474
FXUS61 KLWX 291858
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
258 PM EDT Wed May 29 2024

.SYNOPSIS...
A cold front will move through the area tonight with high pressure
building in from the northwest behind the front. High pressure
remains overhead throughout the weekend before pushing east at the
start of the workweek.

&&

.NEAR TERM /THROUGH TONIGHT/...
A cold front is currently pushing through the forecast area,
bringing showers and thunderstorms to much of the area. A line
of thunderstorms is currently stretching from Frederick Maryland
down to Charlottesville Virginia, with wind gusts 30-40mph being
observed with this line. These thunderstorms will continue to
track east through the afternoon and into the evening. SPC
mesoanalysis as the line of storms moving into slightly more
favorable conditions compared to what CAMs indicated in the AM
and overnight runs. SBCAPE 500-1000 J/kg and effective shear
25-35 kts remain not overly favorable, but expecting storms to
continue to produce wind gusts and small hail. While PW values
remain below 1 inch, heavy downpours are possible in localized
areas. Storm motions of about 30mph should keep thunderstorms
progressive in nature, minimizing flooding threats.

Shower and thunderstorm activity is expected to diminish this
evening in the wake of the frontal passage. Temperatures tonight
will be in the 50s for most with those at higher elevations
dipping into the 40s.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
The aforementioned upper level trough will continue pivoting and
deepening over the east coast throughout the day on Thursday. A dry
airmass in place will keep any widespread precipitation at bay, but
the disturbance moving overhead will result in some clouds over the
region. In addition to some clouds, a stray rain shower cannot be
ruled out, mainly in the southern portions of the forecast area. The
upper level trough will exit the region overnight Thursday into
Friday morning, with ridging moving in behind it.

At the surface, high pressure will build in from the Great Lakes
beginning Friday as the upper level trough moves off shore. Cloud
cover will decrease Thursday night into Friday with sunny skies and
dry conditions expected during the day. Dry air aloft will have
dewpoints in the 30s to 40s, yielding seasonably cool temperatures.

There will be a temperature gradient on both Thursday with highs in
the low 60s for those at higher elevations while those in the
southern potions of the forecast area and in the metros are in the
upper 70s. Temperatures moderate slightly on Friday with
temperatures ranging from mid 60s to mid 70s across the area
dependent on elevation. Clear skies and light winds will provide
favorable conditions for radiational cooling each night. Overnight
lows on Thursday will dip into the 40s along and west of the Blue
Ridge with those east of the Blue Ridge staying in the 50s. Some
locations along the Alleghenies could even drop into the 30s with a
potential for some frost. Overnight lows on Friday will be just a
few degrees warmer with temps in the 40s-50s.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Quiet weather conditions look to continue into the first half of the
weekend with low pressure over eastern Canada drifting east and high
pressure overhead. Overall flow will remain fairly zonal throughout
the weekend which will allow for a slow return of low level moisture
and shortwave disturbances heading into early next week.

Saturday, will be the pick of the weekend with high pressure nearly
overhead. Mostly sunny skies are expected with high temperatures in
the upper 70s and low 80s. High pressure will slowly push off the
southeast U.S coast Saturday night into Sunday allowing for an
uptick humidity and cloud cover. Skies will turn mostly clear to
partly cloudy with lows in the upper 40s and low to mid 50s.

By Sunday, high pressure centers itself off the southeast U.S coast.
This will lead to a return of low level moisture in form of
increased humidity as well as the risk for a few thunderstorms along
and west of the Blue Ridge as shortwave energy pushes east from the
Midwest region. Better chances for showers and thunderstorms exists
during the afternoon and evening hours Monday and Tuesday areawide as
additional pieces of shortwave energy pivot through. Rainfall
amounts are expected to be light at this point and no severe weather
is anticipated at this point.Neither SPC nor WPC have highlighted
any threats over the region for the period at this time. Even with
that said, CSU Learning Machine Probabilities and CIPS analogues
continue to point toward stronger storms during the Tuesday and
Wednesday time. This is in association with a cold front that will
slowly progress eastward by the middle and latter half of next week.
We will continue to monitor this threat over the next several days.

Temperatures will creep back above normal Monday through Wednesday
next week. Highs will warm back into the mid to upper 80s and
perhaps low 90s with 850 mb temperatures running +12 to +16 degrees
Overnight lows will return to the mid to upper 50s and low 60s.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
VFR conditions are expected at all terminals through Friday. The
exception will be this afternoon and into the evening with
showers and thunderstorms expected to impact all terminals. As
of 2:15PM, a line of thunderstorms is bringing gusty winds and
sub-VFR conditions to KIAD, KMRB, and KCHO. This line is
expected to progress east, impacting KDCA, KBWI, and KMTN by
20Z. Shower and thunderstorms will dwindle this evening after
00Z with VFR conditions returning areawide overnight.

VFR conditions are expected Saturday and Sunday with high pressure
nearby. A slight chance for a few thunderstorms is possible mainly
at terminals along and west of a line from KMRB down to KCHO. Some
restrictions are possible in and around any thunderstorm activity
that may form. Higher chances for more widespread restrictions from
shower and thunderstorm activity are possible Monday through
Wednesday as multiple pieces of shortwave energy push through.


&&

.MARINE...
Westerly winds this afternoon will remain below SCA criteria.
SMWs are currently in effect with additional SMWs likely as
showers and thunderstorms impact the waters this afternoon and
into the early evening. A cold front will cross over the waters
later tonight, with winds shifting to out of the northwest
behind the front. Northwesterly winds remain below SCA criteria
tonight and Thursday, but may near SCA criteria periodically.
North/northwesterly flow will remain below SCA criteria on
Friday, with dry conditions expected across all waters.

Sub-SCA level winds are expected Saturday and Sunday. Winds will be
calm to variable Saturday with high pressure overhead. South to
southeasterly winds return Sunday as high pressure pushes off the
southeast U.S coast. An isolated shower or thunderstorm cannot be
ruled out due to the bay breeze Sunday afternoon/evening. Better
chances for showers and thunderstorms exists Monday through
Wednesday as multiple disturbances pass through.


&&

.TIDES/COASTAL FLOODING...
Offshore flow will continue through Thursday. This will lead to
lower water levels. No tidal flooding is expected through
Thursday, but Annapolis and DC may potentially reach Action
Stage around high tide.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.

&&

$$

SYNOPSIS...AVS
NEAR TERM...AVS
SHORT TERM...AVS
LONG TERM...EST
AVIATION...AVS/EST
MARINE...AVS/EST
TIDES/COASTAL FLOODING...KJP