Alert archive / Colorado / Tornado Warnings in 1991
Tornado Warning 49, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this tornado warning at Jul 25, 1991, 4:39 PM MDT for Weld County, Colorado. It was in force for 36 min. 2 reports came from inside the area while it was in force.
The area
The counties it named, with what was reported inside it.
The facts
- Issued
- Jul 25, 1991, 4:39 PM MDT (22:39 UTC)
- Expired
- Jul 25, 1991, 5:15 PM MDT
- In force
- 36 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Whole counties
County Weld County, CO
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 25, 4:43 PM MDT | Tornado F0 | Weld, CO | |
| Jul 25, 5:02 PM MDT | Tornado F0 | Weld, 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. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.
The nearest sounding before it
Denver, CO (KDEN), launched 12:00Z, 10.7 hours before the alert went out and 125 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
- 10 J/kg
- Mixed-layer CIN
- -72 J/kg
- Mixed-layer LCL
- 820 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- 28 m²/s²
- 0-3 km storm-relative helicity
- 87 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000
TTAA00 KDEN 252242
TORDEN
COC123-252315-
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
439 PM MDT THU JUL 25 1991
THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A TORNADO
WARNING EFFECTIVE UNTIL 515 PM MDT FOR PEOPLE IN THE FOLLOWING
COUNTIES
IN NORTHEASTERN COLORADO
NORTHWESTERN WELD
INCLUDING THE FOLLOWING TOWNS/CITIES
NUNN...CARR AND ROCKPORT
AT 439 PM MDT THE PUBLIC REPORTED A TORNADO 7 MILES NORTHWEST OF NUNN
OR ABOUT 27 MILES NORTH OF GREELEY. NO MOVEMENT WAS REPORTED.
THE STORM PRODUCING THE TORNADO WAS SHOWING LITTLE MOVEMENT ON RADAR.
IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
SUBSTANTIAL SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN
THE NEAREST DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH
YOUR HANDS.
TO REPORT SEVERE WEATHER HAVE THE NEAREST LAW ENFORCEMENT
AGENCY RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
FORECAST OFFICE IN DENVER.
DULONG
LAT...LON 4075 10467 4074 10493 4091 10494 4091 10467What forecasters said that day
The local office's own words before this tornado 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, 12:04 PM MDT, 4 hours 35 minutes before
COZ011-242230- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 1205PM MDT THU JULY 2 1991 ...THUNDERSTORMS BUILDING ALONG FOOTHILLS WEST OF DENVER... AT NOON THUNDERSTORMS WERE BUILDING WEST OF DENVER IN BOULDER AND JEFFERSON COUNTIES AND MOVING TOWARD THE EAST AT AROUND 15 MILES AN HOUR. ALTHOUGH THESE STORMS ARE MOVING FAIRLY RAPIDLY SOME COULD CONTAIN HEAVY RAIN AND AMOUNTS OF AN INCH OR SO AN HOUR CAN BE EXPECTED FROM SOME STORMS. SMALL HAIL AND STRONG WINDS ARE ALSO A POSSIBLITY WITH THE STORMS. STORMS ARE FORECAST TO CONTINUE TO BUILD ALONG THE FOOTHILLS FOR THE NEXT SEVERAL HOURS AND MOVE EASTWARD INTO THE PLAINS. FURHER STATEMENTS OR ADVISORIES WILL BE ISSUED AS REQUIRED. LET
Special weather statement, Jul 25, 12:15 PM MDT, 4 hours 24 minutes before
COZ011-242230- SPECIAL WEATHER STATEMENT...CORRECTION ON TIME NATIONAL WEATHER SERVICE DENVER CO 1205PM MDT THU JULY 25 1991 ...THUNDERSTORMS BUILDING ALONG FOOTHILLS WEST OF DENVER... AT NOON THUNDERSTORMS WERE BUILDING WEST OF DENVER IN BOULDER AND JEFFERSON COUNTIES AND MOVING TOWARD THE EAST AT AROUND 15 MILES AN HOUR. ALTHOUGH THESE STORMS ARE MOVING FAIRLY RAPIDLY SOME COULD CONTAIN HEAVY RAIN AND AMOUNTS OF AN INCH OR SO AN HOUR CAN BE EXPECTED FROM SOME STORMS. SMALL HAIL AND STRONG WINDS ARE ALSO A POSSIBLITY WITH THE STORMS. STORMS ARE FORECAST TO CONTINUE TO BUILD ALONG THE FOOTHILLS FOR THE NEXT SEVERAL HOURS AND MOVE EASTWARD INTO THE PLAINS. FURHER STATEMENTS OR ADVISORIES WILL BE ISSUED AS REQUIRED. LET
Special weather statement, Jul 25, 12:44 PM MDT, 3 hours 55 minutes before
