DOCSLIB.ORG

Ront November-Ddecember, 2002 National Weather Service Central Region Volume 1 Number 6

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

The ront November-DDecember, 2002 National Weather Service Central Region Volume 1 Number 6 Technology at work for your safety In this issue: Conceived and deployed as stand alone systems for airports, weather sensors and radar systems now share information to enhance safety and efficiency in the National Airspace System. ITWS - Integrated Jim Roets, Lead Forecaster help the flow of air traffic and promote air Terminal Aviation Weather Center safety. One of those modernization com- Weather System The National Airspace System ponents is the Automated Surface (NAS) is a complex integration of many Observing System (ASOS). technologies. Besides the aircraft that fly There are two direct uses for ASOS, you and your family to vacation resorts, and the FAA’s Automated Weather or business meetings, many other tech- Observing System (AWOS). They are: nologies are at work - unseen, but critical Integrated Terminal Weather System MIAWS - Medium to aviation safety. The Federal Aviation (ITWS), and the Medium Intensity Intensity Airport Administration (FAA) is undertaking a Airport Weather System (MIAWS). The Weather System modernization of the NAS. One of the technologies that make up ITWS, shown modernization efforts is seeking to blend in Figure 1, expand the reach of the many weather and aircraft sensors, sur- observing site from the terminal to the en veillance radar, and computer model route environment. Their primary focus weather output into presentations that will is to reduce delays caused by weather, Gust fronts - Evolution and Detection Weather radar displays NWS - Doppler FAA - ITWS ASOS - It’s not just for airport observations anymore Mission Statement To enhance aviation safety by Source: MIT Lincoln Labs increasing the pilots’ knowledge of weather systems and processes Figure 1. ASOS is an important component in the FAA’s Integrated Terminal Weather and National Weather Service System. ITWS is a weather monitoring and short range prediction system designed to products and services. aid air traffic controllers and pilots for the safe and efficient movement of air traffic. 1 minal Doppler Weather Radar (TDWR), an ASR-9 Weather System Pro-cessor (WSP), or ITWS, but could benefit from the higher level of safety that a MIAWS system would provide. MIAWS seeks to provide weather coverage to these air- ports by using existing, nearby sensors. MIAWS, an enhancement of NEXRAD, has an initial objective of pro- viding real-time display of storm posi- tions and storm tracks using NEXRAD product data as the input to a weather ser- vice processor product generation and display system. Wind speed and wind gust information is provided through ASOS/AWOS input to the LLWAS - relo- cation/sustainment anemometer network. The NEXRAD reflectivity data will be displayed in the NWS 6-level thresholds. Storm position and motion vectors show- ing direction and speed of storm cells, will provide extrapolation lines with 10 and 20 minute leading edge positions. Source: MIT Lincoln Labs The system will also show airport wind vectors depicting wind speed and direc- Figure 2. ITWS blends information from several technologies to give controllers an tion, and any current airport runway integrated assessment of storm impact. impact alerts. especially at the busiest airports. The Alert System (FAA) The main users of this information, integration of these many airport and NLDN - National Lightning as with ITWS, will be controllers, pilots, weather systems and sensors into a cohe- Detection Network and traffic managers. Two operational sive and easily understandable display MDCRS, ACARS - Aircraft Reports prototype systems have been providing will greatly enhance the safety of flight RVR - Runway Visual Range controllers with weather alerts at the operations within the usually busy termi- Sensors (later). Jackson International Airport, MS, and nal environment. Developed by MIT Lincoln The information is disseminated via Memphis, TN, since September 2000. color displays to pilots, controllers, and Two new MIAWS prototypes were sched- Integrated Terminal Weather traffic managers. uled to be installed at Little Rock, AR, System: According to Lincoln Laboratories, and Springfield, MO airports in the Laboratories, ITWS provides weather ITWS installation began at major airports Spring of 2002. products for air traffic automation sys- in 2001. Figure 3 shows end state deploy- tems by using data from FAA and ment goals. Lincoln Laboratory is contin- National Weather Service (NWS) sensors, uing to operate ITWS functional proto- aircraft reports, and NWS numerical types in Memphis, Orlando and Dallas/Ft. weather prediction to provide short-term Worth in order to increase the ITWS oper- forecasts (out to 30 minutes) for the ter- ational and meteorological database and minal area. See Figure 2. The FAA oper- to provide operational user benefits. ational users access the ITWS products The MIAWS program was estab- through