May 15-20 Severe Threat

[janetjanet998]

another TOG on the ground in KS

 

where is the watch?

[jojo762]

Multiple tornado warned storms right now across South-central KS with confirmed tornadoes, albeit all are fairly small/weak storms. Some possibility that storms could strengthen as they move eastward into more unstable air. 

Winds are locally backed across this region, and a weak bowing-segment that went through late this morning left behind a nice vorticity pool... At least some small/weak tornado threat should exist for a few hours.

[janetjanet998]

TX AGAIN

EVERE WEATHER STATEMENT  
NATIONAL WEATHER SERVICE SAN ANGELO TX  
440 PM CDT FRI MAY 19 2017  
  
TXC059-083-399-441-192200-  
/O.CON.KSJT.TO.W.0026.000000T0000Z-170519T2200Z/  
CALLAHAN TX-COLEMAN TX-TAYLOR TX-RUNNELS TX-  
440 PM CDT FRI MAY 19 2017  
  
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 500 PM CDT FOR  
SOUTHWESTERN CALLAHAN...NORTHWESTERN COLEMAN...SOUTHEASTERN TAYLOR  
AND NORTHEASTERN RUNNELS COUNTIES...  
      
AT 433 PM CDT, A CONFIRMED TORNADO WAS LOCATED 4 MILES NORTH OF   
CREWS, OR 15 MILES EAST OF WINTERS, MOVING NORTHEAST AT 20 MPH.  
  
HAZARD...DAMAGING TORNADO AND GOLF BALL SIZE HAIL.   
  
SOURCE...WEATHER SPOTTERS CONFIRMED TORNADO.   

[jojo762]

URGENT - IMMEDIATE BROADCAST REQUESTED
   Tornado Watch Number 250
   NWS Storm Prediction Center Norman OK
   440 PM CDT Fri May 19 2017

   The NWS Storm Prediction Center has issued a

   * Tornado Watch for portions of 
     South-central Kansas
     North-central Oklahoma

   * Effective this Friday afternoon and evening from 440 PM until
     1000 PM CDT.

   * Primary threats include...
     A few tornadoes possible
     Scattered large hail and isolated very large hail events to 2
       inches in diameter possible
     Isolated damaging wind gusts to 70 mph possible

   SUMMARY...Thunderstorms are forming over south-central Kansas and
   north-central Oklahoma, in an environment favorable for low-topped
   supercells.  Isolated tornadoes will be possible, along with
   damaging winds and hail in the strongest cells.

[janetjanet998]

Still on ground in tx

EVERE WEATHER STATEMENT  
NATIONAL WEATHER SERVICE SAN ANGELO TX  
448 PM CDT FRI MAY 19 2017  
  
TXC059-083-399-441-192200-  
/O.COR.KSJT.TO.W.0026.000000T0000Z-170519T2200Z/  
CALLAHAN TX-COLEMAN TX-TAYLOR TX-RUNNELS TX-  
448 PM CDT FRI MAY 19 2017  
  
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 500 PM CDT FOR  
SOUTHWESTERN CALLAHAN...NORTHWESTERN COLEMAN...SOUTHEASTERN TAYLOR  
AND NORTHEASTERN RUNNELS COUNTIES...  
      
AT 447 PM CDT, A CONFIRMED TORNADO WAS LOCATED OVER NOVICE, OR 17  
MILES EAST OF WINTERS, MOVING NORTHEAST AT 20 MPH.  
  
HAZARD...DAMAGING TORNADO AND PING PONG BALL SIZE HAIL.   
  
SOURCE...WEATHER SPOTTERS CONFIRMED TORNADO.   

[janetjanet998]

SEVERE WEATHER STATEMENT  
NATIONAL WEATHER SERVICE WICHITA KS  
535 PM CDT FRI MAY 19 2017  
  
KSC095-155-192315-  
/O.CON.KICT.TO.W.0019.000000T0000Z-170519T2315Z/  
RENO KS-KINGMAN KS-  
535 PM CDT FRI MAY 19 2017  
  
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 615 PM CDT FOR  
SOUTHEASTERN RENO AND NORTHEASTERN KINGMAN COUNTIES...  
      
