National Weather Service Office Charleston
1, Issue 5
5777 S. Aviation Ave. Charleston, SC 29406 Editor- Robert Crapulli
803-744-0303 Spotter reports..... 800-897-0823 Internet: wchs.csc.noaa.gov
An Open Letter to Charleston's Severe Weather Spotters
As we come to the end of summer and the convective season, we look forward to a "quiet" off-season. However, convective storms still can occur during the fall months, and even the winter months.
During this time of the year, reports from spotters are still very much appreciated. The National Weather Service (NWS) needs your reports any time of day or night, in the summer and winter months. The effort that most of you, as our good neighbors, put into the SKYWARN Program to help your "neighbor" is commendable. Your reports have been timely and assisted us tremendously in issuing and verifying warnings.
I'm sure that when you first became a part of our network, you were excited to become an ally of the NWS. We would like to work with each of you to keep that interest as high as possible. Sometimes our interests begin to wane after a couple of years for whatever reason. The Charleston office wants to rekindle the early flame that you exhibited by conducting follow-up spotter training classes. The classes would be for anyone who has not gone through the training at least twice and received their training before January 1, 1996.
Those of you who have taken the class twice already, may want to schedule an advanced class. It is our hope that we can schedule all refresher and/or advanced classes prior to the 1998 Georgia/South Carolina tornado season (March - May). So do not delay and begin making plans in your group to decide the most convenient time to schedule a class for maximum attendance. You may contact either John Simensky or me at 800-897-0823, or locally at 554-0197. Your cooperation in this matter will be greatly appreciated. A reminder..Please let us know if your address or phone number has changed, so that we may keep our spotters' list current.
Again, thanks for all that each of you do to help us to be the best National Weather Service office that we can be.
NWS Criteria used to
verify weather warnings
In This Issue...
1...Letter to Spotters / Warning Criteria
Area Weather Summary
June - Record setting low temperatures combined with average daily temperatures up to 15 degrees below normal welcomed the first full week of the month. The high temperatures were also records - record low maximums. A persistent cool spring weather pattern over the Southeast U.S. was responsible for this unseasonal weather. Plenty of warnings were issued and severe weather reports were received on many of these storms. Reports included one-inch hail covering the ground in Charleston County (Airport and Ladson). Heavy rainfall produced significant flooding on several days. A record setting 4.91 inches fell at Charleston Airport on the sixth. Almost ten inches fell in Mt. Pleasant, while other Charleston suburbs north of the city received up to eight inches of rain in a few hours. Flooding affected the usual low-lying areas of Downtown Charleston. Another event on the 28th left six to seven feet of water covering roads in North Charleston's Otranto subdivision. Other severe events (indicated by Doppler radar and local Weather Spotters) included severe thunderstorm winds that knocked down trees and power lines. June was an active month for severe weather, but even on quiet rain free days, readings of 90 degrees or more were infrequent throughout the Lowcountry and Coastal Empire.
July - On July 4th a record high of 99 degrees was set at Savannah. The first heat wave of the season came just in time for the holiday weekend. The temperature reached 97 degrees at Charleston, and high humidity values pushed the Heat Index to dangerous levels of 115 degrees or higher. Severe weather was noted with typical late afternoon seabreeze thunderstorms forming along the coast. Baseball-size hail fell in Bulloch County on the third. One-inch hail was reported on the eighth by a Weather Spotter in Dorchester County. Many severe thunderstorm warnings were issued from the 16th - 18th. Reports included downed trees, power lines, and numerous occurrences of structural damage to businesses (on the 16th) in Savannah and Charleston. In Dorchester County (St. George) a woman was struck by lightning on the 17th. On the 31st, 6.7 inches of rain (2-day total) fell in Downtown Savannah. Totals ranged from
two to six inches throughout Southeast GA/SC. July ended on a cool note with record low maximums and minimums set at the Charleston and Savannah airports.
