Alert archive / California / Beach Hazards Statements in 2021

Beach Hazards Statement 5, NWS San Francisco Bay Area, CA

March 8, 20216 counties in California

NWS San Francisco Bay Area, CA issued this beach hazards statement at Mar 8, 2021, 8:17 AM PST for 6 counties in California. It was in force for 13 hr.

The area

The counties it named.

The facts

Issued
Mar 8, 2021, 8:17 AM PST (16:17 UTC)
Expired
Mar 8, 2021, 9:00 PM PST
In force
13 hr
Issued by
NWS San Francisco Bay Area, CA

Counties City and County of San Francisco, CA, Marin County, CA, Monterey County, CA, San Mateo County, CA, Santa Cruz County, CA, Sonoma County, CA

The radar

The San Francisco radar (KMUX), 53 km from the middle of the area, began a volume at 16:19 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, 4.3 hours before the alert went out and 26 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 2021-03-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLLFCEL10008507005003002001001 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 2021-03-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -24 square meters per square second.1939587897117Sfc1 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
2 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
996 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
-24 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.

767 
WHUS46 KMTR 081617
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
817 AM PST Mon Mar 8 2021

...Large Shore Break possible today with arriving NW Swell...

.An arriving northwest swell train will bring the possibility of
large shore break at non-sheltered coastlines through the 
this evening. Buoys report wave heights of up to three feet 
higher than modeled and it is expected that heights will remain 
elevated through midday. Consequently, hazardous conditions will 
exist at the coast, primarily large shore break, but also somewhat
enhanced rip and long shore currents.

CAZ006-505-509-530-090300-
/O.NEW.KMTR.BH.S.0005.210308T1617Z-210309T0300Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
817 AM PST Mon Mar 8 2021

...BEACH HAZARDS STATEMENT IN EFFECT UNTIL 7 PM PST THIS
EVENING...

* WHAT...Northwest swell of 13 to 16 feet at 14 to 16 seconds.

* WHERE...San Francisco, Coastal North Bay Including Point Reyes 
  National Seashore, San Francisco Peninsula Coast and Southern 
  Monterey Bay and Big Sur Coast.

* WHEN...Until 7 PM PST this evening.

* IMPACTS... Increased risk of hazardous large breaking waves in
  shallow water along unsheltered coastlines, stronger rip and 
  longshore currents.

* ADDITIONAL DETAILS...A Beach Hazard Statement for large shore 
  break means that conditions are present to support large 
  breaking waves in shallow water. These large breaking waves can 
  lead to back and neck injuries. Swimmers should avoid swimming 
  in areas of large shore break and always swim near a lifeguard. 
  Be sure to always keep your eyes on the ocean.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
2 follow-up statements
899 
WHUS46 KMTR 090248
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
648 PM PST Mon Mar 8 2021

...Large Shore Break possible today with arriving NW Swell...

.A northwest swell train will bring the possibility of large 
shore break at non-sheltered coastlines through this evening. 
Consequently, hazardous conditions will exist at the coast, 
primarily large shore break, but also somewhat enhanced rip and 
long shore currents. Latest buoy reports are showing that wave 
heights are beginning to lower, but will keep the Beach Hazard 
Statement out for a couple more hours to ensure that hazardous 
conditions have subsided. 

CAZ006-505-509-530-090500-
/O.EXT.KMTR.BH.S.0005.000000T0000Z-210309T0500Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
648 PM PST Mon Mar 8 2021

...BEACH HAZARDS STATEMENT NOW IN EFFECT UNTIL 9 PM PST THIS
EVENING...

* WHAT...Northwest swell of 11 to 15 feet at 14 to 16 seconds.

* WHERE...San Francisco, Coastal North Bay Including Point Reyes 
  National Seashore, San Francisco Peninsula Coast and Southern 
  Monterey Bay and Big Sur Coast.

* WHEN...Until 9 PM PST this evening.

* IMPACTS... Increased risk of hazardous large breaking waves in 
  shallow water along unsheltered coastlines, stronger rip and 
  longshore currents.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
844 
WHUS46 KMTR 090446
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
846 PM PST Mon Mar 8 2021


CAZ006-505-509-530-090600-
/O.EXP.KMTR.BH.S.0005.000000T0000Z-210309T0500Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
846 PM PST Mon Mar 8 2021

...BEACH HAZARDS STATEMENT WILL EXPIRE AT 9 PM PST THIS EVENING...

Latest radar imagery shows that much of the shower activity has
diminished. There are still some moderate showers off the coast of
Big Sur and just a few showers still over the waters between Pt
Reyes and the San Francisco Peninsula. However, lightning activity
has not been detected in the past hour and the remaining showers
will be moving inland within the next hour or two. 

Another round of showers and thunderstorms are expected over the
coastal waters through the day Tuesday.

$$

Nearby

Beach Hazards Statements in California, 2021Every beach hazards statement 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.