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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Wednesday
• 
• High: 82 °
• Low: 70 °
• T-Storms

• Thursday
• 
• High: 81 °
• Low: 66 °
• T-Storms

• Friday
• 
• High: 82 °
• Low: 70 °
• T-Storms

• Saturday
• 
• High: 82 °
• Low: 68 °
• Fog

• Sunday
• 
• High: 82 °
• Low: 72 °
• Fog

Area forecast discussion 
National Weather Service Wilmington NC 
1033 am EDT Wednesday may 23 2012 


Synopsis... 
an upper level disturbance will bring showers and thunderstorms to 
the area through Thursday. Some thunderstorms today may be severe. 
A drying trend will follow Friday through early next week as an 
upper ridge intensifies over the Carolinas. 


&& 


Near term /through tonight/... 
as of 1033 am Wednesday...vapor animations show the center of the 
impulse aloft and cold pool is centered near the NC/SC eastern 
border. This should equate to 500 mb temperature around -15 to -16 
degree c presently. Visible pictures show full may sunshine warming the 
ground and there is little doubt destabilization will intensify as 
we approach peak heating. Slightly drier air is wrapping across the 
southern periphery of the cold pool aloft...but how much this will 
serve as an inhibitor is unclear. It could in fact enhance hailstone 
generation and stronger evaporative cooling downbursts if convection 
punctures through the weakening cap. 


Widespread sunshine across the area should prompt a sea breeze which 
in turn will serve as a convective initiation boundary. Downdraft 
convective available potential energy are running very high suggesting a strong downburst potential 
coincident with potentially large hail. Diurnal cooling and drying 
from S to north will curtail convection in the evening. 


&& 


Short term /Thursday through Friday night/... 
as of 3 am Wednesday...middle to upper trough will lift off to the 
northeast as ridge builds in from the west Thursday through Friday. 
Southerly return flow around Bermuda high will shift around to the 
northeast as high pressure builds down from the north Friday into early 
Sat. As trough lifts off drier air will wrap around from the SW and 
increased subsidence will help to keep showers to a minimum...but with 
dewpoints in the middle 60s kept some isolated convection along sea 
breeze boundary in the afternoon both Thursday and Friday. 


A wave of low pressure moving westward toward the southeast coast 
should be suppressed toward the south as ridge of high pressure 
builds over the area from the surface up through the middle to upper 
levels heading into the weekend. The NAM/European model (ecmwf) and CMC bring this 
wave toward the Carolina coast as early as Friday before ridge gets a 
chance to build in. The NAM brings it close enough to produce an 
increased easterly fetch with showers affecting the local coastal 
waters and possibly coastal land areas by late Friday before moving 
south. This system does get held back to the east and suppressed 
southward by ridge building in by Sat. The GFS keeps this wave much 
farther south closer to the Bahamas. For now will discount the more 
aggressive NAM and will keep any showers mainly off shore Friday into 
Friday night. 


As for temperatures...a humid more Summer like air mass will be in place 
with dewpoint temperatures running in the 60s. 500 mb heights will be slow to 
rise as ridge builds slowly into area with 850 temperatures rising from 
15c Thursday up close to 16c by Friday afternoon. Therefore expect temperatures 
about the same both days in the middle to upper 80s with slightly 
lower values right along the coast and middle 60s overnight. 


&& 


Long term /Saturday through Tuesday/... 
as of 3 am Wednesday...a Summer-like warm and humid air mass will 
be in place. Ridge will be building in aloft over the weekend 
cresting overhead on Sunday with plenty of subsidence and dry air 
aloft. 500 mb heights rise up to 590 dem by Sun afternoon. Moisture will be 
limited mainly below 5k feet. A wave of low pressure heading toward 
the southeast coast from the Atlantic waters will get suppressed 
south as high pressure builds down from Canada and ridge builds 
aloft. Therefore expect very warm weather with minimal shower 
activity through the extended period. Winds will be northeast 
initially as high builds from the north but as it shifts off the 
Hatteras coast through Sunday the winds will veer around to the 
east. By Monday the center of the high will shift just to our east 
with a southerly return flow setting up. The ridge will move east 
as middle to upper trough pushes a cold front into the Carolinas from 
the northwest Tuesday night into Wednesday but any increase in shower 
activity should hold off until late Wednesday. Will add isolated pcp 
back in forecast by Monday with increasing return flow setting up. 


