WW 424 SEVERE TSTM MN WI LM 302020Z - 010300Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 424
NWS Storm Prediction Center Norman OK
320 PM CDT Tue Jun 30 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Southeast Minnesota
Wisconsin
Lake Michigan
* Effective this Tuesday afternoon and evening from 320 PM until
1000 PM CDT.
* Primary threats include...
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
Scattered damaging wind gusts to 70 mph possible
A tornado or two possible
SUMMARY...Scattered strong to severe thunderstorms are expected to
intensify, generally near where storms moved through the region
earlier day. This renewed development may produce large hail and
damaging winds into this evening within a very moist and unstable
environment.
The severe thunderstorm watch area is approximately along and 45
statute miles north and south of a line from 40 miles north
northwest of Rochester MN to 45 miles northeast of Green Bay WI. For
a complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU4).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 423...
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 600. Mean storm motion vector
24025.
...Guyer
WW 423 SEVERE TSTM MA NY VT LO 301715Z - 010000Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 423
NWS Storm Prediction Center Norman OK
115 PM EDT Tue Jun 30 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Far western Massachusetts
Central and Eastern New York
Far southern Vermont
Lake Ontario
* Effective this Tuesday afternoon and evening from 115 PM until
800 PM EDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph likely
Isolated large hail events to 1.5 inches in diameter possible
A tornado or two possible
SUMMARY...A well-organized and fast-moving cluster of storms will
continue southeastward this afternoon with a primary concern for
damaging winds as storms progress southeastward. Additional
peripheral development is also possible this afternoon across other
parts of the nearby region within an unstable air mass.
The severe thunderstorm watch area is approximately along and 70
statute miles east and west of a line from 25 miles north northwest
of Watertown NY to 55 miles east of Binghamton NY. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU3).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 600. Mean storm motion vector
31040.
...Guyer
WW 0424 Status Updates
STATUS REPORT ON WW 424
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..MEAD..06/30/26
ATTN...WFO...ARX...MPX...GRB...
STATUS REPORT FOR WS 424
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MNC039-049-109-157-169-302140-
MN
. MINNESOTA COUNTIES INCLUDED ARE
DODGE GOODHUE OLMSTED
WABASHA WINONA
WIC009-011-017-019-029-033-035-053-061-067-069-073-075-078-083-
087-091-093-097-115-119-121-135-141-302140-
WI
. WISCONSIN COUNTIES INCLUDED ARE
BROWN BUFFALO CHIPPEWA
CLARK DOOR DUNN
EAU CLAIRE JACKSON KEWAUNEE
LANGLADE LINCOLN MARATHON
MARINETTE MENOMINEE OCONTO
OUTAGAMIE PEPIN PIERCE
PORTAGE SHAWANO TAYLOR
TREMPEALEAU WAUPACA WOOD
LMZ521-522-542-302140-
WW 0423 Status Updates
STATUS REPORT ON WW 423
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 E ROC TO
15 NE SYR TO 30 W GFL.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1401
..MEAD..06/30/26
ATTN...WFO...ALY...BGM...BUF...BTV...
STATUS REPORT FOR WS 423
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MAC003-302140-
MA
. MASSACHUSETTS COUNTIES INCLUDED ARE
BERKSHIRE
NYC001-007-011-017-021-023-025-035-039-043-053-057-065-067-077-
083-091-093-095-099-107-109-115-117-302140-
NY
. NEW YORK COUNTIES INCLUDED ARE
ALBANY BROOME CAYUGA
CHENANGO COLUMBIA CORTLAND
DELAWARE FULTON GREENE
HERKIMER MADISON MONTGOMERY
ONEIDA ONONDAGA OTSEGO
RENSSELAER SARATOGA SCHENECTADY
SCHOHARIE SENECA TIOGA
TOMPKINS WASHINGTON WAYNE
WW 0422 Status Updates
STATUS REPORT ON WW 422
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 SSE GRB
TO 20 NNE GRB TO 50 NW MBL.
..MEAD..06/30/26
ATTN...WFO...MQT...GRB...
