WW 219 SEVERE TSTM IA MN WI 180410Z - 180900Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 219
NWS Storm Prediction Center Norman OK
1110 PM CDT Sun May 17 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Eastern Iowa
Far Southeastern Minnesota
Southwest Wisconsin
* Effective this Sunday night and Monday morning from 1110 PM
until 400 AM CDT.
* Primary threats include...
Scattered damaging wind gusts to 65 mph possible
A tornado or two possible
SUMMARY...A squall line will move into the Watch area from the west
tonight. Damaging gusts will be the primary severe hazard with the
stronger surges of thunderstorm outflow but a brief tornado is also
possible.
The severe thunderstorm watch area is approximately along and 40
statute miles east and west of a line from 30 miles east of La
Crosse WI to 40 miles south southeast of Ottumwa IA. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU9).
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 216...WW 218...
AVIATION...A few severe thunderstorms with hail surface and aloft to
inches. Extreme turbulence and surface wind gusts to 55 knots. A
few cumulonimbi with maximum tops to 400. Mean storm motion vector
25040.
...Smith
WW 0219 Status Updates
STATUS REPORT ON WW 219
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 WNW CID
TO 40 E ALO TO 45 S LSE TO 25 SSE LSE TO 5 WSW LSE.
..MARSH..05/18/26
ATTN...WFO...ARX...DMX...DVN...
STATUS REPORT FOR WS 219
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC007-011-031-043-051-055-061-087-095-101-103-105-107-113-177-
179-183-180640-
IA
. IOWA COUNTIES INCLUDED ARE
APPANOOSE BENTON CEDAR
CLAYTON DAVIS DELAWARE
DUBUQUE HENRY IOWA
JEFFERSON JOHNSON JONES
KEOKUK LINN VAN BUREN
WAPELLO WASHINGTON
WIC023-043-103-123-180640-
WI
. WISCONSIN COUNTIES INCLUDED ARE
CRAWFORD GRANT RICHLAND
VERNON
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
WW 0218 Status Updates
STATUS REPORT ON WW 218
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 ENE STJ
TO 15 SSW LWD TO 10 N LWD TO 15 SW OXV TO 15 NNE OXV TO 45 W CID.
..MARSH..05/18/26
ATTN...WFO...DMX...EAX...
STATUS REPORT FOR WT 218
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC053-117-123-125-135-157-185-180640-
IA
. IOWA COUNTIES INCLUDED ARE
DECATUR LUCAS MAHASKA
MARION MONROE POWESHIEK
WAYNE
MOC081-129-180640-
MO
. MISSOURI COUNTIES INCLUDED ARE
HARRISON MERCER
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.
WW 0217 Status Updates
STATUS REPORT ON WW 217
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..JEWELL..05/18/26
ATTN...WFO...DDC...
STATUS REPORT FOR WT 217
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
KSC047-057-083-097-135-145-151-165-185-180340-
KS
. KANSAS COUNTIES INCLUDED ARE
EDWARDS FORD HODGEMAN
KIOWA NESS PAWNEE
PRATT RUSH STAFFORD
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.
WW 0216 Status Updates
STATUS REPORT ON WW 216
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 ESE SLB
TO 20 NW FOD TO 35 S FRM TO 20 S FRM TO 15 NNE SPW TO 30 W FRM TO
20 NNE FRM TO 10 SSE MKT TO 20 NE MKT.
..JEWELL..05/18/26
ATTN...WFO...DMX...ARX...MPX...
