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556
FXUS66 KMFR 202137
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
237 PM PDT Thu Jun 20 2024

.DISCUSSION...
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Thicker high clouds continue to push off to the
east of the Cascades this afternoon and the coastal stratus has
all but retreated to the beaches north of Cape Blanco and also
south of Pistol River. This is resulting in widespread sunny skies
with a warm afternoon over inland areas with the cool Pacific
waters and marine layer providing much cooler conditions along the
coast. While those coastal locations are having temperatures
struggle to reach 60F, inland areas are feeling it warm up. Most
places are about 3-5 degrees higher than this time yesterday and
will end up in the low to mid 80s over the east side and in the
upper 80s to low 90s in the west side valleys.

The weather pattern won`t change much over the next couple of
days, but heights will continue to rise with weak short wave upper
ridging traversing the area. So, we`ll see temperatures respond
and it will get hot inland both Friday and Saturday. Coastal areas
will remain cool by comparison due to nightly marine intrusions
and even a little of drizzle from the cloud layer at times. The
heat inland isn`t uncommon for this time of year, so we aren`t
expecting widespread record-breaking heat, though one or two sites
may challenge their record highs (Mt Shasta City being the most
likely to do so, primarily due to their shorter period of record).
Their records for Friday/Saturday are 95F (2021) and 96F (1992),
respectively, with the official forecast currently just one degree
shy of those records. West side valleys will have highs in the
low to mid 90s, with upper 90s to around 100F for the Shasta,
Scott and lower Klamath river valleys of western Siskiyou County.
Northeast California and the east side in Oregon will have highs
in the upper 80s and low 90s, but maybe mid 90s on Saturday.
Breezy west-southwest winds (15-25 mph with gusts of 30-35 mph)
are expected to increase Saturday afternoon and evening,
especially over the east side.

A mostly dry front will move through Saturday night into Sunday,
though it will serve to deepen the marine layer along the coast
and into portions of the Umpqua Basin. These areas stand a low
chance (15-25%) of some light rain and/or drizzle then. Expect
slight cooling behind the front (5 degrees or so). It`ll be breezy
again Sunday afternoon/evening. Southwest flow aloft will prevent
deep moisture from coming up from the south early next week. So,
other than some high clouds area wide and marine stratus along
the coast, both Monday and Tuesday will be sunny and dry with
temperatures above normal. Tuesday could be hot again.

Models continue to hint at a deeper trough swinging through the
PacNW mid-late next week, but the timing and strength details are
still up in the air. Even so, this should keep things from getting
too hot around here. -Spilde
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&&

.AVIATION...
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19/18Z TAFs...IFR ceilings are slowly receding to the
coast and should clear within the next 2 to 3 hours as strong north
winds develop this afternoon. The IFR/LIFR ceilings & Vis will
become extensive again early this evening then persist into Friday
morning.

Inland, VFR ceilings will persist through the TAF period, with
cirrus moving off to the east, leaving a truly blue ski day. There
could be some high level smoke (6kft or higher) moving in from fires
burning in California during the evening, but we are not expecting
much if any to become trapped at the surface.
-Miles
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&&

.MARINE...
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Updated 230 PM Thursday, June 20, 2024...High pressure
offshore and a thermal trough along/near the coast will remain in
place through Monday. This will result in persistent northerly winds
and areas of steep to very steep wind-driven seas. Winds will be
strongest south of Pistol River, with hazardous seas expected in
that area. The thermal trough is expected to peak Friday and this
will maintain advisory seas south of Cape Blanco, but north of the
cape, conditions are expected to begin to calm.

Slight improvement is expected Saturday into Saturday night as a
front brings a surge of stratus with light showers possible.

-Miles/DW
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&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 2 AM PDT Saturday
     for PZZ356-370-376.

Hazardous Seas Watch from Friday afternoon through late Friday
     night for PZZ356-376.

&&

$$

MAS/JWG/MCB