WW 622 SEVERE TSTM AL FL LA MS CW 241735Z - 250000Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 622
NWS Storm Prediction Center Norman OK
1235 PM CDT Mon Aug 24 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Southwest and Southern Alabama
Western Florida Panhandle
Southeast Louisiana
Southeast Mississippi
Coastal Waters
* Effective this Monday afternoon and evening from 1235 PM until
700 PM CDT.
* Primary threats include...
Scattered damaging wind gusts to 65 mph possible
SUMMARY...Small clusters of strong to severe thunderstorms will
continue to develop and intensify this afternoon across the Watch
area and gradually move towards the coast. The stronger
thunderstorms will pose a risk for wet microbursts capable of 55 to
65 mph gusts and scattered wind damage.
The severe thunderstorm watch area is approximately along and 60
statute miles north and south of a line from 25 miles west northwest
of New Orleans LA to 35 miles north northeast of Crestview FL. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU2).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for 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. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
AVIATION...A few severe thunderstorms with hail surface and aloft to
0.5 inches. Extreme turbulence and surface wind gusts to 55 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
34015.
...Smith
WW 0622 Status Updates
STATUS REPORT ON WW 622
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 NW MSY TO
20 NW GPT TO 20 NW MOB TO 50 E PIB.
..MEAD..08/24/26
ATTN...WFO...MOB...LIX...
STATUS REPORT FOR WS 622
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
ALC003-013-023-025-035-039-041-053-097-099-129-242140-
AL
. ALABAMA COUNTIES INCLUDED ARE
BALDWIN BUTLER CHOCTAW
CLARKE CONECUH COVINGTON
CRENSHAW ESCAMBIA MOBILE
MONROE WASHINGTON
FLC033-091-113-242140-
FL
. FLORIDA COUNTIES INCLUDED ARE
ESCAMBIA OKALOOSA SANTA ROSA
LAC051-057-063-071-075-087-089-095-103-242140-
LA
. LOUISIANA PARISHES INCLUDED ARE
JEFFERSON LAFOURCHE LIVINGSTON
MD 2118 CONCERNING SEVERE THUNDERSTORM WATCH 622... FOR SOUTHEAST LOUISIANA...FAR SOUTHEAST MISSISSIPPI...SOUTHWEST ALABAMA...AND THE WESTERN FLORIDA PANHANDLE
Mesoscale Discussion 2118
NWS Storm Prediction Center Norman OK
0257 PM CDT Mon Aug 24 2026
Areas affected...southeast Louisiana...far southeast
Mississippi...southwest Alabama...and the western Florida Panhandle
Concerning...Severe Thunderstorm Watch 622...
Valid 241957Z - 242200Z
The severe weather threat for Severe Thunderstorm Watch 622
continues.
SUMMARY...The threat for damaging winds continues, especially in
southeast Louisiana where an organized cold pool has developed.
DISCUSSION...As of 1955Z, mosaic radar imagery showed a broken band
of strong to severe storms from near Mobile west along the MS coast
through New Orleans to south of Baton Rouge. The western segment of
the thunderstorm band from St. John the Baptist to Ascension and St.
James Parishes has developed an organized cold pool with updrafts
exhibiting some forward-propagational characteristics, suggestive of
an enhanced damaging wind threat. There, severe gusts up to 65 mph
appear possible as that segment of storms continues south toward the
coast. Elsewhere, expect the damaging wind threat to be more
sporadic in nature through mid to late afternoon.
..Mead.. 08/24/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MOB...LIX...LCH...
LAT...LON 29929119 30529154 30879072 30748944 31058880 31698813
31668706 31698650 31118643 30518652 30138711 30068837
29568870 29068891 28918937 29028982 29139087 29929119
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MD 2117 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTH-CENTRAL SOUTH DAKOTA INTO WESTERN NEBRASKA
Mesoscale Discussion 2117
NWS Storm Prediction Center Norman OK
0240 PM CDT Mon Aug 24 2026
Areas affected...south-central South Dakota into western Nebraska
Concerning...Severe potential...Watch possible
Valid 241940Z - 242215Z
Probability of Watch Issuance...60 percent
SUMMARY...The threat for at least isolated severe storms capable of
severe wind gusts up to 65-80 mph and large hail potentially up to
two inches is expected to increase late this afternoon through this
evening. A watch is possible.
