197
FXUS61 KLWX 031430
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1030 AM EDT Mon Aug 3 2026

.WHAT HAS CHANGED...
With the expectation of decreasing coverage of heavy rainfall,
have shifted wording to mention south of I-66. Any flash
flooding threat likely focuses closer to the I-64 corridor.

&&

.KEY MESSAGES...
- 1) Additional heavy rainfall is possible this afternoon and
  evening, mainly south of I-66.

- 2) Additional shower and thunderstorm chances persist through
  this weekend.

&&

.DISCUSSION...
KEY MESSAGE...Additional heavy rainfall is possible this
afternoon and evening, mainly south of I-66.

The earlier upper low across the Ohio Valley has now shifted
just north of Lake Ontario while becoming more elongated in
nature. At the same time, this has pushed the parent frontal
boundary along I-81 where it has generally stalled. The forecast
calls for this frontal system to slowly drop southward in time.
The front is going to be the main focus for another round of
showers and thunderstorms. The main uncertainty is the exact
placement of this boundary, with most high res guidance showing
it south of I-66 where low-level convergence is more focused.
This is where most of the rain chances (50-70 pct) will be for
today, with mostly dry conditions to the north/west.

It is still going to be warm and muggy areawide as highs reach the
mid to upper 80s. Thunderstorms once again are going to be efficient
rain makers with a deep warm cloud layer and PWATs above 2". A few
instances of flash flooding are possible if any heavy thunderstorm
develops and moves slowly over regions of poor drainage. The
frontal boundary completely crosses the area this evening,
ushering in drier conditions for tonight. Slightly lower dew
points allow temps to drop to the 60s for most locations (upper
50s in the mountains).

The boundary attempts to lift north as a warm front Tuesday, but only
makes it to around I-64. This means most of the area remains dry.
Isolated showers and thunderstorms are possible in the afternoon
along and south of a line from Staunton to Fredericksburg. The dry
spell is going to be short lived as the warm front lifts north
across the entire area on Wednesday, bringing the return of an
active weather pattern that persists through the weekend.


KEY MESSAGE 2: Additional shower and thunderstorm chances
persist through this weekend.

Showers and thunderstorms will focus in the afternoon & evening
hours each day. Increasing humidity will allow for PWATs ranging
from the 75th-90th percentile, indicating potentially increased
flooding concerns with any thunderstorms that do materialize. Severe
thunderstorm probabilities continue to indicate the potential for
severe thunderstorms during the Thursday-Sunday timeframe, with
machine learning outputs remaining in the 15%-30% range. Still, that
remains uncertain given the lack of defined synoptic support and
abundant cloud cover over the region that limits instability.

As this synoptic pattern persists, temperatures gradually increase
back to summertime normals, with elevated humidity contributing
towards heat indices that will approach 100F across the metros late
into the week. Looking ahead, deterministic models do show some
signal for this front transitioning offshore towards the start of
next week with drier air moving in from the west, potentially
providing some relief from the humidity. For now, the primary
weather feature remains as humid & rainy, along with increasing
heat.

&&

.AVIATION /13Z MONDAY THROUGH FRIDAY/...
A mix of MVFR to near-IFR CIGs continue to impact some
terminals, but general improvements have been noted during the
past couple of hours.

VFR conditions return this afternoon as a front slowly moves south
across the area. Another round of showers/thunderstorms are likely
this afternoon, except at KMRB that will be north of the
boundary. Dry and VFR conditions tonight through Wednesday
morning. Daily shower and thunderstorm chances return Wednesday
afternoon as that frontal boundary lifts back north across the
area as a warm front.

Sub-VFR conditions will likely continue to be intermittent at
terminals throughout the week as daily shower and thunderstorm
chances persist, particularly in the afternoon & evening timeframes.
South to southwesterly winds flow Wednesday through the end of the
week.

&&

.MARINE...
Southerly channeling this morning is going to produce SCA
conditions, especially the main channel of the southern
Chesapeake Bay. A weak front slowly moves south across the
waters today, though not before another round of showers and
thunderstorms develop this afternoon. Special Marine Warnings
are likely needed again today, especially south of the Bay
Bridge and over the lower Tidal Potomac. Wind gusts in excess of
35 knots are the primary threat to mariners, in addition to
lightning strikes.

The front pushes south of the waters this evening. Dry conditions
and sub-SCA winds expected Tuesday into Wednesday morning. The
stalled boundary lifts back north over the area as a warm front by
Wednesday afternoon. Southerly flow returns, and could approach SCA
levels over the central Chesapeake Bay. Wednesday also brings with
it the return of daily afternoon showers and thunderstorms.

Southerly channeling over the waters are anticipated to produce SCA
conditions Thursday afternoon through Friday. Showers &
thunderstorms remain possible over the waters during this period
(especially in the afternoon/evening hours) due to a stalled front
nearby.

&&

.TIDES/COASTAL FLOODING...
Tidal levels remain elevated this morning, but minor tidal
flooding has begun to subside at Annapolis behind high tide.
Other sensitive locations likely top out at Action Stage. A
brief period of lighter winds is expected Tuesday and that
should prevent minor tidal flooding at all locations. Southerly
flow returns Wednesday through the end of the week, bringing the
possibility of additional periods of coastal flooding.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 11 AM EDT this morning for MDZ008.
     Coastal Flood Advisory until 10 AM EDT this morning for MDZ014.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 11 AM EDT this morning for
     ANZ530>534-537>543.

&&

$$

DISCUSSION...BRO/KRR/SRT
AVIATION...KRR/SRT
MARINE...KRR/SRT
TIDES/COASTAL FLOODING...LWX

NWS LWX Office Area Forecast Discussion