Unusually well-organized 92L disturbance may become a tropical depression

By: Dr. Jeff Masters , 2:14 PM GMT on June 14, 2010

Share this Blog
3
+

Invest 92L, a remarkably well-developed African tropical wave for so early in the season, is midway between Africa and the Lesser Antilles Islands. Infrared satellite loops show a modest area of heavy thunderstorms along the north side of 92L's center of circulation, and the storm's heavy thunderstorms activity appears to be slowly increasing in intensity and areal coverage. Upper-level outflow is apparent to the west and north of 92L, and the outflow has been gradually improving this morning. Visible satellite loops do not show much in the way of low-level spiral bands, and my current take from the satellite imagery is that 92L is slowly organizing, and will not become a tropical depression any earlier than 11pm EDT tonight (Monday.) A 4:27 am EDT pass from the WINDSAT satellite saw a partially closed circulation at the surface (open on the south side), with top surface winds of 25 - 30 mph north of the center.


Figure 1. Morning satellite image of Invest 92L (left side of image) and a vigorous new tropical wave that has moved off the coast of Africa (right side.) None of models develop the new tropical wave, but it bears watching.

Sea surface temperatures
Climatology argues against development of 92L, since only one named storm has ever formed between Africa and the Lesser Antilles Islands in the month of June--Tropical Storm Ana of 1979 (Figure 2). However, sea surface temperatures (SSTs) underneath 92L are an extremely high 28°C, and will increase to 29°C by Thursday. In fact, with summer not even here, and three more months of heating remaining until we reach peak SSTs in the Atlantic, ocean temperatures across the entire Caribbean and waters between Africa and the Lesser Antilles are about the same as they were during the peak week for water temperatures in 2009 (mid-September.)

Dry air not a problem for 92L until Wednesday
The disturbance doesn't have to worry about dry air today or Tuesday--Total Precipitable Water (TPW) loops show a very moist plume of air accompanies 92L, and water vapor satellite loops show that the center of 92L is at least 200 - 300 miles from any substantial areas of dry air. As 92L continues to push northwest, though, the SHIPS model is predicting that relative humidity at middle levels of the atmosphere will fall from the current value of about 70%, to 60% on Wednesday. This dry air may begin to cause problems for 92L on Wednesday, especially since wind shear will be increasing at the same time. Tropical cyclones are more vulnerable to dry air when there is substantial wind shear, since the strong winds causing the shear are able to inject the dry air deep into the core of the storm.

Madden-Julian Oscillation
The 60-day cycle of enhanced thunderstorm activity called the Madden-Julian Oscillation is currently favoring upward motion over eastern tropical Atlantic, and this enhanced upward motion helps create stronger updrafts and higher chances of tropical cyclone development.


Figure 2. Tropical Storm Ana of 1979 was the only June named storm on record to form between Africa and the Lesser Antilles Islands.

Wind shear
A major issue for 92L, like it is for most June disturbances, is wind shear. The subtropical jet stream has a branch flowing through the Caribbean and tropical Atlantic north of 10° N that is bringing 20 - 40 knots of wind shear to the region. Our disturbance was located near 10°N, 40°W at 8am EDT this morning, a few hundred miles south of this band of high shear, and is currently only experiencing 5 - 10 knots of shear. This low amount of shear should allow for some steady development of 92L over the next two days as it tracks west-northwest or northwest at 15 mph. The latest run of the SHIPS model is predicting the shear will rise to 20 knots on Wednesday, which may start to cause problems for 92L.

The forecast for 92L
The National Hurricane Center is giving 92L a high (60% chance) of developing into a tropical depression by Wednesday morning, which is a reasonable forecast. The odds of development have increased since yesterday, as the storm has moved considerably to the northwest, away from the Equator. Now it can leverage the Earth's spin to a much greater degree to help get it get spinning. It is quite unusual for a tropical depression to form south of 8°N latitude.

I expect that 92L's best chance to become a tropical depression will come on Tuesday, and the storm could strengthen enough by Wednesday to be named Tropical Storm Alex. The farther south 92L stays, the better chance it has at survival. With the system's steady west-northwest movement this week, 92L will probably begin encountering hostile wind shear in excess of 20 knots by Wednesday, which should interfere with continued development. Several of our reliable models do develop 92L into a tropical storm with 40 - 55 mph winds, but all of the models foresee weakening by Thursday or Friday as 92L approaches the Lesser Antilles Islands and encounters high shear and dry air. I doubt 92L will be anything stronger than a 45 mph tropical storm when it moves through the northern Lesser Antilles Islands on Friday and Saturday, and it would be no surprise if wind shear has destroyed the storm by then. However, as usual, surprises can happen, and the GFS and the SHIPS model (which is based upon the GFS) do indicate that more modest levels of wind shear in the 15 - 20 mph range late this week may allow 92L to stay stronger than I'm expecting. Residents of the islands--particularly the northern Lesser Antilles--should follow the progress of 92L closely, and anticipate heavy rains and high winds moving through the islands as early as Thursday night.

