Monitoring and forecasting the UK climate and its meteorological changes with analysis

UK Climate Forecasting and Analysis

Climate Change   UK Weather   North Atlantic   Reports & Analysis   Jet Stream   Flooding   Air Quality

The images Courtesy of NOAA Star show the satellite image of the US Atlantic Coast and the Lower Level Water Vapour on Friday 2 May at 07.11 hours

Due to the rotation of our planet and the Coriolis effect in the Northern Hemisphere winds are blown to the right across the North Atlantic to Ireland the UK and Scandinavia so we have to look at the weather in North America and the direction of the Polar Front Jet Stream. The Coriolis effect increases in strength the nearer you get to the poles and is responsible for large cyclones or depressions. The weather in the North Atlantic is influenced by the 23.4° tilt in the axis of the Earth as the seasons are caused by variations in the angle of the sunlight hitting the Earth and are one of the major causes of Atlantic storms.

We will research these meteorological changes and analyse data which effect the UK. Why is lower-level water vapour band imagery important? The 7.3 µm “Lower-level water vapour” band is one of three water vapour bands on the ABI. It typically senses farthest down into the mid-troposphere in cloud-free regions, to around 500-750 hPa. It is used to track lower tropospheric winds, identify jet streaks, monitor severe weather potential, estimate lower-level moisture (for legacy vertical moisture profiles), identify regions where the potential for turbulence exists, highlight volcanic plumes that are rich in sulphur dioxide and track Lake effect snow bands.

The Atlantic Ocean is the second-largest of the world's oceans. With a total area of about 41,100,000 sq miles it covers approximately 20% of the Earth's surface and about 26% of its water surface area. The average depth of the Atlantic with its adjacent seas is 3,339 metres or 10,950 ft without them it is 3,926 metres or 12,880 ft. The greatest depth is the Milwaukee Deep at 27,500 ft in the Puerto Rico Trench. The Atlantic's width varies from 1,538 nautical miles between Brazil and Sierra Leone to over 3,450 nautical miles in the south. The principal feature of the bottom topography is a submarine mountain range called the Mid-Atlantic Ridge which is moving at 2.5 cm per year. It extends from Iceland in the north to approximately 58° South latitude reaching a maximum width of about 860 nautical miles. The Mid-Atlantic Ridge separates the Atlantic Ocean into two large troughs with depths from 12,000–18,000 ft. Transverse ridges running between the continents and the Mid-Atlantic Ridge divide the ocean floor into numerous basins. Some of the larger basins are the Blake, Guiana, North American, Cape Verde and Canaries basins in the North Atlantic. A great rift valley also extends along the ridge over most of its length. The depth of water at the apex of the ridge is less than 8,900 ft in most places while the bottom of the ridge is three times as deep. The Atlantic Ocean is a major source of atmospheric moisture through evaporation and traps around 30% of the carbon dioxide emitted into the atmosphere by human activity. The waters circulate in a clockwise direction. The Gulf Stream carries more water than all the world’s rivers combined and has it moves north its salinity increases. The Sargasso Sea has above average salinity.

UK Climate Forecast  38 Union Street  Grantham  Lincolnshire NG31 6NZ   

Oceanic currents are driven

 by three main factors

1. The rise and fall of the tides. Tides create a current in the oceans which are strongest near the shore and in bays and estuaries along the coast. These are called "tidal currents." Tidal currents change in a very regular pattern and can be predicted for future dates. In some locations strong tidal currents can travel at speeds of 8 knots or more.

2. Wind. Winds drive currents that are at or near the ocean's surface. Near coastal areas winds tend to drive currents on a localised scale and can result in phenomena like coastal swells. On a more global scale in the open ocean winds drive currents that circulate water for thousands of miles throughout the oceans.

3. Thermohaline circulation. This is a process driven by density differences in water due to temperature and salinity variations in different parts of the ocean. Currents driven by thermohaline circulation occur at deep and shallow ocean levels and move much slower than tidal or surface currents. Currents affect the Earth's climate by driving warm water from the Equator and cold water from the poles around the Earth.

The Florida current can be considered the "official" beginning of the Gulf Stream System. It is defined as that section of the system which stretches from the Florida Straits up to Cape Hatteras. It is a key component of AMOC with low salinity. The current was discovered by Spanish explorer Juan Ponce de León in 1513. The Florida Current receives its water from two main sources, the Loop Current and the Antilles Current. The Loop current is the most significant and can be considered the upstream extension of the Gulf Stream. The Gulf Stream together with its northern extension the North Atlantic Drift is a warm and swift Atlantic ocean current that originates in the Gulf of Mexico and stretches to the tip of Florida and follows the eastern coastlines of USA up to Newfoundland before crossing the Atlantic Ocean to Ireland UK and Western Europe making the region about 5 C warmer.

