FXUS66 KMFR 090534

Area Forecast Discussion
National Weather Service Medford OR
1034 PM PDT Wed Apr 8 2020

Updated AVIATION Section

.DISCUSSION...No big updates needed this evening. Did add some
patchy fog mention along the coast north of Cape Blanco for the
early morning hours. There may also be some patchy fog in the
Umpqua Basin again Thursday morning, but overall coverage is
expected to be much less.

High temperatures today were around 10 to 15 degrees warmer than
Tuesday`s highs. Brookings was actually 23 degrees warmer today
than yesterday! The Chetco Effect was in full swing today and this
resulted in a high temperature of 82 degrees this afternoon. The
rest of the area was slightly cooler, with upper 60s across the
east side and mid to upper 70s on the west side. These are the
warmest temperatures of the year so far, and it`ll be warmer
tomorrow by at least a few degrees. Brookings, however, should be
cooler considering that offshore flow (which leads to the Chetco
Effect) will be weaker. High temperatures will peak tomorrow, then
a cooling trend will follow over the weekend. For more details on
this, see the previous discussion below. /BR-y


.AVIATION...For the 09/06Z TAF Cycle...VFR conditions will prevail
through Thursday evening, except for areas of late night into early
morning MVFR/IFR cigs in low clouds in portions of the Umpqua Basin
and within the coastal valleys. Spilde/BR-y


.MARINE...Updated 830 PM PDT Wednesday 8 April 2020...Conditions
over the coastal waters will be dominated by a thermal trough near
the coast, with gusty north winds and steep to very steep wind-
driven seas persisting through the weekend. The trough will vary
slightly in strength, but conditions will not change much until the
pattern changes, possibly next week.


.PREV DISCUSSION... /Issued 236 PM PDT Wed Apr 8 2020/

DISCUSSION...Dry weather will continue through at least early next
week. Today and tomorrow will be the warmest days for most inland
locations, followed by slight cooling Friday into the weekend.

Skies are clear to partly cloudy over most of the forecast area. The
exception is in portions of Modoc County with some fair weather
cumulus clouds. Skies will remain clear tonight through Thursday

Tonight will be dry with offshore flow again resulting in breezy
winds near and at the ridges in the coastal mountains in southwest
Oregon, western Siskiyou county and Cascades.

Dry and warmer weather is expected Thursday away from the coast. In
fact portions of the Rogue, Illinois, Applegate and valleys in
Siskiyou County could see temperatures in the upper 70s to 80
degrees. East of the Cascades afternoon temperatures will be in the
lower 70s.

The thermal trough will weaken and move inland Thursday night and
this could result in marine stratus forming over the waters, along
the coast and inland, in portions of the Coquille Basin. For now we
don`t think the stratus will make it into the Umpqua Basin, but this
will have to keep a close watch on this.

Slight cooling is expected Friday with further cooling next weekend
as an upper trough moves southeast into northeast Oregon on
Saturday. Friday were still expecting afternoon temperatures in the
low to mid 70s in the Rogue, Illinois, Applegate, and upper 70s
in the Siskiyou County valleys. The weekend will be cooler, but
afternoon temperatures will still be above normal, just not as

Other than slight cooling on Saturday, the main affect from the
above mentioned upper trough swinging northeast of our area will
be gusty winds east of the Cascades. This is due to a combination
of a tighter pressure gradients, stronger winds aloft (700mb
winds between 40-45 kts) and max heating.

Dry northerly flow remains over the area through the start of next
week as the upper ridge axis shifts west. Afternoon temperatures
Sunday and Monday will be similar and still above normal away from
the coast. Gusty breezes, especially east of the Cascades are
expected in the afternoon and early evening hours.

The overall pattern won`t change much next Tuesday and Wednesday.
The operational models suggest stronger shortwaves could move down
from the north into our area, but there`s not enough over water
trajectory for precipitation. With that said the operational ECMWF
seems a bit bullish with the QPF field Tuesday night into
Wednesday. However, several of the individual ECMWF ensemble
members are showing no measurable precipitation. The forecast in
this time period will lean towards dry, but do have a slight
chance of pops in a few locations mainly in the north and
northeast part of our forecast area. -Petrucelli




Pacific Coastal Waters...Small Craft Advisory until 11 PM PDT Friday for
     Hazardous Seas Warning until 11 PM PDT Thursday for PZZ356-370.
     Small Craft Advisory from 11 PM Thursday to 11 PM PDT Friday for
     Hazardous Seas Warning until 11 PM PDT Friday for PZZ376.



NWS MFR Office Area Forecast Discussion