Area Forecast Discussion
Issued by NWS Pendleton, OR
Issued by NWS Pendleton, OR
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886 FXUS66 KPDT 231536 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 836 AM PDT Mon Sep 23 2024 .MORNING UPDATE...Slight update to the forecast this morning with regards to the smoke and haze lingering over Bend and Redmond. Smoke through Bend has brought visibility to 300 ft above ground while not necessarily impacting the ground. Smoke and haze will linger through the day with northwest winds continually wafting smoke over the area. Bennese/90 && .PREV DISCUSSION... /issued 355 AM PDT Mon Sep 23 2024/ Aviation...12Z TAFS...VFR conditions will continue prevailing through the period. Mid to high (FEW-BKN at 090-250) clouds will prevail for the next 24 hours. Winds will also be light, less than 12kts. Feaster/97 PREV DISCUSSION... /issued 219 AM PDT Mon Sep 23 2024/ SHORT TERM...Today through Wednesday...The short term will see a couple of overall calm and warm days as we heat to well above normal temperatures with an incoming deep trough then beginning a cooling trend that will extend into the long term, along with gusty winds that will flirt with both advisory level criteria and critical fire behavior conditions, along with a chance at most of the region to see a small amount of rain. A ridge of high pressure will be traversing across the Western US, ending up centered across the Four Corners region by Wednesday morning. This ridge will bring increasing warmth, which will be the main weather feature of note today and tomorrow. High temperatures today will range in the upper 70`s to mid 80`s for our population centers, with highs tomorrow around 5 to 10 degrees warmer. Ensembles continue to come into better and better agreement on tomorrow`s unseasonable warmth, with much of CWA now in the mid 80`s to low 90`s for highs. Currently, central and north-central Oregon, the John Day valley, and the foothills of the Blue Mountains look to be the warmest locations, with the NBM producing a 50-90% probability of highs 90+. Into Wednesday, a deep upper level low in the Gulf of Alaska will swing a long wave trough into the Pacific Northwest alongside a cold front, ending the warming trend and producing areas of showers and gusty winds. For temperatures and precipitation - the front will swing across through the course of the day, but afternoon warming should still allow for highs in the 80`s for most of our population centers, warmest in the Columbia Basin as the front doesn`t move across until the mid to later part of the afternoon for the eastern part of our CWA. The NBM is gaining confidence in precipitation as well, with all but the southern portions of Grant and Crook county expecting at least a 20-30% chance of precipitation. Outside of the Cascades, this translates to a 10-40% probability of 0.1 inch or more of QPF - nothing exciting but noteworthy enough for how dry we`ve been of late. As for winds, a 700 mb jet streak of 50-60 knots will move across with the system. These winds should have a good chance of mixing down with the front, and the NBM indicates 24-hour max wind gusts of 45+ mph have a 30-80% probability for the Columbia Gorge, lower Columbia Basin of Oregon, Simcoe Highlands, and Kittitas Valley. The previous forecast was used as a base and blended in the NBM 90th percentile, giving widespread gusts of 30-40 knots - just barely outside of wind advisory levels, but barely. For our fire weather partners, this does bring near critical fire weather conditions to portions of Crook, Grant, and Harney counties. This shouldn`t be a long duration period of low RH`s lining up with breezy winds, but any ongoing fires in this area will be subject to some critical fire behavior. Currently don`t have enough confidence to issue a fire weather watch and conditions aren`t sustained for long enough to warrant it, but will continue to message the heightened risk alongside working with our partners to ensure we remain prepared for (hopefully) one of the last enhanced fire weather concerns of the year. Goatley/87 LONG TERM...Thursday through Monday... Models in good agreement with the PacNW entering a zonal pattern through Saturday. And with the arrival of the cold front, chances of showers occurring at the WA Cascades could increase for Thursday through Friday evening due to orographic lifting. However, confidence is on the low end (<30%). Breezy winds will develop up to 20 mph with increased westerly flow until decreasing to light Saturday (30-50% probability). A transient trough will then pass through the forecast area Sunday before an upper ridge takes over starting Monday. Winds will remain fairly light until breezy conditions return Sunday afternoon into Monday evening around 20 mph or less (40-60% probability). Though, models start to deviate a bit for Sunday. The GFS and ECMWF model both favor a shortwave trough passing through the forecast area, but with the GFS showing it slightly more deeper and the Canadian model remaining zonal. High temperatures will be mainly in the 70s through the long term period. Feaster/97 && .PRELIMINARY POINT TEMPS/POPS... PDT 79 53 89 57 / 0 0 0 0 ALW 82 56 90 61 / 0 0 0 0 PSC 84 57 88 60 / 0 0 0 0 YKM 84 53 88 55 / 10 0 0 0 HRI 84 56 90 58 / 0 0 0 0 ELN 83 55 87 56 / 10 0 0 0 RDM 81 48 91 52 / 0 0 0 0 LGD 78 50 86 57 / 0 0 0 0 GCD 78 50 87 53 / 0 0 0 0 DLS 86 58 94 60 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...87 LONG TERM....97 AVIATION...97