The waiting game

NHC continues to watch an area of low pressure in the Mid Atlantic Ocean over 2,500 miles away from South Florida. They are giving it a 50% chance for development over the next 5 days, down from a high of 80% a couple of days ago.

While it's physical appearance is good, the inner workings are still not firing on all cylinders. Dry air to the north is robbing much needed moisture required for growth, while at the same time, sea surface temps are not hot enough to overcome that lack of moisture.

The color enhanced satellite imagery shows good spin, but most of the dark colors, which indicate t-storm activity, can only be found in the southern half.

More rain is needed around the center for it to become a healthy system.

Surface winds however, are near depression strength of 35 mph, so there is a chance it could still be called a depression later today.

Because it is aiming for the Lesser Antilles, roughly 1100 miles away, everyone there should keep an eye out just in case this low gets its act together.

The models are almost unanimous that it will track towards the islands and then come close to Puerto Rico over the weekend.

After that the tracks start to fan out, with some models keeping it over the NW Bahamas and others turning it away from the US.

At this stage of the game the models do not have a good handle on possible tracks. Since there is really no well defined center, or a good starting point, the end results provided by the models tend to be sketchy.

All we can do is wait and see what and if something develops.

"Bertha" in the makings?

As of 8 am Tuesday, the area of clouds and rain East of the Lesser Antilles, is looking better and better. It may become a depression or even Tropical Storm "Bertha" over the next 48 hours.

On the color enhanced satellite imagery one can see a definitive spin. NHC now says an area of low pressure is present within this cluster of clouds roughly 1600 miles East of the Windward Islands.

The low is moving west at around 10 to 15 mph.

The darker colors represent where the strongest
t-storms are present.

This will fluctuate throughout the day as the low deals with some drier air to its North.

NHC is giving this feature anywhere between a 70 to an 80% chance for development over the next few days.


The detailed Visible Satellite picture has a clear view of cloud banding starting to take shape.

It can be found at Lat: 9.9 N and Lon: 37.3 W with estimated winds between 29 and 34 mph, just below the 35 mph threshold to be classified as a depression.

The government of Venezuela has issued a precautionary alert for the Lesser Antilles.

Regardless of strengthening, this low has the potential for squally weather across the islands.

So where is it headed?

Right now most early model runs aim whatever develops towards the Leeward Islands, being pushed along by the Bermuda High.

An out-of-season cold front sitting across the Southeastern US could play a big role in protecting Florida and the Bahamas from this feature. If the front moves South just enough and does not weaken, it could act as a shield pushing the system East into the Atlantic waters.

Still too early to tell. Very few models handle disturbances accurately, they need to have a good fix and an organized feature to be able to issue accurate tracks. As of this update, this feature is just an area of low pressure.

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Invest 93

A tropical wave almost 3,000 miles away from us in the Eastern Atlantic is being eyed by NHC. They are giving it a 30% chance for development over the next 48hours, but a 70% throughout the next 5 days.

As of the Monday afternoon NHC update, they suggest t-storm activity has increased with this tropical wave, but it still remains disorganized.  The thinking is that over the next 120 hours environmental conditions will become a bit more favorable for it to get its act together. Some models suggest it may become Tropical Storm "Bertha" during that time frame.

This wave, deemed Invest 93, (NHC would like to INVESTigate it further), is traveling west at around 10-15 mph.

This enhanced colorized satellite view shows you just how much t-storm activity there is with this wave. The darker the colors, the more activity, and a possible early sign it's trying to develop.

The long range models: If everything stays as is, it should impact the Leeward Islands in about 5 days, after that still too early.  This system could dump heavy rain across the islands with gusty winds.

Something to watch

7Weather has been following an area of disturbed weather over the Central Atlantic since last Saturday.  Even though it's surrounded by dry air and hostile conditions it promises to develop in the next few days. It may become a depression or possibly TS "Bertha".

NHC gives it a 70% chance for development over 5 days. By then it may be close to the Lesser Antilles. Long range models are not in agreement as to where it may go afterwards. Some keep it in the Caribbean while others displace it across the Bahamas and east of the mid Atlantic states.

I'll wait for the afternoon discussion from NHC to give our friends in the Caribbean a more detailed assessment.

For the moment here's the last update from NHC.


http://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=5

TD #2

Tropical Depression #2 was born on Monday out of an area of clouds and rain in the Central Atlantic over 2000 miles away from us.

As of Tuesday morning it remains rather weak with the possibilities of getting stronger fading away rather quickly.

As of the 11 am advisory, it has 35 mph winds, moving west at 17, and is roughly 900 miles east of the Lesser Antilles.

The color enhanced satellite imagery details where the strongest thunderstorms can be found. From time to time some bursts of red will pop up indicating the strongest activity.

So far most of that rain has been in a line to the west and east of the center.

This depression is fighting a losing game as it is surrounded by very dry air. This will continue to rob its potential for growth.  Some models have the depression falling apart in 48 hours.

If it does manage to survive the next 24 hours, NHC places it near the Lesser Antilles by Thursday morning as a weak area of low pressure.

Meanwhile our weather is being dominated by a wave in the SW Caribbean, a low to our north, and high pressure to the east.  All these features in one way or another are helping to drag and trap moisture here. Expect soggy conditions through Wednesday.

This water vapor imagery highlights all the dry air in brown (also impacting TD#2) sitting to our east, while we remain cloudy and damp.

Wednesday promises to be wet also, with slowly improving conditions by Thursday.

UPDATE: Invest 92

As we get underway with this new work week there is a small feature to watch in the Eastern Atlantic. This area of clouds and rain can be found over 1200 miles WSW of the Cape Verde Islands. It is moving west at a steady clip of 15-20 mph.

NHC has deemed this feature INVEST 92, as it is an area they would like INVESTigate further.
Over the next few days this feature will continue to move west with the possibility of some gradual organization. After that, most models indicate it will enter an area more hostile for growth.

Update: NHC is upping the chances for development to 70% through 120 hours. 

Shower activity associated with a small area of low pressure located
about 1250 miles east of the Lesser Antilles has continued to
increase and show signs of organization during the past few hours.
Satellite data indicate that the circulation has become better
defined and the system is producing a small area of winds near
tropical storm force. Only a small increase in organization of the
shower activity would result in the formation of a tropical
depression as the system moves westward to west-northwestward at 15
to 20 mph during the next day or two.  After that time, however,
environmental conditions are expected to become less conducive for
development or strengthening. Interests in the Lesser Antilles
should monitor the progress of this system.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...70 percent.

 It may become a depression or a storm in that time frame.

Many of you have asked about the spaghetti models placing us in its path down the road, are we to worry? First, most models do not handle these small features well. They need something organized in order to get a good fix so they can issue a forecast. Second, some models are good for short term forecast, others long range, some are specialized to look at a certain level of the atmosphere, while others look at the system's entire environment. All need a good fix and an organized feature..

If  it does become a depression or a storm over the next few days then the long range models will have a better handle on it.

Top 5 Sky Views so far this Year

We begin with number 5:

Early in January we had some mid level clouds move in ahead of a weak front. The setting rays bounced off that light giving us beautiful orange and red hues. It was truly beautiful.

Number 4:
In April, cumulus clouds blocked some of the sunset providing these "Crepuscular Rays". The name crepuscular means "relating to twilight" and these rays are observed at sunrise and sunset.

Number 3:
This sunset happened in June under clear skies. As the sun goes down it leaves behind mostly red hues. This one was spectacular.

Number 2:
This one is one of my favorites. This is looking SW from our Channel 7 studios on Biscayne Bay. Those towering cumulus clouds are from thunderstorm over the Everglades very near Mainland Monroe. Its amazing how huge they look and how far away they are.

Number 1:
This one was taken on Thursday July 17th after a day heavy rain. The cloud cover cracked open just enough to allow the sun's rays to filer through. It was a beautiful end to a gray and damp day.

Polar Vortex Again?

It appears the push of Cold Arctic Air we have come to know as the "Polar Vortex", will make an unscheduled summer appearance by early next week. This time however, its just the jet stream's fault.

Why?:
The jet stream, which is like a strong river of wind in the upper levels of the atmosphere, will take a dip South and drag cold air with it. This event will not be as brutally cold as its winter appearance but none the less, temps will be running a good 20° - 30° below average.   Lows are projected to hover in the 40's with highs in the 60's.

Most folks in the Northern Plains and Upper Midwest are used to this kind of weather, but after such a brutal winter, this is almost a cruel joke by Mother Nature.

The out of season cool temps will not stop there, they will make a turn towards the East and arrive at the Coast by the middle of next week. The Summer Chill may last through next Friday.

Any cool air here?
None of this delightfully cool air will make it here. As a matter of fact, we are forecast to remain in our soggy pattern for quite a while.

"Arthur" - Season's 1st Hurricane

"Arthur" intensified overnight into a Category 1 system with 75 mph winds, and as of mid-morning the winds had picked up to 80 mph. The satellite imagery shows a more concentric, more symmetrical hurricane this morning as it aims for the Carolina's at around 9 mph.

The feeder bands continue to supply it a steady stream of warm, moist tropical air, and this should keep it healthy over the next 24 hours.

For the moment it is still encountering a bit of "dry air hangover" from yesterday so it may not be able to take full advantage of the very warm waters it is traveling over.

On Friday upper level conditions become a bit more hostile for "Arthur" and it will begin to lose some strength.

By the weekend it should be over the Canadian Maritimes nearing its end.

The rain is already coming ashore.

Forecast totals suggest anywhere between 1-4" along the path with some isolated areas receiving as much as 6 inches.

That will lead to flooding and cause some rivers to swell.

Massachusetts and parts of the Northeast could see some rain by the weekend.

In the long run, it appears that outside of the Barrier Islands, most of the heavy high rain totals should stay offshore throughout "Arthur's" duration.

FORECAST RAIN TOTALS

Most of the Eastern Seaboard will feel some of "Arthur's" winds as noted by the yellows and greens on the wind forecast graphic, but the brunt of the storm will be felt by the outer banks of North Carolina.

