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2021 Short/Medium Range Severe Thread


Hoosier
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Thread created just in time lol.  SPC just upped tor probs to 5% in southeast MN, far west WI, and extreme northeast IA.  HRRR has considerably more surface cape than 3km NAM, as it has dews pooling into the upper 50s to near 60 ahead of the surface low, while the 3KM NAM keeps dews lower in the 50s.  The result is cape AOA 1000J/kg on the HRRR and <100J/kg on the NAM.  SPC must be banking on the HRRR working out, as if the NAM ends up being correct tors would be very hard to come by.  I for one am rooting for the HRRR, let's kick off 2021 severe season with a bang.

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13 minutes ago, Indystorm said:

Did not expect svr possibilities that far nw so soon.  NAM seems to be discounting cloud breaks and clearing showing up on satellite as SPC notes.   Could be more interesting than  initially expected for today .

Yep, looks like some sneaky potential in the SE MN/WC WI area. Of course, the first event of the season somehow manages to be out of my after-work range to the north. :rolleyes: If I hauled @** I could reach the MS River by go time, but that and points east are awful chase terrain up there.

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31 minutes ago, Indystorm said:

HRRR progs SiG TOR around 3 in the affected area late this afternoon into the early evening.

It's a little ominous in wanting to slam the strongest cell of the event (apparently a sweet-spot triple point rider) into the southern part of the Twin Cities metro for a couple runs in a row. Warrants close attention.

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2 hours ago, CheeselandSkies said:

It's a little ominous in wanting to slam the strongest cell of the event (apparently a sweet-spot triple point rider) into the southern part of the Twin Cities metro for a couple runs in a row. Warrants close attention.

HRRR has now dropped that idea the last couple hourly runs and now shows everything lining out quickly along the front with no UH >75. Keeps the line intact just barely through MBY by 04Z.

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First Tor warning of the year for this area. 

 

 

 

Quote

 

Tornado Warning


Tornado Warning
MNC037-131-139-102245-
/O.NEW.KMPX.TO.W.0001.210310T2213Z-210310T2245Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Twin Cities/Chanhassen MN
413 PM CST Wed Mar 10 2021

The National Weather Service in the Twin Cities has issued a

* Tornado Warning for...
  Southwestern Dakota County in east central Minnesota...
  Southeastern Scott County in east central Minnesota...
  North central Rice County in south central Minnesota...

* Until 445 PM CST.

* At 413 PM CST, a severe thunderstorm capable of producing a tornado
  was located over Webster, or 10 miles west of Northfield, moving
  northeast at 45 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without
           shelter. Mobile homes will be damaged or destroyed.
           Damage to roofs, windows, and vehicles will occur. Tree
           damage is likely.

* This dangerous storm will be near...
  Lakeville and Farmington around 435 PM CST.
  Apple Valley around 440 PM CST.
  Rosemount around 445 PM CST.

Other locations impacted by this tornadic thunderstorm include Castle
Rock and Lakeville Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4445 9335 4448 9343 4477 9325 4467 9300
TIME...MOT...LOC 2213Z 207DEG 38KT 4450 9336

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

ETA

 

 

 

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  • 2 weeks later...

Anyone have an eye on the cold core severe potential on Tues? Some impressive cold temps aloft right over central IL. Instability doesn't look great but that could improve as we get closer. Even if it doesn't, I could see some tornado potential being possible with low topped supercells. 

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Anyone have an eye on the cold core severe potential on Tues? Some impressive cold temps aloft right over central IL. Instability doesn't look great but that could improve as we get closer. Even if it doesn't, I could see some tornado potential being possible with low topped supercells. 

Has similarities to 12/1/18.


.
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19 minutes ago, Chicago Storm said:


Has similarities to 12/1/18.


.

Definitely thought the same thing. SPC and NWS not too optimistic about the threat but I think at some point there will be a slight risk. 3km nam looks nice. Arc of storms by 18z that moves into central IL through 0z. 

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4 hours ago, CheeselandSkies said:

Day 2 marginal introduced...for the far southern MS valley, lol.

