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Roger J Smith

March 2018 C.E.T. forecasts and optional EWP contest

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Posted (edited)
4 hours ago, Scorcher said:

Yes but looking at the model output I just can't see how it's sustainable this time. We need really exceptional 850 hPa temps at this time of year to deliver the sort of spell that would get us under 3C.

Defintely a possibility, the coldest ensemble member of the 06z (p13) for example has a CET of around 2.3C by the 29th (lets assume the final CET will have 0.2C knocked of it with the adjustments).

Such runs aren't without support but I think the more likely scenario is a CET of around 3.5C come the end of the month, maybe a bit higher if the westerlies return.

Edited by Quicksilver1989

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6 hours ago, Scorcher said:

Yes but looking at the model output I just can't see how it's sustainable this time. We need really exceptional 850 hPa temps at this time of year to deliver the sort of spell that would get us under 3C.

Uppers are looking lower than they were in 2013 if my memory serves me correctly.

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The 06z GFS would have the CET at about 4.5C to the 17th.
Assuming that's somewhat accurate, these are the averages required for the remainder of the month to reach particular values.

3.5C to reach 4.0C
2.4C to reach 3.5C
1.3C to reach 3.0C
0.2C to reach 2.5C
-1.0C to reach 2.0C

Given that the coldest final 14 days of March on record is 1.3C from 1837, I think we can largely rule out anything below 2.5C after corrections.

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3.6c here to the 12th, 1.4c below the 1981-2010 average.

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Sunny Sheffield up to 2.4C -2.6C below normal. Rainfall 69.1mm 108.5% of average Temp should keep rising until Saturday So Expecting to be around 3.8C at that time.

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9 hours ago, Relativistic said:

Uppers are looking lower than they were in 2013 if my memory serves me correctly.

There are no signs of them being sustained though- the key to 2013 being so cold was the fact the cold was sustained and not so much the extreme uppers. We only had one ice day here in the whole of March 2013. So the recent cold spell was more potent than anything in March 2013, but it was very short in comparison to what we had back then. There was also no mild spell in the month as we've had this time around.

By midweek next week the GFS shows uppers going back towards average.

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4.1 to the 13th

1.1 below the 61 to 90 average

1.8 below the 81 to 10 average

________________________________

Current high this month 4.1 to the 13th

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Milder GFS runs so far today. The 06z would have the CET dipping to just 4.2C before climbing once more toward the end of the high res section (yesterday we were reaching the high 3s before climbing).

I'll do a full update later for the 12z.

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Sunny Sheffield up to 2.8C -2.3C below normal. Rainfall unchanged from yesterday.

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Here's the forecast based on the 12z GFS

Rolling CET... Anomaly to 81-10 rolling avg (Daily Avg: Anomaly to 81-10 daily avg)

4.2C to the 14th... -1.7 (6.3: -0.3)
4.6C to the 15th... -1.4 (9.3: +2.3)
4.8C to the 16th... -1.2 (8.8: +1.9)
4.7C to the 17th... -1.5 (2.1: -5.4)
4.4C to the 18th... -1.8 (-0.7: -7.8) [Record low is -1.3C from 1853]
4.2C to the 19th... -2.0 (1.7: -4.9)
4.2C to the 20th... -2.1 (2.9: -3.7)
4.1C to the 21st... -2.1 (3.8: -2.8)
4.1C to the 22nd... -2.1 (4.0: -2.9)
4.2C to the 23rd... -2.1 (5.1: -1.8)

A couple of mildish days on the horizon before the cold weather returns. At this stage I'd say a lower limit of 3.0C before corrections, with an upper limit of around 6.0C, so quite a spread possible as we near the mid month mark. 

C2fo0LF.jpg

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4.2 to the 14th

0.9 below the 61 to 90 average

1.7 below the 81 to 10 average

________________________________

Current high this month 4.2 to the 14th

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Running similar to the CET here despite being North of the zone.

Currently 4.1c here to the 14th, 1.0c below the 1981-2010 average.

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Sunny Sheffield at 2.9C -2.2C below normal. Today much cooler than expected so a smaller rise tomorrow. Rainfall at 69.3 108.8% of normal.  The weekend should cancel most of this weeks mild weather out next week not looking mild with ground frosts and possible air frosts so despite double figures being reached later on it's look they'll be a good daily temperature range. This if of course the GFS is correct. 

