ATL: INVEST 92L - Discussion

[WeatherGuesser]

THEY COULD BECOME MORE

The word is could, not will.

Big difference.

Folks need to chill.

[wxman57]

Wxman57, I respectfully disagree. Conditions should be favorable in 2-3 days time. I give 92L a 70% chance of becoming a hurricane.

Based upon what? All data indicate moderate shear (except briefly in 36-48hrs), dry air in mid levels and warm air aloft. Where are the favorable conditions?

Based upon NHC official wording in the TWO. With all due respect, do you suggest otherwise?

They're not saying it will develop, just that at least the shear will drop in a few days (as I said). Other conditions still are quite hostile.

[HurrMark]

I agree with wxman57...conditions are more or less like you would see in the spring...I also feel the season is about to shut down...maybe a few more storms in the subtropics harmlessly moving out to sea (not an official forecast).

Looking at a map of this season's storms, and it is uncanny to think how we were able to have as many storms as we did. Other than Ernesto, not a single hurricane developed in the tropics. The only season in recent years where that occurred was 1997, which had half the number of tropical cyclones we have had so far. The season isn't over yet, but this is yet another reason why I personally feel there are some major climatological changes going on that are actually going to benefit the US in terms of tropical cyclone impacts over the long haul.

[jinftl]

Dr. Jeff Masters not sounding too bullish on this either - in line with NHC outlook pretty much. Models really not jumping on this, except the NOGAPS which only indicates weak development. Overall, something to keep an eye on, but nothing to worry about at this time.

A tropical wave (Invest 92L) entering the Lesser Antilles Islands is moving west at 15 mph, and is bringing heavy rain showers and gusty winds to the islands today. The wave is under a moderate 10 - 20 knots of wind shear, and has only a small amount of heavy thunderstorm activity, due to a large area of dry air surrounding the system. The amount of heavy thunderstorm activity has decreased since Saturday.

The latest SHIPS model forecast predicts shear will fall to the 10 - 15 knot range Monday through Wednesday, which will favor development. However, the atmosphere over the Caribbean is unusually dry and stable, and this will make it difficult for 92L to organize quickly. 92L will bring heavy rain showers to the Dominican Republic and Haiti on Wednesday, Jamaica and eastern Cuba on Thursday, the Cayman Islands and Central Cuba on Friday, and Mexico's Yucatan Peninsula and Western Cuba on Saturday. The 06Z run of the NOGAPS models indicates some weak development of 92L once it reaches the Western Caribbean, but none of the other reliable models develop the system. In their 8 am EDT Tropical Weather Outlook, NHC gave the wave a 20% of developing into a tropical depression by Tuesday morning. A hurricane hunter aircraft is on call for Monday afternoon to investigate the storm, if necessary.

[LarryWx]

ALTHOUGH UPPER-LEVEL WINDS ARE CURRENTLY UNFAVORABLE
FOR DEVELOPMENT TO OCCUR...THEY COULD BECOME MORE CONDUCIVE IN A
FEW DAYS. so wxman57 vs nhc let see what met is right

With all due respect to Mr. Stewart (and I assure you that I respect him for his vast knowledge, skills, and experience), my experience over the years is that he does have some tendency toward his TWO's being worded a bit more optimistically toward development possibilites vs. most of the other NHC forecasters. That being said, I'm not saying he's anywhere close to JB in that regard. Regardless, his TWO says only that "they could become more conducive." Also, even if they were to become more conducive, that still is far from saying it will likely develop.

By the way, SHIPS typically already assumes a tropical cyclone already exists, which isn't the case here. That model overstrengthens trop. disturbances numerous times a season.

[HurricaneAndrew92]

In 36-48hrs, this Invest should start to get its act together. What happens after that, I'm clueless.

[Sanibel]

From the looks of it conditions are even worse than August for these struggling Lows.

[LarryWx]

In 36-48hrs, this Invest should start to get its act together. What happens after that, I'm clueless.

I respect your opinion. However, even in the best of setups, the eastern Caribbean is very rarely where a disturbance starts getting its act together based on history. So, I just don't see it. Then again, one never knows for sure.

