Weather headlines are popping into the news at the moment, with some taglines wrongly indicating Atlantic hurricanes are on the way to the UK! Let’s clear this up!
We will not experience a hurricane any time soon in the UK. Hurricanes transition to extratropical cyclones by the time they hit the UK, and instead ‘arrive’ in the UK in a very similar form to the usual Low pressure systems the UK gets, perhaps bringing a little warmer (Tropical maritime air) and more moisture than normal. The storm making the headlines is forecast to move over the UK late Friday 3rd and into Saturday 4th October 2025 and is expected to be very strong. Due to the strength it has now been named Storm Amy to make people aware of the risks it poses and the actions needed to stay safe.
Currently there are two Tropical cyclones located off the east coast of the United States of America (Figure 1). In the North Atlantic Tropical cyclones are called hurricanes, a term also used for tropical cyclones in the north-eastern and central Pacific. These hurricanes are large low-pressure systems that are transporting large amounts of heat and moisture poleward from more Tropical regions, contributing to the atmosphere’s natural processes to balance out the energy imbalance between the Equator and the Poles.
Hurricane Imelda and Humberto are both (as of 3pm 1st September 2025) categorised as Category 1 hurricanes on the Saffir-Simpson scale. Imelda is currently positioned where conditions are still favourable for the hurricane to strengthen to become Category 2 hurricane later today.
Humberto is in a slightly later stage of its lifetime, having previously peaked at the very top of the Saffir-Simpson scale, Category 5, earlier in the week when sustained winds reached 160mph winds (Figure 2). This classified Humberto as a major hurricane.
Now Humberto is moving into unfavourable environments for hurricane development and is expected to weaken. It will then go through a process called extra-tropical transition by the end of the day and it is this process which ensures a hurricane will not be hitting UK shores. It essentially transitions the hurricane to what we know as a ‘normal’ area of low pressure.
Having two hurricanes in the North Atlantic at the same time is not unusual, and the occurrence of major hurricanes is become less unusual. One known impact of climate change is having a higher proportion of intense tropical cyclones or major hurricanes. This does not mean we are having more hurricanes per year overall, it is the intensity in windspeeds and precipitation that is increasing.
However, the proximity of the two hurricanes is unusual. These two cyclones rank 10th in the list of closest named storms since 1966, with 582 miles between the hurricanes. When cyclones get close enough, less than 900km (~560miles), their wind fields can interact with one another in a process called the Fujiwhara effect. The Fujiwhara effect can cause cyclones to ‘dance’ or rotate around one another and sometimes even merge. Imelda and Humberto are not projected to merge but are interacting.
How will these hurricanes impact our weather in the UK?
We know from our understanding of the Global Atmospheric Circulation that there are westerly winds in the mid-latitudes and because of this the now hurricanes, but future ex-hurricanes, will be carried across the Atlantic towards the UK (Figure 3).
Humberto, once downgraded to an extratropical cyclone is expected to make its way over the Atlantic in very favourable locations for deepening the Low pressure and therefore strengthening the storm.
When on the western side of the Atlantic, ex-Tropical Humberto is expected to be in a right jet entrance (where the jet stream is speeding up or accelerating), and as it approaches the UK it is expected to be in the left exit region of the jet, both places that encourage rising motion, a reduction of air mass in the centre of the system and therefore cyclogenesis or deepening of a storm.
We can see by Friday evening (Figure 4) and into the early hours of the morning that there are very tightly packed isobars around the system, indicating the Low pressure, but also the extremely high winds that this storm will bring to the UK. Even after the centre of Storm Amy has moved NE of the UK on Saturday (Figure 5), the isobars are forecasted to stay tightly packed together and the strong winds will persist for longer.
Due to the forecasted intensity of this storm, the Met Office has named it Storm Amy, using the storm names that were announced earlier in the year. This will be the first named storm of the year.
Exploring hurricanes and storms in your classroom
If you would like to explore hurricanes like Humberto and Imelda and Low pressures like Storm Amy during the events or retrospectively earth.nullschool is a great tool to use.
This interactive globe shows numerous atmospheric variables through many different layers in the atmosphere and also extends to ocean waves and currents.
The surface winds show the Low pressure systems well, with the rapid cyclonic winds (anticlockwise winds in the Northern Hemisphere) standing out clearly. In order to do this go to the website and:
- Click on ‘Earth’ in the bottom left of the page to bring up the menu
- Select the variable and layer you would like to look at (a reminder that the lower the pressure, the higher up in the atmosphere). For surface winds, make sure Mode = ‘Air’, Animate = ‘Wind’, and Height = ‘Sfc’. If the overlay = ‘Temp’ it shows nicely that these storms are transporting warmer air poleward.
- Select the time. Click the calendar icon in the ‘Control’ panel and select your date.
- Once you have the data you want, you can then scroll through the time with the arrows in the ‘Control’ panel and see the progression of the storms.