COZ011-241930- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 1240PM MDT THURSDAY JULY 25 1991 ...HEAVY RAIN AND HAIL IN SOUTHERN JEFFERSON COUNTY... AT 1240 PM MDT RADAR INDICATED A VERY STRONG THUNDERSTORM IN SOUTHERN JEFFERSON COUNTY JUST SOUTH OF BUFFALO CREEK OR ABOUT 30 MILES SOUTHWEST OF DENVER. A SPOTTER IN THE TOWN OF BUFFALO CREEK CONFIRMED THE THUNDERSTORM AND REPORTED PEA SIZE HAIL AND HEAVY RAIN. THE SPOTTER REPORTED THAT 3/4 INCH OF RAIN FELL IN 30 MINUTES. THIS THUNDERSTORM WAS MOVING TO THE SOUTHEAST AT 10 TO 15 MPH. THUNDERSTORMS WILL CONTINUE TO BUILD ALONG THE FOOTHILLS FOR THE NEXT SEVERAL HOURS BEFORE MOVING INTO THE PLAINS. STAY TUNED TO NOAA WEATHER RADIO OR LOCAL NEWS MEDIA FOR FUTURE FORECASTS AND BULLETINS. BE ALERT FOR THE POTENTIAL EXISTS FOR HEAVY RAIN AND HAIL CAUSING SMALL STREAMS AND CREEKS TO RUN QUITE HIGH. LOCALLY HEAVY RAIN OF AN INCH OR SO PER HOUR COULD CAUSE TRAVELLINBG PROBLEMS BY CAUSING WATER TO POND ON ROADS ESPECIALLY IN LOW LYING AREAS. HEAVY RAIN COULD ALSO CAUSE SOME ROCK AND MUD SLIDES IN STEEP TERRAIN IN THE MOUNTAINS AND FOOTHILLS. END...GCF...WSFO DENVER
Special weather statement, Jul 25, 3:08 PM MDT, 1 hour 31 minutes before
COZ011-242200- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 205 PM MDT THU JULY 25 1991 ...STRONG THUNDERSTORM OVER NORTHWEST METRO DENVER... AT 200 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER NORTHEAST JEFFERSON COUNTY NEAR ARVADA AND WESTMINSTER. THIS STORM WAS MOVING TO THE SOUTHEAST AT 10 TO 15 MPH. ALL PEOPLE IN THE NORTHERN HALF OF THE DENVER METRO AREA INCLUDING ARVADA...WESTMINSTER...THORNTON...NORTHGLENN...COMMERCE CITY AND NORTH DENVER SHOULD BE ALERT FOR FREQUENT DANGEROUS LIGHTNING...HAIL AND STRONG GUSTY WINDS FROM THIS STORM TIL 300 PM MDT THIS AFTERNOON. BRIEF HEAVY RAIN...UP TO AN INCH AN HOUR...WILL CAUSE LOCAL| FLOODING OF STREETS AND LOW LYING OR FLOOD PRONE AREAS. PONDING OF WATER ON STREETS COULD CAUSE TRAVEL PROBLEMS FOR MOTORISTS. GARD...WSFO DENVER
Special weather statement, Jul 25, 3:10 PM MDT, 1 hour 29 minutes before
COZ011-242200- SPECIAL WEATHER STATEMENT ...CORRECT TIMES... NATIONAL WEATHER SERVICE DENVER CO 305 PM MDT THU JULY 25 1991 ...STRONG THUNDERSTORM OVER NORTHWEST METRO DENVER... AT 300 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER NORTHEAST JEFFERSON COUNTY NEAR ARVADA AND WESTMINSTER. THIS STORM WAS MOVING TO THE SOUTHEAST AT 10 TO 15 MPH. ALL PEOPLE IN THE NORTHERN HALF OF THE DENVER METRO AREA INCLUDING ARVADA...WESTMINSTER...THORNTON...NORTHGLENN...COMMERCE CITY AND NORTH DENVER SHOULD BE ALERT FOR FREQUENT DANGEROUS LIGHTNING...HAIL AND STRONG GUSTY WINDS FROM THIS STORM TIL 400 PM MDT THIS AFTERNOON. BRIEF HEAVY RAIN...UP TO AN INCH AN HOUR...WILL CAUSE LOCAL FLOODING OF STREETS AND LOW LYING OR FLOOD PRONE AREAS. PONDING OF WATER ON STREETS COULD CAUSE TRAVEL PROBLEMS FOR MOTORISTS. GARD...WSFO DENVER
Special weather statement, Jul 25, 4:17 PM MDT, 22 minutes before
COZ011-242330- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 415 PM MDT THU JULY 25 1991 ...SEVERE THUNDERSTORM WARNING EXPIRES FOR EASTCENTRAL DENVER AND SOUTHWESTERN ADAMS COUNTIES... AT 415 PM MDT RADAR AND SPOTTER REPORTS WERE STILL INDICATING A VERY STRONG THUNDERSTORM MAINLY OVER NORTHEAST AURORA...NORTH OF I-70. THERE HAVE BEEN NO REPORTS OF SEVERE WEATHER...THOUGH RADAR INDICATES STORM TOTALS OF AT LEAST TWO INCHES OF RAIN SINCE ABOUT 300 PM. LISTEN FOR THE LATEST URBAN AND SMALL STREAM FLOOD ADVISORIES FOR FURTHER INFORMATION ON THIS STORM. MCQUEEN
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 25, 3:28 PM MDT | Tornado Warning | BOU | Adams, Weld | 32 min |
| Jul 25, 3:48 PM MDT | Tornado Warning | BOU | Adams, Weld | 27 min |
| Jul 25, 3:49 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Denver | 26 min |
| Jul 25, 4:09 PM MDT | Tornado Warning | BOU | Boulder, Weld | 36 min |
| Jul 25, 4:09 PM MDT | Tornado Warning | BOU | Adams | 36 min |
Nearby
Tornado Warnings in Colorado, 1991Every tornado warning in 1991Tornadoes in 1991
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.