Alert archive / Colorado / Flash Flood Warnings in 1997

Flash Flood Warning 18, NWS Denver/Boulder, CO

July 29, 1997Logan County, Weld County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 29, 1997, 7:03 PM MDT for Logan County, Weld County, Colorado. It was in force for 72 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jul 29, 1997, 7:03 PM MDT (01:03 UTC)
Expired
Jul 29, 1997, 8:15 PM MDT
In force
72 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties

Counties Logan County, CO, Weld County, CO

The radar

The Cheyenne radar (KCYS), 105 km from the middle of the area, began a volume at 01:03 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

Denver, CO (KDNR), launched 00:00Z, 1.1 hours before the alert went out and 96 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-pSkew-T log-p diagram, Denver, CO at 00:00Z on 1997-07-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 154 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 00:00Z on 1997-07-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 8 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
154 J/kg
Mixed-layer CIN
-82 J/kg
Mixed-layer LCL
1447 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
8 m²/s²
0-3 km storm-relative helicity
67 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KDEN 300105 COR
FFWDEN
COC123-075-300215-

FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
703 PM MDT TUE JUL 29 1997

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A FLASH FLOOD 
WARNING EFFECTIVE UNTIL 815 PM MDT FOR PEOPLE IN THE FOLLOWING 
NORTHEAST COLORADO COUNTIES

     EXTREME NORTHEASTERN WELD AND NORTHWESTERN LOGAN

     INCLUDING THE FOLLOWING LOCATIONS
         WESTPLAINS AND THE PAWNEE NATIONAL GRASSLANDS 

AT 655 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
TORRENTIAL RAINFALL OVER THE PAWNEE NATIONAL GRASSLANDS IN EXTREME 
NORTHEAST WELD COUNTY.  DOPPLER RADAR HAS ESTIMATES OF 2 TO 2 1/2 
INCHES OF RAIN IN THIS AREA IN THE PAST HOUR.  

ALTHOUGH THE HEAVY RAIN WAS FALLING IN UNINHABITED GRASSLAND AREAS 
SEVERAL SMALL STREAMS AND CREEKS ORIGINATING IN THE AREA FLOW 
SOUTHEAST INTO NORTHWEST LOGAN COUNTY.  STREAMS IN DANGER OF FLASH 
FLOODING INCLUDE COTTONWOOD...SPRING...TWOMILE AND CEDAR CREEKS.   
HIGH WATERS FLOWING DOWN TWOMILE AND CEDAR CREEKS FEED INTO STERLING 
RESERVOIR...12 MILES NORTH OF STERLING.  

ADDITIONAL RAINFALL AMOUNTS RANGING FROM 1 TO 2 INCHES ARE POSSIBLE 
IN THE WARNING AREA BY 8 PM MDT.  

EXCESSIVE RUNOFF FROM THIS STORM WILL LIKELY CAUSE FLOODING OF SMALL 
CREEKS AND STREAMS...COUNTRY ROADS...NORMALLY DRY WASHES AND 
ARROYOS...AS WELL AS FARMLAND ALONG THE BANKS OF CREEKS AND STREAMS.
BE PREPARED TO MOVE QUICKLY TO HIGH GROUND IF FLOODING OCCURS. 

BAKER

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.

In the hours before

Special weather statement, Jul 29, 6:15 PM MDT, 48 minutes before
COZ046-049-300145-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
615 PM MDT TUE JUL 29 1997

...WEATHER CONDITIONS RIGHT FOR HEAVY RAIN PRODUCING THUNDERSTORMS
IN NORTHERN LINCOLN AND WASHINGTON COUNTIES...

A LINE OF THUNDERSTORMS MOVING EAST INTO VERY MOIST AND UNSTABLE AIR
LYING ACROSS NORTHERN LINCOLN AND WASHINGTON COUNTINES IN NORTHEAST
COLORADO WILL LIKELY FUEL HEAVY RAIN PRODUCING THUNDERSTORMS BETWEEN
620 AND 745 PM MDT.

NATIONAL WEATHER SERVICE DOPPLER RADAR AS OF 600 PM WAS ALREADY
INDICATED NEW THUNDERSTORM DEVELOPMENT BETWEEN AKRON AND ANTON.
THE POTENTIAL EXISTS FOR RAINFALL RATES OF 1 TO 3 INCHES PER HOUR
FROM THESE THUNDERSTORMS MOVE EAST ACROSS WASHINGTON AND NORTHERN
LINCOLN COUNTIES AT 10 TO 15 MILES PER HOUR.

