GaWx

Per NHC, Fiona dropped another 0.2 of latitude between the 5PM (AST) and 8PM positions, which is south of the NHC track. It is now down to 16.1N vs 16.6N at the 11AM position during a period in which it was forecasted to be at 16.6N now. So, it is now 35 miles south of where the 11AM track had it for now.

Headed for NC?

Happy Hour GFS is way west vs 12Z!

12Z EPS implies ~30% risk of a CONUS TS+ landfall based on ~15 of TS+ members landfalling there. Per NHC, Fiona lost 0.3 degrees of latitude the last 6 hours.

I think that is more likely a cat 1 H landfall at WPB on the 12Z Euro (near 990 mb). Look for the 12Z EPS mean to shift SW.

It appears per satellite loops that there is a circulation at 11N, 23W, moving west. Anyone else see this?

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC AND ATLANTIC GLOBAL MODEL DATA TIME 1200UTC 15.09.2022 TROPICAL STORM FIONA ANALYSED POSITION : 16.3N 53.7W ATCF IDENTIFIER : AL072022 LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 15.09.2022 0 16.3N 53.7W 1008 39 0000UTC 16.09.2022 12 16.5N 56.3W 1007 40 1200UTC 16.09.2022 24 16.7N 58.9W 1007 37 0000UTC 17.09.2022 36 17.0N 61.4W 1006 32 1200UTC 17.09.2022 48 17.4N 63.5W 1006 34 0000UTC 18.09.2022 60 18.1N 65.4W 1005 36 1200UTC 18.09.2022 72 17.8N 67.5W 1004 43 0000UTC 19.09.2022 84 19.2N 68.9W 1001 43 1200UTC 19.09.2022 96 19.9N 69.8W 997 56 0000UTC 20.09.2022 108 20.7N 71.2W 994 54 1200UTC 20.09.2022 120 21.3N 72.0W 996 51 0000UTC 21.09.2022 132 22.0N 72.2W 993 47 1200UTC 21.09.2022 144 23.1N 72.2W 990 48

11 AM NHC kept it at 16.6N (straight west since last advisory).

Per satellite loops, it at least appears to be moving ever so slightly south of due west vs the 5AM NHC's ever so slight north of due west. It may very well be as far south as 16.5 or 16.4 N now though sometimes the satellite suggested location doesn't match the actual due to tilt. If it is at 16.4-5 N, that would be slightly south (by ~15 miles) of the 5 AM track's implied position of 16.6-7 N now. If that's true (although 15 miles may not seem like much), that would imply a slight southward track adjustment at 11AM. Other opinions on a likely 11 AM track adjustment?

This shows a slight SW trend of the mean track from 0Z to 6Z EPS. I think there will be more SW adjustments eventually though not necessarily consistently from run to run.

The 6Z EPS has 75% of members at or south of the south coast of the Dominican Republic. Odds of a move into the Gulf are increasing imo (assuming it survives).

TROPICAL DEPRESSION FIONA ANALYSED POSITION : 16.4N 51.4W ATCF IDENTIFIER : AL072022 LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 15.09.2022 0 16.4N 51.4W 1010 36 1200UTC 15.09.2022 12 16.4N 53.9W 1009 38 0000UTC 16.09.2022 24 16.7N 56.2W 1008 37 1200UTC 16.09.2022 36 17.0N 58.9W 1009 35 0000UTC 17.09.2022 48 17.5N 61.6W 1008 30 1200UTC 17.09.2022 60 17.8N 64.0W 1007 31 0000UTC 18.09.2022 72 18.0N 66.5W 1006 32 1200UTC 18.09.2022 84 18.6N 67.8W 1004 39 0000UTC 19.09.2022 96 18.8N 68.6W 1002 43 1200UTC 19.09.2022 108 19.8N 69.9W 996 53 0000UTC 20.09.2022 120 20.5N 71.2W 995 53 1200UTC 20.09.2022 132 21.1N 72.0W 996 51 0000UTC 21.09.2022 144 22.0N 72.2W 997 45

Followup: - The 12Z ICON makes this a H near 14N, 50W, and then takes it NW. - The 12Z JMA takes this westward to just E of LAs as a very weak low moving WNW at 192 hours. - The 12Z Euro is the 4th in a row that has a persistent surface low from the AEW just now leaving Africa. The prior three all hit the Lesser Antilles. This run has it just E of the LAs as of 168 moving W (Sept 21st) after which it moves W well into the Caribbean as a very weak low: Update for 12Z EPS: Those members at 240 which are located from NE of PR to the LAs to the MHs NE of the Leewards as well as those members S of PR and Hisp. in the Caribbean are from this AEW that's now just off Africa rather than from 96L. Some of those Caribbean members then go into the Gulf. Update: The 12Z UKMET has this: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 138 HOURS FORECAST POSITION AT T+138 : 12.9N 48.2W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 20.09.2022 144 13.2N 49.2W 1009 30

12Z UKMET TROPICAL DEPRESSION 96L ANALYSED POSITION : 16.5N 49.5W ATCF IDENTIFIER : AL962022 LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 14.09.2022 0 16.5N 49.5W 1010 36 0000UTC 15.09.2022 12 16.5N 52.2W 1010 34 1200UTC 15.09.2022 24 16.3N 54.8W 1010 36 0000UTC 16.09.2022 36 16.7N 56.0W 1009 39 1200UTC 16.09.2022 48 16.7N 59.0W 1009 36 0000UTC 17.09.2022 60 17.5N 61.6W 1008 32 1200UTC 17.09.2022 72 17.8N 63.7W 1007 31 0000UTC 18.09.2022 84 18.4N 65.5W 1006 32 1200UTC 18.09.2022 96 18.5N 67.7W 1005 35 0000UTC 19.09.2022 108 19.4N 68.7W 1002 40 1200UTC 19.09.2022 120 20.6N 70.1W 999 52 0000UTC 20.09.2022 132 21.2N 71.5W 997 53 1200UTC 20.09.2022 144 22.0N 72.6W 998 48

While we're concentrating on Invest 96L for good reason, folks should probably at least keep one eye on an AEW that's coming off Africa in ~12 hours. It has been quite active over W Africa. Several models (Euro, ICON, CMC) are now taking this at least to 50W in the MDR. The last 3 Euro runs haven taken it to at least the Lesser Antilles. The latest Euro takes this to just SW of PR as a TS moving WNW at 240 hours (9/24).

Convectively, the IR satellite looks more impressive than either GFS or CMC IR simulation maps look. Also, it looks more impressive than 24 hours ago, which itself looked rather impressive, itself. Shear is pretty low and SSTs are warming as it moves westward. This is moving over a climo favored region for development in mid Sept in a non-El Nino season. Several third year cold ENSO analogs have had genesis within 51-57W between 9/13 and 9/20. Thus, I remain confident this will become a TC and it will probably become a TD before 60W. It doesn't matter much to me how the season has gone so far. That being said, the UKMET (0Z) once again does nothing with it: TROPICAL DEPRESSION 96L ANALYSED POSITION : 15.7N 47.3W ATCF IDENTIFIER : AL962022 LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 14.09.2022 0 15.7N 47.3W 1011 24 1200UTC 14.09.2022 12 CEASED TRACKING

12z Euro looks to be taking a little bit further SW track based on 96 hours, when the very weak low center is 200 miles south of PR. Edit: At 192, it is in the W Caribbean with a strong high to its north. Upon further review, the 12Z Euro seems to be combining 96L with some energy coming from the SW Caribbean. Anyone notice this? So, I'll need to later look at the 6 hour maps to see exactly where 96L tracked. And upon even more review: Check out the 12z Euro 850 mb vorticity maps. If you look closely, the NE portion of the 240 hour Bahamas low actually is associated with vorticity that is still over Africa, not the low now just offshore Africa, and won't come off til hour 48! I mean this vorticity speeds like a racehorse across the MDR! This is pretty fascinating.

TWO remains 30%/40% but the wording seems slightly less bullish: Tropical Weather Outlook NWS National Hurricane Center Miami FL 200 PM EDT Tue Sep 13 2022 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: 1. Central Tropical Atlantic: Showers and thunderstorms associated with a tropical wave located about 1000 miles east of the Lesser Antilles have changed little in organization since this morning. Although environmental conditions are only marginally conducive, some gradual development of this system is possible over the next few days. A tropical depression could form while the system moves westward to west-northwestward over the tropical Atlantic and approaches the Leeward Islands on Friday. * Formation chance through 48 hours...low...30 percent. * Formation chance through 5 days...medium...40 percent.

