Alert archive / Colorado / Flash Flood Warnings in 1998
Flash Flood Warning 8, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at Jul 25, 1998, 4:29 PM MDT for Logan County, Colorado. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.
The area
The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.
The facts
- Issued
- Jul 25, 1998, 4:29 PM MDT (22:29 UTC)
- Expired
- Jul 25, 1998, 7:30 PM MDT
- In force
- 3 hr
- Issued by
- NWS Denver/Boulder, CO
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
County Logan County, CO
The radar
The Cheyenne radar (KCYS), 165 km from the middle of the area, began a volume at 22:31 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 12:00Z, 10.5 hours before the alert went out and 110 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.
- Mixed-layer CAPE
- 114 J/kg
- Mixed-layer CIN
- -131 J/kg
- Mixed-layer LCL
- 1134 m above ground
- 0-6 km bulk shear
- 4 kt
- 0-1 km storm-relative helicity
- -29 m²/s²
- 0-3 km storm-relative helicity
- -47 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000
TTAA00 KDEN 252229
FFWDEN
COC075-260230-
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
429 PM MDT SAT JUL 25 1998
THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A
* FLASH FLOOD WARNING FOR...
NORTHEASTERN LOGAN COUNTY IN NORTHEAST COLORADO
* UNTIL 730 PM MDT
* AT 419 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
VERY HEAVY RAIN 2 MILES WEST OF CROOK...OR ABOUT 24 MILES NORTHEAST
OF STERLING. THE THUNDERSTORM WAS NEARLY STATIONARY.
LOCATIONS IN THE WARNING INCLUDE...CROOK AND TWIN BUTTES
THIS WARNING IS IN ADDITION TO A SEVERE THUNDERSTORM WARNING IN
EFFECT UNTIL 445 PM.
NATIONAL WEATHER SERVICE DOPPLER RADAR ESTIMATED 3 INCHES OF RAIN
BETWEEN 350 PM AND 420 PM. AN ADDITIONAL 3 TO 5 INCHES OF RAIN MAY
OCCUR IN THIS AREA THROUGH 6 PM.
A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS
IMMINENT. MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES. DO NOT
ATTEMPT TO CROSS BRIDGES...DIPS...OR OTHER LOW SPOTS IF WATER COVERS
THE ROADWAY. NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL
ONE...ON FOOT. TO ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.
LAT...LON 4072 10300 4072 10268 4098 10268 4099 10306
DANKERSvWhat 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 25, 11:38 AM MDT, 4 hours 51 minutes before
COZ030-032>050-260600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER COLORADO 1140 AM MDT TUE JUL 7 1998 THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES ADAMS ARAPAHOE BOULDER CLEAR CREEK DENVER DOUGLAS ELBERT GILPIN GRAND JACKSON JEFFERSON LARIMER LINCOLN LOGAN MORGAN PARK PHILLIPS SEDGWICK SUMMIT WASHINGTON WELD SYNOPSIS: VERY LITTLE HAS CHANGED IN 24 HOURS. A VERY MOIST AIRMASS RESIDES OVER EASTERN COLORADO WITH A VERY WEAK WIND PATTERN THROUGH THE ATMOSPHERE. THE RESULT WILL BE ANOTHER ROUND OF WIDESPREAD SLOW MOVING