Alert archive / Colorado / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 156, NWS Denver/Boulder, CO

August 11, 1998Logan County, Weld County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 11, 1998, 4:20 PM MDT for Logan County, Weld County, Colorado. It was in force for 40 min. 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 11, 1998, 4:20 PM MDT (22:20 UTC)
Expired
Aug 11, 1998, 5:00 PM MDT
In force
40 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

Counties Logan County, CO, Weld County, CO

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 10.3 hours before the alert went out and 96 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 1998-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 93 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 1998-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -24 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
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

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

What 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, 5 hours 5 minutes 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, 5 hours 5 minutes 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, 2 hours 7 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, 2 hours 7 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.

IssuedProductOfficeCountiesLasted
Aug 10, 6:15 PM MDTSevere Thunderstorm WarningBOUAdams, Weld45 min
Aug 10, 6:53 PM MDTSevere Thunderstorm WarningBOUWeld37 min
Aug 11, 3:15 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld55 min
Aug 11, 4:20 PM MDTSevere Thunderstorm WarningBOUAdams, Morgan, Weld60 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.