RSS Mesoscale Discussions from Storm Prediction Center
WW 564 TORNADO CO NE WY 012045Z - 020400Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 564
NWS Storm Prediction Center Norman OK
245 PM MDT Fri Aug 1 2025
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of
Northeast Colorado
Nebraska Panhandle
Southeast Wyoming
* Effective this Friday afternoon and evening from 245 PM until
1000 PM MDT.
* Primary threats include...
A couple tornadoes possible
Scattered large hail and isolated very large hail events to 3
inches in diameter possible
Scattered damaging wind gusts to 70 mph possible
SUMMARY...Thunderstorms are forecast to continue to develop and
intensify this afternoon and persist through the evening. The
stronger storms will likely become supercellular and pose a risk for
large to very large hail (1 to 3 inches in diameter). A couple of
tornadoes are also possible mainly towards the late afternoon and
early evening when the peak supercell phase is forecast. Upscale
growth into a thunderstorm cluster may subsequently occur this
evening and the risk for severe gusts may correspondingly increase.
The tornado watch area is approximately along and 75 statute miles
east and west of a line from 15 miles west northwest of Scottsbluff
NE to 30 miles west southwest of Akron CO. For a complete depiction
of the watch see the associated watch outline update (WOUS64 KWNS
WOU4).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.
&&
AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 3 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 28015.
...Smith
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WW 0564 Status Updates
STATUS FOR WATCH 0564 HAS NOT BEEN ISSUED YET
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MD 1863 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PARTS OF EASTERN WYOMING AND COLORADO INTO PARTS OF WESTERN NEBRASKA AND ADJACENT SOUTHWESTERN SOUTH DAKOTA
Mesoscale Discussion 1863
NWS Storm Prediction Center Norman OK
0251 PM CDT Fri Aug 01 2025
Areas affected...parts of eastern Wyoming and Colorado into parts of
western Nebraska and adjacent southwestern South Dakota
Concerning...Severe potential...Watch possible
Valid 011951Z - 012145Z
Probability of Watch Issuance...60 percent
SUMMARY...Scattered intensifying thunderstorm development, including
the evolution of a few supercells, appears probable through 3-5 PM
MDT. Trends are being monitored for the possibility of a severe
weather watch.
DISCUSSION...Downstream of an upper jet nosing inland of the central
California coast through the Great Basin, modest surface troughing
is slowly deepening to the lee of the Wyoming/Colorado Rockies.
Low-level moisture return on southerly flow to the east of the
trough axis is ongoing, and contributing to substantive
destabilization in the presence of steep lower/mid-tropospheric
lapse rates. This now appears to include moderately large CAPE in
excess of 2000 J/kg, where deep-layer shear (mostly due to
pronounced veering of winds with height, in the presence of
otherwise weak lower/mid-tropospheric flow) appears at least
marginally conducive to organized convection, including supercells.
High-based convection has been initiating and increasing in coverage
near and west of the Colorado Front Range through the Laramies the
past couple of hours. Gradually, as mid/upper support for this
activity shifts to the east of the higher terrain, scattered
thunderstorm activity will begin to develop east of the higher
terrain into the stronger potential instability across the adjacent
plains. As this occurs, substantive intensification appears
probable, including the evolution of a few supercells posing a risk
for large hail, locally damaging wind gusts, and perhaps a brief
tornado or two by 21-23Z.
..Kerr/Smith.. 08/01/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...UNR...GLD...BOU...CYS...
LAT...LON 43190420 42870349 41300299 39730202 38690302 38990361
39970331 40430431 40920475 41440499 42250485 42570510
43190420
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
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MD 1862 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL MISSISSIPPI AND WESTERN ALABAMA
Mesoscale Discussion 1862
NWS Storm Prediction Center Norman OK
0207 PM CDT Fri Aug 01 2025
Areas affected...Central Mississippi and western Alabama
Concerning...Severe potential...Watch unlikely
Valid 011907Z - 012100Z
Probability of Watch Issuance...5 percent
SUMMARY...Damaging winds are becoming increasingly possible across
central Mississippi and far western Alabama. However, the overall
magnitude of this threat should remain sufficiently limited to
preclude watch issuance.
