Thunderstorms

[Music] the time it had taken to train those six Pilots the time it had taken to build the storms looked very much like this not prop rled may be as dangerous as a burst of machine gun bullets from the nose of an enemy plane in order to safely fly through thunderstorm areas knowledge of how they are formed is essential there are two general types of thunderstorms frontal thunderstorms and air mass thunderstorms air mass thunderstorms result when the sun heats a land surface this heating action causes air to rise and cool these storms occur over land areas during the afternoon and early evening hours they dissipate during the night due to the cooling of the surface cold air moving out over a warm body of water will produce the same type of storm storms formed in this manner are not so violent and do not extend to as Great Heights as those formed by the sun's action over land they're just as common at night as during the day as the temperature of the water remains relatively constant both day and night air mass thunderstorms also occur when air is lifted up the mountain slope thunderstorms resulting from this cause or winds Prevail during many a year they may be isolated over a given mountain peak quite General along a mountain range these storms extend to Great Heights and are usually violent frontal thunderstorms occur when a wedge of cold air moves into a region of warm mer air the cold air acts as an inclined plane just as the windward side of Hills or mountains here again the warm air is forced up and cooled thunderstorms formed by this method are generally concentrated along a line which may extend for many hundreds of miles although the storm line appears to be solid in reality it is a series of individual thunderstorms closely knitted together with other clouds with no visible space between the basic characteristics of all thunderstorms are the same the up and down drafts of air cause great turbulence they are more violent in front than in the rear of the storm Heavies along the edges of these currents of air cause the external cauliflower appearance of the cloud the Anvil top is produced by the spreading out of the vertical currents when they reach their maximum height the ahead of the storm and the drafts in the storm cause a roll cloud at the base of the Leading Edge variable and shifting surface winds Prevail the thunderstorm is a real weather Factory rain hail and lightning are formed in its cold turbulent regions the raindrops which are caught in the updrafts and carried into the freezing Zone become ice they continue to grow in size in the freezing area until too heavy to be suspended Then Fall as hail hail Stones vary greatly in size the average size is that of a pee however in very rare cases they may be as large as baseballs turbulence causes the rain droplets to be broken into many parts this disintegrating action results in the building up of static electric charges in the cloud when these charges are great enough lightning occurs these electrical discharges may be observed as horizontal lightning or as vertical light darkest area under the storm is the region of heaviest rain and marks the Storm Center the rain causes low clouds to form and reduces ceiling and visibility hail is sometimes encountered in The Heavy Rain the more frequent the vertical lightning in this area the more violent the storm thunderstorms vary greatly in size the smaller ones which in reality are merely overgrown showers are from 12 to 15,000 ft high and present no serious Hazard to Flying the larger storms vary from 30,000 up to 60,000 ft these are the dangerous types they vary in diameter from 5 to 25 miles the most violent activity occurs in the lower 2/3 of the storm cloud for example if it is 30,000 ft from the base to the top of the cloud the greatest turbulence is in the lower 20,000 ft the intensity of the storm is dependent upon the distance from the base of the cloud to the freezing level the greater this distance the more violent the storm in the higher latitudes the freezing level is closer to the Earth's surface resulting in less violent individual thunderstorm activity with lower tops in the lower latitudes and as the equator is approached the freezing level becomes farther and farther from the Earth's surface resulting in higher tops and more violent individual thunderstorm activity at any given latitude thunderstorms vary in size with the seasons in the summer months they reach their maximum height in the fall and spring their tops are lower due to the freezing line being closer to the Earth's surface and the Anvil top is not so readily apparent the freezing level is closer to the Earth during the cold seasons of the Year therefore thunderstorms are less frequent in summary thunderstorms Tower to Great Heights and have a spreading Anvil top the region of greatest violence is the lower 2/3 of the cloud it has an external cauliflower flower appearance with a roll cloud at the Leading Edge at the base a dark area of rain appears underneath the core of the storm these identifying features are not always so easy to see they may be masked by other clouds low clouds forming underneath May hide the roll cloud and the dark rain area and the base of the real storm shelves of clouds sometimes extend for many miles out in front these clouds May hide the top of the storm from a low-flying plane these same clouds May hide the base of the storm from a high flying plane although these shelves of clouds conceal the real storm centers they do indicate to the pilot that he is at the front of the disturbance the Anvil top will lean in the direction the storm is moving air mass thunderstorms may be isolated and scattered over a wide area they also may be grouped in a compact Bunch covering many hundreds of square miles air mass thunderstorms may be located over an individual mountain peak or extend in a solid line along a mountain range frontal thunderstorms generally exist as a solid wall extending for many hundreds of miles thunderstorms are more varied in appearance size and shape than our human beings here are some actual conditions as they appear in nature this cloud has not built up to the thunderstorm stage however it shows evidence of considerable turbulence as indicated by the boiling effect an isolated thunderstorm in the last stages of development within half an hour rain began to fall and lightning discharges were observed an example of an isolated well defined thunderstorm that is formed over an island the dark area underneath is heavy rain this storm has more violence and vertical growth than