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African Tropical Wave 98L a Marginal Threat to Develop

By: Dr. Jeff Masters , 3:38 PM GMT on July 22, 2013

A strong and well-organized tropical wave moved off the coast of Africa on Monday, and has been designated 98L by NHC. This disturbance is headed west at 10 - 15 mph, and is under a moderate 10 - 15 knots of wind shear. A large amount of dry air lies to the north and west of 98L, and will likely interfere with development. The SHIPS model predicts that wind shear will stay in the moderate range through Thursday, then rise to the high range, 20 - 30 knots, on Friday and Saturday. Ocean temperature are warm off the coast of Africa (27 - 28°C,), but will cool to 25 - 26°C on Tuesday through Thursday, a temperature that is quite marginal for development. None of the computer models predict that 98L will develop, not even the usually aggressive Canadian (CMC) model. In their 8 am EDT Monday Tropical Weather Outlook, NHC gave 98L a 10% chance of developing into a tropical cyclone by Wednesday. 98L should maintain a west to west-northwest track through the week, and may bring heavy rains and gusty winds to the northern Lesser Antilles Islands beginning on Saturday night.


Figure 1. Satellite image of 98L off the coast of Africa taken at 8 am EDT Monday July 22, 2013, with a satellite analysis of where dry air is, as well. A large amount of dry air lies to the north and west of 98L, and will likely interfere with development. Image credit: University of Wisconsin CIMSS and NOAA/HRD.


Figure 2. MODIS satellite image of 98L taken at approximately 8 am EDT July 22, 2013. Image credit: NASA.

Jeff Masters


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

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1793. unknowncomic
9:28 AM GMT on July 24, 2013
The model intensity must be based on land contact in the Caribbean. No land contact means much stronger.
Member Since: December 31, 1969 Posts: Comments:
1792. GTstormChaserCaleb
4:17 PM GMT on July 23, 2013
PWAT values are good way to measure the amount of precipitation in the atmosphere, not much in the way of the dry air here on this run:

Member Since: December 31, 1969 Posts: Comments:
1791. Grothar
2:34 PM GMT on July 23, 2013
Quoting 1748. GeoffreyWPB:


You are a good friend to all. :)


Thanks for the tip on clicking on the right. This long wait is getting annoying.
Member Since: December 31, 1969 Posts: Comments:
1790. Patrap
2:24 PM GMT on July 23, 2013
Its only 7:30 almost in SF with the server so the issue may take a spell to fix.

Member Since: December 31, 1969 Posts: Comments:
1789. WunderAlertBot (Admin)
2:23 PM GMT on July 23, 2013
JeffMasters has created a new entry.
1788. hu2007
2:21 PM GMT on July 23, 2013
time to work. later guys for more updates :)
Member Since: December 31, 1969 Posts: Comments:
1787. GatorWX
2:21 PM GMT on July 23, 2013
Quoting 1778. 69Viking:


I kid you not I've had well over 20" at my house since the beginning of July. I wish I would have kept detail records to give the exact amount, it's staggering for sure!


I wouldn't say it's a staggering amount here in sw fl, but there has been a lot of training storms dumping 3-6 inches in a very short time in isolated areas. There has also been a lot of storms moving in off the gulf which is somewhat unusual although not for this early in the summer. We went about 20 days with rain every single day and about 15-20 inches in that period. Conditions have become a bitter stable and usual in the last week. We certainly haven't had many sea breeze induced tstms like we normally get, but that seems to be changing. Between my area, yours and especially the Carolina's and NE, much rain has fallen on the east.
Member Since: December 31, 1969 Posts: Comments:
1786. cat6band
2:19 PM GMT on July 23, 2013
Quoting 1775. weathermanwannabe:
Here is the nice original EUMET African visible satt link shot (again) for the wave showing the evolution through this morning; much slower than the NHC link which tends to run very fast:

Link



Very cool....
Member Since: December 31, 1969 Posts: Comments:
1785. JRRP
2:17 PM GMT on July 23, 2013
Member Since: December 31, 1969 Posts: Comments:
1784. weatherlover94
2:16 PM GMT on July 23, 2013
be back on later.
Member Since: December 31, 1969 Posts: Comments:
1783. Autistic2
2:15 PM GMT on July 23, 2013
Quoting 1776. washingtonian115:
I wouldn't get excited about 98L if I were you.


