OpusFSI Flight Simulator Interface for and

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OpusFSI Flight Simulator Interface for Prepar3D

The OpusFSI Live Weather Engine

4 Jan 2022

Opus Software Limited

Email: opusfsi@opussoftware.co.uk  Website: www.opussoftware.co.uk/opusfsi.htm  


Overview... 3

Live Weather Features. 3

Sky and Cloud Textures. 4

Slow and Low Flyer Configuration.. 4

High Flyer Configuration.. 4

Configuration.. 5

Dynamic Live Weather 6

Update Weather 6

Flight Plan Options 6

Weather Download Options. 7

Smoothing and Stabilisation. 8  

General User Preferences

Recommended Settings and Practice

Historic Weather Data

Weather Data Import (current and historic)  

METAR Import

World Weather Themes.

Weather Relocation.  

Live Weather Overview and Locator 

Building Live Weather.

Weather Data Collection..

Weather Data Smoothing..

Mist and Fog Layers.

Low Overcast Effect

Cloud Positions and Textures.

Cloud Icing.

Cirrus Cloud Layers.

Winds and Temperatures Aloft

Wind Shear

METAR Station List Corrections and Additions

Turbulence and Dynamic Head Movement (DHM)

OpusFSI Site Effects

Flight Planning Assistant Reports

Sim Weather Reports

Opus Weather Reports

Text Reports

Spy Messages. 19  

Live Weather Assistant Maps

Smaller Footprint Weather Maps

Client Side Weather Control


PMDG FMC Wind/Temp Data Request

FSUIPC Settings

Reporting Anomalies and Errors. 19

FAQ.. 19  




The Live Weather Engine is a standard feature within the OpusFSI Flight Simulator Interface for the Microsoft's Flight Simulator X and Lockheed Martin Prepar3D simulators.

The Live Weather Engine provides live weather updates on your OpusFSI system. The live weather data is acquired by either downloading the current METAR reports for all Met stations within your weather horizon or importing the METAR reports contained within a user specified import file. The weather engine's horizon covers an area of 1280km by 1280km centered on your aircraft's current position, this is the size of the detailed Dynamic Weather region created by the engine.

As you are probably aware the use of METAR data to update the weather in the simulator leaves a lot to be desired. To adjust the weather correctly using METAR updates you are forced to clear the current weather completely and either load a totally unrealistic globalised weather pattern, resulting in the same weather horizon to horizon and false ATC and ATIS reports, or reload the new METAR data very slowly one station at a time. This METAR update process is not only totally unrealistic, but can result in a great deal of screen flicker while the simulator slowly loads the new METARs. There are also problems with METAR voids, METAR morphing, and inconsistent weather synchronization across networked systems using METAR updates. These problems are inherent within the Prepar3D simulator. On the other hand, our Dynamic Weather loads instantly into the simulator with no screen flicker, no disturbance to the flight, no weather morphing, and no inconsistencies with ATC or ATIS.

The Live Weather Engine has set a new standard for weather updates within the simulator community. OpusFSI provides the most efficient and accurate weather updates for Lockheed Martin's Prepar3D simulator.


Live Weather Features


Sky and Cloud Textures

The Live Weather Engine does not include any sky and cloud textures. For optimum effect we strongly recommend you install sky and cloud textures from packages such as Flight Environment X (payware) or HDEv2 (freeware) for clouds with the sky upgraded by Danny Glover, and use the OpusFSI Live Weather Engine for the actual weather updates.

We would strongly recommend using lower resolution 1024 cloud textures and also not using HD cloud textures, this will be beneficial in terms of frame rates as well as looking more realistic and less harsh.  


Slow and Low Flyer Configuration

If you cruise below FL200 then just set your Destination and Max Cruise Altitude.


High Flyer Configuration

If you cruise above FL200 then set your Destination and Max Cruise Altitude. If your system has wind shifts enable the Sim Friendly GRIB Wind Targets option in the Weather Download dialog, this option gives you winds very close if not the same as the true forecast, especially if you have specified your Cruise Altitude.



You will need to set your sim to run in windowed mode (i.e. press ALT+ENTER, or turn off full screen mode in the P3D View menu) in order to display the FSI SERVER form. The server and all client displays will be paused whilst the dialog is active.

The Live Weather Engine is enabled via the OpusFSI server program's Configuration dialog, accessed via the Configure button on the FSI SERVER's main form or via the Add-ons menu option.


To enable, tick the Enable Live Weather Engine checkbox within the Configuration dialog.

Ensure you have disabled all other weather injection from P3D, third party engines, VATSIM/IVAO etc.

You can open the Weather dialog, load a flight plan, force a reload/update/refresh of the Live Weather, temporarily disable/enable Live Weather updates, or enable/disable/save World Weather themes using the OpusFSI Live Weather options within the simulator's Add-on menu.


The Live Weather update parameters and import options are specified within the Weather dialog, accessed via the Weather button on the FSI SERVER's main form.

Dynamic Live Weather  

If the Disable Weather Update on Startup option is enabled the LWE will remain dormant until you force a weather update either via,

·         automatically activating a flight plan (Flight Plan Options, Auto Load Newest Flight Plan For Departure) or manually loading or activating a flight plan,

·         the Add-ons menu (OpusFSI Weather options),

·         the Full Weather Reload button in the Weather dialog

·         a Shortcut Control (OpusFSI_v6_ User Guide).

This option allows you to enter the flight details and adjust the weather settings prior to generating and updating the weather at the start of your flight.

