National Weather Service Raw Text Product

368 
FXUS66 KMTR 300554
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
1054 PM PDT Sat Apr 29 2017

.SYNOPSIS...Sunny and seasonably warm weather will continue across
our region through the remainder of the weekend. Another round of
offshore winds is forecast during the first half of the work week,  
which will push temperatures even warmer from Monday through
Wednesday. A cooling trend is then forecast next Thursday and 
Friday as the upper ridge over California is replaced by a trough.

&&

.DISCUSSION...As of 8:55 PM PDT Saturday...A building upper ridge
offshore brought a warmer and drier airmass into our region today.
Highs today were 5 to 10 degrees warmer than yesterday and ranged
from the 70s to lower 80s in most locations, values that were
about 10 degrees warmer than normal.

The upper ridge centered offshore along 135W is forecast to
continue edging slowly to the east for the remainder of the
weekend, and the airmass aloft over our area is expected to 
continue to warm. However, surface gradients have turned slightly
onshore this evening and the incoming marine air will probably
offset the overall airmass warming under the ridge. The net result
for temperatures tomorrow will likely be persistence. The upshot
is that Sunday will probably be a day much like today. Although 
light onshore flow has developed this evening, the boundary layer 
remains very dry and it's unlikely there will be any coastal fog 
or low cloud development.

Surface high pressure is forecast to strengthen to our north and
east by late Sunday night. This will set the stage for another
round of offshore flow across our region from late Sunday night 
through midweek. Gusty north winds are likely in the hills from 
late Sunday night through Tuesday night, mainly during the late 
night and morning hours when local gusts up to 30 mph are 
possible. This offshore flow will bring a drier airmass into our
area once again. At the same time, the upper ridge offshore will 
gradually shift inland, warming the airmass over our area further.
850 mb temperatures, which were at 12 degrees C over OAK today, 
are forecast to climb as high as 19 C by Wednesday. These 
developments will result in a warming trend during the first half 
of the work week with widespread 80s expected by Tuesday and 
Wednesday and a few lower 90s likely in the warmest inland areas. 
Coastal areas will mostly see high temperatures in the 70s, but 
lower 80s are possible in San Francisco, especially on Wednesday. 
Temperatures during the first half of the week will be the 
warmest of the year so far.

The models agree that that an upper trough will approach the West
Coast later in the week, resulting in robust cooling on Thursday
and Friday. 

&&

.AVIATION...As of 10:54 PM PDT Saturday...VFR tonight and Sunday.
The ACV-SFO pressure gradient is forecast to reach 7 mb to 8 mb 
tonight and Sunday as a surface ridge edges in over far northwestern
California. Any patchy stratus and fog that develops will quite 
likely either brush the immediate coastline at times or parallel 
the coast staying just offshore under a strong northerly wind and
trapped beneath strengthening and compressed 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. Lighter westerly wind tonight. Westerly 
winds become gusty again Sunday afternoon and evening. Near high 
confidence.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR. Mainly light westerly winds tonight.

&&

.MARINE...As of 8:50 PM PDT Saturday...High pressure will 
continue to bring strong, gusty northwest winds to the coastal 
waters this 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

&&

$$

PUBLIC FORECAST: Dykema
AVIATION: Canepa
MARINE: Canepa/Rowe


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