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000
FXUS66 KOTX 190018
AFDOTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
518 PM PDT Sat May 18 2013

.SYNOPSIS...
Scattered showers and isolated thunderstorms will develop again
this afternoon and evening. The greatest threat of thunder will
occur over the northeast corner of Washington and much of the
Idaho Panhandle. Precipitation chances will diminish a bit on
Sunday and by Monday most locations will be dry. This drying will
come to an abrupt end by Tuesday afternoon and into Wednesday as a
a very cool and wet upper level low parks itself over the Inland
Northwest. Steady, moderate precipitation will be possible
especially over northeast Washington and the northern Panhandle.


&&

.DISCUSSION...
Late afternoon update to the forecast for this evening. Added some
isolated thunderstorms across mainly Okanogan County to Ferry
County. LAPS data shows CAPE values up to around 400 J/kg and we
have already seen a handful of lightning strikes this afternoon
across this area. The thunderstorm threat will mainly only go
through until sunset. Once we lose our surface heating across
these areas, we shouldn`t retain enough instability for
thunderstorms to continue. Also added some isolated showers across the
basin as the next wave crosses the Cascades. Radar imagery does show
some weak echoes developing across the Moses Lake Area into the
Upper Columbia Basin. These showers are not expected to produce
much in the way of rainfall, but we could see around a hundredth
or so through this evening underneath these showers. The HRRR
model has the possibility for these showers reaching the Spokane
Area around 8:00 PM; however, the best forcing with this wave across
the basin will remain more over our southern zones, so not
expecting much from these showers once they get this far east into
the Spokane Area. /SVH


&&

.AVIATION...
00z TAFS: An upper level trough and weak disturbances embedded
within will aid in generating showers especially over the
mountains. Isolated thunderstorms will also be possible mainly
over the mountains north of the Columbia Basin though 03z this
evening. Westerly flow in the mid levels will lead to downslope
flow off the Cascades with dry conditions persisting at KEAT/KMWH.
TAF sites that receive showers could see low stratus forming after
15Z but confidence is low that conditions will fall below VFR for
any TAF site. /EK




&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        45  66  46  72  52  75 /  10  20  10   0   0  20
Coeur d`Alene  45  65  44  71  47  75 /  10  30  20   0   0  30
Pullman        43  63  42  71  47  76 /  10  20  10   0   0  20
Lewiston       49  68  49  77  53  83 /  10  20  10   0   0  20
Colville       45  72  43  78  45  79 /  30  20  20  10  10  40
Sandpoint      43  65  42  71  44  75 /  10  50  30  10  10  30
Kellogg        44  60  46  69  50  74 /  10  40  30  10  10  20
Moses Lake     47  76  46  80  50  79 /  10  10   0   0   0  20
Wenatchee      49  73  49  78  53  74 /  10   0   0   0   0  20
Omak           45  74  43  77  46  76 /  50  10  10   0   0  30

&&

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

$$