STATUS REPORT FOR WS 422
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
WIC009-061-301740-
WI
. WISCONSIN COUNTIES INCLUDED ARE
BROWN KEWAUNEE
LMZ522-301740-
CW
. ADJACENT COASTAL WATERS INCLUDED ARE
GREEN BAY SOUTH OF LINE FROM OCONTO WI TO LITTLE STURGEON BAY WI
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
MD 1401 CONCERNING SEVERE THUNDERSTORM WATCH 423... FOR SOUTH-CENTRAL AND SOUTHEAST NEW YORK INTO WESTERN MASSACHUSETTS AND NORTHWEST CONNECTICUT
Mesoscale Discussion 1401
NWS Storm Prediction Center Norman OK
0332 PM CDT Tue Jun 30 2026
Areas affected...South-central and Southeast New York into Western
Massachusetts and Northwest Connecticut
Concerning...Severe Thunderstorm Watch 423...
Valid 302032Z - 302230Z
The severe weather threat for Severe Thunderstorm Watch 423
continues.
SUMMARY...The threat for damaging winds and large hail continues
across southern parts of the watch area. That threat may develop
south of the current watch area by 22Z, requiring either an areal
extension of the existing watch or a new downstream watch.
DISCUSSION...Renewed thunderstorm development has recently occurred
along the legacy cold pool across portions of Saratoga, Schenectady,
and Montgomery Counties with more discrete storms persisting into
Otsego County as of 20:20Z. A slight increase in inbound base
velocities has been noted by the KENX radar, and given these trends,
damaging wind potential may increase over the next hour with the
re-strengthening bowing system.
Assuming that scenario unfolds, the severe weather threat would
potentially move out of the watch area by 22Z, requiring either a
watch extension or new watch.
..Mead.. 06/30/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OKX...ALY...BGM...
LAT...LON 42647686 42877689 43257484 43297397 42847337 41907311
41627378 41637506 41757578 42197661 42647686
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
MD 1400 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTHEAST MINNESOTA INTO CENTRAL AND NORTHERN WISCONSIN
Mesoscale Discussion 1400
NWS Storm Prediction Center Norman OK
0251 PM CDT Tue Jun 30 2026
Areas affected...Southeast Minnesota into Central and Northern
Wisconsin
Concerning...Severe potential...Watch possible
Valid 301951Z - 302215Z
Probability of Watch Issuance...60 percent
SUMMARY...A conditional risk for severe thunderstorms capable of
mainly large hail and damaging winds appears to be materializing
across the discussion area this afternoon. Convective trends are
being monitored for a possible Severe Thunderstorm Watch.
DISCUSSION...Recent trends in visible satellite indicate a deepening
cumulus field along the nose of richer low-level moisture return
from the Rochester, MN, area into central WI, near Marshfield. The
shallow near-surface moisture profile observed by the 18z GRB
sounding is likely not representative of the boundary-layer
structure in the vicinity of the growing cumulus, where latest
objective analysis indicates MLCAPE of 3500-4500 J/kg with little to
no remaining convective inhibition.
In the absence of appreciable forcing for ascent and discernible
low-level boundaries, it remains unclear whether any storms that
initiate will become sustained and rooted within the strongly
unstable boundary layer. On the condition that storm initiation and
sustenance occur, the 18z GRB sounding sampled sufficient vertical
shear for supercells with the initial hazard being large hail.
Damaging wind potential would likely increase by late afternoon into
evening as storms coalesce along a common cold pool.
..Mead/Guyer.. 06/30/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GRB...DLH...ARX...MPX...
LAT...LON 45908981 45648899 44748888 44468950 44339009 44209072
44039244 44709263 45369211 45908981
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
MD 1399 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR NORTHEAST NEW MEXICO...SOUTHEAST COLORADO...SOUTHWEST KANSAS...THE WESTERN OKLAHOMA PANHANDLE...AND FAR NORTHWEST TEXAS PANHANDLE
Mesoscale Discussion 1399
NWS Storm Prediction Center Norman OK
0243 PM CDT Tue Jun 30 2026
Areas affected...northeast New Mexico...southeast
Colorado...southwest Kansas...the western Oklahoma Panhandle...and
far northwest Texas Panhandle
Concerning...Severe potential...Watch possible
Valid 301943Z - 302145Z
Probability of Watch Issuance...60 percent
SUMMARY...The severe weather threat will increase this
afternoon/evening across portions of the southern High Plains.
