As of 1000 Zulu, there is a low pressure trough over the Oklahoma and Texas panhandle area, which is forecast to move eastward into central southwestern Oklahoma by 0400 Zulu. A 4-digit data group shows the wind direction in reference to true north, and the windspeed in knots. A weather depiction chart details surface conditions as derived from METAR and other surface observations. The amount of sky coverage is reported in eighths of the sky from horizon to horizon. These conditions will be beginning after 0200 Zulu and will continue beyond the forecast scope of this SIGMET of 0530 Zulu. This is the most comprehensive book on aviation weather ever written. Alaska identifiers always begin with the letters “PA” and Hawaii identifiers always begin with the letters “PH.” A list of station identifiers can be found at an FSS or NWS office. A variety of different forecast products are produced and designed to be used in the preflight planning stage. Dimension of echo pattern—The dimension of an echo pattern is given when the azimuth and range define only the center line of the pattern. The Convective SIGMET is for an area from Kansas to Oklahoma to Texas, in the vicinity of a line from Goodland, Kansas, to Childress, Texas. Surface aviation weather observations (METARs) are a compilation of weather elements of the current weather at ground stations across the United States. The temperature is given in degrees Celsius. Terminal radar ensures pilots are aware of wind shear, gust fronts, and heavy precipitation, all of which are dangerous to arriving and departing aircraft. The valid time for the chart is printed on the lower left-hand corner of each panel. Numbers within these areas give the height of the turbulence in hundreds of feet MSL. Dewpoint—Dewpoint is given in degrees Fahrenheit. Other helpful information is whether the flight is visual flight rule (VFR) or instrument flight rule (IFR), aircraft identification and type, departure point, estimated time of departure (ETD), flight altitude, route of flight, destination, and estimated time en route (ETE). Next Topic → Topic Surface / Prog Charts Topic Progress: Surface Analysis and Prognostic Charts Surface analysis and Prog charts are my favorite way to get a big picture view of what the weather will be doing over the next few hours and into the next few days even. It calls for occasional moderate or greater clear air turbulence between 28,000 and 35,000 feet due to the location of the jetstream. Station Identifier—Each station is identified by a four-letter code as established by the International Civil Aviation Organization (ICAO). The higher the number, the greater the intensity. Each AIRMET bulletin has a fixed alphanumeric designator, numbered sequentially for easy identification, beginning with the first issuance of the day. The broadcasts include advisories such as AIRMETS, SIGMETS, convective SIGMETS, and urgent PIREPs. Typically, weather charts show the movement of major weather systems and fronts. There are three types of weather observations: surface, upper air, and radar. working in collaboration with NCEP. Because of the increasing need for worldwide weather services, foreign weather organizations also provide vital input. Cell movement—Movement is only coded for cells; it will not be coded for lines or areas. If the wind varies more than 60° and the windspeed is greater than 6 knots, a separate group of numbers, separated by a “V,” will indicate the extremes of the wind directions. *urxqg 6fkrro &uhdwhg e\ 6whyh 5hlvvhu.qrz 86 7lph =rqhv frqwlqhqwdo 367 067 &67 (67 )/ 72 7\shv ri 7lph &lyloldq /rfdo $0 dqg 30 It will not show areas of clouds and fog with no appreciable precipitation, or the height of the tops and bases of the clouds. It is the pilot’s decision whether or not to continue the flight under VFR, but this advisory should be weighed carefully. The types of clouds, specifically towering cumulus (TCU) or cumulonimbus (CB) clouds, are reported with their height. Direct User Access Terminal Service (DUATS). 201: IFR Low Enroute Charts Explained | Basics Part 1 - … Temperatures below 0°C are preceded by the letter “M” to indicate minus. Pilots remain the only real-time source of information regarding turbulence, icing, and cloud heights, which is gathered from pilots in flight, through the filing of pilot weather reports or PIREPs. Area forecasts are typically disseminated in four sections and include the following information: 1. 2. Figure 12: Intensity levels and contours, and precipitation type symbols. Type of Report—There are two types of METAR reports. Next, the dimension of this echo is given as 20 nautical miles wide (10 nautical miles on either side of the line defined by the azimuth and range). (1 is light and 6 is extreme.). 1. If necessary, it can be referenced later to file or amend a flight plan. The High-Level Significant Weather Prog, encompasses airspace from 25,000 feet to 60,000 feet pressure altitude over the conterminous U.S., Mexico, Central America, portions of South America, the western Atlantic, and eastern Pacific. 8. The information contained in this section may include wind data, variable visibility, beginning and ending times of particular phenomenon, pressure information, and various other information deemed necessary. A service specifically designed to provide timely enroute weather information upon pilot request is known as the enroute flight advisory service (EFAS), or Flight Watch. It also notes that these conditions are forecast to continue beyond 2000 Zulu. Each forecast is valid for 2 hours. The weather depiction chart is prepared and transmitted by computer every 3 hours beginning at 0100 Zulu time, and is valid at the time of the plotted data. It should be noted that when information is given in the area forecast, locations may be given by states, regions, or specific geological features such as mountain ranges. Adverse Conditions—This includes information about adverse conditions that may influence a decision to cancel or alter the route of flight. Figure 2: Descriptors and weather phenomena used in a typical METAR. At times, RVR, or runway visual range is reported following the prevailing visibility. This is a special report that can be given at any time to update the METAR for rapidly changing weather conditions, aircraft mishaps, or other critical information. We Review Rod Machado’s latest eLearning Course, “Understanding Aviation Weather.” I don’t know about you, but when I was first studying for the private pilot written exam, it was weather, not navigation or anything else, that I dreaded the most.I clearly remember reading the same page on fronts four or five times without retaining any of it. Weather charts are graphic charts that depict current or forecast weather. This is an important planning element for most flights. Forecast Visibility—The forecast visibility is given in statute miles and may be in whole numbers or fractions. An aviation routine weather report, or METAR, is an observation of current surface weather reported in a standard international format. A “Z” is appended to the end of the time to denote the time is given in Zulu time (UTC) as opposed to local time. Statements made here regarding height are given in MSL, and if given otherwise, AGL or CIG (ceiling) will be noted. An AIRMET includes forecast of moderate icing, moderate turbulence, sustained surface winds of 30 knots or greater, widespread areas of ceilings less than 1,000 feet and/or visibilities less than 3 miles, and extensive mountain obscurement. Sky Cover—The station model depicts total sky cover and will be shown as clear, scattered, broken, overcast, or obscured/partially obscured. It does, however, contain several limitations for the usage of the chart. Visibility—The prevailing visibility (3/4 SM) is reported in statute miles as denoted by the letters “SM.” It is reported in both miles and fractions of miles. 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