Alert archive / Colorado / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 26, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at May 21, 1998, 5:35 PM MDT for Logan County, Colorado. It was in force for 35 min. 1 report came from 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, with what was reported inside it.
The facts
- Issued
- May 21, 1998, 5:35 PM MDT (23:35 UTC)
- Expired
- May 21, 1998, 6:10 PM MDT
- In force
- 35 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
County Logan County, CO
The radar
The Cheyenne radar (KCYS), 135 km from the middle of the area, began a volume at 23:39 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 21, 6:05 PM MDT | Hail 1 | Peetz, CO |
NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| May 21, 2:15 PM MDT | Tornado Watch | SPC | 6 hr |
The nearest sounding before it
Denver, CO (KDNR), launched 12:00Z, 11.6 hours before the alert went out and 117 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2454 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- 56 m²/s²
- 0-3 km storm-relative helicity
- 158 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
692
WUUS1 KDEN 212333 RRA
SVRDEN
COC075-220010-
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
535 PM MDT THU MAY 21 1998
THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A
* SEVERE THUNDERSTORM WARNING FOR...
NORTHERN LOGAN COUNTY IN NORTHEAST COLORADO
* UNTIL 610 PM MDT
* AT 526 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM 14 MILES WEST OF PEETZ...OR ABOUT 19 MILES
NORTH OF STERLING...MOVING EAST AT 25 MILES PER HOUR.
* LOCATIONS IN THE WARNING INCLUDE...PEETZ AND PROCTOR
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.
A TORNADO WATCH REMAINS IN EFFECT UNTIL 800 PM MDT FOR NORTHEAST
COLORADO.
THIS WARNING REPLACES THE SEVERE THUNDERSTORM WARNING ISSUED AT
451 PM MDT.
LAT...LON 4100 10344 4080 10342 4080 10291 4099 10294
LESZCYNSKIWhat 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, May 21, 11:53 AM MDT, 5 hours 42 minutes before
COZ030-032>050-220600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER COLORADO 1153 AM MDT THU MAY 21 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 SYSTEM PUSHED EAST OF THE AREA EARLIER THIS MORNING...BRINGING MORE STABLE AND DRY CONDITIONS...AS WELL AS DOWNSLOPE WINDS...TO PLAINS ADJACENT TO THE FOOTHILLS. HOWEVER...AT THE SURFACE AN AREA OF LOW PRESSURE WAS OVER SOUTHWEST WASHINGTON COUNTY AT THIS TIME...AND IS EXPECTED TO MOVE LITTLE THROUGH THE AFTERNOON. THE ASSOCIATED WIND FIELD WILL KEEP AREAS EAST AND NORTH OF THE LOW IN MORE MOIST UPSLOPE FLOW...AREAS TO THE SOUTH AND WEST WILL BE MUCH DRIER. SO THE SHOWERS AND THUNDERSTORMS THAT DEVELOP OVER THE ALPINE AREAS BY EARLY AFTERNOON WILL DISSIPATED WHEN THEY PUSH OFF THE FOOTHILLS INTO THESE DRY AREAS. EXPECT ONLY ISOLATED THUNDERSTORMS AFTER 4 PM IN JEFFERSON...DENVER...DOUGLAS...ELBERT... LINCOLN...ARAPAHOE COUNTIES. THE UPPER SYSTEM THAT PUSHED THROUGH EARLIER HAS LEFT A FAIRLY STABLE AREA AT THE MID LEVELS OF THE ATMOSPHERE. THIS WILL MAKE THUNDERSTORMS DEVELOPMENT MORE DIFFICULT...EVEN IN THE MORE MOIST COUNTIES. EXPECTED WIDELY SCATTERED SHOWERS AND THUNDERSTORMS AFTER 2:30 PM IN BOULDER...LARIMER...WELD...MORGAN...ADAMS...WASHINGTON ...LOGAN...PHILLIPS...AND SEDGWICK COUNTIES. SPOTTER ACTIVATION MAY BE NEEDED AFTER 3 PM OVER THE FAR NORTHEAST BORDER COUNTIES OF COLORADO. RJK
Special weather statement, May 21, 12:25 PM MDT, 5 hours 10 minutes before
COZ030-032>050-220600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER COLORADO 1153 AM MDT THU MAY 21 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 SYSTEM PUSHED EAST OF THE AREA EARLIER THIS MORNING...BRINGING MORE STABLE AND DRY CONDITIONS...AS WELL AS DOWNSLOPE WINDS...TO PLAINS ADJACENT TO THE FOOTHILLS. HOWEVER...AT THE SURFACE AN AREA OF LOW PRESSURE WAS OVER SOUTHWEST WASHINGTON COUNTY AT THIS TIME...AND IS EXPECTED TO MOVE LITTLE THROUGH THE AFTERNOON. THE ASSOCIATED WIND FIELD WILL KEEP AREAS EAST AND NORTH OF THE LOW IN MORE MOIST UPSLOPE FLOW...AREAS TO THE SOUTH AND WEST WILL BE MUCH DRIER. SO THE SHOWERS AND THUNDERSTORMS THAT DEVELOP OVER THE ALPINE AREAS BY EARLY AFTERNOON WILL DISSIPATED WHEN THEY PUSH