FXUS62 KILM 060209
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1009 PM EDT SAT JUL 5 2008

.SYNOPSIS...
SEASONABLY WARM AND HUMID CONDITIONS WILL PERSIST THROUGH THE 
NEXT SEVEN DAYS AS HIGH PRESSURE REMAINS ANCHORED OFFSHORE. SHOWERS 
AND THUNDERSTORMS WILL DEVELOP EACH AFTERNOON...BUT SHOULD REMAIN
MOST NUMEROUS THROUGH MONDAY AS SEVERAL WEAK UPPER LEVEL 
DISTURBANCES MOVE ACROSS THE CAROLINAS.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY/...
AS OF 10 PM SATURDAY...CONVECTIVE ACTIVITY HAS DIED DOWN OVER THE
ILM CWA...WITH JUST LINGERING STRATIFORM PRECIP IN A FEW PLACES.
ONE LAST CLUSTER OF STORMS TRIED TO MOVE OUT OF THE NORTH MIDLANDS
OF SC...BUT NOW DISSIPATING ON OUR DOORSTEP AS THE LOCAL
ENVIRONMENT HAS BEEN WORKED OVER.  THUNDERSTORMS ARE STILL
SUSTAINING THEMSELVES TO OUR NORTH...WHERE DYNAMICS ARE MOVE
FAVORABLE.

EVEN WITH PLENTY OF MOISTURE AND AN UPPER IMPULSE LIFTING OUT OF
THE DEEP SOUTH OVERNIGHT...STABILITY WILL LIMIT CONVECTIVE
POTENTIAL OVER LAND. THEREFORE WILL SCALE POPS BACK TO SLIGHT/LOW
CHANCE FOR THE REMAINDER OF THE NIGHT...AND NOT MUCH QPF TO GO
WITH IT. MAYBE SOME CONCERN WITH FOG POTENTIAL IN THE AREAS THAT
RECEIVED HEAVY RAINFALL FROM STORMS THIS AFTERNOON/EVENING...BUT
PLENTY OF DEBRIS CLOUDINESS TO LIMIT RADIATIONAL COOLING. 
 
&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...A MID-LEVEL TROUGH EXTENDING SOUTH FROM THE
EASTERN GREAT LAKES INTO GEORGIA WILL PROVIDE THE NEEDED LIFT AND
COOLING ALOFT TO IGNITE SEVERAL WAVES OF IMPRESSIVE THUNDERSTORMS
OVER THE NEXT COUPLE OF DAYS. AS PRECIPITABLE WATER VALUES REACH
OR EXCEED 2 INCHES SOME LOCATIONS ACROSS THE EASTERN CAROLINAS
ARE GOING TO PICK UP SEVERAL INCHES OF RAIN...WITH WIDESPREAD
AVERAGE AMOUNTS 0.50-0.75 INCHES. SURFACE-BASED CAPE OVER THE NEXT
FEW DAYS FROM VIRTUALLY ANY MODEL FLUCTUATES BETWEEN 1500-3500
J/KG DEPENDING ON TIME OF DAY AND LOCATION RELATIVE TO THE COAST.

TIMING OF INDIVIDUAL WEAK DISTURBANCES ALOFT IS KEY TO THE
RAINFALL FORECAST. THE MODELS AGREE ONE SUCH DISTURBANCE WILL MOVE
NORTH ALONG THE COAST JUST AFTER SUNRISE SUNDAY. THIS COULD LEAD
TO CONVECTION EARLY IN THE DAY IN THE CAPE FEAR REGION. A SECOND
DISTURBANCE APPEARS TO MOVE EAST THROUGH THE CENTRAL CAROLINAS
SUNDAY AFTERNOON. THERE IS LESS AGREEMENT SUNDAY NIGHT INTO MONDAY
WITH THE DISTURBANCES ALOFT...BUT POPS REMAIN HIGH (50-70%) AGAIN
ON MONDAY...WITH THE AXIS OF HIGHEST CHANCES POSSIBLY SHIFTING A
LITTLE CLOSER TO THE COAST.

STORM MOTION WILL INCREASE TO AROUND 20 KT SUNDAY INTO MONDAY.
NEARLY UNIDIRECTIONAL WIND PROFILES WILL MINIMIZE SEVERE WEATHER
RISK...BUT HEAVY RAINFALL PRODUCING LOCALIZED FLOODING OR AN
ISOLATED WET MICROBURST CANNOT BE RULED OUT. DIURNAL TEMPERATURE RANGES
WILL BE CONSTRICTED WITH ALL THE DEEP MOISTURE IN PLACE. LOWS
SHOULD RANGE FROM 71-75 WITH AFTERNOON HIGHS 85-89 BOTH DAYS.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 3 PM SATURDAY...ONCE AGAIN NOT MUCH CHANGE IN THE EXTENDED 
FORECAST THIS AFTERNOON AS BERMUDA HIGH PRESSURE WILL BE THE MAIN
FOCUS THROUGH THURSDAY. A FRONT WILL PUSH SOUTH INTO THE AREA
FRIDAY AS THE MIDLEVEL FLOW VEERS TO NORTHWEST VIA A SUBTLE TROUGH
AND THE MIDLEVEL RIDGE RETROGRADING TO THE WEST.

WITH PRECIPITABLE WATERS HOVERING NEAR TWO INCHES THROUGHOUT...WILL 
KEEP A DIURNAL PATTERN OF SHOWERS AND THUNDERSTORMS...MAXIMIZED FROM 
THE EARLY AFTERNOON THROUGH EVENING HOURS FOR EACH DAY. HAVE TIMED 
THE HIGHEST POPS FOR FRIDAY AS OMEGA FIELDS HAVE GOOD LOW AND MID 
LEVEL COUPLING WITH THE FRONT AND DIVERGENCE ALOFT.

TIME HEIGHTS SHOW DRAMATIC DRYING THROUGH ALL LEVELS SATURDAY BUT 
CONFIDENCE IS LOW IN MOVING THE FRONT MUCH OFF THE COAST AS THE 
ATTENDANT TROUGH IS WEAK. WILL MAINTAIN SLIGHT CHANCE POPS FOR 
SATURDAY.

NO CHANGE IN TEMPERATURE FORECAST.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
CONVECTION WILL BE STUBBORN TO WIND DOWN THROUGH 02Z...WITH A WEAK 
SHORTWAVE MOVING THROUGH THE NORTHERN PORTION OF THE CWA FROM 
03-07Z...AFFECTING LBT AND PERHAPS ILM AFTER MIDNIGHT. FOG WILL BE A 
MINOR PLAYER...WITH MVFR A DECENT BET. DO NOT THINK FOG WILL LOWER 
TO IFR/LIFR DUE TO CLOUD COVER AND A BIT OF INSTABILITY LEFT OVER.

LOOK FOR CONVECTION TO FIRE FIRST ALONG THE RESULTANT AROUND MIDDAY 
SUNDAY...WITH STRONG THUNDERSTORMS LIKELY AGAIN TOWARD THE WEST AFTER 19Z. 
TERMINALS WILL SEE IFR/LIFR VISIBILITIES...BUT FOR ONLY A FEW 
MINUTES...SO LEFT THE PREVAILING HIGHER THAN THAT. CONTINUED 
SOUTHERLY FLOW THROUGH THE PERIOD.

