831
FXUS66 KMTR 281712
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1012 AM PDT Fri Jun 28 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 251 AM PDT Fri Jun 28 2024

A well established marine layer and onshore flow will keep
temperatures cool near the coast while inland areas warm to into
the 90`s throughout the weekend. Pattern change causes a warm up
early next week, with monitoring potential excessive heat for the
second half of next week.

&&

.SHORT TERM...
(Today and tonight)
Issued at 251 AM PDT Fri Jun 28 2024

Low clouds are redeveloping near the coast early this morning,
especially around the San Fransico Peninsula and the Monterey Bay
region. These clouds will retreat to the coast by this afternoon
with maximum temperatures expected to warm into the upper 80`s to
mid 90`s across the interior with 60`s and 70`s near the coast.
Tonight, expecting low clouds to return to the coast with minimum
temperatures dropping into the upper 40`s in the North Bay and along
the San Francisco Peninsula to low-to-mid 50`s elsewhere. Similar
day-to-day trends will continue throughout the weekend with a slight
warming trend.

&&

.LONG TERM...
(Saturday through Thursday)
Issued at 1007 PM PDT Thu Jun 27 2024

There`s good global model agreement that a high pressure system will
strengthen approx 1000 miles to the west of the Bay Area by late in
the weekend and Monday. Thereafter, the high is forecast to advance
eastward toward northern California, large scale downward vertical
motion (compressional warming) sending 850 mb temperatures upwards,
EPS/GEFS (27 Celsius) 850 mb temp means are near the max moving
average in comparison to Oakland upper air soundings long term early
July climatology. While recent deterministic output are forecasting
850 mb temps higher, nearing 30C to 31C by July 5th-6th.
With large scale compression, expect the marine layer to do the
same, to be compressed to near sea level, while winds at this time
do not appear to become breezy to gusty offshore; a good idea
however to closely monitor because the global/mesoscale models
sometimes will under-forecast the ACV-SFO gradient (northerly wind)
for example. 850 mb level (~5000 feet) temperatures are a usual
reference point for predicting forecast high temperatures at the
surface since sinking air parcels under a high pressure system will
typically warm dry adiabatically to the surface, daily solar input
connecting with these warmed air parcels, post sunrise temperatures
quickly warming up as a result. Forecast highs expected to warm up
to the 90s/lower 100s, hottest temps Tue-Thu, with likely carryover
of hot temps July 5th-6th. With respect to long term Bay Area
stations record high temperatures for the 4th of July, many still
remain from a 1905 heatwave, including another heatwave early July
1931.

Stay tuned to the latest forecast updates, it`s a good idea to plan
on above normal to well above normal hot temperatures next week. If
the high is slow to move then hot weather will linger to late next
week.

&&

.AVIATION...
(18Z TAFS)
Issued at 1011 AM PDT Fri Jun 28 2024

Widespread VFR returns into the afternoon and lasts into the night.
Winds increase into the afternoon with gusty winds expected at SFO
and along the coast, while other areas stay moderate to breezy.
Winds reduce into the night as IFR/MVFR CIGs move over the coast and
Monterey Bay terminals. These CIGS look to last into late Saturday
morning as widespread moderate to breezy winds build.


Vicinity of SFO...VFR through the TAF period. Expect breezy wot
gusty winds this afternoon with gusts peaking around 24 kts. These
winds last into the evening, reducing, but staying breezy into the
late night. Breezes reduce into early Saturday, but pick up again
that afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Lingering clouds at MRY erode into the
afternoon with VFR expected afterward through the early night.
Moderate to breezy westerly winds build this afternoon, with
slightly stronger winds expected at the immediate coast. Winds
reduce the early night as IFR CIGS move inland and fill over MRY,
with SNS filling later into the night.

&&

.MARINE...
(Today through Wednesday)
Issued at 1011 AM PDT Fri Jun 28 2024

  Breezy to gusty northwest winds continue into the next work week
before reducing to more moderate winds. Significant wave heights
begin to build to 10-12 feet towards the beginning of the next
work week. Light southerly swell continues to move through the
waters alongside moderate northwesterly swell.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Saturday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory from 9 AM Saturday to 9 AM PDT Sunday for
     Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory from 3 PM Saturday to 9 AM PDT Sunday for
     Pigeon Pt to Pt Pinos 10-60 NM-Pt Reyes to Pigeon Pt 0-10
     nm.

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

&&

$$

SHORT TERM...RGass
LONG TERM....Canepa
AVIATION...Murdock
MARINE...Murdock

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