Thunderbolt 350BL series User manual

11
INSTRUCTION
MANUAL
INSTRUCTION
MANUAL
MODEL 350BL SERIES

ENTER
LCD TEXT
SCREEN
POWER
ON/OFF
WARNING &
POWER /ON LEDs
SPEAKER
Displays the unit’s Menu informa-
tion and current storm information
during operation.
Used to select items from the Menu
and enter values from the unit’s
Menu. Also used to immediately
move from the Menu to normal scan-
ning operation.
Speaker for the Audible Alarm.
There are two LED lights - green and
red. The green light flashes when the
unit is activated, and continuously
blinks during normal scanning opera-
tion. The red LED is activated when
a storm has approached within the
user-determined warning range.
MODEL 350BL SERIES

CONTROLS & FEATURES
The SCROLL UP or SCROLL DOWN
buttons permit user to move
through the unit’s Menu, as well as
access the Menu when the unit is in
normal scanning operation.
Button allows user to turn the
Audible Alarm on or off.
9V D/C
A/C Adapter jack
for optional
A/C power operation.
BATTERY COMPARTMENT DOOR
Compartment door for 9V battery.
SCROLL UP
TONE ON/OFF
SCROLL DOWN
MODEL 350BL SERIES

4
THUNDERBOLT® CONTROLS & FEATURES .............2
PRODUCT OVERVIEW .................................................5
INSTALLATION AND SETUP .......................................6
Operating Positions ...............................................6
Power Sources for ThunderBolt ............................6
Batteries ...........................................................6
External AC Adapter .........................................7
Unit Power On/Off .................................................7
LCD Display Overview ...........................................8
Accessing and Using the Main Menu ....................8
Main Menu User Selections ...................................8
STORM DETECT ..............................................9
ALARM RANGE ..............................................9
ALARM MODE ..............................................10
SENSITIVITY ..................................................10
NOISE TEST ...................................................11
BACKLIGHT ON/OFF .....................................12
Audible Alarm Tone Operation ............................13
Backlight Operation ..............................................13
BASIC UNIT OPERATION ...........................................15
Storm Detection ...................................................15
Text Messages .....................................................18
Points to Remember ............................................21
Anatomy of a Thunderstorm ...............................22
Types of Lightning ...............................................24
Common Questions about Operation ..................26
PRODUCT SUPPORT ...................................................28
Care and Maintenance .........................................28
Customer Service and Support ............................28
One-Year Limited Warranty ................................29
Service Policy .......................................................30
ThunderBolt Storm Detector Accessories................30
RECOMMENDED SETTINGS ......................................31
This Instruction Manual applies to the ThunderBolt
®
Utility (TB-U1),
ThunderBolt
®
Personal (TB-CB1/CG2/CR1/CA1), ThunderBolt
®
Desk
(TB-CGS/CAS), ThunderBolt
®
Storm Chaser (TB-SC1).
TABLE OF CONTENTS

5
PRODUCT OVERVIEW
The ThunderBolt
®
Storm Detector is a personal, hand-held weather monitor.
The ThunderBolt utilizes self--contained, copyrighted, proprietary software
and electronic technology to detect and track the motion of thunderstorms. It
analyzes lightning activity within storm cells and supercells*, and is capable
of identifying the presence of squall lines**, which can occur in conjunction
with thunderstorm activity.
IMPORTANT! ThunderBolt uses the latest electronic and computer
technology to detect and track thunderstorms. However, thunderstorms
can be a rapidly changing weather phenomenon, and the information
provided by the ThunderBolt should, whenever available, be used in con-
junction with other weather information sources. Remember that the
ThunderBolt detects ACTIVE storms, and cannot predict when or
where a particular storm may form, and/or where the first lightning
stroke occurs. Because of the variable factors associated with lightning
due to amperage of the stroke, polarity and orientation to the ground,
ThunderBolt does not detect and track individual lightning strokes, but ana-
lyzes data from entire storm cells as they move.
Storms are detected and analyzed within 75 miles of user location. Measured
from the point of user location, ThunderBolt’s advanced proprietary technol-
ogy converts data from the intensity of electro-magnetic field emissions of
lightning activity within a storm cell into digital signals. The signals are
then fed into a microprocessor for analysis. The UNIT tracks and alerts the
user through text messages on its Liquid Crystal Display (LCD) screen, red
and green Light Emitting Diode (LED) indicators and through audible tone
warnings. See page 15 of this manual for a list of text messages and their
meanings.
** Supercells are severe thunderstorms typically larger and more violent than normal storms and often
** result in the formation of tornadoes. They comprise approximately 10% of all thunderstorms.
** Squall lines occur when converging air currents create cumulonimbus cloud activity forming groups
** of storms and resulting in heavy precipitation.
** Both Super-cells and Squall Lines are capable of producing high winds, severe rain and tornadoes.

