1 / 30

Lab 2: METAR Decoding and Station Observations

Lab 2: METAR Decoding and Station Observations. Weather Forecasting Handbook Ch . 3. Station Plot Format. PPP = sea-level pressure pp = pressure tendency over the past 3 hours a = overall pressure tendency RR = precipitation TdTd = dewpoint temperature VV = visibility in miles

gabi
Download Presentation

Lab 2: METAR Decoding and Station Observations

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lab 2: METAR Decoding and Station Observations Weather Forecasting Handbook Ch. 3

  2. Station Plot Format • PPP = sea-level pressure • pp = pressure tendency over the past 3 hours • a = overall pressure tendency • RR = precipitation • TdTd = dewpoint temperature • VV = visibility in miles • ww = current weather • TT = temperature • dd = wind direction • ff = wind speed • N = cloud cover

  3. Station Plot – Temperature and Dewpoint Temperature • The temperature (measured in degrees Fahrenheit) is at the upper left side of the station’s circle. • Dewpointtemperature (measured in degrees Fahrenheit) is on the bottom left side of the station. • Temperature is 27°F and the dewpoint temperature is 25°F.

  4. Station Plot – Current Weather • Located directly below the temperature • Weather symbol is not included in the station plot if nothing interesting is happening. • Here, there is light rain

  5. Station Plot – Precipitation • Precipitation during the past 24 hours is given on the bottom right side. • This is measured in inches • Here, it has rained 0.31 inches over the past 24 hours

  6. Common Weather Symbols:

  7. Station Plot – Cloud Cover • Cloud cover is indicated by the amount of shading in the station’s circle • no shading = clear • ¼th shaded = few clouds • half shaded = scattered clouds • ¾th shaded = broken clouds • fully shaded = overcast conditions

  8. Station Plot – Wind Speed and Direction • Wind barb indicates wind direction and speed • The barb points in the direction FROM where the wind is blowing. • Wind speed is measured (in knots) by the number and type of flags on the barb. • Short flag=5kts, Long flag=10kts, Triangle=50kts • Here, we have a northwesterly wind at 30 kts http://www.meteor.wisc.edu/~hopkins/aos100/wndcod2.gif

  9. Station Plot – Sea Level Pressure • Sea level pressure is on the top right side • Need to add a 9 or a 10 in front of numbers on map and a decimal goes between the last two numbers • Typical values between 970mb and 1030mb • Here, the SLP is 999.7 mb

  10. Station Plot – Pressure Tendency • The pressure tendency is given to the right of the cloud cover symbol • The pressure tendency is given over the past 3 hours and the units are tenths of millibars • The pressure tendency trend provides a graphic illustration of how the change of pressure has occurred. • Here, the pressure has decreased 1.1 millibars continuously over the past 3 hours

  11. Station Plot – Pressure Tendency Trend

  12. Examples http://cimss.ssec.wisc.edu/wxwise/station/page5.html

  13. METAR • METAR is a format for reporting weather information. • Raw METAR is the most popular format in the world for the transmission of weather data. • This METAR example is from Trenton-Mercer Airport near Trenton, New Jersey, and was taken on 5 December 2003 at 18:53 UTC. METAR KTTN 051853Z 04011KT 1/2SM VCTS SN FZFG BKN003 OVC010 M02/M02 A3006 RMK AO2 TSB40 SLP176 P0002 T10171017=

  14. METAR – Type and Station ID TYPE ID TIME WIND VIS WX SKY T/TD ALT REMARK METARKORD041656Z19020G26KT6SM-SHRABKN07012/08A3016RMK AO2 • Type - METAR • METAR is the scheduled observation taken at the end of each hour. • SPECI is an observation taken at an unscheduled time due to certain criteria that is met such as low visibility, low clouds, frozen precipitation, or thunderstorms. • Station ID - KORD • In this example, K refers to a North American Station and ORD is the three letter ID for O’Hare. • Other example: KDEN (Denver, CO)

  15. METAR – Time & Date TYPE ID TIME WIND VIS WX SKY T/TD ALT REMARK METARKORD041656Z19020G26KT6SM-SHRABKN07012/08A3016RMK AO2 • Time and Date – 041656Z • The 04 represents the day of the month • The 1656 represents the time at which the observation went out • The Z represents that the time is in ZULU or UTC (Universal Time Code).

