Wednesday, May 26, 2021 Convective/Severe Weather Potential

[weatherwiz]

1 minute ago, Henry's Weather said:

How does this compare to that August threat last summer? I drove all the way out to Poughkeepsie for that one.

Overall that was a pretty different set up. 

[Henry's Weather]

6 minutes ago, weatherwiz said:

Overall that was a pretty different set up. 

Hopeful we get into the action. Having lived on the coast for most of my life, I've been desensitized by the marine layer crushing my hopes and dreams, but that extra 25 miles west might help!

[WxWatcher007]

18 minutes ago, weatherwiz said:

Pretty impressive environment and CAMs are showing convection around that environment at the time...which would likely be discrete too given the greater forcing still pretty far west.

I don’t really consider myself particularly knowledgeable when it comes to severe compared to others, but when I see 3km CAPE and low level helicity like that line up, I sit up. Obviously there’s a lot more that goes into it, but tomorrow looks interesting from a potential standpoint.

[CoastalWx]

Seems like the stuff late aftn is more along a srfc trough that could hang convection up in NY state and maybe into VT and NH (possible ext NE MA?) Then maybe stuff gets into NW CT from better forcing/cold front after 22-23z. I don't see much hope east of BDL-ORH/LWM other than a flash and a boom. The models still don't agree with timing, so if it is a bit faster, the environment near those places I mentioned is actually pretty good if we can utilize the CAPE/Shear.

[CoastalWx]

Just now, WxWatcher007 said:

I don’t really consider myself particularly knowledgeable when it comes to severe compared to others, but when I see 3km CAPE and low level helicity like that line up, I sit up. Obviously there’s a lot more that goes into it, but tomorrow looks interesting from a potential standpoint.

Yeah the environment in some areas is quite good. The shear at 700-500 doesn't really get going until after 22z or so. 

[weatherwiz]

4 minutes ago, WxWatcher007 said:

I don’t really consider myself particularly knowledgeable when it comes to severe compared to others, but when I see 3km CAPE and low level helicity like that line up, I sit up. Obviously there’s a lot more that goes into it, but tomorrow looks interesting from a potential standpoint.

Agreed!

3 minutes ago, CoastalWx said:

Seems like the stuff late aftn is more along a srfc trough that could hang convection up in NY state and maybe into VT and NH (possible ext NE MA?) Then maybe stuff gets into NW CT from better forcing/cold front after 22-23z. I don't see much hope east of BDL-ORH/LWM other than a flash and a boom. The models still don't agree with timing, so if it is a bit faster, the environment near those places I mentioned is actually pretty good if we can utilize the CAPE/Shear.

Pretty impressive sfc trough actually off to our West. That will definitely be the focus point for more scattered-t-numerous convection. There is a bit of a cap farther east up around 10-15K but alot of the shear and instability is below that anyways. I do like the signal for some discrete stuff late afternoon out this way.

[Henry's Weather]

Severe Threat...
Many of the criteria we look for with regard to severe weather
development in the region is forecast to be in place tomorrow,
though as typical, some of the signals are not as clear. So I
don`t believe it will be an over the top block buster event, but
it will be busy for a few hours late afternoon into the evening.
On the plus side, we`ll definitely have enough surface
instability with CAPE values expected to be 1000-1500 J/kg
across the interior by early afternoon. Thank you temperatures
around 90F and dewpoints in the mid 60s F. Conflicting guidance
from the GFS and NAM as the NAM suggests a weak EML tomorrow
with decent mid-level lapse rates. GFS is much weaker. 0-6km
shear is progged to be around 35kt, so it`s enough to help get
convection organized, but on the lower end of it being in a
sweet spot. Model soundings show weak capping across the area
which will help to keep convection squashed until the upper
level trough gets closer and helps to erode that cap. After
which time we should see rapid convective development. Looking
at various SPC parameters from SREF and HREF, I see signals in
the Supercell Composite and even the SigTor parameter. Noted the
12z HREF shows decent updraft helicity signals, especially in
the 20z-02z time range, suggestive of the potential for
rotating storms. SPC has a 5% risk for a tornado across the
western third of Massachusetts, and I have no reason to argue
with that.  As typical this time of year, the southwest winds
will advect a slightly cooler and definitely more stable airmass
across the southeast portion of the forecast area. So it looks
like the primary severe threat area is from LWM to ORH to HFD
and points west. Some question as to the timing, as the various
hi-res models to differ by several hours as to when the
convection will develop and move into our region. Best estimate
at this point is that 4-8pm will be the peak time of activity
for us, though some convection may start as early as 2pm in the
Berkshires. Given the stable airmass in southeastern areas, and
the fact that it will be after sunset once it reaches far
eastern areas, thinking that convection will go elevated and
quickly weaken, but showers and a few rumbles of thunder may
still continue across SE MA, Cape and Islands until after
midnight. Took a blend of models for the hourly timing of the
PoPs. Kept the mention of gusty winds with t-storms during the
evening. Can`t rule out some hail with stronger storms, but that
seems to be a lower chance.

[weatherwiz]

that's a damn well written discussion!

[weatherwiz]

where do you get the HREF beyond 24-hours? 

edit:

the TOR/WIND/HAIL probs only go to 24-hours.