STATUS REPORT FOR WT 216
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC017-023-033-037-063-065-067-069-081-089-091-109-131-151-189-
191-195-197-180340-
IA
. IOWA COUNTIES INCLUDED ARE
BREMER BUTLER CERRO GORDO
CHICKASAW EMMET FAYETTE
FLOYD FRANKLIN HANCOCK
HOWARD HUMBOLDT KOSSUTH
MITCHELL POCAHONTAS WINNEBAGO
WINNESHIEK WORTH WRIGHT
MNC013-039-043-045-047-091-099-109-147-161-180340-
MN
. MINNESOTA COUNTIES INCLUDED ARE
BLUE EARTH DODGE FARIBAULT
FILLMORE FREEBORN MARTIN
MOWER OLMSTED STEELE
WASECA
WW 0214 Status Updates
STATUS REPORT ON WW 214
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 SW CNK TO
15 ESE CNK TO 40 ENE CNK TO 15 ENE BIE TO 30 W SDA TO 10 SE OMA
TO 25 E OMA TO 5 NNE DNS.
..JEWELL..05/18/26
ATTN...WFO...OAX...TOP...GID...ICT...
STATUS REPORT FOR WT 214
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC071-085-129-137-145-155-165-180340-
IA
. IOWA COUNTIES INCLUDED ARE
FREMONT HARRISON MILLS
MONTGOMERY PAGE POTTAWATTAMIE
SHELBY
KSC009-013-027-029-041-053-061-105-117-131-143-149-159-161-167-
169-201-180340-
KS
. KANSAS COUNTIES INCLUDED ARE
BARTON BROWN CLAY
CLOUD DICKINSON ELLSWORTH
GEARY LINCOLN MARSHALL
NEMAHA OTTAWA POTTAWATOMIE
RICE RILEY RUSSELL
SALINE WASHINGTON
No Mesoscale Discussions are in effect as of Mon May 18 06:13:02 UTC 2026.Public Severe Weather Outlook
PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0106 AM CDT MON MAY 18 2026
...Severe thunderstorms expected over parts of the south-central
Plains and mid Missouri Valley this afternoon and evening...
* LOCATIONS...
Iowa
Central and Eastern Kansas
Northwest Missouri
Southeast Nebraska
Northern Oklahoma
* HAZARDS...
Several tornadoes, a couple intense
Scattered damaging winds, some hurricane force
Widespread baseball-size hail
* SUMMARY...
Numerous severe thunderstorms are expected this afternoon and
evening across the south-central Plains and mid Missouri Valley.
Supercells capable of very large hail and strong to intense
tornadoes are most likely from central Kansas and southeast
Nebraska into Iowa and northwest Missouri.
Preparedness actions...
Review your severe weather safety procedures for the possibility
of dangerous weather today. Stay tuned to NOAA Weather Radio,
weather.gov, or other media for watches and warnings. A tornado
watch means that conditions are favorable for tornadoes to form
during the next several hours. If a tornado warning is issued for
your area, move to a place of safety, ideally in a basement or
interior room on the lowest floor of a sturdy building.
&&
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Mon May 18 2026
Valid 181200Z - 191200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS
EASTERN/SOUTH-CENTRAL KANSAS AND SOUTHEAST NEBRASKA/FAR NORTHWEST
MISSOURI...
...SUMMARY...
Numerous severe thunderstorms are expected this afternoon and
evening across the south-central Plains and Middle Missouri Valley.
Supercells capable of very large hail and strong to intense
tornadoes are most likely from central Kansas and southeast Nebraska
into Iowa and northwest Missouri.
...Central Plains and Midwest...
A regional outbreak of severe storms, potentially including
strong/intense tornadoes (EF2/EF3+), is expected across the central
Plains during the late afternoon and evening, although some
uncertainties persist regarding the upper-end magnitude/spatial
details of the heightened tornado potential. An extensive MCS exists
early in the overnight from eastern/central Iowa southwestward into
northeast/central Kansas, where regenerative/repetitive storms
persist.
This MCS should weaken/lose integrity through the early morning,
although convection may regenerate and intensify again along
composite outflow, eastward across the middle Mississippi Valley and
lower Ohio Valley and potentially parts of the Great Lakes within a
destabilizing air mass this afternoon. Damaging winds should be the
most probable risk, although some tornado and hail potential will
exist as well.
