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

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FXUS66 KMTR 240547
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
1047 PM PDT SAT JUL 23 2016

.SYNOPSIS...Slightly cooler temperatures are forecast for inland
areas on Sunday and Monday as high pressure over California
weakens slightly. Warming is then forecast for Tuesday and
Wednesday before a gradual cooling trend takes over late in the
week and into next weekend.

&&

.DISCUSSION...As of 8:55 PM PDT Saturday...Temperatures at some
locations near the ocean were cooler today compared to Friday. But
for the rest of our region, highs today were warmer by about five
degrees. And, today`s high temperatures were warmer than normal
almost everywhere.

The strong upper ridge that currently dominates the southwestern
United States is forecast to weaken slightly over California
during the next two days. In addition, robust north-to-south
surface pressure gradients will gradually weaken, causing moderate
northerly low level flow to turn light southerly by Monday. These
changes will result in cooler temperatures, especially inland, on
Sunday and Monday. The most significant cooling is expected in the
North Bay Valleys where highs by Monday are expected be as much
as 12 degrees cooler than today`s highs.

The models agree that the ridge will strengthen over California
once again on Tuesday and Wednesday and we will see temperatures
warm above normal in all areas. Even coastal areas are expected to
see modest warming on those two days as onshore flow weakens. By
midweek look for the warmest inland valleys to once again reach
100 or a bit higher.

In the longer range the general idea is for cooling by next
weekend. The GFS forecasts the cooling trend to begin late in the
work week and then become more pronounced next weekend as the
ridge moves off to the east and an upper trough begins to develop
near the West Coast. However, the ECMWF maintains the ridge`s
strength over California through at least the end of the work week
(and thus very warm inland temperatures) and doesn`t initiate
cooling until the weekend arrives.

&&

.Fire...As 9:30 AM PDT Saturday...High pressure persists over
California today and has compressed the marine layer to around
1000 feet deep this morning. The marine layer is expected to
remain compressed to at or below a 1000 feet tonight. In addition,
a temperature inversion is anticipated to set up overnight
maintaining warm overnight temperatures over areas of higher
terrain. Overnight temperatures at 2000 feet will be in the mid to
upper 70s with poor relative humidity recoveries.

&&

.AVIATION...as of 10:45 PM PDT Saturday...Stratus has cleared out
this evening. But stratus is expected to reform along the coast
later tonight due to nighttime cooling. Cigs will also spread
into the MRY Bay Area as well after 12z. It is looking less likely
that there will be cigs in the SFO Bay Area as the ACV-SFO gradient
is still 6 MB. Patchy clouds should form late as the gradients
slacken.

Vicinity of KSFO...VFR.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...IFR cigs return to MRY and SNS after
09Z.

&&

.MARINE...as of 10:45 PM PDT Saturday...High pressure will
continue off the California coast through next week. A thermal
trough will shift to the coast on Sunday. This will result in
decreasing winds over the inner waters on Sunday and the southern
outer waters on Monday. Strong winds will continue over the
northern outer waters.

&&

.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 Arena to Pigeon Pt 10-60 nm
             SCA...Pt Reyes to Pigeon Pt 0-10 nm
             SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm

&&

$$

PUBLIC FORECAST: Dykema
AVIATION: W Pi
MARINE: W Pi


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