Alert archive / California / Beach Hazards Statements in 2019

Beach Hazards Statement 9, NWS San Francisco Bay Area, CA

December 27, 20196 counties in California

NWS San Francisco Bay Area, CA issued this beach hazards statement at Dec 27, 2019, 8:15 AM PST for 6 counties in California. It was in force for 13 hr.

The area

The counties it named.

The facts

Issued
Dec 27, 2019, 8:15 AM PST (16:15 UTC)
Expired
Dec 27, 2019, 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 16:16 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 2019-12-27Temperature 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 2019-12-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 120 square meters per square second.1939587897Sfc1 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
2101 m above ground
0-6 km bulk shear
70 kt
0-1 km storm-relative helicity
120 m²/s²
0-3 km storm-relative helicity
238 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

034 
WHUS46 KMTR 271615
CFWMTR

COASTAL HAZARD MESSAGE
National Weather Service SAN FRANCISCO CA
815 AM PST Fri Dec 27 2019

CAZ006-505-509-529-530-280500-
/O.NEW.KMTR.BH.S.0009.191227T1615Z-191228T0500Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
815 AM PST Fri Dec 27 2019

...BEACH HAZARDS STATEMENT IN EFFECT THROUGH THIS EVENING...

* HAZARDS...Increased sneaker wave risk, increased risk of rip 
  currents, large shore break.

* TIMING...Remains in effect until 9 PM Friday.

* LOCATION...Entire Pacific coastline from Sonoma south to Big 
  Sur.

* POTENTIAL IMPACTS...Larger surf at offshore breaks and an 
  enhanced risk of sneaker waves on northwest California 
  beaches. Steep beaches will have a higher risk of sneaker wave 
  activity with greater wave run-up onto beaches. Large waves 
  will also wash over jetties and rock outcroppings that may 
  normally stay dry.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Beach Hazard Statement means the potentially dangerous
conditions may exist on specific beaches. These hazards may
include large shore break...strong rip currents...and possible
sneaker waves. All of which could be life threatening.

An increased sneaker wave risk means that conditions are present
to support a heightened risk of unsuspecting beach goers being
swept into the sea by a wave. Rip currents are typically more
frequent and stronger in the vicinity of jetties...inlets...and
piers. Swimmers caught in a rip current should swim parallel to
the coast to escape the rip current before trying to swim for
shore. Swimmers should avoid swimming in areas of large shore
break and always swim near a lifeguard. Fisherman should avoid
fishing from rocks or jetties. Be sure to always keep your eyes
on the ocean.

$$

Nearby

Beach Hazards Statements in California, 2019Every beach hazards statement in 2019

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.