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Area forecast discussion 
National Weather Service Spokane Washington
231 PM PDT Sat Jul 23 2016

Synopsis...
a warm and mostly dry Summer pattern will arrive this weekend and
persist through next week. However there will be minor shower
and thunderstorm chances near the Canadian border, from time to
time, through Thursday. High temperatures in the 90s will be
common for nearly all towns Thursday through at least Saturday.

&&

Discussion...
tonight through Tuesday...a zonal (westerly) flow will be over the
inland northwest through Tuesday. Moisture is limited in this flow through
Monday morning with dry air aloft supporting clearing skies this
evening after flat cumulus dissipates with the loss of daytime
heating. Flat cumulus will redevelop over the mountains Sunday
afternoon but with a warmer and drier air mass expect less
coverage of this compared to today. A weak wave then tracks into
the region Monday afternoon into Tuesday. This wave first reaches
the Cascades Monday afternoon. This combined with steep lapse
rates away from the crest may trigger scattered showers and
thunderstorms with the best chances from Lake Chelan north to the
Canadian border. Scattered showers and thunderstorms expand to
include the northern mountains on Tuesday. Surface based cape
values of 1000-1500 j/kg combined with a moist atmosphere with
precipitable waters increasing to near an inch will support
locally heavy rain and small hail with storms. Severe
thunderstorms are not expected with 0-6km shear values of only
10-15 kts.

A warming trend is expected through Monday as 850mb temperatures
warm to near 20c Sunday and 23c Monday. This will support high
temperatures rising into the upper 80s to mid 90s. Then a few
degrees of cooling on Tuesday as the weak wave tracks through. Jw

Wednesday through friday: the Pacific northwest has largely
escaped hot weather so far in July. Wenatchee has only had 3 days
at or above 90 degrees, and Spokane international has only hit 90
once. The European model (ecmwf) and GFS are in good agreement that we will add
several 90 degree days to our July stats next week. The hot high
pressure ridge responsible for the oppressively hot conditions
over the central U.S. Will retrograde into Southern California and
the Desert Southwest Wednesday and Thursday and remain through at
least Saturday. At this time, it looks like Friday and Saturday
will be the hottest days of the week with mid to upper 90s
throughout the region. Our typical hot spots in the l-c valley and
Columbia Basin will likely flirt with 100 Fri and Sat.

Saturday: if the medium range models verify, we can expect a cold
front next weekend. The latest GFS, ECMWF, and Canadian models
suggest that the front will arrive next Saturday or Saturday
night. At this time, it looks like a dry frontal passage. We will
be watching this closely. Breezy winds, hot temperatures, and low
humidity often raise wildfire concerns with this type of pattern
in late July. /Gkoch

&&

Aviation...
18z tafs: stratus over the valleys of NE Washington and north Idaho
which includes Sandpoint and Colville will continue to lift
through the morning...with an abundance of flat cumulus expected
across the region this afternoon. Cumulus will dissipate near
sunset this evening with the loss of daytime heating. VFR
conditions will continue at the taf sites through Sunday morning.
Jw

&&

Preliminary point temps/pops...
Spokane 55 86 60 91 63 89 / 0 0 0 0 10 10
Coeur D'Alene 52 86 55 91 59 89 / 0 0 0 0 10 10
Pullman 47 85 50 90 54 87 / 0 0 0 0 10 10
Lewiston 57 93 61 97 66 95 / 0 0 0 0 10 10
Colville 49 88 51 93 56 88 / 0 0 0 0 10 40
Sandpoint 47 82 49 87 52 86 / 0 0 0 0 10 20
Kellogg 49 83 52 87 54 86 / 0 0 0 0 10 10
Moses Lake 54 89 57 94 62 93 / 0 0 0 0 0 10
Wenatchee 60 89 64 93 67 90 / 0 0 0 0 10 10
Omak 57 90 60 94 65 92 / 0 0 0 10 20 10

&&

Otx watches/warnings/advisories...
Idaho...none.
Washington...none.
&&

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