783
FXUS66 KMFR 142150
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
250 PM PDT Fri Jun 14 2024

.SHORT TERM...Tonight through Monday.

The weather in the short term could be considered the last bit of
spring for the year, with temperatures around 10 degrees below
normal during the weekend, then higher uncertainty with a
potential for further cooling on Monday. Currently increasing
high clouds are associated with a dry front approaching this
evening. This will bring a push of mid-level (bases at 4500-6500
ft msl) stratocumulus clouds into southwest Oregon late this
evening into Saturday morning. This layer looks to be sufficiently
deep to spill over the Umpqua Divide into Josephine and Jackson
counties.

We will experience cooling, breezy afternoon westerly winds, and
fair high weather clouds across the area, with the impacts on
Saturday from a trough centered near the canadian border largely
occurring north of our area. The mid-level clouds will linger
longest, until almost noon, for northern portions of Coos and
Douglas counties.

A weaker marine push will follow Saturday night into Sunday
morning, with a thinning of the high clouds. This will aid
cooling. A Freeze Watch has been issued for most of our area east
of the Cascades for Saturday night. In around 25% of years, the
east side will have a freeze this late into June. Meantime, of
course, it will also be cold on Sunday morning on the west side
with lows in the lower to mid 40s expected to be common.

Uncertainty in the forecast for Sunday afternoon into Monday
afternoon is higher than usual. A stronger front rotating around
the slow-moving low in the Pacific Northwest is expected to
weaken as it tracks inland. The strength and positioning of this
wave have a wide range of solutions among the ECMWF and GEFS ensemble
members. The forecast leans slightly wetter than the NBM solution,
with a widespread slight chance to chance probability of light
rain in order to highlight the risk of an honest to goodness
rainfall, especially west of the Cascades, with the highest
probability during late Sunday evening into early Monday morning.
The operational version of the GFS leans toward the wetter side of
the solutions, a little wetter than our forecast, while the
weaker ECMWF is more representative of the NBM. We will be
watching this closely for potential adjustments as data updates.


.LONG TERM...Monday night through Friday night.

The upper low is expected to gradually move eastward Monday
night. Then, Tuesday through Friday, models indicate weak trough
to near zonal flow over the region with a high pressure ridge
offshore.

With this pattern expect daytime temperatures to trend warmer
(becoming slightly above normal) and generally dry conditions.
Overnight low temperatures will be cool to mild Monday night/Tuesday
morning, with a potential for areas of frost conditions in valleys
east of the Cascades. For Monday night/Tuesday morning, National
Blend of Models indicates a 50-60% chance for low temperatures in
the mid 30s in valleys east of the Cascades (Klamath Falls, Lakeview
and Alturas) with a 20-25% chance for low temperatures down to 32.
Areas in northern Klamath County, near Chemult, have a higher chance
(60-80%) for freezing conditions (32 deg and below) during this
period. Overnight/morning low temperatures will trend warmer Tuesday
night through late in the week.  Northerly winds maybe gusty during
the afternoons/evenings for areas along the coast as a surface
thermal trough builds beginning Monday night into Tuesday.
Otherwise, expect typical diurnal breezes across the area.

&&

.AVIATION...14/18Z TAFs...VFR conditions are present across northern
California and southern Oregon this morning, and are expected to
continue through the TAF period. High clouds will move over the area
this afternoon and evening, but nothing that will change any flight
levels. Gusty afternoon winds in the Rogue Valley and east of the
Cascades will calm into the evening. Guidance suggests a 20-30%
chance of MVFR ceilings over the Oregon coast north of Cape Blanco
near the end of the TAF period, but confidence is not high enough to
include those ceilings in this round of TAFs. -TAD

&&

.MARINE...Updated 200 PM Friday, June 14, 2024...Northerly winds
continue to build steep seas south of Gold Beach this afternoon as a
thermal trough weakens. A Small Craft Advisory will remain over
these waters through 11 PM tonight.

Seas will be calm to start off the weekend, with slight (10-30%)
precipitation chances north of Cape Blanco through the day Saturday.
A weak thermal trough will return Saturday evening and rebuild steep
seas south of Ophir. A Small Craft issue is in place for Saturday at
5 PM through Sunday at 11 PM to cover this expected period of steep
seas.

Activity will continue through the weekend and into next week, but
the timing and sea state forecast will both benefit from extra
guidance. Another upper level disturbance is expected to move over
the area, bring more slight precipitation chances (10-20%) over and
wind gusts of 15 to 20 kts over all waters Sunday into Monday
morning. A wider thermal trough is forecast to build on Monday
evening and remain into midweek, bringing wind-built steep seas to
most if not all waters and gusts of near 30 kts south of Gold Beach.
Long-term probabilistic guidance currently has low (10-30%) chances
of waves over 9 feet limited to Brookings and farther south through
next week, so anything more than steep seas is not currently
expected. -TAD

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Freeze Watch from late Saturday night through Sunday morning for
     ORZ029>031.

CA...Freeze Watch from late Saturday night through Sunday morning for
     CAZ084-085.

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

     Small Craft Advisory from 5 PM Saturday to 11 PM PDT Sunday for
     PZZ356-376.

&&

$$