Alert archive / California / High Surf Warnings in 2023

High Surf Warning 1, NWS San Francisco Bay Area, CA

January 3, 20236 counties in California

NWS San Francisco Bay Area, CA issued this high surf warning at Jan 3, 2023, 8:03 PM PST for 6 counties in California. It took effect at Jan 5, 2023, 7:00 AM PST. It was in force for 26 hr. 13 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jan 3, 2023, 8:03 PM PST (04:03 UTC)
In effect from
Jan 5, 2023, 7:00 AM PST
Expired
Jan 6, 2023, 9:00 AM PST
In force
26 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 04:02 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.

What was reported inside it

TimeReportWhereRemark
Jan 5, 7:56 AM PSTFLOOD3 Ese Temelec, CACA 116 CLOSED AT CA 121 DUE TO FLOODING.
Jan 5, 9:01 AM PSTCOASTAL FLOOD4 Sse Del Monte Forest, CASEA WATER WASHING OVER HIGHWAY 1.
Jan 5, 9:52 AM PSTFLOODLagunitas-Forest Knolls, CABOULDER THE SIZE OF A LARGE DOG IN THE MIDDLE OF A ROAD.
Jan 5, 10:01 AM PSTFLOOD4 Nw Cloverdale, CAROCK SLIDE IN THE ROADWAY.
Jan 5, 11:26 AM PSTNON-TSTM WND DMG1 S Boulder Creek, CATREE AND POWER LINE DOWN ACROSS ROADWAY.
Jan 5, 11:26 AM PSTHIGH SURF7 S Del Monte Forest, CALARGE WAVES TOOK DOWN THE BACK OF A HOUSE.
Jan 5, 12:29 PM PSTFLOOD2 Ese Salinas, CALARGE AMOUNT OF WATER ACROSS THE ENTIRE ROADWAY.
Jan 5, 12:50 PM PSTFLOOD9 Se Bodega Bay, CAFLOODING ACROSS ALL LANES OF CA 1 SOUTH OF THE KEYS CREEK BRIDGE.
Jan 5, 1:41 PM PSTFLOOD1 Wnw Sausalito, CAROCKS BLOCKING THE FAR RIGHT LANE.
Jan 5, 1:53 PM PSTFLOOD5 Ne Santa Rosa, CAROCKS AND MUD IN THE ROADWAY.
Jan 5, 2:21 PM PSTFLOOD5 Nw Gonzales, CABOTH LANES OF FOLETTA RD AND ONE LANE OF BROOME RD FLOODED.
Jan 5, 2:47 PM PSTNON-TSTM WND DMG1 Nne Del Monte Forest, CAWIRES DOWN IN THE ROAD.
Jan 5, 2:51 PM PSTNON-TSTM WND DMG3 Sw Tamalpais-Homestea, CAPOWERLINES DOWN ON ROAD.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Oakland, CA (KOAK), launched 00:00Z, 4.1 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 00:00Z on 2023-01-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 00:00Z on 2023-01-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 102 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
696 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
102 m²/s²
0-3 km storm-relative helicity
165 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

006 
WHUS46 KMTR 040403
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
803 PM PST Tue Jan 3 2023

CAZ006-505-509-530-041300-
/O.NEW.KMTR.SU.W.0001.230105T1500Z-230106T1100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
803 PM PST Tue Jan 3 2023

...HIGH SURF WARNING IN EFFECT FROM 7 AM THURSDAY TO 3 AM PST
FRIDAY...

* WHAT...Dangerously large breaking waves of 20 to 27 feet
  expected.

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

* WHEN...From 7 AM Thursday to 3 AM PST Friday.

* IMPACTS...Extremely dangerous swimming and surfing conditions
  and localized beach erosion. Very arge shorebreak. Much farther
  than normal wave runup. Some beaches will be inundated at high 
  tide. Rounding or climbing over rock outcroppings will be 
  extremely dangerous. Fishing off rock walls or jetties may wash 
  you out to sea.

* ADDITIONAL DETAILS...The ocean is an unrelenting environment
  with little to no chance of rescue. Respect this force of nature
  and remain well away from hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ529-041300-
/O.NEW.KMTR.SU.Y.0001.230105T1500Z-230106T1100Z/
Northern Monterey Bay-
803 PM PST Tue Jan 3 2023

...HIGH SURF ADVISORY IN EFFECT FROM 7 AM THURSDAY TO 3 AM PST
FRIDAY...

* WHAT...Large breaking waves of 17 to 22 feet.

* WHERE...Exposed coastal areas of Northern Monterey Bay.

* WHEN...From 7 AM Thursday to 3 AM PST Friday.

* IMPACTS...Dangerous swimming and surfing conditions and
  localized beach erosion. Large shorebreak. Farther than normal
  wave runup. Some beaches will be inundated at high tide.
  Rounding or climbing over rock outcroppings will be extremely
  dangerous. Fishing off rock walls or jetties may wash you out to sea.

* ADDITIONAL DETAILS...The ocean is an unrelenting environment
  with little to no chance of rescue. Respect this force of nature
  and remain well away from hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
9 follow-up statements
444 
WHUS46 KMTR 040442
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
842 PM PST Tue Jan 3 2023

CAZ006-505-041300-
/O.NEW.KMTR.CF.Y.0001.230105T1400Z-230105T2100Z/
/O.CON.KMTR.SU.W.0001.230105T1500Z-230106T1100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
842 PM PST Tue Jan 3 2023

...COASTAL FLOOD ADVISORY IN EFFECT FROM 6 AM TO 1 PM PST
THURSDAY...
...HIGH SURF WARNING REMAINS IN EFFECT FROM 7 AM THURSDAY TO 3 AM
PST FRIDAY...

* WHAT...For the High Surf Warning, dangerously large breaking
  waves of 22 to 27 feet. For the Coastal Flood Advisory, minor
  coastal flooding expected at prone low lying coastal locations
  across the San Francisco Bay shoreline during peak high tide
  Thursday morning into early afternoon.

* WHERE...San Francisco and Coastal North Bay Including Point 
  Reyes National Seashore.

* WHEN...For the High Surf Warning, from 7 AM Thursday to 3 AM 
  PST Friday. For the Coastal Flood Advisory, from 6 AM to 1 PM 
  PST Thursday.

