Disturbance 98L probably no threat to land
A tropical disturbance (98L), is located midway between Africa and the Lesser Antilles Islands. This disturbance has a well-defined surface circulation, and has developed a modest amount of heavy thunderstorm activity overnight. This morning's QuikSCAT pass (Figure 1) shows a complete, circular wind pattern around the low pressure center of 98L, but top winds were only 25 mph. Wind shear is moderate, about 15 knots, and Sea Surface Temperatures are 28°C, which is about 2°C above the 26°C threshold needed to support a tropical cyclone. There is a large amount of dry air to the north and west of 98L, and this dry air is interfering with development.
The global computer models predict differing amounts of wind shear in the path of 98L as it moves west-northwest at 10 mph over the next three days. The ECMWF, GFS, and UKMET models do not develop 98L, while the NOGAPS, GFDL, and HWRF do. The models that do develop 98L predict that a strong trough of low pressure will turn 98L to the northwest and then north beginning on Monday, with the result that 98L misses the Lesser Antilles Islands by at least 500 miles. Given the moderate or higher wind shear in 98L's path, and dry air to the northwest, the system should develop only slowly. NHC is giving 98L a medium (30 - 50%) chance of developing into a tropical depression by Sunday. At this time, it does not appear that 98L will ever threaten any land areas.
The remains of Hurricane Fred are still spinning away, near 25N 66W, about 900 miles east of Florida. Wind shear is 20 knots, which is marginal for development, and there is very dry air surrounding ex-Fred on all sides. None of the computer models develop ex-Fred, and it will have a tough time regenerating with so much dry air and wind shear. The remains of Fred should move over Florida Monday night or Tuesday morning.
Figure 1. Morning QuickSCAT image of the Atlantic, showing the well-defined surface circulation of disturbance 98L. Image credit: NOAA/NESDIS.
One year anniversary of Hurricane Ike
I've been focusing this week on the 20th anniversary of Hurricane Hugo, but we also passed the one year anniversary of Hurricane Ike. Many areas along the Texas and Louisiana coast affected by Ike have fully recovered, but recovery efforts will still take many more years in other areas. In Galveston, which suffered $3.2 billion in damage, 75% of the businesses have reopened, and 95% of the population has returned. Boston.com has posted a very nice series of clickable images that show before and after scenes of some of the areas that have recovered from Hurricane Ike.
Ike washed away huge sections of beach and dunes that helped protect the Texas coast from more serious damage, and this week the state legislature approved $135 million in funds to help replace these critical natural protection systems. The restored beaches will probably last ten years, barring another strike by a hurricane of Ike's stature. Texas considers two-thirds of its 367-mile shoreline to be critically eroding, which it defines as a historical rate of more than 2 feet a year. Much of this erosion can be blamed on sea level rise. Global sea level rose seven inches over the past century, and is expected to rise at least that much over the coming century.
Figure 2. Villagers in Haiti plant one of their "Million Tree Campaign" trees. Image credit: Lambi Fund of Haiti.
Hurricane relief donations
There hasn't been a need for new hurricane-related disaster relief efforts this year, in stark contrast to 2008. However, the charities we rely on to provide disaster relief still require funds to operate in quiet years, and I encourage you to consider a donation at this time to one of my two favorite disaster relief charities. Portlight.org, which was very effective at helping out isolated, under-served communities in the wake of Hurricane Ike, is committed to raising $12,000 to purchase and outfit a mobile kitchen. This kitchen will be capable of feeding up to 2,000 people two hot meals per day in post-disaster situations. The Lambi Fund of Haiti has launched its "Million Tree Campaign", which aims to use local labor to plant a million trees over the next three years along severely deforested slopes in Haiti. Both of these charities wrote to me several times last year about the stunning generosity readers of this blog showed with their donations. Thanks!
Twenty years ago today
As Hurricane Hugo approached the U.S. Virgin Islands in the early morning hours of September 18, 1989, the storm slowed down to 10 mph. The slower speed allowed Hugo to punish the island of St. Croix with the worst beating of any location along the hurricane's destructive path. At 2am local time on September 18, 1989, Hurricane Hugo's eyewall struck St. Croix, bringing incredibly ferocious Category 4 winds, sustained at 140 mph. The hurricane's gusts were remarkably violent, and many residents witnessed tornado-like vorticies barreling across the island as the hurricane raged about them. A storm surge of 2 - 3 feet, topped by battering waves 20 - 23 feet high, assaulted the coast, adding to the destruction. Wunderground member Mike Steers wrote me to describe his experience on St. Croix: "Hugo was incredible. Many vortexes came in that night. The roar and intensity of the winds that night were incredible. When the eyewall came over, we were forced to take refuge in the bathroom as the rest of the house came apart. The pressure was so low outside the house that all of the water was sucked out of the toilet and an air draft was created through the toilet. Just when I thought it was as bad as it would get, the intensity of it all dialed up even higher. Dozens and dozens of times, my ears would violently pop due to rapid pressure changes. The next morning, of course, the devastation was unbelievable. In my front yard was a 18-foot boat with an outboard on it, that had been picked up from a marina two miles away. I had lost my house, and job, the Seaplane company I was a pilot for. After a couple months, I had to leave everything behind. In some respects, after 20 years, there an many aspects of the society that have yet to recover". Two people were killed on St. Croix, 80 injured, and 90% of the buildings were damaged or destroyed. Damage estimates for St. Croix were astronomical, over $1 billion, and the island's entire infrastructure was virtually wiped out. Six weeks after the hurricane, only 25% of the public roads had been cleared, and only 25% of the island had power.
Figure 3. GOES visible satellite image of Hurricane Hugo taken on September 18, 1989. Note the lack of cloud cover on the hurricane's southwest side, indicating that strong upper-level winds from the southwest were likely creating wind shear, weakening the storm. Image credit: Google Earth rendition of the NOAA HURSAT data base.
As Hugo departed St. Croix, strong upper-level winds from the southwest created wind shear that weakened the storm to a Category 3 hurricane with 130 mph winds. The upper level winds also caused Hugo to accelerate to 15 mph and turn more northwest. The eye passed over Puerto Rico's Vieques Island at 8am and over Fajardo on the extreme northeastern tip of Puerto Rico at 9am. On Culebra Island, an island twelve miles east of Fajardo, a gust to 170 mph was recorded by the ship Night Cap in the main harbor. The south-facing harbor received sustained southerly winds in excess of 120 mph for several hours as Hugo roared by to the south. The resulting wave "set-up" created a storm surge in excess of 13 feet in the supposedly hurricane-proof harbor. A large portion of the Caribbean's charter boat fleet, some 200 boats, was sheltering in Culebra's harbor, and 136 of these boats were badly damaged or sunk. Over 80% of the wooden structures on both Culebra and Vieques were destroyed.
Figure 4. Damage on St. Croix (two top photos), Culebra Island (bottom right), and Puerto Rico's Roosevelt Roads Navy Base (bottom left), after Hurricane Hugo. Image credit: NOAA Photo Library.
Along the northeastern coast of Puerto Rico, waves up to ten feet high riding on top of a 3 - 4 foot storm surge caused severe coastal flooding of low-lying areas. Hugo's winds tore into Puerto Rico's El Yunque rainforest, downing thousands of trees. The agricultural sector was devastated, with nearly all of the island's banana and coffee crops wiped out. Twelve deaths in Puerto Rico were attributed to Hugo, six of which occurred in the southern city of Guayama where some residents were electrocuted by downed power lines. Nearly 28,000 people were left homeless by the storm, and damage to the island exceeded $1 billion.
Storm chaser Michael Laca was at Luquillo Beach on the northeast shore of Puerto Rico, and has posted a remarkable 28-minute video on YouTube of Hurricane Hugo footage.
Jeff Masters
Reader Comments
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The only vorticity in that area is in the 500mb range and definitely onshore...there's notyhing offshore by way of vorticity...maybe you're seeing cloud movement
I have never seen the middle of a system fall out like 98L just did on sat.animation.
That was neat to see and then the popup outside of the cloud mass.
wow.
Yes, it would. Closer to Daytona or the Cape, with the high building in to the north.
First thing's first, though... convection has to stick, and the center has to close off.
Dude May 1896?
Yes, but it will have to start developing pretty soon before it runs out of water. i dont think conditions favor a katrina scenario though.Just something to watch over the weekend.
154
fxus62 kmfl 181832
afdmfl
Area forecast discussion
National Weather Service Miami Florida
232 PM EDT Friday Sep 18 2009
Discussion...a weak trough is drifting west across the northern
Bahamas and the straights this afternoon along with a few weak
embedded vorts (one is located just south of the middle keys) while
an area of high pressure continues to ridge into the Gulf and
along the West Coast of Florida. Also, a cut-off low continues to mill
about Louisiana and another inverted trough (the weak remnants of
fred) is heading west and is located north of Puerto Rico. The
weak inverted trough located just S and east of S Florida will continue
to slowly head west bound this evening and eventually into S Florida
tonight. Scattered rain showers and thunderstorms and rain will increase along the East Coast
overnight and eventually spread across the rest of the County Warning Area as Sat
progresses while becoming more numerous as daytime heating occurs.
Behind this trof, and on Monday night and Sunday, the ridge is
expected to push back into the area from the north as the cut-off
low finally ejects out of the lower MS valley shoving the surface
ridge along the Atlantic Seaboard southward. As the ridge pushes
south this will keep the remnants of Fred on an eastward course
and eventually toward Florida. This is expected to increase rain
chances during the first portion of the week as the weakening system
pushes through. Behind the remnants of Fred and during the middle
and end of next week the ridge over the Atlantic is expected to
slowly sag southbound and increase the depth of the easterly flow.
This will allow nocturnal and morning rain showers and a few thunderstorms and rain along
the East Coast with afternoon and evening thunderstorms and rain along the West
Coast and over the interior, however guidance also indicates a
fairly strong middle level ridge settling in across the region which
may keep coverage fairly sparse at best.
