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Ch-10 IFR Weather Charts-V8-NEW-NewUpdate_Basic Master Frame.qxd 12/19/2019 4:37 PM Page 46

10-46 Rod Machado’s Instrument Pilot’s Handbook
two you are most likely to have to deal
with (even moderate turbulence is cer-
tainly no fun). A light aircraft is one
that weighs less than 15,500 pounds. I
think that means you, unless you’re A
bringing your flight bag with you again.
You definitely want to avoid severe
(SEV) turbulence to say nothing about
extreme (E) turbulence. AIRMET
Tango is displayed for turbulence only.
It does not include AIRMET Tango for
surface winds or low-level wind shear.
Turbulence, convective, tropical
cyclone, and international thunder-
storm SIGMETs are also overlaid. You
can select flight levels in 3,000 feet
increments when looking at forecast
turbulence.
The Icing Forecast Button
The forecast icing panel (Figure 66, B C
position A) offers a three-dimensional, Fig. 65
color-coded icing severity depiction for
various altitudes. Yippie! Finally, anoth-
er valuable and useful means of por-
traying the potential for ice during The GFA Turbulence panel calculates turbulence in terms of the EDR or Eddy
flight (as a VFR pilot you’ll be con- Dissipation Rate. What matters here is that you can convert the EDR color codes (posi-
cerned about freezing rain, but not in- tion B) into the traditional values for evaluating forecast turbulence based on the weight
of your aircraft (heavy, medium and light ) as shown by the scaled in position B.
flight icing, as you won’t be flying in the
clouds). The icing severity
diagnoses areas of expected
trace, light, moderate, and
heavy icing (position B) at
3,000-foot intervals up to
FL300 (position C). Two- A
dimensional AIRMET Zulu
and Icing, convective, tropical
cyclone and international
thunderstorm SIGMET poly- D
gons are overlaid on the
graphic valid at the selected
level (position D). You may
also choose "MAX" to display
the maximum icing severity
for a location regardless of C
altitude and all AIRMET
Zulu and SIGMET polygons.
When "SFC" is selected (posi-
tion E), the FIP is replaced by E
a grid showing winter precip-
itation type and likelihood.
Weather symbols denoting
the winter precipitation type B
and intensity are overlaid on Fig. 66
the graphic along with the
NWS winter storm, blizzard,
freezing rain, lake effect
snow, winter weather, and
The GFA icing panel is a wonderful tool for providing you with a macro view of the icing potential
freezing fog polygons.
for your chosen route on a cross country trip.