1. Part I Maps and Numbers

2.  Station Models  Isoline Maps

3. Station model: an abbreviated plot of weather station data

4. Station model: abbreviation of weather station data

7. Station model: Text, pp. 488-489, textbook Cloud cover Wind direction Wind speed Pressure (without decimal point; without initial 10 or 9)(mb) Air Temperature Dew point Present weather pressure change in past 3 hrs (without decimal pt)

8. Cloud cover  Circle centered on station location scattered overcast

9. Air temp; dew point temp Air temp Dew pt temp

10. Wind direction Direction arrow points is wind direction (direction wind is coming FROM) If calm, no arrow and double circle

11. Wind speed

12. “knot” Nautical mile per hour 1 knot = 1.15 mph; 1.9 km/hr

13. Present weather

14. Current pressure 162 3 numbers; in mb; no decimal point; 10 or 9 at beginning of number is NOT shown 162 = 1016.2 mb Does number begin with “10” or “9” ?

15.  353 ?  1035.3 mb  175?  1017.5 mb  985?  998.5 mb  893?  989.3 mb  074?  1007.4 mb  890?  989 mb

16. Pressure tendency during past three hours 02 Amount of change; mb; No decimal shown;

17. 07 13

18. Last night

19. Station Model Exercise :  In pairs:  Pick any 4 cities and make station models.  Each pair make 4

20. Isoline maps Interpolate between discrete data points to create a continuous “surface”:  Helps us to visualize the data examples:  Elevation surface  Pressure surface  Temperature surface

21. Topographic map an elevation surface Contour lines

22. Temperature map 60 50 40 30 20 isotherms

23. Pressure surface isobars

24. Isolines “connect points of equal value” Types of isolines:  Isobars: pressure  Isotherms: temperature  Isohyets: precipitation amount  Isodrosotherms: dew point  Isogons: wind direction  Isotachs: wind speed  Isoshears : wind shear

25.  All data values on an isoline are equal.  The interval between lines is constant for the entire map. 45 39 43 52 64 69 58 70 40 50 60

26. Rules for making an isoline map: Lower values are always on one side of isoline ; higher values on the other side. Isolines NEVER CROSS OR TOUCH, NEVER SPLIT. Isolines will generally be SMOOTH AND PARALLEL. LABEL each isoline on the ends for open and in the center for closed isolines. Interpolate between points as exactly as possible! Do NOT draw lines where there are no data points. Use a pencil 35

27. 48 32 35 52 42 40 60 65 66 38 45 71 78 74 69 40 39 50 51 52 5152 62 64 59 63 62 75 62 65 39 50 72

28.  Trough: line of relatively low values  (Isolines point to higher values)  Ridge: line of relatively high values  (Isolines point toward lower values) Terms usually used on pressure maps

32.  Gradient  Steep/strong gradient: close isolines  Weak gradient: widely spaced isolines

33. 1020 1018 1016 10141012 1010 1008 1006 1004 500 miles

35. Exercise Create an isobar map from Station Models (station model map of US Plains states)  Use a 5 mb interval, starting at 1000. Identify the pressure on each station model. Remember to:  A) insert the decimal to give the number a tenths place  B) add a 9 if the first number is greater than 5 or a 10 if the first number is less than 5. examples: 184 = 1018.4 mb; 997 = 999.7 mb