Excessive Heat Advisory Through Thursday

...HEAT ADVISORY IN EFFECT FROM 1 PM EDT /12 PM CDT/ WEDNESDAY TO
8 PM EDT /7 PM CDT/ THURSDAY...

THE NATIONAL WEATHER SERVICE IN MORRISTOWN HAS ISSUED A HEAT
ADVISORY...WHICH IS IN EFFECT FROM 1 PM EDT /12 PM CDT/ WEDNESDAY
TO 8 PM EDT /7 PM CDT/ THURSDAY.

HEAT INDEX VALUES WILL REACH 100 TO 105 ACROSS SOUTHEAST TENNESSEE
DURING THE AFTERNOON.

A HEAT ADVISORY MEANS THAT A PERIOD OF VERY HOT CONDITIONS IS
EXPECTED OR OCCURRING. HOT TEMPERATURES AND HIGH HUMIDITY WILL
COMBINE TO CREATE A SITUATION IN WHICH HEAT ILLNESSES ARE
POSSIBLE. AVOID PROLONGED WORK IN THE SUN OR IN POORLY VENTILATED
AREAS...DRINK PLENTY OF WATER AND OTHER NON-ALCOHOLIC BEVERAGES...
AND SPEND AS MUCH TIME AS POSSIBLE IN AN AIR CONDITIONED
ENVIRONMENT.

Hurricane Forecast Remains Above Normal

The hurricane forecast team of Dr. William Gray and Phillip Klotzbach at Colorado State University have released their forecast for the remainder or "peak" of the hurricane season. Each season, regularly scheduled updates are released to apply June and July weather conditions to the forecast for the remainder of the season. Their newest update includes a slight reduction from the 17 expected named storms in their June 1st forecast. However, the overall numbers remain well above normal. As of August 2, there have been 3 named storms. Their forecast calls for an additional 13 named storms, with 8 of those possibly becoming hurricanes. Of those 8 hurricanes, 4 could become major hurricanes (category 3 and above). This means that the season total could be between 15-16 named storms. The Gray/Klotzbach team expects a 44% chance of a major hurricane affecting the US Gulf Coast (the normal risk is 30%). The U.S. East Coast is given a 43% risk of a major hurricane making landfall. One very important factor to remember about these forecasts is that the "number of storms" is not the main factor. The fact that they are expecting 13-15 storms indicates a value that is above the normal trend of 10 named storms per year. So, they are favoring another above normal season as we head into the most dangerous part of the season.

The reason behind their slight reduction in the number of expected storms is due to the fact that the sea surface temperatures (SSTs) in the tropical Atlantic have cooled during July. However, a lack of EL Nino resulting in cooler waters off South America may mean less wind shear in the tropics to prevent storm formation. Conditions such as this have led to busier than normal seasons. And, even though the tropical Atlantic breeding ground is slightly cooler, The Gulf waters are above normal, thus the above normal risk to the Gulf states.

So, what does this mean for the Tennessee Valley? Well, in some of my earlier postings I have stated that an active Gulf season can help produce above average rainfall locally depending upon the path of the storm. Since 1995, storms such as Opal and Ivan brought soaking rains locally, but also unfortunately produced some wind damage. Atlantic storms tend not to bring much rain our way. We are often times on the drier west side of storms that make landfall along the Carolina coast.

Here is a link to the full report: Gray/Klotzbach Hurricane Forecast Update

July 2007 Recap

July 2007 was just what the doctor ordered! Suffering through the worst drought in decades, the weather pattern during July was a nice change. Let's start with the temperatures. The average temperature was 78.3 degrees, which was 1.3 degrees below normal. The coolest morning was late in the month on the 21st with 62 degrees. We had 14 mornings with temperatures in the 60s. The hottest temperature was 93 degrees which occurred on the 8th and 9th. Now, for the most important statistic of the month, rainfall. 7.18 inches of rain was recorded at Lovell Field, which was 2.45 inches above normal. July was the wettest month of 2007 so far. In fact, July was the wettest month in 32 months. You have to go back to November 2004 to find a wetter month in Chattanooga, when 6.60 inches of rainfall was received. The first day of August continued the "wet" trend, with 0.53 inches recorded. Our yearly deficit still stands at over 12 inches, which will be hard to overcome. However, more months like July will help ease us out of the drought in the long term.

