Alert archive / California / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 23, NWS Reno, NV

July 18, 2002Lassen County, Plumas County, Sierra County, California; Washoe County, Nevada

NWS Reno, NV issued this severe thunderstorm warning at Jul 18, 2002, 12:20 PM PDT for Lassen County, Plumas County, Sierra County, California; Washoe County, Nevada. It was in force for 25 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 18, 2002, 12:20 PM PDT (19:20 UTC)
Expired: Jul 18, 2002, 12:45 PM PDT
In force: 25 min
Issued by: NWS Reno, NV
Area: Counties, with a storm outline in the text

Counties Lassen County, CA, Plumas County, CA, Sierra County, CA, Washoe County, NV

The radar

The Reno radar (KRGX), 50 km from the middle of the area, began a volume at 19:24 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.

What was reported inside it

Time	Report	Where	Remark
Jul 18, 12:30 PM PDT	Hail 1.75	Scotts, CA	1 3/4 inch hail

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

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

Reno, NV (KREV), launched 12:00Z, 7.3 hours before the alert went out and 159 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: 5 J/kg
Mixed-layer CIN: -261 J/kg
Mixed-layer LCL: 2165 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: -1 m²/s²
0-3 km storm-relative helicity: 25 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.

740 
WUUS55 KREV 181920
SVRREV
CAC035-063-091-NVC031-182000-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE RENO NV
1219 PM PDT THU JUL 18 2002

THE NATIONAL WEATHER SERVICE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EXTREME SOUTHEASTERN LASSEN COUNTY IN NORTHERN CALIFORNIA
  SOUTHEASTERN PLUMAS COUNTY IN NORTHERN CALIFORNIA
  THIS INCLUDES THE CITY OF CHILCOOT
  NORTHEASTERN SIERRA COUNTY IN NORTHERN CALIFORNIA
  THIS INCLUDES THE CITY OF VERDI
  SOUTHWESTERN WASHOE COUNTY IN WESTERN NEVADA

* UNTIL 1245 PM PDT

* AT 1215 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS FROM 9 MILES NORTHEAST OF HALLELUJAH
  JUNCTION TO 13 MILES WEST OF DOG VALLEY...OR FROM 12 MILES
  NORTHEAST OF CHILCOOT TO 7 MILES SOUTHEAST OF SIERRAVILLE...MOVING
  NORTHWEST AT 15 MPH.

* SEVERE THUNDERSTORMS WILL BE...
  OVER DOG VALLEY AT 1240 PM PDT
  OVER VERDI...STEAD AT 1245 PM PDT

THESE STORMS WILL ALSO PRODUCE VERY HEAVY RAINFALL AND LOCAL 
FLOODING. REPORT DAMAGING WEATHER TO THE NEAREST LAW ENFORCEMENT 
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE 
FORECAST OFFICE.

LAT...LON 3991 11979 3986 12009 3969 12039 3963 12027
          3945 11995

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 Reno, NV wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 18, 9:45 AM PDT, 2 hours 35 minutes earlier.

Area forecast discussion, Jul 18, 9:45 AM PDT, 2 hours 35 minutes before

WESTERN NEVADA AND EASTERN CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
945 AM PDT THU JUL 18 2002

AIRMASS OVER WRN NV AND SIERRA REMAIN MOIST AND UNSTABLE WITH
VORT MAX NEAR SAC THIS MORNING. FORECAST LI OF -4 AND CAPE AROUND
1100 J/KG BY AFTN. K INDEX FAIRLY LOW AT 20 MAINLY DUE TO DRY AIR
AT 700 MB. SFC DEWPOINTS IN MID 40S TO LOWER 50S AND CONVECTIVE
TEMP OF 78 TRIGGERING AT 18Z. STEERING WINDS FAIRLY LIGHT BETWEEN
700 AND 500 MB LESS THAN 15 KTS. WILL ISSUE FF WATCH FOR SRN CWA
UNTIL 6 PM DUE TO SLOW MOVEMENT OF STRONG TSTMS. VORT MAX MOVES E
OF AREA FRIDAY BUT WITH RESIDUAL MOISTURE AND INSTABILITY WILL KEEP
SLGT CHC TSTMS MOST AREAS. ANOTHER VORT MAX MOVES TO CENTRAL CA CST
ON SAT FOR MORE TSTMS THIS WEEKEND. CYLKE

.REV...FLASH FLOOD WATCH NVZ01..02..03..04...CAZ073 UNTIL 6 PM.

The office that day

Everything else NWS Reno, NV issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 18, 10:50 AM PDT	Severe Thunderstorm Warning	REV	Mono	25 min
Jul 18, 12:38 PM PDT	Flash Flood Warning	REV	Lassen, Plumas	37 min
Jul 18, 12:59 PM PDT	Flash Flood Warning	REV	Nevada, Placer, Sierra	61 min
Jul 18, 1:10 PM PDT	Flash Flood Warning	REV	Lassen, Plumas, Sierra	80 min
Jul 18, 1:43 PM PDT	Flash Flood Warning	REV	El Dorado	92 min
Jul 18, 2:47 PM PDT	Flash Flood Warning	REV	Mono	58 min
Jul 18, 3:19 PM PDT	Flash Flood Warning	REV	Lassen, Nevada, Placer, Plumas, Sierra	101 min
Jul 18, 12:10 PM PDT	Severe Thunderstorm Warning	REV	Mineral	35 min
Jul 18, 3:20 PM PDT	Severe Thunderstorm Warning	REV	Pershing	25 min

Nearby

Severe Thunderstorm Warnings in California, 2002 Severe Thunderstorm Warnings in Nevada, 2002 Every 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.