ACUS01 KWNS 210118
SWODY1
SPC AC 210116

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0816 PM CDT Fri Jun 20 2025

Valid 210100Z - 211200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NORTH DAKOTA AND MINNESOTA...

CORRECTED AREA MENTIONED IN FIRST SENTENCE OF THIRD PARAGRAPH OF
DISCUSSION

...SUMMARY...
A significant swath of severe winds is expected this evening and
tonight from the northern Plains eastward into the upper Mississippi
Valley.

...Northern Plains/Upper Mississippi Valley...
Water vapor imagery currently shows a shortwave trough moving
through the northern High Plains. Near the trough, a line of strong
to severe thunderstorms is ongoing across western North Dakota and
far northwestern South Dakota. As these storms move eastward across
the northern Plains this evening, a 60 to 70 knot mid-level jet will
move northeastward through the Dakotas. Lift associated the left
exit region of the jet, combined with a strongly unstable airmass
over the eastern Dakotas and western Minnesota will be favorable for
vigorous convective development. In response, the ongoing storms are
expected to grow upscale into a fast-moving severe MCS. The MCS is
forecast to track eastward across far northern South Dakota, North
Dakota and north-central Minnesota this evening.

At the surface, a 991 mb low will move northeastward across northern
South Dakota this evening. A tongue of very moist air with surface
dewpoints in the lower to mid 70s F will move northward into
southeastern North Dakota and central Minnesota this evening. Within
this moist airmass, strong instability is analyzed by the RAP with
MLCAPE in the 4000 to 5000 J/kg range. The ongoing line of severe
storms will move into this strong instability, and gradually
intensify over the next couple of hours. RAP forecast soundings
along the expected track of the MCS in southeastern North Dakota
this evening have moderate to strong deep-layer shear, long and
looped hodographs and steep mid-level lapse rates. This should be
favorable for supercells with large hail, wind damage and tornadoes.
A strong tornado may occur. Supercell development will be most
likely among cells that remain semi-discrete. However, a line is
expected to become more organized, which will make severe wind gusts
likely along its leading edge. Gusts above 80 mph will be possible
ahead of the more intense parts of the line. A Derecho may develop
across parts of the northern Plains and upper Mississippi Valley
this evening into tonight.

As the MCS moves into south-central North Dakota over the next few
hours, some short-term model forecasts develop discrete cells
further to the east near the moist axis in the vicinity of the
ND-SD-MN triple point. These storms are forecast to quickly expand
in coverage and move across northwest and north-central Minnesota,
ahead of the approaching MCS. These storms will likely be
supercellular, and be associated with large to very large hail, wind
damage and possible tornadoes.

A consolidation of the two areas of convection will likely take
place late this evening, with the severe MCS continuing to track
eastward across north-central Minnesota. A wind-damage swath is
expected as far east as northern Wisconsin and the western Upper
Peninsula of Michigan. Wind gusts of 85 to 105 mph will be possible
along parts of the MCS track.

...Southern Rockies/Central High Plains...
Water vapor imagery shows southwest flow over much of the
south-central U.S. A subtle shortwave trough appears to be located
in the southern Rockies, where convection has increased in coverage
over the last couple of hours. These storms will continue to move
northeastward into the High Plains this evening. Forecast soundings
from northeast New Mexico into northwest Kansas early this evening
have very steep low to mid-level lapse rates. This will likely
support a marginal threat for severe gusts, as the cells move into
the stronger instability over the High Plains.

..Broyles.. 06/21/2025

$$

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ACUS01 KWNS 211650
SWODY1
SPC AC 211649

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1149 AM CDT Sat Jun 21 2025

Valid 211630Z - 221200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER NORTHERN
PORTIONS OF NEW YORK AND VERMONT...

CORRECTED FOR SPELLING IN SUMMARY

...SUMMARY...
Thunderstorms associated with severe wind gusts and hail will be
possible tonight across New York and New England. Isolated severe
storms will also be possible across portions of the Great Lakes, the
northern High Plains and Middle Missouri Valley.