a color situation display. ITWS Medium Intensity Airport Figure 3. ITWS will serve: provides information on microbursts, gust Weather System: fronts, tornadoes, storm location and 49 ATCTs, motion, hail, and winds at the airport ter- lished to develop a weather processing 37 TRACONs minal area. Besides ASOS and AWOS, and display system for airports with a 18 ARTCCs ITWS uses the following sensors: medium level of operations, but which 3 support facilities The areas served have the most season- TDWR -Terminal Doppler Weather lack the abundance of dedicated weather sensors found at larger airports. Its goal is wide thunderstorms and severe weather Radar (FAA) that affect air traffic and air safety. NEXRAD - Next-Generation to provide near-term, low-cost weather Weather Radar (NWS) information to these airports. According ASR-9 - Airport Surveillance Radar to the FAA, airports of this size have too (Sources: FAA and MIT Lincoln (FAA) few operations to justify the cost of a ded- Laboratories) For more information, visit www1.faa.gov/aua/ipt_prod/weather/ LLWAS - Low Level Wind Shear icated weather system such as the Ter- itws//menusys.htm 2 through the warm environment and lifts Wind shear detection by NEXRAD, the air to promote new convection along the outflow boundary. To a pilot with a ITWS and MIAWS very local view, things seem pretty Gust fronts and microbursts may show obvious, visual signs of benign, but what may well be depicted on their presence, but in the less obvious situations, ITWS and an ITWS or MIAWS terminal is a devel- oping wind shear event. MIAWS are enabling controllers to see the hidden dangers. In a line of thunderstorms composed If you think the thunderstorm season clouds as shown in Figure 4. of multiple cells, any number of storms ended, think again. The record thunder- These monsters are not the storms could be dissipating and producing out- storm event of November 10-11, 2002 you read about in wind shear accidents. flow boundaries. Where these boundaries spread destruction across a large portion Rather, storms of intensity level 3 have meet, new convection fires up thanks to of the southern and eastern U.S. Much of led to tragic accidents in years past the combined lift of the intersecting it occurred in the area where ITWS and because weak wind shear was not boundaries. MIAWS are being deployed. Judgement observed or detected by instruments on Radar reflectivity imagery, the type on this deployment appears rock solid. the field or by weather radar. shown most often on TV and on NWS Traditional pilot training inundates Decaying thunderstorms can leave web sites, may show an outflow boundary the students with ominous images of the sky mostly clear and the air cooler. as a thin curved line. See Figure 6. Note approaching thunderstorms. Gust fronts One would justifiably believe that the that the reflectivity diplay shows no are often marked with roll clouds or shelf danger has passed. echoes in the area south of the main storm A broader satellite imagery may give except for the thin curved line. METAR clues that the danger has not passed. As a reports from around the region show thunderstorm evolves from the mature southerly flow. However, between the stage to the dissipating stage, it becomes gust front and the main thunderstorm increasingly dominated by downdrafts northerly flow dominates. The subtle, and drops its cool rainfall. This cooler air stealthy wind shear event is well under- spreads out in all directions and forms way. what’s known as an outflow boundary. The curved line marks the region Convection is suppressed in this air and where the cooler and denser air is emerg- the sky clears. This scenario is depicted in ing. Doppler radar can detect these events Figure 4. Roll clouds form where the Figure 5. in regions where the radar beam is low warm inflow and cool outflow pass one The dark cloud-free circles mark the enough. another. These are the obvious “No Fly stabilized air. The cool air spreading out Figure 7 is a depicition of how this Zones” for thunderstorms. from the decayed thunderstorm acts like a event might occur if it were approaching cold front. The cooler, denser air moves a major airport. The main thunderstorm is New Convection Along Intersecting Boundaries Storm movement G us t Front Surface wind Gust front Outflow Boundaries movement Figure 5. When outflow boundaries (blue arrows) from near- Figure 6. Thunderstorm outflow called a gust front may produce by thunderstorms intersect, new convection can begin. The strong wind shear. Sometimes the gust front is visible on NWS radar data ingested into ITWS can provide clues about wind Doppler radar. ASOS observations would provide solid ground shifts associated with these outflows. truth to confirm the presence and strength of the outflow. 3 some distance away scans just at the top of this 1500 foot deep gust front, but the radar is still able to accurately detect any internal tight circulation, or large hail within the thunderstorm.
Recommended publications
  • A Real-Time System to Estimate Weather Conditions at High Resolution

