Weather Prediction Center

National Oceanic and Atmospheric Administration

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
349 AM EDT Tue Jun 24 2025

Valid 12Z Tue Jun 24 2025 - 12Z Thu Jun 26 2025

...Extremely dangerous heat persists from the Midwest to East Coast this
week...

...There is a moderate risk of excessive rainfall leading to flash
flooding across much of central New Mexico today...

...Additional excessive rainfall and severe thunderstorm concerns from the
Front Range to the Midwest...


A strong upper ridge centered over the East will generate a dangerous heat
wave this week. Extreme heat warnings and/or heat advisories currently
extend from the Lower Mississippi Valley and Midwest to the East Coast,
affecting nearly 160 million people. Extreme heat is expected to last
through much of this week with the longest duration of well above average
temperatures centered over the eastern Ohio Valley into Friday. Numerous
daily record highs and warm low temperatures are expected from the Midwest
through much of the East Coast through Wednesday. Widespread high
temperatures are forecast to reach the upper 90s, with triple digits
possible along the East Coast. Meanwhile, overnight lows are forecast to
only drop into the 70s, with urban centers along the East Coast struggling
to drop below 80 degrees at night. The most significant cumulative heat
impacts are anticipated across the Mid-Atlantic through Thursday and
eastern Ohio Valley into Friday, leading to several consecutive days of
oppressive heat. This will exacerbate the heat health impacts especially
by midweek. This level of heat can be dangerous to anyone without adequate
cooling and/or hydration. Heat related illnesses increase significantly
during long duration heat waves such as this. Take action when you see
symptoms of heat exhaustion and heat stroke.

Another area of concern is in the Central U.S., where an upper trough with
shortwave energy riding along its leading edge will produce thunderstorms
and heavy rainfall. Anomalous moisture interacting with the aforementioned
shortwave energy and a surface trough/dryline will produce storms across
New Mexico tonight. A moderate risk (at least 40%) of excessive rainfall
leading to flash flooding is in effect for central New Mexico today, where
many areas are likely to receive over 1.5 inches. Sensitive burn scar
areas in the Sacramento Mountains are especially susceptible to flash
flooding from heavy rainfall. Upslope areas of the southern Sangre de
Cristo Mountains are also particularly vulnerable to flash flooding today.
A slight risk (at least 15%) of excessive rainfall remains over central
New Mexico on Wednesday, with the Sacramento Mountains being of particular
concern yet again. Plenty of cloud cover from the troughing and storms
will drop daytime highs to between 20-30 degrees below average.

A quasi-stationary front draped across the Central Plains and Midwest will
support thunderstorms, some isolated severe, and the potential for
excessive rainfall through Wednesday. There's a slight risk of excessive
rainfall extending from northeastern Colorado to southern
Wisconsin/northern Illinois today. Moisture presence increases on
Wednesday, so a higher end slight risk is in effect from southern Nebraska
to eastern Wisconsin. The Storm Prediction Center issued a slight risk
(level 2/5) of severe thunderstorms across parts of the Central/Northern
High Plains where storms associated with very large hail and severe wind
gusts will be likely this afternoon and evening. The severe threat shifts
into the Southeast on Wednesday as a mid-level vortex retrogrades into the
Florida Peninsula from the western Atlantic. SPC issued a pair of slight
risk areas, one over the Carolinas and one across southern Alabama/Florida
panhandle. Severe wind gusts will be possible for much of the Southeast as
a result.


Kebede


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

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
303 AM EDT Tue Jun 24 2025

Valid 12Z Fri Jun 27 2025 - 12Z Tue Jul 01 2025

...Record heat is less likely by late week, but dangerous heat
continues for the Ohio Valley, Mid-South, and
Mid-Atlantic/Carolinas...

...Overview...

Into late week, the peak of the significant and extremely
dangerous heat wave will have waned. However, temperatures will
remain quite hot across the Ohio Valley back toward the Mid-South
and east toward the Mid-Atlantic and Carolinas as some weaker upper
ridging persists. The long duration of the heat wave will cause
exacerbated impacts, maintaining Major to Extreme HeatRisk in some
of these areas into late week and the weekend. Meanwhile, moisture
will advect north and then east around the broad southeastern U.S.
ridge in a "ring of fire" setup. Better chances for flash flooding
are now into the short range period, but a wavy frontal boundary
interacting with the remaining above average moisture could allow
for localized heavy rain and flash flooding across the central
Appalachians to Northeast Friday-Saturday. Additional rounds of
scattered thunderstorms are possible across much of the central and
eastern U.S. into the weekend and early next week, some of which
could have low-end heavy rain and flooding potential.


...Guidance/Predictability Assessment...

Model guidance continues to be agreeable in showing mean ridging
across the southeastern U.S. late week (though weaker compared the
near term) and expanding west over the weekend and early next week.
This creates a more zonal pattern across the country with the jet
stream staying in the northern tier. This puts much more emphasis
on the speed, depth, and evolution of individual shortwaves, which
can be more difficult to nail down at extended time ranges. The
first shortwave and weak surface low atop the Great Lakes seems to
show reasonable consensus but any seemingly minor waffling of the
features would lead to sensible weather differences, like the bulk
of QPF moving across the northern U.S. or southern Canada. Then the
next broader, but still shallow, trough should be coming across
the Northwest Friday and reach the north-central U.S. by Sunday.
For this feature, the main outlier was the 18Z GFS, which was
slower to bring the trough east while western Canadian energy gets
involved. The other operational models, including the 12Z GFS and
the new 00Z GFS, were more agreeable. Various AI/ML models show
some spread though, so adjustments may need to be made in the
future. The flow pattern may amplify a bit into next week as that
trough shows a little digging. Meanwhile ridging is forecast to
build with its axis along the Rockies or so, while a southern
stream trough gradually approaches California while a northeastern
Pacific upper low may send (uncertain) shortwaves toward the
Northwest.

