Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
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354 FXUS66 KPDT 160456 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 956 PM PDT Sat Jun 15 2024 Updated Aviation Discussion .AVIATION...06z TAFs...VFR conditions expected. Winds will continue to die down overnight, leaving all sites with light, terrain-driven winds less than 10 kts. Winds will pick back up again across many sites by late tomorrow morning, with mid-level sct-bkn clouds building in as well. Light isolated showers may develop across the forecast area tomorrow afternoon, however rain is expected to be too light to cause any real aviation impacts, at least at the surface. Evans/74 && .PREV DISCUSSION... /issued 708 PM PDT Sat Jun 15 2024/ EVENING UPDATE...A Freeze Warning is in affect through Wallowa Valley with temperatures expected to be widespread below freezing (70-90% probabilities). Main update to the forecast is to better reflect the region where the isolated showers are still affecting, otherwise no large changes to the forecast. Current radar is showing some lingering showers over the Cascades as well as along the Blues and into Wallow County. Westerly winds are still elevated with localized areas seeing gusts above 40 mph. Winds are expected to decrease overnight to 10-15 mph (80% probabilities) with the exception of the ridgetops. Showers will also begin to dissipate and remain along the far northern portion of the WA Cascades. Bennese/90 PREV DISCUSSION... /issued 219 PM PDT Sat Jun 15 2024/ SHORT TERM...Tonight through Monday... Key Messages: 1) Thunderstorms possible through this evening, primarily across WA Columbia Basin and WA/OR Blue Mountains. 2) Cool temperatures keep us well below normal, including temperatures tonight producing near to locally freezing lows. 3) Another slug of moisture brings a second round of shower chances and high elevation snow Sunday into Monday. A deep upper level low moving inland along the borders of the US and Canada will continue eastwards, with part of the troughing splitting off from the main low and remaining over the PacNW. This secondary system will close off into it`s own low, bringing a second round of moisture across the forecast area Sunday into Monday before fully departing into Tuesday. This progressive pattern will continue to bring a cool and wet weather through the duration of the short term period. For this evening, some scattered showers are seen on radar, with a few thunderstorms noted across portions of Franklin County as well as the Blue Mountains. Mesoanalysis indicates a bullseye of 500 J/kg of CAPE in this region, which combined with orographic enhancement into the Blues should continue to promote a few lightning strikes through this evening. These storms should be weak, with lightning and perhaps locally gusty winds the only expected hazards. Temperatures should then drop overnight, with widespread low 40`s and 30`s for our population centers. Central Oregon even has a risk of nearing freezing, but currently not seeing enough indication in models that we`ll see a widespread freeze justifying a freeze warning. Also of note, models have run cold compared to actual overnight lows by around 2-5 degrees over the past couple of days, leading to low confidence in hitting 32, let alone getting below it. Expectation is that this area will near but not quite reach freezing, but if any location were to reach this threshold, it would be Redmond with a 60% chance according the to NBM. Temperatures will continue to run seasonably below normal by 5 to 10 degrees, with highs Sunday and Monday into the 60`s to mid 70`s. Meanwhile, the aforementioned secondary system will bring another round of precipitation, primarily affecting the Cascades and adjacent valleys, and from Central Oregon up through the Blues and Wallowas. QPF amounts remain unimpressive outside of the mountains, with the NBM showing only around a 15% chance of amounts greater than or equal to a tenth of an inch for locations including Pendleton, Walla Walla, and La Grande. The best moisture as usual should be in the mountains, but less than half an inch is forecast at best for this portion of the short term. This may translate into several inches of snow about 4500 feet, including 1-5 inches for the Wallowas. By late Monday into early Tuesday morning precipitation should be exiting as we begin to see warmth return in the coming week. Goatley/87 LONG TERM...Tuesday through Saturday...Models are in good agreement through the extended period. The departing trough system will leave the region under a northwest flow with some lingering moisture over far NE Oregon and SE Washington that will produce a few showers over the mountains. After that the region will be under a dry westerly flow Wednesday through Friday providing temperatures getting back to 5-10 degrees above normal. Then an upper level low pressure in the Gulf of Alaska will move towards Canada on Sunday which will begin to amplify a ridge over the inland Pacific Northwest and northern Rockies. This will place the forecast area under a SW flow with high temperatures around 10 degrees above normal. This pattern could lead to some convection by late Saturday and into Sunday but for now chances are less than 10%. There will be some lingering locally breezy conditions Tuesday through Friday mainly along the east slopes of the Cascades but overall winds are not much of a concern. && .PRELIMINARY POINT TEMPS/POPS... PDT 40 65 43 67 / 10 10 30 20 ALW 43 69 45 71 / 10 0 30 30 PSC 45 71 48 75 / 20 0 20 10 YKM 38 69 42 72 / 10 20 10 0 HRI 44 71 47 74 / 10 10 20 10 ELN 40 66 44 67 / 10 20 10 0 RDM 33 61 35 63 / 10 10 10 0 LGD 37 62 40 61 / 20 10 40 40 GCD 36 63 38 61 / 10 10 40 30 DLS 46 69 49 69 / 10 10 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Freeze Warning until 9 AM PDT Sunday for ORZ050. WA...None. && $$ SHORT TERM...90 LONG TERM....91 AVIATION...74