*Update - Sunday - 11/22/2015 - Snowstorm Epilogue Over Southeast Lower Michigan

Sunday  - 11/22/2015 - Snowstorm Epilogue

As many years as I've been involved with weather; still occasionally a storm comes along that surprises me or takes me back, reminding me of another. This storm was not only an over-achiever; it had a tricky snowfall forecast placement due to all the things mentioned in the previous posts.

Probably the most surprising item about the storm was the amazing snow depths that focused on the expected heaviest snow area (in the center of Southeast Lower Michigan). In every forecast I observed, I didn't see anyone forecasting 12-16" of snow, even in last forecast period before the storm's arrival- with notably less amounts in the days leading up to the storm. It goes to show you how even with as much meteorological science as we have, the last say will always be Mom Nature! And that my friends; is why I'm still a weather-enthusiast spelled.... N U T.... the unpredictable excitement that still happens.

Observing snowfall rates personally during the storm and seeing video in the worst (or best, depending point of view) snowfall regions with the huge, continuous snowflakes and near zero visibilites for hours as temperatures hovered near freezing. This reminded me somewhat of the first monster I observed many years ago in my infancy with the NWS - see: The Thanksgiving Weekend Snowstorm of December 1st, 1974 in which the 40th anniversary was just reached last year. The storms were different as far as synoptic pattern and max snowfalls but similar as far as personal visual observance, snowfall patterns with its sharp highest snowfall amounts over Southeast Lower Michigan and ironically, also occurring near Thanksgiving (the weekend before rather than the weekend after). Even the storm hour timing was similar; starting near dawn in some areas and lasting into part of the night. The heaviest being the mid-late morning into the early evening

The present day storm only approached max snowfalls in a small area seen back in 1974 (with the core being further north yesterday) since   in 1974, the heart of the heaviest core was further south from Jackson to Detroit with Detroit Metro /DTW/ recording 19.3", which was pretty much the highest over the area (though much of immediate Detroit area saw similar amounts). The '74 storm also contained more wind overall causing more substantial drifting. I worked that storm and to this day, nothing has equaled it for me as far as long continuous large snowflake rates nor snowfall amounts over the Detroit Metro area. Those who remember the 1974 storm and now live up in this recent heaviest snow areas might also have some comparative memories. BTW - The Blizzard of '78 was a much larger, widespread super snowstorm in more ways than the '74 and I also worked and wrote about here, BUT snowfalls were less over the metro Detroit area than in 1974.

Here is a nice summary of November 21st 2015 Snowstorm from the NWS in White Lake, who also keep forecasters on their toes! It was the largest snowfall recorded at the office /DTX/ since the office was built in 1994  

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

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Sat - 11/21/15 Update 

Very interesting storm in progress as far as snowfall rates and sharp delineation of visibilites and accumulations. Look for quite a range of intensities over the extreme southeast corner of lower Michigan through the afternoon and early evening - where the sharpest change of snowfall accumulations will occur. This mainly runs from the immediate Detroit area, southeast to the Ohio border (see map). Otherwise; boosted snowfall amounts somewhat in the best snowfall area to account for heavier band of snow projected this afternoon into early evening. Of course, the best snow amounts will be on grassy areas along with some settling/melting. ENJOY!

As discussed below; 

Snowfall positives for highest snowfalls include system's more southern track, upper energy and available moisture. Negatives include atmospheric low level temperatures mainly in the lower to mid 30s through the afternoon, possible period of snow mixed with rain over the extreme southeast corner of Lower Michigan and of course, some melting due to the relatively warm ground.
 


*Fri - 11/20/15 Update

STORM CENTER NOW EXPECTED TO TRACK FURTHER SOUTH, DROPPING THE AREA OF HEAVIEST SNOW SOUTH ALONG WITH IT OVER SOUTHEAST MICHIGAN

Latest guidance from last night continues the trend of dropping the track of the low pressure south into the the northern Ohio Valley. Earlier consensus tracks brought the low to the Michigan/Ohio border. Better sampling of the phasing of the two areas of energy spoke about at the onset now suggests the further south track.

With that in mind and looking at the latest surface and upper air data; snowfall projections (+/- an inch) are being updated in accord with latest information.  

 SNOWFALLS

As discussed below; 

Snowfall positives for highest snowfalls include system's more southern track, upper energy and available moisture. Negatives include atmospheric low level temperatures in the lower to mid 30s, possible period of snow mixed with rain mainly at the onset over the extreme southeast corner of Lower Michigan and of course, some melting due to the relatively warm ground.



*Thu - 11/19/15 Update 


No major changes from yesterday as current modeling continues projection of the development and progression of the low pressure responsible for snow potential. At this time, it appears the low will track across extreme Northwest Ohio/extreme Southeast Lower Michigan region. I stated below a snowfalls of a Trace to around 4" across Southeast Lower Michigan for the system and that still is close to my analysis possible higher amounts in the Saginaw Valley. That being said, I can narrow down the particulars:

Pattern:
Snow should begin Friday overnight into Saturday and diminish off to flurries Saturday night. The snow should mix with rain over the far southeast corner of lower Michigan.Temperatures should hover mainly in the 30s through much of the snowfall.

Snowfall Estimate Map (give or take an inch)

Snowfall positives for highest snowfalls include system's track, upper energy and available moisture. Negatives include atmospheric low level temperatures and possible mix with rain.

Look for updates if needed.


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Original - 11/18/15

In my Winter Outlook issued last weekend, I discussed the upper wind pattern getting charged up under the Fight Has Just Begun paragraph:

The Fight Has Just Begun!

While El Nino has been strong over the Pacific, its downwind affects for the most part, have yet to be seen much in our neck of the woods. We've had a relatively beautiful, warm fall thus far - somewhat uncharacteristic of strong El Nino's (dependent on El Nino strength and timing) which tend to be cooler, see Autumn Outlook analogues. During the strong El Nino's of 1982-83 and 1997-98 the atmospheric characteristics and downwind affects really didn't peak until the winter period. Thus far, along the central and southern West Coast, the "wave-train" of storms has yet to materialize but if history is any indicator, next month should see things pick up some. Things have begun to change here in November though with some storms tracking further south into the West Coast, deepening on the lee side of the mountains and heading into the Great Lakes. However, this pattern is really not unusual for any late fall period so, nothing too El Nino-like.

At the same time; the Polar/Arctic jet has shown signs of expanding and phasing further south into the sub-tropical jet, typical for November. While the subtropical jet is becoming more active, so is the Polar/Arctic jet. This has created a combative, progressive rolling jet pattern across the country. I look for this pattern to continue into at least into early December as timing is always an issue this far out. 

This upcoming weekend we have a fine example of discussed phasing of the Polar Jet and the Pacific jet energy over the western portion of the country and trekking east across the Plains, Midwest and Great Lakes/Ohio Valley. This mixed/phased system should brew a low pressure over the Midwest into the Great Lakes. 

Depending on the exact track of the low, along with lower atmosphere/surface temperatures and ground temperatures will determine the exact amounts of snow/rain accumulation. She's not even on the map yet but her "parents" are so let's take a look at this "mating" of weather systems. Realistic snowfalls depending on existing conditions at the time could range from a trace to potentially as much as 4" across portions of Southeast Lower Michigan since this system hasn't even formed yet. Let's give it time to get better sampled and tracked.

 Updates as development and track becomes more apparent.

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