274
FXUS66 KMTR 302245
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
345 PM PDT Sun Jun 30 2024

...New FIRE WEATHER...

.SYNOPSIS...
Issued at 1235 PM 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...
(This evening through Monday)
Issued at 1235 PM PDT Sun Jun 30 2024

A gorgeously warm day across the region today, and a great day to
be outside. Temps warm up a few degrees going into Monday as a
weak upper level trough degrades and moves inland. Highs Monday
look to be in the 90s across the interior, 80s for much of the Bay
shoreline, and 70s along coastal areas. 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...
(Tuesday through next Saturday)
Issued at 1235 PM PDT Sun Jun 30 2024

Significant warmup really begins Tuesday as the very strong ridge
settles in across the West Coast. Not much change in the forecast
through the middle part of the week. Excessive Heat Warning goes
into effect Tuesday morning for interior areas, while lower
elevation locations that were once in the Watch have been
converted to a Heat Advisory given that they will cool off a
little more efficiently at night. Inland and high elevation areas
in the Warning will not see as much overnight relief through the
end of the week. Compressional heating under the ridge will warm
the airmass to near daily record territory above what little will
be left (if anything at all) of the marine layer. Guidance
continues to advertise 850 mb temps around 28 C, peaking
Wednesday. The daily max moving average this time of year is about
26.7 C, and we will be well above the 90th percentile, which is
about 23 C. Did nudge high and low temperatures up by a couple of
degrees Wednesday into the weekend as of this afternoon forecast
package. Far inland areas may actually end up with triple digits
into the weekend and the start of the next week. Left the timing
of the heat hazards as is for now (expiring Friday night), but
will definitely need to look into extending the Excessive Heat
Warning through the weekend. Cluster analysis still shows rather
high uncertainty regarding the breakdown of the ridge into next
week, hence the decision to wait on extending the hazards until
we become more confident over the next couple of days.

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 Excessive Heat Watches or 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 344 PM PDT Sun Jun 30 2024

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

An Excessive Heat Warning is in place for most of our interior
locations, with a Heat Advisory for some locations closer to the
shoreline that may still see minimal influence of the Marine
Boundary Layer. Minimum RH values inland for the upcoming week and
beyond will mostly be in the teens, with some single digit values
in areas of higher elevation. Overnight RH recover will be poor to
non-existent as the heat wave persists through the week, and
potentially into next weekend. The hot and dry conditions continue
to move ERCs into the 70-80 percent range. With the long holiday
weekend, and the many outdoor activities expected, people need to
be careful with any campfires, and fireworks should not be used.
Any wildfire that ignites will have the potential for rapid
spread. Lightning is the only natural ignition for wildfires and
there are no thunderstorms in the forecast.

&&

.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 until 9 PM PDT this evening for Mry Bay-
     Pigeon Pt to Pt Pinos 0-10 nm.

     Gale Warning until 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 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...Behringer
LONG TERM....Behringer
AVIATION...AC
MARINE...AC

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