Area Forecast Discussion
Issued by NWS Medford, OR

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FXUS66 KMFR 302116
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
216 PM PDT MON MAY 30 2016

.DISCUSSION...

.Short Term...Tonight through Thursday Night...Upper level
ridging and the thermal are combining to produce clear skies and
very warm temperatures, which should persist through nearly the
entire short term. THe warmest days of the short term will be
tomorrow and Wednesday, with high temperatures of 5 to 10 degrees
above normal along the north coast and up to 20 degrees above
normal along the south coast and for all areas inland. Newer model
runs have pushed up temperatures slightly in some areas, and this
has brought triple digit forecast highs to some localized areas in
the Klamath/Salmon valleys of western Siskiyou County and in the
Illinois valley in Josephine County. Other areas in the West Side
valleys could get really close to that mark as well. The thermal
trough will shift inland Wednesday, and while this will bring
cooler temperatures to the immediate coastline, there will be
little change otherwise, with the West Side on average slightly
cooler and the East Side slightly warmer. Thursday will be a near
clone of Wednesday, in terms of temperature, but onshore winds
later in the day should start a slight, although brief, cooling
trend heading into the extended.

Despite the warm temperatures and mostly clear skies, there is
the possibility for some convection to develop Wednesday
afternoon. Model solutions have backed off on the areal coverage
of precipitation, which is not unexpected given the lack of a
lifting mechanism over the past several runs. However, all of the
model suites are producing some very small areas of convection
Wednesday in the Mt Shasta to Medicine Lake region, probably more
due to terrain influences than any shortwave or other lifting
feature. Therefore, confidence remains low, but have kept the
slight chance of showers and/or thunder in the forecast for the
afternoon and evening Wednesday, with some modification of areal
coverage to more coincide with the latest model guidance. Thursday
should remain dry, aside from some light drizzle in the morning
along the coast north of Cape Blanco, as onshore flow encounters
the coastline. -BPN

.Long Term...Friday through Monday Night...Friday into the
weekend, models continue to show agreement that the ridge will
strengthen over the area while a closed low to the south gradually
moves inland into the central California coast. This pattern is
expected to bring warming temperatures to the area Friday and
Saturday. Peak temperatures are expected on Saturday with highs in
the 90s to near 100 in western inland valleys and in the upper 80s
to near 90 for valleys east of the Cascades.

For Sunday, the GEFS, GFS and ECMWF have trended further north with
the track of the closed low, bringing it into central to south
central California. This low is forecast to send southerly mid level
moisture into the area as well as shortwave activity. Although
temperatures are expected to be slightly lower on Sunday, compared
to Saturday, daytime heating will provide plenty of instability.
Have expanded the chance for thunderstorms over inland areas on
Sunday. Moisture, instability and shortwave activity continue
overnight Sunday into Monday morning so have kept a slight chance
for thunderstorms in during this period. On Monday, models show the
low gradually moving inland to the east-northeast into Nevada.
Continued moisture around this low will bring additional chances for
showers and thunderstorms to the area. Of note, the track of this
low remains the main factor in determining which areas will see the
best chance for thunderstorms and model ensemble solutions continue
to show variability with the track as it moves inland. /CC

&&

.Aviation...For the 30/18Z TAF cycle...VFR conditions will continue
at all TAF sites through the TAF period. Gusty and moderate to
strong north winds will develop this afternoon along the coast. -CC

&&

.Marine...Updated 825 AM PDT Mon 30 May 2016...Small Craft
conditions will continue south of Cape Arago  this morning with
gusty north winds, and seas dominated by both steep wind waves and
fresh swell. Winds will increase this afternoon and evening across
the waters with Gales in the southern portion of the outer waters
and Advisory strength winds over the remainder of the waters. North
winds will then gradually decrease but remain strongest in the
southern portion of the outer waters late tonight through the middle
of the week. Advisory conditions are likely to persist in the outer
waters through Wednesday night. -CC

&&

.Fire Weather...Next week will be warm and dry with a rapid warming
from Tuesday onward. Confidence is high that the valleys W of the
Cascades will see high temperatures in the 95 to 100 degree range as
the thermal trough shifts inland and remains W of the Cascades on
Tuesday and Wednesday. Expect minimum RH for western valleys to be
in the mid teens with fair to poor recovery Tuesday night and
Wednesday night. The thermal trough is expected to shift east of the
Cascades Wednesday but onshore push will be confined mainly to
Douglas County of Oregon.

Around Wednesday we will have to contend with thunderstorm chances
as southerly flow aloft strengthens and allows more moisture and
instability to spread north. Right now we see only the higher
terrain such as the Cascades/Siskiyous, Marble Mountains, the
mountains of the Fremont-Winema Forest being the most likely area
to see lightning strikes. Confidence is not high on how much rain
these storms will produce. By Friday instability appears to be
shunted to central California and we have removed thunderstorm
chance from the forecast. Hot temperatures inland will continue into
the end of the week. /FB


&&

.MFR Watches/Warnings/Advisories...
OR...None.

CA...None.

Pacific Coastal Waters...Small Craft Advisory until 11 PM PDT this evening for
     PZZ350-356-370-376.
     Gale Warning until 11 PM PDT this evening for PZZ376.
     Hazardous Seas Warning until 11 PM PDT this evening for PZZ376.

$$

BPN/CC/FB



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