Weather

289 
fxus62 kilm 281927 
afdilm 


Area forecast discussion 
National Weather Service Wilmington NC 
327 PM EDT Thursday Aug 28 2008 


Synopsis... 
a weak trough of low pressure will linger over the eastern 
Carolinas through Friday. A cold front will push southeast across 
the region Sunday. High pressure will build in from the 
north Monday through the middle part of next week. 


&& 


Near term /until 6 am Friday morning/... 
as of 3 PM Thursday...showers and thunderstorms are ongoing mainly 
from North Myrtle Beach and northeastwards...over 
Brunswick...eastern Columbus...New Hanover and Pender counties. 
Activity was kicked off by a short wave now moving offshore in 
conjunction with peak daytime heating. Water vapor imagery shows 
significant drying to the west of this area so expect remainder of 
the County Warning Area to remain dry. Activity will fade as dryer air moves in and 
we lose daytime heating. Overnight will be mostly dry with just 
slight chance for showers...again for the aforementioned 
counties...as another weaker short wave moves through. Forecast 
challenge for overnight will be extent of fog formation. Plenty of 
ground level moisture and light winds makes fog a good bet for 
tonight. Guidance hits inland areas hardest with fog. See no reason 
to dispute this so have followed guidance in this area. Stayed on 
the high side of for overnight temperatures as guidance has been under doing 
it lately. This will keep min temperatures in the low to middle 70s 
overnight...about a category above climatology and a tad lower than last 
night. 




&& 


Short term /6 am Friday morning through Saturday night/... 
as of 3 PM Thursday...diffuse pattern both aloft and at the surface 
will prevail through the period. At 500mb...the eastern Carolinas 
are in between ridges to the east and west while the main belt of 
westerlies remains well to the north. At the surface...a weak 
coastal trough will remain across the area. 


Chances of showers and thunderstorms will be primarily driven by 
afternoon heating and the sea breeze and the coastal trough that 
will meander to the Piedmont during the late afternoon hours. 
Precipitable waters...which have dropped a bit today...will recover 
nicely to in excess of two inches by Friday afternoon. Used low 
chance values for all areas both Friday and Saturday for the 
afternoon tapering down quickly in the evening and overnight hours. 


Temperature guidance had reverted back to the usual trends with the 
GFS/mav numbers about a category above the met and FWC numbers. Will 
continue to make the safe play and use the cooler numbers. The 
oppressive humidity looks to continue as well with dewpoints in the 
lower 70s throughout at the coast with slightly lower values inland. 


&& 


Long term /Sunday through Thursday/... 
as of 3 PM Thursday...with respect to the upper atmosphere...a 
transformation will be taking place. The residual upper trough will be 
finally lifting and progressing east northeastward sun through Monday. In 
its place...a rather large amplitude upper ridge will develop and 
affect the area and much of the eastern Seaboard by Tuesday...and 
will last into Thursday. At the surface...a cold front will initially 
move through the area on Sunday into early Monday. This will be the 
only time frame when probability of precipitation/precipitation will be illustrated across the ilm 
County Warning Area. Otherwise with the upper ridge developing...the surface high 
centered over the NE states...will ridge across the eastern sea 
board including the ilm County Warning Area Monday through Thursday. At this point 
in time...this should keep Gustav steered into the Gulf. Hanna on 
the other hand will be a question mark of which eventual direction 
it takes as is advertised in the NHC forecast. Mainly a temperature 
forecast after the frontal passage early Monday...with a nearly 
persistence daily temperature forecast on tap. Overall...Max/min temperatures 
across the ilm County Warning Area will right around the climatology norms. 


&& 


Aviation /19z Thursday through Tuesday/... 
showers and thunderstorms are ongoing mainly from North Myrtle 
Beach and northeastwards...over Brunswick...New Hanover and Pender 
counties...as a short wave moves offshore. Water vapor imagery 
shows significant drying to the west of this area so expect lbt 
and flow and possibly myr to remain out of strong convection while 
cre and especially ilm will have a good chance for it. Activity 
will fade as dryer air moves in and we lose daytime heating. 
Forecast challenge for overnight will be extent of fog formation. 
Plenty of ground level moisture and light winds makes fog a good 
bet for tonight. Guidance hits inland areas hardest with LIFR. See 
no reason to dispute this so have followed guidance in this area. 


Outlook through Tuesday...chances for thunderstorms Saturday and 
Sunday. 


&& 


Marine... 
near term /through tonight/... 
as of 3 PM Thursday...slack gradient will keep winds 
light...generally 10 kts or less overnight. As a result seas will 
not vary much from present values...ranging from a foot and a half 
near shore to 3 feet out at 41013. 




Short term /Friday through Saturday night/... 
as of 3 PM Thursday...with the weak pressure pattern in place...and 
the absence of any significant swell...mariners will enjoy a rather 
tranquil weekend with winds 10-15 knots at most...probably closer to 
10 and seas of 2-3 feet. 




Long term /Sunday through Tuesday/ 
as of 3 PM Thursday...beginning of the long term will be highlighted 
by the passage of a cold front by late Sunday or early Monday. 
After-wards...an upper ridge becomes the dominant weather feature 
through Tuesday. Surface high pressure centered across the NE states to 
ridge across the area waters Monday through Tuesday. This will provide 
a decent NE wind of at least 15 knots...which may be too conservative... 
through Tuesday. Short period wind driven waves will respond and 
increase in size...and likely become the dominant and overall seas. 
An underlying 2 foot southeast ground swell will continue to exist throughout 
the long term. 


&& 


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


&& 


$$ 
Synopsis...shk 
near term...rek 
short term...shk 
long term...dch 
aviation...rek 

National Weather Service Glossary of Abbreviations

Non-Expanded Version (with abbreviations)