A Gulf of Mexico and an Eastern Atlantic Disturbance Worth Watching

By: Dr. Jeff Masters , 1:53 PM GMT on July 06, 2013

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A tropical disturbance (designated 94L by NHC on Friday) is over the Western Gulf of Mexico, and is headed north towards the Texas/Louisiana coast at 5 - 10 mph. Satellite loops show a modest area of disorganized heavy thunderstorm activity that has been steadily growing this morning. Wind shear has fallen to the moderate range, 10 - 20 knots, since Friday, and the lower wind shear is likely responsible for the increase in thunderstorm activity. A trough of low pressure over the Western Gulf of Mexico is pumping dry air into the west side of 94L, interfering with development. The disturbance should move inland by Sunday morning, bringing heavy rains of 1 - 3" along the Upper Texas and Western Louisiana coasts through Monday morning. None of the reliable forecast models predict that the disturbance will develop, and the disturbance has only a day over water with marginal conditions for development. In their 8 am EDT July 6 Tropical Weather Outlook, NHC gave the disturbance a 20% chance of developing into a tropical depression or tropical storm by Monday.


Figure 1. The Saturday morning NHC Tropical Weather Outlook shows two "Invests" worth watching: 94L over the Gulf of Mexico (area 1), and 95L over the Eastern Atlantic (area 2.) Both were given 20% chances of developing by Monday. Image credit: NHC.

Cape Verdes tropical wave 95L
As we approach mid-July, it's time to begin turning our attention to tropical waves coming off the coast of Africa. We have our first such system worthy of attention today, a tropical wave designated 95L over the Eastern Atlantic near 8°N 33°W, about 800 miles southwest of the Cape Verde Islands. Satellite loops show a modest area of heavy thunderstorms that is showing a moderate amount of spin. Wind shear is moderate, 10 - 20 knots, and ocean temperatures are warm, 28°C. The 8 am EDT Saturday forecast from the SHIPS model predicted that 95L would encounter cooler waters of 27.5°C over the weekend as it headed west to west-northwest at 15 - 20 mph. Wind shear is expected to remain moderate though Monday, which may allow for some additional organization. However, 95L is embedded in a very large area of dry air associated with the Saharan Air Layer (SAL), and July African waves typically have considerable trouble getting organized in the very dry air of the SAL. The disturbance could arrive in the Lesser Antilles Islands as early as Tuesday. A band a strong upper-level winds associated with the subtropical jet stream is expected to be over the northern islands at that time, and if 95L has penetrated as far north as 15°N latitude by that time, it will have to face very high wind shear of 30+ knots. But if 95L stays farther to the south, wind shear should be lower, giving the storm a better chance of development. None of the reliable forecast models predict that 95L will develop. In their 8 am EDT July 6 Tropical Weather Outlook, NHC gave the disturbance a 20% chance of developing into a tropical depression or tropical storm by Monday.


Figure 2. MODIS image of 95L taken at approximately 11 am EDT Saturday, July 6, 2013. Image credit: NASA.

Elsewhere in the tropics
A large upper-level cold-cored low pressure system a few hundred miles north of Puerto Rico will move west over the next dew days, arriving in the Bahamas by Sunday and South Florida by Tuesday. The models do not show that this low will will acquire a surface circulation, and there is only minimal heavy thunderstorm activity associated with it.

In the Eastern Pacific, Tropical Storm Erick is brushing the southwestern coast of Mexico, and is expected to intensify into a Category 1 hurricane on Saturday afternoon. Erick will bring heavy rains of 3 - 5 inches to Southwest Mexico, but the core of the storm is currently expected to remain just offshore. Erick will likely weaken to a tropical storm on Monday, when it will pass just south of Baja.

Cool San Francisco time-lapse fog video
Videographer Simon Christen has created a spectacular 4-minute time-lapse video of fog rushing in past the Golden Gate Bridge into San Francisco. He writes: ""Adrift" is a love letter to the fog of the San Francisco Bay Area. I chased it for over two years to capture the magical interaction between the soft mist, the ridges of the California coast and the iconic Golden Gate Bridge. This is where “Adrift” was born. The weather conditions have to be just right for the fog to glide over the hills and under the bridge. I developed a system for trying to guess when to make the drive out to shoot, which involved checking the weather forecast, satellite images and webcams multiple times a day. For about 2 years, if the weather looked promising, I would set my alarm to 5am, recheck the webcams, and then set off on the 45-minute drive to the Marin Headlands. I spent many mornings hiking in the dark to only find that the fog was too high, too low, or already gone by the time I got there. Luckily, once in a while the conditions would be perfect and I was able to capture something really special. Adrift is a collection of my favorite shots from these excursions into the ridges of the Marin Headlands."


Video 1. Adrift from Simon Christen on Vimeo.

