623 
fxus62 kilm 061337 
afdilm 


Area forecast discussion 
National Weather Service Wilmington NC 
937 am EDT sun Jul 6 2008 


Synopsis... 
seasonably warm and humid conditions will persist through the 
next several 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. A cold front will approach 
the local area Thursday with high pressure to follow as we head 
into next weekend. 


&& 


Near term /through tonight/... 
as of 9 am Sunday...upper low over the Ohio Valley becoming 
elongated but cut off...with deep SW flow ahead of it over the 
Carolinas. Surface pressure pattern is a bit baggy due to cluster of 
storms offshore lifting past the ilm County Warning Area. 


It is difficult to discern the impulses rounding the base of the 
upper trough...but given a moist...unstable...and boundary-rich 
environment it will not take much to initiate convection. Piedmont 
trough and resultant seabreeze boundary will likely be the main 
players...but enough other boundaries around today that I will not 
hang my hat on that. 


Main issue looks to be heavy rain...as better availability of deep 
moisture will offset slightly faster storm motion than in previous 
days. Severe threat will be isolated at best given the moist 
adiabatic middle-level lapse rates and a shallower low-level mixed 
layer. 


The bottom line is only minimal changes to the going forecast. 


&& 


Short term /Monday through Tuesday night/... 
as of 3 am Sunday...middle level trough lifts off to the northeast by 
Monday night with flow becoming flatter as we move into Tuesday. 
Therefore have kept probability of precipitation up in the likely category on Monday...but 
will drop off Tuesday as upper level support diminishes and some drier 
air moves in. Pcp water values decrease to around 1.5 inches 
through Tuesday night so not expecting much in the way of showers 
and thunderstorms for Tuesday afternoon. 


Temperatures should be be near or slightly above the warmest guidance for 
lows...and near guidance consensus for highs through the period 
given the moist airmass. 


&& 


Long term /Wednesday through Saturday/... 
as of 3 am Sunday...Bermuda high in place to start the long term. 
Starts out a little drier Wednesday morning...but moisture quickly 
rebounds as pcp water values increase again to over 2 inches with 
deep layer moisture present by Thursday. GFS showing a front moving 
into local area on Thursday and possibly stalling over local area 
through on Friday with drier surface high pressure ridging down from the 
northeast for the weekend. For now will go with diurnal showers and 
thunderstorms Wednesday with more widespread activity Thursday and Friday with 
plenty of lift and moisture present as front moves into area. Have 
lower probability of precipitation over next weekend but kept diurnal low end chance probability of precipitation for 
that part of the forecast as high pressure tries to ridge into local 
area...but lingering moisture from front seems to remain. GFS does 
have a considerable amount of dry air over local area by the latter 
half of next weekend. 


The GFS shows the latest track of Bertha near Bermuda by next 
Monday...and European model (ecmwf) curves the storm even farther east way off in the 
distant Atlantic. Its just too early to know exactly how this one 
will pan out. 


&& 


Aviation /14z Sunday through Thursday/... 
the main forecast concern today will be timing of convection. 
Look for convection to fire first along the resultant around 
midday with more widespread 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 maximum heating each day. MVFR to IFR conditions 
possible in thunderstorms Sunday evening through Tuesday. Fog is 
possible prior to sunrise each morning...especially in areas that 
see rain. 


&& 


Marine... 
near term /through tonight/... 
as of 9 am Sunday...overnight convection has passed east of the 
waters with little fanfare...and buoy observation show 10-12 knots winds out 
of the west-southwest and seas around 3 feet. Expect the afternoon seabreeze to 
bump wind speeds up to a solid 15 knots. Based on current observation and a 
couple days Worth of trends...will keep seas in the 3-4 feet 
range...about a foot off of ww3 guidance. 


Short term /Monday through Tuesday night/... 
as of 3 am Sunday...Bermuda high will continue to provide a 
southerly flow across the local waters. A middle to upper level trough 
will increase the chances for showers and thunderstorms still on 
Monday...but will lift off by Tuesday with quieter weather expected. 
Persistent winds out of the south will maintain seas in the 3 to 4 
feet range and possibly up to 5 feet well off shore. South winds will be 
in the 10-15 knots range through most of the period. 


Long term /Wednesday through Thursday/... 
as of 3 am Sunday...south to southwest flow of 10-15 knots will 
continue around the Bermuda high with a slight daytime increase of 
wind speeds closer to the coast due to the influence of the sea 
breeze. Seas should remain in the 2 to 4 feet range. 


Some longer period easterly swells from Bertha could affect the 
coastal waters by Thursday. Any longer period swells from Bertha will 
depend on the strength and track of Bertha over the next several 
days. Therefore will have to continue to monitor the forecast 
closely through the end of the week. 


&& 


Ilm watches/warnings/advisories... 
SC...none. 
NC...none. 
Marine...none. 


&& 


$$ 


Near term...Ras 
aviation...heden