Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 577
The Storm Prediction Center issued this mesoscale discussion at May 9, 2021, 8:06 PM CDT for 38 counties in Texas. It was in force for 114 min.
The area
The outline as issued.
The facts
- Issued
- May 9, 2021, 8:06 PM CDT (01:06 UTC)
- Expired
- May 9, 2021, 10:00 PM CDT
- In force
- 114 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 159
All 38 counties
Anderson County, TX, Bell County, TX, Blanco County, TX, Bosque County, TX, Burnet County, TX, Comal County, TX, Coryell County, TX, Ellis County, TX, Falls County, TX, Freestone County, TX, Gillespie County, TX, Hamilton County, TX, Hays County, TX, Henderson County, TX, Hill County, TX, Hopkins County, TX, Houston County, TX, Kaufman County, TX, Kendall County, TX, Kerr County, TX, Lampasas County, TX, Leon County, TX, Limestone County, TX, Llano County, TX, Madison County, TX, Mason County, TX, McLennan County, TX, Milam County, TX, Mills County, TX, Navarro County, TX, Polk County, TX, Rains County, TX, Robertson County, TX, San Saba County, TX, Travis County, TX, Trinity County, TX, Van Zandt County, TX, Williamson County, TX
The radar
The Ft Hood radar (KGRK), 64 km from the middle of the area, began a volume at 01:09 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Fort Worth, TX (KFWD), launched 00:00Z, 1.1 hours before the alert went out and 187 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1412 m above ground
- 0-6 km bulk shear
- 49 kt
- 0-1 km storm-relative helicity
- -14 m²/s²
- 0-3 km storm-relative helicity
- 90 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
The text
As transmitted.
910
ACUS11 KWNS 100107
SWOMCD
SPC MCD 100106
TXZ000-100300-
Mesoscale Discussion 0577
NWS Storm Prediction Center Norman OK
0806 PM CDT Sun May 09 2021
Areas affected...Central Texas
Concerning...Severe Thunderstorm Watch 159...
Valid 100106Z - 100300Z
The severe weather threat for Severe Thunderstorm Watch 159
continues.
SUMMARY...A large hail and wind damage threat will continue over the
next few hours across central Texas. Although the severe threat is
not expected to move to the southeast of WW 159, the situation will
continue to be monitored.
DISCUSSION...The latest radar imagery shows two supercell
thunderstorms ongoing in central Texas. These thunderstorms have
developed along the northwestern edge of a pocket of strong
instability with the RAP estimating MLCAPE in the 3500 to 4500 J/kg
range. The storms are located just ahead of a cold front in an area
of maximized low-level convergence. This is supporting convective
development in spite of the lack of large-scale ascent. The storms
are located along the eastern edge of the steeper mid-level lapse
rates. The RAP is estimating 700-500 mb lapse rate across the Texas
Hill Country at 7.5 to 8.0 C/km with 0-6 km shear near 50 kt. This
will continue the threat for supercells with large hail. Hailstones
of greater than 2 inches in diameter will be possible. The southern
storm has turned southeastward and may affect areas to the northeast
of the San Antonio Metro along the I-35 corridor later this evening.
..Broyles.. 05/10/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LCH...SHV...HGX...FWD...EWX...SJT...
LAT...LON 29629824 29659832 29719838 29759858 29759878 29829895
29899918 29939967 30099969 30109973 30269974 30289929
30489929 30499946 30999947 30999912 31449909 31689869
31769826 31929817 32199759 32249711 32559709 32569654
32809650 32849593 32999596 33019584 33259574 33359535
33109538 32939532 32919564 32559559 32329548 31969548
31799541 31649522 31379492 31129484 31039472 30639458
30509454 30469482 30599500 30829514 30849525 30919539
31019542 30869572 30779605 30889615 30959624 30749643
30739659 30539699 30409743 30149758 29739801 29629824SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 10, 10:28 AM CDT | Mesoscale Discussion | SPC | Delta, Fannin, Grayson, Lamar, Red River | 92 min |
| May 10, 1:04 PM CDT | Mesoscale Discussion | SPC | Edwards, Kinney, Real, Terrell, Val Verde | 116 min |
| May 10, 1:48 PM CDT | Severe Thunderstorm Watch | SPC | Atascosa, Bandera, Bexar, Crockett, Dimmit, Edwards and 14 more | 10 hr |
| May 10, 2:07 PM CDT | Mesoscale Discussion | SPC | Grimes, Houston, Madison, Polk, San Jacinto, Trinity and 2 more | 113 min |
| May 10, 5:47 PM CDT | Mesoscale Discussion | SPC | Brazos, Grimes, Jasper, Montgomery, Polk, San Jacinto and 2 more | 88 min |
| May 10, 6:05 PM CDT | Mesoscale Discussion | SPC | Bee, Dimmit, Duval, Jim Wells, La Salle, Live Oak and 2 more | 2 hr |
Nearby
Mesoscale Discussions in Texas, 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; radar from the NEXRAD Level II archive.