Jump to content
  • Member Statistics

    Total Members
    Most Online
    Newest Member

2021 Short/Medium Range Severe Thread


Recommended Posts

EC dropping the big one with a tornado watch locally quite early:

Tornado Watch

Issued at 12:03 Tuesday 14 September 2021

Conditions are favourable for the development of severe thunderstorms which may produce tornadoes.

Large hail up to ping pong ball size
Wind gusts up to 120 km/h
Heavy downpours

Timing: This afternoon and evening.

Discussion: A line of severe thunderstorms is expected to move eastward across the regions this afternoon and into the evening. Some of these storms will likely contain tornadoes.


I think they got spooked from last Tuesday with the largest tornado in Ontario history occurring near Kingsbridge-Lucknow (1300 meters wide). For comparison the violent tornadoes of May 31 1985 here were 200 and 600 meters respectively!!

This tornado watch is the largest geographically I've seen too:


Largest Tornado Watch Coverage ON Sep 14 2021.jpg

Link to comment
Share on other sites

1 hour ago, StormfanaticInd said:

This fall is show signs of being active severe weather wise. Something we haven't seen in a while 

Not sure why you were weenied but I agree! The lightning tonight alone would’ve been prolific for any mid-July storm, let alone with astronomical fall a week away! 

  • Like 1
Link to comment
Share on other sites

The 2nd Tuesday in a row of a tornado warning for Grey-Bruce/Huron county and this time I saw the rotation right at home! In the beginning I wasn't sure if I saw a funnel or just scud but I could briefly see the rotation just like I did in the Plains. It lined up with reports of rotating wall cloud north of Walkerton moving east. Then a new couplet must have formed to the south and OPP in Mount Forest reported a touchdown 30 minutes later around 7:30 pm. I had a lot more lightning and rain than last Tues. No hail for me. 4 waves of storms this evening and I'm up to an astounding 14 storms for the year :wub: This has been so far the most active September I've ever seen for storms and others concur. With all these tornado warnings this is getting insane :twister:.
  • Like 1
Link to comment
Share on other sites

Up to 5% tor at the 13Z. This strong FROPA was on my radar (so to speak) at longer ranges but I admit I kind of tuned it out once it got into Day 4-8 range and SPC said the strongest winds aloft and support for ascent would lag behind the warm sector. I haven't looked at any models myself yet so I can't say if that's changed in some fashion or if they're just hedging their bets.

Link to comment
Share on other sites

17 minutes ago, Chicago Storm said:

they're not an intelligent bunch there.

Still way better than me at severe weather forecasting (I should hope so because they get paid to do it), but even I find myself scratching my head at more and more of their calls in recent years. When and why did they go so far downhill? Just anecdotally (not looking at any actual verification stats, which will probably prove me wrong, lol), seems like they were better in the 2000s/early 2010s despite the advances in modeling that have been made since then.

Link to comment
Share on other sites

  • 3 weeks later...


Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1258 AM CDT Sun Oct 10 2021

   Valid 111200Z - 121200Z


   Strong/isolated severe storms -- including potential for hail,
   locally damaging winds, and a couple of tornadoes -- are expected to
   spread from the Mid Mississippi Valley region early,
   north-northeastward into the Upper Great Lakes through the
   evening/overnight hours Monday and into early Tuesday.

   An upper trough digging south-southeastward across California and
   the Great Basin Monday will evolve into a closed low, which is
   expected deepen and turn eastward overnight reaching the
   southwestern Utah vicinity Tuesday morning.  Ahead of this system, a
   negatively tilted short-wave trough will be shifting northeastward
   across the Lower Missouri and Mid Mississippi Valleys during the
   day, before crossing the Upper Great Lakes region overnight. 
   Meanwhile, ridging will remain in place -- aligned roughly along the

   At the surface, a cold front associated with the western U.S. trough
   will sweep across the Great Basin and into the Four Corners states. 
   Meanwhile, a cold front shifting eastward out of the southern Plains
   toward the Mississippi Valley will weaken with time, while an
   associated/weak frontal low advances northeastward from Missouri to
   Wisconsin/Upper Michigan through the period.