if it had formed over the Open Sea as it has formed over the island it will have a tendency to dissipate after Sunset a towering thunderstorm over the Open Sea the light behind clearly defines the edges of the cloud an example of a thunderstorm partly masked by surrounding clouds the center of the storm is to the right of the scene where the heavy rain is occurring thunderstorms are many times masked by surrounding clouds this storm is approaching as indicated by the sh of clouds extending out in front this is a line of storms with the sun shining through them from behind therefore the storm centers show up darker than masking clouds storms with no light behind them are not so clearly defined and it is more difficult to recognize and avoid the turbulent areas this cumulus cloud is building into a thunderstorm rain is beginning to fall from the base and the top is forming into the Anvil shape a line of clouds with widely scattered thunderstorm activity at this stage the storm would not present a serious Hazard to a properly conducted flight this is a condition where the outer roll cloud on the Leading Edge of a line of storms is very near the Earth's surface and too low to fly under violent turbulence would be experienced in this region and it would be inadvisable to attempt flying through this area the boiling effect in these clouds indicates great turbulence the center of the storm is indicated by the rain area on the right of the scene this is how a storm looks from a low level with the rain and ragged clouds at the base clearly visible a cloud formation called mamatas it is generally a part of the underside of the deck of clouds projecting out in front of the storm when the mamatas clouds precede thunderstorm activity the storm is usually severe this is a line of thunderstorms with welldefined Anvil tops taken from an altitude of 18,000 ft the storms are some 130 M away and the Anvil Tops Reach an altitude of 35,000 ft this shows how storm tops may be clearly defined while the bases are hidden from a high flying plane by surrounding cloud this is a fully developed thunderstorm with the veil top spread into the Anvil shape the position of the top indicates a movement from right to left here the veil top is spread to a greater degree and does not have the characteristic Anvil shape but indicates a thunderstorm at its maximum intensity a storm line over water the veiled tops identify the well- defined thunderstorm activity the main storms however are massed by surrounding clouds thunderstorms at night have the same general characteristics as those in the daytime but present a greater Hazard du to reduced visibility the storm centers are many times revealed by lightning flashes the preponderance of vertical Strokes is an indication that the storm is being approached from the front these lightning flashes will all feel the height of the storm base above the surface the more frequent the vertical flashes the more violent the storm horizontal lightning flashes create less violent the presence of this type of lightning is usually an indication that the back of the storm is being approach lightning flashes will many times reveal the type of surface beneath the storm this is especially useful where rugged country is concerned high level lightning flashes within the cloud frequently reveal the location of the top of as a pilot approaches the thunderstorm area the flight procedure to be used will depend upon the type of storm the locality over which it lies the type of equipment the altitude and the mission to be performed the storm should be analyzed before the surrounding clouds are encountered as they might obscure the important characteristics study the situation thoroughly before making a decision whether encountering a single storm a group of storms or a line of storms the flight procedures are similar the pilot May circumnavigate the storm centers through a thin spot or clear area or fly at a low level underneath the base of the thunderstorm or fly at a high level over a Saddleback between storm tops always fly round isolated air mass thunderstor St do not try to save time by flying a straight course through the thunderstorms when they can be avoided by circumnavigation the added mileage and the time lost are of little consequence it is a good practice to fly around thunderstorms in mountainous regions when thunderstorms Prevail along Coastal mountain ranges a flight conducted a few miles to seaward will avoid this activity thunderstorms over Islands may be many thousands of feet higher than those associated with the Open Sea and should be circumnavigated a wall of thunderstorms caused by a front presents many problems when applying the rule of circumnavigation the storm line is generally too long to fly around it should be kept in mind however that the storm front is a series of individual thunderstorms closely kned together by intervening clouds it is often possible therefore to fly between these storm centers through holes or thin spots sometimes the hole is obvious with blue sky on the other side and presents no problem to circumnavigation in some cases it is impossible to see through the hole but there is definite evidence of thinness in this case determine the direction in which the line of storms is moving and head in at a right angle this will reduce flying time in the storm to a minimum after you have once set your course and started through don't turn around on account of turbulence rain or hail this will result in flying through the same conditions twice there is also the added Hazard of becoming lost it does not take long to fly through if a straight course is maintained a pilot approaching a line of thunderstorms at a low altitude can fly underneath their base if circumstances permit this procedure is recommended when flying over flat terrain or the Open Sea in determining a course underneath the storm centers can be identified by the dark rain areas here visibility is reduced and lightning flashes are frequent therefore it is preferable to conduct the flight through the clear areas between storm centers lightning is of no serious concern when flying an all metal closed cockpit airplanes as the craft acts as a perfect conductor however bright flashes may cause the pilot to be temporarily blinded if lightning strikes an open cockpit airplane it might injure the pilot and cause structural damage to the craft the turbulence under thunderstorms May Place heavy stress on aircraft and the inexperienced instrument pilot may have have difficulty controlling his Planes the closer you fly to the surface of the