Weather456's Tropical Weather Blog

Christmas Gift Ideas

By: Weather456, 6:21 PM GMT on November 28, 2009

Good day to all, long time I have not blog with you guys since I have been more than preoccupied with personal engagements. I decided to update my blog today with some Christmas gift ideas mainly intended for those young folks growing up with an interest in weather. These gifts are the ones I find to be the most economic in these times while at the same time providing rewards long after purchase.

A Personal Weather Station

This is probably the best gift you can give a young weather enthusiast. They come in a variety of shapes, sizes and function. My best advice is to buy a weather station that can measure the basics such as temperature, barometric pressure, humidity, wind and rainfall. Additional functions such as UV, sunshine recorder and wireless are options. I do have a personal weather station that I bought for about 140 USD that comes with two thermometers, a wind vane, anemometer, barometer, rain gauge, and main display unit. The Honeywell TE831W-2 Wireless Weather Station with Computer Interface is the one I would recommend to anyone since at 140 USD, you get everything, even wireless and the ability to upload the information to your computer and Weatherunderground via a software called Weather Display. The weather station is well built and the batteries last 12-18 months. I have little problems with this piece of fun. You can buy this station at Amazon.com and/or Ambient Weather. You can find even more brands like Lacrosse, Oregon and Davis Instruments, which are a bit more expensive at the latter website.

Divine Wind

Imagine standing at the center of a Roman coliseum that is 20 miles across, with walls that soar 10 miles into the sky, towering walls with cascades of ice crystals falling along its brilliantly white surface. That's what it's like to stand in the eye of a hurricane. In Divine Wind, Kerry Emanuel, one of the world's leading authorities on hurricanes, gives us an engaging account of these awe-inspiring meteorological events, revealing how hurricanes and typhoons have literally altered human history, thwarting military incursions and changing the course of explorations. Offering an account of the physics of the tropical atmosphere, the author explains how such benign climates give rise to the most powerful storms in the world and tells what modern science has learned about them. Interwoven with this scientific account are descriptions of some of the most important hurricanes in history and relevant works of art and literature. For instance, he describes the 17th century hurricane that likely inspired Shakespeare's The Tempest and that led to the British colonization of Bermuda. We also read about the Galveston Hurricane of 1900, by far the worst natural calamity in U.S. history, with a death toll between 8,000 and 12,000 that exceeded the San Francisco earthquake, the Johnstown Flood, and the Okeechobee Hurricane combined. Boasting more than one hundred colour illustrations, from ultra-modern Doppler imagery to classic paintings by Winslow Homer, Divine Wind captures the profound effects that hurricanes have had on humanity. It is a fascinating blend of history, science, and art will appeal to weather junkies, science buffs, and everyone who read Isaac's Storm.

I will have an update hopefully on Monday or Tuesday, where I will present a summary of my forecast performance for the 2009 Hurricane Season, lessons learn, why the season was so inactive and what we may see during the 2010 Hurricane Season.

Weather456

Shaken but not stirred

By: Weather456, 2:47 PM GMT on November 15, 2009

Tropical Update

The tropics remain benign this November Sunday, which is typical going into the last 2 weeks of hurricane season, but there a couple of features that stand out in the tropical Atlantic this morning.

First, the remnant of Ida is churning across the Western Atlantic bringing gusty winds and shower activity to Bermuda with the trailing frontal boundary draped southwest to Hispaniola, Puerto Rico and the extreme northern Leeward Islands. This system is expected to linger some over the next few days, gradually making its way southeastward as a strong blocking ridge develops across the Northwest Atlantic. This should limit any movement of ex-Ida into the mid-latitude westerlies, which is a recipe for subtropical development. The models agree that some of the energy will eventually become trapped but only one model – the CMC – develops a system over the next week. Wind shear is not forecasted to be ideally favourable for development, which gives it a low chance of occurring but it will be monitored for signs of development.

Development may not occur along ex-Ida since models show a blocking pattern developing across the Atlantic over the next week or two, which may form the focal point for cut-off frontal systems.

The second system of interest is one of the last tropical waves of the year near 40W south of 18N moving off towards the west near 12 mph. Visible imagery showed the inverted-V pattern very well with shower activity within 5 degrees east of the axis due to 40 knots of vertical shear. No development expected since shear will remain at these levels for the next week and two.

