Long Range Lookout: Winter Slipping Away

Preword: Recently, I have been caught up in the swing of the stratosphere and investing all of my confidence in just a few factors. Starting today, I will present the good and bad sides of the forecasted weather, even though you may not find it as exciting as my other posts.

In a disastrous recurrence of last winter, the winter of 2012-2013 has so far brought little snow and only modestly increased cold in comparison to last winter. Don't get me wrong, this winter has had many more advantages than last, but still remains dismal. The long range will be a classic, painstaking case of some factors looking good while other factors ruin the party. We start with the current 500 millibar anomalies over the Northern Hemisphere. Blues indicate low pressure areas and reds show high pressure regions. Deeper shades of each color indicate stronger modes of their respective pressure systems. We can see a deep blue positioned over the Great Lakes in the wake of a very powerful storm system that impacted much of the nation's population. This area of cold will move on out of the region later on as we head towards the weekend. I want to turn your attention to eastern Asia in the upper right-hand corner of the image. See that massive high pressure system there? That will provoke high pressure in the United States as we enter next week and into the following weekend, and we could see another bout of above normal temperatures. Snow cover that was received in the past couple of days could be eradicated. This comes at a time when high pressure finally emerges into the West Coast, a good sign for cold and snow in the Midwest and East US. But, as a result of the forecasted high pressure system, it will be Alberta clippers that bring the best chances for snow.

We now move ahead to Mid-February. There is no longer high pressure over East Asia, but persistant low pressure anomalies. These low pressure anomalies would then inspire a stormy period to round out the month of February. Could these storms hit the Northeast? I'll discuss that a bit later down this article. Something that certainly is not good is that persistant low pressure in the Bering Sea. This goes with my 'some good, some bad' forecast, as this persistant low pressure in the Bering Sea can lead to above normal temperatures in south-central Canada and much of the northern United States. Even more depressing is the lack of Greenland blocking. Greenland blocking is the phrase that is used to reference persistant high pressure over Greenland. When that set-up happens, the atmospheric pattern is more inclined to introduce more wintry weather into parts of the US. A lack of this blocking leads to a more zonal, west-to-east jet stream that allows for warm temperatures and not many storms. It is very possible some of that high latitude blocking in eastern Europe (shown in deep reds) could migrate over to Europe, but that remains to be seen. Frankly, I'm not that optimistic on the idea. This dismal explanation is verified by slight high pressure in the New England area, likely as a byproduct of the low pressure in the Bering Sea, and in response to a lack of Greenland Blocking. One bit of good news is the forecasted high pressure over the Pacific Northwest. If you get high pressure in that area, the jet stream can be persuaded to dip south and let out some cold into the Northern US. Storms tend to follow a jet stream that favors wintry weather for those same regions, the Midwest and Ohio Valley for example.

Lastly, looking ahead to the heart of February just a few days after the above image, we find that the atmosphere has changed. That high pressure that was in the Pacific Northwest has now migrated into the Gulf of Alaska. This situation can then go one of two ways. The first option is for high pressure to then spread back on land into the Pacific Northwest, or the high pressure pushes west into the Bering Sea. Both moves would support a cooler pattern in the North US, but I'm not betting on it at the moment, as the consensus is not overwhelming and we are over 2 weeks away from this forecast image. We still see persistant low pressure in East Asia, adding to my theory of a stormy end to February. Also, we then see the forecast emerging for some spotty patches of high pressure in and around Greenland. Such an action could provoke a better pattern for the Northeast (notice the high pressure in New England is gone), but it's too far out for me to think about accepting or rejecting this idea.

So we could see some storms in late February, but the big story will be warmth in mid-February, with Alberta Clippers dominating that scene. Early February will be when the effects from the sudden stratospheric warming dies off, so that will add to the troubles the cold may face in the coming month.

Andrew

February 18-19 Potential Winter Storm

I am watching the timeframe of mid to late February for some wintry weather across parts of the nation.

The reason I post about this long range potential is because of a repeating pattern called the Lezak Recurring Cycle. Every fall, this pattern sets up and repeats itself every 40-60 days. That cycle length varies from year to year. This year's length is 53 days. If we go back from February 18-19, we find ourselves at the very last days of December. Looking at the 500mb map for December 29 (top image), we see a couple bumps in the contour lines, displaying low pressure systems. This could indeed produce some wintry weather within the Midwest and Great Lakes. A day later, on December 30th (bottom image), we see that the storm has shot offshore and is now impacting the Northeast.

