RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Sat Jun 27 17:43:02 UTC 2026.
MD 1348 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR EASTERN MONTANA AND NORTHEAST WYOMING
Mesoscale Discussion 1348
NWS Storm Prediction Center Norman OK
1240 PM CDT Sat Jun 27 2026
Areas affected...eastern Montana and northeast Wyoming
Concerning...Severe potential...Watch likely
Valid 271740Z - 272015Z
Probability of Watch Issuance...95 percent
SUMMARY...Severe storms are expected to develop by 19-20Z with an
associated risk for wind gusts of 80+ mph, large to very large hail
of 2+ inches, and perhaps a tornado or two. A watch is likely.
DISCUSSION...Latest mesoanalysis placed a surface low over far
southeast MT or northeast WY with an associated stationary front or
trough stretching from northwest ND to the vicinity of the Big Horn
Mountains in north-central WY. A corridor of higher boundary-layer
moisture content resides along and to the north of the front, which
coincides with the northern edge of an EML plume, supporting MLCAPE
of 1000-1500 J/kg, per latest objective analysis. Daytime heating
and increasing height falls/forcing for ascent are expected to
support further air mass destabilization by early to mid afternoon,
while a capping inversion for surface-based parcels becomes
progressively weaker.
Latest short-term model guidance indicates an increased likelihood
of surface-based thunderstorm development by 19-20Z along the Big
Horn Mountains. That notion is corroborated by the deepening cumulus
field along that terrain feature, per recent visible satellite
trends. RAP-based forecast soundings in that area indicate 40-50 kt
of north-northeast deep-layer shear supportive of supercells as the
initial storm mode with the primary hazard being large to very large
hail. While low-level shear isn't forecast to be particularly
strong, the presence of the front may serve as a local vorticity
source for some tornado threat. By late afternoon into early
evening, there is good model agreement in storms coalescing into a
broader-scale, bowing structure capable of swaths of damaging winds,
including gusts of 80+ mph.
..Mead/Guyer.. 06/27/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...UNR...BYZ...GGW...RIW...
LAT...LON 44850544 44650596 44430686 44790821 45260856 46460754
47520711 47920690 48380577 48090460 47800451 46950419
46080435 45130465 44850544
MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...75-90 MPH
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN
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MD 1347 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHERN UTAH...SOUTHEAST IDAHO...AND WESTERN WYOMING
Mesoscale Discussion 1347
NWS Storm Prediction Center Norman OK
1026 AM CDT Sat Jun 27 2026
Areas affected...northern Utah...southeast Idaho...and western
Wyoming
Concerning...Severe potential...Watch unlikely
Valid 271526Z - 271800Z
Probability of Watch Issuance...20 percent
SUMMARY...The potential for a few severe storms capable of strong
wind gusts and large hail is expected to increase by late morning
into early afternoon. The current expectation is that severe weather
coverage will remain too isolated to warrant a watch issuance.
DISCUSSION...Within the left exit region of mid/upper-level wind
maxima propagating through the Sierra Nevada into the Great Basin, a
fairly long-lived cluster of thunderstorms has persisted this
morning across north-central into northeast NV. Downstream from that
convection, a fairly moist air mass is currently being observed
across northern UT with dewpoints in the 40s to low 50s. The
moisture combined with steep mid-level lapse rates is already
contributing to MLCAPE as high as 500 J/kg across portions of
northern UT as of 15Z. Additional destabilization is anticipated
through the remainder of the morning into afternoon with the
continued warming of the boundary layer.
Consistent with current observational data, latest convection-
allowing model guidance suggests a climatologically early increase
in severe storm potential, initially across northern UT and
southeast ID with activity subsequently spreading into western WY.
Steadily strengthening mid/upper-level winds will result in
sufficiently strong vertical shear for transient supercell and
bowing structures capable of isolated occurrences of severe wind
gusts and large hail.
..Mead/Guyer.. 06/27/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...RIW...SLC...PIH...
