1. Surface 850 mb 700 mb 500 mb 300 mb NEMOC Training Department Chart Format

2. Chart Basics zIsobars - Lines of equal pressure. Drawn on constant height charts as solid black lines. zContours - Lines of equal height. Drawn on constant pressure charts as solid black lines. zIsotherms - Lines of equal air temperature. Drawn as dashed red lines every 5 o C. Base 0 o C. Note - 0 o C on 850 mb chart is dashed blue. L

3. Chart Basics (cont.) zTrough Axes - An elongated area of relatively low pressure on a constant height chart or low height on a constant pressure chart. Depicted as dashed brown lines on the surface and solid black lines aloft. zRidge Axes - An elongated area of relatively high pressure on a constant height chart or high height on a constant pressure chart. Depicted as zig-zag black lines.

4. Chart Basics (cont.) zMoisture - Areas where dew point depression is close to saturation are considered “moist”. Encompassed by green scalloping. yAreas with plotted dew point depressions of 3, 4, or 5 are scalloped in green and the edge is shaded green. yAreas with plotted dew point depressions of 0, 1, or 2 are scalloped in green and shaded solid green, using a darker shade of green than above.

5. Jet Stream Chart Basics zIsotachs - Lines of equal wind speed. Drawn as dashed green lines. yDrawn using 20 knot increments. Base of 50 knots. zJet Max - A concentrated area of strong winds at upper levels. Center is shaded purple. yMore of less football/banana shaped. yLabeled with the highest wind speed believed to be present in the max. xLabeled speed must at least equal the highest wind reported and may not exceed the max reported wind by more than 10 knots. J115

6. Jet Stream Chart Basics (Cont.) zJet Stream Axis - Band of maximum winds at upper levels. Drawn as solid purple line. J115

7. Intervals zConstant Height Chart - Isobars drawn using... ySurface - 4 mb increments. Base of 1000 mb. zConstant Pressure Charts - Contours drawn using... y850 mb - 3 dam increments. Base of 150 dam. y700 mb - 3 dam increments. Base of 300 dam. y500 mb - 6 dam increments. Base of 558 dam. y300 mb - 12 dam increments. Base of 912 dam. y250 mb - 12 dam increments. Base of 912 dam. yNote: 1 decameter (dam) = 10 meters

8. Review zThe 700 mb Chart is normally labeled every _____ meters. y30 zIsotachs are drawn at what intervals? y20 knots zWhat color is past history on a surface chart? yYellow zWhat is the interval and color of isotherms on upper air charts? y5 o C - Red