Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
550 AM EDT Thu Jul 16 2026
Day 2
Valid 12Z Fri Jul 17 2026 - 12Z Sat Jul 18 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS MUCH OF WEST
TEXAS, SOUTHERN NEW MEXICO, ARIZONA, AND THE SOUTHERN GREAT
BASIN...

...West Texas into Southern New Mexico...

A transition and decay in the high-impact heavy rain setup across
the Edwards Plateau and southern Hill Country is expected as the
mid-level trough over West Texas weakens and begins to dissolve.
However, despite the trend, lingering elevated moisture beneath the
lower height field will allow for scattered activity, mostly
northwest of the areas most severely impacted earlier in the week.

While the general forecast totals are lower than previous days,
localized heavy rates may result in additional concerns, especially
in areas left vulnerable by prior rounds of heavy rainfall.

In southern New Mexico, storms are expected to develop along and
near the Sacramento Mountains by the afternoon and continue into
the evening before diminishing with the loss of diurnal heating.
Active wildfire burn scars in this region make it particularly
susceptible to rapid runoffs, supporting the continuation of the
Slight Risk.

...Western U.S./Great Basin...

Overall, only minor changes were made to the risk areas in the
West, as a persistent monsoonal pattern remains locked in place.
A robust moisture profile will sustain widespread convective
coverage from southern Arizona north-northeastward into the Great
Basin. Moisture anomalies will remain high, with standardized
anomalies of 2-3 extending all the way from the Southwest to the
northern Rockies.

This moisture, along with with sufficient instability will support
highly efficient rainfall rates. A broad Slight Risk was maintained
from southern Arizona to southern Utah, with complex terrain,
urbanized areas, and other vulnerable areas likely to a be a focus
for the greater runoff concerns across the region.

...Ohio/Tennessee Valleys into the Central and Southern
Appalachians....

A Marginal Risk covering much of the Ohio and Tennessee Valleys
into the central and southern Appalachians was maintained. Storms
developing across this region will be fueled by the same high-PW
airmass noted in the Day 1 period as it spread farther north and
east. These diurnally-driven storms are once again expected to
raise isolated runoff concerns.

...Northern Great Lakes...

A progressive upper trough digging southeast across central Canada,
will shift a notable jet max south into northern Minnesota. Strong
low level convergence along with favorable upper jet forcing will
support nocturnal storms from the Minnesota Arrowhead eastward into
Upper Michigan. Although fast storm motions will the heavy
accumulation and flash flooding threat, anomalous moisture
supporting heavy rates, along with some potential for brief
training, may raise isolated concerns.

Pereira


Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt