Wildfire in Oregon, October 1 to 31, 2018

Area Forecast Discussion
National Weather Service Medford OR
829 PM PDT Sun Sep 30 2018

.SHORT TERM...This evening, clouds have cleared for most inland
areas with mid level clouds located along the coast and inland
into the coastal mountains and into portions of Joesphine county.
Expect little if any showers tonight. On Monday, as a shortwave
off Vancouver Island moves south and a low off the California
coast near 35N/135W moves towards the California coast, expect
increased moisture transport from the west and southwest. Showers
are expected to to spread into the area during the day Monday.

Models are in good agreement with isolated to scattered light
showers moving into the area during the morning, with best chances
along the coast and into Siskiyou County. Shower activity will
increase during the day Monday as the upper level systems move
into the region. So, have increase the chance for precipitation
on Monday afternoon for areas from the Cascades west. Showers may
linger into Monday evening, then decrease in coverage overnight
Monday as the shortwave trough remains centered to the north and
the low is centered to south of the central California coast.
Expect the best chance for showers to be over Siskiyou county on
Monday night as moisture wraps around the low and moves up from
the south.

Temperatures are expected to remain mild on Monday with highs near
70 for west side valleys and in the 60s across valleys east of the
Cascades and for coastal areas. Of note, overnight lows tonight
may dip in the lower 30s for some valleys east of the Cascades due
to periods of clearing skies tonight. West of the Cascades expect
lows overnight tonight in the 40s to lower 50s. Patchy fog is
possible in inland valleys across the area tonight as well due to
recent moisture and partially clear skies.

&&

.AVIATION...For the 01/00Z TAFs...Overall, VFR conditions will
continue through this evening, with some localized areas of light
showers and MVFR possible through this afternoon. Tonight, MVFR/IFR
conditions in fog and low clouds are expected along the coast and
into the coastal valleys, and some areas of lower flight conditions
may spread into the Umpqua Basin by early morning. Elsewhere, VFR
conditions will continue overnight. -BPN/BR-y

&&

.MARINE...Updated 800 PM PDT Sunday 30 September 2018...South winds
will continue over the coastal waters due to low pressure residing
well offshore of the Pacific Northwest. A cold front will pass
through the region Monday, producing periods of moderate to heavy
rain and significant drops in visibility, but winds and seas should
remain well below small craft advisory levels. Following the frontal
passage, winds will shift to the north for much of the week, with
the exception of a few weak fronts that will produce brief periods
of south or west winds. Gusty north winds are expected to return by
next weekend as the thermal trough re-establishes itself along the
coast. -BPN/BR-y

&&

.PREV DISCUSSION... /Issued 226 PM PDT Sun Sep 30 2018/

DISCUSSION...Showers have just about ceased and we're seeing blue
skies in the breaks between clouds over most of the region. Cloud
cover should diminish a bit more through the rest of the day. Lows
tonight should be a fair amount cooler than last night due to
the lack of precip expected tonight, and lower cloud cover. Clouds
should dissipate most readily east of the Cascades, thus expect
overnight lows to be around 10 degrees colder than last night.

Monday, a low will swing down from the Gulf of Alaska and phase
with a low approaching the central California coast. While the
heaviest precipitation will likely be directed towards northern
Washington and central California, a surface trough along the lows
should support shower development Monday into Tuesday. Tuesday
into Wednesday, a secondary low will shift southeastward from the
west coast of British Columbia towards the northern Rockies. While
models are light on precipitation, expect deformation between the
two lows to strengthen uplift, thus went with a bit higher PoP
forecast than model solutions depict for Tuesday into Wednesday.

Another trough will swing into the PacNW late Wednesday into
Thursday, bringing another chance for a round of showers. A ridge
will start building in late Thursday into Friday, and conditions
should trend a bit drier. That said, there's indication that a weak
wave will ride over the top, bringing potential for some
precipitation Friday. Models continue to show an inside slider
dropping down Sunday into Monday, bringing a slight chance for
precipitation Saturday, primarily east of the Cascades...then in the
Sunday to early next week time frame, conditions are trending much
cooler east of the Cascades as Arctic air pushes south/southwestward
from the Canadian Rockies.

FIRE WEATHER...Updated 130 PM PDT Sunday, 30 September 2018...Cool
conditions are being observed across the forecast area, and humidity
has increased significantly compared to yesterday. Current humidity
values are 20 to 40 percent higher than 24 hours ago.

There's good agreement among the models showing another disturbance
bringing rain to parts of the forecast area on Monday. Confidence is
increasing that rain will affect at least the coast and Coast Range
and Siskiyou County, mainly from Cape Blanco southward. Wetting rain
doesn't look likely over the Klondike Fire, however, based on the
latest consensus of model data. Rains are also possible further
inland, but this should be short-lived as the upper low draws
moisture away from the area as it moves southward Monday night.

On Tuesday, most of the precipitation should be south of the
forecast area, though we can't rule out a few showers. Gusty winds
are expected east of the Cascades on Tuesday afternoon as the
forecast area feels the effects of an upper trough moving inland to
the north.

The next chance for significant rain is on Thursday as a cold front
moves from west to east across the forecast area. Right now the
models suggest the bulk of the showers will affect Northern
California and areas east of the Cascades. Keene

&&

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

CA...None.

Pacific Coastal Waters...None.

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