WEATHER NOTES WEATHER THE ATMOSPHERIC CONDITIONS ALONG WITH

WEATHER NOTES

WEATHER • THE ATMOSPHERIC CONDITIONS, ALONG WITH SHORT-TERM CHANGES, OF A CERTAIN PLACE AT A CERTAIN TIME • WEATHER CONDITIONS CAN CHANGE WITHIN A FEW HOURS OR LAST OVER SEVERAL DAYS IN A ROW • WEATHER DEPENDS ON SEVERAL VARIABLES THAT AFFECT ATMOSPHERIC CONDITIONS

WEATHER VARIABLES AIR TEMPERATURE – THE MEASURE OF THE AVERAGE KINETIC ENERGY OF MOLECULES IN THE AIR PRESSURE – THE FORCE THAT A COLUMN OF AIR APPLIES ON THE AIR OR A SURFACE BELOW IT WIND SPEED AND DIRECTION (WIND IS THE MOVEMENT OF AIR FROM AREAS OF HIGH PRESSURE TO AREAS OF LOW PRESSURE)

(VARIABLES CONTINUED) • HUMIDITY – THE AMOUNT OF WATER VAPOR IN THE AIR • CLOUD COVERAGE • PRECIPITATION – WATER, IN LIQUID OR SOLID FORM, THAT FALLS FROM THE ATMOSPHERE

RELATIVE HUMIDITY VS. DEW POINT • RELATIVE HUMIDITY TELLS US HOW CLOSE AIR IS TO SATURATION. • DEW POINT TELLS US THE TEMPERATURE AT WHICH WATER VAPOR WILL BECOME SATURATED ENOUGH TO CONDENSE IN THE ATMOSPHERE TO EITHER FORM CLOUDS, FOG, OR DEW

CLOUD FORMATION • WATER HEATED BY SUNLIGHT EVAPORATES AND TURNS INTO WATER VAPOR THAT RISES IN THE ATMOSPHERE AND COOLS • WHEN THE COOLING AIR REACHES ITS DEW POINT, WATER VAPOR CONDENSES ON SMALL PARTICLES (LIKE DUST, ASH, AND POLLEN) TO FORM DROPLETS • THE DROPLETS COMBINE TO FORM CLOUDS

TYPES OF CLOUDS • STRATUS – LOW ALTITUDE CLOUDS THAT FORM IN FLAT LAYERS AND ARE GRAY • CUMULUS – FLUFFY WHITE CLOUDS THAT LOOK LIKE COTTON BALLS AND FORM AT MEDIUM ALTITUDES • CIRRUS – HIGH ALTITUDE CLOUDS

CLOUDS THAT FORM PRECIPITATION • NIMBOSTRATUS – VERY DARK GRAY LOW ALTITUDE CLOUDS THAT PRODUCE LIGHT STEADY PRECIPITATION • CUMULONIMBUS – CLOUDS THAT EXTEND FROM LOW TO HIGH ALTITUDE AND PRODUCE

TYPES OF PRECIPITATION • RAIN – PRECIPITATION THAT REACHES EARTH’S SURFACE AS DROPLETS OF WATER • SNOW – PRECIPITATION THAT REACHES EARTH’S SURFACE AS SOLID, FROZEN

(PRECIPITATION CONTINUED) • SLEET – SNOW MELTS AS IT FALLS THROUGH A LAYER OF WARM AIR AND REFREEZES WHEN IT PASSES THROUGH A LAYER OF BELOW-FREEZING AIR TO FORM ICE PELLETS • HAIL – A SMALL PIECE OF ICE THAT IS REPEATEDLY LIFTED AND DROPPED BY AN UPDRAFT WITHIN CUMULONIMBUS CLOUDS AND ADDS A LAYER OF ICE WITH EACH

THE WATER CYCLE • A SERIES OF NATURAL PROCESSES BY WHICH WATER CONTINUALLY MOVES AMONG OCEANS, LAND, AND THE ATMOSPHERE • EVAPORATION – WATER ON EARTH’S SURFACE TURNS TO WATER VAPOR WHEN HEATED AND RISES IN THE ATMOSPHERE

(WATER CYCLE CONTINUED) • CONDENSATION – WATER VAPOR IN THE ATMOSPHERE CONDENSES BACK INTO A LIQUID TO FORM CLOUDS • PRECIPITATION – LIQUID OR SOLID WATER THAT FALLS FROM THE