Friday, September 30, 2011

2 in the Atlantic

HURRICANE "OPHELIA"

Ophelia is a well organized hurricane aiming for Bermuda. Our friends there need to watch this one carefully as it could get a little stronger as it nears the island over the weekend.


This image clearly shows an eye with a well organized eyewall.

This is where you'll find the strongest winds and heaviest rainfall. It is a ring of destruction.

It should pass to your east, but none the less, you will feel Ophelia's fury.

Following is the official forecast cone for Ophelia.




TROPICAL STORM "PHILIPPE"

Tropical Storm Philippe is in the Eastern Atlantic and holding its own. The National Hurricane Center said it best.

THE RECENT EVOLUTION OF PHILIPPE IS A BIT OF A MYSTERY. 

This is why I love weather, just when you think you have things figured out, Mother Nature says "Oh no, I have plenty of secrets left!"


Here is what's interesting about Philippe:

  • NHC SAYS: A RECENT SATELLITE IMAGE SHOWS A WELL-DEFINED EYE SUGGESTING THAT IT HAS BECOME BETTER ORGANIZED, YET OTHER IMAGES SHOW MOST OF THE RAIN WELL TO THE  NORTHEAST OF THE CENTER, MORE TELLING OF A POORLY ORGANIZED STORM.
  • THE SHEAR HAS RELAXED OVER THE LAST 12-24 HOURS...YET PHILIPPE HAS NOT STRENGTHENED. ALTHOUGH IT MAY SOON. (Confused yet?)
Here is what should happen to Philippe:
  • NHC SAYS: IF IT REMAINS ORGANIZED, THE LOW-LEVEL STRUCTURE OF THE STORM WOULD SEEM TO BE CONDUCIVE FOR SOME INCREASE IN STRENGTH WHILE THE SHEAR REMAINS LOW. BUT....
  • WITHIN 24-36 HOURS...WEAKENING SEEMS LIKELY AS PHILIPPE SHOULD ENTER A REGION DOMINATED BY VERY STRONG UPPER-LEVEL NORTHWESTERLY WINDS ASSOCIATED WITH THE OUTFLOW OF OPHELIA.
  • ASSUMING THAT PHILIPPE CAN WITHSTAND WIND SHEAR OF THAT MAGNITUDE,THERE COULD BE AN OPPORTUNITY FOR SOME INTENSIFICATION TOWARD THE END OF THE FORECAST PERIOD.
The models suggest Philippe will move west until it runs into a wall of wind pushing off the Eastern Seaboard in about 5 days. It will also contend with Ophelia's upwelling (The movement of cold water to the surface by the storm. Ophelia is soaking up all the hot water right now as it gets stronger. As you know hot water is the fuel for tropical systems.) Once it hits this wall it should weaken and make a turn for the Western Atlantic, Bermuda may need to watch this one as well.




This is the official forecast cone from NHC.

Saturday, September 24, 2011

Low over the Bahamas

For my friends in the Central and Northwestern Bahamas, many of you have contacted me with worries regarding the area of disturbed weather over you. Right now, it is a stretched-out area of low pressure that extends from the Central Bahamas north to near the Carolinas.

The satellite imagery shows areas shaded in dark orange highlighting the heaviest areas of rain. All that is headed north and will continue to provide heavy rain for you for a few more days.



This is what NHC is saying:

  • AN ELONGATED LOW PRESSURE SYSTEM HAS DEVELOPED ABOUT 175 MILES EAST-SOUTHEAST OF CAPE CANAVERAL FLORIDA. 
  • SHOWERS AND THUNDERSTORMS HAVE BECOME A LITTLE BETTER ORGANIZED AND SOME SLOW DEVELOPMENT OF THIS DISTURBANCE IS POSSIBLE DURING THE NEXT DAY OR SO BEFORE UPPER-LEVEL WINDS BECOME UNFAVORABLE.
  • THIS SYSTEM HAS A MEDIUM CHANCE...30 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES GENERALLY NORTHWARD AT 10 TO 15 MPH. 
If it develops,  most models aim this system toward the Carolinas. We'll wait and see what develops, if anything as some strong upper winds are forecast to push off the East Coast that could destroy this tropical system.

