816
FXUS66 KMFR 192117
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
217 PM PDT Sat Oct 19 2024

.SHORT TERM...Saturday night through Monday night...Upper level
ridging continues to bring stable conditions to southern Oregon and
northern California this evening. Today and Sunday will remain about
10 degrees above seasonal averages, with daytime highs in the mid to
high 70s west of the Cascades and mid to high 60s to the east.

The ridge will start to break down on Sunday, allowing a cold front
to approach the area on Sunday evening. Showers are expected from
Sunday evening through Monday afternoon, with the highest amounts
along the coast on early Monday morning then moving inland through
the day. Forecast totals have dropped slightly, with about 0.75
inches of rainfall expected along the coast and over 0.5 inches for
interior Coos and Curry counties as well as over the Cascades. The
Umpqua, Illinois, and Applegate valleys will see 0.3 to 0.4 inches
and the Rogue Valley will see 0.2 inches or less.

Probabilistic tools still suggest a wide range of possibilities,
although there is more confidence towards higher amounts. Using
Brookings as an example, early Monday morning amounts vary from 0.6
to 1.0 inches. In the same period, Medford could see nothing to 0.3
inches. The takeaway from this is that rainfall amounts could vary
in local areas, even with expectations of widespread rainfall. While
no hazardous conditions are expected, moderate to heavy rainfall may
make driving difficult especially in coastal or elevated areas.

Outside of rainfall, this cold front is expected to be unimpactful.
Elevated winds are expected east of the Cascades on Sunday evening,
but nothing near advisory levels. Monday`s daytime temperatures will
cool across the area. Monday`s nighttime lows will stay above frost
conditions west of the Cascades. East of the Cascades, northern Lake
and Klamath counties will see lows in the low to mid 20s and other
areas will be near freezing conditions. -TAD

.LONG TERM...

A high pressure ridge will build over the region late Tuesday into
Wednesday. Offshore, to the west, a trough will deepen into a low
with a frontal system developing. This front and low pressure will
approach the coast late Thursday into Friday. Models and ensembles
are showing varying solutions on the strength and timing of this
system. So confidence is low on the details of when it will move
inland and how much precipitation it may bring.  It`s also worth
noting some members(10-15%) are completely dry and are not showing
anything during this period, late Thursday and Friday.  Given the
southwest to northeast track and time of year, snowfall doesn`t
appear to be in our future as snow levels remain around 7000 feet.
Models and ensembles then support a cool and wet pattern after
Friday. A low pressure system in the Gulf of Alaska is forecast to
send a front into the region on Saturday. This may be followed by
additional fronts moving into the region from the northwest. -CC


&&

.AVIATION (18Z TAFs)...

Inland, confidence is high for VFR conditions through this cycle.
Along and near the coast is more complicated as both low clouds and
visibility restrictions could develop tonight leading to IFR/LIFR
conditions. These chances start this evening (around 20% chance)
then rise to 40-50% overnight tonight into Sunday morning for KOTH.
Otherwise, increasing high clouds along with light wind speeds are
expected through this cycle.

-Guerrero/Wright

&&

.MARINE (Updated 200 PM)...
Relatively light winds and subdued seas continue through tonight.
Winds switch to south and increase ahead of a cold front tomorrow,
and this could bring brief, isolated hazardous conditions due to a
combination of steep wind waves and westerly swell, mainly north of
Cape Blanco. Expect rain with the front Sunday evening and night,
then the front moves onshore with improving conditions Monday. A
thermal trough develops along the coast Tuesday, and this will bring
gusty north winds and wind driven seas that will reach at least
advisory levels Tuesday into Wednesday, especially south of Cape
Blanco. -Wright

&&

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

CA...None.

PACIFIC COASTAL WATERS...None.

&&

$$

TAD/CC/TRW