2022 Mid-Atlantic Severe Wx Thread (General Discussion Etc)

[Kmlwx]

Just now, yoda said:

Reviewing it... I like how the morning Day 2 was like oh 15% off to our west... afternoon update hatched introduced lol

June 2008 was one of our significant stretches. Will be interesting to see if any of the other June 2008 events pop up in the next few weeks. 

[yoda]

Just now, Kmlwx said:

June 2008 was one of our significant stretches. Will be interesting to see if any of the other June 2008 events pop up in the next few weeks. 

Wonder if its last time we had 30% hatched hail over us

[yoda]

Probably won't see hail sizes this large again in a watchbox for our region unless we get some huge EML lol

URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 551
   NWS STORM PREDICTION CENTER NORMAN OK
   120 PM EDT MON JUN 16 2008
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
   
          SOUTHWESTERN CONNECTICUT
          DISTRICT OF COLUMBIA
          DELAWARE
          MARYLAND
          NEW JERSEY
          SOUTHEAST NEW YORK
          PARTS OF SOUTHERN AND EASTERN PENNSYLVANIA
          MUCH OF NORTHERN AND CENTRAL VIRGINIA
          PARTS OF EASTERN WEST VIRGINIA
          COASTAL WATERS
   
   EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 120 PM UNTIL 900
   PM EDT.
   
   HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80
   MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

[Kmlwx]

June is definitely a month we can really go wild with severe in these parts. EML helps, of course, as does having decent shear before things get weak in that regard into summer - and hot hot hot temps to fuel storms. 

[George BM]

30 minutes ago, yoda said:

Probably won't see hail sizes this large again in a watchbox for our region unless we get some huge EML lol

URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 551
   NWS STORM PREDICTION CENTER NORMAN OK
   120 PM EDT MON JUN 16 2008
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
   
          SOUTHWESTERN CONNECTICUT
          DISTRICT OF COLUMBIA
          DELAWARE
          MARYLAND
          NEW JERSEY
          SOUTHEAST NEW YORK
          PARTS OF SOUTHERN AND EASTERN PENNSYLVANIA
          MUCH OF NORTHERN AND CENTRAL VIRGINIA
          PARTS OF EASTERN WEST VIRGINIA
          COASTAL WATERS
   
   EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 120 PM UNTIL 900
   PM EDT.
   
   HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80
   MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

Where did you retrieve this?... As I cannot seem to retrieve it from SPCs Severe Watches archive ATM. 

[yoda]

2 minutes ago, George BM said:

Where did you retrieve this?... As I cannot seem to retrieve it from SPCs Severe Watches archive ATM. 

https://www.spc.noaa.gov/exper/archive/event.php?date=20080616

Left side 

[George BM]

5 minutes ago, yoda said:

https://www.spc.noaa.gov/exper/archive/event.php?date=20080616

Left side 

This is actually the site that wasn't working for me. But now it finally started loading. But still, thank you. 

[George BM]

9 minutes ago, yoda said:

https://www.spc.noaa.gov/exper/archive/event.php?date=20080616

Left side 

BTW, with that watch the probs were:

TOR: 20/5

WIND: 80/40

HAIL: 70/30

And just in case you're curious the first 20080604 watch had the same wind and hail probs but with 40/20 tornado probs.

[Eskimo Joe]

2 hours ago, Kmlwx said:

June is definitely a month we can really go wild with severe in these parts. EML helps, of course, as does having decent shear before things get weak in that regard into summer - and hot hot hot temps to fuel storms. 

We fight so many subtle geographic features here. These can be overcome with  good EML and shear. Throw in a NW flow event and you're talking dirty.

[Kmlwx]

43 minutes ago, Eskimo Joe said:

We fight so many subtle geographic features here. These can be overcome with  good EML and shear. Throw in a NW flow event and you're talking dirty.

