Interior Alaska finally saw some genuinely warm weather last weekend, with temperatures pushing up toward the 80°F mark in many areas; and Fairbanks saw its first 80°F of the season - a few days later than normal.
The mini-heatwave didn't last long, but renewed warmth is on the way in the coming days, and the predicted mid-atmosphere pressure pattern looks conducive to the onset of more widespread lightning in the near future. The map below shows the expected 500mb height anomaly (departure from normal) for the next 7 days, indicating a broad axis of above-normal heights (i.e. a ridge) from eastern Russia to northwestern Canada:
Contrast the pattern in the first two weeks of this month, when a strong trough over the Arctic Ocean brought cool northwesterly air flows to interior and northern Alaska:
Atmospheric moisture has been well below normal for the time of year, and that means a lack of atmospheric fuel for thunderstorms.
No surprise, then, that statewide lightning activity is below normal and is now moving into "significantly below normal" territory; the climatological median ramps up quickly from June 15 on. Click to enlarge:
Thanks to the lack of lightning, year-to-date fire activity is close to zero: only 5600 acres have burned statewide so far, compared to a historical median of 85,000 acres for this date. In view of the weather forecast, this seems likely to change soon.
It's also worth noting that the past two weeks have been quite dry for most of the interior, a marked change from the wet spring; fire fuels have no doubt dried out quite a bit.
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