The WPC forecast was initially based on a composite blend of the
12Z deterministic guidance. By Day 5-7, introduced and gradually
increased the proportion of the EC and GEFS ensemble means to
around half to lessen the influence of individual model
variability.


...Weather/Hazards Highlights...

Moisture advection around the southeastern U.S. upper ridge
combined with shortwaves aloft and a wavy frontal boundary will
provide a favorable environment for convection for portions of the
northern tier into late week. An initial wave moving across the
Lower Great Lakes and Northeast Friday-Saturday will allow for some
possibly heavy rain in the Interior Northeast on the cusp of the
instability gradient and where a weak surface low tracks along the
front. Have Marginal Risks delineated in the Day 4/Friday and Day
5/Saturday EROs for localized flash flooding with this activity.
Farther south, showers and thunderstorms will become scattered to
widespread through much of the period across the eastern third of
the lower 48, mostly diurnally driven in the warm and unstable
airmass. There looks to be some thunderstorm focus stretching
across the central Appalachians especially Friday, so will
encompass that area within the Marginal Risk Day 4 ERO as well.
Will continue to monitor any other areas that show enhanced rain
totals that could trigger flash flood concerns. The central Gulf
Coast may see a few days of more focused convection, with heavier
amounts possible early next week (after the ERO period, and would
have to battle against high flash flood guidance to see flooding
concerns there).

Another shallow upper trough and frontal system will push through
the north-central U.S. late week into the weekend, providing
forcing for thunderstorms. Instability is likely to be high (MUCAPE
of 3000-5000 J/kg already shown by the global models...even higher
farther south, but where there is a drier atmosphere that could be
capped). Have Marginal Risks delineated in parts of the Dakotas
into the Upper Midwest on Friday and Saturday since locally heavy
rain rates are likely in this unstable atmosphere. Convection is
forecast to shift southeast across the Midwest and central
Plains/Middle Mississippi Valley early next week ahead of the
trough and front.

After a very wet short range period, support for heavy rain in New
Mexico will be waning by late week. However, any showers and
thunderstorms that form could be problematic for sensitive areas
like burn scars and terrain, especially considering the wet
antecedent conditions by then. Thus show a Marginal Risk for the
Sacramento Mountains and vicinity into Friday for isolated flash
flooding. Rain will continue to decrease in coverage and amounts on
Saturday. But into early next week, monsoonal moisture looks to
increase, bringing rain and thunderstorm chances to the southern
and central Rockies and High Plains.

The strong upper high/ridge stretching across the south-central to
eastern U.S. will be weaker by late week but remain generally in
place, maintaining hot temperatures albeit slightly moderated from
the short range period and less likely to break records.
Nevertheless, temperatures will be well into the 90s in many
central and eastern areas, while dewpoints in the 70s will raise
heat indices into the 100s. Overnight lows will only drop into the
low/mid 70s for many areas, bringing little relief from the heat
and exacerbating potential impacts. Especially after the extreme
heat in the short range, through late week HeatRisk values will be
Extreme for portions of the Ohio Valley, and Major from the Mid-
South into the southern Mid-Atlantic -- levels 3 and 4 on a scale
from 1 to 4 (4 being Extreme). This indicates an intensity and
duration of heat that is extremely dangerous to anyone without
adequate cooling or hydration. Extreme heat is the number 1
weather-related killer -- please take precautions if you are
outside during the hottest part of the day and seek cooling if you
are without adequate means. Into the weekend and early next week,
temperatures should slowly moderate in the east-central U.S. in
particular for closer to normal summer heat. Areas like the Mid-
Atlantic are expected to stay hot most days with generally Major
HeatRisk. Meanwhile the Northeast should see relief from the heat
by the medium range period behind a backdoor front, but could
gradually warm early next week. The north-central U.S. can expect
warmer than average temperatures by 5 to 10 degrees around Friday-
Saturday and then cool behind a cold front. Temperatures in the
Northwest will warm by early next week under an upper ridge. The
Desert Southwest can expect typical summer heat with temperatures
in the 100s and 110s.


Tate


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
346 AM EDT Tue Jun 24 2025

Valid 00Z Wed 25 Jun 2025 - 00Z Wed 02 Jul 2025

Easterly trade winds will gradually decrease over the next couple
of days as the surface high centered northeast of Hawaii weakens.
Generally moderate winds are forecast to last through the weekend
into early next week. Meanwhile aloft, a weak upper trough will
retrograde across the state and may allow for a raised inversion
while waves of higher moisture move through. This should lead to a
comparatively wetter trade wind pattern through much of the week,
especially for Kauai and vicinity where enhanced moisture lingers
the longest. By the weekend a mid/upper high may sneak into at
least the eastern islands and suppress any widespread showers, but
some passing windward and mauka showers remain possible this
weekend into early next week.

