RSS Mesoscale Discussions from Storm Prediction Center
WW 301 SEVERE TSTM IA IL MN WI 101700Z - 110000Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 301
NWS Storm Prediction Center Norman OK
1200 PM CDT Wed Jun 10 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Far Eastern Iowa
Northwest Illinois
Extreme Southeast Minnesota
Wisconsin
* Effective this Wednesday afternoon and evening from NOON until
700 PM CDT.
* Primary threats include...
Scattered large hail likely with isolated very large hail events
to 2 inches in diameter possible
Scattered damaging wind gusts to 70 mph likely
A tornado or two possible
SUMMARY...Ongoing convective line across far east-central Iowa is
forecast to continue northeastward into central/southern Wisconsin,
with an attendant threat for damaging gusts. Additional development
is anticipated farther north from far southeast Minnesota into
northern Wisconsin. Some initially cellular development could
produce large hail. Quick transition to a more linear mode is
expected here as well, with damaging wind then becoming the primary
risk.
The severe thunderstorm watch area is approximately along and 105
statute miles north and south of a line from 55 miles north
northwest of Cedar Rapids IA to 60 miles east southeast of Mosinee
WI. For a complete depiction of the watch see the associated watch
outline update (WOUS64 KWNS WOU1).
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
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
24040.
...Mosier
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WW 0301 Status Updates
STATUS FOR WATCH 0301 HAS NOT BEEN ISSUED YET
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MD 1064 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR EASTERN IOWA...NORTHEASTERN MISSOURI...SOUTHWESTERN WISCONSIN...AND NORTHWESTERN ILLINOIS
Mesoscale Discussion 1064
NWS Storm Prediction Center Norman OK
1109 AM CDT Wed Jun 10 2026
Areas affected...Eastern Iowa...northeastern Missouri...southwestern
Wisconsin...and northwestern Illinois
Concerning...Severe potential...Watch likely
Valid 101609Z - 101815Z
Probability of Watch Issuance...80 percent
SUMMARY...Scattered thunderstorms are currently moving northeastward
through central Iowa and northeastern Missouri. These storms may
gradually strengthen in the next couple of hours, posing a threat
for wind gusts and small hail. A watch will likely be needed soon in
the northern portion of the highlighted area.
DISCUSSION...A couple of thunderstorm complexes are moving through
central IA and northeastern MO this morning. A few 40+ kt gusts have
been reported across central IA with the strongest cores. Per
current mesoanalysis, they are located along the leading edge of a
mid-level impulse propagating through IA in a zone of broad
upper-level difluence. Modest heating amidst scattered cloud cover
is yielding gradual warming into the low-/mid-80s F which --
combined with dewpoints in the lower 70s F -- supports MLCAPE around
1500 J/kg ahead of the storms. Bulk shear is around 25-30 kts,
increasing to around 30-35 kts in the northern portion of the
highlighted area.
The general expectation is for these storms to gradually intensify
as they move northeastward during the next couple of hours.
Convective evolution remains uncertain; some high-resolution
guidance depicts a consolidated cold pool and bowing system, while
others depict more discrete through early afternoon. Regardless of
mode, the background environment should support a gradually
ramping-up threat for wind gusts and small hail. Watch issuance is
likely in the short term in the delineated area to cover these
threats.
..Flournoy/Mosier.. 06/10/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LOT...ILX...MKX...LSX...DVN...ARX...DMX...EAX...
LAT...LON 40308978 39319127 39109248 39299281 40089239 40709192
41359206 41939258 42239359 42869326 43229286 43469204
42989031 41838962 40308978
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
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SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1132 AM CDT Wed Jun 10 2026
Valid 101300Z - 111200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER/MID MISSISSIPPI VALLEYS AND MIDWEST...
...SUMMARY...
Scattered to numerous severe thunderstorms with potential for large
hail in excess of two inches in diameter, a few strong tornadoes and
damaging winds with gusts over 75 mph are expected this afternoon
and evening across parts of the Upper Mississippi Valley and
Midwest.
...Mid/Upper MS Valley into the central Plains...
Regional radar imagery shows an ongoing cluster of strong
thunderstorms across southern IA and northern MO, supported by a
residual low-level jet that currently extends from KS/northern OK
into the region. Heating of the very moist airmass downstream will
result in limited convective inhibition and strong to very strong
buoyancy by the early afternoon. Reintensification of the ongoing
cluster is anticipated as it moves within this destabilizing
airmass. Deep-layer shear will be modest but still sufficient for
some organization, and the development of a strong to occasionally
severe bowing line segment appears probable, particularly from
northeast IA into southern WI and northern IL. New updrafts ahead of
the line could also produce hail early in the convective cycle,
while also potentially contributing to updraft augmentation as they
merge into the line. Some isolated hail could result from this
augmentation as well.
Farther north, recent surface analysis placed a triple point low
over northeast SD. An occluded front extends north-northwestward
from this low across eastern ND into central Manitoba, while cold
front extends southward to another low over northeast NE and then
back southwestward across the central Plains. The frontal zone and
triple point low are forecast to progress eastward into the Upper
Midwest, interacting with a diurnally destabilizing airmass to
support thunderstorm development. Ample low-level moisture (i.e.
dewpoints in the upper 60s/low 70s) will support strong buoyancy,
despite modest lapse rates, and moderate deep-layer vertical shear
should be sufficient for updraft organization. As a result, strong
to severe thunderstorms are expected along and just ahead the front,
with large hail as the primary threat. Isolated very large hail to
2" in diameter could occur. Some damaging gusts are possible as
storms transition into bowing line segments over time. There is also
a low-probability for a few brief tornadoes, particularly with any
more cellular development from central into eastern WI from 21 to
00Z.
