Alert archive / California / Beach Hazards Statements in 2019

Beach Hazards Statement 8, NWS San Francisco Bay Area, CA

December 24, 20196 counties in California

NWS San Francisco Bay Area, CA issued this beach hazards statement at Dec 24, 2019, 10:53 AM PST for 6 counties in California. It took effect at Dec 25, 2019, 5:00 AM PST. It was in force for 40 hr.

The area

The counties it named.

The facts

Issued
Dec 24, 2019, 10:53 AM PST (18:53 UTC)
In effect from
Dec 25, 2019, 5:00 AM PST
Expired
Dec 26, 2019, 9:00 PM PST
In force
40 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 18:56 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, 6.9 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 2019-12-24Temperature 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 2019-12-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 50 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
965 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
50 m²/s²
0-3 km storm-relative helicity
30 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

989 
WHUS46 KMTR 241853
CFWMTR

COASTAL HAZARD MESSAGE
National Weather Service SAN FRANCISCO CA
1053 AM PST Tue Dec 24 2019

...INCREASED RISK OF SNEAKER WAVES, RIP CURRENTS, AND LARGE SHORE
BREAK EARLY WEDNESDAY THROUGH THURSDAY MORNING...

.A long period northwest swell will impact the coastline from
Sonoma southward through Big Sur beginning late tonight.
Forerunners will arrive this evening, but the greatest risk of
sneaker waves impacting the coast will exist from late tonight 
through Wednesday afternoon. A sneaker wave is powerful enough to
knock unsuspecting people into the ocean. Northwest swell of 3 to
5 feet at 18 to 20 seconds is expected Wednesday morning before
building to 9 to 12 feet at 17 to 18 seconds in the afternoon and
evening. This will generate breaking waves of 17 to 22 feet at
favored locations. Swell periods will decrease throughout the day
on Thursday, but breaking waves of 15 to 20 feet will still be
possible.

CAZ006-505-509-529-530-250900-
/O.NEW.KMTR.BH.S.0008.191225T1300Z-191226T1700Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
1053 AM PST Tue Dec 24 2019

...BEACH HAZARDS STATEMENT IN EFFECT FROM LATE TONIGHT THROUGH
THURSDAY MORNING...

The National Weather Service in San Francisco has issued a Beach
Hazards Statement for increased sneaker wave risk, increased rip
current activity, and large shore break which is in effect from 
late tonight through Thursday morning.

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

* TIMING...From 5 AM Wednesday to 9 AM Thursday.

* 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.

$$
4 follow-up statements
123 
WHUS46 KMTR 250834
CFWMTR

COASTAL HAZARD MESSAGE
National Weather Service SAN FRANCISCO CA
1234 AM PST Wed Dec 25 2019

...INCREASED RISK OF SNEAKER WAVES, RIP CURRENTS, AND LARGE SHORE
BREAK EARLY WEDNESDAY THROUGH THURSDAY MORNING...

.A long period northwest swell will impact the coastline from
Sonoma southward through Big Sur beginning late tonight.
Forerunners will arrive this evening, but the greatest risk of
sneaker waves impacting the coast will exist from late tonight
through Wednesday afternoon. A sneaker wave is powerful enough to
knock unsuspecting people into the ocean. Northwest swell of 3 to
5 feet at 18 to 20 seconds is expected Wednesday morning before
building to 9 to 12 feet at 17 to 18 seconds in the afternoon and
evening. This will generate breaking waves of 17 to 22 feet at
favored locations. Swell periods will decrease throughout the day
on Thursday, but breaking waves of 15 to 20 feet will still be
possible.

CAZ006-505-509-529-530-252200-
/O.CON.KMTR.BH.S.0008.191225T1300Z-191226T1700Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
1234 AM PST Wed Dec 25 2019

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM 5 AM PST EARLY
THIS MORNING THROUGH THURSDAY MORNING...

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

* TIMING...From 5 AM Wednesday to 9 AM Thursday.

* 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.

$$
396 
WHUS46 KMTR 252147
CFWMTR

COASTAL HAZARD MESSAGE
National Weather Service SAN FRANCISCO CA
147 PM PST Wed Dec 25 2019

...INCREASED RISK OF SNEAKER WAVES, RIP CURRENTS, AND LARGE SHORE
BREAK THROUGH THURSDAY MORNING...

.A long period northwest swell will continue to impact the 
coastline from Sonoma southward through Big Sur through tomorrow
morning. The risk of sneaker waves impacting the coast remains
highest through late Wednesday afternoon. A sneaker wave is 
powerful enough to knock unsuspecting people into the ocean. 
Northwest swell of 3 to 5 feet at 18 to 20 seconds is expected 
to build to 9 to 12 feet at 17 to 18 seconds late in the 
afternoon and evening. This will generate breaking waves of 17 to 
22 feet at favored locations. Swell periods will decrease 
throughout the day on Thursday, but breaking waves of 15 to 20 
feet will still be possible.

CAZ006-505-509-529-530-261000-
/O.CON.KMTR.BH.S.0008.000000T0000Z-191226T1700Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
147 PM PST Wed Dec 25 2019

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THURSDAY
MORNING...

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

* TIMING...From 5 AM Wednesday to 9 AM Thursday.

* 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.

$$
316 
WHUS46 KMTR 260950
CFWMTR

COASTAL HAZARD MESSAGE
National Weather Service SAN FRANCISCO CA
150 AM PST Thu Dec 26 2019

...INCREASED RISK OF SNEAKER WAVES, RIP CURRENTS, AND LARGE SHORE
BREAK THROUGH THURSDAY EVENING...

.A long period northwest swell will continue to impact the
coastline from Sonoma southward through Big Sur, therefore the
Coastal Hazard has been extended through this evening. The risk 
of sneaker waves impacting the coast remains high along the 
coastline. A sneaker wave is powerful enough to knock unsuspecting
people into the ocean. The northwest swell has the ability to 
generate breaking waves of 17 to 22 feet at favored locations. 
Swell periods will decrease throughout the day on Thursday, but 
breaking waves of 15 to 20 feet will still be possible.

CAZ006-505-509-529-530-262200-
/O.EXT.KMTR.BH.S.0008.000000T0000Z-191227T0400Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
150 AM PST Thu Dec 26 2019

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

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

* TIMING...From 5 AM Wednesday to 9 PM Thursday.

* 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.

$$
150 
WHUS46 KMTR 262204
CFWMTR

COASTAL HAZARD MESSAGE
National Weather Service SAN FRANCISCO CA
204 PM PST Thu Dec 26 2019

...INCREASED RISK OF SNEAKER WAVES, RIP CURRENTS, AND LARGE SHORE
BREAK THROUGH THURSDAY EVENING...

.A long period northwest swell will continue to impact the
coastline from Sonoma southward through Big Sur, therefore the
Coastal Hazard remains in effect through this evening. The risk 
of sneaker waves impacting the coast remains elevated along the 
coastline. A sneaker wave is powerful enough to knock unsuspecting
people into the ocean. The northwest swell has the ability to 
generate breaking waves of 15 to 20 feet at favored locations. 
Swell periods heights and periods will subside overnight.

CAZ006-505-509-529-530-270500-
/O.EXT.KMTR.BH.S.0008.000000T0000Z-191227T0500Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-Northern Monterey Bay-
Southern Monterey Bay and Big Sur Coast-
204 PM PST Thu Dec 26 2019

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

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

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

* 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.

$$

The office that day

Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 24, 2:03 PM PSTSmall Craft AdvisoryMTR4 days

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.