You may enter (or paste) your flight plan, or a list of ICAO, nav aids and general waypoint codes into the Flight Plan edit box. Your flight plan destination ICAO will be automatically copied to the Destination ICAO field. Various options are provided to load, edit and save flight plans in the Flight Plan Options.

If you haven't entered a Flight Plan or Station List then configure a Destination ICAO Code and up to four alternate airfield designations. Always specify your destination ICAO, this is very important in preventing wind shifts. The specified destination and alternate airfield weather is updated automatically without the need to constantly download new METAR reports. These automatic updates ensure compliance with the current downloaded METAR reports at these locations. You can change the ICAO codes in flight. It is recommended you update the weather manually (via the dialog or add-on menu) when you change the ICAO codes, either before a flight or whilst airbourne.

Weather Report windows provide accurate weather reports for the specified destination and alternate airfields. These reports can be used in place of ATIS and are accurate out about 640km (400 miles or 345nm).  

The Max Cruise Altitude setting in the weather dialog allows you to specify a reference cruise altitude (max 65000 ft). You can enter a three digit flight level, or FLnnn format (e.g. FL230), or an altitude. All altitudes less than 1000 feet are interpreted as an implied flight level. For the Sim Friendly GRIB wind adjustment, any cruise altitude less than 20000 feet will reference the forecasted tropopause height.

Update Sites When Distant will update the weather at the specified Destination and all specified Alternate sites using the Selective Update methods. These updates will occur whenever a theme is updated and the sites are on the current weather map but currently lie outside the area covered by the Dynamic Weather Theme. This option allows accurate (Actual) Destination and Alternates weather when up to 400 miles (about 640km) away!

Export World Weather when enabled will save the world-wide GRIB data in a single 8.45Mb OpusGribExport.dat data file in the \OpusFSI_v6\Weather folder and the METAR data in the OpusMetarExport.txt file. These files are intended for use by third-party flight planning packages. The supplied OpusFSI_v6_Weather_Export.pdf document in the \OpusFSI\Weather folder provides details of the both the exported GRIB data and METAR text file formats. This document can also be downloaded from our Downloads page via the hyperlink at the bottom-right of the page.

If you want historic data then set your sim time to the required time within the last 24 hours and tick the Historic Weather checkbox.

Refer to the section below for Weather Relocation.

Refer to the section below for Weather Download Options.

Refer to the section below for Smoothing and Stabilisation.

Refer to the section below for General User Preferences.

Refer to the section below for METAR Import.

The Global METAR Conditions checkbox and combo box option in the Weather dialog is used to select and specify global METAR conditions for use in the sim. The global conditions are specified in standard METAR form excluding the ICAO and Day/Time code at the start. In other words excluding the "ICAO DDHHMMZ" phrase at the start. For example, the string "27004KT 2000 SCT042 04/01 Q1018" would specify a surface wind of 270 at 4 knots, visibility of 2000 metres, scattered cloud at 4200 feet, temperature 4, dew point 1, and a QNH of 1018mb. The dropdown list stores a history of your METAR conditions.

Refer to the section below for World Weather Themes.

If you have set your Destination and Max Cruise Altitude then you can go ahead and fly without setting any further options in the Weather Download, Smoothing and Stabilisation, and General User Preferences dialogs, they are provided for you to tweak the settings manually if required.  


The Defaults button sets all recommended default options.

Reload, Update  and Refresh

The Full Weather Reload option performs a full update of the weather without any cloud/visibility smoothing (equivalent to the initial weather update or updates when on the ground).

The Update Current Weather option performs a full update with cloud/visibility smoothing (when it is enabled) and you are airborne.

The Refresh Current Weather option requests a weather regeneration or refresh using the current METAR and GRIB data with cloud/visibility smoothing (when it is enabled) and you are airborne. Iin other words it does not download new METAR or GRIB data.  

Reload - download new METAR or GRIB data, no smoothing

Update - download new METAR or GRIB data, with smoothing

Refresh - no download of data, with smoothing

All requested Weather Refreshes are performed at the next appropriate time as determined by the Live Weather Engine. The text in the Weather button on the FSI SERVER form is grayed out and changed to 'Updating' whilst the LWE is busy refreshing or downloading and updating the weather.

Flight Plan Options

The LWE will automatically import flight plans activated via the sim. In addition two options are included with this dialog, Auto Load Newest Flight Plan For Departure and List All Available Flight Plans For Departure. Flight plans may also be loaded via the sim’s Add-ons OpusFSI Live Weather menu option.  

If the PLN File Watcher on Import Folder option is enabled then the Live Weather engine will detect and process any changes to, or the creation of a new, PLN flight plan within the current Import PLN Flight Plan Folder. Any change to a PLN flight plan file (or the creation of a new PLN flight plan file) will be processed and trigger a Full Weather Reload. Disable the PLN File Watcher if you prefer to manually select and load a departure flight plan before flight.

The full file specification for all P3D activated (loaded) flight plans is displayed within the main Spy window of the OpusFSI SERVER program.

However if you wish to manually import, edit, or enter and process a flight plan then you can do it via this dialog.

Identifying your Navdata Source

The flight planning assistance software decodes the standard Navigraph Navdata Navaids and Waypoints text files for use in identifying all Nav aids and general waypoints within the your flight plan. 

First locate your Navdata folder. The standard <SIM>\Navigraph\Navdata\ path is the default location for these files but you may Browse to different folders on Prepar3D systems should they be located elsewhere (e.g. NavDataPro folder). The Navigraph Navdata supplied for the PMDG aircraft is in your <SIM>\PMDG\NAVDATA folder in the wpnavaid.txt and wpnavfix.txt Navigraph files. iFLY files are in the <SIM>\iFly\Navdata folder.

If you do not have any Navigraph files then a default version of the files (apart from SIDs and STARs) are installed into your OpusFSI_v6\Navdata folder. To update Navigraph files subscribe to Navigraph's FMS data service at www.navigraph.com.

You will know if OpusFSI has extracted the Nav data because the NAVAIDS.DAT and WAYPOINTS.DAT files will be created in the OpusFSI_v6 folder. The NavData is reloaded each time you change the folder location, or press the Reload or Process the Flight Plan buttons, or exit the dialog.

N.B. you only need to identify your Navdata folder once and it will be used for all aircraft types, you do not need to change the Navdata folder when selecting aircraft from different manufacturers. The same Navdata folder can be used for all sim types.

Entering a Flight Plan Manually

If you enter the flight plan manually then your flight plan should start and end with a station's ICAO code, i.e. in the form,

            <origin> <nav aids and waypoint fixes and airways> <destination>

e.g. EGCC 53.317167N2.318000W WAL33 TULIP LFST

Your departure and destination points are required in order for the software to identify the specific Nav aid or waypoint since many of them have shared names. So make sure you specify your origin and destination ICAO codes. The origin, destination and fixes can also be defined as Lat Lon fixes. 

The formats for Lat Lon fixes are as follows,  

<sign><lat>/<sign><lon>:<code> e.g. 12-34-56/-123-45-67 12°34'56"/-123°45'67" or 1234/-12345 or 1.23/-1.23:ABC1
<lat><N or S><lon> <E or W>:<code> e.g. 12-34-56N123-45-67W or 1234N12345W or 1.23N1.23W:ABC1
<N or S><lat><E or W><lon> :<code> e.g. N12-34-56W123-45-67 or N1234W12345 or N1.23W1.23:ABC1
<N or S><lat> <E or W><lon> :<code> e.g. N12-34-56 W123-45-67 or N1234 W12345 or N1.23 W1.23:ABC1


<sign> =  + (optional) to indicate North or East  
- to indicate South or West  
<lat> =  dd-mm-ss  
<lon> = ddd-mm-ss  
<code> =  optional ICAO code or station name
dd = degrees in 2 digits
ddd = degrees in 3 digits 
deg = degrees represented in decimal form e.g. 30 minutes would be 0.5 degrees  
mm =  minutes in 2 digits
ss  seconds represented in decimal form 


All LatLon fixes used to define either the point of departure or destination within flight plans are temporarily added to the OpusFSI station list with a pseudo name Xnnn, where 'nnn' ranges from 000 to 999. If the LatLon fix is within 2km of an existing station then that station is assumed to be identified.  


Saving and Loading a TXT Flight Plan

You can use the Save button to save your manually entered flight plan in a text file. These saved flight plans can be loaded in future flights using the Load button. All text flight plan files contain the cruise altitude and flight plan string on two separate lines. Text flight plan files are stored in the \OpusFSI_v6\Plans folder. The Import the Cruise Altitude checkbox option is used when loading text flight plans.

Importing a PLN Flight Plan

You can import any PLN formatted flight plan (with .PLN filename extension). The Import Flight Plan option will initialise its path to your My Documents folder ready for you to navigate to your actual Prepared3D v5 Files, or other folder name (for foreign language systems). Your PLN folder's location is remembered by the FPA software after you have selected the required .PLN filename. An Import the Cruise Altitude checkbox option is provided to enable or disable the importing of the cruise altitude from the flight plan.

All flight plans activated within the simulator are decoded and processed automatically. For this to happen the OpusFSI SERVER program must be running before the flight plan is loaded into the simulator.

The decoding of Lat/Lon coordinates in imported PLN flight plan files has been extended to accept delimited degrees (°), minutes (') and seconds (") coordinated values.

Processing a Flight Plan

If you have manually entered or edited a flight plan, or loaded a TXT flight plan then you need to process the flight plan. Click on the Process the Flight Plan button to decode the Flight Plan and display the result in the Identified Navigation Points box. The navigation aids and waypoints, where they exist, are displayed with their Lat/Lon coordinates, general type and two letter country codes. Where possible the specified label of any lat/lon waypoint fixes are shown. Airway fixes are displayed in green. Alternate Met stations are displayed in red. 

The software ignores all identifiers that are not listed as Nav aids and waypoints. Airways are recognised provided the entry point is specified, also if you have specified both entry and exit points in the flight plan (usually done) then the FP Assistant will replace the Airway with the list of points en route and provide weather information and upper winds/temps for each of those navigation points.

The nearest four Met stations within 128km (80 miles) of a navigation point are added to the download list. 

The Flight Plan Details editbox lists all identified navigation points extracted from your flight plan.

If you subsequently change your alternates then you will need to process the flight plan again.

Just remember to force a weather update to download the METARs. Until then there will be no METAR data since it hasn't been downloaded. After downloading, all the non-reporting Met stations are removed from the list.  

Exporting a PLN Flight Plan

The Export PLN Flight Plan option will save the current processed flight plan into a standard user specified P3D PLN file.

Auto Load Newest Flight Plan For Departure

When ticked the Auto Load Newest Flight Plan For Departure will instruct the OpusFSI Live Weather engine to search for all likely flight plans for your point of departure in the current specified Import/Export folder. It will then determine the newest (last updated) file and automatically import (load) the newest flight plan. This feature is only active when on the ground. After the flight plan has been loaded a Full Weather Reload is performed by the weather engine.

