105
FXUS66 KOTX 221200
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
400 AM PST SAT FEB 22 2025
SYNOPSIS
WARMER TEMPERATURES AND RAIN WILL ARRIVE THIS WEEKEND AS HIGH
TEMPERATURES WARM INTO THE 40S AND LOW 50S. RUNOFF FROM RAIN AND
MELTING SNOW WILL LEAD TO INCREASED FLOW AND MINOR FLOODING ACROSS
SOUTHEAST WASHINGTON AND THE CENTRAL AND SOUTHERN IDAHO PANHANDLE.
ANOTHER WEATHER SYSTEM MONDAY INTO TUESDAY WILL BRING MORE RAIN
AND STRONGER WINDS.
DISCUSSION
SATURDAY AND SUNDAY: THE FIRST FRONT OF SEVERAL TO IMPACT THE
PACIFIC NORTHWEST BETWEEN NOW AND TUESDAY IS MOVING THROUGH EARLY
SATURDAY MORNING. LIGHT RAIN DUE TO WARM AIR ADVECTION FROM THE
SOUTHWEST WILL CONTINUE TO MOVE EAST ACROSS WASHINGTON AND NORTH
IDAHO THROUGH THE EARLY MORNING.
FOCUS SHIFTS TO SATURDAY EVENING THROUGH EARLY MONDAY AS TWO SYSTEMS
ACCOMPANIED BY A MODERATE TO STRONG ATMOSPHERIC RIVER IMPACT THE
REGION. MODELS CONTINUE TO BE IN GOOD AGREEMENT WITH THE RIDGE OVER
THE WESTERN US TO PROGRESSIVELY FLATTEN AS THE SYSTEMS RIDE OVERTOP.
THE FIRST SYSTEM WILL ARRIVE SATURDAY AFTERNOON AND EVENING AS A
WARM FRONT LIFTS NORTH ACROSS THE INLAND NORTHWEST. PWATS INCREASING
TO 0.75+ INCHES AS THIS FRONT SPREADS NORTH WILL SUPPORT WIDESPREAD
RAINFALL, ESPECIALLY ACROSS THE CASCADES, FAR EASTERN WASHINGTON,
AND THE IDAHO PANHANDLE AS STRONG WESTERLY FLOW ALOFT FAVORS
OROGRAPHIC ENHANCEMENT. THERE STILL REMAIN DIFFERENCES IN THE ONSET
OF PRECIPITATION AND EXACT AMOUNTS.
A SECOND SURGE OF WIDESPREAD PRECIPITATION WILL OCCUR SUNDAY AS A
MORE COMPACT LOW NEARS THE NORTHWEST COAST. THIS WILL KEEP THE MOIST
SOUTHWEST FLOW DIRECTED INTO THE INLAND NORTHWEST THROUGH THE DAY ON
SUNDAY AND INTO EARLY MONDAY. MODELS HAVE COME INTO BETTER AGREEMENT
ON THE STRENGTH OF THE SURFACE LOW, ALTHOUGH THE DETERMINISTIC GFS
REMAINS SLIGHTLY STRONGER AND SLOWER WITH THE TIMING OF THE UPPER
LEVEL SHORTWAVE AND FRONT AS IT MOVES THROUGH THE INLAND NORTHWEST
LATE SUNDAY INTO EARLY MONDAY. THE 48 HOUR PRECIPITATION TOTAL HAS
TRENDED UPWARD WITH TOTALS BETWEEN 0.80 TO 1.40 INCHES FOR THE
LOWLANDS OF FAR EASTERN WASHINGTON AND 1.5 TO 2.5 INCHES OVER THE
MOUNTAINS WHICH LIES NEAR THE 90TH PERCENTILE AMONG THE GLOBAL
ENSEMBLES. ADDITIONALLY, WINDS HAVE INCREASED FOR SUNDAY NIGHT INTO
EARLY MONDAY AS A COLD FRONT MOVES THROUGH THE REGION WITH WIND
GUSTS 30 TO 45 MPH.
IMPACTS: THE COMBINATION OF WARMER TEMPERATURES, RAIN, AND BREEZY
WINDS WILL RESULT IN RAPID SNOWMELT ACROSS THE LOWLANDS. IF THE
CURRENT FORECAST VERIFIES, RISES IN OUR FLASHIER CREEKS AND STREAMS
WILL BE COMMON ACROSS SPOKANE COUNTY AND THROUGH THE WASHINGTON AND
IDAHO PALOUSE. PONDING OF WATER IN URBAN AREAS WITH POOR OR CLOGGED
DRAINAGE AND FIELD FLOODING WILL BE OF CONCERN. IT IS ADVISED TO
TAKE PROPER PRECAUTIONS TO MITIGATE FLOOD IMPACTS.
MONDAY AND TUESDAY: MODELS CONTINUE TO SHOW A DEEPENING SURFACE LOW
TO SLIDE NORTHWARD ALONG THE PACIFIC NORTHWEST COAST ON MONDAY.
MODELS AND THEIR ENSEMBLES HAVE BEEN TRENDING UPWARD WITH THE WIND
FORECAST WITH A 30 TO 40 PERCENT CHANCE FOR WIND GUSTS OVER 40 MPH
FOR SPOKANE AND THE COLUMBIA BASIN AND AND A 70 PERCENT CHANCE FOR
WIND GUSTS OVER 40 MPH FOR PULLMAN. IF THE STRONGER WINDS WERE TO
PAN OUT, SATURATED SOILS MAY EXACERBATE IMPACTS WITH ISOLATED TO
SCATTERED TREE DAMAGE. THIS SYSTEM WOULD ALSO BRING ANOTHER ROUND OF
WIDESPREAD PRECIPITATION MONDAY INTO TUESDAY. SNOW LEVELS LOOK TO
DECREASE WITH A RETURN TO MOUNTAIN PASS SNOW. CURRENTLY, THERE IS A
30% CHANCE FOR STEVENS PASS TO RECEIVE 12 INCHES OF SNOW. /VMT
AVIATION
12Z TAFS: THE HEAVY RAIN SYSTEM IS PASSING THROUGH THE AREA WITH
PRECIPITATION, CEILINGS ARE AT MOST MVFR STATUS. TAF SITES ARE
EXPECTED TO BE VFR/MVFR WITH LOWERED CEILINGS DUE TO
PRECIPITATION. KMWH LOOKS TO GET DOWN TO IFR AT SOME POINT THROUGH
THE EVENING DUE TO LOCALIZED RAINFALL AND LOW STRATUS. A RAIN
BREAK IS EXPECTED LATE MORNING THROUGH EARLY AFTERNOON. A SECOND
ROUND OF RAIN WILL MOVE AROUND 00Z. THERE IS THE POTENTIAL FOR
KGEG- KSFF- KLWS TO SEE WIND SHEAR VALUES OF 30 KNOTS OR MORE AT
2000 FEET SATURDAY EVENING.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: MODERATE
CONFIDENCE IN TIMING AND LOCATION OF UPCOMING PRECIPITATION,
PARTICULARLY WITH THE SECOND WAVE LATER IN THE TAF PERIOD.
MODERATE TO HIGH CONFIDENCE OF MVFR CEILINGS FOR ALL BUT KEAT
THROUGH THE NIGHT. MODERATE TO LOW CONFIDENCE OF WIND SHEAR VALUES
BEING GREATER THAN 30 KNOTS DIFFERENCE AT KGEG-KSFF-KLWS FOR
SATURDAY EVENING. /JDC
-----------------------
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 44 40 50 38 49 38 / 50 100 90 90 50 80
COEUR D'ALENE 44 38 48 36 48 35 / 70 100 100 90 50 90
PULLMAN 42 37 46 37 47 36 / 50 100 100 90 60 90
LEWISTON 48 42 52 41 53 40 / 30 90 100 90 50 80
COLVILLE 42 37 48 32 46 34 / 50 100 80 80 50 90
SANDPOINT 42 39 45 37 45 36 / 90 100 100 90 60 90
KELLOGG 43 40 45 39 47 37 / 90 100 100 100 60 90
MOSES LAKE 49 40 56 36 51 37 / 30 80 70 40 60 40
WENATCHEE 42 39 49 36 45 35 / 50 80 70 50 70 60
OMAK 42 36 46 33 45 34 / 60 90 70 70 50 70
OTX WATCHES/WARNINGS/ADVISORIES
ID...FLOOD WATCH FROM THIS EVENING THROUGH LATE MONDAY NIGHT FOR
CENTRAL PANHANDLE MOUNTAINS-COEUR D'ALENE AREA-IDAHO
PALOUSE-LEWIS AND SOUTHERN NEZ PERCE COUNTIES-LEWISTON AREA-
NORTHERN PANHANDLE.
WA...FLOOD WATCH FROM THIS EVENING THROUGH LATE MONDAY NIGHT FOR
LOWER GARFIELD AND ASOTIN COUNTIES-NORTHEAST BLUE MOUNTAINS-
NORTHEAST MOUNTAINS-SPOKANE AREA-WASHINGTON PALOUSE.
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