Corte Madera School California Weather Forecast Discussion

340
FXUS66 KMTR 150104
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
604 PM PDT Tue Oct 14 2025
...New AVIATION, MARINE...
.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...
(00Z TAFS)
Issued at 604 PM PDT Tue Oct 14 2025
VFR-MVFR with scattered showers and patchy fog /LIFR-IFR/ tonight
and Wednesday morning. Dry weather and VFR Wednesday.
Vicinity of SFO...VFR-MVFR. A few showers in the vicinity otherwise
drier conditions Wednesday. West wind near 10 knots decreasing to
light and variable wind tonight and Wednesday morning. West to
northwest wind 5 to 10 knots late Wednesday afternoon and evening.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR-MVFR. A few showers in the vicinity
otherwise drier conditions Wednesday. Mainly onshore winds 5 to 10
knots becoming southeast winds 5 to 10 knots tonight and Wednesday
morning. Onshore winds near 10 knots redeveloping Wednesday
afternoon.
&&
.MARINE...
(Tonight through next Monday)
Issued at 558 PM PDT Tue Oct 14 2025
Low pressure and cold air aloft will result in a few additional
showers across the waters through sunset. Otherwise dry northerly
winds will return to the waters tonight through the weekend.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...Canepa
MARINE...Canepa
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NWS MTR Office Area Forecast Discussion