223
FXUS66 KMTR 301133
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
433 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...
(12Z TAFS)
Issued at 432 AM PDT Sun Jun 30 2024

IFR-LIFR ceilings in the northern Monterey Bay have for the most
part stayed away from the Monterey bay terminals, although patchy
ceilings could impact the terminals through sunrise. Otherwise,
generally high confidence of VFR into this evening, with breezy and
gusty onshore winds developing in the afternoon. Marginal LLWS
concerns continue for the rest of this morning and tonight as
surface winds decouple from flow aloft, especially along the coast,
but outside of STS the magnitude is not severe enough to note in the
TAFs. Model output suggests stratus coming through the San Mateo
peninsula into the northern SF Bay terminals late tonight and Monday
morning, but confidence remains low and the immediate coast and
Monterey Bay look more likely to see stratus tonight.

Vicinity of SFO...VFR through at least this evening. Northwest winds
remain breezy overnight before strengthening Sunday afternoon. Gusts
could reach 30 knots, but low confidence that they will reach 35
knots or above. Will continue to monitor observations and further
model guidance through the day. Some model output suggests some IFR-
LIFR stratus will flow over the San Mateo peninsula and impact the
terminal late tonight into Monday morning, but confidence is low the
TAF remains VFR throughout.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR-LIFR ceilings remain mostly confined to
the northern Monterey Bay, and have occasionally impacted SNS but
not at MRY. Confidence in stratus impacts at MRY is decreasing
and as such have turned the prevailing ceiling into a TEMPO group.
Breezy onshore winds develop this afternoon, and diminish into
the evening as stratus returns to MRY and later SNS.

&&

.MARINE...
(Today through Friday)
Issued at 432 AM PDT Sun Jun 30 2024

  Surface high pressure over the Eastern Pacific Ocean will be the
driving feature through the period. Northwesterly breezes with
occasional gale force gusts will continue today. As the
aforementioned surface high pressure builds on Monday, the
pressure gradient will tighten and breezes will become northerly
with gale force gusts expected over the outer waters through
Wednesday. Significant wave heights build to 10-15 feet through
Tuesday before beginning an abating trend towards the end of the
period.

&&

.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 from 9 AM this morning to 9 PM PDT this
     evening for Pigeon Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory from 9 AM this morning to 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 9 AM PDT Monday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...RGass
LONG TERM....RGass/Behringer/Clouser
AVIATION...DialH
MARINE...DialH

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