LAT...LON 41101394 42091363 43011206 44031086 44070973 43780918
43090917 42350919 41710990 41131087 40631208 40451291
40431366 41101394
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1142 AM CDT Sat Jun 27 2026
Valid 271630Z - 281200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
NORTHERN HIGH PLAINS...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
TENNESSEE VALLEY TO CAROLINAS...
...SUMMARY...
Severe thunderstorms are likely today across the northern High
Plains including northeast Wyoming and eastern Montana into the
western Dakotas, with storms capable of very large hail, very strong
outflow winds (80+ mph), and tornadoes late this afternoon into
tonight.
...Northern High Plains this afternoon into tonight...
A rather active severe-weather scenario is anticipated regionally
later today, including the potential for intense/locally significant
severe storms. A lead shortwave trough/speed max will continue to
approach through late today, with the exit region of a strong
upper-level jet overspreading the region including 50+ kt
southwesterlies above 5km AGL. Boundary-layer dewpoints in the 60s F
will continue to spread northward regionally, to the east of a
deepening surface low across northeast Wyoming toward the far
western Dakotas, and a sharpening lee trough/dryline across a more
prevalent north/south extent of the High Plains. This low-level
moistening will occur beneath a plume of steep mid-level lapse rates
emanating from the Great Basin and north-central Rockies.
Initial surface-based development is expected near the surface
low/trough near the Big Horn Mountains toward the
Wyoming/Montana/North Dakota border vicinity. The maturing stronger
initial storms will almost certainly be supercellular owing to
moderate to large CAPE and a strong wind field. The risk for large
to very large hail (2-3 inches in diameter) is greatest near this
aforementioned border region where supercells are forecast early in
the convective life cycle, although additional/somewhat more
discrete development will also likely occur a bit later farther
southeastward across northwest South Dakota.
A few tornadoes are also possible particularly in the more
moisture-rich environment near the surface triple point, but
relatively large temperature-dewpoint spreads and a transition to
upscale growth may temper the tornado threat, particularly with
northward extent either side of the Montana/North Dakota border
vicinity. As more storms develop leading to storm mergers and
coalescing outflow, a linear cluster will likely develop into a
maturing/accelerating bow echo into western North Dakota this
evening, with significant/intense thunderstorm winds (80+ mph)
possible.
Severe storms will likely develop eastward tonight across the
Dakotas, and prior to that, diurnally enhanced, but more isolated
intense, development is plausible as far south as western Nebraska
with large hail and damaging winds.
...Northern Intermountain West including northern UT/western WY...
Influenced by a lead shortwave trough/speed max associated with the
prominent upper-level trough centered over the Pacific Northwest,
strong to locally severe thunderstorm potential will probably exist
early today. The prolifically strong wind field and modest
destabilization will tend to focus today across northern Utah,
southeast Idaho into western Wyoming, including the Star Valley
vicinity. Severe-caliber wind gusts and some hail may occur.
...Mid-South/Tennessee/southern Kentucky to North Carolina...
Multiple MCVs, including across far south-central Missouri and
southeast Kansas at midday, will influence the region as they
progress east-southward generally toward Kentucky and Tennessee.
Related flow enhancement is evident in regional WSR-88d VWP data,
and particularly in the 12z Lamont, OK observed sounding (40+ kt
4-9km AGL). See Mesoscale Discussion 1346 for additional short-term
details.
These MCVs will influence and semi-focus thunderstorm development
within a moist and increasingly unstable boundary layer from the
southeast Missouri/northeast Arkansas border vicinity into Kentucky
and Tennessee. This includes the possibility of some supercells and
well-organized clusters in the presence of 35-40 kt effective shear.
Pockets of wind damage will be the most common risk, but some
tornado potential will exist as well. Additional severe storms
capable of wind damage are also expected farther eastward into the
Carolinas this afternoon through around mid-evening.
...Texas Panhandle/West Texas late this afternoon/evening...
