Mesoscale Discussion 710

Issued

May 7, 2023, 2:10 PM CDT (19:10 UTC)

Expired

May 7, 2023, 4:15 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch likely

Chance of a watch

80%

The Des Moines radar (KDMX), 37 km from the middle of the area, began a volume at 19:12 UTC, the scan nearest the moment this went out.

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• Severe Thunderstorm Watch 198May 7, 4:10 PM CDT

145 
ACUS11 KWNS 071911
SWOMCD
SPC MCD 071910 
IAZ000-NEZ000-072115-

Mesoscale Discussion 0710
NWS Storm Prediction Center Norman OK
0210 PM CDT Sun May 07 2023

Areas affected...far east-central Nebraska into central/southern
Iowa

Concerning...Severe potential...Watch likely 

Valid 071910Z - 072115Z

Probability of Watch Issuance...80 percent

SUMMARY...Isolated large hail may accompany an intense cell tracking
east across central Iowa over the next couple of hours. Additional,
more widespread storms are expected later this afternoon/evening. A
watch will likely be needed at some point later this afternoon, but
timing remains uncertain.

DISCUSSION...An isolated, severe thunderstorm has been tracking
eastward along a surface boundary with the stronger instability
gradient over central IA. Marginally severe hail has been reported
with this storm recently over Carroll County. This cell may continue
to periodically produce large hail and gusty winds as it shifts
eastward along the surface boundary.

Additional thunderstorm development is expected later this afternoon
or early evening as a surface low over southeast NE lifts northeast
toward the MO River over the next few hours. Various surface fronts
and outflow boundaries exist across the area, providing potential
points of focus for thunderstorm development. Strong heating and
dewpoints in the low/mid 60s beneath steep midlevel lapse rates is
resulting in moderate destabilization from east-central NE into
southern IA. While some capping is still evident near the MO River
into southwest IA as depicted by billow clouds on visible satellite,
erosion of the cap is more evident further east toward southeast IA
where deepening cumulus is noted. Additional heating and increasing
ascent later today will support rapid thunderstorm development.
However, timing remains a bit uncertain. Hi-res CAMs suggest later
development closer to 00z, however observational trends suggest
early convective initiation may be possible. 

Backed low-level flow and increasing 850 mb southwesterly flow with
time will support enlarged, favorably curved low-level hodographs. A
few tornadoes, in addition to large hail and damaging gusts will be
possible. A watch will likely be needed at some point this afternoon
(most likely by 21-23z).

..Leitman/Hart.. 05/07/2023

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

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

LAT...LON   41679134 41289115 40789134 40679162 40679239 40609487
            40649593 40799639 41119686 41479683 41899649 42129591
            42319524 42389390 42239285 41929159 41679134

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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.