2026 Mid-Atlantic Severe Storm General Discussion

[high risk]

1 hour ago, Kmlwx said:

The CAMs are really all over the place (seems to be a common theme this year). I could technically see chunks of the area getting skunked through the whole week...The game of weather lottery! 

 Even this evening has a lot of questions.  While there is general agreement that a cluster of storms drops south through NJ/DE, some of the CAMs have storms building back to the west and catching much of central MD.

[yoda]

Severe Thunderstorm Watch up until midnight for NE MD and DE 

URGENT - IMMEDIATE BROADCAST REQUESTED
   Severe Thunderstorm Watch Number 638
   NWS Storm Prediction Center Norman OK
   435 PM EDT Tue Sep 1 2026

   The NWS Storm Prediction Center has issued a

   * Severe Thunderstorm Watch for portions of 
     Delaware
     Northeast Maryland
     New Jersey
     Southern New York
     Central and Eastern Pennsylvania
     Coastal Waters

   * Effective this Tuesday afternoon from 435 PM until Midnight
     EDT.

   * Primary threats include...
     Scattered damaging wind gusts to 70 mph likely
     Scattered large hail events to 1.5 inches in diameter possible
     A tornado or two possible

   SUMMARY...Supercell thunderstorms should pose a threat for large
   hail this afternoon as they track east-southeastward across the
   northern Mid-Atlantic. The threat for scattered severe/damaging
   winds should increase this evening as one or more clusters develops.
   A tornado or two may also occur with any sustained supercell.

 

[yoda]

 

[The Dude]

19 minutes ago, high risk said:

 Even this evening has a lot of questions.  While there is general agreement that a cluster of storms drops south through NJ/DE, some of the CAMs have storms building back to the west and catching much of central MD.

Dumb question:  When folks are referencing the CAMs here, which models are you looking at.  I assume the HRRR, NAM Nest, RRFS.  Any others?  FV3, WRF-ARW? 

[high risk]

1 hour ago, The Dude said:

Dumb question:  When folks are referencing the CAMs here, which models are you looking at.  I assume the HRRR, NAM Nest, RRFS.  Any others?  FV3, WRF-ARW? 

 

        Correct.   HRRR, NAM Nest, RRFS, and the three Hires Windows (FV3, ARW, ARW2).

 

[yoda]

12 minutes ago, high risk said:

 

        Correct.   HRRR, NAM Nest, RRFS, and the three Hires Windows (FV3, ARW, ARW2).

 

What about the MPAS?

[high risk]

24 minutes ago, yoda said:

What about the MPAS?

      I personally don't look at it very often, as it's still being tweaked.   That said, it's the future, so as it matures, I'll definitely be looking more often.   

[vortex95]

Around 8pm this evening looking N from the N side of the Beltway, I could see robust ACCAS, almost MDT CU.  So there is your elevated instability in place.  RRFS MPAS suggest a few cells may form in the DC area the next few hrs (DCA already reporting LTGIC NE), and we have those storms in the far nrn Delmarva w/ a distinct OFB.

The EIR sat loop is impressive.  Look at the backbuilding and sharp cloud temp gradient in far NE MD.  NW flow is neat!

Got this loop from here.  Nice sector for the region!
https://whirlwind.aos.wisc.edu/~wxp/goes16/ircm/goes16_ne_3h.html

[dailylurker]

I see our storms for later on over Lake Erie this morning. Lake Ontario also has a nice batch.

[WxUSAF]

1 hour ago, dailylurker said:

I see our storms for later on over Lake Erie this morning. Lake Ontario also has a nice batch.

10z hrrr made a big flip to carrying that Erie (I call it Lake Freedom now) cluster into central MD

[TSSN+]

5 minutes ago, WxUSAF said:

10z hrrr made a big flip to carrying that Erie (I call it Lake Freedom now) cluster into central MD

The models haven’t done well showing the storms. Yesterday those storms that ripped ne and eastern Pa weren’t super well shown either. If that area holds together as the atmosphere gets unstable it could be an interesting afternoon. 

[dailylurker]

5 minutes ago, WxUSAF said:

10z hrrr made a big flip to carrying that Erie (I call it Lake Freedom now) cluster into central MD

This post caused an eagle to gain it's wings.

It should be a fin day of radar watching. I could really go for some severe. I might cut out of work around 2 and do a lightning chase this afternoon. 

[batmanbrad]

the 2AM SPC outlook pulled the 2% TOR risk down into much of our area, and the 30% wind prob into much of the northern parts of our area.  CSU-MLP charts keep most of the TOR north of us but does agree with the 30+% wind area in our northern areas for today and keeps that going with even more of our area covered into tomorrow.  Let's see if this holds when the 9AM SPC outlook for today comes out.  Still many variables to sort out but should be an interesting next 36 hours or so to track!

[SolidIcewx]

Optimally, id like to see it develop more west as the morning goes on. That way it increases the chances of a wider hit for us all this evening.

[TSSN+]

Got multiple tornado warnings and severe warnings but no watch up there. 

[SUNYGRAD]

The HRDPS reflectively did pretty good on the 06z and 12Z runs yesterday with storms over central PA yesterday extending SE, and the most current SPC storm reports (from yesterday).  Today's HRDPS 6z seems to do ok thus far, but the southern storm complex (modelled) is a little farther north.  Still doing better than most of the other short-term modeling.  Thought I would chime in, since I have family in NY, friends in PA, and was watching the evolution yesterday and providing some short-term forecasts.  Like all the discussions.

