710
FXUS66 KOTX 201033
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
233 AM PST THU FEB 20 2020
SYNOPSIS
THE REMAINDER OF THE WEEK WILL BE DRY WITH NEAR AVERAGE
TEMPERATURES. WE CAN EXPECT A GOOD DEAL OF SUNSHINE AND RELATIVELY
LIGHT WINDS THROUGH FRIDAY. THE ARRIVAL OF A STORM SYSTEM OVER THE
WEEKEND IS EXPECTED TO BRING INCREASING CHANCES FOR RAIN AND SNOW,
AND GUSTY WINDS SUNDAY NIGHT INTO EARLY MONDAY. SIGNIFICANT SNOW
AMOUNTS ARE POSSIBLE OVER THE PASSES, INCLUDING STEVENS AND
LOOKOUT ESPECIALLY ON SUNDAY INTO EARLY MONDAY. THE WEATHER WILL
THEN DRY INTO THE MIDDLE OF NEXT WEEK.
DISCUSSION
TODAY THROUGH SATURDAY: A LOW WILL DROPPING TO OUR SOUTH AND
PUSHING THROUGH CENTRAL CALIFORNIA. IT WILL HELP SHIFT THE RIDGE
EASTWARD FOR THROUGH FRIDAY AND ALLOW A ZONAL FLOW PATTERN TO SET
IN OVER THE PACIFIC NORTHWEST. MOISTURE WILL BEGIN TO PUMP INTO
THE REGION OVER THE CASCADES AND AN INCREASING IN MID TO UPPER
LEVEL CLOUDS IS EXPECTED STARTING FRIDAY. A WEAK DRY SHORTWAVE
WILL PUSH THROUGH THE REGION. THE CASCADE CREST COULD GET SOME
SPILL OVER MOISTURE FROM WESTERN WA BUT NOT LOT IMPACTS EXPECTED
FROM IT. TEMPERATURES ARE EXPECTED TO BE SIMILAR TO PAST COUPLE OF
DAYS. HIGHS WILL IN THE 40S TO LOW 50S. LOWS WILL BE IN THE 20S
TO LOW 30S. /JDC
SUNDAY AND MONDAY...THIS SHOULD BE THE MOST ACTIVE PORTION OF THE
NEXT 7 DAYS AS THE MODEL GUIDANCE REMAINS CONSISTENT ON BRINGING
IN A RELATIVELY STRONG LOW PRESSURE AREA SOMETIME DURING THIS
PERIOD. THE TREND FOR THIS FEATURE IS ONE OF STRENGTHENING AND
SLOWING PER THE EC ENSEMBLE MEANS AND TO A CERTAIN EXTENT THE GEFS
MEAN. THIS SUGGESTS THE BULK OF THE PRECIPITATION NOW LOOKS LIKE
IT WILL HOLD OFF UNTIL LATE SUNDAY MORNING OR AFTERNOON BEFORE THE
COLD FRONT TRACKS THROUGH DURING THE EVENING. THIS SLOWER TIMING
WILL YIELD SLIGHTLY HIGHER SNOW LEVEL DUE TO DIURNAL WARMING. IT
APPEARS MOST OF WHAT FALLS IN THE VALLEYS WILL FALL AS RAIN EXCEPT
FOR VALLEYS IN THE IMMEDIATE LEE OF THE CASCADES AS WELL AS THOSE
NEAR THE CANADIAN BORDER. EVEN IF SNOW DOES FALL IN THESE
VALLEYS, MILD DAYTIME TEMPERATURES COULD LIMIT THE ACCUMULATIONS,
ESPECIALLY ON THE ROADS. IT SEEMS THE BIGGEST ISSUES WITH THIS
SYSTEM WILL REVOLVE AROUND SNOW OVER THE HIGHER MOUNTAINS AND
PASSES. WE SUSPECT STEVENS PASS WILL BE SUBJECT TO A SIGNIFICANT
AMOUNT OF SNOW...PERHAPS NEARING 10 INCHES OR SLIGHTLY MORE
THROUGH EARLY MONDAY MORNING BEFORE THE DENDRITIC LAYER BEGINS TO
DESICCATE. LOOKOUT PASS WILL ALSO SEE SOME DECENT SNOW AMOUNTS
(4-8 INCHES FOR NOW BUT SUBJECT TO CHANGE) WHICH WILL LIKELY
IMPACT TRAVEL THROUGH MONDAY AFTERNOON.
AFTER THE COLD FRONT MOVES THROUGH SUNDAY NIGHT INTO MONDAY WE
ARE LOOKING AT A STEADY INCREASE IN WINDS AND A GOOD CHANCE OF
UNSTABLE SNOW SHOWERS ASSOCIATED WITH THE UPPER LEVEL TROUGH. AS
FOR THE WINDS, THERE IS FAIRLY GOOD AGREEMENT NOW THAT THE PEAK
WILL OCCUR SUNDAY EVENING AS THE SURFACE LOW PUSHES ACROSS
SOUTHERN BC. 850 MB WINDS ARE IN THE 35-40KT RANGE WHICH WOULD
SUPPORT WIND GUSTS NEARING 40 MPH IF IT OCCURS BEFORE THE
ATMOSPHERE DECOUPLES OVERNIGHT. SNOW ACCUMULATIONS WILL BE HIT OR
MISS OVER THE VALLEYS AND WE DONT ANTICIPATE ANY HEAVY VALLEY
ACCUMULATIONS AT THIS TIME. BY MONDAY NIGHT THE DENDRITIC LAYER
BEGINS TO DRY OUT OVER THE ENTIRE FORECAST AREA, CLEARING THE
SOUTHERN HALF OF THE IDAHO PANHANDLE LAST, RESULTING IN DRY
WEATHER.
FROM TUESDAY THROUGH WEDNESDAY WE ARE LOOKING AT DRY WEATHER
AS THE NEXT UPPER LEVEL RIDGE BUILDS OVER THE INLAND NORTHWEST.
TEMPERATURES DURING THE SUNDAY THROUGH WEDNESDAY TIME PERIOD WILL
LIKELY PEAK ON SUNDAY AHEAD OF THE COLD FRONT WITH VALLEY HIGHS IN
THE 40S TO LOWER 50S. THEY WILL THEN COOL OFF INTO THE UPPER 30S
AND 40S ON MONDAY AND TUESDAY BEFORE WARMING SLIGHTLY THEREAFTER.
FX
AVIATION
06Z TAFS: CLEAR SKIES INTO THURSDAY MORNING. THERE WILL ALSO BE
10-15 KTS OF WINDS FROM THE EAST AND SOUTHEAST ACROSS PULLMAN AND
LEWISTON THROUGH THURSDAY MORNING. BANDS OF HIGH CLOUDS WILL THEN
INCREASE THURSDAY AFTERNOON WITH CEILINGS ABOVE 20KFT. /SVH
PRELIMINARY POINT TEMPS/POPS
SPOKANE 43 22 44 28 44 30 / 0 0 0 0 0 10
COEUR D'ALENE 42 21 44 28 43 30 / 0 0 0 0 0 10
PULLMAN 41 27 45 30 45 33 / 0 0 0 0 0 10
LEWISTON 48 30 50 34 51 37 / 0 0 0 0 0 10
COLVILLE 41 19 42 24 43 27 / 0 0 0 0 0 10
SANDPOINT 39 20 40 24 40 28 / 0 0 0 0 10 20
KELLOGG 41 24 43 28 42 29 / 0 0 0 0 0 20
MOSES LAKE 46 25 46 29 49 31 / 0 0 0 0 0 0
WENATCHEE 42 27 44 31 47 32 / 0 0 0 0 0 10
OMAK 41 23 41 28 43 30 / 0 0 0 0 0 10
OTX WATCHES/WARNINGS/ADVISORIES
ID...NONE.
WA...NONE.
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