509
FXUS66 KMFR 222147
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
247 PM PDT Tue Oct 22 2019

.DISCUSSION...A weakening front will move through the area late this
afternoon. As expected, most of rain from this front was along the
coast from Bandon north and northern Cascades. North Bend was the
bog winner with 0.25 of an inch of rain in 6 hours ending at 11 am
pdt. Since then, the front has basically dissipated and radar
returns are showing virtually nothing.

What we have left is plenty of cloud cover along and west of the
Cascades with more extensive cloud cover north of the Umpqua Divide,
but this should gradually thin out over time into early this
evening.

It will be dry tonight and will remain dry lasting through the end
of the week as upper ridging builds in. This will mean generally
clear skies and warmer than normal temperatures. This will be
especially true along the Curry coast where offshore flow and a
Chetco effect will set the stage for very warm weather Wednesday and
especially on Thursday. In fact high temperatures at Brookings and
Red Mound could get into the lower 80s Thursday. Currently we have a
high of 83 at Brookings on Thursday. If this pans out it could break
the old record of 83 degrees set back in 1982 It will be warm
elsewhere, as well, with temperatures likely around 10 degrees above
normal.

Another upper trough will ride over the ridge Friday afternoon and
night with another cold front dropping south into the area. The
trajectory of the upper trough is one that is not favorable for
precipitation in our area. With that said, the operational ECMWF and
a few of the individual ECMWF ensemble members hint at some QPF over
the northwest part of the forecast area. Right now we have a slight
chance of showers for parts of northern Douglas County and northern
Cascades Friday evening, but suspect we won`t get anything.
Depending on the timing of arriving cloudiness, Friday will probably
still be warm.

Behind the front will be much cooler air mass with a dry cool
northerly flow. It will be cool to col in the overnight hours with
the coldest temperatures at night east of the Cascades. However we
could have near freezing temperatures Sunday, Monday and Tuesday
mornings for most inland westside valley locations. Afternoon
temperatures will also be cooler, but milder in the westside
valleys. A thermal trough will set up once again along the coast
with breezy east to northeast winds along the coastal mountains in
southwest Oregon and mid slopes and ridges in western Siskiyou
County. -Petrucelli


&&

.AVIATION...For the 22/18Z TAFs...Areas of MVFR/IFR cigs and
local LIFR along the coast will continue into this evening, mainly
for areas north of Cape Blanco. MVFR cigs may become isolated in the
late evening due to drier north to northeast flow affecting the
area. However, confidence is only moderate on conditions improving
to VFR at the coast. May continue to see isolated IFR north of Cape
Blanco. Then chances for IFR increase along the coast north of Cape
Blanco early Wednesday morning, including at KOTH. So have added
this to the KOTH forecast.

Inland, expect VFR with areas of MVFR cigs in the Umpqua basin this
evening and areas of mountain obscurations from the Southern Oregon
Cascades west. Then overnight expect areas of IFR cigs and IFR/MVFR
vis to develop in the Umpqua basin continuing into Wednesday
morning, including at KRBG. East of the Cascades, isolated IFR
cigs/vis are also possible. Confidence is low on fog developing at
KLMT though. So will need to monitor this with future model runs.
Elsewhere, mainly VFR conditions are expected tonight into Wednesday
morning. -CC


&&

.MARINE...Updated 230 PM PDT Tuesday 22 October 2019...Quiet
conditions with swell dominated seas will continue through this
afternoon. A thermal trough develops today and strengthens this
evening, bringing the return of strong gusty north winds. Seas
transition to wind driven, becoming steep to very steep and
hazardous. Warning level seas are expected south of Port Orford late
tonight through Thursday with advisory level conditions expected for
most areas elsewhere. Conditions should improve briefly late
Thursday into Friday, but the improvement will be short-lived.
Hazardous conditions, possible gales, are likely to return late
Friday and persist into the weekend. Some improvement is possible
early next week when the thermal trough weakens, but confidence on
this improvement is only moderate. BR-y/Keene


&&

.FIRE WEATHER...Updated 100 PM PDT Tuesday 22 October 2019...A high
pressure ridge will build over the region tonight then strengthen
Wednesday into Thursday.  Also a surface thermal trough will set up
along the coast tonight and strengthen Wednesday into Thursday. This
pattern will bring breezy to gusty east to northeast winds to the
ridges tonight through Thursday night. Strongest winds are expected
Wednesday night and Thursday with gusts of 25 to 35 mph expected
over the mountains in Curry, western/southern Josephine, and western
Siskiyou Counties as well as in the Siskiyou Mountains. Poor to
moderate recoveries are also expected for the ridges Wednesday night
and Thursday morning. Additionally, breezy to gusty winds and
moderate to locally poor recoveries are also expected in the
Southern Oregon Cascades during this period. Daytime humidities
Wednesday and Thursday will also trend drier with inland areas
seeing humidities in the 15 to 25% range, except for higher values
in the Umpqua Basin.

Winds are forecast to lower Thursday night. Then on Friday, high
pressure will weaken over the region as a weak front moves inland to
the north. With the front, expect a slight chance for light showers
into north-central and northeast Douglas County. Otherwise, expect
dry weather across the area. As an upper trough moves down into
portions of eastern Washington and eastern Oregon on Saturday,
expect the high pressure ridge centered offshore to strengthen. With
this pattern, the surface thermal trough will rebuild along the
coast. This may bring a return of gusty east winds and poor to
moderate recoveries Saturday night into Sunday. However, also expect
cooler temperatures for most inland areas Saturday and Sunday.
-CC


&&

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

CA...None.

Pacific Coastal Waters...Small Craft Advisory from 11 PM this evening to 5 AM PDT Friday
     for PZZ350-356-370-376.
     Hazardous Seas Warning from 11 PM this evening to 2 PM PDT
     Thursday for PZZ376.

$$

NWS MFR Office Area Forecast Discussion