Small Craft Advisory 12, NWS Medford, OR

Area Forecast Discussion
National Weather Service Medford OR
850 AM PST Sun Jan 26 2020

.DISCUSSION...Radar imagery is showing some some lingering showers
mainly east of the Cascades and into Modoc County in California.
There are also some light returns across the Umpqua Divide.
Satellite is consistent in this. Meanwhile, some shallow fog is
occurring in the Rogue Valley and this will dissipate later today.

The next front is coming in tonight, and it will provide the next
bit of precipitation for us. The main goal of our shift will be to
narrow down any snow level issues (none anticipated at the
moment), and precipitation amounts. For now, the forecast looks
good and no changes are needed. -Schaaf

&&

.MARINE...Updated 800 AM PST Sunday, 26 Jan 2020...
Very steep seas associated with the latest front that moved through
the coastal waters will gradually subside from southwest to
northeast early this morning. Steep seas will then generally
continue through Thursday as multiple frontal systems and swell
trains move through. However a period of very steep seas with gale
force winds is possible late Monday morning through Monday night as
the next front moves into the waters.

Steep west seas are expected today through tonight with seas
increasing from 11 to 14 feet at 16 seconds today to  14 to 16 feet
at 16 seconds tonight.

As south winds increase Monday into Monday  night expect a mix of
steep to very steep seas, peaking at 15 to 18 feet. Southerly winds
are likely to reach gale force late Monday morning through Monday
night for much of the area north of Gold Beach as a coastal jet
stream develops ahead of a strong front. Guidance has shifted the
gale force winds closer to the coast from Gold Beach northward as
compared to yesterday's guidance and has delayed the period of
concern by 6 to 12 hours.

The next front after that system will cause southerly winds to peak
Wednesday, probably in the 20 to 30 knots range from about Gold
Beach northward.

The active pattern will then continue, with northerlies possibly
developing behind a front next weekend as we finally get onto the
western side of the long wave trough driving the storm activity.
-Lutz/CC

&&

.PREV DISCUSSION... /Issued 416 AM PST Sun Jan 26 2020/

DISCUSSION...A cold front will exit the area this morning with
precipitation mainly from the Cascades eastward. Conditions will
be mainly dry this afternoon, though with a slight chance to
chance of light showers. The probability will be highest at the
coast and over the mountains.

The next front will reach the coast tonight with wetter
conditions from an atmospheric river event to follow Monday into
Tuesday. The focus for the short term portion of the forecast was on
precipitation amounts. 48-hour Rainfall amounts will be highest
near the coast and over the Coast Range with around 1.50 to 3.50
inches expected. Elsewhere, around 0.25 to 1 inch is expected
along the Interstate-5 corridor, and less than 0.50 inches for
most portions of the east side...perhaps a bit more than that for
northern Klamath County.

Snow levels will be around 5000 to 6000 feet for most areas
during most of the event. So, we will only get noteworthy snowfall
over the higher terrain with the main impact along the higher
Cascade passes. This includes around 6 to 12 inches of snow
expected for portions of Highways 62 and 138 near Crater Lake and
Diamond Lake, and possibly a few inches both along the crest of
Highway 140 by Lake of the Woods and in far northern Klamath
County near Chemult.

The rain rates will be sufficiently high to produce areas of ponding
of water on roadways, and further rises on rivers, creeks, and
streams. But, it is consistent with the forecast issued yesterday
afternoon that travel impacts seem pretty limited as do main stem
river flooding concerns. Otherwise, the precipitation will
continue building some high elevation snowpack.

From Wednesday into the weekend, high pressure over California
will very likely not be strong enough to produce completely dry
weather. But, it will push the focus of the storm track north of
our area with the highest probability of precipitation in our area
during each of the disturbances for the coast and Douglas County.
Throughout the long term, there are important model differences
in just how the strength of the ridge fluctuates as the next in
the series of frontal systems moves over the top of the ridge.
As such, there is high uncertainty in the specifics of the
forecast for valley low clouds and fog. But, a high probability
that night and at least early morning stratus will be common in
west side valleys.

AVIATION...For the 26/12Z TAF Cycle...
A mix of MVFR and VFR is generally expected along with showers this
morning. Some IFR does exist across coastal Curry County, likely
resulting in near total terrain obscurations in the coastal
mountains. Further inland some fog banks trapped in the terrain
could result in brief and isolated IFR/LIFR through about 16Z. Also,
expect partial terrain obscurations this morning. Late this morning
into this evening VFR is mostly expected along with partial terrain
obscurations as we get a general break between frontal systems.
Still, a few upslope showers under southerly flow are still
expected. This evening through tonight, MVFR is likely to develop as
the next frontal system begins to push in. Some wind shear will be
possible along and near the coast, to include KOTH. ~Lutz

&&

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

CA...None.

Pacific Coastal Waters...Gale Watch from Monday morning through late Monday night for
     PZZ350-356-370-376.
     Small Craft Advisory until 10 PM PST Thursday for
     PZZ350-356-370-376.