Last week I wrote about how quiet it was across the tropics - not just in the Atlantic Basin but across the rest of the Northern Hemisphere as well.   There hasn’t been any further development anywhere in the world since my last update, and I’m seeing signals that at least the Atlantic Basin may remain quiet over the coming weeks.

For much of the month of June, a weak upward motion pulse has dominated the western Caribbean Sea and the East Pacific.   These pulses of upward-moving air travel around the globe, causing increasing thunderstorms and often a significant increase in tropical development for weeks at a time as they pass.   But that wasn’t the case with the current upward pulse.  Only a single named storm has developed in the East Pacific, and it appears we’ll make it through June without a named storm in the Atlantic Basin.  But what can we expect over the coming weeks?

The graphic above is a two-week prediction of areas of rising and sinking air across the tropics. Note the huge area of sinking air from the Indian Ocean through the West Pacific. In India, they’re praying for rain as the monsoon is more than three weeks late.  Only a couple of named storms have formed in the West Pacific this month in that sinking air region.  Now look at the projections for the East Pacific and the Caribbean Sea/Tropical Atlantic. The period of increased thunderstorms across this region is forecast to come to an end in a few days, replaced by an ever-expanding area of sinking air and even fewer thunderstorms by mid July.

Such a large area of sinking air, should it materialize, would certainly inhibit tropical cyclone formation in the main development region of the Atlantic Basin in July.  That’s not to say it’s a guarantee of no tropical storms or hurricanes in the entire Atlantic Basin for the next 2-4 weeks.  The area north of 20N latitude, including much of the Gulf of Mexico, may not be affected, as well as the open Atlantic north of 20N latitude.  So it’s not impossible for something to develop in the upcoming weeks, it just appears unlikely that development will occur.

I’ll continue to monitor this projection over the coming weeks and will report back on its development from time to time. Meanwhile, enjoy the tropical quiet while it lasts.

It sure is quiet across the tropics - everywhere.  The Western Pacific, which normally sees about 30 named storms per season, has had only a single named storm in June, and that one developed just yesterday.  The East Pacific hurricane season began on May 15th, and not one named storm has formed as of June 19th.  As of 1AM CDT this morning (June 19th), this is the latest start to the East Pacific hurricane season since detailed records began in 1970.

Globally, tropical cyclone activity remains at a 30-year low, similar to levels in the 1970s, and activity continues to decline.  Detailed records of global tropical cyclone intensity are sketchy at best prior to the late 1970s, so it’s hard to say just how low current activity is compared to several decades ago.  And we probably underestimated the intensity of many tropical cyclones prior to the age of modern recon, Doppler Radar and GPS dropwindsondes deployed by recon, so it’s likely that current global activity is even lower compared to the record of the 1970s.

We measure global tropical cyclone activity by the total Accumulated Cyclone Energy, or “ACE”.   ACE for a tropical cyclone is calculated by squaring the max wind speed at each 6-hour advisory interval and then dividing the end result after a cyclone dissipates by 10,000.   So ACE is a good measure of the intensity of a tropical cyclone and its duration.  The median ACE for the Atlantic Basin since 1950 is about 90.  The most active season during that period, 2005, had an ACE of 248.  The season with the lowest ACE since 1950 was 1983 with a total of only 17.    Last year’s ACE was 145, making the 2008 Atlantic Basin season a good bit above normal.  But the Atlantic Basin was the only ocean with above normal activity in 2008.  Most other regions had well below normal activity over the past 2 years.

What’s going on?  Why the big drop in ACE the past few years?   For one thing, the Earth’s climate has actually begun to cool over the past two years.  Cool La Niña conditions have prevailed across the Tropical Pacific for the past year, adding to the cooling of the climate. Cool water means less intense tropical cyclones with shorter lifespans.  The last significant cooling trend in the Earth’s climate began during the mid 1940s and continued until the late 1970s when the Atlantic began to cool considerably (cool Atlantic Multidecadal Oscillation which began in 1970 and continued through 1994).  The previous cooling began during the middle of the last warm Atlantic cycle which began in 1926 and ended in 1969. The current warm Atlantic cycle began in 1995 and will probably continue for another 10-20 years. As the Atlantic temperatures pass the peak, we should expect global climate cooling to continue in the coming years, much like the period from the late 1940s through the late 1970s.

A cooling climate is good, right?  Perhaps not.  If one checks hurricane activity across the Atlantic Basin in the 1940s, 1950s and 1960s (during the global cooling trend), this was a period of significantly increased major hurricane landfalls across the U.S., particularly from Florida northward through the Carolinas.  So cooling may not diminish the impact from hurricanes, at least not in the short term.  And as the Earth’s climate cools, farmers will experience shorter and shorter growing seasons.   For those of you concerned about global warming, I encourage you to read an article published in Newsweek on April 28, 1975:

 http://www.denisdutton.com/cooling_world.htm

There was such concern about global cooling and the potential lack of food due to the shorter growing seasons back then that some scientists advocated the questionable idea of spreading soot across the Arctic ice sheet to help melt the ice to produce global warming!  According to the article, scientists were “almost unanimous in the view that the trend will reduce agricultural productivity for the rest of the century.”   That just goes to show you how well we can predict the Earth’s climate.  I particularly liked the last sentence of the article - “The longer the planners delay, the more difficult will they find it to cope with climatic change once the results become grim reality.”   That’s something to ponder as we consider taking drastic actions to counter the predicted impact of global warming.

Given the current state of the tropics, I think that there’s a good chance that we won’t see the first named storm in the Atlantic Basin until August.  So enjoy the current lull in tropical cyclone activity while it lasts. And remember, even though we’re predicting only about 10 named storms this season, it only takes one hurricane hitting the wrong location (i.e., you) to make for a very bad year.

The 2008 hurricane season was one of the most destructive on record for both the northern Caribbean and the United States.  Rainfall from passing tropical cyclones killed over 500 people in Haiti alone last year, and Cuba was hit by three major hurricanes.  The U.S. was hit by three hurricanes, Dolly, Gustav and Ike, for a total cost of over $35 billion dollars.  The 2009 hurricane season has begun, so what can we expect this year?  Let’s examine some of the seasonal predictors to see how many storms might form, and more importantly, what regions have a better chance of being impacted this year.

El Niño/La Niña
Sea surface temperatures (SSTs) in the Tropical Pacific can provide an important clue as to how favorable the Atlantic Basin will be for tropical cyclone development.  In 2008, we witnessed a cooling of the Tropical Pacific, what we call a La Niña.  A La Niña typically results in reduced activity in the Eastern Pacific and enhanced development across the Caribbean Sea and Tropical Atlantic.  We certainly saw that in 2008. 

So what’s happening now, and what’s the forecast for the Tropical Pacific in 2009?  The graphic below identifies the trend in the Tropical Pacific SST anomaly and shows what a number of the computer models are predicting for the rest of 2009.  The “zero” line represents normal SSTs in the Pacific.  The blue dashed line represents a deviation of 0.5C below normal, which we identify as La Niña conditions.  The red dashed line represents the threshold of El Niño, which is defined as 3-5 consecutive months of SST anomalies in the Tropical Pacific of 0.5C above normal or greater.

As you can see in the image above, the SST anomaly for the Tropical Pacific is currently about 0.3C to 0.4C above normal.   The lines extending from the current time represent various forecast model predictions for what will happen the rest of the year.  The forecast is for the Tropical Pacific to warm to El Niño levels later this month and remain well above normal through 2009.  Other models are now reaching a similar conclusion that a weak to moderate El Niño will develop during the heart of the hurricane season in August and September. That’s good news, as it means that increased wind shear in the deep tropics may significantly reduce the number of named storms this season. 

