Figure 4-5. Part II: En Route Data Section

METEOROLOGY FLIGHT PLANNING

CHAPTER FOUR

have comments made in the remarks section (Part IV) to elaborate on the warning. The next

set of boxes can be checked to indicate the type and amount of coverage, in addition to providing

the maximum cloud tops of the thunderstorms, when that information is available, along with the

geographic location where the aircrew can expect to encounter the indicated thunderstorm

activity. More than one box may be checked to indicate various possible conditions, so aircrew

should be sure to ask for further details if the explanation given during the brief is unclear.

Finally, observe the typed notice above the location box that reads, "Hail, severe turbulence and

icing, heavy precipitation, lightning and wind shear [can be] expected in and near

thunderstorms." This is yet another reminder of the extremely hazardous nature of

thunderstorms. Even though there is little extra space on the DD 175-1, some experienced

aviators and meteorologist thought that it was very important for aviators to read this message

every time their attention is focused on Block 21 (Figure 4-5).

Figure 4-5 Part II: En Route Data Section

Block 22: Turbulence

The format of the Turbulence Block is similar to that of the Thunderstorm Block, beginning with

a section for advisories, any of which should also have further remarks made in Part IV. Since

turbulence will be experienced in all thunderstorms, this section is only for turbulence not

associated with thunderstorms. Good sources of forecast information include the WS, WA

(Tango), Surface Prognostic Chart, and Low-Level Significant Weather Prognostic Chart.

PIREPs, when available, are also an excellent source of observed information on turbulence.

Blocks 23 and 24: Icing and Precipitation

Much like the sources for turbulence, the icing sources include the WS, WA (Zulu), Surface

Prognostic Chart, and Low-Level Significant Weather Prognostic Chart, and PIREPs. Also, like

FLIGHT WEATHER BRIEFING FORM, DD FORM 175-1 4-9