Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
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 030234 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1033 PM EDT TUE SEP 2 2014 .SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS CENTRAL NC ON WEDNESDAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM TUESDAY... CONVECTION HAS LARGELY DISSIPATED ACROSS THE AREA THIS EVENING WITH NOCTURNAL STABILIZATION TAKING HOLD. HOWEVER... AN APPROACHING LINE OF SHOWERS AND STORMS... CURRENTLY MOVING EAST-SOUTHEASTWARD THROUGH THE NC AND VA MOUNTAINS... IN ADVANCE OF A WEAK COLD FRONT IS EXPECTED TO APPROACH/POSSIBLY MOVE INTO PORTIONS OF THE AREA OVERNIGHT. WITH THE SPC MESOPAGE STILL SHOWING 1000-2000 J/KG OF MUCAPE ACROSS OUR NORTHWEST/NORTHERN PIEDMONT AND THE LATEST RAP AND HRRR SHOWING THE POTENTIAL FOR SOME OF THIS ACTIVITY TO MOVE INTO THIS AREA (NW/N PIEDMONT) WILL LEAVE A CHANCE OF SHOWERS AND STORMS IN THE FORECAST FOR THIS AREA. HOWEVER.. WITH THE LACK OF GOOD DEEP SHEAR AND DAYTIME HEATING THINK THIS LINE WILL CONTINUE TO SHOW A WEAKENING TREND AS IT MOVES INTO NW/N PORTIONS OF CENTRAL NC AROUND MIDNIGHT OR SHORTLY AFTER. THUS... WOULD EXPECT ANY OF THIS WEAKENING LINE TO REMAIN BELOW SEVERE LIMITS. WHERE HEAVY RAINFALL OCCURRED THIS PAST AFTERNOON-EVENING (GENERALLY ALONG AND SOUTH OF A LINE FROM ASHEBORO TO RALEIGH TO WILSON) AND SKIES PARTIALLY CLEAR OVERNIGHT... WE COULD SEE PATCHES OF FOG DEVELOP DURING THE PRE-DAWN HOURS OF WEDNESDAY. MIN TEMPS NEAR 70- LOWER 70S. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... AS OF 335 PM TUESDAY... SHEAR AXIS AND ATTENDANT SURFACE BOUNDARY WILL LIE ACROSS THE SOUTHERN COUNTIES OF CENTRAL NC. ISOLATED SHOWERS AND STORMS ALONG THIS FEATURE WEDNESDAY MORNING WILL GROW IN COVERAGE AS THE ATMOSPHERE HEATS UP...LEADING TO GREATER LOW LEVEL INSTABILITY. RELATIVELY WEAK STEERING FLOW SUGGEST THAT THE STORMS WILL BE SLOW MOVING. IF STORMS OCCUR OVER URBAN LOCATIONS...THIS MAY LEAD TO MINOR FLOODING OF STREETS AND POOR DRAINAGE AREAS. PLAN TO CAP POPS AT 50 PERCENT ACROSS THE SOUTH...DWINDLING TO 25-35 PERCENT ACROSS THE NW. MAX TEMPS WEDNESDAY DEPENDENT ON WHEN CONVECTIVE COVERAGE INCREASES AND WHETHER ANY PERIODS OF PARTIAL SUN OCCUR. BETTING ON SOME PARTIAL SUN INT HE LATE MORNING-EARLY AFTERNOON PRIOR TO CONVECTION INCREASING AFTER 2-3 PM. IF SKIES REMAIN OVERCAST OR CONVECTION BECOMES ACTIVE BY LUNCHTIME...MAX TEMPS MAY END UP BEING 5-6 DEGREES COOLER. CONTINUED WARM AND MUGGY WEDNESDAY NIGHT WITH SCATTERED CONVECTION SLOWLY DIMINISHING/DISSIPATING. MIN TEMPS NEAR 70-LOWER 70S. && .LONG TERM /THURSDAY THROUGH TUESDAY/... AS OF 255 PM TUESDAY... FOR THU/FRI: CONTINUED WARM/HUMID WITH DAILY SCATTERED SHOWERS AND STORMS. AT THE SURFACE... THE WEAK FRONTAL ZONE WILL LIKELY HAVE WASHED OUT BY THU MORNING... AND THE SURFACE HIGH CENTERED OFF THE SOUTHEAST COAST WILL INTRODUCE A MOIST CONFLUENT LOW LEVEL FLOW OFF THE ATLANTIC INTO NC. A POSITIVELY TILTED TROUGH WILL SHIFT FROM MT/DAKOTAS/SCENTRAL CANADA EARLY THU ACROSS ONT/QUE BY FRI NIGHT... PROPELLING A COLD FRONT THROUGH THE GREAT LAKES/MID MISS VALLEY. AS THE FLAT RIDGE HOLDS ACROSS THE SOUTHEAST/MIDSOUTH/GULF STATES HOWEVER... WE`LL STAY WITHIN AN ENVIRONMENT CHARACTERIZED BY WEAK SHEAR AND MODERATE INSTABILITY (TEMPERED BY WARM MID LEVELS). PW VALUES SHOULD STAY ABOVE NORMAL AT 1.7-1.9"... NOT UNEXPECTED GIVEN