August - Temperatures again averaged below normal for the fifth month in a row. March was the last month in which readings were (significantly) above normal. August was also a very dry month, as the typical seabreeze thunderstorms did not provide for much rainfall over a significant area. The lack of precipitation or severe weather made for a somewhat quiet month weatherwise. There were a few active days, however. One-inch hail fell in Shulerville (Berkeley County) on the fifth. Police in St. George reported nickel size hail. Numerous reports of downed trees were located in Colleton County. A cold front managed to reach the Deep South, and it was responsible for the severe thunderstorms on this date. This is very unusual for August. A similar weather situation occurred on the 16th with reports of downed trees and small hail in Colleton County, near Walterboro. Other wind damage reports were received from Hampton County on this day. On the 30th, Savannah Airport received one-half inch hail, with some storms along the coastal counties responsible for localized rainfall amounts up to 2.5 inches. Wind damage also affected the Hardeeville area .
Area Weather Statistics
CHS = Charleston International Airport
What in the World is a Radiosonde?
A radiosonde contains sensors which transmit radio signals to a ground tracking station. The instrument is powered by a small dry-cell battery and is housed in a casing of Styrofoam the size of a shoe box. A Hydrogen-filled balloon provides the lift needed to carry the radiosonde upward, and a three dimensional observation of pressure, humidity, and air temperature is taken. Wind speed and direction are calculated by figuring the instrument's position relative to the ground tracking station. The radiosonde rises to heights up to 20 miles above the Earth's surface and then a parachute carries the reusable instrument to the ground after the balloon bursts. Data that are received by a ground station is transmitted by phone modem to a supercomputer center in Washington D.C. A national and worldwide network of sites that take upper air observations allow construction of forecast maps, graphics, and charts.
Weather forecasters attempted to collect data at levels above the surface in the earlier decades of this century so that weather systems could be detected and analyzed. Early methods of upper-air data collection included attaching instruments to balloons and tethering them to the ground. One problem encountered was height limitations. Another was the occasional broken tethered line that caused property damage and lost data. Another method attached weather instruments to airplanes, but the data could not be retrieved until the plane landed...hours or even days later.
The radiosonde's development, like many other inventions, was not confined to the United States. France and Germany developed upper air observing devices by 1921. German scientists conducted a 20 minute flight in 1922, and weather forecasters in France obtained several successful observations around this time period. The Russians designed the most successful type of radiosonde before the mid 1930s. Radiosondes in use today are the result of the combined research efforts of university and National Weather Service (NWS) scientists.
Thanks to the efforts of these early inventors and NWS employees, the radiosonde has helped to produce a successful upper air observing system.
New Rules on Electronic Eavesdropping
Amendments to the Communications act of 1934 seek to prohibit scanning receivers from being used for frequencies that are allocated to commercial mobile services. If passed, scanners could not be altered to receive such frequencies, nor may they be equipped to decode digital commercial mobile transmissions to analog voice audio. --"Wireless Privacy Enhancement Act of 1997". You may want to contact your congressman's office to find out the status of HR2369.
These codes are used by radios with SAME technology. Your radio alerts only if your county is warned and the radio is programmed with the correct code. For more info see:
GA County Codes...
Bryan, 029 ; Bulloch, 031 ; Candler, 043 ; Chatham, 051 ; Effingham, 103 ; Evans, 109 ; Jenkins, 165 ; Liberty, 179 ; Long , 183 ; Mcintosh, 191 ; Screven, 251 ; Tattnall, 267.
SC County Codes...
Allendale, 005 ; Beaufort, 013 ; Berkely, 015 ; Charleston, 019 ; Colleton, 029 ; Dorchester, 035 ; Hampton, 045 ; Jasper, 053.
Quarterly Spotter Reports
1. Robert & Emily
Thanks to the weather spotters who provided us
We now have 28 Co-Op observers reporting daily high and low temperatures along with rainfall through the ROSA system. These daily reports have proven to be a valuable resource in forecasts for river levels. The reports are used to verify the new Doppler Radar rainfall data. The National Weather Service in Charleston appreciates the job you are doing.
Three new observing sites have joined the network recently.
Lynne & John Evans of Newington, GA
Chief Hood and Old Fort Fire Dept. in Ladson, SC
James Fuller and City Water Dept. of Ludowici, GA
I would like to thank all Cooperative observers for sending in the Observations forms early each month. All reports are being received at the National Climatic Center by the cut off date. This allows the Center to prepare the temperature and rainfall charts for Georgia and South Carolina early for use by various agencies across the Southeast.
Bob Simpson - Cooperative Program Manager
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