877
FXUS66 KMTR 201815
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1115 AM PDT Thu Jun 20 2024

...New SYNOPSIS, SHORT TERM, LONG TERM, AVIATION, MARINE...

.SYNOPSIS...
Issued at 1019 AM PDT Thu Jun 20 2024

Gorgeous day across the interior today with temps on the rise.
Warming trend peaks Saturday...Heat Advisory in effect for inland
areas Saturday with moderate HeatRisk. Temps cool Sunday into
early next week.

&&

.SHORT TERM...
(This afternoon through Friday)
Issued at 1115 AM PDT Thu Jun 20 2024

No major change in the forecast today. Ample sun for areas away
from the coast and temperatures a couple of degrees warmer today
compared to yesterday. Some high clouds across northern portions
of the CWA as some residual upper level moisture swings through
associated with the decaying trough. By Friday afternoon, 500 mb
heights rise rapidly as the trough fully decays and the ridge sets
in. This will likely result in the most drastic day-to-day
temperature change of the week with high temps Friday generally
5-10 degrees warmer than today. Marine layer compression due to
large scale subsidence into the weekend will also result in
clearer conditions for coastal areas this weekend.

&&

.LONG TERM...
(Saturday through next Wednesday)
Issued at 1115 AM PDT Thu Jun 20 2024

Saturday is expected to be the warmest day of this short heat
event with another 4-7 degree increase from Friday`s temps.
Generally looking like the lower 100s for far inland areas, a
spread in the 90s for most of the North Bay, South Bay, and
interior valleys around Monterey Bay, and the 60s to mid 70s for
coastal areas. A Heat Advisory is in effect Saturday for interior
areas of the North Bay, East and South Bay (including San Jose),
and the interior Central Coast. HeatRisk will be in the "moderate"
category for these areas, which means that the heat will affect
most individuals sensitive to heat...especially those without
effective cooling or adequate hydration. You may think you`re used
to the heat, but it`s still relatively early in the season and
your body may think otherwise. Take care of yourself and others.
There is some degree of relief noted in overnight lows,
especially at elevations where most people live. Coastal and Bay
Area locations will see lows in the 50s, while further inland
places will be in the lower 60s. Locations above about 2000 feet
may struggle to cool lower than the low 70s overnight Friday and
Saturday nights. A notable cool down by about 8-10 degrees will
take place Sunday, but warmer weather persists through early next
week.

&&

.AVIATION...
(18Z TAFS)
Issued at 1115 AM PDT Thu Jun 20 2024

VFR through the afternoon today for most terminals, with breezy
onshore winds in the 10-15 knot range. Stratus will make an early
push into terminals this evening, bringing initially MVFR CIGs.
Beyond sunset, CIGs are expected to lower for most terminals to
become IFR in the overnight. Winds light overnight.

Vicinity of SFO...VFR through the afternoon today, breezy onshore
winds. Low clouds will begin to enter the terminal vicinity in the
late afternoon to early evening. MVFR CIGs develop very briefly
initially, but are expected to quickly become IFR as stratus
continues to push inland. IFR CIGs last through sunrise of Friday,
but are expected to clear to VFR in the later morning.

SFO Bridge Approach...VFR through the daytime today, but expected to
become IFR into the evening and lasting through Friday morning as
stratus envelops much of the SF bay.

Monterey Bay Terminals...MVFR CIGs persist this morning as a strong
inversion helps to keep the marine layer and accompanying stratus in
place. However, towards noon, stratus should briefly clear to VFR.
VFR is only expected to last a handful of hours this morning.
Onshore and breezy winds this afternoon will help to advect stratus
inland towards the late afternoon to early evening, ushering in
MVFR/IFR conditions. IFR then lasts through the night and Friday
morning, high confidence. There remains some question as to whether
CIGs may briefly dip into LIFR territory early Friday morning,
however confidence on this is too low, therefore have excluded from
the TAF.

&&

.MARINE...
(Today through Tuesday)
Issued at 1115 AM PDT Thu Jun 20 2024

Fresh northwest winds persist, with the strongest gusts across
the northern waters causing hazardous conditions for small craft.
Significant wave heights of 6-8 feet will persist until the end of
the week, then build back up to 10-11 feet over the outer waters
for the weekend, when northwest winds increase once again over
much of the waters. Light southerly swell continues to move
through the waters today, accompanied by moderate NW swell.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory from 11 AM to 10 PM PDT Saturday for CAZ504-510-
     513>518.

PZ...Small Craft Advisory from 3 PM this afternoon to 3 AM PDT Friday
     for Pt Arena to Pt Reyes 0-10 nm.

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

&&

$$

SHORT TERM...Behringer
LONG TERM....Behringer
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