Mid to Late May 2019 Severe Threats

[Radtechwxman]

It's legit. Saw someone share a screenshot from nws chat confirming high risk upgrade at 06z outlook. But can't share the image

[SmokeEater]

It's legit. Saw someone share a screenshot from nws chat confirming high risk upgrade at 06z outlook. But can't share the image

Yup, saw it firsthand. Wasn't gonna put it out yet, but since you did I'll confirm, lol. Parts of W TX, TX Panhandle and W OK.

Sent from my SM-G973U using Tapatalk

[MUWX]

Broyles? 

[1900hurricane]

Quincy is discussing the event tomorrow live on Twitter right now (you can actually hear notifications from this thread on his stream).

https://twitter.com/stormchaserQ/status/1130320524385505280

[SmokeEater]

Didn't say who.

Sent from my SM-G973U using Tapatalk

[jpeters3]

2 minutes ago, SmokeEater said:

Yup, saw it firsthand. Wasn't gonna put it out yet, but since you did I'll confirm, lol. Parts of W TX, TX Panhandle and W OK.

Sent from my SM-G973U using Tapatalk
 

Doesn't change the uncertainty, IMO, but probably rightfully acknowledges the possible historic "ceiling" event.  If this event goes, it will go big.

[RCNYILWX]

Since Broyles did the 01z update this evening, it'll be him. He also did the previous 06z Day 1 outlook.

Sent from my SM-G965U using Tapatalk

[bjc3395]

I like to use the HRRR as a time-lagged ensemble, and I gotta say.. The trends on the HRRR *aren't* pretty.

 

Potentially historic setup tomorrow.

[jojo762]

Just now, bjc3395 said:

I like to use the HRRR as a time-lagged ensemble, and I gotta say.. The trends on the HRRR *aren't* pretty.

 

Potentially historic setup tomorrow.

Hour 18 (21Z) on the 03Z HRRR is *unreal*...

[hlcater]

Yea it's very interesting that it's trending *down*, farther away from the WRF suite. The HRRR was significant as it was, but is seemingly getting more significant. Not good.

[jpeters3]

Just for fun, output from a 250 m horizontal grid spacing simulation I ran with one of the insane NAM soundings.  Shading is simulated radar reflectivity at 1 km, black outline is 3 m/s 1 km updraft, and blue contours are surface temperature deficit.  

REFL_175.pdf

[jpeters3]

As .png.

[AppsRunner]

Coincidentally in Norman this week for the HWT. The mood is pretty ominous.

Really don’t like the look of the flash flooding threat either

[hlcater]

I also think even barring any MCS activity along/north of warm front tomorrow morning(unlikely, but just for purposes of this post), I think new warm front development is gonna grow upscale into an MCS almost immediately. High CAPE values, coupled with a very strong 50kt LLJ and largely boundary parallel storm motion vectors scream upscale growth and subsequently, this is likely to be where the highest flash flooding threat is located. Given the strong low level shear, decent 0-3km CAPE(~150 J/kg) and low LCLs, even if a large MCS blows up, still could have a threat of embedded tornadic circulations, coupled with possible flash flooding? That has the potential to pose further issues, even if the significant tornado threat is farther away from the warm front.

[yoda]

Blue box coming for W TX around 07z

https://www.spc.noaa.gov/products/md/md0696.html

[hlcater]

Also was just thinking about the possibility of dual high risks tomorrow. One issued by the WPC for flooding in N OK. The other being issued by the SPC for tornadoes, as it sounds like we're already getting that one. Don't think that's ever happened before, but I also don't think the WPC has been doing SPC style risks for very long, so small sample size.

[jojo762]

Presented without comment. 

[bjc3395]

Probably skewed by CAMs with MCS/linear modes which produce large swaths of High UH usually. But the W TX signal is legit. 

[Quincy]

4 minutes ago, bjc3395 said:

Probably skewed by CAMs with MCS/linear modes which produce large swaths of High UH usually. But the W TX signal is legit. 

It's also the max of where the parameters overlap (larger 0-1km SRH north/larger buoyancy south). That's why SPC SREF tornado ingredients/probability has been 75-90% in that same part of southwestern Oklahoma. The bullseye isn't always where the most storms verify.

[Indystorm]

I wonder how many PDS tornado watches we will end up having this Monday.  Glad to hear via various media that people in the affected areas are taking this quite seriously.

[Stebo]

3 minutes ago, Indystorm said:

I wonder how many PDS tornado watches we will end up having this Monday.  Glad to hear via various media that people in the affected areas are taking this quite seriously.

Probably 1 or 2.

[lokee]

The talk started around Friday then it ramped up Sat night. FB has been littered with updates all day on Sunday. 

[snowlover2]

High risk it is.

Quote

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1256 AM CDT MON MAY 20 2019  
 
VALID 201200Z - 211200Z  
 
...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF WEST  
AND NORTHWEST TEXAS...THE EASTERN TEXAS PANHANDLE AND WESTERN  
OKLAHOMA...  
 
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF  
SOUTHEAST NEW YORK AND NEW ENGLAND...  
   
..SUMMARY  
 
AN OUTBREAK OF STRONG TORNADOES AND SEVERE THUNDERSTORMS IS EXPECTED  
TODAY ACROSS PARTS OF THE SOUTHERN AND CENTRAL PLAINS. IN ADDITION,  
MANY OF THE STORMS WILL HAVE VERY LARGE HAIL AND WIND DAMAGE. THE  
SEVERE THREAT WILL BE CONCENTRATED FROM WEST TEXAS AND THE TEXAS  
PANHANDLE EASTWARD ACROSS OKLAHOMA, KANSAS INTO WESTERN MISSOURI AND  
WESTERN ARKANSAS. ADDITIONAL SEVERE STORMS WITH WIND DAMAGE AND HAIL  
WILL BE POSSIBLE THIS AFTERNOON FROM SOUTHEAST NEW YORK INTO  
SOUTHERN AND CENTRAL NEW ENGLAND.  
 
...TORNADO OUTBREAK EXPECTED ACROSS THE SOUTHERN PLAINS TODAY INTO  
TONIGHT...  
   
..SOUTHERN AND CENTRAL PLAINS  
 
AN IMPRESSIVE AND POTENT UPPER-LEVEL TROUGH WILL MOVE QUICKLY  
EASTWARD ACROSS THE DESERT SOUTHWEST TODAY AS A POWERFUL 75 TO 90  
KNOT MID-LEVEL JET ROUNDS THE BASE OF THE TROUGH. AHEAD OF THE  
SYSTEM, A CORRIDOR OF STRONG INSTABILITY IS FORECAST ACROSS THE  
SOUTHERN PLAINS FROM WEST TEXAS INTO THE EASTERN TEXAS PANHANDLE AND  
EASTWARD INTO WESTERN AND CENTRAL OKLAHOMA. THIS COMBINED WITH STEEP  
MID-LEVEL LAPSE RATES AND STRONG LOW-LEVEL SHEAR WILL BE VERY  
FAVORABLE FOR SEVERE STORMS. AS THE MID-LEVEL JET EJECTS  
NORTHEASTWARD ACROSS THE SOUTHERN HIGH PLAINS THIS AFTERNOON AND  
EVENING, A TORNADO OUTBREAK IS LIKELY ACROSS THE SOUTHERN PLAINS.  
THE TORNADO OUTBREAK IS EXPECTED TO CONTINUE INTO THE OVERNIGHT  
PERIOD. THIS EVENT SHOULD RESULT IN A SIGNIFICANT THREAT TO LIFE AND  
PROPERTY.  
 
