Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 251800
SWOMCD
SPC MCD 251759
WIZ000-IAZ000-MNZ000-252000-

Mesoscale Discussion 0517
NWS Storm Prediction Center Norman OK
1259 PM CDT Fri May 25 2018

Areas affected...Southeast Minnesota...Northeast Iowa...southwestern
Wisconsin...west-central and central Wisconsin

Concerning...Severe potential...Watch possible

Valid 251759Z - 252000Z

Probability of Watch Issuance...40 percent

SUMMARY...A threat for severe hail and wind gusts will evolve this
afternoon as the atmosphere continues to destabilize. A WW will be
possible should convective trends warrant.

DISCUSSION...Visible satellite imagery depicts isolated convection
initiating beneath a cirrus deck along a weak differential heating
boundary aided by an approaching mid-level wave. Initial storms
should remain weak. However, trends in visible satellite imagery
indicate that the cirrus deck should depart from west to east as the
afternoon progresses. This should help destabilize the moist air
mass -- with dewpoints generally in the mid- to upper-60s -- and
yield MLCAPE values of 2000-2500 J/kg. Severe wind and hail will be
possible with the strongest storms. Some uncertainty exists with
regard to how quickly the cirrus will depart and destabilize the air
mass. Given the uncertainty, trends will be monitored for a possible
WW issuance later this afternoon.

..Wendt/Hart.. 05/25/2018

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

ATTN...WFO...GRB...MKX...DVN...DLH...ARX...MPX...DMX...

LAT...LON   44939170 45479053 45649000 45578944 45358875 44758838
            44138885 43408971 42569078 42459133 42669224 43049279
            43909274 44939170




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