Weather Prediction Center

National Oceanic and Atmospheric Administration

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
330 AM EDT Wed May 14 2025

Valid 12Z Wed May 14 2025 - 12Z Fri May 16 2025

...Severe thunderstorms and flash flooding possible from the Northern and
Central Plains to the Midwest...

...Dangerous heat in Texas through early next week...

...Elevated to Critical fire weather conditions in the Southwest...

A strong upper level trough will swing across the Central U.S. over the
next couple of days, resulting in a strengthening low pressure system at
the surface. The central low will initially strengthen over the Northern
and Central Plains today, then become occluded on Thursday while tracking
into the Upper Midwest. A warm front will lift north across the
South-Central U.S. while a dry line develops in the Southern Plains, and a
couple of cold fronts will push south and east across the Plains and
Mississippi Valley. This system will produce numerous showers and
thunderstorms across the North-Central U.S., and conditions will be
favorable for strong to severe thunderstorm development in the Northern
and Central Plains today and Midwest on Thursday. Potential severe storm
hazards may include large hail, damaging wind gusts, and tornadoes. Strong
storms may also produce heavy rain that could lead to isolated to
scattered instances of flash flooding.

On Friday, the surface low will linger over the Upper Midwest with
persistent showers throughout the day, while a weakening cold front brings
showers and thunderstorms to the Ohio and Tennessee Valleys. A secondary
cold front is expected to trigger a second wave of showers and
thunderstorms in the Ohio and Mid-Mississippi Valleys Friday afternoon and
evening, and there will be another chance for strong to severe
thunderstorms and isolated flash flooding. This front will also support
some isolated severe storm potential in the Ark-La-Tex region.

Elsewhere, precipitation chances will persist on the backside of the low
pressure system today through Friday morning, with wintry mixed
precipitation and snow possible in the higher elevations of the Northern
and Central Rockies. Meanwhile, a warm front lifting along the East Coast
will bring showers and thunderstorms to the Mid-Atlantic and Ohio Valley
today into Thursday. Precipitation should also return to the Pacific
Northwest late this week as a frontal system slowly approaches the coast.

Conditions across the Southern U.S. will remain mostly dry through the end
of the work week. Dangerously warm high temperatures are expected across
Texas each day through early next week. High temperatures are forecast to
reach 100-110 degrees in portions of Central and South Texas and well into
the 90s elsewhere in the state, which will be dangerous to anyone without
effective cooling and adequate hydration. Overnight lows will be
anomalously warm as well, only dropping down into the 70s, which will
limit overnight relief from the heat.

Warm and dry conditions will also contribute to Elevated to Critical fire
weather conditions in the Southwest today and Thursday. Areas west of the
dryline in the Southern Plains will see relative humidities drop to
critically low values in the single digits and teens, and strong gusty
winds will develop in the wake of deepening low pressure in the Plains.
These conditions will support rapid wildfire spread.


Dolan


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

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
259 AM EDT Wed May 14 2025

Valid 12Z Sat May 17 2025 - 12Z Wed May 21 2025

***Heat builds across the southern Plains while late season snow is
expected for the Rockies***


...General Overview...

A well-organized low pressure system that will initially be over
the northern Great Lakes on Saturday will likely develop a triple
point low over New England by Sunday before moving offshore,
bringing widespread rain to the Northeast states. Out West, an
amplified upper trough develops over the Great Basin and this spurs
surface cyclogenesis across the central Plains by Monday,
supporting widespread coverage of showers and thunderstorms from
the western High Plains to the Mid-South to start next week. This
surface low then tracks in the general direction of the Great Lakes
by next Wednesday, while a weaker disturbance affects the
Northwestern states.


...Guidance/Predictability Assessment...