The bad news is that while the Caribbean Sea and Tropical Atlantic are affected by El Niño, the Gulf of Mexico and western Atlantic off the East U.S. Coast are not impacted as much by El Niño.  This could mean that one or two tropical storms or hurricanes may form close to the U.S., perhaps in the Gulf of Mexico.  These “pop-up” hurricanes often appear with very little warning, unlike the relatively long-tracked Gustav and Ike of 2008.  So if you live along the Gulf Coast or off the southeast U.S. Coast, be prepared for a potential short-fused situation this season, a development close to the coast that doesn’t give as much warning.

Atlantic Multidecadal Oscillation (AMO)
The AMO is a a naturally-occurring cycle of warming or cooling of the Atlantic SSTs in tropics and subtropics that is related to the general ocean circulation in the basin.  I won’t go into the details of the mechanism here, but the Atlantic Ocean goes through periods in which sea surface temperatures (SSTs) are a few degrees warmer or cooler than average.  These cycles typically last from 20-40 years.  The last full warm cycle began in 1926 and ended in 1969.  The last full cool cycle began in 1970 and lasted through 1994.  Currently, the Atlantic is in the middle of another warm cycle which began in 1995.

During a warm cycle, climatology tells us that we can expect to see more intense Category 3-4-5 hurricanes (about 4 per season) than during a cool cycle (about 2 per season).  We don’t necessarily observe more named storms when the Atlantic is warmer, just that about twice as many hurricanes reach major hurricane intensity during a warm cycle than during a cool cycle. 

The good news for 2009 is that though the Atlantic Basin is in a warm cycle, the current SST anomaly is actually a little below normal.  What this means is that there is less heat energy available for hurricanes to become major hurricanes in 2009.  We might expect that rather than the 5 major hurricanes that developed in 2008, the 2009 season might have closer to 2 major hurricanes.

Analog Years
We define an analog year as one that had a similar ocean temperature pattern, a similar La Niña or El Niño pattern developing and similar steering currents to what we’re currently observing.  Our long-range meteorologist, Fred Schmude, has identified some of the analog years as 1965, 1972, 1991 and 2002.  You can see where the storms developed and where they tracked in the image below.

Probably the closest analog year to 2009 is 1965.  In the 1965 season, only 6 named storms developed.  However, one of them was Hurricane Betsy, a storm that formed north of the deep tropics where El Niño conditions prohibited development in 1965. But Betsy made its final landfall in southeast Louisiana as a Category 4 hurricane that flooded New Orleans.  This demonstrates quite clearly that just because a coming El Niño might reduce the total number of named storms in a season, it only takes one major hit to make for a very bad season.

So what are our predicted numbers for 2009?  Given that we do expect at least a weak to moderate El Niño to arrive by August/September, and that Atlantic SSTs will be closer to normal or a little below normal this season, we’re expecting close to 10 named storms, 4 of which should become hurricanes.  Of those 4 hurricanes, we think that 2 of them may become major Category 3-4-5 hurricanes in 2009.  We think that the Gulf of Mexico may see 2-3 named storms in 2009, one of which could be a hurricane. 

The analog years would suggest that as many as half of the named storms may track safely out to sea without affecting any land areas.  One region that might have a slightly increased risk of a landfall in 2009 would be Florida northward through the Southeast U.S. Coast.  Most of the analog years featured a number of hits in this region.

Finally, if you’ve been following this blog through the past season, you know that ImpactWeather has developed a new scale for estimating a tropical cyclone’s true destructive power.  We call it the Hurricane Severity Index. The Hurricane Severity Index (HSI) is a 50-point scale that assigns up to 25 points for a hurricane’s peak winds and 25 points for the size of its wind field. Last year, Hurricane Ike struck the upper Texas coast with a total HSI of 27 points, 17 of which were attributed to Ike’s great size. It was Ike’s much above normal size that produced the tremendous storm surge across the upper Texas and Louisiana coasts.

For 2009, we’re making an attempt to estimate HSI ranges for some of the more powerful storms. Here’s what we’re saying:

1 hurricane with a peak HSI of from 20-25 points
1 hurricane with a peak HSI of from 25-30 points
1 hurricane with a peak HSI of from 30-35 points

With greater wind shear across the tropics this year, we think it’s more likely that we’ll see at least one intense but compact hurricane in 2009 (30-35 points). One other major hurricane could have a peak HSI of from 25-30 points.  And one Category 1-2 hurricane could have a peak HSI of from 20-25 points.  See the link in the paragraph above for more information on our Hurricane Severity Index.

Well, that’s our prediction for the 2009 season.  We think that activity will be below normal, in terms of the total number of named storms and also with respect to the number of major hurricanes.  Look for a small concentration of impacts across Florida northward to the Carolinas, with a good number of named storms tracking harmlessly out to sea.  And watch out for a “pop-up” storm closer in to the U.S. Mainland in 2009.  Have a safe season!

ImpactWeather is forecasting a less active hurricane season in 2009, as compared to the 2008 season, however we think that there may be an elevated risk of an impact across the southeast U.S. this season.   The primary threat region will be located along the eastern Gulf coast and up the Atlantic Seaboard, especially from Florida to the Carolinas

For 2009, we’re forecasting a total of 12 named storms, 7 of which will become hurricanes and 3 of those hurricanes major hurricanes on the Saffir-Simpson scale.  However, ImpactWeather has developed a new hurricane scale that takes into account both a hurricane’s maximum sustained winds as well as the size of its wind field.  We call this new 50-point scale the Hurricane Severity Index, or HSI for short. On our scale, Ike had a total of 27 points at landfall, while Gustav made landfall with a total of 20 points out of a possible 50. This season, we are forecasting that 4 hurricanes may reach a total of 20 points on the HSI. Of those 4 hurricanes, 2 may reach an HSI value of 20-25 points, one may reach an HSI value of 26-30 points and one may reach an HSI of greater than 30 points. 

We think that at least half of all of the 2009 storms will remain in the open Atlantic, considering the Azores-Bermuda high is expected to be weaker.  This would allow for less wind shear across the Atlantic Basin and a better chance for developing storms to re-curve safely out to sea.  We are also putting a higher number of storms in the Caribbean due to above normal water temperatures just to the east of the Caribbean.  Over the Gulf of Mexico, we are predicting 3 named storms.  By far, the area of most concern will be over the Florida Peninsula where 75% of the identified storms made landfall in previous analogous seasons.  After Florida, there is a much smaller secondary maximum threat over the Texas Coast and eastern Mexican Coast from Matamoros to Veracruz.

Current sea surface temperature anomalies still indicate above-normal water temperatures throughout much of the Atlantic Basin.  Warmer than normal water typically correlates to more tropical cyclones.  In addition, there is a possibility of a weak El Niño developing over the Pacific Ocean this summer.  El Niño represents warmer than normal water (0.5C or more) over the eastern Tropical Pacific, which typically correlates to increased wind shear and less tropical activity over the Atlantic Basin.  We think there is a chance (40%) a weak El Niño will develop by the start of hurricane season, but we think there is a greater chance (60%) the El Niño will be delayed until late summer / early fall due to cold water over the eastern Pacific moving southward into the eastern Tropical Pacific.

Current Active Cycle to Continue
Prepared by:   Fred Schmude, ImpactWeather Long-Range Specialist

Ongoing analysis and projections for the upcoming Atlantic hurricane season are pointing toward another active pattern based on two key factors: water temperature anomaly profiles over the Tropical Atlantic and ENSO (El Niño Southern Oscillation) signals.  Warmer-than-normal water is directly proportional to tropical cyclone formation and development; the warmer the water in comparison to normal, the better the chance of seeing enhanced tropical development.  Also, during an El Niño phase we typically see enhanced wind shear develop over the Tropical Atlantic, which in turn will suppress tropical cyclone development. Near normal or neutral ENSO’s typically exemplify very active tropical cyclone seasons with significantly less wind shear.  A closer look at each of these indices results in our preliminary forecast for the season.