6
INSTALLATION AND SETUP
OPERATING POSITIONS
The ThunderBolt
®
Storm Detector can be carried indi-
vidually or installed on a stationary mount. The unit is
completely operable while in its carrying pouch with easy
access to all controls.
Mounting the ThunderBolt allows it to be installed verti-
cally on a flat surface, such as a desk or wall, allowing the
unit to be easily removed for mobile operation.
The ThunderBolt unit will not operate properly if oriented
on its side. The unit is designed to operate either vertically
(hand-held or using the wall mount or the desk stand), or
lying flat on a horizontal surface.
POWER SOURCES FOR THE THUNDERBOLT
1. BATTERIES
The ThunderBolt operates on one standard 9V battery. The battery com-
partment is located on the back of the lower half of the unit between
the EX, SPK and 9V DC jacks. To open the Battery
Compartment Door, use the heel of your palm, or thumbs,
to press door downward and away from unit. NOTE: The
Battery Compartment Door has been designed to provide
a secure fit to withstand rugged use, and may initially be
stiff and difficult to open, but will become easy to slide
open with regular use. Once opened, clip the connec-
tor over the battery terminals and securely close battery
compartment door.
Battery life is constantly monitored by the UNIT’S computer. A LOW
BATTERY warning message is periodically displayed once remaining
battery life drops below 5-7 hours. Always replace battery as soon as pos-
sible when warning message is displayed. The battery should be removed
if the ThunderBolt is to be stored for an indefinite period of time to avoid
accidental leakage and corrosion of terminals.

7
2. EXTERNAL AC ADAPTER
A ThunderBolt International-approved low-noise external
adapter may be used to power the ThunderBolt
®
Storm
Detector. The adapter jack is labeled 9V DC and is located on
the back of the unit above the battery compartment door. A
115 Volt-AC and 220 Volt-AC Adapter are available from
ThunderBolt International, Inc.
NOTE: The use of a surge protector is highly recommended with the AC
Adapter to minimize incidences of “false triggering”* which often occur
due to spikes in voltage current, as well as a possible “freeze” of informa-
tion from the unit (requiring a re-start of the unit). It is recommended when
first using the AC Adapter to run a unit NOISE TEST (see page 10), while
on AC, as well as a periodic NOISE TEST thereafter if the unit is running
on AC continuously.
IMPORTANT! Use of a non-specified adapter will cause inaccurate or
improper operation of the unit and will damage the power supply circuitry.
Use of a non-specified adapter will void the ThunderBolt Warranty.
UNIT POWER ON/OFF
To turn on the unit, press the POWER ON/OFF button on the front of the
unit (see page 1). The unit has been properly activated when the LED
light at the tip of the unit flashes. Release your finger from the ON/OFF
button after the LED light has flashed. Within a few seconds after the unit
powers on, the ThunderBolt model number will appear on the screen,
replaced by TONE IS NOW ON, and then the Main Menu will appear on
the LCD display and the green LED light will begin to continuously blink
to indicate normal operation.
To turn off the unit, press the POWER ON/OFF button and hold until alarm
sound is emitted, and then release the ON/OFF button at any time. This
delayed deactivation prevents the unit from being turned off inadvertently
by alerting the user.
NOTE: To conserve the life of the batteries, the unit is programmed automatically to turn off after
approximately five hours if no buttons are activated. The auto shut-off feature is disabled if the
external AC adapter is powering the unit.
* False triggering is when the unit indicates false storm activity because of changes of power
voltage or nearby noise interference (see page 10).

