Updraft: February 9, 2010 Archive

Unusual winter storm winds down

Posted at 8:35 AM on February 9, 2010 by Paul Huttner

Our latest winter storm was unusual in many ways.

-The track of the upper low pressure system was almost directly north to south. The parent upper low tracked from near Winnipeg straight south along I-29 to near Sioux Falls Monday. This is almost the opposite of our more common Alberta Clippers (NW to SE) or our Panhandle Hook or Gulf Storms (SW to NE).

-The duration of continuous snowfall was much longer than most of our winter storms. Through 8am local time today, we've recorded 42 continuous hours of snowfall at Twin Cities Airport. An "average" winter storm might produce between 12 and 18 hours of continuous snow. The slow moving nature of this storm caused the long duration snowfall event.

Even with the long snow, it is nowhere near a record. The record for continuous snowfall in the Twin Cities is 88 hours; from December 6th to December 9th, 1969. That storm produced 14" in the Twin Cities.

-Snowfall intensities remained light during much of the storm. There were only a few hours of moderate intensity snow. This is why snowfall totals were not even higher given the long duration of snowfall. Even so, snowfall totals across the metro ranged from 4.5" (NE metro) to 10.5" (SW metro) which is a respectable storm.

NWS snowfall total map shows heaviest bands favored areas west and south of the metro. Note the odd "kink" in the snowfall near Twin Cities Airport, which recorded one of the lowest totals in the storm, (5.5" two-day total) even though much higher totals were recorded in all directions from the airport.

-A compact arctic air pocket moved with the storm right under the center of the cold core low. Temperatures briefly plunged below zero in a relatively small area in southeast South Dakota and southwest Minnesota last night. It was -6 in Pipestone and -11 in Sioux Falls before temperatures actually rebounded overnight to above zero readings.

This is almost opposite of what we usually see, with arctic air following behind winter storms.

The storm pulls out today, and sunshine returns tomorrow. The good news is, our next chance of snow will not arrive until Saturday!

PH

Storm rolls east

Posted at 4:30 PM on February 9, 2010 by Paul Huttner (1 Comments)

Winter storm warnings stretch from Iowa to the east coast Tuesday afternoon.

Our 45 hour marathon winter storm is in the books for Minnesota, but the rampage continues. As many as 18 states are under winter storm warnings late Tuesday as the impressive and long lasting storm rolls east.

Snowfall totals of one foot or more are forecast or occurring from Chicago to Washington D.C. as the system cranks out more snow. This is truly becoming the winter of discontent for many in the USA.

This storm has an interesting and rather unusual path. It tracked south from the Arctic Circle into the eastern Dakotas before swinging east into southern Illinois on the trip to the east coast.

It may surprise many to know that storms can travel thousands of miles and maintain the parent circulation. There have been documented instances of Mongolian dust storms completely circling the globe in 9 days. In 1966 Hurricane Faith crossed the Atlantic twice and moved from he tropics to nearly the north pole. Faith has the longest documented path of any hurricane on record.

Track of Hurricane Faith in 1966.

In the Pacific Hurricane John lasted an incredible 31 days as a tropical cyclone.

Hurricane John in 1994.

As our neighbors to the east dig out, we can be thankful for a break in the snowfall. And we can also hope the same storm doesn't circle the big upper low over northeast Canada and hit us again in a week or so.

PH

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