Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
315 FXUS66 KPDT 040542 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 1042 PM PDT Sun Aug 3 2025 Updated Aviation Discussion .AVIATION...06z TAFs...VFR conditions expected through the period. Shower and thunderstorm activity will shift eastward heading into Monday and is largely expected to remain in the eastern mountains, avoiding all TAF sites. Expect SW/W winds overnight tonight generally less than 12 kts, shifting more W/NW during the day tomorrow. Gusts will remain in the 20-30 kt range for DLS. Cigs will be sct-bkn around 10-15 kft. Evans/74 && PREV DISCUSSION... /issued 1247 PM PDT Sun Aug 3 2025/ DISCUSSION...Thunderstorm activity will persist in the region through Monday afternoon, with the next round of precipitation chances developing Wednesday into Thursday. More benign weather conditions will develop across the region starting Wednesday, while locally breezy conditions will develop each afternoon through Thursday in the Cascade Gaps into the Columbia Basin. Today through Monday: Satellite and radar imagery shows convective activity is already starting to kick off across southeast and central OR this afternoon. This activity is associated with a shortwave impulse moving across the region ahead of the shortwave trough located offshore the PacNW. Scattered showers and thunderstorms will continue to develop across central OR to the eastern mountains through this evening, with most thunderstorms capable of producing abundant lightning, gusty outflow winds, small hail, and heavy rainfall. Forecast CAPE of 500-1000 J/kg, effective shear of 25-35 kts, and inverted-v soundings should facilitate a marginal threat of severe (58 mph or greater) outflow winds, while hail will generally remain small and sub severe through this evening(though a strong storm could produce hail near 1 inch). Convective activity will become more isolated overnight with mainly showers persisting across the eastern mountains. Shower and isolated thunderstorm activity will push to far northeast OR and southeast WA Monday as the shortwave trough swings inland. Most of the storm activity will continue to be focused ahead of the shortwave trough axis, and will lift out of the region by Monday evening as the shortwave exits into ID. Tuesday through Thursday: Dry conditions will develop Tuesday as broad troughing begins to build across the PacNW and northeast Pacific. Ensemble cluster guidance is in good agreement that by Wednesday the axis of the broad trough will move inland while a surface cold front pushes across western WA and northwest OR. Shower activity will develop along the Cascade crest by Wednesday afternoon, with shower chances (15-30%) expanding to the Blue Mountains Wednesday night through Thursday (confidence 60-80%). During this period, temperatures will also cool to below seasonal normals, with mainly 80s across the region. Friday through next weekend: great agreement amongst ensemble cluster members that upper level ridging will develop over the northeast Pacific, with the ridge axis nudging closer to the PacNW through Sunday. This will leave the region under dry conditions with a slight warming trend back into the 90s across the lower elevations (confidence 50-70%). Lawhorn/82 && .PRELIMINARY POINT TEMPS/POPS... PDT 58 82 56 86 / 20 20 0 0 ALW 63 82 60 86 / 20 30 10 0 PSC 59 86 57 88 / 10 20 0 0 YKM 60 86 58 88 / 10 0 0 0 HRI 61 85 58 88 / 20 20 0 0 ELN 58 80 57 84 / 0 0 0 0 RDM 49 80 47 84 / 30 10 0 0 LGD 55 79 51 86 / 50 40 10 0 GCD 53 79 51 85 / 60 30 10 0 DLS 60 79 59 85 / 10 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...82 LONG TERM....82 AVIATION...74