First air frost - 5 October

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First air frost - 5 October

Postby Stephen Burt » 2014 Oct 05, 09:38

A very large 24 h fall in temperature following yesterday's marked cold front -

Yesterday morning (Saturday 4 October), just after dawn the screen temperature was a little above 16°C. This morning saw our first air frost of the winter, the screen temperature just after dawn falling to -0.2°C - a remarkable 16 degC drop in 24 hours. The grass minimum was -4.9°C.

The average date of first frost over the 1981-2010 period is 22 October, so this is two weeks early; the first ground frost occurred on 21 August, the earliest on my local records back to 1972, the average date being about 17 September.

SB
-----
Stratfield Mortimer, Berkshire - central southern England
51.4°N, 1.0°W, 60 m AMSL, station grade A - AAAA47R
Records commenced here 1987 - local records available back to 1862
The Weather Observer's Handbook: www.measuringtheweather.com
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Location: Stratfield Mortimer, Berkshire; a well-exposed rural site, 10 km SW of Reading

Re: First air frost - 5 October

Postby Nick Gardner » 2014 Oct 05, 19:14

I was surprised by how cold last night was with a minimum of 3.1°C especially given my proximity to the sea which is currently a rather balmy 17.6°C. A northerly land breeze started very early at 20:45 and continued until well after sunrise. The wind then shifted quickly to a southerly at 11:00 and the temperature rose very quickly to reach a maximum of 17.2°C.

Normally a minimum temperature of 3.1°C would have given a slight grass frost but interestingly the grass minimum for last night was only 2.7°C.
Near Newton Poppleford, Sidmouth - Devon
50:41N 3:17 W; 20 metres AMSL; Station Grade B-BAAA37
http://www.ottervalley.co.uk
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Re: First air frost - 5 October

Postby greg_gruner » 2014 Oct 05, 20:27

The minimum here in Farnborough was 2.0C, with a frost visible on the ground and on car windscreens.
Greg Gruner
Farnborough, Hampshire
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Re: First air frost - 5 October

Postby Len Wood » 2014 Oct 06, 16:14

Minimum 6.5C here in Wembury.
This is not particularly low for this time of year.
For example
7th Oct 2012 min 5.7C
10th Oct 2013 min 6.0C
11th Oct 2013 min 5.0C

An air frost in October is a rare event here.
Only 2 since the record began in 1985:

17th Oct 1992 -0.6C
29th Oct 2008 -1.0C

Last winter my first and last air frost was -1.2C on 26th Nov!
Len

Wembury, SW Devon coast
N50.33 W4.13
Altitude 83 m asl
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Re: First air frost - 5 October

Postby Graham Easterling » 2014 Oct 07, 15:09

Last winter my first and last air frost was -1.2C on 26th November!


I recorded -0.4C on 23/11/13, then -0.8C on 26/11/13. Like you, no air frost since.
Today (7th October) the 1st sub 15C maximum (14.8C) since 14.5C on 26th May.
Graham

Penzance Weather Station
Grid Ref:
SW464231 - Post Code: TR18 4TP
19m AMSL - Aspect SSE
In a SE - NW orientated valley

23 Years of Penzance Weather Records : http://penzanceweather.atspace.com/weather.html
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Re: First air frost - 5 October

Postby Richard Hunt » 2014 Nov 05, 08:16

First ground frost of the autumn at this station (November 5th), with the grass thermometer reading a minimum of -1·5c.

Screen temperature increased overnight from 2·3c at 2350Z to 8·9c by 0600Z, wind has swung from southerly to north easterly. Feeling much milder than yesterday.

Tmin 2·3c.
COL Station: 25020.

Watson W-8681 AWS. Standard Stevenson Screen. Maximum and Minimum screen thermometers. Grass minimum thermometer.
5" Copper standard rain gauge. Roof mounted annemometer.
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Re: First air frost - 5 October

Postby greg_gruner » 2014 Nov 06, 09:54

Here at Farnborough I had my first air frost of the season this morning, min -0.2C. This is the first air frost since March 24th. This comes only 6 days after a max of 22.1C on October 31st! This dramatic change reminded me of when I lived in Canada as a child and autumn was a very brief season, with the temperature plunging dramatically.
Greg Gruner
Farnborough, Hampshire
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Re: First air frost - 5 October

Postby Richard Hunt » 2014 Nov 06, 22:16

Just shy of an air frost this morning (November 6th) with the screen minimum reading +0·2c.

Ground frost with -3·0c on the grass.

Air temp has risen this evening as the sky became overcast.

Currently the maximum for the day at 9·9c at 2215Z.
COL Station: 25020.

Watson W-8681 AWS. Standard Stevenson Screen. Maximum and Minimum screen thermometers. Grass minimum thermometer.
5" Copper standard rain gauge. Roof mounted annemometer.
Richard Hunt
 
Posts: 374
Joined: 2012 Jan 27, 19:23
Location: Hornsea, East Yorkshire. 10m AMSL


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