Category: Tropical

Matthew Close to Cat Five Intensity

| September 30, 2016 @ 9:49 pm

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We haven’t seen a category five hurricane in the Atlantic Basin since 2007, a year that saw two of them (Felix and Dean).

Matthew may be about to change that.

Hurricane Matthew has been intensifying rapidly for the past 24 hours in the Central Caribbean. Between 4 p.m. CDT yesterday and 4 p.m. today, Matthew’s central pressure dropped from 993 millibars to 949 millibars, or 44 millibars. That officially satisfies the 42 millibar drop that defines rapid deepening.

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Its central pressure has dropped to 944 millibars shortly before 8:30 p.m. CDT tonight, a 51 millibar drop in 28.5 hours. The plane estimated surface winds of 158.8 mph, which is very close to the category five threshold of 160 mph. The eye is closed with a diameter of 12 nautical miles.

The storm continues moving west southwest. It is expected to turn northwest tomorrow night and will impact Jamaica Sunday night and Monday. It is forecast to have top winds of 120 mph at that time, making it a category three hurricane. But it could be stronger.

It will cross eastern Cuba and move through the Bahamas Tuesday and Wednesday. It is too early to tell if Matthew will strike the U.S. The general indication is that the hurricane will turn north and northeast after coming menacingly close to the coast between Florida, the Carolinas, Mid-Atlantic and Northeast.

There were six category five hurricanes between 2003 and 2005. Wilma was the last in that group, and the last major hurricane to hit the United States.

Will the Record Be Unbroken? By and By, We Will Tell.

| September 25, 2016 @ 2:58 pm

By and by, we will find out whether the U.S. streak of no landfalling major hurricanes will remain intact. It was been 10 years 11 months and 2 days since a major hurricane hit the United States (Hurricane Wilma on October 24, 2005). That record obliterated the old record of eight years set in the 1860s. That’s 131 months 2 days. That’s 570 weeks. That’s an amazing 3,990 days.

DROUGHT BUSTER? Often, we look to dying tropical systems to spell the end of a southeastern drought. Let’s just hope it does come on the business end of a major hurricane.

MATTHEW THIS WEEK? The tropical wave that will likely become Matthew most likely is about 1350 miles east of the southern Windward Islands this afternoon. Low pressure should develop by Tuesday as the system approaches the southern Antilles. There is a chance that it will be a tropical storm as it enters the southeastern Caribbean. It will be very far to the south, hugging the coast of Venezuela before entering the Central Caribbean late next week. Then it will be entering very favorable conditions and we could be dealing with a major hurricane as it approaches Jamaica or Hispaniola next weekend.

IMPOSSIBLE TO SAY: After that it could affect Cuba, the Florida Keys, western Florida, the Florida Panhandle, the Central Gulf Coast, the Bahama, or Mexico. It could miss the United States entirely. Nothing like a specific forecast, huh? But it is just impossible to say at this point. Suffice to say, everyone with interests along the Gulf Coast will want to keep one eye on the progress of the system over the coming two weeks.

MODEL MADNESS: It’s still model madness and a voodoo sandwich at this point, with every run of the model controls pointing to a very different solution. The ensemble output of the two global models is still all over the board as one would expect, but some consistency did emerge last night and this morning.

Here is the output of the GFS Ensembles showing possible tracks. You can see that it is focusing on the area between the Florida Keys, South Florida and the Bahamas up into the Carolinas.

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Here is one set of the European model’s individual ensemble members for Thursday morning the 6th based on last evening’s run. The ensemble runs come by varying the input slightly each time to produce a different possible result. When there is good agreement among the members, you have have more confidence in that model run. You can see all of the different ideas on the table in the various outputs:

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The just shows some of the various options on the table for no.

There is actually one more set of ensemble outputs to go with these. But I counted up all 50 ensemble members this morning, and the winner (or loser) was the Florida Keys or the Bahamas with 16 of the 50 runs targeting them. There was about a 50/50 split between the Keys and the Bahamas. Interesting to note that Alabama/Mississippi region showed as a landfall point for 4 of the members. The biggest majority was no storm or no landfall. That seems unrealistic at this time.

