HURRICANE LENNY HITS ST. CROIX

BY

JAMES A. PETRAIT

Hurricane Lenny was felt mainly during the afternoon of November 17, 1999 on St. Croix, VI. At a location near the Frederiksted part of the island at 17 deg. 43 min. N. Latitude and 64 deg. 53 min. West Longitude. Winds were estimated to be around 100 mph (according to radio reports) and were continuous for several hours and gusts continued for a day or 2 later. The wind direction was mainly from the north to east and did not reverse. The eye of the hurricane did not pass through here. The wind did not blow all of the vegetation from the trees and create a snowstorm-like look with flying debris as was the case with Hurricane Georges. However the gusts seemed to be selective depending on the terrain and did take the roof off a small shed in this area and blew some branches, signs, fences, and wires down. However other parts of the islands experienced greater difficulties and those near the shores were especially vulnerable.

According to the records. this was the first time that a Category 5 hurricane went from west to east so late in the hurricane season. Also the barometric pressure has been unusually low in this area for several weeks and continuous to be lower than normal on November 27 with a 1200 AST reading of 29.85 inches. Teachers and students should feel free to make use of the data to make graphs and as part of a study of an abiotic factor.

Below is the data which can be used as part of your lesson plan. I would suggest that you have the students make a graph from the data and then have them interpret the graph. Be aware that the times in the tables need to be converted to elapsed time in minutes to make a more accurate graph (to compensate for time measurements not being in the decimal system). I will post the graph from the first school to send me an accurate and complete line graph of all of the data points in the table. This should be in the form of a .jpg or .gif file of 300 kilobytes or less. Send an interpretation file with it in the email to which the file is attached.

BAROMETRIC PRESSURE CHANGES DURING HURRICANE LENNY ON ST.CROIX
TIME IS AST BAROMETRIC PRESSURE (BP) IS IN INCHES DATE IS 11/17/99

LOCATION: ST. JOSEPH HIGH SCHOOL, FREDERIKSTED, VI 00840
17 DEG. 43 MIN. NORTH LATITUDE, 64 DEG. 53 MIN. WEST LONGITUDE
OBSERVER: JAMES A. PETRAIT

             TIME      BP            TIME      BP            TIME      BP            TIME      BP
             0000     29.59           1200     29.32           1530     28.97           1900      29.29
             0100     29.56           1230     29.26           1600     28.97           1930      29.32
             0400     29.53           1300     29.21           1630     29.06           2000      29.35
             0600     29.47           1330     29.12           1700     29.09           2400      29.38
             0800     29.50           1400     29.03           1730     29.18
             1000     29.47           1430     29.00           1800     29.21
             1100     29.41           1500     29.00           1830     29.26

ADDITIONAL REFERENCE POINTS:
ON 11/16/99 AT 1200 THE BP WAS 29.65
ON 11/18/99 AT 0700 THE BP WAS 29.50
ON11/18/99 AT 1900 THE BP WAS 29.62
NORMALLY THE BP STAYS AROUND 30.00

Check out all of the other classroom projects that are listed at the Gateway of THE CYBERUNIVERSE WEBSITES SYSTEM OF JAMES A. PETRAIT. The data for Hurricane Georges is still listed and students may still submit graphs for the barometric data from that event. Then they can compare the graphs for the 2 hurricanes. For other aspects of the hurricane, look in the bookmarks file of the website for the St. Croix Source online newspaper or click on the Weather Underground graphic.

Permission is granted to make multiple copies of this page for non-profit educational use. Be sure to give the author credit.

From here you can go back to ST. JOSEPH HIGH SCHOOL NEWS FROM THE 1999-2000 SCHOOL YEAR