Any development in the Atlantic during the last 2 weeks appears will be subtropical development since westerlies have taken over the deep tropics.

Tropical Cyclone Anja

As expected in El Nino years, the Southwest Indian Ocean is off to an early start, with the first named storm and cyclone (hurricane status). Tropical Cyclone Anja is churning near 13.3S-70.0E, well east of Madagascar and the Reniuon Islands. Maximum sustain winds according to Meteo France is 100 mph with a central pressure of 950 hpa which makes it a category 2 hurricane on the Saffir-Simpson hurricane scale. However, this is a 10-minute average, as the Joint Typhoon Warning Center (JTWC) estimate winds to be near 130 mph (1-minute sustain), a category 4 hurricane. I suspect Anja to intensify some more today due to the excellent large-scale outflow pattern seen on water vapour imagery and sufficiently warm waters. The cyclone should begin to recurve into the mid-latitudes through day 4 as a trough advances from the South Atlantic.


Figure 1. METEOSAT-7 visible/infrared image of Tropical Cyclone Anja with the island of Madagascar to the left.

Ida’s deluge

Tropical storm Ida came ashore early on 10 November 2009, quickly weakened to a tropical depression and became extratropical. A strong pressure gradient then developed between the remnants of IDA and an area of high pressure that had moved over New England. This resulted in strong winds blowing toward east coast shorelines and resulted in coastal flooding. Flooding tides in Virginia were near the values set by hurricane Isabel in 2003. The remnants of IDA also dropped heavy rainfall from the Gulf Coast to New Jersey causing flash floods. The rainfall analysis below used merged rainfall Data (3B42) from TRMM, other NASA satellites, Department of Defense satellites, National Oceanic and Atmospheric Administration polar-orbit satellites, and geostationary satellites. The analysis shows IDA's remnants caused large areas of very heavy rainfall with maximums in Alabama, North Carolina and Virginia. The analysis shows a maximum value over land of over 240 mm (~9.4 inches). – NASA TRMM.


Figure 2. Rainfall accumulation through 6-13 November measured by NASA's TRMM satellite.

Water on the moon

Earlier this year, NASA scientists launched a rocket whose mission was to crash into the South Pole of the moon and help settle the theory of water on the moon. On Friday, the results of this mission were confirmed and the measurements in the explosion revealed a large amount of water lay frozen on the lunar surface. The lunar crash kicked up 25 gallons of water and that is only what scientists could see from plumes of the impact. This is one of the biggest discoveries ever made in the area of space and science and opens the moon to new exploration. I suspect this is the basis of future lunar missions and when we do finally set up base on the lunar surface, I am sure the history books will refer to this date. I have always wondered to myself, whom this water belongs to? You can just picture the lunar wars several hundred years from today. I think my ex-girl friend is sorry that she told me “go to the moon and bring back water for me.”

Weather456

Hurricane Ida bears down on the Yucatan/Western Tip of Cuba

By: Weather456, 12:26 PM GMT on November 08, 2009

Before I get into my update, I must apologize for not having an update on Saturday; I was not feeling too well.

As of 7am EDT, Ida was located near 20.8N, 85.7W or about 70 miles east-northeast of Cozumel, Mexico moving off towards northwest near 12 mph with a minimum central pressure of 983 millibars. Ida is a strong category 1 hurricane on the Saffir-Simpson Hurricane Scale and further intensification is possible. Satellite imagery along with radar imagery continued to show Ida has steadily strengthen through the evening hours with an eye evident on radar imagery. Buoy 42056 reported an incredible 65 knot wind gust as Ida pass close it early this morning. Ida has defied intensity forecasts largely because Ida modified its upper environment. Southwesterly winds ahead of a shortwave over Mexico did little to slow down Ida. Another reason was, Ida traversed some of the deepest and warmest waters in the entire Atlantic, waters that have not been touched at all this year. It is likely that if Ida was under perfect conditions, she would have easily became a category 5 hurricane. The upper environment is still conducive for some modest strengthening and since Ida has one more patch of high ocean heat content to cross before entering the Gulf of Mexico, I suspect Ida may become a category 2 hurricane. Ida will likely taper off in intensity over the Gulf of Mexico due to the combinations of an increasing baroclinic environment (shear and fronts) and cooler (not cold) sea surface temperatures. She is expected to remain a hurricane up to extratropical transition in 3-4 days.