Here is the control run of the European from the morning. It shows a hard right turn into Hispaniola on Wednesday on Tuesday October 4th.

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Here is the control from the GFS for the same time:

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It shows a similar solution to the European. If that materializes, the U.S. landfalling major hurricane record may remain remain unbroken. And we shall remain dry.

REST OF THE TROPICS: Karl is now a post tropical storm over the North Atlantic. Advisories have been discontinued. Karl passed south of Bermuda Friday night and Saturday morning, bringing tropical storm force gusts to the island nation along with heavy rains. About 800 homes were without power yesterday and there were big swells and waves. No injuries were reported. Bermuda is used to passing hurricanes.

Tropical Depression Thirteen Forms

| September 19, 2016 @ 4:21 pm

The National Hurricane Center (NHC) has begun issuing advisories on Tropical Depression Thirteen. Satellite imagery, scatterometer data, and ship observations this afternoon indicated that the large low pressure system located southwest of the Cabo Verde Islands has maintained a well-defined circulation and has developed enough organization to be considered a tropical depression.

The initial intensity of the depression was set at 30 knots based on scatterometer wind data of near 30 knots. The central pressure is based on reports from a ship observation during its traversal through the center of the cyclone over the past 12 hours. This depression is a large tropical cyclone with a
wind field that is more than 400 nautical miles in diameter.

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The initial motion estimate was an uncertain 280/10 kt, based primarily on satellite data. The depression was located along the southern edge of a large deep-layer ridge that is forecast to steer the cyclone westward for the next 24 hours or so. After that, the cyclone should follow a west-northwestward motion through 120 hours. The official NHC forecast track lies close to the consensus model TVCN through 96 hours, and then leans toward a blend of the ECMWF, UKMET, and CMC models since the GFS dissipates the cyclone by 120 hours, a scenario that seems premature given the current large size of the cyclone.

Vertical wind shear was forecast to remain low at less than 10 knots over the cyclone for the next 48 hours. This favors steady intensification. However, mid-level moisture is only expected to be marginal during this time with humidity values around 60 percent or less. The drier air along with the large size of the cyclone are expected to temper the development process, and this was reflected by the slower-than-average intensification rate.

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All in all, while the storm may become the next named tropical system Lisa, it appears likely to remain well out in the open Atlantic.

-Brian-

Tropical Low Along the East Coast of Florida

| September 13, 2016 @ 3:02 pm

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A tropical low is just east of Daytona Beach this afternoon. It has a chance to become a tropical depression or tropical storm this afternoon.

The low is moving to the north northwest toward Jacksonville.

It has produced wind gusts to tropical storm force (39 mph or greater) along the coast.

Gale warnings are in effect for the coastal waters. A tropical storm warning may be required for the immediate coast and coastal water later this afternoon.

Hermine Nearing The Coast

| September 1, 2016 @ 8:40 pm

The eye of Hurricane Hermine is only about 40 miles south/southeast of Apalachicola at 8:30 this evening…

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Note the tornado warnings in the spiral band east of the storm center.

Landfall will come shortly on the Florida coast south of Tallahassee, and east of Apalachicola. Sustained winds are now 80 mph, Hermine is still a category one hurricane. It will be first hurricane to move into Florida since October 2005 (Wilma).

IMPACT: The main risk of storm surge inundation, flash flooding, and tornadoes will be east of the landfall point. Rain totals of 5-10″ are likely with a significant storm surge around Apalachee Bay, greater than 9 feet above ground in places.

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Hermine will move into South Georgia after midnight, and into eastern South Carolina tomorrow afternoon.

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GULF COAST FORECAST: Rain will end early tomorrow on the Gulf Coast, with clearing during the day. The sun should be out nicely from Gulf Shores to Panama City Beach by afternoon with only a few lingering scattered showers or storms.