8
LCD DISPLAY OVERVIEW
The LCD Display, between the LED Light Display and the Unit Controls,
provides the user the Menu Options and Text Messages during operation.
Only two lines of text can be viewed at a time. NOTE: Menu use follows
this section of the manual. Text Messages and definitions are discussed on
page 18.
ACCESSING AND USING THE MAIN MENU
The Main Menu appears on the LCD Display when the Unit
is activated. Use the SCROLL UP/DOWN (see page 2) but-
tons to move through the user-selectable choices on the Main
Menu. To select an item from the Menu, move the blinking cur-
sor to the desired item number and then press the ENTER button (see
page 1). Once initial UNIT programming has been completed, the
ThunderBolt
®
automatically begins a normal storm detection routine
(SCANNING mode) if no other button is pressed within approximately
7 seconds. You may return to the Menu at anytime. Simply press and
release either of the SCROLL UP/DOWN buttons to call back the Main
Menu.
MAIN MENU USER SELECTIONS
There are five user-selectable choices contained in the Main Menu. These
will appear on the screen two at a time, according to the list below:
1. STORM DETECT
2. ALARM RANGE
3. ALARM MODE
4. SENSITIVITY
5. NOISE TEST
6. BACKLIGHT ON/OFF
The ALARM RANGE, ALARM MODE, and SENSITIVITY should be set
when initially using the unit, and altered whenever a change of situation
dictates. The NOISE TEST SHOULD BE RUN INITIALLY, and whenever
a change of environment occurs.

9
1. STORM DETECT
Once the ThunderBolt
®
is powered on and the Main Menu accessed,
the unit will automatically return to normal storm detection (or
SCANNING) mode if no other menu selection is made within approxi-
mately 7 seconds. You may also manually return to normal storm
detection by selecting STORM DETECT mode and then press-
ing the ENTER button, immediately putting the unit into normal
storm detection. Once the unit is SCANNING, the cursor will move
back and forth, and the selected SENSITIVITY (normal or high) will be
displayed.
2. ALARM RANGE
ALARM RANGE allows the user to determine, based on need and/or
application, what distance ThunderBolt will begin providing approach-
ing storm warning on its VISUAL ALARM (red LED) and AUDIBLE
ALARM (Tone). See page 26 for recommended settings. Selecting this
option allows the user to choose the warning
range (distance in miles from user location)
for activation of the VISUAL ALARM and the
AUDIBLE ALARM. Once ALARM RANGE has been selected, the VISUAL
ALARM range will appear on the screen. The warning range values are
selected by using the SCROLL UP/DOWN buttons to toggle the displayed
range in miles to the desired value. Pressing
the ENTER button stores the value in memory.
Once done, the AUDIBLE ALARM range will
automatically appear on the screen. Follow the same procedure to select
the value desired, and press ENTER to store in Memory. The unit will
then return to the Menu. NOTE: Once stored, these ALARM RANGE val-
ues will be stored in memory each time the unit is operated until changed.
NOTE: The audible tone may be turned ON or OFF at any time by using
the TONE ON/OFF button in the front of the unit (see page 2). This
will not change the alarm range stored in memory. Each time the unit is
turned on, the audible tone will be ON and must be turned OFF manually,
if so desired. See page 12 for more details.

10
3. ALARM MODE
This option allows for the setting of an additional trigger distance for an
audible alarm with a faster tone rate, which may be extremely useful for
certain applications. This feature allows the ThunderBolt
®
to automatical-
ly increase its alarm level as a storm approaches to a closer distance than
the range selected for normal storm detection. To set the ALARM MODE,
select ALARM MODE from the Menu, and follow the same procedure as
the ALARM RANGE. Once the value has been
stored, the unit will return to the Menu.
4. SENSITIVITY
There are two storm detection sensitivity settings: NORMAL and
HIGH (see the information following this paragraph for a descrip-
tion of each setting). Select SENSITIVITY from the Menu, and SET
SENSITIVITY will be displayed. To set HIGH, push the SCROLL UP
key. Or, to set NORMAL, push the SCROLL
DOWN key. Then press the ENTER key. The
setting is entered into the computer and
the memory is updated. ThunderBolt then
returns to the Menu, and then back to the SCANNING mode within 7
seconds if no further action is taken within the MENU.
SCANNING SENSITIVITY NORMAL: This setting produces the great-
er accuracy in storm tracking and speed calculation, but increases the
time between a storm first being detected, and a calculated speed and
Estimated Time of Arrival (ETA) being displayed.
SCANNING SENSITIVITY HIGH: This setting provides the fastest
possible information, but sacrifices accuracy for speed. The information
will gradually become more accurate as the unit gathers data. Use this
option in situations where maximum warning time is required to prepare
for storm arrival, or in certain indoor applications where the surrounding
building may be reducing the signal strength.
Both HIGH and NORMAL modes are effective and selection by the user
should be made based on preference and/or application needs.