    A Real-Time System to Estimate Weather Conditions at High Resolution

    12.1 A Real-Time System to Estimate Weather Conditions at High Resolution Peter P. Neilley1 Weather Services International, Inc. Andover, MA 01810 And Bruce L. Rose The Weather Channel Atlanta, GA the earth’s surface (the so-called current 1. Introduction1 conditions). b) We do not necessarily produce weather The purpose of this paper is to describe an observations on a regular grid, but at an operational system used to estimate current irregular set of arbitrary locations or points weather conditions at arbitrary places in real- that are relevant to the consumers of the time. The system, known as High Resolution information. Assimilation of Data (or HiRAD), is designed to generate synthetic weather observations in a c) In addition to producing quantitative manner equivalent in scope, timeliness and observational elements (e.g. temperature, quality to a arbitrarily dense physical observing pressure and wind speed) our system network. Our approach is, first, to collect produces common, descriptive terminology information from a variety of relevant sources of the sensible weather such as including gridded analyses, traditional surface “Thundershowers”, “Patchy Fog”, and weather reports, radar, satellite and lightning “Snow Flurries”. observations. Then we continuously synthesize these data into weather condition estimates at d) We do not strive to produce a state of the prescribed locations. An operational system atmosphere optimized for fidelity with based on this approach has been built and is Numerical Weather Prediction (NWP) commercially deployed in the United States. models. Instead, the system is optimized to produce the most accurate estimate of the In most regards, our approach is analogous to observed state at the surface that can be modern data assimilation techniques.
  • Geometric Characteristics of Clouds from Ceilometer Measurements and Radiosounding Methods

    Geometric Characteristics of Clouds from Ceilometer Measurements and Radiosounding Methods

    GEOMETRIC CHARACTERISTICS OF CLOUDS FROM CEILOMETER MEASUREMENTS AND RADIOSOUNDING METHODS Montserrat Costa Surós Dipòsit legal: Gi. 1888-2014 http://hdl.handle.net/10803/284084 http://creativecommons.org/licenses/by/4.0/deed.ca Aquesta obra està subjecta a una llicència Creative Commons Reconeixement Esta obra está bajo una licencia Creative Commons Reconocimiento This work is licensed under a Creative Commons Attribution licence GEOMETRIC CHARACTERISTICS OF CLOUDS FROM CEILOMETER MEASUREMENTS AND RADIOSOUNDING METHODS DOCTORAL THESIS Montserrat Costa Surós 2014 DOCTORAL THESIS GEOMETRIC CHARACTERISTICS OF CLOUDS FROM CEILOMETER MEASUREMENTS AND RADIOSOUNDING METHODS Montserrat Costa Surós 2014 Doctoral Programme in Experimental Sciences and Sustainability Supervisors: Josep Calbó Angrill José Abel González Gutiérrez Thesis submitted for the degree of Doctor of Philosophy by the University of Girona El Dr. Josep Calbó Angrill i el Dr. José Abel González Gutiérrez, professors titulars del Departament de Física de la Universitat de Girona, CERTIFIQUEN: Que aquest treball, titulat “Geometric characteristics of clouds from ceilometer measurements and radiosounding methods”, que presenta la Montserrat Costa Surós per a l’obtenció del títol de doctora, ha estat realitzat sota la seva direcció. I, perquè així consti i tingui els efectes oportuns, signen aquest document. Dr. Josep Calbó Angrill Dr. José Abel González Gutiérrez Girona, 29 de juliol de 2014. Un esforç total és una victòria completa M. Ghandi Acknowledgments First and the most important I would like to thank my supervisors Dr. Josep Calbó and Dr. Josep- Abel González for giving me the opportunity to begin my research career with them, which has led to this doctoral thesis, and for their guidance and support during these years.
  • AMOFSG/10-Sod 19/6/13

