Alert archive / Oklahoma / Mesoscale Discussions in 2021
Mesoscale Discussion 1908
The Storm Prediction Center issued this mesoscale discussion at Oct 27, 2021, 1:13 AM CDT for 21 counties in Oklahoma. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Oct 27, 2021, 1:13 AM CDT (06:13 UTC)
- Expired
- Oct 27, 2021, 3:15 AM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 538
All 21 counties
Atoka County, OK, Bryan County, OK, Coal County, OK, Creek County, OK, Hughes County, OK, Johnston County, OK, Lincoln County, OK, McIntosh County, OK, Muskogee County, OK, Noble County, OK, Okfuskee County, OK, Okmulgee County, OK, Osage County, OK, Pawnee County, OK, Payne County, OK, Pittsburg County, OK, Pontotoc County, OK, Seminole County, OK, Tulsa County, OK, Wagoner County, OK, Washington County, OK
The radar
The Norman radar (KTLX), 81 km from the middle of the area, began a volume at 06:17 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 00:00Z, 6.2 hours before the alert went out and 96 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
- 791 J/kg
- Mixed-layer CIN
- -225 J/kg
- Mixed-layer LCL
- 916 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 277 m²/s²
- 0-3 km storm-relative helicity
- 380 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.5
The text
As transmitted.
961
ACUS11 KWNS 270614
SWOMCD
SPC MCD 270613
OKZ000-270815-
Mesoscale Discussion 1908
NWS Storm Prediction Center Norman OK
0113 AM CDT Wed Oct 27 2021
Areas affected...Parts of central into eastern Oklahoma
Concerning...Severe Thunderstorm Watch 538...
Valid 270613Z - 270815Z
The severe weather threat for Severe Thunderstorm Watch 538
continues.
SUMMARY...Localized severe wind gusts with the potential for an
isolated tornado may continue another or or so, before tending to
diminish as the squall line advances east of the watch by 08-09Z.
DISCUSSION...A northeastward surging segment of the squall line has
crossed the Interstate 35 corridor of central Oklahoma with mostly
sub-severe wind gusts recorded in ASOS and mesonet observations, but
with a number of embedded cyclonic circulations evident along the
leading edge of the surface cold pool. Low-level vertical shear is
strong eastward through much of the remainder of Oklahoma, beneath a
50 kt southerly 850 mb jet. However, the squall line is in the
process of progressing across and east of a surface warm front, with
a substantive near surface stable layer persisting to the northeast
of the front. With continued eastward progression, even potential
for localized severe wind gusts and/or an isolated tornado, seems
likely to diminish within the next few hours.
..Kerr.. 10/27/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TSA...OUN...
LAT...LON 36809696 36859598 36259553 35579531 34379553 33859619
34139685 34829694 35399685 36219718 36649734 36809696SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 26, 7:23 PM CDT | Severe Thunderstorm Watch | SPC | Caddo, Comanche, Cotton, Grady, Greer, Harmon and 5 more | 8 hr |
| Oct 26, 8:59 PM CDT | Mesoscale Discussion | SPC | Alfalfa, Blaine, Custer, Dewey, Ellis, Harper and 4 more | 91 min |
| Oct 26, 9:37 PM CDT | Mesoscale Discussion | SPC | Beckham, Caddo, Comanche, Cotton, Grady, Greer and 5 more | 83 min |
| Oct 26, 10:09 PM CDT | Mesoscale Discussion | SPC | Atoka, Bryan, Carter, Cleveland, Coal, Creek and 31 more | 66 min |
| Oct 26, 10:26 PM CDT | Severe Thunderstorm Watch | SPC | Atoka, Bryan, Canadian, Carter, Cleveland, Coal and 26 more | 7 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.