EPAC: FLOSSIE - Remnants

[Ntxw]

Flossie is a bit too far north too early. It's too close to 15N being just about 125W.

[cycloneye]

000
WTPZ42 KNHC 311436
TCDEP2

Hurricane Flossie Discussion Number 13
NWS National Hurricane Center Miami FL EP072019
500 AM HST Wed Jul 31 2019

Flossie has the structure of a strongly sheared cyclone. Several
recent microwave passes have revealed that Flossie's center is
displaced to the northwest of all of its deep convection, and IR
imagery shows a sharp cloud-top temperature gradient in the
northwest quadrant of the hurricane. A blend of Final-T and CI
numbers from TAFB and SAB is the basis for the initial intensity of
65 kt, however it is certainly possible that Flossie is weaker than
that.

Given the current structure of Flossie (or lack thereof), a
substantial change was made to the intensity forecast. The global
models indicate that the current shear affecting the cyclone will
likely continue for another 24 h or so and Flossie is now forecast
to become a tropical storm during that time. In fact, the
statistical guidance suggests that Flossie will merely gradually
weaken for the next 5 days. On the other hand, the GFS, ECMWF, and
regional hurricane models indicate that the upper-level environment
could become more favorable in a few days, so some
re-intensification is possible at that time. The NHC forecast now
closely follows the intensity consensus through 48 h and then blends
back toward the previous forecast at 72 h and beyond, still favoring
the dynamical models at that time.

On the other hand, very little adjustment was required to the track
forecast. The initial motion is 285/13 kt, and a persistent
mid-level ridge to the north should keep Flossie moving
west-northwestward or westward at a steady forward speed for the
next 4 to 5 days. The track guidance remains very tightly clustered,
and the NHC forecast is very close the typically reliable TVCE and
HCCA aids.


FORECAST POSITIONS AND MAX WINDS

INIT 31/1500Z 14.0N 125.8W 65 KT 75 MPH
12H 01/0000Z 14.5N 127.7W 60 KT 70 MPH
24H 01/1200Z 15.2N 130.3W 60 KT 70 MPH
36H 02/0000Z 15.8N 133.0W 65 KT 75 MPH
48H 02/1200Z 16.2N 135.7W 65 KT 75 MPH
72H 03/1200Z 17.2N 141.3W 75 KT 85 MPH
96H 04/1200Z 17.8N 146.5W 75 KT 85 MPH
120H 05/1200Z 19.0N 151.5W 60 KT 70 MPH

$$
Forecaster Zelinsky

[Kingarabian]

Worrying that the NHC continues to say it'll likely re-strengthen.

[wxman57]

:uarrow: Worrying that the NHC continues to say it'll likely re-strengthen.

There's a good reason why in over 200 years, only a single hurricane has survived to strike the islands from the east, the 1871 hurricane. The atmosphere is just quite hostile east of the islands. Most hurricanes weaken to a weak TS or a depression when approaching from the east.

Oh, here's a zoomed-in visible image of Flossie this morning. Crosshairs mark the center. No way in the world this is a hurricane.

[wxman57]

Latest visible of not a hurricane Flossie. Maybe 45 kts now. NHC may only downgrade to 55-60 kts, but I don't see any evidence to support winds that high.

[BYG Jacob]

looks like she’s being decoupled

[wxman57]

:uarrow: looks like she’s being decoupled

Good news for Hawaii. I don't think it's going to be able to regain hurricane strength. Probably a remnant low by the time it nears the islands.

[NDG]

Like I have been saying this is certainly not the same EPAC as the last few years, systems have been struggling to develop and or maintain its strength.

[Astromanía]

What a dissapoint system it was forecast to be the strong one of the two right now and at the end this is not even look like an hurricane, well Erick was something that really overperform but this season still has dissapoint me so far, I don't think it will be close that we saw in 2014, 2015, 2016 and 2018 seasons, whatever looking this is better than look anything in the quiet atlantic basin

[wxman57]

The weakening continues. Maybe 35-40 kts now?

[TheStormExpert]

Wow! What happened? Yesterday strengthening was forecasted (likely to major at some point). Now it’ll be lucky to make it another day or two, doubt Flossie ever rebounds. Hawaii surely dodged a bullet yet again!

[Kingarabian]

:uarrow: Worrying that the NHC continues to say it'll likely re-strengthen.

There's a good reason why in over 200 years, only a single hurricane has survived to strike the islands from the east, the 1871 hurricane. The atmosphere is just quite hostile east of the islands. Most hurricanes weaken to a weak TS or a depression when approaching from the east.

Oh, here's a zoomed-in visible image of Flossie this morning. Crosshairs mark the center. No way in the world this is a hurricane.

http://wxman57.com/images/Flossie.JPG

I agree. The odds are always stacked against these systems. I haven't been tracking EPAC systems for too long but that's generally been the case. I first started back in 2004 when I was in the 5th grade. Prior to 2014, Hawaii threats from the EPAC that came from the east, almost always arrived as a sheared mess or a remnant low. Since 2014 something has changed and it has been a complete different story, where systems are in fact passing Hawaii to the north as hurricanes. Also, before 2014, it was unheard of to see even a TS impact the islands negatively. It wasn't atmospheric conditions that prohibited them from impacting Hawaii, it was the steering patterns. So while Flossie fortunately is likely not going to make it to Hawaii in tact, it was a possibility at some point with good reason.

[Kingarabian]

Like I have been saying this is certainly not the same EPAC as the last few years, systems have been struggling to develop and or maintain its strength.

The upper level trough north of Hawaii (is it a TUTT?) shears storms apart even during active years. So I wouldn't use what's happening to Flossie as a barometer. Although it looks like the shear is from Erick's outflow.

[Kingarabian]

As of 18:00 UTC Jul 31, 2019:
Location: 13.8°N 126.6°W
Maximum Winds: 60 kt Gusts: 75 kt
Minimum Central Pressure: 995 mb
Environmental Pressure: 1009 mb
Radius of Circulation: 180 NM
Radius of Maximum Wind: 20 NM

[Kingarabian]

Even if Flossie recovers (as the HMON and HWRF continue to indicate), models seem to be picking up on a bigger weakness and recurve Flossie away to the north. Nothing is set in stone yet, so I still encourage people to be prepared regardless.

[cycloneye]

Tropical Storm Flossie Discussion Number 14
NWS National Hurricane Center Miami FL EP072019
1100 AM HST Wed Jul 31 2019

Satellite imagery indicates that Flossie is weakening. The
low-level center is now clearly exposed to the west of the main
area of deep convection due to northwesterly wind shear. The
objective and subjective intensity estimates have been decreasing,
and the initial intensity is lowered to 60 kt based on average of
these data. This makes Flossie a tropical storm once again. Very
recent ASCAT data also supports this downgrade.

Flossie is moving westward at 14 kt, steered by a deep-layer ridge
that stretches across much of the eastern Pacific. This ridge is
expected to remain in place and should steer Flossie westward to
west-northwestward during the next several days. The track models
are tightly clustered, and the NHC forecast lies near the usually
reliable consensus aids. This forecast is slightly faster than the
previous one, and brings Flossie into the Central Pacific basin in
2-3 days and near the Hawaiian Islands by the end of the forecast
period.

The recent weakening of Flossie has been surprising since the shear
was not expected to be as strong as observed. The poor current
structure and the ongoing shear suggests that some additional
weakening is likely in the short term. However, after that time,
the global models show a more favorable upper-level wind pattern
and, since SSTs are expected to remain sufficiently warm, some
re-strengthening seems likely between 24 and 96 hours. Weakening
is forecast by the end of the period due to another increase in
shear. The NHC intensity forecast is a little lower than the
previous one and lies near the IVCN and HCCA models. However, this
intensity forecast is of lower confidence than normal.


FORECAST POSITIONS AND MAX WINDS

INIT 31/2100Z 14.0N 127.3W 60 KT 70 MPH
12H 01/0600Z 14.5N 129.4W 55 KT 65 MPH
24H 01/1800Z 15.1N 132.1W 60 KT 70 MPH
36H 02/0600Z 15.7N 135.0W 60 KT 70 MPH
48H 02/1800Z 16.3N 137.7W 65 KT 75 MPH
72H 03/1800Z 17.2N 143.2W 70 KT 80 MPH
96H 04/1800Z 18.0N 148.0W 70 KT 80 MPH
120H 05/1800Z 19.3N 152.7W 60 KT 70 MPH

$$
Forecaster Cangialosi

[Kingarabian]

Still very much a Hawaii threat based on this forecast by the NHC:



They aren't buying a sharp recurve scenario... maybe a very gradual recruve. As for Intensity, looks like they're following the dynamic models. IMO it's still 50/50. if Flossie manages to start strengthening again it could get stronger than what the HWRF and HMON are now indicating (strong cat.2), or it could remain a very weak 40kts TS.

[CyclonicFury]

I'd be very surprised if Flossie makes landfall in Hawaii at an intensity stronger than 45 knots. The waters east of Hawaii are just not favorable for TC intensification. It could bring some light showers, though.

[Kingarabian]

I'd be very surprised if Flossie makes landfall in Hawaii at an intensity stronger than 45 knots. The waters east of Hawaii are just not favorable for TC intensification. It could bring some light showers, though.

* EAST PACIFIC 2019 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* FLOSSIE EP072019 07/31/19 18 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 60 56 54 52 50 50 50 51 49 45 42 40 38
V (KT) LAND 60 56 54 52 50 50 50 51 49 45 42 40 38
V (KT) LGEM 60 57 54 52 51 49 47 45 42 38 34 30 27
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 22 20 19 20 17 13 8 13 16 18 15 22 26
SHEAR ADJ (KT) -3 -2 1 1 0 1 3 0 4 5 5 5 11
SHEAR DIR 337 343 348 352 350 327 296 276 288 290 279 277 261
SST (C) 28.0 28.0 27.8 27.7 27.5 26.9 26.9 26.7 26.8 26.8 26.3 26.6 27.0
POT. INT. (KT) 146 145 143 142 140 134 134 132 133 133 127 131 135
200 MB T (C) -52.7 -52.3 -52.4 -52.6 -52.5 -52.4 -52.4 -52.3 -52.3 -52.3 -52.6 -52.6 -53.0
200 MB VXT (C) 0.4 0.5 0.4 0.4 0.2 0.2 0.2 0.3 0.2 0.2 0.2 0.3 0.3
TH_E DEV (C) 5 5 5 5 5 5 4 4 4 4 5 5 5
700-500 MB RH 64 62 63 61 56 57 58 58 56 60 61 62 65
MODEL VTX (KT) 22 21 22 22 21 23 22 23 23 21 20 19 18
850 MB ENV VOR 20 17 15 2 -9 -7 -4 9 -1 8 12 -2 0
200 MB DIV 32 17 -5 -5 -11 -11 14 54 -16 -12 -10 -4 15
700-850 TADV -15 -17 -20 -13 -8 -5 2 -3 -3 3 7 3 4
LAND (KM) 1935 2018 2086 2155 2231 2181 1900 1584 1286 1011 757 485 192
LAT (DEG N) 13.8 14.2 14.5 14.9 15.2 15.7 16.1 16.7 17.0 17.3 17.6 18.2 19.2
LONG(DEG W) 126.6 127.9 129.2 130.5 131.8 134.6 137.2 140.1 142.9 145.5 147.9 150.4 153.0
STM SPEED (KT) 13 13 13 13 13 13 14 14 13 12 12 13 13
HEAT CONTENT 17 18 15 16 12 21 19 3 4 8 1 3 14

26.5C waters are more than enough to support TC intensification. We've seen storms intensify in this region with cooler SST's. If it's to remain weak as it approaches Hawaii, it has to be from shear which is more plausible.

[NDG]

Throw out the HWRF out the window past 24 hours, the same model just two days ago was showing Flossie to be a MH this afternoon.
Flossie looks like it will find better UL winds over the next few days but both the GFS and Euro show a wall of windshear as it approaches Hawaii thanks to the usual TUTT near Hawaii.
I don't see this being a hurricane threat to Hawaii other than a weak TS, just my amateur opinion.