  16. METAR - Winds TYPE ID TIME WIND VIS WX SKY T/TD ALT REMARK METARKORD041656Z19020G26KT6SM-SHRABKN07012/08A3016RMK AO2 • Winds – 19020G26KT • The 190 (the first three numbers) is the direction of the winds in degrees from 0 to 360 degrees. • The 20 (next two numbers) is the speed of the winds in knots. • The G26 represents the wind gusts of 26 knots. • The KT simply means knots. It will always be at the end

  17. METAR - Visibility TYPE ID TIME WIND VIS WX SKY T/TD ALT REMARK METARKORD041656Z19020G26KT6SM-SHRABKN07012/08A3016RMK AO2 • Visibility – 6SM • The 6SM simply means 6 statute miles. • Occasionally you might see visibility up to 20 or 30 SM but for the most part it will go from < ¼ (visibility below ¼ SM) up to 10 SM.

  18. METAR – Present Weather and Obscurations TYPE ID TIME WIND VIS WX SKY T/TD ALT REMARK METARKORD041656Z19020G26KT6SM-SHRABKN07012/08A3016RMK AO2 • Present weather and obscurations –SHRA • (-) is the designator for light. Precipitation will be light (-), moderate (), or heavy (+) based on certain criteria must be met. • SH means showers and RA means rain. • The following is from the FMW-1 Handbook

  19. METAR – Cloud Cover TYPE ID TIME WIND VIS WX SKY T/TD ALT REMARK METARKORD041656Z19020G26KT6SM-SHRABKN07012/08A3016RMK AO2 • Sky Condition – BKN070 • BKN represents a broken sky. (The clouds cover 5/8 to 7/8 of the sky) • The 070 represents the clouds are at 7,000 feet (simply add 2 zeros to get the height) • The cloud cover will be either be FEW (1/8 to 2/8 cloud coverage), SCT (SCATTERED, 3/8 to 4/8 cloud coverage), BKN (5/8-7/8 coverage), and OVC (OVERCAST, 8/8 Coverage). • There will often be more than 1 designator (i.e. SCT035 BKN090 OVC140) • An indefinite ceiling caused by fog, rain, snow, etc., will require a designator as VV (Vertical Visibility). VV is how high you can see vertically into the indefinite ceiling. • Significant clouds such as TCU (towering cumulus), CB (cumulonimbus), or ACC (altocumulus castellanus) will be found on the end of a category (i.e. SCT035TCU)

  20. METAR – Temperature, Dewpoint, Altimeter/Pressure TYPE ID TIME WIND VIS WX SKY T/TD ALT REMARK METARKORD041656Z19020G26KT6SM-SHRABKN07012/08A3016RMK AO2 • Temperature and Dewpoint – 12/08 • 12 represents the temperature in Celsius • 08 represents the dewpoint in Celsius • If the temperature or dewpoint falls below 0, then there will be an “M” before it (i.e. 03/M02). “M” means minus • Altimeter/Pressure – 3016 • A simply stands for Altimeter • 3016 means 30.16 inches of mercury for the pressure

  21. METAR – Remarks TYPE ID TIME WIND VIS WX SKY T/TD ALT REMARK METARKORD041656Z19020G26KT6SM-SHRABKN07012/08A3016RMK AO2 • Remarks – RMK A02 • RMK simply mean remarks and marks the end of the standard METAR observation and the beginning of the remarks that are put in as necessary. • A02 means that the site is automated and has a precipitation sensor. If it were A01, there would be no precip sensor. • There are many remarks and the FMH-1 gives a full listing

  22. Remarks • Lightning: frequency, type, and direction of lightning • occasional, OCNL; frequent, FRQ; or continuous, CONS; cloud-to-ground, CG; in-cloud, IC; cloud-to-cloud, CC; cloud-to-air, CA • e.g., OCNL LTGICCG NW for occasional lightning in-cloud and cloud-to-ground northwest

