TropicalAnalystwx13's WunderBlog

Short update: An early start to the 2011 Atlantic hurricane season possible

By: TropicalAnalystwx13, 8:40 PM GMT on May 27, 2011

We are now less than one week away from hurricane season, and many models are now coming into conjunction that we will be watching at least an Invest or disturbance for development by June 1. The GFS, ECMWF, NOGAPS, and other models are hinting at possible development in the western and southwestern Caribbean as pressures lower thanks to very strong ridging over the United States and an upper low moving into the Gulf of Mexico allowing for ventilation of the Caribbean with lowering pressures. What this upper low will do is not only lower pressures in the area, but it will reduce wind shear levels down to at least a moderately conducive status, something it hasn't been at so far this year because of the subtropical jet. Sea surface temperatures in the western/southwestern Caribbean run around a degree above normal (29 °C), which is definitely warm enough to support tropical mischief. One thing that may impend development some is the fact that formation of a system would be monsoonal in nature, meaning it could take a while to truly get organized, much like Hurricane Alex of last year, or TS Nicole of last year.


Figure 1. Current Sea Surface temperatures on 5/27/11.

I'll be monitoring this area very closely beginning next Monday since I plan on being gone over the weekend. At this time, I do believe we are likely to see Tropical Depression #1 or Tropical Storm Arlene by the end of next weekend. Stay tuned.

TropicalAnalystwx13

Tropical Cyclones of 2011 Tropical Weather

Updated: 12:02 AM GMT on May 15, 2012

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92L develops in the Atlantic, 90E in the Pacific; Massive EF4 devastates Joplin

By: TropicalAnalystwx13, 10:09 PM GMT on May 23, 2011

An area of disturbed weather (92L) out in the open waters of the Atlantic Ocean, several hundred miles east southeast of the Outer Banks of North Carolina, has the potential to develop into a tropical, or subtropical, cyclone over the next few days as it moves southeast at 10 - 15 mph. A very distinctive spin can be seen on satellite imagery, but according to ASCAT, its surface low is elongated at the time. Buoys in the general location of 92L indicate high barometric pressures over 1009 mb. Water Vapor satellite loops reveals that a rather large area of dry air surrounds 92L, which may keep development at a relatively slow pace. The National Hurricane Center has noted this area with a 20% yellow circle, stating that shower and thunderstorm activity remain disorganized due to strong upper-level winds. However, they do point out that tropical or subtropical development is possible within the next 48 hours.


Figure 1. Infrared imagery of 92L out in the open waters of the Atlantic.

Forecast for 92L
It does not appear that Invest 92L will impact any sort of landmass at this time. The latest SHIPS model depicts slow intensification into a tropical storm by the middle of the week, before a slow decline in intensity thereafter. Upper-level wind shear is expected to stay unfavorable for development during this time, even though lower-level shear is low to moderate (10 - 15 knots). At this point, my current forecast calls for a east southeast movement over the next couple of days, with a moderate chance, 30%, of development into a tropical/subtropical depression by Wednesday afternoon.

90E develops in the Eastern Pacific
In the Pacific, another invest (90E) has developed, with maximum sustained winds of 25 mph. The National Hurricane Center has also noted this area with a 20% yellow circle, with little movement expected over the next few days. An earlier ASCAT pass reveals that its circulation is pretty well-defined, although potentially a little elongated. Water vapor satellite loops reveal that an area of dry air lies to the north of 90E, although the invest itself has a plentiful moisture supply. My forecast for 90E calls for the system to move very little over the coming days, with slow, gradual intensification. I currently give this system a low chance, 20%, of development into a tropical cyclone over the next 48 hours.


Figure 2. Infrared imagery of 90E in the Eastern Pacific waters.