* IMPACTS...For the Coastal Flood Advisory: Flooding of lots, 
  parks, and roads with only isolated road closures expected. For 
  the High Surf Warning: Breaking waves can sweep people off 
  jetties and docks, and into dangerous seas. Life-threatening 
  swimming conditions and significant beach erosion can be 
  expected.

* ADDITIONAL DETAILS...For the Coastal Flood Advisory: Combination
  of high tide on Thursday plus additional 1 to 1.5 foot increase
  in water levels from storm system may result in flooding of
  areas much along the lines of what happens during King Tide
  events. For the High Surf Warning: Remain well away from 
  hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For the Coastal Flood Advisory: If travel is required, allow 
extra time as some roads may be closed. Do not drive around 
barricades or through water of unknown depth. Take the necessary 
actions to protect flood-prone property.

For the High Surf Warning: Everyone should remain out of the 
water due to life- threatening surf conditions. Stay off of 
jetties, piers, and other waterside infrastructure.

&&

$$

CAZ509-530-041300-
/O.CON.KMTR.SU.W.0001.230105T1500Z-230106T1100Z/
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
842 PM PST Tue Jan 3 2023

...HIGH SURF WARNING REMAINS IN EFFECT FROM 7 AM THURSDAY TO 3 AM
PST FRIDAY...

* WHAT...Dangerously large breaking waves of 20 to 27 feet 
  expected.

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

* WHEN...From 7 AM Thursday to 3 AM PST Friday.

* IMPACTS...Extremely dangerous swimming and surfing conditions 
  and localized beach erosion. Very large shorebreak. Much 
  farther than normal wave runup. Some beaches will be inundated 
  at high tide. Rounding or climbing over rock outcroppings will 
  be extremely dangerous. Fishing off rock walls or jetties may 
  wash you out to sea.

* ADDITIONAL DETAILS...The ocean is an unrelenting environment 
  with little to no chance of rescue. Respect this force of 
  nature and remain well away from hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ506-041300-
/O.NEW.KMTR.CF.Y.0001.230105T1400Z-230105T2100Z/
North Bay Interior Valleys-
842 PM PST Tue Jan 3 2023

...COASTAL FLOOD ADVISORY IN EFFECT FROM 6 AM TO 1 PM PST
THURSDAY...

* WHAT...Minor coastal flooding may occur.

* WHERE...Shoreline of the North Bay.

* WHEN...From 6 AM to 1 PM PST Thursday.

* IMPACTS...Possible flooding of lots, parks, and roads with only
  isolated road closures expected.

* ADDITIONAL DETAILS...Combination of high tide on Thursday plus 
  additional 1 to 1.5 foot increase in water levels from storm 
  system may result in flooding of areas much along the lines of 
  what happens during King Tide events.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If travel is required, allow extra time as some roads may be
closed. Do not drive around barricades or through water of
unknown depth. Take the necessary actions to protect flood-prone
property.

&&

$$

CAZ529-041300-
/O.CON.KMTR.SU.Y.0001.230105T1500Z-230106T1100Z/
Northern Monterey Bay-
842 PM PST Tue Jan 3 2023

...HIGH SURF ADVISORY REMAINS IN EFFECT FROM 7 AM THURSDAY TO
3 AM PST FRIDAY...

* WHAT...Large breaking waves of 17 to 22 feet.

* WHERE...Exposed coastal areas of Northern Monterey Bay.

* WHEN...From 7 AM Thursday to 3 AM PST Friday.

* IMPACTS...Dangerous swimming and surfing conditions and 
  localized beach erosion. Large shorebreak. Farther than normal 
  wave runup. Some beaches will be inundated at high tide. 
  Rounding or climbing over rock outcroppings will be extremely 
  dangerous. Fishing off rock walls or jetties may wash you out 
  to sea.

* ADDITIONAL DETAILS...The ocean is an unrelenting environment 
  with little to no chance of rescue. Respect this force of 
  nature and remain well away from hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
898 
WHUS46 KMTR 041256
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
456 AM PST Wed Jan 4 2023

CAZ006-505-042300-
/O.CON.KMTR.SU.W.0001.230105T1500Z-230106T1100Z/
/O.CON.KMTR.CF.Y.0001.230105T1400Z-230105T2100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
456 AM PST Wed Jan 4 2023

...COASTAL FLOOD ADVISORY REMAINS IN EFFECT FROM 6 AM TO 1 PM PST
THURSDAY...
...HIGH SURF WARNING REMAINS IN EFFECT FROM 7 AM THURSDAY TO 3 AM
PST FRIDAY...

* WHAT...For the High Surf Warning, dangerously large breaking
  waves of 22 to 27 feet. For the Coastal Flood Advisory, minor
  coastal flooding expected at prone low lying coastal locations
  across the San Francisco Bay shoreline during peak high tide
  Thursday morning into early afternoon.

* WHERE...San Francisco and Coastal North Bay Including Point 
  Reyes National Seashore.

* WHEN...For the High Surf Warning, from 7 AM Thursday to 3 AM 
  PST Friday. For the Coastal Flood Advisory, from 6 AM to 1 PM 
  PST Thursday.

* IMPACTS...For the Coastal Flood Advisory: Flooding of lots, 
  parks, and roads with only isolated road closures expected. For 
  the High Surf Warning: Breaking waves can sweep people off 
  jetties and docks, and into dangerous seas. Life-threatening 
  swimming conditions and significant beach erosion can be 
  expected.

* ADDITIONAL DETAILS...For the Coastal Flood Advisory: Combination
  of high tide on Thursday plus additional 1 to 1.5 foot increase
  in water levels from storm system may result in flooding of
  areas much along the lines of what happens during King Tide
  events. For the High Surf Warning: Remain well away from
  hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For the Coastal Flood Advisory: If travel is required, allow 
extra time as some roads may be closed. Do not drive around 
barricades or through water of unknown depth. Take the necessary 
actions to protect flood-prone property.

For the High Surf Warning: Everyone should remain out of the 
water due to life- threatening surf conditions. Stay off of 
jetties, piers, and other waterside infrastructure.

&&

$$

CAZ509-530-042300-
/O.CON.KMTR.SU.W.0001.230105T1500Z-230106T1100Z/
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
456 AM PST Wed Jan 4 2023

...HIGH SURF WARNING REMAINS IN EFFECT FROM 7 AM THURSDAY TO 3 AM
PST FRIDAY...

