SPC Mar 18, 2025 1300 UTC Day 1 Convective Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0739 AM CDT Tue Mar 18 2025

Valid 181300Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE TONIGHT
FROM EASTERN NE INTO IA...

...SUMMARY...
Isolated, marginally severe hail is possible late tonight from
eastern Nebraska across much of Iowa.

...Eastern NE/IA late tonight and early Wednesday...
In advance of a pronounced midlevel shortwave trough over
UT/northern AZ this morning, a surface lee cyclone will deepen
across western KS and then move to far northwest MO by early
Wednesday.  Moisture return in the warm sector of this deepening
cyclone will be limited by a prior frontal passage across the
Gulf/northwest Caribbean, with only a narrow corridor of low-mid 50s
boundary-layer dewpoints expected from eastern OK to far northwest
MO.  Though the warm sector will remain capped through the period,
there could be sufficient ascent/moistening for elevated
thunderstorm development by 06-12z from eastern NE across IA.  Steep
midlevel lapse rates and relatively cold midlevel temperatures will
contribute to MUCAPE of 500-750 J/kg and the potential for isolated
large hail (a few instances near 1 inch diameter) with elevated
convection to the cool side of a baroclinic zone across eastern
NE/IA.

..Thompson/Dean.. 03/18/2025

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