This storm will depend on the atmospheric pattern that is in place when the system comes through. Looking at some very long range indicators, I see that this storm would indeed favor the Midwest and Ohio Valley for wintry weather. However, a lack of high pressure over Greenland could make for a more inland track that may promote more wintry weather for the Upper Midwest rather than the lower Midwest, but that is all TBD.

Andrew

February 14-16 Potential Winter Storm

If you're not into repeating patterns, this post is not for you. If you want snow, read on.

I am watching closely for the potential of a winter storm from the 14th of February to the 16th; these dates are very fluid.

The reason I post about this long range potential is because of a repeating pattern called the Lezak Recurring Cycle. Every fall, this pattern sets up and repeats itself every 40-60 days. That cycle length varies from year to year. This year's length if 53 days. If we go back from February 14-16, we arrive around the December 25-26 timeframe. If we take a look at the 500mb chart from December 26th (pictured above), we can see a storm system impacting the southern Midwest, spreading precipitation throughout the region. The Midwest and Ohio Valley would be impacted by this storm if it follows the same track as the December 25 storm did. Looking ahead to the last days of December, this storm then progressed to the Northeast. Could we see that region impacted by this system? That's not clear right now. The reason is that February may not feature as much high latitude blocking as previously thought. If this blocking does not appear near Greenland, the atmospheric pattern would not be favorable for coastal storms, and then this storm track may take a more inland pattern.

But again, this is based off the LRC pattern and does have bust (failure) potential. I post about it because this pattern has fared well this winter, and should perform well as the winter progresses.

Andrew

February 9-12 Potential Winter Storm

There is increasing potential for a winter storm occurring between the 8th and 12th of February.

The GFS model has been continuously hinting at a storm system ejecting from the Plains around the 9th of February and moving east. As it does so, the storm rides along the freezing line, which is shown above in the southernmost dashed blue line. As the GFS model forecasts above, the storm produces abundant snow across the Plains, Midwest and Ohio Valley. Previous forecasts have shown accumulating snow to occur in these areas, although exact amounts are to be determined.

The reason I post about this long range potential is because of a repeating pattern called the Lezak Recurring Cycle. Every fall, this pattern sets up and repeats itself every 40-60 days. That cycle length varies from year to year. This year's length if 53 days. If we go back 53 to 54 days from February 11th or so, we find ourselves with a very similar piece of energy in the Plains. No doubt that the LRC is indeed behind this, and its support is a big part of why I am posting about it. I find that there could be low pressure along the West Coast, something that could push this storm more towards the Plains, once again shafting the lower Great Lakes in favor of the Upper Midwest. However, if the storm adheres to the LRC pattern, cities like snow-starved Chicago could see some snowfall out of this, but again, the specifics are TBD.

Andrew

January 29 Severe Weather Event -- Updated 4:00 PM

Moderate risk continues to be in effect for Arkansas, northern Louisiana, northern Mississippi, eastern Tennessee, eastern Kentucky, southern Illinois and southeast Missouri.

As of 4:00 PM CT... strong thunderstorms were ongoing across the Plains into the Midwest, with severe weather warnings beginning to be issued as the storms move into a more favorable environment. Special noontime sounding from southern Missouri shows differing wind speeds at different levels, consistent with observed strong wind shearing in the same areas. Analog comparisons to similar soundings reveal at least one tornado did occur in a similar situation. Surface helicity observed to be quite strong, would expect an increasing tornado threat as the night goes on. However, an already-established linear severe weather event will make it hard for stronger tornadoes to evolve, hence the extreme damaging wind concern. Current lower level wind forecast indicates strong winds of over 50 knots. I anticipate these winds to increase dramatically as the evening wears on in response to the nocturnal lower level jet stream mixing with these thunderstorms and really firing them up. By that time, the damaging wind threat will take center stage, enabling many n the moderate risk area to achieve warning-criteria wind speeds.

Today is indeed a Critical Storm Action Day. All resources are now devoted to the severe weather situation, and no posts unrelated to the severe weather situation will be published.

Next update will be at approx. 5:30 PM CT

Andrew