# Presentation: 502350

## WHERE DOES WEATHER COME FROM?

## GLOBAL CIRCULATIONS
JET STREAMS
VARIOUS CLIMATES
WEATHER MAKERS
AIR MASSES AND FRONTS
TROPICAL CYCLONES
OCEAN CURRENTS

**JET STREAMS**
**VARIOUS CLIMATES**
**WEATHER MAKERS**
**AIR MASSES AND FRONTS**
**TROPICAL CYCLONES**
**OCEAN CURRENTS**

## GLOBAL CIRCULATIONS

**EXPLAIN HOW AIR AND STORM SYSTEMS TRAVEL OVER THE EARTHS SURFACE**
**THINK OF THE EARTH AS A HEAT PUMP.**

## GLOBAL CIRCULATIONS

**IMAGINE A PLANET WITH NO ROTATION, TILT, OR WATER**
**IN THIS WORLD, THE SUN WOULD ALWAYS BE DIRECTLY OVER THE EQUATOR**
**AIR AT THE EQUATOR WOULD BECOME VERY HOT AND RISE INTO THE UPPER ATMOSPHERE**

## GLOBAL CIRCULATIONS

**THIS AIR WILL THEN MOVE TOWARD THE POLES WHERE IT WILL COOL AND SINK TO THE SURFACE**
**THE COLD AIR WOULD THEN MOVE ALONG THE SURFACE TOWARD THE EQUATOR**

## GLOBAL CIRCULATIONS

**THE RESULT IS ONE LARGE AREA OF HIGH PRESSURE AT THE POLES WITH A LARGE BELT OF LOW PRESSURE AT THE EQUATOR**

## GLOBAL CIRCULATIONS

**HOWEVER...THE EARTH DOES ROTATE, IS TILTED, HAS WATER, AND HAS LAND MASSES.**
**INSTEAD OF ONE LARGE CIRCULATION BETWEEN THE POLES AND EQUATOR...THERE ARE THREE******
**LETS DISCUSS THESE.**

## GLOBAL CIRCULATIONS

**HADLEY CELL**
**THIS IS THE LOWEST LATITUDE CELL. SURFACE AIR MOVES TOWARD THE EQUATOR AND FROM EAST TO WEST. WHEN HEATED...THIS AIR RISES VERTICALLY AND THEN MOVES POLEWARD ALOFT. **

## GLOBAL CIRCULATIONS

**FERREL CELL**
**MID-LATITUDE CELL. SURFACE AIR MOVES TOWARD THE POLES AND FROM WEST TO EAST. ALOFT...AIR IS MOVING TOWARD THE EQUATOR.**

## GLOBAL CIRCULATIONS

**POLAR CELL**
**HIGHEST LATITUDE MOST CELL.**
**SURFACE WIND MOVES TOWARD THE EQUATOR AND FROM EAST TO WEST. ALOFT...WINDS MOVE TOWARD THE POLES AND DESCEND WHEN THEY REACH THE POLES.**

## GLOBAL CIRCULATIONS

**INTERTROPICAL CONVERGENCE ZONES (ITCZ)**
**BELT OF LOW PRESSURE BETWEEN THE TWO HADLEY CELLS. SITUATED ROUGHLY NEAR THE EQUATOR.**
**ASSOCIATED WITH RISING AIR.**

## GLOBAL CIRCULATIONS

**HORSE LATITUDES**
**THE REGION AROUND 30 DEGREES BETWEEN THE HADLEY CELL AND FERREL CELL. THIS IS A BELT OF HIGH PRESSURE AT THE SURFACE WITH AIR DESCENDING FROM ABOVE.**
**CALLED HORSE LATITUDES FOR A REASON**

## JET STREAMS

**JET STREAMS ARE RIVERS OF STRONG WINDS IN THE UPPER LEVELS OF THE ATMOSPHERE THAT BLOW WEST TO EAST.**
**JET STREAMS FOLLOW THE BOUNDARIES BETWEEN HOT AND COLD AIR.**

## JET STREAMS

**JET STREAMS ARE STRONGEST DURING THE WINTER B/C THIS IS WHEN THE DIFFERENCE BETWEEN THE HOT AND COLD AIR IS STRONGEST.**
**TWO TYPES OF JET STREAMS.**
**POLAR JET...LOCATED BETWEEN THE FERREL CELL AND POLAR CELL (60****O****N)**
**SUBTROPICAL JET...LOCATED BETWEEN THE HADLEY AND FERREL CELL (30****O****N)**

## JET STREAMS

**JET STREAMS MEANDER AROUND THE GLOBE, DIPPING AND RISING IN ALTITUDE/LATITUDE, SPLITTING AT TIMES AND FORMING EDDIES.**
**JET STREAMS FOLLOW THE SUN’S ELEVATION ANGLE MOVING NORTH DURING THE SPRING AND SOUTH IN THE AUTUMN.**

