Mesoscale Discussion 1820

Issued

Oct 10, 2021, 2:04 PM CDT (19:04 UTC)

Expired

Oct 10, 2021, 4:00 PM CDT

In force

116 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch likely

Chance of a watch

80%

Counties Blaine County, OK, Caddo County, OK, Canadian County, OK, Comanche County, OK, Garfield County, OK, Grady County, OK, Greer County, OK, Harmon County, OK, Jackson County, OK, Kay County, OK, Kingfisher County, OK, Kiowa County, OK, Logan County, OK, Noble County, OK, Oklahoma County, OK, Pawnee County, OK, Payne County, OK, Tillman County, OK, Washita County, OK, Wilbarger County, TX

The Altus AFB radar (KFDR), 115 km from the middle of the area, began a volume at 19:08 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 517Oct 10, 3:20 PM CDT

829 
ACUS11 KWNS 101905
SWOMCD
SPC MCD 101904 
OKZ000-KSZ000-TXZ000-102100-

Mesoscale Discussion 1820
NWS Storm Prediction Center Norman OK
0204 PM CDT Sun Oct 10 2021

Areas affected...Parts of southwestern through north central
Oklahoma and adjacent portions of northwest Texas and south central
Kansas

Concerning...Severe potential...Watch likely 

Valid 101904Z - 102100Z

Probability of Watch Issuance...80 percent

SUMMARY...Increasingly widespread and intensifying thunderstorm
development appears probable in a corridor across southwestern
through north central Oklahoma, including the Greater Oklahoma City
area, as well as adjacent portions of northwest Texas and south
central Kansas, by 5-7 PM.  Some of this activity will pose a risk
for severe hail initially, with increasing potential for a few
tornadoes by early evening.

DISCUSSION...A weak surface cold front has stalled south of Wichita,
KS, south-southwestward into areas near/east of Childress, TX, where
a surface low is beginning to form near the nose of a corridor of
stronger boundary-layer heating and deeper mixing, beneath a plume
of capping elevated mixed-layer air across the southern Great
Plains.  A dryline is becoming better defined east and south of the
surface low, and boundary-layer moisture is gradually increasing
along and ahead of the front to the northeast of the surface low.

Due to the initially modest moisture relatively to the warmth of the
elevated mixed-layer, latest objective analysis indicates that warm
sector boundary-layer CAPE remains fairly weak (500-1000 J/kg). 
However, it appears that this will begin to substantively change
during the next few hours, as the leading edge of mid-level forcing
for ascent and cooling now overspreading the Texas Panhandle/South
Plains progresses eastward.

Weakening inhibition and increasing mixed-layer CAPE likely will
coincide with strengthening deep-layer shear accompanying a 50-70+
kt southwesterly 500 mb jet streak, contributing to an environment
conducive to organized severe thunderstorm development.  It seems
probable that this will include a rapidly upscale growing line of
storms along/ahead of the front by early evening.  However, initial
storm development may include isolated to scattered discrete
supercells, particularly in a possible cluster near/northeast of the
surface low and dryline across southwestern Oklahoma.

South-southwesterly flow in the 850-700 mb layer is initially rather
modest, but forecast to strengthen to 30-40+ in the vicinity of the
intensifying convective development, generally along the Interstate
44 and 35 corridors (near and southwest through north of the
Oklahoma City metropolitan area) by around 00-01Z.  This will
contribute to enlarging low-level hodographs supportive of
strengthening low-level mesocyclones, posing a risk for tornadoes,
in addition to severe hail.

..Kerr/Hart.. 10/10/2021

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

ATTN...WFO...TSA...ICT...OUN...LUB...

LAT...LON   35069977 35839849 37299712 36439647 34669803 33959908
            34490009 35069977

Mesoscale Discussions in Oklahoma, 2021Mesoscale Discussions in Texas, 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.