252
FXUS66 KOTX 150721
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1221 AM PDT SUN MAR 15 2026
KEY MESSAGES
- INCREASING CLOUDS WITH LIGHT MOUNTAIN SNOW SUNDAY NIGHT.
- DRIER AND WARMER NEXT WEEK IN THE LOWLANDS.
- RAIN ON SNOW IN THE CASCADES NEXT WEEK INCREASES HYDROLOGY
CONCERNS.
SYNOPSIS
CLOUDS INCREASE TODAY WITH CHANCES FOR LIGHT SNOW LATE IN THE
DAY. A WARMER AND OCCASIONALLY BREEZY PATTERN SETTLES IN FOR
MUCH OF THE WORK WEEK. PRECIPITATION, MODERATE TO HEAVY AT TIMES
WILL BE POSSIBLE ALONG THE NORTHERN CASCADES WITH INCREASING
CONCERNS FOR RISES ON RIVERS. LIGHTER PRECIPITATION WITH SNOW
MELT WILL LEAD TO ADDITIONAL RISES IN THE IDAHO PANHANDLE.
DISCUSSION
SUNDAY: A WARM FRONT WILL BE USHERED INLAND OVER THE NEXT 24 HOURS,
COMING ON THE EASTERN SHOULDER OF A UPPER-LEVEL RIDGE. THIS
WILL LEAD TO INCREASING CLOUDS THROUGH THE DAY WITH LIGHT
PRECIPITATION REACHING THE CASCADES BY THE AFTERNOON AND
EXPANDING INTO NORTH IDAHO SUNDAY EVENING. THIS WILL MAINLY FALL
IN THE FORM OF LIGHT SNOW GIVEN A COOL, DRY AIR MASS NOW IN
PLACE. AMOUNTS WILL BE EXTREMELY LIGHT WITH MINIMAL IMPACTS. NO
ACCUMULATIONS ARE EXPECTED FROM SPOKANE TO THE PALOUSE WESTWARD
TO WENATCHEE AND OMAK. GREATEST RISK FOR AN INCH OF SNOW WILL BE
OVER THE CASCADE CREST, SELKIRKS, AND BITTEROOTS (60-80%
CHANCE). THERE IS A 10-30% CHANCE FOR HALF AN INCH OR MORE IN
THE VALLEYS OF NE WA AND N ID INCLUDING SANDPOINT, BONNERS
FERRY, AND COLVILLE.
MONDAY-FRIDAY: THERE IS STRONG AGREEMENT AMONGST THE ENSEMBLE
CLUSTERS OF AN ABNORMALLY STRONG UPPER-LEVEL RIDGE SETTING UP
OVER THE WESTERN US THROUGH THIS PERIOD. THE RIDGE AXIS SHIFTS
INLAND MONDAY AND TUESDAY AND STALLS AROUND THE GREAT BASIN FOR
WEDNESDAY THROUGH FRIDAY. MEANWHILE, AN ATMOSPHERIC RIVER RUNS
UP THE WESTERN FLANK OF THE RIDGE. INITIALLY, THE MAIN AXIS OF
MOISTURE WILL BE DEFLECTED INTO SOUTHWESTERN BC WHILE CLIPPING
THE FAR NORTH CASCADES. WITH TIME, THERE IS INCREASING CONCERN
THAT THE RIDGE WILL FLATTEN AND ALLOW THE AXIS OF SUBTROPICAL
MOISTURE SAG SOUTHWARD PLOWING INTO THE NORTHERN AND CENTRAL
CASCADES AND IDAHO PANHANDLE. THIS HAS POTENTIAL TO DELIVER
COPIOUS AMOUNTS OF MOISTURE, MAINLY IN THE FORM OF RAIN, FOR
THE CASCADE CREST AND MODERATE AMOUNTS FOR THE IDAHO PANHANDLE.
STRONG WESTERLY FLOW WILL RESULT IN A BROAD RAIN SHADOW FROM THE
LEE OF THE CASCADES INTO EASTERN WA. SNOW LEVELS START OFF
5000-8000 FEET MONDAY THEN AVERAGE AROUND 7000-9000 FEET THROUGH
MUCH OF THE WEEK. THE WARM AND WET CONDITIONS IS VERY
CONCERNING GIVEN THE POTENTIAL HYDROLOGY IMPACTS, PARTICULARLY
THE CASCADES BUT ALSO TO A LESSER DEGREE, IDAHO PANHANDLE.
HERE ARE THE LATEST PROBABILITIES FOR STORM TOTAL QPF AMOUNTS
FROM SUNDAY-FRIDAY (SOME OF THIS WILL BE SNOW SUNDAY-MONDAY)
TOTAL QPF (SUN-FRI) >1 INCH >2 INCHES >3 INCHES > 5 INCHES
CASCADE CREST100%90%80%40%
IDAHO PANHANDLE 40%10%0%0%
UNCERTAINTY REVOLVES AROUND THE SOUTHWARD EXTENT OF THE
ATMOSPHERIC RIVER INTO THE CASCADE CREST, DOES THIS MAINLY
IMPACT NORTHERN CHELAN/OKANOGAN COUNTY OR SAG SOUTHWARD INTO ALL
OF CHELAN AND NORTHERN KITTITAS COUNTIES? THIS IS SOMETHING
THAT WE WILL BE CLOSELY MONITORING. ADDITIONALLY, HEAVY SNOW
THAT FELL OVER THE LAST 3-5 FAYS WILL BE ABLE TO ABSORB THE RAIN
BUT EVENTUALLY, THE SNOWPACK WILL RIPEN AND CONVERT TO RUNOFF,
ESPECIALLY WITH THE MILD TEMPERATURES AND INCREASING WIND WHICH
CAN BE A SNOW EATER. WE ARE NOT ANTICIPATING STRONG WINDS BUT
CONSISTENT BREEZINESS WITH GUSTS 20-30 MPH, ESPECIALLY OVER THE
HIGHER TERRAIN.
TEMPERATURES WILL BECOME QUITE MILD FOR MID MARCH STANDARDS.
850MB TEMPERATURES WILL BE 2-3 STANDARD DEVIATIONS FROM NORMAL
OR IN THE 90-99TH PERCENTILES. THIS WILL EQUATE TO LOWLAND
TEMPERATURES INTO THE 50S-60S TUESDAY THEN 60S-70S BY THE END OF
THE WEEK.
SATURDAY-SUNDAY: ROUGHLY 60% OF THE ENSEMBLES FLATTEN THE RIDGE
AND INTRODUCE A SHORTWAVE INTO THE REGION. THE REMAINING 40%
MAINTAIN A FLAT RIDGE. LARGE DIFFERENCES IN TIMING OF THIS
OCCURRING VARYING FROM SATURDAY TO MONDAY. WHEN THIS OCCURS,
TEMPERATURES WILL COOL AND PATTERN RECOGNITION WOULD SUGGEST
INCREASING WINDS. PRECIPITAITON CHANCES WILL ALSO BE ON THE
RISE. MODELS DO SUGGEST TIES TO THE SUBTROPICAL MOISTURE WILL BE
CUTOFF BY THIS PERIOD SO WHETHER THE RIDGE HOLDS OR DEFLATES,
THE THREAT FOR HEAVY PRECIPITAITON WILL BE DECREASING THOUGH
MOUNTAIN SNOW MELT WILL LIKELY CONTINUE AT LEAST EARLY IN THE
PERIOD CONTRIBUTING TO RUNOFF UNTIL THE COOLER AIR CAN BECOME
ESTABLISHED. /SB
AVIATION
06Z TAFS: VFR SKIES EXPECTED OVER THE INLAND NW. PATCHY SHALLOW
FOG POSSIBLE IN THE MORNING (5-10% CHANCE) WITH THE HIGHEST
PROBABILITIES IN THE VALLEYS OF NE WA AND N ID. OTHERWISE, MID
AND HIGH CLOUDS WILL INCREASE FROM WEST TO EAST WITH APPROACHING
WARM FRONT WITH LIGHT SNOW CHANCES (20-40%) 00-06Z. MODERATE TO
HIGH CONFIDENCE FOR SNOW TO HAVE MINIMAL IMPACTS.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: MODERATE TO HIGH
CONFIDENCE VFR CONDITIONS OVERNIGHT. SURFACE DEWPOINTS ARE LOW
WHICH LEADS TO VERY CONFIDENCE FOR FOG. SNOW DEVELOPING WITH THE
WARM FRONT WILL FALL INTO ABOVE FREEZING AIR INITIALLY SUNDAY
EVENING LEADING TO LOW THREATS FOR ACCUM AWAY FROM THE CASCADE
CREST AND MOUNTAINS OF NE WA AND NORTH IDAHO PANHANDLE. NBM
GIVES KCOE HAS A 30% CHANCE FOR 0.1" BUT HREF HAS 0% CHANCE. /SB
-----------------------
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 41 32 48 42 58 46 / 10 50 40 20 20 40
COEUR D'ALENE 40 32 46 40 54 43 / 10 70 80 40 40 70
PULLMAN 42 35 51 44 59 47 / 10 50 70 30 40 40
LEWISTON 47 40 56 44 64 48 / 0 40 40 20 20 30
COLVILLE 42 29 48 36 59 43 / 10 70 60 20 20 40
SANDPOINT 37 30 42 39 51 41 / 10 70 90 60 50 80
KELLOGG 39 32 46 44 51 45 / 10 80 100 70 60 80
MOSES LAKE 47 34 61 44 68 48 / 10 20 0 10 10 10
WENATCHEE 44 34 58 43 65 47 / 10 40 30 10 30 30
OMAK 42 33 53 39 63 44 / 10 40 20 10 20 20
OTX WATCHES/WARNINGS/ADVISORIES
WA...NONE.
ID...NONE.
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