516
FXUS61 KLWX 211833
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
233 PM EDT Sun Jun 21 2026
.WHAT HAS CHANGED...
There is potential for two rounds of thunderstorms during Monday
afternoon and evening, with the first most likely to produce
severe weather. This raises confidence that there could be a few
instances of urban and poor drainage flooding.
&&
.KEY MESSAGES...
- 1) Strong to severe thunderstorms along with locally heavy
rainfall possible on Monday.
- 2) After a mid week dry spell, daily thunderstorm
chances will return for the end of the week.
&&
.DISCUSSION...
KEY MESSAGE 1...Strong to severe thunderstorms along with
locally heavy rainfall possible on Monday.
A low pressure system is forecast to track from the Ohio River
Valley northeast on Monday with the associated warm front lifting
north across the region throughout the day. This will bring the next
chance of severe weather to the region, with the Storm Prediction
Center having most of the forecast area in a slight risk for
severe weather. There still remains a good bit of uncertainty
regarding timing and severity of storms, given the model
guidance discrepancy in the track of the low pressure system and
associated fronts. With southerly flow, a warm and moist
airmass is expected leading to adequate instability.
Additionally, a low level jet is expected to pivot over the
forecast area leading to 40-50 knots of bulk shear. The
combination of instability and shear leads to a risk of
organized supercells with damaging wind gusts as the primary
threat. Depending on the position of the warm front in the
afternoon, there is an increased risk of isolated tornadoes for
most of the forecast area, but in particular wherever the warm
front sets up.
While storm motion is expected to be progressive, PWATS nearing
and/or exceeding 2 inches will lead to locally heavy rainfall within
the strongest storms. In addition, many models are showing the
potential for two rounds of thunderstorms in the afternoon and
evening. The Weather Prediction Center as most of the area in a
Slight Risk for excessive rainfall with scattered instances of
flooding possible.
KEY MESSAGE 2...After a mid week dry spell, daily thunderstorm
chances will return for the end of the week.
There is still some uncertainty where the cold front will be Tuesday
and whether there are any linger showers or perhaps a thunderstorm
as the mid level trough axis moves through. These chances are
slightly higher for the southern half of the CWA, but many locations
could remain dry. Temperatures will dip back slightly below seasonal
averages into the upper 70s to mid 80s.
High pressure will move across the area Wednesday, resulting in the
most pleasant day of the week. Temperatures will be near or slightly
normal with relatively low dew points in the 50s and mostly sunny
skies.
A slow moving upper level trough/closed low and broad surface low
pressure will slowly lift through the Great Lakes Thursday and
Friday. While temperatures may not rise appreciably, there will
be a return to muggier dew points. Specific forcing may be
nebulous on Thursday especially, but locations west of the Blue
Ridge will have greater instability and be closer to the upper
trough, so these locations may have the highest chance of
thunderstorms. The thunderstorm threat will encompass the entire
area Friday as the surface cold front drops closer to the area.
Some shear will be present, but instability may be limited, so
the severe weather threat is uncertain at this time (supported
by low ML guidance probs).
Forecast uncertainty increases for next weekend as the frontal zone
will behave like a typical weak summer front that may not entirely
clear the area and only have minimal airmass differences across it.
Saturday could be relatively drier as high pressure moves into the
Great Lakes. However, the stalled front and potential for
ripples in the quasi-zonal flow aloft could bring a chance of
showers and thunderstorms each day in a warm and humid airmass.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR conditions are expected today and through the overnight as dry
conditions continue. Showers and thunderstorms are expected Monday
afternoon and evening with flight restrictions likely. Outside of
storms, southerly winds could gust to 25 kt assuming a warm front
clears the area to the north.
There may be some lingering showers Tuesday depending on how quickly
the cold front moves through. Northwest winds may gust to 20 kt
Tuesday. Wednesday will likely be dry. Thunderstorms are possible
again on Thursday (especially CHO and MRB) and Friday
(areawide).
&&
.MARINE...
Light winds are expected today and through the overnight. Winds
shift to southerly on Monday with a Small Craft Advisory in effect
from 9AM to 6PM. Advisories will likely be needed on Tuesday as
northwest winds gust 15 to 20 knots. Additionally, showers and
thunderstorms are expected across the waters Monday afternoon and
evening with SMWs likely needed.
Northwest winds behind a cold front may result in marginal advisory
conditions on Tuesday. Light winds are expected Wednesday under high
pressure. Small Craft Advisories may be needed Thursday afternoon
into Thursday night in southerly flow. The next upper level
disturbance could bring more thunderstorms Thursday and Friday
afternoon and evening.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from noon to 6 PM EDT Monday for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory from noon to 6 PM EDT Monday for ANZ530-
535>538-542.
Small Craft Advisory from 9 AM to 6 PM EDT Monday for
ANZ531>534-539>541-543.
&&
$$
DISCUSSION...ADS/AVS
AVIATION...ADS/AVS
MARINE...ADS/AVS
NWS LWX Office Area Forecast Discussion