For a flight plan file to be recognised the departure point's ICAO code must appear within the filename and start within the first four characters. In other words you are allowed to have up to three characters preceding the ICAO code. The checks are not case sensitive.

For example, assuming the aircraft is on the ground at EGNX (East Midlands, U.K.) then the following filenames will all be recognised.






When any flight plan is loaded with automatic weather generation the weather engine will display the following banner on the simulator screen for a period of 20 seconds.

OpusFSI Live Weather - Loading Flight Plan : <flight_plan_name>

List All Available Flight Plans For Departure

When ticked this option will display a text list of the first nine available flight plan filenames, ordered from newest to oldest. Select the required flight plan menu number, or click on the plan with the mouse, to load the plan and perform a Full Weather Reload.

Flight Plan Reports

The Flight Plan En Route Weather Report displays the navigation points associated with each listed Met station, refer to the Weather Reports section for further details. The OpusFlightReport text file in the OpusFSI_v6\Weather folder provides details of all cruise winds, cruise temperatures and local weather reports at each of the navigation points.

Deleting a Flight Plan

To delete a flight plan simply press the Reset button.

Add-ons Menu Options


Several flight plan options are provided via the sim’s Add-ons menu (OpusFSI Live Weather option),

·         Departure Flight Plans

·         Load PLN Flight Plan – browse for PLN flight plans

·         Load TXT Flight Plan– browse for TXT flight plans

Departure Flight Plans

Lists all flight plans with the departure ICAO included in the first 7 characters of the PLN filename.  Enter the list entry number or click on the list entry to load the flight plan and update the weather, or select Quit to exit.  

If you edit your flight plan during flight it will automatically be reloaded and trigger a Full Weather Reload.

Load PLN Flight Plan

Browse for and load PLN flight plans. Defaults to the \Documents\<SIM> Files\ folder (e.g. \Documents\Prepar3D v5 Files\). Double click on a listed flight plan PLN file to load the flight plan and update the weather.

Load TXT Flight Plan

Browse for and load TXT flight plans. Defaults to the \OpusFSI_v6\Plans folder. Double click on a listed flight plan text file to load the flight plan and update the weather.


Weather Download Options

Dynamic Weather Options

The default Weather Update settings are 60 minutes and/or 120km (75 miles) travelled. The minimum Live Weather Update frequency and distance is 10 minutes and 32km respectively. The Weather Update period and distance can be set to up to a maximum of 120 minutes and/or 240km (150 miles). Take into consideration your sim cloud draw distance and your ground speed when setting your update time, if the update time is not frequent enough then you may reach the cloud draw distance before a weather update takes place. We recommend setting a Cloud Draw Distance of between 70 and 110 miles in the simulator. The lower setting of 70 or 80 miles will be adequate for low level VFR, and anything from 80 to 110 miles for high level flying. The clouds at the range of the Cloud Draw Distance will either condense into view or dissipate out of view as you fly toward or away from them.

If you do not like change (cloud shifts) and you don't fly beyond 320Km then you can disable weather updates via the simulator's OpusFSI Add-on menu but be aware that if  you eventually perform another weather update, the injected targets may be completely different from the current wind and may cause one or more wind shifts. Alternatively you can save the current weather as a World Theme and reload that theme for worldwide coverage of the weather which will not be updated.

The GRIB Data Validity Period allows you to specify the validity period for the downloaded GRIB cycle data. Each GRIB cycle contains 15 days of forecast data. The validity period can be adjusted between 3  hours and 240 hours in increments of 3 hours. The default setting is 6 hours.  

You can force an immediate GRIB reload via the Force GRIB Reload button.

If enabled the Background GRIB Processing option (default OFF) will process GRIB data (i.e. GRIB data extraction and the data decoding) slowly in the background and does not affect the sim during this period. 

When Enable GRIB Download in Flight is enabled the world wide GRIB data will be downloaded during a weather update, either on the ground or in flight, whenever it is found to be either incomplete or invalid (e.g. is older than the specified GRIB Data Validity Period). When disabled, GRIB download and decoding will only take place when the aircraft is on the ground (e.g. either before flight or after landing).

Sim Friendly GRIB Wind Targets should be enabled along with Enable Wind Stabilisation (Smoothing and Stabilisation) on any system experiencing troublesome wind shifts. The Sim Friendly GRIB Wind Targets option causes the LWE to adjust any 'sim unfriendly' wind changes in direction and speed.

The Sim Friendly GRIB Temperature Targets option causes the LWE to adjust any 'sim unfriendly' temperatures, enable this if the sim is having difficulty maintaining its targets.

Current Data - Weather Servers

Select the required server NOAA, VATSIM or IVAO (remember to disable VATSIM/IVAO's own weather injection).

Tick the Use VATSIM for Missing Data checkbox if you wish to use VATSIM to fill in missing dynamic weather data (not historic) from the other servers, useful for areas such as NZ.  

When the Download NOAA TAFs checkbox is ticked the LWE will download all available TAFs for all METAR stations. This option is only applicable when the NOAA Server is selected. The downloaded TAFs are shown within the OpusFlightReport.txt (FLIGHT PLAN) text report.

Automated Wx Report

Select 'None' to disable the automated Wx (GRIB Download) report completely, select 'OpusFSI Report' for the usual OpusFSI Wx report window, or select 'Simulator Report' for the 'in sim' Wx report window.

