ATL: TEN - Post-Tropical - Discussion

[TheStormExpert]

looks like some convection is on the increase. This would likely become Irma instead of Harvey. I just don't like the sound of that name..."Irma"

Neither do I, Irma sounds way more threatening than Irene did. In fact it's probably the most threatening name on this years list of names.

[RL3AO]

Conditions don't look unfavorable in the Bahamas when it gets there, but the models don't develop it. On the other hand, the conditions were favorable with Gert too and the models didn't develop it. Watch this one very closely.

[gatorcane]

Another view of the convection blowup - deepest convection we have seen so far:

[tgenius]

While it is still way too early I think this one might be the one to worry about for CONUS.. i'm watching it like a hawk; Andrew's 25th anniversary is a week away too!

[OuterBanker]

The TUTT in the Eastern Bahamas is definitely moving west. The upper-low north of 92L with the shear the models think could severely disruption 92l is slowly moving SSW. Doesn't seem to be making that much progress:

What an excellent example of a TUTT and great instructional moment.
You can see how the Haiti/DR shredding machine doesn’t even phase a TUTT. While it would shred apart a tropical system. Mets, correct me if I’m wrong.

[Bocadude85]

If you read the discussion on potential tropical cyclone 9 you can see that the NHC isn't putting much faith into the Euro or GFS as far as intensity goes...I would assume we can draw the same conclusions with 92L as well.

[Aric Dunn]

Should have chances go up again at 2 pm and see advisories by tomorrow morning.

[SouthFLTropics]

If you read the discussion on potential tropical cyclone 9 you can see that the NHC isn't putting much faith into the Euro or GFS as far as intensity goes...I would assume we can draw the same conclusions with 92L as well.

From the 11:00AM discussion on PTC 9 in regards to NHC's thinking of the model output currently:

The system is in an area of moderate easterly vertical shear, and
the large-scale models suggest that light/moderate shear should
continue through the forecast period. This seems favorable for
strengthening, and the SHIPS and LGEM models show slow, but steady,
intensification. However, the GFS and ECMWF models forecast the
system to degenerate to an easterly wave over the central Caribbean
Sea, possibly due to dry air entrainment. The intensity forecast
follows the trend of the SHIPS/LGEM models, but it respects the
GFS/ECMWF forecasts by being on the low side of the intensity
guidance envelope.

[sma10]

The TUTT in the Eastern Bahamas is definitely moving west. The upper-low north of 92L with the shear the models think could severely disruption 92l is slowly moving SSW. Doesn't seem to be making that much progress:

Really impressed also with the large blowup of showers that the TUTT is causing in its interaction with a wave. If it holds together, it's going to bring quite a rainy day to the peninsula on Saturday.

[Blown Away]

Should have chances go up again at 2 pm and see advisories by tomorrow morning.

Lofty goal...

91L has no support from GFS and some Euro support near CA, but not in next 72 hours, but NHC still started advisories...

[Bocadude85]

If you read the discussion on potential tropical cyclone 9 you can see that the NHC isn't putting much faith into the Euro or GFS as far as intensity goes...I would assume we can draw the same conclusions with 92L as well.

From the 11:00AM discussion on PTC 9 in regards to NHC's thinking of the model output currently:

The system is in an area of moderate easterly vertical shear, and
the large-scale models suggest that light/moderate shear should
continue through the forecast period. This seems favorable for
strengthening, and the SHIPS and LGEM models show slow, but steady,
intensification. However, the GFS and ECMWF models forecast the
system to degenerate to an easterly wave over the central Caribbean
Sea, possibly due to dry air entrainment. The intensity forecast
follows the trend of the SHIPS/LGEM models, but it respects the
GFS/ECMWF forecasts by being on the low side of the intensity
guidance envelope.

12Z SHIPS and LGEM have 92L as a strengthening TS at 120 hours.

[northjaxpro]

I wouldn't be surprised to see recon go out to this one by tomorrow if it continues to organize

Yes, I agree.

[Aric Dunn]

Should have chances go up again at 2 pm and see advisories by tomorrow morning.

Lofty goal...

91L has no support from GFS and some Euro support near CA, but not in next 72 hours, but NHC still started advisories...

That is always the problem with models. they are only as good as the quality of the data that is inputed. I have been extremely perplexed with the amount of forecasting made in the short term range from the NHC and many others instead of actually following the trends. Gert is a perfect example. no support from models and they just kept putting it off putting it off when it was clearly classifiable at least 2 days before the forst advisory.

for TC genesis ot is always prudent to do a series of short term analysis and forecast than to strictly look at a model and say "well models do not develop it at all ever so no need to pay attention" or the "next please" mentality will lead to failure.

