Tropical Tidbits from the Tundra

Quick Note

By: Levi32, 3:57 PM GMT on November 30, 2005

Quick note before I head out of the house, Snow next Monday.

Cold Air to Move In.......Ridge Moving east in 5 Days?

By: Levi32, 5:04 PM GMT on November 29, 2005

Note: I will be unable to post again until Saturday because my brother is having eye surgery in Anchorage.

The pattern is still unpredictable this morning with the models changing their solutions all the time. However this morning we finally have a couple models that agree on a solution. These models are the Canadian and the Japanese model. What they predict is that cold air will take hold of eastern Russia and Alaska. The blocking high to the north of Russia will slide west. This frees up everything to move a little. The models say that heights will fall a little bit over Alaska. This makes the western trough want to move east. The ridge does move east a little. Though the models don't move the ridge all the way into the Gulf of Alaska where it belongs, we can assume that it will eventually. All the other models have different ideas, but some are coming close to this solution. I want to stress that I am not a model guy. I try to use common sense to predict what will happen. This solution does seem logical because it is what the cold air would force the ridge to do. I will leave the 500mb chart and satellite below:

N. Hem. 500 mb
You can see the flattening ridge, with cold air over the pole waiting to make its move south. Sure seems that a trough should form over the western Aleutians doesn't it?
Alaska IR Satellite

Wild Pattern

By: Levi32, 5:31 PM GMT on November 28, 2005

Here is a link to the GFS 12z North Pacific Loop

I put the above link up in hopes that it will help you all see What I'm talking about.

The only thing that I am sure about this morning is that somehow someway the trough will reestablish itself over western Alaska. The pattern is so complex right now it is hard to be sure about anything, but common sense tells me that the trough belongs over western Alaska. The main change this morning is the different model opinions. The GFS link I have posted shows a little bit of 2 different solutions. Around hour 96 it shows an upper low with cold air coming down into eastern Russia. This seams reasonable since the large area of northerly winds on the eastern side of the monster surface high over Russia would tend to bring arctic air into Siberia. The surface high then slides east, leaving the cold air stranded. We now have a belt of cold air stretching from eastern Russia across Alaska to western Canada. What that cold air does is the controversy. At 120 hours the GFS seems to be trying to form a shortwave over the Aleutians. The GFS then moves the shortwave into western Alaska and strengthens it little. In a previous run of the GFS the upper low over Russia dives into the shortwave and deepens rapidly as it moves over the Alaska Peninsula. The result is an intense low that reestablishes the trough over western Alaska. This is one solution that needs consideration. This latest run, though, deepens the shortwave farther east, resulting in a strengthening of the western Canada trough. The ridge out west builds in response. Here we go again. But wait, the GFS then moves a big low under the ridge. The ridge repositions over the eastern Gulf of Alaska. The trough is reestablished.
Hard to say which solution will come to pass, or if any of them will. Just have to play it by ear.

Here is the latest N. Hemisphere 500 mb Analysis Chart:

N. Hem. 500 mb
You can see the flattening ridge, with cold air over the pole waiting to make its move south. Sure seems that a trough should form over the western Aleutians doesn't it?
Alaska IR Satellite

Stormy Pattern Back Within a Week

By: Levi32, 2:47 AM GMT on November 28, 2005

The main change today is that the ridge out west will probably stay flattened. The significance of that is that it will allow the alaskan trough to reestablish itself sooner that previously thought. First of all, the fate of the ridge is determined by 2 lows coming off Japan. The first one is already making its journey across the western Pacific. The second one is just coming off Asia as a weakling, but it will strengthen rapidly as it moves toward Japan. That is the big event. When the second low rapidly strengthes, it will pump the ridge in front of it. This will rob the pacific low of the baroclonic instability it neads to develop. The pacific low will then weaken and move east. The result is a flattened ridge with no more lows to pump it back up. Cold air takes over at that point. The monster surface high north of Russia will propel arctic air south into Siberia which will inhibit any more growth of the Bering Sea ridge. Cold air will then invade Alaska from the pole. This will force the next series of lows south of the Aleutians and into the gulf of Alaska. The cold air will then dive south into the trough and reestablish it over western Alaska. This will once again steer storms into the Mainland.

