Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 291914 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 310 PM EDT TUE JUL 29 2014 .SYNOPSIS...CANADIAN HIGH PRESSURE WILL EXTEND INTO THE CAROLINAS AND MIDDLE ATLANTIC THROUGH MID-WEEK. MOISTURE WILL BE ON THE INCREASE THURSDAY AND FRIDAY AS A COASTAL FRONT SPREADS INLAND. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/... AS OF 230 PM TUESDAY... SCATTERED TO BROKEN STRATOCUMULUS IS NOW EXTENDING INTO THE WESTERN AREAS OF THE CWA. THIS MAY KEEP MAXIMUM TEMPERATURES FROM BREAKING 80 DEGREES IN THE WESTERN PIEDMONT AND EXTREME SOUTHWEST. OTHERWISE TEMPERATURE FORECAST APPEARS TO BE ON TRACK WITH HIGHS IN THE UPPER LOW TO MID 80S NORTH TO SOUTH. OVERNIGHT WILL BE DRY WITH LOWS IN THE UPPER 50S TO LOWER 60S. WHILE MODEL GUIDANCE APPEARS TO HINT AT SOME MVFR VISIBILITIES NEAR DAYBREAK IN THE EAST...FORECAST SOUNDINGS APPEAR TOO DRY IN THE LOW LEVELS FOR THIS TO HAPPEN. POTENTIAL CLOUD COVER OVERNIGHT WOULD ALSO HELP TO LESSEN ANY FOG THREAT. WEDNESDAY WILL HAVE CONTINUED SUBSIDENCE KEEPING DRY CONDITIONS IN PLACE WITH A SLIGHT WARMING TREND BUT STILL IN THE LOW TO MID 80S FOR HIGHS WITH UPPER 50S TO LOW 60S ONCE AGAIN FOR MINIMUM TEMPERATURES. SCATTERED TO BROKEN CLOUD COVER IN THE 5-8 KFT RANGE WILL HAVE THE HEAVIEST CONCENTRATION IN EASTERN AREAS OF THE CWA WHICH MAY HELP KEEP MAX TEMPS DOWN A DEGREE OR TWO FROM FORECASTED HIGHS. .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... AS OF 310 PM TUESDAY... DEEP UPPER TROUGHING OVER THE EASTERN HALF OF THE US WILL CONTINUE THURSDAY...THOUGH WITH A BRIEF RELAXATION AND HEIGHT RISES ALOFT BETWEEN A SHORTWAVE LIFTING OFF TO THE NORTHEAST AND ENERGY DIVING THROUGH THE PLAINS STATES. THICKNESSES RISE ABOUT 10M OVER WEDNESDAY...STARTING OUT AT 1395M THURSDAY MORNING...WHICH SHOULD YIELD 83-87 UNDER MAINLY PARTLY CLOUDY SKIES. DEWPOINTS STILL IN THE 50S AND LOWER 60S WILL LIMIT CAPE TO A COUPLE HUNDRED J/KG OR LESS...THOUGH A LITTLE BETTER MOISTURE AT THE TOP OF THE BOUNDARY LAYER MAY HELP ENHANCE CLOUD COVER ACROSS THE SOUTHERN PORTIONS OF THE AREA...ESPECIALLY ALONG THE SEABREEZE. ANY SHOWERS AND STORMS SHOULD REMAIN SOUTH OF THE AREA. CLOUDS...ESPECIALLY MID AND HIGH CLOUDS WILL CONTINUE TO INCREASE THURSDAY NIGHT AS A SHORTWAVE DIVES THROUGH THE DEEP SOUTH. LOWS WILL BE MOSTLY IN THE MID 60S. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 310 PM TUESDAY... THE FRIDAY THROUGH TUESDAY PERIOD IS ONE OF MIXED CONFIDENCE. MODELS ARE IN GOOD AGREEMENT THAT THE MEAN UPPER TROUGH AXIS WILL REMAIN WEST OF THE APPALACHIANS...PLACING NC IN SOUTHWESTERLY FLOW ALOFT AND IN THE RIGHT ENTRANCE REGION OF AN UPPER JET ALONG THE SPINE OF THE MOUNTAINS. AN INVERTED COASTAL TROUGH WILL SLOWLY MEANDER WESTWARD OVER THE WEEKEND AND THEN LIKELY WASH OUT BY EARLY NEXT WEEK AS THE TROUGH WEAKENS AND THE WESTERN ATLANTIC RIDGE BUILDS WESTWARD. THIS WILL CAUSE PW TO CONTINUE TO INCREASE TO UPWARDS OF TWO INCHES BY SUNDAY. WHILE THIS POINTS TOWARD A WET WEEKEND...CONFIDENCE IS LOW WHEN IT COMES TO BEST TIME FRAME FOR PRECIP. ON FRIDAY...MODELS ARE SHOWING A DISTURBANCE EMANATING FROM CONVECTION OVER THE HIGH PLAINS THAT SWEEPS AROUND THE BASE OF THE TROUGH AND THEN LIFTS ACROSS OUR REGION. ITS HARD TO PUT MUCH FAITH IN SUCH A FEATURE THREE DAYS OUT...BUT ALL MODELS HAVE SHOWN AN INCREASE IN QPF FOR FRIDAY...SO HAVE INCREASED POPS INTO THE 40-50 RANGE. HOWEVER...BEYOND FRIDAY THERE IS VERY LITTLE TO KEY ON FOR FORCING OTHER THAN THE AFOREMENTIONED JET AND WEAKENING COASTAL TROUGH. THUS...WILL HAVE CHANCE POPS IN EACH DAY BE KEEP THEM BELOW 50 PERCENT UNTIL IT BECOMES MORE APPARENT WHICH DAY WILL BE FAVORED. THUNDER POTENTIAL LOOKS LIMITED FRIDAY AND SATURDAY GIVEN LIMITED INSTABILITY WITH WEAK LAPSE RATES ALOFT AND RELATIVELY COOL DAYTIME TEMPS IN THE UPPER 70S AND LOWER 80S. A WARMING TREND SHOULD ENDUE BY SUNDAY AND MONDAY AS THE UPPER RIDGE AND BERMUDA HIGH STRENGTHEN TO OUR EAST. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 110 PM TUESDAY... 24 HOUR TAF PERIOD: MODERATE TO HIGH CONFIDENCE OF VFR CONDITIONS THROUGH THE END OF THE TAF PERIOD. THE ONLY CAVEAT TO THAT IS MODEL GUIDANCE SHOWING SOME SMALL CHANCE FOR SOME MVFR VISIBILITIES IN THE EAST CLOSER TO SUNRISE. A LOOK AT THE FORECAST SOUNDINGS DOES NOT MAKE THIS SEEM LIKELY AND SO WILL LEAVE IT OUT OF THE TAFS FOR NOW BUT THIS IS A POSSIBILITY BETWEEN 9Z AND 12Z AT KRDU...KFAY...AND KRWI. OTHERWISE LIGHT AND VARIABLE WINDS WITH A PREDOMINANTLY NORTH OR NORTHEASTERLY DIRECTION SHOULD PREVAIL THROUGH THE TAF PERIOD. THERE IS A CHANCE THAT SOME SOUTHWESTERLY WINDS WILL BEGIN IN THE SOUTH AND EAST AT THE VERY END OF THE TAF PERIOD. LONG TERM: A FRONT THAT HAS STALLED OFFSHORE MAY RETROGRADE BACK OVER EASTERN NC BY THE END OF THE WEEK...POTENTIALLY RESULTING IN PERIODS OF SUB-VFR CONDITIONS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...ELLIS NEAR TERM...ELLIS SHORT TERM...BLS LONG TERM...BLS AVIATION...ELLIS

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