Despite threats of 4-5 inches of rain along the I-85 corridor due to the remnants of Hurricane Ida, it appears that most of the Atlanta area only received in the neighborhood of 2-3 inches of precipitation. Here in Lawrenceville, I’ve recorded 1.87 inches since the rain started early this morning. In Alpharetta, they recorded 3.11 inches, and in Johns Creek, the Atlanta Athletic Club measured 2.98 inches.

Other Georgia locations received much more rain. Pine Mountain was reporting 5.48 inches of rainfall today, while Columbus recorded 5.01 inches. These two areas seem to be the hardest hit, and from glancing at the radar this afternoon, it seems that Alabama got the most rain. Gainesville recorded 2.44 inches, while Marietta saw 2.77 inches. The official Atlanta rain gauge at Hartsfield Airport recorded 2.71 inches.

The rain did cause some area rivers to reach flood stage. Big Creek in Alpharetta is flooding, as is Pew Creek in Gwinnett County, Peachtree Creek in Atlanta, and the Nickajack Creek in Cobb county. Suwanee Creek is expected to experience minor flooding tomorrow morning.

There’s still more rain to come before Ida bids Georgia farewell (and her remnants cause problems in the Delmarva peninsula). But, looking at the radar now, it seems like the forecasters should have picked I-59 in Alabama as the worst hit area, rather then the I-85 corridor.

I hope you enjoyed the beautiful weather today, with highs eight degrees above normal. In fact, the last week is the first time we’ve gone seven days without any rain since the middle of August. That’s about to change.

The map to the right tells the story. A combination of a cold front, a low pressure system now over Texas, and Hurricane Ida will bring as much as four inches of rain to north Georgia beginning Monday night through Wednesday morning.

Much will depend on Ida’s exact path. While the official forecast from the Hurricane Center takes her path over extreme south Georgia, the GFS and Canadian models are much further north, passing over the Atlanta area. Over the past few forecast updates, the Hurricane Center has brought Ida’s path further north.

The Weather Service has issued a flash flood watch for much of North Georgia from Tuesday morning through Wednesday morning. Despite the lack of rain over the last week, the ground is still extremely wet, and any rain over two inches or so could trigger yet more flooding.

Excuse the punning, but it looks like Ida has formed in the southern Gulf of Mexico, and she could be heading our way. Ida became a tropical storm late Wednesday and has since hit land over Nicaragua and Honduras, reducing her intensity to a tropical depression.

Once she emerges over water, she is expected to return to tropical storm state, and her path is taking her north over the Gulf of Mexico towards the Florida panhandle. While nothing is certain (the storm wouldn’t make it to the US coast until next Wednesday at the earliest), there’s a possibility Georgia could see some tropical weather this year after all.

This morning , the National Hurricane Center announced the formation of another tropical storm. Danny is the fourth tropical event of the season, and he looks to be roughly following the path of Hurricane Bill.

However, Danny isn’t expected to be as powerful as Bill was, and he is more likely to interact with the regular weather systems over the United States, especially a trough that is expected to develop over the Great Lakes. As a result, there is a little more uncertainty in the storm’s path. While the current official forecast keeps Danny to the east of the US east coast, the Canadian model puts the storm over the Outer Banks of North Carolina, and then along the east coast through the New Jersey Shore, and then north over land. Either way the Georgia coast is likely in the clear.

As a result, this could be the second interesting weekend in a row for the Northeast US. Stay tuned.

Hurricane Bill became a powerful Category 4 hurricane this morning, with winds estimated to be at 135 MPH, and the barometric pressure estimated to be 28.05 inches. The storm was moving west-northwest at 18 MPH.

Forecasters expect Bill to continue to strengthen somewhat over the next three days. Then, he will interact with a low pressure system coming east across the US. This will cause a northward turn, and at this point anyway, the storm is expected to recurve east without hitting the US coast. Vacationers and residents along the southeast coast will probably feel Bill’s effects with stronger waves and winds than normal.

NOAA satellites have been keeping an eye on Bill’s progress, and today, they released an animated series of images showing Bill’s progress between around 7:15 this morning and 12:15 this afternoon. Click on the still image below to bring up the animation in a new window. Fortunately Bill is passing north and east of the Caribbean islands – they’ll get some wind, but not the storm they would see if the storm were to the west.

The tropical weather picture remains busy. This morning, the Hurricane Center upgraded a tropical wave in the Gulf of Mexico to a tropical depression, Tropical Depression Four. Four is located off the Florida coast, and is expected to make landfall in the Florida panhandle sometime late tonight. By that time, the depression will probably be upgraded to Tropical Storm Claudette, with maximum winds of 45 knots. By Monday afternoon, the storm is forecast to dissipate in western Alabama.

