Update 1/8/15 - Another Strong Arctic Impulse To Make Being Outside & Travel Hazardous Into Tonight!

1/8/15 - Update

As mentioned in last post 

"Other impulses surging southeast in the cold cyclonic flow aloft will bring the risk of light snow or snow showers to the region thru the rest of the week but nothing extraordinary or heavy is expected at this time."

Latest data on another quickly moving Arctic impulse along with strong surface convergence zone over Wisconsin, indicates a band of mainly 1-3" with local amounts near 4" of snow are likely for the region. The snow will begin late this afternoon over western counties and be over much of  Southeast Lower Michigan by sunset. This band of snow will continue into the first half of the night as it plows thru the region rapidly from west to east. Considerable blowing and drifting will accompany the system as a reinforcement of Arctic air moves across the region.

As a result, hazardous travel will be in full force dark along with bitter cold wind chills as low as -15 to -25 with temperatures in the single digits above and below zero! It will be a wicked night outside as dangerously very cold wind chills accompanying the blustery, snowy conditions. Take care if you must go out and/or travel. Because of the relatively uneventful season thus far; this system should be our best (or worst, depending point of view) this season thus far.

1/5/15 - Update

Latest indications have clipper moving faster than discussed back on the 2nd along with a more southern track. While dynamics are adequate for a band of moderate to heavy snow, it will be well south of Southeast Lower Michigan across central and southern Indiana and Ohio tonight into early Tuesday. 

Up here in Southeast Lower Michigan, I would look for little if any snowfall across the Saginaw Valley into the Thumb from the clipper. An inch or less is likely from the Flint to Port Huron areas south into Howell and east across Detroit's northern suburbs. The southern third of the region - roughly from Ann Arbor thru Detroit and points south - will generally see around an inch; possibly two near the Ohio border. Other impulses surging southeast in the cold cyclonic flow aloft will bring the risk of light snow or snow showers to the region thru the rest of the week but nothing extraordinary or heavy is expected at this time.

The big news this week will continue to be the Arctic cold along with a record or near record (for January & depending on locality in the Plains and Midwest) high pressure as it pushes into the Plains and Midwest. After, the high pressure core will weaken with time.  Detroit's barometric high pressure record for January sits at 31.03" /1050.8Mb/ occurring way back in January of 1927. The record of all time is just one hundredth more - 31.04" /1051.1 Mb/ which actually occurred twice; Feb 1934 and March of 1948. All three of these record high pressure readings are safe as the high pressure core will circumnavigate the Great Lakes and weaken.

Temperatures during the week will average well below normal with coldest readings in the single digits to near 10 for highs; while lowest fall into the single digits below zero to possibly as low as -10 to -13 under any intermittent clear skies in the south. Along with the coldest readings expected, another big factor at times will be the dangerously cold wind chills particularly ahead of the Arctic mound of high pressure Wednesday into Thursday.

Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian


Original 1/2/15 -

In my last blog, I spoke of the weekend potential snowstorm's demise and issued the likely unfolding scenario of the system yesterday, New Year's Day.

" Here we are again with a storm taking aim on the Great Lakes - and here we are again -  likely to miss a significant snowfall. Why? The decided storm track will likely again be anti-climatic for Southeast Lower Michigan to experience a big storm. Latest indications are the low pressure will begin developing over eastern Texas, slide north northeast thru Western Arkansas, Missouri, southern Illinois and on northward across northwest Indiana into southwest Lower Michigan. From there, best track at this time appears to be over or near Battle Creek, Lansing and Saginaw then out over Lake Huron while she deepens. 

Does this mean all chances snow or even mixed precipitation have gone by the wayside? No. As the low approaches and pushes the warmer, moisture laden air over the cold air and landscape I look for a mix of snow, sleet and freezing rain to overspread Southeast Lower Michigan during the day Saturday; changing over the rain across the region by Saturday night then back to snow and snowshowers overnight. The best chance for any accumulations of snow will be again, like the last storm, over the Saginaw Valley at the onset and behind the system."

This system still looks too warm to bring any large amounts of snow to the region. That being said; the latest storm track is a bit further southeast and closer to my original thinking; east northeast across the Tri-state area of Indiana/Ohio/Michigan then onward over the southeast corner of Lower Michigan and into southwest Ontario. This southeast shift of track almost guarantees a period of mixed precipitation across Southeast Lower Michigan along with some snow accumulations at the onset and behind the system (as mentioned yesterday). 

While precipitation will begin as snow, sleet and/or freezing rain; any snow accumulations will be minor in the southern areas (Ann Arbor - Metro Detroit - Adrian - Monroe areas) mainly amounting to an inch or less. The bigger headache will be traveling during the morning and early afternoon hours everywhere where the combination of mixed precipitation and cold ground makes driving hazardous until temperatures climb above freezing. Further north into the Howell - Pontiac - Flint - Port Huron areas a couple inches of snow mixed with sleet and freezing rain may get a chance to accumulate an inch or two before the change to rain. Again the furthest north-northwest areas, into the Saginaw Valley and Thumb Region could see 2-3" of snow, sleet and freezing rain before mixing and changing 

to rain.

Impressive Strong Cold Air Advection Will Bring Coldest Air of the Season and Dangerous Wind Chills into Early Next Week !

Strong Arctic high pressures surging out of Canada this next week will bring impressive cold air advection and pressure gradients due to the high pressure cores. Central estimate pressure readings at this time of 1045 - 1057 MB /30.85 - 31.20 IN/ are expected to flood into the country. These strong high pressure readings and the tight gradients of cold air advection will bring dangerous low wind chills in the upcoming week; at times well below zero! Air temperatures of teens and single figures are likely much of the time, however coldest lows could fall below zero on some morning.

Take a look at this neat animation of the Polar Vortex split and Arctic conveyor belt from the North Pole vantage affecting the upcoming system for this week.

Potent Clipper to Bring a Round of Snow and Wind Tuesday into Tuesday Night

A fast moving Alberta Clipper should push an area of snow across the upper Midwest into the Great Lakes and Ohio Valley, Tuesday into Tuesday night. While this system will be quickly moving and somewhat limited in moisture, it will deposit a swath of measurable snow across all or parts of the region.  I say somewhat limited on moisture because as a rule, these storm systems tend to be on the drier side. Early indications however, do show encouraging moisture amounts and snowfalls of possibly generally 1-3"or even 2-4". This is EARLY, so you know the scoop; don't count on those amounts until you see the definite track, moisture and whites of the flakes! ;-) You know how Mom Nature's been cheap with the snow this season as opposed to last! In any event; it WILL BE COLD this week!

While winter's been stubborn to take residence over the country and Great Lakes this cold season; this week should let everyone know what season it is!

Updates likely this upcoming week!

Have a Happy, Healthy and Prosperous New Year for 2015!

Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian

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