Alert archive / California / Special Marine Warnings in 2021

Special Marine Warning 2, NWS Eureka, CA

March 8, 2021

NWS Eureka, CA issued this special marine warning at Mar 8, 2021, 10:33 PM PST. It was in force for 27 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: Mar 8, 2021, 10:33 PM PST (06:33 UTC)
Expired: Mar 8, 2021, 11:00 PM PST
In force: 27 min
Issued by: NWS Eureka, CA
Area: Storm-based polygon
Hail: 0.75 in
Wind: 34.0 mph

The radar

The Eureka (Bunker Hill) radar (KBHX), 75 km from the middle of the area, began a volume at 06:35 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 00:00Z, 6.6 hours before the alert went out and 216 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: 20 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 1879 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 15 m²/s²
0-3 km storm-relative helicity: 106 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

607 
WHUS56 KEKA 090633
SMWEKA
PZZ470-090700-
/O.NEW.KEKA.MA.W.0002.210309T0633Z-210309T0700Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Eureka CA
1033 PM PST Mon Mar 8 2021

The National Weather Service in Eureka California has issued a

* Special Marine Warning for...
  Waters from Pt. St. George to Cape Mendocino CA from 10 to 60 nm...

* Until 1100 PM PST.

* At 1031 PM PST, a severe thunderstorm capable of producing
  waterspouts was located 30 nm west of Trinidad Head, moving
  northeast at 20 knots.

  HAZARD...Waterspouts, wind gusts 34 knots or greater, and large 
           hail.

  SOURCE...Radar.

  IMPACT...Waterspouts can easily overturn boats and create locally 
           hazardous seas. Small craft could be damaged in briefly 
           higher winds and suddenly higher waves. Large hail could 
           result in structural damage.

* The severe thunderstorm will remain over mainly open waters.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Boaters should seek safe harbor immediately until this storm passes.
Wind gusts 34 knots or greater, large hail, high waves, dangerous
lightning, and heavy rain are possible with this storm.

Thunderstorms can produce sudden waterspouts. Waterspouts can easily
overturn boats and create locally hazardous seas. Seek safe harbor
immediately.

&&

LAT...LON 4097 12469 4094 12487 4106 12494 4132 12480
      4119 12448
TIME...MOT...LOC 0631Z 208DEG 22KT 4102 12482 

WATERSPOUT...POSSIBLE
HAIL...>.75IN
WIND...>34KTS

$$

TDJ

1 follow-up statement

484 
FZUS76 KEKA 090657
MWSEKA

Marine Weather Statement
National Weather Service Eureka CA
1057 PM PST Mon Mar 8 2021

PZZ470-090706-
/O.EXP.KEKA.MA.W.0002.000000T0000Z-210309T0700Z/
1057 PM PST Mon Mar 8 2021

...THE SPECIAL MARINE WARNING WILL EXPIRE AT 1100 PM PST...

The affected areas were... 
Waters from Pt. St. George to Cape Mendocino CA from 10 to 60 nm...

The thunderstorm has weakened and no longer poses a significant
threat to boaters.

LAT...LON 4097 12469 4094 12487 4106 12494 4132 12480
      4119 12448
TIME...MOT...LOC 0656Z 208DEG 22KT 4115 12473 

$$

TDJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 8, 11:11 PM PST	Special Marine Warning	EKA		34 min
Mar 8, 11:44 PM PST	Special Marine Warning	EKA		31 min
Mar 9, 2:09 PM PST	Freeze Watch	EKA	Mendocino	24 hr
Mar 9, 2:09 PM PST	Hard Freeze Watch	EKA	Lake, Mendocino	24 hr

Nearby

Special Marine Warnings in California, 2021 Every special marine warning in 2021

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.