397
FXUS61 KLWX 251813
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
213 PM EDT Wed Jun 25 2025

.SYNOPSIS...
A ridge of high pressure overhead will bring continued hot
conditions over the next couple of days. As the upper-level
ridge slowly weakens in the coming days, daily chances for
showers and thunderstorms will increase through the end of the
week. A weak frontal boundary will slowly drift southward in
time before stalling nearby on Thursday into Friday. This system
lifts northward into New England this weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Temperatures well into the 90s to near 100 degrees, paired with
higher dew points today when compared to yesterday are yielding
impressive instability across the region, on the order of
2000-3000 J/kg of MLCAPE. Thunderstorms are firing off already
and are a bit more expansive in coverage than originally thought
this morning. However, many things do remain the same in regards
to the thinking this afternoon.

DCAPE values on the order of 1200-1400 J/kg are allowing for
some impressive downbursts in the storms that manage to grow
tall. However, a lot of storms are struggling a bit to get
through mediocre mid-level lapse rates. The Marginal risk for
severe weather remain from the Storm Prediction Center, and that
seems to be holding true for the time being.

Most high-resolution models show activity waning into the
overnight hours given the loss of diabatic heating. In the wake
of these storms, expect another muggy night ahead with temperatures
a smidge lower than current conditions. Forecast low temperatures
will be in the 70s with mid/upper 60s across mountain locales.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
The mentioned west-east oriented frontal zone across southern
sections of the Great Lakes is expected to sag southward in
time. By Thursday, the forecast frontal analysis places this
boundary just north of the Mason-Dixon Line. Consequently, a
better chance for showers and thunderstorms will loom on
Thursday into Friday given the close proximity of this boundary
to the area. Forecast temperatures drop a bit on Thursday, but
do remain seasonably hot as highs top out in the low/mid 90s
(80s across the mountains). Additionally, humidity remains
impressive, with dew points well into the 70s. This will still
yield heat indices that necessitate Heat Advisories for much of
the region, albeit a couple of degrees cooler than today. As has
been mentioned in previous days, it is still going to be hot, no
matter the exact headline that is out, so continue to practice
safety precautions when it comes to dealing with the heat.

Thunderstorm activity will become more widespread on Thursday
afternoon as the aforementioned boundary drops southward. There
should be a particular focus near the boundary dropping toward
I-70 on Thursday. Severe weather is again possible on Thursday
as instability remains high, and there should be a bit more
forcing involved. Shear will be pretty limited overall, but
could be just enough, especially near the boundary, to drive a
more impressive damaging wind threat when compared to today. There
may also be a flash flooding component to some of these storms.
This is because they will likely be slow- moving, and could
either train along the south- moving boundary, or storms could
develop off of outflows and become stationary at times. The main
focus would be closer to the frontal zone where any west-east
oriented storms could train/backbuild, and especially if this
occurs over the metro areas.

Storm chances likely linger into Thursday night as the reservoir
of instability is gradually exhausted. The rain cooled air over
the region should help usher temperatures down to more
seasonable levels for late June. The current forecast package
calls for low temperatures in the upper 60s to low 70s, locally
cooler in the higher terrain.

Uncertainty is fairly high heading into Friday as there are many
unknowns in where this backdoor frontal zone sets up. Often
relocated by convective processes, the current thoughts are this
boundary sits over the region on Friday. This would come with a
sharp north/south temperature gradient along it. While
northeastern Maryland could sit in the mid 70s, places south of
I-66 may be well into the 80s to near 90 degrees. Depending on
where this boundary ends up setting up, an additional risk of
severe thunderstorms and flash flooding would loom. For Friday
night, low temperatures are expected to stay fairly close to
readings from the night before.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Daily showers and thunderstorms can be expected through next Tue as
a very warm and humid air mass persists and weak upper air
disturbances move across the area in nearly zonal flow aloft. A
strong trough and associated cold front are fcst to cross the area
next Tuesday. If the timing coincides with peak heating, a
substantial severe wx threat may evolve for next Tue.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
As the upper ridge slowly weakens, a return to daily shower and
thunderstorm chances returns to the forecast. Gradients do
remain light which will keep prevailing winds mainly at 10 knots
or less. Added some TEMPO groups in this afternoon for most
sites, as the coverage of storms is a little more than
anticipated with earlier forecasts. These taper off into this
evening, giving way to light winds and VFR conditions once
again.

