Alert archive / Colorado / Severe Thunderstorm Warnings in 2002
Severe Thunderstorm Warning 22, NWS Grand Junction, CO
NWS Grand Junction, CO issued this severe thunderstorm warning at Aug 20, 2002, 9:06 PM MDT for Mesa County, Colorado. It was in force for 24 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 20, 2002, 9:06 PM MDT (03:06 UTC)
- Expired
- Aug 20, 2002, 9:30 PM MDT
- In force
- 24 min
- Issued by
- NWS Grand Junction, CO
- Area
- Counties, with a storm outline in the text
County Mesa County, CO
The radar
The Grand Junction radar (KGJX), 22 km from the middle of the area, began a volume at 03:07 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.
The nearest sounding before it
Grand Junction, CO (KGJT), launched 00:00Z, 3.1 hours before the alert went out and 13 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
- 413 J/kg
- Mixed-layer CIN
- -107 J/kg
- Mixed-layer LCL
- 1704 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- -39 m²/s²
- 0-3 km storm-relative helicity
- 25 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.4
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 Grand Junction, CO wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 20, 2:34 PM MDT, 6 hours 32 minutes earlier.
Area forecast discussion, Aug 20, 2:34 PM MDT, 6 hours 32 minutes before
WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 234 PM MDT TUE AUG 20 2002 BROAD TROUGH OF LOW PRESSURE SETTING UP OVER THE PACIFIC NORTHWEST HAS PLACED EASTERN UTAH AND WESTERN COLORADO UNDER THE INFLUENCE OF MOIST SW FLOW TODAY (MORNING KGJT SOUNDING SHOWED PRECIPITABLE WATER IN EXCESS OF 1.2 INCHES). SCATTERED SHOWERS AND THUNDERSTORMS WILL LIKELY LINGER INTO THE LATE NIGHT HOURS AS A COUPLE MORE WEAK SHRTWVS MOVE THROUGH THE AREA. WL CONT THE FLASH FLOOD WATCH FOR LA PLATA AND GARFIELD COUNTIES IN WESTERN COLORADO DUE TO THE RAINFALL EARLIER TODAY...WITH MORE SHOWERS AND THUNDERSTORMS STILL A GOOD POSSIBILITY. OVERALL TREND IN THE NEW MODELS RUNS CONTS TO ADVERTISE DRIER AIR SWEEPING THROUGH THE AREA BY LATE TONIGHT AND DURING THE DAY ON WEDNESDAY. HOWEVER...LOW LEVEL MOISTURE WILL BE SLOWER TO ERODE... AND WARMER AFTERNOON TEMPS WL STILL LEAD TO THE POSSIBILITY OF ADDITIONAL SHOWERS AND THUNDERSTORMS BY THE AFTERNOON HOURS. MAIN FOCUS OF CONVECTION THOUGH IS EXPECTED TO BE CONFINED TO THE HIGHER TERRAIN AND OVER THE SOUTHERN VALLEYS...CLOSER TO THE DEEPER MOISTURE. SIMILAR TRENDS WL CONT ON THURSDAY WITH TEMPS SLOWLY CREEPING BACK UP TO ABOVE NORMAL READINGS BY THE END OF THE WEEK. JDC (SAT-TUE)...MOSTLY DRY. UPPER LOW LINGERING NEAR OR/CA/NV POINT EXPECTED TO TO LIFT OUT DURING THE WEEKEND AS UPPER HIGH BUILDS WEST ACROSS DESERT SOUTHWEST. DRIER SOUTHWEST FLOW SAT-SUN AS MOISTURE APPEARS LIMITED BELOW 500 MB. HOWEVER...POSSIBLE WEAK JET SUPPORT ASSOCIATED WITH EJECTING UPPER LOW PLUS DAYTIME HEATING AND ANY WEAK IMPULSES ENOUGH TO KEEP MENTION OF SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS FOR THE MTNS SAT-SUN. ECWMF THEN KEEPS A TROUGH NEAR PAC NW COAST EARLY NEXT WEEK WHILE AVN HAS REMNANTS OF UPPER LOW OVER THE NORTHERN ROCKIES WITH WEAK TROUGHING FROM WY BACK TO SRN CA. WILL KEEP A SLIGHT CHANCE OF THUNDERSTORMS FOR THE MTNS MON-TUE. LITTLE CHANGE IN TEMPS. JAD .GJT...NONE.
The office that day
Everything else NWS Grand Junction, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 20, 6:28 PM MDT | Severe Thunderstorm Warning | GJT | San Miguel | 47 min |
| Aug 20, 7:07 PM MDT | Severe Thunderstorm Warning | GJT | Montrose, San Miguel | 38 min |
| Aug 20, 9:16 PM MDT | Flash Flood Warning | GJT | La Plata | 3 hr |
| Aug 21, 1:23 PM MDT | Flash Flood Warning | GJT | La Plata | 3 hr |
Nearby
Severe Thunderstorm Warnings in Colorado, 2002Every severe thunderstorm warning in 2002
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; radar from the NEXRAD Level II archive.