Weather Service Report


581 
FXUS66 KOTX 282119
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
219 PM PDT Sun May 28 2017

.SYNOPSIS...
High pressure continues over the Inland Northwest through Tuesday
with unseasonably warm temperatures. There is a small chance of 
thunderstorms in the higher elevations, otherwise expect dry
weather. This warm spell will contribute to rises on rivers from 
the Cascades into north Idaho. A cold front arrives Tuesday night
with a better chance of showers and thunderstorms. This will be 
followed by cooler and unsettled weather for Wednesday into the 
rest of the week. 

&&

.DISCUSSION...
Tonight through Wednesday: Warm and dry weather will transition 
to cooler and unsettled by mid week. The ridge of high pressure 
will remain over the region, allowing temperatures to warm through 
Tuesday, which is to be the warmest day of the week and the year 
thus far. Instability will increase over the mountains with weak 
orographic lift to weaken cap and enough moisture. Currently the 
convection is confined to extreme northeast Washington into north 
Idaho with isolated showers and embedded thunderstorms. Weak 
convection is possible along the Cascade crest. The activity is 
expected to decrease early this evening followed by clearing 
skies. Should see a repeat performance for Monday with slightly 
warmer temperatures and another round of mountain convection. 
Possibly a title more activity in the Cascades as a band of mid 
level moisture is projected to increase over the Cascades. By 
Tuesday, the upper ridge axis pushes across eastern Washington and
a moister southerly flow aloft will spread from the Cascades into
the central Basin. Instability will increase by afternoon with 
the main target over the Cascade given the weaker cap, more 
moisture. Temperatures should peak by Tuesday afternoon. Then 
Tuesday night into Wednesday morning, a cold front will push 
through the region aided by a shortwave trough aloft. A chance of 
showers will accompany the front across the region Tuesday night. 
Could see some thunderstorms, but better chances will be early in 
the evening across north central Washington. Thunder chances 
decrease overnight, but still there looks to be enough dynamics 
and mid level lapse rates to keep a mention along the Canadian 
border. Winds will shift from east to southwest to west with the 
frontal passage and then breezy winds by Wednesday. Temperatures 
will cool significantly by Wednesday afternoon, some 10 to 15 
degrees. By Wednesday afternoon, the best chance of convection 
will lie in northeast Washington and the Idaho Panhandle.

HYDROLOGY update: The unseasonably warm spell will lead to 
additional mountain snow melt, increased run off and higher rises 
on area rivers and streams. The main area of concern will be in 
north central Washington with the Cascade basins to the Okanogan 
Basin with a couple rivers nearing flood stage early this week. 
Anticipate higher flows for much of the week. Check the latest 
flood products for updates. /rfox. 

Wednesday night through Sunday...The Inland NW transitions to a
more seasonable weather pattern as a cooler...progressive...westerly
flow develops. At this point the majority of model solutions show
no strong waves entering which should keep most lower elevations
on the drier side. Exception is the latest 12z ECMWF model which
shows a more substantial trough for next weekend which would
result in a broader area of showers. At minimum...weak waves in
this zonal flow combined with afternoon heating will lead to a
chance of showers each day in the mountains with a slight chance
of thunderstorms.  JW

&&

.AVIATION...
18Z TAFS: High pressure will continue VFR conditions at the TAF 
sites through the period. Some cumulus is possible after 19z and 
dissipate by 02z. Isolated showers are possible in the nrn 
mountains, but should not affect the TAF sites. /rfox. 

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        58  86  60  87  58  75 /   0   0   0   0  40  30 
Coeur d'Alene  52  84  54  86  55  74 /   0   0   0   0  30  20 
Pullman        53  83  53  85  55  73 /   0   0   0   0  20  30 
Lewiston       56  90  59  90  61  80 /   0   0   0  10  20  30 
Colville       55  87  57  88  58  76 /   0   0   0   0  40  30 
Sandpoint      50  83  52  83  54  75 /  10  10   0   0  10  30 
Kellogg        51  84  54  84  53  76 /  10  10  10   0  10  20 
Moses Lake     53  92  56  92  60  83 /   0   0   0   0  20  20 
Wenatchee      61  90  64  89  58  80 /   0   0  10  10  30  10 
Omak           54  89  56  89  60  81 /   0   0   0  10  50  30 

&&

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

$$

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Western Regional Climate Center, wrcc@dri.edu