Alert archive / Arizona / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 64, NWS Tucson, AZ

August 11, 1998Pima County, Arizona

NWS Tucson, AZ issued this severe thunderstorm warning at Aug 11, 1998, 6:30 PM MST for Pima 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
Aug 11, 1998, 6:30 PM MST (01:30 UTC)
Expired
Aug 11, 1998, 7:15 PM MST
In force
45 min
Issued by
NWS Tucson, AZ
Area
Whole counties

County Pima County, AZ

The radar

The Tucson radar (KEMX), 112 km from the middle of the area, began a volume at 01:30 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

Tuscon, AZ (KTUS), launched 00:00Z, 1.5 hours before the alert went out and 84 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, Tuscon, AZ at 00:00Z on 1998-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 736 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tuscon, AZ at 00:00Z on 1998-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -46 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
736 J/kg
Mixed-layer CIN
-14 J/kg
Mixed-layer LCL
2717 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
-46 m²/s²
0-3 km storm-relative helicity
13 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.

344 
WUUS1 KTUS 120132 RRA
SVRTUS
AZC019-120215-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TUCSON AZ
630 PM MST TUE AUG 11 1998

THE NATIONAL WEATHER SERVICE IN TUCSON HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHEASTERN PIMA COUNTY...INCLUDING NORTHWEST TUCSON AND AVRA
  VALLEY IN SOUTHERN ARIZONA

* UNTIL 715 PM MST

* AT 630 PM MST...TUCSON DOPPLER RADAR INDICATED A SEVERE
  THUNDERSTORM ACROSS THE NORTHWEST VALLEY OF TUCSON. THIS STORM
  WILL BE CAPABLE OF PRODUCING STRONG WINDS IN EXCESS OF 58 MPH
  AND VERY HEAVY RAINFALL. MOVEMENT OF THE STORM WAS NORTHWEST AT
  LESS THAN 10 MPH.

JD

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 Tucson, AZ wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 11, 2:30 PM MST, 4 hours earlier.

Area forecast discussion, Aug 11, 2:30 PM MST, 4 hours before
SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
230 PM MST TUE AUG 11 1998

SYNOPSIS...PLENTY OF MOISTURE IN SOUTHEAST ARIZONA AND THE
COMBINATION OF THIS MOISTURE AND AFTERNOON HEATING WILL RESULT IN
AFTERNOON AND EVENING THUNDERSTORMS FOR THE NEXT FEW DAYS.

DISCUSSION...STORMS ON MTNS NOW AND QUESTION IS WILL THEY MOVE OFF
OR JUST SIT THERE...BUT WITH MAX TEMP AT TUS NOW NR 100 THINK THERE
WILL BE PLENTY OF ENERGY FOR STORMS TO MOVE INTO VALLEYS. H2 WNDS
ARE NRLY AND THIS WILL BLOW ANVILS TO THE SOUTH WHICH IS USUALLY A
POSITIVE FACTOR. SINCE THIS APPEARS TO BE AN UP DAY WILL FCST A DOWN
DAY ON WED WITH STORMS DEVELOPING MAINLY NR MTNS. DONT SEE MUCH
CHANGE FOR NEXT FEW DAYS AND WILL UPSWING AGAIN THU AND FRI. TUS
6223. HOLBROOK

.TWC...FLASH FLOOD WATCH UNTIL 900 PM MST FOR ZONES 029...031>035.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 5:26 PM MSTFlash Flood WarningTWCPima64 min
Aug 11, 5:42 PM MSTSevere Thunderstorm WarningTWCPima48 min
Aug 11, 6:30 PM MSTFlash Flood WarningTWCPima60 min
Aug 11, 6:47 PM MSTSevere Thunderstorm WarningTWCPima33 min
Aug 11, 7:05 PM MSTFlash Flood WarningTWCPima60 min
Aug 11, 8:12 PM MSTFlash Flood WarningTWCPima68 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.