AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 341 AM EDT FRI OCT 17 2014 .SYNOPSIS...A DRY COLD FRONT WILL APPROACH THE MOUNTAINS FROM THE WEST TONIGHT...THEN PROGRESS THROUGH THE CAROLINAS SATURDAY MORNING. IN THE WAKE OF THE FRONT...HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHWEST THROUGH EARLY NEXT WEEK. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 315 AM FRIDAY... TODAY: H5 HEIGHT RISES ON THE ORDER OF 120-140 METERS/12-HR WILL PREVAIL OVER THE CAROLINAS AND MID-ATLANTIC TODAY AS A POTENT UPPER LEVEL LOW LIFTS NORTHWARD FROM THE LOWER GREAT LAKES INTO CANADA. STRONG SUBSIDENCE WILL ACCOMPANY THE TRANSITION FROM MERIDIONAL TO ZONAL FLOW ALOFT TODAY...AS EVIDENCED BY PRONOUNCED MID-LEVEL WARMING/ DRYING AND INCREASINGLY STABLE THERMAL PROFILES PER 00Z GFS/NAM FORECAST SOUNDINGS. WITH THE ABOVE IN MIND...EXPECT CLEAR SKIES WITH HIGHS SEVERAL DEGREES WARMER THAN YESTERDAY (LOWER/MID 70S) IN ASSOCIATION WITH WEAK LOW-LEVEL WARM ADVECTION FROM THE SOUTHWEST THIS AFTERNOON. TONIGHT: AN UPPER LEVEL LOW (AND ATTENDANT SFC LOW) CENTERED OVER MINNESOTA EARLY THIS MORNING WILL DIG SOUTHEAST THROUGH THE UPPER GREAT LAKES INTO THE NORTHERN MID-ATLANTIC TONIGHT...WITH AN ASSOCIATED COLD FRONT TRACKING EAST THROUGH THE TN/OH VALLEY TO THE APPALACHIANS BY 00Z THIS EVENING...PROGRESSING INTO CENTRAL NC BETWEEN 06-12Z SAT. LOW-LEVEL WARM ADVECTION WILL DEVELOP OVER THE REGION BETWEEN 21-06Z AS A 20-25 KT SOUTHWESTERLY LLJ OVERSPREADS THE CAROLINAS IN ADVANCE OF THE APPROACHING FRONT...HOWEVER...THE MAGNITUDE/DURATION OF SUCH FORCING WILL BE INSUFFICIENT TO SUPPORT CLOUD COVER (LET ALONE PRECIPITATION)...ESP IN THE PRESENCE OF A PROFOUNDLY SUBSIDENT ANTECEDENT AIRMASS. WITH THE ABOVE IN MIND... EXPECT CLEAR OR MOSTLY CLEAR SKIES TONIGHT WITH LOWS WARMER THAN THIS MORNING...IN THE MID 50S TO LOWER 60S...DUE TO WEAK WARM ADVECTION AND A LIGHT SOUTHWEST BREEZE OVERNIGHT. -VINCENT && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... AS OF 330 AM FRIDAY... A DRY/SUBSIDENT COLUMN WILL PERSIST ON SATURDAY WITH CONTINUED DRY CONDITIONS. WEAK COLD ADVECTION WILL DEVELOP ACROSS THE REGION ON SAT IN THE WAKE OF A DRY COLD FRONTAL PASSAGE SAT MORNING. COLD ADVECTION WILL BE PRESENT THROUGHOUT THE DAY (ESP NORTH NEAR THE VA BORDER)...THOUGH THE BEST COLD ADVECTION WILL LARGELY OCCUR AFTER PEAK HEATING IN THE 21-06Z TIME FRAME SAT EVENING/EARLY SAT NIGHT AS HIGH PRESSURE BUILDS EASTWARD FROM THE LOWER MIDWEST INTO THE WESTERN TN/OH VALLEY. EXPECT HIGHS IN THE LOWER/MID 70S SAT... WITH LOWS SAT NIGHT IN THE MID/UPPER 40S. -VINCENT && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 300 AM FRIDAY... LITTLE CHANGE TO THE CURRENT DRY AND COOL EXTENDED FORECAST. THE LATEST MODELS ARE IN GOOD OVERALL AGREEMENT IN THE PLACEMENT OF A MEAN MID/UPPER TROUGH OVER THE GREAT LAKES TO NEW ENGLAND EARLY TO MID WEEK. THE INITIAL COOL/DRY SURFACE HIGH PRESSURE IS EXPECTED TO BUILD INTO OUR REGION FROM THE NW ON SUNDAY... THEN SHIFT SLOWLY OFF THE COAST MONDAY. SUNDAY AND MONDAY ARE FORECAST TO BE COOL AND DRY WITH LOWS IN THE 40S. HIGHS IN THE 60S. A SECOND DRY COLD FRONT IS FORECAST TO ARRIVE LATE MONDAY NIGHT AND EARLY TUESDAY. TUESDAY WILL BE THE WARMEST OF THE DAYS AS THE DEEP CAA WILL NOT BE FELT UNTIL LATE IN THE DAY. HIGHS 65-72 EXPECTED. STRONG CAA SHOULD BE FELT WEDNESDAY. IN ADDITION... SPORADIC CLOUDINESS CAN BE EXPECTED ESPECIALLY DURING THE AFTERNOON WITH UNSTABLE CONDITIONS DUE TO HEATING UNDER THE COLD MID/UPPER TROUGH... ESPECIALLY OVER VA AND NORTHERN NC. HIGHS MAY STRUGGLE TO REACH 60 IN THE NORTH WEDNESDAY... THEN AGAIN ON THURSDAY ESPECIALLY IN THE TRIAD AND TRIANGLE AREAS. -BADGETT && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 215 AM FRIDAY... 24 HOUR TAF PERIOD: VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD IN ASSOCIATION WITH A DRY/SUBSIDENT AIRMASS IN PLACE ACROSS THE REGION. A LIGHT SOUTHWEST BREEZE THIS MORNING WILL INCREASE TO 8- 13 KT THIS AFTERNOON...BECOMING WSW AND DECREASING TO 5 KT OR LESS AFTER SUNSET THIS EVENING. CLEAR SKIES WILL PERSIST THROUGH TONIGHT. LONG TERM: VFR CONDITIONS ARE EXPECTED THROUGH EARLY NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE NORTHWEST IN THE WAKE OF A DRY FRONTAL PASSAGE EARLY SAT. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. &&
Posted on: Fri, 17 Oct 2014 10:54:25 +0000
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