850 temperatures rise from around 16c Sat up to 18c through Monday. 
Overall expect very warm temperatures through the extended with readings 
in the middle 80s to around 90 inland. Overnight temperatures will remain 
in the 60s in a more humid air mass. 


&& 


Aviation /14z Wednesday through Sunday/... 
as of 14z...tempo MVFR visibilities are occurring at the lbt/flow 
terminals with VFR at the coastal terminals. Precipitation is 
currently offshore. 


Expect a good chance of periods of MVFR ceilings through 18z. 
There is high confidence at least isolated to scattered showers 
and thunderstorms will develop today. With low convective 
temperatures convection could begin earlier than normal. With a 
weak pressure gradient and numerous boundaries from recent storms 
there is low confidence as to exactly where the storms will 
develop. Highest confidence will be along the northern portion of 
the sea breeze boundary near ilm....and in the best moisture axis 
from near lbt to ilm. Thus...there is moderate confidence tempo 
thunderstorms/MVFR flight conditions will occur at the ilm/lbt 
terminals...but confidence in timing is low. Lowest confidence of 
thunderstorm occurrence will be at the flow/myr terminals. IFR 
flight conditions could occur with some of the thunderstorms...but 
expect any IFR to be too brief to significantly affect flight 
operations. 


Precipitation ends this evening as skies gradually become scattered. 
With moist soils expect br to develop. Since any dense fog is 
expected to be patchy confidence is moderate overall that 
visibilities will be in the MVFR range. 


Extended outlook...scattered showers/MVFR...with isolated 
thunderstorms/tempo IFR possible through the extended period. 


&& 


Marine... 
near term /through tonight/... 
as of 1033 am Wednesday...swell churned up by former Tropical Storm 
Alberto will slowly wane. Winds today will remain from the south-southwest at 10 
to 15 knots. Winds will be higher in the vicinity of thunderstorms. The 
wind direction will tend to back and diminish tonight. Seas will 
range from 3 to 5 feet this morning...but the trend will be downward 
this afternoon and tonight. Mariners should expect higher seas in 
the vicinity of thunderstorms...and a check on radar trends may 
prove useful this afternoon and tonight. Sea spectrum will be a mix 
of southeast waves 2-3 feet at 9 seconds and south-southwest waves 1-2 feet in 5-6 
second wave intervals. 


Short term /Thursday through Friday night/... 
as of 3 am Wednesday...southerly return flow around Bermuda high 
will shift around to the northeast as high pressure builds down 
from Canada on Friday. A wave of low pressure approaching from the 
east may help to increase showers over the coastal waters mainly off 
shore on Friday but this low will get suppressed farther south as 
ridge builds in both at the surface and aloft. Winds should remain 10 
to 15 kts enhanced by the afternoon sea breeze near shore. This will 
produce seas 2 to 4 feet. 


Long term /Saturday through Sunday/... 
as of 3 am Wednesday...as high pressure builds down from Canada on 
Saturday expect northeast winds 10 to 15 kts. As this high shifts 
off shore just north of local waters...winds will shift around to 
the east and eventually southeast by Monday. A slightly tighter gradient 
may exist initially between wave of low pressure to the southeast 
in the Atlantic waters and high pressure building down. This will 
produce seas up around 4 feet in outer waters but as the gradient 
weakens as high moves closer overhead through Sunday...expect seas 
less than 4 feet throughout. 


&& 


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


&& 


$$ 


Near term...mjc 
short term...rgz 
long term...rgz 
aviation...mrr