Invest 90L in the Tropical Atlantic

By: Dr. Jeff Masters , 29. heinäkuuta 2010 klo 23:35 (GMT)

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Hi everybody, Dr. Rob Carver filling in for Dr. Masters while he's on vacation.

NHC has designated an area of thunderstorms in the tropical Atlantic as Invest 90L (8.5 N, 30.0 W). Microwave remote sensing suggests there are some decent storms in 90L, peak rain rates were around 1-2 inches/hours. According to CIMMS wind-shear analyses 90L is under 10-15 knots of shear with positive divergence aloft. The former isn't quite favorable for further development as it will ventilate the system, but the latter is favorable because it will aid in removing outflow from the storms. There's also a broad area of weak shear to the west and northwest of 90L's current position. Looking at the 500 mb height patterns, the steering currents for 90L are to the WNW, which will move it into the area of weaker shear and get it further away from the equator. This is important because if 90L stays south, it will have trouble developing a circulation. It will have a better chance of becoming a tropical cyclone once it goes north of 10N. The Saharan Air Layer is lurking just to the north of 90L. A WNW track would keep 90L out of the SAL, which is good for development.


Fig. 1 IR Satellite Composite of 90L taken at 540 PM EDT.


Fig. 2 Saharan Air Layer analysis courtesy of CIMMS.

Model Forecasts and Climatology
The 12Z Canadian model moves 90L to the WNW and develops tropical-storm force winds at the surface. The 12Z and 18Z GFS runs are less aggressive in intensifying 90L and adjusts the track so that 90L is moving to the WNW. Based on the run-to-run consistency, previous model verification (i.e. the Canadian model's tendency to overdo intensification), general synoptic pattern, I favor the GFS solution for now. Looking at climatology based on research done by Dr. Bob Hart at Florida State University, none of the tropical cyclones that passed within 1 degree of 90L's current position has ever made landfall. We'll have to keep an eye on this storm, but I don't think it's likely to be a major threat to the Caribbean or US.

Update
Dr. Masters says he'll update this blog entry with a discussion of the Moscow heatwaves later tonight.

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438. Skyepony (Mod)
30. heinäkuuta 2010 klo 03:15 (GMT)
Truecajan~ It was kinda funny..
Member Since: 10.08.2005 Posts: 156 Comments: 36173
436. HaboobsRsweet
30. heinäkuuta 2010 klo 02:31 (GMT)
All of the models have it too far north...just watch. Each day the tracks will slowly work their way south. Just like they always do. and the model runs are junk now. Takes about 24 hours for them to get a grip on the situation and even then without a closed low they will still struggle.
Member Since: 20.05.2009 Posts: 0 Comments: 1640
435. truecajun
30. heinäkuuta 2010 klo 02:17 (GMT)
meant to quote hurricanedancer on 10 in october, not myself. are we really that behind on the numbers?? i mean usually they don't ramp up until right about now, right?
Member Since: 24.08.2006 Posts: 0 Comments: 1867
434. truecajun
30. heinäkuuta 2010 klo 02:13 (GMT)
oops. sorry
Member Since: 24.08.2006 Posts: 0 Comments: 1867
432. truecajun
30. heinäkuuta 2010 klo 02:12 (GMT)
Quoting truecajun:


i know. i'm just joking because so many people have been upset about the GW discussions. i've tried to calm a few really angry ones by reminding them that it's the docs blog adn it's weather related, so we have to deal.

