Alert archive / Iowa / Flash Flood Warnings in 1999

Flash Flood Warning 3, NWS Omaha, NE

May 16, 1999Montgomery County, Iowa

NWS Omaha, NE issued this flash flood warning at May 16, 1999, 7:37 PM CDT for Montgomery County, Iowa. It was in force for 6 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: May 16, 1999, 7:37 PM CDT (00:37 UTC)
Expired: May 17, 1999, 1:40 AM CDT
In force: 6 hr
Issued by: NWS Omaha, NE
Area: Whole counties

County Montgomery County, IA

The radar

The Omaha radar (KOAX), 106 km from the middle of the area, began a volume at 00:39 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 0.6 hours before the alert went out and 107 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: 996 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 781 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: -12 m²/s²
0-3 km storm-relative helicity: 261 m²/s²
Significant tornado parameter: 1.3
Supercell composite: 10.2

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 May 16, 3:00 PM CDT, 4 hours 37 minutes earlier.

Area forecast discussion, May 16, 3:00 PM CDT, 4 hours 37 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
300 PM CDT SUN MAY 16 1999

DISCUSSION WILL BE CUT SHORT BECAUSE OF SVR WX.  CDFNT CONTS TO PUSH
E INTO VERY UNSTABLE ATMOSPHERE.  CAPES IN EXCESS OF 4000 J/KG WITH
SFC DEWPTS IN THE LOWER 70S.  WET BULB ZERO HEIGHTS LOW ENOUGH FOR
SOME SGFNT SIZE HAIL.

EXPECT PCPN TO CONT ON MON...ENDING FROM W TO E.  PCPN ACROSS NERN NE
MAINLY OF SHOWER TYPE...WITH ISOLD TSTMS.  STILL SOME TSTMS MON IN
SERN NE AND SWRN IA...SPCLY BEFORE EARLY AFTN.  TEMPS COOLER BEHIND
THE FNT MON...GENLY 60S.  SKIES SHOULD CLEAR OUT MON NGT AFTER SOME
LINGER SHOWERS SWRN IA.  THEN MOSTLY SUNNY FOR TUE.  FIRST DRAFT OF
WORK ZONES COMING OUT SHORTLY.  TEMP FCSTS GENLY WITHIN 5 DEGREES OF
NGM MOS.

.OMA...NONE
MILLER

In the hours before

Special weather statement, May 16, 2:55 PM CDT, 4 hours 42 minutes before

NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-088>093-
IAZ043-055-056-069-079-080-090-091-171200-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
255 PM CDT SUN MAY 16 1999

...SEVERE WEATHER OUTLOOK FOR EASTERN NEBRASKA AND SOUTHWEST IOWA...

A TORNADO WATCH HAS BEEN ISSUED FOR PARTS OF EASTERN NEBRASKA AND
SOUTHWEST IOWA.  DUE TO THE DEGREE OF INSTABILITY AND AMOUNT OF
LOW LEVEL MOISTURE...ALL THUNDERSTORMS SHOULD BE MONITORED CLOSELY.
LARGE HAIL IS LIKELY IN SOME OF THE STORMS...AND A FEW TORNADOES
ARE POSSIBLE.

THE RISK OF SEVERE WEATHER IS HIGHEST TO THE SOUTHEAST OF A LINE
FROM DAVID CITY TO FREMONT AND ONAWA IOWA.

MILLER

Special weather statement, May 16, 2:55 PM CDT, 4 hours 42 minutes before

NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-088>093-
IAZ043-055-056-069-079-080-090-091-171200-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
255 PM CDT SUN MAY 16 1999

...SEVERE WEATHER OUTLOOK FOR EASTERN NEBRASKA AND SOUTHWEST IOWA...

A TORNADO WATCH HAS BEEN ISSUED FOR PARTS OF EASTERN NEBRASKA AND
SOUTHWEST IOWA.  DUE TO THE DEGREE OF INSTABILITY AND AMOUNT OF
LOW LEVEL MOISTURE...ALL THUNDERSTORMS SHOULD BE MONITORED CLOSELY.
LARGE HAIL IS LIKELY IN SOME OF THE STORMS...AND A FEW TORNADOES
ARE POSSIBLE.

THE RISK OF SEVERE WEATHER IS HIGHEST TO THE SOUTHEAST OF A LINE
FROM DAVID CITY TO FREMONT AND ONAWA IOWA.

