Area Forecast Discussion
Issued by NWS Medford, OR

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FXUS66 KMFR 082138
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
238 PM PDT Sat Aug 8 2020

.DISCUSSION...An upper level ridge, which is centered offshore,
extends into the area. This ridge will remain in place through
Monday. At the surface, a thermal trough is located along the
coast. With this pattern expected warming temperatures for inland
areas through Monday with afternoon breezy to gusty north to
northwest winds. At the coast, expect strong gusty north to
northeast winds through Monday, strongest in the afternoons and
early evenings.

Temperatures will trend warmer across inland areas through
Monday. Models continue to support highs peaking in the 90s to
lower 100s across most inland valleys Monday afternoon. Along
coastal areas, the thermal trough is resulting in gusty north to
northeast winds, with strongest winds occurring in the afternoons
and evenings through Monday. Northeast (offshore ) winds will
also bring a Chetco warming effect to the southern Curry coast
near Brookings with high temperatures in the 80s this weekend and
near 80 on Monday.

Late Monday afternoon and evening, models continue to show  a
slight chance for thunderstorms to develop in south-
central/eastern Siskiyou and Modoc Counties  due to some
increased mid level moisture, weak instability and an upper level
shortwave moving into the area. On Tuesday, the area of moisture
and weak instability shifts slightly further east into eastern
Siskiyou, Modoc County and far southeast Lake County. So have
kept the slight chance of thunderstorms for these areas.

Additionally, late Monday and Tuesday an upper level trough will
move into areas just to the north. This will flatten the ridge and
result in temperatures cooling a several degrees on Tuesday.
Additionally expect winds aloft to increase. As these winds mix
down during the afternoon, gusty west winds are expected,
especially for areas from the Cascades eastward Tuesday afternoon
and evening. This pattern continues on Wednesday with temperatures
cooling a few degrees further and continued gusty
afternoon/evening winds from the Cascades east.

For Thursday and Friday, there is lower confidence in the
forecast details as models show more variability with the details
of the pattern. Model solutions indicate that an upper low will
approach the central California coast but may remain offshore.
Meanwhile to the north a broad upper trough is in place while an
upper level ridge is centered offshore. Overall, expect near or
slightly above normal temperatures late next week with conditions
likely remaining dry.


&&

.AVIATION...For the 08/18Z TAF Cycle...VFR conditions will prevail
across much of the area through the TAF period. A narrow band of
marine stratus stretches just along the coast north of Cape Blanco.
This band could occasionally move inland and bring brief periods of
MVFR cigs to KOTH. However, the main concern will be moderate to
strong north winds that could reach 35 kts or higher this afternoon
and evening along the coast. Expect breezy to gusty winds for inland
areas as well. Winds will diminish shortly after sunset. /BR-y

&&

.MARINE...Updated 100 PM PDT Friday, 7 August 2020...The thermal
trough will remain strong along the coast through at least Monday
afternoon. This will continue to bring strong gusty north winds and
steep to very steep wind driven seas. Gales are expected south of
Port Orford this afternoon and early evening and again Sunday
afternoon and early evening. Warning level seas will spread north of
Cape Blanco this evening and most of the waters will experience very
steep and hazardous wind driven seas.

The thermal trough will move inland Monday afternoon with north
winds gradually diminishing, but gales are expected to linger
through Monday evening for the southern waters. Winds and seas will
continue to diminish Monday night into Tuesday, however, a weaker
version of the thermal trough is expected to remain along the coast
through much of next week. As a result, moderate to strong north
winds and steep wind driven seas are possible for much of next week,
especially south of Cape Blanco. At the very least, conditions
hazardous to small craft are possible with hazardous seas conditions
also possible for the southern waters. -Petrucelli/BR-y

&&

.FIRE WEATHER...Updated 200 PM PDT Saturday 8 August 2020...

A warming trend will peak on Monday. A thermal trough will deepen on
the coast tonight and Sunday with increasing east to northeast winds
with moderate to poor humidity recovery near and at the ridges in
fire zones 618, 619, western 620, and western 280. The poorest of
these moderate recoveries are forecast for Sunday night into Monday
morning.

A cutoff low is expected off the coast of Central California early
next week, with instability in northern California Monday and
Tuesday. The instability may extend into the southern part of zone
625 on Tuesday.

Gustier winds are possible Tuesday and Wednesday afternoon into the
evening east of the Cascades.
Sandler



&&

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

CA...None.

Pacific Coastal Waters...Small Craft Advisory until 11 PM PDT this evening for
     PZZ356-376.
     Gale Warning until 11 PM PDT Monday for PZZ356-376.
     Hazardous Seas Warning from 11 PM this evening to 11 PM PDT
     Monday for PZZ350-356-370-376.
     Small Craft Advisory until 11 PM PDT Monday for PZZ350-370.

$$

CC



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