...Great Lakes...
Strong/intermittently severe thunderstorms continue across the
northern Lower Peninsula of Michigan this morning, associated with
the long-lived severe MCS that moved across the northern
Plains/upper Midwest Friday afternoon and night. Although the
immediate downstream environment is only slowly warming due to the
presence of mid/high-level clouds, some slow destabilization is
occurring. This will maintain at least some continued risk for a
strong/severe storm through early afternoon across northern Lower MI
and adjacent waters of Lake Huron.

Across the MI Upper Peninsula, a warm front is expected to sharpen
across this area, along with rising heights in the wake of the convectively-augmented vorticity maximum now moving through southern
Ontario. Heating of a very moist boundary layer will result in
strong to extreme instability (MLCAPE in excess of 3000 J/kg),
however the presence of a pronounced cap should suppress storms
during the afternoon. As a modest low-level jet strengthens this
evening, isolated elevated severe storms will be possible on the
immediate cool side of the front, within an environment supportive
of organized storms including supercells. Large hail and damaging
winds will be possible.

...NY into Western New England...
Thunderstorms moving across Lake Huron/southwestern Ontario at 16z
will continue east, and most morning CAM guidance suggests storms
will remain west of western NY. Of greater concern will be the
potential for storms to move into northern NY/western New England
late tonight ahead of a southeast-moving cold front, where modest destabilization and strong deep-layer shear will support storm
organization. Morning hi-res guidance supports a loosely organized
linear structure, and perhaps supercells with an attendant risk for
strong winds and severe hail late tonight. The Level 2/Slight Risk
has been expanded east into northern VT based on this expectation.

...Eastern MT into Western ND...
Isolated thunderstorms have weakened over eastern MT this morning,
with additional isolated redevelopment possible this afternoon and
tonight as ascent associated with minor perturbations within
southwest mid-level flow moves across the area. Modest instability
and strong deep-layer shear will support updraft organization and a
risk for severe hail and/or damaging gusts.

...Central NE/SD/ND into the Upper Midwest...
Surface low currently over central SD is expected to move little
this afternoon, with low-level moisture advection throughout the
warm sector east of this low. Air mass recovery/modification
following the overnight MCS is expected, and this will contribute to
a sharpening warm-frontal zone. Strong to extreme buoyancy (i.e.
MLCAPE greater from 3000 to 5000 J/kg) is expected by this evening
along this warm front from the ND/SD border vicinity eastward
through central MN into northern WI. Some low-level convergence is
anticipated in this region, but height rises will occur within the
large-scale environment. Additionally, warm mid-level temperatures
(16 to 17 deg C at 700 mb) are expected, capping the airmass to deep
convection this afternoon. Isolated thunderstorm development will be
possible mainly this evening as a low-level jet strengthens, with a
risk for severe wind and isolated hail.

..Bunting.. 06/21/2025

$$

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ACUS01 KWNS 220106
SWODY1
SPC AC 220104

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0804 PM CDT Sat Jun 21 2025

Valid 220100Z - 221200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NEW YORK AND NEW ENGLAND...

CORRECTED FOR FLIPPED THUNDER LINE IN SOUTHEAST

...SUMMARY...
Thunderstorms associated with severe wind gusts and hail will be
possible tonight across New York and New England. Isolated severe
storms will also be possible across parts of the Great Lakes and the
central to northern Plains.

...Northeast/New York/Great Lakes...
Latest water vapor imagery has a belt of strong anticyclonic flow
located from the upper Mississippi Valley into the Great Lakes and
Northeast. A ridge-riding mid-level shortwave trough is located over
Ontario. At the surface, a moist airmass is in place from New York
into western New England, where surface dewpoints are in the lower
to mid 60s F. The low-level moisture will contribute to continued destabilization across the region, in the form of elevated
instability, this evening into tonight. As the shortwave trough
moves southeastward toward the Northeast, low-level flow will
markedly strengthen. In response, convective coverage is expected to
increase, and a line of thunderstorms appears likely to develop late
this evening. This line is forecast to move southeastward across New
York and western New England from late evening into the overnight
period.

