2025 Severe Weather General Discussion

[WxUSAF]

Upgraded to SLGT for today. MCD says a watch unlikely but some severe gusts possible. I’m ready for some rain. 

[WxUSAF]

1 hour ago, WxUSAF said:

Upgraded to SLGT for today. MCD says a watch unlikely but some severe gusts possible. I’m ready for some rain. 

Radar looks like trash. Looked much healthier around 2-3pm.

[high risk]

Worth noting that even though the rotation was very weak, and no warning occurred (or were needed), those overnight storms were actually supercells.     Pretty tough to do that here during the overnight, except during tropical remnant events.

[Eskimo Joe]

8 hours ago, high risk said:

Worth noting that even though the rotation was very weak, and no warning occurred (or were needed), those overnight storms were actually supercells.     Pretty tough to do that here during the overnight, except during tropical remnant events.

It's almost like there's been pulses of EMLs riding on little shortwaves over the mountains. Quite impressive.

[Eskimo Joe]

Okay, I've seen enough. CAMs look good for tomorrow, and we have a solid front slicing into the heat dome. Tomorrow looks like a legit severe weather episode from DC towards Trenton tomorrow. Likely wet microbursts and isolated, but intense flash flooding.

The only two fail modes I could see are abundant debris clouds from overnight convection to our NW, or somehow a bunch of stuff fires over the I-64 corridor and mucks up the overall mean flow into the line.

Otherwise, I'm in.

[Kmlwx]

24 minutes ago, Eskimo Joe said:

Okay, I've seen enough. CAMs look good for tomorrow, and we have a solid front slicing into the heat dome. Tomorrow looks like a legit severe weather episode from DC towards Trenton tomorrow. Likely wet microbursts and isolated, but intense flash flooding.

The only two fail modes I could see are abundant debris clouds from overnight convection to our NW, or somehow a bunch of stuff fires over the I-64 corridor and mucks up the overall mean flow into the line.

Otherwise, I'm in.

Pigs are flying, folks!!!! Man your battlestations! 

[Eskimo Joe]

D2 MOD flood risk from EZF to PHL.

[WxUSAF]

29 minutes ago, Eskimo Joe said:

D2 MOD flood risk from EZF to PHL.

Our own @wxmvpete wrote the disco. It’s intense.

[high risk]

3 hours ago, Eskimo Joe said:

Okay, I've seen enough. CAMs look good for tomorrow, and we have a solid front slicing into the heat dome. Tomorrow looks like a legit severe weather episode from DC towards Trenton tomorrow. Likely wet microbursts and isolated, but intense flash flooding.

The only two fail modes I could see are abundant debris clouds from overnight convection to our NW, or somehow a bunch of stuff fires over the I-64 corridor and mucks up the overall mean flow into the line.

Otherwise, I'm in.

I do think that we could go to SLGT for severe, as there is a fair amount of downdraft CAPE in the forecast soundings.  I think that’s contingent on the initial batch of Precip being an organized southeast-moving line  If there are scattered cells earlier in the afternoon, as shown by a few solutions, our severe chances are likely lower.  But as discussed above, the flooding threat tomorrow is real. 

[Eskimo Joe]

28 minutes ago, high risk said:

I do think that we could go to SLGT for severe, as there is a fair amount of downdraft CAPE in the forecast soundings.  I think that’s contingent on the initial batch of Precip being an organized southeast-moving line  If there are scattered cells earlier in the afternoon, as shown by a few solutions, our severe chances are likely lower.  But as discussed above, the flooding threat tomorrow is real. 

I think an ENH for wind is justified.

[yoda]

1 hour ago, Eskimo Joe said:

I think an ENH for wind is justified.

Who are you?

[high risk]

Interesting that some of the evening CAM guidance initiates convection in the area MUCH earlier than previous runs.   This would probably wipe out most of the SVR threat, but it could lead to multiple rounds of storms that enhance the flooding threat.

[high risk]

5 hours ago, Eskimo Joe said:

I think an ENH for wind is justified.

  with 2" PW values?     That's pretty tough to do.       

Our path to a SLGT is yesterday's 12Z HRRR or NAM Nest, with a semi-organized line arriving just after peak heating.   The majority of the solutions this evening, which break out convection way early and not very organized, would likely only justify a MRGL for a few wet microburst events early in the event before it becomes a heavy rain situation.

[yoda]

SLGT risk up... 0/5/15

Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0100 AM CDT Thu Jul 31 2025

   Valid 311200Z - 011200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
   THE MID ATLANTIC AND THE CENTRAL HIGH PLAINS...

   ...SUMMARY...
   A few strong storms, capable of mainly damaging winds, are possible
   across the Mid-Atlantic and Arkansas during the afternoon. Severe
   wind and hail producing storms are also expected across the northern
   Rockies into the central High Plains.

