MD 1239 CONCERNING SEVERE POTENTIAL…TORNADO WATCH LIKELY FOR PORTIONS OF WESTERN AND CENTRAL IOWA
Mesoscale Discussion 1239
NWS Storm Prediction Center Norman OK
0127 PM CDT Sat Jun 24 2023
Areas affected...Portions of western and central Iowa
Concerning...Severe potential...Tornado Watch likely
Valid 241827Z - 242030Z
Probability of Watch Issuance...95 percent
SUMMARY...The threat for large hail, a couple of tornadoes, and
damaging winds will increase this afternoon. A tornado watch is
likely for parts of central and eastern Iowa soon.
DISCUSSION...Morning convection across central/eastern Iowa has
generally diminished over the last couple of hours.
Warm-advection-induced convection over the outflow from this
activity has been ongoing this morning as well. Northwest of Des
Moines, a storms has slowly intensified over the past 30-45 minutes
an appears capable of producing large hail. The conditions ahead of
this storm are still cool enough that large hail and isolated
damaging winds would be the main threats. That being said,
temperatures have been rising within the outflow, particularly for
parts of central/southern Iowa. With backed surface winds and strong
low-level veering (confirmed by the KDMX VAD), there will be some
potential for a couple of tornadoes with additional convection that
can develop this afternoon. Farther north into northern Iowa,
surface winds are less backed and destabilization of the outflow may
take more time due to lingering cloud cover. Apart from the tornado
threat, strong shear and sufficient mid-level lapse rates would
support a threat for large hail (perhaps up to 2 inches). With time
and veering of the low-level winds, some upscale growth into a
cluster or two is possible. At that time, greater potential for
damaging winds would develop. A tornado watch is likely to be
considered for at least parts of central and eastern Iowa soon.
..Wendt/Grams.. 06/24/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DVN...ARX...DMX...FSD...OAX...
LAT...LON 40649381 41009462 41359511 41899535 42149542 42869525
43349454 43479321 43219237 42549200 41379215 40849231
40699257 40639288 40599334 40649381
