FOUS30 KWBC 020806
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
406 AM EDT Thu Apr 2 2026

Day 1
Valid 12Z Thu Apr 02 2026 - 12Z Fri Apr 03 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
NORTHERN ILLINOIS, WISCONSIN AND MICHIGAN...

The primary area of interest for flash flooding will likely lie
over far northern Chicago suburbs up into the Milwaukee metro due
to the areal urban footprint and suggestion of heavier rainfall in
the area, especially the second round of convection. Fortunately,
rates are generally capped at 1-1.25"/hr at peak intensity with
much of the CAMs hourly outputs closer to 0.5-1"/hr for the
heaviest periods of impact. This lies right on the edge of any FFG
exceedance, so the threat will be somewhat capped overall for a
multitude of reasons. There will likely be two main rounds- the
first in the morning hours followed by a most robust line during
the afternoon when there will be more ample large scale
forcing/instability as the surface cold front approaches from the
West. Overall areal averages across the region will be in the 1-2
inch range with locally isolated higher amounts possible.

Campbell/Kleebauer


Day 2
Valid 12Z Fri Apr 03 2026 - 12Z Sat Apr 04 2026

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF
THE SOUTHERN PLAINS INTO THE OZARKS REGION...

Strong to severe thunderstorms along with embedded heavy rainfall
will track across the Southern/Central Plains into the Mississippi Valley/Midwest during this period. Moisture (with PWs over the
90th, perhaps 95th percentile) and instability are likely to pool
along and ahead of the associated cold front and produce widespread
convection. Storms likely beginning in the afternoon are expected
to get reinforced through the evening and night hours as a low
level jet picks up ahead of the cold front. Given that some of this
region has been drier, it will take awhile before there are
substantial flash flood concerns. Some of the highest amounts/rates
are likely to focus over parts of central and eastern Oklahoma
down into the Red River Basin between the Texas and Oklahoma
border. Consensus has areal averages of 1 to 3 inches while some of
the hi-res guidance is hinting at isolated maximums of 4 to 7
inches. Slight Risk area spans from north-central Texas to
southwest-southern Missouri.

Campbell/Kleebauer


Day 3
Valid 12Z Sat Apr 04 2026 - 12Z Sun Apr 05 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE CENTRAL
AND EASTERN GREAT LAKES SOUTHWESTWARD TO CENTRAL TEXAS AND THE
LOWER MISSISSIPPI RIVER VALLEY...

Much of the convection that evolves across the Marginal Risk area
on D3/Sat will depend on specific evolution of convective complexes
that originate from the central/southern Plains on D2/Fri. Although
those details are a bit uncertain at the time frame, general
consensus is that one or two MCSs will traverse the Mississippi Valley/Mid-South early in the forecast period before convective
redevelopment occurs upstream along a composite outflow/cold front
during peak heating hours from central Texas to Mississippi. Areas
of training are likely if this pattern holds, with initiating
boundaries supporting deep convection eventually becoming more
parallel to steering flow aloft. Portions of this region may
require an upgrade to Slight in later outlook updates.

Farther north, convective coverage is far less certain -
particularly from Illinois to Ohio. Deeper convection south of
these areas could disrupt inflow/instability and lead to a minimum
in precipitation in these areas. Again - this regime is uncertain.

The primary reason Marginal was maintained for D3 from Illinois
eastward to New York State and West Virginia was soils/local
sensitivity. Soils are wetter with eastern extent from prior
rainfall and could still be sensitive to even moderate rainfall by
D3/Sat in a few spots.

Cook
$$
--- MultiMail/DOS
* Origin: Project Scorpio TEST (618:250/6)

FOUS30 KWBC 030803
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
403 AM EDT Fri Apr 3 2026

Day 1
Valid 12Z Fri Apr 03 2026 - 12Z Sat Apr 04 2026

...THERE IS SLIGHT RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF
THE SOUTHERN PLAINS INTO THE OZARKS, MISSOURI VALLEY, AND UPPER
MISSISSIPPI VALLEY...

At the mid-levels, a stout wave over the Intermountain West
(centered over Wyoming) will migrate eastward throughout the day,
spreading increasingly strong mid-level flow and height falls from
the High Plains eastward toward the Mid/Upper Mississippi Valley.
At the surface, strong 850mb flow and poleward flux of
moisture/instability will become established along and ahead of a
low initially across the Kansas/Nebraska border region at the
beginning of the forecast period and persist through 12Z Sat. Late
in the forecast period, a cold front will migrate southward across
the southern Plains. Areas of scattered thunderstorms are expected
along and ahead the front and low especially during the afternoon
and evening, with several areas of flash flooding expected.