I finally have a weekend where I'm not running around a ton. Getting some outdoor activities in today, but hoping to look at the next period in more detail this evening 

[jacindc]

Probably won't see hail sizes this large again in a watchbox for our region unless we get some huge EML lol

URGENT - IMMEDIATE BROADCAST REQUESTED  SEVERE THUNDERSTORM WATCH NUMBER 551  NWS STORM PREDICTION CENTER NORMAN OK  120 PM EDT MON JUN 16 2008  THE NWS STORM PREDICTION CENTER HAS ISSUED A  SEVERE THUNDERSTORM WATCH FOR PORTIONS OF          SOUTHWESTERN CONNECTICUT         DISTRICT OF COLUMBIA         DELAWARE         MARYLAND         NEW JERSEY         SOUTHEAST NEW YORK         PARTS OF SOUTHERN AND EASTERN PENNSYLVANIA         MUCH OF NORTHERN AND CENTRAL VIRGINIA         PARTS OF EASTERN WEST VIRGINIA         COASTAL WATERS  EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 120 PM UNTIL 900  PM EDT.HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80  MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

Hail the size of canned hams?

(Reference for Gen Xers)

[Kmlwx]

So my best friend CIPS isn't particularly exciting for anything both in the standard and extended range. 

HOWEVER, I'd be lying if I said i wasn't kind of excited for the day 10-15 period. GFS/Euro and their ensembles have some form of a big ridge to our west setting up. The exact position and "tilt" of this ride varies (of course...this far out it's to be expected). But almost all of them put us on the eastern side of a sprawling ridge...could be good for NW flow events if the stars align. Not saying the D-word this far out - but we might start to see some big time analogs on CIPS if the general looks keeps up. The 6z GFS has a high parameter day or two around the 270ish hour mark (usually GFS is pretty conservative on supercell composite paramter). 

This is from the 0z GEFS - I'd take this as a severe weenie

And here's the Euro Ensembles

 

So you can see the ridge axis and position varies - but on that EC ENS run it kind of wiggles around a bit before and after this frame. 

[George BM]

2 minutes ago, Kmlwx said:

So my best friend CIPS isn't particularly exciting for anything both in the standard and extended range. 

HOWEVER, I'd be lying if I said i wasn't kind of excited for the day 10-15 period. GFS/Euro and their ensembles have some form of a big ridge to our west setting up. The exact position and "tilt" of this ride varies (of course...this far out it's to be expected). But almost all of them put us on the eastern side of a sprawling ridge...could be good for NW flow events if the stars align. Not saying the D-word this far out - but we might start to see some big time analogs on CIPS if the general looks keeps up. The 6z GFS has a high parameter day or two around the 270ish hour mark (usually GFS is pretty conservative on supercell composite paramter). 

This is from the 0z GEFS - I'd take this as a severe weenie

And here's the Euro Ensembles

 

So you can see the ridge axis and position varies - but on that EC ENS run it kind of wiggles around a bit before and after this frame. 

Central US ridges and NW flow over the Mid-Atlantic in June = a happy weenie

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A happy SEVERE weenie people! Calm down. 

[Kmlwx]

Just now, George BM said:

Central US ridges and NW flow over the Mid-Atlantic in June = a happy weenie

A happy SEVERE weenie people! Calm down. 

@ravensrule would be in here in 2 seconds with a comment like that. 

I've just gone down the rabbit hole reading the "Noteworthy Derecho Events" page on the SPC site. 

[Kmlwx]

Here's some selected ones - along with the PSU Reanalysis maps for each. 

1) July 4-5, 1980 - https://www.spc.noaa.gov/misc/AbtDerechos/casepages/jul4-51980page.htm

 

2) July 10-11, 2011 (I don't remember this one for some reason!)

 

Not even going to include June 29, 2012 as we all know that one. 

[Kmlwx]

We'll have to watch for the EML aspect of the upcoming period as well. The more recent GFS runs have sent most of the EML advecting north and east and not really into our region. However, the 18z GFS yesterday did move a pretty good EML for a big part of the east coast in the 270hr time frame. That stuff is far from being worked out. As stated above, the upper air pattern is the only thing I'm looking at with any seriousness this far out. Looking at where any EML is situated this far out is like tracking the rain/snow line in a fantasy 240+hr GFS snowstorm in winter. 

