Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
411 AM EDT Thu Jul 3 2025

Day 1
Valid 12Z Thu Jul 03 2025 - 12Z Fri Jul 04 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS WESTERN
PORTIONS OF THE FLORIDA PENINSULA, WEST TEXAS, AND NEW MEXICO...

...Southwest to the Southern Plains...
A mid-to-upper level shortwave moving into southern California
this morning will move into the Four Corners region by this evening
and then the central and southern Rockies overnight. The large
scale lift associated with the wave, along with ample moisture
remaining in place, are expected to produce widespread showers and
thunderstorms across Arizona and New Mexico. A Slight Risk was
maintained across the eastern New Mexico and West Texas mountains
into the High Plains, where additional storms are expected to
develop across the same areas that have received several rounds of
storms and periods of flash flooding over the past several days. A
Marginal Risk was maintained farther to the north into the central
Rockies, extending into parts of southern Wyoming, where the
overnight guidance continues to indicate the potential for
localized heavy amounts as the deeper moisture is drawn northward
ahead of the advancing shortwave.

While differing in the details, the models continue to show a
notable signal for more widespread heavy amounts developing further
east into parts of central Texas. Continued to extend the Slight
Risk from eastern New Mexico and West Texas out into parts of
Northwest Texas and the Hill Country. Persistent southerly flow
will support a widespread area of PWs AOA 2 inches (+3 std dev),
supporting the potential for heavy amounts. The Slight Risk was
drawn to include areas where the 00Z HREF showed high neighborhood
probabilities for amounts of over 2 inches, with notable
probabilities for amounts of 3 inches as well.

...Eastern Oklahoma to central Louisiana...
A slow-moving returning boundary is expected to become the focus
for deeper moisture (PWs ~2 inches), which along with daytime
heating and modest mid-to-upper level forcing, is expected to
produce a swath of slow-moving storms later today, capable of
producing heavy rainfall rates and accumulations. The overnight
HREF shows a decent signal for some locally heavy amounts,
especially from central/southeastern Oklahoma through the ArkLaTex
into central Louisiana. Neighborhood probabilities for amounts
over 2 inches are above 50 percent across this region. Given the
relatively high FFGs covering much of this area, opted to introduce
just a Marginal Risk area at this time.

...Southeast...
Not much change from the previous outlook, with heavy rain
associated with a slow-moving wave developing along the trailing
end of a front settling along the Gulf Coast. Supported by onshore
flow ahead of the wave as it develops neat the Florida Big Bend
and drops south, the heaviest amounts are still expected to focus
along the Sun Coast. HREF neighborhood probabilities for amounts
above 3 inches are well above 50 percent across this region.
Therefore, the Slight Risk was maintained. Guidance continues to
show a sharp gradient further inland. Therefore, just a Marginal
Risk was maintained across much of the remaining peninsula and
further north along the Southeast Coast.

...North Dakota/Northwest Minnesota...
Storms are expected to develop later this evening across North
Dakota along a slow-moving warm front and ahead of a subtle
shortwave moving into the High Plains. Southerly flow is expected
to support an uptick in PWs (~1.5 inches). While widespread heavy
amounts are not expected, models do show some potential for locally
heavy amounts, bolstered by a period of slow-movement followed by
training cells. A Marginal Risk was introduced for the area where
the HREF showed high neighborhood probabilities for amounts over an
inch. The HREF indicates the greater threat for heavier amounts
centers over northwestern North Dakota, where slow-moving storms at
the onset may produce locally heavy amounts. The HREF shows some
modest probabilities for amounts over 2 inches across this area.

...Wisconsin...
A Marginal Risk was also added over portions of Wisconsin, where a
downstream portion of the previously noted front will become a
focus for deeper moisture and slow-moving storms tonight. The
signal for heavy amounts and potential flash flooding is a little
greater across this area. Amplifying southwesterly low level inflow
will support PWs climbing to ~1.5-1.75 inches, which along with a
weak shortwave moving across the top of an upper ridge, will
support storm development. Guidance indicates slow storm movement,
with some backbuilding, supporting the potential for locally heavy
amounts. The HREF shows neighborhood probabilities as high as 50
percent for amounts over 2 inches centered over northwestern
Wisconsin.

Pereira

Day 2
Valid 12Z Fri Jul 04 2025 - 12Z Sat Jul 05 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
EASTERN NORTH DAKOTA AND NORTHWESTERN MINNESOTA...

...Northern/Central Plains and Upper Midwest...
A much stronger signal for heavy amounts and possible flash
flooding is expected to unfold across parts of eastern North Dakota
and northwestern Minnesota late Friday into early Saturday.
Southerly winds ahead of a shortwave trough lifting northeast into
the Northern Plains will support PWs climbing to ~2 inches (+2 to
3 std dev). Storms are expected to develop by late afternoon and
train southwest to northeast ahead of a slowly advancing cold
front. With the HREF indicating that 12-hr amounts (ending 00Z Sat)
are likely to exceed 2 inches in some locations, a Slight Risk was
introduced across parts of eastern North Dakota and northwestern
Minnesota. A Marginal Risk was maintained farther to the south into
parts of the Central Plains where convection developing over the
High Plains during the afternoon is expected to advance more
steadily east, limiting the heavy rainfall/flooding threat.

...Southern Plains...
While the better forcing is expected to lift to the north, plenty
of moisture will remain (PWs ~2 inches), fueling the potential for
additional storms and heavy amounts. A Marginal Risk was introduced
across portions of Northwest Texas into Southwest Oklahoma -
centered where some the guidance shows at least locally heavy
amounts.

...Northern Rockies...
A Marginal Risk was maintained across parts of Idaho, western
Montana, and northwestern Wyoming, where widespread light to
moderate, with embedded locally heavy amounts are expected. A well-
defined shortwave trough along with fairly anomalous PWs (+1 to 2
std dev) are expected to support locally heavy amounts and an
isolated flash flooding threat.

...Florida...
The environment will remain favorable for widespread rain and at
least locally heavy amounts across much of the peninsula, with some
areas possibly seeing additional amounts over 3 inches. While an
upgrade to a Slight Risk may be forthcoming, model spread remains
fairly significant, and therefore maintained just a Marginal Risk
for now.

Pereira

Day 3
Valid 12Z Sat Jul 05 2025 - 12Z Sun Jul 06 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE UPPER MIDWEST AND THE SOUTHEAST...

...Upper Midwest...
Heavy rain developing Day 2 will continue well into Saturday as the
previously noted shortwave and preceding axis of deep moisture
advance from the Northern Plains into the upper Great Lakes. Model
show PWs at or above 2 inches extending as far north as the
Minnesota Arrowhead and the Michigan U.P. With some signal for
training storms to continue, an upgrade to a Slight across some
parts of the region may be forthcoming if the signal persists and
the models start to show greater agreement.

...Southeast...
With the aforementioned wave expected to move out along the
Southeast Coast, a Marginal Risk was maintained from coastal
Georgia to southeastern North Carolina, where the threat for heavy
rains is expected to increase. A Magical Risk was also maintained
along the west coast of Florida along the trailing inflow and axis
of high PWs.

Pereira

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