Fred rapidly intensifies; new wunderground storm surge section launched
Hurricane Fred put on an impressive burst of intensification overnight, and is now a major Category 3 hurricane with 120 mph winds. However, Fred is not a threat to any land areas for at least the next week. Satellite imagery of Fred shows the spectacular signature of a classic Cape-Verdes type major hurricane, with a prominent eye, well-developed low-level spiral bands, and high cirrus clouds denoting excellent upper-level outflow on three sides. It is quite unusual to have such a powerful system so far east in the Atlantic, and Fred is only the third major hurricane to exist east of 35W. Fred is also the strongest hurricane so far south and east in our data record. However, this type of system would have been difficult to document before satellite pictures began in the 1960s.
Figure 1. Visible satellite image of Hurricane Fred at 10:30am EDT 9/9/09. Fred was a Category 3 (120 mph winds) at this time.
The forecast for Fred
Wind shear through Thursday morning is expected to stay in the low range, 5 - 10 knots, and ocean temperatures will be about 1 - 2°C above the threshold needed for tropical cyclone formation. Given these conditions, plus such factors as the temperature at 200 mb and the amount of moisture between 700 mb and 500 mb, this morning's run of the SHIPS model computes that the Maximum Potential Intensity (MPI) Fred can reach tonight is 140 mph (121 knots), which would make it a Category 4 hurricane. This is the strongest a hurricane can get in this region of the atmosphere. Very few hurricanes ever reach their MPI, and it will be interesting to see how close Fred gets to this mark.
Shear will rise to the moderate range, 15 - 20 knots, Thursday through Friday, then increase to the high range, 20 - 40 knots, Saturday through Sunday, thanks to a strong trough of low pressure traversing the North Atlantic. This should weaken Fred to a tropical storm five days from now. The trough will also pull Fred to the northwest and then north. Most of the models foresee that this trough will not be strong enough to fully recurve Fred to the northeast and out to sea. However, another strong trough of low pressure is forecast to traverse the central Atlantic about eight days from now, and this trough should be strong enough to recurve the storm northeastward out to sea. The odds of Fred making it all the way across the Atlantic to threaten land areas appear low at this time.
Elsewhere in the tropics
A weak front is expected to move off the Texas coast Friday and linger along the coast for several days. Beginning on Friday, we will need to watch the Western Gulf of Mexico for possible development of a tropical cyclone along this front. Any storm that develops would likely move northeast or north-northeast and impact Louisiana and northern Texas coast. The models are less enthusiastic this morning about developing such a storm than they were in previous runs, and there will be some high wind shear to the west for a potential tropical system to contend with.
New wunderground storm surge section launched
The Weather Underground is pleased to announce the release of the Internet's most comprehensive hurricane storm surge web pages. The new storm surge section provides more than 500 detailed, zoomed-in storm surge maps from the official storm surge model used by the National Hurricane Center--the Sea, Lake, and Overland Surge from Hurricanes (SLOSH) model. I've created SLOSH model worst-case flood maps for Category 1, 2, 3, 4, and 5 hurricanes for the entire U.S. Atlantic coast, plus Hawaii, Puerto Rico, the Virgin Islands, and the Bahamas. Zoom-in maps of fifteen important cities such as Miami, New York City, Boston, Tampa, and Corpus Christi are included. To help coastal residents see how past storms have affected their region, the wunderground storm surge pages also include SLOSH model animations of the surge for more than 40 historic storms--from the Great Colonial Hurricane of 1635 to Hurricane Ike of 2008. You can access the new storm surge web pages.from our Tropical/Hurricane page, on the right side of the page under my blog box. I encourage all coastal residents along the U.S. coast to take the time to familiarize themselves with the storm surge risk where they live.
Figure 2. Sample water depth inundation image (left) and storm tide image (right), created using NOAA's SLOSH model. These Maximum of the "Maximum Envelope of Waters" (MOM) plots are for Tampa Bay, Florida, for a mid-strength Category 4 hurricane (sustained winds of 143 mph) hitting at high tide.
