Scientific Forecaster Discussion
fxus61 klwx 200901
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
401 am EST Wed Nov 20 2019
High pressure will build in from the west through Thursday. A
cold front will move across the region Friday afternoon. A low
pressure system will approach the area late Saturday into
Near term /through tonight/...
An upper level trough of low pressure will pivot across the region
today and tonight. There could be some upslope rain or snow showers
in the Potomac Highlands mainly through midday today. High pressure
will build in from the west later today and tonight before moving to
the East Coast later tonight. High temperatures today will be a
little cool based on the cloud cover and a gusty northwest breeze
that will advect cooler and drier air into the region. Lows tonight
will be seasonable.
Short term /Thursday through Friday night/...
High pressure and ridging aloft will reside over the eastern
Seaboard throughout the day Thursday. Highs Thursday will be near
normal as winds back around from the northwest to the south. Low
pressure will track northeastward from the central U.S. Into the
Great Lakes, lifting a warm front through the mid Atlantic region
Thursday night. A few showers will be possible Thursday night as a
A cold front will move across the region on Friday. While the
morning hours on Friday look to remain mostly dry,especially for the
Metro area, anticipate showers developing by the early afternoon
over the Appalachians with spotty showers persisting throughout the
remainder of the day elsewhere.
Long term /Saturday through Tuesday/...
Strengthening low pressure over the Tennessee Valley will spread rain
back into the area Saturday into Saturday night. Initially,
there is an in-situ cold air damming signature in the mslp
pattern and 1000-850 mb thickness lines which may result in some
light freezing rain at higher elevs at onset of precip. GFS soundings
show wet-bulb temperatures below oc between 1-3 kft Saturday
afternoon. November is also a notorious month for having
surprising ice storms on Skyline drive and at other high elev
locations. Low pressure moves offshore by 12z sun with precip
ending late Sat night. Then, high pressure over the region
during the first half of next week keeping fair weather
Aviation /09z Wednesday through Sunday/...
VFR conditions through Thursday night as high pressure builds in
from the west and slides east to the East Coast ahead of a cold
front. The cold front is expected to slice across the region and
bring a wind shift to the northwest and gusty. MVFR conditions
possible with rain showers Friday into Friday evening. Winds
northwest 10 to 15 knots gusts 20 knots today, diminishing tonight.
Winds northwest backing to the south around 10 knots Friday into
IFR conditions appear likely on Saturday in rain as low pressure
tracks across the area. Then, gusty northwest winds 20-25 kt late Sat
night into Sunday.
Small craft advisories are in effect today into most of tonight.
Small craft advisories may return on Friday with a gusty southwest
breeze becoming northwest late Friday.
Small craft advzy conditions likely late Sat night and Sunday.
Anomalies are dropping and no more cf.Y needed.
District of Columbia...none.
Marine...Small Craft Advisory from 9 am this morning to 6 PM EST this
evening for anz530>543.