* WHAT...Dangerously large breaking waves of 20 to 27 feet
  expected.

* WHERE...San Francisco Peninsula Coast, Southern Monterey Bay 
  and the Big Sur Coast.

* WHEN...From 7 AM Thursday to 3 AM PST Friday.

* IMPACTS...Breaking waves can sweep people off jetties and 
  docks, and into dangerous seas. Life-threatening swimming 
  conditions and significant beach erosion can be expected.

* ADDITIONAL DETAILS...The ocean is an unrelenting environment 
  with little to no chance of rescue. Respect this force of 
  nature and remain well away from hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ506-042300-
/O.CON.KMTR.CF.Y.0001.230105T1400Z-230105T2100Z/
North Bay Interior Valleys-
456 AM PST Wed Jan 4 2023

...COASTAL FLOOD ADVISORY REMAINS IN EFFECT FROM 6 AM TO 1 PM PST
THURSDAY...

* WHAT...Minor coastal flooding expected.

* WHERE...North Bay Interior Valleys.

* WHEN...From 6 AM to 1 PM PST Thursday.

* IMPACTS...Possible flooding of lots, parks, and roads with only
  isolated road closures expected.

* ADDITIONAL DETAILS...Combination of high tide on Thursday plus 
  additional 1 to 1.5 foot increase in water levels from storm 
  system may result in flooding of areas much along the lines of 
  what happens during King Tide events.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If travel is required, allow extra time as some roads may be
closed. Do not drive around barricades or through water of
unknown depth. Take the necessary actions to protect flood-prone
property.

&&

$$

CAZ529-042300-
/O.CON.KMTR.SU.Y.0001.230105T1500Z-230106T1100Z/
Northern Monterey Bay-
456 AM PST Wed Jan 4 2023

...HIGH SURF ADVISORY REMAINS IN EFFECT FROM 7 AM THURSDAY TO
3 AM PST FRIDAY...

* WHAT...Large breaking waves of 17 to 22 feet.

* WHERE...Exposed coastal areas of Northern Monterey Bay.

* WHEN...From 7 AM Thursday to 3 AM PST Friday.

* IMPACTS...Dangerous swimming and surfing conditions and 
  localized beach erosion.

* ADDITIONAL DETAILS...The ocean is an unrelenting environment 
  with little to no chance of rescue. Respect this force of 
  nature and remain well away from hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Inexperienced swimmers should remain out of the water due to
dangerous surf conditions.

&&

$$
121 
WHUS46 KMTR 042145
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
145 PM PST Wed Jan 4 2023

CAZ006-505-050630-
/O.CON.KMTR.SU.W.0001.230105T1500Z-230106T1100Z/
/O.CON.KMTR.CF.Y.0001.230105T1400Z-230105T2100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
145 PM PST Wed Jan 4 2023

...COASTAL FLOOD ADVISORY REMAINS IN EFFECT FROM 6 AM TO 1 PM PST
THURSDAY...
...HIGH SURF WARNING REMAINS IN EFFECT FROM 7 AM THURSDAY TO 3 AM
PST FRIDAY...

* WHAT...For the High Surf Warning, dangerously large breaking 
  waves of 22 to 27 feet. For the Coastal Flood Advisory, minor 
  coastal flooding expected at prone low lying coastal locations 
  across the San Francisco Bay shoreline during peak high tide 
  Thursday morning into early afternoon.

* WHERE...San Francisco and Coastal North Bay Including Point 
  Reyes National Seashore.

* WHEN...For the High Surf Warning, from 7 AM Thursday to 3 AM 
  PST Friday. For the Coastal Flood Advisory, from 6 AM to 1 PM 
  PST Thursday.

* IMPACTS...For the Coastal Flood Advisory: Flooding of lots, 
  parks, and roads with only isolated road closures expected. 
  For the High Surf Warning: Breaking waves can sweep people off 
  jetties and docks, and into dangerous seas. Life-threatening 
  swimming conditions and significant beach erosion can be 
  expected.

* ADDITIONAL DETAILS...For the Coastal Flood Advisory: 
  Combination of high tide on Thursday plus additional 1 to 1.5 
  foot increase in water levels from storm system may result in 
  flooding of areas much along the lines of what happens during 
  King Tide events. For the High Surf Warning: Remain well away 
  from hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For the Coastal Flood Advisory: If travel is required, allow
extra time as some roads may be closed. Do not drive around
barricades or through water of unknown depth. Take the necessary
actions to protect flood-prone property.

For the High Surf Warning: Everyone should remain out of the
water due to life- threatening surf conditions. Stay off of
jetties, piers, and other waterside infrastructure.

&&

$$

CAZ509-530-050630-
/O.CON.KMTR.SU.W.0001.230105T1500Z-230106T1100Z/
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
145 PM PST Wed Jan 4 2023

...HIGH SURF WARNING REMAINS IN EFFECT FROM 7 AM THURSDAY TO 3 AM
PST FRIDAY...

* WHAT...Dangerously large breaking waves of 20 to 27 feet 
  expected.

* WHERE...San Francisco Peninsula Coast, Southern Monterey Bay 
  and the Big Sur Coast.

* WHEN...From 7 AM Thursday to 3 AM PST Friday.

* IMPACTS...Breaking waves can sweep people off jetties and 
  docks, and into dangerous seas. Life-threatening swimming 
  conditions and significant beach erosion can be expected.

* ADDITIONAL DETAILS...The ocean is an unrelenting environment 
  with little to no chance of rescue. Respect this force of 
  nature and remain well away from hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ506-050630-
/O.CON.KMTR.CF.Y.0001.230105T1400Z-230105T2100Z/
North Bay Interior Valleys-
145 PM PST Wed Jan 4 2023

...COASTAL FLOOD ADVISORY REMAINS IN EFFECT FROM 6 AM TO 1 PM PST
THURSDAY...

* WHAT...Minor coastal flooding expected.

* WHERE...North Bay Interior Valleys.

* WHEN...From 6 AM to 1 PM PST Thursday.

* IMPACTS...Possible flooding of lots, parks, and roads with 
  only isolated road closures expected.