THE TROPICAL NATURE OF THE INCOMING AIR MASS... AND SUFFICIENT TO SUPPORT SCATTERED CONVECTION ALONG THE SEA BREEZE... DYING FRONTAL ZONE... OR ANY OTHER SUBTLE BOUNDARY. WILL RETAIN AFTERNOON AND EVENING STORM CHANCES BOTH DAYS... WITH TEMPS HOLDING ABOUT A CATEGORY ABOVE NORMAL AS THICKNESSES STAY AROUND 10 M ABOVE NORMAL. FOR SAT-TUE: STILL EXPECT A TRANSITION FROM THE WARM/HUMID WEATHER TO MORE SEASONABLE CONDITIONS LATE IN THE WEEKEND. THE INITIAL MID LEVEL TROUGH OVER ERN QUEBEC WILL CONTINUE SHIFTING EAST OVER THE MARITIMES... WHILE A STRONG SLUG OF STRONG VORTICITY EMANATING FROM A STRONG COLD VORTEX OVER THE BEAUFORT SEA WILL PUSH EASTWARD CLOSE ON ITS HEELS... CROSSING HUDSON BAY ON SUNDAY. THIS SHOULD PUSH THE SURFACE COLD FRONT TO JUST NW OF NC BY SUN... AND WELL INTO THE STATE BY EARLY MON. BOTH THE GFS AND ECMWF TRACK THEIR COOL PARENT HIGHS OVER THE ST LAWRENCE VALLEY/SRN QUEBEC MON/TUE... WITH THE COLD FRONT PUSHING TO ERN NC AND ACROSS NWRN SC. THIS MODEL AGREEMENT LEADS TO GROWING CONFIDENCE THAT THE PARENT HIGH WILL BE DENSE ENOUGH TO PUSH THIS COOLER AIR WELL INTO CENTRAL NC... ALTHOUGH IT MAY NOT HAPPEN UNTIL LATE SUN NIGHT INTO MON MORNING. WILL FOLLOW THIS TREND WITH TEMPS HOLDING ABOVE NORMAL SAT/SUN (BUT NOT AS WARM IN THE NORTH SUN DUE TO MORE CLOUDS) WITH HIGHS IN THE MID 80S TO NEAR 90... BUT THEN EXPECT TEMPS TO PLUNGE FOR MON/TUE WITH THICKNESSES DROPPING TO 10-20 M BELOW NORMAL... YIELDING HIGHS NEAR 80 TO LOWER 80S. REGARDING PRECIP CHANCES... WE`RE LIKELY TO SEE SCATTERED TO PERHAPS NUMEROUS SHOWERS AND STORMS LATE SAT THROUGH AT LEAST SUN NIGHT... BOTH ALONG THE PREFRONTAL PIEDMONT TROUGH AND AHEAD OF AND WITH THE FRONT ITSELF. SHOWER/STORM CHANCES ARE EXPECTED TO PEAK SUN AFTERNOON. WITH THE MID LEVEL TROUGH AXIS SWINGING THROUGH THE REGION MON... WE MAY SEE LINGERING CHANCES FOR RAIN ESPECIALLY SOUTH AND EAST. THE SURFACE RIDGE NOSING IN FROM THE NORTH LATE MON INTO TUE ACCOMPANIED BY LOWERING PW VALUES SHOULD MEAN MOSTLY DRY WEATHER TUE... AS THE MID LEVEL TROUGH AXIS LIFTS NE AWAY FROM THE REGION FOLLOWED BY WEAK MID LEVEL SHORTWAVE RIDGING OVER THE CAROLINAS. -GIH && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 110 PM TUESDAY... SCATTERED SHOWERS AND STORMS CONTINUE ACROSS THE AREA... BUT ARE NOT CURRENTLY AFFECTING ANY TERMINALS. A FEW STORMS ARE POSSIBLE THROUGH THE OVERNIGHT HOURS AS A WEAK BOUNDARY APPROACHES THE AREA FROM THE NORTHWEST. SUB-VFR CONDITIONS WITH LOW CLOUDS/FOG ARE POSSIBLE EARLY WEDNESDAY AT KFAY AND KRWI WHERE LOW LEVEL MOISTURE REMAINS HIGH... PARTICULARLY AT KFAY WHERE 1-2 INCHES OF RAIN FELL THIS EVENING. SCATTERED CONVECTION WILL BE MORE PROMINENT WEDNESDAY AFTERNOON- EVENING...MAINLY ACROSS THE SOUTHERN COUNTIES INCLUDING IN VICINITY OF THE KFAY TERMINAL. OTHERWISE VFR CONDITIONS ARE EXPECTED TYPICAL SUMMERTIME WEATHER CONDITIONS ANTICIPATED THURSDAY THROUGH SATURDAY WITH AREAS OF EARLY MORNING FOG AND LOW CLOUDS GIVING WAY TO VFR CONDITIONS ASIDE FROM SUB-VFR CONDITIONS IN VICINITY OF SCATTERED AFTERNOON-EARLY EVENING CONVECTION. ON SUNDAY...A FRONT WILL BE APPROACHING FROM THE NW. THIS WEATHER SYSTEM WILL LIKELY ENHANCE THE PROBABILITY OF CONVECTION ACROSS CENTRAL NC. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BSD/WSS NEAR TERM...BSD/WSS SHORT TERM...WSS LONG TERM...HARTFIELD AVIATION...SEC/WSS

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