282
FXUS61 KLWX 052132
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
532 PM EDT Sun Jul 5 2026
.WHAT HAS CHANGED...
Expanded the Flood Watch into the Washington DC metro and north
central Maryland. Thunderstorm outflows from north central
Virginia and the Appalachians (convection which is developing
ahead of an upper air ripple) could congeal in this area, which
is already showing convergence with building cumulus and a few
radar echoes. 18Z CAMs and the experimental WoFS all show
localized QPF maxima in this general area, with localized totals
of 2 to 4 inches of rain possible.
&&
.KEY MESSAGES...
- 1) A risk of a few severe thunderstorms and spotty flash
flooding exists through Monday.
- 2) Seasonable temperatures return mid to late week
despite continued chances for showers and thunderstorms.
&&
.DISCUSSION...
KEY MESSAGE 1...A risk of a few severe thunderstorms and spotty
flash flooding exists through Monday.
An active weather pattern continues with the latest convective
and hydrologic outlooks highlighting risk areas over the Mid-
Atlantic. Starting with today, the Storm Prediction Center (SPC)
has placed all areas east of the Alleghenies within a Slight
Risk, with a Marginal Risk for this mountain range. Looking at
the flash flooding potential, all areas north of I-64 are
currently in a Slight Risk. For those with outdoor plans,
ensure to keep an eye on the sky and have multiple ways to
receive National Weather Service alerts.
With the longstanding mid/upper ridge having buckled on the
northern end, an array of impulses (including an MCV approaching
from OH) are able to work their way across the hot and humid
air mass. While convection is likely to initiate across the
terrain first, other mesoscale features will need close
attention as well. Most notably, these would include river and
bay breezes, but also a multitude of outflows laid out by
previous convection. Moisture- laden downdrafts will have access
to a very deep and well mixed boundary layer through this
evening. As downdraft CAPE values range from 800 to 1,200 J/kg,
these should support ample wet downburst potential. Instability
may be slow to fully be exhausted so convection likely festers
into the overnight hours as well.
On the hydrologic side, multiple rounds of storms are expected
which will increase the risk of flash flooding. While the best
high-resolution signal for heavier rainfall is just north of the
Mason-Dixon Line, this could easily seep southward to the I-70
corridor. One area where confidence has increased is central to
northeast MD where approaching storm motion may lay parallel to
the bay breeze this evening. As PWs increase to 2+ inches,
repeated thunderstorms with very heavy rain could result in
flooding especially in urban areas. Convergence on the north
side of a mesolow developing over the northern neck of VA may
further enhance storm development to its north into MD.
For Monday, a slow moving frontal system accompanying the
stagnant upper trough will yield another day of active weather.
The better instability profiles begin to shift south of I-66
where the SPC features a Marginal Risk. Further, the Weather
Prediction Center has a Slight Risk for flash flooding from the
Blue Ridge eastward. Well above average precipitable water
values (1.75 to 2.25 inches) combined with repeated convection
and slow cell motions will aid in such a risk. Of course this
will also be driven by how much rainfall occurs over previous
days. Although the region remains in drought, this may only
limit flash flood potential for so long.
KEY MESSAGE 2...Seasonable temperatures return mid to late week
despite continued chances for showers and thunderstorms.
Temperatures get back to more seasonable levels Tuesday through the
upcoming weekend ahead. This is due largely in part to a cold front
sagging south of the region Tuesday and a secondary front to follow
within zonal flow Friday into the weekend. With a series of fronts
and modest impulses passing through mid-level flow, expect continued
chances for showers and thunderstorms mainly during the afternoon
and evening hours. As for severe weather, the threat is low, but
not zero. CSU, CIPS, NSSL, and Google WxNet AI/ML continue to
hold probabilities around 5 to 15 percent each afternoon and
evening. Something to continue to monitor on subsequent forecast
cycles given the non-descripte upper-level flow pattern.
High temperatures will remain the 80s (70s mountains) through
Wednesday with a warm up back into the low 90s east of the Blue
Ridge late in the week. Overnight lows each night will mainly range
from the 60s into the low 70s.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
Wind fields remain on the weaker side (S becoming E). Introduced
TEMPOs for TS through the evening. Restrictions would likely
accompany any thunderstorms during this period of interest.
There is a signal for storms to persist later into the evening
and night, especially near/northeast of the Potomac. Thus,
additional periods of sub-VFR conditions are certainly possible.
CIGs may lower in the metros as well, with fog possible for
CHO/MRB by early Monday.
Monday presents one more day of more widespread showers and
thunderstorms. This comes with a shift to mainly easterly flow
as a frontal system meanders about the area. Prevailing VFR
conditions are expected Tuesday through the remainder of the
week with winds out of the east/northeast through Wednesday
before turning back to the south and southwest Thursday into the
weekend. Showers and thunderstorms will be possible each
afternoon and evening yielding temporary restrictions.
&&
.MARINE...
While summertime synoptic gradients will limit the need for
Small Craft Advisories most of the time, daily convection and
the associated outflow boundaries should make for hazardous
marine conditions at times. One exception is that a Small
Craft Advisory has been issued around southern Maryland this
evening as flow briefly strengthens around a mesolow over the
northern neck of VA.In particular, the weather looks more active
through Monday night with numerous showers and thunderstorms
expected each afternoon and evening. Thus, Special Marine
Warnings will be needed at times so boaters should certainly
plan for deteriorating conditions. Always have multiple ways to
receive weather alerts while out on the waters.
Thunderstorm chances decrease Tuesday into Wednesday as the front
pushes south of the region. An additional cold front is expected
Friday into the weekend allowing thunderstorm chances to increase
once again. Some SCA level southerly channeling is possible ahead of
the front Thursday into Friday.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Heat Advisory until 8 PM EDT this evening for DCZ001.
Flood Watch until 1 AM EDT Monday for DCZ001.
MD...Heat Advisory until 8 PM EDT this evening for MDZ008-011-013-
014-016>018-504-506-508.
Flood Watch until 1 AM EDT Monday for MDZ004>006-008-011-013-
014-503>508.
VA...Heat Advisory until 8 PM EDT this evening for VAZ037>039-050-
051-053>057-502-527.
Flood Watch until 1 AM EDT Monday for VAZ053-054-506.
WV...None.
MARINE...Heat Advisory until 8 PM EDT this evening for ANZ530.
Flood Watch until 1 AM EDT Monday for ANZ530.
Small Craft Advisory until 11 PM EDT this evening for ANZ533-
534-537-542-543.
&&
$$
DISCUSSION...BRO/DHOF/EST
AVIATION...BRO/DHOF/EST
MARINE...BRO/DHOF/EST
NWS LWX Office Area Forecast Discussion