Preliminary Winter of 2003-04 Review and a Peek into Spring 2004

Written by: William R. Deedler, Weather Historian
National Weather Service Detroit/Pontiac, MI
March 8th, 2004

Quick jumps on this page:

Note: Dark red and italicized text is taken directly from the 2002-03 Winter Outlook issued in October, 2002.

Several traits of the selected past winters highlighted in the Winter 2003-04 Outlook issued Nov 15th, 2003 were reflected well in the patterns observed this winter in both temperature and precipitation. Officially, the winter (Dec-Feb) average temperatures are in across Southeast Lower Michigan. Before we check those out, let's look back at the Winter 2003-04 Outlook issued last fall and what the past selected winters suggested:

Temperatures:

Our earlier autumn outlook called for considerable temperature swings (a.k.a. roller-coaster pattern) to materialize this fall. It is felt that the roller-coaster pattern will carry over into the winter, though not being quite so frequent. This is quite a change from last winter, where weeks of what seemed like never-ending cold prevailed. Therefore, the temperature pattern of the Winter of 2003-04 is expected to be more variable with ups and downs. Periods of cold will be offset by occasional periods of above (or even well above) normal temperatures. That being said, overall temperatures should still average near normal to below. The in-house study suggests the coldest weather of the winter will likely go along with climatology with January and February having the best chances (there were only a few cold Decembers in the data).

The roller-coaster temperature pattern that commenced in the fall and predicted to persist through this past winter did indeed continue and was reflected in the winter data on a monthly, weekly and sometimes even daily basis. Examining the monthly temperatures and snowfall thus far (through February) for the winter at Detroit, Flint and Saginaw revels some interesting statistics:

2003-04 Winter Average Temperature (T) and Snowfall (S) so far (Chart-1)
 
Detroit Flint Saginaw White Lake

Dec (T) 33.1/+3.4 32.1/+5.4 30.3/+3.3 30.3/+
(S) 3.7/-7.4 10.3/-1.3 12.4/+2.2 16.6/+
 
Jan (T) 20.1/-4.5 17.2/ -4.1 15.1/ -6.3 15.7/--
(S) 14.0/+2.1 24.2/+11.0 24.4/+12.6 28.9/++
 
Feb (T) 28.5/+1.3 24.9/+1.1 21.9/-1.9 24.8/-
(S) 0.9/-8.4 6.1/-3.3 10.5/+2.2 7.6/-

Average
(T) 27.2/+0.1 24.7/+0.8 22.8/-1.6 23.6/-
 
Snowfall thru 2/29/04
(S) 19.0/- 43.1/+ 47.6/+ 53.1/+

1971-2000 30 Year Normals
(T) 27.0 23.9 24.0
(S) 44.0 48.3 44.5
100 Year Average
(T) 26.5 M M
- Below Normal       -- Well Below Normal       N Near Normal
+ Above Normal       ++ Well Above Normal       M Missing
The + or - at White Lake (DTX) is an estimate of below or above normal since norms have yet to be established

Note the wide monthly temperature swings that played out during the recent winter in the chart above. These wide temperature swings were strongly suggested by the temperature variability reported in the in-house study in the Winter Outlook. It was precisely because of these notable temperature swings that a two category outlook of normal to below normal temperatures was used for the entire winter. Wider swings in temperatures make it more difficult to pin down the final outcome of the dominating trend. In any event, this worked out fine since temperatures over all of Southeast Lower did average around normal to below.

The winter started out particularly mild with all stations recording well above normal temperatures for the month of December. In fact, with the average temperature of 32.1 or 5.4 degrees above normal at Flint, December 2003 became the eighth warmest December on record. The mild December also matched with the in-house study where there were more normal to above normal Decembers with only a couple of cold Decembers.

While January and/or February had the best chance to be cold, there were only a couple of winters where both months turned out cold and therefore, contained well below normal temperatures. January 2004 was no exception as it contained the coldest weather of the winter along with numerous snow events. Temperatures across the region averaged some four to six degrees below normal and since January is normally our coldest month, that made it only worse! In fact, this past January turned out to be even colder than our cold January of 2003 at all three stations (note below).

