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
109
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:

Roma per Tutti 2026


Sailonline are honoured and delighted to have been asked to partner an online first Roma per Tutti yacht race with organizing yacht club, Circolo Nautico Riva di Traiano . In real life, this will be the 33rd edition of this 540nm offshore race from Rome’s Riva di Traiano to the Aeolian Islands and back. Online, the race will not only be our first partnership with CN Riva di Traiano, but also the second race of our Magical Mediterranean series. A number of Mini 6.50s have been entered for the 33rd edition of the Roma per Tutti; so our own vintage Mini is also our virtual yacht of choice for this one.
Race #2019
INFOby brainaid.de
Mini 6.50 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: MED - SUPBUD - SYC
Race starts: Apr 11th 10:00 Registration Open!
▶ Flash
GO TO RACE

Rommel by Balloon 2026 - Through the Sahara


Generalfeldmarschall Johannes Erwin Eugen Rommel may have been that chivalrous, gallant tank commander of legend, led astray by the Prussian military traditions of loyalty and chain of command, but one thing he wasn’t, was mad. So, let’s do it anyway – not stick to the coast and the battle for logistical superiority – but depart the oases of Siwa south west into the desert for Agadez and its uranium. And let’s go by balloon, it’s only 2500km (1250nm)!
Race #1973
INFOby brainaid.de
SOL Balloon PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: BOL - SYC
Race starts: Apr 07th 13:00 Registration Open!
▶ Flash
GO TO RACE

Falklands to Tasmania 2026

Welcome to yet another all-new route. This next race is part of our Ocean Championship as well as the ROW series. Falklands to Tasmania, is like last year's island to island. It’s one of the longer ones 6400nm, more than half way around the world (and the Antarctica). It starts the 2026 OCQ2, and will be sailed in our Steinlager 2, contrary to prior notice.
Race #2021
INFO by brainaid.de
Steinlager 2 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ2 - ROW - OCCH - SYC
Race starts: Apr 06th 11:00 Registration Open!
▶ 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 rafa
  4. Sailonline Yacht Club Member rumskib
  5. Sailonline Yacht Club Member CriticalHippo
  6. Sailonline Yacht Club Member CollegeFund
  7. Sailonline Yacht Club Member Panpyc
  8. Sailonline Yacht Club Member Sax747
  9. Sailonline Yacht Club Member sassy63
  10. Sailonline Yacht Club Member vida

View full list

Series

Mobile Client

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

The mobile client