Flash Flood Warning 17, NWS Des Moines, IA

635 
WGUS73 KDMX 040053
FFSDMX

Flash Flood Statement
National Weather Service Des Moines IA
753 PM CDT Wed Jul 3 2019

IAC015-169-040300-
/O.CON.KDMX.FF.W.0017.000000T0000Z-190704T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Story IA-Boone IA-
753 PM CDT Wed Jul 3 2019

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1000 PM CDT FOR
STORY AND NORTHEASTERN BOONE COUNTIES...

At 749 PM CDT, local law enforcement reported flooding still 
ongoing. Up to three inches of rain had fallen from earlier 
thunderstorms in the warned area. Numerous roads have been impacted 
across Story County.

Some locations that will experience flooding include...
Ames, Nevada, Story City, Roland, Gilbert, Iowa State Center, Colo,
Zearing, McCallsburg and Ames Municipal Airport.

This includes Interstate 35 between mile markers 111 and 126.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

&&

LAT...LON 4199 9383 4221 9383 4221 9323 4199 9323

$$

Hahn

572 
WGUS73 KDMX 040301
FFSDMX

Flash Flood Statement
National Weather Service Des Moines IA
1001 PM CDT Wed Jul 3 2019

IAC015-169-040310-
/O.EXP.KDMX.FF.W.0017.000000T0000Z-190704T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Story IA-Boone IA-
1001 PM CDT Wed Jul 3 2019

...THE FLASH FLOOD WARNING FOR STORY AND NORTHEASTERN BOONE COUNTIES
HAS EXPIRED...

The Flash Flood Warning has been replaced with a new Areal Flood 
Warning. The new Areal Flood Warning will remain in effect through 
tonight due to ongoing flooding impacts along area roadways.

LAT...LON 4199 9383 4221 9383 4221 9323 4199 9323

$$

Hahn

Area Forecast Discussion
National Weather Service Des Moines IA
310 PM CDT Wed Jul 3 2019

.DISCUSSION.../Tonight through Wednesday/
Issued at 308 PM CDT Wed Jul 3 2019

The primary focus for the forecast is the potential for heavy
rainfall and isolated severe storms beginning this afternoon. A warm
front has lifted into central Iowa this afternoon and is approaching
Interstate 80. The main focus for storms is expected within the
Highway 20 and Interstate 80 corridor, which is along and north of
the warm front. MLCAPE across this region is in excess of 2500 J/kg
though deep layer shear remains quite weak at 20 kts or less. Low
level shear remains quite weak as well at 10 kts or less. 0-3 km
CAPE is high at 150 J/kg with some surface vorticity available north
of the warm front. This will help maximize low level stretching
potential so cannot rule out an isolated tornado especially early
this afternoon before cold pool development occurs. Microburst are
also possible and 0-3 km theta-e differences > 30 do support cold
pool surges. Quarter sized hail is possible with any initial strong
updrafts though the damaging wind threat is the primary severe
threat.

Heavy rainfall is the other concern and have issued a Flash Flood
Watch for portions of central Iowa for the potential for very heavy
rainfall locally and due to locally heavy rainfall pockets over the
past 24 hrs. An area of heavy rainfall is now developing over Greene
and Boone Counties.  PWAT values in excess of 2 inches and warm
cloud depths approaching 14 kft at times will lead to very efficient
rainfall producing storms. In addition to slow moving storms and
repeated storms will lead to the heavy rain potential. Rainfall
amounts of 2 to 4 inches are possible in the localized areas and
rainfall rates with individual storms will exceed 2 inches per hours
leading to accelerated ponding and pooling of water. The bulk of the
activity is expected to be done by 06z, therefore the watch will end
then.

A few isolated storms are possible through the day on Thursday. A
short wave lifting through the flow may cause redevelopment over
southern Iowa in the afternoon in addition other storms may develop
along a weak boundary moving into northwest Iowa during the
afternoon. Again, isolated severe storms and locally heavy rainfall
will be possible but convection is not expected to be as vigorous as
today.

A stronger shortwave will arrive on Friday and bring renewed
convection. Another round of strong storms will be possibly from
Friday into Saturday until the system and boundary finally pass to
the south. Will certainly be monitoring this period for the heavy
rain potential considering potential heavy rain ongoing recently. A
pattern change will occur Sunday through Tuesday with the transition
from zonal flow to a building ridge into mid next week. This will
bring warm and humid weather back to the stat

&&

.AVIATION.../For the 18Z TAFS through 18Z Thursday afternoon/
Issued at 1200 PM CDT Wed Jul 3 2019

The main aviation hazard through the period will be scattered
thunderstorms and changing wind directions and speeds with
associated outflow. The greatest chances to impact sites will be
from 21z to 03z. Otherwise VFR conditions are expected between
storms.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 1 AM CDT Thursday for IAZ033>036-044>050-
057>062.

