No watches are valid as of Sat Oct 11 20:07:01 UTC 2025.MD 2142 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR MUCH OF NORTHERN AND WESTERN UTAH INTO FAR EAST-CENTRAL NEVADA
Mesoscale Discussion 2142
NWS Storm Prediction Center Norman OK
0256 PM CDT Sat Oct 11 2025
Areas affected...much of northern and western Utah into far
east-central Nevada
Concerning...Severe potential...Watch unlikely
Valid 111956Z - 112230Z
Probability of Watch Issuance...20 percent
SUMMARY...Storms will increase in coverage along a cold front after
20-21Z, and potentially over southern areas ahead of the front.
Locally severe hail or wind gusts are possible.
DISCUSSION...Visible satellite imagery shows strong heating ahead of
the cold front from NV into UT, with substantial cumulus over the
higher terrain, indicative of the moist air mass. Precipitable water
values are approaching 1.00" over parts of the area, as temperatures
aloft gradually cool with the upper trough.
Thunderstorms are already forming along the front from far northwest
UT into eastern ID, where instability is relatively weak. However,
MUCAPE values will increase through the late afternoon and evening,
with MLCAPE over 750 J/kg expected. Moderate deep-layer shear should
support cellular storm mode, especially with any activity that may
develop over east-central into southwest UT ahead of the front.
Despite a linear forcing mechanism along the front, some of these
cells could potentially remain somewhat cellular as well, with hail
near severe levels possible. Increasing/aggregating outflows will
lead to gusty winds as well.
..Jewell/Guyer.. 10/11/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...SLC...VEF...LKN...
LAT...LON 41431316 41901246 41771121 40331132 38821173 37421251
37471455 38641463 40151396 41431316
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Sat Oct 11 2025
Valid 111630Z - 121200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE GREAT
BASIN/SOUTHWEST AND COASTAL NORTH CAROLINA...
...SUMMARY...
Isolated severe thunderstorms are possible this afternoon and
evening across the eastern Great Basin and Southwest. A brief
tornado and occasional strong to severe gusts could occur over the
Outer Banks of North Carolina late tonight and early Sunday morning.
...Great Basin/Southwest...
A prominent trough centered over the Pacific Northwest and northern
California early today will shift eastward over the Great Basin and
northern Intermountain region through tonight. This will be
accompanied by considerable height falls/forcing for ascent and
strengthening deep-layer southwesterly flow and an
eastward-advancing cold front. Ahead of this system, a broad fetch
of tropical moisture emanating from the eastern Pacific will
continue to stream northward, with seasonally rich low/mid-level
moisture expected across parts of the Southwest and southern Great
Basin.
As early day cloudiness quickly shifts eastward and abates, stronger
daytime heating is expected, namely across parts of western/central
Utah and central/southern Arizona. Still, mid-level
lapse rates are expected to remain modest across these areas, and
only weak instability is forecast where filtered diurnal heating can
occur.
Current expectations are for a gradual increase in coverage and
intensity of thunderstorms this afternoon and evening across parts
of the eastern Great Basin into the Southwest as large-scale ascent
associated with the upper trough overspreads these areas. Occasional
hail may occur with the stronger cores, as around 30-40 kt of
deep-layer shear (maximized across Utah) supports organized
updrafts. Otherwise, isolated strong to severe gusts should be the
main threat with scattered to numerous thunderstorms that will
spread east-northeastward through the afternoon and evening.
...Coastal North Carolina/Outer Banks...
A surface low and warm front will approach late tonight/early
Sunday, allowing for upper 60s to low 70s surface dewpoints to
approach and potentially advect inland as east-northeasterly
low-level flow strengthens late tonight. While lapse rates aloft
will remain poor, some buoyancy increase is expected. While inland
warm sector development remains uncertain, ample forecast low-level
and deep-layer shear suggest some risk for a tornado and gusty winds
with any supercell that can form in this environment across the
Outer Banks/coastal North Carolina.
...East-central Montana...
A couple of stronger storms with gusty winds could materialize this
afternoon/early evening across the region, but it still seems that
the potential for severe storms will be limited by meager
moisture/buoyancy.
..Guyer/Moore.. 10/11/2025
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0254 PM CDT Sat Oct 11 2025
Valid 112000Z - 121200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE GREAT
BASIN/SOUTHWEST AND COASTAL NORTH CAROLINA...
...SUMMARY...
Isolated severe thunderstorms are possible this afternoon and
evening across the eastern Great Basin and Southwest. A brief
tornado and occasional strong to severe gusts could occur over the
Outer Banks of North Carolina late tonight and early Sunday morning.