The 00Z model guidance suite today continues to offer very good
synoptic scale agreement for the upcoming weekend, with a multi-
deterministic model blend sufficing as a starting point in the
forecast process and slightly more weighting applied to the
ECMWF/GFS solutions. Guidance agrees well with another trough
amplifying over the West this weekend, with an eventual closed low
located over/near the central Great Basin. This low will eventually
lift northward into the north-central U.S. early next week but
with plenty of uncertainty in energy dispersion within and around
low which would have implications on sensible weather across this
region. The WPC forecast trended towards half ensemble means by the
middle of next week which showed better consistency and smoothed
out the smaller scale differences.


...Weather/Hazards Highlights...

Showers and thunderstorms increase in coverage and intensity
from the southern Plains and extending to the Mid-South over the
weekend with enhanced moisture convergence near quasi-stationary
frontal boundary and ahead of a developing wave of low pressure
near the Texas Panhandle. The guidance suggests multiple rounds of
convection across the region, but differ on QPF placement, so a
broad Marginal Risk area is valid for portions of this region on
both Saturday and Sunday. Anomalous moisture combined with low
flash flood guidance values across parts of the Northeast allowed
for the continuation of a Marginal Risk area for the Day
4/Saturday ERO for this region ahead of a departing front and
redevelopment of low pressure offshore, and moisture lingers across
eastern Maine where a Marginal Risk is planned for Sunday.

Across the Rockies, expect additional chances for late season snow
for the central and northern Rockies by Sunday into early next
week
as the next upper trough and shortwave moves in, with the potential
for over a foot of accumulation for some of the highest mountain
ranges. Widespread moderate to locally heavy rainfall seems likely
to develop across the Great Basin over the weekend and into the
north-central U.S. early next week in response to the developing
upper low which will continue to be monitored. A Marginal Risk area
is planned for Sunday/Day 5 across portions of eastern Nevada,
southwest Utah, and northern Arizona where slow moving convection
associated with the upper low may result in some localized flooding
across the high desert. Another area of enhanced rainfall is
looking more likely across the northwestern High Plains on Sunday
as well with increased moisture flux to the north of the developing
surface low ejecting east from the Rockies, and a Marginal Risk
area is also planned for this area on Sunday.

Early season excessive heat is expected across central and southern
Texas through the upcoming weekend with highs exceeding 100
degrees near the Rio Grande and into much of central Texas, and
HeatRisk reaching the major to extreme category for some of these
areas. This will likely set additional record high temperatures for
these areas, and overnight lows will struggle to fall below 75
degrees for many of these same areas. In contrast, chilly
conditions are likely for the Intermountain West and Northern
Rockies/Plains with highs running 10 to perhaps 20 degrees below
average for many areas from Arizona to Idaho with the upper level
trough and increased cloud cover.

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
351 AM EDT Wed May 14 2025

Valid 00Z Thu 15 May 2025 - 00Z Thu 22 May 2025

Hawaii will generally be on the southwestern periphery of a large
surface high through the remainder of this week and into the
weekend. The ensemble means suggest a col will develop within the
subtropical ridge axis by next weekend north of the far
northwestern Islands with a weakening cold front approaching that
region by next Sunday, but that front stays west of the main
Islands and keeps any impactful weather away.

Low level trade wind flow should generally be out of the east most
days, with perhaps some ESE component next weekend. The usual
terrain enhanced showers can be expected most days across the
Islands, with greater coverage over the Big Island, but no major
rainfall events are expected over the next week.

Hamrick

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
333 AM EDT Wed May 14 2025
Day 1
Valid 12Z Wed May 14 2025 - 12Z Thu May 15 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE NORTHERN PLAINS AND MID-ATLANTIC...

...Northern Plains...

A deep upper level trough centered over the Intermountain West this
morning will become negatively tilted as an impressive shortwave
draws plentiful upper level energy into the northern Plains.
Surface cyclogenesis is expected ahead of this trough over Kansas,
which will track NNE into south-central North Dakota by Thursday
morning. A line of convection associated with the leading/eastern
edge of the trough is moving into far western South Dakota from
Wyoming, and this line of storms will track NNE over the western
Dakotas through the morning. The primary flooding threat will be
from a new line of storms which will develop over western South
Dakota with peak heating this afternoon, then track very slowly
eastward, as embedded cells move north, parallel to the line. This
will result in some training of convection, leading to an isolated
flash flooding threat.

