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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HERE WE GO!! maybe adding invest 96L SOON
Member Since: Posts: Comments:
1903. ncstorm
I just saw the 00z CMC run..

I dont know why it mostly aims for the carolinas..it just needs to pack its bags and rent a time share here since it constantly tries to make a trip here
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TAFB still at dvorak 1.5

AL 95 201307071145 DVTS 930N 4110W TAFB JA 1515 ///// Applied banding feature to the NW for Data T-no.
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Quoting 1895. ryang:
Interesting to see the T numbers increased to 2.0. I wonder if the NHC can reschedule RECON to tomorrow afternoon?

We will have to wait till new recon schedule come out later today
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1900. JonasNJ
Wow is that the dry line on the Infra-red Satellite image?
sat image
current weather
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Looks like Texas will get something out of the Gulf disturbance after all.

off to my Sunday mixed doubles
l8r
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1898. pcola57
Quoting 1892. pcola57:
Ok...
Once again I've got "Average" showing and I made no selection..
Anybody else getting that and know what to do about it??
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DISTURBANCE INVEST (AL952013) 20130707 1200 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
130707 1200 130708 0000 130708 1200 130709 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 9.0N 40.8W 10.4N 45.5W 12.1N 50.7W 14.2N 55.7W
BAMD 9.0N 40.8W 9.9N 45.1W 11.2N 49.4W 12.9N 53.4W
BAMM 9.0N 40.8W 10.0N 45.5W 11.3N 50.4W 13.0N 55.0W
LBAR 9.0N 40.8W 10.0N 45.0W 11.4N 49.6W 13.0N 54.0W

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
130709 1200 130710 1200 130711 1200 130712 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 16.3N 60.9W 20.3N 70.1W 24.0N 75.9W 27.8N 77.6W
BAMD 14.6N 56.9W 17.2N 62.5W 18.2N 65.7W 17.6N 67.4W
BAMM 14.8N 59.4W 18.3N 67.3W 21.8N 72.7W 24.9N 74.7W
LBAR 14.5N 58.2W 18.1N 64.7W 28.2N 55.3W 26.4N 56.3W

...INITIAL CONDITIONS...
LATCUR = 9.0N LONCUR = 40.8W DIRCUR = 280DEG SPDCUR = 21KT
LATM12 = 8.4N LONM12 = 36.6W DIRM12 = 279DEG SPDM12 = 21KT
LATM24 = 7.9N LONM24 = 32.7W
WNDCUR = 30KT RMAXWD = 50NM WNDM12 = 25KT
CENPRS = 1008MB OUTPRS = 1012MB OUTRAD = 150NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM
Member Since: April 29, 2009 Posts: 75 Comments: 14908
I think 95L should start to slow down once it reaches 43W/45W
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1895. ryang
Interesting to see the T numbers increased to 2.0. I wonder if the NHC can reschedule RECON to tomorrow afternoon?
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Quoting 1874. CybrTeddy:
Good morning all! I can see many of you have jumped onto your usual habit of judging a storms fate by each change in the satellite frame.

Indeed. I was giving myself a few facepalms at earlier comments this morning. -_-
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Quoting 1875. Chicklit:
...now that's better paps! I'll have the egg whites with the whole wheat and some fruit with a cup of 50/50 caf/decaf!


Since Grothar's heart attack I've been doing breakfasts half and half, half heart healthy and half sweet and not really healthy. We all need our strength to keep up with the blog and weather. *G*
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1892. pcola57
Ok...
Once again I've got "Average" showing and I made no selection..
Anybody else getting that and know what to do about it??
Member Since: Posts: Comments:
Quoting 1886. SLU:
AL, 95, 2013070712, , BEST, 0, 90N, 408W, 30, 1008, WV, 34, NEQ, 0, 0, 0, 0, 1012, 150, 50, 0, 0, L, 0,


Hmm pressure drop 1mb
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Really zipping along...

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Quoting 1880. Chicklit:

c'mon Cybrted, you're a bit cynical this morning...just watching to see what the sunlight brings. 95L is looking pretty decent in post #1858.


I guess I am! Haven't had my coffee yet. ;)
Member Since: July 8, 2005 Posts: 259 Comments: 24578
Quoting 1885. GatorWX:


I think a closed surface circulation appears evident on vis. Look at the loop and it appears moving wnw away from the itcz at 9.5, 41. Banding is becoming better defined, but so is drier air, so we'll see.

I don't think dry air should be too much of a problem
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invest 95L got a new friend!! its back of invest 95L
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1886. SLU
AL, 95, 2013070712, , BEST, 0, 90N, 408W, 30, 1008, WV, 34, NEQ, 0, 0, 0, 0, 1012, 150, 50, 0, 0, L, 0,
Member Since: July 13, 2006 Posts: 13 Comments: 5367
1885. GatorWX


I think a closed surface circulation appears evident on vis. Look at the loop and it appears moving wnw away from the itcz at 9.5, 41. Banding is becoming better defined, but so is drier air, so we'll see.
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95L looks fair this morning. It's in and going toward dry air, moving way too fast and doesn't have a closed LLC. It probably will become a TD, but no more than a TS if it doesn't slow down or hit Hispaniola. Moving at 25 mph is too fast for major development and the mountains of DR weaken most anything that brushes there. I wouldn't be suprised if it makes it to the East Coast, but it won't be strong UNLESS those things mentioned happen.

