Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
848 PM EDT Sat May 4 2024
Day 1
Valid 01Z Sun May 05 2024 - 12Z Sun May 05 2024

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL TODAY AND TONIGHT
ACROSS PORTIONS OF THE SOUTHERN PLAINS...

..Southern Plains and Gulf Coast...

...01000 UTC Update...
Minor adjustments were made to the outlook areas across TX-OK-AR
based on the latest observational and mesoanalysis trends along
with the latest HRRR and 18Z HREF guidance. Convection continues to
grow upscale this evening across central-western TX. Consensus
still favors the highest amounts to focus near the Texas Hill
country and surrounding locations to the immediate east and north.
Hi-res guidance is showing several hours where the hourly rainfall
rates will be 2-2.5 inches/hr with a couple instances where it
surges to 3-4 inches/hr. The latest (18Z) HREF indicated peak probs
(60-70%) of >2"/hr rainfall rates between 02-06Z, while >3"/hr
rates peak between 30-35%.

Hurley

...Previous Discussion...
The focus of attention becomes the Southern Plains as a mid- and
upper level trough emerges from the southern Rockies later today
and encounters an atmosphere becoming increasingly moist and
unstable over much of Texas given persistent flow off the Gulf of
Mexico. The general consensus of guidance opinion is that storms
will be forming along the dry line in West Texas and then develop
upscale and towards the east in central Texas. As the storms
develop, there will be cell mergers and other interactions, as well
as possible training that could lead to local rainfall totals to 5
inches. In addition...soils in this area have been saturated due
to rainfall from thunderstorms as recent as yesterday. Thus, the
Slight Risk area was expanded south to include much of central
Texas. The surrounding Marginal was expanded further south to
account for likely guidance changes prior to the event. Most of the
flash flood producing rainfall is expected overnight tonight/early
Sunday morning with a gradual northward and eastward expansion
across the Plains. Also made an expansion of the Slight Risk
southward towards southeast Texas in deference to signals from the
00Z HRRR of a complex that bows out and spreads yet more rain into
the area that does not need any more late tonight/early Sunday
morning.

Bann

...Eastern Ohio and Tennessee Valleys, Appalachians, Mid-
Atlantic, and Southeast...

Based on the latest observational and guidance trends, have made
minor adjustments to the Marginal Risk area. This includes an
extension of the Marginal across southern GA and a small portion
of northern FL. For further information, please see Mesoscale
Precipitation Discussion of MPD #223.

Hurley