Tag Archives: East London weather statistics

March 2019: mild and wet

March was mild, particularly compared with last year. And wet though, like February, the rain fell at the start of the month, leaving a dry end.

The mean temperature finished 9.4C that’s 1.7C above average and over 3C warmer than last March.

Some 54.5mm of precipitation was recorded,  134 per cent of the 1981-2010 average.

Some  109 hours of sunshine were recorded, that’s  precisely average.

Just one air frost was recorded.

To view full stats follow this link:http://1drv.ms/1kiTuzv

march 2019
‘Feels like’ maxima.
march 2019 feels like
key
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Is it warm, cold or just normal?

Saying how warm or cold a day feels is subjective; one person’s hot day in spring is another’s ‘on the warm side’. Similarly when someone says the temperature on any given day is ‘normal for the time of year’ others will be exclaiming how cold they’re feeling.

The ‘heatwave’ in February was a case in point. Though many places recorded their warmest February maxima on record many were saying it was just a nice, warmer than normal spell of weather.

Some years ago the Met Office issued guidance on how warm or cold a day was relative to the anomaly. Earlier this month the table was posted on Twitter and I have plotted a graph for the spring period.

Today’s (March 22nd) maximum of 11.1C is therefore described as ‘normal’.

temp feel

cold hot warm

 

Data reveal windiest March for 4 years

March 2019 has been a windy month so far. With 11 days to go it is already the windiest March for 4 years and the windiest month for over a year.

The windiest month recorded since 2013 was December 2015.

Looking at the data in general there seems to be a pattern of a windy month that is followed by a decline of between 10 and 13 months.

monthly wind run

 

Spring or still winter? Plants reveal all.

With the record warm spell last month and high sunshine totals you would think that the growing season is well under way. Spring bulbs have been out for weeks, trees are blossoming and many shrubs are on the verge of flushing.

But a look at the local temperature records over the last six years shows that things aren’t as advanced as previous seasons.

Considering the period from December 1st – in recent years a date when it is common to see bulb shoots beginning to emerge – to March 10th reveals the following table in terms of growing degree days.

growing degree days

The warm days of last month were cancelled out by cold, frosty nights, leading to little net warmth. And the last ‘growing degree-day’ was on March 2nd. Nevertheless growth is further on than last year that saw record cold in March. 

The season is a long way behind 2015-16, however, which saw a record-breaking mild December.

Looking at the list below, and the at best average outlook, we’ve still got a way to go before we’ll see most trees in full leaf…

plant development
This list courtesy of Wikipedia

 

 

February’s record diurnal temperature ranges

Last week’s warm spell not only saw national maxima records tumble but, locally, saw the February diurnal temperature range record shattered too.

Four days of near cloudless skies produced classic conditions whereby the maximum amount of solar heating by day was followed by clear nights allowing all that heat to escape with air frosts forming.

The spell saw five new entries in the ‘top 10’ of February diurnal temperatures since 1959, with both the 25th and 26th surpassing the record set in 1976 by at least 0.3C.

feb diurnal new
Top 10 February diurnal temp ranges

The diurnal ranges were not enough to make the annual list, however

top 10 diunrals
Top 10 diurnal temperature ranges since 1959

 

 

Winter 2018/19: average with extremes

The winter of 2018/19 will probably be remembered most for the remarkable warmth in the last week of February. And for its lack of snowfall.

The mean temperature finished 6.1C, that’s 0.7C above average, the mildest for 3 years.

Rainfall was below average: 127mm fell, that’s 87 per cent of average and the driest for two years.

Sunshine was well above average: 211.6 hrs is 126 per cent over average, the sunniest for seven years.

The warmest day of the winter occurred on December 30th with 14.2C recorded. The warmest night was on January 28th when the temperature fell to just 10.8C.
The wettest day of the winter occurred on January 2nd when 15.3mm was recorded.

Snow first fell on 5 days between January 22 and February 1st: five days of snow falling and two days of snow lying over the three months is below average.

There were 29 air frosts during the three months, seven above the 1981-2010 average.

