FXUS66 KMTR 111131
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
431 AM PDT Wed Mar 11 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 138 AM PDT Wed Mar 11 2026
- Well above normal temperatures through the forecast period
- Widespread minor HeatRisk through Saturday, areas of moderate
HeatRisk Sunday through Tuesday
&&
.SHORT TERM...
Issued at 138 AM PDT Wed Mar 11 2026
(Today through Friday)
Our region will be on the eastern periphery of upper-level shortwave
ridging across the Eastern Pacific Ocean through Thursday. As a
result, a quick warmup will ensue with temperatures around 15
degrees above normal away from the immediate coast. Fortunately the
location of the ridge will still allow for onshore flow which will
keep things comfortable at night and temperatures from running away.
The only record high in jeopardy in the short term is SJC on
Thursday with a maximum temperature forecast of 81 degrees which
would tie the record from 2007. A passing subtle upper-level
shortwave trough will tamp down the ridge and reinforce onshore
flow, pressing pause on the warming trend on Friday. 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.
&&
.LONG TERM...
Issued at 138 AM PDT Wed Mar 11 2026
(Saturday through Tuesday)
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 on Saturday. As the
aforementioned ridge encroaches our area Sunday, this will veer
winds to become northerly which will only act to further warm and
dry the region. The axis is expected to be overhead on Tuesday,
which will yield the hottest day of the forecast period. 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 Thursday of next week. To put this
into context, we will be in record breaking territory Sunday through
Tuesday. This is not just with temperatures (read the CLIMATE
section below), but monthly records for 850 mb temperatures and 500
mb heights which are both good indicators for the type of air mass
that we are dealing with. Impacts wise, widespread minor HeatRisk on
Saturday will give way to areas of moderate HeatRisk Sunday through
Tuesday. 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...
(12Z TAFS)
Issued at 431 AM PDT Wed Mar 11 2026
Mainly dry northwesterly winds continue to result in VFR. A patch
or two of stratus /LIFR-IFR/ may develop along the immediate coast
this morning, otherwise VFR is forecast.
Vicinity of SFO...VFR. West wind 5 knots increasing to 10 to 13
knots in the afternoon and early evening. West wind 5 knots tonight
becoming light and variable Thursday morning.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR. Light southeast wind through morning
then winds shifting to onshore 10 knots during the afternoon and
early evening. Light southeasterly winds redevelop tonight and
Thursday morning.
&&
.MARINE...
(Today through Monday)
Issued at 424 AM PDT Wed Mar 11 2026
Surface high pressure will continue over the coastal waters and
offshore waters through late week and the weekend. This will
result in fresh to strong northerly breezes and rough seas.
&&
.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 3 PM this afternoon to 3 AM PDT
Thursday for Pt Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory until 3 PM PDT Thursday for Pt Arena to Pt
Reyes 10-60 NM.
&&
$$
SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...Canepa
MARINE...Canepa
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Prepared by Boulder-Creek.com Weather at: Wed Mar 11 10:30:04 PDT 2026
From the National Weather Service
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