AT 534 PM CDT, A CONFIRMED TORNADO WAS LOCATED 5 MILES   
EAST-SOUTHEAST OF PRETTY PRAIRIE, MOVING NORTHEAST AT 35 MPH.  
  
HAZARD...DAMAGING TORNADO AND QUARTER SIZE HAIL.   
  
SOURCE...WEATHER SPOTTERS CONFIRMED TORNADO.   

[Santa Clause]

That cell has been super impressive, luckily it appears to be splitting major population centers.

[janetjanet998]

REA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE FORT WORTH TX  
530 PM CDT FRI MAY 19 2017  
   
UPDATE  
  
DID A QUICK UPDATE TO ACCOUNT FOR BACKED FLOW AND STRONGER   
SURFACE WINDS THAN PREVIOUSLY FORECAST. MANY LOCATIONS ARE   
GUSTING OVER 30 MPH OUT OF THE SOUTHEAST, WHICH IF NOTHING ELSE   
WILL AT LEAST KEEP THE SEVERE THUNDERSTORM AND TORNADO THREAT   
GOING WITHIN TORNADO WATCH 249 (WHICH REMAINS IN EFFECT UNTIL 11   
PM). THE LATEST INDICATIONS ARE THAT THE SCATTERED CONVECTION JUST  
WEST OF THE REGION WILL EVENTUALLY APPROACH THE I-35 CORRIDOR 8   
TO 10 PM. ANOTHER ROUND OF STORMS WILL BE POSSIBLE AFTER MIDNIGHT   
AS THE STRONGEST FORCING ASSOCIATED WITH A SHORTWAVE DISTURBANCE   
ARRIVES AND A SLOW MOVING COLD FRONT MOVES IN FROM THE NORTHWEST.   
THE SEVERE THREAT SHOULD CONTINUE OVERNIGHT AS THE LOW LEVEL JET   
DEVELOPS, BUT THE THREAT WILL LIKELY BE LOWER DUE TO THE LOSS OF   
DIURNAL INSTABILITY. A LOCALLY HEAVY RAIN THREAT CAN ALSO BE   
EXPECTED OVERNIGHT.  
  

[janetjanet998]

cell now TOR in northern TX

 

also mini storms developing SW of the Metroplex

[SN_Lover]

This is cool! Neat that spc added this. 

[janetjanet998]

two nice couplets now both warned near red river

[janetjanet998]

these 3 appear to be mini sups sometimes trying to get hooks

ULLETIN - IMMEDIATE BROADCAST REQUESTED  
SEVERE THUNDERSTORM WARNING  
NATIONAL WEATHER SERVICE FORT WORTH TX  
658 PM CDT FRI MAY 19 2017  
  
THE NATIONAL WEATHER SERVICE IN FORT WORTH HAS ISSUED A  
  
* SEVERE THUNDERSTORM WARNING FOR...  
  EASTERN HAMILTON COUNTY IN CENTRAL TEXAS...  
  SOUTH CENTRAL ERATH COUNTY IN NORTH CENTRAL TEXAS...  
  NORTHWESTERN CORYELL COUNTY IN CENTRAL TEXAS...  
  EAST CENTRAL COMANCHE COUNTY IN CENTRAL TEXAS...  
  
* UNTIL 745 PM CDT.  
  
* AT 657 PM CDT, A TRIO OF SEVERE THUNDERSTORMS WERE LOCATED 11   
  MILES SOUTHWEST OF HICO, 8 MILES SOUTHEAST OF HAMILTON, AND 12   
  MILES SOUTHEAST OF EVANT. ALL THREE WERE MOVING NORTHEAST AT 25   
  MPH.  

[monsoonman1]

Cell in Morris County, KS has dropped a few tornadoes, including one seemingly in Tallgrass Prairie National Preserve.

[jojo762]

1 hour ago, monsoonman1 said:

Cell in Morris County, KS has dropped a few tornadoes, including one seemingly in Tallgrass Prairie National Preserve.

Had a pretty cool radar presentation... Was producing a tornado when this was captured.

[jojo762]

Pretty active four day period. Including 2 ENH risk days (both verified), a MDT risk day (verified), and a High Risk day (Not verified). Next ten days or so look abnormally boring, things begin to pick back up again in late May/early June possibly.

