Scientific Forecaster Discussion
fxus66 kmtr 210408
Area forecast discussion
National Weather Service San Francisco Bay area
908 PM PDT Fri Jul 20 2018
Synopsis...dry conditions and seasonably warm daytime
temperatures will prevail through the weekend with marine air
keeping conditions cooler near the coast. A more robust warming
trend is then expected for next week, especially across inland
areas, as as strong ridge of high pressure builds over the region.
Discussion...as of 9:08 PM PDT Friday...the upper-level ridge,
responsible for the very warm/hot inland temperatures yesterday,
shifted eastward over Texas and the southern Great Plains today,
relieving most of the triple digit heat that was felt yesterday
afternoon across interior portions of the County Warning Area. Today's high
temperatures ended up being closer to seasonal normal, in general,
with mainly 70s near the coast to 90s inland. The last viewable images
of this evening's visible satellite shows stratus hugging the
coastline, already penetrating through the Golden Gate gap, as
well as Monterey peninsula/northern part of the Salinas valley.
No major updates were made to the forecast since this afternoon.
However, did add a chance of patchy fog & drizzle for the entire
coastline and parts of the East Bay through mid morning Saturday
after already receiving some reports of drizzle. Otherwise,
Saturday, and the weekend in general look to be very similar to
today. Temperatures will hover around seasonal average, ranging
from upper 60s/lower 70s near the coast to widespread 80s and 90s
inland. The marine layer should continue to hold at a depth
around 1,500 feet, give/take, with stratus penetrating the typical
coastal spots each evening & morning.
The hot weather will be the main storyline for much of California
over for the mid-long range forecast. The aforementioned upper-
level ridge is forecast to retrograde back westward early next
week, with 500mb heights approaching 600 dam over Arizona &
Southern California by the end of the week. At this time, it
appears far inland locations will be most impacted by the strong
ridge. Coastal and near coastal locations should see a decent
onshore seabreeze push during the afternoons, limiting daytime
heating. As for far inland locations, long-range forecast models
are currently producing temperatures potentially reaching 105-110f
in some of the typical hot spots, I.E., In areas of southern
Monterey and San Benito counties. Of course, this will continued
to be monitored and updated through the weekend and into early
Aviation...as of 5:15 PM PDT Friday...conditions late Friday
afternoon were similar to Thursday afternoon with moderate onshore
flow and a marine layer depth of about 1500 feet. IFR ceilings
had already developed at kmry and ksns by 00z and expect IFR
ceilings to also develop at ksts and koak by 06-08z. Ksjc and klvk
likely to remain VFR overnight. Ksfo likely to remain VFR
overnight due to southerly flow over Santa Cruz Mountains, but
some forecast uncertainty for ksfo.
Vicinity of ksfo...VFR through the period, but forecast
confidence only moderate as IFR conditions likely to develop to
the north and east of ksfo overnight. Light westerly winds.
Sfo bridge approach...similar to ksfo.
Monterey Bay terminals...IFR ceilings until about 17z Saturday
morning then VFR likely. Light southwest winds.
Marine...as of 8:43 PM PDT Friday...light southerly winds are
forecast across most of the coastal waters through midday Sunday.
Winds will turn to the west and northwest on Sunday afternoon.
Northwest winds are then forecast to increase through much of next
week. A long period southwesterly swell will arrive by early next
... Bay until 9 PM
Small Craft Advisory...pt Arena to Pigeon pt 10-60 nm until 9 PM
Public forecast: BAM
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