Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 618
The Storm Prediction Center issued this mesoscale discussion at May 15, 2021, 12:48 PM CDT for Cameron County, Hidalgo County, Willacy County, Texas. It was in force for 87 min.
The area
The outline as issued.
The facts
- Issued
- May 15, 2021, 12:48 PM CDT (17:48 UTC)
- Expired
- May 15, 2021, 2:15 PM CDT
- In force
- 87 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Cameron County, TX, Hidalgo County, TX, Willacy County, TX
The radar
The Brownsville radar (KBRO), 65 km from the middle of the area, began a volume at 17:48 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
Brownsville Intl, TX (KBRO), launched 12:00Z, 5.8 hours before the alert went out and 68 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
- 1407 J/kg
- Mixed-layer CIN
- -11 J/kg
- Mixed-layer LCL
- 634 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 57 m²/s²
- 0-3 km storm-relative helicity
- 118 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 3.0
The text
As transmitted.
387
ACUS11 KWNS 151749
SWOMCD
SPC MCD 151748
TXZ000-151915-
Mesoscale Discussion 0618
NWS Storm Prediction Center Norman OK
1248 PM CDT Sat May 15 2021
Areas affected...Deep South TX
Concerning...Severe potential...Watch unlikely
Valid 151748Z - 151915Z
Probability of Watch Issuance...20 percent
SUMMARY...Damaging wind gusts and isolated hail are possible within
the vicinity of the Rio Grande River across Hidalgo and Cameron
Counties over the next hour or so.
DISCUSSION...Recent KBRO radar imagery has shown increased forward
progression of the convective line moving across the Lower Rio
Grande Valley. In addition, brief low-level rotation was observed
within a cell ahead of the line. Environment downstream of this line
is characterized by moderate east-southeasterly surface winds and
dewpoints in the low 70s. This type of environment should provide
ample inflow for maintenance of the ongoing line as it progresses
eastward. Given the recent radar signatures and overall convective
evolution, damaging wind gusts appear probable in the vicinity of
the Rio Grande River across Hidalgo and Cameron Counties. Isolated
hail may also occur.
..Mosier/Guyer.. 05/15/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BRO...
LAT...LON 26419852 26619819 26529743 26019727 25679745 25859851
26419852SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 14, 8:45 PM CDT | Mesoscale Discussion | SPC | Armstrong, Bailey, Briscoe, Carson, Castro, Childress and 16 more | 90 min |
| May 15, 2:25 PM CDT | Mesoscale Discussion | SPC | Culberson, Loving, Reeves, Ward, Winkler | 3 hr |
| May 15, 2:57 PM CDT | Mesoscale Discussion | SPC | Dallam, Hartley | 2 hr |
| May 15, 3:49 PM CDT | Severe Thunderstorm Watch | SPC | Armstrong, Bailey, Briscoe, Carson, Castro, Cochran and 22 more | 7 hr |
| May 15, 4:06 PM CDT | Severe Thunderstorm Watch | SPC | Andrews, Borden, Brewster, Crane, Crockett, Dawson and 15 more | 7 hr |
| May 15, 5:56 PM CDT | Mesoscale Discussion | SPC | Bailey, Castro, Cochran, Dallam, Deaf Smith, Hale and 9 more | 94 min |
| May 15, 6:35 PM CDT | Mesoscale Discussion | SPC | Andrews, Borden, Brewster, Crane, Crockett, Culberson and 18 more | 85 min |
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.