The surface weather prognostic charts provide depictions of various surface weather features and significant weather (low-level-flight weather) features out to 48 hours. They are manually produced forecasts, produced with guidance from the LFMII, NGM, and other numerical products. The 12- and 24-hour forecasts (shown in figure 4-3-11) are presented on one chart produced four times a day with both a surface weather prognostic panel and a significant weather features (Sig Wea) panel for each forecast time. The 36- and 48-hour forecasts are on a second chart (shown in figure 4-3-12) produced twice daily, with only a single panel showing combined surface and significant weather features. These charts are frequently used as briefing aids and are displayed in just about every stateside weather office. The following information may be depicted on some or all of these charts. (The charts on which the informa-tion appears are within parentheses after the information. )

Frontal type and position, using the standard symbols presented in figure 4-3-3. (all surface progs)

High and low pressure centers are indicated by Hs and Ls, with the pressure value (underlined) to the nearest whole millibar. (all surface progs)

Pressure center movement is indicated by an arrow for direction, and the forecast speed of movement at the valid time of the chart is entered, in knots, at the head of each arrow. The term STNRY is used to indicate little movement. (24, 48 surface progs)

Isobars may be depicted with a thin solid line and an 8-millibar interval, and labeled in tens and units of millibars. (24, 36, 48 surface progs)

Areas of noncontinuous precipitation (in-termittent precipitation or showers) affecting less than one-half of the area are enclosed by a long-dash- dot line (_____. _____.) surrounding an appropriate weather symbol. Weather symbols used are standard present weather symbols for intermittent/showery precipitation. (all surface progs)

Areas of noncontinuous precipitation affecting one-half or more of the area are surrounded by a long-dash-dot line and are shaded. (all surface progs)

Areas of continuous precipitation are surrounded by a bold solid line (________) and are shaded if one-half or more of the area will be affected (or are not shaded if less than one-half of the area will be affected). (all surface progs)

Areas of liquid and freezing/frozen precipitation are separated by a bold dashed line (_____. _____.) (all surface progs)

Freezing levels are indicated by fine short-dash lines (__ ___  ___ __.) and are labeled with the height, in hundreds of feet. (12, 24 Sig Wea prog)

The surface 32F isotherm is depicted with a dotted line (. . . . . .)and is labeled. (12, 24 Sig Wea prog)

Areas of moderate or greater turbulence from the surface to 24,000 feet are surrounded by a bold long-dash line (_____ _____ _____)

The appropriate turbulence symbol and the height of the base (overlined) and the tops underlined) of the turbulence are written within or near the area. (_______) (12, 24 Sig Wea prog)

Areas of forecast IFR terminal conditions are surrounded by a bold solid line (12, 24 Sig Wea prog)

Areas of forecast MVFR terminal condi-tions are surrounded by a bold scalloped line (12, 24 Sig Wea progs and 36, 48 surface progs)

A forecast discussion about which guidance was used and why it was used is written in plain language with many abbreviations. (34, 48 surface prog)

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