The following description has been extracted from a NOAA/NWS newsletter - The Champlain Weather Chronicle, Vol. 1, No. 1, September.
In what could be considered a quiet summer given the fact most areas received below normal rainfall, some rather interesting weather did occur. One of the first items that comes to mind is the above normal temperatures, especially in July. There were 18 days in which the temperature reached or exceeded 90 degrees. In addition, the 10 times it hit at least 90 in July makes it the leading July month for the most number of times the temperature reached 90 degrees or more. The July months of 1911, 1955, and 1975 all reported 9 days of 90+ temperatures.
The average number of days a year in which the temperature reaches 90 degrees or more in Burlington is 6, so 1999 had three times as many 90+ degree days. If we look back just one year to the summer of 1998, the temperature never reached 90 degrees in the months of May, June, July, August and September.
July 6th proved to be the most widespread severe weather event of the season. A cold front moved east across the eastern Great Lakes and into the area during the afternoon hours. Temperatures in advance of the front climbed into the lower 90s with dew points ranging from the mid 60s to the lower 70s. This helped to create an increasingly unstable atmosphere. The cold front provided a source of lift to this environment and helped to develop the thunderstorms. The wind fields aloft and an upper level trough of low pressure moving toward the area allowed the thunderstorms to become severe.
By early afternoon, thunderstorms developed over northern New York and formed into a large line. The storms became severe across portions of Clinton and Essex counties and toppled trees. Once the line moved into Vermont, nearly every county reported trees and power lines down. Rutland and Windsor counties were especially hard hit. Fifteen severe thunderstorm warnings were issued during this event. The warnings were the final stage of the Outlook, Watch, Warning process that helps prepare the people of northern New York and northen and central Vermont for hazardous weather. For a view of the radar on the 6th of July, visit the internet version of the CWC.
A rather localized thunderstorm event made some headlines across the Champlain Valley in early September. The night of September 8th, a thunderstorm with very heavy rain moved across portions of Chittenden County. This storm hit the Burlington International Airport (BIA) and was quickly followed by another thunderstorm. This second storm was the result of the two thunderstorms merging together. This tends to enhance the strength of a thunderstorm. As a result, from 7:00 pm to 8:00 pm 2.17 inches of rain fell at the BIA. This broke the record for most rainfall in a one hour time period which was 2.16 inches set back on May 23rd 1955. Also, the rainfall from 6:00 pm to 8:00 pm measured 2.24 inches which set a record for the most rain in two hour period. The previous record was 2.23 inches.
The summer of 1999 has been a dry one for the north country. Dry conditions actually began toward the end of 1998. Interestingly enough, 1998 was a record wet year for Burlington, VT even though December of 1998 was the 3rd driest December ever. January 1999 saw above normal precipitation, but from that point on most of the area received less than normal amounts. Rainfall for the summer months of June, July and August have been below normal across the region.
Essex County, New York was particularly hard hit, and was the first county in Burlingtons area of responsibility to be declared an agricultural disaster area by the state of New York. (See the interactive version of the CWC for more information or visit the following web address: The end of the summer would see all of Vermont declared an agricultural disaster area as well.
Area farmers were affected the most. They had difficulty getting their 3rd cutting of hay in, and feed corn crops were smaller as well. As a result, some dairy farms in the region will likely be buying feed to make up the shortfall for the long winter ahead.
Water supply became an issue by the end of the summer. In Essex County NY, Bartlett Pond dropped to very low levels, threatening the town of Moriahs water supply. There were many reports of small hand dug water wells and natural springs going dry, but for the most part municipal water supplies were able to handle the demand.
In areas where wells went dry, hailing water became the only option. This became a larger issue again from farmers, who had to haul potable water for their personal use and for milking as well as water for their cattle.
Conditions even became dry enough in Essex County NY to allow forest fires to burn for a few days near Elizabethtown and Keene Valley.
One of the measurements used to quantify the severity of a drought is the Palmer Drought Index (PDI). As of early September, Palmer Drought Index values across the area were as follows:
In Northern New York...
|St. Lawrence Valley -2.0
|Northern Adirondacks -4.3
|NY Champlain Valley -5.1
|Green Mountains -2.4
|VT Champlain Valley -4.7
|Southern Vermont -2.6
The PDI can be found at http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_montoring/palmer.gif
The drought also affected area rivers, which were well below normal during the entire summer. Streamflow is monitored by the U.S. Geologic Survey, and can be viewed for Vermont at: http://water.usgs.gov/cgi-bin/aily_flow?vt and for New York state at: http://water.usgs.gov/cgi-bin/daily_flow?ny