Excited, not exactly but it is something, besides a naked ULL to watch!
Member Since: December 31, 1969 Posts: Comments:
1782. wunderkidcayman
2:15 PM GMT on July 23, 2013
Quoting 1773. EyEtoEyE:
Good morning, Patrap , the center looks like , it's at 12.5 N and 23.5 W ? Let me know , what you see?

12.2N 23.5W that is clear seen on vis sat images
Member Since: December 31, 1969 Posts: Comments:
1781. Patrap
2:15 PM GMT on July 23, 2013


Member Since: December 31, 1969 Posts: Comments:
1780. 62901IL
2:14 PM GMT on July 23, 2013
Quoting 1779. Autistic2:
F5 taking 75 seconds. Did some one kill or injure the blog today?

Happening to me too!
Member Since: December 31, 1969 Posts: Comments:
1779. Autistic2
2:12 PM GMT on July 23, 2013
F5 taking 75 seconds. Did some one kill or injure the blog today?
Member Since: December 31, 1969 Posts: Comments:
1778. 69Viking
2:12 PM GMT on July 23, 2013
Quoting 1737. GatorWX:


I think we'll see many top ten wettest summers for lots of folks. I almost want to think this is perhaps more of a harbinger than Chantal was. The amount of precipitately water over the eastern US and surrounding water has seemed very high to me. I can imagine what effect it would have on a strong system.


I kid you not I've had well over 20" at my house since the beginning of July. I wish I would have kept detailed records to give the exact amount, it's staggering for sure!
Member Since: December 31, 1969 Posts: Comments:
1777. GatorWX
2:11 PM GMT on July 23, 2013
Quoting 1766. TimSoCal:
Satellite presentation looks like a TD or even a TS. Wonder why it hasn't been classified as such yet.


Convection is warming. They like persistence. Also the path takes it in a much less conducive environment. Today is its window in the short term I think.
Member Since: December 31, 1969 Posts: Comments:
1776. washingtonian115
2:11 PM GMT on July 23, 2013
Quoting 1774. Autistic2:
Good Morning all,

Doing well today!

Well now, NHC says we have something worth watching in the MDR, season starting for real?
I wouldn't get excited about 98L if I were you.
Member Since: December 31, 1969 Posts: Comments:
1775. weathermanwannabe
2:10 PM GMT on July 23, 2013
Here is the nice original EUMET African visible satt link shot (again) for the wave showing the evolution through this morning; much slower than the NHC link which tends to run very fast:

Link

Member Since: December 31, 1969 Posts: Comments:
1774. Autistic2
2:09 PM GMT on July 23, 2013
Good Morning all,

Doing well today!

Well now, NHC says we have something worth watching in the MDR, season starting for real?
Member Since: December 31, 1969 Posts: Comments:
1773. EyEtoEyE
2:09 PM GMT on July 23, 2013
Good morning, Patrap , the center looks like , it's at 12.5 N and 23.5 W ? Let me know , what you see?
Member Since: December 31, 1969 Posts: Comments:
1772. hu2007
2:08 PM GMT on July 23, 2013
hi everyone ,the invest 98 look like is getting there but not yet, if you all watch closely you will see on the visible image that the wave/ low is struggling with drier air from the east and some dry easterlie shear from africa, but as it move farther west from africa the system should improve developing but not for long cause there will be an upper trof by friday near the island that as the future dorian moves wnw it may not kill dorian if the storm pass south of 25 and ever get strong like a moderate t.s or stronger if is stay weak it may well avoid the trof by the island passing beneath and move more west as it develops close to the western carribean still a lot could happen but this my thinking after seeing the trend and the maps you guys posted :)
Member Since: December 31, 1969 Posts: Comments:
1771. wunderkidcayman
2:08 PM GMT on July 23, 2013
Quoting 1758. GatorWX:


It's not overly hard to discern where the center is and west it goes.


yep

Quoting 1762. Patrap:
If 12 N was Hwy 1, it's running right down the centerline seems this am.

