Scientific Forecaster Discussion
fxus61 kakq 121742
Area forecast discussion
National Weather Service Wakefield Virginia
1242 PM EST Thu Dec 12 2019
high pressure builds over the area today before pushing off to
the northeast by this evening and overnight. Low pressure
develops along the Gulf Coast on Friday, then tracks northeast
along the eastern Seaboard over the upcoming weekend.
Near term /until 6 PM this evening/...
as of 1230 PM EST Thursday...
Sfc high pressure slowly pushes off to the northeast through
the day today. It will be a chilly day today with temperatures
only rising into the low to mid 40s (normal highs are in the
low/mid 50s). Sunny/mostly sunny most areas, except
overcast/becoming overcast for far southeast Virginia and coastal NE NC as
a deck of stratocumulus moves in off the ocean.
Short term /6 PM this evening through Saturday/...
as of 400 am EST Thursday...
The high pushes off the New England coast tonight. Moisture from a
developing system to the south-southwest increases along a sfc trough in
vicinity of the mountains while additional moisture is noted along a
Carolina coastal trough. Dry air in the lower levels will initially
keep most areas pcpn-free with the exception of some rain creeping
along the immediate coastline and Maryland Eastern Shore (pops
~20%). Slight to chance pops are also in the forecast for areas
mainly west of I-95 during the 09-12z timeframe Friday. Thermal
profiles continue to indicate the potential for this precipitation
to begin as a period of freezing rain (ip across the northwest where there will be
colder temperatures aloft). The chance to see a period of freezing rain/ice pellets will
continue across the northwest until around 15z before transitioning to all
rain. Only minor ice accumulations in the forecast(generally ~0.02"
or less) for these areas, but a Winter Weather Advisory may still be
needed due to the freezing rain potential. Will let the afternoon
shift decide if an advisory is needed based on the latest model
Warm air advection moisture will continue to overspread the area from the south-southwest
through the day on Friday, staying as plain rain for all areas minus
the aforementioned far northwest/west locations. Deepest moisture arrives
later in afternoon Friday into the overnight hours with likely to
def pops in the forecast for this timeframe. Up to an inch of quantitative precipitation forecast is
in the forecast across the west, tapering down to around a half of
an inch closer to the coast. Temperatures will vary widely from northwest
to southeast during the day on Friday due to the in-situ wedge setup with
highs ranging from around 40 across the northwest to near 60 across the
Low pressure lifts NE and away from the mid-Atlantic region on
Saturday. However, upper level energy rotating in from west-northwest will
generate additional rain chances, especially through the morning.
Pops continue to trend lower in the afternoon with potential dry
slot arrival. Highs from the low 50s northwest to the low 60s southeast.
Long term /Saturday night through Wednesday/...
as of 400 PM EST Wednesday...
Low pressure will continue to move northeast away from the area
Saturday, across the Hudson River valley and into Quebec. Winds
will turn northwest behind the low pressure system producing a
downslope flow off of the mountains beginning Saturday night,
quickly drying the area out. There will only be weak cold air
advection as the low moves north, therefore temperatures will
remain mild. Saturday and Sunday night temperatures will be in
the mid 30s to mid 40s. High temperatures will be in the low to
mid 50s on Sunday.
Another low pressure system will develop over the Gulf Coast
states Sunday night and track east as an upper trough amplifies
over the central Continental U.S.. the GFS has the center of the low
pressure tracking inland, west of the Appalachian Mountains,
while the Canadian and European model (ecmwf) have a low pressure track northeast
into the southern appalachian Monday night and developing a
secondary low pressure system somewhere across eastern NC or
eastern Virginia early Tuesday morning. The forecast leans towards the
European model (ecmwf) and Canadian track. There will be a chance of a rain/snow
mix across the northern portions of the forecast area at the
onset of the precip Monday morning before a widespread area of
rain moves in with the warmer air Monday night.
Temperatures will warm from south to north Monday night with
lows in the mid 30s north and low 50s south. With the center of
the low pressure tracking over the area, high temperatures on
Tuesday will range from the upper 40s in the Piedmont and upper
50/low 60s close to the coast. Cold front will move through
behind the low pressure with colder air moving in with high
Aviation /18z Thursday through Tuesday/...
as of 1230 PM EST Thursday...
Stratocu moving in off the ocean will allow for borderline MVFR
ceilings at the southeast terminals this afternoon into tonight.
Otw, clouds increase from southeast to northwest late this afternoon into
this evening. Ceilings are then expected to lower to low end
MVFR or IFR early Friday morning (starting 10-12z), especially
for kric/ksby as the next system approaches the region. Pcpn
mostly in the form of rain will then overspread the entire
region from SW to NE during Friday. Winds generally remain light
(5-10 knots) from the north to NE through the forecast period.
Outlook...the next system brings rain and degraded flight
conditions Friday afternoon through Saturday. The
heaviest/steadiest rain is expected Friday night through
Saturday morning. A gradual return to VFR conditions expected
later Sat, with VFR conditions expected Sunday into early next
as of 130 am EST Thursday...
Strong sfc high pressure (~1037 mb) currently building S into
the waters early this morning. Strong low level cold air advection is
overspreading the waters and seeing gusts in the Bay to 25-30
kt. Have added the lower James River to the Small Craft Advisory headlines that
had already been in place across the Bay/ocean/sound. For the
rest of the river zones, issued a short fused mww to cover ~2
hrs Worth of gusts to 20-25 kt with expectation that this will
be short lived. Sfc high settles over the area late this morning
through the remainder of today with diminishing winds but seas
will remain elevated (especially southern coastal waters) into
the aftn or evening.
Sfc high pressure drifts off to the NE tonight. Low pressure
develops along the Gulf Coast Fri then tracks NE to the mid-
Atlantic states by Sat morning. Seas on Sat may flirt with 5 ft
offshore but overall sub-Small Craft Advisory conditions are anticipated. A
period of stronger winds and additional headlines does look
late Sat/Sat night/early Sunday as the sfc low intensifies off
the New England coast/Atlantic Canada with high pressure
building in from the west.
Marine...Small Craft Advisory until 7 PM EST this evening for anz656.
Small Craft Advisory until 10 PM EST this evening for anz658.