Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 121749 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 149 PM EDT SAT APR 12 2014 .SYNOPSIS...PERSISTENT HIGH PRESSURE IN THE WESTERN ATLANTIC WILL MAINTAIN A DRY SURFACE RIDGE ACROSS THE CAROLINAS THROUGH SUNDAY. A COLD FRONT ASSOCIATED WITH A DEVELOPING LOW PRESSURE SYSTEM WILL SLOWLY APPROACH THE REGION FROM THE WEST ON MONDAY...THEN MOVE EAST ACROSS NORTH CAROLINA AND VIRGINIA MONDAY NIGHT AND TUESDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1030 AM SATURDAY... OFFSHORE HIGH PRESSURE CONTINUES TO RIDGE IN THE SOUTHEAST STATES THIS MORNING. A WEAK FRONT HAS SLIPPED INTO THE NORTHERN PORTIONS OF THE FORECAST AREA...BUT WILL QUICKLY WASH OUT/RETREAT BACK NORTH THROUGH THE AFTERNOON. THIS WILL LEAVE CENTRAL NC UNDER MOSTLY SUNNY SKIES AND WITH LOW LEVEL THICKNESS VALUES PROGGED TO BE SIMILAR TO WHAT WAS OBSERVED YESTERDAY...AM EXPECTING AFTERNOON HIGHS TO CLIMB INTO THE UPPER 70S TO LOWER 80S ONCE AGAIN. OVERNIGHT LOWS WILL LIKELY BE A COUPLE OF DEGREES WARMER THAN THIS MORNING AS LOW LEVEL MOISTURE WILL BEGIN TO INCREASE. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 315 AM SATURDAY... A SOUTHERN STREAM UPPER LOW MOVING INTO THE DESERT SW TODAY WILL TRACK INTO THE CENTRAL PLAINS ON SUN AND TN/OH VALLEY SUN NIGHT... WHILE NORTHERN STREAM SHORTWAVE ENERGY DIGS SOUTHEAST FROM THE PACIFIC NW INTO THE CENTRAL/SOUTHERN ROCKIES. SOUTHWEST FLOW ALOFT WILL STRENGTHEN OVER THE CAROLINAS AND MID-ATLANTIC SUN/SUN NIGHT AS THE UPPER LEVEL RIDGE ALONG THE EASTERN SEABOARD GRADUALLY SHIFTS OFFSHORE...IN ADVANCE OF A DEEP SYNOPTIC TROUGH PROGRESSING SLOWLY EAST INTO THE CENTRAL CONUS. ASIDE FROM SOME POTENTIAL FOR WEAK DCVA ASSOC/W SMALL AMPLITUDE WAVES IN STRENGTHENING SW FLOW ALOFT... FORCING FOR ASCENT WILL REMAIN NEGLIGIBLE ACROSS THE REGION. SFC HIGH PRESSURE WILL PERSIST NEAR BERMUDA ON SUNDAY AS SYNOPTIC SUBSIDENCE STRENGTHENS IN THE WESTERN ATLANTIC...MAINTAINING A RELATIVELY DRY SFC RIDGE AXIS EXTENDING SOUTHWEST INTO THE CAROLINAS. ALTHOUGH SOME SLOW/GRADUAL LOW-LEVEL MOISTENING IS EXPECTED...DIURNAL DESTABILIZATION WILL BE DIFFICULT AT BEST DUE TO A STRENGTHENING MID-LEVEL CAP EXPECTED ALONG THE SOUTHERN PERIPHERY OF AN ELEVATED MIXED LAYER ADVECTING NORTHEAST FROM THE LOWER MIDWEST INTO THE MID-ATLANTIC DURING THE DAY SUNDAY. WITH THE ABOVE IN MIND...EXPECT DRY CONDITIONS TO PREVAIL THROUGH SUN NIGHT. HIGHS ON SUN SHOULD BE SLIGHTLY WARMER THAN TODAY GIVEN SLIGHTLY HIGHER 1000-850 MB THICKNESSES IN THE PRESENCE OF FULL SUN...IN THE 79-83F RANGE. LOWS SUN NIGHT WILL ALSO BE WARMER BY AT LEAST SEVERAL DEGREES DUE TO GRADUAL AIRMASS MODIFICATION /LOW-LEVEL MOISTENING/ AND A POTENTIAL FOR STRATUS TO DEVELOP PRIOR TO SUNRISE. EXPECT LOWS AROUND 60F MON MORNING. -VINCENT && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY... ...A SIGNIFICANT SYSTEM WILL AFFECT THE REGION LATE MONDAY NIGHT THROUGH TUESDAY NIGHT... POSSIBLY INTO WEDNESDAY... TURNING SHARPLY COLDER MID-WEEK. MODELS WERE STILL ADVERTISING A VERY WET AND POTENTIALLY STORMY SYSTEM FROM THE MISSISSIPPI VALLEY TRACKING EASTWARD THROUGH OUR REGION DURING THE EARLY TO MID WEEK PERIOD. AN ENSEMBLE MEAN APPROACH USING MAINLY THE EUROPEAN AS GUIDANCE CONTINUES TO BE