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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I would not be surprised to see at least one of those home grown in the GOM
AOI
AOI
AOI
AOI
Tropical Update #25
recent imagery on Fred =]
Link
Takes awhile to get the latest runs.
The EURO (ECMWF) Link
I keep doing it, sorry, it was suppose to say Fred. For some I keep mixing the 2.
That model is not very good always predicts doomsday systems.
Yea...Bill was the perfect "Caster-cane". All the types casters here were all over this one. When Bill was moving NW, some say it was moving SW LOL
Looks so me also, a little north of wnw, i'm soon looking for a wnw to a N of due west to take place at least for a couple of hours, jmo.
Second interesting thing is still being able to see the Cape Verdes in all the imagery for Fred. Looks like he plans to stick close to home for the rest of his natural life....
Finally, it looks like those troughs are working in the EPac too, because Linda looks set on a NW course for now....
Really folks over the last several years this ****casting stuff has gotten so out of hand. It really takes away from what in many other aspects is a wonderful place to learn and discuss. Can't we leave the name calling to children?
and left Erika. Ma boy, all casters were out in full force for her
yep Fred still hasn't reached 15N but it should soon
also look like some shear is affecting Fred
the majority of the convection seems to be on the NE side
You would make a good diplomatic liaison. What is all the hype on the UKMET model? Got any ideas? Why do you think it is differing than the others so early?
BTW... If this ever happens, nice knowing you:
still shows TX/LA....hmmmm
Yep Hurricane Lenny
formed in the western Caribbean and tracked eastward xD
that was a crazy one lol
oh and it was in 1999
Lenny 1999 after it weakened over the Leeward Islands. Now Lenny moved ene to ne most of the time (that was unusual), but its rare for cyclones to go ESE but its happened before.
Now that's more like it Patrap!! We are leaving in a few minutes for an Italian restaurant, you just worked up my appetite! See you all later. Remember all, be nice to each other.
It continued to strengthen into a major hurricane that morning, becoming the strongest storm ever recorded so far south and east in the Atlantic basin in the satellite era, and only the third major hurricane on record east of 35W.
well that "nothing" season of 2009 Broke a record LOL. Anyways bout 11 weeks to go.
Just noticed that it's listing a high tide of 3.5 feet. Around here our high tides average 7-9 feet, so you can add another 3-6 feet to those storm tide totals. A 38 foot storm tide with 20 foot waves on top... I think even I'd pack my bags for that one.
A HURRICANE WARNING REMAINS IN EFFECT FOR DUTCH ST. MAARTEN...
FRENCH ST. MARTIN...ST.BARTHELEMEY...ANGUILLA...SABA...ST.
EUSTATIUS...ST. KITTS...NEVIS...MONTSERRAT...ANTIGUA...AND BARBUDA.
AT 2 AM AST...0600Z...THE CENTER OF HURRICANE LENNY WAS LOCATED
NEAR LATITUDE 18.0 NORTH...LONGITUDE 62.9 WEST...OR OVER THE ISLAND
OF ST. BARTHELEMEY.
LENNY HAS DRIFTED SOUTHEAST OVER THE PAST FEW HOURS.
Hey hydrus, if you are from Miami, you must get as tired as I, when all our mayors and Civil workers say,"Hope for the best and prepare for the worst" every time a storm is in our area. I cringe and just "HUNKER DOWN" every time I hear that phrase. I am in Ft. Lauderdale.
who said 2009 would be boring =P
"THURSDAY NIGHT IS WHERE THINGS START TO GET INTERESTING. THE GFS IS
MAINTAINING A SHORTWAVE OVER THE WESTERN GULF...STARTING TO ORGANIZE
A SURFACE LOW NORTH OF THE SEMI PERMANENT BAY OF CAMPECHE/MEX COAST
SURFACE LOW. NAM ON THE OTHER HAND...HAS BEGUN TO ORGANIZE TWO
SURFACE LOWS OVER THE GULF...WITH ONE EAST OF KBRO...THE OTHER OVER
THE EASTERN GULF. HAVE LEANED TOWARDS THE MAV/GFS NUMBERS...ONLY
BECAUSE FEEL THAT THE INFLUENCE THE EASTERN SYSTEM THE NAM IS
ORGANIZING IS OUT TO LUNCH. MAY BE WRONG...BUT NONE OF THE OTHER
GUIDANCE HAS THIS(THE 12Z ECMWF IN...WITH SOLUTION UP TO THIS POINT
CLOSER TO THE GFS).
FOR FRIDAY...FRIDAY NIGHT...NAM IS ADVERTISING BOTH GULF FLOWS
MEANDERING NORTH. WITH THE WESTERN LOW OFFSHORE OVER WARMER GULF
WATERS AND AWAY FROM LAND INFLUENCES...IT ORGANIZES INTO A NICE
CLOSED SYSTEM...MAYBE TROPICAL. THE GFS KEEPS THIS LOW ALONG THE
COAST...LIMITING ANY SPIN-UP...BUT DOES APPEAR TO BE ORGANIZING A
WARM FRONT OVER THE NORTHERN GULF. FOR THE FORECAST...HAVE LEANED
TOWARDS THE GFS SOLUTION...TEMPERING WITH SOME DIURNAL PRECIP
VARIATION.
.LONG TERM...(SATURDAY ON)SATURDAY INTO SATURDAY NIGHT...GFS IS
ADVERTISING A SURFACE LOW FINALLY ORGANIZING...AS THE WARM FRONT
ORGANIZING OVER THE GULF MOVES TOWARDS...THEN STALLING ALONG THE GULF
COAST. THE SURFACE LOW IS BEING ADVERTISED MOVING FROM NEAR KCRP TO
SOUTH OF KJAN OVER THE WEEKEND INTO MONDAY MORN. THIS SETS UP A GOOD
ISENTROPIC UPGLIDE SITUATION FOR THE WEEKEND...WITH A WET WEEKEND IN
THE WORKS. THE ECMWF IS PAINTING A SLIGHTLY DIFFERENT
SCENARIO...TAKING THE SYSTEM AND ITS UPPER DYNAMICS NORTHWARD OVER THE
SOUTHERN PLAINS...PROVIDING A LESS SOUPY WEEKEND. 00Z ENSEMBLES TEND
TO BEAR THIS OUT...SO FEEL THAT A LEAN TOWARDS THE ECMWF SOLUTION
OVER THE WEEKEND IS A BETTER SOLUTION.
FOR THE FIRST HALF OF THE COMING WEEK...GFS IS ADVERTISING THE SYSTEM
NEAR KJAN MEANDERING AROUND/OVER THE FA...PROVIDING AN UNSETTLED
PERIOD. ECMWF KEEPS THIS SYSTEM OVER THE PLAINS...LIMITING THE IMPACT
TOT HE FA...BUT STILL KEEPING A MOIST ONSHORE FLOW AND DAILY
AFTERNOON/EVENING TSRA FOR THE FA."
Man thank goodness we live in the period of time were SC and Georgia do not get hit as often. I remember reading that in the 1800's both states got hit more often.
Is it too late in rge season for something to spin up in the GOM? I thought that was an June or July thing?
Look at the graphics on post 197, page 4.
Thanks, just got nback from Home depot. Going to page 4 now
certainly if a storm looped, right?
Viewing: 801 - 851
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