Alert archive / Arizona / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 3, NWS Flagstaff, AZ

July 21, 1990Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Jul 21, 1990, 4:50 PM MST for Yavapai County, Arizona. It was in force for 55 min.

The area

The counties it named.

The facts

Issued: Jul 21, 1990, 4:50 PM MST (23:50 UTC)
Expired: Jul 21, 1990, 5:45 PM MST
In force: 55 min
Issued by: NWS Flagstaff, AZ
Area: Whole counties

County Yavapai County, AZ

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Winslow (Autob), AZ (KINW), launched 12:00Z, 11.8 hours before the alert went out and 176 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: 200 J/kg
Mixed-layer CIN: -148 J/kg
Mixed-layer LCL: 2123 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 80 m²/s²
0-3 km storm-relative helicity: 118 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPHX 212351
SVRPHX
AZC025-220045-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHOENIX ARIZONA
450 PM MST SAT JUL 21 1990
 
THE NATIONAL WEATHER SERVICE IN PHOENIX ARIZONA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  545 PM MST
FOR THE FOLLOWING LOCATIONS......
 
IN WEST CENTRAL ARIZONA
 
   ...CENTRAL YAVAPAI COUNTY
 
AT 445 PM RADAR AND SURFACE REPORTS INDICATED THAT A THUNDERSTORM WITH
VERY HEAVY RAIN AND POSSIBLY STRONG DAMAGING WINDS WAS APPROACHING THE
CITY OF PRESCOTT. THIS STORM WAS MOVING TOWARDS THE SOUTH AT ABOUT 20
MPH.
 
SEVERE THUNDERSTORMS CAUSE DAMAGING WINDS...LARGE HAIL AND DEADLY
LIGHTNING. MOVE INSIDE A REINFORCED BUILDING OR STORM SHELTER. GO TO
AN INTERIOR ROOM OR HALLWAY ON THE LOWEST FLOOR. STAY AWAY FROM
WINDOWS.
 
WATCH OUT FOR FLASH FLOODING. STAY AWAY FROM STREAMS AND AVOID NARROW
STEEP WALLED CANYONS. DONT DRIVE ACROSS FLOODED STREAMS OR WASHES...
OR INTO FLOODED CITY STREETS OR UNDERPASSES.

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, Jul 21, 1:47 PM MST, 3 hours 3 minutes before

AZZ005-212300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
145 PM MST SAT JUL 21 1990

THUNDERSTORMS ARE CONTINUING TO DEVELOP RAPIDLY IN NORTHERN ARIZONA.
JUST BEFORE 130 PM A COOPERATIVE OBSERVER IN PAGE REPORTED HEAVY                RAINFALL AND PEA SIZED HAIL.   WIND WAS BLOWING AT 20 MPH AND
GUSTING TO 41 MPH.  AN OFF DUTY WEATHER SERVICE EMPLOYEE IN REPORTED
RAIN AND PEA SIZED HAIL IN EAST FLAGSTAFF AT 140 PM.

THUNDERSTORMS WILL CONTINUE TO DEVELOP AND MOVE ACROSS NORTHERN
ARIZONA THIS AFTERNOON AND EARLY EVENING.

.REMEMBER...THUNDERSTORMS CAN PRODUCE DAMAGINMG WIND...BLOWING
DUST...DANGEROUS LIGHTNING...HAIL AND "LOCALLY HEAVY RAINFALL.

PETERSON

Nearby

Severe Thunderstorm Warnings in Arizona, 1990 Every severe thunderstorm warning in 1990

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.