Thursday, September 22, 2011

Ophelia is a fighter

Ophelia is up against the ropes with wind shear battering it in the mid to upper levels of the atmosphere.

In spite of this,  Ophelia has strengthened this Thursday.

Ophelia drifted over a NOAA buoy that detected stronger winds and thus as of Thursday morning, the intensity is up from 60 mph to 65 mph.



It is still a ragged looking system with much of the thunderstorm formation on the eastern semi-circle. The western side is being impacted by the shear and is almost all exposed to the elements. There are pockets of dry air ahead of it and if any works its way into the center, that could be its demise.

New satellite imagery also suggest the center is farther south than anticipated.

This strengthening should be temporary as the upper shear is expected to get stronger in the days ahead.


The latest suite of models show a more consistent track, not as fanned out as they were a mere 24 hours ago.

The Bermuda high should drift east and open a path for Ophelia to take.

This should happen in about three days.  By then , a front over the Southeast  accompanied by strong upper winds, will move offshore and protect us from Ophelia.



The official NHC forecast cone, keeps Ophelia as a Tropical Storm throughout its life cycle and moves it along the "Favored Route" this tropical season, between Bermuda and East Coast. Hopefully it won't bother anybody.




Wednesday, September 21, 2011

Ophelia



Tropical Storm Ophelia is a tad stronger this Wednesday with plenty of moisture on the Eastern Half, but the Western side remains mostly dry. This should keep it in check and prevent further intensification.

This is what NHC says about Ophelia's future:


THE UPPER-LEVEL WIND PATTERN AHEAD OF OPHELIA DOES NOT FAVOR
SIGNIFICANT STRENGTHENING.  MODERATE SOUTHWESTERLY SHEAR CURRENTLY
OVER THE CYCLONE IS EXPECTED TO BECOME MORE WESTERLY AND INCREASE
IN A FEW DAYS AS AN UPPER-LEVEL LOW FORMS NORTH OF PUERTO RICO. 
MOST OF THE INTENSITY GUIDANCE AGREES WITH THIS SCENARIO AND CALLS
FOR ONLY A LITTLE ADDITIONAL STRENGTHENING.  THE NHC FORECAST IS IN
GOOD AGREEMENT WITH THE SHIPS/LGEM GUIDANCE AND IS VERY SIMILAR TO
THE PREVIOUS ADVISORY.




NHC's  assessment is on track with the wind shear forecast map above. If you look at Friday's panel you will notice a yellow blob appearing east of the Lesser Antilles. This shear will make life miserable for Ophelia and should weaken it considerably.

But what about its track?  Only a few models take Ophelia into the Caribbean, while most curve it Northwestward into the Western Atlantic. This appears to be the favored route of systems this hurricane season.




This is the official forecast cone from NHC. The islands should keep their eyes on Ophelia as it may dump heavy rain.

Tuesday, September 20, 2011

Next Depression?

We are keeping an eye on a broad area of low pressure over 2,800 miles away from South Florida.  There is plenty of time to watch it and see what develops and where it may go.

From the satellite imagery one can see thunderstorm activity surrounding the area of low pressure.

It appears to be getting organized as it moves west toward the Lesser Antilles.

An upper low to its north has weakened and is no longer providing shear however, it still has to contend with a pocket of dry air ahead of it.

If it can overcome this obstacle it may become a depression over the next 48 hours.

If it stays on its westward track, it could be near the Lesser Antilles in about 5 days. As of this moment it's about 1500 miles east of the Windward Islands.

If it does develop, most models track it west for about 24-36 hours but then they fan out for the rest of the run. Some take it to Venezuela, others push it across the islands and into the Caribbean, while others keep it in the Atlantic. For now all we can do is watch and wait. By the way if it grows into a Tropical Storm it will be called, Phillipe. (Sorry, jumped the gun... it will be named Ophelia)


Wednesday, September 14, 2011

Maria aiming North

Maria is still headed near Bermuda, they remain under a Tropical storm warning. Bermuda may actually get winds of around 60 mph with plenty of rain.

Today, NHC was able to get a better fix on Maria's center by using some buoys that are in her path. While it shows that the system is still a tropical storm, most of the strong winds remain on the eastern half of Maria.

The image below shows the wind field of Maria in orange. If you extend this out over the next 24-48 hours, Bermuda may get a taste of this tropical storm.


Models do not hint at any further intensification. Hopefully this will only be a worry for the shipping lanes.





Tuesday, September 13, 2011

Maria's Rain

It's not Maria's future that's a menace, it's the present. It is moving painfully slow to the north and dumping rain over the same areas. One of those areas is Puerto Rico.

For our viewers with friends and family there, here is a great link to the NWS Puerto Rico site that keeps you up to date with the rain, and watches and warnings impacting the island.

NWS Puerto Rico Advisories Page

Meanwhile, once Maria gets going, it will ultimately head north threatening Bermuda before moving into the Hurricane Graveyard... the cold waters of the Northern Atlantic.  Models do not hint at any further intensification. Hopefully this will only be a worry for the shipping lanes.


Monday, September 12, 2011

Maria's ups and downs

This tropical system looks good one moment and poor the next.  As of this moment only Bermuda needs to watch it carefully.

Maria looks sheared this Monday, and its center of circulation is hard to find. You can barely see a swirl due North of Puerto Rico. Most of the strong winds, clouds, and rain are on the eastern semicircle since the western is completely exposed. This is due to shear from a persistent upper low just ahead of it. Even though some models had been forecasting this low to weaken, it hasn't , and it has kept Maria at bay.


Next for Maria is to get pushed away from the Bahamas and the Eastern Seaboard by strong upper level winds. This will act as a wall pushing Maria North.

Unfortunately this will keep the storm on a track toward Bermuda. By then, it could be as strong as a category one system.  This intensification remains doubtful since the shear may not relax throughout its duration. Maria will also be traveling almost the identical route as "Katia" and that system has already soaked up much of the heat energy from the ocean on that route. This means there is little fuel for Maria to use.

We hope this remains a worry only for shipping lanes and that Maria mercifully meets its end over the cold waters of the Northern Atlantic without incident.


Sunday, September 11, 2011

Maria

Oh Maria, you trouble maker you. In spite of strong upper winds battering you and keeping you looking ragged, you have persevered. This morning you are looking better.


Maria finally has the more familiar shape of a tropical storm and there is even a good outflow pattern developing in the upper levels.

Morning recon suggests that even though the strongest winds are in the northeastern quadrant, the center is better defined. This is confirmed by surface observations across the Leeward Islands.




Water vapor images still show the upper level low to Maria's Northwest.  This is causing the shear that has kept it in check, but today Maria is fighting back.  Even though there is plenty of dry air ahead of it, and models insist on the upper low hanging around a few more days...Maria is getting stronger.




So where is Maria headed? NHC says it best:

  • MARIA IS MOVING TOWARD THE NORTHWEST . THE CYCLONE IS EXPECTED TO BE TRAPPED BETWEEN THE ATLANTIC SUBTROPICAL HIGH AND A TROUGH ALONG THE EASTERN UNITED STATES.  

  • THIS IS THE SAME STEERING PATTERN THAT IN GENERAL HAS PREVAILED THIS SEASON... (this should take) MARIA WELL NORTH OF THE BAHAMAS...AND THEN RECURVING IT BETWEEN THE UNITED STATES EAST COAST AND BERMUDA.


The official forecast cone from NHC intensifies Maria into a hurricane by Wednesday, by then only Bermuda should be at risk. We hope this one too will follow in Katia's footsteps and not bother any land mass.

 

Saturday, September 10, 2011

Down to two

Of the three systems we are watching in the Tropics, Katia, is no longer being followed by NHC. Even though it's no longer a Tropical Cyclone, it will still pack gusty winds and rain as it aims for the British Isles. That now leaves us with Maria, and Nate. We begin with Maria.

Maria is looking extremely ill with an elongated shape to it.

It has a weak center of circulation exposed to the elements on the western semicircle and what gusty winds remain are far removed from it.

The only reason NHC is keeping it as a Tropical Storm is because, at least for now, there is still a weak circulation center.


This is what early recon had to say about Maria:


THE INITIAL INTENSITY IS GENEROUSLY
KEPT AT 35 KT...WITH THE ASSUMPTION THAT TROPICAL-STORM-FORCE WINDS
ARE OCCURRING IN THE CONVECTION WELL TO THE NORTHEAST OF THE
CENTER.  BECAUSE THESE WINDS ARE SO FAR REMOVED FROM THE
CENTER...AND NOT EXPECTED TO IMPACT THE LESSER ANTILLES...ALL
TROPICAL STORM WARNINGS HAVE BEEN DISCONTINUED.


That weak center of Maria is over Antigua. You can see Antigua highlighted in red on the map below on  center-right. Most of the rain and wind is to the Northeast of the Leeward Islands. About the only effects they may feel are breezy conditions and choppy seas, with an occasional t-storm.


So why is Maria so disorganized? For that answer we have to use the water vapor imagery. While a regular satellite image helps us see what is near the surface, this image gives us a view of what's happening in the upper levels of the atmosphere.

Here you can see the cloud cover over the Lesser Antilles belonging to Maria. You will also notice a dark inverted comma shape pattern just to its northwest. This is an upper low and it's responsible for shearing Maria apart.  This feature should remain for another 48 hours, if Maria can survive until then, it could restrengthen.



So if it survives, where is it headed?

Most models now keep Maria as Tropical Storm over the weekend as it moves North of the Leewards and Puerto Rico. It should then be pushed away from Florida and the Southeast by strong upper winds coming off the Continental US. After that, it may be a worry for Bermuda.




Now we check up on Nate:

This is a beautiful looking storm with plenty of banding and typical circular shape. It lacks however, a well organized inner core.

Models hint at slow intensification as it moves west toward Mexico. Even though the forecast cone shows Nate as a storm throughout its duration, it may have just enough punch to reach hurricane status before landfall.

The biggest threat will be rain as it could cause flash floods, land and mudslides from the coast to far inland locations.



Friday, September 9, 2011

Maria on the ropes

Early recon suggests Maria has more thunderstorm activity on the Northern side of the storm but still remains a disheveled looking system.

Hurricane hunters also found light winds on the West and Southwest sectors of Maria. They clocked 45 mph winds on the Eastern side, but could not detect a well defined center of circulation. This is not a well organized system.

So why are they still keeping it as a Tropical Storm? 

NHC says recon found flight level winds indicating there is still a broad circulation and so they will keep it as a storm. 

Recon has yet to analyze the northern end of Maria where they believe the strongest winds will be found.




There are the things still working against Maria:
  • An upper low ahead of it is causing shear and keeping Maria weak. This low should remain for another 2-3 days.
  • Dry air is moving in from the South

What Maria has in its favor:
  • Determination. If it can survive all these roadblocks, shear will relax in the long haul and it could get stronger.
  • Models now have it becoming a hurricane on Tuesday


The models keep pushing Maria through the islands and ultimately making a turn north over the Southeastern Bahamas. At this stage, wind will not be a problem but the rain will be. From the Leewards though Puerto Rico, flooding from heavy rain could be a threat.




The official forecast cone tracks Maria over most of the Lesser Antilles and then push it to the Northwestern Bahamas. South Florida is NOT in the cone, but we should keep our eyes on it, just in case it decides to surprise us.








