Area Forecast Discussion
Issued by NWS Spokane, WA
FXUS66 KOTX 010909
Area Forecast Discussion
National Weather Service Spokane WA
209 AM PDT FRI JUL 1 2016
Our weather will continue to be warm through the holiday weekend,
but we will be gradually be returning closer to normal by Sunday
and Monday. A series of weak cold fronts are expected to produce
periods of breezy weather through the Fourth of July. Isolated
mountain thunderstorms will be possible Saturday, but the majority
of the region will remain dry through early next week.
Today through Saturday night...As of 2 am Infrared Satellite
indicated an upper trough moving into British Columbia with a band
of mid and high clouds nearing the Washington coast. Models show
this band of mid and high clouds reaching Central and NE
Washington late this morning into the afternoon before dropping
into SE Washington and the Idaho Panhandle overnight into Saturday
morning. Models show no precipitation with this feature with dry
conditions expected through Saturday morning. Then Saturday
afternoon a weak short wave tracks into the Idaho Panhandle in the
afternoon. While weak...it will be passing through during peak
heating with general model consensus suggesting around 300-700
J/KG of surface based CAPE and little convective inhibition. Thus
POP`s have been increased to chance to account for this. Isolated
showers and thunderstorms are also possible for the northern
mountains. This wave exits early Saturday evening with dry
conditions likely for the remainder of the night.
The continued westerly flow will lead to an enhancing cross-
Cascade pressure gradient into Saturday with locally breezy winds
through the Cascade gaps mainly during the evening hours.
Relative humidity values should however remain above critical
values for fire highlights. JW
Sunday through Wednesday...
An upper trough over western Canada will drive the weather for
the Inland Northwest through mid week. The center of the low will
dip into central BC Sunday morning with a large piece of energy
wrapping around its base. This will lead to continued instability
over the northeastern mountains of our domain Sunday afternoon.
Just north of the border, both the GFS and EC are showing
widespread showers and thunderstorms under the cold core of the
upper low. But our area of concern will just see scattered
activity in the late afternoon and evening hours.
A possibly more substantial story will be the tightening gradient
along the Cascades. This is a result of high pressure building
over the eastern Pacific while the surface pressure deepens over
southern Alberta. Winds through the Cascade gaps will increase
Sunday afternoon and continue to be quite breezy through mid week.
The obvious concern with gusty winds in early July is that it will
lead to elevated fire danger. Temperatures will be near, if not
slightly below, normal for this time of year. It looks like right
now that the typical breezy spots along the eastern Cascades will
be flirting with red flag criteria...something we`ll have to watch
closely over the next few days.
Besides the fire danger over east slopes of the Cascades, the
remainder of the region will be breezy with temperatures slowly
warming back into the mid 80s. The next substantial wave to move
through will be Wednesday afternoon. While both the EC and the GFS
agree on the timing of the wave traversing the region, the GFS is
suggesting this will be a closed low with quite a bit of energy
associated with it. Because of that, the GFS solution has much
more precipitation and widespread cloud coverage. I dropped
temperatures area wide Wednesday for the crossing of the upper
wave but am having a hard time buying into such a potent
shortwave...especially given the recent track record of the GFS
offering up these closed low solutions in the 3-7 day time frame.
Thursday and Friday.... Models in agreement that after the wave
passes, a shortwave transient ridge will build ahead of yet
another upper low dropping into the eastern Pacific. But this is
where the models diverge significantly on possible solutions. The
EC is now advertising a powerful closed low dropping all the way
down to western WA by Saturday afternoon. The GFS is also
indicating a strong low will form over the eastern Pacific, but it
maintains that the low will stay much farther north; again a more
reasonable scenario given the recent long range miscues.
Either way, the extended forecast will continue with broad areas
of low pressure impacting the northwest U.S. through next weekend.
This will keep temperatures near normal for this time of year with
the occasional shot of showers/thunderstorms. /AB
12Z TAFS: Mid and high clouds will move into Central and NE
Washington today and then into SE Washington and North Idaho by
Saturday morning. Breezy NW winds will redevelop late afternoon
once again across the Cascade gaps and continue through the
evening hours. JW
.PRELIMINARY POINT TEMPS/POPS...
Spokane 86 62 83 59 82 55 / 0 0 10 0 10 0
Coeur d`Alene 86 59 81 57 81 53 / 0 0 10 10 10 0
Pullman 84 52 81 52 81 51 / 0 0 10 0 10 0
Lewiston 93 63 89 62 89 58 / 0 0 10 0 0 0
Colville 88 55 85 54 82 50 / 0 0 10 10 20 10
Sandpoint 84 54 78 52 78 51 / 0 0 20 10 10 10
Kellogg 84 54 78 54 77 51 / 0 0 30 10 10 0
Moses Lake 90 63 89 59 87 57 / 0 0 0 0 10 0
Wenatchee 89 66 88 64 83 58 / 0 10 0 0 10 0
Omak 88 62 89 59 84 54 / 0 10 0 0 10 0