Mesoscale Discussion 1979

Issued

Dec 10, 2021, 2:44 PM CST (20:44 UTC)

Expired

Dec 10, 2021, 4:45 PM CST

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch possible

Chance of a watch

40%

Counties Audrain County, MO, Boone County, MO, Carroll County, MO, Chariton County, MO, Clark County, MO, Cooper County, MO, Howard County, MO, Knox County, MO, Lafayette County, MO, Lewis County, MO, Linn County, MO, Macon County, MO, Marion County, MO, Monroe County, MO, Pettis County, MO, Ralls County, MO, Randolph County, MO, Saline County, MO, Shelby County, MO

The Pleasant Hill radar (KEAX), 166 km from the middle of the area, began a volume at 20:45 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.

• Tornado Watch 553Dec 10, 5:20 PM CST

644 
ACUS11 KWNS 102045
SWOMCD
SPC MCD 102044 
ILZ000-MOZ000-IAZ000-102245-

Mesoscale Discussion 1979
NWS Storm Prediction Center Norman OK
0244 PM CST Fri Dec 10 2021

Areas affected...Parts of west central through northeastern Missouri
and adjacent portions of southeastern Iowa and west central Illinois

Concerning...Severe potential...Watch possible 

Valid 102044Z - 102245Z

Probability of Watch Issuance...40 percent

SUMMARY...Isolated supercell development potentially becoming
capable of producing tornadoes appears possible across parts of
north central Missouri prior to 6 PM CST.  While it is not certain
that a watch will be needed, trends are being monitored for this
possibility.

DISCUSSION...The center of a deepening surface cyclone is now north
of Topeka, with a corridor of 3-5 mb 2-hourly surface pressure falls
along a developing warm frontal zone to its east shifting
east-northeastward across northern Missouri.  This is occurring in
advance of consolidating, larger-scale mid-level troughing forecast
to progress east of the the Colorado Rockies into the central Great
Plains by 11/00Z.  This is preceded by a short wave perturbation of
subtropical eastern Pacific origin, which appears to still include
one prominent mid-level cyclonic vorticity center approaching the
Kansas City area.

It appears that the stronger forcing for ascent associated with the
cyclonic vorticity center will progress east-northeast of the Kansas
City area, before substantive boundary-layer destabilization can
take place.  However, models suggest that a narrow corridor of at
least modest, but deepening, boundary layer moisture is possible
along a 50-60+ kt southwesterly pre-frontal 850 mb jet axis across
western through northern Missouri.  As the surface warm frontal zone
continues to advance north of the Missouri River/Interstate 70
corridor, the environment along it might become conducive to
isolated strong to severe storm development prior to 11/00Z,
particularly south of Chillicothe into areas southeast of
Kirksville.

Even with some moistening, relatively warm mid-level temperatures
may tend to minimize mixed-layer CAPE, but beneath 90-100 kt
southwesterly 500 mb flow, hodographs are forecast to become
favorable for supercells potentially accompanied by a risk for
producing tornadoes.

..Kerr/Thompson.. 12/10/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LSX...DVN...SGF...EAX...

LAT...LON   39889333 40579133 39709124 39329135 38859228 38509349
            39009388 39889333

Mesoscale Discussions in Missouri, 2021Every mesoscale discussion in 2021

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.