DISCUSSION...Visible satellite imagery shows a growing cumulus field
from Ogallala north toward Merriman in western NE, in the vicinity
of a surface trough. Additional, more elevated convection is noted
along the SD-NE border, near Pine Ridge. The 18Z North Platte
sounding sampled the presence of an EML with considerable capping
for surface-based parcels. Since that observation, surface
temperatures have warmed through the 80s into lower 90s, effectively
reducing the amount of convective inhibition.
Forcing for ascent associated with a subtle short-wave trough
currently moving through eastern WY in conjunction with continued
daytime heating is expected locally erode the cap such that isolated
thunderstorm development will become increasingly likely within the
next 1-3 hours along the surface trough and/or cool front moving
into the region from the north. The presence of steep low/mid-level
lapse rates and a vertically veering wind profile with 30-35 kt of
deep-layer shear will support organized storm modes, including
supercells with an associated risk for large hail, potentially up to
two inches and locally severe wind gusts. Latest time-lagged HRRR
and RRFS guidance suggests that a more robust damaging wind threat
could materialize this evening as storms merge into clusters, at
which point gusts up to 65-80 mph would become more likely.
..Mead/Smith.. 08/24/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ABR...LBF...UNR...BOU...
LAT...LON 41610258 42400258 43400219 43890190 44090135 43870057
43430010 42790004 41860009 41120027 40630054 40450114
40450159 40860215 41610258
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
MD 2116 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR FAR SOUTHEAST WYOMING INTO THE COLORADO FRONT RANGE AND FAR NORTHERN NEW MEXICO
Mesoscale Discussion 2116
NWS Storm Prediction Center Norman OK
0236 PM CDT Mon Aug 24 2026
Areas affected...Far southeast Wyoming into the Colorado Front Range
and far northern New Mexico
Concerning...Severe potential...Watch unlikely
Valid 241936Z - 242130Z
Probability of Watch Issuance...5 percent
SUMMARY...High-based thunderstorms moving off the higher terrain of
southeast Wyoming, central Colorado, and far north/northeast New
Mexico will pose a risk of severe winds through early evening. Watch
issuance is not expected given very limited buoyancy.
DISCUSSION...Visible satellite imagery shows steady cumulus
development along the CO Front Range within a weak upslope flow
regime as well as across southeast WY in proximity to a weak
low/mid-level MCV. Recent ACARs soundings from Denver, CO, along
with the KFTG VWP, sampled 15-20 knot westerly flow within the
CAPE-bearing layer that should promote eastward translation of
convection off of the higher terrain through late afternoon. These
soundings also sampled very dry boundary-layer conditions with LCLs
just under 3 km. Although the very dry low-level conditions are
limiting overall buoyancy magnitudes (SBCAPE is generally estimated
to be around 250-500 J/kg per mesoanalysis and representative
forecast soundings), they are highly favorable for intense
downbursts capable of producing swaths of severe winds. This idea is
reflected by a collection of recent CAM solutions, which generally
depict sporadic swaths of 60-75 mph gusts as convection slowly
intensifies and spreads east over the next few hours. The very
limited CAPE and modest kinematic environment should modulate
convective intensity and longevity (and preclude the need for a
watch), and convection should steadily weaken in tandem with
nocturnal cooling later this evening.
..Moore/Smith.. 08/24/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PUB...BOU...CYS...ABQ...