Preliminary EF-4 tornado hits Joplin, Missouri
The already historic tornado season of 2011 scored another victory yesterday afternoon/evening, when a very large and damaging tornado struck the populated city of Joplin, Missouri. At least 116 people have been killed from the tornado, and the death toll is still expected to rise. Portions of the city have been totally obliterated, and the tornado was so strong that there have been reports of pavement being ripped right out of the ground, a sign that this tornado was either a strong EF-4 tornado, which is the preliminary guess, or a weak EF-5 tornado. We will not know for sure until tomorrow, when the final decision is made. This tornado was so extreme that it will likely surpass the Tuscaloosa/Birmingham tornado as costliest on record. The Joplin, MO tornado is now the single deadliest tornado in US history, beating the previous record of 94 people in the Worcester, Massachusetts tornado (1953). This years death toll now stands at 482, making it the deadliest year for tornadoes since 1953, when 519 people died. The deadliest year in USA history was in 1925, with 794 deaths, which is also the year of the Tri-State tornado, which killed 695 people in three states.


Figure 3. An image of the Joplin, MO tornado.

Another significant outbreak expected tomorrow

The Storm Prediction Center in Norman, OK has highlighted tomorrow with a moderate risk for severe weather, stating that another tornadic outbreak is possible across the Central and Southern Plains. The organization also states that an upgrade to a high risk for severe weather may be warranted as the situation becomes more certain. The tornado threat may be as high, or even higher, than yesterdays tornado outbreak, with a good chance for large hail and damaging straight-line winds. Joplin, MO may be under the gun for severe weather tomorrow, although the highest threat will be to the southwest.


Figure 4. NOAA's Storm Prediction Center convective outlook for tomorrow, Tuesday May 24, 2011.

TropicalAnalystwx13

Tropical Cyclones of 2011 Tropical Weather

Updated: 12:03 AM GMT on May 15, 2012

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Atlantic/East Pacific Tropical Weather Outlook - 4:30 pm EST

By: TropicalAnalystwx13, 8:34 PM GMT on May 16, 2011

Atlantic Satellite Imagery


Figure 1. Rainbow imagery of the western Atlantic.


Figure 2. Rainbow imagery of the central Atlantic.


Figure 3. Rainbow imagery of the eastern Atlantic.

Atlantic Tropical Weather Discussion
All is quiet in the Atlantic basin today, and should stay that way through the next week or so before things get interested. Several models are depicting the possibility of a tropical cyclone to form in the western/southwestern Caribbean Sea by the end of next week into Memorial Day weekend. This would be caused by the strong upward pulse of MJO that is currently in the eastern Pacific moving into the Atlantic, plus the building of a ridge across the CONUS as a strong trough moves out around the 23rd. Mean upper-air forecast models depict the lowering of atmospheric pressure in the area aforementioned between the 24th - 1st time frame, which in my opinion, will be when we have our first named storm of the season - Arlene. We will have to keep a watchful eye on this as time progresses. It is way too far in advance to say this confidently, but if something were to develop, I would guess it would move northwestward and enter the Gulf of Mexico.

Meanwhile, our first tropical wave of the year was analyzed yesterday by the National Hurricane Center. Its current location puts it around 40-50W, 3-7N, locked in the ITCZ (Inter-tropical Convergence zone).


Figure 4. Infrared Imagery of our first Tropical wave of the season.

Eastern Pacific Satellite Imagery


Figure 5. Rainbow imagery of the eastern Pacific.


Figure 6. Rainbow imagery of eastern east Pacific.

Eastern Pacific Tropical Weather Discussion
There are no active storms in the eastern Pacific, or the Pacific as a whole, at this time, but just like the Atlantic basin, development may be imminent. A strong upward pulse of MJO currently lies over the eastern Pacific, which can clearly be depicted as the large swath of moisture streaming across the basin. Within this area, development is not likely, but could still occur. It would likely take several days for something to develop, due to the same problem that Hurricane Alex (2010) ultimately had - very broad area of moisture/low pressure, very hard to consolidate. The most likely time frame for development would be the 21st - 26th of this month. If a named storm were to form, it would be called Adrian.

Remember, the East Pacific hurricane season is now underway. It runs from May 15 - November 30.

TropicalAnalystwx13

Tropical Cyclones of 2011 Tropical Weather

Updated: 12:31 AM GMT on May 15, 2012

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About TropicalAnalystwx13

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