HEAVY RAIN FALLING ON ALREADY SATURATED GROUND MAY CAUSE FLOODING OF DRY
CREEK BEDS...FIELDS...DITCHES AND LOW LANDS.  LOW LYING ROADS MAY
ALSO BECOME SUBMERGED OR WASHED OUT BY FLOOD WATERS. BE PREPARED TO
MOVE QUICKLY TO HIGH GROUND IF HIGH WATERS ARE OBSERVED.

NORTHEAST COLORADO REMAINS UNDER A FLASH FLOOD WATCH UNTIL MIDNIGHT
MDT TONIGHT.

BAKER
Special weather statement, Jul 29, 6:15 PM MDT, 48 minutes before
COZ046-049-300145-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
615 PM MDT TUE JUL 29 1997

...WEATHER CONDITIONS RIGHT FOR HEAVY RAIN PRODUCING THUNDERSTORMS
IN NORTHERN LINCOLN AND WASHINGTON COUNTIES...

A LINE OF THUNDERSTORMS MOVING EAST INTO VERY MOIST AND UNSTABLE AIR
LYING ACROSS NORTHERN LINCOLN AND WASHINGTON COUNTIES IN NORTHEAST
COLORADO WILL LIKELY FUEL HEAVY RAIN PRODUCING THUNDERSTORMS BETWEEN
620 AND 745 PM MDT.

NATIONAL WEATHER SERVICE DOPPLER RADAR AS OF 600 PM WAS ALREADY
INDICATED NEW THUNDERSTORM DEVELOPMENT BETWEEN AKRON AND ANTON.
THE POTENTIAL EXISTS FOR RAINFALL RATES OF 1 TO 3 INCHES PER HOUR
FROM THESE THUNDERSTORMS MOVE EAST ACROSS WASHINGTON AND NORTHERN
LINCOLN COUNTIES AT 10 TO 15 MILES PER HOUR.

HEAVY RAIN FALLING ON ALREADY SATURATED GROUND MAY CAUSE FLOODING OF DRY
CREEK BEDS...FIELDS...DITCHES AND LOW LANDS.  LOW LYING ROADS MAY
ALSO BECOME SUBMERGED OR WASHED OUT BY FLOOD WATERS. BE PREPARED TO
MOVE QUICKLY TO HIGH GROUND IF HIGH WATERS ARE OBSERVED.

NORTHEAST COLORADO REMAINS UNDER A FLASH FLOOD WATCH UNTIL MIDNIGHT
MDT TONIGHT.

BAKER
Special weather statement, Jul 29, 6:38 PM MDT, 25 minutes before
COZ041-044-045-300100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
638 PM MDT TUE JUL 29 1997

...SMALL STREAM ADVISORY HAS EXPIRED...

THE SMALL STREAM FLOOD ADVISORY FOR SOUTHEASTERN DOUGLAS...EASTERN
ADAMS AND ARAPAHOE...AND SOUTHWEST MORGAN COUNTIES IN NORTHEAST
COLORADO HAS EXPIRED AS OF 615 PM MDT.

AT 635 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THAT
MOST OF THE THUNDERSTORM ACTIVITY HAD MOVED EAST OF THESE COUNTIES
NO LONGER POSING A THREAT FOR FLASH FLOODING.  HOWEVER...
THUNDERSTORMS MAY REFORM IN THESE AREAS LATER THIS EVENING AS THE
ATMOSPHERE REMAINS VERY MOIST AND UNSTABLE.

A FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL MIDNIGHT MDT FOR ALL OF
NORTHEAST COLORADO.

BAKER
Special weather statement, Jul 29, 6:38 PM MDT, 25 minutes before
COZ041-044-045-300100-

SPECIAL WEATHER STATEMENT      ...CORRECTION FOR MISSING WORD...
NATIONAL WEATHER SERVICE DENVER CO
638 PM MDT TUE JUL 29 1997

...SMALL STREAM FLOOD ADVISORY HAS EXPIRED...

THE SMALL STREAM FLOOD ADVISORY FOR SOUTHEASTERN DOUGLAS...EASTERN
ADAMS AND ARAPAHOE...AND SOUTHWEST MORGAN COUNTIES IN NORTHEAST
COLORADO HAS EXPIRED AS OF 615 PM MDT.

AT 635 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THAT
MOST OF THE THUNDERSTORM ACTIVITY HAD MOVED EAST OF THESE COUNTIES
NO LONGER POSING A THREAT FOR FLASH FLOODING.  HOWEVER...
THUNDERSTORMS MAY REFORM IN THESE AREAS LATER THIS EVENING AS THE
ATMOSPHERE REMAINS VERY MOIST AND UNSTABLE.

A FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL MIDNIGHT MDT FOR ALL OF
NORTHEAST COLORADO.

BAKER
Special weather statement, Jul 29, 6:39 PM MDT, 24 minutes before
COZ041-044-045-300100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
638 PM MDT TUE JUL 29 1997

...SMALL STREAM ADVISORY HAS EXPIRED...

THE SMALL STREAM FLOOD ADVISORY FOR SOUTHEASTERN DOUGLAS...EASTERN
ADAMS AND ARAPAHOE...AND SOUTHWEST MORGAN COUNTIES IN NORTHEAST
COLORADO HAS EXPIRED AS OF 615 PM MDT.

AT 635 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THAT
MOST OF THE THUNDERSTORM ACTIVITY HAD MOVED EAST OF THESE COUNTIES
NO LONGER POSING A THREAT FOR FLASH FLOODING.  HOWEVER...
THUNDERSTORMS MAY REFORM IN THESE AREAS LATER THIS EVENING AS THE
ATMOSPHERE REMAINS VERY MOIST AND UNSTABLE.

A FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL MIDNHIGHT MDT FOR ALL OF
NORTHEAST COLORADO.

BAKER
Special weather statement, Jul 29, 6:40 PM MDT, 23 minutes before
COZ041-044-045-300100-

SPECIAL WEATHER STATEMENT      ...CORRECTION FOR MISSING WORD...
NATIONAL WEATHER SERVICE DENVER CO
638 PM MDT TUE JUL 29 1997

...SMALL STREAM FLOOD ADVISORY HAS EXPIRED...

THE SMALL STREAM FLOOD ADVISORY FOR SOUTHEASTERN DOUGLAS...EASTERN
ADAMS AND ARAPAHOE...AND SOUTHWEST MORGAN COUNTIES IN NORTHEAST
COLORADO HAS EXPIRED AS OF 615 PM MDT.

AT 635 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THAT
MOST OF THE THUNDERSTORM ACTIVITY HAD MOVED EAST OF THESE COUNTIES
NO LONGER POSING A THREAT FOR FLASH FLOODING.  HOWEVER...
THUNDERSTORMS MAY REFORM IN THESE AREAS LATER THIS EVENING AS THE
ATMOSPHERE REMAINS VERY MOIST AND UNSTABLE.

A FLANSH FLOOD WATCH REMAINS IN EFFECT UNTIL MIDNIGHT MDT FOR ALL OF
NORTHEAST COLORADO.

BAKER

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 29, 6:24 PM MDTFlash Flood WarningBOUElbert96 min
Jul 29, 7:59 PM MDTFlash Flood WarningBOUElbert, Lincoln2 hr
Jul 29, 8:00 PM MDTFlash Flood WarningBOULogan, Weld90 min
Jul 29, 8:15 PM MDTFlash Flood WarningBOULarimer3 hr
Jul 29, 8:20 PM MDTFlash Flood WarningBOUMorgan55 min
Jul 29, 9:20 PM MDTFlash Flood WarningBOUMorgan40 min
Jul 29, 9:40 PM MDTFlash Flood WarningBOULogan, Weld80 min
Jul 29, 9:55 PM MDTFlash Flood WarningBOUElbert, Lincoln2 hr
Jul 29, 10:10 PM MDTFlash Flood WarningBOUMorgan50 min
Jul 29, 10:50 PM MDTFlash Flood WarningBOULogan, Morgan, Washington, Weld2 hr
Jul 29, 11:26 PM MDTFlash Flood WarningBOUElbert, Lincoln2 hr
Jul 30, 2:25 PM MDTFlash Flood WarningBOULarimer110 min
Jul 30, 3:25 PM MDTFlash Flood WarningBOUBoulder, Clear Creek, Gilpin, Jefferson2 hr
Jul 30, 4:05 PM MDTFlash Flood WarningBOUBoulder, Jefferson115 min
Jul 30, 4:05 PM MDTSevere Thunderstorm WarningBOUBoulder, Jefferson115 min
Jul 30, 4:30 PM MDTFlash Flood WarningBOULogan14 hr

Nearby

Flash Flood Warnings in Colorado, 1997Every flash flood warning in 1997

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.