Alert archive / Oklahoma / Mesoscale Discussions in 2021
Mesoscale Discussion 767
The Storm Prediction Center issued this mesoscale discussion at May 27, 2021, 1:39 PM CDT for 12 counties in Oklahoma. It was in force for 66 min.
The area
The outline as issued.
The facts
- Issued
- May 27, 2021, 1:39 PM CDT (18:39 UTC)
- Expired
- May 27, 2021, 2:45 PM CDT
- In force
- 66 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 215
Counties Blaine County, OK, Garfield County, OK, Grant County, OK, Kay County, OK, Kingfisher County, OK, Logan County, OK, Major County, OK, Noble County, OK, Osage County, OK, Pawnee County, OK, Payne County, OK, Washington County, OK
The radar
The Vance AFB radar (KVNX), 101 km from the middle of the area, began a volume at 18:40 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
Norman, OK (KOUN), launched 12:00Z, 6.7 hours before the alert went out and 129 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
- 2431 J/kg
- Mixed-layer CIN
- -121 J/kg
- Mixed-layer LCL
- 765 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km storm-relative helicity
- 264 m²/s²
- 0-3 km storm-relative helicity
- 360 m²/s²
- Significant tornado parameter
- 1.5
- Supercell composite
- 7.5
The text
As transmitted.
635
ACUS11 KWNS 271839
SWOMCD
SPC MCD 271839
OKZ000-271945-
Mesoscale Discussion 0767
NWS Storm Prediction Center Norman OK
0139 PM CDT Thu May 27 2021
Areas affected...northern Oklahoma
Concerning...Tornado Watch 215...
Valid 271839Z - 271945Z
The severe weather threat for Tornado Watch 215 continues.
SUMMARY...Threat for large to very large hail, damaging wind and a
couple of tornadoes will remain highest across the northern third of
OK next couple of hours.
DISCUSSION...Scattered thunderstorms continue to develop across the
northern third of OK. Several supercells with large hail have
already been observed. While low-level hodographs are relatively
small, effective bulk shear from 35-45 kt will continue to support
organized storms including supercells. Vance radar indicates some
storms are interacting with a southward-moving outflow boundary.
While this boundary is likely only partially modified at the present
time, further modification could locally augment the tornado threat
this afternoon.
..Dial.. 05/27/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TSA...OUN...
LAT...LON 36339597 35639745 35599878 36289906 36809791 36969607
36939560 36339597SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 26, 7:32 PM CDT | Mesoscale Discussion | SPC | Beaver, Ellis, Harper | 88 min |
| May 26, 11:26 PM CDT | Mesoscale Discussion | SPC | Alfalfa, Beckham, Blaine, Caddo, Canadian, Custer and 20 more | 64 min |
| May 27, 11:04 AM CDT | Mesoscale Discussion | SPC | Adair, Cherokee, Craig, Delaware, Mayes, Nowata and 5 more | 86 min |
| May 27, 11:29 AM CDT | Mesoscale Discussion | SPC | Adair, Alfalfa, Beckham, Blaine, Caddo, Canadian and 39 more | 61 min |
| May 27, 11:58 AM CDT | Tornado Watch | SPC | Adair, Alfalfa, Atoka, Beckham, Blaine, Bryan and 66 more | 9 hr |
| May 27, 3:25 PM CDT | Mesoscale Discussion | SPC | Blaine, Canadian, Craig, Creek, Custer, Dewey and 13 more | 95 min |
| May 27, 5:34 PM CDT | Mesoscale Discussion | SPC | Caddo, Cleveland, Comanche, Garvin, Grady, McClain and 2 more | 56 min |
| May 27, 6:24 PM CDT | Mesoscale Discussion | SPC | Harmon | 2 hr |
Nearby
Mesoscale Discussions in Oklahoma, 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.