Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 252335 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 735 PM EDT MON AUG 25 2014 .SYNOPSIS...
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HIGH PRESSURE WILL EXTEND SOUTHWARD INTO THE REGION THROUGH WEDNESDAY. A WEAK BACK DOOR FRONT WILL APPROACH FROM THE NORTH EARLY THURSDAY.
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&& .NEAR TERM /THROUGH TONIGHT/... AS OF 230 PM MONDAY... SURFACE HIGH PRESSURE REMAINS ANCHORED OVER THE MID-ATLANTIC SETTING UP A NORTH NORTHEASTERLY FLOW REGIME OVER CENTRAL NC. THIS COUPLED WITH MOISTURE BEING ADVECTED INTO THE EASTERN HALF OF THE AREA NEAR THE 850 MB LEVEL HAS BROUGHT BROKEN CEILINGS TO THE EASTERN HALF OF THE CWA WITH MOSTLY CLEAR SKIES TO THE WEST. THIS SETS UP THE FORECAST PROBLEM OF THE DAY TO BE MAXIMUM TEMPERATURES. AS EXPECTED...THE SOUTHWEST PIEDMONT HAS HAD THE HIGHEST TEMPERATURES SO FAR...REACHING THE LOWER 80S. EVERYWHERE ELSE IN THE CWA WILL STRUGGLE TO REACH 80 DEGREES THIS AFTERNOON AND MOST LOCATIONS PROBABLY WILL NOT MAKE IT OUT OF THE UPPER 70S. DEWPOINTS IN THE NORTHWEST PIEDMONT ARE IN THE MID TO UPPER 50S WITH MID 60S TO NEAR 70 IN THE EAST. A SLIGHTLY MORE EASTERLY COMPONENT TO THE LOW LEVEL WINDS WILL PUSH THIS CLOUD COVER FURTHER TO THE WEST LATER THIS AFTERNOON AND INTO THE EVENING. WOULD NOT BE SURPRISED TO SEE SCATTERED TO BROKEN CLOUDS EVERYWHERE BY LATE EVENING. REGARDLESS OF CLOUDS...THE DEPTH OF THE MOISTURE IS VERY SHALLOW AND DRY WEATHER IS EXPECTED TO PREVAIL THROUGH THE NEAR TERM. LITTLE IN THE WAY OF FOG OR LOW STRATUS IS EXPECTED OVERNIGHT. PERHAPS SOME MORE CLOUD COVER OVERNIGHT THAN ORIGINALLY ANTICIPATED SO WILL ADJUST LOW TEMPS ACCORDINGLY...LOW TO MIDDLE 60S NORTH TO SOUTH. WIND GUSTS THIS AFTERNOON OF 15-20 KTS WILL SUBSIDE THIS EVENING. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 230 PM MONDAY... MORE OF THE SAME IS HIGH PRESSURE REMAINS OVER THE MID-ATLANTIC STATES. COMPARED TO MONDAY...THE HIGH WILL BE MORE DIRECTLY OVERHEAD AND THEREFORE WILL LEAD TO LIGHTER WINDS..ESPECIALLY IN THE WEST WITH THE OCCASIONAL GUST TO 15 KTS STILL POSSIBLE IN THE EAST. VERY DRY ATMOSPHERIC SOUNDINGS INDICATING THAT CLOUD COVER NEAR 850 MB WILL BE THINNING OUT BY TOMORROW MORNING DOWN TO FEW OR SCATTERED CLOUDS NEAR 5 KFT AT THE MOST. THICKNESS VALUES ARE EXPECTED TO BE SLIGHTLY HIGHER IN THE WEST WHICH WITH NEAR FULL SUN EVERYWHERE WOULD LEAD TO A FAIRLY EVEN HIGH TEMPERATURE DISTRIBUTION TOPPING OUT IN THE MID-80S. MOSTLY CLEAR SKIES TUESDAY NIGHT AND FAIRLY CALM WINDS WILL LEAD TO A GOOD PERIOD OF RADIATIONAL COOLING...ALLOWING MINIMUM TEMPERATURES TO DROP INTO THE UPPER 50S TO LOWER 60S. -ELLIS FOR WED/WED NIGHT: MORE QUIET WEATHER EXPECTED. WHAT IS NOW TS CRISTOBAL IS EXPECTED TO BE WELL EAST OF CHS WED MORNING... HEADING NE WITH NO CONSEQUENCE FOR CENTRAL NC`S WEATHER. THE SURFACE HIGH WILL START THE DAY CENTERED OVER THE WRN CAROLINAS... BEFORE SLOWLY WEAKENING AND SHIFTING TO THE SW. THIS SHIFT WILL BE IN RESPONSE TO MID LEVEL TROUGHING DIGGING OVER SE CANADA/NRN NEW ENGLAND AND ITS CORRESPONDING SURFACE COLD FRONT PUSHING SOUTHWARD INTO THE OH VALLEY AND MIDATLANTIC THROUGH WED NIGHT. PW VALUES WILL REMAIN WELL BELOW NORMAL FOR MUCH OF THE DAY WITH HIGHLY STABLE/DRY PROFILES NOTED IN FORECAST SOUNDINGS. WHILE AN E-W BAND OF HIGHER PW ASSOCIATED WITH THE COLD FRONT APPROACHING FROM THE NORTH WILL SLOWLY PUSH IN NRN NC WED NIGHT... EXPECT LITTLE MORE THAN THICKENING HIGH CLOUDS WED NIGHT ESPECIALLY NORTH... AS THE COLUMN REMAINS TOO DRY AND STABLE FOR ANY PRECIP. HIGHS AROUND 87-90 AS THICKNESSES START TRENDING