Tate

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
856 PM EDT Mon Jun 23 2025
Day 1
Valid 01Z Tue Jun 24 2025 - 12Z Tue Jun 24 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
NEW MEXICO AND WEST TEXAS, AND FROM KANSAS INTO SOUTHERN
WISCONSIN...

01Z Update...
Based on current observation trends, as well as recent hi-res
guidance, removed much of the Marginal Risk area previously
covering the central High Plains, and brought the northern edge of
the Marginal Risk further south across the central Plains into the
Upper Midwest. Made mostly minor adjustments to the Slight Risk
areas, where the potential for heavy rain and flash flooding is
expected to continue through the evening into the overnight. Recent
runs of the HRRR and the 18Z HREF indicate the greatest threat for
widespread heavy amounts extends from northeastern Kansas, through
northwestern Missouri, into southern Iowa. Training storms are
expected to continue, with the 18Z HREF showing high neighborhood
probabilities (greater than 80 percent) for accumulations over 2
inches, and greater than 50 percent for accumulations exceeding 3
inches in this area.

Pereira

16Z Excessive Rainfall Discussion Update... Based on the 06Z
neighborhood probabilities...and a quick look at the probabilities
from the 12Z run...extended the Slight Risk area a bit to the east
to cover more of southern Wisconsin. In the broader picture...the
risk of excessive rainfall exists on the periphery of a broad upper
level ridge from New Mexico and West Texas...across the Central
Plains into the Upper Midwest given the persistent deep-layer
advection and embedded shortwave energy. The 12Z HREF probabilities
aligned well with the previously issued Excessive Rainfall Outlook
and only minor adjustments were needed.

Bann


...New Mexico into West Texas...

A general pattern of persistence will maintain a relevant posture
for scattered to widespread convective impacts across Southwestern
TX up through the eastern half of NM with the highest potential
impacts aligned within the terrain. Ample moisture advection
provided by prevailing southerly-oriented flow within the sfc-500mb
layer will correlate with an environment capable of locally heavy
rainfall within any cell maturation across the above areas. The
proxy of the deep layer moisture and RER jet dynamics from the mean
trough situated to the west will create an accumulated risk of
showers and storms propagating over the same areas leading to
increasingly compromised soils, or even interacting with the
already prevalent burn scars situated over the Sacramento Mtns.
Storm motions will likely be fairly weak as noted by the forecast
Corfidi vectors residing between 5-15kts on average within the
confines of the entire Southwest TX and Southeast NM domains. This
will allow for modest training concerns that will ultimately cause
problems if they fall within any of the urban centers along the
Upper Trans Pecos out into the complex topography located in the
region. The best chance for flash flooding will likely be within
those burn scar locations where hydrophobic soils are still a
problem and can promote a formidable runoff regime that could cause
significant problems locally if a heavy cell forms overhead. Areas
within the Pecos river are also notorious for flash flooding
capabilities due to the limited drainage structures prevalent
within town limits. Considering the HREF neighborhood probs for >2"
are running between 50-90% over a large area extending from the
Davis Mtns up through the Eastern NM Caprock, the previous SLGT
risk was upheld with wording of a higher end SLGT considering the
environment in place.

...Central Plains to Midwest...

The Central Plains through the Midwest continues to lie within the
northern and northwest periphery of a broad ridge extension
centered over the Mid Atlantic. The proxy of the ridge has allowed
for a persistent south to southwesterly mean flow within the
column leading to steady moisture advection within the boundary
layer up to around 500mb. Current PWATs from 00z RAOB analysis
across the Plains and Mississippi Valley denote moisture anomalies
that are approaching +2 deviations, something that has also been
reflected in the last several days of NAEFS anomalies within the
ensemble suite. The relevant moisture pooling across the zone
extending from KS up into the Midwest will lead to a formidable
widespread convective initiation scheme that will develop due to
increased convergence along and ahead of a slow-moving cold front
nosing down through the Northern Plains. The interaction of the
cold front with a very buoyant environment (MUCAPE 2500-4000 J/kg)
located across the Central Plains up into the Upper Mississippi
Valley will create a broad axis of heavy convection with the
heaviest precip likely correlated with the 2+" PWAT domain located
from North-Central KS and points northeast into IA.

There's a general consensus within the latest CAMs suite of
significant totals between 2-4" forecast located within the
aforementioned zone, including some deterministic output and lower
neighborhood prob correlation for some places exceeding 5". The
prospects for those types of totals stems from not only the
favorable deep moist convective pattern, but also the mean layer
flow and surface convergence regime along the front creating a
favorable environment for back-building convection and training
cell prospects. This is fairly well-documented when assessing
forecast Corfidi Vectors continuing this divergent storm motion
setup within the upshear and downshear calculations given the
forecast wind field(s). A strong RER jet dynamic will only aid in
a blossoming QPF field and maintenance as the mean flow takes the
convective pattern off to the northeast. This pattern will carry
through Monday evening into early Tuesday morning with some
weakening of the convective field anticipated due to loss of
diurnal destabilization. In any case, this setup is capable of
widespread 1-2" totals with the hardest hit locations likely seeing
2-4" with locally higher as noted in the latest CAMs. The saving
grace, at least initially for D1, are the drier soils centered over
the Central Plains into parts of Southeast NE and Southwest IA
leading to higher FFG indices that will need some priming in order
to likely reflect a more significant flash flood response.