Alaska IR Satellite

BIG POST on Alaska weather pattern for the next 2 weeks

By: Levi32, 1:49 AM GMT on November 27, 2005

Forgetting the short term for a moment, let's look at the big picture for the long range. Right now the trough that has plagued Alaska with storms for the last couple of weeks is moving east and allowing a ridge to push its way into the Bering Sea. A long front is on the back side of this ridge, making slow progress eastward. This setup of trough moving east and ridge nosing in from the west has happened once already this winter, in late October and Early November. At that time there was a strong upper level low over the interior of Alaska. This forced the ridge to split, resulting in a blocking high over siberia, and leaving the lower part of the ridge no choice but to flatten and move under the upper low untill it reached the eastern gulf of Alaska. The upper low then dove southwest into the trough that was waiting for it.
I think that something very similar will happen with this ridge. Currently there is no upper level low over Alaska, so I think the ridge is unlikely to split during the next 3 days, but it might flatten. You see, the big front over the western Aleutian Islands is supposed to move over the top of the ridge and dissipate over SW Alaska. This would happen if the wave low south of the Aleutians curves northwest and takes the current position of its parent low. Cold air on the back side of the low now begins to cut it off from the ridge. The ridge is then left flattened. Now you're saying, "It should move under the upper low now and a trough will take over." No, you are forgetting that there is no super cold air around. The pattern is mostly zonal at this point. The ridge is then re-pumped up by some surface lows coming out of Japan. By this time, though, there is a mass of arctic air moving westward out of Canada. This is what we have been waiting for. The cold will then make a move into interior Alaska. The timing of this move is crucial in determining when the next storm moves into Alaska, and how strong that storm is. Once placed over Alaska, the cold air will finally force the ridge under the upper low, and the upper low will dive into the waiting trough. This will direct storms once again into Southern Alaska.

I will leave Radar and Satellite below:

Alaska IR Satellite

Quieter Weather Ahead

By: Levi32, 6:31 PM GMT on November 26, 2005

Note: I have added the Middleton Island radar loop to the bottom of the post so you can monitor the motion of the surface low and the snowshowers.

There was no round 3, but I don't think anyone wants more snow on top of 2 feet. The low is still hanging out in the western gulf producing showers for Prince William Sound and the north gulf coast. Some of those showers may make it across the Kenai Mountains and affect the western Kenai Peninsula, but it should be a nice day with sunshine throughout. It will be cold though. The temperture right now at my house is 5 degrees.
On Monday a weak front will pass over the area from the Bering Sea bringing areas of snow. The pattern thereafter will be less stormy with the ridge over western Alaska and the Bering Sea steering storms far to the south or keeping them west. The only precip south central Alaska will get is from weak systems overtopping the ridge and moving over the area.

Kenai Peninsula Radar
Middleton Island Radar
Alaska IR Satellite

Round 2 over......Round 3?

By: Levi32, 2:44 AM GMT on November 26, 2005

Round 2 of one of the worst November snowstorms in Homer's history is over. The results? a solid 2 feet of snow, bringing the snow pack up to 30 inches. I just came in from snowblowing part of our driveway, and boy am I cold. It was above my waist in parts!It has stopped snowing, and now the snowplows can finally start cleaning up the place.
Is there more to come though? You see, the reason for this blizzard was the more northerly position of the kamishak gap wind jet. A jetstream of wind is constantly racing out of the kamishak gap on the east side of the Alaska Peninsula, and it usually flows over the Barren Islands south of the Kenai Peninsula. But today the low east of Seward pulled the wind stream to the north, aiming right into Kachemak Bay. The result was heavy snow showers forming off the water and impacting the coast. The reason we might get more snow is because the low will hang around for at least another 18-24 hours, and also because even though the snow has stopped here, the radar still shows a heavy band of snow across the bay. That is confirmed by the report of heavy snow in Seldovia. Even if we don't get more, the mess will be hard to clean up.

