FXUS61 KLWX 261856

AFDLWX



Area Forecast Discussion

National Weather Service Baltimore MD/Washington DC

256 PM EDT Thu Jun 26 2025



.SYNOPSIS...

A ridge of high pressure overhead will maintain hot conditions 

through this evening. Daily chances for showers and storms will 

increase through the end of the week. A weak frontal boundary 

will slowly drift southward in time before stalling nearby 

through Friday. This system gradually lifts northward away from 

the area this weekend. A stronger cold front may cross the 

region by early next week.



&&



.NEAR TERM /THROUGH TONIGHT/...

Abundant sunshine and substantial moisture recovery has really

increased the instability across the region this afternoon. A

cooler start to the day, and a slightly stronger cap than

yesterday, held convection at bay for a few extra hours this

afternoon compared to yesterday. But now, amidst a very unstable

air mass characterized by around 4000 SBCAPE, CI has begun west

of I-81, and perhaps even starting to see some storms along the

Bay/River breezes further east. Current mesoanalysis shows very

little in the way of wind shear, so storms today will have very

similar characteristics to yesterday and remain shorter-lived

and disorganized. However, the coverage is going to be more,

especially as we head later into the evening. Storms currently

over the Potomac Highlands will start to throw down some outflow

boundaries that will quickly move east throughout the afternoon.

more storms will likely develop east of the Blue Ridge as the

convective temperature is reached, as well as along lingering

surface boundaries from yesterday and Bay/River breezes. In

short, it is going to be a very messy convective mode today.

Concern is building for the potential for damaging wind gusts,

as DCAPE values are creeping up in excess of 1000 J/kg. A very

moist column, leading to 2"+ PWATs, paired with steep low-level 

lapse rates will yield an environment favorable for wet 

microbursts. A Severe Thunderstorm Watch was issued through this

evening for this threat for all areas east of the Allegheny 

Front. 



Additionally, as we head into this evening a slow-moving

backdoor cold front will drop south across northeast MD. As 

this occurs, enhanced frontal lift coupled with perturbations in

the mid/upper atmosphere will continue to fire off additional 

showers and thunderstorms into the evening. Really becoming

concerned that there may be a focused area of heavy

thunderstorms along the I-95 corridor, which could lead to some

flash flooding, especially in urban areas. A Flood Watch was

issued to depict this threat area. 



Most high-resolution models depict activity waning after 

midnight so any severe/flood threat should wane at that point.



Besides the convective threats, continued above average

temperatures and high humidity levels will carry heat indices

into the 102 to 107 degree range. Furthermore, Heat Advisories

extend over a bulk of the area outside the mountains from 11 AM

until 7 PM this evening. Continue to find ways to stay cool in

the heat by taking plenty of breaks from the outdoors, staying 

hydrated, and wearing light clothing. Heading into the overnight

hours, the influence of rain-cooled air should help carry lows

into the upper 60s to low 70s (low/mid 60s in the mountains).



&&



.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...

While the placement of the frontal zone is uncertain and likely

re-positioned by convective-scale processes, this system should

be in the vicinity of the Mid-Atlantic region on Friday. Not

only will this carry an additional risk for showers and

thunderstorms, but also comes with a challenging temperature

forecast. For those in the cool sector to the north, highs in

the mid/upper 70s are likely. Off to the south and perhaps even

west of the Blue Ridge, the warm/moist sector will support 

temperatures well into the 80s to near 90 degrees. The current 

forecast calls for this separation of air masses to be between 

I-70 and I-66. 



There should be a particular focus for convection in the 

vicinity of this frontal zone where lift will be augmented. 

Along and south of this front will yield a severe weather 

component to the storms where instability is maximized.

Additionally, well above average columnal moisture profiles

favor further instances of flooding potential. Right now, there

is the potential for this to occur across the Potomac Highlands,

per the 12z HREF. Considerations for a Flood Watch may be needed

during the overnight forecast, but didn't want to draw attention

away from today's threats for now. Depending on how quickly 

instability is exhausted, some of the convection could fester 

into the overnight hours on Friday.



