TropicalAnalystwx13's WunderBlog

Tropical Cyclone Report: Tropical Storm Tony (AL192012)

By: TropicalAnalystwx13, 5:47 AM GMT on December 24, 2012

Note: The Tropical Cyclone Report (TCR) below contains comprehensive, yet easily understandable, information on each tropical cyclone, including synoptic history, causalities and damages, provided by a multitude of different, official resources, and the post-season analysis best track (six-hourly position fixes and intensities). A tropical cyclone is defined as a warm-core, non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters with organized deep convection and a closed surface wind circulation about a well-defined center. These include depressions—cyclones that did not attain 34-knot sustained winds—storms, and hurricanes. It should be noted that, while I strive to produce the most accurate information for the particular cyclone listed below, these reports...including the storms' position and intensity...are not official and are no way associated with the National Hurricane Center or any other branch of the National Oceanic and Atmospheric Administration. Please visit the Atlantic TCR page and the East Pacific TCR page for official reports on any desired cyclone within a particular season.

Note II: During the process of writing these TCRs, I've realized it's a bit redundant to have two to three different bloggers each doing their own. For this reason, for the remaining storms I did not write a TCR on, you can find KoritheMan's over at his blog. Him and I will be doing ours together next season, which should make it easier for both us and the readers.

Tropical Cyclone Report
Tropical Storm Tony (AL192012)
Duration: 22 - 25 October 2012
By: TropicalAnalystwx13
Produced on: 24 December 2012

Tony was a short-lived, yet intense, tropical storm that wandered harmlessly across the central Atlantic in late October 2012.

a. Synoptic History

The formation of Tropical Storm Tony is attributed to a tropical wave that exited the western coast of Africa and into the eastern Atlantic Ocean late on 12 October. While this disturbance exhibited notable cyclonic rotation, an abundance of mid-level dry air and unfavorable wind shear prevented shower and thunderstorm growth. As the wave tracked west-northwest for several days, it continued to encounter unfavorable atmospheric conditions and showed little signs of organization. However, on 19 October, the wave passed under an upper-level trough, which provided a large area of diffluence aloft in the vicinity of the system, which in return allowed for a large area of convection blossom. The wave became vertically aligned with the upper-level low the following day, allowing for wind shear to lower and a low-level circulation to begin forming. Satellite intensity estimates steadily rose over the coming days as the disturbance continued to organize, and it is estimated the system intensified into a tropical depression by 1800 UTC 22 October. The best track positions and intensities are listed in Table 1 at the bottom of this entry (to be added).

The organization of the cyclone did not change much initially, likely due to an upper-level trough to the system's west intruding into the low-level circulation. Several deep bursts of convection occurred during the afternoon hours of 23 October, however, and banding features began organizing as depicted on microwave imagery; this led to the formation of Tropical Storm Tony by 0000 UTC 23 October. As wind shear continued to lower, the small bursts of convection congealed into a large central dense overcast, with upper-level outflow in the western semicircle. A well-defined eye became briefly visible on microwave imagery during the early morning hours of 24 October, despite somewhat meager satellite intensity estimates, and Tony is estimated to have reached its peak intensity of 55 knots at 1200 UTC 24 October. Shortly thereafter, the effects of a nearby cold front and increasingly cool sea surface temperatures began to deteriorate the cyclone's cloud pattern as it tracked northeastward. Tony took on a comma-shaped shape more consistent with an extratropical cyclone and the central dense overcast warmed considerably. A deep burst of convection occurred late on 24 October, but this was soon dismantled and weakened by a combination of wind shear and dry air. The low-level circulation became exposed during the early morning hours of 25 October and remained exposed through 1800 UTC, at which time Tony is thought to have completed extratropical transition. The remnant circulation continued to race northeastward until it was absorbed by a much larger extratropical low on 27 October.

b. Meteorological Statistics

Observations used to determine the peak intensity of Tropical Storm Tony include satellite intensity estimates from the University of Wisconsin's-Cooperative Institute for Meteorological Satellite Studies Advanced Dvorak Technique (UW-CIMSS), the Tropical Analysis and Forecasting Branch (TAFB), and the Satellite Analysis Branch (SAB). Data from the Advanced Microwave Sounding Unit (AMSU) and Advanced Scatterometer (ASCAT) passes were also useful in constructing the best track of Tony.

