063 FXUS66 KPDT 042311 AAA AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 411 PM PDT Sun Apr 4 2021 .Updated aviation discussion .SHORT TERM...TODAY THROUGH TUESDAY NIGHT...The cold front, associated with the digging trough, is currently transversing our area as winds continue to increase and shift from southwest to northwest this afternoon. A Wind Advisory has been issued for the Kittitas Valley until 9 PM tonight, as current observations across the valley have incurred advisory criteria wind speeds and gusts. The thermal gradient has allowed for gusts of up to 55 mph to occur, peaking over the next 6 hours before slowly subsiding tonight into Monday morning. Winds are also expected to be quite breezy across the region as the front passes, but should stay below advisory criteria as these areas are less influenced by the thermal gradient due to its orientation. Precipitation has mainly stayed to our north with this system, but will drop into our area later this evening. The Basin should stay dry, with the majority of precipitation occurring in the mountains. The Northern Blues should receive some snowfall on the back-end of this system tonight into early Monday. Expecting a minimal amount of snow, as the WA Cascades and Blues could pick up 0.5 to 1 inch, and the OR Cascades staying less than 0.5 inch. The big takeaway from this system will be the cooling temperatures behind the front. High temperatures will drop 5 to 10 degrees from tonight into Monday, hovering in the mid-to-upper-50s range as the lows stay relatively unchanged in the low-to-mid-30s. Snow levels will also be dropping overnight tonight between 1000-2500 feet before rebounding back between 4000-5000 feet by Tuesday. A weak ridge builds just behind the departing system on Monday, bringing a return to drier conditions. This ridge stays through and into the extended period, keeping conditions dry and winds calm through Tuesday. 75 .LONG TERM...Wednesday through Sunday...Wednesday through Friday will be met with a westerly flow aloft and a few embedded waves bringing snow/rain showers to the Cascades with a chance of snow/rain showers over the eastern mountains. In general, snow levels will be around 3500-4500 feet during the day and 2500-3500 feet at night. Occasional breezy winds can also be expected during this time. Models are in general agreement for the PacNW through the end of the work week but fall out of alignment during the weekend. Despite the differences, models show some form of a trough around Saturday but the strength and timing are in question. Most ensemble members are clustering around a trough over BC and Washington with a strong westerly flow beneath the trough over Oregon. At this time, it does not appear to be a late season heavy snow pattern for the mountains and valleys but this could change if the trough becomes more amplified and organized. The trough may also bring gusty winds to the area. NBM currently keeps PoPs less than 15 pct for Sunday but confidence is low based on model inconsistency and a continued westerly flow. Wister/85 && .AVIATION...00Z TAFs...VFR conditions will prevail for the next 24 hours. A weak disturbance may bring some -SHRA to KPDT and KALW this evening, but elsewhere will remain dry. It will be breezy with winds locally as high as 15-25 kts, especially in the Lower Columbia Basin and adjacent valleys. Winds will diminish late this evening, and clouds will also decrease as the weather disturbance departs the area. && .PRELIMINARY POINT TEMPS/POPS... PDT 33 57 32 66 / 20 10 0 0 ALW 36 58 37 67 / 40 10 0 0 PSC 35 63 35 69 / 20 0 0 0 YKM 30 64 32 69 / 0 0 0 0 HRI 33 63 33 70 / 20 0 0 0 ELN 30 60 32 64 / 0 0 0 0 RDM 23 57 22 68 / 10 10 0 0 LGD 32 50 29 62 / 30 20 0 0 GCD 32 51 31 65 / 20 20 0 0 DLS 35 62 35 67 / 0 0 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...Wind Advisory until 9 PM PDT this evening for WAZ026. && $$ SHORT TERM...75 LONG TERM....85 AVIATION...88