MD 1639 CONCERNING SEVERE THUNDERSTORM WATCH 491... FOR NORTHEAST NORTH DAKOTA
Mesoscale Discussion 1639
NWS Storm Prediction Center Norman OK
1035 PM CDT Thu Jul 16 2026
Areas affected...northeast North Dakota
Concerning...Severe Thunderstorm Watch 491...
Valid 170335Z - 170430Z
The severe weather threat for Severe Thunderstorm Watch 491
continues.
SUMMARY...The severe weather threat is expected to diminish over the
next hour.
DISCUSSION...Recent radar and satellite data indicate a gradual
weakening of ongoing storms across portions of Wells, Eddy, and
Foster Counties. The onset of nocturnal cooling is resulting in
increasing convective inhibition, and in the absence of appreciable
forcing for ascent, that trend is likely to continue along with a
decreasing severe weather threat by 04Z (11 PM CDT).
..Mead.. 07/17/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FGF...BIS...
LAT...LON 47579992 47939986 48099915 47929855 47899851 47599842
47199892 47189928 47189979 47579992
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SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Thu Jul 16 2026
Valid 170100Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
WESTERN MONTANA AND EASTERN NORTH DAKOTA INTO WESTERN MINNESOTA...
...SUMMARY...
Severe thunderstorms capable of producing large hail and gusty winds
remain possible across parts of the northern Rockies this evening.
Severe storms with hail and a tornado or two are also expcted over
parts of the Upper Midwest into tonight.
...Northern Rockies...
Evening water vapor imagery showed a very large upper ridge centered
over the CONUS, with a broad plume of monsoon moisture east of an
upper low off the coast of the Olympic Peninsula. Numerous
thunderstorms are ongoing over the Intermountain West and northern
Rockies this evening and should persist for several more hours
tonight.
The strongest of these storms, including some supercells, should
persist over parts of the eastern ID panhandle and western MT this
evening. Here, moderate buoyancy and 40+ kt of effective shear will
continue to favor storm organization. Hail is likely, along with
some potential for severe gusts given steep lapse rates in the lower
and middle troposphere.
...Eastern into western MN...
At the crest of the expansive upper ride, several weak vorticity
maxima and jet streak were migrating along the Canadian/ND border.
An effective warm front/modified outflow boundary was observed from
near the international border into western MN. South of the front,
surface temperatures in the 90s and dewpoints in the lower to middle
70s F are supporting a very unstable air mass with MLCAPE of
4000-5000 J/kg. Veering wind profiles along and south of the warm
front will favor supercells or organized clusters this evening into
tonight as developing convection spreads southeastward toward the
Red River Valley. Despite only modest mid-level lapse rates, strong
to extreme buoyancy and 35-40 kt of deep-layer vertical shear will
support a risk for large hail (some 2+ in) with dominant supercells.
Backed low-level flow and enhanced ESRH along the cool side of the
boundary could support a tornado or two as well.
The primary focus for the severe storms will be along the warm front
where convergence is maximized, though isolated storms ongoing
farther southwest are possible with a localized threat for hail and
damaging winds in the more strongly mixed air mass. A Level 2 Slight
Risk has been introduced to cover the increase in severe risk
through this evening from eastern ND into western MN.
...Elsewhere...
Strong to severe storms have largely exited the eastern seaboard
this evening. Additional disorganized storms over the southeastern
US and southern Plains should linger into the overnight hours while
steadily weakening. Waning buoyancy and meager deep-layer vertical
shear should limit severe potential.
..Lyons.. 07/17/2026
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SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Thu Jul 16 2026
Valid 170100Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
WESTERN MONTANA AND EASTERN NORTH DAKOTA INTO WESTERN MINNESOTA...
...SUMMARY...
Severe thunderstorms capable of producing large hail and gusty winds
remain possible across parts of the northern Rockies this evening.
Severe storms with hail and a tornado or two are also expcted over
parts of the Upper Midwest into tonight.
...Northern Rockies...
Evening water vapor imagery showed a very large upper ridge centered
over the CONUS, with a broad plume of monsoon moisture east of an
upper low off the coast of the Olympic Peninsula. Numerous
thunderstorms are ongoing over the Intermountain West and northern
Rockies this evening and should persist for several more hours
tonight.
