ACUS01 KWNS 111712
SWODY1
SPC AC 111710

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1210 PM CDT Thu Sep 11 2025

Valid 111630Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN
MONTANA INTO WESTERN NORTH DAKOTA...

CORRECTED FOR PROB GRAPHICS

...SUMMARY...
Scattered severe thunderstorms are expected over eastern Montana
into western North Dakota late this afternoon through the evening.
The primary hazards are severe wind gusts and large hail.

...Synopsis...
Water-vapor imagery shows a large cyclone over the West with a
downstream ridge over the Great Plains, and a trough centered over
the Lower Great Lakes. Southwesterly mid to high-level flow extends
from the base of the larger-scale western U.S. trough northeastward
through the Great Basin and into the northern Great Plains. A
mid-level disturbance implied in water-vapor imagery over western
WY, is forecast to move northeast into eastern MT/western ND towards
this evening.

In the low levels, a plume of seasonably rich moisture will protrude
northward from the central Plains into the Dakotas and eastern MT.
A lee trough will extend southward from a surface low over the
northern High Plains.

...Rockies into the northern Plains...
An ongoing cluster of thunderstorms associated with warm-air
advection near the ND/Manitoba border will continue to move
east-northeastward into southern Canada ahead of a pair of MCVs over
western ND/eastern MT. Diurnal heating over the higher terrain from
near the Four Corners northward into southern MT will favor
scattered thunderstorms developing during the midday into the early
afternoon. Storm coverage will increase further over the central
Rockies during the afternoon, with the stronger storms capable of an
isolated hail/wind threat. As the airmass destabilizes over the
plains, particularly across eastern MT within the moist plume
primarily north of the surface low, isolated to scattered storms are
forecast by mid to late afternoon. This initial activity will
probably develop near the MT/WY border with upscale growth into a
cluster possible during the evening. Deep-layer shear supporting
organized storm modes coupled with steep lapse rates, will combine
to aid in several stronger storms capable of a hail/wind threat.
The wind threat will probably continue into ND during the evening
within the terminus region of a 35-40 kt southerly LLJ. A gradual
transition to increasingly elevated convection is expected late as
convective inhibition increases and the overall severe risk lessens.

..15_ows.. 09/11/2025

$$

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ACUS01 KWNS 250620
SWODY1
SPC AC 250618

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1218 AM CST Sun Jan 25 2026

Valid 251200Z - 261200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE EASTERN GULF COAST STATES...

CORRECTED FOR SUBSECTION HEADLINE

...SUMMARY...
Severe thunderstorms are possible across parts of the eastern Gulf
Coast states this morning and afternoon. Damaging gusts and a few
tornadoes are the main concerns.

...Gulf Coast States...

Southern Plains short-wave trough is forecast to eject across the
Arklatex early in the period as a 100+kt 500mb speed max translates
across northern MS, then increases to near 130kt over WV by 26/00z.
Modest midlevel height falls will spread across the Gulf states and
a strong LLJ will respond just downstream from northern AL into the
Middle Atlantic. Associated polar front will surge into MS/southern
LA by sunrise then shift into AL by 18z. Latest model guidance
suggests modified Gulf air mass will advance inland ahead of the
surging boundary such that weak buoyancy will develop within roughly
100mi of the Gulf coast. Forecast soundings suggest SBCAPE on the
order of 500 J/kg could be noted prior to frontal passage where
surface dew points rise into the mid-upper 60s. Given the deep layer
shear, convection that develops within this environment would have
some potential to organize with some supercell risk. For these
reasons have maintained SLGT risk near the Gulf coast to account for morning-afternoon thunderstorms ahead of the cold front. Damaging
winds and perhaps a few tornadoes are the primary concerns.

..Darrow/Thornton.. 01/25/2026

$$

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ACUS01 KWNS 172014
SWODY1
SPC AC 172013

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0213 PM CST Tue Feb 17 2026

Valid 172000Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS COASTAL
CALIFORNIA AND PORTIONS OF NEBRASKA AND IOWA...

