WEATHER, WHY WORRY ABOUT IT?

PICTURES MADE IN MISSISSIPPI AS KATRINA MOVED IN

WHY SHOULD WE BE CONCERNED OR WORRY ABOUT WEATHER? WHY SHOULD WE WANT TO MEASURE “WEATHER”, KEEP RECORDS OF WEATHER, AND TRY TO PREDICT WEATHER?

12 JANUARY 1888 – FIERCE BLIZZARD SWEPT DOWN ON NEBRASKA AND THE DAKOTA TERRITORY. WIND CHILL DROPPED TO -40 o F. BEFORE IT HIT, IT HAD BEEN A MILD DAY. THE WEATHER OFFICE IN ST. PAUL, MN HAD PREDICTED IT, AND SENT OUT A WARNING BY TELEGRAPH. MOST PEOPLE LIVED FAR AWAY FROM TELEGRAPH LINES AND OFFICES. POSSIBLY AS MANY AS 500 PEOPLE DIED – MANY LOST IN THE STORM, AS VISIBILITY DROPED TO ZERO. KNOWN AS THE “CHILDREN’S BILIZZARD, AS MANY KIDS WERE LEAVING SCHOOL WHEN IT HIT.

ANOTHER BIG BLIZZARD TOOK PLACE THAT SAME YEAR – MARCH, A HUGE NORTHEASTER MOVED UP THE COAST HITTING NEW YORK AND NEW ENGLAND WITH HEAVY SNOW AND HIGH WINDS.

THE GREAT BLIZZARD OF 1888

SINCE THE STORM MOVED UP OFF SHORE, NO ONE WAS ABLE TO PREDICT IT. AN ESTIMATED 300 PEOPLE IN NYC LOST THEIR LIVES. ABOUT 200 SHIPS WERE SUNK AND NEARLY 100 LIVES WERE LOST AT SEA. ANOTHER UNFORSEEN WEATHER EVENT WAS THE 1900 GALVESTON HURRICANE IN WHICH 6,000 PEOPLE LOST THEIR LIVES.

SO, WHAT’S WEATHER??

WEATHER “THE STATE OF THE ATMOSPHERE AT SOME PLACE AND TIME.” - Joseph Moran, “Weather Studies” – WE ATTEMPT TO DESCRIBE WEATHER IN QUANTITATIVE TERMS – TEMPERATURE, HUMIDITY, CLOUDINESS (TYPE AND COVER), PRECIPITATION (TYPE AND AMOUNT), WIND SPEED, WIND DIRECTION. THE ACTUAL SCIENCE THAT STUDIES WEATHER IS METEOROLOGY – “STUDY OF THE ATMOSPHERE AND THE PROCESSES THAT CAUSE WEATHER.”

CLIMATE – “ARITHMETIC AVERAGES OF WEATHER ELEMENTS TAKEN OVER YEARS” - JOSEPH MORAN – AVERAGES ARE TAKEN OVER A 30 YEAR PERIOD BEGINNING WITH THE 1 ST YEAR OF A DECADE. CLIMATE GOVERNS MAY THINGS, EVEN THE TYPE OF ECOSYSTEM. CLIMATE DETERMINES: THE FRESH WATER SUPPLY, HEATING AND COOLING REQUIREMENTS, CLOTHING AND HOUSING REQUIREMENTS, TYPES OF FOOD THAT CAN BE GROWN, ETC.

WHERE DO WE GET WEATHER INFORMATION?

1)TV 2)RADIO 3)NEWSPAPERS 4)INTERNET 5)NOAA WEATHER RADIO 6)PERSONAL OBSERVATION NOAA – NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION (NATIONAL WEATHER SERVICE IS PART OF THIS)

WHERE DOES NOAA GET ITS WEATHER INFORMATION? 1)ASOS – AUTOMATED SURFACE OBSERVING SYSTEMS 2)RADAR 3)SATELLITES 4)SHIPS AND BOUYS

SOME OF THE DATA MIGHT INCLUDE: 1)MAXIMUM TEMPERATURE – HIGHEST TEMPERATURE RECORDED OVER A 24 HOUR PERIOD – GENERALLY OCCURS EARLY TO MID AFTERNOON 2)MINIMUM TEMPERATURE – LOWEST TEMPERATURE OVER A 24 HOUR PERIOD – USUALLY AROUND SUNRISE 3)DEW POINT – TEMPERATURE, ON COOLING, WHERE THE AIR BECOMES SATURATED WITH WATER VAPOR – TEMP. AT WHICH DEW OR FROST WOULD FORM 4)PRECIPITATION AMOUNT – DEPTH OF RAINFALL OR SNOWFALL IN INCHES OVER A 24 HOUR PERIOD (10 “ OF SNOW = 1 “ OF RAIN 5)AIR PRESSURE – WEIGHT OF A COLUMN OF AIR OVER A UNIT AREA OF EARTH 6)WIND DIRECTION AND SPEED – DIRECTION FROM WHICH THE WIND IS BLOWING

