textproduct: Pendleton

KEY MESSAGES

1. Winds continue through the week WIND ADVISORY IN EFFECT THROUGH 9 PM SUNDAY

2. Moderate to heavy snow Monday into Tuesday WINTER WEATHER ADVISORY IN EFFECT 5 AM MONDAY THROUGH 5 PM TUESDAY 3. Heavy snow Tuesday night into Friday morning WINTER STORM WATCH IN EFFECT LATE TUESDAY NIGHT THROUGH FRIDAY MORNING

DISCUSSION

Current satellite shows partly cloudy skies with areas of dust due to the winds. Blowing dust can cause VIS issues while driving. A WIND ADVISORY is still in effect through 9 PM. Ground observations, especially around the Tri-Cities is showing a max gusts between 45- 52 mph. These winds will continue through the remainder of the day before decreasing to sub advisory overnight (70-90% confidence). Winds will remain breezy through the week with sustained winds between 15 to 20 mph with gusts of 30 to 35 mph through at least Thursday (40-70% confidence).

Models are in firm agreement showing a shortwave system moving into the region tomorrow with a band of precipitation that will bring moderate to heavy mountain snow. A WINTER WEATHER ADVISORY is in effect 5 AM Monday through 5 PM Tuesday for the Upper Slopes of the Eastern Washington Cascades for 8 to 14 inches of snow across Snoqualmie Pass and White Pass (90% confidence). Winds will remain increased through the same period with gusts to 40 mph likely (60- 80% confidence). This will cause some VIS issues through the passes so please plan ahead if traveling through the i-90 and HWY 12 corridors Monday into Tuesday.

Models then show an atmospheric river push in behind bringing in higher precipitation amounts. The CW3E AR landfall tool shows 80-90% probabilities of a 250kg/(ms) AR will making landfall Tuesday night and persisting through Friday morning. Snow levels will be low at around 1500 feet, however, models show the majority of the accumulations will occur above 3000 feet. NBM raw ensembles show there to be an accumulation of between 2 to 4 feet of snow through the period of Tuesday night through Friday morning(60-80% confidence). Due to this, a WINTER STORM WATCH has been issued for late Tuesday night through early Friday morning. 90

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

All sites reporting VFR conditions with 15-25 knot winds, with breezier winds at DLS/PDT/YKM. Winds have decreased since the 00Z TAFs, but will continue to see at least 10-20 knot winds through the rest of the TAF period. Otherwise, expecting mostly dry conditions with wind and wind direction being the main highlight this period.

Preliminary Point Temps/PoPs

PDT 33 46 28 47 / 40 20 30 10 ALW 35 47 30 48 / 50 30 60 20 PSC 35 53 30 53 / 10 10 10 0 YKM 30 48 25 48 / 0 20 10 10 HRI 36 51 30 51 / 10 10 10 0 ELN 29 43 24 42 / 20 30 30 30 RDM 28 44 21 44 / 0 0 0 0 LGD 31 42 25 42 / 60 30 70 30 GCD 33 43 23 41 / 20 20 30 20 DLS 37 49 32 49 / 20 40 30 30

PDT WATCHES/WARNINGS/ADVISORIES

WA...Winter Weather Advisory from 5 AM Monday to 5 PM PDT Tuesday for WAZ522. Winter Storm Watch from late Tuesday night through Friday morning for WAZ522. OR...None.