FXUS66 KMTR 121749
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1049 AM PDT Thu Mar 12 2026
...New AVIATION...
.KEY MESSAGES...
Updated at 225 AM PDT Thu Mar 12 2026
- Well above normal temperatures through the forecast period
- Widespread minor HeatRisk through Saturday, areas of moderate
HeatRisk Sunday through Wednesday
&&
.UPDATE...
Issued at 839 AM PDT Thu Mar 12 2026
Currently clear skies across the region this morning as we kick off
the start of our warming trend. Temperatures this morning are
running anywhere from 3 to 10 degrees warmer than at this time
yesterday with portions of the higher elevations up to 15 degrees
warmer. High temperatures for much of the interior will be in the
upper 70s to low 80s today with slightly cooler temps in the 60s to
70s directly along the coastline. This is the start of a potentially
long duration heat event with even warmer temperatures expected next
week. As always, when spending time outdoors make sure to listen to
your body, drink plenty of water, and allow time to rest.
&&
.SHORT TERM...
Issued at 225 AM PDT Thu Mar 12 2026
(Today through Saturday)
Temperatures around 15 degrees above normal are expected today as
the region is on the eastern periphery of upper-level shortwave
ridging across the Eastern Pacific Ocean. Fortunately the location
of the ridge will maintain onshore flow which will keep things
comfortable at night and temperatures from running away. The only
record high in jeopardy today is SJC with a maximum temperature
forecast of 81 degrees which would tie the record from 2007. A
passing upper-level shortwave trough to the north will tamp down the
ridge and reinforce onshore flow, pressing pause on the warming
trend Friday into Saturday. Of most impact in the short term will be
minor HeatRisk. To mitigate your risk: increase hydration with
water, reduce time spent outdoors or stay in the shade when the sun
is strongest, and open windows at night and use fans to bring cooler
air inside buildings. With roughly 50% of our population not having
air conditioning, it is going to be essential that all preparations
are taken to keep places of residence as temperature controlled as
possible. Examples include turning your blinds upwards and closing
them during the day, ensuring ceiling fan direction is
counterclockwise, and keeping windows open at night to take
advantage of the natural air conditioning that is onshore flow.
&&
.LONG TERM...
Issued at 225 AM PDT Thu Mar 12 2026
(Sunday through Wednesday)
Global ensemble clusters are in agreement that an anomalously high
amplitude upper-level longwave ridge will begin to move into the
region from the Eastern Pacific Ocean Sunday. As the aforementioned
ridge encroaches our area, winds will veer to become northerly which
will further warm and dry the region as the sea breeze circulation
is turned off. The axis of the ridge is expected to be overhead on
Tuesday, which will yield the hottest day of the forecast period,
before slowly drifting into the Colorado River Valley. While beyond
the official seven day forecast, there is uncertainty in the
evolution of the ridge. Even with the uncertainty, global ensemble
clusters illustrate that it is likely that we will be dealing with
anomalously high heights through Friday of next week. We will be in
record breaking territory Sunday through Wednesday not only for
daily records, but monthly records too. Forecast record breaking 850
mb temperatures and 500 mb heights are leading to a 50% probability
that SJC reaches 90 degrees - this would be the first time ever in
the month of March. It goes without saying that this is going to be
the hottest that we have been this calendar year. Impacts wise,
widespread minor HeatRisk on Saturday will give way to areas of
moderate HeatRisk Sunday through Wednesday. To mitigate your risk:
reduce time in the sun during the warmest part of the day, stay
hydrated with water, stay in a cool place during the heat of the
day, move outdoor activities to cooler times of the day, and for
those without a/c, use fans to keep air moving and open windows at
night.
&&
.AVIATION...
(18Z TAFS)
Issued at 1049 AM PDT Thu Mar 12 2026
VFR through the TAF period for all but HAF which will see moments of
low CIGs and haze into Friday morning. Mostly moderate winds build
in the mid afternoon, staying below 15 kts. Winds reduce into the
evening and night, becoming light across the region. Moderate winds
return Friday afternoon.
Vicinity of SFO...VFR through the TAF period. Moderate west winds
build in the mid afternoon, peaking around 14 kts. These winds
linger into the night before reducing as scattered low clouds
filter into the SF Bay. Winds build again into Friday afternoon.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR through the TAF period. Moderate
northwest winds build into the afternoon and last into the evening
and early night before becoming light. Winds stay variable for MRY
overnight, while SNS goes northerly into the early night, then
Northwest into Friday morning.
&&
.MARINE...
(Today through Tuesday)
Issued at 839 AM PDT Thu Mar 12 2026
Breezy to gusty northerly winds continue across the outer waters
through the weekend. Winds will eventually increase near shore
late Friday. The stronger winds will result in locally hazardous
conditions. Winds and seas ease into the next work week.
&&
.CLIMATE...
Issued at 1140 PM PDT Tue Mar 10 2026
The following are the record high temperatures at the long term
sites for March 12th, 15th, 16th and 17th.
Location Mar 12 Mar 15 Mar 16 Mar 17
Santa Rosa 83 in 2007 88 in 2004 91 in 2004 87 in 1996
San Rafael 81 in 2007 83 in 1972 87 in 1972 84 in 1972
Kentfield 83 in 2005 85 in 2004 86 in 2004 87 in 1914
Napa 86 in 2005 86 in 2004 88 in 2004 92 in 1914
Richmond 81 in 2005 85 in 2004 84 in 1972 83 in 2004
Livermore 84 in 1916 83 in 1972 88 in 1972 87 in 1972
San Francisco 79 in 2007 82 in 2004 85 in 1914 85 in 1914
SFO Airport 77 in 2007 81 in 2004 82 in 2004 82 in 2004
Redwood City 83 in 2005 84 in 2004 84 in 2004 85 in 2004
Half Moon Bay 75 in 2014 74 in 1974 78 in 1972 83 in 2004
Oakland Museum 80 in 2007 85 in 2004 85 in 2004 85 in 2004
San Jose 81 in 2007 82 in 2004 85 in 1914 88 in 1914
Salinas Airport 83 in 2007 83 in 1972 87 in 2004 87 in 2004
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 AM Friday to 3 AM PDT Saturday for
Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas
0-10 nm.
Small Craft Advisory from 3 PM Friday to 3 AM PDT Saturday for
Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory until 3 AM PDT Saturday for Pigeon Pt to Pt
Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM.
&&
$$
SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...Murdock
MARINE...Murdock
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Prepared by Boulder-Creek.com Weather at: Thu Mar 12 14:30:02 PDT 2026
From the National Weather Service
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