Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 231500
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1100 AM EDT Fri Sep 23 2016

.SYNOPSIS...
High pressure is crossing the region today as a cold front
approaches from the north. The cold front will cross the area
Saturday. High pressure returns to the region Sunday before moving
off the coast Monday. A cold front will slowly pass through
Tuesday into Wednesday. High pressure will return for late next
week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Mostly sunny and very warm to hot day in store for the region. Dry
northwest flow aloft will be in place, and only clouds will be some
high cirrus drifting overhead and a few afternoon cumulus. Highs
well into the 80s to around 90F.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
Cold front will approach from the north late tonight and pass
through the region Saturday morning. For the most part, this will be
a dry frontal passage with only an increase in clouds, although a
few isolated showers are possible across the terrain on Saturday.
Lows tonight in the low to mid 60s for most. Highs Saturday in the
70s to low 80s.

High pressure will nose into the area behind the front Saturday
night with generally clearing and drying conditions. Exception will
be across the terrain in western areas where northeasterly flow
behind the front may produce some low stratus and possibly an
isolated shower or two in some light upslope flow. Lows Saturday
night in the 50s to low 60s.

High pressure will settle across the Northeastern US for Sunday and
Sunday night, keeping the area mostly dry, but promote the
development of onshore easterly flow. At the same time, will see
warming aloft beginning Sunday night. Sunday likely to be partly-
mostly sunny for central/eastern areas, with more clouds west along
the terrain. Clouds then increase Sunday night, and onshore flow may
lead to the development of some low clouds, patchy fog, and some
drizzle, especially west towards the terrain. Highs Sunday in the
70s with lows Sunday night in the 50s to around 60F.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
A cold front will approach the area Monday before slowly passing
through Tuesday into Wednesday. A southerly flow ahead of the
front along with isentropic lift will likely bring plenty of
clouds along with a few showers Monday into Monday night.

Exact timing of the frontal passage is uncertain...with some
guidance bringing it through early Tuesday and other guidance
holding off on the frontal passage until Wednesday. This will have
a significant impact on the forecast during this time. Will allow
for the chance of showers Tuesday and Wednesday...but confidence
is low.

High pressure will build in behind the boundary late next
week...bringing dry and seasonable conditions.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR area-wide today with a few cirrus and fair weather cumulus
through the day. Winds variable, turning generally westerly this
afternoon, but light, mainly 5-7 knots.

A cold front will cross Saturday morning with a shift to northerly
winds and an increase in clouds, although likely remaining mainly
VFR. Primarily VFR conditions continue into Sunday, with the
possibility for the development of some sub-VFR conditions Sunday
night in low stratus, mainly CHO/MRB.

A cold front will approach the terminals Monday. Subvfr cigs along
with a few showers are possible Monday into Tuesday. Subvfr cigs
may persist through Tuesday depending on the timing of the frontal
passage. Uncertainty with timing of the frontal passage remains
high at this time.

&&

.MARINE...
Sub-SCA conditions expected today with mainly sea-breeze flow, less
than 15 knots. Cold front crosses late tonight and Saturday morning,
with a surge of wind gusts up to about 20 knots. Thus, a Small Craft
Advisory has been issued from 2 am to 2 pm on Saturday. Winds taper
off Saturday afternoon. An additional wind surge is possible
Saturday night into Sunday morning with near-SCA conditions once
again. Sub-SCA conditions then return by Sunday afternoon and Sunday
night.

A cold front will approach the waters Monday through Monday night.
A southerly flow may gust past SCA criteria late Monday through
Monday night. The cold front will slowly pass through Tuesday into
Wednesday. Timing of the frontal passage remains uncertain so
Small Craft conditions are possible during this time. High
pressure will approach for late next week.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies remain around one-half foot above normal. Minor
flooding is not expected during the next high tide cycle this
morning into this afternoon. The next high tide late this
afternoon into tonight will be the higher of the two astronomical
norms. Water levels will likely be closer to minor flooding
levels...but with the lack of an onshore flow the latest forecast
keeps levels below minor flooding thresholds.

&&

.CLIMATE...
Unusually warm weather has persisted over the area for
quite some time. Autumn-like temperatures will finally make an
appearance over the weekend likely bringing low temperatures at
DCA below 60 degrees for the first time since June 9th, or 105
days ago. The record most consecutive days at or above 60 degrees
in the Washington DC area is 112 set in 2012.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 2 AM to 2 PM EDT Saturday for
     ANZ530>534-537>543.

&&

$$
SYNOPSIS...BJL/RCM
NEAR TERM...MM
SHORT TERM...MM
LONG TERM...BJL
AVIATION...BJL/MM/RCM
MARINE...BJL/MM
TIDES/COASTAL FLOODING...BJL
CLIMATE...DFH/BJL



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