The estimated peak intensity of 55 knots at 1200 UTC 24 October is based on the presence of a well-defined eye on microwave imagery. It is interesting to note that satellite intensity estimates were much lower than the intensity being given.

c. Casualty and Damage Statistics

There were no reports of damage or casualties associated with Tony.

d. Forecasting and Warning Critique

The formation of Tropical Storm Tony was not well forecast. The disturbance that eventually spawned the named storm was first mentioned in the Personal Tropical Weather Outlook with a low chance (60%) until the time of formation.

Figure 1. Satellite imagery of Tropical Storm Tony at peak intensity.

Tropical Cyclone Reports of 2012

Updated: 4:14 PM GMT on March 23, 2013

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Tropical Cyclone Report: Hurricane Ernesto (AL052012)

By: TropicalAnalystwx13, 5:29 PM GMT on December 22, 2012

Note: The Tropical Cyclone Report (TCR) below contains comprehensive, yet easily understandable, information on each tropical cyclone, including synoptic history, casualities and damages, provided by a multitude of different, official resources, and the post-season analysis best track (six-hourly position fixes and intensities). A tropical cyclone is defined as a warm-core, non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters with organized deep convection and a closed surface wind circulation about a well-defined center. These include depressions—cyclones that did not attain 34-knot sustained winds—storms, and hurricanes. It should be noted that, while I strive to produce the most accurate information for the particular cyclone listed below, these reports...including the storms' position and intensity...are not official and are no way associated with the National Hurricane Center or any other branch of the National Oceanic and Atmospheric Administration. Please visit the Atlantic TCR page and the East Pacific TCR page for official reports on any desired cyclone within a particular season.

Tropical Cyclone Report
Hurricane Ernesto (AL052012)
Duration: 1 - 10 August 2012
By: TropicalAnalystwx13
Produced on: 22 December 2012

Ernesto was a struggling tropical storm across the central Atlantic and upon entrance into the Caribbean Sea. A subsequent decrease in trade winds, however, allowed the system to rapidly intensify into a category 2 hurricane (on the Saffir-Simpson Hurricane Wind Scale) shortly before landfall on the Yucatan Peninsula. Ernesto emerged into the Bay of Campeche the following day, reaching strong tropical storm intensity before rapidly dissipating over the mountainous terrain of Mexico. The remnant mid-level circulation emerged into the eastern Pacific and contributed to the formation of Tropical Storm Hector several days later.

a. Synoptic History

The formation of Hurricane Ernesto is from a series of well-defined tropical waves that left the coast of Africa between 23 July and 28 July. As the waves merged into one, a broad area of low pressure developed, and convection began to increase. Banding features and a significantly better organized structure became apparent on geostationary and microwave imagery on 30 July, and it is estimated the system became a tropical depression the following day at 1200 UTC, situated several hundred miles west-southwest of the Leeward Islands. The best track positions and intensities are listed in Table 1 at the bottom of this entry (to be added).

After formation, the depression moved rapidly westward, attributed to unusually strong trade winds on the southern side of an unusually strong Bermuda high, and failed to organize initially. In fact, the low-level circulation became exposed to view late on 1 August and there are doubts the center was closed at that time; however, for continuity, the depression was not classified as a remnant area of low pressure. Two other factors including the disorganized appearance of the system after genesis include strong northwesterly wind shear produced from a large upper-level low in the central Atlantic and dry mid-level air from Africa. Regardless, as a mid-level trough passed to the north of the Caribbean Islands on 2 August, Ernesto slowed slightly, allowing for increased and organized convection. Satellite imagery and intensity estimates support the depression's intensification into Tropical Storm Ernesto around 1200 UTC 2 August and a recon flight later that afternoon revealed 45 knot sustained winds. A subsequent increase in wind shear and dry air once again caused a decrease in organization, and the system weakened slightly as it passed into the eastern Caribbean Sea, though tropical storm-force winds were still reported on the islands of St. Lucia and Barbados.