Oil spill wind forecast
There is little change to the oil spill wind forecast for the coming two weeks. Light winds of 5 - 10 knots mostly out of the south or southeast will blow in the northern Gulf of Mexico all week, according to the latest marine forecast from NOAA. These winds will keep oil near the coast of Louisiana, Alabama, Mississippi, and the extreme western Florida Panhandle, according to the latest trajectory forecasts from NOAA and the State of Louisiana. The long range 8 - 16 day forecast from the GFS model indicates a typical summertime light wind regime, with winds mostly blowing out of the south or southeast. This wind regime will likely keep oil close to the coastal areas that have already seen oil impacts over the past two weeks.

Jeff Masters

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1091 - 1041

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64Blog Index

Quoting KEEPEROFTHEGATE:
93L is not to far away there is something special about this season that may even make 2005 look not as special anymore
I agree.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting MiamiHurricanes09:
Agreed. Can you imagine September?


I would expect cooler SSTs in September if we are going to have a wicked season starting relatively soon.
Member Since: Posts: Comments:
1088. KEEPEROFTHEGATE (Mod)
Quoting Levi32:


Nono....this isn't something you think of as a trend for waves getting torn apart. This wave shouldn't even BE as developed as it is...period. It's the opposite of what you are saying. This is the start of a trend for waves to develop. Having them try to pop this early and this far east is insane.
93L is not to far away there is something special about this season that may even make 2005 look not as special anymore
Member Since: Posts: Comments:
1086. IKE
Buoy 42039...115NM ESE of Pensacola...Water Temperature (WTMP): 89.4 °F


Buoys in the western GOM in the 80's....low to mid.

90 degree water temp at Fresh Water Canal Locks in Louisiana.
Member Since: Posts: Comments:
Quoting Levi32:


Nono....this isn't something you think of as a trend for waves getting torn apart. This wave shouldn't even BE as developed as it is...period. It's the opposite of what you are saying. This is the start of a trend for waves to develop. Having them try to pop this early and this far east is insane.
Agreed. Can you imagine September?
Member Since: September 2, 2009 Posts: 130 Comments: 21194
I know all the ingredients are there and all that hype but wasn't 2009 suppose to be an active season...and i know what you will say...El Nino yes i know that as well as anyone...and i know there isnt much of a spot for divine intervention in Meteorology but if there is a gracious God hopefully the Gulf Coast will be spared this year...I have visions of all that oil getting pushed inland..
Member Since: Posts: Comments:
1083. JDSmith
Okay, this is the year of the Hypercane AND the largest Oil Spill in US history.

Gotta love the end times.
Member Since: Posts: Comments:
Even if that wave off of Africa becomes Invest 93-L, if 92L can't develop before hitting the shear, we can pretty much expect the same fate as this so-called 93L (which it isn't). I mean, this "93L" wave doesn't have as much convective organization as 92L when it emerged from Africa, so it needs more time than 92L had for development.

It still is pretty stunning to see that we have such an impressive pair of tropical wave in the E Atlantic. Tropical cyclones or not, this is a big harbinger of things to come.
Member Since: Posts: Comments:
you ever heard of a cat 6 then thats what we will have
Member Since: Posts: Comments:
1079. Levi32
Quoting louisianaboy444:
Hopefully this is the start of a trend...Waves getting knocked down by wind shear and other variables...The Gulf of Mexico doesn't need a storm this year guys it could be a disaster...I must say i definately like the start of this Hurricane Season 0-0-0 through mid-june...Pray for Shear :)


Nono....this isn't something you think of as a trend for waves getting torn apart. This wave shouldn't even BE as developed as it is...period. It's the opposite of what you are saying. This is the start of a trend for waves to develop. Having them try to pop this early and this far east is insane.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
Quoting MrstormX:


Lol that does no good then, its a shame becasue that land west of Lafayette is nice chasing country. I just hope the wind turbines, and villages are getting hit to hard.


yeah haha definitely dont want to see them get hit
Member Since: Posts: Comments:
BLOG UPDATE!

