FXUS66 KMTR 290556
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1056 PM PDT Mon Oct 28 2024
...New AVIATION, MARINE...
.SYNOPSIS...
Issued at 1228 PM PDT Mon Oct 28 2024
An active weather pattern will bring cold weather through the week
with periods of rain and strong wind.
&&
.UPDATE...
Issued at 725 PM PDT Mon Oct 28 2024
Only a couple of rain showers on radar in Eastern Napa County and
Eastern Contra Costa County with rain shower activity continuing
to diminish as daytime heating is lost. The main hazard in the
short term will be the cold. Tonight will be the coldest night
this week as strong and gusty northwesterly winds continue through
the morning and clear skies allow for radiational cooling. The
forecast remains on track with no necessary changes needed at this
time.
&&
.SHORT TERM...
(This evening through Tuesday)
Issued at 1228 PM PDT Mon Oct 28 2024
KMUX is back online, and just in time to watch the surface based
convection develop into the afternoon. Showers are currently
isolated, but coverage is gradually increasing as the surface
continues to warm. Some returns have touched the 50 dBz threshold,
though not over any rain gauges yet, so there's still some
uncertainty regarding how much is actually hitting the ground.
The latest HRRR runs shows surface based CAPE of 200-400 J/kg,
peaking in the early afternoon, and we have surpassed the
convective temperature of 64F at Oakland. This means there is a
good amount of low-level instability. The limiting factors are a
0.64" PWAT, and elevated inversion at 700 mb. Most of the cloud
layer is below the freezing level, and lightning is still very
unlikely.
A coastal jet is expected to develop this evening, bringing strong
winds to the coast and SF Bay. Sustained winds of 20 mph with
gusts up to 35 mph are expected. Storms will peter out through
the night as the skies clear. This, combined with the strong
northerly winds, will allow the temperature to rapidly drop
overnight. Tuesday morning will bring some of the coldest
temperatures seen since May. Other than the cold, the skies will
be clear and winds decreasing. This is the only guaranteed dry day
through the week. Perhaps a good day for the procrastinators to
visit to the pumpkin patch.
&&
.LONG TERM...
(Tuesday night through next Sunday)
Issued at 1228 PM PDT Mon Oct 28 2024
Colder than normal temperatures will continue through Saturday.
A reinforcing trough moves through the Pacific Northwest,
renewing rain chances from late Wednesday through Thursday. The
probability of precipitation is high for this next event, but the
moisture plume will move through fast, and the overall
accumulation is still around 1/10"-1/4", again focused north of
the Golden Gate. A 3rd system will move through on Friday-Saturday,
bringing yet another chance for rain. There is still a lot of
uncertainty regarding this system, but the coverage looks more
widespread.
By Sunday, 500 mb cluster analysis shows a 75% chance for another
inside slider type pattern with a cut-off low pressure system over
the SW. This would flip the switch back to warm, dry, offshore
winds. Some guidance suggests this new pattern could last well
into next week. While it's too early to figure out the specifics,
it's a good reminder that despite the chilly weather this week,
fire season is not over.
&&
.AVIATION...
(06Z TAFS)
Issued at 1055 PM PDT Mon Oct 28 2024
High confidence that VFR will persist over the region overnight with
brief MVFR conditions over the Monterey Bay region (20-30% chance).
Breezy and gusty westerly winds will continue to ease with light to
moderate winds expected through the overnight. Onshore winds
increase by late Tuesday morning and will remain gusty at times
throughout the afternoon.
Vicinity of SFO...VFR, high confidence. Winds will diminish to
moderate overnight but will rebuild to breezy by Tuesday afternoon.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Mostly VFR but a MVFR ceiling has developed
over KMRY with a TEMPO in to cover this in the short term. Moderate
confidence on VFR prevailing through the TAF period, as upper air
conditions should remain on the dry side.
&&
.MARINE...
(Tonight through next Sunday)
Issued at 1055 PM PDT Mon Oct 28 2024
A fresh NW breeze and rough seas up to 12 feet across the marine
zones continue. Winds will increase to a strong NNW breeze
overnight before decreasing through the day Tuesday but seas will
diminish Tuesday night into Wednesday. Another cold front will
move through Wednesday night, increasing winds back to a fresh NW
breeze and rebuilding rough seas through the day Thursday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Tuesday for Mry Bay-SF Bay N
of Bay Bridge.
Small Craft Advisory until 9 AM PDT Tuesday for Pt Arena to Pt
Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory until 9 PM PDT Tuesday for Pigeon Pt to Pt
Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Pinos to Pt
Piedras Blancas 0-10 nm.
Small Craft Advisory until 3 PM PDT Tuesday for Pt Arena to Pt
Reyes 10-60 NM.
&&
$$
SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...RGass
MARINE...SO
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
Prepared by Boulder-Creek.com Weather at: Tue Oct 29 00:30:03 PDT 2024
From the National Weather Service
|