The strongest of these storms, including some supercells, should
persist over parts of the eastern ID panhandle and western MT this
evening. Here, moderate buoyancy and 40+ kt of effective shear will
continue to favor storm organization. Hail is likely, along with
some potential for severe gusts given steep lapse rates in the lower
and middle troposphere.
...Eastern into western MN...
At the crest of the expansive upper ride, several weak vorticity
maxima and jet streak were migrating along the Canadian/ND border.
An effective warm front/modified outflow boundary was observed from
near the international border into western MN. South of the front,
surface temperatures in the 90s and dewpoints in the lower to middle
70s F are supporting a very unstable air mass with MLCAPE of
4000-5000 J/kg. Veering wind profiles along and south of the warm
front will favor supercells or organized clusters this evening into
tonight as developing convection spreads southeastward toward the
Red River Valley. Despite only modest mid-level lapse rates, strong
to extreme buoyancy and 35-40 kt of deep-layer vertical shear will
support a risk for large hail (some 2+ in) with dominant supercells.
Backed low-level flow and enhanced ESRH along the cool side of the
boundary could support a tornado or two as well.
The primary focus for the severe storms will be along the warm front
where convergence is maximized, though isolated storms ongoing
farther southwest are possible with a localized threat for hail and
damaging winds in the more strongly mixed air mass. A Level 2 Slight
Risk has been introduced to cover the increase in severe risk
through this evening from eastern ND into western MN.
...Elsewhere...
Strong to severe storms have largely exited the eastern seaboard
this evening. Additional disorganized storms over the southeastern
US and southern Plains should linger into the overnight hours while
steadily weakening. Waning buoyancy and meager deep-layer vertical
shear should limit severe potential.
..Lyons.. 07/17/2026
Read more
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0759 PM CDT Thu Jul 16 2026
Valid 170100Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
WESTERN MONTANA AND EASTERN NORTH DAKOTA INTO WESTERN MINNESOTA...
...SUMMARY...
Severe thunderstorms capable of producing large hail and gusty winds
remain possible across parts of the northern Rockies this evening.
Severe storms with hail and a tornado or two are also expcted over
parts of the Upper Midwest into tonight.
...Northern Rockies...
Evening water vapor imagery showed a very large upper ridge centered
over the CONUS, with a broad plume of monsoon moisture east of an
upper low off the coast of the Olympic Peninsula. Numerous
thunderstorms are ongoing over the Intermountain West and northern
Rockies this evening and should persist for several more hours
tonight.
The strongest of these storms, including some supercells, should
persist over parts of the eastern ID panhandle and western MT this
evening. Here, moderate buoyancy and 40+ kt of effective shear will
continue to favor storm organization. Hail is likely, along with
some potential for severe gusts given steep lapse rates in the lower
and middle troposphere.
...Eastern into western MN...
At the crest of the expansive upper ride, several weak vorticity
maxima and jet streak were migrating along the Canadian/ND border.
An effective warm front/modified outflow boundary was observed from
near the international border into western MN. South of the front,
surface temperatures in the 90s and dewpoints in the lower to middle
70s F are supporting a very unstable air mass with MLCAPE of
4000-5000 J/kg. Veering wind profiles along and south of the warm
front will favor supercells or organized clusters this evening into
tonight as developing convection spreads southeastward toward the
Red River Valley. Despite only modest mid-level lapse rates, strong
to extreme buoyancy and 35-40 kt of deep-layer vertical shear will
support a risk for large hail (some 2+ in) with dominant supercells.
Backed low-level flow and enhanced ESRH along the cool side of the
boundary could support a tornado or two as well.
The primary focus for the severe storms will be along the warm front
where convergence is maximized, though isolated storms ongoing
farther southwest are possible with a localized threat for hail and
damaging winds in the more strongly mixed air mass. A Level 2 Slight
Risk has been introduced to cover the increase in severe risk
through this evening from eastern ND into western MN.
...Elsewhere...
Strong to severe storms have largely exited the eastern seaboard
this evening. Additional disorganized storms over the southeastern
US and southern Plains should linger into the overnight hours while
steadily weakening. Waning buoyancy and meager deep-layer vertical
shear should limit severe potential.
