[OFFICIAL] Hurricane Season 2007

[Jeff]

Since we were having a little discussion related to hurricanes in another thread, I thought I'd start a new one here that allows us to keep up with the storm season. As I mentioned there, the six week period between August 1 and September 15 is peak season for hurricanes.

In Texas, the most dangerous time is between August 15 and September 7. After September 7, our chances decrease each day until September 15 when they start to drop like a rock. Only one major hurricane (Rita) hit the Texas coastline after September 15 and that was in a very weird year.

The latest today...

Tropical Storm Chantal is rapidly moving north in the Atlantic and is no threat to intensify or hit land.

However, the disturbance listed as Invest 99L by the National Hurricane Center is interesting. It weakened a bit today as it came into contact with dry air, but at least two of the computer models are predicting it will become a tropical depression within the next couple of days. One has it reaching tropical storm strength and the official intensity forecast has it at a cat 1 hurricane after 120 hours.

Right now, it is moving west and if it doesn't gain any northerly motion over the next couple days, those most likely to be effected are folks along the Central American coastline. A fairly significant ridge of high pressure is moving into the midwestern US behind a front that will bring us some rain Thursday and Friday. That ridge will likely make it difficult for this storm to make any kind of northerly turns.

Definitely one to keep an eye on.

[rrj_gamz]

Well, this causes volatility in the gas/electric markets, so this could make a bad summer great...

[GuerillaBlack]

Man, hasn't it rained enough? And the two hurricane seasons after the 2005 fiasco have been quiet.

[Jeff]

Originally Posted by GuerillaBlack Man, hasn't it rained enough? And the two hurricane seasons after the 2005 fiasco have been quiet.

Last year was an El Nino year, which limited storm formation and allowed a lot of storms to stay harmlessly out to sea.

This year has been quiet so far, but there have been seasons where the first named storm didn't occur before August 1 and there were still 15 named storms and half a dozen or more hurricanes.

I don't think we'll have 15 named storms this year. But, this is the time of the biggest storms and most serious hurricanes. Fortunately, conditions haven't been super favorable so far for any kind of significant development, but that is changing.

I was checking out Jeff Masters' Wunderblog and his fill in (he's on vacation) wrote that 99L probably won't develop until it is in the western Caribbean or, more likely, until it passes over Central America and emerges in the eastern Pacific.

[OrangeCounty,CA]

Jeff, i thought historically, the active segment of the Hurricane season actually is all of august, september and october, with septeber 15th being the peak! Maybe you meant the peak for hurricane activity in Texas was from august 1 to september 15.

So the the computer models do indeed have the low pressure area east of the winward islands developing after all...

[Jeff]

Originally Posted by OrangeCounty,CA Jeff, i thought historically, the active segment of the Hurricane season actually is all of august, september and october, with septeber 15th being the peak! Maybe you meant the peak for hurricane activity in Texas was from august 1 to september 15. So the the computer models do indeed have the low pressure area east of the winward islands developing after all...

Correct. I did mean Texas.

A couple of the models do have it developing. The others don't. The problem for that storm is not just the dry air, but also the effect of the northern coast of South America and unfavorable conditions for the next couple of days. Plus, if it continues to move west over the next day or two, it is going to be tough for it to get any northward motion at all. The GFDL has it hitting the Central American coastline in about 4 days as barely a tropical storm.

[coma]

I saw a snippet on the news the other morning where they mentioned the past 5-6 times we've had record July rainfall, it was always followed by a catastrophic hurricane.

The first one was the hurricane that blasted Galveston and the other notable one was the one that slammed Port Lavaca/Indianola. So far in July we've recieved 9+ inches of rainfall.

I watch all these reports that yes, it's going to rain (well NFS), but I've yet to see a report on why this year is so crazy with the rainfall.

Edit: So I just had to look it up, and found this as Jeff's aforementioned website:

http://www.wunderground.com/blog/190...cane/show.html

[KingCheetah]

There is no such thing as hurricanes.

[Jeff]

Originally Posted by coma I saw a snippet on the news the other morning where they mentioned the past 5-6 times we've had record July rainfall, it was always followed by a catastrophic hurricane.

Technically that article says that increased amounts of rainfall in July mean a higher likelihood of an upper Texas coast strike of any tropical storm, not just a catastrophic hurricane. Really, when you say "catastrophic," it equals "major" (i.e. cat 3 or better) and only 3 major hurricanes hit the upper Texas coast in the linked analysis.

