010
FXUS66 KMTR 301855
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1155 AM PDT Sun Jun 30 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 129 AM PDT Sun Jun 30 2024

Significant warm up still on the way for next week after near normal
temperatures this weekend. Increased fire danger next week as well
with temperatures well above normal and dry conditions through next
weekend.

&&

.SHORT TERM...
(Today and tonight)
Issued at 129 AM PDT Sun Jun 30 2024

An upper level trough is currently impacting the region and will
result in near to slightly above seasonal average temperatures this
afternoon. Mostly sunny conditions are expected once any low clouds
that do develop dissipate. Tonight, expecting temperatures to cool
into the 50`s across much of the region while the higher elevations
remain in the 60`s to lower 70`s. If you live in the interior, now
is the time for any outdoor chores you may need to get done before
the warm up begins on Monday.

&&

.LONG TERM...
(Monday through Saturday)
Issued at 129 AM PDT Sun Jun 30 2024

On Monday ridging will begin to build over the region from the west
and continue to shift eastward throughout the week. Monday kicks off
the first day in a stretch of well above average temperatures with
far interior areas (e.g. Pinnacles National Park and Lake Berryessa)
likely to reach 100F. Tuesday and Wednesday (as currently forecast)
are expected to be the warmest days of the week with afternoon highs
expected to be well into the 100s for inland areas, nearing 110F for
areas such as northern Napa and Sonoma counties, eastern Contra
Costa and Alameda counties, and southern Monterey and San Benito
counties. As such, we have upgraded the watch to an Excessive Heat
Warning for interior parts of the North Bay, East Bay, South Bay,
Santa Cruz Mountains, and interior portions of Monterey and San
Bentio counties. Locations in and around the San Francisco Bayshore,
Northern Monterey Bay, and Northern Salinas Valley are in a Heat
Advisory as temperatures are expected to range from the lower 80`s
to mid 90`s (especially around the San Francisco Bayshore). Coastal
areas will continue to see temperatures ranging from the upper 60s
to the mid 80`s. As such, coastal areas including the City of San
Francisco are not included in any advisories or warnings (this is
subject to change as we move through this heat event). Overnight
minimum temperatures will be an issue with this event as well, with
elevations above about 1000 feet struggling to cool below about 75-
80F starting Tuesday morning. Lower elevations will still see some
degree of marine influence, but by Thursday morning will only cool
into the 60s. There is considerable uncertainty regarding the
pattern after Friday, but the possibility remains that the ridge
hangs out for even longer, thus will prompt the need to extend heat-
related messaging into next weekend.

Heat Safety and Impacts:

By now youre well aware that it is going to be extremely hot next
week with well-above normal temperatures; now lets talk about the
impacts of excessive heat and actions we can take to minimize those
impacts: With extreme heat, and especially prolonged heat events, it
is a marathon, and not a sprint. Our bodies, infrastructure, pets,
and livestock will be under duress from heat over the span of days
as opposed to just a day or two. Given that there is little
overnight relief expected throughout this event, this is where it
really becomes a marathon, and precautionary measures are
necessitated in order to prevent adverse results such as heat
exhaustion and stroke. This is not just for individuals sensitive to
heat, but rather, the entire population. Heat for this duration and
at these temperatures can be dangerous for everyone. Do your body a
favor and if you can, suspend outdoors activities between the hours
of 10am and 7pm on days where Heat Advisories or Excessive Heat
Warnings are in effect. Remain in air conditioning if you have that
available to you in your residence, or seek out air conditioned
environments such as stores, movie theaters, restaurants, libraries,
and cooling shelters.

If you cannot access air conditioned environments, must be outside,
work outdoors, or otherwise, there are other precautionary measures
you can take to keep yourself and your loved ones safe (including
pets!) during excessive heat. Take frequent breaks in the shade and
ensure that you are drinking plenty of cool water, or other
hydrating beverages such as sports drinks with electrolytes. Avoid
DEHYDRATING drinks such as alcohol or caffeinated beverages. That
aside, visiting your city public pool or a lake, river, or ocean can
also help keep you cool, but dont forget the life jacket! If
planning on swimming, stick to where there is a lifeguard, and know
the ocean or river conditions before you get in. Although outside of
our area, its worth repeating: rivers can run fast and cold with
snowmelt in the Sierra Nevada mountains, and cold water shock can
set in quickly, which can lead to loss of muscle control, and
ultimately, drowning. Cold water shock can also set in for ocean-
goers. Have fun at the water, but be smart, be safe, and Know Before
You Go!