Smoothing and Stabilisation


Cloud and Vis Smoothing

Enable Cloud Smoothing will attempt to preserve all cloud layers and coverage surrounding the aircraft. The extent of the preservation zone increases with increased elevation. All Cloud Smoothing is disabled when the aircraft is within 64km (40 miles) of the specified Destination. It is not possible to stop the sim re-positioning the individual clouds but the OpusFSI LWE can preserve the cloud layers, cloud types, cloud bases, cloud depths, cloud precipitation, and overall cloud coverage.

Similarly Enable Visibility Smoothing will attempt to preserve visibility surrounding the aircraft during all weather refreshes and updates whilst you are airborne.

Wind Stabilisation and Control

Enabling the Wind Stabilisation option will fix all upper winds from 4000ft altitude and above to the maximum wind speed specified within Max Upper Wind Strength (set this to zero to specify no limit). This option is intended to completely neutralise all wind shifts within the P3D v4 and v5 simulators. Surface winds and upper wind directions are unaffected. Only the upper wind speed is affected. A suggested value of 3% of your aircraft's cruise speed should be ok (e.g. 8 for 240kt cruise, 9 for 300kt cruise) although some trial and error may be needed. Setting the Max to 2kt would neutralise the effect of all P3D generated wind shifts.

Enable Dynamic Wind Control is turned off by default due to the current problem in P4D and P5D.

Enable Dynamic Wind Control can be disabled on systems that do not cope too well with the direct ambient wind controls, or in multiplayer mode if you experience a problem.

Selective Weather Updates

P5D works OK with selective updates when the Enhanced Atmospheric (Beta) option is disabled.  

Enable Selective Updates uses selective METAR updates and will prevent all cloud shifts. This mode requires the OpusPDK Interface to be active (activated using the PDKSETUP.EXE set up program once after installation of OpusFSI v6). The OpusPDK Interface injects the detailed OpusFSI Dynamic Weather Theme data into the Prepar3D simulator. Before flight, or when either sat on the ground or after issuing a Full Weather Update, the weather engine will prepare the 'in sim' weather in a number of stages. This preparation will be accompanied by several messages appearing in a fixed banner at the top of the sim display. The following weather update messages may be displayed,

  OpusFSI Weather - Selective Update Mode, <action in progress>

Where <action in progress> is one of the following,

  Preparing Weather Data and Met Stations
  Initialising the Local Weather
  Initialising the Regional Weather

As soon as the weather has been prepared and the regional weather injected the banner will be removed and all further weather updating will be performed steadily in the background.

Note, Cloud Smoothing and Visibility Smoothing are automatically disabled in Selective Update mode as they are both unnecessary. We also recommend you disable the Dynamic Wind Control as this may not be functional in the latest P3D v4.5. We would also recommend you set the Enable Max Upper Visibility Limit option in the Weather Preferences dialog and set the Max Visibility to 240km or even as low as 128km. If the option is disabled then the weather engine will unrealistically inject unlimited visibility at medium to high altitudes. If the option is enabled then the upper visibility will be restricted as it mostly is in the real world.

General User Preferences 

The Thunderstorms Require TS Descriptor option (enabled by default) only produces active thunderstorm (CB) clouds when the TS descriptor is specified within the METAR statement. When this option is disabled either TS or CB in the METAR will produce an active thunderstorm.

Enable Magnetic Variance is disabled by default. When enabled, there will be a difference between the reported wind directions METAR and GRIB forecast data which always report directions with respect to True North and the current wind directions within the simulator and reported by ATIS which are always Magnetic directions. To assist the pilot, the LWE will show the current Magnetic Variation in the weather report windows, displayed in the form 'MagVar XX.X' at the end of the surface wind information. You must ADD this value to all wind directions to convert them to Magnetic directions at the current location. Please note, OpusFSI cannot show the Magnetic Variation at the Destination or Alternate sites, only at your current location in the simulated world.

The Maximum Wing Flex level (0 = None, 4 = Maximum) moves the ASI and VSI when the simulator's turbulence and thermal setting is enabled (recommended); in the P3D menu - Options, Settings, Display, select the Weather tab, there is an option for turbulence and thermal effects on the aircraft, make sure it is not disabled. Also enable the 'Advanced Animations' option in the P3D menu - Options, Settings, Display - Graphics tab. Note, the wing flex option can cause some aircraft simulations to loose A/T or A/P lock, if so try lowering the value and if it still causes problems disable it in the sim and here.

High level cirrus cloud is not included within the standard METAR reports. The Auto Cirrus Clouds option (set as default) automatically displays cirrus cloud whenever it determines the weather is quite changeable, possibly due to a weather front. The cirrus cloud coverage is generated randomly between the configured lower and upper Cirrus Altitude Range based on the aircraft's current latitude. The lower range will be adjusted to between 10,000 feet at the poles to 20,000 feet at the equator, the upper range will be adjusted to between 25,000 feet at the poles to 60,000 feet at the equator. The calculated limits are graduated throughout the polar, temperate, and tropical zones. For example, at EGNX East Midlands (latitude 52.8 degrees) the limits are set to range from 15,900 to 43,100 feet. In fairly stable conditions the cirrus cloud will be disabled. In flight, the cirrus is reassessed every 80 miles flown.

Disable Cirrus Clouds if you don't want any cirrus clouds at all, either auto or random.

If you haven't selected auto cirrus or disabled cirrus clouds then the Live Weather Engine generates a single cirrus cloud layer at a random height between the configured lower and upper Cirrus Altitude Range. The valid range of altitude settings are from 10,000ft up to 60,000ft (default range is 16,500ft to 45,000ft).