   ...Mid Mississippi Valley northward into the Upper Great Lakes...
   Showers and scattered thunderstorms will likely be ongoing at the
   start of the period from western Illinois/Missouri
   south-southwestward to southeastern Texas, ahead of an advancing
   cold front.  A couple of stronger storms ongoing early could pose
   local risk for severe weather.  After a few hours of local/limited
   risk, diurnal heating through late morning and into the afternoon
   will permit sufficient destabilization to allow gradual
   reintensification/redevelopment of storms, from Illinois to the
   Mississippi Delta region, then spreading northward and northeastward
   through the afternoon.  Though flow aloft will remain largely
   south-southwesterly/unidirectional, sufficient speed shear combined
   with weak veering through the lowest 1 km or so suggests that
   locally severe/rotating storms will evolve, with threat for damaging
   wind gusts, along with some hail risk and potential for a couple of
   tornadoes across a relatively broad geographic region.

   A bit more uncertainty exists with northward extent, and into the
   evening hours, into the Great Lakes region.  While ascent will
   spread across this region supporting a continuation of convection
   through the evening and into the overnight hours, less substantial
   instability -- diminishing further in tandem with diurnal cooling --
   suggests that severe risk will wane gradually from late evening

   ..Goss.. 10/10/2021
Link to comment
Share on other sites

Tomorrow is kinda interesting.


Rapidly progressive triple point could support some highly sheared, relatively low topped supercells with a hail and brief tornado threat. I have an exam at 6:30 so I will not be chasing.

Would expect supercells to be very long and quite skinny based on relatively weak directional shear but exceptional speed shear. Interested to see how that ages.

Link to comment
Share on other sites

4 hours ago, hlcater said:

Tomorrow is kinda interesting.


Rapidly progressive triple point could support some highly sheared, relatively low topped supercells with a hail and brief tornado threat. I have an exam at 6:30 so I will not be chasing.

Would expect supercells to be very long and quite skinny based on relatively weak directional shear but exceptional speed shear. Interested to see how that ages.

Meh, threat (such as it is) shifted too far away to be of interest for me. On the initial day 2 outlook the 2% covered most of the southern 1/2 of WI.

Link to comment
Share on other sites

18 hours ago, StormfanaticInd said:

Friday is kinda sneaky but I see you.:ph34r:

All the ingredients to the potential for widespread moderate to
heavy rain and isolated severe thunderstorms on Friday as a cold
front slides southeast across central Indiana Friday and Friday
evening courtesy of an approaching sharp upper trough and surface
high pressure over the Rockies and High Plains.

Modest to moderate low level 35 knot jet pointing in from western
Kentucky will bring in precipitable water amounts to the 99th
percentile for this time of year. This will combine with strong deep
layer shear of over 50 knots and low level shear near 50 knots to
support the potential of isolated damaging winds despite only weak
instability. 115 plus knot upper level jet streak lifting northeast
around the base of the trough over northwestern Indiana or
northeastern Illinois late Friday supports moderate to heavy rain.
Thus, 90 plus percent PoPs look good for Friday with rain moving
east into Ohio overnight Friday night and Saturday morning. Look for
rainfall of half an inch to over an inch over most or all locations
Friday and Friday night.
  • Like 1
  • Weenie 2
Link to comment
Share on other sites

Already seeing a few checkmarks starting to be ticked off in terms of a fall severe wx potential early next week across recent guidance. Not sure how far north/east it will extend, but it seems there could be a chance for an anomalously large warm sector to exist ahead of whatever ejects eastward from a developing longwave trough in the west. Obviously a lot that could go wrong as with any 8+ day prog, but seeing that moisture available along with a very strong Pacific jet streak making landfall has my eyebrows perked up a bit.

  • Like 6
  • Sad 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...