Dr. Jeff Masters' WunderBlog

First tropical depression of the season may form from 92L
Posted by: Dr. Jeff Masters, 3:38 PM GMT op 13 juni 2010 +2
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
Categories: Hurricane
  Permalink | A A A
Reader Comments
Display: 0, 50, 100, 200 Sort: Newest First - Order Posted
Viewing: 1201 - 1251

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 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78Blog Index

1201. hurricanejunky 8:13 PM GMT op 13 juni 2010    
Forgive me if this has already been asked and answered but is 92L going thru DMIN right now? Looks organized but convection is not as intense.
Member Since: 28 augustus 2006 Posts: 6 Comments: 2877
1202. CaneWarning 8:13 PM GMT op 13 juni 2010    
Quoting TCHP:
I apologies then, at least im a gentlemen enough to know when to realize my falws, UNLIKE OTEHRS. in the emantime, some plz flag the NHC counterfiter, geeze, how do these people get in here.


The same way you keep coming back in here.
Member Since: 26 april 2009 Posts: 3 Comments: 3667
1203. Hurricanes101 8:13 PM GMT op 13 juni 2010    
Quoting FLWeatherFreak91:
Whoever posts any blatantly incorrect, or illegitimate information should be banned from the blog permanently in my opinion. Misinformation is dangerous, especially when so many use this blog as a main source of tropical information. We don't need any deceivers on here... especially if a storm is near land. Hopefully lots of you flagged those posts and administration will take care of it.


It wasnt incorrect or fake, he just failed to note where it came from
Member Since: 10 maart 2010 Posts: 1 Comments: 6930
1204. MrstormX 8:13 PM GMT op 13 juni 2010    
Quoting Hurricanes101:


it became 50% at 2pm which is the high end for orange


Next comes Red.
Member Since: 27 mei 2009 Posts: 0 Comments: 4312
1205. xcool 8:14 PM GMT op 13 juni 2010    
convection blows up popop
Member Since: 26 september 2009 Posts: 2 Comments: 15526
1207. Tazmanian 8:14 PM GMT op 13 juni 2010    
Quoting FLWeatherFreak91:
Whoever posts any blatantly incorrect, or illegitimate information should be banned from the blog permanently in my opinion. Misinformation is dangerous, especially when so many use this blog as a main source of tropical information. We don't need any deceivers on here... especially if a storm is near land. Hopefully lots of you flagged those posts and administration will take care of it.





i no i did not find that too funny
Member Since: 21 mei 2006 Posts: 5089 Comments: 111632
1208. NOVArules 8:14 PM GMT op 13 juni 2010    
I hope 92L does not turn into this in the future...


Member Since: 26 augustus 2009 Posts: 0 Comments: 178
1209. xcool 8:14 PM GMT op 13 juni 2010    
lol pot
Member Since: 26 september 2009 Posts: 2 Comments: 15526
1210. CyclonicVoyage 8:14 PM GMT op 13 juni 2010    
TPC not thinking too much of 92L right now.

13/1745 UTC 6.7N 36.1W T1.0/1.0 92L -- Atlantic
Member Since: 30 januari 2010 Posts: 0 Comments: 3259
1211. MiamiHurricanes09 8:14 PM GMT op 13 juni 2010    
Cariboy my sincerest apologies, what he posted is from the Puerto Rico NWS:

