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
Reader Comments
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There's only an X......
that's not true, Koritheman, myself and others were going slightly above the NHC intensity guidance and expected Fred to become a hurricane, thats why its not much of a surprise since it was expected. Also when he became a hurricane, many pointed out he would rapidly intensify as conditions allowed it.
However, ur right, intense hurricanes do create their own steering pattern and environment but that does not mean they will create a "westward track of their own". Just as how they can affect their own steering flow, they can also be affected by external patterns.
LOL, it does has that "tourist lobster-red" look to it, doesn't it??? lol Lots of moisture and heavy downpours in this general area today....
Quintessence of Meteorological wisdom.
For this second week of September, we continue to travel the coastline destroyed by Hurricane Katrina’s record storm surge. This is something that has never been shown on the news or talked about, either in the overall, or in detail. What you’ll be seeing here is what people on the Gulf Coast have been calling the “Invisible Coastline” for almost a year now.
Today we look the section of eastern Jackson County, that contains the main communities of Pascagoula, Moss Point, and Escatawpa, as well as a number of smaller ones.
From Google Maps, the location of this area along the Gulf of Mexico coastline impacted by Katrina:
both are there.
Shear wasnt to increase until almost 120 hrs after TD 7 1st advisory.
Heavy Rains Likely....
Low pressure will likely develop over the Gulf to our south and southwest by Friday. This low will likely move slowly to the north with plenty of tropical moisture working northward into our area. There will be the potential for rainfall totals in excess of 5 inches by Saturday afternoon. The low will also be closely watched for any tropical development. With plenty of clouds, temperatures will be cooler than normal for afternoon highs.
I got a couple of math problems that I could use some help on if someone wants to take a crack at them, let me know, would love to do it on my own, but ive had a long day :P (but im sure many of you have had longer)
SSt
What does that mean? lol
"Low pressure over deep South Texas is causing a large area of clouds, showers and thunderstorms over parts of southern and southeastern Texas. There is no threat for tropical development in the short term as long as the lowest pressure stays over land. However, if this low pressure re-develops along or off the Texas coast and if shearing wind flow over this system diminishes, there might be some opportunity for tropical development. Computer forecasts are hinting at this possibility later Friday into Saturday.
By AccuWeather.com Expert Senior Meteorologist Dan Kottlowski"
Tropical Cyclone Heat Potential Loop
Depth 26.C Isotherm
Tropical Cyclone Heat Potential
Methodology
Sea surface temperature (SST) provides a measure of the surface ocean conditions, however no information about the subsurface ocean thermal structure (approximately the upper 50 m of the ocean) can be derived from SST alone. For instance, it is known that the oceanic skin temperature erodes when the sea surface is affected by strong winds, creating a well-mixed layer that can reach depths of several tens of meters. Moreover, warm ocean features, mainly anticyclonic rings and eddies, are characterized by a deepening of the isotherms towards their centers with a markedly different temperature and salinity structure than the surrounding waters. Several studies have shown that observations of sea surface height (SSH) are strongly correlated with the thermal structure of the upper ocean (e.g. Goni et al. 1996; Gilson et al. 1998; Mayer et al. 2001; Willis et al. 2004). Based in this virtually ubiquitous relationship, we developed a methodology to estimate fields of isotherm depth from the SHA fields derived from satellite observations.
The tropical cyclone heat potential (hereafter TCHP), is defined as a measure of the integrated vertical temperature from the sea surface to the depth of the 26°C isotherm. This parameter is computed globally from the altimeter-derived vertical temperature profiles estimates in the upper ocean (Shay et al., 2000). Different methods have been developed to calculate this vertical thermal structure of the upper ocean. Up to three different procedures have been developed at NOAA/AOML for this purpose. In chronological order, the first TCHP fields were obtained using a reduced-gravity model (Version 1.0). In May 2005, a second algorithm based on linear regression analysis (Version 2.0) was implemented and all the fields available through this website were updated accordingly. Finally, in October 2008, a third approach was put into service, in order to provide better agreement with observations and remove outliers mainly affecting the Gulf of Mexico and Central Pacific regions (Version 2.1).
For the GFS the ensembles are the model run with different initial conditions at a lower horizontal resolution.
ENSEMBLE FORECASTING AT NCEP
The current GFS is run at a resolution of ~35km for the first 180 hours, ~70km 180-364 hours. The ensembles are run at a resolution of ~100km.
fred has a girl chasing him
alright, I pm'ed you lol
CSI - 06
Location:Chevron Platform, ST-52B, South of Terrebonne Bay, Louisiana, Coordinates:-90º29',28º52'
ADCP Directional Spectrum
ok who quoted him?
I agree xD
Conditions at 42002 as of
(5:50 pm CDT)
2250 GMT on 09/09/2009:
Unit of Measure: Time Zone:
Click on the graph icon in the table below to see a time series plot of the last five days of that observation.
5-day plot - Wind Speed Wind Speed (WSPD): 9.7 kts
5-day plot - Wind Gust Wind Gust (GST): 17.5 kts
5-day plot - Wave Height Wave Height (WVHT): 2.0 ft
5-day plot - Dominant Wave Period Dominant Wave Period (DPD): 3 sec
5-day plot - Average Period Average Period (APD): 3.2 sec
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.88 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): -0.01 in ( Falling )
5-day plot - Air Temperature Air Temperature (ATMP): 81.5 °F
5-day plot - Water Temperature Water Temperature (WTMP): 86.4
Viewing: 951 - 1001
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