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 1348. sar2401:

OK, I'll betcha a buck that it won't become a TD or TS by this time tomorrow.

Trust me you don't want to do this
Member Since: June 13, 2009 Posts: 2 Comments: 11136
Quoting 1346. redwagon:
I just can't imagine what 6am will bring with 94L. RGB couldn't see the surface what with the hot mess, there could be a circulation at the sfc and we'd never know it.

Erick is feeding it energy and moisture hand over fist, and it did advance against the ridging out of TX. It's still active. Does anybody have idea other than RIP?


Surface trough has already lifted off to the north. So.

.

Edit: Hmm, that did not work - should have previewed it, don't you think?
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Dalila was one fighter though, for a flyweight, she held on and on and on.
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TROPICAL DEPRESSION DALILA DISCUSSION NUMBER 30
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042013
800 PM PDT SAT JUL 06 2013

A LITTLE BIT OF DEEP CONVECTION WAS OCCURRING TO THE WEST OF THE
LOW-LEVEL CENTER OF DALILA EARLIER...BUT THE LAST SIGNIFICANT BURST
DISSIPATED A FEW HOURS AGO. STRONG UPPER-LEVEL EASTERLY WINDS AND
SUBSIDENCE ASSOCIATED WITH THE OUTFLOW OF HURRICANE ERICK IS
SQUELCHING THE RE-DEVELOPMENT OF CONVECTION...AND SHOULD CONTINUE TO
DO SO ACCORDING TO THE MODEL GUIDANCE. IF THE SYSTEM REMAINS
ABSENT OF DEEP CONVECTION FOR MUCH LONGER...IT WILL LIKELY BE
DESIGNATED A REMNANT LOW. THE INTENSITY IS HELD AT 25 KT FOR THIS
ADVISORY...BUT THE WINDS SHOULD WEAKEN FURTHER IF NO NEW CONVECTION
REFORMS SOON. THE INTENSITY FORECAST IS THE SAME AS BEFORE...AND
IN LINE WITH THE BULK OF THE MODEL INTENSITY OUTPUT.

DALILA DRIFTED SOUTH-SOUTHWESTWARD DURING THE PAST SEVERAL HOURS...
BUT APPEARS TO HAVE SHIFTED ITS HEADING TOWARD THE EAST OR EAST-
SOUTHEAST MORE RECENTLY. GLOBAL MODELS SHOW THE CYCLONE OR ITS
REMNANTS GRADUALLY BEING ABSORBED BY THE LARGER CIRCULATION OF
HURRICANE ERICK DURING THE NEXT COUPLE OF DAYS...FIRST MOVING
EASTWARD AND THEN TURNING NORTHWARD. THE OFFICIAL FORECAST IS
NUDGED SLIGHTLY TO THE RIGHT OF THE PREVIOUS ONE BUT IS GENERALLY
LEFT OR NEAR THE MULTI-MODEL CONSENSUS.


FORECAST POSITIONS AND MAX WINDS

INIT 07/0300Z 16.8N 113.0W 25 KT 30 MPH
12H 07/1200Z 16.8N 112.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 08/0000Z 16.9N 112.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
36H 08/1200Z 17.4N 112.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
48H 09/0000Z 18.0N 112.4W 15 KT 15 MPH...POST-TROP/REMNT LOW
72H 10/0000Z...POST-TROP/REMNT LOW

$$
FORECASTER KIMBERLAIN
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Once 95L reaches 40-50W it should slow down a bit to around 15 mph
Member Since: June 13, 2009 Posts: 2 Comments: 11136
BULLETIN
TROPICAL DEPRESSION DALILA ADVISORY NUMBER 30
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042013
800 PM PDT SAT JUL 06 2013

...DALILA ALMOST A REMNANT LOW...


SUMMARY OF 800 PM PDT...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...16.8N 113.0W
ABOUT 465 MI...750 KM SSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...30 MPH...45 KM/H
PRESENT MOVEMENT...E OR 90 DEGREES AT 1 MPH...2 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES

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1348. sar2401
Quoting stormpetrol:
95L is going be something, like it or not, this tropical low imo is very near TD status. I can clearly see this becoming a TD/TS sometime tomorrow.

