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 030002 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 802 PM EDT THU JUL 2 2015 .SYNOPSIS...A COLD FRONT WILL APPROACH FROM THE NORTH..AND STALL OVER THE MIDDLE ATLANTIC STATES TONIGHT THROUGH THE HOLIDAY WEEKEND. MEANWHILE A SERIES OF UPPER LEVEL DISTURBANCES WILL CROSS OVERHEAD...BRINGING PERIODS OF SHOWERS AND THUNDERSTORMS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 PM THURSDAY... LATE AFTERNOON THROUGH TONIGHT... LOW LEVEL ATMOSPHERE HAS BECOME SLIGHT-MODERATELY UNSTABLE AT MID AFTERNOON THANKS TO PARTLY SUNNY SKIES. AS OF 18Z...ISOLATED SHOWERS HAVE DEVELOPED ALONG A SLOW MOVING 925-850MB TROUGH...ORIENTATED SW-NE ACROSS THE NORTHERN PIEDMONT. MEANWHILE A MID LEVEL S/W WAS LIFTING E-NE OUT OF THE TN VALLEY INTO THE CENTRAL/SOUTHERN APPALACHIANS. AS THIS MID LEVEL FEATURE GETS CLOSER TO CENTRAL NC...EXPECT CONVECTION TO GROW IN STRENGTH AND COVERAGE WITH THE GREATEST COVERAGE EXPECTED ACROSS THE NORTHERN PIEDMONT IN VICINITY OF THE LOW LEVEL TROUGH. WESTERLY STEERING FLOW WILL TAKE THIS CONVECTION INTO THE COASTAL PLAIN BY SUNSET. SEVERE PARAMETERS NOT OVERLY IMPRESSIVE AT 18Z THOUGH BULK SHEAR VALUES ARE 5-10KTS STRONGER COMPARED TO THE GFS MODEL PROJECTIONS. WITH SHEAR VALUES NEAR 30KTS...COULD SEE STORMS EVOLVE INTO BROKEN BANDS WHICH MAY LEAD TO A FEW INSTANCES OF LOCALLY DAMAGING WINDS. WHILE BULK OF CONVECTION WILL DIMINISH AROUND MIDNIGHT...A MOIST AND SLIGHTLY UNSTABLE AIR MASS COUPLED WITH WEAK PERTURBATIONS CROSSING OVERHEAD WILL CAUSE A FEW SHOWERS TO PERSIST WELL INTO THE OVERNIGHT HOURS. MIN TEMPS UPPER 60S-LOWER 70S. && .SHORT TERM /FRIDAY AND FRIDAY NIGHT/... AS OF 300 PM THURSDAY... FRIDAY...WATER VAPOR IMAGERY THIS AFTERNOON DEPICTS A WELL DEFINED CONVECTIVELY INDUCE VORT MAX MOVING SEWD ON THE BACKSIDE OF THE BAGGY UPPER LEVEL TROUGH. MODEL GUIDANCE HAS A FAIRLY GOOD HANDLE ON THIS FEATURE. THIS SYSTEM PROJECTED TO ROUND THE BASE OF THE TROUGH LATE TONIGHT/EARLY FRI THEN CROSS THE CAROLINAS LATER FRIDAY. BASED ON CURRENT TIMING...SHOULD SEE SCATTERED CONVECTION DEVELOP A FEW HOURS EARLIER THAN NORMAL...POSSIBLY AS EARLY AS 10-11 AM...WITH THE MAJORITY OF THE CONVECTION OCCURRING BETWEEN NOON AND 8 PM. THE LOW LEVEL ATMOSPHERE EXPECTED TO BE SLIGHT-MODERATELY UNSTABLE ALONG WITH EFFECTIVE BULK SHEAR VALUES APPROACHING 30KTS... SUPPORTIVE OF ORGANIZED CONVECTION. WIND PROFILE FAIRLY UNIDIRECTIONAL (SW) SO EXPECT CONVECTION TO EVOLVE INTO BROKEN BANDS...PRODUCING STRONG/LOCALLY DAMAGING WINDS. MAX TEMPS FRIDAY DEPENDENT ON WHEN CONVECTION DEVELOPS AND EXTENT OF CLOUD COVER OVERHEAD. EXPECT MORE CLOUDS THAN SUN NORTH AS WELL AS MORE CONVECTION ACROSS THE NORTH SO SHOULD SEE A TEMP RANGE OF LOW- MID 80S NORTH TO UPPER 80S/AROUND 90 SOUTH. EARLIER INITIATION OF CONVECTION WILL LIKELY HAVE AN EFFECT ON MAX TEMPS (2-3 DEGREES COOLER). CURRENTLY