Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
506 PM PDT Monday Jul 27 2015
..very warm to hot inland temperatures expected from Tuesday
through Thursday of this week....
Synopsis...a significant warm-up is forecast to continue across
inland areas through midweek...and more modest temperature
increases closer to the coast as strong high pressure builds over
the region. Temperatures cool slightly late in the week along
with increased monsoon moisture approaching from the south.
Discussion...as of 03:00 PM PDT Monday...mostly clear skies
prevail across the region this afternoon with inland temperatures
5 to as much as 15 degrees warmer compared to 24 hours ago. This
is a result of a warmer...drier air mass aloft and generally light
surface winds. The weak onshore flow however has held temperatures
into the 60s and 70s near the coast so far this afternoon.
The warming trend will continue through midweek as high pressure
over the southwestern Continental U.S. Builds westward toward California. This
will result in widespread temperatures reaching into the 90s to
around 105 for the warmest inland locations. Meanwhile...the warming
trend will also continue for coastal areas...yet weak onshore flow
should keep coastal temperatures in the 70s to middle 80s. Given the
lack of a stronger offshore flow event...temperatures will drastically
differ from coastal areas to inland locations. Will update the
Special Weather Statement to highlight the very warm to hot inland
temperatures expected for Tuesday and Wednesday. Warm conditions
will continue into Friday...yet temperatures are forecast to cool
slightly with more predominate onshore flow returning and gradual
cooling trend of the air mass aloft.
Late in the week...the forecast models are also showing middle-level
moisture advecting northward across our region on the west side of
the ridge of high pressure. This would bring an increase in middle/high
level clouds and bring a return to somewhat muggy conditions.
Overall...the potential for convection remains low and have kept a
mention out of the forecast with the lack of any middle/upper level
support. It is Worth noting that the GFS model remains the most
bullish with precipitation across the southern and eastern portions
of our region. Meanwhile...the European model (ecmwf) keeps all convection well to
our south and east. Will continue to monitor the forecast guidance
over the coming days to see if they become more consistent with one
another. The medium range models generally maintain dry weather
conditions heading into next week along with temperatures slightly
above seasonal averages.
Aviation...as of 4:50 PM PDT Monday...clear skies will prevail
across the region through the forecast period as a thermal trough
remains positioned along the California coast. Light offshore flow
is expected through midweek as the thermal trough shift west. High
Vicinity of ksfo...VFR conditions will prevail through the
forecast period. A moderate seabreeze will reach 15 to 20 knots this
afternoon with gusts to 25 knots.
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR conditions will prevail through the
forecast period. A moderate seabreeze will reach 10 to 15 knots this
afternoon and may be gusty at times.
Marine...as of 03:00 PM PDT Monday...a broad thermal trough
positioned over California will maintain gusty northerly winds
through this evening. The gusty winds will produce locally steep
wind waves. Winds will decrease tonight and Wednesday as the
thermal trough slides west...relaxing the surface pressure
gradient and improving sea conditions.
... Bay until 9 PM
Small Craft Advisory...mry Bay until 9 PM
Small Craft Advisory...Pigeon pt to pt pinos 0-10 nm until 9 PM
Small Craft Advisory...pt Arena to Pigeon pt 10-60 nm
Small Craft Advisory...pt Arena to pt Reyes 0-10 nm until 3 am
Small Craft Advisory...pt Reyes to Pigeon pt 0-10 nm until 3 am
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm until 3 am
Small Craft Advisory...Pigeon pt to pt Piedras Blancas 10-60 nm until 3 am
Public forecast: rgass
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