RAP FORECAST SOUNDINGS LATE THIS AFTERNOON ALONG THE INSTABILITY  
CORRIDOR FROM CHILDRESS, TEXAS NORTHEASTWARD TO CLINTON, OKLAHOMA  
SHOW MLCAPE VALUES OF 3000 TO 4500 J/KG WITH 0-6 KM SHEAR IN THE 50  
TO 65 KT RANGE. IN ADDITION, HODOGRAPHS ARE LARGE AND LOOPED WITH  
0-1 KM SHEAR VALUES IN THE 30 TO 40 KT RANGE. THIS ENVIRONMENT  
SHOULD BE VERY FAVORABLE FOR SUPERCELLS AND TORNADOES. 0-3 KM  
STORM-RELATIVE HELICITIES ARE FORECAST TO STEADILY INCREASE FROM  
ABOUT 300 M2/S2 IN THE LATE AFTERNOON TO ABOUT 450 M2/S2 BY EARLY  
EVENING AS AN ANOMALOUSLY STRONG LOW-LEVEL JET BECOMES BETTER  
FOCUSED. THIS WILL BE IDEAL FOR A TORNADO OUTBREAK WITH STRONG  
TORNADOES UPSTREAM AND TO THE WEST OF THE LOW-LEVEL JET.  
 
THE CURRENT THINKING CONCERNING THE DETAILS IS THAT THE FIRST ROUND  
OF SEVERE STORMS WILL BEGIN EARLY AS THUNDERSTORMS INITIATE IN WEST  
TEXAS AND MOVE NORTHEASTWARD INTO THE EASTERN TEXAS PANHANDLE BY MID  
TO LATE MORNING. INITIALLY, LARGE HAIL WILL BE THE MAIN THREAT BUT  
AS THESE STORMS MATURE, TORNADOES WILL BE POSSIBLE WITH THE STRONGER  
AND MORE DOMINANT CELLS. ADDITIONAL SUPERCELLS WITH TORNADO  
POTENTIAL ARE EXPECTED TO INITIATE NEAR THE WARM FRONT IN WESTERN  
AND CENTRAL OKLAHOMA. A TORNADO THREAT WILL TRANSITION TO LARGE HAIL  
AND WIND DAMAGE AS THE STORMS MOVE INTO KANSAS TO THE NORTH SIDE OF  
THE BOUNDARY. THIS FIRST ROUND OF SEVERE STORMS IS FORECAST TO MOVE  
NORTHEASTWARD, AWAY FROM THE WARM SECTOR, ALLOWING FOR THE  
DEVELOPMENT OF EXTREME INSTABILITY DURING THE MID TO LATE AFTERNOON  
FROM NORTHWEST TEXAS INTO SOUTHWEST OKLAHOMA.  
 
THE SECOND ROUND OF SEVERE STORMS IS EXPECTED TO START DURING THE  
LATE AFTERNOON AS REPEAT INITIATION TAKES PLACE IN WEST TEXAS. RAPID  
SUPERCELL FORMATION IS FORECAST ALONG THE I-27 CORRIDOR FROM THE  
VICINITY OF LUBBOCK NORTHWARD TO JUST SOUTH OF AMARILLO. A CLUSTER  
OF TORNADIC SUPERCELLS IS THEN FORECAST TO MOVE NORTHEASTWARD INTO  
NORTHWEST TEXAS AND THE SOUTHEASTERN TEXAS PANHANDLE DURING THE  
EARLY EVENING. ADDITIONAL TORNADIC SUPERCELLS ARE FORECAST TO  
RAPIDLY DEVELOP IN SOUTHWEST OKLAHOMA AND MOVE NORTHEASTWARD INTO  
WEST-CENTRAL OKLAHOMA. AT THAT TIME, THE STRENGTHENING LOW-LEVEL JET  
WILL COUPLE WITH A HIGHLY PROGRESSIVE AND SEASONABLY STRONG  
MID-LEVEL JET, MAKING CONDITIONS FAVORABLE FOR LONG-TRACK STRONG  
TORNADOES AND POSSIBLY VIOLENT TORNADOES.  
 
THE GREATEST THREAT FOR LONG-TRACK TORNADOES WILL EXIST ALONG THE  
CORRIDOR FROM NEAR LUBBOCK NORTHEASTWARD TO CHILDRESS, ALTUS,  
LAWTON, CLINTON TO JUST WEST OF THE OKLAHOMA CITY AND ENID  
VICINITIES. AFTER CONSIDERABLE DELIBERATION, A HIGH RISK WILL BE  
ISSUED FOR PARTS OF WEST TEXAS, THE SOUTHEASTERN TEXAS PANHANDLE  
INTO WESTERN OKLAHOMA.  
 
