FXUS66 KOTX 080531
AFDOTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
931 PM PST Tue Feb 7 2012

.SYNOPSIS...A weak weather system will bring a shot of rain and
snow to the area on Wednesday otherwise high pressure will
persist over the Inland Northwest through Friday. A more active
weather pattern is expected over the weekend with mainly mountain
snow showers...but no major storms are expected.

.DISCUSSION...

Update for tonight High clouds are ever-so-slowly streaming into
the region in advance of a weak mid-level system that is shearing
out to the northeast starting from coastal Oregon. This system is
forecast to continue slowly northeastward overnight spreading
very weak isentropic ascent in the 290-300K layer across the
Cascades. Low level upslope flow at 850 mb may assist the
isentropic ascent in generating upward motion however the lifted
layer is very dry at the moment and the boundary layer is drier
still. As a result it will take a long time to generate much in
the way of precipitation at the ground. This is evidenced by a
lack of rain reports where radar is currently showing
precipitation across large portions of the Oregon Cascades
western Oregon and southwest Washington. This is even with
surface dewpoint depressions of roughly half of what are currently
being observed to the east of the Cascades. As a result even with
low level upslope help overnight it seems hard to believe much
more than flurries will be possible over the extreme southwestern
portion of the CWA before morning this generally being a line
from Stehekin to Moses Lake and southwestward.

In other news strong dewpoint depressions coupled with strong
radiational cooling in advance of the high cloud shield this
evening have allowed surface wet bulb temperatures to fall below
freezing across the entire CWA. Model soundings indicate only an
insignificant warm layer aloft that fails to reach the 0C isotherm
on the newest 00z NAM guidance. As a result any precipitation
that falls over the southwestern CWA overnight should be
exclusively light snow or flurries with little worry about any
other precipitation types at this time. /Fries

.AVIATION...
06Z TAFS Benign weather this evening through most of the night will 
slowly give way to a weak warm front crossing the region tomorrow. 
Expect cigs to gradually lower overnight. Near mvfr cigs will likely 
occur as the warm front crosses the region tomorrow morning for KMWH 
and KEAT and tomorrow afternoon for KPUW and the KGEG-KCOE 
corridor. Some flurries will also be possible around the time of the 
lower cigs as well...possibly mixed at times with -ra around KPUW 
and in the lower elevations of SE WA. Precipitation should end by 
Wed evening in most locations. /Fries

.PRELIMINARY POINT TEMPS/POPS...
Spokane        24  42  26  43  30  43 /   0  10  10  10  20  20 
Coeur dAlene  23  42  27  42  29  43 /   0  20  10  10  20  20 
Pullman        28  42  30  45  32  46 /   0  30  20  10  10  20 
Lewiston       30  48  32  49  34  50 /   0  20  10  10  10  10 
Colville       20  42  23  42  26  43 /   0  10  10  10  20  20 
Sandpoint      22  39  25  40  26  40 /   0  10  10  10  20  20 
Kellogg        22  40  26  41  27  41 /   0  20  30  10  20  20 
Moses Lake     25  44  25  46  28  46 /  10  20  10  10  10  10 
Wenatchee      25  41  27  44  29  44 /  10  20  10  10  10  20 
Omak           18  36  21  41  25  41 /   0  10  10  10  10  10 

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.