ACUS01 KWNS 122014
SWODY1
SPC AC 122012

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0312 PM CDT Tue Aug 12 2025

Valid 122000Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
GREAT LAKES REGION...

CORRECTED FOR NDFD

...SUMMARY...
Strong to locally severe thunderstorms are possible over parts of
the Great Lakes/Midwest this afternoon with both damaging winds and
hail possible.

...20Z Update...
Given the weak mid/upper-level flow, the potential for organized
severe wind gusts appears very limited in southeast
Arizona/southwest New Mexico. Steep low-level lapse rates may still
support strong/gusty outflow however. Elsewhere only minor update
the general thunderstorm area were made. See the previous discussion
for additional details.

..Wendt.. 08/12/2025

.PREV DISCUSSION... /ISSUED 1128 AM CDT Tue Aug 12 2025/

...Great Lakes/Midwest...
Midday satellite/radar composite show a weakened thunderstorm band
moving east-northeast across the eastern part of Lower MI. Surface
analysis indicates rain-cooled air north of a gust front/outflow
that has become draped from southeast Lower MI into the Michiana
region. Heating south of this boundary has resulted in temperatures
warming through the mid-upper 80s with dewpoints in the lower 70s.
Additional storms will probably develop along the trailing outflow
and gradually move east-northeast with the mean wind. Considerably
weaker deep-layer shear is present across the eastern part of the
Corn Belt into the Lower MI vicinity compared to farther north over
the U.P. of MI in closer proximity to a shortwave trough.
Nonetheless, scattered thunderstorms will gradually develop within a moist/destabilizing airmass and pose a risk for isolated strong to
perhaps locally severe/damaging gusts this afternoon.

Farther north in WI into the U.P. of MI, a weak cold front will move
into the region later this afternoon. Model guidance shows widely
scattered storms developing as filtered sunshine leads to a
destabilizing boundary layer. A few stronger thunderstorms are
possible and could yield a localized risk for marginally severe hail
and damaging gusts during the mid afternoon to early evening period.

...Southeast AZ/southwest NM...
Strong heating should result in widely scattered thunderstorms
developing near terrain-favored areas. Weak shear will result in
disorganized storms, but the development of very steep surface to
500-mb lapse rates will promote strong evaporative cooling with the
more intense downdrafts. Isolated severe gusts are possible.

$$

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ACUS01 KWNS 241311
SWODY1
SPC AC 241310

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0810 AM CDT Sun Aug 24 2025

Valid 241300Z - 251200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTH-CENTRAL PLAINS AND NORTHEAST...

CORRECTED FOR GRAPHICS

...SUMMARY...
A few severe storms are expected this afternoon and evening across
the south-central High Plains spanning eastern Colorado into western
Oklahoma. Scattered strong to severe storms are also possible across
portions of Pennsylvania and New York.

...South-central High Plains..
Within an amplified upper flow regime, a moderately strong belt of northwesterly winds aloft will exist over the region, with one or
more low-amplitude ridge-peripheral disturbances expected to pivot
eastward later today over the central Rockies. A pronounced surface
anticyclone will settle into the northern Plains, forcing the
leading edge of more continental air into the southern Plains by the
end of the period. A corridor of low-level warm advection will
become established from southern Wyoming into western Oklahoma
coincident with the northwest/southeast-oriented front.

Widely scattered generally non-severe elevated storms will probably
persist this morning across western Kansas, with some potential that
the storms may help focus some renewed/increasing convective
potential later today from southwest Kansas into western
Oklahoma/eastern Texas Panhandle. Aided by increasing low-level
upslope flow, other potentially severe storms are expected to
develop across the Colorado Front Range vicinity by late afternoon
and drift southeastward through early/mid-evening. A couple of
supercells will initially be possible, before storms tend to cluster
by evening. Large hail and damaging winds are the primary concerns
regionally, although current thinking is that overall potential
should remain relatively isolated.

...Northeast including New York/Pennsylvania...
A prominent upper-level trough over Ontario/Quebec and Great Lakes
will shift eastward today. An associated surface front is forecast
to advance into western portions of New York/Pennsylvania by early
afternoon. Modest boundary-layer heating is expected to aid
destabilization ahead of the front and convective temperatures
should be breached by around 20-21z; although, deep-layer lapse
rates are not expected to be particularly steep (0-6 km values
around 6.5 C/km). These storms could generate locally strong winds,
and perhaps some hail, with the main risk from mid-afternoon into
early evening.

..Guyer/Kerr.. 08/24/2025

$$

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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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