-- Discussion containing changed information from previous version are highlighted. --
780
FXUS66 KMTR 240659
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1159 PM PDT Sun Jun 23 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 237 AM PDT Sun Jun 23 2024

Somewhat cooler temperatures in the interior today, continuing into
the beginning of the work week with a slight cooldown midweek. Very
low chance of elevated convection and associated dry lightning in
the southern Central Coast.

&&

.UPDATE...
Issued at 906 PM PDT Sun Jun 23 2024

Forecast is looking to be on track for tonight. No updates were
made. Evening satellite showed clearing skies in the visible with
the last of the daylight and nighttime microphysics difference
band is showing some low clouds lingering in Monterey Bay. Per
usual in the region, look for low clouds to develop overnight in
coastal areas. However, with high pressure ridging into the
region, these low clouds will be hard pressed to make much inland
intrusion. Overall a classic Bay Area / Central Coast summertime
pattern.

&&

.SHORT TERM...
(This evening through Monday)
Issued at 115 PM PDT Sun Jun 23 2024

Stratus and/or fog has retreated to the coast as of early afternoon
with coastal areas expected to warm into the upper 50`s to 70`s.
However, inland areas will remain quite warm this afternoon and
reach 5-15 degrees above normal for this time of year, reaching into
the mid 80`s to upper 90`s with a few of the warmest interior
locations approaching 100 degrees. Only a few isolated spots across
the interior will reach Moderate HeatRisk, thus we don`t have a Heat
Advisory in effect for today.

As for high-based convection, looking less likely to see development
today as mid-upper level moisture is not sufficient enough. Looking
like the potential (10-15%) is still there for Monday evening
through Tuesday morning however, especially across the Central
Coast. Tomorrow`s high temperatures will be similar to this
afternoon (maybe a few degrees cooler) with the pattern changing
very little, other than increased moisture aloft from the south.

&&

.LONG TERM...
(Monday through Saturday)
Issued at 237 AM PDT Sun Jun 23 2024

The mid-layer moisture continues to push through the region and will
push across the Bay Area on Tuesday. In addition to the mid-to-
upper level clouds that will typically accompany the moisture, the
chance for elevated convection mainly across the Central Coast
remains through Tuesday. Interior temperatures will cool off on
Wednesday and Thursday, with highs in the 80s to the mid 90s, as
an upper level trough comes into the West Coast and promotes
improved onshore flow. CPC outlooks continue to suggest that
temperatures above seasonal averages will continue into the first
week of July.

&&

.AVIATION...
-- Changed Discussion --
(06Z TAFS)
Issued at 1159 PM PDT Sun Jun 23 2024

The marine layer is approximately 1000 feet deep. The Sunday
evening Oakland upper air sounding showed the precipitable water
was 0.48" which is a dry troposphere for late June, near the 10th
percentile. The lack of water vapor will allow for good longwave
radiative cooling to space (loss of heat) overnight assisting
coastal stratus and fog /LIFR-IFR/ redevelopment. Inland it`s a
near high confidence VFR forecast. To the south near the
Monterey/San Luis Obispo county line the leading gradient of
increasing precipitable water (near 1") is slowly advancing
northward from southern California, the Sunday evening Vandenberg
upper air sounding showed water vapor mostly focused near 12000
feet agl; additionally positive convective potential at this level
was met with convective inhibition i.e. no thunderstorm development
noted along the more immediate coast. A slow northward progression
of mid level water vapor will reach our forecast area, convective
parameters for mid level convection steadily increase late tonight
and Monday, however 700-500 mb thermal troughing is rather ill-defined
tonight and Monday until perhaps slightly more structured for mid-
level upward forcing Monday afternoon and/or evening. For the time
being, decided to leave out convection in the 06z TAFs.

Vicinity of SFO...Moderate to high confidence VFR forecast for the
period. Northwest to west wind 5 to 12 knots through Sunday morning,
increasing to 14 to 22 knots Sunday afternoon and evening.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...An eddy circulation has developed over
the northern Monterey Bay area, with stratus and fog caught up in
the circulation. KWVI has reported IFR ceiling. High resolution
model output show gradually increasing surface to near surface
humidity overnight, increasing the chances IFR develop at KMRY and
KSNS overnight. Stratus and fog /LIFR-IFR/ mixing out by late
Sunday morning. Mid to late Sunday afternoon and evening will need
to keep an eye to the sky for potential mid level convection, for
now thunderstorm(s) not in current TAFs.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
(Tonight through next Saturday)
Issued at 1102 PM PDT Sun Jun 23 2024

Hazardous conditions for small crafts persist across the northern
coastal waters through the early work week. Fresh to strong
northwest winds continue over the northern coastal waters. Fresh
gusts remain possible over the southern outer waters. Beginning
this afternoon, near gale force gusts will develop over the
northern outer coastal waters. Gusts will diminish across the
northern outer coastal waters beginning Monday afternoon and
gradually weakening to moderate to fresh strength by Tuesday
morning. Significant wave heights over the northern waters will
build to 10-11 feet through Monday before wave heights abate below
10 feet by Tuesday.
-- End Changed Discussion --

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CA...Coastal Flood Advisory until 4 AM PDT Monday for CAZ506.

PZ...Small Craft Advisory until 9 AM PDT Tuesday for Pt Arena to Pt
     Reyes 10-60 NM.
-- End Changed Discussion --

&&

$$

SHORT TERM...BFG
LONG TERM....RGass
AVIATION...Canepa
MARINE...SO

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