Dr. Jeff Masters' WunderBlog

Not the worst signature I've seen.

So far this year we have been blessed by some strange happenings in the atmosphere. Weak storm after weak storm, I hope this pattern continues, A storm looks strong and like its going to organize into a tight pattern with lots of convection, then all of a sudden in a few hours its scattered and lost its convection, the only storms hitting south florida are the afternoon thunder boomers sending down torrential down pours flooding streets and gusts of wind, then the sun comes out. Love south florida in the summer

La Nina's return hmmmm

Quoting SouthDadeFish:
That's if the winds are equally spaced for both sets of data, etc. but yeah many interesting calculations can be done. You can also look into the Power Dissipation Index by Kerry Emanuel for more information. He thinks it is a better tool than ACE. It pretty much integrates all activity of the hurricane season using the cube rather than the square of the max winds.

I haven't looked the Power Dissipation Index up just yet, but is there more to it than just using the cube of the velocity? That wouldn't qualitatively change the ACE.

No mention of development but here is the PM discussion from Caribbean/NCEP desk on expected rainfall as 93L passes through:

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
305 PM EDT MON AUG 15 2011

TROPICAL WAVE ALONG 55W IS A FAIRLY PROGRESSIVE WAVE...AND IT IS LIKELY TO FAVOR SQUALLY WEATHER AS IT MOVES ACROSS THE NORTHEAST CARIBBEAN ISLANDS. SOME OF THE MODELS SHOW RISK OF SEVERE CONVECTION WITH THIS FEATURE...TO TRIGGER WATER SPOUTS AND STRONG GUSTY WINDS. IT IS TO FAVOR SCATTERED CONVECTION ACROSS THE ISLAND CHAIN THROUGH 42 HRS...WITH RAINFALL AMOUNTS OF 10-15MM/DAY AND
MAXIMA OF 25-50MM/DAY. ACROSS THE VIRGIN ISLES-PUERTO RICO IT WILL FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM/DAY THROUGH 42/48 HRS...WHILE OVER THE DOMINICAN REPUBLIC-HAITI IT IS
TO FAVOR ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-35MM/DAY. OVER JAMAICA IT IS TO FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM/DAY. STRONG EASTERLIES ARE TO ACCOMPANY THIS FEATURE AS IT PROPAGATES ACROSS THE NORTHEAST CARIBBEAN...WITH
WINDS TO PEAK AT 20-25KT. STRONGER WINDS ARE EXPECTED ON ELEVATIONS ABOVE 2KM.

Way cool space news Link

KHRM

A little more northerly component with 93L?

Quoting xcool:


La Nina's return hmmmm

NOOOOOO!We need rain in Texas!

Apart from having expanded in aerial coverage I see no difference between 93L when it received 20% from the NHC and now. I would go for 20% and wait to see if the convection starts to rebuild before stepping it up to 30% later. Might as well join in the ratings game LOL

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT MON AUG 15 2011

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
STORM GERT...LOCATED ABOUT 135 MILES EAST-NORTHEAST OF BERMUDA.

A TROPICAL WAVE IN THE VICINITY OF THE LESSER ANTILLES IS PRODUCING
A LARGE AREA OF DISORGANIZED CLOUDINESS AND SHOWERS. THERE ARE NO
SIGNS OF A SURFACE CIRCULATION AT THIS TIME AND PRESSURES ARE NOT
FALLING SIGNIFICANTLY OVER THE AREA. ENVIRONMENTAL CONDITIONS ARE
EXPECTED TO BE MARGINALLY CONDUCIVE FOR DEVELOPMENT OF THIS SYSTEM
DURING THE NEXT COUPLE OF AS IT MOVES WESTWARD AT 15 TO 20 MPH OVER
THE CARIBBEAN SEA. THIS SYSTEM HAS A LOW CHANCE...20 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

Quoting robj144:


I haven't looked the Power Dissipation Index up just yet, but is there more to it than just using the cube of the velocity? That wouldn't qualitatively change the ACE.

It quantitatively changes it though. It means that a Cat 4 counts for even more points over a Cat 3 than the ACE would have given it. I guess there is a debate over which exponential function describes the power best.

With the increase in vorticity we saw today, 93L is one sustained convective burst away from attempting to put out an LLC in my opinion. Although it hasn't really sustained convection it's whole life so we will see. By sustained I mean reaching beyond a diurnal cycle.

TWO out, no change and virtually the same writing.

A TROPICAL WAVE IN THE VICINITY OF THE LESSER ANTILLES IS PRODUCING
A LARGE AREA OF DISORGANIZED CLOUDINESS AND SHOWERS. THERE ARE NO
SIGNS OF A SURFACE CIRCULATION AT THIS TIME AND PRESSURES ARE NOT
FALLING SIGNIFICANTLY OVER THE AREA. ENVIRONMENTAL CONDITIONS ARE
EXPECTED TO BE MARGINALLY CONDUCIVE FOR DEVELOPMENT OF THIS SYSTEM
DURING THE NEXT COUPLE OF AS IT MOVES WESTWARD AT 15 TO 20 MPH OVER
THE CARIBBEAN SEA. THIS SYSTEM HAS A LOW CHANCE...20 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

Models are tools,,never Gospel.


They show the trends thru time..and a comparing of the next to the last always gives us a Better understanding of what may occur downstream intime.

Consensus is the key,,

Take the 18Z Runs and compare to the 00Z runs coming out in a Hour or so.

Note the differnce between them and also the runs consensus.

Its showing Climatology as well as the current.

Thats a factor as well.

Thus the CLP series.

But pay attention to "consensus" its always the Canary in da tropical Mine.



18z Early Cycle NHC model tracks
Invest93
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)



)
Dynamic Models (More sophisticated models)

Quoting Patrap:
Anyone seeing those 4 big Cells off the Se Fla Coast this evening?

See them--went thru one of them! Lots of noise north and south of Stuart but minimumal rain, considering all the racket and the wind. Now to go out and pick-up all the palm fronds...........

Is it me, or when the thunderstorms develop west of Lake O and move east, they kind of split up, go around, and miss us. (We are on the coast, even with the top tip of Lake O.) We always seem to get missed when north and south are getting pounded.

Curios as to how they calculated the ACE value of a storm back in 1899?

Quoting GeoffreyWPB:
A little more northerly component with 93L?

I think it's just the convection to the south dissipating and the convection to the north remaining providing an illusion that makes it look like it's starting to move more northerly.

Quoting CybrTeddy:
TWO out, no change and virtually the same writing.

it this noted that so no point in posting it

Atlantic Tropical Weather Outlook


000
ABNT20 KNHC 152338
TWOAT

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT MON AUG 15 2011

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
STORM GERT...LOCATED ABOUT 135 MILES EAST-NORTHEAST OF BERMUDA.

A TROPICAL WAVE IN THE VICINITY OF THE LESSER ANTILLES IS PRODUCING
A LARGE AREA OF DISORGANIZED CLOUDINESS AND SHOWERS. THERE ARE NO
SIGNS OF A SURFACE CIRCULATION AT THIS TIME AND PRESSURES ARE NOT
FALLING SIGNIFICANTLY OVER THE AREA. ENVIRONMENTAL CONDITIONS ARE
EXPECTED TO BE MARGINALLY CONDUCIVE FOR DEVELOPMENT OF THIS SYSTEM
DURING THE NEXT COUPLE OF AS IT MOVES WESTWARD AT 15 TO 20 MPH OVER
THE CARIBBEAN SEA. THIS SYSTEM HAS A LOW CHANCE...20 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER PASCH


Only at 20%? Really?

Quoting Levi32:


Um yeah it would. It means that a Cat 4 counts for even more points over a Cat 3 than the ACE would have given it.

Yes, I responded too fast.

Quoting stormpetrol:


Needless to say I totally agree though convection is not as strong, it has expanded in size and organized significantly since this morning in my opinion.

Still at 20%.

Quoting HurricaneDean07:
Thinking the piece that split from gert South of Cuba, will be mentioned as 10% at the next TWO, Maybe...

ULL is just to the SW of this AOI.

Quoting kmanislander:
Apart from having expanded in aerial coverage I see no difference between 93L when it received 20% from the NHC and now. I would go for 20% and wait to see if the convection starts to rebuild before stepping it up to 30% later. Might as well join in the ratings game LOL

IMO if 93L wants to develop it has to slow down which typically happens as it gets closer to the Western Caribbean.

Quoting kmanislander:
Apart from having expanded in aerial coverage I see no difference between 93L when it received 20% from the NHC and now. I would go for 20% and wait to see if the convection starts to rebuild before stepping it up to 30% later. Might as well join in the ratings game LOL

I always lacked skill with Lets Make a Deal.

Wrong curtain for me..

LoL

SHOWER AND THUNDERSTORM ACTIVITY HAS BECOME A LITTLE MORE
CONCENTRATED AND SLIGHTLY BETTER ORGANIZED IN ASSOCIATION WITH A
BROAD AREA OF LOW PRESSURE CENTERED ABOUT 400 MILES SOUTHEAST OF
ACAPULCO MEXICO. ENVIRONMENTAL CONDITIONS ARE FORECAST TO BE
MARGINALLY CONDUCIVE FOR THE DEVELOPMENT OF THIS DISTURBANCE...AND
A TROPICAL DEPRESSION COULD FORM DURING THE NEXT DAY OR TWO.
THIS SYSTEM HAS A MEDIUM CHANCE...50 PERCENT...OF BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

Quoting usa777:
Curios as to how they calculated the ACE value of a storm back in 1899?

They have best-track data back through 1851 for Atlantic storms. They calculated the ACE based on the estimated 6-hourly intensities for that storm. Needless to say, the accuracy of the data for those storms back when observations were sparse is in question.

Quoting kmanislander:
Apart from having expanded in aerial coverage I see no difference between 93L when it received 20% from the NHC and now. I would go for 20% and wait to see if the convection starts to rebuild before stepping it up to 30% later. Might as well join in the ratings game LOL

You nailed it, and I really suspect that's why the % stayed the same.

Quoting usa777:
Curios as to how they calculated the ACE value of a storm back in 1899?

It doesn't require a satellite or anything like that. All they need is lifespan and intensity at 6 hour intervals, and they have that for just about if not every storm in the database.

Quoting usa777:
Curios as to how they calculated the ACE value of a storm back in 1899?

Using the HURDAT file for maximum sustained winds. HURDAT goes back to 1851.

Quoting Levi32:


You have mail. I have no idea how experienced you are with linux so I tried to include detailed instructions. It takes me 10 seconds to do it, so if it's difficult at first to give the correct inputs, just practice a couple times and I think you will find that it's pretty easy. Perhaps you will find a way to make my script even simpler than I currently have it. I'm fairly new to BASH.

Thank you so much. The instructions are comprehensive but brief and straightforward as is the script. You'd make a good Prof.

I'll be sure to send you a copy of changes, if any, I make for my purposes.

Quoting clwstmchasr:


IMO if 93L wants to develop it has to slow down which typically happens as it gets closer to the Western Caribbean.

Yes, I commented on that last night. 15 to 20 mph through the eastern Caribbean is not conducive to a wave trying to develop.

Quoting presslord:
Way cool space news Link

They finally announced COTS-2 and COTS-3 combining? That's excellent news!! Commercial crew here we come!

Quoting LowerCal:

Thank you so much. The instructions are comprehensive but brief and straightforward as is the script. You'd make a good Prof.

I'll be sure to send you a copy of changes, if any, I make for my purposes.

Glad it works! I forgot to mention that you have to have curl and imagemagick installed for it to work, but I think a lot of distributions carry those by default.

Quoting Levi32:


It quantitatively changes it though. It means that a Cat 4 counts for even more points over a Cat 3 than the ACE would have given it. I guess there is a debate over which exponential function describes the power best.

Strictly speaking, the kinetic energy is the velocity squared as you know. Using a different power of velocity, is just giving some arbitrary assignment in the difference between a cat. 1 and a cat. 5 say. To me, the ACE is fine, but the size of the storm must also be included. Since the ACE is so crude, why can't they at least modify so it is the product of the max. velocity squared and the average radius of the hurricane strength wind field squared? That's not hard to change.

Quoting tropicfreak:

Atlantic Tropical Weather Outlook


000
ABNT20 KNHC 152338
TWOAT

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT MON AUG 15 2011

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
STORM GERT...LOCATED ABOUT 135 MILES EAST-NORTHEAST OF BERMUDA.

A TROPICAL WAVE IN THE VICINITY OF THE LESSER ANTILLES IS PRODUCING
A LARGE AREA OF DISORGANIZED CLOUDINESS AND SHOWERS. THERE ARE NO
SIGNS OF A SURFACE CIRCULATION AT THIS TIME AND PRESSURES ARE NOT
FALLING SIGNIFICANTLY OVER THE AREA. ENVIRONMENTAL CONDITIONS ARE
EXPECTED TO BE MARGINALLY CONDUCIVE FOR DEVELOPMENT OF THIS SYSTEM
DURING THE NEXT COUPLE OF AS IT MOVES WESTWARD AT 15 TO 20 MPH OVER
THE CARIBBEAN SEA. THIS SYSTEM HAS A LOW CHANCE...20 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER PASCH


Only at 20%? Really?

they said the same thing from the 2pm two so there not relly a point in posting the two they said the same thing

Lovely weather in New Zeleand, ya know global warming.

Freak snowfall has NZ reeling

Will be interesting when recon goes out tomorrow….If warranted.

Ooooooooh weeeee,

The Western Carribean is the Sweet Spot downstream.

Lawdy,Lawd,Lawd,,,,

Quoting barbamz:

Sometimes I think, nearly *everyone* on this blog has some personal experience with Germany, lol. Nice ...
Now I'm heading to the pillows, nite all, have fun with 93L.

Was stationed in Wiesbaden for 4 years (at what was Lindsey Air Station) back in the late 70's/early 80's.

Best day trip was to drive up the Rhine to St Goar/St Gorhausen, and down the other side (stopping off to take a side trip to the top of The Lorelei).

Beautiful country.

Quoting SouthDadeFish:
You nailed it, and I really suspect that's why the % stayed the same.

By any objective standard 20% is the right number.

East pacific outlook:

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
500 PM PDT MON AUG 15 2011

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON NEWLY FORMED
TROPICAL DEPRESSION SIX-E...LOCATED ABOUT 1655 MILES WEST-SOUTHWEST
OF THE SOUTHERN TIP OF BAJA CALIFORNIA.

SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A BROAD AREA OF LOW
PRESSURE LOCATED ABOUT 600 MILES SOUTHWEST OF MANZANILLO MEXICO
HAVE CHANGED LITTLE IN ORGANIZATION THIS AFTERNOON. STRONG
UPPER-LEVEL WINDS ARE LIKELY TO INHIBIT THE DEVELOPMENT OF THIS
DISTURBANCE DURING THE NEXT COUPLE OF DAYS. THIS SYSTEM HAS A LOW
CHANCE...10 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD AT 10 TO 15 MPH.

SHOWER AND THUNDERSTORM ACTIVITY HAS BECOME A LITTLE MORE
CONCENTRATED AND SLIGHTLY BETTER ORGANIZED IN ASSOCIATION WITH A
BROAD AREA OF LOW PRESSURE CENTERED ABOUT 400 MILES SOUTHEAST OF
ACAPULCO MEXICO. ENVIRONMENTAL CONDITIONS ARE FORECAST TO BE
MARGINALLY CONDUCIVE FOR THE DEVELOPMENT OF THIS DISTURBANCE...AND
A TROPICAL DEPRESSION COULD FORM DURING THE NEXT DAY OR TWO.
THIS SYSTEM HAS A MEDIUM CHANCE...50 PERCENT...OF BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

Quoting Patrap:
Ooooooooh weeeee,

The Western Carribean is the Sweet Spot downstream.

Lawdy,Lawd,Lawd,,,,

I dont like that circle around Grand Cayman though Lol

I don't know the statistics or if any research paper has been written on the "speed" issue but the norm formation speed on waves-to TD's or Storms is usually 10-12 MPH. Any faster and there are problems with consolidation and we have seen many fall apart when convection pulls ahead (or is sheered ahead) of a viable COC tying to get vertically stacked.....15-20 MPH for 93L at the moment is just too fast for significant development.

Quoting robj144:


Strictly speaking, the kinetic energy is the velocity squared as you know. Using a different power of velocity, is just giving some arbitrary assignment in the difference between a cat. 1 and a cat. 5 say. To me, the ACE is fine, but the size of the storm must also be included. Since the ACE is so crude, why can't they at least modify so it is the product of the max. velocity squared and the average radius of the hurricane strength wind field squared? That's not hard to change.

I think the best explanation is because without recon data, it is difficult to accurately determine the radius of hurricane force winds, TS force winds, etc. Satellite data can only give us so much...

Also, averaging the radius implies there are no asymmetries, which is often not the case.

Quoting robj144:


Strictly speaking, the kinetic energy is the velocity squared as you know. Using a different power of velocity, is just giving some arbitrary assignment in the difference between a cat. 1 and a cat. 5 say. To me, the ACE is fine, but the size of the storm must also be included. Since the ACE is so crude, why can't they at least modify so it is the product of the max. velocity squared and the average radius of the hurricane strength wind field squared? That's not hard to change.

Well the whole cubed thing may have something to do with the changing size of the wind radii in a typical stronger hurricane, which may nudge it away from just a square function. The mass is changing too, which changes kinetic energy. I have not read up much on the PDI though.

No it doesn't seem like the ACE would be hard to change, but I'm afraid that at the top levels of just about any agency, changing anything from a standard is very difficult.

Quoting Levi32:
A more colorful and telling comparison:

Ciriaco spent exactly 11 days as a major hurricane. Ivan did also, with the exception of three 6-hour increments where he was a Cat 2. Ciriaco spent a short time as a Cat 4, while Ivan was a Cat 4 or Cat 5 for the majority of his lifetime.

Ciriaco:



Ivan:

All good points. Nevertheless, San Ciriaco was a storm as many as 10 days longer than Ivan. It also had quite a number of those days at hurricane strength.

Somebody else commented about the extratropical phase, but it seems the second hurricane phase was actually one of the few documented instances of a hurricane strike on the Azores.

Pretty interesting storm.