Area Forecast Discussion
Issued by NWS Spokane, WA
FXUS66 KOTX 140923
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
223 AM PDT Tue May 14 2013
The arrival of cooler, more seasonal temperatures will continue
through the work week and weekend which will allow many rivers to
recede. A couple of weak weather systems will bring scattered
showers and thunderstorms to the area for the mid-week period and
again for the weekend.
Today through Wednesday...A much cooler and drier air mass has been
ushered into the region behind last night`s cold front. After a
chilly start this morning, temperatures will be close to seasonal
normals with most valley locations in the mid 60s to low 70s.
Conditions will be much more stable today, with just a few showers
possible across the northern mountains where some residual shortwave
energy will scoot along the northern border.
The next approaching Pacific trough will push up a brief ridge over
the region overnight. Southerly flow ahead of the trough will bring
some warmer air into the Inland Northwest for milder overnight
temperatures tonight. This next system has a decent tap into a
moisture plume, although not nearly as impressive as the last one.
The surface cold front is also weaker than the previous system.
Showers should be more scattered in nature as the front progresses
through the forecast area Wednesday along with breezy winds.
The trough takes on a slightly negative tilt as it moves ashore.
This could increase the potential for thunderstorms across the
northeast zones but convective parameters are still looking
marginal. Will opt to keep thunder out of the forecast for now.
Cooler temperatures and drier weather will allow area streams and
rivers to recede over the next few days. /Kelch
Wednesday night through Sunday night...A more typical late spring
pattern will be over the Pacific Northwest through the weekend.
Westerly (Zonal) flow with a plethora of weak little short wave
disturbances will move through the region form west to east. The
zonal flow will tap into some Pacific moisture for a chance of
showers and possibly a thunderstorms or two over the mountains.
Temperatures will remain within a few degrees of seasonal normals
The models have been consistent showing a couple of stronger short
waves moving through the region...although there are still some
timing differences on just when these will move through. The NAM
seems to be the quickest with each feature and the GFS slowest
with the ECMWF in between but leaning towards a slower solution.
These stronger waves will result in better forcing and deeper mid
level instability that will support heavier showers and the chance
of a few late day thunderstorms...with the thunderstorms mainly
over the higher terrain. The first will move through the region
Wednesday afternoon with the associated trough moving trough
region and ejecting east Thursday evening. The cold core will remain
north in B.C but enough instability across the northern zones for
a little higher pops. The second will follow Friday evening...with
a secondary reinforcing wave following quickly Saturday night and
Sunday. This will result in the continuation of the showers and
mountain thunderstorms through Sunday. Winds will increase and
become gusty with each passing wave. /Tobin
Monday through Tuesday night...A potential lull from any weather of
significance should begin early next week, with perhaps a more
organized storm system dropping into the Inland Northwest by days
7 or 8. The lull may not be completely precipitation free,
however, as any small scale shortwave in general northwest flow
could trigger off a shower, or even an isolated thunderstorm.
Anything organized looks unlikely until a larger system scoots
down the BC coast line, eventually dragging a cold front through
the region. The temperatures will peak on Monday (slightly above
normal) before falling slightly on Tuesday. ty
Winds are expected to remain elevated through 08z and then decrease
overnight. KSFF, KCOE, KPUW could see some shallow fog form towards
daybreak as winds continue to decrease. Mainly mid and high level
clouds expected Tue with lighter winds.
.PRELIMINARY POINT TEMPS/POPS...
Spokane 64 43 66 45 66 46 / 0 0 10 10 30 30
Coeur d`Alene 63 40 65 43 65 43 / 0 0 20 20 40 30
Pullman 63 40 67 43 66 42 / 0 0 10 10 30 20
Lewiston 71 45 74 50 73 50 / 0 0 10 10 20 20
Colville 68 40 70 43 71 42 / 10 10 30 20 40 30
Sandpoint 63 39 65 42 65 40 / 10 0 20 20 40 30
Kellogg 61 41 63 46 62 45 / 10 0 20 20 40 30
Moses Lake 72 45 73 47 76 48 / 0 0 10 10 20 10
Wenatchee 70 48 69 49 72 49 / 0 0 20 10 20 20
Omak 70 41 70 42 72 43 / 0 10 20 30 30 20