819
FXUS66 KOTX 041140
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
440 AM PDT Sat May 4 2024

.SYNOPSIS...
It will be mild today with highs in the 60s and low 70s while
bands of rain spread into central Washington. Rain will be
widespread on Sunday as a slow moving low moves through the
Pacific Northwest. As the low pulls out of the region, look for
cool, showery, and brisk conditions Monday and Tuesday. Warmer and
drier weather will likely arrive late next week.

&&

.DISCUSSION...

Today through Monday afternoon: The start of the weekend will be
mild, cloudy, and breezy thanks to a low pressure moving towards
northern California. Along with that, rain chances increase in
central Washington through the morning into the afternoon hours.
Eventually chances for measurable rain spread into Eastern
Washington this evening and overnight.

Model disagreement is quite high still for the wrap around
precipitation band Sunday morning in eastern Washington. There is
a 60% chance of greater than 0.10 of an inch of rain from midnight
through noon Sunday. 3-7 am Sunday appears the most favorable
time for the deformation band to move through Spokane, although
some models indicate a light rain lasting through much of the day.
Unsurprisingly, ensemble members with less rain warm temperatures
up slightly faster during the morning. There is a 75% chance of
temperatures not exceeding 45 degrees through noon Sunday. While
the rain will be beneficial for dryland farmers in the Palouse and
West Plains after a dry April, outdoor activities on Sunday will
be dampened by the rain and cooler temperatures.

Monday will feature cooler temperatures compared to the norm,
accompanied by showers and localized windy conditions. The
departing low pressure system from the weekend will set up a tight
westerly pressure gradient across the Cascades on Monday,
resulting in gusty winds. According to ECMWF ensembles, wind
gusts up to 35 mph are anticipated on Monday, with 50-70 percent
of ensemble members forecasting gusts of 35 mph or higher across
eastern Washington.

Monday night through Tuesday night:  Brisk and showery. Northwest
flow aloft prevails over the Inland NW as the slow moving low
tracks into MT and a secondary weaker trough brushes in from the
Pacific. Showery precipitation decreases Monday evening while
brisk westerly winds persist through the night. A surface trough
over eastern WA keeps pressure gradients packed, leading to wind
gusts of 35-40 mph are possible in the lee of the Cascades and
Palouse. The winds relax slightly Tuesday morning and shift from
the west to northwest by the afternoon hours with higher gusts
returning again across central WA into the Palouse. Showery
conditions redevelop Tuesday afternoon and evening although with
less coverage and mainly for extreme eastern WA into north ID.
Snow level take a dip during the overnight hours with light snow
accumulations in the central Cascades, Blue mountains, and
Panhandle mountains. It will on the cool side with daytime
temperatures in the 50s to lower 60s and overnight lows in the mid
30s to lower 40s. db

Wednesday through Saturday: Drier and warmer. An upper level
ridge builds over the eastern Pacific and builds inland. Still
can anticipate a threat of showers over north Idaho for Wednesday,
but trending less coverage for Thursday as drier and more stable
conditions arrive. Winds decrease and shift from the north and
east. Under lighter winds, the more noticeable change will be
warmer temperatures reaching the 60s to lower 70s on Thursday and
in the 70s to lower 80s by Friday into Saturday. /rfox.

&&

.AVIATION...
12Z TAFS: Mid to high level clouds will continue to increase
across the Inland NW and gradually lower this afternoon and
evening as bands of precipitation move up from the south. Light
rain is expected across the Cascades by the morning hours on
Saturday with rain at KEAT by 16Z with local MVFR ceilings. South
and easterly winds will pick up with the front approaching. KPUW-
KGEG- KCOE will see the potential for gusts up to 25 kts into
Saturday morning with the easterly pressure gradient tightening
up. Rain bands will increase across KLWS, KPUW, KCOE to KGEG after
05Z.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence for
VFR conditions through Saturday night except for at KEAT where
confidence is moderate. The HREF/NBM model guidance for KEAT
indicates a 60% chance ceilings lower down to 3 kft. Chances for
MVFR ceilings expand early Sunday morning to KLWS, KPUW, and KGEG.
/rfox.

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

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        70  42  50  39  58  36 /  10  60  90  80  40  20
Coeur d`Alene  68  45  51  39  53  36 /  10  30  90  80  70  30
Pullman        66  39  46  37  52  35 /  10  90  90  80  60  40
Lewiston       72  46  56  43  61  41 /  10  90  90  80  60  30
Colville       68  42  59  38  59  34 /  20  20  60  80  70  40
Sandpoint      66  45  53  39  55  38 /  10  20  70  80  80  50
Kellogg        66  46  50  40  49  38 /  10  20  70  90  90  60
Moses Lake     69  45  61  41  62  38 /  30  70 100  40  10   0
Wenatchee      63  49  62  44  59  41 /  70  60  90  30  20  10
Omak           68  48  69  43  62  38 /  30  30  40  40  20  10

&&

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

$$