   
..MIDDLE MS VALLEY  
  
SURFACE HEATING WILL REMAIN LIMITED AHEAD OF THE SURFACE LOW ACROSS  
NORTHERN MO INTO WEST-CENTRAL IL AND EASTERN IA. HOWEVER, STEEPENING  
MIDLEVEL LAPSE RATES WILL SUPPORT AT LEAST A COUPLE HUNDRED J/KG  
MUCAPE DURING THE AFTERNOON/EVENING. EFFECTIVE SHEAR AROUND 30-35 KT  
COULD AID IN A FEW ORGANIZED LOW-TOPPED CELLS NEAR THE SURFACE  
LOW/TRIPLE POINT FOR A BRIEF PERIOD. THIS ACTIVITY WILL LIKELY  
REMAIN ELEVATED GIVEN LIMITED HEATING. SOME SMALL HAIL OR GUSTY  
WINDS ARE POSSIBLE, BUT THE OVERALL SEVERE THREAT APPEARS TOO  
LOW/CONDITIONAL AT THIS TIME TO INTRODUCE PROBABILITIES.  

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5 minutes ago, janetjanet998 said:

   
..MIDDLE MS VALLEY  
  
SURFACE HEATING WILL REMAIN LIMITED AHEAD OF THE SURFACE LOW ACROSS  
NORTHERN MO INTO WEST-CENTRAL IL AND EASTERN IA. HOWEVER, STEEPENING  
MIDLEVEL LAPSE RATES WILL SUPPORT AT LEAST A COUPLE HUNDRED J/KG  
MUCAPE DURING THE AFTERNOON/EVENING. EFFECTIVE SHEAR AROUND 30-35 KT  
COULD AID IN A FEW ORGANIZED LOW-TOPPED CELLS NEAR THE SURFACE  
LOW/TRIPLE POINT FOR A BRIEF PERIOD. THIS ACTIVITY WILL LIKELY  
REMAIN ELEVATED GIVEN LIMITED HEATING. SOME SMALL HAIL OR GUSTY  
WINDS ARE POSSIBLE, BUT THE OVERALL SEVERE THREAT APPEARS TOO  
LOW/CONDITIONAL AT THIS TIME TO INTRODUCE PROBABILITIES.  


Yeah, this does not sound anywhere near a 12/1/18 potential. That was a sneaky day but I don't think THIS sneaky...the area of interest was at least in a marginal risk for the Day 2.

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I would imagine they'll bump up to marginal on later outlooks.  It definitely deserves it with pockets of surface cape AOA 500J/kg present ahead of the front in a high shear environment.  Mid-level lapse rates look kinda crappy, barely 7 C/km so it'll be hard getting cape much above that.  Models have been pretty insistent on temps/dews having a hard time cracking 60/mid 50s.  All in all a low-end threat but looks to be enough for a few tors, and worthy of at least a 2% tor risk.   

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9 minutes ago, cyclone77 said:

I would imagine they'll bump up to marginal on later outlooks.  It definitely deserves it with pockets of surface cape AOA 500J/kg present ahead of the front in a high shear environment.  Mid-level lapse rates look kinda crappy, barely 7 C/km so it'll be hard getting cape much above that.  Models have been pretty insistent on temps/dews having a hard time cracking 60/mid 50s.  All in all a low-end threat but looks to be enough for a few tors, and worthy of at least a 2% tor risk.   

Maybe worth it if you're (very) local, not so much if you have a 3-4 hour drive to and from the target area and work at 3 AM the next day (like me). I really need more clear-cut setups unless they're literally right in MBY, and those have been in short supply in this region these last several years.

Of course, the atmosphere tried to gift me Rochelle day in 2015 and I managed to screw that up, too. :rolleyes:

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19 minutes ago, CheeselandSkies said:

Maybe worth it if you're (very) local, not so much if you have a 3-4 hour drive to and from the target area and work at 3 AM the next day (like me). I really need more clear-cut setups unless they're literally right in MBY, and those have been in short supply in this region these last several years.

