1. Lab 8 November 6 th, 2013

2. Hurricane Review  Winds rotate counter-clockwise around the center  Storm surge is caused by the wind; a wind-driven rush of sea into coastal areas as a strong tropical cyclone arrives  Greater wind velocity results in stronger storm surge

3. Southern Hemisphere?  Remember, Coriolis deflects the wind to the left. How does that affect wind flow around lows and highs?

4. Hurricane Formation/Intensification  Hurricanes thrive off of warm, moist air (this is why they tend to form over water near the equator!)  Intensification occurs when the hurricane continues to feed on the energy from these warm waters  Oftentimes, the wind from a slow moving cyclone agitates surface of the ocean, bringing deeper water to the surface, analogous to upwelling  How does this affect the ocean temperature, and thus the storm’s intensification?

5. Convergence/Divergence  Convergence = air coming together  Surface convergence is associated with surface lows L  Divergence = air moving away  Surface divergence is associated with surface highs H

6. Surface – Upper Air Interaction LH Surface pressure is proportional to the weight of the column of air above Decreasing weight leads to strengthening surface lows, increasing weight leads to strengthening surface highs Decreasing column weight

7. Advection  Transport of a quantity by the wind  Often interested in temperature advection  Depends on:  Strength of the wind  Angle that the wind crosses isotherms  Temperature gradient

8. Reading Wind Barbs Credit: http://nycmetnet.ccny.cuny.edu

9. Advection - Example  What will the temperature be in one hour? Hint: 1 knot = 1 nautical mile.  In 1 hour, the isotherm pattern will be advected 30 nm to the south.  Just look at the temperature 30 nm to the North, 20 degrees! 20 30 40 50 60 0 nm 30 nm

10. Fronts  When defining fronts, cold air calls the shots  Cold Front = Cold air advancing  Warm Front = Cold air retreating  How do we locate fronts?  Temp gradient  located at leading edge of cold air  Wind directions  located where wind directions change abruptly  Surface pressure  located in a trough of low pressure

11. Cold Front Placement

12. Lab Assignment 11.1 (b) 11.13 12.10 (a, b, c, d) 12.11 (a, b) 13.1 (a, b) 13.2 (a, c) 13.7 (a, b) Office hours  Thursday’s from 6-7 pm in Wx Center