In coordination with UNR/Rapid City, SD; FSD/Sioux Falls, SD; and
ABR/Aberdeen, SD forecast offices, the inherited Slight Risk was
removed with this update, and the surrounding Marginal shifted well
to the west of inherited. The westward shift was due largely to a
shift in the guidance slowing the forward motion of the trough.
While this increased forecast rainfall amounts some, the area of
the Dakotas now highlighted is in Moderate to in some localized
cases Severe drought. Nasa Sport soil moisture imagery shows the
area has next to no moisture. Thus, despite the potential for heavy
rainfall at times in some areas, the flooding threat was determined
to be isolated.

...Mid-Atlantic...

Lingering moisture from a slow moving storm system associated with
a weak upper level negatively tilted trough along with MUCAPE
values in the area between 1,000 and 1,500 J/kg this afternoon will
lead to a renewed round of showers and thunderstorms across much of
the Mid-Atlantic. Due to the movement of the trough however, the
storms should be rather progressive, which will limit the amount of
rainfall any one area sees. While the entire area has picked up 1-2
inches of rain yesterday, thoroughly saturating the near-surface
soils, expect most areas to see less than an inch of new rain.
Those localized areas under the stronger storms may perhaps
approach an inch of new rainfall. This should keep flash flooding
isolated and localized, albeit with some uncertainty. For now the
area remains in a higher end Marginal with few changes from
inherited. 00Z HREF guidance shows a high probability of exceeding
3 and 6 hour FFGs from far western Maryland southeast to the
Tidewater of Virginia with these storms and low FFGs, but it
remains unclear as to the impacts from the resultant flooding given
the significantly lower amounts of rain expected today as compared
with yesterday.

Wegman

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

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
333 AM EDT Wed May 14 2025
Day 2
Valid 12Z Thu May 15 2025 - 12Z Fri May 16 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE NORTHERN PLAINS...

The low over the northern Plains will become vertically stacked as
the upper trough catches up with the surface low. With the new
vertically stacked low moving only very slowly towards the
northeast, this will make for a prolonged period of rain on the
cold/northwest side of the center, as it becomes the comma head
region of the low. This area of the low is expected to be largely
devoid of convection given the lack of instability making it quite
that far north and west. Thus, expect the 2-3 inches of additional
rainfall from today to have only a minimal impact given the still
largely dry soils over much of North Dakota. This Marginal was
shifted well to the west following the latest guidance trends, so
the Marginal was removed from much of Minnesota due to lack of
expected rainfall.

Wegman

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

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
333 AM EDT Wed May 14 2025
Day 3
Valid 12Z Fri May 16 2025 - 12Z Sat May 17 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE MIDWEST, TENNESSEE VALLEY, AND OZARKS...

A potent shortwave trough will round the periphery of the
vertically stacked low over the northern Plains and upper Great
Lakes on Friday. This shortwave will tap into a low level jet of
Gulf moisture riding the prior low's occluded front. This will
reinvigorate the front, resulting in rather fast northeastward
moving storms across the Marginal Risk area. Much of this area
remains saturated for soil moisture from recent prior storms, so
any training thunderstorms will be capable of producing isolated
flash flooding. There is poor agreement on the character of the
storms, which better agreement may have warranted a Slight Risk
upgrade in part due to the wet soils in this area. For now, will
continue to monitor the trends in the rainfall guidance for better
indication on if a Slight Risk upgrade is needed.

