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

Update 2/27/13 - Feb 26-27, 2013 Snow Totals

Epilogue;
Snowstorm Totals From the NWS DTX

Feb 26-27, 2013 Snow Totals

A strong low pressure system originating near Texas tracked northeast into the Ohio Valley. This storm induced blizzard, winter storm, and tornado headlines as it tracked through the US. As the low lifted north, a mix of rain, freezing rain, sleet, and snow commenced Tuesday afternoon. A changeover to snow began near 4-7pm for most areas. A general 3-5" swath of snow fell across most of Southeast Michigan. Text and graphic summaries are available below. Snowfall totals through 10 am February 27th, 2013, are available in graphic and text formats.

PUBLIC INFORMATION STATEMENT...STORM TOTALS

NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI

1016 AM EST WED FEB 27 2013

 

STORM TOTAL SNOW REPORTS

LOCATION                  SNOWFALL     DURATION

                          (INCHES)      (HOURS)        LAT       LON

...BAY COUNTY...

   AUBURN                  M   2.6           12     43.60N    84.08W

...GENESEE COUNTY...

   BURTON                  M   2.2           14     43.00N    83.62W

   FLINT                   M   2.8           14     43.02N    83.69W

   LINDEN                  M   3.0           14     42.82N    83.78W

...HURON COUNTY...

   FILION                  M   0.6           12     43.90N    83.00W

   BAD AXE                 M   3.2           11     43.80N    83.00W

...LAPEER COUNTY...

   LAPEER                  M   4.2           14     43.05N    83.32W

   LUM                     M   5.1           15     43.10N    83.15W

   NORTH BRANCH            M   5.4           14     43.23N    83.19W

...LENAWEE COUNTY...

   ADRIAN                  M   3.0           12     41.90N    84.04W

   TIPTON                  M   6.0           14     42.02N    84.06W

...LIVINGSTON COUNTY...

   HOWELL                  M   2.0           13     42.61N    83.94W

...MACOMB COUNTY...

   STERLING HEIGHTS        M   3.0           13     42.58N    83.03W

   MOUNT CLEMENS           M   5.5            8     42.60N    82.88W

...MONROE COUNTY...

   MONROE                  M   0.8            M     41.92N    83.39W

   DUNDEE                  M   3.7           14     41.96N    83.66W

...OAKLAND COUNTY...

   HOLLY                   M   2.8           14     42.80N    83.62W

   2 N NOVI                M   4.0           12     42.50N    83.49W

   BLOOMFIELD HILLS        M   4.0           14     42.58N    83.25W

   CLARKSTON               M   4.0           14     42.74N    83.42W

   SOUTHFIELD              M   4.0           12     42.48N    83.26W

   FARMINGTON HILLS        M   4.3           14     42.49N    83.38W

   WHITE LAKE              M   4.5           14     42.65N    83.50W

...SAGINAW COUNTY...

   5 S MERRILL             M   4.0           13     43.34N    84.34W

   FREELAND                M   4.5           13     43.52N    84.12W

   HEMLOCK                 M   6.5           14     43.42N    84.23W

...SANILAC COUNTY...

   DECKERVILLE             M   5.0           12     43.53N    82.74W

   LEXINGTON               M   5.0           13     43.27N    82.53W

   SANDUSKY                M   5.0           13     43.42N    82.83W

...SHIAWASSEE COUNTY...

   CORUNNA                 M   3.0           12     42.98N    84.12W

   OWOSSO                  M   3.7           14     43.00N    84.18W

...ST. CLAIR COUNTY...

   YALE                    M   4.5           13     43.13N    82.80W

...TUSCOLA COUNTY...

   FAIRGROVE               M   2.0           12     43.52N    83.54W

   VASSAR                  M   2.6           14     43.37N    83.58W

   CARO                    M   3.0           12     43.49N    83.40W

...WASHTENAW COUNTY...

