I almost hate to talk about it, in fear of creating a jinx, but it looks like the Atlanta area could get some rain starting late next week.  The last time we had any rainfall at all, either here or Atlanta Hartsfield was back on September 11th, when .01 inches was recorded.  That means we are at 23 days and counting without rain. Now, models are indicating a trough will begin to move from west to east, and could bring rain sometime Wednesday or Thursday.  It may not be one of these one hour wonders either.  Accuweather says that the rain will stick around through next weekend, bringing almost two inches by Columbus Day. The CPC extended outlook calls for above normal rainfall in the 6-10 day period and weather.com is less optimistic, with rain only on Wednesday or Thursday.

I did the annual fall aerating and overseeding for my fescue lawn two weeks ago, which means that I get a pass from the watering restrictions, and can turn on my irrigation system on the appropriate odd/evn schedule.  Even with watering, when I’ve dug a few holes to plant some new bulbs and shrubs, I’m amazed at how dry the ground is. The rain, if it comes, will be much appreciated.

Another thing we haven’t seen in a while is freezing temperatures.  While North Georgia typically doesn’t get its first frost until the second week of November, Michigan, Vermont and Maine are seening freezing temperatures over the next few days.  Nationwide, the lowest temperature this morning was 17 in Stonington, Michigan.  There’s a frost advisory tonight starting in Western Michigan and moving east through northen Ohio, much of northern Pennsylvania and southern New York.  And, snow has begun to fall in the Rocky Mountains, including areas of Utah and Colorado, where a few inches are predicted through tomorrow evening.

You can keep up with the approach of winter on our Winter Weather page.  It’s just a matter of time before we begin to feel winter’s effects here in Georgia.

It’s been almost two weeks since I’ve posted… partially because of some well-deserved vacation, partially because, at least here in North Georgia, a fairly quiet weather pattern, and partially because of some other interesting events taking up my web time.

So, what did we miss. After a few weeks of quiet on the tropical front, last week brought Hurricane Kyle, which was notable in that in the first time in 17 years or so, a hurricane made landfall in Canada. Right now, Subtropical Storm Laura is on her way to England, apparently, bothering no one, really. And then there was the storm that didn’t get named despite showing some tropical characteristics—including an eye, but brought rain to the Carolinas and up into the Mid-Atlantic states.

During all this turmoil, weatherwise and otherwise, the Atlanta area stayed dry.  I’ve recorded less than 2/3 of an inch of rain this month, and the official rain gauge at Hartsfield airport shows 3/4 of an inch, with no meaningful precipitation since back on the 12th.  That’s about 3 inches less than a normal September, although one only has to go back to 2005 to find less, when we only had a quarter of an inch.  The final total could change, since there are some storms in the area tonight, but it’s highly likely that we’ll go through another month with below-normal rainfall.

If you have looked at the morning weather forecasts over the past few days, you might have noticed that high temperatures did not reach what was predicted. Despite forecasts for the mid 70s today, the high in Lawrenceville didn’t make it above 68. On Tuesday, the high was 75 in Lawrenceville, and 80 in Atlanta.

Blame the whole thing on cold air damming, popularly known as the wedge effect, where high pressure at the surface is trapped by the mountains and is overrun by lower pressure. We’ve got a high located near the Georgia/North Carolina border that is interacting with lower pressure arriving from the west. Since air at high pressure is heavier than air at low pressure, the lower pressure air forms a ‘blanket’ over the high pressure, causing cloudiness, lower temperatures, and winds from the east.

Tuesday, the damming effect wasn’t as pronounced, and ended just west of Gwinnett, so Atlanta wasn’t affected, and got warmer than it did further east. As the high moved further south, it got stronger, affecting a wider area today.

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Well, it looks like those predictions for all that rain this week didn’t exactly come true. Despite predictions of one to two inches made as late as Monday, most of the Atlanta area received less than an inch of rain from the storm.