it's just funny because for the past 2 days all they wanted was something to watch and the blog to update. finally it did due to the wave - something to watch. then bam, he ends the update with GW. but you are right, it is weather news, that's why we can't get mad about it. it's still pretty funny though.
Member Since: 24.08.2006 Posts: 0 Comments: 1867
431. scott39
30. heinäkuuta 2010 klo 02:09 (GMT)
The heat is building and building in the Atlantic! A TCs job is to release it! 90L isnt going to realease it all by itself and the Pacific isnt going to help much either! There is plenty of show to come this season! This is one thing ive learned on here that is really simple! Im hoping this helps the bloggers that are constantly downcasting this season! Remember---Heat= release =TC
Member Since: 13.06.2009 Posts: 0 Comments: 6706
430. earthlydragonfly
30. heinäkuuta 2010 klo 02:08 (GMT)
Quoting hurrkat05:
EARTHLYDRAGONFLY APPARENTLY YOU JUST DONT READ MY POSTS ...I WILL SAY THIS FOR THE 4TH TIME TONIGHT THE REASON THE TROPICS ARE DEAD IS THE AAL=DRY AIR THIS DRY AIR HAS SPERAD ALL THE WAY TO FLORIDA...NO SYSTEM CAN DEVELOP THAT WAS EVIDENT WITH BONNIE WHEN SHE WAS SWALLOWED BY DRY AIR...THE WESTERLY SHEAR WILL BE VERY ACTIVE THIS YEAR BECAUSE I BELIEVE WE ARE IN A NEUTRAL YEAR NOT AND LA NINA ONE...OK THATS WHY I THINK ITS GOING TO BE AND AVERAGE HURRICANE SEASON AND LOOK FOR DR GRAY ON AUG 4 TO DROP HIS PREDITION AT LEAST 4 STORMS HE DOESNT WANT TO LOOK LIKE A FOOL...I HOPE THIS ANSWERS YOUR QUESTION..


Dude I said lets see what you got. Post a blog with some Science... Lets see it...
Member Since: 1.07.2005 Posts: 10 Comments: 1681
428. SouthALWX
30. heinäkuuta 2010 klo 02:05 (GMT)
Quoting KEEPEROFTHEGATE:
in other news ice is still melting


Doesnt that happen .. in summer ...every year?
Member Since: 27.08.2008 Posts: 0 Comments: 1497
427. NoNamePub
30. heinäkuuta 2010 klo 02:04 (GMT)
Quoting Tazmanian:
the W PAC hurricane season is a bust


WAHOO - Thanks TAZ - Am I safe in C PAC?
Member Since: 13.07.2007 Posts: 0 Comments: 518
426. HurricaneSwirl
30. heinäkuuta 2010 klo 02:03 (GMT)
Quoting hurrkat05:
ok hurricane swirl one more time my reasons why i said a slow season are you listening...
1 SHEAR
2 SAL = DRY AIR...


lol are you listening? I just said that's what you do. And that is direct contradiction because

1:


Anomalies are at or below average throughout the atlantic

2. You cannot apply July, the peak of SAL, to the rest of the hurricane season, especially in terms of SAL.

Only reason I'm posting this is for others, because it's obvious there is no hope in reasoning with trolls, and that they just win by getting responses like this out of them.
Member Since: 7.07.2008 Posts: 2 Comments: 3237
424. louisianaboy444
30. heinäkuuta 2010 klo 02:02 (GMT)
Quoting futuremet:
Does anyone have access to the Saharan Air Layer or Aerosol forecasts?


Link
Member Since: 29.08.2006 Posts: 22 Comments: 1339
423. louisianaboy444
30. heinäkuuta 2010 klo 02:01 (GMT)
Link

This is a good link...I commonly use this to aid me in my forecasts... Alot of useful links here
Member Since: 29.08.2006 Posts: 22 Comments: 1339
421. MiamiHurricanes09
30. heinäkuuta 2010 klo 02:01 (GMT)
NEW BLOG!!!
Member Since: 2.09.2009 Posts: 130 Comments: 21032
420. earthlydragonfly
30. heinäkuuta 2010 klo 02:00 (GMT)
Quoting hurrkat05:
guys you need to calm down and quit yelling if someone uses caps so the hell what i see people use them all the time...you guys are just going to have to realize this is going to be a very slow hurricane season so live with it...quit acting like a bunch of losers and blaming it on the NHC and DR MASTERS...grow up man whatever happens you sure are not going to change it so live with it and grow up..
Quoting hurrkat05:
guys you need to calm down and quit yelling if someone uses caps so the hell what i see people use them all the time...you guys are just going to have to realize this is going to be a very slow hurricane season so live with it...quit acting like a bunch of losers and blaming it on the NHC and DR MASTERS...grow up man whatever happens you sure are not going to change it so live with it and grow up..


