SKY SCOOP

Spring/Summer 1997

Issue #2





The Great Flood Of 1997

During the first 10 days of March, portions of southern Ohio and Northern Kentucky received the worst river flooding in the past 33 years. For people living along the Licking river especially in Falmouth and Butler Kentucky as well as the Ohio Brush Creek in West Union Ohio, the river levels rose above or near the flood of record. The Ohio Brush Creek at West Union crested at approximately 31 feet which is only 2 feet below the flood of record. For the Licking river at Falmouth however, the estimated crest was between 50 and 51 feet. The previous flood of record for this location was 47.1 feet, over 3 feet below the 1997 crest.

The flash flooding began around 8 AM on Saturday March 1st. By that evening though, virtually all of Falmouth and Butler KY had been evacuated. Unfortunately by the end of the event, nearly 80 percent of the homes and businesses in Falmouth were destroyed or had sustained major damage. Also, 5 people were killed in the Falmouth area, all because they attempted to return to their home after being evacuated. A total of 13 deaths occurred in Wilmington's county warning area due to flooding and flash flooding.

You, as spotters, performed excellently in reporting rainfall and flooding information to Wilmington throughout the event. As many people probably already know, an estimated amount of over 10 inches of rain fell across 7 counties in both Ohio and Kentucky during a 36 hour period. This excessive amount of rainfall is a very rare occurrence; consequently, your rainfall reports were especially helpful in trying to calibrate the radar precipitation estimates. Without your reports to verify the radar estimates, it may have been difficult for us to believe the severity of the event. One spotter in particular, Brenda Booher informed us that 5.2 inches of rain had fallen in Falmouth between 11 PM February 28th and noon on March 1st. Another spotter in Brown county Ohio also assisted greatly by informing us that 5 inches of rain had fallen near Ripley by noon on March 1st.

The information we received about the flooding was also quite helpful in the issuance of the flash flood and flood warnings. Spotters from Robertson, Pendleton, and Grant Counties in Kentucky as well as in Brown and Adams Counties in Ohio all indicated that extensive flooding occurred along creeks and streams throughout the day on Saturday, March 1st. The spotters in Adams and Grant Counties also informed us of the numerous evacuations in their areas. With this information, we were better able to describe the extent of the flooding in the warnings and flood statements.

Without your dedication and assistance during the flood of '97, the devastation and destruction would have been much more extensive and deadly.





Wilmington Ohio Pager System

For the past two years, the Wilmington office has offered to Emergency Management Officials as well as members of fire and police departments a weather pager service. However, we are now able to expand this service to the members of the Skywarn organization.

The purpose of this system is to be a secondary means of receiving warning or watch information. Presently, we are able to offer these services through Pagenet and USA Mobile. Both Pagenet and USA Mobile have agreed to offer the pager packages at special rates for those who desire to join. Also, depending upon the company, other services or packages are available with the pagers.

The advantage to this system is that if you are away from any other method of receiving weather information, you can receive warning and watch information via a pager when threatening weather is moving into the region.

Currently, Wilmington's 56 counties are divided into nine different groups. Each group has been assigned a code number so when a warning is sent out for any county in that group, the information will go to the pagers which are coded with that specific number. The pages are issued at anytime for the following products: severe thunderstorm and tornado watches, severe thunderstorm, tornado, and flash/flood warnings, winter storm, ice storm, blizzard, heavy snow, and snow squall warnings, as well as a high wind warning. Also, pages are issued between the hours of 8 AM to 10 PM for the following products: river flood warning, winter storm watch, high wind warning, flood/flash flood watch, winter weather, snow, and freezing advisories, wind and wind chill advisories, fog advisory, heat advisory, and flood potential outlook.

If you are interested in obtaining this service please refer to the enclosed information sheets from both Pagenet and USA Mobile. Note that this special service is only for Emergency Management Officals and spotters; thus, please do not give the information on these sheets to your friends and family. Once you decide on a company, you will need to either obtain a pager or have the service added to your pager agreement. In order for the pager to be encoded, you will need to first show the representative your Skywarn ID card so that he/she can verify that you a member of the Skywarn organization. You will also need to tell the representative the county for which you desire to receive information. Also on the back of the USA Mobile sheet is information which you will need when obtaining the pager. This sheet contains information about the specific pager styles and codes for the county groups for USA Mobile only.

