Atmospheric Sciences 101 Weather Review sheet for Midterm 2 These questions are intended as a guide to concepts to help study for the second midterm on 18 November These are not the exact questions which will appear on the midterm nor is it necessarily all inclusive you are still advised to go over the notes and the homework This sheet will not be collected for a grade Partial answers and hints will be posted on Tuesday 16 November For most questions you should be able to come up with a one sentence answer using terms and concepts from the class 1 What is a front 2 What are the four types of fronts What symbols are used to represent each of these on a surface weather map 3 Where in relation to the fronts is precipitation likely to occur 4 What do the vertical cross sections of each type of front look like 5 What are the typical weather observations during frontal passage for the two basic kinds of front 6 What kinds of clouds are produced by each kind of front 7 What is a common relationship between troughs ridges aloft and lows highs at the surface 8 Why is it generally cloudy in the vicinity of a low pressure area and sunny in the vicinity of high pressure 9 What are long and short waves on an upper level chart How do they differ 10 Consider a large column of air say 500 km across What happens to the vorticity rate of spin of this air if it is stretched vertically and is pulled inward like a figure skater bringing in her arms 11 Give the complete definitions for the following variables their units if they have any and what they represent a humidity b water vapor pressure c saturation vapor pressure d relative humidity e dew point temperature 12 Describe the relationship between saturation vapor pressure and temperature 13 Why is relative humidity not a very useful variable for specifying the amount of moisture in the air 14 What is the typical diurnal change in relative humidity keeping in mind that the amount of water vapor in the air does not change rapidly over a 24 hour period 15 What are condensation nuclei and ice nuclei 16 What is fog and how is it defined 17 List the four different types of fog how they form and an example of each 18 Why can you see your breath on cold mornings 19 Clouds grab bag a Name the four basic cloud types For each of these cloud types b What are their visual characteristics c What is their typical composition i e ice crystals or water droplets d What altitude are they typically observed at 20 What is the moist adiabatic lapse rate give a definition and a value 21 Why is the moist adiabatic lapse rate less than the dry adiabatic lapse rate 22 What are the three cases of atmospheric stability Give a typical value of the lapse rate for each What types of clouds would we expect in each of these 23 Why are absolutely unstable environmental lapse rates uncommon Where might we find an absolutely unstable environment 24 What are the common lifting processes which form clouds 25 Someone reports seeing a flying saucer east of Mt Rainier What is the most likely explanation for what they saw 26 What is the size difference between condensation nuclei cloud droplets and raindrops 27 How are cold and warm clouds defined with respect to growth of hydrometeors 28 Describe briefly how droplets grow in warm clouds 29 Why will ice particles grow more rapidly than super cooled droplets in the mixedphase region of a cold cloud 30 Name four types of precipitation 31 What type of cloud and process is needed to make hail 32 Why do we not expect hail to fall from stratus clouds 33 Why would a nimbostratus cloud have steadier precipitation than a cumulonimbus cloud 34 What causes a sea breeze to form How are sea breezes similar to and different from monsoons 35 What causes a valley breeze to form A mountain breeze 36 Which would be more strongly affected by Coriolis forces a mid latitude cyclone or a severe thunderstorm Why 37 Which direction does the surface wind typically come from in the Tropics 38 How do west winds along the equator in the central Pacific help promote El Nino 39 What effect does El Nino have on the location of thunderstorms in the ITCZ upwelling off of Peru and temperatures in the eastern equatorial Pacific 40 Give one similarity and one difference between coastal and equatorial upwelling 41 What is the ITCZ What pattern of surface winds causes it 42 In what season is the equator to pole temperature gradient the greatest When would the jet stream be the strongest How are these two related 43 At which latitudes are upward air motions dominant Downward 44 How can we identify where the jet stream is on an upper level chart e g a contour plot of 500 mb surface heights 45 At what height above the surface is the jet stream usually found 46 Why do airplanes try to avoid flying through clouds slightly below 0 deg C 47 A radar just north of Seattle does not pick up any precipitation southwest of the Olympic mountains However observers there are reporting long periods of heavy rain What is going on 48 Describe some effects of the positive and negative phases of the Pacific Decadal Oscillation How is it related to snowpack in the mountains 49 A long wet winter brings lots of snow in the mountains A weekend in March suddenly sees highs in the mid 70s across much of western Washington up into the Cascades and even some rain in the mountains Great right What problem might this create 50 Is the number of weather observations that goes into each daily computer based global weather forecast on the order of 1000 1 000 000 or 1 000 000 000 51 For each of the following stability situations absolute instability conditional instability and absolute stability answer the following questions Give a typical value of the environmental lapse rate What would happen to a dry parcel that is lifted A saturated one What kind of clouds and or weather would we expect to find