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Area forecast discussion 
National Weather Service Spokane Washington
422 am PDT Friday Aug 1 2014

Synopsis...
very warm conditions will continue with isolated to scattered
showers and thunderstorms expected through Sunday. No significant
relief from the hot weather is forecast through the seven-day
forecast period. However, only a few spots will reach the
100-degree mark. The showers and thunderstorms the next several
days are not expected to be strong or severe but could result in
localized heavy downpours and gusty outflow winds.



&&

Discussion...
today through Saturday...monsoonal moisture is starting to spread
north into the forecast area this morning. Satellite water vapor
imagery shows the deepest moisture moving north just on the west
side of the central Cascades. Regional radar is showing showers
and thunderstorms tracking north through western Oregon and also
isolated light returns across the NE blues and Camas Prairie.
These areas will be ripe for scattered thunderstorms this
afternoon as surface based instability increases. Model soundings
show inverted v shape with dry sub cloud layer. The last several
days have been hot and dry so it will take some time for
thunderstorms to transition from high based "dry" storms to a
wetter variety. We coordinated with Storm Prediction Center and agreed on an area of
critical fire weather for scattered dry thunderstorms which
includes the Cascades and the higher terrain of Washington surrounding the
Columbia Basin. A Fire Weather Watch continues for the east slopes
Cascade zones east to the Okanogan Valley and Waterville Plateau.
I will leave it as is until the day shift can coordinate with
imets on active fires to determine if it needs to be extended in
area. Thunderstorm coverage will diminish overnight as surface
based instability lessens. We will see an increase in convection
Saturday but storms should transition to wet variety by then as
pwats increase to around an inch. Temperatures will remain well
above normal today. There should be some cooling Saturday but that
will depend on where showers occur and how much precip falls.
/Kelch

Saturday night through Thursday...no real big changes to the
model guidance over the past 24 hours. A slow moving trough will
eject off the mothership low in the Gulf of Alaska and track
through the inland northwest Saturday night into Sunday. The mid
level front is not overly impressive. However there will be plenty
of moisture to work with. Both sb cape and mid level cape will
support showers and thunderstorms Saturday night through Sunday.
Pwats are well above normal so localized heavy rain is probable
along with small hail. With the trough passage and cloud cover
expect several degrees of cooling.

Sunday night through Thursday the flow will flatten and become
mainly zonal. A few weak waves will move through the flow pumping
up a weak ridge at times followed by a fast moving and weak
disturbance. By this time we will lose the moisture tap and the
result will be Manly some cloud build ups on the ridges and maybe
a sprinkle or two over the northern mountains. Temperatures will
rebound right back to 5-10 degrees above normal with no relief in
sight from the hot weather. Of bigger concern will be that each
of the weak waves will increase the winds through the Cascade gaps
at times. These are typically late afternoon and overnight events
aided by drainage winds off the terrain, with winds becoming
breezy in the evenings and overnight. Relative humidity is
expected to remain very dry with poor relative humidity recoveries
at night on mid slopes and ridges. /Tobin

&&

Aviation...
12z tafs: VFR conditions expected the next 24 hours. Mid level cloud
deck is spreading in from the south and thickening. There is a
slight chance of showers and thunderstorms after 21z for klws,
kpuw and keat. If any thunderstorms do develop near
airports...strong gusty outflow winds will be possible. Convective
showers and thunderstorms will diminish after 02z Saturday. /Ek



&&

Preliminary point temps/pops...
Spokane 96 68 94 66 94 66 / 10 10 20 20 10 10
Coeur D'Alene 95 63 92 63 93 61 / 10 20 30 30 10 20
Pullman 95 58 93 59 93 57 / 20 20 20 20 10 10
Lewiston 101 70 98 71 100 69 / 30 30 20 20 10 10
Colville 98 59 96 58 95 60 / 10 20 30 30 20 10
Sandpoint 93 56 89 56 89 54 / 10 20 30 30 20 20
Kellogg 91 63 89 62 89 60 / 20 20 30 30 20 20
Moses Lake 100 65 98 65 99 65 / 20 20 20 20 10 10
Wenatchee 98 72 97 71 98 73 / 20 20 20 20 10 10
Omak 102 69 97 67 98 68 / 30 30 30 20 10 10

&&

Otx watches/warnings/advisories...
Idaho...none.
Washington...Fire Weather Watch through this evening for East Washington
south central Cascade mountains (zone 680)-East Washington
south central Cascade valleys (zone 676).

Fire Weather Watch from 11 am PDT this morning through this
evening for East Washington central Cascade mountains (zone
682)-East Washington central Cascade valleys (zone 677)-
East Washington north Cascades (zone 685)-East Washington
northern Columbia Basin (zone 673)-East Washington
Okanogan/Methow valleys (zone 684).

Flash Flood Watch from 11 am PDT this morning through this
evening for east slopes northern Cascades-Okanogan Valley-
Wenatchee area.

&&

$$

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