Alert archive / California / Special Marine Warnings in 2021

Special Marine Warning 4, NWS Eureka, CA

March 8, 2021

NWS Eureka, CA issued this special marine warning at Mar 8, 2021, 11:44 PM PST. It was in force for 31 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, 11:44 PM PST (07:44 UTC)
Expired
Mar 9, 2021, 12:15 AM PST
In force
31 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), 22 km from the middle of the area, began a volume at 07:42 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, 7.7 hours before the alert went out and 235 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 2021-03-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 20 joules per kilogram.LCLEL10008507005003002001001 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 00:00Z on 2021-03-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 square meters per square second.19395878Sfc1 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
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.

424 
WHUS56 KEKA 090744
SMWEKA
PZZ450-470-090815-
/O.NEW.KEKA.MA.W.0004.210309T0744Z-210309T0815Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Eureka CA
1144 PM PST Mon Mar 8 2021

The National Weather Service in Eureka California has issued a

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

* Until 1215 AM PST.

* At 1144 PM PST, a severe thunderstorm capable of producing
  waterspouts was located 10 nm northwest of Cape Mendocino, moving
  northeast at 20 knots.

  HAZARD...Waterspouts, wind gusts 34 knots or greater, and small 
           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.

* The severe thunderstorm will remain over mainly open waters.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Report severe weather to the Coast Guard or the National Weather
Service.

&&

LAT...LON 4053 12451 4062 12465 4086 12437 4074 12425
TIME...MOT...LOC 0744Z 229DEG 18KT 4061 12451 

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

$$

CB
1 follow-up statement
491 
FZUS76 KEKA 090812
MWSEKA

Marine Weather Statement
National Weather Service Eureka CA
1212 AM PST Tue Mar 9 2021

PZZ450-470-090819-
/O.EXP.KEKA.MA.W.0004.000000T0000Z-210309T0815Z/
1212 AM PST Tue Mar 9 2021

...THE SPECIAL MARINE WARNING WILL EXPIRE AT 1215 AM PST...

The affected areas were... 
Coastal waters from Pt. St. George to Cape Mendocino CA out 10 nm...
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 4053 12451 4062 12465 4086 12437 4074 12425
TIME...MOT...LOC 0809Z 229DEG 18KT 4064 12446 

$$

CB

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 8, 10:33 PM PSTSpecial Marine WarningEKA27 min
Mar 8, 11:11 PM PSTSpecial Marine WarningEKA34 min
Mar 9, 2:09 PM PSTFreeze WatchEKAMendocino24 hr
Mar 9, 2:09 PM PSTHard Freeze WatchEKALake, Mendocino24 hr

Nearby

Special Marine Warnings in California, 2021Every 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.