2017 Global Model Runs Discussion (Out to day 16)

[TheStormExpert]

12z GFS back with development now in the NW Caribbean in about 10 days and quickly ejects it to the NE across Cuba and through the Central & SE Bahamas missing Florida to the Southeast. Just like with Nate it shows multiple vortices spinning around one big gyre keeping it from amounting to much.

[toad strangler]

12z GFS back with development now in the NW Caribbean in about 10 days and quickly ejects it to the NE across Cuba and through the Central & SE Bahamas missing Florida to the Southeast. Just like with Nate it shows multiple vortices spinning around one big gyre keeping it from amounting to much.

It's still something to watch and not to trust in this anomalous year. GFS really never lost it but rather switched to the EPAC for a spell. Signal has been there all along.

[gatorcane]

Development on the 06z GFS was further east. If that front is not as strong, it may not get pushed east over Cuba and Bahamas. The CMC also shows development in the NW Caribbean with the area moving NE SE of Florida but out in long-range.

[TheStormExpert]

12z GFS back with development now in the NW Caribbean in about 10 days and quickly ejects it to the NE across Cuba and through the Central & SE Bahamas missing Florida to the Southeast. Just like with Nate it shows multiple vortices spinning around one big gyre keeping it from amounting to much.

It's still something to watch and not to trust in this anomalous year. GFS really never lost it but rather switched to the EPAC for a spell. Signal has been there all along.

Yeah it's been back and forth with E-Pac or Western Caribbean for MANY runs now. Favoring the Western Caribbean, East Pacific is pretty much dead thanks to the developing La Niña.

[gatorcane]

GFS ensembles showing more enthusiasm:

[WeatherEmperor]

The 12z Euro shows vorticity perhaps starting in the SW Caribbean at 240hrs. I think we need to give it until tomorrow so the time can get into the Euro’s range but this could get interesting




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[Shell Mound]

According to the ECMWF and GFS forecast means, the MJO should be entering into a higher-amplitude, stronger signal and begin progressing eastward over the tropical Pacific through 24 October. Based on what I see and think, +VVP anomalies should approach or enter the western Caribbean by the last week of October. The leading edge of the amplification could induce lower-level strengthening of westerly (U- or horizontal) wind-vector components, which, combined with geographical features, could induce vorticity or "spin" over the southern Caribbean as early as 24 October. A similar situation occurred with Nate, aided by the effects of Pacific moisture, building subtropical ridging (convergent southeasterly flow), and nearby South-American terrain, except that in this case the monsoonal gyration may be weaker. This could actually help a system develop faster, as it would have less interaction with the monsoonal gyration, and hence fewer alternative "centers" to contend with. In this case, once it forms, a system may be able to consolidate faster than, say, Nate did, so long as shear remains low at the time of genesis. The monsoon will still be there, but the system may actually form just before the Pacific (MJO) really begins to influence things. If something develops, I suspect that conditions could well favor the seventh major hurricane of the season, but, as mentioned, I doubt that such a system would affect the mainland U.S., given its lateness in the season. The GFS's being suggestive of a track over the Antilles and east of Florida fits well with late-October and November climatology. The 1932 Cuba hurricane, Fox (1952), Michelle (2001), and Paloma (2008) took similar paths at this time of year. Also, given seasonal trends and climatology, anything that does manage to become a hurricane in the southwestern Caribbean could certainly become exceptionally intense. That area remains untouched, with heat content warmer than in 2005, and Nate did not attain hurricane status until it reached the southern Gulf of Mexico. The southwestern and western Caribbean Sea are in a pristine condition, with the warmest heat content in the basin. Another 1932-, Mitch-, Wilma- or Irma-type system is within the realm of possibility, should conditions remain favorable. I wouldn't even rule out a new record-breaker in terms of pressure and wind for the basin, a system that surpasses Irma, Wilma, Allen, or even the 1935 hurricane. I don't welcome such an outcome, but I think it needs to be kept in mind.

My gut feeling: before the 2017 season ends, we may see a system with a pressure below 880 mb and maximum sustained winds of 175 knots (200 mph) or greater. Gut-feeling odds: more probable than not. Gut-based result: Patricia (2015), but in the Atlantic rather than the eastern tropical Pacific.

Not trying to cause panic, and don't bet on it, but thinking aloud...

