FXUS66 KMTR 032043
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
143 PM PDT Fri Apr 3 2026

...New CLIMATE...

.KEY MESSAGES...
Updated at 107 PM PDT Fri Apr 3 2026

 - Moderate to strong offshore flow through remainder of today

 - Warmer temperatures return Saturday and Sunday before a cooling
   trend begins next week

 - Beneficial rain chances increase mid to late next week

&&

.SHORT TERM...
Issued at 107 PM PDT Fri Apr 3 2026
(This evening through Saturday)

Breezy offshore winds continue through early tomorrow morning. The 
strongest wind gusts have largely been confined to the higher 
elevations of the North Bay Interior Mountains and the Diablo Range. 
The strongest gust reported so far was 67 mph at the Mt. St. Helena 
West Station (elevation of 4340 ft) at 7:30 AM this morning. At that 
time the SFO-WMC pressure gradient peaked at -10 mb. Winds have 
since come down slightly but are likely to increase again during the 
afternoon and evening hours. The SFO-WMC gradient has regained 
strengthen over the last few hours (after initially weakening from 
early this morning) with the 11AM observation coming in at -9.80 mb. 
GFS guidance most closely resembles the observed SFO-WMC gradient 
and keeps offshore winds continuing into Sunday. Another, brief, 
round of breezy winds is possible across the higher elevations early 
Saturday morning before winds decrease through the remainder of the 
day.

High temperatures today are seasonably warm in the 60s along the 
coast and 70s across the interior. This is running about 5 to 10 
degrees above normal for this time of year and is the result of 
upper level ridging and surface high pressure building in. The 
warming trend continues into Saturday with high temperatures in the 
70s to 80s expected (15-20 degrees above normal). Currently only 
Minor HeatRisk is forecast today and tomorrow thanks to good 
overnight cooling. Light, offshore winds prevail on Saturday which 
will play a role in keeping coastal areas warmer thanks to an effect 
called downsloping. Downsloping occurs when wind is forced down the 
leeward side of the mountain with an air parcel compressing (and 
warming) as it sinks. This type of setup is favorable for bringing 
much warmer and drier temperatures directly along the coast compared 
to the normally cooler temperatures we observe. For the afternoon 
forecast package, did adjust high temperatures up slightly for 
Saturday and Sunday given that the deterministic NBM was running 
much cooler than other models. Given the very dry atmosphere, fog is 
not expected to develop tonight with HREF only showing high clouds 
moving through. 

&&

.LONG TERM...
Issued at 107 PM PDT Fri Apr 3 2026
(Saturday night through next Thursday)

Above normal temperatures continue into Sunday with highs remaining 
15-20 degrees above normal. This keeps temperatures in the 80s 
across the interior and 70s along the coastline. There is a little 
more uncertainty with regards to Sunday's high temperatures than 
Saturday's. On Saturday, the center of the upper level ridge is 
centered more over California while on Sunday the ridge is 
progressing rapidly eastward. As the ridge departs, the SFO-WMC 
pressure gradient is expected to reverse (becoming positive) and 
onshore flow returns. Currently, offshore winds are likely to remain 
through at least Sunday morning but potentially into early Sunday 
afternoon. The longer offshore winds stick around, the more surface 
temperatures are able to warm. The current thinking is that 
temperatures will peak early to mid afternoon and start decreasing 
as the sea breeze/onshore winds kick in. Another factor is the 
potential for the marine layer to redevelop, bringing a return of 
coastal stratus and fog. The marine layer now looks to return 
overnight Sunday into Monday than Sunday afternoon/evening. This 
limits the impact it would have on Sunday's high temperatures but 
it's worthwhile noting that the signal is there for the marine layer 
to redevelop heading into next week. There is the potential for some 
daily high temperature records to be broken Saturday and Sunday (one 
site being Half Moon Bay) depending on how high temperatures warm.

Temperatures cool slightly, becoming seasonably warm, into the 70s 
to low 80s across the interior Monday and Tuesday as upper level 
ridging progresses eastward and zonal flow returns. The coast will 
be noticeably cooler with seasonal high temperatures in the 60s 
expected. The cooling trend continues through late next week as an 
upper level trough moves through the West Coast. This system will 
bring us our next chance of beneficial rain. Totals are still light 
with the majority of the region seeing less than a quarter of an 
inch. The higher elevations of the Santa Cruz Mountains and the 
Santa Lucia Range may see between 0.25 to 0.5" of rain. There is 
also the potential for this system to bring locally gustier onshore 

&&

.AVIATION...
(18Z TAFS)
Issued at 1104 AM PDT Fri Apr 3 2026

Dry air and offshore winds support VFR for the 18z TAFs. 

Vicinity of SFO...VFR. Northeast wind near 5 knots becoming 
northwest 10 to 15 knots in the afternoon and early evening. Wind
shifting to light southeast tonight and continuing Saturday 
before shifting to northwest near 10 knots late Saturday 
afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR. East to southeast winds 5 to 15 
knots shifting to northwesterly 10 knots in the afternoon and 
early evening. Winds shifting to east to southeast 5 to 15 knots
tonight and Saturday morning.

&&

.MARINE...
(Today through Wednesday)
Issued at 1052 AM PDT Fri Apr 3 2026

Fresh to strong northerly breezes will persist over the northern
outer waters through today. Winds and seas will abate tonight and
through the weekend. Light to moderate northerly breezes prevail
this weekend and into next week.

&&

.CLIMATE...
Issued at 110 PM PDT Fri Apr 3 2026

The following are the record high temperatures at the long term 
stations for April 4th and April 5th.

Location          April 4th                April 5th 

Santa Rosa        88 in 1961               90 in 1939
Kentfield         85 in 1957               88 in 1924
San Rafael        86 in 1960               87 in 1957
Napa              86 in 1985, 1960         86 in 1989, 1957
Richmond          89 in 2011               83 in 1989
Livermore         87 in 1959               84 in 1989, 1916
San Francisco     84 in 1985               88 in 1989
SFO Airport       82 in 1985               84 in 1989
Redwood City      86 in 1960               87 in 1989
Half Moon Bay     77 in 2011               74 in 2016
Oakland Museum    85 in 1985               85 in 1989  
San Jose          87 in 1960               89 in 1989
Salinas Airport   86 in 1989, 1960, 1952   95 in 1989

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Saturday for Pt Arena to Pt 
     Reyes 10-60 NM.

&&

$$

SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...Canepa
MARINE...Canepa

Visit us at www.weather.gov/sanfrancisco

Follow us on Facebook, X, and YouTube at:
www.facebook.com/nwsbayarea
x.com/nwsbayarea
www.youtube.com/nwsbayarea


  
Prepared by Boulder-Creek.com Weather at: Fri Apr 3 14:30:02 PDT 2026