Wednesday, September 21, 2022 NOCTURNAL Severe Threat (or Technically 09.22.2022)

[weatherwiz]

A vigorous shortwave trough is expected to move across the Great Lakes region Wednesday and across New England early Thursday. Ahead of this trough a warm front lifts across the Northeast ushering in higher theta-e air characterized by dewpoints climbing well into the 60's. This will help contribute to an unstable low-level airmass across the region. Very strong jet dynamics will also overspread the region with a 50-60+ knots of wind at 500mb along with a jet streak of 80-90 knots placing the region in the right front quadrant. This will help contribute to bulk shear values in the 40-60 knot range (and even higher off to the West). 

A plume of very steep mid-level lapse rates will move across the region during the afternoon, however, it appears this plume will move off the coast and weaken prior to the overnight period (boooooooooooooooo). Regardless mid-level lapse rates may be in the 6-6.5 C/KM during the overnight. Despite being overnight these lapse rates combined high low-level theta-e air should contribute to sufficient instability to aid in thunderstorm develop and aid in the sustaining of thunderstorms across the region. 

All in all the potential exists for a fairly robust and widespread severe weather event stretching from New York/Pennsylvania during the daytime and across New England during the late evening and overnight. Damaging winds will be the greatest concern, however, hail would also be a possibility and there could even be the potential for a few QLCS embedded tornadoes. 

The biggest question mark right now is there may be a bit of a disconnect between the upper-level trough and sfc cold front. 

[Damage In Tolland]

Damage 

[weatherwiz]

At least we'll be able to muster some elevated convection with hopefully a good light show  

[weatherwiz]

Actually timing slowed down to the point to where eastern sections may have a chance for some svr Thursday

[Torch Tiger]

Yeah timing is definitely slower than a few days ago.  Looks like an AM event here, maybe early aftn for S areas

[Brewbeer]

thunder

[Damage In Tolland]

Danger ahead?

[weatherwiz]

Of course I go to Branford today and where I am in Springfield is about to get NAILED   

[Cold Miser]

It's darker out now than when I left for work at 6am. 

Raining buckets...

Raining Cats and Dogs...

Coming Down in Sheets...

[Insert favorite, heavy rain idiom/ expression here]

[Ginx snewx]

Danger Will Robinson? NBC10 model from Aaron Perry

[weatherwiz]

Thunder!!!

[weatherwiz]

Might be some small hail over West Haven per CC

[Modfan2]

Nice line in E Ct

[Hoth]

Ba-boom! Some excellent CGs in downtown New Haven this morning. 

[Torch Tiger]

Pretty good +cg's

[ct_yankee]

11 minutes ago, Hoth said:

Ba-boom! Some excellent CGs in downtown New Haven this morning. 

Indeed there were... Woke me right the (expletive deleted) up instantly, can tell you that. Every now and then we seem to get these morning surprises, and they are often unsually strong, especially considering the general lack of instability and this hour of the day.... Very loud and annoying if one is still in bed.

 

 

[Whineminster]

Crazy out there

[weatherwiz]

8 minutes ago, ct_yankee said:

Indeed there were... Woke me right the (expletive deleted) up instantly, can tell you that. Every now and then we seem to get these morning surprises, and they are often unsually strong, especially considering the general lack of instability and this hour of the day.... Very loud and annoying if one is still in bed.

 

 

Dynamics FTW 

[Cyclone-68]

Thundering here 

[dendrite]

Best rain missing north and south again. Should be a decent drink despite the screwgie though. 

[Damage In Tolland]

Hopefully damage is Regional with this today .

The main severe weather threat will roughly be from 9 am to 1
pm across western MA/CT and late morning through about 4 pm
across eastern MA/RI. This is when the associated cold front and
its associated strong forcing arrives. Quite the impressive
dynamics will be present with effective shear of 45-55 knots and
500-1000 J/KG of Cape. These type of events are challenging to
forecast because a small change in Cape can make the difference
between numerous severe thunderstorms vs. not much of anything.
Some of the latest machine learning probabilities have
increased the potential for severe weather over the past 24
hours. In fact...the latest SPC SCRAM is very aggressive in
showing high probs of a line of showers and thunderstorms with
the potential for strong to damaging wind gusts. Given the
strong dynamics and fully leafed trees there is concern for
pockets of wind damage and power outages. While this potential
exists across the entire region; 

[weatherwiz]

Three things to focus on:

1) How steep do 2-6km lapse rates becoming

2) Pretty strong LLJ across eastern sections. 30-40 knots at 925mb. 

3) DCAPE values 600-800 J/KG 

Thinking we see some wind damage for sure across eastern areas

[bristolri_wx]

Looks like most of RI missing out on the good stuff in first batch.  Hopefully we get hit with the second one!  Enjoy round one MA, NH, and ME!

[CoastalWx]

Nice little morning line. 

[bristolri_wx]

That second line looks juicy for RI and SE MA on the 12z HRRR.

[MarkO]

6" on the nose for the month. Not sure why we're still in a moderate drought. I've had a little over a foot since June 1st. That's averages about 3.25"/month.

[Damage In Tolland]

9 minutes ago, CoastalWx said:

Nice little morning wood.

Tight undies?

[Damage In Tolland]

2nd line looks like garbage 

[dendrite]

2nd line looking like a good drink up here. 

[dryslot]

The first one has not been bad here so far, Just about thru before line 2 moves in, Standing water everywhere.