283
FXUS66 KOTX 190442
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
942 PM PDT Tue Jun 18 2024

.SYNOPSIS...
Scattered showers and thunderstorms will continue through the
early evening. Shower activity will return Wednesday afternoon
across the northern mountains. A warming trend is expected
through the week, with high temperatures rebounding into the mid
80s to mid 90s on Saturday. A dry cold front on Sunday will
elevated fire weather concerns with widespread breezy wind across
the region.

&&

.DISCUSSION...
Tuesday night: Radar imagery this afternoon shows weak thunderstorms
across much of northeast Washington, the far northern Idaho
Panhandle and across the north Cascades. SPC mesoanalysis depicts
250-500 J/kg of MUCAPE across these areas. With virtually no wind
shear, these storms are very short-lived with isolated lightning
strikes and a handful of small hail reports. These storms will
move to the east-southeast with some high resolution models
showing activity to move into the Spokane metro area over the next
couple hours. Showers will begin to diminish after sunset.

Wednesday and Thursday: The Inland Northwest will remain under a
broad Rex Block Pattern Wednesday and Thursday as a weak trough
sits over the western US and a ridge builds over western Canada.
850mb temperatures will warm as the trough weakens and the flow
aloft shifts back to the west-southwest. Diurnal showers will
return on Wednesday but coverage will be limited mostly to the far
northern mountains as the drier and warmer air moves in from the
south. Temperatures will warm into the mid 70s to low 80s on
Wednesday and into the upper 70s to upper 80s by Thursday. Models
are showing a thermally induced surface trough to nose north
across the Washington Cascades on Thursday, which will bring
breezy north to northeast winds across central Washington and the
Columbia Basin in the afternoon. /vmt

Friday through Tuesday: Split flow pattern with upper level ridging
to the north and trof to the south amplifies some and gets displaced
to the east as a low pressure system drags a trof with not much in
the way of moisture through Eastern Washington and North Idaho
Sunday. The result is a continuation of the warming trend peaking on
Saturday followed up with cooler and breezy conditions Sunday which
may bring fire weather concerns. In addition the forecast is
generally dry but not totally dry as minor pops remain in place for
spotty short lived light showers in the afternoon/early evening.
Monday is marked with general upper level trof thus marked with the
coldest temps of the seven day forecast. The upper level trof may
rebound somewhat into flat zonal flow Tuesday thus allowing for some
warming. In addition this early portion of the next workweek has
minor mention of shower and/or thunderstorm activity given the
somewhat conditionally unstable atmosphere the presence of the upper
level trof provides.
/Pelatti

&&

.AVIATION...
06Z TAFS: Weak impulses tracking NW to SE through the forecast
areas are keeping showers ongoing this evening despite the loss of
afternoon heating. Showers in the vcnty of Spokane-
Cd`A-Sandpoint-Colville will be capable of brief IFR to MVFR cigs
and breezy outflow winds near 25 mph.  As the showers taper off,
recent rainfall will bring a low threat for patchy fog or stratus
through 17z. This comes with low confidence given the time of year
but based on recent temperature-dewpoint trends, it will not take
much for development. Greatest risk for fog will be in the
sheltered northern valleys of NE WA and N ID around Colville,
Ione, Deer Park, and Priest Lake. KSFF did receive heavy rainfall
today increasing the risk there as well. Easterly winds could
transport the moist boundary layer into Spokane International.
Cumulus buildups will occur again on Wednesday afternoon with the
highest chances for showers and weak thunderstorms across the
northern mountains from Sandpoint to Colville to Omak and
Winthrop.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Confidence how the
rich boundary layer moisture will play out overnight and coverage
of fog. It is conceivable that some sites become IFR/LIFR if fog
forms on the terminals. Fog will have a hard time persisting after
16-17z given the June sun angle. /sb

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

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        43  75  48  82  52  85 /  20   0   0   0   0  10
Coeur d`Alene  42  72  47  80  51  82 /  30   0   0   0   0  10
Pullman        42  74  46  80  50  82 /   0   0   0   0   0  10
Lewiston       48  84  54  90  58  90 /   0   0   0   0   0  10
Colville       37  72  41  79  44  84 /  40  20   0   0   0  10
Sandpoint      41  69  44  78  48  80 /  40  20   0   0  10  20
Kellogg        44  71  49  79  54  79 /  40  10   0   0  10  20
Moses Lake     46  82  53  87  54  90 /   0   0   0   0   0   0
Wenatchee      52  80  56  85  59  90 /  20   0   0   0   0   0
Omak           46  78  51  84  53  90 /  30  20   0   0   0   0

&&

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

$$