1111
5. NOISE TEST
The purpose of the NOISE TEST is to detect and map the periodic,
non-storm, Electromagnetic Interference (EMI) in the planned operat-
ing location for the ThunderBolt
®
, so that the unit only recognizes the
electromagnetic activity of storm cells. There are numerous sources of
electromagnetic energy that exist in our environment, such as computers
and heavy machinery. Such non-storm related sources might result in
electromagnetic interference and cause the ThunderBolt to false-trigger,
subsequently displaying inaccurate readings. The unit contains special
software routines for detecting and minimizing “noise” from EMI sources.
To activate the NOISE TEST, select NOISE TEST from the Menu. NOISE
TEST, START/EXIT will appear on the screen.
The cursor will be blinking on EXIT. Push
either SCROLL UP or SCROLL DOWN button to
START, then push ENTER. The NOISE TEST will automatically begin and
can take up to 15 minutes to run. NOTE: Pressing ENTER, or any other
button, will stop the NOISE TEST routine before completion. No data will
have been stored and the test will need to be run from the beginning at
a later time. Once the NOISE TEST is completed, the unit automatically
returns to normal operation, and the ThunderBolt will then ignore these
background sources of EMI. NOTE: Some environments may be too
saturated with EMI emission for the unit to accurately function at all. If
there is too much background EMI, the WARNING: HIGH BACKGROUND
NOISE message will be displayed. Turn the unit off and move to a
different location, then restart the routine.
IMPORTANT! Each ThunderBolt has a NOISE TEST completed
prior to shipping, so it is not vital to run a test during the unit’s first use,
unless usage is in an obviously noisy environment. This is important
because a NOISE TEST should not be run if there is storm activity occur-
ring within 50 miles of your location. Doing so will introduce errors
and inaccuracy to normal operation and may decrease the sensitivity
of the unit. If possible, check other weather sources before running the
test. During the summer storm season in subtropical or tropical climates,
running the test during typical non-storm times of day is advisable.

12
6. BACKLIGHT ON/OFF
In ThunderBolt’s Main Menu, the user has the option to turn the
backlight ON or OFF.
IMPORTANT! When the unit is turned on for the first time, the
unit has been pre-set with the LCD backlight ON. When the backlight has
been turned OFF in the Main Menu, the backlight cannot be activated by
pushing the ENTER button. To reactivate the backlight, it must be turned
ON in the Main Menu.
NOTE: Regardless if the LCD backlight is programmed ON or OFF
(whether on battery or AC power) the LCD backlight will still illuminate
briefly during Power ON.

1313
AUDIBLE ALARM TONE OPERATION
The Tone may be turned ON or OFF anytime the normal scanning screen
is displayed by pressing the Tone ON/OFF button and holding it until
TONE IS NOW ON or TONE IS NOW OFF appears on the LCD screen.
Once storm activity has been detected you may turn the Tone ON or
Off by first pushing either the SCROLL UP or SCROLL DOWN button to
reenter the Menu. Next, push ENTER for the scanning screen to
reappear, and then press the Tone ON/OFF button as instructed in the
previous paragraph. The unit will then automatically return to Menu before
returning to normal scanning operation, and will then quickly resume the
current storm display.
OPERATION OF THE LCD SCREEN BACKLIGHT
ThunderBolt’s LCD screen has a built-in backlight for use in low light
situations. When the unit is on battery power, the user controls the use of
the backlight. This has been done by design to minimize the battery drain
caused by the required power consumption of the backlight. Operation of
the backlight is as follows:
BATTERY POWER INSTRUCTIONS
POWER ON: When the ThunderBolt is powered on, the LCD screen will
illuminate for approximately five seconds. The backlight will then turn off
and the unit will continue to boot, as described on page 7.
NORMAL SCANNING: When the unit is SCANNING, the LCD’s back-
light will be turned off. Under normal lighting conditions, the user may
read the SCANNING message on the LCD screen without the backlight
activated. Under low light situations, the user may at any time activate
the backlight by pressing the ENTER button. The backlight will illuminate
for approximately five seconds.

14
STORM DETECTION: As when SCANNING, the unit’s backlight will
remain off until the user activates the backlight, following the same pro-
cedure described in NORMAL SCANNING. When an approaching storm
activates the VISUAL and AUDIBLE ALARMS, the user may choose dur-
ing low light situations to activate the backlight to read the specific storm
information on the LCD text screen.
AC POWER INSTRUCTIONS
AC POWER: When ThunderBolt is running on AC power, the LCD
backlight will be illuminated continuously, unless otherwise turned off
through the Main Menu.

1515
BASIC UNIT OPERATION
STORM DETECTION
The ThunderBolt
®
detects and tracks the motion of storm cells by detect-
ing the lightning activity within the cell. The unit is capable of detecting
multiple storm cells within its 75-mile operating range, and is also capable
of identifying squall lines and severe storms. NOTE: ThunderBolt is pro-
grammed to report on the LCD screen only the closest approaching storm
cell to the user on its LCD screen.
Once in basic STORM SCANNING mode, the ThunderBolt warns of any
detected thunderstorm activity using text messages displayed on the
LCD. Depending on the exact type of weather situation being detected,
the information is displayed using a series of two-line messages on the
screen. These messages cycle approximately every 5 seconds, so that
any particular message will reappear within a short period. It is important
to remember that the ThunderBolt continually accumulates data from the
ongoing storm activity, and that more accurate information can be dis-
played with more data in the computer memory. This makes it important
to have the ThunderBolt operating for as long as possible before storm
activity is nearby. Don’t wait until you think storms are close before
turning on the unit! If the ThunderBolt is turned on with thun-
derstorm activity already close by, it may take several minutes
for the most accurate information to be calculated and displayed.
More importantly, the storm may already be LOCAL (within 8
miles of the user), putting the user in danger before ThunderBolt
can provide a warning.
IMPORTANT! Any time the ThunderBolt displays detected storm
activity immediately after power on, take extra precautions until enough
data has accumulated to give an accurate location of the storm. Storm
activity should be assumed to be LOCAL and appropriate precautions taken
until at least fifteen minutes of storm data has been allowed to accumulate.
This is especially important if the APPROXIMATE RANGES displayed are
20 miles or less!

1616
Once ThunderBolt
®
detects initial storm activity, the screen will display a
warning that strikes have been detected, and then the range in miles to the
last CLOSEST strike detected. This information will be displayed and updated
until enough data has been accumulated to display the range to the leading
edge of the storm, along with indication of storm motion. The time required
for accumulation of this data may vary depending on the actual levels of
activity within the storm. If no movement toward you has been detected,
a NO APPROACH DETECTED message will be displayed along with storm
distance. If the storm is approaching, the storm speed, along with
ETA, will be displayed.
IMPORTANT! The ETA displayed is the estimation of when the
leading edge of the storm activity will reach within 8 miles of your
location. This may happen without any obvious signs of storms being
directly overhead. Also note that storms may form directly over your
location, and that advance warning of these storms may be very limited.
The ThunderBolt continuosly analyzes the intensity of the storm activity
it detects, and attempts to provide additional warning about the presence
and approach of both squall lines and super-cells. Once detected, warn-
ings for these types of storms are displayed in the LCD. Extreme caution
should be taken if these warnings are displayed. Also note that storm cells
may evolve quickly from a normal cell into these more dangerous forms
of weather. Consult your local weather information sources, if available,
when the threats of these types of storms are present.
IMPORTANT! Keep in mind that all of the approach speeds and esti-
mated arrival times are based on data that the ThunderBolt accumulates over
periods of time. Thunderstorms can change both their intensity and
activity on very short notice. The information displayed by the
ThunderBolt must be used as an approximation that can change
quickly as the storm changes. Once any part of storm cell activity

