5:30PM EDT Update 28 Jun 2009
Although there are a few things to watch in the tropics, the set up this week seems to prevent any tropical development.

93L has nothing more going for it than a wave axis at the moment, and looks like it won't do much other than cause some rain (even that won't be all that much). The satellite presentation, surrounding conditions, and an oncoming front arriving around Tuesday should finish whatever is left off.

10:40PM EDT Update 27 Jun 2009
The Wave known as 93L has not persisted much today, models are no longer predicting development, and neither are we. We'll watch what remains, but it's real chance has come and gone. Satellite indicates northerly shear may be starting to form in the Gulf, which will further diminish any chance of development.



Elsewhere in the tropics, thankfully, there isn't much to watch. Things can change, but until then enjoy the Independence Day week (In the USA)!

7:00AM EDT Update 27 Jun 2009

The wave (93L) in the western Caribbean Sea has decreased in convection overnight, which lowers the chances for development soon, there is still enough organization to keep it worth watching. Most of the model runs have lowered its projected intensity for it in the Gulf, which is good news.



There is still a 50-70% chance this system will not develop, and until a low level circulation has formed, it will not. Signs of it are showing just off the eastern coast of the Yucatan. But in general, the system is not looking all that great. It likely will not develop today,.

If the general system persists until reaching the Gulf (it may just clip or pass to the east of the Yucatan) it has a chance to develop then. But for today, it looks like it won't reach tropical status.

If a circulation center doesn't form by sometime in the Gulf it will just mean rain for Florida.

Those in the Eastern Gulf should continue to monitor this into next week.

6:15PM EDT Update 26 Jun 2009

93L is maintaining itself well, and the chance of development remains around 30-50%. More model runs are coming out which indicates the eastern Gulf of Mexcio will be most likely affected by whatever happens around Tuesday or Wednesday. As it is not completely developed, things may change.

If it persists through the evening into tomorrow, and a true low level circulation forms, then it's open to become a named storm.



The movement may depend on how rapidly the ridge to the northwest of the system develops vs the trough to the northeast of the system. If the ridge prevails,.the system should move more to the northwest, however, if the trough prevails the system should eventually move more northeast. Currently the low level tropical model suite moves the system to the northwest whereas the deeper models (HWRF, GFS) that incorporate the upper level flow eventually move the system to the northeast.

2PM EDT Update 26 Jun 2009
The wave in the west Caribbean (93L) has organized a bit this morning, more around the center than previously. It looks like it will not develop enough in time to be named before it reaches the Yucatan, but it will likely be on the upswing when it does.

What is more interesting is what happens after it moves near or across the tip of the Yucatan, most likely into the Southern Gulf. If it survives that, Once there, chances improve quite a bit that this system will develop, meaning those along the Gulf Coast will want to watch this one. Some longer range models indicate the eastern Gulf will want to keep watch on it.

More updates to come...

What do you think it will do? Let us know in the 93L Lounge.

Original Update
There is a tropical wave in the Western Caribbean that is running roughly from the Cayman Islands toward Honduras, moving generally west. Conditions around the system are slightly on the favorable side, so it has a bit of a chance to develop. It only has until overnight tonight to develop, however, as by then it will have reached the Yucatan Peninsula.

It has about a 20-30% shot, but its looking rather well this morning. As of 8AM, it is being tracked as an official Invest, designated 93L. This is worth watching to see if it develops today, as this area is a prime area for Development in late June.

The National Hurricane center in their Outlook is focusing on the wave (surface low), rather than the Mid Level Circulation, at the moment, but both may work their way together. Currently the convection (to the northeast) is away from the center (which is further to the south and west) and may be dispersing. This helps to keep the system from developing at all, which is the most likely outcome. If it survives the Yucatan, it will be worth watching then as it may be near the western or central Gulf of Mexico.



More to come....

