Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington NC
327 am EDT Thursday Oct 2 2014
high pressure ridging south across the area will move offshore
tonight into Friday morning. A strong cold front will move across
the area Saturday morning. Dry and cool high pressure will follow
for the weekend and persist into early next week. A warming trend is
expected for the middle of next week.
Near term /through tonight/...
as of 3 am Thursday...a weak impulse aloft is helping to generate
a scattered-v-bkn deck of middle clouds across the Carolinas. These clouds
will hinder fog development in some locations...otherwise another
morning with fog and stratus in on tap. The weak surface ridge axis
in place across the region will slowly drift east through tonight.
Could be enough lift to spark an isolated shower today but moisture
availability is rather restricted...and a weak sea breeze will not
be much of a player. 500 mb ridging will gradually take control tonight
and with mostly clear skies and light wind have lowered mins a
category. Fog will once again be possible during the overnight.
Short term /Friday through Saturday night/...
as of 3 am Thursday...the cold front associated with a major pattern change
remains on track to move across the area late Friday/early Saturday.
I have increased probability of precipitation slightly to address increasing confidence. For
Saturday...guidance has warmed dramatically as the cold air
advection is delayed even further warranting a marked increase in
highs for Saturday...now approaching 80 for most areas. Much cooler
Sunday with lows in the 40s for most areas and highs not eclipsing
the 70 degree mark. Monday morning looks to be the coolest via ideal
radiational conditions with 40s County Warning Area wide.
Long term /Sunday through Wednesday/...
as of 3 am Thursday...the northwest flow will continue Sunday on the
order of 10-15 knots. Late in the day the flow will shift to the
southwest as high pressure realigns off the Carolina coast. This
flow will continue through the day Monday. Wind speeds drop down to
around ten knots. Significant seas will be 1-3 feet.
Aviation /07z Thursday through Monday/...
as of 06z...still expect areas of MVFR/IFR fog to develop in the
pre-dawn hours...as mostly clear and calm conditions will allow for
good radiational cooling overnight. Have pushed back the timing of
the fog a bit at the inland terminals given the lingering debris
clouds from earlier isolated showers. MVFR visibilities will become
increasingly likely at all terms after 08-09z...with tempo IFR at
klbt/kflo from 09-12z. Forecast soundings indicate the low level
moisture is fairly shallow...so visibilities could bounce around between
MVFR/IFR levels before daybreak. Brief periods of IFR could develop
at kilm/kcre before 12z...but confidence is lower than for the
inland sites. VFR will prevail during the day with light/variable winds
becoming south around 5 knots in the afternoon. Expect clear and calm
conditions again after 00z Friday...but any visibility issues should hold
off until after the valid period.
Extended outlook...MVFR/IFR visibilities possible early Friday morning.
Showers and a chance of thunderstorms/MVFR late Friday/early Sat with a cold
front. Otherwise VFR.
near term /through tonight/...
as of 3 am Thursday...excellent boating conditions through tonight
with a weak pressure gradient in place across the waters. The flow
will turn onshore today as the sea breeze develops and pushes inland
however...speeds should be 10 kts or less. Seas will be around 2 feet.
Short term /Friday through Saturday night/...
as of 3 am Thursday...southerly winds will quickly pick up in
intensity through the day Friday with a 15-20 knot range by days
end. The flow will veer slightly to southwest Friday night and
increase by a couple of knots before the cold front moves across
Saturday morning. It appears winds and seas will stay just below
small craft criteria. Saturday will see winds subside and turn to
the northwest. Seas diminish from 3-5 feet late Friday into early
Saturday to 2-4 feet by late Saturday.
Long term /Sunday through Monday/...
as of 3 am Thursday...the extended period will be very tranquil
as the deep cyclonic flow prevails basically through the period.
High pressure moving from the southwest to off the East Coast will
be the main surface feature. There is a decent shortwave riding
down in the main flow that may provide some showers across the
Tennessee Valley but the limited moisture should not make it to
the coastal plains. Temperatures will start out the period with
highs in the 70s and lows in the 50s. By Wednesday expect lower
80s for highs with 60s for lows along the coast with 50s inland.