Lewiston, Idaho 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

698
FXUS66 KOTX 301741
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1041 AM PDT Sun Mar 30 2025

.SYNOPSIS...
A generally quiet weather day is expected for Sunday. Another
round of more widespread shower activity spreads into the region
Sunday Night into Monday. Thunderstorms are possible over extreme
Eastern Washington and North Idaho Monday afternoon, with a cool
and unsettled weather pattern persisting through much of the
week.

&&

.DISCUSSION...
Today and Monday: The Inland Northwest will see a fairly nice
Sunday as a Low begins to press into the Pacific Northwest.
Increasing clouds are expected through the afternoon and evening
as upper level moisture increases with the approaching Low.
Starting Sunday night, a band of showers will begin move South to
North across the Inland Northwest. Ensembles have increased the
850mb temperatures from previous runs. It has lead to higher snow
levels and lower snow amounts for the mountain passes from
previous forecast. Guidance currently have the passes receiving
less than an inch of snow through Monday morning. Probability of
an inch of snow for the passes are 38% for Stevens, 88% for
Sherman, and 88% for Lookout through early Monday morning. The
shower activity will continue through Monday for the region. Most
locations can expect near amounts of a tenth or two of rain.
Heavy precip amounts of 0.25-0.5" for the Northern WA mountains,
Southeast WA, and Lower Idaho Panhandle. The short term models
have increased the instability for extreme Eastern WA and ID
Panhandle late Monday morning and afternoon. Cape values are
~200J/kg with decent shear. Slight chance of thunderstorms has
been added to these areas for Monday. Main impacts will be
lightning and gusty winds. Highs will be in the upper 40s and 50s.
Lows will be in the 30s and low 40s. /JDC

Tuesday through Thursday: The region remains under the influence
of a longwave trough resulting in continued cool and showery
weather. Snow levels drop as low as 2000-2500 feet during the
morning hours with afternoon snow levels 3000-4000 feet. Overall
models are not showing any organized disturbances within the
trough and thus showers are expected to be most pronounced during
the afternoon/evening hours, and over the mountains. The one
possible exception is Thursday, with about 25% of the ensembles
showing a deeper low over the area which if it comes to fruition
would have the potential of producing more significant
accumulations in the mountains, with some lowland snow possible
too above 2000 feet Thursday morning. But given only 25% of the
ensembles are in this camp the forecast leans towards similar
conditions on Thursday as Tuesday and Wednesday.

Friday and Saturday: Ensembles are in good agreement that an upper
ridge will build over the region bringing a significant warming
and drying trend. 80% of the ensembles suggest the warming will
continue into early next week. Next weekend looks to feature an
abundance of sunshine with high temperatures warming into the
upper 50s and 60s on Saturday, and then some locations surpassing
70F once again early next week. JW

&&

.AVIATION...
18Z TAFS: High clouds are streaming into the region from the
southwest ahead of an approaching weather system. 3-5Z, chances
for precipitation will increase starting in the southern portions
of our forecast area, including KEAT, KMWH, KPUW, KLWS then
spreading north into KGEG, KSFF, and KCOE 7-9Z. There is a 50% or
greater for ceilings to lower to MVFR or lower for Pullman,
Spokane, Coeur d`Alene, and points northward into Sandpoint and
Colville. As the initial band of rain lifts northward, there is
considerable uncertainty with the timing of a second band
developing on its heels but additional showers and 40% chance for
scattered MVFR cigs will follow. The timing of these bands will
dictate the amount of instability Monday afternoon and potential
for thunderstorms mainly 20-02z Monday afternoon. Locally breezy
easterly component wind will also impact sites from KCOE to KMWH
with speeds 10-15 mph at times.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
for conditions to remain VFR through 06Z. Moderate confidence
after as lowering cloud deck could create MVFR conditions. There
is a 30-60% chance for MVFR conditions at SFF, COE, PUW between
Monday 08-14z. As mentioned above, there is considerably
uncertainty with the duration of a break between bands of showers.
Some models bring additional showers through 15-19z, others are
dry until a more organized band around or after 18z.  /sb

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

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        58  41  52  35  52  35 /   0  70  70  20  30  10
Coeur d`Alene  57  40  51  35  50  33 /   0  70  80  40  50  20
Pullman        55  41  50  34  49  34 /   0  70  80  30  50  30
Lewiston       62  45  56  38  55  39 /   0  50  80  30  40  30
Colville       57  38  51  34  52  31 /   0  70  80  30  40  20
Sandpoint      55  38  49  35  48  34 /   0  80  90  50  70  30
Kellogg        53  39  48  34  46  36 /  10  70  90  40  70  30
Moses Lake     62  42  57  36  58  35 /   0  50  30  10  10   0
Wenatchee      57  41  54  36  56  37 /  10  70  40  10  10   0
Omak           61  42  56  36  57  34 /  10  70  70  20  20   0

&&

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

$$