I'm a CMU Honors student and love meteorology and extreme weather. I've been fascinated by weather since I was 5, and plan on becoming a meteorologist
By: wxchaser97 , 3:34 PM GMT on November 21, 2012
2012-2013 Winter Forecast
Review of 2011-2012 winter:
The 2011-2012 winter started off at a fast pace. A big snowstorm slammed the Northeast around the Halloween time period. This area was already hit hard from Hurricane Irene and Tropical storm Lee from earlier in the year. The trees, utility poles, and homes that weren't damaged by the tropical cyclones got hit from the snow. Heavy wet snow fell on parts of the NE which caused lots of damage and even a few deaths. This system was nicknamed "snowtober" due to its proximity with Halloween. This snowstorm was the biggest and most memorable storm of the winter season. Besides some other smaller early season storms that occurred in the north not much major would happen. A positve NAO would take over as the winter progressed on. Even though we were in a La Nina pattern it felt more like El Nino. The Greenland Blocking High/ridge wasn't in place for a long time during last winter as well. This lead to drier and warmer conditions in the northern half of the country. Record minimum snowfall fell in some areas that had record maximum snow the year before. This would set the stage for a drought of record proportions across parts of the country.
Factors for 2012-2013:
This winter will feature some changes from the last. The ENSO should be in a more neutral state. This has been backed up by the discontinuation of El Nino watch and the SST's not warming too high. The trade winds are in an average flow and speed and there isn't any strong Kelvin cycles in the area that could trigger an El Nino episode. The NAO, AO, and Greenland ridge are harder to predict past a couple weeks. If the ridge can set up and NAO goes more negative and AO more positive there would be more snow and cold. Less blocking and a more positive NAO would result in less snow and warmer temps. Also the snow pack in the far north can impact winter. Depending on if there is normal or above/below average snow pack can show how much cold air is in the arctic. More snow would show more cold air and there would be more to flow down to the CONUS. Right now far northern snow pack is near average. The Great Lakes will affect winter in that area. Warmer and less frozen waters would allow more lake-effect snow if the cold air is there. If the lakes freeze earlier then less lake-effect can happen. This is another factor that is too far out in the future to predict well.
Winter Forecast and graphic:
The 2012-2013 winter should be snowier and colder than last winter. I am thinking there will be a good amount of cold shots in the Great Lakes and Mid West this year. The cold air will be accompanied by an active clipper system pattern. I think near to slightly above normal snowfall can be expected and normal to below normal temperatures can be expected here. The Northeast should continue to see the occasional coastal storm. These would bring some rain, wind, and snow depending on where you are and how close the low is to the coast. They won't be as cold near the coast but I expect near normal to maybe slightly above normal if a bigger Nor'easter rolls in. The Mid Atlantic and Ohio Valley will be the battle zone of cold air and mild air. If the NAO stays mostly negative then there should be more snow and cold air. If the NAO is more positive then expect more mild spells and less snow. I think there could be average, maybe below, temps and near, maybe slightly above, average snowfall. The south should have rain and cooler temps. The Tenn, NC, and surrounding areas should see mixed precip at times. Could be some ice storms if there is the right ingredients. Severe weather will become a threat in the latter part of winter. The southern plains and mountain west should have above average temperatures. Precipitation chances are around average for the winter months. The California coast should have below normal precip and average temps. The NW should have normal temps and above normal precip. All in all, a near normal winter should be expected.
Have a great couple days and I will be back with either a breaking weather update or my first tropical cyclone summary.
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