Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Spokane Washington
455 PM PDT Friday Oct 9 2015

Saturday will be quite warm with very windy conditions developing
in the late afternoon. A fast moving cold front will bring a good
chance of rain to the region Saturday night. It will also be
windy Saturday night with the front. Mild and mainly dry weather
is expected to return for the early to middle part of next week.


early evening update: weak front passing through NE Washington
into the Idaho Panhandle will continue to generate light showers
or sprinkles into this evening. Radar has picked up on this with
web cams and surface observations showing isolated rain
showers reaching the ground...and thus this has been added to the
forecast. Rest of forecast discussion below remains valid.


00z tafs: mid and high clouds will continue to stream into the
region through Saturday ahead of an approaching weather system.
Taf sites should remain dry through Saturday morning except for a
few brief sprinkles possible at kgeg/ksff/kcoe this evening. The
NAM model shows the boundary layer becoming saturated Saturday
morning over northern Washington and near the Cascades. There
will be a brief chance for stratus 12-18z Sat at kgeg/ksff/kcoe/kmwh/keat
but most likely VFR conditions will continue. The next system will
spread rain into the Cascades Saturday afternoon, with a chance of
rain reaching keat near 22z.


Previous discussion...

Tonight...moisture continues to stream up the west side of the
weak ridge of high pressure with ridge axis placement near north
Idaho this afternoon. The ridge axis will displace to the east
tonight and allow for the moisture streaming through the west side
of the ridge to move closer...thus the cloud cover remains mostly
cloudy for tonight. The flow still is too southwesterly in
orientation to overcome the rain-shadow in the Lee of the Cascades
so pops and qpf for rainfall do not extend very far east of the
Cascade crest tonight. As is expected to be the case with abundant
cloud cover and ridging the forecast temperatures for tonight
remain on the warm side of climo. As more drying of the lower
boundary layer took place today fog is less likely to form to the
degree that it did last night and with the increased southwest
winds keeping it mixed no mention of fog has been included in the
forecast for tonight. /Pelatti

Saturday and sunday: with a quick-moving short-wave crossing the
area late Saturday, much of ern WA and north Idaho will be under the
threat of showers... most of which will fall near the Cascade
crest and north Idaho mountains. Rain amnts of 1 to 2 inches will be
possible near the Cascade crest with one-half likely in the Idaho

For winds: a wind advsy was issued for late Saturday afternoon
and into Sunday morning associated with the aforementioned short-
wave trough. Timing is not ideal for strong winds, with the fropa
not occurring until Sat evening. However...pressure gradients
(ahead of and behind the front), a nearly unidirectional SW/west
vertical wind profile with 850 mph winds of 45 kts, and steep
midlevel lapse will aid in mixing these stronger winds aloft to
the surface. And with the upper low moving over the area Saturday
nt, showers (and possibly isolated thunder) will also help to
Transfer winds to the sfc and break or weaken any sfc-based
inversion Sat nt that would inhibit gusts valley winds. These
showers are not expected to be widespread however. Local studies
support gusts of 50 to 60 mph on exposed mountain ridges. Hunters
need to take precautions and watch for falling limbs.Bz

Monday through friday: outside of a weak cold front passing
through on Monday, this period is expected to be warm and dry. The
cold front is expected to have minimal impact to the region,
bringing a slight chance of showers to the Cascade crest with a
small amount of precip. A Flat Ridge pattern is going to dominate
the region for the remainder of the period. The models are in
good agreement and are continuing to strengthen the ridge and
decrease the amount of moisture. This will keep the region precip
free. Temperatures are the main impact for the region. The highs
are expected to be near 5 to 10 degrees above the season normals
for this time of year. High temperatures are expected to be in the
upper 60s to low 70s. Lows are expected to be in the range of mid
30s to low 40s. /Jdc


Preliminary point temps/pops...
Spokane 53 74 48 64 44 68 / 10 20 60 10 10 10
Coeur D'Alene 53 74 47 64 41 68 / 10 10 60 10 10 10
Pullman 52 76 48 65 42 72 / 10 10 30 10 10 10
Lewiston 54 81 53 72 48 76 / 0 0 30 10 10 0
Colville 50 71 44 64 40 64 / 10 20 70 10 10 10
Sandpoint 51 71 47 65 36 65 / 20 20 70 10 10 10
Kellogg 49 71 46 60 41 67 / 20 10 70 30 10 10
Moses Lake 53 74 47 70 42 73 / 0 10 20 0 10 10
Wenatchee 53 73 48 70 50 72 / 10 20 20 0 10 10
Omak 49 71 43 67 45 67 / 20 40 40 0 10 10


Otx watches/warnings/advisories...
Idaho...Wind Advisory from 2 PM Saturday to 1 am PDT Sunday for Coeur
D'Alene area-Idaho Palouse.

Wind Advisory from 2 PM Saturday to 5 am PDT Sunday for central
Panhandle mountains-northern Panhandle.

Washington...Wind Advisory from 2 PM Saturday to 1 am PDT Sunday for lower
Garfield and Asotin counties-northeast mountains-Spokane
area-Washington Palouse.

Wind Advisory from 2 PM Saturday to 5 am PDT Sunday for
northeast Blue Mountains.

Wind Advisory from 2 PM to 11 PM PDT Saturday for Moses Lake
area-upper Columbia Basin-Waterville Plateau.



National Weather Service Glossary of Abbreviations