Tricky Halloween Forecast | NECN
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Meteorologists' Observations on the Weather

Tricky Halloween Forecast

New England may be treated to snow in late October or early November.



    A rough estimate of where snow will fall between Sunday, Oct. 26 and Sunday, Nov. 2. It's an extreme pattern, so this could be conservative.

    After one of the driest Septembers on record in New England, October has made up for the deficit, and then some.

    The Blue Hill Weather Observatory has recorded almost 10 inches of rainfall so far, more than twice the normal for October.

    During September, we saw a blocking pattern with all the storm missing to our south, west and east.

    Now, in October, we have a bit less of a blocking pattern, but a high amplitude flow in the jet stream continues. The difference is that now, we have the rain storms stalling in the eastern and northeastern U.S.

    Each of the heaviest storms have featured tropical air running up from the Bahamas and into Polar high pressure over southeastern Canada. This set up produces the heaviest possible precipitation for us (tropical energy is expelled by the tropics whether or not there are named storms). Also, the track of the low pressure to our south, with high pressure to our north, is exactly the configuration that produces now in winter months.

    Now, for the third time since Oct. 1, we may see a similar situation for Halloween night and next weekend.

    One ingredient of our potential Halloween trick is something I do not recall ever observing in a New England snowstorm.

    Former Hurricane Ana in the North Pacific Ocean may track all the way to the Gulf of Maine, via Canada.

    The long, strange trip of Pacific Tropical Cyclone Ana. Now Post-Tropical Cyclone Ana is forecast into British Columbia Canada Wednesday, Oct 29.

    Another ingredient of our potential Halloween treat is air from Siberia, where early autumn snowfall is setting records for depth and expanse.

    This is a sign that we have a special (extra snowy and cold) winter setting up.

    This arctic airmass is forecast to move in unison, just to the north of, Ana's remnant across western Canada mid week. These two weather ingredients are rather extreme in nature given the season.

    When witnessing weather extremes, one looks for the balance. For example, Pacific storms are soaking the northwestern U.S. and Canada, as California is parched dry.

    The cold in Alaska is balanced by heat in the U.S. plains. Oklahoma City is having its latest 90-degree day on record. A very dry September in New England will be balanced by soaking October storms.

    Much of it has do with how long waves patterns set up. For the last four weeks, the upper level roughs have set up near New England, and that appears to be happening again for our first weekend in November.

    With confidence level of medium-to-low, here is a rough estimate of where snow will fall before next Sunday:

    A rough estimate of where snow will fall between Sunday, Oct. 26 and Sunday, Nov. 2. It's an extreme pattern, so this could be conservative.

    This may be the third system in four weeks that would have been the right set up for double digit snowfall during winter. 

    Just saying.

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