Weather Prediction Center

National Oceanic and Atmospheric Administration

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
350 AM EDT Sat Jul 19 2025

Valid 12Z Sat Jul 19 2025 - 12Z Mon Jul 21 2025

...Expansive Excessive Rainfall threat to encompass much of the Midwest,
Ohio Valley, and Mid-Atlantic with locally significant areas of flash
flooding possible...

...Severe weather likely over parts of the Northern/Central Plains,
Midwest, Mid-Atlantic, and Northeast this weekend...

...Dangerous summer heat wave to grow across the Central Plains,
Mississippi Valley, and Southeast into next week...

This weekend's weather pattern has a "Ring of Fire" look over the eastern
two-thirds of the Lower 48. A ridge of high pressure atop the southeastern
U.S. will keep the South mired in sultry conditions while an active jet
stream is situated over the northern periphery of the Southeast ridge.
Over the Southern Plains, a steadfast low-level jet will direct rich
tropical moisture northward towards a semi-stationary frontal boundary
oriented west-to-east from the Midwest to the Ohio Valley and
Mid-Atlantic. As Pacific disturbances embedded within the west-to-east
oriented jet stream race across the northern U.S., they will help to
enhance the strong-to-severe thunderstorms along and north of the
elongated frontal boundary. These storms will tap into the tropical
air-mass and pose a broad flash flood threat across a large section of the
east-central U.S.. WPC has a Slight Risk (threat level 2/4) in place from
eastern Nebraska all the way to the Mid-Atlantic coast today. The front
does not make much progress east on Sunday, keeping much of Corn Belt and
Ohio Valley under a Slight Risk for Excessive Rainfall once again. There
is the potential for training thunderstorms that could result in locally
significant flash flooding in parts of the Midwest and Ohio Valley this
weekend.

Flash flooding is not the only threat that portions of the Great Plains,
Midwest, and Mid-Atlantic face this weekend, as the same storms that pose
a flash flood threat could be severe in some cases. The Storm Prediction
Center (SPC) has issued three separate Slight Risks (threat level 2/5) for
portions of these regions. By Sunday, severe storms are still possible
from the Great Plains to the Northeast, but a strong cold front passing
through the Northeast will become a focus for organized severe storms. SPC
has a Slight Risk from the Poconos on east to the Maine coast with metro
areas such as NYC, Hartford, Providence, and Boston within the Slight Risk
area. Severe storms this weekend will be capable of producing damaging
wind gusts and large hail, with the potential for tornadoes as well. Look
for additional thunderstorms capable of producing flash floods and severe
weather to stick around in parts of the Northern Plains and Southeast to
kick-off the start of the upcoming work-week.

The aforementioned ridge of high pressure over the Southeast will lock in
place the kind of searing heat and oppressive humidity that occurs during
the "Dog Days of Summer" from the Southern Plains and Lower Mississippi
Valley to the Southeast. HeatRisk shows a growing footprint of Major
Impacts from the Ozarks and Ohio-Mississippi River Confluence to the
Southeast Coast. There are some localized cases of Extreme Impacts in
parts of southern Georgia and northern Florida. Heat Indices throughout
these regions will range between 105-110F with some instances where heat
indices reach 115F. Extreme Heat Warnings and Watches are out for portions
of the Central Plains and Middle Mississippi Valley that linger into the
first half of the upcoming work-week. There are also Heat Advisories for
parts of Oklahoma, Arkansas, and along the Southeast coast. The Southeast
ridge looks to become a more pronounced heat dome over the east-central
U.S. later next week. Please review our ongoing Key Messages for
additional details on next week's expanding heat wave.

Mullinax


Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
253 AM EDT Sat Jul 19 2025

Valid 12Z Tue Jul 22 2025 - 12Z Sat Jul 26 2025

...Major heat wave building from the Southeast into parts of the
Central U.S. next week and beyond...

...Overview...

The overall weather pattern next week will be dominated by a
building upper level ridge that will be situated over the Deep
South and extending north to the Tennessee and Ohio River valleys.
Heat and humidity build to dangerous levels across much of the
Central U.S. and extending to the Southeast and Deep South. An
active flow pattern will be in place to the north of this high as
multiple shortwave impulses track eastward over the northern tier
states and then New England. A cold front provides some relief
from the recent heat and humidity from the Mid-Atlantic to the
Northeast to start the week, followed by hotter weather mid-week
and beyond. Meanwhile, an upper level trough likely develops near
the West Coast going into early next week.


