Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 301045 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 645 AM EDT SUN AUG 30 2015 .SYNOPSIS...WEAK SURFACE HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH EARLY WEEK. IN THE MEANTIME...AN UPPER LEVEL DISTURBANCE WILL TRACK NORTH FROM THE NORTHERN GULF OF MEXICO AND WILL CROSS THE WESTERN CAROLINAS LATE TONIGHT AND MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM SUNDAY... MID-LEVEL CIRCULATION CENTER CURRENTLY NEAR MOBILE BAY WILL DAMPEN INTO AN OPEN WAVE AND LIFT NORTH-NORTHEASTWARD ACROSS WESTERN GEORGIA TODAY AND THEN INTO THE WESTERN CAROLINAS TONIGHT THROUGH DAYBREAK MONDAY. TOP-DOWN MOISTENING WILL COMMENCE LATE THIS AFTERNOON AND THROUGH THE OVERNIGHT IN ADVANCE OF THIS FEATURE WITH ASSOCIATED 850-700MB SOUTHERLY FLOW ADVECTING PLUME OF HIGH ~2.0" PWAT(POSSIBLE REMNANT TROPICAL MOISTURE PLUME FROM DANNY)INTO EASTERN HALF OF THE CAROLINAS. DRY STABLE LOW-LEVEL AIRMASS ASSOCIATED WITH SURFACE HIGH PRESSURE CENTERED OVER THE AREA WILL ACT TO DETER RAIN CHANCES UNTIL THE ARRIVAL OF THE DPVA AND MOISTURE SURGE FROM THE SOUTH. THUS TODAY WILL BE MOSTLY DRY...WITH THE EXCEPTION OF A FEW SPRINKLES OR DIMINISHING ISOLATED SHOWER NEAR THE SC/NC BORDER...WITH RAIN CHANCES INCREASING FROM SOUTH TO NORTH AFTER MIDNIGHT. HIGHS TODAY AT OR JUST A CATEGORY BELOW NORMAL...HELD IN CHECK BY OPAQUE VEIL OF MID AND HIGH CLOUDS AHEAD OF THE EJECTING UPPER WAVE. HIGHS GENERALLY IN THE 80S. LOWS TONIGHT IN THE MID TO UPPER 60S. && .SHORT TERM /MONDAY AND MONDAY NIGHT/... AS OF 330 AM SUNDAY... SCATTERED SHOWERS SHOULD BE ONGOING ACROSS CENTRAL NC MONDAY MORNING AND SHOULD CONTINUE INTO THE AFTERNOON AND EVENING AS DAMPENED MID- LEVEL WAVE SHIFTS OFFSHORE BY THE AFTERNOON. WHILE UPPER FORCING LOOKS TO BE WANING/EXITING THE AREA BY EARLY AFTERNOON...TEMPERED DIURNAL HEATING WITHIN THE LINGERING MOIST ~2.0" PWAT AIRMASS IN PLACE ACROSS EASTERN NC MAY RESULT IN AN INCREASE IN COVERAGE MONDAY AFTERNOON ALONG WITH SOME THUNDER AS WEAK TO MODERATE BUOYANCY DEVELOPS(MUCAPE OF 700-1500 J/KG). WILL KEEP POPS IN THE CHANCE RANGES...HIGHEST IN THE EAST. RAIN CHANCES ARE EXPECTED TO DIMINISH FROM WEST TO EAST MONDAY EVENING AS BOTH UPPER FORCING AND MOIST PLUME SHIFT OFFSHORE. HIGHS WILL ULTIMATELY DEPEND ON PRECIP COVERAGE...RANGING FROM LOWER 80S IN WETTER MODEL SOLUTIONS TO MID/UPPER 80S WHERE SHOWERS ARE SCARCE. LOWS MONDAY NIGHT IN THE UPPER 60S TO LOWER 70S. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 400 AM SUNDAY... THE MODELS REMAIN IN RELATIVELY GOOD AGREEMENT REGARDING THE RE- DEVELOPMENT/DISCONTINUOUS RETROGRESSION OF A POSITIVELY-TILTED TROUGH FROM THE LOWER GREAT LAKES TO THE TX GULF COAST...THE NORTHERN PORTION OF WHICH IS FORECAST TO CROSS THE CENTRAL APPALACHIANS WED AND VA/NC WED NIGHT. THE SOUTHERN PORTION OF THE TROUGH --FORECAST TO BECOME A CLOSED ALONG THE WESTERN GULF COAST-- WILL DRIFT SLOWLY EAST AND ULTIMATELY MAY GET TRAPPED BENEATH AN AMPLIFYING CENTRAL CONUS RIDGE. IT REMAINS UNCLEAR...HOWEVER...IF THE CLOSED LOW WILL INDEED GET TRAPPED BENEATH IN REX BLOCK FASHION OR INSTEAD BECOME INCORPORATED INTO A SEPARATE CLOSED LOW FORECAST TO EVOLVE OFF THE MIDDLE ATLANTIC COAST - A PROCESS STARTED BY THE AFOREMENTIONED NORTHERN PORTION OF THE TROUGH FORECAST TO CROSS NC WED NIGHT. BEFOREHAND...A LOW-MID LEVEL SHEAR/TROUGH AXIS WILL BE LEFT BEHIND THE SHORTWAVE TROUGH FORECAST TO APPROACH AND CROSS NC IN SW FLOW ALOFT DURING THE NEAR TERM; AND THIS FEATURE WILL BISECT CENTRAL NC FROM NE TO SW AND SERVE AS A FOCUS FOR DIURNAL CONVECTION THROUGH WED...SOME OF WHICH WILL BE AUGMENTED BY THE AFOREMENTIONED SHORTWAVE TROUGH FORECAST TO EMERGE EAST OF THE APPALACHIANS LATE WED-WED NIGHT. WHILE THE REMNANTS OF ERIKA MAY REGENERATE OVER THE FAR NE GOM OR FL PANHANDLE...NOT NECESSARILY AS A TROPICAL ENTITY OWING TO THE PROXIMITY OF THE GOM UPPER LOW AND ASSOCIATED SYNOPTIC/BAROCLINIC EFFECTS...ANY ASSOCIATED AFFECTS WILL STILL LIKELY BE SUPPRESSED MOSTLY SOUTH AND/OR WEST OF CENTRAL NC BY THE FLOW PATTERN OUTLINED ABOVE. AS SUCH...AFTER AROUND OR SLIGHTLY ABOVE CLIMO PROBABILITIES OF DIURNAL PRECIPITATION TUE-WED...THE REMAINDER OF THE FORECAST PERIOD WILL BE CHARACTERIZED BY AOB CLIMO POP...AS RELATIVELY DRY NW FLOW ALOFT SETS UP ACROSS THE CENTRAL APPALACHIANS. PROJECTED AFTERNOON LOW LEVEL THICKNESS VALUES AROUND 1420 METERS THROUGH THE FORECAST PERIOD SHOULD SUPPORT HIGHS GENERALLY IN THE UPPER 80S. NEAR CLIMO LOWS MOSTLY 65-70. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/...
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AS OF 645 AM SUNDAY... WEAK SFC HIGH PRESSURE OVER THE CAROLINAS WILL RESULT IN LIGHT AND VARIABLE WINDS AND PREDOMINATELY VFR CONDITIONS THROUGH THE EVENING. A WEAKENING UPPER-LEVEL LOW...CURRENTLY OVER THE NORTHERN GULF OF MEXICO...WILL LIFT NORTH-NORTHEASTWARD AND OVER THE WESTERN CAROLINAS LATE TONIGHT/EARLY MONDAY. TOP-DOWN MOISTENING IS EXPECTED IN ADVANCE OF THIS FEATURE WITH RAIN/SHOWER CHANCES INCREASING FROM THE SOUTH BETWEEN 06 TO 12Z MONDAY. COULD SEE SOME MVFR CONDITIONS WITHIN THE HEAVIER SHOWERS...OTHERWISE.... EXPECT MOSTLY LOW END VFR CEILINGS. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE MONDAY AFTERNOON AND EVENING AS THE AFOREMENTIONED UPPER LEVEL DISTURBANCE MOVES THROUGH THE AREA. THEN THROUGH THE REMAINDER OF THE WEEK...SCATTERED SHOWERS AND THUNDERSTORMS WITH THEIR ASSOCIATED SUB-VFR CONDITIONS WILL BE POSSIBLE EACH DAY...ALONG WITH THE POTENTIAL OF LATE NIGHT AND EARLY MORNING AREAS OF LOW CLOUDS AND FOG.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...CBL SHORT TERM...CBL LONG TERM...26 AVIATION...CBL

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