OFF THE FOOTHILLS INTO THESE DRY AREAS. EXPECT ONLY ISOLATED THUNDERSTORMS AFTER 4 PM IN JEFFERSON...DENVER...DOUGLAS...ELBERT... LINCOLN...ARAPAHOE COUNTIES. THE UPPER SYSTEM THAT PUSHED THROUGH EARLIER HAS LEFT A FAIRLY STABLE AREA AT THE MID LEVELS OF THE ATMOSPHERE. THIS WILL MAKE THUNDERSTORMS DEVELOPMENT MORE DIFFICULT...EVEN IN THE MORE MOIST COUNTIES. EXPECTED WIDELY SCATTERED SHOWERS AND THUNDERSTORMS AFTER 2:30 PM IN BOULDER...LARIMER...WELD...MORGAN...ADAMS...WASHINGTON ...LOGAN...PHILLIPS...AND SEDGWICK COUNTIES. SPOTTER ACTIVATION MAY BE NEEDED AFTER 3 PM OVER THE FAR NORTHEAST BORDER C"OUNTIES OF COLORADO. RJK
Special weather statement, May 21, 4:16 PM MDT, 1 hour 19 minutes before
COZ043-044-212245- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 416 PM MDT THU MAY 21 1998 ...THUNDERSTORM IN FAR EAST CENTRAL WELD AND WEST CENTRAL MORGAN COUNTIES OF COLORADO AT 409 PM MDT THE PUBLIC REPORTED A POSSIBLE TORNADO BETWEEN FORT MORGAN AND WIGGINS. WEATHER SERVICE DOPPLER RADAR INDICATED A THUNDERSTORM ABOUT 3 MILES SOUTH OF ORCHARD...OR ABOUT 16 MILES WEST OF FORT MORGAN...MOVING NORTHEAST AT 30 MILES PER HOUR. THIS STORM LIES ALONG A BOUNDARY WHICH MAY PRODUCE A BRIEF FUNNEL CLOUD OR LANDSPOUT. PERSONS IN OR NEAR GOODRICH...JACKSON RESERVOIR...ORCHARD...WELDONA AND WIGGINS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER AND MOVE TO A PLACE OF SAFETY IF BAD WEATHER APPROACHES. ENTREKIN
Special weather statement, May 21, 4:16 PM MDT, 1 hour 19 minutes before
COZ043-044-212245- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 416 PM MDT THU MAY 21 1998 ...THUNDERSTORM IN FAR EAST CENTRAL WELD AND WEST CENTRAL MORGAN COUNTIES OF COLORADO AT 409 PM MDT THE PUBLIC REPORTED A POSSIBLE TORNADO BETWEEN FORT MORGAN AND WIGGINS. WEATHER SERVICE DOPPLER RADAR INDICATED A THUNDERSTORM ABOUT 3 MILES SOUTH OF ORCHARD...OR ABOUT 16 MILES WEST OF FORT MORGAN...MOVING NORTHEAST AT 30 MILES PER HOUR. THIS STORM LIES ALONG A BOUNDARY WHICH MAY PRODUCE A BRIEF FUNNEL CLOUD OR LANDSPOUT. PERSONS IN OR NEAR GOODRICH...JACKSON RESERVOIR...ORCHARD...WELDONA AND WIGGINS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER AND MOVE TO A PLACE OF SAFETY IF BAD WEATHER APPROACHES. ENTREKIN
Local storm report, May 21, 5:30 PM MDT, 5 minutes before
LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
530 PM MDT THU MAY 21 1998
...PRELIMINARY STORM REPORT FOR MAY 21 1998...
TIME(MDT) .....CITY LOCATION.....STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0430 PM 18 N NEW RAYMER CO 0.75 INCH HAIL
05/21/98 WELD
0430 PM 11 NE PAWNEE BUTTES CO 0.75 INCH HAIL
05/21/98 WELD
0435 PM 15 NE PAWNEE BUTTES CO 1.00 INCH HAIL
05/21/98 WELD
0445 PM 18 NE PAWNEE BUTTES CO 0.75 INCH HAIL
05/21/98 WELD
RAYLocal storm report, May 21, 5:30 PM MDT, 5 minutes before
LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
530 PM MDT THU MAY 21 1998
...PRELIMINARY STORM REPORT FOR MAY 21 1998...
TIME(MDT) .....CITY LOCATION.....STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0430 PM 18 N NEW RAYMER CO 0.75 INCH HAIL
05/21/98 WELD
0430 PM 11 NE PAWNEE BUTTES CO 0.75 INCH HAIL
05/21/98 WELD
0435 PM 15 NE PAWNEE BUTTES CO 1.00 INCH HAIL
05/21/98 WELD
0445 PM 18 NE PAWNEE BUTTES CO 0.75 INCH HAIL
05/21/98 WELD
RAYThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 20, 6:22 PM MDT | Severe Thunderstorm Warning | BOU | Washington | 38 min |
| May 20, 6:36 PM MDT | Severe Thunderstorm Warning | BOU | Washington | 24 min |
| May 20, 7:01 PM MDT | Severe Thunderstorm Warning | BOU | Washington | 39 min |
| May 21, 1:50 PM MDT | Severe Thunderstorm Warning | BOU | Logan | 55 min |
| May 21, 2:19 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 36 min |
| May 21, 3:18 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 42 min |
| May 21, 3:57 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 48 min |
| May 21, 4:22 PM MDT | Tornado Warning | BOU | Weld | 28 min |
| May 21, 4:51 PM MDT | Severe Thunderstorm Warning | BOU | Logan, Weld | 39 min |
| May 21, 5:41 PM MDT | Tornado Warning | BOU | Phillips, Sedgwick | 39 min |
| May 21, 5:47 PM MDT | Tornado Warning | BOU | Phillips, Sedgwick | 33 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.