    AMOFSG/10-Sod 19/6/13

    AMOFSG/10-SoD 19/6/13 AERODROME METEOROLOGICAL OBSERVATION AND FORECAST STUDY GROUP (AMOFSG) TENTH MEETING Montréal, 17 to 19 June 2013 SUMMARY OF DISCUSSIONS 1. HISTORICAL 1.1 The tenth meeting of the Aerodrome Meteorological Observation and Forecast Study Group (AMOFSG) was held at the Headquarters of the International Civil Aviation Organization (ICAO) in Montréal, Canada, 17 to 19 June 2013. 1.2 The meeting was opened by Mr. Greg Brock, Chief of the Meteorology Section of the Air Navigation Bureau of ICAO, who extended a warm welcome to all the participants. Mr. Brock emphasized that this tenth meeting of the AMOFSG was likely to be the last of the group prior to the convening of an ICAO Meteorology (MET) Divisional Meeting in July 2014, to be held in part conjointly with the Fifteenth Session of the World Meteorological Organization (WMO) Commission for Aeronautical Meteorology (CAeM-XV). For this reason, Mr. Brock underlined the need for the group to work efficiently during its three days of deliberations, with a strong emphasis placed on determining whether proposals arising from each of the topics to be addressed were of sufficient maturity so as to reduce or eliminate entirely the need for significant further work and/or a meeting ahead of the MET Divisional Meeting. 1.3 The names and contact details of the participants are listed in Appendix A . Mr. Bill Maynard was elected Chairman of the meeting. The meeting was served by the Acting Secretary of the AMOFSG, Mr. Greg Brock, Chief, Meteorology Section. 1.4 The meeting considered the following agenda items: Agenda Item 1: Opening of the meeting; Agenda Item 2: Election of Chairman; Agenda Item 3: Adoption of working arrangements; Agenda Item 4: Adoption of the agenda; (41 pages) AMOFSG.10.SoD.en.docx AMOFSG/10-SoD - 2 - Agenda Item 5: Aerodrome observations; Agenda Item 6: Forecasting at the aerodrome and in the terminal area and ATIS requirements; Agenda Item 7: Deliverables; Agenda Item 8: Any other business; and Agenda Item 9: Closure of the meeting.
  • Fire W Eather

    Fire W Eather

    Fire Weather Fire Weather Fire weather depends on a combination of wildland fuels and surface weather conditions. Dead and live fuels are assessed weekly from a satellite that determines the greenness of the landscape. Surface weather conditions are monitored every 5-minutes from the Oklahoma Mesonet. This fire weather help page highlights the surface weather ingredients to monitor before wildfires and also includes several products to monitor once wildfires are underway. Fire Weather Ingredients: WRAP While the presence of wildland fuels is one necessary component for wildfires, weather conditions ultimately dictate whether or not a day is primed for wildfires to occur. There are four key fire weather ingredients and they include: high Winds, low Relative humidity, high Air temperature, and no/minimal recent Precipitation (WRAP). High Winds are the second most critical weather ingredient for wildfires. In general, winds of 20 mph or greater 20+ mph winds increase spot fires and make for most of the containment considerably more difficult. state Low Relative humidity is the most 30-40+ critical weather ingredient for wildfires mph winds and is most common in the afternoon when the air temperature is at its warmest. When relative humidity is at or below 20% extreme fire behavior can result and spot fires become freQuent. Watch out for areas of 20% or below relative humidity and 20 mph or higher winds à 20/20 rule! Extremely low relative humidity Warm Air temperatures are another values key weather ingredient for wildfires as warming can lower the relative humidity, reduce moisture for smaller dead fuels, and bring fuels closer to their ignition point.
  • Weather Charts Natural History Museum of Utah – Nature Unleashed Stefan Brems

