617
FXUS66 KOTX 302303
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
403 PM PDT SUN MAR 30 2025
SYNOPSIS
SHOWERS WILL SPREAD INTO THE REGION TONIGHT INTO MONDAY.
ISOLATED THUNDERSTORMS ARE POSSIBLE MONDAY AFTERNOON. COOL AND
UNSETTLED WEATHER PATTERN WILL PERSIST THROUGH MUCH OF THE
WEEK WITH A WARMING AND DRYING TREND BY THE WEEKEND.
DISCUSSION
TONIGHT - TUESDAY: A BROAD AREA OF LOW PRESSURE SPINNING OFF THE
COAST WILL WOBBLE INLAND DELIVERING SEVERAL ROUNDS OF SHOWERS AND
CONTINUED COOL CONDITIONS. AS OF 2PM, THE CENTER OF THE LOW WAS
BETWEEN 130-140W OFF THE COAST OF OREGON; SEVERAL EMBEDDED WAVES
EXTENDING FROM THE MOTHER LOW ARE EVIDENT ON WATER VAPOR WITH THE
FIRST BEGINNING TO LIFT THROUGH OREGON. THIS WILL DELIVER THE
FIRST ROUND OF SHOWERS TO THE INLAND NW LATE THIS EVENING AND
OVERNIGHT. CLOUDS WILL TRAP THE AFTERNOON WARMTH KEEPING SNOW
LEVELS BETWEEN 4500-5500 FEET. CONSEQUENTLY, LIGHT SNOW WILL BE
POSSIBLE ON THE MOUNTAIN PASSES AND ANYWHERE FROM 0.02-0.15"
RAINFALL IN THE LOWLANDS. AS THE LOW DRIFTS INLAND MONDAY, 500MB
TEMPS WILL COOL AROUND 4-5C, STEEPENING LAPSE RATES, AND
INCREASING THE THREAT FOR ADDITIONAL SHOWERS WITH ANY BREAKS IN
THE CLOUDS IN THE MORNING. MORE ORGANIZED BANDS OF SHOWERS WILL
DEVELOP ALONG ANOTHER EMBEDDED WAVE SWINGING INLAND AHEAD OF THE
MAIN LOW. THERE ARE SUBTLE DIFFERENCES IN THE MODELS IN TIMING OF
THIS FEATURE BUT LITTLE ARGUMENT OF ITS EXISTENCE. ISOLATED
THUNDERSTORMS WILL BE POSSIBLE ACROSS THE REGION ON MONDAY
AFTERNOON. HIGHEST PROBABILITIES VIA THE HREF/SREF CALIBRATED
THUNDER ARE FOCUSED OVER SOUTHEASTERN WA AND THE LOWER IDAHO
PANHANDLE AND PORTIONS OF THE NORTH-CENTRAL CASCADES. THE EUROPEAN
ENSEMBLE HIGHLIGHTS CENTRAL WA AND THE SW BASIN. THE DEPTH OF THE
CLOUDS AND LIGHTNING POTENTIAL WILL BE EXTREMELY DEPENDENT ON
WHERE WE SEE THE BEST BREAKS IN THE CLOUDS AND FEW HOURS OF
SUNSHINE. DUE TO WEAK SHEAR, THE MAIN THREATS FROM ANY CELLS WILL
BE LIGHTNING AND BRIEF DOWNPOURS OF RAIN, SMALL HAIL, AND GRAUPEL.
THE SECOND, AFOREMENTIONED WAVE MONDAY PM WILL STALL OVER SOUTHERN WA,
WEAKEN, THEN BEGIN TO DRIFT SOUTHWARD AS THE MOTHER OFFSHORE LOW
SWINGS INTO SOUTHERN OREGON AND BEGINS TO PULL THE WAVE BACK
SOUTH. MODELS ARE STRUGGLING WITH THE DETAILS OF THE PRECIPITATION
PLACEMENT WITH THIS WRAP AROUND BAND OF MOISTURE AS IT LOSES ITS
NORTHWARD PROGRESSION AND STARTS TO WEAKEN. THE SLOW NATURE OF
THESE FEATURES DOES BRING LOW PROBABILITIES FOR A 0.10" - 0.25" OF
LIQUID UNDER THEM. IF THIS SETUPS UP ON THE MOUNTAIN PASS, 2-3
INCHES OF SNOW IS POSSIBLE OVERNIGHT. IN THE LOWLANDS, IT WILL
LARGELY FALL AS RAIN INITIALLY BUT SNOW LEVELS WILL BE FALLING AS
LOW AS 2000 FEET OVERNIGHT WITH POTENTIAL FOR SLUSHY
ACCUMULATIONS. ADDITIONAL BREAKS IN THE CLOUDS TUESDAY AFTERNOON
WILL RESULT IN WIDELY SCATTERED HIT OR MISS SHOWERS. THIS WILL BE
UNORGANIZED CONVECTION WITH THE HIGHEST POPS OVER THE MOUNTAINS
AND SLIGHT CHANCE IN THE E BASIN. A SLIGHT UPTICK IN WEST TO
NORTHWEST WINDS WILL LIMIT SHOWER CHANCES IN THE LEE OF THE
CASCADES BUT WOULD NOT RULE IT OUT COMPLETELY GIVEN 500MB TEMPS OF
-27C STILL PRESENT ALOFT.
IT WILL BECOME BREEZY TUESDAY AFTERNOON WITH WIND SPEEDS OF 5-15 MPH
AND GUSTS UP TO 25 MPH. THE MOST PERSISTENT WINDS WILL COME
THROUGH THE CASCADE GAPS AND INTO THE WESTERN COLUMBIA BASIN.
TEMPERATURES OVER THE PERIOD WILL BE ON PAR WITH LATE MARCH
AVERAGES WITH HIGHS IN THE 50S AND LOWS IN THE 30S. /SB
WEDNESDAY THROUGH SUNDAY: AS WE MOVE INTO THE SECOND HALF OF THE
WEEK, ENSEMBLES ARE COMING INTO BETTER CONSENSUS THAT WE WILL SEE
WARMER TEMPERATURES AND DRIED CONDITIONS TO END THE FIRST WEEK OF
APRIL. WEDNESDAY WE WILL SEE A SHORTWAVE PASS OVER THE REGION, WITH
SOME SHOWERS MAINLY OVER THE MOUNTAINOUS TERRAIN, WITH SIMILAR
CONDITIONS EXPECTED THURSDAY AS WELL. PRECIPITATION TOTALS WILL BE
LIGHT WITH ANY SHOWER. WITH SOME AVAILABLE CAPE IN THE ATMOSPHERE, A
SLIGHT CHANCE OF THUNDERSTORMS WAS ADDED TO THE FORECAST FOR
WEDNESDAY AFTERNOON IN THE NORTHERN WA MOUNTAINS AND ID PANHANDLE.
LATE THURSDAY IS WHEN THE RIDGE STARTS TO SLIDE INTO THE REGION AND
WILL CONTINUE TO STRENGTHEN THROUGH THE WEEKEND.
HIGH TEMPERATURES THIS TIME OF YEAR RANGE FROM THE LOW TO UPPER 50S
WHICH IS WHAT THE REGION WILL SEE WEDNESDAY. TEMPERATURES BEGIN TO
WARM STARTING THURSDAY, WARMING ROUGHLY 5 DEGREES EACH DAY THROUGH
AT LEAST SUNDAY. BY SUNDAY, UPPER 60S TO LOW 70S WILL BLANKET THE
REGION. /KK
AVIATION
00Z TAFS: VFR WITH LOCALLY BREEZY EASTERLY WINDS THROUGH 03Z.
AFTER 03Z, A BAND OF LIGHT RAIN SHOWERS WILL MOVE SOUTH TO NORTH
THROUGH THE FORECAST AREA REACHING THE CANADIAN BORDER AROUND 08Z.
A SECOND AND/OR THIRD BAND OF SHOWERS COMES ON ITS HEELS WITH
POTENTIAL FOR ONLY 1-3 HOURS OF A BREAK BETWEEN. A PERIOD OF MVFR
CIGS IS FORECAST BY THE HREF COMING UNDER ANY OF THE BANDS WITH
THE HIGHEST PROBABILITIES WITH THE MORNING BAND GIVEN THE TIME OF
DAY. TIMING OF THESE BANDS WILL BE CHALLENGING. THE ATMOSPHERE
ALSO BECOMES INCREASINGLY UNSTABLE ON MONDAY WITH COOLING ALOFT.
LOOK FOR SHOWERS TO DEEPEN IN DEPTH WITH POTENTIAL FOR ISOLD
LIGHTNING STRIKES. THE DEGREE OF BREAKS IN THE CLOUDS WILL PLAY A
LARGE ROLE IN WHETHER ANY SITE RECEIVES LIGHTNING OR NOT. BRIEF
DOWNPOURS AND LOCAL MVFR CONDITIONS POSSIBLE UNDER HEAVIER CELLS.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: HIGH CONFIDENCE
FOR VFR CONDITIONS THROUGH 06Z. MODERATE CONFIDENCE AFTER AS
LOWERING CLOUD DECK COULD CREATE MVFR CONDITIONS. THERE IS A
30-60% CHANCE FOR MVFR CONDITIONS AT SFF, COE, PUW BETWEEN MONDAY
08-14Z. AS MENTIONED ABOVE, THERE IS CONSIDERABLY UNCERTAINTY WITH
THE DURATION OF A BREAK BETWEEN BANDS OF SHOWERS. SOME MODELS
BRING ADDITIONAL SHOWERS THROUGH 15-19Z, OTHERS ARE DRY UNTIL A
MORE ORGANIZED BAND AROUND OR AFTER 18Z. /SB
-----------------------
CONFIDENCE DESCRIPTORS:
LOW - LESS THAN A 30 PERCENT CHANCE
MODERATE - 30 TO 70 PERCENT CHANCE
HIGH - GREATER THAN A 70 PERCENT CHANCE
PRELIMINARY POINT TEMPS/POPS
SPOKANE 41 52 34 52 35 51 / 70 50 20 20 10 30
COEUR D'ALENE 40 51 34 50 34 49 / 80 60 40 40 20 60
PULLMAN 41 50 33 49 35 47 / 80 70 30 30 20 50
LEWISTON 45 56 37 55 39 55 / 50 70 30 20 20 30
COLVILLE 38 51 33 52 32 52 / 70 80 30 30 10 50
SANDPOINT 38 49 35 48 35 47 / 70 90 50 60 30 80
KELLOGG 39 48 33 46 37 44 / 80 80 50 60 30 80
MOSES LAKE 42 57 36 58 35 58 / 60 20 10 10 0 0
WENATCHEE 41 54 35 57 37 55 / 80 30 10 10 0 10
OMAK 42 56 35 57 34 57 / 70 70 30 10 0 10
OTX WATCHES/WARNINGS/ADVISORIES
ID...NONE.
WA...NONE.
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