SPC MD 1549

MD 1549 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL TO NORTHERN IOWA

Mesoscale Discussion 1549
NWS Storm Prediction Center Norman OK
0657 PM CDT Sat Aug 22 2020

Areas affected...Central to northern Iowa

Concerning...Severe potential...Watch unlikely 

Valid 222357Z - 230130Z

Probability of Watch Issuance...5 percent

SUMMARY...Developing thunderstorms may pose a risk for hail and wind
over the next one to two hours, but the threat should remain limited
in coverage and duration. A watch is not expected.

DISCUSSION...Recent visible satellite and KDMX radar imagery show
developing thunderstorms within a diffuse confluence zone in the
vicinity of a weak surface low. These storms are forming within a
moderately unstable air mass (2000-2500 J/kg MLCAPE) with around 35
knots of effective bulk wind shear normal to the initiating
boundaries. This environment is sufficient for supporting discrete,
organized convection that could pose a severe hail and wind threat
over the next one to two hours. However, lift across this region is
fairly weak and may struggle to sustain long-lived convection.
Additionally, the onset of diurnal cooling/increasing inhibition
after sunset casts uncertainty into the longevity of these storms
after 01 UTC. These concerns, coupled with the isolated nature of
the threat preclude the need for a watch.

..Moore/Grams.. 08/22/2020

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

ATTN...WFO...DMX...FSD...

LAT...LON   42869514 42939405 42669306 42119293 41579328 41539390
            41749475 42159507 42629514 42869514 

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