Aside from Tropical Storm Watches and Warnings, there is also the concern for flooding for the islands. Puerto Rico has issued the following statement.
  • THERE IS A SERIOUS CONCERN FOR A SIGNIFICANT HEAVY RAINFALL AND FLASH FLOODING EVENT ACROSS THE REGION DUE TO RECENT HEAVY RAINS FROM IRENE.  THERE IS ALSO A CONCERN FOR THE POSSIBILITY OF DAMAGING WINDS TO THE NORTH AND EAST OF WHERE THE CENTER TRACKS.
  • REGARDING THE COASTAL WATERS UNDER A WATCH...SMALL CRAFT SHOULD RETURN TO PORT OR SEEK SAFE HARBOR.

We'll keep watching it.

Thursday, September 8, 2011

Maria

A recon flight has been probing Maria since 9:30 am. So far initial readings are not that impressive: Pressure is around 1008 to 1009 mb up from 1005 yesterday. Top winds are hovering near 35 mph.

As more data comes in we'll get a better handle on its health and a good fix on the center. This may lead to a repositioning and maybe a different cone forecast.


Communication problems from a Thursday night recon mission failed to fully get a clear view of the inner workings of Maria.

Some more thunderstorms are developing in the Northern semi-circle of Maria this morning. It still remains a ragged looking storm with the center of circulation exposed to the elements on the Southern sector with all the rain on the Northern side.



There are many things working against Maria:
  • An upper low ahead of it is causing shear and keeping Maria weak
  • Dry air is moving in from the South

What Maria has in its favor:

  • The shear is expected to relax late Today
  • Models are being very aggressive now, keeping Maria as a storm and even intensifying it as she nears the Northwestern Bahamas.

The forecast maps below show how weak or strong the shear will be through Monday. The reds and yellows represent weak shear while the green and blues suggest stronger shear. Right now, Maria is dealing with strong upper winds to the Northeast, but by Saturday it relaxes over Hispaniola. Could it be enough for Maria to get its act together?




The models are now more in consensus taking the system through the Leeward Islands and then Puerto Rico.  At this stage, wind will not be a problem but the rain will. They could see some flooding as Maria moves over them over the weekend.




The official forecast cone tracks Maria over most of the Lesser Antilles and then push it to the Northwestern Bahamas. South Florida is NOT in the cone, but we should keep our eyes on it, just in case it decides to surprise us.


Aside from Tropical Storm Watches and Warnings, there is also the concern for flooding for the islands. Puerto Rico has issued the following statement.
  • THERE IS A SERIOUS CONCERN FOR A SIGNIFICANT HEAVY RAINFALL AND FLASH FLOODING EVENT ACROSS THE REGION DUE TO RECENT HEAVY RAINS FROM IRENE.  THERE IS ALSO A CONCERN FOR THE POSSIBILITY OF DAMAGING WINDS TO THE NORTH AND EAST OF WHERE THE CENTER TRACKS.
  • REGARDING THE COASTAL WATERS UNDER A WATCH...SMALL CRAFT SHOULD RETURN TO PORT OR SEEK SAFE HARBOR.

We'll keep watching it.

Maria a worry? Only if it survives.

The Forecast Cone for Tropical Storm Maria shifted west on Thurday and in the long run it could come close to South Florida....that's if it survives.


Here is the latest:

  • Maria is looking awful on satellite with most of the storms far removed to the northeast of the center of circulation.
  • Right now conditions are a bit hostile in the upper levels of the atmosphere but they will become more favorable in the days ahead.
  • Even if it falls apart into a wave, it may still come back to life.

The models are in fair agreement that whatever remains of Maria over the next few days, should impact the Leeward Islands, Puerto Rico and Hispaniola. Advisories have been issued for parts of the Leeward Islands.

The biggest threat from this system will be in the form of rain, it could produce flash floods, land and mudslides.


Where is it headed?

