2013 Steering Pattern / Early indicators

[Riptide]

There are signs of the low instability pattern breaking down with the increasing Intertropical Convergence activity. Much improved over last year...

[Hurricaneman]

There are signs of the low instability pattern breaking down with the increasing Intertropical Convergence activity. Much improved over last year...

http://www.ssd.noaa.gov/PS/TROP/TCFP/da ... xyains.gif

If this really is a pattern shift, this could get really ugly for any possible hurricane landfall so it really is a thing to keep an eye on

[Riptide]

There are signs of the low instability pattern breaking down with the increasing Intertropical Convergence activity. Much improved over last year...

http://www.ssd.noaa.gov/PS/TROP/TCFP/da ... xyains.gif

If this really is a pattern shift, this could get really ugly for any possible hurricane landfall so it really is a thing to keep an eye on

Yes, the atmospheric pressures are below average in relation to climate averages currently. I have been worried about this year since 2011 as we are coming out of a multi-year la nina followed by neutral/weak-el nino conditions, somewhat similar to 2005.

Current Mean Sea Level Pressure


Daily Average

[Riptide]

Current and forecasted vertical wind shear profiles show a continuation of below average wind shear in the Tropical Atlantic.

[cycloneye]

Another thing to watch in the comming weeks will be how the NAO behaves because a negative NAO means warmer sst's in MDR. The GFS ensembles forecast that for late Febuary/early March timeframe.Let's see how things evolve with the NAO by May/June/July.

[xcool22]

what is analog year!!!!! ???

[vbhoutex]

what is analog year!!!!! ???

An analog year is a previous year where the weather patterns match or closely match those that are occurring or expected to occur during the year being discussed.

[xcool22]

okay thanks

[tolakram]

Not sure what some are using to see vertical instability, I use this page: http://www.ssd.noaa.gov/PS/TROP/TCFP/atlantic.html

Tropical Atlantic is still way below normal.

[Riptide]

Vertical instability is still below average but there is a slight improvement trend with new activity over Eastern Africa that may translate downstream. The Mean Sea Level Pressures are not particularly high which is a good sign for instability. Looks lower than last year...

[wxman57]

Last year at this time, the vertical instability in the tropical Atlantic was normal to a bit above normal. It's a lot less/lower this year. Instability has been lacking the past 2 seasons, though we've had 19 named storms each year. Many of those storms were weak/short-lived, and there was not one hurricane in the MDL in 2012. Most formed in the subtropics. Will the deep tropics be as unfavorable or more so than last year?

2012 Tropical Atlantic Instability:
ftp://rammftp.cira.colostate.edu/schuma ... tatins.gif

[Riptide]

There could be an inverse correlation with instability. Higher instability values in late Winter and early Spring might imply low instability during summer and vice versa. Just speculating but I would not write off the season just because of limited instability.

[cycloneye]

While the low instability goes on in the Tropical Atlantic,in another region Vertical Instability is near normal in the Caribbean. Let's see how it continues to fluctuate in the comming weeks.

[TropicalAnalystwx13]

.

[Hurricaneman]

Heres the instability numbers by region campared to normal

February 20

GOM: Average -11 Current -12 which is 1 below normal instability

Carribean: Average -1 Current -1 normal instability

East Coast: Average -12 current -11 which is 1 above normal instability

Tropical Atlantic: Average -1 Current -7 which is 6 below normal instability

Subtrop Atlantic: Average -9 current -12 which is 3 below normal instability

so if you add up all the instability numbers through all regions it equals 9 below normal instability which if this continues through hurricane season could stiffel development if it remains as is

I will be doing daily updates to this to see if there's any change from now until the peak of hurricane season

[cycloneye]

Heres the instability numbers by region campared to normal

February 20

GOM: Average -11 Current -12 which is 1 below normal instability

Carribean: Average -1 Current -1 normal instability

East Coast: Average -12 current -11 which is 1 above normal instability

Tropical Atlantic: Average -1 Current -7 which is 6 below normal instability

Subtrop Atlantic: Average -9 current -12 which is 3 below normal instability

so if you add up all the instability numbers through all regions it equals 9 below normal instability which if this continues through hurricane season could stiffel development if it remains as is

I will be doing daily updates to this to see if there's any change from now until the peak of hurricane season

Thanks for bringing those interesting stats. Keep them comming.

[cycloneye]

There is a difference in the sst anomalies between 2012 and 2013 as the Tropical Atlantic is warmer than last year. Also there is a difference in the Pacific with less warm waters in 2013 than in 2012.

20th of Febuary 2012.



21rst of Febuary 2013.

[cycloneye]

Another thing to watch in the comming weeks will be how the NAO behaves because a negative NAO means warmer sst's in MDR. The GFS ensembles forecast that for late Febuary/early March timeframe.Let's see how things evolve with the NAO by May/June/July.

http://i46.tinypic.com/263va68.jpg

The operational GFS and ECMWF continue to forecast negative NAO for the next 2 weeks. The bigger question going forward is how this factor will be by May,June,July,August and September.

[Ntxw]

We had a little discussion earlier today in the Texas thread about the -PDO/+AMO periods. Wxman57 mentioned that the 40s, 50s, and 60s were very identical to the oceanic cycle as today's with those two couplets which featured numerous hits for the northeast (Hazel, Carol, Donna, Edna etc). The past two seasons the northeast coast of the US have been directly effected by substantial cyclones (Irene, Sandy), with the subtropics continuing to be favorable for systems I would think this season and the next several will be the same giving higher threat again to the big populations of the mid-Atlantic and New England coasts.

I suspect cycloneye's watch of the NAO has some influence from these cycles as well. Those years favored very much the -NAO (Greenland block). This traps storms from recurving into Atlantic Canada or out to sea since it is a block and storms cannot drive into blocks making bee lines into the US coast.

[HURRICANELONNY]

Looking at the early indicators as cycloneye and others post. It looks like were SCREWED! Bad year coming.