Alert archive / Arizona / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 39, NWS Flagstaff, AZ

August 12, 1998Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Aug 12, 1998, 3:50 PM MST for Yavapai County, Arizona. It was in force for 50 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 12, 1998, 3:50 PM MST (22:50 UTC)
Expired
Aug 12, 1998, 4:40 PM MST
In force
50 min
Issued by
NWS Flagstaff, AZ
Area
Whole counties

County Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 124 km from the middle of the area, began a volume at 22:53 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, 10.8 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-pSkew-T log-p diagram, Flgstf/Belemont, AZ at 12:00Z on 1998-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 23 joules per kilogram.LCLLFCEL10008507005003002001001 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 1998-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 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
23 J/kg
Mixed-layer CIN
-112 J/kg
Mixed-layer LCL
1797 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
9 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.

406 
WUUS1 KFLG 122255 RRA
SVRFLG
AZC025-122340-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
350 PM MST WED AUG 12 1998

THE NATIONAL WEATHER SERVICE IN FLAGSTAFF HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN YAVAPAI COUNTY IN CENTRAL ARIZONA

* UNTIL 440 PM MST

* AT 348 PM MST...  NATIONAL WEATHER SERVICE DOPPLER RADAR
  INDICATED A SEVERE THUNDERSTORM 21 MILES SOUTHWEST OF PAYSON OR
  21 MILES SOUTH OF CHILDS MOVING SOUTHWEST AT 15 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  HORSESHOE LAKE AT AROUND 400 PM.

IF YOU ARE IN THE WARNING AREA... SEEK SAFETY IN AN INTERIOR ROOM
AWAY FROM WINDOWS. IF YOU ARE CAUGHT OUTSIDE... TRY TO FIND
SHELTER IN A WELL PROTECTED AREA. SEVERE THUNDERSTORMS PRODUCE
DAMAGING WIND AND HAIL ALONG WITH VERY HEAVY RAIN AND FREQUENT
LIGHTNING.

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 12, 2:00 PM MST, 1 hour 50 minutes earlier.

Area forecast discussion, Aug 12, 2:00 PM MST, 1 hour 50 minutes before
NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
200 PM MST WED AUG 12 1998

SYNOPSIS...A UPPER LEVEL HIGH PRESSURE CENTER OVER NEVADA WILL SLOWLY
SHIFT SOUTHEAST THE NEXT COUPLE DAYS. MONSOON MOISTURE IS EXPECTED TO
REMAIN IN PLACE ACROSS NORTHERN ARIZONA FOR CONTINUED DAYTIME
THUNDERSTORM DEVELOPMENT.

DISCUSSION...LESS THUNDERSTORM ACTIVITY TODAY DUE TO RELATIVELY COOL
SURFACE CONDITIONS FROM CLOUDINESS EARLIER. 500MB FLOW IS A BIT MORE
COHERENT TODAY WITH HIGH CENTER OVER NEVADA PRODUCING NORTHEAST
STEERING WINDS FOR THE THUNDERSTORM MOVEMENT. CHECK OF 12Z MODELS
SHOWS USUAL MUDDLED INITIALIZATION OF ATMOSPHERIC MOISTURE. NGM/ETA
DO INDICATE AN INCREASE IN MID LEVEL RH AS FLOW BECOMES EASTERLY TO
SOUTHEASTERLY AS HIGH SHIFTS TO THE SOUTHEAST. BIT OF DISCREPANCY IN
THE MODELS WHERE HIGH CENTER WILL END UP BY THIS WEEKEND. BUT
REGARDLESS...MOISTURE ISN'T GOING ANYWHERE...SO WILL CONTINUE LOW TO
MEDIUM GRA`DE MONSOON FORECAST. FLG252 INW232 ...SIGLER

FLG...NONE.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 2:15 PM MSTSevere Thunderstorm WarningFGZGila50 min

Nearby

Severe Thunderstorm Warnings in Arizona, 1998Every 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; radar from the NEXRAD Level II archive.