Well Punxsutawney Phil brought two messages this Ground Hog Day. First;
there will be six more weeks of winter (he must be looking at my
Outlook). Second; with the ups and downs in the temperature
department this winter, he doesn’t know whether to come out for the
spring or scurry back into his warm hut before freezing to death and
thus:
Certainly
the most notable trend seen (and felt) this Winter of 2017-18 thus far,
have been some impressive, but thankfully intermittent Arctic cold
outbreaks. The worst of the cold arrived in time for Christmas;
accompanied by a snowstorm with the cold persisting right into the the
first week of the New Year.
This
winter's snowfall across Southeast Lower Michigan hasn't been absent
but the associated pattern of storms that produced much of it have been
rather mediocre and infrequent, especially in January. There have been almost predominantly clipper-type systems this winter
with the moisture rich Gulf helping to create Texas/Arkansas Lows being mainly absent.
Over Southeast Lower Michigan; areas around and south of I-69 to the Ohio border have received normal to above normal snowfall with the heaviest core extending from the I-69 corridor including Flint, south into the far north and northwest suburbs of Detroit. Strangely enough, areas just a bit further north across the Saginaw Valley have only seen about half the norm. Earlier projections of above normal snows for the Saginaw Valley doesn't look likely unless that region receives a some good snowfalls into spring.
Best snows fell in December thus far with two notable storms - the 13th and Christmas Eve into Christmas Day. While creating a picturesque Christmas, the resultant snow also created horrible driving conditions for holiday travelers. Finally; even with some rain storms during January thaws, overall precipitation remains clearly below normal across the entire land.
Over Southeast Lower Michigan; areas around and south of I-69 to the Ohio border have received normal to above normal snowfall with the heaviest core extending from the I-69 corridor including Flint, south into the far north and northwest suburbs of Detroit. Strangely enough, areas just a bit further north across the Saginaw Valley have only seen about half the norm. Earlier projections of above normal snows for the Saginaw Valley doesn't look likely unless that region receives a some good snowfalls into spring.
Best snows fell in December thus far with two notable storms - the 13th and Christmas Eve into Christmas Day. While creating a picturesque Christmas, the resultant snow also created horrible driving conditions for holiday travelers. Finally; even with some rain storms during January thaws, overall precipitation remains clearly below normal across the entire land.
On the whole, temperature have averaged below normal but that certainly
doesn't even begin to reflect the roller-coaster ride they've been on to
get there. Want proof ? Just take a drive on many of the local paved roads -
the assortment of old and newly eroded crop of potholes will attest to it.
This has been an extraordinary pot-hole creating winter with its
frequent deep freezes and notable thaws. Just looking at the
Local Climatic Data /F6/ from Detroit thus far,
displays the up/down roller-coaster pattern well. Days with above normal temperature
departures are depicted/shaded in red, while below are in blue. Obviously, up/down departures happen daily but the persistence and magnitude (especially below normal) is what catches ones eye.
