Severe Thunderstorm Warning 261, NWS Des Moines, IA

157 
WWUS53 KDMX 281817
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
117 PM CDT TUE AUG 28 2018

IAC161-281826-
/O.CAN.KDMX.SV.W.0261.000000T0000Z-180828T1845Z/
Sac IA-
117 PM CDT TUE AUG 28 2018

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN SAC COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4263 9488 4291 9492 4286 9449 4252 9468
TIME...MOT...LOC 1816Z 199DEG 35KT 4265 9482 

$$

IAC025-151-281845-
/O.CON.KDMX.SV.W.0261.000000T0000Z-180828T1845Z/
Pocahontas IA-Calhoun IA-
117 PM CDT TUE AUG 28 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 145 PM CDT
FOR POCAHONTAS AND NORTHERN CALHOUN COUNTIES...

At 116 PM CDT, a severe thunderstorm was located 9 miles east of
Newell, or 10 miles southwest of Pocahontas, moving north at 40 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Trained weather spotters.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees.

Locations impacted include...
Pocahontas, Laurens, Pomeroy, Rolfe, Havelock, Plover and Pocahontas
Municipal Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4263 9488 4291 9492 4286 9449 4252 9468
TIME...MOT...LOC 1816Z 199DEG 35KT 4265 9482 

HAIL...1.75IN
WIND...60MPH
 
$$

Kotenberg

510 
WWUS53 KDMX 281831
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
131 PM CDT TUE AUG 28 2018

IAC025-281840-
/O.CAN.KDMX.SV.W.0261.000000T0000Z-180828T1845Z/
Calhoun IA-
131 PM CDT TUE AUG 28 2018

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN CALHOUN COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4276 9482 4290 9481 4286 9449 4262 9462
TIME...MOT...LOC 1830Z 199DEG 35KT 4279 9476 

$$

IAC151-281845-
/O.CON.KDMX.SV.W.0261.000000T0000Z-180828T1845Z/
Pocahontas IA-
131 PM CDT TUE AUG 28 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 145 PM CDT
FOR CENTRAL POCAHONTAS COUNTY...

At 130 PM CDT, a severe thunderstorm was located near Pocahontas,
moving north at 40 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Trained weather spotters.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Pocahontas, Rolfe, Havelock, Plover and Pocahontas Municipal Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4276 9482 4290 9481 4286 9449 4262 9462
TIME...MOT...LOC 1830Z 199DEG 35KT 4279 9476 

HAIL...1.00IN
WIND...60MPH
 
$$

Kotenberg

345 
WWUS53 KDMX 281839
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
139 PM CDT TUE AUG 28 2018

IAC151-281849-
/O.EXP.KDMX.SV.W.0261.000000T0000Z-180828T1845Z/
Pocahontas IA-
139 PM CDT TUE AUG 28 2018

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL POCAHONTAS COUNTY WILL
EXPIRE AT 145 PM CDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

LAT...LON 4276 9482 4290 9481 4286 9449 4262 9462
TIME...MOT...LOC 1839Z 199DEG 35KT 4285 9473 

$$

Kotenberg

Area Forecast Discussion
National Weather Service Des Moines IA
1244 PM CDT Tue Aug 28 2018

.SHORT TERM.../Today through Tonight/
Issued at 357 AM CDT Tue Aug 28 2018

At 3 AM a cold front was nosing into far northwest Iowa while aloft
several weak impulses were traversing north central and northwest
Iowa and locations to the west.  Moderate instability exists across
the northwest Iowa and locations north and west of the frontal
boundary along with sufficient deep shear to the continuation of
thunderstorms through the early morning hours.  Soundings appear to
indicate an elevated warm layer above the cold front and this is
likely where storms are initiating.  As long as the shear remains,
the threat for large hail...along with some wind threat will
persist.  Somewhat troubling is that the CAM models have recently
weakened or delayed the moving of these storms into the forecast
area until 12Z or later.  Radar imagery is not confirming this as
robust storms are just a few counties away.  Movement however does
indicate that they may just graze our northwest/northern counties.
Either way, the trend is for storms to gradually weaken as the low
level jet weakens through mid morning but not before a few severe
storms make their way across northern Iowa.

