Any good way to tell cloud tops?

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Code90

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Code90
I'm still a low time IFR pilot. Always looking for advice.
Does anyone know a good way to tell cloud top levels? I'm am occasionally trying to decide if I should file for 4000, 6000 or 10000. On cloudy days, it's nice to get above the clouds. I can see some of the high tops of big CB shown on Foreflight. I'm not interested in getting near any of that. What I would like to find is the tops of light clouds on days / places I would actually fly.
 
On the ground the best bet is the skew-t. I can't really give the skew-t justice in one post but if you do some searching on PoA and Google you'll learn all about it. You can see where various layers start and end based on the temp/dewpoint meeting and spreading again at different altitudes. It is, however, a model based on observations so it's not perfect but it's surprisingly good.

In flight, your best bet, is to just ask ATC if they have any reports for tops. 99% of the time they'll know or they'll ask a plane that just climbed through it. Easy enough to amend your altitude.
 
For flight planning the Area Forecast as a wider general idea...

http://www.aviationweather.gov/areafcst

CNTRL CA
CSTL SXNS...
CSTLN..SCT020 SCT CI. S HLF BECMG 0608 BKN010 TOP 020. OTLK...N HLF VFR S HLF MVFR CIG 17Z VFR.
INLAND..SCT040 SCT CI. BECMG 1012 BKN020 TOP 030. OTLK...IFR CIG 17Z VFR.
SAN JOAQUIN VLY...SCT060 SCT CI. 08Z S HLF BKN060 TOP 120. 11Z N HLF VIS 3-5SM BR. OTLK...N HLF IFR CIG 17Z VFR ELSW VFR.
SRN SIERNEV...SCT150 SCT CI. OTLK...VFR.
 
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Shawn said:
For flight planning the Area Forecast as a wider general idea...

http://www.aviationweather.gov/areafcst

CNTRL CA
CSTL SXNS...
CSTLN..SCT020 SCT CI. S HLF BECMG 0608 BKN010 TOP 020. OTLK...N HLF VFR S HLF MVFR CIG 17Z VFR.
INLAND..SCT040 SCT CI. BECMG 1012 BKN020 TOP 030. OTLK...IFR CIG 17Z VFR.
SAN JOAQUIN VLY...SCT060 SCT CI. 08Z S HLF BKN060 TOP 120. 11Z N HLF VIS 3-5SM BR. OTLK...N HLF IFR CIG 17Z VFR ELSW VFR.
SRN SIERNEV...SCT150 SCT CI. OTLK...VFR.
Click to expand...


But it gives the highest tops, so if thunderstorms are forecasted, even if scattered, you tops will be FL 410 or higher
 
I have the Skewt Pro on my Ipad. It has been well worth the $10, especially in Michigan winter weather. Helps confirm a go no go flight.

Also while in the air, just ask ATC if they have any Pireps for your area.
 
WOW - Thanks for the tip. It is Great!!

So much faster than using a web browser to go to their website.

MyassisDragon said:
I have the Skewt Pro on my Ipad. It has been well worth the $10, especially in Michigan winter weather. Helps confirm a go no go flight.

Also while in the air, just ask ATC if they have any Pireps for your area.
Click to expand...
 
MyassisDragon said:
I have the Skewt Pro on my Ipad. It has been well worth the $10, especially in Michigan winter weather. Helps confirm a go no go flight.

Also while in the air, just ask ATC if they have any Pireps for your area.
Click to expand...

Skew-T's don't cost $10 unless they are wrapped in some fancy unnecessary interface.

http://rucsoundings.noaa.gov
 
I am pretty much an amateur IFR Pilot. I just don't normally have access to adequate equipment for actual IFR out west. Nor do I often have much reason to travel anywhere.

However for local training flights I often use the Web cam at the Local Ski area. If it is in the sun I know cloud tops are below 7500 feet.

If that doesnt work I often call the Boise Tower and ask if they have had any recent cloud tops and icing report. Usually I then hear something like this in the background.
Hey Joe, have you had any tops reports?

No, hang on a second, Horzion 2xx, can I get a tops report? We just went in the clear at 8000, Horizon 2xx.

