Seasonal Indicators (Beyond Day 16): Instability / SST's / MSLP / Steering / Sal

[tolakram]

Ninel has been correct for a few years in a row now concerning that pattern. I think there's more than a 1% chance of something sneaking through but the overall pattern does tend to protect the US and has been recognized by a few hurricane forecasters now.

I do wonder, though, if we clearly understand the cause and effect. If conditions are quite favorable in the western Atlantic other than the trough pattern will this indeed extend the streak or will development change the pattern. I'm not sure how accurate it is to say summer patterns don't change.

[CYCLONE MIKE]

^^^That's ridiculous, like RIDICULOUS. No one can authoritatively make such a pronouncement on August 

That I don't agree with. We have seen season after season come August just how hostile conditions across most of the basin have been with the pattern ninel is talking about, and the pattern has never broken. If its still the same by August, chances of the light switch flipping on and it suddenly becoming super conducive are slim to none no matter how many people say just wait two more weeks.

[Steve]

There is no guarantee that we will or won't be in a primary trough situation or that anyone will or won't be hit or there will or won't be any hurricane or major hurricane hits on the USA. This is shaping up to be a western biased Atlantic Storm season, and storms B and C have formed west and impacted the United States with 2 landfalls already. Often in seasons that have a western bias, we see more shorter lived storms and TS hits on the US. Whether August and September end up having one or more H or IH landfalls is unknown. But a mean Western Atlantic trough doesn't mean much to me outside of being a concerned American. I'm way more worried about anything coming out of the Caribbean than something approaching the East Coast north of Daytona. I don't like South Florida hits because they often portend a later hit on Louisiana (ref Betsy, Andrew, Katrina, etc.)

However, if anyone would like to take a bet this year that the USA doesn't get hit by at least a hurricane, I'm in for a 50.00 donation to the site. I'm only betting against whoever takes the bet first, but anyone is welcome to join in. 50.00 says we take a H or IH hit in the USA in 2016 regardless of all patterns, mslp anomalies, etc.

[Ntxw]

I think it's mostly luck and timing, some persistence of the two. Plus the east coast trof pattern can bring a hit too, via drawn up from the Caribbean. We just haven't seen above normal activity in the Carib in quite some time (hence the graveyard label lately). I mean the last time the Carib had a real season with lots of ACE (more than just a cane or two spread out) was 2008. That was a long time ago.

[WPBWeather]

It is somehow strangely reassuring to see a few of the returning posters who are always strongly convinced of their respective positions on the season. Again, I won't bet the roof on it though.

[SouthDadeFish]

Such confidence of a dominant east coast trough preventing hurricane landfalls this far in advance is foolish in my opinion. Even with a long term pattern supporting an east coast trough, all you need is a temporary shift from the pattern to get a landfall. Also, where was this "11-year trough" in 2008 with Hurricane Ike? Ike actually missed FL to the south due to a strong ridge. Regarding FL in particular, numerous hurricanes have impacted the state in the month of October due to an upper-level trough bringing storms out of the NW Caribbean.

[Steve]

For sure South Dade.

For the devils advocate point of view, lots of systems recurve. But having dealt with Cindy, Dennis, Katrina, Rita, Gustav, Ike, Isaac, and a couple of invests over the last 11 years and whatever else I have forgotten, it didn't matter much in the end. that's plenty of crazy for the last 11 years.

[Hammy]

Based on where the ridge will set up once again for the 11th consecutive year we will have a summer long wnw flow over the west atlantic with a big west atlantic trof. FLA cane drought will continue and this will be year 11 of no major canes hitting the US. A big warning sign was the continued CA drought despite a super el nino. Nothing can get rid of the 11 year west atlantic trof. I know some people will say if something times it just right then there might be a 1% chance of something hitting land but as has happened every year as we head toward aug/sept the trof will simply get stronger and stronger. Bermuda high might be just something talked about but never seen.

^^^That's ridiculous, like RIDICULOUS. No one can authoritatively make such a pronouncement on August 15th, much less June 15th. We are THREE MONTHS away from the peak of hurricane season. Let that sink in. That is a quarter of a year.

Perhaps. Another good point to make was the slow severe weather season once again. WNW flows across the east is a hallmark of slow severe weather seasons.

I'll point out that last year had favorable steering, and without the shear both Danny and Erika would've likely ended up as Florida hurricanes. This year may have a similar pattern, if the early part of the year is any indication, but as per models we likely won't have the massive wall of shear that we had last year so I would not entirely rule out something hitting the Southeast. It's also more likely than the last several years that the Gulf/Caribbean will be more active, based on all the forecasts I've seen. If that comes to pass then the troughs will actually work in favor of Florida being hit.

[NDG]

^^^That's ridiculous, like RIDICULOUS. No one can authoritatively make such a pronouncement on August 15th, much less June 15th. We are THREE MONTHS away from the peak of hurricane season. Let that sink in. That is a quarter of a year.

Perhaps. Another good point to make was the slow severe weather season once again. WNW flows across the east is a hallmark of slow severe weather seasons.

I'll point out that last year had favorable steering, and without the shear both Danny and Erika would've likely ended up as Florida hurricanes. This year may have a similar pattern, if the early part of the year is any indication, but as per models we likely won't have the massive wall of shear that we had last year so I would not entirely rule out something hitting the Southeast. It's also more likely than the last several years that the Gulf/Caribbean will be more active, based on all the forecasts I've seen. If that comes to pass then the troughs will actually work in favor of Florida being hit.

Yeap, last year both Danny & Erika would had affected the US had it not been for the record breaking windshear across the Caribbean, there was strong ridging to the north of them unlike previous years, (2010-2014)

[Patrick99]

You can have troughs all season long for the most part, but if the troughs take a break for one week in September, and a system exists to take advantage of that, it's game over.

My feeling on the whole "East Coast Trough" thing, is, we've just been extraordinarily "lucky." No season sees a trough draped all the way down the coast from Maine to West Palm, constantly. It's just that whenever there has been a pattern more favorable for US hits, there's been nothing in the pipeline

[SFLcane]

You can have troughs all season long for the most part, but if the troughs take a break for one week in September, and a system exists to take advantage of that, it's game over.

My feeling on the whole "East Coast Trough" thing, is, we've just been extraordinarily "lucky." No season sees a trough draped all the way down the coast from Maine to West Palm, constantly. It's just that whenever there has been a pattern more favorable for US hits, there's been nothing in the pipeline

There's has been nothing down pipeline due to mostly shear and dry air basin wide but this year those might not be there. Actually we haven't really seen the Atlantic in a favorable state for years so this season might bring a few suprises.

[TheStormExpert]

Couldn't of said it better Hammy and NDG! Last season if it were not for the Super Strong El Niño creating record strong decapitating wind shear throughout the entire Caribbean Erika and Danny would have likely hammered Florida as hurricanes!

So for anyone who says that the pattern has not been there for hurricanes to hit Florida from the East were probably not around to see Erika being forecasted to hit or impact SE FL as a hurricane by the NHC for several days. We had the pattern last season just not the favorable upper level conditions. That could likely change in the coming year(s).

[TheStormExpert]

You can have troughs all season long for the most part, but if the troughs take a break for one week in September, and a system exists to take advantage of that, it's game over.

My feeling on the whole "East Coast Trough" thing, is, we've just been extraordinarily "lucky." No season sees a trough draped all the way down the coast from Maine to West Palm, constantly. It's just that whenever there has been a pattern more favorable for US hits, there's been nothing in the pipeline

Exactly! A perfect season that comes to mind where the truoghs and ridges worked against or favor was 2004.

Hurricane Charley in mid August of that year was pulled North and East out of the Western Caribbean by an extremely strong trough for mid August standards, this allowed Florida to experience their first of many hurricane hits that season along with the first hurricane to hit Florida I believe since Irene(1999).

Within the next 3 weeks after Charley the steering pattern did a huge 180° flip to a strong East Coast or Western Atlantic ridge which allowed both Frances & Jeanne to impact East-Central Florida both making landfall in the exact same location just 3 weeks apart. Ivan too was pulled north through the GoM out of the Caribbean around the stronger than normal ridging making landfall in extreme SE Alabama with the worst effects being felt in the extreme Western FL Panhandle.

Like some who have said just recently that summer patterns NEVER CHANGE is not correct! The do change from time to time, and sometimes like in 2004 in a BIG way.

[Yellow Evan]

You can have troughs all season long for the most part, but if the troughs take a break for one week in September, and a system exists to take advantage of that, it's game over.

My feeling on the whole "East Coast Trough" thing, is, we've just been extraordinarily "lucky." No season sees a trough draped all the way down the coast from Maine to West Palm, constantly. It's just that whenever there has been a pattern more favorable for US hits, there's been nothing in the pipeline

Even if the troughs take a break for one week, you still need the right timing and conditions for a major hit. for instance, Erika and Danny's problem for instance would have been land interaction and in Danny's case, it's small size. Neither would have been monster hurricanes. In order to get a USA hit at this point in the pattern we've seen for almost 8-10 years, the ITCZ needs to stay south or we need a break from the East coast troughing AND favorable conditions AND needs to avoid land like Hispaniola and Cuba AND then depending track, may need for the right timing of a trough to steer it into the Gulf AND hope it's structure allows for significant intensification AND then hope if steered by a trough in the Gulf, the storm doesn't get torn apart by shear. Lots of hurdles to get through, and that's why I have modest doubts that we will see a major hurricane landfall in the USA this year. Hurricane? Yes, largely because you can get systems of non-tropical origin that form close to home and can hit the USA without too much effort

[NDG]

How things have changed over the Caribbean in just a few days.

[TropicalAnalystwx13]

The Indian Ocean Dipole is more negative this year than at any point over the past five. A negative IOD helps strengthen the West Africa monsoon circulation, as well as enhance convection over the eastern Indian Ocean/Indonesia, leading to more potent tropical waves that have an increased risk for formation once in the Atlantic.

[Alyono]

Couldn't of said it better Hammy and NDG! Last season if it were not for the Super Strong El Niño creating record strong decapitating wind shear throughout the entire Caribbean Erika and Danny would have likely hammered Florida as hurricanes!

So for anyone who says that the pattern has not been there for hurricanes to hit Florida from the East were probably not around to see Erika being forecasted to hit or impact SE FL as a hurricane by the NHC for several days. We had the pattern last season just not the favorable upper level conditions. That could likely change in the coming year(s).

probably not. Erika would still have plowed over Hispañiola. Danny may have stayed south of Florida

[Alyono]

One thing I did not expect was that conditions over the EPAC have been substantially less favorable than expected. Perhaps they will become more favorable in the CPAC later in the year. But that may be too far to have a significant effect on the Atlantic

[Hammy]

One thing I did not expect was that conditions over the EPAC have been substantially less favorable than expected. Perhaps they will become more favorable in the CPAC later in the year. But that may be too far to have a significant effect on the Atlantic

Would an unfavorable E Pacific have a negative or positive impact on storm formation in the Caribbean/Gulf?

[Alyono]

probably make Caribbean more favorable

Gulf was always going to be favorable this year