Masters student in tropical meteorology at FSU. Raised in Alaskan blizzards, but drawn toward tropical cyclones by their superior PGF.
By: Levi32 , 5:27 PM GMT on December 18, 2008
There's lots of excitement in southcentral Alaska today. After dumping several inches of snow on the Kenai Peninsula yesterday, a slow-moving low pressure system is beginning to move off towards the east. Scattered snow showers remain north of Clam Gulch and reaching into the Anchorage Bowl. These showers will gradually diminish by tomorrow afternoon. Strong winds and single-digit temperatures on the back side of the low will generate nasty wind chills tonight and tomorrow throughout the area.
Down in Homer and Anchor Point some places are still experiencing blizzard conditions with 3-5 inches of new snow so far today. You may ask how is that possible if I see nothing on the radar loop? That's because the part of the peninsula south of Anchor Point is experiencing their version of lake-effect snow, similar to the Great Lakes region in the lower 48. In the SW quadrant of a storm such as this one that brings in an arctic airmass behind it, strong winds blow over the waters of Cook Inlet. These waters are much warmer than the air flowing over them, and so the atmosphere becomes unstable because warmer air near the ocean surface wants to rise. Shallow storm cells form over the water as a result, and are undetectable by radar because they are too low. Despite being shallow, these snow showers can get very intense and can drop several feet of snow at times if the low to the northeast sits in the same spot for a while. People along the coastline of Kachemak Bay get this the worst because the winds funnel right up the bay and stay over water longer than if they were just crossing the inlet.
The current snowfall will begin to taper off in about 12 hours as the 500mb vort max, currently over Bristol Bay, moves to our east and the flow aloft becomes dry out of the northwest, as opposed to the current moist flow out of the southwest.
As for the longer term, the developing pattern with a waning La Nina and cold over the eastern United States is going to set up a trough over Alaska for the next 10-15 days, which will flatten any ridge which tries to nudge it out of the way. This will set up 2 primary storm tracks: 1) Straight from the south out of the eastern Pacific and up into the gulf. 2) Riding the Aleutian chain from the west and southwest and skimming under or over the southern Alaskan coasts and into the gulf or southern interior. This will mean lots of snow during these systems and cold arctic air behind each one as they pass, spaced 2-3 days apart. Overall it's looking like February will be a very wintry month!
We shall see what happens!
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Mount Redoubt's unrest continues to intensify today. Seismographs and reports from the Alaska Volcano Observatory show increased action under the mountain. According to AVO no eruption has yet occured, despite several very intense episodes of seismic activity this morning. Current watch level is still at ORANGE. More information can be obtained from the AVO website.
Current Seismograph near the summit of Redoubt:
Current Ash trajectory forecasts (valid 10:00pm AKST tonight):
Current Redoubt Webcam:
Current Redoubt Webcam from across Cook Inlet:
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