Even though the pager system is convenient, as stated before, this system should only be considered as a secondary means of receiving warning and watch information. Unfortunately, since we are unable to control the time span it takes to transfer information from the pager company to the pager, we cannot guarantee that you will receive the information minutes after the warning is issued. Thus, we recommend that you you still use some other mechanism such as a NOAA weather radio as your primary avenue for weather information.

By the end of the event, nearly 80 percent of the homes and businesses in Falmouth were destroyed or had sustained major damage.





Letter From the Editor

As this year's spotter training season comes to a close, I would like to thank everyone who attended a seminar this year. For those of you who did not attend, the talk was changed somewhat. We added a new film as well as tried to focus the slide presentation more toward the types of storms which you, as spotters, will likely see. For example we added more detail on the characteristics of a squall line rather than spending as much time on a classic supercell thunderstorm.

If you were unable to attend a talk, you will find enclosed a questionnaire. If you could complete the form and return it in the self-addressed stamped envelope, I will then be able to update and verify your information in the spotter database. Each person is entered individually, so if only one person from your residence attended a talk, the remaining skywarn member(s) needs to complete the form(s). As always, if you have any questions, feel free to call at (937) 383-0031 or e-mail me at Diane.Innes@noaa.gov.

One last note, if you were unable to attend a meeting this spring, I strongly urge that you attend one next year. We would like all of our spotters to attend a meeting once every two to three years for a refresher on severe weather warning signs. If you are unable to attend one within this time frame, and do not contact us to let us know that you are still interested , your name will be dropped from the database. This is necessary to keep the spotter information up to date.





New Emergency Alert System

The new automated EAS system should improve the time which it takes for warnings to be aired.

On January 1, 1997, the new Emergency Alert System (EAS) replaced the old Emergency Broadcast System (EBS) for radio and television stations. Cable systems must convert to the new EAS system by around July 1, 1997.

The new EAS system is an automated system while the old EBS system was a manual system. The National Weather Service uses the NOAA Weather Radio (NWR) as its interface with the EAS system. New technology added to the NWR called the Specific Area Message Encoder (SAME) allows us to use digital data bursts to send coded information for specific severe weather events. This data includes information on the type of warning, the county the warning is valid for, the issue time, as well as the length of valid time. Radio stations, television stations, or local county officials who have decoders receive the NWR EAS transmission. These decoders can automatically record the voice transmission of the warning. Radio and television stations in the EAS network can broadcast and relay the warning.

Local county officials may also have the capability to encode messages that can be broadcast on the EAS network. For example, local counties may wish to put information about hazardous material spills on the EAS network.

The new automated EAS system should improve the time which it takes for warnings to be aired. It also provides a way for warnings to be broadcast over radio or television stations that are unattended at night.

The technology that allows NWR to interface with the EAS system will also allow for programmable NWR receives. These programmable NWR receivers will allow you to decide which watches or warnings you want to be alerted for and for which county(s) you would like these alerts. This would mean that you could set your receiver to only alert for watches and warnings for your county if you wish. We hope to see these programmable NWR receivers on the consumer market by the end of this year.

By Mary Jo Parker, WCM





The Devastating Flood of '97: A Meteorologist's Perspective

The presence of this abundant moisture along with a nearly stationary boundary combined to cause very heavy rainfall for greater than a 24 hour period.

Just preceding the Great Flood of '97, ironically much of the weather attention was focused on West Central Ohio. Rainfall had been abundant in this area, and flooding was occurring on the Blanchard, Maumee, Auglaize, and St. Marys rivers. Meanwhile, nearly all the other river levels were low across Southeast Indiana, Southern Ohio, and Northern Kentucky. The computer forecast maps Thursday morning, February 27th showed that conditions were favorable for heavy rains over the upcoming weekend. The big question was exactly how much rain would occur? By late Friday, the computer guidance suggested between 1.5 and 2.5 inches of rainfall would occur near and south of the Ohio River. The computer maps were on the right track, but the heaviest rainfall amounts were grossly underestimated. Between Friday night and Sunday, a record amount of rain fell. Actual rainfall amounts ranged between 8 and 12 inches across Northern Kentucky and far South Central Ohio.

