2018 Tropics: Global Model Runs Discussion (Out to day 16)

[weathaguyry]

12z GFS bringing a TS near Long Island on Saturday Night, High res Euro charts also show 50mph for Long Island on Sunday

[Alyono]

Not sure this is tropical

[weathaguyry]

Not sure this is tropical

Yes, on second thought it’s probably some sort of messy hybrid thing that probably won’t get classified

[TheStormExpert]

Doesn’t even look Subtropical.

[chaser1]

While there is no implicit model support to to suggest tropical development throughout the MDR or the Caribbean, I see hints to suggest we could well see a tropical storm develop in the Caribbean 6 -9 days from now.

I think I see a subtle trends for the 150hr. - 220 hr. period where the 200 mb flow from just east of the Lesser Antilles west into the Southern Caribbean could indicate a more relaxed and anticyclonic flow. Currently strengthening W. Atlantic surface to mid level high pressure looks to squelch potent tropical waves as well as any semblance of an Atlantic ITCZ for the foreseeable future, there appears to be a window where I can see another small tropical cyclone make an attempt at genesis within a relative small "goldilocks zone" in that 6-9 day time frame.

Present indications are that the very stout 500mb W. Atlantic high pressure ridge will continue to slowly shift west over time. Toward the end of this time frame there looks to be indications for height falls extending from the Eastern Gulf southward into the Central & W. Caribbean where I believe the Southern extension of an increasingly active tropical wave will be moving through around that period of time (this potentially corroborated by an increase in forecast 500 mb vorticity in the W. Caribbean around the 29th). The 12Z GFS 500 mb 48 hr. forecast trend starting at around the 150 hr. time frame seems to bear out the model trends toward the falling mid level heights just east of and into the Caribbean. I believe that the orientation at that time of the strong W. Atlantic surface ridge will then result in a more southeasterly surface flow. This in combination with the already tight pressure gradient as a result of the strong high pressure well to the north, in tandem with a sharp tropical wave and falling mid level heights in the Caribbean.... will ultimately present a reasonable window for tropical development assuming adequate upper level conditions. Ordinarily I would not perceive present forecast upper level conditions particularly favorable for any broad slow moving tropical system in the Caribbean to develop. One earmark of this season however seems to be the genesis of small compact tropical cyclones. To me very subtle indications of these mid to long range models, hint toward that type of tropical formation could occur in the Caribbean during the upcoming July 26-29 timeframe. Given the long-shot that i'm correct, I highly doubt that any model would even hint toward development much beyond 60 hr.'s (and doubtful that the EURO would at all) given the smallish nature of tropical cyclone that I think could develop around that time.

[CyclonicFury]

:uarrow: Doesn’t even look Subtropical.

FSU phase diagram does analyze it as symmetric warm core FWIW.

[Kingarabian]

There could be a window for development by the end of this week since the 12z Euro has favorable VP200 anomalies over the GOM and off the east coast by days 2 and 6 of its 10 days forecast.

[Siker]

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 72 HOURS
FORECAST POSITION AT T+ 72 : 34.3N 77.1W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 21.07.2018 72 34.3N 77.1W 1010 32
0000UTC 22.07.2018 84 35.6N 74.3W 1005 42
1200UTC 22.07.2018 96 39.2N 73.8W 1000 43
0000UTC 23.07.2018 108 CEASED TRACKING

[Steve]

Yeah. Some of the energy is in the northern Gulf today just off the MS Coast. I think that merges with the front and spins up in a few days. Interestingly, the GFS follows that front with a big low pressure which drops a piece back toward the Gulf and retrogrades it toward Texas. It doesn't look like much organization, but it's probably something to watch early next week

[SoupBone]

Yeah. Some of the energy is in the northern Gulf today just off the MS Coast. I think that merges with the front and spins up in a few days. Interestingly, the GFS follows that front with a big low pressure which drops a piece back toward the Gulf and retrogrades it toward Texas. It doesn't look like much organization, but it's probably something to watch early next week

Of course it does...

[beoumont]

:think: While there is no implicit model support to to suggest tropical development throughout the MDR or the Caribbean, I see hints to suggest we could well see a tropical storm develop in the Caribbean 6 -9 days from now.

I think I see a subtle trends for the 150hr. - 220 hr. period where the 200 mb flow from just east of the Lesser Antilles west into the Southern Caribbean could indicate a more relaxed and anticyclonic flow. Currently strengthening W. Atlantic surface to mid level high pressure looks to squelch potent tropical waves as well as any semblance of an Atlantic ITCZ for the foreseeable future, there appears to be a window where I can see another small tropical cyclone make an attempt at genesis within a relative small "goldilocks zone" in that 6-9 day time frame.

