Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
251 PM EST Tue Nov 3 2026

Day 1
Valid 01Z Tue Nov 03 2026 - 12Z Wed Nov 04 2026

...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF THE
LOWER MISSISSIPPI TO THE TENNESSEE VALLEYS AND OVER PARTS OF
SOUTHEAST FLORIDA...

...16Z Update...
Only a subtle expansion of the Slight Risk area was made over
Arkansas as line of pre-frontal showers and thunderstorms approach
from the west. Reference Mesoscale Precipitation Discussion 1552
covering the area. The rainfall rates are not overwhelming but the
risk of flooding results from the risk of cell training and repeat
convecton.

No changes needed to the Slight risk area along the urban corridor
of southeaast Florida.

Bann

Previous Excessive Rainfall Discussion...

...East Texas to the Mid Mississippi, Lower Ohio, and Tennessee
Valleys...

Convection that has developed along a well-defined cold front will
remain ongoing, producing areas of moderate to heavy rain and
possibly isolated runoff concerns early in the period from central
Missouri back into east Texas. Rainfall rates are likely to wane
through the late morning hours before storms re-intensify farther
east from southeastern Missouri to Louisiana during the afternoon.
Ample moisture (PWs 1.50-1.75+) focused along a 40-50+ kt low level
jet interacting with strong upper jet forcing ahead of an
amplified shortwave will contribute to organized storms capable of
producing heavy rates. While the forward motion of these storms may
limit the threat for widespread heavy amounts and flooding
concerns, the intense rates produced by these storms are expected
to raise the threat for at least isolated runoff concerns,
especially in poor drainage and urbanized areas. As these storms
continue east across the Mid South, several hi-res guidance members
show them converging with less-organzied storms lifting out of the
southeast along the western edge of a persistent ridge that
extends across the Southeast. These converging storms are expected
produce an axis of heavy amounts centered from northwestern Alabama
through Middle Tennessee into Kentucky. A Slight Risk was
maintained across portions of the lower Mississippi Valley and Mid
South into the Tennessee Valley where the REFS and HREF indicate
widespread amounts of 1-2 inches, with locally heavier amounts, are
likely.

...Southeast Florida...

While the mid-level shortwave that helped organize heavy amounts
across central and southern portions of the state is expected to
weaken and drift west farther into the Gulf, deeper moisture will
linger across southern Florida. Persistent easterly flow will
maintain PWs around 2 inches across portions of Southeast Florida,
supporting storms capable of producing efficient, heavy downpours.
While storms that develop are expected to be less organized and the
footprint of heavy rains more confined than yesterday, there is
the potential for additional localized heavy amounts that may
exacerbate ongoing flooding. A small Slight Risk was introduced
across Southeast Florida where the HREF and REFS indicate that
localized additional amounts of 3+ inches are likely today.

Pereira


Day 2
Valid 12Z Wed Nov 04 2026 - 12Z Thu Nov 05 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF SOUTHEAST FLORIDA AND FROM THE TENNESSEE VALLEY INTO THE LOWER
OHIO VALLEY AND SOUTHERN APPALACHIANS...

...Tennessee Valley to the Lower Ohio Valley and Southern
Appalachians...

On-going convection at the start of the period will continue to be
capable of producing sufficient rainfall rates to produce isolated
threat for runoff concerns into the early hours of the Day 2
period. Then by the afternoon, moist southerly flow into the
southern Appalachians along with modest mid-to-upper level forcing
will contribute to an increasing chance for locally heavy showers
and storms. The general consensus of the 12Z guidance indicates
that orographically focused amounts of 1-2 inches, with isolated
heavier amounts, can be expected across portions of the Tennessee
Valley as well as from northern Georgia into the southern Blue
Ridge.

...Southeast Florida...

The threat for heavy amounts and flooding concerns will continue to
diminish during the period. However, isolated heavy amounts with
flash flooding especially in the urbanized coastal areas can not be
entirely ruled out given some overlap with areas soaked since
Saturday. While drier air will continue to spread into the region,
especially late in the period, PWs remaining near 2 inches could
support some additional afternoon heavy downpours, resulting in
additional isolated runoff concerns.

Pereira/Bann


Day 3
Valid 12Z Thu Nov 05 2026 - 12Z Fri Nov 06 2026

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

Bann


Day 4 and Day 5

Valid 12Z Fri Nov 06 2026 - 12Z Sun Nov 08 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR SOUTHERN NEW
ENGLAND ON FRIDAY...

20z Update: Marginal risk was maintained from NYC into southern New
England. The model consensus supported a minor eastward shift to
the western extent of the Marginal, but otherwise a swath of 2-5"
still appears probable across the area. While the 12z models show
above average agreement on this axis, we are still 4 days out, and
thus additional fluctuations in the rainfall axis are likely. Still
in the realm of possibilities it shifts east and is mainly
offshore...but enough model support and run to run consistency to
maintain the Marginal, with the best chances of localized flash
flooding appearing to be from Long Island into eastern CT, RI and
eastern MA.

Chenard

...Previous Discussion...

A Marginal risk area was added for southern New England, NYC and
Long Island with this update. There remains considerable
uncertainty how fast the front over the Northeast sweeps east,
especially into the Mid-Atlantic. However, there is better
certainty about a corridor of heavier rain getting hung up across
southern New England on Friday. Soils all up and down the Eastern
Seaboard, with the notable exception of Florida, remain very dry
after over 2 weeks without a drop of rain. Thus nearly all of the
expected rainfall will be beneficial. However, the plume of
moisture with PWATs over 1.5 inches stalling over New England,
potential for some limited instability to support some convective
elements, upslope, and plentiful urban areas will all support the
possible development an isolated instance of flash flooding or two.
This will be where the heaviest rains are most persistent. Thus,
this is a low-end Marginal as considerable uncertainty remains.

On Saturday, lingering rain in eastern Maine, and a weak tropical
disturbance approaching the lower Texas coast both have the
potential to cause an isolated instance of flash flooding or two in
those respective areas. In Maine several pieces of guidance move
the heaviest rains east into New Brunswick and Nova Scotia faster.
Meanwhile in Texas, a lot of the expected rain may stay offshore
where there will be much more instability. These factors precluded
a Marginal Risk issuance for now in both areas.

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