243
FXUS66 KMTR 221552
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
852 AM PDT Sat Jun 22 2024

...New UPDATE, MARINE...

.SYNOPSIS...
Issued at 1250 AM PDT Sat Jun 22 2024

Hot temperatures peak today with a Heat Advisory in effect later
this morning through the evening for the interior regions with a
moderate risk of heat-related illnesses. Temperatures moderate
through the early part of next week, but remain warm across the
interior.

&&

.UPDATE...
Issued at 851 AM PDT Sat Jun 22 2024

Ceilings are lower than this time yesterday with areas of patchy
fog, yet less of an inland extent to the cloud cover. However,
conditions are quickly mixing out over inland areas and will
continue this trend with more breaks in the cloud cover near the
coast this afternoon. As such, inland areas remain under a Heat
Advisory from 11 AM this morning until 10 PM this evening as
HeatRisk reaches into the moderate category. That said, the ongoing
forecast remains on track with no updates anticipated this morning.

&&

.SHORT TERM...
(Today and tonight)
Issued at 1250 AM PDT Sat Jun 22 2024

Satellite imagery shows marine layer stratus developing across the
coastal regions with intrusions through the Golden Gate, across the
East Bayshore, into Napa County, across the Monterey Bay region and
down into the Salinas Valley. Right now, we`re not expecting as much
interior development tonight, as the marine layer has compressed
through the previous day, as exemplified by the Fort Ord profiler
showing a marine layer depth around 1000-1250 feet. Low temperatures
this morning range from the low 50s to near 60 in the lower
elevations, with the lower temperatures expected where there is
marine layer stratus tonight, up to the upper 60s to lower 70s in
the higher elevations.

The warmest temperatures of the brief heat event are expected to
develop later today. A Heat Advisory will come into effect later
this morning through the evening for the interior North Bay
mountains, interior East Bay, the Santa Clara Valley and eastern
Santa Clara hills, the interior Central Coast mountains, the
southern Salinas Valley, and the Santa Lucia mountains. Areas under
the Heat Advisory should expect highs from the mid 90s into the mid
100s, and a Moderate HeatRisk. This means that there is a risk of
heat-related illnesses for most people sensitive to heat, including
children, the elderly, pregnant women, those working or living
outside, and those with certain medical conditions. Elsewhere across
the region, high temperatures are expected to reach the upper 80s to
mid 90s in the inland North Bay valleys, the mid 70s to upper 80s in
the Bayshore and the northern Salinas Valley, and the 60s into the
low 70s for the Pacific coast.

Here are heat safety tips:

* Stay hydrated and drink plenty of fluids.
* Wear lightweight, light-colored clothing.
* Reduce time spent outdoors or stay in the shade.
* Never leave people or pets unattended in vehicles.
* Use sunscreen if going to the coast or the pool.

&&

.LONG TERM...
(Sunday through Friday)
Issued at 1250 AM PDT Sat Jun 22 2024

Sunday should be noticeably cooler as an upper level trough to our
west begins to promote stronger onshore flow. High temperatures will
drop into the mid 80s to the low 90s in the interior valleys
(perhaps close to 100 in the warmest spots), the 70s into the lower
80s along the Bayshore, and the upper 50s to the 60s along the
coast. The ridge will begin to erode and shift eastward with an
upper level low approaching the Pacific Northwest, but the general
weather pattern should remain relatively unchanged, with perhaps a
few degrees of cooling towards the latter part of the next work
week. The latest CPC outlook continues to suggest temperatures near
or above seasonal averages, and precipitation at or below seasonal
averages (noting that at this point in the year, seasonal average
precipitation is very low) continue into the first days of July.

&&

.AVIATION...
(12Z TAFS)
Issued at 442 AM PDT Sat Jun 22 2024

LIFR-IFR in stratus and fog is developing along the coastline and
extending into the Bay Area and the Salinas Valley. Inland it`s
VFR. Under upper level high pressure, compressional warming has
strengthened the marine layer temperature inversion per recent
coastal profiler and Oakland upper air data. The HRRR model has a
good handle on a weak southeasterly wind within a weak surface
trough along the North Bay coast, stratus and fog have been moving
northward along the coast since approx midnight per satellite
imagery. Coastal fog is reducing the surface visibility to 1/2-1/4
mile or less, including occasionally lowering to less than 1 mile
in mist as far north as STS Airport. Conditions improving to MVFR-VFR
along the coastline today, coastal stratus and fog /LIFR-IFR/
redeveloping tonight and Sunday morning.

Vicinity of SFO...IFR stratus ceiling developing nearby SFO, tempo
bkn IFR ceiling forecast 12z-15z this morning. Otherwise VFR today
and tonight. Surface wind northwest 5 to 10 knots, becoming westerly
and increasing to near 15 knots in the afternoon. Westerly wind
decreasing and becoming light tonight and Sunday morning. IFR ceiling
forecast late tonight and Sunday morning /10z/.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...LIFR-IFR in stratus and fog this morning.
Conditions improving to MVFR-VFR by late morning and/or early
afternoon, coastal stratus and fog /LIFR-IFR/ redeveloping tonight
and Sunday morning. Onshore winds 5 to 15 knots strongest in the
afternoon and early evening.

&&

.MARINE...
(Today through Thursday)
Issued at 851 AM PDT Sat Jun 22 2024

Strong, northwest winds with near gale force gusts possible
continue into the work week over the northern outer coastal
waters. Fresh to the occasional strong gusts remain possible over
the southern outer coastal waters and portions of the northern
interior coastal waters. Elevated wave heights between 10 to 12
feet continue over the northern outer waters with significant wave
heights expected to diminish below 10 feet by the middle of the
work week. Conditions hazardous to small crafts will remain
possible through the middle of the work week across the northern
outer coastal waters. Light southerly swell continues to move
through the waters, accompanied by moderate NW swell through the
beginning of next week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 10 PM PDT this evening for CAZ504-510-
     513>518.

PZ...Small Craft Advisory until 9 AM PDT Monday for Pt Arena to Pt
     Reyes 10-60 NM.

     Small Craft Advisory until 9 PM PDT this evening for Pigeon Pt
     to Pt Pinos 10-60 NM.

&&

$$

UPDATE...RGass
SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Canepa
MARINE...Kennedy

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