Tropical Depression Seven forms
Tropical Depression Seven is here. Looking remarkably like the tropical depression that became Tropical Storm Ernesto on August 1, TD 7 has a limited region of heavy thunderstorms, as seen on satellite loops. A large amount of dry air to the west and north is visible on water vapor satellite loops, and this dry air is interfering with TD 7's heavy thunderstorms. Wind shear is a light 5 - 10 knots, which is quite favorable for intensification. Ocean temperatures are 26°C, which is a bit on the cool side, though. Winds at the Middle Atlantic buoy 41041 were 20 mph at 5 pm EDT, and should rise this evening, as the center of TD 7 passes about 50 miles to the south near midnight. The first hurricane hunter mission into TD 7 is scheduled for Saturday morning.
Figure 1. Satellite image of TD 7 as it was forming at 3:17 pm EDT August 9, 2012.
Forecast for TD 7
TD 7 formed about 400 miles east-northeast of where Ernesto became a tropical depression, as seen on our wundermap. Atmospheric and oceanic conditions are currently quite similar to what Ernesto experienced, and I expect TD 7 will struggle with dry air like Ernesto did. The SHIPS model predicts that shear will remain light through Friday then rise to the moderate range on Saturday, when the storm will encounter moderate shear from upper-level westerly winds associated with a trough of low pressure. Since conditions are so similar to what Ernesto experienced, the official NHC forecast of a 45 - 50 mph tropical storm moving through the Lesser Antilles Islands Saturday and Sunday is a reasonable one.
Jeff Masters
Reader Comments
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MinimumPressure increased from 1008millibars to1009millibars
MaxSusWinds held at 30knots(35mph)56km/h
Vector changed from 266.8*West@19.1mph(30.7km/h) to 270.3*West@25.8mph(41.5km/h)
POS-Trinidad :: GND-Grenada :: BGI-Barbados :: SLU-St.Lucia
The easternmost dot on the kinked line is where 92L became a LOw again
The westernmost dot on the kinked line is where 92L became AL07
The next dot to the right is where AL07 became TD.7
The easternmost dot on the longest line is TD.7's most recent position
The longest line is a straightline projection through TD.7's 2 most recent positions to its closest approach (within 18miles or 29 kilometres) to a coastline
9August12pmGMT: AL07 had been headed for passage over SangreGrande (rightPOSdumbbell)
9August6pmGMT: TD.7 had been headed for passage over GrantleyAdamsInternationalAirport (bottomBGIblob)
10August12amGMT: TD.7 had been headed for passage over Bathsheba (middleBGIblob)
10August6amGMT: TD.7 had been headed for passage over HighCliffPoint (topGNDdumbbell)
10August12pmGMT: TD.7 was heading for passage over LittleBay in ~1day3hours from now (when this comment was posted)
Copy&paste pos-10.595n61.023w, bgi-13.09n59.457w-13.198n59.488w, gnd-12.191n61.602w, slu, 12.1n31.2w- 12.7n32.5w- 13.3n33.9w- 13.9n35.4w- 14.1n37.0w- 14.1n38.5w- 13.9n40.0w- 13.7n41.7w, 13.7n41.7w-13.7n42.9w, 13.7n42.9w-13.7n44.6w, 13.7n44.6w-13.6n46.3w, 13.6n46.3w-13.6n48.6w, 13.6n46.3w-13.31n59.579w into the GreatCircleMapper for a larger-scale map and other information
The previous mapping for comparison
Click for loop.
NOGAPS did well with genesis of Ernensto and GFS was pretty accurate once it was formed, but failed to form it correctly in the beginning. So I guess we could try rely on those two for reference only of course.
ok that make more sense
No mention of 'vertical instability'. Sinking air was proposed as a reason why many storms failed to develop as expected in 2011. It's there agein, this year, probably as a result of the drought.
sorry dude but you are going to need to do some recalculations
AL, 07, 2012081012, , BEST, 0, 136N, 486W, 30, 1009, TD,
Nice looping pic.Aussie..
By the way I always thought you Austrailans have the coolest names for cities.. :)
look at the mode runs
It's over 2,000 miles away. Way too early to speculate. Check back every once in a while. IMO, TD7 doesn't make it. It is a small system with a lot of obstacles in front of it. If it does survive and reaches the western Caribbean then it may have a chance with better conditions. Much like Ernesto.
Who is saying that??
TD 7 Likely To Be Gordon
Invest93
The next system is a tropical wave currently passing through the Cape Verde Islands. This system has a ball of thunderstorms associated with it, but it has moved off rather far to the north around 17N. Most waves in this position unless they move WSW, traditionally have little chance of affecting land. This system could strengthen into a depression or storm in the next several days, most of the global models show this as well as the tropical models. But a WNW track looks likely and all the global data suggests a large trough over the eastern US next week would move into the western Atlantic and re-curve this system. I will watch it though.
Don't get ahead of yourself...
