Alert archive / Texas / Mesoscale Discussions in 2017
Mesoscale Discussion 558
The Storm Prediction Center issued this mesoscale discussion at Apr 26, 2017, 5:37 AM CDT for 20 counties in Arkansas; 7 counties in Oklahoma; 21 counties in Texas. It was in force for 113 min.
The area
The outline as issued.
The facts
- Issued
- Apr 26, 2017, 5:37 AM CDT (10:37 UTC)
- Expired
- Apr 26, 2017, 7:30 AM CDT
- In force
- 113 min
- Issued by
- the Storm Prediction Center
All 48 counties
Conway County, AR, Crawford County, AR, Franklin County, AR, Garland County, AR, Howard County, AR, Johnson County, AR, Little River County, AR, Logan County, AR, Madison County, AR, Montgomery County, AR, Newton County, AR, Perry County, AR, Pike County, AR, Polk County, AR, Pope County, AR, Scott County, AR, Sebastian County, AR, Sevier County, AR, Van Buren County, AR, Yell County, AR, Atoka County, OK, Bryan County, OK, Choctaw County, OK, Latimer County, OK, LeFlore County, OK, McCurtain County, OK, Pushmataha County, OK, Bowie County, TX, Camp County, TX, Collin County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Fannin County, TX, Franklin County, TX, Grayson County, TX, Hopkins County, TX, Hunt County, TX, Kaufman County, TX, Lamar County, TX, Morris County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Tarrant County, TX, Titus County, TX, Van Zandt County, TX, Wood County, TX
The radar
The Western Arkansas radar (KSRX), 108 km from the middle of the area, began a volume at 10:36 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Shreveport, LA (KBAD), launched 00:00Z, 10.6 hours before the alert went out and 223 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
- 146 J/kg
- Mixed-layer CIN
- -496 J/kg
- Mixed-layer LCL
- 1221 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 78 m²/s²
- 0-3 km storm-relative helicity
- 158 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
533
ACUS11 KWNS 261038
SWOMCD
SPC MCD 261037
ARZ000-TXZ000-OKZ000-261230-
Mesoscale Discussion 0558
NWS Storm Prediction Center Norman OK
0537 AM CDT Wed Apr 26 2017
Areas affected...Arkansas...Southeast Oklahoma...Northeast Texas
Concerning...Severe Thunderstorm Watch 160...
Valid 261037Z - 261230Z
The severe weather threat for Severe Thunderstorm Watch 160
continues.
SUMMARY...The severe threat is expected to continue across parts of
eastern Oklahoma and northwestern Arkansas this morning. Severe
storms may also develop across parts of northeast Texas. WW issuance
will likely be needed across parts of this region over the next
hour.
DISCUSSION...The latest radar analysis shows a developing line of
storms extending from far northwest Arkansas southwestward to near
the Red River in southern Oklahoma. This line of storms is being
supported by forcing along a cold front and lift associated with the
western edge of belt of strong low-level flow. Ahead of the line of
storms, moisture advection and surface heating this morning will
maintain moderate instability across much of the Arklatex. This
combined with large-scale ascent associated with an upper-level
trough moving into the southern Plains will help the line to
gradually become more organized.
Regional WSR-88D VWPs show 0-6 km shear in the 60 to 75 kt range
with substantial directional shear in the lowest 2 km AGL. This
combined with strong forcing should support squall-line development
over the next few hours. Rotating cells associated with isolated
large hail will be possible within the stronger portions of the
line. Wind damage will also be possible with bowing segments that
develop along the leading edge of the line.
..Broyles/Edwards.. 04/26/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LZK...SHV...TSA...FWD...OUN...
LAT...LON 36089369 34139667 32549771 32359581 33139451 34739288
35759207 36089369SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 25, 10:51 PM CDT | Mesoscale Discussion | SPC | Benton, Boone, Carroll, Madison, Washington | 54 min |
| Apr 25, 11:27 PM CDT | Severe Thunderstorm Watch | SPC | Benton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more | 7 hr |
| Apr 26, 1:42 AM CDT | Mesoscale Discussion | SPC | Baxter, Boone, Carroll, Crawford, Franklin, Johnson and 10 more | 2 hr |
| Apr 26, 6:00 AM CDT | Severe Thunderstorm Watch | SPC | Baxter, Boone, Carroll, Conway, Crawford, Franklin and 23 more | 7 hr |
| Apr 26, 7:29 AM CDT | Mesoscale Discussion | SPC | Baxter, Boone, Carroll, Conway, Crawford, Franklin and 23 more | 2 hr |
| Apr 26, 9:39 AM CDT | Mesoscale Discussion | SPC | Arkansas, Baxter, Bradley, Calhoun, Clark, Clay and 47 more | 36 min |
| Apr 26, 10:08 AM CDT | Tornado Watch | SPC | Arkansas, Baxter, Bradley, Calhoun, Clark, Clay and 51 more | 7 hr |
| Apr 26, 1:05 PM CDT | Mesoscale Discussion | SPC | Clark, Columbia, Dallas, Grant, Hempstead, Hot Spring and 9 more | 85 min |
| Apr 26, 3:53 PM CDT | Mesoscale Discussion | SPC | Clay | 97 min |
| Apr 26, 4:23 PM CDT | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 19 more | 67 min |
| Apr 26, 4:44 PM CDT | Tornado Watch | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 11 more | 5 hr |
| Apr 26, 5:02 PM CDT | Severe Thunderstorm Watch | SPC | Clay, Craighead, Crittenden, Cross, Greene, Lee and 4 more | 6 hr |
| Apr 26, 6:10 PM CDT | Mesoscale Discussion | SPC | Mississippi | 95 min |
| Apr 25, 7:14 PM CDT | Mesoscale Discussion | SPC | Cleveland, Craig, Creek, Delaware, Garvin, Grady and 23 more | 91 min |
| Apr 25, 10:30 PM CDT | Mesoscale Discussion | SPC | Cherokee, Cleveland, Craig, Creek, Delaware, Garvin and 17 more | 90 min |
Nearby
Mesoscale Discussions in Texas, 2017Mesoscale Discussions in Arkansas, 2017Mesoscale Discussions in Oklahoma, 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.