AOPA Pilot Magazine - March 1958 - (Page 74) Weather preceded the study, every weather map i the groupÑmor than 20,000 of them n bore a strong resemblance to one phase of only 11 basic sequential pat- - basic weafher patterns were directly mtluenced by the position of certain wanipermanent pressure features around the globe, located roughly along Latitude 30* north8. These semi-permanent pressure features tend to move with the m; terns. 2. In the Northern Hemisphere, t e that it, northward in the aununer, southward In the winter. The Krick people point out (hat for tile North American cm&hmt the controlling pressure feature la a high pressure cell known as the "East P&ci%c High," centered aft the Pacific coast. The clockwise winds around this high tend to act as steersmen for all a t o m e n our continent from the Pacific on the wings of the prevailing westerly winds. The point of entry into the continent te a vital factor in the path cyclonic weather syaterns will follow aa they travel eastward across the earntry* Faced with forecasting this point o entry from the position of the f East Pacific High, the Krick group developed a method by which the aver~ g position of the high for any given e month could be projected into the fntore. It was thia projection, plm the use o f an "analogue" technique, or the process of comparing present weather with similar weather patterns in the paat, which was battletested by Krick for the D-Day forecast of World War II and many other forecasts made for the militery during the war. However, as e r y as 1940, Trick and al his associates realized the limitations of any foxecasttng technique baaed on only a monthly mean position of the Pacific High. A method waa needed that would determine the Sat& position of the high, f t ~ well as other pertinent features of the atmospheric pressure patterns contrelbg the weather. It was at that time they began to look forward to the day when elec- KM, Z A @ 1957 SPECIAl PRODUCTS DIVISION, GLOBE INDUSTRIES, INC. 125 Sunrise Place, Dayton 7, Ohio ironic computers would mftke quick work of the myriad equations necessary to predict the position of this weather steersman and other aspects of the p e a sure patterns on a daily lasis. After the eftd o f World War H, Kxick and the entire meteorology staff st CalTech resigned to devote their full-time to development of their forecasting techniques. The answer to their manpower problem appeared in the form off a Bern. ingtoa Rand Univac 1 0 This el* 2. tronic computing aystem i capable of s solving the same munber of equations in lees than half an hour that formerly 1 required the time of one man for three months, Tida meant that, for the first time, the daily position of the East Pacific High cell and all other features of the atmosphere could be computed far enough i advance to make a TOOK n dependable and objective king-range forecast practical, Owe the computer solutions identify the dally positions of the East Pacific High, and other pressure configurations, for a period in the future, it Is then possible to establish the basic weather taehonntw indicator of rià t y p eom~hoft to^raduu currant to awn*^ ttà hdl- Etptlally mod* far u~ with a çti(wnAciw.Drtwfrome%jb influencing the continent. These weather types and their asaociatod highs and lows then permit lorecaatem to predict the weather m s likely to ot occur & any given day in the tutors a I t any location on the continent. Readers of The PILOT are invited to participate in the testing of this new step in aviation weather forecasting1 and make auggestiona as to what other general weather information would he helpful. The AOPA Weatfaercasts are intended to be of value to you sad, within certain prescribed limits diacussed earlier i this article, to be acn curate. Your observations as to their accuracy and dependability in your area will be of value to the AOPA Weathercast department and Dr. Krick and his &ittea. Let ua hear from you. Send yaw comments to the editors. ENS types THE AOPA PILOT
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