DISCUSSION...Recent imagery from KGWX and KDGX shows convective
clusters developing across central MS as a diffuse cold front begins
to impinge on a moist and uncapped air mass. Recent RAP and HRRR
forecast soundings appear to be capturing near-surface
temperature/dewpoint trends well, and suggest MLCAPE values are
within the 2000-2500 J/kg range with theta-e deficits on the order
of 20-25 K, and 0-1 km lapse rates approaching 8 C/km. This
thermodynamic environment is favorable for strong wet downbursts,
which will become increasingly likely as cold pool
amalgamation/upscale growth continues with the gradual
intensification of the emerging thunderstorm cluster. Sporadic
damaging wind gusts (most likely within the 45-55 mph range) appear
likely, though a gust or two near 60 mph will be possible as this
activity spreads south/southeast through late afternoon. Very weak
flow aloft sampled by regional VWPs (generally 15 knots or less
through 7 km) will limit the potential for appreciable storm
organization and more substantial peak gusts, though isolated
instances wind damage are anticipated.
..Moore/Smith.. 08/01/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BMX...MOB...MEG...JAN...
LAT...LON 33309046 33698935 34058826 33908768 33628738 33148734
32588746 32238767 32038798 31918858 31918916 31978955
32048988 32189019 32379042 32629053 32859063 32999064
33309046
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Fri Aug 01 2025
Valid 011630Z - 021200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA...
...SUMMARY...
Scattered severe thunderstorms are possible across parts of the High
Plains this afternoon and evening. Large to very large hail, a
couple of tornadoes, and severe gusts are possible.
...High Plains...
Water-vapor imagery late this morning shows a few disturbances
undercutting an upper ridge currently over the High Plains/Alberta.
An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more
pronounced upper trough will remain over the northern Rockies and
adjacent high plains of MT, and a more subtle disturbance will move
east-northeastward across the central Rockies.
A residual frontal zone draped generally south-north abutting the
higher terrain is providing a focus for richer moisture east of this
boundary over the High Plains. Surface dewpoints will likely range
from the mid 50s to the lower 60s across much of the Slight Risk. A
belt of slightly stronger westerly upper flow is forecast across the
central High Plains which will act to elongate hodographs.
Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg
C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon.
The aforementioned low-amplitude disturbance over the central
Rockies coupled with low-level upslope flow/orographic effects will
result in initial thunderstorm development over the high terrain and
the Cheyenne Ridge.
The best overlap between buoyancy and shear is expected from western
SD into northeast CO/WY/NE Panhandle border region. Model ensemble
data suggest a few favored corridors for severe may result. The
most notable area may focus near the Cheyenne Ridge and adjacent
northeast CO where supercell potential appears greatest. Large to
very large hail and a tornado or two are possible with this activity
before gradually transitioning to primarily a risk for severe gusts.
One other area of interest is across northwest SD, where an MCV
moving slowly into the region could result in a focused area of
thunderstorms. Increased low-level convergence and low-level
vertical shear near this MCV could lead to a greater threat for all
severe hazards, including large hail and perhaps a brief tornado or
two.
...Carolinas into Georgia-Alabama-Mississippi...
A seasonably moist airmass was sampled by 12 UTC area raobs this
morning (near 16 g/kg lowest 100-mb mean mixing ratio).
Visible-satellite imagery shows extensive low cloud cover across
central and eastern NC near and behind the wind shift/cold front.
Farther west, initial cumulus field development is noted over the
southern Appalachians where strong heating is occurring and farther
south/southeast over the Piedmont and to the coastal plain. As
temperatures continue to warm through early afternoon, erosion of
convective inhibition will result in scattered storms favoring the
higher terrain and eventually near the wind shift. High PW (2
inches or greater) and diurnally steepened surface to 1.5 km lapse
rates will support a risk for wet microbursts with the more intense
water-loaded downdrafts. Localized gusts 50-65 mph are possible and
scattered pockets of wind damage may result.