* ADDITIONAL DETAILS...Combination of high tide on Thursday plus 
  additional 1 to 1.5 foot increase in water levels from storm 
  system may result in flooding of areas much along the lines of 
  what happens during King Tide events.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If travel is required, allow extra time as some roads may be
closed. Do not drive around barricades or through water of
unknown depth. Take the necessary actions to protect flood-prone
property.

&&

$$

CAZ529-050630-
/O.CON.KMTR.SU.Y.0001.230105T1500Z-230106T1100Z/
Northern Monterey Bay-
145 PM PST Wed Jan 4 2023

...HIGH SURF ADVISORY REMAINS IN EFFECT FROM 7 AM THURSDAY TO
3 AM PST FRIDAY...

* WHAT...Large breaking waves of 17 to 22 feet.

* WHERE...Exposed coastal areas of Northern Monterey Bay.

* WHEN...From 7 AM Thursday to 3 AM PST Friday.

* IMPACTS...Dangerous swimming and surfing conditions and 
  localized beach erosion.

* ADDITIONAL DETAILS...The ocean is an unrelenting environment 
  with little to no chance of rescue. Respect this force of 
  nature and remain well away from hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Inexperienced swimmers should remain out of the water due to
dangerous surf conditions.

&&

$$
747 
WHUS46 KMTR 050407
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
807 PM PST Wed Jan 4 2023

CAZ006-505-051300-
/O.CON.KMTR.SU.W.0001.230105T1500Z-230106T1100Z/
/O.CON.KMTR.CF.Y.0001.230105T1400Z-230105T2100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
807 PM PST Wed Jan 4 2023

...COASTAL FLOOD ADVISORY REMAINS IN EFFECT FROM 6 AM TO 1 PM PST
THURSDAY...
...HIGH SURF WARNING REMAINS IN EFFECT FROM 7 AM THURSDAY TO 3 AM
PST FRIDAY...

* WHAT...For the High Surf Warning, dangerously large breaking
  waves of 22 to 27 feet. For the Coastal Flood Advisory, minor 
  coastal flooding expected.

* WHERE...San Francisco and Coastal North Bay Including Point 
  Reyes National Seashore.

* WHEN...For the High Surf Warning, from 7 AM Thursday to 3 AM 
  PST Friday. For the Coastal Flood Advisory, from 6 AM to 1 PM 
  PST Thursday.

* IMPACTS...Flooding of lots, parks, and roads with only 
  isolated road closures expected. Breaking waves can sweep 
  people off jetties and docks, and into dangerous seas. Life-
  threatening swimming conditions and significant beach erosion 
  can be expected.

* ADDITIONAL DETAILS...For the Coastal Flood Advisory: 
  Combination of high tide on Thursday plus additional 1 to 1.5 
  foot increase in water levels from storm system may result in 
  flooding of areas much along the lines of what happens during 
  King Tide events. For the High Surf Warning: Remain well away 
  from hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If travel is required, allow extra time as some roads may be
closed. Do not drive around barricades or through water of
unknown depth. Take the necessary actions to protect flood-prone
property.

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ509-530-051300-
/O.CON.KMTR.SU.W.0001.230105T1500Z-230106T1100Z/
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
807 PM PST Wed Jan 4 2023

...HIGH SURF WARNING REMAINS IN EFFECT FROM 7 AM THURSDAY TO 3 AM
PST FRIDAY...

* WHAT...Dangerously large breaking waves of 20 to 27 feet.

* WHERE...San Francisco Peninsula Coast and Southern Monterey 
  Bay and Big Sur Coast.

* WHEN...From 7 AM Thursday to 3 AM PST Friday.

* IMPACTS...Breaking waves can sweep people off jetties and 
  docks, and into dangerous seas. Life-threatening swimming 
  conditions and significant beach erosion can be expected.

* ADDITIONAL DETAILS...The ocean is an unrelenting environment 
  with little to no chance of rescue. Respect this force of 
  nature and remain well away from hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ506-051300-
/O.CON.KMTR.CF.Y.0001.230105T1400Z-230105T2100Z/
North Bay Interior Valleys-
807 PM PST Wed Jan 4 2023

...COASTAL FLOOD ADVISORY REMAINS IN EFFECT FROM 6 AM TO 1 PM PST
THURSDAY...

* WHAT...Minor coastal flooding expected.

* WHERE...North Bay Interior Valleys.

* WHEN...From 6 AM to 1 PM PST Thursday.

* IMPACTS...Flooding of lots, parks, and roads with only 
  isolated road closures expected.

* ADDITIONAL DETAILS...Combination of high tide on Thursday plus 
  additional 1 to 1.5 foot increase in water levels from storm 
  system may result in flooding of areas much along the lines of 
  what happens during King Tide events.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If travel is required, allow extra time as some roads may be
closed. Do not drive around barricades or through water of
unknown depth. Take the necessary actions to protect flood-prone
property.

&&

$$

CAZ529-051300-
/O.CON.KMTR.SU.Y.0001.230105T1500Z-230106T1100Z/
Northern Monterey Bay-
807 PM PST Wed Jan 4 2023

...HIGH SURF ADVISORY REMAINS IN EFFECT FROM 7 AM THURSDAY TO
3 AM PST FRIDAY...

* WHAT...Large breaking waves of 17 to 22 feet.

* WHERE...Northern Monterey Bay.

* WHEN...From 7 AM Thursday to 3 AM PST Friday.

* IMPACTS...Dangerous swimming and surfing conditions and 
  localized beach erosion.

* ADDITIONAL DETAILS...The ocean is an unrelenting environment 
  with little to no chance of rescue. Respect this force of 
  nature and remain well away from hazardous ocean conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Inexperienced swimmers should remain out of the water due to
dangerous surf conditions.

&&

$$
814 
WHUS46 KMTR 051253
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
453 AM PST Thu Jan 5 2023

CAZ006-505-052300-
/O.CON.KMTR.SU.W.0001.230105T1500Z-230106T1100Z/
/O.CON.KMTR.CF.Y.0001.230105T1400Z-230105T2100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
453 AM PST Thu Jan 5 2023

...COASTAL FLOOD ADVISORY REMAINS IN EFFECT UNTIL 1 PM PST THIS
AFTERNOON...
...HIGH SURF WARNING REMAINS IN EFFECT UNTIL 3 AM PST FRIDAY...

