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fxus62 kilm 181757 
afdilm 


Area forecast discussion 
National Weather Service Wilmington NC 
157 PM EDT Friday Jul 18 2008 


Synopsis... 
a low pressure system developing off the Georgia coast will lift 
slowly north-northeast through the weekend...before finally 
exiting to the northeast of the area Monday. A trough of low 
pressure will linger over the Carolinas...with weak high pressure 
offshore...for most of the upcoming week. 


&& 


Near term /through this afternoon/... 
as of 10 am Friday...showers will continue to move across coastal 
counties today as weak onshore flow helps spread moisture and 
ongoing storms over the area. Large amounts of dry air to the 
north and west will prevent activity from making much inland 
progress. Morning update was mainly to address the pop issue. 
Raised probability of precipitation along the immediate coast into the likely realm and 
cut back on probability of precipitation inland. There may be a few isolated thunderstorms within 
the showers...but convective parameters suggest very limited 
coverage. While prolonged heavy rain and flooding may be an issue 
over the weekend precipitable waters  today remain below 2 inches. Brief period 
of heavy rain are likely...but durations will generally be less 
than 15 to 30 min. 


&& 


Short term /Saturday through Sunday/... 
as of 3 am Friday...GFS and NAM coming into better agreement with 
low pressure moving up the coast...however confidence is still not 
that high. At first glance models appear underdone with the 
moisture...however this system continues to fight dry air just 
inland over the Carolinas. In light of that dry air will split the 
difference in probability of precipitation...going from low chance inland to high chance 
on the coast for Sat...and tapering down in time. In reality I 
would think that the cutoff in precipitation will be much sharper but 
still cannot be sure that will be over land. 


Low center will lift north of the area by Sunday...pretty well 
eliminating any probability of precipitation inland and turning our attention to heat. 
Both Eta model/GFS MOS showing temperatures flirting with the upper 90s 
inland...but given the warm bias in situations like 
this...especially from the GFS MOS...would not expect to get any 
warmer than 95. 


&& 


Long term /Sunday night through Friday/... 
as of 3 am Friday...downslope flow behind the exiting low pressure 
center will make for largely hot and dusty conditions Monday and 
Tuesday. Will see deep mixing both days...which is just the 
scenario where GFS MOS has been way too warm...so will undercut 
highs by at least a category inland...which is still good enough 
for middle 90s. 


By Wednesday-Thursday the flow aloft takes on more of a west-southwest direction...and 
the Piedmont trough will be the main player at the surface. Will trend 
back toward climatology temperatures and probability of precipitation for days 6-7. 


&& 


Aviation /18z Friday through Wednesday/... 
convection propagating a bit further inland than previously thought 
so flow and lbt could see some brief convection. Models trending 
toward a wetter scenario overnight as surface low tracks a bit more 
west than previous model runs. Best chance for rain will be after 
midnight...as a slug of moisture rotates onshore around the low. 
Look for MVFR ceilings...with brief IFR visibilities in showers. 
Showers will continue into Saturday...as the low tracks slowly 
northeast. Ceilings could stay below VFR most of the day. 


Outlook through Tuesday...scattered showers and thunderstorms 
expected through Saturday night across all terminals. Much improved 
conditions Sunday into Tuesday. 


&& 


Marine... 
near term /through this afternoon/... 
as of 10 am Friday...onshore flow will continue today with a 
slight shift to more S-southeast later in the day. Gradient remain 
relatively unchanged today with speeds in the 10 to 15 knots range 
with seas 2 to 4 feet. 


Short term /Saturday through Sunday/... 
as of 3 am Friday...the main player will be low pressure moving 
slowly up the Carolina coast. For now will follow the NAM 
solution...which keeps the low just offshore and close enough to 
our waters to limit wind speeds. Low-confidence forecast so will 
not go for anything stronger than 15-20 knots...and also capping seas 
at 5 feet. Could see Small Craft Advisory conditions if the track is just slightly 
different...but will let later shifts refine that as directions 
could be seriously impacted. Once the low is north of the waters 
on Sunday...offshore flow will develop and knock the seas down 
quickly. 


Long term /Sunday night through Tuesday /... 
as of 3 am Friday...will start the period with light offshore flow 
and 2-3 feet seas. Expect a backing to SW later on Monday and 
especially into Tuesday as the Piedmont trough becomes more 
pronounced. Also look for wind speeds picking back up to around 15 
knots with the aid of the daily seabreeze...with seas remaining in 
the 2-4 feet range. 


&& 


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


&& 


$$ 


Near term...iii 
short term...Ras 
long term...Ras 
aviation...43