..Smith/Moore.. 08/01/2025
Read more
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0253 PM CDT Fri Aug 01 2025
Valid 012000Z - 021200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT
RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS
INTO WESTERN SOUTH DAKOTA...
...SUMMARY...
Scattered severe thunderstorms are possible across parts of the High
Plains this afternoon and evening. Large to very large hail, a
couple of tornadoes, and severe gusts are possible.
...20z Update...
The forecast largely remains on track. The primary update was to
introduce 5% tornado probabilities across portions of northwest SD
ahead of a pronounced MCV where initial stages of thunderstorm
development are noted in recent GOES/lightning data. Visible imagery
shows slowly building cumulus within the southeasterly flow regime
ahead of the MCV as temperatures warm into the mid/upper 70s.
Forecast soundings suggest this is adequate for surface-based
convection, and depict enlarging hodographs later this evening as
the nocturnal jet strengthens. While localized, this environment may
be somewhat more favorable for tornadoes compared to adjacent
portions of SD.
Elsewhere, minimal changes are required. 5% wind probabilities were
amended slightly across portions of the Carolinas to better reflect
recent thunderstorm development/trends. See the previous discussion
below as well as MCDs #1860-1862 for additional details.
..Moore.. 08/01/2025
.PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/
...High Plains...
Water-vapor imagery late this morning shows a few disturbances
undercutting an upper ridge currently over the High Plains/Alberta.
An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more
pronounced upper trough will remain over the northern Rockies and
adjacent high plains of MT, and a more subtle disturbance will move
east-northeastward across the central Rockies.
A residual frontal zone draped generally south-north abutting the
higher terrain is providing a focus for richer moisture east of this
boundary over the High Plains. Surface dewpoints will likely range
from the mid 50s to the lower 60s across much of the Slight Risk. A
belt of slightly stronger westerly upper flow is forecast across the
central High Plains which will act to elongate hodographs.
Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg
C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon.
The aforementioned low-amplitude disturbance over the central
Rockies coupled with low-level upslope flow/orographic effects will
result in initial thunderstorm development over the high terrain and
the Cheyenne Ridge.
The best overlap between buoyancy and shear is expected from western
SD into northeast CO/WY/NE Panhandle border region. Model ensemble
data suggest a few favored corridors for severe may result. The
most notable area may focus near the Cheyenne Ridge and adjacent
northeast CO where supercell potential appears greatest. Large to
very large hail and a tornado or two are possible with this activity
before gradually transitioning to primarily a risk for severe gusts.
One other area of interest is across northwest SD, where an MCV
moving slowly into the region could result in a focused area of
thunderstorms. Increased low-level convergence and low-level
vertical shear near this MCV could lead to a greater threat for all
severe hazards, including large hail and perhaps a brief tornado or
two.
...Carolinas into Georgia-Alabama-Mississippi...
A seasonably moist airmass was sampled by 12 UTC area raobs this
morning (near 16 g/kg lowest 100-mb mean mixing ratio).
Visible-satellite imagery shows extensive low cloud cover across
central and eastern NC near and behind the wind shift/cold front.
Farther west, initial cumulus field development is noted over the
southern Appalachians where strong heating is occurring and farther
south/southeast over the Piedmont and to the coastal plain. As
temperatures continue to warm through early afternoon, erosion of
convective inhibition will result in scattered storms favoring the
higher terrain and eventually near the wind shift. High PW (2
inches or greater) and diurnally steepened surface to 1.5 km lapse
rates will support a risk for wet microbursts with the more intense
water-loaded downdrafts. Localized gusts 50-65 mph are possible and
scattered pockets of wind damage may result.
Read more
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1218 PM CDT Fri Aug 01 2025
Valid 021200Z - 031200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE
CENTRAL/SOUTHERN HIGH PLAINS...
...SUMMARY...
Isolated severe storms capable of large hail and severe wind gusts
are expected in parts of the central/southern High Plains on
Saturday. Additional strong storms are possible across parts of the
Southeast.
...Synopsis...
Ridging aloft will persist in the western/central CONUS on Saturday.
