Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
969 FXUS66 KPDT 100600 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 1100 PM PDT Wed Jul 9 2025 .EVENING UPDATE...Red Flag Warnings have been cancelled. For the warning that was in effect for ORZ691/WAZ691 (Lower Columbia Basin of Oregon and Washington), relative humidity values have risen well above critical thresholds. Breezy to windy conditions will persist through the evening. For the warning that was in effect for ORZ698 (Southern Blue Mountains), the threat of abundant cloud-to-ground lightning has ended. Plunkett/86 && .AVIATION...06Z TAFs...VFR conditions are forecast for all sites through the valid period. Clouds will consist mainly of FEW-SCT stratocumulus or cumulus with otherwise SKC. Periods of breezy to locally windy conditions will persist for all sites through Thursday. Strongest winds will be at DLS/PDT. Plunkett/86 && .PREV DISCUSSION... /issued 155 PM PDT Wed Jul 9 2025/ .SHORT TERM...Tonight through Friday...Satellite imagery this afternoon shows a cold front passing over western WA and northwestern OR, while small cumulus fields are starting to develop along the higher terrain of the eastern mountains. Today, an upper trough with an attendant cold front will continue to sweep across the PacNW and exit the region by tonight. Convective activity will pick up ahead of the trough axis through this afternoon, with any developing storms tapping into modest surface instability and low level lapse rates, allowing for isolated thunderstorms to develop mainly across the higher terrain of Grant, southern Union, and Wallowa counties. The best chances are going to be just south of Grant County, where a Red Flag Warning is in effect through this evening. In the lower elevations and through the Cascade Gaps, the approach and subsequent passage of the cold front will result in breezy to locally gusty conditions developing this afternoon and evening. The strongest winds (20-30 mph with gusts up to 45 mph) will develop through the Cascade gaps and persist into this evening. The Columbia Basin will also see winds around 20-25 mph with gusts up to 40 mph, with a Red Flag Warning in effect through this evening as winds are strong enough to overcome the impacts from relatively higher RHs this afternoon. Tomorrow, the upper trough will be well east of the region, with a weak northwest flow aloft. Conditions will remain cool but dry across the forecast area with breezy conditions through the Cascade gaps. Thursday evening through Friday, transient ridging will slide into the PacNW, with a warming and drying trend that will last into into early next week. Lawhorn/82 && .LONG TERM...Saturday through Wednesday...Behind the exit of a transient ridge early Saturday, broad upper ridging will develop over the northeast Pacific and extend into the PacNW. Ensemble cluster solutions are in great agreement of this upper ridge sticking around the area through the middle of next week, though agreement decreases Tuesday into Wednesday as to where the ridge axis will be positioned. Otherwise, the only other feature to note will be a shortwave trough attempting to ride over the upper ridge Sunday, which could bring increased breezy conditions through the Cascade gaps. Overall confidence is mod-high (65-80%) that dry conditions will prevail through the extended forecast with a warming trend into the weekend. Locally breezy winds will develop in the afternoons (confidence 60-80%), with strongest winds on Sunday with the upper trough passage (confidence 50-70%). Confidence wanes into the middle of next week with the forecasted temperatures (confidence 30-60%) owing to disagreement on the position of the ridge axis. Lawhorn/82 && .PRELIMINARY POINT TEMPS/POPS... PDT 60 88 58 92 / 0 0 0 0 ALW 64 88 62 92 / 0 0 0 0 PSC 61 91 59 94 / 10 0 0 0 YKM 59 88 59 93 / 10 0 0 0 HRI 62 91 59 95 / 0 0 0 0 ELN 59 82 57 92 / 10 0 0 0 RDM 50 86 48 88 / 0 0 0 0 LGD 57 83 56 87 / 10 0 0 0 GCD 54 86 52 88 / 20 0 0 0 DLS 62 84 61 94 / 10 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ EVENING UPDATE...86 SHORT TERM...82 LONG TERM....82 AVIATION...86