THUNDERSTORMS THIS AFTERNOON AND EVENING. THE MOST LIKELY FOCUS FOR THESE STORMS WILL BE A WIND CONVERGENCE BOUNDARY...WHICH WILL EXTEND FROM NORTHEAST WELD COUNTY TO EASTERN ELBERT COUNTY EARLY THIS AFTERNOON...AND SLIGHTLY FURTHER WEST BY EARLY EVENING. AS WE HAVE SEEN IN THE PAST FEW DAYS...OUTFLOW BOUNDARIES FROM THE STORMS WILL BE CRITICAL IN HOW STORMS DEVELOP AND MOVE THROUGH THE AFTERNOON AND EVENING. TORRENTIAL RAINFALL RATES ARE AGAIN POSSIBLE...IN THE HEART OF SOME STORMS RAINFALL RATES OF 2.5 INCHES AN HOUR ARE POSSIBLE...WITH 3 TO 4 INCHES POSSIBLE IN AN HOUR. WE WILL MOST LIKELY ISSUE ANOTHER FLASH FLOOD WATCH LATER THIS AFTERNOON...AS WE BETTER DEFINE THE AREA TO BE IMPACTED BY THE HEAVY RAIN. WE DO NOT EXPECT TO ACTIVATE SPOTTER NETWORKS...BUT ASK SPOTTERS TO REPORT ANY FLOODING PROBLEMS...AND IF RAIN GAUGES ARE AVAILABLE...ANY RAINFALL AMOUNTS IN EXCESS OF 1 INCH. RTG
Special weather statement, Jul 25, 11:40 AM MDT, 4 hours 49 minutes before
COZ030-032>050-260600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER COLORADO 1140 AM MDT SAT JUL 25 1998 ...CORRECTED DATE... THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES ADAMS ARAPAHOE BOULDER CLEAR CREEK DENVER DOUGLAS ELBERT GILPIN GRAND JACKSON JEFFERSON LARIMER LINCOLN LOGAN MORGAN PARK PHILLIPS SEDGWICK SUMMIT WASHINGTON WELD SYNOPSIS: VERY LITTLE HAS CHANGED IN 24 HOURS. A VERY MOIST AIRMASS RESIDES OVER EASTERN COLORADO WITH A VERY WEAK WIND PATTERN THROUGH THE ATMOSPHERE. THE RESULT WILL BE ANOTHER ROUND OF WIDESPREAD SLOW MOVING THUNDERSTORMS THIS AFTERNOON AND EVENING. THE MOST LIKELY FOCUS FOR THESE STORMS WILL BE A WIND CONVERGENCE BOUNDARY...WHICH WILL EXTEND FROM NORTHEAST WELD COUNTY TO EASTERN ELBERT COUNTY EARLY THIS AFTERNOON...AND SLIGHTLY FURTHER WEST BY EARLY EVENING. AS WE HAVE SEEN IN THE PAST FEW DAYS...OUTFLOW BOUNDARIES FROM THE STORMS WILL BE CRITICAL IN HOW STORMS DEVELOP AND MOVE THROUGH THE AFTERNOON AND EVENING. TORRENTIAL RAINFALL RATES ARE AGAIN POSSIBLE...IN THE HEART OF SOME STORMS RAINFALL RATES OF 2.5 INCHES AN HOUR ARE POSSIBLE...WITH 3 TO 4 INCHES POSSIBLE IN AN HOUR. WE WILL MOST LIKELY ISSUE ANOTHER FLASH FLOOD WATCH LATER THIS AFTERNOON...AS WE BETTER DEFINE THE AREA TO BE IMPACTED BY THE HEAVY RAIN. WE DO NOT EXPECT TO ACTIVATE SPOTTER NETWORKS...BUT ASK SPOTTERS TO REPORT ANY FLOODING PROBLEMS...AND IF RAIN GAUGES ARE AVAILABLE...ANY RAINFALL AMOUNTS IN EXCESS OF 1 INCH. RTG
Special weather statement, Jul 25, 11:40 AM MDT, 4 hours 49 minutes before
