FXUS66 KMFR 150540
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1040 PM PDT Mon Oct 14 2024

...Updated aviation discussion...

.DISCUSSION...Satellite imagery shows higher clouds associated
with a frontal boundary beginning to push toward southern Oregon
and northern California with some marine stratus occurring
underneath these clouds. This is the front that will be arriving
at some point tomorrow and could produce a little bit of rainfall
across the area. Winds will be a bit breezier tomorrow ahead of
the front. In all, the forecast looks well enough along. Please
see the previous discussion below for more details. -Schaaf

&&

.AVIATION...15/06Z TAFs...A weak frontal system is bringing
increasing cloud cover to coastal areas that will gradually spread
inland overnight into Tuesday. Expect IFR/LIFR along the coast this
evening with a little light rain/drizzle around or after 09z. These
low conditions probably last through Tuesday morning. Farther
inland, VFR conditions will prevail through tonight and into
Tuesday. The exception being in the Umpqua Basin, with MVFR likely
developing around sunrise. Precipitation with the front will fall
apart as it heads inland, so while there's a 20% chance of rain at
Roseburg Tuesday morning, probabilities were not high enough to
include in the TAF. Medford and Klamath Falls will be VFR with some
high cirrus at times and mostly light winds through Tuesday morning.
An approaching front at the end of the current TAF period will bring
some stronger winds to areas east of the Cascades Tuesday afternoon,
as well as increasing cloud cover. /BR-y

&&

.PREV DISCUSSION... /Issued 429 PM PDT Mon Oct 14 2024/

DISCUSSION...Warm and stable weather continues today across
northern California and southern Oregon under the back side of an
upper ridge. Temperatures across the area will remain about 10
degrees above seasonal averages today. Areas west of the Cascades
will see similar temperatures to Sunday, and areas to the east
will warm by no more than 5 degrees as the ridge axis over that
area.

On Tuesday, an upper trough will approach in the wake of the ridge
and bring cooler conditions. Temperatures will remain about 5
degrees above normal on Tuesday afternoon under this shifting
pattern, with more cooling possible if cloud cover moves over the
area earlier than expected. An initial cold front may bring
precipitation to coastal counties during the day Tuesday (10-30%
chances), with chances increasing in the evening. This first front
will support elevated precipitation chances (50-100%) through the
day Wednesday as it moves eastward, with the highest rainfall totals
expected the Cascades and over Modoc and southern Lake counties.
Temperatures on Wednesday will fallow just below seasonal averages.

A second cold front will follow on Thursday, bringing another round
of precipitation across the area. Coastal ranges, especially at and
north of Cape Blanco, are expected to see more rainfall with this
front. Colder air will move over the area, lowering snow levels to
4500-5000 feet during the day Thursday. This could bring 1 to 4
inches of rainfall over the Cascades on Thursday morning and
afternoon. Residual surface warmth makes any accumulation on roads
unlikely. This cold air will also bring widespread below freezing
temperatures to areas east of the Cascades on Wednesday and Thursday
nights, with chances of frost-making temperatures reaching into west
side valleys.

Winter weather hazards are not expected to be needed with these
fronts. However, extra caution is encouraged during travels through
this period. Initial precipitation may lift accumulated oils to
road surfaces, further reducing traction on rain-wet roads. Debris
on roads may accumulate along areas where water flows. Lingering
water on roads and sidewalks may freeze overnight on Wednesday and
Thursday night.

Temperatures will hover around seasonal norms as conditions dry out
on Friday and Saturday. Deterministic guidance for both the GFS and
ECMWF models suggest another round of rainfall on Sunday into Monday
morning, although uncertainty follows. Ensemble guidance for both
models show frequent but unorganized precipitation chances beyond
next Monday, with the most agreement appearing late next week. While
the timing will continue to develop, the meteograms for both models
suggest that precipitation will stay in the forecast through the end
of October. -TAD

MARINE...Updated 200 PM PDT Monday, October 14, 2024...South winds
will shift to northerly tonight into Tuesday, but remain generally
light as a weak front moves onshore. Even so, a long period moderate
west swell will bring high, steep and hazardous seas tonight that
will gradually subside through Tuesday. Another front will move
through late Tuesday night into Wednesday with some rain. Moderate
south winds in advance of the front will once again shift to
northerly by morning. A third front will move through Wednesday
night into Thursday with breezy north-northwest winds followed by a
moderate northwest swell. -Spilde

BEACH HAZARDS...Updated 200 PM PDT Monday, October 14, 2024...Long
period westerly swell and an existing long period southerly swell
will combine to bring a moderate risk of sneaker waves to area
waters through this evening. As such, a beach hazards statement
remains in effect until 8 pm PDT.

Sneaker waves are an unpredictable wave that can surge farther onto
the beach than expected. These waves can roll logs and carry large
debris as they move up the beach. The wave itself or the objects
caught in it can knock beachgoers off their feet and sweep them out
into the cold open water. Cold water immersion can be dangerous,
even deadly. -Spilde

FIRE WEATHER...Updated 200 PM Monday October 14, 2024...Increased
west to southwest winds are on tap Tuesday in advance of the
week's first cold front. There are some fair uncertainties as to
how much rain will fall, but confidence is 50-65% that the
Cascades north of highway 140 will receive wetting rain.
Thereafter through Thursday, lowering snow levels with additional
frontal passages will bring periodic rain and mountain snow
showers, most abundant across the Cascades westward. Wetting rains
should impact the majority of this area with several inches of
snow for the Cascades above 4000 feet by Thursday mooning. A
pattern change is on tap for the weekend. Stavish

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 2 AM PDT Tuesday
     for PZZ350-356-370-376.

&&

$$