...Guidance/Predictability Assessment...

The 12Z model guidance suite has a good depiction of the general
weather pattern to start the forecast period Tuesday, and thus a
deterministic model blend works very well as a starting point. The
past few runs of the GFS are more robust with shortwave energy
crossing near the U.S./Canada border and limit the northward extent
of the main upper ridge more so than the overall model consensus
and the AIFS guidance, so its contribution to the preferred blend
was a little less than the CMC and ECMWF models. Elsewhere, there
remain some placement differences with the upper trough that
develops off the California coast late in the week, but it does not
currently appear to have a major effect on the overall forecast.
The ensemble means were gradually increased to about 50% by
Saturday.


...Weather/Hazards Highlights...

It remains the case that an axis of unsettled weather will remain
in place across the Upper Midwest and also the Southeast U.S. for
the beginning to middle of the week. Thunderstorm complexes
traveling around the northern periphery of the big upper high will
likely produce localized areas of heavy rainfall, potentially
exceeding an inch per hour or more. Therefore, a broad Marginal
Risk area extends from the eastern Dakotas to the western Great
Lakes on Tuesday where a cold front will be intersecting a warm and
humid airmass to the south. There is a good chance that a Slight
Risk could eventually be needed in later outlooks as confidence on
the main QPF axis becomes more certain. Across the Deep South and
northern Florida, a lingering stationary front will help focus deep
moisture with a potential wave of low pressure developing along it,
with some 1-3 inch rainfall totals possible for some areas.
Therefore, a Marginal Risk area is valid here for both Tuesday and
Wednesday.

Heat will once again make weather headlines for much of next week
across a large portion of the southern and central U.S. with a
large upper high becoming anchored over the Mid-South. Widespread
major impacts on the Heat Risk scale are expected from the Central
Plains to the Southeast states early in the week, and these higher
impacts then reach the Midwest and Ohio Valley by mid to late week.
This will be due to widespread highs in the lower 90s to low 100s
for many of these areas, in combination with dewpoints well into
the 70s, and overnight lows remaining uncomfortably warm. This will
likely have some staying power beyond this forecast period based
on the latest week two outlook from the Climate Prediction Center
from the Central Plains to the Gulf Coast region.

Elsewhere across the nation, there should be just enough monsoonal
moisture in place across eastern Arizona and much of New Mexico,
and probably extending into southern portions of Colorado, and
given the potential for some isolated slow moving storms, a
Marginal Risk is in place for both Tuesday and Wednesday. Across
the East Coast region, a cold front is forecast to clear the
Northeast and the Mid-Atlantic region through Tuesday, and
bringing a higher quality airmass after all of the heat and
oppressive humidity lately and lower rain chances. However, the
heat will likely return towards the end of the week as the Canadian
surface high moves offshore and a more southerly flow commences.

Hamrick


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw

Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
213 AM EDT Sat Jul 19 2025

Valid 00Z Sun 20 Jul 2025 - 00Z Sun 27 Jul 2025

The main subtropical surface high over the eastern Pacific will be
positioned well north of the Islands through this weekend and into
next week, generally between 40 and 45 degrees north. The state
will be on the far southern periphery of this high, and this will
keep a general easterly low level flow in place, with some backing
to the northeast at times through the next 7 days. The ensemble
means are in good synoptic scale agreement on the overall pattern.

In terms of rainfall prospects, there may be a slight increase in
showers across the Islands through Sunday night owing to a weak
upper level trough over the region, but otherwise the normal trade
wind induced showers can be expected through the remainder of the
week with no major rainfall events expected.


Hamrick

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
350 AM EDT Sat Jul 19 2025
Day 1
Valid 12Z Sat Jul 19 2025 - 12Z Sun Jul 20 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE MIDWEST, THE MID-SOUTH, THE SOUTHERN MID-ATLANTIC STATES, &
THE SOUTHERN APPALACHIANS...


