Scientific Forecaster Discussion
fxus61 klwx 200129
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
829 PM EST Tue Nov 19 2019
high pressure will build in from the west through Thursday. A
cold front will move across the region Friday afternoon. A low
pressure system will approach the area late Saturday into
Near term /until 6 am Wednesday morning/...
a mid-upper level trough will remain in place overnight, leading
to continued cloud cover. A shortwave disturbance will descend
down the western periphery of the trough tonight, but any
precipitation associated with this feature should remain off to
our south and west. With light west-northwesterly flow in the
925-850 hpa layer, some light upslope precipitation will be
possible along the Allegheny Front. Model soundings indicate
that Max temps in the saturated layer will be around -5c, so it
may be difficult to get ice crystals to form. As a result,
freezing drizzle may be possible on the higher ridges of the
Allegheny Front. Can't completely rule out some light snow
either. Elsewhere, conditions are expected to remain dry with
mostly cloudy skies. Lows overnight will predominantly be in the
30s, with some lower 40s possible over the Metro areas.
Short term /6 am Wednesday morning through Thursday night/...
high pressure centered over the Ohio Valley build eastward into
our region Wednesday. Cloudy conditions are expected in the
morning, with cloud cover gradually decreasing through the day.
High temperatures will be in the 40s and 50s.
High pressure will be centered overhead Wednesday night, then
move to our south on Thursday with a mid to upper level ridge
aloft. Dry conditions and southerly flow are expected on
Thursday. Clouds will build back in from the west through the
day as a cold front approaches. High temperatures Wednesday and
Thursday will be in the 40s and 50s. Lows Wednesday night will
be in the 30s for most areas, and then in the 40s on Thursday
Long term /Friday through Tuesday/...
high pressure will continue to slide offshore allowing a cold front
to enter the region late Friday. While the morning hours
on Friday look to remain mostly dry,especially for the Metro area,
anticipate showers developing by the early afternoon over the
Appalachians with spotty showers persisting throughout the remainder
of the day elsewhere.
Conditions are likely to remain damp overnight into Saturday
as a secondary low develops along the frontal boundary. This will
cause additional rain to spread back into the region throughout the
day Saturday. Precip may end as a brief period of snow over the
Appalachians late Saturday night as the low exits the region. High
pressure builds back into the region on Sunday as conditions look to
remain dry through early next week.
Overall temperatures throughout the forecast period will continue to
Aviation /01z Wednesday through Sunday/...
skies will remain mostly cloudy overnight, but ceilings will be
VFR. Gusty northwesterly winds are expected over the terminals
tomorrow, with up to 20 knot gusts possible. Clouds will be on
the decrease through the day Wednesday, with VFR conditions
expected to persist through Thursday.
Sub-VFR conditions are possible on Friday with a cold front
moving across the area. A brief period of VFR conditions is
possible late Friday into Saturday before periods of sub-VFR
conditions return into Sunday.
sub-Small Craft Advisory level winds are forecast tonight. A Small Craft
Advisory is in effect for Wednesday as winds are expected to
increase. Sub-Small Craft Advisory conditions expected through Thursday night
with high pressure in control.
Sub-Small Craft Advisory conditions are possible Friday with a cold front moving
across the area.
anomalies seem to have turned the corner and are slowly decreasing,
but since winds are light and westerly through tonight, there won't
be dramatic decreases. Therefore have advisories continuing through
the evening high tide cycle, it's possible a few locations could
fall just short (including the warning at straits point). Stronger
northwest winds should do a better job driving out the excess water
on Wednesday, although Straits Point could come close to minor flood
again first thing in the morning.
District of Columbia...coastal flood advisory until 3 am EST Wednesday for dcz001.
Maryland...coastal flood advisory until 5 am EST Wednesday for mdz014.
Coastal flood advisory until midnight EST tonight for mdz016.
Coastal Flood Warning until 11 PM EST this evening for mdz017.
Coastal flood advisory until 2 am EST Wednesday for mdz011-018.
Virginia...coastal flood advisory until midnight EST tonight for vaz057.
Coastal flood advisory until 3 am EST Wednesday for vaz054.
Marine...Small Craft Advisory from 9 am to 6 PM EST Wednesday for