MILLER

Special weather statement, May 16, 4:30 PM CDT, 3 hours 7 minutes before

NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-088>093-
IAZ043-055-056-069-079-080-090-091-171200-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
430 PM CDT SUN MAY 16 1999

...SEVERE WEATHER OUTLOOK FOR EASTERN NEBRASKA AND SOUTHWEST IOWA...

A TORNADO WATCH REMAINS IN EFFECT FOR PARTS OF EASTERN NEBRASKA AND
SOUTHWEST IOWA UNTIL 9 PM.  DUE TO THE DEGREE OF INSTABILITY AND THE
AMOUNT LOW LEVEL MOISTURE...ALL THUNDERSTORMS SHOULD BE MONITORED.
THIS IS A DANGEROUS SITUATION FOR SOUTHWEST IOWA...AS WELL AS FOR
EAST CENTRAL AND SOUTHEAST NEBRASKA.  VERY LARGE HAIL...LARGER THAN
THE SIZE OF GOLFBALLS...DAMAGING WINDS AND A FEW TORNADOES ARE
POSSIBLE.

THROUGH 9 PM THE MOST LIKELY AREA FOR SEVERE WEATHER IS SOUTHEAST
OF LINE FROM WILBER TO FREMONT AND ONAWA IOWA.

MILLER

Special weather statement, May 16, 4:30 PM CDT, 3 hours 7 minutes before

NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-088>093-
IAZ043-055-056-069-079-080-090-091-171200-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
430 PM CDT SUN MAY 16 1999

...SEVERE WEATHER OUTLOOK FOR EASTERN NEBRASKA AND SOUTHWEST IOWA...

A TORNADO WATCH REMAINS IN EFFECT FOR PARTS OF EASTERN NEBRASKA AND
SOUTHWEST IOWA UNTIL 9 PM.  DUE TO THE DEGREE OF INSTABILITY AND THE
AMOUNT LOW LEVEL MOISTURE...ALL THUNDERSTORMS SHOULD BE MONITORED.
THIS IS A DANGEROUS SITUATION FOR SOUTHWEST IOWA...AS WELL AS FOR
EAST CENTRAL AND SOUTHEAST NEBRASKA.  VERY LARGE HAIL...LARGER THAN
THE SIZE OF GOLFBALLS...DAMAGING WINDS AND A FEW TORNADOES ARE
POSSIBLE.

THROUGH 9 PM THE MOST LIKELY AREA FOR SEVERE WEATHER IS SOUTHEAST
OF LINE FROM WILBER TO FREMONT AND ONAWA IOWA.

MILLER

Special weather statement, May 16, 6:08 PM CDT, 1 hour 29 minutes before

IAZ043-055-NEZ034-045-051>053-066-078-088-089-162330-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
608 PM CDT SUN MAY 16 1999

...PART OF TORNADO WATCH NUMBER 272 HAS BEEN CANCELLED...

THE FOLLOWING COUNTIES IN EASTERN NEBRASKA ARE NO LONGER IN
THE TORNADO WATCH WHICH WAS ISSUED EARLIER TODAY...BURT...
WASHINGTON...SAUNDERS...DOUGLAS...SARPY...LANCASTER...
SALINE...JEFFERSON AND GAGE.  THE FOLLOWING COUNTIES IN IOWA
HAVE ALSO BEEN REMOVED FROM THE WATCH...MONONA AND HARRISON.

THE REMAINDER OF THE WATCH REMAINS IN EFFECT FOR PARTS OF
SOUTHEAST NEBRASKA AND SOUTHWEST IOWA.

MILLER

The office that day

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

Issued	Product	Office	Counties	Lasted
May 16, 7:01 PM CDT	Severe Thunderstorm Warning	OAX	Nemaha, Richardson	49 min
May 16, 9:25 PM CDT	Tornado Warning	OAX	Nemaha	35 min
May 16, 9:35 PM CDT	Severe Thunderstorm Warning	OAX	Otoe	35 min
May 16, 10:14 PM CDT	Severe Thunderstorm Warning	OAX	Nemaha	36 min
May 16, 10:29 PM CDT	Severe Thunderstorm Warning	OAX	Otoe	36 min
May 16, 11:04 PM CDT	Severe Thunderstorm Warning	OAX	Fremont	31 min

Nearby

Flash Flood Warnings in Iowa, 1999 Every flash flood warning in 1999

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; radar from the NEXRAD Level II archive.