Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
1016 PM EST Wednesday Feb 10 2016
high pressure will build into the middle Atlantic through Friday. A
strong cold front will cross the region Friday night. Arctic high
pressure then builds in for the weekend. Low pressure may impact
the area Monday and Tuesday.
Near term /until 6 am Thursday morning/...
upper shortwave which brought snow showers to areas mainly south
and southeast of the district this evening is heading east and the
snow showers have ended. A few flurries may linger but generally
think the area is dry for remainder of the night. Winds will
remain gusty as cold air advects into the area behind it.
In the west the upslope snow machine remains on. Blv the upslope region snow
activity will continue through the night. Winter Weather Advisory remains in effect.
There is also a Wind Chill Advisory in effect for higher elevs.
Majority of area will see lows below 20 tonight...and higher elevs will see
temperatures fall into the single digits. This will translate at higher
elevs to winds chill below negative 10...single digits west of I-95.
Short term /6 am Thursday morning through Friday/...
cyclonic upper level pattern over the eastern U.S. Will weaken Thursday into Friday.
Skies should see plenty of sunshine during Thursday but temperatures will still be
cold - highs primarily a30s.
No probs expeceted Thursday night west/ high pressure over the area. Another chilly
night although winds will be light. Lows in the teens expect single digits in
Clouds will be on the increases Friday ahead of a fnt which will be ushering in
very cold air to the region. Snsh could be possible during the afternoon in the
west. Highs in the m30s.
Long term /Friday night through Wednesday/...
two main concerns for Friday night-Saturday as an Arctic cold front
swings through. The first is snow showers. There will be an enhanced
upslope component and several inches of snow will be possible. With
a deep moist layer...some snow showers will be able to move east of
the mountains as well but accumulations look light/scattered at this
time. The main time frame for these would be Friday night...but
there could be a renewed chance of at least flurries across the
northern tier Saturday with deep mixing and convective clouds. The
other concern will be increasing winds and cold temperatures. The winds do
not look to reach advisory level at this time (perhaps close in the
high terrain)...although some 30-40 miles per hour gusts certainly possible.
However...they will drive wind chill values down. Behind the
front...850 mb temperatures will be below -20c. Lows Friday night will be
in the teens and highs Saturday only in the teens and 20s. The wind
chills will drop into the single digits (below zero at higher
elevations) west and teens east and stay there through the day
A major Arctic outbreak looks imminent during the second half of the
weekend. A large area of high pressure originating from directly
over the North Pole will barrel over the eastern half of the nation
in the wake of a cold front on Saturday. 850 mb temperatures drop to
around -25 c overnight Saturday night likely pushing low temperatures down
into the single digits possibly even into the cities...with lows
below zero likely in the higher elevations. Winds will be blowing as
well as the cold air rushes into the region with wind chills well
below zero a good bet area wide.
The airmass begins to moderate Sunday into early next week...but
Arctic airmasses of this caliber rarely go quietly.
Subsequently...guidance unanimously hints at a storm system
approaching as the cold air retreats...but differences in timing and
track/strength make the ultimate outcome of potential wintry weather
uncertain especially east of the Blue Ridge mountains. Western parts
of the area have the best chance of an impactful winter storm Monday
into Tuesday...with more uncertainty towards the metropolitan areas where
the timing of warmer air moving in will be crucial to ptype. Of
note...the large Arctic high retreats to the east and sets up over
the North Atlantic...as opposed to the northeast over southeastern
Newfoundland which would be the most favorable for locking in colder
air. There is still plenty of time for change though so this system
bears close monitoring especially considering potential phasing and
plenty of moisture available.
Aviation /03z Thursday through Monday/...
VFR conds rest of night and continuing Thursday and Thursday night with cold
dry air advecting southeast into the area on gusty northwest winds. Ceilings
mainly 5kft and above...generally breaking up by later Thursday with
mostly clear skies Thursday night as winds relax.
VFR will prevail Friday night-Saturday...although there could be a
brief snow shower or period of flurries. Winds will increase
markedly with gusts to around 30 knots possible late Friday night into
Gusty northwesterly/northerly flow Sat night-sun 15-25 g 35 knots...with gusts
possibly passing 40 kts at times. VFR likely. Sub-VFR possible early
next week as low pressure approaches. Winds uncertain depending on
track...but predominately Ely.
Small Craft Advisory in effect for all of the waters through Thursday night.
However...winds may relax for a time Thursday night and Friday
Cold front passes Friday night with increasing northwest winds. Will
continue to forecast potential gales for Saturday...especially on
the Open Bay.
Gales are likely Saturday night into Sunday morning as
strong high pressure surges into the area. Freezing spray is likely
as well given the robustly cold airmass the winds will be ushering
in. Winds will gradually diminish by Sunday night...before low
pressure approaches the waters from the southwest early next week.
water levels have dropped in west-northwest flow.
District of Columbia...none.
Maryland...Wind Chill Advisory until 10 am EST Thursday for mdz501.
Winter Weather Advisory until 6 PM EST Thursday for mdz501.
Virginia...Wind Chill Advisory until 10 am EST Thursday for vaz503-504-
Winter Weather Advisory until 6 PM EST Thursday for vaz503.
WV...Wind Chill Advisory until 10 am EST Thursday for wvz501-503-
Winter Weather Advisory until 6 PM EST Thursday for wvz501-503-
Marine...Small Craft Advisory until 6 am EST Friday for anz530>534-
Small Craft Advisory until 8 PM EST Thursday for anz535-536.