The winter weather forecasts for 2009-2010 have arrived, and there appears to be a lot of agreement between the three I have reviewed so far. This winter (December through February) is likely to be affected by an El Nino episode that alters the jetstream patterns, especially the southern branch, bringing a colder, wetter winter for most of the southeast and mid-Atlantic States.

The Weather Service predicts a better than 40% chance of cooler than normal weather in Virginia, North Carolina and Georgia, and the southern half of Alabama, Mississippi and Louisiana. Kentucky, Tennessee, and the northern half of the deep South are also likely to be cooler than normal. Much warmer than normal conditions are expected in the northern Great Plains and Rocky Mountain states, with warmer than normal conditions in Wisconsin, and stretching south into Nebraska and New Mexico.

The Accuweather winter forecast restricts the much below normal temperatures to Tennessee, Alabama and Mississippi, along with northern Georgia, western Virginia, and the western Carolinas. They predict above or below normal temperatures for the entire country, with no area set for normal temperatures.

The Weather Service precipitation outlook calls for a much greater chance of rain in Florida south of Orlando and in south Texas, with above normal precipitation in southern Georgia, most of Texas, and in California. Drier than normal weather is expected in the mid-Mississippi valley and in the northwest. The rest of the country has equal chances of above or below normal precipitation.

The Accuweather forecast brings the above-normal precipitation chances further north, covering the Carolinas, Georgia, Alabama, Mississippi, and west to New Mexico, and north into California. Dry conditions are expected in the midwest and upper Northwest.

All of this means that the metro Atlanta area has a better than normal chance of seeing snow or ice this winter, especially when compared to the last few years. And that is what WSB Radio meteorologist Kirk Melhuish says in his preliminary winter outlook. Melhuish predicts normal temperatures and above normal precipitation in the Atlanta area, with an above normal chance of ice and snow. He will issue a final outlook around Thanksgiving.

July ended up being cooler than normal for the northern and eastern parts of the US, in some cases setting records or near records for the cold weather.

In Atlanta, the average temperature of 78.1 was 1.9 degrees cooler than normal, and cooler than it was in June, when the average temperature was 79.8 degrees, or three degrees above normal. July’s colder than normal temperatures were helped out by low humidity and much colder than normal lows from the 18th through the 21st, with two record low temperatures set during that time.

Atlanta was not the only location to have a colder than normal July. In New York City, the average temperature of 72.7 was 3.8 degrees below normal, continuing a trend that began earlier in the spring. With a high temperature of 84 degrees in June and 86 in July, this was the second time New York weather failed to reach 90 degrees in June or July. The other time was in 1996.

Other cities with colder than normal temperatures in July include Chicago, whose average temperature of 71.0 degrees was 4.5 degrees colder than normal; Cincinnati, with a 70.9, 5.9 degrees colder than normal and Kansas City, Missouri, with an average of 75.4, 3.1 degrees colder than normal.

The heat did show up in much of Texas. In Houston, the average temperature of 86.7 was 3.1 degrees warmer then normal, and in Austin, the average of 89 was 4.8 degrees warmer than normal.

Rainfall in Georgia seemed to be concentrated in the western part of the state. Atlanta ended up with 5.02 inches of July rain, just slightly less than normal. However in Lawrenceville, I only received 3.48 inches, most of it on the last few days of the month. In Athens, only 1.33 inches of precipitation fell, which was 30% of normal July rainfall.

The other thing that was missing in July was any sign of tropical weather activity. No storms were observed in either June or July in the Atlantic basin, and the team over at Colorado State University has lowered its predictions for the season to ten named storms from the eleven forecast back in early June, and four hurricanes, down from five predicted earlier.

The comparatively light hurricane forecast is due to the development of El Nino conditions in the Pacific ocean. The warmer than normal ocean temperatures tend to produce greater than normal upper level winds, which prevent storm from forming as easily.

The busiest period for tropical storms and hurricanes is typically from mid-August to late September, so we still have to face the heart of the season. And, remember than even though there are fewer than normal storms, the few storms than do occur can still be major–remember Andrew in 1992. It was the first named storm of the season, and devastated Miami and southern Florida.

Widespread March rainfall has caused all but a few North Georgia counties to become drought free. According to information from Georgia Climatologist David Stooksbury, the only counties still considered to be in moderate drought are Union, Towns, Rabun, Lumpkin, White, Habersham, Hall and Stephens. A few northwest Georgia counties are drought free, while the remainder, including Gwinnett, are classified as abnormally dry, mostly due to the long-term rain deficit we’ve experienced for the past four years.

Atlanta has recorded 7.12 inches of rain in March, over two inches more than normal. For the year, the deficit is 1.09 inches. With 7.03 inches of March rain in Athens, the Classic City is only .39 inches below normal for the year. With an additional inch or so expected Tuesday through Thursday, both cities could be back to normal rainfall by the end of the week.

