Alert archive / Iowa / Flash Flood Warnings in 2008

Flash Flood Warning 44, NWS Omaha, NE

June 19, 2008Pottawattamie County, Iowa

NWS Omaha, NE issued this flash flood warning at Jun 19, 2008, 6:33 PM CDT for Pottawattamie County, Iowa. It was in force for 2 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jun 19, 2008, 6:33 PM CDT (23:33 UTC)
Expired: Jun 19, 2008, 8:49 PM CDT
In force: 2 hr
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Flood severity: None

County Pottawattamie County, IA

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.6 hours before the alert went out and 69 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1349 J/kg
Mixed-layer CIN: -35 J/kg
Mixed-layer LCL: 1135 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 46 m²/s²
0-3 km storm-relative helicity: 136 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 3.8

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Omaha, NE wrote its last area forecast discussion before this flash flood warning went out at Jun 19, 4:00 PM CDT, 2 hours 33 minutes earlier.

Area forecast discussion, Jun 19, 4:00 PM CDT, 2 hours 33 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
400 PM CDT THU JUN 19 2008

.DISCUSSION...
ONGOING SEVERE THUNDERSTORMS AND THUNDERSTORMS CHANCES THROUGH THE
PERIOD WILL BE THE FORECAST CONCERNS THIS FORECAST PACKAGE.

OF NOTE ON THE UPPER AIR CHARTS WERE TGE EMBEDDED SHORTWAVE TROFS
IN THE NW FLOW. LATEST SPC MESOANALYSIS AND RUC SOUNDINGS SHOW
LITTLE IN THE WAY OF CONVECTIVE INHIBITION WITH STEEP LOW LEVEL
LAPSE RATES. SFC BASED CAPE VALUES AT 20Z WERE AROUND 1500 TO 3000
J/KG. SHORTWAVE TROF ENERGY CONTINUES TO PASS ACROSS THE REGION
INTO THE EVENING HOURS AND WITH SUFFICIENT MOISTURE SCT TSRA WITH
SOME SEVERE THUNDERSTORMS EXPECTED TO CONTINUE INTO THE EVENING
HOURS AND THERE COULD BE SOME ISOLATED STORMS LATER TONIGHT.

THE PATTERN CONTINUES FOR FRIDAY...ALTHOUGH LOWER MOISTURE IS
AVAILABLE...ADDED LOW POPS FOR FRIDAY AFTERNOON AND CHANCE POPS
FRIDAY NIGHT. SATURDAY AFTERNOON...YET ANOTHER SHORTWAVE IN THE NW
FLOW WILL BRING A CHANCE FOR CONVECTION...THUS ADDED TO SATURDAY
AFTERNOON AND SATURDAY EVENING PERIOD. SUNDAY STILL LOOKS LIKE
HIGH PRESSURE WILL USHER IN DRY CONDITIONS. HIGHS FRIDAY THROUGH
SUNDAY SHOULD REMAIN IN THE 80S.

IN THE LONG TERM...STARTING SUNDAY NIGHT...THE MEAN MID
TROPOSPHERIC PATTERN HAS A RIDGE AROUND 105 WEST LONGITUDE AND A
TROF OVR THE GRTLKS AND OH/TN REGIO. SFC HIGH PRES HAS EAST OR
SOUTHEAST FLOW. ALTHOUGH THE RIDGE PATTERN REMAINS IN PLACE...DURING
THE DAY MONDAY...THE MID LEVEL RIDGE BEGINS TO BREAKS DOWN
TEMPORARILY WITH A TROF MOVING ACRS THE ROCKIES. THE CONVECTION
APPEARS TO BE TIED CLOSER TO THE SFC FRONT AND UPSLOPE FLOW AROUND
THE SFC HIGH OVER THE WESTERN PLAINS. THE ECWMF IS MORE
PROGRESSIVE WITH THE FRONT INTO THE FCST AREA MONDAY INTO MONDAY
NIGHT AND TUESDAY. MEANWHILE...THE GFS HOLDS OFF THE CONVECTION IN
OUR AREA WITH MCS ACRS THE NRN PLNS AND ACRS KS. HPC USED A BLEND
OF THESE MODELS ALONG WITH NCEP ENSEMBLES.

MONDAY THERE APPEARS TO BE A BETTER CHANCE OF TSRA TO THE WEST OF
THE FCST AREA...HOWEVER...SOME OF THE STORMS MAY MAKE IT FARTHER
EAST...SO BROUGHT IN LOW POPS INTO THE CWA. INCREASED CHC OF TSRA
MONDAY NIGHT INTO TUESDAY WITH THE PASSAGE OF THE MID LEVEL TROF.
THE SFC FNT IN THE VICINITY MAY BE ENOUGH TO LEAVE LOW POPS IN FOR
TUESDAY NIGHT. SINCE THE RIDGE IS NOT BROKEN DOWN ENOUGH THE FRONT
WILL NOT BE PUSHED FAR TO THE SOUTH...THE SFC FNT LINGERS IN KS/MO
AND BEGINS TO PUSH BACK THURSDAY...THUS THESE POPS MAY NEED TO BE
INCREASED.

&&

.AVIATION...
FOR TAF SITES KOMA...KLNK AND KOFK...THROUGH 20/18Z.