Corn Belt/Ohio Valley/Mid-Atlantic States/Mid-South...
Ample moisture exists regionally. Some of this is due to the
synoptic pattern, with the Westerlies stronger than and south of
July norms which is allowing for greater effective bulk shear and
thunderstorm organization. Some of the moisture influx is also due
to the flow around the retrograding 3 sigma warm core ridge for
mid- July moving into the eastern Gulf. Additional moisture is
being imported from the direction of the former tropical
disturbance. Regardless of the source, precipitable water values
are forecast to crest at or above 2.25". ML CAPE could exceed 4000
J/kg due to daytime heating. Portions of IA, IL, and KY have the
potential for backbuilding convection both Saturday morning and
Saturday night/Sunday morning. Across IA, there is a question about
how much overlap convection dropping in from the north this
morning would have with convection Saturday night/Sunday morning.
Within such an environment, hourly rain amounts to 4" are possible,
with local amounts to 8". At the moment, these amounts are not
explicitly forecast by much of the guidance, with the 00z HREF/18z
RRFS showing minimal potential for 5"+ amounts, centered across IA.
However, the high resolution NAM and Canadian Regional show local
totals in the 6" ballpark. Large swaths of the region have had
well above average rainfall during the past week, saturating soils.
Since there's a bit of uncertainty, coordination with DMX/Des
Moines IA and DVN/Davenport IA have left the risk area as a high-
end Slight. However, should cells train for 2+ hours downstream of
existing instability pools, localized Moderate or High Risk
impacts cannot be ruled out.


Southwest/Southern Rockies...
Enough moisture is available for scattered monsoon convection again
on Saturday. Hourly amounts to 2" are possible due to diurnal
heating, which would be most problematic in urban areas, dry
washes/arroyos, or burn scars.


Roth


Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
350 AM EDT Sat Jul 19 2025
Day 2
Valid 12Z Sun Jul 20 2025 - 12Z Mon Jul 21 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
MIDWEST, SOUTHERN APPALACHIANS, & NORTHERN PLAINS...


...Midwest, Ohio Valley, & Southern Appalachians...
High moisture for Saturday persists into Sunday -- precipitable
water values eclipsing 2.25" -- with the core of the instability
pool more significant across portions of the Ohio Valley on Sunday
as warming at 700 hPa occurs across the Central Plains, slowly
strengthening a mid-level capping inversion. Effective bulk shear
should remain sufficient for convective organization. Inflow off
the instability pool could lead to backbuilding, so the potential
for 4" amounts in an hour and local 8" totals remains (the 00z NAM
advertised 7"). There's not enough confidence on where the higher
amounts will materialize to upgrade to a Moderate Risk, but a
higher end Slight Risk appears to exist from in and near southern
IL into KY, TN, southern WV, and westernmost VA. Localized Moderate
or High Risk impacts cannot be ruled out.


...Northern Plains...
Much of North Dakota will be at the nose of a potent low level jet
across the area. A subtle shortwave in the upper level jet may be
all it takes to initiate a line of storms across the region,
though there may be two separate rounds: one in the morning and a
second Sunday night. There is considerable uncertainty both with
storm intensity and receptivity of the ground to the heavy
rainfall. Used the recent guidance to trim some of the Slight Risk
area away. Like continuity, believe this is a lower end Slight
Risk.


Southwest/Southern Rockies...
Enough moisture is available for scattered monsoon convection on
Sunday. Hourly amounts to 2" are possible due to diurnal heating,
which would be most problematic in urban areas, dry washes/arroyos,
or burn scars.


Roth/Wegman


Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
350 AM EDT Sat Jul 19 2025
Day 3
Valid 12Z Mon Jul 21 2025 - 12Z Tue Jul 22 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE SOUTHERN ROCKIES, PLAINS, OHIO VALLEY, & SOUTHEAST...

Surface boundaries/low pressure areas/upper level disturbances are
on this move this period, which along with warming temperatures at
700 hPa/increased mid- level capping across portions of the
Central Plains and IA should broadly limit QPF and flash flood
potential. Wherever cells can manage to train/merge, hourly rain
amounts up to 3" with local totals to 6" would be possible across
the Plains, Ohio Valley, and Southeast, while hourly amounts up to
2" and local totals to 4" would be possible across the Southern
Rockies and Southwest. At the moment, it appears any flash flooding
would be on an isolated to widely scattered basis. In the
Southwest and Southern Rockies, burn scars and dry washes/arroyos
would be most at risk. Anywhere within these regions, urban areas
would be of most concern.