The next question to ask was what happened meteorologically to bring such a deluge to the Ohio Valley? The most important feature was a strong and persistent southwesterly flow aloft that transported moisture rich air rapidly into the Ohio Valley. At 4000-5000 Feet above the ground, winds were howling at 50 to 70 MPH! These strong winds carried deep moisture into the Ohio River Valley in less time than driving the approximately 700 miles from the Gulf Coast, assuming that you stopped for lunch. In the Ohio Valley, if you were to take a small column of air that extended through much of the atmosphere and compared it to a typical column of air for early March, you would have found that during the Great Flood the air column contained nearly four times the normal amount of moisture. The presence of this abundant moisture along with a nearly stationary boundary combined to cause very heavy rainfall for greater than a 24 hour period.

The computer guidance did not do a good job in forecasting a low pressure center that developed near Arkansas early Saturday, March 1st, that later tracked into the Ohio Valley. This low further enhanced the precipitation development over the flood ravaged areas. The atmosphere continued to destabilize and thunderstorms developed creating even more boundaries. These boundaries combined with the nearly stationary front, and caused the rain to move over the same areas for a long period of time. Also since the computer forecasts erroneously moved the front northward, the maximum rainfall generated by the computer guidance was too low. However, the timing of the rainfall and where the heavier rain would occur was handled better by the computers.

The northern edge of the excessive rainfall had a sharp cuttoff. Thus, if the warm front had moved a little farther north, the heavy rain would have occurred over a larger area. Flooding would still have occurred, but maybe not the complete devastation that struck towns near the Ohio and Licking rivers. Another hard hit area was along the Ohio Brush Creek in South Central Ohio. Flash flooding occurred there where the river rose 16 feet above its flood stage! In the town of West Union in Adams county Ohio, 9.42 inches of rain was recorded during the weekend.

The Great Flood of '97 is the worst flooding that the Ohio Valley has seen in the past 33 years. As National Weather Service meteorologists , our mission is to issue warnings that save lives and help protect property. Although, rainfall as high as 1 foot was not expected, there were many timely flash flood and river flood warnings issued by our office that met our mission goals.

By Ryan Sandler, ILN Meteorologist





Welcome To New Spotters

This spring's spotter talks were extremely productive. Not only did older members come to refresh their memory on the warning signs of severe weather but we had many new faces attend as well. We added approximately 700 new members to the spotter program this year.

For those of you who are new members, this article will explain the Spotter ID's as well as your responsibility as a weather spotter. Some of the following information may have been stated at the seminars; however, I just wanted to take the opportunity to reiterate a few points.

To begin with, what is a spotter ID? Your spotter ID is a number which has been geographically assigned depending upon the location of your residence within the county. The first letter indicates the state while the second two letters represent a county code for the county in which you live. The remaining digits represents a spotter number. If by some chance when you receive your ID and you cannot read it or you believe that your residence has been placed in the wrong county, please contact me immediately at the number listed at the end of this article.

For people who are a part of the amateur radio organization, do not use your spotter ID when relaying a report over the radio network. Only use your ID when actually phoning in a report. Also for anyone who calls in a report please always give your spotter ID. This is helpful to us in pinpointing the damage or location of the storm. However, if you have spotted the severe weather from somewhere other than your residence, please also detail where the severe weather occurred.

Also indicated on the ID card is a listing of severe weather, both winter and summer, which we would like you to report. When relaying this information either by phone or radio, please try to be as concise as possible on the type of damage, hail, and etc. as well as the time which the event occurred.

Finally, remember the toll free severe weather spotter line should only be used to report severe weather information. If you have any questions or are just interested in obtaining weather information, please use the public line (937) 383-0031 rather than the toll free line in those situations.





New Information On the Internet

As many of you have probably realized by now, Wilmington's internet address has changed since the last newsletter. The new address is www.nws.noaa.gov/er/iln. We are sorry for any inconvenience and confusion that this change may have caused.

If you have never visited the web site or have been unable to find it for awhile, you may want to visit it soon. Many new and exciting sections have been added within the past few months.

A few interesting additions include a trivia page, a picture gallery, new links to other web sites, as well as a page of current severe weather information.

The page of current severe weather information includes products such as Storm Predication Center Day 1 and Day 2 severe weather outlooks, information about severe weather which occurred the previous day across the nation, as well as any current watches, warnings or statements. This is a good reference section to discover if severe weather is expected across the area that day or which locations are currently receiving severe weather .

The most exciting new addition, in my mind though, is the Skywarn page. One can find a sundry of information such as the spotter guides, spotter safety, an on-line edition of the Newsletter, as well as the Skywarn training schedule. If there is anything else that you would like to see added to the web page, let me know. My e-mail address is Diane.Innes@noaa.gov. You could also just call with the suggestions at (937) 383-0031 or write at 1901 South SR 134 Wilmington OH 45177, Attn: Diane Innes.