As for water temperature anomalies, preliminary data over the Tropical Atlantic indicate the water temperature pattern continues to exemplify a positive or warm Atlantic Multidecadal Oscillation (AMO) signal, with water temperatures averaging about 0.5 to 1.0C (1.0 to 2.0F) above normal in the main development region of the Tropical Atlantic.  The Caribbean and Gulf of Mexico are trending near or slightly above normal.  In comparison to last year, temperatures are running a little higher this year over the Tropical Atlantic, and at about the same level for the Caribbean and Gulf.  We see no reason why this trend will not continue into the summer and fall of 2009 with warm AMO conditions continuing, leading to above normal water temperatures over much of the Tropical Atlantic during 2009.

Concerning the latest ENSO forecast for the upcoming spring and summer, we are seeing a pattern similar to 2008.   Last year the trend was from a moderate to strong La Niña over the Tropical Pacific to a near normal or neutral stage during the summer and fall months.  This year we are again in the midst of another La Niña.  Even though this La Niña is currently weaker than it was last spring, it still shows remarkable similarities to last year.  Detailed analysis of Pacific water temperature profiles down to several hundred feet and long-range computer model forecasts all indicate this La Niña will gradually transition to neutral phase as we move into the spring and summer, very similar to last year.  Already we are seeing signs of a weakening trend and we see no reason why this will not continue.  In recent weeks, some long-range models have begun to indicate that water temperatures in the Tropical Pacific may continue to warm into the peak hurricane months of August and September, perhaps even to weak El Niño levels.   Should such warming actually reach weak El Niño levels, then we might expect this to be a factor that would reduce the number of named storms in 2009.  But these long-range forecasts are notoriously bad, and the current long-range forecast appears to show too rapid of a warm-up in the Tropical Pacific this spring.

Initial forecast for the 2009 season:   Above normal water temperatures over the Atlantic Basin combined with a near neutral ENSO forecast for the upcoming summer and fall point toward a potentially active season with an excellent chance (80%) of reaching the average number of named storms (12) and a good chance (50%) of seeing an above normal number.  Our initial projection is for 13 to 17 named tropical cyclones, of which 7-9 will be hurricanes and 3-5 major hurricanes.

It’s pretty clear that the 2008 hurricane season is over.  Temperatures this Friday morning along the Louisiana coast and eastward are in the low 40s and dropping behind a fairly strong cold front.  I’d mentioned this front last week, so this is no big surprise. The front will produce northerly winds of 25-35 kts (with higher gusts) today and tonight across the northwest Gulf lease areas.  Winds and seas will diminish over the weekend.   Freezing temperatures may be experienced from south Louisiana eastward through the Florida Panhandle on Saturday morning.

Though there will be no further tropical threats to the Gulf this year, I do see a potential stormy period for the northern Gulf late this month into early December.  Details are not clear yet, but I’m seeing strong indications of a storm system tracking across the Gulf Coast late this month, perhaps between the 28th-30th. The storm center should remain inland, but it could result in strong southerly winds late next week followed by a line of heavy squalls and strong wind gusts as the system moves eastward along the Gulf Coast.  This is a common fall pattern, but it’s a change from recent weeks.

In the very long range, we’re seeing a developing pattern that’s much like December of 1983 and 1989 across northwest Canada and Alaska.  In case you don’t remember, the Gulf Coast was hit by several very cold Arctic fronts in those years, dropping temperatures to the low teens (and lower) down to the Gulf Coast. It’s definitely quite a bit colder than normal across Alaska and northwest Canada right now, so we’ll have to watch out for southward push of some frigid Arctic air around the second or third week of December.  Such fronts can produce very strong winds offshore, along with quite cold temperatures.  In 1983, for example, the air was so cold that snow flurries were seen on offshore rigs off the upper Texas and Louisiana coasts.  I’m not predicting snow offshore, of course, but I do think some very cold air may impact the Gulf toward mid December.