Though forcing for ascent will be weak at best this far south,
strong surface heating/mixing along the lee trough/dryline could
support high-based thunderstorm development late this afternoon.
Inverted-V profiles will favor the potential for isolated severe
outflow gusts of 60-75 mph.
..Guyer/Supinie.. 06/27/2026
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1221 PM CDT Sat Jun 27 2026
Valid 281200Z - 291200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE DAKOTAS INTO NORTHERN MINNESOTA...
...SUMMARY...
Severe thunderstorms are possible from the northern Plains into
parts of the Upper Midwest on Sunday. Large to very large hail and
severe winds are the primary hazards.
...Northern Plains/Upper Midwest...
A challenging forecast scenario is expected on Sunday across
portions of the Dakotas into the Upper Midwest. Upper ridging is
expected to amplify over the Mid/Upper MS Valley and western Great
Lakes vicinity. This will result in capping concerns across the
region owing to height rises and warming aloft, especially from the
eastern Dakotas into the Upper Midwest. However, surface troughing
will sharpen and extend southward across the central Dakotas into
the central Plains. Meanwhile, a warm front/moisture gradient will
extend southeastward from northern MN into WI and the southern Lake
Michigan vicinity. Overnight, a surface low is forecast to mildly
deepen somewhere from western NE into SD. Forecast guidance
continues to show uncertainty in the evolution of this feature.
Southeasterly low-level flow will transport rich boundary layer
moisture westward across the region, with dewpoints in the mid 60s
to near 70 F common. A plume of steep midlevel lapse rates will
overspread the Red River and Upper MS Valley during the day, while
lapse rates further west steepen during the evening/overnight. This
will result in corridors of moderate to strong instability within
the warm sector to the east of the surface trough and south of the
warm front. However, given the building upper ridge, capping may
persist across the region, limiting potential for surface-based
convection.
Storms are expected to be ongoing Sunday morning across the eastern
Dakotas and will spread east through the day. While this activity
may be elevated, large hail is possible. A southerly low-level jet
is expected to persist through the daytime, and if storms can become
near-surface based, some damaging wind potential also would exist.
It is unclear how far east this convection may persist as it crests
the building upper ridge.
Overnight, convection is expected to develop near the surface
low/trough on the leading edge of a strong southerly low-level jet
across western or central SD. This activity may be elevated, but
will likely initially be supercell mode with an attendant risk for
large to very large hail. If convection grows upscale, some wind
risk is also possible, but this is more uncertain given capping
concerns.
...Southern Mid-Atlantic...
An MCV is expected to move across the NC vicinity on Sunday. Ahead
of this feature, a seasonally very moist and moderately unstable
airmass will be in place. Deep-layer flow will be modest, but the
MCV may locally enhance vertical shear and provide support for a
band of forward propagating convection moving off the higher terrain
during the after and early evening. Sporadic strong/damaging wind
gusts will be possible with these storms.
...Southern Plains...
A dryline will be oriented from western KS into southwest TX Sunday
afternoon/evening. Strong heating is expected along the boundary
along with sufficient dryline convergence. Deep boundary
circulations and a narrow corridor of moderate instability will
support isolated storm development. Strong downburst/outflow winds
will be possible with these storms as generally weak vertical shear
limits stronger updrafts longevity/organization.
..Leitman.. 06/27/2026
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1143 AM CDT Sat Jun 27 2026
Valid 271700Z - 281200Z
...EXTREMELY CRITICAL FIRE WEATHER AREA FOR PORTIONS OF WESTERN
COLORADO AND EASTERN UTAH INTO THE FOUR CORNERS REGION...
...CRITICAL FIRE WEATHER AREA FOR EASTERN/SOUTHERN
NEVADA...CENTRAL/SOUTHERN UTAH...WESTERN COLORADO...NORTHWESTERN NEW
MEXICO...NORTHERN ARIZONA...AND SOUTH-CENTRAL WYOMING...
***Dangerous fire weather conditions are expected today across
eastern Utah, western Colorado, and the Four Corners region.***
...Morning Update...
