Significant Severe Weather Event Possible for NNE on July 14 into July 15, 2026

[All Wet]

4 hours ago, weatherwiz said:

Portland may get absolutely drilled. 

Do you have a sense of the time frame for Portland to get "drilled"?   Thinking of clearing out my (non-existant) Y2K bunker...

[weatherwiz]

1 minute ago, All Wet said:

Do you have a sense of the time frame for Portland to get "drilled"?   Thinking of clearing out my (non-existant) Y2K bunker...

There may be two rounds of storms

1) During the evening (7-11 PM) 

2) Overnight (1-3 AM)

Certainly may have to watch for some discrete storms to pop too with that time frame being after 5-6 PM...something to definitely watch for in terms of tornado potential, though potential for these discrete storms early may be more northwest of Portland. I know Portland is outside the enhanced and may be a bit far southwest from the greatest potential but its a damn impressive environment there well into the overnight 

[Chrisrotary12]

2 hours ago, CoastalWx said:

Last winter as in this past winter?? This past winter was great.

For you. Good pack retention though. 
Wish we weren’t capped down here. Top of My. Washington anyone?

[vortex95]

3 hours ago, Cyclone-68 said:

Sept 1821 redux for the north?

https://en.wikipedia.org/wiki/September_1821_New_England_tornado_outbreak

Summaries I made using data from The Tornado Project.
 

[Cyclone-68]

6 minutes ago, vortex95 said:

Summaries I made using data from The Tornado Project.
 

That would have been one hell of a day in the modern age 

[vortex95]

I like what I see. Typically, set ups this potent in New England only occur every 10-15 years or so, going by our most sig tor events/outbreaks.  This qualifies as one IMHO, and it has been 15 years since 6/1/11.

Large-scale, this is not simply NW flow ring of fire event like we had on 7/1.  There is a very strong 500 low over central Quebec w/ a center that gets as low as 543 dm, which is quite impressive for July.

This is *true* NW flow, the best kind for the big svr here.  EML solid up to 8 C/km.

Timing looks absolute best for srn Quebec, but NNE should do very well.

Noted CAPE fcst as high as 4100 on HRRR near YUL Tue aftn and 0-6km shear is more than enough for mean supercells.  It is not as high as it was on 6/18, but we were severely lacking in CAPE and there was no EML, so things are more than compensated here for meaty storms and "Scott spinners."


A few things of note that remind me of 7/10/1989.

1) Very strong WAA prior to the event,  Look at the 12z NAM 1000-500 thk 14/12z to 15/00z for BOS, it jumps from 574 to 584!
2) I attached the 12z NAM valid 15/00z.  Look at the orientation of the very high thk, a W-E axis.  This is exactly how it looked on 7/10/1989, except the axis was about 100 mi farther S.   For that event, it was capped from just S of NYC and S.  So where SPC has the sharp cut off of storms in central New England makes sense 100%.


If I had to find a negative, the 925 mb winds and 0-1 km shear could be higher, at least during the daylight hours, but by 00z, it is more than enough low-level shear for spinners.  However, diurnal stabilization of the BL may limit solid spinners potential in New England.  But the 18z HRRR is still showing small areas over 200 0-3 km CAPE 00/01z across far NNE, which is more than enough for solid low-level stretching and thus spinners. 

Historically, it is very rare for New England to get sig tor after dark (F2/EF2+).

One thing that is almost certain, unreal LTG shows coming for ME/NH/VT Tue evening/overnight. better than event on 7/1.  EMLs "like" to do that!

The fact SPC has a hatched area for tors is not that common in New England, *and* wind/hail are also hatched for the full gamut of a big svr event!

Updraft helicity swaths are nasty on the HRRR, again, rare to be this intense here.  SCP and SIGTOR parameters are about as high as you will ever see them in the NEUS.

Interesting the storms at first look more linear during the day on the HRRR, but become somewhat more discrete by sunset.  This is likely due to the improving shear profiles at low-levels, so tor risk appears good at this later time. 

Really not much more to say.  Slicing and dicing the models down at this point is not that much use.  This is a high-end set up.  Everything is there for a big event.  Intense tstms are a virtual guarantee, just the question is the extent of the spinners overall in srn Quebec and NNE.
 

 

[tamarack]

Forgot this thread and posted the info below on the Ju-ply one:

 

Afternoon AFD from GYX.  Tomorrow evening might get interesting.  Our place is on/near the boundary between levels 2/5 and 3/5.  I can't recall ever being in a 3/5 area.

Now to the increasing threat for severe weather, which again
could be potentially significant. An Enhanced Risk (Level 3/5)
of Severe Weather is in place for northern NH and the western ME
mountains,a Slight Risk (Level 2/5) for central NH and the
Maine interior, and a Marginal Risk (Level 1/5) for coastal ME
and approaching southern NH.

A potent 500mb shortwave will cross Quebec in the afternoon and
evening, with its associated cold front approaching the
International Border from the northwest early Tuesday evening.
Increasing forced ascent, significant height falls, and
strengthening wind fields aloft will set the stage for severe
thunderstorms to develop with the hot and humid air mass in place,
further enhanced by an elevated mixed layer that will steepen lapse
rates aloft.

Today`s 12Z model suite, including CAMs, continue to show deep
layer shear of 50-60 kt, MUCAPE in the 2000-2500 J/kg range, and
high values of DCAPE (800-1000 J/kg) brought on by some dry
air/high dewpoint depressions in the low levels. This supports
damaging wind gusts, and given the parameters, there`s certainly
potential for these to be significant on the order of 75+ mph.
In addition, the instability profiles and steep mid-level lapse
rates on forecast soundings depict large hail could be to the
size of golf balls or even larger. There is also enough
directional shear to support a tornado threat with mean 0-1km
SRH of 100-200 m^2/s^2. These hazards are all possible within
discrete or semi-discrete storm mode, but the primary hazard
will become damaging winds when the dominant mode becomes more
linear, although a tornado within the line(s) will remain
possible.

For timing: there`s strong consensus among the CAMs with
multiple clusters or semi-discrete developing across southern
Quebec in the late afternoon to early evening with rapid upscale
growth in coverage and intensity as storms approach northern NH
and northwestern ME in the 6pm to 8pm time frame. Storms are
expected to quickly progress to the south the rest of the
evening into the early overnight hours. However, it should be
noted there are hints of isolated discrete cells developing in
the 4pm to 6pm timeframe that may approach from the north. Based
on CAM solutions, the threat for severe weather should diminish
after 2 AM, but some development of showers and a few storms is
possible overnight.

This is not a yearly, typical threat of severe storms, and it
becomes even more dangerous as the threat continues after dark. It
is highly advised to have multiple ways to receive warnings,
especially ones that will wake you up with the threat continuing
into the late evening and early overnight hours. The highest risk
areas also include many popular camping and recreation areas,
which make those who are outdoors extremely vulnerable to
falling trees.

[vortex95]

Not that many sig tor (F2/EF2+) in NNE on record.  Attached is a list of the farthest N ones. 
Any tor documented close to the Canadian border outside the CAR area are rare.  Only one
since 1975 I could find is this one.

ME    MAY 23, 1984    1620    0k   0inj   15y  0.3m  F1
SOMERSET - Homes were damaged and a barn lifted and
thrown in Jackman.