ZCZC SPCSWOMCD ALL
ACUS11 KWNS 092307 
SPC MCD 092307 
IAZ000-100030-

Mesoscale Discussion 1943
NWS Storm Prediction Center Norman OK
0607 PM CDT Mon Sep 09 2019

Areas affected...Parts of central/eastern Iowa

Concerning...Tornado Watch 639...

Valid 092307Z - 100030Z

The severe weather threat for Tornado Watch 639 continues.

SUMMARY...An organized cluster of storms overspreading the region
may continue to pose a risk for potentially damaging wind gusts,
with perhaps a period with increasing tornado potential near/west
through south of Waterloo by around 7 PM CDT.

DISCUSSION...A small but organized convective system which has
evolved and recently spread northeast of the Des Moines area,
appears supported by mid-level forcing for ascent associated with a
small-scale perturbation within larger-scale troughing progressing
northeastward through the northern Plains vicinity.  Activity
appears embedded within moderate to strongly sheared 30-40 kt
southwesterly mean ambient flow, and may still be intensifying,
aided by increasing inflow of moist boundary layer air with CAPE up
to 2000-2500 J/kg.

Occasional strong surface gusts approaching or briefly exceeding
severe limits have been noted with the convective system, and this
could still increase during the next few hours.  It appears that the
evolving convective system will increasingly interact with a warm
frontal zone southwest through south of the Waterloo area by around
7 PM CDT.  As it does, larger clockwise curved low-level hodographs
may provide support for a period of increasing tornado potential.

..Kerr.. 09/09/2019

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

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

LAT...LON   42609126 42019169 41889213 41809279 41869342 42409316
            42689355 43129281 43139162 42609126 

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