Summer Storms Part II ~ WEATHER 101 with Al Kaprielian
By: Al Kaprielian – August, 2016
Summer weather finally arrived in July. A heat wave occurred with three or more consecutive days of 90 degrees or higher. July is the hottest month of the year. The reason for the heat was an intense Bermuda (subtropical) high pressure system in the Atlantic Ocean.
This strong HIGH PRESSHA! pushed the jet stream to our north into Canada. This put our region on the south side of the jet stream which is the hotter side. With the heat and humidity came some severe thunderstorms during the month of July.
Severe thunderstorms produce strong damaging wind gusts that cause trees to fall on power lines causing power outages. This occurred in the month of July. Severe thunderstorms can also produce frequent and dangerous lightening. Also hail is possible with severe thunderstorms. During one of the severe thunderstorms in July a microburst occurred in Plaistow New Hampshire with 80-90 mile per hour wind gusts. This caused many downed trees and power outages. A microburst is not a tornado. The reason is that the trees that fall are in straight lines. They are not down in a circular direction.
When trees are down in a circular direction this is reported as a tornado. Remember a tornado is a funnel cloud that touches the ground. Not all funnel clouds that form touch the ground, these stay aloft and are not tornadoes. When trees fall due to severe thunderstorms the damage has to be accessed by employees of the National weather service to see if a tornado occurred or a microburst. Strong winds aloft mix down to the earth’s surface and this can cause a microburst to form. A tornado or microburst can not be conveyed to the public until the National Weather Service surveys the damage. A funnel cloud or more than one funnel cloud can form with severe thunderstorms; although some severe thunderstorms may not produce tornadoes.
Remember when rotation occurs aloft in the Cumulonimbus clouds, this can be seen by Meteorologists on Radar. This rotation may be the start of the formation of a funnel cloud. During severe weather remember to get inside and away from the windows. The safest place is on the lowest floor, especially a basement.
When a tornado occurs, the rotation as the funnel cloud touches the ground. It picks up any debris on the ground and causes extensive damage. Homes are destroyed by tornadoes. There is total destruction in the path the tornado takes. Tornadoes result from severe thunderstorms.
Severe thunderstorms occur in a hot and humid environment. They are enhanced by a trigger, like a cold front, or a potent upper level disturbance. A tornado watch is issued when severe thunderstorms occur. If a funnel cloud touches the ground then a tornado warning is issued.
What can we expect during the month of August? Yes, more heat and humidity. As the month moves on, the increase in hurricane formation occurs over the Gulf of Mexico and Atlantic Ocean. A reason is that the ocean water temperatures start increasing in August.
Peak hurricane season is in mid August to mid September. The reason is that this time period is when the ocean waters are the warmest. Time will tell how active this year’s hurricane season will be. We sure could use the rainfall from a hurricane as areas north & west of Boston including Southern New Hampshire are in a severe drought. Many inches of rain are needed to eliminate this drought. Of course hurricanes produce strong winds and wind damage so we do not want to see this happen.
However the rain for a hurricane or tropical system will surely be appreciated. Now that areas are in a severe drought, please be careful with lighting materials. Be especially careful when barbequing. Also check with your local fire officials before doing any open burning of brush. With dry conditions and if there are gusty winds any wildfires that begin can spread rapidly and become out of control. As we move through the month of August, length of day sadly continues to decrease. This will eventually start to bring cooler days more typical of fall.
This can occur during some days in the month of August.
When tropical systems develop in August and September remember to listen to weather forecasts each day to see how these systems will intensify and track. With tropical systems we have to be ready and have to stay abrupt to weather forecasts each day. If a tropical system develops in the Gulf of Mexico or off of Florida, stay informed to weather forecasts each day to see where these tropical systems will track. During August, with more heat & humidity, remember to drink plenty of water and stay hydrated. Refrain from strenuous outdoor activities during the heat of day. Perform these activities early in the day or in the evening after the sun goes down. During August continue to listen to weather forecasts each day; computer models can change from day to day. Next month we will talk about hurricanes and see how this season is evolving. Stay cool and continue to enjoy summer!!
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