2025 Severe Weather General Discussion

[Kmlwx]

Many of the CAMs are pretty underwhelming in terms of sim reflectivity. It will all be a question of whether there is enough forcing and the cap being weak enough to break. I still think the thoughts of the threat being isolated but intense are solid. Wherever a cell develops/tracks could get really hefty hail...

I think for the majority of the area this could be a dud. The other thing I saw at least one model showing was a pretty good "leftover" line coming into the area Saturday AM from the west. 

[Eskimo Joe]

1 hour ago, Kmlwx said:

Many of the CAMs are pretty underwhelming in terms of sim reflectivity. It will all be a question of whether there is enough forcing and the cap being weak enough to break. I still think the thoughts of the threat being isolated but intense are solid. Wherever a cell develops/tracks could get really hefty hail...

I think for the majority of the area this could be a dud. The other thing I saw at least one model showing was a pretty good "leftover" line coming into the area Saturday AM from the west. 

I think tomorrow and Saturday are going to feature one or two decent cells that drop some good hail, but there will be more famine than feast. Saturday might be a decent elevated convection.

[WxUSAF]

12z hrrr is fun

[SnowenOutThere]

45 minutes ago, Eskimo Joe said:

I think tomorrow and Saturday are going to feature one or two decent cells that drop some good hail, but there will be more famine than feast. Saturday might be a decent elevated convection.

Will the storms tomorrow have good photogenic supercellular structure that would be worth a local chase? Also where in the area would you generally target?

[Kmlwx]

30 minutes ago, WxUSAF said:

12z hrrr is fun

The complex that arrives after dark reminds me of a way toned down June 2012 lol. Obviously temps nowhere close to that. But a line surging across the mountains. 

[dailylurker]

47 minutes ago, Kmlwx said:

The complex that arrives after dark reminds me of a way toned down June 2012 lol. Obviously temps nowhere close to that. But a line surging across the mountains. 

Today has a sneaky thunderstorm day feel and look to it. 

[yoda]

12z NAM Nest soundings suggest nastiness tomorrow evening into nighttime 

[yoda]

Oh okay then - I know this is more just to the S and W of most of us... But still don't see hatched hail around here very often... @high risk @George BM @Kmlwx @Eskimo Joe

 

[NorthArlington101]

Last time I tried to fly into BWI storms screwed me. 2/2 with my flight late tonight?

[yoda]

Oh

Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1128 AM CDT Thu May 15 2025

   Valid 151630Z - 161200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS
   EAST-CENTRAL MINNESOTA...MUCH OF WISCONSIN...SOUTHERN AND WESTERN
   LOWER MICHIGAN...NORTHEAST ILLINOIS...NORTHERN INDIANA AND NORTHWEST
   OHIO...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
   VIRGINIA AND NORTHEAST NORTH CAROLINA...
   
...


   ...Central Appalachians/Mid-Atlantic...  
   Large-scale height rises are expected across the region, but
   diurnal heating and orographic effects will aid in thunderstorm
   development across the higher terrain this afternoon. Northwesterly
   flow aloft will favor a southeastward storm motion within an
   environment of moderate/locally strong instability. 35-45 kts of
   northwesterly deep shear is anticipated, supporting supercell
   structures and clusters, posing a risk for large hail and damaging
   winds. The overall hodograph structure and resulting storm motion
   appears favorable for some very large hail over 2" in diameter as
   well.

   ..Mosier.. 05/15/2025

 

[yoda]

SLGT risk up for the entire LWX CWA for tomorrow on 1730z SPC OTLK.  ENH knocking on the door of our western zones 

[yoda]

 

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1220 PM CDT Thu May 15 2025

   Valid 161200Z - 171200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   SOUTHEAST MISSOURI...SOUTHERN ILLINOIS/INDIANA...AND CENTRAL AND
   WESTERN KENTUCKY...

   ...SUMMARY...
   A regional outbreak of severe thunderstorms is likely across parts
   of the middle Mississippi and Ohio Valleys Friday afternoon into
   Friday night.  This may include a few intense supercells posing a
   risk for large hail and tornadoes.  During the evening into the
   overnight hours, this will include an upscale growing and organizing
   bowing line of storms posing a risk for strong, damaging winds and a
   continuing risk for tornadoes.

   ...A regional outbreak of severe storms is expected on Friday across
   portions of the Mid-South to the Ohio Valley...

   ...Synopsis...

   An upper cyclone over the Upper Midwest and attendant shortwave
   trough will develop east/northeast across much of the Midwest and TN
   Valley. A swath of strong mid/upper southwesterly flow will
   accompany this system. Forecast guidance shows a 70-90 kt 500 mb jet
   spreading across the Mid-MS to OH Valley, while 850-700 mb increases
   to 40-60 kt by midday. This will result in supercell wind profiles,
   support widespread organized convection. Favorable deep-layer shear
   will extend downstream into the central Appalachians and
   Mid-Atlantic vicinity as well.

