2/23/16

2/24/16 - Update - Winter Storm Affecting the Lower Great Lakes Heavy Snow and Rain; Critical Temperatures Creating Dividing Line For Snow Accumulations

2/25/16
Storm Smmary and Snowfall totals:

http://www.weather.gov/dtx/February24-25SnowfallSummay


Update 2/24/16 Noon
Little change in overall forecast area delineations for snow but with a few inch adjustments in overall final snowfalls as storm appears to be tracking a bit further east. Latest noon surface observations/trough position due to pressure falls indicate a track more toward central (rather than west central Ohio) and then subsequently northeast Ohio.


Updated Forecast Through Thursday

Snowfalls of 2 - 4" are likely across the mildest areas of Southeast Michigan over the Southeast corner Lower Michigan with mixed rain and snow including the east and Southeast portions of Metro Detroit; most of which will fall overnight Wednesday into Thursday. The least amounts of snow being near the Ohio border. 

Areas away from the Southeast corner;  including much of the western suburban Metro Detroit areas, west into Ann Arbor and north into Pontiac and Port Huron are likely to see 4" - 8" of the snow (generally highest amounts over western and northwest areas).  Snowfalls further west, northwest and north toward South - Central Michigan and up into Flint, Saginaw and Michigan's Thumb can expect general snowfalls of 7"- 11" (local areas of higher snow amounts are possible especially downwind of Lake Huron) with all precipitation, snow. 

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Previous blog 2/23/16

Latest morning guidance continues to advance major storm toward Lower Great Lakes and Southeast Lower Michigan. The biggest problem of forecasting precipitation type continues to be where the rain/snow line will set up across Southeast Lower Michigan during the heaviest precipitation from the storm. All areas will still see snow on the backside of the system later Wednesday night and Thursday. The dilemma comes in during the first half of the period when the heaviest precipitation should moves into the region during the day Wednesday into Wednesday evening. This itself (daytime arrival in late February) suggests the more likelihood of rain or rain mixed with snow over extreme Southeast Lower Michigan as precipitation advances into the region during the daylight, when the air mass will be naturally be a bit warmer. Another problem that comes is how close the low pressure gets to Southeast Lower Michigan. The closer it gets, the more likely slightly warmer air is pushed northward into the region. Models continue to vary somewhat on the air column /profile/ above the ground over Southeast Lower Michigan and its temperature distribution.

However; a nudge to the northwest has been noted in general which will affect snowfall amounts over the region during Wednesday and Wednesday evening. Note the model maps..


GFS

 Top map above is Wednesday early afternoon, the second is Wednesday evening.

NAM



The above map is Wednesday Evening

EURO


The above map, the European also has the R/S line (light blue) advancing slowly northward into Southeast Lower Michigan as the low tracks northeast across northern Ohio (see track above).

Add to this; it must be remembered that the column of air will be cooling aloft later toward the evening as colder air in the higher levels of the atmosphere advances across the same region;while the ground temperatures are steady to slowly falling

All this in mind; I'm pushing the better snow amounts away to the northwest from the Southeast corner and Detroit Metro area.

Previous Forecast

At this early juncture; snowfalls of 3 - 5" are likely across the mildest areas of Southeast Michigan over the Southeast corner Lower Michigan. Areas away from the Southeast corner; which includes much of the Metro Detroit Area west into Ann Arbor, Brighton, Howell, Flint and areas west and north where general snowfalls of 5"- 9" (highest amounts will be further away from the Southeast Lower Michigan corner where isolated higher snow amounts are possible). Besides of snow of course, will be the very strong northeast winds of 20 - 30 mph with gusts near 40 will cause problems with power and tree limbs along with the heavy snow.

 

Updated Forecast

Snowfalls of 1 - 3" are likely across the mildest areas of Southeast Michigan over the Southeast corner Lower Michigan including the east and Southeast portions of Metro Detroit; most of which will fall overnight Wednesday into Thursday. The least amounts of snow being near the Ohio border. Areas away from the Southeast corner;  including much of the western suburban Metro Detroit areas, west into Ann Arbor and north into Pontiac and Port Huron are likely to see 3" - 7" with most of the snow falling later Wednesday afternoon into Thursday.  Snowfalls further west, northwest and north toward South - Central Michigan and up into Flint, Saginaw and Michigan's Thumb region remains unchanged where general snowfalls of 6"- 9" (where areas of higher snow amounts are possible) with most if not all precipitation, snow. 

 

Besides of rain and snow of course, will be the very strong northeast winds of 20 - 30 mph with gusts near 35 will cause problems with power and tree limbs along with the heavy snow in areas indicated.

Keep in mind that all guidance and logic points to a rather sharp line of accumulation snow to rainy wet areas.  This continues to be a changing situation and therefore updates will be sent; whether or not the snowfall amounts change

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 Previous blog

As mentioned yesterday, tomorrow we'll update the current expected major storm with the latest 12z guidance (Feb 23rd, 2016 -7AM EST) and adjust expected storm affects on the region by mid afternoon.

Below; we'll compare our present day storm with the storm that started it all for me as far as a fascination with snowstorms and thus, increased my desire to study weather. It ironically, occurred on the same date as our expected storm this week - The anniversary of Snowstorm of February 24-25th 1965! Just passing it's 50th anniversary last year, I remember the day well.

