310lect6

Climate

I. Introduction

A. Moist Subtropical

II. Climatic Controls

A. Latitude

1. Main control on temperature

a. Sun angle

b. Length of daylight

B. Continental and Marine Influences

1. Continentality

a. Heats up fast, cools fast

2. Marine climate

a. moderation

C. Ocean Currents

1. Gyres

2. Gulf Stream

D. Topography

1. Rockies

2. Local topography

E. Dominant Air Masses

1. Maritime Tropical

2. Continental Polar

3. Maritime Polar

F. Prevailing Winds

1. Westerlies

a. Winter

2. Easterlies

a. Summer

III. Temperature and Precipitation Patterns

A. Average Minimum and Maximum Temperatures

1. See maps

2. Minimal statewide range during summer

3. Greater range statewide during winter

4. Frequency of thunderstorms in the southern half of state lowers avg. temp.

5. Hotter in the North during the summer on Average, colder in the North too.

B. Frost Dates

1. Important for agriculture.

C. Growing Season

1. Dtermined by frost free calendar

2. Important for agriculture

D. Heat Index

1. Factors in humidity

2. Makes the southern part of the state seem warmer

E. Average Annual Precipitation

1. High average (2^nd in the US)

2. Most in coastal areas, especially Florida parishes

a. Terraces cause uplift

b. Mt. Driskill

F. Winter Precipitation

1. Frontal

2. Wave cyclones

3. Cold Fronts

a. More intense rain and more rapid change of temperature

4. Warm Fronts

a. Can be seen coming by the type of clouds

b. Steady rain for several days

c. Possible thunderstorms

G. Summer Precipitation

a. Mostly convectional uplift

b. Cumulus

c. Cumulonimbus

d. Downdrafts

IV. Severe Weather Systems

A. Tornadoes

a. Most common in spring time, then in November

b. Can hit anywhere in Louisiana

c. More common on western edge of lala

B. Hurricanes

a. Late summer

b. Form out in the Atlantic Ocean

c. Dangerous

i) Wind

ii) Rain

iii) Tornadoes

iv) Floods

v) Storm surge

d. New Orleans is highly vunerable to Hurricanes

V. Regional Climate Patterns

A. North Louisiana

a. Hotter, dryer in summer

b. Colder in winter

c. Less convectional storms in summer

B. Southwest Louisiana

a. Mild

b. Heaviest snowfall in Rayne (2 ft)

C. Southeast Louisiana

a. Most rainfall

b. Hurricane prone

c. Small temperature ranges

D. Central Louisiana

VI. Long Term Climate Trends

1. Long range cooling?

2. Wetter?

VII. Conclusion