Sylmar Hang Gliding Association

Plenty of people are asking about the upcoming week. Although it's heating, up the Skew-T chart tells a pretty
good story on what you can expect of the day especially on the front range of the mountains. Start using the Skew-T
charts to validate the BlipMap and BlipSpot. You's find them near the bottom of the page on my Weather Site




This graphic shows why today (May 7, 2006) basically sucked. BlipMaps are nice but pilots need to look at
all the sources available when making the choice for "good" flying potential. Strong low inversion coupled
with a "weak" off shore flow.

The upcoming week doesn't look all that great unless you go inland and even then it's not "booming" yet.
Looks like we missed the spring convergence (more like it never really showed up).

Would be great if you would have a clinic on "How to Read the Data and Predict the Flying Conditions". If you have any interest in doing so.

There are so many sources for infomation, but they need to be deciphered, like runes or something.

Maybe there would be an opportunity at the next festival (or whatever) at Kagel.

I often guess wrong but do not really know why. Would be nice to get it right more often.

JBBenson wrote:I often guess wrong but do not really know why. Would be nice to get it right more often.

Did this explaination of the Skew-T help any or did it bring up more questions than answers?

Also if you compare today's Skew chart with this one you would see the day looked even worse than yesterday.

If you compare that with the BlipSpot, you'll see some corresponding data that validates the Skew or vice-a-versa (heights today forecast to be 3800 - 4300). The BlipSpot was probably too optomistic today as the high temp was only 74 and the Spot forecasted 78. Tomorrow's data doesn't look any better.

But as a better illustration on how the Skew-T helps map out the atmosphere, look at the comparison between the Miramar sounding and the Las Vegas sounding. Vegas has no ground inversion and the two other soundings (Vandanberg and Miramar), both show a STRONG inversion around 2500 - 3000 (lower than yesterday). For me it shows clearly that the better flying at the moment would be in the desert, far away from the coast.

I guess it starts to make some sense. Which sounding is more accurate for local (i.e. Sylmar) conditions, generally? Or is it an amalgamation of both L.V. and Miramar?

How do the numbers (on the left) corresponding to altitudes? And why do they go down as we go up?

Yeah,
I got the part about it sucking rocks on Sunday. Clear as the sky today, Chip.

I think the suggestion of a clinic is good. Better yet, just post your call daily. You could make it easy for us; develop a suck-o-meter with a scale of 1 to 10.

1 - Get up and go somewhere.

5 - Set up time (topless) ~ flight time

10 - No point in setting up; get out the beer instead.

Just kidding. I know your time is more precious than that. Clinic is a good idea. You know, "teach a man to fish..."

Basically I'm not shy about a clinic, but I know I'm no expert either so I do not want to pass myself off as one.

In answer to your questions:

First I use both the Miramar and Vandenberg soundings to get some idea of the atmosphere near the coast. If there are big differences between Vandenberg and Miramar I will usually side more with the Miramar sounding unless a front is approaching, then the Vandenberg sounding would be more usable. If Miramar and Vandenberg are looking good I will look at the Las Vegas sounding to see how good the desert is looking. All three looking good indicates great conditions in the entire southland. So unless the wind is howling, go out and have fun.

Any other Skew-T charts (like the ones here) other than these three are interpolated, but they are good estimates.

The numbers on the left are in millibars (atmospheric air pressure is often given in millibars where "standard" sea level pressure is defined as 1013.25 mbar (hPa). They represent the atmospheric pressure throughout the atmosphere. As the height increases the pressure decreases. 900 = 3,000', 800 = 6,000', 650 = 12,000' and 500 = 18,000'. No need to go any higher because we are not allowed above 17,999'.

The red line is the temperature profile as the balloon rises. Temperature scale is on the bottom. Higher temps are on the right and decreases toward the left. The green line is the dew point. When the red line and green line are near each other clouds are likely to form. You'll usually see this on the Vandenberg sounding first as a front approaches.

I've edited the LV sounding from today to show you a very good lapse rate as shown on the sounding. This won't be typical of Sylmar, but if you ever see it look like this make sure your calling in sick on that day.



The BlipMap RUC (Rapid Update Cycle model) for 5/9/2006 shows the predicted height in agreement (somewhat) with the Skew-T.