The Waiting Game

Weather Watch: A long wait for the optimal conditions to make the passage to Greenland.

We’ve been enjoying Labrador, but consider it an appetizer, increasing our desire to get to Greenland. Labrador has given us a chance to "practice" with ice bergs and their smaller offspring, get accustomed to using our SONAR for navigation in cold water (it works much better in cold, dense mediums), and attempt to become familiar with the weather patterns in this part of the world.

We are used to being able to quickly come to grips with the weather, find what we need in short order, and be off. We are not finding things so easy for this short passage.

The key is visibility for bergy bits, the small offspring of icebergs. These lie mostly sunken, and are not easy to pick out. But they are big enough to do substantial damage to props, or worse. Our major concern is with too much wind and white caps. The white caps look a lot like small pieces of ice. We also need some degree of atmospheric clarity – at least half a mile at sea level.

As we have mentioned before, what we are looking for is a weak high pressure system. This will generate clear air. But if it is a strong high, with more than 17 knots of wind, the white caps will hide things we’d like to see. Southerly quadrant winds typically bring lower visibility, but we would trade some of this lowered visibility for lighter winds.

The weather hereabouts is influenced by a variety of factors with which we are not familiar. Between the higher latitude, proximity to the polar weather generators, and compressed topography with Greenland, it is hard for amateurs and professionals alike to figure accurately. The weather models also tend to diverge more than we are used to.

While on the boat, without wifi, we are limited to the NOAA Marine Prediction Center weather faxes received via radio, and GFS or NGPS weather models which we get on Sailmail (Sailmail is working great this cruising cycle).

The past week has seen some lovely weather on the Labrador side of the pond, but gales around Southern Greenland.

To help us figure out when to depart we have asked Rick Shema (www.weatherguy.com) to assist us in picking a departure date.

To recap, the parameters from our perspective are:

  • 700 miles from our present location on the Labrador coast to Nuuk, Greenland, including an allowance for two dog legs in course to depart/approach coastlines at more or less a right angle to reduce period in ice.
  • Two nights when we are hove to or at much reduced speed during dark (adding eight hours to total passage time).
  • Allow for arrival in Nuuk during working hours.
  • Departure at first light in Labrador, 0430 local time underway.
  • Elapsed time of 78 hours at an average speed of ten knots while underway (allows for adverse current on Labrador side and going a bit slower to conserve fuel).
  • Winds as light as possible, but hopefully no higher than 18 knots and preferably less.
  • Visibility of half mile minimum.
  • Maximum visibility and minimum winds on first and last days as we are in coastal influence where highest ice density exists.

Rick’s comments over the past few days are below and will give you a feel for just how fluid the situation remains.

July 4th:

  • My review of the weather situation does not indicate to me that leaving tomorrow or Saturday is a good idea.
  • The broad area of low pressure over NE Canada shown by GFS and NGPS, confirmed by satellite imagery and QSCAT winds, have created SEerly winds over your route. SE winds shifts to SWerly tomorrow (July4th) in advance of a weakening cold front slowly moving eastward. A secondary low is shown to form on the front south of Greenland on July5th and maintains the southerly winds. Southerly winds over the Labrador Sea could create extensive areas of reduced visibility in fog. A third low from central Canada moves rapidly eastward into the Labrador Sea. NGPS shows gale SEerly winds in the central Labrador Sea and along the west coast of Greenland on Jul8th. This is certainly believable given the climatology. GFS has low moving eastward but further south, also believable.
  • After the third low, high pressure may ridge in from the west over the western Labrador Sea on July 10 or 11th. This would be a potential departing date.
  • Also a review of the current Canadian daily ice berg analysis from 3 July shows numerous ice bergs per square degree anything north of 53N. So, I would head due east until the ice berg limit at 050W, then turn north. URL: http://ice-glaces.ec.gc.ca/app/WsvPrdCanQry.cfm?CanID=11091&Lang=eng
  • Let me know what you think.

Second July 4th e-mail:

  • I could go with light Serly winds over Labrador current, because the fog will be reduced and your visibility requirement in only 1/2nm.
  • According to today’s Canadian ice analysis, ice hazards extend to about 049 15W from where you are. Ice hazards include ice bergs, growlers and bergy bits.
  • I would recommend a due east course along 53N to about 049 15W to minimize time in ice hazard area. Then proceed north to Nuuk.
  • Weather: GFS and NGPS still in disagreement regarding the strength of SWerly winds. NGPS calls for SW winds 15-20kts if departing tomorrow 0400LT (0800Z). This is reasonable considering the presence of the anchor low and secondary lows discussed yesterday. I recall your constraints are 18kts. For these reasons, suggest departing after July 9th, as the least risky option.
  • If more risk can be tolerated, then an earlier departure possibly on July 7th may be possible.
  • According to GFS if departing tomorrow, then your track would in the path of a low moving eastward from NE Canada. So would not recommend departing tomorrow or on the 6th.

July 5th:

  • Thank you for your kind remarks in your last note. After making a judgment on weather data, I put myself in my client’s position and ask myself if it was me going on the trip what would I do? That approach puts a more conservative look at things and has been successful in the past. If the client other options, I describe the associated risks so an informed decision can be made.
  • Today’s GFS/NGPS model guidance shows agreement out to 08Jul0000Z and beyond. Do you see the gale force low pushing off NE Canada making for 35kt winds in the Labrador Sea?
  • Models begin to digress afterwards. On the 9th, GFS dissipates a weak low and builds a ridge and a weaker Nerly 5-12kt pressure gradient over your track. Near perfect conditions for a 10Jul0800Z departure.
  • However, NGPS maintains the broad area low with a strengthening trend presenting a totally different picture than GFS and a "no-go" scenario on 9-10July time frame
  • We will need to monitor and see who wins out.

Wind Horse and crew are ready to depart. But it looks like we will be enjoying Labrador for at least another few days, and perhaps longer. This waiting for the right weather window is a new experience, but dealing with the small pieces of ice makes it a necessity. In the meantime, we have lots of photos to work on (some of which we will post when we get an Internet connection), books to read, and of course, new territory to explore in Labrador.


Posted by Steve Dashew  (July 6, 2008)




One Response to “The Waiting Game”

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