Wildfire in Oregon, October 1 to 2, 2016

Area Forecast Discussion...Updated
National Weather Service Pendleton OR
425 AM PDT SAT OCT 1 2016

Updated aviation discussion

.SHORT TERM...Today through Monday Night...Latest satellite
imagery shows upper level low pressure continues to rotate
offshore the WA/OR coast...with a weak wave exiting eastern OR.
Radar/observations show isolated/widely scattered showers
extending from the Blue Mountain foothills eastward. The wave will
continue to exit to the east early this morning...with residual
isolated showers diminishing. With most of the area in between
impulses...dry conditions can be expected. The exception will be
along the east slopes of the Cascades where showers will increase
in coverage by this afternoon as the low nudges closer to the
coast. The cooling trend will continue today...with highs in the
upper 60s/around 70 for the lower elevations...with mid 50s to
mid 60s mountains. Snow levels will fall to 5500-6500 feet. The
low will move south along the Oregon coast tonight. With little
east movement of the low...do not expect precip to move much
further inland from the Cascade crest so will keep areas east of
the Cascade east slopes mainly dry. Lows tonight will range from
the upper 30s/lower 40s for the lower elevations...with mid 20s to
mid 30s mountains.

Sunday/Sunday Night...Models in general agreement bringing the
low onshore the SW Oregon coast by Sunday afternoon...then
swinging the low SE across extreme northern CA/NV Sunday Night.
Given this trajectory...precip chances will increase east of the
Cascades Sunday afternoon...with the greatest increase across
Central Oregon...where high end chance to likely PoPs will be
used. Precip will begin to decrease by late Sunday night as the
low moves to the east. Highs Sunday will be 1-3 degrees cooler
than Saturday...with lows Sunday Night a few degrees milder due to
increased cloud cover.

Monday/Monday Night...The low will move into southern MT/WY...with
brief low amplitude ridging crossing the area. Dry and seasonably
cool conditions can be expected Monday. Precip chances will
increase Monday Night across the Cascade east slopes and Central
Oregon as the next trough is progged to enter the Pacific
Northwest.

.LONG TERM...Tuesday through Saturday...Models agree in having
a northwest flow over the area Tuesday through Wednesday. A
disturbance will move through the area though models have timing
differences. The GFS brings in showers Tuesday while the ECMWF holds
it back until Tuesday night. Have leaned towards the GFS and have a
chance of showers in the mountains and a slight chance of showers
elsewhere Tuesday and Tuesday evening. Winds will be breezy in the
Columbia Basin Tuesday afternoon and early evening. Tuesday evening
and Wednesday the lower elevations dry out and the mountains
continue to have a slight chance of showers. Rain amounts look to be
around a tenth of an inch in the lower elevations and up to a
quarter inch in the mountains. Snow levels will be around 6500 feet,
so the higher mountains could get an inch or two of snow. Wednesday
night and Thursday morning a transitory ridge crosses the area for a
brief dry period. By Thursday afternoon, both the GFS and ECMWF have
a trough moving into the area and it will cross the area through
Friday night. The GFS is wetter through this period and have leaned
towards it again as the ECMWF looks too dry. Thursday night through
Friday night will have a chance of rain in the mountains and a
slight chance in the lower elevations. Saturday the trough will be
departing to the east while a ridge tries to build over the area.
Lingering showers will keep a slight chance of light rain over the
area on Saturday with a chance of rain from the Northern Blue
Mountains eastward. Temperatures will remain unseasonably cool with
highs in the 60s with 50s and lower 60s in the mountains. Lows will
be in the 40s with upper 20s and 30s in the mountains. Perry

&&

.AVIATION...12Z TAFs...Skies will be scattered to broken above 7000
feet AGL this morning becoming few to scattered this afternoon.
Skies will begin increasing back to scattered to broken after 06Z.
An exception will be KDLS which VCSH with scattered ceilings around
5000 feet AGL from 15Z-20Z this morning. Otherwise precipitation
chances were too low to mention. Winds will reach 10 to 15 kts with
gusts to 25 kts at KRDM, KBDN, KPDT and KPSC this afternoon.
Otherwise winds will remain below 15 kts for the next 24 hours. Perry

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  68  41  65  44 /  10  10  10  10
ALW  70  44  68  47 /  10  10   0  10
PSC  72  43  71  47 /  10   0   0  10
YKM  72  38  72  40 /  10  10  10  10
HRI  72  38  71  44 /  10   0   0  10
ELN  68  37  68  40 /  20  20  10  10
RDM  66  28  59  30 /  10  10  30  30
LGD  67  35  67  39 /  10  10  10  10
GCD  64  33  65  37 /  10  10  10  10
DLS  71  45  70  48 /  20  10  20  10

&&

.PDT Watches/Warnings/Advisories...
OR...None.
WA...None.
&&

80/83/83