Later today and especially this afternoon and evening, instability
will be very strong along and ahead of the cold front and ongoing
storms are expected to become more widespread and intensify. Further
south, in an area of warm advection ahead of the front, additional
storms will break out mid to late morning.  It is unclear at this
point if the southern area will see much convection but if they do
develop the resultant convective debris may lessen the severe threat
at least initially.  The latest CAM models suggest that even if
storms initiate in the warm sector, there will be some clearing and
time for destabilization before the front comes through later this
afternoon and evening across the southeast.  Bottom line is that is
will be a stormy day today with a severe threat far north early this
morning then southeast during peak heating into the early evening.
QPF pretty impressive as well with over an inch forecast and higher
amounts possible in stronger storms.  Not really concerned with
flash flooding at this point as higher QPF amounts progged over D1
to D3 drought areas and with crops still capable of absorbing quite
a bit of water.

Front passes through late tonight ending the threat of storms/heavy
rainfall.  The bulk of the storms should be done by 06Z with
lingering showers and a few storms through 09Z.  Cooler and less
humid air will arrive by 12Z Wednesday.

.LONG TERM.../Wednesday through Monday/
Issued at 357 AM CDT Tue Aug 28 2018

Westerly flow aloft to be in place Wednesday with the cold front
expected to bring storms chances to the area today to have pushed to
the south of the state with an area of high pressure building into
the state. This will bring dry and cool conditions as h85 temps
falling to around +10C aloft. The area of high pressure will remain
in place into Thursday before return flow sets back up and
WAA/moisture advection returns to the state Thursday night into
Friday. A weak shortwave trough will push east through the broader
westerlies aloft and bring chances for storms back to the area
Thursday night. Broad lift will remain in place into Friday/Saturday
with a broad upper level trough across the central US and a sfc
trough axis in place across the state. This will allow for continued
chances for storms to end the week and into the weekend. The weakly
defined surface boundary to linger across the south into Sunday with
high pressure sliding across the northern portion of the state. This
should confine the better chances for precip to the central/south
late in the weekend. The boundary to then lift back to the north
into early next week with continued chances for storms with general
troughiness in the western US and westerly to southwesterly flow
aloft across Iowa.

Temperatures will initially be cooler across the state Wednesday
with the cool airmass in place aloft with highs expected to top out
in the low to mid 70s and lows in the 50s. Slightly warmer
conditions into Thursday with highs in the mid 70s to around 80,
with a return to mainly low to mid 80s expected for late this week
and into the weekend. Humidity will return to the area Friday and
beyond as dewpoints climb back into the upper 60s to lower 70s.

&&

.AVIATION.../For the 18Z TAFS through 18Z Wednesday afternoon/
Issued at 1242 PM CDT Tue Aug 28 2018

Thunderstorms will impact most sites this afternoon and into the
evening. A period of IFR cigs is possible as a cold front drops
south through the area. Winds will switch to the northwest with
the frontal passage though strong and gusty winds are possible in
vicinity of thunderstorms. Conditions will return to VFR overnight
and into Wednesday.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM...FAB
LONG TERM...Beerends
AVIATION...Donavon

Hazardous Weather Outlook
National Weather Service Des Moines IA
405 AM CDT Tue Aug 28 2018

IAZ028-037>039-048>050-059>062-070>075-081>086-092>097-291100-
Bremer-Hardin-Grundy-Black Hawk-Story-Marshall-Tama-Dallas-Polk-
Jasper-Poweshiek-Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-
Union-Clarke-Lucas-Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-
Appanoose-Davis-
405 AM CDT Tue Aug 28 2018

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Today and tonight

Strong to severe thunderstorms will be possible by mid to late
afternoon into tonight. The primary threats are damaging winds
and large hail, but an isolated tornado or two cannot be ruled
out. Locally heavy rainfall is also possible.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Periodic chances for storms return Thursday night through
Monday. The threat of severe weather is low at this time.