The change from the previous forecast was an adjustment to the
south with the overall SLGT risk as guidance reflects a bit of a
faster frontal progression than anticipated. This places a higher
risk a bit south over Northeast KS to points northeast. The threat
for locally heavy rainfall is also forecast across Southwest KS
with cells ejecting out of the High Plains of CO/NM, but CAMs are
less defined due to the lack of a boundary layer focus
comparatively. The MRGL exists in at particular area, but if CAMs
come into agreement on a local max centered near or southwest of
DDC, then the SLGT risk may be extended further to the southwest to
account for the prospect.

Kleebauer


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

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
408 AM EDT Tue Jun 24 2025
Day 1
Valid 12Z Tue Jun 24 2025 - 12Z Wed Jun 25 2025

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
CENTRAL AND SOUTHERN NEW MEXICO...

...New Mexico...

A massive 597dm ridge centered over the Ohio Valley and Mid
Atlantic will flex further as we head into Tuesday with the higher
heights on the western fringes pushing back west beyond the
eastern portions NM. A steady north- south progression within the
mid and upper levels will send numerous smaller shortwave
perturbations poleward with anticipated motions into the
Sacramento's, eventually north into the Sangre de Cristos by the
late-afternoon and evening period today. Anomalous moisture ranking
in the 99th percentile via NAEFS and ECENS Climatological
percentiles will remain parked over the region the next 24-36 hrs
and will couple with the focused ascent and narrow upslope proxy
within the Sacramento Mtns. This will translate to a corridor of
heavy convection remaining situated in- of the terrain beginning
late this morning and carrying through peak diurnal instability.
Consensus within all deterministic and relevant ensembles agree
that local topographic effects within this pattern will yield some
significant rainfall potential over areas that are prone to flash
flooding, especially with the burn scars still present near Ruidoso
creating higher runoff capabilities. 00z HREF neighborhood
probabilities were elevated for the >3" (60-80%) and >5" (30-60%)
prospects within the Sacramento's for the period. The biggest
difference is the increased probs for those similar thresholds for
areas west of the Sacramento's, encroaching on places northeast of
the Bootheel into Southern NM.

The difference the past 24 hrs. has been the expected influence of
the approaching trough out west providing a reinforcement of the
trailing upper jet with the amplitude of the pattern creating more
room further west for large scale ascent, and moisture advection
back into the western half of NM, even sneaking into Southeast AZ.
The entire evolution will likely spur scattered to widespread
thunderstorm activity over the aforementioned regions with cold
pool mergers from storms likely to produce some upscale growth in
the evening as the convergence of cold pools will act to spawn more
multi-cell modes. A lot of the deterministic now has locally 2-4"
across places like the San Mateo Mtns. and adjacent deserts
stemming from the convective clusters propagating eastward over the
second half of the forecast cycle. These areas are prone to any
type of heavy rainfall, and given the highly anomalous environment,
1-2"/hr rates are certainly in the cards. This threat will linger
through the overnight time frame before finally settling closer to
Wednesday AM.

Further north, the signal for heavy rainfall continues into the
Sangre de Cristos where the afternoon and evening time frames call
for widespread heavy thunderstorm activity aligned with the ridges
of the southern Rockies. These areas also have burn scar prevalence
that could exacerbate flash flood risks as runoff capabilities are
maximized. 24hr 100yr ARI exceedance probabilities are highest
across Central and Southern NM, but a small axis of >20% probs
remains parked over the Sangre de Cristos north of Santa Fe. 10yr
ARI exceedance probs are between 60-80% for the same area (90+%
over the Sacramento's), so the threat is within the upper echelon
of the prob fields leading to a higher chance of significant
impacts over the complex terrain and remnant burn scars.

The previous MDT risk was expanded westward to include those areas
that could see locally as much as 2-4" in any storm impacts this
afternoon and evening lasting into early Wednesday. A high-end MDT
is forecast for the Sacramento and Sangre de Cristo Mtns. in NM.
High end SLGT risk is forecast for El Paso proper and surrounding
suburbs. There's a chance the threat for El Paso trends more
impactful, so be sure to check in with the latest updates in the
next forecast package for a potential upgrade over the urban
center.

...Central Plains to Midwest...

Current radar/sat composite shows an extensive line of convection
extending from southwest to northeast out of KS to as far north as
Central WI. The setup for the convective pattern lies within the
northern periphery of a ridge and along a quasi-stationary front
bisecting the areas above. Smaller shortwaves rounding the western
flank of the ridge will continue riding over top the front
creating focused areas of showers and thunderstorms through the
first 6hrs of the period with some areas over far Northeast KS into
Northwest MO and Southern IA seeing a continuation of locally
heavy rainfall bleeding into the new D1. This area is the focus
initially for flash flood impacts with saturated grounds likely to
struggle to withstand the initial batch of storms that push
through. Thankfully, there will be a small "break" in the
persistence of the convective pattern moving into the late-morning
and afternoon, but still some scattered shower/storm development
will be forecast during the prime destabilization period, so the
threat for isolated flash flooding will carry through the daytime.