In other news, I see 94L is gone, and there's some good waves behind 95. The CV season has begun and it's spinnin off some good ones for bein the first week of July.
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1883. pcola57
Lemon/Cranberry muffins for me with strong coffee and a glass of milk..
Thanks apps..
I'm full now.. :)
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I SEE two very gooD tropical wave invest 95L and maybe invest 96L down the road!
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Quoting aislinnpaps:
Good morning, everyone. Afternoon, Barbamz and VR. Evening, Aussie. Starting the day off at a warm 74 that feels like 78 degrees. There's a 50% chance of rain, but none in sight. I live in hope. *G*

Breakfast's on the sideboard: egg whites and salmon on toasted whole wheat English muffin with a tomato, whole grain waffles with cherry sauce, apple-bacon pancakes with cider syrup, lemon cranberry muffins, turkey bacon, extra lean ham, fresh fruit and choice of orange or apple juice. Everything is heart healthy, all in honor of Grothar. Enjoy!


Evening. You've made me hungry. I'll go make English Muffins with Butter and Honey. Oh and it's 10:30pm here.
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Quoting 1874. CybrTeddy:
Good morning all! I can see many of you have jumped onto your usual judging a storms fate by each satellite frame.

c'mon Cybrted, you're a bit cynical this morning...just watching to see what the sunlight brings. 95L is looking pretty decent in post #1858.
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Quoting 1866. Grothar:



That's old.


So are you.
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Quoting 1873. AussieStorm:
Anyone here agree on this...



and...


Nope not one bit of it

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1877. pcola57
Storm totals for us down here..

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95L is doing great dispite the conditions surrounding it dry air and SAL it moving fastthe downward pulse of the MJO Dispite that its still here not dry and Not a naked swirl plus with condition expected to get better it will do better
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...now that's better paps! I'll have the egg whites with the whole wheat and some fruit with a cup of 50/50 caf/decaf!
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Good morning all! I can see many of you have jumped onto your usual habit of judging a storms fate by each change in the satellite frame.
Member Since: July 8, 2005 Posts: 259 Comments: 24578
Anyone here agree on this...



and...

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1872. barbamz

Have a nice Sunday everone! I don't have much time in the moment, but I follow your fate with 95L and wish you all the best with it. Greetings from Germany with very pleasant summer weather these days.
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1871. Grothar
Quoting 1869. yonzabam:


I'm surprised crows aren't extinct.


LOL.
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wow!!! here come invest 96L..VERY NICE TROPICAL WAVE!!
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Quoting 1863. flcanes:
Im taking next TWO is going to be 50%.
And yes, I will eat crow if necessary.


I'm surprised crows aren't extinct.
Member Since: July 20, 2008 Posts: 0 Comments: 3013
Good morning, everyone. Afternoon, Barbamz and VR. Evening, Aussie. Starting the day off at a warm 74 that feels like 78 degrees. There's a 50% chance of rain, but none in sight. I live in hope. *G*

Breakfast's on the sideboard: egg whites and salmon on toasted whole wheat English muffin with a tomato, whole grain waffles with cherry sauce, apple-bacon pancakes with cider syrup, lemon cranberry muffins, turkey bacon, extra lean ham, fresh fruit and choice of orange or apple juice. Everything is heart healthy, all in honor of Grothar. Enjoy!
Member Since: Posts: Comments:

Quoting 1859. GeoffreyWPB:
starting to lift wnw a slow down might be coming.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
1866. Grothar
Quoting 1859. GeoffreyWPB:



That's old.
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1865. flcanes
Quoting 1859. GeoffreyWPB:

*gulps*
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1864. Grothar
GFS ensemble models.





As posted earlier, the dynamic and statistical models:




The Global models: (These are the ones I am favoring for now)

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1863. flcanes
Im taking next TWO is going to be 50%.
And yes, I will eat crow if necessary.
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Quoting 1854. SLU:
Now up to T2.0. All we need now is for confirmation of a closed LLC and TD #3 will join us.

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

Interesting

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1861. pcola57
A little shower here for those who missed their Saturday baths.. :)

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Quoting 1854. SLU:
Now up to T2.0. All we need now is for confirmation of a closed LLC and TD #3 will join us.

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

Okay impressive it looks to be getting ready to organize it self and fire up some convection later today. It still need to slow down to 15-20mph before there can be any west winds. But it looks to be on its way.
Member Since: May 25, 2012 Posts: 0 Comments: 2043
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Looks more impressive here. Link RGB Loop
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look at the vorticity back of invest 95L its looking good this morning to
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Here is the wind shear chart notice the tiny ULAC where 95L is.

Member Since: May 25, 2012 Posts: 0 Comments: 2043
the damage has been done 94 represented itself well.
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1854. SLU
Now up to T2.0. All we need now is for confirmation of a closed LLC and TD #3 will join us.

07/1145 UTC 9.1N 41.1W T2.0/2.0 95L
Member Since: July 13, 2006 Posts: 13 Comments: 5367

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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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