540
FXUS66 KMFR 211849
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1149 AM PDT Sat Sep 21 2024

...Updated Aviation Section...


.AVIATION (18Z TAFs)...

North Bend has a chance at MVFR/IFR conditions overnight, but
elsewhere VFR conditions are expected throughout the valid TAF
period. Typical afternoon breezes expected through this period as
well.

Guerrero

&&

.PREV DISCUSSION... /Issued 1011 AM PDT Sat Sep 21 2024/

DISCUSSION...The marine section has been updated. An update to
the forecast is not necessary. East winds over ridges,
strongest over the Coast Range, will continue into Monday morning.
This will produce a Chetco Effect, with high temperatures likely
into the lower 80s at Brookings today, Sunday, and Monday.

Temperatures will trend higher into Tuesday, then trend lower for
the second half of next week. A weak front will bring a chance of
light rain to the coast, Douglas County and northward Wednesday
afternoon into Wednesday night. Another notable feature of this
front will be the development of gusty, windy, westerly winds east
of the Cascades on Wednesday afternoon/evening. A weaker front on
Friday will likely be limited to producing additional cooling.
-DW

AVIATION...21/12Z TAFS...VFR will prevail area wide for the next 24
hours due to low-level offshore winds west of the Cascades and a
drying air mass. Gusty north winds (~30kt) are expected at North
Bend again this afternoon/evening. -Spilde

MARINE...Updated 800 AM Saturday, September 21, 2024...A thermal
trough and associated pressure gradient along/near the coast will
remain in place through early next week; as a result, strong
northerly winds  and very steep seas are expected south of Port
Orford. Elsewhere, steep seas and advisory strength northerly winds
are expected north of Port Orford through today. The Small Craft
will be extended to all waters tonight, and this continues until the
steep seas focus south of Coos Bay 5 AM Sunday.

The thermal trough is forecast to move inland with weakening winds
and easing seas late Tuesday into Wednesday. This will result in
relatively calm seas and light wind speeds through at least Friday.

-Guerrero/Spilde

PREV DISCUSSION... /Issued 202 AM PDT Sat Sep 21 2024/

DISCUSSION...Overall quiet conditions are expected over the next
several days, with upper level ridging overhead, a thermal trough
along the coast, and with a few exceptions, generally seasonable
weather across the region. With the ridge in control, the area
will remain dry until the mid-to-late next week, when the next
front is due to pass through the area. Until then, expect warm
afternoons, cool nights, and typical afternoon breezes.

Along the immediate coast, the thermal trough will continue to
produce gusty north winds, with occasional periods of fog and/or
low clouds as the marine layer make periodic inland pushes. These
clouds and fog will stay west of the coastal mountains, however,
as the thermal trough will also result in a general dry, east wind
flow that will scour out much of the moisture and keep the marine
layer at bay. This same wind is likely to produce an ongoing
Chetco Effect as well, keeping temperatures warmer than normal
along the south coast near Brookings,

Inland, temperatures will remain around or just above normal for
this time of year, which means the first day of Fall on Sunday
will feel like a typical day in mid-September. Fall will not
arrive for good, however, when temperatures jump back up to
summertime values Tuesday and Wednesday as the upper level ridge
axis amplifies and passes overhead, making those days feel more
like late July or early August.

As mentioned above, this dry pattern may change a bit with the
arrival of a front Wednesday into Thursday, and another Thursday
night into Friday. These systems appear pretty weak in the latest
model suites, with little in the way of moisture content, and
with much of the energy well to our north. So, other than some
light rain possible along the coast and into the Umpqua Basin,
along with increased winds over the ridges and across the East
Side, the passage of the systems look like they will do little
more than bring temperatures back down to more seasonable values
as we head into next weekend. -BPN

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Frost Advisory from 2 AM to 9 AM PDT Sunday for ORZ029>031.

CA...Frost Advisory from 2 AM to 9 AM PDT Sunday for CAZ085.

PACIFIC COASTAL WATERS...Small Craft Advisory until 5 PM PDT Sunday
     for PZZ350-356-370-376.

     Hazardous Seas Warning until 11 PM PDT this evening for PZZ356-
     376.

&&

$$