Narrow warm sector - Saturday 3 January 2015

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Narrow warm sector - Saturday 3 January 2015

Postby Stephen Burt » 2015 Jan 03, 16:24

The south of Reading just caught the tip of a warm sector this afternoon. Today’s screen max (to now) was 10.3°C (at 1352 UTC), whereas the University of Reading site, just 10 km NE, reached only 6.3°C (at 1407).

The warm sector was 50 min duration, and included a NW’ly gust of 20 kn at 1358, when the wind at the university was NE just 1-2 kn. From 1320 to 1350 the temperature here rose 3 degC, and from 1350 to 1430 it fell 4.5 degC.

The timescale on the graph below is 0000-1600 UTC today, and the temperature scale is 1-11°C. The blue line is dry-bulb, the red line dew point, °C.
2015 01 03 1 min TT and Tdew plot - narrow warm sector (382 x 250).jpg
2015 01 03 1 min TT and Tdew plot - narrow warm sector (382 x 250).jpg (14.3 KiB) Viewed 488 times
Last edited by Stephen Burt on 2015 Jan 03, 16:26, edited 1 time in total.
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
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Stephen Burt
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Location: Stratfield Mortimer, Berkshire; a well-exposed rural site, 10 km SW of Reading

Re: Narrow warm sector - Saturday 3 January 2015

Postby greg_gruner » 2015 Jan 03, 18:14

The same here in Farnborough, Stephen (I noticed the big difference in max between my site and that of the university).

Here the temp rose from 6.0C at 1200 to 9.4C at 1400 (the max) then back down to 6.1C at 1500. So as one would expect, the max was a few minutes later here as the sector moved eastwards.

The lowest pressure here was 1014.4mb at 1300. The wind, which had been E, changed to NW at 1250, then SW from 1300 to 1400, before switching to NE at 1445 and staying there.
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Farnborough, Hampshire
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Re: Narrow warm sector - Saturday 3 January 2015

Postby Nick Gardner » 2015 Jan 03, 19:35

You didn't have to go too far south (and west) to receive a significantly bigger proportion of the warm sector today. The warmth started around 02:00 and lasted through the day and into the early evening. With a few sunny intervals this afternoon it helped to push the temperature up to a balmy 13.6°C.

Since 15:00 the temperature has dropped away but only slowly and even now at 19:30 with crystal clear starry/moonlit skies the temperature is still 6.6°C and the dew point holding up at 5.3°C, so nothing cold has arrived here yet.
jan3rd2015temp.jpg (37.37 KiB) Viewed 471 times
Near Newton Poppleford, Sidmouth - Devon
50:41N 3:17 W; 20 metres AMSL; Station Grade B-BAAA37
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Location: Rural riverside valley location near the village of Newton Poppleford and 2 km from the sea.

Re: Narrow warm sector - Saturday 3 January 2015

Postby Julian Mayes » 2015 Jan 09, 21:58

This 'inselberg' shape to the air temps was nicely shown by the network of road weather sensors in southern England that evening too. Not surprisingly, the period at the peak of the 'inselberg' became longer with increasing distance south of the M4 motorway - the differences within 50 miles north / south of the M4 in Somerset / Wilts / Gloucs etc were particularly impressive. As the 'redtop' newspapers would have it, south Somerset / Wilts / Hants was 'twice as warm' as Gloucs for a time!

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Home: West Molesey, Surrey Work: Central London
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