Alert archive / Arizona / Severe Thunderstorm Warnings in 2001
Severe Thunderstorm Warning 92, NWS Flagstaff, AZ
NWS Flagstaff, AZ issued this severe thunderstorm warning at Aug 21, 2001, 1:13 PM MDT for Navajo County, Arizona. It was in force for 32 min. No storm report in the archive falls 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.
The facts
- Issued
- Aug 21, 2001, 1:13 PM MDT (19:13 UTC)
- Expired
- Aug 21, 2001, 1:45 PM MDT
- In force
- 32 min
- Issued by
- NWS Flagstaff, AZ
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
County Navajo County, AZ
The nearest sounding before it
Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 7.2 hours before the alert went out and 231 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
- 160 J/kg
- Mixed-layer CIN
- -81 J/kg
- Mixed-layer LCL
- 1422 m above ground
- 0-6 km bulk shear
- 6 kt
- 0-1 km storm-relative helicity
- 13 m²/s²
- 0-3 km storm-relative helicity
- -15 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
769 WUUS55 KFGZ 211915 SVRFLG AZC017-211945- BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE FLAGSTAFF AZ 1213 PM MST TUE AUG 21 2001 113 PM MDT THE NATIONAL WEATHER SERVICE HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... EXTREME NORTHEASTERN NAVAJO COUNTY IN ARIZONA * UNTIL 1245 PM MST (145 PM MDT) * AT 1213 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM OVER EXTREME NORTHEASTERN NAVAJO COUNTY ABOUT 11 MILES NORTHEAST OF KAYENTA...MOVING NORTH NORTHEAST AT 10 MPH. * THIS STORM WILL MOVE OVER THE MONUMENT VALLEY AREA BY 125 PM MDT. VERY LARGE HAIL IS POSSIBLE WITH THIS SEVERE THUNDERSTORM. IF YOU ARE IN THE PATH OF THE STORM... MOVE TO A SUBSTANTIAL SHELTER. REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE. LAT...LON 3683 11018 3675 11015 3679 10999 3690 11005
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 Flagstaff, AZ wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 21, 10:10 AM MDT, 3 hours 3 minutes earlier.
Area forecast discussion, Aug 21, 10:10 AM MDT, 3 hours 3 minutes before
NORTHERN ARIZONA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FLAGSTAFF AZ 910 AM MST TUE AUG 21 2001 .SYNOPSIS...A TROUGH OF LOW PRESSURE WILL MOVE ACROSS THE REGION TODAY. AHEAD OF THIS SYSTEM...SHOWERS AND THUNDERSTORMS WILL DEVELOP AGAIN THIS AFTERNOON. BY WEDNESDAY...THE LOW PRESSURE SYSTEM WILL HAVE MOVED TO THE EAST. EXPECT A DRYING AND WARMING TREND OVER NORTHERN ARIZONA WITH MOSTLY SUNNY DAYS AND CLEAR NIGHTS LASTING INTO THE WEEKEND. .DISCUSSION...RATHER DISTINCT AND DEFINITELY STRONGER THAN FORECAST TROUGH ON ITS WAY THROUGH THE GREAT BASIN TOWARDS ARIZONA. MOIST AND UNSTABLE AIR STILL EXISTS OVER THE STATE AHEAD OF THIS TROUGH...AND THAT IS WHERE THE PROBLEMS START. MORNING SOUNDINGS...ALTHOUGH NOT SOAKING WET...ARE VERY UNSTABLE. THE HEATING OF THE DAY ALONE WILL BE ENOUGH FOR SCATTERED STRONG STORMS TODAY. ADD IN THE SYNOPTIC SCALE LIFT ASSOCIATED WITH TROUGH AS WELL AS THE SHEAR...AND YOU HAVE INGREDIENTS FOR A POTENTIALLY BIG DAY. CONVECTION ALREADY GOING OVER THE NORTHERN ZONES...AND WOULD EXPECT THIS TO BECOME MORE WIDESPREAD LATER THIS MORNING. THE ONLY LIMITING FACTOR IS THE DRIER THAN NORMAL AIR ACROSS THE REGION. THEREFORE...THE SCATTERED POPS ARE A GOOD WAY TO GO...BUT THE STORMS THAT DO DEVELOP COULD BE BIG ONES. AFTER THIS TROUGH PASSAGE...IT DRIES OUT SO QUICKLY AND COMPLETELY...THAT NO FURTHER MENTION OF PRECIPITATION IS NEEDED. PETERSON. .FGZ...NONE.
In the hours before
Special weather statement, Aug 21, 10:15 AM MDT, 2 hours 58 minutes before
AZZ004>018-037>040-211930- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE FLAGSTAFF AZ 915 AM MST TUE AUG 21 2001 ...STRONG STORMS...SOME WITH WITH LARGE HAIL AND HIGH WINDS...ARE EXPECTED OVER NORTHERN ARIZONA TODAY... A MOIST AND UNSTABLE AIR MASS LIES OVER ARIZONA AHEAD OF AN APPROACHING VIGOROUS UPPER LEVEL DISTURBANCE. EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP ONCE AGAIN TODAY OVER MUCH OF NORTHERN ARIZONA. BY THIS AFTERNOON AND TONIGHT...STORMS MAY BECOME MORE ORGANIZED WITH A FEW STORMS REACHING SEVERE LEVELS. THE MAIN THREAT FROM THESE STORMS WILL BE STRONG WINDS OF UP TO 60 MPH AND LARGE HAIL UP TO ONE INCH IN DIAMETER. BECAUSE OF THE STRONG DYNAMICS ASSOCIATED WITH THIS APPROACHING SYSTEM...THUNDERSTORMS MAY BE SLOW TO DISSIPATE THIS EVENING. SOME CONVECTION MAY LAST WELL INTO THE NIGHT...ESPECIALLY OVER THE EASTERN PORTIONS OF THE STATE.
The office that day
Everything else NWS Flagstaff, AZ issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 20, 6:12 PM MDT | Flash Flood Warning | FGZ | Apache | |
| Aug 20, 6:31 PM MDT | Severe Thunderstorm Warning | FGZ | Navajo | 29 min |
| Aug 20, 7:08 PM MDT | Severe Thunderstorm Warning | FGZ | Navajo | 37 min |
| Aug 20, 9:27 PM MDT | Severe Thunderstorm Warning | FGZ | Navajo | 33 min |
| Aug 20, 9:27 PM MDT | Severe Thunderstorm Warning | FGZ | Apache | 33 min |
| Aug 21, 2:30 PM MDT | Severe Thunderstorm Warning | FGZ | Apache | 30 min |
Nearby
Severe Thunderstorm Warnings in Arizona, 2001Every severe thunderstorm warning in 2001
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.