3 Ocak 2013 Perşembe




Alabama State Climate

Climate Map
Alabama has a temperate climate marked by very hot, humid summers and mild winters. Precipitation occurs throughout the year, and the state is among the four wettest in the United States, averaging 58 inches (1,444 mm) of rain annually. The average annual temperature, 63°F (16°C), is among the warmest in the country and allows for a growing season that exceeds 300 days per year.
Because it neighbors the Gulf of Mexico, Alabama receives many tropical storms and occasional hurricanes, which generate tremendous amounts of rain as they move inland. The Gulf’s hot, moist air also gives Alabama the nation’s greatest occurrence of thunderstorms, with the Mobile area reporting thunder activity between 70 and 80 days per year. Even inland, toward the Appalachian Mountains, thunderstorms are reported about 60 days per year. Hail can occur during thunderstorms, but lightning from them is a bigger danger. Although Alabama is located well away from "Tornado Alley" in the center of the U.S., the state is categorized, along with Mississippi and other neighboring states, as part of "Dixie Alley," a corridor noted for its own special vulnerability to violent tornadoes. Alabama is as severely afflicted with tornadoes as famously tornado-prone Kansas.

Balmy Gulf Coast
Winters are mild throughout the state, with rare freezes and light snowfall that does not linger. Conditions along the Gulf Coast are balmy compared to northern states, and for that reason the region receives a large amount of tourist traffic during this season. Mobile’s high January temperature can climb to 61°F (16°C), while the lowest monthly temperatures in the state drop to just below freezing at 31°F (0.6°C).
Spring starts early in Alabama, in March, with high temperatures in the cities rising into the mid 60s and low 70s F (18° to 22°C) and low temperatures in the 40s F (4.4° to 9.4°C). By April, temperatures are in the 70s F (21° to 26°C). Spring is also the time of greatest danger from tornadoes, tropical storms, and hurricanes. By May, city temperatures have climbed into the low to mid 80s F (27° to 30°C).
Summer is hot and humid—the classic sultry, muggy weather in literature about the South. High temperatures throughout the state average more than 90°F (32°C), although some areas of the northern highlands are slightly cooler. Rainfall is frequent, so summer days can be marked by periods of partial or complete cloudiness. Fall is mild, the cooler days creating conditions for colorful fall foliage. High temperatures in October are in the mid to high 70s F (21° to 26°C), then drop off by November to the mid to high 60s F (18° to 20°C). Rain is normal during the season. One peculiarity about fall in Alabama is that it is the state’s second tornado season, an unusual circumstance among places where tornadoes are common.

Rare Overnight Freezing Temperatures
Alabama’s all-time high temperature of 112°F  (44°C) was recorded on September 5, 1925, at Centerville, southwest of Birmingham in the state’s center. The all-time low temperature of -27°F (-33°C) was recorded on January 30, 1966, at New Market, a town in the state’s extreme northeast near Huntsville. The range between its highest and lowest recorded temperatures is 139°F (59°C), a figure that puts Alabama among the 10 states with the smallest range of extremes.
Low temperatures in January are around 40°F (4°C) in Mobile and 32°F (0°C) in Birmingham. The average high temperature in July, the hottest month, is 91°F (33°C) in both cities.
Precipitation Map
Among the four largest cities in this fourth wettest state—Birmingham, Huntsville, Mobile, and Montgomery—Mobile receives the highest amount of rain, 66 inches (1,684 mm). The driest among the four, Birmingham, receives 54 inches (1,371 mm). Each city has about 120 days of precipitation per year.
The state’s wettest location is Robertsdale, in the south, at 67 inches (1,702 mm) per year. The driest location is near Montgomery, in the state’s center, at 48 inches (1,219 mm) per year.
While snow is not rare, it is extremely light. For example, among the state’s major cities, Birmingham receives 1.9 inches (48.3 mm) of snow per year, while Huntsville receives 1.5 inches (38.1 mm). Mobile, on the Gulf Coast, rarely receives snow and can go a dozen years without seeing any. 
The northwestern town of Florence holds the state record for one-day and one-season snowfall: 19.2 inches (488 mm) and 27.9 inches (709 mm), respectively.
Mobile is the state’s most humid city, but not by much. Its average morning humidity of 86 percent compares almost exactly to Montgomery’s 86 percent, Huntsville’s 85 percent, and Birmingham’s 84 percent. The afternoon percentage readings for those cities are, respectively, 65 percent, 59 percent, 61 percent, and 59 percent. In August, humidity in Huntsville, Mobile, and Montgomery reaches 90 percent.

