Alert archive / Texas / Mesoscale Discussions in 2017
Mesoscale Discussion 484
The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2017, 5:23 AM CDT for 54 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 11, 2017, 5:23 AM CDT (10:23 UTC)
- Expired
- Apr 11, 2017, 7:30 AM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
All 54 counties
Anderson County, TX, Angelina County, TX, Bastrop County, TX, Bell County, TX, Bexar County, TX, Blanco County, TX, Bosque County, TX, Brazos County, TX, Burleson County, TX, Burnet County, TX, Caldwell County, TX, Cherokee County, TX, Comal County, TX, Coryell County, TX, Ellis County, TX, Falls County, TX, Fayette County, TX, Freestone County, TX, Gregg County, TX, Grimes County, TX, Guadalupe County, TX, Hamilton County, TX, Hays County, TX, Henderson County, TX, Hill County, TX, Houston County, TX, Kaufman County, TX, Kendall County, TX, Lampasas County, TX, Lee County, TX, Leon County, TX, Limestone County, TX, Madison County, TX, McLennan County, TX, Milam County, TX, Montgomery County, TX, Nacogdoches County, TX, Navarro County, TX, Panola County, TX, Polk County, TX, Robertson County, TX, Rusk County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Smith County, TX, Travis County, TX, Trinity County, TX, Upshur County, TX, Van Zandt County, TX, Walker County, TX, Washington County, TX, Williamson County, TX, Wood County, TX
The radar
The Ft Hood radar (KGRK), 46 km from the middle of the area, began a volume at 10:21 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, 10.4 hours before the alert went out and 238 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
- 143 J/kg
- Mixed-layer CIN
- -246 J/kg
- Mixed-layer LCL
- 1066 m above ground
- 0-6 km bulk shear
- 49 kt
- 0-1 km storm-relative helicity
- 60 m²/s²
- 0-3 km storm-relative helicity
- 190 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 5.4
The text
As transmitted.
791
ACUS11 KWNS 111024
SWOMCD
SPC MCD 111023
LAZ000-TXZ000-111230-
Mesoscale Discussion 0484
NWS Storm Prediction Center Norman OK
0523 AM CDT Tue Apr 11 2017
Areas affected...portions of central and eastern Texas
Concerning...Severe Thunderstorm Watch 140...
Valid 111023Z - 111230Z
The severe weather threat for Severe Thunderstorm Watch 140
continues.
SUMMARY...Increasingly isolated severe risk remains across WW 140 --
primarily in the form of large hail.
DISCUSSION...Scattered to isolated thunderstorms continue either
side of an east-northeast to west-southwest frontal zone draped
across central Texas. Storms have diminished in coverage within the
WW area itself, with a cell now over Bell county currently the only
storm that appears capable of producing severe weather at this time.
Meanwhile, more widespread storms are ongoing both north and
northeast of the watch. The storms north of the watch -- which
earlier posed a risk for marginal hail -- seem to have diminished in
intensity to generally below severe levels at this time. Meanwhile,
a semi-organized/bowing cluster of storms is moving out of eastern
portions of the WW -- into an increasingly stable environment.
Given overall trends -- both environmentally and in radar evolution,
prospects for any appreciable increase in severe risk seem minimal
over the next few hours. As such, the currently scheduled 12z
expiration time for WW 140 appears reasonable.
..Goss.. 04/11/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LCH...SHV...HGX...FWD...EWX...SJT...
LAT...LON 29339809 29589900 30339845 31019848 31999827 33019511
32269399 31069422 30409508 29609713 29339809SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 10, 9:35 PM CDT | Mesoscale Discussion | SPC | Anderson, Bandera, Bastrop, Bell, Blanco, Brazos and 44 more | 85 min |
| Apr 10, 11:03 PM CDT | Severe Thunderstorm Watch | SPC | Anderson, Bandera, Bastrop, Bell, Bexar, Blanco and 33 more | 8 hr |
| Apr 11, 2:05 AM CDT | Mesoscale Discussion | SPC | Anderson, Bandera, Bastrop, Bell, Bexar, Blanco and 54 more | 115 min |
| Apr 11, 1:43 PM CDT | Mesoscale Discussion | SPC | Aransas, Atascosa, Bee, Bexar, Brazoria, Caldwell and 18 more | 2 hr |
Nearby
Mesoscale Discussions in Texas, 2017Every mesoscale discussion in 2017
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.