Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
419 AM EDT Sat May 18 2024
Day 2
Valid 12Z Mon May 20 2024 - 12Z Tue May 21 2024

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE CENTRAL PLAINS/CORN BELT...

Broad SW flow over the central Plains across the Corn Belt will
bring in increasing moisture to the region on Sunday with a surface
frontal boundary hung up over Iowa. Mid-level vorticity will exit
the central Rockies and moves across the central Plains as
precipitable water values rise to around 1.50" (+1.5-2 sigma) with
some instability in the afternoon/early evening (500-2000J/kg) that
could yield some 1"/hr rates (per 00Z HREF thru 00Z Mon) which are
near FFG values over Iowa and nearby areas. The region has been
fairly dry the past week (most of the region has had about 50% of
the normal rainfall) so much of the rain will be beneficial, but
given 1-hr FFG values near 1"/hr (between MCI-OMA- DSM), maintained
the Marginal Risk outline for the region. Higher probabilities
exist farther southwest into central Kansas (to where the Marginal
was extended), but FFG values are higher as well (2"/hr). 12Z CAM
guidance through 12Z Mon may shed a little more light on the higher
rainfall potential over the entire 24 hours.


Fracasso