LAT...LON 37030490 38920488 40250551 40910551 41380531 41580487
41630430 41510394 41220368 40820364 39220349 36960379
36680391 36480418 36470457 36600481 37030490
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MD 2115 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF THE GREAT BASIN
Mesoscale Discussion 2115
NWS Storm Prediction Center Norman OK
0203 PM CDT Mon Aug 24 2026
Areas affected...Portions of the Great Basin
Concerning...Severe potential...Watch unlikely
Valid 241903Z - 242100Z
Probability of Watch Issuance...5 percent
SUMMARY...Isolated to widely-scattered thunderstorms are expected to
overspread much of the northern Great Basin through early evening.
The more intense thunderstorms will be capable of severe downburst
winds. However, the overall threat should remain transient/isolated
enough to preclude watch issuance.
DISCUSSION...Over the past hour, GOES imagery has shown a steady
uptick in coverage and depth of convective cumulus across the
central and northern Great Basin. This comes as temperatures warm
into the mid 80s to low 90s and lingering inhibition is eroded.
Based on recent surface observations and the recent 18z LKN
sounding, MLCAPE values generally between 250-500 J/kg are likely
overspreading much of the region, and low-level lapse rates are
approaching dry adiabatic with LCLs estimated to be near 2 to 2.5
km. Although buoyancy magnitudes are generally fairly modest, the
dry and deeply-mixed boundary layer is favorable for accelerating
downdrafts - especially with the deeper convective cores that can be
influenced by 30-35 knot mid-level flow above 6 km as sampled by the
LKN sounding (which may promote some degree of storm longevity and
organization). In general, thunderstorm coverage and longevity is
expected to remain fairly limited given weak large-scale forcing for
ascent, modest buoyancy, and somewhat weak deep-layer wind shear,
but latest CAM ensemble guidance suggests gusts up to 60-75 mph will
be possible with the more intense downbursts.
..Moore/Smith.. 08/24/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CYS...RIW...GJT...SLC...PIH...BOI...LKN...
LAT...LON 40630834 40500897 40381024 39741131 38961216 38821264
38911328 39281405 40141461 40521545 40701599 41111617
42651593 43031566 43351522 43511471 43681382 43930885
43890833 43650787 43030756 42150747 40990791 40630834
MOST PROBABLE PEAK WIND GUST...65-80 MPH
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1122 AM CDT Mon Aug 24 2026
Valid 241630Z - 251200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS/UPPER MIDWEST...CENTRAL HIGH PLAINS...LOWER
MISSISSIPPI VALLEY/CENTRAL GULF COAST...AND COASTAL CAROLINAS...
...SUMMARY...
Severe thunderstorms capable of producing large hail and severe wind
gusts will be possible this afternoon and evening across parts of
the Upper Midwest as well as the central High Plains. Other severe
thunderstorms with mainly a damaging wind threat are possible across
the central Gulf Coast and coastal Carolinas.
...Central Gulf Coast...
Satellite/radar mosaic late this morning shows a cluster of storms
moving south along the MS River. Mostly clear skies will promote
additional heating to the south over the coastal plain, which will
further destabilize the airmass and lead to steepening 0-2 km lapse
rates (in excess of 8 deg C/km) as temperatures warm into the lower
90s deg F. Deep-layer northerly steering flow will favor southward
movement of the thunderstorm cluster and new updraft development on
the leading edge of the cold pool. As this convection likely
continues to develop and become surface-based through the mid
afternoon, there will be a corresponding increase in potential for
scattered wet microbursts (55-65 mph gusts capable of wind damage)
with the stronger cores. This activity will likely push south of
the coast by the early evening.
...Dakotas/Upper Midwest into the Central High Plains...
A mid-level shortwave trough over Alberta/Saskatchewan will move
eastward across the Canadian prairie provinces through tonight, with
a belt of moderately strong flow aloft and multiple MCVs influencing
the northern Plains to Upper Midwest. Widely scattered
thunderstorms are forecast to develop late this afternoon into the
early evening within a moist/unstable airmass near an
eastward-moving front and weak surface wave across central/eastern
ND. Other convection may initiate and then move southeastward from
south-central Canada. Around 35-45 kt of deep-layer shear will
support supercells initially with a large hail threat. The
development of east/southeastward-moving clusters should eventually
occur this evening, with scattered severe gusts possible.