How to interpret the storm surge images
There are two sets of images available. The first set, titled "Maximum Water Depth", shows the water depth at each grid cell of the SLOSH domain. Thus, if you are inland at an elevation of ten feet above mean sea level, and the combined storm surge and tide (the "storm tide") is fifteen feet at your location, the water depth image will show five feet of inundation. The second set of images, titled "Maximum Storm Tide", shows how high above mean sea level the sum of the storm surge plus the tide reaches. Over the ocean, the storm tide and water depth images will show the same values. The storm tide images contain no information about how deep the water will be inland, and are generally less useful than the water depth images. All of these Maximum of the "Maximum Envelope of Waters" (MOM) images were generated for high tide, and thus show worst-case inundation scenarios for mid-strength hurricanes of each Saffir-Simpson Category (Category 1, 2, 3, 4, and 5). Category 5 hurricanes have never occurred in the Mid-Atlantic or New England regions, so there are no Category 5 images shown there. No single storm will be able to cause the level of flooding depicted in the SLOSH storm surge images along the entire coast. A sample set of storm surge images for a Category 4 hurricane hitting Tampa Bay is shown in Figure 2. Black lines mark the coastline, and also delineate the grid the SLOSH model used. There may be storm surge present outside the boundaries of the grid, so pay attention to where the grid boundaries are. Also, if you see a high surge modeled for a narrow waterway that goes right up to the edge of the grid boundary, don't believe it. The model puts an artificial barrier at the grid boundary, and the surge is piling up against this non-existent barrier. Empty brownish grid cells with no coloration show where no inundation is computed to occur. St. Petersburg becomes two islands in a worst-case scenario Category 4 hurricane, as shown by the brown areas surrounded by colored areas of storm tide (this did occur during the Great Gale of 1848, a Category 4 hurricane that hit the city). The tide level is marked at the bottom of the color legend, and is 1 foot in this example. The left "maximum water depth" image shows how high above each grid cell the storm tide reaches. The storm tide--the combination of the storm surge plus the 1 foot high tide--reaches as much as 27 feet above mean sea level (pink colors) near downtown Tampa (right-hand "maximum storm tide" image). The amount of inundation inland is controlled by the elevation of the land. Some of the inland regions near downtown Tampa being inundated by the 27-foot storm tide are at an elevation of 19 feet, so as much as 8 feet of inundation will occur at those locations (dark blue colors in the left-hand "maximum water depth" image). Interstate highways are the thick grey-green lines, and smaller highways are shown as dark green and light green lines. If a road is inundated by storm surge, it will not appear. County boundaries are shown in red.
Twenty years ago on this date
On September 9, 1989, satellite imagery detected a strong tropical wave with plenty of spin and heavy thunderstorm activity moving off the coast of Africa, just south of the Cape Verdes Islands. The satellite analyst at the National Hurricane Center duly noted the tropical wave, the 35th such wave to move off Africa that year, in his tropical weather discussion. No one could suspect that the routine-looking tropical wave would eventually grow to become Hurricane Hugo--the costliest Atlantic hurricane of all time.
Jeff Masters
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I totally agree with you, wish the admins would do a better job with all there trolls spoiling this blog for people that post proper info or for people that are looking for proper info, not ????-castings.
Thanks for posting it; a good reminder for this time of the year.
We are a mostly self Policing Blog...and admin gets their Bell rung if you flag the posts that need it.
Connections Among Solar Cycle, Stratosphere and Ocean Discovered
Work in sync to generate periodic global weather patterns
Posted August 31, 2009
Subtle connections among the 11-year-solar cycle, the stratosphere and the tropical Pacific Ocean work in sync to generate periodic weather patterns that affect much of the globe, according to research results appearing this week in the journal Science.
The findings will help scientists get an edge on predicting the intensity of certain climate phenomena, such as the Indian monsoon and tropical Pacific rainfall, years in advance.
"It's been long known that weather patterns are well-correlated to very small variations in total solar energy reaching our planet during 11-year solar cycles," says Jay Fein, program director in the National Science Foundation (NSF)'s Division of Atmospheric Sciences, which funded the research. "What's been an equally long mystery, however, is how they are physically connected. This remarkable study is beginning to unravel that mystery."
An international team of authors led by the National Center for Atmospheric Research (NCAR) in Boulder, Colo., used more than a century of weather observations and three powerful computer models to tackle one of the more difficult questions in meteorology: if the total energy that reaches Earth from the Sun varies by only 0.1 percent across the approximately 11-year solar cycle, how can it drive major changes in weather patterns on Earth?