Lastly, some neat data from the Elk City tornado from one of the CSWR DOWs:

 

[brettjrob]

I feel like it's worth compiling a list of setups that ranged from disappointing to all-out busts for western OK, where the region west of roughly Lawton to Enid was the main focus. I skimmed through my chase logs and came up with these, all of which had at least 10% tor probs for most of that area.

4/1/06 (80/50 TOR watch)
5/6/07
4/7/08 (PDS)
4/25/09
4/26/09 (HIGH, PDS)
5/23/11
4/17/13
5/8/15
5/9/15
4/26/16 (PDS)
5/8/16
5/16/17 (PDS)
5/18/17 (HIGH, PDS)

Some of these are reaching a tad, but the fact remains: the last time we had a real "outbreak" scenario with multiple storms producing serious long-track tornadoes in that region was 2001. There have certainly been serious tornadoes out there, like 11/7/11, 4/14/12 and 5/16/15, but they were all basically single-storm events in OK (sometimes surrounded by many failed storms, like 5/16/15).

And yet:

I think you could find just about every failure mode possible for Plains events among the busts and semi-busts/letdowns out there the last 10-15 years.

[Freshgeek]

26 minutes ago, brettjrob said:

Some of these are reaching a tad, but the fact remains: the last time we had a real "outbreak" scenario with multiple storms producing serious long-track tornadoes in that region was 2001

Are you not counting 05/24/2011? There were at least four cells that day that went on to produce massive tornadoes capable of EF4+ damage, including one EF5.

[Quincy]

There is somewhat of a gap in western Oklahoma in general when it comes to long track and/or intense tornadoes, that dates back to the beginning of reliable records. Maybe population density plays a small role, but adjacent areas of the Texas panhandle, Kansas and Oklahoma have had more such events.

 

[andyhb]

4/27/1912 is probably your benchmark event when it comes to W OK. Don't think anything before or since that has even come close. There's the Snyder tornado in 1905 and the Woodward tornado of course in 1947, but those were mostly singular things.

[brettjrob]

42 minutes ago, Freshgeek said:

Are you not counting 05/24/2011? There were at least four cells that day that went on to produce massive tornadoes capable of EF4+ damage, including one EF5.

The focus that day was mainly east of the area I'm talking about, but point taken. The Canton tornado was pretty far west (though still not in great chase terrain, for those keeping score).

21 minutes ago, andyhb said:

4/27/1912 is probably your benchmark event when it comes to W OK. Don't think anything before or since that has even come close. There's the Snyder tornado in 1905 and the Woodward tornado of course in 1947, but those were mostly singular things.

Yeah, no doubt. I'm not expecting historic outbreaks every few years or anything, and it's not like it would take a 5/24/11 caliber event with multiple EF4-5s (shifted 80-100 mi. W) to qualify as breaking the drought. I'd say 10/9/01 was a perfectly respectable dryline tornado event (regional outbreak) that one would expect to see with some regularity in any similar-size region of the southern Plains. That you can't find anything even matching that for 16 years afterwards is, to me, pretty remarkable. The number of solid multi-storm events in adjacent areas like C OK, C KS, W KS in that post-2001 period is also striking. There have been a handful of eye-catching busts in those areas, too, but not like this.

EDIT: Plotting all reports with path length >1 mi. since 10/10/01, it occurs to me that you might be able to make a similar argument for E KS. I can't remember off the top of my head if they've had a big multi-storm day since 5/8/03. At the same time, I don't remember anywhere near the same number of mega-hype busts there, either.

[DanLarsen34]

15 hours ago, brettjrob said:

The focus that day was mainly east of the area I'm talking about, but point taken. The Canton tornado was pretty far west (though still not in great chase terrain, for those keeping score).

Yeah, no doubt. I'm not expecting historic outbreaks every few years or anything, and it's not like it would take a 5/24/11 caliber event with multiple EF4-5s (shifted 80-100 mi. W) to qualify as breaking the drought. I'd say 10/9/01 was a perfectly respectable dryline tornado event (regional outbreak) that one would expect to see with some regularity in any similar-size region of the southern Plains. That you can't find anything even matching that for 16 years afterwards is, to me, pretty remarkable. The number of solid multi-storm events in adjacent areas like C OK, C KS, W KS in that post-2001 period is also striking. There have been a handful of eye-catching busts in those areas, too, but not like this.