Nice envelope too.


yes
Member Since: December 31, 1969 Posts: Comments:
1770. Tazmanian
2:07 PM GMT on July 23, 2013
Quoting 1766. TimSoCal:
Satellite presentation looks like a TD or even a TS. Wonder why it hasn't been classified as such yet.




it has a long was too go be for 98L is a TD or TS and its window it closeing
Member Since: December 31, 1969 Posts: Comments:
1769. weatherlover94
2:06 PM GMT on July 23, 2013
the 12Z models are in. Some show nothing but steady strengthening. Some show it strengthening then slow weakening....others show strengthening then meeting it's death.....very hard to say right now.
Member Since: December 31, 1969 Posts: Comments:
1768. 62901IL
2:06 PM GMT on July 23, 2013
Under a slight risk for storms today.
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1767. Tazmanian
2:06 PM GMT on July 23, 2013
Quoting 1753. Camille33:
I had to delete about 18 malware in my avast antivirus.There may be a virus infecting the blog,check on this please.




they can check on any thing if you have a virus its likey your laptop and not the blog
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1766. TimSoCal
2:06 PM GMT on July 23, 2013
Satellite presentation looks like a TD or even a TS. Wonder why it hasn't been classified as such yet.
Member Since: December 31, 1969 Posts: Comments:
1765. Patrap
2:05 PM GMT on July 23, 2013
Check dis out.

7/22 PROPHECY *Nostradamus* Quatrain 41
Nostradamus
Century 2 Quatrain 41

The great star for seven days will burn
A cloud will make two suns appear
The big mastiff will howl all night
When a great Pope changes his territory




The Pope arrived in Brazil yesterday

A Son was Born in England

..back to your er, Stormy thingeee.

..ewww, weeee, ewww
Member Since: December 31, 1969 Posts: Comments:
1764. GatorWX
2:05 PM GMT on July 23, 2013
Quoting 1762. Patrap:
If 12 N was Hwy 1, it's running right down the centerline seems this am.

Nice envelope too.



Indeed, especially west of the center. A nice shield perhaps, or one that'll disappear this afternoon. We'll see. Time marches on.
Member Since: December 31, 1969 Posts: Comments:
1763. LargoFl
2:04 PM GMT on July 23, 2013
THIS HAZARDOUS WEATHER OUTLOOK IS FOR WEST CENTRAL AND SOUTHWEST
FLORIDA.

.DAY ONE...TODAY AND TONIGHT.

...THUNDERSTORM IMPACT...
SHOWERS AND STORMS LOOK TO ARRIVE ALONG THE COAST TO THE NORTH OF
TAMPA BAY DURING THE MORNING HOURS. SOME SOUTHWARD PROGRESS IS
LIKELY AND STORMS MAY DEVELOP FAR ENOUGH SOUTH TO REACH THE I-4
CORRIDOR OR EVEN SARASOTA BEFORE MIDDAY. OTHERWISE A FEW MORE
SCATTERED STORMS WILL DEVELOP THROUGH THE AFTERNOON AND EVENING
ALONG THE SEA-BREEZE MOVING INLAND TO THE SOUTH OF TAMPA BAY. NO
SIGNIFICANT SEVERE WEATHER IS ANTICIPATED...HOWEVER AS IS USUAL
DURING THE SUMMER...A FEW STORMS ARE LIKELY TO BECOME STRONG WITH
GUSTY WINDS AND FREQUENT LIGHTNING.

...FLOOD IMPACT...
SOME AREAS MAY RECEIVE LOCALLY HEAVY RAIN TODAY RESULTING IN MINOR
URBAN AND STREAM FLOODING. SOME LOCAL RIVERS ARE ALSO NEAR OR
ABOVE FLOOD STAGE.
Member Since: December 31, 1969 Posts: Comments:
1762. Patrap
2:02 PM GMT on July 23, 2013
If 12 N was Hwy 1, it's running right down the centerline seems this am.

Nice envelope too.

