Winter 2018-19: A Disappointment for Snow Buffs But Not Necessarily for Cool Weather Lovers

The onset of winter weather was a struggle in the Winter of 2018-19 across much of extreme Southeast Lower Michigan for cold temperatures, snowfall and storms as a whole.  Many of the impressive snow produces rode across Northern Michigan or occasionally further south in the Ohio Valley with much of Southeast Lower Michigan missing out. Strangely enough; the month of November contained some of the more frequent snowfalls and totals for the season.

December’s weather was exceedingly mild and non-eventful as far as snowfall. Temperatures averaged several degrees above normal – more classic of a stronger El Nino winter rather than the weak Madoki El Nino Winter at hand. Complimenting the unusually mild weather was the lack of snow with generally less than an inch falling across the entire region; far below the normal of 7-10”.  

January entered the scene as December left with overall; relatively mild winter weather holding sway for the first two-thirds of the month. A sharp change in the jet stream later in the month brought true Arctic cold in two aggressive blasts. One cold swoop followed the first winter snowstorm the 19-20^th creating generally 4-7” of snow over the south and 1-4” over the north with temperatures plunging below zero the 20^th - 21^st. After a brief reprieve from the cold, another more serious cold wave surged south from the Arctic near the close of the month on the 28th and persisted right into the opening of February. Temperatures cratered down into the 10 to 20 below zero range on the 30^th and 31^st and zero to -10 on February 1^st. 

February turned out to be an average month as far as temperatures across all of Southeast Lower Michigan. Snow varied from below average over extreme Southeast Lower Michigan including Detroit and Ann Arbor southward, to above over central and northern areas including  Flint, Saginaw Bay and the Thumb Region.

For the “winter-proper” /Dec-Feb/ period; temperatures averaged-out within the normal range over all of Southeast Lower Michigan. As stated; winter in reality did not really get going until well into January with the cold air arriving with a vengeance later in the month. Snowfall was on and off through the season with December and March the lighter of the snowfall months, February was mixed and November and January; the snowiest relative to normals.

While the winter temperatures averaged normal; the overall cold season /Nov - Mar/ averaged colder than normal and is the main reason the "winter" season felt so long. Here the biggest offender was November with temperature departures 4 1/2 to 5 1/2 below the normal. That; combined with a rather snowy month for November brought in the winter deceivingly early. This was especially noticed since the balance autumn up to then, contained long lasting warmth and a rather late tree-leaf falling and baring. This was notably problematic for homeowners, gardeners and landscapers with snowfalls on leaf piles to be cleared.

The temperature statistics below show the winter months, the winter temperature average and departures. This is for Detroit, Flint and Saginaw with SE Michigan data averaging all three stations together.  In addition; I've included the cold season temperatures/departures spoken about above. Note the entire cold season Nov-Mar averaged a degree below normal for the five month period. Especially significant when you consider December averaged a good four degrees above normal for contrast ( Dec stats also included in the cold season).

WINTER OUTLOOK/ANALOGUE PERFORMANCE

FORECAST

Temperatures - Normal to Below

As with the majority of winters; look for temperatures during the 2018-2019 winter to be quite changeable as opposing air masses via for dominance under a fluctuating jet stream. The ongoing pattern recently experienced this fall is also telegraphed in the Winter Analogues for 2018-19. 

Various computer guidance for the upcoming winter is also having difficulty with what type of El Nino will occur (see model section). While analogues and some models suggest an a typical El Nino pattern, my research also confirms this with colder temperatures than what is typical. I believe during this winter; the Pacific jet will be fighting against a sometimes more impressive colder northern Polar/Arctic Jet coming in from Canada. This winter's analogues are strongly suggesting a normal to below normal temperature winter is at hand with the clear majority pointing in that direction (see Analogues, below).

In the final analysis; I look for Southeast Lower Michigan winter temperatures to average +1.0F  to  -3.5F of normal.

Epilogue: Resultant Winter Temperature Departure /+0.7/  Resultant Cold Season Departure /-1.0/

Results confirmed a normal winter temperature along with  a /+0.7/ numerical figure for all of Southeast Lower Michigan - as the forecast reads. Normal range used +1.0 > -1.0; while below is <1.0 degree. As far as the cold season average; that came in one degree below average (see chart). The two upper air winter patterns expected; materialized. In the analogue monthly discussion; December had the most likely chance to average above normal, as was the case.

The overall pattern was reflected well in the analogue projections for the winter. As a result; the more dominant Pacific jet and especially timing (also see cold season "Epilogue") was also reflected in the pattern.

FORECAST

Precipitation (Rain & Snow water equivalent) - Normal to Below

While jet stream pattern has been busy as of late; as the El Nino sub-tropical jet rev's up into the winter, this is likely to drag the southern, wetter storm track south of the Lakes into the Ohio valley and points south and east - up the Coast. Most analogues and models suggest a drier than average winter. Keep in mind however; many times we have a below normal precipitation amount with normal or even above normal snowfalls. 
 

Epilogue: Resultant 2018-19 Seasonal Snowfall – Normal to Below

Season snowfalls behaved well to forecast of normal to below. The below normal snows fell across the extreme southeast corner of lower Michigan; normal across the remainder of the area using the analogue scale posted. The storm tracks discussed did materialize well north of Southeast Michigan and in the Ohio Valley. While the snowfall season started with a snowy November, snowfall frequency dropped off somewhat in the majority of the snow season.

Heavy winter precipitation fell to the northwest of Southeast Lower Michigan and to the south. The heaviest amounts were concentrated in the Upper Midwest and northern Great Lakes and across the middle Ohio Valley (see precipitation/snow maps below). The wetter above normal precipitation is clearly seen in these areas while the drier, normal to below normal area is reflected across Southeast and South-central Lower Michigan. According to the precipitation maps, the driest or below normal area occurred from the Jackson area east into southern Metro Detroit and points south; or basically south of I-94 (this also reflected snowfall).

From the Analogue Outlook: Actually; all (analogue) months had quite a number of below normal snows with somewhat less above normal - which lead to the slightly below normal winter snows as a whole.  As always, the main thing we are concerned with are the snowfall trends of the winters and to a lesser extent; the snowfall totals. The main trend was for normal but on the lighter side of normal and thus far; we are following the dominant trend seen early with a cold and snowy November.

Earlier analogue year winters - which were the balance of the sample analogues this go around - strongly suggested a normal to below snowfall winter. This clearly did happen in both the snowfalls and precipitation across Southeast Lower Michigan (again; see precipitation and snowfall percent of mean maps below).

(Note - Below Normal snowfall; less than /- 5.0"/ of the winter average snowfall.  Normal snowfall; +/- 5.0" of the winter average snowfall and above Normal snowfall; better than /+5.0"/ of snow above the average).

SNOWFALL SEASON AMOUNTS/DEPARTURES

SEA TOT
31.3	DETROIT
42.5
-11.2	Depart
52.4	FLINT
47.4
5.0	Depart
44.0	SAGINAW
41.5
2.5	Depart
Snow	Inches
Below	<5.0
Normal	>-5<5.0
Above	>5.0

Temp Maps

Precipitation and Snow Maps

SNOWFALL MAP ACROSS SOUTHEAST LOWER MICHIGAN SNOW SEASON 2018-19

Well; Summer's just around the corner and will the cool weather persist into the summer? Look for a short discussion on the Spring of '19 and the Summer 2019 Outlook late May-early June time-frame.

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