Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
446 am EDT Tuesday Sep 30 2014
a trough of low pressure will move off the coast this morning. An
upper level low pressure system will swing across southern New
England and off the coast tonight into Wednesday night...pushing
a weak cold front through the local area. High pressure builds
into the middle Atlantic region on Thursday...then another cold front
approaches from the west Friday.
Near term /until 6 PM this evening/...
precipitation was moving off the CST early this morng...and a trough of low
pressure will follow out to sea during this morng. But...will have to
deal with areas of dense fog and stratus across much of the region
through 8 or 9 am...due to moist ground and very light or no wind. The
rest of today...forecast area will be located in between departing trough
surface-aloft offshr...and a stronger upper level trough pushing southeast from the
Great Lakes. Sky should become at least partly sny for later this
morng through this afternoon with light NE or east winds. Maximum temperatures will be 75
Short term /6 PM this evening through Thursday/...
upper level low pressure will swing across southern England and off the CST tonight
into Wednesday night...pushing an associated trough surface-aloft through the forecast
area with broken cloudiness and mainly slight chance probability of precipitation (mainly north-northeast
portions). Otherwise...variable clouds to prtly cloudy. Low temperatures
tonight will range from the middle 50s to the lower 60s. Hi temperatures on Wednesday
will range from the lower to middle 70s on the eastern shr...to the upper 70s
to lower 80s elsewhere.
Hi pressure from New England builds southward into the region later Wednesday
night through Thursday...resulting in another period of east-northeast winds. Models
suggest that inland locations have a low probability for isolated
showers (thu morng) along with variable clouds. Mainly prtly
cloudy toward the CST. Low temperatures Wednesday night will range from the middle 50s to
the lower 60s. Hi temperatures on Thursday will range from the middle 70s to around 80.
Long term /Thursday night through Monday/...
the long term period will feature a progressive pattern with a
continuation of short waves moving through the northern stream.
Following the upper level in the middle of this week...an upper
level ridge will be over the Middle Atlantic States Thursday night and
Friday. The next weather maker will be associated with a cold front
which approaches from the west Friday.
Models are rather consistent with the timing of the front to move
into the County Warning Area Friday night and off the coast early Saturday morning.
Have 50 percent chance for showers across the County Warning Area beginning western
portions Friday evening and across the Eastern Shore during the
pre-dawn hours Saturday morning. Went no higher than 50 percent but
as confidence in the event increases...future issuances will
probably have likely probability of precipitation. Currently wpc has one quarter to one half
inch quantitative precipitation forecast with the main part of the precipitation probably lasting about six
hours at any location.
Friday will be the warmest day of the long term with high
temperatures near 80 inland and middle 70s near the coast. Highs in the
upper 60s to middle 70s are expected Saturday through Monday except on
Sunday when highs should be mainly middle to upper 60s. Lows in the upper
50s to lower 60s Friday and Saturday morning lower to the upper 40s to
middle 50s Sunday and Monday mornings.
Aviation /09z Tuesday through Saturday/...
IFR/local LIFR across Piedmont terminals this morning, with low end
VFR/MVFR across coastal terminals as a weak trough of low pressure
continues to shift offshore early this morning. With clearing
beginning inland, expect IFR at ric, with a period of LIFR after
09z-13z. Farther east, light rain will linger through 07-09z at
orf/phf/sby/ecg...with a brief period of IFR ceiling/visibility as
clearing ensues towards daybreak. A return to VFR is expected
after 15z at all terminals.
Outlook...dry weather is then indicated for the rest of the work week.
But...will need to consider areas of fog or stratus around sunrise
latest observation reflect light north-northwest winds at or below 10kt across the waters this
morning. Weak surface trough will slide offshore this morning.
Meanwhile, surface low pressure will develop off the southeast coast today and
tonight. North-NE winds 5-10 knots today will increase to 10-15kt tonight
as gradient tightens offshore. Seas will increase to 3-4 feet late
tonight/early Wed, highest over offshore waters. NE winds remain
sub-Small Craft Advisory Wednesday/Thu, though nwps/wavewatch both increase seas into Small Craft Advisory
range Thursday/Friday. Have held off with Small Craft Advisory flags for the moment
with conditions still appearing marginal at this time. Winds veer around to
the S-SW Friday night and early Saturday ahead of a strong cold
front, which crosses into the area early Saturday, with winds
quickly swinging around to the northwest Post-front Saturday evening. Winds
and seas diminish Sunday into Sunday evening.