OUTLOOK SUNDAY EVENING THROUGH TUESDAY...SHOWERS AND THUNDERSTORMS 
WILL BE NUMEROUS INTO SUNDAY EVENING THROUGH TUESDAY....WITH BEST 
COVERAGE JUST AFTER MAX HEATING EACH DAY. MVFR TO IFR CONDITIONS 
POSSIBLE IN THUNDERSTORMS SUNDAY EVENING THROUGH TUESDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 PM SATURDAY...SEABREEZE CIRCULATION WEAKENED MORE QUICKLY
TONIGHT...WITH MOST OF THE BUOY OBS SHOWING 10-15 KT WINDS. THINK
THAT WINDS WILL REMAIN A BIT WEAKER THAN LAST NIGHT...SO WILL HOLD
SPEEDS IN THAT REALM THRU THE NIGHT. SEAS ONLY RUNNING 3 FT...A
SOLID FOOT LESS THAN WW3 GUIDANCE. THE ONLY FACTOR REALLY IN
FAVOR OF BUILDING SEAS WILL BE THE CONVECTION THAT HAS ALREADY LIT
UP OVER THE GULF STREAM...BUT DO NOT FIGURE THAT WARRANTS MENTION
OF ORGANIZED 5 FOOTERS. WILL REMOVE THE SCEC AND ALLOW THE HIGHER
NEAR TSTMS WORDING TO COVER ANY OF THAT...OTHERWISE 3-4 FT SHOULD
COVER THE SEA STATE OVERNIGHT.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...BERMUDA HIGH PRESSURE WILL CONTINUE TO FEED
A SOUTHERLY FLOW ACROSS THE AREA SUNDAY THROUGH MONDAY NIGHT. A
SERIES OF UPPER LEVEL DISTURBANCES WILL INCREASE THE POTENTIAL FOR
SHOWERS AND THUNDERSTORMS...MAINLY OCCURRING OVER THE WATERS DURING
THE EARLY AND MID MORNING HOURS...THAN PERHAPS AGAIN DURING THE
AFTERNOON IF THE INLAND STORMS ARE ABLE TO PUSH ACROSS THE
SEABREEZE BOUNDARY INTACT. SEAS COULD BUILD TO 4-5 FT...HIGHEST
SUNDAY AFTERNOON AND EVENING...IN A COMBINATION OF LOCAL SHORT-
PERIOD WIND WAVES AND A CONTINUING SOUTHEAST SWELL WITH 8-9
SECONDS PERIOD.

LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 PM SATURDAY...REFLECTING THE SYNOPTIC PATTERN OF THE PUBLIC 
FORECAST...LITTLE CHANGE IF ANY FOR THE EXTENDED COASTAL WATERS
FORECAST. BERMUDA HIGH PRESSURE WILL BE THE PRIMARY FOCUS. ANY
WEAK SHORTWAVES EMBEDDED IN THE FLOW WHICH WOULD ENHANCE THE LOW
LEVEL JET AND SURFACE WINDS ARE ALL BUT IMPOSSIBLE TO TIME AND
PLACE THIS FAR OUT IN TIME. A PERSISTENT SOUTH TO SOUTHWEST WIND
OF 10-15 KNOTS SHOULD SUFFICE.

THE LATEST WAVEWATCH GUIDANCE HAS COME IN A BIT ON THE HIGH 
SIDE...ESPECIALLY FOR LATE WEDNESDAY INTO THURSDAY WHEN IT DEVELOPS 
SIX FOOTERS BASED PRIMARILY ON WIND WAVES. THE REEFCAST 
ENSEMBLES...WHICH DISPLAY REMARKABLE AGREEMENT THROUGH 
MIDWEEK...LOOK MORE REASONABLE WITH A FOUR TO FIVE FOOT RANGE.

IT APPEARS ANY SWELL FROM BERTHA HAS BEEN DELAYED FURTHER AT LEAST 
FROM THE GFS/WAVEWATCH. HOWEVER...MANUAL GRAPHICS FROM HPC ARE MORE 
PROGRESSIVE WITH THE SYSTEM. ANOTHER COMPLICATION IS THE EVENTUAL 
STRENGTH OF THE SYSTEM AND JUST HOW MUCH SWELL WILL BE EMANATING 
ACROSS THE WESTERN ATLANTIC. WILL HOLD OFF MAKING ADJUSTMENTS FOR 
NOW...BUT SUBSEQUENT FORECASTS WILL HAVE TO MONITOR WAVE FORECAST 
CLOSELY FOR THE END OF THE WEEK.

&&

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

&&

$$

NEAR TERM...RAS
AVIATION...DL