7) CLOUD TYPE AND COVER 8) RELATIVE HUMIDITY – THE AMOUNT OF MOISTURE IN THE AIR DIVIDED BY THE MAXIMUM AMOUNT AT THAT TEMPERATURE TIMES 100 9) BAROMETRIC PRESSURE

NWS ASOS STATIION WEATHER CONDITIONS ARE REPORTED AND USED TO UPDATE THE FORECAST 12 TIMES EACH HOUR. Sky conditions such as cloud height and cloud amount up to 12,000 feet, Surface visibility up to at least 10 statute miles, Basic present weather information such as the type and intensity for rain, snow, and freezing rain, Obstructions to vision like fog, haze, and/or dust, Sea-level pressure and altimeter settings, Air and dew point temperatures, Wind direction, speed and character (gusts, squalls), Precipitation accumulation, and Selected significant remarks including- variable cloud height, variable visibility, precipitation beginning/ending times, rapid pressure changes, pressure change tendency, wind shift, peak wind.

RADIOSONDES (WEATHER BALLOONS) ARE USED TO MAKE UPPER AIR OBSERVATIONS. THE NWS OPERATES 92 STATIONS IN THE U.S. AND OBSERVATIONS ARE MADE TWICE DAILY. THE BALLOONS WILL ASCEND TO 115,000 FEET. WHEN THE BALLOON BURSTS, A PARACHUTE WILL DEPLOY TO GET THE INSTRUMENT PACKAGE TO EARTH SAFELY. APPROXIMTELY 20% ARE RETURNED EACH YEAR.

WEATHER SATELLITES POLAR ORBITING SATELLITES (POES): ADVANTAGES – ORBIT AT APPROXIMATELY 520 MILES ABOVE THE SURFACE, GIVE DETAILED IMAGES, GIVE IMAGES OF THE POLAR REGIONS DISADVANTAGES - PATH OF SATELLITE CHANGES WITH EACH ORBIT GEOSTATIONARY SATELLITES (GOES): ADVANTAGES: ALWAYS LOCATED IN THE SAME SPOT, SO CAN CONTINUOUSLY OBSERVE MOTIONS OF CLOUDS DISADVANTAGES: LOCATED APPROXIMATELY 22,000 MILES ABOVE SURFACE, SO LESS DETAIL, AND NO VIEW OF POLAR REGIONS

WEATHER IS THE MOVEMENT OF AIR MASSES DRIVEN BY THE SUN. EACH OF THESE AIR MASSES ARE AT DIFFERENT TEMPERATURES AND CONTAIN DIFFERENT AMOUNTS OF MOISTURE. ONE AIR MASS WILL INFLUENCE AND BE INFLUENCED BY OTHER AIR MASSES. IT IS A VERY COMPLEX SYSTEM. SO COMPLEX THAT CHAOS THEORY TALKS ABOUT THE “BUTTERFLY EFFECT.”

ALL WEATHER TAKES PLACE IN THE TROPOSPHERE. THE TROPOSPHERE IS 10 TO 14 KM HIGH. IT CONTAINS ABOUT 75% OF THE MASS OF THE ATMOSPHERE AND 99% OF THE WATER VAPOR. THE SUN PROVICES THE ENERGY. BUT THE CAUSE IS UNEVEN HEATING OF THE EARTH’S SURFACE. THE SURFACE IS HEATED UNEVENLY FOR THREE REASONS: 1.TILT OF THE EARTH ON ITS AXIS. 2.NIGHT ON ONE SIDE AND DAY ON THE OTHER. 3.DIFFERENT SURFACE MATERIALS HEAT AT DIFFERENT RATES.

THIS ENERGY IS NOT EQUALLY DISTRIBUTED OVER THE SURFACE OF THE EARTH. THE EARTH’S AXIS IS TILTED AT 23.5 o RELATIVE TO OUR ORBIT ABOUT THE SUN.

THIS GIVES US OUR SEASONS.

DIFFERENTIAL HEATING ALSO LEADS TO WINDS AND WIND PATTERNS ON BOTH A LOCAL AND A GLOBAL LEVEL.

CORIOLIS EFFECT CAUSES WINDS TO BEND TO THE RIGHT IN THE NORTHEN HEMISPHERE AND TO THE LEFT IN THE SOUTHERN HEMISPHERE.