Alert archive / Colorado / Flash Flood Warnings in 1998
Flash Flood Warning 11, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at Jul 25, 1998, 5:35 PM MDT for Washington County, Colorado. 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
- Jul 25, 1998, 5:35 PM MDT (23:35 UTC)
- Expired
- Jul 25, 1998, 8:00 PM MDT
- In force
- 2 hr
- Issued by
- NWS Denver/Boulder, CO
- Area
- Whole counties
County Washington County, CO
The radar
The Denver radar (KFTG), 117 km from the middle of the area, began a volume at 23:38 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, 11.6 hours before the alert went out and 11 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
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.
In the hours before
Special weather statement, Jul 25, 11:38 AM MDT, 5 hours 57 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, 5 hours 55 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, 5 hours 55 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, 1 hour 26 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, 4:29 PM MDT | Flash Flood Warning | BOU | Logan | 3 hr |
| 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, 5:41 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.