Alert archive / Colorado / Tornado Warnings in 1998
Tornado Warning 20, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this tornado warning at Jul 23, 1998, 4:08 PM MDT for Adams County, Arapahoe County, Colorado. It was in force for 37 min. 1 report 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 23, 1998, 4:08 PM MDT (22:08 UTC)
- Expired
- Jul 23, 1998, 4:45 PM MDT
- In force
- 37 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Whole counties
Counties Adams County, CO, Arapahoe County, CO
The radar
The Denver radar (KFTG), 18 km from the middle of the area, began a volume at 22:11 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 |
|---|---|---|---|
| Jul 23, 4:15 PM MDT | Tornado F0 | Deer Trail, CO | Two small landspouts touched down briefly but did no damage. |
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 nearest sounding before it
Denver, CO (KDNR), launched 12:00Z, 10.1 hours before the alert went out and 95 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
- 81 J/kg
- Mixed-layer CIN
- -228 J/kg
- Mixed-layer LCL
- 1157 m above ground
- 0-6 km bulk shear
- 11 kt
- 0-1 km storm-relative helicity
- 76 m²/s²
- 0-3 km storm-relative helicity
- 85 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 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 23, 12:08 PM MDT, 4 hours before
COZ030-032>050-240600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 1208 PM MDT THU JUL 23 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 ...FLASH FLOOD WATCH UNTIL MIDNIGHT TONIGHT FOR SOUTHEAST ELBERT AND LINCOLN COUNTIES... SYNOPSIS: THE ATMOSPHERE REMAINS QUITE MOIST AS INDICATED BY HIGHER HUMIDITIES AND THE WIDESPREAD CLOUD COVER. CHANCES FOR RAINFALL LOOK GOOD THIS AFTERNOON AND EVENING ACROSS THE OUTLOOK AREA. HOWEVER A NUMBER OF FACTORS POINT TO NOT AS HEAVY OR AS WIDESPREAD RAINFALL TODAY. FIRST IS A LACK OF FAVORABLE EAST-NORTHEASTERLY UPSLOPE FLOW. SECOND IS THE LACK OF STRONG HEATING DUE TO THE HEAVY CLOUD COVER. AND THIRD IS THE LACK OF AN UPPER LEVEL WEATHER DISTURBANCE OR COLD FRONT TO FOCUS THUNDERSTORM ACTIVITY SUCH WAS THE CASE YESTERDAY. INITIAL SHOWER ACTIVITY EARLY THIS AFTERNOON WILL BE LIGHT AND SCATTERED IN COVERAGE. RAINFALL AMOUNTS WITH THESE SHOWERS WILL BE LESS THAN A QUARTER INCH. BY LATE THIS AFTERNOON THUNDERSTORMS FORMING OVER THE MOUNTAINS ARE EXPECTED TO MOVE SLOWLY NORTHEAST ONTO THE PLAINS. THUNDERSTORMS WILL BE SLOW MOVERS...AGAIN WITH SOME STORMS CAPABLE OF HEAVY RAIN. RAINFALL RATES FROM STORMS MOVING ACROSS THE FRONT RANGE URBAN CORRIDOR SHOULD RANGE FROM A TENTH TO ONE-HALF INCH...WITH SPOTTY RAINFALL RATES UP TO 1.5 INCHES. HEAVIEST RAINFALL SHOULD FALL ACROSS DOUGLAS...SOUTHERN JEFFERSON...ARAPAHOE AND SOUTHERN ELBERT AND SOUTHERN LINCOLN COUNTIES. SOILS IN THESE AREAS ARE ALREADY VERY WET FROM EARLIER RAINFALL. THUS LOCAL FLOODING OF LOW LYING AREAS AND SMALL STREAMS IS POSSIBLE IN THESE COUNTIES AFTER 4 PM MDT. SKYWARN STORM SPOTTERS ARE ASK TO RELAY ANY HEAVY RAIN OR FLOODING REPORTS TO THE NATIONAL WEATHER SERVICE IN DENVER. BAKER
Special weather statement, Jul 23, 12:08 PM MDT, 4 hours before