Shower and thunderstorm chances increase into Thursday and
Friday as a frontal zone to the north tracks near the region.
Expect periods of restrictions, particularly during the typical
afternoon/evening periods. This backdoor boundary eventually
moves through the area on Friday which should lead to mainly
easterly flow across the area.

Daily showers and thunderstorms Sat and Sun could lead to brief
restrictions should one pass over the airport terminals. Any
storm this weekend could produce brief strong wind gusts as
well.


&&

.MARINE...
As gradients remain on the weaker side, the chances for any
Small Craft Advisories are minimal through the remainder of the
work week. More notably, the threat for showers and storms
returns to the forecast which will pose a risk to those out on
the waters. Some SMWs may be needed later this afternoon into
this evening.

Coverage is expected to increase into Thursday and Friday as a
frontal system slowly pushes southward across the waterways.
SMWs seem likely on both days, but especially on Thursday.

Possible SCA conditions Sat and again Monday. Daily showers and
thunderstorms Sat and Sun as well, which could necessitate the
issuance of some SMWs.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies will remain slightly elevated through the next
several high tide cycles. This will keep water levels slightly
elevated for the more sensitive tidal sites. At this point, only
Fort McHenry and Annapolis are slated to reach Action stage
during the next couple of astronomical high tides. Expect
northwesterly winds to help gradually lower anomalies over the
next day or so.

&&

.CLIMATE...
Here are some daily high temperature records during the June
25-26, 2025 timeframe:

A `+` sign indicates multiple years currently hold that record.

                 ***WEDNESDAY, JUNE 25TH, 2025***
LOCATION                   RECORD HIGH (YEAR)  RECORD WARM LOW (YEAR)
Washington-National (DCA)     100F (1977)          76F (2010)+
Washington-Dulles (IAD)        97F (1966)          71F (1981)
Baltimore (BWI)                99F (1997)          77F (1949)+
Baltimore Inner Harbor (DMH)  104F (1997)          79F (1998)+
Martinsburg (MRB)              99F (1997)          72F (1949)
Charlottesville (CHO)          99F (1997)          77F (1951)
Annapolis (NAK)                98F (2000)+         78F (1997)+
Hagerstown (HGR)               98F (1952)          75F (1949)

                 ***THURSDAY, JUNE 26TH, 2025***
LOCATION                   RECORD HIGH (YEAR)  RECORD WARM LOW (YEAR)
Washington-National (DCA)     101F (1952)          77F (1952)+
Washington-Dulles (IAD)        99F (2024)          72F (2023)+
Baltimore (BWI)                99F (2024)+         80F (1952)
Baltimore Inner Harbor (DMH)  104F (1998)          83F (1952)
Martinsburg (MRB)             102F (1943)          75F (1949)
Charlottesville (CHO)          99F (1998)          78F (1952)
Annapolis (NAK)                98F (1998)+         81F (1952)
Hagerstown (HGR)               98F (1954)+         75F (1952)

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Heat Advisory until 9 PM EDT this evening for DCZ001.
MD...Heat Advisory until 9 PM EDT this evening for MDZ003>006-008-
     011-013-014-016>018-502>508.
VA...Heat Advisory until 9 PM EDT this evening for VAZ025>031-
     036>040-050-051-053>057-501-502-505-506-526-527.
WV...Heat Advisory until 9 PM EDT this evening for WVZ050>053-055-
     502-504-506.
MARINE...Heat Advisory until 9 PM EDT this evening for ANZ530.

&&

$$

SYNOPSIS...BRO
NEAR TERM...CJL
SHORT TERM...BRO/CJL
LONG TERM...LFR
AVIATION...LFR/BRO/CJL
MARINE...LFR/BRO/CJL
TIDES/COASTAL FLOODING...
CLIMATE...