"Disorienting" Moisture, Rainfall Records In N. Alaska, Unprecedented Drought In SE Of State
August kicked off with a disorienting feed of tropical moisture from the typhoon-pockmarked Northwest Pacific into northern Alaska. Such atmospheric rivers do make their way into Alaska, especially in late summer, but in this case the moisture brought drenching rains across a vast area, including the heaviest 24-hour rainfall on record for Nome (2.43” on August 1-2), as well as widespread flooding.
Early this week, another soggy surge of upper-level moisture swept into southwest and central parts of Alaska. The new surge will contribute to heavy rains across central Alaska that could lead to additional flooding later this week. With 4.28” of rain this month through Tuesday, Fairbanks could top its August precipitation record (6.88”, from 1930) by this weekend. And the moisture plume itself is already a record-breaker. At several locations separated by hundreds of miles, Tuesday brought the wettest atmosphere ever observed in the 70-plus years since regular radiosondes (weather balloons) have been launched over Alaska. This is based on precipitable water (PW), the amount of moisture in a column of air above the surface.
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For perspective:
—There was more moisture in the air on Tuesday night above Anchorage than there was above Corpus Christi, Texas (1.73”), which sits on the Gulf Coast.
—The amount of water above Anchorage would have beaten the all-time record for Salem, Oregon (1.73”).
With the main jet stream absurdly far north, parts of southeast Alaska that are typically moist have been markedly dry this month. Even with the record amount of moisture sitting above it, Anchorage was able to squeeze out only a trace of rainfall on Tuesday. The city has seen no measurable rain all month—something that’s occurred on August 1-13 only once before (1969) in airport records going back to 1954. No rain is expected in Anchorage for at least the next week.
Juneau hasn’t seen measurable rain since July 29, making this the first August in 124 years of recordkeeping to go this long without rain. The city could get some sprinkles or spritzes starting Wednesday, and perhaps a bigger dose of rain toward the weekend.
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https://www.wunderground.com/cat6/Bizarre-Happenings-Far-North-Lightning-Tropical-Moisture-and-More