For South Florida, there may be enough moisture left behind by "Arthur", that coupled with our daily sea breeze interaction, could fire up a storm or two.

We should see typical rain chances this weekend.

Mother Nature should keep its fireworks well to our north.

By the middle of next week we may see a tropical wave over us pumping more moisture.

Until then….

"Arthur" a little stronger

It's a little ironic as "Arthur" tightens up its spin and gets a little stronger, its drawing more clouds to its center and away from us. We should see more sun today, but it doesn't mean we are out of the woods as far as rainfall.

We could still see some feeder bands move over us bringing quick tropical downpours. "Arthur" is a couple of hundred miles to our northeast, and any hiccup there impacts us here.

Even though early Wednesday morning "Arthur" looked a little disheveled, its pressure dropped overnight, and that is a key indicator that it means business.

Its top winds have climbed from 40 mph on Tuesday morning to 60 mph today.



But where are those 60 mph winds?
Fortunately most of the strong gusty winds are offshore.
 The wind graph shows the red dot as the center of "Arthur".

Tropical storm force winds extend out roughly 80 miles from the center and are illustrated with the orange circle.

As of this moment, "Arthur" is a nuisance mainly for marine interest but it may be a lot worse in the days ahead.

NHC will have recon missions scheduled to keep close tabs on "Arthur's"Progress.



Here's what NHC is saying:

Arthur is still suffering the effects of dry air aloft being
entrained into the western half of the circulation, which
features only limited cold cloud tops. The primary convective band
is situated east and southeast of the center, and some semblance of
an eye has been visible in satellite and radar imagery and was
reported by the aircraft. 

This means there is a road block of dry air to its north, that it must defeat before it can get stronger. Because of this dry air, the only pocket of heavy rain present is on the eastern side of the storm. 

Until it can overcome this dry air issue, it will not reach hurricane status, but in the days ahead models suggest the road block will disappear and conditions will improve for "Arthur" to become the season's first hurricane.

The jet stream should pick up "Arthur" over the next day or so and drag it northeast very close to the Eastern Seaboard. 

The Barrier Islands of North Carolina could get Mother Nature's fireworks this 4th of July, and even Massachusetts could be grazed down the road as well.  

What can we expect?:

Another rain band or two can move over South Florida and the Bahamas this Wednesday. In the long term as Arthur moves away, we will return to our typical summer time pattern of morning sun, heat, and humidity with afternoon storms.

We'll keep you posted

1st Tropical Storm of the Season

And so we have, "Arthur".

NHC says that more thunderstorm activity has been spotted this morning around the center of circulation along with steady winds of 40 mph (mostly out of Grand Bahama Island), because of this  TD#1 has been upgraded to Tropical Storm "Arthur".

The storm is now drifting northwest but it should eventually start moving north as strong upper winds start pulling it that way.

There is still a chance it could become a hurricane as it nears the Mid-Atlantic states by the end of the week.

What does this mean for us:
The following message is from the local NWS office:

THE MAIN CONCERN CONTINUES TO BE THE POSSIBILITY OF URBAN FLOODING ASSOCIATED WITH HEAVY RAINFALL BANDS. THE GREATEST THREAT WILL BE ACROSS THE EAST COAST METRO AREAS.

As of this update, most of the heavy rain remains over Grand Bahama Island, but some of that could arrive here later today. We'll keep you posted.

Tropical Depression #1

As of Tuesday morning the depression remains poorly organized and nearly stationary almost 100 miles East of Cape Canaveral. NHC declared the low to be a Depression, the first of the 2014 season, late Monday night.

Satellite imagery shows the northern half of the low, to be void of cloud cover and rain while most of the downpours are offshore and over the Northwestern Bahamas. Grand Bahama Island, Andros, and Nassau, have been drenched over the last 48 hours, and it appears more rain is still possible.

Notice the blues and oranges in the color enhanced imagery, these are the areas of heavy rain sitting South of the Low.

This is the pattern we have seen since Monday and as of today, there is no change in structure or organization. This depression remains weak, mostly a rainmaker so far.


What's next? Here is what NHC is thinking:

Numerical guidance shows favorable conditions for intensification with weak shear and developing upper-level outflow over the cyclone during the next 72 hours or so.  

The official intensity forecast now shows the system becoming a hurricane, which is similar to the
latest intensity model consensus.

Models suggest that the upper air environment will become favorable for this depression to become Tropical Storm "Arthur" and may even reach Hurricane status in the long run.  Strong upper winds should drag it away from us and push it towards the Middle Atlantic States. It may be close to the North Carolina, Virginia border by the fourth of July. This could be a big holiday mess for them.

For the time being NHC has the following advisory in place:
A TROPICAL STORM WATCH  FOR EAST COAST OF FLORIDA FROM FORT PIERCE TO FLAGLER BEACH.

What can we expect: 
It will remain mostly cloudy with a chance for downpours for South Florida and NW Bahamas through Wednesday. After that, as the depression begins to move North, our conditions will improve and we should return to our typical Summer Time pattern of morning sun and afternoon storms, by Friday.