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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Quoting 190. BahaHurican:
Well, well, well.... say Tropical rains in TX and out pops Rand... howareya, man?




Hey Baha! Long time... been just lurking a lot as of late.
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I expect heavy rain in South Florida fro our cold core coming in from the east. If this were August this would be no joke. Path and quickness reminds me of Andrew.
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Quoting 248. RTSplayer:
It'll probably be another 24 hours before NHC increases the percent on 95L.

Reasoning for this is based on the current GFS vorticity forecast, because if you go out 48 to 72 hours, it starts to show some vorticity. That would give a 48 forecast (24 hours from now) a good range of vorticity improvement.

So I figure the next percent increase on 95L will be at the 12UTC tomorrow.




that is vary unlikey the nhc will likey be bumping it up too 30 too %50 at the next two
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Quoting 242. SLU:


Only the SAL would prevent development through 72 hrs but it may run into the STJ after 60W if it moves too far north.
But if it stays further south then we may have something to talk about.Looks like it's not pulling north any time soon.
Quoting 235. stormchaser19:
Still 360 hours out.But I hope Boltocane sees this.
Member Since: August 14, 2010 Posts: 10 Comments: 16971
250. SLU
Quoting 235. stormchaser19:


This is going to be a big, big season...
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Quoting 246. stormpetrol:
95L looks like it could take a Dean 07 track to me.




not this year




mx is safe from storms this year
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It'll probably be another 24 hours before NHC increases the percent on 95L.

Reasoning for this is based on the current GFS vorticity forecast, because if you go out 48 to 72 hours, it starts to show some vorticity. That would give a 48 forecast (24 hours from now) a good range of vorticity improvement.

So I figure the next percent increase on 95L will be at the 12UTC tomorrow.
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Quoting 238. RTSplayer:


lol.

I forecast the next frame's forecast. It crosses Cuba in the exact spot as Gustav. I didn't cheat.

Ok, this is going to move around a lot though, so I'm obviously not calling that just yet. I suck at open waves.
A lot can happen. What is interesting, if it strengthens in the Caribbean, the track will be north, if it stays weak, it could end up in the Western Caribbean and intensify there.
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95L looks like it could take a Dean 07 track to me.
Member Since: April 29, 2007 Posts: 0 Comments: 7862
Quoting 241. yonzabam:
95L looks pretty decent to me, so I'm surprised by the conservative predictions for it. Shear is low until it reaches the Carib, so what's preventing it becoming a hurricane down the line? Is it just climatology?




wind shear may be gone by time it hits the Carib has wind shear has been droping






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Back on my computer now. Long range GFS shows a strong wave in the Lesser Antilles on the 22nd.

Member Since: April 29, 2009 Posts: 75 Comments: 14249
242. SLU
Quoting 177. washingtonian115:
This really does remind me of Ernesto.Even if it doesn't develop before it get's to the islands it may need to be watched in the caribbean if shear isn't screaming it's head off.


Only the SAL would prevent development through 72 hrs but it may run into the STJ after 60W if it moves too far north.
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95L looks pretty decent to me, so I'm surprised by the conservative predictions for it. Shear is low until it reaches the Carib, so what's preventing it becoming a hurricane down the line? Is it just climatology?
Member Since: July 20, 2008 Posts: 0 Comments: 2925
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Quoting 232. GTstormChaserCaleb:
With the way the Bermuda High is sitting over Bermuda that seems the most plausible solution.
Yes the Bermuda high should be retreating from my area after about Tuesday so that 95L may turn more north and avoid moving into central america.Ya see how Washington still effects people in many ways?.lololol.
Member Since: August 14, 2010 Posts: 10 Comments: 16971
Quoting 229. hydrus:
7 day into gulf.


lol.

I forecast the next frame's forecast. It crosses Cuba in the exact spot as Gustav. I didn't cheat.

Ok, this is going to move around a lot though, so I'm obviously not calling that just yet. I suck at open waves.
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Maybe we should Change 94-L to 94-P (for persistence).
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Quoting 224. Tazmanian:
poll time


what will 95L be at the 2pm two


A %30

B %40

C %50

D %60 or higher

Quoting 226. wunderkidcayman:
I say 95L will stay south of PR Haiti and Cuba and Jamaica is my bet



B. 40%

It will have to be pretty weak to stay that far south. And the trade winds will also give it a hard time. Thus it wont amount to much.
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Member Since: June 20, 2012 Posts: 0 Comments: 2159
eeeeeeeeeeeeek! if wind shear get low by time 95L gets in there watch out

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Quoting 224. Tazmanian:
poll time


what will 95L be at the 2pm two


A %30

B %40

C %50

D %60 or higher


none of the above. Still 20%
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Quoting 222. hydrus:
weather maps keep 95L south, and into the Caribbean.
With the way the Bermuda High is sitting over Bermuda that seems the most plausible solution.
Member Since: June 30, 2013 Posts: 12 Comments: 8212
Weird stuff can happen in the GOMEX, like this little
event in 1997..

Link
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Quoting 224. Tazmanian:
poll time


what will 95L be at the 2pm two


A %30

B %40

C %50

D %60 or higher

Looking at it it's good looking so I give it 30% infact

94L 30-50%
95L 30-40%
Member Since: June 13, 2009 Posts: 2 Comments: 11975
7 day into gulf.
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Quoting 222. hydrus:


Yeah, that doesn't show the northern scenario at all.

