-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 210532
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
132 AM EDT TUE MAY 21 2013

.SYNOPSIS...
A DISTURBANCE ALOFT MOVING ACROSS THE AREA WILL MAINTAIN SHOWERS AND
THUNDERSTORMS THROUGH TUESDAY. DRIER AND WARMER WEATHER IS EXPECTED
MID WEEK. A COLD FRONT IS EXPECTED TO APPROACH AND CROSS THE REGION
ON FRIDAY...BRINGING DRIER AND SLIGHTLY COOLER WEATHER INTO THE NEXT
WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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AS OF 130 AM TUESDAY...LATEST SEVERAL HRRR RUNS SHOW INCREASING
POTENTIAL FOR NOCTURNAL CONVECTION LATE TONIGHT...PARTICULARLY IN
THE SC PEE DEE REGION FROM FLORENCE WESTWARD...AND ALSO ACROSS
COASTAL SE NORTH CAROLINA. THAT IS ESSENTIALLY THE ONLY CHANGE TO
THE FORECAST. PREVIOUS DISCUSSION FROM 1100 PM FOLLOWS...

CONVECTIVE ACTIVITY HAS WANED ACROSS THE FA THIS EVENING...NEARLY
IDENTICAL TO WHAT TRANSPIRED SUNDAY EVENING. THE ATM ACROSS THE FA
HAS BEEN ONCE AGAIN TAXED AND BECOME SOMEWHAT STABLE...AND WILL NEED
SOME TIME TO DE-STABILIZE. LIKE LAST EVENING AND OVERNIGHT...THE
DAYS INSOLATION WILL NOT BE AVAILABLE TO AID THIS DESTABILIZATION
PROCESS. WILL HAVE TO RELY...AGAIN LIKE LAST NIGHT...DYNAMICS FROM
WEAK PVA ALOFT AND IN ADDITION...THE SLIGHTLY COLDER TEMPS ALOFT TO
REACH THE FA FROM THE SW-W DIRECTION. LATEST CHS 00Z RAOB INDICATES
SUB -10 C AT 500MB. PWS ACROSS THE FA REMAIN IN THE 1.5 TO 1.7
INCHES...VIA LATEST 00Z RAOB DATA FROM MHX AND CHS. FORECAST STORM
MOTIONS REMAIN SLOW...10 KT OR LESS...WHICH HAS RESULTED IN
SUFFIXING THE CONVECTION WITH HEAVY RAIN POSSIBLE. THE COASTAL
PORTIONS OF THE ILM CWA WILL HAVE THE HIGHEST POPS
ILLUSTRATED...MAINLY OCCURRING DURING THE PRE-DAWN HRS INTO DAYLIGHT
TUESDAY. MIN TEMP FORECAST TWEAKED ACROSS THE FA BUT WILL REMAIN IN
THE MID TO UPPER 60S RANGE PREVIOUSLY FORECAST.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...FORECAST MODELS ARE CONSISTENT IN SHOWING
THE MID LEVEL PATTERN TRANSITIONING FROM WHAT SEEMS LIKE A NEVER
ENDING TROUGH/WEAKNESS TO MORE OF A SOUTHWESTERLY FLOW. THIS IN
RESPONSE TO THE MASSIVE MID LEVEL LOW FINALLY OPENING UP ACROSS
THE NORTHERN PLAINS AND GETTING KICKED OUT.

AT THE SURFACE...BERMUDA HIGH PRESSURE WILL REMAIN THE MAIN PLAYER
ALTHOUGH THIS HAS LITTLE IMPACT OR CHANGE ON PREVAILING CONDITIONS
AS THIS HAS BEEN SECONDARY THE PAST FEW DAYS. POPS REMAIN ON A
DIURNAL CYCLE ALTHOUGH LOWER THROUGH THE PERIOD AS THE MID LEVEL
CATALYST IS ALL BUT REMOVED. HAVE OPTED FOR THE WARMER MAV NUMBERS
FOR TEMPERATURES THROUGH THE PERIOD.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...ONE LAST DAY OF WARM AND HUMID CONDITIONS ON
THURSDAY AS UPPER TROUGH AND SURFACE COLD FRONT BEAR DOWN ON THE
REGION FROM THE NW. SOMEWHAT SURPRISINGLY MODELS ARE GRAVITATING
TOWARDS A QUICKER SOLUTION AND THE FRONT MAY PUSH THROUGH TUESDAY
NIGHT. AHEAD OF IT SW FLOW AND HEIGHT FALLS SHOULD YIELD BETTER THAN
AVERAGE COVERAGE OF CONVECTION AND WITH A LARGELY PINNED SEABREEZE
THERE MAY BE NO PREFERRED LOCATION FOR MEASURABLE RAINFALL ESP THIS
FAR OUT IN TIME. SYSTEM WILL MOVE A LITTLE BIT SLOWLY OWING TO THE
STRENGTH OF THE DOWNSTREAM RIDGING AND RAIN CHANCES MAY LINGER INTO
FRIDAY ESPECIALLY ALONG THE COAST. MODEST COOLING AND STRONG DRYING
WILL THEN FOLLOW FOR THE WEEKEND AND SOME VERY COMFORTABLE AND
PLEASANT WEATHER APPEARS TO BE ON TAP. DAYTIME DEVIATIONS FROM CLIMO
TEMPS SHOULD BE RATHER SMALL BUT THE NIGHTS MAY TURN COOLISH DUE TO
THE DRYING. THE POST-FRONTAL HIGH MAY MOVE OFF THE COAST ON MONDAY
ALLOWING FOR AN UPTICK IN THE DEWPOINTS.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
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AS OF 06Z...PLENTIFUL LOW-LEVEL MOISTURE HAS LED TO DEVELOPMENT OF
IFR STRATUS CEILINGS INLAND WHICH MAY CONTINUE THROUGH DAYBREAK. THE
ONLY POTENTIAL TO SCOUR OUT THESE LOW CIGS EARLIER WILL BE IF
CONVECTIVE SHOWERS OR T-STORMS CAN DEVELOP ACROSS THE SC PEE DEE
REGION AS SHOWN ON THE LATEST SEVERAL RUNS OF THE HRRR MODEL. THIS
COULD LEAD TO ENOUGH DISTURBANCE OF THE STABLE LOW-LEVEL INVERSION
TO LIFT CEILINGS AT KFLO TEMPORARILY INTO THE VFR RANGE SHORTLY
BEFORE DAYBREAK. ALONG THE COAST VFR CONDITIONS SHOULD PREVAIL
THROUGH DAYBREAK WITH THE POSSIBLE EXCEPTION OF SCATTERED SHOWERS
ADVECTING ONSHORE OFF THE ATLANTIC OCEAN...MAINLY AFTER 09Z...WITH
ACCOMPANYING MVFR CIGS.

