RSS Mesoscale Discussions from Storm Prediction Center
WW 437 SEVERE TSTM IA WI 021745Z - 030000Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 437
NWS Storm Prediction Center Norman OK
1245 PM CDT Thu Jul 2 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Northeast Iowa
Southwest Wisconsin
* Effective this Thursday afternoon and evening from 1245 PM
until 700 PM CDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph likely
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
A tornado or two possible
SUMMARY...Thunderstorms are intensifying over north-central Iowa.
These storms will track eastward along and north of a surface
boundary into a strongly unstable air mass. Damaging winds and
large hail are possible.
The severe thunderstorm watch area is approximately along and 45
statute miles north and south of a line from 25 miles south of Mason
City IA to 20 miles northeast of Dubuque IA. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU7).
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
26025.
...Hart
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WW 0437 Status Updates
STATUS FOR WATCH 0437 HAS NOT BEEN ISSUED YET
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MD 1438 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR MIDDLE TENNESSEE INTO NORTHERN ALABAMA
Mesoscale Discussion 1438
NWS Storm Prediction Center Norman OK
1216 PM CDT Thu Jul 02 2026
Areas affected...Middle Tennessee into northern Alabama
Concerning...Severe potential...Watch possible
Valid 021716Z - 021945Z
Probability of Watch Issuance...40 percent
SUMMARY...A severe thunderstorm watch is being considered for Middle
Tennessee into portions of northern Alabama this afternoon in
anticipation of thunderstorms capable of damaging wind gusts.
DISCUSSION...Based on the 12Z OHX sounding and current surface
observations, surface heating is beginning to reach and exceed
convective temperatures across much of the Southeast. Visible
satellite trends show a cumulus field increasing in both extent and
depth, and HRRR-based mesoanalysis shows MLCINH effectively gone
across much of Middle Tennessee into northern Alabama. While
convective activity has yet to develop, the expectation is that
convective initiation should occur by mid-afternoon. Given steep
mid-level lapse rates from the 12Z OHX sounding (a new daily max
record of 7.5 C/km), modest precipitable water content of 1.72 in,
and generally weak flow aloft, thunderstorms will be capable of
intense downdrafts with strong to severe wind gusts. While the upper
flow generally doesn't support convective organization, storms may
organize along outflow boundaries that will pose locally higher
risks for damaging winds. Conditions will continue to be monitored
for a severe thunderstorm watch this afternoon.
..Halbert/Hart.. 07/02/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LMK...OHX...BMX...HUN...PAH...MEG...
LAT...LON 36818797 36868734 36818676 36748646 36658627 36378608
36068594 35778586 35488585 35028589 34538600 34178616
34108622 33988651 34018757 34128824 34228851 34578904
35248932 35588934 36078908 36648844 36818797
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1124 AM CDT Thu Jul 02 2026
Valid 021630Z - 031200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING ACROSS PARTS OF EASTERN SOUTH DAKOTA...SOUTHWEST
MINNESOTA...AND NORTHWEST IOWA....
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE DAKOTAS
INTO THE WESTERN GREAT LAKES...OVER THE SOUTHERN APPALACHIANS AND
TENNESSEE VALLEY...AND OVER WESTERN KANSAS...
...SUMMARY...
Scattered severe storms will be possible from the northern Plains
into the Midwest and Great Lakes regions today into tonight, as well
as across the southern Appalachians and Tennessee Valley this
afternoon and early evening.
...SD to WI...
Morning water vapor imagery shows several weak and/or convectively
induced shortwave troughs moving across the northern Plains into the
Upper Midwest. This area will have widespread marginal to moderate
afternoon CAPE and dewpoints in the 60s to lower 70s. This leads to
a forecast of a large area of potential thunderstorm development,
but with weak/nebulous forcing and general height-rises aloft. As
such, the overall confidence in this forecast is not very high.
Storms are likely to focus along a boundary currently evident from
southern SD into central IA. Convection currently developing in
northern IA near the boundary should continue to intensify through
the afternoon and track into southern WI/northern IL with a severe
wind/hail threat.
Other intense thunderstorm clusters are expected to develop along
the SD/NE portion of the boundary by mid/late afternoon, also with a
risk of large hail and damaging wind gusts.
...Western KS...
Full sunshine and dewpoints in the 60s will lead to a region of
strong instability over western KS this afternoon. Most CAM
solutions suggest at least isolated thunderstorms form along the
KS/CO border and spread slowly eastward during the evening. A
deeply mixed boundary layer and sufficient CAPE suggest a risk of
damaging wind gusts in the strongest cells.
...TN Valley/Southern Appalachians...
A widespread very moist and unstable air mass is present today
across this region, with full sunshine leading to steep low-level
lapse rates and MLCAPE values over 4000 J/kg. Weak forcing under an
upper ridge limits confidence in timing/location of storms.
However, widely scattered thunderstorm development should eventually
result in merging outflows and the risk of gusty/damaging winds this
afternoon and early evening across the region.
