Andy_Johnson's Blog

Tropical storm Fay took her time making her way from Key West to Pensacola spending almost a week in Florida. Fay will not be remembered for her winds but her heavy rains. Fay was the 4th wettest tropical cyclone on record to hit Florida. Rainfall was as high as 26.65" in the Windover Farms area of North Melbourne. Other wet storms were Hurricane Easy in 1950 which dropped 38.70" of rain at Yankeetown, Georges in 1998 with caused 38.46" in Munson and an unnamed hurricane in 1941 with 35.00" at Trenton.

It is interesting that despite the strength of a tropical cyclone, whether it is a tropical depression or a tropical storm or a hurricane, the main determining factor in the amount of rainfall produced is the forward speed of the system. Since Fay moved slowly she produced more rain than stronger storms. Hurricane Easy made 2 tight loops near Cedar Key over a 3 day period resulting in a record storm rainfall for Florida.

Fay also set a record by making 4 landfalls in Florida. This is unprecendented. The highest number of landfalls prior to Fay was 3. The first landfall was in Key West, the second near Marco Island, the 3rd Flagler Beach and the 4th near Apalachicola.

We now have to turn our attention to a strong tropical wave in the eastern Caribbean. At the current time it appears it will take a more southern track than Fay did for the next few days.

Last week on my blog, I mentioned the wave that eventually became Fay and that it could threaten Florida this week. It looks like that is case. I couldn't help reflecting back on 2004 when there was a similar threat. There are a lot of differences, however, between Charlie of 2004 and Fay of 2008.

First, lets look at the similarities. Charlie & Fay are both August storms. Charlie hit Florida on August 13, 2004 and Fay threatens to hit central Florida on August 19, 2004.

Both started off as tropical waves moving off of the African coast yet waited until reaching the Caribbean before becoming tropical storms. Both were recurving storms at a fairly low latitude.

Now, the differences. If you look at the image below showing the track of Charlie, you can see that it started off further south and as a result spent much more time over warm water. Fay has spent her entire named life affected either directly or indirectly by land masses (Hispaniola, Cuba and Jamaica). Of concern is the fact that Charlie intensified from a Category 2 to a Category 4 in a six hour period.

The National Hurricane Center has seen great improvement in track forecasts but not as much skill increase in intensity forecasting. So, even though at this time the forecast is for a potential Category 1 with Fay, if the track were to stay over water longer a much stronger hurricane could result. This is why we have to prepare for storms sometimes even if they don't eventually materialize since there is a potential there. Due to the unique shape of the Florida coastline (a peninsula angled slightly off of a due north/south orientation) any minor change in the course of a storm could have greatly different effects at any particular point.

With Charlie moving ashore near Punta Gorda, winds near Cayo Costa were sustained at about 145 MPH. Yet, in Tampa we only had sustained winds about 23 MPH. If Charley's track were shifted just about 25 miles to the west, Tampa would have gotten a direct hit with 145 MPH winds. That is such an unbelievably smalll difference in a tracke for such a great difference in wind. That is why we have to warm people of potential danger from hurricanes sometimes when the threat doesn't materialize. Suppose we had not warned our viewers and Charlie had tracked up the coast just 25 miles to the west.

This is the concern with Fay. The timing of the turn to the north and the amount of time spend over warm water will be critical in determining how strong it will be at final landfall. So, the best advice is to calmly prepare and plan ahead for any eventuality. It does appear that with Fay we will at least see squalls on Tuesday and at worst a strong damaging hurricane.

Even though hurricane season in the Atlantic basin officially runs from June 1 to November 30, most of the named stormed form in August, September and October. So, having already had 5 named storms by the first week in August does not bode well. Normally, only 10% of a seaon's storms develop by August 8. This is evidently the reason why the long range seasonal forecasts have increased their estimates for the season.

Of current concern are several strong tropical waves that have moved off of Africa. So far this year there have been persistent upper air troughs over the eastern seaboard that have kept the steering currents over Florida out of the west. This pattern prevents hurricanes coming from Africa from inpacting our state since they end up recurving in the Atlantic like Bertha.

