Tuesday, March 26, 2013

Late April Snow Potential Means Winter Not Done Yet

WARNING: The chances of this actually happening are essentially zero. DO NOT take this as an actual forecast. Take it as the smallest grain of salt known to man.

The long range CFS model is projecting an increase in snow depth across the Ohio Valley and Northeast in 2 of the 4 CFS ensemble forecast members. All of the ensemble members have an increase in snow depth across a portion of the northern US. While usually the agreement of all of the ensemble members of snow in some portion of the North US is encouraging to the validity of the forecast, I have a hard time believing that there will be a snow event in late April.

For one, the increased intensity of the sun greatly discourages snowfall potential. For another, the Northern Hemisphere's climate is naturally changing over to a springtime ''feeling'', with warmer temperatures covering a greater portion of the nature, and an increasing warm sector to the east of storm systems. However, with continuing chances for an unusually weak polar vortex, cold air will be relatively easier to come by, especially in the Northeast. To up the ante, an unusually active Pacific jet stream could draw in more cold air to the south, increasing chances for snow.

Again, this is almost certainly not going to verify, but the fact that the chance is even being suggested is a testament that this winter is unlikely to go quietly.


Sunspots Well Below Forecasted Numbers

It has come to my attention that the number of sunspots is well below forecasted values for this time of year. Shown above is a graphic from NASA, showing two different sunspot forecasts. If we use the small ticks on the (think back to middle school math here) y-axis, we find the 2010 mark predicts up to ~175 sunspots at this time. It is worth noting that these forecasts appeared on an article published in 2006. Regardless, both forecasts were showing very high numbers for the decade of 2010-2020.

Now shown above is an image of the last four solar cycles- Cycles 21, 22 and 23 are shown in blue, black and red respectively, while the in-progress Cycle 24 is shown in purple. If we look at the most recent observation of the sunspot number, we find that the number of sunspots currently stands at roughly 60- and we're at the height of the sunspot cycle! This means that the forecasts above were off by a minimum of 100 sunspots- a huge difference that shows just how weak the sun is, and raises questions about what its effects could be in the near future.

Short term, nothing major looks to be happening. Incredibly small temperature decreases in comparison to previous years are possible, and a decline in the number of solar flares and coronal mass ejections is probable. Long term, things get more interesting. If the sun does what I expect it to do, we are likely to see a multi-decade decline in temperatures across the world. We must remember that the sun has been recognized as the main driver of climate change, so the decrease in the number of sunspots (and thus the strength of the sun) should allow for at least a slight cooling trend in the world. I'm not willing to discuss global warming in this post, this is just pointing out how the forecasts for sunspots are off compared to what is being observed.


30-Day Sunspot Cycle in Turmoil

The 30 Day sunspot cycle that can help determine a variety of mesoscale factors has been sent into turmoil over the past month.

In the attached image, you can see how the sunspot cycle was fairly regular over the last several months. However, as of late, the cycle has essentially shut down and has been in the minimum of the cycle for the past month or more. The unusual quietness of the sun could help explain why the cold seems more prolonged and spread out. It also may assist in showing why there has not been persistent low pressure in the West US, as the 30 day sunspot cycle and Pacific-North American index have a negative correlation with one another.

Potential implications in the near future include continued instances of slightly prolonged and slightly stronger cold weather across the nation than what it would be if the cycle was at its regular. Other impacts include less pressure on the Central and East US to produce dominant high pressure. Rather, they would be more inclined to keep low pressure/general cool weather in the aforementioned areas.

If the cycle does not get out of its unusual antics in the next month or two, we could be looking at some solid impacts on spring, including the potential for increased instances of cold weather and slightly increased stormy patterns.


2013 Preliminary Atlantic Hurricane Season Outlook Release Date

The 2013 Preliminary Atlantic Hurricane Season Outlook will be released WEDNESDAY, MARCH 27 at 12:00 PM Central time.