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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2104. ackee
what will become of 95L ?


A TS
B TD
C OPEN WAVE
D Dissipate


Member Since: Posts: Comments:
Quoting 2098. MAweatherboy1:

From 48 hours on SHIPS is saying 20-30kts of shear for 95L with only marginal moisture to work with. That combined with its fast forward motion would likely prevent development if it verified. If it can avoid the higher shear though it could at least become a TD. I am thinking it goes south of what the current models think.

Well looking at the shear maps its got 5-10kt shear ahead it band to its W is keeping the dry air at bay for now and I believe it's forward speed should drop down soon so it should keep it going and if any development it will happen slower than expected and I think you're right it will travel S of what the models show
Member Since: June 13, 2009 Posts: 2 Comments: 12147
I want 95L to stay away from here.If its more weaker then it'll probably track through the caribbean and may eventually turn northward into the gulf.But that's wishful thinking.
Member Since: August 14, 2010 Posts: 10 Comments: 17075
Based on this loop would have to agree there is an exposed low level swirl.
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The mere fact that these models want to turn it more towards the WNW would not only imply a change in direction, but a slow down in speed.
Member Since: June 30, 2013 Posts: 12 Comments: 8428
Link

A lot of the Ensembles take the storm just north of Hispaniola and if that is the case and as the storm in what ever form it's in turns toward the Unites States could be a nasty one. If the storm Gets tangled up in the Islands like many models are suggesting it could be nothing more than an open wave and hit Florida as a rain event.....we will have to wait and see
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Quoting 2083. stormchaser19:
the forecast is saying for the increase for the trade winds, as 95l moves west-northwest definitely, bad scenario for him....

From 48 hours on SHIPS is saying 20-30kts of shear for 95L with only marginal moisture to work with. That combined with its fast forward motion would likely prevent development if it verified. If it can avoid the higher shear though it could at least become a TD. I am thinking it goes south of what the current models think.
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Quoting 2093. DDR:
Bracing for rains 95L in Trinidad,no way this goes north of 14N by 61w.

Yeah I think you're right

Quoting 2094. Hurricanes101:
95L will not develop unless it slows down, forecasts are mixed on whether or not this is actually going to happen

I think it should do so soon
Member Since: June 13, 2009 Posts: 2 Comments: 12147
Quoting 2085. weatherlover94:
Guys how do you change your profile picture ? I have done several things with it but I can't get it to change
Your talking to the expert.Click on your pic then go t upload photos which is in the upper right side of your screen.Then after click the browse button to get pictures from your computer.Or press my photos modify if you have some uploaded to this site and press "my primary photo"
Member Since: August 14, 2010 Posts: 10 Comments: 17075

 
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95L will not develop unless it slows down, forecasts are mixed on whether or not this is actually going to happen
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2093. DDR
Bracing for rains 95L in Trinidad,no way this goes north of 14N by 61w.
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What happened to 94L? I blinked and it's gone-sure was hoping for some rain in S. TX.
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Quoting Neapolitan:
Looks to be. There are a number of videos on YouTube showing the event.

Nice image.


DANG!! That's like snow.
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Quoting 2082. AussieStorm:


I have a feeling this could be an east coast system.



I have a feeling you are right. My best guess right now is any where from Myrtle Beach SC north to Virginia Beach VA
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Quoting 2079. yonzabam:
95L is small, dry and moving too quickly. I don't expect much from it.

It's growing, not close to dry and soon going to slow down a bit so stop being a downcaster

Quoting 2080. stormpetrol:


Sad! Ithink we'll have a TD by early evening or tonight.

Maybe and maybe not till tomorrow
Member Since: June 13, 2009 Posts: 2 Comments: 12147
Quoting 2082. AussieStorm:


I have a feeling this could be an east coast system.


Yep. Anywhere between Nicaragua and Newfoundland.
Member Since: July 20, 2008 Posts: 0 Comments: 2927
Back in my lurking days in 2009 there was a tropical wave that people were rooting to develop..it was by Africa and I think it was 99L? but it then got shredded to pieces by the shear and people had a funeral for it.lol.
Member Since: August 14, 2010 Posts: 10 Comments: 17075
LLC? img src="http://rammb.cira.colostate.edu/ramsdis/onlin e/images/latest/tropical/tropical_ge_1km_center_relative_vis_floater.gif">
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Guys how do you change your profile picture ? I have done several things with it but I can't get it to change
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Quoting 2075. CybrTeddy:


There's a circulation, however it appears to be only half-closed. It's better than it was yesterday, however it still has a lot of work to do. Not bad though for something hauling at 24mph.

