May 2021 Boards weather forecast contest

M.T. Cranium

1. Predict the IMT (11.0 is the average 1981-2010 value).

2. Predict the MAX at 25 met.ie locations reporting in "yesterday's weather" each day on their website.

3. Predict the MIN at 25 met.ie locations reporting in "yesterday's weather" each day on their website.

4. Predict the PRC as percentage of normal at a grid of eleven stations.

5. Predict the SUN as percentage of normal at a grid of six locations.

6. BONUS _ As it appears the April maximum was 21.2 on the first (at Valentia) predict the first (or next) date with a higher temperature than that. If your MAX for May happens to be below 21.2, just give June 1st as your prediction (I don't expect many to choose this option). No location or value is required. Guaranteed point insurance on this, if a large number choose similar dates, then the point allocation will be top to bottom but cannot fall by more than one per day. (I'm setting up this potential juicy bonus points pool to offset the difficulty posed by this month). Normal for the bonus will be set at first day with a 552 dm thickness contour in Ireland on the 0600z May 1st GFS model run.

That being the case I will hold off with NormaL predictions until around then, but mine are here:

MTC __________ 10.8 _ 24.7 _ -1.5 _ 150 _ 083 __ 16th

Note: any late entries quoting an already set MIN on 1st could be docked points in the MIN scoring as well as the late penalty that applies.

The usual late penalties are in play after 0300h Saturday May 1st. (May day, may day)

pauldry

Pauldry__________ 9.8 _ 22.5 _ -2.3 _ 125 _ 090__ 22nd

sryanbruen

sryanbruen __________ 10.3 _ 22.9 _ -1.1 _ 130 _ 075 __ 19th

CirrusBusiness

CirrusBusiness______10.6_23.2_-1.8_135_085_26th

Joe Public

Joe Public __________ 11.5 _ 25.5 _ -1.5 _ 110 _ 099 __ 15th

Bsal

Bsal __________ 10.7 _ 23.5 _ -2.0 _ 110 _ 094 __ 18th

dasa29

Dasa29 __________ 11.0 _ 24.5 _ -2.0 _ 110 _ 110 __ 20th

Artane2002

Artane2002__________ 10.8 _ 23.3 _ -1.8 _ 125 _ 085 __ 16th

Tae laidir

Tae laidir _______ 11.6 _ 25.0 _ -1.5 _ 118 _ 95 __ 20th

DOCARCH

DOCARCH ______ 10.6 _ 22.3 _ -1.8 _ 095 _ 108 __ 12th

mr.stonewall

Mr stonewall___10.9__23.2__-1.6__115__93__19th

appledrop

Appledrop 10.2___22.2___-3.0___120%___85%__23rd

waterways

waterways __________ 10.6 _ 25.2 _ -3.2 _ 128 _ 092 __ 25th

mrskinner

Skinner____10.6____25.6____-2.3____90____95____22nd

sunflower3

Sunflower3 ______ 10.2 _ 23.4 _ -2.2 _ 090 _ 95 __ 21st

John mac

john mac __________ 11.2 _ 23.9 _ -1.6 _ 103 _ 102 __ 23rd

Danno

Danno __________ 12.1 _ 23.6 _ -2.8 _ 120 _ 110 __ 30th

WesternStorm

WesternStorm __________ 11.1 _ 24.0 _ 0.0 _ 121 _ 092 __ 10th

dacogawa

Dacogawa ________ 10.8 _ 24.7 _ -1.8 _ 142 _ 087 __ 14th

Jpmarn

Jpmarn __________ 10.9_ 25.7 _ -2.5 _ 70 _ 120 __ 13th

kindredspirit

Kindred Spirit ___ 10.9 ___ 23.7 ___ -1.4 ___ 140 ___ 95 ___ 18th

appledrop

May here we go!

Looks like it got to -2 early this morning at DA and Dunsany. We will have to wait for official data tomorrow.

adam240610

Adam240610 10.1__ 23.7__-2.5__120 __ 095__ 20th

pauldry

-2.1c at midnight in Dunsany so May min definitely below that

Gonzo

Gonzo ___ 10.4 ___ 22.6 ___ -3.2 ___ 136% ___ 86% ___ 23rd

M.T. Cranium

I won't add any extra penalties to those late guesses since none of them had enough precise information available to guarantee a result, and colder nights could follow. Will make up a table of forecasts tomorrow as I suspect one or two more could appear. That extra penalty would apply if one of those quoted a "revealed" value (and it held up, the extra penalty would be withdrawn if a colder value lowered the score anyway).

appledrop

Looks like it got down to -2.7 at Dunsany last night according to Met Eireann twitter, we will know for certain tomorrow.

200motels

200 motels 10.4 _ 21 _ -1.3_ 111_ 79__ 20th

M.T. Cranium

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

Tae laidir

Dunsany -2.7 confirmed.

M.T. Cranium

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.

Tae laidir

Markee Castle -2.7 again yesterday.

pauldry

Met Eireann forecasting -3c Wednesday night so could possibly go lower again.

appledrop

pauldry wrote: »

Met Eireann forecasting -3c Wednesday night so could possibly go lower again.

