Below is a flight plan from PFPX and i can't figure out why each waypoint time at each Expected weather conditions is the same and the time decreases?

 

 

 

 

 

 

 

Concise weather briefing:

 

- Average winds (temps): 182/49 (-27.12), Temp at TOC: -47.00,  Head wind component: -51.51, Your selected flight level has the most favorable winds compared to adjacent levels

 

 

 

Detailed weather briefing:

 

EGFF: (Calculated flying altitude 200 feet)

- ETA in 0 minute(s) 0 second(s)

- Expected weather conditions: EGFF 062120Z 19006KT 9999 SCT045 12/06 Q0997

- Expected winds: 190/6

- Expected temperature: 12.00 celsius

 

BCN: (Calculated flying altitude 7400 feet)

- ETA in 4 minute(s) 39 second(s)

- Expected weather conditions: EGFF 062120Z 19006KT 9999 SCT045 12/06 Q0997

- Expected winds: 241/14

- Expected temperature: 2.70 celsius

 

DIKAS: (Calculated flying altitude 10100 feet)

- ETA in 5 minute(s) 18 second(s)

- Expected weather conditions: EGFF 062120Z 19006KT 9999 SCT045 12/06 Q0997

- Expected winds: 235/15

- Expected temperature: -0.80 celsius

 

TOPRO: (Calculated flying altitude 13100 feet)

- ETA in 6 minute(s) 50 second(s)

- Expected weather conditions: TOPRO 062109Z 17405KT 9999 SCT051 10/06 Q0997 RMK ADVANCED INTERPOLATION RMK BASED ON FORECAST GRID DATA

- Expected winds: 214/26

- Expected temperature: -8.80 celsius

 

NITON: (Calculated flying altitude 26900 feet)

- ETA in 13 minute(s) 34 second(s)

- Expected weather conditions: EGOS 062050Z AUTO 21001KT 9999 NCD 05/04 Q0997

- Expected winds: 190/66

- Expected temperature: -34.30 celsius

 

TOC: (Calculated flying altitude 28000 feet)

- ETA in 14 minute(s) 4 second(s)

- Expected weather conditions: EGOS 062050Z AUTO 21001KT 9999 NCD 05/04 Q0997

- Expected winds: 184/75

- Expected temperature: -47.00 celsius

 

NOKIN: (Calculated flying altitude 28000 feet)

- ETA in 18 minute(s) 59 second(s)

- Expected weather conditions: EGNR 061950Z VRB01KT 9999 FEW035 07/05 Q0998

- Expected winds: 184/75

- Expected temperature: -47.00 celsius

 

CROFT: (Calculated flying altitude 28000 feet)

- ETA in 24 minute(s) 41 second(s)

- Expected weather conditions: EGNH 061950Z 11006KT 9999 FEW020 07/05 Q0998

- Expected winds: 184/75

- Expected temperature: -47.00 celsius

 

RIBEL: (Calculated flying altitude 28000 feet)

- ETA in 28 minute(s) 43 second(s)

- Expected weather conditions: EGNH 061950Z 11006KT 9999 FEW020 07/05 Q0998

- Expected winds: 184/75

- Expected temperature: -47.00 celsius

 

SHAPP: (Calculated flying altitude 28000 feet)

- ETA in 33 minute(s) 46 second(s)

- Expected weather conditions: EGNC 062129Z 21002KT 9999 FEW019 SCT026 12/08 Q0997

- Expected winds: 169/80

- Expected temperature: -46.80 celsius

 

MARGO: (Calculated flying altitude 28000 feet)

- ETA in 35 minute(s) 54 second(s)

- Expected weather conditions: EGNC 062129Z 21002KT 9999 FEW019 SCT026 12/08 Q0997

- Expected winds: 169/80

- Expected temperature: -46.80 celsius

 

TOD: (Calculated flying altitude 28000 feet)

- ETA in 38 minute(s) 39 second(s)

- Expected weather conditions: EGNC 062129Z 21002KT 9999 FEW019 SCT026 12/08 Q0997

- Expected winds: 169/80

- Expected temperature: -46.80 celsius

 

EGPF: (Calculated flying altitude 0 feet)

- ETA in 52 minute(s) 47 second(s)

- Expected weather conditions: EGPF 062120Z AUTO 08003KT 9999 NCD 05/04 Q0998

- Expected winds: 80/3

- Expected temperature: 5.00 celsius

 

IE 062120Z     062129Z      061950Z

Hi Vernon,

 

I am not sure I understand. Only thing I can see in the briefing is a flight plan from EGFF to EGPF and the ETA (expected time of arrival) increases as it should.

 

Unless your report is about the waypoint depiction on the map. In this case if you hover the mouse over such a way point (and depending on the current aircraft position), then it's normal for the "time remaining" to reduce as the aircraft closes to the way point.

 

I'm sure I missed something here.

Hi Kterz, i was referring to the time part IE  062120Z ? they basically stay the same, i just thought this would be the ETA time for each waypoint

OK, I got your question now:

 

In short hauls like this one (less than 4 hours), ASN does not use the TAF info of the metars (if any) when the waypoints are relatively close. Instead, it considers the current metar active (it uses the "raw data" metar), so the zulu time is the time this metar was actually issued. This explains what you noticed .

