WW 431 SEVERE TSTM AR KS MO OK 180230Z - 180900Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 431
NWS Storm Prediction Center Norman OK
930 PM CDT Tue Jun 17 2025
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Far Northwest Arkansas
South-Central into Southeast Kansas
Far Southwest Missouri
Central and Eastern Oklahoma
* Effective this Tuesday night and Wednesday morning from 930 PM
until 400 AM CDT.
* Primary threats include...
Widespread damaging winds and isolated significant gusts to 85
mph likely
Scattered large hail likely with isolated very large hail events
to 2 inches in diameter possible
A tornado or two possible
SUMMARY...A pair severe thunderstorm clusters are ongoing across OK,
one across west-central OK and the other across northeast OK. Both
of these clusters will continue to surge eastward over the next
several hours. Strong gusts to 80-85 mph are possible with these
storms. There is also a low-probability tornado risk with these
clusters. Additional thunderstorms are ongoing across south-central
KS. Large hail is currently the primary risk with these storms
although there is with some potential for linear development with
this activity as well. In general, the severe threat is expected to
move from west to east across the region tonight.
The severe thunderstorm watch area is approximately along and 80
statute miles east and west of a line from 20 miles north northeast
of Chanute KS to 35 miles southeast of Chickasha OK. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU1).
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.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 429...WW 430...
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 75 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
27035.
...Mosier
WW 0431 Status Updates
STATUS REPORT ON WW 431
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 SSW END
TO 5 NW MKO TO 5 S JLN TO 30 NNW JLN TO 50 NW SGF.
..KERR..06/18/25
ATTN...WFO...TSA...ICT...SGF...OUN...
STATUS REPORT FOR WS 431
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
ARC015-033-047-087-180840-
AR
. ARKANSAS COUNTIES INCLUDED ARE
CARROLL CRAWFORD FRANKLIN
MADISON
MOC009-011-039-057-097-109-217-180840-
MO
. MISSOURI COUNTIES INCLUDED ARE
BARRY BARTON CEDAR
DADE JASPER LAWRENCE
VERNON
OKC015-017-027-051-063-073-081-083-087-091-101-107-109-111-125-
133-135-180840-
OK
. OKLAHOMA COUNTIES INCLUDED ARE
MD 1342 CONCERNING SEVERE THUNDERSTORM WATCH 431... FOR PARTS OF EASTERN OKLAHOMA INTO SOUTHWESTERN MISSOURI AND NORTHWESTERN ARKANSAS
Mesoscale Discussion 1342
NWS Storm Prediction Center Norman OK
0114 AM CDT Wed Jun 18 2025
Areas affected...parts of eastern Oklahoma into southwestern
Missouri and northwestern Arkansas
Concerning...Severe Thunderstorm Watch 431...
Valid 180614Z - 180815Z
The severe weather threat for Severe Thunderstorm Watch 431
continues.
SUMMARY...The organized cluster of storms appears to be in the
process of weakening as it rapidly progresses eastward into the
Ozark Plateau. However, the potential for strong to severe surface
gusts may be slower to diminish, and trends are being monitored for
the possibility of an additional downstream severe weather watch.
DISCUSSION...At least one notable meso-beta scale cyclonic
circulation is being maintained, near/east of Bartlesville, OK.
Strong westerly rear inflow, in excess of 60 kts, to its south is
contributing to forward propagation of the main surface cold pool in
excess of 50 kt, within a westerly ambient mean flow regime on the
order of 25-30 kt. At this motion, activity could spread east of
the Branson MO/Harrison AR vicinities between 07-08Z.
2-hourly surface pressure change observations evident indicate that
a broad and significant surface pressure perturbation is being
maintained with the convective system. However, radar has indicated
substantive weakening of the more intense leading convective line
the last hour or so. It remains unclear if this may be due to a
potential stabilizing influence on easterly updraft inflow from a
smaller preceding cluster, or the gradual increase in inhibition
associated with boundary-layer cooling.
