textproduct: Pendleton

KEY MESSAGES

- Thunderstorms, mainly across eastern areas today.

- Critical Fire weather concerns from lightning and outflow winds.

- Heat Advisories today, then widespread moderate HeatRisk returns early next week, with high temperatures near or above 100 degrees in the Columbia Basin, Yakima Valleys and surrounding areas.

DISCUSSION

An area of low pressure off the coast will move northward into British Columbia through Saturday morning.

High pressure will then build back into the region through early next week.

Current radar shows lingering showers and thunderstorms moving northward across the region. As the low moves north, it will continue to supply short wave energy, mainly over eastern areas later today, which will be supportive of more thunderstorms. Today should be the last day for shower and thunderstorm activity as high pressure then builds back in.

High temperatures will be hot again today, especially across the Columbia Basin and nearby areas, and HeatRisk is moderate. Probabilities of Major HeatRisk range up to about 40 percent in some locations. HeatRisk does decrease after today for Friday and Saturday, but starts to return on Sunday with widespread moderate returning Sunday (>50 percent) and increasing Monday and Tuesday (>70 percent). By Monday and Tuesday probabilities of Major HeatRisk increase to about 30 to 50 percent across the Columbia Basin, Yakima and Kittitas Valleys.

Also today, there will continue to be critical fire weather concerns from lingering lightning this morning and possibly from thunderstorm in the east this afternoon, but areal coverage will be less.

There will be some gust winds today in portions of the Gorge Basin and Simcoe Highlands with wind gusts as high as 30 to 35 mph. Diurnal wind gusts will continue through Saturday, with gusts in the 25 to 35 mph range.

Thunderstorm chances will also return early next week, mainly over the mountains.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

VFR conditions are expected through the TAF period. Lingering SHRA/TSRA this morning could impact any TAF site except BDN/RDM.

SHRA/TSRA expected to redevelop this afternoon, mainly over eastern areas and the most likely sites they would impact would be PDT and ALW.

Winds could gust as high as 30 kts at DLS and 20 to 25 kts at all other sites except ALW and PSC, excluding any SHRA or TSRA.

FIRE WEATHER

Fire weather concerns continue this morning mainly from lightning as lingering thunderstorms move south to north across the area. Thunderstorms will develop this afternoon, mainly over the eastern mountains, but areal coverage should be less. Gusty winds are expected over portions of the Gorge, Basin and Simcoe Highlands this afternoon, but RH values are expected to be higher due to a marine push, but both the thunderstorm development and RH values will have to be monitored.

Preliminary Point Temps/PoPs

PDT 93 56 89 57 / 20 0 0 0 ALW 98 63 92 64 / 20 10 0 0 PSC 99 61 94 61 / 20 0 0 0 YKM 97 60 94 59 / 40 0 0 0 HRI 95 60 93 61 / 20 0 0 0 ELN 94 56 88 56 / 50 0 0 0 RDM 87 47 89 50 / 0 0 0 0 LGD 98 59 93 58 / 30 20 0 0 GCD 98 55 95 55 / 10 0 0 0 DLS 83 59 88 60 / 20 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...Heat Advisory until 9 PM PDT this evening for WAZ026>029. Red Flag Warning until 10 AM PDT this morning for WAZ690-691- 694-695. OR...Red Flag Warning until 5 AM PDT early this morning for ORZ691. Heat Advisory until 9 PM PDT this evening for ORZ044-049-050- 507.