223
FXUS66 KOTX 261203
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
503 AM PDT FRI APR 26 2024
SYNOPSIS
FRIDAY WILL FEATURE ANOTHER ROUND OF SHOWERS, SOME CAPABLE OF
THUNDER IN THE NORTHERN MOUNTAINS AND ID PANHANDLE. THE WEEKEND
AND EARLY NEXT WEEK WILL FEATURE SHOWERY WEATHER OVER THE
MOUNTAINS AND SEASONABLY COOL TEMPERATURES. SUNDAY AND MONDAY HAVE
THE POTENTIAL TO BE WINDY WITH THE PASSAGE OF A FRONTAL SYSTEM.
DISCUSSION
SHOWERS WILL PERSIST THROUGH MUCH OF THE DAY AS A SURFACE LOW OFF
THE WA COAST SLOWLY MOVES INLAND. MODELS INDICATE A SLIM CHANCE
(15%) OF THUNDER WITH SOME SURFACE BASED INSTABILITY BUILDING IN THE
NORTHERN MOUNTAINS, PANHANDLE, AND SE WA LATE THIS MORNING INTO THE
EARLY AFTERNOON. LOOKING AT SOME SHORT-RANGE ENSEMBLE SOUNDINGS, I
AM NOT SOLD ON ANY STRIKES GIVEN THE HUGE DIFFERENCES OF INSTABILITY
BETWEEN THE SURFACE BASED PARCEL AND A MIXED LAYER PARCEL. POCKETS
OF HEATING FROM THE SUN WILL SPARK SHOWER ACTIVITY NONETHELESS.
THE UPPER LOW QUICKLY MOVES SOUTH OF OUR AREA TONIGHT BUT ANOTHER
SHORTWAVE MOVING IN BRINGING ADDITIONAL CHANCES OF SHOWERS TO THE
REGION FOR SATURDAY. MODELS INDICATE A SLIM CHANCE (15%) OF THUNDER
WITH SOME SURFACE BASED INSTABILITY BUILDING IN THE NORTHERN
MOUNTAINS SATURDAY, BUT AGAIN, NOT SOLD ON THIS POTENTIAL GIVEN HOW
LITTLE INSTABILITY THERE IS FOR A MIXED LAYER PARCEL. /BUTLER
SUNDAY - TUESDAY: THE START OF THE NEW WEEK WILL COME WITH SEVERAL DAYS
OF WINDY CONDITIONS, COOLING TEMPERATURES, AND PERIODS OF
SHOWERS...ESPECIALLY IN THE MOUNTAINS. MIDLEVEL FLOW ON SUNDAY
WILL START OFF WESTERLY THEN BEGIN TO BUCKLE TO THE SOUTHWEST AS A
DEEPER LOW CARVES INTO THE MEAN TROUGH. A STRENGTHENING SURFACE
LOW EAST OF CANADIAN ROCKIES WILL RESULT IN INCREASING SOUTHERLY
WINDS THROUGH THE DAY. WINDS HAVE DECREASED SLIGHTLY FROM EARLIER
RUNS BUT STILL ARE NOTICEABLY BREEZY TO GUSTY WITH SUSTAINED WINDS
OF 10-20 MPH AND GUSTS UP TO 30 MPH. THE COLD CORE SHORTWAVE
SWINGS INTO THE NORTHWEST SUNDAY NIGHT AND MONDAY WITH CONTINUED
WINDY CONDITIONS. WINDS CONTINUE TO BE DRIVEN BY A STRONG PRESSURE
GRADIENT TOWARD LOWER PRESSURE OVER SOUTHERN ALBERTA AND FURTHER
ENHANCED WITH COLD AIR ADVECTION. WIND DIRECTION WILL BECOME MORE
WESTERLY WITH TIME AS WELL, ESPECIALLY INTO MONDAY AFTERNOON.
