Masters student in tropical meteorology at FSU. Raised in Alaskan blizzards, but drawn toward tropical cyclones by their superior PGF.
By: Levi32 , 4:11 PM GMT on November 12, 2007
This morning's NWS discussion:
".LONG TERM FORECAST...
ON THURSDAY A LOW IN THE SUB TROPICAL JET WILL REACH THE COLD AIR
ASSOCIATED WITH THE LARGE BERING/NORTHWEST GULF LOW AND EXPERIENCE
EXPLOSIVE CYCLOGENESIS. THIS LOW WAS A TROPICAL DEPRESSION SOUTH OF
JAPAN YESTERDAY AND THUS THE "BOMB" SCENARIO LOOKS REASONABLE.
NUMERICAL MODELS ARE STILL FIGURING THIS LOW OUT...BUT LOOK TO BE
TRENDING TOWARD A POSITION IN THE EASTERN GULF WHEN IT IS AT ITS
DEEPEST THURSDAY NIGHT. THE LOW WILL THEN MOVE NORTHWESTWARD TOWARD
SOUTH CENTRAL ALASKA BY THE END OF THE WEEK. WORTH WATCHING THIS
STORM AS HURRICANE FORCE WINDS ARE POSSIBLE WITH IT.
MARINE...GALE WARNING 120 150 155 160 165 170 172 175 179 185.
LUDWIG NOV 07"
Models are still on tap for a major low entering the Gulf of Alaska in 3-5 days. Tropical Storm Tapah and associated subtropical air will collide with a mass of Siberian arctic air, causing very explosive cyclogenesis and the "bomb" scenario. In Alaska the "bomb" is not any less of a bad thing as it is in the lower 48, despite the fact that people believe we should be "used" to them. Like the recent European storm, this will be a very bad situation for ships in the area, and what you might call a storm surge will be battering the coast for miles, although the threat of coastal flooding is minimal in this part of Alaska.
The track of this storm will be crucial to snow amounts in certain areas. Everyone is going to get the wind as the size of this thing will be huge. The GFS has been trending further east and south with this over the last couple runs, and the NWS as usual is following suit with their forecast. The NOGAPS and UKMET are the northerly models right now, which still take the low up east of Kodiak Island, meaning more snow for southcentral. All these solutions I expect to swing around a bit over the next few runs, as this is a very delicate situation that could unfold a number of different ways. The GFS seems to want to shove most of the energy eastward and out of the picture, while other models allow the low currently in the Bering Sea to pull the energy north, as in the figure below:
In the above image, the low is in the process of deepening and is still quite far south. The trough extension to the north of the low is what used to be the Bering low, which came east near Kodiak Island. This extension north is what could draw the energy closer to the coast, as some of the models are suggesting. Also evident in the image is the huge convergence boundary between warm and cold air setting up in the gulf. Lots of overrunning snow can be expected under that strong warm front. Bottom line this will be a very strong and dangerous storm and it's winds will be felt everywhere. Where the snow falls is entirely dependent on track, which is still to be determined.
The Bering Sea low that I mentioned above is currently strengthening and moving towards the SW coast today. This is going to provide us with several inches of snow in the 2 days prior to the big cheese. Snow lovers are really happy this week :)
We shall see what happens!
This image shows how TD 22w(now TS Tapah) and other ingredients are starting to come together to set up explosive development in 3 days. (Satellite image credit: Japan Meteorological Agency)
GFS phase diagram for the gulf storm. The intensity and size are notable, along with what appears to be a warm-seclusion scenario at peak intensity.
^Click for Loop^
The 986mb wave on the cold front of 976mb low in the above map is the disturbance moving east that will bring us some snow over the next couple days, and will also play a part in the gulf storm's track. The 988mb low on the western edge of the image is the low currently absorbing TS Tapah east of Japan.
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.