The answer, according to the study, has to do with the Sun's impact on two seemingly unrelated regions.
Chemicals in the stratosphere and sea surface temperatures in the Pacific Ocean respond during solar maximum in a way that amplifies the Sun's influence on some aspects of air movement.
This can intensify winds and rainfall, change sea surface temperatures and cloud cover over certain tropical and subtropical regions, and ultimately influence global weather.
"The Sun, the stratosphere, and the oceans are connected in ways that can influence events such as winter rainfall in North America," says NCAR scientist Gerald Meehl, the lead author of the paper. "Understanding the role of the solar cycle can provide added insight as scientists work over the next decade or two toward predicting regional weather patterns."
The results builds on recent papers by Meehl and colleagues exploring the link between the peaks in the solar cycle and events on Earth that resemble aspects of La Ni%uFFFDa events, but are distinct from those larger patterns associated with changes in pressure and known as the Southern Oscillation.
The connection between peaks in solar energy and cooler water in the equatorial Pacific was first discovered by Harry Van Loon of NCAR and Colorado Research Associates, a co-author of the paper.
The contribution by Meehl and his colleagues is to document that two mechanisms that had been previously theorized in fact work together to amplify the response in the tropical Pacific.
The team first confirmed a theory that the slight increase in solar energy during the peak production of sunspots is absorbed by stratospheric ozone.
The energy warms the air in the stratosphere over the tropics where the sunlight is most intense, while also stimulating the production of additional ozone there that absorbs even more solar energy.
Since the stratosphere warms unevenly, with the most pronounced warming occurring at lower latitudes, stratospheric winds are altered and, through a chain of interconnected processes, end up strengthening tropical storms and precipitation.
At the same time, the increased sunlight at solar maximum causes a slight warming of ocean surface waters, especially across the subtropical Pacific, where Sun-blocking clouds are normally scarce.
That small amount of extra heat leads to more evaporation, producing additional water vapor. In turn, the moisture is carried by trade winds to the normally rainy areas of the western tropical Pacific, fueling heavier rains and reinforcing the effects of the stratospheric mechanism.
The top-down influence of the stratosphere and the bottom-up influence of the ocean work together to intensify this loop and strengthen the trade winds.
As more sunshine hits drier areas, these changes reinforce each other, leading to less clouds in the subtropics, allowing even more sunlight to reach the surface, and producing a positive feedback loop that further intensifies the climate response.
These stratospheric and ocean responses during solar maximum keep the eastern Pacific even cooler and drier than usual, producing conditions similar to a La Ni%uFFFDa event.
However, the cooling of about 1-2 degrees Fahrenheit is focused further east than in a typical La Ni%uFFFDa, is only about half as strong, and is associated with different wind patterns in the stratosphere.
Earth's response to the solar cycle continues over the year or two following peak sunspot activity. The La Ni%uFFFDa-like pattern triggered by the solar maximum tends to evolve into a pattern similar to El Ni%uFFFDo, as slow-moving currents replace the cool water over the eastern tropical Pacific with warmer water.
Again, the ocean response is only about half as strong as with El Ni%uFFFDo, and the lagged warmth is not as consistent as the cold event-like pattern that occurs during peaks in the solar cycle.
Solar maximum could potentially enhance a true La Ni%uFFFDa event or dampen a true El Ni%uFFFDo event. The La Ni%uFFFDa of 1988-89 occurred near the peak of solar maximum.
That La Ni%uFFFDa became unusually strong and was associated with significant changes in weather patterns, such as an unusually mild and dry winter in the southwestern United States.
The Indian monsoon, Pacific precipitation and sea surface temperatures, and other regional climate patterns are largely driven by rising and sinking air in Earth's tropics and subtropics.
The new study could help scientists use solar-cycle predictions to estimate how that circulation, and the regional climate patterns related to it, might vary over the next decade or two.
To tease out the elusive mechanisms that connect the Sun and Earth, the study team needed three computer models that provided overlapping views of the climate system.
One model, which analyzed the interactions between sea surface temperatures and lower atmosphere, produced a small cooling in the equatorial Pacific during solar maximum years.
The second model, which simulated the stratospheric ozone response mechanism, produced some increases of tropical precipitation but on a much smaller scale than the observed patterns.
