Alert archive / Texas / Mesoscale Discussions in 2020
Mesoscale Discussion 1663
The Storm Prediction Center issued this mesoscale discussion at Sep 1, 2020, 2:35 PM CDT for Ellis County, Harmon County, Roger Mills County, Oklahoma; 28 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 1, 2020, 2:35 PM CDT (19:35 UTC)
- Expired
- Sep 1, 2020, 5:00 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 60%
All 31 counties
Ellis County, OK, Harmon County, OK, Roger Mills County, OK, Armstrong County, TX, Briscoe County, TX, Carson County, TX, Childress County, TX, Collingsworth County, TX, Cottle County, TX, Crosby County, TX, Dickens County, TX, Donley County, TX, Fisher County, TX, Floyd County, TX, Foard County, TX, Gray County, TX, Hall County, TX, Hardeman County, TX, Haskell County, TX, Hemphill County, TX, Hutchinson County, TX, Kent County, TX, King County, TX, Knox County, TX, Lipscomb County, TX, Motley County, TX, Randall County, TX, Roberts County, TX, Stonewall County, TX, Swisher County, TX, Wheeler County, TX
The radar
The Altus AFB radar (KFDR), 128 km from the middle of the area, began a volume at 19:35 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
Amarillo Airport, TX (KAMA), launched 12:00Z, 7.6 hours before the alert went out and 150 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
- 100 J/kg
- Mixed-layer CIN
- -136 J/kg
- Mixed-layer LCL
- 1063 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 8 m²/s²
- 0-3 km storm-relative helicity
- 17 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
As transmitted.
246
ACUS11 KWNS 011935
SWOMCD
SPC MCD 011935
TXZ000-OKZ000-012200-
Mesoscale Discussion 1663
NWS Storm Prediction Center Norman OK
0235 PM CDT Tue Sep 01 2020
Areas affected...Texas Panhandle and far western Oklahoma
Concerning...Severe potential...Watch possible
Valid 011935Z - 012200Z
Probability of Watch Issuance...60 percent
SUMMARY...A few severe thunderstorms are expected to develop this
afternoon over parts of the Texas Panhandle and far western
Oklahoma. A severe thunderstorm watch may be needed in the next few
hours.
DISCUSSION...Moderate instability has redeveloped this afternoon
across the eastern TX panhandle and far western OK, where MLCAPE
values of 2000-2500 J/kg and dewpoints in the upper 60s to lower 70s
are present. An upper trough over NM will continue drifting
eastward, with midlevel height falls and cooling overspreading the
greater instability during the next few hours. This should help to
promote scattered thunderstorm development.
Forecast soundings and regional VAD profiles show relatively weak
low-level winds. However, 30-50 knot flow in the mid/upper levels
coupled with moderately steep midlevel lapse rates will promote a
few rotating storms capable of large hail and damaging winds. A
watch will be considered for this region in the next 1-3 hours as
convective initiation approaches.
..Hart/Grams.. 09/01/2020
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OUN...SJT...LUB...AMA...MAF...
LAT...LON 33160111 35020198 35850175 36540019 36269964 35249978
34279956 33549927 32979937 32680036 33160111SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 31, 8:37 PM CDT | Mesoscale Discussion | SPC | Caddo, Canadian, Cleveland, Comanche, Cotton, Craig and 17 more | 83 min |
| Aug 31, 11:39 PM CDT | Mesoscale Discussion | SPC | Atoka, Bryan, Carter, Cleveland, Coal, Garvin and 12 more | 96 min |
| Sep 1, 3:46 PM CDT | Severe Thunderstorm Watch | SPC | Beaver, Beckham, Ellis, Greer, Harmon, Harper and 2 more | 8 hr |
| Sep 1, 6:29 PM CDT | Mesoscale Discussion | SPC | Beaver, Beckham, Dewey, Ellis, Harper, Roger Mills and 1 more | 91 min |
Nearby
Mesoscale Discussions in Texas, 2020Mesoscale Discussions in Oklahoma, 2020Every mesoscale discussion in 2020
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.