Alert archive / California / Special Weather Statements in 2017

Special Weather Statement, NWS Eureka, CA

August 6, 2017Siskiyou County, California

NWS Eureka, CA issued this special weather statement at Aug 6, 2017, 4:39 PM PDT for Siskiyou County, California. It was in force for 21 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 6, 2017, 4:39 PM PDT (23:39 UTC)
Expired
Aug 6, 2017, 5:00 PM PDT
In force
21 min
Issued by
NWS Eureka, CA

County Siskiyou County, CA

The radar

The Medford radar (KMAX), 97 km from the middle of the area, began a volume at 23:40 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

Medford/Jackson, OR (KMFR), launched 12:00Z, 11.7 hours before the alert went out and 130 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 12:00Z on 2017-08-06Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Medford/Jackson, OR at 12:00Z on 2017-08-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2593 m above ground
0-6 km bulk shear
4 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
54 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

380 
WWUS86 KEKA 062339
SPSEKA

Special Weather Statement
National Weather Service Eureka CA
439 PM PDT SUN AUG 6 2017

CAZ107-070000-
Northern Trinity-
439 PM PDT SUN AUG 6 2017

...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN TRINITY COUNTY...

At 437 PM PDT, a strong thunderstorm was located 12 miles southeast 
of Callahan, or 14 miles southwest of Mount Shasta, moving very 
slowly.

Winds in excess of 30 mph and half inch hail is possible with this 
storm.

This storm will remain over mainly rural areas of northeastern
Northern Trinity County.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4110 12246 4109 12251 4117 12264 4122 12270
      4127 12269 4131 12263 4133 12253 4132 12248
      4131 12250 4129 12250 4129 12251 4125 12251
      4121 12252 4118 12249 4118 12248 4116 12245
TIME...MOT...LOC 2337Z 095DEG 6KT 4124 12258 

$$

RCL

The office that day

Everything else NWS Eureka, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 6, 2:18 PM PDTSpecial Weather StatementEKATrinity12 min
Aug 6, 2:33 PM PDTSpecial Weather StatementEKATrinity12 min
Aug 6, 2:48 PM PDTSpecial Weather StatementEKA12 min
Aug 6, 2:54 PM PDTSpecial Weather StatementEKATrinity21 min
Aug 6, 2:58 PM PDTSpecial Weather StatementEKATrinity17 min
Aug 6, 3:08 PM PDTSpecial Weather StatementEKATrinity22 min
Aug 6, 3:16 PM PDTSpecial Weather StatementEKAGlenn14 min
Aug 6, 3:32 PM PDTSpecial Weather StatementEKATrinity13 min
Aug 6, 3:37 PM PDTSpecial Weather StatementEKA8 min
Aug 6, 3:49 PM PDTSpecial Weather StatementEKATrinity11 min
Aug 6, 4:04 PM PDTSpecial Weather StatementEKASiskiyou26 min
Aug 6, 4:16 PM PDTSpecial Weather StatementEKATrinity14 min
Aug 6, 4:53 PM PDTSpecial Weather StatementEKATrinity22 min
Aug 6, 4:57 PM PDTSpecial Weather StatementEKASiskiyou33 min

Nearby

Special Weather Statements in California, 2017Every special weather statement in 2017

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.