This doesn't mean it isn't good data or interesting. It's both. But, it doesn't necessarily mean we will get a major hurricane in the Houston/Galveston area this year.

I would say it is far more likely we see a tropical storm or depression than a hurricane. And, other than the storm of 1900, Tropical Storm Allison is still, by FAR, the worst natural disaster to hit the Houston area.

[Jeff]

Just an update...

Invest 99L hasn't changed and only one model develops it into a tropical storm before hitting the northern Central American coastline. All other models have it dissipating and even the NHC doesn't sound confident at this point.

Only one long-range model has any activity in the Atlantic Basin over the next 5 days and it's minor. Hopefully, we'll have a quiet week.

[Jeff]

This will likely only be of interest to the nerdiest of you weather nerds, but I thought this was interesting.

NOAA has a Tropical Heat Potential page on their site that displays how warm the oceans are and how deep that warm water is. Hurricanes need not only warm Sea Surface Temperatures (SST's), but they also need that warm water to extend pretty deep into the ocean for them to blow up into large hurricanes.

Both Katrina and Rita exploded overnight thanks to a phenomena knows as the Gulf Loop Current - a current of warm water that spawns a small eddy or pool of very warm water in the central to northern Gulf every 8 months or so. In 2005, that particular eddy was fairly deep and VERY warm. Here's an image from NOAA from August of 2005.



Note that big blob of red dead center of the Gulf. That's what did it.

Now, by contrast, here was July 11, 2007:



The eddy is MUCH smaller, but note how warm the northern Caribbean is. That was really surprising given how early in the year it was at that time. Now, here is that image from yesterday:



The Gulf and northern Caribbean has actually gotten COOLER since July 11, which is great for us.

However, the depth of the warm water in the Gulf has increased since early July, which is to be expected, but the smaller eddy and the cooler temperatures bode well for us given the time of year. No doubt, it will get warmer over the next month, but this is an encouraging sign at least when it comes to the potential for a big mutha of a hurricane in the Gulf.

[MadMax]

wow, that is good news. thanks, jeff.

[rocketsjudoka]

Very interesting stuff Jeff and the other weather nerds keep the info coming.

[Behad]

Originally Posted by Jeff This will likely only be of interest to the nerdiest of you weather nerds, but I thought this was interesting.

This is my wife's "weather favorites" folder:
http://www.wildonweather.com/forum/private.php?
http://wwwa.accuweather.com/index-fo...code=77573&u=1
http://www.crownweather.com/tropical.html
http://www.wunderground.com/
http://www.weather.com/weather/my
http://orca.rsmas.miami.edu/wximages/jet/1_05/anis.html
http://www.skeetobiteweather.com/index.asp
http://hurricane.methaz.org/hurapak/#AAL182005
http://myweb.cableone.net/nolasue/houcat4.gif
http://www.nhc.noaa.gov/HAW2/english...sk_areas.shtml
http://www.nhc.noaa.gov/
http://www.sfwmd.gov/site/index.php?id=8
http://www.srh.noaa.gov/ifps/MapClic....x=53&map.y=89
http://www.hardcoreweather.com/
http://www.ssd.noaa.gov/goes/east/gmex.html
http://www.meteo.psu.edu/~gadomski/ewall.html
http://www.easternuswx.com/bb/index.php?act=home
http://www.weather.gov/
http://www.khou.com/images/weather/radars/hou_metro/
http://www.wunderground.com/
http://www.intellicast.com/IcastPage...=none&pid=none
http://www.intellicast.com/IcastPage...p&prodnav=none
http://www.weather.com/outlook/recre...hr_topnav_golf

Yeah, she fits the description....

[LonghornFan]

Originally Posted by coma http://www.wunderground.com/blog/190...cane/show.html

After reading that I came to this post;

Earlier, I did a blog on the potental of a Hurricane Striking the Houston/Galveston area and the potental damages that is posessed, as well as a worst case senerio for the city.

Anyone have a link for that blog entry?

[Jeff]

Originally Posted by LonghornFan Anyone have a link for that blog entry?

http://www.wunderground.com/blog/190...&tstamp=200704

It's similar to the doomsday scenario story the Chron has run a couple times. If a cat 4 or 5 storm were to come up from the south through the ship channel and into Houston, yeah, it could get ugly.

But, the chances of that happening are so incredibly slim, I couldn't even calculate them. The storm would not only have to be a big cat 4 or cat 5 storm, but it would have to travel on a VERY specific trajectory. We saw how one tiny little nudge turned Katrina from a direct hit on New Orleans to a glancing blow.

It is a dangerous scenario, but the odds are astronomical.

[Faos]

http://chron.com/disp/story.mpl/front/5024714.html

Hurricane expert cuts forecast to 8, 4 intense


Associated Press

Hurricane researcher William Gray lowered his 2007 forecast slightly today, calling for 15 named storms, with eight becoming hurricanes and four becoming intense.

On May 31, at the outset of hurricane season, Gray had called for 17 named storms and nine hurricanes, five of them intense.

"We've lowered our forecast from our May predictions because of slightly less favorable conditions in the tropical Atlantic," said Philip Klotzbach, a member of Gray's team at Colorado State University.

The new forecast calls for three named storms, two hurricanes and one intense hurricane in August; five named storms, four hurricanes and two intense hurricanes in September; and five named storms, two hurricanes and one intense hurricane in October and November combined.

The Atlantic hurricane season, which runs from June 1 to Nov. 30, averages 9.6 named storms, 5.9 hurricanes and 2.3 intense hurricanes per year.

Despite the reduction, Gray said, the activity called for in the new forecast is still 60 percent more than the long-term average.

There were 10 named Atlantic storms last year and five hurricanes, two of them major. None of the hurricanes hit the U.S. coast.

The latest forecast put the chances of an intense hurricane hitting the U.S. coastline at 68 percent for the rest of this season.

Chances of an intense hurricane hitting the East Coast, including the Florida Peninsula, are 43 percent, Gray said. For the Gulf Coast from the Florida Panhandle to Brownsville, Texas, the probability is 44 percent.

The forecast also called for above-average risk of a major hurricane making landfall in the Caribbean.

The devastating 2005 season set a record with 28 named storms, 15 of them hurricanes. Four hurricanes hit the U.S., including Katrina, which devastated parts of the Gulf Coast.

[Jeff]

No shock in the numbers or the reduction. Though, it looks like it will be a quiet first couple weeks of August given the forecast.

[solid]

I have been a weather nerd since childhood. I definitely keep up with hurricane season; Rita took out 62 trees. Three of them hit my house. I am still trying to get back to pre-Rita. The crazy thing is that I am over 200 miles inland. I grew up in the Galveston area, and if Rita or Katrina had hit the island, I hate to even think about it. The cool water in the Gulf looks good to me.

[Jeff]

http://www.chron.com/disp/story.mpl/front/5040188.html

Forecasters now predict 16 storms, 9 hurricanes

MIAMI — Government forecasters minimally reduced their prediction for the Atlantic hurricane season today, but said that up to nine hurricanes and up to 16 tropical storms are expected to form, still a busier-than-average season.

The National Oceanic and Atmospheric Administration maintained its estimate that three to five of the hurricanes will be major storms of Category 3 strength or stronger. The original report forecast up to 17 tropical storms, with up to 10 becoming hurricanes.

Despite the slight reductions, NOAA said atmospheric and oceanic conditions mean that the season likely will be more active than normal. On average, there are 10 named Atlantic storms and six hurricanes, three of them major.

Federal forecasters' move today follows that of Colorado State University hurricane researcher William Gray, who slightly lowered his forecast last week.

Gray's initial projection called for 17 named storms and nine hurricanes, five of them intense. He revised it to 15 named storms and eight hurricanes, four of them intense.

After the battering by storms Katrina and Rita in 2005, there were widespread fears last summer of another powerful storm striking. But the unexpected development of El Nino — the periodic warming of Pacific Ocean waters that affects wind patterns and tends to result in fewer Atlantic storms — helped dampen conditions.

No destructive storms hit the U.S. last year, but forecasters warned this year that El Nino is over, which could prompt conditions that encourage the development of additional storms.

The season has been tame so far, but August typically marks the start of the most frenetic months of Atlantic weather.

Just as federal forecasters announced their initial seasonal projections in late May, Subtropical Storm Andrea developed about 150 miles northeast of Daytona Beach. The storm skirted the southern Atlantic coast but caused minimal damage.

Tropical Storm Barry formed on June 1, the first official day of hurricane season, and brought needed rain to drought-parched Florida.

Last year, there were 10 tropical storms in the Atlantic and just two made landfall in the United States.