Icing season arrives

azure

azure

Final Approach
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azure
With the arrival of a closed upper low with widespread low clouds, and the toning down of any threat of convective activity in the forecast discussion overnight, I was hoping to get out and shoot some approaches in actual today.

Then I turned on the airmets layer in SkyVector and noticed an airmet for icing between 7000 and 12,000 reaching as far north (!!) as MPV (i.e., it's mainly south of MPV). Freezing level as low as 6500 with multiple freezing levels between 7000 and 9000 across the area. Very bad combination.

The G-AIRMET graphics on ADDS confirm the airmets but not the freezing levels, which appear to be 12,000 or above over the whole area. Only FZLVLs below 8000 are over NY south of Lake Ontario, and westward into the Lakes region.

Also, the Skew-T for KMPV contradicts this, showing a freezing level well above 10,000 all afternoon. Ditto for KLEB, which is inside the airmet region.

With contradictory info like this I've canceled my plans to fly, but if anyone has anything to add that might clarify the situation, it would be appreciated.
 
Did you check for any pireps on your route?
 
frfly172 said:
Did you check for any pireps on your route?
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Well my "route" would be very limited - a local IFR to shoot approaches. But there are none over the entire area. A couple of negative pireps over PA, some light rime at 9000 in NE OH (where ADDS shows the FZLVL under 8000).

Doesn't mean anything, of course, might be no one has been flying at those altitudes since the airmet was issued. Absence of pireps in a lightly traveled area like this doesn't reassure me at all.
 
TangoWhiskey said:
Local IFR for approaches... You can stay below 6000, no?!
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No. I would need one of the approaches to 17 to get back in, and I'm typically asked to climb to 6400 going up toward TJAYS or HUSAV. I'm pretty sure that's the MVA up there.
 
Practically all of the info I have says the freezing level in my area is over 10,000 and forecast to remain that way until tonight. I'm really not sure why that icing airmet is out there but it's also consistently shown on every source I have, including ForeFlight.

ADDS has now pushed the airmet back to 21Z in their G-AIRMET display. That still seems very early based on the lowest freezing level graphics, which show no FZLVL below 9000 over the whole area affected by the airmet.

I will be really ticked if it turns out the airmet was an error. I do notice that it's replaced by another airmet over a larger area from 9000 as of 00Z.
 
In my experience Airmets tend to be very "loose" in their scope. There are entire threads devoted to whether or not flying into an Airmet Zulu area is considered flying into known icing, but I stay out altogether (and usually give myself an additional 1 - 2k feet of cushion just to be sure - a 172 is nothing to get caught in the ice in).
 
I realized that this particular airmet didn't make sense, so I went flying. The main issue turned out to be a line of heavy precip about 30 miles west, moving very slowly but moving. I only got in two approaches before it got too close for comfort and called it a day (other consideration: the FBO closes up at 5pm sharp and I sure didn't want to get stuck outside the hangar tonight).

One thing I learned is that although the MVA was indeed over 6000, the feeder route from MPV to TJAYS for the ILS 17 into KMPV is in the 480 database, has a charted altitude of 5900, and they were able to clear me for it even though they lost me on radar about 10 miles north of the VOR. The OAT up there was 9C, confirming my hunch that there was no risk of icing (outside of a thunderstorm, of course).

It was good practice, the best I've had here since last October. My only complaint is that I needed one more approach to budge my currency. ;)
 
azure said:
Practically all of the info I have says the freezing level in my area is over 10,000 and forecast to remain that way until tonight. I'm really not sure why that icing airmet is out there but it's also consistently shown on every source I have, including ForeFlight.

ADDS has now pushed the airmet back to 21Z in their G-AIRMET display. That still seems very early based on the lowest freezing level graphics, which show no FZLVL below 9000 over the whole area affected by the airmet.

I will be really ticked if it turns out the airmet was an error. I do notice that it's replaced by another airmet over a larger area from 9000 as of 00Z.
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Its called CYA. Better to say there is a chance of icing and you not go than not mention icing and you go.
 
Zeldman said:
Its called CYA. Better to say there is a chance of icing and you not go than not mention icing and you go.
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All airmets are CYA by that standard. Of course CYA explains why they're looser than seems necessary, but this one was totally off the wall, not justified by any forecast available to pilots, including the Skew-T. Issued at 1445Z, immediately active, even though the freezing level wasn't forecast to fall below 9000 anywhere east of the Adirondacks/Catskills/Poconos until 12 hours later.

I think it was a simple mistake, unless there was a different forecast model that predicted quicker motion of the low and associated air temperatures.
 
I've hit icing twice in my flying career (mostly because I avoid potential conditions like the plague). Once was early October coming out of coastal north carolina. I wasn't even thinking about it seeing how nice the weather had been (we had been out on a boat in shirt sleaves) but up in the air we were in the right levels.

The other time was in August but we were up much higher (16000 if I recall).
 
azure said:
One thing I learned is that although the MVA was indeed over 6000, the feeder route from MPV to TJAYS for the ILS 17 into KMPV is in the 480 database, has a charted altitude of 5900,
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26.8nm feeder!! Whew!
 
Where is a good source for skew-t and log-p charts? Preferably by airport ID
 
Actually I am looking forward to IMC conditions with a little icing again. Keeps me on my toes. Especially at night over mountainous terrain.

Seems like when the plane starts picking up ice the heater starts working better. At least I do start sweating....
 
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