Based on current model output and observations, weakening convective
trends probably will continue through 08-09z, but strong to severe
surface gusts may be a bit slower to diminish with the residual
surface cold pool.
..Kerr.. 06/18/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LZK...SGF...TSA...
LAT...LON 36739448 36959429 36879306 36039271 35709330 35819452
35959447 36389444 36739448
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1228 AM CDT Wed Jun 18 2025
Valid 181200Z - 191200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST
MISSOURI INTO SOUTHERN LOWER MICHIGAN AND WESTERN OHIO...
...SUMMARY...
Strong to severe storms are expected today from parts of southern
Missouri northeastward into southern lower Michigan and western
Ohio. Damaging winds, isolated hail, and a few tornadoes will be
possible. More isolated severe storms may develop across the
southern Plains.
...Midwest/Southern Great Lakes...
A shortwave upper trough is forecast to move across the Mid-MS
Valley and Midwest today. A swath of enhanced deep-layer
southwesterly flow ahead of this feature will overspread portions of
the Ozarks to the Ohio Valley and southern Great Lakes ahead of a
surface front. A seasonally warm and moist airmass ahead of the
front/composite outflow will support moderate destabilization. A
surface low/MCV will develop northeast across central/northern IL to
southern Lower MI during the afternoon into early evening. The
current expectation is that thunderstorms will develop ahead of the
surface low and front, with a mix of clusters and line segments.
Midlevel lapse rates will remain modest, but isolated large hail is
possible. More likely, damaging gusts will be the main hazard as
linear convection develops ahead of the front. Tornado potential is
possible near the surface low from portions of northeast IL into
northern IN/southern Lower MI where low-level shear may be
maximized. However, forecast guidance varies considerable regarding
this scenario, so will maintain 5 percent tornado probabilities at
this time.
...TX/OK to the Mid-South...
A very moist and unstable airmass will be in place across the
region. A northeast to southwest oriented outflow boundary related
to an MCS that is currently ongoing across northern OK as of 06z
this morning will be draped across the Red River/southern OK
vicinity into the Ozarks. Isolated to scattered thunderstorms are
expected to develop diurnally. Large-scale ascent will be nebulous,
but supercell wind profiles and strong instability/steep lapse rates
will support isolated damaging wind and hail potential.
...Northern Plains...
Modest boundary layer moisture beneath steep midlevel lapse rates
will support weak diurnal destabilization. Increasing
west/northwesterly flow with height will provide sufficient shear
for some storm organization and elongated/straight hodographs are
indicated in forecast soundings. Furthermore, a deeply mixed
boundary layer is evident. This should support isolated hail and
strong gusts during the afternoon/early evening.
...Mid-Atlantic...
Strong heating of a very moist airmass will support moderate
destabilization. Deep-layer westerly flow will remain somewhat weak,
but sufficient for multicell clusters. Strong gusts may accompany
this activity.
..Leitman/Weinman.. 06/18/2025
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1254 AM CDT Wed Jun 18 2025
Valid 191200Z - 201200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF NEW
ENGLAND INTO THE MID ATLANTIC AND NORTH CAROLINA...
...SUMMARY...
Strong to potentially severe thunderstorms are forecast on Thursday
from parts of New England into the Mid Atlantic and Carolinas.
...Synopsis...
A seasonably deep mid/upper-level trough is forecast to move from
the lower Great Lakes region into the Northeast and Mid Atlantic on
Thursday. A surface low will move across parts of Quebec during the
day and evening, as a trailing cold front moves across parts of New
England, the Mid Atlantic, and Carolinas/Southeast.
An upstream midlevel shortwave trough will move across parts of
northern MN into WI and upper MI by evening. An amplified
mid/upper-level trough will move gradually eastward across the
western CONUS, as an upper-level ridge initially over the southern
Rockies begins to break down and shift eastward. In response to this
trough, a surface low will gradually deepen across the northern High
Plains.
...New England into the Mid Atlantic/Southeast...
