TD 8 forms; 97L a potential threat to the Caribbean and U.S.
Tropical Depression Eight formed last night near the coast of Honduras, and is headed westwards towards a landfall in Belize on Saturday. TD 8 is a small storm, so will impact a relatively small area of northern Honduras, northern Guatemala, all of Belize, and southern portions of Mexico's Yucatan Peninsula. TD 8 has just enough room between its center and the coast of Honduras to intensify into a moderate strength tropical storm with 50 - 60 mph winds before landfall. It is very unlikely TD8 has the time or room to intensify into a hurricane; NHC gave the storm just a 7% chance of making it to hurricane strength in their 11am EDT wind probability forecast. Should TD8 make it to tropical storm strength, it would be called Harvey.
Figure 1. Morning satellite image of TD 8.
Invest 97L likely to become a tropical storm next week, could threaten the U.S.
A tropical wave near 14°N 48°W, about 800 miles east of the Lesser Antilles Islands, is moving westward near 20 mph. This wave, designated Invest 97L by NHC yesterday, has seen a marked increase in its heavy thunderstorm activity this morning, but dry air to the north and west is slowing development. An impressive amount of large-scale spin is obvious in visible satellite loops, but the storm is at least a day away from forming a well-defined surface circulation. Ocean temperatures are about 28.5°C, about 2°C above the threshold needed to support a tropical storm, and wind shear is low, 5 - 10 knots.
Figure 2. Morning satellite image of the tropical wave 97L.
The computer models have shown an unusual amount of agreement in developing 97L over the past few days, and all the ingredients seem to be in place for a tropical storm to form by Monday or Tuesday as 97L crosses the Northeast Caribbean. The atmosphere is expected to be moister over the Caribbean, wind shear will remain a low 5 - 10 knots, and sea surface temperatures will increase to near 29°C. The main impediment for development will likely be two-fold: too much dry, stable air, and proximity to land.
As seen in Figure 3, there has been an unusual amount of dry, stable air in the Atlantic this year, due to a combination of dry air from Africa, and upper-atmosphere dynamics creating large areas of sinking air that dry as they warm and approach the surface. This stable air has been largely responsible for the fact that none of our seven tropical storms so far this year has made it to hurricane strength, despite the presence of sea surface temperatures that are the 3rd warmest on record across the tropical Atlantic. Tropical Storm Emily in early August encountered problems with dry air when it crossed the Northeast Caribbean, and 97L may have similar difficulties.
Figure 3. Vertical instability of the atmosphere during 2011 in the Caribbean (left) and tropical Atlantic between the Lesser Antilles Islands and coast of Africa (right.) The instability is plotted in °C, as a difference in temperature from near the surface to the upper atmosphere. Thunderstorms grow much more readily when vertical instability is high. Observed vertical instability (blue line) has been much lower than the climatological average from previous years (black line), due to an unusual amount of dry air in the atmosphere, inhibiting tropical storm development this year. Image credit: NOAA/CIRA.
Encounters with land will be another potential major problem for 97L. Most of the computer models take 97L near or over Puerto Rico Sunday night, then very close to or over mountainous Hispaniola Monday night through Tuesday. It is unlikely that 97L will be stronger than a 55 mph tropical storm when it encounters these islands, and passage over the islands could severely disrupt the storm. However, if 97L takes a path just south or north of Hispaniola, the potential exists for the storm to intensify into a hurricane.
There will be moderate wind shear of 10 - 20 knots to the north of the islands early next week, so a path just to the south of the Dominican Republic and Haiti would be more likely to let 97L intensify into a hurricane. A west-northwest motion is likely for 97L through Wednesday, which would bring the storm to the vicinity of Jamaica-Central Cuba-the Central Bahamas on Wednesday. On Wednesday and Thursday, the models agree that a trough of low pressure will dip down over the Eastern U.S., which is likely to turn 97L to the north. The exact timing and strength of this trough varies considerably from model to model, and will be critical in determining where and when 97L will turn to the north. The best model for predicting the timing and strength of such troughs over the past two years has been the ECMWF (European Center model), and this model currently brings 97L into the Florida Keys on Thursday night next week. You can view ECMWF forecasts on our wundermap with the model layer turned on. The European Center does not permit public display of tropical storm positions from their hurricane tracking module of their model, so we are unable to put ECMWF forecasts on our computer model forecast page that plots positions from the other major models.