                           T e m p e r a t u r e s
                  Detroit              Flint             Saginaw
Jan 2003          20.5                 19.2              18.3  
Jan 2004          20.0                 17.2              15.1

February continued the cold trend of January well into mid month. After mid month, however, temperatures began to moderate nicely. So much so that by the last week, the relatively "balmy" temperatures finally melted several weeks of accumulated snow. And speaking of snowfall, how has the Winter 2003-04 Outlook handled that part of the prediction so far?

Snowfall:

As evidenced by the 13 winters in the study, snowfall amounts were quite variable (more so than any preceding study), with snowfall ranges from as little as near eight inches (Saginaw's 7.8" during the Winter of 1941-42) to a whopping 87" /87.2/ at Saginaw in the Winter of 1966-67. This, in itself, displays no persistent discernable pattern for snowfall. However, there were other more subtle trends noted while looking back over the available years and recent patterns. While the average for snowfall in the research came out near normal, the number of "snowy" winters did outnumbered the "snowless" winters. It was noted that when the winters contained below normal snow, they also tended to be the driest overall. The study hints that (and this too, would be unlike last winter) the heaviest snow may fall from Detroit's northern suburbs, northward up into the Flint and possibly the Saginaw area, rather than from Detroit south to the Ohio border. Overall, most areas should see close to normal snowfall with locally above normal.

As one can see by the Winter 2003-04 chart, the snowfall pattern so far this season does paint the heaviest snowfall across Detroit's northern suburbs, northward into Flint and the Saginaw Valley. While above normal snow did fall across the areas mentioned, below normal snow so far has been recorded over the extreme Southeast Corner of Lower Michigan. This area basically extends from Southern Wayne and Washtenaw Counties, south to the Ohio Border. Ironically, this is the exact opposite of last winter (2002-03) where the heaviest snow fell over extreme Southeast Lower Michigan (Detroit Metro Airport recorded 60.9" last year versus just 19.0" so far this winter).

Comparing the month by month snowfall (see Chart-1) with the in-house study revels the following:

Along with the mild temperatures at beginning of the winter, snowfalls were generally lighter than normal. Where there was above normal snowfall in December, it fell in the projected snowy areas but still, it was only a few inches above the normal. Specifically at Detroit, the study indicated the chances of below normal snow in December were high with 9 out of the 13 (or nearly 70%) supporting below normal snow. This matched well with the outcome since only 3.7" of the 11.1" normal fell.

Along with a big dip in the temperature pattern in January, came a big rise in the number snowfalls. The month of January was exceedingly busy with low pressure systems tracking through the Great Lakes Region. Alberta Clippers, Colorado and Texas Panhandle Lows were in abundance and brought the several snowfalls to our region.. Needless to say, with all the storm activity over the region, snowfall totals for the month ranged from above to well above normal. The highest snowfall departures again, fell in our projected snowy areas. Both Flint and Saginaw recorded their sixth snowiest January on record (and Saginaw's records go back over a century /1900/). Not only was this past January one of the snowiest on record at these and other nearby locations but January was also the eighth snowiest month on record at Flint and 12th snowiest month at Saginaw!

Comparing the in-house study winters to the winter of 2003-04 so far:

A quick glance at the variety of winters in the original in-house study does intimate which of the winters this past winter, so far, has resembled (and again, this is mainly as far as the overall trend...not necessarily actual amounts).