That was an incredible tornado out break, here is a link for it. link
Maybe...I'm still a novice for sure, but I could swear there's something turning counter-clockwise just East of the "line" of clouds off the Coast there. The NHC isn't mentioning anything either, so I'm sure it's my eyes deceiving me.
Well, if you add to that the fact that it can't fight the high building in above it
98L has an nice low level circulation but thunderstorm activity is limited. The Hurricane models appear to have a poleward bias for this system and right now I am forecasting for the system to head in the general direction of the northern Lesser Antilles as a compromise between the hurricane models and the statistical BAM computer forecast models. Upper level winds only appear marginally favorable for development.
By AccWeather.com Expert Senior Meterorologist Paul Walker...
Even the biggest wishcaster out there thinks exFred is dead.
you obviously arent paying much attention to what is going on
Try going here:
Modeling Site; the CMC, GFS and NGP provide options for vorticity and shear, current and forecast. Typically not too bad and easier to see than some other sites
And no, I wasn't there at the time, either!!
Interesting, though. Look up June 1966 Topeka. I was in the army stationed in Ft. Riley, KS, near Manhattan at the time!
Tropical Cyclone Advisory #53
TYPHOON CHOI-WAN (T0914)
3:00 AM JST September 19 2009
=========================================
SUBJECT: Category Three Typhoon In Sea South Of Japan
At 18:00 PM UTC, Typhoon Choi-wan (965 hPa) located at 26.4N 139.6E has 10 minute sustained winds of 75 knots with gusts of 105 knots. The typhoon is reported as moving north-northeast at 12 knots
RSMC Dvorak Intensity: T4.5
Storm-Force Winds
=================
100 NM from the center
Gale-Force Winds
================
250 NM from the center
Forecast and Intensity
=======================
24 HRS: 31.8N 144.6E - 75 knots (CAT 3/Strong Typhoon)
48 HRS: 36.1N 151.7E - 55 knots (CAT 2/Severe Tropical Storm)
72 HRS: 38.3N 159.2E - Extratropical
Hey Drak. There has been some minor disagreement as to whether or not EX-FRED or 07L has a closed circulation or is an open wave. Where can we look to find the current data. I can not seem to find it! Do you believe it is closed based upon observation or information?
Conditions should be improving tonight into tomorrow for 07L to regenerate.
It will have..
5-15 knots of windshear
Very warm Gulf Stream water temps.
less dry air
So we'll see what happens, tomorrow will be an interesting day.
Afternoon Drak. According to the 12ZGFS Shear will be pristine ahead in 18 hours and an Upper level anti-cyclone over the bahamas in 30.
wow, that is intense! and yeah, didnt think you were that old ;)
here, check out on my blog, I have a couple of tornadoes listed that were relatively close to me, oddly enough, they both occurred in November 2005 link
If you look at the visible, you'll see a well defined circulation, which is closed. :)
THE REMNANTS OF TC FRED...A TIGHT LLVL SWIRL IN SATELLITE IMAGERY...WAS ALONG 26N67W THIS AFTERNOON...MOVING NW 15 KT. THE LOW LEVEL TROUGH THAT THIS FEATURE IS EMBEDDED WITHIN IS MOVING WNW AND EXPECTED TO MOVE IN THIS MANNER NEAR 15 KT AND VERY GRADUALLY SLOW...REACHING THE NW BAHAMAS IN 48 HOURS. A MORNING QUICKSCAT PASS STILL SHOWED 20-25 KT WINDS IN N SEMICIRCLE OF THIS SWIRL...WITH SEAS ESTIMATED 8 TO 10 FT WITHIN 240 NM N AND NE. AS THIS MOVES WNW...THE LOW IS EXPECTED TO OPEN UP INTO A MORE OBVIOUS TROUGH...THAT SHOULD MOVE NW REACHING THE SE FL COAST MON.
I see we now have 98L and ex-Fred is heading into better environmental conditions.
This is a bulk shear predicition based on 200-850mb, a thick slice of the atmosphere.
So far this season, the bulk shear has not been a very reliable indicator of cyclone development. Several storms have had apparently favorable bulk shear but were still killed by strong shear in small layers.
howdy!
Could not agree more.
I understand that it may not regenerate, but to say it's gonna open up to a trough in "favorable conditions".. I dunno about that one lol.
Visible imagery and microwave imagery. There are no surface observations close enough to the low pressure center to confirm a closed low using this tool.
I don't have any weather balloons so I, like the rest of us, will have to go by the tools that are available and the NHC guidance which both show favorable shear ahead ;-)
Isn't 07L, Fred?
again, thats been the trend this year - persistent lows from africa all the way to the caribbean (or conus?)
Yes, he's "Double 07L" ;)
Hey reed. Did see it but didn't want to mention it, because you-know-why? I guess it will be a wait and see, but I doubt it shall have enough time to get too strong, you think?
Just ahead is some favorable conditions, won't get there until tonight or tomorrow.
I think this will ramp up right before landfall into a TD or weak TS. Something similar to Claudette this year, just on the East Coast this time.
Perhaps the best answer all day, Thanks Drak.
We'll see.
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