305 FXUS62 KILM 110135 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 935 PM EDT TUE AUG 10 2010 .SYNOPSIS... HEAT AND HUMIDITY WILL CONTINUE ACROSS THE AREA FOR THE NEXT FEW DAYS AS HIGH PRESSURE BOTH AT THE SURFACE AND ALOFT STRENGTHENS. RAIN CHANCES WILL INCREASE TOWARD THE END OF THE WEEK AND INTO EARLY NEXT WEEK AS A COLD FRONT DIPS SOUTH INTO THE CAROLINAS. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS OF 9:30 PM TUESDAY...CONVECTION HAS ENDED FOR THE NIGHT. A STRONG CAP TODAY HELPED ENSURE THAT THERE WAS NEVER THAT MUCH OF IT TO BEGIN WITH...JUST SOME SPOT SHOWERS ALONG THE SEA BREEZE FRONT WITH NO THUNDER. STRONG SYNOPTIC UPPER RIDGING WILL KEEP RAIN CHANCES OVERNIGHT NEAR ZERO. UNLIKE THE PAST FEW NIGHTS...A STEADY LIGHT SWLY FLOW WILL KEEP UP OVERNIGHT...MAKING FOG UNLIKELY ALSO. SOME TRANSIENT CIRRUS BLOWOFF FROM DISTANT CONVECTION WILL MOVE BY OVERHEAD...OTHERWISE CLEAR SKIES OVERNIGHT. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AS OF 2:45 PM TUESDAY...500MB RIDGE WILL GET PUSHED TO THE SOUTH DURING THIS PERIOD WHICH ALLOWS A NUMBER OF SHORTWAVES TO RIDE THE RETREATING RIDGE WHICH IN TURN ALLOWS A SURFACE FRONT TO DROP DOWN INTO THE AREA BY FRIDAY MORNING. THE NAM IS A LITTLE MORE AGGRESSIVE WITH THE SOUTHWARD PROGRESSION OF THE FRONT BY FRIDAY MORNING. WILL GENERALLY FOLLOW THE MORE AGGRESSIVE NAM FOR THIS PACKAGE AS IT HAS BEEN VERY CONSISTENT ON THE TIMING AND PLACEMENT OF THESE FEATURES. GENERALLY FOLLOWED THE SREF ENSEMBLES FOR POPS WHICH ARE ESSENTIALLY A FUNCTION OF THE NAM. THIS MODEL HAS A MCS MOVING ACROSS OUR AREA BY 1200 UTC THURSDAY MORNING AND MORE SCATTERED ACTIVITY LATE THURSDAY INTO FRIDAY MORNING ASSOCIATED WITH THE FRONT. ESSENTIALLY I HAVE THE HIGHEST POPS LATE WEDNESDAY INTO THURSDAY MORNING WITH A LULL VIA NVA THURSDAY. LOWER POPS FOR LATE THURSDAY INTO FRIDAY TO REFLECT THE MORE ANTICIPATED SCATTERED NATURE OF THE CONVECTION. ONCE AGAIN LEANED TOWARD THE NAM/MET NUMBERS FOR TEMPERATURES...WHICH ONCE AGAIN LEAD TO THE POSSIBILITY OF A HEAT ADVISORY FOR BOTH AFTERNOONS. HOWEVER WITH ONLY A FEW SITES ECLIPSING 105 DEGREES WILL LET THE MIDNIGHT SHIFT MAKE THE FINAL CALL. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 2:45 PM TUESDAY...COLD FRONT DROPPING IN FROM THE NORTH WILL BE ACROSS THE NORTHERN PORTION OF THE FORECAST AREA AT THE START OF THE PERIOD. LOT OF UNCERTAINTY WITH RESPECT TO THE LOCATION OF THE FRONT WHEN IT STALLS SAT/SUN. GFS/NAM STALL THE BOUNDARY JUST SOUTH OF THE ILM AREA...WHILE THE FAVORED ECMWF/CANADIAN STALL IT ACROSS THE SOUTHERN PORTION OF THE ILM AREA. THE BOUNDARY WILL REMAIN IN THE AREA THROUGH THE END OF THE PERIOD...GRADUALLY WEAKENING TO LITTLE MORE THAN A SURFACE TROF BY NEXT WEEK. WEAK NORTH TO NORTHWEST FLOW ALOFT FOR MUCH OF THE PERIOD WITH UPPER RIDGE SUPPRESSED TO THE SOUTH. COMBINATION OF STALLED SURFACE BOUNDARY...ABUNDANT LOW LEVEL MOISTURE...AND WEAK IMPULSES MOVING ACROSS THE AREA LEADS TO CHC POPS EACH AFTERNOON. HARD TO DETERMINE WHICH DAYS MAY BE FAVORED AT THESE TIME RANGES...SO WILL CONTINUE TO CARRY 30S BY DAY AND 20S OVERNIGHT. TEMPERATURES NEAR CLIMO DURING THE DAY AND ABOVE CLIMO OVERNIGHT. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... AS OF 00Z...HIGH CONFIDENCE IN VFR THROUGH THE VALID PERIOD WITH ONLY SLIGHT CHANCE OF SOME FOG AT THE INLAND TERMINALS OVERNIGHT. RIDGING THROUGHOUT THE ATMOSPHERIC COLUMN CONTINUES TO DOMINATE THE SYNOPTIC PATTERN ALLOWING FOR ONLY LIMITED CLOUD COVER AND SHALLOW CONVECTIVE SHOWER ACTIVITY. THE FEW SHOWERS AND CONVECTIVE CU WILL DISSIPATE RAPIDLY IN THE NEXT FEW HOURS LEAVING ONLY SCT CIRRUS OVER THE TERMINALS. SW SURFACE WINDS WILL REMAIN ELEVATED TONIGHT SO FOG APPEARS TO BE ONLY OF LITTLE CONCERN. THE SW WINDS WILL NOT ONLY KEEP THINGS MIXED THROUGH THE OVERNIGHT...BUT WILL ALSO KEEP MIN TEMPS ABOVE CROSS OVERS. STILL...FOR PERSISTENCE AND TO ACCOUNT FOR VERY HIGH TD/S...HAVE MVFR FOG AT LBT/FLO FOR A FEW HOURS TOWARDS MORNING. CONFIDENCE IS LOW IN FOG DEVELOPMENT THOUGH...AND MAY REMOVE ALL VSBY RESTRICTIONS WITH 06Z ISSUANCE. AFTER SUNRISE ANY FOG WILL BURN OFF LEAVING UNRESTRICTED VSBYS AND VFR DIURNAL CU THROUGH THE AFTN/EVE. BUFR PROFILES SHOW MORE MOISTURE THROUGH THE COLUMN THAN PREVIOUS DAYS...SO MORE CU DEVELOPMENT SEEMS LIKELY...BUT MID LEVEL CAP WILL STILL PRECLUDE MUCH IN THE WAY OF SHOWER ACTIVITY. HAVE JUST GONE SCT CU AGAIN...BUT VFR CIGS ARE POSSIBLE DURING WEDNESDAY AFTN. WINDS WILL CONTINUE FROM THE S/SW AT 8 TO 14 KTS THROUGH THE END OF THIS VALID PERIOD. EXTENDED OUTLOOK...MORNING FOG WITH A SLIGHT CHANCE OF IFR AT THE INLAND TERMINALS AND CRE ON THURSDAY. COLD FRONT WILL APPROACH THE AREA FOR THE WKND WITH CHANCE FOR IFR CONDITIONS FROM CONVECTION AHEAD OF IT. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 9:30 PM TUESDAY...WINDS CURRENTLY IN THE 15 TO 20 KT RANGE FROM THE SOUTH TO SW OVER THE WATERS. THIS IS THE LAST GASP OF SEA BREEZE ENHANCED WIND FLOW FROM TODAY AND WILL GRADUALLY DECREASE OVERNIGHT. THE FLOW WILL VEER TO A SWLY DIRECTION AND WEAKEN TO AROUND 10 KT PRIOR TO DAYBREAK. WAVES WILL AVERAGE 3 FT. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 2:45 PM TUESDAY...SOUTHWEST FLOW WILL CONTINUE THROUGH THE PERIOD WITH AN OCCASIONAL INCREASE FROM THE 10-15 KNOT RANGE INTO THE 15-20 KNOT RANGE. THIS WILL OCCUR LATE WEDNESDAY AS A PRE- FRONTAL TROUGH MOVES CLOSER INCREASING THE THE GRADIENT AND AGAIN LATE THURSDAY AS THE ACTUAL FRONT MOVES CLOSER. SWAN IS ADVERTISING SOME FIVE FOOTERS TO ENCROACH INTO THE MARINE ZONES DURING THESE TIMES AND A SCEC MAY BE WARRANTED. OTHERWISE 2-4 FEET WILL SUFFICE. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 2:45 PM TUESDAY...QUESTIONS REMAIN AS TO WHETHER THE FRONT WILL PUSH SOUTH OF THE WATERS SAT OR REMAIN STALLED ACROSS THEM. CURRENTLY FAVOR THE 00Z ECMWF SOLUTION WHICH HAS THE FRONT OVER OR JUST SOUTH OF THE SC ZONES. THIS WILL KEEP WINDS SPEEDS ARE ON THE LIGHT SIDE...GENERALLY 10 KT OR LESS. DIRECTION WILL MAINLY BE NORTHEASTERLY TO EASTERLY ONCE THE FRONT PUSHES THROUGH FRI NIGHT INTO SAT. BEFORE FRONT PASSES...LIGHT WINDS WITH A SOUTHERLY COMPONENT CAN BE EXPECTED. CLOSE TO WHERE THE FRONT STALLS WIND DIRECTION WILL BE MORE VARIABLE AND DIFFICULT TO PIN DOWN. SEAS THROUGH THE PERIOD WILL RUN 2 TO 3 FT WITH SOME 4 FT POSSIBLE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...REK NEAR TERM...REK SHORT TERM...SHK LONG TERM...III AVIATION...JDW MARINE...ALL