AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 739 PM EDT THU JUL 7 2011 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL MAINTAIN A MOIST SOUTHERLY FLOW ACROSS THE EASTERN CAROLINAS INTO THE WEEKEND. A WEAK COLD FRONT MAY REACH THE AREA SATURDAY NIGHT BEFORE DISSIPATING ON SUNDAY. TROPICAL-LIKE 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/... AS OF 730 PM THURSDAY...A BREAK IN THE SUBTROPICAL RIDGE AXIS ACROSS THE SOUTHEASTERN U.S. HAS ALLOWED DEEP TROPICAL MOISTURE TO POOL ACROSS THE AREA. PRECIPITABLE WATER VALUES AROUND 2.00 INCHES AND WIDESPREAD MODERATE INSTABILITY ARE TYPICAL FOR A TROPICAL AIRMASS LIKE THIS ONE. THE SEABREEZE BOUNDARY MERGED WITH CONVECTIVE OUTFLOWS EARLIER AND HAS PUSHED WEST...NEARLY THROUGH OUR ENTIRE FORECAST AREA. THUNDERSTORMS REMAIN POSSIBLE ACROSS PORTIONS OF THE PEE DEE REGION OVER THE NEXT 2-3 HOURS WHERE MERGING CELL CLUSTERS ACROSS THE SANDHILLS AND SC MIDLANDS COULD PUSH BACK TO THE EAST DUE TO COLD-POOL PROPAGATION EFFECTS. AT THE SURFACE A TROPICAL WAVE THAT CROSSED FLORIDA TODAY IS NOW INTERACTING WITH AN UPPER LOW OVER THE CENTRAL GULF OF MEXICO. ALTHOUGH THE WAVE ITSELF WILL NOT PUSH ACROSS THE CAROLINAS THERE HAS BEEN A SUBTLE BACKING OF THE LOW-LEVEL FLOW AND A FURTHER INCREASE IN LOW-LEVEL MOISTURE WITH THE CLOSE APPROACH OF THIS SYSTEM. DEWPOINTS ARE IN THE MID TO UPPER 70S ALONG THE COAST AND OFFSHORE. ONCE CONVECTION DIES DOWN INLAND WE EXPECT THE FOCUS TO SHIFT OFFSHORE IN A TYPICAL DIURNAL FASHION...WITH INCREASING COVERAGE OF SHOWERS AND T-STORMS TOWARD AND AFTER MIDNIGHT. 700 MB WINDS ARE ESSENTIALLY SOUTHERLY WHICH WILL HELP PUSH ANY OFFSHORE ACTIVITY ONSHORE...WITH THE CAPE FEAR AREA IN THE HIGHEST RISK OF SEEING SHOWERS/STORMS AFTER MIDNIGHT. LOWS TONIGHT WILL REMAIN QUITE WARM GIVEN THE AMOUNT OF MOISTURE IN THE AIR...AND THE PRESENCE OF A WEAK LOW-LEVEL JET WHICH SHOULD HELP KEEP THE BOUNDARY LAYER FROM DECOUPLING OVERNIGHT. WE ARE EXPECTING 72-76 INLAND...WITH UPPER 70S WITHIN A FEW MILES OF THE BEACHES. UNLESS SIGNIFICANT AREAS OF HEAVY RAIN DEVELOP NEAR SHORE SOME BEACHES MIGHT NOT DIP BELOW 80 DEGREES TONIGHT. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 PM THURSDAY...TROPICAL-LIKE MOISTURE STREAMING NORTHWARD ACROSS THE EASTERN CAROLINAS SHOULD BRING AN INCREASING RISK FOR SHOWERS AND THUNDERSTORMS. THE PRIMARY CHARACTERISTIC OF THIS CONVECTION WILL BE VERY HEAVY RAIN WITH PRECIPITABLE WATER VALUES AROUND 2.25 INCHES. THE RISK FOR AT LEAST MINOR FLOODING WILL BE ON THE INCREASE...ESPECIALLY IN THOSE AREAS WHERE HEAVY RAIN HAS OCCURRED OVER THE LAST FEW DAYS. A WET MICROBURST WILL BE CAPABLE OF BRINGING STRONG WINDS TO THE SURFACE...ESPECIALLY FRI AFTERNOON. A WEAK TROUGH WILL LIMP INTO THE AREA LATE SAT NIGHT. MAY SEE LOW STRATUS OR FOG DEVELOP AS WEAK FRONTAL BOUNDARY LIMPS INTO THE AREA LATE SAT NIGHT AND SUN MORNING...SHIFTING LIGHT WINDS