Yes Teddy

Quoting 2077. weatherlover94:
95L needs to build convection on the eastern side

If you take a close look at the satellite loop you can see its already starting two spots on the S part of the LLC and another on E side of circulation
Member Since: June 13, 2009 Posts: 2 Comments: 12147
The forecast is saying for the increase for the trade winds, as 95l moves west-northwest definitely, bad scenario for him....
Member Since: June 20, 2012 Posts: 0 Comments: 2159
Quoting weatherlover94:
A lot of the GFS ensembles want to take it to either Florida or the Carolina's


I have a feeling this could be an east coast system.
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Erick down to Tropical Storm.

TROPICAL STORM ERICK DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL EP052013
800 AM PDT SUN JUL 07 2013

SATELLITE IMAGES INDICATE THAT ERICK IS WEAKENING. THE CENTRAL DENSE
OVERCAST HAS BECOME LESS ORGANIZED WITH WARMING CLOUD TOPS AND NO
SIGNS OF AN EYE IN THE LATEST MICROWAVE IMAGES. THE INITIAL
INTENSITY IS REDUCED TO 60 KT...WHICH IS A BLEND OF THE
TAFB/SAB/CIMSS DVORAK ESTIMATES. IT SEEMS LIKELY THAT ERICK HAS
PEAKED IN INTENSITY WITH THE CYCLONE NOW CROSSING OVER COOLER
WATERS. A GRADUAL DECREASE IN WIND SPEED IS FORECAST...A BIT BELOW
THE INTENSITY CONSENSUS AND THE PREVIOUS NHC PREDICTION. THE
CYCLONE SHOULD BECOME POST-TROPICAL IN A COUPLE OF DAYS WHEN THE
SYSTEM MOVES OVER SUB-22C WATER...IF NOT SOONER.

THE INITIAL MOTION ESTIMATE REMAINS 310/9. A MID-LEVEL RIDGE OVER
NORTHWESTERN MEXICO AND THE SOUTHWESTERN UNITED STATES IS EXPECTED
TO HOLD FIRM FOR THE NEXT FEW DAYS...CAUSING ERICK TO MOVE
NORTHWESTWARD...THEN WEST-NORTHWESTWARD TO WESTWARD AS IT BECOMES A
MORE SHALLOW SYSTEM. MOST OF THE GLOBAL MODELS SHOW THE STORM
PASSING SOUTH OF BAJA CALIFORNIA SUR...BUT CLOSE ENOUGH TO BRING
TROPICAL-STORM-FORCE WINDS TO THE COAST. THE LATEST NHC FORECAST
IS BASICALLY AN UPDATE OF THE PREVIOUS ONE...BETWEEN THE FLORIDA
STATE SUPERENSEMBLE AND THE DYNAMICAL MODEL CONSENSUS.

BECAUSE ERICK IS MOVING AWAY FROM MAINLAND MEXICO...THE TROPICAL
STORM WARNING FROM MANZANILLO TO CABO CORRIENTES HAS BEEN
DISCONTINUED.

FORECAST POSITIONS AND MAX WINDS

INIT 07/1500Z 20.0N 107.3W 60 KT 70 MPH
12H 08/0000Z 20.8N 108.5W 55 KT 65 MPH
24H 08/1200Z 21.9N 110.0W 50 KT 60 MPH
36H 09/0000Z 23.0N 111.8W 45 KT 50 MPH
48H 09/1200Z 24.0N 113.8W 35 KT 40 MPH...POST-TROPICAL
72H 10/1200Z 25.5N 117.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 11/1200Z 25.5N 119.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 12/1200Z...DISSIPATED

$$
FORECASTER BLAKE/STEWART

Member Since: April 29, 2009 Posts: 75 Comments: 14315
Quoting 2073. wunderkidcayman:

Yep almost closed circulation just open on the SW side


True and yeah I got the alert on my IPad says cyclist is dead in this accident



Sad! Ithink we'll have a TD by early evening or tonight.
Member Since: April 29, 2007 Posts: 0 Comments: 7930
95L is small, dry and moving too quickly. I don't expect much from it.
Member Since: July 20, 2008 Posts: 0 Comments: 2927
Quoting 2068. stormpetrol:
Link

Look at at this loop you can LLC at around 9.8N/42.1W

Yep see it

Member Since: June 13, 2009 Posts: 2 Comments: 12147
95L needs to build convection on the eastern side
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Quoting 2054. AussieStorm:
Is this real???





@miasosiak Mia Sosiak 16m
Saturday's hailstorm in Airdrie area, courtesy of Cpt. Daryl Frank, Jazz Aviation. Cool view!
Looks to be. There are a number of videos on YouTube showing the event.

Nice image.
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Quoting 2067. MiamiHurricanes09:
There isn't any "circulation" really...just an elongated trough.


There's a circulation, however it appears to be only half-closed. It's better than it was yesterday, however it still has a lot of work to do. Not bad though for something hauling at 24mph.
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Quoting 2069. FOREX:


This reminds me of a storm a few years ago that was speeding across the Atlantic, but in the end when it made landfall it stalled and sat and sat for days ruining a lot of peoples lives. Anything can happen with this.
Reminds me and perhaps very similar conditions to TS Emily..."The cyclogenesis of Tropical Storm Emily was complicated, extending over several days from late July into early August. An easterly tropical wave%u2014an equatorward trough of low pressure%u2014exited the west African coast in the fourth week of July, at which point it became largely embedded within the monsoon trough.[1] Located to the south of a ridge of high pressure, the wave moved west-northwestward across the open Atlantic."
Member Since: June 30, 2013 Posts: 12 Comments: 8428
Quoting 2061. nrtiwlnvragn:
Manati ASCAT B solution a little better...... still not closed.



Yep almost closed circulation just open on the SW side

Quoting 2062. stormpetrol:


Speed of 95L reminds of Dean 07, BTW I see on my BB Serious car accident in WB, Hell Road closed!

True and yeah I got the alert on my IPad says cyclist is dead in this accident

Member Since: June 13, 2009 Posts: 2 Comments: 12147
Quoting 2067. MiamiHurricanes09:
There isn't any "circulation" really...just an elongated trough.



But really good outflow it looks like
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Early and mid-July tropical disturbances in the Atlantic usually move forward quite quickly as compared to later in the season. 95L is holding together quite well at the present time despite its fast forward speed. It will have to gain at least a couple of degrees latitude to avoid running into South America in two or three days.
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95L is a typical WU invest, a slow organizing system with potentional. Keep watching the TWO for further updates.
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2069. FOREX
Quoting 2060. GTstormChaserCaleb:
Once 95L slows down even a little bit it should begin to organize and may even take off like the HWRF and GFDL are suggesting. A wait and see right now.


This reminds me of a storm a few years ago that was speeding across the Atlantic, but in the end when it made landfall it stalled and sat and sat for days ruining a lot of peoples lives. Anything can happen with this.
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Link

Look at at this loop you can LLC at around 9.8N/42.1W
Member Since: April 29, 2007 Posts: 0 Comments: 7930
Quoting 2053. wunderkidcayman:

Nope there is a good circulation however it's not closed yet
There isn't any "circulation" really...just an elongated trough.
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From Mark Sudduth:

At the very least it will bring showers and gusty winds to the area as it passes by. Whether or not it will be more than that remains to be seen. Climatology argues against it but this season may be different than the average season and as such, we should watch this feature closely.
Member Since: August 14, 2010 Posts: 10 Comments: 17075
Quoting 2061. nrtiwlnvragn:
Manati ASCAT B solution a little better...... still not closed.


Nope, but seeing Tropical Storm force winds, once a center closes off we should see a re-number.
Member Since: June 30, 2013 Posts: 12 Comments: 8428
Quoting 2056. washingtonian115:
All we need now is a closed low and we will have T.D 3.
This reminds me of storms like Dolly and Irene who had T.S force winds but not the closed low level circulation.95L is getting there and don't be surprised to see a re-number sometime today.Also I believe a upper level anti-cyclone is trying to form over head of our system.

Agreed

Member Since: June 13, 2009 Posts: 2 Comments: 12147
A lot of the GFS ensembles want to take it to either Florida or the Carolina's
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Quoting 2053. wunderkidcayman:

Nope there is a good circulation however it's not closed yet


Speed of 95L reminds of Dean 07, BTW I see on my BB Serious car accident in WB, Hell Road closed!
Member Since: April 29, 2007 Posts: 0 Comments: 7930
Manati ASCAT B solution a little better...... still not closed.


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Once 95L slows down even a little bit it should begin to organize and may even take off like the HWRF and GFDL are suggesting. A wait and see right now.
Member Since: June 30, 2013 Posts: 12 Comments: 8428
95L looking better this morning, starting to see more turning in the cloud field. That being said, this system still has some work to do.

I dont expect development until tomorrow night or Tuesday at the earliest, if that
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Quoting 2043. Grothar:
Still keeping an eye on this. I don't expect much, but it could bring some good storms to the Florida east coast.



Local mets saying Tuesday should be a wet one.
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Good morning all....looks like 95L has good outflow this morning
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All we need now is a closed low and we will have T.D 3.
This reminds me of storms like Dolly and Irene who had T.S force winds but not the closed low level circulation.95L is getting there and don't be surprised to see a re-number sometime today.Also I believe a upper level anti-cyclone is trying to form over head of our system.
Member Since: August 14, 2010 Posts: 10 Comments: 17075
Quoting 2049. MiamiHurricanes09:
95L still a mess at the surface.


Is moving too fast, the trade winds are kicking him!
Member Since: June 20, 2012 Posts: 0 Comments: 2159
Is this real???





@miasosiak Mia Sosiak 16m
Saturday's hailstorm in Airdrie area, courtesy of Cpt. Daryl Frank, Jazz Aviation. Cool view!
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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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