Hurricane Season Blog #25: 92L Overlook
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1075. KEEPEROFTHEGATE (Mod)
Quoting JDSmith:


Uhm... What does a hurricane do over... 100 Degree water?
BECOME REAL NASTY
Member Since: Posts: Comments:
To clarify my sst / TS prediction here is an illustration of OHC: as we can see values rise sharply around 46W, so basically the system will survive or die based on whether it starts moving west.


Steering map shows due W steering so this isn't impossible.
Member Since: Posts: Comments:
Quoting tornadodude:


I work at 5 :p good ole papa johns lol and I live down in Washington, Indiana during the summer


Lol that does no good then, its a shame becasue that land west of Lafayette is nice chasing country. I just hope the wind turbines, and villages arent getting hit to hard.
Member Since: Posts: Comments:
92L will make history its not going to be a RIP it will survive just watch a see
Member Since: Posts: Comments:
1071. IKE
Quoting JDSmith:


Uhm... What does a hurricane do over... 100 Degree water?


I don't want to find out...lol.
Member Since: Posts: Comments:
1069. IKE
Quoting extreme236:
I guess all we can say is...next?


Yup...until it gets to the western Caribbean or western ATL.


Quoting louisianaboy444:
Hopefully this is the start of a trend...Waves getting knocked down by wind shear and other variables...The Gulf of Mexico doesn't need a storm this year guys it could be a disaster...I must say i definately like the start of this Hurricane Season 0-0-0 through mid-june...Pray for Shear :)


I'll 2nd those thoughts...96 degree water temp? That's insane!
Member Since: Posts: Comments:
Quoting MrstormX:


Do you have work? If you don't I know where I would be driving; just head up Northwestern, pop on 52 and before you know it... twister!


I work at 5 :p good ole papa johns lol and I live down in Washington, Indiana during the summer
Member Since: Posts: Comments:
1067. JDSmith
Quoting IKE:


That's incredible...that's buoy 42040...64NM south of Dauphin Island,AL....

Water Temperature (WTMP): 95.9 °F


Uhm... What does a hurricane do over... 100 Degree water?
Member Since: Posts: Comments:
Afternoon,

Wow, I must eat crow now, I said early this morning that 92L would be a tropical depression by 11 AM. This thing didn't have as defined of a center and I should have considered that, TampaSpin early this morning was right.

Well in the future, I should never trust broad systems as rapid developers ever unless you see a tight center (this is no Claudette 2009 or Humberto 2007). I will be more conservative the next time we have a broad, large system.
Member Since: Posts: Comments:
At least 92L looks healthier then 92E.
Member Since: Posts: Comments:
Hopefully this is the start of a trend...Waves getting knocked down by wind shear and other variables...The Gulf of Mexico doesn't need a storm this year guys it could be a disaster...I must say i definately like the start of this Hurricane Season 0-0-0 through mid-june...Pray for Shear :)
Member Since: Posts: Comments:
I guess all we can say is...next?
Member Since: Posts: Comments:
1062. IKE
Quoting chawk:
What's that spinning in the SW GOM? One thing is for sure, the oil is absorbing heat, check out the bouys in the upper GOM,
Wind Direction (WDIR): N ( 10 deg true )
Wind Speed (WSPD): 1.9 kts
Wind Gust (GST): 3.9 kts
Wave Height (WVHT): 1.0 ft
Dominant Wave Period (DPD): 8 sec
Average Period (APD): 5.5 sec
Mean Wave Direction (MWD): S ( 175 deg true )
Atmospheric Pressure (PRES): 29.98 in
Pressure Tendency (PTDY): -0.04 in ( Falling )
Air Temperature (ATMP): 88.7 °F
Water Temperature (WTMP): 95.9 °F
Dew Point (DEWP): 74.7 °F
Heat Index (HEAT): 98.4 °F
Combined plot of Wind Speed, Gust, and Air Pressure
This is in very deep water!! The other three going towards Tampa are 89 and 90 degrees Water Temp both in several hundred feet.


That's incredible...that's buoy 42040...64NM south of Dauphin Island,AL....

Water Temperature (WTMP): 95.9 °F
Member Since: Posts: Comments:
Quoting tornadodude:


Do you have work? If you don't I know where I would be driving; just head up Northwestern, pop on 52 and before you know it... twister!
Member Since: Posts: Comments:
Quoting Patrap:
2km Storm Relative IR Imagery with BD Enhancement Curve
1915 UTC



Quoting RecordSeason:
I vote Gomex gets a TS before 92L...


why? Do the m odels show something?
Member Since: Posts: Comments:
1059. KEEPEROFTHEGATE (Mod)
Member Since: Posts: Comments:
Quoting IKE:
92L....