Finally, if you do not have air conditioning or cannot access it,
and also cannot access a body of water to stay cool: consider taking
cold showers or baths, turn on those sprinklers or garden hose and
have a fun time in your own makeshift water park, or lay a damp,
cool towel across your head or body. Even just dipping your hands
and feet in cool water can help to abate feelings of excessive heat.
For pets and livestock, make sure they have access to shade
structures or areas, and have clean water freely available to them
at all times. They do not have the same resources or ability to
notify of feeling heat-stressed as we do, so check in on them! If
theyre permanently outdoors, consider giving them a quick rinse-
down with the hose or set up misters, as the evaporation will help
to keep them cool as well.

&&

.AVIATION...
(18Z TAFS)
Issued at 1154 AM PDT Sun Jun 30 2024

VFR through the TAF period for the majority of terminals, the
exception being Monterey Bay. W/NW moderate and gusty winds persist
through the afternoon and evening today. Gusts are generally
expected to be in the 20-25 knot range. Gusty winds slowly ease into
the late night to become light for most terminals.

Vicinity of SFO...VFR through the TAF period. Moderate W/NW winds
will persist through the late night accompanied by strong gusts into
the 30-35 knot range. Although gusts will eventually diminish into
the late night tonight, winds will remain breezy into Monday
morning.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the late evening today, with
breezy onshore winds and occasional gusts near 20 knots. Models
indicate the return of stratus late this evening, however, with
building high pressure, and light offshore winds overnight, there
remains some question as to whether the marine layer and stratus
will be eroded from the coastline, preventing a return of CIGs
overnight at KMRY and potentially KSNS. As it currently stands, have
IFR/LIFR CIGs developing at KMRY overnight though confidence on this
development is only moderate. What is confident is CIG altitudes
(should they develop), as high pressure should keep CIGs
"squished" and confined with only a few hundred feet of the
surface. Any stratus that does form over the terminals is expected
to clear by the late morning of Monday.

&&

.MARINE...
(Today through Friday)
Issued at 1154 AM PDT Sun Jun 30 2024

  The sea state continues to be largely wind driven today with
only light northwesterly and southerly swell present throughout
the waters. Strong northwesterly breezes with occasional gale
force  gusts will continue today and through the mid-week. As high
pressure builds on Monday, the pressure gradient will tighten
leading to more widespread near-gale force gusts across the
waters. Breezes will also turn to become slightly more northerly.
Significant wave heights build to 10-12 feet generally through
the mid-week before beginning an abatement trend.

&&

.FIRE WEATHER...
Issued at 129 AM PDT Sun Jun 30 2024

...Critically low relative humidity expected across the interior
and in higher terrain this upcoming week, especially Tuesday and
Wednesday...

Fire weather concerns will elevate this upcoming week. A Heat
Advisory and Excessive Heat Warning remains in effect for most of
our area away from the coastline for Tuesday through Friday. ERCs
are quickly shifting into the 70ish percentiles and higher in
areas prone to grass fires. The high heat and subsequent low RH
values, poor overnight RH recovery and the associated risks of
fireworks with the Fourth of July - all makes for a combustible
situation, please plan accordingly.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning from 11 AM Tuesday to 11 PM PDT Friday
     for CAZ502>504-506-510-512>518.

     Heat Advisory from 11 AM Tuesday to 11 PM PDT Friday for CAZ508-
     528-529.

PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this
     evening for Mry Bay.

     Small Craft Advisory until 3 PM PDT this afternoon for Pt Arena
     to Pt Reyes 0-10 nm.

     Gale Warning from 3 PM this afternoon to 9 PM PDT this evening
     for Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory until 3 AM PDT Monday for Pt Reyes to
     Pigeon Pt 0-10 nm.

     Small Craft Advisory until 9 PM PDT this evening for Pigeon Pt
     to Pt Pinos 0-10 nm.

     Small Craft Advisory until 9 PM PDT Monday for Pt Pinos to Pt
     Piedras Blancas 0-10 nm.

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

     Gale Watch from Monday afternoon through Tuesday morning for Pt
     Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory until 3 AM PDT Tuesday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...AC
MARINE...AC

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