FXUS66 KMTR 240114
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
614 PM PDT Thu Apr 23 2026
...New AVIATION...
.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 126 PM PDT Thu Apr 23 2026
(This evening through Friday)
Radar is finally quiet this afternoon after a period of somewhat
active weather. Visible satellite shows mostly clear skies around
the region with a few pop up CU hugging the hills. Increased
insolation this afternoon has led to a warmer temperatures across
the board.
Stepping back and looking at the longwave pattern over EPAC and
CONUS reveals an interesting pattern. The EPAC is highly
amplified with a solid ridge extending into E AK and W BC with a
low off the CA coast with a rex block vibe. Farther east two
pronounced upper lows spin, one north of MT and the other east of
Nova Scotia with a ridge smacked in between with an omega block
vibe. In other words a little bit of a traffic jam in the upper
atmosphere. That being said, we do see some minor movement on the
small scale and closer to home. A weak embedded shortwave/fuzzy
upper low off the CA coast is slowly moving eastward. As this
feature moves eastward high clouds will increase over the region
tonight and Friday. The higher clouds may limit fog production
tonight, but some low stratus will be possible. Interestingly,
some of the CAMs resolve some forecast 1KM radar reflectivity
tonight. Forecast is dry for Friday morning, but a few echoes may
appear on radar. Increased cloud cover will also lead to cooler
temperatures on Friday with highs dropping below seasonal averages
again.
&&
.LONG TERM...
Issued at 126 PM PDT Thu Apr 23 2026
(Friday night through next Wednesday)
A trend that emerged a few days ago is still on track for the
upcoming weekend, "wetter" and cooler. Broad troughiness remains
over region with re-enforcing upper lows. Another upper low is on
track to move over the region Friday night into Saturday and
subsequent vort maxes Saturday into Sunday. These features
combined with the northern fringes of sub-tropical moisture
pulses will lead to some drizzle/light rain showers Friday night
through Sunday morning. Not expecting much in the way of
accumulation, trace to a few hundredths. Areas most favored will
be coastal mts with enhanced low level lift. Temperatures for the
upcoming weekend will be below seasonal averages with highs in
the upper 50s and 60s.
By early next week 500mb heights begin to rebound with warming
850mb temps kicking off a gradual warming and drying trend. No
precip in the forecast Monday through Wednesday.
&&
.AVIATION...
(00Z TAFS)
Issued at 613 PM PDT Thu Apr 23 2026
Calm weather continues this afternoon into the evening with some
high clouds making their way onshore. Expect VFR conditions through
the evening hours. There is a stratus deck to our NW that is set to
impact all TAF sites (to varying degrees) late tonight into the
early morning resulting in MVFR conditions and some brief IFR
periods. Both KSTS and KAPC will be the most impacted this TAF
period as they will experience IFR conditions due to a combination
of stratus and fog. KHAF will also remain in MVFR conditions due to
stratus beginning 06Z Friday. West to NW winds are forecast to
decrease overnight and increase to moderate strength by Friday
afternoon, which will help mix out the lower CIGs at most terminals.
Vicinity of SFO...Persistent and moderate onshore flow is expected
to continue through the TAF period. Westerly winds will help to
bring in the coastal stratus deck causing CIGs to fall within MVFR
criteria around 11Z Friday. The winds will also become light at this
time with a brief period of IFR conditions from 12-16Z. By 19Z
Friday, the winds are forecast to increase and CIGs will rise
slightly, but will remain MVFR.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR conditions with moderate westerly winds
continue through the evening hours. As stated previously, the MVFR
CIGs caused by the coastal stratus deck is expected to impact
Monterey Bay early morning around 10Z Friday and will stick around
until the early afternoon (19Z Friday). Wind speeds should also
increase by 19Z which will assist in the transition back to VFR.
&&
.MARINE...
(Today through Tuesday)
Issued at 924 AM PDT Thu Apr 23 2026
Moderate north breezes this morning will develop into a northwest
breeze this afternoon. Choppy seas at times today will begin to
subside Friday and continue into the weekend. Light rain and
drizzle return to this weekend.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 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 9 AM PDT Friday for Pt Arena to Pt
Reyes 10-60 NM.
Small Craft Advisory until 3 AM PDT Friday for Pigeon Pt to Pt
Pinos 10-60 NM.
&&
$$
SHORT TERM...MM
LONG TERM....MM
AVIATION...Navarrete/RC
MARINE...KR
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Prepared by Boulder-Creek.com Weather at: Thu Apr 23 20:30:02 PDT 2026
From the National Weather Service
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