   At the surface, low pressure will shift east from northern MN into
   the Upper Great Lakes. A warm from southern MO into the OH Valley
   Friday morning is forecast to lift northward through the afternoon,
   allowing rich boundary layer moisture (mid/upper 60s F dewpoints) to
   overspread much of the Lower OH Valley, with a large warm sector in
   place across a broad region from east TX to the Great Lakes and
   eastward toward the Mid-Atlantic coast. Corridors of moderate to
   strong destabilization during the day and into the nighttime hours
   will support several areas of severe storms from east Texas into
   much of the Midwest and the Mid-Atlantic, some of which could be
   significant.

   
 
   ...

   

   ...Central Appalachians to Mid-Atlantic...

   Thunderstorms may be ongoing Friday morning across parts of PA and
   spread east/southeast through early afternoon as a lead upper
   shortwave impulse moves across the Northeast. Moistening and heating
   ahead of this activity will support moderate to strong
   destabilization, especially from the Chesapeake Bay vicinity
   southward across the VA/NC Piedmont. The initial round of
   thunderstorms may pose a risk for locally strong gusts and hail
   before moving offshore the NJ/DE/MD coast during the early
   afternoon.

   During the evening/overnight hours, a mature bowing MCS is expected
   to move over the WV/VA/NC mountains and spread east across the
   region, posing a risk for swaths of strong to damaging wind gusts.
   Forecast guidance varies in timing and exact evolution of this
   system across the region, but portions of the area may need higher
   probabilities in subsequent outlooks.

[Eskimo Joe]

SPC raises a good point, it ultimately comes up to how strong the EML is an whether it persists across the mountains. If we get a good chunk of that to get overhead, then it's going to be a fun day.

[Kmlwx]

One mostly non-scientific thing is we tend to have "streaks"

So a cluster of 2 days of decent severe threat would be fitting with EML influence. As @Eskimo Joe has said for years...the EML/MLLRs really can allow for more wiggle room in the other parameters. 

Also...it could be the start of a stretch when maybe we get some more storm events. Not saying back-to-back but perhaps not going weeks between storm threats. 

[Kmlwx]

Also - spam posting but oh well...

Not saying it WILL happen - but some of our higher end days have come when there's a higher risk a day or two ahead to our west/NW and then SPC adjusts in real time to extend the threat into our region. If instability doesn't wane too much after dark tomorrow night - I think the overnight period into early Sat AM could be some really rough weather. 

Again...NOT the same setup but remember June 2012 I think the day before we had a 5%...

ETA: Yes...DC proper didn't even have a slight risk on the DAY 1 1630z outlook that day. Talk about "that escalated quickly"

[Kmlwx]

The 12z runs of the NSSL-MPAS triplets all have a robust MCS/line coming through Fri night into Sat AM. 

[yoda]

Watch coming soon -

https://www.spc.noaa.gov/products/md/md0788.html

 

Mesoscale Discussion 0788
   NWS Storm Prediction Center Norman OK
   0123 PM CDT Thu May 15 2025

   Areas affected...portions of eastern West Virginia and much of
   Virginia

   Concerning...Severe potential...Watch possible 

   Valid 151823Z - 152000Z

   Probability of Watch Issuance...60 percent

   SUMMARY...The severe threat should increase over the next few hours.
   Multicells and supercells will be the primary storm mode, with
   severe wind and hail the main threats. A few instances of 2+ inch
   diameter hail are possible. A Severe Thunderstorm Watch will
   eventually be needed.

   DISCUSSION...Satellite imagery shows agitated cumulus along the
   WV/VA border, driven primarily by boundary layer destabilization,
   along with orographic lift associated with the Appalachians. Surface
   temperatures have already warmed into the mid to upper 70s F to the
   immediate lee of the Appalachians, where upper 60s F dewpoints,
   beneath the eastward extent of an EML plume, supports 1500+ J/kg
   MLCAPE. The 17Z RNK observed sounding shows 8 C/km 700-500 mb lapse
   rates and the freezing level around 600 mb, beneath where most of
   the CAPE resides, along with modestly elongated hodographs. Such
   conditions support supercells capable of severe gusts and large
   hail, including a few instances of 2+ inch in diameter stones. Given
   a gradually increasing severe threat, a Severe Thunderstorm Watch
   will eventually be needed.

   ..Squitieri/Mosier.. 05/15/2025

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

   ATTN...WFO...AKQ...LWX...RNK...RLX...

   LAT...LON   36608017 36768076 37298113 37938092 38388044 38797971
               38967837 38617777 37937732 37257730 36797770 36637848
               36608017 

   MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN

[North Balti Zen]

Quote

agitated cumulus

Um. That's just a perfect AmWx user name - anyone who reads and hasn't signed up yet should do so and grab it...

[yoda]

Mention of "some thunderstorms may be severe" in the updated zones for Friday night 

[Paleocene]

18z HRRRRR has that bow flying across VA from around 16z-20z tomorrow. Mostly south of i-66/us50.