Monday, October 20, 2025 Squall Line Potential

[weatherwiz]

A vigorous shortwave trough crosses the region late Sunday night and Monday with strong cold front and triple point moving across the region Monday morning. This system will be characterized by a potent 80+ knot mlvl jet streak and 60-70+ knots of bulk shear overspreading the region to go along with steeping mid-level lapse rates associated with cooling temperatures aloft. Out ahead of the shortwave trough, a strong southerly flow will develop pumping in an unseasonably moist low-level air mass. 

The combination of an unseasonably moist low-level airmass combined with modestly steep mid-level lapse rates (~ 6.5 C/KM) should yield upwards of 250-500 J/KG of MLCAPE. Bulk shear values in excess of 60-70 knots combined with vigorous forcing will likely promote a squall line consisting of heavy rain, thunder/lightning, and strong-to-damaging wind gusts along the leading edge, moving across the region early-to-late morning Monday. Forecast soundings exhibit enough low-level turning, particularly in the vicinity of the triple point to warrant potential for a few embedded QLCS tornadoes. 

[Cyclone-68]

This is a mortal lock because I won’t be around to enjoy it 

[Damage In Tolland]

Reminds me of the Oct 3, 1979 Windsor Locks setup 

[CoastalWx]

Meh

[Damage In Tolland]

Looks pretty wild Monday AM

[CoastalWx]

Maybe right on S coast can watch. Looks meh outside that.

[Torch Tiger]

Never looked like much

[Damage In Tolland]

Damage?

[Torch Tiger]

Looks light

Could be a rumble or two
of thunder with strongest shower activity but unfavorable time of
day and shallow progged instability should limit this. Flow fields
are pretty strong, with winds around 925 mb around 50-55 kt, but
strongest jetcore is locked in a shallow inversion. Pattern looks
similar to what we tend to find in late-Fall and the early-Spring
with a strongly-forced line of downpours with brief gusty winds but
limited severe weather potential.

[Damage In Tolland]

Yup .. damage 

[Damage In Tolland]

The shortwave trough arrives along with a strong surface front early
Monday morning, and moves quickly offshore by mid Monday afternoon.
Guidance is in rather good agreement on the timing of the line of
heavy rain or Fine Line.  The Fine Line should be approaching
western MA/CT between 5-7 am and arriving at the I-95 corridor
between 8-11 am. The line will then be moving offshore, likely
by 1-2 pm in the afternoon. Although Fine Line will be moving
rather quickly, it will pack a punch as it moves through and
create disruptions to the morning commute. PWATS ahead of the
line will be surging to near 1.5 inches, which, combined with
the strong forcing from the shortwave, will likely result in
rain rates exceeding 1-2 inches per hour. Strong to possibly
damaging winds may also accompany the line as low-level winds
around 2kft will be approaching 50-60mph. 

[CoastalWx]

Fine lines typically don’t produce damage. You’ll need a rogue strong cell either within the line or just ahead of it to cause it. Too bad it wasn’t 6 hrs later.

[Torch Tiger]

fine line...that must be inducted into the fraud 7 or whatever  

Right up there with the D5 cheerfully optimistic anafrontal 3-6" for Christmas day

i'm not working tomorrow so expecting a dud, but hopefully DIT and Ineedsnow get some damage

[CoastalWx]

4 hours ago, CoastalWx said:

Fine lines typically don’t produce damage. You’ll need a rogue strong cell either within the line or just ahead of it to cause it. Too bad it wasn’t 6 hrs later.

18z hrrr actually shows this. Bigguns within the line.

[Damage In Tolland]

Let’s spin some trees down onto lines 

[Damage In Tolland]

HRRR has some big rips

 

[CoastalWx]

Ahh the clowns 

[Chrisrotary12]

Still waiting for my 10a golf tournament in Dover, NH to be cancelled. Otherwise it’s going to be wild.

[Damage In Tolland]

8 minutes ago, Chrisrotary12 said:

Still waiting for my 10a golf tournament in Dover, NH to be cancelled. Otherwise it’s going to be wild.

Clubs ripped out of bags and thrown into pond?

[metagraphica]

1 hour ago, Damage In Tolland said:

HRRR has some big rips

 

30-40 out of the SE in my hood and I'll lose power. Again.