SPC MD 390

MD 0390 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHERN/CENTRAL IA...FAR EAST-CENTRAL NE...FAR NORTHWEST IL

Mesoscale Discussion 0390
NWS Storm Prediction Center Norman OK
0104 AM CDT Sat May 12 2018

Areas affected...Southern/central IA...Far east-central NE...Far
northwest IL

Concerning...Severe potential...Watch unlikely 

Valid 120604Z - 120800Z

Probability of Watch Issuance...5 percent

SUMMARY...Isolated hail is possible across the region over the next
few hours.

DISCUSSION...Thunderstorm coverage has increased over the past hour
as a strengthening low-level jet and resulting warm-air advection
across the frontal zone lifts parcels to their LFC. Recent
mesoanalysis estimates effective shear around 40 to 50 kt amidst
MUCAPE near 1000-1500 J/kg. Given these factors, predominant storm
mode is expected to be multicells with only loosely organized
updrafts. Hail will be possible with the stronger storms and as a
result of cell interactions/mergers. The stable boundary layer in
place should preclude any damaging wind gusts. Isolated and marginal
nature of the severe threat will likely preclude the need for a
watch.

..Mosier/Edwards.. 05/12/2018

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

ATTN...WFO...DVN...DMX...OAX...

LAT...LON   40999646 41669628 42239480 42369188 42089033 41289012
            41229130 41149319 40889459 40649585 40999646 

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from SPC Forecast Products http://www.spc.noaa.gov/products/md/md0390.html