Alert archive / Oklahoma / Mesoscale Discussions in 2018
Mesoscale Discussion 76
The Storm Prediction Center issued this mesoscale discussion at Feb 20, 2018, 9:40 AM CST for 5 counties in Kansas; 12 counties in Oklahoma. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 20, 2018, 9:40 AM CST (15:40 UTC)
- Expired
- Feb 20, 2018, 1:15 PM CST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
Counties Chautauqua County, KS, Labette County, KS, Montgomery County, KS, Neosho County, KS, Wilson County, KS, Cleveland County, OK, Creek County, OK, Grady County, OK, Lincoln County, OK, Logan County, OK, McClain County, OK, Nowata County, OK, Oklahoma County, OK, Osage County, OK, Pawnee County, OK, Payne County, OK, Washington County, OK
The radar
The Norman radar (KTLX), 80 km from the middle of the area, began a volume at 15:39 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, 3.7 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
- 1095 J/kg
- Mixed-layer CIN
- -55 J/kg
- Mixed-layer LCL
- 725 m above ground
- 0-6 km bulk shear
- 61 kt
- 0-1 km storm-relative helicity
- 425 m²/s²
- 0-3 km storm-relative helicity
- 450 m²/s²
- Significant tornado parameter
- 3.0
- Supercell composite
- 15.4
The text
As transmitted.
151
ACUS11 KWNS 201540
SWOMCD
SPC MCD 201540
KSZ000-OKZ000-201915-
Mesoscale Discussion 0076
NWS Storm Prediction Center Norman OK
0940 AM CST Tue Feb 20 2018
Areas affected...central into northeast OK...southeast KS
Concerning...Freezing rain
Valid 201540Z - 201915Z
SUMMARY...Freezing rain rates ranging from 0.02-0.20 inch per hour
expected over the next several hours. Areas in northeast OK and
southeast KS currently above freezing and reporting rain as of
930am, will likely transition to freezing rain later this morning.
DISCUSSION...Radar mosaic and NLDN lightning data indicate a shield
of convective precipitation from southwest OK northeast through
southeast KS as of mid morning. A surface front is accelerating
southeast across the I-44 corridor in OK and southwest MO. The 32
degree F demarcation is located in a wavy fashion from roughly
Chickasha, OK north-northeast to near Bartlesville, OK and northeast
to Bourbon County, KS. The quickest translation of the front will
occur over central OK during the next few hours where northerly
surface winds behind the front are gusting to around 30 mph.
Rainfall observations from the OK Mesonet have indicated rainfall
amounts in areas below 32 deg F have ranged from a few hundredths to
around 0.40 inch during the 830-930am period. Expecting convective
enhancement to the rainfall rates to continue during the morning
from central OK northeast into southeast KS. As a result, freezing
rain rates will range from 0.02 inch-0.05 inch/hour but locally in
the 0.10-0.20 inch range in the heavier bursts.
..Smith.. 02/20/2018
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...SGF...TSA...ICT...OUN...
LAT...LON 34979842 37829563 37749501 37219488 35389677 34849761
34779810 34979842SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 20, 4:21 AM CST | Mesoscale Discussion | SPC | Barber, Chase, Harper, Harvey, Kingman, Lyon and 8 more | 3 hr |
| Feb 20, 8:52 AM CST | Mesoscale Discussion | SPC | Carter, Johnston, Love, Marshall | 113 min |
| Feb 20, 11:11 AM CST | Mesoscale Discussion | SPC | Carter, Jefferson, Love | 94 min |
Nearby
Mesoscale Discussions in Oklahoma, 2018Mesoscale Discussions in Kansas, 2018Every mesoscale discussion in 2018
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.