Naming Of The Newsletter

As evident by the title of the newsletter, we have a winner in the contest. Joan Pitula from Cincinnati sent in the entry of Sky Scoop. I hope that everyone approves the new name.

Thank-you to everyone who took the time and effort to send in their entries. I, along with the rest of the selection committee, was amazed by all of the creative names which you entered. It was not an easy selection but the committee jointly agreed that Sky Scoop was both a catchy and appropriate name for the newsletter.

As promised the trophy of the contest was a National Weather Service mug which was recently mailed to Ms. Pitula.





Severe Weather Definition And Safety Tips

With the return of the warm temperatures and mild breezes also returns the threat for severe thunderstorms. Therefore, the following is just a reminder of a few definitions and safety tips.

The official definition of a severe thunderstorm is a thunderstorm which produces winds 58 MPH or higher and/or hail 3/4 of an inch or larger in diameter. A severe thunderstorm watch means conditions are favorable for severe thunderstorms to develop, where as a severe thunderstorm warning means that a severe thunderstorm is occurring or is imminent.

A tornado is a violently rotating column of air which is extended from the cloud base to the ground. When a tornado watch is issued this means that tornadoes may develop in and near the watch area. A tornado warning indicates that a tornado has either been sighted or is indicated by the radar.

A flash flood is a flood which occurs within six hours of a heavy rain event. If a flash flood watch is issued, this means that flash flooding or flooding is possible in the watch area. A flash flood warning means that flash flooding has been reported or is imminent. An urban and small stream flood warning means flooding of small streams, streets, and low-lying areas such as railroad underpasses and urban storm drains is occurring or likely to occur.

The following are a few safety tips if caught in a severe thunderstorm, tornado, or flash flooding situation. In the event of a Severe Thunderstorm: 1) Take shelter in a sturdy shelter and stay away from windows or take shelter inside a hard top car and keep the windows rolled up. 2) Get out of a boat and stay away from water, 3) If caught in the outdoors do not take shelter in small sheds or under isolated trees. Instead crouch in a low spot away from trees, fences or poles, 4) Do not take a bath or shower, and 5) Do not use the phone or other electrical devices. In the event of a Tornado: 1) Go to an interior room or hallway of the lowest floor or basement of a home or building. 2) stay away from windows, 3) If caught outside or in a vehicle, lie flat in a ditch or depression, 4) Abandon a mobile home for a sturdier structure. Finally, during Flash Flooding: 1) evacuate immediately to higher ground if a flood warning is issued or flooding is observed, 2) never drive through a flooded roadway since most flood related deaths occur when people attempt to drive through flood waters., 3) if water is flowing above your ankles, take another route, and 4) never allow children to play around high water, storm drains, or ditches.





First Tornado of the Season

On May 14, 1997 at approximately 500 PM, a mini supercell thunderstorm developed in northern Butler County Ohio. This storm developed along a warm front which was appended to a low in Indiana. Before becoming supercellular, this storm produced large quarter to ping pong size hail (1 inch to 1 1/4 inches in diameter) in Warren and Greene Counties. However, by the time the storm reached north central Clinton county, it had become a supercell and had developed a wall cloud.

In northeastern Clinton County the storm spawned a tornado(s) which initially touched down near Sabina just after 600 PM EDT. The mini supercell thunderstorm continued its treck east across Fayette County, just south of Washington Court House, and along the Pickaway and Ross County borders. The storm finally diminished in northwestern Hocking County approximately 45 miles east and an hour and a half to two hours after the initial tornado touchdown. According to eyewitness reports, the tornado(s) width was about 1/2 mile as it moved from Sabina and into Fayette county. However, as the tornado(s) moved across Ross and Pickaway County, the width decreased to around a 1/4 of a mile.

A team from the Wilmington office conducted both an areal and ground survey on the 15th. After the investigation of the tornado path, the survey team concluded that the tornado(s) touched down and lifted off the ground several times during the one and a half to two hour period.

Some of the more extensive damage caused by the storm included a roof blown off a barn near route 23 in northern Ross county. Damage of this magnitude indicates that the tornado(s) had an intensity of F1 on the Fujita Scale at that time. Estimated wind speeds with an F1 tornado, which is classified as a weak tornado, range between 73 to 112 MPH.