* WHAT...For the High Surf Warning, dangerously large breaking
  waves of 25 to 30 feet. For the Coastal Flood Advisory, minor 
  coastal flooding expected. 

* WHERE...San Francisco and Coastal North Bay Including Point 
  Reyes National Seashore. 

* WHEN...For the High Surf Warning, from 7 AM Thursday to 3 AM 
  PST Friday. For the Coastal Flood Advisory, from 6 AM to 1 PM 
  PST Thursday. 

* IMPACTS...Flooding of lots, parks, and roads with only 
  isolated road closures expected. Breaking waves can sweep 
  people off jetties and docks, and into dangerous seas. Life- 
  threatening swimming conditions and significant beach erosion 
  can be expected. 

* ADDITIONAL DETAILS...For the Coastal Flood Advisory: 
 Combination of high tide this morning plus additional 1 to 1.5
foot increase in water levels from the storm system may result in
flooding of areas much along the lines of what happens during 
King Tide events. For the High Surf Warning: Remain well away from
hazardous ocean conditions. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If travel is required, allow extra time as some roads may be
closed. Do not drive around barricades or through water of
unknown depth. Take the necessary actions to protect flood-prone
property.

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ509-530-052300-
/O.CON.KMTR.SU.W.0001.230105T1500Z-230106T1100Z/
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
453 AM PST Thu Jan 5 2023

...HIGH SURF WARNING REMAINS IN EFFECT UNTIL 3 AM PST FRIDAY...

* WHAT...Dangerously large breaking waves of 25 to 30 feet.

* WHERE...San Francisco Peninsula Coast and Southern Monterey 
  Bay and Big Sur Coast. 

* WHEN...From 7 AM Thursday to 3 AM PST Friday.

* IMPACTS...Breaking waves can sweep people off jetties and 
  docks, and into dangerous seas. Life-threatening swimming 
  conditions and significant beach erosion can be expected. 

* ADDITIONAL DETAILS...The ocean is an unrelenting environment 
  with little to no chance of rescue. Respect this force of 
  nature and remain well away from hazardous ocean conditions. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ506-052100-
/O.CON.KMTR.CF.Y.0001.230105T1400Z-230105T2100Z/
North Bay Interior Valleys-
453 AM PST Thu Jan 5 2023

...COASTAL FLOOD ADVISORY REMAINS IN EFFECT UNTIL 1 PM PST THIS
AFTERNOON...

* WHAT...Minor coastal flooding expected.

* WHERE...North Bay Interior Valleys.

* WHEN...From 6 AM to 1 PM PST Thursday.

* IMPACTS...Flooding of lots, parks, and roads with only 
  isolated road closures expected. 

* ADDITIONAL DETAILS...Combination of high tide this morning plus
  an additional 1 to 1.5 foot increase in water levels from the storm
  system may result in flooding of areas much along the lines of 
  what happens during King Tide events. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If travel is required, allow extra time as some roads may be
closed. Do not drive around barricades or through water of
unknown depth. Take the necessary actions to protect flood-prone
property.

&&

$$

CAZ529-052300-
/O.CON.KMTR.SU.Y.0001.230105T1500Z-230106T1100Z/
Northern Monterey Bay-
453 AM PST Thu Jan 5 2023

...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 3 AM PST FRIDAY...

* WHAT...Large breaking waves of 17 to 22 feet.

* WHERE...Northern Monterey Bay.

* WHEN...From 7 AM Thursday to 3 AM PST Friday.

* IMPACTS...Dangerous swimming and surfing conditions and 
  localized beach erosion. 

* ADDITIONAL DETAILS...The ocean is an unrelenting environment 
  with little to no chance of rescue. Respect this force of 
  nature and remain well away from hazardous ocean conditions. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Inexperienced swimmers should remain out of the water due to
dangerous surf conditions.

&&

$$
458 
WHUS46 KMTR 051829
CFWMTR

URGENT - IMMEDIATE BROADCAST REQUESTED
Coastal Hazard Message
National Weather Service San Francisco CA
1029 AM PST Thu Jan 5 2023

CAZ006-505-060200-
/O.UPG.KMTR.CF.Y.0001.000000T0000Z-230105T2100Z/
/O.NEW.KMTR.CF.W.0001.230105T1829Z-230106T0000Z/
/O.CON.KMTR.SU.W.0001.000000T0000Z-230106T1100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
1029 AM PST Thu Jan 5 2023

...COASTAL FLOOD WARNING IN EFFECT UNTIL 4 PM PST THIS
AFTERNOON...
...HIGH SURF WARNING REMAINS IN EFFECT UNTIL 3 AM PST FRIDAY...

* WHAT...For the Coastal Flood Warning, coastal flooding is
  possible due to excessive rainfall runoff, high tide, and large
  westerly swell. For the High Surf Warning, dangerously large 
  breaking waves of 25 to 30 feet.

* WHERE...San Francisco and Coastal North Bay Including Point 
  Reyes National Seashore.

* WHEN...For the Coastal Flood Warning, until 4 PM PST this 
  afternoon. For the High Surf Warning, until 3 AM PST Friday.

* IMPACTS...Numerous roads may be closed. Low lying property 
  including homes, businesses, and some critical infrastructure 
  will be inundated. Some shoreline erosion will occur. Breaking 
  waves can sweep people off jetties and docks, and into 
  dangerous seas. Life-threatening swimming conditions and 
  significant beach erosion can be expected.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take the necessary actions to protect flood-prone property. If
travel is required, do not drive around barricades or through
water of unknown depth.

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ506-060000-
/O.UPG.KMTR.CF.Y.0001.000000T0000Z-230105T2100Z/
/O.NEW.KMTR.CF.W.0001.230105T1829Z-230106T0000Z/
North Bay Interior Valleys-
1029 AM PST Thu Jan 5 2023

...COASTAL FLOOD WARNING IN EFFECT UNTIL 4 PM PST THIS
AFTERNOON...

* WHAT...For the Coastal Flood Warning, coastal flooding is 
  possible due to excessive rainfall runoff, high tide, and large 
  westerly swell. 

* WHERE...North Bay Interior Valleys near the Bay Shoreline.

* WHEN...Until 4 PM PST this afternoon.

