGIA. A NOTICEABLY COOLER AND DRIER AIR MASS CONTINUES TO MOVE INTO THE REGION WITH SURFACE DEW POINTS HAVING FALLEN 3-4 DEGREES SINCE 12Z THIS MORNING. DEW POINTS IN THE UPPER 50S HAVE MADE IT AS CLOSE AS SOUTHEAST VIRGINIA. LINGERING LOW LEVEL MOISTURE COMBINED WITH SOME STEEPENED LOW-LEVEL LAPSE RATES BELOW A SUBSIDENCE INVERSION HAS RESULTED IN A LARGE FIELD OF STRATO-CUMULUS WITH PARTLY TO MOSTLY CLOUDY SKIES. THESE CLOUDS SHOULD TEND TO WANE LATE THIS AFTERNOON FROM NORTHEAST TO SOUTHWEST WITH MORE DRAMATIC CLEARING OCCURRING COINCIDENT AND AFTER SUNSET. THE CLOUDS ARE APT TO LINGER THE LONGEST ACROSS THE WESTERN PIEDMONT BUT SHOULD STILL BREAK TOWARD MID EVENING. MAINLY CLEAR SKIES ARE EXPECTED OVERNIGHT WITH A FEW STRATUS CLOUDS AND SOME HIGH CIRRUS. SOME GUIDANCE IS SUGGESTING A BRIEF PERIOD OF MORE WIDESPREAD STRATUS IS POSSIBLE TOWARD DAYBREAK ACROSS THE COASTAL PLAIN. GUIDANCE CONTINUES TO TREND COOLER WITH LOWS TONIGHT. WHILE THE COOL NORTHEAST BREEZE WITH SOME GUSTS THIS AFTERNOON WILL DIMINISH TO A LIGHT NORTHEAST WIND OVERNIGHT...EXPECT A SUFFICIENT PRESSURE GRADIENT TO REMAIN IN THE REGION TO KEEP WINDS FROM DECOUPLING. WITH THIS IN MIND...EXPECT LOWS IN THE 58-64 RANGE. -BLAES && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
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AS OF 255 PM SUNDAY... A RIDGE OF HIGH PRESSURE ALOFT WILL EXTEND INTO THE OH VALLEY AND SOUTHERN APPALACHIANS ON MONDAY AND MONDAY NIGHT WHILE SURFACE HIGH PRESSURE CENTERED OVER NY/PA EXTENDS INTO THE CAROLINAS. PARTLY TO MOSTLY SUNNY SKIES ARE EXPECTED ON MONDAY AS ANOTHER BUT LESS PRONOUNCED ROUND OF STRATO CUMULUS IS EXPECTED. THE GREATEST CLOUD COVERAGE SHOULD BE CONFINED TO THE COASTAL PLAIN. MOST OF THESE CLOUDS SHOULD DISSIPATE MONDAY EVENING RESULTING IN MAINLY CLEAR SKIES WITH A FEW MORE CLOUDS PERSISTING IN THE COASTAL PLAIN WHERE A NORTHEAST FLOW WILL PROVIDE SOME ENHANCED MOISTURE. NORTHEAST WINDS ON MONDAY WILL RANGE BETWEEN 8-12 MPH WITH GUSTS OF 14-18 MPH. THE COOL AIR MASS SHOULD SUPPORT HIGHS ONLY IN THE 80-85 RANGE WITH OVERNIGHT LOWS WITHIN A FEW DEGREES OF 60. -BLAES FOR TUE/TUE NIGHT: ANOTHER QUIET/DRY/STABLE DAY. SURFACE HIGH PRESSURE RIDGING WILL BE CENTERED TO OUR NE BUT EXTEND STRONGLY SW THROUGH CENTRAL NC... WHILE ALOFT... STRONG RIDGING CENTERED TO OUR WEST WILL EXPAND EASTWARD. MODELS PREDICT CONTINUED VERY LOW PRECIP WATER (NEAR 2 STANDARD DEVIATIONS BELOW NORMAL)... AND BUFR FORECAST SOUNDINGS SHOW DRY AND STABLE MID LEVELS. MAY SEE AREAS OF LOW STRATUS IN THE HOURS AROUND SUNRISE... AS WELL AS A FEW HIGH CLOUDS... BUT OTHERWISE EXPECT ABUNDANT SUNSHINE. A DRY ADIABATIC LOW LEVEL PROFILE SUGGESTS HIGHS IN THE MID 80S... IN LINE WITH STATISTICAL GUIDANCE. A FEW HIGH CLOUDS TUE NIGHT... BUT OTHERWISE CLEAR SKIES ARE ANTICIPATED TUE NIGHT WITH THE SURFACE RIDGE ON TOP OF THE REGION. COOL LOWS OF 58-63. -GIH
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&& .LONG TERM /WEDNESDAY THROUGH SUNDAY/...