Farther south and a bit more removed from the stronger cyclonic flow
aloft, additional high-based thunderstorms are expected to form by
late afternoon/early evening across the Black Hills/western NE in
the vicinity of the surface front. Strengthening and sufficient
veering of winds with height through the mid levels should support
initial supercells capable of large hail, prior to a clustering of
these southeastward-moving thunderstorms. The risk for scattered
severe gusts may linger through mid/late evening across the central
High Plains before increasing MLCIN encourages gradual weakening.
...Coastal Carolinas...
A larger-scale low/troughing centered over the St. Lawrence Valley
will maintain cyclonic mid to high-level flow over the region this
afternoon. The 12 UTC Charleston, SC and Newport, NC raobs showed a
very unstable airmass in place to the southeast of a cold front
draped over the Carolinas. Veering and strengthening flow with
height will support deep-layer shear (30-35 kt) favorable for storm
organization. The stronger storms will be capable of a
hail/wind-damage risk this afternoon. See MCD #2112 for short-term
details through early afternoon regarding severe potential.
...Northern Great Basin into the Central Rockies...
Isolated to scattered high-based thunderstorms are expected to
develop this afternoon across parts of the northern Great Basin into
the central Rockies amid steepening low-level lapse rates with a
very well-mixed boundary layer. Since this convection will develop
along the periphery of stronger flow aloft, modest organization is
possible even though low-level moisture and related instability
should remain weak. Occasional dry microbursts may occur, some of
which could pose an isolated threat for severe gusts.
...Maine...
Partly cloudy skies will promote some heating and resulting in
weak instability (500-1000 J/kg MLCAPE) by early to mid afternoon.
Forecast soundings show elongated hodographs due to a 100+ kt upper
speed max overhead. A few of the stronger thunderstorms may be
capable of a localized hail/wind risk for a few hours before this
marginal threat subsides by early evening.
..Smith/Chalmers.. 08/24/2026
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Mon Aug 24 2026
Valid 242000Z - 251200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS/UPPER MIDWEST...EASTERN IDAHO...CENTRAL HIGH
PLAINS...LOWER MISSISSIPPI RIVER VALLEY/CENTRAL GULF COAST...AND
COASTAL CAROLINAS...
...SUMMARY...
Severe thunderstorms capable of producing large hail and severe wind
gusts will be possible this afternoon and evening across parts of
the Upper Midwest as well as the central High Plains. Other severe
thunderstorms with mainly a damaging wind threat are possible across
the central Gulf Coast, eastern Idaho, and coastal Carolinas.
...20z Update...
...Northern Great Basin...
A targeted upgrade to a Level 2/Slight risk was introduced for
portions of eastern Idaho where the latest HRRR/RRFS runs and TLE
probabilities suggest a corridor of locally greater damaging/severe
wind gust coverage may materialize in association with developing
convection across southern Idaho given a favorable thermodynamic
environment. Similarly, the 5% wind probability and CIG1 areas have
also been expanded across adjacent areas of the northern Great Basin
given the potential for high-based, loosely-organized convective
clusters to produce isolated damaging/severe wind gusts. See MCD
2115 for additional short-term details.
Elsewhere, the forecast remains generally on track with only minor
adjustments made to the existing outlook. See the discussion below
and MCDs 2116 and 2117 for additional short-term details.
..Chalmers/Moore.. 08/24/2026
.PREV DISCUSSION... /ISSUED 1122 AM CDT Mon Aug 24 2026/
...Central Gulf Coast...
Satellite/radar mosaic late this morning shows a cluster of storms
moving south along the MS River. Mostly clear skies will promote
additional heating to the south over the coastal plain, which will
further destabilize the airmass and lead to steepening 0-2 km lapse
rates (in excess of 8 deg C/km) as temperatures warm into the lower
90s deg F. Deep-layer northerly steering flow will favor southward
movement of the thunderstorm cluster and new updraft development on
the leading edge of the cold pool. As this convection likely
continues to develop and become surface-based through the mid
afternoon, there will be a corresponding increase in potential for
scattered wet microbursts (55-65 mph gusts capable of wind damage)
with the stronger cores. This activity will likely push south of
the coast by the early evening.
