2. Precipitation

3. Precipitation Any form of moisture that falls from the sky

4. The main forms are Rain Rain Snow Snow Sleet Sleet Hail Hail

5. Rain Liquid precipitation Liquid precipitation Varies in size Varies in size Normal raindrops between 0.5 to 5 mm Normal raindrops between 0.5 to 5 mm Less that 0.5 mm drizzle Less that 0.5 mm drizzle

6. Snow May be Small pellets Individual crystals or Crystals that combine to form snowflakes Large at temps near 0 C and become smaller at lower temperatures

7. Sleet When snow falls through a layer of freezing air near the surface When snow falls through a layer of freezing air near the surface

8. Damaging Precipitation http://www.chaseday.com/hailfall.htm

9. Hail Solid precipitation in lumps of ice Spherical or lumps Forms in cumulonimbus clouds

10. Remember Convection!!!! Convection Hot, less dense air rises Requires daytime heating Patches of sunlight help Updrafts (in red) rise as ground surface is heated by the sun above ambient air temperatures (blue).

11. Formation of Hail Formation of Hail

12. Hail Formation Hail stones form by accretion Small hail gets caught up in the updraft and goes to the top of the cloud where it receives another layer of ice This repeats until the hail cannot be supported by the updraft and it falls

13. Hail requires strong updrafts to form For the smallest hail to form, an updraft of around 36 to 54 km/h (24-34 mph) is required. golf-ball size (1 3/4 inch diameter) -- require updrafts of around 88 km/h (55 mph) to form. Softball-size hail involves updrafts exceeding 160 km/h (100 mph).

15. “like driving on ball bearings” http://www.chaseday.com/hailfall.htm

16. Record Hail Record hail fell in Coffeyville, KS diameter 14.4 cm (5.67 inches) Credit: NOAA Photo Library

17. Punching the core Punching the core

18. Hail Sizes Pea6.4 millimeters (0.25 in) Pea Dime17.9 millimeters (0.70 in) Dime Penny19 millimeters (0.75 in) Penny Nickel21.2 millimeters (0.83 in) Nickel Quarter24.26 millimeters (0.955 in) Quarter Half dollar30.6 millimeters (1.20 in) Half dollar Walnut38 millimeters (1.5 in) Walnut Golfball44 millimeters (1.7 in) Golfball Tennis Ball64 millimeters (2.5 in) Tennis Ball Baseball70 millimeters (2.8 in) Baseball Grapefruit108 millimeters (4.3 in) Grapefruit Softball114 millimeters (4.5 in) Softball

21. Measuring Precipitation A Rain gauge is used to measure liquid precipitationRain gauge

22. Doppler Radar Doppler radar is a key forecasting tool Based on the Doppler principle also used with light and sound

23. All weather radars send out radio waves from an antenna. Objects in the air, such as raindrops, snow crystals, hailstones or even insects and dust, scatter or reflect some of the radio waves back to the antenna. All weather radars, including Doppler, electronically convert the reflected radio waves into pictures showing the location and intensity of precipitation. By Jack Williams, USATODAY.com By Jack Williams, USATODAY.com

24. Remember the meteorologist saying the wind is blowing towards or away from the radar Used to indicate rotation in a thunderstorm which could indicate a tornado forming