* IMPACTS...Numerous roads may be closed. Low lying property 
  including homes, businesses, and some critical infrastructure 
  will be inundated. Some shoreline erosion will occur.



PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take the necessary actions to protect flood-prone property. If
travel is required, do not drive around barricades or through
water of unknown depth.

&&

$$

CAZ509-530-060200-
/O.NEW.KMTR.CF.W.0001.230105T1829Z-230106T0000Z/
/O.CON.KMTR.SU.W.0001.000000T0000Z-230106T1100Z/
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
1029 AM PST Thu Jan 5 2023

...COASTAL FLOOD WARNING IN EFFECT UNTIL 4 PM PST THIS
AFTERNOON...
...HIGH SURF WARNING REMAINS IN EFFECT UNTIL 3 AM PST FRIDAY...

* WHAT...For the Coastal Flood Warning, coastal flooding is
  possible due to excessive rainfall runoff, high tide, and large
  westerly swell. For the High Surf Warning, dangerously large 
  breaking waves of 25 to 30 feet.

* WHERE...San Francisco Peninsula Coast and Southern Monterey 
  Bay and Big Sur Coast.

* WHEN...For the Coastal Flood Warning, until 4 PM PST this 
  afternoon. For the High Surf Warning, until 3 AM PST Friday.

* IMPACTS...Numerous roads may be closed. Low lying property 
  including homes, businesses, and some critical infrastructure 
  will be inundated. Some shoreline erosion will occur. Breaking 
  waves can sweep people off jetties and docks, and into 
  dangerous seas. Life-threatening swimming conditions and 
  significant beach erosion can be expected.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take the necessary actions to protect flood-prone property. If
travel is required, do not drive around barricades or through
water of unknown depth.

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ529-060200-
/O.NEW.KMTR.CF.W.0001.230105T1829Z-230106T0000Z/
/O.CON.KMTR.SU.Y.0001.000000T0000Z-230106T1100Z/
Northern Monterey Bay-
1029 AM PST Thu Jan 5 2023

...COASTAL FLOOD WARNING IN EFFECT UNTIL 4 PM PST THIS
AFTERNOON...
...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 3 AM PST FRIDAY...

* WHAT...For the Coastal Flood Warning, coastal flooding is
  possible due to excessive rainfall runoff, high tide, and large
  westerly swell. For the High Surf Advisory, dangerously large 
  breaking waves of 17 to 22 feet.

* WHERE...Northern Monterey Bay.

* WHEN...For the Coastal Flood Warning, until 4 PM PST this 
  afternoon. For the High Surf Advisory, until 3 AM PST Friday.

* IMPACTS...Numerous roads may be closed. Low lying property 
  including homes, businesses, and some critical infrastructure 
  will be inundated. Some shoreline erosion will occur. 
  Dangerous swimming and surfing conditions and localized beach 
  erosion.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take the necessary actions to protect flood-prone property. If
travel is required, do not drive around barricades or through
water of unknown depth.

Inexperienced swimmers should remain out of the water due to
dangerous surf conditions.

&&

$$
352 
WHUS46 KMTR 060131
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
531 PM PST Thu Jan 5 2023

CAZ006-505-509-530-061100-
/O.CON.KMTR.SU.W.0001.000000T0000Z-230106T1100Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
531 PM PST Thu Jan 5 2023

...HIGH SURF WARNING REMAINS IN EFFECT UNTIL 3 AM PST FRIDAY...

* WHAT...Dangerously large breaking waves of 25 to 30 feet.

* 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 3 AM PST Friday.

* IMPACTS...Breaking waves can sweep people off jetties and 
  docks, and into dangerous seas. Life-threatening swimming 
  conditions and significant beach erosion can be expected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ529-061100-
/O.CON.KMTR.SU.Y.0001.000000T0000Z-230106T1100Z/
Northern Monterey Bay-
531 PM PST Thu Jan 5 2023

...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 3 AM PST FRIDAY...

* WHAT...Large breaking waves of 17 to 22 feet.

* WHERE...Northern Monterey Bay.

* WHEN...Until 3 AM PST Friday.

* IMPACTS...Dangerous swimming and surfing conditions and 
  localized beach erosion.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Inexperienced swimmers should remain out of the water due to
dangerous surf conditions.

&&

$$
733 
WHUS46 KMTR 061037
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
237 AM PST Fri Jan 6 2023

CAZ006-505-509-530-061700-
/O.EXT.KMTR.SU.W.0001.000000T0000Z-230106T1700Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
237 AM PST Fri Jan 6 2023

...HIGH SURF WARNING NOW IN EFFECT UNTIL 9 AM PST THIS MORNING...

* WHAT...Dangerously large breaking waves of 22 to 27 feet.

* 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 AM PST this morning.

* IMPACTS...Breaking waves can sweep people off jetties and 
  docks, and into dangerous seas. Life-threatening swimming 
  conditions and significant beach erosion can be expected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ529-061700-
/O.EXT.KMTR.SU.Y.0001.000000T0000Z-230106T1700Z/
Northern Monterey Bay-
237 AM PST Fri Jan 6 2023

...HIGH SURF ADVISORY NOW IN EFFECT UNTIL 9 AM PST THIS MORNING...

* WHAT...Large breaking waves of 15 to 20 feet.

* WHERE...Northern Monterey Bay.

* WHEN...Until 9 AM PST this morning.

* IMPACTS...Dangerous swimming and surfing conditions and 
  localized beach erosion.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Inexperienced swimmers should remain out of the water due to
dangerous surf conditions.

&&

$$
990 
WHUS46 KMTR 061641
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
841 AM PST Fri Jan 6 2023

CAZ006-505-509-530-070500-
/O.EXP.KMTR.SU.W.0001.000000T0000Z-230106T1700Z/
/O.EXB.KMTR.SU.Y.0001.230106T1700Z-230107T0500Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
841 AM PST Fri Jan 6 2023

...HIGH SURF ADVISORY IN EFFECT UNTIL 9 PM PST THIS EVENING...
...HIGH SURF WARNING WILL EXPIRE AT 9 AM PST THIS MORNING...

* WHAT...Dangerously large breaking waves of 18 to 25 feet.

* 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...Breaking waves can sweep people off jetties and docks,
  and into dangerous seas. Dangerous swimming and surfing 
  conditions and localized beach erosion.

