271 
fxus62 kilm 211449 
afdilm 


Area forecast discussion 
National Weather Service Wilmington NC 
949 am EST Friday Nov 21 2008 


Synopsis... 
a strong upper level disturbance will bring the chance for 
flurries today...mainly over southeastern North Carolina. Arctic 
high pressure will build in over the weekend. A slight moderation 
on Monday will precede another strong cold front Monday night. 
High pressure will build in for the rest of next week...keeping 
temperatures below normal but not as cold as the past several days. 


&& 


Near term /through tonight/... 
as of 9 am Friday...surface low pressure taking shape well off the NC 
coast as a vigorous upper disturbance passes just north of the 
area. If there is a time for flurries it is just the next couple 
of hours as visible Sat imagery shows clearing along and west of I-95. 
Strong cold air advection will limit any recovery in temperatures...and current maximum temperature 
forecast in the middle/upper 40s looks a-OK. 


Not quite ideal radiational cooling conditions tonight as the high 
remains just far enough west to keep north-northwest winds around 5 knots through 
the night. Still the airmass is cold enough to threaten record low 
temperatures. See short term section to compare standing records. 


&& 


Short term /Saturday through Sunday night/... 
as of 3am Friday... 
Arctic high firmly entrenched across most of the southeast will bring 
a Cold Saturday with highs only in the middle 40s. Some uncertainty as 
to how Cold Saturday night gets. A clipper-ish shortwave may bring 
just enough cloud cover to disrupt an otherwise ideal radiational 
cooling setup. Given the dry nature of the Arctic air have 
forecasted fewer clouds than guidance would suggest and have kept 
with cooler Eta model MOS/continuity...middle 20s everywhere. Modification 
of the airmass by the weak late November sun will bring highs in 
the middle 50s...still 10 degree below climatology. 


Record lows for: November 22nd November 23rd 


Ilm: 24 degree set in 1937 23 degree set in 1981 
cre: 24 degree set in 1951 24 degree set in 1949 
flo: 20 degree set in 2000 24 degree set in 1976 


&& 


Long term /Monday through Thursday/... 
as of 3am Friday...highs in the middle 60s on Monday will be the 
closest to climatology we have seen in a while as high pressure moves 
offshore. This allows for the advection of warmer air as well as 
moisture. Late day low level jet starting to look impressive on 
forecasts and would not be surprised to see probability of precipitation raised in future 
forecast iterations. Rest of the long term will be dry and cold as 
large storm system cuts off and remains quasi stationary in the 
northeast. 


&& 


Aviation /15z Friday through Tuesday/... 
a cold front moved through the terminals earlier this morning. 
Higher winds just off the surface (north near 25 knots at 600 feet agl) 
or near the frontal inversion is producing low level wind shear 
conditions at Flo/lbt. Low level wind shear conditions should end by 14z at these 
terminals as northerly winds increase due to vertical mixing with 
gusts to 20 knots. Increasingly cold middle-level temperatures by 15z 
today will steepen lapse rates sufficiently to produce 3000 to 5000 
feet deep cumulus clouds and increase wind gusts to 25-30 knots. A few 
snow flurries are possible near the lbt and ilm airports later this 
morning...but no significant visibility restrictions are expected. 
Skies should scatter out by early afternoon at flow/lbt and middle to 
late afternoon at the coastal terminals. Gusty north to northwest 
surface winds will decrease by 23z. Low level wind shear will 
possible at that time. VFR this evening and overnight with clear 
skies. 


Outlook through Tuesday...VFR. 


&& 


Marine... 
near term /through tonight/... 
as of 9 am Friday...cold surge getting better established over the 
waters with north-northeast winds just touching Small Craft Advisory thresholds. Tight gradient 
will persist and cold air advection will provide deeper mixing...so NC waters 
could touch 30 knots later this afternoon and tonight. However with 
the winds backing northwest by this afternoon...fetch will be severely 
limited so seas have been capped at 7 feet. 


Short term/Saturday through Sunday night/... 
as of 3am Friday...tail end of the cold surge Marks the start of the 
period and possibly the end time of Small Craft Advisory conditions. 
Arctic high will build in rather quickly though making for 
improving...albeit very cold conditions on the water as winds and 
seas subside. Winds continue to lighten as the high builds in on 
Sunday and there may be a little uncertainty regarding the exact 
wind direction. 




Long term/Monday through Tuesday/... 
as of 3am Friday...late day passage of a cold front accompanied by 
strong dynamics aloft Monday. Guidance looks a little underdone on 
winds even given cooler SSTs. Small Craft Advisory may be needed 
Monday night/Tuesday. 


&& 


Ilm watches/warnings/advisories... 
SC...none. 
NC...none. 
Marine...Small Craft Advisory until 7 am EST Saturday for amz250-252- 
254-256. 


&& 


$$ 


Near term...Ras 
aviation...mrr