Figure 1. Cancun, Mexico 480 KM range basic reflectivity radar showing Ida as it approached the region with a eye feature clearly evident.

Now Ida has turned northwestward after a brief trek towards the north yesterday. Ida is being steered by a deep layer ridge to its east and northeast, the same ridge that is bringing gusty winds the east coast of Florida and the Florida Keys. Ida has also sped up from an average speed of 6 mph to an average speed of 12 mph as the westerlies begin to pick up in the Gulf of Mexico. This means, Ida has a shot of reaching close to the Northern Gulf Coast before turning east. I suspect Ida will continue on this northwest to north-northwest motion through 3 days and then turn towards the north and east as a trough amplifies over the Southern United States. The exact timing of both features will determine how quickly she turns but I will go with the NHC scenario for the time being.

The storm is heading towards the Yucatan Peninsula/Western tip of Cuba in the near term and the latest wind field forecast shows Ida becoming a category 2 hurricane as it nears the resort areas. However, it seems Ida is such a small hurricane that the core of strongest winds will remain offshore; that still all can change if any jogs occur. Strong gusty winds, high seas of 25 ft and water rises of 1-2 m are expected across the region. Damage is likely to occur especially along the coastal beaches.


Figure 2. 9-hr lead projected wind-field of Ida during its closest approach to the Yucatan Peninsula along the NHC forecasted track.

For the Gulf Coast, similar effects, even through Ida will be weaker (hard to believe!). Ida will intensify a pressure gradient between it and the high pressure to its northeast. Ida and the Bay of Campeche system may again amplify the pressure gradient. Gale force winds with 20 ft seas and a long moisture fetch will be found right of Ida which will impact the Gulf Coast, preferably, the Florida Panhandle, Alabama, Mississippi and Louisiana. Expect high wind, wave, rain and possible beach erosion my mid week. There have been coastal flood and high seas advisories issued for the Northern Gulf Coast.

Weather456

Ida to emerge later today

By: Weather456, 2:05 PM GMT on November 06, 2009

Tropical Depression Ida as of 8am AST this morning was located near 14.6N-84.2W or about 50 miles away from the Gulf of Honduras, moving off towards the north near 7 mph with maximum sustain winds near 35 mph and a minimum central pressure of 1005 millibars. Satellite imagery revealed Ida has defied the NHC forecast by at least by 1 day with the center moving just north of the Nicaraguan/Honduras border with the very define low level circulation remaining well intact. This is due to the terrain-type that Ida is moving through – warm humid swamps known as the Mosquito Coast. Ida is expected to emerge over the very warm waters of the Gulf of Honduras later this afternoon at which point, due to some existing shear, modest strengthening could occur and Ida could regain tropical storm status by Saturday. It is already beginning to show signs, by looking at the convection north of Ida, that the storm will have little trouble regaining tropical storm status and there is a modest chance that rapid intensification could occur over the next 4 days while Ida is moving slowly over the Northwest Caribbean. Intensity in the Gulf of Mexico continues to be a problematic forecast.

I expect Ida to be propelled towards the north over the next 3-4 days between a ridge in the Central Caribbean and a shortwave over Southeastern Mexico. Ida may deviate towards the NNW at times due to high pressure over the Southern United States that is expected to shift east over the next week. As the high is pushed out over the Western Atlantic, a combination of the short wave, a long wave and a developing gale system will help turn Ida more towards the northeast with time and this is between 5-7 days as Ida moves through the Central Gulf of Mexico. There is also the chance that the gale system absorbed Ida, making for a mess along the Eastern Gulf Coast, especially Florida, next week.

Meanwhile, rainfall estimates indicate Ida has dumped up to 7 inches across Nicaragua over the past 3 days. About 80% of homes were destroyed in nearby Karawala, a fishing village of about 100 shacks, Nicaraguan officials said. No deaths or injuries have been reported.


Figure 1. Rainfall accumulations using passive microwave imagery and blended IR over the past 3 days.

Weather456

Hurricane Ida lashes Nicaragua

By: Weather456, 12:50 PM GMT on November 05, 2009

The 2009 Hurricane Season no longer shares the record for the least amount of hurricanes – 2 with 1982. Ida underwent rapid strengthening (not the same as rapid deepening or intensification) over the past 24 hrs and the last time we spoke, she was just an invest.


