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FOUS30 KWBC 080800
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Fri May 8 2026

Day 1
Valid 12Z Fri May 08 2026 - 12Z Sat May 09 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
SOUTHEASTERN LOUISIANA AND SOUTHERN MISSISSIPPI...

...Lower Mississippi Valley/Central Gulf Coast...
A robust moisture pool is expected to deepen along the central Gulf
Coast today as southwesterly winds amplify ahead of energy moving
out of eastern Texas and the northwestern Gulf. This flow will
support PWs climbing to around 2 inches along a slow-moving front,
or more than 2.5 std dev above normal. The majority of the CAMs
are in good agreement indicating a corridor of training convection
developing by the afternoon across southeastern Louisiana and
southern Mississippi. Given the high moisture content and potential
for training, localized totals of 2-3+ inches are possible. High
hourly rates within these training storms will pose a risk for
flash flooding, particularly in low-lying and urban areas, with
the highest potential impact centered along the I-10 corridor. The
introduced Slight Risk area reflects high neighborhood
probabilities shown by both the HREF and RRFS for amounts exceeding
2 inches.

...South Texas...
Farther west, a well-defined mid-to-upper level shortwave/low
moving through northern Mexico into West Texas will provide
increasing ascent. Moist southerly flow interacting with this
feature and upslope into the Sierra Madre Oriental will support
storms developing over northeastern Mexico. While much of this
activity may remain south of the international border, there are
some hi-res members that show some of these convective clusters
moving into South Texas. Though model spread is higher in this
region, both the HREF and RRFS indicate that localized totals
exceeding 2 inches are possible. Therefore, a Marginal Risk was
maintained to account for this potential.

Pereira

Day 2
Valid 12Z Sat May 09 2026 - 12Z Sun May 10 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE CENTRAL
GULF COAST INTO THE SOUTHEAST...

The previously noted shortwave moving into West Texas on Day 1 is
forecast to move eastward along the central Gulf Coast on Saturday.
While lingering deep moisture will remain in place, the synoptic
signal for organized and widespread heavy rainfall becomes
significantly more diffuse. Current model guidance lacks a
concentrated signal for high-end totals, suggesting a more isolated
or low-end flash flood threat. Given the environment and the
potential for antecedent conditions driven the previous day`s heavy
rains, the current Marginal Risk was maintained for this cycle. But
should model trends continue to show a lack of organization, this
area may be discontinued in future updates.

Pereira

Day 3
Valid 12Z Sun May 10 2026 - 12Z Mon May 11 2026

...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL ACROSS PORTIONS
OF NORTHEASTERN TEXAS, SOUTHEASTERN OKLAHOMA, SOUTHERN ARKANSAS,
AND NORTHERN LOUISIANA...

Shortwave energy diving into the base of broader scale trough will
drive a cold front southward across the region. Southerly flow
ahead of the boundary will boost PWs to over 1.5 inches. This
moisture, combined with favorable upper jet forcing, will support
storms developing along and ahead of the front. While model spread
is currently too high to support a higher risk area and the signal
for widespread heavy totals remains muted, locally intense rates
along with some areas of repeating cells could result in isolated
flash flooding.

Pereira

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