2013 Steering Pattern / Early indicators

[chaser1]

Does anyone else out there see what I am seeing?? Or have I just been watching too many pods of Mullet swimming in counter-clockwise circles lately, LOL??

I am just not sure why, but something about the particularly strong 200mb wind flow just seem "off". I think more than anything, I just don't seem to recollect any recent past Spring seasons as having these winds so consistently spanning what seems like the entire Gulf region, across the Greater Antilles and Caribbean, and practically continuing almost all the way to Africa. Even during prior El Nino years we would see quite strong Westerlies, but strong as this upper shear seemed to be, those winds would moderate in intensity as that flow started exiting the Caribbean. I believe in those years with "El Nino" originating Westerlies, those winds would eventually interact with either an East Coast trough/TUTT condition, or maybe an oscillating mid-Atlantic trough that seemed persistently anchored in the W. Central Atlantic. Either way, even under those hostile upper air circumstances there would seem to be some downstream difluent conditions where those Westerlies eventually were shunted more pole-ward and an outflow channel would be created (if an active tropical wave were in the area to take advantage).

I very well realize that this is early May, but it just seems odd to me that the present upper level winds seem almost trapped within the sub-tropics latitudes and at present have nowhere else to go but as "East as far as the eye can see". More than likely this deviant flow will just give way to the eventual Easterly surge of ridging that would typically build Westward over the summer. Anyway you look at it though, I just cant see anything near term other than hostile wind shear conditions. These persistent upper air conditions do not look to change anytime in the foreseeable future. So if that were the case, it just wouldn't seem to matter what "alphabet soup" might be projected to surge in "our side of the bowl". These hostile conditions would seem to disrupt tropical genesis from occurring. While a late May or early June depression or even weak storm could well occur, I would bet against it at least until it was evident that some low latitude ridging was occurring somewhere.

[SouthDadeFish]

Chaser1,

Here is the current wind shear anomaly over the Tropical Atlantic Ocean:



Just what I would expect to see for May. Some areas above average (reds) and some below average (blues). Often times there are very strong westerlies still active in May, especially early May.

[tolakram]

The Countdown Is On! My thoughts on the rest of May, and a bit of news: http://jonathanbelles.wordpress.com/201 ... own-is-on/

Tomorrow, I will begin my summer internship with the NOAA Hurricane Hunters.

Oh really?

[artist]

The Countdown Is On! My thoughts on the rest of May, and a bit of news: http://jonathanbelles.wordpress.com/201 ... own-is-on/

Awesome news and congrats Jonathan!

[cycloneye]

Here is the latest MJO forecast until May 22nd and it continues to be a strong pulse that will reach the EPAC and Caribbean by late May going thru early June.

[chaser1]

Chaser1,

Here is the current wind shear anomaly over the Tropical Atlantic Ocean:



Just what I would expect to see for May. Some areas above average (reds) and some below average (blues). Often times there are very strong westerlies still active in May, especially early May.

Mike, thanks for the anomaly map. Actually, kinda confirms my thoughts on the upper levels. No doubt the season has not even started. Of course one assumes that most years will show some anomalies for measured conditions (either high or low), but considering the length of time that such upper level winds have rather consistently continued nearly all the way across the Atlantic, and the (red) anomalies bear this out. I cannot help but think that the upper level flow is indicative of something more occurring, and am starting to wonder if this might only be "transient" or perhaps indicative of longer term hostile upper air throughout a large portion of the Atlantic sub tropical latitudes.

Well, not much to do but sit and watch anyway. Will be interesting to see if/when the longer range EURO or GFS start to either expand the North Atlantic ridge southward, or perhaps start seeing some upper air ridging from Africa expanding westward. Wonder if such a present feature might evolve to be something akin to a misplaced (east/west) TUTT feature throughout the season?

[SFLcane]

i wouldn't worry to much chaser1 its may. Models show a relaxation of the 200mb winds in the coming days.

[SFLcane]

Crownweather http://www.crownweather.com/?p=7351

Each and every morning I take a look at the overall setup across the Atlantic and notice different things that I make mental notes of. Here are some additional thoughts on the upcoming season which officially starts in just 27 days.

The more I look at things the more I believe that this year will be very much different than the Hurricane seasons of 2012 and 2011. First, the atmosphere across the Atlantic is expected to be more unstable than what was seen in 2011 and 2012. Additionally, the Caribbean has the possibility of seeing average or even slightly above average unstable conditions. What does this mean? An unstable atmosphere promotes thunderstorms and large areas of disturbed weather which in many cases leads to the development of tropical storms and hurricanes.

It seems plausible this year that we will see more intense convection along the Inter-Tropical Convergence Zone, something that was not seen last year. In fact, this seems to already be occurring, especially across the African continent.

A positive TNA signal and a strong position AMO is likely to not only promote tropical storm and hurricane development this season, it is also likely to favor a high pressure ridge very near the southeastern United States. Also a negative NAO which is present should lead to a high landfall risk across much of the southeastern United States and the eastern & central Gulf states centered right on the Florida Peninsula. Additionally, there is the possibility of southeast Florida being impacted by a major hurricane this season. In closing, it seems very possible that we will see an active year in terms of landfalling tropical storms and hurricanes with a emphasis on the Florida Peninsula. This hurricane season seems poised to be very much different than what we saw in 2011 and 2012.

[cycloneye]

CFSv2 and NMME anomalies forecast for August,September and October calls for warm waters in the MDR and Caribbean.