Member Since: December 31, 1969 Posts: Comments:
1761. LargoFl
2:01 PM GMT on July 23, 2013
from daytona northward,stay alert to your local warnings,stay safe..
Member Since: December 31, 1969 Posts: Comments:
1760. Hurricanes305
2:01 PM GMT on July 23, 2013
Quoting 1739. GeoffreyWPB:


The page will load quickly if you click on someones "blog post" on the Community Activity to the right.
Tried restarting and clearing cookies in google chrome and clicking on someone's blog post it still loads over 2 minutes. My also reset may internet connection. 
Edit: after testing out the speed by post this comment it took about 1.40 secs
Member Since: December 31, 1969 Posts: Comments:
1759. Patrap
2:00 PM GMT on July 23, 2013
But,

..her moves looked good, a touch of desperation...
Member Since: December 31, 1969 Posts: Comments:
1758. GatorWX
2:00 PM GMT on July 23, 2013
Quoting 1751. Patrap:


It's not overly hard to discern where the center is and west it goes.

Member Since: December 31, 1969 Posts: Comments:
1757. Patrap
1:59 PM GMT on July 23, 2013
Morn...

I havent really looked close yet, still in coming alive mode here.
Member Since: December 31, 1969 Posts: Comments:
1756. Patrap
1:58 PM GMT on July 23, 2013
Member Since: December 31, 1969 Posts: Comments:
1755. GTstormChaserCaleb
1:57 PM GMT on July 23, 2013
Quoting 1751. Patrap:
Good morning Pat...is that a wobble to the north I see? :D
Member Since: December 31, 1969 Posts: Comments:
1754. LargoFl
1:57 PM GMT on July 23, 2013
Member Since: December 31, 1969 Posts: Comments:
1753. Camille33
1:55 PM GMT on July 23, 2013
I had to delete about 18 malware in my avast antivirus.There may be a virus infecting the blog,check on this please.
Member Since: December 31, 1969 Posts: Comments:
1752. GTstormChaserCaleb
1:55 PM GMT on July 23, 2013
850 mb.



700 mb.



500 mb.

Member Since: December 31, 1969 Posts: Comments:
1751. Patrap
1:53 PM GMT on July 23, 2013
Member Since: December 31, 1969 Posts: Comments:
1750. Grothar
1:50 PM GMT on July 23, 2013
Quoting 1747. Patrap:
Make sure your own page has not defaulted to Higher comments.


If you look on the bottom left, it seems to get hung up on the tropicaltidbits link.
Member Since: December 31, 1969 Posts: Comments:
1749. islander101010
1:50 PM GMT on July 23, 2013
this is like blogging back in the ninties slow,
Member Since: December 31, 1969 Posts: Comments:
1748. GeoffreyWPB
1:50 PM GMT on July 23, 2013
Quoting 1746. Grothar:


Suppose I don't like them?


You are a good friend to all. :)
Member Since: December 31, 1969 Posts: Comments:
1747. Patrap
1:48 PM GMT on July 23, 2013
Make sure your own page has not defaulted to Higher comments.
Member Since: December 31, 1969 Posts: Comments:
1746. Grothar
1:47 PM GMT on July 23, 2013
Quoting 1739. GeoffreyWPB:


The page will load quickly if you click on someones "blog post" on the Community Activity to the right.


Suppose I don't like them?
Member Since: December 31, 1969 Posts: Comments:
1745. GTstormChaserCaleb
1:46 PM GMT on July 23, 2013
Starting from the West Coast to the Atlantic: Ridge, Trough, Ridge, Trough, Ridge. The Ridge in the Atlantic and the Ridge in the Central Plains looks to want to cause a squeeze play on that front on the East Coast.

Day 7:



Member Since: December 31, 1969 Posts: Comments:
1744. LargoFl
1:46 PM GMT on July 23, 2013
Member Since: December 31, 1969 Posts: Comments:
1743. Patrap
1:46 PM GMT on July 23, 2013
No, I dont tink datz it at all. We would of had a presser on something like that fer sure
Member Since: December 31, 1969 Posts: Comments:

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Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather