Atlantic Sat Image

Atlantic Sat Image
Clouds over Atlantic

Thursday, October 14, 2010

Sneak Peak

We dodged another bullet with "Paula" weakening and only impacting us slightly with some pockets of rain mainly across the Keys. Central and western Cuba received anywhere between 6-8 inches of rain with isolated spots reporting around 10. But all is not done.

It seems one model is hinting at another system brewing in the Caribbean over the next few days. It will develop in the Central Caribbean in about 120 hours and make a move towards Central Cuba. Let's see if this model pans out.

Check out the link below for the latest model run. Hit forward on the right side of the screen and wait until it runs through 120 hours of data.

Tuesday, October 12, 2010

Paula Power

It appears Paula may be one of the fastest growing storms on record reaching hurricane status in a mere 12 hours. The first advisory was issued on Monday at 5 pm and by Tuesday morning at 5 am it was upgraded to a Category one system. NHC began recording this type of data about 40 years ago and in all that time no system had grown this fast. The closest before was 18 hours with Hurricane Humberto in 2007.

I said it appears Paula managed this feat, that's because by the time the first advisory was issued, NHC had classified it as a tropical storm by-passing depression status all together. Maybe at the end of the hurricane season when NHC looks back at the data, they may include this extra time period and bump it from the top spot. If this happens, it will tie Humberto for fastest intensification.

The big question is where is it headed. Models all agree that a cold front will move into the Gulf over the next few days and push Paula East. Plenty of shear ahead of the front may weaken it as it moves towards Western Cuba.

Five days out models disagree as to what will happen, with some dipping Paula back South into the Western Caribbean, others push it across Cuba, while others take it to the Florida straits. Strength is also an issue. Models hint at a weaker system in 5 days, but it if sits over water for too long, it just may hold on to hurricane status.

Keep watching.

Wednesday, October 6, 2010

Sub Tropical What?

A sub tropical system basically means we have a hybrid storm. It looks like a normal area of low pressure that moves throughout the natiion's midsection, but acts like a warm core tropical low. Its a category for those storms that quite don't fit the typical definition of a Tropical Cyclone.

Here's how NHC defines it:

A sub-tropical cyclone is a low-pressure system existing in the tropical or subtropical latitudes (anywhere from the equator to about 50°N) that has characteristics of both tropical cyclones and mid-latitude (or extratropical) cyclones. Therefore, many of these cyclones exist in a weak to moderate horizontal temperature gradient region (like mid-latitude cyclones), but also receive much of their energy from convective clouds (like tropical cyclones). Often, these storms have a radius of maximum winds which is farther out (on the order of 100-200 km [60-125 miles] from the center) than what is observed for purely "tropical" systems. Additionally, the maximum sustained winds for sub-tropical cyclones have not been observed to be stronger than about 33 m/s (64 kts, 74 mph)).

Many times these subtropical storms transform into true tropical cyclones. A recent example is the Atlantic basin's Hurricane Florence in November 1994 which began as a subtropical cyclone before becoming fully tropical. Note there has been at least one occurrence of tropical cyclones transforming into a subtropical storm (e.g. Atlantic basin storm 8 in 1973).

Subtropical cyclones in the Atlantic basin are classified by the maximum sustained surface winds:

less than 18 m/s (34 kts, 39 mph) - "subtropical depression",
greater than or equal to 18 m/s (34 kts, 39 mph) - "subtropical storm"
Prior to 2002 subtropical storms were not given names, but the Tropical Prediction Center issued forecasts and warnings on them similar to those for tropical cyclones. Since 2003 they are given names from the tropical cyclone list.
For more information see Penn State University's write up on the Subtropical Cyclones.

Tuesday, September 28, 2010

Tropical Rain

As of Tuesday morning the area of disturbed weather in the Caribbean Sea has been classified as Tropical Depression 16. A recon plane will investigate the area later today. The models show it tracking towards us. The plane will get a better handle on its intensity and future growth. It appears that by this afternoon it will become a Tropical Storm.

As of 11 am, all of Southeast Florida is under a Tropical Storm watch.

The system will come for us. We won't have to chase it. It should track up the Florida Keys into Miami Dade, Broward, and exiting Palm Beach .

Models here:

This system has so much rain with it that South Florida could see a generous soaking starting this afternoon. Already we've seen isolated pockets of t-storms throughout the area. NWS has issued a Flood Watch for this afternoon. Between Tuesday and Wednesday we could see 4-8 inches of rain with pockets of more.

The Caribbean has become a tropical system nursery. Long range models show yet another disturbance brewing by Friday.

Sunday, September 26, 2010

Yet another worry?

Ever since "Matthew" developed last week, most long range models were also suggesting another area of low pressure would develop in the Caribbean Sea. This is worrisome because the favored track for systems developing here is to move either straight towards Florida or move into the Gulf and then head to Florida.

Even if the steering winds keep it away from us, they could push the low across Central America causing large amounts of rain that could lead to devastating floods, land and mud slides.

As I have mentioned in the past, so far this year it appears that the CMC model has been performing the best. It too now shows something developing in the Caribbean Sea and aiming for us. Check out the link below for the latest CMC run. Once its loaded hit the forward button. It goes out 120 hours. It may take you a moment or two to see the swirl developing south of Cuba and then heading for the Sunshine State.

NHC is now confirming the possibility of that happening. They are giving the area of clouds and rain sitting over the Western Caribbean Sea a 10% chance of becoming a depression in the next few days.

This would be a good time to check your preparedness plan just in case. If the CMC does pan out, we may be dealing with a system here towards the end of the incoming week. I hope it's wrong.

Friday, September 24, 2010

"A low confidence forecast"

That is the sentiment coming from the National Hurricane Center on Friday morning regarding "Matthew". It appears the system has many factors influencing its future path, and to be quiet honest, the models don't have a good handle on them.

Let's focus on what we know: There is some light shear impacting Matthew and this should keep it in check for another 48 hours. High pressure to the north will push Matthew towards Central America until Sunday, after that, all bets are off.

The UKMET model pushes 'Matthew" into the Western Gulf of Mexico in about 5 days. If this happens, Matthew has to travel over allot of terrain that could significantly weaken it or dissipate it all together. Meanwhile the GFDL, HWRF, and GFS ensemble models turn it to the Eastern Gulf. In this scenario it will have a chance to grow stronger.

Why the discrepancies? Believe it or not, a Monsoon Low is developing over Central America that may drag Matthew into the Western Gulf. There is a front pushing out of Texas as well over the next few days that may shove Matthew to the Eastern Gulf. This is why the cone of uncertainty is so wide by the 5th day. It tries to compromise the wide array of tracks into one.

Worst case scenario for us would be a turn into the Eastern Gulf of Mexico which could potentially spell an impact for Florida by the end of next week.

In the words of the National Hurricane Center: "Significant changes (to the forecast cone) may be required later today" I'll keep you posted.

Monday, August 30, 2010

Hurricane Models like Athletes?

Many questions have arisen regarding the potential track of Earl and rightfully so. We all remember Hurricane Andrew with a similar track in 1992 and Hurricane Charlie in 2004. Charlie was expected to hit Tampa , but at the last minute changed course making landfall father South near Punta Gorda.

I have received countless e-mails, calls and texts regarding this question... "are you sure Earl wont hit us?" The truthful answer is no. Nothing is ever certain.

We rely heavily on highly complex and specialized computer models. Their forecasts are as good as the information given to them. Many, like athletes go on streaks. Some models will nail down every forecast one year, and fail miserably the next. Its up to us to figure out which one is at the top of its game. This year, in my opinion, it's the CMC.

I have been following the CMC model since the beginning of the hurricane season, and thus far, it is performing the best. Accurately forecasting all the tracks ( even the loop that TD 5 made over the Southeast ) and possible landfall sites.

It has been showing Earl getting pushed along to the west by the Bermuda high and then at the same time, a trough ( a weak front, accompanied by an elongated area of low pressure ) moving off the Atlantic seaboard. This traps Earl and sends it to the north becoming a worry for the middle Atlantic states down the road.

Check out the CMC model run on this link:

Everything in blue are areas of low pressure, in orange high pressure. You will find Earl as a tight circle east of Puerto Rico. On the right hand of the page (on some it may be way at the bottom) click on fwd and see the animation take Earl to the East Coast of the USA.

Because the CMC has been accurate so far, I feel confident in its track. Still, models like athletes, can have an unexpected injury or slump so keep monitoring is track just in case mother nature throws us a curve ball.

Thursday, August 19, 2010

Get a Grip!

NASA is really getting into hurricanes! Within the next few months they will deploy a handful of planes to study how hurricanes form and why they grow in strength so rapidly. The program is called GRIP. G for Genesis (relating to the beginning or birth of hurricanes) R for rapid, I-intensification and P for process.

The research will take place over the peak of hurricane season between August and September. It is hoped that the data will help forecasters determine the recipe for hurricanes, and that it will provide the keys for determining how and why they grow in strength.