While the plentiful precipitation seems to have encouraged Atlanta area flora to show their spring colors more strongly than in recent years, the hidden subtext of the drought picture, which I assume will be reflected in Thursday’s drought monitor, is that the counties that make up Lake Lanier’s drainage basin, including Hall and Habersham, are still in a moderate drought. Last week’s rainfall raised Lanier’s level by over a foot, but the lake is still ten feet below full summer pool.

The current climate pattern of a weak La Nina transitioning to neutral is responsible for much of the changes to a wetter spring. According to Stooksbury:

Currently the climate pattern is a weak La Niña pattern tending toward a neutral pattern. A typical weak La Niña spring brings wet weather across the northern piedmont into the mountains, just like north Georgia experienced in March.

Moisture conditions are in good shape across most of the state’s northern half, but the typical moisture recharge period will be ending soon. By the middle of April, plants are in full spring growth and using tremendous amounts of water.

By the middle of April we can expect the soils to begin to dry because of increased plant water use. Additionally, by the middle of April, temperatures are routinely in the 70s to low 80s. This means that evaporation will increase. This late spring and summer drying is normal.

The outlook is for a few more weeks of recharge followed by the normal drying of the soils due to plant water use and evaporation. May is usually a dry month. Little recharge is expected from May through October, but this is typical for Georgia.

The big unknown is what the tropics will bring Georgia this summer and winter. Much of the state’s late summer and fall rain comes from tropical disturbances. Without moisture from the tropics, August through October can be very dry. At this time there are no clear indications of how much rainfall the summer will bring.

The Weather Service has issued its outlook for spring weather – April, May and June – although some would argue that especially in the South, spring runs from March through May. In any case, the next three months don’t show a trend one way or another for most of the Southeast US.

East of the Mississippi River, there are equal chances of above or below normal temperatures. There’s a good chance of warmer than normal weather in the southwest, especially in Texas and New Mexico. The Northwest is expected to be cooler than normal, especially in Washington. Hawaii and parts of Alaska should be cooler than normal as well.

Likely wetter than normal weather is expected in Alaska and Hawaii, while there should be less than normal precipitation in south Florida, the Rocky Mountains and the Pacific Northwest. The rest of the country has equal chances of above or below normal rainfall.

Because of all the snow this winter, there is a greater than normal chance of flooding in the upper Midwest, especially along the Red River Valley. There’s also a better than normal chance of flooding along the western Great Lakes region of Michigan and northern Illinois, Indiana and Ohio.

The overall weather is considered to be in an El Nino pattern, the warm cycle of Pacific Ocean sea surface temperatures. The El Nino pattern is expected to diminish to a neutral pattern later this spring, and in any case, its effects are less pronounced in the spring and summer months. In the southeast, where El Nino tends to bring drier than normal weather, you can see this in the outlook for April, which is likely to be drier then normal, compared to the April-June outlook, which could see above, normal or below normal rainfall.

In the short term, north Georgia could see a rainy stretch starting midweek, followed by a chance of freezing temperatures at night following more rain and the passage of a cold front next weekend. Until then, however, we’ll have pleasant late March weather, so get out and enjoy it.

I was winding my way through the big box home center today picking up a few things, when I noticed the racks of petunias, geraniums and even tomatoes in gallon containers waiting to be sold to unsuspecting consumers.

We’re about to see a real warm up starting on Thursday. By the weekend, we’re likely to see high temperatures in the mid-70s, with lows around 50, which will continue through the middle of next week. Undoubtedly, these tender annuals will be picked up by eager gardeners ready to start Spring. These same folks are likely to be disappointed by the following weekend, when nighttime lows drop below freezing again.

Now, I’m as ready for spring as the next person. And, I’m hoping that Randy’s Nursery will open this weekend so I can get a start planting perennials, which unlike the tomatoes and geraniums won’t expire when the temperatures drop.

State climatologist David Stooksbury recently issued his spring climate outlook, which he says will be influenced by a change from a neutral pattern into a mild La Nina pattern. For Georgia, Stooksbury says, this means it’s likely to be dry in the middle and southern portions of the state, while north of a Carrolton to Elberton line, the climatology is likely to produce normal rainfall. In the Georgia mountains, it’s likely to be either very wet or very dry, depending on the position of the jet stream.

Temperatures are likely to vary widely over the next month and a half:

As far as temperatures are concerned, we can expect a continuation of a wide range, especially through the middle of April.

The date of the last killing freeze, or 28 F or below, or the last frost has no relationship with the climate pattern. Knowing that Georgia is currently under the influence of a weak La Niña tells us nothing about when the last freeze will occur.

