Masters student in tropical meteorology at FSU. Raised in Alaskan blizzards, but drawn toward tropical cyclones by their superior PGF.
By: Levi32 , 6:16 PM GMT on November 11, 2007
A severe and potentially life-threatening weather event is shaping up this week for southern and southeastern Alaska. The trough which brought us 8 inches of snow yesterday will move out and be replaced by a weak ridge today, followed by a shortwave tomorrow. Under this shortwave a weak low will cross the Bering Sea from the west spreading light snow over western and southern Alaska Tuesday and Wednesday. This low will be dragging a lot of cold Siberian air with it, and the polar jet will dip quite far south as the low moves east.
What is now TD 22w in the west Pacific will be nosing into our vicinity in 3-4 days, converting to extra-tropical as it goes. This system, having originated from the tropics, will have a strong sub-tropical connection as it moves north. This mass of warm air will collide with the cold Siberian air in the Bering Sea, causing explosive cyclogenesis in the Gulf of Alaska. Here's what this morning's NWS discussion had to say:
"Long term forecast...
the Bering Sea low will continue to move southeast setting up what
looks like a major Gulf storm later in the week. The upper low will
pull cold air off of Siberia in the polar jet. This will consolidate
with the subtropical jet...which currently has a strong tropical
connection. Indeed...what is at least a tropical storm (possibly a
typhoon...I have not had time to explore this more fully) will go
extra-tropical and move into the Gulf of Alaska and undergo
explosive cyclogenesis as it inhales the siberian air. Many ensemble
members show a surface low in the 940s by 18z Thursday...and the 00z
run of the GFS drops the surface low to 937 mb. With this sort of
strength and development hurricane force winds would be likely.
Exact timing and location are still in question of course...but a
major event is shaping up for later in the week somewhere in the
Ludwig Nov 07"
As Ludwig said the models are jumping all over the intensity and size of this system. A large radius of 80+ knot winds on the back side of this monster is likely. As far as track goes, the GFS keeps the low just far enough south in the gulf to spare the coast a major snow dump, and splits a piece of the energy in the form of a secondary low to the southeast. The southeast panhandle will get the full brunt of the storm with this scenario. The ECMWF, CMC, and Japanese models move the low further north, increasing snow chances. The ECMWF really wraps this up, pulling the secondary low right up into Prince William Sound, which is the classic position for a major snow event over Anchorage and the Kenai Peninsula. Within the next few days the position and track should be narrowed down, but regardless of where the snow gets dumped, the wind radius of this will be massive, and everyone is going to feel it. Bottom line is we're looking at possibly one of the biggest storms we will see this winter, and conditions could become life-threatening in some areas during the course of the storm.
We shall see what happens!
This image taken this morning shows TD 22w being caught up by an extratropical low on its way east. This storm will eventually end up in the Gulf of Alaska as our big cheese later this week. (image credit: Japan Meteorological Agency)
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