Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
522 PM EDT Sun May 10 2026

Day 1
Valid 212Z Mon May 11 2026 - 12Z Mon May 11 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
CENTRAL AND NORTH TEXAS...

...21Z Update...

Issued a special (non-scheduled) update to the Day 1 ERO, based on
the latest observational and HRRR trends, along with the newly-
arriving 18Z HREF QPF exceedance probabilities. Per collaboration
with WFO EWX, we opted to pull the southern portion of the Slight
risk a bit farther south over the Lower TX Triangle, encompassing a
little bit more of South-Central TX. Strong diurnal heating across
this region downstream from the dryline (west) and main surface
front (N-NW) is continuing to boost mixed-layer CAPEs, which are
now running ~3000-3500 J/Kg per the SPC mesoanalysis. Meanwhile,
TPWs are expected to climb above normal for a while this
evening/overnight, nearing 1.75". Given the thermodynamic
environment in place, rainfall rates of 2-3 in/hr will be plausible
later this evening and overnight (esp 02-06Z), as the Slight Risk
area sees more upscale growth in concert with the DPVA/deep-layer
ascent ahead of the shortwave currently across eastern NM. Latest
CSU UFVS-verified First Guess fields support the expansion of the
Slight Risk.

Elsewhere, have trimmed the Marginal Risk area across much of OK
(now behind the front/increasing low-level stability), while also
expanding across central-eastern AR, SW TN, and into much of
central-northern MS. This expansion was also due to the growing
short-range CAM consensus, along with the 18Z HREF probabilistic
suite. For additional information regarding these areas now under
the Marginal Risk, please refer to the latest mesoscale
precipitation discussion, or MPD #167.

Hurley


...16Z Update...

The Slight Risk area was expanded a bit with this update, mostly
towards the south but also to include the rest of the DFW
Metroplex. Clusters of storms are expected to develop this
afternoon, likely as a continuation of the showers and storms
ongoing currently over Oklahoma, but developing further south into
Texas. Much of the convective activity is expected to congeal south
and west of the Metroplex, but urban concerns and some expected
development over the Metroplex still heighten the flash flooding
risk into the lower-end Slight category. Meanwhile, while
convection will be more numerous and strong further south and west,
less urban development may help to mitigate the flash flooding
threat a bit. By late evening, around 03Z/10pm CDT or so, the
convection is expected to have organized into a mostly single line
of storms that will progressively shift southeast towards the Gulf.
This should greatly mitigate the flash flooding threat by that
point and beyond. Thus, the flash flooding threat is greatest in
the late afternoon and evening while the storms are still
organizing and therefore have more chaotic and slow forward
motions.

Wegman



Day 2
Valid 12Z Mon May 11 2026 - 12Z Tue May 12 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR THE CENTRAL
GULF COAST...

...18Z Update...

A Marginal Risk of excessive rainfall was introduced for the
central Gulf Coast with this update. A strong cold front pushing
south out of the interior U.S. will interact with still sufficient
Gulf moisture (PWATs between 1.5 and 1.75 inches) along the coast
to force a renewed round of convection ahead of the front, which
may also interact with the sea breeze. Corfidi vectors suggest
storm movement will be fast towards the east, so backbuilding
potential appears low. However, this area was hard-hit with heavy
rain totaling over 3 inches in several areas of southeast
Louisiana, with totals up to 2 inches across much of the rest of
the Marginal Risk area just yesterday. Thus, while the area will be
recovering today through tomorrow morning, expect that any heavy
rainfall of meaningful duration may still lead to an instance of
flash flooding or 2, especially in the urban areas within the
Marginal Risk.

Wegman

Day 3
Valid 12Z Tue May 12 2026 - 12Z Wed May 13 2026

The probability of rainfall exceeding flash flood guidance is less
than five percent.

Wegman

Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Day 3 threat area: www.wpc.ncep.noaa.gov/qpf/99epoints.txt