The 6am and 7am Warm Up

Danno

The last two mornings have thrown up an interesting characteristic where around 7am, the temperature rises up to +0.2c and then plumments to just 0.1c warmer than the lowest recorded temperature for the night in question.

For example...

On December 27th at 06.27am I record -2.4c. By 07.17am I record +0.2c and at 08.57am I record -2.3c.

On December 28th at 05.17am I record -1.3c. By 06.07am I record +0.2c and at 07.07am I record -1.2c.

Wierd.

Supercell

Is there any kind of a breeze just before or during the sudden swings in temperature?, if so might be mixing up the cooler and warmer air at ground and station hight.

Snowbie

Usually in certain conditions the coldest temperature of the night is around dawn when the heating of the upper atmosphere is warmed by the rising sun and the colder denser air at height sinks to the ground cooling things down more.

Also cold air moves from a cold to warm places, so if somewhere close to you is colder than you, the likely hood of the cold air replacing the warm air occurs.

If you live close to hills or higher ground, the air running down off them can also alter temperature.

Danno

about a 3mph west wind before both events... would 3mph mix it that much?

I noticed the same happened with Villian as well at 07.43am http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=ICARLOWC4&day=28&year=2008&month=12 also a west wind!

and here http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=ICARLOWC4&day=27&year=2008&month=12 at 07.28am from a NW wind...

The phantom W wind! Strikes at 7am

Villain

Yep I saw the same and was wondering was it odd or just I hadn't been watching before?