Facebook

Login

Support Sailonline

If you haven't already - join the SAILONLINE YACHT CLUB!

Please also consider making a donation - all amounts are greatly appreciated!

Board » Technical Discussion » Gribs

Posted by
bonknhoot


Users avatar

Posts
108
Registered at
2013-08-06 21:35:15
2019-03-06 07:45:49 - Gribs
When the Sardinia Cup opened yesterday, some racers noted that the wrf gribs outside the racing area and out to the weather system looked odd, and they do, and they always have done. As we do not sail there and the software that modulates the synoptic forecasts to generate local so-called 'meso' effects has to do a lot of 'crunching', the wrf gribs that are fed into SOL only cover the racing area. The rest of the weather that you see on SOL or that you download from SOL via brainaid or AGL is generated by the SOL bilinear interpolator. Since between the race area boundary and the weather boundary there is only one piece of data available for interpolation, that being the data at the race area boundary, the result of this interpolation is constant wind out to the weather system boundary and this looks odd especially if the weather system boundary is a long way 'out'. Those of you mathematically-minded may well wonder why does the weather not reduce linearly to 0 at the edge, then. Well, because that's not how the algorithm is written.
Some of you may also wonder why we show weather out beyond the race area at all. The reason for that is that the predictor line(s) pointing out from your bow will go haywire if it/they run(s) out of wind in less than six hours ahead. So we have to have wind six hours ahead at your boat's Vmax at right angles out from the boundary.
As said, it has always been thus, from the very first time we used wrf for the Boston to Newport and then for such iconic SOL perennials like Pacific North West and The Vineyard and all our Sprints including those in 60kn DN's requiring gribs extending across vast areas of frozen forests, prairies, tundras and the like.
Clipping along

Please login to post a reply.

Races

Next Race: 00d 00h 00m

Current Races:

Bight of Bonny TIMED Race 2026

Welcome to the first TIMED race of 2026! Our race finds us in the Gulf of Guinea and the Bight of Bonny. Starting in Douala, Cameroon the 170 nm course takes us around the island of Bioko with its Caldera and tropical rainforests finishing in Calabar, Nigeria. The boat for this race is the sporty Farr 30. This is a TIMEDrace so you may RE-REGISTER HEREto try again after finishing a run. You will have 13 days and 11 hours to test your skill and decision making after the race opens.
Race #2004
INFOby brainaid.de
Farr 38 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ1 - TRCH - SYC
RACE CLOSE: Saturday,
24 January at 23:00 UTC
Race starts: Jan 11th 12:00 Registration Open!
▶ Flash
GO TO RACE

Natuna Sea Race 2026


At 4.0N 108.2E lies the island of Natuna Besar, Great Natuna, surrounded by at least 154 islands, of which 127 uninhabited, Indonesia’s Natuna Regency, and all around this archipelago, the Natuna Sea, bordered by Borneo to the east, the Java Sea to the south, and the Malay peninsula to the west, and extending north to cross a disputed international border with China into the South China Sea. And it’s a border that matters, there’s gas here! But why worry, let’s race – 2050nm in our goo’ol’ Open 60s in between the production platforms, prowling destroyers and submarines.
Race #1997
INFOby brainaid.de
Open 60 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
Race starts: Jan 06th 17:00 Registration Closed
▶ Flash
GO TO RACE

Cape Town to Rio 2026

Welcome to South Africa and RCYC's classic transatlantic Cape2Rio Race from Cape Town, South Africa, to Rio de Janeiro, Brazil. First run in 1971, this run is buddied with the IRL, Cape2Rio 2025 arranged by the Royal Cape Yacht Club with the cooperation of the
Iate Clube do Rio de Janeiro Despite this being announced the 2025 race (starting dec. 27) it is the 2026 SOL championship kickoff. This virtual version, will be raced once again in Mark Mills' 74ft speedster, the stunning C2R74.
Race #1996 INFO
by brainaid.de
C2R74 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
OCQ1 - OCCH - SUPBUD - SYC
Race starts: Dec 27th 12:00 Registration Closed

▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member KaSToR
  2. Sailonline Yacht Club Member WRmirekd
  3. Sailonline Yacht Club Member CriticalHippo
  4. Sailonline Yacht Club Member rafa
  5. Sailonline Yacht Club Member vida
  6. Sailonline Yacht Club Member bonknhoot
  7. Sailonline Yacht Club Member Sax747
  8. Sailonline Yacht Club Member rumskib
  9. Sailonline Yacht Club Member CollegeFund
  10. Sailonline Yacht Club Member Panpyc

View full list

Series

Mobile Client

SYC members have the benefit of access to our mobile/lightweight web client!

The mobile client