There are signs that the Bermuda high will stregthen and move northward later this week into the first part of the following week. That would be at the same time that a potential tropical cyclone and possibly a hurricane would be moving near or just north of  Puerto Rico. If the long range patterns play out in that fashion, any tropical system would be steered towards somewhere along the U.S. East Coast including Florida.  In addition, hurricanes that develop from African waves are ususally more intense that others.

At any eventuality, it is important to have your personal hurricane plan in place should we be threatened at some point.

No, it wasn't your imagination. Now that the totals are in, July, 2008 was wetter and "cooler" than normal. We had several episodes of either west wind pattern events or nearly stationary system leading to above normal rainfall. Usually in the summer we potentially have one round of thunderstorms in one day. Then the temperature falls and the potential energy decreases and prevents further activity. This past week a persistant area of disturbed weather caused rounds of rain moving into the same area over and over similar to a "training" event. This system has now moved into the Gulf and could become a tropical depression or even a tropical storm.

The official total in Tampa wa 9.84", although several observer reports in our viewing aera exceeded 16". The official total was 3.35" above normal. It was also interesting that the highest temperature in Tampa during the entire month was 92. Usually we have 30 days of temperatures at 90 or above in July. This past month we only had 20. That was a nice break from the summer heat and lead to an average high of 88.6 which was 1.1 degrees below normal .

The highest amount of rain Tampa has ever had in July was 20.59" in July, 1960. That was a year in which an active hurricane season (including Cat. 4 Donna)  followed the heavy rainy season in Florida. The Southwest Florida Management District was formed afterwards in order to deal with flooding issues. Let's hope that history doesn't repeat itself this yer.

I was able to get away for a while this month and enjoy some time off. I am always curious about the way the weather is presented in other countries and got to see some samples in Italy, France and Germany. A lot of times fronts are not depicted on the television weather maps in Europe like they are here. I find that curious since frontal theory was developed in Scandinavia in the early 1900's.

I am a Florida native but I get tired of the long hot summers. It was nice to be able to enjoy the cooler weather in northern Europe. Temperatures at some of the locations I visited such as Helsinki, Oslo, St. Petersburg, Tallin and Stockholm were generally in the mid 50's at night to the lower 70's in the daytime. Rome, Naples and Pompeii were hot but not really unusual for their latitude generally running from the low 70's to near 90 in the afternoon. The difference is that I am spoiled having air conditioning here and many public places such as museums and even private places such as restaurants and stores do not have air conditioning in Europe. I am always surprised when walking through museums with priceless art and paintings such as St. Peter's at the Vatican or the Hermitage in St. Petersburg, Russia that there is no climate control in the summer. Walking along with thousands of people through the museums really amplifies the heat.

When I was in northern Europe, I was able to enjoy the longer daylight periods. In Helsinki, even though the sunset was shortly before 11 PM, twilight lingered until about 1AM. You could look to the southern sky and see the light illuminated the clouds even though it was technically "dark" above you. I was glad to be able to see a lot more of the sights since the days were so long.

I kept up with the weather here on the internet and was glad that the tropical systems all stayed away from Florida while I was gone.

It looks like we will make it through June without any tropical storms making landfall in the United States. We have never had a direct hit by a hurricane in the Bay area in July which bodes well for us, too.

I've noticed that there has been a lot of shear in the Caribbean Sea this season. The shear ventilates any tropical waves and prevents them from concentrating heat near the center. As a result, shear is an inhibiting factor for tropical cyclone development. Let's hope this trend continues into the heart of the hurricane season, which occurr in August, September and October.

There has been new research showing that African dust also inhibits tropical cyclone developement. There have been several episodes this year of large areas of African dust moving into the Atlantic, as well.

As we move into the most active part of the hurricane season beginning  in about a month let's hope the shearing and dust continues.