The official rain gauge in Atlanta recorded .53 inches of precipitation as of 8 this morning. Other locations include Chamblee with .28 inches, Marietta with .24 inches, Macon with .69 inches and Athens with .35 inches. Isolated areas got soaked, though. Brunswick reported 1.6 inches, Cordele had an inch and a half, Plains had 2.37 inches and it looks like West Point got the day’s highest rainfall, with 2.97 inches. However, a few miles away in Columbus, then had .7 inches, so the possibility of ‘isolated heavy rainfall’ did come true in a few locations.

I guess you could say that in the battle of pressures, the high pressure won out. The dry air and the very nice weather we had over the weekend had to be forced out in order to get the moist rain producing tropical air into the northern half of the state. As late as 4 PM, the dew point hadn’t gone above 60, and we had a case of cold air damming–unusual in the summer–where the high pressure was being forced up against the mountains, giving the low pressure nowhere to go.

All of this could result in another typical winter phenomenon, a Nor’Easter running up the Atlantic coast, bringing heavy precipitation to the mid-Atlantic and New England. The low will seek its escape out into the Atlantic and keep moving north, bringing unneeded rain to the northeast. Between the CAD (which because it was summer, wasn’t really that cold) and the Nor’Easter, this storm was more typical of what you would see in the winter, instead of the middle of August.

Of course, Fall is rapidly approaching. We’ve finally started lowering both the daily average high and low temperatures, and we’ve lost almost an hour of daylight since the beginning of summer two months ago. Due to the drought the leaves on my trees are dropping, making it look more like mid-October than mid-August, but that’s not due to the cooler weather.

The best hope for drought relief remains tropical weather, and it looks like we may see some activity beginnining this weekend. A tropical wave east of Cuba is drawing attention, and could develop into a tropical storm by the weekend. Some models have it crossing Florida into the gulf, while others keep it along the Atlantic. The northeast quadrant of a storm is the one that tends to get the most rain, so for really beneficial rainfall in north Georgia, we really need to see something come from the gulf, rather than from the Atlantic. If this wave doesn’t do the trick, however, there will likely be others behind it.

The August heat wave looks like it will go on through Thursday, but at least here at my house, today was the warmest day so far in 2008. It got up to 99 degrees (well, 98.7) at 2:10 PM, topping the 97.1 reached on both June 8 and July 10. It could have been worse though: with the dew point in the low 60s, the heat index was only 102 degrees.

Temperatures reached the century mark today in Augusta, Milledgeville, Savannah, Athens and Vidalia. For whatever reason, it stayed a bit cooler in Atlanta today, with highs only in the low 90s. Tomorrow, the humidity goes back up, and by tomorrow afternoon, the approaching front will bring a chance of rainfall, and at least a temporary end to the excessive heat we’ve been seeing recently.

Hurricane Forecast Update

We’re about ready to get into the strongest part of the hurricane season, from mid-August through the end of October.  The folks at Colorado State University have updated their tropical forecast and are now calling for more storms than they predicted back in April and repeated in June.

Instead of 15 named storms, the predicted total has been upped to 17, with nine hurricanes, instead of eight. Five of those should be intense, compared to four predicted previously.  Part of the reason for upping the predictions is the number of storms we’ve seen through July, with four named storms, two hurricanes and one intense hurricane. That doesn’t count Edouard, which was the first storm in August.  According to the forecast, only 2005 (the year of Katrina) and 1916 have had more active pre-August tropical activity.

There’s a 2/3 chance of a major hurricane making landfall somewhere in the US during the rest of the season, with a better than 40% chance of a storm striking either the east coast or the gulf coast.  Overall, the forecasters are predicting a tropical season that is 190% as active than the average season from 1950-2000.

In addition to providing forecasts for the rest of the season, the Dr. Gray and his team are providing a forecast for August tropical activity. If they are right, we will have four storms, three of which will become hurricanes, and one intense hurricane this month. With Edouard already occuring, that’s the non-hurricane storm, if their forecast is correct. They will also issue forecasts for September and October at the beginning of those months.