Drift Near Frontal Thunderstorms; Estimating Distances From Strike Dots - INSIGHT STRIKE FINDER Pilot's Manual

STRIKE FINDER
In the example shown in Figure 23-B, a 50 kt cross wind drifting the
plane toward the storm, has decreased the avoidance distance or angle from
30-degrees to 16-degrees. The pilot should compensate for drift with
additional crabbing (turning into the wind). The degree of crabbing will vary
based on several factors, (see Table 1 (p.23) and Table 2 (p.29), also Effect
of Wind Drift section, for further details).
50 kt Cross Wind
44˚
Figure 23-A
Cross Wind Effect On Avoidance Angle

Drift Near Frontal Thunderstorms

Flying toward frontal activity poses special problems. Unlike air mass
weather where similar wind conditions may exist for hundreds of miles,
frontal conditions almost always include a significant wind shift.
The variable nature of fronts and the wide range of conditions
encountered there dictate careful pre-flight planning and cautious
in-flight procedures.
Numerous, powerful storms associated with fronts, may make wind
conditions unpredictable. A line of frontal storms (squall-line) may be
impassible; give them a wide berth.

Estimating Distances From Strike Dots

Figure 24-A (p.31) shows the display at 200 nm range view. Using this
knowledge and the One-Quarter Rule, the strike dot at half range can be
calculated to be approximately 50 nm from the projected track. No deviation
is required. Figure 24-B (p.31) shows the display at 50 nm range view.
dots
plotted at the same place, are approximately 12.5 nm from the
projected track. A deviation of 30 to 90-degrees (dependent on wind drift),
is required.
30
Track
DIGITAL WEATHER AVOIDANCE
16˚
Figure 23-B
PILOT'S
50 kt Cross Wind
Strike
GUIDE