Portugese phenomena?

[Ocean Hound]

Whilst sailing down the Portugese coast in the summer to Cape St Vincent we came across strange weather phenomena. 5-6 miles offshore, wind in the N/E 15-20kts when a purple haze started to appear on the S/board bow, ocean side, we then had a short rain storm which deposited a lot of sand followed by blasts of really hot air, the cycle continued with increases in the wind speed, more rain, more hot air and then a rapid increase from 25kts to 35 to 40 to 50 in as much time has it has taken to type this which resulted in a knockdown, possibly a capsize had we not put in a 3rd reef earlier. We then experienced winds from the shoreside in excess of 60kts- quite terrifying in that 20 mins ealier we had been sailing just in shorts without lifejackets & lifelines. Any idea what would cause such a extraordinary phenomena -could it have caused by the heat in Central Spain and what would it be called? It lasted for about 45 mins?

 

[chinita]

Jimi Hendrix sang about it.

 

[Evadne]

Dust storm from Iberia or the Sahara desert? click here for an example.

 

[stiknstring]

Had a similar situation in July 2004, same place but thankfully nowehere near the same wind. Sea got up very rough indeed in the space of around an hour and stayed like that for several hours. Biggest seas I ever saw. Didn't see a dust haze but it went very grey and overcast (may have been a dust plume at higher altitude). I have been puzzling ever since how this came out of an otherwise beautiful day with blue skies - maybe you have now supplied the answer.

Other phenomena down that coast was a sudden and steep increase in wind at around 1400 hours every day. That is more explainable I guess (land heating etc), but the worst we had from this was going into Cascais at 39 kts. Not nice.

 

[iangrant]

Running along to the East of the Shipping Lanes off Finnistere TSS we had a sustained F8 for 24 Hours then for most of the nexy day 45 gusting 50 knots. Enormous sea in which we took the waves on the quarter with a hankie for a jib. At the bottom of the troughs the tops were much higher than the mast, too steep to carry on out course south so eased our way toward the coast. Within 12 hours it had eased to a force 5, then by dawn to force 0, with thick fog, the thickest I'd seen, but bright sunshine. Two days of very poor viz ' till we turned left for Villamoura, then the sun came out proper.

I reckon it's where an awful lot of Ocean meets an awful lot of land!

Cheers

Ian

 

[Richard10002]

Before our trip from Glasson to Lagos, someone here warned of substantially incresed winds blowing of headlands like Cascais and Cape St. Vincent... and they were right.

about 10 miles before turning left into Cascais the wind increased from about 15kts to 30kts+, then flat calm once we got well around the corner.

Ditto Cape St. Vincent, but less violent.

 

[Swagman]

IMHO not a Portuguese phenomena.
Suspect most who've gone round the Iberian Peninsula have had experiences with strong sea breezes afternoons (yup - due to hot land - colder water), or strong land breezes at night (yup - hot water - colder land) plus rising winds on headlands (definately happens) and / or dust being dumped in rainstorms.

I believe lots of dust can be carried up from Africa but more usually is carried off Iberian fields closer to shore suspended in clouds - until an unwary yacht comes along.

It is a bugger, as it usually leads to a major clean down of everthing afterwards. Mast / rigging / sails / deck / etc.

Sounds like you had a combo of all the above at one time, and pleased to know you came though with no damage.

JOHN

 

[Ocean Hound]

Thanks guys - nice to know we were not the only ones - and yes we had the high winds 40kts at Cascais and St vincent itself, but they were a breeze compared with this. We had about 3-4m swell beforehand that was completely flattened with the spume and spray, plus I thought wind turbine was going to take off or burn out as it sounded like jet engine on a test bed. Does anyone have a name for the phenomena- the usual meltem, kabatic winds etc don't seem to fit, particulalry as the shore there was relatively low?