Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
543 FXUS66 KPDT 052027 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 127 PM PDT Thu Jun 5 2025 .SHORT TERM...Today through Saturday...Another quiet day is upon us as dry northerly flow prevails over the PacNW, leading to mostly clear skies and seasonable temperatures. A building high pressure system over the north Pacific will lead to an amplified NW flow pattern that in turn will make for gusty conditions through the Cascade Gaps during the day Friday. Guidance suggests gusts through the Columbia River Gorge and Kittitas Valley could eclipse 30 mph. As this high pressure system moves onshore, attention will shift toward that of our first heat wave of the summer. Not much else to speak of weather-wise until the heat really starts to build in on Sunday. Temps will be noticeably warmer on Saturday with highs in the lowlands reaching well into the 90s, but we will see some overnight relief, as we`re early enough in the warm season that low temps are expected to bottom out into the 50s and low 60s, lessening the severity of this upcoming heat spell. Evans/74 .LONG TERM...Sunday through Thursday...Sunday and Monday continue to be the warmest days of the period according to guidance as strong high pressure persists over the region. NBM has nudged temps upward a degree or two on Monday, with widespread highs above 100 across the lower Basin, potentially spreading into the Yakima and Walla Walla Valleys as well. NBM probabilistic currently suggests about a 50-70% chance for highs to exceed 100 degrees on Monday for the lower Basin, and 40-50% for the other areas mentioned. Elsewhere across the lowlands, highs look to easily reach the mid to upper 90s. A bit too early for headlines on this brief heat wave for now, but it`s looking increasingly likely that Heat Advisories will be needed Sunday and Monday, especially given the fact that it`s only early June. Both the deterministic GFS and ECMWF depict ridge breakdown occurring during the latter half of Monday, with a pair of weak shortwaves circulating through the region Tuesday into Wednesday. This pattern is prime for dry thunderstorms across our eastern mountains, so did make sure to include mention of it in the forecast for at least Monday and Tuesday afternoon (PoPs 15-20%), which the NBM does seem to pick up on in some isolated spots this far out, further increasing confidence. Fuels at the higher elevations are not quite at critical levels, but isolated storms spilling out into the nearby foothills could potentially lead to critical conditions, depending on whether or not such zones are declared ready for wildfire season. Will be something to keep an eye on in the coming days. Afterwards, Wednesday onward, ensemble clustering broadly suggests a cool, troughing pattern, reversing the heat expected this weekend. The overall synoptic pattern is progressive enough to hinder confidence (only around 40% at this time), but models do suggest cooler temperatures by the end of next week, with lowland highs closer to low 80s and even 70s. Evans/74 && .AVIATION...18z TAFs (Previous Discussion)...VFR conditions expected. Clear skies and light northerly winds will prevail at most sites, except for DLS, BDN, RDM which will see locally breezy winds at times this afternoon with gusts up to 20 kts. High clouds are then expected to build in overnight tonight. Evans/74 && .PRELIMINARY POINT TEMPS/POPS... PDT 85 55 90 58 / 0 0 0 0 ALW 84 59 88 62 / 0 0 0 0 PSC 88 56 93 59 / 0 0 0 0 YKM 87 59 92 59 / 0 0 0 0 HRI 88 55 93 59 / 0 0 0 0 ELN 86 58 87 58 / 0 0 0 0 RDM 81 45 86 49 / 0 0 0 0 LGD 79 50 83 54 / 0 0 0 0 GCD 80 48 85 53 / 0 0 0 0 DLS 87 61 90 60 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...74 LONG TERM....74 AVIATION...74