...Dakotas/Upper Midwest into the Central High Plains...
A mid-level shortwave trough over Alberta/Saskatchewan will move
eastward across the Canadian prairie provinces through tonight, with
a belt of moderately strong flow aloft and multiple MCVs influencing
the northern Plains to Upper Midwest. Widely scattered
thunderstorms are forecast to develop late this afternoon into the
early evening within a moist/unstable airmass near an
eastward-moving front and weak surface wave across central/eastern
ND. Other convection may initiate and then move southeastward from
south-central Canada. Around 35-45 kt of deep-layer shear will
support supercells initially with a large hail threat. The
development of east/southeastward-moving clusters should eventually
occur this evening, with scattered severe gusts possible.
Farther south and a bit more removed from the stronger cyclonic flow
aloft, additional high-based thunderstorms are expected to form by
late afternoon/early evening across the Black Hills/western NE in
the vicinity of the surface front. Strengthening and sufficient
veering of winds with height through the mid levels should support
initial supercells capable of large hail, prior to a clustering of
these southeastward-moving thunderstorms. The risk for scattered
severe gusts may linger through mid/late evening across the central
High Plains before increasing MLCIN encourages gradual weakening.
...Coastal Carolinas...
A larger-scale low/troughing centered over the St. Lawrence Valley
will maintain cyclonic mid to high-level flow over the region this
afternoon. The 12 UTC Charleston, SC and Newport, NC raobs showed a
very unstable airmass in place to the southeast of a cold front
draped over the Carolinas. Veering and strengthening flow with
height will support deep-layer shear (30-35 kt) favorable for storm
organization. The stronger storms will be capable of a
hail/wind-damage risk this afternoon. See MCD #2112 for short-term
details through early afternoon regarding severe potential.
...Northern Great Basin into the Central Rockies...
Isolated to scattered high-based thunderstorms are expected to
develop this afternoon across parts of the northern Great Basin into
the central Rockies amid steepening low-level lapse rates with a
very well-mixed boundary layer. Since this convection will develop
along the periphery of stronger flow aloft, modest organization is
possible even though low-level moisture and related instability
should remain weak. Occasional dry microbursts may occur, some of
which could pose an isolated threat for severe gusts.
...Maine...
Partly cloudy skies will promote some heating and resulting in
weak instability (500-1000 J/kg MLCAPE) by early to mid afternoon.
Forecast soundings show elongated hodographs due to a 100+ kt upper
speed max overhead. A few of the stronger thunderstorms may be
capable of a localized hail/wind risk for a few hours before this
marginal threat subsides by early evening.
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1209 PM CDT Mon Aug 24 2026
Valid 251200Z - 261200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL PLAINS...
...SUMMARY...
Scattered severe storms are likely over the central Plains tomorrow
(Tuesday), with more isolated severe storms possible over the Upper
Mississippi Valley and Gulf coastline. Over all areas, severe gusts
are the main threat, though a couple instances of hail or a tornado
are also possible over the Upper Mississippi Valley.
...Synopsis...
Upper ridging will dominate most of the CONUS as an upper trough
over the Northeast ejects into the Atlantic tomorrow (Tuesday).
Multiple embedded impulses are expected to pivot around the upper
ridge over the central U.S., encouraging surface troughing over the
Plains states. Low-level moisture advection beneath seasonably cool
temperatures aloft, along with modest forcing for ascent with the
surface trough, will encourage strong to severe thunderstorm
development across portions of the High Plains to the Upper MS
Valley.
...Portions of the central Plains...
