Mesoscale Discussion 1092

Issued

Jun 25, 2021, 1:00 PM CDT (18:00 UTC)

Expired

Jun 25, 2021, 3:00 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

5%

The Des Moines radar (KDMX), 46 km from the middle of the area, began a volume at 18:01 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

835 
ACUS11 KWNS 251800
SWOMCD
SPC MCD 251800 
ILZ000-IAZ000-NEZ000-252000-

Mesoscale Discussion 1092
NWS Storm Prediction Center Norman OK
0100 PM CDT Fri Jun 25 2021

Areas affected...Western to central Iowa

Concerning...Severe potential...Watch unlikely 

Valid 251800Z - 252000Z

Probability of Watch Issuance...5 percent

SUMMARY...Thunderstorms will increase in coverage along an effective
warm front through mid-afternoon. A few storms may be strong to
severe and pose a brief hail and damaging wind threat. A watch is
not expected.

DISCUSSION...Recent GOES imagery shows convective towers attempting
to deepen along an effective warm frontal boundary across IA. While
most towers have shown only transient intensification, more robust
convective initiation appears underway across western IA. As
destabilization continues through the early afternoon hours
sustained convection will become more likely along the front. A
pocket of richer boundary-layer moisture with dewpoints in the 70s
is supporting MLCAPE values near 1000-1500 J/kg with minimal
inhibition. Despite favorable instability, deep-layer flow is
somewhat weak with only 15-25 knots of effective bulk shear over the
region (per recent mesoanalysis estimates). Mean flow over the
region is also oriented largely along the boundary, suggesting that
clusters with numerous storm interactions are likely. As such, the
potential for robust and long-lived severe thunderstorms appears low
and precludes the need for a watch. That said, brief hail threats
may evolve with any stronger updraft pulses, and damaging down burst
winds are possible.

..Moore/Guyer.. 06/25/2021

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

ATTN...WFO...DVN...ARX...DMX...FSD...OAX...

LAT...LON   42519624 42879560 42949423 42809273 42409113 41889018
            41489036 41509146 41609252 41699355 41859478 41889572
            41999618 42519624

Mesoscale Discussions in Iowa, 2021Every mesoscale discussion in 2021

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.