GRIB Weather File Viewer - Case Notes Sailing our small boat from Levkas in Greece to Douarnenez in Brittany, France. The Route I work as a programmer and need to be able to communicate with my customers via a mobile phone so we wanted to minimise the time that we would spend out of mobile range. The most direct route from Greece to Gibraltar passes close to the Algerian coast, but we felt that, in the event of a problem or bad weather, it would be wiser to choose a route with better documented ports of refuge. We therefore decided that our route would be - Ionian to the S.E. tip of Sicily, along the south coast of Sicily, across to the S.W of Sardinia, then to the Balearics and on to the Spanish mainland. Then follow the Spanish coast past Gibraltar and into the Atlantic, directly to the Portugese Algarve, then up the Portugese coast and along the Spanish Atlantic coast, and finally directly across Biscay to Brittany. As this route would give us offshore passages of no more than 300 miles it meant that Grib forecasts would ideally suit our requirements. We only needed accurate 3 day forecasts and could use the longer range forecasts for planning ahead. Once near a coast we could refresh the Gribs via our GPRS link, and immediately plan the next few days in detail. The approximate planned route We set off from Levkas on 30th April 2006 and arrived in Douarnenez on 13th June, some 2400 nautical miles later. We decided to risk setting off early in the season, while the Mediterranean was still unsettled, in order to be able to make our way northwards up the west coast of Spain and Portugal before July, when the Portugese trade winds get established. The Start Shortly after we were launched at Preveza Marine on 28th April we made our way down to Vlikho on Levkas, arriving in heavy rain and little wind, and this persisted throughout the following day. We checked the Grib files and the local Navtex forecasts, both which indicated increasing winds from the south west over the coming days for the northern Ionian. As our plan was to sail first to the S.E. tip of Sicily the forecast was for wind on the nose for this leg. Closer examination of the Gribs showed that we could expect lighter winds to the west of us and light northerly breezes near the Italian coast, with fairly calm conditions near Sicily for the next 2 or 3 days but strong winds in the north Ionian and Adriatic. We decided to leave at first light on the 30th and to head westwards towards the area of lighter breezes. We left Vlikho at 0630 on the 30th and once clear of the islands picked up a F5 SSW wind. We had a fast and somewhat bumpy sail until around midnight when the wind died. We judged it well because we passed close to a thunderstorm early that night and could see and hear the storms to the north of us for the rest of the night. It took a while for the swell to ease but we then enjoyed windless motoring all the way to Sicily, arriving in Porto Palo on 2nd May at 1830. Using the Grib information proved to be very useful because it showed that conditions at Levkas were due to get worse (we later learned that they experienced thunderstorms and gale force winds for the next week) and that it was calmer and drier to the southwest. The Navtex forecasts, by their very nature, lacked the detail of where the "bands" of wind where and the details of what was likely to occur further than 24 hours ahead (the Greek "Further Outlook" shown in the Navtex just mentioned increasing winds and thunderstorms). Sicily to Sardinia We arrived in Sicily in glorious sunshine and with gentle sea breezes. We then made a mistake - we stayed for a day and a half. We met up with our neighbours who just happened to be camping on Sicily, and I picked up a call about work and had to do some hurried programming. The Gribs showed that a gale was brewing away to the south east off Libya and that the wind was due to get stronger in the channel between Sicily and Tunisia. We should have pushed on immediately and stayed ahead of the wind and, more importantly in this case, the swell. By the time we left Porto Palo we had a following F6 and a big and steep swell from the same direction that combined to make conditions very uncomfortable. The wind and swell eased a little by evening but another telephone call from a customer resulted in us stopping for the night in the safe harbour at Licata (it's no fun programming in a big sea!). We didn't leave there until the following afternoon and by then the wind had returned. We eventually gave up when we encountered thunderstorms, squalls and heavy rain and made our way into the harbour at Empodocles for the night. The Gribs showed that conditions should be much better once we got north of Sicily, so we left next morning at dawn and headed out further offshore into deeper water where the swell was much less, then on towards Sardinia. The weather for the crossing was much as forecast with very light winds and little swell. After much motor sailing, we arrived in Carloforte, on 8th may at 1250. Sardinia to Mallorca The Gribs showed that we could expect a strong NW wind for the next couple of days, then things should ease with a spell of light and variable winds, so we made the most of the stay and enjoyed the very friendly town of Carloforte. We left the marina at 0530 on the 11th May and were able to sail close hauled towards Menorca (the closest Balearic island) with the wind still around F5 and in quite rough seas. The wind and swell continued to ease throughout the day, as per forecast, and by 2030 we had to start motoring through lack of wind. By next morning the wind was still light and we decided to head instead for Mallorca. The wind came and went several times during the day but the swell continued to build from the south, getting very steep and up to nearly 3 metres by dawn on the 13th May. The conditions made it most uncomfortable as there was insufficient wind to steady the boat yet a big swell. We were surprised by the conditions as we had become used to Med sailing in Greece and Turkey where the swell was nearly always accompanied by wind and died within a few hours of the wind. The Gribs that are freely available don't include swell forecasts. We finally anchored in Andraitx, Mallorca at 1430 on the 13th. Mallorca to Gibraltar The Grib forecasts proved to be very useful on this leg of our journey because there were strong easterlies blowing to the south of us but a band of lighter north easterlies close to the Spanish coast. The Navtex forecasts played safe by overstating the wind force for the sea areas but we were able to make pleasant progress by keeping near the coast. We left Andraitx at dawn on the 14th and passed Ibiza at sunset, then continued through the night towards mainland Spain. We arrived off Benidorm at dawn next morning. The Grib files indicated that the strong easterlies that were affecting the Straits of Gibraltar would abate before building from the west, so we stopped overnight at Caleta Valez (17th), Fuengirola (18th) and Estepona (19th) to get a break and also to time our passage to arrive at the Straits when it was due to be calm. The timing was perfect, we arrived off Gibraltar at 1000 on 20th May in absolutely calm conditions. We passed through the Straits on a flat sea and arrived off Tarifa just as the westerly began to kick in. Tarifa to Portamao with a long stopover in Cadiz We had fully expected the journey to get tougher once we had left the Med. because we were heading northwards and the prevailing winds, at least until we reached Biscay, are from the north. We hadn't fully appreciated the affect of the swell, generated from gales many hundreds of miles away. At first we made good progress but ran into heavy seas off Cape Trafalgar. The seas were a combination of the swell from afar, the local wind (no more than NW F4) and the flow of tide and wind current creating overflows over the shallows which extend 20 miles or more westwards from the Cape. After a few hours of making no more than 3 knots to windward we turned about and sailed comfortably to Barbate We stayed there for 2 nights before setting off again. By now the forecasts were showing strong northerlies along the western coasts of Spain and Portugal for the next week and easterly (Levanter) gales for SW Spain within the next couple of days. We decided that we would head towards Cadiz, and decide when we were near whether to take refuge there or push on towards the Algarve where we could wait until conditions eased further north. We eventually waited in Cadiz for a whole week while the Levanter blew a full gale. The marina was almost empty of visitors when we arrived but soon filled up over the coming days. All the yachts apart from one other were heading south into the Med. The Gribs first showed signs of approaching favourable weather at least 5 days ahead, when it appeared that conditions in the area between the Algarve and Gibraltar would ease for just a couple of days before becoming strong from the west, but more importantly for us, the strong northerly winds affecting the west coast of Portugal and Spain would also become light and variable. We realised that we should leave Cadiz as soon as local conditions improved and make best speed northwards. We checked the forecasts each day will all other sources in an internet cafe. We eventually left Cadiz and sailed briskly towards Portugal. The wind died later that day so we finally motored into Portamao harbour in the early hours next morning. Portamao to Nazare Nazare to Povoa de Varzim Povoa de Varzim to Porto Nova Porto Nova to Cape Finisterre Cape Finisterre to Cedeira Cedeira to Vivero Vivero to Douarnenez The Bay of Biscay has a daunting reputation, and not without good reason, so we were careful to check the latest Grib forecasts before setting off. There was a quite complex weather situation with an intense low centred to the west of Finisterre with associated gale force winds. This was forecast to move relatively slowly to the NNE over the next few days, without filling. Another, less intense, low was away to our east and this was forecast to fill slowly. There were variable but mainly easterly winds off the French coast, gale force SW winds to our west but a band of lighter winds between the two systems and this, we decided, was the route that we would take. We didn't want to wait in the hope of getting more settled weather because the forecast indicated that the winds near the Spanish coast would increase within a few days. We felt that we had the option of travelling along the band of lighter southerly wind, and be able to go more to the west if we encountered strong easterlies or to the east in the event of strong south westerlies. We left Vivero marina at 1100 on the 9th June and set off towards Concarneau. We did adjust our course a little to the west and had a very comfortable passage with light favourable wind, arriving at Saint Evette (Audierne) at 0020 on 12th June. We departed that same night, and after an interesting passage through the Raz de Sein, arrived in Douarnenez at 0700 on 13th June. Mission completed! Summing Up Overall, we were delighted with our interpretation of the weather forecasts. The Gribs appeared to be more accurate in the Atlantic than in the Mediterranean, which is what one should expect as the Med is much more influenced by land effects. Any grief that we encountered was due to swell which isn't shown in the Gribs that we were using. We found that being able to plan up to a week ahead was invaluable, even in the knowledge that the conditions were likely to change to some extent over that period. On a day to day basis we checked the Grib forecasts against those received by Navtex and RTTY, just to confirm that nothing unexpected was materialising.