Cold front Passages

Mothman

Following Yesterday's impressive cold front passage, that saw rapid temperature drops, hail, thunder, snow...I had a look back at previous significant similar events.
These are mainly based on graphs rather than memories, though I do remember some of them.
Perhaps the dates will help others to recount. Perhaps others I've missed?

Seems to be about one a year.

19/20th Jan 06
1st Jan 05 (memorable in Dublin)
28th Jan 04 (non event here but widespread thundersnow in Britain)
17th Jan 03
8th Mar 02
10th Feb 00
26th Nov 99

To recap on yesterday
Started at 1623, temp 9.9C, down to 5.7C by 1629, 4.4C by 1638 and 3.5C by 1700.

Heavy hail when temp was 9.9C has built up at bottom of westerly and southerly walls

4mm in just over ten minutes.

Wind has veered from S to W

No thunder , but otherwise the passage rates as a good one.

Mothman

Here are graphs for dates mentioned above. Pink line is wind direction, with S in centre.
8th Jan 2008

20th Jan 06

1st Jan 2005

28th Jan 04

17th Jan 03 anemometer at 2m height.

8th Mar 02 Previous weather station, 2 graphs. Rain figure is amount in 5 minutes


10th Feb 2000


26th Nov 1999



Now you can all breathe a sigh of relief that I didn't get a weather station sooner

Weather BOFH

Thanks for that MM, some interesting drops there, was yesterday's the largest you've recorded in such a short time?

Here's my graph of the drop here, it's my one and only like that as I only have my AWS 5 months now!

Snowbie

I tried to upload mine last night for the same peroid but site was oofline.Will post it here later.

Some cold front or squall line it turned out to be.The most infamous was the one that crossed the country overnight on July 25th 1985 that brought severe TS and large hail.
Unfortunately i had no rain gauge to record rainfall and no max/min thermo(just started out on my weather recording days around that time) to record low or high temps back then.A sultry night to begin but was quite cool the following morning and could have a more rapid drop in temp or extreme.Unknown really.

That one would have made yesterdays one quite tame,but at opposites seasons but different in nature, that yesterdays had other elements attached to it like snow.

Mothman

nemonoid wrote: »

Thanks for that MM, some interesting drops there, was yesterday's the largest you've recorded in such a short time?

It probably is. Convective showers in summer can easily have a 6C drop in a few minutes, but they generally bypass me and I can't find any that I've had with more than a 6C drop during 15 minutes.

Mothman

nemonoid wrote: »

Thanks for that MM, some interesting drops there, was yesterday's the largest you've recorded in such a short time?

I can now answer no, but I had to do some searching!

The first convective shower on 12th May 2003 saw a greater fall. No thunder in this shower, though a later one did rumble.
Temp fall
5min 3.6C
10 min 5.2C
15 min 5.8C
30 min 6.3C

This cold front passage
5min 2.6C
10 min 4.2C
15 min 5.1C
30 min 6.2C

I log at 5 minute intervals, hence the difference in fall compared to what I mentioned in OP, when I was actually clock watching. So the fall could have started 1 minute into a 5 minute interval, and so the actual fall could be
4min 2.6C
9 min 4.2C
14 min 5.1C etc,

Anyway the bottom line is that it does rate as one of the quickest temperature falls I've recorded.




Another issue I thought of is what is the speed of response of the thermometer to temp change. Its probable the falls are steeper, but the thermometer doesn't keep up.