By the evening, the focus of the convective pattern shifts back
west and southwest with an ejection of a potent shortwave out of
the Southern High Plains and Front Range of the Rockies. With ample
instability presence across the Central Plains into the Midwest
along the quasi-stationary front, a second convective onslaught is
forecast to materialize likely beginning between 20-00z, carrying
east and northeast through the remainder of the forecast. At the
same juncture, a strong 700-900 kg/ms IVT pulse will be advecting
northeastward into the Central Plains and Midwest during the time
frame of interest (00-12z Wednesday), so the heavy rain threat with
2-3"/hr rates will certainly have potential for basically anywhere
in the Central Plains/Midwest domain. There's a growing consensus
on the area positioned over Southern SD, much of NE, and parts of
KS being the initial beneficiary of the convective development
which could lead to scattered flash flood prospects within a 6hr
window upon initiation. As we move into the evening, nocturnal LLJ
will spawn in-of the High Plains arcing northeast into parts of the
Midwest allowing the stationary front to begin lifting north in
the form of a warm front. The mean layer flow will begin to orient
more parallel to the front itself creating an environment capable
for cells to mature and begin training over areas within proxy to
the boundary. Guidance has been subject to bouncing around on
exactly where this may occur, but 00z CAMs have come into a
reasonable agreement on an axis extending over Eastern NE,
including the Omaha metro, through Western IA. This is correlated
with the higher neighborhood probs for >2" (50-70%) aligned over
the area with the >3" signal pretty respectable (40-60%) over the
same area. The highest probs and overlap of heavy precip within the
CAMs is surprisingly directly over Omaha and surrounding areas.
This depicting likely stems from the nose of the LLJ being forecast
to right over the general vicinity, a synoptic representation that
typically denotes a greater likelihood of where the heavier precip
could occur. It will be something to monitor in the next
succession of CAMs output, but with such a solid signal, was
inclined to mention as a higher end SLGT will be forecast within
that Eastern NE through Western IA region.

Further north, a complex of storms will originate over Southern SD
from another shortwave progression moving through the Northern
Plains. This area could see the benefit of cell mergers somewhere
in the proxy of Southeast SD into Southwest MN as depicted within
multiple deterministic. Considering this area levying higher FFG's
compared to areas further south, the threat for significant flash
flooding is lower, but still generally within the SLGT risk
threshold considering the airmass in place. The SLGT risk is
positioned as far back as Northeast CO into Southern NE and as far
east as Northern IL and Southern WI thanks to multiple periods of
heavy convection impacting the region.

Kleebauer


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

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
408 AM EDT Tue Jun 24 2025
Day 2
Valid 12Z Wed Jun 25 2025 - 12Z Thu Jun 26 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
NEW MEXICO, CENTRAL PLAINS AND MIDWEST...

...New Mexico...

Despite a smaller areal coverage anticipated for convection across
New Mexico for Wednesday, scattered thunderstorms will still
cause problems during afternoon initiation as ample heating during
the prime destabilization window (16-21z) will yield another
threat of heavy rainfall across the terrain and adjacent valleys in
Central and Southern NM. Current signals are nowhere near as
robust as the D1 time frame, but with forecasted significant
impacts the period prior, there's a greater threat of truly
compromised FFG's leading in, allowing for the bar to be very low
for flash flooding over areas that will see significant rainfall in
the areas referenced above. Hi-res ensemble blended mean QPF is now
solidly within the 1-2" range with locally higher totals across the
Sacramento's. Areal average 0.5-1" of rainfall is forecast over
much of South-Central NM and over the Sangre de Cristos with totals
potentially up to 2" in stronger convective cores. The overlap with
the previous period allows for at least a SLGT risk with a higher
end SLGT progged over the Sacramento's where convective initiation
is likely. A targeted upgrade is plausible within the two main
mountain areas in the state, especially when you factor in the
antecedent conditions for the period in question. If CAMs come in
more robust, or impacts during the D1 are severe enough to fully
compromise soils to where any convective threat could be deemed
significant.

...Central Plains to Midwest...

Convective pattern across the Plains and Midwest at the end of the
D1 will translate northward into the Upper Mississippi Valley with
organized convection over NE/IA and SD/MN converging along the
propagating warm front leading to a swath of heavy rainfall across
much of the Southern 1/3rd of MN. All guidance is in agreement on a
pretty significant QPF shield moving through the area encompassing
Southern MN up through Northwest WI with some back-building
potential along the front as it migrates north and begins to slow
its momentum. Areal average of 1-2" with locally up to 4" totals
are forecast across that portion of the Upper Midwest, reflected
well within the NBM 90th percentile QPF signature, as well as
within the 12-00z time frame covered by the end of the 00z HREF
blended mean. This is just round 1 of what will be yet another
secondary convective initiation come Wednesday evening when another
strong shortwave and attendant IVT pulse comes pushing back over
Eastern NE, Western IA and points north. Additional heavy rainfall
will intersect many areas that will have seen significant totals
earlier in the period and the second half of the D1. The
compounding impacts will lead to scattered to widespread flash
flood instances as FFG's will be notably lower comparatively to
the before the previous rounds. Ensemble bias corrected mean is now
between 3-4" over a large area encompassing Southern MN into
Northwest WI with 2-3" positioned just to the southwest of MN. EC
AIFS output is in agreement with the positioning of the QPF maxima
anticipated, something that has not been the case over the past few
days, so we seem to be moving into a greater consensus. As a
result, there is a large high-end SLGT risk positioned from
Northeast NE up through MN into the western portion of WI. An
upgrade within anywhere in that zone is plausible in the coming
updates as multi-day impacts could spur some locally significant
flash flood prospects.

Kleebauer


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

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
408 AM EDT Tue Jun 24 2025
Day 3
Valid 12Z Thu Jun 26 2025 - 12Z Fri Jun 27 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE MIDWEST AND NORTHERN GREAT LAKES...