After entering the eastern Caribbean, the cloud pattern associated with Ernesto organized tremendously. A central dense overcast, composed of cloud-tops colder than -80°C, formed atop the low-level circulation, and an upper-level anticyclone formed, resulting in astounding outflow in all four directions. Despite satellite intensity estimates of near or over the hurricane threshold, data from an Air Force Reserve Hurricane Hunter aircraft indicated that Ernesto had not intensified at all, and actually began to fall apart as it entered the central Caribbean. On the afternoon of 5 August, convection became much less organized and the low-level center became exposed and open. For continuity, once again, Ernesto remained a tropical cyclone. The forward motion of the disheveled cyclone slowed the following day, and in response to a sharp increase in ocean heat content, Ernesto began to steadily, if not rapidly, intensify. A large central dense overcast and banding features developing once again, and data from an Air Force Reserve Hurricane Hunter aircraft reveals Ernesto became a minimal hurricane by 1800 UTC 7 August.

As the cyclone moved westward to west-northwestward, further intensification occurred. An eye became visible on Dvorak satellite imagery around 0000 UTC 8 August, at which time Ernesto contained maximum sustained winds of 80 knots. An hour later, the system made landfall just south of Chetumal, Mexico, followed by a second landfall roughly two hours later, near Majahual, Mexico. Despite this, Ernesto did not weaken. In fact, as a result of land friction, the system intensified and a well-defined eye became apparent on all forms of geostationary imagery, leading to the system's peak intensity of 90 knots around 0600 UTC 8 August; this is supported by land observations and satellite intensity estimates. After its second landfall, the hurricane quickly weakened and became a tropical storm once again around 1200 UTC 8 August.

The cyclone entered the Bay of Campeche around 0000 UTC 9 August, where slow intensification took place. Ernesto was initially forecast to became a minimal hurricane before its final landfall, but due to the southwesterly motion in the southern Gulf of Mexico, induced by a developing mid-level ridge over the Gulf Coast states, the system intensified and reached a secondary peak intensity of 60 knots before coming ashore Coatzacoalcos, Mexico at 1600 UTC 9 August. Ernesto quickly weakened as it moved inland, becoming a tropical depression around 0600 UTC, and dissipating by 1200 UTC 10 August. The remnant mid-level circulation, however, continued westward into the eastern Pacific basin, where it combined with a surface trough to produce Tropical Storm Hector by early on 11 August.

b. Meteorological Statistics

Observations in Hurricane Ernesto include data from numerous flights of the U.S. Air Force Reserve Hurricane Hunters. Satellite intensity estimates from the University of Wisconsin's-Cooperative Institute for Meteorological Satellite Studies Advanced Dvorak Technique (UW-CIMSS), the Tropical Analysis and Forecasting Branch (TAFB), and the Satellite Analysis Branch (SAB); data from the Advanced Microwave Sounding Unit (AMSU) and Advanced Scatterometer (ASCAT) passes were all also useful in constructing the best track of Ernesto.

The estimated peak intensity of 90 knots with a minimum barometric pressure of 973 millibars around 0600 UTC 8 August is based on satellite intensity estimates of 77 knots from SAB and 90 knots from TAFB, at 0000 UTC and 0300 UTC, respectively, and a plethora of land observations. A storm chaser near the eye of Ernesto reported a minimum pressure of 975 millibars with 15 knot sustained winds shortly before 0600 UTC, while an automated station reported a pressure of 979 millibars a few hours previous. It is assumed Ernesto continued to intensify through 0600 UTC before land friction subsided and the circulation began to weaken over land.

c. Casualty and Damage Statistics

Ernesto is attributed to twelve fatalities—seven direct and five indirect. Two fishermen drowned in Tabasco, Mexico, while three members of a family were killed when a tree landed on their pickup truck in Veracruz. Also in Veracruz, a teenage girl died after she was swept away with her car, and a 62 year old man was struck and killed by a lightning bolt. The remaining deaths occurred to storm-related traffic incidents.

Ernesto is thought to have caused at least $252 million (USD) in damage. This damage estimate includes $7.2 million in Campeche, $51.9 million in Chiapas, $5.4 million in Guerrero, $81.6 million in Oaxaca, $9.5 million in Tabasco, $12.7 million in Quintana Roo, $77 million in Veracruz, and $6.9 million in Yucatan.