Figure 1. GOES 12 Visible/Infrared image of Hurricane Ida from this morning. Credit: NASA

Hurricane Ida is located near 12.8N-83.4W or about 60 miles north-northeast of Bluefields, Nicaragua moving off towards the northwest at 7 mph. Maximum sustain winds are near 75 mph and the minimum central pressure has dropped to 987 millibars. The latest infrared and visible images showed Ida is moving slowly towards the north-northwest and though the eye is somewhat evident, the cloud tops are not as cold as 6 hrs ago, probably due to long exposure to land. Ida has yet to make landfall but I think she has reached her maximum point since any jog to the left could send her inland and cease intensification.

Ida is expected to make landfall sometime today over Nicaragua and move slowly over the landmass of Central America for the next day, emerging over the Gulf of Honduras Saturday morning. Ida will most likely be downgraded to a depression but dissipation is becoming more unlikely since the angle she is coming is higher than expected from the first advisory. In the long-range, the models become increasingly divergent as the storm enters the Gulf of Mexico, but before it does so, it has to cross the very warm waters of the Northwest Caribbean. Shear is already beginning to show signs of retreating north, so according to how battered the storm is after emerging, Ida could undergo rapid intensification over the Northwest Caribbean. The NHC thinks Ida would be weak enough to continue northwest or north-northwest but if for some reason she explodes, then the track may shift to the right placing the Caymans and Cuba in the spotlight. For now Belize and the Yucatan remains in the cone of uncertainty. Intensity becomes problematic in the Gulf of Mexico but it seems the models agree that Ida will make it to the central northern Gulf coast, late next week.

Ida is spinning offshore dumping heavy rains and bringing tropical storm forced winds across Nicaragua and Southeastern Honduras as Mitch did in 1998. Over the next 24 hrs, Ida could dump up to 8 inches of rain over the region and that is an understatement. Using NASA’s TRMM measurements based on terrain and rainfall, there is a moderate to severe chance of flooding and landslides in Nicaragua.

The storm has already uprooted trees, knocked down power lines and forced the evacuation of 300 people on Nicaragua's Corn Island.


Figure 2. 24 hr eTRaP rainfall forecast for Ida ending 0000 UTC 6 November 2009.

This is the first time the name Ida has been use and it replaced Isabel from 2003.

Weather456

Tropical Invest 97L nears depression status

By: Weather456, 12:37 PM GMT on November 04, 2009

The area of disturbed weather located in the Southwest Caribbean continues organize this morning and is almost near depression status. Satellite imagery showed clusters of deep convection organizing nicely around a well-define low-level circulation as noted on the QuikSCAT pass from last night. The first visible images confirm a closed low-level circulation and I suspect this feature is already a depression but we will have to see what the hurricane hunters find later this afternoon. Environmental conditions appear conducive for continued development of this feature and we could have Ida by Thursday. Long-term speaking, the intensity of 97L is problematic as we have moderators such as wind shear, proximity to land and upwelling in play; as oppose to an upper anticyclone and very warm waters in the Northwest Caribbean. I suspect shear will decrease slowly and the system should not move too much near the landmass of Central America. Given these parameters, I will go above the intensity guidance and expect a strong a tropical storm in the next week.

Where will 97L go? That question is answered by how strong it will get. A weaker system favours a more west of north motion around a shallow-mid level high that will build over or offshore the Eastern United States. Some of the models show the system actually heading back west due to some type of weakening occurring as the system nears the Gulf of Mexico. A deeper system will be steered by the typical November pattern – east of north or due north. Because track is affected by intensity and intensity forecasts are difficult to predict I will go down the center of a NNW to N at times motion, finding a balance if you know what I mean. The main areas that should watch this system in the near-term are Central America – Nicaragua, Honduras and Belize - Mexico, the Caymans, Jamaica and Cuba as the system has the capability of being a rainmaker. It is still too early give a call on the United States but folks along the Gulf Coast from Florida to Texas should be prepared for any surprises. If you use my track, Florida would be the target.


Figure 1. Visible images of Tropical Invest 97L as it nears depression status.

Weather456

Watching the SW Caribbean; Invest 96L revived

By: Weather456, 12:17 PM GMT on November 03, 2009

Good day to all. This morning I am watching two systems that have potential to become named systems if conditions allow. First, a stationary area of low-pressure is located over the Southwest Caribbean producing somewhat organize clusters of convection over the extreme southern Caribbean and Central America. This morning satellite imagery showed modest improvements in the organization of the disturbance with clearly cyclonic turning just north of Panama. This is supported by last night’s QuikSCAT pass; 850 and 950 mb vorticity; and surface observations. I suspect that under continued favourable upper winds and 29C waters, that some slow development may take place over the upcoming week.

