textproduct: Pendleton

DISCUSSION

Satellite shows the stratus is continuing to dominate the region with low ceilings of less than 1000 feet. A passing shortwave has not done much of clearing out the stratus deck, so am confident (70-90 percent chance) that the stratus will stay through today and through tonight. Periods of freezing fog will occur in the lower elevations, especially in some sheltered valleys. Currently have a freezing fog advisory for North Central Oregon with stratus completely obscuring parts of US-97 and US-197 that will likely (60-80 percent chance) be extending past it's 5 PM cut off. There have been observations of very light freezing drizzle and other wintry precipitation across areas near foothills with orographic lifting allowing some precipitation process to occur. Accumulation is not looking to be significant during these phases and is difficult to pinpoint these events on radar given the very light nature. Otherwise, parts of Central Oregon in the Bend shifted winds from the NW, which will not help with the fog in the area. Closer to Pendleton, roads near Cabbage Hill and Deadman Pass have observed visibilities of less than a quarter of a mile.

Poor air quality in southern Deschutes county has been extended through 10 AM Thursday due to the temperature inversion trapping pollutants that includes Three Rivers and La Pine. Otherwise, weather remains mostly benign with mostly calm to light winds across the area. The Air Stagnation Advisory will be discontinued at 4 PM this afternoon (Tuesday) with mixing heights increasing 1500 to 2500 feet through the week. Our next chances of precip will be early next week with mountain snow returning with a dusting to an inch as of now.

AVIATION...00Z TAFs

Widespread low stratus (MVFR or lower), with areas of FZFG, are forecast through the period across the region. After a brief reprieve from the fog and stratus at BDN/RDM earlier this morning, a surge of north to northwest winds brought FZFG and LIFR stratus back to both sites by mid-morning. While there is potential for entrainment of drier air to erode the stratus deck in places, confidence in this scenario is too low (<20%) to show a removal of low CIGs Wednesday. In fact, 12Z and 18Z CAMs suggest a better chance for a return, or persistence, of FZFG overnight into Wednesday morning, with the highest confidence (70-90%) at RDM/BDN and medium confidence (40-60%) at PDT/ALW.

Winds of 10 kts or less are forecast for all sites the remainder of the period.

PRELIMINARY POINT TEMPS/POPS

PDT 26 32 21 33 / 0 0 0 0 ALW 28 32 24 34 / 0 0 0 0 PSC 31 35 23 36 / 0 0 0 0 YKM 27 35 22 36 / 0 0 0 0 HRI 31 33 23 35 / 0 0 0 0 ELN 26 33 20 33 / 0 0 0 0 RDM 23 39 17 38 / 0 0 0 0 LGD 24 40 21 40 / 0 0 0 0 GCD 21 47 25 45 / 0 0 0 0 DLS 33 37 26 38 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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

Freezing Fog Advisory until 5 PM PST this afternoon for ORZ510.

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