732
FXUS61 KLWX 140112
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
912 PM EDT Mon May 13 2024

.SYNOPSIS...
A slow moving low pressure system approaches from the west tonight,
bringing increasing chances for showers and thunderstorms, and below
normal temperatures. Drier weather returns Thursday before another
storm system brings the threat for showers and storms Friday into
the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Dry and seasonal conditions are expected tonight as high
pressure over the area moves away this evening. Overnight
temperatures drop down to the mid 50s to low 60s tonight. Cloud
cover increases from southwest to northeast tonight as an area
of low pressure approaches from the west. 9PM satellite loop
shows clouds moving across the forecast area with some clearing
in the western portions of the area. Cloud cover will fill in late
tonight with cloudy skies west of I-95 and partly cloudy skies
along and east of I-95 expected by sunrise.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Unsettled weather returns to the area Tuesday and Wednesday as a
broad broad upper trough and surface low slowly track eastward
across the area. Showers should be more scattered in nature,
although there could be a few periods of steadier rain. Instability
appears to be rather limited Tuesday, with the best chance of any
thunderstorms west of the Blue Ridge. If anything, there may be a
better opportunity for some elevated rumbles of thunder Tuesday
night. Wednesday brings greater instability across the southwestern
half of the area, where there may be a better chance for some breaks
of sun.

Rain chances finally decrease Wednesday evening into Wednesday night
as the surface low moves across eastern VA toward the Delmarva and
out to sea. Some showers could linger if the upper low is slower to
depart the area, particularly for those along/east of I-95.

There may be a few opportunities for locally heavier rain: (1) with
southeasterly upslope flow into the central Virginia Blue Ridge on
Tuesday, (2) north of the surface low track Tuesday night, and (3)
within the higher instability airmass Wednesday when flow will be
light under the upper trough. Any risk of flooding appears to be
marginal and dependent on multiple or prolonged periods of heavier
rain. Forecast totals range from 0.50-1.00" north of US-50, and
around 1-2" south toward Central Virginia. The threat for severe
thunderstorms appears to be low through the period.

Widespread cloud cover and rainfall keeps daytime temperatures below
normal through mid week as highs only reach the upper 60s to low
70s. Overnight lows settle in the mid 50s to mid 60s.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Low pressure and the resultant upper level trough will pivot off the
Mid-Atlantic coast Thursday while brief mid-level ridging settles in
from the central Appalachians region. This will allow for a brief
reprieve in shower and thunderstorm activity before things ramp up
again later in the workweek.

Unfortunately the calmer weather conditions will be short-lived with
the next upper level trough and low pressure system set to approach
from the Ohio River Valley/Great Lakes region Friday into Saturday.
With that said, model guidance continues to show subtle
discrepancies in regards to to the timing of this system and
placement of it`s associated surface fronts across the region. Most
of the recent 00z guidance suggests an uptick in shower and
thunderstorm activity Friday afternoon and night as a warm front
lifts through the area. A slow moving cold front will immediately
follow this boundary Saturday into Saturday night bringing with it
additional showers and thunderstorms. Severe weather does not appear
to be a concern at this point although one or two strong
thunderstorms cannot be ruled out if CAPE and shear are maximized.
Localized flooding could be the bigger concern given repetitive
rounds of rain throughout the week and rich moisture flooding in
along the slow moving warm front Friday into Friday night.

Upper level ridging tries to build back into the area Sunday
bringing slightly drier conditions. Another front will follow with
renewed chances for showers and thunderstorms Monday and Tuesday
next week. Temperatures throughout the extended forecast period will
remain at or slightly below normal for the middle of May.

&&

.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
VFR conditions expected tonight as high pressure over the area
exits to the east, and an area of low pressure approaches from
the west. Clouds begin to increase in coverage and lower
overnight, though should remain VFR until around sunrise
Tuesday.


Low MVFR to IFR CIGs quickly build in from the southwest at CHO
early Tuesday morning, and eventually reach the other terminals by
the afternoon. Widespread showers and some thunderstorms are
expected through Tuesday evening, with on-and-off showers continuing
into Tuesday night. The low clouds, some reduced visibility due to
mist and rain continue Wednesday morning as the area of low pressure
moves just south of the area.

Conditions dry out on the backside of the low during the second half
of the day Wednesday, but low clouds and sub-VFR conditions could
continue into Wednesday night.

Southerly winds around 10 knots Tuesday turn southeast then east by
Wednesday morning, northeast Wednesday afternoon, then north
Wednesday night as the low pressure moves away from the area.

Sub-MVFR cigs and vsbys remain possible with any spotty shower or
thunderstorm activity that looks to linger Thursday. Mid-level
ridging should promote drier conditions during the late afternoon
and evening as low pressure pushes further offshore. Sub-VFR
conditions return Friday into Saturday as another upper level trough
and series of fronts traverse the region. Shower and thunderstorm
activity will increase across the terminals especially Friday and
Saturday afternoons. Slightly drier conditions and VFR return Sunday
into Monday next week.

&&

.MARINE...
A Small Craft Advisory is in effect for much of the waters
tonight with winds dropping below criteria around midnight.
Peak gusts between 20-25 knots in the open waters of the bay are
likely with winds blowing out of the south.

Winds diminish late tonight, though gusts between 15-18 knots are
possible through Tuesday morning. South-southeast winds increase
once again Tuesday afternoon and evening, with another SCA likely
needed for that time period. Winds could gust slightly higher to
around 24-28 knots in the open waters of the bay during this time.

An area of low pressure will approach the region from the west late
tonight, bringing widespread showers and some thunderstorms to the
local waters Tuesday into Wednesday. Special Marine Warnings may be
needed for portions of the waters if any strong storm capable of
producing wind gusts of 35 knots develops.

The area of low pressure is forecast to move across eastern VA to
the Delmarva Wednesday morning, and winds are forecast to turn
northeast to north and decrease on the backside of the low. However,
another period of SCA winds is possible Wednesday night as northeast
to north winds increase.

SCA conditions are likely Thursday into Friday as low pressure
pushes offshore and weak high pressure builds in. SCA conditions
will linger into the weekend as a series of fronts traverse the
region. This will be the case Friday with a warm front and Saturday
with a cold front set to cross the waters. Shower and thunderstorm
activity will also increase especially during the afternoon and
evening hours.

&&

.TIDES/COASTAL FLOODING...
South to southeast winds through Tuesday night will keep water
levels elevated in the Chesapeake Bay and Tidal Potomac. Expect
additional minor coastal flooding at high tide over the next
24-36 hours, especially at sensitive locations in Annapolis, Otter
Point, DC Waterfront, and Straits Point.

As an area of low pressure moves east of the area Wednesday,
winds become northeast, then north. This should result in
quickly decreasing water levels and reduced coastal flood
threat.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until midnight EDT tonight for ANZ530-538-
     542.
     Small Craft Advisory until 6 AM EDT Tuesday for ANZ531>534-537-
     539>541-543.

&&

$$

SYNOPSIS...KRR
NEAR TERM...AVS/KRR
SHORT TERM...ADS/KRR
LONG TERM...LFR
AVIATION...LFR/KRR
MARINE...LFR/KRR
TIDES/COASTAL FLOODING...LWX