There are officially only 16 more days left to the 2008 hurricane season, but it appears unlikely that we’ll see another named storm this year.  Certainly, the Gulf of Mexico has shut down as far as any tropical threat.  Strong wind shear has prevailed across the Gulf for several weeks, and that shear will be increasing as the weather pattern across the U.S. changes to one resembling winter rather than fall.

Long-range models continue to forecast a southward dip in the jet stream over the coming week, bringing a series of very cold Canadian fronts southward to the Gulf of Mexico.  The first of these fronts arrives tonight.  These early-season cold fronts can produce quite strong winds offshore.   When cold air blows across the still very warm Gulf of Mexico, the wind can accelerate to speeds greater than tropical storm force with gusts approaching hurricane force.  Tonight’s front won’t produce hurricane force wind gusts, most likely, but it should produce wind speeds offshore above tropical storm force on Saturday.

Many years ago, I learned of a general rule of thumb to predict how strong the winds will get across the northwest Gulf following a frontal passage.   The key is to look at the high pressure center behind the front.    Air pressure can be measured in inches of mercury or millibars.  I know that the more meteorologically-correct term now is “hectopascals”, but I’ll never be converted.  To estimate how strong the sustained winds will be offshore, look at the strength of the high pressure behind the front.  If it’s, say, 1045 millibars, then just remove the 10 from the front and the wind offshore will approach 45 kts.  This method actually works quite well, particularly with these early-season fronts.

With tonight’s front, the high pressure behind it will be 1029-1033 millibars,so we should expect winds offshore in the 30 knot range on Saturday, with gusts as high as 40-45 knots.  Along the east coast of Mexico down to the Bay of Campeche, the winds will be even stronger than that, as the wind tends to accelerate southward along the coast of Mexico.  The blast of cool air and rough seas won’t last long  By Sunday morning, the high center will push out into the Gulf and wind and seas will quiet down quite quickly.

In the long range, both the American GFS model and the European (ECMWF) model have been forecasting a major pattern change across the U.S. which could bring some very cold air southward to the Gulf of Mexico as early as next weekend, around the 21-23 of November.  However, I’m seeing way too much variability from one model run to another to have much confidence in the timing of any big cold air push across the Gulf a week or more from now.   But there is some very, very cold air building in northwest Canada and Alaska now.  At some point over the next 2-3 weeks I do expect some of this cold air to break loose and race southward toward the Gulf.  Such a cold front could produce winds offshore to 40-50 knots, along with very rough seas.

So it’s time to stop looking to the south for the rough weather across the Gulf.  The rough weather will be coming from the north from here on out.

As I mentioned last week “Those of you in south Florida, breathe half a sigh of relief for now.  I’m still keeping my eye on that southwest Caribbean Sea.  We still need to monitor that area for possible development for another few weeks.  Anything developing down there still has a chance of impacting south Florida.“   Well, earlier this week, an area of thunderstorms in the southwest Caribbean Sea developed into Tropical Depression Seventeen, which has now become Hurricane Paloma, the sixteenth hurricane of the 2008 season.

Fortunately for those of us in the U.S., Paloma won’t be any threat.  Cold fronts are moving regularly across the Gulf of Mexico now, far enough south to protect even south Florida from Paloma’s effects.   But it’s going to be a rough next 36 hours across the Cayman Islands, as Paloma will very likely be a major Category 3 hurricane with 115-120 mph winds as it moves right across Grand Cayman Island tonight.  As of noon local time Friday, Grand Cayman Island was reporting winds of 35 mph gusting 45 mph as Paloma’s outer bands move across the island.

