The latest drought report, as of July 14th, lists just over one third of the state of Georgia as being abnormally dry, including metro Atlanta and Gwinnett. This is despite the one to three inches of rain that fell on Sunday. While this may seem ominous, keep in mind that a year ago over half the state was in a severe drought.

The other bit of good news is that the drought outlook isn’t calling for any drought to develop east of the Mississippi River through October. There’s a better than even chance for precipitation tonight and tomorrow, and both the 6-10 and 8-14 day precipitation outlooks for Georgia are calling for wetter then normal weather.

In addition, both the one month and three month outlooks for August and August through October are calling for equal chances of above and below normal temperature and precipitation.

A month after the climatologists said that the North Georgia drought was over, the state Environmental Protection Division has caught up. As of today, most watering restrictions have been lifted throughout the region. You are still limited to watering on your assigned odd-even days, either Monday, Wednesday and Saturday or Tuesday, Thursday and Sunday, but you can water any time you like.

The EPD does recommend that you not water between 10 AM and 4 PM, since during those hours more water can be lost to evaporation, making watering less useful. This is a return to level one watering restrictions. Level two restrictions, which we were under for much of 2007, limited watering to between midnight and 10 AM. We never were subjected to level 3 restrictions, which would have limited watering to a single day a week.

Before you turn on those sprinklers full blast, though, be aware that water rates have changed since the last time we were drought free. The big change is a summer surcharge for excessive water use. For example, in Gwinnett County, you could pay twice the normal rate per 1,000 gallons for amounts above 20% of your average use from January through March.

Compared to the past few years, the weather this spring in North Georgia has been wet. Virtually the entire state reported above-normal rainfall in April, which followed a wetter than normal March.

Some unofficial reports of rainfall totals in April were over ten inches in South Georgia, while the highest official total was 7.3 inches in Alma, over four inches above normal. Atlanta was 1.56 inches above normal for April, and Athens had 1.12 inches above normal precipitation.

May has gotten off to a wet start as well. As of May 6th, Atlanta had recorded 2.05 inches of rain, which is 1.31 inches above normal for the first week in May. With this morning’s storms and chances of more wet weather still ahead through the weekend, we are close to reaching the 2.8 inches of precipitation recorded for all of May, 2008, and will have more May rain than since at least 2004. Normal May rainfall in Atlanta is 3.95 inches for the entire month.

Lake Lanier continues to fill as well. The lake level is at 1064.95 feet at Buford Dam, 7 inches above where it was when the current rains started a week ago, and just six feet below full pool.

The latest drought outlook from the Climate Prediction Center says,

Several inches of precipitation are forecast in the short-term for the last vestiges of the once expansive drought that covered the interior Southeast. Given the expected heavy precipitation through the forthcoming weekend, and nothing indicating enhanced probabilities for significantly below-normal rainfall through the end of July, it seems likely that we will finally be able to close the books on this protracted and at one time serious, large-scale drought that has been affecting the Southeast for the last 3 years.

And, State Climatologist David Stooksbury reported earlier this week that conditions on Lakes Lanier and Hartwell have improved to mild drought from moderate drought because of the increasing lake levels. The rest of the state is drought free. He reports above normal soil moisture for most of the state, and normal to above normal stream flows. He says,

May is typically one of the drier months in Georgia. Additionally, with high temperatures routinely in the 80s and plant water use very high, moisture loss is accelerated. We normally expect the soils to start to dry out this month.

As we progress through the summer into the middle of fall, moisture loss from the soil – due to evaporation and plant use – is normally greater than rainfall. With normal weather over the next several months, Georgians can expect to see a drying of the soils. However, this is normal and does not mean that Georgia is heading back into a drought.

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.

As far as the weather goes, winter is almost over, and with it, the best chance for reducing Georgia’s long-term drought. However, looking at the rainfall we’ve had for the first two months of the year, we are woefully behind where we should be. As of this morning, we’ve had 4.39 inches of rain in Lawrenceville, compared to a normal of 9.19 inches, or 48%. Atlanta is doing even worse, with only 3.84 inches, or 42% of normal rainfall.

Most of the state is now listed as being in some sort of drought, as you can see in the map to the right. The biggest change over the last week is that the part of the state in moderate drought has increased from 30% to 76%. Less than 1% of the state is drought free.

In his latest assessment, state climatologist David Stooksbury says,

The cool season – October through April – is critical for the state. That’s when it typically receives moisture recharge to the soils, groundwater, rivers and reservoirs. Without significant rain in the next two months, Georgia is primed for another year of drought.

The major reservoirs of Lanier, Hartwell, Russell and Clarks Hill remain near record lows with diminishing hope for recharge unless there is a major weather pattern shift over the next few months.

This weekend does promise to bring some relief, with rain predicted for much of the northern half of the state on Friday and Saturday. Accuweather is forecasting 2.25 inches of rain for Gwinnett over the period, while the weather service says there could be nearly four inches of rain in parts of north Georgia, with the western half of the state more likely to get the heaviest rainfall.

However, once this system moves on through, the outlook for much of March, and indeed the Spring months is for drier than normal conditions for much of the Southeast. Lake Lanier stands at 1056.9 feet, pretty much where it was after heavy rains in early January raised the lake’s level by about three feet. Rain this weekend should help some, but it doesn’t look like we’ll be getting back to normal any time soon.

The rain last week raised the water level of Lake Lanier about a foot, which likely means that Atlanta’s water supply won’t reach a record low in 2008. As usual, the mainstream media issued stories which said that the rain is good, but the drought isn’t over yet, we’ve got a long way to go, etc. &ct.

Now comes the Southeast River Forecast Center with the best estimate (PDF) I’ve seen for what it will take to get Lake Lanier to full pool — or 1071 feet above sea level, about 20 feet higher than where it is today.

Surprisingly, it’s only 10% above normal rainfall for a year.

The forecast center measured annual precipitation against Lake Lanier’s level since the lake began to fill back in 1952.  It determined that, on average, 60 inches of rain fell in the lake’s drainage basin per year, providing about 1.36 million acre feet of water.  Using those figures, and accounting for the fact that the Corps of Engineers has restricted the outflow from Lanier over the past year, the Forecast Center says,

Lake Lanier’s pool was at 1054 feet msl at the beginning of this water year (1.37 million acre-ft). To get to full pool at elevation 1071 feet msl, an additional 585,000 acre-ft of inflow is needed. However, this assumes no outflow. If we apply the annual average outflow of last year for this year (1070 cfs), 775,000 acre-ft are released downstream. So the total inflow volume needed to fill the reservoir and sustain a release similar to last year is 1.36 million acre-ft.
…[T]his would put the total annual precipitation at around 65 inches (following the lower end of the trend). This is only about 10% above normal.

Of course, part of the equation depends on when the water comes. If we get a lot of excessive rain in the winter, it will count more than if we get it in the summer, since the heat and absorption by plants prior to the water reaching the lake will be higher in the summer months. The calculations used in the analysis are based on rain during the water year, which starts on October 1, and there has already been six inches of rainfall. That means there are only 59 inches to go.

I listened to Lieutenant Governor Casey Cagle (who is clearly running to become governor in 2010) addressing the Gwinnett Chamber’s monthly meeting this afternoon. He dumped most of the problems with metro Atlanta’s water supply on the Corps of Engineers favoring mussels in Apalachicola Bay over the water needs of Georgia. He also offered an innovative idea for increasing the water available to metro Atlanta. He estimated 10% of the lake’s capacity had been lost due to silt (something I’m not going to argue with). By dredging the lake, Cagle says we could not only expand the lake’s capacity to hold more water, we could recycle and resell any valuable materials that were dredged up.

In my mind, Cagle’s plan will only work if Georgia gets some formal rights to the lake’s water. Based on court decisons and the official use plan for the lake, we aren’t there yet.

If it seems colder than normal for mid-November, you’re right. North Georgia got its first cold shot on Sunday after the wet weather moved out. This afternoon, another cold front passed through, although with the dry air, there wasn’t any precipitation associated with the front. Behind the front, there’s more cold air blowing in, literally. There’s a wind advisory for Tuesday, so even though temperatures in the Atlanta area will only reach the mid 40s, it will feel like the low 30s tomorrow afternoon.

