Les

[lenny]

Hey John

Question for ya. I remember a thread about ideal temps for LES (18-24.) Looks like this week we are at the prime temps for LES and even wind direction but I see little snow in the forecast. What other element might we be missing to get LES?


Leo the Lop,,,aka Lenny

 

[jd]

Hi Lenny.

There is quite a bit more actually, but the main thing is the stability (or really instability) of the atmosphere and then the wind direction. For most things that happen in the world of weather, the things that are most important are not what conditions are like here at the surface, but rather what things are like from around 1000 feet up to around 20,000 feet up. In the case of LES, it's from around 1000 feet up to around 10-12 thousand feet up.

This week, the atmosphere looks to be just relatively unstable, but just enough to make it spit flakes for most of the week and not dump.

Hang in there, it will dump, always does and things would not have to change too dramatically to get it snowing at a better clip, so perhaps we'll be surprised by some of the activity this week.

-John

 

[frosty]

With the current LES going on up there, I went to the NOAA site to look at the radar and all it showing is ground clutter near Marquette. Does LES show up on radar or does it not have the reflectivity of a regular storm has for radar? Does the water vapor show LES better?

 

[jd]

frosty-

Many times the clouds that produce the lake effect snow happen in the lower elevations of the atmosphere (below 10-15k feet). Because the earths surface is curved, as you get more than 45-65 miles away from the radar, the beam is already looking higher up than 10-15k feet, so the radar is actually overshooting the clouds that produce the LES. It is pretty rare to see LES happen over the Keweenaw and in the few times you do see it, it is probably coming down at the rate of 3-5"/hr!

-John

 

[frosty]

Would have never thought about that curvature thingy! I thought the world was flat.

Then we need those clouds to grow up to 15k feet, we need 3-5"/hr!

Thanks John