Then, we expect 7 to 9 hours of sunshine each day Saturday through Monday with the routine risk of scattered storms; highs in the upper 80s on the immediate coast, with low 90s inland. All in all a nice Labor Day weekend.

And, the sunset this evening was amazing at Panama City Beach and Destin; they are on the “good” side of the hurricane with an offshore wind flow.

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We should also note that the rip current danger will slowly subside tomorrow and Saturday on the Gulf Coast as Hermine moves northeast away from the area.

Watches Issued For Part Of Florida’s Coast

| August 30, 2016 @ 4:28 pm

The NHC track for Tropical Depression Nine has been shifted a little to the left… as it approaches they have issued a hurricane watch from the Anclote River to Indian Pass. A Tropical Storm Watch has been issued for the Florida Gulf Coast west of Indian Pass to the Walton/Bay County line.

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Scroll down to the post below this one for a detailed look at what to expect on the Central Gulf Coast, and the Alabama weather situation…

First Eight, Now Nine

| August 28, 2016 @ 4:53 pm

Earlier today we announced the birth of Tropical Depression Eight. Now, just six and a half hours later, we have Tropical Depression Nine.

Data from a NOAA Hurricane Hunter aircraft this afternoon indicated that the area of low pressure located in the Florida Straits had a well-defined center. Satellite imagery also showed a significant increase in the convective organization today, so NHC has now classified this system a tropical cyclone. The initial intensity is set to 30 knots based on the highest reliable wind data from the aircraft. The aircraft also reported a central pressure of 1009 mb. Interesting that this is actually a lower pressure than the 06Z GFS run projected this morning.

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The depression is still moving through a marginal environment for intensification and will be doing so for the next day or so. Only slow strengthening can be expected during the short term. After a day or so, the environment should improve a little as the shear is forecast to decrease somewhat and become southwesterly, which should permit a little more strengthening. But there are some mixed signals from the models. The ECMWF is now showing the cyclone dissipating in the Gulf while the GFS delays development until 4-5 days. The 00Z run of the ECMWF was much stronger this morning, but no most of the tropical cyclone guidance is more aggressive. Given this uncertainty, the NHC intensity forecast is conservative and shows the system peaking at 45 knots, below all the explicit intensity guidance. As you can probably imagine, confidence in the intensity forecast is even lower than
usual for this system, something we’ve seen throughout its history.

The initial motion estimate is 270 degrees at 9 knots, but the confidence here is low, too, given the recent formation of the center with little real history to go by. The cyclone will be steered in the short range by the mid-level ridge centered over the Southeast United States. As we noted in the Weather Xtreme Video this morning, this ridge will weaken in 2 to 3 days. This should cause the cyclone to slow down and turn northward then. Late in
the period a northeastward acceleration is expected ahead of an approaching mid-latitude trough. Track guidance continued to show a substantial spread late in the forecast period, however, there is reasonable agreement in the near-term track of the cyclone. The NHC forecast is close to a consensus of the GFS and ECMWF through day 4 and is a little faster than the GFS and GEFS ensemble mean at day 5.

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There is probably going to be a race between TD Eight and Nine to see which one reaches tropical storm strength first. It looks like Eight could gain tropical storm status first so it would be named Hermine. That likely means that TD Nine would be named Ian. But stay tuned since everything can change!

In the near term, heavy tropical rain is likely to occur over much of the Florida Peninsula with amounts of 3 to 5 inches. The HPC folks are estimating the heaviest rainfall over the next five days to fall in the eastern Gulf of Mexico with 7 to 10 inches possible.

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It always seems to get exciting as we approach the peak in hurricane season, and 2016 is certainly not disappointing.

-Brian-

Tropics Take Center Stage

| August 28, 2016 @ 12:54 pm

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It’s a warm and humid last Sunday of August across Central Alabama. Temperatures are approaching 90F at the noon hour, heading toward highs between 91F-94F. With dewpoints in the lower 70s, heat index values are in the middle and upper 90s.

