620
ACUS11 KWNS 172235
SWOMCD
SPC MCD 172235
NEZ000-SDZ000-180000-

Mesoscale Discussion 1307
NWS Storm Prediction Center Norman OK
0535 PM CDT Mon Jun 17 2024

Areas affected...Western into central NE...extreme southern SD

Concerning...Severe potential...Watch possible

Valid 172235Z - 180000Z

Probability of Watch Issuance...60 percent

SUMMARY...Supercell development is possible by early evening. Should
development occur, a few tornadoes, very large hail, and isolated
severe gusts will be possible.

DISCUSSION...A warm front is draped from west-central into northeast
NE late this afternoon. Near and south of the warm front, rich
low-level moisture beneath very steep midlevel lapse rates (as noted
on the 21Z LBF sounding) has resulted in strong destabilization,
with MLCAPE increasing above 3000 J/kg. Meanwhile, favorably veering
wind profiles with height (also noted on the 21Z LBF sounding) are
supporting effective shear of 35-45 kt, sufficient for supercells.
Low-level shear/SRH is already rather strong near and just north of
the warm front, and will continue to increase with time as a
southerly low-level jet intensifies into the evening.

Uncertainty remains regarding the coverage of surface-based storm
development into the early evening, given the rather strong capping
related to the very well-defined EML. However, the increasing
low-level jet may aid in development of one or two supercells near
the warm front by early evening, with some development also possible
farther south into the warmer and more well-mixed environment. Any
sustained supercells near the warm-frontal zone would pose a tornado
threat, in addition to potential for very large hail and isolated
severe gusts. Watch issuance will become increasingly probable for
parts of the area if supercell development appears imminent.

..Dean/Edwards.. 06/17/2024

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

ATTN...WFO...FSD...OAX...GID...LBF...UNR...CYS...

LAT...LON   40649991 40600163 40880195 41190218 41390248 41910291
            42130293 42450288 42730250 42990175 43060111 43100028
            43089916 42079817 41239828 40709913 40609938 40649991