They've increased the chances of nasty storms since this morning.
NWS Storm Prediction Center Norman OK
1240 PM CDT Tue Oct 29 2024
Valid 301200Z - 311200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF NORTHWESTERN MISSOURI...EASTERN KANSAS...AND NORTHEASTERN
OKLAHOMA...
...SUMMARY...
Strong/severe thunderstorms, capable of producing large hail,
damaging wind gusts, and a few tornadoes, are expected on Wednesday
across central portions of the country -- particularly from the
middle Missouri Valley area southward to North Texas.
...Synopsis...
An upper trough initially aligned across the interior West will
progress east-northeastward out of the Rockies and into the Plains
during the afternoon and evening, and then will continue onward
toward/into the Mid- and Upper-Mississippi Valley area overnight.
At the surface, a cold front will initially extend
northeast-to-southwest across the central U.S. -- from the Lake
Superior vicinity southwestward to southeastern New Mexico and Far
West Texas. This front will make only gradual eastward progress
initially, as a frontal wave develops in the southeastern Kansas
vicinity and then shifts quickly northeastward along the baroclinic
zone through the day -- to a position near Topeka around sunset.
From there, as the low deepens and progresses toward Wisconsin, the
trailing cold front will begin to surge more quickly
eastward/southeastward, and should extend across central Illinois,
southeastern Missouri, Arkansas, to central Texas by Thursday
morning.
...Mid-Mississippi/Mid-Missouri Valleys across northeastern Texas...
As the advancing upper system shifts out of the Rockies and across
the High Plains through the day, large-scale ascent -- focused near
the cold front -- will gradually increase. Ahead of the front, a
moist (60s dewpoints) airmass will be in place along/ahead of the
front across the central/southern Plains, and should spread
northward across Iowa and into Wisconsin through the day. This,
combined with daytime heating and modestly steep lapse rates aloft,
will allow gradual/steady destabilization to occur through the
morning and afternoon hours.
Initial storm development is forecast by mid to late morning, in the
eastern Nebraska/northeastern Kansas/western Iowa vicinity, and then
expanding northeastward toward the upper Mississippi Valley, and
southward across eastern Kansas, through the afternoon.
In addition to the amply unstable environment that will be evolving
(mixed-layer CAPE in the 1000 to 1500 J/kg range), increasingly
favorable shear will also evolve with time. This will occur as
mid-level southwesterly flow associated with the advancing upper
system spreads eastward across the central Plains, atop low-level
southerly flow near/ahead of the forecast track of the frontal low.
The resulting wind field -- veering favorably and increasing in
speed with height through the lowest half of the troposphere -- will
support supercells. It appears that convection should remain at
least somewhat cellular through the daylight hours from the
Topeka/Kansas City vicinity southward, which would correspond with
risk for a few tornadoes, along with large hail and damaging wind
potential.
Farther to the northeast, across Iowa and into Wisconsin, risk
should remain lower, given lesser instability. Overall, storms
should gradually grow upscale linearly, and will shift eastward with
time across Iowa and into Missouri -- and eventually Illinois
overnight, accompanied by at least limited severe risk into the
overnight hours.
Farther south into Oklahoma and Texas, storm development should
occur later, likely not until after dark. Still, with the
thermodynamic and kinematic environment favoring rotating storms,
the all-hazards severe risk should expand southward across Oklahoma
and into northern and possibly central Texas. With time, storms
should grow upscale linearly across this region as well, after the
initial/primarily cellular mode. Like areas farther north, at least
some severe risk should continue overnight, spreading eastward into
Arkansas and East Texas with time.
..Goss.. 10/29/2024