Skies are partly cloudy and regional radars are mostly quiet. High pressure at the surface and aloft is pretty much putting the kibosh on any showers and storms. A few isolated ones will form over a few lucky spots and continue into the mid-evening hours.

If you find yourself under one, count your lucky stars, then watch out for lightning!

QUICK CHECK ON THE TROPICS

…Gaston is a 105 mph hurricane east of Bermuda. It is drifting WNW but should recurve before affecting the island.

…99L is passing through the Florida Straits this afternoon. A circulation center is evident south of the Florida Keys. Key West NAS has a NE wind at 14 gusting 23 mph. The models believe 99L will become a tropical depression over the southern Gulf of Mexico. The GFS moves it out into the Middle Gulf by late Tuesday before turning it northeast toward the West Coast of the Florida Peninsula by next weekend. That would have little impact on Alabama’s weather, just some rough surf and showers and storms along the Gulf Coast. The European run from last night also depicts a move toward the Big Bend area of Florida. The Canadian does carry it to the Mobile/Pensacola area by Thursday night. It is too early to tell what specific course might occur or how strong it will become. Suffice to say, we will be watching.

LONG TRACK CAPE VERDE STORM IN THE CARDS?

The models are predicting a long track hurricane will move across the Atlantic over the next two weeks. This is the GFS output for Tuesday morning the 13th.
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Output has consistently carried it to the mid-Atlantic Coast, as far south as Jacksonville or up into Virginia. But the morning run of the GFS brings it across the Caribbean and into the GUlf of Mexico. We will also have to pay attention to that possibility.

Depression Eight Forms

| August 28, 2016 @ 10:04 am

A new tropical depression has formed this morning, but those of you watching the tropical Atlantic may be surprised to learn it is NOT the one progressing through the Florida Straits. No, it is not that one, but it is the one that is west of Bermuda headed west.

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There are currently no coastal watches or warnings in effect, but all interests along the Outer Banks of North Carolina should monitor
the progress of this depression. A tropical storm watch may be required for part of this area later today.

At 10:00 am CDT, the center of Tropical Depression Eight was located near latitude 31.5 North, longitude 70.0 West. The depression is moving toward the west near 9 mph. A west-northwestward motion is expected later today and tonight followed by a turn toward the northwest and a decrease in forward speed on Monday. Based on the forecast track, the center of the storm will pass offshore of the Outer Banks of North Carolina on Tuesday.

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Maximum sustained winds are currently near 35 mph with higher gusts. Some strengthening is possible in the next couple of days, and the depression may reach tropical storm strength on Monday. The estimated minimum central pressure based on data from NOAA buoy 41048 is 1009 mb or 29.80 inches.

Convection associated with the area of low pressure located west of Bermuda has increased markedly since 06Z. Given this and the well-defined center shown by an overnight ASCAT pass, advisories are now being initiated on this system as a tropical cyclone (depression). The initial intensity is estimated to be 30 kt based on the latest Dvorak estimates of T2.0/30 kt from TAFB and SAB. An Air Force Reserve Hurricane Hunter aircraft is scheduled to investigate the depression this afternoon.

The environment is currently only marginally conducive for intensification with moderate southeasterly to easterly shear expected to become southwesterly and increase further in 36 to 48 hours. As a result, only modest strengthening is shown in the official forecast, with the depression expected to become a tropical storm in the next day or two. After that time, the global models show the cyclone opening up along a frontal zone well offshore of the northeastern United States. However, there is some disagreement in when this will occur, with the GFS showing the cyclone dissipating in about 3 days, and the ECMWF hanging onto it until around day 5. The NHC forecast compromises on this showing dissipation after day 4, but this timing is quite uncertain.

The depression is currently situated south of a mid-level ridge that extends from the Mid-Atlantic states into the western Atlantic with an initial motion estimate of 280 degrees at 8 knots. The ridge is forecast to break down and shift eastward during the next 2-3 days, which should result in the cyclone gradually turning poleward and then recurving during the next 72 hours. The NHC track forecast is close to a blend of the GFS and ECMWF models through dissipation. This forecast keeps the center of the cyclone east of the Outer Banks of North Carolina, but a tropical storm watch may be needed for that area later today.

