Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Medford or
900 PM PDT Friday Aug 22 2014
Discussion...a short wave disturbance will move through the County Warning Area
overnight on the back side of an upper low moving into Idaho. But,
the atmosphere is far too dry to produce any precipitation.
Overall, skies will be clear with some stratus/patchy fog
developing along the coast and in the coastal valleys north of
Cape Blanco. Wildfire smoke will continue to impact Siskiyou
County, but will tend to push toward south and west sections as
light to moderate offshore flow develops. Some smoke from the Sky
Lakes fire may also begin to drift southwest toward the Rogue
Valley tonight as winds aloft turn more northeasterly. The
forecast is on track this evening and no further updates are
Aviation...based on the 23/00z taf cycle...
in Siskiyou County...smokes will settle into the valleys and
middle slopes this evening through Saturday morning with local
visibility down to MVFR. Coos coast should see IFR conditions
returning between 05z and 17z. Elsewhere, VFR conditions will
persist for the next 24 hours. Spilde/fb
Marine...updated 755 PM PDT Friday 22 Aug 2014...the forecast was
updated earlier this evening to bring Small Craft Advisory winds
in closer across the southern inner zone. Buoy 27 was indicating
peak gusts to 33 knots earlier. Offshore high pressure and a thermal
trough inland will both strengthen over the weekend resulting in
gusty north winds and steep wind driven seas. The strongest winds
and steepest seas will be over the southern outer waters south of
Gold Beach each afternoon and evening through about Tuesday. There
is some uncertainty regarding wind strength through the weekend,
but winds are expected to remain below gale. With north winds
continuing for several days, have opted to issue a hazardous seas
watch for the southern outer waters beginning Saturday afternoon,
but much will depend on the strength and the extent of the
affected area as to how steep the seas may become. Spilde/fb
Previous discussion... /issued 100 PM PDT Friday Aug 22 2014/
Discussion...22/12z NAM/GFS in.
Stratus has burned off...leaving scattered stratocumulus behind.
Cumulus clouds are starting to pop on the ridges from the Cascades
east. There is also lots of smoke aloft emanating from several
fires in western Siskiyou County.
A long wave upper level trough remains over the Pacific northwest
this morning...with the trough axis running from British
Columbia...through eastern Washington and eastern Oregon...and
into extreme western Nevada. The Medford County Warning Area remains under west to
northwest flow aloft.
The trough will move east...but this will be a slow process due to
short waves diving down the backside of the trough. One such wave
will move through this afternoon and evening. It will be dry due
to its mostly overland trajectory and the main effect will be to
enhance offshore low level flow tonight.
Heights will rise Saturday as the trough moves out and onshore
flow will return Saturday night into Sunday. However...one more
strong short wave will dive down Sunday night...which will dig out
another trough over the Pacific northwest.
Once that trough moves out Monday the offshore long wave ridge
will build in in earnest...and this will kick off another heat
wave for the inland portions of the Medford County Warning Area. Offshore low
level flow will peak Monday night.
Expect continued dry conditions into the middle of the week. The
thermal trough will move inland Wednesday...and this will bring
the hottest temperatures of the week to the west side valleys.
Medford highs will flirt with the century mark Wednesday.
The upper ridge will slowly weaken around the middle of the
week...and the axis will break to the east of the area
Wednesday. The medium range models did diverge after
Wednesday...but the latest 22/12z run of the GFS is now in line
with the 22/00z ec solution. So...will go with continued weak
ridging with the axis well to the east of the County Warning Area and southwest
flow aloft. Expect continued dry weather with a slow cooling trend
inland from Thursday on. Temperatures will remain above normal
Pacific coastal waters...Small Craft Advisory for winds until 11 PM
PDT this evening for pzz356.
Small Craft Advisory for winds from 2 PM Saturday to 5 am PDT
Sunday for pzz350-356.
Hazardous seas watch from Saturday afternoon through Tuesday
afternoon for pzz356-376.
Small Craft Advisory for hazardous seas until 3 PM PDT Tuesday
Small Craft Advisory for winds from 2 PM Saturday to 11 am PDT
Sunday for pzz370.
Small Craft Advisory for winds until 11 PM PDT Tuesday for