FXUS66 KMFR 020016 AAA
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
515 PM PDT Fri Nov 1 2024

.UPDATED...Aviation Discussion.

.AVIATION...02/00Z TAFs...Showers will persist tonight behind a
front then become focused mainly from the Southern Oregon Cascades
west on Saturday. Widespread MVFR conditions and local IFR along
with widespread mountain obscurations are expected this evening and
tonight. These conditions will likely continue into Saturday
morning, then expect some improving conditions during the Saturday.
However, will likely see continued areas MVFR and local IFR from the
Southern Oregon Cascades west in showers. -CC

&&

.SHORT TERM...Pretty impressive dynamics came through at the base
of the digging trough this morning. Good shear and instability
lead to some impressive coastal thunderstorms that moved onshore.
These had some rotation signatures and a couple special marine
warnings were issued. No reports of anything severe have been
heard yet. The southward digging short wave is being propagated by
a strong upper northerly jet that will be moving over the CWA
tonight as the trough axis moves east. During this progression
through the evening, the broad region of light to moderate rain
and mountain snow showers will be moving south and east and
diminishing with time. Snow levels near 5500 ft. Will allow the
Winter Storm Warning to expire as scheduled, however additional
accumulations will continue overnight thought rates will be less
than significant impact.

Another strong branch of the polar jet positions northwesterly
over the region Saturday which will allow for some shortwave
energy to continue to impact the area with continued rain and
snow shear chances right into Sunday as the axis of the jet starts
to pull east. Significant ridging tries to build in Monday but
another shortwave digging into Washington and northern Oregon is
indicated to compromise this trend. Some shower chances come in
again Monday mainly for the coast and Umpqua. Stavish

.LONG TERM...(Monday through Friday)...The models are in
pretty good agreement showing an upper trough moving along the north
part of the upper ridge Monday and bringing a front into our area.
Suspect the QPF is a bit overdone with this given the shortwave will
be pushing into the upper ridge. The most likely scenario will be
that the precipitation associated with the front will lose it's
punch as it moves towards our area, this limiting not only the
amount of precipitation, but keeping it confined to the northern
Cascades and north of the Umpqua Divide and north coast. The
individual ECMWF ensemble goes with the idea that the shortwave gets
washed out as it encounters the upper ridge. After Monday, the
general consensus is for dry weather to return Tuesday and lasting
through Thursday. Tuesday, we'll be on the western edge of a
shortwave that will move from north to south in eastern washington
and Oregon. Given there is no over water trajectory. It's likely
we'll end up dry with breezy north winds east of the Cascades
Tuesday afternoon into the early evening hours. The models still
show some precipitation, which is suspect given the pattern which
typically does not favor precipitation.

The shortwave will dig south and evolve into an upper low near the
for corners by mid next week with upper ridging building into the
area that will last through Thursday. We'll have chilly overnight
lows for the interior westside valleys Tuesday, Wednesday and
Thursday night and it will be cold east of the Cascades. Afternoon
temperatures will be milder, however it could be cooler than what's
in the forecast if the inversion is strong enough, especially for
the interior westside valleys.

Friday is likely to remain dry. There' are some hints at an upper
trough approaching later Friday, but there's more evidence pointing
towards a persistent ridge that will flatten out some. -Petrucelli


&&

.MARINE...Updated 830 AM PDT Friday, November 1, 2024...Rain and
periods of gusty winds will continue through Saturday as several
disturbances pass through the region. Seas subside some tonight
through Saturday, but will remain elevated and steep. A large, long
period northwest swell will arrive later Sunday into Monday, peaking
at 15 to 19 feet. Periods initially as the swell arrives will be
near 24 seconds, then settle to around 16-18 seconds at the peak of
the swell Sunday night into Monday morning. This will potentially
produce very steep seas, very rough bars, and high surf conditions.

Ridging will gradually build into the area with north winds
returning next week. -Spilde/BPN

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning until 5 PM PDT this afternoon for ORZ027-
     028.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 10 AM PDT Sunday
     for PZZ350-356-370-376.

&&

$$