Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
1248 am EST Wednesday Dec 11 2013
high pressure builds in from the west overnight and settles over
the southeast Wednesday. A dry cold front moves through the region
Wednesday night...with high pressure building back into the middle
Atlantic Thursday. High pressure settles off the coast Thursday
night and Friday.
Near term /through today/...
latest weather analysis places surface cold front now well off the middle-
Atlantic coast, extending southwest just off the coastal
Carolinas. To the west, ~1030mb surface high pressure over the
Tennessee Valley was building across the central and southern
Appalachians early this evening.
Strong cold air advection behind the front has promoted quick clearing over the
past few hours...and 00z observation reflect temperatures that have already
plummeted into the upper 20s and low 30s across northwest zones. A
similar trend is expected over the rest of the area through
midnight as the high eventually centers over the Appalachians late
tonight, and settles over the southeast on Wednesday. A clear sky
and light wind will allow early morning lows to drop into the
lower 20s from the Piedmont to the Eastern Shore...W/ upper 20s
to around 30 far southeast. The low-level flow becomes southerly
Wednesday afternoon. However...mixing will be limited and highs
should range from the upper 30s NE...to middle/upper 40s SW.
Short term /tonight through Friday/...
a dry cold front moves through the middle Atlantic Wednesday
night...which Ushers in a colder high. 850mb temperatures drop to
around -12c Thursday over NE portions of the area...with around -6c
over SW portions. This should support highs ranging from around 32
NE...to the low 40s S/SW. Highs should rebound a few degrees Friday
as the high moves off the coast. Mixing will be limited...which will
hamper a more substantial warm-up. Highs should range from the low
40s NE...to the middle/upper 40s SW. Lows Thursday and Friday morning
should largely range from the low to middle 20s.
Long term /Friday night through Tuesday/...
12z GFS and 12z European model (ecmwf) in generally good agreement for the extended
period...with temperatures expected to remain at or below normal. Low pressure
will then track from the middle/lower MS valley late Friday night...NE to just
off the New Jersey CST by sun morng. This low and an associated cold front
will bring more rain to the region Sat through Sat night. The precipitation will
end over southeast cnties early sun morng...as the front pushes out to sea
early Sun afternoon. Hi pressure will build back into and over the area for late
Sun night into Tuesday. Min temperatures will be in the upper 20s to lower 30s Sat
morng...range from the lower 30s to the middle 40s sun morng...then range
from the lower 20s to the lower 30s Monday and Tuesday morngs. Maximum temperatures will
range from the lower 40s northwest to the upper 50s southeast Sat...range from the middle 40s
to middle 50s sun...range from the upper 30s to middle 40s Monday...then range
through the 40s Tuesday.
Aviation /06z Wednesday through Sunday/...
cold front has pushed well offshore tonight as high pressure
builds in from the west. Moisture has also scoured out as dew
points continue to drop into the middle-upper 20s. This will be the
trend through early Wednesday morning...further limiting fog development
regardless of good radiational cooling (clear skies) and wet
soils. The exception will be along the immediate coast...but
expect ksby to remain VFR through Wednesday morning. Otherwise...weakening
gradient will produce westerly winds at or below 10 knots.
For today...expect sunny skies except for few-scattered passing high
clouds at or above 25k feet this afternoon. As high pressure nudges in...surface
winds will become northwesterly this afternoon before high pressure moves
offshore...backing the winds to the SW. However...winds will
remain at or below 10 knots.
Outlook...a stretch of dry/VFR weather conditions is expected
Thursday/Friday with a chance of rain returning over the weekend.
1am update...latest observation show seas dropping below 5 feet in the southern
coastal waters...so will allow the last of the Small Craft Advisory headlines to
expire. As high pressure nudges in from the west-SW and cold air advection begins to
wane...a brief uptick in winds is possible over the Bay as a few
gusts of 15-18 knots is possible...especially in the Lower Bay. Small Craft Advisory
headlines are not anticipated at this time.
northwest winds will diminish this eveng/ovrngt...as hi pressure
builds into and over the area. Winds become SW less than 15 knots for
Wednesday into Wednesday eveng...as the hi slides offshr. A dry cold front
crosses the waters Wednesday night...with strong northwest winds and sca's expected
again late Wednesday night through Thursday. Calmer conditions will prevail Thursday
night through Friday...as hi pressure builds over the area then offshr.
dox radar remains down until further notice due to comms problems.
Local telco continues to work on the problem. Further updates will
be passed along as they become available.