Alert archive / Arizona / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 13, NWS Flagstaff, AZ

May 21, 1997Navajo County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at May 21, 1997, 3:45 PM MDT for Navajo County, Arizona. It was in force for 45 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
May 21, 1997, 3:45 PM MDT (21:45 UTC)
Expired
May 21, 1997, 4:30 PM MDT
In force
45 min
Issued by
NWS Flagstaff, AZ
Area
Whole counties

County Navajo County, AZ

The radar

The Flagstaff radar (KFSX), 122 km from the middle of the area, began a volume at 21:45 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 nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 9.8 hours before the alert went out and 136 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-pSkew-T log-p diagram, Flgstf/Belemont, AZ at 12:00Z on 1997-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 12:00Z on 1997-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -48 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1190 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
-48 m²/s²
0-3 km storm-relative helicity
-28 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 KFLG 212148
SVRFLG
AZC017-212230-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
245 PM MST WED MAY 21 1997

THE NATIONAL WEATHER SERVICE IN FLAGSTAFF AZ HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 330 PM MST
FOR PEOPLE IN THE FOLLOWING LOCATION...

IN NORTHEASTERN ARIZONA

   ...SOUTHERN NAVAJO COUNTY
 
AT 245 PM MST...A SEVERE THUNDERSTORM WAS INDICATED BY FLAGSTAFF
DOPPLER RADAR 39 MILES SOUTH OF WINSLOW OR 4 MILES WEST NORTHWEST
OF HEBER MOVING NORTH NORTHWEST AT 10 MPH.  RADAR INDICATES THAT
HAIL AROUND ONE INCH IN DIAMETER IS FALLING WITH THIS STORM.

PEOPLE NEAR OR IN THE PATH OF THIS SEVERE STORM SHOULD FIND
SHELTER UNTIL THE STORM PASSES.

PEREZ

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 May 21, 2:57 PM MDT, 48 minutes earlier.

Area forecast discussion, May 21, 2:57 PM MDT, 48 minutes before
NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
200 PM MST WED MAY 21 1997

MORNING AVN MODEL CAPTURED THE CYCLONIC FLOW/WEAK VORT MAX OVER THE
NERN PARTS OF AZ AND MOVE IT OUT OF THE STATE DURING THE AFTERNOON.
SATELLITE IMAGERY SUPPORTS THIS IDEA.  THE AVN...HOWEVER...DIDN'T
PICK UP ON THE WEAK CIRCULATION OFF THE WEST COAST OF NRN BAJA.  NGM
DID...BUT POSITIONED IT TOO FAR EAST AS DID THE ETA MODEL.   ATTM...
NOT SURE HOW RELEVANT THIS CIRCULATION WILL BE FOR NRN AZ DURING THE
NEXT DAY OR TWO.  MAYBE TUS WILL HAVE MORE TO DEAL WITH ON THIS
MATTER.

CUMULUS DEVELOPED AROUND FLG BY 1730Z AND THE FAVORED AREAS FOR AFTN
CONVECTION LOOK TO BE THE WRN ZONES AND ALONG MOGOLLON RIM.  SFC
DEWPOINTS ARE HIGH AND THERE'S PLENTY OF MOISTURE AROUND SO AN ACTIVE
AFTERNOON IS IN THE WORKS...BUT NOT TOO CONCERNED ABOUT SVR T-STORMS.

AS FOR THE FCST...THERE'S A PRETTY COMPLICATED FLOW GOING ON OVER THE
ERN PAC AND RIDGING IS PROGGED THROUGH THE PERIOD WITH MINOR RIPPLES
EVIDENT IN THE H5 FLOW.  H7 RH HOLDS AT 60% OR GREATER...SO EXPECTING
MORE OF THE SAME WEATHER WITH SCATTERED SHOWERS ALONG THE RIM...AND
MORE ACTIVE ALONG THE ERN CWA.  WITH THE NERN CYCLONIC CIRCULATION
MOVING ON...EXPECTING TO RESUME THE DIURNAL CYCLE OF CONVECTION
THURSDAY AND FRIDAY.  WILL HOLD ON TO SCATTERED DAYTIME POPS CWA-WIDE
THROUGH THE PD...WITH HIGHEST POPS AT THE THE WHITE MTNS AND LOW
SCATTERED ELSEWHERE...WITH A GENERAL dDECREASE IN ACTIVITY AS THE
PERIOD GOES ON.  MODEL QPF'S FOLLOW THIS TREND SO IT'S A GO...

FLG 3333  INW 3322
PEREZ
FLG...NONE.

Nearby

Severe Thunderstorm Warnings in Arizona, 1997Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.