First tropical depression of the season may form from 92L
An unusually large and well-developed African tropical wave for so early in the season has developed midway between the coast of Africa and South America. The storm was designated Invest 92L by the National Hurricane Center yesterday, and has a good chance of becoming the first tropical depression of the Atlantic hurricane season. Surface winds measured by the 8:23am EDT pass of the European ASCAT satellite revealed that 92L already has a closed surface circulation, though the circulation is large and elongated. Top winds seen by ASCAT were about 25 mph. METEOSAT visible satellite loops show a large and impressive circulation that is steadily consolidating, with spiral bands building inward towards center, and upper-level outflow beginning to be established to the northwest and north.
Figure 1. Morning satellite image of Invest 92L.
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 - 30°C, which is warmer than the temperatures reached during the peak of hurricane season last year, in August - September. 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.) While 92L will cross over a 1°C cooler patch of water on Monday, the storm will encounter very warm SSTs of 28-29°C again by Tuesday.
The disturbance doesn't have to worry about dry air--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 300 - 400 miles from any substantial areas of dry air. The 60-day cycle of enhanced thunderstorm activity called the Madden-Jullian 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.
The forecast for 92L
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 is currently located at 7°N, well south of this band of high shear, and is only experiencing 5 - 15 knots of shear. This moderate amount of shear should allow for some steady development of 92L over the next few days as it tracks west-northwest at 10 - 15 mph. The National Hurricane Center is giving 92L a medium (30% chance) of developing into a tropical depression by Tuesday morning. Based on visible satellite imagery over the past few hours, I believe this forecast is not aggressive enough, and that 92L has a 50% chance of developing into a tropical depression by Tuesday morning. Another factor holding 92L back is its proximity to the Equator. I would give 92L higher chances of developing if it were not so close to the Equator. The system is organizing at about 7°N latitude, which is so close to the Equator that it cannot leverage the Earth's spin much to help it get spinning. It is quite unusual for a tropical depression to form south of 8°N latitude.
The farther south 92L stays, the better chance it has at survival. With the system's steady west-northwest movement this week, 92L should begin encountering hostile wind shear in excess of 30 knots by Thursday, which should be able to greatly weaken or entirely destroy the storm before it gets to the Lesser Antilles Islands. However, 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 by Saturday or Sunday next weekend. The GFDL and HWRF models are predicting that 92L will develop into a moderate strength tropical storm that will then be weakened or destroyed by the end of the week, before it reaches the islands. This looks like a reasonable forecast.
Figure 3. The departure of sea surface temperature (SST) from average for June 10, 2010. Image credit: NOAA/NESDIS.
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
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This is the wave I am worried about.
You have learnt much grasshopper... well done
Thanks alot, My last 2 years are mostly Major courses so i'm getting into the niddy griddy of my major..bring on the all nighters!
Im not sure that makes a whole heap of sense...
It's late and I could be wrong but ... 0.o
It's looking good, we'll see 24 hours from now
Try this, its easier :)
WTNT21 KNGU 140600
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
125 NM EITHER SIDE OF A LINE FROM 8.8N 39.0W TO 10.8N 44.1W WITHIN
THE NEXT 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF
NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
2. A LOW PRESSURE CENTER LOCATED NEAR 08.2N AND 38.5W IS CURRENTLY
MOVING WEST-NORTHWESTWARD AT APPROXIMATELY 10 TO 15 KNOTS.
AT 14/0000Z INFRARED SATELLITE IMAGERY INDICATED AN AREA OF
CONVECTION THAT HAS CONTINUED TO BECOME BETTER ORGANIZED WITHIN THE
PAST 12 HOURS. THIS SYSTEM IS CURRENTLY EXPERIENCING LOW WIND SHEER,
UPPER LEVEL ANTICYCLONIC OUTFLOW AND IS TRACKING TOWARDS WARMER SEA
SURFACE TEMPERATURES OF 82 TO 85 DEGREES FAHRENHEIT, HELPING TO
ENHANCE THE DEVELOPMENT OF THIS TROPICAL FEATURE. SHOULD THIS SYSTEM
DEVELOP INTO A TROPICAL CYCLONE OVER THE NEXT 24 TO 36 HOURS, IT IS
LATER ANTICIPATED TO BEGIN TO TRACK TOWARDS AN ENVIRONMENT LESS
CONDUCIVE TO TROPICAL CYCLONE DEVELOPMENT BY THE MIDDLE OF THE WEEK.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED
BY 150600Z.//
so we finally got it lol
Lightning stroke positions are shown as coloured dots which "cool down" from blue for the most recent (occurring within the last 10 min) through green and yellow to red for the oldest (30-40 minutes earlier).
