Severe Cold and XM Weather Cloud Depiction

[Jay Honeck[_2_]]

Our last two flights have taken place in severe cold -- zero Fahrenheit and
below.

On both flights we noticed that XM satellite weather on our Garmin 496 was
inaccurately depicting cloud cover in our area. In fact, it was showing a
solid overcast over a large geographic area that was actually severe clear.

Has anyone seen this? Can severely cold air spoof the satellite into
"seeing" cloud cover?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Bertie the Bunyip[_24_]]

"Jay Honeck" > wrote in
news:C7Ppj.16050$9j6.7847@attbi_s22:

> Our last two flights have taken place in severe cold -- zero
> Fahrenheit and below.
>
> On both flights we noticed that XM satellite weather on our Garmin 496
> was inaccurately depicting cloud cover in our area. In fact, it was
> showing a solid overcast over a large geographic area that was
> actually severe clear.
>
> Has anyone seen this? Can severely cold air spoof the satellite into
> "seeing" cloud cover?

It could make one cry.


Bertie

[Morgans[_2_]]

"Jay Honeck" > wrote

> Has anyone seen this? Can severely cold air spoof the satellite into
> "seeing" cloud cover?

Sure. It thinks the cold air is cold cloud tops.
--
Jim in NC

[[email protected]]

On Feb 4, 6:39*pm, "Jay Honeck" > wrote:
> Our last two flights have taken place in severe cold -- zero Fahrenheit and
> below.
>
> On both flights we noticed that XM satellite weather on our Garmin 496 was
> inaccurately depicting cloud cover in our area. *In fact, it was showing a
> solid overcast over a large geographic area that was actually severe clear..
>
> Has anyone seen this? *Can severely cold air spoof the satellite into
> "seeing" cloud cover?
> --
> Jay Honeck
> Iowa City, IA
> Pathfinder N56993www.AlexisParkInn.com
> "Your Aviation Destination"

Yup.. Happens all the time here in the "Hole". An IR satellite pic is
looking for temp differential and the cold air fakes out the camera. A
visible satellite pic usually gives a correct reading, but only during
the light of the day. YMMV

Ben.
Jackson Hole Wy

[Jay Honeck[_2_]]

> Sure. It thinks the cold air is cold cloud tops.

Interesting. I presumed that the satellite pics on the Garmin were taken
using visible light, not infrared.

This certainly makes the product less useful for weather avoidance.
Luckily, it's rarely that cold when we fly.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Blueskies]

"Jay Honeck" > wrote in message news:Kajqj.18280$yE1.4264@attbi_s21...
>> Sure. It thinks the cold air is cold cloud tops.
>
> Interesting. I presumed that the satellite pics on the Garmin were taken
> using visible light, not infrared.
>
> This certainly makes the product less useful for weather avoidance.
> Luckily, it's rarely that cold when we fly.
> --
> Jay Honeck
> Iowa City, IA
> Pathfinder N56993
> www.AlexisParkInn.com
> "Your Aviation Destination"
>



Wasn't this whole subject discussed at length last year?

[Gig 601XL Builder[_2_]]

Blueskies wrote:
> "Jay Honeck" > wrote in message
> news:Kajqj.18280$yE1.4264@attbi_s21...
>>> Sure. It thinks the cold air is cold cloud tops.
>>
>> Interesting. I presumed that the satellite pics on the Garmin were
>> taken using visible light, not infrared.
>>
>> This certainly makes the product less useful for weather avoidance.
>> Luckily, it's rarely that cold when we fly.
>> --
>> Jay Honeck
>> Iowa City, IA
>> Pathfinder N56993
>> www.AlexisParkInn.com
>> "Your Aviation Destination"
>
>
>
> Wasn't this whole subject discussed at length last year?
>
>


Probably but here is what the XM site says about its satellite mosaic.

"Infrared composite images of cloud taken by geostationary weather
satellites providing eight levels of cloud cover and can be presented in
5,000 foot increments.

Data Broadcast Frequency: 15 minutes"

[Jay Honeck[_2_]]

> Wasn't this whole subject discussed at length last year?

Possibly. However, last winter was so mild that I apparently never noticed
the phenomenon on my (then new to me) 496.

This winter -- the harshest in decades -- has reduced our flying to furtive
trips around the pattern whenever the storms let up. We've received over
20" of new snow in the last few days...and another deep freeze is predicted.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Bethhher.]

"Jay Honeck" > wrote in
news:Y1Hqj.19871$yE1.18669@attbi_s21:

>> Wasn't this whole subject discussed at length last year?
>
> Possibly. However, last winter was so mild that I apparently never
> noticed the phenomenon on my (then new to me) 496.
>
> This winter -- the harshest in decades -- has reduced our flying to
> furtive trips around the pattern whenever the storms let up. We've
> received over 20" of new snow in the last few days...and another deep
> freeze is predicted.

Awww, poor old Jai.



Anyhtng about airplnaes in this?

I don't see anything!





Berteeee.