El Niño Watch issued by NOAA; Western Caribbean development next week?
NOAA's Climate Prediction Center issued an El Niño Watch yesterday, saying "that conditions are favorable for a transition from neutral to El Niño conditions during June - August 2009". The pattern of changes in surface winds, upper-level winds, sea surface temperatures, and deeper water heat content are all consistent with what has been observed during previous developing El Niños. As I discussed in detail in last Friday's post, most of our more advanced El Niño computer models are predicting a weak El Niño event for the coming Atlantic hurricane season. If this indeed occurs, it is likely that Atlantic hurricane activity will be suppressed due to the strong upper-level winds an El Niño usually brings to the tropical Atlantic, creating high wind shear that tears hurricanes apart.
Figure 1. Departure from average of the heat content of the upper 300 meters of the ocean in the Equatorial Eastern Pacific. Much of this increase in heat content is due to a large area of waters 2 - 4°C warmer than average at the thermocline (a depth of 50 - 150 meters). The heat content of the ocean has been steadily increasing since January, consistent with a developing El Niño episode. Image credit: NOAA's Climate Prediciton Center.
Western Caribbean development possible next week
An area of disturbed weather has developed over Central America and the adjacent waters of the Eastern Pacific and Western Caribbean, associated with a tropical wave interacting with the Intertropical Convergence Zone (ITCZ) in the Eastern Pacific. This disturbance has generated 1 - 2 inches of rain over Costa Rica and western Panama over the past day, and is likely to bring 4 - 6 more inches of rain to those areas and Nicaragua over the next 3 - 4 days, as the storm drifts northwards into the Western Caribbean. The subtropical jet stream, which is currently bringing high wind shear to the Caribbean, is expected to shift northwards next week, bringing low wind shear to the region. The last few runs of several of our major dynamical computer weather forecast models have been pointing to the possible development of a tropical depression southwest of Jamaica by Thursday of next week. Heavy rains from the disturbance should spread into Jamaica and Cuba by Thursday and Friday, and may affect the Bahamas, Haiti, and South Florida 7 - 8 days from now.
Figure 2. Visible satellite image of the Central American disturbance expected to cross over into the Western Caribbean next week.
I'll have an update this weekend, probably on Sunday.
Jeff Masters
Reader Comments
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We are not just talking about a 200mb high. This is a deep layered ridge. A cyclone cannot simply move in. There is strong mid level dry air. The stronger the ridge is the more subsidence there will be. Surface high or no surface high.
First of all the GFS has been goofing up on everything regarding that area. The 48-hour 500mb shows the cutoff just before it dissipates over Florida. The 200mb shows it as the trough you describe within the sub-tropical jet, but at the mid-levels it's a mid-level cutoff between the jet branches. It's not the classic trough split but it could be called one. Once the ridge builds into the GOM and the sub-tropical jet lifts out it will be easier for true trough splits to occur.
Not a horse racing fan, but yea; I like that story. Go Calvin
It's not a mid level cut-off until it is surrounded by the isohypse otherwise it's just residue flow.
500mb isn't too deep for a cyclone to form under, and the GFS is not forecasting anomalous surface ridging in the western Gulf of Mexico. A cyclone can't just move into it, but I'm talking about forming UNDER it. This is early-season developments we're talking about here.
And the GFS showed that 3 days ago until it started barfing. The fate of the low over Florida is still uncertain at this point. I don't know if it will become a true trough split but the point is it still could.
I've enjoyed these discussions but I gotta go now to do some work outside while it's still sunny. Later all.
This ridge is 200mb-850mb thick. With that column you are going to have subsidence. The point alone is not just forming under it but the dry mid level conditions which you are not addressing. This is also a synoptic-scale high pressure system fairly large in nature. The high is the reason for the system's asymmetric appearance on the GFS.
And the forecast can't solely be based on what the GFS says which is the majority of your backing. The UKMET, NOGAPS, and CMC still exist as models.
I can already see the blog going into self destruct mode.
LOL. WeatherStudent putting up shutters.
With all due respect but I can see this happening too....
Taco :0)
God I hope not. Sits over South Florida for 2 days, I would need a canoe.
The blog couldn't survive.....@ 204 hrs....
Heck i thought you had an "Ark"
LMAO
Taco :0)
Pouring a shot of Vodka.
I don't know if a canoe would do it, probably would need an ark.
You'd need a cruise ship.
I Love That Drakoen .... LOL
Taco:0)
Yup...again.
I was thinking more like The gulf of Mexico
Taco :0)
Yup.
Well we already lost South Beach..
Also, whoever decided light blue on white was a good idea is insane.
http://tinyurl.com/r4cg9o
I think its still cold core though.
Taco :0)
LOL. Yup, it would implode!
I'd be shocked if it wasn't still yellow... They're expecting it to be quite slow to develop.
I agree. This is early June anyway. I wouldn't expect too much, although I know anything is possible.
Thats good. That must be a new rule since when I joined in 06 I could post right away.
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