Alert archive / Arizona / Severe Thunderstorm Warnings in 1999
Severe Thunderstorm Warning 76, NWS Flagstaff, AZ
NWS Flagstaff, AZ issued this severe thunderstorm warning at Sep 16, 1999, 2:54 PM MST for Yavapai County, Arizona. It was in force for 46 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
- Sep 16, 1999, 2:54 PM MST (21:54 UTC)
- Expired
- Sep 16, 1999, 3:40 PM MST
- In force
- 46 min
- Issued by
- NWS Flagstaff, AZ
- Area
- Whole counties
County Yavapai County, AZ
The radar
The Flagstaff radar (KFSX), 124 km from the middle of the area, began a volume at 21:53 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.
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, 9.9 hours before the alert went out and 98 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 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 Sep 16, 2:30 PM MST, 24 minutes earlier.
Area forecast discussion, Sep 16, 2:30 PM MST, 24 minutes before
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Service Notice</title>
<link rel="stylesheet" href="index.css">
</head>
<body>
<main class="wrap">
<section class="card" role="status" aria-live="polite">
<div class="status" id="status">Temporary Notice</div>
<h1 id="headline">This service is currently unavailable.</h1>
<p id="message1">
The site you requested is temporarily down for maintenance or an unexpected outage.
</p>
<p id="message2">
Please try again in a few minutes.
</p>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html>In the hours before
Special weather statement, Sep 16, 9:30 AM MST, 5 hours 24 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, 5 hours 24 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, 1:59 PM MST | Tornado Warning | FGZ | Coconino | 16 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, 4:16 PM MST | Severe Thunderstorm Warning | FGZ | Yavapai | 49 min |
Nearby
Severe Thunderstorm Warnings in Arizona, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.