Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
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152 FXUS66 KPDT 201038 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 338 AM PDT Sat Jul 20 2024 Updated aviation discussion .SHORT TERM...Today through Monday...Following the passage a weak system over the top of the western USA ridge yesterday the ridge will undergo an amplification northward into western Canada. This amplification will result in warming temperatures across the forecast area today through Sunday before cooling on Monday. High temperatures today and Sunday could set record highs across portions of the forecast area. Heat Advisories and Excessive Heat Warnings continue over most of the forecast area which run through Monday. A weak system off the California coast will move up the coast late Saturday night and Sunday. This will provide enough atmospheric forcing combined with the limited moisture to trigger some isolated thunderstorms over central Oregon Sunday afternoon then spread them northward along the east slopes of the Cascades through the evening before ending. Meanwhile, an upper level low pressure system in the Gulf of Alaska will begin moving towards western Canada over the weekend. The associated upper level trough will begin to push the upper level ridge eastward Sunday before slowly moving inland through the first of the week. The eastward progression will shift the thunderstorm potential to over the eastern mountains Monday afternoon and evening. Again, coverage of storms looks to be isolated as moisture is limited. Temperatures will run around 10 degrees cooler on Monday as this will be the end of the heat wave as temperatures return back to near normal by midweek. .LONG TERM...Tuesday through Saturday... The extended period will be characterized by an upper-level trough moving over the region with cool near normal temperatures and breezy winds, driven by a low over British Columbia area. Dry conditions will persist with low relative humidity in the teens to lower 20s. Temperatures will lower to the 80s and 90s across the forecast area through next week as the trough passes. Locally breezy conditions (15-25 mph) will arrive with occasional wind gusts between 20-30 mph each day through evening along the Cascade Gaps and east slopes of the Cascades. This could pose a threat to any ongoing fires as well. Probability for wind gusts exceeding to 45 mph for Kittitas valley is at 30-60%. Feaster/97 && .AVIATION...12Z TAFS...VFR conditions prevail with clear skies and light winds. No current exceptions on visibility obscuration due to smoke, though will remain monitored. && .FIRE WEATHER...Hot, dry and unstable conditions increase over the weekend. With significant fires occurring in Oregon zones 642 and 644 there is a Red Flag Warning in effect through Sunday. Also expecting some isolated thunderstorms in central Oregon Sunday then moving northward along the east slopes of the Cascades towards Washington. There are concerns for elevated fire threat due to increasing winds late Sunday as the cooler air associated with an the approaching trough beginning to push into the region. This will produce winds of 10-20 mph with RH values in the teens to lower 20s. Winds continue on Monday but RH values will be higher generally in the upper teens and 20s. && .PRELIMINARY POINT TEMPS/POPS... PDT 102 63 103 65 / 0 0 0 10 ALW 105 67 109 67 / 0 0 0 0 PSC 104 66 107 68 / 0 0 0 10 YKM 102 67 105 68 / 0 0 0 10 HRI 105 66 107 69 / 0 0 0 10 ELN 101 65 104 69 / 0 0 0 10 RDM 100 61 98 58 / 0 10 20 20 LGD 101 61 105 64 / 0 0 0 0 GCD 104 65 106 65 / 0 0 10 20 DLS 106 69 97 70 / 0 0 10 20 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Excessive Heat Warning from 11 AM this morning to 10 PM PDT Monday for ORZ041-044-049-050-502-503-505-507-508. Red Flag Warning from 11 AM this morning to 11 PM PDT Sunday for ORZ642-644. Heat Advisory from 11 AM this morning to 8 PM PDT Monday for ORZ506-510-511. WA...Excessive Heat Warning from 11 AM this morning to 10 PM PDT Monday for WAZ024-026>030-521. Heat Advisory from 11 AM this morning to 8 PM PDT Monday for WAZ523. && $$ SHORT TERM...91 LONG TERM....97 AVIATION...97