1. Weather Maps Isolines- Lines which connect points
of equal value on a diagram
or map.
Isotherms- Lines which connect points of equal temperature on a
weather map.
Isobars- Lines which connect points of equal barometric pressure
on a weather map.

4. Interval- The difference in value between two consecutive isolines.
Gradient- A mathematical expression of the change in value
between two locations.
G= Change in field value ESRT Front Page
Distance

5. 1. Large gradients are indicated by close isolines on a map.
2. Areas where there is little change in temperature or air
pressure between locations are indicated with isolines that
are far apart.
A large pressure gradient and close isobars indicate
high wind speeds.
To find the highest possible value on a map, find the highest
isoline, add the interval and subtract 1.
Isoline Map Practice

6. Local Winds are created by unequal heating of Earth’s surface that creates a pressure gradient over a fairly short distance.
Sea Breeze- A local daytime wind from water toward land
due to unequal heating of land and water.

7. Land Breeze- A local nightime wind from land toward water
due to unequal cooling of land and water.

8. Coriolis Effect- Earths rotation causes winds to be deflected
to the right in the Northern Hemisphere and
left in the Southern Hemisphere.

9. Coriolis Video

10. Low Pressure- Warmer, cloudy wet conditions.
Winds move inward, upward and counterclockwise in the
Northern Hemisphere. Rising air expands and cools to the dew
point producing clouds and precipitation.
High Pressure- Cooler, dry, clear conditions.
Winds move outward, downward and clockwise in the
Northern Hemisphere. Sinking air warms due to compression
so few clouds form.

11. H L Wind moves from High to Low or Low to High Air Pressure?
BUT, will the wind have a straight path between High and Low?
Why or Why Not?

12. Wind movement Power Point

13. Which way will Air rotate, as it rushes into a Low Pressure area?

14. Will Surface Winds converge or diverge at Low Pressure Area?
Ground Level

15. Which way will Air rotate, as it rushes away from a High Pressure area?

16. Will Surface Winds converge or diverge at High Pressure Area?
Ground Level

17. Planetary Winds- Prevailing winds that are created by
the unequal heating of the Earth and
given direction by the coriolis effect.
ESRT page 14
North America is located in the South West Winds.
These winds are commonly referred to as the
Prevailing Westerlies. They move weather systems
From west to the east or northeast at a rate of 500 to
800 miles per day.

18. Planetary Winds
To view this animation, click “View” and then “Slide Show” on the top navigation bar.

20. Jet Stream- High altitude streams of air that move with the
prevailing winds.

21. What will temperatures be like in Rochester, when the Jet Stream is to the North of New York?
What will temperatures be like in Rochester, when the Jet Stream is to the South of New York?

22. Jet streams move northward in summer moving warmer
air across the United States, and southward in winter,
bringing cold air southward from Canada.
Air masses: Large bodies of air with uniform characteristics of
temperature and humidity.
Source Region: The area where an air mass forms. The
characteristics of an air mass are similar
to the source region.

23. cA- Continental Arctic: Very Cold and Dry
cP- Continental Polar: Cold and Dry
cT- Continental Tropical: Warm and Dry
mP- Maritime Polar: Cold and Humid (Wet)
mT- Maritime Tropical: Warm and Humid

24. cA cP mP cT mT

26. Weather Front- The boundary between two air masses with
different characteristics.
1. Fronts are associated with low pressure and often bring clouds
and precipitation.
2. The severity of the weather along a front depends upon
the difference in temperature and humidity. Large
differences lead to more severe weather.

27. Formation of a Front cP L mT

28. Cold Front- Cold air pushes warm air. Warm air rises along the
front producing a steep frontal boundary with
a narrow band of rain and thunderstorms at and
slightly behind the front.
Cold Fronts often bring short intense rainfall followed by
decreasing temperatures.

29. Warm Front- Warm air pushes cold air. Warm air rises along
the front, producing a shallow frontal boundary,
with clouds and precipitation extending ahead
of the front.
Warm fronts often bring long periods of rain,
followed by increasing temperatures.

30. Cold Fronts and Warm Fronts
Characteristics of Fronts
Cold Fronts and Warm Fronts
To view this animation, click “View” and then “Slide Show” on the top navigation bar.

31. Occluded Front- Warm air is trapped between two colder air masses
Occluded Front- Warm air is trapped between two colder air masses. Occluded fronts may bring long periods of rain and are associated with ice storms.

32. Occluded Front Development

33. Stationary Front- A front which is not moving.
Stationary fronts may bring extended
periods of cloudy, unsettled weather.
Front Symbols- Page 13 ESRT
Cold Front
Warm Front
Occluded Front
Stationary Front

36. Severe Weather
Hurricanes- Large, low pressure tropical storms that form over warm oceans. Hurricanes gain energy from evaporating ocean water and quickly die over land.
Most deaths and damage are caused by storm surges and flooding in coastal areas.
The southeast and Gulf Coast of the United States are most likely to experience a hurricane.
Hurricanes last for several days and may affect large areas of coastline.

40. Hurricane Preparation:
Evacuate coastal areas.
Board up windows and secure objects that may be damaged or destroyed by high winds.
3. Have extra non-perishable food, water, flashlights and other emergency
supplies on hand.

45. Tornados- A funnel shaped cloud of high speed whirling wind
associated with severe thunderstorms.

46. Most tornados occur in the south and central
United States during spring and summer.
Damage from wind may be severe, but often
covers only a small area.
3. Tornados are difficult to forecast and we often have
little warning before they occur.
Move to an interior room, basement, or low area to
avoid flying debris.

47. Technology and Weather forecasting:
Deaths from severe weather have been reduced greatly over
the past 60 years. Improvements in satellites, radar and
computer forecasting models give us the ability to track
weather systems and give people advanced warning of
dangerous weather.

48. Hurricane Katrina Track August 2005