Roth

Day 3 threat area: www.wpc.ncep.noaa.gov/qpf/99epoints.txt

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
253 AM EDT Sat Jul 19 2025


It remains the case that an axis of unsettled weather will remain
in place across the Upper Midwest and also the Southeast U.S. for
the beginning to middle of the week. Thunderstorm complexes
traveling around the northern periphery of the big upper high will
likely produce localized areas of heavy rainfall, potentially
exceeding an inch per hour or more. Therefore, a broad Marginal
Risk area extends from the eastern Dakotas to the western Great
Lakes on Tuesday where a cold front will be intersecting a warm and
humid airmass to the south. There is a good chance that a Slight
Risk could eventually be needed in later outlooks as confidence on
the main QPF axis becomes more certain. Across the Deep South and
northern Florida, a lingering stationary front will help focus deep
moisture with a potential wave of low pressure developing along it,
with some 1-3 inch rainfall totals possible for some areas.
Therefore, a Marginal Risk area is valid here for both Tuesday and
Wednesday.

Heat will once again make weather headlines for much of next week
across a large portion of the southern and central U.S. with a
large upper high becoming anchored over the Mid-South. Widespread
major impacts on the Heat Risk scale are expected from the Central
Plains to the Southeast states early in the week, and these higher
impacts then reach the Midwest and Ohio Valley by mid to late week.
This will be due to widespread highs in the lower 90s to low 100s
for many of these areas, in combination with dewpoints well into
the 70s, and overnight lows remaining uncomfortably warm. This will
likely have some staying power beyond this forecast period based
on the latest week two outlook from the Climate Prediction Center
from the Central Plains to the Gulf Coast region.

Elsewhere across the nation, there should be just enough monsoonal
moisture in place across eastern Arizona and much of New Mexico,
and probably extending into southern portions of Colorado, and
given the potential for some isolated slow moving storms, a
Marginal Risk is in place for both Tuesday and Wednesday. Across
the East Coast region, a cold front is forecast to clear the
Northeast and the Mid-Atlantic region through Tuesday, and
bringing a higher quality airmass after all of the heat and
oppressive humidity lately and lower rain chances. However, the
heat will likely return towards the end of the week as the Canadian
surface high moves offshore and a more southerly flow commences.

Hamrick

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
253 AM EDT Sat Jul 19 2025


It remains the case that an axis of unsettled weather will remain
in place across the Upper Midwest and also the Southeast U.S. for
the beginning to middle of the week. Thunderstorm complexes
traveling around the northern periphery of the big upper high will
likely produce localized areas of heavy rainfall, potentially
exceeding an inch per hour or more. Therefore, a broad Marginal
Risk area extends from the eastern Dakotas to the western Great
Lakes on Tuesday where a cold front will be intersecting a warm and
humid airmass to the south. There is a good chance that a Slight
Risk could eventually be needed in later outlooks as confidence on
the main QPF axis becomes more certain. Across the Deep South and
northern Florida, a lingering stationary front will help focus deep
moisture with a potential wave of low pressure developing along it,
with some 1-3 inch rainfall totals possible for some areas.
Therefore, a Marginal Risk area is valid here for both Tuesday and
Wednesday.

Heat will once again make weather headlines for much of next week
across a large portion of the southern and central U.S. with a
large upper high becoming anchored over the Mid-South. Widespread
major impacts on the Heat Risk scale are expected from the Central
Plains to the Southeast states early in the week, and these higher
impacts then reach the Midwest and Ohio Valley by mid to late week.
This will be due to widespread highs in the lower 90s to low 100s
for many of these areas, in combination with dewpoints well into
the 70s, and overnight lows remaining uncomfortably warm. This will
likely have some staying power beyond this forecast period based
on the latest week two outlook from the Climate Prediction Center
from the Central Plains to the Gulf Coast region.

Elsewhere across the nation, there should be just enough monsoonal
moisture in place across eastern Arizona and much of New Mexico,
and probably extending into southern portions of Colorado, and
given the potential for some isolated slow moving storms, a
Marginal Risk is in place for both Tuesday and Wednesday. Across
the East Coast region, a cold front is forecast to clear the
Northeast and the Mid-Atlantic region through Tuesday, and
bringing a higher quality airmass after all of the heat and
oppressive humidity lately and lower rain chances. However, the
heat will likely return towards the end of the week as the Canadian
surface high moves offshore and a more southerly flow commences.

Hamrick

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
214 PM EDT Wed May 7 2025

Valid 00Z Thu May 08 2025 - 00Z Sun May 11 2025


...Colorado...
Day 1...

