Weather and Forecasting Diagnostics

• ASCENDING motion
• CLOCKwise turning
• VEERING

• DESCENDING moti
• COUNTERclockwise turning
• BACKING

High-pressure systems force air downward; This force prevents air near the ground from rising; The sinking air acts like a cap; It traps warm ground air in place; Without rising air, there was no rain, and nothing to prevent the hot air
from getting hotter

1. Bergeron (ice-crystal) process
2. Collision-and-coalescence

0.5 mm

ABOVE; BELOW

32 F

Ice particles form when raindrops FREEZE while falling through a COLD air layer & Above freezing air layer must overlie a subfreezing layer near the ground

Supercooled raindrops freeze on CONTACT with solid objects (Subfreezing lower
air layer is NOT thick enough for raindrops to freeze)

1. Buoyancy
2. Moderate to strong speed and directical wind shear (surface to 20,000 ft is CRITICAL)
3. Mesoscyclone (storm tilted to seperate up/down draft region)
4. Seperate updraft and downdraft (long-lived; reduces too much rain-cooled, stable air from downdraft region to be ingestes into updraft)