BACK UP TO NORMAL VALUES. LOWS 63-66 UNDER FAIR SKIES. -GIH && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 150 PM MONDAY... FOR THU/THU NIGHT: MODEL TIMING DIFFERS A BIT BUT EXPECT THE FRONT TO DROP SOUTHWARD INTO NC SOMETIME THU... MOST LIKELY PUSHING WELL THROUGH THE NORTHEAST QUARTER OF NC BASED ON THE ORIENTATION OF THE DEEPENING MID LEVEL TROUGH TO OUR NNE. THE SURFACE REFLECTION OF THE FRONTAL ZONE WILL BE WEAKENING HOWEVER... AS LOW LEVEL THICKNESSES APPEAR TO DIP LITTLE (IF AT ALL)... BUT WE SHOULD SEE INCREASED CLOUDS AND RISING (BUT STILL LOW) CHANCES FOR SHOWERS/STORMS WITHIN THE INCREASING (BUT STILL WEAK) NORTHWESTERLY MID LEVEL FLOW. MODELS GENERALLY DEPICT SCATTERED AFTERNOON STORMS OVER THE NW NC MOUNTAINS AND FOOTHILLS... DIMINISHING TO JUST ISOLATED CONVECT OVER NE NC AFTER SUNSET. GIVEN THE LACK OF LOW LEVEL MOISTURE TRANSPORT... RISING HEIGHTS ALOFT... AND SUB-750 J/KG MUCAPE... DOWNPLAYING THE CONVECTIVE COVERAGE LOOKS GOOD. ABOVE-NORMAL HIGHS 87-92 AND LOWS 65- 70. FOR FRI THROUGH MON: SHOULD BE A WARM AND MOSTLY DRY START TO THE HOLIDAY WEEKEND... WITH INCREASED STORM CHANCES TO FINISH IT OFF. THE MID LEVEL TROUGH OVER THE CANADIAN MARITIMES WILL SHIFT QUICKLY OUT OVER THE NRN ATLANTIC AS STRONG RIDGING BUILDS OVER THE SOUTHEAST STATES FRI/SAT. WHATEVER IS LEFT OF THE LOW LEVEL FRONTAL ZONE VANISHES FRI... REPLACED BY SURFACE LEE TROUGHING THROUGH THE PIEDMONT FOR SAT. LOW LEVEL MOISTURE DOES START TO IMPROVE ESPECIALLY OVER THE WRN CWA FRI/SAT BUT REMAINS MUTED... AND THE DEEPLY WARM/STABLE MID LEVELS AND VERY WEAK DEEP LAYER SHEAR WILL GREATLY LIMIT CONVECTION POTENTIAL. WILL KEEP POPS AT A SLIGHT CHANCE OR LOWER... BELOW CLIMATOLOGICAL VALUES... FRI/SAT. ATTENTION THEN TURNS TO THE SHORTWAVE TROUGH OVER THE SRN HIGH PLAINS FRI AS IT SHIFTS EAST THEN NE INTO THE GREAT LAKES (PUSHED BY A STRONG PACIFIC NW UPPER JET)... GRADUALLY DAMPENING IN THE PROCESS AS IT GETS DEFLECTED BY THE STILL-FORMIDABLE RIDGE OVER THE SOUTHEAST. THE GFS/ECMWF DO SHOW THIS TROUGH HELPING TO BEAT DOWN THE RIDGE SOMEWHAT... PUSHING THE RIDGE AXIS SOUTHWARD TO SRN GA/FL AND THE ERN GULF. THE STRENGTHENING MID LEVEL SW FLOW AS WELL AS THE INCREASING SE/SRLY CONFLUENT LOW LEVEL FLOW SHOULD PUSH THE CHANCE FOR SHOWERS/STORMS BACK UP NEAR AND JUST ABOVE CLIMATOLOGY SUN/MON... AND WILL SHOW THIS ANTICIPATED TREND IN THE FORECAST. MODEL FORECAST THICKNESSES STAY AT 10-15 M ABOVE SEASONAL NORMALS THROUGHOUT THE HOLIDAY WEEKEND... SO WILL HOLD ONTO HIGHS IN THE UPPER 80S TO NEAR 90... WITH MORNING LOWS IN THE UPPER 60S TO AROUND 70. -GIH && .AVIATION /00Z TUESDAY THROUGH SATURDAY/...
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AS OF 730 PM MONDAY... 24-HR TAF PERIOD: VFR CONDITIONS AND A LIGHT NORTHEAST BREEZE WILL RULE THROUGH THE TAF PERIOD AS DRY HIGH PRESSURE EXTENDS SOUTHWARD INTO THE CAROLINAS. VFR CEILINGS WITH BASES 4000-6000 FT AGL WILL DISSIPATE THIS EVENING...CLEARING OUT BY 00-02Z AT THE RDU/RWI TERMINALS AND BY 02-04Z AT THE FAY TERMINAL. EXPECT VFR CONDITIONS AND CLEAR OR MOSTLY CLEAR SKIES OVERNIGHT AND TUESDAY WITH A NORTHEAST BREEZE AT 5-10 KT. LOOKING AHEAD: VFR CONDITIONS WILL PREVAIL THROUGH MID-WEEK AS DRY HIGH PRESSURE PERSISTS OVER THE CAROLINAS. A SMALL CHANCE FOR ISOLD CONVECTION WILL RETURN THU/FRI AS A WEAK BACKDOOR FRONT DRIFTS INTO THE REGION FROM THE NORTH...THOUGH VFR CONDITIONS SHOULD STILL PREVAIL AT MOST (IF NOT ALL) TERMINALS. -VINCENT
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...ELLIS/BSD SHORT TERM...ELLIS/HARTFIELD LONG TERM...HARTFIELD AVIATION...VINCENT

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