A full weather diary is available for the months of DecemberJanuary and February. To view full stats for each month follow this link:http://1drv.ms/1kiTuzv

TMax winter

Summary for period 01/12/2018 to 28/02/2019

Temperature (°C):
Mean (min+max)   6.1
Mean Minimum     2.6
Mean Maximum     9.7
Minimum          -6.5 on 30/01/2019
Maximum          18.7 on 26/02/2019
Highest Minimum  11.5 on 06/12/2018
Lowest Maximum   1.3 on 23/01/2019
Air frosts       29
Rainfall (mm):
Total for period 127.0
Wettest day      11.4 on 20/12/2018
High rain rate   28.1 day 26/01/2019
Rain days        31
Dry days         59
Wind (mph):
Highest Gust     31.1 on 09/02/2019
Average Speed    2.8
Wind Run         6152.3 miles
Gale days        0
Pressure (mb):
Maximum          1043.8 on 02/01/2019
Minimum          980.4 on 01/12/2018
Days with snow falling         5
Days with snow lying at 0900   2
Total hours of sunshine        0.0

Longest winter ‘heatwave’ since 1959

With the return of more seasonal temperatures February 2019’s heatwave already seems like a distant memory.

Looking back at the stats for this area the past eight days have seen an average anomaly of 7.7C, beating the previous eight-day long warm spell of December 2015, which returned a mean anomaly of 7C. That spell was quickly followed six-day long warm spell that had a mean anomaly of 6.6C. There appears no chance of the heat returning any time soon.top 5 winter heatwaves

Wanstead missed out on breaking the February high temperature record. While Kew Gardens recorded a high of 21.2C, the local area reached just 18.7C, falling short of the record of 19.7C set in 1998.

St James’s Park, our closest official climate station, set a new top 3 of TMax values. , as did Heathrow.

 

Diurnal temps present a clothing challenge

The erratic onset of spring in some years often presents that problem of what to wear every morning. During the current warm spell I’ve seen all manner of attire on the school run; everything from T-shirt and shorts to full winter regalia topped off with hat and gloves.

The position of the sun is now bringing in to range the season when the gap in temperature between day and night can be at its greatest.

On Saturday (23/2), virtually unbroken sunshine and ‘thick’ air saw the temperature in Wanstead peak at 16.1C before clear conditions overnight saw the minimum plunge to just 0.2C. The gap of 15.9C represents the fourth highest diurnal temperature range for February in this area back to 1959.

feb diurnal
Top 10 February diurnal temp ranges

 

Looking at the year as a whole the greatest range is 20.8C with the months of May and June the most likely to see the condition.

top 10 diunrals
Top 10 diurnal temperature ranges since 1959

 

A winter heatwave

It is 21 years ago this month that London and most of the southern half of the UK experienced a remarkably warm spell of weather during what had been a mild winter.

The spell, which saw the record warmest February day on the 13th (19.7C), satisfies the Met Office’s old criteria of a heatwave whereby the maximum temperature is 5C or more above average for five consecutive days.

While these spells are fairly common in summer they are very rare during a meteorological winter. During the last 60 years the only other periods to have experienced a heatwave in winter are December 1966 and 2015.

Weather charts for this week look remarkably similar though, according to the latest forecasts, values will be nothing like they were in 1998.

Since this was published this 2019 spell has satisfied the Met Office criteria. But the anomalies are not yet as impressive as 1998.

1998 2019

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feb 1998 maxes

 

 

January 2019: rather cold, dry

January was most notable for being on the cold side, in contrast to December.

The mean temperature finished 4.1C, 1.1C below average, over 2C colder than last January.

Some 32.9mm of precipitation was recorded, 62 per cent of the 1981-2010 average, about half what fell last year, the driest January since 2006

Some 55 hours of sunshine were recorded, that’s 109 per cent of average, sunnier than last year.

Fourteen air frosts were recorded.

There were four days where snow fell but only one day of snow lying, 1cm on 23rd.

To view full stats follow this link:http://1drv.ms/1kiTuzv

My winter forecast went a bit awry in December – I predicted a mean of +0.8C, the outcome was +1.7C. January has been much better, I predicted -1.2C, the outcome is -1.1C! Also… “And another cold spell end of January into the first week of February?”
For February I predicted a mean of -1.7C. The current pattern to continue and signs on the EC of a more robust cold spell with air supplied by a Scandinavian high?