• After witnessing the continued decrease of involvement in the SpotterNetwork staff in serving SN members with troubleshooting issues recently, I have unilaterally decided to terminate the relationship between SpotterNetwork's support and Stormtrack. I have witnessed multiple users unable to receive support weeks after initiating help threads on the forum. I find this lack of response from SpotterNetwork officials disappointing and a failure to hold up their end of the agreement that was made years ago, before I took over management of this site. In my opinion, having Stormtrack users sit and wait for so long to receive help on SpotterNetwork issues on the Stormtrack forums reflects poorly not only on SpotterNetwork, but on Stormtrack and (by association) me as well. Since the issue has not been satisfactorily addressed, I no longer wish for the Stormtrack forum to be associated with SpotterNetwork.

    I apologize to those who continue to have issues with the service and continue to see their issues left unaddressed. Please understand that the connection between ST and SN was put in place long before I had any say over it. But now that I am the "captain of this ship," it is within my right (nay, duty) to make adjustments as I see necessary. Ending this relationship is such an adjustment.

    For those who continue to need help, I recommend navigating a web browswer to SpotterNetwork's About page, and seeking the individuals listed on that page for all further inquiries about SpotterNetwork.

    From this moment forward, the SpotterNetwork sub-forum has been hidden/deleted and there will be no assurance that any SpotterNetwork issues brought up in any of Stormtrack's other sub-forums will be addressed. Do not rely on Stormtrack for help with SpotterNetwork issues.

    Sincerely, Jeff D.

Thickness levels and surface temperatures

Rocky Rascovich

EF4
Joined
Jul 17, 2004
Messages
381
Location
Piedmont, OK
I guess everyone is entitled to one dumb question every now and then. The NAM especially has been overdoing the thicknesses on the warm side with this ice event here in Okla. By 18Z today, thicknesses are progged to be near 550 over cntrl OK. Current temps here at the farm as of 0915 are aprox. 23F. I doubt we'll be much above 27F for today.

The question is.. isn't 540 the magic number for ice/snow? Does that mean 32 deg. at the surface or at a certain level aloft? I always thought 540 was the freezing point at the surface.

You can PM me privately about this question. Thanks!
Rocky&family
 
Rocky,

That's not a dumb question at all as the 540 line can be very deceptive without knowing a little more about it.

The 540 thickness is a "rule of thumb" used by forecasters east of the Rockies to estimate whether or not the entire column of air between 1000-500 mb is approximately below freezing (including, but not limited to the surface). This works because the thickness of that layer is a function of the total temperature profile in that layer (warmer = thicker), and 540 just happens to be the thickness that "typically" means the whole profile is below freezing (thereby yielding snow as the dominant precipitation type). However, it's important to note that this is an approximation that is dependent on local altitude and climate, and often does not hold true in reality. That said, it's a good place to start when determining possible precip types.

If you would like more detail, just reply. I'll be happy to post a couple of example soundings showing how this looks in real life when I get the chance...unless someone else beats me to it. ;)
 
If the cold air is shallow and warm air is rising above it (over running) then the cold air is trapped at the surface, thickness is higher then 540 due to the warm air aloft and you have an ice scenario. 540 can be the snow-rain line and not the ice line.
 
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