Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 klwx 051518 cca 
afdlwx

Area forecast discussion...corrected
National Weather Service Baltimore Maryland/Washington District of Columbia
1018 am EST Thu Dec 5 2019

Synopsis...
high pressure will build toward the mid-Atlantic from the
southern U.S. Through tonight. On Friday, a cold front will
cross the region from the west. Another area of high pressure
will follow for the weekend. The next low pressure system will
approach early next week.

&&

Near term /through tonight/...

No real changes to the near term from the previous discussion.

Noting isolated snow flurries on radar moving through northern Maryland
under a northwest flow, although it does not appear that anything
measurable is reaching the ground. With the high continuing to move
overhead, increasing subsidence should suppress any residual flurry
activity. With good mixing through the bl, expect gusty northwest winds up
to 35 mph to persist throughout the afternoon, before relaxing
tonight. Air temperatures will rise into the 40s to lower 50s,
though the wind will make it feel chillier.
The high will build across the southeastern states tonight,
allowing winds to diminish. Low temperatures will be in the
upper 20s to lower 30s, though mid/high clouds could thicken
enough to keep it a bit warmer.

&&

Short term /Friday through Saturday night/...
a weak area of low pressure will move through the Great Lakes on
Friday, with a trailing cold front crossing during the afternoon
or early evening. Shortwave troughs will be located well to our
north and south, and westerly flow off the surface will promote
low level drying east of the Appalachians. Thus not expecting
much precipitation with this system, though there could be some
light showers along/west of the Appalachians. These showers
would mainly be rain, but could end as snow. There will be a bit
of a warm up ahead of the front, with highs in the upper 40s and
lower 50s.

Behind the front, a large/strong area of high pressure
originating from Canada will build in to start the weekend.
Gusty winds Friday evening will diminish by Saturday. Cold
advection will result in lows below freezing in many areas and
highs in the 40s.

&&

Long term /Sunday through Wednesday/...
high pressure will move east and offshore from the New England coast
on Sunday while flow remains zonal aloft. Winds will become
southerly on Sunday, and this will advect warm and moist air into
our region. Return flow, the increase in moisture and shortwave
energy aloft will increase the chance for showers Sunday night into
Monday.

A low pressure system over the Great Lakes will push its associated
cold front eastward late on Monday. The front will be moving across
our area on Tuesday. Chance of showers will continue Monday night
into Tuesday while southerly flow continues to advect moisture into
our area. Trough axis aloft will move across on Wednesday while
surface high pressure starts building east and overhead into
Thursday.

&&

Aviation /14z Thursday through Monday/...
as an upper level disturbance exits this morning, the risk of
any showers is quickly ending. Ceilings are in the VFR range,
and should scatter out as the day progresses. Northwest winds have
increased, with some gusts of 25-30 knots persisting through the
day. Winds will diminish with sunset as high pressure builds south
of the area tonight.

A cold front will cross the area Friday afternoon or early
evening but will likely be dry. Gusty northwest winds greater
than 20 kt are possible in its wake. No significant weather
later Friday night through Saturday night with high pressure.

VFR conditions expected for Sunday into Sunday night. Chance of
precipitation increases late Sunday night and remains through
Tuesday. Periods of sub-VFR conditions are possible during this
time.

&&

Marine...
gusty northwest winds will continue to uptick this morning and continue
into early this evening. A Small Craft Advisory is in effect
for all waters today, and did extend until 9 PM for the wider
waters since it could take some time for winds to subside. Gusts
of 20 to 30 kts are likely. With high pressure to the south
later tonight, winds will subside.

A cold front will approach Friday and push to the east Friday
evening. Mixing ahead of the front is questionable, so did not
have the confidence to issue a late third period advisory. Some
of the waters will likely need an advisory Friday night with a
surge of gusty northwest/north winds.

High pressure will build overhead for Saturday through Saturday
night with lighter winds expected.

Sub-Small Craft Advisory conditions expected Sunday into Monday over the waters.
Small Craft Advisory may be needed on Tuesday with an approaching cold front.

&&

Lwx watches/warnings/advisories...
District of Columbia...none.
Maryland...none.
Virginia...none.
WV...none.
Marine...Small Craft Advisory until 9 PM EST this evening for
anz531>534-537>543.
Small Craft Advisory until 6 PM EST this evening for anz530-
535-536.

&&

$$
Synopsis...ads
near term...bjl/ads/mss

National Weather Service Glossary of Abbreviations