May 2021 Boards weather forecast contest

As mentioned, 06z GFS (from last night) is used to assess "normal" bonus answer from 552 dm thickness line which first impacts Ireland on 13th.

Hence this is the NormaL entry:

11.0 _ 24.5 _ -1.0 _ 100 _ 100 _ 13th

Table of forecasts for May 2021


FORECASTER ___ (pen) ____ IMT _ MAX _ MIN _ PRC _ SUN __ Next 21.2+


Danno __________________ 12.1 _ 23.6 _ -2.8 _ 120 _ 110 ___ 30th

Tae laidir ________________11.6 _ 25.0 _ -1.5 _ 118 _ 095 ___ 20th

Joe Public _______________ 11.5 _ 25.5 _ -1.5 _ 110 _ 099 ___ 15th

john mac ________________11.2 _ 23.9 _ -1.6 _ 103 _ 102 ___ 23rd

WesternStorm ____________11.1 _ 24.0 __ 0.0 _ 121 _ 092 ___ 10th

Dasa29 _________________ 11.0 _ 24.5 _ -2.0 _ 110 _ 110 ___ 20th


___ NormaL ______________11.0 _ 24.5 _ -1.0 _ 100 _ 100 ___ 13th


Jpmarn _________________ 10.9 _ 25.7 _ -2.5 _ 070 _ 120 ___ 13th

Kindred Spirit ____ (-1) ____ 10.9 _ 23.7 _ -1.4 _ 140 _ 095 ___ 18th

Mr stonewall _____________ 10.9 _ 23.2 _ -1.6 _ 115 _ 093 ___ 19th

M.T. Cranium ____________ 10.8 _ 24.7 _ -1.5 _ 150 _ 083 ___ 16th

Dacogawa _______________10.8 _ 24.7 _ -1.8 _ 142 _ 087 ___ 14th

Artane2002 ______________10.8 _ 23.3 _ -1.8 _ 125 _ 085 ___ 16th


___ Con Sensus __________ 10.8 _ 23.6 _ -1.8 _ 120 _ 095 ___ 20th


Bsal ____________________10.7 _ 23.5 _ -2.0 _ 110 _ 094 ___ 18th

Mr Skinner ______________ 10.6 _ 25.6 _ -2.3 _ 090 _ 095 ___ 22nd

waterways _______________10.6 _ 25.2 _ -3.2 _ 128 _ 092 ___ 25th

CirrusBusiness ___________ 10.6 _ 23.2 _ -1.8 _ 135 _ 085 ___ 26th

DOCARCH _______________10.6 _ 22.3 _ -1.8 _ 095 _ 108 ___ 12th

Gonzo _________ (-5) _____10.4 _ 22.6 _ -3.2 _ 136 _ 086 ___ 23rd

200 motels _____ (-5) _____10.4 _ 21.0 _ -1.3 _ 111 _ 079 ___ 20th

sryanbruen ______________10.3 _ 22.9 _ -1.1 _ 130 _ 075 ___ 19th

Sunflower3 ______________10.2 _ 23.4 _ -2.2 _ 090 _ 095 ___ 21st

Appledrop _______________10.2 _ 22.2 _ -3.0 _ 120 _ 085 ___ 23rd

Adam240610 ____ (-4) ____10.1 _ 23.7 _ -2.5 _ 120 _ 095 ___ 20th

Pauldry _________________ 9.8 _ 22.5 _ -2.3 _ 125 _ 090 ___ 22nd

__________________________________________

Two points were added to late penalties if a value below -2.5 C was submitted for MIN

... this is to equalize scoring advantage from the discussion, a larger penalty would be unfair because anyone

had the option of waiting to 0200h to make a reasonably informed forecast.

... anyone who did not appear to benefit from their late submission is not given an extra 2 points late penalty.

___________________________________________

The dates selected for the next temp above 21.2 C ...

10 12 13 14 15 16 16
18 18 19 19 20 20 20 20
21 22 22 23 23 23 25 26 30

If the actual day falls in the middle range above then scores will be 10 minus error of days but with some increase for largest errors

If the actual day is at either end of this range then we'll go with some system of groups of three.

24 forecasts so far, would imagine that might be all this month, but if any really late ones appear, choose either the MIN we know (with this big a late penalty, will just cap the score at 16) or take some lower value if you think it could verify, within 0.4 subject to slight cap also.

After the first week ...

IMT 6.5 C which is 3.8 below normal. That is probably around 7.4 now though.

MAX will be today's value, will edit that in tomorrow (18-19)

MIN was -4.0 and so scoring has already taken place (see previous post).

PRC was 145% at midnight but another 10-15 mm fell earlier today, getting week two off to a healthy start. The amounts so far would probably equate to half the average monthly total.

SUN has made a good start at 130% (878/600).

I hear there's a popular park in Beijing called Phone-Xi park.

After two weeks ...

IMT is 8.3, second week was 10.2 C, still 0.7 below normal for 8th to 14th. Today's 12z GFS run gives some hope for warming in the fourth week, we will likely still be close to 8.5 by then, and could then steadily rise towards 10.5 or a bit higher for the outcome. However, some recent runs have not been as optimistic and we would struggle to reach even our lowest IMT forecast of 9.8.

MAX was 19.2, MIN -4.0 and already scored as that was below all forecasts. MAX likely won't change this coming week but could go into the 20s eventually.

PRC is now 170% with the second week a soaking 194% of normal. Third week looks about as wet as we've had it so far, then fourth week a bit drier, outcome could be around 140%. Only three forecasts went that high (I went 150%, dacogawa 142%, Kindred Spirit is at 140% and sryanbruen at 130%). There could be a "modified minimum progression" situation developing unless there is so much rain that it blows past 157% (then my raw score drops to 12 or below and full boost kicks in). No big gaps below 150% so somebody would trigger the reduced version for sure.

SUN finally took some time off, in some places anyway, and is now at 113% with the second week at 96% (574/600), mainly due to Valentia being quite cloudy, the other five locations averaged about 110%. This coming week looks quite cloudy but the fourth week at least on today's model run looks more average. The net change would be back down towards 100%, possibly lower. Our lowest forecast was 75% and our highest 120%.

On the matter of the bonus question, the one day we had any chance of breaking 21.2 was last Saturday and that fell short, the next opportunity from today's model run and using the 552 dm thickness modified by solar angle now to 549 dm, appears to be ... calculating here ... 24 May. (omg) If so, that would fall into third last place in the table of guesses (we have a 26th and a 30th, several said 23rd and would share the ten points if this verifies, or even if it's 25th, at 26th I think I would go 10 for the 26th guess and 9 for all of the 23rd and 30th guesses and work down from there to be fair. Of course, that's today's revised version of the model run, I check them daily for the forecasting and they have been bouncing back and forth for days now between no warming trend at all to a considerable warming after the 23rd, no hunch as to which is correct. If we go later than 26th then 26th and 30th will get ten, the 23rds will get 9, etc.