[yoda]

1300z SPC OTLK disco says the morning convection is causing question marks for later 

 

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0723 AM CDT Wed Sep 02 2026

   Valid 021300Z - 031200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
   THE NORTHEAST STATES...AND ACROSS PARTS OF MONTANA...

   ...SUMMARY...
   Severe thunderstorms are possible across portions of the eastern
   Great Lakes to the Mid-Atlantic today and tonight. Damaging wind
   gusts are the main threat, though some large hail and a few
   tornadoes may also occur. Scattered severe gusts and more sporadic
   occurrences of large hail appear possible from the northern Rockies
   into northern High Plains today into night.

   ...Northeast States...
   A complex but potentially active convective day is in store for
   parts of the northeast US today.  A fast-moving MCS and associated
   mid-level shortwave trough is over Lake Michigan.  This system is
   forecast to track rapidly eastward across Lower MI and southwest ON
   this morning before emerging into western NY/PA this afternoon.  A
   consensus of overnight CAM solutions indicate this will be the focus
   for strong-severe thunderstorms that track east-southeastward during
   the afternoon and evening toward the Mid-Atlantic coast.  Ample
   low-level moisture is present in this corridor.  This along with
   daytime heating well into the 80s and steep low-level lapse rates
   will favor damaging wind gust potential in the strongest storms.  A
   north-south surface boundary is expected to lie from central NY into
   east-central PA this afternoon, where low-level shear will be
   locally enhanced to pose some risk of a few tornadoes.  

   The primary uncertainty for a more widespread severe event today is
   the presence of considerable morning convection currently over
   northwest PA and western NY.  These storms are well-ahead of the
   main forcing feature, and decrease confidence in significant
   destabilization over the primary risk area this afternoon.  These
   early storms may pose a damaging wind and hail risk through the day,
   especially after a few hours of heating.

[yoda]

LWX AFD from this morning does also state severe storms are possible well into the night

KEY MESSAGE 1...Daily severe weather threat through the end of
the week.

Multiple rounds of thunderstorms, some likely severe with
damaging winds, are likely today through Friday as upper level
disturbances move from the Great Lks into the Mid Atlantic
states. Already seen a small cluster of thunderstorms over south
central Pennsylvania that will move through the area later this
morning. Two additional rounds of thunderstorms seem likely
today, one this afternoon, and a second one late this evening
into the overnight hours tonight into Thursday. Thunderstorms
will ride southeast along and north of a backdoor front
currently pushing south through northern VA and southern MD as
seen on TDWRs and wind shifts to the NE at IAD and DCA a couple
of hours ago. The severe threat will not be necessarily tied to
the afternoon and evening hours as record warm nighttime
temperatures and high humidity yield strong instability and
keep thunderstorms going strong well into the overnight hours.

By Friday, cold front should have cleared much of the forecast
area causing a stabilizing effect limiting the risk of severe
weather, but showers and thunderstorms will still be possible
north of the sfc front.

[SolidIcewx]

11 minutes ago, yoda said:

LWX AFD from this morning does also state severe storms are possible well into the night

KEY MESSAGE 1...Daily severe weather threat through the end of
the week.

Multiple rounds of thunderstorms, some likely severe with
damaging winds, are likely today through Friday as upper level
disturbances move from the Great Lks into the Mid Atlantic
states. Already seen a small cluster of thunderstorms over south
central Pennsylvania that will move through the area later this
morning. Two additional rounds of thunderstorms seem likely
today, one this afternoon, and a second one late this evening
into the overnight hours tonight into Thursday. Thunderstorms
will ride southeast along and north of a backdoor front
currently pushing south through northern VA and southern MD as
seen on TDWRs and wind shifts to the NE at IAD and DCA a couple
of hours ago. The severe threat will not be necessarily tied to
the afternoon and evening hours as record warm nighttime
temperatures and high humidity yield strong instability and
keep thunderstorms going strong well into the overnight hours.

By Friday, cold front should have cleared much of the forecast
area causing a stabilizing effect limiting the risk of severe
weather, but showers and thunderstorms will still be possible
north of the sfc front.

A nocturnal training event would be great!

[yoda]

Severe Thunderstorm Watch up for Central and Southern PA until 2pm

[high risk]

10 minutes ago, yoda said:

Severe Thunderstorm Watch up for Central and Southern PA until 2pm

   Hard not to think that this cluster will persist south of the M-D line, although instability isn't what it could have been, given that the eastern half of the area has easterly winds behind that weak backdoor front.

[Kmlwx]

The trajectory looks great especially for the north and eastern quarter/half of the area. But it does seem like there is a tendency to build convection on the western side of the complex. We'll have to see how the intensity trends as it gets closer but for now that line/bow looks fierce. 

[MN Transplant]

5 minutes ago, high risk said:

   Hard not to think that this cluster will persist south of the M-D line, although instability isn't what it could have been, given that the eastern half of the area has easterly winds behind that weak backdoor front.

Interesting to see that the NAM ended up being right about the front, but temps are already above the NAM high temp guidance.

[WxUSAF]

That cluster is hauling ass

[jewell2188]

Definitely looks like a north of 66 deal 

[mappy]

It’s cloudy after some morning sun. One would think that MCS would get to me eventually 

[SolidIcewx]

Working in central PG county. I can see the high cloud cover making its way south.

[batmanbrad]

on its current trajectory, the western end of that complex will get to approximately the Loudoun/Montgomery county line assuming it holds together...