Upslope flow of low-level moisture toward the higher
terrain/immediate lee of the Rockies will encourage thunderstorm
development tomorrow afternoon across the central High Plains. A
deep and relatively dry boundary layer will develop through the day,
with high-based pulse cellular and multicellular storms expected
(given relatively poor tropospheric vertical shear). Lapse rates
from the surface to 500 mb will reach the 8-9 C/km range, with
robust updrafts likely. These storms will quickly become outflow
dominant, leading to the cold-pool merger and the subsequent
organization of one or more loosely organized MCSs. Given steep
boundary layer lapse rates, efficient evaporative cooling will
promote the potential of severe gusts with the more organized storm
clusters, from far southern NE to the TX Panhandle.
...Parts of the Upper MS Valley...
By late afternoon, thunderstorms are poised to develop immediately
ahead of a surface trough as a 500 mb impulse and associated wind
maximum overspreads the Upper MS Valley. Surface dewpoints should
reach the low to mid 60s F, but will be overspread by modest
mid-level lapse rates (i.e. 6-7 C/km), yielding 2000-3000 J/kg
MLCAPE. Forecast hodographs are elongated, with some low-level
curvature noted. Supercells are expected to be the main storm mode,
accompanied by a sparse risk of all severe convective hazards.
...Eastern parts of the Gulf Coast...
Pulse cellular storms will develop along the Gulf Coast again
tomorrow, where mid 70s F surface dewpoints will yield enough
buoyancy to support strong thunderstorms. MLCAPE will likely exceed
2000 J/kg over several locales, with PWATS well over 2 inches
expected. As such, water-loaded downdrafts will promote wet
microbursts capable of producing wind damage.
..Squitieri.. 08/24/2026
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 PM CDT Mon Aug 24 2026
Valid 261200Z - 271200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
SOUTHERN AND CENTRAL HIGH PLAINS...GREAT LAKES INTO THE OHIO
VALLEY...AND PARTS OF THE LOWER MISSISSIPPI VALLEY...
...SUMMARY...
Isolated to widely scattered severe storms are expected across parts
of the central and southern High Plains, Great Lakes into the Ohio
Valley, and parts of the Lower Mississippi Valley. Damaging/severe
gusts are the main threat across these regions.
...Synopsis...
An upper ridge will stagnate over the western and central CONUS
through Wednesday, with an upper trough expected to progress over
eastern Canada, resulting in a broad northwesterly upper-air regime
with surface troughing over the MS Valley and Midwest. Seasonably
rich low-level moisture will overspread portions of the High Plains,
as well as the Great Lakes and portions of the Lower MS Valley,
aiding in the development of scattered strong to severe
thunderstorms.
...Central and Southern High Plains...
Another day of moist upslope low-level flow is expected across
portions of the central and southern High Plains, where orographic
lift will support convective initiation by mid afternoon. 60s F
surface dewpoints will advect northwestward beneath mid-level lapse
rates of at least 8 C/km, yielding 2000-3000 J/kg MLCAPE. Deep-layer
shear should remain rather modest, but given modestly elongated
hodographs, over 30 kts of effective bulk shear is likely in spots,
which will support at least transient supercells. Isolated instances
of severe wind and hail are the primary threats. If greater storm
coverage and/or shear becomes apparent, a Slight Risk upgrade may be
needed in future outlooks.
...Great Lakes into the OH Valley...
A wedge of 60s F surface dewpoints will advect north-northeast ahead
of the approaching surface trough, beneath 6-6.5 C/km mid-level
lapse rates, resulting in 1500-2500 J/kg MLCAPE. Thunderstorm
initiation should take place along/ahead of the surface trough as
surface temperatures rise into the mid 70s F by afternoon. Modest
veering and strengthening of the flow with height will encourage
over 35 kts of effective bulk shear, characterized by hodographs
with some curvature and elongation. Multicells, line segments, and
supercells are the expected storm mode, with severe wind/hail the
primary concerns. At the moment, expected limited storm coverage
precludes Slight risk probabilities.
...Lower MS Valley...
Thunderstorm development is expected Wednesday afternoon with the
heating of a very moist boundary layer, characterized by mid 70s F
surface dewpoints. Some organization into multicellular complexes is
possible given modest vertical speed shear as the region is grazed
by the aforementioned deep-layer northwesterly flow. MLCAPE will
likely reach 2000-3000 J/kg supporting wet downbursts with damaging
gust potential.