No damage was reported in the Lesser Antilles in association with Ernesto.

d. Forecasting and Warning Critique

The genesis of Ernesto was generally well forecast. The disturbance that spawned the hurricane was first mentioned in the Personal Tropical Weather Outlook (PTWO), with a low chance (<30%) of tropical cyclone formation within 48 hours, 60 hours before formation. These percentages were raised to medium (30-50%) about 24 hours before formation, and to the high category about 18 hours before genesis.

Figure 1. Satellite imagery of Hurricane Ernesto at peak intensity.

Tropical Cyclone Reports of 2012

Updated: 5:41 PM GMT on December 22, 2012

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Tropical Cyclone Report: Tropical Storm Alberto (AL012012)

By: TropicalAnalystwx13, 1:35 AM GMT on December 22, 2012

Note: The Tropical Cyclone Report (TCR) below contains comprehensive, yet easily understandable, information on each tropical cyclone, including synoptic history, casualities and damages, provided by a multitude of different, official resources, and the post-season analysis best track (six-hourly position fixes and intensities). A tropical cyclone is defined as a warm-core, non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters with organized deep convection and a closed surface wind circulation about a well-defined center. These include depressions—cyclones that did not attain 34-knot sustained winds—storms, and hurricanes. It should be noted that, while I strive to produce the most accurate information for the particular cyclone listed below, these reports...including the storms' position and intensity...are not official and are no way associated with the National Hurricane Center or any other branch of the National Oceanic and Atmospheric Administration. Please visit the Atlantic TCR page and the East Pacific TCR page for official reports on any desired cyclone within a particular season.

Tropical Cyclone Report
Tropical Storm Alberto (AL012012)
Duration: 19 May – 22 May 2012
By: TropicalAnalystwx13
Produced on: 21 December 2012

Tropical Storm Alberto was the first named storm of the 2012 Atlantic hurricane season and one that produced slight wave increases along the Southeast United States coastline, leading to several ocean rescues. Alberto was the first named storm to form in May since Tropical Storm Arthur in 2008 and the earliest-forming tropical cyclone since Tropical Storm Ana in 2003. The combination of Alberto and Tropical Storm Aletta, in the East Pacific, led to the first occurrence where both basins recorded their first named storm before the start of their respective hurricane seasons.

a. Synoptic History

The formation of Tropical Storm Alberto began on 10 May. At this time, water vapor imagery revealed a well-defined, upper-level, cold-core area of low pressure across Arizona and New Mexico. This low organized as it crossed into western Texas, but was subsequently absorbed into a cold front on 12 May. As the front moved eastward, it stalled across the Southeast United States and into the Mid-Atlantic, where thunderstorms produced a few isolated tornadoes. While the aforementioned low dissipated, a new area of low pressure formed across central North Carolina on 17 May, and moved off the coast by the following day. Embedded within an environment characterized by warm sea surface temperatures and marginally favorable wind shear, the low pressure area began to consolidate, and a small area of shower and thunderstorm activity formed atop the center. Banding features became more prominent in association with the disturbance, and it is estimated that the system became a tropical storm by 1200 UTC 19 May, situated roughly 115 miles east-southeast of Wilmington, North Carolina. The best track positions and intensities are listed in Table 1 at the bottom of this entry (to be added).

A large, mid-level area of high pressure over the Northeast United States initially caused Alberto to drift southwesterly. As this drift occurred, the system passed over two ships which recorded maximum sustained winds of 50 knots and 65 knots, separately, around 0000 UTC; the estimated peak of 55 knots is a blend of the two. A subsequent increase in continental dry air, however, prevented any further intensification, and Alberto began a steady weakening trend. A deepening mid- to upper-level trough across the southeastern states caused the system to turn southeastward, eastward, and eventually northeastward out to sea, while remaining minimal tropical storm intensity. Without the thermal energy of the sea surface temperatures within the Gulf Stream, strong wind shear from the aforementioned trough stripped Alberto of all deep convection, and the system weakened to a tropical depression by 0600 UTC 22 May. Within the next six hours, after lacking organized, deep convection for a sufficient amount of time, Alberto degenered into a non-convective remnant area of low pressure, while located over a hundred miles east-southeast of Cape Hatteras, North Carolina. The remnant circulation accelerated rapidly towards the northeast and dissipated the following day several hundred miles south of Newfoundland.