...Midwest...

The final shortwave in the progression bleeding over from the
previous D2 time frame will continue pushing northeast before
finally vacating the Upper Midwest later on Thursday. Heavy rain
threat will continue over parts of MN and WI before eventually
impacting the Western U.P. of Michigan before its departure.
Instability across the region will be significantly lower than
previous days with the warm front becoming stationary prior to
reaching the southern shores of Lake Superior. The threat for flash
flooding is most notably in the first 6-12 hr window of the
forecast with a sharp decline in the threat afterwards as the
pattern shifts with the ridge expected to be breaking down. 1-2"
with locally higher amounts will allow for flash flooding in any
area from IA up through MN/WI, especially in places where
significant rainfall has occurred in prior periods. A broad SLGT
risk remains in place over the Northern Great Lakes and Upper
Midwest with the biggest change being the extension down through
Central IA as trailing thunderstorms are forecast within the
frontal orientation Thursday afternoon and evening.

...New Mexico...

Isolated to scattered thunderstorms across the Sacramento's and
adjacent desert will maintain at least some threat for flash
flooding given expected wet antecedent conditions following
previous multi-day convective impact. Coverage and magnitude will
be lower than previous periods, but still enough of a threat and
coverage to warrant a MRGL continuation.

...Mid Atlantic...

Disturbance rounding the northern periphery of our massive ridge
will ultimately slide down through the Mid Atlantic during the
mid to late-afternoon hrs. on Thursday. The combination of strong
diurnal destabilization during the daytime and prominent moisture
lingering over the area will create a very buoyant environment
capable of strong thunderstorm genesis anywhere from NY state down
through the Central Mid Atlantic including; MD/PA/DE/Northern WV
and VA. Current projection of QPF is fairly isolated in the heavier
convective outputs with some deterministic depicting totals as
high as 2-3" in spots. Initial assessment of the setup leads
towards a low end MRGL risk for now, but will assess how models
handle the shortwave disturbance and proposed ascent pattern within
a fairly unstable environment over the next few days.

Kleebauer

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

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
303 AM EDT Tue Jun 24 2025


Moisture advection around the southeastern U.S. upper ridge
combined with shortwaves aloft and a wavy frontal boundary will
provide a favorable environment for convection for portions of the
northern tier into late week. An initial wave moving across the
Lower Great Lakes and Northeast Friday-Saturday will allow for some
possibly heavy rain in the Interior Northeast on the cusp of the
instability gradient and where a weak surface low tracks along the
front. Have Marginal Risks delineated in the Day 4/Friday and Day
5/Saturday EROs for localized flash flooding with this activity.
Farther south, showers and thunderstorms will become scattered to
widespread through much of the period across the eastern third of
the lower 48, mostly diurnally driven in the warm and unstable
airmass. There looks to be some thunderstorm focus stretching
across the central Appalachians especially Friday, so will
encompass that area within the Marginal Risk Day 4 ERO as well.
Will continue to monitor any other areas that show enhanced rain
totals that could trigger flash flood concerns. The central Gulf
Coast may see a few days of more focused convection, with heavier
amounts possible early next week (after the ERO period, and would
have to battle against high flash flood guidance to see flooding
concerns there).

Another shallow upper trough and frontal system will push through
the north-central U.S. late week into the weekend, providing
forcing for thunderstorms. Instability is likely to be high (MUCAPE
of 3000-5000 J/kg already shown by the global models...even higher
farther south, but where there is a drier atmosphere that could be
capped). Have Marginal Risks delineated in parts of the Dakotas
into the Upper Midwest on Friday and Saturday since locally heavy
rain rates are likely in this unstable atmosphere. Convection is
forecast to shift southeast across the Midwest and central
Plains/Middle Mississippi Valley early next week ahead of the
trough and front.

After a very wet short range period, support for heavy rain in New
Mexico will be waning by late week. However, any showers and
thunderstorms that form could be problematic for sensitive areas
like burn scars and terrain, especially considering the wet
antecedent conditions by then. Thus show a Marginal Risk for the
Sacramento Mountains and vicinity into Friday for isolated flash
flooding. Rain will continue to decrease in coverage and amounts on
Saturday. But into early next week, monsoonal moisture looks to
increase, bringing rain and thunderstorm chances to the southern
and central Rockies and High Plains.

The strong upper high/ridge stretching across the south-central to
eastern U.S. will be weaker by late week but remain generally in
place, maintaining hot temperatures albeit slightly moderated from
the short range period and less likely to break records.
Nevertheless, temperatures will be well into the 90s in many
central and eastern areas, while dewpoints in the 70s will raise
heat indices into the 100s. Overnight lows will only drop into the
low/mid 70s for many areas, bringing little relief from the heat
and exacerbating potential impacts. Especially after the extreme
heat in the short range, through late week HeatRisk values will be
Extreme for portions of the Ohio Valley, and Major from the Mid-
South into the southern Mid-Atlantic -- levels 3 and 4 on a scale
from 1 to 4 (4 being Extreme). This indicates an intensity and
duration of heat that is extremely dangerous to anyone without
adequate cooling or hydration. Extreme heat is the number 1
weather-related killer -- please take precautions if you are
outside during the hottest part of the day and seek cooling if you
are without adequate means. Into the weekend and early next week,
temperatures should slowly moderate in the east-central U.S. in
particular for closer to normal summer heat. Areas like the Mid-
Atlantic are expected to stay hot most days with generally Major
HeatRisk. Meanwhile the Northeast should see relief from the heat
by the medium range period behind a backdoor front, but could
gradually warm early next week. The north-central U.S. can expect
warmer than average temperatures by 5 to 10 degrees around Friday-
Saturday and then cool behind a cold front. Temperatures in the
Northwest will warm by early next week under an upper ridge. The
Desert Southwest can expect typical summer heat with temperatures
in the 100s and 110s.