Brian
 
1. Area forecasts, as noted. Easy to get, but as they cover a very wide area they're not always accurate.
2. PIREPs, as noted. Also easy to get, but sadly all too rare. You might be able to call your nearest TRACON and have them ask for a tops report from a departing or arriving aircraft, though.
3. Skew-T diagrams (either via http://rucsoundings.noaa.gov/ or the SkewTLogPro iOS app) - Look at where temp and dewpoint diverge significantly and you can determine layers and/or tops. This is the best tool of them all.
4. VAD Wind Profiler. http://vortex.plymouth.edu/gen_lnids.cgi?pl=nvw&cu=1&loop=no&ident=CXX Pick a radar site and where there's visible moisture you'll see winds aloft data. Where it says "ND" (No Data), there was no visible moisture at that altitude at that time. Note that since this is restricted to radar sites at specific times it may be a bit "mushy" but it does give you an actual measurement to compare with the SkewT's. If they agree, you've got a very high probability that's where the tops are.
 
MAKG1 said:
Skew-T's don't cost $10 unless they are wrapped in some fancy unnecessary interface.

http://rucsoundings.noaa.gov
Click to expand...

I actually prefer the app to the site - It'll grab current location if you want, and I have it set to grab the plots for the past 6 hours and next 18 hours. Then, I can just swipe between them to see how conditions are changing, and it loads WAY faster than if I were to try and open 24 browser tabs to do the same thing.

Like the other poster said, well worth the ten bucks.
 
MAKG1 said:
Skew-T's don't cost $10 unless they are wrapped in some fancy unnecessary interface.

http://rucsoundings.noaa.gov
Click to expand...
The issue for a while was that one could not access the "live" Skew-T with a tablet since it was Java based. That fortunately ended about a year ago when they included a JavaScript version.

More than meets my needs.
 
teejayevans said:
But it gives the highest tops, so if thunderstorms are forecasted, even if scattered, you tops will be FL 410 or higher
Click to expand...
While the tops listed in the area forecast will indeed be the highest layer if multiple layers exist and in any case unless there's a huge stratus layer the tops will not be the same everywhere, those tops will not include TRW cells unless specifically stated that way. That said, IME the tops are rarely consistent with the forecast. PIREPS and Skew-T are far more accurate and reliable.
 
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jesse said:
On the ground the best bet is the skew-t. I can't really give the skew-t justice in one post but if you do some searching on PoA and Google you'll learn all about it. You can see where various layers start and end based on the temp/dewpoint meeting and spreading again at different altitudes. It is, however, a model based on observations so it's not perfect but it's surprisingly good.

In flight, your best bet, is to just ask ATC if they have any reports for tops. 99% of the time they'll know or they'll ask a plane that just climbed through it. Easy enough to amend your altitude.
Click to expand...

Those "observations" are taken by rawinsonde, so they are a little better than "surprisingly good". Not all of them are atmospheric samples though, some are based on predictions based on supercomputer number crunching of aggregate data. ScottD discusses them in detail on his site.
 
Jaybird180 said:
Those "observations" are taken by rawinsonde, so they are a little better than "surprisingly good". Not all of them are atmospheric samples though, some are based on predictions based on supercomputer number crunching of aggregate data. ScottD discusses them in detail on his site.
Click to expand...

Sure, but you're still looking at data from a model, since the observations aren't made at every single point in the sky. Like I said it's good but it's a model. There isn't a weather ballon above you at every moment you're looking so it's possible for it to be wrong but it's quite rare for the model to be off that much. I wouldn't bet my life on finding a tiny layer of no ice just because the skew-t says there is a tiny layer is what I'm getting at.
 
Jaybird180 said:
Those "observations" are taken by rawinsonde, so they are a little better than "surprisingly good". Not all of them are atmospheric samples though, some are based on predictions based on supercomputer number crunching of aggregate data. ScottD discusses them in detail on his site.
Click to expand...
RAOBs can be plotted on a Skew-T but only for the 100 or so locations that launch the balloons, and only for the time the balloons are launched (00 and 12 Zulu). The computer weather model outputs provide similar data for up to 18 hours into the future and for a much larger number of locations (20 or 40 km grid).
 
Code90 said:
I'm still a low time IFR pilot. Always looking for advice.
Does anyone know a good way to tell cloud top levels? I'm am occasionally trying to decide if I should file for 4000, 6000 or 10000. On cloudy days, it's nice to get above the clouds. I can see some of the high tops of big CB shown on Foreflight. I'm not interested in getting near any of that. What I would like to find is the tops of light clouds on days / places I would actually fly.
Click to expand...

Been using this for over 300hrs now:

http://rucsoundings.noaa.gov/gifs/
 
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