Area Forecast Discussion
Issued by NWS Spokane, WA
FXUS66 KOTX 271133
Area Forecast Discussion
National Weather Service Spokane WA
433 AM PDT Sat Aug 27 2016
A strong cold front is expected to bring gusty winds today and
heighten wildfire concerns. Limited shower chances arrive to the
northern mountains through early next week, with mild
temperatures, before a slightly better and broader threat of
showers and thunderstorms comes in for the second half of next
week. Temperatures cool toward or slightly below normal toward the
middle to latter part of next week.
Today through Sunday: The flow aloft will become moister and
flatten with time as an area of low pressure drops across BC today
and into Alberta. A surface low will accompany this feature and
drag a mostly dry cold front south of the Canadian border across
eastern Washington into north Idaho. Instability will be minimal
and lightning is not likely, although the lift from the passing
front may be enough to generate light showers or sprinkles over
the northern mountains through the day. Otherwise expect dry
conditions. The main weather concern will be winds. Currently the
Vad Wind profiler on the radar shows a westerly winds of 25 kts at
the first level, which corresponds well with model soundings of
increased winds right above the low level inversion. Winds will
steadily increase and mix to the surface through the day as the
front slides through the region. The strongest winds look to be
across the Columbia Basin with 10 to 20 mph and gusts to 30 mph.
Relative humidities will lower to critical levels especially
across the eastern Basin, Spokane area, Palouse and surrounding
mountain valleys of northeast Washington and the central Idaho
panhandle, which supports the Red Flag Warning in effect for this
afternoon and evening. The wind coupled with the dry conditions
will raise fire concerns on increased growth of any local fires.
Temperatures will be warm, climbing a couple degrees over Friday`s
readings ahead of the front across the eastern portions of the
forecast area, meanwhile some cooling will bring over the Cascades
in central Washington. This cooling will spread across the region
tonight with increased cold air advection and lighter winds.
Sunday will be slightly cooler as well under westerly flow aloft.
Some afternoon gusty winds are possible, not at the caliber of
Saturday and humidities will be slightly elevated. It should be a
dry day with more high level clouds. /rfox.
Sunday night through Saturday...Interesting pattern setting up as
a deep low pressure system currently in the northern Canadian
Plains retrogrades back to the west and merges with a low that is
currently in the Bering sea. This will carve out a pretty deep
trough off the B.C. coast Monday and allow these two low pressure
systems to dumbbell around each other. One wave will eject off the
main low around Tuesday with the main upper low finally moving
inland Friday and Saturday. Numerous weaker waves will also calve
off the main low between the one on Tuesday and the trough over
the weekend. This will keep an unsettled weather pattern across
the region through the extended period.
Sunday night through Monday night...High pressure will build over
the Inland Northwest ahead of the incoming upper low. The
resultant south-southwest flow will allow temperatures to rebound
by quite a bit from Sunday with temperatures well into the 80s and
lower 90s. Winds will remain out of the southwest but mainly less
than 10 mph. South-southwest flow will also tap into a bit more
moisture, but at this time it looks like just a better chance for
afternoon cumulus build ups.
Tuesday...A short wave disturbance will move through the region
Tuesday afternoon and evening. Not a lot of moisture to work with
but there will be enough along with afternoon heating to generate
some showers across the Cascades and the northern mountain late in
the day. Any showers will be light and spotty. Temperatures will
be slightly cooler.
Wednesday and Thursday...The 00z guidance is showing the flow
splitting Wednesday and Thursday as another weather disturbance
moves through the region. Moisture across the region does increase
allowing the atmosphere to destabilize, but with the flow
splitting it is hard to get excited about any widespread showers
or thunderstorms. Pops were backed off slightly through this
period with the focus across the higher terrain. Temperatures will
continue on a cooling trend.
Friday and Saturday...Model guidance wants to finally bring the
trough inland, but is also showing the flow splitting. If this
indeed does happen it would open the door for cooler temperatures,
breezy winds, and a chance for showers and thunderstorms, just not
very widespread. As such confidence in any one place receiving
measurable precipitation is rather low. More confidence in the
cooler temperatures, breezy winds and variable clouds. Stay tuned.
12Z TAFS: High cirrus will persist through the morning hours ahead
of a cold front moving down from the north. Patchy smoke will be
around the fire sources this morning with the light winds. Winds
will quickly increase through the morning hours with good mixing
and gusts increasing from 20kt to 30kt in the afternoon. Areas of
blowing dust will be across the Columbia Basin and head toward the
KGEG-KCOE area and KPUW but confidence on visibility restrictions
is low, as is the amount of smoke that will be generated. The
strongest winds look to be near KEAT with gusts to 34kt These
strong winds will start to decrease around 04Z, but still remain
elevated. VFR conditions are expected despite the high clouds. A
few mountain showers are possible near the Canadian border. /rfox.
.PRELIMINARY POINT TEMPS/POPS...
Spokane 86 56 80 59 88 61 / 0 0 10 0 10 10
Coeur d`Alene 85 54 79 55 88 56 / 0 0 10 0 10 10
Pullman 86 55 81 52 88 53 / 0 0 10 0 0 0
Lewiston 93 65 89 62 95 62 / 0 0 10 0 0 0
Colville 85 51 81 50 89 52 / 10 10 10 10 10 10
Sandpoint 81 51 77 50 85 51 / 10 10 10 10 10 10
Kellogg 83 52 78 52 87 54 / 0 0 10 10 10 10
Moses Lake 91 58 85 56 90 57 / 0 0 0 10 0 0
Wenatchee 87 60 83 63 89 62 / 0 0 0 10 0 10
Omak 88 55 84 56 90 56 / 10 0 10 10 10 10
ID...Red Flag Warning from 1 PM this afternoon to 9 PM PDT this
evening for Northern and Central Idaho Panhandle (Zone 101).
WA...Red Flag Warning from 1 PM this afternoon to 9 PM PDT this
evening for East Washington Northeast (Zone 686)-East
Washington Northern Columbia Basin (Zone 673)-East
Washington Palouse and Spokane Area (Zone 674).