.SPOTTER INFORMATION STATEMENT...

Spotters are likely to be needed this afternoon into tonight.

IAZ004>007-015>017-023>027-033>036-044>047-057-058-291100-
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Sac-Calhoun-Webster-
Hamilton-Crawford-Carroll-Greene-Boone-Audubon-Guthrie-
405 AM CDT Tue Aug 28 2018

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Today and tonight

Thunderstorms are possible today into tonight. A strong to
possibly severe storm is possible early this morning. Large
hail or damaging wind gusts are the main threat early this
morning. Otherwise a strong storm may be possible with gusty
winds and small hail from late morning through this evening.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Periodic chances for storms return Thursday night through
Monday. The threat of severe weather is low at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed early this morning, otherwise
it is not anticipated.

MJB

Special Weather Statement
National Weather Service Des Moines IA
1125 AM CDT TUE AUG 28 2018

IAZ036-047-048-059-281715-
Hamilton IA-Story IA-Boone IA-Dallas IA-
1125 AM CDT TUE AUG 28 2018

...Dime to Nickel Size Hail Possible...

At 1125 AM CDT, Doppler radar was tracking a strong thunderstorm over
Perry, moving northeast at 55 mph.

Nickel size hail will be possible with this storm.

Locations impacted include...
Ames, Boone, Perry, Nevada, Madrid, Gilbert, Woodward, Iowa State
Center, Boone Speedway, Minburn, Kelley, Bouton, Luther, Perry
Municipal Airport, Boone Municipal Airport, Ledges State Park and
Ames Municipal Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4204 9341 4186 9378 4186 9382 4185 9382
      4171 9410 4182 9422 4226 9375
TIME...MOT...LOC 1625Z 231DEG 47KT 4184 9410

Kotenberg

Special Weather Statement
National Weather Service Des Moines IA
1127 AM CDT TUE AUG 28 2018

IAZ017-026-027-281715-
Cerro Gordo IA-Franklin IA-Butler IA-
1127 AM CDT TUE AUG 28 2018

...Dime to Nickel Size Hail Possible...

At 1127 AM CDT, Doppler radar was tracking a strong thunderstorm 8
miles west of Hampton, moving northeast at 45 mph.

Nickel size hail and winds in excess of 30 mph will be possible with
this storm.

Rainfall amounts up to one inch will be possible with this storm.

Locations impacted include...
Hampton, Sheffield, Rockwell, Latimer, Coulter, Alexander, Chapin,
Aredale, Dougherty, Hampton Municipal Airport and Beeds Lake State
Park.

LAT...LON 4291 9303 4291 9283 4264 9336 4274 9350
      4280 9350 4315 9302
TIME...MOT...LOC 1627Z 226DEG 41KT 4279 9336

Kotenberg

Special Weather Statement
National Weather Service Des Moines IA
1141 AM CDT TUE AUG 28 2018

IAZ024-025-034>036-281730-
Hamilton IA-Humboldt IA-Wright IA-Calhoun IA-Webster IA-
1141 AM CDT TUE AUG 28 2018

...Dime to Nickel Hail Possible...

At 1141 AM CDT, Doppler radar was tracking a strong thunderstorm 7
miles east of Manson, or 11 miles west of Fort Dodge, moving
northeast at 50 mph.

Nickel size hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Fort Dodge, Dakota City, Humboldt, Eagle Grove, Fort Dodge Regional
Airport, Big Wall Lake, Goldfield, Badger, Renwick, Barnum, Thor,
Vincent, Moorland, Woolstock, Clare, Knierim, Hardy, Frank A Gotch
State Park, Lizard Creek State Recreation Area and Eagle Grove
Municipal Airport.