The western fringe of this remnant cold pool will modify early today
with a steady northward flux of low-level moisture, with a very
unstable environment unfolding by mid/late afternoon across
south-central/eastern Kansas into far west/northwest Missouri and
Iowa/far southeast Nebraska. As a shortwave trough/speed max emerges
from the central Rockies, deep convective development is expected
along the initially stalled or slow-moving
northeast/southwest-oriented front across central/northeast Kansas
and southeast Nebraska and western Iowa by late afternoon.
This increasingly rich low-level moisture will reside beneath an
elevated mixed layer characterized by 8-9 C/km mid-level lapse
rates, resulting in MLCAPE 3000-4000 J/kg. Mass response to the
ejecting wave, along with a northeastward-translating 60-70 kt
mid-level jet, and a significantly strengthening low-level jet by
sunset, will yield increasingly favorable wind profiles for intense
supercells capable of very large hail and tornadoes. This may
includes strong and potentially intense tornadoes (EF2/EF3+). That
said, the duration of a semi-discrete storm mode remains a key
question, given the parallel orientation of the stalled front and
the deep-layer shear vectors, and that the front will trend more
southeastward-progressive during the evening. Thus, the
strong/potentially intense tornado threat will peak prior to upscale
growth into line segments along the front, with severe outflow gusts
and embedded circulations becoming the main concerns over time
tonight as storms progress east-southeastward across the Lower
Missouri Valley and middle Mississippi Valley.
...Oklahoma and western North Texas...
Storm development along the dryline across western Oklahoma into
western North Texas/Lower Rolling Plains is more uncertain given
more limited forcing for ascent. If/where storms do form, there is
the potential for very large hail and a conditional risk for
tornadoes. A consistently forecast flow weakness above 400 mb
by late afternoon/evening does not appear favorable for particularly
long-lived storms if they do form.
...Mid-Atlantic/Northeast States...
Influenced by terrain and a surface trough, isolated strong to
locally severe storms capable of wind damage could occur this
afternoon within a moderately unstable environment.
..Guyer/Squitieri.. 05/18/2026
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1254 AM CDT Mon May 18 2026
Valid 191200Z - 201200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE GREAT
LAKES TO THE SOUTHERN PLAINS...
...SUMMARY...
Widely scattered severe thunderstorms will be possible along a cold
front extending from the Great Lakes into the Ohio Valley and the
southern Plains on Tuesday. Damaging winds and large hail will be
the primary threats.
...Synopsis...
A mid-level trough will lift across the Great Lakes Region on
D2/Tuesday with a surface low moving east across southern Ontario
and Quebec. A trailing cold front will be located from the Great
Lakes south into the Ohio and mid Mississippi Valleys into the
Southern Plains. Convection will likely be ongoing across this
boundary at the beginning of the D2/Tuesday period.
...Great Lakes Vicinity to the Lower Ohio Valley...
Some convection may be ongoing across the cold front towards the
beginning of the D2 period, with additional development likely by
the afternoon along the eastward shifting cold front. Enhanced
mid-level flow aloft and weak to moderate instability will support
organized storms with potential for damaging winds and isolated
large hail. Additional afternoon thunderstorm development may extend
into the Northeast with potential for large hail and damaging wind.
...Mid Mississippi Valley to Southern Plains...
Convection will be ongoing at the start of the period from the mid
Mississippi Valley driven by the cold front and potential cold pool
propagation. These boundaries will be the focus of
re-intensification of convection in the afternoon. Mid-level flow
aloft will be weaker across the region but sufficient shear for
organization should remain in place. A plume of more favorable
moderate to strong instability will be available across
central/northern Texas into southern Oklahoma. With afternoon
development, steep low to mid level lapse rates and moderate
instability will support potential for a few large hail reports.
With time, upscale growth will support a downstream damaging wind
risk.
..Thornton.. 05/18/2026
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