614
FXUS66 KMFR 052346
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
446 PM PDT Sat Oct 5 2024

...Updated AVIATION discussion...

.DISCUSSION...The overall trend of dry conditions with seasonably
cool mornings that warm up to late summer like temperatures will
remain in place through around mid-week. High pressure will continue
over the southwest US and southern OR/NorCal will be on the
northwest periphery of this high. This will bring subtle changes to
the day to day forecast, but overall the daily pattern will be rinse
and repeat.

Afternoon breezes will be slightly enhanced east of the Cascades
today and again on Sunday. High temperatures trend warmer on Sunday
as the ridge axis nudges northward, and this will be the hottest day
of the forecast period. A shortwave moves up from the southwest
later Sunday on the periphery of the upper level ridge. There isn`t
much instability available for showers/thunderstorms, but there
could be enough moisture for some cumulus clouds to develop across
the southeastern corner of the area (eastern Modoc into southeastern
Lake County).

Temperatures trend slightly cooler on Monday by a few degrees and
the upper level pattern starts to shift as a weak shortwave trough
passes through the region late Monday into Tuesday. This will push
the Southwest ridge axis eastward over the Rockies, gradually
allowing for a broad upper level trough to develop over the eastern
Pacific. There could be a weak front associated with this trough
Monday night into Tuesday, which would once again bring some slight
chances of light precipitation/drizzle to the coast, but models are
in good agreement that much of the region will remain dry.
Temperatures will trend cooler on Tuesday, and this looks like the
start of an overall cooling trend that continues through the end of
the week.

The question then becomes are there any precipitation chances for
the latter half of the week as the broad troughing pattern sets up?
While models generally agree on a trough pattern Thursday into
Saturday, there are differences in timing and any associated
moisture. Precipitation chances have remain fairly steady in the
most recent model runs, maintaining around a 20-40% chance across
the region on Friday. Looking into the ensembles, confidence is
higher for coastal locations to see some rain during this time, but
that confidence decreases heading inland. At this time, if
precipitation does occur, it doesn`t look to be much with a 30-50%
chance for 0.10" over a 48 hour period ending Saturday morning for
areas west of the Cascades, and a 15-30% chance for areas east of
the Cascades. Stay tuned as details become more clear over the
coming days. /BR-y


&&

.AVIATION...06/00Z TAF...The evening is starting with VFR conditions
across northern California and southern Oregon. Marine stratus will
be possible along the Oregon coast tonight, with chances of IFR or
LIFR ceilings and visibilities if the layer develops. Ceilings and
visibilities may decrease in the Umpqua Valley as well, with
moderate chances of MVFR levels and slight chances of IFR. Any cloud
cover that develops should be clear by late Sunday morning or early
in the afternoon. -TAD

&&

.MARINE...Updated 200 PM PDT Saturday, October 5, 2024...North
winds will gradually increase south of Cape Blanco Sunday with Small
Craft Advisory conditions developing by mid to late afternoon and
continuing through Monday morning, then easing Monday afternoon.
Longer period swell will arrive early Monday morning and build
through the morning, increasing surf and breaking action around
bars. The swell period will then slowly decrease Tuesday night
through early Wednesday. Winds will remain below 20 kts from mid to
late week, but Small Craft Advisory seas should return by Friday.
Stavish

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory from 2 PM Sunday to 11
     AM PDT Monday for PZZ350-356-376.

&&

$$