Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 655
The Storm Prediction Center issued this mesoscale discussion at May 17, 2021, 4:36 PM MDT for Curry County, New Mexico; 44 counties in Texas. It was in force for 84 min.
The area
The outline as issued.
The facts
- Issued
- May 17, 2021, 4:36 PM MDT (22:36 UTC)
- Expired
- May 17, 2021, 6:00 PM MDT
- In force
- 84 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 182
All 45 counties
Curry County, NM, Andrews County, TX, Armstrong County, TX, Bailey County, TX, Borden County, TX, Briscoe County, TX, Castro County, TX, Cochran County, TX, Crane County, TX, Crockett County, TX, Crosby County, TX, Dawson County, TX, Deaf Smith County, TX, Dickens County, TX, Ector County, TX, Edwards County, TX, Floyd County, TX, Gaines County, TX, Garza County, TX, Glasscock County, TX, Hale County, TX, Hockley County, TX, Howard County, TX, Irion County, TX, Kent County, TX, Lamb County, TX, Lubbock County, TX, Lynn County, TX, Martin County, TX, Midland County, TX, Mitchell County, TX, Motley County, TX, Parmer County, TX, Randall County, TX, Reagan County, TX, Schleicher County, TX, Scurry County, TX, Sterling County, TX, Sutton County, TX, Swisher County, TX, Terrell County, TX, Terry County, TX, Upton County, TX, Val Verde County, TX, Yoakum County, TX
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Midland Regional, TX (KMAF), launched 12:00Z, 10.6 hours before the alert went out and 83 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 1892 J/kg
- Mixed-layer CIN
- -22 J/kg
- Mixed-layer LCL
- 750 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 54 m²/s²
- 0-3 km storm-relative helicity
- 204 m²/s²
- Significant tornado parameter
- 1.3
- Supercell composite
- 6.7
The text
As transmitted.
693
ACUS11 KWNS 172237
SWOMCD
SPC MCD 172236
TXZ000-NMZ000-180000-
Mesoscale Discussion 0655
NWS Storm Prediction Center Norman OK
0536 PM CDT Mon May 17 2021
Areas affected...TX Panhandle into Southwest TX...Far eastern NM
Concerning...Tornado Watch 182...
Valid 172236Z - 180000Z
The severe weather threat for Tornado Watch 182 continues.
SUMMARY...Supercells with very large hail will be the primary threat
in the short term, but the tornado and damaging wind threat will
likely increase some into the early evening.
DISCUSSION...Scattered supercells are ongoing at 2230Z from far
east-central NM into southwest TX. With little to no MLCINH
remaining and moderate-to-strong instability in place (MLCAPE of
2000-3000 J/kg), continued storm development and intensification is
expected through 00Z. Very large hail (potentially larger than
baseballs) will the primary short-term threat, given effective shear
of 40-50 kt and very steep midlevel lapse rates (as noted on 18Z AMA
and MAF and 20Z DRT soundings).
Low-level flow/shear is expected to increase somewhat into this
evening. As this occurs, the tornado threat may increase with any
remaining discrete supercells. The increasing low-level jet may also
eventually support some upscale growth with time, which would lead
to an increase in the severe wind threat. Isolated significant wind
gusts (65+ kt) cannot be ruled out, especially across the central
and southern portion of WW 182 where greater boundary-layer
heating/mixing has occurred this afternoon.
..Dean.. 05/17/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...EWX...SJT...LUB...AMA...MAF...ABQ...
LAT...LON 29990251 34590351 35360162 34910073 33930069 32120074
29969995 29800002 29470074 29580143 29940236 29990251SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 17, 12:39 PM MDT | Mesoscale Discussion | SPC | Colfax, Harding, Mora, San Miguel, Santa Fe, Taos and 1 more | 2 hr |
| May 17, 1:11 PM MDT | Mesoscale Discussion | SPC | Curry, De Baca, Lea, Roosevelt | 2 hr |
| May 17, 1:39 PM MDT | Severe Thunderstorm Watch | SPC | Colfax, Guadalupe, Harding, Mora, San Miguel, Santa Fe and 2 more | 8 hr |
| May 17, 2:04 PM MDT | Tornado Watch | SPC | Curry, Quay, Roosevelt | 8 hr |
| May 17, 4:10 PM MDT | Mesoscale Discussion | SPC | Colfax, Guadalupe, Harding, Mora, Quay, San Miguel and 1 more | 2 hr |
| May 16, 6:08 PM MDT | Severe Thunderstorm Watch | SPC | Cottle, Crosby, Dickens, Floyd, Garza, Hale and 8 more | 6 hr |
| May 16, 7:54 PM MDT | Mesoscale Discussion | SPC | Briscoe, Cottle, Foard, Hall, King, Knox and 1 more | 96 min |
| May 16, 8:38 PM MDT | Severe Thunderstorm Watch | SPC | Archer, Baylor, Clay, Foard, Hardeman, Haskell and 10 more | 4 hr |
| May 16, 9:46 PM MDT | Mesoscale Discussion | SPC | Baylor, Cottle, Dickens, Foard, Haskell, King and 3 more | 59 min |
| May 17, 12:09 AM MDT | Mesoscale Discussion | SPC | Archer, Baylor, Clay, Crosby, Dickens, Fisher and 17 more | 96 min |
| May 17, 8:18 AM MDT | Mesoscale Discussion | SPC | Jasper, Jefferson, Newton, Orange | 117 min |
| May 17, 11:47 AM MDT | Mesoscale Discussion | SPC | Austin, Bastrop, Bell, Blanco, Brazoria, Brazos and 29 more | 88 min |
| May 17, 3:44 PM MDT | Tornado Watch | SPC | Baylor, Childress, Cottle, Fisher, Foard, Hardeman and 10 more | 6 hr |
| May 17, 3:53 PM MDT | Mesoscale Discussion | SPC | Baylor, Callahan, Childress, Cottle, Fisher, Foard and 11 more | 97 min |
| May 17, 5:13 PM MDT | Mesoscale Discussion | SPC | Dimmit, La Salle, Webb | 92 min |
| May 17, 5:40 PM MDT | Severe Thunderstorm Watch | SPC | Dimmit, Frio, La Salle, Maverick, Webb, Zavala | 4 hr |
Nearby
Mesoscale Discussions in Texas, 2021Mesoscale Discussions in New Mexico, 2021Every mesoscale discussion in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.