Weather forecasters are keeping an eye on an upper-level low pressure system off of the eastern Florida coast that has the possibility of developing into a tropical storm, or worse, by this weekend.

The system has brought rain and high winds to coastal areas between Miami and Savannah this week, and the expectation is that the storm will move west across Florida, and into the Gulf, where it will strengthen into a tropical storm. The picture below shows model predictions as of this afternoon:

While most of the models show the storm passing over the Tampa area, the Canadian model (in yellow) has the storm passing over Jacksonville and into Georgia and Alabama, and the CLP5 model has the storm moving up the Atlantic coast, never reaching the US coastline. Yesterday, the Atlanta Weather Service office noted the possibility of the storm bringing rain to the Atlanta area by the weekend, however, the current thinking seems to be that the storm will stay to our south.

There are still a lot of variables, and a tropical storm may never develop, but it’s worth keeping an eye on.

As of 11 this morning, the National Hurricane Center has recognized two tropical systems, one in the Atlantic, and the other in the Gulf of Mexico, near Texas. Tropical Depression Eight, which will become Ingrid, is located about 1100 miles east of the Lesser Antilles, and is moving along a similar track as did Dean and Felix. The difference, though, is that it appears that Eight’s path will take it north of Puerto Rico and Cuba, therefore making it a greater threat for landfall in the United States. There is still a long way to go with this storm however, as it won’t be approaching any land until sometime next week.

Tropical Depression Nine, which will likely become Humberto later today, is a different story. This storm has been sitting in the western Gulf of Mexico for the last few days, and is finally gaining some strength. The storm is located 85 miles southwest of Galveston, Texas, and tropical storm warnings have been issued from Port O’Connor, Texas to Louisiana.

The map at right shows some of the forecast models for the storm, which is expected to make landfall overnight tonight, and dissipate somewhere near the Louisiana - Mississippi border early Friday morning. This storm is going to interact with a cold front that is expected to pass through the Atlanta area on Friday. The exact location where these systems interact is still in doubt, but this one could be a rainmaker for parts of the southeast United States.

Early September marks the halfway point of the 2007 tropical season, and things are certainly busy, with more on the way. So far this year, we’ve had six named storms in the Atlantic basin, which is well above average. Especially notable is that there have been two category five systems, Dean and Felix, both striking the Mexican/South American coast.

The picture below was taken about 8 AM, and shows Felix striking the South American coast near the Nicaragua Honduras border:

Also today, Hurricane Henriette is making landfall on the other side of Mexico, and is forecast to head towards New Mexico and Arizona, bringing heavy rainfall to that area.

Of more concern to those of us on the Eastern seaboard is a tropical disturbance located off of the Georgia coast. This low pressure system has been milling around since last week, and has the potential to develop into a tropical storm that could bring rain to the Mid-Atlantic and New England states. The picture below shows what several models were predicting what the storm’s path could be:

Both this system and Hurricane Felix are affecting the weather in Georgia, as we are now centered between the two storms’ low pressure. This is bringing us the nice weather we have seen over the past few days. Depending on what happens with these storms, we are likely to continue to see dry weather, even if the system off the coast becomes better organized.

So what to expect as the tropical season goes on? Dr. Gray and his team have issued an updated hurricane forecast (PDF) for the rest of the season and there doesn’t seem to be any significant changes from what was earlier predicted. The team continues to predict 15 named storms, including Felix, but has dropped the number of hurricanes predicted from eight to seven. They are still predicting four intense hurricanes — we are now halfway there with Dean and Felix.

The forecast notes that through August 31st, observed tropical activity accounts for 40% of what would be seen during an average hurricane season. In a normal year, only 33% of tropical activity would be recorded during August.

Hurricane Dean, still a category four storm, is just south of Jamaica this evening. The satellite picture below was taken about 6:15 PM on Sunday, and shows the eye just below the island.

The storm is expected to intensify to category five as it heads almost due west, and will next travel over Yucatan sometime on Tuesday. The following day, it lands on the coast of Mexico, and will still be a tropical storm a day later as it will be inland.

Dean might be one of the most powerful storms measured since storm naming begun. Th tropical season is in full swing now, and it’s quite possible that a future storm Felix is brewing out in the Atlantic, and we might be paying attention to it by next weekend.

Meanwhile, something needs to be done to break the heat and drought in the southeast. Atlanta has already broken the record for number of 100 degree or more temperatures in a summer, and we could have more days with highs past the century mark this week. While the remnants of Erin earlier this week are bringing welcome rain to much of the nation, Georgia is staying stubbornly dry. Based on the current long range outlook, it could stay warm and dry until the end of the month.

Hurricane Dean has been intensifying over the past few days, and is now a Category 3 storm, with winds of 125 MPH, and a very distinct eye. By Sunday afternoon, he should be directly over the island of Jamaica, and just approaching being a Category 5 storm. A hurricane watch is out for the island.

The map above shows the a number of forecast tracks for where Dean will go after passing south of Cuba. While the consensus forecast is to keep the storm on a westerly track, notice the forecast of the GFDL model, which moves the storm northwest, and towards Louisiana. While this forecast is an outlier, the GFDL model has a tendency to be accurate, and the National Hurricane Center has noted this in its discussion, which assumes that the high pressure ridge over the southeastern US will keep Dean to the south. It will be early next week before the situation becomes clearer, but it appears this storm will be one to keep an eye on.

Meanwhile, here in Atlanta, my front yard looks like it’s the first week of October, rather than the third week of August. The almost complete lack of rainfall since the first of the month has brought the effects of the drought back with full intensity, and the dogwood and tulip trees are showing the strain by dropping their leaves.

While there are some storms in the area this evening, August has rapidly taken away any improvement we saw in our cooler, wetter July. The good news is that from this time next week through the end of the month, there’s a better than normal chance of rainfall, and this trend has been holding for the last two or three outlooks.

Meanwhile, the National Climate Data Center issued its temperature and precipitation summary for July. Georgia ended up with cooler than normal temperatures (30th coldest of 113 years), and near normal precipitation (45th driest out of 113 years). Montana, Idaho, and Wyoming had their warmest months ever, while Texas and Louisiana had their third wettest July ever.