[gatorcane]

Happy hour GFS moves this NW into the NW Caribbean in the long-range then into Belize. That kind of positioning is no bueno for Florida in late October:

[toad strangler]

I think the GFS was chasing a ghost in the long range. It is almost Halloween after all...

[SFLcane]

Feel pretty confident season is about over for Florida GFS shows screaming westerlies in the GOM. Only a few patches of light winds across the basin. Now just some cool air!

[gatorcane]

The GFS OP still thinks we are in an El Niño. Has development on Pacific side again while CMC insists on Caribbean side. Seems Caribbean side is more likely because of La Niña. Just about coming into long-range Euro now so let’s see if it starts to pick up. This would be a last week in October event.

[Alyono]

GFS also has a tropical storm hitting Beaumont next Sunday

It truly is lost

[gatorcane]

GFS also has a tropical storm hitting Beaumont next Sunday

It truly is lost

Hmmm 12Z Euro is now showing something though. Odd for this time of year.

[Alyono]

we going to see a Juan? It would greatly reduce the chances of a Caribbean storm

[KatDaddy]

Hmmmmm.......another Juan perhaps? Many days to watch if anything develops.

[Steve]

we going to see a Juan? It would greatly reduce the chances of a Caribbean storm

Ghost of 85 rearing it’s head? That was one of the coolest storms we had here. About 2 2 1/2 Days of on again off again street flooding. Got chilly after it pulled out as it drug down a cold front that ushered in fall. That was the last bad system for the Bayou as it had coffins floating after popping out the ground. Lots of flooding down there. MJO is headed for hardcore phase 5. Coinciding with a burst in the WPAC would be a favorable area in the NW Gulf as Joe Bastardi showed on his Saturday summary. Idk if anything can get strong over there next weekend but it would be a fairly rare event for the back half of October.

[cajungal]

I don't remember Juan in 85 that much. I was only 9 years old. But flooding in the Houma area was extensive.

[LarryWx]

Between 10/26 and 10/28, 5 of the 12Z EPS' 50 members have a genesis of what becomes a TS+. Four of the 5 form in
the W Caribbean and one in the GOM. The one in the GOM then moves ENE and crosses W FL. Regarding the other 4, one crosses central Cuba and the NW Bahamas. One moves NNE crossing W Cuba, SW FL, and NC. One is crossing west central Cuba moving very slowly N. The last one is moving slowly NE well down in the W Caribbean.
So, 3 of the 50 members show a FL TS+ threat 10/28-31. Take that for what it is worth as the 0Z EPS had none of this and that is very late in the month. The latest H to hit FL in October on record since 1851 is 10/28 though the Yankee H and Kate of 1985 hit in Nov. I haven't compiled the TSs that have hit FL in late Oct yet.

**Correction made in bold**

[gatorcane]

MUCH more bullish on the 18Z GEFS and on the Caribbean side not the Pacific. I noticed the 18Z GFS OP shifted almost to the Caribbean this run instead of pacific. Only reason it doesn’t develop further is due to land interaction with Central America but its ensembles strongly favor the Caribbean as you would expect in La Niña:

[LarryWx]

MUCH more bullish on the 18Z GEFS and on the Caribbean side not the Pacific. I noticed the 18Z GFS OP shifted almost to the Caribbean this run instead of pacific. Only reason it doesn’t develop further is due to land interaction with Central America but its ensembles strongly favor the Caribbean as you would expect in La Niña:

Good post, Gator. If this weren't the Happy Hour GEFS, which has tended to be the most active GEFS in October in the W Caribbean, I'd say this is a pretty darn strong signal with it having at least half the members become a TS+ and 6 of 20 members become a H 10/27-31.

During the period 10/26-11/5, I found a respectable 8 hits on FL: one H and 7 TSs (including extratropical storms that had been TSs) on record that hit FL from geneses that were either in the W Caribbean or GOM since 1851 including Juan of 1985 and Mitch of 1998. So, far from impossible (once every 21 years on average). Hit dates: 10/26, 27, 28, 29, 31, 11/1, 3, 5. After 11/5, TC hits on FL from the Gulf/Caribbean have been fewer and further between.

Edit: Even the normally less active (vs 18Z GEFS) 0Z GEFS has 7 of 20 members having a TS+ from either a W Caribbean or GOM genesis (between 10/24 and 10/29) with 4 of those becoming a H. So, perhaps that will be a period to monitor though still far from a likelihood at this stage.