August 2024 C.E.T. and EWP forecast contests

[Summer Sun]

17.9 to the 8th

2.1c above the 61 to 90 average

0.9c above the 81 to 10 average

[Roger J Smith]

17.9 to the 8th

2.1c above the 61 to 90 average*

0.9c above the 81 to 10 average

0.5c above the 91 to 20 average

(as 61 to 90 is end of Aug and not current running average, it would likely be around 1.4 for a direct 1st-8th average only)

===============

The EWP was 9.2 to 7 Aug and looks to be around 14-15 now. GFS says about 30 additional by 25 Aug. (for 45 total)

Also GFS indicates CET will be around 17.2 C by 25 Aug -- a high point near 19 C is probable for the report on Tues for 1-12 Aug, record for 1-12 average is 21.0 (1975) and it was 20.8 in 2003, 20.1 in 1995, 19.8 in 2020, 19.6 in 1997 and 2021, and 19.5 in 1911 and 1990 (all 1-12 averages, 1911 increased to 19.7 after 13 Aug). 2022 was 19.0 and peaked on 15 Aug at 19.7 C. 

[WYorksWeather]

 Roger J Smith Scatter is still huge in the second half - I think much will depend on whether we tap into any further warmth in the second half, as GFS 00z and 06z were playing around with earlier today, but those were warm outliers. The 12z was slightly on the cool side of the ensemble, but not an outlier.

Anything from a record-challenging month (if we get another significant warm spell in the second half) to something near average is plausible I think. On current evidence my 18.5C is a little on the high side but still doable - personally I think forecasts in the 17s are best placed at the moment. Of course if one of the outlier runs does come off then all bets are off, as we have seen with forecasts showing how easily temperatures can lift in to the 30s by day.

[snowray]

 WYorksWeather Coincidentally my calculations also came up with 17.2c as a final figure but this was without any further heat spikes, or any more prolonged mild spell later in August. I certainly would agree that things could end up higher in the 17's and we are seeing more warmth than what the models were showing us, particularly for more southern areas. Of course this is just a ballpark figure at this stage and we might end up seeing early Autumnal conditions by the last week of the month.

Edited August 9, 2024 by snowray

[WYorksWeather]

 snowray It's always interesting how much difference a few warmer or cooler days can make, even if not reflective of the whole month. February 2024 was cost a record because of only a few cooler days right at the end - otherwise it would have comfortably broken the old CET record from 1779.

Same could be true this month, in either direction. A late heatwave could easily add a degree to the monthly CET, whereas an unseasonal cold northerly could subtract one.

It makes sense though - you divide the difference in temperature by 30 to get the influence on the monthly CET, so six days of weather at 5C above average have as much effect as 30 days at 1C above average.

[snowray]

 WYorksWeather And of course there can be such a difference between the SE and NW temps, Stonyhurst generally speaking cooler, but not always. Any Scandi highs/easterlies and the opposite sometimes happens particularly in late Spring/early Summer. 

Down here it matters not if it's an easterly or westerly wind, it's almost always windy out with suppressed temps as compared to just a mile or so inland.

[Derecho]

 

Based on yesterdays EC 12z control we've got a pretty average picture once this plume passes. A few warm nights scattered about keep the CET up on a few days. I think we'll end up on a CET of around 18C by the 20th. 

After that the EC control was amongst the coolest ensemble members but a subtle reminder the nights are getting longer.

In the near timeframe, the adjusted EC output in my table above is going for a CET of 23.0C on Monday, not bad!

[The PIT]

Sunny Sheffield still at 17.5C +0.8C above average. Rainfall 9.6mm 14% of the monthly average.

[Frigid]

 Derecho An inverse of June/July perhaps? First half warm, then a much cooler second half. My prediction could come in close. 

[Summer Sun]

18.1 to the 9th

2.3c above the 61 to 90 average

1.1c above the 81 to 10 average

[Summerlover2006]

I think we might just finish in the 18s wish i could change my guess now.

