000 FXUS62 KILM 010144 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 945 PM EDT SAT JUL 31 2010 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE WILL BRING AN INCREASING RISK FOR SHOWERS AND A FEW THUNDERSTORMS THROUGH SUNDAY MORNING WHILE HIGH PRESSURE HOLDS ON TO THE NORTH. THE MIDWEEK PERIOD WILL BRING A GRADUAL TRANSITION TO A MORE BERMUDA HIGH DOMINATED WEATHER PATTERN. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 9 PM SATURDAY...AIRMASS ACROSS THE FORECAST AREA HAS BEEN FAIRLY STABLE ALL EVE AND SO THUNDERSTORMS TO OUR W HAVE WEAKENED AS THEY APPROACHED AND THEN MOVED INTO THE WESTERNMOST ZONES. MODELS HAVE BEEN CONSISTENT FOR SEVERAL RUNS NOW IN SHOWING AREAS OF CONVECTION PERSISTING OVERNIGHT AND INTO SUN. A SHORTWAVE TROUGH EMBEDDED IN WNW FLOW WILL CROSS THE APPALACHIANS OVERNIGHT... REACHING THE EASTERN CAROLINAS AROUND DAYBREAK. IN ADDITION... OVERNIGHT...S/SSW LOW LEVEL JET WILL BE INCREASING TO NEAR 30 KT AT 1200/1500 FT. THIS WILL ALLOW BETTER MOISTURE TO EXPAND NORTHWARD ACROSS THE FORECAST AREA WHICH IS VERY EVIDENT IN MODEL PROFILES. ELEVATED INSTABILITY WILL BE ON THE INCREASE OVERNIGHT AS WELL. THEREFORE...WILL EXPAND HIGH POPS EASTWARD AND ALL THE WAY TO THE COAST THROUGH SUN MORNING. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...BEST RAIN CHANCES OF THE PERIOD COME RIGHT AT THE BEGINNING SUNDAY MORNING. MODERATELY STRONG SHORTWAVE MOVES OFF THE COAST BY 12Z BUT 850MB WARM AIR ADVECTION OVERRUNNING ENE SFC FLOW MAY STILL FIRE SOME ELEVATED CONVECTION. INSTABILITY IS RATHER LACKING SO STRATIFORM RAIN APPEARS JUST AS LIKELY. EXTENSIVE LINGERING CLOUDINESS WILL KEEP HIGHS DOWN BELOW CLIMO. RAIN CHANCES LATER IN THE DAY ARE TOUGH TO FIGURE AS TRIGGERING MECHANISM REALLY SEEMS TO TAPER OFF. MONDAY LOOKS LIKE A MORE TYPICAL JULY DAY. FLOW WILL BE WEAK AT ALL LEVELS AND ONLY MESOSCALE BOUNDARIES WILL SERVE AS A CONVECTIVE TRIGGER. TEMPERATURES WILL BE CLOSE TO NORMAL. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 3 PM SATURDAY...UPPER RIDGING OVER THE SOUTHEAST THROUGH MID WEEK WILL BEGIN TO PULL BACK WEST THU/FRI. STILL NOT SOLD ON THE COLD FRONT REACHING THE AREA...THOUGH THE GFS HAS BEEN CONSISTENT IN DROPPING IT INTO THE CAROLINAS LATE NEXT WEEK. ALTHOUGH UPPER RIDGE RETREATS WEST THERE IS NO REAL UPPER LEVEL PUSH TO HELP GET THE COLD FRONT SOUTH. COMBINED WITH BERMUDA HIGH THINK THE FRONT WILL REMAIN TO THE NORTH THROUGH THE PERIOD. SEA BREEZE AND PIEDMONT TROF WILL BE THE MAIN SOURCES FOR LIFT AND WITH LITTLE TO NO RIDGE ALOFT CONVECTION ALONG THESE BOUNDARIES SHOULD QUICKLY BUILD. KEEPING THE FORECAST DRY EARLY IN THE PERIOD WITH POPS INCREASING TO CHC LATE IN THE WEEK. TEMPERATURES NEAR CLIMO THROUGH THE PERIOD...LOW TO MID 90S AND LOW TO MID 70S. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... AS OF 00Z...QUITE A BIT OF UNCERTAINTY THROUGH THE OVERNIGHT HOURS. FAIRLY STRONG AREA OF OMEGA WILL DROP SOUTHEAST INTO THE REGION BY 03Z. CONVECTION WILL BE MOVING INTO A MORE STABLE AIRMASS...BUT EXPECT ELEVATED CONVECTION TO AFFECT LBT AND FLO THROUGH MOST OF THE OVERNIGHT HOURS...AND THE CONVECTION WILL WEAKEN AS IT TRIES TO MOVE ANY FARTHER EAST. MEANWHILE...WINDS WILL TRY TO SHIFT TO THE NORTHEAST...AS A WEAK WEDGE TRIES TO SET UP. THIS COULD PRODUCE IFR STRATUS...HOWEVER CONFIDENCE IS LOW. CONVECTION WILL FINALLY NEAR THE COAST TOWARD MORNING AS IMPULSE ALSO REACHES THE COAST. ONLY WEAK SHOWERS ARE EXPECTED BY 10Z ALONG THE COAST. MOST OF THE PRECIPITATION WILL EXIT THE COAST BY 14Z WITH IFR/MVFR CEILINGS IMPROVING TO VFR. CONFIDENCE IN THIS TIMING IS ALSO FAIRLY LOW DUE TO THE NAM BRINGING ANOTHER ROUND OF CONVECTION TO THE COAST BY 18Z. NOT SURE IF THE ATMOSPHERE WILL HAVE TIME TO RELOAD. NORTHEAST WINDS WILL RETURN TO A MORE EAST SOUTHEAST DIRECTION BY AROUND NOON. EXTENDED OUTLOOK...ISOLATED THUNDERSTORMS MONDAY AND THURSDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 9 PM SATURDAY...WINDS WILL REMAIN FROM THE E INTO SUN MORNING. HIGH PRESSURE WILL BE CENTERED TO OUR N AND IT IS POSSIBLE THAT PRESSURE GRADIENT WILL GET PINCHED JUST TO OUR N NEAR DAYBREAK. WINDS AND SEAS WILL REMAIN VIRTUALLY UNCHANGED FOR THE REMAINDER OF THE NIGHT AS LOW LEVEL JET REMAINS W OF THE WATERS INTO SUN MORNING. WINDS AND SEAS WILL BE WELL BELOW SMALL CRAFT SHOULD EXERCISE CAUTION CRITERIA. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...EASTERLY WINDS ACROSS THE SOUTHERN ZONES MOST OF SUNDAY WHILE NORTHERN ZONES WILL SEE MORE OF A NORTHEAST FLOW AS THE HIGH HOLDS ON ACRS THE DELMARVA. SPEED CAPPED AT 10 KT FOR THE MOST PART AND SEAS IN THE 2 TO 3 FT RANGE...PREDOMINANTLY WIND WAVE. THE WEAKENING AND LIFTING OUT OF THE HIGH WILL BE VERY GRADUAL ON MONDAY SO THE VEERING OF THE WIND WILL BE RATHER NEGLIGIBLE. WIND SPEEDS AND WAVES GENERALLY UNCHANGED. LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 3 PM SATURDAY...BERMUDA HIGH AND PIEDMONT TROF WILL KEEP SOUTHEAST WINDS IN PLACE THROUGH THE PERIOD. SPEEDS GENERALLY 10 TO 15 KT WITH A MARGINAL INCREASE DURING THE AFTERNOON/EVENING HOURS AS PIEDMONT TROF TIGHTENS AND SEA BREEZE DEVELOPS. SEAS GENERALLY 2 TO 3 FT THROUGH THE PERIOD. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...RJD SHORT TERM...MBB LONG TERM...III AVIATION...43
NWS ILMNWS Office Area Forecast Discussion