[HurricaneAndrew92]

In 36-48hrs, this Invest should start to get its act together. What happens after that, I'm clueless.

I respect your opinion. However, even in the best of setups, the eastern Caribbean is very rarely where a disturbance starts getting its act together based on history. So, I just don't see it. Then again, one never knows for sure.

No, no. I'm just saying that it will try, maybe hit TD, but I don't know.

[chrisjslucia]

No idea what will happen down the line but this invest is finally bringing us (St Lucia) some rain and forcing the temperature down a little. After weeks of great heat, blue skies and DRY weather (virtually no rain since Isaac on August 22nd) today is overcast, dark at times, some rain but not yet a great deal, occasional thunder and mercifully it is a little cooler. Just about everyone in the Eastern Caribbean is likely to be happy if they are within the rainfall area.

[chaser1]

In 36-48hrs, this Invest should start to get its act together. What happens after that, I'm clueless.

I respect your opinion. However, even in the best of setups, the eastern Caribbean is very rarely where a disturbance starts getting its act together based on history. So, I just don't see it. Then again, one never knows for sure.

Just for the sake of adding to the discussion, I think that the present easterly shear will hold any development at bay for the time being. The fact that the system will have its convergence further hindered by proximity to S. American does not help either. While downstream upper air conditions do appear to be less hostile in the Southwestern Caribbean, I would best describe that as "relative" to the present. Visible satellite would indicate some nice low level rotation around 55W, but other than warm SST's all that I can see that is working in favor of 92L developing to a depression within 96 hours is "Climotology". The fact that NHC decided to bump a 48 hr. forecast from 10% to 20% for any tropical system in the tropics during an active year to me is negligable.

[Gustywind]

First appearence on SSD...

16/1145 UTC 12.5N 54.5W TOO WEAK 92L

[Dean4Storms]

I'd be a bit surprised if this develops with the shear, dry air and little model support. About the only thing 92L has going for it is very warm SST's out ahead of it in the western Carib. It could find a little window and give it a shot but it is going to struggle.

[CourierPR]

Joe Bastardi posted a Weather Bell loop on Twitter and commented that they will be watching 92L for possible development later this week in the Western Caribbean.

[HurricaneAndrew92]

Track

[cycloneye]

2 PM TWO:

AN ELONGATED AREA OF LOW PRESSURE LOCATED ABOUT 325 MILES EAST OF
THE LESSER ANTILLES IS PRODUCING DISORGANIZED SHOWERS AND A FEW
THUNDERSTORMS. ALTHOUGH UPPER-LEVEL WINDS ARE CURRENTLY UNFAVORABLE
FOR DEVELOPMENT TO OCCUR...THEY COULD BECOME MORE CONDUCIVE IN A
FEW DAYS. THIS SYSTEM HAS A LOW CHANCE...20 PERCENT...OF BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES WESTWARD AT
AROUND 15 MPH. REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINS AND
SQUALLS COULD AFFECT PORTIONS OF THE LESSER ANTILLES TODAY THROUGH
MONDAY.

[cycloneye]

18z Best Track

AL, 92, 2012091618, , BEST, 0, 135N, 559W, 20, 1011, LO

[HurricaneAndrew92]

18z Best Track

AL, 92, 2012091618, , BEST, 0, 135N, 559W, 20, 1011, LO

Why the change from disturbance to Low? Better defined circulation near the center?

[cycloneye]

18z Best Track

AL, 92, 2012091618, , BEST, 0, 135N, 559W, 20, 1011, LO

Why the change from disturbance to Low? Better defined circulation near the center?

There is a weak low pressure in the area even if is not with a good deal of convection at this time. The LO designation doesn't mean that it will develop anytime soon if it does at all.

[blp]

I can see why the reliable models are not interested on this. Mid level voticity is over the islands outracing lower level vorticity. Let's see if it slows down and stacks in W. carribean.

http://www.ssd.noaa.gov/PS/TROP/floaters/92L/imagery/vis-animated.gif