ATL: FOUR - Remnants - Discussion

[Hurricaneman]

I could see this being a 60mph ts before shear and dry air get it, but what if it heads closer to the islands than predicted or modeled and somehow stays away from the dry air or gets less dry air

[USTropics]

i been reading we could see 94l disactive by 5am or 2pm thur

5AM Thursday is in 6 hours, I don't see any reason why this won't slowly organize at least for the next 24 hours. There will be some dry air entrainment, but that really won't be detrimental until it runs into that SW shear in 48 hours imo.

[MississippiWx]

Ehh, it still looks quite sheared to me. I see a vigorous MLC displaced to the west of the surface center, which is on the eastern edge of the convection. It's possible we see a center reformation under the MLC, but I've been burned so many times thinking these sheared blobs will intensify, that I am very hesitant to think this will be any different...

Tend to agree with you. These blobs are very deceiving at night on nothing but IR imagery. I like to see low level bands coming into the system to help me feel better about organization. These mid level blobs are not capable of having those bands.

It's a very small system, so it's not impossible for it to be more organized/stronger than we think. However, experience with this tells me the actual center of the low is still on the eastern edge of convection. Sucks to have limited data.

[Alyono]

the ASCAT showed this is nowhere near TS intensity

[MississippiWx]

the ASCAT showed this is nowhere near TS intensity

ASCAT also missed the western half of the circulation where the strongest convection is located. Would have liked to see it too.

[TheStormExpert]

Well it did it! 94L finally became a classifiable TC although just a depression I still think it'll have enough time to attempt at making a run at becoming Don before the SAL, dry air, and shear catch-up to it. What's even more impressive is it developed in a very suppressed phase of the MJO which makes me wonder what we could be dealing with if the MJO had been favorable.

[floridasun78]

wow their enough data to make it td what did nhc saw to make it td alot say low was expose to east storm area?

[blp]

Looks to be in a nice pocket for now. Should be Ok next 24hrs or so.

[Alyono]

MU insists this will be a wave by 12Z

Something like that did happen with Tropical Depression Two back in 2000. Looked like a TS and then 3 hours later, it was an open wave

[TheStormExpert]

Worst SAL outbreak so far this season is on the heels of TD#4.

 https://twitter.com/ryanmaue/status/882811517141471232

[hurricanehunter69]

Check out our TC's presentation on water vapor imagery tonight http://www.ssd.noaa.gov/goes/east/tatl/flash-wv.html The storm is not as small as most think and is growing larger and healthier by the hour. The storm has obviously fought off the SAL to it's east very well. I think we have a very good chance of having a TS tomorrow morning if not already. I'm also gaining a little more confidence in it's future and having an entity to track next week. Look for the storm to track a little more westerly and have a little less interaction with the TUTT low off to it's northwest.

[Digital-TC-Chaser]

Nope, it was based on that ASCAT. I said TC not TS (aka a tropical depression).

There is nothing over 30kts on that ascat,to my knowledge TC aka TD is 34kts.
But givin the low bias of ascats yeah likely is a td

TD is a tropical cyclone (warm-core, non-frontal, synoptic scale cyclone with organized deep convection and a closed surface wind circulation about a well-defined center) with winds LESS THAN 34 kt. This system has a well-defined circulation center and organized deep convection, so it is a TD.

Very authoritarian post ,been following cyclones most of my life in all basins .
I like to see better than 20kts on the ascat it was (marginal) @best.

I would prefer to see 30's (yellow). At-least wrapping around the centre before the upgrade.


Most tropical depressions have maximum sustained winds between 25 and 35 mph.
This ascat shows 23mph so it was marginal full stop.

[AutoPenalti]

Wow, this actually became a depression. lol.

[NotoSans]

Different TCWCs have different criteria for upgrades. Here in the Atlantic, the NHC defined a tropical depression as 'a tropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) is 33 kt (38 mph or 62 km/hr) or less.', with no minimum requirement in the maximum sustained wind speed. With a well-defined center, a closed circulation and well-organized deep convection, this upgrade is reasonable according to the NHC's criterion. Of course, this system may not be upgraded by other TCWCs responsible for other basins because of different criteria.
Also, it is important to note that the ASCAT pass missed the western quadrant of the system where the convection locates. For this type of system, the maximum winds are usually under the convection, and I don't think the ASCAT pass have captured the maximum winds.

[floridasun78]

i think nhc should have wait untill thur after noon to do this we see if storm stay with 94l/td see how dry air come into play but nhc are pro we not

[txwatcher91]

There is nothing over 30kts on that ascat,to my knowledge TC aka TD is 34kts.
But givin the low bias of ascats yeah likely is a td

TD is a tropical cyclone (warm-core, non-frontal, synoptic scale cyclone with organized deep convection and a closed surface wind circulation about a well-defined center) with winds LESS THAN 34 kt. This system has a well-defined circulation center and organized deep convection, so it is a TD.

Very authoritarian post ,been following cyclones most of my life in all basins .
I like to see better than 20kts on the ascat it was (marginal) @best.

I would prefer to see 30's (yellow). At-least wrapping around the centre before the upgrade.


Most tropical depressions have maximum sustained winds between 25 and 35 mph.
This ascat shows 23mph so it was marginal full stop.

Keep in mind the western half of the storm wasn’t sampled by that pass, so it’s entirely possible that higher winds would be there. With a closed LLC, persistent convection and apparent organization continuing on IR it definitely meets TD criteria.

[Aric Dunn]

NRL site is not updating .. anyone else have a site with the same microwave images ?

[Digital-TC-Chaser]

GLOBAL MODEL DATA TIME 00UTC 06.07.2017



TROPICAL DEPRESSION 04L ANALYSED POSITION : 12.7N 38.0W



ATCF IDENTIFIER : AL042017

Mets office .

VERIFYING TIME POSITION STRENGTH TENDENCY

-------------- -------- -------- --------

00UTC 06.07.2017 12.7N 38.0W WEAK

12UTC 06.07.2017 BELOW TROPICAL STORM STRENGTH

[Digital-TC-Chaser]

NRL site is not updating .. anyone else have a site with the same microwave images ?

Try here AMSU's maybe in.

http://www.usno.navy.mil/FNMOC/tropical-applications

[AubreyStorm]

As of 0500 AM AST Thu Jul 06 (Advisory # 2)
Maximum Sustained Winds: 25 knots; 30 mph
Minimum Central Pressure: 1008 mb
Located at: 13.2N 40.0W
Movement: west-northwest at 15 knots; 17 mph