757
FXUS66 KMTR 172053
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
153 PM PDT Mon Jun 17 2024

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

.SYNOPSIS...
Issued at 153 PM PDT Mon Jun 17 2024

Red Flag Warning remains in effect for the North Bay Interior
Mountains until 8 PM tonight. Dry and breezy conditions continue
into Monday night. Better onshore flow and moisture return by
midweek. Another warming trend on the way for the upcoming
weekend.

&&

.SHORT TERM...
(This evening through Tuesday)
Issued at 153 PM PDT Mon Jun 17 2024

Gusty northwest winds continue to mix down toward the surface this
afternoon, as high as 30 mph in some of our higher locations over the
interior coastal ranges and passes. The gusty winds combined with a
dry air mass producing min RH values as low as 10 percent will
persist for the remainder of this afternoon into the evening hours.
A Red Flag Warning remains in effect until 8pm for the North Bay
Interior Mountains in Napa county. A positively tilted upper level
trough will keep winds elevated wrt the normal diurnal trend
overnight into Tuesday. Embedded weak shortwave ridging will help to
ease surface winds Tuesday, especially inland away from the coast,
however the Salinas Valley will reamin breezy as onshore northwest
surface flow channels inland. Temperatures will remain near seasonal
averages through midweek.

&&

.LONG TERM...
(Tuesday night through next Sunday)
Issued at 145 PM PDT Mon Jun 17 2024

A warm up continues to highlight the extended forecast. Persistent
upper level troughing over our region begins to shift east and
flatten late Thursday into early Friday, continuing into the
weekend. A weak ridge begins to build with the ridge axis just to
our east over the Sierra Mountains Friday afternoon. An increase
in heights and thickness will allow another round of heat to
build, especially the farther you move inland from coastal areas.
Elevated areas of southern Monterey and San Benito county may see
triple digit heat, along with portions of Contra Costa and Alameda
county to the north on Saturday, which should be the peak of this
round of heat.

&&

.AVIATION...
(18Z TAFS)
Issued at 1058 AM PDT Mon Jun 17 2024

Currently VFR at all terminals. VFR through the TAF period for all
terminals except MRY. Thanks to wildfires in the area, high
pressure trapping the smoke, and northerly/northwesterly winds, smoke
will likely be seen across the area, particularly at the
terminals of APC, LVK, and STS, although no significant visibility
reductions are to be expected. With the exception of STS, winds
will become more westerly/onshore through the TAF period.

Vicinity of SFO...Currently VFR with northerly flow. VFR through the
TAF period. Winds will transition to become westerly this afternoon
with gusts up to 30 knots to be expected. Westerly winds diminish
overnight before becoming gusty again tomorrow afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently VFR with northwesterly flow at
both terminals. Winds will be gusty out of the west/northwest
through this evening before diminishing overnight. Moderate
confidence on MRY getting an IFR ceiling with lower confidence on if
it`ll reach SNS.

&&

.MARINE...
(Today through Saturday)
Issued at 1058 AM PDT Mon Jun 17 2024

Widespread strong northerly/northwesterly breezes with near gale-
force gusts will persist through Wednesday. These
northerly/northwesterly breezes will diminish overall beginning
Thursday with strong breezes remaining exclusive to the outer
waters. Significant wave heights will build to 10-12 feet today,
abate through Friday, and build back up to 10-12 feet towards the
end of the period.

&&

.FIRE WEATHER...
Issued at 245 AM PDT Mon Jun 17 2024

...Red Flag Warning remains in effect interior North Bay Mts
Monday...
...Elevated Fire Weather Conditions Through Monday night...

*Breezy to gusty northerly winds, especially higher terrain
*Lowering relative humidity values day and night

Point Wildfire (near Lake Sonoma): Latest heat trends on GOES
satellite and webcams show less heat, but that doesn`t mean the
fire is "out" or contained. For fire specific updates follow
CalFire for the latest. Weather wise, winds near the fire remain
NW with gusts in the 10-20 mph range. Despite the breezy
conditions, RH values have crept upward to moderate, which is
good. Transport flow continues to show smoke impacts SE of Lake
Sonoma stretching into the East Bay. This is also being reflected
at the surface with AQ sensors showing poor AQ. For more AQ info
check BAAQMD.

Overall fire weather concerns: No change with ongoing Red Flag
for interior North Bay for later today. The northerly shift in
winds are still on track with gusts in the 25-40 mph. Winds will
be strongest over the higher terrain of the North and East Bay.
While winds increase RH values will begin to plummet. Hi-res
guidance continues to advertise RH values dropping into the upper
single digits to lower teens this afternoon. The greatest impact
will be over the North Bay Interior Mts - hence the Red Flag.
Elsewhere, conditions will be marginal for Red Flag, but still
elevated nonetheless. Winds remain breezy offshore for Monday
night into Tuesday keeping elevated fire weather concerns in play.
Better relief arrive Tuesday into Wednesday with increased
onshore flow.

Longer range forecast will need some watching as hot and dry
conditions return to the district.

MM

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Red Flag Warning until 8 PM PDT this evening for CAZ504.

PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay-Pt
     Arena to Pt Reyes 10-60 NM-SF Bay N of Bay Bridge.

     Small Craft Advisory from 3 PM to 9 PM PDT Tuesday for SF Bay N
     of Bay Bridge.

     Small Craft Advisory from 9 AM Tuesday to 3 AM PDT Wednesday for
     Mry Bay.

     Small Craft Advisory until 3 AM PDT Wednesday for Pigeon Pt to
     Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to
     Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

     Gale Warning until 9 PM PDT this evening for Pt Pinos to Pt
     Piedras Blancas 0-10 nm.

     Gale Warning from 3 PM Tuesday to 3 AM PDT Wednesday for Pt
     Pinos to Pt Piedras Blancas 0-10 nm.

     Gale Warning from 9 PM this evening to 3 AM PDT Tuesday for Pt
     Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...JM
LONG TERM....JM
AVIATION...Sarment
MARINE...Sarment

Visit us at www.weather.gov/sanfrancisco

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