Lingering vorticity on the western side of the departing upper low
will still trigger some light snow over the San Juans this evening
before tapering off tonight/early Thursday. WPC probabilities for
at least an additional 4 inches of snow after 00Z are low (10-40%)
above 11,000ft.

For days 2-3, the probability of at least 4 inches of snow is less
than 10%.

The probability of significant freezing rain across the CONUS is
less than 10%.

Note - this is the last regularly scheduled discussion (QPFHSD)
for the 2024-2025 winter season. Unless a significant winter
weather threat emerges, this discussion will next be updated on or
about September 25, 2025.


Fracasso

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
253 AM EDT Sat Jul 19 2025

Valid 12Z Tue Jul 22 2025 - 12Z Sat Jul 26 2025

...Major heat wave building from the Southeast into parts of the
Central U.S. next week and beyond...

...Overview...

The overall weather pattern next week will be dominated by a
building upper level ridge that will be situated over the Deep
South and extending north to the Tennessee and Ohio River valleys.
Heat and humidity build to dangerous levels across much of the
Central U.S. and extending to the Southeast and Deep South. An
active flow pattern will be in place to the north of this high as
multiple shortwave impulses track eastward over the northern tier
states and then New England. A cold front provides some relief
from the recent heat and humidity from the Mid-Atlantic to the
Northeast to start the week, followed by hotter weather mid-week
and beyond. Meanwhile, an upper level trough likely develops near
the West Coast going into early next week.


...Guidance/Predictability Assessment...

The 12Z model guidance suite has a good depiction of the general
weather pattern to start the forecast period Tuesday, and thus a
deterministic model blend works very well as a starting point. The
past few runs of the GFS are more robust with shortwave energy
crossing near the U.S./Canada border and limit the northward extent
of the main upper ridge more so than the overall model consensus
and the AIFS guidance, so its contribution to the preferred blend
was a little less than the CMC and ECMWF models. Elsewhere, there
remain some placement differences with the upper trough that
develops off the California coast late in the week, but it does not
currently appear to have a major effect on the overall forecast.
The ensemble means were gradually increased to about 50% by
Saturday.


...Weather/Hazards Highlights...

It remains the case that an axis of unsettled weather will remain
in place across the Upper Midwest and also the Southeast U.S. for
the beginning to middle of the week. Thunderstorm complexes
traveling around the northern periphery of the big upper high will
likely produce localized areas of heavy rainfall, potentially
exceeding an inch per hour or more. Therefore, a broad Marginal
Risk area extends from the eastern Dakotas to the western Great
Lakes on Tuesday where a cold front will be intersecting a warm and
humid airmass to the south. There is a good chance that a Slight
Risk could eventually be needed in later outlooks as confidence on
the main QPF axis becomes more certain. Across the Deep South and
northern Florida, a lingering stationary front will help focus deep
moisture with a potential wave of low pressure developing along it,
with some 1-3 inch rainfall totals possible for some areas.
Therefore, a Marginal Risk area is valid here for both Tuesday and
Wednesday.

Heat will once again make weather headlines for much of next week
across a large portion of the southern and central U.S. with a
large upper high becoming anchored over the Mid-South. Widespread
major impacts on the Heat Risk scale are expected from the Central
Plains to the Southeast states early in the week, and these higher
impacts then reach the Midwest and Ohio Valley by mid to late week.
This will be due to widespread highs in the lower 90s to low 100s
for many of these areas, in combination with dewpoints well into
the 70s, and overnight lows remaining uncomfortably warm. This will
likely have some staying power beyond this forecast period based
on the latest week two outlook from the Climate Prediction Center
from the Central Plains to the Gulf Coast region.

Elsewhere across the nation, there should be just enough monsoonal
moisture in place across eastern Arizona and much of New Mexico,
and probably extending into southern portions of Colorado, and
given the potential for some isolated slow moving storms, a
Marginal Risk is in place for both Tuesday and Wednesday. Across
the East Coast region, a cold front is forecast to clear the
Northeast and the Mid-Atlantic region through Tuesday, and
bringing a higher quality airmass after all of the heat and
oppressive humidity lately and lower rain chances. However, the
heat will likely return towards the end of the week as the Canadian
surface high moves offshore and a more southerly flow commences.

Hamrick


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw