textproduct: Pendleton

KEY MESSAGES

- Rain chances returning Today and again late Saturday though Saturday night.

- Breezy winds late Saturday through Sunday morning.

- Mountain precipitation persist through early part of week.

DISCUSSION

GOES satellite imagery and METARS are now showing invading mid level cloud cover reaching the Tri Cities to the central Oregon Mts, with mid level cloud bases and generally no precipitation just yet even immediately on the windward side of the Cascades. Some reduced visibility at the Snoqualmie pass/Kittitas valley and Lagrande areas between one half and three quarters of a mile have been observed with no other notable foggy areas developing overnight.

An upper low moving into BC Today will influence the WA Cascades, adjacent valley and perhaps even the Columbia Basin with light rain on and off Today and This evening. For Today, the chances for wetting rain are about 90 percent and higher across the Washington Cascade Eastern Upper Slopes, 50 to 90 percent in the the lower slope and about 50% across the Yakima Valley extending into parts of the Lower Columbia Basin of Washington. Snow levels look to be above about 8000 ft.

A dryer period is expected overnight, through about Saturday afternoon where probabilities for precipitation are near zero, sky becomes partly sunny and temperatures rebound 5 to 10 degrees on average across the Blue Mt foothills, Columbia and John Day Basins, into central Oregon. Saturday will also see the development of more breezy conditions across the eastern mountains the Grande Ronde Valley.

A second more robust system swings though the area with a cold frontal boundary forcing a large area of slab precipitation farther southward into Oregon late Saturday afternoon and through the overnight. The system will extend the period of gusty winds across the eastern Mountains as well as bring higher rainfall amounts over the Cascades.

By Sunday morning up to 1.5-2 of Maximum precipitation on a 48 hour basis is possible with a mean (more probable) of around 1 - 1.25 inches along the Upper slopes of the Washington Cascades and the Crest. Some rain/snow mix will have better potential as well as snow levels drop to below 5,000 ft late Saturday night.

Several more upper lows from the Eastern Pacific are modeled by ensembles to move near or inland, resulting with the NBM creating widespread probability for precipitation Monday, Tuesday and again on Friday, with rain or rain/snow chances sustained across at least the Cascades all week.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

VFR conditions prevail with some showers crossing through the CWA. Will see PROB30 showers at PDT/DLS/YKM/ALW/PSC over the next few hours with slight chances (5-15%) of MVFR conditions temporarily developing during the heaviest showers. Otherwise not expecting considerable CIG and VIS issues.

Preliminary Point Temps/PoPs

PDT 62 40 65 44 / 10 10 0 10 ALW 58 48 66 48 / 10 10 0 10 PSC 58 41 59 40 / 10 30 0 10 YKM 56 41 59 40 / 20 30 0 20 HRI 58 40 61 40 / 10 10 0 10 ELN 53 37 55 34 / 40 60 0 40 RDM 65 35 69 38 / 0 0 0 10 LGD 54 37 59 42 / 0 0 0 0 GCD 61 37 67 39 / 0 0 0 0 DLS 60 45 62 45 / 10 40 0 70

PDT WATCHES/WARNINGS/ADVISORIES

WA...None. OR...None.