IN ADDITION TO THE TORNADO THREAT, CONDITIONS WILL BE VERY FAVORABLE  
FOR LARGE HAIL AND WIND DAMAGE. STRONG INSTABILITY, ENHANCED  
DEEP-LAYER SHEAR AND STEEP MID-LEVEL LAPSE RATES WILL MAKE  
HAILSTONES OF GREATER THAN 2 INCHES IN DIAMETER POSSIBLE WITH THE  
MORE INTENSE SUPERCELLS, MAINLY IN WEST TEXAS AND THE WESTERN HALF  
OF OKLAHOMA. A WIND-DAMAGE THREAT WILL ALSO EXIST ACROSS MUCH OF THE  
SOUTHERN PLAINS DUE TO THE EXPECTED INTENSE NATURE OF THE STORMS.  
THE WIND-DAMAGE THREAT, INCLUDING SOME GUSTS ABOVE 70 KT, SHOULD  
BECOME WIDESPREAD DURING THE LATE EVENING INTO THE OVERNIGHT PERIOD  
AS SQUALL LINE ORGANIZES AND MOVES QUICKLY EASTWARD ACROSS THE  
SOUTHERN PLAINS.  
   
..SOUTHEAST NEW YORK/NEW ENGLAND  
 
AN UPPER-LEVEL TROUGH WILL MOVE ACROSS SOUTHERN QUEBEC AND THE  
NORTHEAST TODAY. AT THE SURFACE, A COLD FRONT WILL ADVANCE EASTWARD  
ACROSS NEW YORK AND INTO WESTERN NEW ENGLAND. AHEAD OF THE FRONT,  
SURFACE DEWPOINTS IN THE MID 60S F SHOULD RESULT IN DESTABILIZATION  
OF THE AIRMASS BY AFTERNOON FROM SOUTHEAST NEW YORK INTO MUCH OF  
SOUTHERN AND CENTRAL NEW ENGLAND. SCATTERED THUNDERSTORM DEVELOPMENT  
IS EXPECTED AROUND MIDDAY ALONG THE COLD FRONT WITH THIS CONVECTION  
MOVING EASTWARD ACROSS THE MOIST SECTOR DURING THE AFTERNOON.  
FORECAST SOUNDINGS ALONG THE INSTABILITY AXIS FROM SPRINGFIELD,  
MASSACHUSETTS NORTHEASTWARD INTO VERMONT AT 21Z SHOW MLCAPE VALUES  
PEAKING IN THE 1000 TO 1500 J/KG RANGE AND HAVE STEEP LOW-LEVEL  
LAPSE RATES. THIS COMBINED WITH 0-6 KM SHEAR VALUES AROUND 35 KT  
SHOULD BE SUFFICIENT FOR MULTICELLS WITH WIND DAMAGE POTENTIAL. A  
FEW ROTATING STORMS WITH A LARGE-HAIL THREAT MAY ALSO DEVELOP.  
 
..BROYLES/WENDT.. 05/20/2019  

 

[yoda]

Quite a large hatched area for tornadoes 

[1900hurricane]

There it is.

[snowlover2]

 

Separate probs.

[Rtd208]

Wow this is going to be some day coming up for those areas in the high/moderate risk. I will be watching closely all day.

[hlcater]

This is some of the strongest wording I've personally read prior to an event(ie classics like 4/14/12 or 4/27/11 don't count because I read those after the event --- so basically since 2015). They weren't this bullish on any of the 2017 events. Heck, they even mentioned violent tornadoes. The amount of prior outlooks that mention violent tornadoes has to be no more than a handful.

[DanLarsen34]

This is the strongest wording I’ve seen them use in years. 4-14-12 and 4-27-2011 are the only recent ones I recall coming close (purely based on wording). It’s very rare, but definitely warranted given this extremely high-end set-up.

[lokee]

 

 The tornado outbreak is expected to continue into the overnight
   period. This event should result in a significant threat to life and
   property.

 

That is some language there.