Alert archive / Arizona / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 19, NWS Flagstaff, AZ

July 20, 1998Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Jul 20, 1998, 8:40 PM MST for Yavapai County, Arizona. It was in force for 45 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: Jul 20, 1998, 8:40 PM MST (03:40 UTC)
Expired: Jul 20, 1998, 9:25 PM MST
In force: 45 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 03:40 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
Jul 20, 8:45 PM MST	Hail 1.25	Camp Verde, AZ	A weather spotter reported 1.25 inch diameter hail in Camp Verde.

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

Flgstf/Belemont, AZ (KFGZ), launched 00:00Z, 3.7 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 534 J/kg
Mixed-layer CIN: -46 J/kg
Mixed-layer LCL: 1738 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: -12 m²/s²
0-3 km storm-relative helicity: 85 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

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 Jul 20, 8:30 PM MST, 10 minutes earlier.

Area forecast discussion, Jul 20, 8:30 PM MST, 10 minutes before

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
830 PM MST MON JUL 20 1998

SYNOPSIS...AN AREA OF HIGH PRESSURE NORTH OF THE STATE WILL CONTINUE
TO GENERATE A RELATIVELY MOIST SOUTHEASTERLY FLOW OVER ARIZONA THE
NEXT FEW DAYS. THIS WILL RESULT IN A CONTINUED CHANCE OF AFTERNOON
AND EVENING THUNDERSTORMS...PARTICULARLY OVER THE MOGOLLON RIM AND
WHITE MOUNTAINS.

DISCUSSION...BUSY EVE THO NOT NEARLY AS BAD AS LAST NIGHT.  EASTERLY
WAVE RESPONSIBLE FOR YESTERDAY/S ACTIVE WEATHER NOW IN EXTREME SERN
CA.  THUS...DYNAMICS ACROSS NRN AZ DOWN FROM YESTERDAY THO PLENTY OF
MOISTURE INTERACTING WITH FAVORABLE THERMODYNAMIC PROFILES FOR DECENT
AMOUNT OF ACTIVITY TONIGHT NONETHELESS.  NOT MUCH CHANCE TO LOOK AT
NEW DATA THO SEE NO REASON FOR ANY SIGNIFICANT CHANGES NEXT FEW DAYS.
WILL TAKE A LOOK AT THE FIRST PD AND MAKE ANY NECESSARY ADJUSTMENTS.
KHW

FLG 2424  INW 2111
FLG...NONE.

In the hours before

Local storm report, Jul 20, 4:09 PM MST, 4 hours 31 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>

Local storm report, Jul 20, 4:09 PM MST, 4 hours 31 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>

The office that day

Everything else NWS Flagstaff, AZ issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 20, 7:14 PM MST	Severe Thunderstorm Warning	FGZ	Gila	46 min
Jul 20, 8:04 PM MST	Severe Thunderstorm Warning	FGZ	Gila	46 min
Jul 21, 1:06 AM MST	Flash Flood Warning	FGZ	Coconino	3 hr

Nearby

Severe Thunderstorm Warnings in Arizona, 1998 Every severe thunderstorm warning in 1998

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.