A cold front pushed into northern UT and southwestern WY last night,
and has become nearly stationary this morning. South of the front,
very poor to essentially no RH recoveries occurred from
central-southern UT into northern AZ. Current surface observations
depict widespread critical RH values (below 15%) across the CO River
Basin as temperatures rise.
As an unseasonably strong upper trough digs into the western CONUS,
a 40-60 kt 700 mb jet will emerge downstream expanding from the AZ
Strip to the CO West Slope. Minimal cloud cover and deep
boundary-layer mixing will further reinforce stronger winds aloft to
mix down to the surface. Sustained wind speeds of 25-35 mph
(potentially up to 40 mph in terrain favored locations) will combine
with widespread 5-15% RH values atop a receptive fuelscape,
maintaining an Extremely Critical fire weather threat.
Persisting hazardous fire weather conditions -- with potential
lightning holdovers from previous days and many ongoing active
wildfires -- will generate a dangerous long duration burning period
(10+ hours for some locations) as poor overnight humidity recoveries
and lingering breezy conditions will last into Day 2/Sunday.
Additionally, a secondary cold front will push through the Great
Basin this evening, passing through western-central UT between
23z-03z, then stalling overnight along the western edge of the
Colorado Plateau. RH will increase, but winds will shift to
west/northwesterly behind the front with a few hours of strong gusts
(25 mph or greater) before eventually calming some overnight. This
cold front will likely impact a number of fires in southeastern NV
into western/central UT this evening.
See the previous discussion for more information.
..Elizalde-Garcia.. 06/27/2026
.PREV DISCUSSION... /ISSUED 0158 AM CDT Sat Jun 27 2026/
...Synopsis...
***Dangerous fire weather conditions are expected today across
eastern Utah, western Colorado, and the Four Corners region.***
A robust fire weather pattern will continue across portions of the
Great Basin and Southwest today as a seasonably strong mid-level
trough continues to dig into the western CONUS and an attendant
mid-level jet amplifies across portions of the Great Basin.
Continued exceptionally dry and windy conditions following
antecedent dry thunderstorm activity will result in significant fire
weather concerns for any new ignitions, lingering holdovers, and
ongoing large fires across the western CONUS.
...Eastern Utah, western Colorado, and the Four Corners region...
As the aforementioned mid-level jet amplifies across portions of the
Great Basin, a corridor of stronger sustained, southwesterly surface
winds will expand eastward from southeastern Nevada into the Upper
Colorado River Valley. These 25-35 mph (potentially up to 40 mph in
terrain favored locations) winds will overlap very low RH values of
5-15% and receptive fuels (ERCs noted in the 80-95+ percentiles)
that were exacerbated by dry/breezy conditions on Friday. Wind gusts
of 40-50+ mph will also be possible due to deep boundary layer
mixing coupled with the strengthening mid-level jet. This will
promote extremely critical fire weather conditions from the Four
Corners region northward into eastern Utah and western Colorado and
an extended period (10+ hours of for some locations) of critical
fire weather conditions across a broader portion of the Great Basin.
In addition, isolated dry thunderstorm activity on Friday presents
an additional concern for potential lightning holdovers to emerge,
with poor overnight humidity recoveries and lingering breezy
conditions also forecast before another day of critical fire weather
concerns on D2/Sunday. A broader area of elevated wind/RH conditions
is also expected today across much of the Great Basin and Southwest
where sustained southwesterly winds of 15-25 mph overlap low RH of
10-20%.
The primary change with this outlook was a northward expansion of
the Extremely Critical highlights owing to trends within the latest
model guidance. Brief periods of localized extremely critical
conditions are also possible farther west into southeastern Nevada
and portions of north-central Arizona (in the vicinity of recent
wildfire activity); however, confidence in an extended duration of
overlap between 30+ mph sustained winds and RH below 10% is lower
for these locations.
...Please see www.spc.noaa.gov/fire for graphic product...
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