749
FXUS66 KMTR 282143
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
243 PM PDT Sun Apr 28 2024

...New SHORT TERM, LONG TERM...

.SYNOPSIS...
Issued at 1227 AM PDT Sun Apr 28 2024

High pressure brings quiet weather and slowly warming temperatures
this week. Breezy onshore winds will keep temperatures along the
coast cooler however.

&&

.SHORT TERM...
(This evening through Monday)
Issued at 225 PM PDT Sun Apr 28 2024

Almost a repeat of Saturday weather wise: ample sunshine with fair
weather cumulus, warming trend continues, and breezy to gusty
onshore flow. Warmest inland temperatures will approach 80
degrees this afternoon, but will likely fall short by a degree or
two. Closer to the coast and bays is much cooler thanks to the
persistent onshore flow off the chilly coastal waters. Onshore
flow is still showing gusts of 30-40 mph along the coast,
gaps/passes, and higher terrain. For the curious weather watcher
looking at satellite imagery this afternoon it`s always impressive
to see standing wave clouds form upwind of coastal terrain. Case
in point are the line of the clouds near Pt Reyes, San Mateo
coast, and Monterey Peninsula. For the weather geek, flow in the
marine boundary layer is forced to decelerate as it hits the
terrain causing a wave like feature to form and in this case an
undular bore or visually the standing wave cloud.

Large zonal flow remains over the region tonight and early Monday.
A tight shortwave trough will zip through the zonal flow just
north of CA early Monday. While this feature will be dry it will
however give a re-enforcing shot of northwest winds over the
coastal waters, gaps/passes, and higher terrain on Monday. While
not strong enough for a Wind Advisory, gale force conditions will
impact the coastal water. Similar to Sunday morning, patchy
stratus will once again be possible early Monday. Monday afternoon
will once again feature mostly sunny skies, patchy coastal
stratus, and mild temperatures across the interior.

&&

.LONG TERM...
(Monday night through next Sunday)
Issued at 236 PM PDT Sun Apr 28 2024

Subtle riding offshore/barely for CA develops through midweek as
an upper low digs/sweeps through the Great Basin. Pretty quiet
weather for the week as temperatures will warm gradually and
onshore winds decrease. Interior locations will see more
widespread 80s with Heat Risk values creeping into the minor
category. Patchy night and morning stratus will be possible each
day.

Heading into next week the longwave pattern begins to change and
become more amplified. An upper low will move into the PacNW by
Friday and become more of an open wave/upper trough by Saturday.
This feature will bring the tail end of a weak front across
NorCal. As such, light rain is now in the forecast for the far
North Bay Saturday night/Sunday morning. Not much QPF, but a few
hundredths possible at this point.

Taking a peak farther down the road, clusters and ensembles show a
deeper low/upper trough moving into the PacNW the first week of
May. This will likely bring cooler temperatures and increased
chances for precip. Latest CPC 8-14 day outlook follows that
thinking through May 12.

&&

.AVIATION...
(18Z TAFS)
Issued at 1040 AM PDT Sun Apr 28 2024

Morning MVFR/IFR cigs continue to dissipate with KSFO the only one
still showing a cig. The bigger story through the taf period will
be the winds. Stronger onshore flow will keep gusty winds in
place. VFR tonight with the exception of a few cigs impacting KMRY
and KSNS late tonight through early Monday.

Vicinity of SFO...Classic pesky feed situation for KSFO as cigs
spill over the runway. Did amend taf early for cigs through 18Z.
Latest meso vis satellite finally shows a thinning of the feed
with cigs staying closer to the gap. Winds are strong out of the
NW with gusts close to 35 kts this afternoon. The sustained winds
will likely impact runway pattern on the 01s due to strong
crosswind. AWW criteria will be very close, but for now gusts to
34 kts in the taf.

SFO Bridge Approach...No impact from cigs. SKC. Still dealing with
gusty NW winds through approach zone.

Monterey Bay Terminals...VFR for now. Will need to keep an eye out
for developing cigs through the afternoon for KMRY as strong NW
flow piles up over the peninsula. Do have cigs returning late
tonight.

&&

.MARINE...
(Today through Friday)
Issued at 1040 AM PDT Sun Apr 28 2024

High pressure over the Eastern Pacific and low pressure inland
will maintain strong northerly winds over the coastal waters and
bays today. Winds will be strongest over the outer waters and
along the Big Sur coast. The strong winds will produce fresh steep
wind waves and hazardous conditions. Winds continue to increase
during the first half of the week lasting through Thursday.
Moderate period northwesterly swell will continue to move through
the waters through Thursday causing wave heights up to 12 feet.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Monday for SF Bay N of Bay
     Bridge.

     Small Craft Advisory until 9 PM PDT Monday for Mry Bay-Pigeon Pt
     to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory until 9 AM PDT Monday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt
     Reyes 10-60 NM.

     Gale Warning from 9 AM to 9 PM PDT Monday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt
     Reyes 10-60 NM.

     Gale Warning until 9 PM PDT Monday for Pt Pinos to Pt Piedras
     Blancas 0-10 nm.

&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...MM
MARINE...MM

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