[WYorksWeather]

 Summerlover2006 Still a lot of model uncertainty for the second half so I think your guess at 17.4C still has at least as good a chance as mine at 18.5C, if not a better chance.

It should be remembered that August, like September and October, is a very rapidly cooling month. Hot days with means above 20C become significantly harder to achieve in the second half, though of course not impossible. That means that it becomes very hard to add much to the CET in the second half after a very warm start, as the ceiling for temperatures is quite a lot lower. Even if we were at 18.5C after the first half it'd still be quite tough to stay in the 18s in the absence of another substantial heat spike.

[The PIT]

Sunny Sheffield up to 17.6C +0.9C above average. Rainfall up to 10.4mm 15.1% of the monthly average.

[Metwatch]

A dry opening 10 days of the month, and doesn't look to increase much until strong fronts start to arrive and head further south later next week. Thunderstorms might increase the total a little tomorrow though. As much as I do appreciate less rain, it's looking increasingly unlikely this August will be able to reach my guess of 76mm. A drier than average August looks favoured at the moment.

CET going up with this heat spike, then afterwards cooling down. Tricky to say how cool the second half of the month could be, but with near constant westerlies i'd imagine that would help to drop the CET down into the 17s soon enough. I reckon August will be warmer than the 1991-20 average of 16.6C, but unlikely to end up more than 1C above it.

Edited August 11, 2024 by Metwatch

[Summer Sun]

18.1 to the 10th

2.3c above the 61 to 90 average

1.1c above the 81 to 10 average

[damianslaw]

A very warm first half. Easily in the mid 18s at half way stage with 3 very warm CETs on the way.

August is though a cooling month, by month's end notably cool nights can occur under clear skies without a continental or tropical maritime airflow.

An above average 61-90 mean though looks a dead cert. 

[Roger J Smith]

In before anyone asks, top first half of Aug CET values (to 15 and 16 Aug although 2024 could peak before that). 

List includes all years with any running average of 18.0 or above after 15th. All but one in list produced a value on one of the checkpoint dates (1944 on 19 Aug peaked at 18.0, other "near miss" situations are listed below table.

2024 added to table, will be updated to end.

YEAR __________ 1-15 CET_1-16 CET __ 1-20 __ 1-25 __ end of AUG CET (v2.1.0)

