FXUS66 KMTR 051133
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
433 AM PDT Sun Jul 5 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1200 AM PDT Sun Jul 5 2026
- Isolated showers possible through the morning
- Cooler temperatures today and Monday before a warming trend
arrives for the second half of the week
- Marine layer stratus develops each evening and overnight before
retreating to the coast each morning and afternoon
&&
.SHORT TERM...
Issued at 1200 AM PDT Sun Jul 5 2026
(Today and tonight)
Stratus is expanding across the coastal regions and into the
valleys, but high clouds associated with elevated moisture are
making it nearly impossible to track the stratus. Radar echoes are
coming in above San Luis Obispo County into southern Monterey
County. However, there haven't been a lot of reports of rain at the
surface , although Paso Robles Airport did report light rain
starting around 1015 PM. The 00Z (5 PM) sounding from Vandenberg
SFB, in addition to aircraft-derived soundings at OAK and SFO,
reveal the main thing keeping the surface generally dry is a layer
of very dry air starting just above the marine layer inversion at
1500-2000 feet up to around 6000-7000 feet above sea level. Within
the layer, dew points as low as -10 degrees Celsius, or 14 degrees
Fahrenheit, were observed, while air temperatures in the middle to
upper 60s were reported, corresponding to relative humidity values
around 12 to 13%. Based on the observed conditions, some showers
coming across the Central Coast and Bay Area can't be ruled out
through the rest of the night through around noon, and I have opted
to put a wide area of slight shower chances (10-15% probability)
through the aforementioned area, although note that showers are
expected to be isolated to widely isolated. As for convective
chances, they are expected to be very small, nearly negligible, as
limited instability and a lack of lifting mechanisms will tamp down
chances for thunderstorms.
Today should see a cooldown with a shortwave trough coming through
the state. High temperatures will range from the middle 70s to the
lower 80s in the inland valleys, up to the upper 80s to lower 90s in
the warmest interior spots, the middle 60s to the middle 70s near
the Bays, and the upper 50s to lower 60s along the Pacific coast.
Stratus coverage should retreat to the immediate coast this
afternoon, along with a clearing of the higher clouds as the pulse
of moisture moves on. Breezy onshore pattern winds should develop in
the afternoon and evening with gusts reaching 20 to 25 mph through
&&
.LONG TERM...
Issued at 1200 AM PDT Sun Jul 5 2026
(Monday through Saturday)
The long term outlook continues to show a balance between ridging
across the Western United States and a series of troughs in the
eastern Pacific through the next few days. Monday will not have a
chance for showers, but otherwise conditions should be similar to
today. Towards the middle and later parts of the week, temperatures
will gradually rise inland as the ridge strengthens and moves into
the Desert Southwest, with a particular emphasis on Wednesday
through Friday when local temperature gradients range from the lower
to middle 60s at the immediate coast to the upper 80s to lower 90s
in the inland valleys, to the triple digits up to 105 within the
warmest spots of southern Monterey County. Beyond the 7-day outlook,
ensemble model cluster analysis is generally in line with the ridge
axis paring back to the Intermountain West for the upcoming weekend
(July 11 to 12), which would support a return to conditions similar
to those expected for the next couple of days, while CPC outlooks
lean towards temperatures remaining above the seasonal average
through the month of July.
&&
.AVIATION...
(12Z TAFS)
Issued at 426 AM PDT Sun Jul 5 2026
A shield of upper level clouds is making is challenging to track
low stratus this morning. That being said, sfc obs shows another
marine layer push even if it was slow developing compared to the
previous few nights. A mix of LIFR to MVFR will impact terminals
through late morning. Expect clearing a tad later this morning
given trailing high clouds. VFR this afternoon with CIGs return
early again tonight. Overall conf is Moderate.
Vicinity of SFO...It took some time, but CIGs finally filled in
over the terminal. Cams do some clearing pockets so it's possible
CIGS many retreat at times this AM. Gusty onshore flow develops
again this afternoon. CIGS return early tonight.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...IFR cigs through late morning. VFR this
afternoon with CIGs returning early tonight.
&&
.MARINE...
(Today through Friday)
Issued at 426 AM PDT Sun Jul 5 2026
A weak cold front to the north will lead to decreasing northerly
flow over the coastal waters today through Monday. Winds are
expected to increase by Monday night with fresh to strong breezes
expected Tuesday and through much of the week. Some gusts near
gale or gale force are possible by Thursday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
SHORT TERM...DialH
LONG TERM....DialH
AVIATION...MM
MARINE...MM
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Prepared by Boulder-Creek.com Weather at: Sun Jul 5 08:30:03 PDT 2026
From the National Weather Service
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