Dienstag, 1. Juli 2014

Tropical Depression One Forms off the Coast of East Florida






The Atlantic's first tropical depression of 2014 is here, as Tropical Depression One finally formed at 11 pm EDT Monday evening from disturbance 91L. TD 1 was drifting southwest at 2 mph towards the east coast of Central Florida early Tuesday morning. Long-range radar out of Melbourne, Florida on Tuesday morning showed that bands of heavy rain from TD 1 were affecting the Northwest Bahamas, and sustained winds of 33 mph gusting to 36 mph were observed at Settlement Point in the Northwest Bahama Islands at 2 am EDT.






Satellite loops showed heavy thunderstorms were limited to the south side of TD 1's center of circulation, and were slowly increasing in intensity and areal coverage. The counter-clockwise circulation of an upper level high pressure over Florida was bringing northerly winds over TD 1 at high altitude, and these winds were creating moderate wind shear of 10 - 15 knots. Water vapor satellite loops showed very dry air to the north of TD 1, and the northerly winds were driving this dry air in the heart of the storm, interfering with development, and keeping any heavy thunderstorms from developing on the north side of the circulation. The Air Force Hurricane Hunters will investigate TD 1 on Tuesday morning, and the NOAA jet is scheduled to fly Tuesday afternoon.



Samstag, 21. Juni 2014

Atlantic Hurricane Outlook for the Remainder of June

There were no tropical cyclones anywhere in the world on Friday, and none of the reliable models for forecasting tropical cyclone genesis in the Atlantic (European, GFS, and UKMET) is predicting development over the coming five days. There is a tropical disturbance off the east coast of Florida that radar out of Melbourne, Florida shows some spin to. However, satellite loops show the area of heavy thunderstorms is very limited, and there is a lot of dry air interfering with thunderstorm development. Wind shear is a moderate 10 knots. In their 8 am EDT Friday Tropical Weather Outlook, NHC gave the disturbance 2-day and 5-day development odds of 10%. The disturbance will likely head northeast out to sea over the weekend.




Hurricane Forecast for the Remainder of June

Vertical wind shear is predicted to be very high over most of the tropical Atlantic the remainder of June, reducing the odds of tropical storm formation. With the active thunderstorm area of the MJO predicted to remain over the Pacific Ocean the rest of June, this will favor dry, sinking air over the Atlantic, further discouraging tropical storms from forming. 

Sea surface temperatures (SSTs), which are close to average over the Caribbean (an anomaly of +0.1°F) and cooler than average over the Gulf of Mexico (an anomaly of -0.2°F) will do no favors for any potential June tropical storms that try to form. If development does occur in June, the most likely location would be off the east coast of Florida, between the Bahamas and Bermuda, where SSTs are slightly above average and wind shear will be lower. Storms that form in this region are typically only a threat to Bermuda.

Since the active hurricane period we are in began in 1995, six of the nineteen years (32%) did not have a named storm develop in June. I give an 80% chance that 2014 will join that list. The most recent year without a June named storm developing was the El Niño year of 2009. The highest number of named storms for the month is three, which occurred in 1936 and 1968. There were two June named storms in 2013, Andrea and Barry.

Donnerstag, 29. Mai 2014

Temblor Punta Cana - Mona Canal

El temblor fue de 6 grados y se produjeron cinco réplicas.

 

 El Instituto Sismológico de la Universidad Autónoma de Santo Domingo (UASD) informó que el temblor que se sintiò en gran parte del paìs ayer fue de 6 grados y que el epicentro se produjo en el Canal de la Mona, a 18 kilòmetros de Punta Cana.

Hasta ayer en la noche no se habían reportado daños materiales y tampoco humano, según el Centro de Operaciones de Emergencia (COE), organismo que llamó a la calma.

En un reporte preliminar, el COE informó, además, que el sismo se sintió en las provincias de La Altagracia, El Seibo, Hato Mayor, La Romana, San Pedro de Macorís y el Gran Santo Domingo.

En su primera informaciòn la pàgina web del Servicio Geològico de Estados Unidos dio a conocer que el movimiento telùrico fue de 5.3 grados y màs tarde corrigiò que fue de 5.8 grados.

