Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Medford or
840 PM PDT Wednesday Oct 1 2014
Discussion...just a few updates this evening. With lower dewpoints
on the far east side have adjusted low temperatures dwon closer to
the met guidance. Following the temperature/dew point trends for tonight verses
last night in the Shasta Valley have adksuted the low
tonight...mainly in northern potrions of the Valley...Down to the
range to include it in a frost advisory. The newest addition to the
frost advisory for this area has been issued.
Previous discussion...no weather of significance is expected in our
area over the next week or so, thus not many changes made to the
going forecast. A ridge centered along 140w continues to build this
afternoon with the axis becoming centered along the U.S. West
Coast by Friday and remaining there through at least early next
week. The ridge flattens out around middle next week and then
moisture and energy begin flow into the pacnw to our north. Some
energy is even shown digging in to our south. Such a split flow
would also be dry for US. Model consistency next week isn't that
great, so confidence is lower the further out we get. For the
short term and into early next week, though, confidence is high
(certain, really) that mostly clear skies will prevail for the
majority of our area and there will be no precipitation.
Clear skies will lead to another cool to cold night over SW Oregon
and northern California inland from the coast tonight. Forecast
lows for tonight are similar to what we saw last night, and this
means another round of frost advisories and freeze warnings for
east side locations. On the west side, valley inversions will
become strong overnight as the subsidence inversion aloft
descends. This will result in warmer and drier conditions over
the ridges. However, offshore flow is expected to be a touch
weaker, so we're not expecting any red flag conditions. Areas of
stratus will probably reform along the north coast and into the
Umpqua late tonight into early tomorrow.
The airmass warms and dries tomorrow as the ridge axis gets
closer. Then temperatures get rather warm for October Friday
through the weekend into early next week as the ridge moves
overhead. Highs will be in the 80s on the west side (perhaps 90 at
medford) and 70s east of the Cascades through the period, which
is roughly 5-10 degrees above normal. -Wright
Aviation...for the 01/18z taf cycle...VFR conditions will continue
for the next 24 hours. The exception will be in the Umpqua basin
where low clouds are expected to develop resulting in MVFR/IFR ceilings
at krbg towards daybreak. -Petrucelli
Marine...updated 2 PM PDT Wednesday 1 Oct 2014...high pressure offshore
with a thermal trough at the coast will maintain gusty north winds
through Thursday. Gales the next two afternoons and evenings are
expected beyond 10nm from shore south of Cape Blanco with moderate
winds elsewhere...except for areas within 2 nm from shore where
winds should remain below Small Craft Advisory criteria. Steep to
very steep seas will affect most of the waters. Then on Friday high
pressure will weaken as a cold front passes to the north...causing
north winds and seas to lower for a brief time. The thermal trough
will redevelop on Saturday...and winds and seas will increase. Gales
are not expected over the weekend...but high end Small Craft
Advisory conditions will impact waters south of Cape Blanco beyond
10nm from shore. Sk
or...frost advisory from 1 am to 8 am PDT Thursday for orz029>031.
Freeze warning from 1 am to 8 am PDT Thursday for orz029>031.
California...frost advisory from 1 am to 8 am PDT Thursday for
Freeze warning from 1 am to 8 am PDT Thursday for
Pacific coastal waters...Small Craft Advisory for winds until 5 am
Friday for pzz350-356-370-376.
Small Craft Advisory for hazardous seas from 5 PM this
to 11 PM PDT Thursday for pzz350-370.
Small Craft Advisory for hazardous seas until 11 PM PDT
Gale Warning until 11 PM PDT Thursday for pzz376.
Hazardous seas warning until 11 PM PDT Thursday for pzz376.