Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KRAH 260657 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 257 AM EDT TUE AUG 26 2014 .SYNOPSIS...HIGH PRESSURE WILL EXTEND SOUTHWARD INTO THE REGION THROUGH WEDNESDAY. A WEAK BACK DOOR FRONT WILL APPROACH FROM THE NORTH EARLY THURSDAY. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 250 AM TUESDAY... TODAY AND TONIGHT: SURFACE HIGH PRESSURE CENTERED JUST TO THE NORTH OF CENTRAL NC CONTINUES TO EXTEND SOUTHWARD INTO THE AREA THIS MORNING... WHILE THE MID LEVEL RIGE AXIS IS CONTINUING TO SLOWLY SINK SOUTHWARD AND EVENTUALLY ACROSS CENTRAL NC LATER TODAY. THIS WILL LEAD TO ANOTHER DRY DAY ACROSS THE REGION. THE LATEST NAM AND GFS CONTINUE TO SHOW A LITTLE BIT DRIER AIR WORKING INTO THE AREA TODAY IN THE 925-850 MB LAYER. CURRENTLY IR SATELLITE IMAGERY SHOWS A SHRINKING AREA OF CLOUD COVER TRAPPED BELOW THE PROMINENT SUBSIDENCE INVERSION AT AROUND 850 MB. THE AREA OF CLOUD COVER IS EXPECTED TO GENERALLY DISSIPATE OVER THE NEXT SEVERAL HOURS. STILL THINK WE WILL SEE AT LEAST SOME STRATOCUMULUS DEVELOP THIS MORNING IN THE MID MORNING/EARLY AFTERNOON TIME FRAME.... ALTHOUGH NOT AS MUCH AS YESTERDAY. THUS... WOULD NOT EXPECT THE CLOUD COVER TO HAVE AS BIG OF IMPACT ON HIGH TEMPS TODAY. GIVEN THE EXPECTED INCREASE IN AFTERNOON LOW LEVEL THICKNESS VALUES OF AROUND 5-10 METERS... WOULD EXPECT HIGH TEMPS WILL BE 2-5 DEGREES WARMER TODAY. THIS YIELDS TEMPS GENERALLY IN THE MID 80S ACROSS THE AREA FOR TODAY. OUTSIDE OF POSSIBLY SOME LINGERING MOISTURE/CLOUDS TRAPPED UNDER THE SUBSIDENCE INVERSION AGAIN EARLY TONIGHT (LESS THAN THIS PAST EVENING/CURRENTLY)... THINK SKIES SHOULD BECOME MOSTLY CLEAR/CLEAR... WITH A LIGHT NORTHERLY BREEZE. WITH DEWPOINTS AGAIN EXPECTED TO FALL INTO THE 50S AND LOW 60S OVERNIGHT.... THINK LOW TEMPS WILL GENERALLY BE IN THE UPPER 50S TO LOWER 60S. WEDNESDAY: HURRICANE CRISTOBAL IS EXPECTED TO LIFT NORTHWARD AND PASS AROUND 500 MILES TO THE EAST OF THE NC COAST ON WEDNESDAY. THUS... EXPECT NO IMPACT FROM THE PASSING TROPICAL SYSTEM FOR CENTRAL NC... EXCEPT A POSSIBLE ENHANCED OF THE TEMPS ON THE WARM SIDE OVER OUR AREA. AFTERNOON LOW LEVEL THICKNESS VALUES ARE EXPECTED TO INCREASE SOME 15 TO 25 METERS ON WEDNESDAY... VS TODAY. THUS... HAVE RAISED HIGH TEMPS ON WEDNESDAY TO AROUND 90/LOWER 90S... AND WE COULD EVEN SEE A FEW MID 90S. OTHERWISE DRY WEATHER IS EXPECTED AS VERY STABLE CONDITIONS PERSIST OVER THE AREA. && .SHORT TERM /WEDNESDAY NIGHT/... AS OF 230 PM MONDAY... FOR WED/WED NIGHT: 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 /06Z TUESDAY THROUGH SATURDAY/... AS OF 150 AM TUESDAY... 24-HR TAF PERIOD: VFR CONDITIONS WILL GENERALLY CONTINUE AND A LIGHT NORTH TO NORTHEASTERLY BREEZE WILL RULE THROUGH THE TAF PERIOD AS DRY HIGH PRESSURE EXTENDS SOUTHWARD INTO THE CAROLINAS. A FEW LINGERING VFR CIGS NEAR KGSO/KINT/FAY ARE EXPECTED TO DISSIPATE EARLY THIS MORNING. HOWEVER... WE COULD SEE SOME PATCHY SUB-VFR FOG ACROSS THE AREA THIS MORNING IN THE PRE-DAWN HOURS. THE BEST CHANCE OF THIS WILL BE AT KRWI. THUS... HAVE ADDED A TEMPO GROUP AT KRWI FOR SOME PRE-DAWN SUB-VFR VISBYS. HAVE LIMITED THE RESTRICTIONS TO MVFR GIVEN CONFIDENCE IS FAIRLY LOW IN HOW MUCH PATCHY SUB-VFR VISBYS WE WILL SEE THIS MORNING. GIVEN A BIT LESS IN THE WAY OF LOW LEVEL MOISTURE TODAY... DO NOT EXPECT AS MUCH IN THE WAY OF CLOUD COVER TO DEVELOP WITH SURFACE HEATING AFTER SUNRISE THIS MORNING. WE COULD SEE SOME SCATTERED CLOUDS DEVELOP IN THE 2-3.5 KFT RANGE DURING THE MID MORNING... BUT CONFIDENCE IN ANY SUB-VFR BROKEN/OVERCAST CLOUD COVER IS TOO LOW TO INCLUDE ANY MENTION IN THE TAFS AT THIS TIME. LOOKING AHEAD: VFR CONDITIONS WILL PREVAIL THROUGH MID-WEEK AS DRY HIGH PRESSURE PERSISTS OVER THE CAROLINAS... OUTSIDE OF A SMALL CHANCE AGAIN FOR SOME PATCHY SUB-VFR FOG IN THE PRE-DAWN HOURS OF WEDNESDAY. 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. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...BSD SHORT TERM...HARTFIELD LONG TERM...HARTFIELD AVIATION...BSD/VINCENT

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.