Research Regarding Synoptic Scale Winter Storms And Precipitation Structures in the Deformation Bands/TROWAL Regions

[baroclinic_instability]

I had heard of it before but never really read into it much. The research looks very interesting though. Sounds like there will be quite a bit of peer reviewed articles coming soon.

PLOWS Scientific Goals:

"In the course of this PLOWS we will address the following questions: 1) What are the predominant spatial patterns of organized precipitation substructures, such as bands and generating cells, in these quadrants and how do they evolve? 2) How do frontal scale systems above and within the boundary layer such as warm fronts,, cold fronts aloft, and occluded fronts relate to these precipitation substructures? 3) What are the thermodynamic and kinematic structures of these frontal systems including the distribution of moisture and vertical motion? 4) What instabilities and types of mesoscale forcing (e.g., moist CSI, moist frontogenesis, gravity waves, and elevated upright convection) control the generation and evolution of precipitation substructures? 5) How do microphysical processes vary between the different precipitation substructures and what are the consequences? 6) Is instability triggered in ice-saturated ascent critical in some of these instances and is it through the release of the latent heat of deposition that instabilities can persist?"

https://www2.ucar.ed...f-winter-storms

"Each streamer is about 1.3 miles (2 kilometers) tall and anywhere from a half-mile to a few miles wide. That’s about the size of an ordinary cumulus cloud you might see in midsummer, when sunshine heats the ground and columns of warm, moist air rise (a process called convection). In this case, however, it’s December, and the clouds are at altitudes where the air is typically colder than –22°F (30°C), so the pockets of convection came as more of a surprise.Rauber and his collaborators aren’t yet sure what is driving the apparent cloud-top instability. However, it appears to be different from other forms of instability long associated with winter storms. It’s also surprisingly common, says Rauber: “These features are ubiquitous. We saw them in almost every case.”

Preliminary results suggest that the broad field of snow falling through a winter storm’s comma cloud originates in the cells that produce the narrow streamers. Updrafts in these cells can reach about 7 mph (3 meters per second)—quite strong for a winter system. Once the streamers descend into the heart of the storm, they appear to merge into a broader area where smaller snowflakes collide and coalesce into larger flakes. Rauber and his research team are focusing on understanding these cloud-top features, a new aspect of winter storm dynamics made evident through PLOWS."

[CoastalWx]

Awesome stuff. Makes sense that in winter storms, while models may put out a general velocity or omega at a certain level, there exists mesoscale regions with enhanced updrafts. Thanks for posting that.

[baroclinic_instability]

Awesome stuff. Makes sense that in winter storms, while models may put out a general velocity or omega at a certain level, there exists mesoscale regions with enhanced updrafts. Thanks for posting that.

I am excited about seeing some of the research that comes out of this. What interested me the most was they mentioned much of this instability is not understood through typical mesoscale instabilities we already know of.

[MGorse]

Great stuff! It will be neat to see the findings of this research. The banding features especially during East Coast snowstorms are quite impressive and have an increased impact. Therefore, understanding the structure of them, and how instability on the mesoscale relates, even more will hopefully help with a better understanding of the true evolution of them.

[Amped]

Lightening is not that well understoopd mweather in a winter or summer storm.

[isohume]

Good stuff. UW seems to always have good cloud physics research going on. I wonder if they have the capability to add dual pol to their lidar? In any case it'll be interesting to see the results of this study and hopefully it's enough to make it into the mesoscale models.

[wxmeddler]

This was presented last year about some of the details of the study.

High resolution measurements of cyclone structure-the Profiling of Winter Storms Project