Alert archive / California / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 21, NWS Medford, OR

August 4, 1999Siskiyou County, California

NWS Medford, OR issued this severe thunderstorm warning at Aug 4, 1999, 9:45 PM PDT for Siskiyou County, California. 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 4, 1999, 9:45 PM PDT (04:45 UTC)
Expired
Aug 4, 1999, 10:30 PM PDT
In force
45 min
Issued by
NWS Medford, OR
Area
Whole counties

County Siskiyou County, CA

The nearest sounding before it

Medford/Jackson, OR (KMFR), launched 00:00Z, 4.8 hours before the alert went out and 89 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, Medford/Jackson, OR at 00:00Z on 1999-08-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 761 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, Medford/Jackson, OR at 00:00Z on 1999-08-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 23 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
761 J/kg
Mixed-layer CIN
-79 J/kg
Mixed-layer LCL
2247 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
23 m²/s²
0-3 km storm-relative helicity
117 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KMFR 050446 RRA
SVRMFR
CAC093-050530-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MEDFORD OR
945 PM PDT WED AUG 4 1999

THE NATIONAL WEATHER SERVICE IN MEDFORD HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTH CENTRAL SISKIYOU COUNTY IN NORTH CENTRAL CALIFORNIA

* UNTIL 1030 PM PDT

* AT 945 PM...MEDFORD DOPPLER RADAR SHOWED A SEVERE THUNDERSTORM
  OVER MACDOEL MOVING NORTH ALONG HIGHWAY 97 AT 10 TO 15 MPH.

SP6OTTERS REPORTED GOLF BALL SIZE HAIL NEAR MACDOEL AT 932 PM.

THIS IS A DANGEROUS STORM! STAY INDOORS AWAY FROM WINDOWS.

MTS


&

The office that day

Everything else NWS Medford, OR issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 4, 8:33 PM PDTSevere Thunderstorm WarningMFRSiskiyou32 min
Aug 4, 9:10 PM PDTSevere Thunderstorm WarningMFRSiskiyou30 min

Nearby

Severe Thunderstorm Warnings in California, 1999Every severe thunderstorm warning in 1999

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.