Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
901 PM EDT Sat Apr 19 2025
Day 1
Valid 01Z Sun Apr 20 2025 - 12Z Sun Apr 20 2025

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FROM NORTH-
CENTRAL TEXAS THROUGH NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS...

...0100Z Update...
Changes made to the Day 1 ERO, most notably the Slight and
Moderate Risk areas, were based on the more recent HRRR and WoFS
trends this evening. In particular, given the mid-upper trough
amplification over the southern Rockies-High Plains, the orientation
of both the Moderate and Slight Risk areas, particularly the western
edges, were tilted more N-S. Again this was based in particular
over the latest several HRRR runs (21/22/23Z), along with recent
WoFS runs.

Hurley


...Previous Discussion...

A narrow corridor of 4 to 6+ inches of rainfall likely today
across southern Missouri to North-central Texas as thunderstorms
train and backbuild along a slow moving/stalled frontal boundary.
There has been a consistent and persistent westward trend of the
placement of the heaviest rainfall both in the model runs and the
deterministic WPC QPF. Once again the risk areas were expanded
south and west. The Moderate Risk spans from north-central Texas to
the Missouri Ozarks; which had a minor reduction in coverage out of
Illinois given the decrease in QPF from the Mid-Mississippi Valley
to Ohio. The Slight Risk was also reduced over parts of Illinois
and Indiana while extended further into central Texas. The Marginal
was trimmed southward across Illinois, Indiana and Ohio while
adjusted westward of west-central Texas.

On the north side the cold, dry northeasterly flow will be
weakening while in the warm sector there will be an ever increasing
supply of hot and humid air straight out of the Gulf being
advected northward on up to 50 kt winds across Texas and into the
frontal interface from north Texas through Oklahoma and Missouri.
An upper low ejecting from the mountains into this hot, moist
airmass will lead to robust cyclogenesis over Oklahoma by Sunday
morning.

Campbell


Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt