Alert archive / Arizona / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 91, NWS Flagstaff, AZ

September 13, 1997Navajo County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Sep 13, 1997, 12:42 PM MDT for Navajo County, Arizona. It was in force for 43 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 13, 1997, 12:42 PM MDT (18:42 UTC)
Expired: Sep 13, 1997, 1:25 PM MDT
In force: 43 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 18:43 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, 6.7 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-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: 135 J/kg
Mixed-layer CIN: -89 J/kg
Mixed-layer LCL: 1145 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 48 m²/s²
0-3 km storm-relative helicity: 98 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 131841 RRA
SVRFLG
AZC017-131925-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1142 AM MST SAT SEP 13 1997

THE NATIONAL WEATHER SERVICE IN FLAGSTAFF AZ HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 1225 PM MST
FOR PEOPLE IN THE FOLLOWING LOCATION...

IN NORTHEASTERN ARIZONA

   ...NORTH CENTRAL NAVAJO COUNTY
 
AT 1137 AM MST...A SEVERE THUNDERSTORM WAS INDICATED BY FLAGSTAFF
DOPPLER RADAR 11 MILES NORTH NORTHWEST OF WINSLOW MOVING EAST AT 15
MPH. THS STORM WILL MOVE OVER HIGHWAYS 15 AND 87.

PEOPLE NEAR OR IN THE PATH OF THIS SEVERE STORM SHOULD FIND
SHELTER.
 
THIS IS A DANGEROUS STORM. SEVERE THUNDERSTORMS CAN AND OFTEN DO
PRODUCE TORNADOES WITH LITTLE OR NO WARNING. PLAN AHEAD AND KNOW
WHERE THE SAFEST AREAS OF YOUR HOME OR BUSINESS ARE...SUCH AS
INTERIOR ROOMS ON THE LOWEST FLOOR.

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 13, 3:32 AM MDT, 9 hours 10 minutes earlier.

Area forecast discussion, Sep 13, 3:32 AM MDT, 9 hours 10 minutes before

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
230 AM MST SAT SEP 13 1997

00Z MODELS IN FAIR AGREEMENT IN HANDLING LARGE SCALE FEATURES OVER
THE SHORT TERM. 5H RIDGE TO CONTINUE TO DOMINATE WEATHER PATTERN
THROUGH 24 HRS...AS MOIST SFC LAYER REMAINS IN PLACE OVER THE CWA.
DEWPOINT VALUES STILL RUNNING IN THE MID 50S ACROSS MOST OF THE CWA
THIS MORNING...WITH STRONG NOCTURNAL STORMS CONTINUING TO DEVELOP
OVER SOUTHERN YAVAPAI COUNTY. SHOULD SEE ANOTHER ROUND OF
THUNDERSTORM ACTIVITY AGAIN THIS  AFTERNOON. BY 18-24 HOURS SOME
DIFFERENCES BEGIN TO CREEP INTO MODEL SOLUTIONS...ESPECIALLY IN
REGARDS TO HANDLING LOW LEVEL MOISTURE WITH THE ETA-NGM. ETA PREFERS
TO KEEP MOISTURE PLUME FURTHER WEST...WHILE NGM...AS IT HAS IN THE
PAST FEW RUNS WANTS TO DRY US OUT.  A LOOK AT THE 00Z SOUNDINGS SHOW
THAT LOW LEVEL MOISTURE HAS BECOME SCOURED OUT...BUT JUST A TAD.  DO
NOT EXPECT ENOUGH MIXING TO OCCUR TODAY TO DRY US OUT TOTALLY...SO A
SCATTERING OF THUNDERSTORM DEVELOPMENT LIKELY.

FOR DAY 2 AND THE EXTENDED...ALL EYES ARE ON LINDA. EFFECTS OF LINDA
WILL LIKELY NOT BE FELT WITHIN SECOND PERIOD...NGM-ETA IN FAIR ENOUGH
AGREEMENT IN SHOWING SOME HIGH LEVEL MOISTURE FROM CLOUD SHIELD FROM
THE HURRICANE WORKING INTO THE STATE.  THIS MAY ACTUALLY HELP
SUPPRESS DIURNAL CONVECTION FOR SUNDAY. HOWEVER...A CONVECTIVE
TRIGGER MAY STILL BE AVAILABLE IN THE FORM OF WEAK DISTURBANCE
PROGGED BY ETA-NGM TO MOVE NORTHWARD OUT OF CENTRAL MX AHEAD OF
LINDA.  NGM INDICATING FEATURE MAINLY AT LOWEST LEVELS...WHILE ETA A
BIT STRONGER WITH IT. THINK THIS MAY BE MAINLY DUE TO RESOLUTION...
SINCE AVN NOT SHOWING MUCH AT ALL IN THE WAY OF DYNAMICS MOVING INTO
THE CWA. THINKING HERE IS THAT ON SUNDAY...ANY DISTURBANCE THAT DOES
MOVE ACROSS CWA WILL BE ENOUGH TO OFFSET HIGH CLOUDS FROM LINDA...SO
WILL KEEP SCATTERED POPS IN THE FORECAST FOR THE FAVORED AREAS.

LATEST NHC GUIDANCE SHOWING LITTLE CHANGE OVER PREVIOUS FORECAST.
STILL HIGHLY UNCERTAIN AS TO WHETHER SIGNIFICANT MOISTURE WILL MAKE
IT TO NORTHERN AZ BY MONDAY...SITUATION WILL NEED TO BE WATCHED
CLOSELY.
FLG 4242  INW 3232
FLG...NONE.

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 13, 2:45 AM MDT	Severe Thunderstorm Warning	FGZ	Gila, Yavapai	90 min
Sep 13, 6:31 AM MDT	Severe Thunderstorm Warning	FGZ	Coconino	64 min
Sep 13, 11:28 AM MDT	Flash Flood Warning	FGZ	Gila	117 min
Sep 13, 11:46 AM MDT	Severe Thunderstorm Warning	FGZ	Coconino	59 min
Sep 13, 5:13 PM MDT	Severe Thunderstorm Warning	FGZ	Coconino	32 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.