b. Meteorological Statistics

Observations in Tropical Storm Alberto include data from 2 flights of the U.S. Air Force Reserve Hurricane Hunters. Satellite intensity estimates from the University of Wisconsin's-Cooperative Institute for Meteorological Satellite Studies Advanced Dvorak Technique (UW-CIMSS), the Tropical Analysis and Forecasting Branch (TAFB), and the Satellite Analysis Branch (SAB), data from the Advanced Microwave Sounding Unit (AMSU) and Advanced Scatterometer (ASCAT) passes were all also useful in constructing the best track of Alberto.

The estimated peak intensity of 55 knots around 0000 UTC 20 May with Alberto is based on two ship reports on the afternoon of 19 May. 65 knot sustained winds were reported with the ship Sea-Land Champion at 2000 UTC and 50 knot sustained winds were reported with an unnamed ship roughly an hour and a half later. The aforementioned peak intensity value is a blend of the two.

c. Casualty and Damage Statistics

There were no reports of damage or casualties associated with Alberto.

d. Forecasting and Warning Critique

N/A.

Personal Tropical Weather Outlooks (TWOs) were not produced for any tropical cyclone until 1 August.

Figure 1. Satellite imagery of Tropical Storm Alberto at peak intensity.

Tropical Cyclone Reports of 2012

Updated: 3:58 PM GMT on December 22, 2012

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91L a threat to develop, Bopha a threat for destruction; End of Hurricane Season 2012

By: TropicalAnalystwx13, 2:22 AM GMT on December 01, 2012

Yoga Berra, a famous former American Major League Baseball catcher, once stated, "It ain't over 'til it's over", and that saying definitely applies to the Atlantic hurricane season today. On the final official night of the 2012 season, the National Hurricane Center is monitoring a small area of low pressure in the central Atlantic. With a 30% chance of tropical or subtropical cyclone development for the time being, the disturbance is not terribly disorganized nor organized on geostationary imagery. The system as a whole has become slightly less organized over the past few hours with meager convection, but this is expected considering 91L, dubbed by the National Hurricane Center, is entering diurnal minimum and is embedded within a region of high vertical wind shear. As of the 0Z ATCF update, the invest contained maximum sustained winds of 30 mph and a minimum barometric pressure of 1012 millibars; it was moving north at 6 mph.


Figure 1. A visible and infrared satellite loop of Invest 91L.

Forecast for 91L
Invest 91L is currently embedded in a high wind shear environment and atop sea surface temperatures well below the 26 °C threshold needed to sustain a fully-tropical cyclone. In fact, the 0Z SHIPS analyzed nearly 60 knots of wind shear atop the disturbance's circulation. While this would typically rip a storm apart, the core of 91L is more subtropical in nature than tropical, and subtropical cyclones are more adapt to sustain high wind shear, cooler sea surface temperatures, and a more stable environment; this is why they form in areas tropical cyclones usually do not. Infrared imagery reveals 91L has a notable low-level circulation, but there is a high chance it is not closed. There have been no recent Advanced Scatterometer passes to evaluate the structure of the center of 91L. Nonetheless, as it drifts slowly northward or even meanders over the coming days, wind shear is expected to lower to near 30 knots. Sea surface temperatures are also expected to cool to values near 22 °C. The system has a relatively moist environment, with added moisture from a frontal zone to its northwest.

Even a subtropical cyclone cannot withstand sea surface temperatures below 24 °C for long periods of time. As 91L drifts slowly northward it will likely acquire a more tropical appearance but rapidly transition into an extratropical cyclone by 96 hours. All things considered, I'd give the system a Medium chance, 50%, of becoming a tropical or subtropical cyclone during the next 48 hours. As aforementioned, the National Hurricane Center gave the disturbance a Medium chance, 30%, of becoming a named cyclone during the next 48 hours. Their new probabilities will be likely be issued sometime in the morning in the form of a Special Tropical Weather Outlook.


Figure 2. A infrared satellite image of Typhoon Bopha.