...20z Update...
No changes are needed to the current D1 Convective Outlook. Daytime
heating is underway after morning cloud cover with cu development
evident across the high terrain in northern Arizona and much of
Utah. Convection is likely to increase in coverage and intensity
this afternoon with approaching large scale ascent. The marginally
unstable air mass and strong deep layer shear should support a few
stronger storms capable of a few instances of hail and gusty winds.
The Marginal risk continues across coastal North Carolina/Outer
Banks in anticipation of the surface low/warm front approaching
later this evening. Guidance continues to indicate a few rotating
storms may approach the coast by late evening/early morning with
potential for a tornado or gusty winds.
..Thornton.. 10/11/2025
.PREV DISCUSSION... /ISSUED 1130 AM CDT Sat Oct 11 2025/
...Great Basin/Southwest...
A prominent trough centered over the Pacific Northwest and northern
California early today will shift eastward over the Great Basin and
northern Intermountain region through tonight. This will be
accompanied by considerable height falls/forcing for ascent and
strengthening deep-layer southwesterly flow and an
eastward-advancing cold front. Ahead of this system, a broad fetch
of tropical moisture emanating from the eastern Pacific will
continue to stream northward, with seasonally rich low/mid-level
moisture expected across parts of the Southwest and southern Great
Basin.
As early day cloudiness quickly shifts eastward and abates, stronger
daytime heating is expected, namely across parts of western/central
Utah and central/southern Arizona. Still, mid-level
lapse rates are expected to remain modest across these areas, and
only weak instability is forecast where filtered diurnal heating can
occur.
Current expectations are for a gradual increase in coverage and
intensity of thunderstorms this afternoon and evening across parts
of the eastern Great Basin into the Southwest as large-scale ascent
associated with the upper trough overspreads these areas. Occasional
hail may occur with the stronger cores, as around 30-40 kt of
deep-layer shear (maximized across Utah) supports organized
updrafts. Otherwise, isolated strong to severe gusts should be the
main threat with scattered to numerous thunderstorms that will
spread east-northeastward through the afternoon and evening.
...Coastal North Carolina/Outer Banks...
A surface low and warm front will approach late tonight/early
Sunday, allowing for upper 60s to low 70s surface dewpoints to
approach and potentially advect inland as east-northeasterly
low-level flow strengthens late tonight. While lapse rates aloft
will remain poor, some buoyancy increase is expected. While inland
warm sector development remains uncertain, ample forecast low-level
and deep-layer shear suggest some risk for a tornado and gusty winds
with any supercell that can form in this environment across the
Outer Banks/coastal North Carolina.
...East-central Montana...
A couple of stronger storms with gusty winds could materialize this
afternoon/early evening across the region, but it still seems that
the potential for severe storms will be limited by meager
moisture/buoyancy.
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1152 AM CDT Sat Oct 11 2025
Valid 121200Z - 131200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe-storm risk appears negligible on Sunday into Sunday night.
...East...
A surface cyclone near the coastal Carolinas at 12Z Sunday should
gradually fill as it drifts north, offshore of the Lower
Mid-Atlantic. Convection should primarily segregate into two
corridors of weak elevated activity. One near the quasi-stationary
mid-level low centered in eastern SC and the other in the offshore
low-level warm conveyor that will sustain weakening convection
approaching the Mid-Atlantic to southern New England coast. Largely
poor lapse rates will limit instability/MUCAPE and thunder coverage.
...Northern Plains and Upper Midwest...
Isolated elevated thunderstorms are possible Sunday morning ahead of
the shortwave trough impinging on the northwest ND/far northeast MT
vicinity. Isolated elevated storms are also possible across parts of
the Upper Midwest within the downstream low-level warm conveyor on
Sunday. This will be characterized by weak MUCAPE/mid-level lapse
rates with convection subsiding by Sunday night.
...Southwest...
Scattered afternoon thunderstorms are most probable across southern
AZ into southwest NM. Weak lapse rates above a relatively shallow
mixed boundary layer will limit convective vigor. Isolated elevated
thunderstorms are also possible Sunday night into early morning
Monday both northward to the Four Corners and eastward in the
Southern Plains.
...Pacific Northwest...
A shortwave trough digging south along the Pacific Northwest coast
will aid in sufficient forcing for ascent and steepening of
mid-level lapse rates for an isolated thunderstorm risk on Sunday
afternoon through Sunday night.
..Grams.. 10/11/2025
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