   SALINE                  M   3.6           14     42.18N    83.78W

   MANCHESTER              M   4.0           14     42.15N    84.04W

   5 SE ANN ARBOR          M   5.0           13     42.22N    83.66W

   CHELSEA                 M   5.0           14     42.31N    84.02W

   1 W ANN ARBOR           M   5.5           14     42.28N    83.75W

   DEXTER                  M   6.8           14     42.33N    83.88W

   1 S ANN ARBOR           M   7.0           14     42.26N    83.73W

...WAYNE COUNTY...

   GROSSE POINTE FARMS     M   2.4           14     42.40N    82.89W

   ROMULUS                 M   3.0           14     42.22N    83.37W

M = MEASURED

E = ESTIMATED

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Update 2/26/13...100 PM

Mixed precipitation will advance across Southeast Lower Michigan during the afternoon quicker than initially anticipated...therefore a longer period of rain...snow...sleet and freezing rain will occur into at least early evening. Because of more mixed precipitation; snowfall amounts will be impacted, especially over extreme Southeast Lower Michigan. Latest guidance /12z - 7AM/ continues to wrap in pockets of milder (above freezing air) into the storm into the evening anyway. This was the risk noted in earlier forecasts below and thus, snowfalls have been adjusted lower.

Snowfalls across extreme Southeast Lower Michigan from I-94 south to the Ohio border will be impacted the most with generally 1" - 3" likely. The remaining area of Southeast Lower Michigan;  Detroit, Detroit's northwest-northeast suburbs, Ann Arbor, Flint, Saginaw Valley and Port Huron amounts will vary from 2" - 3" over the extreme southern regions to 3" - 5" across the majority of the region into the northern areas. Best snowfalls will remain over the northeast counties including the Thumb where 4" - 6" is expected to accumulate. Stiff northeast winds will gradually shift to north at 15 to 25 mph with gusts around 30 mph into tonight before diminishing.

Update 2/25/13...

Snowfalls
Generally I look for a 4" - 7" total of heavy wet snow over much of region from this system through  Wednesday - with much of that snow falling late Tuesday into midday Wednesday. Eastern counties, especially downwind of Lake Huron may see highest with isolated 8" or so possible.  I will update if the system information changes going into the event.

Discussion
Overall very little has changed on our expected winter storm the past few days as most models continue to prog the storm in the track first outlined in the original blog 2/23. In fact; the major models are in remarkable agreement as to the general track of the low center with a subtle shift southward of both the 500H MB and surface low in the last 12-24 runs.

The European continues this lead (I originally chose in the initial blog below) with now both the GFS and the European pretty well in step. Of course; the devil is in the details...and in this case the problems lie in precipitation amounts and how much "warm air" gets entrained into the lower levels of the atmosphere. While this system somewhat resembles our Dec 26th storm it is much further north and thus; milder but at the same time the dynamics of the system are more impressive overhead as is its moisture feed from initially the Gulf and subsequently Atlantic.

The system has well developed features aloft including; a compact negative tilt structure that consolidates into a "bowling ball" shape that "hooks" for the Ohio pocket as she heads northeast. Meanwhile; the surface system along with the 700MB low follow along in good measure right into Southeast Lower Michigan and Northwest Ohio. And old rule of thumb with the 700 MB; to the left of center, generally the best snow can be expected in a mature system. And, while our storm is projected to weaken with time as she treks toward the Eastern Lakes; she still maintains a moderately impressive storm structure in our neck of the woods from Tuesday evening into the first half of Wednesday. In addition; right about the same time Atlantic moisture should rev-up into the system in conveyer-belt like fashion later in the aforementioned period. Good vertical velocity and energy aloft should make for a good dump of precipitation later Tuesday into Wednesday morning...though as with most systems this season, heaviest precipitation will be south and east of us...a noted trend this winter. Snowfall rates in spite of temperatures initially falling just into lower to mid 30s after precipitation onset may approach an inch an hour in the late afternoon to evening time frame in heavy wet snow. This timing may change if the precipitation advance slows a bit. A mixed bag of precipitation is also still in the cards, especially over extreme Southeast Lower Michigan and mainly in the initial stages of the event.
(see explanation below). A stiff and gusty northeast wind at 15 to 25 mph with gusts to around 30 mph will accompany the precipitation  into early Wednesday.

