NOAAWinds - Revision history

Mclean: /* Getting long-range forecasts */

2014-11-22T11:44:30Z

‎Getting long-range forecasts

Mclean: /* How VRTool applies NOAA GFS gribs */

2014-11-01T06:43:07Z

‎How VRTool applies NOAA GFS gribs

Mclean: /* Getting long-range forecasts */

2014-11-01T06:38:13Z

‎Getting long-range forecasts

Mclean: /* Game wind downloads */

2014-11-01T06:33:41Z

‎Game wind downloads

Mclean: /* How VRTool applies NOAA GFS gribs */

2014-11-01T06:33:21Z

‎How VRTool applies NOAA GFS gribs

Mclean: /* How VRTool applies NOAA winds */

2014-11-01T06:09:11Z

‎How VRTool applies NOAA winds

Mclean: /* How VRTool downloads NOAA winds */

2014-11-01T06:08:04Z

‎How VRTool downloads NOAA winds

Mclean: /* Getting long-range forecasts */

2014-11-01T04:03:57Z

‎Getting long-range forecasts

Mclean: /* NOAA GFS weather forecasts */

2014-10-30T07:39:10Z

‎NOAA GFS weather forecasts

Mclean: /* How Virtual Regatta games use NOAA GFS gribs */

2014-10-30T07:28:14Z

‎How Virtual Regatta games use NOAA GFS gribs

← Older revision		Revision as of 11:44, 22 November 2014
Line 67:		Line 67:
	For example between 04:00 and 10:00 UTC (the yellow part of the column) VRTool probes the '''t00z''' GFS run, and chooses the '''f06''', '''f18''', '''f30''', '''f42''' ..... gribs from that sequence. Beyond '''f192''' VRTool will '''not''' find matching gribs unless it is selecting time-stamps that are multiples of 12.		For example between 04:00 and 10:00 UTC (the yellow part of the column) VRTool probes the '''t00z''' GFS run, and chooses the '''f06''', '''f18''', '''f30''', '''f42''' ..... gribs from that sequence. Beyond '''f192''' VRTool will '''not''' find matching gribs unless it is selecting time-stamps that are multiples of 12.

−	This means that forecasts out to '''f384''' can ~~only~~ be imported only when the '''t00z''' or '''t12z''' GFS run is current (during the green and blue parts of the table), and only after the GFS run is fully completed.	+	This means that forecasts out to '''f384''' can be imported only when the '''t00z''' or '''t12z''' GFS run is current (during the green and blue parts of the table), and only after the GFS run is fully completed.

@@ Line 37: / Line 37: @@
 ==How VRTool applies NOAA GFS gribs==
-VRTool always downloads the latest available gribs '''except''' that it "hangs on" to the ''f06'' gribs for 12 hours so its current weather matches the game's. (This is clearly not right for "real life" modelling and navigation, but as of version 2.31 there is no way to change this.)
+VRTool always downloads the latest available gribs '''except''' that it "hangs on" to the ''t00z.f06'' and ''t12z.f06'' gribs for 12 hours so its current weather matches the game's. (This is clearly not right for "real life" modelling and navigation, but as of version 2.31 there is no way to change this.)
 The following table shows the relationship between the NOAA production cycle and VRTool's grib management. The middle column shows the timing sequence for the 2014/2015 VVOR - this is subject to change by the game organisers.<br><br>

@@ Line 53: / Line 53: @@
 ==Getting long-range forecasts==
-The NOAA GFS produces '''long-range''' Gribs out to 16 days in the future. VRTool can import these, but only during the following hours:
+The NOAA GFS produces '''long-range''' gribs out to 16 days in the future. VRTool can import these, but only during the following hours:
 *10:45-16:00 UTC
 *22:45-04:00 UTC
-The reason for this is as follows: Each 6-hourly GFS run predicts wind at '''3-hour''' forecast intervals up to 192h and then at '''12-hour''' forecast intervals up to 384h. So each run produces a sequence of Grib files with the following time-stamps:
+The reason for this is as follows: Each 6-hourly GFS run predicts wind at '''3-hour''' forecast intervals up to 192h and then at '''12-hour''' forecast intervals up to 384h. So each run produces a sequence of grib files with the following time-stamps:
 <tt>&nbsp;f00, f03, f06, f09 ...... f189, f192, f204, f216 ...... f360, f372, f384</tt><br>
 <tt>|<-------3-hour intervals--------->|<---------12-hour intervals--------->|</tt>
-When VRTool is set to import weather at '''12-hour''' resolution it automatically chooses the appropriate Gribs from the current GFS run. If you look carefully at the table in the preceding section, in the third column you can see that the time-stamps that VRTool selects change depending on which GFS run is being used.
+When VRTool is set to import weather at '''12-hour''' resolution it automatically chooses the appropriate gribs from the current GFS run. If you look carefully at the table in the preceding section, in the third column you can see that the time-stamps that VRTool selects change depending on which GFS run is being used.
-For example between 0400Z and 1000Z (the yellow part of the column) VRTool uses the '''t00z''' GFS run, and chooses the '''f06''', '''f18''', '''f30''', '''f42''' ..... gribs from that sequence. Beyond '''f192''' VRTool will '''not''' find matching Gribs unless it is selecting time-stamps that are multiples of 12.
+For example between 04:00 and 10:00 UTC (the yellow part of the column) VRTool probes the '''t00z''' GFS run, and chooses the '''f06''', '''f18''', '''f30''', '''f42''' ..... gribs from that sequence. Beyond '''f192''' VRTool will '''not''' find matching gribs unless it is selecting time-stamps that are multiples of 12.
 This means that forecasts out to '''f384''' can only be imported only when the '''t00z''' or '''t12z''' GFS run is current (during the green and blue parts of the table), and only after the GFS run is fully completed.

