Area Forecast Discussion
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FXUS61 KLWX 180906 AAB
Area Forecast Discussion...UPDATED
National Weather Service Baltimore MD/Washington DC
406 AM EST Wed Jan 18 2017
A cold front will pass through the area this morning. High
pressure will build toward the region today before settling
overhead Thursday. A warm front will move into the area Friday
and it will stall out nearby through Saturday. Low pressure will
affect the area to start the new week.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Warm front from yesterday has stalled overnight across the
region, and have seen widespread dense fog develop on the cool
side of the boundary, from about the DC metro on northward. At the
same time, a cold front will continue pushing eastward across the
area through the early morning hours. As it crosses, will see a
wind shift to the northwest and a general drying trend as cool/dry
air advection ensues. This should cause the fog to erode and
Small/compact upper level low will then cross the region during
the late morning/early afternoon hours. This combined with some
lingering moisture and developing northwesterly flow will lead to
a strato-cu deck of clouds, especially northeastern areas, with
clearing developing by the afternoon for central VA. May also be a
few isolated showers across Maryland as the upper low spins
across. The northwest flow will also help to touch off upslope
rain/snow showers, although with warm boundary layer conditions,
any snow accumulations will be negligible. Peak wind gusts to the
20-30 mph range.
Highs today quite mild, from 50-60F.
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
High pressure then builds in for tonight and Thursday with dry and
mild conditions expected. Lows tonight in the 30s, with highs
Thursday into the 50s again.
Low pressure system will then push northeastward out of the
Mississippi Valley and into the Lower Great Lakes Thursday into
Thursday night before weakening on Friday. This will send an area
of rain towards the Mid Atlantic states for Friday along the
weakening warm frontal boundary. Current indications are that the
highest chances of rain will fall in the 15z-21z (10am-4pm) time
period for the DC Metro area. Rain will then taper off by the
evening with clouds and possible areas of fog persisting Friday
High temperatures Friday will range from the mid 40s north/east to
low 50s south/west. Lows Friday night around 40F.
.LONG TERM /SATURDAY THROUGH TUESDAY/...
A weak boundary will remain overhead for Saturday...but ridging
overhead behind a departing disturbance should allow for dry
conditions across most areas. Temperatures will continue to be
above normal for this time of year.
A potent jetmax in the southern stream of the jet will track into
the Gulf Coast States Saturday night...forming a cutoff low. The
low will track northeast into the Tennessee Valley and Mid-
Atlantic Sunday before passing through our area Monday. Details
with timing are uncertain this far out...but it does look like a
soaking rain is likely Sunday into Monday. The low will slowly
pull away from the area during the middle portion of next week.
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
Widespread reductions early this morning in fog and low stratus
will improve to VFR for most TAF sites by around 12z as a cold
front crosses the region. Will see a strato-cumulus deck of clouds
with bases from about 3000-5000 feet agl persist through the day,
and this may cause occasional periods of MVFR, mainly at MRB.
Otherwise, gusty northwest winds will develop with gusts up to
about 25 knots.
VFR will continue with winds slackening tonight and Thursday.
Sub-VFR conditions then expected to develop again on Friday with
period of rain and lowering ceilings as a warm front crosses the
region. Low clouds and areas of fog may persist Friday night.
Low clouds are likely for Saturday through Sunday. Areas of fog
are possible Saturday morning. Rain chances will increase
Saturday night into Sunday as low pressure approaches from the
south. IFR/SubIFR conditions are most likely during this time.
Southerly winds will turn northwesterly as cold front crosses the
region early this morning with gusts 20-25 knots expected today.
Therefore, SCA is in effect through 6 PM. Winds will slacken
tonight, however some gusts near SCA are still possible across the
central Chesapeake Bay.
Sub-SCA winds then expected Thursday through at least Friday
A weak boundary will remain near the water Saturday. Low pressure
will approach the waters Saturday night through Sunday before
passing through Monday. A Small Craft Advisory will likely be
needed for the waters during this time.
MARINE...Small Craft Advisory until 6 PM EST this evening for
Small Craft Advisory until 6 PM EST this evening for ANZ533-