ATL: FIONA - Post-Tropical - Discussion

[Cainer]

Looking good.

Looks like there's even a 35kt barb on the western edge of the ASCAT scan. Definitely at least a tropical depression.

[Yellow Evan]

if this isn't a TD or TS, I don't know what is.

[weathaguyry]

if this isn't a TD or TS, I don't know what is.

I agree, I am sitting here refreshing the NHC website every 10 seconds looking for those big red letters at the top of the screen

[Socalhurcnegirl227]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT TUE AUG 16 2016

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

Showers and thunderstorms associated with a low pressure area
located about 650 miles west-southwest of the Cabo Verde Islands
have become more concentrated and better organized during the past
several hours. If this development trend continues, advisories
would be initiated on a tropical depression tonight or Wednesday.
This system is expected to move generally northwestward over the
open waters of the central Atlantic during the next several days.
* Formation chance through 48 hours...high...90 percent
* Formation chance through 5 days...high...90 percent

$$
Forecaster Brown

[ouragans]

Keep in mind there is no threat to land. There will be no rush to upgrade to TD6. And even if there is strong evidence of LLC, the NHC might choose to be conservative, waiting for the first visible imagery to upgrade, at 9z

[NDG]

And we have TD 6!

[weathaguyry]

And we have TD 6! I was getting so antsy!!!

[cycloneye]

BULLETIN
TROPICAL DEPRESSION SIX ADVISORY NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062016
1100 PM AST TUE AUG 16 2016

...TROPICAL DEPRESSION FORMS OVER THE EASTERN ATLANTIC...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...12.6N 34.1W
ABOUT 715 MI...1150 KM WSW OF THE CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES

TROPICAL DEPRESSION SIX DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062016
1100 PM AST TUE AUG 16 2016

Convective activity associated with the tropical wave and associated
low pressure area over the tropical Atlantic has become more
concentrated and better organized this evening, and a recent ASCAT
overpass indicates that the circulation has become better defined.
Based on these data, this system has been designated a tropical
depression, and advisories are being initiated at this time. The
initial wind speed of 30 kt is supported by the scatterometer data.
Some northeasterly shear is affecting the depression, with the
center located near the northeastern edge of the primary convective
mass. The shear is forecast to decrease tonight and remain low
during the next couple of days which favors strengthening. However,
dry mid-level air is lurking just to the north of the depression,
and intrusions of this unfavorable airmass could arrest development.
The NHC forecast shows gradual strengthening during the next couple
of days, but it is on the lower side of the guidance, closest to the
LGEM and intensity consensus. Later in the forecast period,
increasing southwesterly shear being produced by a mid- to
upper-level trough over the central Atlantic is likely to weaken the
tropical cyclone.

The initial motion estimate is a somewhat uncertain 310/12 kt. The
depression is forecast to move generally northwestward into a
weakness in the subtropical ridge over the central Atlantic. The
track guidance is in relatively good agreement through 48 hours, but
there is a large spread between the GFS-based guidance and the ECMWF
later in the period. The ECMWF and the majority of its ensemble
members depict a much weaker and shallower cyclone that turns
west-northwestward in the low-level flow after 48 hours. On the
other hand, the GFS, GFS ensemble mean, GFDL, and HWRF take a
stronger cyclone more poleward. For now, the NHC track is between
these two distinct solutions, and is located just south of the
multi-model consensus at days 4 and 5.


FORECAST POSITIONS AND MAX WINDS

INIT 17/0300Z 12.6N 34.1W 30 KT 35 MPH
12H 17/1200Z 13.7N 35.6W 35 KT 40 MPH
24H 18/0000Z 15.2N 37.2W 40 KT 45 MPH
36H 18/1200Z 16.8N 38.8W 45 KT 50 MPH
48H 19/0000Z 18.1N 40.2W 50 KT 60 MPH
72H 20/0000Z 20.0N 43.2W 50 KT 60 MPH
96H 21/0000Z 22.5N 46.5W 45 KT 50 MPH
120H 22/0000Z 25.0N 50.0W 40 KT 45 MPH

$$
Forecaster Brown

[cycloneye]

[Yellow Evan]

Keep in mind there is no threat to land. There will be no rush to upgrade to TD6. And even if there is strong evidence of LLC, the NHC might choose to be conservative, waiting for the first visible imagery to upgrade, at 9z

Doesn't matter anymore, but a tropical cyclone is a tropical cyclone no matter how close/far it is from land, so IMO there's no reason to be conservative.

[TheStormExpert]

Only forecasting a peak at 50kts in 48-72hrs.

FORECAST POSITIONS AND MAX WINDS

INIT 17/0300Z 12.6N 34.1W 30 KT 35 MPH
12H 17/1200Z 13.7N 35.6W 35 KT 40 MPH
24H 18/0000Z 15.2N 37.2W 40 KT 45 MPH
36H 18/1200Z 16.8N 38.8W 45 KT 50 MPH
48H 19/0000Z 18.1N 40.2W 50 KT 60 MPH
72H 20/0000Z 20.0N 43.2W 50 KT 60 MPH
96H 21/0000Z 22.5N 46.5W 45 KT 50 MPH
120H 22/0000Z 25.0N 50.0W 40 KT 45 MPH

[floridasun78]

ok it td6 as nhc say could be late today

[abajan]

Keep in mind there is no threat to land. There will be no rush to upgrade to TD6. And even if there is strong evidence of LLC, the NHC might choose to be conservative, waiting for the first visible imagery to upgrade, at 9z

Doesn't matter anymore, but a tropical cyclone is a tropical cyclone no matter how close/far it is from land, so IMO there's no reason to be conservative.

Agreed. To me it's just as ridiculous as debating if a tree really fell in the forest if no one was around to hear it fall.
EDIT: Hang on. I think I got that wrong. It's about if it made a sound when it fell. Whatever.

[Hammy]

In four days we went from nothing on the models, to 10% chance of development, to a depression on the verge of being named. Just shows how fast things can change this time of year.

[AxaltaRacing24]

In four days we went from nothing on the models, to 10% chance of development, to a depression on the verge of being named. Just shows how fast things can change this time of year.

Shh. The season is dead and activity is not allowed in two weeks as it is extremely unfavorable.

[Hurricaneman]

This could also just as easily recurve east of where the models have it too

The posts in this forum are NOT official forecast 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 National Hurricane Center and National Weather Service

[Aric Dunn]

There is still quite a bit of variability in the the models. as is always the case until it makes the turn you can rely on the models. as of right now according to the models it should be already moving NW it is not.

It is already welllll west of the forecast points ... the ridging maybe stronger . if it misses the weakness where it is.. it will likely become a west runner. which both the Euro and GFS showed yesterday morning..

[stormwise]

Unless there is a dramatic change in conditions, looking at the above plot a west runner will be a sheared storm.

[Aric Dunn]

Unless there is a dramatic change in conditions, looking at the above plot a west runner will be a sheared storm.

yeah a lot of possibilities. it also wont be sheared long then conducive then more shear.. hard to tell.

[HurricaneRyan]

If this ends up being Fiona, it might be similar to the 2010 storm.