BASED ON PROBABILITIES FOR SUSTAINED WIND SPEEDS OF 20 MPH OR
GREATER - SUNDAY AND MONDAY INDICATE VERY LITTLE DIFFERENCE (BOTH
AROUND 40%) FOR MUCH OF THE CENTRAL COLUMBIA BASIN. THE MAIN
DIFFERENCE WILL BE THE DIRECTIONAL CHANGE FROM SOUTH/SOUTHWEST TO
SOUTHWEST/WEST. MAJORITY OF THE EUROPEAN MEMBERS SUGGEST THE GUSTS
WILL BE SEVERAL MPH HIGHER FOR MONDAY VS SUNDAY FOR LOCATIONS
LIKE WENATCHEE, MOSES LAKE, PULLMAN, AND SPOKANE. FOR THE OKANOGAN
VALLEY, SUNDAY LOOKS BE THE WINDIEST DAY GIVEN THE ALIGNMENT WITH
THE NORTH TO SOUTH VALLEY. IN GENERAL WIND GUSTS OVER THE TWO
DAYS WILL PEAK AROUND 30-35 MPH YET SOME ISOLATED GUSTS AROUND 45
MPH CANNOT BE RULED OUT WITH THE SHORTWAVE PASSAGE SUNDAY NIGHT
AND MONDAY ON THE HIGHER BENCHES AROUND WENATCHEE, WATERVILLE
PLATEAU, AND IN THE FOOTHILLS OF THE BLUE MOUNTAINS. WESTERLY
WINDS REMAIN BREEZY ON TUESDAY BUT SPEEDS ARE ROUGHLY 1/2 OF THOSE
FROM MONDAY.
CURRENT THINKING IS SUNDAY WILL PROVIDE A PERIOD OF DRYING FROM THE
RECENT RAINFALL AND MONDAY COULD BE THE DAY MOST VULNERABLE TO
PATCHY BLOWING DUST IN THE WESTERN COLUMBIA BASIN. WE KNOW
AGRICULTURE PRACTICES ARE IN FULL SWING FOR PLANTING BUT
PREDICTING BLOWING DUST ALWAYS COMES WITH LOW CONFIDENCE,
ESPECIALLY WITHOUT VERY WARM AND DRY CONDITIONS DURING THE WINDS.
IN REGARDS TO PRECIPITATION, SCATTERED SHOWERS WILL MAINLY FOCUS OVER
THE CASCADE CREST AND INTO THE RISING TERRAIN OF NORTHEASTERN WA
AND NORTH IDAHO. SHOWERS WILL EXPAND AT TIMES INTO THE EASTERN
BASIN AND PALOUSE WITH THE GREATEST THREAT COMING WITH THE
SHORTWAVE PASSAGE SUNDAY NIGHT AND MONDAY. A FEW LIGHTNING STRIKES
WILL ALSO BE POSSIBLE WITH WEAK THUNDERSTORMS IN THE AFTERNOON.
SNOW LEVELS WILL BE CRASHING CLOSER TO 3000-3500 FEET SUNDAY NIGHT
AND MONDAY AS 850MB TEMPERATURES DROP NEAR 0C. CONSEQUENTLY, SNOW
IS LIKELY TO FALL ALONG THE CASCADE PASSES. FORECAST HAS 4-6
INCHES OF SNOW AT STEVENS PASS AND 2-4 INCHES AT WASHINGTON PASS
FROM SUNDAY EVENING THROUGH MONDAY MORNING. THOSE VENTURING ACROSS
THE PASSES SHOULD BE PREPARED FOR WINTER TRAVEL CONDITIONS DURING
THIS TIME. ADDITIONAL SNOW SHOWERS WILL CONTINUE MONDAY BUT THE
APRIL SUN ANGLE OFFERS LITTLE HOPE FOR SNOW TO ACCUMULATE ON ROADS
AFTER 9-10AM. IT NOT BE AS SNOWY AT LOOKOUT PASS DURING THIS
TIME-FRAME WITH ONLY AN INCH PREDICTED SUNDAY NIGHT INTO MONDAY
MORNING THOUGH CONDITIONS COULD CHANGE SO BE SURE TO UP TO DATE IF
TRAVELING EARLY MONDAY MORNING.