An additional severe threat will likely materialize this evening in
the wake of the afternoon MCS within the recovered airmass from the
Mid MS Valley westward through the Mid MO Valley into the central
Plains. The impetus for this redevelopment will likely be a complex
combination of low-level convergence along the approaching front,
low-level convergence and warm-air advection along remnant outflow,
and modest large-scale ascent. Development along the front appears
most likely from central IA southwestward into northeast KS, while
development along the outflow appears most likely northwest IL
across southern IA. The airmass in all of these areas will likely
feature ample low-level moisture (i.e. dewpoints in the low to mid
70s), warm surface temperatures (highs in the low 90s), and at least
modestly steep mid-level lapse rates. This will result in strong to
extreme buoyancy, with MLCAPE values exceeding 3000 J/kg from
northeast KS into southern IA, northern MO, and west-central IL.
Complex surface pattern will likely yield limited predictability for
the primary severe hazard this evening. Given the extreme buoyancy
and moderate mid-level flow, any more cellular development that is
able to mature should become supercellular, with all severe hazards
possible, including very large hail and tornadoes. Storm interaction
and strong downdrafts will likely make maintaining a discrete mode
difficult, but low-level hodographs support the potential for a
strong tornado, particularly from 00 to 03Z amid a strengthening
low-level jet.
Lastly, early morning strong to severe thunderstorms are possible
across central/eastern NE as a secondary branch of the low-level jet
develops in response to another shortwave trough moving into the
central High Plains.
...Ohio Valley/Central Appalachians/Mid-Atlantic States...
A moist and unstable airmass will be in place today across much of
the region, with surface dewpoints generally in the lower 70s F.
While some thunderstorms are ongoing early today, additional and
more potent thunderstorm development is expected into the afternoon
as the boundary layer destabilizes. These storms will be further
influenced by a pair of weak eastward-moving MCVs, one over the
upper Ohio River Valley and the other over the central Appalachians.
Damaging winds, associated with water-loaded downbursts, will be the
primary hazard regionally.
..Mosier/Flournoy.. 06/10/2026
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1037 AM CDT Wed Jun 10 2026
Valid 101700Z - 111200Z
...CRITICAL FIRE WEATHER AREA FOR EAST-CENTRAL WYOMING AND FAR
NORTHWEST NEBRASKA...
No changes were made to the drawn area. Satellite imagery shows
mostly sunny skies across much of both Elevated areas this morning.
Only a few mid-level clouds exist over eastern portions of CO and WY
which are not expected to affect the forecast today. Surface
observations over the high terrain of central CO and the plains of
WY already show strong westerly winds sustained above 15-20 mph in
favored areas. RHs are also hovering around 20-35% over much of the
same region. Thus, surface conditions remain in agreement with the
latest forecast guidance and no changes are necessary.
Significant fire growth occurred yesterday and last night on the
South Fork Fire, which is again included in the eastern extent of
the highlighted Critical area today. Relief in the form of well
below normal temperatures will be on the way over the next few days.
..Stearns.. 06/10/2026
.PREV DISCUSSION... /ISSUED 1234 AM CDT Wed Jun 10 2026/
...Synopsis...
An elongated upper trough will extend from the Pacific Northwest to
the Upper Midwest with an attendant 60-80 kt jet across the Rockies,
aiding in surface low development over eastern CO/western KS.
Amplified westerly flow aloft and surface troughing will enhance
windy conditions amid a dry airmass across the Great Basin into the
central Plains, continuing widespread fire concerns as fuels
approach critical thresholds. At the base of the exiting upper
trough, deep northerly flow will promote dry and breezy conditions
into the Sacramento Valley where dry fine fuels exist.
...Eastern Great Basin, Colorado Plateau and central High Plains...
Strong westerly surface winds in the wake of a cold front beneath
pronounced mid-level flow will continue fire weather concerns across
portions of the central Plains today. West winds of 25-30 mph and RH
as low as 15% will align with pockets of dry fuels, maintaining a
Critical fire weather threat in eastern WY and far northwestern NE.
Weaker, but still impactful westerly flow will support Elevated fire
weather conditions in the eastern Great Basin and Four Corners
regions as westerly 10-15 mph winds and RH values of 10-15% overlap
dry fuels. Across portions of southeast UT, a fairly small corridor
may experience localized areas of briefly critical winds
(west-southwesterly at 15-25 mph) amidst widespread warm and dry
conditions.
...Sacramento Valley...
Dry, post-frontal northerly flow funneling into the Sacramento
Valley will promote an Elevated fire weather threat to the region
and adjacent valley foothills. Sustained northerly winds of 10-15
mph (locally up to 20 mph) and RH at or below 15% are expected to
coalesce amid receptive fuels to support fire spread. Dry and breezy
conditions will persist into the overnight hours, leading to an
extended burning period and continued fire weather concerns on Day
2/Thursday.
...Please see www.spc.noaa.gov/fire for graphic product...
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