Scientific Forecaster Discussion
fxus61 klwx 222037
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
337 PM EST Wed Nov 22 2017
in the wake of a passing cold front earlier this morning, high
pressure will nudge its way in to the region through early Friday.
Another cold front will approach overnight Friday into Saturday
before passing through Saturday night. High pressure returns for
Sunday and Monday. A Small Craft Advisory may be needed for the
waters late Saturday and Sunday.
Near term /through tonight/...
a cold front passed through the area this morning, leaving
behind gusty northwesterly breezes in its wake. Scattered
stratocumulus clouds have filtered in across north central MD,
northern VA, and the WV Panhandle. Temperatures topped out
earlier this morning in the mid to upper 50s, but cold air
advection behind the front have dropped temperatures in to the
lower 50s in the Metro areas and in to the 40s across the
western portion of the County Warning Area.
Winds will diminish a couple hours after sunset this evening as
the gradient relaxes thanks to high pressure building in from
the lower Great Lakes and Ohio Valley region. With diminishing
winds, building high pressure, and clear skies, radiational
cooling will allow temperatures to settle in the lower 30s in the
city centers and well in the 20s to the west and north. Despite
the colder than average temperatures for late November, optimal
driving conditions are in store for those travelling for the
Short term /Thursday through Friday night/...
high pressure will continue to build overhead for Thanksgiving
day and Thanksgiving night, resulting in below normal
temperatures and dry conditions. High pressure will shift
eastward off the Delaware-Maryland-Virginia peninsula Friday, allowing winds to
turn more southerly, which will help temperatures return to more
seasonable levels with highs in the low-mid 50s and low
temperatures Friday night in the mid-upper 30s for most.
Long term /Saturday through Wednesday/...
a cold front will approach from the west on Saturday, with
an upper trough over the eastern Continental U.S.. slight rain chances
will be possible Saturday across the western and northern
portions of the County Warning Area as the primary energy will remain to the
north. At the same time a coastal low pressure system will be
moving northeast away from the Carolina coast. At this time,
little to no impact is forecast for our area, however should
this low move a further northwestward, southeastern portions of
the region could see some rain showers. Behind the frontal
passing, snow showers will be possible along the typical higher
terrain locations, with little to no accumulation expected.
Surface high pressure builds on Sunday as an upper trough axis
moves east of our County Warning Area. Chilly, breezy, and mostly dry
conditions will prevail as any remaining upslope snow showers
will wane. Sunday will highlight colder than average
temperatures, with most locations not getting out of the 40s,
and overnight lows Sunday night similar to tonight. Monday will
see high pressure move eastward from the Ohio Valley, migrating
off the coast late Monday. With the upper level trough just
exiting the region, temperatures will be slightly warmer Monday,
yet still below average for late November. Dry conditions
Southwest flow returns on Tuesday thanks to the migration of
the high to our east, returning temperatures to mid-upper 50s,
and breaching the 60 degree mark on Wednesday. Models are in a
bit of a disagreement with an approaching cold front Wednesday,
so will continue to monitor this situation over the next couple
of days to Iron out the details and timing.
Aviation /19z Wednesday through Monday/...
gusty northwesterly winds expected to decrease this evening a
couple hours after sunset. Scattered stratocumulus clouds that
have moved in behind the front this afternoon should dissipate
this evening as drier air filters in. VFR conditions will
prevail across all the terminals for Thanksgiving day and Friday
as high pressure builds overhead.
Mainly VFR conditions expected Saturday, with precipitation
possible later that day as a cold front approaches the area.
Potential exists for periods of MVFR conditions Saturday
afternoon and evening. Drier/VFR conditions expected Sunday
into Monday over the terminals.
a Small Craft Advisory remains in effect for the coastal waters
tonight as gusty northwesterly winds will start to subside
toward Thursday morning. No headlines expected thereafter
through Friday night as high pressure builds in overhead.
Winds are expected to stay below threshold on Saturday
into Saturday night as cold front moves through the area. Winds
will increase on Sunday into Sunday night, therefore small
craft advisories will be possible. Winds will decrease below
Small Craft Advisory threshold on Monday.
District of Columbia...none.
Marine...Small Craft Advisory until 6 am EST Thursday for anz531>534-
Small Craft Advisory until 6 PM EST this evening for anz530-