T-Sum

Tsum weekly summary

Report 4. Week Ending  12 Feb 2007

Last week’s cold weather brought snow to large parts of England and Wales. The melting snow and rainfall at the start of the week has caused soil conditions to deteriorate significantly over the British Isles, and ground conditions are now considered heavy.  The colder weather last week also slowed the advancement of T-Sum values.  With the exception of the southern English coastline and parts of the Welsh coastline, where T-Sum values have exceeded 300, most of England has T-Sum values ranging between 220 and 280.  For northern England and most of central Scotland, T-Sum values remain below 200, ranging from the low to high 100’s.

This week’s weather will be milder and wet, with the potential for some heavy downpours during the week.  The forecast rainfall will add further to the excess soil moisture, and exacerbate the heavy soil conditions. Nevertheless, T-Sum values are expected to make significant advancements this week due to the milder weather. T-Sum values are expected to exceed 400 in some southern coastal areas. Other coastal areas in England, Wales and Scotland are forecast to approach the late 200’s and low mid 300’s. Parts of southern England are also expected to break T-Sum 300, whilst for the majority of England and Wales, T-Sum values are likely to reach the late 200’s. For extreme northern England and central Scotland, T-Sum values are forecast to range from the mid/high 100’s to low/mid 200’s.

Report 3. Week Ending  5 Feb 2007

For most of last week, the British Isles was under the influence of dry and rather mild weather for this time of year. The week ended with colder weather, due to the arrival of a high pressure system. The dry conditions experienced over the past week have brought more favourable soil conditions, whilst the mild temperatures have advanced T-Sum values in all regions.

Southern and Welsh coastal areas now have T-Sum values approaching the low 300’s, whilst areas in southern, western, eastern and central England have exceeded the T-Sum 200 threshold.  T-Sum values in northern England range from the mid 100’s to low 200’s, whilst in central Scotland T-sum values range from low 100’s to mid 100’s. Due to the warm January, T-Sum values are much more advanced than this time last year, with T-Sum values being approximately 50-100 degrees higher.

This week it is expected that a cold Arctic airmass will dominate the weather in the British Isles. As a result temperatures are expected to be cold, with temperatures being more representative of British winter conditions. The dry weather should continue until mid week, when rain and snow may spread northwards from the south-west.  Consequently, T-Sum values are expected to advance at a slower rate than last week in all regions, increasing by approximately 10 to 20 degrees.

Report 2. Week Ending 29 Jan 2007

Last week’s high pressure brought colder temperatures to the British Isles, with icy conditions a feature for most parts of the UK. Despite the cold snap, temperatures remain at near record temperatures for January, and the high T-Sum values over the British Isles reflect this.

T-Sum values have now reached the low 200’s in parts of the southern counties and southern, eastern, and Welsh coastal areas. Most of central, eastern and north west England and Wales have T-Sum values ranging from 170-195. Further north, colder temperatures have kept T-Sum values 140-160, whilst in parts of central and northern Scotland T-Sum values range from mid 60’s to 100’s.

This week we can expect the weather to be dry in the early part of the week. The drier conditions may improve the soil conditions for the more freely draining soil types. T-Sum values are expected to advance by 30-50, taking most of England, Wales and Northern Ireland over the 200 threshold. This advancement is forecast to produce T-Sum values of approximately 200 to 250 for these areas, although in some southern coastal areas T-Sum values are expected to approach 300. The colder regions of Northern Scotland have T-Sum values ranging from the high 90’s to low mid 100’s, whilst further south of this T-Sum values are expected to range from the mid to high 100’s.
 

Report 1. Week Ending 22 Jan 2007

Following one of the warmest autumns on record, the mild weather has continued right into the New Year. So far in January, temperatures have been running between a remarkable 3 and 5 oC above normal.  This has boosted T-Sum values right across the country.

Along with the warm conditions we have also had above normal rates of rainfall with October, November and December all recording above normal totals.  This has left soils across the UK standing at field capacity and ground conditions are poor.

Currently, in the warmer southern counties T-Sum values lie between 170 and 190. Central England, parts of northern England, Northern Ireland and Wales have lower T-Sum values, producing values between 125 and 170. The colder, inland parts of northern England and Scotland have T-sum values in the range of 60 to 120.  Higher values are found for coastal areas around the British Isles.

High pressure is set to dominant over the British Isles this week bringing colder weather. T-Sum values are forecast to reach and exceed 200 in parts of southern England, and the Welsh/English coastline. Most of central, eastern and northern England and Wales will also see an increase in T-sum values to the late 100’s and in some places low 200’s.  The colder northern areas values are forecast to remain less than 100.