Earth the less turbulent it will be a good rule to follow is to fly 13 of the distance from the surface to the base of the cloud for example if the cloud is determined to be 3,000 ft above the surface fly at 1,000 ft on approaching the front of the storm an updraft will be encountered under the roll cloud region strong up and down drafts will be experienced at the core of the storm a downdraft is usually encountered then an updraft May lift the plane toward the base of the storm finally there is a downdraft before breaking into the clear in a flight under the storm the higher the flight level the rougher the trip care must be taken to prevent being lifted into the cloud forming the storm base when flying under the storm from the rear the pilot will experience a downdraft first this leads to the following rule when entering a storm from the rear enter at a higher level than you would if entering from the front when visibility is bad underneath and contact flight cannot be maintained it is inadvisable to fly under the storm in the case of thunderstorm conditions along mountain ranges never attempt to fly underneath unless a good ceiling exists and the visibility is such that Peaks and ridges are clearly defined Never Land at an airport when the wind shifts in advance of a thunderstorm is approaching the field turbulence and shifting surface winds make this a hazardous procedure since thunderstorms move at a speed of from 10 to 30 knots it is often possible to wait until the Storm Center has passed before landing when high level flight is anticipated the pilot should seek a high level before approaching the storm getting on top of the protruding shelf of clouds around the storm this will give him an opportunity to inspect the storm line and select his course when thunderstorms are associated with r rough terrain high level flight is preferable this procedure is the safest in cases where the pilot is not familiar with mountain ranges and mountain peaks when flying at a high level it is inadvisable to fly underneath overhanging clouds associated with the Anvil tops as hail is often encountered in these regions try to pick a spot that has no overhanging clouds lines of thunderstorms over land generally extend to Greater Heights than those over the Open Seas 15,000 ft will usually top the saddle backs of a storm line over the sea in some cases it is impossible I to establish a path which will conform to the three basic flight procedures when you are faced with this problem there are two courses open fly between storm areas as high as possible to miss the greatest turbulence or fly between storm areas as low as possible avoiding the roll clouds and staying safely above the highest terrain here's a report of a pilot who encountered a storm and could not establish any one of the three basic flight procedures and was forced to fly through took off from HomeField on an important mission to a base in the Canal Zone forecast of thunderstorm conditions ahead early in the evening the predicted conditions were encountered a wall of storms appeared extending for hundreds of miles to the east and west mountains paralleled the coast from north to south and extended up into the clouds at 14,000 ft so later course out to sea the storm extended down close to the water and appeared violent preventing F under it could not be flown around so climbed trying to top it at 16,000 ft the ship became sluggish due to heavy load and as the cloud still towered up Beyond this point it was apparent that that the plane would not be able to get over there was now no other course but to go through chose a spot which appeared to be between two storm centers checked instruments reduce flying speed and headed in at a right angle turned on cockpit lights to avoid temporary blindness from anticipated light flashes first updraft was not strong then encountered very heavy turbulence rain fell in torren visibility dropped to zero was tempted to turn back in search of a better point of entry but did not want a risk becoming lost and add to flying time in the storm frequent lightning Flash some bolts probably struck the craft but discharges were conducted off as the ship was an all metal closed cockpit jum suddenly the plane was rocked by a violent downdraft indicating Midway point of the storm ran into hail but fortunately it was soft and splattered against the Ship Without damage after emerging from the strongest turbulence a display of St Elmo's Fire was encountered static electricity was building up on the plane flashes of light jumped across the surfaces of the windshields streamers of electricity played up and down the wings and at the same time fiery blue green circles formed on the periphery of the propellers cut flying speed further to avoid an electric discharge which might damage the radio shortly afterward broke out into the clear rest of flight was uneventful in summary the pilot headed seaward when he encountered a storm condition which had build up along the coastal mountains for at ca he would find the intensity of the storm less severe he did not attempt to fly under the condition since it lay almost on the surface and appeared very violent at that point he was unable to go around the storm wall since the front extended for several hundred miles the storm was too high to fly over so he chose a thin area when forced to fly through to avoid the cores of any of the storms he headed in at a right angle this was for the purpose of flying a straight course through the storm and reducing his flying time within it to a minimum he turned his cockpit lights on and kept his eyes on the instrument panel to avoid temporary blindness when lightning flashed close to the planes although tempted to turn back upon encountering the heaviest turbulence the pilot chose to continue on his original course knowing that he might otherwise become lost and his flying time in the storm be greatly increased when he found static electricity building up on the plane he slowed his speed to reduce the possibility of a discharge which would produce a blinding Flash and possibly destroy radio communication experience has taught that the safest course is to stay away from thunderstorms however due to the urgency of many present day missions it is often necessary to break this rule the modern airplane is the best for its purpose that human Ingenuity can devise when flying through thunderstorm conditions the pilot must have confidence in his knowledge of the structure of thunderstorms and confidence in his equipment remember it is the pilot that loses his head and not the plane