QG Theory & Weather Systems Team 2 Alyssa Halm Matt Sanders

QG Theory & Weather Systems

Team 2

Alyssa Halm

Matt Sanders

The 850mb temperature advection corresponds quite well with the cloud pattern at 0Z. There is strong waa in the area where convection is occurring at 0z as evident by the clouds over central IL. The radar depicts a strong line of convection over this region. Where there is strong caa, over northern MO, it is clear. This means that the temperature advection patterns lines up nicely with the cloud and precipitation patterns at 0z. The waa is likely one of the factors producing the convection. However, at 12z this is not the case as the temperature advection patterns do not align with the areas of convention. In fact, there is now widespread caa over a portion of the convection occurring in VA and NC. This means that the temperature advection is probably not a factor in producing this convection.

The vorticity advection pattern also corresponds well with the cloud and radar features at 0z. A large area of positive vorticity advection is present over IL. This overlays well with the cloud pattern present at that time. The radar imagery lines up well with the positive vorticity field. The negative vorticity fields at 0Z match up with the clear and precipitation free areas on the satellite and radar. This indicates that upward motion associated with positive vorticity is aiding in the production of clouds and precipitation. Meanwhile the negative vorticity and associated downward motion are resulting in clear areas. The upward motion is also being supported by the flow around the base of the shortwave trough which is producing divergence over IL. At 12Z the agreement between the vorticity advection, cloud, and propitiation patterns is less than ideal. Slide 8 shows that a large area of negative vorticity advection overlays the clouds present over NC. The area of positive vorticity advection that does remain over the clouds, near WV, is quite weak. The radar reflectivity shows a much weaker line of convention at 12Z, likely do to this lack of strong upward vertical motion.

The 700mb thetae gradients depict the front nicely at both 0Z and 12Z. At 0Z the thatae gradient indicates a frontal boundary stretching thorough IL. 12 hours later the frontal boundary is shown near the spine of the central Appalachian Mountains. In both instances the cloud and precipitation patters match up well with the thatae depiction of the frontal boundary.