Expert: Tom Whiting - 11/30/2009

Question
QUESTION: What are the types of precipitation found in NY seasonally during the entire year?

ANSWER: Hi Cynthia,
All 9 different types of precipitation are found in the New England region, including my
home state of PA...4 liquid and 5 solid types.
5 Solids:
Hail from thunderstorms, more a springtime ppt.  You need a thunderstorm for hail (and tornado).
sleet -soft mushy ice.
graupel, also called "snow pellets"- spherical balls of ice that bounce or shatter when impacting a hard surface.
snow...forms from deposition only (gas directly to a solid, that's why they are 6 sided.)
snow grains, the nucleus of a snow flake. (also called angel dust I believe).

4 liquids:
Large raindrops from vertical air movement - from cumulus type clouds.
small drizzle drops from stable air, horizontal - from stratus type clouds.
freezing rain...need a temperature inversion at the surface for that one.
Virga...rain that evaporates before it strikes the ground.
Virga is the rarest east of the Mississippi, it's more a western state phenomenon, but
it does occasionally occur in our region.

This doesn't count the real rare forms of ppt. like snow rollers, colored rain, fish falling
from the sky due to a tornado over a pond, etc.  Also, dew and frost do not "fall"...dew forms
when saturated air condenses on a cold surface, and frost is deposition on a cold surface.
(deposition is the opposite of sublimation...gas directly to the solid state, bypassing the
liquid state).
Clear skies,
Tom Whiting
Erie, PA

---------- FOLLOW-UP ----------

QUESTION: How can you compare NY precipitation to Georgia?

Answer
Georgia, especially southern Georgia, is nearly a sub-tropical region...so they are subject
to little (rare) heavy wintertime precipitation like snowfalls, sleet, and graupel. It's 10-30 degrees warmer temperatures than we are, and therefore much stronger thunderstorms in the spring and summer months. The humidity is also higher when winds come off the Gulf of Mexico and/or the warm Atlantic waters. They get more mT air masses than we do...we get more cP air up here from
Canada.
Georgia being on the coast can occasionally suffer a hurricane, whereas we in the NE are not generally hit initially by a hurricane.  Of course, you might want to divide Georgia (the largest state east of the Mississippi River), into 2 separate catagories. Northern Georgia with the mountains around Dalton and Rome, is more temperate than sub-tropical, unlike the southern end down by Brunswick and Valdosta. So basically Georgia has two climates.
Clear Skies,
Tom
mT air mass...maritime tropical air...moist and warm.
cP air mass ...continental polar air...dry and cool.