Posted: Sep 21, 2012 3:55 PM by Dennis Bragg - KPAX News
Updated: Sep 24, 2012 11:17 AM
MISSOULA - National Weather Service forecasters say the massive ridge of atmospheric high pressure anchored over the Northwest is showing "phenomenal strength." And the resulting drought is actually being caused by weather patterns happening on a global scale.
Look out your window and your perspective on the impact of the West Coast high pressure probably doesn't extend much further than the wall of smoke choking the valleys of Western Montana, but at the National Weather Service office in Missoula, forecaster say the smoke extends north of Idaho into Canada and the Yukon.
From forecaster Trent Smith's desk, the view has been the same for weeks. "It's just a really big ridge and it will take some big dynamics in the global pattern to finally break this system down."
A normal year would see a system or two cross the Northwest by now, but this time the only systems punching through have fanned fires without bringing rain.
"We've actually had a couple of cold fronts come through in August and the early part of September. But it's only brought wind and no precipitation," Smith said.
"Earlier in the spring and summer this ridge was right over the top of Central and Eastern United States, causing extreme drought conditions in those locations. But the pattern shifted come about August, July-August timeframe and the ridge set up over the top of the Western United States."
It's not only tough predicting when the high will break down, but also the impacts of the region-wide fire smoke.
"One of the bigger things that's been difficult is to keep on portraying the effects of smoke and talking about the smoke day in and day out has been a real challenge here."
Regardless of when conditions change, this is already one for the record books in both the lack of rain, and also temperatures. ]
There were 19 days of 90 and above in July and another 16 days in August, so this will end up being the fourth hottest record on summer, not far behind the hottest year ever in 2007.