Dark, Humid Skies Over Mobile
While those average annual humidity readings compare almost exactly with other Southern cities, such as Pensacola, Florida, and Knoxville, Tennessee, they also compare to the daily average for San Francisco. However, the latter city’s mild year-round temperatures keep its relatively high humidity comfortable.
The state’s wet climate means that about 260 days out of the year are cloudy or partly cloudy. Among the state’s four largest cities, Montgomery enjoys the highest number of clear days per year at 107. But that figure is only slightly higher than the ones for Mobile (102 days), Huntsville (100 days), and Birmingham (99 days).    
Huntsville is the cloudiest of the four cities, with 164 completely overcast days per year. Mobile has the least number, 147, which is still 44 percent more than the number of clear days the city enjoys per year.

Flooding Occurs in Low Lying Areas
Although the state has three distinct geographic regions—the northern highlands, the Piedmont section that dominates Alabama’s heartland, and the coastal Gulf region of the southwest—the climate across the state is generally uniform. Rainfall and temperatures decrease as one moves north, but not significantly. Each region is vulnerable to occasional flooding from strong tropical storms. The northern part of the state is more vulnerable to tornadoes and receives the bigger portion of whatever snow falls.

Tornado Strike in Carbon Hill, Alabama
From 1961 through 2009, the Federal Emergency Management Agency made 51 Major Disaster Declarations for Alabama that included the effects, often combined, of tropical and severe storms (32), flooding (31), tornadoes (22), and hurricanes (11).
Alabama ranks with Kansas as the state that has reported more F5 tornadoes than any other. An F5 tornado on the Fujita Scale is described as an "incredible tornado," with wind speeds of 261 to 318 mph (423 to 515 kph). Those powerful storms have made the state the site of more tornado fatalities than any other state except for Texas and Mississippi.
There are two tornado seasons, spring and late fall. Having a second season of severe risk is an unusual state of affairs, since most regions that experience tornadoes have their heaviest occurrences in one particular part of the year.
Hurricanes are not rare in Alabama, but the state historically has not experienced the level of devastation that has made Florida, Louisiana, or Mississippi stand out in people’s minds. The two greatest hurricanes of the modern era have been Camille, in 1969, and Katrina, in 2005. Hurricanes often spawn tornadoes, severe storms, and thunderstorms, which in turn can cause great damage. 

Hurricane Katrina Damage
Because the state receives so much rainfall, there is at least one moderate flood per year on one of its major rivers. In the modern era, there have been three great floods, two of them within the past generation: the Great Flood of March 1929; the flood of March 1990; and the July 1994 flood caused by the stalled tropical storm Alberto. Low coastal areas have begun to experience greater vulnerability to flooding because of increased commercial and residential development.
The state has experienced six major droughts since the 1920s, with the drought of 1950–63 considered the most severe on record. The drought of 1984–88 was almost as severe. Cumulative rainfall deficits over the course of the drought amounted to more than 50 inches (1,270 mm) in some areas, the equivalent of one year’s worth of rainfall.
Lightning from the state’s abundant thunderstorms make it rank seventh nationally in the annual number of deaths from lightning and ninth in the number of deaths from lightning strikes per capita. Thunderstorms in the central and northern parts of the state occasionally produce large hail, but damage and injuries from this form of precipitation are slight and rare. 
  • Alabama’s range of hot and cold temperatures, 139°F, ranks 44th among the states. Only Hawaii (88°F), Florida (111°F), Georgia (129°), South Carolina (130°), and Louisiana (130°) have narrower temperature extreme ranges.
  • Birmingham ranks 10th on the list of U.S. cities most prone to tornadoes.
  • Montgomery ranks ninth among U.S. cities as the most uncomfortable place to be in summer because of its high heat and humidity.
  • Mobile is the fifth rainiest city in the country at 66 inches (1,676 mm) per year. The city also ranks sixth nationally as the city most prone to thunderstorms.
-World Trade Press

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