Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 171943

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
243 PM EST Fri Feb 17 2017

A warm front will cross through the area this afternoon. A weak
system then passes nearby Saturday night into Sunday morning. A
backdoor cold front will be near the region Monday into Tuesday,
followed by another disturbance Tuesday night into Wednesday.


A warm front is crossing through the area this afternoon with
temperatures still in the 40s as of 2PM northeast of the DC
Metro to around 60F across central VA and parts of West
Virginia. This will continue pushing northeastward through the
remainder of the day. Mid-cloud deck from earlier today has
dissipated with only some high clouds streaming overhead.

For tonight, aside from scattered high clouds, we`ll be looking
at mostly clear skies. Air mass above the surface will be
warming rapidly overnight, but with mainly clear skies and light
winds, radiational cooling should still allow surface/2-meter
temperatures to fall into the 30s.


Significantly warmer weather is expected for the weekend. Mostly
sunny skies for the first half of Saturday will give way to
increasing clouds in the afternoon ahead of a weakening
disturbance moving into the southeastern US. Temperatures will
soar to 20-25 degrees above normal, with highs well into the
60s to even some low 70s southward towards Charlottesville and

The disturbance will pass south of the region Saturday night.
There may be some light rain showers overnight as the system
passes nearby, but any precipitation will be very light. Lows
generally in the 40s.

Dry weather and mostly sunny skies return for Sunday with
another day of highs in the 60s to around 70F. A system will
pass through New England Sunday night, and while not directly
affecting our region, it may set up a backdoor cold front that
will be near the area for Monday. Lows Sunday night around 40F.


Main concern in the long term to start out is the growing potential
for a northeasterly flow behind a backdoor cold front Monday and
Tuesday, and potentially Wednesday as well. This will be due to a
high pressure centered over southeastern Canada allowing cooler
maritime air to surge south and west around the bottom of the high
into our region. While no precipitation is expected Monday and
Tuesday thanks to ridging aloft, low clouds are possible, especially
Tuesday, and temperatures will be cooler than what otherwise might
be expected given warm air present aloft and a ridge overhead.

Wednesday a weakening cold front is expected to move in from the
west. Some showers are possible but significant precipitation is not
anticipated, so our very dry February will continue with little
improvement. As this front moves through, the wedge of cooler air
may be displaced briefly, but may return quickly as high pressure
returns to its favorable location for wedging - southeastern Canada.
Otherwise, late week looks dry.


VFR conditions expected to prevail through Saturday as high pressure
remains in control of the weather. Weak disturbance moves near
the area Saturday night into Sunday morning...with a chance for
light showers. Light rainfall rates should keep flight
restrictions rather marginal/brief...with perhaps a brief period
of sub-VFR (best chance at KCHO). VFR returns after daybreak

Sub-VFR will be possible early next week, especially BWI/MTN, as a
back door cold front could bring some low clouds into the region.
Best chance of this is Tuesday. A little drizzle is even possible
though significant rain is not expected through Tuesday. A few
showers are expected on Wednesday as a weak front passes with
continued chance for sub-VFR. Winds through the period look mostly
below 20 knots.


Relatively light and sub-SCA winds expected through
Sunday night...with the typical increases/decreases during the
day/night due to diurnal mixing trends.

Backdoor cold front may bring a risk of marginal SCA conditions
Monday and Tuesday with another cold front bringing the same
small risk on Wednesday. Winds may briefly reach 20 knots in
gusts Monday through Wednesday, but should not get stronger than




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