Area Forecast Discussion
Issued by NWS Spokane, WA

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661
FXUS66 KOTX 090011
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
411 PM PST MON FEB 8 2016

.SYNOPSIS...
Strong high pressure will persist into Wednesday. Dry and mild
conditions are expected for the first half of the week. A more
progressive and unsettled pattern will return late this week
bringing a chance of light rain Thursday in the Cascades and over
the rest of the region Friday through the weekend.

&&

.DISCUSSION...
Tonight and Tuesday: Strong high pressure will continue to build
in over the region. The ridge axis will shift further more into
the interior over the next 24 hours. This will shunt higher cirrus
clouds spilling over the ridge further north of the region with
clear skies becoming more prevalent overnight. The tricky part of
the forecast will be where will the fog form and how long will it
linger into Tuesday. The thought process is that since winds will
be weak from the east that the best potential for fog in the basin
will be across the wester portions (i.e. generally west of
Ritzville). The northern valleys over to the east slopes of the
northern Cascades are also expected to see fog form overnight.
Warm temperatures this afternoon (into the low to mid 50s) and
light downsloping winds across the southeast portion of the region
should keep these areas fog free. How much of these clouds
dissipate from the south will play a big role as far as how much
the northern and western fringe of the basin warms up tomorrow.
The forecast reflects the idea that much of the low clouds will
erode across the basin with highs warming up into the upper 40s
and low 50s. Temperatures are expected to be warmest across the
Palouse, into the Central Panhandle Mtns, Lewiston-Clarkston Vly
and on the Camas Prairie where record high temperatures in the mid
to upper 50s will be possible. /SVH

Tuesday night through Monday...Ridge of high pressure continues to
influence the region in some shape or form until a vigorous wet
cold front passage occurs Saturday. The remaining weak dirty
ridging left in place is such that the flow remains active as
moisture and disturbances run through the top of it and through
Eastern Washington and Northern Idaho. What this means is stagnant
weather conditions will continue with low level easterly flow
banking various intensities of low clouds and fog into the
lowlands and valleys with the exceptions of the Spokane area,
Palouse, and just about all of North Idaho as the easterly winds
work to keep those exception areas from being stagnant.
Backtracking a bit the upper level ridge axis is over North Idaho
for most of this time interval between Tuesday night and Friday
night and some gradual de-amplification of the ridge occurs as
early as Wednesday night and this may allow for very light
precipitation to fall, mostly in the form of very brief and
infrequent light rain or sprinkles as the warm inversion remains
in place. Mid slope elevations will be quite warm as the
subsidence inversion from this ridge influences those elevations
while at the very bottom of the inversion some locations will not
mix well, if at all, and stay cold and cloudy. /Pelatti

&&

.AVIATION...
00Z TAFS: A strong ridge of high pressure will remain over the
forecast area through the week with much drier air moving into the
region. For tonight through Tuesday clearing skies and light
northeast to southeast winds will allow good radiational cooling
and the development of strong morning inversions. This in turn
typically will result in the formation of fog and stratus. The
drier air and easterly gradient will keep that in check somewhat.
For KGEG/KSFF fog and stratus will likely form late tonight and
linger through the morning. So VFR/MVFR conditions will drop to
IFR/LIFR cigs/vsby 14z-20z before clearing in the afternoon.
Confidence is only low to moderate for LIFR conditions. KCOE-
KPUW-KLWS will remain VFR...however some ground fog may form early
in the morning near KCOE. The easterly gradient will allow the
moisture to pile up along the east slopes of the Cascades. The
best chance for IFR/LIFR vsby/cigs will be at KMWH- KEAT between
08-18z but again confidence is only moderate with the amount of
dry air in place. Tobin

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        30  49  31  46  35  48 /   0   0   0   0  10  10
Coeur d`Alene  31  51  31  48  32  49 /   0   0   0   0  10  10
Pullman        36  55  35  54  38  54 /   0   0   0   0  10  10
Lewiston       37  57  38  57  39  58 /   0   0   0   0  10  10
Colville       28  43  31  43  33  44 /   0   0   0   0  10  20
Sandpoint      28  47  31  44  31  44 /   0   0   0  10  10  10
Kellogg        30  51  31  48  33  50 /   0   0   0   0  10  10
Moses Lake     29  49  31  47  36  49 /   0   0   0   0  10  10
Wenatchee      30  43  32  44  36  45 /   0   0   0   0  10  10
Omak           27  41  30  40  34  40 /   0   0   0   0  10  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until 10 AM PST Saturday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$



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