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Area forecast discussion
National Weather Service Spokane Washington
337 PM PDT Tue may 23 2017

Synopsis...
a strong cold front will plow through the region this evening
bringing gusty winds especially to central Washington. Blustery
conditions will persist into Wednesday with afternoon temperatures
a solid twenty degrees cooler than today. Scattered showers and
thunderstorms will be possible on Thursday. Sunny and warmer
weather will return for the Memorial Day weekend with high
temperatures warming back into the 80s.

&&

Discussion...

..windy tonight with gusts of 45 miles per hour or more around Wenatchee...
Waterville...and Vantage...

Tonight into wednesday: Moses Lake hit 90 degrees for the first
time this season, and for the first time in months we are looking
at the passage of a dry cold front. The calendar says it is late
may, and it appears that mother nature is starting to deal US some
weather representative of the season. Late Spring is a time of
big temperature swings and gusty winds. Temps near 90 today, Moses
Lake will be closer to 70 tomorrow. Region-wide, we expect
temperatures to be 20 degrees cooler tomorrow afternoon than they
were today.

Our abrupt cool down will be accompanied by gusty west winds. The
tightest surface pressure gradient and sharpest cold advection
will occur during the mid to late evening hours. The strongest
gusts will likely occur around Wenatchee, Chelan, Waterville, and
Vantage. These areas often experience the strongest gusts during
evening wind events as they are prone to Cascade Gap winds. A Wind
Advisory will be issued for this evening and late tonight for the
aforementioned areas. Cooler and denser air spilling through the
Wenatchee valley, Kittitas Valley, and Down Lake Chelan often
increase the gust potential. Further east, places like Ritzville,
Pullman, Lewiston, Spokane and Coeur D'Alene will experience windy
conditions this evening and through the night. However, the night
time arrival of the higher momentum air aloft may not mix to the
surface efficiently. Look for gusts in the 30 to 35 mph range.
Breezy winds will persist into the day tomorrow (wed), but
pressure gradients will be weakening through the day.

Wednesday night and thursday: a cool upper trough will linger over
the inland northwest following tonight's cold front. The cool air
aloft will promote widely scattered showers Thursday. A few cells
Thursday afternoon may produce lightning, brief downpours, and
small hail. /Gkoch

Friday through Tuesday...an upper ridge off the coast near 130w on
Friday will move east over the region over the Memorial Day
weekend and remain in place through the middle of next week. With
the ridge axis to the west on Friday...some lingering convection
is possible over the Idaho Panhandle. Then significant warming and
drying Saturday through Tuesday as 850mb temperatures climb
towards 18-20c. Dry conditions are favored under the ridge
although with the warm temperatures GFS and European model (ecmwf) show increasing
surface based cape. There is expected to be a strong cap on
Saturday to limit convection. Sunday through Tuesday isolated
thunderstorms are possible in the mountains of northern Washington
and the Idaho Panhandle...but confidence in this is low with a
lack of forcing over the region...and the ridge axis overhead
possibly still providing a cap to get convection going. Main story
will be the warm temperatures with highs in the 80s...with the
warmest spots like Wenatchee, Moses Lake, Omak, and Lewiston near
90 for Memorial Day and Tuesday. Jw

&&

Aviation...
18z tafs: the passage of a dry cold front this evening will
produce a sharp increase in west winds for the inland northwest.
The timing and strength of the winds will be the biggest challenge
for the tafs. It is often difficult for strong and gusty winds to
persist all night long, but tonight's cold front is particularly
strong. The strongest gusts will likely occur at the Wenatchee and
Chelan airports (up to 35kts early this evening) with the
contribution of gap winds accelerating through the Wenatchee
valley and Down Lake Chelan. Further east, places like Spokane,
Coeur D'Alene, Pullman, and Lewiston will experience the tightest
pressure gradient and strongest 850mb winds between mid evening
and early morning which is the toughest time for efficient low
level mixing. /Gkoch



&&

Preliminary point temps/pops...
Spokane 49 62 46 67 47 71 / 0 10 10 20 20 10
Coeur D'Alene 49 62 44 66 44 70 / 0 10 10 30 30 20
Pullman 49 62 44 64 43 69 / 0 0 10 20 20 10
Lewiston 54 68 48 70 48 75 / 0 0 10 20 20 10
Colville 49 64 45 68 46 74 / 0 10 0 40 20 10
Sandpoint 48 62 40 64 41 69 / 0 20 10 30 30 20
Kellogg 45 59 41 63 41 68 / 10 10 10 20 30 20
Moses Lake 55 71 48 74 49 79 / 0 0 10 10 10 0
Wenatchee 55 68 49 74 51 79 / 0 0 10 20 10 0
Omak 51 70 49 74 49 79 / 0 0 10 20 10 0

&&

Otx watches/warnings/advisories...
Idaho...none.
Washington...Wind Advisory from 9 PM this evening to 3 am PDT Wednesday for

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