112
FXUS66 KOTX 070604
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1004 PM PST Wed Nov 6 2024

.SYNOPSIS...
Drier and quieter weather is forecast through Friday night as
high pressure moves over the area. Expected colder nights with
most areas dropping down into the 20s with afternoon highs
rebounding mainly into the 40s. More unsettled weather is
forecasted beginning late Friday with a return of valley rain and
mountain snow.


&&

SHORT TERM...Today through Friday...

Bottom Line Up Front


1. Upper level ridge will bring chances of fog/freezing fog to river
   valleys

2. Seasonal daytime temperatures with cold overnight lows


Current satellite shows clear skies over much of the region with
some lingering high clouds over the Okanogan Valley. Clear skies
will continue through the forecast period as an upper level ridge
will gradually move in. North flow aloft will continue to bring in
cool and dry air ahead of the upper level ridge which will allow for
fog/freezing fog in many of the fog prone river valleys much like we
saw this morning. Models and near 85% of the raw ensembles show the
dew points reaching within range of the overnight temperatures and
coupled with the lingering mid level moisture, fog is likely to set
up along the river valleys. Highest confidence is the Pend Oreille
river basin, Spokane Valley, highway 395 between Spokane and Kettle
Falls, Carlton through Winthrop and lastly around Leavenworth.

Other than the influx of fog under the ridge, temperatures will
hover around to slightly above seasonal average according to the
EFI. 40% of the raw ensembles show temperatures to be in the upper
40s to low 50s through the short short term through the Basin and
valleys. However, EFI does signal that overnight temperatures will
be at or slightly below normal with 50% of the ensembles showing
temperatures in the mid to upper 20s with temperatures in the teens
through many of the river valleys. Bennese/90

.LONG TERM...Saturday through Wednesday...Models and ensemble
clusters are in good agreement on the evolution of the longwave
pattern through the extended period. Essentially there will be two
trough passages through the extended one Saturday night and Sunday
and another Monday into Tuesday. POPS with the first system will
range from 50-90% except 30-40% Columbia Basin. QPF amounts will
generally be around .10 inches except .25 to locally .50 inches
along the Cascades and Idaho Panhandle, where 24 hour probabilities
of exceeding .25 inches of QPF ending at 4 pm Sunday are around 75%.
Snow levels will be 4500-5500 feet MSL so any snow will be confined
to higher peaks.

The Monday-Tuesday system looks to be potentially more robust with
higher amounts of precipitation including for the lower elevations.
The steady precipitation could actually start Sunday evening or
early Monday morning which is what the NBM is depicting in its POP
forecast. QPF amounts are forecast to be .25-.50 inches in the lower
elevations and close to 1.00 inch along the Cascades and Idaho
Panhandle, where probabilities of exceeding 1.00 inch of QPF range
from 30-70%. With snow levels 4000-4500 feet, significant snow
accumulations could occur (50-60% chance) over the higher mountains.

On Wednesday there are some indications that temporary ridging could
occur ahead of the next storm system but the ensemble clusters are
split with the timing of the next trough- with half moving the next
system in during the day Wednesday. The NBM POP forecast favors this
faster solution with a high likelihood (50-80%) of rain and high
mountain snow continuing. 78


&&

.AVIATION...
06Z TAFS...VFR conditions are expected through most of the
evening. Short term ensembles are showing vis reductions for
sites KCOE, KGEG AND KSFF from 12-16Z Thursday is possible.
Valleys of Northern Washington and Idaho Panhandle has a better
chance of patchy fog development. Otherwise winds will be light
(10 kt or less) and just a few mid and high clouds are
anticipated. JDC

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
Confidence is low in the fog development. Continued dry air
intrusion has decreased the possibility of fog development
possibility.

-----------------------

Confidence descriptors:
Low - Less than a 30 percent chance
Moderate - 30 to 70 percent chance
High - Greater than a 70 percent chance

For additional probabilistic information for NWS Spokane airports,
please refer to the Aviation Dashboard on our webpage:
https:/www.weather.gov/otx/avndashboard

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        27  46  28  51  32  52 /   0   0   0   0  10  30
Coeur d`Alene  26  46  29  51  33  51 /   0   0   0   0  10  30
Pullman        26  49  29  53  33  53 /   0   0   0   0   0  30
Lewiston       31  51  34  56  37  58 /   0   0   0   0   0  30
Colville       17  44  21  49  25  48 /   0   0   0   0  10  40
Sandpoint      25  45  27  49  30  48 /   0   0   0   0  10  40
Kellogg        27  47  34  55  37  54 /   0   0   0   0  10  30
Moses Lake     24  49  26  50  30  50 /   0   0   0   0   0  30
Wenatchee      30  48  33  51  38  51 /   0   0   0   0  10  30
Omak           28  48  30  52  34  51 /   0   0   0   0  10  40

&&

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

$$