Entrevistado vìa telefònica, Andrés Moreta, del Sismològico de la UASD, informò que el epicentro del temblor se produjo en la latitud 18.5 y longitude 68.2.

Reporte de la agencia EFE indican que el sismo se sintiò tambièn en la zona metropolitana de San Juan, Puerto Rico.








Cinco réplicas ayer 

Cinco réplicas se han registrado del sismo de 6 grados en la escala de Richter que se produjo en la tarde de hoy próximo a la provincia La Altagracia y que se sintió en gran parte del país.

Los movimientos telúricos han sido dos de 3.6, otro de 3.3, uno de 3.4 y de 3.0, según Andrés Moreta, analista de datos sísmico del Centro Nacional de Sismología (antiguo Instituto Sismológico de la Universidad Autónoma de Santo Domingo (UASD)

El temblor de 6 grados se produjo a las 5:15 de la tarde de hoy, en el Canal de la Mona y a 31 kilómetros de Boca de Yuma, en La Altagravcia, sin que se hayan reportado daños.

Moreta informó que veinte minutos después se registró una réplica de 3.6 grados en la latitud 17.93 y longitud 68.35, a unos 46 kilómetros al sureste de Mano Juan, en la Isla Saona, con epicentro en el mar Caribe y con una profundidad de 77 kilómetros

La segunda réplica fue a las 6:29 de la tarde, de 3.3 grados a 42 kilómetros al sureste de Punta Cana, también con epicentro en el Canal de la Mona y con una profundidad de 100 kilómetros.

El tercer temblor se produjo a las 6: 58 de la tarde, de 3 grados, con epicentro en el océano Atlántico y a 32 kilómetros al noreste de Las Terrenas. Otro de los eventos sísmicos fue a las 7:43 de la tarde, de 3.4 y al sureste de Mano Juan, en el mar Caribe, con una profundidad de 90 kilómetros.

A las 9:12 de la noche también se registró movimiento telúrico, de 3.6 en el mar Caribe y a 40 kilómetros de Mano Juan. Este tuvo una profundidad de 95 kilómetros.

Freitag, 23. Mai 2014

NOAA Predicts a Quiet Atlantic Hurricane Season: 8 - 13 Named Storms

The Atlantic hurricane season starts in just over a week, and long-range models are already pointing to the possibility that the Western Caribbean will be capable of brewing the season's first "Invest" during the first week of June. But so far, the major hurricane forecasting groups are not impressed with this season's potential to be an active one. They are calling for 2014 to be a below average to near-average year for the Atlantic.

NOAA's prediction, issued this Thursday morning, forecasts a 50% chance of a below-normal season, a 40% chance of an near-normal season, and only a 10% chance of an above-normal season. They predict a 70% chance that there will be 8 - 13 named storms, 3 - 6 hurricanes, and 1 - 2 major hurricanes, with an Accumulated Cyclone Energy (ACE) 40% - 100% of the median. If we take the midpoint of these numbers, NOAA is calling for 10.5 named storms, 4.5 hurricanes, 1.5 major hurricanes, and an ACE index 70% of normal. This is below the 1981 - 2010 average of 12 named storms, 6 hurricanes, and 3 major hurricanes. Hurricane seasons during the active hurricane period 1995 - 2013 have averaged 15 named storms, 8 hurricanes, and 4 major hurricanes, with an ACE index 151% of the median.






 NOAA cites three key factors influencing their forecast for a below-normal to near-normal hurricane season:

1) An El Niño event is predicted for the summer and fall, which is expected to bring strong wind shear-inducing upper-level winds over the Tropical Atlantic. Vertical wind shear during the past 30 days was stronger than average across much of the Main Development Region (MDR) for hurricanes, from the coast of Africa to the Caribbean. Sinking air at mid-and upper-levels was also stronger than average. The development of El Niño would mean a likely continuation of these non-conducive conditions, and both versions of NOAA's long-range CFS model are predicting enhanced vertical wind shear across the western MDR during August-September-October 2014. Strong vertical wind shear and sinking motion, linked to a rare jet stream pattern of record strength, were key suppressing factors during the unexpectedly quiet 2013 Atlantic hurricane season.

