Strange temperature rise at Casement this morning?

Su Campu

Just noticed a huge temperature blip at Casement this morning. The temperature was steadily falling through the night and was at -3.9°C at 5am. At 6am there's a big jump in temperature and dewpoint to -0.7°C, then there's a big fall back down to -4.2°C.

I noticed that this rise coincided with a veering of the wind from westerly to northwesterly and back again after, and this would coincide with the location of a group of buildings that are only 25m away to the station's northwest.



Three things could explain this blip:

• It was just a false reading in both the temperature and dewpoint. Unlikely, as this would have been caught by Met Éireann in their QC before publishing to the web. (I don't know what was reported on the met.ie site, but the IWN site shows the blip - not sure if this uses raw synops or not)

• The rise was real and was as a result of the wind blowing warmth from the nearby buildings. Hmmm, with only 6-8kt winds and such cold conditions, it's unlikely that this would be possible, unless there was a nuclear reaction going on inside the building! (It is a military site afterall!)

• The government jet started up its engines on the apron just to the north of the station. This would be plausible, but maybe a more plausible one would be the garda helicopter either taking from or landing on the helipads on the same apron. I'm not sure where the anenometer is located, but if it's located elsewhere then it wouldn't pick up the heli's downwash.

Any ideas anyone? The station does seem a bit close to both the buildings and apron.

Rougies

The helicopter theory makes most sense to me.

I can't see an anemometer within the weather station area, no shadows long enough for 10m height (unless the pole is really skinny!). It might be on top of the control tower, or maybe on top of one of the tall lamposts?


(click below for high res image)


Actually, looking at the shadows from the control tower on the roof of the building to the right looks very like windvane/anenometer/antenna type stuff (or is that radar?).

Birdnuts

Could be a bit of cloud passing through which then cleared again:)

Danno

Similar effects from a NW breeze here, though *not* quite as dramatic... see the wee hours data from the 25th here Su Campu... http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=ICOLAOIS2&day=25&year=2010&month=11

Su Campu

That's a great photo rougies, did you take it from an airliner?

I'd say the shadow you speak of is probably from some communication antennae, but there is what looks like a red and white 10m anenometer between the two buildings at the top of the picture. A bad place to put one if it is it.

There was no change in cloud cover observed at the time so it couldn't be that. I reckon it was either an error, a heli or maybe the presence of the observer too close to the sensor!!

Rougies

Ah I see it, that's probably the anenometer alright. So it must have been either an error, a chopper, somebody standing next to it, or aliens! I'd still go with chopper.

As for the photo: http://www.bing.com/maps/ Choose "Bird's Eye" from the drop down menu at the top. Amazing coverage and quality, you can even look from N/S/E/W. Enjoy!