Alert archive / Colorado / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 154, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 11, 1998, 3:15 PM MDT for Morgan County, Weld County, Colorado. It was in force for 55 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
- Aug 11, 1998, 3:15 PM MDT (21:15 UTC)
- Expired
- Aug 11, 1998, 4:10 PM MDT
- In force
- 55 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
Counties Morgan County, CO, Weld County, CO
The nearest sounding before it
Denver, CO (KDNR), launched 12:00Z, 9.3 hours before the alert went out and 116 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
- 93 J/kg
- Mixed-layer CIN
- -174 J/kg
- Mixed-layer LCL
- 1415 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- -24 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.
896
WUUS1 KDEN 112121
SVRDEN
COC087-123-112210-
BULLETIN - IMMEDIATE BROADCAST REQUESTED ...CORRECTION...
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
315 PM MDT TUE AUG 11 1998
THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A
* SEVERE THUNDERSTORM WARNING FOR...
NORTHWESTERN MORGAN AND EASTERN WELD COUNTIES IN NORTHEAST
COLORADO
* UNTIL 410 PM MDT
* AT 312 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM 6 MILES NORTHEAST OF BRIGGSDALE...OR ABOUT 32
MILES NORTHEAST OF GREELEY...MOVING SOUTHEAST AT 15 MILES PER HOUR.
LOCATIONS WITHIN THE WARNING INCLUDE...BRIGGSDALE...BUCKINGHAM...
RAYMER...BARNSVILLE...KEOTA AND JACKSON RESERVOIR.
DOPPLER RADAR WAS INDICATING VERY HEAVY RAIN AND LARGE HAIL WITH
THIS STORM. RADAR ALSO DETECTED A WEAK CIRCULATION WITHIN THIS
STORM.
SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR NO ADVANCE
WARNING. PREPARE TO MOVE TO A PLACE OF SAFETY IN A STURDY STRUCTURE
SUCH AS A BASEMENT OR SMALL INTERIOR ROOM IF A TORNADO IS SPOTTED.
HEAVY RAINS FROM THIS STORM MAY FLOOD LOW LYING AREAS SUCH AS
DITCHES AND UNDERPASSES. AVOID THESE AREAS AND DO NOT CROSS FLOODED
ROADS AS THEY MAY BE WASHED OUT. WATER LEVELS OF SMALL STREAMS AND
RIVERS MAY ALSO RISE...THEREFORE SEEK HIGHER GROUND IF THREATENED BY
FLOOD WATERS.
BAKER
LAT...LON 4054 10454 4026 10421 4076 10360 4085 10424What forecasters said that day
The local office's own words before this severe thunderstorm 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 11, 11:15 AM MDT, 4 hours before
COZ030-032>050-120600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 1115 AM MDT TUE AUG 11 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 AIR DISTURBANCE WILL BE MOVING THROUGH THE EASTERN PLAINS THIS AFTERNOON. THIS IN ADDITION TO ABUNDANT MOISTURE AND VERY WEAK STEERING WINDS WILL ACT TO PRODUCE LOCALLY HEAVY RAINS AGAIN THIS AFTERNOON. BEST CHANCES FOR HEAVY RA IN ARE IN THE AREA FROM AKRON EASTWARD IN THE PLAINS AND HEAVY THUNDERSTORMS SHOULD NOT DEVELOP BEFORE MID AFTERNOON. SPOTTER ACTIVITATION MAY BE REQUIRED LATER. TUNNELL
Special weather statement, Aug 11, 11:15 AM MDT, 4 hours before
COZ030-032>050-120600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 1115 AM MDT TUE AUG 11 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 AIR DISTURBANCE WILL BE MOVING THROUGH THE EASTERN PLAINS THIS AFTERNOON. THIS IN ADDITION TO ABUNDANT MOISTURE AND VERY WEAK STEERING WINDS WILL ACT TO PRODUCE LOCALLY HEAVY RAINS AGAIN THIS AFTERNOON. BEST CHANCES FOR HEAVY RA IN ARE IN THE AREA FROM AKRON EASTWARD IN THE PLAINS AND HEAVY THUNDERSTORMS SHOULD NOT DEVELOP BEFORE MID AFTERNOON. SPOTTER ACTIVITATION MAY BE REQUIRED LATER. TUNNELL
Special weather statement, Aug 11, 2:13 PM MDT, 1 hour 2 minutes before
COZ030-033-035-038-039-042>044-048-112115- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 213 PM MDT TUE AUG 11 1998 ...LINE OF THUNDERSTORMS MOVING INTO NORTHERN LARIMER...NORTHERN WELD...AND WESTERN LOGAN COUNTIES OF COLORADO... AT 210 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THUNDERSTORMS ALONG A LINE EXTENDING FROM NEAR HEREFORD IN NORTHEAST WELD COUNTY TO 40 MILES NORTHWEST OF FORT COLLINS. THIS LINE OF STORMS WAS MOVING SOUTHEAST AT 20 MILES PER HOUR. PERSONS IN THE PATH OF THESE THUNDERSTORMS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER AND MOVE TO A PLACE OF SAFETY IF BAD WEATHER APPROACHES. DANGEROUS LIGHTNING...HAIL...HEAVY RAIN...AND STRONG GUSTY WINDS WILL OCCUR WITH THESE STORMS AS THEY MOVE SOUTHEAST ACROSS EASTERN LARIMER...CENTRAL AND NORTHEAST WELD AND WESTERN LOGAN COUNTIES BY 3 PM. BAKER
Special weather statement, Aug 11, 2:13 PM MDT, 1 hour 2 minutes before
COZ030-033-035-038-039-042>044-048-112115- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 213 PM MDT TUE AUG 11 1998 ...LINE OF THUNDERSTORMS MOVING INTO NORTHERN LARIMER...NORTHERN WELD...AND WESTERN LOGAN COUNTIES OF COLORADO... AT 210 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THUNDERSTORMS ALONG A LINE EXTENDING FROM NEAR HEREFORD IN NORTHEAST WELD COUNTY TO 40 MILES NORTHWEST OF FORT COLLINS. THIS LINE OF STORMS WAS MOVING SOUTHEAST AT 20 MILES PER HOUR. PERSONS IN THE PATH OF THESE THUNDERSTORMS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER AND MOVE TO A PLACE OF SAFETY IF BAD WEATHER APPROACHES. DANGEROUS LIGHTNING...HAIL...HEAVY RAIN...AND STRONG GUSTY WINDS WILL OCCUR WITH THESE STORMS AS THEY MOVE SOUTHEAST ACROSS EASTERN LARIMER...CENTRAL AND NORTHEAST WELD AND WESTERN LOGAN COUNTIES BY 3 PM. BAKER
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 10, 6:15 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Weld | 45 min |
| Aug 10, 6:53 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 37 min |
| Aug 11, 4:20 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Morgan, Weld | 60 min |
| Aug 11, 4:20 PM MDT | Severe Thunderstorm Warning | BOU | Logan, Weld | 40 min |
Nearby
Severe Thunderstorm Warnings in Colorado, 1998Every severe thunderstorm 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.