   ...Synopsis...
   An upper trough will traverse the Northeast while an upper ridge
   persists over the Central U.S. and broad upper troughing becomes
   established over the Interior West today. A surface low will develop
   across the Mid-Atlantic this afternoon with the passage of an
   embedded mid-level impulse within the broader trough, which will
   encourage widespread strong thunderstorm development. Across
   portions of Arkansas and immediate adjacent areas, a weak impulse
   will support the development of at least scattered strong
   thunderstorms amid ample buoyancy. Across the northern Rockies into
   the northern and central High Plains, an embedded mid-level impulse
   will result in the initiation of several thunderstorm clusters,
   which will move over the higher terrain during the afternoon. Given
   adequate buoyancy and shear in these regions, strong to severe
   storms are possible.

   ...Mid Atlantic...
   Thunderstorms should develop during the afternoon, as surface
   temperatures warm well into the 80s F, and quickly translate
   eastward given 40+ kts of 500 mb westerly flow. Surface dewpoints
   will reach well into the 70s F, supporting 2000-3000 J/kg MLCAPE
   despite mediocre mid-level lapse rates. The strong instability and
   30-40 kts of effective bulk shear will encourage the development of
   strong multicells and perhaps a transient supercell. Damaging gusts
   are the main threat, though an instance or two of hail are possible,
   mainly during the afternoon and early evening hours.

[mappy]

9 hours ago, high risk said:

Interesting that some of the evening CAM guidance initiates convection in the area MUCH earlier than previous runs.   This would probably wipe out most of the SVR threat, but it could lead to multiple rounds of storms that enhance the flooding threat.

I noticed that on the morning news futurecast. Last evening’s weather hit showed storms after 4-5pm. This morning had them around 1-2pm. 

[yoda]

Hmmm

https://www.spc.noaa.gov/products/md/md1852.html

 

Mesoscale Discussion 1852
   NWS Storm Prediction Center Norman OK
   1029 AM CDT Thu Jul 31 2025

   Areas affected...southeastern Pennsylvania...New
   Jersey...Delaware...central Maryland...and adjacent portions of
   northern Virginia...including DC

   Concerning...Severe potential...Watch possible 

   Valid 311529Z - 311800Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Thunderstorms are in the process of developing, and likely
   to gradually intensify through 1-4 PM EDT, accompanied by increasing
   risk for potentially damaging wind gusts.  A brief tornado might
   also be possible, particularly across parts of east central and
   southeastern Pennsylvania into central New Jersey.

   DISCUSSION...Perhaps aided by forcing for ascent downstream of a
   short wave perturbation progressing through the southern periphery
   of larger-scale positively tilted mid-level troughing overspreading
   the northern Atlantic Seaboard, thunderstorms appear to be
   initiating along a stalled to slow moving frontal zone, and east of
   a weak surface low, across the northern Mid Atlantic.  This is
   occurring as insolation within a boundary-layer characterized by
   seasonably high moisture content (including mid 70s F surface dew
   points) erodes inhibition.  

   Lapse rates are generally modest to weak, and the boundary layer is
   not forecast to become deeply mixed, due to the moisture, but
   profiles still appear supportive of CAPE on the order of 1000-2000
   J/kg.  Beneath the southern fringe of the stronger westerlies, where
   flow at altitudes as low as 500 mb is around 30-40 kt, deep-layer
   shear is strong and supportive of supercell structures, and perhaps
   an organizing cluster, with potential to produce strong surface
   gusts aided by heavy precipitation loading and evaporative cooling
   in downdrafts.  

   Thermodynamic profiles appear generally warm with limited potential
   for severe hail.  A brief tornado might not be out of the question,
   but low-level hodographs, particularly south of the surface front,
   are likely to remain generally weak.

   ..Kerr/Smith.. 07/31/2025

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...OKX...PHI...CTP...LWX...

   LAT...LON   39747713 40357698 40687612 40957453 40617390 39087505
               38667600 38597718 39107734 39747713 

   MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN

[AdamHLG]

Several factors have me betting the under today.  This is just a gut instinct.  Storms just fired a bit to the east of the metros now moving away - leaving cloud cover.  To the west I see activity but it would really need to generate.  Id be more excited if we had bright sun at 1:25 pm.    Not to be a Debbie but I am taking the under today for the widespread flooding.  I have not looked at a model sounding - I've just lived here most of my life.  Disclaimer:  I do not have a red met tag.     

[yoda]

Watch up till 8pm

[Kmlwx]

Downburst/microburst signal on the Montgomery County cell it looks like.

[yoda]

Preliminary Local Storm Report
National Weather Service Baltimore MD/Washington DC
148 PM EDT Thu Jul 31 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0139 PM     Waterspout       2 ENE Chase             39.38N  76.34W
07/31/2025                   ANZ531             MD   Trained Spotter

            Trained spotter reports a waterspout east of Chase, MD
            over the Bird River moving east.


&&

Event Number LWX2506473