Pauldry could you ask Met Eireamn to arrange it to be -3 exactly?

I might get some points then this month after my dismal score of nil points for my min prediction last month!

appledrop

Mt Dillion -4 at 6am.

M.T. Cranium

Looks like I could score MIN already on the 6th LOL. Minimum progression required. Will retain the 2 point augmented late penalties as there probably was a slight advantage and the two people getting that will be scoring well on MIN.

Will go with 20, 20, 19, 18 etc, doubling up also at 15, 10 and 5, that should get us down to 1 point for mildest forecast. Ties may make it a bit uneven and I may even things out where the values are not evenly spaced, wait and see on that but otherwise you can pretty much figure out your MIN score now.

Gonzo and waterways (-3.2) to get 20 (Gonzo really 18 due to the augmented late penalty).

Appledrop (-3.0) 19, Danno (-2.8) 18, adam240610 (-2.5) 17 (net 15) JPmarn (-2.5) 17.

MrSkinner (-2.3) 15, Pauldry (-2.3) 15, sunflower3 (-2.2) 14, dasa29, bsal (-2.0) 13.

Artane2002, DOCARCH, dacogawa, Cirrus Business and consensus, (all -1.8) 11.

MrStonewall (-1.6), john mac (-1.6) 8.

M.T.Cranium, tae laidir, Joe Public (all -1.5) 6.

Kindred spirit (-1.4) 4, 200motels (-1.3) 3.

sryanbruen (-1.1) 2, NormaL (-1.0) 2, western storm (0.0) 1.

Jpmarn

The -4°c report in Roscommon (Mt Dillon) was mentioned on the Radio 1 7.55 weather forecast.

DOCARCH

Mount Dillon confirmed at -4.0c yesterday.

pauldry

Yes and that will likely be it for May.

Tomorrow 18c!!

M.T. Cranium

Full weekly report tomorrow but IMT on 6.6 after six days, and yesterday's average was 4.9, about normal for this time in Jan or Feb.

Jpmarn

pauldry wrote: »

Yes and that will likely be it for May.

Tomorrow 18c!!

19°c has been indicated for the Dublin area on the TV after the RTÉ ONE 9 O’clock News.

M.T. Cranium

There appears to be a fairly wide "dry slot" so there may be enough sunshine to boost temperatures to 21.3 and end the suspense -- that 552 dm thickness is making a brief visit. Another scoring task ending ahead of schedule? We shall find out. Would suspect Gurteen or Moorepark might do the business as they will have longer intervals of sunshine possibly.

appledrop

It's currently lashing rain and 6 degrees at Dublin airport.

However it is meant to take up so who knows what will happen.

It is reading 13 degrees at 7am at Moorepark , if that is correct.

appledrop

Turned into a beautiful day eventually in Dublin.

Maxed out at about 18 degrees so April max is not beaten yet.

Great to actually feel the heat of the sun again!

M.T. Cranium

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).

appledrop

19.2 new Max on 8th at Phoneix Park.

M.T. Cranium

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

M.T. Cranium

Looking ahead it's hard to see where it would get any warmer now, the IMT may drift up slowly with the cloudy nights but daytime highs are going to remain in a fairly low range now. If that was the month's high then good old Minnie Progression may get another call.

M.T. Cranium

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.

M.T. Cranium

Rules for minimum progression. I think these were spelled out once or twice over the years, worth repeating them for general interest.

(1) Minimum progression is used only when one-third or more of the contest entrants score zero, or when the entire run of scores is lower than usual. The normal application is to take the best forecast and award that one maximum points or one fewer if the forecast scores zero. Then the rest of the field are awarded points in rank order with one point the end of the progression unless the start is one short, then zero is the end point.

(2) If these conditions apply but one or more forecasters have raw scores within two of the maximum allowed in the category, then "reduced minimum progression" is used, that being the same as above, compared to raw score, and an average taken. (example, in normal minimum progression the forecast would score 10, the raw score was 2, then the reduced minimum progression score is 6).

(3) Contest scorer has the option of modifying the progression to fit any discontinuous run of forecasts for fairness, for example, if there were MIN temp forecasts in the middle of the run that went -6, -4, -2 and most of the guesses were either close to -6 or -2, then the progression might run something like 20, 19, 18, 17, 17, 16, 16, 15, 15, 14, 14, 10, 6, 6, 5, 5, 4, 4, 3, 3 etc to reflect the forecast differences. I can't remember using this concept except in some minor applications like deciding where to double up the scores.

(4) No score(s) will be lower from minimum progression than the raw score achieved. This has been invoked in cases where there were no high scores but most forecasts were in the low end of the raw scoring range.

and just a note on why minimum progression is used at all, since it tends to maintain the same general scoring differentials within the month ... it equalizes monthly scores so that for our best 10 of 12 scoring format, we aren't all dropping the same two months.

Jpmarn

Models are showing a substantial chance that the 21.2°c barrier may not be breached by the end of the month. If it happens it would likely to be in the last few days of the month. My present guess would be the 28th at the moment. I am not trying to influence my entry as that was based on my guess then.