TO NORTHERLY. THE LARGEST WILDFIRES REMAIN ACROSS NORTHERN PENDER COUNTY...IN THE HOLLY SHELTER GAME LAND AND NEAR THE BLADEN-CUMBERLAND COUNTY LINE. IF THESE NORTHERLY WINDS DO MATERIALIZE...SMOKE PLUMES WILL CHANGE THEIR ORIENTATION...BLOWING SMOKE FROM N TO S...INSTEAD OF FROM S TO N WHICH HAS BEEN THE CASE FOR MANY DAYS NOW. GIVEN THE EXTENT OF CLOUD COVER EXPECTED...AND CONSIDERING THE DEPTH OF MOISTURE...TENDED TO GO ABOVE GUIDANCE ON MINIMUMS AND AT OR BELOW THE COOLEST GUIDANCE FOR MAXIMUMS. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 3 PM THURSDAY...MID LEVEL RIDGE BUILDS OVER TN AND OHIO VALLEY ON SUNDAY AS WELL AS ACRS THE BAHAMAS. THERE IS SOME MODEL AGREEMENT THAT A SHORTWAVE SLIDES SOUTHWARD BETWEEN THE TWO AND THIS MAY BRING ONE LAST DAY OF SLIGHTLY ENHANCED RAINFALL CHANCES BEFORE THE LONG TERM SHIFTS LARGELY BACK TO A FORECAST OF CLIMATOLOGY. THIS UPPER FORCING WILL BE BOOSTED BY A SURFACE TROUGH LINGERING JUST INLAND FROM THE COAST AS WELL AS PLENTIFUL OUTFLOW BOUNDARIES FROM SATURDAYS POTENTIALLY ACTIVE DAY OF CONVECTION. AFTERNOON HIGHS WILL BE NEAR CLIMO OR JUST A FEW DEGREES BELOW ON ACCOUNT OF THE POSSIBILITY OF WIDESPREAD CLOUD COVER. AS THIS MID LEVEL FEATURE MOVES OFF INTO THE GOMEX HEIGHTS RISE LOCALLY AND SOME DRYING SOUTH OCCUR. THERE WILL BE LITTLE CHANGE IN SURFACE AND LOW LEVEL AIRMASS...AS TYPICAL FOR JULY. THIS WILL STILL LEAVE THE DOOR OPEN FOR VERY ISOLATED COVERAGE OF AFTERNOON THUNDERSTORMS ALONG MESOSCALE BOUNDARIES AND TEMPERATURES WILL AVERAGE A FEW DEGREES ABOVE CLIMATOLOGY MONDAY AND TUESDAY. MODEL AGREEMENT IN DEPICTING A COLD FRONT APPROACHING AND PERHAPS EVEN TRAVERSING THE AREA WEDNESDAY OR WEDNESDAY NIGHT APPEARS TO WARRANT SOME INCREASED CLOUD COVER AND RAIN CHANCES. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... AS OF 00Z...MODERATE CONFIDENCE IN FORECAST DUE TO CONVECTION AND POTENTIAL RESTRICTIONS OVERNIGHT. CURRENT RADAR IS SHOWING SHOWERS AND THUNDERSTORMS ACROSS THE AREA FIZZLING OUT WITH LOSS OF INSOLATION. WITH MODELS SHOWING COASTAL LOW DEVELOPING LATE TONIGHT AND AMPLE MOISTURE BEING ADVECTED IN...SHOWERS WILL LIKELY DEVELOP AGAIN OVERNIGHT. SHOWER ACTIVITY WILL AFFECT THE COASTAL TERMINALS AND THEN MOVE INLAND BY MORNING. ANOTHER CONCERN OVERNIGHT WOULD BE POTENTIAL STRATUS. GIVEN A DECENT NOCTURNAL LLJ... AND SEEING THAT NO SIGNIFICANT RAINFALL OCCURRED AT THE TERMINALS THUS FAR...STRATUS OVERNIGHT SEEMS MORE LIKELY THAN FOG. WITH GOOD LOW LEVEL MOISTURE VIA SOUTHERLY FLOW...AM EXPECTING CIGS TO DEVELOP SHORTLY BEFORE DAYBREAK INLAND. AFTER SUNRISE...CIGS SHOULD LIFT AND VFR WILL PREVAIL. GIVEN SIMILAR SYNOPTIC CONDITIONS...THUNDERSTORMS WILL REDEVELOP IN THE AFTERNOON. EXPECT STRONG AND GUSTY WINDS AND BRIEF PERIODS OF REDUCED VSBY WITHIN HEAVIEST RAINFALL. ACTIVITY WILL LIKELY PERSIST THROUGH THE END OF THE VALID PERIOD. EXPECT SOUTHERLY FLOW THROUGHOUT THE DAY WITH SPEEDS AROUND 10-15 KNOTS...WITH GUSTS UP TO 20 KNOTS AT THE COAST AS THE PRESSURE GRADIENT TIGHTENS. EXTENDED OUTLOOK...WIDESPREAD SHOWERS AND THUNDERSTORMS LIKELY THROUGHOUT THE WEEKEND. PRECIP CHANCES DECREASE EARLY NEXT WEEK. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 730 PM THURSDAY...BERMUDA HIGH PRESSURE WELL OFFSHORE IS STILL PRODUCING A GENTLE SOUTH WIND ACROSS THE AREA. THIS IS BRINGING A TROPICAL AIRMASS NORTHWARD FROM THE CARIBBEAN VIA THE BAHAMAS. SCATTERED TROPICAL DOWNPOURS ALREADY ONGOING OVER THE GULF STREAM WILL SPREAD INTO THE COASTAL WATERS LATE THIS EVENING...WITH SHORT-LIVED VISIBILITY RESTRICTIONS AND SOME LIGHTNING POSSIBLE. BOTH THE NAM AND GFS MODELS SHOW SIMILAR WIND DIRECTIONS TONIGHT (SOUTH) BUT DIFFER SOMEWHAT ON THE WIND SPEEDS EXPECTED. THE GFS IS STRONGER...BRINGING WINDS AT THE FRYING PAN SHOALS BUOY UP TO 19 KNOTS BY MIDNIGHT. WE PREFER THIS STRONGER GUIDANCE...WHICH BRINGS A SOLID 12-16 KNOT WIND ACROSS MOST OF OUR COASTAL WATERS BY MIDNIGHT. SEAS AVERAGE 3-4 FT CURRENTLY...WITH THE BULK OF THE WAVE ENERGY EMBODIED IN A 8-9 SECOND SOUTHEAST SWELL. SOME 5-FOOT SEAS MAY DEVELOP AT AND BEYOND 20 MILES FROM SHORE TONIGHT...ESPECIALLY NEAR CAPE FEAR AND EAST OF GEORGETOWN/WINYAH BAY. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 PM THURSDAY...WINDS FRI WILL BE FROM THE SSW...VEERING TO SW FRI NIGHT INTO SAT NIGHT AND THEN BECOMING LIGHT AND VARIABLE OR EVEN FOR A TIME SHIFTING TO A NORTHERLY DIRECTION LATE SAT NIGHT AND SUN MORNING. STRONGEST WINDS THIS PERIOD WILL OCCUR FRI AFTERNOON INTO SAT AFTERNOON COINCIDENT WITH TIGHTEST PRESSURE GRADIENT AHEAD OF UPSTREAM TROUGH. PRESSURE GRADIENT WILL THEN RELAX GIVEN THE PROXIMITY OF TROUGH SAT NIGHT. THE WAVE SPECTRUM WILL BE DOMINATED BY WIND WAVES FOR MOST OF THE PERIOD...HOWEVER A SE SWELL WILL BE PRESENT. WE WILL BE CLOSE TO SMALL CRAFT ADVISORY CONDITIONS FRI AND FRI NIGHT AS SEAS BUILD. WILL CAP SEAS AT 5 FT WITHIN 20 NM...ALTHOUGH 6 FT SEAS ARE FORECAST JUST BEYOND 20 NM. HIGHEST WINDS WILL BE IN 15 TO 20 KT RANGE...ALTHOUGH SOME GUSTS NEAR 25 KT ARE POSSIBLE LATER FRI AND FRI NIGHT. AT THIS TIME...IT APPEARS CONDITIONS WILL REACH SMALL CRAFT SHOULD EXERCISE CAUTION LEVELS...BUT FALL JUST SHORT OF SMALL CRAFT ADVISORY LEVELS. LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 3 PM THURSDAY...A WEAK SURFACE TROUGH JUST WEST OF THE COASTAL WATERS PAIRED WITH A SPRAWLING HIGH IN THE WEST ATLANTIC WILL BRING A SOUTHERLY COMPONENT TO THE WIND FLOW REGIME. THE PRESENCE OF THE TROUGH WILL PUSH THE BEST GRADIENT OUT TO SEA AND WIND WILL REMAIN QUITE LIGHT. BY MONDAY THIS BOUNDARY WILL WASH OUT LEAVING A MORE TYPICAL SOUTHWESTERLY GRADIENT WIND INDUCED BY THE STALWART BERMUDA HIGH. THE DEVELOPMENT OF A PIEDMONT TROUGH ON TUESDAY INCREASE THE WIND SPEED BY JUST A FEW KNOTS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$