Atlantic Tropical Action 2013

[jordanwx]

That is an impressive MODIS image. And while I agree that SAL has ben below normal recently (last 10 days or so), there were plenty of SAL outbreaks in the earlier portion of this month that are on the same scale as this recent SAL intrusion.

 

e.g. July 8th

 

 

Compared to now

 

 

In the end, this is a silly thing to be arguing over... I agree with Mike that the overall pattern with increased rainfall over the Sahel should favor less dust coming off the African continent overall, although it obviously won't prevent it entirely, even larger outbreaks. 

Yeah it is a silly thing to argue over, didn't mean to cause problems. Just wanted to clarify things. Also, in that first image you posted, much of those reds that are showing up north of 20N probably aren't a result of SAL. Gotta be careful when using the CIMSS "SAL" product. It doesn't actually measure the SAL we think it does (aerosol/dust-laden, dry air from the Saharan desert). What it actually measures is low-mid level dry air, which may or may not include SAL. That's why I provided the MODIS image above to highlight the aerosols and dust associated with the latest SAL outbreak. See the SAL product description for more info.

[bluewave]

Cool stats, Chris.  Can't believe 2001 and 2002!  Didn't know that.

 

Sure, Josh. 2011 and 2007 were the most recent non-Nino seasons.

 

Total named storms

 

2011....19

2007....15

2001....15

1999....12

1998....14

[phil882]

Yeah it is a silly thing to argue over, didn't mean to cause problems. Just wanted to clarify things. Also, in that first image you posted, much of those reds that are showing up north of 20N probably aren't a result of SAL. Gotta be careful when using the CIMSS "SAL" product. It doesn't actually measure the SAL we think it does (aerosol/dust-laden, dry air from the Saharan desert). What it actually measures is low-mid level dry air, which may or may not include SAL. That's why I provided the MODIS image above to highlight the aerosols and dust associated with the latest SAL outbreak. See the SAL product description for more info.

 

Yes, yes, I agree, although you can argue that dry air from any source is not necessarily going to be a good thing for a TC (case in point, Dorian still struggled in a relatively SAL free [but still very dry] mid-level environment when the shear increased). This particular outbreak, as shown above, is actually showing up really well on visible imagery as well which doesn't happen too often. 

[HurricaneJosh]

SAL debate.  What an exciting tropical season.

[icebreaker5221]

Yes, yes, I agree, although you can argue that dry air from any source is not necessarily going to be a good thing for a TC (case in point, Dorian still struggled in a relatively SAL free [but still very dry] mid-level environment when the shear increased). This particular outbreak, as shown above, is actually showing up really well on visible imagery as well which doesn't happen too often. 

 

 

Well, if nothing else, that's something to track.    A lot of the times they're very obvious when they blow through S. FL when they show up in vis like that.  This one being so far south makes me believe it's got a chance. 

 

Sometimes almost as bad as these webcam shots from St. John:

http://www.accuweather.com/en/weather-news/dense-saharan-dust-travels-to-florida/68145

[HurricaneJosh]

OK, it's August.  Time for a mental reset.  New month = new attitude... and hopefully new patterns.

[Mike.Ventrice]

[Ellinwood]

The first TWO that goes out to 5 days, and...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT FIVE DAYS.

[Ed Lizard]

Does anyone legitimately expect tropical cyclone formation in the next 10 days?  Fifteen?

[bluewave]

Does anyone legitimately expect tropical cyclone formation in the next 10 days?  Fifteen?

 

If it goes 15, that would be the first time for the Atlantic since 1999 without a named storm August 1-15.

[Mike.Ventrice]

If it goes 15, that would be the first time for the Atlantic since 1999 without a named storm August 1-15.

 

I'm thinking it may hold off to August 15-31. The next suppressed CCKW is coming around. I had high hopes for the previous MJO event that just fizzled!

 

[Ed Lizard]

If it goes 15, that would be the first time for the Atlantic since 1999 without a named storm August 1-15.

 

If I can't see more than a hint that one or two of the Canadian members of the NAEFS try to develop something in a 16 day period, I just get the feeling a boring couple of weeks is coming.

 

Euro had several runs of a frontal trough making a move at developing in the NE Gulf and moving WSW, but last couple of runs don't seem to show even that. 

 

No sea breeze storms, 16 day GFS rainfall totals locally in SETX been under an inch, and no football for another month, just the pathetic Astros, a tropical depression indeed.

[Chinook]

This is not exactly related to the Atlantic season. I found that the COD web page now has a "world view" for the GFS, and it's pretty easy to scroll through different hours.

 

http://weather.cod.edu/forecast/

[icebreaker5221]

SAL debate.  What an exciting tropical season.

 

Don't like talking about the SAL?  How about the shear?

 

Holy wind shear Batman!  Not too often you see 85-90 kts of wind shear in the Caribbean in August.

 

[DopplerWx]

Is there any good news at all?  Sheesh I hope latter August and Sept are active.

[Ed Lizard]

Don't like talking about the SAL?  How about the shear?

 

Holy wind shear Batman!  Not too often you see 85-90 kts of wind shear in the Caribbean in August.

 

gfs_shear_watl_32.png

That kind of shear is easy to get w/ 45 knot low level Easterlies.

 

[AvantHiatus]

What is that cluster of thunderstorms in the Bahamas? Appears to be primed for development.

 

[wxmeddler]

What is that cluster of thunderstorms in the Bahamas? Appears to be primed for development.

 

Ex- Dorian. No development expected. Rain for FL.

[Superstorm93]

This is actually rather interesting. 

 

I could see how the NHC could make this an invest at some point. 

 

[phil882]

None of the dynamical models are excited about Ex-Dorian for development but it is currently in a pocket of low shear after the upper-level low thats been shearing it apart has finally retrograded to the southwest. The low-level vorticity is still rather poor, but the shear is expected to remain relatively low for the next 48 hours. 

 

Hot off the presses!

 

 

1. CLOUDINESS AND THUNDERSTORMS ASSOCIATED WITH THE REMNANTS OF DORIAN
HAVE BECOME MORE CONCENTRATED ALONG A TROUGH OF LOW PRESSURE IN THE
CENTRAL AND NORTHWESTERN BAHAMAS TODAY. ALTHOUGH SURFACE PRESSURES
ARE FALLING IN THIS AREA...THERE ARE NO SIGNS OF A CLOSED
CIRCULATION. THIS DISTURBANCE IS FORECAST TO MOVE TOWARD THE
NORTHWEST AND NORTH...BRINGING CLOUDINESS...SHOWERS...AND GUSTY
WINDS TO PORTIONS OF THE NORTHWESTERN BAHAMAS AND THE COASTAL
WATERS OF SOUTHEASTERN FLORIDA ON FRIDAY AND SATURDAY. AFTER
THAT...THE DISTURBANCE IS EXPECTED TO MOVE TOWARD THE
NORTH-NORTHEAST AND BECOME ASSOCIATED WITH A FRONTAL TROUGH. THIS
SYSTEM HAS A LOW CHANCE...20 PERCENT...OF BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS...AND A LOW CHANCE...20
PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS.

[Ed Lizard]

91L deactivated a couple of days ago, just reactivated.

 

 

http://ftp.nhc.noaa.gov/atcf/tcweb/invest_DEACTIVATE_al912013.ren

 

http://ftp.nhc.noaa.gov/atcf/tcweb/invest_RENUMBER_al042013_al912013.ren

[phil882]

That kind of shear is easy to get w/ 45 knot low level Easterlies.

 

 

Thats very impressive low-level jet! With that said, thats bound to produce a large area of shear vorticity in the southern Caribbean superimposed on an area of upper-level divergence associated with the TUTT cell in the Caribbean. As the TUTT cell retrogrades west, it might give way to a favorable upper-level pattern in the southern Caribbean by the end of the medium range... where in the day 8-10 range the operational GFS shows a TC being spawned.

[Superstorm93]

Quite a wave off of Africa

 

[GaWx]

 _{The MJO is projected to mainly be within the circle for much of the next two weeks fwiw. Based on August genesis stats for the current +AMO, it tends to be more of a hindrance than a help for genesis chances although the U.S. hitting Irene of 2011 and Katrina of 2005 did form when the MJO was within the circle.}

 

 

_{TC geneses per day/MDR TC geneses per day/US direct H hit TC geneses per day:}

 

_{Days Within Circle: 10%/5%/1% (Irene ’11, Katrina ’05)}

 

_{ALL days: 14%/8%/2%}

 

 

_{Note that all three %'s pertaining to being within the circle are lower than the respective %'s for all days combined. For those who want activity in August, the best case scenario MJOwise would be for it to go into phase 3:}

 

_{Days within Phase 3: 38%/25%/3% (Fran ’96)}

 

 _{Look at how high those first two %'s are for phase 3! That means that on any given single day based on stats since 1995 in August during phase 3, more than 1/3 of the days had a genesis and 1/4 had a genesis in the MDR!!  If these were close to the true underlying probabilities, that means that there's a better than even chance of a genesis when there is a period of just two days in phase 3! Those are some impressively high odds.}

 

_{Look at how high those first two %'s are for phase 3!}

[GaWx]

Josh or anyone else,

 Was Hurricane King of 1950 a major H hit on Miami or not? I'm seeing conflicting info!

[HurricaneJosh]

Josh or anyone else,

 Was Hurricane King of 1950 a major H hit on Miami or not? I'm seeing conflicting info!

 

Yes, KING 1950 was absolutely a major at landfall in SE FL.  The HURDAT wind speeds are wrong and will be corrected when this period is reanalyzed.

 

The question among the reanalysis reasearchers was whether it was a Cat 3 or 4 when it made landfall near Miami.  It was a tiny but very violent microcane.  They settled on 110 kt (strong Cat 3), and that's what they've recommended to the Best Track Committee.

[GaWx]

Yes, KING 1950 was absolutely a major at landfall in SE FL.  The HURDAT wind speeds are wrong and will be corrected when this period is reanalyzed.

 

The question among the reanalysis reasearchers was whether it was a Cat 3 or 4 when it made landfall near Miami.  It was a tiny but very violent microcane.  They settled on 110 kt (strong Cat 3), and that's what they've recommended to the Best Track Committee.

 

 Thanks, Josh! I'm looking at some data for cool Augusts in the US as a whole that might be encouraging for you and other U.S. chasers as regards the rest of the season. 1950 apparently was the coolest August since 1950 for the US as a whole based on a certain population weighting. The next coolest: 1992, 2004, 1976, 1967 and 1964. I assume you see where I'm going.

[Amped]

1950 had 11 hurricanes and 8 majors out of 16 storms. We can only dream of numbers like that.

[GaWx]

1950 had 11 hurricanes and 8 majors out of 16 storms. We can only dream of numbers like that.

 

 I don't know if you saw what I just posted as an edit. 1950 was the coolest August between 1950 and 2012 by one measure based on population weighting..i.e., chilly in much of the E and central US. 2013 is strongly leaning cool right now.

[HurricaneJosh]

 Thanks, Josh! I'm looking at some data for cool Augusts in the US as a whole that might be encouraging for you and other U.S. chasers as regards the rest of the season. 1950 apparently was the coolest August since 1950 for the US as a whole based on a certain population weighting. The next coolest: 1992, 2004, 1976, 1967 and 1964. I assume you see where I'm going.

 

Wow, yeah-- that's a pretty-cool factoid.  Except for 1976, all those years had major American landfalls.  Hopefully there's some hard-coded connection.  

 

P.S.  You're welcome for the KING info.  That's one of my all-time favorite cyclones, so I'm pretty close with the data on that one.