Holbeach No 2 WMO 03469 – A variable pitch?

52.87344 0.13854 Met Office Assessed CIMO Class 2 Installed 1/1/1985

A rather strange coastal site on The Wash it is better known as Holbeach Air Weapons Range. The Met Office was historically a branch of the Ministry of Defence (unsurprisingly so was the Ordnance Survey) and military locations still dominate Met Office sites. As a consequence public access to the vicinity of many weather sites is often heavily restricted or never allowed.

It is only in the modern internet age that scrutiny of such sites is partially possible through the likes of aerial imagery and the often promotional films produced from some sites. Recent site imagery of Holbeach calls its high CIMO rating into question.

Holbeach is only an occasional performer in the daily “Extremes” listing but appeared for the 25th November as a regional high. I do feel counting this coastal site as “East Midlands” is a bit odd.

Tim Channon reviewed the site and was unsure how it should be rated but at the time only had an aerial image to work from.

A noticeable point in his review was the short term spike of the temperature high point he referred to. This is noticeably similar to the graph for 25th November shown on WeatherObs where the reported maximum of 11.2°C was almost a degree higher than any hourly readings.

The subsequent advent of internet tools and more imagery now tends towards a different view. The site is quoted as at 3 metres amsl but just 8 metres away Elevation Finder indicates a height of 6 metres.

This warranted further imagery search to confirm the reason for this discrepancy and produced firstly from Google maps this.

The white square appearing just above the red and white striped pole is the screen which gives a useful scaling device as the base is 1.5 metres above ground level. The steps behind lead up to the coastal path indicating the screen sits at the bottom of a significant slope. Further confirmation of more height differentials comes from professional quality imagery courtesy of Jon Combe.

This image extract close up shows the screen on an artificially excavated shelf at the bottom of the upward slope to the east and a further downward slop to the west. Whilst this is not a “bad” site, the unnatural nature of the site and not representing the surrounding area makes it hard to justify its Class 2 status of 100% accuracy. At best this site is Class 3 or more reasonably considered Class 4.

I would welcome the views of any trained meteorological observers on the operational validity of this site.

via Tallbloke’s Talkshop

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November 27, 2024 at 04:04AM

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