3/3/13

Update 3/5/13 - New Week; New Storm?

Update 3/5/13...
Looking at model, radar and satellite trends of the snow occurring to the west and south of the region as of noon; the storm will remain south of Southeast Lower Michigan. While there may be flurries or a dusting near the Ohio border, no appreciable accumulation is expected. So ends the chapter on the "storm that couldn't - in Southeast Lower Michigan".

Update 3/4/13...
Latest guidance has now reverted back to the original, further south track of the projected storm along with much of its significant snow. In the discussion yesterday; I mentioned the risk of this happening since the models earlier tracks were further south and the northward track, a recent development.

"there is still quite a variance of storm tracks possible with this system and it is possible Southeast Lower Michigan misses the brunt of the storm IF she forms or dives further southeast. This further southeast projection WAS the original track on this storm just a few days ago, so nothing is for certain but know this; the track has been lifting northward recently."

Though the original, further south track looked reasonable to me earlier, I decided I needed to give a heads up about the potential of the storm yesterday considering; 1- the recent northward shift of the action; especially relying on "better data" ingested into the models for the latest period and 2- the snow risk of rather significant snow amounts (several inches) over the far southern half of the region.

Consensus data from the latest Monday morning runs; shows not only having the further south track re-appearing but the latest cut-off line of snow and no snow remains unusually sharp, leaving much of Southeast Lower Michigan with no snow. Yesterday's thinking as far as where the risk of snow was - over the southern half of the region - therefore can be trimmed back further.

Snowfall is still possible over the far four southern counties of Southeast Lower Michigan... Washtenaw...Wayne...Lenawee and Monroe. The best snowfall of an inch or two would be over Lenawee and Monroe counties with up to around an inch in Washtenaw and Wayne. Respecting the sharp cut-off with the snowfall pattern; the northern portions of Washtenaw and Wayne should receive the least. Timing will be mainly overnight Tuesday into Wednesday morning.

This continues to be a very difficult forecast because any oscillation of 50 miles or so would be the difference of no snow and a few inches. Therefore; stay tuned, "cause the fun continues!"

Note; Meteorologist Hally Vogel from ABC's Channel -7 Detroit Action News team interviewed me recently on two of our biggest snowstorms in modern times to hit the Metro Detroit area and/or Southeast Lower Michigan. One storm being the Dec 1st, 1974 storm and the other; the Great Blizzard of January 1978. I worked both storms and relayed my experiences and subsequent outcomes of those two very memorable storms early in my career in these write-ups and interview. As of this time; the short piece is set to air Wednesday March 6th, during the 5 pm weather segment (around 515 PM) with other weather interview segments possible in the future. Any changes I will update.
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Original Blog 3/4/13...
Over the past day or so, guidance has been coming together of a new storm brewing over the Northern Plains while another takes shape over the Texas Panhandle (map -1). Our guidance seems to want to "mate" or phase these storms over the Ohio Valley with time, by forming a signification storm  across the Ohio Valley in the vicinity of Indiana, Ohio and Kentucky (with the center of the combining lows near Cincinnati (map -2). How well developed she is at that time along with moisture and ultimate track will dictate the final outcome of the snow potential for Southeast Lower Michigan.

Of all the data coming in on this storm; perhaps the most consistent is timing and ironically thus far; it's almost a duplicate of last week's storm.  Consensus is for the storm to begin to affect Southeast Lower Michigan during the afternoon hours of Tuesday into Tuesday night and Wednesday morning. Sound familiar?

There is the potential for this storm to bring a significant amount of snow to at least portions of Southeast Lower Michigan and at this time the best chances appears to be the southern half of the region. If this were to bear out; the areas most affected would include the cities and surrounding communities of Ann Arbor into the suburbs of Detroit and the city of Detroit; southward to the Ohio border. Of course, this is all very preliminary and subject to change as sampling improves on this potential developing storm. Basically; the timing of the two systems along with their interaction will tell the story. The next few model runs should get a better handle on data. In addition; a sharp cut-off of the snowfall extent to the north was noted across Southeast Lower Michigan.

While the forecasted dynamics and moisture available for this storm has been improving with each model(s) runs; there is still quite a variance of storm tracks possible with this system and it is possible Southeast Lower Michigan misses the brunt of the storm IF she forms or dives further southeast. This further southeast projection WAS the original track on this storm just a few days ago, so nothing is for certain but know this; the track has been lifting northward recently. See the latest track below /GFS/ (note; the Euro was not in as of this post but all  referred to were the NAM, GFS, UKMET & GEM):



Stay Tuned for further updates on this rather recent development.

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