2026 Mid-Atlantic Severe Storm General Discussion

[vortex95]

21 minutes ago, Maestrobjwa said:

I thank you for that and those links with great info and visuals--it's already starting to make more sense. Just that lottle hit goes a long way 

Wikipedia, believe it or not, has good objective wx definitions, and then you can look at all it references at the bottom, and go from there.

[vortex95]

18 hours ago, WEATHER53 said:

Is there a way to calculate how many mph thise strong  vs weak updrafts are moving at,?

It is not easy b/c it depends on the CAPE distribution in the vertical column.  In other words, you can't apply one updraft value at all levels of the atmosphere where there is CAPE b/c the amount of CAPE can vary a lot depending on the level you are at. 

Total CAPE does not necessarily tell the entire story as to full updraft potential.

Yes, generally more the CAPE the better, but it does not always mean the same type of svr wx or even things like lightning frequency or most efficient rainfall rates.

And CAPE (hence updraft potential) is almost never realized fully by a storm, b/c of 1) dry air entrainment and 2) precip loading.

And it goes one step further.  Updraft strength is also dependent on pressure perturbations induced by a mesocyclone.  For instance, mesocyclones are typically strongest at mid-levels.  So you actually have lowest pressure here.  This results in dynamic uplift b/c of the pressure deficit aloft.  Now, this is superimposed on CAPE that is present.  A mesocyclone present can effectively double the updraft strength that would exist just from CAPE alone, which is why supercell updrafts are so intense.

More CAPE down at low-levels is better for tornadogenesis b/c you increase updraft acceleration potential where it matters most (stretching of a vortex).  That's why we look at how much CAPE exists 0-3 km for one ingredient for tornado potential.
 
I'm just scratching the sfc here, but you get the idea.  It's hard to set nice, neat values in a given atmosphere due to so many factors.
 

[AlexD1990]

Tornado warning wicomico county 

[midatlanticweather]

Man, that warned cell in West central VA

[vortex95]

10 minutes ago, midatlanticweather said:

Man, that warned cell in West central VA

Are these things ever going to end today?  TORs issued this late in the evening for an approaching cold front are not common these parts, but we are dealing w/ a rather strong 500 trof for summer and a decent 250 speed max in the area.

And that's not something borderline either!  Small but quite intense mesocyclone.
 

[WEATHER53]

50 minutes ago, vortex95 said:

It not easy b/c it depends on the CAPE distribution in the vertical column.  In other words, you can't apply one updraft value at all levels of the atmosphere where there is CAPE b/c the amount of CAPE can vary a lot depending on the level you are at. 

Total CAPE does not necessarily tell the entire story as to full updraft potential.

Yes, generally more the CAPE the better, but it does not always mean the same type of svr wx or even things like lightning frequency or most efficient rainfall rates.

And CAPE (hence updraft potential) is almost never realized fully by a storm, b/c of 1) dry air entrainment and 2) precip loading.

And it goes one step further.  Updraft strength is also dependent on pressure perturbations induced by a mesocyclone.  For instance, mesocyclones are typically strongest at mid-levels.  So you actually have lowest pressure here.  This results in dynamic uplift b/c of the pressure deficit aloft.  Now, this is superimposed on CAPE that is present.  A mesocyclone present can effectively double the updraft strength that would exist just from CAPE alone, which is why supercell updrafts are so intense.

More CAPE down at low-levels is better for tornadogenesis b/c you increase updraft acceleration potential where it matters most (stretching of a vortex).  That's why we look at how much CAPE exists 0-3 km for one ingredient for tornado potential.
 
I'm just scratching the sfc here, but you get the idea.  It's hard to set nice, neat values in a given atmosphere due to so many factors.
 

Some of the  details of the upward column is like two hoses  but of different sizes so the flows are different?

[vortex95]

22 minutes ago, WEATHER53 said:

Some of the  details of the upward column is like two hoses  but of different sizes so the flows are different?

I am not versed in the exact physics of the processes, but I can say this.  "Fat" CAPE on a sounding plot is not the same as "skinny" CAPE.  "Fat" CAPE promotes more rapid updraft acceleration (image 1), and "skinny" CAPE promotes less rapid updraft acceleration (image 2).  If you want svr wx, "fat" CAPE is more conducive to produce it.  "Skinny" CAPE is better for heavy rainfall and flash flooding potential.
 

[yoda]

Looks like next week we go again

Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0226 AM CDT Wed Jul 22 2026

   Valid 251200Z - 301200Z

   ...DISCUSSION...
   ...Upper Midwest to Ohio Valley and Mid-Atlantic...

