Alert archive / Colorado / Flash Flood Warnings in 1998
Flash Flood Warning 34, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at Aug 21, 1998, 4:19 PM MDT for Arapahoe County, Douglas County, Elbert 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
- Aug 21, 1998, 4:19 PM MDT (22:19 UTC)
- Expired
- Aug 21, 1998, 7:15 PM MDT
- In force
- 3 hr
- Issued by
- NWS Denver/Boulder, CO
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
Counties Arapahoe County, CO, Douglas County, CO, Elbert County, CO
The radar
The Denver radar (KFTG), 28 km from the middle of the area, began a volume at 22:21 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, 10.3 hours before the alert went out and 124 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2002 m above ground
- 0-6 km bulk shear
- 4 kt
- 0-1 km storm-relative helicity
- 21 m²/s²
- 0-3 km storm-relative helicity
- -22 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 212221
FFWDEN
COC005-035-039-220115-
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
419 PM MDT FRI AUG 21 1998
THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A
* FLASH FLOOD WARNING FOR...
NORTHWESTERN ELBERT COUNTY IN EAST CENTRAL COLORADO
SOUTH CENTRAL ARAPAHOE COUNTY IN NORTHEAST COLORADO
EXTREME NORTHEASTERN DOUGLAS COUNTY IN NORTHEAST COLORADO
* UNTIL 715 PM MDT
* AT 415 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
VERY HEAVY RAIN FROM 6 MILES EAST OF PARKER IN EXTREME NORTHEAST
DOUGLAS COUNTY TO 10 MILES SOUTH OF BENNETT IN SOUTH CENTRAL
ARAPAHOE COUNTY. THE STORMS WERE MOVING VERY SLOWLY NORTHEAST
AT 10 MILES PER HOUR.
RADAR INDICATED BETWEEN 3 AND 4 INCHES OF RAIN HAS ALREADY FALLEN
IN THE WARNING AREA. THESE STORMS SHOULD SLOWLY DIMINISH BY 515
PM...BUT ADDITIONAL RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE POSSIBLE.
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. T
O ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.
LAT...LON 3954 10469 3946 10468 3949 10456 3961 10445
3958 10463What 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, Aug 21, 10:45 AM MDT, 5 hours 34 minutes before
COZ030-032>050-220600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 1045 AM MDT FRI AUG 21 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...AN UPPER RIDGE OF HIGH PRESSURE OVER THE GREAT PLAINS WILL CONTINUE TO ALLOW TROPICAL MONSOONAL MOISTURE TO STREAM ACROSS COLORADO THIS AFTERNOON AND TONIGHT. AN UPPER LEVEL DISTURBANCE EMBEDDED IN THE MOIST FLOW WILL MOVE ACROSS THE AREA TONIGHT. THIS WILL ENHANCE THE FORMATION OF CONVECTIVE STORMS WELL INTO THE NIGHT. SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN MOVE OFF THE MOUNTAINS AND EASTERN FOOTHILLS THIS AFTERNOON AND SPREAD OVER THE EASTERN PLAINS LATE THIS AFTERNOON AND TONIGHT. DUE TO RELATIVELY LIGHT WINDS ALOFT AND HIGH PRECIPITIBLE WATERS THE STORMS WILL LIKELY PRODUCE LOCALLY HEAVY RAINFALL. MAXIMUM POSSIBLE THUNDERSTORM RAINFALL MAY TOTAL BETWEEN 2 AND 3 INCHES. THIS AMOUNT OF RAIN MAY CAUSE SMALL STREAM FLOODING AND URBAN STREET FLOODING. A HIGH FREEZING LEVEL SHOULD KEEP HAIL SIZE SMALL. MOST STORMS WILL NOT BE SEVERE BUT ONE OR TWO MAY PRODUCE STRONG GUSTY WINDS ABOVE SEVERE THUNDERSTORM WIND CRITERIA OF 58 MPH. SPOTTER ACTIVATION WILL NOT BE REQUIRED...BUT SIGNIFICANT RAINFALL OR FLOODING REPORTS WOULD BE GREATLY APPRECIATED. GARD...WSFO DENVER
Special weather statement, Aug 21, 10:45 AM MDT, 5 hours 34 minutes before
COZ030-032>050-220600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 1045 AM MDT FRI AUG 21 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...AN UPPER RIDGE OF HIGH PRESSURE OVER THE GREAT PLAINS WILL CONTINUE TO ALLOW TROPICAL MONSOONAL MOISTURE TO STREAM ACROSS COLORADO THIS AFTERNOON AND TONIGHT. AN UPPER LEVEL DISTURBANCE EMBEDDED IN THE MOIST FLOW WILL MOVE ACROSS THE AREA TONIGHT. THIS WILL ENHANCE THE FORMATION OF CONVECTIVE STORMS WELL INTO THE NIGHT. SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN MOVE OFF THE MOUNTAINS AND EASTERN FOOTHILLS THIS AFTERNOON AND SPREAD OVER THE EASTERN PLAINS LATE THIS AFTERNOON AND TONIGHT. DUE TO RELATIVELY LIGHT WINDS ALOFT AND HIGH PRECIPITIBLE WATERS THE STORMS WILL LIKELY PRODUCE LOCALLY HEAVY RAINFALL. MAXIMUM POSSIBLE THUNDERSTORM RAINFALL MAY TOTAL BETWEEN 2 AND 3 INCHES. THIS AMOUNT OF RAIN MAY CAUSE SMALL STREAM FLOODING AND URBAN STREET FLOODING. A HIGH FREEZING LEVEL SHOULD KEEP HAIL SIZE SMALL. MOST STORMS WILL NOT BE SEVERE BUT ONE OR TWO MAY PRODUCE STRONG GUSTY WINDS ABOVE SEVERE THUNDERSTORM WIND CRITERIA OF 58 MPH. SPOTTER ACTIVATION WILL NOT BE REQUIRED...BUT SIGNIFICANT RAINFALL OR FLOODING REPORTS WOULD BE GREATLY APPRECIATED. GARD...WSFO DENVER
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 3:17 PM MDT | Severe Thunderstorm Warning | BOU | Douglas, Elbert | 43 min |
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.