WeatherHistorian-SeMI: 02/01/2013

2/26/13

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

2/23/13

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)

2/13/13

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