Saturday, January 24, 2015


Originally prepared: January 14-15, 2015 (Facebook timeline-post) 
A further in-depth look at the 2014/15 Winter Season! Well, changes are... and certainly have occurred. The image below (although-not-current) depicts - MAJOR - changes that have occurred with the 500-millibar Height Pattern over North America (and the Northern Hemisphere as-a-whole). What has happened? The most noteworthy change from December is-with-the Polar Vortex (PV), itself. The polar vortex is an intense (cold) upper-level low pressure system that originates over the Arctic / North Pole, and this-is-where the PV stayed for most of December. However, through poleward stratospheric changes "warming"... the PV SPLIT into two (2) separate lobes and dropped south, with one lobe falling over North America, and the other over Eurasia. Through these changes, the pole moderates... as "Blocking High Pressure" becomes established across northern latitudes (i.e. Arctic Oscillation "AO" becomes increasingly negative), ejecting the upper-level low pressure system from the Gulf of Alaska & replacing-it with intensifying High Pressure (notice the greenish shade toward the Gulf of Alaska on-the-image, indicating moderating anomalies, which is a significant change from December). It's very IMPORTANT to understand that during most of-the-classic old fashioned winter's experienced in New England during the 1950's, 60's, & 70's the PV almost always split... if this doesn't take place, you end-up with a longwave weather pattern similar to-that-of December 2014, "progressive", which was experienced through most-of-the absent winter's of-the-1990's! Now that the PV has split, what will happen? The 500-millibar Height Pattern is-open to configure itself to repeat the 1950's, 60's, & 70's all-over-again... and will attempt to do just that on-or-about January 21st, before this time frame there will be a temporary moderation... indicating CHANGE. What does this mean? We have now certainly experienced the "cold" but have yet to combine that with true snowstorms (Nor'easters)... on-or-about this date (1/21) is when all-the-elements have the potential to-come-together (i.e. North Atlantic Oscillation "NAO" also becomes negative), thus "blocking" / lifting the jet-stream up along the U.S. Eastern seaboard, promoting East coast cyclogenesis. This change will make run at balancing the December blowtorch, as January 2015 should average "at least" 1-2° below normal in-temperature, however beyond this... with the exception of a brief mild spell around the second week-of-February, both February & March 2015 have a strong probability of averaging below normal in-temperature, considering the above-said-factors. In closing, the Winter Season of 2014/15 has strong potential of averaging slightly below normal in-temperature overall, with above normal snowfall through much-of-New England. What is average snowfall? For example: ADAMS / NORTH ADAMS - 78.1" average annual snowfall. Winter 2014/15: potential 100.0"+ for-the-season as-a-whole. BOSTON - around 43.0" average annual snowfall. Winter 2014/15: potential 50.0"+ for-the-season as-a-whole.