The primary area for flash flood potential will exist along the
OK/TX Red River vicinity southward toward central Texas and the Big
Country. Scattered thunderstorms are expected to develop during
the afternoon and evening across the region, with CAMs suggestive
of training/repeating behavior and local areas of 2-5 inch totals.
The glancing influence of the aforementioned mid-level wave across
the region lends some doubt on degree and location of
daytime/afternoon convective coverage, which should modulate the
flash flood risk substantially.

Even if convection materializes as depicted by CAMs, antecedent
dryness of ground conditions are a mitigating factor for a more
widespread or significant flash flood risk. Persistent training
will likely be needed for ground conditions to lose receptiveness
to rainfall on a widespread basis. Both pre-frontal convection and
convection moving in along a surface cold front late represent two
distinct regimes for heavy rain and flash flood potential - with
that risk eventually spreading toward I-35 in Texas and the DFW
Metroplex area through early Saturday.

Farther north, convection along the front will likely sweep through
portions of Missouri and Oklahoma, with a greater risk/potential
for multiple mergers and/or convective clusters with southward
extent. Areas just southeast of Kansas City received copious
amounts of rain Thursday and will probably not have fully recovered
before the incoming thunderstorm threat through early Saturday,
necessitating maintenance of Slight Risk probabilities there.

Lastly, models (primarily CAMs) depict potential for
repeating/training convection across portions of northeastern Iowa
and vicinity through much of the day (from 16-18Z through well into
the evening) along/near a surface warm front and well ahead of an eastward-moving cold front that should reach the area late in the
forecast period. NASA Sport soil moistures suggests slightly more
moist ground conditions in these areas, and the advance of the
mid-level wave and confluence on the northern end of strong 850mb
flow all point to prolonged deep convective potential. 3-5 inch
totals cannot be ruled out in this regime. A Slight Risk has been
added to the outlook in these areas as a result.

Though less widespread, additional convection should traverse wet
ground conditions across portions of Ohio, Pennsylvania, and
southern New York State, supporting continued Marginal
probabilities in that area.

Cook


Day 2
Valid 12Z Sat Apr 04 2026 - 12Z Sun Apr 05 2026

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FROM THE CENTRAL
AND EASTERN GREAT LAKES SOUTHWESTWARD TO CENTRAL TEXAS AND THE
LOWER MISSISSIPPI RIVER VALLEY...

Much of convective evolution during the D2/Sat forecast period will
depend on convective details from lingering convection across
Arkansas and Texas left over from D1/Fri. East-northeastward
progression of a mid-level wave toward the Great Lakes will aid in southeastward movement of a cold front from the Plains through the Ozarks/Mid-Mississippi Valley during the forecast period. This
front will gradually become more parallel to weakening flow aloft
from Texas to Mississippi, supporting additional opportunities for
training convection as storms organize along remnant outflows and
backbuild. This regime suggests that pockets of 1-3 inch rainfall
totals are likely especially from central Texas to northern
Alabama, with heavier totals also possible from central Mississippi
south into southeastern Louisiana as well. While Slight Risk
potential exists with this setup, concerns about 1) uncertainty of
prior-day convective evolution and 2) antecedent dryness continue
to be limiting factors for a more widespread flash flood risk at this time.

Farther north, convection is likely to be progressive across much
of the Lower Ohio Valley along with potential for inhibited
destabilization due to more widespread convection across the Lower
Mississippi Valley. Too much uncertainty exists to reduce the
Marginal Risk area at this time. Notable exceptions to this general
regime exist, however, from northern Ohio into southern New York
State and Pennsylvania, where models suggest appreciable daytime
heating and moderate instability developing. Storms may not be all
that fast moving either in Pennsylvania as that region should
reside on the southern extent of stronger mid-level flow into
southeastern Canada. Convective coverage is a bit uncertain, but
any greater-than-anticipated coverage of convection in this
environment could locally raise flash flood concerns - especially
with low FFGs noted across that area.

Cook


Day 3
Valid 12Z Sun Apr 05 2026 - 12Z Mon Apr 06 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
SOUTH TEXAS ON SUNDAY...

Maintained the Marginal Risk of Excessive rainfall area that was
introduced by the WPC Medium Range desk as a west-to-east oriented
front makes its way southward. Deeper moisture should e pooling
along and south of the boundary with precipitable water values
around 1.75 inches in place at the start of the outlook period.

