Alert archive / Arizona / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 45, NWS Flagstaff, AZ

August 23, 1998Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Aug 23, 1998, 3:02 PM MST for Yavapai County, Arizona. It was in force for 33 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: Aug 23, 1998, 3:02 PM MST (22:02 UTC)
Expired: Aug 23, 1998, 3:35 PM MST
In force: 33 min
Issued by: NWS Flagstaff, AZ
Area: Whole counties

County Yavapai County, AZ

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 10.0 hours before the alert went out and 98 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: 121 J/kg
Mixed-layer CIN: -214 J/kg
Mixed-layer LCL: 1725 m above ground
0-6 km bulk shear: 2 kt
0-1 km storm-relative helicity: 32 m²/s²
0-3 km storm-relative helicity: 55 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 23, 2:10 PM MST, 52 minutes earlier.

Area forecast discussion, Aug 23, 2:10 PM MST, 52 minutes before

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
210 PM MST SUN AUG 23 1998

SYNOPSIS...HIGH PRESSURE WILL REMAIN OVER THE SOUTHWESTERN UNITED
STATES FOR THE NEXT FEW DAYS. LOW LEVEL MOISTURE WILL REMAIN OVER
NORTHERN ARIZONA INTO MONDAY...RESULTING IN MOSTLY SUNNY MORNINGS
WITH CLOUDS...SHOWERS AND THUNDERSTORMS DEVELOPING IN THE AFTERNOONS.

DISCUSSION...BROAD 5H RIDGE REMAINS OVER THE AREA WITH SEVERAL
FEATURES NOTED ON WV IMAGERY. FIRST...IS WEAK EASTERLY WAVE WORKING
ACROSS OLE MX...AND ANOTHER IS WEAK DEFORMATION ZONE WHICH IS ACROSS
THE SE PORTION OF THE CWA. THIS DEF ZONE NOT CONTRIBUTING MUCH TO
EARLY AFTERNOON CONVECTION...BUT IT MAY PLAY A MORE PROMINENT ROLE
LATER THIS EVENING. SFC DEW POINTS ALSO REMAINING QUITE HIGH ACROSS
THE AREA...WITH EVIDENCE OF A SURGE OCCURRING AT KYUX.

12Z MODELS INITIALIZED LARGE SCALE FLOW FAIRLY WELL. AS FAR AS
MOISTURE IS CONCERNED...AM LEANING TOWARDS THE NGM...AS IT HAS
INITIALIZED THE 700 MB FIELDS BETTER OVER THE ETA. APPEARS THAT LOW
LEVEL RH NOT GOING ANYWHERE THIS FCST PERIOD AND WILL KEEP STANDARD
MONSOON FCST. IN THE EXTENDED...TROUGH TO WORK INTO THE WESTERN US
OVER THE EXTENDED PERIOD AND FLOW TO BECOME MORE SOUTHWESTERLY.
HOWEVER...GRADIENTS STILL WEAK AND DO NOT EXPECT MUCH SCOURING TO
OCCUR THROUGH THE PERIOD. WILL KEEP CHANCE CATEGORY FOR THE EXTENDED
WITH A FEW DEGREES OF COOLING.   MCGRATH
FLG 3534 INW 2422
FLG...NONE.

In the hours before

Special weather statement, Aug 23, 9:20 AM MST, 5 hours 42 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 23, 1:46 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	34 min
Aug 23, 3:35 PM MST	Flash Flood Warning	FGZ	Coconino	90 min
Aug 23, 4:54 PM MST	Flash Flood Warning	FGZ	Coconino, Yavapai	2 hr

Nearby

Severe Thunderstorm Warnings in Arizona, 1998 Every severe thunderstorm warning in 1998

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.