355
FXUS66 KMTR 080557
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1057 PM PDT Tue May 7 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 116 PM PDT Tue May 7 2024

A warming trend begins Wednesday as offshore winds develop, with a
Wind Advisory for the interior North Bay on Wednesday morning.
Warmest temperatures are expected Thursday and Friday before a
slight cooldown into the early part of next week.

&&

.UPDATE...
Issued at 946 PM PDT Tue May 7 2024

The short term forecast remains on track. There is some
consideration to broadly reduce the high temperatures on Thursday
and just keep the favorable hot spots where they are. Areas such
as the San Lorenzo Valley may stay the same, but our forecast is
above all GFS and ECMWF ensemble members in several areas of the
North and East Bay. These temperatures will be massaged on the
night shift. The wind forecast is holding on to marginal wind
advisory thresholds and the advisory remains in effect.

&&

.SHORT TERM...
(This evening through Wednesday)
Issued at 116 PM PDT Tue May 7 2024

Clear skies throughout the day today with little to no stratus
development this evening and overnight. High temperatures today
range from the mid 50s to low 60s on the coast, the upper 60s to
lower 70s on the Bayshore, and into the mid to upper 70s in the
interior valleys. Breezy northwest winds will develop this
afternoon, gusting up to 20 to 25 miles per hour in the ridgelines
and passes. Overnight lows will generally range from the mid 40s to
the lower 50s, with some of the most interior regions seeing lows in
the lower 40s.

A warming trend begins Wednesday, with a ridge building over the
northeast Pacific expanding into the Pacific Northwest, interacting
with a piece of an upper level low over the Northern Plains that
regresses over the Rocky Mountains and breaks off into a weak cut-
off low over the Great Basin. The end result is that offshore flow
will start to develop through Wednesday, with the higher elevations
and North Bay being the first to experience the wind shift. A Wind
Advisory is now in effect for the North Bay interior mountains and
valleys from 1 AM to 11 AM on Wednesday, for sustained winds of 20
to 30 miles per hour and gusts up to 45 miles per hour in the higher
elevations. The rest of the region should see wind gusts topping out
around 20 to 25 miles per hour. High temperatures on Wednesday range
from the low to mid 60s along the coast to the upper 70s to lower
80s in the interior valleys.

Despite the breezy offshore winds and the warming trend, very little
fire danger is expected, with moist fuels mitigating fire weather
concerns throughout the region.

&&

.LONG TERM...
(Wednesday night through next Monday)
Issued at 116 PM PDT Tue May 7 2024

The warming trend continues into the early part of the weekend, with
Thursday and Friday expected to be the warmest days of the event.
High temperatures range from the upper 60s to lower 70s near the
coast, to the upper 80s to lower 90s inland. With northeasterly
offshore flow continuing through Thursday, and with prior pattern
recognition of warmer temperatures in downslope areas as a result,
have increased temperatures on Thursday from the previous forecast.
The seasonably warm temperatures are causing a minor to moderate
HeatRisk, meaning that a low to moderate risk for heat related
illnesses exists for vulnerable populations (children, the elderly,
pregnant women, or those without adequate shelter or cooling), with
moderate HeatRisk values concentrated in the interior regions of the
North, East, and South Bays. For some context: downtown San
Francisco, which sees highs around the mid 60s this time of year, is
expected to top out at 81; Santa Rosa, where the seasonal average
high is in the mid 70s, is facing a high temperature of 89; and
Salinas is forecast to reach a high of 80 versus a seasonal average
high of 68.

With the significant warm up expected for the rest of the week,
here`s a reminder of some heat safety tips:

* Stay hydrated and drink plenty of fluids.
* Wear lightweight, light-colored clothing.
* Reduce time spent outdoors or stay in the shade.
* Never leave people or pets unattended in vehicles.
* Use sunscreen if going to the coast or the pool.

The heat should start to abate on Sunday as onshore flow returns to
the region, but temperatures warmer than the seasonal averages are
expected to continue for the foreseeable future, with CPC products
stating that temperatures above seasonal averages continue into the
third week of May.

&&

.AVIATION...
(06Z TAFS)
Issued at 1056 PM PDT Tue May 7 2024

Widespread VFR through the TAF period. With strong and gusty N/NE
winds expected Wednesday afternoon and into the evening, drying of
the lower atmosphere is likely, inhibiting any cloud development.
High confidence in maintaining VFR through the TAF period for all
terminals. N/NE winds will gust Wednesday afternoon to around 20-25
knots, easing slowly into the nighttime hours. However, wind shear
will develop as surface level winds ease but winds aloft remain
elevated.

Vicinity of SFO...VFR through the TAF period. Wind shear develops in
the first hours of Wednesday morning as winds aloft turn to become
more N/NE and strengthen. Through the later morning, these strong
winds aloft will begin to mix down, strengthening surface level
winds and diminishing shear. Come the afternoon, frequent gusts up
to 25 knots are expected. Wind shear returns in the later night of
Wednesday as surface level winds ease, but winds aloft remain strong.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR. Models show just a FEW low clouds
developing off of the Monterey peninsula early Wednesday, but not
expecting a CIG to form. Light winds through the morning
strengthen to become breezy and N/NW in the afternoon of
Wednesday.

&&

.MARINE...
(Tonight through next Monday)
Issued at 1056 PM PDT Tue May 7 2024

Strong northwesterly winds increase into mid week with gale-force
gusts over the outer waters and near Point Sur. Winds gradually
ease into the latter half of the week. As a result of the winds,
wave heights 15 to 16 feet can be expected in the outer waters
through the middle of the week. Wave heights gradually diminish to
around 5 to 7 feet by late week. Dry weather continues through the
forecast period as high pressure dominates.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 11 AM PDT Wednesday for CAZ504-506.

PZ...Small Craft Advisory from 9 AM to 3 PM PDT Wednesday for SF Bay
     N of Bay Bridge.

     Small Craft Advisory until 3 AM PDT Wednesday for Pigeon Pt to
     Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to
     Pigeon Pt 0-10 nm.

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

     Gale Warning until 3 PM PDT Wednesday for Pt Arena to Pt Reyes
     10-60 NM.

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...AC
MARINE...Kennedy

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