Area Forecast Discussion Issued by NWS Sterling, VA
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000
FXUS61 KLWX 081425
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1025 AM EDT Thu Jun 8 2023
.SYNOPSIS...
An upper low will continue to circulate to our north through
Friday, before progressing offshore on Saturday. An area of low
pressure will approach the area from the Great Lakes early next
week.
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.NEAR TERM /THROUGH TONIGHT/...
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1030 AM Update: Thick smoke has continued to build into portions
of the area this morning, with updates in Air Quality Alerts for
the District of Columbia as the AQI`s continue to increase
(>325 in localized areas). A few showers and thunderstorms have
developed across the far SE areas of our northern VA counties
and into southern MD. These storms should be remain below severe
criteria, while bringing some gusty winds of 15-20 knots
intermittently over the next couple of hours before dissipating.
Smoke should improve heading into the afternoon hours from
north to south but is expected to at least linger into Friday.
Previous Discussion Follows:
An upper low will continue to circulate to our north across
Upstate NY/New England today. Meanwhile, a shortwave disturbance
will rotate through the base of the upper low`s circulation,
tracking across the southern half of Virginia this morning into
the early afternoon hours. In response, surface convergence is
expected to be on the increase from the Fredericksburg area to
southern Maryland this morning. Around 500-1000 J/kg of CAPE is
expected to build across southern Maryland this morning in
response to daytime heating. A few showers are already present
in this area (as of 3 AM), but further development of showers
and thunderstorms is expected late this morning into very early
this afternoon. These showers and storms should progress off to
the east by mid- late afternoon as the aforementioned shortwave
passes off to our east. Elsewhere, dry conditions are expected
today. Temperatures will run a bit below normal, with mid to
upper 70s common (upper 60s in the mountains).
The other main story today will be the continued presence of
wildfire smoke. A plume of very thick smoke is descending down
from the north in northerly flow this morning. Visibilities have
dropped to 1.5-3 miles across northern Maryland. This thick
smoke is expected to continue to progress southward over the
next several hours. Gradual improvement may occur during the
afternoon hours as winds turn northwesterly and deeper mixing
ensues. Yet another plume of smoke may descend down into the
area tonight. Please refer to airnow.gov or local environmental
agencies for the latest air quality information.-- End Changed Discussion --
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.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
The aforementioned upper low will continue to circulate to our
north through the day tomorrow. Another disturbance rotating
through the southern periphery of the circulation will sharpen
up and progress through the area tomorrow. This will lead to the
development of showers, and potentially even a few thunderstorms
across the entire area tomorrow afternoon. Smoke may once again
be present across the area, and temperatures will continue to
run below normal, with highs in the low to mid 70s for most (60s
in the mountains).
The upper low that has been situated to our north for several
days now will finally start to progress off toward the east on
Saturday. This will lead to height rises aloft, and mostly sunny
skies. Temperatures will run a bit closer to normal, with highs
in the upper 70s and low 80s for most.
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.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Shortwave ridging will build over the region Sunday ahead of next
closed upper low forming over the western Great Lks early next week.
Associated to this closed upper low, a low pressure center and
associated cold front will bring widespread showers and
thunderstorms late Sunday night through Monday night before cdfnt
exits the area early Tue. Overall, guidance has trended wetter and
more unstable for Monday, but risk for flooding rains and severe wx
still remains low. A brief dry window appears likely Tue behind
frontal passage, but upper low passing north of the region Tue night
will bring renewed chance of showers and thunderstorms Tue
afternoon
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.AVIATION /14Z THURSDAY THROUGH MONDAY/...
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A plume of thicker smoke is descending down in northerly flow
early this morning. Visibility went VIFR at BWI earlier this
morning but has sense improved to MVFR. Other terminals will
continue to linger around 1 to 1 1/2SM through the morning
hours. CHO may even reach IFR later this morning, but have kept
them MVFR for now. Gradual improvement is expected through the
afternoon hours, with most sites returning back to VFR as winds
turn northwesterly, and deeper mixing commences once again.
Recent model guidance hints that another plume of smoke may
descend down into the area tonight. As a result, visibilities in
most TAFs have been dropped to MVFR during that time. Smoke may
linger through much of Friday as well, albeit likely not as
thick as what is currently ongoing. Outside of smoke, the next
potential weather impact to the terminals will be showers, and a
few thunderstorms Friday afternoon. Winds will be out of the
north this morning, and then northwest this afternoon through
Saturday.
Dry Sunday. Widespread showers and thunderstorms Monday with flight
restrictions likely at time.-- End Changed Discussion --
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.MARINE...
Prevailing sub-SCA level winds are expected over the waters
through Saturday. Winds will generally be out of the northwest,
but may be out of the south for a short time later this
afternoon into this evening for the middle Bay and lower tidal
Potomac. Smoke will cause reduced visibility over the waters
through at least Friday. A few showers and storms may move over
the wider waters of the lower tidal Potomac and middle Bay late
this morning into early this afternoon. Special Marine Warnings
may be needed for any of the stronger storms.
SCA conditions are likely Saturday night into Monday night. T-storms
are likely on Monday.
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.TIDES/COASTAL FLOODING...
Sensitive tide locations will reach Action Stage during the
highest diurnal tide over the next couple of days. Tidal
anomalies should remain low, and no flooding is currently
forecast. However, sensitive locations like Annapolis and DC SW
Waterfront will be close.
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.LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.-- End Changed Discussion --
&&
$$
SYNOPSIS...KJP
NEAR TERM...ADS/KJP/ADM
SHORT TERM...KJP
LONG TERM...LFR
AVIATION...LFR/KJP/ADM
MARINE...LFR/KJP
TIDES/COASTAL FLOODING...KJP