Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
802 PM EST Mon Nov 2 2026

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

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
CENTRAL AND SOUTHERN FLORIDA...

...Florida...
We will maintain a Slight risk across much of central and southern
FL, with the main focus continuing to be along the east coast of
the state. Overall coverage and magnitude of heavy rainfall should
generally be lower overnight than what we have been seeing, with
overall synoptic forcing and high res model QPF on a downward
trend. However, low level easterly flow will continue, and recent
HRRR forecasts show a continuous influx of instability into the
state through the overnight hours. So while convective coverage may
decrease, the potential for localized extreme rainfall will
continue given the instability, PWs and coastal convergence
persisting. Overall it seems like the threat is greatest south of
the areas hardest hit over the past 48 hours, but overall
confidence on the details remains low. Model guidance has not been
doing a great job with the mesoscale details, and thus
observational trends will need to be relied upon for the overnight
convective evolution.

...Plains...
Localized flash flooding will be possible overnight from portions
of TX into IA. Through the evening hours the risk may be maximized
along a strong low level convergence axis from western KS into
southern NE. Instability should erode fairly quickly here, and thus
the risk should peak within the next couple hours. Thereafter the
strongest convection should be from TX into MO. While some initial
training is possible, the overall storm mode should be a
progressive convective line. This should keep the flash flood
threat isolated in nature and mainly confined to a rate driven
urban risk, and thus we were able to remove the Slight risk with
this update.

Chenard


Day 2
Valid 12Z Tue Nov 03 2026 - 12Z Wed Nov 04 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL PORTIONS OF MID-
SOUTH...

...Lower and Mid-Mississippi Valley...

20Z Update: Only small modifications were necessary for the
inherited SLGT risk across the Lower Mississippi Valley with the
emphasis of flash flooding still within the zone between northern
MS, southwestern TN, over into far northwest AL. The trend from
guidance was to press the front a bit faster to the east leading to
heavier precip axis located a bit downstream of where the previous
QPF max was located. ML guidance is still highlighting the area
back near the Mississippi with the max over the Mississippi Delta
into southwestern TN. Secondary max showing up within the CAMs over
southern AR, back towards the ArklaTex where the instability is the
greatest and low-level convergence will be maximized in the
afternoon hours during the maturing instability period. FFGs
further southwest are running very high due to a prolonged drought
in the region, so refrained from a SLGT risk expansion into this
particular zone, but smaller towns across southern AR back towards
Shreveport may see local flash flood prospects a bit higher
compared to surrounding areas. FFG exceedance probs are still
focused up near Memphis and northern MS into western TN with a
potential for heavy rainfall back up to the west of Nashville. The
SLGT risk was expanded a bit north of the previous issuance and bit
east to account for the faster trend of the cold front advancement
which correlates to heavier rainfall potential downstream.

Kleebauer

..Previous Discussion..

The general consensus of the hi-res guidance shows that storms
developing late Monday will remain ongoing along an advancing cold
front extending from the mid Mississippi Valley back into eastern
Texas Tuesday morning. There is some indication in the guidance
that heavy rates and continued southwest-northeast training may
elevate the threat for heavy amounts and flash flooding from the
Ozark region into southeastern Missouri. This suggests an upgrade
may need to be considered at some point, but for now maintained the
outlook at just a Marginal Risk. Farther east, a Slight Risk
centered over the Mid-South was maintained -- where deep moisture
and favorable upper jet forcing are expected to support
re-intensifying storms capable of producing heavy rainfall rates.
The previous Slight Risk was largely maintained, but adjusted a
little to reflect the REFS high neighborhood probabilities for
2-3+ inches across this area.

Pereira

...Florida...

20Z Update: Mo changes to the previous forecast as the forecast
remains on track from the last forecast issuance. The heavy totals
the previous 24hrs will only add to the threat over the east-
central FL coast as soil moisture will maintain well above normal
state with the latest soil moisture percentiles already pushing
above 90% for areas between Melbourne to Port St. Lucie/Stuart
area. This will provide an enhanced prospect for flash flooding,
even if the setup isn't as pronounced as previous periods. Heaviest
rainfall within the latest 12z HREF/REFS means are a bit south
compared to today's activity, so this may help limit future impacts
as the best convective risk lies away from the hardest hit
location. No matter the case, there is still at least an isolated
threat for flash flooding with the prevailing easterly flow over
the peninsula for Tuesday.

Kleebauer

..Previous Discussion..

Easterly flow will weaken this period; however, with anomalous
moisture remaining in place, cannot rule out additional localized
heavy rainfall amounts resulting in at least isolated flash
flooding concerns, especially in urbanized locations and areas
previously inundated with heavy rains.

Pereira


Day 3
Valid 12Z Wed Nov 04 2026 - 12Z Thu Nov 05 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE
TENNESSEE AND LOWER OH VALLEYS TO THE SOUTHERN AND CENTRAL
APPALACHIANS...

20Z Update: Only minor changes to the previous MRGL risk with the
main area of interest still aligned within the upslope area across
the Southern Appalachians. A bit of an expansion of the MRGL risk
over southern Ohio, as well, with some of the trends showing
greater convective potential over the Central Appalachian area
ahead of the cold front. Considering the more sensitive nature of
the terrain in this area of the CONUS, opted to expand the risk to
cover for the low-end threat. Totals generally 1-2" in the most
impacted areas, but global ensembles indicate some risk of 2-3" in
isolated areas which could very much cause some flash flood
concerns in the region of interest. Will assess in the coming days
with the additional forecasts from the CAMs, but antecedent dryness
will likely curb any widespread flash flood threat, unless
magnitudes increase in the coming days.

Kleebauer

..Previous Discussion..

Activity developing late Tuesday may continue into the early part
of the period, with a ribbon of deep moisture and favorable upper
jet forcing contributing to additional heavy rates and possible
flash flooding across parts of the Tennessee and lower Ohio valley
early on. Storms are forecast to shift east into the central and
southern Appalachians later in the day, where orographic effects
may help bolster totals across parts of the region and raise flash
flooding concerns, especially in the more sensitive parts of the
central Appalachians.

Pereira


Day 4 and Day 5

Valid 12Z Thu Nov 05 2026 - 12Z Sat Nov 07 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Enough model spread remains to withhold adding any Marginal risk
to the Mid-Atlantic and Northeast. Still looks like the front will
stall near the coast and allow for an axis of heavier rainfall
amounts. A solution such as the 12z ECMWF would probably result in
at least a localized flash flood risk from the eastern Mid-
Atlantic into southern New England, with 2-3" of rain and ~500 J/kg
of CAPE allowing for some embedded higher rainfall rates. However,
other models are further east with this axis (mainly offshore),
and the degree of instability is also uncertain. Given the dry
antecedent conditions we will hold off on adding a risk area until
we have more confidence in an onshore rainfall axis and some
overlapping instability.

Chenard


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