The 12Z ICON is a bit further south and a little weaker with it initially getting to just S of PR at 120 hours before later curving NW and then N while strengthening into a H. It ends up just E of the SE Bahamas, which is the furthest W of any run. Is this a sign that there this will keep trending SWard on later runs? I wouldn't be surprised if this ends up in the Gulf based partially on analogs fwiw. The 12Z GFS does ~nothing with this through 204. Its vorticity gets into the W Caribbean and may be a hint to consider. For the 2nd run in a row, the 12Z CMC has this as a TC in the Gulf with this run having it as a TS in the far E Gulf at 192. It then turns west and ends up as a H in the W GOM aiming for TX. The 12Z JMA, which had this as a TC the prior two days, is slightly weaker through 72 (1012 mb vs 1011 mb near the LAs). The rest of the run won't be for awhile. The 12Z UKMET, which has it initially only because that's how this model handles all Invests, drops this immediately afterward: TROPICAL DEPRESSION 96L ANALYSED POSITION : 15.3N 46.0W ATCF IDENTIFIER : AL962022 LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 13.09.2022 0 15.3N 46.0W 1011 25 0000UTC 14.09.2022 12 CEASED TRACKING

Thanks. Something to keep in mind. For those who haven't seen it, there's a new thread for this now that it has been designated as Invest 96L:

Invest 96L was just designated. Other than the precursor to Earl, this AEW to the best of my memory has had the most convection this far west in the MDR (40-45W) since the precursor to Bonnie way back in late June. The first model run with this as a TC was the UKMET way back at 12Z on September 4th though that had tropical genesis way too early (Sept 9th near 26W). Since then, just about every operational model has had this on some runs though it is still on and off. For example, the 6Z Euro dropped it as a TC after having it on the prior two runs. A good number of EPS and GEFS members have shown this as a hurricane threatening the CONUS Sept 22-26, including quite a few of them landfalling in the SE, some in the Gulf, and even a few runs in the NE US including one on NYC. There are eight third year cold ENSO analog seasons I've been following. Among those, three of them had either the biggest or near the biggest impact of the entire season (strongest impact overall Gulf coast of FL) become a TC between 51W and 57W and during the period 9/13 and 9/20 fwiw. TWO odds have just increased to make this a 5 day orange from the previous lemon: ZCZC MIATWOAT ALL TTAA00 KNHC DDHHMM Tropical Weather Outlook NWS National Hurricane Center Miami FL 800 AM EDT Tue Sep 13 2022 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: 1. Central Tropical Atlantic: Conventional and Low-earth orbit satellite data indicate that showers and thunderstorms associated with a tropical wave located about midway between the west coast of Africa and the Windward Islands have increased and become better organized since yesterday afternoon. Further development of this system is possible and a tropical depression could form over the next several days while it generally moves westward to west-northwestward over the central tropical Atlantic and approaches the Leeward Islands on Friday. * Formation chance through 48 hours...low...30 percent. * Formation chance through 5 days...medium...40 percent.

I recall past large moist AEWs embedded in lots of surrounding dry air seeming to do well. It is almost as if there is a moat protecting the moisture from the nearby dryness. We're still 5-6 hours from DMAX, too. Edit: The 0Z UKMET dropped it again just as it did on yesterday's run. I'm talking about the textual output. However, the map does show a weak surface low over the Leewards at 72 hours fwiw.

Yeah, I just saw that the 18Z Euro now has TCG. No recent Euro run had had this. That means just about all of the latest operational runs are developing this. Looking at the very impressive convection and the strong model support, and when considering analogs as well as near peak season climo in mid September, I'd now be quite surprised if this doesn't become a TC. Just looking at it, it is screaming genesis. It doesn't at all resemble the many dry AEWs of recent weeks. Who's to say that this won't be the most impactful storm of the season? Keep in mind that should this end up a big deal that the UKMET of 8 days ago was the first model to show TCG for this.

Other than the precursor to Earl, I can't recall any other AEW with nearly this much convection since the precursor to Bonnie in late June. I think it is going to eventually lead to a TC though it may take many days to do so.

Mike, I just look at the individual members on Tropical Tidbits and see where they go.