246
FXUS66 KMFR 071138
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
438 AM PDT Mon Oct 7 2024

Updated AVIATION section

.SHORT TERM...Above normal, very warm temperatures are expected
today and Tuesday across inland areas. Meanwhile, weak upper
level trough will move into northern California today. This
disturbances will bring some mid level moisture and instability
into the area. Models support a low (10-20%) chance for showers
and thunderstorms in central/eastern Siskiyou, Modoc, southeast
Klamath and southern/central Lake Counties today. The area with
the best chance for showers or thunderstorms is Modoc County
though. This disturbance will shift eastward Monday night then
expect dry weather across the area on Tuesday. Both today and
Tuesday, expect very warm temperatures to affect inland areas with
highs 15 to 20 degrees above normal (upper 80s to 90s for valleys
west of the Cascades and low to mid 80s for valleys east of the
Cascades).

Tuesday night into Wednesday the high pressure ridge shifts
eastward and the area is under southwest flow aloft. A weak front
will move onshore Tuesday night and early Wednesday. This may
bring some light rain to the coastal areas and inland into Douglas
County. Otherwise, expect a return to more seasonable
temperatures. Friday into Saturday, a low pressure system arrives
from the west. Deterministic GFS and ECMWF favor this low tracking
into northern California but there is more variability in the
track and strength of the system in the ensembles (see previous
long term discussion below). So confidence is low on the details
of this system and we will continue to monitor and update as
confidence improves.

&&

.AVIATION...07/12Z TAFs...There is just enough of an offshore
component to the low-level winds that most areas near the coast will
maintain VFR this morning. Patchy shallow valley fog is possible
(20% chance) near coastal tributaries and rivers. Other than that,
VFR prevails all areas today with mostly light winds. This
afternoon, there is a slight chance (15%) of thunderstorms over
portions of the east side, but almost certainly south and east of
Klamath Falls. Some IFR fog/stratus should move back into coastal
areas tonight as flow turns back onshore. -Spilde

&&

.MARINE...Updated 200 AM PDT Monday, October 7, 2024...North
winds will continue through this morning with steep wind driven seas
to the south of Gold Beach and beyond 10 NM from shore. Longer
period swell will gradually build, increasing surf and breaking
action around bars.

Later today, winds will ease and the swell period will begin to
shorten. Swell dominated seas will remain moderate tonight through
Wednesday. Winds will remain below 20 kts from mid to late week, but
Small Craft Advisory seas are possible again, starting around Friday
night due to building northwest swell. -Spilde


&&


FIRE WEATHER...Updated 300 AM Monday October 7, 2024...Late
summer like temperatures are expected today. Daytime humidities
will also resemble more summer like values, and recoveries will
continue to be moderate to poor again this morning. Westerly winds
will be slightly enhanced east of the Cascades the next few
afternoons, and with low daytime humidities, conditions could
approach critical this afternoon. Additionally, shortwaves will
pass around the northwestern periphery of the high pressure
centered over the southwest. This will result in cumulus buildups
across portions of the Modoc and into southeastern Lake, far
southeast Klamath and eastern/southeastern Siskiyou counties
today. There could be isolated showers or thunderstorms (10-20%
chance) in those areas this afternoon. We`ve included showers and
isolated thunderstorms (10-20% chance) roughly from the Medicine
Lake area northeastward into far SE Klamath and southern Lake
Counties and over much of Modoc county.

On Tuesday, temperatures trend slightly cooler as a weak front
moves onshore. This will bring a slight chance for showers along
the coast as well as into Douglas County. Also expect recoveries
over ridges to trend higher across the ridges, especially along
and west of the Southern Oregon Cascades. Tuesday night into
Wednesday, a shortwave trough moves through the region, pushing
the ridge farther east and breaks it down. This will bring
improving recoveries and a subtle cooling trend with daytime
humidities trending higher through the remainder of the week. Dry
conditions will continue until the end of the week when a front
approaches the region. There remains considerable differences
among the models and ensembles on where and how much precipitation
will occur during the Friday-Saturday timeframe. As is usual, the
better chances are for the Cascades westward, with confidence and
chances decreasing the farther east you go. -CC

&&


.PREV DISCUSSION... /Issued 455 PM PDT Sun Oct 6 2024/

LONG TERM DISCUSSION...There is still quite a bit of uncertainty
in the extended forecast...both with any chance of precipitation
as well as the temperature forecast.

About 60% of the ensemble members indicate precipitation for the
area generally along and west of the Cascades...with the highest
chance being right along the coast. Unfortunately about 40% of
the members indicated in the clusters...keep the upper trough too
far west...with the ridge firmly in place over the forecast area.
This is also seen in the spread of potential temperatures...using
Medford as an example...temperature values range anywhere from the
low 70s to mid 80s on Friday.

With all of the uncertainty...please continue to monitor the
forecast for the latest information. We will remain hopeful for a
change in the weather pattern!

-Riley

&&

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

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 AM PDT this
     morning for PZZ356-376.

&&

$$

CC