December 2015 - 'Warm & Dry'

[Nicholas Gardner]

This December seems to be re-writing my 10 years of recording for temperature.

1st - 12th
Mean minimum = 9.3°C
Mean minimum = 13.3°C
Mean maximum = 11.3°C
Rain = 19.4 mm
Sunshine = 24.3 hours.

The minimum high of 13.1°C on the 3rd was higher than anything else I've recorded for December.

The mean temperature is currently running slightly higher than the overall mean for November (11.2°C).

It has also been rather dry with all months this autumn and winter so far being drier than normal.

As following on from November, it is turning out to be a dull month. December 2014 had (1st - 12th) 48.4 hours of sunshine and a monthly total of 103.5 hours. I doubt that this month will see anything like those figures.

[Paul Swinhoe]

Congratulations Nicholas!
You are the first person to post to the new forum. Many thanks for that - I now know it is working properly!

[Edward Graham]

Just checking that I can post too Paul... (so if you see this - success too!).

But what a shame that we have missed the past month or so of weather on the forum!- (a new UK 24-hr rainfall total of 341mm, thunder, lightning & snow here too, etc..)

Nicolas, here in Stornoway at the far opposite end of Britain - it's been a very wet first ten days of December, we've reached the average monthly total already(130mm), the sunshine total is only a paltry 7.5hrs, but air temperatures are close on the monthly average. In the 33 days to 11 Dec, we've had 280mm of rain, an exceptional amount (exceeded only by Dec 2013 in recent met memory).

And today (Sun 13th Dec)- freezing rain/ glazed ice (again!) - see photo attached:

2015-12-13 11.21.00_s.jpg (63.88 KiB) Viewed 30780 times

sincerely
Eddie Graham, Stornoway, @eddy_weather

[Roger Brugge]

What happened to winter? - the daffodils are out in parts of Maidenhead now.

Roger

[Paul Swinhoe]

You are obviously too far south Roger!

I just spoke to my sister, who lives in Weardale, County Durham - they have had snow for the last three days, and Storm Desmond caused havoc in the North Pennine Dales as well as the Lake District. The river Wear rose and washed away a bridge in Stanhope, and many houses had serious damage to their rooves during the gales, which also blew over large trees, damaged fencing, etc. A friend of hers was caught in the car crossing a ford at Rookhope and had to abandon her car. It was found a day later, several miles downstream at Eastgate.

[Martin Rowley]

... definitely a divided nation at the moment, as regards weather at least! Locally (East Dorset), the anomaly on LTA (1981-2010) with respect to temperature is +7.1C for minimum and +4.6C for maximum. Rainfall hasn't been anything too problematic - average or below for the last three months - but the sunshine absence has been noteworthy: ~40% of LTA for November (October also below average), and this month (so far) running at circa 60% of the daily average (to yesterday's Hurn data) and today won't add much if any. Long term forecasts (10+ days) I've seen suggest no major change - some sort of "attempt" to approach the average temperature curve but overall staying above average with rainfall hit and miss.

Although not approaching the 'record-breaking' warmth of last year (warmest in Hurn record which begins 1957), provisionally we're going to end up with 2015 being in the 'top-10' of warmest years in this neck of the woods.

Frankly, a bit boring! No doubt the good folk of Cumbria would welcome that.

Martin.

[Graham Easterling]

Certainly a remarkable December in Penzance. Currently the mean temperature is running at 11.9C, that's 2.6C above my previous warmest December, 1994. Fronts have been fairly weak up until now, this morning's being the most active so far.

Due to the cool summer the mean temperature for the year so far is 11.8C, bang on the mean annual temperature over the last 25 years. I think we were badly hit by the Atlantic cool pool in Summer.

The top 3 warmest years being:-
2007 - 12.6C
2003 - 12.4C
2006 - 12.3C

[Nicholas Gardner]

Last night recorded a minimum of 13.2°C just beating the previous minimum high of 13.1°C recorded on the 3rd.

This month's mean temperature (1st - 16th) is currently running at a very high 11.5°C.

Graham, yes this year's mean temperature is way down on last year due to a run of cool weather, especially for the 2nd half of the summer. Here, the annual mean temperature is now at 11.7°C. Last year's mean temperature was 12.3°C up to the 16th of December and the year ended up at 12.2°C.

[Martin Rowley]

... half-way through the month: 24hr mean temperature here = 11.3degC, which is +5.8C on the eLTA 1981-2010.

No long-term records for my site to set this against: we only started here in 2007, but at nearby Hurn (circa 3.5 mi / 5.5 km to the SE of us), the latest mean (using SYNOP data) = 11.2, which represents +5.9C on their all-series [1957-2014] mean.

By this measure, for this part of the world these values would drive a 'coach and horses' through previous records (if maintained) as the previous warmest December in the Hurn record was that of 1974 with 8.5degC. It won't stay as warm as this - the extended ensemble output (and synoptic pattern diagnostics driving them) indicate a change to a 'westerly/Atlantic' type in a few days time . . . BUT, it's noticeable that the EC output - the model with the highest reliability factor of all global models, suggests that although we lose the S/SSW flow, future patterns still have a 'south of west' bias to them - so whatever, I suspect that we're on course for a notable 'record-breaking' December 2015. GFS ENS also show a sharply positive 850hPa T profile from Christmas Day onwards.

Martin.

[Nicholas Gardner]

... half-way through the month: 24hr mean temperature here = 11.3degC, which is +5.8C on the eLTA 1981-2010

The remarkable warmth of this December continues and there were over 5 hours of sunshine today, which came as a shock to the system! A 'pulse' of warm air moved through last night around midnight briefly raising the temperature a couple of degrees to 15.3°C 23:50.

Up to the 20th:
Mean minimum = 9.8°C
Mean maximum = 13.5°C
Mean = 11.7°C.
Rain = 45 mm
Sunshine = 32.4 hours

This December will probably end up warmer than November, January, February, March & even April of this year.