Home / Weather News /

Trapped under pressure

10:00
29 October 2024

Anticyclonic gloom
Trapped under pressure

See how much cloud is forecast over the next few days on the WeatherRadar.

High pressure is in charge, but it's often cloudy and grey. Shouldn't high pressure bring sunshine?

We often associate high pressure with fine and settled conditions, whilst low pressure cloudy and wet. But that isn't always the case through the autumn and winter months.

Sometimes, cloud and moisture can get trapped under an area of high pressure, as we've seen in recent days. This leads to the aptly named term "anticyclonic gloom", or a "dirty high".

Low clouds or fog can become trapped as a cool area of high pressure moves over moist land. The moisture then evaporates, resulting in a deck of low clouds.

A temperature inversion, as explained in the video below, can also trap moisture, which can cause low level clouds or fog to persist.

The actual pressure value can have an impact too. A deep, dry high pressure system is far less likely to have any clouds at its core.

While it's frustrating to not see any sunshine, it also creates a surprisingly tough job for meteorologists.

This is because computer weather models struggle to calculate what will happen to the cloud cover, which can cause amplified errors at a larger scale.

Half-term weather forecastread more
More on the topic
Split weather map comparing two wind conditions over the Atlantic. The left side shows a powerful cyclone near the US East Coast, with a distinct eye surrounded by intense purple and red bands of strong winds. The right side shows calmer conditions, mostly green shading with lighter winds illustrated by white streamlines and small yellow patches. An arrow in the centre indicates the transition from storm to calmer weather.
Wednesday 10 September 2025

Since Erin

Hurricane season exceptionally calm
Flooded road with cars in the water. Next to it, a weather map with a warning symbol. Heavy rain causes regional flooding.
Tuesday 9 September 2025

Towns flooded

Heavy rain hits Europe
Red moon during a lunar eclipse in the dark night sky. The Earth's shadow colours the moon's surface copper red.
Monday 8 September 2025

The blood moon

Total lunar eclipse in all its glory
All weather news
This might also interest you
Wednesday 27 August 2025

Breakfast brief

Frontal system brings heavy rain
Mammatus clouds
Thursday 21 August 2025

Unusual view

Mammatus clouds over Ireland
Weather map of the UK and Ireland showing scattered showers with cloudy patches across much of the region, especially around western and northern areas. Sunshine symbols appear over London, Cardiff, and parts of southern England, while temperatures range from 17°C to 18°C in most places. Areas of heavier rain are visible over the Atlantic to the west.
Friday 29 August 2025

Breakfast brief

Unsettled conditions into the weekend
All articles
Weather & Radar

www.weatherandradar.ie

facebooktwitteryouTubeContact uslinkList
Privacy Policy | Legal info | Accessibility statement