The research will take months, but it will be worth it for all of us.

Link to the site below for a small video from NASA regarding GRIP.

Tuesday, August 17, 2010

Quiet Cape Verde, so far....

Hurricane season began June first and runs through the end of November. This of course is a man made timeline as storms can brew at any time of year as long as there is sufficient energy.

The primary source of fuel for hurricanes is warm ocean water of at least 80 degrees. Obviously the span from June through November is when the sea surface temps are the warmest and thus this is our hurricane season.

Hidden within this season is a smaller and more active grouping of months known as Cape Verde Season, usually kicking off around August and coming to an end by October. It is so called, because hot pockets of air come off the West Coast of Africa, move over the Cape Verde Islands, and then if the conditions are right, can grow into hurricanes. They move over the entire Atlantic picking up plenty of energy turning many of these Cape Verde Systems into monsters.

One great example was hurricane Andrew in 1992.

If we narrow our focus, we can see that activity picks up in August and reaches its peak in September. This search shows the amount of tropical systems sprouting between 1851 and 2009. In AUGUST there is a total of 352 systems while in SEPTEMBER it skyrockets to 540.

Experts are still predicting an active 2010 with around 20 tropical storms , above the seasonal average of 11. So far we've only seen Alex, Bonnie, and Colin. Up to this point it has been a rather dull and quiet season. Why? A few items come to mind. A strong Bermuda high, an expansive SAL or African dust plume in the atmosphere, and an unimpressive La Nina event.

Top scientist still warn that La Nina will rear its head soon making conditions better for hurricanes to grow, so we must remain vigilant. Some long range models, specifically the CMC has been on the mark this year forecasting activity and its calling for something to develop off the Cape Verde islands within the week. Hopefully it will be wrong. I would hate for our uneventful season so far, to come to an end.

Sunday, August 1, 2010

Why we should watch INVEST 91

A wave that came off Africa on Saturday has already developed a low pressure center of circulation. It appears it will not meet the same fate that a previous wave did on Saturday. Late last week a vigorous wave pushed into the eastern Atlantic, only to be choked by dry air, suffocated by African dust and squeezed by this new wave.

This new low , known as INVEST 91, will stay South of all that hostile activity steering over warm ocean waters with very little shear ahead of it. Most models intensify the low taking it near the Lesser Antilles as a Tropical Storm in 5 days. If it does grow into a storm, it will be called "Colin".

The models are pretty much in agreement over its future path, but not so much in its intensity. This worries me a little more than usual and here is the reason why. It may travel through the "Hebert Box". What in darnations is that?

This Box was named after Paul Hebert, once a director of the local National Weather Service office, and former forcaster for the National Hurricane Center. I was fortunate to be proctored by him during my early Weatherman days in the 19... lets say a while ago.

His research of past hurricane tracks lead him to a theory that says: Nearly every Major Hurricane that has hit South Florida since the start of the 20th century went through these boxes.

The boxes are located in the Atlantic and Caribbean. The first box is found east of Puerto Rico and the second box is located over the Cayman Islands. He adds that storms don't have to go through the boxes to hit us but if they do you have to watch out.

The pattern has proven accurate for 9 out of 10 storms that developed & hit Dade,Broward & Palm Bch Counties.

Now compare Box 1 with the latest model runs regarding INVEST 91... it just makes you wonder.
So what does this all mean? Right now nothing. But it is worth watching as INVEST 91 makes its way closer to the Hebert Boxes.

Sunday, July 25, 2010

Why so Quiet?

So far we have had two systems in the Atlantic basin, a hurricane impacting Mexico and Texas and the most recent "Tropical Storm Bonnie" crossing South Florida with some squally weather and rough seas. Up to this moment it is still a quiet season, at least for the mainland, So why so quiet?

We, at the weather office have been noticing how strong the Bermuda high has been so far, digging far South in the Atlantic and its most western edge almost into the Gulf of Mexico. While this system typically pushes tropical activity our way, it is acting more like a huge shield protecting us.

There is also SAL (the Saharan Air Layer) keeping the mid to upper levels of the atmosphere rather dry and making it almost impossible for thunderstorms to form, organize and grow into hurricanes. This Saharan dust is caused by huge windstorms over AFrica, that whip the sand into the mid atmosphere where it is pushed along by strong winds. During its long ride, that can take it all the way to the North American continent, it curbs any and all activity.

As long as these two items remain in place... we may see a hopefully average tropical season of around 10 named storms out of which 6 may become hurricanes, and out of that number maybe two turn into Category threes or above.

Keep your fingers crossed,