Alert archive / Colorado / Flash Flood Warnings in 1998

Flash Flood Warning 22, NWS Denver/Boulder, CO

July 31, 1998Jefferson County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 31, 1998, 5:05 PM MDT for Jefferson County, Colorado. It was in force for 85 min. 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 31, 1998, 5:05 PM MDT (23:05 UTC)
Expired
Jul 31, 1998, 6:30 PM MDT
In force
85 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Jefferson County, CO

The radar

The Denver radar (KFTG), 74 km from the middle of the area, began a volume at 23:07 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, 11.1 hours before the alert went out and 179 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 12:00Z on 1998-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 54 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 12:00Z on 1998-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 47 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
54 J/kg
Mixed-layer CIN
-239 J/kg
Mixed-layer LCL
728 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
47 m²/s²
0-3 km storm-relative helicity
105 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 312308
FFWDEN
COC059-010030-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
505 PM MDT FRI JUL 31 1998

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* FLASH FLOOD WARNING FOR...
     SOUTHERN JEFFERSON COUNTY IN NORTHEAST COLORADO

* UNTIL 630 PM MDT

* AT 456 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  VERY HEAVY RAIN NEAR BUFFALO CREEK WITH UP TO 2 INCHES OCCURRING   
  IN THE PAST 45 MINUTES..

LOCATIONS IN THE WARNING INCLUDE...BUFFALO CREEK...PINE AND SOUTH 
PLATTE

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 3947 10510 3924 10523 3925 10535 3947 10535

KLEYLA

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 31, 4:29 PM MDT, 36 minutes before
COZ036-312300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
429 PM MDT FRI JUL 31 1998

...THUNDERSTORMS DEVELOPING RAPIDLY NEAR BUFFALO CREEK IN SOUTHERN
JEFFERSON COUNTY...

AT 423 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR SHOWED RAPIDLY
DEVELOPING THUNDERSTORMS 3 MILES SOUTHWEST OF BUFFALO CREEK.  THESE
STORMS MAY PRODUCE UP TO 1 1/2 INCHES OF RAIN IN 45 MINUTES AS THEY
PASS OVER THE BUFFALO CREEK AREA.

THOSE LIVING IN AND NEAR BUFFALO CREEK SHOULD BE PREPARED FOR
RAPIDLY RISING WATER ALONG BUFFALO CREEK AS THE STORMS MOVE ACROSS
THE REGION IN THE NEXT 45 MINUTES.

KLEYLA
Special weather statement, Jul 31, 4:29 PM MDT, 36 minutes before
COZ036-312300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
429 PM MDT FRI JUL 31 1998

...THUNDERSTORMS DEVELOPING RAPIDLY NEAR BUFFALO CREEK IN SOUTHERN
JEFFERSON COUNTY...

AT 423 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR SHOWED RAPIDLY
DEVELOPING THUNDERSTORMS 3 MILES SOUTHWEST OF BUFFALO CREEK.  THESE
STORMS MAY PRODUCE UP TO 1 1/2 INCHES OF RAIN IN 45 MINUTES AS THEY
PASS OVER THE BUFFALO CREEK AREA.

THOSE LIVING IN AND NEAR BUFFALO CREEK SHOULD BE PREPARED FOR
RAPIDLY RISING WATER ALONG BUFFALO CREEK AS THE STORMS MOVE ACROSS
THE REGION IN THE NEXT 45 MINUTES.

KLEYLA

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 6:00 PM MDTFlash Flood WarningBOULincoln45 min
Jul 30, 6:00 PM MDTSevere Thunderstorm WarningBOULincoln45 min
Jul 30, 7:27 PM MDTFlash Flood WarningBOULincoln93 min
Jul 30, 8:56 PM MDTFlash Flood WarningBOULincoln2 hr
Jul 31, 3:15 PM MDTFlash Flood WarningBOUClear Creek, Gilpin, Jefferson60 min
Jul 31, 3:15 PM MDTSevere Thunderstorm WarningBOUClear Creek, Gilpin, Jefferson60 min
Jul 31, 5:50 PM MDTFlash Flood WarningBOUDouglas85 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.