Usually, this time of year we get afternoon and evening thunderstorms. Occassionally, in the summer months the weather pattern is conducive for morning rains than sometimes continue or train into the afternoon. June 21 was one of those days. Tropical moisture coming northward from the Caribbean combined with moisture coming from the north ahead of an unusual front in north Florida. The result was that rain was focused across Central Florida and instead of just moving inland kept redeveloping in the Gulf and moving ashore in the same areas.

Officially, Tampa had a record daily rainfall amount on June 21,2008  of 3.08". The old record was 2.76" set in 1928. This also brings us to an above normal total for the month of June.

The other difference in the rainfall pattern yesterday was that everyone in the entire viewing area got at least some rain. In our "normal" summer pattern the activity is more randomly scattered. One nice effect of the widespread rain is that, in addition to filling the aquifer somewhat temperatures were held down. Instead of reaching our normal high of 89, Tampa only reached 83. This was a nice change from the heat of our long summers.

You have probably seen video of the unprecedented flooding in Cedar Rapids, Iowa. Cedar Rapids is on the Cedar River and has flooded hundreds of blocks of the city including the downtown area. One report that I viewed showed what looked like white water rapids in the main downtown street. Until now, the worst flooding occurred in 1993, when the River was 7 feet above flood stage. In the current 2008 flood, the river is 19.8 feet above flood stage.

In the last 10 days, nearly 12 inches of rain have fallen upstream from the river. The reason is that the weather pattern seems to be "stuck" with fronts frequently becoming stationary over the Midwest and a persistant strong jet stream that guides surface lows through the same area over and over again. The persistant jet stream, accentuated by cooler than normal temperatures north of the jet stream and warmer to the south has also been responsible for the unusually strong and prolific tornado season.

One additional feature that has added to the historic flooding is, believe it or not, the remains of a tropical feature. Remember Tropical Storm Alma in the Pacific, which indirectly caused Tropical Storm Arthur in the Caribbean from May 29- June 2? I looked at some weather maps between June 2 and June 8. Some of the moisture from Arthur moved northwest into Mexico and was drawn northward and eventually northeastward into Iowa where it interacted with a stationary front. The front focused the moisture in a narrower area and caused torrential rains in the Cedar River watershed on June 7 and June 8.

So, even though it is a bit of a stretch, Arthur, in combination with an active jet stream and several persistent stationary fronts was indirectly related to providing some of the moisture responsible for the flooding in Cedar Rapids

Officially, the huricane season in the Atlantic basin begins on June 1. The Eastern Pacific season begins May 15. Tropical Storm Alma had moved inland over Nicaragua a few days ago. A cluster of thunderstorms to the east of the storm intensified in the Caribbean on May 31 and developed into Tropical Storm Arthur. Even though the system in the Caribbean was indirectly related to Alma, it did have a seperate center.

So, the Hurricane Center decided to give the separate system it's own Atlantic name...Arthur. The strange thing about Arthur is that its center was already over land when it was upgraded from a tropical disturbance to a tropical storm.

At any rate, the 2008 hurricane season if off to an early start, beginning on May 31. That could be a sign confirming the forecasts of an active hurricane season. It also goes to show that even though we define the hurricane season as running from June 1 to November 30, nature plays by its own rules and operates under its own timing.

As I have mentioned in some of my earlier blog entries, we have had an unusally active tornado season across the country. This activity continues despite a La Nina pattern which is usually associated with drier and quieter than normal weather in the southern states. This past week, violent tornadoes struck Kansas and Colorado. While Kansas and even the plains of Colorado are associated with tornadoes the Denver metro area is not.

On Thursday a tornado a mile wide wreaked havoc in Weld County and specifically Windsor, CO, which is north-northeast of Denver. The damage looks like at least an EF3 on the Enhanced Fujita scale. At least one person was killed and the wide tornado threw cars up into the air. When tornadoes are that wide it is hard to see where the actual funnel is located if you are close to the tornado.