Now the real problem with development is proximity to land and an area of high shear towards the north. The models are thinking the system will not move much over the next 3 days due to weak steering flow but begins to slowly move towards north through day 4-5 as a trough swings across the area towards the north. Preceding the trough is an upper ridge, which will establish itself across the Western Caribbean providing a much more favourable upper environment over the area for further development. It is difficult to say what the system will do in the long-term but most models show the storm entering the Gulf of Mexico in about 7 days either from the Yucatan Channel or Yucatan Peninsula and instead of moving east of north like typical November systems, the system may continue west of north around the return flow of a deep layer ridge position offshore the East Coast. Meanwhile, a frontal trough is over the Central CONUS, so both features act to bring the system to the Northern Gulf coast. Still, it is too early to put any confidence in this. In the meantime, the feature will continue to dump heavy rains across southern Central America and possibly the Caymans and areas further north along Central America later this week.


Figure 1. Visible image of the area of disturbed weather located in the Southwest Caribbean Sea. This system has the potential to be designated Tropical Invest 97L.

The second system is INVEST 96L, which was never deactivated, and satellite presentations of the system improved significantly over the past 24 hrs. The system resembles a sheared tropical storm and because the feature is warm-core and detached from all frontal boundaries, any increase in shower activity near the center could result in classicisation. QuikSCAT showed an asymmetric wind field with the highest winds under the clusters of deep convection east of the center. The system will be monitored until it becomes absorbed into a frontal boundary during the next day or two.


Figure 2. Visible image of Tropical Invest 96L which resembled a sheared tropical storm. Dvorák T numbers using the shear pattern would of given this system between 2.0 and 2.5, or a minimal tropical storm. The system is warm-core and non-frontal so up for some debate.

Weather456

Subtropical Invest 96L less organize; Possible Bay of Campeche development next week

By: Weather456, 11:36 AM GMT on November 02, 2009

Satellite imagery this morning showed that the non-tropical low dubbed 96L has encountered northerly shear, which has removed the thunderstorm activity from the low-level center. It is rather a shame to see this happen after the system came very close to becoming Subtropical Storm Ida. As mentioned in the previous blog entries, time was a limited factor for this system as there are signs of the approaching frontal trough that is expected to absorb 96L over the next day or two. The invest was never really a threat to land. I will present an overview of the formation and meteorology, which made 96L partly subtropical in a later blog.

Meanwhile, models are hinting some type of development in the Bay of Campeche that moves from the Yucatan Channel next Sunday and moves north or northwestward into either Texas or Louisiana. Conditions will be marginally favourable for development and the models think it will be tropical (even though with the amount of shear it appears extra-tropical) so it will be monitored.

Weather456

Non-tropical low better organize

By: Weather456, 12:11 PM GMT on November 01, 2009

A non-tropical area of low pressure located over Central North Atlantic located about 850 miles east-southeast of Bermuda is showing some signs of organization as it continues to occlude from the westerlies. Satellite imagery and surface observations revealed the associated cold front has detached from the system and AMSU temperature brightness indicated that the cold air has fully secluded from the westerlies hence the fact why the Tropical Prediction Center has analyzed the feature as an occluded cyclone. QuikSCAT indicated that the system is generating 50 knots of winds near the center of circulation and DMSP wind speed showed the wind field has some tropical characteristics. If the feature can continue to generate convection near the center then it stands a fair chance of becoming a subtropical storm. Sea surface temperatures are near 25-26C well above ST requirements and shear over the gale center is 10-15 knots with higher shear surrounding the feature associated with the upper low the feature is embedded in – typical of these systems. I will continue to monitor the feature as it heads northwestward over the next day or two, recurving towards the north-northwest east and north of Bermuda. There is a narrow time frame of about 3 days before becoming absorbed by the next cold front.


Figure 1. Rainbow color image of the non-tropical low pressure.

Weather456


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Weather456's Tropical Weather Blog

About Weather456

With a Bachelors Degree in Environmental Sciences (2009), began tracking tropical storms in 2002 and is now a private forecaster.