So you are so Sure of the bust or season that will not produce what so many others have forecast.. (might I add, they have backed their theory with research and blogs with the supporting information) Where is your blog and research that supports your scientific prediction? If you have none then POOF... Make one and I'll read it... I just think you have nothing but the whole 13 year old.... "because I told you so" theory.... I stopped listening to that over 30 years ago when I was promoted to High school from middle school.... So grow a pair and back up your position with some research dude.
Member Since: 1.07.2005 Posts: 10 Comments: 1681
419. Tazmanian
30. heinäkuuta 2010 klo 01:59 (GMT)
the W PAC hurricane season is a bust
Member Since: 21.05.2006 Posts: 5089 Comments: 114075
418. HurricaneSwirl
30. heinäkuuta 2010 klo 01:59 (GMT)
Quoting HurricaneSwirl:


No they are not actually.

It is 1.1 degrees away by using the Pythagorean Theorum and the Distance formula

d = sqrt of (xsub2 - xsub1)^2 + (ysub2 - ysub1)^2

31.3-32.1= -.8
-.8^2=.64

8.2-9.0= -.8
-.8^2=.64

.64 + .64 = 1.28

The square root of 1.28 is 1.13 (doesn't look right, but check yourself, it is)

d=1.13

Well that was a lot to type up over something so minute lol



It's very easy to count the distance between two points that are at the same latitude or longitude, but when they are diagonal from each other you will need to use this to figure out the exact distance between the two points.

Most people probably already know but that was just a quick google search to find nice site for teaching those who are curious.
Member Since: 7.07.2008 Posts: 2 Comments: 3237
415. SLU
30. heinäkuuta 2010 klo 01:57 (GMT)
Quoting thelmores:


I typically ignore models which don't initialize in the right location, or right direction..... in this case extrap and the models don't jive.....

But the GFDL and HWRF, and many other dynamic models don't seem to do well at this stage of cyclogenesis........


Got that right.
Member Since: 13.07.2006 Posts: 12 Comments: 4734
414. watchingnva
30. heinäkuuta 2010 klo 01:57 (GMT)
Quoting hurrkat05:
tesxas hurricane i predicteed 13 named storms at the beginning of the season that's for from being a slow season so what are you talking about lol..


a joke.
Member Since: 7.09.2005 Posts: 7 Comments: 1475
413. truecajun
30. heinäkuuta 2010 klo 01:56 (GMT)
Quoting louisianaboy444:
My Evening Weather Analysis hope you enjoy!

Link


thanks for the update. good future considerations.
Member Since: 24.08.2006 Posts: 0 Comments: 1867
411. HurricaneSwirl
30. heinäkuuta 2010 klo 01:55 (GMT)
Quoting hurrkat05:
tesxas hurricane i predicteed 13 named storms at the beginning of the season that's for from being a slow season so what are you talking about lol..


1. Refer to post 400.

2. Your forecast isn't why you're a troll. It's the way you present it. You just go "Ahaha I'm always right this will be slow haha nothing will develop there" You don't provide any reasoning to it. Occasionally you will say "high shear shutting down the tropics" but it is a direct contradiction to the evidence that supports below normal shear throughout the majority of the basin. Just trying to calmly reason with you. If you just ignore it and throw it to the side like usual, then it's hopeless. Although in your eyes it is probably a success, because at that point it's obvious you do this stuff on purpose.
Member Since: 7.07.2008 Posts: 2 Comments: 3237
410. TexasHurricane
30. heinäkuuta 2010 klo 01:55 (GMT)
Quoting hurrkat05:
texas hurricane what i meant and you didnt read down further by slo i meant it will take almost the whole season to get to 13 that's what im talking about slow man...


ok, we will see I guess. I'm not taking any guesses as to how many, because I have no clue.
Member Since: 2.07.2009 Posts: 0 Comments: 2811
409. bappit
30. heinäkuuta 2010 klo 01:55 (GMT)
Quoting pipelines:
I'm not going to agree or disagree with Dr. Carver about the likely hood of 90L affecting land, but I am going to question the logic of the basis of his opinion on this subject.