So, how is the storm likely to affect Georgia in general, and the Atlanta area in particular? An area of high pressure to our northeast should keep the center of the storm in Alabama, and the storm is fairly compact. However, since Georgia is on the east side of the storm, we can expect lots of moisture in the air with a good chance of at least some rain.

The weather service is predicting the best chances of rain west of a line from Rome to Miledgeville, which would cut through the center of Atlanta. There is a chance that affected areas could receive up to four inches of rain, with one to two inches more likely the norm.

Meanwhile, Tropical Storm Ana is expected to weaken as she passes over Hispaniola and Cuba, and the latest outlook is that she will diminish to a tropical depression near Key West by early Friday. It looks like TS Bill will pass north of the Caribbean islands and remain an east coast storm rather than going into the Gulf.

On Tuesday, I wrote about Tropical Depression Two, which at the time was expected to become a tropical storm. Two vanished temporarily, the victim of dry air and wind shear, but now has reappeared as Tropical Storm Ana. She is forecast to remain a tropical storm as she moves westward, and is expected to strike the south Florida coast on Thursday morning. Of course, right now there’s a lot of room for the path to vary, potentially south of Cuba or into South Carolina. While it’s possible that Ana could turn into a hurricane, the Hurricane Center says that dry air and shearing ahead is more likely to keep her a tropical storm

Ana is merely the warmup act for the newly christened Tropical Depression Three, which lies east of Ana’s position. Three became will probably become tropical storm Bill this afternoonsometime before the weekend is over, and by Thursday is predicted to be a category 2 hurricane, positions just east of Puerto Rico. Three/Bill will have an easier time developing since Ana precedes it.

It’s too early to tell if either storm will have any effect on Georgia.

It has been one of the quietest starts to the hurricane season in years. While most years have at least one named Atlantic storm in July, there have been none yet this year. The last time it took this long to get a named storm was 1992, when Hurricane Andrew hit Florida. The lack of storms is being blamed on El Nino conditions this year, which tend to produce conditions in the Atlantic that don’t favor tropical development.

We still don’t have a named storm, but are likely to get one by this time tomorrow. The National Hurricane Center has identified Tropical Depression Two forming from a wave off the African coast. The depression, which will become tropical storm Ana if it intensifies, is too far east to know where or if it will impact the US coastline.

As a followup to my earlier post on July temperatures, the NCDC released its official temperature rankings for July, and it looks like a lot of records were broken.

It was the coldest July in 115 years of recordkeeping on Iowa, Illinois, Indiana, Ohio, Pennsylvania and West Virginia, with Wisconsin, Missouri, Michigan and Kentucky having their second coldest July ever. In Georgia, it was the 15 coolest July on record.

The 90 degree temperatures we’ve seen for the last week or so have kept August about 1.5 degrees above normal so far. Today will likely be the last day we see 90 for the rest of the week, as an approaching frontal system and the attendant clouds and storms will keep temperatures down. Today is the last of the Dog Days, traditionally the hottest period of the summer, from July 3rd through August 11th. And today’s ‘normal’ low dropped by a degree from yesterday, from 71 to 70. By the end of the month, the daily average temperature will have dropped by three degrees from today’s 80.

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.

Although the official hurricane season doesn’t officially get started until Monday, June 1, the first tropical depression of the season was declared earlier today. Tropical Depression One lies over the Gulf Stream to the east of Virginia, and may develop into Tropical Storm Ana later tonight or Friday before it dissipates over the weekend. The storm is not expected to affect land.

The Weather Service released its 2009 hurricane season outlook recently, calling for a 50% chance of a normal season, a 25% chance of a below normal season, and a 25% chance of an above normal season. They estimate 9 to 14 named storms, with four to seven hurricanes, and one to three major hurricanes.

Meanwhile, Accuweather’s Joe Bastardi is calling for a lighter than normal hurricane season. He is predicting three storms with tropical force winds to reach the US coast, with possibly two being hurricanes and one being a major hurricane. This compares to eight storms affecting the US coast in 2008, with four hurricanes and no major hurricanes.

Storm names for 2009 are Ana, Bill, Claudette, Danny, Erika, Fred, Grace, Henri, Ida, Joaquin, Kate, Larry, Mindy, Nicholas, Odette, Peter, Rose, Sam, Teresa, Victor and Wanda.

Keep up with tropical weather activity this season at our Tropical Center.