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Weather Reporting and XM Weather

JonJay

JonJay

Well Known Member
Newly armed with my 496 and "fresh" report from Weathermeister (love it), I departed for a relatively short jaunt, 145nm, to Eastern Oregon under rainy skies. Winds where reported at my destination from 240 18kt -24kt gust, manageable at that airports rnwy 22. ALL weather stations along route and in area where reporting decent cielings, no rain (which was present everywhere), and VFR conditions, (which turned out to be spotty at best).
Ceilings kept dropping as I entered the Columbia River Gorge, along with visibility, harder rain, and low level clouds. Working through the Gorge for about 15 miles, a narrow corridor with mountains on both sides of several thousand feet high, at 900 feet 5 miles vis., then less? Well, time to turn around, miss my meeting and live to tell about it. Last thing I needed was for weather to close me into the Gorge with no airport option in either direction. A PIREP an hour later from a 206 reported 1000' ovcst 1m. He turned back too.
Anyway, I have been watching the reporting change through the day finaly catching up with my reality. I guess I am surprised with all of the technology we have out there that our systems are so poor.
My 496 was not a lot of help either. I think it is a great tool to show really bad cells and broken weather, but for scud, it does not seem to do much good. Perhaps there are some settings I need to fiddle with, but if it showed low level scud and light rain on the map, you would not see anything else I guess.
Living and learning, or learning and living perhaps.
 
Safety First!

Yeah, sometimes you have to read between the lines on all those reports showing "VFR conditions." I personally think that a lot of the automated weather reports are completely unreliable. I have called the Millington, TN AWOS and heard the recording say the ceiling is greater than 12,000. But at 2M8 (3 miles away) it would be much worse than that.

You're right about the 496. It's great for avoidance of thunderstorms and heavy rain, but lousy at showing low level scud. We can only hope that new technology will evolve that will make weather reporting better. In the meantime, be careful!
 
The METARS and TAF would be a good source of info to put the whole picture together. Just pay attention to the time of the METAR and if it is an automated source, be cautious.
 
JonJay said:
My 496 was not a lot of help either. I think it is a great tool to show really bad cells and broken weather, but for scud, it does not seem to do much good. Perhaps there are some settings I need to fiddle with, but if it showed low level scud and light rain on the map, you would not see anything else I guess.
Living and learning, or learning and living perhaps.
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I don't yet have XM weather, so please bear with me as I ask potentially stupid questions.

Which of the available XM data would we expect to show actual cloud coverage at a particular altitude? What is the source of this data? What technology does it use to detect cloud?

The NEXRAD data would only see precipitation, not cloud, and it would only see the precipitation if there was a clear line of sight between the radar and the precipitation. If the precipitation was occurring at low altitude in a valley, it is quite possible that the radar would not see it as the radar would be blocked by the mountains on the side of the valley.

XM weather is a great advance, but we need to figure out what its limitations are if we are to obtain a safety benefit.
 
Kevin Horton said:
Which of the available XM data would we expect to show actual cloud coverage at a particular altitude? What is the source of this data? What technology does it use to detect cloud?
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The only XM weather data product that graphically shows cloud coverage is the Satellite Mosaic product, which is available with the $50/month package. This data is derived from the GOES IR satellite image, which looks at the difference between cloud temperatures and surface temperatures. It does a good job of detecting large areas of thick cloud cover that extends above 10,000 feet, but it does not tend to discriminate small areas of low clouds or scud. The satellite also doesn't know anything about the cloud bases, since it's looking down from space.

I suppose that it also goes without saying that the 496, or anything else that displays datalink weather, is only as good as the data being supplied to it. (Well, I guess I just said it anyway) For getting the true picture of where the clouds are, the best available technology is a pilot's informed use of all available data sources: datalink weather, METARs, PIREPs, ASOS/AWOS/ATIS, local knowledge, and the Mark I eyeball.

fly safely,
mcb
 
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Metars are from too few reporting stations especially with mountain weather patterns being so volatile. And keep in mind that the airports are in lower alt open spaces so very different from passes. And Kevin is right, radar will not show clouds or ceilings, and Metars will but only at the few and far between metar sites.