AFTER DAYBREAK A TYPICAL SUMMER AIRMASS WILL YIELD SCATTERED SHOWERS
AND THUNDERSTORMS DURING THE HEAT OF THE DAY. PREVAILING SOUTH WINDS
SHOULD SWEEP MOST OF THE ACTIVITY AWAY FROM THE COAST BY
MID-AFTERNOON WITH FLO/LBT SEEING THE BEST POTENTIAL OF VSBY
RESTRICTIONS IN SHOWERS OR STORMS.

EXTENDED OUTLOOK...SCATTERED SHOWERS/TSTMS WITH TEMPO MVFR ON
TUESDAY. CHANCE OF SHOWERS THURSDAY THROUGH EARLY FRIDAY. OTHERWISE
VFR.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM TUESDAY...NO SIGNIFICANT CHANGES TO THE FORECAST NEEDED
EARLY THIS MORNING. PREVIOUS DISCUSSION FROM 1100 PM FOLLOWS...

SSE-SSW WINDS TO REMAIN 10 TO OCCASIONALLY 15 KT OVERNIGHT. THIS IN
RESPONSE TO RIDGING FROM THE WESTERN ATLANTIC HIGH. SOUTH OF THE SFC
RIDGING...AN ESE-SSE FLOW EXTENDS FROM WELL OFFSHORE AND ACROSS A
DECENT FETCH LEADING UP TO THE SE U.S. COAST. THIS HAS RESULTED IN
AN EVOLVING AND BUILDING SE GROUND SWELL AT 2 TO 4 FT EXHIBITING 7
TO 8 SECOND PERIODS...JUST PRIOR TO ENTERING THE ILM COASTAL WATERS.
SEE LATEST 41013 BUOY DATA. COMBINED WITH 3 TO 5 SECOND PERIOD
LOCALLY PRODUCED WIND DRIVEN WAVES...SIGNIFICANT SEAS ACROSS THE
COASTAL WATERS WILL RUN A SOLID 3 TO 4 FT...WITH 5 FOOTERS POSSIBLE
ACROSS THE OUTER WATERS OFF CAPE FEAR. OVERALL...THE WIND AND
SIGNIFICANT SEAS FORECAST REMAINS ON TRACK. ONLY UPDATE WAS TO
RESTRUCTURE POPS ACROSS THE COASTAL WATERS TO ACCOUNT FOR THE
DIMINISHED CONVECTION THIS EVENING...FOLLOWED BY AN INCREASING
COVERAGE TOWARD DAYBREAK TUE.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...BERMUDA HIGH PRESSURE REMAINS THE MAIN FEATURE
FOR THE COASTAL WATERS WITH A SOUTHERLY FLOW EXPECTED TO CONTINUE
THROUGH THE PERIOD. SPEEDS WILL CONTINUE IN A 10-15 KNOT RANGE
WITH A SLIGHT INCREASE CLOSER TO THE COAST EACH LATE MORNING AND
AFTERNOON WITH THE SEA BREEZE. THE LATEST RUN OF SWAN REMAINS
CONSISTENT WITH 2-4 FOOT SEAS.

LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 PM MONDAY...COAST WILL LIE BETWEEN STRONG HIGH PRESSURE
ACROSS THE WEST-CENTRAL ATLANTIC AND APPROACHING COLD FRONT TO THE
NW. THE LATTER WILL BE DISPLACED EASTWARD OF THE MORE TYPICAL
BERMUDA HIGH POSITION WHICH WILL ACT TO EASE THE GRADIENT OTHERWISE
EXPECTED GIVEN SUCH A LARGE ANTICYCLONE. THE RESULTING SWELL ENERGY
COULD BRING SOME SCEC-WORTHY 5 FT SEAS TO PART OF THE AREA MAINLY
NORTHERN ZONES. COLD FRONT NOW APPEARS FASTER THAN PREVIOUSLY
THOUGHT AND SHOULD YIELD VEERING WINDS BY FRIDAY MORNING WITH A TURN
TO OFFSHORE. THE OFFSHORE FETCH AND SWELL DISRUPTION WILL LEAD TO
LOWER SEAS ON FRIDAY BUT THEN THE ENSUING PUSH OF DRY HIGH PRESSURE
COULD TIGHTEN THE GRADIENT AGAIN TO WHERE HEADLINES TOUGH TO RULE
OUT.
-- End Changed Discussion --

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...SHK
NEAR TERM...DCH/TRA
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...SGL/TRA