Tropical Depression Seven forms

By: Dr. Jeff Masters , 2:25 PM GMT on August 14, 2011

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The latest in our unusual number of weak tropical cyclones this season, Tropical Depression Seven, has formed to the southeast of Bermuda. Unless you live in Bermuda, TD 7 is not going to be a concern. Radar out of Bermuda shows an area of rain on the northern side of TD 7 beginning to approach the island, and rain from the storm will likely affect the island tonight and on Monday. TD 7 is not well-organized, and has only limited heavy thunderstorms, as seen on visible satellite images. While wind shear is a low 5 - 10 knots, dry air surrounds TD 7, and is keeping the storm from intensifying. None of the computer models foresee that TD 7 will ever become more than a weak tropical storm.


Figure 1. Morning satellite image of TD 7.

92L
TD 7 isn't the only system Bermuda needs to watch, Invest 92L is a day behind it, and will follow a path very similar to TD 7's. The disturbance will pass close to Bermuda on Tuesday, bringing the island a second round of tropical rains. However, Invest 92L is very disorganized, as seen on recent visible satellite loops. Dry air and close proximity to TD 7 will likely keep 92L from showing significant development over the next two days, with NHC giving the system just a 30% chance of developing into a tropical depression by Tuesday morning.

Elsewhere in the tropics
The disturbance midway between the Lesser Antilles Islands and the coast of Africa we've been tracking over the past few days, Invest 93L, has fallen apart and is no longer a threat to develop. This system will need to be watched once it enters the Caribbean later this week, though. None of the reliable models for predicting tropical cyclone formation predict development of this system or any new disturbances over the coming week.

Jeff Masters

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Quoting OrchidGrower:
re: 1917, AtHomeInTX --- it's this stuck pattern that makes me wonder if we're going to see any change from the weak tropical systems now appearing. If the pattern's stuck here, is it not stuck over Africa and the tropical Atlantic as well? Only thing I see noticeably different in the last 3 weeks is that suddenly we're not firing off major hurricanes in the EPAC. The African waves are still coming off looking amazing, then falling apart in the parched air over the ATL.


I don't know if we're going to see this high back off or breakdown. I can hope so at some point. Although with La Nina supposed to come back could keep us dry through the winter. UGH! As far as the EPAC picking up, I think the MJO has been moving through making the environment more conducive for storms. And I think it's now coming into our basin too. May help getting things going in the Atlantic too.
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For your tropical flavored listening pleasure while blogging:Link
Member Since: August 13, 2007 Posts: 0 Comments: 10492
the HH should fly in to 93L sometime soon they need to they are going to do it either east of the windwards or west of the windwards
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1922. rod2635
Quoting P451:


Was always intrigued by Hawaii's buffer zone. To get a hurricane they have to form to the south and come north through the islands.

I think there may have been one system on record that was a weak hurricane that made the trek and came in from the ESE.

Everything just rapidly dies off when it gets within a day or two of the Island from the ESE. Water temps are one thing but there always seems to be a pocket of strong shear that forms between the islands and the approaching storm as well.





Perhaps that's why the model runs seem to flat line at 145 longitude...low confidence of further westerly track?
Member Since: January 27, 2011 Posts: 0 Comments: 396
1921. ncstorm
Quoting AtHomeInTX:


Been waiting all night for that to work. Lol. Looks like they still take a piece of that GOM front and bring it to TX. Would be nice if the ridge doesn't kill it. AGAIN.


if anything, we can say the ECWMF has been consistent in showing that piece of energy and thats saying a whole lot when it comes to the models lately..hopefully texas can get some relief in precip..
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re: 1917, AtHomeInTX --- it's this stuck pattern that makes me wonder if we're going to see any change from the weak tropical systems now appearing. If the pattern's stuck here, is it not stuck over Africa and the tropical Atlantic as well? Only thing I see noticeably different in the last 3 weeks is that suddenly we're not firing off major hurricanes in the EPAC. The African waves are still coming off looking amazing, then falling apart in the parched air over the ATL.
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Quoting P451:


DMax has already run it's course.
93L is highly unlikely to develop prior to the islands.
Therefore it's next window of opportunity is beyond 70W.
I think you can rest assured that a Cat 5 is not coming to the Cayman Islands.
Although we all know that won't stop you from predicting every cloud in the Atlantic to have a high chance of doing so.


