Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 160221
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
921 PM EST Wed Nov 15 2017

.SYNOPSIS...
A cold front will cross much of the region overnight, and then
move east of the Chesapeake Bay Thursday morning. High pressure
will build over the area Friday, followed by a strong cold front
which will cross the region Saturday night. High pressure will
return by early next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
At 02Z, rainfall associated ahead of the cold front made it
across the Appalachains, producing scattered showers measuring a
few hundredths of an inch. Expecting the scattered showers to
continue to move east overnight, but decreasing in areal
coverage and intensity, particularly east of the Blue Ridge. By
the time the feature gets to the western shore of the
Chesapeake, it should be only very light scattered showers. Min
temps should be in the upper 30s west of I-95, and lower 40s
closer to the bay. Winds will remain light less than 10 mph,
generally from the south/southeast.

By daybreak Thursday, clouds will be breaking up, with any
isolated showers east of I-95 having pushed towards Delmarva,
and then the front will pass, causing a gusty northwest wind
from mid-morning through evening timeframe, with mostly sunny
skies.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
Cdfnt will exit east of the Chesapeake tomorrow morning, with
shifting winds and becoming windy after 15Z with gusts possibly
up to 45 mph in the mtn ridges and up to 35 mph in the east. May
need a wind advzy over the mtns. It will be a little warmer
with highs in the upper 50s to lower 60s due to strong downslope
flow. Thu night it will still be breezy due to tight pres
gradient. High pressure builds over the area Fri with
diminishing winds.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A cold front will cross the region late Saturday. Euro/GFS/NAM all
showing very little instability as it comes thru. Still some showers
expected with the frontal passage in our area. Breezy ahead of the
front and then gusty winds with the cold advection Sat night into
Sunday. GFS has the strongest winds just behind the cold front late
Sat night. Models have winds in the mixed layer behind the front in
the 30s of kts, while the GFS is in the 40s of kts. If it ends up
being closer to the GFS, wind advisories would be needed. But model
uncertainty is high in that regard at the moment.

Near to below normal temperatures for early to mid next week. Gusty
cool high pressure moving in on Sunday with snow showers on our
western fringe in the Appalachians. Euro still is weaker with this
with less snow...an inch or so. GFS is still more bullish. Leaning
towards the Euro since the high builds in fairly quickly for Mon and
Tue. Another cold front is expected at the end of the period for mid
week.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
MVFR is holding steady with CIGS at KDCA & KCHO. Expecting this
to break up overnight, with an alto deck moving through with
the scattered showers, remaining until shortly before daybreak.

Winds shift to the NW after 12Z Thu with fropa with gusts up to
around 30kt.

Winds will switch from SW to NW late Sat and will be rather gusty
with some gusts of 45kt possible just after the front. A period of
MVFR or even IFR conditions possible Sat afternoon into Sat night.
VFR for Sunday and Monday with high pressure.

&&

.MARINE...
Winds light and variable through the overnight, then
strengthening toward dawn. Cdfnt crosses the area just after 12Z
Thu with winds shifting to NW and gusting up to 30 kt through
Thu night. Winds begin to diminish Fri, but increase again Sat
ahead of next cdfnt.

SCA conditions are likely Saturday and Sunday, with even a period of
gale force winds possible after the cold front Sat night
into Sunday day.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 4 AM Thursday to 6 AM EST Friday for
     ANZ530>534-537-539>541-543.
     Small Craft Advisory from 10 AM Thursday to 6 AM EST Friday
     for ANZ535-536-538-542.

&&

$$
SYNOPSIS...Lee/LFR
NEAR TERM...Lee/LFR
SHORT TERM...LFR
LONG TERM...CAS/LFR
AVIATION...CAS/LFR
MARINE...CAS/LFR



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