Sailonline.org - Online Sailing

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!

Tweets by @sailonline

Board » Technical Discussion » The Weather Research & Forecasting Model (WRF)

Page: 1 2 Next

Posted by ita10267 Posts 88 Registered at 2008-12-29 10:33:09	2015-02-09 08:28:44 - The Weather Research & Forecasting Model (WRF)
	We are proudly introducing the WRF Model as a new source of weather forecast data (GRIBs). WRF is recognized throughout the scientific community as the most accurate and reliable weather forecast model. An extensive (and technical) description of WRF can be found at: http://www2.mmm.ucar.edu/wrf/users/model.html The scope of this post, without entering into too much technical details, is to inform the SOL community about the features that this model can introduce and how we can benefit from it. In SOL we historically use the GFS weather model. According to its definition the GFS model is basically one “of the predominant synoptic scale medium-range models” in general use. Therefore it is good (within its accuracy which is around 30km with the resolution we are currently using) if wind is dictated by pressure/temperature fields. This means that, in shorter races, we rely on a small number of grid points and, in between them, we use interpolation. The result is a smooth wind field that is hardly able to follow coastlines. Of course we miss all the finer features that come within this scale, like funnelling, day/night breeze, swirls etc. We therefore decided to propose a trial of the WRF model, which is a local weather forecast that takes into account a number of small scale (accuracy in the 10m range can be reached) factors neglected in the GFS model. This is not an exhaustive list but a few of these factors are: - Landmass elevation profile - Urbanization - green fraction - soil composition (as sand heats differently from clay, concrete etc etc) - ground heating - sea heating So, many new local effects can be visible by SOL users. Of course, for those who are not aware about basic meteorology, there will be no difference in sailing with the old GFS model compared to the new one other than a more “realistic” feeling and less smoothed appearance of the wind field. The experienced sailor, on the other hand, will recognize the patterns he is usually able to see IRL. So, overall, we believe that the realism of SOL can be improved and increased by the new wx source. We have decided to test drive the new model on a classic run between Boston and Newport. For this purpose a 0.05deg spaced grid will be used. This is 10X more accurate than the most accurate GFS grid we have ever used. As a drawback, given the additional computational time and with the purpose of keeping update times consistent with the GFS model, a shorter maximum time window of only 2.5 days is available for the weather forecast as seen when moving the slider at the bottom of the client. Please take your time to explore the new wind data and post your feedback here in this thread.
Posted by Jan van der Puil Posts 92 Registered at 2013-08-06 21:35:15	2015-02-09 10:47:52 - Re: The Weather Research & Forecasting Model (WRF)
	brilliant! like!! Clipping along
Posted by JB Posts 305 Registered at 2013-03-07 08:54:34	2015-02-09 16:20:21 - Re: The Weather Research & Forecasting Model (WRF)
	Viva Andrea. Absolutely fabulous! Sail Fair.
Posted by Vince Nel (WW) Posts 101 Registered at 2011-11-05 09:30:13	2015-02-09 16:39:02 - Re: The Weather Research & Forecasting Model (WRF)
	Smart stuff. Nice. Thanks Andrea I like to talk a lot... sometimes I even make sense, mostly not...
Posted by RainbowChaser Posts 2655 Registered at 2009-06-14 09:44:50	2015-02-09 16:54:48 - Re: The Weather Research & Forecasting Model (WRF)
	And here's a quick pic to show you what the difference(s) are and.. how to set them - this pic shows how to chance the arrows, but with this new model the contour-settings will also be worth playing with: --- Last Edited by RainbowChaser at 2015-02-09 18:44:13 --- Attachments HIRES_Options_feb15_THUMB.png (5.3 KB) HIRES_Options_feb15.png (100.4 KB)
Posted by A2 Posts 347 Registered at 2009-10-26 00:39:42	2015-02-09 22:20:59 - Re: The Weather Research & Forecasting Model (WRF)
	Typically with Our normal resolution Wx grids are organized by every half degree of Lon/Lat & High Def by every quarter degree. With this new model, which sounds even better, will the Wx Grid quadrants be even smaller as well ? None so blind
Posted by hmm Posts 118 Registered at 2011-11-03 13:35:22	2015-02-09 22:35:47 - Re: The Weather Research & Forecasting Model (WRF)
	The Boston-Newport HI-RES test uses 0.05 degree grid. We of course need finer resolution for showing the detail.
Posted by A2 Posts 347 Registered at 2009-10-26 00:39:42	2015-02-09 22:58:01 - Re: The Weather Research & Forecasting Model (WRF)
	Well if we can resolve the new model so that our translation displays quadrant boundaries per every 1/8th degree then that would be most welcome. Also: My understanding is that the NOAA Wx is extrapolated from a 3 hour time frame. So what is the time resolution of the new model prior to our adaptation ? --- Last Edited by A2 at 2015-02-09 23:12:24 --- None so blind
Posted by ita10267 Posts 88 Registered at 2008-12-29 10:33:09	2015-02-10 07:39:06 - Re: The Weather Research & Forecasting Model (WRF)
	We have also higher time resolution with WRF. GRIB frames are spaced 1hr instead of 3hrs. This can help with faster gradients. @A2: I don't really get your point regarding quadrants. Can you explain? --- Last Edited by ita10267 at 2015-02-10 07:41:17 ---
Posted by A2 Posts 347 Registered at 2009-10-26 00:39:42	2015-02-10 14:34:20 - Re: The Weather Research & Forecasting Model (WRF)
	I really do appreciate this opportunity to have these types of discussions. First let me explain that I have little if any real sailing experience and lack the usual vocabulary that would seem natural to those that do. Also I do not employ any routing software to analyze in greater detail weather data as a whole. Let me be clear and state here & now that I have no complaint for those that incorporate such methods as that was the original purpose for the inception of this virtual sailing venue. So over the time I have spent here using just the information available in the browser client and the process of careful observation along with my attempt to visualize how to plan my navigational strategy I have identified rectangular areas that I call "quadrants" bounded by, most often, half degrees of lon/lat depending on the Wx resolution. These boundaries are where the isotachs have their pointy edges and if you follow either a 270-90 horizontal or 360-180 vertical line that the wind speed will exhibit its maximal or minimal transitions. --- Last Edited by A2 at 2015-02-10 14:40:31 --- None so blind

