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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2204. Patrap


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Quoting 2201. wunderkidcayman:

Maybe maybe not


There is 2 llc...one under the main tstms the other exposed,it's an optical illusion.
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Things look favorable until about 60 W.....after that it looks like lots of Shear unless the storm develops it's own upper level anticyclone as it moves through it
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Quoting 2198. nrtiwlnvragn:
NRL Monterey ASCAT A solution, not even close to a closed circulation..........










Link

Maybe maybe not

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New graphic out from NHC

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2199. Patrap

AL952013 - INVEST

Storm Relative 1km Geostationary Visible Imagery


click image for loop


to ZOOM, click on the animated image

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NRL Monterey ASCAT A solution, not even close to a closed circulation..........










Link
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Quoting 2194. weatherlover94:



I don't guess we will know what the future holds for it until we get the cone and intensity forecast from the NHC. In the 8:00 am update they said conditions are EXPECTED to be favorable

In the short term (1-2 days out), not the long term.
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Quoting 2191. beell:


a little pop-up over the first rejected swirl.

If that was an rejected swirl

Quoting 2192. Tazmanian:



by looking at that it looks like 95L center have refourm too the S and under the t-storms


if it was exposs then i dont think it would have a T # of 2.0 then


07/1145 UTC 9.1N 41.1W T2.0/2.0 95L -- Atlantic



some in two think about

Maybe

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Quoting 2183. Tropicsweatherpr:
Quoting 2183. Tropicsweatherpr:
This really reminds me of Irene and Emily of 2011 when the first advisory have them cross Hispañola and then a landfall in Florida.
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Quoting 2185. trHUrrIXC5MMX:


I'm fairly sure the storm is going to become a cyclone... But still unsure what it'll do afterwards, lots of factors ahead of the storm

High pressure ridge, it's strength
How strong the storm gets
Land interaction, especially Hispaniola, and how strong it gets there and how strong it leaves
Depending on how strong it leaves, that could determine the path, a weaker storm heads more westwards. Stronger storm more northwards, like I said, the high pressure ridge matters here
Then you must deal with dry air, winds hear and how strong they are

See? Too many factors in forecasting, there are others I don't mention



I don't guess we will know what the future holds for it until we get the cone and intensity forecast from the NHC. In the 8:00 am update they said conditions are EXPECTED to be favorable
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Quoting 2188. ackee:
I wonder if 95L is just clearing the path for that wave that just came off Africa guess we know in a few days

95L may develop and sweep out the condition for the next one
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Quoting 2176. hydrus:



by looking at that it looks like 95L center have refourm too the S and under the t-storms


if it was exposs then i dont think it would have a T # of 2.0 then


07/1145 UTC 9.1N 41.1W T2.0/2.0 95L -- Atlantic



some in two think about
Member Since: May 21, 2006 Posts: 5091 Comments: 114759
2191. beell
Quoting 2176. hydrus:


a little pop-up over the first rejected swirl.
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Quoting 2180. allancalderini:
If it gains latitude it will run into Sal.

It'll get latitude slowly... It's not going to be moving straight north as it organizes.
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2188. ackee
I wonder if 95L is just clearing the path for that wave that just came off Africa guess we know in a few days
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2187. Patrap
Quoting 2181. redwagon:
Quoting 2162. Patrap:

I been in the right place. But it must have been the wrong time. I'd of said the right thing. But I must have used the wrong line. I been in the right trip. But I must ..... RIP? 94L


Dr. John, yeah you rite', or Mac to us Local's.
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Quoting 2170. SLU:


You're right .. the SAL to the north is backing away. The problem will be when the SAL to its west gets drawn into the large circulation.

Yeah no that to its W will get pushed as well

Quoting 2174. stormwatcherCI:
95L seems to be pushing the dry air out of it's way and moistening it's forward path.

Yep

Quoting 2175. ackee:
agree the system need to gain some latitude also the center relocating further south means this system will going through the Caribbean if it does not develop before it reach the eastern Caribbean I don't see it developing until it reach the western Caribbean if it survive south america

Yep

I don't think the LLC will relocate I think the convection will rebuild and shift back over the LLC
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Quoting 2172. weatherlover94:
.

it looks like it is trying to build up its Eastern side. I am going to say Tropical Cyclone by tomorrow some time I am predicting 50% on the next TWO at 2:00 pm and maybe 60 0r 70 at 2:00 am....the million dollar question remains...after it develops what happens to it ? Does it get sheared apart or become our first Hurricane ?


I'm fairly sure the storm is going to become a cyclone... But still unsure what it'll do afterwards, lots of factors ahead of the storm

High pressure ridge, it's strength
How strong the storm gets
Land interaction, especially Hispaniola, and how strong it gets there and how strong it leaves
Depending on how strong it leaves, that could determine the path, a weaker storm heads more westwards. Stronger storm more northwards, like I said, the high pressure ridge matters here
Then you must deal with dry air, winds hear and how strong they are

See? Too many factors in forecasting, there are others I don't mention
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Quoting 2129. Grothar:
I better start my checklist.




Step by step, frame by frame...Niagara Falls!
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2182. FOREX
Quoting 2180. allancalderini:
If it gains latitude it will run into Sal.


