Llanbedr, with attempted record weather analysis

Posted: October 6, 2012 by tchannon in Analysis, Surfacestation


Llanbedr met site is of special interest.

  • defunct
  • exposed ground pattern
  • holds warmest ‘night’ record for May in Wales
  • is an unusually well exposed site
  • near coastal
  • has distinct hardstanding very close
  • some meteorological information is available from May 2002
  • RAF/RAE Llanbedr has associated historical interest as part of the British guided missile development program

Llanbedr (RAF Llanbedr, links in main article)

Holds record warmest May “night” temperature for Wales
May 18.6 °C 17 May 2002 Llanbedr (Gwynedd)

Altitude 6 metres

Estimated Class 4, fails Class 3 on >10% hardstanding within 10 metres.

UHI, strong local site (also see article here), distance none.


Aerial image from 2006 just after the Met Office meteorological site closed and has an optically bright site paving pattern after the instruments were removed. The runway was used by unmanned target drones. Marked with X to signal disused.

The photo also nicely demonstrates how difficult it is to purely locate met sites from the air. (mauve dot)

A 2009 image shows how the met base pattern is now dull and of course is derelict.

Between the runway and the sea are dunes of considerable height, more than enough to break the prevailing south west wind or sea breeze. Takeoff and landing a remote controlled drone in a turbulent cross wind must have been educational.

A photograph showing the runway and dunes, together with some history is on the excellent Control Towers web site.

Weather May 2002

There is no public data from the Llanbedr met station so the only option is try and figure it out from what is available.

Archive of zero hour synopic charts
“Archiv der 00 UTC UKMO-Bracknell-Bodenanalysen (ab 27.01.1998)”

Here are the three charts.


16th May 2002


17th May 2002, day of record


18th May 2002, day after.

It was a very complex situation, confused conditions with an occluded front forming.

Prior to this, 56km NNW, RAF Valley METAR shows a long period of an unusually steady due South wind, things then go unstable with I think an electrical storm in the early hours of the morning of the record, preceding the weather front, which itself produces little rain, drizzle, the usual can’t-make-it’s-mind-up of occluded. Wind is erratic.

Weather Underground use METAR. Station ident EGOV and carry an archive. http://www.wunderground.com/weather-forecast/UK/Valley.html

Valley is a manned station so there are proper human comments. Unfortunately METAR is unreliable, with missing data rather frequent as we shall see.

There is also CLIMAT information for Valley which proves illuminating:
2002 05 17.9 17 8.0 04 22.9 16 2.5 04 19.2 17 88.9 24

Highest mean temperature for the month 17.9C on the 17th May

Highest maximum temperature 22.9C on the 16th May, the day before Llanbedr broke it’s record, suggesting prior temperature had primed the site for a warm night.



That is the best I can do at the moment. More and better data is needed. Labels are the Valley reported conditions.

A question this does not answer is whether rain fell on the Llanbedr asphalt and concrete bringing up ground warmth. The previous day was part sunny before clouding over.

Llanbedr flying

Drones were mainly the Anglo-Austrailian developed Jindivik, photo of one at Llanbedr leaving it’s trolley on takeoff http://www.airsceneuk.org.uk/hangar/1999/dera/targets.htm
(more links in the appendix)


Map top to bottom yellow markers, RAF Valley, Llanbedr, Aberporth, the latter was the launch site for Bloodhound MK2 surface to air missiles.

Bloodhound MK2 was a cold war era radar guided twin ramjet mach 2.7 missile, using rocket assist takeoff, going supersonic inside the length of a met station enclosure. Warhead was an exploding steel chain, the idea being to miss the target, cut the target in half on the way past. Maximum range according to various sources anything from 70km to 185km, take your pick.
Last service was I think with the Swiss air force 1999

A web search will produce a great deal of material on the drones and missile development including launch videos, all declassified now.


And the wonderful PPRuNe forum site, here is a thread asking for stories
Not sure if this is the right place to post but I’m interested in hearing from anybody who worked with ‘Jindy’ in the U.K, Woomera, or Jervis Bay. My father, an ex RAF pilot, was a ‘batsman’? at Woomera then Jervis Bay NSW. Any stories much appreciated.”

  1. TonyN says:

    I think you are right to be suspicious of that record. Our house overlooks the airfield and we don’t really do seriously warm nights around here, not compared to what might be expected in an urban area. What is the reference period?

    I also seem to remember that there was a weather station near the hangers at one time.