354
FXUS61 KLWX 060145
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
945 PM EDT Wed Jun 5 2024

.SYNOPSIS...
Unsettled weather today through Thursday as a series of fronts
cross the region. Mostly dry conditions on Friday in the wake of
the cold front. A slow moving upper trough approaches the area
from the Great Lakes this weekend leading to more unsettled
conditions.

&&

.NEAR TERM /UNTIL 7 AM THURSDAY MORNING/...
A tropical air mass with low LCLs and ample low-level shear has
certainly been the supercell producer over the area. While
initially producing weaker circulations, NWS and terminal
doppler radars showed a pronounced uptick in circulation
strength and duration. A few cyclic supercells have produced
tornadoes across a number of counties east of the Potomac River
in Maryland. Given the extreme degree of shear shown on the 00Z
KIAD RAOB, the ongoing action seems to support this
environment.

The current radar imagery shows a broad area of slow moving
convection across much of northeastern Maryland. A mix of
Tornado Warnings and Flash Flood Warnings continue over portions
of this area of the state. This should gradually exit in the
next couple of hours. In the wake, some light rain showers will
push from southwest to northeast across the area. Do not expect
any severe or flood threat with any of this activity.

For tonight, the combination of saturated grounds and a
warm/humid air mass will support low clouds with some patchy
dense fog. Low temperatures remain very warm, generally in the
70s for most, with mid 60s west of I-81.

&&

.SHORT TERM /7 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
The leading mid-level shortwave moves east of the area Thursday
morning, as a weak cold front continues its slow trek through the
area. This boundary is likely to produce a broken line of showers
and thunderstorms during the late morning to afternoon, mostly along
and east of the Blue Ridge. Additional showers could develop in the
Alleghenies. Very warm afternoon temperatures in the low to mid 80s,
with some spots possibly reaching the upper 80s.

Not much cooling in wake of the front for Thursday night as lows
settle in the upper 50s to mid 60s. High pressure starts to build in
from the west Friday as westerly winds around 5-10 mph continue.
Aside from a few showers in the Alleghenies, mostly dry conditions
are forecast Friday. Afternoon highs will be closer to normal, in
the upper 70s to low 80s. Seasonal lows Friday night in the 50s,
with low 60s along the immediate Western Shore and Potomac River.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Upper level troughing will remain over the Mid-Atlantic throughout
the long term period. There still remains a good bit of model
discrepancies with regards to when and where a cutoff low develops
within the upper level troughing. Guidance also varies on how far
south the low will go, but general consensus is having the low track
towards SE Canada and the northeast US throughout the weekend and
into early next week. With upper level troughing overhead, diurnal
precipitation chances, albeit low (<40% PoPs) are possible each day.
Saturday looks to be the driest with precipitation chances being
confined to the northwestern portions of the forecast area. The best
chances for precipitation will be Sunday into Monday as a cold front
and associated low pressure system move through the area.

Temperatures each day will be in the 70s to low 80s with higher
elevations staying in the 60s. Overnight lows will be in the 50s for
most locations. However, those along and east of I-95 and in metro
areas may stay in the low 60s.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
A cluster of severe thunderstorms continue to move northeastward
across Harford and Cecil counties. Any severe weather threat has
left the local terminals. There will be some VCTS at KMTN
through around 02-03Z.

Given the moist air mass in place, would expect some lingering
showers into the overnight. Low clouds are likely to build in
again at BWI and MTN tonight, and could reach as far west as
MRB, IAD, and DCA though confidence is low at this time. Best
confidence in IFR CIGs tonight is at BWI and MTN.

A cold front will push through on Thursday, bringing yet another
round of showers and thunderstorms to the TAF sites. MRB should
be just showers during the morning hours before instability is
able to build. However, the rest of the TAF sites could see
thunderstorms during the early-mid afternoon.

High pressure builds into the region Thursday night into Friday,
bringing dry conditions and continued west winds.

Westerly winds blowing 5 to 10 knots on Saturday become light and
variable overnight. Winds pick up slightly on Sunday, gusting 15-20
knots while blowing out of the northwest. Prevailing VFR conditions
are expected this weekend with sub-VFR conditions possible during
afternoon showers and thunderstorms on Sunday.

&&

.MARINE...
Special Marine Warnings persist over the far northern waters,
which is accompanied by a risk of waterspouts given the highly
sheared low-level environment. Any severe threat will end in the
next couple of hours.

Increasing southerly winds tonight into Thursday morning will likely
result in SCA conditions in the open waters of the Chesapeake
Bay, along with the Lower Tidal Potomac.

Winds turn out of the southwest Thursday morning ahead of the
approaching cold front. As the cold front pushes through late
morning into the afternoon, thunderstorms may develop once
again, with some SMWs potentially needed.

Winds will then turn out of the west Thursday afternoon in the
wake of this cold front. At this time, winds are forecast to
remain below SCA level.

Westerly winds around 5-10 knots Friday, with dry conditions.

Westerly winds on Saturday may briefly gust 15-20 knots in the
afternoon, especially in the northern portions of the Chesapeake
Bay. Winds diminish overnight before shifting to northwesterly on
Sunday, gusting 15-20 knots during the afternoon. SCAs are possible
Sunday afternoon in the northern portions of the Tidal Potomac and
Chesapeake Bay.

&&

.TIDES/COASTAL FLOODING...
With a steady southerly flow in place across the region, tidal
anomalies have been on the increase today. This paired with the
approaching new moon have brought several sites to minor flood
stage in the past couple of high tide cycles. This will continue
through the Thursday morning high tide cycle, where Annapolis
could even approach Moderate flood stage. A cold front crosses
the area early Thursday, with the resulting west winds causing
tidal anomalies to drop by Thursday evening/night.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Flood Watch until 10 PM EDT this evening for MDZ011.
VA...None.
WV...None.
MARINE...Small Craft Advisory until noon EDT Thursday for ANZ530>533-
     537>541.
     Small Craft Advisory until 2 PM EDT Thursday for ANZ534-543.

&&

$$

SYNOPSIS...CJL
NEAR TERM...BRO/CJL/KRR
SHORT TERM...CJL/KRR
LONG TERM...AVS/CJL
AVIATION...AVS/BRO/CJL
MARINE...AVS/BRO/CJL
TIDES/COASTAL FLOODING...CJL