The NHC.
Pretty uncommon.
Best Track Position and Intensity as of:
Friday, August 10, 2012 12:00 Z
Location at the time:
208 statue miles (336 km) to the ENE (69°) from Praia, Cape Verde.
Wind (1 min. avg.):
30 knots (~35 mph | 15 m/s | 56 km/h)
Pressure:
1004 mb (29.65 inHg | 1004 hPa)
Coordinates:
16.0N 20.6W
Source:
National Hurricane Center's (NHC) Automated Tropical Cyclone Forecasting (ATCF) System and not from any available advisory data
Best Track Position and Intensity as of:
Friday, August 10, 2012 12:00 Z
Location at the time:
742 statue miles (1194 km) to the E (87°) from Bridgetown, Barbados.
Wind (1 min. avg.):
30 knots (~35 mph | 15 m/s | 56 km/h)
Pressure:
1009 mb (29.80 inHg | 1009 hPa)
Coordinates:
13.6N 48.6W
Source:
National Hurricane Center's (NHC) Automated Tropical Cyclone Forecasting (ATCF) System and not from any available advisory data
Not surprising really
Ernesto pt.2
further N however
THE CYCLONE IS FORECAST TO MOVE OVER INCREASING SSTS AND REMAIN IN
A LOW SHEAR ENVIRONMENT DURING THE NEXT DAY OR SO. HOWEVER...DRY
AIR NEAR THE CIRCULATION WILL LIKELY ALLOW FOR ONLY MODEST
INTENSIFICATION. THE GLOBAL MODELS INDICATE THAT THE DEPRESSION
WILL ENCOUNTER INCREASING SOUTHERLY TO SOUTHWESTERLY UPPER-LEVEL
WINDS AS IT NEARS THE WINDWARD ISLANDS. THIS INCREASING SHEAR WILL
LIKELY HALT ANY INTENSIFICATION. THE OFFICIAL INTENSITY FORECAST
IS SIMILAR TO THE PREVIOUS ADVISORY AND IS CLOSEST TO THE SHIPS
GUIDANCE. IT SHOULD BE NOTED THAT BOTH THE GFS AND ECMWF WEAKEN
THE SYSTEM AND SHOW IT BECOMING AN OPEN WAVE IN THE EASTERN
CARIBBEAN. FOR NOW...THE NHC FORECAST DOES NOT INDICATE
WEAKENING...BUT THAT IS ONE POSSIBILITY GIVEN THAT THE SYSTEM IS
SMALL...MAKING IT MORE PRONE TO THE EXPECTED INCREASE IN SHEAR
IN A COUPLE OF DAYS.
maybe not they could shift a little further north but we wait and see dont think that track is cut and dry
only by a few degrees.still forecast to pass south of Jamaica and the OHC/TCHP hot zone
THE DEPRESSION CONTINUES MOVING QUICKLY WESTWARD OR 270 DEGREES AT
17 KT. THE CYCLONE IS EXPECTED TO REMAIN ON THIS GENERAL HEADING
AND SPEED DURING THE NEXT FEW DAYS AS IT IS STEERED WESTWARD BY A
MID-LEVEL RIDGE OVER THE CENTRAL ATLANTIC. BEYOND THREE DAYS THE
RIDGE IS EXPECTED TO WEAKEN WHICH WOULD CAUSE THE CYCLONE TO TURN
WEST-NORTHWESTWARD. THE NHC FORECAST REMAINS ALONG THE SOUTHERN
SIDE OF THE GUIDANCE ENVELOPE AND IS IN BEST AGREEMENT WITH THE
GFS MODEL.
A LARGE AREA OF DISTURBED WEATHER ALONG THE SOUTHERN COAST OF MEXICO
IS ASSOCIATED WITH THE BROAD CIRCULATION OF WEAKENING TROPICAL
DEPRESSION ERNESTO. ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR THIS
DISTURBANCE TO DEVELOP AS IT MOVES WESTWARD AWAY FROM THE COAST OF
MEXICO. THERE IS A HIGH CHANCE...60 PERCENT...OF TROPICAL CYCLONE
FORMATION DURING THE NEXT 48 HOURS.
Goodbye, really? Won't the remnants of Earnesto cross Mexico and the Pacific, become a typhoon, cross IndoChina, and then those remnanats cross the Indian Ocean, cross Africa and become 146L? ??? Just kidding all the kiddos in here.
Think Globally, Act Locally. :P
It will stay Ernesto. It will only change names if the L dissipates. Which it hasn't.
Trade winds are strong. TD-5/Ernesto had the same problem, If TD-5/Ernesto had of been going slower he would become a bigger threat than he did, and a possible GOMcane
What's the difference between low-level circulation and mid-level circulation? The NHC said the low level circ. will dissipate, but the mid level circulation will survive the crossing and regenerate into a TD.
Healthy blob in the Carribean
What? Haven't you heard? Bird is the word.
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