Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 260114
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
614 PM PDT Tue Apr 25 2017

.SYNOPSIS...
Expect cool, breezy, and showery weather this week. The most
widespread precipitation will occur tonight into Wednesday with
the potential for a half inch or more of rain over portions of the
Idaho Panhandle and southeast Washington. Mountain passes could
see a few inches of snow overnight into the morning hours. A ridge
of high pressure moves in Saturday delivering a brief dry period
before more unsettled weather moves in Sunday and into early next
week.


&&

.DISCUSSION...
Evening update: The forecast has been updated through Wednesday
with the biggest change to lower POP`s and precipitation amounts
on Wednesday across the Columbia Basin and Spokane area. Models
have trended much drier compared to solutions yesterday with a
a further southward placement of the moisture feed...now focused
over Oregon. Water vapor satellite supports this with a wedge of
drier air over Vancouver Island that will be tracking east-
southeast over the region.

For this evening showers continue mainly north of Spokane and the
Idaho Panhandle. These will be moving northeast and gradually
decreasing after sunset.  Meanwhile the next system is sending a
disorganized area of light rain from western Washington towards
The Dalles, OR. This area of precipitation will move moving east
tonight. With 20-30F temperature-dewpoint spreads as of 6 pm its
expected this weak band of precipitation will only bring sprinkles
or spotty light rain to Central Washington away from the crest as
much of the rain evaporates before reaching the ground. Over
Eastern Washington and north Idaho more efficient isentropic
ascent should bring rain to most locations overnight.

Behind this area of rain drier westerly flow takes over across
the Columbia Basin on Wednesday with the bulk of the showers
focused along the Cascade crest...northern mountains...Idaho
Panhandle and SE Washington. Despite the drier air cold
temperatures aloft and steepening lapse rates will help promote
showers in these areas. A well mixed atmosphere and 850mb winds of
20-30 kts across the Columbia Basin...Spokane area...and palouse
will lead to breezy winds however.  JW

&&

.AVIATION...
00Z TAFS: Overall models have trended drier into Wednesday.
Showers will stay mainly north of the TAF sites this evening over
the mountains. A weak frontal band passes through overnight
bringing a chance of mainly sprinkles to KEAT/KMWH with a
continuation of VFR conditions into Wednesday as drier air aloft
moves overhead. For the Eastern TAF sites steady light rain is
expected overnight with CIGS lowering to MVFR. After the band of
rain passes a moist boundary layer and low level upslope will lead
to stratus Wednesday morning...which will lift by early afternoon
as drier boundary layer from Central Washington advect into the
Spokane area TAF sites. For KPUW/KLWS rain showers will be more
favored to continue into the afternoon and may keep MVFR
conditions persisting beyond the morning hours especially KPUW. A
well mixed atmosphere and 850mb winds increasing to 20-30 kts will
lead to breezy west-southwest late Wednesday morning and
afternoon. JW

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        42  52  36  52  36  54 /  80  60  50  40  20  40
Coeur d`Alene  40  51  35  50  35  53 /  80  90  80  90  30  40
Pullman        42  50  37  50  36  51 /  90  90  60  50  20  40
Lewiston       46  54  41  56  39  56 /  90  80  40  30  20  30
Colville       40  53  37  53  37  56 /  60  90  50  40  20  30
Sandpoint      38  49  36  48  36  51 /  90 100  80  90  60  40
Kellogg        37  45  35  44  34  47 /  90 100  90  90  60  40
Moses Lake     45  61  40  60  38  61 /  40  20  10  10  10  10
Wenatchee      44  58  39  57  39  59 /  20  10  10  10   0  10
Omak           43  59  38  57  38  60 /  30  50  10  10  10  10

&&

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

$$



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