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Update 2/7 Thursday Early Afternoon...
Little change from earlier thinking across Southeast Lower Michigan on system as it moves into the region. Snow will overspread the northern half of Southeast Lower Michigan first later this afternoon and gradually overspread extreme Southeast Michigan (Metro Detroit and points south) later tonight.
One trend and change that has been noted; milder air has crept into the southern part of the system and with that, comes the likelihood of mixed precipitation. Look for snow, sleet and some freezing rain possible during the initial hours of the precipitation, especially from I-69 southward.This will cut snow totals back somewhat if lasts for any length of time. Total snowfalls of around 2 - 4" are likely over the extreme south (below I-94) with 3 - 7" over much of the rest of the region including Ann Arbor...Detroit and northern suburbs. Higher amounts of 6" to as much as 9" are likely mainly north of I-69 up into the Saginaw Valley and Thumb Region including the Thumb region.
Update 2/6 Wednesday Early Afternoon...
The strongest of the clippers mentioned in the previous article will come through Southeast Lower Michigan later Thursday into Friday morning. The low pressure system will develop stronger than first projected as it gets aid from the south in the form of energy and moisture as the storm center taps a "phasing jet" (two jet streams/streaks combining and intensifying the surface system; see Maps - 1/2). This is a very recent development (in the past day or so) as our models get a better handle on energy diving in from Canada and also from the Southwest; therefore look for more snowfall from this system. Total snowfalls of around 3 - 7" are now possible with this Clipper across much of Southeast Lower Michigan (least near the Ohio border) with higher amounts of 6" to as much as 10" mainly north of I-69 up into the Saginaw Valley and Thumb Region. Early indications are as the storm moves east of the Lakes (Maps - 3/4); even more phasing is projected to occur with an impulse moving along the south and then up along the East Coast. Several models at this time are projecting a rapidly intensifying Northeaster' (Maps - 5/6) for the Northeast Friday into Saturday as a large Ridge of high pressure settles over the Great Lakes. This is one of the classic ways a Northeaster' forms from a Clipper system. It will be interesting to see how the models do on this storm development! Expect updates on this storm are she develops the next 12-48 hours.
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| Making weather fun while we all learn, Bill Deedler -SEMI_WeatherHistorian |
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2/5/12
Yes; we are in the midst of "clipperville" this week across the Great Lakes and Southeast Lower Michigan. What is clipperville? It's just a word I made up on account of all the weak clipper type low pressure systems transversing the Great Lakes this week. Another question you might ask? What is a clipper low pressure system? Or more exact; an Alberta Clipper type of low pressure system? A Saskatchewan Screamer? A Manitoba Mauler? But I digress...
These are all specific names officially (or non-officially) given to quickly moving lower pressure systems that commonly develop along a Polar or Arctic air mass front; forming, as their name implies, over a particular geographical area in southwest or south-central Canada whether it be Alberta, Saskatchewan or Manitoba. They create one of the most dominant storm tracks seen during the winter months that may affect the weather from the Northern Plains clear on through the Upper Mississippi Valley, Midwest, Great Lakes, Ohio Valley all the way to the Mid Atlantic and Northeast. Their tracks vary somewhat depending on intensity and upper air support but they all have one thing in common; they're on the move, trekking rapidly east southeast (frequently at 35 to 45 mph). The well developed clipper can also contain strong gusty winds of 35 to around 45 mph. The word "clipper" comes from an old 19th century seaman's term for the clipper sailing ships of the time because of their quick speeds in strong winds. A more elaborate discussion on clippers can be found here.
The National Weather Services official definition is as follows;
- Alberta Clipper
- A fast moving low pressure system that moves southeast out of Canadian Province of Alberta (southwest Canada) through the Plains, Midwest, and Great Lakes region usually during the winter. This low pressure area is usually accompanied by light snow, strong winds, and colder temperatures. Another variation of the same system is called a "Saskatchewan Screamer".
- Source: NOAA
- The most memorable clipper I can recall was a clipper we termed at the DTX NWS office as Super-Clipper! I had never seen such a widespread heavy snowfall with any other clipper that clipped Southeast Michigan, like the Super-Clipper of January 22-23, 2005 while in the NWS.
- From my 2005 Annual write-up for January 2005;
A strong Alberta clipper clobbered the area with generally 8" to 14" of snow on January 22nd-23rd. Officially at Detroit Metro Airport, 12.2" of snow fell on the 22nd. That amount placed the storm in at 11th place for biggest snowstorm at that time. - Relax though; none of the clippers clipping us this week will be near as strong as Super-Clipper; a more appropriate term for these guys would be "snippers". ;-)
Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian
