Commanders’ Weather Corporation
Sunday, 1845utc, 12.09.2007

From: Commanders’ Weather Corporation
Route:54° 47S, 64° 24W to Buenos Aires
Est position: 53° 32S, 73° 30W
0200utc Sunday, December 9, 2007
Prepared: 1845 utc Friday, December 7, 2007

Summary

Unsettled/active and at times fairly rough weather for heading to Buenos Aires through the middle of next week

The current weather map features a very deep gale center just east of the Antarctic Peninsula with a pressure near 956mb!

A strong cold front extends northward from this gale to near the Falklands.

A very strong area of high pressure is centered well to the northwest of the area in the southeast Pacific near 39s/102w with a pressure near 1040mb!

There is a significant pressure gradient between the gale to the southeast and the high to the northwest with your area currently caught in the worst of it.

Expect SSW to SW winds to continue on the strong side through today with speeds of 30-40 knots, coming down a bit by this evening to around 20-30 knots.

The gale to the southeast will not be in a hurry to leave with a huge upper level trough remaining nearby and there will be weaker surface disturbances rotating around the trough into this weekend.

One of these disturbances will pass the area tonight turning into a fairly potent low east of the Falklands on Saturday.

Expect W winds when you depart tomorrow morning around 15-25 knots, then winds will back into the WNW later tomorrow ahead of another trough/cold front and they will increase to 20-30 knots.

Later Saturday night into Sunday will be a rough period behind this cold front as yet another low spins up along the front to the east of your route with SW winds increasing to 30-40 knots!

Expect winds to ease some later Sunday as the tightest gradient moves east of you, but still around 20-30 knots.

The gradient will increase a bit again later Sunday night into early Monday with SW winds increasing to 25-35 knots.

A period of headwinds are possible on Monday ahead of the next trough with winds clocking to NNW with speeds around 15-25 knots.

Yet another trough will approach Monday night with another period of headwinds possible before winds again back to SW behind it and not to sound like a broken record, but there may be another trough approaching late Tuesday.

Seas will start out fairly reasonable due to being sheltered by the eastern tip of South America, but as you get further north you will see increasing SW swell and there will be plenty of wind wave chop to go along with it.

Seas may reach as high as 10-15 feet later Sunday into Monday.

General weather will remain very unsettled through the forecast period with a chance of showers and squalls just about everyday with all the troughs moving through.

Routing

Suggest staying a bit west of rhumb line to avoid longer periods of N headwinds and somewhat lower seas.

Estimated positions below.

Wind forecasts
Wind directions are TRUE, wind speed in kts, and time is UTC
Offshore seas WSW 15-20 feet in exposed areas, largely swell

Sat Dec 8
12: 260-280/15-25 depart
18: 280-300/20-30
Weather: Variable clouds with a chance of squally showers
Seas 5-9 feet, SW to W swell and wind wave chop

Sun, December 9
00: 300-320/20-30
06: 220-250/25-35
12: 210-230/30-40 near 51 15s/64 30w
18: 220-240/20-30
Weather: Mostly cloudy with showers and squalls
Seas building to 10-15 feet, increasing SW swell and wind wave chop

Mon, December 10
00: 200-230/20-30
12: 220-240/25-35 near 47 30s/64 10w
Weather: Variable clouds with scattered squally showers
Seas 10-15 feet early, then decreasing to 8-12 feet, SW swell and wind wave chop

Tue, December 11
00: 330-360/15-25
12: 230-260/15-25 near 44s/63w
Weather: Variably cloudy with a chance of showers and squalls
Seas decreasing to 5-9 feet, confused swell

Wed, December 12
00: 010-040/15-22
12: 290-320/15-25 near 40 30s/60 30w
Weather: Variably cloudy with a chance of showers and squalls
Seas mainly 5-9 feet, confused swell and wind wave chop

Location 51° 50S, 63° 15W
Sunday 12.09.2007

The Schooner Maggie B was at 51° 50S, 63° 15W at noon on December 9th. We were running north at 8-12 knots before a Southerly gale. The skies are clearing up and the rain has mostly stopped. It is a little warmer, which isn’t very warm. We have the main up with three reefs, the fore up full and the jib about half reefed. The wind waves are developing into small swells that we surf from time to time. Jorge, the Furuno autopilot, is doing a great job.

At noon the wind was only 15 knots and some might have been tempted to break out our three-reefed main, but the barometer was down at 984 millibars and we knew to be ready for the next blow. Rather than heading straight for Buenos Aires, we are edging somewhat in towards the Argentinean coast to reduce somewhat the height of the waves and to hopefully avoid a northerly that may come in the next few days with the next front. The new Commanders Weather should be posted soon so all can see the trade-offs we are making.

We have come 408 NM since Puerto Williams and have 1056 to go to the Buenos Aires.

We are all looking forward to leaving the Furious Fifties behind for the relative calm of the Roaring Forties.

All is well.