530
FXUS66 KOTX 171754
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1054 AM PDT SUN MAY 17 2026
KEY MESSAGES
- SCATTERED SHOWERS WITH A 20 PERCENT CHANCE FOR AFTERNOON
THUNDERSTORMS THROUGH MONDAY AND MAINLY OVER THE MOUNTAINS.
- COOLER OVERNIGHT TEMPERATURES WILL BRING A THREAT OF MORNING FROST
SUNDAY AND MONDAY. THIS WOULD BE IMPACTFUL TO ANY SENSITIVE PLANTS
OR CROPS.
- CONDITIONS TREND DRIER AND WARMER THROUGH THE WORKWEEK.
SYNOPSIS
DIURNALLY FORCED SHOWERS WITH ISOLATED AFTERNOON THUNDERSTORMS
WILL CONTINUE THROUGH MONDAY. COLD OVERNIGHT TEMPERATURES WILL
BRING THE THREAT OF FROST IN THE MORNINGS ON SUNDAY AND MONDAY.
PRECIP CHANCES DECREASE AND AFTERNOON HIGHS TREND WARMER THROUGH
THE WORKWEEK, CLIMBING BACK INTO THE 70S AND 80S BY THURSDAY
HEADING INTO NEXT WEEKEND.
DISCUSSION
TODAY THROUGH THURSDAY NIGHT: A DEEP LONGWAVE TROUGH OF LOWER
PRESSURE WILL REMAIN OVER THE CONUS FOR THIS WEEKEND THROUGH THE
WORK WEEK. THE AXIS OF THIS LONGWAVE TROUGH WILL SLOWLY BUT SURELY
SHIFT EASTWARD FROM THE WEST THIS WEEKEND AND MIGRATE OVER THE
ROCKIES BY MONDAY THROUGH WEDNESDAY AND THEN OVER THE PLAINS BY
THURSDAY INTO FRIDAY. WE WILL REMAIN CONDITIONALLY UNSTABLE
TODAY AND DIURNAL HEATING WILL RESULT IN AN EXPANDING AREA OF
CONVECTIVELY FORCED SHOWERS THROUGH THE AFTERNOON. THERE WILL BE
A LACK OF SUPPORT ALOFT COMPARED TO SATURDAY WITH MORE WIDELY
SCATTERED CONVECTION EXPECTED OVER THE HIGHER TERRAIN. STEERING
FLOW WILL BE NORTHERLY WITH STORMS EXPECTED TO DRIFT OFF OF THE
NORTHERN MOUNTAINS INTO THE UPPER COLUMBIA BASIN AND OVER THE
SPOKANE AREA BY MID TO LATE AFTERNOON AND THE EVENING HOURS.
THUNDERSTORMS WILL FEATURE INFREQUENT CLOUD TO GROUND LIGHTNING
STRIKES, PEA SIZED HAIL, BRIEF DOWNPOURS, AND GUSTY WINDS UP TO
25-30 MPH. SPEAKING OF WINDS, THE MORNING HOURS FOR TODAY WILL
SEE BREEZY NORTHERLY WINDS DOWN THE OKANOGAN VALLEY SUSTAINED AT
15-20 MPH AND GUSTS UP TO 30 MPH. OTHERWISE, WINDS WILL BE
FAIRLY LIGHT OTHER THAN CONVECTIVELY INDUCED OUTFLOW WINDS.
THERE WILL BE LESS CLOUD COVER AS CONVECTIVE SHOWERS DECAY SUNDAY
NIGHT INTO MONDAY MORNING. LESS CLOUD COVER COMPARED TO THE PAST
COUPLE OF NIGHTS WILL INCREASE THE POTENTIAL FOR MORE RADIATIONAL
COOLING AND A BETTER POTENTIAL FOR THOSE COLDER MOUNTAIN VALLEYS TO
DROP DOWN NEAR TO OR BELOW FREEZING. THE METHOW VALLEY,
REPUBLIC, COLVILLE, DEER PARK, PEND OREILLE RIVER VALLEY, PRIEST
RIVER WILL ALL SEE THE POTENTIAL FOR TEMPERATURES OF DIPPING
DOWN INTO THE LOWER 30S INTO MONDAY MORNING. THE SPOKANE AREA
AND PALOUSE WILL ALSO SEE CHILLY TEMPERATURES WITH LOWS IN THE
MID TO UPPER 30S. IT WILL BE A GOOD IDEA TO BRING IN OR COVER
SENSITIVE PLANTS TO PROTECT THEM FROM FROST OR FREEZE DAMAGE.
