Corral De Tierra, California Weather Forecast Discussion

700
FXUS66 KMTR 251148
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
Issued by National Weather Service Eureka CA
448 AM PDT Thu Sep 25 2025
...New UPDATE, SHORT TERM, LONG TERM, AVIATION, MARINE, FIRE WEATHER...
.KEY MESSAGES...
Updated at 420 AM PDT Thu Sep 25 2025
- Showers and isolated thunderstorms diminishing early this
  morning.
- Isolated thunderstorms possible again this afternoon over
  Mountains of San Benito and Interior Monterey County.
&&
.SHORT TERM...
Issued at 420 AM PDT Thu Sep 25 2025
(Today and tonight)
Very active night across the Bay Area and Central Coast with
numerous showers and thunderstorms. Why the activity? Two words:
cut-of f low. A wound up upper low has been nearly stationary just
west of Monterey Bay. Now for the ingredients: lift, moisture,
and inst ability. Lift can be derived from a weak jet signature
rounding the base of the upper low providing broad ascent.
Numerous vort max es pivoting around the low and areas of PVA are
also assisting the large scale lift. Moisture: latest satellite
drive PWATs show va lues exceeding 1.5 or 175% PON. Those values
arent too far off from ACARs soundings out of SJC earlier in the
evening. Instability:
 Mesoanalysis shows a theta ridge on the east side of the low.
These ridges can sometimes be seen as areas of high moisture and
warm er air - like a fuel zone for thunderstorms. Additionally,
forecast soundings/plots and ACARs data show ok lapse rates, but
more impr essive MUCAPE values.
Weve had numerous weather spotters and general public reporting
thunderstorms. These storms have resulted in brief heavy rain,
gust y winds up to 30 mph, and small hail. Lightning detection
networks have recorded over 3k strikes in the last 12 hours and
over 5k i n the last 24 hours. Most times, this would be a bigger
fire weather concerns, but thankfully these storms are producing
some rain. Given the convective nature and hit or miss precip,
amounts have ranged from a trace to nearly 0.75 inches in the
Santa Cruz Mts.
That being said, until we lose those ingredients showers and
thunderstorms will persist. Current forecast will keep showers and
thu nderstorms around the region through the early part of
Thursday morning. This could easily impact super commuters. Once
the upper lo w begins to slowly move eastward mid morning precip
will end in our area and shift more to the Central Valley. Behind
the low, skies will gradually clear with mild temperatures and
muggy conditions.
Please note, were still experiencing major comms issues and KMUX
is currently limited to just inside the WFO. No ETA on a fix at
this time. Thanks for your patience.
&&
.LONG TERM...
Issued at 420 AM PDT Thu Sep 25 2025
(Friday through Wednesday)
As the upper low shifts south into interior SOCAL by early
Friday, well see a building ridge over the eastern Pacific that
quickly a mplifies over the northern half of California. The
amplified ridge extending south from NORCAL into the Central Coast
will produce a brief warmup on Friday with interior highs around
5-10 degrees above normal. That will push max temps back into the
90s for the hotte st interior locations. The rebuilding marine
layer should keep coastal temperatures right around normal. The
drier weekend will be sh ort lived as the storm door opens back
up. A robust trough takes aim at CA. Longer range guidance brings
rain back to the Bay Area as early as Sunday night/Monday morning
with a marked cold front sweeping through. Still pretty far out,
but there are some signs fo r instability resulting in another
round of thunderstorms. One piece of uncertainty during this time
frame will be the entertainment of a decaying tropical system
Narda. Will Nardas leftovers get pulled in with the trough/cold
front? Time will tell. The EPAC quic kly reloads with additional
frontal passages/rain chances the middle of next for CA. Simply
put, the end of Sept into Oct looks wet. CPC 6-10 day has most of
the region above normal rainfall chances.
&&
.AVIATION...
(12Z TAFS)
Issued at 420 AM PDT Thu Sep 25 2025
Lingering shower and storm chances look to exit the region into
the mid morning. MVFR/IFR CIGs look to affect HAF and the Bays
into the mid morning, but erode in the afternoon. Winds stay
mostly light to moderate through the morning but increase into the
afternoon as cloud cover erodes. Winds reduce again into Thursday
evening as CIGs build along the coast and fill around Monterey
Bay and at OAK. These CIGs begin to erode for HAF and OAK in the
early morning on Friday as a dry airmass builds in to the region.
Vicinity of SFOBreezy winds and shower activity linger into the
mid morning, with MVFR CIGs and lig ht winds expected for the rest
of the morning. CIGS erode into the late morning as moderate to
breez y west winds build. Winds reduce into the evening as
scattered low clouds affect the terminal and fill over OAK. Cloud
cover erodes into early Friday morning as winds become light.
SFO Bridge ApproachSimilar to SFO.
Monterey Bay TerminalsShower and storm activity lingers to the
east of SNS until the late morning. Expect MVFR CIGs to affect the
terminals into the mid morning, but erode into the late morning
as mo derate west winds build. IFR CIGs return in the evening as
winds become light. CIGs at MRY fall to LIFR into the late night.
&&
.MARINE...
(Today through Tuesday)
Issued at 420 AM PDT Thu Sep 25 2025
An upper level low pressure system located near Monterey Bay this
morning will move eastward across the interior this afternoon.
North-northwesterly winds will return and become gusty over the
northern and outer waters later today through Friday. This will
also result in rough and steepening seas. Winds will ease Saturday
and then shift to light southerly on Sunday. A strengthening low
pressure system approaches the Pacific Northwest bringing a cold
front with rain to our coastal waters and bays early next week.
&&
.FIRE WEATHER...
Issued at 420 AM PDT Thu Sep 25 2025
Showers and thunderstorms moved through the district overnight.
Thankfully, most of these storms wer e on the wetter side with
wetting rains. Precipitation will taper off by mid-morning
Thursday. A sl ight warming and drying trend will develop through
Friday. Subtle cooling is expected over the week end with a
redeveloping marine layer. Wet weather returns early next week
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 PM this evening to 9 PM PDT Friday
     for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-
     10 nm.
Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this
     evening for Pt Arena to Pt Reyes 10-60 NM.
Gale Warning from 9 PM this evening to 9 AM PDT Friday for Pt
     Arena to Pt Reyes 10-60 NM.
&&
$$
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NWS MTR Office Area Forecast Discussion