Alert archive / Oklahoma / Mesoscale Discussions in 2021
Mesoscale Discussion 771
The Storm Prediction Center issued this mesoscale discussion at May 27, 2021, 3:25 PM CDT for 19 counties in Oklahoma. It was in force for 95 min.
The area
The outline as issued.
The facts
- Issued
- May 27, 2021, 3:25 PM CDT (20:25 UTC)
- Expired
- May 27, 2021, 5:00 PM CDT
- In force
- 95 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 215
Counties Blaine County, OK, Canadian County, OK, Craig County, OK, Creek County, OK, Custer County, OK, Dewey County, OK, Garfield County, OK, Kingfisher County, OK, Lincoln County, OK, Logan County, OK, Major County, OK, Noble County, OK, Nowata County, OK, Osage County, OK, Pawnee County, OK, Payne County, OK, Rogers County, OK, Tulsa County, OK, Washington County, OK
The radar
The Vance AFB radar (KVNX), 78 km from the middle of the area, began a volume at 20:24 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, 8.4 hours before the alert went out and 115 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.
488
ACUS11 KWNS 272025
SWOMCD
SPC MCD 272025
OKZ000-272200-
Mesoscale Discussion 0771
NWS Storm Prediction Center Norman OK
0325 PM CDT Thu May 27 2021
Areas affected...northern Oklahoma
Concerning...Tornado Watch 215...
Valid 272025Z - 272200Z
The severe weather threat for Tornado Watch 215 continues.
SUMMARY...Storms will remain capable of producing large to very
large hail, damaging wind and a couple tornadoes next couple hours
mainly across the northern half of Oklahoma.
DISCUSSION...As of mid afternoon storms continue developing across
northern OK. Most thunderstorm development has become confined to
the cool side of a couple of outflow boundaries. These storms are
probably slightly elevated, but will remain capable of producing
mainly isolated large hail and damaging wind. Farther west
additional storms are beginning to develop along the cold front
across northwest OK. These storms will be surface based and will
likely become rapidly severe and organized as supercells shortly
after initiation. VWP from Twin Lakes show the mid-level winds have
strengthened to 50 kt and size of low-level hodographs has increased
slightly. The best potential for isolated tornadoes will probably be
with storms that initially develop across western and west central
OK then move east and interact with the modifying outflow boundary
before becoming slightly elevated as they move deeper into the
cooler side of the boundary.
..Dial.. 05/27/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TSA...OUN...
LAT...LON 36689827 36659727 36919588 36919495 36579488 35649685
35519799 35649890 35639960 35939968 36689827SPC 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, 1:39 PM CDT | Mesoscale Discussion | SPC | Blaine, Garfield, Grant, Kay, Kingfisher, Logan and 6 more | 66 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.