Saul Trabal
EF4
What are the chances of thundersnow with this upcoming snowstorm? Can this be forecast? If so, how?
-
Happy birthday to Stormtrack! The newsletter was founded on this day in 1977, which makes the community 47 years old this year! The community has evolved dramatically from a small group of enthusiasts (a combination of "yahoos" and some folks who were beginning to try to understand how tornadoes form and why) as a paper-based newsletter to the online forum today with a few thousand members.
Remember that we are still planning to assemble some kind of 50th anniversary anthology for 2027. The hope is to include short-form essays on a variety of topics spearheaded by those most involved, chaser profiles, a timeline of the forum, and other highlights. Please consider contributing some material, whether it be merely your own story of storm chasing or otherwise.
Possibility For Thundersnow With This Snowstorm?
- Thread starter Saul Trabal
- Start date
Chris Nuttall
EF5
We need one of two things to get thundersnow. Instability or strong UVVs. Thundersnow is convective precip. So, basically, it's the same type of ingredients that go into generating any convective storm with the obvious addition of cold enough surface temps to get snow at the surface.
If you want to forecast thundersnow, look for any areas of CAPE..both elevated (for elevated convection) and surface-based. Also, look for areas of strong upward motion. So, look at some forecast soundings. I haven't looked at any soundings myself, but I don't think we are going to have much in the way of CAPE. However, if things verify, there could be a chance of some decent dynamic lifting. So, the chances of thundersnow are there probably around the OK/KS border where the heaviest snow will be.
I hope that's right. My winter weather expertise is somewhat limited except to forecast precip amounts and placement. I'm much better at that.
If you want to forecast thundersnow, look for any areas of CAPE..both elevated (for elevated convection) and surface-based. Also, look for areas of strong upward motion. So, look at some forecast soundings. I haven't looked at any soundings myself, but I don't think we are going to have much in the way of CAPE. However, if things verify, there could be a chance of some decent dynamic lifting. So, the chances of thundersnow are there probably around the OK/KS border where the heaviest snow will be.
I hope that's right. My winter weather expertise is somewhat limited except to forecast precip amounts and placement. I'm much better at that.
Robert Dewey
EF5
Actually, looking at CAPE probably won't help much unless you are calculating lake induced CAPE for a lake-effect event.
You really need to look at cross sections and time-height sections to get a better handle on things. There are three main types of instability...
Absolute instability - Theta decreases with height
Potential instability - Theta-e decreases with height
Conditional instability - Saturated theta-e decreases with height
Then, for "CSI", you have Conditional Symmetric Instability - which adds the geostrophic momentum surface into the mix. With that, all you do is take the "parcel" along the geo. momentum surface, and if the saturated theta-e decreases along that surface, it's potentially unstable.
Of course, you also need some lifting, or that instability is useless.
You really need to look at cross sections and time-height sections to get a better handle on things. There are three main types of instability...
Absolute instability - Theta decreases with height
Potential instability - Theta-e decreases with height
Conditional instability - Saturated theta-e decreases with height
Then, for "CSI", you have Conditional Symmetric Instability - which adds the geostrophic momentum surface into the mix. With that, all you do is take the "parcel" along the geo. momentum surface, and if the saturated theta-e decreases along that surface, it's potentially unstable.
Of course, you also need some lifting, or that instability is useless.
mikegeukes
EF5
Move to thundersnow with cg Delete please. THanks
Mike
Mike
Mike Johnston
EF5
Saul, did you have some kind of premonition of this event? Goodness, not only thundersnow, but CG reports and descriptions of orange balls of lightening from passengers in that airplane. Given that you were asking a question of whether and how this could be forecasted, I take it your post wasn't a forecast, but something must have prompted you to consider this topic for this particular storm?
Saul Trabal
EF4
Nah-I don't have any cool super powers.
Sorry to dissapoint.