   An upper ridge centered over the High Plains will persist through
   the middle of next week. Meanwhile, upper troughing will be
   maintained over the eastern U.S. Periods of enhanced northwesterly
   flow aloft are expected across parts of the Upper Midwest/Great
   Lakes into parts of the Ohio Valley and Mid-Atlantic on the eastern
   periphery of the Plains upper ridge. Several shortwave impulses are
   forecast to develop southeast from Canada within this northwest flow
   regime. This could support daily severe thunderstorm chances from
   the Upper Midwest into the Ohio Valley, and possibly the
   Mid-Atlantic. However, the timing of these features is uncertain,
   and midlevel capping could limit the spatial extent of severe
   potential. It is likely that portions of the Upper Midwest into the
   Ohio Valley will need severe probabilities in later outlooks,
   particularly for Day 4-6/Sat-Mon, and possibly the mid-Atlantic by
   Day 7/Tue. However, confidence in where this risk will develop each
   day is too low for 15 percent delineation at this time.

   ..Leitman.. 07/22/2026

 

[frd]

1 minute ago, yoda said:

Looks like next week we go again

Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0226 AM CDT Wed Jul 22 2026

   Valid 251200Z - 301200Z

   ...DISCUSSION...
   ...Upper Midwest to Ohio Valley and Mid-Atlantic...

   An upper ridge centered over the High Plains will persist through
   the middle of next week. Meanwhile, upper troughing will be
   maintained over the eastern U.S. Periods of enhanced northwesterly
   flow aloft are expected across parts of the Upper Midwest/Great
   Lakes into parts of the Ohio Valley and Mid-Atlantic on the eastern
   periphery of the Plains upper ridge. Several shortwave impulses are
   forecast to develop southeast from Canada within this northwest flow
   regime. This could support daily severe thunderstorm chances from
   the Upper Midwest into the Ohio Valley, and possibly the
   Mid-Atlantic. However, the timing of these features is uncertain,
   and midlevel capping could limit the spatial extent of severe
   potential. It is likely that portions of the Upper Midwest into the
   Ohio Valley will need severe probabilities in later outlooks,
   particularly for Day 4-6/Sat-Mon, and possibly the mid-Atlantic by
   Day 7/Tue. However, confidence in where this risk will develop each
   day is too low for 15 percent delineation at this time.

   ..Leitman.. 07/22/2026

 

Machine learning did well in review,  pointing out days well in advance. At least from what I read 7 to 10 days ago. 

[Kmlwx]

Seems the GFS has a remnant EML in the vicinity for next week. 

[AlexD1990]

any chance for today?

[WEATHER53]

10 hours ago, vortex95 said:

I am not versed in the exact physics of the processes, but I can say this.  "Fat" CAPE on a sounding plot is not the same as "skinny" CAPE.  "Fat" CAPE promotes more rapid updraft acceleration (image 1), and "skinny" CAPE promotes less rapid updraft acceleration (image 2).  If you want svr wx, "fat" CAPE is more conducive to produce it.  "Skinny" CAPE is better for heavy rainfall and flash flooding potential.
 

You have been great to provide these last two discussions  to me 

[Herb@MAWS]

2 hours ago, AlexD1990 said:

any chance for today?

The deep moisture was pushed way south overnight, into southern Virginia. With the main front moving in later today there is a spotty chance for someone to get a localized shower or a storm. Odds greatly favor northern Virginia/Fredericksburg  area and points south/SE ….. as opposed to those of us up in the Baltimore area. Although I do notice the local forecast here/Columbia went from mostly sunny …. to 30% chance of a scattered shower/storm later in the afternoon during peak heating but that could be as much for just covering all the bases in case anything isolated pops up. Consider yourself lucky if you’re north of DC and get some rain this afternoon. Not expecting much if anything. 

[wawarriors4]

[vortex95]

8 hours ago, yoda said:

Looks like next week we go again

Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0226 AM CDT Wed Jul 22 2026

   Valid 251200Z - 301200Z

   ...DISCUSSION...
   ...Upper Midwest to Ohio Valley and Mid-Atlantic...

   An upper ridge centered over the High Plains will persist through
   the middle of next week. Meanwhile, upper troughing will be
   maintained over the eastern U.S. Periods of enhanced northwesterly
   flow aloft are expected across parts of the Upper Midwest/Great
   Lakes into parts of the Ohio Valley and Mid-Atlantic on the eastern
   periphery of the Plains upper ridge. Several shortwave impulses are
   forecast to develop southeast from Canada within this northwest flow
   regime. This could support daily severe thunderstorm chances from
   the Upper Midwest into the Ohio Valley, and possibly the
   Mid-Atlantic. However, the timing of these features is uncertain,
   and midlevel capping could limit the spatial extent of severe
   potential. It is likely that portions of the Upper Midwest into the
   Ohio Valley will need severe probabilities in later outlooks,
   particularly for Day 4-6/Sat-Mon, and possibly the mid-Atlantic by
   Day 7/Tue. However, confidence in where this risk will develop each
   day is too low for 15 percent delineation at this time.

   ..Leitman.. 07/22/2026

 

More NW flow!  And talk about the mean trough position remaining in the E!  The 12z ECMWF gets really amp'ed in 7 days.  So all sorts of convective possibilities, even if it is just big rains/lots of LTG!  Type of pattern is that if we can get any TC development off the E Coast, odds are we can get at least its tropical moisture here.

