It's beginning to feel a lot like autumn already for much of Alaska, as temperatures have dipped below the declining seasonal normal in the past few days. Sub-freezing temperatures occurred in many of the colder spots of the central and eastern interior this morning, including in the Fairbanks area: 27°F at Goldstream Creek and 31°F at the Creamers Field SNOTEL site. The early chill will hasten the arrival of autumn colors in the next couple of weeks.
I've been too busy to post my usual monthly climate update in recent days, but better late than never - here's a look back at climate anomalies in the month of July. It was a fairly warm month overall, and significantly drier than normal on a statewide basis, which marks a big contrast with last year's record wet July. Warmth was widespread (except for Southeast), but the dryness was most significant along and north of the Gulf Coast from Cook Inlet to the far northern Panhandle. Here are percentile rank maps from NCEI (top) and ERA5 reanalysis (bottom):
As usual, the NCEI and ERA5 maps differ significantly for precipitation, with ERA5 showing much wetter conditions from the western interior to the Alaska Peninsula and Kodiak Island; and ERA5 also highlights the unusually sunny and dry conditions across the North Slope.
One of the most significant events during the month was the
heatwave focused on northwestern Alaska early in the month. Rick Thoman comments a bit more on this in his blog:
Wind was above normal in the zone of wet and cloudy weather across the southwest. This region of poor weather seems to have been caused by a frontal zone along the eastern side of the (quasi-permanent) Bering Sea trough; as the second figure below illustrates, there was a subtle north-south ridge axis over Alaska, blocking the westerly flow. The more significant upper-level feature was a ridge over the East Siberian and Alaskan Arctic Ocean, and that was a key player in the northern heat wave:
Regional lightning activity was not far from normal for the month overall, based on lightning strike counts that include northwestern Canada; but it was more active in parts of the Alaskan interior, and especially north-central areas. As is typical, most of this activity occurred early in the month, including well over 10,000 strikes on the 7th. It appears this is the first year (2012-present) with over 10,000 cloud-to-ground lightning strikes on 5 different days during summer, based on data collected by the Alaska Lightning Detection Network. I'll have more to say about this summer's lightning and wildfire activity in a subsequent post.
On a road trip and was expecting to warm up a bit in Fairbanks relative to our cool coastal weather, but feeling a little cheated. Wet and cool, with enough breeze to make it feel that much worse. Fleece and stocking caps are in order if you are outside much. Yesterday's high of 52F was ~15 degrees F below the norm.
ReplyDeleteHi Jim, sorry to hear that. Unfortunate timing - it was 71F only two days earlier. The high of 52F is the earliest for such a chilly day since July 31, 2008. Last year the chill arrived a week later.
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