DISCUSSION...A storm has developed in Union County, New Mexico this
afternoon where 50s dewpoints have backed up into the higher
terrain. Visible satellite imagery also suggests additional
development may occur north of this storm near the Raton Mesa. SPC
mesoanalysis shows around 35 to 40 knots of effective shear across
the area. The PUX VWP is sampling around 40 to 45 knots at 4-5km
which would support the 35 to 40 knot shear values farther
southeast. This shear, combined with weak to moderate instability
will support the potential for supercell structures and some hail
threat. Through time, expect storms to grow upscale as they move
east into a more unstable airmass with an increasing severe wind
threat into the evening.
..Bentley/Guyer.. 06/30/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DDC...GLD...AMA...PUB...ABQ...
LAT...LON 36150353 36710369 36940373 37910305 38590251 38670171
38400140 37610143 36490221 36130297 36150353
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1150 AM CDT Tue Jun 30 2026
Valid 301630Z - 011200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE
CENTRAL HIGH PLAINS...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
PLAINS...GREAT LAKES AND NORTHEAST...
...SUMMARY...
Scattered severe thunderstorms are expected across parts of the
central High Plains, with severe wind gusts (60 to 85 mph) being the
primary hazard during the late afternoon and evening. Other severe
thunderstorms are expected across the Great Lakes and Northeast, as
well as broader parts of the central Plains to middle Missouri
Valley.
...Southern/Central Plains...
Scattered thunderstorms are forecast later this afternoon over the
High Plains on the western rim of richer low-level moisture and
strong insolation. Model guidance shows considerable erosion of the
capping layer by mid-afternoon with MLCAPE ranging from 1500 J/kg
over the Texas South Plains to 3500 J/kg over western Kansas.
Initially higher-based convection will gradually move east into
richer moisture and promote larger thunderstorm cores and increased
potential for storm clusters to develop. Large hail will be possible
with any initial supercell activity (i.e., most probable from the
northern Texas Panhandle into Kansas; 25-40 kt effective shear).
However, very steep surface to 300-mb lapse rates will favor strong
evaporative cooling with the more intense cores. Ample deep-layer
shear will exist for organized storms, but veering/backing of flow
with height will aid in storm outflow aggregating as linear clusters
become the primary storm mode with time. These organized but linear
clusters will likely be efficient in promoting severe wind gusts
(60-85 mph) during the early evening, coincident with a
strengthening LLJ and WAA before this threat wanes by late evening.
Weaker deep-layer shear farther south in the southern High Plains
will likely limit both storm organization and overall coverage of
the wind risk.
Later into this evening, confidence has increased in mainly
nocturnal development in a post-frontal environment, that will
probably have its genesis by early evening in the vicinity of
northeast Colorado/southwest Nebraska. These storms will likely
increase/expand northeastward tonight with large hail and damaging
wind potential, which could actually increase and become somewhat
more prominent overnight across northern Nebraska/southeast South
Dakota and neighboring Siouxland as storms cluster and as the warm
front quickly shifts northward regionally.
...Upper Midwest/Great Lakes...
A few strong storms could occur early this afternoon across northern
Michigan, but primary concern is the potential for redevelopment
later today, potentially focused along a zone of modifying
outflow/differential heating, with robust instability to the south.
Although the degree of mid-level capping is a key uncertainty, where
storms do redevelop, ample tropospheric flow will support organized
storms, including supercells capable primarily of a hail/wind risk
and perhaps a tornado. Storms will likely become more probable and
increase this evening with at least some hail and wind potential
continuing tonight.
...Northeast States...
A cluster of storms over southeast Ontario at midday will likely
continue to progress southeastward over Lake Ontario toward northern
New York today. See Mesoscale Discussion 1396 for additional
details. These storms coincide with a 30-40 kt belt of northwesterly
mid-level flow that resides on the immediate periphery of a
gradually building upper-level ridge and associated elevated mixed
layer. Residual cloud cover, via overnight/pre-dawn decayed
convection, casts a bit of uncertainty regarding boundary layer
destabilization over portions of this region, especially with
northeastward extent. Nonetheless, increasing storm
coverage/intensity is expected this afternoon including
clusters/bowing segments and possibly a few supercells.
...Southeast...
Located to the south of an upper high centered over the Tennessee
Valley, a very moist air mass is present across much of the region.
Strong heating will yield moderate buoyancy by early afternoon.
Forecast soundings depict around 20-kt effective shear which will
aid in minor multicellular organization. Localized 50-60 mph gusts
capable of isolated wind damage will accompany the stronger storms.
..Guyer/Bentley.. 06/30/2026
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0257 PM CDT Tue Jun 30 2026
Valid 302000Z - 011200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF WESTERN KANSAS...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN
HIGH PLAINS TO THE GREAT LAKES AND PARTS OF NEW ENGLAND...
...SUMMARY...
Scattered severe thunderstorms are still expected across parts of
the central High Plains, with severe wind gusts (60 to 85 mph) being
the primary hazard during the late afternoon and evening. Other
severe thunderstorms are still expected across the Great Lakes and
Northeast, as well as broader parts of the central Plains to middle
Missouri Valley.
...20Z Update...
The most noteworthy change made to the Day 1 Outlook for the 20Z
update was to join the two Slight Risk areas, driven by wind
probabilities, across the Plains to the Great Lakes. Furthermore,
the CIG1 area was expanded northeast into the Upper MS Valley.
Guidance consensus has consistently depicted a persistent region of
likely cold-pool-driven convection propagating around the upper
ridge periphery, from the central Plains this evening, toward the
Great Lakes through 12Z tomorrow morning. Uncertainty remains
regarding the overall morphology and evolution of this convection,
hence the constraining of severe wind probabilities to Category
2/Slight risk. However, overnight storms will traverse an elongated
axis of strong buoyancy, characterized by 8-9 C/km 700-500 mb lapse
rates atop 70+ F surface dewpoints (per 18Z OAX and GRB observed
soundings), along with forecast 30-40 kts of effective bulk shear.
As such, if more organized storm modes (particularly bow echoes) can
develop tonight, a couple of 75+ mph gusts could occur.
Otherwise, the previous forecast remains on track, with mainly minor
changes made to thunder and severe probabilities to reflect the
consensus among the latest observations and numerical guidance.
..Squitieri.. 06/30/2026
.PREV DISCUSSION... /ISSUED 1150 AM CDT Tue Jun 30 2026/
...Southern/Central Plains...
Scattered thunderstorms are forecast later this afternoon over the
High Plains on the western rim of richer low-level moisture and
strong insolation. Model guidance shows considerable erosion of the
capping layer by mid-afternoon with MLCAPE ranging from 1500 J/kg
over the Texas South Plains to 3500 J/kg over western Kansas.
Initially higher-based convection will gradually move east into
richer moisture and promote larger thunderstorm cores and increased
potential for storm clusters to develop. Large hail will be possible
with any initial supercell activity (i.e., most probable from the
northern Texas Panhandle into Kansas; 25-40 kt effective shear).
However, very steep surface to 300-mb lapse rates will favor strong
evaporative cooling with the more intense cores. Ample deep-layer
shear will exist for organized storms, but veering/backing of flow
with height will aid in storm outflow aggregating as linear clusters
become the primary storm mode with time. These organized but linear
clusters will likely be efficient in promoting severe wind gusts
(60-85 mph) during the early evening, coincident with a
strengthening LLJ and WAA before this threat wanes by late evening.
Weaker deep-layer shear farther south in the southern High Plains
will likely limit both storm organization and overall coverage of
the wind risk.
Later into this evening, confidence has increased in mainly
nocturnal development in a post-frontal environment, that will
probably have its genesis by early evening in the vicinity of
northeast Colorado/southwest Nebraska. These storms will likely
increase/expand northeastward tonight with large hail and damaging
wind potential, which could actually increase and become somewhat
more prominent overnight across northern Nebraska/southeast South
Dakota and neighboring Siouxland as storms cluster and as the warm
front quickly shifts northward regionally.
...Upper Midwest/Great Lakes...
A few strong storms could occur early this afternoon across northern
Michigan, but primary concern is the potential for redevelopment
later today, potentially focused along a zone of modifying
outflow/differential heating, with robust instability to the south.
Although the degree of mid-level capping is a key uncertainty, where
storms do redevelop, ample tropospheric flow will support organized
storms, including supercells capable primarily of a hail/wind risk
and perhaps a tornado. Storms will likely become more probable and
increase this evening with at least some hail and wind potential
continuing tonight.
...Northeast States...
