deformed-offering

NWS Forecast Area Discussion - San Francisco Area

000
FXUS66 KMTR 231147
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
447 AM PDT Wed Aug 23 2017

.SYNOPSIS...Look for a couple more days of normal to a bit below
normal temperatures across our region. A ridge of high pressure
will build toward our region starting on Friday which will lead to
a warming trend.

&&

.DISCUSSION...as of 3:15 AM PDT Wednesday...Much more straight-
forward satellite image this morning compared to yesterday! With a
marine layer around 1,200 feet plus a west-to-east surface
gradient over 2 MB clouds are across all coastal locations plus
the vast majority of valley spots. Worth noting that the marine
layer has slightly compressed over the past few hours, so will
need to see if that trend continues. Regardless, clouds will burn-
off toward the coast later this morning. Highs will be close to
normal to slightly below normal with 60s and 70s at the coast
while upper 70s to around 90 will be common inland. Tomorrow will
be a near repeat, although if the marine layer continues to
compress there will be fewer clouds Thursday morning.

Synoptically the upper level low currently overhead will dissipate
and head off well to the south. At the same time a ridge of high
pressure will start to build into our region from the Four Corners
area. This will lead to a further compression of the marine layer
along with a warming trend. 850 MB temps will soar to 25-27C by
next week while 500 MB heights will near 593 DM. Both of these
values are lower than record numbers for the month, however they are
on the upper end of the chart. Temperatures will see a nice
increase with inland spots returning to the upper 80s to lower
100s degree range in many spots. Isolated reports of 103 to to 107
can be expected although those will mostly be in spots that are
sparsely populated. At the coast widespread upper 60s to lower 80s
are likely.

Longer range guidance favors warmer than normal readings
continuing all the way through the end of next week.

&&

.AVIATION...As of 4:43 AM PDT Wednesday...For 12z TAFs. Satellite
looks more typical this morning for this time of the year than 24
hours ago. A mixed bag of flight categories across the district,
as stratus has pushed into most taf sites under a 1500 ft marine
layer. These cigs are expected to continue through about 16-17z.
Onshore flow will prevail through the afternoon hours, 10-15 kt,
with higher wind speeds likely at KSFO. KSTS will see generally
light to moderate southerly winds today.

Vicinity of KSFO...Borderline IFR-MVFR cigs through about 16-17z,
then VFR. Light to moderate westerly winds by early afternoon,
around 15 kt. Stratus anticipated to return late tonight.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...LIFR/IFR cigs through about 17z, with low
confidence on exact timing of clearing for KMRY. Light to moderate
west winds this afternoon, 10-15 kt.

&&

.MARINE...as of 02:54 AM PDT Wednesday...Northerly winds will
increase from north to south beginning later this morning as high
pressure builds in from the west and  interacts with coastal
troughing. Steep fresh northwest swell will occur as a result of
the increasing winds. No significant long  period swell through
the rest of the week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tday...SCA...Pt Arena to Pt Reyes 0-10 nm from 10 AM
             SCA...Pt Arena to Pigeon Pt 10-60 nm from 10 AM
             SCA...SF Bay from 10 AM

&&

$$

PUBLIC FORECAST: Bell
AVIATION: BAM
MARINE: BAM


Visit us at www.weather.gov/sanfrancisco

Follow us on Facebook, twitter, and youtube at:
www.Facebook.com/nwsbayarea
www.twitter.com/nwsbayarea
www.youtube.com/nwsbayarea

NWS MTR Office Area Forecast Discussion

deformed-offering