095
ACUS11 KWNS 211051
SWOMCD
SPC MCD 211051
IAZ000-MOZ000-NEZ000-211245-

Mesoscale Discussion 0867
NWS Storm Prediction Center Norman OK
0551 AM CDT Tue May 21 2024

Areas affected...eastern Nebraska eastward across southwestern and
south-central Iowa

Concerning...Severe Thunderstorm Watch 274...

Valid 211051Z - 211245Z

The severe weather threat for Severe Thunderstorm Watch 274
continues.

SUMMARY...Severe risk -- mainly in the form of locally damaging wind
gusts -- will continue spreading eastward across eastern Nebraska
and into southwestern Iowa over the next couple of hours.  New WW
issuance across southwestern and south-central Iowa will likely be
required.

DISCUSSION...Latest radar loop shows an organized/bowing north-south
band of storms moving quickly eastward across eastern Nebraska at
around 50 kt.  Meanwhile, a more-loosely organized, west-to-east
band of convection, on the cool side of a front/outflow composite
boundary lying west-to-east across central portions of Iowa,
continues to make slow southward progress.  North of this
west-to-east convective band, widespread rain has substantially
stabilized the lowest levels of the troposphere, with temperatures
in the low 60s and dewpoints near 60 across central and northern
Iowa.  As such, little potential for surface-based severe weather
appears to exist north of this convective band.  As the northern
portion of the strong/severe convective arc over eastern Nebraska
continues moving northeastward, eventually shifting atop this cooler
air, weakening of this convection  -- at least in terms of severe
risk -- is anticipated.

With that said, portions of the Nebraska bow moving more eastward
toward the Omaha area and areas south, will remain near/south of the
west-to-east Iowa surface boundary.  It is across this corridor --
i.e. roughly the southern third of Iowa -- where severe risk is
expected to persist longer into the morning hours.  As storms
approach eastern fringes of WW 274, a new WW will likely therefore
be required across southern Iowa.

..Goss.. 05/21/2024

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

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

LAT...LON   41409669 41969684 42039287 42289157 41399154 40709243
            40359580 40559682 41409669