Baltic Sea under high pressure. Calm end of April with episodic wind increase

As meteorologist Mariusz Jasłowski notes:

- This is a classic spring high-pressure pattern - it stabilises the atmosphere but does not eliminate local contrasts, especially in the coastal zone. The Baltic responds very quickly in such setups, particularly to land–sea temperature differences.

Synoptic overview

The region remains under the influence of a persistent high-pressure system suppressing frontal activity and maintaining dry conditions. Atmospheric pressure stays elevated and stable, ranging between 1026–1031 hPa. No precipitation is expected during the analysed period.

27 April: calm start with a cooler maritime influence

The period begins with variable cloud cover, ranging from low to moderate with occasional clear spells. Daytime temperatures reach 8–14°C. Winds blow from the northwest, generally light to moderate, but locally stronger near the coast and over open water, with gusts up to around 40 km/h.

Mariusz Jasłowski explains:

- This is a typical spring sea–land interaction effect. Even under a stable high, the Baltic enhances local wind speeds along the shoreline due to temperature contrasts.

Sea conditions in the Gulf of Gdańsk are moderate, with short-term wave build-up near the coast.

28 April: the most stable day of the period

Tuesday brings a clear improvement in weather conditions, with predominantly sunny spells and only minor cloud cover. Temperatures rise to 9–16°C. Winds remain moderate, blowing from the west and northwest.

According to Mariusz Jasłowski:

- This is the most organised day of the entire period. The high-pressure system is fully in control, delivering very favourable conditions both on land and at sea.

A particularly good window for both recreational sailing and coastal activities.

29 April: increased wind dynamics

Wednesday brings a noticeable increase in wind speed due to a strengthening pressure gradient over the region. Cloud cover becomes moderate to locally extensive. Temperatures remain between 10–17°C. Winds are variable, predominantly from the north and northwest, with gusts reaching 50–60 km/h over open waters.

- This is not a frontal passage, but a typical atmospheric response within a high-pressure regime combined with thermal contrasts. For mariners, this means more demanding conditions, especially offshore, said Mariusz Jasłowski.

Short-lived deterioration in sailing comfort is possible in the Gulf of Gdańsk.

30 April: warmer and calmer ahead of May

The final day of the month brings gradually improving comfort and a noticeable rise in temperatures. Cloud cover remains low to moderate. Temperatures reach 11–18°C. Winds weaken, shifting between southeast and west.

As Mariusz Jasłowski summarises:

- This is a transitional day towards a warmer, more convective early May pattern. The atmosphere begins to show increased thermal instability, but without any thunderstorm risk yet.

Maritime and coastal conditions

The entire period is characterised by dry weather and generally good visibility. Wind variability remains the primary factor influencing sea conditions, with the most demanding phase expected on 29 April.

Key points:

• no precipitation throughout the period
• generally good visibility
• episodic strong wind gusts
• locally rough seas with northerly flow
• best windows: 28 and 30 April
• more demanding sailing conditions: 29 April

- This is a typical spring Baltic pattern - calm in the broader sense, but with local features that require attention, especially offshore, concludes Mariusz Jasłowski.

The end of April along the Polish Baltic coast will be dominated by a stable high-pressure system, ensuring dry and relatively mild conditions. Despite the overall calm pattern, intermittent wind surges highlight the dynamic nature of the Baltic environment and the need for continuous situational awareness, particularly in coastal waters and offshore sailing zones.