An example of bad meteorology...

[Scott Dennstaedt, PhD]

I don't usually make too big of a stink when I see an advisory or forecast go off the rails...but this is one of those that I just can't withhold a comment...

Earlier today I noticed a center weather advisory (CWA) issued by the Jax CWSU for severe ice between FL380 and 410.  Huh?  What?  Must be an error. Even the AWC parser didn't pick up the altitudes for this.   

That CWA was likely issued upon receipt of this urgent PIREP from an Embraer EMB-505 Phenom 300.

Moreover, there was also a convective SIGMET in the area that implies severe ice by definition.  You don't need both of these. Lack of coordination between the CWSU and the AWC.  

At a temperature approaching -60°C, it's not likely a supercooled liquid water (airframe icing) issue even with convection nearby.

Given the temps at that altitude it's more likely high ice water content. The report was made not far outside of the strongest echoes, rather than right within them. Ugh! 

 

[Ibra]

The PIREP says -47C on encounter (not -60C), beyond rime ice range but not impossible?

Edited December 15, 2022 by Ibra

[Scott Dennstaedt, PhD]

3 hours ago, Ibra said:

The PIREP says -47C on encounter (not -60C), beyond rime ice range but not impossible?

The temperature in the area at FL410 were nearly -60°C.  The PIREP may have been reporting the total air temperature, not the static air temperature.  Once the static air temperature gets to be -40°C or colder, liquid water cannot exist.  No matter how pristine the drop is, it will freeze.  Supercooled liquid water is very rare below -35°C. This is a clear case of high ice water content and not supercooled liquid water.  So that begs the question...what is icing from an advisory perspective.  Supercooled liquid water? Induction? Carburetor?  High ice water content?  There are no advisories issued for the latter three.