Area Forecast Discussion
Issued by NWS Medford, OR
FXUS66 KMFR 232244
Area Forecast Discussion
National Weather Service Medford OR
345 PM PDT SAT JUL 23 2016
.Updated fire weather discussion.
.DISCUSSION...23/12Z NAM/GFS/EC in.
Mostly clear skies this afternoon over the Medford CWA...except
for some marine stratus well offshore.
Flow aloft remains nearly westerly this afternoon. The upper
level pattern will alternate between weak zonal flow and weak
troughing through Wednesday...with little in the way of short wave
activity over our area. The ridges of the coast range will be dry
and breezy during the overnight hours due to low to moderate...but
persistent...easterly low level flow. Stronger winds have returned
to the coastal waters due to the strengthening thermal trough.
Temperatures will warm through Monday. Highs in the Umpqua Basin
will warm to near normal values by Sunday...and inland highs over
the remainder of the area will warm to 5 to 10 degrees above
normal. High temperatures will warm around 5 degrees or so over
the west side and northern California Monday through
Wednesday...but only a degree or two over the east side during
Upper level ridging will build in more strongly Wednesday into
Thursday...bringing hotter temperatures to the area. Inland highs
Thursday will warm to 5 to 10 degrees above normal over Oregon and
10 to 15 degrees above normal over northern California.
The ridge will begin to weaken Thursday into Friday as short waves
embedded in the westerly flow move through...but inland
temperatures will keep on warming through at least Friday...when
the highs will be 10 to 15 degrees above normal.
The ridge will weaken further Saturday as more short waves move
through. Inland temperatures will cool a few degrees. The 23/12Z
EC is advertising dry conditions for that day while the 23/12Z
GFS model run indicates the possibility of afternoon and evening
thunderstorms...which is consistent with the GFS/EC 22/12Z
solutions. Therefore...have added afternoon/evening thunderstorms
to the forecast for next Saturday...but there is still a lot of
uncertainty this far out.
.AVIATION...23/18Z TAF cycle...Low level northerly winds at the
coast will become strong this afternoon and evening with local gusts
to 35 KT. A slightly less extensive intrusion of low clouds into
Coos and Douglas Counties is expected late this evening into Sunday
morning. Roseburg should remain clear tonight with a slight
potential for MVFR ceilings early Saturday morning. North Bend is
more likely to have MVFR conditions in the early morning, but these
should only last for several hours before clearing to VFR. Skies
will remain clear elsewhere through Sunday. DW/SK
.MARINE...Updated 900 AM PDT Saturday 23 July 2016...High pressure
offshore will strengthen and a thermal trough will deepen over
northern California today then remain strong much of next week.
This will result in an extended period of strong north winds and
steep, hazardous seas. Winds will be strongest and seas will be
steepest during the afternoons and evenings beyond 10 nm from shore
south of Cape Blanco. Gales are expected in that area with small
craft advisory conditions over the remainder of the waters. With
excellent run to run consistency in the GFS, ECMWF and latter
portion of the NAM, the gale watch that was in effect for next week
has been upgraded to a gale warning. DW/SK
.FIRE WEATHER...Updated 300 PM PDT Saturday 23 July 2016.
It will be hot and dry through the next week. Breezy north winds are
expected west of the Cascades today and tomorrow while East Side
winds will be relatively light with typical afternoon breezes. A
Haines Index of 6...indicating very dry and unstable conditions...is
expected east of the Cascades. Areas west of the Cascades will
feature a Haines Index value of 5, with more stable conditions
compared to the East Side. A long-duration surface thermal trough
will bring periods of breezy northeast overnight winds and moderate
humidity recoveries through Thursday at the coast and in Western
Siskiyou County. Moderate humidity recoveries are also expected east
of the Cascades through Thursday. Lastly, weak instability may
develop on Saturday, and a slight chance of thunderstorms has
been introduced into the forecast. SK/DW
Pacific Coastal Waters...Small Craft Advisory until 5 AM PDT
Thursday for PZZ356-376.
Small Craft Advisory for hazardous seas until 2 PM PDT this
afternoon for PZZ356-376.
Small Craft Advisory until 5 AM PDT Thursday for PZZ350-370.
Gale Warning until 5 AM PDT Thursday for PZZ376.