Wegman

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

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
259 AM EDT Wed May 14 2025


Showers and thunderstorms increase in coverage and intensity
from the southern Plains and extending to the Mid-South over the
weekend with enhanced moisture convergence near quasi-stationary
frontal boundary and ahead of a developing wave of low pressure
near the Texas Panhandle. The guidance suggests multiple rounds of
convection across the region, but differ on QPF placement, so a
broad Marginal Risk area is valid for portions of this region on
both Saturday and Sunday. Anomalous moisture combined with low
flash flood guidance values across parts of the Northeast allowed
for the continuation of a Marginal Risk area for the Day
4/Saturday ERO for this region ahead of a departing front and
redevelopment of low pressure offshore, and moisture lingers across
eastern Maine where a Marginal Risk is planned for Sunday.

Across the Rockies, expect additional chances for late season snow
for the central and northern Rockies by Sunday into early next
week
as the next upper trough and shortwave moves in, with the potential
for over a foot of accumulation for some of the highest mountain
ranges. Widespread moderate to locally heavy rainfall seems likely
to develop across the Great Basin over the weekend and into the
north-central U.S. early next week in response to the developing
upper low which will continue to be monitored. A Marginal Risk area
is planned for Sunday/Day 5 across portions of eastern Nevada,
southwest Utah, and northern Arizona where slow moving convection
associated with the upper low may result in some localized flooding
across the high desert. Another area of enhanced rainfall is
looking more likely across the northwestern High Plains on Sunday
as well with increased moisture flux to the north of the developing
surface low ejecting east from the Rockies, and a Marginal Risk
area is also planned for this area on Sunday.

Early season excessive heat is expected across central and southern
Texas through the upcoming weekend with highs exceeding 100
degrees near the Rio Grande and into much of central Texas, and
HeatRisk reaching the major to extreme category for some of these
areas. This will likely set additional record high temperatures for
these areas, and overnight lows will struggle to fall below 75
degrees for many of these same areas. In contrast, chilly
conditions are likely for the Intermountain West and Northern
Rockies/Plains with highs running 10 to perhaps 20 degrees below
average for many areas from Arizona to Idaho with the upper level
trough and increased cloud cover.

Hamrick

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
259 AM EDT Wed May 14 2025


Showers and thunderstorms increase in coverage and intensity
from the southern Plains and extending to the Mid-South over the
weekend with enhanced moisture convergence near quasi-stationary
frontal boundary and ahead of a developing wave of low pressure
near the Texas Panhandle. The guidance suggests multiple rounds of
convection across the region, but differ on QPF placement, so a
broad Marginal Risk area is valid for portions of this region on
both Saturday and Sunday. Anomalous moisture combined with low
flash flood guidance values across parts of the Northeast allowed
for the continuation of a Marginal Risk area for the Day
4/Saturday ERO for this region ahead of a departing front and
redevelopment of low pressure offshore, and moisture lingers across
eastern Maine where a Marginal Risk is planned for Sunday.

Across the Rockies, expect additional chances for late season snow
for the central and northern Rockies by Sunday into early next
week
as the next upper trough and shortwave moves in, with the potential
for over a foot of accumulation for some of the highest mountain
ranges. Widespread moderate to locally heavy rainfall seems likely
to develop across the Great Basin over the weekend and into the
north-central U.S. early next week in response to the developing
upper low which will continue to be monitored. A Marginal Risk area
is planned for Sunday/Day 5 across portions of eastern Nevada,
southwest Utah, and northern Arizona where slow moving convection
associated with the upper low may result in some localized flooding
across the high desert. Another area of enhanced rainfall is
looking more likely across the northwestern High Plains on Sunday
as well with increased moisture flux to the north of the developing
surface low ejecting east from the Rockies, and a Marginal Risk
area is also planned for this area on Sunday.