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AS OF 255 PM SUNDAY... FOR WED/WED NIGHT: MORE QUIET WEATHER IS EXPECTED... ALTHOUGH A CHANGE IN OVERALL PATTERN IS ON THE HORIZON. THE SURFACE HIGH WILL CONTINUE TO WEAKEN AND SHIFT SW... IN RESPONSE TO MID LEVEL TROUGHING DIGGING OVER SE CANADA INTO THE ST LAWRENCE VALLEY... AND THE CORRESPONDING SURFACE COLD FRONT PUSHING SOUTHWARD INTO THE OH VALLEY. MID LEVEL FLOW WILL REMAIN LIGHT BUT INCREASE FROM THE WNW IN RESPONSE TO THE RIDGE SHIFTING TO OUR SOUTH. PW REMAINS WELL BELOW NORMAL WITH STABLE PROFILES NOTED IN FORECAST SOUNDINGS THROUGH WED... ALTHOUGH AN E-W BAND OF HIGHER PW ASSOCIATED WITH THE COLD FRONT APPROACHING FROM THE NORTH WILL SLOWLY PUSH TOWARD NC WED NIGHT. THIS RETURN TO MORE TYPICAL VALUES ESPECIALLY ACROSS NRN NC SHOULD TRANSLATE INTO THICKENING HIGH CLOUDS WED NIGHT... BUT THE COLUMN REMAINS TOO DRY AND STABLE FOR ANY PRECIP. HIGHS AROUND 85-88 AS THICKNESSES START TRENDING BACK UP TO NORMAL VALUES. LOWS 62-66. FOR THU THROUGH SUN: WHAT IS NOW TS CRISTOBAL IS EXPECTED TO MOVE NORTHEASTWARD WELL OFF THE CAROLINA COAST THU/FRI... WITH NO TANGIBLE IMPACT ON CENTRAL NC. THE DIGGING TROUGH TO OUR NORTH SHIFTS EAST AND DEEPENS DOWN THROUGH AND JUST EAST OF THE CANADIAN MARITIMES/NEW ENGLAND... PUSHING THE BACKDOOR FRONT SOUTHWARD INTO NC... MOST LIKELY IN THE THU NIGHT/FRI MORNING TIME FRAME. THE ECMWF/GFS SPREAD JUST LIGHT FRONTAL PRECIP ACROSS MAINLY THE NRN THIRD OF THE CWA DURING THIS TIME WINDOW... AND GIVEN THE LACK OF A GOOD INFLUX OF MOISTURE WITH THIS FEATURE AND WEAK NW FLOW ALOFT... AS WELL AS THE SUB-500 J/KG MUCAPE AND WEAK SHEAR... MINIMIZING THE SHOWER/STORM POTENTIAL WITH FRONTAL PASSAGE LOOKS LIKE A GOOD MOVE. THE PROGRESSIVE PATTERN ACROSS NRN/CENTRAL NOAM SHOULD LEAD TO A SWIFT SHIFT OF THE TROUGH TO OUT OVER THE NRN ATLANTIC... WITH WEAK/BRIEF MID LEVEL RIDGING OVER THE SOUTHEAST. THE SURFACE HIGH TO OUR NORTH (BEHIND THE FRONT) SHOULD CORRESPONDINGLY MOVE TO OUR NE THEN EAST... AND AS A RESULT... EXPECT THE FRONT TO STALL OUT NEAR THE NC/SC BORDER AND UP THROUGH WRN NC OVER THE WEEKEND BEFORE WASHING OUT. MODELS START TO DIFFER QUITE A BIT IN TERMS OF PLACEMENT AND TIMING OF CONVECTION OVER THE WEEKEND. DESPITE THE PRESENCE OF THE FRONTAL ZONE... THIS PATTERN DOESN`T APPEAR CONDUCIVE FOR HIGH COVERAGE OF SHOWERS/STORMS... ALTHOUGH THE WEAK STEERING COULD MEAN ANY STORMS MAY BE SLOW-MOVING. WILL TREND POPS UP TO NEAR-CLIMATOLOGICAL CHANCES BY SAT/SUN... WITH INCREASING THICKNESSES AND HUMIDITY. EXPECT DAILY HIGHS IN THE MID-UPPER 80S... AND LOWS IN THE MID 60S TO AROUND 70. -GIH
