Area Forecast Discussion
Issued by NWS Medford, OR

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FXUS66 KMFR 010000
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
500 PM PDT TUE MAY 31 2016

.SHORT TERM...Tonight through Friday Night...Upper level ridging
and the thermal trough are combining to produce clear skies and
very warm temperatures. Today should be the warmest day, with some
slight cooling on the West Side tomorrow as the thermal trough
shifts inland ahead of a weak system that will pass just to our
north. The East Side will see very similar temperatures tomorrow
as today, then will get their turn at a brief cooldown Thursday.
On Friday, ridging will build in behind the departing system, the
thermal trough will reform, and hot temperatures will make their
return to the forecast area.

During the warmer periods, when easterly surface winds are at
their maximum, overnight lows will not be all that low over the
ridgelines and higher terrain. This will also lead to low
humidities and poor overnight recoveries. More on this will be
available in the Fire Weather discussion below.

As for precipitation, there remains only one day in the short
term with any noticeable chances. This will be Wednesday, and only
for the areas around the Trinity Alps, Mount Shasta, and Medicine
Lake. While instability is present in all model suites, there is
no shortwave or other lifting mechanism that would produce
widespread convection. However, low level winds in the Central
Valley will be from the south during the afternoon and evening,
and these will be at direct opposition to the more northerly winds
over Oregon. The resulting convergence in the lower levels may be
enough to touch off some showers or even some thunder, so have
kept a slight chance in these areas to account for the
possibility. Otherwise, only a few light sprinkles along the north
coast on Thursday morning will break the overall dry trend as we
head into the extended period. -BPN

.LONG TERM...Saturday Morning, June 4th Through Tuesday, June 7th...
We expect record high temperatures to be broken at most locations,
on or about Saturday and, possibly, Sunday. The GFS based guidance
indicates hotter conditions Sunday than Saturday, whereas the more
favored ECMWF does the opposite. On Sunday, thunderstorms will be
possible from about the Cascades and Siskiyous south and eastward.
This threat will continue on Monday, possibly drifting a bit
westward, but the bulk of the thunderstorm activity appears as if it
will remain cascades and siskiyous south and eastward as of now.
Model guidance does not show sufficient wind to bring thunderstorms
to the west side, currently. Thereafter, the thunderstorm threat is
expected to do its normal drift eastward with time. By Sunday we
expect that fuel conditions will yield some concerns for new fire
starts, but will be checking in with fire agencies to see how much
of a concern that is as time gets closer and forecast details likely
become clearer. -BTL

&&

.AVIATION...For the 01/00Z TAF cycle...
Just some high clouds are expected for most locations over the
next 24 hours. Coastal areas from Reedsport to Cape Blanco are
likely to see some IFR to MVFR stratus overnight into the morning
in the 06z-18Z time frame...but conditions will improve to VFR by
mid-late morning. -Spilde

&&

.MARINE...Updated 2 PM PDT Tue 31 May 2016...Offshore high
pressure and a thermal trough along the coast will continue to
produce gusty north winds this week with short period wind waves and
fresh swell continuing to dominate the waters. Winds will be
strongest and seas will be highest beyond 3 nautical miles from
shore south of Cape Blanco. Winds will trend lower Wednesday night
and then will be at a minimum on Thursday. North winds are likely to
increase again Friday into the weekend. -Spilde

&&

.FIRE WEATHER...Updated 245 PM PDT Tue 31 May 2016...
We will begin our full suite of fire season products beginning
tomorrow, June 1st. June will begin with a heat wave, which is a few
days ahead of record heat that was observed in early June just last
year. Currently, however, we expect records to be broken on just one
day at most locations- probably on or about Saturday for most sites.
There will be a slight threat of thunderstorms from the Trinity Alps
east-northeast to the Modoc Plateau tomorrow afternoon/evening.
Otherwise, we`ll be in the heat until Sunday, when thunderstorms
will be possible from about the Cascades and Siskiyous south and
eastward. This threat will continue on Monday, possibly drifting a
bit westward, but the bulk of the thunderstorm activity appears as
if it will remain cascades and siskiyous south and eastward as of
now. Thereafter the thunderstorm threat is expected to do its normal
drift eastward with time. By Sunday we expect that fuel conditions
will yield some concerns for new fire starts, but will be checking
in with fire agencies to see how much of a concern that is as time
gets closer and forecast details likely become clearer. -BTL

&&

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

CA...None.

Pacific Coastal Waters...Small Craft Advisory until 5 AM PDT Wednesday
     for PZZ356-376.
     Small Craft Advisory for hazardous seas until 2 AM PDT Thursday
     for PZZ356-376.
     Small Craft Advisory for hazardous seas until 5 AM PDT Wednesday
     for PZZ350-370.

$$

MAS/BPN/BTL



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