Alert archive / Colorado / Severe Thunderstorm Warnings in 1999
Severe Thunderstorm Warning 45, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jun 10, 1999, 1:54 PM MDT for Jefferson 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
- Jun 10, 1999, 1:54 PM MDT (19:54 UTC)
- Expired
- Jun 10, 1999, 2:30 PM MDT
- In force
- 36 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
County Jefferson County, CO
The radar
The Denver radar (KFTG), 64 km from the middle of the area, began a volume at 19:53 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 |
|---|---|---|---|
| Jun 10, 2:05 PM MDT | Hail 1 | Evergreen, CO | |
| Jun 10, 2:20 PM MDT | Hail 1.75 | Golden, 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 nearest sounding before it
Denver, CO (KDNR), launched 12:00Z, 7.9 hours before the alert went out and 176 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
- 125 J/kg
- Mixed-layer CIN
- -64 J/kg
- Mixed-layer LCL
- 690 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 7 m²/s²
- 0-3 km storm-relative helicity
- 69 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 severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Denver/Boulder, CO wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 10, 1:45 AM MDT, 12 hours 9 minutes earlier.
Area forecast discussion, Jun 10, 1:45 AM MDT, 12 hours 9 minutes before
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</html>In the hours before
Special weather statement, Jun 10, 10:45 AM MDT, 3 hours 9 minutes before
COZ030-032>050-110600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 1045 AM MDT THU JUN 10 1999 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: A WEAK AND MOIST UPSLOPE FLOW WILL REMAIN OVER THE FRONT RANGE FOOTHILLS AND NORTHEAST PLAINS THROUGH TONIGHT. THE ATMOSPHERE REMAINS RATHER STABLE LATE THIS MORNING DUE TO THE CURRENT CLOUD COVER. SOME SURFACE HEATING IS EXPECTED TO OCCUR THIS AFTERNOON AS CLOUDS BREAK UP AND ALLOWING THE ATMOSPHERE TO BECOME MORE UNSTABLE. AN UPPER LEVEL DISTURBANCE WILL ALSO MOVE OVER THE REGION TONIGHT WHICH WILL HELP TO ENHANCE...AND ALLOW STORMS TO CONTINUE THROUGH MUCH OF THE NIGHT OVER THE PLAINS. STORM DEVELOPMENT WILL INITIALLY BEGIN OVER THE MOUNTAINS AND FOOTHILLS BY NOON AND GRADUALLY SPREAD OVER THE URBAN CORRIDOR AROUND MID AFTERNOON...THEN FURTHER OVER THE PLAINS LATE AFTERNOON AND EARLY EVENING. THE MAIN THREAT FROM THESE STORMS WILL BE HEAVY RAIN AND SMALL HAIL. HOWEVER...AN ISOLATED SEVERE STORM MAY POP UP WITH HAIL UP TO 1 INCH IN DIAMETER. THESE STRONGEST STORMS WILL BE OVER THE PALMER DIVIDE AND LINCOLN COUNTY. SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY...BUT ANY HAIL AND RAIN REPORTS WILL BE APPRECIATED. ENTREKIN
Special weather statement, Jun 10, 10:45 AM MDT, 3 hours 9 minutes before
COZ030-032>050-090600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 1045 AM MDT THU JUN 10 1999 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: A WEAK AND MOIST UPSLOPE FLOW WILL REMAIN OVER THE FRONT RANGE FOOTHILLS AND NORTHEAST PLAINS THROUGH TONIGHT. THE ATMOSPHERE REMAINS RATHER STABLE LATE THIS MORNING DUE TO THE CURRENT CLOUD COVER. SOME SURFACE HEATING IS EXPECTED TO OCCUR THIS AFTERNOON AS CLOUDS BREAK UP AND ALLOWING THE ATMOSPHERE TO BECOME MORE UNSTABLE. AN UPPER LEVEL DISTURBANCE WILL ALSO MOVE OVER THE REGION TONIGHT WHICH WILL HELP TO ENHANCE...AND ALLOW STORMS TO CONTINUE THROUGH MUCH OF THE NIGHT OVER THE PLAINS. STORM DEVELOPMENT WILL INITIALLY BEGIN OVER THE MOUNTAINS AND FOOTHILLS BY NOON AND GRADUALLY SPREAD OVER THE URBAN CORRIDOR AROUND MID AFTERNOON...THEN FURTHER OVER THE PLAINS LATE AFTERNOON AND EARLY EVENING. THE MAIN THREAT FROM THESE STORMS WILL BE HEAVY RAIN AND SMALL HAIL. HOWEVER...AN ISOLATED SEVERE STORM MAY POP UP WITH HAIL UP TO 1 INCH IN DIAMETER. THESE STRONGEST STORMS WILL BE OVER THE PALMER DIVIDE AND LINCOLN COUNTY. SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY...BUT ANY HAIL AND RAIN REPORTS WILL BE APPRECIATED. ENTREKIN
