Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 310248 RRA AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1047 PM EDT SAT AUG 30 2014 .SYNOPSIS...DEEP HIGH PRESSURE WILL EXTEND OVER THE REGION THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM SATURDAY... THE LATEST SURFACE ANALYSIS CONTINUED TO SHOW A SLACK GRADIENT OVER CENTRAL NORTH CAROLINA. RADAR SHOWED EARLIER SHOWERS HAD DIMINISHED...AS THE SEA BREEZE HAD MOVED NORTH AND WEAKENED WHILE VERY DRY MID-LEVEL AIR MOVED EAST ACROSS CENTRAL AND EASTERN NORTH CAROLINA ON WATER VAPOR IMAGERY. K INDICES SHOULD FALL INTO THE TEENS AS BUFR SOUNDINGS FROM THE GFS AND NAM ALONG WITH RAP SOUNDINGS SHOW AN OVERALL STABLE AIR MASS THEN. SOME OF THE TEMPERATURES ACROSS CENTRAL NORTH CAROLINA FELL QUICKLY DURING MID-EVENING...BUT WITH SOME THIN CIRRUS MOVING EAST FROM DEEP CONVECTION WELL UPSTREAM...ALONG WITH SURFACE DEW POINTS AROUND 70 TO THE LOWER 70S IN MOST LOCATIONS...TEMPERATURES ARE NOT EXPECTED TO CONTINUE THAT RAPID FALL. LOWS SHOULD MOSTLY BE WITHIN A DEGREE OR TWO OF 70. SOME LOW CLOUDS REMAIN POSSIBLE LATE TONIGHT PARTICULARLY AS NOTED ON NAM BUFR SOUNDINGS AND THE SREF PROBABILISTIC GUIDANCE...AND ALLUDED TO MORE ON THE GFS 18Z MOS GUIDANCE OUTPUT FROM ITS EARLIER...MORE OPTIMISTIC 12Z GUIDANCE. THE LATEST HRRR WRF WOULD SUGGEST A BETTER POTENTIAL FOR LOW CLOUDS LATE TONIGHT IN A NARROW AXIS ALONG AND WEST OF U.S. 1...WHERE SREF PROBABILITIES ARE A LITTLE HIGHER RELATIVE TO THE REST OF THE AREA AND CLOSER TO THE HIGHER 925MB WINDS. THOSE 925MB WINDS SEEM A LITTLE HIGH FOR FOG IN MOST PLACES...TO 20KT TOWARD THE TRIAD LATE TONIGHT...BUT THE LOWER VALUES OF 10 TO 15KT TOWARD INTERSTATE 95 ALONG WITH EXPECTED DEW POINTS IN THE LOWER 70S COULD ALLOW A LITTLE MORE NOTICEABLE FOG IN PATCHES TOWARD THERE LATE. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 230 PM SATURDAY... A SHORT WAVE TROUGH OVER THE MS RIVER VALLEY TO START THE DAY WILL LIFT TO THE NORTHEAST INTO THE OH VALLEY THROUGH SUNDAY NIGHT. HOWEVER...ITS ASSOCIATED ENERGY AND DEEP MOISTURE PLUME (EMANATING FROM THE GULF) WILL LARGELY REMAIN WEST AND NORTH OF CENTRAL NC. IN ADDITION...THE SUBTROPICAL RIDGE CENTERED OVER THE SOUTHEAST COAST SHOULD ALSO HELP KEEP THE BETTER RAIN CHANCES WEST OF THE AREA. THEREFORE...WILL CONTINUE THE FORECAST THINKING OF ONLY ISOLATED TO WIDELY SCATTERED SHOWERS/STORMS...WITH THE BEST CHANCES ACROSS THE WEST DUE TO THE PROXIMITY OF THE ABOVE FEATURES. TEMPS WILL CONTINUE TO BE ABOVE NORMAL...WITH HIGHS GENERALLY IN THE LOWER 90S AND OVERNIGHT LOWS AROUND 70 DEGREES. && .LONG TERM /MONDAY THROUGH SATURDAY/... AS OF 200 PM SATURDAY... WITH ROUGHLY 3 WEEKS OF SUMMER REMAINING (AUTUMN EQUINOX IS SEPT 23)...THE WESTWARD EXPANSION OF THE SUBTROPICAL RIDGE ACROSS MUCH OF THE SOUTHERN CONUS...WITH THE MAIN BELT OF WESTERLIES RETREATING NORTHWARD ALONG THE US-CANADA BORDER WILL RESULT IN THE FIRST PROLONGED PERIOD OF SUMMERTIME HEAT AND CONVECTIVE RAIN CHANCES THAT CENTRAL NC HAS SEEN THIS SEASON. AFTERNOON THICKNESSES ARE PROGGED TO RUN 25 TO 30 METERS ABOVE CLIMATOLOGY...WHICH SHOULD SUPPORT DAYTIME HIGHS RANGING FROM 90 TO 95F WITH LOWS IN THE UPPER 68 TO 74F. A LOW AMPLITUDE TROUGH MOVING EASTWARD ACROSS THE NORTHEAST AND MID- ATLANTIC STATES WILL TEMPORARILY FLATTEN THE UPPER ANTICYCLONE LONG ENOUGH TO ALLOW A WEAK SURFACE FRONT TO APPROACH NC FROM THE NORTH...BUT RECENT MODEL TRENDS OVER THE LAST COUPLE OF DAYS REALLY WASHES OUT THE FRONT TO OUR NORTH DURING THE LATE WEDNESDAY/THURSDAY PERIOD. AS SUCH...GRIDDED DATABASE WILL CONTINUE TO EXHIBIT DIURNALLY DRIVEN CONVECTION ISOLATED TO WIDELY SCATTERED STORMS EACH AFTERNOON...FIRING WITHIN A MODERATELY UNSTABLE AIRMASS ALONG A LEE SIDE SURFACE TROUGH. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... AS OF 751 PM SATURDAY... VFR CONDITIONS WILL CONTINUE THROUGH THE EVENING. LOW LEVEL MOISTURE REMAINS HIGH ACROSS THE AREA WITH LIGHT SURFACE WINDS... AND IFR CONDITIONS WITH STRATUS... AND POSSIBLY SOME PATCHY FOG.... ARE EXPECTED TO DEVELOP IN THE EARLY MORNING HOURS SUNDAY AT KRDU...KRWI...AND KFAY... WHERE DEWPOINTS ARE HIGHEST. MVFR CONDITIONS ARE POSSIBLE AT KGSO AND KINT. CONDITIONS WILL RETURN TO VFR AFTER 12Z SUNDAY... WITH A FEW SHOWERS/THUNDERSTORMS POSSIBLE IN THE AFTERNOON. OUTLOOK...A SUMMERTIME PATTERN WILL PERSIST THROUGH EARLY/MID NEXT WEEK...WITH ISOLATED TO SCATTERED AFTERNOON/EVENING CONVECTION AND A POTENTIAL FOR EARLY MORNING FOG/STRATUS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GIH NEAR TERM...DJF SHORT TERM...KRD LONG TERM...CBL AVIATION...SEC/KRD

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