With mid/upper height changes being somewhat neutral, it 

remains to be seen how much northward progress this boundary 

makes on Saturday. This system could easily linger right near 

the Mason-Dixon Line which would maintain a more unsettled 

pattern during the first half of the weekend. The expectation is

for this boundary to drift northward in time on Saturday which

will help usher highs back into the upper 80s to low 90s.

Further, convection would be driven more heavily by instability

versus along any particular frontal boundaries. But as

mentioned, there is plenty of uncertainty in how this all plays

out. Will see Saturday night's lows be a tad milder than

previous nights with readings in the upper 60s to mid 70s.



&&



.LONG TERM /SUNDAY THROUGH THURSDAY/...

Upper troughiness will maintain/support a surface trof across the 

area while Bermuda high keeps a continued very warm and moist air 

mass supporting daily chances of showers and thunderstorms Sun 

into Monday. A stronger trough is fcst to amplify across the 

Great Lks and Mid-Atlantic Tue pushing a stronger cold front 

through the area Tue afternoon. Timing of the frontal passage 

has slowed down some since yesterday supporting a greater risk 

of severe thunderstorms Tue afternoon. A drier air mass will 

follow behind the front for the middle part of next week and 

Fourth of July.



&&



.AVIATION /19Z THURSDAY THROUGH TUESDAY/...

With convection in the forecast through the remainder of the

work week and into the first half of the weekend, periods of

restrictions are looking likely at times. Otherwise, VFR

conditions should be commonplace outside of these convective

episodes. 



For this afternoon/evening, remain confident enough in thunderstorm

development to have a 3 to 4 hour period of TSRA restrictions 

roughly between 20-00Z. As some of this may linger after dark, 

have maintained the PROB30 groups into subsequent hours as 

inherited by previous shifts. Added a TEMPO group in where we

think the best chance for stronger storms will be, with winds

gusting to 40 knots. As storms develop and approach the airport,

that number could be higher or lower, depending on placement of

storms. This is a favorable pattern for wet microbursts, to

strongest winds will be very localized in nature. 



As a frontal zone drifts southward across the area, winds turn

more easterly in nature on Friday. Eventually this boundary does

return northward as a warm front which would bring a return to

south-southwesterlies at some point on Saturday. And as

mentioned, restrictions are possible given a decent chance for

thunderstorms each afternoon/evening.



VFR conditions at all terminals Sunday through Monday night. At

times of convection, we could see brief MVFR visibility and/or 

ceilings. Winds will be light and variable, except higher gusts 

in strong thunderstorms.



&&



.MARINE...

While gradients remain weak enough to keep the waterways free of

Small Craft Advisories, the threat of convection will make for

hazardous boating conditions at times through at least Saturday.

It is difficult to say which day will be the most active in

terms of thunderstorm development, but the degree of continued

heat and humidity should maintain a daily 30-60 percent chance

of storms each afternoon/evening. As usual, frequent lightning

is possible in any such storm, with the stronger cells likely

requiring Special Marine Warnings.



No marine hazards Sunday through Monday night. If thunderstorms

move out over the waters, then Special Marine Warnings may be 

warranted. Winds light and variable through the period, except 

higher gusts in strong thunderstorms.



&&



.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

Annapolis is slated to reach Action stage during the next 

couple of astronomical high tides.



&&



.CLIMATE...

Here are some daily high temperature records on June 26, 2025:



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



                 ***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 7 PM EDT this evening for DCZ001.

     Flood Watch until midnight EDT tonight for DCZ001.

MD...Heat Advisory until 7 PM EDT this evening for MDZ003>006-008-

     011-013-014-016>018-502>508.

     Flood Watch until midnight EDT tonight for MDZ004>006-008-011-

     013-014-016-503>508.

VA...Heat Advisory until 7 PM EDT this evening for VAZ026>031-

     036>040-050-051-053>057-501-502-505-506-526-527.

     Flood Watch until midnight EDT tonight for VAZ053>057-506-526-

     527.

WV...Heat Advisory until 7 PM EDT this evening for WVZ050>053-055-

     502-504.

MARINE...Heat Advisory until 7 PM EDT this evening for ANZ530.

     Flood Watch until midnight EDT tonight 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...LWX

CLIMATE...LWX