..Hart/Halbert.. 07/02/2026
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1217 PM CDT Thu Jul 02 2026
Valid 031200Z - 041200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM CENTRAL
NEBRASKA INTO WESTERN IOWA...
...SUMMARY...
Scattered wind damage and large hail are expected from parts of
Nebraska into Iowa Friday. Isolated to scattered severe storms are
also possible extending eastward from the northern/central Plains
into the Midwest, Tennessee Valley, and Mid-Atlantic.
...Synopsis...
An upper high will remain over the Appalachians and Carolinas, with
a somewhat weaker ridge aloft extending westward into the southern
Rockies. Relatively cool midlevel temperatures will generally
stretch from the northern Plains and across much of the Great Lakes
an Northeast, as modest mid and high level westerlies persist. In
the low levels, substantial moisture and instability will persist
across those same areas, as south to southwest surface winds
maintain 70s F dewpoints around the northern periphery of a
southeast U.S. surface high. An east-west oriented boundary will
stretch from the northern Plains eastward across the Great Lakes
region, with various clusters of thunderstorms throughout the period
within this unstable zone.
...Northern/Central Plains...
Any outflows from overnight convection are likely to mix, with
strong instability developing. Cells will form over the northern
High Plains initially with localized hail and wind. Larger coverage
of storms will occur from southern SD into northern NE during the
mid/late afternoon, with general upscale growth into one or more
MCSs. However, supercells may occur initially with large hail and a
brief tornado. Supporting a severe MCS will be ample precipitable
water, strong instability, and an increasing southerly low-level jet
during the evening. Additional isolated hail or wind may occur near
the surface trough into western KS and toward the TX Panhandle where
temperatures will be hot.
...Much of the Midwest to the Lower Great Lakes and across NY, PA
and NJ...
The entire corridor stretching from northern IL/southern WI into NY
and NJ will destabilize with daytime heating and robust moisture.
Storms are most likely from WI/IL during the late afternoon, and
also near the Lower Great Lakes, affecting OH, PA, NY. Modest
westerlies aloft and the uncapped air mass across the area will
support a few longer-lived clusters of storms capable of damaging
wind gusts. Some of the activity may proceed into western New
England into early evening.
...TN Valley and northern GA...
Within the weak easterly flow regime aloft, just south of the upper
ridge, storms are expected to form during the afternoon with the
very moist and unstable air mass. Mid 70s F dewpoints will again
lead to strong instability, with multicell clusters moving
west/northwest by mid/early afternoon. Locally damaging wind gusts
are possible.
..Jewell.. 07/02/2026
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1138 AM CDT Thu Jul 02 2026
Valid 021700Z - 031200Z
...CRITICAL FIRE WEATHER AREA FOR WESTERN/SOUTHERN
COLORADO...EASTERN UTAH...AND NORTHERN NEW MEXICO...
...Morning Update...
The forecast remains on track. Across the Greater Four Corners
region, poor overnight humidity recoveries and residual gusty winds
further intensified the fire environment, maintaining active
behavior on several wildfires through the early morning hours (as
depicted by satellite imagery). Daytime high temperatures will be a
few degrees warmer than yesterday, with critically low RH of 3-12%
across the Elevated and Critical risk areas. Stronger southwest
winds up to 20 mph (gusts up to 30 mph) are expected over much of
the Southern Rockies (and adjacent Plains) into the West Slope.
Across the Eastern Seaboard, ERCs are approaching the 90-95th
percentile. The Piedmont and Mid-Atlantic will see RH values decline
to 20-25% this afternoon, allowing locally elevated fire concerns to
emerge where dry fuels exist. Winds will be the limiting factor,
with terrain-induced gusts up to 10 mph possible.
See the previous discussion for more information.
..Elizalde-Garcia.. 07/02/2026
.PREV DISCUSSION... /ISSUED 1226 AM CDT Thu Jul 02 2026/
...Synopsis...
Upper-level troughing remains over the West with weak shortwave
troughs continuing to rotate through the flow. However, heights will
rise amid a warming trend across the West. A very dry airmass
remains in place across the greater Four Corners region.
...Greater Four Corners Region and southern Great Basin...
Southwest sustained winds of 12-20 mph gusting 20-30 mph amid
minimum RH of 3-12% are expected across the greater Four Corners
region. Continued poor RH recovery overnight will lead to extended
burn periods again, with most areas having 5-15 hours of at least
elevated fire weather conditions within the Elevated area. Portions
of the Critical area may have elevated conditions for nearly 20
hours, including in the vicinity of the Aspen Acres Fire. Large
swaths of the Colorado Rockies are near or setting new record high
ERC values, with ERCs exceeding the 90th percentile across the vast
majority of the Elevated area.
...Northern Great Basin...
Isolated dry thunderstorms are possible in portions of northeast
Nevada into southeast Idaho. However, given the low forecast MUCAPE
(<250 J/kg), rising heights, and limited mid-level moisture,
confidence is low that sufficient coverage of thunderstorms will
develop over the portions of eastern Nevada with more receptive
fuels (ERCs > 80th percentile).
...Please see www.spc.noaa.gov/fire for graphic product...
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