## CLIMATE

**WHAT’S THE DIFFERENCE BETWEEN WEATHER AND CLIMATE?**
**WEATHER-VARIES FROM DAY TO DAY.**
**CLIMATE-SAME TYPE OF CONDITIONS OVER THE YEARS.**
**THE GLOBAL PATTERNS BASED UPON THE EARTH’S TILT, ROTATION AND LAND/SEA DISTRIBUTION ARE RESPONSIBLE FOR OUR CLIMATES**

## CLIMATE

**CLIMATES ARE CATEGORIZED ACCORDING TO LATITUDE, PRECIPITATION, TEMPERATURE.**
**TYPES OF CLIMATES:**
**TROPICAL (15****O****-25****O****)**
**WET (ALL YEAR LONG)**
**MONSOON (NEARLY ALL RAIN DURING HOTTEST MONTHS)**
**DRY WINTER SEASON (WET SEASON NOT THAT WET AND A PROLONGED DRY SEASON)**

## CLIMATE

**TYPES OF CLIMATES:**
**DRY CLIMATES (20****O****-35****O****)**
**FOUND INSIDE LAND MASSES**
**ARID (TRUE DESERT)**
**SEMIARID (GRASSLAND)...RECEIVES MORE PRECIPITATION THAN ARID.**

## CLIMATE

**TYPES OF CLIMATES:**
**MOIST SUBTROPICAL MID-LATITUDE CLIMATES (30****O****-50****O****)**
**WARM AND HUMID SUMMERS WITH MILD WINTERS.**
**TYPICALLY FOUND ON THE EASTERN AND WESTERN SHORES OF MOST CONTINENTS.**

## CLIMATE

**TYPES OF CLIMATES:**
**MOIST CONTINENTAL MID-LATITUDE CLIMATES**
**WARM TO COOL SUMMERS AND COLD, HARSH WINTERS.**

## CLIMATE

**TYPES OF CLIMATES:**
**POLAR CLIMATES**
**YEAR ROUND COLD TEMPERATURES WHERE WARMEST MONTH IS COOLER THAN 50****O**
**HIGLANDS**
**UNIQUE CLIMATE BASED ON ELEVATION.**
**OCCUR IN MOUNTAINOUS TERRAIN WHERE RAPID ELEVATION CHANGES CAUSE RAPID CLIMATIC CHANGES OVER SHORT DISTANCES.**

## STOP PLEASE!!!

## WEATHER PATTERNS

**TROPICAL WEATHER**
**OCEAN CURRENTS**
**EL-NINO**
**LA-NINA**
**GULF STREAM**
**AIR MASSES AND FRONTS**

## TROPICAL WEATHER

**TROPICAL CYCLONES**
**WARM CORE LOW PRESSURE SYSTEMS THAT DEVELOP OVER TROPICAL WATERS AND HAS AN ORGANIZED CIRCULATION.**
**HAVE DIFFERENT NAMES ACROSS THE WORLD**
**ATLANTIC/EASTERN PACIFIC - HURRICANES**
**WESTERN PACIFIC – TYPHOONS**
**INDIAN OCEAN - CYCLONES**

## TROPICAL CYCLONES

**ATLANTIC HURRICANE SEASON**
**JUNE 1****ST**** TO NOVEMBER 30****TH**** **
**PEAK ACTIVITY IS EARLY TO MID SEPT**

## TROPICAL CYCLONES

**TROPICAL CYCLONE FORMATION**
**WARM OCEAN WATERS (>80****O****)**
**HIGHLY UNSTABLE ATMOSPHERE**
**MUST BE AT LEAST 300 MI AWAY FROM  EQUATOR.**
**WEAK VERTICAL WIND SHEAR**
**A PRE-EXISTING SURFACE DISTURBANCE**

## TROPICAL CYCLONES

**TYPES OF DISTURBANCES**
**EASTERLY WAVES (TROPICAL WAVES) IS A REGION OF LOW PRESSURE MOVING WESTWARD.**
**WEST AFRICAN DISTURBANCE LINE (WADL) IS A LINE OF CONVECTION THAT FORMS OVER WEST AFRICA AND MOVES INTO ATLANTIC.**

## TROPICAL CYCLONES

**TYPES OF DISTURBANCES**
**TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) IS A COLD CORE LOW THAT CAN DEVELOP INTO A WARM CORE TROPICAL CYCLONE**
**OLD FRONTAL BOUNDARIES (OLD FRONTAL BOUNDARIES) IS A COLD FRONT THAT CAN STALL AND FORM INTO A CONVECTIVE COMPLEX.**

## TROPICAL CYCLONES

**CLASSIFICATION**
**TROPICAL DEPRESSION ******
**ORGANIZED CONVECTION W/ A CENTER OF CIRCULATION AND MAX WINDS OF 38MPH.**
**TROPICAL STORM**
**WINDS BETWEEN 38-73MPH**
**NAMES BEGIN AT THIS LEVEL**

## TROPICAL CYCLONES

**CLASSIFICATION**
**HURRICANES**
**SAFFIR-SIMPSON SCALE**
**CAT 1 (WINDS 74-95MPH)**
**CAT 2 (WINDS 96-110MPH)**
**CAT 3 (WINDS 111-130MPH)**
**CAT 4 (WINDS 131-155MPH)**
**CAT 5 (WINDS >155MPH)**

## TROPICAL CYCLONES

**CLASSIFICATION**
**HURRICANES**
**FIRST SYSTEM OF THE SEASON BEGINS WITH THE LETTER “A”.**
**ALTERNATE BETWEEN MALE AND FEMALE NAMES.**
**CAN BE EITHER FRENCH, ENGLISH, OR SPANISH.**
**NAMES CAN BE REPEATED EVERY SIX YRS**
**EXTREMELY DEVESTATING HURRICANES CAN HAVE THEIR NAMES RETIRED.**

## OCEAN CURRENTS

**CURRENTS CAN HAVE A BIG IMPACT UPON LOCAL WEATHER DUE TO WHERE THEY COME FROM.**
**EXAMPLES: GULF STREAM OFF THE SE US AND THE CURRENT OFF THE COAST OF CALIFORNIA.**

## EL-NINO/LA-NINA

**NORMALLY, SEA SURFACE TEMPERATURES  IN THE WESTERN PACIFIC ARE ABOUT 14****O**** WARMER THAN THE EASTERN PACIFIC.**
**EASTERN PACIFIC IS COOLER DUE TO UPWELLING.**

## EL-NINO/LA-NINA

**DURING EL-NINO, THE WATERS IN THE EASTERN PACIFIC ARE WARMER THAN NORMAL.**
**EFFECTS INCLUDE: MORE RAINFALL IN THE EASTERN PACIFIC...DRIER IN THE WESTERN PACIFIC...WEAKER TRADE WINDS WHICH FAVOR TROPICAL DEVELOPMENT.**

## EL-NINO/LA-NINA

**LA NINA IS A CONDITION WHERE WATERS ARE COOLER THAN NORMAL ACROSS THE EASTERN PACIFIC.**
**RESULTS INCLUDE STRONGER TRADE WINDS WHICH RESULT IN A PILING UP OF WATER ACROSS THE WESTERN PACIFIC.**
**SO...HOW DOES THIS IMPACT US?**

**EL NINO - WINTER**

**EL NINO - SUMMER**

**LA NINA - WINTER**

**LA NINA - SUMMER**

## AIR MASSES

**AIR MASSES ARE LARGE BODIES OF AIR W/ SIMILAR TEMPERATURES AND HUMIDITIES.**
**AIR MASSES FORM OVER “SOURCE REGIONS”**
**WHEN AN AIR MASS STAYS UNDISTURBED OVER A PARTICULAR AREA IT WILL TAKE ON THE SURFACE CHARACTERISTICS OF THAT AREA.**

## AIR MASSES

**THE U.S. IS NOT A FAVORABLE SOURCE REGION B/C OF THE NUMBER OF DISTURBANCES THAT PREVENT THE AIR FROM STAGNATING.**

## AIR MASSES

**TYPICAL AIR MASSES THAT IMPACT THE U.S. INCLUDE**
**POLAR LATITUDES**
**CONTINENTAL AIR MASSES**
**MARITIME AIR MASSES**
**TROPICAL AIR MASSES**

## AIR MASSES

**BOUNDARIES BETWEEN TWO AIR MASSES ARE FRONTS.**
**FRONTS ARE CLASSIFIED BY THE TYPE OF AIR MASS THAT IS REPLACING THE OTHER. **
**FOUR TYPES OF FRONTS**
**COLD FRONT**
**WARM FRONT**
**STATIONARY FRONT**
**OCCLUDED FRONT**

## AIR MASSES

**FRONTS DON’T JUST EXIST AT THE SURFACE...THEY HAVE A VERTICAL PROFILE OR SLOPE.**
**COLD FRONTS USUALLY MOVE FASTER THAN WARM FRONTS. AS A RESULT...THEY CAN CATCH UP TO A WARM FRONT. WHEN THE TWO MERGE...AN OCCLUDED FRONT RESULTS.**

## AIR MASSES

**FRONTS ARE DETECTED ON WEATHER MAPS IN THREE WAYS:**
**SHARP WIND SHIFT**
**NOTICEABLE DIFFERENCE IN TEMPERATURE/HUMIDITY**
**LOWER PRESSURE**