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You may be inclined to think that this system is the remnant of Fiona. However, based on an evaluation of satellite imagery and data during the past
few days by NHC, it appears that the remnants of Tropical Storm Fiona are not directly responsible for the genesis of this depression. The Fiona remnants were absorbed into a separate area of pre-existing vorticity, with the current depression developing out of the combined system. As a result, this is considered to be a new tropical cyclone, not a regeneration of a previous tropical cyclone.

The National Hurricane Center (NHC) will issue the next advisory at 5:00 pm EDT.

-Brian-

Invest 99L And Labor Day Weekend

| August 28, 2016 @ 7:04 am

THE HYPE MACHINE: I still say the open tropical wave known as “Invest 99L” is the most publicized disorganized wave in history. The two primary reasons…

*It has been 3,961 days (almost 11 years) since a major hurricane (category three or higher) has made landfall in the U.S… last one was Hurricane Wilma that hit Florida on October 24, 2005. This is now the longest streak (by far) since hurricane records began in 1851. And, no, “Sandy” wasn’t a “major hurricane” by definition when it moved into the Northeast U.S. in 2012; it was a a category one hurricane morphing into a post-tropical storm.

*Social media now allows anyone and everyone to share weather information and computer models to thousands, if not millions. Twitter didn’t exist the last time a hurricane hit Florida. And, there are many weather enthusiasts and zealots that “want some action”, and do their best to “wishcast” a hurricane by finding that one deterministic 300 hour model run that shows the big one coming up on places like Gulf Shores or Panama City Beach.

Many of these weather amateurs are middle school or high school students, that run sites like “Joe Bob’s Weather Center”, with a corresponding Facebook page. They have learned that the most outrageous hurricane forecasts are the ones that get the attention. When they post long range model output that shows a big storm, they also ask, and almost beg, for you to “like and share”. That is the first warning sign you have stumbled upon a clickbait site with no regard for the truth or ethics.

We want young people to be able to have web sites and Facebook pages, but even a 15 year old has to understand they have great power to deceive the public, and need to keep the information they share within the bounds of meteorologically sound advice. There are many things we don’t know, and many things we can’t do. There is no 15 year old running “Joe Bob’s Weather Center” that knows the intensity and track of a tropical cyclone two weeks in advance.

From those of us in the professional enterprise, I am asking you not to click, like, or especially share bogus weather information concerning things like hurricanes and winter storms, despite the temptation. Look for professional meteorologists, especially those with American Meteorological Society certification like the CBM (certified broadcast meteorologist), or CCM (certified consulting meteorologist). You earn these through academic credentials, a review of your professional work by peers, and a rigorous exam. Sure, those with a CBM or CCM can and will be wrong, but I assure you the information is more solid that “Joe Bob’s Weather Center”.

WHAT ABOUT 99L? This morning the wave near the northern coast of Cuba remains disorganized, but is hanging in there. Model output can’t be trusted much since there is no way to initialize the wave, so you see wild output like this (06Z tropical model set)…

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Concerning global models and the ensemble approach (one model using slightly different initial conditions that are all plausible given the past and current set of observations), the GFS has been fairly consistent, suggesting slow development in the eastern Gulf, with a turn to the right over North Florida late this week.

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The reliable European model is trending toward this solution, and seems to be a credible idea. If by chance this is correct, most of the rain and inclement weather associated with the wave (it gets the name Hermine if it becomes a Tropical Storm) will remain south and east of Alabama, and east of places like Gulf Shores and Pensacola.

And, intensity guidance suggests a hurricane is not especially likely…

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But the bottom line is this… at this time nobody knows the final destination and intensity curve of “99L”, or if it will impact the Central Gulf Coast over the Labor Day weekend. Once we finally get an organized system, we will be able to give you a decent holiday weekend forecast for the various coastal locations. Stay tuned.