427 
fxus62 kilm 040521 
afdilm 


Area forecast discussion 
National Weather Service Wilmington NC 
120 am EDT Friday Jul 4 2008 


Synopsis... 
Bermuda high pressure will dominate the weather through the period. 
This will bring a return of thunderstorm chances by this weekend. 
Seasonable temperatures...high humidity...and thunderstorm chances 
will persist into the middle of next week. 


&& 


Near term /through tonight/... 
as of 9 PM Thursday...isolated convection along the seabreeze in 
South Carolina lasted until about 7 PM...then died as surface-based 
instability waned. Our radar estimates that over an inch of rain may 
have fallen along the Horry-Marion County line just north of U.S. 
Highway 378 this afternoon. A rather strong convective cap around 
600 mb (15000 ft) should preclude any further convection overnight. 


Synoptically...high pressure well offshore is bringing a southerly 
flow across the Carolinas. A cold front in the Ohio Valley separates 
the East Coast from a cooler airmass to the north anchored by high 
pressure over southern Minnesota. With winds dying away overnight 
and partly cloudy skies expected...lows should reach the upper 60s 
to around 70...a degree or two below normal for the date. Cirrus 
streaming north along the coast is associated with a 200 mb trough 
which should push offshore overnight with no sensible weather down 
here at the surface. 


&& 


Short term /Friday through Saturday night/... 
as of 3 PM Thursday...weak upper trough will be positioned west of the 
forecast area through the short term period. At the surface... high 
pressure will persist off the southeast coast while a weak trough 
exists inland with a nearly stationary front farther upstream across 
the Ohio to middle MS valleys. Instability will increase by Saturday 
and could be better support aloft especially across the central and 
western Carolinas west/ an 300 mb jet positioned across WV and eastern Kentucky. 
Thus better chances for rainfall as we head into the weekend vs 
Friday. Continue to favor a blend of mav/met numbers through the 
period...which is right around climatology. 


&& 


Long term /Sunday through Wednesday/... 
as of 3 PM Thursday...Bermuda high remains the dominant weather feature 
through the extended so counting on mainly a persistent type 
forecast. Middle level troughiness on sun will be replaced by ridge 
building in across the southeast by Monday. Local area will remain on 
the western periphery of the ridge Monday through the rest of the 
extended. Therefore plenty of middle to upper level moisture will ride 
into area probably more in the way of cirrus coming up from any 
convection over the Gulf and southwest. This should create some 
partly sunny or hazy sunshine in the extended period. Overall not 
expecting much more than diurnal showers and thunderstorms under 
hazy hot and humid conditions typical of summertime. Pcp water up 
close to 2 inches from Sun afternoon onwards with moisture profiles 
showing bulk of moisture below h70 and above h40. Therefore 
expecting more in the way of cumulus building each afternoon and a good 
deal of cirrus. Showers and thunderstorms will be focused in diurnally 
favored spots especially along the sea breeze boundary. Probability of precipitation 
basically in chance category in the afternoon and slight chance overnight over 
land areas. 


Temperatures will have less of a diurnal variation through the extended 
with day time temperatures reaching right up near climatology and overnight temperatures 
a little above normal. 


&& 


Aviation /06z Friday through Tuesday/... 
only some minor tweaking to the previous 00z set of tafs with VFR 
conditions expected through the forecast period. Slight chance of 
some very light fog inland...with decent radiational cooling and 
dewpoints slowly creeping up. An altocu deck at 10k feet to push 
across the area before sunrise Friday. Southwest flow for to 
continue through Friday...with resultant/sea breeze to develop 
around noon and push inland. Initially...models indicate subsidence 
aloft to curtail any vertical development with the cumulus...but by 
afternoon and evening...some weak positive vorticity advection moves in from the west along 
with the Piedmont trough having become a bit more stronger. As a 
result...isolated thunderstorm activity along the Piedmont trough 
could drift to I-95...possibly affecting lbt and/or flow. There4 it 
seems prudent to include vicinity thunderstorms and rain at these 2 inland terminals 
for now...unless convective coverage increases. 


Outlook through Tuesday...isolated/scattered convection expected 
Saturday...with scattered storms Sunday through Tuesday. 


&& 


Marine... 
near term /through tonight/... 
as of 9 PM Thursday...return flow around Bermuda high pressure will 
keep southerly winds around 10 knots overnight...perhaps veering to 
southwest or west near the coastline late with a landbreeze 
developing. Wave energy overnight should not amount to much...but 
consists of two different southeast swells totaling about 2 feet in 
amplitude. The larger of the two has an 8 second period...and the 
smaller has an 11-12 second period. The longer period swell is shown 
by the latest wavewatch guidance to dissipate during the day Friday. 


Short term /Friday through Saturday night/... 
as of 3 PM Thursday...S to SW flow will be the rule during the short term 
period with high pressure established off the southeast United 
States coast. Will see daily increase in wind speed with the sea 
breeze continuing into the early evening...diminishing overnight 
each night. Wavewatch heights look reasonable with 3 feet seas...up to 
4 feet at times coincident with the wind speed increase each afternoon 
and early evening. 


Long term /Saturday through Monday/... 
as of 3 PM Thursday...not expecting much through the extended as Bermuda 
high dominates the local weather. Winds should remain in the 10 to 
15 knots range with diurnal effects being the main player...expecting 
increase in S winds each afternoon as sea breeze kicks in producing 
some choppiness mainly near shore. Seas should remain in the 2 to 4 
feet range overall. May have to contend with some longer period swells 
from Bertha spinning out over the distant Atlantic heading into middle 
week next week. 


&& 


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


&& 


$$ 


Near term...tra 
short term...srp 
long term...rgz 
aviation...hoehler/loewenthal