The third model contained ocean-atmosphere interactions as well as the role of ozone. It showed, for the first time, that the two combined to produce a response in the tropical Pacific during peak solar years that was close to actual observations.
"With the help of increased computing power and improved models, as well as observational discoveries, we are uncovering more of how the mechanisms combine to connect solar variability to our weather and climate," Meehl says.
Very true and if people stopped quoting them i think they would go away because of lack of attention
Your Welcome. Sure is, storms can pop up anywhere in September.
Rather, its the wave that was ahead of 95L.
I have been flagging alot of posts yet they are still here, I am pretty sure the posts i flag other people flag them too.
Link
TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED SEP 09 2009
FARTHER TO THE E...AN UPPER LEVEL LOW IS CENTERED NEAR 24N68W AND IS GENERATING AN AREA OF ISOLATED SHOWERS FROM 23N-27N BETWEEN 65W-70W. E OF THIS AREA... A 1014 MB SURFACE LOW IS CENTERED NEAR 20N60W AND IS REMNANT
ENERGY FROM THE TROPICAL WAVE MOVING ACROSS THE ERN CARIBBEAN.
Fred Funktop? Sounds like some disco-obsessed 60s' DJ...
CV storms can be late in the season; Inez in 1966 made landfall in SOFL on October 6 or 7...
don't worry they will be replaced with empty space soon enough
and the tropical wave is in the Eastern Caribbean is the wave ahead of 95L.
I thought you might! I'll let you have the surfing, I'll be inshore fishing if we don't get a lot of rain or if it does rain it will be a weekend of football watching for me!
Generally the stronger the storm, the further up in the atmosphere its convective cloud tops reach. So stronger storms are steered by the upper levels as well.
No worries, man...sometimes its hard to let things slide
It involves the strength of the storm. A stronger storm will be affected by higher level steering currents
Seems to have hit the floor for the time being. 6.1 on all ratings (CI, Final T#, Adj T#, Raw T#.)
And here's a nice example of why ADT's so jumpy at times, perhaps too sensitive to fluctuations in satellite observations (And probably why, along with its problems with handling weak systems, that the NHC prefer the human-orientated observations from the TAFB/SAB, rather than the computer-orientated UW ADT.)
(If unsure, notice the scene type and the three readings given.)
2009SEP09 064500 4.0 990.4/ +3.4 / 65.0 4.0 4.2 4.3 0.7T/6hr OFF OFF -69.39 -70.33 UNIFRM N/A 12.93 31.19
2009SEP09 071500 4.0 990.4/ +3.4 / 65.0 4.0 4.2 4.2 NO LIMIT OFF OFF -58.90 -69.52 UNIFRM N/A 12.97 31.25
2009SEP09 074500 4.1 988.8/ +3.4 / 67.4 4.1 4.5 6.1 0.5T/hour OFF OFF -32.41 -69.18 EYE -99 IR 13.01 31.31
2009SEP09 081500 4.2 987.2/ +3.4 / 69.8 4.2 4.5 6.4 0.5T/hour OFF OFF -13.63 -69.80 EYE -99 IR 13.04 31.37
---
2009SEP09 101500 5.0 973.3/ +3.3 / 90.0 5.0 5.9 6.2 2.2T/6hr OFF OFF -24.10 -69.70 EYE -99 IR 13.45 31.73
2009SEP09 104500 5.0 973.2/ +3.2 / 90.0 5.0 4.3 4.3 NO LIMIT OFF OFF -44.46 -69.95 UNIFRM N/A 13.49 31.80
2009SEP09 111500 5.2 969.2/ +3.2 / 94.8 5.2 6.0 6.2 2.2T/6hr OFF OFF -21.81 -68.67 EYE -99 IR 13.53 31.97
Super Typhoon Tip in middle
Typhoon Sarah at left
Technical Attachment
AN OVERVIEW OF NHC PREDICTION MODELS
Bernard N. Meisner
Scientific Services Division
National Weather Service Southern Region
not soon enough for my liking,
good afternoon all,
as bad as these trolls have been, a lot of it is because new people frequently ask questions, and sadly, the trolls are sometimes the only people to answer them, just my two cents
if it finds a favourable upper enviroment which looks slim right now
Cheers AussieStorm
take care mate :P
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