..Lyons.. 07/17/2026
Read more
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0105 AM CDT Thu Jul 16 2026
Valid 171200Z - 181200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF NORTHERN IDAHO AND WESTERN MONTANA AS WELL AS PORTIONS OF THE
UPPER MIDWEST AND NORTHERN GREAT LAKES...
...SUMMARY...
Strong to potentially severe storms are possible on Friday across
parts of western Montana and northern Idaho, and also across parts
of the Upper Great Lakes region.
... Parts of the Upper Midwest and Great Lakes ...
A subtle mid-level vorticity maximum evident in the 16/00 UTC
guidance is expected to move southeastward across northern Minnesota
and the Upper Great Lakes on Friday morning, supporting ongoing
thunderstorms across the Arrowhead of Minnesota. This activity
should spread southeastward through the morning with at least a
marginal severe hail/wind threat.
During the day, a surface frontal zone draped from northern
Illinois/Indiana should begin to lift northward, ahead of a surface
cold front moving through the northern Plains. To the south of the
warm front and ahead of the cold front, diurnal heating may be
somewhat muted by smoke and residual cloud cover from morning
convection. However, increasing low-level moisture should still
support moderate destabilization by the afternoon, especially where
stronger diurnal heating occurs. Moderate mid-level northwesterly
flow will provide enough vertical shear to support organized storms.
As the stronger mid-level wave approaches the region during the late
afternoon and evening, some potential exists for surface-based
thunderstorm redevelopment -- especially near the intersection of
the cold front and effective warm front. Large hail and strong
thunderstorm winds will be possible with these storms, and the
low-level wind field would support at least some potential for a
tornado with any sustained surface-based storm during the evening.
With time this activity should evolve into one or more clusters of
thunderstorms moving southeast overnight across the northern Great
Lakes.
... Western Montana and Northern Idaho ...
A relatively favorable thermodynamic environment will once again be
in place across parts of western Montana and northern Idaho by
Friday afternoon. Relatively steep low- and mid-level lapse rates,
sufficient moisture, and diurnal heating should support afternoon
SBCAPE values in the 1000-1500 J/kg range, as suggested by the
20260716 00UTC HREF. Mid-/upper-level flow will be less than in
previous days as the region becomes increasingly displaced from a
mid-/upper-level trough/low moving northward into southwest Canada.
That said, effective-layer shear on the order of 25-35 knots will be
possible, especially where east/southeasterly surface winds are
maintained.
Scattered thunderstorms are expected to develop during the afternoon
and evening hours. The strongest thunderstorm clusters will be
capable of large hail. Strong to severe thunderstorm gusts will be
possible as well, especially where convective outflows can
consolidate amid the steep low-/mid-level lapse rates. Most 16/00
UTC HREF members show explicit convective outflow gusts approaching
60 mph, supporting a localized severe threat.
If convective coverage appears greater than currently forecast,
severe probabilities may need to be increased in subsequent
outlooks.
... Ohio Valley ...
Scattered to numerous thunderstorms are expected to develop during
the afternoon within a moist, moderately unstable, and weakly capped
environment. Localized downburst winds could occur within this
environment, though deep-layer flow/shear appears too weak to
support an organized severe threat. Additionally, 16/00 UTC guidance
suggests early initiation across the region, which would limit the
development of widespread steep low-level lapse rates, which may
provide some limit on a more widespread, storm-scale driven wind
threat. This region will continue to be evaluated in subsequent
outlooks.
..Marsh.. 07/16/2026
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1231 AM CDT Thu Jul 16 2026
Valid 171200Z - 181200Z
...Synopsis...
An upper ridge will amplify over much of the Intermountain West and
central U.S. Evacuation of deeper monsoon moisture hastened by dry
southwest flow south of a Pacific Northwest trough will bring dry
and breezy conditions to portions of CA, OR and NV Friday.
Similarly, daily shower and thunderstorm activity will generally be
shifted farther east with dry conditions returning to the Pacific
Northwest.
...Northeastern California, south-central OR and far northwestern
NV...
Dry southwest flow aloft coupled with a diffuse surface low in the
Great Basin will enhance low-level southwest winds across
northeastern CA and adjacent OR and NV areas. Efficient boundary
layer mixing under sunny skies will manifest in southwest winds at
the surface of around 15 mph during Friday afternoon. The winds
coupled with RH of 10-15% will bring an elevated fire weather
concern to the area amid dry fuels.
...Columbia Basin...
Dry south to southwest flow is expected to return Friday across
portions of the Columbia Basin and Okanogan Valley as an upper low
ejects into British Columbia. South/southwest winds of around 15 mph
and RH dropping to 15% should briefly elevate fire weather concerns
Friday. However, preceding rainfall could mitigate the fire weather
threat, precluding introduction of highlights for this outlook
issuance.
..Williams.. 07/16/2026
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1231 AM CDT Thu Jul 16 2026
Valid 161200Z - 171200Z
...Synopsis...
An upper-level low with an attendant mid-level jet will pivot into
the Pacific Northwest today. This feature, in addition to monsoon
moisture and daytime instability, will yield a mix of wet/dry
showers and thunderstorms across much of eastern WA and the ID
Panhandle today. A deepening lee surface trough across eastern OR/WA
in response to the advancing upper wave should allow for drier
southwest flow (and increasing fire weather concerns) to return to
portions of northeastern CA, far northwestern NV and south-central
OR this afternoon. Dry, northwest flow across the central/southern
CA coastal ranges and adjacent Central Valley will promote another
day of elevated fire weather concerns. Broad development of isolated
showers and thunderstorms across much of the Intermountain West is
expected today with deeper monsoon moisture in place. This
convection should be slower moving and mainly terrain bound,
limiting lightning ignition potential.
...Washington and far northern ID Panhandle...
A 50-60 knot mid-level jet ahead of a parent upper low will push
into the WA/OR Cascades through the day. Forcing for ascent amid
plentiful monsoon moisture, evolving daytime instability and
resultant fast north/northeast storm motions will limit
precipitation in some rain cores. However, the most likely outcome
will be a mix of wet and dry thunderstorms through today.
Nonetheless, fuels remain receptive with ERCs hovering around the
90th percentile which should facilitate some new ignitions (with
nascent fires from overnight thunderstorms already occurring across
north-central OR). A more pronounced dry thunderstorm environment
emerges across northeastern NV and southwestern ID this afternoon,
but recent rainfall has mitigated fuel receptivity which should
reduce the overall threat.
...Portions of central and southern California and Central Valley...
Breezy westerly/northwesterly winds and enhanced downslope drying
over portions of central and southern CA is expected again today,
albeit on a slightly reduced scale. Latest model guidance shows
lower HREF/REFS probabilities of sustained winds of 15 mph or
greater across the Central Valley, confining the threat to adjoining
coastal ranges and terrain gap features this afternoon where RH will
near 15%. As such, trimmed eastern extent of elevated highlights
across the Central Valley.
...Northeastern California, northwestern Nevada and south-central
Oregon...
Considerably drier southwest flow will encompass northeastern CA,
northwestern NV and southeastern OR, aided by the advancing Pacific
Northwest upper low and related lee surface trough. West/southwest
winds of around 15 mph and RH as low as 10% during peak boundary
layer mixing will promote an elevated fire weather threat this
afternoon where recent rainfall was minimal.
..Williams.. 07/16/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1218 AM CDT Thu Jul 16 2026
Valid 161200Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
WESTERN MONTANA...
...SUMMARY...
Severe thunderstorms will be possible across parts of western
Montana, mainly Thursday afternoon and evening. Locally damaging
winds may also occur across parts of New England, the Upper Midwest,
and the Mid-Atlantic.
...Northern Rockies...
An upper low will skim the Pacific Northwest coast as it lifts
northward through the period. Meanwhile, upper ridging will persist
across much of the Rockies to the Plains. Wedged between the upper
low and the western periphery of the upper ridging, a belt of
enhanced south/southwesterly deep-layer flow will overspread the
northern Rockies. Easterly low-level flow will transport 50s F
dewpoints across region beneath steep midlevel lapse rates. This
will support moderate destabilization (1000-2000 J/kg MLCAPE).
