280
FXUS66 KOTX 191140
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
440 AM PDT Sat Apr 19 2025

.KEY MESSAGES...

- Isolated afternoon thunderstorms over northeast Washington
  and in the Idaho Panhandle Saturday, Sunday and Monday.

&&

.SYNOPSIS...
Today through Monday will see seasonable temperatures along
with chances for showers and isolated thunderstorms over
northeast Washington and in the Idaho Panhandle. Warm and dry
conditions are expected to return toward the middle of next
week.

&&

.DISCUSSION...
Today and Tonight: A cold front will slide across the Inland
Northwest. It will be relatively weak, but will bring renewed
moisture to the region after a period of very dry conditions.
Morning radar returns at 2AM shows weak echoes forming east of
the Cascades along the frontal band. So far this moisture is
likely mostly producing virga as the atmosphere continues to
moisten from the top down. A modest P-Wat plume up to between
0.5-0.8 inches will mostly go towards moistening up the
atmosphere rather than seeing any appreciable precipitation.
Best chances for more than a few hundredths of an inch of rain
will be in the mountains of northeast Washington and in the
Idaho Panhandle through this morning into the early afternoon.
The atmosphere then destabilizes with scattered showers and up
to a 15% chance for thunderstorms over the Northeast Mountains
and in the Northern Panhandle. Instability parameters only
support isolated thunderstorms with infrequent lightning with
surface based CAPEs of up to between 100-200 J/kg. The westerly
cross Cascade gradient will tighten up with winds becoming
breezy through the Cascade gaps. The Chelan area down to
Wenatchee and the Waterville Plateau are expected to see wind
gusts up to 20-30 mph for the late afternoon and evening hours.

Sunday through Monday: Behind the cold front will be a trough
of lower pressure that digs in over the region. The atmosphere
will be conditionally unstable with periods of showers and
afternoon thunderstorms. Best chances for thunderstorms with up
to a 15-20% chance will be over northeast Washington into the
Idaho Panhandle. Better synoptic scale forcing with a shortwave
disturbance rounding the trough will occur Sunday, but Monday
will see more favorable instability. Showers will be more widely
scattered in the afternoon with diurnal heating destabilizing
the lower levels of the atmosphere. Showers and thunderstorms
won`t be particularly impactful but will be capable of producing
gusty winds, small hail, and infrequent cloud to ground
lightning strikes. Temperatures Sunday into Monday will be
cooler and slightly below average for mid April. /SVH

Monday night through Friday: Conditions look to turn drier again
for the middle of next week. Daytime temps to be near normal
for Tuesday, then expected to warm to above normal for
Wednesday, Thursday, and potentially beyond. Extended range
models trending to increase chances for precipitation Friday,
though finer details in this scenario likely to evolve in the
coming days. /KD

&&

AVIATION...
12Z TAFS: A narrow band of rain will develop along a cold front
this morning. Rain will be brief in the lee of the Cascades
through 17Z. Light rain is expected for a 3-6 hour period over extreme
eastern Washington and into the Idaho Panhandle between 15-21Z.
Ceilings will lower with added moisture in the boundary layer
producing MVFR conditions in the Idaho Panhandle by 17Z and
continues into the early afternoon. Ceilings will slowly lift
giving way to a weakly unstable atmosphere producing showers
through the rest of the afternoon into the evening. A few
showers may also develop into a brief thunderstorm. Breezy west
winds across the basin this afternoon with cold front passage.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: There is a
60-80% chance for MVFR ceilings to develop with rain today from
Colville (KCQV) into north Idaho including at Sandpoint (KSZT)
and Coeur d`Alene (KCOE). Chances are less than 30% for ceilings
below 3 kft in Spokane (KGEG) and Pullman/Moscow (KPUW). /SVH

-----------------------
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        38  56  36  56  34  60 /   0  10  10  30   0   0
Coeur d`Alene  36  54  35  53  32  58 /  20  10  20  60  10   0
Pullman        37  53  36  51  32  55 /   0  10  40  40   0   0
Lewiston       41  61  42  60  37  62 /   0   0  20  30   0   0
Colville       35  56  31  57  30  60 /  30  30  40  30  10   0
Sandpoint      38  54  36  52  31  57 /  40  40  50  80  20  10
Kellogg        38  51  38  48  34  54 /  30  30  40  90  20  20
Moses Lake     38  63  37  62  35  63 /   0   0   0   0   0   0
Wenatchee      42  61  39  61  37  62 /   0   0   0   0   0   0
Omak           38  62  35  61  34  63 /   0  10  10   0   0   0

&&

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

&&

$$