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
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 — Blog Index
Well, your latest forcast was for 6 named storms this year. So if Grace forms...
And, IIRC, last week you had us all looking at a possible storm in the GOM. Oh, wait, that was stormno, not stormt.
BTW, Sarah, if you'll stick around a bit, you'll see another name change from our old friend stormt. He has to, because of the ignore feature.
Another record breaker, coming thick and fast over the last few years.
he's the husband of Wilma, rapid intensification was expected.
But two majors for 2009 is impressive for a quiet yr
i doubt stormno cares at all about his "credibility". he only cares about getting a rise out of people and predicting gloom and destruction for the GOM.
Wow its predicting two on them in the GOM
You are correct...he was.
No one's perfect with this. And never, ever will be.
Enough of the arguing on here!
That's true.
But as the discussion makes clear, in large part, that's because we're getting vastly better at identifying, tracking, and analyzing these storms. The more sophisticated our tools, the better the chance of locating particularly intense winds within a mass of convection, or spotting a storm that never touches land.
Think of it this way. If Katrina had hit the mainland anytime before, say, 1965, we would've classed it as a Cat 3, at most, based on the observational data. Possibly a little higher anytime after mid-century if a hunter had successfully penetrated the core, but because the missions were both shorter and less frequent, there's no telling whether it would have recorded Katrina anywhere near its peak intensity. Today, though, we have detailed imagery of a storm taken with 30 minutes of its absolute, lifetime peak, no matter where it is. If it approaches land, we monitor it observationally almost continually. So inevitably, we record systems that eclipse all records.
What does my grill have to do with Tropical Cyclone formation. My backyard burner runs on propane, but my neighbor uses charcoal. Does this increase or decrease the chances of a cyclone forming??
(Just a little humor)
I would be shocked if that happens.
Look for an increase in moisture all along the northern GOM by the end of the week. Beyond that, stay tuned....
THE BASIN AND FRED IS ONLY THE THIRD MAJOR HURRICANE NOTED EAST OF
35W IN THE TROPICAL ATLANTIC OCEAN...AND THE STRONGEST HURRICANE SO
FAR SOUTH AND EAST IN OUR DATA RECORD. THIS TYPE OF SYSTEM...
HOWEVER...WOULD HAVE BEEN VERY DIFFICULT TO ACCURATELY OBSERVE
BEFORE SATELLITE PICTURES BEGAN IN THE 1960S. "
Makes you think really. How powerful were some of those storms in the 1950s? Or indeed any decade before? Some may have been weaker than imagined, but some may be even stronger. They thought Hurricane Dog was a 185mph beast. Imagine what s/he really was...
I know, I know, but sometimes on a slow day it's fun to throw reality at the trolls and see if it sticks.
Keeping fingers crossed for a continued quite GOM.
Yup! Now if that trend continues, God help anyone who's in the way of Hurricane Bam-Bam. Seriously.
Yep, my last update was for 1925. Dr. Chris Landsea is a very nice guy, always answers my mail and takes the time to exchange ideas. He is also a very good friend of Dr. Masters.. they flew together on HH missions. A very good book about the '28 cane is Black Cloud by Eliot Kleinberg. Some first person accounts that will make your hair stand on end.
It's not the opinion, sarah, it's the blanket statement of opinion without any evidence cited to back it up...
"The season is over"
"My left little toe curled under; the GOM will have a storm this weekend"
"This one will be a CAT5 and hit NOLA"
The issue is that people respond these posts at all, when that is what these individuals want in the first place. I'm as guilty as the next guy of getting my "panties in a bunch", but after years of watching these people try to disrupt the blog, every once in a while you just go off...
I apologize, for my part, but people like stormt (who, by the way, has used 15 or 20 handles to circumvent permanent bans) state the same
"opinions" over and over again, regardless of the conditions...it simply wears on the nerves
Nice convention,
fantastic convention.
Watch out Nola.
Partly correct. Systems are either in general larger and stronger than in the past, or they are striking the conus more frequently. Either way, storm surge, wind, and wind field records were beat with Rita and Ike respecitive in the NW Gulf (or better yet just ask any insurance adjuster near the Gulf Coast). Only in the past few years, and it has no bearance on past storms were not not taken note of in this area. They were just not as strong, not breaking as many records.
Kudos, Cotillion, you are probably right. Thanks.
Remember, storm names come from local cultures, so that'd be Typhoon Bam-Bam - an Indonesian name. And since Typhoons can be the fiercest Tropical Cyclones of all, I gotta say, Whoa Wilma!
I’ve corresponded with Eliot several times, and of course, read Black Cloud. I was even recommending it myself on here a few weeks ago. If there’s one thing that man knows, it’s Florida history…
Not a quiet year at all, really, unless the basin completely shuts down.
6,2,2 halfway through. 12,4,4 would be the climatology. Slightly above average year. Average is 10.1, 5.9, 2.5.
Bill
Fred
Kate
Larry
Hmm, it's an interesting debate, really. I think at times when it comes to storms we may actually underestimate our "predecessors" if you will, in storm estimation. They did have some reports come in, and after the war, radar was also available for those close to land. Given that Katrina was straddling the loop current, I'm fairly sure they would of recorded her as a 170mph-ish storm. If she was out in the middle of Atlantic, then of course, much more difficult to ascertain certainties.
In this, I specifically mean wind speeds; pressure at the time is far too difficult to determine and even to this day there may be cases where the actual pressure isn't recorded or calibrated. If memory serves, then there were still some hours that Wilma was over warm waters after the last HH run which gave them a 881mb reading (that was later calibrated to 882mb). Who knows, could well of been a sub-880.
If history is correct (and it is more often than we like to admit), then we've not hit the AMO peak yet. That's the end of the next decade if the estimations are right. With more heat potential available, plus the other heat on top, we could possibly even see the unfortunate event of Wilma's record broken.
Gilbert did hit 888mb and that was in La Nina/Negative AMO.
umm, consider the source....
The source is nature.
Have you seen the beautifull convention?
LOL,Flood I thought it sounded like the title for an old B movie from the 60's
Viewing: 101 - 151
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 — Blog Index