textproduct: Pendleton

DISCUSSION

Key Messages...

1. Rain, mainly in the Cascades through Tuesday.

2. Breezy to Windy through tonight.

3. Very Windy Wednesday with significant snow over Cascades and lower snow levels through the end of the week.

4. River flooding returns to some areas of the Yakima and Naches Rivers from Wednesday through the end of the week.

Rain will continue mainly across the mountains through Tuesday. The lower elevations should be generally dry.

The rain will cause runoff, which will begin around Wednesday at some points on the Yakima and Naches. River Flood Watches have been issued. Rivers are expected to remain high into next week, though they will slowly recede. With less rain and lower snow levels expected, while rivers will rise, they are not expected to reach the levels they reached last week.

As this first system moves through, breezy to windy conditions are expected through tonight and wind advisories remain in effect.

Then the next system, a trough, potent short wave and strong cold front will move across the region later Tuesday into Wednesday. These features will bring very strong winds, snow to the mountains and lowering snow levels. Behind the cold front, there will be about a 10 degree drop in temperatures, though temperatures will still be above normal.

Winds will increase and become quite gusty on Wednesday with gusts in the 40 to 50 mph range area wide and some locations getting as high as 60 mph plus. NBM probabilities of wind gusts >=47 mph are >=90 percent over a large part of our area on Wednesday. Wind gusts >=55 mph are 70 to 90 percent over the Yakima Valley, Simcoe Highlands, Columbia Basin, amd Foothills of the Blue Mountains. High wind Watches remain in effect.

Snow levels, which currently range from 8000 to over 9000 feet, will drop sharply on Wednesday and by Wednesday afternoon, will be between 2000 to 2500 feet. Snow amounts look to be in the 6 to 10 inch range at Snoqualmie and White Passes.

Precipitation will linger over the weekend in the mountains, but amounts will be lighter, while over the lower elevations it will be mainly dry.

AVIATION

Aside from temporary sub-VFR conditions within rain showers this afternoon and evening, predominantly VFR conditions are anticipated for the next 24 hours. Breezy winds of 10-20 kts with gusts of 25-35 kts are forecast through much of the period. Did include mention of low-level wind shear at YKM/PSC where winds aloft are strongest (45-55 kts at 2kft AGL).

PRELIMINARY POINT TEMPS/POPS

PDT 43 61 40 50 / 40 10 90 50 ALW 46 60 42 51 / 60 30 100 70 PSC 43 60 42 54 / 20 20 90 30 YKM 37 58 38 50 / 10 50 100 30 HRI 43 61 42 53 / 30 10 90 40 ELN 34 50 33 44 / 30 70 100 50 RDM 37 58 33 45 / 30 10 100 50 LGD 40 55 36 48 / 60 20 90 80 GCD 43 56 36 49 / 40 10 90 80 DLS 45 59 43 51 / 50 60 100 70

PDT WATCHES/WARNINGS/ADVISORIES

OR...High Wind Watch from Tuesday evening through Wednesday afternoon for ORZ041-044-507-508-510-511.

Wind Advisory until 10 PM PST this evening for ORZ507-508.

WA...High Wind Watch from Tuesday evening through Wednesday afternoon for WAZ024-026>029-521.

Wind Advisory until 10 PM PST this evening for WAZ026>028.

Flood Watch through Wednesday morning for WAZ522-523.

Winter Weather Advisory from 4 PM Tuesday to 10 PM PST Wednesday for WAZ522.