Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington NC
1015 PM EST Monday Mar 2 2015
cool high pressure will build down from the north overnight into
Tuesday before a warm front lifts northward during Tuesday night.
Wednesday will feature a dramatic warm up only to be followed by
another even colder air mass Thursday and Friday. The weekend will
bring a very gradual warm up as well...along with an increase in
clouds and rain chances.
Near term /until 6 am Tuesday morning/...
as of 1015 PM Monday...a weak cold front had pushed well S of NE
SC this late evening...positioned from S of chs across central
Georgia with NE-east-northeast winds behind the front across the forecast
area. Temperatures will continue to fall but not quickly into
Tuesday morning...settling in the upper 30s across the deeper
interior of southeast NC to the low and middle 40s across most of SC and
coastal NC. The onshore component of east-northeast flow may keep our coastal
locations in the upper 40s into daybreak. Slight chance to chance
of rain into the pre-dawn hours of Tuesday. Radar was picking up
virga moving into central SC but measurable rainfall was still
well west into Georgia. No significant changes to the forecast
with this update...some minor adjustments to winds and T/TD/rh
Short term /6 am Tuesday morning through Tuesday night/...
as of 325 PM Monday...cool high pressure will prevail during Tuesday
however ample moisture in the lower and middle levels will overspread
the region. Rain chances increase during the day Tuesday as
isentropic lift increases. A warm front begins to lift northward
across the area Tuesday night. Thus mins will primarily occur in the
evening most locations then temperatures will rise into the early morning
hours Wednesday. Gusty south-southwesterly flow is expected
Wednesday. Any sea fog that develops along the cooler shelf waters
Tuesday night into early Wednesday should easily dissipate during
the morning as the wind increases. The southerly fetch overriding
the cooler shelf waters will also hold high temperatures down along
the coast...especially across coastal Brunswick and southern New
Hanover counties. Slight chances of showers will persist during
Wednesday with better chances to follow as the next cold front moves
into the picture during the long term period.
Long term /Wednesday through Monday/...
as of 325 PM Monday...models have been inconsistent when it comes to
the cold frontal passage. Looks like the latest GFS holds middle to
upper ridging over the southeast through early Thursday with low
pressure wave riding up along the surface front which is still back over
eastern Carolinas Thursday morning. Therefore it looks like Thursday
will now start out very warm in southerly flow until front makes its
way through by noon. There will be more of an abrupt change in winds
from SW to north once front drops south. The main shortwave energy will
remain well northwest of coastal Carolinas and looks like most of
pcp will come along and behind front through Thursday...more in the way
of convection along front and stratiform rain as warm SW winds aloft
ride over the shallow cool air behind surface front Thursday afternoon. Warmest
temperatures on Thursday will be early morning before frontal passage.
By Thursday night shortwave will move off the east leaving a broad
trough over the east with more of zonal flow in the middle to upper
levels and cold northwest to northerly flow as high pressure builds in at
the afc. This should help bring plenty of dry and cold air into the
area Thursday night through Friday. Pcp water values up near 1.5 inches
Thursday morning will drop to less than quarter of an inch Thursday night
through Friday. Expect dry high pressure through at least Friday.
By Saturday the high moves off shore over the middle Atlantic and
weakens. A broad trough remains over the east and there will be
potential for other shortwaves to move through the southeast and
possibly produce some waves of low pressure over the weekend.
Therefore will keep some low end probability of precipitation over the weekend. The GFS
shows greater chance of pcp on Sat while the European model (ecmwf) holds any pcp off
until Sun night into Monday.
Temperatures will take a dive once cold front drops south on Thursday with 850
temperatures up around 12c Thursday morning dropping down near 0c by Friday
morning. This strong cold air advection and possibly lingering clouds and pcp will
keep very cool temperatures for Thursday afternoon into Friday. After maximum temperatures
early Thursday temperatures will fall into the 40s late Thursday and will remain
about 20 degrees below normal for Friday. Overnight lows should drop
below freezing most places both Thursday night and Friday night as high
pressure shifts closer overhead. With middle to upper trough lingering
over the east through the weekend into early next week...expect
below normal temperatures through the weekend with temperatures near freezing
overnight. Although any sunshine will help bring them up a notch.
Aviation /03z Tuesday through Saturday/...
as of 03z...visible satellite shows a boundary moving southwest
down the coast. This could briefly give the coastal terminals an
MVFR ceiling for an hour or two. This boundary is associated with
high pressure building from the north overnight. Some overrunning
precipitation will begin on Tuesday...with increasing low level
moisture preceding it. Look for MVFR ceilings at all terminals
Tuesday with east northeast flow. Precipitation will become more
widespread as the day progresses...with possible IFR conditions
toward the end of the forecast period.
Extended outlook...becoming VFR Tuesday morning...with periods of
MVFR/showers Tuesday afternoon and evening. Showers late Wednesday. Rain/IFR Thursday.
VFR developing Friday and continuing into Saturday.
near term /through tonight/...
as of 1015 PM Monday...east-northeast winds 15-20 knots over the waters in wake
of a relatively weak cold front...and suspect gusts to 25 knots
remains quite possible so the Small Craft Advisory to be retained into daybreak
Tuesday. The winds should boost wave heights another 1-2 feet to
reach 3-5 feet most areas of the 0-20nm waters by sunrise Tuesday.
Short term /Tuesday through Wednesday night/...
as of 325 PM Monday...NE to east fetch Tuesday will veer to a southeast to
S wind by Tuesday night with the northward push of a warm front.
Winds will increase as the SW pressure gradient tightens during
Wednesday. Could see a period of patchy dense fog across the
cooler shelf waters Tuesday night...then the strengthening winds
will help to dissipate any sea fog by Wednesday morning. Seas
could possible increase to near small craft thresholds across the
outer coastal waters by Wednesday evening.
Long term /Thursday through Saturday/...
as of 325 PM Monday...latest models holding frontal passage back again until
around noon time on Thursday. Therefore will keep S-SW winds in the
forecast through Thursday morning with seas up to 3 to 6 feet. Should see
an fairly abrupt wind shift from SW to north behind front on Thursday.
Strong cold air advection and tightened gradient will keep seas up to 4 to 7 feet
through Thursday night. The front will linger to the south as high
pressure builds down into the waters from the northwest. This should keep a
prolonged period of Small Craft Advisory conditions in strong northerly winds through
Thursday into Friday. Winds will lighten through late Friday and become more
variable into the weekend as high pressure weakens as it shifts
closer overhead and then off the middle Atlantic coast. May see a wave
of low pressure move along the southeast coast on Saturday...but
overall expect winds to lighten and seas to drop below Small Craft Advisory by Friday
afternoon and down to 3 feet or less over much of the weekend.
Marine...Small Craft Advisory until 7 am EST Tuesday for amz250-252-254-