OK, I'll betcha a buck that it won't become a TD or TS by this time tomorrow.
Member Since: October 2, 2004 Posts: 0 Comments: 13266
1347. beell

Unenhanced IR
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I just can't imagine what 6am will bring with 94L. RGB couldn't see the surface what with the hot mess, there could be a circulation at the sfc and we'd never know it.

Erick is feeding it energy and moisture hand over fist, and it did advance against the ridging out of TX. It's still active. Does anybody have idea other than RIP?
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1345. sar2401
Quoting Hurricanes305:

Here is some of the GFS ensemble:



Which again I just speculating as I normally dont go that far out but the pattern is straight forward keep it on a general west to WNW movement before a trough comes and digs it out and put it in the Eastern Gulf/Florida/Bahamas region similar to the HWRF. But its not set in stone and is subject to plenty of changes. 

Here is http://www.tropicaltidbits.com/ to Levi video explaining it and a path into that general region. 

The GFS ensemble does the best it can out to about 13N, 57W. After that, it starts to spread out to everywhere from Jamaica to North Carolina. 95L has to get about 15N before it starts to present a threat to anything other than the far south Caribbean. Once it gets past 15N and you start to see a few other model ensembles tighten up, you might have something. As of now, you can predict anything from early death to Cape Hatteras with about a 50/50 chance of being right. Everyone was all excited about 94L a few days ago as well, but invests without a closed low are subject to so many vagaries that it comes down to mere guessing at this point.
Member Since: October 2, 2004 Posts: 0 Comments: 13266
nice round now!!
37 west
Member Since: March 12, 2013 Posts: 8 Comments: 13623
Still 30% at 2pm unless it develops more convection. Cait wait till tomorrow have a good nite. Btw what start to a long  two month CV season. Giving goosebumps to find out what could be getting ready to take the Atlantic.
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Quoting 1340. stormpetrol:
95L is going be something, like it or not, this tropical low imo is very near TD status. I can clearly see this becoming a TD/TS sometime tomorrow.

Yes very true

Also looking at 95L zoomed out it is moving out of dead due W and soon will be near or above 10N

Member Since: June 13, 2009 Posts: 2 Comments: 11136


Very very close to closing off.
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95L is going be something, like it or not, this tropical low imo is very near TD status. I can clearly see this becoming a TD/TS sometime tomorrow.
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Quoting 1328. interstatelover7166:
What percentage chance of 95L ever becoming a storm?
A. 10%
B. 30%
C. 50%
D. 70%
E. 90%
F. 100%
G. Never/inbetween/etc.


H. Too early to tell.
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Quoting 1328. interstatelover7166:
What percentage chance of 95L ever becoming a storm?
A. 10%
B. 30%
C. 50%
D. 70%
E. 90%
F. 100%
G. Never/inbetween/etc.
gave it 30% right now
Member Since: March 12, 2013 Posts: 8 Comments: 13623
sar2401, you're a wishcaster's worst nightmare. 95L could fade and die or be dangerous, just too early to tell; certainly a prelude to what the season holds in store though. Wave coming off Africa looks good and future waves look like they'll be coming off with vigor. Model track for 95L isn't good if it does hold and grow. Glad your a downcaster though Sar, balances out we wishcasters. You owe me a dollar by the way, just wait. ;)
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Quoting 1329. Camille33:
Td is likely to form during the night, heavy tstm's are persisting.
Holding steady needs some help from DMAX to gain some bulk and some fresh ASCAT/OCEAN pass which a closed low before the NHC upgrade. Looking good
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Quoting 1328. interstatelover7166:
What percentage chance of 95L ever becoming a storm?
A. 10%
B. 30%
C. 50%
D. 70%
E. 90%
F. 100%
G. Never/inbetween/etc.