Scattered thunderstorms will develop during the afternoon.
Vertically veering wind profiles and increasing flow aloft will
result in 30+ kt effective shear magnitudes. Organized cells will
pose a risk for strong wind gusts and hail across much of the
region. The greatest risk for 1+ inch hail will be across portions
of western MT.
...New England...
A vigorous upper shortwave trough will move across the region
through evening. Strong west/northwest deep-layer flow is evident in
forecast soundings, with 40+ kt effective shear magnitudes likely.
Boundary layer moisture will be somewhat muted compared to the
previous few days, with dewpoints generally in the 50s F. Stronger
heating is expected to the north of the more prominent smoke plume
across southern New England, aiding in steepening low-level lapse
rates. While instability will remain modest, strong flow and steep
low-level lapse rates may support isolated strong/locally damaging
wind gusts as convection spreads southeast from Quebec and across
portions of northern New England through the afternoon.
...Southern PA/Mid-Atlantic vicinity...
Strong mid/upper-level flow will overspread the region on the
southern periphery of the upper shortwave trough moving across New
England. A surface front is expected to drop southward through the
day, approaching the PA/MD border vicinity by late afternoon. Rich
boundary layer moisture will be in place ahead of the surface front
and beneath steep midlevel lapse rates. This will foster a corridor
of 2000+ J/kg MLCAPE. Furthermore, forecast soundings show 30-40 kt
effective shear magnitudes and steep low-level lapse rates. This
environment generally should support organized cells/line segments.
However, convective coverage is uncertain given stronger forcing for
ascent focused north of the area. Additionally, it is uncertain if
smoke will continue to have a deleterious impact on an otherwise
favorable severe storm environment. Given conditional potential for
at least locally damaging gusts, have included low severe wind
probabilities.
...ND/MN...
A series of convectively enhanced vorticity maxima will migrate
across the Canadian Prairies atop the upper ridge and through
northwesterly flow aloft into parts of ND and northern MN this
afternoon into tonight. At the surface, a weak low and surface front
will move across ND into northern MN during the evening and
overnight hours. South/southeasterly low-level flow will maintain a
moisture-rich boundary layer, supporting a corridor of modest
destabilization. Forecast soundings show supercell wind profiles,
but also increasing capping through the late afternoon/evening.
Nevertheless, most guidance develops convection across southern
Manitoba into northeast ND during the evening, spreading
east/southeast across northern MN during the nighttime hours. Some
risk for strong gusts and marginal hail appears possible,
necessitating low severe probabilities.
...AZ...
Thunderstorms are expected once again to develop over higher terrain
this afternoon/evening and spread westward across portions of
central/southern AZ. Deep layer flow will be weaker compared to
previous days, but modest instability and steep lapse rates amid
strong heating could support sporadic strong gusts.
..Leitman/Lyons.. 07/16/2026
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SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook RESENT 1
NWS Storm Prediction Center Norman OK
0933 PM CDT Wed Jul 15 2026
Valid 160100Z - 161200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS CENTRAL
TX...SOUTHERN/CENTRAL AZ...SOUTHEAST MT...AND PORTIONS OF CENTRAL OR
INTO SOUTHERN WA...
...SUMMARY...
Isolated damaging winds are possible for portions of the northern
Rockies/High Plains, Pacific Northwest, and Arizona into the early
overnight hours. A brief tornado or two may also occur across parts
of south-central Texas.
...Mid-Atlantic/Northeast...
Severe probabilities have been removed from the Northeast states
with the 01z update. The 00z OKX RAOB indicated ample inhibition,
which should suppress convection the remainder of the evening.
Despite strong deep-layer northwesterly flow and modest midlevel
lapse rates supporting elevated instability, it is unlikely
additional convection will develop overnight as a midlevel shortwave
impulse increasingly moves offshore over the Atlantic.
Some guidance suggests that convection ongoing over southern Lower
MI may continue to develop/percolate southeast overnight across Lake
Erie and into northeast OH/northwest PA within strong northwesterly
mid/upper flow. The 00z PIT RAOB shows steep lapse rates and large
instability. However, inhibition should increase with loss of
daytime heating. An isolated strong storm producing small hail
cannot be ruled out, but overall severe potential appears limited
given time of day and nebulous forcing for ascent.
