- Joined
- 24 December 2005
- Posts
- 2,601
- Reactions
- 2,065
He is talking about the positioning in the ocean of the warm currents Knobby. This stuff is heavy and needs to be read carefully. He is suggesting this positioning of warm currents is causative of colder weather in certain areas.
In recent history, strong El Nino’s that were “eastern-based” generally have been associated with warmer-than-normal winters in the eastern US whereas “centrally-based” weak-to-moderate El Nino’s have been often correlated with cold and snowy winters. For instance, two strong and "eastern-based" El Nino’s that resulted in warm winters in much of the eastern US took place during the winters of 1972-1973, 1982-1983 and 1997-1998. On the other hand, two weak-to-moderate El Nino's that were "centrally-based" and resulted in cold and snowy winters occurred in 2002-2003 and 2009-2010.
There are a couple of reasons why a weak-to-moderate strength and "centrally-based" El Nino can increase the chances for a cold and snowy winter in the eastern US. First, the higher the temperature of the ocean, the more water vapor is released into the atmosphere and this extra moisture tends to energize the southern branch of the jet stream. An activated southern branch of the jet stream, in turn, raises the chances for a storm track across the southern and eastern US. As a result, coastal storms will be much more favorable this winter as compared with last year’s La Nina (colder-than-normal) pattern and east coast storms are generally more favorable for snow in places like the big cities of the I-95 corridor - as long as there is sustainable cold air. Second, a “centrally-based” El Nino tends to favor the formation of higher pressure ridging over the western US with a downstream trough over the eastern US and this type of atmospheric pattern usually allows for numerous cold air outbreaks into the central and eastern US. The findings in a recent publication support the idea of an increased chance for a cold and snowy winter in the southern and eastern US during a "centrally-based" El Nino winter season.
Then he goes on to explain about the importance of snowpacks...
Northern Hemisphere snowpack
In addition to oceanic and solar cycles, the snowpack in the Northern Hemisphere during the autumn season is an important consideration for a couple of reasons when preparing a winter outlook. First, a deeper snowpack across the Northern Hemisphere this time of year will likely result in the formation of colder and denser air masses in the important cold air source regions (e.g, Canada, Alaska, Greenland, Siberia). In fact, Greenland has been exceptionally cold since July which is a bullish sign for cold air mass formation. Second, research studies and empirical observations suggest that snowpack in the Northern Hemisphere during the autumn season can be valuable as a predictive tool with respect to “high-latitude blocking” patterns during subsequent winter seasons.
Specifically, research studies (e.g., Dr. Judah Cohen, AER, Inc.) have actually pinpointed the region in Siberia below 60°N during the month of October as critical with respect to the likelihood of “high-latitude blocking” patterns during the following winter season. If snowpack consistently expands during October in that particular part of Siberia, studies have shown that there is an increased chance for more frequent “high-latitude blocking” configurations in subsequent winter months. Indeed, there has been an increase in snowpack in parts of Siberia during the first part of October and computer forecast models suggest there will be additional accumulating snow in that general region in coming days - so far, a neutral to slightly bullish signal for wintertime “high latitude blocking”. The Northern Hemisphere as a whole experienced above-normal snowpack at the end of September ranking it as the 9th highest snow cover extent in the last 50 years and North America had its highest level ever in that same time frame.
Yes Knobby, there is a very strong suggestion (not spoken of here, other than illustrating how things work climate-wise) according to long measures of climate cycles we are heading toward another mini iceage/global cooling which will be somewhat more unpleasant than global warming. Global cooling will cause cloudier skies (bad luck for solar), higher winds colder weather, higher incidents of plagues (more serious influenza outbreaks and so forth), more intense winter conditions, higher risk of drought as the precipitation which is normally falls on the earth will be held in icepacks.