TD3 Becomes Tropical Storm Chantal...No Threat to U.S.

Chantal is no threat to the U.S. It is moving rapidly northeast as it is being absorbed by a cold front. Chantal should begin to lose its tropical characteristics and become "extratropical". Even though it will not be "tropical", it will still gain a little strength as it passes off the coast of Newfoundland and across the north Atlantic. This storm will be a menace to shipping through the end of the week and the weekend. The National Hurricane Center has issued the last advisories on Chantal as of 11pm Tuesday.

Another area being watched for possible development is a tropical wave east of the Windward Islands. The system remained disorganized Tuesday, but environmental conditions appear favorable for future development. Hurricane Hunter aircraft is scheduled to investigate this system, if necessary Wednesday.

A non tropical low pressure system is off the Carolina coast, and should remain offshore as it moves northeast.

Tropics Starting to Stir

It comes as no surprise that activity is beginning to stir in the tropical regions of the western Atlantic. As i mentioned in my post from last week, the start of August signals the start of the busier time of year for tropical weather. There are two features being watched. The first is Tropical Depression 3 east of Bermuda. It is an area of low pressure which has slowly become more organized. Its window of opportunity for development to a tropical storm is starting to close as this low should get absorbed by a cold front and get shoved rapidly northeast off the US coast. It could affect the Canadian Maritimes as a tropical storm. The second area to watch is a tropical wave that is getting better organized a couple of hundred miles east of the Lesser Antilles. Computer model guidance is suggesting a general west-northwest movement as it moves into the warm waters of the Caribbean Sea. Some further development is possible.

Record Breaking Rainfall Saturday

2.74 inches of rain was recorded at Lovell Field in Chattanooga on Saturday. That total now stands as a record for the most rain received for a July 28th. The record rainfall also boosted our monthly rainfall total for July to 7.18 inches, which is 2.86 inches above normal for the month. We still have a huge deficit for the year, but it has been whittled away to 12.23 inches. However, since June 1, we have experienced above normal rainfall with 9.20 inches received. that total is 0.89 inches above normal. July has been a terrific start to the second half of the year concerning rainfall.

Hurricane Season Has Only Just Begun!

Hurricane season begins every year on June 1. But, the "real" hurricane season really kicks off August 1. If a hurricane season was compared to an NFL season, we would still only be in the preseason. I spent the last 8 hurricane seasons on the Alabama/Florida Gulf coast. I was able to forecast and experience some of the most destructive hurricanes in US history (Ivan and Katrina). Granted, we did have a few early season hurricanes in June and July (Dennis in 2005), but the true meat of the season gets underway after August 1. I have already seen a few national news reports that are a little premature and impatient with their reporting claiming that the 2007 hurricane season is a bust. The hurricane season is a long way from being over, and here are some stats to drive home this point.
During an "average" hurricane season, the first named storm usually occurs by July 10. For 2007, we are already ahead of schedule with Tropical Storm Andrea occuring in May and Tropical Storm Barry on June 1-2. The first hurricane of an average season should occur by August 14th, which is still 3 weeks away. The first major hurricane of an average season typically occurs by September 3rd (6 weeks from now). The statistical peak of the season is not until September 10th. So, as these statistics show, its way to early to call the 2007 season a bust. The extremely busy 2004 season really did not get cranked up until the second week of August with Bonnie and Charley hitting Florida just 2 days apart.
The available heat potential in the Gulf is above normal, but lower in the western Atlantic. So, the Gulf coast has conditions which are ripe for sustaining a developed storm should one move into the Gulf basin. The position of the Bermuda High off the US east coast is providing an alley way which still tends to favor Florida and the central/eastern Gulf for tropical activity.
So, as the "preseason" ends and the busy part of the season kicks off, you can depend on the Storm Track 9 team to keep you posted of storms that could affect your beach plans and those that could have some local impact.

Interesting Editorial from the Wall Street Journal written by hurricane expert Dr. William Gray - (Link)