I don't have the information he does concerning what has formed within 1 degree of 90L but I'm going to go out on a limb and make the (pretty safe) assumption that there has been only a handful of tropical cyclones to have passed said location. While averages are usually fairly accurate when pulling from a large data pool, they are grossly inaccurate when pooling from a very small one.

Also, he is going by cyclones that were already formed and designated as such within 1 degree of 90L, there is a huge tracking difference between an ITCZ embedded wave and a formed cyclone at this latitude.

Again, not disagreeing with Dr. Carver, but I just don't see this particular opinion being a valid one due to the data set it is based on having little pertinence to 90L

Awwwww, go ahead and disagree. You make good points. Carver doesn't.
Member Since: 18.05.2006 Posts: 10 Comments: 5563
407. caneswatch
30. heinäkuuta 2010 klo 01:53 (GMT)
Quoting hurrkat05:
btktex im very calm im worrying about you guys killing yourselves...i told you guys the dust and westerly shear will do a number on this season...so deal with it ..we will have a few maybe 3 in august september could be a little busier we will just have to wait and see...but guys that predicted 18+ can throw those down the tubes..even 13 i predicted im starting to be concerned we wont get to that...we will see...
POOF
Member Since: 8.10.2008 Posts: 14 Comments: 4553
404. help4u
30. heinäkuuta 2010 klo 01:51 (GMT)
I started drinking a coke at 5:00,full of ice, at 9:50 the ice is almost gone.I think the end is nearer than we all think.Maybe the end before midnight.
Member Since: 18.09.2006 Posts: 0 Comments: 1257
403. nrtiwlnvragn
30. heinäkuuta 2010 klo 01:51 (GMT)
Quoting Levi32:


If there was an archive of model runs on previous storms somewhere I'd give you everything you need. The US hurricane models consistently have a poleward bias, and a bad one.

And for the record, I'm not anti-NOAA.


It varies from year to year and by location. As a whole in the Atlantic basin last year the GFDL (GHMI) and the HWRF were biased SouthEast. Other years, yes they have shown a NorthWest bias, but so do the other models. Model bias is reported each year in NHC verification reports.

deg/nm bias forecast hour

Model ID 12 24 36 48 72 96 120
GHMI 164/016 156/025 156/034 162/040 171/026 156/072 155/152
HWFI 105/007 086/016 118/021 136/031 174/055 180/149 185/270
Member Since: 23.09.2005 Posts: 13 Comments: 10472
402. BDAwx
30. heinäkuuta 2010 klo 01:50 (GMT)
Quoting hurrkat05:
tesxas hurricane i predicteed 13 named storms at the beginning of the season that's for from being a slow season so what are you talking about lol..


13 named storms is not a slow season.
Member Since: 3.08.2009 Posts: 51 Comments: 525
401. futuremet
30. heinäkuuta 2010 klo 01:49 (GMT)
Does anyone have access to the Saharan Air Layer or Aerosol forecasts?
Member Since: 19.07.2008 Posts: 43 Comments: 4051
400. TexasHurricane
30. heinäkuuta 2010 klo 01:49 (GMT)
Quoting hurrkat05:
tesxas hurricane i predicteed 13 named storms at the beginning of the season that's for from being a slow season so what are you talking about lol..


This...

Quoting hurrkat05:
guys you need to calm down and quit yelling if someone uses caps so the hell what i see people use them all the time...you guys are just going to have to realize this is going to be a very slow hurricane season so live with it...quit acting like a bunch of losers and blaming it on the NHC and DR MASTERS...grow up man whatever happens you sure are not going to change it so live with it and grow up..
Member Since: 2.07.2009 Posts: 0 Comments: 2811
398. weathermancer
30. heinäkuuta 2010 klo 01:49 (GMT)
Quoting hurrkat05:
btktex im very calm im worrying about you guys killing yourselves...i told you guys the dust and westerly shear will do a number on this season...so deal with it ..we will have a few maybe 3 in august september could be a little busier we will just have to wait and see...but guys that predicted 18+ can throw those down the tubes..even 13 i predicted im starting to be concerned we wont get to that...we will see...