LAT...LON 4260 9363 4241 9444 4250 9451 4291 9404
      4291 9397
TIME...MOT...LOC 1641Z 233DEG 43KT 4251 9439

Kotenberg

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1144 AM CDT TUE AUG 28 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1133 AM     HAIL             5 E BERKLEY             41.94N 94.01W
08/28/2018  E1.00 INCH       BOONE              IA   TRAINED SPOTTER

            3 MINUTES OF DIME TO QUARTER SIZED HAIL FROM
            11:33-11:36 AM.

&&

RD

Special Weather Statement
National Weather Service Des Moines IA
1150 AM CDT TUE AUG 28 2018

IAZ033>036-044>049-057>061-070>073-081>083-281745-
Story IA-Guthrie IA-Boone IA-Jasper IA-Polk IA-Carroll IA-
Crawford IA-Union IA-Madison IA-Cass IA-Hamilton IA-Audubon IA-
Calhoun IA-Sac IA-Webster IA-Greene IA-Adams IA-Clarke IA-Adair IA-
Marshall IA-Dallas IA-Warren IA-
1150 AM CDT TUE AUG 28 2018

...Dime to Nickel Size Hail Possible During Periods of Widespread
Thunderstorms...

At 1148 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 7 miles northwest of Denison to near Norwalk.
Movement was northeast at 55 mph.

Nickel size hail and winds in excess of 30 mph will be possible with
these storms.

Locations impacted include...
Des Moines, Ames, West Des Moines, Ankeny, Urbandale, Johnston,
Clive, Indianola, Altoona, Waukee, Boone, Carroll, Norwalk, Pleasant
Hill, Denison, Grimes, Creston, Perry, Atlantic and Nevada.

LAT...LON 4195 9567 4221 9542 4221 9532 4231 9532
      4256 9508 4256 9478 4196 9294 4098 9401
      4114 9489 4115 9490 4116 9493 4118 9510
      4121 9516 4144 9516 4150 9515 4151 9504
      4160 9504 4160 9509 4186 9509 4187 9567
TIME...MOT...LOC 1648Z 216DEG 48KT 4210 9545 4146 9373

Kotenberg

Special Weather Statement
National Weather Service Des Moines IA
1251 PM CDT TUE AUG 28 2018

IAZ005-015-016-023>026-033>038-045>049-057>060-071-281845-
Humboldt IA-Palo Alto IA-Story IA-Guthrie IA-Boone IA-Kossuth IA-
Grundy IA-Polk IA-Carroll IA-Hardin IA-Hancock IA-Hamilton IA-
Wright IA-Audubon IA-Calhoun IA-Sac IA-Webster IA-Greene IA-
Pocahontas IA-Adair IA-Marshall IA-Dallas IA-Franklin IA-
1251 PM CDT TUE AUG 28 2018

...Dime to Nickel Size Hail Possible in Widespread Area of
Storms...

At 1251 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near North Twin Lake to near Nevada. Movement
was northeast at 50 mph.

Nickel size hail and winds in excess of 30 mph will be possible with
these storms.

Locations impacted include...
Ames, Fort Dodge, Boone, Carroll, Webster City, Perry, Nevada,
Algona, Iowa Falls, Jefferson, Adel, Clarion, Eldora, Sac City,
Pocahontas, Rockwell City, Guthrie Center, Dakota City, Humboldt and
Eagle Grove.

LAT...LON 4240 9282 4150 9422 4150 9424 4149 9424
      4127 9457 4218 9509 4221 9509 4221 9511
      4236 9520 4256 9500 4256 9492 4264 9492
      4318 9437
TIME...MOT...LOC 1751Z 234DEG 45KT 4252 9472 4195 9352

Kotenberg