* ADDITIONAL DETAILS...The High Surf Warning was converted to a
  High Surf Advisory. While wave heights have trended downwards,
  buoys are still reporting dangerous waves being generated near
  the shore. Stringent caution is advised near the coastline and
  Never Turn Your Back to the Ocean!

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Inexperienced swimmers should remain out of the water due to
dangerous surf conditions.

&&

$$

CAZ529-070500-
/O.EXT.KMTR.SU.Y.0001.000000T0000Z-230107T0500Z/
Northern Monterey Bay-
841 AM PST Fri Jan 6 2023

...HIGH SURF ADVISORY NOW IN EFFECT UNTIL 9 PM PST THIS EVENING...

* WHAT...Large breaking waves of 15 to 20 feet.

* WHERE...Northern Monterey Bay.

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

* IMPACTS...Breaking waves can sweep people off jetties and docks,
  and into dangerous seas. Dangerous swimming and surfing 
  conditions and localized beach erosion.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Inexperienced swimmers should remain out of the water due to
dangerous surf conditions.

&&

$$

What forecasters said that day

The local office's own words before this high surf warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS San Francisco Bay Area, CA wrote its last area forecast discussion before this high surf warning went out at Jan 3, 4:56 PM PST, 3 hours 7 minutes earlier.

Area forecast discussion, Jan 3, 4:56 PM PST, 3 hours 7 minutes before
Area Forecast Discussion
National Weather Service San Francisco Bay Area
456 PM PST Tue Jan 3 2023

.SYNOPSIS...Cloudy but dry tonight with rain developing before
dawn Wednesday most locations. Periods of mainly light rain
Wednesday morning with increasing southerly winds. Rain may ease
for a time early Wednesday afternoon then increase in intensity
late Wednesday afternoon through the nighttime hours as a strong
cold front passes over the region. This will be when the strongest
winds and rain rates capable of producing flooding will occur.
Periods of rain continue Thursday before easing late in the day.
A relative lull in the weather Friday before yet another storm
arrives over the weekend with more storms lined up for next week.

&&

.DISCUSSION...as of 2:38 PM PST Tuesday...In general no
significant forecast changes or change in overall thinking with
the incoming system. The meteorological setup is actually quite
different than the NYE storm but at the end of the day we expect
similar type of impacts though not necessarily in the same
locations that saw them on Saturday. Will try and hash out
thoughts and details below.

Skies will remain cloudy overnight with dry conditions this
evening as the clouds keep temperatures fairly mild. Rain arrives
along the coast around 10-12z Weds as warm frontal structure of
system approaches the region. This means wet roads for the morning
commute. Initial warm advection/upslope rains on Weds should
remain in the light to moderate category, heaviest in favored
coastal hills from Sonoma to Monterey. So not expecting many
issues with the rain through midday. One difference with this
storm will be increasing southerly winds through the day. The
southeast flow will likely rain-shadow the Santa Clara and Salinas
Valleys during the day. Local 1 km WRF model is showing gusts in
the 60-80 mph range across area hills. For simplicity of messaging
and concern over saturated soils that will allow trees to more
easily topple have issued High Wind Warning for the entire
forecast area from the North Bay southward to the Central Coast.
There will be two periods of wind concern. First through the day
in the pre-frontal/warm-front environment with strong and gusty
southerly winds. Then during the evening and overnight hours when
the cold front barrels through and helps to mix down the high-
momentum air.

Strong winds are being aided by a very deep surface low forecast
to deepen to around 960 mb out near 40N/130W. During the NYE event
we had cyclogenesis spinning up a roughly 1000-1005 mb surface
low just west of the Golden Gate. (it was this cyclogenesis that
allow the AR to slow and bring heavy rain to SF and the East
Bay/Santa Cruz mtns). Thus the event is different this time in
lots of ways.

In some ways the North Bay was spared the worst if it over the
weekend and now it looks like the nose of the AR will be over the
North Bay as the cold front starts to push through late Weds
afternoon and through the overnight hours. Thus expect very heavy
rain that will likely lead to urban and small stream flooding
throughout the North Bay. Current forecasts for the Russian River
bring it to just below flood stage near Guerneville, however those
forecasts will be fine tuned every 6 hours so those with interests
along the Russian River should pay close attention to forecasts.

Cold frontal passage late Weds afternoon through the overnight
hours will be the period of most concern for heavy rain rates that
will lead to urban and small stream flooding with basins getting
overloaded. On NYE much of the heaviest rain fell during the
daylight hours while right now the current timing would make this
a nighttime event which makes it that much harder to visually
monitor activity on the rivers/streams.

Post-frontal environment on Thursday will lead to numerous showers
and even some possible thunderstorms. When all is said done still
forecasting widespread 1-3 inch rain in the lower elevations, 3-6
inches in the coastal hills with 8 inch bullseyes likely for NW
Sonoma, Mt Tam, Santa Cruz mtns and Santa Lucia range. This will
create incredible runoff over a short amount of time into the
watersheds on top of already saturated soils. We saw numerous
small landslides over the weekend and our partners at the USGS
indicate that soils have not recovered and we therefore can
expect more landslides with this event.

Next message to convey is resiliency as this will not be a "one
and done" storm. Details are still hard to pinpoint but resounding
message is several more storms look to be lined up for this
weekend, into next week and towards MLK weekend. The cumulative
effect of these storms could be quite debilitating.

At this time we expect Friday to be a relative break in the storms
day. (i.e. dry).

Next storm looks to arrive Saturday into Sunday and it does look
to have AR characteristics with high moisture plume.

Current timing would bring a break later Sunday into early Monday
with yet another moderate to strong AR possible later Monday into
Tuesday of next week followed by a brief break and another system
towards the end of next week. Of course timing and details will
change but the theme remains the same. A storm train of systems
looks to march across the Pacific and impact much of NorCal
through at least next week and possibly through MLK weekend. Its
noted that the operational gfs runs out through Jan 19th show
precip chances.

Here's a list of things to plan for and think about:

- Make sure you're signed up for your county's emergency alerts
  and/or their reverse 9-1-1 calls. Heed any evacuation orders,
  especially if you live near an area that is prone to flooding or
  mudslides.

- Have a "go bag" ready in case you need to evacuate quickly (go to
ready.gov/plan or ready.gov/kit if you're not sure what to pack).