I hope it stalls.
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Quoting 2162. Patrap:

I been in the right place. But it must have been the wrong time. I'd of said the right thing. But I must have used the wrong line. I been in the right trip. But I must ..... RIP? 94L
Member Since: August 4, 2007 Posts: 0 Comments: 3180
Quoting 2154. weatherlover94:
If 95 L doesn't start to gain some Lattitude it going to run right into South America
Quoting 2154. weatherlover94:
If 95 L doesn't start to gain some Lattitude it going to run right into South America
If it gains latitude it will run into Sal.
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Quoting 2169. washingtonian115:
Unfortunately with that strong ridge in place that seems it doesn't want to break down soon it has two options.East coast of gulf.


I know, but wishes are free. My Gran taught me if you're going to dream, dream big. *G*
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2178. Patrap
...is a cute one'


AL952013 - INVEST

Enhanced Infrared (IR) Imagery (4 km Mercator)

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Quoting 2173. stormchaser19:


It's dry air or dusty SAL....Wishcaster are you!!!


let's not fight
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2176. hydrus
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2175. ackee
Quoting 2135. SLU:
Based on the latest loops, it seems that 95L's center is relocating further south along its elongated trough under the MLC near 8n 42w. This would give it a better chance for survival since it would be more vertically stacked and the center would be closer to the deepest convection.

agree the system need to gain some latitude also the center relocating further south means this system will going through the Caribbean if it does not develop before it reach the eastern Caribbean I don't see it developing until it reach the western Caribbean if it survive south america
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Quoting 2168. mynameispaul:
95L seems to be pushing the dry air out of it's way and moistening it's forward path.
Member Since: October 9, 2008 Posts: 0 Comments: 8272
Quoting 2163. Camille33:

lol there is no sal it is moisture seperated blanket.Wishcaster.


It's dry air or dusty SAL....Wishcaster are you!!!If the mods are here this is the time to ban!!!
Member Since: June 20, 2012 Posts: 0 Comments: 2150
Quoting 2164. trHUrrIXC5MMX:

As the storm organizes it gets latitude... Don't worry, it still has time and space
.

it looks like it is trying to build up its Eastern side. I am going to say Tropical Cyclone by tomorrow some time I am predicting 50% on the next TWO at 2:00 pm and maybe 60 0r 70 at 2:00 am....the million dollar question remains...after it develops what happens to it ? Does it get sheared apart or become our first Hurricane ?
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Quoting 2137. Camille33:

This is a td or what is going on?



It needs a closed low level circulation to be called a TD.

There is conflicting information on CSU website, because some tools have it ranked as high as T3.8 already, but the max official winds are still only 35mph.

In spite of having circulation, you can tell from Dvorak and Funktop that this thing is not significantly developed yet at this time.

Coldest cloud tops are barely -60C, but it needs widespread -60C and isolated -80C to really be on the path to a TS...
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2170. SLU
Quoting 2167. wunderkidcayman:

SaL ain't on him and look again 95Ls convection is pushing the SAL away


You're right .. the SAL to the north is backing away. The problem will be when the SAL to its west gets drawn into the large circulation.
Member Since: July 13, 2006 Posts: 12 Comments: 4889
Quoting 2165. aislinnpaps:


If we're going to wish it somewhere, let's wish it out to sea. Don't want to wish it on anyone.
Unfortunately with that strong ridge in place that seems it doesn't want to break down soon it has two options.East coast of gulf.
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Quoting 2158. stormchaser19:
The SAL covering him,some development are not anticipated maybe in 24-36 when the SALT decrease.

SaL ain't on him and look again 95Ls convection is pushing the SAL away
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Quoting 2138. Patrap:


..all, my, Invest's, own a low rider...


take a little trip, take a little trip, take
Member Since: August 4, 2007 Posts: 0 Comments: 3180
Quoting 2159. washingtonian115:
I want this to go into the gulf.Sorry I know this sounds selfish but I really don't want another storm.Just got finished dealing with flood problems and trees in my yard have been weaken.So any strong gust and they will go toppling over.


If we're going to wish it somewhere, let's wish it out to sea. Don't want to wish it on anyone.
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Quoting 2154. weatherlover94:
If 95 L doesn't start to gain some Lattitude it going to run right into South America

As the storm organizes it gets latitude... Don't worry, it still has time and space
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Quoting 2158. stormchaser19:
The SAL covering him,some development are not anticipated maybe in 24-36 when the SALT decrease.

lol there is no sal it is moisture seperated blanket.Wishcaster.
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2162. Patrap
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Quoting 2124. GTstormChaserCaleb:
Off topic: WKC or Stormpetrol do they still sell the Tortuga Rum Cake in the Caymans?
They do, and it is amazing.
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Correct me if Im wrong but wasn't Charley in 2004 about as small as 95L is now when it first developed ?
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I want this to go into the gulf.Sorry I know this sounds selfish but I really don't want another storm.Just got finished dealing with flood problems and trees in my yard have been weaken.So any strong gust and they will go toppling over.
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The SAL covering him,some development are not anticipated maybe in 24-36 when the SAL decrease.
Member Since: June 20, 2012 Posts: 0 Comments: 2150
I'll leave you with this....

Fresh view of 95L from NASA



COC in the NE corner under the feeder band/umbilical to ITCZ

Larger view here
Member Since: September 30, 2007 Posts: 9 Comments: 15932
95L will be around for a few days, it is vigourous African wave those never seem to die off quietly. Don't expect it to just to dissapate anytime soon.
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Quoting 2150. Camille33:
I have seen lots of eventual big storms with exposed llc, this happens a lot of times.


I have seen a lot of nothing storms with the same thing

its a watch and wait, 95L has its work cut out for it honestly
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If 95 L doesn't start to gain some Lattitude it going to run right into South America
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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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