Of course, the atmosphere tried to gift me Rochelle day in 2015 and I managed to screw that up, too. :rolleyes:

Haha me too.  That day will haunt me forever.  We had chased the first main cell of the day from west of Ottumwa all the way up towards Clinton but missed the tors it finally produced there.  Said screw it and gave up and went to Applebees in Moline lol.  Later on into the meal started hearing about the tornado out by Ashton that went on to hit Fairdale.  That sup passed only about 20 miles east of home, could have just sat home all day and lolly gagged out there late in the afternoon and followed it from there.  :facepalm:

 

dd.jpg

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10 minutes ago, cyclone77 said:

Haha me too.  That day will haunt me forever.  We had chased the first main cell of the day from west of Ottumwa all the way up towards Clinton but missed the tors it finally produced there.  Said screw it and gave up and went to Applebees in Moline lol.  Later on into the meal started hearing about the tornado out by Ashton that went on to hit Fairdale.  That sup passed only about 20 miles east of home, could have just sat home all day and lolly gagged out there late in the afternoon and followed it from there.  :facepalm:

 

dd.jpg

The one "Big Dog" I have been on and it fell into my lap. I was getting some work done on the truck and could see it out the window, so I dropped the jack and took off. Followed it for awhile until it crossed 39 and the road got clogged heavily with other chasers driving like absolute madmen. Decided I had seen enough and getting in an accident wasn't worth any more photos. 

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34 minutes ago, cyclone77 said:

Haha me too.  That day will haunt me forever.  We had chased the first main cell of the day from west of Ottumwa all the way up towards Clinton but missed the tors it finally produced there.  Said screw it and gave up and went to Applebees in Moline lol.  Later on into the meal started hearing about the tornado out by Ashton that went on to hit Fairdale.  That sup passed only about 20 miles east of home, could have just sat home all day and lolly gagged out there late in the afternoon and followed it from there.  :facepalm:

 

dd.jpg

I sat in Forreston (near top center of the map) for awhile that afternoon, then felt like the atmosphere was taking too long to recover from the pre-warm frontal clouds and showers, plus generally low expectations for an early April setup that far north (3/15/16 and 2/28/17 had yet to occur, lol); turned around and went home, arriving just in time to pull up GR Level 3 and watch the debris ball track ~20 some miles from where I'd just been. If I'd stuck it out for just another 20-30 minutes I probably would have clued in on the rapid changes taking place in the lower atmosphere (or if I'd had access to mobile data on the road, which I wouldn't until I jumped on the smartphone bandwagon in 2017).

What is it with May and June being dead in this region after 2016 (apart from 2019, which while the results weren't spectacular there were at least opportunities); with our regional chase "season" consisting of one day way closer to the cold season than seems right (2/28/17 and 12/1/18 being particularly egregious, also 3/28/20 which busted anyway compared to its ceiling) and one random day in the mid-late summer (7/19/18, 8/10/20)?

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Yeah, this does not sound anywhere near a 12/1/18 potential. That was a sneaky day but I don't think THIS sneaky...the area of interest was at least in a marginal risk for the Day 2.

The environment with this potential is really not that far off the environment from that day.

Guidance the past day or so have really slowed things, with most of the potential being across MO/S IA now.


.
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Marginal introduced

 

1354368838_day2otlk_1730(2).gif.4c25e42727dda9714bab31ef7dc03cd1.gif

 

...MO...IA...IL...
   Early day rain and storms should quickly shift east across MO and AR
   along the low-level jet axis. Although the surface low will be
   slowly filling, daytime heating will produce a plume of steep
   low-level lapse rates across much of central MO and extending into
   southwest IA. With 50s F dewpoints and cold air aloft, the result
   will be an uncapped and sufficiently unstable air mass to support
   low-topped cells, including a few supercells. A broken arc of storms
   is expected to form after 18Z over western MO, moving northeastward
   toward southern IA and western IL by 00Z. Veering winds with height
   as well as favorable low-level buoyancy may support a brief tornado,
   along with marginal hail.
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