Tate

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
303 AM EDT Tue Jun 24 2025


Moisture advection around the southeastern U.S. upper ridge
combined with shortwaves aloft and a wavy frontal boundary will
provide a favorable environment for convection for portions of the
northern tier into late week. An initial wave moving across the
Lower Great Lakes and Northeast Friday-Saturday will allow for some
possibly heavy rain in the Interior Northeast on the cusp of the
instability gradient and where a weak surface low tracks along the
front. Have Marginal Risks delineated in the Day 4/Friday and Day
5/Saturday EROs for localized flash flooding with this activity.
Farther south, showers and thunderstorms will become scattered to
widespread through much of the period across the eastern third of
the lower 48, mostly diurnally driven in the warm and unstable
airmass. There looks to be some thunderstorm focus stretching
across the central Appalachians especially Friday, so will
encompass that area within the Marginal Risk Day 4 ERO as well.
Will continue to monitor any other areas that show enhanced rain
totals that could trigger flash flood concerns. The central Gulf
Coast may see a few days of more focused convection, with heavier
amounts possible early next week (after the ERO period, and would
have to battle against high flash flood guidance to see flooding
concerns there).

Another shallow upper trough and frontal system will push through
the north-central U.S. late week into the weekend, providing
forcing for thunderstorms. Instability is likely to be high (MUCAPE
of 3000-5000 J/kg already shown by the global models...even higher
farther south, but where there is a drier atmosphere that could be
capped). Have Marginal Risks delineated in parts of the Dakotas
into the Upper Midwest on Friday and Saturday since locally heavy
rain rates are likely in this unstable atmosphere. Convection is
forecast to shift southeast across the Midwest and central
Plains/Middle Mississippi Valley early next week ahead of the
trough and front.

After a very wet short range period, support for heavy rain in New
Mexico will be waning by late week. However, any showers and
thunderstorms that form could be problematic for sensitive areas
like burn scars and terrain, especially considering the wet
antecedent conditions by then. Thus show a Marginal Risk for the
Sacramento Mountains and vicinity into Friday for isolated flash
flooding. Rain will continue to decrease in coverage and amounts on
Saturday. But into early next week, monsoonal moisture looks to
increase, bringing rain and thunderstorm chances to the southern
and central Rockies and High Plains.

The strong upper high/ridge stretching across the south-central to
eastern U.S. will be weaker by late week but remain generally in
place, maintaining hot temperatures albeit slightly moderated from
the short range period and less likely to break records.
Nevertheless, temperatures will be well into the 90s in many
central and eastern areas, while dewpoints in the 70s will raise
heat indices into the 100s. Overnight lows will only drop into the
low/mid 70s for many areas, bringing little relief from the heat
and exacerbating potential impacts. Especially after the extreme
heat in the short range, through late week HeatRisk values will be
Extreme for portions of the Ohio Valley, and Major from the Mid-
South into the southern Mid-Atlantic -- levels 3 and 4 on a scale
from 1 to 4 (4 being Extreme). This indicates an intensity and
duration of heat that is extremely dangerous to anyone without
adequate cooling or hydration. Extreme heat is the number 1
weather-related killer -- please take precautions if you are
outside during the hottest part of the day and seek cooling if you
are without adequate means. Into the weekend and early next week,
temperatures should slowly moderate in the east-central U.S. in
particular for closer to normal summer heat. Areas like the Mid-
Atlantic are expected to stay hot most days with generally Major
HeatRisk. Meanwhile the Northeast should see relief from the heat
by the medium range period behind a backdoor front, but could
gradually warm early next week. The north-central U.S. can expect
warmer than average temperatures by 5 to 10 degrees around Friday-
Saturday and then cool behind a cold front. Temperatures in the
Northwest will warm by early next week under an upper ridge. The
Desert Southwest can expect typical summer heat with temperatures
in the 100s and 110s.


Tate

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
303 AM EDT Tue Jun 24 2025

Valid 12Z Fri Jun 27 2025 - 12Z Tue Jul 01 2025

...Record heat is less likely by late week, but dangerous heat
continues for the Ohio Valley, Mid-South, and
Mid-Atlantic/Carolinas...

...Overview...

Into late week, the peak of the significant and extremely
dangerous heat wave will have waned. However, temperatures will
remain quite hot across the Ohio Valley back toward the Mid-South
and east toward the Mid-Atlantic and Carolinas as some weaker upper
ridging persists. The long duration of the heat wave will cause
exacerbated impacts, maintaining Major to Extreme HeatRisk in some
of these areas into late week and the weekend. Meanwhile, moisture
will advect north and then east around the broad southeastern U.S.
ridge in a "ring of fire" setup. Better chances for flash flooding
are now into the short range period, but a wavy frontal boundary
interacting with the remaining above average moisture could allow
for localized heavy rain and flash flooding across the central
Appalachians to Northeast Friday-Saturday. Additional rounds of
scattered thunderstorms are possible across much of the central and
eastern U.S. into the weekend and early next week, some of which
could have low-end heavy rain and flooding potential.


