Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington NC
221 PM EDT Wednesday Sep 2 2015
above normal temperatures are expected through Friday. A weak
trough will linger inland through early Friday. A ridge of high
pressure will build in from the north behind a cold front by this
weekend...bringing cooler temperatures through early next week.
Near term /through tonight/...
as of 200 PM Wednesday...a Summer like air mass holding over the
area today with weak high pressure maintaining light and more
variable winds. With strong heating and decent downslope flow
through the low levels...temperatures soared above 90 most places...with
sea breeze dominating this afternoon near shore. As the sea
breeze pushes slowly inland slowly it will remain the Focal Point
for low level convergence...but plenty of dry air aloft will keep
showers at Bay for the most part. Overall...expect flatter cumulus to
mix with mainly sunny skies across the area.
Moisture will increase gradually through the atmosphere into
tonight....mainly visible in the middle to upper levels due to a
shortwave tracking down from the northwest. Models show associated
convection with shortwave upstream over NC/Virginia border early this
evening then diminishing as it reaches our northwest County Warning Area boundary late
evening...closer to midnight. Therefore may see a few stray
showers/thunderstorms reach our northern tier but overall expect mainly
clouds moving down over the area. Temperatures holding up in the 70s most
places overnight in a warm and humid air mass.
Short term /Thursday through Friday night/...
as of 230 am Wednesday...500 mb ridge will build far north into the
plains and MS valley while a trough resides across the eastern
United States during Thursday. As the 500 mb ridge builds farther
northeast toward the Great Lakes the trough remains situated over
our region. At the surface...a poorly defined inland trough will
push off the coast Friday as high pressure ridges into the area from
the north late Friday. The highest precipitable water remains
displaced south of the forecast area and low-level moisture
transport is lacking in the short term. A decent lifting mechanism
is also lacking as well thus primarily kept probability of precipitation in the 20-30% range
most locations with the sea breeze and only a weak inland trough to
work with some instability. Above normal temperatures expected each
day...with the warmest readings to occur Thursday (lower 90s
coastal areas to the middle 90s farther inland).
Long term /Saturday through Tuesday/...
as of 230 am Wednesday...increasing cloud cover expected as a
surface ridge builds in from the north. This pattern will result in
below normal maximum temperatures Saturday through Tuesday...while low
temperatures remain at...or slightly above normal. Unsettled weather
possible during the long term...especially Sunday through Tuesday as
a broad/weak upper low may evolve and slowly drift across the south.
At this point it is difficult to time the best chances for rainfall
or when moisture availability will be at its greatest...but the
trend is for increasing probability of precipitation by Sunday. The pattern may begin to
break down by middle-week with a return of warmer temperatures and lower probability of precipitation.
Aviation /18z Wednesday through Sunday/...
as of 18z...light west-southwest-northwest winds will become S-SW early this afternoon
with VFR conditions through this evening. Skies will be generally
scattered this afternoon with middle level ceilings possible at times at
kflo/klbt this evening and overnight. Winds become light and
variable or light SW-west this evening. There is a chance of showers
northern terminals after midnight. Activity should remain isolated
thus have not addressed in tafs. In the pre-dawn hours MVFR visibilities
are again possible at the inland terminals. The chance of IFR is low
due to cloud cover however since klbt may scattered in the pre-dawn hours
if IFR occurs it will be there. VFR after sunrise with west-northwest winds.
Extended outlook...predominately VFR with brief morning fog and
isolated/scattered afternoon showers and thunderstorms.
near term /through tonight/...
as of 200 PM Wednesday...a trough will be strung out from west to
east south of our local waters but weak high pressure will hold
locally through today. Basically flow will be dominated by the
sea breeze this afternoon with on shore gustier winds...basically
se-S. With winds generally 10 knots or less...seas will remain 2 feet
Short term /Thursday through Friday night/...
as of 230 am Wednesday...a weak boundary near the coast Thursday
will push offshore during Friday as a ridge begins to build south.
As a result...variable winds early Thursday will become southerly
in the afternoon and evening. The wind will gradually veer to a
northeasterly direction late Friday night as the aforementioned
ridge builds in. Seas will be 2 feet or less through the short term
Long term /Saturday through Sunday/...
as of 230 am Wednesday...seas will increase during Saturday as
northeast fetch becomes better established with ridge building in
from the north. Seas 3-5 feet are possible for the Cape Fear waters by
Saturday aftn/eve. Northeast to east winds will prevail Sunday with
seas 3-4 feet. Potential for scattered showers/thunderstorms each day.