FXUS66 KMTR 152105
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
205 PM PDT Sun Mar 15 2026
...New SHORT TERM, LONG TERM...
.KEY MESSAGES...
Updated at 203 PM PDT Sun Mar 15 2026
- Early season, long duration heat wave brings record-breaking
temperatures and Moderate HeatRisk through the week
- Elevated potential for grass fires through the week due to
warm and dry conditions with periods of moderate offshore winds
&&
.SHORT TERM...
Issued at 203 PM PDT Sun Mar 15 2026
(This evening through Monday)
A very shallow marine layer remains in place today and should keep
conditions near the coast cooler than areas inland. However, the
warm-up is well underway this afternoon as temperatures have warmed
into the upper 70s across the interior with maximum temperatures
forecast to be in the low to mid 80s. These temperatures are
resulting in Minor HeatRisk this afternoon and are some 10-20
degrees F above seasonal averages. 500MB heights are around 591
decameters (dam), however the ridge is placed about 380 miles west
of the region over the Pacific.
Overnight, temperatures will cool into the low to mid 50s in the
lower elevations. However, temperatures in the higher elevations
look to largely remain in the 60s. There is a low end potential for
coastal and valley fog tonight, yet will be less widespread compared
to this morning as the marine layer looks to be more compressed.
The warming trend ramps up on Monday and will continue throughout
much of the week! This is when temperatures climb to some 15-25
degrees above average across the Bay Area and Central Coast. More
widespread Moderate HeatRisk expands across the region resulting in
the issuance of a Heat Advisory for all of the region from 10 AM
Monday through 8 PM Friday. Forecast maximum high temperatures are
in the upper 70s to mid 80s near the coast with mid 80s to low 90s
across the interior.
&&
.LONG TERM...
Issued at 203 PM PDT Sun Mar 15 2026
(Monday night through next Saturday)
The high pressure will become centered overhead by Wednesday with
500MB heights approaching 595 dam over the Desert Southwest. This is
when some of the warmest, most interior areas reach the low to mid
90s while coastal areas remain in the 80s as 850MB temperatures
reach or exceed 20 degrees C. There is even the potential (30%-70%)
for Pinnacles National Park to reach 100 degrees F Wednesday through
Friday (some of the warmest days of the upcoming week).
From previous forecaster, "This is our first major heatwave of the
year and it is going to be a marathon. We are primarily expecting
Moderate HeatRisk with some relief overnight from overnight lows in
the upper 50s to low 60s. There are patches of Major HeatRisk
(impacts most people) in the higher elevations of the Santa Cruz
Mountains and interior Central Coast next week. Given the long
duration of this heat event, susceptibility to heat related
illnesses will increase throughout the week. If you are going to be
outside for prolonged periods of time make sure you are drinking
plenty of water and allowing time to rest in the shade. Never leave
people or pets unattended in the car. If possible, avoid going
outside during the peak afternoon heat (approx. 10AM - 4/5PM). Heat
Advisories will be in effect for much of the Bay Area and Central
Coast Monday through Friday with some potential to expand into next
weekend.
Expect increased potential for grass fires next week as much above
normal temperatures cure small, fine fuels (grass). Offshore winds
will remain light to moderate which will help mitigate how much any
fires that do develop can grow. If you are participating in any
outdoor activities (camping, offroading, hiking, etc) exercise
caution when using fire and be aware that the risk of grass fires
will be elevated next week."
&&
.AVIATION...
(18Z TAFS)
Issued at 1102 AM PDT Sun Mar 15 2026
High pressure will build over the region today, which
will lead to a week of fairly quiet weather. The forecast for the
next 24 hours looks to be VFR with high clouds passing over the
region, though the could be some pockets of fog if the winds go
light enough and there's enough lingering moisture MVFR to LIFR vis
is possible late tonight and/or around sunrise. Low to moderate
confidence in the exact location of fog and mist.
Vicinity of SFO...Generally VFR conditions will prevail, with onshore
winds returning by the afternoon. Winds should go to variable or
weakly offshore overnight, with onshore winds returning again
tomorrow afternoon. Uncertainty remains if SFO or terminals around
the Bay will see mist, opted to keep the TAF VFR given the lower
probabilities at this time.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Mainly offshore flow prevails this morning;
however, onshore wind is expected to return this afternoon. Winds
ease overnight and may be light and variable to less than 3KT of
offshore winds. The question for tonight will be does fog return for
the Salinas Valley and around the southern portion of the Monterey
Bay? Models are mixed, with CIGS ranging from VFR to LIFR. Opted to
go with a slightly persistence forecast, but not as pessimistic
given high pressure is building and drier air should settle in.
Moderate confidence for KMRY and KSNS TAFs.
&&
.MARINE...
(Today through Friday)
Issued at 1102 AM PDT Sun Mar 15 2026
A fresh to strong NW breeze will continue across the outer waters
before the wind speed gradually decreases to a moderate breeze
Monday and continues through mid week. Sea heights will stay
moderate due to a combination of wind waves and low southerly
swell.
&&
.CLIMATE...
Issued at 133 AM PDT Sun Mar 15 2026
The following are the record high temperatures at the long term
sites for March 15th, 16th, 17th, and 18th.
Location Mar 15 Mar 16 Mar 17 Mar 18
Santa Rosa 88 in 2004 91 in 2004 87 in 1996 84 in 2010
San Rafael 83 in 1972 87 in 1972 84 in 1972 80 in 1996
Kentfield 85 in 2004 86 in 2004 87 in 1914 89 in 1914
Napa 86 in 2004 88 in 2004 92 in 1914 87 in 1914
Richmond 85 in 2004 84 in 1972 83 in 2004 78 in 1996
Livermore 83 in 1972 88 in 1972 87 in 1972 86 in 2004
San Francisco 82 in 2004 85 in 1914 85 in 1914 86 in 1914
SFO Airport 81 in 2004 82 in 2004 82 in 2004 77 in 2004
Redwood City 84 in 2004 84 in 2004 85 in 2004 84 in 2004
Half Moon Bay 74 in 1974 78 in 1972 83 in 2004 75 in 1978
Oakland Museum 85 in 2004 85 in 2004 85 in 2004 81 in 2004
San Jose 82 in 2004 85 in 1914 88 in 1914 87 in 1914
Salinas Airport 83 in 1972 87 in 2004 87 in 2004 84 in 1960
The following are the record high temperatures at the long term
sites for the entire month of March.
Location
Santa Rosa 91 on March 16, 2004
San Rafael 88 on March 25, 1952
Kentfield 91 on March 28, 1923
Napa 92 on March 17, 1914
Richmond 87 on March 31, 2021
Livermore 90 on March 25 and 26, 2025
San Francisco 87 on March 11, 2005
SFO Airport 85 on March 25, 1952
Redwood City 89 on March 31, 2011
Half Moon Bay 83 on March 31, 2000 and March 17, 2004
Oakland Museum 88 on March 11, 2005
San Jose 89 on March 14, 2015
Salinas Airport 92 on March 14, 2015
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory from 10 AM Monday to 8 PM PDT Friday for CAZ006-
502>506-508>510-512>518-528>530.
PZ...Small Craft Advisory until 3 AM PDT Tuesday for Pt Arena to Pt
Reyes 10-60 NM.
&&
$$
SHORT TERM...RGass
LONG TERM....RGass/DialH
AVIATION...KR
MARINE...KR
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Prepared by Boulder-Creek.com Weather at: Sun Mar 15 16:30:03 PDT 2026
From the National Weather Service
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