BROAD AREA OF LOW PRES ACROSS THE CNTRL ATLC ALONG 37W IS BECOMING
BETTER ORGANIZED AND APPEARS THIS SYSTEM HAS A VERY GOOD CHANCE IN
BECOMING THE FIRST NAMED STORM OF THE 2010 HURRICANE SEASON. THIS
SYSTEM IS EXPECTED TO TRACK WNW OVR THE NEXT SVRL DAYS WITH MODEL
GUIDANCE INDICATING THIS SYSTEM ENCOUNTERING STRONG SHEAR AS IT
APPROACHES THE WINDWARD ISLANDS LATER IN THE WEEK. 12Z ECMWF AND
CANADIAN GLOBAL MODELS SEEM TO HAVE THE BEST HANDLE ON THIS
DEVELOPING CYCLONE AND BRING THE SYSTEM CLOSE TO THE REGION SAT BUT
AS AN OPEN WAVE. MAIN EFFECT FROM THIS SYSTEM LOOKS TO BE TORRENTIAL
RAINFALL. SO RIGHT NOW IT LOOKS LIKE NEXT WEEKEND COULD BE WET BUT
THIS IS HIGHLY DEPENDENT ON THE TRACK OF THE STORM WHICH HAS YET
TO FORM. GIVEN GOOD TRACK RECORD OF EUROPEAN MODEL WITH TROPICAL
CYCLONES OVER THE LAST FEW YEARS IT APPEARS WILL SEE INCREASING
CHANCES FOR WIDESPREAD RAINFALL NEXT WEEKEND. REGARDLESS OF
WHETHER THIS STORM FORMS OR NOT...BOTTOMLINE IS THAT CONDITIONS IN
THE TROP ATLC ARE ALREADY FAVORABLE FOR TROPICAL CYCLONE FORMATION
AND PEOPLE SHOULD GO OVER THEIR EMERGENCY PLANS AND BE READY FOR
THE NEXT TROPICAL CYCLONE THREAT NO MATTER WHEN IT MIGHT COMING
KNOCKING ON THE DOOR.

Link

Member Since: 2 september 2009 Posts: 129 Comments: 20011
1212. ImASaladTosser 8:15 PM GMT op 13 juni 2010    
What does Dmin mean?
1214. Tazmanian 8:15 PM GMT op 13 juni 2010    
Quoting NOVArules:
I hope 92L does not turn into this in the future...





fredy boy am home
Member Since: 21 mei 2006 Posts: 5089 Comments: 111632
1215. CaribBoy 8:15 PM GMT op 13 juni 2010    
Quoting CaribBoy:


That's not a fake : PR DISCUSSION


And it made me laughing! OPEN WAVE!
Member Since: 6 oktober 2007 Posts: 0 Comments: 2982
1216. MiamiHurricanes09 8:15 PM GMT op 13 juni 2010    
Quoting CaribBoy:


That's not a fake : PR DISCUSSION
Yeah, I saw it, I'm very sorry about it.
Member Since: 2 september 2009 Posts: 129 Comments: 20011
1217. FLWeatherFreak91 8:15 PM GMT op 13 juni 2010    
Quoting MiamiHurricanes09:
What's wrong with the blog?? Enough of the fake stuff. No actually proceed, I'm having a good laugh over this.
That post isn't fake. It's the afd out of San Juan.
Member Since: 1 december 2006 Posts: 2 Comments: 3516
1218. Tazmanian 8:16 PM GMT op 13 juni 2010    
Quoting MiamiHurricanes09:
Cariboy my sincerest apologies, what he posted is from the Puerto Rico NWS:

BROAD AREA OF LOW PRES ACROSS THE CNTRL ATLC ALONG 37W IS BECOMING
BETTER ORGANIZED AND APPEARS THIS SYSTEM HAS A VERY GOOD CHANCE IN
BECOMING THE FIRST NAMED STORM OF THE 2010 HURRICANE SEASON. THIS
SYSTEM IS EXPECTED TO TRACK WNW OVR THE NEXT SVRL DAYS WITH MODEL
GUIDANCE INDICATING THIS SYSTEM ENCOUNTERING STRONG SHEAR AS IT
APPROACHES THE WINDWARD ISLANDS LATER IN THE WEEK. 12Z ECMWF AND
CANADIAN GLOBAL MODELS SEEM TO HAVE THE BEST HANDLE ON THIS
DEVELOPING CYCLONE AND BRING THE SYSTEM CLOSE TO THE REGION SAT BUT
AS AN OPEN WAVE. MAIN EFFECT FROM THIS SYSTEM LOOKS TO BE TORRENTIAL
RAINFALL. SO RIGHT NOW IT LOOKS LIKE NEXT WEEKEND COULD BE WET BUT
THIS IS HIGHLY DEPENDENT ON THE TRACK OF THE STORM WHICH HAS YET
TO FORM. GIVEN GOOD TRACK RECORD OF EUROPEAN MODEL WITH TROPICAL
CYCLONES OVER THE LAST FEW YEARS IT APPEARS WILL SEE INCREASING
CHANCES FOR WIDESPREAD RAINFALL NEXT WEEKEND. REGARDLESS OF
WHETHER THIS STORM FORMS OR NOT...BOTTOMLINE IS THAT CONDITIONS IN
THE TROP ATLC ARE ALREADY FAVORABLE FOR TROPICAL CYCLONE FORMATION
AND PEOPLE SHOULD GO OVER THEIR EMERGENCY PLANS AND BE READY FOR
THE NEXT TROPICAL CYCLONE THREAT NO MATTER WHEN IT MIGHT COMING
KNOCKING ON THE DOOR.

Link






how many more times dos that need too be posted
Member Since: 21 mei 2006 Posts: 5089 Comments: 111632
1219. CaribBoy 8:16 PM GMT op 13 juni 2010    
Quoting MiamiHurricanes09:
Yeah, I saw it, I'm very sorry about it.


It's ok dont worry :)
Member Since: 6 oktober 2007 Posts: 0 Comments: 2982
1220. aspectre 8:16 PM GMT op 13 juni 2010    
859 Weather456 "Why isn't the NHC issuing TS watches and warnings for Guyana, Suriname and French Guiana"

As far as I'm aware, none of the three have ever been hit by a TropicalCyclone...
...not that this couldn't be a year for firsts...
...but they certainly promote themselves as being in the hurricane-free zone.
Member Since: 21 augustus 2007 Posts: 0 Comments: 4855
1221. MiamiHurricanes09 8:16 PM GMT op 13 juni 2010    
Quoting FLWeatherFreak91:
That post isn't fake. It's the afd out of San Juan.
I know, I posted it already saying sorry. It just looked fake in matter.
Member Since: 2 september 2009 Posts: 129 Comments: 20011
1223. cg2916 8:16 PM GMT op 13 juni 2010    
Quoting FLWeatherFreak91:
Whoever posts any blatantly incorrect, or illegitimate information should be banned from the blog permanently in my opinion. Misinformation is dangerous, especially when so many use this blog as a main source of tropical information. We don't need any deceivers on here... especially if a storm is near land. Hopefully lots of you flagged those posts and administration will take care of it.


I didn't mean it.
Member Since: 21 december 2007 Posts: 13 Comments: 2955
1224. MiamiHurricanes09 8:17 PM GMT op 13 juni 2010    
Quoting Tazmanian:





how many more times dos that need too be posted
6 maybe? LOL!
Member Since: 2 september 2009 Posts: 129 Comments: 20011
1225. PanhandleChuck 8:17 PM GMT op 13 juni 2010    
This blog has totally turned into Romper Room. Only those of us who are of age will know what that is. Some people in here need to understand that when they post so many times, they are going to "Clog the Blog"
Member Since: 13 mei 2008 Posts: 0 Comments: 1189
1226. xcool 8:17 PM GMT op 13 juni 2010    
Member Since: 26 september 2009 Posts: 2 Comments: 15526
1227. FLWeatherFreak91 8:18 PM GMT op 13 juni 2010    
Looks like 92l is developing more convection wrapped tightly around the center. We should see a nice burst or "ball" of convection form overnight. It's then that the NHC will likely upgrade to TD 1. As I said earlier, they will probably quickly go from TD 1 to Alex sometime tomorrow.
Member Since: 1 december 2006 Posts: 2 Comments: 3516
1228. cg2916 8:18 PM GMT op 13 juni 2010    
Quoting NOVArules:
I hope 92L does not turn into this in the future...




