textproduct: Pendleton

KEY MESSAGES

1. Continued southwest flow will bring chances of thunderstorms and showers through Monday.

2. Increased Gap winds Monday night and Tuesday

DISCUSSION

Current nighttime satellite shows mid level clouds over a vast majority of the region. Radar shows the last of the cells to be tapering of and not producing any lightning or rainfall with them. The overcast conditions through the night will help to keep overnight low in the low to mid 50s with areas in the Basin seeing low 60s.

Models show southwest flow to remain over the region through Monday. This will allow moisture to continue to move into the region. CAMs models show there to be solid chances of thunderstorms each day through Monday. Models indicate chances (15-25%) for thunderstorms today after 1100 across portions of Union County into the Eagle Caps and even Wallowa Valley. Looking at RAP forecasted soundings, there is more than enough MUCAPE to fire off a few storms across the area. Models show MUCAPE over 700 J/kg, lapse rates between 8-10 C/km, LIs at -4 to -6 and shear nearing 30 kts. This coupled with the orographic lift could lead to a few stronger storms popping up over the area this afternoon. Models show roughly the same set up the next day with continued southwest flow. However, forecast soundings are a bit weaker than previous days with MUCAPE in the 400-700 J/kg range with LIs of -3 to -4 and lapse rates of 7-9 C/km and shear below 25 kts. This is still more than enough to allow thunderstorms to occur, however, confidence in thunderstorms occurring is 10-20%.

By Tuesday models begin to show an upper level low pushing into the region from the north bringing split flow across the region. As that upper level low continues to dig south, gradients along the WA Cascades begin to tighten with the northwest flow aloft. Winds are expected to increase through the Cascade Gaps on Tuesday as the system moves over the Cascades. NBM raw ensembles show winds to be between 20-25 mph with 50-70% confidence. Gusts to 30-45 through the gaps as well.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

VFR conditions will persist through the forecast period. Winds will be generally below 10 kts with some gusty winds at RDM/BDN this afternoon. DLS will remain breezy through the period with sustained winds 12-15 kts and gusts to neat 25 kts. Upper level smoke may linger, but little confidence in surface smoke causing any VIS issues at any of the TAF sites.

FIRE WEATHER

Dry conditions will continue over the area through the week and fire weather concerns will remain elevated. Threat of thunderstorms is 15-25% along the far eastern mountains and into Wallow today and again on Monday. After Monday, the threat of thunderstorms diminish. Daytime humidities will range from 15-25% each day. Winds will increase Tuesday with sustained winds through the Gaps of 20-25 mph and gusts 30-35 mph. With the increased winds on Tuesday, there are some isolated areas that may reach critical conditions, mainly along the southern Blue foothills.

Preliminary Point Temps/PoPs

PDT 88 57 89 60 / 0 0 0 0 ALW 89 63 90 66 / 0 0 0 0 PSC 93 60 93 60 / 0 0 0 0 YKM 91 61 93 63 / 0 0 0 0 HRI 91 61 92 63 / 0 0 0 0 ELN 86 59 89 60 / 0 0 0 0 RDM 87 51 88 49 / 0 0 0 0 LGD 89 57 91 56 / 10 0 10 20 GCD 91 56 91 55 / 0 0 0 0 DLS 89 61 92 63 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Air Quality Alert until noon PDT Monday for WAZ026-522-523. OR...Air Quality Alert until noon PDT Monday for ORZ041-503-505-506- 508>511.