Winter Average Temperature Snowfall (Year)
  Detroit Flint Saginaw Detroit Flint Saginaw

1971-2000
30 Year
Normals-
27.1 23.9 24.0 44.0 48.3 44.5
100 Year
Average-
26.5 - - - - -

Winter:
1900-01 23.6 21.0* 22.5 41.7 - 54.3
1919-20 20.9 (9) 16.3* 16.7 (4) 43.5 - 41.2
1932-33 30.5 -16- 30.2* 28.7 -8- 25.9 18.5 24.5 -12-
1941-42 28.0 25.7 25.1 23.4 -17- 26.9 -6- 7.8 -1-
1952-53 32.3 -8- 28.6 -4- 28.3 -10- 16.6 -7- 23.4 -4- 20.0 -3-
1958-59 23.1 (18) 17.9 (3) 18.3 (7) 37.2 61.5 (8) 44.3
1966-67 27.3 23.4 23.7 50.6 78.6 (2) 87.2 (1)
1974-75 28.1 28.1 -7- 27.8 -12- 63.1 (7) 82.9 (1) 45.4
1977-78 20.4 (7) 19.1 (5) 17.9 (6) 61.7 (8) 50.6 (20) 55.6 (20)
1978-79 21.3 (10) 18.4 (4) 17.4 (5) 35.6 52.0 (19) 55.9 (19)
1980-81 24.6 23.6 21.9 38.4 36.4 -20- 41.4
1992-93 28.9 26.1 25.0 52.2 53.2 (16) 47.7
2000-01 25.0 22.9 (18) 22.5 39.0 53.4 (14) 67.8 ( 7)

Averages: 25.7 25.4 22.8 40.7 48.9 ** 45.5


(  ) Coldest or Snowiest Ranking
-  - Warmest or Snowless Ranking
*Not an Official Record and not in ranking (Official Records Began in 1942)
**Sample Incomplete and Therefore Not a reliable Snow Average

SPRING OUTLOOK:

The spring data, like the winter data, shows quite a variety of potential dominant weather patterns. This was expected since this is typical of the overall Neutral to weak El Nino pattern. This is why fine tuning with these local studies may help point us in the right direction. Also, please note while discussing weather trends of particular months, the overall trend discussed may actually show up intra-month rather than exactly between the month's open and close. Again, it is the trends of the spring we are mainly concerned with and we'll try our best to get a handle on.

Very early in the spring, anywhere from mid February into March, the data showed a significant preference for above normal temperatures, especially if more weight is given to 1979 (our closest anomaly so far), 1981 and 2001. Unfortunately, this did not necessarily indicate an early spring (as you will see as you read further) Generally this streak of nice weather lasted 2-4 weeks. The entire month of March showed very mixed data with six out 13 having below normal temperatures, two having near normal temperatures, and five out of the13 above normal temperatures. There was also a break in the storm action during the same 2-4 week period (sometime from the second half of February into March). This also has shown up this year as mid February into early March has indeed been mild with little snowstorm activity.

What about the rest of Spring 2004?

One thing true to most springs (and very predominant in our previous few outlooks) are the fluctuations in the temperature patterns. The continuation of the "roller-coaster" pattern in the spring holds true, especially during these Neutral to weak El Nino Springs. While a mild period was indicated very early in the spring, temperatures mid March into April tended to revert back to the normal to below normal regime. In addition, while there was a drop in snowfalls during that very early spring mild period, there was a notable increase again in April. In fact, seven out of the 13 Aprils showed near normal to above normal snowfalls, while six showed below normal. This, compared to nine out of 13 Marchs having below normal snow. Remember though, it is the trend for the spring we are concerned about and not necessarily the exact monthly timing. Therefore, this data does intimate the possibility of some notable late season (mid March into mid April) snows.

Later spring (May) indicates near normal to below temperatures with normal to above normal rainfall. The good news here was that none of the Mays had snowfall, though there were more Mays with below normal temperatures than above (seven below, versus three above and four near normal).

Storm Activity

Several of the most anomalous years showed peak in thunderstorms early and again later in the severe weather season. Both April and June show relatively busy periods with several days of thunderstorms. It was interesting to note that there was a quieter period of lesser storm activity coming mainly in May. The current track of the low pressures and fronts, along with the continuation of the overall amplified and progressive upper air pattern, suggests a busy early severe weather season. The entire severe weather season, however, does not necessary look to be as busy as the entire season was last year. We shall see.

Look for a brief write-up about the spring when the Summer 2004 Outlook is issued in June.


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