[wxman57]

One problem may be PTC Nine (Harvey-to-be). If we get a strong TS or hurricane passing north of Honduras next Monday while this disturbance is in the Florida Straits, then it will be encountering lots of westerly shear from Harvey's outflow.

[p1nheadlarry]

The TUTT in the Eastern Bahamas is definitely moving west. The upper-low north of 92L with the shear the models think could severely disruption 92l is slowly moving SSW. Doesn't seem to be making that much progress:

https://s12.postimg.org/7vg5d2b3h/wv-animated.gif

What an excellent example of a TUTT and great instructional moment.
You can see how the Haiti/DR shredding machine doesn’t even phase a TUTT. While it would shred apart a tropical system. Mets, correct me if I’m wrong.

I'm not a met but they are in the 200mb level, that's up there.

[Aric Dunn]

convection has persisted since yesterday and there are clear signs of a closed circ ( quite prevalent actually ). this by definition is classifiable.

[Bocadude85]

One problem may be PTC Nine (Harvey-to-be). If we get a strong TS or hurricane passing north of Honduras next Monday while this disturbance is in the Florida Straits, then it will be encountering lots of westerly shear from Harvey's outflow.

What if Harvey is not as strong as expected or moves inland into Honduras? Do you see a tropical storm threat to S.Fla?

[SouthFLTropics]

convection has persisted since yesterday and there are clear signs of a closed circ ( quite prevalent actually ). this by definition is classifiable.

By the strictest definition yes...it is classifiable. I think they only pulled the trigger on PTC 9 since it will be the first to affect land masses and population centers. 92L currently poses no threat so they feel there is no need to classify as of yet. Just my 2 cents.

[wxman57]

One problem may be PTC Nine (Harvey-to-be). If we get a strong TS or hurricane passing north of Honduras next Monday while this disturbance is in the Florida Straits, then it will be encountering lots of westerly shear from Harvey's outflow.

What if Harvey is not as strong as expected or moves inland into Honduras? Do you see a tropical storm threat to S.Fla?

That's possible. Most models and ensemble members indicate dissipation east of Florida. Regardless, I don't think this will be a very large storm. More likely a rainfall threat.

[CrazyC83]

000
URNT15 KNHC 171557
AF303 0109A INVEST HDOB 04 20170817
154700 1728N 06330W 4095 07450 0433 -136 -206 123016 018 /// /// 03
154730 1728N 06328W 4095 07447 0430 -139 -212 117018 018 /// /// 03
154800 1728N 06326W 4098 07440 0428 -136 -220 118018 018 /// /// 03
154830 1727N 06324W 4098 07439 0427 -140 -272 119018 018 /// /// 03
154900 1727N 06321W 4098 07440 0427 -135 -289 117017 018 /// /// 03
154930 1726N 06319W 4098 07441 0427 -135 -298 118016 017 /// /// 03
155000 1726N 06317W 4100 07439 0429 -135 -303 114019 021 /// /// 03
155030 1725N 06314W 4094 07447 0427 -137 -305 113020 020 /// /// 03
155100 1725N 06312W 4102 07433 0428 -135 -309 115018 019 /// /// 03
155130 1724N 06309W 4098 07441 0428 -135 -311 114018 018 /// /// 03
155200 1724N 06307W 4099 07438 0428 -137 -310 111019 021 /// /// 03
155230 1723N 06305W 4100 07438 0428 -136 -303 109019 020 /// /// 03
155300 1723N 06302W 4098 07442 0430 -139 -309 110020 021 /// /// 03
155330 1722N 06300W 4099 07438 0428 -136 -341 112022 022 /// /// 03
155400 1722N 06257W 4098 07439 0427 -135 -340 113023 023 /// /// 03
155430 1721N 06255W 4098 07440 0428 -138 -341 114022 023 /// /// 03
155500 1721N 06252W 4101 07435 0428 -137 -356 113022 023 /// /// 03
155530 1720N 06250W 4097 07442 0428 -140 -372 115022 023 /// /// 03
155600 1720N 06247W 4099 07438 0427 -140 -369 115023 023 /// /// 03
155630 1719N 06244W 4099 07438 0427 -135 -368 115023 023 /// /// 03
$$
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