Welcome to the Weekly Weather Update – your guide to the world’s oceans and seas. Each week, we highlight key marine weather patterns and analyse unusual or significant weather events. From calm spells under high pressure to tropical cyclones forming in equatorial waters, and from jet streams steering oceanic storms to anomalies in sea-surface temperature that shape global climate patterns. Here’s what this week’s weather has in store.
Winter is coming, and low pressure systems are beginning to dominate the North Sea. On Tuesday, a weak mobile ridge will briefly move across the area. Behind it, a low will pass over Scotland and then track across the central and northern North Sea on Wednesday. By Thursday, this low will move eastward over southern Scandinavia, while another weak ridge crosses the North Sea.
On Friday, a deep low is expected to develop northwest of Ireland and remain there through the weekend. In the meantime, a secondary low may form temporarily near Shetland on Saturday. Early next week, the main low is likely to move toward the northern North Sea, while a new low passes over England.
On Tuesday, a weak ridge over the North Sea will bring a slightly stronger easterly to southwesterly flow. Winds over the central and southern parts of the sea are expected to increase to 25–35 knots, with local gusts reaching 40–45 knots. As a result, wave heights will build to around 2.5–4 meters.
The previously mentioned low will move across the North Sea on Wednesday, bringing increasing winds and waves over much of the region, particularly across the central and eastern areas on Wednesday and Thursday. Winds are expected to rise to 25–35 knots, with gusts locally reaching 45–50 knots. Wave heights may increase to around 2.5–4 meters.
Later on Thursday, a brief period of calmer weather will develop over the North Sea under the influence of another mobile ridge. However, conditions will turn unsettled again on Friday as a low pressure system northwest of Ireland sends strong frontal troughs across the area through Friday and Saturday. This will bring unsettled conditions to the entire region.
On Friday, winds are expected to increase to 25–35 knots over the southern and central North Sea, while stronger winds of 40–45 knots are likely over the northern North Sea and along the southern to southwestern Norwegian coast. Wave heights will build to 2.5–4 meters in most areas, reaching 5–7 meters in the north.
By Saturday, winds will ease slightly, generally ranging from 25 to 35 knots, with occasional gusts up to 40–45 knots in the northernmost areas. Wave heights are expected to be 2.5–4 meters, locally reaching up to 5 meters in the far north (see Figure 1).
On Sunday, conditions will be calmer, though winds are still expected to reach 25–30 knots over the central and northern North Sea. Wave heights will generally be 2.5–4 meters, increasing to 4–4.5 meters in the far north.
Overall, weather conditions across the North Sea remain highly changeable, with only brief periods of calmer weather. In general, the region will experience unsettled conditions, with some areas approaching stormy levels.
This week, attention turns to the Indian Ocean as well, where two notable systems warrant closer observation.
Tropical Storm Montha, with winds of 45 knots, is currently located in the western Bay of Bengal, moving northwest. The storm is expected to maintain its intensity until Wednesday morning as it makes landfall along the eastern coast of Andhra Pradesh. Later on Wednesday, Montha is forecast to weaken to 25-20 knots and is expected to further downgrade to a tropical depression as it moves further inland (see Figure 2).
In the Arabian Sea, a tropical depression is expected to persist over the coming days. While there is a small chance it could intensify, it is important to monitor forecasts regularly to stay informed.
As expected, unsettled and even severe weather has developed across the Caribbean. Major Hurricane Melissa, located south of Jamaica with maximum sustained winds of up to 150 knots, is forecast to pass near the island on Wednesday. The hurricane will gradually weaken during the day, with winds decreasing to around 120–90 knots.
Melissa is moving slowly northeast and is expected to cross eastern Cuba later on Wednesday, weakening to a Category 2 hurricane afterward. With winds between 85 and 80 knots, the system will continue northeast across The Bahamas from late Wednesday into Thursday.
Afterward, Melissa will move further into the Atlantic, gradually losing strength. It is expected to downgrade to a tropical storm by late Saturday or Sunday (see Figure 3).
With the summer season over, low pressure systems are increasingly dominating the North Sea, bringing changeable and unsettled weather. Elsewhere, notable activity continues around the globe. In the Bay of Bengal, Tropical Storm Montha is expected to weaken to a tropical depression soon enough. Meanwhile, Major Hurricane Melissa continues to impact the Caribbean Sea, moving slowly northeast while gradually weakening.
To stay updated on the current weather, please monitor your weather reports or contact our duty forecaster! And, as always, stay safe!
We plan to post this Weekly Weather Update on our Infoplaza for Marine Weather Operations LinkedIn page as well. This is also the place where we will share other insightful marine weather articles, so be sure to follow us to never miss an update.