Guessing we have "higher than normal" odds at some decent severe...but whether the X-factors line up for us will determine (and luck, of course) whether it's something memorable or just a few days of hot weather afternoon storms with a pulsey nature. 

Reminder that our derecho climo around here is 1 derecho every 4 years (I think it's a bit higher to the north and west). 

[Kmlwx]

12z GFS continues to look intriguing around the June 15th timeframe. 

Afternoon of June 15th on this run has 5000+ SBCAPE, nearly 4000 MLCAPE (over 4000 to the NW of the metro areas). Ripe supercell composite maps as well. Really impressive considering it's the GFS and not the NAM. Again, it's a eternity away at that timeframe...but it keeps the general potential on the table. 

Pulling a model forecast sounding from near the M/D line in northern Maryland yields this on the College of Dupage site - 

SFC CAPE = 5425
ML CAPE = 4554
SFC LI = -12

Sfc to 1km shear = 18kts
Sfc to 3km shear = 32kts

Sfc to 1km SRH = 116

Supercell Composite = 26.0
STP (cin) = 4.2
STP (fix) = 3.6

PWATS over 2 inches. 

[George BM]

2 hours ago, Kmlwx said:

12z GFS continues to look intriguing around the June 15th timeframe. 

Afternoon of June 15th on this run has 5000+ SBCAPE, nearly 4000 MLCAPE (over 4000 to the NW of the metro areas). Ripe supercell composite maps as well. Really impressive considering it's the GFS and not the NAM. Again, it's a eternity away at that timeframe...but it keeps the general potential on the table. 

Pulling a model forecast sounding from near the M/D line in northern Maryland yields this on the College of Dupage site - 

SFC CAPE = 5425
ML CAPE = 4554
SFC LI = -12

Sfc to 1km shear = 18kts
Sfc to 3km shear = 32kts

Sfc to 1km SRH = 116

Supercell Composite = 26.0
STP (cin) = 4.2
STP (fix) = 3.6

PWATS over 2 inches. 

I really hope we get a pattern similar to what's being advertised by the GFS. Obvious uber-long range caveat aside, that would easily be a MOD risk worthy day from the MidAtl up into the Northeast verbatim. 

[Kmlwx]

8 minutes ago, George BM said:

I really hope we get a pattern similar to what's being advertised by the GFS. Obvious uber-long range caveat aside, that would easily be a MOD risk worthy day from the MidAtl up into the Northeast verbatim. 

As advertised...the GFS would seem to be a single day (maybe 2) potential and then things clear out. But you'd think if that ridge setup shop for any decent length of time, as the window gets closer more sustained chances could show up. Reminds me a bit of model watching for KU patterns in winter - if a window is real, threats show up later. 

[Eskimo Joe]

Siri, tell me what starts with D and ends in echo

[Maestrobjwa]

2 hours ago, Eskimo Joe said:

Siri, tell me what starts with D and ends in echo

C'mon man...I don't know much about severe, but I can't imagine you can predict that ahead of time, lol

[Kmlwx]

6 hours ago, Maestrobjwa said:

C'mon man...I don't know much about severe, but I can't imagine you can predict that ahead of time, lol

You can't. But the pattern fits. You also can't predict a KU 10 days out, but you can assess that the pattern could be favorable! 

[midatlanticweather]

I know this is days late! This was what the storms that came through and caused the wind damage and hail last week looked like as they were going through Purcellville. I did not take this photo and take no credit for them (Here is the original https://www.facebook.com/photo?fbid=3196421617280200&set=pcb.2254113818069568) but I saw the same thing! Looked very impressive! What do you all think these are? Reminds me of a rotating storm with a wall cloud.

 

[yoda]

Hmmm

 

 

[high risk]

2 hours ago, midatlanticweather said:

I know this is days late! This was what the storms that came through and caused the wind damage and hail last week looked like as they were going through Purcellville. I did not take this photo and take no credit for them (Here is the original https://www.facebook.com/photo?fbid=3196421617280200&set=pcb.2254113818069568) but I saw the same thing! Looked very impressive! What do you all think these are? Reminds me of a rotating storm with a wall cloud.

