FOUS30 KWBC 020058
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
858 PM EDT Fri May 1 2026

Day 1
Valid 01Z Sat May 02 2026 - 12Z Sat May 02 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ALONG THE
CENTRAL GULF COAST INTO THE SOUTHEASTERN U.S....

As drier and more stable conditions continue to spread from west-
to-east across the previously highlighted areas, the Slight Risk
and much of the Marginal Risk areas were removed. However, a
Marginal Risk area was maintained for a portion of the region --
extending from southeastern Louisiana to southwestern Georgia and
the Florida Panhandle.

A series shortwaves will continue to move through the base of a
broader-scale trough centered over the northern Gulf. As this
energy moves east, modest surface wave development is expected
along the slow-moving boundary positioned over the northern Gulf.
This low is forecast to move east along the northern Gulf Coast,
with the trailing portion of the front and the leading edge of
drier air dropping southeast. As the evening progresses, rain will
diminish from west-to-east from eastern Texas into the lower
Mississippi Valley. Latest mesoanalysis shows the greater
instability south of the surface front and mostly out over the
northern Gulf -- keeping rainfall rates over land in check.
However, some pockets of greater instability and heavier rainfall
rates are brushing southeastern Louisiana and the Florida
Panhandle. This is expected to remain the case through the evening,
with the better instability and greater potential for intense
rainfall rates confined mostly to the immediate coast. However,
while instability further inland will be limited, model soundings
show the column becoming more saturated as southerly flow
intensifies ahead of the wave. This deep saturation has the
potential to support highly-efficient rains, with heavy amounts
possible. The updated Marginal Risk area reflects where recent runs
of the HRRR and the 18Z HREF indicate the greatest threat for
localized amounts over 2 inches this evening into the overnight.

Pereira

Day 2
Valid 12Z Sat May 02 2026 - 12Z Sun May 03 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE SOUTHEAST U.S....

21Z update... The latest QPF trends supported a minor southward
nudge of the Marginal across the northern peninsula. The QPF
footprint will largely span from Apalachee Bay through north-
central/northeast Florida and across southeast Georgia.

Campbell

A progressive upper trough is expected to help focus and sustain
showers and thunderstorms across portions of the Southeast United
States on Saturday into the early morning hours of Sunday. More
importantly...the trough should result in any convection moving
with minimal risk of back-building or training. The setup promotes
a relatively favorable environment suitable for heavy rainfall
with the stronger cell cores capable of producing rainfall rates
between 1-2"/hr in a region where Flash Flood Guidance values
remain high. There was enough of a signal for the possibility of
some urban flooding to warrant keeping a previously-issued Marginal
Risk in place with minimal amount of changes needed.

Bann

Day 3
Valid 12Z Sun May 03 2026 - 12Z Mon May 04 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THEM SOUTHEAST FLORIDA PENINSULA ON SUNDAY...

21Z update... Latest guidance and WPC QPF focuses the highest
rainfall over portions of Palm Beach, Broward and Hendry Counties,
which supported the reshaping of the western boundary of the
Marginal Risk.

Campbell

A cold front associated with an area of low moving northeastward
off the eastern US seaboard will be draped across the central
portion of the Florida peninsula on Sunday...with the front
separating an airmass with precipitable water values at or
somewhat less than 0.5 inches in the panhandle and adjacent
portions of the peninsula to values in the 1.75 inch to 2.00 inch
over the southern half of the peninsula for much of Sunday and
Sunday evening. Mid- and upper-level shortwave energy embedded
within fast flow aloft will help focus and sustain thunderstorms
that could produce 1.5 to 2.5 inch per hour along and south of the
boundary. There remained enough of a signal for the potential of
some urban flooding across the larger urban areas so opted to keep
with the Marginal Risk area due to the high flash flood guidance.
Even if the QPF remains similar in future cycles...where/how much
rain falls in Days 1 and 2 will affect the flash flood guidance as
Day 3 makes its way towards becoming a Day 1 outlook.
Regardless...downpours and localized multiple-inch rainfall amounts
in the major cities is more likely to have flood- related problems
in either scenario.

Bann


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