Subj : MESO: Mesoscale Discussion 1951
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Fri Aug 15 2025 16:53:05

ACUS11 KWNS 151652
SWOMCD
SPC MCD 151651=20
IAZ000-151845-

Mesoscale Discussion 1951
NWS Storm Prediction Center Norman OK
1151 AM CDT Fri Aug 15 2025

Areas affected...northern/central IA

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

Valid 151651Z - 151845Z

Probability of Watch Issuance...60 percent

SUMMARY...The severe hail and wind threat may increase this
afternoon across northern and central Iowa with low forecast
confidence on both coverage/intensity. A Severe Thunderstorm Watch
issuance is possible.

DISCUSSION...As alluded to in the 1630Z SWODY1, short-term forecast
confidence is low with regard to a long-lived but small cluster over
northwest IA. This had diminished for a time after earlier supercell
evolution in northeast NE, but appears to be oscillating up/down
again with some development flanking to its southwest. Gravity waves
emanating from this cluster aided in elevated convective development
downstream in west-central IA with cloud bases near 10k ft. These
updrafts appear to have pulsed back down and may lack
sustainability.=20

In addition to the weak large-scale ascent, modest deep-layer shear
may limit substantial organization unless a more pronounced cold
pool develops. This could occur towards late afternoon if convective
coverage indeed increases surrounding the confined cluster. Morning
CAM guidance varies greatly from nil convection in the HRRR to an
enlarging cluster and MCS development. For now, the most likely
scenario is for an isolated severe hail/wind threat but with a wide
range of potential scenarios into the late afternoon.

...Grams/Mosier.. 08/15/2025

....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj=
g!_cw924plQhurx5YTioKUyCQ41t5t0ML5K1pQ_482KuWvj_9N0xK5CLCN1EuSt5uZ8JmDlMl5m=
QbsNtbjtlIlSwDqXFM$  for graphic product...

ATTN...WFO...DVN...ARX...DMX...FSD...

LAT...LON   42889553 43239518 43439437 43369245 43179192 42789181
            42419187 42009201 41639244 41589348 41789462 41999539
            42319569 42889553=20

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


=3D =3D =3D
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