Overnight, RAP forecast soundings ahead of the line in northern New
York have a low-level temperature inversion, with MUCAPE in the 1500
to 2000 J/kg range. Effective shear is forecast to be around 40
knots. This should be favorable for a severe threat. Although much
of the line could be elevated, isolated large hail and severe gusts
will still be possible, mainly with the more intense component of
the line. The line is expected to move through the western New
England and the Hudson River Valley late tonight, approaching
southern New England toward 12Z.

...Central Plains...
Southwest mid-level flow is in place across much of the central
Plains early this evening. At the surface, a moist airmass is
located over much of the High Plains, with surface dewpoints mostly
in the 60s F. In response to low-level warm advection, isolated to
scattered thunderstorms will likely develop along the western edge
of this moist airmass. This convection is expected to move
northeastward across Nebraska and southeastern South Dakota this
evening. In addition to moderate instability, mid-level lapse rates
are very steep. This, combined with moderate deep-layer shear, will
likely support a marginal severe threat. Hail and isolated severe
gusts will be possible.

...Northern High Plains...
A mid-level trough, evident on water vapor imagery, will move
northeastward into the northern High Plains tonight. Ahead of the
trough, a post-frontal airmass is in place with the western edge of
a moist airmass located over the western Dakotas. As large-scale
ascent increases across the northern High Plains later tonight,
scattered thunderstorm development is expected. These storms will
move northeastward across eastern Montana and western North Dakota,
mainly after midnight. Weak to moderate instability, combined with
steep lapse rates and moderate deep-layer shear should support a
marginal severe threat. Hail and a few severe gusts will be
possible.

..Broyles.. 06/22/2025

$$

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ACUS01 KWNS 251627
SWODY1
SPC AC 251625

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1125 AM CDT Wed Jun 25 2025

Valid 251630Z - 261200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHWEST NORTH CAROLINA...CENTRAL AND NORTHERN SOUTH CAROLINA...AND
EASTERN GEORGIA....

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST
COLORADO INTO PARTS OF IOWA AND MINNESOTA....

CORRECTED FOR NDFD GRID ERROR IN SC

...SUMMARY...
Severe wind gusts are possible from parts of the Carolinas into the
Southeast, with widely scattered strong to severe storms possible
from the northern High Plains eastward to the Mid Atlantic.

...Southeast US...
An unusually favorable thermodynamic pattern has evolved across the
southeast US today, with very steep mid-level lapse rates, cool
temperatures aloft, and strong daytime heating. Surface dewpoints
in the 70s will yield afternoon MLCAPE values over 3500 J/kg.

Large scale forcing is weak, suggesting convective initiation will
be poorly focused. However, most 12z CAM solutions show several
clusters of storms through the afternoon spreading southward from NC
into SC and eastern GA. Vertical shear is rather weak, suggesting
storms will be rather disorganized. However, there is a conditional
risk for an active day across the ENH risk, with considerable
coverage of damaging wind reports possible. As storms spread
southwestward this evening across GA, the risk of locally damaging
wind gusts will continue.

...NE/IA/MN...
Visible satellite imagery shows a developing differential heating
zone extending from south-central NE into central IA. Full sun to
the south of this zone will lead to strong instability and scattered
afternoon thunderstorm development. A band of 30-40 knot
southwesterly flow aloft atop this zone, coupled with strengthening
southerly low-level winds, will encourage organized/bowing clusters
of storms capable of damaging winds and some hail. A tornado or two
cannot be ruled out.

...CO/KS...
Thunderstorms will once again develop off the higher terrain of
CO/WY this afternoon and spread into the Plains. Model guidance
suggests steep low-level lapse rates and sufficient CAPE for severe
wind potential as these storms track toward northwest KS/southwest
NE by early evening.

...OH/WV...
Hot and humid conditions are present today across much of southern
OH into northern WV. Visible satellite imagery shows a developing
CU field, which may result in scattered slow-moving afternoon
thunderstorms. Winds aloft are rather weak, but the strongest cells
in this corridor may be capable of locally damaging wind gusts.

..Hart.. 06/25/2025

$$

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