Low Overcast Effect (disabled by default) comes into force whenever the overcast cloud cover is less than about 6000 feet AGL. You must be IN the Low Overcast Effect to see it. Overcast by definition means 90% or more cloud coverage. Don't expect to see solid blanket type overcast when looking vertically downward ... you WILL see transparent holes just like you do in real life until you get IN an OpusFSI Low Overcast Effect (an overcast below 6000 feet).  Low Overcast Effect can be combined with Volumetric Fog but only when on the ground or at your specified Destination or Alternate sites and can result in reducing the intended surface visibility.

Disable Fog and Mist Effects if required. The mist and fog effects place a thin layer of cloud on the mist/fog layer so that it is visible from above.  

In P3D simulator mode the Enable Volumetric Fog option is set automatically using the VolumetricFog setting within the Prepar3D.CFG file. If you change this setting during a P3D session then either change the Enable Volumetric Fog Effect in OpusFSI to match P3D or restart OpusFSI.  Enabling both the Low Overcast Effect and Volumetric Fog Effect in Prepar3D can result in reducing the intended surface visibility. 

The Enable Max Upper Visibility Limit option is for those users who prefer their upper visibility limits to be reduced, this will also harmonise with the sim's max cloud draw distance, thus reducing any observed hard edge at the cloud draw boundary. The limit can be specified as a value between 80km (50 miles) and 240km (150 miles). A checkbox is provided to enabled/disabled the reducing effect, when disabled the Upper Limit will be set to 0, all values less than 80km will disable the effect. This effect can be adjusted to match the Max Cloud Draw Distance within the sim's Weather settings. Note, changing the setting mid-flight may not have much of an effect if you have the OpusFSI Visibility Smoothing enabled. In Prepar3D you can have a reduced visibility layer above the low lying Volumetric Fog effect.

Realistic reduced visibility is an effect seen in the real world which we have simulated for P3D. You may Ignore (disable) realistic Reduced Surface Visibility by configuring the distance as required, a value of zero disables reduced visibility entirely.

The Default Surface Visibility setting defaults to either 32km (20 miles) or 48km depending on latitude and time of year. The maximum visibility at altitude is usually 128km (80 miles) and attained at or below a target altitude of 28,000 feet. This maximum visibility can be reduced to 96km (60 miles) whenever average surface visibility is reduced below some predetermined distance depending on your Max Surface Visibility setting. Of course when using Dynamic Weather the visibility values in the METARs will override this setting so it only comes into force when the METARs state CAVOK, 9999 or 10SM conditions. The forecast land/sea visibility data will be downloaded and factored into the Live Weather Engine's modelling of the Default Surface Visibilities used in areas not covered by actual METAR reports.

Recommended Settings and Practice

Upgrade to the latest Release or Beta Version.
Set all Defaults in all weather dialogs. *
Specify your Destination.
Specify your Max Cruise Altitude. 
Update the Weather. **
Check the Weather ***

* This will enable the cloud and visibility smoothing, wind stabilisation and dynamic wind control options in the Weather Smoothing dialog.

** If you have specified Background GRIB Processing in the Weather Download Options dialog then the GRIB data extraction and lengthy decoding will proceed at a slower pace and can take several minutes. Otherwise the processing will be done as fast as possible at the expense of sim performance or frame rates. The GRIB Data Validity Period allows you to specify the validity period for the downloaded GRIB cycle data between 3 and 240 hours in increments of 3 hours (default 12 hours).

*** Before flight you should get into the habit of checking the weather. At the very least display and check the Opus Local, Lower, Upper, and Destination Weather reports. You may also like to examine the various Opus text reports accessed via the sim Add-ons menu. There are separate reports showing the downloaded METARs, all the GRIB wind and temperature targets from 4000 feet up to FL540, all the en route weather for any specified flight plan including TAFs if you have enabled them, and finally an easy reference to all relevant SIDs and STARs. This report gives a handy direction and bearing for each listed SID and STAR.

The Opus weather reports (e.g. The Destination Weather) should be checked during climb and descent to monitor all wind and temperature targets, compared with the actual sim ambient conditions. This way you will know that your sim is operating as expected.

Never disable weather updates, the sim will NOT cope on its own it simply cannot contain all the necessary data.

Text Weather Reports, located in the OpusFSI_v6\Weather folder and accessed via the sim Add-ons menu or the Wx Report button on the FSI SERVER form ...

OpusWeather.txt ... The downloaded METARs
OpusWeatherReport.txt ... The GRIB data report
OpusFlightReport.txt ... The flight plan en route weather report
OpusSIDSTARReport.txt ... The relevant SIDs and STARs

Live Weather Assistant (LWA) and Weather Map data ...

Surface Visibility
Precipitation Levels
Surface QNH
Surface Temperatures
Cruise Level Temperatures
Upper Level Temperatures
Surface Winds
Cruise Level Winds
Upper Level Winds
Cruise Level Turbulence
Upper Level Turbulence
Lower Level Cloud Cover
Medium Level Cloud Cover
Met Station Cover

The LWA and up to six weather maps can be displayed on the server or a networked client.

Remember ...  You should use all the various Opus weather reports and text report files to check your weather before and during flight. Especially BEFORE you fly. At the very least examine the Opus on-screen weather reports.

BEFORE flight ...