    Weather Charts Natural History Museum of Utah – Nature Unleashed Stefan Brems

    Weather Charts Natural History Museum of Utah – Nature Unleashed Stefan Brems Across the world, many different charts of different formats are used by different governments. These charts can be anything from a simple prognostic chart, used to convey weather forecasts in a simple to read visual manner to the much more complex Wind and Temperature charts used by meteorologists and pilots to determine current and forecast weather conditions at high altitudes. When used properly these charts can be the key to accurately determining the weather conditions in the near future. This Write-Up will provide a brief introduction to several common types of charts. Prognostic Charts To the untrained eye, this chart looks like a strange piece of modern art that an angry mathematician scribbled numbers on. However, this chart is an extremely important resource when evaluating the movement of weather fronts and pressure areas. Fronts Depicted on the chart are weather front combined into four categories; Warm Fronts, Cold Fronts, Stationary Fronts and Occluded Fronts. Warm fronts are depicted by red line with red semi-circles covering one edge. The front movement is indicated by the direction the semi- circles are pointing. The front follows the Semi-Circles. Since the example above has the semi-circles on the top, the front would be indicated as moving up. Cold fronts are depicted as a blue line with blue triangles along one side. Like warm fronts, the direction in which the blue triangles are pointing dictates the direction of the cold front. Stationary fronts are frontal systems which have stalled and are no longer moving.
  • Clouds, Precipitation and Their Remote Sensing Intergovernmental

    Clouds, Precipitation and Their Remote Sensing Intergovernmental

    25.09.12 Clouds, Precipitation and their Remote Sensing Prof. Susanne Crewell AG Integrated Remote Sensing Institute for Geophysics and Meteorology University of Cologne Susanne Crewell, Kompaktkurs, Jülich24. 25 September September 2012 2012 Intergovernmental Panel on Climate Change (IPCC) www.ipcc.ch Nobel price 2007 IPCC Fourth Assessment Report (FAR), 2007: "Warming of the climate system is unequivocal", and "Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations". Aerosols, clouds and their interaction with climate is still the most uncertain area of climate change and require multidisciplinary coordinated research efforts. SusanneSusS sanna ne Crewell,Crewewellelll,K, Kompaktkurs,Kompakta kurs, JülichJülJüü ichchc 252 SeptemberSSeeptetetembembber 201220121 1 25.09.12 Why are clouds so complex? Cloud microphysical processes occur on small spatial scales and need to be parametrized in atmospheric models Cloud microphysics is strongly connected to other sub-grid scale processes (turbulence, radiation) Cloud droplets 0.01 mm diameter 100-1000 per cm3 Condensation nuclei Drizzle droplets 0.001 mm diameter 0.1 mm diameter 1000 per cm3 1 per cm3 Rain drops ca. 1 mm diameter, 1 drops per liter Susannesa Crewell, Kompaktkurs, Jülich 25 September 2012 Why are clouds so complex? From hydrometeors to single clouds to Einzelwolken to the global and cloud fields system Susanne Crewell, Kompaktkurs, Jülich 25 September
  • Operating Instructions Present Weather Sensor Parsivel