Relatively rich low-level moisture will stream northward ahead of
the front approaching New England and the Mid Atlantic during the
day on Thursday. Moderate buoyancy may develop as far north as
northern NY/VT, with pockets of stronger heating/destabilization
farther south into the Mid Atlantic and Carolinas/Southeast.
The strongest deep-layer flow/shear is still expected from
PA/northern NJ northward into New England, where wind profiles will
be conditionally supportive of supercells and organized bowing
segments. Damaging winds and perhaps a tornado could accompany the
strongest storms in this area.
Farther south into the southern Mid Atlantic and Carolinas,
deep-layer flow will be somewhat unidirectional and weaker, but
still sufficient for some organized convection. Clusters capable of
producing scattered wind damage will be possible, especially in
areas where stronger diurnal heating/destabilization occurs.
Deep-layer flow will be rather weak into parts of MS/AL/GA/SC, but
the glancing influence of the mid/upper-level trough and relatively
large MLCAPE and PW will support storms capable of producing
isolated strong/damaging gusts.
...Southwest MT and vicinity...
Weak midlevel height falls are still expected across parts of
western MT Thursday afternoon/evening, in response to the
approaching mid/upper-level trough. Low-level moisture will remain
limited, but strong diurnal heating will support high-based storm
development. Steep low-level lapse rates and relatively strong
midlevel flow will result in potential for isolated severe gusts
during the afternoon and evening as convection spreads eastward.
...Upper Midwest...
Low-level warm advection related to the southeastward-moving
midlevel shortwave trough may aid in storm development on Thursday
from northern MN into parts of WI and upper MI. Moderate instability
and sufficient deep-layer shear will support potential for a few
stronger cells/clusters capable of producing large hail and damaging
wind. Additional strong to locally severe storms may redevelop later
Thursday night across parts of this region, in response to a
nocturnally strengthening low-level jet.
...Northern Plains...
Diurnal heating of an increasingly moist airmass will result in
moderate to strong buoyancy across parts of the northern Plains by
Thursday afternoon. Deep-layer shear will be sufficient for
organized storms, but diurnal storm development remains highly
uncertain amid background midlevel height rises associated with a
building ridge. Development of a storm or two cannot be ruled out
through evening near a surface trough/weak dryline. Elevated storm
coverage may increase somewhat Thursday night in response to a
strengthening low-level jet, which could pose a threat of hail and
localized strong gusts.
..Dean.. 06/18/2025
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 AM CDT Wed Jun 18 2025
Valid 201200Z - 211200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
NORTHERN PLAINS INTO THE UPPER MIDWEST/GREAT LAKES...
...SUMMARY...
Severe thunderstorms may develop Friday into Friday night across
parts of the northern Plains and upper Midwest.
...Synopsis...
An upper-level ridge is forecast to amplify on Friday from the
southern Plains into parts of the MS/OH Valleys, as a seasonably
deep mid/upper-level trough moves gradually eastward over the West.
Rich low-level moisture will continue to stream northward to the
east of a deepening lee surface cyclone across the northern High
Plains. Multiple shortwaves may emanate out of the western trough
and traverse the periphery of the building ridge from the northern
Rockies/Plains into the Upper Midwest and parts of Great Lakes.
...Northern Great Plains into the Upper Midwest/Great Lakes...
Uncertainty remains high regarding the details of convective
evolution Friday into Friday night, but potential for severe storm
development within a relatively volatile environment remains
evident.
To the east of the High Plains cyclone and trailing surface trough,
and along/south of an effective warm front, strong to extreme
buoyancy will develop Friday afternoon across parts of the
central/northern Plains into the Upper Midwest. Details of diurnal
storm development (if any) within this regime remain unclear.
Warming temperatures aloft may tend to suppress development across
the warm sector, but shortwaves emanating out of the western
mid/upper-level trough may aid in development of an isolated
supercell or two near the surface trough/dryline and/or effective
warm front. Any surface-based development within this regime could
pose a threat for all severe hazards.