- Find your insurance policies and other important documents. Take
  photos of rooms in your home so that you can easily reference
  items in case of damage.

- Prepare for power outages or road closures that could last
  several days. Get extra non-perishable food and have drinking
  water ready at home in case you're unable to leave home.

- Gas up your vehicles and charge up all your devices.

- Plan ahead for the elderly or others with special needs, such
  as necessary medications or other services.

- Don't forget about your pets/livestock to ensure their safety.

- Impacts can be ongoing even after the heaviest rain is over.
  Mudslides can sometimes occur several days or even weeks after
  heavy rain events. Flooded waterways may take days to recede.

- Although not as intense as what we expect on Jan 4-5, we are
  seeing a wet pattern that will continue to bring waves of
  moderate rain into the second week of January. This means soils
  could stay saturated for quite some time allowing slides, downed
  trees, and other impacts to persist.

&&

.AVIATION...As of 4:50 PM Tuesday...For the 00Z TAFs. A mix of
low and higher clouds prevails over the area this afternoon, with
VFR conditions at all of our terminals. KMUX radar data show a few
bands of residual light showers over the North Bay which look to
move to our east within the next couple of hours. Winds are light
and mostly offshore.

The first part of the approaching intense storm system will
approach during the overnight hours, with rain moving in from the
west beginning a couple of hours before sunrise Wednesday. At the
same time, winds will increase out of the southeast. MVFR to
locally IFR conditions look to generally prevail on Wednesday,
along with strong and gusty southeast winds. Winds should shift to
more out of the south following passage of the warm front around
early afternoon, with perhaps a bit of break or let-up in the
rain. But then the cold front looks to quickly move in the latter
part of the afternoon and evening, bringing potentially even
stronger winds and heavier rains.

Vicinity of SFO...VFR conditions expected to prevail through the
evening and into the overnight hours, with onset of ceilings and
rain expected during the last couple of hours before sunrise.
Winds will be light, northerly during the evening hours then
turning more offshore. Rain, with MVFR ceilings and visibilities
and increasingly strong and gusty southeasterly wind appear on tap
for Wednesday.

SFO Bridge Approach... Similar to SFO.

Monterey Bay...Alternation between VFR and MVFR ceilings and
conditions look continue in the near-term at KMRY. Otherwise, VFR
conditions look to prevail until late evening, then onset of MVFR
ceilings. MVFR ceilings and visibilities look to prevail on
Wednesday, with rain starting towards sunrise. Winds will become
increasingly strong and gusty out of the southeast, especially at
KSNS.

&&

.HYDROLOGY...This list is not all inclusive, but it highlights
some of the areas that are forecast to reach flood stage and areas
of concern for potential flooding:

***North Bay***
- Russian River at Guerneville & Geyserville
- Mark West Creek at Mirabel Heights
- Maacama Creek near Kellogg
- Laguna de Santa Rosa at Stony Point Rd near Cotati

***East Bay***
- Alameda Creek near Niles
- Alameda Creek above Div Dam near Sunol
- Arroyo de La Laguna at Verona

***South Bay***
- Potentially portions of San Francisquito Creek
- Coyote Creek above Hwy 237 at Milpitas
- Pacheco Creek near Dunneville

***Santa Cruz Mtns***
- San Lorenzo River at Big Trees
- Pajaro River at Chittenden
- Potentially Soquel Creek at Soquel

***Salinas, Carmel, Big Sur***
- Big Sur River at Big Sur
- San Antonio River near Lockwood
- Potentially Carmel River at Robles Del Rio

***San Benito County***
- Pajaro River at Chittenden

&&

.MARINE...as of 2:52 PM PST Tuesday...Showers moving through
the outer waters today as heavy seas continue through the
evening, with southerly winds starting to strengthen overnight. A
strong eastern Pacific low pressure system will swing a strong
warm front with gales across the coastal waters and bays Wednesday
with gales continuing Wednesday night. Storm force gusts possible
in the northern outer waters, gales lingering through Thursday
morning. A hazardous westerly swell builds in behind the storm
Thursday afternoon peaking at 20 to 25 feet.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
 .Tngt...Flood Watch...CAZ006-502>506-508>510-512>518-528>530
             High Wind Warning...CAZ006-502>506-508>510-512>518-528>530
             SCA...SF Bay from 3 AM
             SCA...Mry Bay from 3 AM
             SCA...Pt Arena to Pt Reyes 0-10 nm until 3 AM
             SCA...Pt Reyes to Pigeon Pt 0-10 nm until 3 AM
             SCA...Pigeon Pt to Pt Pinos 0-10 nm until 3 AM
             SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm until 3 AM
             SCA...Pt Arena to Pigeon Pt 10-60 nm until 3 AM
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 3 AM
             GLW...Pt Arena to Pt Reyes 0-10 nm from 3 AM
             GLW...Pt Reyes to Pigeon Pt 0-10 nm from 3 AM
             GLW...Pigeon Pt to Pt Pinos 0-10 nm from 3 AM
             GLW...Pt Pinos to Pt Piedras Blancas 0-10 nm from 3 AM
             GLW...Pt Arena to Pigeon Pt 10-60 nm from 3 AM
             GLW...Pigeon Pt to Pt Piedras Blancas 10-60 nm from 3 AM
&&

PUBLIC FORECAST: RW
AVIATION: Blier
MARINE: Canepa

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The office that day

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

IssuedProductOfficeCountiesLasted
Jan 3, 4:24 PM PSTRiver Flood WarningMTRSonoma34 hr
Jan 3, 8:03 PM PSTHigh Surf AdvisoryMTRMarin, Monterey, City and County of San Francisco, San Mateo, Santa Cruz, Sonoma3 days
Jan 3, 8:42 PM PSTCoastal Flood AdvisoryMTRMarin, Napa, City and County of San Francisco, Sonoma38 hr
Jan 4, 3:50 PM PSTAreal Flood AdvisoryMTRContra Costa, Marin, Napa, City and County of San Francisco, Sonoma107 min
Jan 4, 3:56 PM PSTAreal Flood AdvisoryMTRCity and County of San Francisco, San Mateo42 min

Nearby

High Surf Warnings in California, 2023Every high surf warning in 2023

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.