                                                500H with vorticity est maxima's (X)

Now; the above scenario is all nice and good but she (500 MB Jet) also gets the boot from energy diving into her back/west side which why may help with troughing westward; will also help move things along to the east. Therefore; the center of the best action doesn't stick around quite as long as I would like to see for the BIG accumulations.

Besides less precipitation than earlier expected; another problem is the system still nicks Southeast Lower Michigan enough so that pockets or envelops of "milder, above freezing" ice-crystal melting air will also mess with our snowstorm (it always seems these things are never easy around here). This continues to bring the risk of mixed rain, snow and sleet mainly at the onset. While this churning of milder air is seen in pockets aloft and at the surface early in the event, this should ultimately be offset by dynamic cooling aloft especially when considering precipitation intensity - along with the drier, cooler air feeding the system from the northeast. However; being so marginal aloft in the temperature departure lets the door open for the risk of some mixed precipitation well into early Wednesday.

Need a refresher on what determines snow, sleet or freezing rain? Or not sure what each type is?
Check out a great tutorial @ http://www.nssl.noaa.gov/education/svrwx101/winter/types/

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

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Original Blog 2/23...

As mentioned in my last blog, our models were intimating another storm for this coming week and snow lovers should not give up hope. Latest forecasts of all the models continue those earlier projections of bringing a large storm and low pressure area toward the Great Lakes this upcoming Tuesday into Wednesday...with lingering affects possibly lasting into Friday.

Meteorological data for this storm is now (Sat AM 2/23) being sampled over the far Western states and thus; the model runs are starting to get a better idea of the atmosphere projected to develop this storm. All data thus far; promotes the development of a Texas Hooker type of low pressure system Sunday  into Monday that slides into the Boot-heel of Missouri by Tuesday morning. The center of the storm is then expected to slide northeast across the western Ohio Valley through Tuesday night and be over Southeast Lower Michigan by Wednesday morning. This system appears to have the capability of bringing both Gulf of Mexico and Atlantic moisture to Southeast Lower Michigan.

While preliminary data supports a more significant storm than this past Friday's weakening storm, questions still arise as to the nature of the precipitation. At this time; the best estimates from the early data points to a mixed rain and snow scenario to arrive Tuesday afternoon before changing to all snow sometime Tuesday evening lasting into Wednesday. Heavy amounts of snow are possible with this system especially if the majority of the precipitation received is, in fact snow. Since this time period is still 3 - 4 days out and as you know in this business; things can change - but look for updates on the progress of the system into Tuesday.

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

Update 2/25/13 - Risk of a Major Storm Increasing for Southeast Lower Michigan Along with Estimated Snowfalls Likely

Update 2/26/13...1150 AM
Mixed precipitation will advance across Southeast Lower Michigan during the afternoon quicker than initially anticipated...therefore a longer period of rain...snow...sleet and freezing rain will occur into at least early evening. Because of more mixed precipitation; snowfall amounts will be impacted, especially over extreme Southeast Lower Michigan. Further updates including snow amounts will be issued.

Update 2/25/13...

Snowfalls
Generally I look for a 4" - 7" total of heavy wet snow over much of region from this system through  Wednesday - with much of that snow falling late Tuesday into midday Wednesday. Eastern counties, especially downwind of Lake Huron may see highest with isolated 8" or so possible.  I will update if the system information changes going into the event.

Discussion
Overall very little has changed on our expected winter storm the past few days as most models continue to prog the storm in the track first outlined in the original blog 2/23. In fact; the major models are in remarkable agreement as to the general track of the low center with a subtle shift southward of both the 500H MB and surface low in the last 12-24 runs.

The European continues this lead (I originally chose in the initial blog below) with now both the GFS and the European pretty well in step. Of course; the devil is in the details...and in this case the problems lie in precipitation amounts and how much "warm air" gets entrained into the lower levels of the atmosphere. While this system somewhat resembles our Dec 26th storm it is much further north and thus; milder but at the same time the dynamics of the system are more impressive overhead as is its moisture feed from initially the Gulf and subsequently Atlantic.

