URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 581
NWS Storm Prediction Center Norman OK
545 AM CDT Thu Aug 13 2026

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Central and Eastern Iowa

* Effective this Thursday morning from 545 AM until 1100 AM CDT.

* Primary threats include...
  Scattered damaging winds likely with isolated significant gusts
    to 75 mph possible
  Isolated large hail events to 1 inch in diameter possible
  A tornado or two possible

SUMMARY...A bow echo will continue east across central into eastern
Iowa this morning.  Scattered severe gusts primarily in the 60 to 75
mph range will be the primary hazard.  A brief tornado or localized
corridor of more substantial gusts will be possible with any
stronger mesovortex embedded within the squall line.

The severe thunderstorm watch area is approximately along and 50
statute miles north and south of a line from 30 miles west northwest
of Des Moines IA to 45 miles southeast of Cedar Rapids IA. 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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 580...

AVIATION...A few severe thunderstorms with hail surface and aloft to
1 inch. Extreme turbulence and surface wind gusts to 65 knots. A few
cumulonimbi with maximum tops to 550. Mean storm motion vector
27045.

...Smith

STATUS REPORT ON WW 581

SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 NNW LWD
TO 25 NE OXV TO 40 SSW ALO TO 30 WSW ALO.

FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1966

..CHALMERS..08/13/26

ATTN...WFO...DVN...DMX...


STATUS REPORT FOR WS 581 

SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS 

IAC011-031-039-057-075-087-095-101-103-105-107-111-113-115-117-
123-125-135-139-157-171-177-179-181-183-131440-

IA 
.    IOWA COUNTIES INCLUDED ARE

BENTON               CEDAR               CLARKE              
DES MOINES           GRUNDY              HENRY               
IOWA                 JEFFERSON           JOHNSON             
JONES                KEOKUK              LEE                 
LINN                 LOUISA              LUCAS               
MAHASKA              MARION              MONROE              
MUSCATINE            POWESHIEK           TAMA                
VAN BUREN            WAPELLO             WARREN              
WASHINGTON           


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.

STATUS REPORT ON WW 580

SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 WNW LWD
TO 35 NNW LWD.

REMAINING VALID PORTION OF WW MAY BE ALLOWED TO EXPIRE AS SCHEDULED
AT 13/13Z.

..KERR..08/13/26

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


STATUS REPORT FOR WS 580 

SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS 

IAC175-131300-

IA 
.    IOWA COUNTIES INCLUDED ARE

UNION                


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.

Mesoscale Discussion 1967
NWS Storm Prediction Center Norman OK
1028 AM CDT Thu Aug 13 2026

Areas affected...central Illinois

Concerning...Severe potential...Watch possible 

Valid 131528Z - 131800Z

Probability of Watch Issuance...60 percent

SUMMARY...Strong to severe storms will move out of Iowa and into
Illinois this morning. Depending on storm trends, a watch could be
needed for scattered damaging gusts.

DISCUSSION...A well-defined MCS continues to push across eastern IA,
with primary convective line over southeast IA and into far
northeast MO. Storm trends suggest some weakening has occurred over
the past few hours, though locally strong gusts have been reported
over IA.

Downstream of this system, cooler/more stable air exists over
northern IL and IN, with an instability gradient extending from
central IL into southern IN. This instability may develop very
slowly northward during the afternoon. Wind shear is a bit marginal
for sustained storms, but midlevel westerlies around 30 kt, combined
with strengthening low-level winds during the afternoon may provide
a slightly better environment.

..Jewell.. 08/13/2026

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

ATTN...WFO...LOT...ILX...LSX...DVN...

LAT...LON   41469160 41148780 40908759 40178763 39768794 39808884
            40129059 40309148 40479187 40669197 41139167 41469160 

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0738 AM CDT Thu Aug 13 2026

Valid 131300Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL IOWA
INTO EAST-CENTRAL ILLINOIS...

...SUMMARY...
Isolated to scattered severe thunderstorms are possible today from
parts of the southern/central High Plains to the mid Mississippi and
lower Ohio Valleys.  Severe gusts capable of wind damage should be
the main threat, but occasional hail may also occur.

...Iowa into Illinois/Indiana...
Radar mosaic/IR imagery loops show a long-lived MCS over central IA
moving east towards the MS River this morning.  Widely scattered
severe gusts 60-70 mph are possible with the more intense bowing
structures and short-lived mesovortices embedded within the line,
along with a brief tornado risk (for short-term details, reference
MCD #1966).  This activity will continue into IL but limited
confidence regarding its evolution and subsequent severe risk cast
uncertainty whether it will reinvigorate or additional strong/severe
storms will develop on the leading edge of outflow.  Regardless, a
moist airmass across the eastern Corn Belt will destabilize amid a
veil of high clouds.  Forecast model guidance shows 35-45 effective
shear supporting organized storms.  Isolated to scattered damaging
gusts will be the primary severe hazard, although a brief tornado
and marginally severe hail are also possible through the early
evening.

...Southern/Central High Plains...
High-based thunderstorms are forecast to initially develop over the
higher terrain of the central Rockies/Front Range this afternoon,
with post-frontal low-level upslope flow persisting across the
central High Plains.  Storm motions into slightly richer moisture
will favor some aggregation of outflow within a hot boundary layer
featuring steep lapse rates.  Isolated to widely scattered severe
gusts 60-75 mph are possible, along with occasional hail with a few
of the stronger cores that develop.  It seems possible a
smaller-scale area within this broad region may focus a slightly
more concentrated severe-wind threat.  However, given the modest
large-scale forcing mechanisms and marginal deep-layer shear for
storm organization, will defer higher severe-wind probabilities for
the time being.

...Great Basin...
Modestly enhanced southwesterly mid-level flow will persist today
across the Great Basin downstream of a weak mid-level trough over
CA.  Weak to locally moderate instability is forecast via diurnal
heating.  Scattered to numerous thunderstorms are expected and some
of the stronger evaporatively cooled downdrafts will be capable of
60-75 mph gusts.  

...Northeast...
Seasonably cool mid-level temperatures are forecast today across
parts of the Northeast, with a mid-level trough expected to move
east-southeastward from Quebec into New England.  While instability
is forecast to remain fairly limited, strong west-northwesterly flow
aloft may support a risk for isolated damaging winds (50-65 mph)
with thunderstorms that develop and spread southeastward through the
afternoon.  Isolated hail may also occur with the stronger cells.

..Smith/Kerr.. 08/13/2026