Early season excessive heat is expected across central and southern
Texas through the upcoming weekend with highs exceeding 100
degrees near the Rio Grande and into much of central Texas, and
HeatRisk reaching the major to extreme category for some of these
areas. This will likely set additional record high temperatures for
these areas, and overnight lows will struggle to fall below 75
degrees for many of these same areas. In contrast, chilly
conditions are likely for the Intermountain West and Northern
Rockies/Plains with highs running 10 to perhaps 20 degrees below
average for many areas from Arizona to Idaho with the upper level
trough and increased cloud cover.

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
259 AM EDT Wed May 14 2025

Valid 12Z Sat May 17 2025 - 12Z Wed May 21 2025

***Heat builds across the southern Plains while late season snow is
expected for the Rockies***


...General Overview...

A well-organized low pressure system that will initially be over
the northern Great Lakes on Saturday will likely develop a triple
point low over New England by Sunday before moving offshore,
bringing widespread rain to the Northeast states. Out West, an
amplified upper trough develops over the Great Basin and this spurs
surface cyclogenesis across the central Plains by Monday,
supporting widespread coverage of showers and thunderstorms from
the western High Plains to the Mid-South to start next week. This
surface low then tracks in the general direction of the Great Lakes
by next Wednesday, while a weaker disturbance affects the
Northwestern states.


...Guidance/Predictability Assessment...

The 00Z model guidance suite today continues to offer very good
synoptic scale agreement for the upcoming weekend, with a multi-
deterministic model blend sufficing as a starting point in the
forecast process and slightly more weighting applied to the
ECMWF/GFS solutions. Guidance agrees well with another trough
amplifying over the West this weekend, with an eventual closed low
located over/near the central Great Basin. This low will eventually
lift northward into the north-central U.S. early next week but
with plenty of uncertainty in energy dispersion within and around
low which would have implications on sensible weather across this
region. The WPC forecast trended towards half ensemble means by the
middle of next week which showed better consistency and smoothed
out the smaller scale differences.


...Weather/Hazards Highlights...

Showers and thunderstorms increase in coverage and intensity
from the southern Plains and extending to the Mid-South over the
weekend with enhanced moisture convergence near quasi-stationary
frontal boundary and ahead of a developing wave of low pressure
near the Texas Panhandle. The guidance suggests multiple rounds of
convection across the region, but differ on QPF placement, so a
broad Marginal Risk area is valid for portions of this region on
both Saturday and Sunday. Anomalous moisture combined with low
flash flood guidance values across parts of the Northeast allowed
for the continuation of a Marginal Risk area for the Day
4/Saturday ERO for this region ahead of a departing front and
redevelopment of low pressure offshore, and moisture lingers across
eastern Maine where a Marginal Risk is planned for Sunday.

Across the Rockies, expect additional chances for late season snow
for the central and northern Rockies by Sunday into early next
week
as the next upper trough and shortwave moves in, with the potential
for over a foot of accumulation for some of the highest mountain
ranges. Widespread moderate to locally heavy rainfall seems likely
to develop across the Great Basin over the weekend and into the
north-central U.S. early next week in response to the developing
upper low which will continue to be monitored. A Marginal Risk area
is planned for Sunday/Day 5 across portions of eastern Nevada,
southwest Utah, and northern Arizona where slow moving convection
associated with the upper low may result in some localized flooding
across the high desert. Another area of enhanced rainfall is
looking more likely across the northwestern High Plains on Sunday
as well with increased moisture flux to the north of the developing
surface low ejecting east from the Rockies, and a Marginal Risk
area is also planned for this area on Sunday.

Early season excessive heat is expected across central and southern
Texas through the upcoming weekend with highs exceeding 100
degrees near the Rio Grande and into much of central Texas, and
HeatRisk reaching the major to extreme category for some of these
areas. This will likely set additional record high temperatures for
these areas, and overnight lows will struggle to fall below 75
degrees for many of these same areas. In contrast, chilly
conditions are likely for the Intermountain West and Northern
Rockies/Plains with highs running 10 to perhaps 20 degrees below
average for many areas from Arizona to Idaho with the upper level
trough and increased cloud cover.

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