APPEARS BULK OF ENERGY ASSOCIATED WITH THE VORT MAX EXITS OUR REGION BY EARLY EVENING. THIS SUGGEST THAT CONVECTION SHOULD SLOWLY WANE/DIMINISH BETWEEN 7-10 PM ACROSS THE REGION. SIMILAR TO TONIGHT...PRESENCE OF OF A MOIST AIR MASS...A STALLED LOW LEVEL TROUGH AND PERTURBATIONS ALOFT SUGGEST A FEW SHOWERS MAY LINGER INTO THE OVERNIGHT HOURS. MIN TEMPS UPPER 60S-LOWER 70S. && .LONG TERM /SATURDAY THROUGH THURSDAY/... AS OF 245 PM FRIDAY... THE GENERAL OVERALL PATTERN WILL BE DOMINATED BY GENERAL TROUGHINESS IN THE UPPER LEVELS OVER THE EASTERN U.S. WITH A FEW SHORTWAVE DISTURBANCES PROGRESSING THROUGH THE AREA. AT THE SURFACE...A STALLED BOUNDARY WILL LINGER IN THE VICINITY OF CENTRAL NC...WITH GENERALLY LOW PRESSURE OVER THE AREA THROUGH THE PERIOD. WHAT THIS MEANS WEATHER-WISE IS THE TYPICAL SUMMERTIME HIGHER CHANCES FOR CONVECTION DURING THE DAY/EVENING HOURS AND LESS OVERNIGHT/EARLY MORNING. HOWEVER...SMALL VARIATIONS IN THIS PATTERN WILL HAVE BIG IMPACTS ON THE CHANCES...TIMING...AND LOCATION OF CONVECTION...THUS CONFIDENCE IS STILL NOT TERRIBLY HIGH IN THAT RESPECT. AS OF THE LATEST MODEL RUNS...HIGHEST PRECIP CHANCES WILL BE ON SUNDAY. TEMPERATURE-WISE: HIGHS WILL GENERALLY BE IN THE MID 80S TO LOW 90S THROUGH THE PERIOD...WITH OVERNIGHT LOWS STEADY IN THE UPPER 60S TO LOW 70S. FORECAST SOUNDINGS CONTINUE TO INDICATE PW`S IN THE 1.5-2 INCH RANGE THROUGH THE PERIOD...THUS THERE IS STILL THE THREAT OF SOME MINOR FLOODING RESULTING FROM DEVELOPING STORMS. AS OF THIS AFTERNOON...CENTRAL NC IS UNDER JUST A GENERAL THUNDER THREAT FOR SATURDAY. A SHORTWAVE TRAVERSING THE AREA ON MONDAY MAY BRING THE BEST CHANCE FOR STRONG STORMS...WITH GFS BUFR SOUNDINGS INDICATING MODEST INSTABILITY...BUT WEAK SHEAR. GIVEN HOW THINGS CAN CHANGE BETWEEN NOW AND THEN...WILL LEAVE MENTION OUT OF HWO FOR NOW. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... AS OF 800 PM THURSDAY... 24 HOUR TAF PERIOD: CONVECTION IS BEGINNING TO WANE THIS HOUR BUT SHOWERS AND STORMS WILL STILL REMAIN IN THE VICINITY OF KRWI FOR THE NEXT COUPLE OF HOURS. ALL OTHER SITES MAY SEE A LINGERING SHOWER BUT OTHERWISE MOSTLY VFR CONDITIONS. AS WITH THE PAST COUPLE OF NIGHTS...THERE EXISTS A CHANCE OF FOG OR LOW STRATUS NEAR DAYBREAK BUT GUIDANCE IS NOT PICKING IT UP PARTICULARLY WELL AND CONFIDENCE IS ONLY MEDIUM AT THIS TIME. TRIAD SITES AND KRWI WHICH IS GETTING SOME EXTENDED PRECIPITATION MAY BE THE BEST LOCATIONS FOR FOG/LOW STRATUS OVERNIGHT. EXPECT ANOTHER ROUND OF CONVECTION TOMORROW AFTERNOON BUT OUTSIDE OF CONVECTION...VFR CONDITIONS SHOULD PREVAIL. LONG TERM: A PROLONGED PERIOD OF UNSETTLED WEATHER WILL LEAD TO PERIODS OF ADVERSE AVIATION CONDITIONS FOR THE NEXT SEVERAL DAYS. && ..RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...WSS SHORT TERM...WSS LONG TERM...RAH AVIATION...ELLIS

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