High terrain extending across Italy and central Europe yield a challenging environment for weather forecasting in the northern Adriatic Sea, especially during the winter months. The Alps, 120 miles wide with several peaks over 15,000 ft, block colder air to the north and often deflect it to the east over the Balkan States. The cooler air accumulates over the Balkan Peninsula, eventually reaching the height of the mountain passes. This induces a Bora, a local downslope wind effect that is common and at times violent during the cold season, usually from October through March. The Bora is one of two local winds that impact marine customers in this region. The other being Sirocco winds, a strong southeast wind, which often build over the course of a couple of days ahead of a Bora or impending low pressure system and is usually forecast with less uncertainty.
The Bora flows from the northeast through gaps in the Dinaric Alps and may be very localized or extend as far south as Malta. In the most extreme Bora events, wind gusts over 100 knots have been reported. These winds are typically not short-lived and may persist over the area for several days or more.
Italy’s fall season may have just begun, but portions of the Adriatic Sea have already experienced effects from a strong Bora. Over the weekend, a cold front and preceding trough moved southeast across the Adriatic and high pressure intensified behind it. This produced widespread cloud cover and showers and thunderstorms across the region early Monday morning. The strong Bora followed Tuesday into Wednesday. A station along the western shore recorded a wind maximum of 29 knots near midnight LT Wednesday with a fresh to strong northeast breeze continuing through the early morning hours. It’s not uncommon for coastal sites to experience diurnal variations during Bora events.
Many offshore oil companies rely on Wilkens Weather forecasts and lightning alerts in the Adriatic Sea to ensure the safe completion of offshore installations and rig moves. Accurate forecasts of the timing, strength, and duration of Bora events are especially important to these customers.
About Wilkens Weather Marine Weather Forecasts
Daily marine weather reports include a weather synopsis, severe weather summary when applicable, forecast confidence level, and up to a 10-day forecast of weather conditions at a site-specific location or along the course of a route. Standard forecast data includes
- Weather conditions (rain, squalls, fog, etc.)
- Wind speeds and gusts
- Wind wave height and direction
- Swell height, direction, and period
- Significant wave height
- Maximum wave height
- Air temperature*
- Cloud height and visibility*
*Available upon request.
Marine weather reports may also be supplemented with EnsembleSimulator, a probability-based forecast that clearly identifies working weather windows, and Ocean Current Guidance Forecasts (OCGF), which provide awareness of ocean current conditions and their expected changes over the next several days.