Monday, May 8th Entry Task When an air mass reaches a new location, what does it bring with it? Schedule: Weather Fronts Objective: I will describe a weather front as a boundary between air masses Homework: Complete the questions on page 581, IQIA Please have on your desk: ISN open to air mass notes

Fronts and Weather A front is a boundary between air masses. (different fronts cause different weather patterns)

What a cold front looks like: A cold front forms when a cold air mass forces warm air to rise; forms tall clouds. These travel pretty fast. The warm air gets quickly pushed up by the cold air mass. This causes the atmosphere to become unstable The rapidly cooled water vapor from the warm air condenses and forms tall cumulonimbus clouds. Thunderstorms usually occur. ( rain) What a cold front looks like: In the winter, a cold front may cause the temp to drop a lot. In the summer, cold fronts produce drier, cooler air

What a warm front looks like: A warm front forms when a warm air mass pushes a cold air mass; forms flat clouds. These happen more gradually over time. Warm air slowly rises over and replaces the colder, denser air The air along the border of the two air masses, the warm air condenses to creating a blanket of clouds in the sky. Warm fronts bring with them extended periods of rain, sleet or snow. What a warm front looks like: As it approaches, high cirrus then high stratus clouds form. The clouds will get lower and lower Many hours of precipitation ( think PNW in the winter.)

Similarities between Warm and Cold fronts Use this time to discuss what Warm and cold fronts have in common Both can bring rain Both move from E to W Both change in temp and weather conditions Both are boundaries between two contrasting air masses

A stationary front occurs when two air masses push against each other. There is a lack of air mass movement for a period of time. The air in the cold and warm air masses may still move side to side But for the most part it just stays “stationary” ( no movement) What a stationary front looks like: Cloudy skies

High and Low Pressure Systems A high pressure system is formed when air moves all the way around a high-pressure center. When a high pressure-system stays in one location for a long time, an air mass may form.

A low pressure system is a large weather system that surrounds a center of low pressure. It begins as air moves around and inward toward the lowest pressure and then up to higher altitudes.

Tuesday, May 9th Entry Task If a high pressure system moved over us, what would happen to the weather? Schedule: 17.2 Storms Objective: I will explain how hurricanes develop. Homework: 17.2 questions 1-6, page 587, IQIA Please have on desk: ISN open to 17.1 questions

Hurricanes begin over warm ocean waters when evaporated sea water and wind patterns near the ocean surface spirals inwards usually occur from August to October Southeast U.S. region experiences the largest number of hurricanes [most vulnerable cities include: Tampa, Miami, New Orleans, Norfolk, and Houston]

Types of Hurricanes Category One - Winds 74-95 mph Category Two - Winds 96-110 mph Category Three - Winds 111-130 mph Category Four - Winds 131-155 mph Category Five-- Winds greater than 155 mph

Number of Hurricanes Yearly Hurricane Average: Atlantic Basin 2 to 12 hurricanes Eastern Pacific Ocean 4 to 14 hurricanes

Death by Hurricane An estimated 10,000 people die each year worldwide due to hurricanes and tropical storms.

Wednesday, May 10th Entry Task Why do hurricanes generally form near the end of summer? Schedule: Inside the Megastorm Objective: I will observe the causes and effects of a large hurricane Homework No homework Please have on desk: Clear off your table

Thursday, May 11th Entry Task According to scientists, what seems to be causing the jet stream to become more extremely wavy? Schedule: 17.3 Severe Storms Objective: I can explain how tornadoes and thunderstorms are formed Homework: 17.3 Questions, page 592, IQIA Please have on desk: ISN open to 17.2 questions

Thunderstorms CAUSED BY: moisture from clouds and rain unstable air (warm air can be rising rapidly) a lift caused by fronts, sea breezes or mountains

Types of Thunderstorms Air Mass Thunderstorms (localized convection in an unstable air mass) Frontal Thunderstorm (form ahead of a cold front) Orographic thunderstorms (result from air that is forced upward by a mountain)

Number of Thunderstorms An estimated 100,000 thunderstorms occur in the U.S. yearly with about 10% classified as severe.

Death by Thunderstorm On average, 80 people are killed and 300 injured each year by lightning. Another 140 deaths occur each year from flash floods.

Tornadoes caused by instability (warm humid air) and wind shear (wind changing directions) in lower atmosphere occur from March to August Central U.S. experiences the largest number

Types of tornadoes F-0 -- Winds 40 - 72 mph F-1 -- Winds 73 - 112 mph

Number of tornadoes Approximately 1,300 tornadoes hit the U.S. yearly.

Death by tornado On average 860 people are killed by tornadoes each year.

Friday, May 12th Entry Task What makes a tornado become visible? Schedule: 17.2 & 17.3 Review 17.4 Forecasting Tech Objective: I will describe the technology used in weather forecasting. Homework 17.4 RSG Please have on desk: ISN