AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC ISSUED BY NATIONAL WEATHER SERVICE CHARLESTON SC 141 PM EDT FRI JUL 8 2011 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL MAINTAIN A MOIST SOUTHERLY FLOW ACROSS THE EASTERN CAROLINAS INTO THE WEEKEND. TROPICAL MOISTURE MOVING NORTHWARD ACROSS THE EASTERN CAROLINAS WILL BRING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS INTO THE WEEKEND. SOME OF THIS RAIN WILL BE HEAVY AT TIMES. BERMUDA HIGH PRESSURE WILL BUILD BACK ACROSS THE AREA EARLY NEXT WEEK. A COLD FRONT MAY APPROACH THE AREA DURING THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... TROPICAL MOISTURE WILL CONTINUE TO STREAM NORTHWARD OVER THE NEARBY...AS THE DEEPEST MOISTURE SKIRTS THE FORECAST AREA OVER THE ATLANTIC. WITH PWATS OF 2-2.5 INCHES WE LOOK FOR SOME OF THE RAIN TO BE HEAVY AT TIMES. FLASH FLOOD GUIDANCE INDICATES THAT WE WILL NOT REACH OUR 3 OR 6 HOUR THRESHOLDS...SO HAVE HELD OFF ON A FLOOD WATCH. OUR ATTENTION THEN SHIFTS TO FAR INLAND ZONES WHERE TEMPS ARE CLIMBING WELL INTO THE 80S AND LOWER 90S. CONVECTIVE LOOKING CUMULUS CLOUDS ARE CONTINUING TO FORM ON THE BACK EDGE OF THE THICK CIRRUS SHIELD AND A STRONG DIFFERENTIAL HEATING BOUNDARY WILL CONTINUE TO DEVELOP. AS A WELL DEFINED SHORT WAVE TROUGH IN THE OHIO VALLEY MOVES EAST AND AIR MASS DESTABILIZATION TAKES PLACE WE HAVE TO BE CONCERNED WITH A SEVERE WEATHER POTENTIAL. THE HAZARDOUS WEATHER OUTLOOK ADDRESSES THIS CONCERN. WE LOOK FOR A LARGE RANGE OF TEMPS FROM WEST TO EAST THIS AFTERNOON...WITH COASTAL SECTIONS ONLY IN THE LOWER AND MIDDLE 80S...BUT IN TO THE LOWER OR PERHAPS 90S FAR WEST. POPS WILL BE IN THE LIKELY RANGE 60-70 PERCENT THROUGH THE REMAINDER OF THE AFTERNOON. LLJ DEVELOPING OVERNIGHT WILL HELP KEEP A MIXED ATMOSPHERE UNDER CLOUDY SKIES...KEEPING MINIMUM TEMPERATURES ABOVE NORMAL...MID TO UPPER 70S MOST LOCATIONS. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 AM FRIDAY...RAIN IS A GOOD BET ESPECIALLY SATURDAY INTO SATURDAY NIGHT...THANKS TO THE COMBINATION OF A SLOW-MOVING BOUNDARY OVERHEAD AND A JUICY ATMOSPHERE WITH PRECIPITABLE WATER VALUES OVER 2 INCHES. WILL CARRY LIKELY POPS ESPECIALLY SAT AFTERNOON...WITH PROBABLY THE BEST WIDESPREAD QPF THE ILM CWA HAS SEEN IN A FEW WEEKS. PRECIP CHANCES DIMINISH LATER SATURDAY NIGHT AND SUNDAY AS A WEAK UPPER TROF SLIPS OFF THE COAST...GIVING WAY TO THE BUILDING RIDGE FROM THE DEEP SOUTH. STILL A LOT OF LOW- LEVEL MOISTURE...AND SHOULD BE PLENTY OF BOUNDARIES AROUND IF SATURDAY CONVECTION PANS OUT. THEREFORE HAVE MAINTAINED CHANCE POPS THRU THE DAY ON SUNDAY. MAX TEMPS WILL LEAN TOWARD THE COOLER NAM MOS...ESPECIALLY ON SATURDAY BUT THAT STILL GETS US AROUND 90. MIN TEMPS SEVERAL DEGREES ABOVE CLIMO AND ON THE HIGH SIDE OF GUIDANCE...MID 70S SAT NIGHT. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 3 AM FRIDAY...DOG DAYS OF SUMMER WILL BE IN FULL SWING AS UPPER RIDGE BUILDS OVER THE DEEP SOUTH FOR THE FIRST HALF OF NEXT WEEK. BY LATE TUESDAY 850MB TEMPS WARM TO +22C BUT ENOUGH OF A SUBSIDENCE SIGNATURE THAT THE BIGGER STORY MAY BE OPPRESSIVE HUMIDITY AS THE DEPTH OF MIXING IS LIMITED. MAX TEMPS WILL RANGE FROM AROUND 90 AT THE COAST TO MID 90S INLAND...BUT DEWPOINTS WILL REMAIN IN THE LOWER/MID-70S TO MAKE IT FEEL LIKE 100+. BEST SHOT AT MEETING ADVISORY WILL BE TUESDAY AND PERHAPS WEDNESDAY WITH MOISTURE POOLED ALONG A WEAK COLD FRONT. MIN TEMPS WELL ABOVE CLIMO...AND AT THEIR WARMEST ON TUE NIGHT A FEW LOCATIONS WILL NOT EVEN DIP BELOW 80. THE FRONT SHOULD ACTUALLY MAKE IT OFF THE COAST WEDNESDAY OR WED NIGHT...BUT WILL ONLY KNOCK TEMPS AND DEWPOINTS BACK DOWN AROUND CLIMO FOR THURSDAY. POPS REMAIN LIMITED TO DIURNAL SLIGHT CHANCE THRU THE PERIOD. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... CONDITIONS WILL VARY FROM VFR TO POSSIBLY IFR AT TIMES AS SHOWERS AND THUNDERSTORMS AFFECT THE REGION THIS AFTERNOON. WITH PLENTY OF LOW LEVEL MOISTURE...PERIODIC HEAVY DOWNPOURS ARE EXPECTED FOR ALL SITES. THUS...INCLUDED TEMPO GROUPS WITH REDUCED VISIBILITIES AND LOWERING CEILINGS. HOWEVER...CAN NOT RULE OUT BRIEF TIME PERIODS WHERE VISIBILITIES DROP BELOW IFR CONDITIONS. EXPECT CONVECTION ACTIVITY TO DECREASE SHORTLY AFTER SUNSET...ESPECIALLY FOR INLAND SITES. HAVE HELD ONTO CBS AFTER 01Z FOR ALL COASTAL SITES AS CONVECTION MAY LINGER OVER THE WATERS NEAR COASTAL AREAS. LOW LEVEL MOISTURE WILL LINGER OVERNIGHT WITH BOTH THE SREF MODEL AND MODEL SOUNDINGS HINTING AT EITHER A LOW STRATUS LAYER OR PATCHY FOG DEVELOPMENT EARLY SATURDAY MORNING. POTENTIAL FOR FOG DEVELOPMENT IN CONJUNCTION WITH LOW STRATUS APPEARS BETTER ACROSS INLAND SITES AS WINDS WILL REMAIN 5 KNOTS OR LESS AFTER 08Z. HOWEVER...STRONGER WINDS WILL REMAIN ACROSS COASTAL AREAS WHICH WILL LIKELY HINDER ANY FOG POTENTIAL. THUS EXPECT LOW STRATUS TO BE MORE LIKELY FOR THESE COASTAL AREAS. ANY REDUCED CONDITIONS WILL LIKELY IMPROVE TO IFR CONDITIONS BY LATE SATURDAY MORNING...HOWEVER ANOTHER ROUND OF CONVECTION COULD AFFECT ALL SITES TOWARD THE END OF THIS TAF PERIOD. EXTENDED OUTLOOK...WIDESPREAD SHOWERS AND THUNDERSTORMS LIKELY THROUGHOUT THE WEEKEND. PRECIP CHANCES DECREASE EARLY NEXT WEEK. && .MARINE... NEAR TERM /THROUGH TONIGHT/... MODERATE S/SWLY FLOW AROUND THE BACKSIDE OF THE BERMUDA HIGH WILL GIVE WAY TO INCREASING WINDS THIS EVENING AND OVERNIGHT WITH THE DEVELOPMENT OF A LOW LEVEL JET. WINDS WILL INCREASE INTO THE 20 TO 25 KT RANGE LATE THIS EVENING AND OVERNIGHT. HAVE RAISED SEAS A BIT BASED ON THE LATEST OBS WHICH PUTS THE NEARSHORE NC WATERS INTO ADVISORY LEVELS FOR TODAY SO HAVE BUMPED UP THE STARTING TIME OF THE ADVISORY FOR THESE AREAS. WINDS SHOULD MOSTLY REMAIN BELOW ADVISORY LEVELS THROUGH THIS AFTERNOON...EXCEPT IN SHOWERS AND TSTMS. SHORT TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 AM FRIDAY...NEARLY STATIONARY FRONT WILL MEANDER NEAR THE CAROLINA COAST FOR MOST OF THE PERIOD. LOOK FOR A WEAKENING SW WIND ON SATURDAY...PROBABLY GOING LIGHT AND VARIABLE ON SUNDAY WITH THE FRONT DIRECTLY OVERHEAD. SEAS WILL INITIALIZE AT 4-5 FT SATURDAY MORNING WITH A GRADUAL SUBSIDING TREND FOR THE REST OF THE WEEKEND. SEMI-PERMANENT 9-SEC SE SWELL IS THERE BUT NOT TOO PRONOUNCED. LONG TERM /SUNDAY NIGHT THROUGH TUESDAY/... AS OF 3 AM FRIDAY...WEAK HIGH PRESSURE OFF THE NEW ENGLAND COAST AND DISSIPATING FRONT OFF THE SC/GA COAST WILL MAINTAIN AN EASTERLY WIND INITIALLY. FLOW WILL COME AROUND TO THE SOUTH MONDAY AS THE FRONT BECOMES MORE WASHED OUT...AND THE HIGH RETREATS OFFSHORE AND IS ABSORBED INTO THE BERMUDA HIGH. WINDS WILL REMAIN QUITE LIGHT...WITH TUESDAY ONLY APPROACHING 15 KT AS A PIEDMONT TROF BECOMES MORE PRONOUNCED. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT SATURDAY FOR AMZ254-256. SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR AMZ250-252. && $$