Jeff Masters

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Will the ULL soon moving across Bahamas and eventually into the GOM have any effect on the messy convection in the GOM?
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1053. Patrap
Member Since: July 3, 2005 Posts: 421 Comments: 127701


this is the mid level water vapor




and upper
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Quoting 860. Tazmanian:
we may have a vary powerfull hurricane in a few days

That is defiantly one of the possibilities.
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Quoting 1045. stormpetrol:



I see spin
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Should be 50-60% at 8 pm est.
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Track guidance is in a fairly good agreement:

Member Since: July 21, 2011 Posts: 83 Comments: 7167
Quoting 1034. dfwstormwatch:
18Z HWRF has a weak t.s/t.d passing through the Central Caribbean , currently at 90 hours out.
You have images from raleighwx, if you do then post them up?
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Quoting 1019. AllBoardedUp:
Oh, okay, I thought he might be saying I'm JFV. Hell, I've been on this sight since '05, with the same user name.
We know it's u, boarded.

Quoting 1022. hurricanes2018:
read this!!
It's gotta loosen up that hold on the ITCZ before it hits Guyana and Surinam, though... geez... it's weird to be watching something this low in the ATL... most seasons we would have already dismissed this.

BTW, anybody have a better look @ the AEW that's coming off the African coast right now? TVM

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Not bad...

Member Since: July 21, 2011 Posts: 83 Comments: 7167
Quoting 1037. HurricaneAndre:
Small system rapidly get stronger.

And are also more succeptable to unfavorable conditions. Stale mate my friend.
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Quoting 1024. Grothar:


Of course its movement would be almost due west for now. There is nothing influencing it. By the time it approaches the islands it will begin responding by moving WNW. All the models agree on this motion, they begin to diverge at this point, which is nothing unusual this far out. What is unusual is that all models currently bring it to the Northern Antilles.


Am I the only one thinking it's rare for all the models to be in such tight agreement this early? And the track does resemble Isabel as someone noted way back.
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Quoting 1028. Grothar:


It has, but aren't you surprised to see something that far out this early?

Considering how vigorous and active the African Monsoon has been, Not really. 92L could've been declared a storm back in June, and it was out in the Central Atlantic. This is probably one of the Strongest Train of AEW's to get going in the Atlantic Basin since 2005, It only hints where the Season is headed from here. I definitely can see we are vulnerable to many, some intense Hurricanes that will track all the way across the Atlantic. The season is a force to be reckoned with, steering pattern, MDR activity, and atmospheric pattern are in position to make this season one of the worst ones since 2004 and 2005. And some may disagree with me and say otherwise, but I will say it Boldly. Be prepared, this season is going to bring some terror and nightmares to a lot of coastal areas. June and July mean nothing, the real meat of the season is yet to come, and boy, when we get into it, there's no stopping.

Anyway, that's all I got to say. Be back later.
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Quoting 1024. Grothar:


Of course its movement would be almost due west for now. There is nothing influencing it. By the time it approaches the islands it will begin responding by moving WNW. All the models agree on this motion, they begin to diverge at this point, which is nothing unusual this far out. What is unusual is that all models currently bring it to the Northern Antilles.


Agreed. I think the high pressure is too great above it along with the easterly (somewhat southeasterly) flow, and it'll track further west into the central Caribbean. Moving way too fast to find the northern Antilles I think.
Member Since: July 9, 2006 Posts: 184 Comments: 29596
Quoting 1037. HurricaneAndre:
Small system rapidly get stronger.


If the conditions are favorable. Likewise, small systems get significantly weaker if just one thing goes against them, say the dry SAL that is just off to the north of 95L.
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Small system rapidly get stronger.
Member Since: June 11, 2013 Posts: 19 Comments: 2581
Quoting 1026. AllBoardedUp:
Hey Cat5hit, when I first saw your user name I thought it said something else which I can't repeat on here. lol
Lol I thought the exact same thing. 
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Quoting 1025. unknowncomic:
This path its probably curtains for this one.


Lots of model runs to come......
Member Since: September 23, 2005 Posts: 14 Comments: 10933
18Z HWRF has a weak t.s/t.d passing through the Central Caribbean , currently at 90 hours out.
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Quoting 989. MississippiWx:


HWRF had a major upgrade and is supposed to be a lot more accurate this season. We will see about that...
Looks like everybody got some nu shoes... guess they wanna get invited to the party....

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95L is small....
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Daytime storms firing to the left of me and tropical rain to my right.



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1030. FOREX
Quoting 1025. unknowncomic:
This path its probably curtains for this one.


I'm learning. What do you mean by your comment?
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Quoting 1019. AllBoardedUp:
Oh, okay, I thought he might be saying I'm JFV. Hell, I've been on this sight since '05, with the same user name.

Yeah, I didnt mean to offend you, Ive been lurking on the blog since 07/08 and decided to join in 2010, was just saying that he has so many accounts it's really difficult to access who's who, and if he still is around. He definetely is, just hope the mods will just IP ban him already. It's gone on long enough.
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1028. Grothar
Quoting 1021. TylerStanfield:

It has waned a little on the South side, but overall it has maintained organization through DMIN. DMAX should really help it get going...


It has, but aren't you surprised to see something that far out this early?
Member Since: July 17, 2009 Posts: 69 Comments: 25514
Quoting 1014. Camille33:

40% coming at 8pm.
I think you are right!!
Member Since: March 12, 2013 Posts: 8 Comments: 13862
Hey Cat5hit, when I first saw your user name I thought it said something else which I can't repeat on here. lol
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Quoting 999. nrtiwlnvragn:


Track appears about the same but the 2013 version is not as enthusiastic as the 2012 version for intensity.






This path its probably curtains for this one.
Member Since: August 2, 2011 Posts: 0 Comments: 1789
1024. Grothar
Quoting 1011. moonlightcowboy:


95L's motion now and for some time yet is anything but north, especially considering its forward speed.


Of course its movement would be almost due west for now. There is nothing influencing it. By the time it approaches the islands it will begin responding by moving WNW. All the models agree on this motion, they begin to diverge at this point, which is nothing unusual this far out. What is unusual is that all models currently bring it to the Northern Antilles.
Member Since: July 17, 2009 Posts: 69 Comments: 25514
1023. whitewabit (Mod)
Quoting 1016. Cat5hit:


Is JFV and Golden Shower Boy the same person?

And how does the My Little Pony shower curtain play into this?


Lets get back to the discussion of the blog ..

Thank you ..
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read this!!
Member Since: March 12, 2013 Posts: 8 Comments: 13862
Quoting 1017. Grothar:
First time yellow has shown up in 95L which means very cold cloud tops. A percentage upgrade will be warranted with this one.


It has waned a little on the South side, but overall it has maintained organization through DMIN. DMAX should really help it get going...
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Quoting 992. washingtonian115:
Looks like 95L wants to pay a visit to Florida.I suspect it wants to tour the Sunshine state?

No thanks we've had our share of tourists.
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Quoting 1008. washingtonian115:
He's talking about JFV which some members seem to be obsessed with.Why don't they just IP ban him for good.Anywho back to weather.
Oh, okay, I thought he might be saying I'm JFV. Hell, I've been on this sight since '05, with the same user name.
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Quoting 1017. Grothar:
First time yellow has shown up in 95L which means very cold cloud tops. A percentage upgrade will be warranted with this one.


Yep but looking at windsat looks like llc is perhaps exposed,but it definitely looking better.
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1017. Grothar
First time yellow has shown up in 95L which means very cold cloud tops. A percentage upgrade will be warranted with this one.

Member Since: July 17, 2009 Posts: 69 Comments: 25514
Windsat had a great pass

Pretty close to depression status...

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Quoting 1013. hurricanes2018:
its up invest 95L

40% coming at 8pm.
Member Since: July 2, 2013 Posts: 0 Comments: 1436
its up invest 95L
Member Since: March 12, 2013 Posts: 8 Comments: 13862
Quoting 1006. TropicalAnalystwx13:

I thought the HWRF wasn't getting its upgrade until July 15?


The upgraded version has been running on WCOSS.
Member Since: September 23, 2005 Posts: 14 Comments: 10933
Quoting 1005. Grothar:



The HWRF will have a more northerly bias to 95L bringing it over or North of Puerto Rico and the DR in 5 days. The other models will be slightly south of that.


95L's motion now and for some time yet is anything but north, especially considering its forward speed.
Member Since: July 9, 2006 Posts: 184 Comments: 29596
1010. Patrap
Floater - Infrared Channel 2 Loop

click image for Loop

Member Since: July 3, 2005 Posts: 421 Comments: 127701
I sure hope we here in the Galveston area get some rain out of 94l. My new sod planted back in April is fading fast.
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Quoting 1002. AllBoardedUp:
Huh?
He's talking about JFV which some members seem to be obsessed with.Why don't they just IP ban him for good.Anywho back to weather.
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SSD Floater is up for 95L.

Link
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Quoting 989. MississippiWx:


HWRF had a major upgrade and is supposed to be a lot more accurate this season. We will see about that...

I thought the HWRF wasn't getting its upgrade until July 15?
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1005. Grothar
Quoting 989. MississippiWx:


HWRF had a major upgrade and is supposed to be a lot more accurate this season. We will see about that...



The HWRF will have a more northerly bias to 95L bringing it over or North of Puerto Rico and the DR in 5 days. The other models will be slightly south of that.
Member Since: July 17, 2009 Posts: 69 Comments: 25514
1004. Dakster
Quoting 932. Grothar:


So my buddy John Hopes to play in Hebert's box tomorrow.

(Happy now?)
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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.