EPAC: ADRIAN - Post-Tropical

[cycloneye]

Tropical Storm Adrian Discussion Number 3
NWS National Hurricane Center Miami FL EP012017
400 AM CDT Wed May 10 2017

Although the central convection has weakened during the past few
hours, the overall cloud pattern has changed very little in
organization. Satellite intensity estimates from both TAFB and SAB
remain at T2.5 on the Dvorak scale. However, an ASCAT pass around
0400 UTC showed a few vectors of 40 kt, and this is the intensity
assigned to Adrian.

It is interesting to note that the GFS is basically the only
dynamical model that significantly intensifies Adrian. Both the HWRF
and the ECMWF do not. In fact, the latest ECMWF weakens the cyclone
to a broad area of low pressure within the next 5 days. Based on
continuity, the fact that Adrian is moving over warm waters and
the shear is low, gradual strengthening is still forecast. The NHC
intensity forecast, however, is a little lower than indicated in the
previous one.

The best estimate of the initial motion is toward the northwest or
310 degrees at 6 kt. Adrian is expected to be steered on this
general track by a ridge of high pressure over Mexico and Central
America. However, these currents are forecast to collapse in about
2 days leaving Adrian embedded within a very week steering flow.
The cyclone most likely will begin to meander well south of Mexico
in 3 days.


FORECAST POSITIONS AND MAX WINDS

INIT 10/0900Z 10.0N 92.7W 40 KT 45 MPH
12H 10/1800Z 10.6N 93.5W 40 KT 45 MPH
24H 11/0600Z 11.1N 94.1W 50 KT 60 MPH
36H 11/1800Z 11.5N 95.0W 55 KT 65 MPH
48H 12/0600Z 12.0N 96.0W 60 KT 70 MPH
72H 13/0600Z 12.5N 97.0W 70 KT 80 MPH
96H 14/0600Z 13.0N 97.0W 75 KT 85 MPH
120H 15/0600Z 13.5N 96.5W 75 KT 85 MPH

$$
Forecaster Avila

[cycloneye]

This tells all about the models.
 https://twitter.com/EricBlake12/status/862263412738453504

[tolakram]

GFS Parallel is now the only model that develops this quickly, if at all. Will the updated model prove to be most accurate?

[cycloneye]

Wow.06z GFS now goes out to sea to almost 120W at day 16.

[NDG]

Adrian does not look too good this morning,most of the convection is on its NW quadrant near the MLC, runs of HWRF and last few runs of Euro might have been right after all of Adrian struggling through at least the next 72 hours.

[1900hurricane]

Looks like Adrian is dealing with a little bit of backshear this morning. Derived shear maps don't indicate much shear, but cloud motions on visible imagery show the CDO anvils having trouble expanding behind the storm.

[cycloneye]

Tropical Storm Adrian Discussion Number 4
NWS National Hurricane Center Miami FL EP012017
1000 AM CDT Wed May 10 2017

Adrian's satellite presentation is less organized than yesterday,
with little evidence of convective banding features along with a
few bursts of deep convection to the north and northwest of the
estimated center. Vertical cross-sections through the latest GFS
model analysis indicate a significant tilt of the vortex from
southeast to northwest with height. This is consistent with
analyses from UW-CIMSS that show around 20-25 kt of mid-level
southeasterly shear across the tropical cyclone. This disruption
of the vertical coherency of the system is likely one of the reasons
that Adrian has not strengthened much. The current intensity is
held at 40 kt based on earlier scatterometer data, although the
latest Dvorak estimates and the disorganized cloud pattern suggest
it might be a little weaker. The global models do not call for
Adrian to intensify over the next several days, but the
statistical/dynamical models still show the system becoming a
hurricane within 72 hours. The official intensity forecast is a
little lower than the previous one and close to the latest SHIPS
prediction, and is of low confidence.

Even with high-resolution visible imagery, the center is difficult
to locate. Based mainly on microwave and scatterometer fixes, the
initial motion estimate is a rather uncertain 315/6 kt. A mid-level
ridge to the north of Adrian should induce a northwestward to
west-northwestward motion for the next several days. Later in the
forecast period, the ridge is predicted to collapse, leaving the
tropical cyclone in a region of very weak steering currents.
Based on this expected evolution of the large-scale flow, the
official track forecast shows no motion by days 4 and 5.

FORECAST POSITIONS AND MAX WINDS

INIT 10/1500Z 10.4N 92.7W 40 KT 45 MPH
12H 11/0000Z 10.8N 93.2W 40 KT 45 MPH
24H 11/1200Z 11.4N 94.1W 45 KT 50 MPH
36H 12/0000Z 11.9N 95.1W 50 KT 60 MPH
48H 12/1200Z 12.2N 96.0W 55 KT 65 MPH
72H 13/1200Z 12.7N 97.0W 65 KT 75 MPH
96H 14/1200Z 13.0N 97.0W 70 KT 80 MPH
120H 15/1200Z 13.0N 97.0W 70 KT 80 MPH

$$
Forecaster Pasch

[Kazmit]

Models seem to take it meandering south of Mexico in a a few days. Still quite a bit of uncertainty.

[TheStormExpert]

12z GFS dissipates Adrian within the next 36-48 hours.

[galaxy401]

Pardon me for being late here but this is now the second straight year both basins spawn a storm before the official start of the season. It's quite crazy that no storm has formed in the Pacific a week before the start even though it seems to happen in the Atlantic every couple years.

Yeah Adrian is getting complicated for forecasters. Looks like the preseason conditions are back.

[TheStormExpert]

Something you don't see too often in the Eastern Pacific.

 https://twitter.com/tropicaltidbits/status/862362945690447872

[dexterlabio]

If this dissipates for good then there will be nothing to cross over to the Atlantic, then? So much for the Barbara/Andrea repeat, though still a plus for the earliest EPAC TS on record..

[dexterlabio]

What's with the oh-so inconsistent global models, by the way? Does it have something to do with the MJO? I hope the models will perform better when the heart of the NHem cyclone season comes.

[gatorcane]

12Z ECMWF doesn't develop it. Amazing how both GFS and ECMWF were so bullish at times showing CAT 5 solutions (ECMWF) and now basically we may not get more than a TS. Even the best models in the world can be fooled!

[cycloneye]

Amazing that 12z ECMWF develops it on days 9-10.

[NDG]

The only model that did not fooled us was the HWRF.
Adrian got decoupled faster than what I have ever seen before in the EPAC.

[gatorcane]

The only model that did not fooled us was the HWRF.
Adrian got decoupled faster than what I have ever seen before in the EPAC.

This is very typical of an Atlantic TC - models show development in long to medium range, area of convection looks good and appears to be quickly organizing then it gets ripped apart by shear with nothing but a naked swirl. Now to see this in the EPAC is not something that happens often as Levi points out...looks like the naked swirl is around 10.5N 92.5W.

[cycloneye]

No more forecast to be a Hurricane.What a change.


Tropical Storm Adrian Discussion Number 5
NWS National Hurricane Center Miami FL EP012017
400 PM CDT Wed May 10 2017

Adrian is not a well-organized tropical cyclone, and it continues
to lack vertical coherence. Analyses from the GFS and ECMWF global
models continue to show a pronounced southeast to northwest tilt
with height, likely due to significant mid-level southeasterly
shear. Visible satellite images show an unimpressive low-cloud
swirl centered well to the southeast of a ragged area of deep
convection, which is apparently Adrian's center of circulation. The
intensity is reduced to 35 kt based on Dvorak classifications from
TAFB and SAB. The GFS and ECMWF models do not intensify the system,
and in fact practically dissipate it in a few days. HWRF shows only
slight strengthening over the forecast period, and has been
increasingly less aggressive over the past few runs. The SHIPS
model continues to insist that Adrian will eventually become a
hurricane. Based on the current state of the tropical cyclone and
the dynamical guidance, the official intensity forecast has been
significantly reduced in comparison to the previous ones. This is
close to the latest intensity model consensus, IVCN. Alternatively,
if Adrian does not make a comeback soon, the system could dissipate.

After relocating the past couple of working best track center
positions southeastward to account for the current position
estimate, the initial motion estimate is about 315/4 kt. Adrian is
expected to turn toward the west-northwest, on the south side of a
mid-level ridge, over the next couple of days. Thereafter the ridge
is forecast to collapse, leaving the tropical cyclone embedded in
weak steering currents. The official track forecast, like the
previous one, shows the system slowing to a halt later in the
forecast period.

FORECAST POSITIONS AND MAX WINDS

INIT 10/2100Z 10.5N 92.7W 35 KT 40 MPH
12H 11/0600Z 11.2N 93.6W 35 KT 40 MPH
24H 11/1800Z 11.8N 94.8W 35 KT 40 MPH
36H 12/0600Z 12.2N 95.7W 40 KT 45 MPH
48H 12/1800Z 12.5N 96.6W 40 KT 45 MPH
72H 13/1800Z 12.8N 97.0W 50 KT 60 MPH
96H 14/1800Z 13.0N 97.0W 50 KT 60 MPH
120H 15/1800Z 13.0N 97.0W 55 KT 65 MPH

$$
Forecaster Pasch

[Kingarabian]

Guess what? GFS back on the hurricane train in its 18z run.

[NDG]

Guess what? GFS back on the hurricane train in its 18z run.

Best thing to do is stick with HWRF for now.