Area Forecast Discussion
Issued by NWS Spokane, WA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

407
FXUS66 KOTX 292209
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
309 PM PDT Tue Sep 29 2020

.SYNOPSIS...
High pressure will be anchored over the West this week bringing
our region a prolonged period of warm and dry weather. Temperatures
will be above average through the weekend. Afternoon highs in the
upper 70s to low 80s will be common from Tuesday through Sunday.

&&

.DISCUSSION...

Tonight through Thursday night: Ridge of high pressure remains in
place with low level thermal ridge positioned over the west coast
poised to start moving into the interior Wednesday. This positioning
of the low level thermal ridge will allow for low level winds to
tend to favor blowing from the east toward the thermal ridge.
Elevated smoke plume generated by very active California wildfires
is expected to drift up and over into Eastern Washington Wednesday
and linger through Thursday. The subsidence inversion brought about
by this stationary ridge will limit mixing from the surface up to
only about 2-3 thousand feet AGL for the workweek. This means
lowland locations will not mix high enough into the atmosphere to
bring this lofted smoke down to the surface which should keep it
from becoming a concern when it comes to air quality. One subtle
exception will be higher elevations, at above five thousand feet MSL
and higher which may notice a bit more smoke. Otherwise little in
the way of cloud cover is expected with this persistent ridge and
its accompanying warm temperatures. /Pelatti

Friday through Tuesday: The models are in good agreement with
this period. It is expected to not be impactful with unseasonably
warm temperatures and  The ridge pattern is expected to last through
Saturday. Smoke  from the California wildfires is expected to drift
up the coast and across the region. THe smoke is expected to be
mainly in the upper levels. A mid level inversion will keep the
smoke from reaching the surface and make for hazy conditions. A Low
will slide into the Northern part of the Gulf of Alaska and swing a
dry trough through the region on Sunday and bring a Northwesterly
upper level flow pattern. Winds will increase slightly but only
reach into the mid teens for gusts. It will help clear some of the
haze and smoke out the area but bring little relief to the warm
temps. Next chance of any precip for the region is expected to be
toward the end of next week. Temperatures for the period will range
in the upper 70s and 80s for highs and the 40s and low 50s for
lows. /JDC

&&

.AVIATION...
00Z TAFS: High pressure will keep light winds mainly from the
northeast over the aviation area with little in way of cloud
cover, however elevated smoke from very active fires in California
is expected to drift over the aviation area. It has been coded
generally as residing more or less near 10K feet AGL as a
scattered deck and making an appearance near KEAT around 8Z then
spreading east and remaining more or less overhead into Thursday.
Additionally some burning in Central Idaho has produced smoke that
could drift near KPUW and KLWS as a lower deck which is coded
lower in elevation at roughly 4K Feet AGL as a scattered deck near
KPUW and KLWS with some potential for the visibility to go down
to 6 miles for smoke/haze from that source of smoke in Central
Idaho. /Pelatti



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        45  78  46  77  48  78 /   0   0   0   0   0   0
Coeur d`Alene  46  78  46  76  49  77 /   0   0   0   0   0   0
Pullman        43  79  44  78  46  79 /   0   0   0   0   0   0
Lewiston       51  84  52  83  54  83 /   0   0   0   0   0   0
Colville       40  81  41  80  43  82 /   0   0   0   0   0   0
Sandpoint      43  75  42  72  44  75 /   0   0   0   0   0   0
Kellogg        49  77  51  76  53  77 /   0   0   0   0   0   0
Moses Lake     44  81  46  82  49  81 /   0   0   0   0   0   0
Wenatchee      53  81  58  82  59  81 /   0   0   0   0   0   0
Omak           49  81  54  83  54  82 /   0   0   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.

&&

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.