Some areas did quite well for rain ydy.  Max I could find for the DC area was 3.75" at Highland MD.  For SE VA where the biggest rains were fcst, ending 7am EDT, max of 6.00" at Kilmarnock VA (more fell after 7am).  So the HRRR did ok, and RRFS overdid it, esp. over SE VA, but at least it had the location of the max rainfall correct.

Still getting a feel for the RRFS.  I've heard not so good things about it here and there, but it is still non-operational, so maybe it will be adjusted/tweaked by the time it goes operational in Oct.


 

[ThePhotoGuy]

On 7/20/2026 at 9:58 AM, wxmeddler said:

That looks like 65 mph damage, there were pockets of 80 in there from TDWR. Locally more damaging than the '12 derecho. I think the derecho only had 50-65 in the Pasadena / Rivera Beach area.

Thanks! Appreciate the info been dealing with the storm frying the ONT terminal for FIOS. 

[yoda]

Outlooked on Day 5 from SPC... and sounds like we could see additional outlooks in the LR next weekend 

 

 

 

Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0337 AM CDT Fri Jul 24 2026

   Valid 271200Z - 011200Z

   ...DISCUSSION...
   ...Day 4/Monday...
   A prominent upper high will remain centered over the central and
   southern Plains with a belt of enhanced mid-level flow forecast
   along the periphery of that feature from the northern Plains into
   the Great Lakes. Within that flow regime, a short-wave trough is
   forecast to translate through the Great Lakes in tandem with a
   surface low and trailing cold front. A hot and moist boundary layer
   is expected ahead of the front, yielding moderate to strong
   instability by afternoon. Despite veered low-level winds,
   strengthening mid/upper-level winds in the exit region of a jet
   streak will contribute to sufficient vertical shear for organized
   severe storms across portions of the Great Lakes into the OH Valley
   Monday afternoon into night.


   ...Day 5/Tuesday...
   The Day 4/Monday short-wave trough is forecast to evolve into an
   upper low across southwest ON and the lower Great Lakes with an
   associated belt of stronger cyclonic flow developing from the OH
   Valley into the southern Mid-Atlantic and NC. At the surface, an
   area of low pressure will develop from the lower Great Lakes into
   central NY with a trailing cold front advancing through the upper OH
   Valley, central Appalachians, and Mid-Atlantic.

   Thunderstorms may be ongoing Tuesday morning along and ahead of the
   front from the lower Great Lakes and upper OH Valley into the
   Mid-Atlantic. Stronger heating is anticipated to the south of the
   early-day storms from the southern Mid-Atlantic into NC, where
   moderate to potentially strong instability is forecast. The
   strongest instability will coincide with modestly strong deep-layer
   shear to support some severe weather threat in those areas Tuesday
   afternoon and evening.


   ...Days 6-8/Wednesday-Friday...
   The 00Z ensemble means depict a slight westward regression of the
   dominant mid/upper-level high with persistent troughing along the
   East Coast. On the periphery of the high, a notable short-wave
   trough is forecast to progress from the Canadian Rockies on
   Wednesday through the Prairie Provinces on Thursday with modest
   height falls along the international border. By Friday, there is
   some model signal for another short-wave trough to move into the
   upper MS Valley and Great Lakes regions. At the surface, a more
   substantial cold front is projected to move into the northern Plains
   on Thursday, and the upper Midwest and Great Lakes by Friday. 

   A few severe storms appear possible in the Southeast and northern
   Plains on Wednesday, the northern Plains on Thursday, and the upper
   Midwest into the Great Lakes on Friday. Confidence in the magnitude
   and areal extent of the threat is currently too low to delineate
   additional areas.

   ..Mead.. 07/24/2026

 

[yoda]

Morning AFD from LWX mentions "ridge rollers"

KEY MESSAGE 2...Returning to a summer-like pattern next week.

Coming off of the weekend, an upper-level trough begins to dig into
the northeastern U.S. This will usher in the potential for organized
convection early to mid week. In spite of multiple frontal passages
during the period, next week could carry a return to summer-like
conditions with heat indices in the mid 90s to near 100 degrees.

The key players will be a longstanding upper ridge across the
southwestern U.S. into the southern/central Great Plains, a deep
upper low near Hudson Bay, and longwave trough over the eastern U.S.
While ensemble solutions do not show a more formidable shortwave
tracking across the area, the setup certainly lends itself to a more
active pattern. A series of "ridge rollers" are likely to cross the
northern tier of the country before crossing the Great Lakes and
northeastern states. At this juncture, the machine-learning
algorithms favor an uptick in convection on Monday into Tuesday.
This would present the most likely opportunity for any severe
thunderstorms. A progressive pattern aloft will bring a cold front
through the region on Tuesday evening/night, with a secondary
boundary on its heels. While temperatures remain seasonable in this
mid/late week pattern shift, dew points slowly come down to finish
out the month of July.