textproduct: Pendleton

DISCUSSION

Satellite shows the stratus encompassing the lower elevations of the PDT region continuing through today and more than likely (70-80 percent chance) to persist until Monday. As we continue to be dominated by high pressure in the synoptic scale, we'll continue to see freezing fog formation across the lower valleys (especially in sheltered regions). Currently, there's still an area of dense fog around Cabbage Hill, Poverty Flats, and Deadman Pass with less than a quarter of a mile visibility readings. This will persist through the early to mid afternoon hours, but we'll likely (70-90 percent chance) see another formation of freezing fog develop in areas below 2500-3000 feet overnight. Another (Freezing) Dense Fog Advisory is likely tonight (60-80 percent chance) for the Foothills of the Blues, Kittitas Valley, Central Oregon, and North Central Oregon. Air Stagnation is another highlight that will continue through 4PM Tuesday, with poor air quality conditions and very light winds through the lower elevations.

We'll get better mixing heading into mid-week with the ridge weakening and a shortwave passing through California, the stratus is probably (50-70 percent chance) going to be eaten up with the subsidence fading away. With that, we'll see our PoP chances go up to 20-40 percent chances heading into Friday and through the weekend as a cold front approaches from Washington and Canada before stalling over the area. Snow levels will be much lower in this period, dropping to around 2000-3000 feet (and as low as 1500 feet in parts of the Washington Columbia Basin). This will be a mainly snow dominated system, with the heaviest areas in the mountain region receiving up to 3 to 5 inches through the weekend (30-50 percent confidence) and parts of the Foothills of the Blue Mountains (and some parts of the Basin close to the Foothills) getting up to a quarter inch of snow (20-40 percent confidence). Of course, this is all through Day 5-7 currently and guidance could change, but the overall tone after the current ridge departs, is that we'll at least see some areas of light to moderate mountain snow (mostly light) and slight chances of a dusting in parts of the Foothills.

AVIATION...00Z TAFS

Conditions continue to range from MVFR to LIFR across the region. There has been some improvement at BDN and RDM, but expect both sites to have ifr/LIFR VSBYS this evening/overnight and into Monday. Overall, don't expect many changes. There could be a few sites that drop from MVFR to IFR CIGS, for example. Winds continue to be very light.

PRELIMINARY POINT TEMPS/POPS

PDT 24 36 23 36 / 0 0 0 0 ALW 26 36 25 35 / 0 0 0 0 PSC 25 38 24 38 / 0 0 0 0 YKM 23 39 23 40 / 0 0 0 0 HRI 25 37 24 37 / 0 0 0 0 ELN 21 36 22 37 / 0 0 0 0 RDM 18 43 20 49 / 0 0 0 0 LGD 22 48 25 45 / 0 0 0 0 GCD 26 53 27 51 / 0 0 0 0 DLS 27 41 26 40 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

OR...Air Stagnation Advisory until 4 PM PST Tuesday for ORZ041-044- 507-508-510-511.

WA...Air Stagnation Advisory until 4 PM PST Tuesday for WAZ024- 026>029-521.