A somewhat more likely scenario is for storms to expand in coverage
near/north of the warm front during the evening, in response to a
strengthening low-level jet and related warm-advection regime. Large
to extreme buoyancy and favorable deep-layer shear will support
organized convection, with upscale growth into a potentially intense
MCS possible with time. At this time, the most likely MCS corridor
appears to be somewhere from eastern ND into central/northern MN,
northern WI, and upper MI, though uncertainty remains high due to
varying guidance solutions regarding the location of the warm front
and evolution of the low-level jet.
Despite the remaining uncertainty, a Slight Risk has been added
given the conditional potential for significant severe weather. Some
adjustments to this area will likely be needed with time, along with
possible upgrades.
...Montana...
Low-level easterly flow will transport modest moisture into parts of
central/western MT during the day on Friday. Increasingly difluent
upper-level flow associated with the deep western trough will
support development of scattered to numerous thunderstorms through
the day into Friday night. Elongated hodographs will support
organized storms, with a threat of at least isolated hail and strong
to severe gusts with initial convection over western MT. One or more
clusters may move into central and northeast MT by evening, with a
continued threat of severe gusts and hail. Depending on trends
regarding destabilization, greater severe probabilities may
eventually be needed.
...Lower Great Lakes into the Northeast...
Modest low-level moistening is possible during the day on Friday
from the lower Great Lakes into the Northeast, within a developing
northwesterly flow regime in the wake of a departing mid/upper-level
trough. While wind profiles may become somewhat favorable for
organized convection, relatively cool post-frontal conditions and
generally weak midlevel lapse rates will tend to limit
destabilization, and any foci for robust storm development are not
clear at this time.
..Dean.. 06/18/2025
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0150 AM CDT Wed Jun 18 2025
Valid 181200Z - 191200Z
...Synopsis...
Within the base of a deep midlevel low off of British Columbia, a
shortwave trough and related midlevel westerly speed maximum will
overspread the Pacific Northwest. As a result, dry/breezy downslope
flow will develop in the Columbia Basin during the afternoon. Here,
around 15 mph sustained westerly surface winds (higher in the
Cascade Gaps) and 20-25 percent RH will favor elevated to locally
critical fire-weather conditions over dry fuels.
..Weinman.. 06/18/2025
...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
0150 AM CDT Wed Jun 18 2025
Valid 191200Z - 201200Z
...CRITICAL FIRE WEATHER AREA FOR NORTHWESTERN NEVADA...
...CRITICAL FIRE WEATHER AREA FOR PARTS OF EASTERN NEVADA...WESTERN
UTAH...AND FAR NORTHWESTERN ARIZONA...
...Synopsis...
Preceding a large-scale trough over the West Coast, moderate-strong
deep-layer southwesterly flow will overspread central CA into the
Great Basin through the afternoon. As this occurs, the surface
pressure gradient will tighten across much of the West -- peripheral
to surface lows evolving over the northern Great Basin and the Lower
CO River Valley.
...Great Basin...
Strong diurnal heating amid a dry antecedent air mass will result in
a deeply mixed boundary layer across much of the Great Basin --
characterized by widespread surface temperatures in the 90s to 100 F
and single-digit RH. At the same time, the deep boundary-layer
mixing into the strong flow aloft, coupled with a tightening
pressure gradient, will yield an expansive area of 25 mph sustained
southwesterly surface winds (with higher gusts). Over portions of
northwest NV and eastern NV/western UT, these hot, dry, and windy
conditions over receptive fuels will lead to critical fire-weather
conditions.
...San Joaquin Valley and adjacent areas...
The tightening pressure gradient and boundary-layer mixing into the
enhanced flow aloft will favor dry/breezy conditions in the San
Joaquin Valley and adjacent areas during the afternoon -- where
elevated fire-weather conditions are expected over any dry/receptive
fuels.
..Weinman.. 06/18/2025
...Please see www.spc.noaa.gov/fire for graphic product...
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