The system has well developed features aloft including; a compact negative tilt structure that consolidates into a "bowling ball" shape that "hooks" for the Ohio pocket as she heads northeast. Meanwhile; the surface system along with the 700MB low follow along in good measure right into Southeast Lower Michigan and Northwest Ohio. And old rule of thumb with the 700 MB; to the left of center, generally the best snow can be expected in a mature system. And, while our storm is projected to weaken with time as she treks toward the Eastern Lakes; she still maintains a moderately impressive storm structure in our neck of the woods from Tuesday evening into the first half of Wednesday. In addition; right about the same time Atlantic moisture should rev-up into the system in conveyer-belt like fashion later in the aforementioned period. Good vertical velocity and energy aloft should make for a good dump of precipitation later Tuesday into Wednesday morning...though as with most systems this season, heaviest precipitation will be south and east of us...a noted trend this winter. Snowfall rates in spite of temperatures initially falling just into lower to mid 30s after precipitation onset may approach an inch an hour in the late afternoon to evening time frame in heavy wet snow. This timing may change if the precipitation advance slows a bit. A mixed bag of precipitation is also still in the cards, especially over extreme Southeast Lower Michigan and mainly in the initial stages of the event.
(see explanation below). A stiff and gusty northeast wind at 15 to 25 mph with gusts to around 30 mph will accompany the precipitation  into early Wednesday.

                                                500H with vorticity est maxima's (X)

Now; the above scenario is all nice and good but she (500 MB Jet) also gets the boot from energy diving into her back/west side which why may help with troughing westward; will also help move things along to the east. Therefore; the center of the best action doesn't stick around quite as long as I would like to see for the BIG accumulations.

Besides less precipitation than earlier expected; another problem is the system still nicks Southeast Lower Michigan enough so that pockets or envelops of "milder, above freezing" ice-crystal melting air will also mess with our snowstorm (it always seems these things are never easy around here). This continues to bring the risk of mixed rain, snow and sleet mainly at the onset. While this churning of milder air is seen in pockets aloft and at the surface early in the event, this should ultimately be offset by dynamic cooling aloft especially when considering precipitation intensity - along with the drier, cooler air feeding the system from the northeast. However; being so marginal aloft in the temperature departure lets the door open for the risk of some mixed precipitation well into early Wednesday.

Need a refresher on what determines snow, sleet or freezing rain? Or not sure what each type is?
Check out a great tutorial @ http://www.nssl.noaa.gov/education/svrwx101/winter/types/

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

_________________________________________________________________________________


Original Blog 2/23...

As mentioned in my last blog, our models were intimating another storm for this coming week and snow lovers should not give up hope. Latest forecasts of all the models continue those earlier projections of bringing a large storm and low pressure area toward the Great Lakes this upcoming Tuesday into Wednesday...with lingering affects possibly lasting into Friday.

Meteorological data for this storm is now (Sat AM 2/23) being sampled over the far Western states and thus; the model runs are starting to get a better idea of the atmosphere projected to develop this storm. All data thus far; promotes the development of a Texas Hooker type of low pressure system Sunday  into Monday that slides into the Boot-heel of Missouri by Tuesday morning. The center of the storm is then expected to slide northeast across the western Ohio Valley through Tuesday night and be over Southeast Lower Michigan by Wednesday morning. This system appears to have the capability of bringing both Gulf of Mexico and Atlantic moisture to Southeast Lower Michigan.

While preliminary data supports a more significant storm than this past Friday's weakening storm, questions still arise as to the nature of the precipitation. At this time; the best estimates from the early data points to a mixed rain and snow scenario to arrive Tuesday afternoon before changing to all snow sometime Tuesday evening lasting into Wednesday. Heavy amounts of snow are possible with this system especially if the majority of the precipitation received is, in fact snow. Since this time period is still 3 - 4 days out and as you know in this business; things can change - but look for updates on the progress of the system into Tuesday.