COZ030-032>050-260600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER COLORADO 1140 AM MDT SAT JUL 25 1998 ...CORRECTED DATE... THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES ADAMS ARAPAHOE BOULDER CLEAR CREEK DENVER DOUGLAS ELBERT GILPIN GRAND JACKSON JEFFERSON LARIMER LINCOLN LOGAN MORGAN PARK PHILLIPS SEDGWICK SUMMIT WASHINGTON WELD SYNOPSIS: VERY LITTLE HAS CHANGED IN 24 HOURS. A VERY MOIST AIRMASS RESIDES OVER EASTERN COLORADO WITH A VERY WEAK WIND PATTERN THROUGH THE ATMOSPHERE. THE RESULT WILL BE ANOTHER ROUND OF WIDESPREAD SLOW MOVING THUNDERSTORMS THIS AFTERNOON AND EVENING. THE MOST LIKELY FOCUS FOR THESE STORMS WILL BE A WIND CONVERGENCE BOUNDARY...WHICH WILL EXTEND FROM NORTHEAST WELD COUNTY TO EASTERN ELBERT COUNTY EARLY THIS AFTERNOON...AND SLIGHTLY FURTHER WEST BY EARLY EVENING. AS WE HAVE SEEN IN THE PAST FEW DAYS...OUTFLOW BOUNDARIES FROM THE STORMS WILL BE CRITICAL IN HOW STORMS DEVELOP AND MOVE THROUGH THE AFTERNOON AND EVENING. TORRENTIAL RAINFALL RATES ARE AGAIN POSSIBLE...IN THE HEART OF SOME STORMS RAINFALL RATES OF 2.5 INCHES AN HOUR ARE POSSIBLE...WITH 3 TO 4 INCHES POSSIBLE IN AN HOUR. WE WILL MOST LIKELY ISSUE ANOTHER FLASH FLOOD WATCH LATER THIS AFTERNOON...AS WE BETTER DEFINE THE AREA TO BE IMPACTED BY THE HEAVY RAIN. WE DO NOT EXPECT TO ACTIVATE SPOTTER NETWORKS...BUT ASK SPOTTERS TO REPORT ANY FLOODING PROBLEMS...AND IF RAIN GAUGES ARE AVAILABLE...ANY RAINFALL AMOUNTS IN EXCESS OF 1 INCH. RTG
Special weather statement, Jul 25, 4:09 PM MDT, 20 minutes before
COZ030-032>050-260600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER COLORADO 405PM MDT SAT JUL 25 1998 ...UPDATED... THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES ADAMS ARAPAHOE BOULDER CLEAR CREEK DENVER DOUGLAS ELBERT GILPIN GRAND JACKSON JEFFERSON LARIMER LINCOLN LOGAN MORGAN PARK PHILLIPS SEDGWICK SUMMIT WASHINGTON WELD ...FLASH FLOOD WATCH UNTIL MIDNIGHT... SYNOPSIS: ISSUED A FLASH FLOOD WATCH NORTHEAST COLORADO. THIS AREA HAS SEEN A LOT OF RAIN THE PAST FEW NIGHTS...AND ARE PRIMED FOR MORE SLOW MOVING THUNDERSTORMS THIS EVENING. FOR THE AREAS THAT HAD THE HIGHEST SOIL MOISTURE. WEST OF THE WATCH AREA...THERE WILL ALSO BE SLOW MOVING HEAVY RAIN STORMS. TORRENTIAL RAINFALL RATES ARE AGAIN POSSIBLE...IN THE HEART OF SOME STORMS RAINFALL RATES OF 2.5 INCHES AN HOUR ARE POSSIBLE...WITH 3 TO 4 INCHES POSSIBLE IN AN HOUR. PLEASE REPORT ANY FLOODING PROBLEMS...AND IF RAIN GAUGES ARE AVAILABLE...ANY RAINFALL AMOUNTS IN EXCESS OF 1 INCH. RTG
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 24, 8:28 PM MDT | Flash Flood Warning | BOU | Adams, Arapahoe | 3 hr |
| Jul 25, 2:44 PM MDT | Tornado Warning | BOU | Larimer, Weld | 26 min |
| Jul 25, 4:15 PM MDT | Severe Thunderstorm Warning | BOU | Logan | 30 min |
| Jul 25, 4:50 PM MDT | Flash Flood Warning | BOU | Clear Creek | 115 min |
| Jul 25, 5:03 PM MDT | Tornado Warning | BOU | Adams, Denver | 27 min |
| Jul 25, 5:07 PM MDT | Flash Flood Warning | BOU | Morgan | 3 hr |
| Jul 25, 5:35 PM MDT | Flash Flood Warning | BOU | Washington | 2 hr |
| Jul 25, 5:41 PM MDT | Flash Flood Warning | BOU | Washington | 2 hr |
Nearby
Flash Flood Warnings in Colorado, 1998Every flash flood warning in 1998
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.