...Central Texas...
Rounds of thunderstorms will continue overnight as lobes of
convectively enhanced vorticity maxima rotate around the mid/upper
low centered over west-central TX. Low-level warm advection will
persist through the night, maintaining rich boundary layer moisture,
maintaining at least modest low-level instability. Vertically
veering low-level wind profiles will maintain 0-1 km SRH around
100-200 m2/s2, and a tornado or two will remain possible.
...AZ...
Strong thunderstorms could produce locally damaging/severe gusty
outflow winds through late evening. Reference MCD 1628 for
information on short term severe potential.
...MT/WY...
Severe probabilities have mostly be removed from WY and confined to
MT, where modest instability overlaps with strong effective shear
magnitudes. Isolated strong wind gusts remain possible through late
evening as convection shifts east toward a better low-level lapse
rate environment.
...WA/OR...
Scattered high-based showers and thunderstorms will persist tonight
across central OR into south-central WA. A belt of 30-40 kt
effective shear magnitudes may provide sufficient support within the
weakly unstable airmass for a couple of strong storms. Steep lapse
rates will favor strong outflow winds with this convection.
..Leitman.. 07/16/2026
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SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0740 PM CDT Mon Jul 13 2026
Valid 140100Z - 141200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTH FLORIDA...SOUTH-CENTRAL ARIZONA AND WESTERN MONTANA...
...SUMMARY...
Thunderstorms with isolated severe gusts will be possible this
evening across parts of south Florida, south-central Arizona, and
western Montana.
...South Florida...
Very moist air is in place across south Florida, where surface
dewpoints are in the 70s F. Warm surface temperatures have enabled a
pocket of strong instability to develop over south Florida. The 00Z
sounding at Miami has SBCAPE around 3500 J/kg. Scattered
thunderstorms are ongoing from near the instability max
northeastward to near Lake Okeechobee. In addition to the high
surface dewpoints, RAP Forecast soundings in south Florida early
this evening show sufficiently steep lapse rates for isolated severe
gusts. The threat is expected to end over the next hour or so.
...South-central Arizona...
At the surface, an axis of low-level convergence and instability is
located over southeast Arizona. Scattered thunderstorms have
developed near the instability axis, and these storms will continue
to move westward across south-central Arizona early this evening.
Large temperature-dewpoint spreads and steep low-level lapse rates
will support a few severe wind gusts.
...Western Montana...
At mid-levels, southwesterly flow is located over much of the
northwestern U.S. this evening. At the surface, upslope flow is in
place from the northern High Plains westward to the northern
Rockies. An axis of instability is analyzed by the RAP from the
higher terrain in southwestern Montana into the lower elevations of
central Montana, where SBCAPE has peaked near 1500 J/kg according to
the RAP. Over the next few hours, thunderstorms are expected to
develop in the northern Rockies. A few of these cells may persist
and move into west-central Montana later this evening. Moderate
deep-layer shear and steep low to mid-level lapse rates could
support an isolated threat for severe wind gusts.
..Broyles.. 07/14/2026
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MD 1611 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF SOUTHEASTERN THROUGH CENTRAL ARIZONA
Mesoscale Discussion 1611
NWS Storm Prediction Center Norman OK
0254 PM CDT Mon Jul 13 2026
Areas affected...parts of southeastern through central Arizona
Concerning...Severe potential...Watch unlikely
Valid 131954Z - 132230Z
Probability of Watch Issuance...5 percent
SUMMARY...Widely scattered to scattered intensifying thunderstorms
are increasingly probable by 3-5 PM MST, accompanied by a few
strong, but generally localized, downbursts.
DISCUSSION...A modestly deep-mixed boundary layer is evolving, with
continued daytime heating. Surface temperature/dew point spreads
are increasing in excess of 30-35 degrees F, as temperatures warm
through the 90s. Latest objective analysis suggests that this
environment is also becoming characterized by modest instability,
with CAPE now on the order of 1000 J/kg across the deserts around
Tucson, northwestward toward the Greater Phoenix vicinity.
