ATL: GERT - Remnants - Discussion

[zhukm29]

Talk about a storm that is defying the models and just won't die! TD6 has lived long enough to finally get an ASCAT pass, which could actually support TS intensity if you consider that ASCAT typically undersamples storms like these (and certainly makes it more likely that TD6 was a TS yesterday). If you included the flagged barbs (not yet on FNMOC), then the max wind is above TS level at ~35+kt.

[Landy]

We have Gert!!!
 https://twitter.com/NHC_Atlantic/status/1693477036701241777

[AnnularCane]

Wow... Imagine what she could do without all that shear bugging her.

Triplet storms.

[Subtrop]

Tropical Storm Gert Special Discussion Number 7
NWS National Hurricane Center Miami FL AL062023
1200 AM AST Mon Aug 21 2023

Recent satellite wind-derived data indicated that winds in the
northeast quadrant were a little over 35 kt. Conventional enhanced
infrared imagery showed cooling cloud tops of -85 Celsius in the
same region of the cyclone. Accordingly, the depression is
upgraded to a tropical storm on this Special Advisory.

No changes to the forecast track and intensity philosophy are
required. Since the environment is still expected to be
hostile with very strong westerly shear during the next day or so,
Gert should degenerate into a remnant low later today, and
dissipate by Tuesday.


FORECAST POSITIONS AND MAX WINDS

INIT 21/0400Z 16.7N 55.9W 35 KT 40 MPH
12H 21/1200Z 16.8N 57.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 22/0000Z...DISSIPATED

$$
Forecaster Roberts

[ElectricStorm]

Well hello Gert

Now 3 of the 5 AOIs have become NS and the other two are likely to follow shortly. Crazy

[LemieT]

Tropical Storm Gert Special Discussion Number 7
NWS National Hurricane Center Miami FL AL062023
1200 AM AST Mon Aug 21 2023

Recent satellite wind-derived data indicated that winds in the
northeast quadrant were a little over 35 kt. Conventional enhanced
infrared imagery showed cooling cloud tops of -85 Celsius in the
same region of the cyclone. Accordingly, the depression is
upgraded to a tropical storm on this Special Advisory.

No changes to the forecast track and intensity philosophy are
required. Since the environment is still expected to be
hostile with very strong westerly shear during the next day or so,
Gert should degenerate into a remnant low later today, and
dissipate by Tuesday.


FORECAST POSITIONS AND MAX WINDS

INIT 21/0400Z 16.7N 55.9W 35 KT 40 MPH
12H 21/1200Z 16.8N 57.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 22/0000Z...DISSIPATED

$$
Forecaster Roberts

I applaud the NHC for the upgrade even though could technically just have left it alone until 5, especially since at the 12H point it's forecast to be dead.

[dexterlabio]

Deserves a name for its resilience

[chaser1]

Gert - gonna be quite the ACE monster.

[Hammy]

This was quite a surprise when I checked the map, I had to look at it a couple times to make sure I was seeing it right. That's what, three storms named in 24 hours?

[HurricaneEnzo]

Worst looking set of triplets you will probably ever see in the Atlantic

[cycloneye]

Tropical Storm Gert Discussion Number 8
NWS National Hurricane Center Miami FL AL062023
500 AM AST Mon Aug 21 2023

After a brief intensification period overnight, Gert is quickly
unraveling this morning. The surface circulation is becoming
ill-defined while the associated sheared mass of convection is
shrinking. Although the cloud pattern has certainly become less
organized during the past few hours, the initial intensity is
generously held at 35 kt for this advisory and is supported by the
Dvorak satellite intensity estimates. Despite a rather diffluent
upper-wind pattern, strong, persistent westerly shear and a
statically stable and dry mid-tropospheric surrounding air mass
should force Gert's surface center to separate farther from the
diminishing convective mass later today and degenerate to a remnant
low by this evening. The morning's global model simulated infrared
imagery also shows the cyclone opening to a trough of low pressure
in less than 36 hours, and the NHC official forecast reflects this
prediction.

The initial motion is estimated to be westward, or 280/8 kt. A
gradual turn toward the west-northwest is expected by tonight, and
this general motion should continue until dissipation occurs on
Tuesday. The official forecast has been adjusted slightly to the
right of the previous one and is based on the simple and NOAA HFIP
Corrected Consensus forecasts.


FORECAST POSITIONS AND MAX WINDS

INIT 21/0900Z 16.7N 56.4W 35 KT 40 MPH
12H 21/1800Z 17.0N 57.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
24H 22/0600Z 17.6N 59.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
36H 22/1800Z...DISSIPATED

$$
Forecaster Roberts

[Iceresistance]

Worst looking set of triplets you will probably ever see in the Atlantic

A very unexpected set of triplets too, Emily is about to be a goner.

[Sciencerocks]

[cycloneye]

Tropical Storm Gert Discussion Number 9
NWS National Hurricane Center Miami FL AL062023
1100 AM AST Mon Aug 21 2023

Gert barely qualifies a tropical cyclone. Visible satellite imagery
indicates it still has a well-enough defined circulation sustained
by a small area of deep convection that is displaced east of Gert's
surface center. That said, during the few hours since sunrise, the
tropical storm's circulation appears to have become stretched as
convection has waned. The initial intensity estimate is 35 kt based
on recent satellite estimates and ASCAT data last night, but new
ASCAT data is expected very soon that will provide better
information about the current maximum winds.

Strong upper-level winds associated with an upper-level low to the
north of Gert and outflow from the more robust Franklin to its west
ought to prevent Gert's convection from getting better organized.
Most dynamical models continue to indicate that Gert will open into
a trough within the next 12-36 h. While the tiny tropical cyclone
has been quite persistent thus far, its hard to envision Gert
lasting much longer in its current environment. Although the NHC
forecast maintains Gert for a little longer, it could realistically
dissipate at any time.

The initial motion of the tropical cyclone remains westward at a
slightly slower forward pace than overnight. Gert (or its remnants)
will likely turn west-northwestward or northwestward by tonight
until dissipation occurs. The NHC track forecast is very close to
the various consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT 21/1500Z 16.9N 57.0W 35 KT 40 MPH
12H 22/0000Z 17.2N 58.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
24H 22/1200Z 17.8N 59.1W 30 KT 35 MPH...POST-TROP/REMNT LOW
36H 23/0000Z...POST-TROP/REMNT LOW

$$
Forecaster D. Zelinsky

[cycloneye]

Tropical Depression Gert Discussion Number 10
NWS National Hurricane Center Miami FL AL062023
500 PM AST Mon Aug 21 2023

Gert continues to be sustained by a very small but persistent area
of convection east of its surface wind center. ASCAT data that came
in 5 minutes after the release of the previous advisory showed peak
winds of just above 25 kt well to the north of Gert's center. South
of Gert is mostly light and variable winds. Assuming Gert has
weakened further a little since then, its intensity has been lowered
to 25 kt.

All models continue to suggest that Gert will struggle in the face
of strong upper-level winds and a very dry surrounding environment.
The small tropical depression will likely either lose organized deep
convection and become a remnant low or dissipate at almost any time.
There is a chance that Gert could persist as a remnant low beyond
the 24 h shown in the NHC forecast, but it is unlikely that Gert
will have sufficient organized deep convection to be classified as a
tropical cyclone in that case. Gert is moving west-northwestward,
but the depression or its remnants should turn more northwestward
by tomorrow. No noteworthy changes were made to the NHC track or
intensity forecasts with this advisory.


FORECAST POSITIONS AND MAX WINDS

INIT 21/2100Z 17.1N 57.5W 25 KT 30 MPH
12H 22/0600Z 17.6N 58.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 22/1800Z 18.5N 59.6W 20 KT 25 MPH...POST-TROP/REMNT LOW
36H 23/0600Z...DISSIPATED

$$
Forecaster D. Zelinsky

[Sciencerocks]

[Sciencerocks]

[cycloneye]

Tropical Depression Gert Discussion Number 11
NWS National Hurricane Center Miami FL AL062023
1100 PM AST Mon Aug 21 2023

Gert appears to be on its last legs tonight. While some convection
remains near the small cyclone, the surface circulation is becoming
less well defined, and the system could be opening up into a
trough. I don't have enough confidence to issue the last advisory
based on the satellite data alone, so for continuity Gert will
remain a 25-kt tropical depression.

Strong shear should weaken the system while it moves west-
northwestward, and Gert is forecast to open up into a trough of low
pressure on Tuesday. No signficant changes were made to the NHC
track or intensity forecasts, which was also consistent with the
latest consensus aids and global model predictions.


FORECAST POSITIONS AND MAX WINDS

INIT 22/0300Z 17.1N 58.4W 25 KT 30 MPH
12H 22/1200Z 17.5N 59.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
24H 23/0000Z...DISSIPATED

$$
Forecaster Blake

[ScottNAtlanta]

I think it is funny that every advisory on this says it is going to dissipate any minute now...lol You go Gert...prove 'em wrong!

[wxman57]

It HAS dissipated, the NHC just won't stop CPR.