MONDAY WILL BE THE COOLEST DAY OF THE PERIOD WITH MOST COMMUNITIES
ONLY REACHING THE 50S AND A HANDFUL OF LOW 60S IN THE LOWER
BASIN. SUNDAY AND TUESDAY WILL BE MORE SEASONAL WITH UPPER
50S-60S. THOSE WITH SENSITIVE PLANTS MAY WANT TO KEEP AN EYE ON
TUESDAY MORNING LOWS NEAR FREEZING WITHIN THE MOUNTAIN VALLEYS AND
ACROSS THE UPPER BASIN.
WEDNESDAY - FRIDAY: THERE IS A 70% CHANCE THAT SHORTWAVE RIDGING
ARRIVES WEDNESDAY. THIS SCENARIO WILL PROMOTE LIGHT
EAST/SOUTHEAST WINDS AND TEMPERATURES IN THE 60S. A FEW SHOWERS
WILL LINGER IN THE IDAHO PANHANDLE WHILE THE CASCADES DRIES OUT.
THE OTHER 30% OF THE ENSEMBLES SAY NO-NO AND THE TROUGH WILL
PERSIST WITH COOLER TEMPERATURES AND MORE WIDELY SCATTERED
AFTERNOON SHOWERS. FOLLWING WEDNESDAY 60% OF THE ENSEMBLE MEMBERS
SHOWING ANOTHER TROUGH INTO THE NORTHWEST WHILE THE OTHER 40% ARE
IN SOME SORT OF TRANSITION FROM RIDGE TO TROUGH. ANY BLENDED
FORECAST APPROACH LIKE THE NBM IS EXPECTED TO STRUGGLE RESOLVING
THESE DETAILS AND IT'S DIFFICULT TO EXTRACT DETAILS IN THE
FORECAST. IF THE TROUGH WAS TO REMAIN OFF THE COAST, TEMPERATURES
WILL BE WARMER THAN FORECAST AND THE OPPOSITE CAN BE SAID IF THE
TROUGH COMES INLAND. THESE DIFFERENCES WILL ALSO IMPACT THE
FORECASTED PRECIPITATION CHANCES. NEEDLESS TO SAY, THERE IS A LOT
OF UNCERTAINTY WITH THE DETAILS FOR LATE NEXT WEEK SO STAY TUNED.
/SB
AVIATION
12Z TAFS: MVFR CONDITIONS ARE PROJECTED THROUGH THE MORNING, THEN
CONDITIONS IMPROVE TOWARD VFR WITH ADDITIONAL SHOWER CHANCES
EXPANDING. TOWARD CENTRAL WA, INCLUDING MWH AND EAT AND OMK, LOOK
FOR MAINLY VFR CONDITIONS.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
MODERATE CONFIDENCE IN MVFR CIGS OVER GEG/SFF/COE/PUW/KLWS FRIDAY
MORNING.
-----------------------
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 60 42 61 40 59 40 / 30 20 20 10 10 20
COEUR D'ALENE 58 42 59 41 56 39 / 50 20 40 20 20 30
PULLMAN 58 40 58 39 57 38 / 40 20 20 10 10 40
LEWISTON 64 46 65 46 65 45 / 40 20 10 10 0 30
COLVILLE 60 38 61 36 59 36 / 70 50 70 30 30 50
SANDPOINT 55 42 57 41 53 40 / 70 40 70 40 60 60
KELLOGG 56 43 56 43 53 40 / 70 50 70 30 60 60
MOSES LAKE 66 40 66 40 65 40 / 10 10 0 0 0 0
WENATCHEE 63 44 62 42 61 40 / 40 30 0 0 0 10
OMAK 63 43 66 39 63 39 / 50 40 20 10 0 10
OTX WATCHES/WARNINGS/ADVISORIES
ID...NONE.
WA...NONE.
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