Abrupt Weather Changes

[Mark Hargrove]

I had an interesting experience on a cross-country from KCRQ to KTOA last night (I was flying with the time set to 'day'). Weather was 8000 broken with 20 miles visibilty out of KCRQ, and was showing similar at KTOA just before departure. I was using 4500 for my cruise altitude. I picked up flight following just west of the OCN VOR and was motoring along just fine for quite a while. Just beyond KSNA, I asked for a brief frequency change to listen to the KTOA ATIS, which was granted. ATIS reports 7900 overcast in light rain. "Hmm," I think, "that's interesting."

As I switch back to SoCal, the latest METAR gets updated into FSX and *BAM* -- I am in the clouds (and it is indeed raining. And it is suddenly bumpy as heck). "Hmm", I think again, "well now that's really interesting." I can see the ground (the ocean surface, actually), so I'm not in the middle of the cloud layer, but I'm not legal by any stretch of the imagination either. I immediately called SoCal and told them I was going to descend to 3000' to avoid the weather, which they acknowledged. We also had a brief exchange about the numbers at KTOA, both agreeing they were landing Rwy 29.

After descending to 3000', I'm nearly at Long Beach harbor and finally clear of clouds again. Squinting a little, I can make out Torrance airport, so I let SoCal know I'm going to descend to 2000' and have the field in sight. I'm also tracking the localizer inbound, so my positional confidence is very high. I get handed over to Torrance tower, and right as I'm talking to them the turbulence ratchets up a notch.

It's now gone from "interesting" to "this really sucks". The suckiness only gets worse: Torrance tells me to make left traffic for Rwy 11, since the wind is now 100@9kts. Tower kindly offers to let me have Rwy 29 if I really want it with 9kt tailwind. I tell them thanks, but I'll enter downwind and land Rwy 11. They acknowledge and ask me to report turning base. I'm busy as hell for a minute or so verifying the TPA, getting flaps out to slow down, and trying to figure out if I can just widen out a bit to directly enter the downwind for Rwy 11, or if I have to swing way out and enter at on a 45 -- I just couldn't remember the proper procedure. Getting bounced around made the decision easy: I entered the downwind directly (I still don't know if that was OK or not, but ATC didn't complain). Unfortunately, I'd been too busy to acknowledge the "report turning base" call before they called me back to remind me to do so. I did acknowledge the second time around, eventually called my base turn and was cleared to land. Although my approach was a bit sloppy (I turned base a little too soon, and was high), the landing was uneventful.

In real life, weather can't change that abruptly -- you can't go from 20nm visibility in VFR conditions to IMC in a split second without having some clue that things are deteriorating. But you CAN, apparently, have that happen in FSX after METAR update. What's the right thing to do under these circumstances? If I'd been flying at 6500 instead of 4500, I'd have been in solid IMC only seconds after having been in legal VFR conditions with good visibility.

-M.

[Alex Stjepanovic]

In real life, weather can't change that abruptly -- you can't go from 20nm visibility in VFR conditions to IMC in a split second without having some clue that things are deteriorating.

Try living in a place with an appropriate enough of a climate, and check for yourself

On numerous occasions, I've witnessed Irish weather changes, where it would go from anywhere from two to six(ish) different states in a matter of about a minute or so. It's not as drastic as what the simulators pull on us, but darn close.

[Keith Smith]

This is why X-Plane 10 has such an advantage with its native ability to load multiple concurrency weather systems. I have heard that Opus is a great add-on for FSX that apparently supports multiple weather systems, too (not just pretty new cloud textures) if I'm not mistaken.

In terms of what to do, try to get out of it (higher, lower), or pick up a clearance. Inadvertent flight into IMC does happen....actually happened to me roughly 2yrs ago: http://www.youtube.com/watch?v=vl_dORZUyTA (3 min mark). There was a super thin, semi translucent layer ahead of us, with an overcast layer above that. My eyes perceived it has haze with overcast on top. During the VFR climb, the ground suddenly faded away and vis dropped, then second later, we were on top..and ahead of us, the 'haze' was turning into a solid layer (you'll see it on the video). It was totally unexpected, at least to my eye at the time. I've since learned to look out for those situations.

If you know what the new weather is and you can safely descend below it, I wouldn't sweat it too much (in the sim). Only if you're now stuck in it would I convert over to IFR. The call would be simple, "[callsign] inadvertently entered IMC, request clearance to [destination]."

[Mark Hargrove]

I'm actually running the OpusFSX plugin, and it is amazing -- but apparently still allows this "instant change" to the weather to happen when a METAR update occurs.

So it sounds like I did the right thing by just descending under the cloud layer. I did briefly toy with the idea of just filing IFR, but 2 minutes after the weather appeared I was safely under it.