Hydrologic Outlook
National Weather Service Portland OR
235 AM PST Sat Jan 27 2024
…PERIODS OF HEAVY RAIN WITH RISING RIVERS THIS WEEKEND…
A complex area of low pressure offshore will maintain mild and moist southwest flow into the region through Sunday morning. This will bring rain, heavy at times, to northwest Oregon and southwest Washington. Rainfall of 1 to 3 inches is expected across the region, with 2 to 5 inches over the Willapa Hills, Coast Range and the south Washington Cascades through Sunday morning. Snow levels will be rising Friday, and hover at 7000 to 8000 feet through the weekend. Rain tapers off Sunday into Monday.
With all this rain, and snowmelt from the Coast Range and Cascades, rivers will be rising. Many small streams and creeks will be running high into Sunday. Heavy rainfall will cause water ponding in low lying areas and other areas of poor drainage.
In addition to hydrologic impacts, there may also be an elevated landslide risk. These particularly affects those areas that have seen significant tree damage due to then recent and strong east winds.
This morning’s river forecasts which are a little higher — they pushed the Wilson into Action Stage, Latest predictions for the Wilson River –
Cresting at 11.04 at 10 pm tonight, Flood Stage is 12.0′. The Nehalem River also will be at bankfull, and the gauge is currently not operating. The Pioneer has reported this to Tillamook County Emergency Management and the National Weather Service/NOAA have been notified.
Tillamook: It looks like we had a low pressure area form near the coast and move across the area this morning, coming ashore south of Tillamook headed to the northeast. This brought moderate, occasionally heavy rain through Tillamook County which has caused the rivers to climb but none are expected to reach Flood Stage though the Wilson River is expected to reach near bankfull. The good news for the Tillamook area is that the heavier rain is pulling off to the northeast leaving some light rain in its wake. We are seeing some increased southerly winds this morning along the coast, 15-20 gusting to near 40. Total rainfall for the last 24hr in the Tillamook area in the range of 2-3″ while some Coast Range locations are report between 3-4″.
More rain is on the way Tillamook with an atmospheric river of sorts developing with plenty of moisture on the satellite picture being pushed to the northeast in the persistent southwesterly flow. This means you can expect more rain with breezy southerly winds that do ease late tonight. With that strong and persistent southwesterly flow, the low tonight hangs at around 56.