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&& .AVIATION /18Z SUNDAY THROUGH THURSDAY/... AS OF 220 PM SUNDAY... 24 HOUR TAF PERIOD...VFR CONDITIONS HAVE RETURNED TO NEARLY ALL OF CENTRAL NC WITH THE EXCEPTION OF THE TRIAD WHERE KGSO WAS REPORTING A CIG OF BKN030 LAST HOUR. ANY LINGERING DRIZZLE OR SHOWERS SHOULD BE CONFINED TO LOCATIONS WEST OF THE YADKIN AND OUT OF THE RAH TAF LOCATIONS. COOLER AND DRIER AIR IS EXPECTED TO CONTINUE TO PUSH INTO THE REGION THIS AFTERNOON AND TONIGHT. LINGERING LOW LEVEL MOISTURE COMBINED WITH SOME LIMITED SURFACE HEATING TRAPPED BENEATH A SUBSIDENCE INVERSION HAS RESULTED IN A LARGE FIELD OF BKN VFR STRATO- CUMULUS WITH BASES BETWEEN 3-5KFT. THESE CLOUDS SHOULD TEND TO WANE LATE THIS AFTERNOON...ESPECIALLY FROM NORTHEAST TO SOUTHWEST WITH MORE DRAMATIC CLEARING OCCURRING ONCE SUNSET ARRIVES. MAINLY CLEAR SKIES ARE EXPECTED OVERNIGHT WITH SOME SCT STRATUS CLOUDS WITH BASES AROUND 3KFT AND SOME HIGH CIRRUS. SOME GUIDANCE IS SUGGESTING AN HOUR OR TWO OF IFR STRATUS IS POSSIBLE AT KFAY AND KRWI TOWARD DAYBREAK. CONFIDENCE IS LIMITED...SO HAVE OMITTED IT FOR NOW BUT THE POTENTIAL FOR SOME PATCHY LOW STRATUS IN THE EASTERN COASTAL PLAIN SHOULD BE NOTED. ANOTHER ROUND OF MAINLY VFR STRATO-CUMULUS IS EXPECTED ON MONDAY WITH MAINLY SCT CONDITIONS ALTHOUGH THICKER CLOUD COVER AND SOME BKN CONDITIONS WITH CIGS OF 3-5KFT ARE POSSIBLE IN THE COASTAL PLAIN AFFECTING THE KFAY AND KRWI TERMINALS. A NORTHEAST WIND AT 8-11 KTS THIS AFTERNOON WITH GUSTS OF 15-18KTS WILL DIMINISH TO A LIGHT NORTHEAST WIND AT AROUND 6 KTS TONIGHT AND THEN PICK UP AGAIN ON MONDAY WITH SOME GUSTINESS...ESPECIALLY IN THE COASTAL PLAIN. LOOKING FURTHER AHEAD...VFR CONDITIONS ARE EXPECTED TO DOMINATE THROUGH MOST OF THE PERIOD WITH GENERALLY FAIR WEATHER EXPECTED AS HIGH PRESSURE BUILDS INTO THE REGION. A LOW LEVEL NORTHEAST WIND WILL TRANSPORT SOME MOISTURE INTO THE AREA WHICH COULD RESULT IN PERIOD OF LOW STRATUS OR FOG ACROSS THE COASTAL PLAIN ON TUESDAY AND WEDNESDAY MORNINGS. -BLAES && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BLAES NEAR TERM...BLAES SHORT TERM...BLAES/HARTFIELD LONG TERM...HARTFIELD AVIATION...BLAES

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