Present indications are that the very stout 500mb W. Atlantic high pressure ridge will continue to slowly shift west over time. Toward the end of this time frame there looks to be indications for height falls extending from the Eastern Gulf southward into the Central & W. Caribbean where I believe the Southern extension of an increasingly active tropical wave will be moving through around that period of time (this potentially corroborated by an increase in forecast 500 mb vorticity in the W. Caribbean around the 29th). The 12Z GFS 500 mb 48 hr. forecast trend starting at around the 150 hr. time frame seems to bear out the model trends toward the falling mid level heights just east of and into the Caribbean. I believe that the orientation at that time of the strong W. Atlantic surface ridge will then result in a more southeasterly surface flow. This in combination with the already tight pressure gradient as a result of the strong high pressure well to the north, in tandem with a sharp tropical wave and falling mid level heights in the Caribbean.... will ultimately present a reasonable window for tropical development assuming adequate upper level conditions. Ordinarily I would not perceive present forecast upper level conditions particularly favorable for any broad slow moving tropical system in the Caribbean to develop. One earmark of this season however seems to be the genesis of small compact tropical cyclones. To me very subtle indications of these mid to long range models, hint toward that type of tropical formation could occur in the Caribbean during the upcoming July 26-29 timeframe. Given the long-shot that i'm correct, I highly doubt that any model would even hint toward development much beyond 60 hr.'s (and doubtful that the EURO would at all) given the smallish nature of tropical cyclone that I think could develop around that time.

Now that is some really subdued optimism.

[Steve]

Yeah. Some of the energy is in the northern Gulf today just off the MS Coast. I think that merges with the front and spins up in a few days. Interestingly, the GFS follows that front with a big low pressure which drops a piece back toward the Gulf and retrogrades it toward Texas. It doesn't look like much organization, but it's probably something to watch early next week

Of course it does...

What? Do you prefer it stay in the upper 100's for the rest of the summer? I think a break from the heat by way of a retrograding piece of an Upper Level Low would probably spell relief. But that's me. I love it hot, but 107/108 in Dallas just seems up there for this year. Austin gets to like 106 this weekend. That's freaking hot.

[Siker]

Though the tropical-ness of the low developing off the East Coast is in question, it certainly looks to be impactful. 12z UKMET:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 42 HOURS
FORECAST POSITION AT T+ 42 : 33.0N 77.8W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 21.07.2018 48 34.4N 75.7W 1008 38
0000UTC 22.07.2018 60 37.2N 73.1W 996 53
1200UTC 22.07.2018 72 41.4N 72.6W 994 43
0000UTC 23.07.2018 84 45.8N 72.8W 1011 20
1200UTC 23.07.2018 96 CEASED TRACKING

[weathaguyry]

I will be watching closely from southern Long Island, could there be any storm surge threat?

[TheAustinMan]

:uarrow: I will be watching closely from southern Long Island, could there be any storm surge threat?

Any time there's a low-pressure area kicking up waters with gusty winds, there will be a storm surge threat. For what it's worth, WW3 global shows 9ft waves (wave heights, not storm surge) making it to Long Island. NDFD grids show about the same with 6-9 ft waves arriving Sunday morning. Waiting to see what ESTOFS shows for storm surge specifically, but I imagine probably in the ballpark of 0.5-1.5ft for storm surge (tide dependent). Keep an eye on local bulletins for the most accurate information.

The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the NHC and NWS.

[weathaguyry]

:uarrow: I will be watching closely from southern Long Island, could there be any storm surge threat?

Any time there's a low-pressure area kicking up waters with gusty winds, there will be a storm surge threat. For what it's worth, WW3 global shows 9ft waves (wave heights, not storm surge) making it to Long Island. NDFD grids show about the same with 6-9 ft waves arriving Sunday morning. Waiting to see what ESTOFS shows for storm surge specifically, but I imagine probably in the ballpark of 0.5-1.5ft for storm surge (tide dependent). Keep an eye on local bulletins for the most accurate information.

The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the NHC and NWS.

Thanks for the info!!!

[MGC]

18Z NAM has a 998mb low just off mouth of Chesapeake Bay on Saturday afternoon tracking north into the Delmarva Peninsula.....MGC

[Hurricaneman]

The 12zgfs seems to show something forming in the Bahamas at 300hrs and moving into the Gulf, I wouldn’t believe it yet as it could be a phantom storm but this is the same model that sniffed out Alberto around the same timeframe back in May and was the first model to sniff out Beryl and Chris

If it isn’t on the 18zGFS then it’s most likely a phantom.

It also has an interesting trough between Bermuda and Puerto Rico so we’ll have to see if that’s retained because it has been on the last few GFS runs

[Hurricaneman]

18zGFS doesn’t have the GOM storm but does have some subtropical looking thing breaking off the front in the central Atlantic at about 300 hrs but completely drops it after 348 hrs so that’s something I’m going to watch for in the models the next few days as the GFS has had this feature in the long range the last 3 runs

[chaser1]

The 12zgfs seems to show something forming in the Bahamas at 300hrs and moving into the Gulf, I wouldn’t believe it yet as it could be a phantom storm but this is the same model that sniffed out Alberto around the same timeframe back in May and was the first model to sniff out Beryl and Chris

If it isn’t on the 18zGFS then it’s most likely a phantom.

It also has an interesting trough between Bermuda and Puerto Rico so we’ll have to see if that’s retained because it has been on the last few GFS runs

I think this is the same wave that I was hedging might sneak up on the Lesser Antilles and possibly develop just east of there or in the Caribbean between the 26th-29th of this month. Interestingly, if you take a real close look at this a.m.'s visible satellite, you'll see a low latitude - low level spin
right at about 7.8N & 39.6W. It could very well just go "poof" but I doubt that the present easterly surge will allow it to gain much latitude as it approaches 50W-60W.