PRELIMINARY LOCAL CLIMATOLOGICAL DATA (WS FORM: F-6)
STATION: DETROIT MI
MONTH: DECEMBER
YEAR: 2017
LATITUDE: 42 13 N
LONGITUDE: 83 20 W
TEMPERATURE IN F: :PCPN: SNOW: WIND :SUNSHINE: SKY :PK WND
================================================================================
1 2 3 4 5 6A 6B 7 8 9 10 11 12 13 14 15 16 17 18
12Z AVG MX 2MIN
DY MAX MIN AVG DEP HDD CDD WTR SNW DPTH SPD SPD DIR MIN PSBL S-S WX SPD DR
================================================================================
1 49 31 40 5 25 0 0.00 0.0 0 3.3 12 250 M M 5 13 250
2 50 31 41 6 24 0 0.00 0.0 0 4.2 14 200 M M 9 1 16 190
3 55 30 43 9 22 0 0.00 0.0 0 4.5 9 170 M M 4 18 13 250
4 56 36 46 12 19 0 0.02 0.0 0 12.5 26 190 M M 10 33 180
5 58 30 44 10 21 0 0.02 T 0 23.4 32 240 M M 9 45 210
6 41 27 34 1 31 0 0.00 0.0 0 18.5 32 230 M M 4 40 270
7 32 25 29 -4 36 0 0.02 0.6 T 12.6 21 240 M M 10 8 27 250
8 33 19 26 -6 39 0 T T T 13.9 25 210 M M 4 30 210
9 30 24 27 -5 38 0 0.10 1.5 T 9.0 18 200 M M 10 8 23 200
10 30 24 27 -5 38 0 T T 1 12.3 23 220 M M 9 27 220
11 31 24 28 -3 37 0 0.27 3.8 4 5.0 14 310 M M 10 18 20 310
12 32 16 24 -7 41 0 0.01 0.2 4 14.9 29 310 M M 8 169 36 330
13 26 14 20 -11 45 0 0.42 6.3 4 9.6 21 10 M M 10 129 27 10
14 21 10 16 -14 49 0 0.01 0.2 9 8.4 16 360 M M 6 89 19 350
15 28 16 22 -8 43 0 0.01 0.3 7 11.8 24 220 M M 10 29 240
16 36 21 29 -1 36 0 0.02 0.7 7 9.3 17 220 M M 10 8 23 220
17 36 21 29 0 36 0 0.00 0.0 6 6.0 12 70 M M 9 18 15 70
18 41 30 36 7 29 0 0.01 0.0 5 12.5 20 230 M M 10 18 23 240
19 48 37 43 14 22 0 0.00 0.0 T 15.1 23 240 M M 6 28 230
20 38 28 33 4 32 0 0.00 0.0 T 6.5 22 300 M M 5 29 310
21 35 28 32 4 33 0 T 0.0 0 7.5 16 70 M M 10 22 60
22 36 33 35 7 30 0 T 0.0 0 5.3 15 70 M M 10 18 20 70
23 37 28 33 5 32 0 0.07 0.7 0 7.9 17 310 M M 8 1 23 300
24 28 20 24 -4 41 0 0.34 4.4 1 8.0 17 290 M M 10 1 20 290
25 22 11 17 -11 48 0 0.03 1.0 5 15.8 29 250 M M 8 189 36 260
26 14 3 9 -18 56 0 0.02 0.7 6 8.1 18 250 M M 9 19 22 250
27 13 -4 5 -22 60 0 0.00 0.0 5 7.0 16 320 M M 3 18 19 280
28 14 -3 6 -21 59 0 0.04 1.2 5 3.7 9 170 M M 7 18 11 170
29 19 10 15 -12 50 0 0.05 0.6 6 9.2 17 250 M M 9 18 20 230
30 17 4 11 -16 54 0 0.02 0.3 6 11.3 22 290 M M 7 18 31 280
31 17 2 10 -16 55 0 0.00 0.0 6 5.0 10 300 M M 6 13 330
================================================================================
SM 1023 626 1181 0 1.48 22.5 302.1 M 245
================================================================================
AV 33.0 20.2 9.7 FASTEST M M 8 MAX(MPH)
MISC ----> # 32 240 # 45 210
================================================================================
PRELIMINARY LOCAL CLIMATOLOGICAL DATA (WS FORM: F-6)
STATION: DETROIT MI
MONTH: JANUARY
YEAR: 2018
LATITUDE: 42 13 N
LONGITUDE: 83 20 W
TEMPERATURE IN F: :PCPN: SNOW: WIND :SUNSHINE: SKY :PK WND
================================================================================
1 2 3 4 5 6A 6B 7 8 9 10 11 12 13 14 15 16 17 18
12Z AVG MX 2MIN
DY MAX MIN AVG DEP HDD CDD WTR SNW DPTH SPD SPD DIR MIN PSBL S-S WX SPD DR
================================================================================