1975 ___________ 20.7 ___ 20.4 _______ 19.8 ___ 18.8 ___ 18.7

2003 ___________ 20.1 ___ 19.9 _______ 19.3 ___ 19.2 ___ 18.3

1995 ___________ 19.7 ___ 19.8 _______ 20.1 ___ 20.0 ___ 19.2

2022 ___________ 19.7 ___ 19.6 _______ 19.3 ___ 19.1 ___ 18.7

1997 ___________ 19.6 ___ 19.6 _______ 20.0 ___ 19.7 ___ 19.0

2020 ___________ 19.6 ___ 19.5 _______ 19.2 ___ 18.7 ___ 17.7

1911 ___________ 19.6 ___ 19.4 _______ 19.2 ___ 18.7 ___ 18.2

2004 ___________ 19.4 ___ 19.3 _______ 18.9 ___ 18.2 ___ 17.6

1856 ___________ 19.1 ___ 18.9 _______ 18.0 ___ 17.2 ___ 16.9

1773 ___________ 19.1 ___ 18.8 _______ 17.9 ___ 17.4 ___ 17.2

1933 ___________ 18.7 ___ 18.5 _______ 18.0 ___ 17.4 ___ 17.6

1990 ___________ 18.7 ___ 18.4 _______ 17.8 ___ 18.0 ___ 18.0

1868 ___________ 18.6 ___ 18.5 _______ 17.9 ___ 17.2 ___ 16.8

1792 ___________ 18.6 ___ 18.5 _______ 17.8 ___ 17.3 ___ 16.9

1800 ___________ 18.3 ___ 18.3 _______ 18.6 ___ 17.4 ___ 16.8

1884 ___________ 18.3 ___ 18.2 _______ 18.1 ___ 18.1 ___ 17.2

1938 ___________ 18.3 ___ 18.1 _______ 17.6 ___ 17.0 ___ 16.3

2024 ___________ 18.2 ___ 18.0 ________ 17.6 ___ 17.1 ___ 17.0

1937 ___________ 18.2 ___ 17.9 _______ 17.4 ___ 17.2 ___ 16.9

1893 ___________ 18.1 ___ 18.3 _______ 18.7 ___ 18.2 ___ 17.4

1871 ___________ 18.0 ___ 18.1 _______ 17.9 ___ 17.6 ___ 17.2

1899 ___________ 17.9 ___ 17.9 _______ 17.9 ___ 18.1 ___ 17.8

1944*___________17.8 ___ 17.8 __18.0_ 17.8 ___ 17.4 ___ 17.0

(below this level, years are not all listed for first 2 col, these years qualified on 20 or 25 Aug)

1876 ___________ 17.7 ___ 17.9 _______ 18.0 ___ 17.1 ___ 16.5

1947 ___________ 17.5 ___ 18.0 _______ 18.7 ___ 18.7 ___ 18.6

1955 ___________ 16.8 ___ 17.0 _______ 17.4 ___ 18.1 ___ 18.1

================================= [] ===============================

near miss and unknown daily situations (after 15 Aug)

* 1944 in table was only at 18.0 on 19 Aug. A few years in table had slightly higher peaks than any checkpoint, but differentials of 0.1 or 0.2 at most. 

peaked at 17.9 _ 2018 (15,21,22), 1842 (18), 1969 (15,16), 1932 (20), 1781 (15), 1976 (25,26,27)

peaked at 17.8 after 17 Aug _ 1959,1983 (26)

peaked at 17.7 after 17 Aug _ 1780 (21), 1819 (17,18,24,25,26), 1984 (31)

peaked at 17.6 near end __ 1779 (31), 1826 (30,31)

unknown daily info, 17.6+ __ 18.3 1747, 17.8 1736, 

Edited August 31, 2024 by Roger J Smith

[The PIT]

Sunny Sheffield up to 17.7C +1.0C above normal. Rainfall 10.5mm 15.3% of the monthly average.

[Summer Sun]

18.2 to the 11th

2.4c above the 61 to 90 average

1.3c above the 81 to 10 average

[reef]

If the GFS 12z came to fruition, here we'd be at 19.2C to the 28th. My warmest August back to 1980 is 18.5C in 1990. 2022 was 18.1C

I wonder if we're going to have an unexpectedly very warm month?

[Methuselah]

 reef

Which would suit me fine. My idiotic guess was 19.1! 

[WYorksWeather]

 reef Hm - not sure about unexpectedly. I think a lot of people have just stopped following it after a fairly non-descript June and July. But even though other than today there hasn't been any massively stand-out warmth in this first half of August, the key has been the absence of any cool period.

The fact that any particularly cool north-westerly or northerly period keeps getting pushed back and downgraded is starting to lead me to believe that maybe it won't happen this month, in which case a very warm outcome is likely even without any spectacular warmth.

Of course if we do get another plume (or two) or a more sustained spell of moderate heat, then all bets are off. Anything from a little above average to record breaking is realistically possible, I think.

[Don]

1 hour ago, reef said:

I wonder if we're going to have an unexpectedly very warm month?

Hmm, not sure if there's any such thing as an 'unexpectedly very warm month' these days if you get my drift?! 

[Dancerwithwings]

 Don

Mother Naughty Nautilus….writes them words “ unexpectedly “ 

It not….how boring the expected would be Don …it ani’t for us

[Don]

1 hour ago, WYorksWeather said:

Of course if we do get another plume (or two) or a more sustained spell of moderate heat, then all bets are off. Anything from a little above average to record breaking is realistically possible, I think.

Could we see a 'back to front' version of last summer (temperature wise), i.e. 2023 had a record breaking hot June, followed by a mediocre July and August and 2024 a mediocre June and July, followed by a record breaking hot August?!  An outside chance this August will be the hottest on record, but like you say, possible at this stage!