724
FXUS66 KOTX 051754
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1054 AM PDT Wed Jun 5 2024

.SYNOPSIS...
The Inland Northwest will get a break from the wind Wednesday,
Thursday and Friday as high pressure builds over the region. The
weekend will be very warm with afternoon temperatures well into
the 80s and 90s. A weak weather system Saturday night into Sunday
looks to bring a chance for showers and possibly thunderstorms to
the region. Above normal temperatures continues into next week.

&&

.DISCUSSION...

Today through Saturday: Our trofy and active weather pattern will
transition to a zonal to flat ridge of higher pressure pattern
through Thursday. Drier air with yesterday`s cold front passage and
increased subsidence with higher heights aloft will cut off the
potential for additional precipitation. Temperatures will begin to
see a sharp warming trend: warming to near normal today and above
normal by Thursday. The pressure pattern aloft becomes more
amplified by Friday into Saturday as a low pressure trough over the
eastern Pacific digs and begins to pump up the ridge over the west.
Temperatures at 850 mbs will increase to between 17-20 degrees
Celsius by Friday and 20-23 degrees Celsius by Saturday. Translating
these temperatures down to the surface and we are looking at
widespread temperatures in the 80s by Friday and mid 80s to mid 90s by
Saturday. Below is the probabilities for greater than 85 degrees, 90
degrees, and 95 degrees off of the NBM for Saturday:

* 85 degrees - Spokane: near 100%, Sandpoint: 50-55%, Omak: near
  100%, Wenatchee: near 100%, Moses Lake: near 100%, Lewiston: near
  100%, Pullman/Moscow: 55-60%

* 90 degrees - Spokane: 60-65%, Sandpoint: < 5%, Omak: 90-95%,
  Wenatchee: 85%, Moses Lake: 90%, Lewiston: 95%, Pullman- Moscow:
  10-15%

* 95 degrees - Spokane: 10%, Sandpoint: near 0%, Omak: 30-35%,
  Wenatchee: 30-35%, Moses Lake: 50%, Lewiston: 50%, Pullman-Moscow:
  near 0%

Saturday night through Sunday night: Models begin to diverge
significantly for the latter half of the weekend. Ensembles are
clustering around a scenario in which a shortwave disturbance
rotates around the upper trough in the Gulf of Alaska, but there are
differences with the details and strength of this wave. The leading
consensus is for a weak shortwave that will draw up moisture from
the south and result in convection overnight Saturday into Sunday.
How strong this convection becomes is still a matter of question. It
will depend on the timing and strength of the disturbance. The 00Z
deterministic GFS solution is on the stronger side of the possible
envelope of solutions. It represents a scenario in which strong to
isolated severe thunderstorms is a possibility. It swings through
Sunday afternoon with a negative tilt and surface based CAPE up
around 1,000 J/kg. The ensembles are more subdued. Part of this
could just be because there are timing differences. However, both
the 00Z ECMWF and Canadian indicate a weaker shortwave disturbance,
so it is difficult to buy off on the operational GFS solution at
this point. There will be the potential for nocturnal convection
Saturday night. This will bring the risk for lightning. There`s
higher confidence for increased cloud cover, and this will act to
"lock" in the warmer afternoon temperatures. Low temperatures
Saturday night into Sunday night look to remain in the 60s. Warmer
spots such as Wenatchee, Lewiston, and Moses Lake will have a hard
time cooling below the upper 60s. The very warm temperatures on
Saturday with little relief Saturday night will increase the
potential for heat related impacts. This is especially so since it
will be the first little "heat wave" of the season and our bodies
haven`t gotten acclimated to the hear yet. Be prepared for a hot day
on Saturday if planning to be outdoors for an extended period,
especially during the peak heating hour of the afternoon; make sure
to keep hydrated and to seek cooler temperatures such as a well
ventilated and air conditioned building.

Monday through Wednesday: Model ensembles continue to exhibit
uncertainty further out into the extended. The ECMWF ensemble, which
has a weaker shortwave into the ridge over the weekend, maintains a
stronger ridge of higher pressure over the Northwest into next week.
It suggests only minimal cooling will take place on Sunday with very
warm temperatures potentially back into the mid 80s to mid 90s will
return. The GEFS and Canadian ensemble have a weaker ridge. The
Canadian is in the middle between the cooler GEFS and warmer ECMWF
ensemble. As such, the forecast resembles the middle of the road
Canadian. Confidence is high that temperatures will remain above
normal, but low on how much above normal. Confidence is low for
potential on showers/thunderstorms. It`s possible that we hold on to
enough moisture and instability during the afternoons for pop-up
convection over the higher terrain. /SVH

&&

.AVIATION...
18Z TAFS: VFR conditions across the Inland Northwest today as
high pressure builds. Lingering moisture will produce mountain
obscurations over the Cascade crest and in the Idaho Panhandle and
a scattered to broken stratus deck around KPUW and KLWS, resulting
in MVFR conditions at PUW. Dry air will work to clear this deck
over the next couple of hours. A weak weather system moving across
British Columbia will allow mid to high level clouds to stream
across the region tonight through Thursday morning.


FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
Confidence remains high for VFR conditions across most of the area
today.

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

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        68  45  79  52  84  56 /   0   0   0   0   0   0
Coeur d`Alene  67  45  77  51  82  56 /   0   0   0   0   0   0
Pullman        66  44  76  51  81  55 /   0   0   0   0   0   0
Lewiston       77  52  86  59  91  63 /   0   0   0   0   0   0
Colville       69  40  78  45  84  51 /   0   0   0   0   0   0
Sandpoint      66  43  74  48  81  52 /   0   0   0   0   0   0
Kellogg        64  48  75  54  81  58 /   0   0   0   0   0   0
Moses Lake     76  47  85  53  90  59 /   0   0   0   0   0   0
Wenatchee      76  51  84  58  89  65 /   0   0   0   0   0   0
Omak           76  47  83  53  88  57 /   0   0   0   0   0   0

&&

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

$$