textproduct: Pendleton

KEY MESSAGES

- Isolated to scattered thunderstorms will develop mainly across the Cascades this afternoon and evening, then across the Cascades and eastern mountains on Thursday.

- Low pressure off the coast will move southward through this evening, then begin to move northward overnight and on Thursday. Models have come into better agreement that the low will move around the periphery of high pressure into British Columbia.

- A large area high pressure will build into the region with warming temperatures into the weekend and early next week, possibly reaching or exceeding 100 degrees in the Columbia Basin and nearby locations.

DISCUSSION

Southwesterly flow across the area and several short waves moving through it will keep the chance for showers and isolated to scattered thunderstorms, mainly over the mountains through Thursday. Additionally, an area of low pressure off the coast was heading south and east and will provide enhancement to the southwesterly flow. This low will begin to move northward tonight and be in British Columbia Friday morning.

Once the low moves north, the ridge to the east will build in and any precipitation chances will come to an end through the weekend.

Temperatures will begin to warm, with highs in the upper 90s to around 100 degrees (if not higher) as we go into the weekend and early next week across the Columbia Basin, Yakima Valley and portions of the Blue Mountain Foothills. These temperatures would be 15 to 10 degrees above normal. HeatRisk will be solidly Moderate across much of our area, with a 30 to 50 percent chance of Major HeatRisk early next week across the Columbia Basin and Yakima Valleys.

By early next week, additional southwest flow will bring additional shower and thunderstorm chance, mainly to the mountains.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

VFR conditions are expected through the TAF period, with most sites having winds 10 kts or less. BDN and RDM will have wind gusts to around 20 kts this afternoon into the early evening and YKM could have some gusty winds overnight.

Otherwise, there will be some isolated to scattered TSRA during the afternoon hours, that should not impact most of the TAF sites. However, if a TAF site were to be affected, BDN and RDM look to be the ones. Therefore, have included PROB30 for TSRA this afternoon at those two locations.

Preliminary Point Temps/PoPs

PDT 97 61 92 56 / 10 20 10 10 ALW 100 67 97 63 / 0 10 10 10 PSC 101 66 98 61 / 10 20 20 10 YKM 99 67 96 60 / 0 60 20 10 HRI 100 66 95 60 / 10 20 20 0 ELN 96 64 93 56 / 0 60 30 10 RDM 91 55 86 47 / 40 30 10 0 LGD 96 61 97 58 / 0 10 20 20 GCD 94 58 97 55 / 20 20 10 0 DLS 98 64 84 59 / 0 70 20 0

PDT WATCHES/WARNINGS/ADVISORIES

WA...None. OR...None.