ATL: FIONA - Post-Tropical - Discussion

[LarryWx]

12z Best Track latitude is lower than first update.

Location: 9.2°N 23.7°W
Maximum Winds: 20 kt Gusts: N/A
Minimum Central Pressure: 1009 mb
Environmental Pressure: 1010 mb
Radius of Circulation: 120 NM
Radius of Maximum Wind: 80 NM

The fact that this is moving WSW in the eastern Atlantic is often a warning sign that it may not be an easy recurve/fish, especially when it isn't El Nino such as is the case this season. That combined with August geneses having about as high a chance as any time of the season of making it far across the ocean (clearly higher than Sep geneses) is a reason to not assume fish just yet.

[RL3AO]

Models have a bad habit of bringing these things north way too quickly. I wouldn't be surprised if this is still south of 20N in 7 days.

[Yellow Evan]

Until globals show otherwise, I'd still assume a recurve as the most likely option (but further west than the GFS/ECMWF have it).

[Nimbus]

It decided to stay down with the moisture in the ITCZ like the last wave.
Last wave did'nt try to climb out and close off till it got west of -53 and by then the shear just destroyed it.
Ridging could evolve differently than forecast I suppose.

[cycloneye]

Up to 40%-50%

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT MON AUG 15 2016

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Disorganized cloudiness and thunderstorms over the far eastern
Atlantic are associated with a tropical wave located a few hundred
miles south-southwest of the Cabo Verde Islands. Environmental
conditions are conducive for gradual development of this disturbance
during the next few days, but could become less favorable later this
week. The system is expected to move west-northwestward to
northwestward at 10 to 15 mph into the central tropical Atlantic
during the next several days.
* Formation chance through 48 hours...medium...40 percent
* Formation chance through 5 days...medium...50 percent

Forecaster Kimberlain

[Yellow Evan]

50% in 5 days sounds way too low. I'd prefer 40/80 at this point.

[gatorcane]

12z Best Track latitude is lower than first update.

Location: 9.2°N 23.7°W
Maximum Winds: 20 kt Gusts: N/A
Minimum Central Pressure: 1009 mb
Environmental Pressure: 1010 mb
Radius of Circulation: 120 NM
Radius of Maximum Wind: 80 NM

The fact that this is moving WSW in the eastern Atlantic is often a warning sign that it may not be an easy recurve/fish, especially when it isn't El Nino such as is the case this season. That combined with August geneses having about as high a chance as any time of the season of making it far across the ocean (clearly higher than Sep geneses) is a reason to not assume fish just yet.

Latest 12Z Euro running now now shows some WSW movement for the next 24 hours before it begins to turn more NW

[LarryWx]

Up to 40%-50%

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT MON AUG 15 2016

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Disorganized cloudiness and thunderstorms over the far eastern
Atlantic are associated with a tropical wave located a few hundred
miles south-southwest of the Cabo Verde Islands. Environmental
conditions are conducive for gradual development of this disturbance
during the next few days, but could become less favorable later this
week. The system is expected to move west-northwestward to
northwestward at 10 to 15 mph into the central tropical Atlantic
during the next several days.
* Formation chance through 48 hours...medium...40 percent
* Formation chance through 5 days...medium...50 percent

Forecaster Kimberlain

Note that this TWO expects it to move WNW to NW but it is not doing that yet and it has actually been moving WSW today.

[gatorcane]

12Z ECMWF going with development again. Run is out through 72 hours so far.

[Caneman12]

I believe the CMC is trash so is the GFS only look at the Euro only reliable model for now

[tolakram]

12Z Euro taking this directly NW for now. Interesting track since it shows little development yet sends it north. All steering levels indicate what should be west movement, not sure what the euro is seeing.

Steering: http://tropic.ssec.wisc.edu/real-time/d ... oom=&time=

[LarryWx]

12Z Euro taking this directly NW for now. Interesting track since it shows little development yet sends it north. All steering levels indicate what should be west movement, not sure what the euro is seeing.

Steering: http://tropic.ssec.wisc.edu/real-time/d ... oom=&time=

Also, the 12z Euro has the weak low intialized about 2.5-3 degrees too far north (near 12N vs the actual near 9-9.5 N) though it does have it move WSW for the 1st 24 hours before that NW turn.

[NDG]

12z Euro shows less of a weakness over the Atlantic on this run.

[cycloneye]

Moving 270 west.18z Best Track.

Location: 9.2°N 25.8°W
Maximum Winds: 25 kt Gusts: N/A
Minimum Central Pressure: 1008 mb
Environmental Pressure: 1011 mb
Radius of Circulation: 150 NM
Radius of Maximum Wind: 80 NM

Since the first run for 98L.

AL, 98, 2016081500, , BEST, 0, 92N, 205W, 20, 1009, DB, 0, , 0, 0, 0, 0, 1010, 120, 60, 0, 0, L, 0, , 0, 0, INVEST, S, 0, , 0, 0, 0, 0, genesis-num, 013, SPAWNINVEST, al752016 to al982016,
AL, 98, 2016081506, , BEST, 0, 92N, 221W, 20, 1009, DB, 0, , 0, 0, 0, 0, 1010, 120, 60, 0, 0, , 0, , 0, 0, INVEST, , 0, , 0, 0, 0, 0, genesis-num, 013,
AL, 98, 2016081512, , BEST, 0, 92N, 237W, 20, 1009, DB, 0, , 0, 0, 0, 0, 1010, 120, 80, 0, 0, L, 0, , 0, 0, INVEST, S, 0, , 0, 0, 0, 0, genesis-num, 013,
AL, 98, 2016081518, , BEST, 0, 92N, 258W, 25, 1008, DB, 34, NEQ, 0, 0, 0, 0, 1011, 150, 80, 0, 0, L, 0, , 0, 0, INVEST

[gatorcane]

12Z JMA is a little east of the northern Lesser Antilles at 168 hours with the system heading west.

[wxman57]

I don't see any south-of-west (not WSW) motion indicated by the EC or GFS. In fact, both indicate a course change to WNW very soon. Nothing to indicate this system, should it develop, will be any threat to land.

[gatorcane]

Wxman57, from TropicalTidibts site, we see WSW movement between hours 0 and 24 as shown below. Nonethless, I don't see any threat to land at the moment either given the weak subtropical ridge the models are showing:

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.

[abajan]

Up to 40%-50%

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT MON AUG 15 2016

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Disorganized cloudiness and thunderstorms over the far eastern
Atlantic are associated with a tropical wave located a few hundred
miles south-southwest of the Cabo Verde Islands. Environmental
conditions are conducive for gradual development of this disturbance
during the next few days, but could become less favorable later this
week. The system is expected to move west-northwestward to
northwestward at 10 to 15 mph into the central tropical Atlantic
during the next several days.
* Formation chance through 48 hours...medium...40 percent
* Formation chance through 5 days...medium...50 percent

Forecaster Kimberlain

Note that this TWO expects it to move WNW to NW but it is not doing that yet and it has actually been moving WSW today.

From the best of my recollection, it's actually pretty common for these systems to move in a somewhat south of west direction while in the far eastern Atlantic. That motion has little, if any, bearing on the eventual track.

[cycloneye]

 https://twitter.com/wxtrackercody/status/765270433084104704

[gatorcane]

12Z UKMET track: