Alert archive / Arizona / Tornado Warnings in 1999
Tornado Warning 7, NWS Flagstaff, AZ
NWS Flagstaff, AZ issued this tornado warning at Sep 16, 1999, 1:59 PM MST for Coconino County, Arizona. It was in force for 16 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
- Sep 16, 1999, 1:59 PM MST (20:59 UTC)
- Expired
- Sep 16, 1999, 2:15 PM MST
- In force
- 16 min
- Issued by
- NWS Flagstaff, AZ
- Area
- Whole counties
County Coconino County, AZ
The radar
The Flagstaff radar (KFSX), 150 km from the middle of the area, began a volume at 20:59 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 |
|---|---|---|---|
| Sep 16, 2:00 PM MST | Tornado F0 | Winona, AZ | A witness of this brief tornado was interviewed by a channel 3, a local TV station, the day of the event. In the interview, the witness described the rope like tornado descending from the cloud, and touching the ground twice in an open field. |
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 watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Sep 16, 12:00 PM MST | Severe Thunderstorm Watch | SPC | 7 hr |
The nearest sounding before it
Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 9.0 hours before the alert went out and 68 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
- 563 J/kg
- Mixed-layer CIN
- -49 J/kg
- Mixed-layer LCL
- 1072 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 24 m²/s²
- 0-3 km storm-relative helicity
- 67 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.5
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.
NWS Flagstaff, AZ wrote its last area forecast discussion before this tornado warning went out at Sep 16, 9:15 AM MST, 4 hours 44 minutes earlier.
Area forecast discussion, Sep 16, 9:15 AM MST, 4 hours 44 minutes before
NORTHERN ARIZONA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FLAGSTAFF AZ 915 AM MST THU SEP 16 1999 SYNOPSIS...A WEAK TROUGH WILL TRIGGER THUNDERSTORMS ACROSS NORTHWESTERN ARIZONA TODAY. AS MOISTURE CONTINUES TO COVER MUCH OF THE STATE...SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP THROUGH FRIDAY. OVER THE WEEKEND SLOW DRYING IS EXPECTED TO MOVE IN FROM THE WEST WITH THUNDERSTORM ACTIVITY GRADUALLY SHIFTING EAST. DISCUSSION...FORECAST FOCUS TODAY WILL BE ON THE SHORTWAVE MOVING THROUGH SRN NEVADA. THUNDERSTORMS BEGAN DEVELOPING IN MOHAVE COUNTY BY 13Z...SO IT LOOKS LIKE ANOTHER BUSY DAY ACROSS NORTHERN ARIZONA. THE MORNING FGZ SOUNDING IS QUITE UNSTABLE AND CONSERVATIVE MOISTURE MODIFICATIONS RESULT IN A CAPE AROUND 800. NOT BAD FOR 7KFT AND CU ARE ALREADY DEVELOPING OUTSIDE. LOOKS LIKE THE ACTIVE AREA EARLY THIS MORNING WILL BE NORTHWESTERN QUADRANT OF THE FLG CWA THROUGH THE MORNING AND EARLY AFTERNOON. LATER...THE ACTIVITY LOOKS TO SHIFT DOWN THE RIM...BUT STORMS ARE NOT LIKELY TO BE AS INTENSE OUT THERE. WILL ISSUE AN UPDATE THIS MORNING TO REFLECT THE TRENDS EXPECTED IN THE NORTHWEST AND WEST-CENTRAL CWA. FOR NOW... THE REST OF THE FORECAST LOOKS FINE. PEREZ .FLG...NONE.
