AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
304 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 3 PM THURSDAY...CONVECTION BEGINNING TO BECOME MORE
WIDESPREAD ALONG THE SEA BREEZE AS EXPECTED...AND THIS WILL
GRADUALLY WORK INLAND DURING THE NEXT FEW HOURS...CONCURRENT WITH
THE DEVELOPMENT OF STORMS ACROSS THE PIEDMONT. LATEST RUC
SOUNDINGS STILL SHOW VERY FAVORABLE PARAMETERS FOR HEAVY RAIN IN
THUNDERSTORMS...WITH CAPE OVER 2500 J/KG...PWATS AROUND 2
INCHES...WARM CLOUD DEPTH TO NEARLY 11 KFT...AND SLOW STORM
MOTIONS...SO WILL CONTINUE LIKELY POP INLAND WHERE OUTFLOWS AND
THESE BOUNDARIES WILL FIRE TSTMS ALL AFTN. THE COASTAL LOCATIONS
WILL GRADUALLY SEE DECREASING COVERAGE OF TSTMS AS THE SEA BREEZE
PUSHES WESTWARD. TRICKY TEMP FORECAST DUE TO RAIN COOLING OF
AIR...BUT ENOUGH INSOLATION TO THEN REHEAT THE SURFACE...SO TEMPS
WILL FLUCTUATE QUITE DRAMATICALLY DURING THE NEXT FEW HOURS IN
LOCATIONS THAT DO RECEIVE RAINFALL.

LATEST WV IMAGERY IS IMPRESSIVE ACROSS THE GOM WHERE HPC NOW HAS
ANALYZED A CLOSED LOW WEST OF THE FLORIDA KEYS. LATEST NAM HAS COME
INTO LINE WITH OTHER GUIDANCE...BRINGING A TROUGH/MOISTURE PLUME
ALONG THE SE COAST LATE TONIGHT. HAVE CONTINUED LIKELY POP NEAR THE
COAST AFTER MIDNIGHT...AND BACKED THE CHANCE POP FURTHER WEST TO
ACCOUNT FOR THIS WESTWARD SHIFT AND DEPICTION OF PRECIP ON HIGH RES
MODELS. WITH PWATS RISING TO NEARLY 2.5 INCHES...BELIEVE THE BEST
RAINFALL AT THE COAST MAY BE LATE TONIGHT. HOWEVER...CONFIDENCE IS A
BIT LOWER DUE TO UNCERTAINTY IN PLACEMENT OF BEST MOISTURE FETCH.

HIGHS TODAY WILL BE IN THE MID 80S NEAR THE COAST...LOW 90S INLAND.
CLOUD COVER AND VERY HIGH TD/S WILL LIMIT MINS FROM FALLING TOO FAR
TONIGHT...WITH MID TO UPPER 70S EXPECTED AT THE COAST...TO AROUND 72
IN THE COOLEST SPOTS.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...NOT TOO CONFIDENT IN THE DETAILS BUT THE
BOTTOM LINE APPEARS TO BE A WET FORECAST. NOT NEARLY AS BULLISH ON
THE IDEA OF A TROPICAL LOW RIDING UP THE COAST AS PORTRAYED IN THE
NAM. HOWEVER...REGARDLESS OF THE SFC PATTERN...THE COMBINATION OF
A JUICY TROPICAL AIR MASS AND UPPER TROFINESS COULD PROMOTE HEAVY
RAINFALL...ESPECIALLY FRIDAY AFTERNOON.

GIVEN THAT THIS FORECAST FOLLOWS THE GFS SOLUTION...WE HAVE
FOLLOWED THE GFS MOS TEMPS WHICH ARE ACTUALLY ON THE LOW SIDE OF
CLIMO FOR FRIDAY MAX TEMP...AND NEAR OR ABOVE NORMAL BEYOND THAT.

&&

.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 /18Z THURSDAY THROUGH TUESDAY/...
AS OF 18Z...HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE VALID
PERIOD...WITH EXCEPTION OF SCATTERED SHOWERS AND THUNDERSTORMS
TODAY...AND POTENTIAL MVFR CIG RESTRICTIONS DUE TO FOG EARLY
FRIDAY MORNING.

A FEW SHOWERS THAT TRIGGERED EARLIER TODAY HAVE ALREADY TAPERED OFF.
EXPECT SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THE REST OF
TODAY...THUS HAVE INCLUDED VCSH/VCTS AT ALL TERMINALS. GIVEN LOW
CONFIDENCE REGARDING THE OCCURRENCE OF THIS ACTIVITY...HAVE NOT
INCLUDED ANY FLIGHT RESTRICTIONS ATTM. HOWEVER...BRIEF PERIODS OF
REDUCED VSBYS...HEAVY RAIN AND WIND GUSTS WILL BE POSSIBLE WITH
STRONGER STORMS. EXPECT SHRA/TSRA ACTIVITY TO DISSIPATE BY LATE
EVENING. OVERNIGHT...CLOUDS WILL STICK AROUND. ATTM CONFIDENCE IS
LOW REGARDING ANY MVFR/IFR RESTRICTIONS FRIDAY MORNING.
HOWEVER...GIVEN LOW DEWPOINT DEPRESSIONS AT THE INLAND
TERMINALS...AND THE POTENTIAL FOR A LLVL CLOUD DECK GIVEN ABUNDANT
MOISTURE...CANNOT RULE OUT THE POSSIBILITY OF OCCURRENCE. FOR
NOW...HAVE INCLUDED MVFR CIG RESTRICTIONS AT INLAND TERMINALS.

ADDITIONALLY...SCATTERED SHOWERS AND TSTMS MAY ADVECT INLAND FROM
THE WATERS BEGINNING LATE TONIGHT AND PERSISTING THROUGH THE END OF
THIS VALID PERIOD. FOR NOW HAVE INDICATED SCT AT MVFR LEVEL WITH
VCSH AND WILL UPDATE WITH LATER ISSUANCES.

SOUTHWEST WINDS WILL GRADUALLY SHIFT MORE SOUTH/SOUTHWEST BY THIS
AFTERNOON. NOT EXPECTING A WELL-DEFINED SEA BREEZE TODAY...BUT WINDS
WILL SLIGHTLY SHIFT MORE TOWARDS THE SOUTH...WITH POSSIBLE GUSTS UP
18KT AT THE COAST. OVERNIGHT...WIND SPEEDS WILL DECREASE WITH A
CONTINUED SOUTHWEST FLOW.

EXTENDED OUTLOOK...WIDESPREAD SHOWERS AND THUNDERSTORMS POSSIBLE
THROUGH THE WEEKEND. DECREASING CHANCES FOR CONVECTION BY EARLY NEXT
WEEK.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM THURSDAY...SOUTHERLY FLOW WILL CONTINUE...INCREASING TO
15 KTS THIS AFTN/EVE AS GRADIENT TIGHTENS. MERGING FETCH BETWEEN
PERSISTENT BERMUDA HIGH AND DEVELOPING TROPICAL WAVE NEAR FLORIDA
WILL GRADUALLY ENHANCE SEAS TODAY. SEAS ALREADY 3 TO 4 FT WILL
INCREASE TO 4 TO 5 FT BY THIS EVE...WITH A FEW 6 FT SEAS POSSIBLE
IN THE 30 TO 40 NM RANGE...AND WIND WAVES DOMINATING THE WAVE
SPECTRUM. LATE IN THE PERIOD A TROUGH OF LOW PRESSURE WILL MOVE
NEAR THE COAST BRINGING THE POTENTIAL FOR WIDESPREAD SHOWERS AND
THUNDERSTORMS TONIGHT...WITH CONFUSED SEAS LIKELY NEAR ANY
THUNDERSTORM.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...SOUTHERLY FLOW AROUND THE BERMUDA HIGH WILL
PERSIST FOR MUCH OF THE PERIOD. WIND SPEEDS WILL BE FAIRLY MODEST
LOCALLY...WITH ONLY AN OUTSIDE CHANCE OF 15-20 KT...BUT A WIDE-
OPEN SSE FETCH EAST OF THE BAHAMAS WILL SEND A DECENT SWELL IN OUR
DIRECTION. EXPECT SEAS TO REACH 4-5 FT ALONG FRYING PAN SHOALS ON
SATURDAY...WITH PRETTY WIDESPREAD 3-4 FT WITHIN 20 NM.

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.

&&

$$
NEAR TERM...JDW