Ok, yeah, that looks like the first half of Gustav's track. Lots of close encounters and interaction with the islands potentially, but the center may stay over water the whole way.
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Quoting 218. RTSplayer:


Yeah, I saw the more up to date model as well, I mentioned it at the end of the other blog/thread before I realized it was dead.

I still like to see 2 or 3 runs in a row give similar results, but the newer run agrees with my intuition.

===

For 94L, I notice it is consolidating into one storm complex now, so it's possible it could begin to develop it's own outflow soon enough. Water is still 29 t0 30C SST, so even though it's not very deep heat it is enough for significant development if the storm stays away from land, and if the shear doesn't pick back up.
Can you post the link?
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I say 95L will stay south of PR Haiti and Cuba and Jamaica is my bet
Member Since: June 13, 2009 Posts: 2 Comments: 11975
Quoting 220. GTstormChaserCaleb:
6 days for 95L to approach south of Cuba, that is fast!

Models are downplaying this just like they did for Ernesto.They showed Ernesto as a open wave in the WCARB only for it in the end to be a 100mph storm.
Member Since: August 14, 2010 Posts: 10 Comments: 16971
poll time


what will 95L be at the 2pm two


A %30

B %40

C %50

D %60 or higher
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Its been fun. I will go. See you soon.
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weather maps keep 95L south, and into the Caribbean.
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Hey guy I knew we would have 95L now we got stuff to track
Member Since: June 13, 2009 Posts: 2 Comments: 11975
6 days for 95L to approach south of Cuba, that is fast!

Member Since: June 30, 2013 Posts: 12 Comments: 8212
G'morning/afternoon all,

Hope everyone had a fantastic 4th!

Here in OK, our wonderful vacation from typical summer weather has ended. Winds have shifted back outta the south, temps a have crept back up into the mid-90's and are expected to take that dreaded leap into the 100's this upcoming week.

It looks 94L will do nothing more than give peeps, who need it, a good soaking. 95L might do something if it ducks under the shear, but I have my doubts.

Hopefully, 94L and Hurricane Erik will toss enough moisture up into Texas and the SW to help mitigate the ongoing drought.

Have a fantastic day! Will stop by when I can.

Cheers
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Quoting 202. BahaHurican:
Just saw a more recent model run that puts 95L south of PR, which makes a lot more sense.

Looks like CaribBoy may get his rain after all... :o)


Yeah, I saw the more up to date model as well, I mentioned it at the end of the other blog/thread before I realized it was dead.

I still like to see 2 or 3 runs in a row give similar results, but the newer run agrees with my intuition.

===

For 94L, I notice it is consolidating into one storm complex now, so it's possible it could begin to develop it's own outflow soon enough. Water is still 29 t0 30C SST, so even though it's not very deep heat it is enough for significant development if the storm stays away from land, and if the shear doesn't pick back up.
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Quoting 211. xcool:
maybe flight get scheduled soon for 94L
SoonER? yes. Soon? notsomuch

I gone.
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my beats are on 95L



94L is nothing but a big mess
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Quoting 211. xcool:
maybe flight get scheduled soon for 94L


There are no flights for today or tomorrow unless they add at the last minute.

REPRPD
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1100 AM EDT SAT 06 JULY 2013
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 07/1100Z TO 08/1100Z JULY 2013
TCPOD NUMBER.....13-036

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
Member Since: April 29, 2009 Posts: 75 Comments: 14249

Quoting 202. BahaHurican:
Just saw a more recent model run that puts 95L south of PR, which makes a lot more sense.

Looks like CaribBoy may get his rain after all... :o)
Can you show me the link.
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Quoting 211. xcool:
maybe flight get scheduled soon for 94L

How do you know?
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Right... I need to get out of here for a while. I gotta admit I didn't expect 95L to be this interesting. Frankly, I don't care if it never actually develops. Just having something to watch is GREAT!

Pity we can't count on it somehow blowing up to cat 5 [excitement!] and exiting stage right before hitting anything [Whew!]....
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211. xcool
maybe flight get scheduled soon for 94L
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Quoting 195. Hurricanes305:

That is exactly what I was talking about the ULL was enhancing the upper level wind over the Eastern Caribbean however its been decreasing as  the ULL moves west. 



yep



and and high wind shear may no longer be a playing by time 95L gets there but by then this may be a strong TS


evere one needs too watch 95L vary closeey
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Quoting 196. RTSplayer:


I don't think it goes that far north, which is a good thing for development, but a bad thing for someone further down the line.

The model may be over playing the weakness there, so give it another 12 to 24, and if it's still doing the same thing, we can convince ourselves it's legit.


The entire BAM group of models takes it pretty far north, but I only trust those for a day or two. They aren't that great at the end of the run.

Point is all the models are taking it farther north than I would say it would go as a human.
the 12z GFS takes it over Martinique/Dominca the middle of the Lesser Antilles as a tropical wave if it can get going a before reaching the Lesser Antilles a track South or Over PR is not impossible. 
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big bad Hurricane Hugo :) I was 8 and living in San Juan, PR at the time and remember it like it was yesterday.
Quoting 197. 62901IL:

the "H" storm? I am afraid i don't remember that one...
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Quoting 197. 62901IL:

the "H" storm? I am afraid i don't remember that one...
You need a tongue-in-cheek pic for this one... lol

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Quoting 202. BahaHurican:
Just saw a more recent model run that puts 95L south of PR, which makes a lot more sense.

Looks like CaribBoy may get his rain after all... :o)


Hmm not so sure :(((( but we will see :))))))
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Don't like the image post #147 is showing. Praying for a quiet year here on the coast.
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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.