Barometric Pressure Forecast for Merlin, Oregon
Barometric pressure forecast for Merlin, Oregon — on the Rogue River northwest of Grants Pass, tucked into the Klamath Mountains of Josephine County. See current barometric pressure and what it means for weather-sensitive people.
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Pressure and weather in Merlin
Merlin sits at about 950 feet where the Rogue River leaves the broad Grants Pass basin and enters the canyon country downstream, ringed by the steep forested ridges of the Klamath Mountains. The Coast Range stands between here and the Pacific, and the Cascades rise to the east, which puts the Rogue Valley in a double rain shadow and makes it markedly drier and sunnier than the Willamette Valley to the north. Pacific frontal systems still bring the pressure changes, and from November through March a strong front or an atmospheric river aimed at southern Oregon will drop the reading fifteen to twenty-five hPa over a day before it rebounds behind the cold front. Between those storms the valley does something that matters more to people here than the storms themselves. Cold, dense air drains off the surrounding slopes at night and settles on the valley floor, and under a winter ridge it can stay there for a week or more, capped by an inversion with grey fog beneath and sunshine on the ridgetops. During those spells the barometer sits high and nearly motionless for days. Summer is dominated by the inland thermal trough and, in recent years, by long stretches of wildfire smoke trapped in the same valley that traps the winter fog.
What this means for you
This valley alternates between stormy Pacific weeks and long, flat, high-pressure inversions. Watching current barometric pressure makes the difference between the two obvious in your own log.