EDIT: Plotting all reports with path length >1 mi. since 10/10/01, it occurs to me that you might be able to make a similar argument for E KS. I can't remember off the top of my head if they've had a big multi-storm day since 5/8/03. At the same time, I don't remember anywhere near the same number of mega-hype busts there, either.

I wonder what accounts for that. Climatologically speaking, those areas should see a good deal of significant tornadoes.

[Chinook]

Does anybody know if tornado damage has been found or surveyed at Greenfield/Geary OK on Thursday? It certainly looked like a pretty obvious rotational signature there.

[jojo762]

Subject to change, but appears we will end up with roughly 108 tornadoes for the May 15-19 period. Feels like it was a bit underwhelming. Didn't really see a memorable day necessarily, and there weren't really any high-end long tracking storms aside from maybe the Elk City supercell, and perhaps the Seiling/Waynoka, OK supercell. Recommend looking up videos for the Seiling tornado, best videos/tornado from the entire sequence imo.

[Misstertwister]

On 5/19/2017 at 9:46 PM, jojo762 said:

Pretty active four day period. Including 2 ENH risk days (both verified), a MDT risk day (verified), and a High Risk day (Not verified). Next ten days or so look abnormally boring, things begin to pick back up again in late May/early June possibly.

Lastly, some neat data from the Elk City tornado from one of the CSWR DOWs:

 

Next week or so does look slow but Friday looks interesting, at least by EHI. Thoughts?

[bjc0303]

9 minutes ago, Misstertwister said:

Next week or so does look slow but Friday looks interesting, at least by EHI. Thoughts?

EHI alone not sufficient. You can max out EHI without having an environment capable of initiating convection. 

Brief lull in severe until Fri/Sat/Sun where we may see some dry line supercell activity. No solid consistency yet, but looks like there will be something.

[jojo762]

50 minutes ago, bjc0303 said:

EHI alone not sufficient. You can max out EHI without having an environment capable of initiating convection. 

Brief lull in severe until Fri/Sat/Sun where we may see some dry line supercell activity. No solid consistency yet, but looks like there will be something.

 

1 hour ago, Misstertwister said:

Next week or so does look slow but Friday looks interesting, at least by EHI. Thoughts?

Yep. EHI is a good measure *only* of conditional storm potential, have to have deep moist convection for it to matter, even so EHI can be misrepresentative of an environment in a plethora of ways. But yeah, boring this next week for the most part... perhaps some potential toward the very end of May into June. In regard to what bjc0303 was mentioning, some hint from the op-GFS of at least a modest trough with SW flow in the May 26-28 time frame, but any other details are nebulous  and TBD. 

Also in regard to the day you are referring too (despite that it is still far out), sure the environment is kinematically (wind speeds with height...shear... SRH, etc) and thermodynamically (lapse rates, moisture, instability, etc) impressive resulting in sky high EHI, but look at forecast soundings.... they show a substantial amount of convective inhibition (CINH). That cap is not breakable if you do not have strong forcing for ascent(which that day does not have, with no noticeable S/W [shortwave] to create lift), and even then so that cap is still fairly substantial even if you do have a moderately strong perturbation, this is why the GFS shows zero convection along the entire dryline in the QPF (precipitation) fields.

[bjc0303]

I will say the GFS has not had much consistency with these features, so these forecasts are very much subject to change (including fcst EML/base temperatures and related inhibition). 

[jojo762]

7 minutes ago, bjc0303 said:

I will say the GFS has not had much consistency with these features, so these forecasts are very much subject to change (including fcst EML/base temperatures and related inhibition). 

Certainly has my interest, at least... any potential southwest flow in late May and into June garners at least some interest. Myriad of factors, as you said, are still up for potential changes. 

[JasonOH]

Has anyone heard anything about surveys from Thursday? I haven't seen anything about the tornadoes on OUN's twitter.

[andyhb]

Longest tracked tornado on record in WI confirmed via MPX, also upgraded to EF3.