COZ030-032>050-240600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 1208 PM MDT THU JUL 23 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 ...FLASH FLOOD WATCH UNTIL MIDNIGHT TONIGHT FOR SOUTHEAST ELBERT AND LINCOLN COUNTIES... SYNOPSIS: THE ATMOSPHERE REMAINS QUITE MOIST AS INDICATED BY HIGHER HUMIDITIES AND THE WIDESPREAD CLOUD COVER. CHANCES FOR RAINFALL LOOK GOOD THIS AFTERNOON AND EVENING ACROSS THE OUTLOOK AREA. HOWEVER A NUMBER OF FACTORS POINT TO NOT AS HEAVY OR AS WIDESPREAD RAINFALL TODAY. FIRST IS A LACK OF FAVORABLE EAST-NORTHEASTERLY UPSLOPE FLOW. SECOND IS THE LACK OF STRONG HEATING DUE TO THE HEAVY CLOUD COVER. AND THIRD IS THE LACK OF AN UPPER LEVEL WEATHER DISTURBANCE OR COLD FRONT TO FOCUS THUNDERSTORM ACTIVITY SUCH WAS THE CASE YESTERDAY. INITIAL SHOWER ACTIVITY EARLY THIS AFTERNOON WILL BE LIGHT AND SCATTERED IN COVERAGE. RAINFALL AMOUNTS WITH THESE SHOWERS WILL BE LESS THAN A QUARTER INCH. BY LATE THIS AFTERNOON THUNDERSTORMS FORMING OVER THE MOUNTAINS ARE EXPECTED TO MOVE SLOWLY NORTHEAST ONTO THE PLAINS. THUNDERSTORMS WILL BE SLOW MOVERS...AGAIN WITH SOME STORMS CAPABLE OF HEAVY RAIN. RAINFALL RATES FROM STORMS MOVING ACROSS THE FRONT RANGE URBAN CORRIDOR SHOULD RANGE FROM A TENTH TO ONE-HALF INCH...WITH SPOTTY RAINFALL RATES UP TO 1.5 INCHES. HEAVIEST RAINFALL SHOULD FALL ACROSS DOUGLAS...SOUTHERN JEFFERSON...ARAPAHOE AND SOUTHERN ELBERT AND SOUTHERN LINCOLN COUNTIES. SOILS IN THESE AREAS ARE ALREADY VERY WET FROM EARLIER RAINFALL. THUS LOCAL FLOODING OF LOW LYING AREAS AND SMALL STREAMS IS POSSIBLE IN THESE COUNTIES AFTER 4 PM MDT. SKYWARN STORM SPOTTERS ARE ASK TO RELAY ANY HEAVY RAIN OR FLOODING REPORTS TO THE NATIONAL WEATHER SERVICE IN DENVER. BAKER
Special weather statement, Jul 23, 2:57 PM MDT, 1 hour 11 minutes before
COZ067-232130- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 257 PM MDT THU JUL 23 1998 ...THUNDERSTORMS INCREASING OVER SOUTHWESTERN DOUGLAS COUNTY... AT 250 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A THUNDERSTORM OVER WESTCREEK...OR ABOUT 27 MILES NORTHWEST OF COLORADO SPRINGS...MOVING EAST AT 10 MILES PER HOUR. THIS STORM WILL PRODUCE VERY HEAVY RAIN UP TO 2 INCHES PER HOUR ALONG WITH DANGEROUS LIGHTNING. PERSONS IN OR NEAR DEVIL'S HEAD...PERRY PARK AND WESTCREEK SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER AND MOVE TO A PLACE OF SAFETY IF BAD WEATHER APPROACHES. HEAVY RAINS MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES. AVOID T4HESE 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. KLEYLA
Special weather statement, Jul 23, 2:57 PM MDT, 1 hour 11 minutes before
COZ067-232130- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 257 PM MDT THU JUL 23 1998 ...THUNDERSTORMS INCREASING OVER SOUTHWESTERN DOUGLAS COUNTY... AT 250 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A THUNDERSTORM OVER WESTCREEK...OR ABOUT 27 MILES NORTHWEST OF COLORADO SPRINGS...MOVING EAST AT 10 MILES PER HOUR. THIS STORM WILL PRODUCE VERY HEAVY RAIN UP TO 2 INCHES PER HOUR ALONG WITH DANGEROUS LIGHTNING. PERSONS IN OR NEAR DEVIL'S HEAD...PERRY PARK AND WESTCREEK SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER AND MOVE TO A PLACE OF SAFETY IF BAD WEATHER APPROACHES. HEAVY RAINS MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES. AVOID T4HESE 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. KLEYLA
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 23, 4:12 PM MDT | Tornado Warning | BOU | Washington | 33 min |
| Jul 23, 4:23 PM MDT | Tornado Warning | BOU | Adams, Arapahoe | 22 min |
| Jul 23, 4:41 PM MDT | Tornado Warning | BOU | Morgan, Washington | 34 min |
| Jul 23, 5:11 PM MDT | Flash Flood Warning | BOU | Adams, Arapahoe | 2 hr |
| Jul 23, 5:12 PM MDT | Flash Flood Warning | BOU | Morgan, Washington | 2 hr |
| Jul 23, 5:47 PM MDT | Tornado Warning | BOU | Washington | 28 min |
Nearby
Tornado Warnings in Colorado, 1998Every tornado warning in 1998Tornadoes 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.