Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
315 PM EST Mon Nov 2 2026
Day 1
Valid 16Z Mon Nov 02 2026 - 12Z Tue Nov 03 2026
...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR AREAS BETWEEN
MELBOURNE AND PORT ST. LUCIE, FLORIDA...
...Florida...
15Z Special: A targeted MDT risk has been added in coordination
with the Melbourne WFO due to significant rainfall and high-end
impacts occurring from a convergent band of heavy precipitation
over the east-central FL coast. Rainfall totals of 5-15" have
fallen in a narrow corridor between Melbourne down to just north of
Fort Pierce leading to widespread flash flooding in this zone,
especially just south of Melbourne proper. More on this setup will
be included in the official 16z update.
16Z Update: Significant rainfall continues across the east-central
FL coast this morning within a narrow convergent zone on the
eastern edge of a slow-moving MCV positioned over west-central FL,
near Tampa. The current radar/sat composite show a swath of
moderate to heavy rainfall over the central portion of the state
with a narrow band of intense rainfall between Melbourne down
towards Port St. Lucie. Mesoanalysis indicates weak shear centered
over the eastern side of the peninsula with a prevailing east-
southeast flow between the surface to 850mb, followed by a strong
veering of winds between 700-300mb as the height field is dictated
via a persistent trough located over the entire stretch of the
state. The combination of shear and enhanced low-level convergence
within the eastern periphery of the complex has allowed for a
narrow corridor of repeating heavy rainfall with anchoring
positioned right along the coast where the instability gradient
coincides with the better effective layer shear positioned just
south of the Space Coast. Recent trends in both the HRRR/RRFS have
been providing an uptick in the QPF distribution as the hourly
models have finally caught on to the localized setup that's caused
quite a bit of trouble near Melbourne this morning. Expectation is
for an additional 2-4" with locally as much as 8" plausible in
this corridor along the coast, leading to a special ERO update to
include a targeted MDT ~15z this morning. The threat over the
coastal areas will continue through the first half of the afternoon
before the setup starts to slowly breakdown and we see the threat
dwindle before dissipation after 23-00z when all guidance shows
the threat fizzling out.
For areas inland, the convergent axis is right beneath the general
MCV circulation providing a secondary maxima to the northwest of
Lake Okeechobee where MRMS indicates 4-8" of rainfall already
occurring in this zone, as well, leading to a flash flood warning
for areas that normally don't usually see flash flooding due to
very high FFG's. This just indicates the type of environment we are
contending with and will continue to contend with through at least
part of the afternoon. For more information on the setup and impact
potential across the FL Peninsula, please see MPD #1549 for the
latest.
Kleebauer
...Midwest/Plains...
16Z Update: Two primary changes with the latest D1 update include
an expansion of the SLGT risk further northeast to include more of
northwestern MO into southern IA, as well as an additional MRGL
risk across western KS up into southern NE with a narrow band of
enhanced convection near the advancing cold front and trailing
surface low ejecting out of the southeast CO Front Range. Models
have been consistently upping the potential across the Missouri
Valley into the East-Central Plains with the cold front
encountering a maturing warm sector environment as our surface low
moves off to the northeast and amplifies over the next 24 hours.
Latest HREF/REFS mean QPF now indicates a swath of 1.5-2" areal
averages from northeast OK up through southeast KS into northwest
MO and far southern IA, a signal consistent with approaching at
least the 3-hr FFG exceedance threshold as noted via the 12z data.
Deterministic results a bit more robust with a strong signal for
locally >2" (60-90%), and modest probs (25-50%) for at least 3" in
the latest hi-res ensemble suite, enough to warrant the SLGT risk
and expansion to cover areas within those elevated probabilities.
The rest of the area encompassed by the MRGL remain pretty
consistent for the current risk with only minor modifications
necessary over the Mid-Mississippi Valley.
Kleebauer
..Previous Discussion..
A highly-amplified and multi-stream upper trough is forecast to
move east of the Rockies into the Plains today, producing
widespread precipitation across the central U.S. A well-defined
shortwave within the base of the trough will move from the Four
Corners this morning, into the central and southern Plains by this
evening. The potential for heavy rain is expected to increase this
evening across portions of the southern and central Plains,
especially from eastern Oklahoma and Kansas into western Missouri
as a 40-50+ kt southwesterly low level jet develops ahead of the
wave, supporting strong moisture advection into a region of
increasing ascent. Showers and storms are expected to develop with
the potential for heavy rates increasing as PWs increase to ~1.75
inches and right-entrance region upper jet forcing supports large-
scale ascent. Hi-res guidance indicates that elevated storms can be
expected during the late afternoon across portions of eastern
Oklahoma into the lower Missouri Valley before a more robust line
of storms develops and advances east ahead of a sweeping cold
front. In addition to the potential for more than one round of
storms, a period of training convection may elevate the risk for
localized heavy amounts and flash flooding. A Slight Risk was added
where both the HREF and REFS show high neighborhood probabilities
for accumulations over 3 inches. Both also showed neighborhood
probabilities for amounts exceeding 3-hr FFGs increasing into the
20-30+ percent range across portions of the area during 0-6Z
Tuesday timeframe.
Farther to the north, a Marginal Risk covering portions of the
northern Plains and upper Midwest was maintained. Widespread
coverage of 1-2 inch amounts across parts of the Dakotas and
Minnesota is forecast. However, not expecting any widespread flash
flooding concerns as limited instability will keep rainfall rates
in check.
Pereira
Day 1 threat area:
www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
315 PM EST Mon Nov 2 2026
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 2 threat area:
www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
315 PM EST Mon Nov 2 2026
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 3 threat area:
www.wpc.ncep.noaa.gov/qpf/99epoints.txt
Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
315 PM EST Mon Nov 2 2026
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
Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
315 PM EST Mon Nov 2 2026
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