  23. Remarks • Beginning and ending times of weather phenomena: expressed in minutes past the hour • e.g., TSB05E40 for thunderstorm began 5 minutes past the hour and ended 40 minutes past the hour • Sea-level pressure: station pressure (mb) reduced to sea level • e.g. SLP122 for sea-level pressure of 1012.2 mb

  24. Remarks • Hourly precipitation:preceded by P and expressed in hundredths of an inch • e.g. P0022 = 0.22 inches of precipitation • 3- and 6-hour precipitation: preceded by 6 and expressed in hundredths of an inch • e.g. 60061 = 0.61 inches of precipitation in the last 6 hours • 24-hour precipitation: preceded by 7 and expressed in hundredths of an inch • e.g. 70063 = 0.63 inches of precipitation in the last 24 hours

  25. Remarks • Hourly temperature and dew point: preceded by T and followed with 0 if the temperature is 0°C or higher, or 1 if the temperature is less than 0°C and followed by the temperature in tenths of a °C, then 0 or 1 again followed by the dew point in tenths of a °C. • e.g. T00940079 = temperature of 9.4°C and dew point of 7.9°C • 6-hour maximum temperature: preceded by 1 and followed by 0 or 1 to denote temperatures above or below 0°C, respectively, and expressed in tenths of a degree • e.g. 10167 = maximum temperature of 16.7°C • 6-hour minimum temperature: preceded by 2 and followed by 0 or 1 to denote temperatures above or below 0°C, respectively, and expressed in tenths of a degree • e.g. 20094 = minimum temperature of 9.4°C

  26. Remarks • 3-hour pressure tendency: preceded by 5 and followed by 0 though 9 to indicate trend, followed by the amount in tenths of millibars • e.g. 51007 Interpretation: increased then steady with a change of 0.7 mb

  27. Examples 1. KMLU 171153Z AUTO 03007KT 6SM RA BR BKN009 BKN014 OVC025 09/08 A3001 RMK AO2 SLP163 P0013 60033 70033 T00940079 10167 20094 51007 TSNO= • Location: KMLU (Monroe) • Day of month: 17, Time: 11:53 UTC • Report is fully automated, with no human intervention or oversight • Wind: True direction = 30°, Speed: 7 knots • Visibility: 6 Statute Miles • Weather: Rain and Mist • Clouds: broken at 900 ft, broken at 1400 ft, and overcast at 2500 ft • Temperature: 9°C • Dewpoint: 8°C • Altimeter: 30.01 in Hg

  28. Examples 1. KMLU 171153Z AUTO 03007KT 6SM RA BR BKN009 BKN014 OVC025 09/08 A3001 RMK AO2 SLP163 P0013 60033 70033 T00940079 10167 20094 51007 TSNO= • SLP163 = Sea level pressure of 1016.3 mb • P0013 = 0.13 inches of rain in the last hour • 60033 = 0.33 inches of rain in the last 3 hours • 70033 = 0.33 inches of rain in the last 24 hours • T009440079 = Temperature of 9.4°C and dew point of 7.9°C • 10167 = Maximum temperature of 16.7°C • 20094 = Minimum temperature of 9.4°C • 51007 = Increased then steady with a change of 0.7 mb • TSNO = lightning information not available

  29. Examples 2. KINL 181155Z 04006KT 10SM CLR M18/M22 A3012 RMK AO2 SLP234 T11831222 11122 21189 53012 • Location: KINL (International Falls, MN) • Day of month: 18, Time: 11:55 UTC • Wind: True direction = 40°, Speed: 6 knots • Visibility: 10 Statute Miles • Weather: Clear • Temperature: -18°C • Dewpoint: -22°C • Altimeter: 30.12 in Hg

  30. Examples 2. KINL 181155Z 04006KT 10SM CLR M18/M22 A3012 RMK AO2 SLP234 T11831222 11122 21189 53012 • SLP234 = Sea level pressure of 1023.4 mb • T11831222 = Temperature of -18.3°C and dew point of -22.2°C • 11122 = Maximum temperature of -12.2°C • 21189 = Minimum temperature of -18.9°C • 53012 = Decreased then increasing with a change of 1.2 mb

More Related