582
FXUS66 KMTR 160523
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1023 PM PDT Sat Jun 15 2024

...New AVIATION...

.SYNOPSIS...
Issued at 1238 PM PDT Sat Jun 15 2024

Dry and windy with elevated fire concerns into early next week.
Seasonal temps and quiet weather midweek. Potential warming trend
for late next week.

&&

.UPDATE...
Issued at 849 PM PDT Sat Jun 15 2024

Temperatures this afternoon were actually slightly WARMER that
yesterday as northerly flow increased and sunny sky conditions
prevailed. Overnight low temperatures are expected to cool into the
upper 40`s to low 50`s for most areas while slightly warmer in the
hills and higher terrain. Tomorrow, expect similar temperatures as
today with 80`s across the interior, 70`s just inland away from the
coast, and 60`s near the coast. RH values again are expected to drop
into the teens and twenties across the interior tomorrow afternoon
while onshore flow keeps more moist conditions near the coast. A
wildfire started in San Benito County this afternoon and last
reported at 400 acres and 20% contained - Hernandez Fire. Again, be
mindful and don`t be "that spark". The ongoing forecast remains on
track with no updates expected at this time.

&&

.SHORT TERM...
(This evening through Sunday)
Issued at 1238 PM PDT Sat Jun 15 2024

Clear skies continue into the evening with drier conditions compared
to yesterday evening. N-S gradient continues to strengthen bringing
some occasional gusty strong winds, especially over the hills,
coastal gaps, and mountain ranges, into the late evening. The winds
will mostly have impacts over our marine zones where winds can reach
up to 45-55 mph, especially along the Big Sur coast. With this
strong gradient and drier air conditions, clouds will remain mixed
out going into Sunday, giving us a break from the June-Gloom. With
the clear skies, expect a few degrees lower tonight, compared to
last night as radiative cooling goes into effect. Minimum
temperatures will get down to mid 40s to mid 50s across the region.
As we low pressure system off the Pacific NE move closer inland
and sit over Washington and Oregon state on Sunday, expect another
day of cooler temperatures. Inland areas are looking to see high
70s to low 80s, with the coastline seeing max temperatures in the
60s. Strong northerly winds will also support cooler temperatures
going into Sunday.

&&

.LONG TERM...
(Sunday night through next Friday)
Issued at 1238 PM PDT Sat Jun 15 2024

As we move into the beginning of the work week, we will start to see
that low pressure system gradually dip down even further into our
area, allowing for some strong gusty winds to persist Sunday into
Monday. This does bring some fire concerns as the minimum relative
humidity values are expected to get down to the teens in certain
parts of the region. Although there are some areas in our region
that bring elevated fire concerns, no RFW have been issued as the
overall conditions have not met warning criteria for our area at
this moment. Fire conditions will be closely monitored, especially
if the north/northeast winds linger and low relative humidity
continues beyond Monday afternoon. (See Fire Weather discussion
below for more details)

As we move into Tuesday, we will start to see the N-S gradients to
gradually decrease as the upper level pattern start to transition
into a zonal/weak ridging pattern. This will bring a warming trend
starting Thursday with temperatures in the upper 80s and 90s going
into the weekend with some chances of triple digit values. CPC and
WPC outlooks also show portions of our area for excessive heat with
a 50-60% above normal temperatures.

&&

.AVIATION...
(06Z TAFS)
Issued at 1023 PM PDT Sat Jun 15 2024

VFR conditions throughout the region, generally through the TAF
period. Model output has some probability of stratus development
tonight at the immediate coast and the Monterey Bay region, but
confidence is low and strong winds aloft may keep the skies clear
through the night. Northwest winds will abate at the terminals, but
will remain breezy through the night before strong northwest winds
with gusts up to 20 to 30 knots resume Sunday afternoon. Marginal
LLWS concerns will develop on Sunday evening along the coastal
ranges as the surface layer decouples, but confidence is too low to
include it in the TAFs.

Vicinity of SFO... VFR through the TAF period. West-northwest winds
will remain breezy and gusty overnight with intense gusts returning
on Sunday afternoon. Moderate confidence that gusts at SFO will
exceed 35 knots sometime on Sunday. Additional TAF updates will take
newer model cguidance into account. Marginal LLWS concerns develop
on Sunday evening close to the end of the TAF period.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... Model output shows some probability of IFR
ceilings developing in the region later tonight, but confidence is
low and the TAFs remain VFR throughout. Onshore winds will remain
breezy through the night before becoming strong on Sunday afternoon
with gusts up to 20-25 knots.
&&

.MARINE...
(Tonight through next Friday)
Issued at 849 PM PDT Sat Jun 15 2024

A tight pressure gradient over the waters continues to allow for
strong northwest breezes and widespread gale force gusts to
persist through the weekend. Significant wave heights will reach
12-17 feet through the weekend before beginning to decrease
Monday. Hazardous conditions will linger into the first half of
next week as winds remain strong.

&&

.FIRE WEATHER...
Issued at 345 AM PDT Sat Jun 14 2024

...Elevated Fire Weather Conditions Through The Weekend...

*Increasing northerly winds, especially higher terrain
*Lowering relative humidity values day and night

Forecast remains on track as northerly flow ramps up across the
district. Gusts of 30-50 mph will be more common along the coast,
higher terrain, and inland gaps/passes. Have already seen a few
isolated inland passes reach close to 60 mph as well. These
stronger winds will persist through early Monday. It should be
noted that they will not be strong the entire time, more like
bursts of stronger winds. The northerly flow has also ushered in
much drier air across the region too. 24 hour trends show some
locations 40-70% drier than 24 hours ago. While there are a few
isolated stations that may "technically" reach Red Flag criteria
conditions are not widespread enough to warrant a fire weather
zone wide Red Flag warning. Therefore, still best to message
elevated fire weather conditions through the weekend.

Regardless, individuals with outdoor activities planned this
weekend should be fire weather aware. Be mindful and don`t be
"that spark".

MM

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM Sunday to 3 AM PDT Monday for SF
     Bay N of Bay Bridge.

     Small Craft Advisory until 3 AM PDT Monday for Mry Bay.

     Gale Warning until 3 AM PDT Monday for Pigeon Pt to Pt Pinos 0-
     10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-
     10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras
     Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

&&

$$

SHORT TERM...SO
LONG TERM....SO
AVIATION...DialH
MARINE...DialH

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