Alert archive / Utah / Severe Thunderstorm Watches in 2002

Severe Thunderstorm Watch 682

September 16, 200219 counties in Utah

The Storm Prediction Center issued this severe thunderstorm watch at Sep 16, 2002, 8:20 AM MDT for 19 counties in Utah. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Sep 16, 2002, 8:20 AM MDT (14:20 UTC)
Expired
Sep 16, 2002, 3:00 PM MDT
In force
7 hr
Issued by
the Storm Prediction Center

Counties Beaver County, UT, Box Elder County, UT, Cache County, UT, Davis County, UT, Garfield County, UT, Iron County, UT, Juab County, UT, Kane County, UT, Millard County, UT, Morgan County, UT, Piute County, UT, Rich County, UT, Salt Lake County, UT, Sanpete County, UT, Sevier County, UT, Tooele County, UT, Utah County, UT, Washington County, UT, Weber County, UT

Warnings issued inside it

2 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Sep 16, 11:02 AM MDTSevere Thunderstorm WarningSLCBox Elder, Davis, Tooele, Weber43 min
Sep 16, 11:42 AM MDTSevere Thunderstorm WarningSLCBox Elder, Cache, Davis, Morgan, Salt Lake, Tooele and 1 more48 min

The nearest sounding before it

Salt Lake City I, UT (KSLC), launched 12:00Z, 2.3 hours before the alert went out and 210 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, Salt Lake City I, UT at 12:00Z on 2002-09-16Temperature 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 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Salt Lake City I, UT at 12:00Z on 2002-09-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 102 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
2960 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
102 m²/s²
0-3 km storm-relative helicity
120 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.

000 
WWUS20 KWNS 161422
SEL2  
SPC WW 161420
UTZ000-162100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 682
STORM PREDICTION CENTER NORMAN OK
820 AM MDT MON SEP 16 2002

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

   WESTERN UTAH                               

EFFECTIVE THIS MONDAY MORNING AND AFTERNOON FROM 820 AM UNTIL 300
PM MDT.

HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 70 STATUTE MILES
EAST AND WEST OF A LINE FROM 45 MILES EAST OF SAINT GEORGE UTAH TO
60 MILES NORTH NORTHWEST OF OGDEN UTAH.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.  SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE
TORNADOES.

DISCUSSION...UPPER LEVEL LOW LOCATED OVER CENTRAL NV WITH 60 KT
WIND MAX WILL MOVE ENEWD ACROSS WRN UT TODAY. STRONG DYNAMICS
ASSOCIATED WITH THIS SYSTEM...PLUS A DRY BOUNDARY LAYER AND DIURNAL
HEATING SHOULD BE SUFFICIENT FOR STORMS TO PRODUCE DAMAGING WINDS. 

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 0.5 INCH EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70 KNOTS. 
A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450.  MEAN STORM MOTION
VECTOR 21050.

...IMY

415,1110 370,1113 370,1140 415,1134

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 16, 2:45 PM MDTSevere Thunderstorm WatchSPCBeaver, Carbon, Daggett, Duchesne, Emery, Piute and 6 more5 hr

Nearby

Severe Thunderstorm Watches in Utah, 2002Every severe thunderstorm watch 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.