190
FXUS66 KMTR 281123
AFDMTR

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

...New AVIATION...

.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...
(12Z TAFS)
Issued at 423 AM PDT Fri Jun 28 2024

MVFR-IFR ceilings line the immediate coastal region south of the
Golden Gate and extends across the Monterey Bay region and down the
Salinas Valley. Stratus will pare back to the immediate coastal
region later this morning, with breezy onshore winds developing this
afternoon. Stratus is expected to return to the immediate coast and
the Monterey Bay region this evening, with a low to moderate
confidence of development into the SF Bay Area.

Vicinity of SFO...Moderate to high confidence of VFR through the TAF
period. Not expecting stratus to come through the Golden Gate this
morning. West-northwest winds will develop this afternoon and
evening with gusts up to 25 knots. A low to moderate confidence that
stratus flows across the Golden Gate this evening into Saturday
morning.

SFO Bridge Approach...Less confidence in stratus impacts
south of the terminal. Otherwise similar to SFO.

Monterey Bay Terminals...IFR ceilings continue through later this
morning. Breezy onshore winds up to 10-15 knots developing in the
afternoon with IFR ceilings returning early Friday evening.

&&

.MARINE...
(Today through Wednesday)
Issued at 251 AM PDT Fri Jun 28 2024

Fresh to strong northwest winds continue into next week before
easing to become moderate across much of the waters. 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...DialH
MARINE...DialH

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