C. 50%
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I see the center with no rain with it.. I am keep it at 30% at 2am
Member Since: March 12, 2013 Posts: 8 Comments: 13623
Quoting 1329. Camille33:
Td is likely to form during the night, heavy tstm's are persisting.

maybe but maybe thats too early
Member Since: June 13, 2009 Posts: 2 Comments: 11136
1332. sar2401
Quoting wunderkidcayman:
also this growing convection is clearly seen on the JSL loop

95L is like a lonely asteroid wandering in the outer space of 8.2N. It has some convection, but lots of lonely wanderers in the ITCZ have convection. It has no discernable center and it's tiny. It's clipping alomg at 20 knots west. If it does not start to gain latitude in the next 36 hours, the coast of South America is coming up fast. I just can't get excited about a wave that has so little going for it right now. 48 hours from now, it will either be something that has potential or it will die a lonely death somewhere off the coast of Venezuela.
Member Since: October 2, 2004 Posts: 0 Comments: 13266

Quoting 1322. sar2401:

Well, 95 has a circulation but it does not have a well defined center and it's not a closed low. There are lots of waves that will form this season with well-defined circulations that do nothing. We already had one with 92L. The GFS doesn't even want to take 95 to Barbados before dropping it, the only one that want to take ot the Bahamas is HWRF, and the HWRF is not known as a reliable tropical model. I fail to see where a trough is coming along in the Caribbean to dig out anything. I realize it's fun to look at models, but this is a wave that's still hung up in the ITCZ. It's way too early to know if it will survive, let alone threaten Florida or the Bahamas.
Here is some of the GFS ensemble:



Which again I just speculating as I normally dont go that far out but the pattern is straight forward keep it on a general west to WNW movement before a trough comes and digs it out and put it in the Eastern Gulf/Florida/Bahamas region similar to the HWRF. But its not set in stone and is subject to plenty of changes. 

Here is http://www.tropicaltidbits.com/ to Levi video explaining it and a path into that general region. 
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Quoting 1328. interstatelover7166:
What percentage chance of 95L ever becoming a storm?
A. 10%
B. 30%
C. 50%
D. 70%
E. 90%
F. 100%
G. Never/inbetween/etc.

D
E
F
Member Since: June 13, 2009 Posts: 2 Comments: 11136
Td is likely to form during the night, heavy tstm's are persisting.
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What percentage chance of 95L ever becoming a storm?
A. 10%
B. 30%
C. 50%
D. 70%
E. 90%
F. 100%
G. Never/inbetween/etc.
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Quoting 1317. SLU:

hmm its pretty much there just needs to sharpin up some should do that by sunrise
Member Since: June 13, 2009 Posts: 2 Comments: 11136
Quoting 1246. Hurricanes305:


Basically what I was saying is it is getting more active on the blog as we reach the Peak and CV waves are getting going much earlier.
Yes, seems very early for the CV Season. I usually ignore these until mid August, but this wave could hold together.
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1325. SLU
Evidence of a nearly closed circulation despite the rapid movement.

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Quoting 1312. hurricanes2018:
INVEST 95L need more heavy rain in the center..its not looking so good right now.
Calm down it doing absolutely great for a system in DMIN. In fact although convection has wane it has been persistent since it fired up this afternoon. Surface convergence is now focusing right over the LLC and the vorticity is slowly consolidating. With a decent DMAX which is coming up it just may close off tomorrow evening.  
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Quoting 1310. moonlightcowboy:


Have a good sleep, Taz. You made some good posts today. Thanks. :)



thanks
Member Since: May 21, 2006 Posts: 5091 Comments: 114756
1322. sar2401
Quoting Hurricanes305:


It does have a well define circulation but its not closed but it definately on its way. In anycase the models are in pretty decent agreement for being this early on so We will have to watch it carefully.

8pm Models:




Looks to me that the HWRF may have a general track that fits the potential setup as a trough will dig it out the Caribbean and put it in the Bahamas area. GFS looks to agree in the short term with it. Still too early though.

