HereFord:Credenhill Addendum – An open request to the Met Office to justify their readings.

The above is the regular daily publication from the Met Office of a range of weather “extremes” noted the previous day. This is a highly publicised feature of Met Office output as it also appears in precis form on the “X” feed. Dr Eric Huxter has researched this data in great detail as presented in this detailed podcast. Eric has obtained the exact timing of the above peak reading as 14:11 GMT.

Outwardly there is nothing particularly unusual about the above reading – it is well within the normal range of daily highs for the latter part of October in England. There should be no need whatsoever to even query the accuracy of the above reading to the general public…….unless you look a bit deeper, which I shall in this report and ask the Met Office to defend this reading.

I originally reviewed Hereford here. The main points to note are that this was formerly RAF Credenhill/Hereford and is currently Stirling Lines and home to the Special Air Service – SAS. The weather station has been a full synoptic reporting unit since 1999. It lies under 200 metres to the southwest of the Helicopter Landing pads/runway and has hedging to the west and south shielding the screen from winds to those directions – this image from 2022 indicates the likely levels of shading.

It is worth contrasting the above to the site conditions in 1999 when installed as below. Note the much smaller apron area . the lack of the helipad/runway system and much less boundary hedging.

The above is just background information but may prove to be highly relevent later on. For now back to that 26th October reading at 14:11 of 19°C. This is the weatherobs graph detailing the temperature, wind speed and direction at 10 minute intervals.

Viewed like this there is a very noticeable “Spike” in temperatures – a point Dr Huxter makes very emphatically in his presentation. The hourly reading at 14:00 is reading 16.9°C but just 11 minutes later it has risen to 19.0°C – an increment of 2.1°C in just 11 minutes. This is unusual but not particularly so until one considers just how frequently this “spikey” phenomenon occurs at Credenhill. Dr Huxter provided me with this data demonstrating the probability of these rapid temperature spikes occuring at a CIMO Class 1 benchmark site (Rothamsted). Clearly the chances are frequently very remote and reflect problems with the likely inaccuracy of area representative readings at Credenhill demonstrated in its lowly Class 4 rating.

BUT it certainly does not stop at this. If this sudden temperature spike were a purely natural area wide event it would also be reflected in other weather stations readings regardles of being them controlled by the Met Office or being Private Weather Stations (PWS). Fortunately, just 685 metres away in Dovecote Lane, Credenhill there is a PWS coded IHEREF49 and reporting to Weather Underground’s highly commendable website. https://www.wunderground.com/dashboard/pws/IHEREF49/graph/2026-10-26/2026-10-26/daily

So what does the data from this site look like for the same period?

See any “spikes”? No me Neither. So firstly let’s put hourly readings side by side.

Time………………………..Met Office Hereford Credenhill …………………IHEREF49……………..Difference 1HEREF49 over MO

09:00 ………………………………………10.4°C……………………………………….10.6°C…………………….-0.2°C

10.00……………………………………….11.2……………………………………………11.2…………………………Level

11.00……………………………………….12.4……………………………………………11.9…………………………-0.5

12.00……………………………………….14.1…………………………………………..14.1………………………….Level

13:00………………………………………16.2……………………………………………15.7………………………….-0.5

14:00………………………………………16.9…………………………………………….16.7………………………….-0.2

Up to this point there really is not much difference with the two sites in close step as two such near neighbours would naturally be expected to be………..but then at closer time resolution

14:10………………………………………18.9……………………………………………17.4……………………………– 1.5

14:11……………………………………….19.05 (rounded down unusually)…not known……………………n/a

14:20………………………………………18.5…………………………………………..17.6…………………………….-0.9

14:30………………………………………18.3…………………………………………..17.7…………………………….-0.6

14:40……………………………………..17.7…………………………………………….17.6…………………………..-0.1

15:00……………………………………..17.5…………………………………………….17.6…………………………..+0.1

This dramatic divergence was short lived – going back to hourly readings:

16:00…………………………………….17.0……………………………………………17.2……………………………..+0.2

17:00…………………………………….16.2……………………………………………16.8……………………………..+0.4

Note the PWS peaked at only 17.7°C equating to 1.3°C lower than the Met Office reading.

There are two possible inferences here – a wider area spike in temperatures did occur but only the Met Office site picked it up and possibly inferior equipment at the PWS resulted in it being missed there despite being just a few minutes walk away. Or alternatively the spike in temperatures was an extremely local event solely occuring within the Stirling Lines site itself.

So firstly I shall disprove that this was any sort of wider area event by checking all the other PWS in the area. Firstly IHEREF127 2.25 Km distant alongside Burgh Hill Golf Course in open countryside. No sudden temperature rise and peaked at just 17.4°C. At all other times of day readings tracked in close comparison to the Met Office site but not at all during that 14:00 to about 14:40 spike.

Moving away from Weather Underground and onto the Met Office’s own WOW site there are several nearby recording points shown here.

Did any of these sites show a sudden spike in temperatures? Not one of them did, furthermore the peak temperatures recorded were nothing like that maximum the Met Office is claiming for their own site. The public can check these all out at any time as this site allows revesion back to earlier dates. Nowhere recorded a maximum above 17.4°C NOTE It is also possible on this WOW site to go to individual locations “data tables” for fine time scale resolution – this is an example below of that “spike” period for the Park Street in Hereford site – no spikes shown.

I am very confident indeed that there was neither a general nor wider area sudden temperature spike in the Credenhill area yesterday and I am equally confident that the temperature recorded there of 19°C was from an unnatural source. So what could that be?

Going back to the weatherobs data image , it shows the wind during this peak period was veering from from the SSW through SW to WSW and running from 7 through up to 11 and then down to 10 kph  i.e. ranging from 1.9 to 3 metres per second at 10 metres height. This is below the required Stevenson Screen ventilation levels specified for accurate readirngs (Aitken Effect) as behind the hedge at 1.25 metres height and inside the screen it will be almost static air.

As stated the screen sits about 200 metres to the south west of the main Helipads/runway. Helicopters (like conventional aricraft) prefer to take off into the wind and it is also the standard operating practise to not take off or land approach over the developed area to the north of the site (if this can be avoided) for safety purposes. Experienced aviators have advised me that helicopters would raise to a hover, orient take off direction and increase power before moving away. For operational fuel economy ascent rates are not steep in open clear sites and they would likely be in the region of 35 metres above the screen passing overhead into the wind for a routine flight. Rotor wash would still be significant and engine exhaust still detectable at the surface. Helicopter aerodynamics often result in pockets of warmed air being tranported with them on ascents (“entrainments”) for a while beofre falling away.

In the likely event of helicopters taking over the screen in such conditions, artificially warmed air may well be “rammed” into the screen rapidly replacing the natural ambient air with the surrounding hedges holding in further warmed air around it. A rapid increase within the screen would be reflected in sudden temperature rise which would only slowly dissipate over time given this screens natural wind sheltered spot.

This suggestion is a hypothesis of mine (plus that of experienced aviators) and of course could very readily be disproved by the Met Office themselves by providing evidence to demonstrate there were no aircraft movements yesterday around the time of this and previous events. This is particularly important given the regularity of noted national daily highs from this site and the large scale of the variance from near neighbours.

I hope the Met office responds to explain this potential problem as if this suggested cause is correct , then it is a significant problem both here and elswhere . There are a surprisingly large number of weather stations in extremely close proximity to Helipads and this issue certainly needs addressing.

Source: https://talkshop.blog/2026/10/27/herefordcredenhill-addendum-an-open-request-to-the-met-office-to-justify-their-readings/