Weather Maps

1. Weather Maps

3. Much information is needed to interpret what is happening with the atmosphere. Need to condense this information in a small space Need to show the geographic characteristics of this data Weather maps can both display this data and summarize the patterns

4. Station Model Allows the data to be plotted in a condensed and usable format

5. Location of the station on the map. The name of the location or airport abbreviation might be given nearby.

6. Temp Temperature information in degrees Fahrenheit.

7. Temp dewpt Dew Point Temperature in degrees Fahrenheit.

8. Temp dewpt Wind direction A staff is rotated around the station. Remember, winds are identified as the direction FROM which they come. This would be a west northwest wind or about 290º.

9. Temp dewpt Wind Speed Attached to the staff are symbols for speed.

10. note, it is not on the end of the wind direction staff The coding for the wind speed symbols can be generalized as: half staff about 5 knots full staff about 10 knots these are additive for the total amounts three full staffs=30 knots flag about 50 knots 65 knots

11. pressure Temp dewpt Current Barometric Pressure

12. Barometric Pressure is VERY important! average barometric pressure at sea level is 1013.25 mb. current barometric pressure is reported to the nearest TENTH BUT, they don’t want to waste space

13. average barometric pressure at sea level is 1013.25 mb. barometric pressure varies around this value + about 30 = 1043 somewhat higher 1013.3 somewhat lower - about 30 = 983

14. 133 x average barometric pressure at sea level is 1013.25 mb. barometric pressure varies around this value they do not PRINT the beginning number or numbers 1013.3 ---- 13.3 they, also, do not PRINT the decimal point, but report to the nearest TENTH

15. From the three numbers, you must INTERPRET whether the preceding value is 10 or 9 Which would make the value most realistic?

16. add the decimal point and then consider which, a 10 or a 9 places the value NEAREST to the average pressure of 1013.25 mb.

17. (1013.3) What is the pressure? 084 08.4 1008.4 962 96.2 996.2 281 28.1 1028.1 987.5 875 87.5 322 32.2 1032.2

18. Not only is the pressure itself important, but so is the way the pressure has been changing. So, more information may be given and must be coded.

19. pressure Temp trend dewpt How has the barometer been changing? + it is higher now than in the past - it is lower now than in the past

20. pressure Temp change trend dewpt How much the pressure has changed the amount of change in the past three hours again, reported in TENTHS without the decimal

21. pressure Temp change shown trend dewpt What has the pressure been doing? Shown diagrammatically

22. pressure Temp change shown trend dewpt Total amount of cloud graphic depiction of percentage of the sky covered by clouds

23. about 60% no clouds about 10% about 75% about 25% about 80% completely overcast about 40% sky obscured about 50%

24. highclouds middleclouds pressure Temp change shown trend lowclouds dewpt Symbol positions to identify the cloud types Cloud types tell much about the weather conditions. The cloud types are identified by symbols, and classed as low, middle, and high clouds.

25. highclouds middleclouds pressure Temp change shown trend lowclouds dewpt How much of the sky is covered by low and middle cloud cover? low or middle cloud cover What amount, in tenths, of the sky is covered by low or middle clouds. This is a coded number with the percentage close to the printed number.

26. highclouds middleclouds pressure Temp change shown wxnow trend lowclouds dewpt What is the present weather? low or middle cloud cover The current weather is very important. A detailed set of symbols provides weather descriptions.

27. Samples of present weather symbols. rain fog * snow haze slight rain showers , thunderstorm drizzle . ice or snow pellets lightning cloud development not observed

28. Combining symbols tells more of the detail. intermittent rain, slight at time of observation continuous rain, slight at time of observation continuous rain, moderate at time of observation intermittent rain, moderate at time of observation intermittent rain, heavy at time of observation continuous rain, heavy at time of observation

29. 100 different symbols provide details about the PRESENT WEATHER.

30. highclouds middleclouds pressure Temp change shown visibility wxnow trend lowclouds dewpt The visibility is especially important for pilots. low or middle cloud cover Visibility is given in miles and fractions

31. highclouds middleclouds pressure Temp change shown visibility wxnow trend lowclouds low or middle cloud cover dewpt PAST The past weather uses symbols. , *

32. highclouds middleclouds pressure Temp change shown visibility wxnow trend lowclouds low or middle cloud cover dewpt PAST when Time precipitation began or ended Coded for how many hours ago the precipitation began or ended. Again, the code is close to the number of hours.

33. highclouds middleclouds pressure Temp change shown visibility wxnow trend lowclouds low or middle cloud cover dewpt PAST when base Height of cloud base Coded height of base of clouds. Important for pilots.

34. highclouds middleclouds pressure Temp change shown visibility wxnow trend lowclouds low or middle cloud cover dewpt PAST when base The amount of precipitation amount Amount of precipitation is plotted in inches to the nearest hundredth of an inch.

35. Decode this station. 237 ,, 75 - 1 12 65 6 3 4 36

36. yes any low clouds?any middle clouds?any high clouds?amount of low and middle cloudsheight of cloud basevisibilitybarometric pressuretrend in pressurepressure three hours agohow has pressure changedpresent weatherpast weatherwhen precipitation began/endedamount of precipitation yes 237 ,, 75 yes - 1 12 6 4 65 6 3 1 mile 4 36 1023.7 mb falling 1024.9 down then steady temperaturedew pointwind directionwind speedamount of sky cover 75 continuous slight drizzle 65 rain south 4 25 knots .36” 80%