textproduct: Pendleton

KEY MESSAGES

- Low chances (5-15%) of isolated thunderstorm development today through Saturday in the mountain regions.

- Cooler temperatures and breezier winds develop through the weekend with highs dropping down to the mid to upper 70s.

- Another weather system with medium confidence (40-70% chance) that it will bring a wet pattern across the region.

DISCUSSION

Satellite and radar advertise dry conditions across the board, with some cumulus clouds forming across the Northern Blues to Eastern Mountains. With the influence of a shortwave, a few dry thunderstorms may develop through the rest of the afternoon. Not expecting widespread coverage with MUCAPE values of >100 J/kg secluded just near the Wallowa's. Tomorrow, the pattern looks about the same with the approaching closed off low located just offshore of British Columbia dropping further south/southeast. HREF paintballs has chances of storms developing in the late morning to afternoon hours near the Eastern Mountains and parts of the Northern Blues. With PWATs fairly low, most of these storms will be dry.

As the system approaches to the area, breezy winds will develop across the region with gusts topping at 25-35 knots (50-70% confidence) with areas of below freezing temperatures in cold prone areas during the overnight hours going into Sunday. Other parts of the Basin will see lows dropping into the low to mid 40s with confidence being medium to high (70-90%) thanks to skies clearing out and winds lighting up through the overnight hours.

Guidance is in agreement that the present low pressure situated over the Pacific just off of BC will continue to move further south and possibly bring a change in the weather pattern. Overall, clusters are struggling with the system past Wednesday, with differences in timing, location, and strength. Of the clusters, 45% predict the trough axis will move on-shore (or close to) by Wednesday afternoon, bringing widespread QPF's across the board. Guidance also shows in the same time period that 30% of members want to considerably weaken the low pressure system, bringing precipitation to just that of the Eastern Mountains. Will need to monitor over the next couple of days to see if guidance can come to an agreement on the low pressure system and how much PoP's evolve as well.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

VFR conditions will persist through the forecast period. Winds remain breezy at DLS/PDT/RDM/BDN while ALW/PSC/YKM remain below 10 kts. ALW/PSC/YKM will see an increase in winds after 09Z for ALW and 17Z for PSC/YKM. Smoke has stayed aloft and there is low confidence it will reach the surface and affect any VIS through the period.

Preliminary Point Temps/PoPs

PDT 47 73 42 77 / 0 0 0 0 ALW 54 74 48 77 / 0 0 0 0 PSC 52 78 46 80 / 0 0 0 0 YKM 54 76 48 81 / 0 0 0 0 HRI 54 76 47 80 / 0 0 0 0 ELN 48 69 43 75 / 0 0 0 0 RDM 40 73 34 79 / 0 0 0 0 LGD 48 75 40 79 / 0 0 0 0 GCD 50 77 41 80 / 0 0 0 0 DLS 57 75 51 80 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...None. OR...Air Quality Alert until noon PDT Monday for ORZ041-505-506- 509>511.