Subj : MESO: Mesoscale Discussion 1501
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sun Jun 29 2025 03:02:54

ACUS11 KWNS 290301
SWOMCD
SPC MCD 290301=20
SDZ000-NEZ000-290500-

Mesoscale Discussion 1501
NWS Storm Prediction Center Norman OK
1001 PM CDT Sat Jun 28 2025

Areas affected...Southern South Dakota and northern Nebraska

Concerning...Severe potential...Watch possible=20

Valid 290301Z - 290500Z

Probability of Watch Issuance...40 percent

SUMMARY...Thunderstorms will increase overnight near the
Nebraska/South Dakota border.  If sufficient clustering of
convection occurs, then there will be the potential for severe
outflow gusts and a watch may need to be considered by about 04-05z.

DISCUSSION...An earlier supercell has dissipated across south
central SD, but new convection has been forming to the west atop
outflow and a surface cold front.  As a 25-35 kt southerly low-level
jet forms, warm advection atop the frontal surface will increase,
coincident with an increase in midlevel moisture from the west that
is related to earlier high-based convection in WY/NE Panhandle.=20
This scenario will favor an increase in elevated convection near the
NE/SD border through the overnight hours.  Though this corridor is
along the southern edge of the midlevel westerlies, midlevel lapse
rates remain very steep (8.5 C/km or greater) and profiles will
still be favorable for both strong updrafts and downdrafts.  If
sufficient clustering of storms can occur, then there will be some
concern for severe outflow gusts and isolated large hail, and the
conditional potential for a severe thunderstorm watch by roughly
04-05z.

...Thompson/Guyer.. 06/29/2025

....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj=
g!4iOvvYen3rgFwE3CLGuMl-AwLPR1mcBFk4LZuAxgWnhaoKJhtBTMbJePdsAaRwqrFmv-AojFc=
URh1kPUt85PmCmR1Sk$  for graphic product...

ATTN...WFO...FSD...ABR...LBF...UNR...

LAT...LON   42479905 42470128 42620221 43140229 43320186 43610026
            43649893 43239857 42749870 42479905=20

MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


=3D =3D =3D
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