SPC MD 2250

SPC MD 2250


Mesoscale Discussion 2250
NWS Storm Prediction Center Norman OK
1212 PM CDT Fri Oct 13 2023

Areas affected…Parts of central IA

Concerning…Severe potential…Watch possible

Valid 131712Z – 131845Z

Probability of Watch Issuance…40 percent

SUMMARY…A few brief tornadoes and isolated hail are possible this

DISCUSSION…A deep-layer cyclone currently centered near the IA/NE
border will move eastward across western/central this afternoon. A
surface front extends northeastward from the low into northwest IA,
then arcs southeastward across central IA into northern MO.
Widespread cloudiness is noted along/ahead of the front, though some
thinning and cloud breaks have recently developed across parts of
north-central and south-central IA.

As pre-frontal temperatures warm through the 60s F within a modestly
moist boundary layer, MLCAPE will increase into the 300-700 J/kg
range. Weak convection has already developed in Pocahontas County,
with additional development expected by early/mid afternoon
southward along the frontal boundary. A band of storms is expected
to evolve by mid afternoon, with modestly favorable effective shear
(generally 30-35 kt) potentially supporting embedded supercell
structures, especially from central into south-central IA.

A combination of modestly favorable low-level shear/SRH and ambient
vertical vorticity associated with the cyclone will support a threat
of a few brief tornadoes this afternoon, both within a
hybrid/marginal supercell environment across central/south-central
IA, and a landspout environment into parts of
north-central/northwest IA. Cool temperatures aloft may also support
isolated hail with the strongest storms. While coverage and
magnitude of the threat may remain relatively limited, tornado watch
issuance is possible this afternoon if confidence in the potential
for multiple tornadoes increases.

..Dean/Thompson.. 10/13/2023

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


LAT…LON 42619475 42959474 42939397 42269255 41609231 40939237
40939268 41049319 41499361 41829388 42259436 42619475

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