Technical NOAA Weather Discussion

FXUS66 KMTR 282317
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
417 PM PDT Sat Mar 28 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1212 PM PDT Sat Mar 28 2026

 - Above normal temperatures over the weekend

 - Cooler conditions return Monday with beneficial, light rain 
   Tuesday through Thursday

&&

.SHORT TERM...
Issued at 1212 PM PDT Sat Mar 28 2026
(This evening through Sunday)

The 12Z sounding observed an 850 millibar temperature of 14.15 
degrees Celsius which is above the 90th percentile (13.5 degrees 
Celsius) for the date and time. This warm air mass will result in 
above normal temperatures that will contend with daily high 
temperature records this weekend. Stratus that was advected via a 
southerly surge is beginning to pull back to the coast where it is 
expected to stay throughout the day. The shallow marine layer of 500 
feet will likely undergo further compression as southerly flow veers 
to become northerly, promoting dry northerly flow. Stratus and 
patchy fog is expected to return to coastal locations tonight.

&&

.LONG TERM...
Issued at 1212 PM PDT Sat Mar 28 2026
(Sunday night through next Friday)

A passing upper-level shortwave trough and its associated dying cold 
front will encroach from the northwest Monday. This will crack the 
storm door open. Unfortunately, we will be far removed from the 
parent system in the Northern Great Plains; thus, only cooler 
conditions and wind are expected in the absence of rainfall. A gale 
force low pressure system in the Gulf of Alaska will head towards 
the Pacific Northwest on Tuesday. As it does so, it will pull in 
tropical moisture from the Northwestern Pacific Ocean that will 
overtop strong high pressure centered in the Northern Pacific Ocean. 
The strength of the aforementioned low will allow it to cut through 
the aforementioned high, renewing our chances for rainfall. The 
associated cold front will pass Wednesday into Thursday, bringing 
beneficial, light rainfall to the North Bay and locations along the 
bayshore and Pacific Coast. Interior higher terrain may get 
measurable rainfall with the help of orographic lift, otherwise the 
interior will remain dry. To put the month of March's precipitation 
into context we'll use San Francisco Downtown as an example. It has 
not rained there since March 2nd. If it rains on Tuesday, it'll tie 
1923 for the longest dry stretch in March. 1923 is the driest March 
on record with 0.03", 2026 is the second driest on record so far 
with 0.06". Surface high pressure will nose in from the Eastern 
Pacific Ocean on Friday, rebounding temperatures near to slightly 
above normal.

&&

.AVIATION...
(00Z TAFS)
Issued at 417 PM PDT Sat Mar 28 2026

VFR with some high clouds across the region. Gentle to moderate 
onshore winds prevail through the afternoon and evening with a weak 
offshore component persisting in the far interior regions. A shallow 
marine layer results in a moderate confidence for IFR-LIFR stratus 
overnight across the immediate coastal region, with patchy fog 
possible, especially at HAF. At STS, low probability and confidence 
for LIFR-IFR conditions early Sunday morning. Elsewhere, VFR 
conditions prevail with light winds through Sunday morning, with 
breezy onshore flow resuming in the afternoon.

Vicinity of SFO... VFR with thin high clouds through the TAF period. 
Gentle to moderate west-northwest winds continue through the evening 
hours. Winds gradually diminish in the late evening with light winds 
Sunday morning, before the breezy west-northwest winds resume during 
the afternoon. Very low probabilities of stratus impacts to the 
terminal, with the bulk of the impacts to the east closer to OAK and 
SJC. This is still a low probability forecast, and could be moot if 
the marine layer is compressed enough to prevent stratus from 
flowing through the Golden Gate.

SFO Bridge Approach... Low confidence for stratus impacts to the 
approach path, conditional on stratus making it through the 
Golden Gate. Otherwise, similar to SFO.

Monterey Bay Terminals... VFR conditions at present with gentle 
northwest winds through the evening hours. This evening, IFR-LIFR 
stratus will move into the terminal region, with the return expected 
later this evening through the early part of Sunday morning. 
However, there is low confidence on how long the ceilings will last, 
with a compressing marine layer resulting in the possibility of the 
stratus dissipating early, especially at MRY where some offshore 
flow could contribute to clearing. In any case, the stratus should 
clear by the late morning and early afternoon hours with breezy 
northwest winds resuming.

&&

.MARINE...
(Tonight through next Thursday)
Issued at 417 PM PDT Sat Mar 28 2026

Hazardous conditions for small craft continue across the northern
outer waters due to moderate to fresh northerly breezes. This
will spread into the inner waters and the rest of the outer waters
tomorrow where infrequent strong gusts are expected. Moderate
northwesterly breezes on Tuesday will back to become southerly by
Wednesday. Light rain returns Tuesday. Moderate seas will
prevail.

&&

.CLIMATE...
Issued at 717 AM PDT Sat Mar 28 2026

Here are the record high temperatures at the long term sites for
March 28th and March 29th.

Location          March 28th          March 29th

Santa Rosa        85 in 1923          86 in 2018
San Rafael        81 in 2018          85 in 2018
Kentfield         91 in 1923          84 in 1935
Napa              83 in 2015          83 in 2018, 1968
Richmond          81 in 1969          79 in 1968
Livermore         82 in 2015          85 in 2015
San Francisco     81 in 1986          81 in 2018
SFO Airport       77 in 2018          81 in 2018
Redwood City      81 in 2018          85 in 2018, 1968
Half Moon Bay     79 in 1968          77 in 2004
Oakland           79 in 2015          79 in 2003
San Jose          84 in 1923          82 in 2018
Salinas Airport   84 in 2004          86 in 2018

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM to 9 PM PDT Sunday for Pt Arena 
     to Pt Reyes 0-10 nm.

     Small Craft Advisory until 9 PM PDT Sunday for Pt Arena to Pt 
     Reyes 10-60 NM.

&&

$$

SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...DialH
MARINE...Sarment

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Prepared by Boulder-Creek.com Weather at: Sat Mar 28 20:30:02 PDT 2026
From the National Weather Service