SPC MD 755

MD 0755 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF THE CENTRAL GREAT PLAINS

Mesoscale Discussion 0755
NWS Storm Prediction Center Norman OK
0338 PM CDT Sun May 17 2026

Areas affected...portions of the central Great Plains

Concerning...Severe potential...Watch possible 

Valid 172038Z - 172245Z

Probability of Watch Issuance...40 percent

SUMMARY...Isolated thunderstorm development is possible across the
eastern Texas Panhandle, northwest Oklahoma, and south-central
Kansas along a dryline this evening, with a conditional threat for
all severe hazards. Trends are being monitored for possible watch
issuance.

DISCUSSION...Latest surface analysis depicts a surface low near the
Kansas/Nebraska border with a trailing dryline extending
south-southwestward through central Kansas into northwest Oklahoma
and the Texas Panhandle, with recent visible satellite imagery
depicting sporadic Cu developing along this boundary. East of the
dryline, steep mid-level lapse rates (8.5+ C/km) and rich low-level
moisture (as sampled by the 18z OUN/DDC observed soundings) are
supporting strong instability, with 2500-3500+ J/kg MLCAPE analyzed
via latest mesoanalysis. 

Notable uncertainty remains regarding the development of sustained
thunderstorms owing to strong capping sampled by the 18z OUN
sounding and nebulous upper-level forcing. While effective shear is
forecast to remain modest (generally 25-35 kts), a conditional
severe threat exists should a storm develop. The aforementioned
steep mid-level lapse rates and modest effective shear would support
a threat for large hail, with a strengthening southerly low-level
jet also promoting an increasing tornado threat this evening with
any developing/persistent supercells. Some high-res guidance also
suggests some potential for the development of a linear segment,
which would favor a greater risk for severe/damaging wind gusts.

Trends will continue to be monitored, and watch issuance could be
needed should convective initiation appear likely/imminent given
this conditional severe threat.

..Chalmers/Mosier.. 05/17/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...ICT...OUN...DDC...AMA...

LAT...LON   35550050 36979991 38119945 38459914 38499853 38209813
            37459785 36749802 36229829 35609888 34909979 34790007
            34770041 34910059 35230062 35550050 

MOST PROBABLE PEAK TORNADO INTENSITY...100-125 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN

SPC MD 754

MD 0754 CONCERNING TORNADO WATCH 213... FOR PORTIONS OF SOUTHEAST SD...FAR NORTHWEST IA...AND FAR SOUTHWEST MN

Mesoscale Discussion 0754
NWS Storm Prediction Center Norman OK
0331 PM CDT Sun May 17 2026

Areas affected...portions of southeast SD...far northwest IA...and
far southwest MN

Concerning...Tornado Watch 213...

Valid 172031Z - 172200Z

The severe weather threat for Tornado Watch 213 continues.

SUMMARY...A swath of damaging winds up to 80 mph is possible
downstream of an ongoing bow moving east/northeast across southeast
SD this afternoon.

DISCUSSION...A small but well-organized bow is ongoing across
southeast South Dakota this afternoon. This storm has produced gusts
near 80 mph over the past hour. The downstream environment remains
favorable for a continuation of damaging wind swaths as convection
moves along the gradient of moderate instability oriented across the
region. Regional VWP data shows midlevel flow increasing to around
40-50 kt with rich low-level moisture in place across far southeast
SD and northwest IA. Radar presentation recently suggests a
rear-inflow jet may be developing, which aligns with strengthening
midlevel flow noted in regional VWP. This supports a continued risk
for strong to intense damaging winds to near 80 mph over the next
1-2 hours as the system continues east/northeast near 45-50 kt.

..Leitman.. 05/17/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FSD...OAX...

LAT...LON   43769797 44039626 43799540 43409534 43089557 42799662
            42719741 42669810 42899822 43399827 43769797 

MOST PROBABLE PEAK TORNADO INTENSITY...120-145 MPH
MOST PROBABLE PEAK WIND GUST...75-90 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN

SPC MD 753

MD 0753 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR NORTHEAST COLORADO VICINITY

Mesoscale Discussion 0753
NWS Storm Prediction Center Norman OK
0308 PM CDT Sun May 17 2026

Areas affected...northeast Colorado vicinity

Concerning...Severe potential...Watch possible 

Valid 172008Z - 172245Z

Probability of Watch Issuance...60 percent

SUMMARY...Isolated high-based thunderstorms may pose a risk for
strong wind gusts and large hail through this evening. A severe
thunderstorm watch may be needed sometime late this afternoon, but
timing is uncertain.

DISCUSSION...Isolated thunderstorms have developed near the
foothills in the I-25 corridor in central CO. This activity may
continue to develop and shift east/northeast over the next few
hours. The downstream airmass is relatively cool and dry in the wake
of a prior cold frontal passage. However, steep midlevel lapse rates
and strong vertical shear are present. RAP forecast soundings
indicate elongated/straight hodographs amid steep low and midlevel
lapse rates. This may be sufficient for isolated severe storms
capable of strong downburst winds and large hail. Trends will be
monitored for possible severe thunderstorm watch issuance later this
afternoon.

..Leitman/Mosier.. 05/17/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LBF...GLD...PUB...BOU...

LAT...LON   40680337 40950235 40870187 40330150 39370127 39240135
            38920172 38730249 38570418 38660456 38890488 39260504
            39610511 39880506 40140468 40330434 40680337 

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN

SPC MD 751

MD 0751 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF CENTRAL LOWER MICHIGAN

Mesoscale Discussion 0751
NWS Storm Prediction Center Norman OK
0232 PM CDT Sun May 17 2026

Areas affected...portions of central Lower Michigan

Concerning...Severe potential...Watch possible 

Valid 171932Z - 172200Z

Probability of Watch Issuance...40 percent

SUMMARY...Thunderstorms may pose a risk for large hail and damaging
wind gusts, with some potential for a tornado or two. Watch issuance
is possible.

DISCUSSION...Latest GOES water vapor imagery reveals an MCV over
south-central Wisconsin, in close proximity to persistent elevated
convection that has been ongoing through the morning and into the
afternoon hours. Downstream of these features, latest surface
analysis indicates a quasi-stationary surface boundary/warm front
extending roughly west-east across central Lower Michigan with
recent convective development noted north of Grand Rapids. South of
this boundary, temperatures in the mid-80s and dewpoints in the low
60s F are contributing 500 to locally 1500 J/kg MLCAPE. 35-45 kts of
effective bulk shear (per latest mesoanalysis) is sufficient to
support multicells/supercells with any convection that develops
along/south of this boundary. This will promote the potential for
large hail and damaging wind gusts with any sustained convection
this afternoon.

With time, a strengthening southerly low-level jet is forecast to
yield an increase in low-level hodograph curvature into this
evening, which would favor at least some increase in the threat for
a tornado or two, particularly with any supercell/convection that
can favorably interact with the warm front. Uncertainty remains
regarding convective coverage and persistence within the warm
sector, however. Trends will continue to be monitored, and watch
issuance may eventually be needed.

..Chalmers/Mosier.. 05/17/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...DTX...APX...GRR...

LAT...LON   42718592 42888628 43378655 43828661 44218648 44508618
            44588460 44578373 44478329 44208285 43898253 43528246
            43198259 42958316 42808366 42728508 42718592 

MOST PROBABLE PEAK TORNADO INTENSITY...100-125 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN