773 
fxus62 kilm 191406 
afdilm 


Area forecast discussion 
National Weather Service Wilmington NC 
1006 am EDT Friday Mar 19 2010 


Synopsis... 
low pressure east of Cape Fear will move out to sea today and 
tonight as high pressure builds into the area from the Gulf Coast 
states. This will bring warm daytime temperatures to the area. Low 
pressure over Arkansas Sunday will move through the central 
Appalachians early Monday...dragging a cold front through the 
Carolinas. Cool temperatures Monday and Tuesday will moderate later 
in the week. 


&& 


Near term /through tonight/... 
as of 10:00 am Friday...last of the middle and high level cloud cover 
is moving off to the east/northeast. Have tweaked down cloud cover 
grids a bit for the next few hours. This leaves maximum temperatures as 
the only forecast issue and the latest 0600 UTC guidance is fairly 
close to the current forecast. Numbers are a little higher inland 
although the 1200 UTC gso sounding is a little cooler than the 
models. Will monitor through midday to see if a degree or two needs 
to be added inland. No other changes. 


&& 


Short term /Saturday through Sunday night/... 
as of 4 am Friday...progressive flow and weather features affect the 
area through the short term. Models in decent agreement with broad area 
of high pressure off the southeast U.S. Coast affecting the area through 
Saturday night. Upper ridge axis moves off the coast of the 
Carolinas by midday Saturday with the approach of an upper short wave trough 
that closes off Saturday night along the Gulf Coast states. The 
closed low slowly but does move...east northeast to the southern 
Appalachians late Sunday night. Its accompanied more or less 
captured low stays with it. An upper vorticity is prognosticated to round the 
base of the upper low late Sunday and neward just ahead of the 
closed low Sunday night. This will provide the push for the cold 
front to reach the ilm County Warning Area after midnight Monday...and to the coast 
during the early daylight hours of Monday. The forcing/dynamics 
provided by this impulse will interact with the surface cold 
front...possibly resulting in severe weather along it. With no 
insolation involved to aid in any increased instability...will only 
mention possible isolated in the severe weather potential statement. Temperatures both days will average 5 
to 10 days above climatology norms. 


&& 


Long term /Sunday through Thursday/... 
as of 4 am Friday...ongoing cold frontal passage will start the long 
term early Monday with an isolated severe thunderstorm possible prior 
to its passage. Plenty of forcing aloft and from frontal dynamics 
will aid the possible severe weather. A later timing of the cold front passage during the 
day Monday would involve the days insolation and added instability 
resulting in an increased threat of severe weather. 


For the time frame after the cold frontal passage early Monday 
through Tuesday...the upper low will move east-northeast...passing just northwest-north of 
the ilm County Warning Area and off the Virginia convective available potential energy late Tuesday. The European is much 
farther south in its traversing of the upper low and would result in 
possible low probability of precipitation Tuesday. At this point prefer the slightly 
northern GFS Route. However...have included additional cloudiness 
during this period as a result of the cold pool instability and 
enough available moisture. A secondary surface cold front or trough 
passage is slated Tuesday afternoon as the upper/surface lows off the Virginia 
convective available potential energy begins pulling away. 


For Wednesday into Thursday...a short wave upper ridge will become the 
dominant weather feature aloft affecting the ilm County Warning Area with relatively weak 
and broad high pressure underneath it. 


As for temperatures...Monday and Tuesday will see temperatures below climatology 
norms...especially Tuesday due to the upper low cold pool affects. 
Middle March insolation expected to warm things up dramatically 
Wednesday and Thursday...to above climatology norms. 


&& 


Aviation /12z Friday through Tuesday/... 
as of 12z...surface low pressure off the coast is moving east 
northeast further away from the coast. Surface high pressure has 
moved into the southeast US with upper level ridge in support. This 
scenario will bring high confidence for VFR skies and visibility for the 
period. Only residual middle level cloudiness mainly along the coastal 
sites to start the period. Infrared satellite shows middle and high clouds 
circulating around the upper short wave and moving off the coast to 
the east. 


Wind will be northwesterly 5 to 12 knots for most of the period. 
After 00z wind to become light and variable as high pressure 
dominates the eastern Seaboard. 


Extended outlook...high confidence for VFR through Sunday day. 
Moderate confidence tempo IFR visibilities/isolated thunderstorms 
Sunday evening through midday Monday. VFR Tuesday. 


&& 


Marine... 
near term /through tonight/... 
as of 10:00 am Friday...have trimmed back seas slightly to match 
current buoy observations...otherwise no changes. Still expect northwest 
flow of 10-15 knots and seas of 2-4 feet. 


Short term /Saturday through Sunday night/... 
as of 4 am Friday...broad area of high pressure off the southeast U.S. 
Coast will extend across the waters Saturday into Saturday night. 
Expect light southeast or S winds through this period...except near shore 
where an active sea breeze Saturday afternoon/evening will result 
in higher southerly winds near shore. For Sunday...retreating surface high 
and the approach of a cold front from the west will result in a 
tightening of the surface pg resulting in southeast-S winds slowly increasing 
during Sunday...likely reaching scec or Small Craft Advisory thresholds by and 
continuing into Sunday night. Decent southeast-S fetch by Sunday evening 
and night will result in seas building to Small Craft Advisory levels. Scattered 
thunderstorms will increase in coverage Sunday night ahead of the 
cold front which could spawn wind gusts up to smw criteria between 
midnight and daybreak Monday. 


Long term /Monday through Monday/... 
as of 4 am Friday...cold frontal passage slated early Monday morning 
with winds becoming SW scec or low threshold Small Craft Advisory force. Seas will 
have been built up to Small Craft Advisory levels due to scec/Small Craft Advisory southeast-S winds prior to 
the cold front passage. The main surface low to traverse east-west across the midatlantic 
sates during Monday...then off the Virginia coast and offshore during 
Tuesday. This in response to the closed low that captures the surface 
low which also slowly moves off the Virginia convective available potential energy Tuesday. Expect a 
secondary cold frontal passage during Tuesday...with winds becoming 
west-northwest through north-northwest at scec levels. Seas will be in a diminishing trend 
except the waters from Cape Fear to Little River Inlet where SW-west 
winds leading up to the secondary cold front passage could keep seas in scec or Small Craft Advisory 
levels. 


&& 


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


&& 


$$ 
Near term...shk 
short term...dch 
long term...dch 
aviation...mdc 

National Weather Service Glossary of Abbreviations

Non-Expanded Version (with abbreviations)