A cluster of storms over southeast Ontario at midday will likely
continue to progress southeastward over Lake Ontario toward northern
New York today. See Mesoscale Discussion 1396 for additional
details. These storms coincide with a 30-40 kt belt of northwesterly
mid-level flow that resides on the immediate periphery of a
gradually building upper-level ridge and associated elevated mixed
layer. Residual cloud cover, via overnight/pre-dawn decayed
convection, casts a bit of uncertainty regarding boundary layer
destabilization over portions of this region, especially with
northeastward extent. Nonetheless, increasing storm
coverage/intensity is expected this afternoon including
clusters/bowing segments and possibly a few supercells.
...Southeast...
Located to the south of an upper high centered over the Tennessee
Valley, a very moist air mass is present across much of the region.
Strong heating will yield moderate buoyancy by early afternoon.
Forecast soundings depict around 20-kt effective shear which will
aid in minor multicellular organization. Localized 50-60 mph gusts
capable of isolated wind damage will accompany the stronger storms.
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1245 PM CDT Tue Jun 30 2026
Valid 011200Z - 021200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN
MINNESOTA INTO PARTS OF NORTHERN/CENTRAL WISCONSIN AND NORTHERN
LOWER MICHIGAN...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHEAST AND THE CENTRAL HIGH PLAINS...
...SUMMARY...
Scattered severe storms will again be possible across the Upper
Midwest/Great Lakes Wednesday into Wednesday night. Damaging wind
gusts (some to 80 mph) are expected, in addition to isolated large
to very large hail and a few tornadoes. Additional severe storms,
posing mainly a damaging wind risk, are possible across parts of the
Northeast and the central High Plains.
...Synopsis...
An upper shortwave trough will move across the Upper Midwest and
Great Lakes Wednesday, eventually flattening the upper ridge over
the Northeast late in the period. With this shortwave, a band of
enhanced mid/upper-level southwesterly flow will overspread the
Upper Midwest and Great Lakes. A quasi-stationary surface boundary
will extend from eastern SD northeast toward Lake Superior. Along
and south of this boundary will be a focus for potentially multiple
rounds of severe thunderstorms Wednesday and Wednesday night across
the Upper MS Valley/Great Lakes. Additional strong to severe storms
are expected across the Northeast, the South, the central/southern
High Plains, and portions of Montana.
...Upper Midwest/Great Lakes vicinity...
A somewhat similar pattern compared to previous days is expected on
Wednesday. However, the upper trough moving across the region will
be a bit strong as the upper low over the Canadian Prairies finally
becomes more progressive. A belt of 50-70 kt southwesterly flow
between 700-500 mb is noted in various forecast guidance, supporting
40+ kt effective shear magnitudes and supercell wind profiles. The
boundary layer continues to be very moist, with dewpoints in the mid
60s to mid 70s present beneath modestly steep midlevel lapse rates,
resulting in strong to extreme buoyancy.
Convection may be ongoing early in the period near southern MN,
though where exactly these storms are located depends on convective
evolution in the current Day 1/Tuesday period. This convection could
be severe with a risk for damaging winds and hail. It is possible
this activity could develop east/northeast along the surface
boundary and intensify through the morning/afternoon as it moves
across WI and pose a severe risk of damaging winds. Or, it could
weaken and additional severe storms could develop near the surface
boundary across WI/northern MI during the day. Another round of
convection is expected to develop during the evening across southern
MN. This activity could initially be supercells, with an
accompanying all-hazards severe risk. However, storms are expected
to quickly grow upscale into a bowing MCS, moving east/northeast
through the nighttime hours across WI/MI.
While exact convective evolution is uncertain, it does appear that
more than one round of severe storms is possible across the region
on Wednesday. Swaths of damaging winds (some to near 80 mph) appear
likely. Isolated large to very large hail also is possible,
especially if any supercell storm mode can persist. A few tornadoes
also will be possible.
...Northeast...
Enhanced west/northwesterly flow will continue on Wednesday across
the region. Another day of very moist and hot conditions is
expected, supporting a corridor of strong to extreme buoyancy.
Thunderstorm clusters posing a damaging wind and isolated hail risk
will be possible during the afternoon. More organized convection is
expected to sweep across the region during the evening/overnight
hours as the upper ridge breaks down with the approach of an upper
shortwave trough over the Upper Great Lakes. Organized convection
over Ontario/Quebec will likely move east/southeast during the
nighttime hours and pose a risk for damaging wind gusts.
...Central/Southern High Plains...