← Older revision		Revision as of 06:33, 1 November 2014
Line 34:		Line 34:

	The current weather in the game uses the ''f06'' grib; the +12h forecast uses the ''f18'' grib and so on.		The current weather in the game uses the ''f06'' grib; the +12h forecast uses the ''f18'' grib and so on.
−
−	~~== Game wind downloads ==~~
−	~~VRTool game wind forecasts are gathered from different files from GFS forecasts.~~
−	~~Current wind (forecast 00) is the same as the game's ( file 06 from NOAA folders 00Z and 12Z ).~~
−	~~Future winds (12,24,36 etc) are taken from the latest files available at the time of the download.~~
−
−	~~Note that VRTool future winds (12,24,etc) are different from game's most of the time, because they are taken from newer predictions (probably better).~~

	==How VRTool applies NOAA GFS gribs==		==How VRTool applies NOAA GFS gribs==

@@ Line 43: / Line 43: @@
 ==How VRTool applies NOAA GFS gribs==
 [[file:NOAAWindsSchedule.gif]]
@@ Line 51: / Line 56: @@
 |}
-If you do a further download when the current weather in your game updates you will not get anything new. VRTool already has the gribs from the the earlier download, and the routing does not change. All that happens is the annotations on the tracks adjust forward by 12 hours.
+If you do a further download when the current weather in your game updates you will not get anything new. VRTool already has the gribs from the earlier download and the routing doesn't change. All that happens is the annotations on the tracks adjust forward by 12 hours.
 ==Getting long-range forecasts==

@@ Line 42: / Line 42: @@
 Note that VRTool future winds (12,24,etc) are different from game's most of the time, because they are taken from newer predictions (probably better).
-==How VRTool applies NOAA winds==
+==How VRTool applies NOAA GFS gribs==
 [[file:NOAAWindsSchedule.gif]]

@@ Line 42: / Line 42: @@
 Note that VRTool future winds (12,24,etc) are different from game's most of the time, because they are taken from newer predictions (probably better).
-==How VRTool downloads NOAA winds==
+==How VRTool applies NOAA winds==
 [[file:NOAAWindsSchedule.gif]]
-If you are using weather routing or the track designer, you should update
+To ensure that VRTool has the most recent predictions you should download NOAA gribs '''right after''' the following times: '''04:00''', '''10:00''', '''16:00''' and '''22:00 UTC''', and recalculate your route. This will generally give you the forecasts an hour or more before they appear in the game.
 {|class="wikitable"
-|Tip: The 2 hour advance in relation to game wind shift can be even larger. NOAA file publication is gradual. Files start to be released 30 minutes before 4Z and 16Z, and the folder is completed (up to 384h) about one hour later. So one could advance the computer clock  some 30 minutes and get a preview of the first few forecasts even earlier.
+|'''Tip:''' ''VRTool's download module switches to the new GFS cycle at the UTC times stated above. The early gribs in the cycle are available some time before this. You can make VRTool switch to the new cycle earlier than it should by tweaking the '''time zone''' setting in the NOAA download module. If you tweak it too far the download probe won't find anything.''
 |}
 ==Getting long-range forecasts==

@@ Line 19: / Line 19: @@
     t12z   15:30   16:30 UTC
     t18z   21:30   22:30 UTC
 == How Virtual Regatta games apply NOAA GFS gribs ==

@@ Line 20: / Line 20: @@
     t18z   21:30   22:30 UTC
-== How Virtual Regatta games use NOAA GFS gribs ==
+== How Virtual Regatta games apply NOAA GFS gribs ==
 [[File:VRLogo.gif|left]] Virtual Regatta Games use gribs from only the ''t00z'' and ''t12z'' GFS cycles.