Usually, at the latitiude of northern Colorado, weather systems move from west to east. The jet stream usually follows a generally west to east path, as well. Since the mountains and cool weather comes off of the Rockies, normally tornadoes do not develop until the weather systems hit the Plains east of Denver. They normally move eastward or northeastward towards Kansas.

However, on Thursday the jet stream was in an unusual position. It formed what is referred to as an "Omega block". It is thus named because the jet stream flows like the Greek letter Omega. Since the Denver area was near the bottom left of the "Omega" the jet stream was coming from an unusual southeast direction. This unusual configuration brought the tornadoes from the Plains back towards the Front Range of the Rockies. I'm sure it was a scary sight seeing a mile wide tornado, especially in an area not known to experience many tornadoes.

Hurricane names are decided by the World Meteorological Organization. There is a set of 6 names in the Atlantic basin, which includes the North Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico. If a storm is very deadly or costly, the name is retired. This is done for sensitivity reasons, as well as, for historical reference reasons.

The Regional Association IV Hurricane Committee decided this week to retire three names from the 2007 hurricane season - Dean, Felix and Noel. These storms caused extensive damage and many deaths. The new names will be Dorian, Fernand and Nestor in 2013. The other names from 2007 will remain the same in 2013.

We have seen an unusally active tornado season in 2008. So far we have had 814 tornadoes across the country with the majority in the southeastern states. Normally, we should have seen just about 380 by this time. The normal average for the entire year is 1270.

Here is a graph comparing this year with recent years and with the average:

We are in the drier part of the year now but the rainy season usually begins from late May to mid June. Another event that occurs soon is the beginning of hurricane season on June 1. A tropical wave moved off of Africa yesterday. It's much too early for tropical waves to develop into depressions or storms since the water temperature in the eastern Atlantic is still too cool. But it is a reminder to be prepared for the upcoming season and have a personal plan in place. The plan doesn't have to be elaborate but just think ahead about what you would do should a tropical system threaten us this summer.

The first name on the list is Arthur and the second name is Bertha. Let's hope we do not make it all the way to Wilfred.

Normally, April is our driest month with a total of 1.8 inches of rain. So far we are slighty above normal already for the month due to yesterday's rains. Earlier this week, it almost looked like summer with regular afternoon and evening thunderstorms occurring each day. As I mentioned in an earlier blog entry, it is unusual that we have had a fairly wet winter and spring in Florida since we are in La Nina conditions. Almost without exception until now, La Nina is associated with drier than normal winters and springs in Florida.

Unfortunately, a lot of the rain events have occurred on weekends this year. The good news is that the rains are coming at regular intervals, not all at once. This allows water to soak into the aquifer more instead of just running off. Also, normally this time of year we are worried about the possibility of wild fires. So far we have been fortunate the the regular frequency of rain events has prevented any major forest firest.

What will the rest of the spring bring? Will La Nina act more normally and cause us to dry out or will we continue to get regularly spaced rain events that will help us through the fire season? Let's hope that the latter is the case. It would be better to have regularly spaced rain events in time than the ups and down with droughts and flooding.

After the official start of spring this past week on March 20, temperatures will be heading back down to winterlike values, at least for a day or two. A strong cold front for this time of year will cause temperatures to fall to slightly above freezing on Tuesday morning in inland Hernando and Citrus Counties. Even in the Bay area, mid 40's are a good bet on Tuesday morning. If we see 44 in Tampa that still won't be a record, although it will be close. The lowest temperature in Tampa on March 25 was 36 back in 1968.  There have only been 2 days in April that readings fell into the 30's in Tampa - 38 on April 6 and 7, 1891.

As I have mentioned before in an earlier blog post, the La Nina of 2008 is atypical. Usually, La Nina conditions mean a dry winter and spring for us. We continue to have cold fronts and upper level systems bringing rain every 4 to 5 days. Unfortunately, many of these systems have occurred on the weekend. Yesterday was a washout in many areas. There are signs that some more rain could return next Saturday.