Convection is expected to develop along a surface dryline Wednesday
afternoon/evening. Vertically veering wind profiles will increase
southwesterly flow aloft will support transient supercell structures
initially. Forecast hodographs show 25 kt effective shear magnitudes
amid long/straight hodographs. Strong/severe outflow winds will be
possible, along with isolated hail. Sufficient clustering/outflow
consolidation may occur, supporting greater wind potential,
particularly across the western KS vicinity.
...Lower MS/TN Valleys vicinity...
A similar pattern will exist across the region on Wednesday on the
southern periphery of the upper anticyclone over the eastern U.S.
Forecast guidance once again depicts modest midlevel
east/northeasterly flow providing support for 20-25 kt effective
shear magnitudes. Thunderstorm clusters will develop during the
afternoon within the theta-e axis. The very moist and abundantly
unstable airmass will support a wet microburst risk. If sufficient
clustering occurs, some potential for forward propagating convection
will exist, which could increase damaging wind potential through
early evening.
...MT...
An upper trough over the western U.S. will bring modestly enhanced
southwesterly mid/upper flow across portions of the northern Rockies
Wednesday afternoon/evening. A plume of steeper midlevel lapse rates
will gradually spread northeast from the Great Basin into parts of
southwest/central MT atop modest low-level moisture. This will
support 500-1000 J/kg MLCAPE. Steep low-level lapse rates and
sufficient vertical shear for organized cells/clusters will result
in a risk for isolated strong to severe wind gusts.
..Leitman.. 06/30/2026
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0211 PM CDT Tue Jun 30 2026
Valid 021200Z - 031200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHERN PLAINS TO THE GREAT LAKES...
...SUMMARY...
Strong to severe storms will be possible from the northern Plains
into the Midwest and Great Lakes regions on Thursday. Isolated
strong to severe storms may also occur in the Tennessee
Valley/Southeast as well as parts of the Northeast.
...Northern High Plains to the Upper Midwest...
Upper ridging will build over the northern Plains on Thursday,
though temperatures aloft will remain fairly cool at around -12 to
-10 C at 500 mb. A broad belt of enhanced west/southwesterly
mid/upper-level flow will overspread the region, and a southerly
low-level jet is forecast to intensify across the central into
northern Plains overnight. At the surface, a quasi-stationary
boundary will arc from northern North Dakota into central MN/WI
during the afternoon. Meanwhile, a surface trough will extend
southward along the High Plains. South/southeasterly low-level flow
will maintain a very moist airmass across parts of the central
Plains into the Upper Midwest, while transporting low 60s dewpoints
northwest to near the ND/SD/MT/WY border. A broad swath of moderate
to strong instability will materialize across the warm sector
buffered by these two surface boundaries.
Convection may be ongoing where from the Mid-MO Valley to Upper
Midwest Thursday morning, though this is uncertain. Additional
storms are expected during the afternoon along the surface
boundaries across the northern High Plains southeastward into
MN/IA/WI. Forecast soundings suggest supercell will be possible,
with an accompanying all-hazards risk possible, at least initially.
With time, convection in the High Plains should grow upscale and
track southeast along the surface boundary and in the vicinity of
the terminus of the increasing low-level jet. This activity will
pose a risk of damaging wind swaths. Additional clustering/MCS
development is possible near the surface boundary across MN/WI and
perhaps into Lower MI during the evening/overnight.
...TN Valley Vicinity...
Another modest midlevel shortwave impulse will likely migrate
through easterly flow on the southern periphery of the upper ridge
over the eastern U.S. A very moist and strongly unstable airmass
will once again support a wet microburst risk, with some potential
for sufficient clustering to result in forward propagating
convection. Isolated to widely scattered damaging wind gusts are
expected.
...Northeast...
A weak cold front will approach the region Thursday night as a
surface low over Quebec lifts northeast. Ahead of this feature a
very moist, hot, and unstable airmass will be in place. Minor height
falls throughout the day and increasing westerly flow aloft will
support at least isolated thunderstorm development. Strong/locally
damaging gusts and hail will be possible with the strongest storms.
..Leitman.. 06/30/2026
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1153 AM CDT Tue Jun 30 2026
Valid 301700Z - 011200Z
...CRITICAL FIRE WEATHER AREA FOR NORTHEAST ARIZONA...EASTERN
UTAH...WESTERN COLORADO...AND FAR NORTHWEST NEW MEXICO...
...Morning Update...