Page: 1 2 Next

Please login to post a reply.

Races

Next Race: 00d 00h 00m

Current Races:

Auckland to Fiji 2023
Welcome to Auckland and, for the fifth time in Sailonline's history, an epic race to the Melanesian island of Fiji, some 1144nm away. The iconic Steinlager 2 has traditionally been our boat of choice for this event, including in 2020, the last time we raced the course – alone, unaccompanied by a real fleet as it had been #COVID19 quarantined. Alas, this year we will again be racing unaccompanied as low entry numbers has seen the real race cancelled. Hopefully, though, some of the real sailors from the Royal Akarana YC, hosts of the real event, will be joining us online to pit their skills against ours in the ever-changing forecast winds.
Race #1675
INFO by brainaid.de
Steinlager 2 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
SYC
Race starts: Jun 03rd 01:00 Registration Open!

▶ Flash

GO TO RACE

Susan Hood Trophy Race 2023

Lake Ontario Offshore Racing (LOOR) welcomes racers to the third virtual Susan Hood Trophy race. This is a 75nm weekender on western Lake Ontario starting and finishing at the Port Credit Yacht Club (PCYC) via Niagara and Burlington, and is one of two that will count towards a special Sailonline's LOOR Series medals. As our Beneteau First 36.7 managed the course so well in previous years, we shall race her again!
Race #1690
INFOby brainaid.de
First 36.7 PARTICULARS
NAM_AWIP WX Updates:
0245 / 0845 / 1445 / 2045
Ranking: SYC - LOOR
Race starts: Jun 03rd 00:00 Registration Open!

▶ Flash

GO TO RACE

SoCal 300 2023

Here, once again, is your chance to participate virtually in a second race of the California Race Week calendar, SDYC's challenging 243nm (as the seagull flies) SoCal 300 from Santa Barbara to San Diego. With a broad range of boats entered in the real race, virtual SOLers will have to dig deep to remain competitive in our trusty Santa Cruz 52s.
Race #1674
INFO by brainaid.de
Santa Cruz 52 PARTICULARS
NAM_AWIP WX Updates:
0245 / 0845 / 1445 / 2045
Ranking: SYC
Race starts: Jun 01st 20:00 Registration Open!

▶ Flash

GO TO RACE

Cape Town to Auckland 2023
Welcome to this second RTW race 2023. It's also the June edition of this year's ocean race championship. The course is slightly different from the one sailed in 2020, which then also was part of the RTW series.
This time we will race in the IMOCA 60 foil, as in all RTW races this year. That should guarantee the fun in the South Seas in a truly tough race.
PRIZE: SMPF
Race# 1685
INFO from brainaid.de
IMOCA 60 foil Particulars
WX updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ2 - OCCH - RTW - SUPSOL - SYC
Race starts: Jun 01st 09:00 Registration Open!

▶ Flash

GO TO RACE

CA 500 2023

To celebrate the 50th anniversary of the TransPac Ocean Race in 2019, the organisers of the California Race Week introduced a new longer distance event for line-honours machines. Popular with the largest maxi trimarans, this CA 500, 500nm from San Francisco to San Diego, repeats in 2023, and if you don’t own a maxi trimaran, Sailonline are delighted to have the honour to, for the first time, make their virtual version available to you for a quick ethereal dash down America’s west coast.
Race #1687
INFO by brainaid.de
Maxi Tri PARTICULARS
NAM_AWIP WX Updates:
0245 / 0845 / 1445 / 2045
Ranking: SYC
RACE CLOSE: Saturday,
June 3 at 2300 UTC.
Race starts: May 26th 18:00 Registration Open!

▶ Flash

GO TO RACE

Lisbon to Cape Town 2023
Our second OCC race in Q2 is also our first race of a special
6-race RTW series, in IMOCA 60 Foilers, from the board of ita10267. Long bluewater legs, with the shores of the World's continents the only restriction on where you may sail, starting with a 5000nm leg from Lisbon to Cape Town. Enjoy!
PRIZE: SMPF
Race #1683
INFOby brainaid.de
IMOCA 60 foil Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ2 - OCCH - RTW - SUPSOL - SYC
RACE CLOSE: Thursday,
June 1 at 2300 UTC.
Race starts: May 03rd 09:00 Registration Closed

▶ Flash

GO TO RACE

Go to race archive

SYC Ranking

View full list

Series

Mobile Client

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

The mobile client