1 13 -2 6 -20 59 0 T T 6 9.2 24 290 M M 9 18 32 280
2 13 0 7 -19 58 0 T T 6 15.3 22 210 M M 8 26 220
3 17 0 9 -17 56 0 0.01 0.5 6 13.4 21 220 M M 10 1 26 220
4 17 1 9 -17 56 0 T T 6 10.9 21 300 M M 6 8 26 330
5 6 -4 1 -25 64 0 0.00 0.0 6 10.8 23 300 M M 1 8 29 330
6 10 -5 3 -23 62 0 0.00 0.0 6 5.5 15 320 M M 2 20 330
7 30 -6 12 -14 53 0 0.01 0.2 6 12.3 24 210 M M 9 31 210
8 37 29 33 7 32 0 0.24 2.2 8 14.7 22 230 M M 7 149 28 250
9 37 25 31 5 34 0 0.00 0.0 6 6.6 13 170 M M 6 18 16 250
10 46 25 36 10 29 0 0.08 T 6 6.9 16 180 M M 9 16 19 180
11 57 43 50 24 15 0 0.02 0.0 2 14.6 22 170 M M 10 1 27 170
12 55 14 35 10 30 0 0.19 0.7 0 17.1 28 360 M M 10 146 38 360
13 19 11 15 -10 50 0 T T 1 10.1 26 340 M M 7 35 330
14 20 8 14 -11 51 0 T T 1 5.8 17 200 M M 8 20 160
15 22 15 19 -6 46 0 0.06 1.9 T 7.3 15 140 M M 10 1 19 130
16 22 7 15 -10 50 0 T 0.2 2 11.1 16 230 M M 10 18 18 230
17 24 2 13 -12 52 0 T 0.1 2 11.9 24 220 M M 7 18 31 230
18 28 13 21 -4 44 0 0.00 0.0 2 16.4 21 230 M M 5 29 230
19 36 21 29 4 36 0 0.00 0.0 1 17.2 29 220 M M 4 36 220
20 43 31 37 12 28 0 0.00 0.0 1 12.6 24 230 M M 7 34 230
21 42 33 38 13 27 0 T 0.0 T 2.8 12 180 M M 10 12 14 170
22 55 38 47 22 18 0 0.40 0.0 0 7.2 22 190 M M 10 12 26 190
23 47 29 38 13 27 0 0.12 0.0 0 16.2 29 210 M M 10 13 36 240
24 30 25 28 3 37 0 T T 0 6.5 17 310 M M 10 8 22 310
25 35 25 30 5 35 0 T 0.0 0 6.7 16 200 M M 8 1 19 200
26 53 27 40 15 25 0 0.00 0.0 0 11.6 26 200 M M 4 32 200
27 50 31 41 16 24 0 T 0.0 0 17.4 30 210 M M 8 39 220
28 47 27 37 11 28 0 0.00 0.0 0 5.6 17 60 M M 4 23 50
29 31 18 25 -1 40 0 0.23 3.4 T 12.3 22 360 M M 10 12 27 10
30 23 13 18 -8 47 0 T T 3 8.5 15 280 M M 9 M M
31 41 22 32 6 33 0 0.00 0.0 3 15.4 31 220 M M 10 37 220
================================================================================
SM 1006 516 1246 0 1.36 9.2 339.9 M 238
================================================================================
AV 32.5 16.7 11.0 FASTEST M M 8 MAX(MPH)
MISC ----> # 31 220 # 39 220
==============================================================================
Looking
at the analogues the past few months and their predominant temperature
and snowfall prognostications below; served us very well thus far this
winter. I already blogged about December's actual and projected numbers and performance, therefore let's check January to give an idea how I check performance.
Looking at the top temperature chart (below) we see basically January's actual temperature average mirrored the analogues projections.
First off, January's analogue temperature projections were more mixed
and evenly divided though; still had a slight biased to colder than
average /-1.1/. This was less of a departure than Decembers predominately below normal
projections and results. December's prevailing colder than normal numbers and the average is depicted in blue on this chart. On
it's performance, I used the below normal average added to the general
average of all the 14 Decembers and divided by two to be fairer in using
all the set of analogues.