&&

DISCUSSION...Donavon
AVIATION...Donavon

Hazardous Weather Outlook
National Weather Service Des Moines IA
230 PM CDT Wed Jul 3 2019

IAZ004>007-015>017-023>028-037>039-070>075-081>086-092>097-041100-
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Hardin-Grundy-
Black Hawk-Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union-
Clarke-Lucas-Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-
Appanoose-Davis-
230 PM CDT Wed Jul 3 2019

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...This afternoon and tonight

Scattered thunderstorms will affect the area through this evening
and into tonight. Locally heavy rainfall is expected and a few
storms could be severe. Large hail and damaging winds would be the
primary severe weather threats, but an isolated tornado cannot be
ruled out.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Thunderstorm chances will persist intermittently through the
remainder of the week. Isolated severe storms and locally heavy
rain will remain possible at times.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is possible at times through the week.

IAZ033>036-044>050-057>062-041100-
Sac-Calhoun-Webster-Hamilton-Crawford-Carroll-Greene-Boone-Story-
Marshall-Tama-Audubon-Guthrie-Dallas-Polk-Jasper-Poweshiek-
230 PM CDT Wed Jul 3 2019

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...This afternoon and tonight

A Flash Flood Watch is in effect for the area. Please refer to the
National Weather Service website at weather.gov/desmoines for
further details.

Scattered thunderstorms will affect the area through this evening
and into tonight. Locally heavy rainfall is expected and a few
storms could be severe. Large hail and damaging winds would be the
primary severe weather threats, but an isolated tornado cannot be
ruled out.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Thunderstorm chances will persist intermittently through the
remainder of the week. Isolated severe storms and locally heavy
rain will remain possible at times.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is possible at times through the week.

Lee

Special Weather Statement
National Weather Service Des Moines IA
301 PM CDT Wed Jul 3 2019

IAZ035>038-045>049-057>061-070>073-032215-
Webster-Hamilton-Hardin-Grundy-Carroll-Greene-Boone-Story-
Marshall-Audubon-Guthrie-Dallas-Polk-Jasper-Cass-Adair-Madison-
Warren-
Including the cities of Fort Dodge, Webster City, Iowa Falls,
Eldora, Ackley, Grundy Center, Reinbeck, Conrad, Dike, Wellsburg,
Carroll, Jefferson, Boone, Ames, Marshalltown, Audubon, Exira,
Guthrie Center, Panora, Bayard, Casey, Perry, Waukee, Adel,
Des Moines, Newton, Atlantic, Greenfield, Stuart, Adair,
Fontanelle, Winterset, Earlham, Indianola, Norwalk, and Carlisle
301 PM CDT Wed Jul 3 2019

...Strong Thunderstorms Possible over Central Iowa into the Early
Evening Hours...

Strong to severe thunderstorms have developed over west central
Iowa this afternoon and are expected to slowly move eastward
across the heart of Iowa into the early evening hours. Some of the
stronger storms may produce wind gusts to 50 mph or more as well
as hail.

Locally heavy rains are expected as well which may produce
rainfall rates of one to two inches per hour over small areas.
This may lead to low visibilities, ponding water on roads and
rapid rises in small streams and creeks.

People planning or participating in outdoor activities should
monitor weather conditions closely and be prepared to seek shelter
if threatening weather approaches.

Small

Special Weather Statement
National Weather Service Des Moines IA
345 PM CDT Wed Jul 3 2019

IAZ024-025-035-032200-
Humboldt-Wright-Webster-
Including the cities of Humboldt, Eagle Grove, Clarion, Belmond,
and Fort Dodge
345 PM CDT Wed Jul 3 2019

...CONDITIONS ARE FAVORABLE FOR FUNNEL CLOUDS...

Current atmospheric conditions support the development of funnel
clouds. Usually, these funnel clouds can form from showers and
weak thunderstorms. These funnels are normally brief, drop only
a few hundred feet from the cloud base, and rarely become a
tornado or cause damage. However, if one is spotted, please
immediately report it to the National Weather Service. If a tornado
warning would become necessary, take appropriate action.

Funnel clouds have recently been reported over Webster and southern
Humboldt Counties.

Small