 

On the other hand, when ASN parses long hauls (more than 4 hours in length), it actually parses the taf (and the aloft data active for the calculated forecast period) to create the predicted weather conditions at the waypoint at the specified ETA. 

 

ASN behaves similarly in conditions page (current metar conditions are shown when the forecast slider is at a value of less or equal than 4 hours and forecast data are utilized only when the slider is set to > 4 hours).

 

Hope this clears things a bit 

So with any flights under 4 hours the weather conditions at each waypoint is subject to change is that right? So if it reports winds at 170/45 at BCN and it will take me 2 hours to get to that waypoint. These winds will be different?

Winds or weather are subject to change even within 10 minutes. All we're talking about here (in the briefing section) is predictions. TAF information is always prediction and it may also not be certain (you may have noticed "PROB30" sections included in certain cases). It doesn't mean that the TAF information 6 hours from now (as interpreted by ASN)  will be 100% this way and it's certainly equally likely/unlikely for this to be true in the next 2 hours. In this case the "weight" of the current metar is increased compared to the taf though.

 

So, the way ASN works is it considers current metar conditions to be probably the same for the following 4 hours and after that it uses the TAF info (if any) to increase the prediction accuracy.

 

In reality things work pretty much the same. If weather conditions are subject to change within less than 2 hours from the time the METAR is issued then a TREND forecast is included in the metar itself (you may have noticed the presence of NOSIG in some cases: This means that the conditions will probably stay the same for the next 2 hours)

Thanks for that detailed explanation i get it now!

 

Well is it true you can't get TAF's throughout your flight only at your origin and dest? As these are terminal aerodrome forecast? And won't relate to your cruising alt.

 

So each way point will offer a METAR every 6 hours? If it changes in the less time you get a TREND?

No, waypoints also get their forecast weather from the closest weather station with this data available (using interpolation). In SP1, if the data "accuracy" is relatively low (e.g. the closest station with valid data is more than 30-50 nm from the waypoint), we use the new grid based forecast data (as you see in the waypoint TOPRO in your example plan). This is true both for actual weather depiction in the sim (e.g. over the ocean) and for predictions (briefing etc). 

 

So, with SP1 overall accuracy has increased significantly and we'll keep improving it.

Ah cool i see so it will give you accurate weather briefing for that waypoint at that cruising alt?

Short answer: yes,

 

ASN will attempt to calculate the waypoint flying altitude (either cruise altitude or a calculated one in case it's in the climbing or descend phase) based on the provided flight plan parameters. And then it will calculate winds and temperature using the matching forecast aloft data. It also reports the forecast surface data of the closest weather station (e.g. in the example flight plan you provided the waypoints MARGO and SHAPP both use EGNC as source for surface conditions).

 

In general ASN is designed to provide the best accurate predictions based on the available data it has but this also depends on the accuracy of the provided plan data. If for example the rate of climb is not set correctly, then ASN will miscalculate TOC and TOD waypoints, so any waypoints in the SID/STAR may have wrong flying altitude calculations, thus predictions may be different to what the aircraft will encounter. Similarly, if the plan loaded to ASN does not contain e.g. the STAR (that in some cases is very long), predictions will be suboptimal. This (providing SID/STAR support) as well as other additions (like e.g. step climb support, navdata support for proper routing etc) are planned features for future product versions, but we have to keep in mind ASN is first of all a weather engine and not a flight planning tool. Nevertheless, the weather predictions as provided currently by ASN (even without the SID/STAR waypoints included) are sufficient in most cases. 

Thanks again. I hope this topic is also usefull to others!

 

Maybe you should include SID and STARS in a future update. Its still all accurate enough like you said.

 

Also for thought can you add ISA temp also at each waypoint and maybe include the runway available during the ATIS for the dest?

Also may i add, will you's ever add in low pressure and high pressure systems to the map mode so we can see them?

Hi,

 

we'll give these suggestions a thought. Please post them in the related section of HiFi's forums ("suggestions"), to help us keep track of them.

 

Thanks!

Hi it won't let me its private even though i'm reg

EPSC 191130Z 1912/1921 18010KT CAVOK BECMG 1915/1918 BKN023 BECMG 1918/1921 26010KT TEMPO 1918/1921 4000 RA BR BKN007 BKN015

 

 

above is a recent TAF, you have different reporting times and dates like 1915/1918 BKN023 - does this mean the weather will change between 1500z to 1800z to broken clouds at 2300 amsl?

EGGP 191100Z 1912/2012 22018KT 9999 SCT030 TEMPO 1912/1918 24021G33KT PROB30 TEMPO 1912/1919 7000 SHRA BECMG 1918/1921 28011KT BECMG 1923/2002 22009KT PROB30 TEMPO 2004/2011 7000 SHRA

 

 

also can you help me understand this. You have two times here EGGP 191100Z 1912/2012   1100z and you have 1912/2012 what are these midnight on the 20th or something?