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 250526 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 125 PM EDT FRI JUL 25 2014 .SYNOPSIS...A COLD FRONT PUSHING SOUTHEAST THROUGH THE REGION EARLY THIS MORNING WILL WEAKEN AND STALL NEAR THE SOUTH CAROLINA BORDER LATER TODAY...AS WEAK HIGH PRESSURE BUILDS IN FROM THE NORTH. THIS FRONT WILL DISSIPATE OVER THE WEEKEND AS SOUTHWEST FLOW RETURNS. A STRONGER COLD FRONT WILL MOVE THROUGH THE REGION EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 PM THURSDAY... A S/W CROSSING THE CENTRAL APPALACHIANS WILL CONTINUE TO LIFT E-NE INTO THE NORTHERN MID ATLANTIC OVERNIGHT. THE SURFACE FRONT ASSOCIATED WITH THE S/W WAS DRIFTING SOUTHWARD ACROSS VA AT 01Z. A PRE-FRONTAL TROUGH AHEAD OF THE SURFACE FRONT AIDED TO TRIGGER SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON ACROSS CENTRAL NC. BY MID-EVENING..THE LINE OF CONVECTION HAD DRIFTED SOUTHWARD INTO THE SOUTHERN COASTAL PLAIN AND SANDHILLS. SHOWERS WITH A FEW ISOLATED THUNDERSTORMS WILL PERSIST WELL INTO THE NIGHT ACROSS ROUGHLY THE SE HALF OF CENTRAL NC AS THE PRE-FRONTAL TROUGH STALLS AND WAITS FOR THE APPROACHING SFC FRONT. AN ISOLATED SHOWER OR THUNDERSTORM WILL BE POSSIBLE OVERNIGHT ACROSS THE NORTH AS THE SFC FRONT CROSSES THE REGION. BY FRIDAY MORNING...SFC FRONT SHOULD BLEND WITH THE SFC TROUGH THEN CONTINUE TO PUSH SOUTH AND EAST AS SFC HIGH PRESSURE BUILDS INTO THE PIEDMONT. MIN TEMPS OVERNIGHT SHOULD RANGE FROM THE LOWER 70S SOUTH TO THE MID- UPPER 60S NORTH. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 305 PM THURSDAY... FRIDAY AND FRIDAY NIGHT....THE MAIN UPPER TROUGH AXIS WILL MOVE EAST OF THE AREA BY FRIDAY MORNING...WHILE THE ASSOCIATED RELATIVELY WEAK COLD FRONT SLIPS SOUTH AND STALLS NEAR THE NC/SC BORDER. HIGH PRESSURE WILL BUILD QUICKLY ACROSS VA DURING THE DAY...WITH DRIER MID-LEVEL AIR OVER MOST OF CENTRAL NC. THE AIRMASS DOESNT CHANGE MUCH BEHIND THE FRONT...WITH DEWPOINTS ONLY DROPPING INTO THE MID 60S TO THE NORTHWEST AND HOVERING NEAR 70S IN THE SOUTH. WEAK INSTABILITY AND LEVEL CONVERGENCE IN THE VICINITY OF WHAT IS LEFT OF THE FRONT MAY PRODUCE SOME VERY ISOLATED CONVECTION NEAR THE SC BORDER. HIGHS WILL BE IN THE MID 80S. WEAK HIGH PRESSURE WILL BE OFF THE VA COAST BY FRIDAY NIGHT...AND A LIGHT SOUTHEASTERLY RETURN FLOW MAY PRODUCE SOME FOG AND LOW CLOUDS SATURDAY MORNING...SHOWN MOST AGGRESSIVELY BY THE NAM. LOWS IN THE MID/UPPER 60S. SATURDAY AND SATURDAY NIGHT...A WEAK UPPER DISTURBANCE...POSSIBLY EMANATING FROM CONVECTION NORTH OF THE SOUTHERN PLAINS RIDGE...WILL SWING ACROSS THE AREA ON SATURDAY. CURRENTLY...MODELS SHOW THE WAVE DEAMPLIFYING AS IT CROSSES THE MOUNTAINS...AND THE EARLY DAY TIMING WOULD ALSO BE UNFAVORABLE FOR CONVECTIVE INITIATION. MOST OF CENTRAL NC WILL REMAIN DRY...WITH THE EXCEPTION BEING THE FAR SOUTHEAST CWA WHERE THE SEABREEZE MAY MAKE A RUN DURING THE AFTERNOON. WEST-SOUTHWESTERLY LOW-LEVEL FLOW WILL PROMOTE DEEPER MIXING AND A WARMER DAY WITH HIGHS LIKELY IN THE LOWER 90S. LOWS SAT NIGHT WILL BE WARMER AS WELL IN THE LOWER 70S. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 305 PM THURSDAY... SUNDAY THROUGH MONDAY NIGHT... A STRONG SHORTWAVE MOVING SOUTHEAST OUT OF THE CANADIAN ROCKIES ON SUNDAY WILL BEGIN THE AMPLIFICATION OF THE LONGWAVE PATTERN HEADING INTO NEXT WEEK. CONVECTION PASSING TO OUR NORTH ACROSS VA MAY BLEED SOUTH INTO MAINLY THE NORTHERN PORTIONS OF THE AREA...PARTICULARLY SUNDAY EVENING BASED ON CURRENT PROGS. HOWEVER THE MAIN FORCING TO IMPACT CENTRAL NC WILL COME MONDAY WHEN MODELS SHOW ADDITIONAL ENERGY...ACCOMPANIED BY STRONG HEIGHT FALLS AND A BELT OF ENHANCED WESTERLIES...SWINGING ACROSS THE AREA. GIVEN THAT TEMPS ARE EXPECTED TO BE WELL INTO THE MID 90S ON SUNDAY AND AT LEAST THE LOWER 90S ON MONDAY...INSTABILITY SHOULD BE FAVORABLE AHEAD OF THE FRONT. WHILE THERE IS STILL SOME UNCERTAINTY AS TO HOW MUCH OVERLAP THERE WILL BE BETWEEN THE BEST INSTABILITY AND STRONGEST SHEAR...THE SETUP LOOKS PRETTY GOOD FOR SEVERE WEATHER AT DAY 5 IN LATE JULY. TUESDAY THROUGH THURSDAY... MEDIUM RANGE ENSEMBLES SHOW AN UNSEASONABLY DEEP UPPER TROUGH DEVELOPING OVER THE EASTERN US BY MID WEEK WITH AN UPPER LOW CENTERED JUST SOUTH OF THE HUDSON BAY. GIVEN THAT BOTH THE GFS AND ECMWF SHOW THE SYNOPTIC FRONT REACHING THE GULF OF MEXICO... CONFIDENCE IS HIGH THAT TEMPS WILL BE BELOW NORMAL MUCH OF NEXT WEEK. LOW-LEVEL THICKNESSES ARE PROGGED TO DIP BELOW 1390M...WHICH SUGGESTS HIGHS IN THE LOW/MID 90S AND LOWS IN THE LOW/MID60S... POSSIBLY TOUCHING THE UPPER 50S IN THE COOLEST SPOTS. THE AIRMASS CHANGE WILL ALSO BRING LOWER HUMIDITY...AND WITH DEWPOINTS DROPPING INTO THE 50S THE CHANCES OF SHOWERS OR STORMS WILL BE RELATIVELY LOW UNTIL RETURN FLOW DEVELOPS LATER IN THE WEEK. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 125 AM FRIDAY... PROBLEMATIC AVIATION CONDITIONS EARLY THIS MORNING... AS SCATTERED TO BROKEN CLOUDS BASED BETWEEN 600 AND 1400 FT AGL MEANDER ABOUT CENTRAL NC. WITH THESE LOW CIGS EXPECTED TO COME AND GO THROUGH DAYBREAK... THE TIMING OF MVFR/IFR CIGS IS MADE DIFFICULT. EXPECT CIGS TO VARY BETWEEN VFR AND MVFR/IFR THROUGH DAYBREAK AT ALL SITES AS THESE CLOUDS DRIFT OVER THE REGION... WITH MVFR/IFR DOMINATING. MVFR CIGS ARE EXPECTED THROUGH THE MORNING AS THESE CLOUDS LIFT SLOWLY... WITH CIGS NOT REACHING VFR UNTIL CLOSE TO 18Z... AND EVEN AFTER THIS TIME AT FAY... CLOSE TO WHERE THE COLD FRONT IS EXPECTED TO HAVE PUSHED BY AFTERNOON. A FEW SHOWERS AND ISOLD STORMS WILL BE RESTRICTED TO NEAR FAY THIS AFTERNOON. VFR CIGS ARE EXPECTED TO PERSIST THEN FROM MID AFTERNOON THROUGH THE END OF THE TAF PERIOD. AS THE FRONT SETTLES SOUTH OF ALL TAF SITES THIS MORNING... EXPECT A LIGHT BREEZE FROM THE NORTH TO DOMINATE THROUGH THE DAY. LOOKING BEYOND 06Z EARLY SAT MORNING... EXPECT CONTINUED VFR CIGS THROUGH DAYBREAK SAT... ALTHOUGH POCKETS OF IFR FOG ARE POSSIBLE 09Z- 13Z SAT MORNING... ESPECIALLY AT RWI/FAY. OTHERWISE... VFR CONDITIONS ARE LIKELY TO DOMINATE THROUGH THE WEEKEND WITH HIGH PRESSURE BUILDING IN... FOLLOWED BY A RESUMPTION OF SOUTHWEST FLOW AND PIEDMONT TROUGH LATE IN THE WEEKEND. A COLD FRONT WILL APPROACH FROM THE NW EARLY NEXT WORK WEEK... BRINGING THE POTENTIAL FOR SUB- VFR SHOWERS/STORMS... PARTICULARLY MONDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...WSS SHORT TERM...BLS LONG TERM...BLS AVIATION...HARTFIELD

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