Alert archive / Colorado / Flash Flood Warnings in 1998

Flash Flood Warning 10, NWS Denver/Boulder, CO

July 25, 1998Morgan County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 25, 1998, 5:07 PM MDT for Morgan 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, 5:07 PM MDT (23:07 UTC)
Expired
Jul 25, 1998, 8:00 PM MDT
In force
3 hr
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Morgan County, CO

The radar

The Denver radar (KFTG), 99 km from the middle of the area, began a volume at 23:14 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 84 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 1998-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 114 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 1998-07-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -29 square meters per square second.1939Sfc1 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
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

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDEN 252314 COR
FFWDEN
COC087-250200-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING...CORRECTED
NATIONAL WEATHER SERVICE DENVER CO
507 PM MDT SAT JUL 25 1998

...CORRECTED HEADER...

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* FLASH FLOOD WARNING FOR...
     NORTH CENTRAL MORGAN COUNTY IN NORTHEAST COLORADO

* UNTIL 800 PM MDT

* AT 503 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN 3 MILES NORTH OF ANTELOPE SPRINGS...OR ABOUT 17 
  MILES NORTH OF FORT MORGAN...MOVING SOUTHEAST A 10 MILES PER HOUR.

LOCATIONS IN THE WARNING INCLUDE...ANTELOPE SPRINGS

RADAR ESTIMATES THAT 3 TO 4 INCHES OF RAIN HAVE ALREADY FALLEN 
FROM 3 MILES NORTH OF ANTELOPE SPRINGS TO 8 MILES NORTHWEST OF
ANTELOPE SPRINGS.  ANOTHER INTENSE STORM WILL DROP ANOTHER 1 TO
2 INCHES OF RAIN BETWEEN 515 AND 615 PM.  THIS WILL ADD TO THE 
FLOODING PROBLEMS.

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...NORMALLY DRY WASHES AND
ARROYOS...AS WELL AS FARMLAND ALONG THE BANKS OF CREEKS AND STREAMS.

LAT...LON 4051 10394 4045 10387 4041 10365 4052 10367

BARJENBRUCH

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 29 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 27 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 27 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, 58 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.

IssuedProductOfficeCountiesLasted
Jul 24, 8:28 PM MDTFlash Flood WarningBOUAdams, Arapahoe3 hr
Jul 25, 2:44 PM MDTTornado WarningBOULarimer, Weld26 min
Jul 25, 4:15 PM MDTSevere Thunderstorm WarningBOULogan30 min
Jul 25, 4:29 PM MDTFlash Flood WarningBOULogan3 hr
Jul 25, 4:50 PM MDTFlash Flood WarningBOUClear Creek115 min
Jul 25, 5:03 PM MDTTornado WarningBOUAdams, Denver27 min
Jul 25, 5:35 PM MDTFlash Flood WarningBOUWashington2 hr
Jul 25, 5:41 PM MDTFlash Flood WarningBOUWashington2 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.