Actually he said he couldn't wait to see what Dmax would bring this morning and he knew it would look better and be reactivated. He did not say anything about a Cat 5 coming to Cayman and furthermore the current predicted paths DO bring it over or very near the Cayman Islands. No reason for you to continuously talk down to people.
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Quoting ncstorm:
00Z ECWMF still has development of the African wave

Link


Been waiting all night for that to work. Lol. Looks like they still take a piece of that GOM front and bring it to TX. Would be nice if the ridge doesn't kill it. AGAIN.
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Hmmm. Kinda interesting from Houston. Says the high may be moving west but the models show no relief. Guess we'll see. Any rain would be nice. :)

SHOULD
SEE THE RIDGE EDGE WESTWARD LATER IN THE WEEK. IF THIS HAPPENS...
THE AREA COULD SEE A SLIGHT LOWERING OF TEMPERATURES ALONG WITH A
GRADUAL INCREASE IN RAIN CHANCES. EXTENDED MODELS DO NOT INDICATE
ANY SIGNIFICANT PATTERN CHANGE THAT WOULD BRING US ANY BENEFICIAL
RAINS AND A MUCH NEEDED DROP IN TEMPERATURES. THE DROUGHT AND THE
RECORD BREAKING SUMMER HEAT CONTINUES.

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Quoting P451:


That depends what it's target is. Is it NOLA? If so, yes, DOOM has been declared.

Joking aside...

Out of curiosity, what do you see the hurricane forming from?


93L... and its not going to take a week according to the models.
Member Since: October 1, 2007 Posts: 81 Comments: 26516
1915. scott39
Goodmorning, Isnt the high going to slide more to the W, and cause a weakness in the central/northern GOM?
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Complete Update

TS BUSTED FORECAST ALIBI






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1913. ncstorm
00Z ECWMF still has development of the African wave

Link
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1911. Patrap
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1910. Patrap
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1908. Patrap
12z Early Cycle NHC model tracks
Gert
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)


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1907. Patrap
Making humor of calamity is the WORST form of Humor here.

Always
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You should only be interested in Gert if you are a fisherman.
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Quoting KennyNebraska:


That is not what this says.



In my view its highly unlikely this system gets into the gulf. Rediculous ridge over texas should prevent much northward progression. Both the european and gfs global models take this into central america which looks like a good forecast to me at this time.
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We are all so focused on 93L that nobody has noticed that recon has already penetrated Gert and is giving back data.
Member Since: May 27, 2009 Posts: 0 Comments: 4438
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 15th day of the month at 12:07Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 303)
Storm Number & Year: 07L in 2011
Storm Name: Gert (flight in the North Atlantic basin)
Mission Number: 2
Observation Number: 07
A. Time of Center Fix: 15th day of the month at 11:42:40Z
B. Center Fix Coordinates: 31°28'N 63°16'W (31.4667N 63.2667W)
B. Center Fix Location: 107 miles (172 km) to the ESE (123°) from Hamilton, Bermuda (GBR).
C. Minimum Height at Standard Level: 1,440m (4,724ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 51kts (~ 58.7mph)
E. Location of the Estimated Maximum Surface Wind: 10 nautical miles (12 statute miles) to the E (90°) of center fix
F. Maximum Flight Level Wind Inbound: From 194° at 52kts (From the SSW at ~ 59.8mph)
G. Location of Maximum Flight Level Wind Inbound: 14 nautical miles (16 statute miles) to the E (95°) of center fix
H. Minimum Sea Level Pressure: 1002mb (29.59 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 18°C (64°F) at a pressure alt. of 1,535m (5,036ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 23°C (73°F) at a pressure alt. of 1,519m (4,984ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 10°C (50°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Open in the east
M. Eye Shape & Diameter: Circular with a diameter of 8 nautical miles
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 0 nautical miles
Remarks Section:
Maximum Flight Level Wind: 52kts (~ 59.8mph) in the east quadrant at 11:38:10Z
Maximum Flight Level Temp: 25°C (77°F) which was observed 8 nautical miles to the E (87°) from the flight level center

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Quoting P451:


Shall we predict doom like what was done with 92 and 93?

Or shall we all be a bit wiser and look for persistence and organization?

:)


I predict a nice sized hurricane in the GoM in about a week from now.

Does that translate to doom?
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Quoting hurricane23:


No real change in the pattern over the next 7-10 days, trough across the eastern US with ridging across the central US which implies that any storm tracking north of the Antilles should recurve east of the US or a threat to the eastern US if ridging builds in stronger before the trough settles down again.


That is not what this says.

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Quoting KennyNebraska:
The current model tracks for 93L are disconcerting. The GoM is full of very hot water.


No real change in the pattern over the next 7-10 days, trough across the eastern US with ridging across the central US which implies that any storm tracking north of the Antilles should recurve east of the US or a threat to the eastern US if ridging builds in stronger before the trough settles down again.
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1873. blsealevel

Too bad that webpage is not kept up to date, still listing biases from 10 years ago.
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1890. ncstorm


two highs..one in the GOM and one on the East Coast of Fl which will lead to a westward motion for 93L if develops..
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AL, 93, 2011081506, 133N, 547W, 20, 1011, WV
AL, 93, 2011081512, 135N, 564W, 25, 1010, WV
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1888. ncstorm


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93L looks good at this AM I told you guys I can't wait to see what D-Max has in store for 93L this morn cause I knew that we would have a reactivation and I knew when that models run it will be taking it here to me sadly
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1886. SLU
Quoting CaicosRetiredSailor:
Another piece of the 2011 puzzle:
Surface currents

Quote from AntiguaIsland,blogspot:

We had months of unusual south currents and many of us who were fishing in May and June complained about these currents. It seems as though they hit the Sargasso Sea at a strange angle possibly pushing some of the weed away from what is normally a current free area within the north Atlantic gyre. Its as if - in a swirl - masses of sargassum broke off and probably went north and east into the currents which now have brought the weeds back across from Africa into the Caribbean. People from Tobago to Hispaniola are complaining about masses of weeds. This photo below taken by a friend shows what is normally a nice little windward bay on the Eastern side of Antigua. As you can see, the dock is now surrounded by sargassum.


http://antiguaisland.blogspot.com/2011/08/sargass um-come-ashore-in-unprecedented.html



We've had this same sea weed problem in St. Lucia this year too. I saw some of it this morning but thank to 93L, visibility is near 0.
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Quoting stormwatcherCI:
This is weird. The sea and shore in East End, Grand Cayman is covered with this. Never saw it like that before.


Not to mention South Sound! Worse I've seen since I was a young boy!
Member Since: April 29, 2007 Posts: 0 Comments: 8134
Quoting GeoffreyWPB:


Ok. Everything's back to normal now. Nothing can come up this way. Strait into Mexico it is. :)
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Member Since: May 27, 2009 Posts: 0 Comments: 4438
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Wave fresh in the water....

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Didn´t Emily look just like 93L when approaching the islands (A double entity) ?

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Interesting gale in the North Atlantic later this week:





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I am heading out now so everyone have a nice morning. Will look in later to see how things are going.
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1876. emcf30
* ATLANTIC SHIPS INTENSITY FORECAST *
* GOES AVAILABLE, OHC AVAILABLE *
* INVEST AL932011 08/15/11 12 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 25 27 29 32 36 45 53 62 68 74 78 81 82
V (KT) LAND 25 27 29 32 36 45 53 62 68 71 75 78 79
V (KT) LGE mod 25 28 30 33 36 41 48 54 63 68 79 88 96
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 3 3 9 13 15 8 18 12 18 10 15 14 17
SHEAR ADJ (KT) -2 -2 -3 -4 -2 -1 -3 -5 -6 -5 -2 -3 -1
SHEAR DIR 181 270 258 282 302 268 281 293 301 293 287 285 303
SST (C) 28.9 29.0 29.1 29.0 29.0 28.9 28.7 28.8 29.2 29.6 29.7 29.9 29.8
POT. INT. (KT) 153 154 156 154 154 153 149 150 156 163 164 168 166
ADJ. POT. INT. 158 158 160 159 159 156 151 149 154 158 158 160 156
200 MB T (C) -53.9 -53.6 -53.6 -53.5 -53.4 -53.2 -53.2 -52.8 -53.2 -52.7 -53.1 -52.4 -52.6
TH_E DEV (C) 11 12 12 12 12 13 12 13 12 12 11 12 11
700-500 MB RH 52 51 48 48 50 49 51 52 54 60 63 60 59
GFS VTEX (KT) 0 LOST LOST LOST LOST LOST LOST LOST LOST LOST LOST LOST LOST
850 MB ENV VOR 19 29 23 22 35 46 29 46 37 37 19 15 9
200 MB DIV -4 0 -2 6 23 36 2 18 21 11 7 15 -2
700-850 TADV 3 0 2 -2 -5 5 5 1 1 -4 0 0 0
LAND (KM) 582 462 386 379 411 303 254 155 54 30 277 321 221
LAT (DEG N) 13.5 13.8 14.0 14.2 14.4 15.2 15.9 16.7 17.4 18.0 18.6 19.1 19.7
LONG(DEG W) 56.4 58.0 59.6 61.3 63.0 66.4 69.8 72.9 75.9 78.5 80.9 83.1 85.2
STM SPEED (KT) 17 16 16 17 17 17 16 15 14 12 11 11 10
HEAT CONTENT 70 77 75 80 73 79 104 93 97 115 113 120 127
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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