Alert archive / Arizona / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 31, NWS Phoenix, AZ

August 1, 1997Maricopa County, Pinal County, Arizona

NWS Phoenix, AZ issued this severe thunderstorm warning at Aug 1, 1997, 4:51 PM MST for Maricopa County, Pinal County, Arizona. It was in force for 59 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: Aug 1, 1997, 4:51 PM MST (23:51 UTC)
Expired: Aug 1, 1997, 5:50 PM MST
In force: 59 min
Issued by: NWS Phoenix, AZ
Area: Whole counties

Counties Maricopa County, AZ, Pinal County, AZ

The radar

The Phoenix radar (KIWA), 29 km from the middle of the area, began a volume at 23:53 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.

What was reported inside it

Time	Report	Where	Remark
Aug 1, 5:58 PM MST	Thunderstorm Wind 52	Florence, AZ	Spotter reported numerous trees were blown down, roofs damaged, and power poles downed. Some streets had to be closed due to live wires down across the roads. A tin roof completely lifted off an adobe home and was dumped into yard. The spotter observed sheet m

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

Tuscon, AZ (KTUS), launched 12:00Z, 11.9 hours before the alert went out and 143 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: 470 J/kg
Mixed-layer CIN: -106 J/kg
Mixed-layer LCL: 2151 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 5 m²/s²
0-3 km storm-relative helicity: 8 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KPHX 012352 RRA
SVRPHX
AZC013-021-020050-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
451 PM MST FRI AUG 1 1997

*  SEVERE THUNDERSTORM WARNING FOR
   EAST CENTRAL MARICOPA COUNTY IN CENTRAL ARIZONA
   NORTH CENTRAL PINAL COUNTY IN CENTRAL ARIZONA

*  UNTIL 550 PM MST

*  SOME LOCATIONS AFFECTED
   APACHE JUNCTION...MESA...GOLD CANYON RANCH AND QUEEN VALLEY
 
*  AT 445 PM MST RADAR INDICATED A SEVERE THUNDERSTORM
   BETWEEN APACHE JUNCTION AND SUPERIOR.  MOVEMENT WAS TO THE EAST AT
   10 MPH.

STRONG DAMAGING WINDS ARE LIKELY WITH THIS STORM.

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.

In the hours before

Special weather statement, Aug 1, 2:46 PM MST, 2 hours 5 minutes before

AZZ020>025-CAZ030>033-020130-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PHOENIX AZ
245 PM MST/PDT THU AUG 1 1997

...A MODERATE RISK  OF SEVERE THUNDERSTORMS OVER  NORTHWEST PINAL AND
SOUTHERN GILA COUNTIES...

...A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MARICOPA COUNTY...

A SIGNIFICANT INCREASE IN MID AND HIGH LEVEL MOISTURE HAS TAKEN PLACE
ACROSS SOUTH  CENTRAL  AND SOUTHWEST  ARIZONA TODAY.   THIS  MOISTURE
INCREASE...COUPLED  WITH VERY  WARM SURFACE  TEMPERATURES...WILL MAKE
FOR VERY  UNSTABLE ATMOSPHERIC  CONDITIONS OVER  THE  RISK AREA  THIS
AFTERNOON AND TONIGHT.

THE  MAIN THREAT  OF  SEVERE WEATHER  FOR  SOUTHERN GILA  COUNTY  AND
NORTHWEST  PINAL  COUNTY WILL  BE THIS  AFTERNOON  AND TONIGHT.   THE
GREATEST RISK FOR SEVERE  WEATHER OVER MARICOPA COUNTY WILL  BE LATER
TONIGHT...AFTER 7  PM.  ANY THUNDERSTORMS THAT  FORM OVER THE REST OF
THE  PHOENIX COUNTY  WARNING AREA  ARE NOT  EXPECTED TO  REACH SEVERE
LIMITS.

THE MAIN SEVERE  WEATHER THREAT  THIS AFTERNOON AND  TONIGHT WILL  BE
DAMAGING  WINDS  IN  EXCESS OF  57  MPH.   HEAVY  RAINFALL...FREQUENT
DANGEROUS  LIGHTNING...HAIL...AND  BLOWING  DUST  MAY  ACCOMPANY  THE
STRONGER STORMS.
....................................................................

THE OUTLOOK AREA INCLUDES THE FOLLOWING COUNTIES...

IN ARIZONA                     IN CALIFORNIA

MARICOPA          YUMA         IMPERIAL
SOUTHERN GILA     LA PAZ       CENTRAL/EASTERN RIVERSIDE
NORTHWEST PINAL

KOCH

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 1, 11:58 AM MST	Severe Thunderstorm Warning	PSR	Pinal	8 hr

Nearby

Severe Thunderstorm Warnings in Arizona, 1997 Every severe thunderstorm warning in 1997

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.