In the hours before
Special weather statement, Sep 16, 9:30 AM MST, 4 hours 29 minutes before
AZZ004>018-037>040-162000- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE FLAGSTAFF AZ 930 AM MST THU SEP 16 1999 ...THUNDERSTORMS LIKELY ACROSS NORTHWESTERN ARIZONA TODAY... ...SPOTTER REPORTS REQUESTED... DISCUSSION...ANOTHER WEAK TROUGH WILL MOVE ACROSS NORTHERN ARIZONA TODAY. THE AIR MASS OVER THE NORTHLAND REMAINS UNSTABLE ALONG THE KAIBAB AND COCONINO PLATEAUS...THE WESTERN MOGOLLON RIM AND THE NORTHERN HALF OF YAVAPAI COUNTY. WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BEGIN DEVELOPING BY MID MORNING IN THESE AREAS. THE FLOW ALOFT TODAY IS SOMEWHAT SUPPORTIVE OF ORGANIZED STORMS... ESPECIALLY WEST OF A LINE FROM PAGE TO FLAGSTAFF TO PRESCOTT. HAIL...GUSTY WINDS AND LOCALLY HEAVY RAIN WILL OCCUR IN SOME OF THE STRONGER STORMS. MOST OF THE STORM ACTIVITY WILL BE TAPERING OFF OR MOVING INTO EASTERN ARIZONA...AND WEAKENING...LATER THIS EVENING. PEREZ
Special weather statement, Sep 16, 9:30 AM MST, 4 hours 29 minutes before
AZZ004>018-037>040-162000- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE FLAGSTAFF AZ 930 AM MST THU SEP 16 1999 ...THUNDERSTORMS LIKELY ACROSS NORTHWESTERN ARIZONA TODAY... ...SPOTTER REPORTS REQUESTED... DISCUSSION...ANOTHER WEAK TROUGH WILL MOVE ACROSS NORTHERN ARIZONA TODAY. THE AIR MASS OVER THE NORTHLAND REMAINS UNSTABLE ALONG THE KAIBAB AND COCONINO PLATEAUS...THE WESTERN MOGOLLON RIM AND THE NORTHERN HALF OF YAVAPAI COUNTY. WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BEGIN DEVELOPING BY MID MORNING IN THESE AREAS. THE FLOW ALOFT TODAY IS SOMEWHAT SUPPORTIVE OF ORGANIZED STORMS... ESPECIALLY WEST OF A LINE FROM PAGE TO FLAGSTAFF TO PRESCOTT. HAIL...GUSTY WINDS AND LOCALLY HEAVY RAIN WILL OCCUR IN SOME OF THE STRONGER STORMS. MOST OF THE STORM ACTIVITY WILL BE TAPERING OFF OR MOVING INTO EASTERN ARIZONA...AND WEAKENING...LATER THIS EVENING. PEREZ
The office that day
Everything else NWS Flagstaff, AZ issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 15, 5:12 PM MST | Tornado Warning | FGZ | Yavapai | 33 min |
| Sep 15, 5:42 PM MST | Severe Thunderstorm Warning | FGZ | Yavapai | 33 min |
| Sep 16, 11:15 AM MST | Severe Thunderstorm Warning | FGZ | Coconino | 30 min |
| Sep 16, 11:33 AM MST | Severe Thunderstorm Warning | FGZ | Coconino | 47 min |
| Sep 16, 12:19 PM MST | Severe Thunderstorm Warning | FGZ | Yavapai | 41 min |
| Sep 16, 12:35 PM MST | Severe Thunderstorm Warning | FGZ | Coconino | 45 min |
| Sep 16, 12:42 PM MST | Severe Thunderstorm Warning | FGZ | Coconino | 48 min |
| Sep 16, 1:17 PM MST | Tornado Warning | FGZ | Coconino | 33 min |
| Sep 16, 2:24 PM MST | Tornado Warning | FGZ | Coconino | 11 min |
| Sep 16, 2:30 PM MST | Severe Thunderstorm Warning | FGZ | Navajo | 50 min |
| Sep 16, 2:54 PM MST | Severe Thunderstorm Warning | FGZ | Yavapai | 46 min |
| Sep 16, 4:16 PM MST | Severe Thunderstorm Warning | FGZ | Yavapai | 49 min |
Nearby
Tornado Warnings in Arizona, 1999Every tornado warning in 1999Tornadoes 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.