Special weather statement, Jun 10, 10:45 AM MDT, 3 hours 9 minutes before
COZ030-032>050-090600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 1045 AM MDT THU JUN 10 1999 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: A WEAK AND MOIST UPSLOPE FLOW WILL REMAIN OVER THE FRONT RANGE FOOTHILLS AND NORTHEAST PLAINS THROUGH TONIGHT. THE ATMOSPHERE REMAINS RATHER STABLE LATE THIS MORNING DUE TO THE CURRENT CLOUD COVER. SOME SURFACE HEATING IS EXPECTED TO OCCUR THIS AFTERNOON AS CLOUDS BREAK UP AND ALLOWING THE ATMOSPHERE TO BECOME MORE UNSTABLE. AN UPPER LEVEL DISTURBANCE WILL ALSO MOVE OVER THE REGION TONIGHT WHICH WILL HELP TO ENHANCE...AND ALLOW STORMS TO CONTINUE THROUGH MUCH OF THE NIGHT OVER THE PLAINS. STORM DEVELOPMENT WILL INITIALLY BEGIN OVER THE MOUNTAINS AND FOOTHILLS BY NOON AND GRADUALLY SPREAD OVER THE URBAN CORRIDOR AROUND MID AFTERNOON...THEN FURTHER OVER THE PLAINS LATE AFTERNOON AND EARLY EVENING. THE MAIN THREAT FROM THESE STORMS WILL BE HEAVY RAIN AND SMALL HAIL. HOWEVER...AN ISOLATED SEVERE STORM MAY POP UP WITH HAIL UP TO 1 INCH IN DIAMETER. THESE STRONGEST STORMS WILL BE OVER THE PALMER DIVIDE AND LINCOLN COUNTY. SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY...BUT ANY HAIL AND RAIN REPORTS WILL BE APPRECIATED. ENTREKIN
Special weather statement, Jun 10, 10:45 AM MDT, 3 hours 9 minutes before
COZ030-032>050-110600- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 1045 AM MDT THU JUN 10 1999 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: A WEAK AND MOIST UPSLOPE FLOW WILL REMAIN OVER THE FRONT RANGE FOOTHILLS AND NORTHEAST PLAINS THROUGH TONIGHT. THE ATMOSPHERE REMAINS RATHER STABLE LATE THIS MORNING DUE TO THE CURRENT CLOUD COVER. SOME SURFACE HEATING IS EXPECTED TO OCCUR THIS AFTERNOON AS CLOUDS BREAK UP AND ALLOWING THE ATMOSPHERE TO BECOME MORE UNSTABLE. AN UPPER LEVEL DISTURBANCE WILL ALSO MOVE OVER THE REGION TONIGHT WHICH WILL HELP TO ENHANCE...AND ALLOW STORMS TO CONTINUE THROUGH MUCH OF THE NIGHT OVER THE PLAINS. STORM DEVELOPMENT WILL INITIALLY BEGIN OVER THE MOUNTAINS AND FOOTHILLS BY NOON AND GRADUALLY SPREAD OVER THE URBAN CORRIDOR AROUND MID AFTERNOON...THEN FURTHER OVER THE PLAINS LATE AFTERNOON AND EARLY EVENING. THE MAIN THREAT FROM THESE STORMS WILL BE HEAVY RAIN AND SMALL HAIL. HOWEVER...AN ISOLATED SEVERE STORM MAY POP UP WITH HAIL UP TO 1 INCH IN DIAMETER. THESE STRONGEST STORMS WILL BE OVER THE PALMER DIVIDE AND LINCOLN COUNTY. SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY...BUT ANY HAIL AND RAIN REPORTS WILL BE APPRECIATED. ENTREKIN
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 10, 2:27 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Denver, Jefferson | 33 min |
| Jun 10, 3:00 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Denver | 45 min |
| Jun 10, 3:42 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Denver | 33 min |
| Jun 10, 4:06 PM MDT | Tornado Warning | BOU | Adams | 24 min |
| Jun 10, 4:10 PM MDT | Severe Thunderstorm Warning | BOU | Douglas | 50 min |
| Jun 10, 4:27 PM MDT | Tornado Warning | BOU | Adams | 33 min |
| Jun 10, 4:59 PM MDT | Tornado Warning | BOU | Adams | 31 min |
| Jun 10, 5:27 PM MDT | Tornado Warning | BOU | Adams, Arapahoe | 33 min |
Nearby
Severe Thunderstorm Warnings in Colorado, 1999Every severe thunderstorm warning in 1999
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.