The weekend will be dominated by an upper level trough digging into the Eastern U.S. reaching as far south as the Gulf Coast. The position
of this trough will force a deep south to southwesterly flow across the First Coast. The result:
* periods of rain & storms with pockets of very heavy rain
* a severe threat will develop IF we can get enough sun (heating)
* there will be dry hours, especially Sat.
* warm & very humid
(Radar imagery courtesy our Jax N.W.S.)
Some classic mammatus clouds Fri. afternoon. The pic below is from Tina Jamil on Jax's S'side. The 2nd pic is a beauty from Greg Champman, Orange Park:
Earth Gauge: Lightning Safety Awareness Week – “When Thunder Roars, Go Indoors!”
Summer is the season to be outside. Warm weather compels us to run, swim, hike and ride, and the long hours of sunlight provide ample time to enjoy this most active of seasons. Summer is also prime time for thunderstorms, which produce lightning, among other potentially dangerous hazards. June 23-29, 2013 is Lightning Safety Awareness Week! Lightning occurs in ALL thunderstorms and it is estimated that over 100,000 thunderstorms occur each year in the United States.
Viewer Tip: Florida sees an average of 60 to 100 thunderstorm days per year. In 2012, lightning accounted for 28 deaths in the U.S., down from the 30-year average of 55. That number can be reduced even more by knowing how to avoid lightning and what to do if you are stuck outside during a thunderstorm. These helpful hints will help you stay safe:
• Pay attention to the forecast. When thunderstorm development is expected, meteorologists often issue a statement early in the day about when the chance for thunderstorms is highest. If your area has a high potential for thunderstorms, make plans to be inside during that time. Lightning can strike up to 10 miles away from a thunderstorm. If a severe thunderstorm watch or warning has been issued for your area, take cover immediately and wait for at least 30 minutes after the storm has passed to head back outside.
• If you must be outdoors, avoid activities that increase the risk of being struck by lightning, such as mountaintop hiking, swimming at beaches and outdoor pools, golfing and playing other sports in open fields.
• If you are caught outside during a thunderstorm and cannot reach a safe, indoor location, avoid open fields and the tops of hills or ridge tops. Stay away from tall, isolated trees and other tall objects. If you’re in a forest, stay near a lower stand of trees. Stay away from water, wet items and metal objects like fences and poles.
• Learn more about lightning development, safety, and science at NOAA’s Lightning Safety webpage.
Did you know?
• Lightning impacts the environment: Every year, lightning causes forest, grass and house fires across the United States. According to the National Fire Protection Association, lightning caused an average of 24,600 fires resulting in 407 million dollars in damages annually from 2004-2008. Wildfires started by lightning burn on average 5.5 million acres each year.
• The environment impacts thunderstorm development: Many big cities experience the urban heat island effect. Urban heat islands form when buildings, roads and other infrastructure absorb heat, making cities warmer than surrounding rural areas. In Atlanta, studies have shown that excess heat from the urban heat island plays a role in producing increased rainfall and thunderstorms over the city. Similarly, Houston (dubbed the “Lightning Capital of Texas”) received more lightning than surrounding less-developed areas over a 12-year period. Data analysis suggests that Houston’s urban heat island effect causes clouds and thunderstorms. Air pollution in Houston may also play a role – small particles emitted by cars and power plants join up with other aerosols to form nuclei on which water condenses to form clouds.
Thanks to Mount Washington Observatory for providing some of these lightning facts.
(Sources: NOAA, “Lightning Safety: When Thunder Roars, Go Indoors!”; EPA, “Heat Island Effect,”; NASA, “Welcome to the Thunder Dome Atlanta’s Urban Heat Island Alters Weather Patterns,”; NASA, “Houston Called ‘Lightning Capital of Texas,’”; NOAA, “Thunderstorms, Tornadoes, Lightning…Nature’s Most Violent Storms,”; NWS, “Natural Hazard Statistics,”; National Fire Protection Association, “Lightning Fires and Lightning Strikes,”; NOAA, “Number of Cloud-to-Ground Flashes by State from 1997-2011,”)
State of the Climate Report - Highlights from NOAA’s National Climatic Data Center. Visit here for more information.
Climate Fact: May Was Exceptionally Cold and Wet in the Southeast
Average May temperatures across the Southeast were well below normal – sometimes two to three degrees Fahrenheit below average in areas across Alabama, Georgia, South Carolina and northeastern Florida. All told, 300 daily minimum temperature records and more than 250 daily low maximum temperature records were tied or broken across the Southeast in May. The Southeast’s northern coastline and eastern portions of North Carolina and Virginia were the only places where monthly average temperatures were above normal (predominantly one to two degrees Fahrenheit higher than usual). However, cold temperatures were only half the story. The Southeast was doused with precipitation by slow-moving systems and intense thunderstorms in May, especially in Florida, northern sections of Alabama, Georgia, South Carolina and western portions of North Carolina. These storms dropped as much as nine inches at a time throughout the better part of May, yielding staggering monthly precipitation totals in places like West Palm Beach, FL and Miami, FL, where 15.67 and 11 inches fell, respectively. Over the course of a week, five inches of rain per day fell across northern Alabama, Georgia and western North Carolina, and rainfall rates of two inches per hour were reported in the Keys weeks later. Many of these storms were severe: 194 reports of severe weather were received on 19 days in May that spawned four EF-0 tornadoes. These rains eliminated the last of South Carolina’s drought for the first time since April 2010, but drought conditions still persist in a few isolated pockets around extreme northwestern Florida and southern Alabama. Eastern North Carolina also remains in an abnormally dry state.
Have a great & safe weekend!