CORRECTED FOR NDFD COLOR FILL ISSUE

...SUMMARY...
Isolated strong thunderstorms will be possible across parts of the
West today through tonight. Isolated thunderstorms are also
anticipated across the Upper Midwest late this afternoon and
tonight.

...Eastern Nebraska and southwestern Iowa...
Near the base of a negative-tilt shortwave trough and a pronounced
100+ kt mid-level jet, strong ascent is expected to develop late
this afternoon amid a mixed and modestly moist air mass. Cool
mid-level temperatures and surface dewpoints in the 40s and 50s F
may allow a few hundred J/kg of buoyancy to develop. This
destabilization and strong ascent may support a fast-moving arc of
high-based showers/thunderstorms, particularly where surface
temperatures reach into the 60s and dewpoints hold above 40 F.

While buoyancy will be weak, dry low-levels and strong
dynamics/background flow could support efficient downward mixing of
momentum to the surface. Isolated severe/damaging gusts are possible
this afternoon and evening from parts of eastern NE into
west-central IA. Convection should weaken rapidly with eastward
extent

Elsewhere, isolated strong storms remain possible across portions of
the CA coast ahead of a strong secondary upper trough. This is most
likely overnight with a few damaging gusts or a brief tornado the
primary risks owing to very strong flow and modest inland moisture
advection. No changes were made to the outlook here, see the prior
discussion for more info.

..Lyons.. 02/17/2026

.PREV DISCUSSION... /ISSUED 1031 AM CST Tue Feb 17 2026/

...Synopsis...
Recent satellite imagery shows several disturbances across the
western CONUS, including a pair of low-amplitude shortwave troughs
within the belt of strong southwesterly flow extending from the
central Pacific into the central Plains and a deepening upper low
off the Pacific Northwest coast. Intense surface cyclogenesis is
anticipated ahead of the lead shortwave as it moves quickly
northeastward, with the resulting surface low forecast to move
across SD/NE, ending the period over southern MN. Evolution of this
surface low and parent shortwave, which will become increasingly
negatively tilted throughout the day and overnight, will result in
strong forcing for ascent from the Mid MO Valley into the Upper
Midwest this evening and overnight.

Farther west, the previously mentioned upper low is expected to drop
slowly southward as a strong jet (i.e. 100 kt at 500 mb) pivots
around its western and southern periphery. Very cold mid-level
temperatures and strong/persistent forcing for ascent will support
isolated thunderstorms along across much of the West coast
throughout the day and tonight.

...Coastal California...
Limited buoyancy is expected to develop along the near coastal areas
of CA as very cold mid-level temperatures (i.e. -25 to -30 deg C at
500 mb) associated with the upper low continue to advect into the
region. This buoyancy coupled with the strong forcing for ascent
could result in some deeper, more persistent updrafts across the
region today, both within the primary frontal band and any more
bowing line segments that may follow it. Given the robust deep layer
flow across the region, any deeper, more persistent updrafts could
result in some stronger, convectively augmented gusts. Additionally,
there appears to be enough low-level curvature to support a brief
tornado or two within the immediate coastal regions. Highest
potential for either hazards currently appears to be after 00Z in
the San Luis Obispo/Santa Barbara county areas.

...Upper Midwest...
Some low-level moisture return is anticipated across the region
ahead of the previously mentioned shortwave trough and associated
forcing for ascent. Even so, low-level moisture will still be
limited, with dewpoints likely remaining in the upper 40s to perhaps
low 50s. This is not expected to be enough moisture for surface
destabilization across most of the region, despite strong surface heating/boundary-layer mixing and steepening low-level lapse rates
in vicinity of the surface low/front. The only exception is across
far southeast SD and far northeast NE where a high-based storm or
two cannot be completely ruled out. Any that does develop could
produce an strong gust or two, although coverage will likely remain
less than 10%.

Across the Upper Midwest, capping may tend to largely prevail during
the day, with elevated thunderstorms becoming more probable
east-northeastward of IA into the MN/WI throughout the evening and
overnight. Instability does not appear strong enough to support
severe hail with this elevated activity.

$$

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