FXUS62 KRAH 140219 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1009 PM EDT MON OCT 13 2008 .SYNOPSIS... HIGH PRESSURE WILL BUILD SOUTH ACROSS THE MID ATLANTIC AND CAROLINAS THROUGH WEDNESDAY. TEMPERATURES WILL BE MUCH ABOVE NORMAL ON TUESDAY AND WEDNESDAY. A COLD FRONT WILL MOVE ACROSS THE AREA LATE THURSDAY AND FRIDAY... RESULTING IN COOLER AND MORE SEASONABLE TEMPERATURES FOR THE WEEKEND. && .NEAR TERM /THROUGH TUESDAY/... AS OF 1009 PM MONDAY... JUST MINOR ADJUSTMENTS MADE TO THE NEAR TERM FORECAST. ABUNDANT CIRRUS CONTINUES TO DRIFT SOUTHWARD AROUND UPPER LEVEL HIGH CENTERED OVER THE TN VALLEY. QUESTIONABLE AS TO WHAT EFFECT THIS CIRRUS WILL HAVE ON MIN TEMPS AND FOG DEVELOPMENT. CIRRUS APPEARS THIN ENOUGH TO HAVE MINIMAL EFFECT ON TEMPS. HOWEVER DEWPOINTS ARE A FEW DEGREES WARMER THAN SAME TIME LAST NIGHT. DUE TO THE CIRRUS AND THE WARMER DEWPOINTS...HAVE ADJUSTED MIN TEMPS UP A DEGREE OR TWO FROM THE PREVIOUS FORECAST IN MOST LOCALES. AS FAR AS FOG DEVELOPMENT...THE WARMER DEWPOINTS INDICATE POTENTIAL FOR A NARROW TEMP/DEWPOINT SPREAD OVERNIGHT...SUGGESTING FAVORABLE DEVELOPMENT OF FOG. HAVE EXPANDED THE PATCHY FOG TO INCLUDE MOST OF THE AREA. WOULD NOT BE SURPRISED IF FOG IS MORE PREVALENT THAN FORECAST. AS FAR AS TUESDAY...THICKNESSES THIS AFTERNOON REACHED INTO THE MID 1390S WHICH RESULTED IN MAX TEMPS IN THE UPPER 70S TO AROUND 80. THICKNESSES TUESDAY PROJECTED TO BE 10-12M WARMER WHICH SUGGEST MAX TEMPS ABOUT 4 DEGREES WARMER. CANNOT RULE OUT SOME DRY ADIABATIC WARMING WITH 850/700MB HIGH CENTERED OVERHEAD. THIS WHICH WOULD ADD ANOTHER DEGREE OR TWO. THUS WOULD FAVOR MAX TEMPS TUESDAY BETWEEN 83-86. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... AS OF 145 PM... THE THURSDAY NIGHT THREAT FOR RAIN...ABSENT FOR A WHILE ON THE GFS MODEL...HAS RETURNED. HOWEVER WILL CONTINUE OMISSION FOR NOW. ANY CHANCE FOR RAIN HINGES ON THE 850 MILLIBAR TROUGH WHICH LAGS THE SURFACE TROUGH. THE 850 TROUGH IS BROAD AND DIFFUSE AND SIGNIFICANT DYNAMICS THIS FAR SOUTH IS NOT ASSURED. SHOULD THE THREAT DEVELOP IT WOULD BE AFTER MIDNIGHT. PRIOR TO THURSDAY NIGHT...THE OCTOBER HEAT WAVE CONTINUES. STRONG UPPER LEVEL HIGH PRESSURE OVER NORTHERN GEORGIA TUESDAY EVENING SLIPS TO CENTRAL FLORIDA THURSDAY EVENING. THICKNESS VALUES SUGGEST NEAR RECORD AFTERNOON TEMPERATURES WEDNESDAY AND THURSDAY AT 84 TO 89 AND THIS IS ACCEPTED. SLIGHTLY ABOVE NORMAL MORNING LOWS WEDNESDAY WILL RISE TO THE UPPER 50S TO LOWER 60S FOR THURSDAY AND FRIDAY MORNING. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 145 PM... SURGE OF COLDER AIR INTENSIFIES DURING THE DAY FRIDAY WITH 850 MILLIBAR TROUGH FORECAST TO MOVE THROUGH CENTRAL NORTH CAROLINA FRIDAY AND FRIDAY NIGHT. THIS WILL BRING A CHANCE OF RAIN TO THE AREA... AND BE AIDED BY A STRONG UPPER LEVEL TROUGH PASSAGE FRIDAY NIGHT. A FEW INSTABILITY SHOWERS AFTER SUNRISE SATURDAY MORNING POSSIBLE...WITH THE UPPER TROUGH SLIPPING EAST AND ENDING ANY RAIN THREAT SATURDAY AFTERNOON. SURFACE HIGH PRESSURE DOMINATES THE REMAINDER OF THE FORECAST. FRIDAY HIGH TEMPERATURES ARE A DIFFICULT CALL. SIGNIFICANT RAIN FRIDAY COULD EASILY KEEP TEMPERATURES IN THE 60S IN THE NORTH. WILL LEAVE AT LOW TO MID 70S IN CENTRAL NORTH CAROLINA WITH AN EYE TOWARD LOWERING IF CONFIDENCE IN RAINFALL INCREASES. TEMPERATURES FOR THE REMAINDER OF THE WEEKEND AND MONDAY WILL CONTINUE TO BE FORECAST ABOVE GUIDANCE DUE TO THE TENDENCY OF MODELS TO OVERDEEPEN COASTAL LOWS... PULLING IN TOO MUCH COLD AIR FROM THE NORTH... AND THE GENERAL GFS MODEL COLD BIAS THIS FAR OUT IN TIME. AFTERNOON HIGHS MID 60S TO LOWER 70S. LOWS 45 TO 55. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... AS OF 735 PM MONDAY... SFC HIGH PRESSURE CENTERED OVER THE REGION WILL ALLOW FOR LIGHT WINDS AND GOOD RADIATIONAL COOLING CONDITIONS OVERNIGHT. THERE WILL BE NO CEILING CONCERNS AS VERY DRY AIR CONTINUES TO EXIST IN THE LOW AND MID LEVELS. HOWEVER...SCATTERED CIRRUS WILL MOVE INTO THE REGION FROM THE NORTH OVERNIGHT. THIS HIGH CLOUD COVER WILL ULTIMATELY AFFECT THE EXTENT OF RADIATION FOG DEVELOPMENT TOWARD DAWN. FOR NOW...WILL FORECAST MVFR FOG AT RDU/FAY WITH IFR CONDITIONS AT THE MORE FOG PRONE RWI. LOWER DEWPOINTS AT GSO/INT ARE EXPECTED TO PRECLUDE FOG DEVELOPMENT AT THOSE TERMINALS. THE DAYTIME HOURS OF TUESDAY WILL BE VFR WITH WINDS GRADUALLY SHIFTING TO MORE OF A SOUTHWEST COMPONENT. VFR CONDITIONS WILL PERSIST THROUGH THURSDAY. THE NEXT CHANCE FOR ADVERSE AVIATION CONDITIONS ARE EXPECTED TO OCCUR DURING THE LATTER PORTION OF THE WEEK. THE LONG RANGE MODELS SHOW A COLD FRONT APPROACHING CENTRAL NORTH CAROLINA FROM THE WEST SOMETIME THURSDAY NIGHT. THE COLD FRONT MAY STALL OUT OVER PORTIONS OF CENTRAL NORTH CAROLINA DURING THE DAY FRIDAY...WITH THE UPPER LEVEL TROUGH MOVING OVERHEAD AND PUSHING THE SURFACE FRONT AND/OR WEAK LOW OFFSHORE SOMETIME FRIDAY NIGHT. && .CLIMATE... RECORD HIGHS FOR TUESDAY OCTOBER 14: RDU - 86 (1985) GSO - 85 (1975) RECORD HIGHS FOR WEDNESDAY OCTOBER 15: RDU - 88 (1985) GSO - 87 (1985) RECORD HIGHS FOR THURSDAY OCTOBER 16: RDU - 85 (1989) GSO - 85 (1953) && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...WSS AVIATION...JFB/VINCENT CLIMATE...HARTFIELD