Mesoscale Discussion 1237

Issued

Jun 24, 2023, 2:43 AM CDT (07:43 UTC)

Expired

Jun 24, 2023, 4:45 AM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch likely

Chance of a watch

80%

Counties Harrison County, IA, Mills County, IA, Monona County, IA, Plymouth County, IA, Pottawattamie County, IA, Woodbury County, IA, Burt County, NE, Cass County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Lancaster County, NE, Otoe County, NE, Sarpy County, NE, Saunders County, NE, Thurston County, NE, Washington County, NE, Union County, SD

The Omaha radar (KOAX), 62 km from the middle of the area, began a volume at 07:46 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.

• Severe Thunderstorm Watch 369Jun 24, 3:10 AM CDT

930 
ACUS11 KWNS 240743
SWOMCD
SPC MCD 240743 
IAZ000-MOZ000-NEZ000-SDZ000-240945-

Mesoscale Discussion 1237
NWS Storm Prediction Center Norman OK
0243 AM CDT Sat Jun 24 2023

Areas affected...Far Eastern NE...Far Western IA

Concerning...Severe potential...Watch likely 

Valid 240743Z - 240945Z

Probability of Watch Issuance...80 percent

SUMMARY...Damaging gusts are possible across the Mid MO River Valley
when the ongoing convective line moves through late this morning. A
Severe Thunderstorm Watch will be needed across portions of the
region to cover this threat.

DISCUSSION...Ongoing convective line has shown a trend toward more
cold-pool organization over the last hour or so, with the line now
oriented north-south from about 25 miles north-northwest of ONL to
ODX. The immediate downstream air mass across much of eastern NE has
ample low-level moisture to support the continuation of this
convective line. Current conditions within airmass farther east
across the Mid MO Valley are not as moist as those across much of
eastern NE, with dewpoints in the low 60s in the immediate vicinity
of the MO River. However, low-level moisture advection is expected
to continue as the warm front draped from northwest to southeast
across the region progresses northeastward. 

This increase in low-level moisture coupled with the persistent
low-level jet will likely lead to a modest increase in buoyancy
ahead of the approaching convective line. Given the current speed of
the ongoing line, it will likely outrun the low-level moisture
return as it moves into IA. However, before this occurs, severe
thunderstorms capable of damaging gusts are possible as the line
moves through the Mid MO River Valley. Consequently, a watch will
likely be needed across portions of the region to cover this threat.

..Mosier/Edwards.. 06/24/2023

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

ATTN...WFO...DMX...EAX...FSD...OAX...

LAT...LON   42349699 42879675 42789589 41679544 40539569 40629676
            42349699

Mesoscale Discussions in Nebraska, 2023Mesoscale Discussions in Iowa, 2023Mesoscale Discussions in South Dakota, 2023Every mesoscale discussion in 2023

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.