textproduct: Pendleton

KEY MESSAGES

- Areas of mountain snow and low valley rain continue through the night.

- Drier pattern, especially in the Columbia Basin, expected in the second half of the week.

- Chances of light mountain snow showers continue through next week, with mostly dry conditions in lower elevations.

DISCUSSION

Satellite and radar continue to advertise the atmospheric river impacting the PacNW region with heavy mountain snow in the Washington Cascades and, to a lower extent, at the Oregon Cascades. Heavier snow bands are coupled with lower visibility, bringing freezing fog conditions across parts of the WA Cascade Crest, thus a Freezing Fog advisory was issued through late morning Monday. We'll continue to see chances of mountain snow showers until they taper down by Wednesday evening. Until then, we'll see an additional 4 to 8 inches around the pass levels and an additional 14 to 20 inches area above 5000 feet (70 to 80 percent chance) for the Washington Cascade Crest region. Given snow fall rates will drop to a half inch to an inch by the late afternoon hours, the Winter Weather Advisory was extended until 1 PM this afternoon.

Going forward, a stationary front will set-up Tuesday until it passes as a cold front by Wednesday, allowing chances for moderate to heavy rain to increase across the Columbia Basin and into Central Oregon. Six-hour QPF amounts advertise anywhere from .15" to upwards of .25", with the heaviest rain expected overnight Monday into Tuesday, with rain rate dropping down in the late afternoon hours. The pattern shifts to a more dry, warmer pattern as the pattern shifts more zonal with a weak ridge moving just south of Oregon through the weekend. Drier pattern is expected to continue for the lower elevations as chances of light mountain snow remains through next week.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Areas of rain will continue through the TAF period, bringing periods of low to mid level cloud decks and 3 to 5 mile visibility to all TAF sites except BDN/RDM. BDN and RDM will see breezy to windy winds in the later morning hours that would help keep VIS and CIGS in VFR levels. Otherwise, winds else where will stay below 15 knots for the duration of the 12Z TAFs. Guidance suggests sub-VFR conditions will remain after the later morning hours due to the lingering precipitation.

Preliminary Point Temps/PoPs

PDT 38 47 35 49 / 100 90 70 20 ALW 38 46 36 50 / 90 90 80 30 PSC 38 47 34 54 / 90 80 40 10 YKM 33 43 29 50 / 70 70 40 10 HRI 38 47 35 54 / 90 90 50 10 ELN 30 39 28 45 / 50 60 40 20 RDM 36 53 29 47 / 100 90 40 10 LGD 38 49 34 46 / 100 100 90 40 GCD 39 51 34 44 / 100 100 80 20 DLS 38 47 36 52 / 90 90 60 30

PDT WATCHES/WARNINGS/ADVISORIES

WA...Winter Weather Advisory until 1 PM PST this afternoon for WAZ522. Freezing Fog Advisory until 10 AM PST this morning for WAZ522. OR...None.