In response to this destabilization, deepening convection is evident
across the higher terrain of southeastern Arizona, as well as along
the Mogollon Rim vicinity, beneath 10-15 kt southeasterly deep-layer
mean flow. Over the next few hours, scattered thunderstorms appear
likely to continue to initiate and gradually intensify while
propagating northwestward across southeastern into central Arizona.
As it does, the most vigorous cells will pose increasing potential
to produce generally localized strong downbursts during the peak
late afternoon heating.
It is possible that orographic forcing near the Rim could support a
bit more notable upscale growth or clustering of convection, but
steering flow may not support much, if any, propagation and
intensification away from the higher terrain.
..Kerr.. 07/13/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TWC...FGZ...PSR...
LAT...LON 34551179 33491015 32770954 31550936 31411065 32051108
33531243 34031246 34551179
MOST PROBABLE PEAK WIND GUST...55-70 MPH
Read more
MD 1612 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF THE CENTRAL AND EASTERN FLORIDA PENINSULA
Mesoscale Discussion 1612
NWS Storm Prediction Center Norman OK
0424 PM CDT Mon Jul 13 2026
Areas affected...Portions of the central and eastern Florida
Peninsula
Concerning...Severe potential...Watch unlikely
Valid 132124Z - 132330Z
Probability of Watch Issuance...5 percent
SUMMARY...Scattered thunderstorms will continue to develop and move
southeastward across the central FL Peninsula through this evening,
accompanied by damaging wind gusts up to 60 mph.
DISCUSSION...Surface temperatures in the low 90s combined with
dewpoints in the mid to upper 70s are yielding a moderately unstable
environment ahead of a cluster of congealing thunderstorms moving
southeast across the central FL Peninsula late this afternoon.
Low-level lapse rates peaking near 7.5 C/km, storm mergers, and a
deepening cold pool will continue to support a threat of severe,
damaging wind gusts up to 60 mph through at least 23Z. Given the
localized nature of the threat, a watch is not expected at this
time.
..Barnes/Smith.. 07/13/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MLB...TBW...
LAT...LON 28508104 28978054 28868039 27908003 27308046 27258116
27438167 27678183 27938190 28238168 28508104
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
Read more
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0354 PM CDT Mon Jul 13 2026
Valid 151200Z - 211200Z
...Synopsis...
A strong upper high will persist over the central/northern Plains
through the end of this week into the early weekend. Upper-level
troughing will continue near and off the Pacific Northwest coast
with monsoonal moisture streaming northward across much of the
Intermountain West this week; meanwhile, daily monsoonal
thunderstorms are likely across the Southwest into the Great Basin.
An upper-level trough is forecast to move near/into the Pacific
Northwest early Day 4/Thursday, potentially suppressing moisture
south and eastward. However, model spread and ambiguity in the
spatial extent/strength of troughing yields significant uncertainty
in the progression of the upper pattern across the West. Farther
east, a deep upper-level trough is expected to weaken the ridge over
the Great Lakes and Northeast as it digs southward on Days
2-3/Tuesday-Wednesday, leading to unsettled conditions across the
region through the remainder of the forecast period.
...Central to northern High Plains...
Hot, dry, and breezy conditions are likely across portions of
eastern Wyoming, western South Dakota, western Nebraska and eastern
Colorado on Day 3/Wednesday through at least Day 4/Thursday. While
RH is expected to recover overnight, south-southeast winds are
likely to remain breezy amid dry fuels and hot daytime temperatures.
40% Critical probabilities have been maintained; however, may need
to be confined in future outlooks as predictability increases in the
evolution of the upper pattern.
...Portions of northeastern California and the Central Valley,
western Great Basin, and far south-central Oregon...
Warm daytime temperatures and low RH will contribute to drying fuels
across the California Coastal Ranges into the Central Valley. ERCs
are forecast to approach the 90-95th percentile mid-late week amid
dry and breezy conditions, supporting any new ignitions and the
emergence of lightning holdovers from wet/dry thunderstorms early in
the forecast period. 40% Critical probabilities remain on Days
3-4/Wednesday-Thursday to account for this threat. Farther north,
guidance has backed off on the timing of stronger winds overlapping
low RH, resulting in 40% Critical probabilities being removed on Day
3/Wednesday across northeastern California and adjacent areas. Yet,
the potential for stronger flow amid a returning dry airmass on Day
4/Thursday warrants the introduction of 40% Critical probabilities.