The best part, besides obviously the snowstorm ,was being off two days from school. In fact; those two days, February 25-26th 1965 were the only two days back in the old days (well before kids started to get off of school for anything weather related) that I ever was let off of school in grade or high school. I went to a Catholic grade school in northwest Detroit /St. Monica/ and high school /Bishop Borgess/ therefore; getting let out of school because of a snowstorm was rarely heard of anyway.

Anyway; on the morning of the 25th, which my memory recollected was a Thursday (and checking back on my computer verifies this) we were awaken to a heavy snow cover along with drifts I had never seen in the Detroit metro area growing up my 10 years previously. Snowfalls varied across the metro Detroit area but most were with a few inches of a foot. Officially in the far northwest part of Detroit, I measured a foot in several places around the house. Besides the heavy snow cover were the moderately strong, gusty winds which built drifts in the city lots/yards to up to 2 1/2-3 feet in places from my memory.

Let's take a look at new items from that memorable day for many...


SNOWSTORM Feb 24-25TH 1965

There are close similarities in the expected modeled storm this week, 51 years later and the actual Snowstorm of February 24-25, 1965.  Besides the obvious dates; ironically the Storm of '65 in its infancy was also a Gulf Low that developed in the same region as the models are predicting this weeks storm development on Wednesday, the 24th. The  storm development is expected down over the Louisiana/Gulf Region. The upper air appears very similar as does the surface low development and movement. One major difference with this week's weather is the milder temperatures expected ahead of/and during the storm which could obviously cut down on snowfall amounts. This especially will be noted where rain or rain mixed with snow falls

From the Toledo Blade, which gives a fairly thorough synopsis of the Feb 24-25th, 1965 storm...

"This could be called the "Midwest/Ohio Valley Snowstorm of 1965" 7.8" at Toledo, 11" at Detroit, 12.9" at Flint, 9" at Jackson MI, 10.3 " at Lansing, 17.9" at Saginaw, 7.5" at Grand Rapids, 12.7" at South Bend, 7.5" at Fort Wayne, 12.5" at Indianapolis, 10" at Chicago, 7.6" at Peru IN, 9.8" at Lafayette, 8.4" at Evansville, 6" Bowling Green KY, 3" Cincinnati, 7" Paducah."

"The surface low tracked from Louisiana to Cincinnati to north of Pittsburgh to north of Montreal. The rain-snow line was near a Toledo to Indianapolis line. It was a strongly deepening low from around 1002mb to 983mb in 24 hours, to 976mb in 30 hours.

It was 12 degrees and windy at Toledo after the storm ended. It is interesting to note this situation was along with a strong Greenland block but the upper level flow off the East Coast did not allow a coastal low to develop. This was a definite problem for transportation in Toledo, according to the Toledo Blade. It was also the largest single-storm total snowstorm at Toledo in the previous 14 years, according to the Toledo Blade."

500 MB Heights 



Surface


Detroit after the '65 Storm

 

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



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Previous blog 2/22/16

Major Late Winter Storm Likely to Impact Southeast Lower Michigan With Strong Winds and Heavy Snow!

After several days on various tracks of the possible impending storm, better sampling of the atmosphere is indicating very strong dynamic system with copious moisture will affect the region. A more definitive track is beginning to emerge even though this system is still a good few days away, it appears all models have a better handle on the outcome now.

Still; the exact track of the storm/low will have a major impact of snowfalls across Southeast Lower Michigan and Lower Michigan, as a whole. Along with the crucial track of the low determining snowfalls will be the existing relatively mild temperatures ahead and during the early stages of the storm on Wednesday when rain, mixed rain and snow is expected. All precipitation is expected to change over to all snow by Wednesday night into Thursday morning.

At this early juncture; snowfalls of 3 - 5" are likely across the mildest areas of Southeast Michigan over the Southeast corner Lower Michigan. Areas away from the Southeast corner; which includes much of the Metro Detroit Area west into Ann Arbor, Brighton, Howell, Flint and areas west and north where general snowfalls of 5"- 9" (highest amounts will be further away from the Southeast Lower Michigan corner where isolated higher snow amounts are possible). Besides of snow of course, will be the very strong northeast winds of 20 - 30 mph with gusts near 40 will cause problems with power and tree limbs along with the heavy snow.

This storm has more of a Gulf Low characteristic which generally contain the best moisture access along with a very strong southern jet streak in the upper atmosphere; classic of the deeper, more intense low pressure. It has been awhile since a true Gulf Low has affected the Lower Great Lakes and in fact, much of the country as most storms on the East Coast this winter have been Coastal Storm development with impulses originating from the West or Northwest. We saw numerous cousins of the Gulf Low over the Texas/Oklahoma/Arkansas region during the severe winter of 2013-14 and late last winter.



All indication are the storm will take shape over Southeast Texas/Louisianan/Gulf of Mexico as an intense subtropical jet streak containing impressive winds of 120-130 knots at the higher levels of the atmosphere /250-300 MB, or 33Kft-35Kft/ and strong horizontal and vertical velocities. It's certainly without question; the most impressive low pressure/storm center projected to affect the region in this benign winter season, anyway!

Next will take a look at specific upper winds and storm tracks of the 12Z/022316 models along with and a little Weather Historian history.  Look for updates during the next few days on this impending storm!

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