Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 260412
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
912 PM PDT MON MAY 25 2015

.SYNOPSIS...
A slow moving low pressure system will bring scattered afternoon
and evening thunderstorms to the Inland Northwest through
Wednesday. Locally heavy downpours, frequent lightning, and small
hail will be possible the next several days. Low pressure will
gradually depart by Thursday, bringing a decrease in precipitation
chances, but chances may increase again by early next week across
the region. Temperatures warm back above normal from Wednesday
into the end of the week, with highs pushing into 80s Thursday
onward.


&&

.DISCUSSION...
Late evening update: A closed low evident on satellite over
southern Stevens county as of 9 pm is shown by models to move east
northern Spokane and southern Pend Oreille counties overnight.
The best instability is located on the southwest side of this low
over the Upper Columbia Basin around Grand Coulee and Wilbur with
quite a bit of lightning activity this evening. Brief heavy rain
has been common with these storms with as much as 0.6 inches per
hour.  Overall the NAM has the best handle on the convection
currently and leaned towards the 00z NAM for the remainder of
tonight. As the low pulls east a bit overnight the area of mid
instability shifts into southern Lincoln, southern Spokane, and
northern Whitman counties. The NAM MU CAPE values of 500-1000 J/KG
in these areas during the overnight hours are probably
overdone...but given current convection on radar not showing any
signs of ending opted to increase pops and add a mention of
isolated thunderstorms in these areas overnight including the
Spokane area. Under the low itself...shower activity should only
be isolated over the Northeast Washington Mountains.
Meanwhile...with the low pulling away from the Cascades and low
level downslope flow in the Cascades...the chance of showers was
removed for the rest of tonight in this area.  JW

&&

.AVIATION...
00Z TAFS: There is good model agreement that a closed low over the
Cascades early this evening will move into the Spokane/Coeur
D`Alene area overnight and remained parked over this area through
Tuesday. This will result in a continuation of showers and
thunderstorms over the area...with the highest coverage during
peak heating (afternoon/evening). Although tonight there will
likely be more of a focus of the showers around and north of the
KGEG/KSFF/KCOE TAF sites with the closed low tracking into the
area. Brief heavy rain and small hail has been observed with these
storms.  JW

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        51  70  52  75  54  81 /  40  60  30  30  20  20
Coeur d`Alene  48  70  48  75  51  80 /  20  60  30  40  20  20
Pullman        45  68  48  71  49  78 /  40  40  30  40  20  20
Lewiston       53  74  55  76  56  84 /  20  50  40  40  20  10
Colville       49  73  49  80  51  84 /  20  70  40  30  20  20
Sandpoint      47  68  48  75  50  78 /  30  70  40  50  30  40
Kellogg        46  67  47  71  49  78 /  30  80  50  60  30  40
Moses Lake     52  79  52  82  55  88 /  20  40  20  20  10  10
Wenatchee      57  77  58  82  60  87 /  10  40  30  20  20  10
Omak           49  76  51  83  52  86 /  40  50  40  40  20  10

&&

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

$$



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