Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 191831
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
231 PM EDT Tue Sep 19 2017

.SYNOPSIS...
A ridge of high pressure will remain over the eastern United
States through early next week. Meanwhile, Hurricane Jose is
expected to track north off the Mid Atlantic coast through
Wednesday. Refer to the National Hurricane Center`s website
hurricanes.gov for the latest on Jose.

&&

.NEAR TERM /THROUGH TONIGHT/...
A ridge of high pressure will remain overhead through tonight
while surface high over northern New England wedges down into
the Mid-Atlantic. Jose will continue to move northward...passing
us by well offshore.

Low clouds have given way to some sunshine...resulting in
another warm afternoon. Max temps are expected to be in the
lower to middle 80s across most locations. However...moisture
from Jose will bring more clouds and perhaps even an isolated
shower to locations along the western shore of the Bay. Highs
in the mid to upper 70s are expected for these areas.

Jose will continue to move off t the northeast tonight while
high pressure builds overhead. More mild conditions are expected
with min temps ranging from the 50s n the Potomac Highlands to
the mid and upper 60s in downtown Washington and Baltimore.
Areas of fog are expected overnight...especially across central
Virginia and for valley locations west of the Blue Ridge
Mountains. This is where the flow will light and the atmosphere
is most likely to decouple. Farther east...fog is less likely
because of a sustained light northwest flow behind Jose.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
An upper-level ridge will remain over the area...but a weak
disturbance will approach from the west. A northwest flow behind
Jose will allow for sunshine and it will be unseasonably warm
for this time of year due to subsidence associated with the
upper-level ridge. Max temps will be in the mid to upper 80s
across most locations. A few popup showers are possible later
Wednesday afternoon and evening across the Potomac Highlands
into central Virginia where there will be a little instability
closer to the weak upper- level disturbance. However...coverage
will be isolated to widely scattered due to the lack of a strong
lifting mechanism.

High pressure both at the surface and aloft will continue to
build overhead Wednesday night through Thursday night. Dry warm
conditions are expected during this time. Areas of fog are
likely during the overnight and morning hours.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Mainly dry conditions expected in the long term period as upper
level ridge/surface high pressure continues over our area Friday
into Tuesday. Some showers over the ridges cannot be ruled out,
but looking dry over most of our CWA. High temperatures will be
in the mid 80s, around 10 degrees higher than normal. Remnants
of Jose might be lingering off of the Mid- Atlantic/New England
coast, away from us, and Maria could be somewhere in the west
Atlantic, but it is too early to tell. Check out the National
Hurricane Center`s website: hurricanes.gov, for additional
information in both Jose and Maria.

&&

.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
VFR conditions are expected this afternoon through this evening.
Areas of fog are expected overnight into Wednesday morning. The
best chance for fog will be in the western terminals where the
flow is lighter. IFR vsbys are possible in KMRB and KCHO.

High pressure will remain over the terminals for later Wednesday
through Thursday night. Areas of fog are possible during the
overnight and morning hours.

VFR conditions expected Friday into Sunday with high pressure
over our area.

&&

.MARINE...
Jose will continue to move north well offshore this afternoon
before moving away from the area tonight through Wednesday.
Breezy conditions with gusts around 20 to 25 knots have occurred
this afternoon...with the strongest winds over the southern
Maryland Chesapeake Bay and lower Tidal Potomac. These winds
will continue through early this evening before gradually
dissipating. Will continue with the Small Craft Advisory for all
of the waters...but it will be marginal for the upper Tidal
Potomac River and northern Chesapeake Bay. A Small Craft
Advisory remains in effect for tonight across the middle portion
of the Bay and the lower Tidal Potomac River as north to
northwest winds channel.

Northwest winds will continue Wednesday. A few gusts around 20
knots cannot be ruled out...but latest forecast has gusts capped
at 15 knots due to a weaker gradient as Jose moves away. High
pressure will build overhead for Wednesday night through
Thursday night.

No small craft advisory expected between Friday and Sunday due
to low wind speeds over our area.

&&

.TIDES/COASTAL FLOODING...
A Coastal Flood Advisory remains in effect for Straits Point in
St. Marys county through tonight. Elsewhere...a northwest wind
may keep water levels below minor flood thresholds but
confidence is low because of a build up of water near the mouth
of the Chesapeake Bay. This water will try to come back north up
the Bay during the next high tide cycle tonight or
Wednesday/Thursday. Am leaning toward the surge coming up later
Wednesday into Thursday when the northwest flow eases.
Therefore...minor tidal flooding is possible during the high
tide cycle later Wednesday into Thursday morning. Moderate
flooding cannot be ruled out at Straits Point during this time.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Coastal Flood Advisory until 6 AM EDT Wednesday for MDZ017.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ530-
     531-535-536-538-539-542.
     Small Craft Advisory until 6 AM EDT Wednesday for ANZ532>534-
     537-540-541-543.

&&

$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...BJL
LONG TERM...IMR
AVIATION...BJL/IMR
MARINE...BJL/IMR
TIDES/COASTAL FLOODING...BJL



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