 

          A supercell (rotating storm) tracked right across that area on Thursday, so I think that your guess is spot on.      That's clearly a wall cloud extending beneath the rain-free base, with the rain and hail (note the green hues) core on the right side of the picture

[midatlanticweather]

8 minutes ago, high risk said:

          A supercell (rotating storm) tracked right across that area on Thursday, so I think that your guess is spot on.      That's clearly a wall cloud extending beneath the rain-free base, with the rain and hail (note the green hues) core on the right side of the picture

Several just east of me were saying they thought they had a tornado. I was hoping to look at the radar at the time, but was unable. I do not know if the NWS was going to take a look or not. BTW, I was pretty sure that is what I was seeing, but I was not going to just say it was without others agreeing. Anyways, I went right under it, but was in a car and not a good spot to photograph it. This was exactly what I saw as well. 

 

[yoda]

So Wednesday evening into Wednesday night looks interesting per afternoon LWX AFD 

The cold front approaching from the west is forecast to pass through
our region sometime late Tuesday evening and into Wednesday. There
remains some uncertainty on the timing of the frontal passage and
how far south of our region it will sink on Wednesday. Based on
current guidance, the front should pass fully through the region
during Wednesday morning. The GFS and Euro models have the front
stalling just south of our region on Wednesday while the NAM moves
the front further southward along the NC/VA border. This difference
in location will be a big factor for precipitation during the day on
Wednesday. The more southern solution for the NAM, means a strong
westerly flow is able to form which will keep most of our region dry
during the day while the GFS/Euro solutions would mean our region
could see continued chances for showers. Went middle ground with
Pops and kept mainly chance/low end likely pops for Wednesday.

The big question for Wednesday evening will be how far north the
front is able to move as it returns northward. As the front lifts
northward, a surface low is forecast to form along the boundary as
an upper level shortwave passes overhead. The GFS and Euro are more
progressive with the northward propagation of the front while the
NAM keeps the boundary overhead of our region Wednesday evening. It
seems the differing solutions will mean the difference between an
increased SVR threat and increased flood threat. The GFS and Euro
would mean a bigger SVR threat due to increased CAPE and shear along
the boundary.  The NAM solution on the other hand would mean a
bigger flood threat. Both the 6z and 12Z NAM are highlighting areas
south of I-66 for the potential for rain amounts of 2 to 5 inches in
a 12 hour period. We should have a better idea of the overall threat
for SVR and flood once Wednesday moves into the range of the high-
Res guidance.

[yoda]

Well that escalated quickly on the 18z NAM soundings 

[CAPE]

Snippet from Mount Holly AFD this morning-

Things get potentially more interesting for Wednesday night. A new area of low pressure looks to take shape over the midwestern states along the lingering frontal boundary. This will then deepen as it moves northeast towards eastern PA through Wednesday night. There are still model differences regarding the strength and track of this system but the general trend appears to be towards a stronger system . Both the GEM Reg and especially the GFS depict a robust shortwave driving this system as it eventually takes on a neutral to negative tilt by early Thursday. The system will be accompanied by widespread showers and storms by late Wednesday evening through the overnight and this could actually come through in multiple rounds. And in fact we have concerns for both the potential for severe weather and heavy rainfall with an associated flood/flash flood risk. This is because strengthening low moving right near the area could result in deep layer shear increasing to 40 to 50 knots. In addition both the GFS and GEM depict a strong LLJ at 850 mb advecting in PWATs of around 2 inches with this LLJ also helping to aid in increased low level shear. It is still too early to be confident in exactly how this will evolve as, along with the uncertainty regarding the strength of the system, a potentially limiting factor will be the timing during the overnight during the diurnal min of instability. Even so though, the strong low level warm and moist advection could still result in at least several hundred j/kg of CAPE which may be enough given the strong dynamics and shear.

[Kmlwx]

CIPS has a severe signal in our region and into the NE around the 240hr mark.