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At the half way stage, and a colder than average March looks more likely than a milder than average one, next few days will return very cold CET values, becoming only average next week, so we will be going into the last third significantly below average I suspect, and I don't foresee a late warm up. Chance could end up 1 degree below 61-90 average, quite notable given most March's last 10 years have been mild or very mild, exception the exceptional March of 2013.

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4.5 to the 15th

0.7 below the 61 to 90 average

1.5 below the 81 to 10 average

________________________________

Current high this month 4.5 to the 15th

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Here's the forecast based on the 06z GFS

Rolling CET... Anomaly to 81-10 rolling avg (Daily Avg: Anomaly to 81-10 daily avg)

4.8C to the 16th... -1.2    (8.9: +2.0)
4.5C to the 17th... -1.6    (0.3: -7.2)
4.3C to the 18th... -1.9    (-0.3: -7.4)
4.1C to the 19th... -2.1    (1.3: -5.3)
4.1C to the 20th... -2.1    (3.7: -2.9)
4.1C to the 21st... -2.2    (3.6: -3.0)
4.2C to the 22nd... -2.1    (6.9: +0.0)
4.4C to the 23rd... -2.0    (7.6: +0.7)
4.4C to the 24th... -1.9    (6.0: -1.4)
4.5C to the 25th... -1.9    (6.2: -1.1)

A steep drop over the next few days, followed by a gradual raise. An impressive drop in the daily CET values between today and tomorrow seems likely. Will have a look at what record drops have occurred from one day to the next in the March CET later.

U2EYpdr.jpg

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Sunny Sheffield up to 3.1C -2.1C below normal. Rainfall 74.7mm 117.3% of normal. Another smaller rise temp wise tomorrow and probably back to down to 2.8C by Monday.  

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Posted (edited)

Sunny Sheffield up to 3.4C -1.9C below normal. Rainfall 79.7mm 125.1% of normal. Bigger rise than I expected but big drops for the next few days.

Edited by The PIT

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After a quick look, the top 3 largest drops for the CET from one day to the next in March are:

8.5C from the 28th in 1777
8.5C from the 4th in 1821
7.5C from the 25th in 1858

It will be interesting to see how the drop from yesterday to today compares!

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4.8 to the 16th

0.4 below the 61 to 90 average

1.3 below the 81 to 10 average

________________________________

Current high this month 4.8 to the 16th

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These are the ten coldest final fifteen days (one way of saying second half) of March (17th to 31st), with the values for the full month of March, and the rest of the year and following winter added:

Will be interesting to see if 2018 can crack this list (based on daily data 1772 to 2017, probably coldest March 1674 (1.0) would be on this list if we had daily data then. So I have included 1674 for the after-comparisons. No other March before 1772 averaged colder than 2.0 except 1748 (1.8) with 1667 at 2.0 (plus or minus 0.5) which I also added to the table, but that does not mean that none of the other years would have made the list. 

 

rank _ YEAR __ CET 17-31 _MAR _ APR_ MAY _JUN _ JUL _AUG _ SEP_ OCT _ NOV _ next winter

_01 __ 1837 ___ 1.39 ______ 2.3 __ 4.7 __ 9.9 _ 15.5 _ 16.9 _ 15.7 _ 12.5 _ 10.5 __ 5.2 ___5.3,-1.5,0.4

_02 __ 2013 ___ 1.62 ______ 2.7 __ 7.5 _ 10.4 _ 13.6 _ 18.3 _ 16.9 _ 13.7 _ 12.5 __ 6.2 ___ 6.3,5.7,6.2

_03 __ 1853 ___ 1.74 ______ 3.4 __ 7.6 _ 10.9 _ 14.3 _ 14.9 _ 14.7 _ 12.3 _ 10.1 __ 5.2 ___ 1.3,3.6,4.3

_04 __ 1785 ___ 1.88 ______ 1.2 __ 8.4 _ 12.3 _ 16.1 _ 16.1 _ 13.9 _ 13.6 __ 8.7 __ 5.6 ___ 2.8,2.7,3.4

_05 __ 1883 ___ 1.95 ______ 1.9 __ 8.1 _ 10.6 _ 13.9 _ 14.5 _ 15.3 _ 13.3 __ 9.7 __ 5.8 ___ 4.6,6.5,5.3