Typhoon Bopha a serious threat
In the West Pacific, a basin historically proven to produce several storms in the month of December, spins Typhoon Bopha, a powerful Category 4-equivalent that poses a serious threat to land. With maximum sustained winds pegged at 135 mph, Bopha has residents across the Philippines scrambling to prepare for a potential impact on Tuesday. An interesting fact about Bopha is that its current position is pinned at 142 °E 4.7 °N. That's a meager 4.7 °N of the equator, and 1.1 °N north of its formation point! It's rare to see a storm form below 10 °N, much less 5 °N, and this makes Bopha one of the farthest-south forming tropical cyclones ever recorded in the northern hemisphere.

2012 Atlantic hurricane season comes to a close
The never-ending, deadly, destructive, and strange 2012 Atlantic hurricane season has finally come to an end. However, it will not soon be forgotten. The storm many people will remember for years to come is Superstorm Sandy, a beast of a hurricane that caused widespread destruction and fatalities from Jamaica and to Canada. However, the season as whole was destructive. Four tropical cyclones, including one Category 1 hurricane, struck the United States during the 2012 season: first Beryl, followed by Debby, Isaac, and finally Sandy. Tropical Storm Beryl was a system that became the strongest off-season tropical cyclone on record to hit the United States. While Debby was a borderline tropical depression/tropical storm at landfall on the Florida Peninsula, it is remembered for the rainfall totals well over a foot it produced across the region, as well as being the earliest fourth named storm on record. The first hurricane to make landfall in the U.S., Isaac, was relatively disorganized for much of its life. However, it brought a large storm surge to the coastline of Louisiana, devastating low-lying communities while also proving that the multi-billion system placed in New Orleans after Katrina will indeed protect the city from a minimal hurricane. But of course, Sandy, was the grand prize of the season, with a price tag of $65 billion dollars, which is likely to surpass $100 billion according to Colorado State University, and at least 125 USA deaths (at least 199 overall).

What makes the 2012 Atlantic hurricane season so strange, however, is not the number of landfalls and where they occurred, but the low number of intense storms in the deep tropics and the lack of intense hurricanes overall. While the season produced ten hurricanes, the sixth highest total in recorded history, only one of those ten, Michael, became a major hurricane—a Category 3 or higher on the Saffir–Simpson Hurricane Wind Scale. This can be attributed to the presence of unusually dry and stable air across much of the Atlantic throughout the season. And this can in turn be attributed to below average vertical instability–a measure of the difference of temperature between the lower atmosphere and the upper atmosphere–that has plagued the Atlantic basin for two years now. Despite the low number of intense storms, the 2012 season produced nineteen of them, making it the third most active on record (tied with 1887, 1995, 2010, and 2011).

Records and near-records

May 2012: Highest number of named storms in that particular month, tied with 1887.

Hurricane Chris: Farthest north forming hurricane before the month of August.

Tropical Storm Debby: 14th highest tornado-producing tropical cyclone.

August 2012: Highest number of named storms in that particular month, tied with 2004 and September 2007/2010.

Tropical Storm Florence: 2nd earliest formation of the 6th tropical storm of a particular hurricane season on record.

Tropical Storm Joyce: 2nd earliest formation of the 10th tropical storm of a particular hurricane season on record.

Hurricane Kirk: 2nd earliest formation of the 11th tropical storm of a particular hurricane season on record.

Hurricane Leslie: 2nd earliest formation of the 12th tropical storm of a particular hurricane season on record.

Hurricane Michael: 2nd earliest formation of the 13th tropical storm of a particular hurricane season on record.

Hurricane Nadine: 5th longest-lived tropical cyclone on record.

Hurricane Sandy: Largest known Atlantic hurricane on record by gale diameter.

Hurricane Sandy: Second costliest Atlantic hurricane on record.

Tropical Storm Tony: 2nd earliest formation of the 19th tropical storm of a particular hurricane season on record.

TropicalAnalystwx13

Tropical Cyclones of 2012 Tropical Weather

Updated: 9:52 PM GMT on December 07, 2012

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About TropicalAnalystwx13

Teenager. Weather aficionado. Soccer fan. Realist. Posts subject to sarcasm. Goal: National Hurricane Center.