Page 19 - IFR_Book_Sample-2020

Ch-9 Weather TheoryV8-BAK_Basic Master Frame.qxd 12/19/2019 7:46 PM Page 69

Chapter 9 - IFR Aviation Weather Theory 9-69

WARP Lightning Strike Overlay Narrowband

Radar “Slash”
Symbology

Lightning

Fig. 120A
Courtesy FAA

Fig. 121
Courtesy FAA
Lightning
When using narrowband radar weather depictions, the slashes
(hatched lines) identify areas of weather radar returns greater than
30 dBZ.

Narrowband
Radar “H”
Symbology

Fig. 120B
Courtesy FAA
Center controllers can superimpose lightning strikes
(Figure 120A) over NEXRAD imagery (Figure 120B) on
their screens. It is interesting to note that lightning is
occurring within the Level 3 (heavy precipitation)
returns, reaffirming that thunderstorms are associated
with Level 3 (and higher) returns.

(sometimes called “hatched” lines by controllers). The
slashed lines represent weather radar returns greater than
30 dBZ. That can mean an area of Level 2 returns or
greater. You don’t know how much greater, though. There
could be a Level 3, 4, 5, or 6 storm present in the area. Fig. 122
When the “H” symbol is present, it outlines areas that are Courtesy FAA
greater than 40 dBZ (Figure 122). When using narrowband radar weather depictions, the H’s identi-
If the Center controller advised you that WARP infor- fy areas of weather radar returns greater than 40 dBZ.
mation wasn’t available, you could ask him or her for
information on the slashes and Hs shown by their nar-
rowband weather information. Any area surrounded by an
H is an area to avoid. Center controllers must typically
activate individual buttons to display the slashes, the Hs
and the slashes and Hs together (the WX#1 key, the
WX#2 key, or the WX#3 key, respectively) as shown in Fig. 123
Figure 123. If both slashes and Hs are being displayed,
then avoid the Hs and use caution for the slashes since the The Center controller can selectively isolate the slashes and Hs or
border between them and the Hs indicate a Level 2 return. allow them both to identify weather on their radar screen.
In this instance, the best way to let the controller know
you’re interested in slashes and Hs, is to say something activate your Weather #3 key and tell me the positions of
like, “Sir (or ma’am, and don’t get these mixed up or the slashes and Hs’s relative to my airplane and its direc-
you’ll end up in a holding pattern somewhere), will you tion of flight?”