    Operating Instructions Present Weather Sensor Parsivel

    Operating instructions Present Weather Sensor Parsivel English We reserve the right to make technical changes! Table of contents 1 Scope of delivery 5 2 Part numbers 5 3 Parsivel Factory Settings 6 4 Safety instructions 7 5 Introduction 8 5.1 Functional principle 8 5.2 Connection Options for the Parsivel 9 6 Installing the Parsivel 10 6.1 Cable Selection 10 6.2 Wiring the Parsivel 11 6.3 Grounding the Parsivel 13 6.4 Installing the Parsivel 14 7 Connecting the Parsivel to a data logger 15 7.1 Connecting the Parsivel to the LogoSens Station Manager via RS-485 interface 15 7.2 Connecting the Parsivel to a Data logger via the SDI-12 Interface 17 7.3 Connecting the Parsivel to a Data Logger with Impulse/Status Input 21 8 Connecting the Parsivel to a PC 23 8.1 Connecting the Parsivel to Interface Converter RS-485/RS-232 (Accessories) 23 8.2 Connecting the Parsivel to the ADAM-4520 Converter RS-485/RS-232 (Accessories) 25 8.3 Connecting the Parsivel to Interface Converter RS-485/USB (Accessories) 26 8.4 Connecting the Parsivel to any RS-485 Interface Converter 27 8.5 Connecting the Parsivel for configuration via the Service-Tool to a PC 27 9 Connecting the Parsivel to a Power Supply (Accessory) 29 10 Heating the Parsivel sensor heads 30 11 Operating Parsivel with a Terminal software 31 11.1 Set up communications between the Parsivel and the terminal program 31 11.2 Measured value numbers 32 11.3 Defining the formatting string 33 11.4 OTT telegram 33 11.5 Updating Parsivel Firmware 34 12 Maintenance 36 12.1 Cleaning the laser’s protective glass
  • Rightsizing Project Nextgen IOC Sensor Assessment Summary AJP

    Rightsizing Project Nextgen IOC Sensor Assessment Summary AJP

    RightSizing Project NextGen IOC Sensor Assessment Summary AJP-6830 1 of 64 December 1, 2009 RightSizing Project NextGen IOC Sensor Assessment Summary TABLE OF CONTENTS EXECUTIVE SUMMARY ............................................................................................................ 3 1 INTRODUCTION ................................................................................................................ 4 1.1 Context and Motivation .....................................................................................................4 1.1.1 NextGen ......................................................................................................................4 1.1.2 4D weather cube ........................................................................................................4 1.1.3 Weather observation and forecast requirements to meet NextGen goals .................5 1.2 RightSizing Project Goals ....................................................................................................6 1.2.1 Assessment of Sensor Network ..................................................................................7 1.2.2 Identification of gaps based on functional and performance requirements ..............8 1.2.3 Development of master plan to meet NextGen weather observation requirements .8 1.3 Scope of this Report (FY 2009) ...........................................................................................8 2 PROGRAM MANAGEMENT AND SCHEDULE ......................................................................
  • Worldwide Marine Radiofacsimile Broadcast Schedules

    Worldwide Marine Radiofacsimile Broadcast Schedules

    WORLDWIDE MARINE RADIOFACSIMILE BROADCAST SCHEDULES U.S. DEPARTMENT OF COMMERCE NATIONAL OCEANIC and ATMOSPHERIC ADMINISTRATION NATIONAL WEATHER SERVICE January 14, 2021 INTRODUCTION Ships....The U.S. Voluntary Observing Ship (VOS) program needs your help! If your ship is not participating in this worthwhile international program, we urge you to join. Remember, the meteorological agencies that do the weather forecasting cannot help you without input from you. ONLY YOU KNOW THE WEATHER AT YOUR POSITION!! Please report the weather at 0000, 0600, 1200, and 1800 UTC as explained in the National Weather Service Observing Handbook No. 1 for Marine Surface Weather Observations. Within 300 nm of a named hurricane, typhoon or tropical storm, or within 200 nm of U.S. or Canadian waters, also report the weather at 0300, 0900, 1500, and 2100 UTC. Your participation is greatly appreciated by all mariners. For assistance, contact a Port Meteorological Officer (PMO), who will come aboard your vessel and provide all the information you need to observe, code and transmit weather observations. This publication is made available via the Internet at: https://weather.gov/marine/media/rfax.pdf The following webpage contains information on the dissemination of U.S. National Weather Service marine products including radiofax, such as frequency and scheduling information as well as links to products. A listing of other recommended webpages may be found in the Appendix. https://weather.gov/marine This PDF file contains links to http pages and FTPMAIL commands. The links may not be compatible with all PDF readers and e-mail systems. The Internet is not part of the National Weather Service's operational data stream and should never be relied upon as a means to obtain the latest forecast and warning data.
  • Weather Observations