Here in flat and low alt Illinois I can get by on Metars that are 50-100 miles apart and expect the weather in between to be fairly similar. In the mountains I would think you'd have to get pretty weather smart and look a lot deeper into fronts, systems, temps and dewpoints. Metars won't tell you much as far as the future as things can change SO dramatically in so short a time.

I think XM is much more an IFR tool. The only time it would help me is if I want to fly on top and it can tell me where I can find broken or scattered to get back down through. For $600 bucks a year for XM I think I'll just call flightwatch as long as I'm still just a VFR pilot. Love my 496 but no plans to turn on XM right now. Too expensive for too little utility for my flying.
 
I disagree

grantcarruthers said:
...

I think XM is much more an IFR tool. The only time it would help me is if I want to fly on top and it can tell me where I can find broken or scattered to get back down through. For $600 bucks a year for XM I think I'll just call flightwatch as long as I'm still just a VFR pilot. Love my 496 but no plans to turn on XM right now. Too expensive for too little utility for my flying.
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Sorry, Grant. I disagree. There are two packages of XM Aviation Weather available for the 396/496 - the Aviator and the Aviator LT (Light). The LT package is only $29.95 per month (~6 gallons of avgas), and I think it's well worth the money especially for a VFR pilot. I think the weather data it presents is much more useful and up-to-date than what the FSS provides inflight. I have no interest in scud running or even getting close to the stuff (again!), but I do like to see and know what's going on between me and my destination...horizontally. As for VFR on top and trying to find a "sucker hole" with XM Weather? I hope my flight planning and decision making would keep me out of those situations. They have for nearly 25 years.

XM Weather's not perfect, and I'm sure it'll get better, but I like it. Plus, I can listen to Jimmy Buffet!

Different strokes for different folks. :D!

Don

P.S. I subscribe to Weathermeister and love it, too! Double big :D:D!!
 
Last year...

.......was my first as a 496 owner and I couldn't have been more satisfied, even with the cheapie subscription. We often suffer 3 and 4 mile visibilities in the summer down South and have many embedded T-storms.

In my ag flying, I work a 35 mile radius and the 496 has often saved my butt from inadvertent C-nimbus entries. I transfer it to the RV for our day trips and the ability to see beyond our fuel range, buildups to avoid sometimes mean only a few degrees of heading change since we can see them so far ahead.

I have to agree with Paul's writeup when he first used the 396 flying from Tx to Cape Canaveral.

Regards,
 
XM weather is purely a strategic instrument for planning and looking out a few hundred miles to know what you are going to encounter. It is also good for TAFs/Metars in the cockpit without the hassle of calling FSS or flight watch.

It is not good for trying to penetrate a line of thunderstorms or finding a small hole in an overcast. It is absolutely useless for scud running.

Nexrad is not going to show anything in a canyon nor will IR sat. Visible sat is not available on XM.

It will tell you fairly accurately where an overcast ends or turns into a broken/scattered layer. Observing several METARS along your route will give you a FAIRLY accurate picture of ceilings and visibility. As noted in a prior post it is only as good as the input which comes from the same sources we have always used.

I would not expect it nor would I rely upon it to navigate a mountain pass under an overcast. Your best tool here is personal knowledge of local weather and how it behaves.

I frequently fly Southeast to Northwest across Arkansas. Seldom does XM portray a good picture of conditions over the hills and ridges in central Arkansas. An area which seems, to me, to always have crappy flying conditions.

XM weather is great but don't bet your life on it.
 
rv7boy said:
. I think the weather data it presents is much more useful and up-to-date than what the FSS provides inflight.

As for VFR on top and trying to find a "sucker hole" with XM Weather? I hope my flight planning and decision making would keep me out of those situations. They have for nearly 25 years.

Different strokes for different folks. :D!