We get the coldest weather of the season so far on Wednesday morning, with lows predicted in the low 20s in metro Atlanta, and freezing temperatures as far south as the Tampa area. The cold weather is unlikely to break a record, however. The record low for November 19th in Atlanta is 18 degrees, set back in 1903. Although forecasters have predicted freezing temperatures on and off for the last few weeks, much of the Atlanta area has yet to get a freeze. Wednesday should put an end to that for everybody, making the first freeze of 2008 about ten days later than normal. The record low for Atlanta in November, by the way is 2 degrees, set on November 25th, 1950. Fortunately, it won’t get that cold.

After this round of cold, things warm up, but only slightly. We should be seeing highs around 60 and lows around 40 for the last two weeks in November, instead look for highs in the upper 50s and lows in the low to mid 30s through the end of the month. What about Thanksgiving weather? The cold, dry air is going to keep most of the US dry for the next week, and following that, there’s a chance of rain moving from west to east.

Looking at the forecast models, on Thanksgiving Day, there will be a band of rain centered along a line from Wisconsin through Texas. Light rain or snow is possible in the north from Wyoming on the west to Michigan on the east, and there’s a chance of precipitation from Arizona to Arkansas in the south. Most of the east coast, including Georgia will be dry. By Black Friday, the rain will move further east, and shoppers on the east coast could get wet, with the bulk of the precipitation centered from Mississippi to southern Ohio. Overall, the cold weather means that for any snow that does fall, it will likely stick.

So far in November, while it’s been a bit cooler than normal in north Georgia, it’s also been very dry. With .64 inches of rain recorded at Hartsfield Airport, there’s been slightly more than a third of normal precipitation month to date. The dry weather has now moved 12% of Georgia into Exceptional Drought status, compared to 1% last week. The hard-hit area includes much of the northeast corner of the state, including North Gwinnett county, and all of the Lake Lanier drainage basin. Issuing a climate report late last week, Georgia climatologist David Stooksbury said,

The ocean-atmosphere system is in what climatologist call a neutral pattern, meaning it is in neither an El Niño nor a La Niña pattern. Historically, neutral-pattern winters have been very variable.

There is no strong indication that the winter of 2008-09 will be abnormally wet or dry. The trend over the past 15 years, however, has been for dry winters.

There is also no strong indication that the winter will be abnormally warm or cool. An important historical observation is that every major devastating freeze has occurred during a neutral-pattern winter.

With recent winters being our best guide, the most prudent response is to assume that this winter will tend toward the dry side. Water conservation efforts should continue.

Finally, NASA’s Goddard Institute for Space Studies reported that October, 2008 was the warmest on record last week. Since many parts of the world were reporting earlier than normal winter conditions, the report was challenged, and found to be wrong. You can read about it here. It makes you wonder when one of the leading proponents of Global Warming makes such a big error.

This is going to be one of those grab-bag posts. Sometimes I see things in the news that are weather related, but don’t post immediately about them.There have been a few things like that recently, so here goes.

We’ll start with the drought, and more specifically, the effects on the Atlanta water supply. As Lake Lanier remains at near record low levels, Georgia EPD Director Carol Couch has asked the Army Corps of Engineers to reduce discharges from the lake to create a flow of 650 CFS at Peachtree Creek on the Chattahoochee River. This is similar to a reduction made last spring which, Couch argues, didn’t cause any environmental damage, and would save some 11.7 billion gallons of water.

Meanwhile, Senator Obama has apparently decided that Florida is more important than Georgia, telling potential Sunshine State voters he would side with them when it comes to deciding who gets water from the Apalachicola Chattahoochee Flint river basin. This prompted a quick response from Senators Isakson and Chambliss expressing their disappointment with his comments. It’s another reason to think carefully before you decide to vote for the Chosen One.