Well, 95 has a circulation but it does not have a well defined center and it's not a closed low. There are lots of waves that will form this season with well-defined circulations that do nothing. We already had one with 92L. The GFS doesn't even want to take 95 to Barbados before dropping it, the only one that want to take ot the Bahamas is HWRF, and the HWRF is not known as a reliable tropical model. I fail to see where a trough is coming along in the Caribbean to dig out anything. I realize it's fun to look at models, but this is a wave that's still hung up in the ITCZ. It's way too early to know if it will survive, let alone threaten Florida or the Bahamas.
Member Since: October 2, 2004 Posts: 0 Comments: 13266
Quoting Patrap:


Gui-Ying Yang and Julia Slingo

...
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Quoting 1316. Hurricanes305:

Sleep well you might wake up something interesting. It was a great day for wave watching :)



yep cant wait for AM
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also this growing convection is clearly seen on the JSL loop
Member Since: June 13, 2009 Posts: 2 Comments: 11136
Good evening everyone

Needless to say, all eyes over here are watching 95L very closely.

Tomorrow we make arrangements to have our Chris Craft pulled out of the water in the next couple of days for the season. The smaller boat stays in the water as that is the one we use for fishing. If anything were to come along, that one would just get pulled out and tied up.

Thanks to many of you, all the lurking and reading has finally started to pay off, and I'm actually starting to understand a lot of the information you post!

Lindy
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1317. SLU
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Quoting 1308. Tazmanian:




ok i think



well good night 95L and evere one see you in the AM
Sleep well you might wake up something interesting. It was a great day for wave watching :)
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examining the ir 95L floater loop 95L is starting to build convection on its E side and also I think that 95L has a closed LLCOC now or at least very very close to having one
Member Since: June 13, 2009 Posts: 2 Comments: 11136
1314. SLU
The ASCAT shows that the low may be further west

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Quoting 1310. moonlightcowboy:


Have a good sleep, Taz. You made some good posts today. Thanks. :)




welcome
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INVEST 95L need more heavy rain in the center..its not looking so good right now.
Member Since: March 12, 2013 Posts: 8 Comments: 13623

Quoting 1301. moonlightcowboy:
Vorticity is not quote as elongated as earlier. Convergence is tighter now, and is obviously getting some surface lift shown by a comparative amount of divergence aloft. I think this confirms, despite its fast forward speed still, that its trying to cut its moisture umbilical to the Itcz. This may also mean that its gaining some strength and may well have or trying to close a surface circulation. As long as it can keep converging winds streaming in from all sides, create surface lift and divergence aloft, it can get the tropical engine going and build its moisture field protecting it from the dry air. Still needs to slow down though.



Convergence




Divergence
Wow it has tighten up well in the last 6 hours I'm kinda impressive even though it moves quite fast but it will slow down if this keeps up later tonight and into Sunday. Man one can only image what powerful cane is getting ready to be unleashed in the Atlantic once August & September comes; one can only imagine.
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Quoting 1308. Tazmanian:




ok i think



well good night 95L and evere one see you in the AM


Have a good sleep, Taz. You made some good posts today. Thanks. :)
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Quoting 1307. interstatelover7166:
Certainly moist enough for when, but if, 95L makes it to the GOM.



right now none of the modes are talking it to the gulf it looks like NC is now in play
Member Since: May 21, 2006 Posts: 5091 Comments: 114756
Quoting 1305. Hurricanes305:
Man talk about errors in that post glad you understand. But that could be just what the doctor ordered for 95L.




ok i think



well good night 95L and evere one see you in the AM
Member Since: May 21, 2006 Posts: 5091 Comments: 114756
Quoting 1282. Patrap:


Certainly moist enough for when, but if, 95L makes it to the GOM.
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If 95L looks impressive tomorrow morning, the chances will probably go up very gradually.
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Quoting 1295. Tazmanian:



yep
Man talk about errors in that post glad you understand. But that could be just what the doctor ordered for 95L.
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this little guy may be in the next two at 2am or 8am


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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.