2) Sea Surface Temperatures (SSTs) are near average in the MDR. Many long-range dynamical computer forecast models are predicting that SSTs in the MDR will remain near- or below-average throughout the hurricane season.

3) We are in an active hurricane period that began in 1995, and this positive phase of the Atlantic Multi-decadal Oscillation (AMO) may act to keep hurricane activity higher than it would otherwise be.




Colorado State predicts a below-average hurricane season: 9 named storms

A below-average Atlantic hurricane season is on tap for 2014, according to the seasonal hurricane forecast issued April 10 by Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU). The CSU team is calling for 9 named storms, 3 hurricanes, and 1 intense hurricane, and an Accumulated Cyclone Energy (ACE) of 55, a little more than half of average. The forecast calls for a below-average chance of a major hurricane hitting the U.S., both along the East Coast (20% chance, 31% chance is average) and the Gulf Coast (19% chance, 30% chance is average). The risk of a major hurricane in the Caribbean is also below average, at 28% (42% is average.)







 CSU's Analogue years: 2002, 1997, 1965, 1963, and 1957
The CSU team picked five previous years when atmospheric and oceanic conditions were similar to what they expect for this year: moderate El Niño conditions, neutral to slightly cool sea surface temperatures in the tropical Atlantic, and a positive phase of the Atlantic Multi-decadal Oscillation (AMO). Those five years were 2002, which featured two major hurricanes that got their names retired: Lili and Isidore; 1997, a quiet year with only 8 named storms and 3 hurricanes; 1965, a quiet year with only 6 named storms (but one of these was a real doozy--Hurricane Betsy, which struck Louisiana as a Category 3 storm;) 1963, with 9 named storms and 7 hurricanes, including Cuba's deadliest hurricane of all-time: Hurricane Flora (8,000 killed); and 1957, a below-average year with 8 named storms and 2 major hurricanes, including June's deadly Hurricane Audrey, which was re-analyzed as a Category 3 storm this year. The average activity during these five analogue years was 9 named storms, 4 hurricanes, and 2 major hurricanes. The CSU team will issue an updated forecast on Monday, June 2, 2014.







 TSR predicts a near-average hurricane season: 12 named storms

The April 7 forecast for the 2014 Atlantic hurricane season made by British private forecasting firm Tropical Storm Risk, Inc. (TSR) calls for a near-average season with 12 named storms, 5 hurricanes, 2 intense hurricanes, and an Accumulated Cyclone Energy (ACE) of 75. The long-term averages for the past 64 years are 11 named storms, 6 hurricanes, 3 intense hurricanes, and an ACE of 102. TSR rates their skill level as modest for these April forecasts: 7 - 15% higher than a "no-skill" forecast made using climatology. They project that 3 named storms will hit the U.S., with 1 of these being a hurricane. The averages from the 1950-2013 climatology are 3 named storms and 1 hurricane hitting the United States. TSR rates their skill at making these April forecasts for U.S. landfalls just 5% - 8% higher than a "no-skill" forecast made using climatology. In the Lesser Antilles Islands of the Caribbean, TSR projects one named storm and no hurricanes in 2014. Climatology is 1.1 named storms and 0.5 hurricanes.

TSR's two predictors for their statistical model are the forecast July - September trade wind speeds over the Caribbean and tropical North Atlantic, and the forecast August - September 2013 sea surface temperatures (SSTs) in the tropical North Atlantic Main Development Region (MDR) for hurricanes. Their model is calling for SSTs 0.32°C below average and trade winds 1 m/s stronger than average during these periods; both of these factors should act to decrease hurricane and tropical storm activity. The July-September 2014 trade wind prediction is based on an expectation of moderate El Niño conditions in August-September 2014. TSR will issue an updated forecast on May 27, 2014.


Penn State predicts a below-average hurricane season: 9 named storms
A statistical model by Penn State's Michael Mann, alumnus Michael Kozar, and researcher Sonya Miller is calling for a quiet Atlantic hurricane season with 9.3 named storms, plus or minus 3 storms. Their prediction was made using statistics of how past hurricane seasons have behaved in response to sea surface temperatures (SSTs), the El Niño/La Niña oscillation, the North Atlantic Oscillation (NAO), and other factors. The statistical model assumes that the mid-May 2014 0.29°C above average SSTs in the MDR will persist throughout hurricane season, a moderate El Niño will be in place, and the North Atlantic Oscillation (NAO) will be near average.