Don

Don, please don't miss-quote me and attribute statements to me I didn't make and make me sound reckless!! Unnecessary and quite unfair I'd say.:confused:

Who said anything about looking for sucker holes? I have never even come close to being stuck on top so my preflight and inflight weather interp and risk avoidance must be just fine, all without using XM. If I had XM I might do it more as the info is easier to visualise and doesn't take as much effort.

And as far as FSS info I'd guess they have it just as fast if not faster than XM. They get the reports from the same sources and then XM has to wait to transmit the update. FSS has it available right away. If Nexrad is as old as 20 minutes I doubt the metars are much better. Best case they have it at the same time. When I've borrowed an XM equiped plane I have frequently completed the flight by the time all the XM data finally comes through, not impressed. Not real useful for short VFR hops of 30 minutes and under 100miles which is 80% of my VFR flying.

I'd love to have it but just don't think its worth 360-600 a year right now for VFR flying which is what I actually did say??

I can look up ADDS and in 10 seconds have everything XM would supply without waiting 20-30 minutes for it to come through. Sure there are times XM would be useful but it comes down to a few times a year and isn't worth the money. If I flew more, farther, IFR, or for hire like Pierre then it would be worth it. To many it is. To me not so much.

Cheers.:)
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XM Weather is great!

I bought my 396 at Oshkosh in 2006 and on the way home I made a fuel stop in Northern Kentucky. While I was on the ground, I called FSS for a weather briefing and filed my flight plan. The briefer indicated there were some scattered clouds and some precipitation near my flight path but most of it had passed my location and I should have a good trip. About 15 minutes later as I was climbing away from the pattern and getting on course, the 396 showed a big red and orange blob directly on my flight path and about 20 miles away. Of course I could see it visually, but the XM really let me know what I was seeing.

To be fair, I don't know if the briefer didn't see the thunderstorm on his screen or if it just popped up after we talked. I made a quick 180 back to the field, waited an hour and then took off again. The trip home was uneventful. I was really glad I had XM weather.

Some folks like XM and I guess some folks don't. Just like a lot of other things in life. :eek:

Don
 
Changing Conditions.....

The best thing I can say about XM is that it allows you to keep up with changing conditions in flight. If you are flying locally, and are ready to land when things don't look as forecasted, then XM doesn't add much for you. But when you are launching on a long cross-country, it allows you to keep up with the ever-changing weather along your route without having to land to get a picture, or call FLightwatch and build a mental picture from a verbal description.

XM is a tool - not a crutch. Like all tools, it allows us to do more than we could without it. Also like any tool, cautions must be observed when using it. When was the last time you bought a tool that didn't have 12 pages of safety warning before th single page of actual usage instructions? Same thing....

I don't "bet my life" on XM, because I don't bet on anything - I don't gamble. I use the XM to make better, more informed decisions on courses of action that I will take. Always evaluate the data to see if it is fooling you, or being fooled, by local conditions. I agree 100% that local knowledge of how reported conditions translate into reality is extremely important, and if you don't have that, you need to be very careful with any data you recieve - from any source!

Paul
 
Full "Aviator" subscription?

Can anyone comment on whether the full $50/mo subscription is worth buying?

I've had the Aviator LT on my 396 for a couple of years and really like it, but I'd like to know how much more utility you get from having the satellite mosaic, winds aloft, and other stuff. Winds aloft forecasts are only issued twice per day, so is XM simply re-broadcasting the same data for 6 hours?
 
XM weather is fantastic for VFR cross country. It lets you "see" ahead sooner an deviate sooner. With today's avgas prices that's a good thing. :p

I love my weather subscription on my 496. I use it every flight. Around here in the South it helps you keep a good an eye on thunderstorms that have a nasty habit of popping up on a moment's notice. It's also great for getting METARS before you're in radio range to pickup ATIS.

I really don't see how more information, near real-time could be a bad thing???
 
When not flying I have the 496 mounted on the dash of my truck. I use it as a quick glance speedometer, turn x turn, and weather info all the time. We have had a lot of weather lately so the $50 a month service is cheap and well worth it.