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

Stormy Weather; Update - 2/19/13...One Storm Down and the Other Out

Update 2/19/13...
Latest fragmented sampling of the short wave energy riding down the West Coast as I type, continues the recent modeling outcome of the system slated for late this week. The initial strong upper air dynamics along with strong surface development that moves into the Plains mid week; model consensus continues to weaken by forecasting the eventual demise of the storm as she rides into the Upper Midwest and Lakes region by Friday. While the system is still likely to bring some precipitation (mainly snow) to the region, it will be light and a far cry from foot or so several model runs projected in its early days out in la la land (as many meteorologists call it - or worse ;-). There still are storm potentials further out in the same "la la land" next week so snowstorm lovers don't give up just yet (but I wouldn't bet on it either as evidenced by this weeks). Recent upper air trends along with this being a favored time of year for the big storms, the season may be down but certainly not out!.

As mentioned in the initial post (and several times in others) these model projections of systems, especially several days out are always taken with a big grain of salt. What is interesting to me is that over the years (since the 1970s); the real change I've seen is how much better our models do in the shorter range; even 2 to 3 days out. Problems in the shorter range are more about exact timing, tweaking temperatures a bit or how much precipitation we do or don't get. The broad, overall trends of the hemisphere projected even several days out in the models, are now many times much better than years back. In my very early days with the NWS, there were more shorter term "surprises" especially where winter storms were concerned. As mentioned previously; the snowstorm of Dec 1st, 1974 was one of the more memorable storm misses I can recall. People went to bed Saturday night /30th/ (along with the early risers on the 1st) expecting to see 1 to 3" of snow on that Sunday, instead of the 19"+ that eventually fell.

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 aforementioned 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 the 20th, tomorrow during the 5 pm weather segment with other weather interview segments possible in the future. Any changes I will update. *Update 2/20; I was notified late this afternoon that the TV interview will be shown at a later date due to a scheduling conflict with Ms. Vogel. I will enter the new date here when confirmed with Hally.
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Update 2/16/13...
Model dynamics continue to advertise an active stormy pattern across the country next week. And, while coming into consensus about the first storm, now vary the path of the second. Basically; most models mature and fill the second storm quicker somewhere across the upper Mississippi Valley into the Great Lakes region this upcoming Friday (2/22/12).

Storm #1;
Down and out...

Even though a strong upper level jet (now over the northern Pacfic) is expected to dive into the Upper Midwest and subsequently fuel the projected deepening low slated for the Great Lakes; the center of the storm will pass well north of Southeast Lower Michigan (as projected initially) across the northern Great Lakes with little in the way of wave development further south along the front in the lower Great Lakes/Ohio Valley region (unlike previous runs). The energy with the storm remains focused more with the parent low in the tightening and deepening 500H MB trough. While some energy is still slated to ride over the lower Great Lakes at the base of the negtive tilting trough east of the Lakes that will  possibly enhance precipitation over eastern Lower Lakes, it will be more transitory in nature. In addition; initially the strong warm air advection advertized ahead of the system in the ridge axis will result in more warming of the atmosphere -more than early model runs suggested- enough so, to make this a mainly rain event in what precipitation advents north ahead of and along the front.

There is still should be enough cold air advection behind the front to change over any residual precipitation to snow early on Tuesday but since moisture will be leaving the area, I look for possibly just light accumulations in light snow or snow showers. Enough said.

Storm #2
Down but not out...

The second storm discussed in my previous post remains the more troublesome of the two as previous consistent modeling projections began to deviate the path and weaken the storm as she heads into the Midwest/Great Lakes Thursday into Friday. Latest consensus is to wrap of the upper dynamics of the storm faster and further west of the region. On that premise; the center of surface low moves west of the region, weakens and shears out as she elongates across the Upper Mississippi Valley eastward across the lower Great Lakes (see maps). The shearing/elongation of the system takes place as the upper/surface low encounters strong, somewhat blocking high pressure ridge to the northeast ...this acts as sort of a "squashing" and weakening effect on the storm. Subsequently; the storm not only weakens but its moisture is wrung out as it elongates. The best pools of moisture under this scenario would be west of Southeast Lower Michigan with the center of the upper/surface low and east- southeast of the region as the Gulf moisture is deflected toward the east (picture a fountain effect; water up and outward on both sides). Finally; all this action also would unquestionably slow the onset of the storm into Friday in our neck of the woods..