    Weather Observations

    Operational Weather Analysis … www.wxonline.info Chapter 2 Weather Observations Weather observations are the basic ingredients of weather analysis. These observations define the current state of the atmosphere, serve as the basis for isoline patterns, and provide a means for determining the physical processes that occur in the atmosphere. A working knowledge of the observation process is an important part of weather analysis. Source-Based Observation Classification Weather parameters are determined directly by human observation, by instruments, or by a combination of both. Human-based Parameters : Traditionally the human eye has been the source of various weather parameters. For example, the amount of cloud that covers the sky, the type of precipitation, or horizontal visibility, has been based on human observation. Instrument-based Parameters : Numerous instruments have been developed over the years to sense a variety of weather parameters. Some of these instruments directly observe a particular weather parameter at the location of the instrument. The measurement of air temperature by a thermometer is an excellent example of a direct measurement. Other instruments observe data remotely. These instruments either passively sense radiation coming from a location or actively send radiation into an area and interpret the radiation returned to the instrument. Satellite data for visible and infrared imagery are examples of the former while weather radar is an example of the latter. Hybrid Parameters : Hybrid observations refer to weather parameters that are read by a human observer from an instrument. This approach to collecting weather data has been a big part of the weather observing process for many years. Proper sensing of atmospheric data requires proper siting of the sensors.
  • Aerodrome Actual Weather – METAR Decode

    Aerodrome Actual Weather – METAR Decode

    Aerodrome Actual Weather – METAR decode Code element Example Decode Notes 1 Identification METAR — Meteorological Airfield Report, SPECI — selected special (not from UK civil METAR or SPECI METAR METAR aerodromes) Location indicator EGLL London Heathrow Station four-letter indicator 'ten twenty Zulu on the Date/Time 291020Z 29th' AUTO Metars will only be disseminated when an aerodrome is closed or at H24 aerodromes, A fully automated where the accredited met. observer is on duty break overnight. Users are reminded that reports AUTO report with no human of visibility, present weather and cloud from automated systems should be treated with caution intervention due to the limitations of the sensors themselves and the spatial area sampled by the sensors. 2 Wind 'three one zero Wind degrees, fifteen knots, Max only given if >= 10KT greater than the mean. VRB = variable. 00000KT = calm. 31015G27KT direction/speed max twenty seven Wind direction is given in degrees true. knots' 'varying between two Extreme direction 280V350 eight zero and three Variation given in clockwise direction, but only when mean speed is greater than 3 KT. variance five zero degrees' 3 Visibility 'three thousand two Prevailing visibility 3200 0000 = 'less than 50 metres' 9999 = 'ten kilometres or more'. No direction is required. hundred metres' Minimum visibility 'Twelve hundred The minimum visibility is also included alongside the prevailing visibility when the visibility in one (in addition to the 1200SW metres to the south- direction, which is not the prevailing visibility, is less than 1500 metres or less than 50% of the prevailing visibility west' prevailing visibility. A direction is also added as one of the eight points of the compass.
  • NOTICE: This Publication Is Available At

    NOTICE: This Publication Is Available At

    Department of Commerce • National Oceanic & Atmospheric Administration • National Weather Service NATIONAL WEATHER SERVICE INSTRUCTION 10-807 OCTOBER 5, 2017 Operations and Services Aviation Weather Services, NWSPD 10-8 INTERNATIONAL SERVICE AGREEMENTS NOTICE: This publication is available at: http://www.nws.noaa.gov/directives/. OPR: W/AFS24 (M. Graf) Certified by: W/AFS24 (W. Bauman) Type of Issuance: Routine SUMMARY OF REVISIONS: This directive supersedes NWSI 10-807, “International Service Agreements,” dated May 19, 2009. Changes were made to reflect the NWS Headquarters reorganization effective on April 1, 2015. No content changes were made. Signed 9/21/2017 Andrew D. Stern Date Director Analyze, Forecast, and Support Office NWSI 10-807 OCTOBER 5, 2017 International Service Agreements Table of Contents Page 1. Purpose. ..................................................................................................................................... 2 2. Background. ............................................................................................................................... 2 3. Definition of Unique Terms. ................................................................................................................ 3 4. General ............................................................................................................................................ 3 5. Correspondence with Foreign Meteorological Services. ................................................................. 4 6. Services Provided.