A few smaller shortwave perturbations may move through the zonal
flow aloft in the northern/central Rockies. Widely scattered to
scattered storms are possible within the higher terrain. This
activity will eventually move into the High Plains. A surface
boundary will be the focus for convection in the Southeast. Some of
this activity may be strong to locally severe.
...Central/southern High Plains...
A belt of stronger mid-level flow will develop across the central
Rockies through the day. A weak shortwave trough may also approach
the region from the Great Basin. With a weak lee trough and surface
southerly/southeasterly winds, effective shear of 40-45 kts would
support supercells, at least initially. Large temperature-dewpoint
spreads at the surface will likely result in outflow dominant storms
with quicker clustering/upscale growth. Very steep mid-level lapse
rates and long hodographs make large hail a possibility with these
initials cells. With time, cell interactions will likely produce a
few clusters that will move into the High Plains. A modest low-level
jet will develop during the evening in the southern High Plains.
This region appears to have a greater potential for sustaining
storms farther south and east for that reason. Severe wind gusts
will likely be the primary hazard from late afternoon into the
evening.
...Southeast...
Along the surface boundary, a weak frontal wave is possible near the
Alabama/Georgia border. This, in combination with heating along the
boundary, will support 2500-3000 J/kg MLCAPE by the afternoon. Given
the mid/upper 70s F dewpoints and high PWAT values, scattered storm
coverage could lead to isolated strong/damaging downburst winds.
Shear will be quite modest (around 20 kts of effective shear or
less) and the local severe risk will be dependent on storm
clustering.
..Wendt.. 08/01/2025
Read more
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0217 PM CDT Fri Aug 01 2025
Valid 031200Z - 041200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE HIGH PLAINS...
...SUMMARY...
Isolated to widely scattered thunderstorms are possible in the High
Plains during the afternoon Sunday. Some storms may produce large
hail and severe wind gusts.
...Synopsis...
Ridging aloft will continue in Southwest/Great Basin on Sunday. A
shortwave trough will move into the Northwest into the northern
Great Basin by late afternoon into the evening. An MCV evolving out
of High Plains convection on Saturday appears probable in the
southern Plains. Some mid-level flow enhancement will continue over
the central/southern Rockies.
...Southern High Plains into Northwest Texas...
Some convection may be ongoing early Sunday morning in association
with an MCV. There is some potential for this activity to
reintensify as surface heating increases. However, model guidance
has been uniform in dissipating this convection before that occurs.
To its west, the lee trough and an outflow boundary will potentially
promote convective development later in the afternoon. With the
Southwest ridge amplifying and the region being in the wake of the
earlier convection/MCV, there is still some uncertainty as to how
much convection will develop. The environment, however, will be
supportive of organized storms. 40-50 kts of northwesterly shear
would result in supercells. Large hail and severe gusts would be the
main threats, but augmented low-level shear along the outflow could
promote some tornado risk. Some upscale growth would be expected by
evening as a modest low-level jet develops in the Permian
Basin/South Plains. Higher probabilities may be needed if confidence
increases in storm development and coverage.
...Central into Northern High Plains...
With moisture remaining up against the terrain, additional strong to
severe storms are possible from eastern Colorado into eastern
Wyoming and the Black Hills. Aside from the terrain, the weak
surface trough will also serve as a focus for convective
development. Shear will generally be weaker in these areas, but
around 25-30 kts of effective shear could promote a few marginal
supercells and multicell clusters. Storms may not remain organized
for a long duration as upper-level flow is weak. The strongest
activity could produce large hail and severe wind gusts.
...Oregon...
With the approach of the trough, scattered storms are possible in
central Oregon in the Blue Mountains. Though buoyancy will be
limited, adequate effective shear could promote marginally organized
storms. Severe wind gusts would be the main hazard given inverted-v
profiles. Confidence in the coverage of strong to severe storms is
too low for highlights at this time.