There still is conflicting guidance on the storm as she comes in on Friday; some models still deflect the whole storm center (and upper air support) south of the blocking, stacked strong high pressure and the storm undercuts the block toward the east across the southern Lakes/Ohio Valley region (see maps). Though weaker; this track is still similar to that of the original track proposed initially (and discussed on 2/13, below). If all this wasn't enough, with the storm occluding and maturing somewhere between the Upper Mississippi Vally and Lower Lakes, warmer air will also get a chance to be pulled into the system and thus, this opens the door for mixed precipitation to get into the mix, ;-).

In any event (and stated in the initial blog); this is still several days out and at this point, the sampling of the the Jet stream energy is very limited; mainly to satellite interpretation. Experience has taught me it is still too early to go with one model's results and to discount accumulating snow from this storm over Southeast Lower Michigan. At this time, even with the worst case scenario proposed for snowfall in our region, would still bring at least some accumulating snow to Southeast Michigan on Friday. Yes, she's down but not out, so stay tuned.

BTW..it's not over as some models are intimating a third storm developing back to the southwest at the base of the Southwest 50H trough for early the following week.

Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian
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Original blog discussion; 2/13/13...
For several days now; many of our extended models have been intimating a change in the upper wind pattern across the country next week. This pattern per se' is really nothing new as it reflects basically our recent pattern, it's just more active and faster with potential storms results of better phasing and/or energy available for winter storms. This IS the classic time of winter season when the big ones are more likely to develop...mid February to mid March. Reasons are plentiful; strong winter jet phasing with an intensifying (due to spring in the offing) sub-troipcial jet; better moisture supply from the warmer waters of the Gulf of Mexico as southerly winds feed these storms and; low level Arctic air mixing with warmer air from the south, for a better contrasting mix fueling the storm.

Check out the biggest snow storms of Detroit and when they occurred;

Eight of the biggest top ten snow storms occurred in February or later in Detroit>>>

Detroit's Heaviest Snow Storms
Rank	Date	Amount
1	April 6, 1886	24.5
2	December 1-2, 1974	19.3
3	March 4-5, 1900	16.1
4	February 28-March 1, 1900	14.0
5	December 18-19,1929	13.8
6	February 12-13 1894	12.8
7	February 19, 1908	12.6
8	January 31-February 1,1881	12.5
9	February 9,1911	12.3
10	March 3-4,1895	12.3

Therefore; look for a stormier pattern to evolve next week and possibly right through the end of February. This all hinges on the projected evolution of the jet stream at 500 MB /18,000FT/, moisture available to the low pressure/storm development and track of subsequent storms. This is just a heads-up at this time as any development projected this far out (about a week or better) must be taken as just as a possibility and never a certainty!

Early indications are two storms may affect Southeast Michigan next week; one storm Monday night into Tuesday / 18-19th /. This storm could start out as a mixed bag of precipitation later Monday which then changes over to snow. At this time; this first storm appears to be the weakest of the two but still may drop accumulating snow on the region by Tuesday.

The second storm looks to be the strongest of the two and is projected to approach Southern  Michigan from the Southern Plains Thursday evening and be over the region by Friday morning / 21-22nd /.

Models projections for this storm is to wrap-up somewhere from central Great Lakes into the northern Ohio Valley at this time. The GFS model puts the storm center right over Southeast Lower Michigan Friday morning with heavy snow with some places in excess of a foot....again remember; this is in la la land! Latest Euro tracks the storm further west over Southwest Lower Michigan; so stay tuned to the projected track as the time approaches. The development on this storm also has been fairly consistent for several days now and along with the snow; a mix bag of precipitation would also be possible were the storm to track over or to the west of the region.

Again; there is a lot of time between now and next Tuesday and Fri and changes can and will occur. The main reason of this very early posting is because of the consistently of the models storm development and possible impacts.The important tracks of these systems remain "up in the air" (pun intended). Look for updates to be available as the time approaches.

And now; do you have some young school age snips around the house that love weather?

Check out this great site for school age children on winter storms and lingo!

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