Area Forecast Discussion Issued by NWS Sterling, VA
000
FXUS61 KLWX 060825
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
425 AM EDT Tue Jun 6 2023
.SYNOPSIS...
A weak cold frontal boundary will drop southward across the area
today. Thereafter, high pressure will build toward the area from
the Ohio Valley through the end of the week as low pressure
off the New England coast gradually weakens.
&&
.NEAR TERM /THROUGH TONIGHT/...
Current satellite imagery shows clear skies across the forecast
area, although some high cirrus is evident over western PA, and
will overspread portions of the forecast area over the next few
hours as it descends down in northwesterly flow. Smoke from
Canadian wildfires continues to remain present at mid-upper
levels as well. This will give the sky a milky appearance today,
even in locations that don`t have cloud cover.
A vertically stacked area of low pressure will continue to
circulate in the Gulf of St. Lawrence today. Locally, we`ll
have deep northwesterly flow today. At the surface, a weak cold
front will drop southward out of PA this afternoon, and drop
southward across the forecast area during the late afternoon and
evening. A few showers, or even a brief thunderstorm could form
across northeastern Maryland as the cold front drops south into
the area around peak heating. The environment will be rather
moisture starved, with surface dewpoints only in the 40s, and
additional dry air aloft. This should largely act to suppress
the shower/thunderstorm activity. If any showers or
thunderstorms are able to form, they could produce some gusty
winds, given deep inverted V profiles evident in soundings (with
cloud bases close to 10,000 feet), which would drive
evaporationally driven downdrafts in response to any
precipitation. The environment is so dry, that SPC has actually
introduced a rare isolated dry thunderstorm contour in their
fire weather outlook just to our northeast across PA/NJ.
Temperatures will top out in the low- mid 80s for most this
afternoon, and then drop back into the 50s tonight.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
The upper low situated over the Gulf of St. Lawrence today will
retrograde westward over New England over the next couple days,
as troughing digs a bit further south into the Mid-Atlantic.
Predominantly dry conditions are expected over that time period,
with just a slight chance for a shower from central Virginia to
southern Maryland tomorrow, and then a slight chance for an
afternoon thunderstorm to the east of I-95 Thursday afternoon.
Temperatures will be slightly below normal, with highs in the
mid 70s to near 80 for most. Dewpoints will remain very unseasonably
low, with upper 30s to mid 40s expected on Wednesday and Thursday.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
Upper trough over the Northeast will maintain a cooler than normal
pattern Friday into Saturday. One disturbance is fcst to rotate
through the area and may bring a few showers across the area Fri
afternoon. The trough axis will lift out late Fri with ridging
building in Fri night into Sunday leading to a warmer trend. Another
trough/closed low aloft developing over the Midwest on Sunday may
bring a better chance of showers/t-storms early next week.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
VFR conditions are expected at all terminals through Thursday.
There could be some slight visibility reductions due to smoke
tonight into the day Wednesday, but conditions are expected to
remain VFR. Winds will be out of the northwest through Thursday,
and could gust to around 20 knots this afternoon.
Isold showers possible Friday.
&&
.MARINE...
Winds are currently light out of the west across the waters.
Winds are expected to pick up a bit in northwesterly flow
during the daytime today. SCAs are in effect this afternoon for
the northern portions of the Bay, as well as the middle and
upper Tidal Potomac. A few showers or even a brief thunderstorm
may be possible this afternoon across northern portions of the
Bay as a weak cold front drops southward over the waters.
Coverage of these showers and thunderstorms looks to be low, to
potentially non-existent, but if they do occur, SMWs may be
needed. Lighter north to northwesterly flow is expected over the
waters on both Wednesday and Thursday.
Except for possible isold showers Fri afternoon, weather looks
fairly benign through the weekend. Unsettled weather returns early
next week.
&&
.FIRE WEATHER...
Relative humidity values are expected to drop into the mid 20s
to near 30 percent at peak heating this afternoon. This will
overlap with northwesterly winds of around 10 to 15 mph, with
gusts to around 20-25 mph. Greenup has already occurred, and
vegetation is living, but conditions have also been very dry
lately. There`s also a very low, but non-zero chance for dry
thunderstorms this afternoon across northeastern Maryland. SPC
has a rare isolated dry thunderstorm contour just to our
northeast across PA/NJ.
&&
.TIDES/COASTAL FLOODING...
Anomalies have fallen to between half of a foot and a foot.
Minor flooding is still anticipated with the higher of the two
tides this morning at Annapolis and Straits Point, where Coastal
Flood Advisories are in effect. DC will also come very close to
reaching Minor Flood Stage this morning. Northwesterly winds are
expected to bring down anomalies further during the day today.
Continued northwesterly winds over the next few days should help
keep anomalies down. More sensitive sites may reach Action stage
on Wednesday and Thursday, but no flooding is anticipated after
high tide this morning.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Coastal Flood Advisory until 11 AM EDT this morning for MDZ014.
Coastal Flood Advisory until 6 AM EDT early this morning for
MDZ017.
VA...None.
WV...None.
MARINE...Small Craft Advisory from noon today to 7 PM EDT this evening
for ANZ530>532-535-536-538>540.
&&
$$
SYNOPSIS...KJP
NEAR TERM...KJP
SHORT TERM...KJP
LONG TERM...LFR
AVIATION...LFR/KJP
MARINE...LFR/KJP
FIRE WEATHER...KJP
TIDES/COASTAL FLOODING...KJP