Using the "Winds Aloft" feature can save you big money on fuel or time. This Sat I left a flyin B-fast in the -3 taking off 10 mins behind a much faster RV-9A. I looked at the "Winds Aloft" and found a 40 MPH tail wind at 9,000'. I beat them back to the hanger. They sure had a puzzled look on their face.
 
Beware!!!

Now that I've got your attention!!! The XM weather is the greatest thing since.... I've got the $50 package and love it. I had a similar experience coming out of Osh last year and heading to South Carolina. Got the official weather briefing and took off. REALLY bad!!! I used the 496 to take me farther West than planned and then on course. Without the 496 I would have gotten back in line at Ripon and stayed another day.

Now the thing to be aware of. If you plan to use your weather feature in more the one vehicle, do not permanently mount your XM antenna in your plane. The antenna has the subscription, not the 496. I wanted to buy another XM antenna to use the 496 in the medical helicopters I fly. Can't do it unless I get another subscription.

So, on my days off, I'm going to be removing my XM antenna from my 7 and making it more portable for use in the helicopter.

Just something to think about.
 
Yup, Darwin has it right about keeping the XM antenna "portable" - I have enjoyed using the 396/XM combo in ground vehicles, so I just throw the antenna on the glare shield.

As to the high/low subscription, I have the Full package, and Louise has the Lite version. To be honest, the extra features I have are ones that I rarely use. The cloud mosaics are pretty low resolution, and what I really want to know is if I have good ceilings and visibilities on my route of flight - I can get that by looking at the METAR's (which are in the Lite package). I used the winds aloft when I first go the unit, but then I discovered Weathermiester, and get great wind info before I leave the ground - the winds that you get on XM are forecasts, and they don't change much over the course of the flight, so I don't think I've looked at them on the 396 much since.

I guess I haven't really missed the "deluxe features when flying Louise's plane on cross-countries, so for my usage, the Lite is actually fine.

Paul
 
XM for me

I got my XM setup over a year ago. I use the controlvision AnywhereMap with a bluetooth XM receiver. Just FYI.

It in my opinion, is the greatest thing since GPS for pilots who fly a ton of VFR (me for instance).

My "daily" commute (now down to twice a week because of gas prices) from 28TE to KEYQ (San Antonio to Houston) would be much more of a trial without in flight weather.

Even on "clear" days, the south Texas weather can change radically during my one hour flight. I have the aviator lite package. On my moving map, I can see any CB activity and steer clear if it's not too wide spread or solid. I can also get a general picture of ceilings and visibilities far beyond what I can see from the cockpit. AWMap has symbology that quickly shows ceilings and viz for all reporting stations on the screen. Updates every twelve minutes (or so).
It also displays TFRs as well. Of particular interest to me, I can keep getting updated information for my destination and alternates, without touching a radio.

All in all, if you fly cross country more than a "little", I think having XM weather is a must. Combined with a quick look at Pilot MyCast on the way to the airport($9.99 a month and well worth it) and a briefing, you have good tools to avoid the number one pilot killer.

Just MHO,
 
XM Weather - Pictures

I think that XM weather is VERY handy. It is true that onboard radar is MUCH better if you are operating very close to thunderstorms, but XM sure gives you a good overall picture of weather. Knowing what is behind the weather you are skirting is very valuable information.

The big XM weather package is nice, but the lite package has the products that you would be most interested in.

Here are some photos I took while deviating around a small line of thunderstorms this summer. The flight was pretty much smooth at altitude and I was able to maintain VFR the whole way, although I am able to operate IFR if needed.

Garmin.JPG


Weather.JPG


WxPanel.JPG
 
Drew,

In one of your photos, I noticed red box markers attached to the thunderstorm cells on your GPS496. I'm guessing they show direction and speed...... I have a 396 with XM Lite and can't find these as options. How do you switch them on?
 
The red boxs and arrows, as well as the lightning bolts are part of the full XM subscription. Nice to know, but I think you can see direction of movement on a 396 with the lite package using the "animate weather" function.
 