[Cyclone-68]

“Thank you temperatures”?  Am I missing context somewhere? Lol 

edit: “Whoosh!” to me

[Henry's Weather]

1 minute ago, Cyclone-68 said:

“Thank you temperatures”?  Am I missing context somewhere? Lol 

Dry humor, thanking the temps and dews for this severe threat

[weatherwiz]

1 minute ago, Cyclone-68 said:

“Thank you temperatures”?  Am I missing context somewhere? Lol 

"Thank you temperatures and dewpoints" for the 1000-1500 SBCAPE values...though SBCAPE should probably be between 1500-2500. they may have meant to say MLCAPE between 1000-1500

[RUNNAWAYICEBERG]

This will fizzle. 

[Damage In Tolland]

44 minutes ago, RUNNAWAYICEBERG said:

This will fizzle. 

Agreed. Most towns see nothing except maybe NW CT. 

[DavisStraight]

4 hours ago, Modfan2 said:

Some nice Hills with  awest view on  Rt 31 in Charlton near the old Dresser Hill Ice cream stand,  or further south in Dudley Ma overlooking NE CT

Great spot I go to for severe when Im home, I live 5 miles away. Also a great place when we get blizzards, the snow just blows around and piles up there. In 92 the drifts up there were incredible, we got stuck with my brother in laws 4 wheel drive truck, the drifts were higher than the bottom of the doors.

[weatherwiz]

Greatest potential tomorrow looks to exist across Warren, Saratoga, and Washington Counties in NY into Addison and Rutland Counties in Vermont. I think there could be a small area of enhanced risk for this area.

[Modfan2]

2 hours ago, DavisStraight said:

Great spot I go to for severe when Im home, I live 5 miles away. Also a great place when we get blizzards, the snow just blows around and piles up there. In 92 the drifts up there were incredible, we got stuck with my brother in laws 4 wheel drive truck, the drifts were higher than the bottom of the doors.

Yeah, there and the water tower On 31 in Dudley provided some great views

[RUNNAWAYICEBERG]

3 hours ago, Damage In Tolland said:

Agreed. Most towns see nothing except maybe NW CT. 

They’ll be some isolated storms esp out west but they’ll fizzle as they traverse the state. 

[Cyclone-68]

Sadly this thread really withered on the vine 

[Henry's Weather]

Kinda like this threat

[weatherwiz]

29 minutes ago, Cyclone-68 said:

Sadly this thread really withered on the vine 

Trying to bang out as much work as possible. 

The CAMs are still a bit all over the place but they do agree that there definitely will be scattered convection...and of course greatest coverage across NY/PA into VT. Still a question as to whether we see any discrete storms ahead of the broken line which is where some of the divergence occurs. The environment still looks pretty favorable...just a matter of being able to utilize it

[Cyclone-68]

2 minutes ago, weatherwiz said:

Trying to bang out as much work as possible. 

The CAMs are still a bit all over the place but they do agree that there definitely will be scattered convection...and of course greatest coverage across NY/PA into VT. Still a question as to whether we see any discrete storms ahead of the broken line which is where some of the divergence occurs. The environment still looks pretty favorable...just a matter of being able to utilize it

Well I hope you at least get something interesting 

[Chrisrotary12]

As expected....most of us are likely 25-50 miles too far east and south.

[CT Valley Snowman]

Mitch will do well as usual.  

[Henry's Weather]

So did the EML plume move out too quickly?

[Typhoon Tip]

Fwiw -

https://www.spc.noaa.gov/products/md/md0745.html

[weatherwiz]

10 minutes ago, Henry's Weather said:

So did the EML plume move out too quickly?

it didn't really materialize as it looked a few days ago...very weak/non-existent 

[klw]

I have got myself one of those severe thunderstorm watch thingys I have heard speak of:

https://forecast.weather.gov/showsigwx.php?warnzone=VTZ012&warncounty=VTC027&firewxzone=VTZ012&local_place1=West Norwich VT&product1=Severe+Thunderstorm+Watch&lat=43.7543&lon=-72.3728#.YK5_HqhKhPY

[Typhoon Tip]

It is only just the 1pm hour but ..heh, the timing is just off by that much ...

We may see propagation mechanics come east this evening ( meaning east of the Berkshires ...etc..), but that's contingent upon how organized the upstream activity gets. If it stays small clustered and discrete is may not pool outflow with W-E momentum ... 

Lapse rates are so so, and I think if one bothered to look at severe events ... they tend to scatter plot denser in the side of the graph with steeper lapse rates.  Granted, we don't normally get >1500 CAPEs cooked up around here ...so with some synoptic forcing with a mid level wind acceleration passing astride to the N...this may help/offset.   Not sure -

[weatherwiz]

6 minutes ago, Typhoon Tip said:

It is only just the 1pm hour but ..heh, the timing is just off by that much ...

We may see propagation mechanics come east this evening ( meaning east of the Berkshires ...etc..), but that's contingent upon how organized the upstream activity gets. If it stays small clustered and discrete is may not pool outflow with W-E momentum ... 

Lapse rates are so so, and I think if one bothered to look at severe events ... they tend to scatter plot denser in the side of the graph with steeper lapse rates.  Granted, we don't normally get >1500 CAPEs cooked up around here ...so with some synoptic forcing with a mid level wind acceleration passing astride to the N...this may help/offset.   Not sure -

It will be interesting to see if an increasing LLJ and llvl moisture into the evening will help keep storms going through western sections. But strongly agreed...alot will depend on how organized activity becomes upstream