textproduct: Pendleton

KEY MESSAGES

- Chance of showers and isolated thunderstorms this afternoon in the eastern mountains

- Temperatures gradually warming to above normal through the remainder of the week

DISCUSSION

Today and Tuesday: Satellite imagery tonight shows scattered decks of mid to high level cloud cover across portions of southeast WA and northeast OR, with very little shower activity noted on regional radar.

Today, a weak shortwave under a north northwest flow aloft will dive across the inland PacNW, resulting in isolated to scattered shower chances across the eastern mountains this afternoon. A weak thunderstorm or two may develop this afternoon over the eastern mountains as developing showers tap into a weak pool of instability developing into the afternoon (CAPE <500 J/kg and high low level lapse rates). Tuesday, another shortwave will move across the region, but will track across eastern WA into far northeast OR due to upper ridging pushing towards the PacNW. Shower activity will be limited the northern Blues and ridges in Wallowa county in the afternoon.

Wednesday through Friday: Upper level ridging will build over the region through the latter half of the work week (confidence 70-85%). This will result in drying and warming conditions across much of the forecast area. High temperatures will warm well above normal, with mid 70s in the mid elevations (central OR) and upper 70s to lower 80s in the lower elevations.

Saturday and Sunday: Ensemble cluster guidance is in good agreement that a positively tilted upper trough will slide over the PacNW through the weekend, however there is disagreement on the depth and position of the trough as it moves inland. Regardless of the position, ensemble cluster solutions indicate a southwest flow into the inland PacNW, keeping temperatures above normal over the weekend. The upper trough and southwest flow aloft will also promote shower chances over the eastern mountains both Saturday and Sunday afternoons, with a slight chance of isolated thunderstorms developing as well (confidence 30-50%). Lawhorn/82

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

VFR conditions are expected through the TAF period. Winds will generally be 10 kts or less, except at BDN, RDM and DLS where winds will gust in the 20 to 25 kt range this afternoon and into the early evening before subsiding back to 10 kts or less this evening.

Preliminary Point Temps/PoPs

PDT 65 41 66 40 / 20 10 0 0 ALW 66 45 67 44 / 20 10 0 0 PSC 71 43 72 43 / 20 0 0 0 YKM 69 40 70 41 / 10 10 0 0 HRI 69 43 69 41 / 20 0 0 0 ELN 64 40 62 38 / 10 10 0 0 RDM 62 29 64 30 / 0 0 0 0 LGD 59 35 64 40 / 40 10 10 0 GCD 58 32 64 38 / 40 10 10 0 DLS 69 44 66 42 / 0 0 0 0

PDT WATCHES/WARNINGS/ADVISORIES

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