Remember that a 7-day forecast by even our best model will be off by an average of over 700 miles, so it is too early to tell what part of the U.S. might be most at risk from a strike by 97L. This weekend would be a good time to go over your hurricane preparedness.
Figure 4. Morning satellite image of Invest 98L off the coast of Africa.
Invest 98L near the coast of Africa
A tropical wave near the coast of Africa, a few hundred miles southeast of the Cape Verde Islands, is moving west to west-northwestward at 10 - 15 mph. This wave, designated Invest 98L by NHC yesterday, is large and well-organized, with a modest amount of spin and heavy thunderstorm activity. 98L will bring strong, gusty winds and heavy rains to the Cape Verde Islands today and Saturday as the storm skirts to the south. So far this morning, top sustained winds measured in the islands were 24 mph at Mindelo. Water temperatures are warm, near 27 - 28°C, and wind shear is low, 5 - 10 knots, so 98L should continue to organize today. NHC gave the storm a 50% chance of developing into a tropical depression in their 8am advisory. Once 98L passes to the west of the Cape Verde Islands, it has a long stretch of ocean to cross before it could affect any other land areas. Approximately 70 - 80% of all tropical cyclones that pass this close to the Cape Verde Islands end up curving out to sea and not affecting any other land areas, according to Dr. Bob Hart's excellent historical probability of landfall charts. The latest set of long-range model runs go along with this idea, but it is too early to be confident of this.
Jeff Masters
Reader Comments
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actually the pressures in the center on many models are too high for the storm they are showing, because they cannot handle the idea of a system with that low of a pressure
except the GFDL and HWRF of course, who can show sub 900 storms at times, the rest of the models rarely if at all show anything lower than 975
wow.. you lean something new everyday....thanks
Look closely under those squiggly lines. It is there. How is my aqua this morning?
NHC Official forecast tracks (OFCL) for Hurricane Ivan during the period 1800 UTC 02 through 0600 UTC 16 September 2004 (1st U.S.landfall). Note the persistent right-of-track bias from the outset as a result of most of the global models prematurely eroding the subtropical ridge to the north of the hurricane.
stay safe over there and let us know how it's going!
Thank you for the time you give us.
97L is looking good today and in the sweet spot between 55 and 60 W where weak systems have a tendency to close off a surface low. As I have posted before, from 55 to 63 W is the first window of opportunity for an easterly wave that has not developed to do so. 97L looks like it has a good chance of becoming a TD before 63 but that remains to be seen.
My estimate for the point of entry into the Caribbean was near 16 N and that still looks like a good bet, perhaps somewhere between 15 and 16 depending on whether it can close off a surface low sooner or later.
Later would tend to bring it in lower near 15, sooner closer to 16 IMO.
The low level steering now is due West to WNW all the way through the Caribbean ( see below ) so no recurve is expected for a long time down the road. If 97L does develop it could be a bull in a china shop, no way out without doing damage.
See post 3977.
The 4 more eastern line-segments represent TropicalStormHarvey's path
and the westernmost line-segment is the straightline projection.
Using straightline projection of the travel-speed&heading derived from the ATCF coordinates spanning the 6hours between 6amGMT then 12pmGMT :
TS.Harvey's travel-speed was 15.2mph(24.4k/h) on a heading of 287.9degrees(WNW)
TS.Harvey was headed toward passage over MullinsRiver,Belize ~4&1/3 hours from now
Copy&paste sjx, 16.0n83.3w-16.1n84.0w, 16.1n84.0w-16.1n84.7w, 16.1n84.7w-16.3n85.7w, 16.3n85.7w-16.7n87.0w, mdb, 16.3n85.7w-17.09n88.29w into the GreatCircleMapper for more info
The previous mapping (for 20August_6amGMT)
XXL/XX/INV97
MARK
14.77N/55.19W
Thank you, aqua. It is my pleasure. I just want you to know that I have had some happy times on the Doc's blog because of all of you.
LOL...Agree....but put almost no weight in it. NONE, Way to early and u should know that. While I wasnt their last night, I just spoke to someone who was and the forecasters at the NHC commented quite a bit on 97L with relation to the consistent model runs. Quite a few opinions but almost all used terminology like "if it survives", "whats left of it" and "it may not amount to a whole lot" etc, etc, with relation to a path thru the Bahamas or Florida after exiting the islands. Dont get me wrong all are concerned as we should be. As I mentioned earlier there was a lot of examples thrown around such as huge powerful Hurricanes such as Cleo in 64 (cat4) and David 1979 (cat 5) amongst others which were nothing compared to what they were prior to going thru the Islands. Cleo (cat 4) stayed south of the islands and turned north over east central cuba and weakened significantly prior to hitting Florida.....a path 97L could possibly take. As a matter of fact, you should take a look at that path. Very Very similar to what the models are suggesting 97L may do. David is also a very possible track. The islands tore up David after killing 2000 and being a cat 5 hurricane, prior to hitting florida as a weak disorganized barely cat 2.
(~ 24.88 inHg) 1,561 meters
(~ 5,121 feet) 1008.7 mb
(~ 29.79 inHg) - From 43° at 21 knots
(From the NE at ~ 24.1 mph) 17.0°C
(~ 62.6°F) 12.9°C
(~ 55.2°F) 22 knots
(~ 25.3 mph) 95 knots*
(~ 109.2 mph*) 1 mm/hr*
(~ 0.04 in/hr*) 90.7 knots* (~ 104.3 mph*)
Category Two Hurricane*
431.8%*
NHC just threw this one out there to see the reaction of people from this site lmao
I always remembered Ivan when I looked at the roof of my house that burned down. I had shingles from a friend in Ocean Breeze who had to have a new roof put on. They only got it put on just before Rita hit us here. She brought me her leftover shingles for me to put on my house as there were no shingles even six months after Rita to redo the needed areas on mine.
Back to topic.....
97L is doing well.
I love your screen name. :)
all news channels doitto keep everyone calmwhen they need to panic.... the DOOM is there
WTH!!!!
08L/TS/H/CX
APPROACHING LANDFALL
Direct Hit:
A close approach of a tropical cyclone to a particular location. For locations on the left-hand side of a tropical cyclone's track (looking in the direction of motion), a direct hit occurs when the cyclone passes to within a distance equal to the cyclone's radius of maximum wind. For locations on the right-hand side of the track, a direct hit occurs when the cyclone passes to within a distance equal to twice the radius of maximum wind. Compare indirect hit, strike.
Strike:
For any particular location, a hurricane strike occurs if that location passes within the hurricane's strike circle, a circle of 125 n mi diameter, centered 12.5 n mi to the right of the hurricane center (looking in the direction of motion). This circle is meant to depict the typical extent of hurricane force winds, which are approximately 75 n mi to the right of the center and 50 n mi to the left.
13 Names remain 2011 Atlantic Storm Name List
Irene Jose Katia Lee Maria Nate Ophelia Philippe Rina Sean Tammy Vince Whitney
news channel 8
It has been proven a bull in a china shop is very careful. I would say, more like a london rioter in a china shop.
Good synopsis. Can't find much wrong there. Probable scenario and kept it simple for people like me.
Of all the past hurricanes being discussed at this time as possible analogs, Charley and Frederick may be the ones that most closely resemble what 97L will do out past 72 hours. That type of track for 97L would be worst case, of course, as the GoM is on fire.
Even still, the thing could come ashore anywhere along the eastern Gulf Coast, the boot heel of the FL peninsula, or the SE coast of FL.
I would say only slightly unusual. Basically the models are not picking up on an extremely complex and confusing environment for this storm. They are all initialized with very similar data and their algorithms just handle the data a little differently. That said; I think the only thing that can be taken from the models right now is that the basic shape of the track is fairly reliable. It will head WNWish and there will be a turn to the N at some point. I would not be surprised if it were a fish storm or if it ended up in La. If it made a beeline for Mexico or Texas; I would be shocked though.
The world is a better place today due to the Mythbusters....lol.
It's an invest...not even a TD. You are a real drama queen aren't you?
Looking at the forecast steering out to Wednesday next week 97L should be somewhere between us and Cuba. For now I am leaning towards this going just N of Jamaica near CB and LC then WNW across Western Cuba.
Of course, this is long range and subject to change depending on many current unknowns, not the least of which is that we do not have a TD as yet. The entry point into the Caribbean is fairly low due to the fact that it has taken a long time to ramp up and my estimate of the track could shift farther West and South depending on if and when it is classified as a TD.
With the TCHP levels where they are in the Caribbean this needs to be carefully monitored.
Glad you guys are all okay.
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