Alert archive / Colorado / Flash Flood Warnings in 1998

Flash Flood Warning 35, NWS Denver/Boulder, CO

August 21, 1998Arapahoe County, Elbert County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Aug 21, 1998, 7:15 PM MDT for Arapahoe County, Elbert 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
Aug 21, 1998, 7:15 PM MDT (01:15 UTC)
Expired
Aug 21, 1998, 9:30 PM MDT
In force
2 hr
Issued by
NWS Denver/Boulder, CO
Area
Whole counties

Counties Arapahoe County, CO, Elbert County, CO

The radar

The Denver radar (KFTG), 44 km from the middle of the area, began a volume at 01:19 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, 1.3 hours before the alert went out and 97 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 1998-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 157 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 00:00Z on 1998-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 30 square meters per square second.193958Sfc1 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
157 J/kg
Mixed-layer CIN
-46 J/kg
Mixed-layer LCL
2273 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
30 m²/s²
0-3 km storm-relative helicity
15 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDEN 220120
FFWDEN
COC005-039-220330-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
715 PM MDT FRI AUG 21 1998

THE NATIONAL WEATHER SERVICE IN DENVER HAS EXTENDED A 

* FLASH FLOOD WARNING FOR...
     NORTHWESTERN ELBERT COUNTY IN EAST CENTRAL COLORADO
     SOUTH CENTRAL ARAPAHOE COUNTY IN NORTHEAST COLORADO 

* UNTIL 930 PM MDT

* AT 710 PM MDT...THE ELBERT COUNTY SHERIFF REPORTED CONSIDERABLE 
  FLOODING ALONG COAL CREEK IN NORTHWEST ELBERT COUNTY.  LARGE 
  TREE TRUNKS AND BOATS WERE WASHING DOWNSTREAM.  

ONLY A FEW SPRINKLES REMAINED IN THE AREA...BUT HEAVY RAINFALL 
OF 5 TO 7 INCHES EARLIER IN THE EVENING WAS CAUSING THE FLOODING 
PROBLEMS.  PEOPLE ALONG COAL CREEK FROM NORTHWEST ELBERT COUNTY 
THROUGH SOUTH CENTRAL ARAPAHOE COUNTY SHOULD TAKE IMMEDIATE ACTION
TO PROTECT LIFE AND PROPERTY.  

MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS 
BRIDGES...DIPS...OR OTHER LOW SPbOTS 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.

BARJENBRUCH

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 21, 9:25 PM MDTFlash Flood WarningBOUArapahoe, Elbert95 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.