_06 __ 1919 ___ 2.14 ______ 3.6 __ 7.1 _ 13.5 _ 14.3 _ 13.9 _ 15.7 _ 12.7 __ 7.4 __ 3.3 ___ 5.5,5.2,6.0

t  07__ 1786 ___ 2.21 ______ 2.1 __ 8.1 _ 11.2 _ 16.1 _ 15.0 _ 15.1 _ 11.7 __ 7.5 __ 3.3 ___ 2.8,3.6,5.9

t  07__ 1808 ___ 2.21 ______ 3.2 __ 5.8 _ 13.7 _ 14.8 _ 18.4 _ 16.7 _ 12.7 __ 7.2 __ 6.0 ___ 2.2,2.0,5.7

_09 __ 1865 ___ 2.31 ______ 2.9 _ 10.6 _ 12.6 _ 15.6 _ 16.6 _ 15.1 _ 16.3 __ 9.7 __ 6.7 ___ 5.8,5.8,4.4

_10 __ 1789 ___ 2.49 ______ 2.1 __ 7.4 _ 12.5 _ 14.0 _ 15.4 _ 16.6 _ 13.1 __ 8.6 __ 4.6 ___ 6.1,4.3,6.6

mean of data following year __2.4 __ 7.5 _ 11.8 _ 14.8 _ 16.0 _ 15.6 _ 13,2 __ 9.2 __ 5,2 ___ 4.2,3.8,4.8

(no daily data before 1772) _ most likely candidates ...

_?? __ 1674 ___ ??? ______ 1.0 __ 7.5 _ 11.0 _ 13.5 _ 14.0 _ 13.5 _ 10.5 __ 9.0 __ 6.5 __ 3.5,3.0,2.0

_?? __ 1748 ___ ??? ______ 1.8 __ 6.3 _ 10.4 _ 14.8 _ 15.4 _ 15.8 _ 14.2 __ 9.2 __ 7.1 __ 6.0,5.3,3.6

_?? __ 1667 ___ ??? ______ 2.0 __ 7.0 _ 10.0 _ 15.0 _ 17.0 _ 16.0 _ 13.0 __ 9.0 __ 6.0 __ 3.0,5.0,5.0

_____________________________________________________________________________________

ANALYSIS:

The coldest value from 1922 (2.91) to 2013 (1.62) was 3.76 in 1962. If 2018 makes this list, it would be the first time since 1786 or 1789 (which would be off the top ten list) that a year made this list within 5 years of the previous time -- 1789 had waited just three years and 1786 followed 4th place 1785. The other intervals would then be 22 years, 29 years, 16 years, 12 years, 18 years, 36 years and 94 years (1919 to 2013). 

The year following these cold second halves of March follow a general pattern -- steady warming in April to somewhat above normal May-Junes, then a coolish average sort of summer with more very cool months than very warm ones, and a rather cold autumn followed by an increasingly mild winter the next year. That pattern generally fits the three years added as well as 1799 and 1917 which did not make the list but turned very cold at the end of March. The pattern following 1962 was generally cold and of course very cold (like winter 1837-38) the next winter. 

Of course there is no guarantee that 2018 will make this list but it looks to have a chance given the number of cold days including the 17th already in the books. 

Summers of 1808 and 2013 give some cause for optimism about summer, it can be a warm one following this type of early spring although the odds seem more in favour of a cool, wet summer. 

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5 hours ago, Roger J Smith said:

 

The year following these cold second halves of March follow a general pattern -- steady warming in April to somewhat above normal May-Junes, then a coolish average sort of summer with more very cool months than very warm ones, and a rather cold autumn followed by an increasingly mild winter the next year. That pattern generally fits the three years added as well as 1799 and 1917 which did not make the list but turned very cold at the end of March. The pattern following 1962 was generally cold and of course very cold (like winter 1837-38) the next winter. 

I for one hope that this March is followed by a below average Winter like 1837 and 1962. Although this didn't happen in 2013 and it seems that based on this milder Winters more often follow these cold March's than colder ones. Although in 2013 weren't we heading away from solar minimum, whereas now we're heading towards it? Not that I'm naive enough to assume that solar conditions dictate the type of season we get exclusively, but I'm at least hoping it does us some favours and at least gives us cause for optimism.

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I see similarities to 1996 this year, similar in the solar level too. That was a good summer- good sunshine levels and a little above average temps. The following winter was cold, especially early

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We had a run of generally below average months leading up to that record cold March 2013,  the following July was a protracted hot and sunny period for weeks on end , and it was like a switch being flicked , the following months where all above average, and the the following winters where all mild , perhaps this year the the switch been turned off again  

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