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Area forecast discussion 
National Weather Service Spokane Washington
500 PM PDT Thursday Mar 26 2015

Synopsis...
Friday through the weekend will be much warmer than average with
afternoon temperatures in the 60s and even some lower 70s down in
the Columbia Basin. Record high temperatures are possible Friday
afternoon. Precipitation chances will be tied to two cold front
passages. The first arrives Friday night and a second Monday night
or Tuesday. Gusty winds will accompany each front...especially
Tuesday.

&&

Discussion...
tonight and Fri: pcpn and thunder chances, as well as the potential
for record high temps Fri are the primary areas of focus. Quickly
amplifying upper ridge over the pac NW overnight will help to
produce clearing skies, the result of which will be another chance
of valley fog for the nrn valleys of WA and the ID Panhandle.
This is contingent upon the current mid and high cloud ceilings
over these same areas (which has been very slow to clear out),
actually does clear out later tonight. As a cold front approaches
the coast tonight, a plume of convective instability (mainly in
the 700-500mb lyr) moves NE across southeast WA between 12z and 18z on
the majority of model guidance, with both the GFS and sref showing
a bullseye of mid cloud ceilings tracking NE. Though no model
guidance generates pcpn, this is a typical nocturnal convective
pcpn pattern. We kept it dry... but we'll keep an eye on it. For
Fri...no big changes to the fcst as the low- level thermal ridge
surges north into ern WA ahead of the cold front. Thermodynamic
profiles still support record or near-record high temps for a
number of towns.

..see our latest wx story on our home Page to see which towns may
be breaking records...

By Fri afternoon, the sfc may remain capped as far as thunder
chances go for southeast WA until late afternoon. It's likely we'll see
the first showers develop over NE Oregon then develop/advect NE
into southeast WA and the cntrl ID Panhandle thereafter. Confidence is
not great as far as the timing and areal extent, with only about
half of the models wanting to generate convective pcpn coinciding with
the main axis of sfc-based instability.Bz

Friday night through Thursday...the longwave pattern remains
dynamic. It starts out with ridge with axis placement to the east
of the Pacific northwest which allows for approach of weather
systems from the southwest and west starting Friday night. Models
have been consistent in not only depicting such a system to move
through Friday night through Saturday they also hint at convection
firing up ahead of it, possibly in the form of thunderstorms over
southeast Washington near the Blue Mountains and southern portions
of the northern Idaho Panhandle. A moisture rich baroclinic band
juxtaposed and positively slanted between an area of low pressure
over the Gulf of Alaska and weak ridging over the inland northwest
remains in place afterward for Saturday night into Monday. This
fairly persistent positioning of the baroclinic band allow for low
pops for light rain lingering along a thin area in the Lee of the
north Cascades and across the southern British Columbia border
without much extension southward. This would leave locations
further to the south with dry conditions and above normal
temperatures. Monday night a cold front runs over and flattens the
ridge allowing colder, wet, windy and unsettled weather to return.
What remains in the wake of this Monday night/Tuesday cold front
passage is a general weak trof and/or flat progressive zonal flow
Tuesday night through Thursday. Such a general trof would favor
continued cool temperatures and off an on mainly diurnally driven
showers. /Pelatti

&&

Aviation...
00z tafs: high pressure will continue to build in over the region
tonight. This will result in a decreasing trend in low to mid
level cloud cover, but some high level cirrus is expected to hang
around. There is the potential for fog to redevelop late tonight
into the early morning hours across the northern mountain
valleys. This fog may also develop far enough south to affect the
ksff and kcoe taf sites, but confidence is low. /Svh

&&

Preliminary point temps/pops...
Spokane 42 70 46 60 38 59 / 0 0 60 30 0 0
Coeur D'Alene 40 69 43 60 36 59 / 0 0 60 60 0 0
Pullman 44 71 45 57 39 58 / 0 10 70 50 0 0
Lewiston 45 75 49 63 40 63 / 0 10 70 50 0 0
Colville 40 73 43 62 37 61 / 0 10 60 30 0 10
Sandpoint 37 68 42 59 34 58 / 0 10 60 60 0 0
Kellogg 40 67 43 56 36 57 / 0 10 80 90 10 0
Moses Lake 42 73 46 64 38 65 / 0 0 20 10 0 0
Wenatchee 47 72 47 62 42 66 / 0 0 20 10 0 10
Omak 42 71 42 64 36 64 / 0 10 40 10 0 10

&&

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

$$

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