Severe Weather Awareness Week - Tuesday Statement

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Public Information Statement
National Weather Service Gray ME
732 AM EDT Tue Apr 30 2019

The National Weather Service has declared the week of April
29th through May 3th...SEVERE WEATHER AWARENESS WEEK in New
England. This is the second in a series of five Public
Information Statements on various topics related to severe
weather awareness.

...SEVERE WEATHER AWARENESS - THUNDERSTORMS AND LIGHTNING...

Summertime is a good time for outdoor recreational activities in
New England; it is also the time of the year when thunderstorms
are most likely. Thunderstorms can be beautiful to observe, but
they also can be deadly. While many people think they are aware
of the dangers of thunderstorms and lightning, the vast majority
are not.

There are three basic ingredients needed for the formation of a
thunderstorm: low-level moisture, an unstable atmosphere, and a
source of lift.

Low-Level Moisture: Moisture near the surface is needed for
cloud formation and growth, and the development of precipitation
within the cloud.

Unstable Atmosphere: An unstable atmosphere allows warm, moist
air near the ground to rise rapidly to higher levels in the
atmosphere where temperatures are colder. An unstable atmosphere
also allows air at higher levels in the atmosphere to sink to
the ground rapidly, bringing stronger winds from above to the
ground.

Source of Lift: Something to set the atmosphere in motion,
particularly in an upward direction.

All three ingredients contribute to the formation of thunder-
storms. In fact, as the magnitudes of these ingredients
increase, so do the chances that any thunderstorms that develop
could become severe. Especially in the summertime, listen to the
latest forecast and learn to recognize the signs that often
precede thunderstorm development.

Warm, muggy air is a sign that ample low-level moisture is
available for thunderstorm development. Towering cumulus clouds
indicate an atmosphere that is, or is becoming, unstable. And a
source of lift could develop by continued heating from the sun;
an approaching warm, cold, or sea breeze front; or a cooling of
the upper atmosphere.

All thunderstorms go through various stages of growth and
development. As a thunderstorm cloud continues to grow, snow and
ice begin to form in the middle and higher levels of the cloud
where temperatures are below freezing, and electrical charges
start to build up within the cloud. Negative electrical charges
near the middle of the thunderstorm cloud cause positive charges
to build up on the ground under and near the thunderstorm.
Finally, when the difference between these charges becomes too
great, a giant atmospheric spark we call lightning occurs.

Lightning is an underrated killer, usually claiming its victims
one at a time; it also leaves many victims with serious or even
life-long injuries. Lightning can strike as far as 10 miles from
the side of a thunderstorm cloud. In fact, many lightning
victims are struck before the rain arrives or after the rain has
ended; many victims also report that at least a portion of the
sky was blue when they were struck. During the past 10 years,
neither Maine or New Hampshire have had any lightning fatalities.
Although Maine has less lightning than most states east of the
Rocky Mountains, Maine ranks rather high in terms of lightning
deaths per capita.

Although more information on lightning and lightning safety will
be provided during Lightning Safety Awareness Week, the last
full week in June, here are some basic tips to help keep you and
your family safe this summer.

WHILE INSIDE A HOME OR BUILDING...

1. Avoid any contact with electrical or electronic equipment
     or cords that are plugged into an electrical system.
2. Avoid any contact with corded phones.
3. Avoid any contact with the plumbing system. Do not wash
     your hands, do not wash the dishes, do not take a shower,
     and do not do laundry.
4. Do not stand next to a concrete wall and do not lie on a
     concrete floor.
5. Stay away from windows, outside doorways, and porches.

WHILE OUTDOORS...

1. There is no safe place outside in a thunderstorm. To be
     safe, you must get inside a substantial building or hard-
     topped metal vehicle.
2. Plan outside activities so that you minimize the risk of
     being caught outside in a thunderstorm.
3. If you hear thunder, get to a safe place immediately.
     Generally, if you can hear the thunder, you`re within
     striking distance of any lightning from the storm.
4. If the sky looks threatening, move inside immediately.
     Don`t wait for the first flash of lightning. It could occur
     anywhere under or near the storm.
5. Stay inside a safe place for at least 30 minutes after the
     last rumble of thunder was heard. Many lightning victims
     are struck after the worst part of a storm has passed.

Remember, when it comes to thunderstorm safety, it`s your own
actions that will determine your personal risk of being killed
or seriously injured by the hazards that accompany
thunderstorms.

Here is a list of the topics that have been or will be covered
in Public Information Statements issued by the National Weather
Service this week.

Monday......Some Basic Definitions
Wednesday...Severe Thunderstorms - Downbursts, Microbursts,
            and Hail
Thursday....Tornadoes
Friday......Flash Floods

$$

Watson
National Weather Service
Gray, Maine