..Elizalde-Garcia.. 07/13/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0354 PM CDT Mon Jul 13 2026
Valid 151200Z - 211200Z
...Synopsis...
A strong upper high will persist over the central/northern Plains
through the end of this week into the early weekend. Upper-level
troughing will continue near and off the Pacific Northwest coast
with monsoonal moisture streaming northward across much of the
Intermountain West this week; meanwhile, daily monsoonal
thunderstorms are likely across the Southwest into the Great Basin.
An upper-level trough is forecast to move near/into the Pacific
Northwest early Day 4/Thursday, potentially suppressing moisture
south and eastward. However, model spread and ambiguity in the
spatial extent/strength of troughing yields significant uncertainty
in the progression of the upper pattern across the West. Farther
east, a deep upper-level trough is expected to weaken the ridge over
the Great Lakes and Northeast as it digs southward on Days
2-3/Tuesday-Wednesday, leading to unsettled conditions across the
region through the remainder of the forecast period.
...Central to northern High Plains...
Hot, dry, and breezy conditions are likely across portions of
eastern Wyoming, western South Dakota, western Nebraska and eastern
Colorado on Day 3/Wednesday through at least Day 4/Thursday. While
RH is expected to recover overnight, south-southeast winds are
likely to remain breezy amid dry fuels and hot daytime temperatures.
40% Critical probabilities have been maintained; however, may need
to be confined in future outlooks as predictability increases in the
evolution of the upper pattern.
...Portions of northeastern California and the Central Valley,
western Great Basin, and far south-central Oregon...
Warm daytime temperatures and low RH will contribute to drying fuels
across the California Coastal Ranges into the Central Valley. ERCs
are forecast to approach the 90-95th percentile mid-late week amid
dry and breezy conditions, supporting any new ignitions and the
emergence of lightning holdovers from wet/dry thunderstorms early in
the forecast period. 40% Critical probabilities remain on Days
3-4/Wednesday-Thursday to account for this threat. Farther north,
guidance has backed off on the timing of stronger winds overlapping
low RH, resulting in 40% Critical probabilities being removed on Day
3/Wednesday across northeastern California and adjacent areas. Yet,
the potential for stronger flow amid a returning dry airmass on Day
4/Thursday warrants the introduction of 40% Critical probabilities.
..Elizalde-Garcia.. 07/13/2026
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0233 PM CDT Mon Jul 13 2026
Valid 132000Z - 141200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
CENTRAL MONTANA...SOUTHERN INTO CENTRAL ARIZONA...AND THE FLORIDA
PENINSULA INTO EXTREME SOUTHERN SOUTH CAROLINA...
...SUMMARY...
Thunderstorms with isolated strong to severe winds are still
possible this afternoon and evening across parts of the Southeast,
southern into central Arizona, and Montana.
...20Z Update...
The previous forecast (see below) remains unchanged, with only minor
changes made to the thunder/severe probabilities to reflect the
latest observations and guidance consensus.
..Squitieri.. 07/13/2026
.PREV DISCUSSION... /ISSUED 1101 AM CDT Mon Jul 13 2026/
An expansive upper ridge over the northern Plains will dominate the
weather across the US today, with only small areas of risk of severe
storms.
...FL/GA...
A hot and humid air mass is present today over the FL Peninsula into
parts of southeast GA/SC. Scattered afternoon thunderstorms are
expected to form in this regime, with the strongest cells capable of
gusty/damaging winds.
...AZ...
Widespread convection yesterday has resulted in a moist boundary
layer across southern AZ, where strong heating will occur again
today. This will lead to another round of scattered storms moving
off the higher terrain of eastern AZ and speading westward into the
Deserts. A few of the storms may produce gusty/damaging winds.
...MT...
Morning CAM solutions are consistent on the forecast of a cluster of
high-based thunderstorms forming over the mountains of southern MT
and tracking north-northeastward during the evening. Forecast
soundings would support some risk of a gusty/damaging winds in these
storms.
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