568
FXUS66 KMTR 201924
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1224 PM PDT Mon May 20 2024

...New SYNOPSIS, SHORT TERM, LONG TERM...

.SYNOPSIS...
Issued at 1224 PM PDT Mon May 20 2024

Typical summer-like pattern to persist throughout the first half of
the week. Temperatures are forecast to dip below seasonal averages
by the upcoming weekend as an upper level trough impacts the
region.

&&

.SHORT TERM...
(This evening through Tuesday)
Issued at 1224 PM PDT Mon May 20 2024

Weak offshore flow aloft is resulting in dry weather conditions this
afternoon with minimum relative humidity values between 15-35% for
inland areas and those higher up in elevation. Meanwhile, the coast
continues to experience onshore flow with higher humidity. Humidity
increases overnight in all but the highest elevations with lows
generally in the mid-to-upper 40`s to low-to-mid 50`s.

RH values will be even lower tomorrow as offshore flow aloft
persists and will drive drier conditions even closer to the coast.
As such, tomorrow will be the warmest day of the week with mid 80`s
across the interior and 60`s to lower 70`s near the coast. People
who are incredibly sensitive to heat should take precautions while
outdoors and remember to drink plenty of water.

&&

.LONG TERM...
(Tuesday night through next Sunday)
Issued at 1224 PM PDT Mon May 20 2024

By late week, temperatures cool to near seasonal averages across the
interior but coastal locations will still be slightly cooler due to
onshore flow. By this upcoming weekend, temperatures region-wide
drop below average as a mid/upper level trough more directly impacts
the region. This systems looks fairly dry with ensemble guidance
indicating very low chances of accumulating precipitation with it
Friday into Saturday morning. If any precipitation does fall it will
be light and not very impactful. Guidance from the Climate
Prediction Center indicates slightly below average temperatures and
slightly above average precipitation through the end of the month.

&&

.AVIATION...
(18Z TAFS)
Issued at 1035 AM PDT Mon May 20 2024

MVFR stratus is clearing across the Central Coast valleys and will
completely mix out later this morning. Breezy and gusty onshore
winds will develop in the afternoon, with the gusts generally up to
20 knots at the terminals. Generally VFR conditions for the interior
through the night, with moderate confidence (40-60% probability) of
patchy MVFR stratus developing early Tuesday morning around
Monterey Bay and a lower confidence (10-20% probability) of
further development elsewhere on the coast south of the Golden
Gate.

Vicinity of SFO... VFR through the TAF period. Breezy and gusty west-
northwest winds with gusts up to 25-28 knots developing later this
afternoon, diminishing in the evening and resuming Tuesday
afternoon. Probability of gusts above 35 knots is near zero.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... MVFR stratus will clear out later this
morning. Breezy northwest winds will develop in the afternoon and
diminish in the evening. Model output shows a moderate confidence
(40-60% probability) of some patchy MVFR stratus around the region
early Tuesday morning, with the period of highest probability from
10-16Z. Probabilities for stratus are higher in the area north of
MRY and south of WVI.

&&

.MARINE...
(Today through Saturday)
Issued at 907 AM PDT Mon May 20 2024

Strong and gusty northwest winds persist over the coastal waters
through Thursday. Expect hazardous conditions and steeper wind
waves during the week. Winds look to ease later in the week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Wednesday for Pt Arena to Pt
     Reyes 0-10 nm.

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

     Small Craft Advisory from 3 PM Tuesday to 3 AM PDT Wednesday for
     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 Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...DialH
MARINE...DialH

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