We have had great turnouts to the Skywarn classes this Spring, and want to thank all of those who showed up and for the Emergency Managers for getting the word spread about these classes.
We have already seen the Spring Season produce severe weather over portions of our forecast area. Wednesday, March 24th, severe thunderstorms developed across the New River Valley, east into the Virginia foothills and south into the North Carolina piedmont and foothills. These storms produced mainly large hail, and isolated damaging winds.
The trained weather spotter is crucial in relaying weather reports to the National Weather Service. Your reports help us inform the general public, your neighbors, of potentially hazardous weather conditions. Satellite and radar can only tell us so much, but the spotter is the trained eye on the ground letting us know, if that specific storm is producing large hail, or wind gusts to 60 mph, or even a tornado.
April through August is when our area, Southeast West Virginia, Southwest Virginia, and Northwest North Carolina, experiences most of its severe weather during the year. Below are some helpful guidelines and links for you to use when reporting severe weather to the National Weather Service.
The following is a list of what we would like for spotters to report:
1) Wind speeds in excess of 40 mph
2) Any hail size
3) A funnel cloud and/or tornado
4) Heavy rains, measurement of 1/2 inch in a half hour or 1 inch in an hour
5) Any damage caused by winds or lightning.
6) Flooding (Ex. Several feet of water covering the roads, mudslides, streams or creeks overflowing their banks). If you live near a creek or stream, and it is rising rapidly, report that to us as well, once it gets about 3/4 bankful.
NOTE: DO NOT RISK YOU LIVES IN TRYING TO GET SEVERE WEATHER REPORTS TO US!
Winds:
First off, if you do not have an anemometer, which is a wind speed measuring device, and want to estimate how strong the winds are blowing, use the following chart, called the Beaufort Wind Scale.
MPH |
Beaufort Wind Speed Evaluation Chart |
| 0 | Smoke rises vertically |
1-3 |
Direction of wind shown by smoke drift but not by wind vanes |
| 4-7 | Wind felt on face, leaves rustle, ordinary wind vane moved by wind |
| 8-12 | Leaves and small twigs in motion, light flags extended |
| 13-18 | Dust raised, loose paper raised, small branches move |
| 19-24 | Small leafy tress sway, crested wavelets form on lakes and ponds |
| 25-31 | Large branches in motion, whistling in telephone wires or link fences |
| 32-38 | Whole trees in motion, inconvenience felt walking against wind |
| 39-46 | Twigs break off trees, impedes progress walking |
| 47-54 | Small branches break off dead or diseased trees |
| 55-63 | Slight structural damage (chimneys and shingles), branches break off healthy trees with leaves |
| 64-72 | Large branches of trees broken off, trees with leaves uprooted, structural damage mostly to roofs |
| 73+ | Damage to structures major and widespread, many roofs and windows damaged |
Hail:
Secondly, here is a guide for determining hail size. Report the largest hail stone that you see. Also, try not to report the hail size as marbles. Marble can come in any size, so try to estimate the size to what the chart below shows.
|
|
| 1/4"
|
Pea Size
|
| 3/4" (Severe Criteria)
| Penny
Size |
| 7/8"
|
Nickel Size
|
| 1"
|
Quarter Size
|
| 1 1/4"
|
Half Dollar Size
|
| 1 1/2"
|
Walnut or Ping Pong Ball Size
|
| 1 3/4"
|
Golf Ball Size
|
| 2"
|
Hen Egg Size
|
| 2 1/2"
|
Tennis Ball Size
|
| 2 3/4"
|
Baseball Size
|
| 3"
|
Teacup Size
|
| 4"
|
Grapefruit Size
|
| 4 1/2"
|
Softball Size
|
Tornadoes:
A tornado is a rapidly rotating column of air that extends to
and is in contact with the ground. Remember, sometimes the funnel may
not be visible all the way to the surface, but the key is to look at the
ground, and if you see debris or dust being kicked up, and rotation, then
it is already a tornado. The Fujita Scale is used to relate the degree
of damage to the intensity of the wind.