North Atlantic Ocean - Friday 2 May : A middle to upper level trough extends W-SW across the Hispaniola. This feature is creating unstable atmospheric conditions to the south and east of it, and supporting active weather. Scattered showers and thunderstorms are occurring S of 22N between Hispaniola and 63W. A 1014mb low pressure has been analysed near 28N51W. A surface trough extends southwestward from the low pressure to the eastern Caribbean. Scattered to numerous showers and thunderstorms are active from 20N northward to 31N between 42W and the low pressure at 51W. Northeast of the low, stationary front continues from 26N61W to beyond 31N53W. Northwest of the area, a 1021 mb high is centred near 31.5N72W. The pressure gradient between the high and these features is producing moderate to fresh NE winds to the west of the low and surface trough, with strong NE winds north of the front between 55W and 61W. Seas 5 to 7 ft prevail to the east of the Bahamas. Gentle winds are noted N of 29N and also N of the Bahamas, where seas are 3 to 4 ft. Farther east, 1025 mb high pressure is east of the front near 32.5N34W, and a 1004 mb gale center is north of Madeira near 36N11.5W. This pattern is supporting a large area of moderate to fresh N to NE winds and 8 to 13 ft seas over the eastern Atlantic north of 20N and east of 32W, reaching near gale force on the south and eastern side of the low. Moderate to fresh trade winds prevail between 32W and the central Atlantic surface low and trough. Seas across this region are 5 to 8 ft in NE swell. For the forecast west of 55W, a stationary front and a surface trough, with a weak low along it, will persist over the central Atlantic between 50W and 60W over the next 48 hours. Fresh to strong SE to S winds and building seas to rough are expected first over the E side of the trough on Fri, then over the NW part of it on Fri night and Sat due to the pressure gradient between the trough/low and high pressure to the N. The low should dissipate by Sun, and the trough is forecast to drift westward over the forecast waters early next week. An area of fresh to strong easterly winds and rough seas will persist near the northern end of the trough axis affecting mainly the NE waters. Looking ahead, a weak cold front will emerge off the northeast Florida coast late Sat night into Sun where it may dissipate.

Monsoon Trough : The monsoon trough axis enters the Atlantic near 08N13W and continues southwestward to 03.5N26W. The ITCZ extends from 03.5N26W to 00N46W. Scattered moderate convection is noted from 02N to 07.5N between 13.5W and 22W.

Caribbean Sea : For the forecast, high pressure over the western Atlantic combined with the Colombian low will support fresh to strong northeast winds through the Windward Passage tonight. At the same time, fresh northeast winds are expected south of the Dominican Republic, mainly near Cabo Beata, and in the Lee of Cuba. Fresh to strong northeast winds will materialize through the Windward Passage again Fri night. Moderate to fresh winds will pulse north of Honduras, increasing to fresh to strong Tue night. Unsettled weather is expected to continue over most of the eastern Caribbean into the weekend. Otherwise, rather quiet conditions are expected over the basin into early next week.

Gulf of America : For the forecast, high pressure will be the main feature controlling the weather pattern across the basin through tonight. The associated pressure gradient will maintain moderate to fresh east to southeast winds over the basin through Sat morning, except gentle to moderate in the NE Gulf. East winds will pulse to strong speeds north of the Yucatan peninsula and over the Bay of Campeche tonight and Sat night in association with a diurnal trough. Moderate to fresh E winds and moderate seas are expected across the Straits of Florida through tonight. A weak cold front will reach the northern Gulf early Sat before shifting east of the basin Sun night. High pressure will then build southward across the Gulf leading to mostly moderate to fresh easterly winds over most of the forecast zones early next week, increasing to fresh to strong over the western Gulf by early Tue as the gradient tightens.

Mid Atlantic Waters

A high pressure ridge will persist across the southern waters through Sun night. Meanwhile, a warm front extending SE from northern New England to the Outer Mid-Atlantic Waters this morning will lift lift NE through the northern waters this morning before passing N and NE of the area this afternoon. A cold front will very slowly approach the coast from the NW Sat into Sat night. Weak low pressure will develop over the interior Mid-Atlantic on Sun and persist through Mon night, with a stationary front extending NE from the low across Georges Bank. A cold front extending S from the low will stall along the coast through Tue before finally pushing offshore into the northern and central waters Tue night.

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