Alert archive / Arizona / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 50, NWS Flagstaff, AZ

August 11, 1997Coconino County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Aug 11, 1997, 4:38 PM MST for Coconino County, Arizona. It was in force for 37 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 11, 1997, 4:38 PM MST (23:38 UTC)
Expired: Aug 11, 1997, 5:15 PM MST
In force: 37 min
Issued by: NWS Flagstaff, AZ
Area: Whole counties

County Coconino County, AZ

The radar

The Flagstaff radar (KFSX), 150 km from the middle of the area, began a volume at 23:42 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 11, 5:15 PM MST	Hail 1	Flagstaff, AZ	One inch diameter hail reported at the Wupatki National Monument.

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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Aug 11, 12:45 PM MST	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 11.6 hours before the alert went out and 68 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: 298 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 676 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 76 m²/s²
0-3 km storm-relative helicity: 221 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.5

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 Aug 11, 2:08 PM MST, 2 hours 30 minutes earlier.

Area forecast discussion, Aug 11, 2:08 PM MST, 2 hours 30 minutes before

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
200 PM MST MON AUG 11 1997

LOW LEVEL MOISTURE PERSISTING ACROSS THE CWA THIS AFTERNOON.  JET
STREAK CONTINUING ACROSS WITH NORTHEAST AZ...PLACING IT UNDER
FAVORABLE QUAD. INGREDIENTS CAME IN PLACE FOR DEVELOPMENT OF STRONG
THUNDERSTORMS OVER THE CWA THIS AFTERNOON. FOR SHORT TERM...WATCH
STILL LOOKING GOOD AND WILL SPRINKLE ZONES WITH DECENT POPS FOR FIRST
PERIOD.

IN THE LONGER TERM...MODELS CONT TREND OF DRYING CWA OUT OVER THE
NEXT FEW DAYS.  NEED TO BE CAREFUL HERE BECAUSE MID LEVEL DRYING MAY
ACTUALLY ENHANCE DIURNAL DEVELOPMENT IF LOW LEVELS DO NOT GET SCOURED
OUT.  FOR NOW...WILL HONOR THE MODELS BY BRINGING GRADUAL DRYING
TREND...REDUCING POPS.  FOR TEMPS...NGM MOS LOOKING GOOD.
FLG 540 INW 530
FLG...NONE

In the hours before

Special weather statement, Aug 11, 2:15 PM MST, 2 hours 23 minutes before

AZZ012-112150-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
213 PM MST MON AUG 11 1997

...SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL COCONINO COUNTY
WILL EXPIRE AT 215 PM MST...

AT 213 PM MST...FLAGSTAFF DOPPLER RADAR SHOWED THAT THE
THUNDERSTORM IN EAST CENTRAL COCONINO COUNTY WAS WEAKENING
SIGNIFICANTLY. THUS THE SEVERE THUNDERSTORM WARNING FOR THAT AREA
WILL BE ALLOWED TO EXPIRE.

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 10, 10:27 PM MST	Flash Flood Warning	FGZ	Coconino	2 hr
Aug 11, 12:22 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	63 min
Aug 11, 12:33 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	52 min
Aug 11, 12:35 PM MST	Severe Thunderstorm Warning	FGZ	Navajo	55 min
Aug 11, 1:28 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	47 min
Aug 11, 1:43 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	62 min
Aug 11, 2:47 PM MST	Severe Thunderstorm Warning	FGZ	Apache	43 min
Aug 11, 3:13 PM MST	Severe Thunderstorm Warning	FGZ	Apache	32 min
Aug 11, 3:46 PM MST	Severe Thunderstorm Warning	FGZ	Apache	64 min
Aug 11, 3:56 PM MST	Flash Flood Warning	FGZ	Apache	2 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.