  • Maria is on the south side of the Bermuda high
  • It should move west for the next three days
  • By the fourth day, IF IT SURVIVES. the Bermuda high moves east and allows whatever is left of Maria to turn north. The question is... Will it miss land? We'll have to wait first to see if it survives and then if  it will be strong enough to be a worry.


Wednesday, September 7, 2011

Busy NHC

Plenty of activity in the Tropics. This Thursday, NHC is following Hurricane Katia, Tropical Storm Maria, and Tropical Storm Nate. I will cover Katia, and Nate here, I have given Maria a separate blog update all its own since it could be a headache down the road.


You can see the three systems on the graphic to the left.

We have "Nate in the Gulf", "Katia" in the middle of the Atlantic, and "Maria" in the far Eastern Atlantic.

Katia is being impacted by shear and thus is looking a little disheveled. The western side is exposed to the elements with dry air filtering in.



The eyewall replacement cycle I mentioned on Tuesday halted for some reason and has kept her intensity in check.

It seems Katia may not get a chance to get its act together again. It has about 48 hours worth of warm water fuel, after that, it's the hurricane graveyard (Northern Atlantic) for her.

Katia will not go down quietly however, while she may lose her tropical characteristics in the days ahead, she will remain a powerful force throughout the higher latitudes posing a huge threat to marine interests.


Katia should thread the needle as far as her track is concerned.

Most models move her in between Bermuda and the East Coast as she heads to the Northern Atlantic. About the only effects to be felt will be in the form of choppy seas and dangerous rip-currents.








We now turn our attention to the Southwestern Gulf of Mexico. We now have Tropical Storm Nate. It remains stationary in the Southeastern Gulf soaking up heat energy. It may become a hurricane over the next 24 hours.

It will eventually move north, then west and possibly impact Central Mexico in about 5 days.


Tuesday, September 6, 2011

Katia - in a pit stop

Katia appears to be losing a bit of its fury after revving up to Major Status over the holiday weekend. Even though it remains a well structured hurricane with good banding and outflow, its eye is no longer visible.

It is undergoing an eyewall replacement process, almost like a race car going through a pit stop and replacing its tires before going back out full throttle, this is similar to what is happening to Katia right now.  It should remain a major storm for at least another 24-48 hours before running out of fuel in the form of warm water.

Traffic will also get a tad more congested as upper winds will begin to move in and hopefully keep Katia away from the East Coast. As of this writing it should miss Bermuda.   OK, enough with the racing analogies... but you get the idea.


Its present movement has been a tad jerky. NHC described it as "EXHIBITING A TROCHOIDAL MOTION". This is terminology you don't hear about every day, but it's almost like a bicycle wheel where the eye of the hurricane rotates in a circle while the entire storm moves in a straight motion.


Even though it's moving Trochoidally, most models agree that Katia should track in between Bermuda and the US, being pushed back out to sea by a front and strong upper winds coming off the Eastern Seaboard. Once it loses its warm fuel supply it should weaken rapidly and ultimately be absorbed by the same front protecting the coast.




Here is the official forecast cone from NHC.

Sunday, September 4, 2011

Katia is stronger

There is no doubt that Hurricane Katia is a good looking strong system. Satellite imagery clearly shows a well organized storm, with an eye at its center, good feeder banding and nice outflow.

Intensity forecasting is one of the most difficult things to do but as of now, conditions appear favorable for Katia to continue growing in strength. By the end of the week it should be out of the warm water stream that is feeding her now, and she should begin to lose her intensity.

It will continue to head on a northwesterly track over the next few days as high pressure builds back toward the west. This should keep Katia aiming for the East Coast.  Models are in fair agreement that by mid week, the high will move back into the Atlantic and permit Katia to turn north. The system may get uncomfortably close to the US before turning away.

This is the official forecast cone. By day four, Katia should make a turn North, if it doesn't,  Katia could impact the Northeast. They are still cleaning up from Irene's wrath.