Given uncertainties detailed n the Day 2 period with respect to the
timing and placement...combined with the 03/00Z NCEP global models
now showing the front to be more progressive than in earlier runs
which led to CAPE being swept out of South Texas faster...was not
inclined to introduce a Slight Risk area at this point. At the same point...spaghetti plots from the non-CAM ensembles still show
enough members with 1 inch QPF and a few contours of 2 inch QPF to
support keeping the Marginal area with only minor nudges around the periphery.

Bann
$$
--- MultiMail/DOS
* Origin: Project Scorpio TEST (618:250/6)

FOUS30 KWBC 030803
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
403 AM EDT Fri Apr 3 2026

Day 1
Valid 12Z Fri Apr 03 2026 - 12Z Sat Apr 04 2026

...THERE IS SLIGHT RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF
THE SOUTHERN PLAINS INTO THE OZARKS, MISSOURI VALLEY, AND UPPER
MISSISSIPPI VALLEY...

At the mid-levels, a stout wave over the Intermountain West
(centered over Wyoming) will migrate eastward throughout the day,
spreading increasingly strong mid-level flow and height falls from
the High Plains eastward toward the Mid/Upper Mississippi Valley.
At the surface, strong 850mb flow and poleward flux of
moisture/instability will become established along and ahead of a
low initially across the Kansas/Nebraska border region at the
beginning of the forecast period and persist through 12Z Sat. Late
in the forecast period, a cold front will migrate southward across
the southern Plains. Areas of scattered thunderstorms are expected
along and ahead the front and low especially during the afternoon
and evening, with several areas of flash flooding expected.

The primary area for flash flood potential will exist along the
OK/TX Red River vicinity southward toward central Texas and the Big
Country. Scattered thunderstorms are expected to develop during
the afternoon and evening across the region, with CAMs suggestive
of training/repeating behavior and local areas of 2-5 inch totals.
The glancing influence of the aforementioned mid-level wave across
the region lends some doubt on degree and location of
daytime/afternoon convective coverage, which should modulate the
flash flood risk substantially.

Even if convection materializes as depicted by CAMs, antecedent
dryness of ground conditions are a mitigating factor for a more
widespread or significant flash flood risk. Persistent training
will likely be needed for ground conditions to lose receptiveness
to rainfall on a widespread basis. Both pre-frontal convection and
convection moving in along a surface cold front late represent two
distinct regimes for heavy rain and flash flood potential - with
that risk eventually spreading toward I-35 in Texas and the DFW
Metroplex area through early Saturday.

Farther north, convection along the front will likely sweep through
portions of Missouri and Oklahoma, with a greater risk/potential
for multiple mergers and/or convective clusters with southward
extent. Areas just southeast of Kansas City received copious
amounts of rain Thursday and will probably not have fully recovered
before the incoming thunderstorm threat through early Saturday,
necessitating maintenance of Slight Risk probabilities there.

Lastly, models (primarily CAMs) depict potential for
repeating/training convection across portions of northeastern Iowa
and vicinity through much of the day (from 16-18Z through well into
the evening) along/near a surface warm front and well ahead of an eastward-moving cold front that should reach the area late in the
forecast period. NASA Sport soil moistures suggests slightly more
moist ground conditions in these areas, and the advance of the
mid-level wave and confluence on the northern end of strong 850mb
flow all point to prolonged deep convective potential. 3-5 inch
totals cannot be ruled out in this regime. A Slight Risk has been
added to the outlook in these areas as a result.

Though less widespread, additional convection should traverse wet
ground conditions across portions of Ohio, Pennsylvania, and
southern New York State, supporting continued Marginal
probabilities in that area.

Cook


Day 2
Valid 12Z Sat Apr 04 2026 - 12Z Sun Apr 05 2026

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FROM THE CENTRAL
AND EASTERN GREAT LAKES SOUTHWESTWARD TO CENTRAL TEXAS AND THE
LOWER MISSISSIPPI RIVER VALLEY...

Much of convective evolution during the D2/Sat forecast period will
depend on convective details from lingering convection across
Arkansas and Texas left over from D1/Fri. East-northeastward
progression of a mid-level wave toward the Great Lakes will aid in southeastward movement of a cold front from the Plains through the Ozarks/Mid-Mississippi Valley during the forecast period. This
front will gradually become more parallel to weakening flow aloft
from Texas to Mississippi, supporting additional opportunities for
training convection as storms organize along remnant outflows and
backbuild. This regime suggests that pockets of 1-3 inch rainfall
totals are likely especially from central Texas to northern
Alabama, with heavier totals also possible from central Mississippi
south into southeastern Louisiana as well. While Slight Risk
potential exists with this setup, concerns about 1) uncertainty of
prior-day convective evolution and 2) antecedent dryness continue
to be limiting factors for a more widespread flash flood risk at this time.

Farther north, convection is likely to be progressive across much
of the Lower Ohio Valley along with potential for inhibited
destabilization due to more widespread convection across the Lower
Mississippi Valley. Too much uncertainty exists to reduce the
Marginal Risk area at this time. Notable exceptions to this general
regime exist, however, from northern Ohio into southern New York
State and Pennsylvania, where models suggest appreciable daytime
heating and moderate instability developing. Storms may not be all
that fast moving either in Pennsylvania as that region should
reside on the southern extent of stronger mid-level flow into
southeastern Canada. Convective coverage is a bit uncertain, but
any greater-than-anticipated coverage of convection in this
environment could locally raise flash flood concerns - especially
with low FFGs noted across that area.

Cook


Day 3
Valid 12Z Sun Apr 05 2026 - 12Z Mon Apr 06 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
SOUTH TEXAS ON SUNDAY...

Maintained the Marginal Risk of Excessive rainfall area that was
introduced by the WPC Medium Range desk as a west-to-east oriented
front makes its way southward. Deeper moisture should e pooling
along and south of the boundary with precipitable water values
around 1.75 inches in place at the start of the outlook period.

Given uncertainties detailed n the Day 2 period with respect to the
timing and placement...combined with the 03/00Z NCEP global models
now showing the front to be more progressive than in earlier runs
which led to CAPE being swept out of South Texas faster...was not
inclined to introduce a Slight Risk area at this point. At the same point...spaghetti plots from the non-CAM ensembles still show
enough members with 1 inch QPF and a few contours of 2 inch QPF to
support keeping the Marginal area with only minor nudges around the periphery.

Bann
$$
--- MultiMail/DOS
* Origin: Project Scorpio TEST (618:250/6)

FOUS30 KWBC 060817
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
417 AM EDT Mon Apr 6 2026

Day 1
Valid 12Z Mon Apr 06 2026 - 12Z Tue Apr 07 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF FLORIDA...

Maintained the Marginal Risk area introduced on Sunday across
portions of Florida as a trailing tail of a cold front advancing
offshore the East Coast will be slowly moving through central
portions of the state. The front will provide a focus for showers
and thunderstorms to fire up along within the moist tropical
airmass. The 00Z HREF and RRFS neighborhood probabilities showed
several hours during which the rainfall rates pulsate between
0.50"/hr to 3+"/hr mainly from this afternoon into the evening.
Consequently there were not changes made.

Bann


Day 2
Valid 12Z Tue Apr 07 2026 - 12Z Wed Apr 08 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE EAST COAST OF THE FLORIDA PENINSULA...

A cold front will be passing over Florida which allows for deep
moisture to pool across the southern two-thirds of the peninsula with precipitable water values reaching into the 1.5 to 1.8 inch range
and moisture flux convergence along the front acts to focus and
support convection. The concern about excessive rainfall arises
from the locally heavy rainfall rates from any convection that
develops within such an environment as well as the fact that the
front should be slowing its southward motion keeps the window of
opportunity open longer for enhanced rainfall totals.

Bann


Day 3
Valid 12Z Wed Apr 08 2026 - 12Z Thu Apr 09 2026

...THERE CONTINUES TO BE A MARGINAL RISK OF EXCESSIVE RAINFALL OVER
PARTS OF THE FLORIDA PENINSULA...

A front draped across the southern portion of the Florida
peninsula acting as a focus for thunderstorms capable of producing
locally heavy rainfall across parts of the Florida peninsula. Some
of the guidance has a mesoscale low over the eastern Gulf that
begins to move towards the peninsula and starts to lift the front
northward during the latter part of the period. The inference is
that low level flow will be strengthening...especially on the
eastern side of the peninsula...which may enhance rainfall
amounts compared with amounts on Tuesday. Given the lack of
agreement within the suite of numerical guidance on where...or
if...this occurs preludes more than a Marginal risk area.

Bann
$$
--- MultiMail/DOS
* Origin: Project Scorpio TEST (618:250/6)