Rohnert Park, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

098
FXUS66 KMTR 211954
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1254 PM PDT Wed May 21 2025

...New SYNOPSIS, SHORT TERM, LONG TERM, FIRE WEATHER...

.SYNOPSIS...
Issued at 1252 PM PDT Wed May 21 2025

Dry and warm conditions will prevail the rest of today and through
tonight. Gusty winds and drying grasses will maintain heightened
fire weather concerns for grass fire through Thursday. Near normal
temperatures for Thursday.

&&

.SHORT TERM...
(This evening through Thursday)
Issued at 1252 PM PDT Wed May 21 2025

Weak high pressure over the area is helping to maintain warmer
than normal temperatures for today. This associated with dry
conditions has limited cloud cover over the region. This morning
there was a shallow cloud layer over Monterey Bay and down through
the Salinas Valley. Otherwise most areas have remained and
continued to remain clear. Despite the lack of clouds over a large
portion of our service area, the marine layer was in place and
easy to see looking at the coastal profilers and max RH from this
morning. Many areas were well north of 60 percent RH at max.
However, all one needs to do it trek above about 800-1000 feet and
the max RH from this morning was in the 40 percent range. This
pattern will remain in place for tonight as well, with the top of
the moist layer at about 800 feet. High pressure may even suppress
it down a little farther allowing for more prevalent mid value
RHs. Wind will be the big factor. An upper level low with a weak
surface reflection is moving towards the west coast, which mean a
tightening pressure gradient between the approaching low and the
high pressure over land. This will provide a solid environment for
increasing onshore winds. The main impacts from these increasing
wind gusts will be along the immediate west facing coastline and
area mountains and ridges. Gusts will continue to build overnight,
peaking in the AM hours of Thursday. Place such as Altamont Pass
could see some peak gusts from the west to around 40 mph.

Thursday will bring a slight cooling as temps start to be impacted
by the approaching cold front. Look for near normal temps for
Thursday. Winds will remain up for early Thursday, then abate in
the afternoon becoming more normal for this time of year.

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 1252 PM PDT Wed May 21 2025

Broad troughing will dominate Thursday night into Friday ushering
in a cooler and moist air mass. Expect temps to be up to 10
degrees below normal. This trough will help to deepen the marine
layer allowing for more moisture to intrude inland and make its
way up the hills. Expect more cloud cover Friday and Saturday
mornings than what has been seen over the last few days. By the
time we get into memorial day weekend, a dirty ridge will try to
establish over the area, but will be challenged to clear out the
morning low clouds and raise temps to the above normal range.
Thus, for Saturday and most of Sunday, expect near normal
conditions with morning clouds, afternoon sun, and temps in the
60s and 70s. By Monday models are leaning towards a deep trough
with a surface cold front reflection, approaching the coast. This
will bring more clouds, onshore winds, and cooler air advecting
into the area. This pattern will stick around into Tuesday. For
now, expect a cool cloudy start to the workweek.

&&

.AVIATION...
(18Z TAFS)
Issued at 1023 AM PDT Wed May 21 2025

VFR conditions have returned all TAF sites and look to persist
through the remainder of the afternoon and evening. Onshore winds
will increase by late morning or early afternoon before easing into
the night. There is moderate confidence for low clouds to return to
the Monterey Bay terminals early Thursday morning. Elsewhere, VFR
conditions are likely to persist through the TAF period.

Vicinity of SFO...Onshore winds are forecast to increase this
afternoon with gusts up to 30 kt. Winds are forecast to ease into
the night potentially becoming variable early Thursday morning.
Onshore winds will return by Thursday afternoon. VFR conditions are
likely through the TAF period.

SFO Bridge Approach...Weaker wind speeds, otherwise similar to SFO.

Monterey Bay Terminals...Onshore winds increase this afternoon
before easing after sunset. There is moderate confidence for low
clouds to return early Thursday morning resulting in IFR/LIFR
conditions by around 06Z - 09Z

&&

.MARINE...
(Today through Monday)
Issued at 1023 AM PDT Wed May 21 2025

Hazardous marine conditions continue today as strong northwesterly
breezes with near gale to gale force gusts and rough to very
rough seas persist. Winds will slowly diminish and seas will
slowly abate tonight with fresh northwesterly breezes with strong
gusts and moderate to rough seas prevailing Thursday through
Sunday.

&&

.FIRE WEATHER...
Issued at 1252 PM PDT Wed May 21 2025

Including a short fire weather discussion simply to say that
strong gusty onshore winds, especially through gaps in terrain and
along ridges and peaks, will persist through Thursday morning.
This along with humidity in the sub 40 percent range and rapidly
drying grass crops, rapid fire spread in dry grasses is possible
if there is an ignition. Remain fire wise and don`t be the reason
for fire starts.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay.

     Small Craft Advisory until 3 AM PDT Thursday for Pigeon Pt to Pt
     Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt
     Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

     Gale Warning until 3 PM PDT this afternoon for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory until 3 AM PDT Thursday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...BFG
LONG TERM....BFG
AVIATION...RGass
MARINE...RGass

Visit us at www.weather.gov/sanfrancisco

Follow us on Facebook, X, and YouTube at:
www.facebook.com/nwsbayarea
x.com/nwsbayarea
www.youtube.com/nwsbayarea