Kenai Peninsula Radar
Alaska IR Satellite

Unexpected Snowstorm for Homer!

By: Levi32, 4:22 PM GMT on November 25, 2005

Updated for snow amounts and warnings:

Finally the slow Weather Service issued a Blizzard warning for Anchor Point south on the western Kenai Peninsula. Expected visibilities under 1/4 of a mile and additional snow accumulation of 7-10 inches, on top of the foot and a half we already have! I expect these conditions to last into the evening. I'll leave the rest of my last post unchanged below:

WOW! That's all I can say after what happened last night and continues to happen as I type. All the windows are plastered with white, and a new shed we just build is in danger of collapsing from all the snow. We have about a foot and a half so far, with the snow stake showing 28 inches on the ground total, and it's still howling and snowing hard. Anyway, the satellite image below tells the tale. NW winds and cold air advection have been racing accross the western part of the state for the last 2 days. You can see the low level clouds over cook inlet and parts of south central Alaska. Those are convective showers which are somewhat like our own lake effect snow. They form when cold air moves over the warm inlet. You can also see that some of the showers are finally showing up on radar. Up until this point they have been totally non-existent on radar.
This settup is not going away for the next couple of days, so there is no telling when this will stop. If the atmosphere remains unstable, then we may end up with 12-18 inches before it is all over. Not to mention the drifts, which are just covering everything we try to clean off. The roads are perilous, totaly blown over, it's amazing. It's also very very cold. the ambient temperature is 11 degrees, but the wind chill is down near 30 below. Bring on Christmas!

Kenai Peninsula Radar

Alaska IR Satellite

Snow closing in

By: Levi32, 4:19 PM GMT on November 24, 2005

The mass of snow is staying farther north than previously thought. Anchorage will still get 4-6 inches, but areas farther south will have only isolated snow showers.
Cold advection on the back side of the low will wring out moisture on Homer with 2-4 in. of snow as a result.

Alaska IR Satellite

Next storm for SE Alaska

By: Levi32, 5:13 AM GMT on November 24, 2005

As you can see from the satellite picture below, the moisture from the storm south of the Gulf of Alaska is making its way north towards the north gulf coast. heavy raing has been falling in the southeast panhandle most of the afternoon, and it will only get wetter and warmer. The main problem today is whether or not the overrunning snow will make it far enough west to effect the Kenai peninsula and the Anchorage bowl. I suspect that just like the last system, the moisture shield will make it to the Anchorage bowl and give them some more snow, but no farther. However, the strong cold air advection on the backside of the low may cause some showers and snow squalls to form off the water near the east side of the inlet and Kachemak Bay. This is what happened this afternoon in Homer and it continues to snow as I type.

After this storm the flow will become more zonal and cold air with partly cloudy sky's with isolated snow showers will rule for the next 4 days.

Alaska IR Satellite

Snow in Homer, AK

By: Levi32, 2:09 AM GMT on November 24, 2005

Boy are we getting winter weather to the max here in Alaska colder than normal and a white thanksgiving for the first time in 5 years. As I write snow squalls are battering the area with 35 M.P.H. winds and whiteout conditions.

Happy Thanksgiving!

Latest Alaska IR Satellite Image:

Alaska IR Satellite
Homer is on the southern end of the Kenai Peninsula, which is on the south central coast in the center of the picture.

Here is a sweet picture of Hurricane Wilma from space (be patient, large picture)


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Tropical Tidbits from the Tundra

About Levi32

Masters student in tropical meteorology at FSU. Raised in Alaskan blizzards, but drawn toward tropical cyclones by their superior PGF.

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