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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 101431
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1031 AM EDT Fri Sep 10 2021

.SYNOPSIS...
An upper level trough axis will push to our east today as high
pressure over the Mississippi River Valley migrates eastward.
The high will settle overhead tonight into the first half of
Saturday before shifting to the south and east for the
remainder of the weekend and into early next week. A frontal
boundary may approach the area from the north toward the middle
portion of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Mid-morning update: Previous forecast remains on track. Previous
discussion follows...

Sprawling high pressure is centered from the Upper Midwest
southward across the Mississippi River Valley to the northern
Gulf Coast states. A frontal boundary resides off the Mid
Atlantic coast, and it will continue its eastward progression
away from coast today as the primary upper level trough lifts
into the Northeast.

For today, the aforementioned high will build eastward, settling
overhead by this evening. With the reinforcing cold front
offshore and the tightening gradient as the high builds
eastward, breezy northwest winds are expected today, gusting
20-25 mph at times, up to 30 mph across the ridges. A cold air
advection regime will yield high temperatures generally in the
mid to upper 70s, 60s in the mountains, with a mix of clouds and
sun by this afternoon.

As the high settles overhead this evening and overnight, winds
will slacken and skies will clear. Prime radiational cooling
conditions will emerge as a result, allowing temperatures to
cool off into the 40s across the higher elevations, with 50s
everywhere else.
-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
High pressure will remain atop the region Saturday morning,
before centering itself to our southeast by Saturday evening.
This will allow for winds to turn more southerly, albeit light,
with continued dry conditions and abundant sunshine. Highs will
be a touch warmer compared to today as a result, reaching into
the upper 70s to lower 80s, upper 60s to low 70s across the
Allegheny and Potomac Highlands. Lows Saturday night drop back
into the 50s to middle 60s.

The high will remain positioned across the Southeast and the western
Atlantic Sunday and Sunday night, with continued dry conditions
and mostly clear skies. Southerly breezes will increase Sunday
as warm advection improves as well. This will allow for
temperatures to warm to above normal levels for this time of
year, with highs in the mid to upper 80s, perhaps a few 90
degree readings for those typical warmer locations. In the
higher elevations, 70s to near 80 degrees will be more typical.
In addition to the warmer temperatures, dewpoints will lift back
into the low to middle 60s, bringing summer like conditions to
the region. Dry conditions and near normal temperatures expected
Sunday night as the upper pattern turns more zonal.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Ridge axis will be overhead during the first half of the week, then
slide offshore as an upper level trough over the western Great Lks
pushes east. Well above normal temperatures are expected during this
time. Precip chances improve somewhat during the second half of the
week as heights fall with approach of Great Lks trough. However,
with main frontal zone expected to remain north of the region,
convection will be scattered at best.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
High pressure will build into the region today, settling over
the terminals tonight through the first half of Saturday before
positioning itself to the south and east for the remainder of
the weekend. As a result, northwest winds today will gust to
around 20 knots before the high moves in. Winds will trend light
and variable tonight before turning southerly Saturday and
remaining as such through Sunday night, generally at 10 knots or
less. Under the influence of the high, VFR and dry conditions
are expected through the weekend.

No sig wx expected Mon through Wed.

&&

.MARINE...
High pressure over the Mississippi River Valley will drift
eastward today, tightening the gradient in the wake of the
frontal passage yesterday. As a result, northwesterly SCA gusts
are expected much of the day before relaxing late this
afternoon and evening as the high settles over the region. High
pressure will position itself to our south and east Saturday and
remain so through the remainder of the weekend. As a result,
light southerly breezes will emerge Saturday afternoon and
remain as such through Sunday night. Could be a period of
southerly channeling SCA gusts Saturday night and again Sunday
night for the wider Chesapeake Bay waters.

SCA conditions are possible Tue night into Thu in srly
channeling.

&&

.TIDES/COASTAL FLOODING...
Strengthening southerly winds Sat night could result in minor
coastal flooding at Annapolis Sat night into Sunday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for
     ANZ530>543.
-- End Changed Discussion --

&&

$$
SYNOPSIS...BKF
NEAR TERM...BKF/KJP
SHORT TERM...BKF
LONG TERM...LFR
AVIATION...BKF/LFR
MARINE...BKF/LFR
TIDES/COASTAL FLOODING...LFR