..Squitieri.. 08/24/2026
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1131 AM CDT Mon Aug 24 2026
Valid 241700Z - 251200Z
A passing mid-level wave will induce periods of locally elevated
fire weather conditions across portions of the Klamath River Basin
today. RH values may decline to less than 15% with wind gusts over
20 mph in terrain favored areas; however, spatial extent and
duration of these conditions will be limited, precluding the
introduction of highlights.
Based on the latest guidance and observations, only minor
adjustments were made to the Isolated Dry Thunderstorm risk area in
the northern Great Basin and Elevated highlights in the southern
Plains. Please see the previous discussion for more details.
..Elizalde-Garcia.. 08/24/2026
.PREV DISCUSSION... /ISSUED 0157 AM CDT Mon Aug 24 2026/
...Synopsis...
A subtle/low-amplitude midlevel wave will move northeastward across
parts of the northern Great Basin today. Farther south, a separate
shortwave trough will track southeastward across the
central/southern Plains -- along the northeastern periphery of an
expansive upper ridge centered on the southern Rockies. In response
to this feature, a surface low will evolve slowly eastward across
parts of OK.
...Dry Thunderstorms - Northern Great Basin...
Diurnal heating/boundary-layer mixing beneath a well-established
midlevel moisture plume will contribute to weak surface-based
destabilization across parts of the northern Great Basin today. As
large-scale forcing for ascent accompanying the midlevel wave
overspreads this instability, isolated high-based thunderstorms will
track northeastward across the area. The deeply mixed boundary layer
(inverted-V profiles) and 25-30 mph storm motions will favor dry
thunderstorms capable of lightning-induced ignitions -- given
receptive fuels.
...Southern Plains...
Along/behind the evolving surface low, a dry air mass (15-20 percent
RH) will develop amid 15-20 mph sustained west-southwesterly surface
winds. These dry/breezy conditions atop increasingly dry fuels
(95th+ percentile ERCs) will yield elevated fire-weather conditions
during the late morning and afternoon.
...Please see www.spc.noaa.gov/fire for graphic product...
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0246 PM CDT Mon Aug 24 2026
Valid 251200Z - 261200Z
Elevated fire weather highlights were introduced across the
wind-prone areas of LA/Ventura/Santa Barbara counties in southern
California for Day 2/Tuesday. The offshore gradient will be
strongest late evening through the overnight hours (perhaps into Day
3/Wednesday morning), with winds up to 15-25 mph (locally greater)
and 15-20% RH values promoting enhanced fire concerns as ERCs
approach the 90-95th percentile.
The rest of the forecast remains on track with only slight
adjustments made to the prior Isolated Dry Thunderstorm and Elevated
risk areas; please see the previous discussion for more information.
..Elizalde-Garcia.. 08/24/2026
.PREV DISCUSSION... /ISSUED 0159 AM CDT Mon Aug 24 2026/
...Synopsis...
Along the northwestern periphery of an expansive large-scale ridge
centered on the southern Rockies, a low-amplitude shortwave trough
will overspread the northern Great Basin into the northern Rockies.
Associated large-scale forcing for ascent and sufficient midlevel
moisture/instability will support isolated high-based thunderstorms
across parts of central/northern ID and southwestern MT during the
afternoon. Around 0.5-0.75 inch PW and 20-30 mph northeastward storm
motions will favor dry thunderstorms capable of producing
lightning-induced ignitions atop receptive fuels.
Additionally, enhanced deep-layer south-southwesterly flow
accompanying the midlevel trough will promote 15-20 mph sustained
southwesterly surface winds amid 15-20 percent RH across parts of
the northern Great Basin and vicinity during the afternoon. As a
result, elevated fire-weather conditions are expected, given very
dry fuels (90th-95th percentile ERCs).
...Please see www.spc.noaa.gov/fire for graphic product...
|