The recent cold snap tells us that Autumn is truly here. While it seemed colder than normal, Atlanta is actually registering 2.1 degrees above normal for the month through yesterday, with a mean temperature of 66.6 degrees. Here in Lawrenceville, it’s been a bit cooler than that, and I’ve noticed that early morning temperatures in other metro Atlanta locations consistently register lower than what’s recorded at the airport. (The home page and forecast pages now show current conditions for several cities in the area.) The outlook for the last week of October and the first week of November points to colder than normal temperatures (and lower than normal rainfall) for much of Georgia. We should, however, get some rain this weekend—Accuweather says to expect just less than an inch—which would give us above normal rainfall for October.

While Georgia worries about temperatures in the low 40s, other parts of the country are already getting snow. In addition to snow in the upper elevations of the Rocky Mountains (which can be expected almost any time of year), parts of New England are expecting a few inches in the next day or so. The growing season has ended for much of the northwestern US, and in the east, for parts of West Virginia, Pennsylvania and Ohio, with temperatures dropping below freezing. On average, North Georgia doesn’t drop below freezing until the second week of November. I’m still waiting for ‘official’ winter weather forecasts; they seem awfully late this year.

Finally, I’ve added (at least temporarily) more detailed forecast information at the three or six hour level to every forecast, and provided improved accuracy for the graphical 3 day and 7 day forecasts, as you can see here. There is also an hourly forecast added for every location, for example, Atlanta, which includes things like rain amounts and probability of precipitation for each period. The information tends to be more accurate than what you get in the zone forecast, which covers a fairly wide area.

I have been providing an hourly forecast for Lawrenceville all along using a Rube Goldberg type system of producing the forecast on a computer here at home and transferring it to the website. Unfortunately that method won’t scale to other locations in the way my new data source does. So, the question is, how useful are the hourly forecasts, and should I keep them? Check your city using the Get Forecast menu item above, and let me know.

And, by the way, have you noticed how Global Warming has kind of dropped out of the news lately?

I know it’s not the headline that most people want, but the latest outlook from the Climate Prediction Center doesn’t show much relief for the drought that has been plaguing north Georgia for the last two years.

The 3 month outlook for November-January indicates at least a 33% chance of less than normal precipitation for all of Georgia, and a 40% chance of drier than normal conditions for middle and south Georgia. This is backed up by the CFS forecast, which shows below normal rainfall continuing for much of the next year(!). The CFS forecast also indicates a colder than normal start to the winter season, with November and December being cold, and the first few months of 2009 being warmer than normal.

The newly published drought outlook says,

In the Southeast, streams from northern Georgia to southwestern Virginia rapidly receded following heavy rains during the first half of October. The lack of sustained recovery in stream flows reflects the intensity and duration of the long-term drought. The seasonal forecast indicates that the drought will be ongoing for the next several months, but some additional improvement is expected during the second half of October, if not beyond. In contrast, with the official November-January outlook indicating the odds tilting toward below-normal rainfall south and east of the Tennessee Valley, the drought outlook shows little change in conditions for central and southern parts of Georgia and South Carolina, and even a good chance for drought expansion into Florida.

If there’s any good news in all this, there seems to be a good chance for above normal precipitation in both the 6-10 and 10-14 day outlooks, and the outlook for November is neutral. We are likely to get about half an inch of rainfall as the front passes through on Friday. That will bring us closer to ‘normal’ rainfall for October of 3.11 inches, but I wish it were a bit more evenly spread out.

Georgia State Climatologist David Stooksbury says the drought isn’t getting any better.

Tropical Storm Fay brought beneficial rain to Georgia in late August. But a very dry September has led to the return of low stream flows across the state and worsened drought conditions.

All streams in Georgia except those originating in the extreme southern counties are extremely low. Most streams in the state’s northern half are at or near record low flows for this time of the year.

Stooksbury also says that Lake Lanier is at a record low for this time of year, and indicates that when the new Georgia drought map comes out on Thursday, it will show conditions worsening compared to the previous report.

Unfortunately, the chances of a tropical storm helping the situation are diminishing by the day:

The probability for meaningful drought relief over the next couple of weeks is low. October is still in the tropical storm season. But the likelihood of tropical weather impacting Georgia diminishes rapidly as the month progresses.

You can also look at this comment for some insight into how dry September 2008 was.