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fxus61 klwx 191813 
afdlwx

Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
213 PM EDT Thu Oct 19 2017

Synopsis...
high pressure will remain across the mid Atlantic through this
weekend. A low pressure system will affect the region early
next week.

&&

Near term /through tonight/...
an elongated area of high pressure stretches from the deep
south northeastward across the southern Appalachians and off
the mid-Atlantic coastline. At the same time, a weak cold front
is tracking through the Great Lakes region. For the rest of
today, expecting mostly sunny skies, light winds, and mild
temperatures. Highs will range from 70-75f.

The weak front will push east-southeastward this evening, with
its tail end crossing the region tonight. Aside from a shift to
light northwest winds and a few added cirrus, no real sensible
weather impacts are expected with this decaying front. Although
as winds do turn to the northwest, there may be some terrain-
induced strato-cumulus along the Allegheny Front by morning.
Should still have decent radiational cooling tonight, but with
some added light winds, won't be as ideal as previous nights.
Lows in the 40s to near 50f for most, except low/mid 50s in the
urban centers and along the shorelines of the Chesapeake and
tidal Potomac.

&&

Short term /Friday through Saturday night/...
high pressure will gradually build back overhead for Friday and
Saturday, providing for mostly sunny skies, relatively light
winds, and mild temperatures. There may be some patchy fog each
late night/morning, but nothing widespread expected. Highs will
reach the low to mid 70s, with lows in the 40s/50s.

&&

Long term /Sunday through Wednesday/...
high pressure system will move away from the East Coast on
Sunday. A cold front approaches from the west with a wave of low
pressure tracking northeast from the Gulf states towards the
mid-Atlantic region Monday into Tuesday. This system will put an
end to the dry spell we've been experiencing, with
precipitation associated with it starting sometime on Monday
and remaining into Tuesday.

The pattern will evolve from warm and dry to cold and unsettled
as this system moves through, with some uncertainty on the
timing. In the upper levels, a large and deep trough will move
over the eastern Continental U.S. Wednesday into Thursday. Guidance
suggests that this could bring some upslope showers on
Wednesday, and then dry into Thursday.

High temperatures on Monday will be between the low to mid 70s
decreasing into the 60s into Thursday.

&&

Aviation /18z Thursday through Tuesday/...
patchy fog possible at mrb/cho/iad over the next few mornings,
but chances are low and any fog would be brief. Otherwise, VFR
through Sunday night with relatively light winds under high
pressure.

Precipitation associated with a cold frontal system is then
expected later Monday into Tuesday, which could bring sub-VFR
conditions at times.

&&

Marine...
a weak cold front will approach and cross the waters tonight.
Expecting an increase in southwest winds out ahead of the front,
followed by a surge of northwest winds behind the front. While a
surface inversion will limit mixing and wind gust potential
along the shores, over the open warmer waters, gusts in excess
of 20 knots are possible, especially late tonight into Friday
morning. Therefore will leave Small Craft Advisory in effect
from 9 PM tonight through noon Friday. Winds will drop below Small Craft Advisory
criteria by Friday afternoon and remain below through Sunday.

Southerly winds will increase out ahead of the next frontal
system Monday and Tuesday, and a Small Craft Advisory may be
needed.

&&

Lwx watches/warnings/advisories...
District of Columbia...none.
Maryland...none.
Virginia...none.
WV...none.
Marine...Small Craft Advisory from 9 PM this evening to noon EDT Friday
for anz531>534-537-539>541-543.

&&

$$
Synopsis...mm

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