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Barbara weakening, 91E slowly sorganizing

By: wxchaser97 , 12:20 PM GMT on May 30, 2013

Tropical depression (TD) Barbara continues to be on the weakening phase. The low level circulation has most likely continued to decay, can't get a recent ASCAT/OSCAT pass, and the spin has slowed. There doesn't look to have been much in the way of TS winds recorded in the last few hours as well. Convection had been waning more until a couple hours ago when there was a burst of convection. This convective burst is already fading somewhat. Also the circulation looks to be on the southern part of this burst, not in the middle. However, it has almost made it into the BOC so there is a chance that it re-intensifies some. SST's are warm and shear is low in the far southern BOC, but the air isn't very moist. Even if it does reform, it won't have long to live. If it goes much farther north it would get destroyed by strong wind shear. However it is likely it meanders in the BOC and eventually makes landfall on the Mexican mainland. If Barbara somehow strengthened and used its resources to the fullest, I can only see it becoming a minimal tropical storm. It shouldn't pose much of a threat to Mexico wind wise. Rainfall will still be a problem regardless of development. Heavy rain and flooding is almost always a problem with any system that hits Mexico and surrounding areas in the Caribbean. The latest storm info, satellite, and microwave images can be found below. There won't be a big analysis like the last blog as Barbara is just a little depression.

2:00 AM PDT Thu May 30
Location: 17.8°N 93.9°W
Moving: N at 8 mph
Min pressure: 1000 mb
Max sustained: 35 mph

Figure 1: Satellite image of Barbara.

Figure 2: Microwave image of Barbara.

Invest 91E has been around for a wile now. I have been more focused on Barbara due to its threat to Mexico. Now that Barbara has calmed down some I can look into 91E some more. It looks like there is a decent circulation, but convection keeps on getting sheared away before it can get very organized over the center. Below is the current ATCF info, satellite image, and ASCAT pass.

EP, 91, 2013053006, , BEST, 0, 135N, 1115W, 30, 1006, DB, 0, , 0, 0, 0, 0, 1010, 150, 25, 0, 0, E, 0, , 0, 0, INVEST, M,

Figure 3: Satellite image of 91E showing not much convection.

Figure 4: Most recent ASCAT image of 91E showing a defined circulation.

What we have here is a pretty well defined surface circulation according to ASCAT. Winds are increasing and there are wind barbs in nearly every direction around the center. There is also spin on the visible and infrared satellites. Microwave images show a good mid level and decent low level circulation too. Pressures are also dropping per ATCF indicating a strengthening system. T #'s are at 1.5 which is in the TD range. However, it still has a long way to go to being a tropical cyclone.

Of course, you need organized convection over a well defined closed circulation to be classified. We are near the closed circulation, but organized convection is hard to come by. This is due to some dry air and pretty strong easterly wind shear. There was a brief period where convection got over the low level center, but it was quickly sheared away. Shear is slowly decreasing, but I think it will still stay in the unfavorable to only slightly favorable at best for a while. SST's are modest, but they could be better. They won't become too much of a factor until later. Models aren't indicating much development of 91E. I agree with them that 91E will likely not develop. There is a small chance, but its window of opportunity until it hits more unfavorable conditions isn't too long from now. I give 91E a 30% chance of tropical development in the the next 48hrs. My tracking map for Barbara and 91E can be found below.

Figure 5: My forecast map for Barbara and 91E.

Have a great Thursday everyone and I will probably have another update this evening.

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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3. WunderAlertBot (Admin)
6:03 AM GMT on June 20, 2013
wxchaser97 has created a new entry.
2. trHUrrIXC5MMX
3:04 AM GMT on June 15, 2013
Pretty nice thing you got going there Isaac.
Member Since: December 31, 1969 Posts: Comments:
1. wxchaser97
1:59 PM GMT on May 30, 2013
Barbara has survived, barely. The circulation has made it into the BOC. Lets see what it does.
Member Since: December 31, 1969 Posts: Comments:

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About wxchaser97

I'm a CMU Honors student and love meteorology and extreme weather. I've been fascinated by weather since I was 5, and plan on becoming a meteorologist

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