Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 152257

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
657 PM EDT Sun Oct 15 2017

A cold front will push into the Mid Atlantic tonight followed
by a return to high pressure early in the week and hold through
the end of the week.



The band of incoming precipitation has been thin and is located
across NW PA to western WV. While low-level convergence and 850
mb thermal forcing good, these features outrun the upper level
support. As a result, mesoscale guidance depict a rapid
weakening as soon as the line hits the Appalachians. Regardless,
the best chance will come in the overnight hours... Blue
Ridge/Catoctins west at or before midnight, east of there
overnight. Chance PoPs for most places, but there could be local
enhancement as the line approaches southern Maryland early
Monday morning.


The front will be clearing the area Monday morning. Based on
current extent and speed, there could be some lingering showers
east of I-95 early. Otherwise, the day will be marked by clearing
skies and increasing winds due to a surge of cold advection.
Gusts to 20-25 mph seem likely. Temperatures may not be purely
diurnal, but advection and compression may balance out during
the afternoon.

High pressure build over the area Monday night through Tuesday
night. If winds decouple quick enough early Tuesday morning,
frost would be possible as radiational cooling conditions should
be otherwise nearly ideal. Have added it to the HWO. Tuesday
night into Wednesday morning would also have that potential.


Dry weather conditions are expected in the long term period as
surface high pressure is centered near or over our area between
Wednesday and Sunday. At the upper levels, ridge will be
amplifying and building over our region Thursday night and
remain into Sunday. High temperatures will above normal, and
will be gradually increasing from the 60s and low 70s on
Wednesday to upper 70s/near 80 on Sunday.



A cold front will cross the terminals tonight. Precipitation
should be scattered and brief. Restrictions unlikely. The wind
shift will be the most notable item, within a few hours of
midnight. A period of VFR clouds (cigs 040-050) will also

Northwest winds will gust to 20-25 kt on Monday. Winds will
diminish Monday afternoon-evening. Otherwise VFR through



Likely will have a lull this evening as a cold front approaches
the area. But, after frontal passage, which will be pre-dawn, a
surge of northwest winds will have good momentum transfer
potential. Will keep a Small Craft Advisory for all waters
through Monday, and then end in a staggered fashion during
Monday night.

Winds will be lighter for the rest of the week as high pressure
crests overhead.


MARINE...Small Craft Advisory until 2 AM EDT Tuesday for ANZ531>533-
     Small Craft Advisory until 6 PM EDT Monday for ANZ530-535-536-
     Small Craft Advisory until 6 AM EDT Tuesday for ANZ534-537-543.


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