Just as important, a warm March does not tell us anything about the likelihood of a late freeze. The 2007 Easter freeze is a prime example. March 2007 had been very warm and most plants had broken their dormancy. Then a devastating freeze hit in early April.

Stooksbury also points out the snow and ice storms are not that unusual in March, either.

So get out and enjoy the upcoming weekend. Within a week’s period Georgians will have been able to play in the snow and break out the shorts and T-Shirts. That’s one reason I like Georgia weather. But, hold off on those annuals until after the Master’s tournament in April.

Tropical storm Fay continues to thrash around the Florida coast near Daytona Beach, and if the area was in a drought before, it certainly isn’t in one now. Total rainfall of up to 30 inches has been reported in some areas, with one observer in Brevard Country reporting 11.21 inches of rain in 24 hours ending this morning. Of course, rain amounts can vary widely over a local area. Here are some rain reports from NWS stations around Florida:

There have been reports of widespread flooding in Florida including 30 inch high water reaching up to front porches and car doors. The rising water has brought a variety of sea creatures on the runway at the Melbourne airport according to WSB radio, and the AP is reporting residents finding alligators swimming around neighborhoods looking for dry land.

Fay will begin to turn west overnight, but her center is forecast to remain in Florida and eventually on to Alabama and Mississippi as a remnant low. This won’t leave Georgia completely high and dry though. The southern part of the state will definitely see some rain from Fay, and the HPC is thinking that much of the northern part of the state could see as much as two inches on Monday and Tuesday as the high pressure system that has kept Fay so far south begins to move east, allowing Fay to recurve. There’s also a chance that we’ll see some rain over the weekend, but nothing like what we would have had if Fay’s original forecast track had been maintained.

The latest drought outlook came out today, and all of the areas in the southeast are forecast to see improvement over the next few months. Part of this may have been based on the failed forecast for fickle Fay–how’s that for alliteration–but part is also based on an above normal forecast for rain in the southeast for the 6-10 and 10-14 day outlooks as well as September. Temperatures could be above or below normal in September.

Taking a longer range view, the Farmer’s Almanac is due to be published next week, and a news story reports the Almanac is calling for a colder than normal winter for much of the country, and above normal precipitation in the southeast in January and February.

You can choose to believe the Almanac’s forecast or not, but realistically this winter is going to be ENSO Neutral. That means that we won’t have either La Nina or El Nino conditions; sea surface temperatures in the Pacific are forecast to be normal. In neutral conditions, weather tends to vary widely, neither favoring the warm, dry conditions of La Nina or the cold, wet conditions of El Nino.

Finally, I had a chance to listen to Gwinnett congressman John Linder speak at the Chamber’s monthly lunch. Linder’s talk was brief, but he brought up the dangers of believing the human-caused global warming theory, and the costs to American society the proposed remedies would impose. He managed to tie lack of progress in becoming self sufficient in production of energy and making sure we have enough water to drink to the agenda of the environmentalists who believe that humans have caused, and can cure global warming.

The Mother’s Day weekend storm brought late-season weather misery to much of the country over the weekend, and continues to cause trouble in the Northeast US. And, it looks like the rainy weather is likely to continue.

The storm initially caused tornadoes in Oklahoma and Missouri before moving into Georgia early Sunday morning. The Atlanta area was placed under a tornado watch as early as Saturday afternoon and the storms struck overnight, with two EF2 tornadoes striking in Carroll and Douglas counties shortly after 4 AM. It had a 25 mile long path, and caused large scale property damage.

An hour later, a third tornado tore into Clayton county near I-675. Also an EF2, this storm had a 13 mile track into Henry, Rockdale and Newton counties with wind speeds of up to 130 MPH. Further south, yet another EF2 tornado caused considerable damage in the city of Macon when it went through Bibb and Twiggs counties, including destroying two businesses and creating a lot of damage at Macon State College.

The fifth tornado caused one death and three injuries as it moved through Laurens county north of Dublin around 6:30 AM. It destroyed several mobile homes in its seven mile path. It was also an EF2. Another tornado touched down near Vidalia around 7:30 AM, and the Weather Service thinks that more tornadoes may have touched down elsewhere in the state.

After causing so much damage, the storm left the area, moving north. In its place, high pressure rushed in, bringing 30 MPH winds to the Atlanta area and causing at least one fatality in Gwinnett when the top of a tree snapped, killing a woman in Duluth. The storm is tearing through the Mid-Atlantic states today, bringing late season snow to central Pennsylvania, causing power outages in New Jersey along with gale force winds that could be compared to what one would see in a tropical storm. Intense flooding and 50 MPH winds were common in Delaware.