This therefore, gives the weighting to the strongest forecast
indicators but still accounts for all the data in the analogue temperature
forecast.
Since January's set of analogues contained seven below and seven above; I use the usual mean of all those numbers as a comparison number since neither was dominant. The average of all the January analogues came in at 24.5, or
-1.1 below the January norm average of 25.6. Outstandingly, this
January's average came in nearly identical to that projected number - 24.6! You will fine the average
for all the January temperature years and the January 2018 actual
temperature (the white number at the bottom) in the January column.
January’s actual snowfall (above) for Detroit /9.2"/ was 1 1/2" below the mean average of all the analogues at 10.7" (and also below the norm of 12.5"). Since snowfall amounts have such a wide potential outcome down to the tenths, I’m more concerned with the trend found rather than the actual number above or below. I check the performance by first waiting for the actual number for the month and then, compare
its respective category (above, below, normal) it falls into from the
analogue s set. I consider the predominant trend found -in this case below normal- and lean more heavily on that and less at the actual number. If we add all the predominant below
normal January snows and divide by the number of below (nine) we get
6.0”; lower than the actual number of 9.2” and quite a bit lower than the actual norm of 12.5”.
Therefore; snow or rainfall projections in the analogues are handled mainly as prevailing trends and secondary to the actual number.
Outlook
Well, why this is fine and dandy for the past - what about the future, the rest of the winter into mid spring? On the surface it looks as though analogues, models and even the ground hog all agree on six more weeks winter into mid March anyway.
A quick glance at the analogues pretty much continues the trend with a slight edge /-0.7/ to normal to below normal temperatures (albeit via roller-coaster) through February. Then; a more mixed opinion for March (warmer with nine above) and April (colder with nine below). March's data is extraordinarily wide ranging and speaks volumes for what March is known for: wild with big temperature gyrations! Analogue March temperature ranges(*) from 29.3 to 50.7! Anyone recall that March of 2012 with that exceptionally warm average of 50.7? The transition seasons as I call them (Spring, Autumn) generally a more difficult to peg because of timing issues between Winter and Summer and also associated big temperature fluctuations.
In my original Winter Outlook; I went with a decidedly colder trend for the overall winter with temperatures averaging normal to below (up to 3.0 degrees below). Thus far through January; Detroit is averaging close to 2 1/2 degrees below normal.
Snowfall and rainfall continue the below normal trend (Detroit area) for February in the analogues but with a pick up somewhat in March and April. As noted however; snowfalls for the entire season across Southeast Lower Michigan came in around normal (within 5" of the norm - 43.4") from the metro Detroit area south to Ohio - and above normal from the north/northwest suburbs into Flint and Port Huron. Earlier projections of above normal snows for the Saginaw Valley doesn't look likely unless that region receives a some good snowfalls.
It must be noted however; though the trend is for below normal snows in the analogues in February for the Detroit area there were some hefty snows as outliers in both February and March. In addition, this season looks to have the appearance of a snowier beginning with a snowier end - occasionally seen with the front/back end loaded winters /U shaped/. The later part of the winter into early spring is notorious for that as more moisture returns to the region from the south. As with all projections besides trends, timing issues can cause problems with overall cold/wet or warm/dry trends overlapping months.
_____ Analogues into Spring
_______Computer projections for the remainder of winter into spring.
Note the resilient prevailing blocking pattern set up for February. Impressive troughing appears to be reloading over eastern Canada and occasionally pushing well south into the eastern US.
____________CFS Model Projections
Current CFS model projects a colder and drier February (total precipitation, not necessarily snowfall).
Current CFS model projects a colder and drier February (total precipitation, not necessarily snowfall).
March (below) holds on to normal to below for temperatures while precipitation is normal to above. The last two maps reflect the three month temperature period and prevailing upper air pattern. The huge trough over eastern Canada meanders further east with time.
Making weather fun while we all learn,Bill Deedler -SEMI_WeatherHistorian
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