519
FXUS66 KOTX 302148
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
248 PM PDT Thu May 30 2024

.SYNOPSIS...
Overnight temperatures near to and below freezing is expected
again Friday morning. Drier weather Friday will occur with light
showers mainly over the mountains for Saturday. A dynamic storm
system will push across the region late Sunday into Monday
bringing widespread rain followed by gusty winds and the potential
for afternoon thunderstorms on Monday. Next week will see a
warming and drying trend and confidence is increasing for
temperatures warming into the 80s and 90s.

&&

.DISCUSSION...
Tonight: Another cold night is expected across the region. Ensemble
guidance has trended upward a degree or two. With poor verification
the last couple days, the forecast was lowered a couple of degrees
below guidance. The current highlights are fine and no adjustment
was made. One concerning areas is the Camas Prairie area.
Probability of freezing temps is still only around 20% in the area.
Some cold pockets that drop into the upper 20s. Overall the lows for
the night will be in the upper 20s and 30s.

Friday through Sunday: A ridge pattern will move over the region and
last through most of Sunday. There will be weak wave of moisture on
Saturday will bring light showers to the higher terrain with little
to no accumulation expected. A lesser chance of a stray shower
chance over the Basin is possible. The wave will bring breezy winds
to the Cascades Gaps and western portion of the Basin. Speeds will
generally be sustained in the teens and gusts up to 30 MPH. By
Sunday, the ridge breaks down as a Low begins to press into the
Pacific Northwest. Highs will be in the upper 60s and 70s. Lows will
be in the upper 30s and 40s. /JDC

...Beneficial rains for the Inland Northwest Monday...

Sunday night through Thursday: A large tap of Pacific moisture
moving along the base of a strong low pressure system will move
into the region beginning late Sunday and continue through Monday.
180-200% of normal precipitable water values will be widepsread
across the region. Precipitation chances will begin to increase
late Sunday afternoon and evening and continue through Monday.
Widespread rains are expected. We are still several days out, but
precipitation amounts are looking to be a tenth to a quarter of
an inch in the valleys and lower elevations of central WA; 0.40
to around an inch for the valleys of eastern WA and north ID; and
over an inch along the crest of the Cascades, and the mountains
of extreme northeast WA and the ID Panhandle. These rains will be
beneficial to the region, creating rises on local creeks, streams,
rivers and lakes. Some ponding of water is possible for areas
that do not have proper drainage. The time period to watch out for
will be Monday morning when precipitation amounts will be heavier
over a shorter period of time. Cannot rule out localized rock or
mud slides for the ID Panhandle, but at this time, the
probability looks low.

Monday windy conditions are expected in the afternoon and evening
hours. NBM is a bit slow to catch on to what MOS guidance is
showing. Have trended forecast towards the 90th percentile of the
NBM which has sustained winds of 20 to 30 mph and gusts 30 to 45
mph across much of central WA and onto the Palouse and Spokane
area. The more protected valleys of northeastern WA and north ID
will not see winds as strong as this.

With the good dynamics of this front moving through, if we can
get just a little bit of partial clearing, there will be afternoon
and evening thunderstorms. Currently, it does not appear the
trough is taking on a strong negative tilt, so our forecast of
20-30% chance of thunder is good for now.

Showers remain in the forecast for Tuesday as the ridge begins to
build to our south.

Temperatures will remain on the cool side with highs in the 60s to
around 70 through Tuesday.

Wednesday onward a ridge will build somewhere over the western
US. There are some discrepancies of where the ridge sets up, which
will directly impact how hot we will get. For now, plan on
warming conditions. By Thursday temperatures will be 7 to 10
degrees above average, which is 80s. Friday through the weekend we
could see temperatures warm further, with 90s for parts of central
WA and the LC Valley. Those who are not acclimated to these hot
temperatures for early June could experience heat exhaustion if
outside during the hottest times of the day. Those choosing to go
to bodies of water should be aware that the waters are still cold
and swift and could create hypothermia and difficulty swimming.
/Nisbet

&&

.AVIATION...
18Z TAFS: VFR conditions expected for TAF sites over the next 24
hours. Isolated to scattered showers are expected with cumulus
clouds over Northeast Washington and North Idaho Panhandle this
afternoon, especially near the Sandpoint and Bonners Ferry
and possibly Colville and Chewelah airports. Few to scattered
fair weather cumulus is expected across KGEG- KSFF-KCOE corridor
and on the Palouse (KPUW) and Lewiston- Clarkston Valley (KLWS).
Expect VFR conditions and westerly winds of 8-12 kts this
afternoon. Winds will calm overnight. Drier air will bring less
clouds and warmer temperatures for Friday.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
Confidence is high for VFR conditions for TAF sites. Low
confidence in thunderstorm developing over Northeast Washington
and North Idaho Panhandle fro the afternoon. /JDC

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

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        37  70  47  73  49  70 /   0   0   0   0   0  10
Coeur d`Alene  36  68  46  71  48  67 /   0   0   0   0  10  10
Pullman        36  67  47  69  48  68 /   0   0   0   0   0  10
Lewiston       43  76  51  79  55  75 /   0   0   0   0   0  10
Colville       32  71  42  70  42  69 /   0   0   0  20  20  20
Sandpoint      37  67  45  68  47  67 /  10   0   0  10  20  20
Kellogg        38  65  47  69  52  67 /   0   0   0   0  10  10
Moses Lake     37  76  50  79  48  72 /   0   0   0   0   0  10
Wenatchee      43  75  57  74  52  70 /   0   0   0   0   0  20
Omak           39  76  51  76  47  71 /   0   0   0  10   0  20

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Frost Advisory until 8 AM PDT Friday for Central Panhandle
     Mountains-Idaho Palouse-Northern Panhandle.

WA...Frost Advisory until 8 AM PDT Friday for Spokane Area-Upper
     Columbia Basin-Washington Palouse-Western Okanogan County.

     Freeze Warning until 8 AM PDT Friday for Northeast Mountains-
     Okanogan Highlands.

&&

$$