Beyond tonight, Paloma will start feeling the influence of that approaching cold front, resulting in a turn to the northeast and inland across eastern Cuba Saturday night/Sunday morning.  Models disagree somewhat on Paloma’s fate beyond Sunday.  One camp accelerates a weakening Paloma out to sea to the northeast.  The other group of models dissipates Paloma near the Bahamas and can’t figure out what to do with Paloma’s remnant low.  Either way, I think it’s unlikely that Paloma would survive as a hurricane to impact the Bahamas after crossing Cuba.  It could produce tropical storm conditions across the central to eastern Bahamas and Turks & Caicos Islands late Sunday and Monday, though.

What about the rest of the season?  There are only 3 more weeks left to the 2008 hurricane season, officially.  While I don’t see any more disturbances moving off the west coast of Africa that might track into the Caribbean Sea, long-range models continue to indicate increased thunderstorms across the southwest Caribbean.  This is particularly true after about the 16th of November when another cold front pulls up stationary in the southwest Caribbean. 

It’s possible another storm may develop in the southwest Caribbean the third or fourth week of November.  However, chances of it impacting the northwest Gulf are close to zero.  Even south Florida should be in the clear by then.  With any luck, Paloma will mark the end of the 2008 hurricane season.

I still do plan to write an end-of-season wrap up here.  But with Paloma still out there and the possible development of one more storm, I think I’ll wait another couple of weeks.

Today is the last day of October and I think that it is looking more and more like the 2008 hurricane season has come to an end.  Over the past week, a strong cold front pushed all the way across the Gulf of Mexico and into the Caribbean Sea, bringing record low temperatures to the southeast U.S. including Florida.  Wind shear is increasing all across the Tropics now, and tropical disturbances are few and far between.

The season totals stand at 15 named storms, 7 of those hurricanes and 4 of those 7 major hurricanes.  It’s been an active year as far as land falling storms.  There was a period of 6 consecutive land falling storms across the U.S. - from Dolly through Ike.  Three  Category 2 hurricanes made landfall on the U.S. Mainland this season - Dolly, Gustav and Ike, causing over $50 billion in damage and considerable loss of life.   There was a tremendous impact across Haiti and the Dominican Republic this season, leaving over 1000 people dead from flooding.    With the coming of November, I think that most areas can breathe a collective sigh of relief.

Those of you in south Florida, breathe half a sigh of relief for now.  I’m still keeping my eye on that southwest Caribbean Sea.  We still need to monitor that area for possible development for another few weeks.  Anything developing down there still has a chance of impacting south Florida.

I’ll be preparing a bit of a summary of the season for next week’s post.

As I mentioned last week, hurricane activity typically drops off fast after the second to third week of October.  As I write this post early Friday morning, the temperature is in the mid 40s in southeast Texas behind a rather strong cold front that’s moved out across the Gulf of Mexico.   Westerly winds of between 70 and 100 mph are blowing across the Gulf of Mexico in the upper levels now.  Strong upper-level winds mean strong wind shear across the Gulf, and wind shear is the bane of hurricanes.  Long-range models indicate that this jet stream will remain well to the south across the Gulf of Mexico through next week at the very least.  With such flow in place, it would be impossible for the northwest Gulf to be hit by another hurricane.  So let’s just hope that jet stream remains well to the south for another few weeks.

But I’m not ready to declare with certainty that the 2008 season has ended for all locations.  There will be pockets of lower wind shear that pop up from time to time farther to the south across the southwest Caribbean Sea.    Very long-range models are forecasting an increase in thunderstorm activity in the western and southwestern Caribbean Sea during the first and second weeks of November.  So it is possible that another named storm could develop there this season.  Most, if not all, late-season storms that form in the western Caribbean Sea take a track either inland into Mexico or Central America or to the northeast across Cuba, perhaps affecting south Florida and/or the Bahamas before heading out to sea.   I don’t think that any such late-season development would likely threaten the northwest Gulf of Mexico.