..Wendt.. 08/01/2025
Read more
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1143 AM CDT Fri Aug 01 2025
Valid 011700Z - 021200Z
Hot, very dry (minimum RH values less than 10%), and breezy
(sustained surface winds of 15-20 mph) conditions are expected today
across much of the central/southern Great Basin and neighboring
portions of northwest Colorado and southwest Wyoming. As of 16Z,
observations across this area suggest locally elevated conditions
already ongoing with critical RH values present. Widespread elevated
conditions are expected from midday through this evening as winds
strengthen and RH values fall even further. The Elevated fire
weather area was expanded across this region based on the latest
high-resolution ensemble guidance.
Elevated fire weather conditions are also likely across wind-prone
portions of the Snake River Plain in Idaho, where several hours of
sustained winds of 15-20 mph (with greater gusts) and minimum RH
values near 15% are expected this afternoon/evening.
Locally critical fire weather conditions are most likely across
portions of southwest Utah, northwest Colorado into southwest
Wyoming, and also the Snake River Plain. Though, coverage is
forecast to be too spotty/brief to upgrade to Critical across these
areas.
The forecast for isolated dry thunderstorms over portions of the
northern Great Basin/Intermountain West remains on-track. Gusty and
erratic outflow winds will be possible nearby any thunderstorms.
Please see the previous discussion for more information on today's
fire weather forecast.
..Elliott.. 08/01/2025
.PREV DISCUSSION... /ISSUED 0155 AM CDT Fri Aug 01 2025/
...Synopsis...
Between a large-scale ridge centered on the Southwest/northern
Mexico and a broad/slow-moving midlevel trough crossing northern CA,
enhanced west-southwesterly midlevel flow will overspread the
southern Great Basin. Deep boundary-layer mixing into this enhanced
flow aloft will yield hot, dry, and breezy conditions during the
afternoon. Given receptive fuels, elevated fire-weather conditions
are expected across southern NV into southern UT.
Farther north, cool temperatures aloft/steep midlevel lapse rates
accompanying the trough will promote another day of isolated to
widely scattered high-based thunderstorms across the northern Great
Basin/Intermountain West. Inverted-V profiles and 0.6-0.7 inch PW
will favor mostly dry thunderstorms, with a risk of
lightning-induced ignitions over receptive fuels.
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0224 PM CDT Fri Aug 01 2025
Valid 021200Z - 031200Z
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN/SOUTHEASTERN
UTAH INTO NORTHWEST COLORADO...
Another day of hot, dry, and breezy conditions is likely tomorrow
(Saturday) afternoon/evening across much of the southern/eastern
Great Basin and adjacent portions of northern Arizona, western
Colorado, and southwestern Wyoming. A Critical fire weather area was
introduced across portions of southern/eastern Utah and northwestern
Colorado, where several hours of sustained winds in excess of 20 mph
and minimum RH values around 10-15% overlapping critically receptive
fuels are expected.
Minor modifications were also made to the isolated dry thunderstorm
area over portions of the northern Great Basin and Intermountain
West based on the latest high-resolution ensemble guidance.
Please see the previous discussion below for more information on
tomorrow's fire weather forecast.
..Elliott.. 08/01/2025
.PREV DISCUSSION... /ISSUED 0156 AM CDT Fri Aug 01 2025/
...Synopsis...
A midlevel shortwave trough will deamplify as it moves slowly
eastward across the northern Great Basin during the day. Large-scale
forcing for ascent and steep low/midlevel lapse rates preceding this
feature will promote another day of isolated to widely scattered
high-based thunderstorms across the northern Great
Basin/Intermountain West. Around 0.5-0.7 inch PW and modest storm
motions will support mostly dry thunderstorms, posing a risk of
lightning-induced ignitions over receptive fuels.
Between the shortwave trough and a large-scale ridge over the
Southwest/northern Mexico, moderate midlevel westerly flow will
overspread a deeply mixed boundary layer over parts of the
Southwest/Great Basin into the central Rockies. Single-digit to
lower teens RH and breezy west-southwesterly surface winds will
yield elevated to locally critical fire-weather conditions across
parts of northern AZ, much of southern/central UT, and far western
CO during the afternoon.
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
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