The PSU team has been making Atlantic hurricane season forecasts since 2007, and these predictions have done pretty well, except for in 2012, when an expected El Niño did not materialize. They were the only major forecast group that issued a successful 2013 Atlantic hurricane season forecast.

2007 prediction: 15 named storms, Actual: 15
2009 prediction: 12.5, named storms, Actual: 9
2010 prediction: 23 named storms, Actual: 19
2011 prediction: 16 named storms, Actual: 19
2012 prediction: 10.5 named storms, Actual: 19
2013 prediction: 16 named storms, Actual: 14


UK Met Office predicts a below-average hurricane season: 10 named storms
The UKMET office forecast for the 2014 Atlantic hurricane season, issued May 16, calls for below-average activity, with 10 named storms, 6 hurricanes, and an ACE index of 84. In contrast to the statistical models relied upon by CSU, TSR, PSU, and NOAA, the UKMET forecast is done strictly using two dynamical global seasonal prediction systems: the Met Office GloSea5 system and ECMWF system 4. Their forecasts for the past two years have not verified well:

2012 prediction: 10 named storms, ACE index of 90; Actual: 19 named storms, ACE index of 123
2013 prediction: 14 named storms, 9 hurricanes, ACE index of 130; Actual: 14 named storms, 2 hurricanes, ACE index of 31

NOAA predicts an above-normal or near-normal Eastern Pacific hurricane season: 17 named storms
As is usually the case when an El Niño event is threatening, NOAA's pre-season prediction for the Eastern Pacific hurricane season, issued on May 22, is calling for an active season. NOAA expects there to be 14 - 20 named storms, 7 - 11 hurricanes, 3 - 6 major hurricanes, and an ACE index 95% - 160% of the median. The mid-point of these ranges gives us a forecast for 17 named storms, 9 hurricanes, and 4.5 major hurricanes, with an ACE index 127.5% of average. The 1981 - 2010 averages for the Eastern Pacific hurricane season are 15 named storms, 8 hurricanes, and 4 major hurricanes. The outlook calls for a 50% chance of an above-normal season, a 40% chance of a near-normal season, and a 10% chance of a below-normal season. El Niño decreases the vertical wind shear over the tropical Eastern Pacific, favoring the development of more and stronger tropical cyclones. Since 1995 the Eastern Pacific has been in an era of low activity for hurricanes, but this pattern will be offset in 2014 by the impacts of El Niño.

NOAA predicts a near-normal or above-normal Central Pacific hurricane season
NOAA's pre-season prediction for the Central Pacific hurricane season, issued on May 22, calls for a near-normal or above-normal season, with 4 -7 tropical cyclones. An average season has 4 - 5 tropical cyclones, which include tropical depressions, tropical storms, and hurricanes. The outlook calls for a 40% chance of a near-normal season, a 40% chance of an above-normal season, and a 20% chance of a below-normal season. El Niño decreases the vertical wind shear over the tropical central Pacific, favoring the development of more and stronger tropical cyclones. Since 1995 the central Pacific has been in an era of low activity for hurricanes, but this pattern will be offset in 2014 by the impacts of El Niño. Hawaii is the primary land area affected by Central Pacific tropical cyclones.

Even a quiet hurricane season can be devastating
Quiet hurricane seasons with below-average activity can still produce major hurricanes that cause massive devastation. The five seasons that CSU lists as analogue years for 2014 produced five hurricanes that had their names retired, including one that killed 8,000 people in Cuba (Flora of 1963) and one that killed over 400 people in Texas and Louisiana (Audrey of 1957.) Even if an El Niño does develop this year, that doesn't mean it will be a quiet season. Recall the El Niño year of 2004, when four major hurricanes pounded the U.S.--Ivan, Charlie, Jeanne, and Frances. Those of you in Hurricane Alley should prepare for the 2014 season the same way you would for a predicted hyperactive season, and be ready for the Storm of the Century to hit your location. 


Jeff Masters