AREAS THAT WILL CONTINUE TO SEE WEAK CONVECTIVE POTENTIAL FOR
CAPE VALUES UP TO 300-400 J/KG WILL BE THE NORTHERN MOUNTAINS
AND THE IDAHO PANHANDLE ON MONDAY. TEMPERATURES ALOFT DO WARM A
BIT MORE COMPARED TO TODAY WITH THE TROUGH AXIS SHIFTING A
LITTLE BIT FURTHER EAST. THIS WILL LIMIT CONVECTIVE POTENTIAL A
BIT WITH SHOWERS/THUNDERSTORM COVERAGE EXPECTED TO BE LESS
SUNDAY INTO MONDAY.
BY MID WEEK (TUESDAY THROUGH THURSDAY), I CANNOT COMPLETELY
RULE THE POTENTIAL FOR SHOWERS OR EVEN A ONE HIT WONDER
THUNDERSTORM, BUT THE POTENTIAL FOR CONVECTION WILL BE LIMITED
TO THE CLOSER TO THE CANADIAN BORDER IN NORTHEAST WASHINGTON
INTO THE IDAHO PANHANDLE. OTHERWISE, WE ARE LOOKING AT A DRYING
OUT AND GRADUAL WARM UP OF OUR TEMPERATURES FOR NEXT WEEK.
TEMPERATURES WARM UP ABOVE NORMAL BY WEDNESDAY WITH OUR HIGHS
BACK INTO THE 70S. THE RISK FOR MORNING FROST ALSO WILL DECREASE
AS TEMPERATURES SEE A SLOW WARM UP NEXT WEEK.
FRIDAY THROUGH SUNDAY: HEADING INTO NEXT WEEKEND, MODEL ENSEMBLES
ARE IN GOOD AGREEMENT WITH A SMALL AMPLITUDE RIDGE OF HIGHER
PRESSURE NUDGING IN OVER THE REGION OFF OF THE EASTERN PACIFIC. THIS
WILL FURTHER DECREASE OUR POTENTIAL FOR SEEING SHOWERS AND
CONTINUE THE UPWARD TREND IN OUR TEMPERATURES. EXPECT WIDESPREAD
HIGH TEMPERATURES IN THE UPPER 70S TO LOW 80S FOR NEXT WEEKEND. /SVH
AVIATION
18Z TAFS: DIURNALLY FORCED SHOWERS WITH ISOLATED THUNDERSTORMS
ARE EXPECTED FOR SUNDAY AFTERNOON AS SURFACE HEATING STEEPENS
LAPSE RATES ACROSS THE REGION. BEST CHANCES FOR SHOWERS (30 TO
50 PERCENT) AND THUNDERSTORMS (15 PERCENT) WILL BE ACROSS
EXTREME EASTERN WA AND NORTH ID INCLUDING KGEG, KSFF, KCOE,
KPUW, AND KLWS, THOUGH A FEW POP- UP SHOWERS CAN'T BE RULED OUT
ELSWEWHERE. OUTSIDE OF BRIEF, PASSING SHOWERS AND THUNDERSTORMS
SUNDAY AFTERNOON, VFR CONDITIONS ARE FORECAST TO PREVAIL FOR ALL
SITES OVER THE NEXT 24 HOURS.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
ALTHOUGH THERE IS A 30 TO 50 PERCENT CHANCE FOR SHOWERS ACROSS
MUCH OF EASTERN WASHINGTON AND NORTH IDAHO THIS AFTERNOON INTO
THE EARLY EVENING, THE PROBABILITY OF SHOWERS IMPACTING ANY ONE
SITE WAS TOO LOW TO INCLUDE IN THE TAFS.
-----------------------
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 63 38 66 41 68 43 / 20 20 0 0 0 0
COEUR D'ALENE 60 38 64 41 65 44 / 30 30 0 0 0 10
PULLMAN 57 36 62 39 64 41 / 20 20 0 0 0 0
LEWISTON 60 41 67 43 69 46 / 10 30 10 0 0 10
COLVILLE 68 33 69 36 70 38 / 20 20 10 0 10 0
SANDPOINT 60 37 63 40 64 42 / 20 30 20 0 10 10
KELLOGG 56 36 62 39 64 42 / 50 20 30 0 10 10
MOSES LAKE 70 41 73 42 74 45 / 0 20 0 0 0 0
WENATCHEE 70 46 72 48 73 50 / 0 10 10 0 0 0
OMAK 70 42 72 44 73 47 / 10 20 0 0 0 0
OTX WATCHES/WARNINGS/ADVISORIES
WA...NONE.
ID...NONE.
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