Red asterisks in white circles are active WWLL lightning sensor locations. The terminator (day-night boundary) is shown, with the daylit section of the globe in grey.
It would. Outflow creates shear. Thus, a close proximity of several tropical cyclones would tend to create shear.
Isnt it funny that when everyone thinks that 92L is in the ''poofing'' process we get this?
XD
I haven't seen you in years. Another big gun. :)
It is so predictable, I really think those that change their thoughts on a system based on every flare up or waning of convection are going to drive themselves nuts and probably should not spend too much time watching these systems develop
I went from OMG Pinhole eye! to lets wait and see. LOL!
And I'm still in that wagon XD
Apparently the NHC thinks the latter.
ALERT ATCF MIL 92X XXX 100614000000
2010061400
8.8 321.0
10.8 315.9
125
8.4 322.4
140600
1006140530
1
SUBJ/TROPICAL CYCLONE FORMATION ALERT 140530Z JUN 10//
WTNT21 KNGU 140600
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
125 NM EITHER SIDE OF A LINE FROM 8.8N 39.0W TO 10.8N 44.1W WITHIN
THE NEXT 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF
NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
2. A LOW PRESSURE CENTER LOCATED NEAR 08.2N AND 38.5W IS CURRENTLY
MOVING WEST-NORTHWESTWARD AT APPROXIMATELY 10 TO 15 KNOTS.
AT 14/0000Z INFRARED SATELLITE IMAGERY INDICATED AN AREA OF
CONVECTION THAT HAS CONTINUED TO BECOME BETTER ORGANIZED WITHIN THE
PAST 12 HOURS. THIS SYSTEM IS CURRENTLY EXPERIENCING LOW WIND SHEER,
UPPER LEVEL ANTICYCLONIC OUTFLOW AND IS TRACKING TOWARDS WARMER SEA
SURFACE TEMPERATURES OF 82 TO 85 DEGREES FAHRENHEIT, HELPING TO
ENHANCE THE DEVELOPMENT OF THIS TROPICAL FEATURE. SHOULD THIS SYSTEM
DEVELOP INTO A TROPICAL CYCLONE OVER THE NEXT 24 TO 36 HOURS, IT IS
LATER ANTICIPATED TO BEGIN TO TRACK TOWARDS AN ENVIRONMENT LESS
CONDUCIVE TO TROPICAL CYCLONE DEVELOPMENT BY THE MIDDLE OF THE WEEK.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED
BY 150600Z.//9210061118 60N 275W 20
9210061200 61N 284W 20
9210061206 61N 293W 20
9210061212 62N 301W 20
9210061218 63N 310W 25
9210061300 64N 321W 20
9210061306 67N 335W 25
9210061312 71N 349W 25
9210061318 78N 363W 25
9210061400 84N 376W 25
lol
Yes, it is. I am personally not poofing 92L. I just think it will have a hard time surviving in the future.
If you have several storms close by, the outflow from one storm could shear another.
yeap there it is
I think we are all guilty of it from time to time, but some make it so obvious that the hinge on every frame lol
Took the words right out of my mouth/fingers...
hmmmmm
Pumpkin chocolate chip - pumpkin = chocolate chip
ok so you have chocolate chip muffins then, can I have one? lol
yeah it has a rough future and big hopes XD
All I need to be convinced is a little flare up of convection, it just seems it fires little cells and they dissipate at the moment
16 degrees wide by longitude ZOMG...this is a true WPac-style storm.
Viewing: 2951 - 3001
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