I can see 10 is just October
Member Since: 29.08.2009 Posts: 12 Comments: 482
397. truecajun
30. heinäkuuta 2010 klo 01:48 (GMT)
Quoting Skyepony:


Oh come on.. it's so bad~ there has been over 2000, mostly highly intoxicated people, that have drowned while trying to cool themselves off in the last two months there. I know heat waves aren't the most exciting but if that's not some crazy heat wave record worthy of mention~ what is??


i know. i'm just joking because so many people have been upset about the GW discussions. i've tried to calm a few really angry ones by reminding them that it's the docs blog adn it's weather related, so we have to deal.

it's just funny because for the past 2 days all they wanted was something to watch and the blog to update. finally it did due to the wave - something to watch. then bam, he ends the update with GW. but you are right, it is weather news, that's why we can't get mad about it. it's still pretty funny though.
Member Since: 24.08.2006 Posts: 0 Comments: 1867
395. Levi32
30. heinäkuuta 2010 klo 01:48 (GMT)
Quoting Drakoen:


Archive


So for starters, we have one of the early HWRF runs on Ike in 2008:



We had the GFDL and GFS taking Alex this year into Louisiana:



And you know the story with Bonnie when the GFDL and HWRF took it into north Florida or Georgia, which was utterly ridiculous.

There are a few more examples but I don't have the time to dig around more. The point is they usually have a bias especially early in the storms's lifetime. I only pulled out the ones I could remember off the top of my head from the last couple years with big names.

If that's anti-NOAA.....lol so be it. Our US models have a problem. Period. They do better when they are locked on with the rest of the group and the situation becomes abundantly clear. The same thing is true with the CFS. The European models trash our's most of the time in a lot of things. It's just a simple fact.
Member Since: 24.11.2005 Posts: 628 Comments: 26460
394. futuremet
30. heinäkuuta 2010 klo 01:46 (GMT)
As 90L detaches from the ITCZ [18Z Surface Analysis], it will become more self-sufficient by producing its surface convergence. Once this happens, a well-defined upper level anticyclone will form over it [18Z GFS].
Member Since: 19.07.2008 Posts: 43 Comments: 4051
392. thelmores
30. heinäkuuta 2010 klo 01:45 (GMT)
Quoting SLU:


the system's heading is WSW or about 255 degrees yet still the models fail to recognise that initial southward component and they take system due WNW from the onset. The BAM suite does take into consideration this initial motion a little better and they show a westward movement for a day or so before they begin to lift the system northwards which makes more sense at least from a meteorological standpoint.


I typically ignore models which don't initialize in the right location, or right direction..... in this case extrap and the models don't jive.....

But the GFDL and HWRF, and many other dynamic models don't seem to do well at this stage of cyclogenesis........
Member Since: 8.09.2005 Posts: 0 Comments: 3788
391. Walshy
30. heinäkuuta 2010 klo 01:45 (GMT)
I love this blog.


Member Since: 17.05.2009 Posts: 2 Comments: 904
390. KEEPEROFTHEGATE (Mod)
30. heinäkuuta 2010 klo 01:44 (GMT)
in other news ice is still melting

Member Since: 15.07.2006 Posts: 165 Comments: 52390
389. CaneWarning
30. heinäkuuta 2010 klo 01:44 (GMT)
Quoting hurrkat05:
guys you need to calm down and quit yelling if someone uses caps so the hell what i see people use them all the time...you guys are just going to have to realize this is going to be a very slow hurricane season so live with it...quit acting like a bunch of losers and blaming it on the NHC and DR MASTERS...grow up man whatever happens you sure are not going to change it so live with it and grow up..


LOL
Member Since: 26.04.2009 Posts: 3 Comments: 3667
388. Skyepony (Mod)
30. heinäkuuta 2010 klo 01:43 (GMT)
Quoting truecajun:


he also wrote "Dr. Masters says he'll update this blog entry with a discussion of the Moscow heatwaves later tonight"

BOOOOOOO!



Oh come on.. it's so bad~ there has been over 2000, mostly highly intoxicated people, that have drowned while trying to cool themselves off in the last two months there. I know heat waves aren't the most exciting but if that's not some crazy heat wave record worthy of mention~ what is??
Member Since: 10.08.2005 Posts: 156 Comments: 36173

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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