Mount Saint Helena Golf Course California Weather Forecast Discussion

125
FXUS66 KMTR 142012
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
112 PM PDT Tue Oct 14 2025
...New SHORT TERM, LONG TERM...
.KEY MESSAGES...
Updated at 1228 PM PDT Tue Oct 14 2025
- Scattered showers continue this afternoon and evening,
   localized downpours and hail possible.
- Warming and drying trend Wednesday through Saturday.
- Unsettled weather returns Sunday
&&
.SHORT TERM...
Issued at 1228 PM PDT Tue Oct 14 2025
(This evening through Wednesday)
The 12Z sounding found very cold air aloft. The 850 temp was 2.35C
and 500 temp -25.35C. Both near the minimum daily values. Most
notable was the 500 mb height of 5460m. That shattered the daily
record. For context the average for this date is 5787, 10th
percentile: 5667, old record: 5572. In fact, 5460 is tied for the
second lowest 500 mb height ever measured in the month of October,
beaten only by 5457m measured on 10/28/56. While this cold air is
keeping lapse rates steep, the moisture has plummeted and the surface
front has passed into southern California keeping the impacts much
lower today. That being said, there are still scattered showers
expected through the evening. Some of these could be strong with
possible lightning, hail and brief downpours. By Wednesday the
atmosphere will restabilize and the chance for rain will drop to
near zero. The wet soil, combined with clearing skies tonight and
cool temperatures will bring a chance for fog Wednesday morning if
a shallow inversion forms.
&&
.LONG TERM...
Issued at 1228 PM PDT Tue Oct 14 2025
(Wednesday night through next Monday)
Over the next several days the bowling ball mid level low will
fill and move NE, returning back to the jet stream over the
central US. While this happens, ridging from the subtropical high
will nudge in over California. This will kick off a warming trend
starting Wednesday, with temperatures returning to comfortable
seasonal average by Friday. Saturday will be a few degrees warmer
than normal before the pattern breaks down. A new, more typical
trough is set to approach the coast by Sunday, bringing a slight
cool down into early next week. Ensemble cluster analysis suggest
there is a good amount of uncertainty regarding how deep this
trough gets, complicated in part by a left-over cutoff low off the
coast of Mexico. If these 2 features combine there is a chance
for rain, otherwise the trough likely won`t be deep enough to
bring more than clouds and cooler weather.
&&
.AVIATION...
(18Z TAFS)
Issued at 1056 AM PDT Tue Oct 14 2025
Deep upper low pressure system currently located off the Central
Coast will continue to meander towards the southeast. Mixed skies
thru today with SCT Cu and stratus. Light rainfall and shower
activity anticipated for North Bay terminals through the early
afternoon, migrating to the East Bay region by the early evening.
Patchy MVFR cigs anticipated tonight as temps cool and showers
end. High confidence in clearing skies from west to east by the
sunrise hour Wednesday.
Vicinity of SFO...VFR thru most of the period with the exception
of the overnight hours where cigs may lower to MVFR. Any cigs that
do develop will likely scatter out by sunrise Wednesday. Most
shower activity expected to remain east of the terminal and
approach. However, keeping VCSH in forecast with the best chance
00-03Z. VFR thru Wednesday with isolated SCT/BKN Cu.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Mostly clear today with SCT Cu being the
biggest factor. Low chance of isolated showers this afternoon.
Moderate confidence in VFR thru the rest of the period. Once
again, biggest impact Wednesday will be SCT/BKN Cu moving off high
terrain.
&&
.MARINE...
(Today through Sunday)
Issued at 1056 AM PDT Tue Oct 14 2025
Surface low currently centered near Point Sur will promote
isolated showers across the waters today. Cannot rule out an
isolated thunderstorm south of Pigeon Point through this
afternoon. Hazardous seas will persist with seas over 10 feet over
the outer waters. Overall conditions will gradually improve late
Tuesday into Wednesday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 PM PDT this afternoon for Pigeon Pt
     to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM.
&&
$$
SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...Behringer
MARINE...Behringer
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NWS MTR Office Area Forecast Discussion