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fxus61 klwx 190801 

Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
401 am EDT Thu Sep 19 2019

high pressure will remain in place over the region through this
weekend. A cold front will slowly move into our region during
the early part of next week as the high slides to our southeast.


Near term /through tonight/...
high pressure will move overhead today and tonight. Plenty of
sunshine, dry conditions and a light northeast wind is expected.
High temperatures will top out in the lower to middle 70s. Low
temperatures will bottom out in the middle 50s. Good radiational
cooling is expected again tonight; thus, leaving an open
invitation for some patchy fog to form in our region. Most, if
any, fog that forms would be mainly in the lower valleys.


Short term /Friday through Saturday night/...
the area of high pressure will slide southward into the Tidewater of
Virginia and the eastern Carolinas Friday through Saturday night.
Dry conditions and plenty of sunshine is still expected across our
region. Friday's high temperatures will be about 5 to 7 degrees
warmer than Thursday as light and variable winds favor more of a
south to southwesterly wind to usher in warmth and some higher
humidity. Saturday's high temperatures will be about 5 degrees
warmer than Friday as the southwest breeze continues. Low
temperatures, both Friday night and Saturday night, will favor a
similar trend of the next night being milder than the previous night
as lows dip into the middle to upper 50s Friday night, then the
middle 60s Saturday night. Lows in our western zones, including the
Potomac Highlands could encounter lower to middle 40s Friday


Long term /Sunday through Wednesday/...
by Sunday, the ridge axis will begin to push offshore as a trough
axis crosses the center of the Continental U.S.. temperatures at 850 mb rise by
a degree c or two, suggesting the highs may make a run at 90
degrees. Humidity will increase slightly too, but not to oppressive

As the trough axis pushes toward the East Coast Monday, it will drag
a surface front along. Forcing still does not look all that
impressive, and timing of the frontal passage unfavorable. Will
stick with a chance shower type wording. Quantitative precipitation forecast likely will be meager.
Suspect Monday will be a touch cooler, due more to a greater amount
of cloud cover (although there will still be partial sunshine).

In the wake of the front, Tuesday and Wednesday do look slightly
cooler, but still above normal for late September. A broad
surface/low level ridge will return, but with zonal flow aloft.


Aviation /08z Thursday through Monday/...
upslope MVFR ceilings developing along the Blue Ridge at this
time, affecting cho/mrb. These should continue through sunrise.
Otherwise, VFR conditions expected through Saturday night for
all terminals. If patchy fog forms at either cho or mrb tonight
or one of the weekend nights, then it could reduce conditions
briefly to IFR with visibility.

VFR conditions should prevail Sunday and Monday, although some
predawn valley fog possible. Clouds will increase during Monday,
with scattered showers at night. Subsequent vsby restrictions


no marine hazards expected through Saturday night. Winds northeast
becoming east 10 knots today, then southeast 5 to 10 knots tonight.
Winds generally southwest 5 to 10 knots Friday through Saturday

Pattern may be conducive for south channeling Sunday night, although
it would be premature to dive into details of a mesoscale phenomenon
at this juncture. Otherwise the pressure gradient should be light
enough to preclude any flags Sunday or Monday.


Tides/coastal flooding...
over the next two to three high tide cycles, tides will be promoting
minor coastal flooding up and down the lower Potomac and much of the
Chesapeake Bay. Minor coastal flooding resulting in advisories have
been extended. There is also a chance of minor coastal flooding
in one or two of these location Friday morning, but a little
too early to tell.


Lwx watches/warnings/advisories...
District of Columbia...coastal flood advisory until 3 PM EDT this afternoon for
Maryland...coastal flood advisory until 10 PM EDT this evening for
Coastal flood advisory until midnight EDT tonight for mdz014.
Virginia...coastal flood advisory until 10 PM EDT this evening for vaz057.
Coastal flood advisory until 3 PM EDT this afternoon for
Marine...Small Craft Advisory until 8 am EDT this morning for


near term...klw
short term...klw

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