SCATTERED THUNDERSTORMS ARE POSSIBLE THROUGH THE EARLY EVENING. OUTSIDE
OF MVFR/IFR CIGS/VSBYS HAIL AND GUSTY WINDS IN THUNDERSTORMS...VFR
CONDITIONS SHOULD PREVAIL THROUGH FRIDAY NOON.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

ZAPOTOCNY

Hazardous weather outlook, Jun 19, 5:17 PM CDT, 1 hour 16 minutes before

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In the hours before

Local storm report, Jun 19, 5:25 PM CDT, 1 hour 8 minutes before

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Local storm report, Jun 19, 5:30 PM CDT, 1 hour 3 minutes before

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Local storm report, Jun 19, 5:47 PM CDT, 46 minutes before

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Local storm report, Jun 19, 6:02 PM CDT, 31 minutes before

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Local storm report, Jun 19, 6:20 PM CDT, 13 minutes before

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Local storm report, Jun 19, 6:22 PM CDT, 11 minutes before

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The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 18, 8:18 PM CDT	Severe Thunderstorm Warning	OAX	Washington	42 min
Jun 18, 9:14 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Cuming	31 min
Jun 19, 1:03 PM CDT	Severe Thunderstorm Warning	OAX	Jefferson	27 min
Jun 19, 1:12 PM CDT	Severe Thunderstorm Warning	OAX	Cuming, Stanton, Wayne	33 min
Jun 19, 1:38 PM CDT	Severe Thunderstorm Warning	OAX	Cuming, Stanton, Thurston, Wayne	52 min
Jun 19, 1:53 PM CDT	Severe Thunderstorm Warning	OAX	Gage	52 min
Jun 19, 2:21 PM CDT	Severe Thunderstorm Warning	OAX	Nemaha, Richardson	54 min
Jun 19, 2:33 PM CDT	Severe Thunderstorm Warning	OAX	Gage, Johnson, Pawnee	32 min
Jun 19, 2:45 PM CDT	Severe Thunderstorm Warning	OAX	Douglas, Sarpy, Saunders	45 min
Jun 19, 2:45 PM CDT	Severe Thunderstorm Warning	OAX	Madison, Stanton	45 min
Jun 19, 2:56 PM CDT	Severe Thunderstorm Warning	OAX	Antelope, Boone, Madison	49 min
Jun 19, 3:33 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Sarpy, Saunders	42 min
Jun 19, 3:41 PM CDT	Severe Thunderstorm Warning	OAX	Antelope, Boone	49 min
Jun 19, 3:55 PM CDT	Severe Thunderstorm Warning	OAX	Madison, Pierce, Stanton	50 min
Jun 19, 4:08 PM CDT	Flash Flood Warning	OAX	Madison, Pierce, Stanton	5 hr
Jun 19, 4:30 PM CDT	Severe Thunderstorm Warning	OAX	Colfax, Platte	60 min
Jun 19, 4:35 PM CDT	Severe Thunderstorm Warning	OAX	Boone	40 min
Jun 19, 4:50 PM CDT	Severe Thunderstorm Warning	OAX	Colfax	55 min
Jun 19, 5:30 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Colfax, Dodge, Saunders	37 min
Jun 19, 5:37 PM CDT	Severe Thunderstorm Warning	OAX	Cedar	38 min
Jun 19, 5:45 PM CDT	Severe Thunderstorm Warning	OAX	Antelope, Knox, Pierce	45 min
Jun 19, 5:57 PM CDT	Severe Thunderstorm Warning	OAX	Saunders	48 min
Jun 19, 6:42 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Lancaster, Saunders	33 min
Jun 19, 6:56 PM CDT	Severe Thunderstorm Warning	OAX	Douglas, Sarpy	33 min
Jun 19, 1:10 PM CDT	Severe Thunderstorm Warning	OAX	Mills, Montgomery, Pottawattamie	35 min
Jun 19, 1:42 PM CDT	Severe Thunderstorm Warning	OAX	Pottawattamie, Shelby	48 min
Jun 19, 2:43 PM CDT	Severe Thunderstorm Warning	OAX	Mills	47 min
Jun 19, 3:01 PM CDT	Severe Thunderstorm Warning	OAX	Montgomery	44 min
Jun 19, 3:30 PM CDT	Severe Thunderstorm Warning	OAX	Fremont, Mills, Montgomery, Page	45 min
Jun 19, 3:43 PM CDT	Flash Flood Warning	OAX	Mills	32 min
Jun 19, 4:00 PM CDT	Flash Flood Warning	OAX	Montgomery	60 min
Jun 19, 4:14 PM CDT	Severe Thunderstorm Warning	OAX	Fremont, Mills, Montgomery, Page	46 min
Jun 19, 4:17 PM CDT	Flash Flood Warning	OAX	Mills, Montgomery	5 hr
Jun 19, 4:33 PM CDT	Severe Thunderstorm Warning	OAX	Pottawattamie	27 min
Jun 19, 5:15 PM CDT	Severe Thunderstorm Warning	OAX	Fremont, Page	19 min

Nearby

Flash Flood Warnings in Iowa, 2008 Every flash flood warning in 2008

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.