-- Discussion containing changed information from previous version are highlighted. --
967
FXUS66 KMFR 301758
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1058 AM PDT Tue Apr 30 2024

Updated AVIATION Section

.UPDATE...The weak front and upper level trough are passing
onshore this morning, with very light showers along the coats and
into the Umpqua Basin. The rest of the area remains mostly dry,
although a few light sprinkles are not out of the question
anywhere along and west of the Cascades. Meanwhile, cooler
temperatures did result in some areas of freeze in the Illinois
and Applegate valleys this morning, but increased clouds and
sunrise have brought these temperatures up, so the Freeze Warning
has been ended early. A few other updates were made to the
forecast to bring it in line with the current observations, but no
major changes were necessary. See the previous discussion below
for more details on this and the rest of the forecast. -BPN

&&

.AVIATION...
-- Changed Discussion --
30/18Z TAFs...VFR will prevail over a large portion of
the forecast area today through Wednesday morning. A weak front
pushing onshore now is leading to onshore flow and scattered showers
for areas near and west of the Cascades. Temporary MVFR ceilings or
briefly reduced visibility can occur in any of the heavier showers
as well as partial terrain obscurations, but even then lower
conditions should only last for a half hour or so. Gusty NW winds
are expected in Medford (~20kt) and Klamath Falls (~30kt) this
afternoon/evening til around 3-4Z.

Tonight, breezy conditions ease and showers end. Low-level moisture
could lead to MVFR ceilings in portions of the Umpqua Basin,
including Roseburg, later tonight (after 06Z) until early Wednesday
morning (around 16-17Z). But again, most areas remain VFR. -Spilde
-- End Changed Discussion --

&&

.MARINE...Updated 800 AM Monday, April 30, 2024...Seas will be
hazardous to small craft through this evening with a combination of
wind-driven seas and northwest swell. A surface low pressure will
move inland today with high seas building to a peak this evening. A
weak surface high will move in over the waters Wednesday with
moderate north winds, highest south of Cape Blanco. Then, another
front will move through the waters Wednesday night and onshore
Thursday with winds and wind wave dominated seas likely reaching
small craft advisory levels. A break with calmer conditions is
expected Thursday night into early Friday. A series of fronts is
likely to follow Friday into early next week with stronger winds and
building seas with multiple chances for rainfall.


&&

PREV DISCUSSION... /Issued 315 AM PDT Tue Apr 30 2024/

DISCUSSION...Spring continues to be spring-like this week, with
persistent northwest flow and a progressive pattern leading to
changing conditions each day. A series of fronts will move
through the region, bringing wet and cool conditions with drier,
warmer breaks in between each system.

The first trough in this series will slide north of us through WA
State/northern OR today. We`re on the far south end of this, so
as far as precipitation goes we`re expecting light, on-and-off
again stuff in Coos, Curry, and Douglas counties as well as the
south OR Cascades. Snow levels are in the 2,500-3,500 foot range,
but snowfall will be light overall, with light snow in the
southern OR Cascades (generally under an inch up to 2-3 inches
over the peaks) and a dusting possible in the Klamath Mtns. in
east Curry/west Josephine. With plenty of breaks in the clouds
allowing heat to escape from the lower levels, especially in the
southern and eastern portions of the region, lows this morning
will be chilly. The Freeze Warning in the Illinois Valley
(Josephine County) looks to be on track, as both the temperature
and dewpoint have dropped into the mid-to-low 30s at the airport as
of writing this, with further cooling to the low 30s expected a
little later this morning.

As the shortwave exits to the east later today, showers will
quickly taper off late this evening, and cloud cover will further
break up and clear overnight. This will result in another chilly
morning Wednesday followed by a warmer (compared to today`s highs)
afternoon. The next system will already be approaching by late
Wednesday afternoon/evening, however, so high clouds will begin
moving in and preventing the day from being completely clear.
Light precipitation looks to start at the coast Wednesday night,
spreading ESE overnight into the morning, with light lingering
showers into the afternoon. This system will be slightly stronger
and dip further south than today`s, resulting in more areas seeing
precipitation in southwest OR. Precipitation will remain on
lighter side for the most part, with more moderate rates over the
Cascades and Curry County mountains. Another couple of inches of
snow are expected over the Cascades, and light snow above 4,500
feet or so is possible (30-50% chance) in Lake and Klamath
counties Thursday morning, including along Hwy 97 north of
Chiloquin or so. Light amounts combined with warmer roads and
marginal temperatures (high 20s to low 30s) will make it unlikely
for snow to accumulate on roadways for the most part, however.

Another transient ridge builds into the area late Thursday into
early Friday, resulting in another brief dry period. Another,
stronger, system quickly dives down from the Gulf of Alaska Friday
morning and resumes wet weather in the region as it moves eastward
into early Saturday. Ensemble tools indicate much more moisture
available to this system, with widespread, moderate precipitation
through large portions of the region. On-and-off again
precipitation looks to continue through the weekend, and odds are
wetter, cooler weather will continue next week. -CSP

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT this
     evening for PZZ356-376.

Small Craft Advisory until 11 PM PDT this evening for PZZ350-
     370.

&&

$$