The forecast remains on track. Across portions of the risk areas,
poor overnight humidity recoveries contributed to an extended
burning period, with some fires remaining quite active into the
early morning hours. Current surface observations depict widespread
RH values of less than 20%, including some parts of central-northern
NM and south-central CO where dry thunderstorms may develop this
afternoon. In addition, a localized dry thunderstorm risk exists
across far northeastern Utah into northwestern CO where a shortwave
trough will pass over the Uinta Basin this afternoon. This feature
will provide sufficient lift to an antecedent moist airmass
available in western UT, encouraging the development of a few
thunderstorms. The UT higher terrain currently divides a moist
airmass to the west and a dry airmass to the east, where
precipitation efficiency is less likely. Any storms that develop may
push eastward across the Uinta Basin between 21-03z before
diminishing late this evening. A lightning ignition cannot be ruled
out, especially where dry fuels exist, and gusty/erratic outflow
winds may impact ongoing fires or new ignitions. See the previous
discussion for more information.
..Elizalde-Garcia.. 06/30/2026
.PREV DISCUSSION... /ISSUED 1247 AM CDT Tue Jun 30 2026/
...Synopsis...
Broad upper-level troughing will remain over the West with a
shortwave moving from the southern Great Basin into the central
Rockies. Southwest mid-level flow of 30-50 knots will overspread the
greater Four Corners region as downslope flow and lee troughing are
expected again on the central/southern High Plains.
...Greater Four Corners Region...
Stronger southwest flow aloft will mix to the surface across the
greater Four Corners region, resulting in southwest sustained winds
of 15-25 mph amid minimum RH of 5-15%. Northeast Arizona through
eastern Utah, western Colorado, and into far northwest New Mexico
will have critical fire weather conditions for several hours, likely
beginning by late morning and continuing into the evening. Locally
extremely critical conditions are possible (5-20% probabilities) in
eastern Utah and western Colorado during the afternoon, while
locally critical fire weather conditions are likely along/east of
the Sangre de Cristo Mountains into the Front Range. Elevated
conditions are expected in portions of eastern Colorado and
northeast New Mexico amid southerly winds of 15-20 mph and minimum
RH of 15-20%, but the duration and magnitude are likely to be
limited by thunderstorms in the afternoon and evening.
Isolated mixed wet/dry thunderstorms are likely across portions of
north-central New Mexico into south-central Colorado. Wetter storms
and greater storm coverage are likely to the south and east of the
IsoDryT area. Deep pyroconvection is possible on active large fires
in the vicinity of the overlap of elevated/locally critical fire
weather conditions and the IsoDryT area.
...Please see www.spc.noaa.gov/fire for graphic product...
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0212 PM CDT Tue Jun 30 2026
Valid 011200Z - 021200Z
...CRITICAL FIRE WEATHER AREA FOR NORTHEAST ARIZONA...SOUTHEAST
UTAH...WESTERN COLORADO...AND NORTHWEST NEW MEXICO...
The Critical fire weather risk area was slightly expanded based on
recent guidance. Otherwise, the forecast remains on track. See the
previous discussion for more information.
..Elizalde-Garcia.. 06/30/2026
.PREV DISCUSSION... /ISSUED 1259 AM CDT Tue Jun 30 2026/
...Synopsis...
Broad upper-level troughing will continue over the West with
multiple shortwave troughs rotating through the flow. While flow
weakens aloft, deep well-mixed boundary layers will develop as
stronger winds aloft will mix to the surface again bringing another
day of dry and windy conditions to the greater Four Corners region.
...Greater Four Corners Region...
Critical fire weather conditions are expected again across northeast
Arizona, southeast Utah, western Colorado, and northwest New Mexico.
South-southwest sustained winds of 15-20 mph amid minimum RH of
3-10% will develop by the afternoon and continue into the evening.
Some forecast guidance suggests that the Critical area may have more
locally critical conditions. However, swaths of HREF 50%+
probabilities of critical winds/RH along with nearly a week of
dry/windy conditions for this region, and the active large wildfires
across the region justify a Critical area. Additionally, the drier
and windier forecast guidance has been more accurate and reliable
for this region recently. Locally elevated fire weather conditions
are expected from the eastern slopes of the southern Sierra across
the southern Great Basin. South-southwest winds of 10-20 mph amid
minimum RH of 8-20% are likely across this area.
...Please see www.spc.noaa.gov/fire for graphic product...
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