Wilma! LMAO
Member Since: 21 december 2007 Posts: 13 Comments: 2955
1231. SLU 8:18 PM GMT op 13 juni 2010    
Quoting cg2916:
This is fake. We do NOT, I repeat, NOT have TD1.


This is a bannable offense. Whats the point?
Member Since: 13 juli 2006 Posts: 11 Comments: 3055
1232. JRRP 8:18 PM GMT op 13 juni 2010    

see you later
Link
Member Since: 16 augustus 2007 Posts: 0 Comments: 4358
1233. CaneWarning 8:19 PM GMT op 13 juni 2010    
Quoting PanhandleChuck:
This blog has totally turned into Romper Room. Only those of us who are of age will know what that is. Some people in here need to uderstand that when they post so many times, they are going to "Clog the Blog"


The blog is clogged already. I can't imagine how crazy it will be when a storm threatens land. Thank goodness for the ignore feature.
Member Since: 26 april 2009 Posts: 3 Comments: 3667
1237. xcool 8:19 PM GMT op 13 juni 2010    
Acemmett90 .no.
Member Since: 26 september 2009 Posts: 2 Comments: 15526
1238. Chicklit 8:19 PM GMT op 13 juni 2010    

ginormous.
Member Since: 11 juli 2006 Posts: 14 Comments: 10382
1239. MiamiHurricanes09 8:19 PM GMT op 13 juni 2010    
Still like the BAMM model...

Member Since: 2 september 2009 Posts: 129 Comments: 20011
1240. MrstormX 8:20 PM GMT op 13 juni 2010    
Quoting SLU:


This is a bannable offense. Whats the point?


No if you read the initial post it was misunderstood, not fake but some people have yet to read his original post.
Member Since: 27 mei 2009 Posts: 0 Comments: 4312
1242. xcool 8:21 PM GMT op 13 juni 2010    
BAMM BEST HANDLE ON THIS IMO...
Member Since: 26 september 2009 Posts: 2 Comments: 15526
1244. BahaHurican 8:21 PM GMT op 13 juni 2010    
Quoting pottery:

I have been waiting on someone to raise this possible scenario.
The thing is organising slowly, and is in no hurry to go north as far as I can see.
The track models are moving too far north, too quickly....
Would be interesting if Trinidad got its first "strike" in ages from a mid-June TC....
Member Since: 25 oktober 2005 Posts: 19 Comments: 17961
1245. cg2916 8:21 PM GMT op 13 juni 2010    
Quoting SLU:


This is a bannable offense. Whats the point?


I was saying, I think that this isn't too far away.
Member Since: 21 december 2007 Posts: 13 Comments: 2955
1246. Hurricanes101 8:21 PM GMT op 13 juni 2010    
*sits back with soda and popcorn*
Member Since: 10 maart 2010 Posts: 1 Comments: 6930
1247. xcool 8:21 PM GMT op 13 juni 2010    
Acemmett90 OH ;)
Member Since: 26 september 2009 Posts: 2 Comments: 15526
1248. PanhandleChuck 8:22 PM GMT op 13 juni 2010    
Quoting CaneWarning:


The blog is clogged already. I can't imagine how crazy it will be when a storm threatens land. Thank goodness for the ignore feature.


Yup... Trolls will be rolling in here like bowling balls in an alley. This is just the tip of the iceberg and it's a shame that it seems as though many of the more respected bloggers are not posting. Probably due to all of the nonsense going on in here and the doomcasters
Member Since: 13 mei 2008 Posts: 0 Comments: 1189
1249. Chicklit 8:22 PM GMT op 13 juni 2010    

Member Since: 11 juli 2006 Posts: 14 Comments: 10382

Viewing: 1201 - 1251

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 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78Blog Index

New Comment
Community Standards Policy Comments will take a few seconds to appear.
Post Your Comments
Please sign in to post comments.
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.
About JeffMasters
Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Community Activity