Alert archive / Utah / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 55, NWS Salt Lake City, UT

September 12, 2002Garfield County, Kane County, Utah

NWS Salt Lake City, UT issued this severe thunderstorm warning at Sep 12, 2002, 3:28 PM MDT for Garfield County, Kane County, Utah. It was in force for 47 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 12, 2002, 3:28 PM MDT (21:28 UTC)
Expired
Sep 12, 2002, 4:15 PM MDT
In force
47 min
Issued by
NWS Salt Lake City, UT
Area
Counties, with a storm outline in the text

Counties Garfield County, UT, Kane County, UT

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 9.5 hours before the alert went out and 260 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 2002-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 12:00Z on 2002-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 8 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1201 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
8 m²/s²
0-3 km storm-relative helicity
53 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

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 Salt Lake City, UT wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 12, 10:40 AM MDT, 4 hours 48 minutes earlier.

Area forecast discussion, Sep 12, 10:40 AM MDT, 4 hours 48 minutes before
UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1040 AM MDT THU SEP 12 2002

.SYNOPSIS...AN UPPER LOW WILL SLOWLY MOVE THROUGH THE AREA TODAY
AND INTO THE PLAINS ON FRIDAY. DEEP MOISTURE WILL REMAIN OVER THE
AREA THROUGH TONIGHT WITH DRYING FROM THE NORTHWEST ON FRIDAY.

.DISCUSSION...VERY MOIST AIRMASS OVER UTAH. UPPER LOW CIRCULATION
CENTERED JUST WEST OF PRICE PER RADAR MOSAIC.  LOW TOPPED HEAVY RAIN
PRODUCING STORMS NEAR MILFORD AND FILLMORE. ONE RAWS PICKED UP .60
IN ONE HOUR NEAR FILLMORE THIS MORNING. ISSUED A FLASH FLOOD WATCH
MOST OF SOUTHERN PORTIONS OF THE CWA AND EXTENDING NORTH TO COVER
THE RECENT BURN AREAS IN UTAH COUNTY.  NO FURTHER UPDATES PLANNED
THIS MORNING.

SLC 642 CDC 641  GIBSON

.SLC...FFASLC...FLASH FLOOD WATCH SOUTHWEST AND WEST-CENTRAL UTAH
       UNTIL 1000 PM.

The office that day

Everything else NWS Salt Lake City, UT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 12, 12:23 PM MDTTornado WarningSLCSanpete7 min
Sep 12, 1:41 PM MDTFlash Flood WarningSLCEmery, Sevier64 min
Sep 12, 2:17 PM MDTFlash Flood WarningSLCGarfield118 min
Sep 12, 2:25 PM MDTFlash Flood WarningSLCKane2 hr
Sep 12, 3:08 PM MDTFlash Flood WarningSLCEmery, Garfield, Kane, Wayne112 min
Sep 12, 4:24 PM MDTTornado WarningSLCCarbon36 min
Sep 12, 4:24 PM MDTTornado WarningSLCCarbon36 min
Sep 12, 4:50 PM MDTSevere Thunderstorm WarningSLCWashington25 min
Sep 12, 4:52 PM MDTFlash Flood WarningSLCCarbon, Emery113 min
Sep 12, 5:07 PM MDTFlash Flood WarningSLCCarbon, Emery98 min

Nearby

Severe Thunderstorm Warnings in Utah, 2002Every severe thunderstorm warning in 2002

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.