Subj : MESO: Mesoscale Discussion 1437
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Wed Jun 25 2025 19:16:50

ACUS11 KWNS 251916
SWOMCD
SPC MCD 251916=20
IAZ000-NEZ000-SDZ000-252115-

Mesoscale Discussion 1437
NWS Storm Prediction Center Norman OK
0216 PM CDT Wed Jun 25 2025

Areas affected...central and northeastern Nebraska...parts of
southeastern South Dakota and northwestern Iowa

Concerning...Severe potential...Watch likely=20

Valid 251916Z - 252115Z

Probability of Watch Issuance...80 percent

SUMMARY...A corridor of increasing thunderstorm development,
including gradually organizing clusters with increasing potential
for strong to severe surface gusts, through 4-6 PM CDT.

DISCUSSION...In the wake of one low-amplitude short-wavelength
perturbation migrating through the Upper Midwest toward adjacent
Great Lakes vicinity, a similar strength perturbation is gradually
migrating north-northeastward through the central high plains,
around the northwestern periphery of the prominent mid-level ridge
centered over the Tennessee Valley.  Downstream of this feature,
forcing for ascent has maintained an arcing band of precipitation
across Nebraska, which is preceded by a seasonably high moisture
content boundary-layer that is destabilizing beneath relatively warm
and dry layers aloft associated with the ridging.

Within the strengthening zone of differential surface heating to the
east of the precipitation band, mixed-layer CAPE is beginning to
increase in excess of 2000 J/kg, beneath a modest belt of
southwesterly mid-level flow which includes speeds of 30-40 kt in
the 700-500 mb layer.  Although mid/upper-level lapse rates are
weak, as low-level lapse rates continue to steepen and inhibition
erodes further, a corridor of increasing thunderstorm development
appears probable across Nebraska, from the Lexington NE toward Sioux
City IA vicinity, through 21-23Z.  As this occurs, heavy
precipitation loading and evaporative cooling in downdrafts may
gradually contribute to downward momentum transfer accompanied by
increasing potential for a few strong to severe severe gusts, in
slowly organizing clusters.

...Kerr/Hart.. 06/25/2025

....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj=
g!6r7URrfFvdB-TcFccmEVG3z9PmgsHWivHAGximkZgwph_h0QX20EdD36HbuiHVJm3QUOQck0t=
kywSipz6yCcGI5LaCU$  for graphic product...

ATTN...WFO...FSD...OAX...GID...LBF...GLD...

LAT...LON   42469828 43059711 43359625 42259575 40399842 40059932
            40200042 41260011 42469828=20

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


=3D =3D =3D
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