FXUS66 KMTR 230703
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1203 AM PDT Thu Apr 23 2026

...New SHORT TERM, LONG TERM...

.KEY MESSAGES...
Updated at 1201 AM PDT Thu Apr 23 2026

 - Seasonal temperatures and dry conditions return today

 - Potential for rain/drizzle and slightly cooler temperatures 
   this weekend into early next week

 - Warming trend begins early to mid next week

&&

.SHORT TERM...
Issued at 1201 AM PDT Thu Apr 23 2026
(Today and tonight)

KMUX has been allowed to transition back into clear air mode as 
shower activity has ended across the region. Relatively moist 
conditions and light winds overnight will lead to some potential for 
patchy fog to develop across the valleys. Latest HRRR guidance 
supports a slightly higher chance for patchy fog to develop within 
the Santa Clara Valley and potentially within North Bay Valleys. Fog 
development would be most likely in the early morning hours/right 
around sunrise. As this may run into the early morning commute, if 
you encounter fog remember to slow down and allow extra time to 
reach your destination. 

Morning temperatures will be seasonable with lows generally in the 
40s. Portions of the Eastern Santa Clara hills, the Gabilan Range, 
and the Santa Lucia Range will drop into the mid to upper 30s. High 
temperatures warm up well, however, as a weak, progressive ridge 
moves through southern and central California. High temperatures 
will be in the low to mid 70s across the interior and 50s to 60s 
along the coastline. Temperatures across the lower elevations will 
be seasonal to seasonally warm while temperatures across the higher 
terrain are below normal. No other concerns in the short term as dry 
weather prevails. Winds remain light and onshore today with 
diurnally breezy conditions expected across the valleys. 

&&

.LONG TERM...
Issued at 1201 AM PDT Thu Apr 23 2026
(Friday through Wednesday)

By Friday, the upper level ridge will begin its eastward exit and 
weak upper level troughing will return over the Western US. This 
trough is associated with a deep upper level low that will remain 
situated over Montana/the Dakotas through the weekend before exiting 
the region early next week. As weak troughing returns, it will allow 
a much cooler airmass to filter in over the West Coast Saturday 
through early next week. Initial guidance shows 850 mb temperatures 
running between 2-4 degrees Celsius which is between the 10th to 
25th percentiles for 850mb temperatures recorded by OAK. For 
comparison the daily mean 850 mb temperatures are closer to 7 to 8 
degrees Celsius. What does that look like at the surface? High 
temperatures on Friday will be fairly seasonal in the upper 60s to 
low 70s across the interior and 50s to 60s along the coast. Saturday 
temperatures will cool by around 5 degrees across the interior where 
widespread 60s are expected (coastal temperatures remain in the 50s 
to 60s). We can expect similar temperatures on Sunday before a 
slight warming trend kicks off Monday as 850mb temperatures warm 
(becoming more seasonal). This warming trend will see temperatures 
returning to the low to mid 70s across the interior with 
temperatures warming by a few degrees each day through the remainder 
of the long term forecast. Overnight low temperatures remain 
seasonable through the extended forecast with slightly cooler 
temperatures expected across the higher elevations of the eastern 
Santa Clara Hills, the Gabilan Range, and the Santa Lucia Range.

Another factor to consider in planning your weekend is the 
possibility of rain. Currently, it is looking like we might get some 
light rain but it will not be as impressive as the system we just 
had. Ensemble guidance is alternating between drizzle to a few 
tenths of an inch (0.1-0.2") possible. The higher chances for light 
rain are across the Central Coast with more drizzly conditions 
likely across the Bay Area. Higher precipitation totals (compared to 
us) are more likely across Southern California where the main 
moisture plume is oriented against. Either way, it is likely to be a 
drizzly weekend but the incoming rain will be light and beneficial. 
Ensembles are hinting at additional light, beneficial rain being 
possible mid to late next week as the upper level pattern remains 
unsettled.


&&

.AVIATION...
(06Z TAFS)
Issued at 1020 PM PDT Wed Apr 22 2026

The drying trend continues for the 06Z TAFs. Light winds persist 
overnight and into the early morning hours. Winds increase during 
the day becoming moderate. Some high clouds will move over the area 
late morning Thursday. An intrusion of low-level CIGs will move 
onshore Thursday night as winds reduce. KHAF will be the first to be 
impacted which is then followed by KOAK and KSFO resulting in MVFR 
conditions towards the end of the TAF period. All other sites will 
be VFR.

Vicinity of SFO...Westerly winds are forecast for the majority of 
the TAF period with a brief period of northerly winds in the late 
morning on Thursday. By the early afternoon, the winds will shift 
west again while becoming moderate and gusty through the night. 
Mainly VFR this TAF period up until 11Z Friday when CIGs lower to 
MVFR conditions.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the TAF period. Winds are 
becoming light and variable and cloud cover has mostly cleared. Low 
clouds look to form on the mountain tops in the area overnight, but 
don't look to affect the TAF sites. Those clouds erode into the 
early morning with moderate west to northwest winds affecting the 
region into the late morning. These last into the early night before 
reducing. 

&&

.MARINE...
(Tonight through next Tuesday)
Issued at 1020 PM PDT Wed Apr 22 2026

Showers have dissipated leading to calmer and clearing conditions.
A moderate north breeze will develop into a fresh northwest
breeze by Thursday afternoon. Wind and seas will begin to
gradually subside on Friday, continuing into the weekend.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this 
     evening for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt 
     Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt 
     Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory until 3 PM PDT Friday for Pt Arena to Pt 
     Reyes 10-60 NM.

     Small Craft Advisory from 3 PM this afternoon to 3 AM PDT Friday 
     for Pigeon Pt to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...Navarrete
MARINE...Murdock

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Prepared by Boulder-Creek.com Weather at: Thu Apr 23 04:30:02 PDT 2026