Not going to say its R**, but right now its not looking to hot. Its possible its circulation could survive the shear and develop later down the line but given the shear values that would be quite a feat. It needs to do a quick re-fire within the next 12 hours to stand any chance of becoming a TD.

Bear in mind this storm could also be classified as a TD in post season analysis as well.
Member Since: Posts: Comments:
My latest blog entry on 92L,was it a TD for a short time????
Member Since: Posts: Comments:
Member Since: Posts: Comments:
1054. chawk
What's that spinning in the SW GOM? One thing is for sure, the oil is absorbing heat, check out the bouys in the upper GOM,
Wind Direction (WDIR): N ( 10 deg true )
Wind Speed (WSPD): 1.9 kts
Wind Gust (GST): 3.9 kts
Wave Height (WVHT): 1.0 ft
Dominant Wave Period (DPD): 8 sec
Average Period (APD): 5.5 sec
Mean Wave Direction (MWD): S ( 175 deg true )
Atmospheric Pressure (PRES): 29.98 in
Pressure Tendency (PTDY): -0.04 in ( Falling )
Air Temperature (ATMP): 88.7 °F
Water Temperature (WTMP): 95.9 °F
Dew Point (DEWP): 74.7 °F
Heat Index (HEAT): 98.4 °F
Combined plot of Wind Speed, Gust, and Air Pressure
This is in very deep water!! The other three going towards Tampa are 89 and 90 degrees Water Temp both in several hundred feet.
Member Since: Posts: Comments:
1053. IKE
SHIPS model keeps lowering the outlook for 92L. Two days ago it had it nearing a 90mph hurricane....

Member Since: Posts: Comments:
Does this bear watching?

Member Since: Posts: Comments:
1051. KEEPEROFTHEGATE (Mod)
Member Since: Posts: Comments:
nasty looking cell headed towards Purdue

Member Since: Posts: Comments:
the weaker the system the west it goes the stronger the system the more north it goes
Member Since: Posts: Comments:
Tornado Warning in Benton county huh? That can't be good for all the wind turbines there, not to mention the small villages that might not have adequate warning systems.
Member Since: Posts: Comments:
1047. KEEPEROFTHEGATE (Mod)


INV/92/L
MARK
11.3N/41.0W
Member Since: Posts: Comments:
1046. IKE
92L....

Member Since: Posts: Comments:
1045. 900MB
Quoting winter123:
Still intensifying... easterly winds to the south of a well defined COC now. Will easily be TD1 if we get one burst tonight.
Link


Not sure about that, but looks a tad better in last few frames.
Member Since: Posts: Comments:
Quoting MrstormX:


If I may respectfully disagree, the CMC/GEM might over exaggerate but it is still a viable tool for forecasting, especially in non-tropical situations.

yeah ... in winter it's great ... .but not for the tropics.
Member Since: Posts: Comments:
Quoting DestinJeff:


not sure, GEMGLB? whatever that is. same one showed a 996mb L in North Central GOM mid week next week, from a disturbance moving thru southern bahamas.

its out of canada so I think it's the cmc. correct me if Im wrong.
Member Since: Posts: Comments:
Tornado Warning

TORNADO WARNING
INC007-142100-
/O.NEW.KLOT.TO.W.0013.100614T2013Z-100614T2100Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
413 PM EDT MON JUN 14 2010

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A

* TORNADO WARNING FOR...
SOUTHEASTERN BENTON COUNTY...

* UNTIL 500 PM EDT

* AT 411 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS
STORM WAS LOCATED NEAR BOSWELL...OR 5 MILES SOUTHWEST OF
ATKINSON...AND MOVING EAST AT 25 MPH.

* THIS TORNADIC STORM WILL BE NEAR...
OXFORD AND ATKINSON AROUND 420 PM.
TEMPLETON AROUND 425 PM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 4062 8740 4058 8710 4048 8710 4048 8743
4048 8744
TIME...MOT...LOC 2013Z 283DEG 22KT 4051 8731

$$

RATZER







Member Since: Posts: Comments:
Quoting SouthALWX:
Is that the CMC showing that? It seems like the kinda crap it would throw up =P


If I may respectfully disagree, the CMC/GEM might over exaggerate but it is still a viable tool for forecasting, especially in non-tropical situations.
Member Since: Posts: Comments:

Viewing: 1091 - 1041

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron