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 HOW
TO LOOK FOR SPRITES, BLUE JETS AND UPWARD LIGHTNING
Whenever thunderstorms
are around, it is possible, with a little luck, to spot a “transient
luminous event” above the storm. Sometimes you might not even be
looking intentionally, and it just happens. Below we summarize the basics
of what to look for and how to interpret what you may have have seen.
Your reports are
valuable. If you can provide enough detail, it can help researchers
better understand the types of storms that produce these phenomena. And
we are really, really interested in reports of upward discharges from
thunderstorm tops such as blue jets and upward lightning. Also, “ball
lightning” is a subject that is again gaining interest from the atmospheric
electricty community. If you believe you have seen such a phenomenon,
please let us know and we will forward your report to the appropriate
researchers.
If you have obtained
still images or video, then your observations would be especially valuable
to helping advancing scientific study of these events
If you have an
observation you wish to contribute to the growing base of reports from
amatuers and professionals alike, click here.
General
Rules: Most optical transients above thunderstorms are
fairly dim (with the exception of upward lightning.)
So, once you have checked out the satellite and radar maps to locate storms
within range of your location, the following will help improve your chances:
Moonless nights are preferred.
Rural locations far from urban light pollution are optimal.
Select nights with a minimum of haze, smoke or pollution
in the atmosphere.
It is best to let your eyes become dark-adapted for five or ten minutes.
If the lightning from the storm system is visible,
it may be best to block out their glare to enhance chances of seeing the
dimmer features above.
Sometimes you have better luck by looking off to the side of the storm
as you can see dimly illuminated objects better out of the corner of your
eye.
Have a watch set to the second to obtain an accurate
time for any event.
Listen to an AM radio (tuned to an unused frequency near the low end of
the band). Sprites may coincide with unusual or strong bursts of static
(called “sferics”)
Bring a chair, and perhaps something to support
your head, while watching.
If you have a “night scope,” which are becoming increasingly
inexpensive, use it. Many sprites show up very clearly even on older surplus
units.
RED SPRITES
Appearance: curtains or streaks, rather like
an aurora.
Color: salmon red, but sometimes people see
them as white or green.
Duration: really fast! Literally about the
blink of eye.
Frequency: in active storms, every one or
two minutes possible; 5 mintutes more common. Most storms “sprite”
for several hours once they start.
Relation to lightning: appears simultaenous
with bright flash in cloud if storm not too far away.
Type of thunderstorms: very large thunderstorm
system and complex squall lines.
Size of thunderstorm: the storm should be
at least the size of the state of Connecticut.
Portion of thunderstorm: above the weaker
radar echeos, often trailing behind the intense leading edge.
Look well above the storm top (2 to 4 times the height of the storm.)
When in life cycle: mature and late mature
stages of storm.
Range to storm: best for storm to be 100
to 300 miles away.
Best part of country: anywhere east of Rockies
in summer, especially the Central and Northern Plains.
Best time: whenever dark, but 10 PM to midnight
seems to be the best bet.
AM radio static: sprite will often be coincident
with loudest radio static.
Photography:
set video camera on widest aperture and let run - brightest may be faintly
vsible. Sprites probably not detectable
on still imagers.
BLUE
JETS
Appearance: a cone-shaped, upward moving
fountain of light, often brighter on top. May be at angle to vertical.
Color: dim blue.
Duration: about a quarter of a second; just
slow enough to sense upward motion.
Frequency: sometimes a singular event; others
every minute or so for an hour or more.
Relation to lightning: usually above electrically
active part of stom but unrelated to specifc flashes.
Type of thunderstorms: more intense storms,
possibly related to tornadoes and hail (supercells.)
Size of thunderstorm: generally smaller storms
(supercells), or individual cells in squall lines.
Portion of thunderstorm: near the highest
portion of cloud, perhaps near overshooting dome.
When in life cycle: probably in growth and
early mature phase.
Range to storm: best within 100 miles (blue
light does not transmit well though the atmosphere.)
Best part of country: Central US, but maybe
storms over ocean and Gulf Stream as well.
Best time: at night, in order to see dim
blue light.
AM radio static: not related to specific
static, but storm likely to be very active.
Photography:
set video camera on widest aperture and let run; set for time exposures
on still cameras; use a tripod.
UPWARD
LIGHTNING
Appearance: similar to a conventional lightning
bolt, generally rather straight, may be tilted off vertical axis;does
not flicker like cloud-to-ground flashes.
Color: yellow or white lightning channel,
maybe with blue flames above.
Duration: unusually long? Some reports of
one, two and even 5 seconds duration.
Frequency: seems to occur every several minutes,
sometimes for 40 minutes or more.
Relation to lightning: unknown; storms may
have very high to almost zero lightning rates.
Type of thunderstorms: supercells, tornadic
storms; rapidly growing cells with cauliflower tops.
Size of thunderstorm: smaller (10s of miles
across), especially those associated with severe weather.
Portion of thunderstorm: above the highest
part of thunderstom - may see cauliflower dome protuding into stratosphere
When in life cycle: most likely when storm
is young and in maximum growth stage.
Range to storm: nearby storms best, perhaps
visible to 100-200 miles away.
Best part of country: Central US and very
possibly along Gulf and Atlantic coastal areas.
Best time: anytime? brilliant enough to be
visible both day and night.
AM radio static: storm may have active static,
but may not be required.
Photography:
set video camera on widest aperture and let run; set for time exposures
on still cameras; use a tripod.
DON'T
BE FOOLED!
So-called “heat lightning” can sometimes be mistaken for sprites
or even blue jets. Heat lightning is nothing more than the reflection
of regular lightning occurring within distant thunderstorms largely below
the horizon. Its color can range from white to blue and even reddish.
It can be fan shaped. A rate of several flashes per minute or more may
be a tip off.
OTHER
PHENOMENA
Ball lightning is extremely rare - so rare that some scientists don’t
really believe it exists. It often follows a nearby lightning strike.
The glowing plasma can drift or dart around, lasts for seconds to minutes,
comes in a variety of colors, often can appear to go through walls, sometimes
makes hissing noises…and is completely weird. If you have an encounter
with ball lightning, we’d love to hear from you. If you get a picture…you’ll
be famous!
Recent reports have
suggested unusual electrical effects near thunderstorms, especially tornadic
supercells. These events appear as fast moving streaks of light, often
with a bright leading glow. Several still and video images have been obtained
in recent years, but it is not clear whether they may not be an artifact
of newer types of CCD imaging systems now in widespread use. If you see
and/or photograph such a strange shooting streak of light below the base
of the cloud, we would really like to hear about it.
If you see a nice
aurora, the folks at www. SpaceWeather.com would like to hear from you.
And if you see something
that just doesn’t fit anything we discussed on this web site, do
your best to describe it and let us know.
But…we don’t
do UFOs, little green men, mystical events, ghosts or the supernatural
here. We just do scientific observations of atmospheric electricity and
related phenomena.
CLICK
HERE TO GO TO THE REPORTING FORM
Satellite: This is an infrared (heat) image of the clouds over the U.S.
The higher the cloud top, the colder it is. The coldest clouds in this
display are the darkest blue. Reddish areas usually represent clear skies.
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