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Tropical Thread 2013


phlwx

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ENSO -- likely neutral throughout, perhaps slight lean cool.

Atlantic -- east/central tropical is warm. Gulf cool as of now.

 

I'm going 18/9/3 for the season.

 

Like the 04 analog that CSU is pushing although I don't think it will be as active for Florida in sheer quantity.

 

 

 

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should be interesting to see what the tropical entity down in in the BOC does. Some models show it meandering its way up here, hooking up with an ULL dropping out of canada (GFS)

euro just has it meandering under a ridge......

Something to watch next week at least.

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should be interesting to see what the tropical entity down in in the BOC does. Some models show it meandering its way up here, hooking up with an ULL dropping out of canada (GFS)

euro just has it meandering under a ridge......

Something to watch next week at least.

Yeah, at the very least, looks like a big rain event for the SE US. Not sure how quickly it will get picked up and if its moisture will make its way up here.

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30% chance from the system in the gulf. Looks highly sheared now though. Should see some rain from it around the Saturday timeframe. I see the front stalling with perhaps a predecessor rainfall event along the front ( Not sure on semi-tropical systems). Will be interesting. Also will be a zone of subsistence and little rain setting up right over Mount laurel.  :underthewx:

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30% chance from the system in the gulf. Looks highly sheared now though. Should see some rain from it around the Saturday timeframe. I see the front stalling with perhaps a predecessor rainfall event along the front ( Not sure on semi-tropical systems). Will be interesting. Also will be a zone of subsistence and little rain setting up right over Mount laurel.  :underthewx:

I think you mean subsidence, unless poor Tony is going broke :o

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30% chance from the system in the gulf. Looks highly sheared now though. Should see some rain from it around the Saturday timeframe. I see the front stalling with perhaps a predecessor rainfall event along the front ( Not sure on semi-tropical systems). Will be interesting. Also will be a zone of subsistence and little rain setting up right over Mount laurel.  :underthewx:

and the gfs wants that to be over our area

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I can't get over how impressive the ITCZ has been this year over the Atlantic. The last two rounds of KW/MJO activity have shown some really impressive signatures in the Atlantic. If we keep this up, true hurricane season will probably kick up earlier than usual (mid-late July?).

 

In 2011 and 2012 during spring (and most of the year actually), the mean Walker Uplift was over the Indian Ocean. Not only was that responsible for the warm winter, but it was contributing to the poor Atlantic Instability during tropical season. This year, the mean uplift zone is right over 120E just about. There is mean downward motion, actually, over the western IO / eastern Africa contributing to the IOD switch, as well.

 

It is quite possible among the changes in the IO, lack of El Niño and AMO state, that this year will feature higher ACE / octane!

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This year, the mean uplift zone is right over 120E just about. There is mean downward motion, actually, over the western IO / eastern Africa

 

I've noticed this as well. I haven't done any diagnosis as to why that's the case, but it's pretty evident for the last 45 days or so

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I've noticed this as well. I haven't done any diagnosis as to why that's the case, but it's pretty evident for the last 45 days or so

 

The other thing to take note of is how freakin warm it is between 90E-150E from about 25N down. The 30C line is pushing 20N now out there. In some regard, this could be the IOD-ENSO squeeze play in action, speeding up the annual cycle. The -IOD is already beginning to affect things across the Africa-W. Pac Sector for sure and some folks are suggesting the Indian Monsoon may be weaker than normal due to it. Of course, I'm not buying that linear thought because the rapid switch to a +IOD last season didn't seem to help. There is more to the monsoonal circulations than the IOD, as you know.

 

70mb is pretty cool overall along the equatorial Pacific in the last week or so while 50mb and up has rapidly turned +QBO like. We have also seen some enhancement, poleward of the subtropical anticyclones on both sides of the equator as westerly momentum is added from above. Finally, the sun recently came back to life over the last 2 weeks (could aid in this process of poleward anticyclones...could is the operative word).

 

None of this, of course, directly answers why since this is likely a combination of lag/past regimes with new changes.

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I'll just spout whatever the Euro ensemble says with an ALERT tagline

 

Sounds like I'm missing some funny tweets. I can't access anything useful at the office (gmail, twitter, basically anything that causes trouble haha). I'm  just waiting for the day that my access to Americanwx is cut because most forums are not allowed. This one slipped through the cracks.

 

ALERT, ALERT...MJO in phase X means rainfall for location Y...ALERT, ALERT....

 

sigh...

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Sounds like I'm missing some funny tweets. I can't access anything useful at the office (gmail, twitter, basically anything that causes trouble haha). I'm  just waiting for the day that my access to Americanwx is cut because most forums are not allowed. This one slipped through the cracks.

 

ALERT, ALERT...MJO in phase X means rainfall for location Y...ALERT, ALERT....

 

sigh...

I don't follow him on twitter but a lot of the aleet  aleet are on facebook where he regurgitates the euro and its ens

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this goes out to HM and Adam and whoever else said their would be a period of tropical activity a couple weeks out. How do you guys determine when the look is right for tropical activity. I mean i can see how its an east coast threat with the atlantic high nosing westward.

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this goes out to HM and Adam and whoever else said their would be a period of tropical activity a couple weeks out. How do you guys determine when the look is right for tropical activity. I mean i can see how its an east coast threat with the atlantic high nosing westward.

 

Kudos indeed....anyone feel this is only our first brush with tropical/ tropical remnants threats this season for our region?

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this goes out to HM and Adam and whoever else said their would be a period of tropical activity a couple weeks out. How do you guys determine when the look is right for tropical activity. I mean i can see how its an east coast threat with the atlantic high nosing westward.

 

Using intraseasonal oscillations in conjunction with the bigger factors (enso/qbo/solar etc.) to determine patterns is how it can be done. You can give a general heads up for a time period of interest when these things point in a certain direction. You can't have 1 without the other either. A lot of forecasters will rush the process, too, and I have been guilty of that several times. The trick is waiting for the wave to pass through the basin when you'll see the most accumulation of potential vorticity, moisture and low-level westerly wind anomalies. Remember always that climo must be embedded within your forecast as well as your year's unique traits (this year's ITCZ, for example, has been exceptionally strong this spring).

 

The few years where I tried forecasting dates, with reasonable success, I was trying to anticipate when these individual accumulated quantities and certain solar wind qualities peaked favorably over the Atlantic-side.

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Using intraseasonal oscillations in conjunction with the bigger factors (enso/qbo/solar etc.) to determine patterns is how it can be done. You can give a general heads up for a time period of interest when these things point in a certain direction. You can't have 1 without the other either. A lot of forecasters will rush the process, too, and I have been guilty of that several times. The trick is waiting for the wave to pass through the basin when you'll see the most accumulation of potential vorticity, moisture and low-level westerly wind anomalies. Remember always that climo must be embedded within your forecast as well as your year's unique traits (this year's ITCZ, for example, has been exceptionally strong this spring).

 

The few years where I tried forecasting dates, with reasonable success, I was trying to anticipate when these individual accumulated quantities and certain solar wind qualities peaked favorably over the Atlantic-side.

Not to put you on the spot, when is your next time frame that you are liking for tropical development, either you or adam. Can the mjo be used as a tool to? Does that have any effects on the ITCZ?

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MJO, Kelvin wave, and equatorial Rossby wave forecasts are my primary tools for forecasting favorable periods for cyclogenesis

What do you look for in regards to the mjo, like what phases promote increase wave production and atlantic high that blocks a storm from re curving?

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What do you look for in regards to the mjo, like what phases promote increase wave production and atlantic high that blocks a storm from re curving?

Just like winter, I don't really look for phases so much as I look at the hovmollers and try to determine when upper level divergence patterns will be favorable for the Atlantic. For a rule of thumb, P8 and P1 are the best for genesis and P1-3 are best for intensification (because shear relaxes behind the MJO wave).

 

As far as the mid-latitude pattern goes, that's as much NAO as it is position of the Bermuda high. You need to look upstream to try to determine where the mean mid-latitude troughs and ridges will be when the storm is nearing the Antilles. Frankly, my crystal ball isn't nearly as sharp in the warm season to try to figure those things out. 

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Past performance is not necessarily an indicator of future results but...

 

I pulled the nine rainiest Junes back to 1872...there's a relatively strong correlation between June heavy rain and a late August/September tropical threat along the East Coast.

 

1938 -- LI Express

2006 -- Ernesto (TS, but it still came up the coast)

2003 -- Isabel

1906 -- South Carolina landfall in mid Sept (did not impact Philly)

1962 -- Alma (paralleled the East Coast, did not make landfall but 2" of rain in Philly)

1969 -- Gerda (landfall in Maine)

 

We also were impacted by the remnants of Eloise in 1975 (Gulf hit) -- dropped 4" of rain on us in mid/late September.

 

One could argue, yeah, we have a "threat" nearly every year but the tendency is pretty strong that a rainy June tends to set up the possibility of a mid season tropical hit/close call along the East Coast somewhere.

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