On a recent trip West the weather was moving so rapidly that the XM info, even with frequent updates was quite deceiving and almost of no value, ended up flying the old fashioned way, by eyeball. Note that on this day the refresh rate was ruunning anywhere from 15 to 35 minutes as opposed to the usual 6-12. The weather system was moving from my left to right at 20-30 knots.

XM views suggesting all the badness to the left.
Badness_to_the_left.jpg


Badness_to_the_left_2.jpg


Views from the cockpit...

Out the left

view_to_the_left.jpg


View ahead

view_ahead_2.jpg


View to the right

view_to_the_right_1.jpg


Clearly the weather system has moved North into my flight pathe in the 31 minutes since the last update and has changed somewhat in appearance as visually the weather to my right was worse than that to my left and was clear ahead where the XM was not showing a path.
 
I suspect, based on your photos, that the weather on your right may not have even shown up with onboard radar. You must keep in mind that the XM updates may be slow or even stop at times. There is nothing better than the old mark one eyeball for weather avoidance, that is, when you are not in the clouds or on a moonless night. It is fairly common to see buildups well into the flight levels that do not show up on XM or "real" radar. I still think that XM is way better than not having it. Keep you eyes open no matter what.
 
XM USER

I have been using xm for 4 years now.:cool: you can save a bit of $ by switching to the aviator lite at any time. the other option is to turn it off then pay the $75 activation fee when you start up again.:p another usefull trick is to switch to automobile mode to see the forcast movement of a thunderstorm. :confused:you will have to zoom in to a certian range to get this info and it may only be available on the $50 subscription. that brings me to the last point. for $50 you can get the aviator or the MASTER MARINER. for the same price you can look at nautical info like bouy reports that may be still working in hurricane areas. :eek:
 
service

so the marine service has the same as the full aviator (winds, etc) plus other info??? lbb
 
more for the same $

lbgjb said:
so the marine service has the same as the full aviator (winds, etc) plus other info??? lbb
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my 496 has auto, aviation, and marine selections. with the master mariner $50 subscription you get it all. the bouy reports for the hurricanes have been fun. you would also get wave heights, and directions, water tempertures. all very helpfull if you had to ditch:D. hurricane tracks also, well check it out.
 
If your XM is not updating Nexrad every 5 minutes, you have an antenna problem or an antenna location problem. Mine almost never misses a 5 minute update, and when it does, it is because the antenna was shaded by aircraft structure.

If your antenna has a clear sky view to the south, and you are not getting updates, something is wrong with your system.

As for XM, in my view, it is the greatest advancement in aviation safety since the D-cell flashlight. I seldom leave sight of my home airport without it, and almost NEVER fly IFR without it.

Can I fly without it? absolutely, I did it for almost 30 years, but why would I? It is just like flying at night without a flashlight.

If you fly much at all, you can save enough gas with the winds aloft function to pay the subscription.

Tailwinds,
Doug Rozendaal
 
I have found that the nexrad updates seem to be slower around thunderstorms for some reason. The XM radio part still works fine around weather. I just figure that the amount of data in heavy weather areas slows down the transfer.
 
The photos I posted above were on the first leg of a 3600NM trip out West. I was using a borrowed 496. The slow (31 minute) updates were frustrating. In the past and as noted above I have always seen 6-12 minute updates.

By the time I arrived in Sedona the 496 would still pickup weather but now would not track GPS satellites. A friend suggested a "hard boot" (holding the out button when powering up). Worked like a charm GPS sats showed up and weather updates as they should be. The 496 even only took 30 seconds to find itself in Leadville Colorado after its last known fix was East of Sedona.

I am wondering if this "hard boot" would work for those having trouble picking up metars and does any of this have anything to do with some of the early apollo units no longer working?
 
Having XM Weather is the best insurance policy available.

I have used XM Weather for the past 2 years and found it to be a necessity for cross countries and IFR flying. I have the cheeper version that provides not only NEXRAD but METARs for airports. I use a Garmin 496 and by running the curser out over an airport, I get a METAR that is only 5 minutes old. As for mounting the unit after the panel is finished, I used RAM mounts in my cockpit.
dsc02130tk1.jpg
 
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