FXUS66 KMTR 181153
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
453 AM PDT Mon May 18 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1147 PM PDT Sun May 17 2026

 - Breezy to windy conditions, especially across the North, East, and
   South Bay Mountains and the Santa Cruz Mountains through 
   Monday

 - Hazardous beach conditions through Monday

 - Hazardous marine conditions expected through Monday

 - Elevated fire weather concerns continue through Monday across
   the interior with low humidities and strong gusts

&&

.SHORT TERM...
Issued at 1147 PM PDT Sun May 17 2026
(Tonight through Monday)

An upper level low pressure system digs into the tri-state area of 
CO, UT, and WY by late Monday morning. We remain under the influence 
of the broader trough associated with it, leading to breezy offshore 
flow. North to northeast winds pick up tonight across the Santa Cruz 
Mountains, the interior North Bay Mountains, and the Eastern Santa 
Clara and East Bay Hills. Sustained wind speeds of 15 to 30 mph 
along with gusts up to 50 mph, though localized gusts up to 60 mph 
are expected for favored ridges, gaps, and passes. These winds will 
usher in drier air to the region as well, keeping the fire weather 
threat elevated for interior Bay Area and Central Coast locations. 
In terms of more every day hazards from the winds, impacts include, 
but are not limited to difficult driving, especially for high profile 
vehicles, downed tree limbs, the potential for power outages, and 
the possibility of loose or unsecured items being blown around. 

Winds begin to ease late Monday morning into the afternoon and will 
continue to decrease into the evening and overnight hours. Offshore 
winds should bring some warmer temperatures to the region, the 90s 
for the interior Bay Area valleys, the 60s to low 70s along the 
coast, and the mid 70s to low 80s for the Central Coast Valleys. 

&&

.LONG TERM...
Issued at 1147 PM PDT Sun May 17 2026
(Tuesday through next Sunday)

Upper level troughing looks to hold just west of the Desert 
Southwest and into southern CA Tuesday into Wednesday, leaving us 
with teetering between quasi-zonal and barely trough-y. Weak 
offshore lingers at least over the interior mountain ranges through 
Tuesday into Wednesday, with onshore flow trying to make a diurnally 
driven push each afternoon/evening. During this time high pressure 
just to the west of us (over the eastern Pacific) builds, pushing 
towards the coast mid week. The upper level trough begins to meander 
south to southwest of southern California late week. This should 
bring a return of onshore flow to the region and perhaps the marine 
layer. Current guidance suggests we could see a 500ft marine layer 
return by Wednesday, with a 1000-1200ft marine layer by Thursday and 
Friday. Will need to keep an eye on this as it will affect how 
temperatures pan out.

&&

.AVIATION...
(12Z TAFS)
Issued at 449 AM PDT Mon May 18 2026

Strong winds aloft continue to move through the region causing 
widespread LLWS (both in speed and directions)into the mid to late 
morning.  Gusty winds will be possible across most sites north of 
the Monterey Bay through the morning. Winds aloft decrease into the 
mid to late morning and begin to match up with moderate to breezy 
surface winds. The general wind pattern switches from northerly to 
westerly into the night, with winds becoming light into the late 
night. Haze from sea spray will continue to affect the coast.

Vicinity of SFO...VFR through the TAF period. Gusty northerly winds 
continue to affect the terminal with even stronger winds aloft, 
leading to LLWS. Winds aloft reduce slightly and align better with 
gusty surface winds in the mid morning. Gusts reduce into the mid 
afternoon and winds turn more northwest before winds turn light into 
the night.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the TAF period. Surfaces wind 
stay light through the morning with stronger winds aloft continuing 
to offer LLWS. Expect surface winds to increase and turn northwest 
into the late morning, while winds aloft reduce. Moderate northwest 
winds will ease and become light into the night, with MRY going 
southerly.

&&

.MARINE...
(Today through Saturday)
Issued at 449 AM PDT Mon May 18 2026

Winds are reducing across the marine environment, but widespread
gale- force gusts are no longer expected. Seas and winds will
still offer hazardous conditions for small craft into the mid weak
before easing for most zones. Winds will remain hazardous for
small craft into the late week for the northern outer zone.

&&

.FIRE WEATHER...
Issued at 449 AM PDT Mon May 18 2026

Strong and gusty north to northeast winds continue to affect the 
region. Expect peak gusts greater than 30 mph for most areas, 
with around 45 to 55 mph along through gaps and passes, and across
higher terrain. These winds will begin to reduce in the late
morning but remain breezy until the late night. Daytime humidity 
retentions loos to stay around 10- 25% across the interior regions
and higher peaks, with limited overnight humidity recoveries. 
Humidities will be slow to recover into the work week as a light 
offshore flow will continue to affect the district.

&&

.BEACHES...
Issued at 449 AM PDT Mon May 18 2026

A Beach Hazards Statement remains in effect for west facing 
beaches along the Pacific Coast through 9 AM due to strong winds 
over the marine environment leading to hazardously strong wind 
waves and overall rough seas. Dangerous swimming, boating, and 
surfing conditions can be expected. Large breaking waves can 
overpower swimmers resulting in significant physical injury and 
increase the risk of drowning. Gusts will stay strong along the 
immediate coast, causing blowing and drifting sand and increased 
sea spray. Water rescue attempts may be hampered by reduced 
visibilities from the sea spray. Remember, NEVER turn your back on
the ocean. 

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement until 9 AM PDT this morning for CAZ006-
     505-509-530.

     Wind Advisory until 11 AM PDT this morning for CAZ504-512-514-
     515.

     Coastal Flood Advisory until 3 AM PDT Tuesday for CAZ506.

PZ...Gale Warning until 9 AM PDT this morning for SF Bay N of Bay 
     Bridge.

     Small Craft Advisory until 9 PM PDT this evening for Mry Bay-
     Pigeon Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory until 3 AM PDT Tuesday for Pt Arena to Pt 
     Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory until 9 AM PDT this morning for Pt Pinos to 
     Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 3 AM PDT Wednesday for Pt Arena to Pt 
     Reyes 10-60 NM.

     Small Craft Advisory until 9 AM PDT Tuesday for Pigeon Pt to Pt 
     Pinos 10-60 NM.

&&

$$

SHORT TERM...KR
LONG TERM....KR
AVIATION...Murdock
MARINE...Murdock

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Prepared by Boulder-Creek.com Weather at: Mon May 18 06:30:03 PDT 2026