1717
has been detected within 8 miles of your location, the screen display
will indicate STORM IS LOCAL. This means that lightning activity directly
overhead is now possible at any moment, and extreme precautions should
be taken! ThunderBolt
®
will maintain this warning until the detected
storm activity (the rear edge of the storm cell) recedes to a distance of
more than 8 miles.
Once a storm has become LOCAL, ThunderBolt will calculate and display
an estimated TIME TO CLEAR. Clearing a location means NO detected
storm activity within eight miles for 15 minutes. If any activity at all occurs
while the storm is LOCAL, the TIME TO CLEAR will reset itself. Note this
is only an estimate! The storm motion may change while still in your
vicinity, and the time for it to clear to a safe distance may change quickly.
IMPORTANT! The TIME TO CLEAR is updated continuously using
actual storm speed, as well as the approach of storms outside the 8-mile
local zone. These factors may cause the TIME TO CLEAR estimate to
change and lengthen once it begins. Also note that this is ONLY intended
as an estimate of the time necessary to completely clear dangerous activity
from your location. Storm motion and activity can occur faster than the
ThunderBolt can accumulate enough data for accurate estimates.
This time estimate is broken into 15-minute segments, and is updated as
storm data continues to be collected. The estimate displayed may change
or run longer based on the actual storm activity. This will often happen
with storms that develop directly overhead with very little associated
movement.

1818
IMPORTANT! Remember that most storms detected at ranges greater
than 20 miles will appear to be approaching, and will be given an ETA, until
enough data is accumulated to be certain of passing safely out of local dan-
ger range. In actual operation, this will mean that storms detected at long
range will appear to gradually veer off from your location. In actuality, the
ThunderBolt
®
may warn of a potential storm strike until enough data indi-
cates there is little or no possibility of a direct hit. For most storm situations,
the ThunderBolt will be able to determine the likelihood of a direct hit or near
pass from the storm by the time it has closed to within 15-20 miles. Storms
that display a range of less than 20 miles and an ETA of less than 30 minutes
are HIGH LEVEL threats and should trigger maximum safety responses.
TEXT MESSAGES
While in STORM DETECT mode, ThunderBolt has been programmed to
communicate certain messages during specific weather conditions. In nor-
mal operation, the user will see a repeating series of messages specific to
that situation. Messages cycle approximately every 10 seconds so that any
particular message will reappear within a short period. The typical text mes-
sages that will appear during various situations are listed and defined below:
ThunderBolt is scanning in the SENSITIVITY HIGH mode and has not detected
any storm activity. See page 10 for more detail on SENSITIVITY HIGH.
ThunderBolt is scanning in the SENSITIVITY NORMAL mode and has not
detected any storm activity. See page 10 for more detail on SENSITIVITY
NORMAL.

1919
ThunderBolt
®
has detected initial lightning activity.
This display represents the closest detected stroke during the period of
initial data collection. The number indicated is the number of miles the
lightning stroke occurs from the user.
ThunderBolt has plotted the storm location. Storm approach and ETA will
follow if the storm is approaching. The number indicated is the distance in
miles the storm is occurring from the user.
A severe storm has been detected. Remember to check other weather
sources for additional information and advisories.
ThunderBolt has detected the presence of squall lines or multiple storm
cells. The user will receive information on the storm closest to his/her
location. Exercise extreme caution when these conditions are indicated.
Both can result in high winds and tornado activity.
The speed of the approaching storm has been indicated. This information
does not always mean the storm will reach the user. Storms are unpredict-
able and can suddenly change direction or totally dissipate.

2020
ThunderBolt
®
has calculated the storm distance and approach speed and
determined, based on current conditions, that the storm will reach striking
distance of the user in the time indicated on the screen.
The storm has moved within eight miles and is now within striking dis-
tance of the user. SEEK SAFE SHELTER!
NOTE: The user may not yet hear thunder or see lightning (perhaps looking
at blue sky/non-threatening conditions) as the storm may be on the edge
of the 8-mile range and cannot yet be detected by sight or hearing.
This is not a common screen and will appear only when a storm devel-
ops within the 8-mile LOCAL range. There will not be any previous storm
warning on the unit because the storm developed within this range. This
occurrence is more common in subtropical and tropical regions when
small storm cells can develop rapidly during the summer season.
Once storm activity has become LOCAL (within 8 miles of user) the
ThunderBolt will indicate, based on current conditions, the amount of
time in minutes it will take for the storm to safely clear the eight mile
range. The unit is limited to four time frames (LESS THAN 15, 15-
30, 30-45, and MORE THAN 45 MINUTES). Once this time appears,
ThunderBolt internally begins a countdown of this time. If during this
countdown, the unit detects any new lightning strokes within the
8-mile range, it will automatically reset the time back to the time it
originally indicated. Therefore, the TIME TO CLEAR time can be greater
than indicated as the unit detects new activity.