1. Check the Local weather report and confirm the weather has been injected OK.
2. Check the Lower Atmosphere weather report to confirm you have GRIB data downloaded and decoded. It will also show you what winds and temps to expect as the LWE takes you up to FL200 and the GRIB forecasted winds and temps.
3. Check the Upper Atmosphere weather report, again to confirm the GRIB data is downloaded and in use. This will also confirm the expected upper winds and temperatures.
4. Check your Destination weather report, if not within the current weather map then check the Destination report in the En Route weather reports. Then you will be warned of any adverse weather at your Destination.
5. If you have processed a flight plan then check the OpusFlightReport.txt file. You can access this via the Add-ons menu or directly, you will find it in your OpusFSI_v6\Themes folder. The file content is self explanatory. 

Other Comments and Useful Hints ...

Both the Lower and Upper Atmospheric reports, and the OpusWeatherReport.txt (GRIB Data) report file contain details of the actual downloaded GRIB data cycle. In addition, each weather report contains the METAR day and time code.

There should never be any need to question the validity of the forecasted data. All the weather related information is available for you to examine, as you should do before every flight.

The OpusWeatherReport.txt (GRIB Data) text report shows ALL the forecasted and Opus 'Sim Friendly' adjusted upper wind and temperature target data from FL040 upwards. All data from FL200 and above being derived directly from the actual forecasted GRIB data.

Specify the altitude you are going to spend the most time cruising at in the Max Cruise Altitude. If you set the Sim Friendly Options (Recommended to minimise weather updates amongst other things) then the software will ensure the raw GRIB forecasted data is adjusted (sim friendly adjustments) about this reference altitude. Of course the GRIB forecast is only adjusted when needed at each 500 foot level. You can see the results of this in the OpusWeatherReport.txt (GRIB Data) report file and the Upper Atmosphere Report.

Helpful hints ...

If the upper winds, above FL200, all veer upwards above your lowest stepped altitude then they will not be adjusted by the Sim Friendly option. This option allows veering wind directions and increasing wind strengths and only adjusts those that are backing (rotating anti clockwise as you climb) upwards.

You can compare the adjusted and raw GRIB in both the text report file and in the Upper weather report.

The actual GRIB data cycle is also identified. There is 360 hours (15 days) of global forecast data in each cycle. The cycles are never posted on time as that identifies the time of the forecast cycle and not the time of release. Cycles can in fact be posted anything up to 9 hours after the cycle time.

There should be no need to force a weather update, the LWE will update automatically to keep all the wind and temp targets appropriate to the current altitude zone. It is usually best to leave the LWE to monitor and adjust the winds dynamically (you will need FSUIPC installed for this).

Use the various on screen weather reports and the shift-Z info bar to monitor your ambient conditions (wind) checking against the targeted wind in the weather report for your altitude.

Start off using all default settings. Get used to monitoring the targets against the current ambient wind.

I usually position the weather report window immediately below the shift-Z info line. I monitor the Lower report during the climb below FL200 then switch to the Upper report as I continue to climb up to my cruise altitude. Then I usually monitor the Destination weather report.

Never use accelerated time during the climb or descent, give your sim and the Opus Dynamic Wind Control (DWC) the best possible chance to maintain its targets. In the cruise if you must use accelerated time only use x2, x4 with supervision. Not all aircraft sims are designed to work in accelerated time.

The above weather checking and target monitoring will confirm that your sim is performing as expected. The DWC on the vast majority of systems will hold the winds within 2 degrees and 2 knots of the desired target values. Remember DWC does require FSUIPC.


Historic Weather Data

Set your simulator time to the required time you want to load within the past 24 hours. In the Weather dialog tick the checkbox for Historic Weather.


Weather Data Import (current and historic)

There are three methods you can use to import your own weather data,

·         a global METAR specified in the weather dialog

·         a text file containing a list of METARs

·         a named world weather theme  

METAR Import

Global METAR


The Global METAR Conditions checkbox and combo box option in the Weather dialog is used to select and specify global METAR conditions for use in the sim. 

The global conditions are specified in standard METAR form excluding the ICAO and Day/Time code at the start. In other words excluding the "ICAO DDHHMMZ" phrase at the start. For example, the string "27004KT 2000 SCT042 04/01 Q1018" would specify a surface wind of 270 at 4 knots, visibility of 2000 metres, scattered cloud at 4200 feet, temperature 4, dew point 1, and a QNH of 1018mb. The dropdown list stores a history of your METAR conditions.

Text File Import

As an alternative to the weather data collection over the Internet the software can be instructed to import its METAR data from a user specified import file (with the file extension txt). You can create your text file in packages such as Notepad.

The METAR Import File Specification and file scan frequency (default 3600 secs) is specified within the Weather dialog on the server.  

This interface provides the means for you to perform instant weather updates across the OpusFSI system with all the benefits of using our Dynamic Weather update. In such circumstances, the OpusFSI weather engine will load all METARs created by you that are contained within the specified text file. These reports will be used to perform a weather update of the system.

This interface can also provide you with a simple means to create your own localized or global weather themes by specifying the required METAR string(s) within the import file. The global ICAO station code GLOB can be used to specify global weather and overrides any other METARs in the file.  

The METAR date/time is ignored and so can be set to any date/time. Also the word METAR, MET or SPECI is ignored if present in the file. The METAR must be on a single line.

Example: KORD 010203Z 19020 6SM -SHRA BKN070 12/08

decodes as station id KORD, wind direction 190 degrees, 20 knots, visibility 6 Statute Miles, light rain shower, broken cloud at 7000 feet, temperature 12 degrees Celcius, dewpoint 8 degrees Celcius.

If you want to use the above weather conditions at any location then substitute KORD for GLOB.

Example: GLOB 000000Z 27008KT 7000 OVC004 03/02 Q1003

sets the visibility to 7000 meters with an overcast ceiling at 400 feet.

The OpusFSI Live Weather Engine (LWE) saves all downloaded METAR statements into an OpusWeather.txt file. We use this method to reload a user's weather if they report an anomaly they want us to look into.


World Weather Themes

The OpusFSI LWE can save a snapshot the current worldwide weather (METARs and GRIB forecast data) as a named weather theme for you to reload at any time and place in the future. You can use this feature to save interesting weather scenarios anywhere in the world. You can simply build up a library of interesting weather scenarios of your own, or even swap weather themes with others.  

To save a theme ...

Let the LWE construct the detailed weather map. After it has loaded, save the weather theme using the OpusFSI Live Weather, Save World Weather Theme add-on menu option, or the Save Current Weather as World Theme button in the Weather dialog. 

If you save the theme via the Weather dialog then you have the option of naming the theme. 

If you save the theme via the add-on menu all theme files are automatically stored in the \OpusFSI_v6\Weather\Themes folder in a file named 'WWT_yyyymmdd_hhmm'. If you wish to rename a theme saved via the add-on menu you must remember to rename both the theme's dat and txt files, and you will need to restart OpusFSI for the filename changes to take effect.  

If historic weather is loaded then the simulator's current Zulu time will be assumed, otherwise the LWE will download the current real-world Zulu time over the Internet, defaulting to the computer's current Zulu time on failure.

World Weather Themes cannot be saved before the weather has been generated, nor can they be saved when either of the Import METAR Data From File or Enable World Weather Themes options are ticked.

To load your saved theme ...  

World themes can be loaded via the simulator's add-on menu. First select the Load World Weather Theme option within the Live Weather menu. The displayed window will provide a directory of all World Weather Theme filenames along with their saved Zulu date and time. Use the Display Previous and Display Next options to navigate the pages. Click on the required filename to load the weather theme, the weather will automatically be injected into the sim.

Loading a World Weather Theme via the Add-ons menu will automatically display the Weather Report menu ready for you to check the loaded theme weather and GRIB forecast data prior to flight.

Alternatively tick the Enable World Weather Theme checkbox in the Weather dialog.

Select the Browse for World Weather Theme button and Browse for the required theme file.

Select Update to load the weather theme and inject the weather into the sim.    


If a World Weather Theme does not include any GRIB forecast data (i.e. the theme's data file is missing) then the Enable GRIB Forecast option in the Weather Downloads dialog will determine whether the current GRIB data cycle should be downloaded and used.

The Disable World Weather Theme option in the add-on menu can be used to disable the World Weather Theme mode and revert back to using the current live weather.

Many OpusFSI users like storm chasing, the saved themes can be used to repeat the experience at some other time of your choosing. You can use the OpusFSI Weather Locator to find interesting current weather to capture and reload.

Editing A Theme

You can tweak or change the surface weather at a location by editing the relevant saved theme text (.txt) file in the OpusFSI_v6\Weather\Themes folder. Search for the ICAO code for the METAR you wish to change and then edit its content. That way you can change the surface conditions at that site. The saved World Weather Theme text file can be edited using Notepad.  

Networked Systems

The use of weather themes is efficient and guarantees consistent weather and cloud formations across all networked systems. Weather themes do not require the transfer of METAR reports from the server to client systems.

To ensure correct synchronization, the desired weather theme for the flight must be selected in the FSI SERVER's Weather dialog, and not via the usual sim Weather menu. If at any time the weather or cloud formations differ on your client machines, possibly due to you manually pausing one or more of the simulators, this can happen as a result of displaying a sim dialog, then you can quickly resynchronize the weather by displaying the Weather dialog on the FSI SERVER and clicking on the Relaod button to reselect and reload (i.e. synchronize) the chosen weather theme. You may of course choose to browse for a new weather theme and select that.

This procedure may also be required after the client systems have first connected. For example, when you have not prepared everything, including the weather theme, on the server system before the client connections are made. In either case, the resynchronization is almost instant.  


Weather Relocation

Weather relocation enables you to experience the weather conditions from anywhere in the world whilst still flying at a favourite location or with your favourite scenery. For example, you will be able to experience tropical weather in the middle of winter at Gatwick U.K.

Weather relocation will work with any source of OpusFSI weather data, whether it be the current Live Weather, Historic Weather, or a specified World Weather Theme.

The Weather Relocation option consists of an enable checkbox and separate FROM and TO textboxes for your specified aerodrome ICAO codes. When enabled, all weather will be relocated or offset in latitude and longitude to move or relocate the weather using the specified FROM and TO locations, i.e. the whole world's weather is rotated about the globe. The ICAO code for either the point of departure or the destination would typically be specified in the TO box. To aid entry, an empty TO box will automatically be filled in with the nearest aerodrome details whenever the FROM box is edited.  

To get appropriate cloud textures etc for the weather you may need to change the Time and Season in the sim to match the weather you require.

The Weather Overview/Locator (Server dialog) can be used to either locate specific weather conditions on the map area that match your specified criteria, or obtain a Weather Overview of the general weather conditions. This is very useful for locating any weather you are interested in globally, or viewing a simple overview of the weather in a specific region of the world.

The on-screen Flight Plan En-Route weather reports and generated flight plan text and report files are disabled in Weather Relocation mode.  

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