Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

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FXUS66 KMTR 300023
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
523 PM PDT Sat Apr 29 2017

.SYNOPSIS...Seasonably warm weekend in place across the Bay Area
and Central Coast. Another round of offshore winds Monday and
Tuesday will drive temperatures even warmer early next week with
daytime highs into the 80s and some lower 90s for the warmest
interior valleys. Cooling trend back to normal by Thursday and
Friday as the next trough arrives on the coast.

&&

.DISCUSSION...as of 2:49 PM PDT Saturday...Decent warming today
across the district under sunny skies and high pressure aloft.
Current temperature readings are running warmer than yesterday at
this time with 60s at the immediate coast, and 70s to lower 80s
inland. Wind speeds have decreased in some areas today, but remain
gusty out of the west in the Salinas valley and at SFO. With
clear skies tonight and decreasing winds, look for overnight lows
to cool into the mid 40s to lower 50s. Similar conditions are
expected on Sunday with perhaps a few degrees of warming under
sunny skies.

A shortwave trough forecast to move into the Great Basin late
Sunday night into Monday morning will increase surface pressure
gradients once again resulting in offshore winds across the hills
early Monday morning and then again Tuesday morning. Warming
aloft with light offshore flow and continued sunny days will
result in possibly the warmest weather so far this spring with
daytime highs well into the 80s and even some lower 90s for the
warmest inland valleys.

A cooling trend is expected to begin on Thursday, at least near
the coast with widespread inland cooling back to near or even
below normal by next Friday as an upper level trough approaches
the west coast. This trough is not expected to bring any rain to
our area, but cooler temperatures and possibly an increase in the
marine layer depth can be expected.

&&

.AVIATION...As of 5:23 PM PDT Saturday...It`s a gorgeous afternoon,
not a cloud to be seen. VFR tonight and Sunday. There is the chance
for patchy coastal low stratus and fog to develop much later tonight,
but confidence in its development is low at this time, will monitor
it through the evening. The ACV-SFO pressure gradient is 5.6 mb and
forecast to reach 7 mb to 8 mb tonight and Sunday as a surface ridge
edges in over far northwestern California. If stratus and fog do
develop it would quite likely either brush the immediate coastline
at times or parallel the coast staying just offshore under a stronger
northerly wind and trapped beneath strengthening marine inversions.

The WMC-SFO gradient will be increasing later Sunday into Monday
morning which may tend to push the surface thermal trough over
interior California to the coast in which case these conditions
would strongly favor VFR to continue from later Sunday into Monday.

Vicinity of KSFO...VFR. Westerly wind gusts to 25 knots til 04z
this evening, lighter winds tonight. Westerly winds become gusty
again Sunday afternoon and evening. Near high confidence.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR. Westerly winds becoming light later
this evening. Boundary layer RHs increase to near 100% very early
Sunday morning along the immediate coastline along the southern
Monterey Bay area to the Carmel Highlands per latest WRF model
run, it may be overdone in tonight`s case, but will monitor it.

&&

.MARINE...as of 01:55 PM PDT Saturday...High pressure will
continue to bring strong, gusty northwest winds to the coastal
waters this afternoon and evening. The strong winds will drive
hazardous seas in the form of steep fresh swells with relatively
short periods. Strong winds will continue through the weekend and
into early part of next week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tngt...SCA...Pigeon Pt to Pt Pinos 0-10 nm until 3 AM
             SCA...Pt Arena to Pt Reyes 0-10 nm
             SCA...Pt Reyes to Pigeon Pt 0-10 nm
             SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
             SCA...Pt Arena to Pigeon Pt 10-60 nm
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
             SCA...Mry Bay until 9 PM

&&

$$

PUBLIC FORECAST: Sims
AVIATION: Canepa
MARINE: Rowe


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