Alert archive / California / Special Weather Statements in 2020

Special Weather Statement, NWS Eureka, CA

August 16, 2020Mendocino County, California

NWS Eureka, CA issued this special weather statement at Aug 16, 2020, 9:21 AM PDT for Mendocino County, California. It was in force for 39 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 16, 2020, 9:21 AM PDT (16:21 UTC)
Expired
Aug 16, 2020, 10:00 AM PDT
In force
39 min
Issued by
NWS Eureka, CA

County Mendocino County, CA

The radar

The Beale AFB radar (KBBX), 117 km from the middle of the area, began a volume at 16:23 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

Oakland, CA (KOAK), launched 12:00Z, 4.4 hours before the alert went out and 237 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, Oakland, CA at 12:00Z on 2020-08-16Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 12:00Z on 2020-08-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -162 square meters per square second.193958Sfc1 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
2172 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
-162 m²/s²
0-3 km storm-relative helicity
-118 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

170 
WWUS86 KEKA 161621
SPSEKA

Special Weather Statement
National Weather Service Eureka CA
921 AM PDT Sun Aug 16 2020
 
CAZ111-161700-
Northeastern Mendocino Interior CA-
921 AM PDT Sun Aug 16 2020

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN MENDOCINO AND
NORTHERN LAKE COUNTIES UNTIL 1000 AM PDT...

At 920 AM PDT, Doppler radar was tracking a strong thunderstorm 16
miles southeast of Covelo, moving north at 25 mph.

Winds in excess of 35 to 45 mph will be possible with this storm.

This storm will remain over mainly rural and wilderness areas of 
northeastern Mendocino and northern Lake Counties around Mendocino 
National Forest.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Dangerous 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.

Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.

&&

LAT...LON 3956 12289 3960 12318 3997 12304 3997 12293
      3995 12293 3993 12291 3991 12293 3991 12295
      3984 12296 3983 12295 3979 12294 3975 12294
      3975 12291 3971 12291 3971 12289 3960 12288
TIME...MOT...LOC 1620Z 196DEG 23KT 3963 12303 

$$

AD

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 16, 4:20 AM PDTRed Flag WarningEKA8 hr
Aug 16, 6:40 AM PDTSpecial Weather StatementEKALake20 min
Aug 16, 8:16 AM PDTSpecial Weather StatementEKALake44 min
Aug 16, 9:40 AM PDTSpecial Weather StatementEKATrinity50 min
Aug 16, 12:06 PM PDTRed Flag WarningEKA16 hr

Nearby

Special Weather Statements in California, 2020Every special weather statement in 2020

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.