FAVORED. THIS WAS DUE IN PART TO THE LARGE SPREAD NOTED WITHIN THE MODEL SOLUTIONS CONCERNING TIMING AND STRENGTH OF THE SYSTEM AS IT PRESSES EASTWARD THROUGH THE MISSISSIPPI VALLEY TOWARD THE APPALACHIANS AND THE EASTERN SEABOARD. THIS ENSEMBLE MEAN APPROACH WILL CONTINUE TO BE FAVORED WHICH SUPPORTS THE MAIN WEATHER HAZARDS OF HEAVY RAIN AND POSSIBLE SEVERE THUNDERSTORM THREATS... CENTERED ON TUESDAY AND TUESDAY NIGHT. CURRENT PROJECTIONS INDICATE 1-2 INCHES OF RAIN WITH LOCALLY 3 INCHES POSSIBLE WITH TRAINING OF HEAVY RAIN POTENTIAL. IN ADDITION... ALTHOUGH INSTABILITY IS EXPECTED TO BE A MAIN LACKING INGREDIENT FOR A SEVERE WEATHER OUTBREAK... ISOLATED SEVERE THUNDERSTORMS MAY STILL BE POSSIBLE WITH THE SHARP COLD FRONTAL PASSAGE. HOWEVER... VERY DEEP MOISTURE INFLUX INTO THE COLD FRONT AND FRONTAL WAVE FAVOR THE HEAVY RAIN THREAT MORE THAN ISOLATED SEVERE STORMS. THIS IS YET TO BE DETERMINED. AFTER THE FRONT PASSES OUR REGION... MUCH COLDER TEMPERATURES WILL ADVECT INTO THE REGION DRIVEN BY GUSTY NE WINDS. THE HAZARDOUS WEATHER FOCUS WILL THEN TURN TO A POTENTIAL SECONDARY WAVE ALONG THE SHARP FRONT AS IT PUSHES OFFSHORE LATER TUESDAY INTO WEDNESDAY. IT WOULD NOT BE OUT OF THE REALM OF POSSIBILITIES FOR SOME WET SNOW FLAKES TO MIX WITH THE RAIN INTO SOME OF THE MORE ELEVATED PIEDMONT COUNTIES AROUND THE NW PIEDMONT TRIAD REGION. HOWEVER... IT WOULD OBVIOUSLY BE DIFFICULT TO GET ANY SNOW ACCUMULATION THIS TIME OF YEAR EAST OF THE MOUNTAINS. THEREFORE... EVEN IF THIS HAPPENS... IT IS NOT ANTICIPATED TO BE A WEATHER HAZARD IN CENTRAL NC. SENSIBLE WEATHER BY WEDNESDAY INTO THURSDAY WILL BE SHARPLY COLDER TEMPERATURES AND THE CHANCE OF A VERY CHILLY NE WIND DRIVEN RAIN (ESPECIALLY WEDNESDAY). HIGHS WEDNESDAY MAY FALL FROM THE 50S/40S DURING THE DAY. GRADUAL CLEARING IS THEN ANTICIPATED THU... WITH TEMPERATURES LIKELY DIPPING NEAR FROST/LIGHT FREEZE READINGS (30-35) FOR MANY AREAS BY THURSDAY AND/OR FRIDAY. && .AVIATION /18Z SATURDAY THROUGH FRIDAY/...
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AS OF 130 PM SATURDAY... VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE CURRENT TAF PERIOD. WINDS WILL BE GENERALLY LIGHT AND VARIABLE ACROSS THE NORTHERN HALF OF THE FORECAST AREA AS A WEAK BOUNDARY REMAINS DRAPED ACROSS THE CENTRAL NC...WITH LIGHT SOUTHWESTERLY WINDS ELSEWHERE. HOWEVER...AS THE BOUNDARY WASHES OUT...WINDS SHOULD BECOME MORE SOUTHERLY AT ALL TAF SITES THROUGH THE AFTERNOON/EVENING HOURS. THEN AFTER LIGHT AND VARIABLE WINDS OVERNIGHT...SOUTHERLY WINDS WITH GUSTS UP TO 15-20 MPH WILL DOMINATE ON SUNDAY. JUST SOME SCATTERED FLAT DIURNAL CU WITH BASES BETWEEN 4-6 KFT WILL BE POSSIBLE TODAY AND THEN EVEN MORE SO ON SUNDAY. OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE REMAINDER OF THE WEEKEND. LOW STRATUS/FOG MAY DEVELOP LATE SUNDAY NIGHT/EARLY MONDAY MORNING AS LOW LEVEL MOISTURE REALLY BEGINS TO INCREASE. THEN A PERIOD OF WIDESPREAD ADVERSE AVIATION CONDITIONS IS EXPECTED LATE MONDAY THROUGH TUESDAY AS A STRONG COLD FRONT APPROACHES FROM THE WEST. CONDITIONS WILL THEN IMPROVE AGAIN BY MIDWEEK.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...KRD SHORT TERM...VINCENT LONG TERM...BADGETT AVIATION...KRD

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