CFSv2



NMME



http://www.cpc.ncep.noaa.gov/products/NMME/

[Bocadude85]

Crownweather http://www.crownweather.com/?p=7351

Each and every morning I take a look at the overall setup across the Atlantic and notice different things that I make mental notes of. Here are some additional thoughts on the upcoming season which officially starts in just 27 days.

The more I look at things the more I believe that this year will be very much different than the Hurricane seasons of 2012 and 2011. First, the atmosphere across the Atlantic is expected to be more unstable than what was seen in 2011 and 2012. Additionally, the Caribbean has the possibility of seeing average or even slightly above average unstable conditions. What does this mean? An unstable atmosphere promotes thunderstorms and large areas of disturbed weather which in many cases leads to the development of tropical storms and hurricanes.

It seems plausible this year that we will see more intense convection along the Inter-Tropical Convergence Zone, something that was not seen last year. In fact, this seems to already be occurring, especially across the African continent.

A positive TNA signal and a strong position AMO is likely to not only promote tropical storm and hurricane development this season, it is also likely to favor a high pressure ridge very near the southeastern United States. Also a negative NAO which is present should lead to a high landfall risk across much of the southeastern United States and the eastern & central Gulf states centered right on the Florida Peninsula. Additionally, there is the possibility of southeast Florida being impacted by a major hurricane this season. In closing, it seems very possible that we will see an active year in terms of landfalling tropical storms and hurricanes with a emphasis on the Florida Peninsula. This hurricane season seems poised to be very much different than what we saw in 2011 and 2012.

It seems like a lot of the professional mets are saying Florida is in the bullseye this year. It will be interesting to see if we get hit down here this year or not.

[cycloneye]

Searching thru the net found a very interesting site that has many links to information about African Waves and more that is good to follow as we approach the start of the season and wait for the first wave to emerge to see how the pattern in that continent will be in the next few months.

http://www.atmos.albany.edu/student/janiga/

[cycloneye]

Here is the latest Global Hazard analysis for the next two weeks especially for the Western Hemisphere. Week 2 looks to have plenty of moisture for the Caribbean and maybe more? Read below

The MJO was active during the past week with the enhanced phase centered over the Indian Ocean. An atmospheric Kelvin wave coupled with the MJO contributed to a pair of tropical cyclones developing across the southern Indian Ocean and Bay of Bengal. Short-lived Tropical Cyclone Jamala developed in the southern Indian Ocean on May 9 but quickly weakened due to vertical wind shear. Meanwhile, Tropical Cyclone Mahasen formed over the very warm waters of the Bay of Bengal on May 11. As of May 14, Tropical Cyclone Mahasen is forecast to track north towards Bangladesh. Please see the latest forecasts from the Joint Typhoon Warning Center.

Dynamical model MJO index forecasts indicate a weakening signal during week-1. The enhanced phase of the MJO is forecast to shift east across the Maritime Continent during week-1 with the suppressed phase over the Americas. Due to a weak MJO signal among the dynamical model MJO index forecasts during week-2, identifying anomalous convection across the global tropics is a challenge beyond week-1.

The Week-1 outlook is based on MJO precipitation composites, dynamical/statistical model forecasts, and where anomalous convection is currently ongoing and likely to persist. Above average rainfall is likely along the track of Tropical Cyclone Mahasen as it is forecast to affect Bangladesh later this week. MJO precipitation composites and model guidance favor above (below) average rainfall across the Maritime Continent (Central America and the western Caribbean Sea). Ongoing convection, associated with an equatorial Rossby wave, along with model guidance supports the forecast of above average rainfall across the western Indian Ocean. Increased chances for below average rainfall are forecast across the Lake Victoria region of equatorial Africa and southern Sudan due to expected low-level divergence. Meanwhile, enhanced convection is currently observed across the east Pacific. Model guidance indicates the development of a weak surface low in this region early in week-1. Therefore, moderate confidence exists for tropical cyclogenesis during week-1 across the east Pacific.

The Week-2 outlook is based primarily on dynamical model forecasts since uncertainty is high regarding the evolution of the MJO. Models are in reasonably good agreement for above (below) average rainfall across Central America/southwest Caribbean Sea (equatorial western Indian Ocean). Conditions for the formation of an early season tropical cyclone could become favorable by the beginning of June across the southwest Caribbean Sea.

[cycloneye]

The May UKMET precipitation forecast for the peak of the season (ASO) is wet for MDR/Caribbean.

http://www.metoffice.gov.uk/research/cl ... s/ens-mean

[cycloneye]

Neutral pressures in the MDR and Caribbean and that is a reverse from the April one that had higher pressures.

ECMWF May MSLP Forecast for August, September,October



http://www.ecmwf.int/products/forecasts ... 0summary!/

[blp]

ECMWF May MSLP Forecast for August, September,October

Neutral pressures in the MDR and Caribbean and that is a reverse from the April one that had higher pressures.

You beat me too it. Big difference to me. I think the next forecast might actually show some below normal pressures.

See comparison.
May


Uploaded with ImageShack.us

April


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[cycloneye]

The ECMWF May Ensembble mean has dead neutral pressures.

[cycloneye]

GFS and ECMWF are different on the forecast of the MJO progression. GFS goes into the Atlantic basin while ECMWF restarts in the Indian Ocean. The battle of the titans rages on.

GFS



ECMWF

[robbielyn]

so what does these dead neutral pressures now suggest in relation to this thread?

[cycloneye]

so what does these dead neutral pressures now suggest in relation to this thread?

Neutral pressures cause the steering pattern to be more condusive to CV systems to track more west depending on the orientation of the Bermuda High. Also, with Neutral pressures the indicators are for favorable conditions in the MDR area than if higher pressures establish there.

[robbielyn]

thank you very much for the explanation : )