93L Event Related Links

Animated Skeetobite Model Plot of 93L
SFWMD Model Plot (Animated Model Plot) SFWMD Hurricane Page (More Tracking Information)
Clark Evans Track Model Plot of 93L (Animated!)
Clark Evans Intensity Model Plot of 93L (Animated!)
More model runs on from Jonathan Vigh's page
NRL Info on 93L -- RAMMB Info

Floater Satellite Images: Visible (Loop), IR [Loop), WV (Loop), Dvorak (Loop), AVN (Loop), RGB (Loop), Rainbow (Loop)

Updated - 06/30/09
Based on seasonal SST values before a significant El Nino event, 1965 and 1986 are now the best analog years for this seasons expected tropical cyclone activity in the Atlantic basin. Although many factors contribute to a seasonal forecast, historical SST data suggest that 2010 (next year) will see a return to a more normal season of activity in the Atlantic basin (see totals for 1958, 1970, 1973, 1988, 1995, 1998, 2005 and 2007). Exceptions were 1983, 1987 and 1992. It is worth noting that significant El Nino events rarely last more than a year, whereas La Nina events often last two or three years.

Original Article
There is now a high probability that a moderate to strong El Nino event will be in place in the Pacific ENSO regions for this hurricane season. The latest 6-Month SST Forecasts continue to trend toward a healthy El Nino event.

First, a look back at some analysis that was posted in 2007:

"Definitions / Number of Events / Percentage:
ENSO Neutral: SST anomaly from -0.5 to +0.5 (33 seasons since 1950) 58%
Moderate El Nino: +0.6 to +0.9 (10 seasons) 18%
Strong El Nino: +1.0 or greater (2 seasons) 3%
Moderate La Nina: -0.6 to -0.9 (8 seasons) 14%
Strong La Nina: -1.0 or greater (4 seasons) 7%
Low activity: 8 named storms or less (20 seasons) 35%
Normal activity: 9 to 13 named storms (27 seasons) 47%
High activity: 14 named storms or more (10 seasons) 18%

The Region 3.4 SST pre-season aggregate average anomaly period: May/June/July. The strongest El Nino pre-season average anomaly for this period was +1.4 in 1997. The strongest La Nina pre-season average anomaly for this period was -1.2 in 1950 and 1988.

Neutral pre-season anomaly vs season totals:
7 low activity seasons / 21% of all Neutral seasons
17 normal activity seasons / 52%
9 high activity seasons / 27%

Moderate pre-season El Nino vs season totals:
9 low activity seasons / 90%
1 normal activity season / 10%
no high activity seasons

Strong pre-season El Nino vs season totals:
2 low activity seasons / 100%
no normal or high activity seasons

Moderate pre-season La Nina vs season totals:
2 low activity seasons / 25%
5 normal activity seasons / 63%
1 high activity season / 12%

Strong pre-season La Nina vs season totals:
no low activity seasons
4 normal activity seasons / 100%
no high activity seasons

When the M/J/J average SST anomaly is +0.6 or greater, 92% of the time the season storm total will be 8 named storms or less. When that average is -0.6 or greater, 92% of the time the season storm total will be 13 named storms or less (and 75% of the time the season storm total will be 9 to 13 named storms, i.e., a normal season. Note that a normal season, because of the increased activity since 1995, is now 11 named storms). A strong pre-season La Nina has never resulted in a high activity storm season. Ninety percent of high activity seasons occur under ENSO neutral pre-season conditions."

The M/J/J SST anomaly for this year will probably be in the +0.7 to +1.1 range - and if this should materialize, a lot of high pre-season storm total predictions are in trouble. With the Atlantic basin likely to remain cooler than normal, the expectation for a below normal season is greater than 90%. Current and anticipated ENSO conditions for a moderate to strong early season El Nino suggest that the best analog years for this season are 1957, 1965, 1982 and 1997 (in no particular order). A prediction of 7/3/1 might be a lot closer to the final total for this season.
Cheers,
ED