...Guidance/Predictability Assessment...

Model guidance continues to be agreeable in showing mean ridging
across the southeastern U.S. late week (though weaker compared the
near term) and expanding west over the weekend and early next week.
This creates a more zonal pattern across the country with the jet
stream staying in the northern tier. This puts much more emphasis
on the speed, depth, and evolution of individual shortwaves, which
can be more difficult to nail down at extended time ranges. The
first shortwave and weak surface low atop the Great Lakes seems to
show reasonable consensus but any seemingly minor waffling of the
features would lead to sensible weather differences, like the bulk
of QPF moving across the northern U.S. or southern Canada. Then the
next broader, but still shallow, trough should be coming across
the Northwest Friday and reach the north-central U.S. by Sunday.
For this feature, the main outlier was the 18Z GFS, which was
slower to bring the trough east while western Canadian energy gets
involved. The other operational models, including the 12Z GFS and
the new 00Z GFS, were more agreeable. Various AI/ML models show
some spread though, so adjustments may need to be made in the
future. The flow pattern may amplify a bit into next week as that
trough shows a little digging. Meanwhile ridging is forecast to
build with its axis along the Rockies or so, while a southern
stream trough gradually approaches California while a northeastern
Pacific upper low may send (uncertain) shortwaves toward the
Northwest.

The WPC forecast was initially based on a composite blend of the
12Z deterministic guidance. By Day 5-7, introduced and gradually
increased the proportion of the EC and GEFS ensemble means to
around half to lessen the influence of individual model
variability.


...Weather/Hazards Highlights...

Moisture advection around the southeastern U.S. upper ridge
combined with shortwaves aloft and a wavy frontal boundary will
provide a favorable environment for convection for portions of the
northern tier into late week. An initial wave moving across the
Lower Great Lakes and Northeast Friday-Saturday will allow for some
possibly heavy rain in the Interior Northeast on the cusp of the
instability gradient and where a weak surface low tracks along the
front. Have Marginal Risks delineated in the Day 4/Friday and Day
5/Saturday EROs for localized flash flooding with this activity.
Farther south, showers and thunderstorms will become scattered to
widespread through much of the period across the eastern third of
the lower 48, mostly diurnally driven in the warm and unstable
airmass. There looks to be some thunderstorm focus stretching
across the central Appalachians especially Friday, so will
encompass that area within the Marginal Risk Day 4 ERO as well.
Will continue to monitor any other areas that show enhanced rain
totals that could trigger flash flood concerns. The central Gulf
Coast may see a few days of more focused convection, with heavier
amounts possible early next week (after the ERO period, and would
have to battle against high flash flood guidance to see flooding
concerns there).

Another shallow upper trough and frontal system will push through
the north-central U.S. late week into the weekend, providing
forcing for thunderstorms. Instability is likely to be high (MUCAPE
of 3000-5000 J/kg already shown by the global models...even higher
farther south, but where there is a drier atmosphere that could be
capped). Have Marginal Risks delineated in parts of the Dakotas
into the Upper Midwest on Friday and Saturday since locally heavy
rain rates are likely in this unstable atmosphere. Convection is
forecast to shift southeast across the Midwest and central
Plains/Middle Mississippi Valley early next week ahead of the
trough and front.

After a very wet short range period, support for heavy rain in New
Mexico will be waning by late week. However, any showers and
thunderstorms that form could be problematic for sensitive areas
like burn scars and terrain, especially considering the wet
antecedent conditions by then. Thus show a Marginal Risk for the
Sacramento Mountains and vicinity into Friday for isolated flash
flooding. Rain will continue to decrease in coverage and amounts on
Saturday. But into early next week, monsoonal moisture looks to
increase, bringing rain and thunderstorm chances to the southern
and central Rockies and High Plains.

The strong upper high/ridge stretching across the south-central to
eastern U.S. will be weaker by late week but remain generally in
place, maintaining hot temperatures albeit slightly moderated from
the short range period and less likely to break records.
Nevertheless, temperatures will be well into the 90s in many
central and eastern areas, while dewpoints in the 70s will raise
heat indices into the 100s. Overnight lows will only drop into the
low/mid 70s for many areas, bringing little relief from the heat
and exacerbating potential impacts. Especially after the extreme
heat in the short range, through late week HeatRisk values will be
Extreme for portions of the Ohio Valley, and Major from the Mid-
South into the southern Mid-Atlantic -- levels 3 and 4 on a scale
from 1 to 4 (4 being Extreme). This indicates an intensity and
duration of heat that is extremely dangerous to anyone without
adequate cooling or hydration. Extreme heat is the number 1
weather-related killer -- please take precautions if you are
outside during the hottest part of the day and seek cooling if you
are without adequate means. Into the weekend and early next week,
temperatures should slowly moderate in the east-central U.S. in
particular for closer to normal summer heat. Areas like the Mid-
Atlantic are expected to stay hot most days with generally Major
HeatRisk. Meanwhile the Northeast should see relief from the heat
by the medium range period behind a backdoor front, but could
gradually warm early next week. The north-central U.S. can expect
warmer than average temperatures by 5 to 10 degrees around Friday-
Saturday and then cool behind a cold front. Temperatures in the
Northwest will warm by early next week under an upper ridge. The
Desert Southwest can expect typical summer heat with temperatures
in the 100s and 110s.


Tate


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