Weather (Atlanta): Difference between revisions

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=== Summer ===
=== Summer ===
Summer means light breezes in Atlanta. With no close by ocean for a sea breeze and the jet stream vacationing for the most part in Canada, there are few means available create consistent windy weather. Put another way, when it's 95 degrees in Idaho, Atlanta and Florida all at the same time, it's difficult to create wind by cold air replacing warm, rising air.
The most prevalent ways for temperature induced wind in the summer is a) thunderstorms and b) tropical systems. Once in a long while, you may get a decent breeze drawn by a far away thunderstorm. Remember a couple of things, however:
* lightning can strike up to ten miles from a cloud and there are few things more frightening than holding a 490cm lightning rod in your hands while being the tallest object for hundreds of yards
* the wind can shut down at the most inconvenient of times, leaving you in the middle of the lake in the pouring rain
If you have a smart phone with a good radar app, you can keep an eye on how far a system is from you if you get so lucky. However, we urge you to err on the side of caution. You don't want to have one of those "what was I thinking" moments. (We speak from experience.)
Tropical systems (better known as Hurricane Season) can bring strong breezes between June and November. Timing and location are critical as often these systems are fast moving and conditions can vary greatly depending upon how far you are from the center of the system. Winds flow in to a tropical system (cyclonic) counter clockwise. If you are north and east of the approaching system, the winds will be from the NE to E while if you are west, the winds will be more N to NW. As the center passes, you can get as much as a 180 degree wind shift. The closer you are to the center, the more pronounced the shift. The shifts will clock to the right (clockwise). You may start the day with a NE breeze and then have it go E and finally SE.
Tropical systems, of course, behave erratically. You may well go to the lake expecting a breeze but find nothing as the storm has shifted 50 miles to the east.
== Further Reading ==
* Great elementary explanation of weather systems: [http://www.fas.org/irp/imint/docs/rst/Sect14/Sect14_1c.html Federation of American Scientists]




[[Category:Weather]]
[[Category:Weather]]

Revision as of 11:33, 10 November 2011

While every place has weather, Atlanta and the inland Southeast have certain weather characteristics that a windsurfer should know about.

General

Atlanta, while a pleasant place to live and work, is not a place renown for its wind. A cynic once said of Atlanta, "it's where wind goes when it dies."

The winds we do get are driven primarily by two processes: the jet stream and tropical events such as depressions and storms. Generally, wind is created by either the earth's rotation (trade winds) or differences in air temperature (cold fronts, tropical storms, sea breezes). Because of our location in the Southeast United States, a fair amount of open, surrounding land and irregular geography, especially to the west, and distance from the ocean means that a lot of the factors that make other locations (beaches, tropics, Columbia Gorge) windy simply don't exist here. Many localized weather patterns stem from differences in temperature between land and adjacent bodies of water.

That doesn't mean its all bad. It just means that

  • windsurfers tend to become students of weather
  • windsurfers tend also to have other forms of outdoor recreation, e.g. cycling, kayaking, wake boarding, motor and dirt biking
  • windsurfers tend to make pilgrimages to windier locations such as the Outer Banks, Florida, the Gorge, etc.

Once you learn and understand what conditions make wind more likely here, you'll be happier and have more effective time on the water.

Prevailing Winds

The prevailing and upper level winds at Atlanta's latitude are from the west. Weather systems will tend to move from west to east. Even tropical storms at our latitude are heavily influenced by this so tend to "bend right" as they move northward.

Locally, this has a significant impact on days with east wind.

The Jet Stream

Excluding tropical systems, almost all weather systems here are driven by the jet stream. When the jet moves southwards in the fall and winter, we tend to have the common cycle of weather fronts. In the summer, the jet retires northwards and the air becomes very stable in the Southeast, which means light and variable winds. The jet will sometimes venture south in the summer and brings relief in temperatures, but this is uncommon.


Tropical Events and Weather

We can have tropical events - depressions, storms and even hurricanes - during the season that goes from June until the end of November. The wind strength and direction will depend greatly on the proximity of the center of circulation and on which side it passes us. While such winds do provide us with great fun, we are cognizant that the same system may well have wreaked havoc elsewhere.

Seasons

Fall

During autumn, cold, dry air moving south from northern Canada converges with warm, moist air moving north from the Gulf of Mexico, forming large storm systems in the middle of the North American continent. http://en.wikipedia.org/wiki/Great_Lakes_Storm_of_1913

Winter

Spring

Summer

Summer means light breezes in Atlanta. With no close by ocean for a sea breeze and the jet stream vacationing for the most part in Canada, there are few means available create consistent windy weather. Put another way, when it's 95 degrees in Idaho, Atlanta and Florida all at the same time, it's difficult to create wind by cold air replacing warm, rising air.

The most prevalent ways for temperature induced wind in the summer is a) thunderstorms and b) tropical systems. Once in a long while, you may get a decent breeze drawn by a far away thunderstorm. Remember a couple of things, however:

  • lightning can strike up to ten miles from a cloud and there are few things more frightening than holding a 490cm lightning rod in your hands while being the tallest object for hundreds of yards
  • the wind can shut down at the most inconvenient of times, leaving you in the middle of the lake in the pouring rain

If you have a smart phone with a good radar app, you can keep an eye on how far a system is from you if you get so lucky. However, we urge you to err on the side of caution. You don't want to have one of those "what was I thinking" moments. (We speak from experience.)

Tropical systems (better known as Hurricane Season) can bring strong breezes between June and November. Timing and location are critical as often these systems are fast moving and conditions can vary greatly depending upon how far you are from the center of the system. Winds flow in to a tropical system (cyclonic) counter clockwise. If you are north and east of the approaching system, the winds will be from the NE to E while if you are west, the winds will be more N to NW. As the center passes, you can get as much as a 180 degree wind shift. The closer you are to the center, the more pronounced the shift. The shifts will clock to the right (clockwise). You may start the day with a NE breeze and then have it go E and finally SE.

Tropical systems, of course, behave erratically. You may well go to the lake expecting a breeze but find nothing as the storm has shifted 50 miles to the east.


Further Reading