Another round of severe weather is possible again this weekend, beginning on Wednesday as a front moves into Georgia and then stalls south of Atlanta–eerily similar to what we saw last Friday. By Thursday, the Storm Prediction Center is calling for a better than 30% chance of severe thunderstorms lasting into the evening. The storms could stick around through the weekend, causing problems for the AT&T Classic in Duluth.

Despite causing angst for golf fans, the wet weather will be keeping the drought at bay. We’ve already had more rain this month than all of May last year, and with storms predicted for the next two weekends, we’re likely to end up with near-normal precipitation for the fourth month in a row. The Weather Service has officially acknowledged that the La Nina conditions are dissipating and should be gone by midsummer, which also bodes well for normal rainfall.

The Climate Prediction Center is issued it’s latest update to its Drought Outlook for November through January. The forecast relies both on the current drought conditions in the southeast, along with the typical weather patterns seen during La Nina winters.

The latest outlook, shown at right, calls for the development of drought conditions along virtually all of the Gulf Coast, and the Atlantic Coast, from the Georgia border south through Florida. This change from the previous forecast is in line with what would be expected in a La Nina winter, which calls for dry conditions in the southeast, and with the end of the 2007 hurricane season on November 30th.

Meanwhile, the forecast calls for some improvement in Tennessee and Kentucky, which typically receive more precipitation during La Nina winters. For the portions of Georgia already in an exceptional drought, well, no changes there.

Last week’s rain did little to improve drought conditions in Georgia, although it did provide some relief to Alabama and the Carolinas:

There were virtually no changes to the drought levels in Georgia, with 32% remaining in an exceptional drought. Meanwhile in Alabama, 36% of the state remains in exceptional drought conditions, compared to 64% last week, with the western part of the state experiencing the greatest relief. North Carolina went from 56% of the state in exceptional drought conditions to 13%.

There appears to be no short term relief in sight for the dry weather conditions in Georgia. Medium range forecasts call for less than normal precipitation for the next two weeks. It’s also likely to be cooler than normal, although we might be able to get through at least another week without having a freeze.

The updated monthly forecast for November, issued yesterday, calls for equal chances of above or below normal temperatures for the entire country, except for west of the Rocky Mountains and Alaska. The precipitation outlook calls for equal chances of above or below normal rainfall for the east coast (including Georgia) and the Southern Plains, and below normal precipitation for the rest of the United States.

Georgia State Climatologist David Stooksbury held a press conference today in Athens to discuss the latest Georgia drought conditions, and to explain what he thinks might occur weather-wise over the winter and spring of 2008. Much of what might happen through the next six months depends on the strength of the developing La Nina, including the chances of being able to refill, at least partially, Lakes Lanier and Allatoona.

There is now general agreement that La Nina conditions are developing in the Pacific. La Nina, and her partner El Nino, are descriptions of the two phases of the warmth of the Pacific Ocean surface temperatures compared to normal. In El Nino conditions, temperatures are warmer, while the reverse is true for La Nina. Most climate observers feel that La Nina conditions strengthened in September.

In a press release accompanying the news conference, Stooksbury said,

“The effects of the La Niña pattern differ with its strength. These differences are critical across north and central Georgia, potentially having major impacts on the current drought and the region’s ability to recover this winter and spring.”

If the La Nina conditions remain weak, then there is actually a greater chance of precipitation across extremely north Georgia, and normal precipitation across the piedmont area. In a moderate to strong La Nina, the chance of more than usual precipitation will be limited to the extreme northwest corner of the state. In either case, it’s likely to be warmer and drier over the southern half of the state. You can see the impacts in the image to the right (click on it for a larger version.)

We had best be hoping for a weak La Nina pattern. In the words of Stooksbury,

“If a moderate La Niña pattern develops, there is a high likelihood that north and west Georgia won’t be able to recover from the drought this winter.

The extreme- to exceptional-drought regions of the state may muddle through the winter and early spring. But without significant recharge of the soil moisture, groundwater, streams and reservoirs, conditions next summer could become catastrophic.”

Accuweather.com has released its Winter 2007-2008 forecast, and it calls for much warmer temperatures than normal for most of the country. Long range forecaster Joe Bastardi says that the beginning and end of the season will probably be closest to normal, but the period from mid-December through February could be one of the top ten warmest winter periods, with the bulk of the warmth centered over the Tennessee Valley and the Carolinas.

Bastardi also has a warning for the drought starved southeast:

“We will know in the next three to four weeks whether a storm from the tropics might arrive to help the southeast drought situation. If that doesn’t materialize, those states are looking at a very dry winter, with precipitation amounts less than half of normal in some areas.”

A combination of La Nina conditions and warming Atlantic Ocean temperatures are the chief culprits for the warm weather. East of a line from the Great Lakes to the Southwest could see temperatures above normal 75% of the time.

Update 10/25/07 – here’s a link to a more detailed winter forecast from Accuweather.