WPAC: HONE - Post-Tropical - Discussion

[tolakram]

saved loops

[MarioProtVI]

Quite the storm - the Hone memes paid off, but looks like it’s weakening now as it passes south of the Big Island and downsloping air chokes it off.

[cycloneye]

Hurricane Hone Discussion Number 13
NWS Central Pacific Hurricane Center Honolulu HI CP012024
500 AM HST Sun Aug 25 2024

Hone is passing by around 40 nautical miles south of South Point on
the Big Island of Hawaii this morning, where it is within radar
range. Combined radar, and data from an Air Force Reserve
reconnaissance aircraft mission earlier this morning, support
raising the initial intensity of Hone to 75 knots, keeping it a
Category 1 Hurricane. Despite recent subjective Dvorak estimates
suggesting a slightly lower intensity, the satellite presentation
has evolved markedly overnight, with cold cloud tops near -75 C
reinforcing the radar and aircraft-based intensities. The initial
intensity is raised to 75 kt for this advisory.

The initial motion of Hone is set at 280/07. This westward
trajectory is expected to persist over the coming days, influenced
by a subtropical ridge to the north. However, as Hone remains near
the Big Island through the early morning hours today, the
mountainous terrain could influence local steering currents,
potentially leading to localized and short-term deviations in the
storm's motion and intensity. As we move into the early to mid
portion of the week, Hone is projected to encounter increasing
vertical wind shear, which is expected to weaken the storm and make
it more shallow. This change in conditions will allow the low-level
trade wind flow to steer the system toward the west-southwest. The
official forecast track remains nearly identical to the previous
advisory and is closely aligned with the tightly clustered consensus
guidance.

Environmental conditions affecting Hone will remain steady over the
next 12 to 24 h, with sea surface temperatures between 26 C and 27
C, light to moderate vertical wind shear, and sufficient mid-level
moisture. This supports maintaining a steady trend in intensity
through the morning hours today. Although sea surface temperatures
are forecast to rise to around 27 C tonight and beyond as Hone
continues westward, increasing vertical wind shear will translate to
a gradual weakening trend later today through the middle of the
week. The intensity forecast closely follows dynamical consensus
guidance.

KEY MESSAGES:

1. Tropical Storm conditions will continue on the Big Island through
the morning hours. Winds are expected to be strongest downslope of
higher terrain, over headlands, and through passes.

2. Hone is expected to produce storm total rainfall of 6 to 12
inches over mainly windward and southeast facing slopes of the Big
Island, with locally higher amounts possible. Rainfall totals of 2
to 4 inches will be possible over portions of the smaller islands,
mainly windward.

3. Swells generated by Hone will continue today as this system
continues westward. Expect dangerous conditions with
life-threatening surf and rip currents.


FORECAST POSITIONS AND MAX WINDS

INIT 25/1500Z 18.3N 156.1W 75 KT 85 MPH
12H 26/0000Z 18.6N 157.8W 70 KT 80 MPH
24H 26/1200Z 18.9N 160.1W 60 KT 70 MPH
36H 27/0000Z 19.0N 162.4W 55 KT 65 MPH
48H 27/1200Z 19.1N 164.6W 50 KT 60 MPH
60H 28/0000Z 19.4N 166.8W 50 KT 60 MPH
72H 28/1200Z 19.7N 168.5W 45 KT 50 MPH
96H 29/1200Z 20.5N 172.0W 40 KT 45 MPH
120H 30/1200Z 20.6N 175.0W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Jelsema/Gibbs

[cycloneye]

Hurricane Hone Discussion Number 14
NWS Central Pacific Hurricane Center Honolulu HI CP012024
1100 AM HST Sun Aug 25 2024

Data from a U.S. Air Force Reserve Hurricane Hunter aircraft
confirm what can be deduced from latest satellite images, that Hone
has weakened since undergoing a period of intensification last
night. The pressure has been rising slowly over the course of this
morning's mission, and the highest flight-level winds thus far have
been 67 kt. The initial intensity estimate for this advisory has
been lowered, perhaps conservatively, to 70 kt.

The initial motion estimate is 290/12kt, as Hone's forward speed
has increased somewhat since the previous advisory. Recent jogs in
the observed track may have been related to the high terrain of the
Big Island, but as it continues to move away, Hone's general
westward motion will be imparted by a low- to mid-level ridge to the
north. The updated forecast track is close to the previous, after
accounting for a northwesterly jog as Hone passed south of the Big
Island, and most closely follows the dynamical consensus models.

Water vapor and infrared satellite images show that Hone lies in
a col between upper-level ridges centered to the distant east-
northeast and west. This pattern has been providing enhanced
outflow aloft over the last 12-18 hours, likely aiding in the
observed intensification to a hurricane. The forecast track will
take Hone north of the upper-level ridge axis to its west, and into
an area of increased westerly vertical wind shear, especially after
Tuesday. Despite steadily increasing SSTs along the forecast
track, the forecast anticipates that Hone will weaken due
to the shear. The intensity forecast generally follows the
trends presented by the intensity consensus, and anticipates that
Hone will dissipate before exiting the central Pacific basin.


KEY MESSAGES:

1. Tropical Storm conditions will continue on the Big Island
into the early afternoon, with gradually diminishing wind and
rainfall through the evening. Winds will strongest downslope of
higher terrain, over headlands, and through passes.

2. Hone will continue to deliver persistent and locally
widespread rainfall to portions of the Hawaiian islands.

3. Swells generated by Hone are affecting portions of the
Hawaiian islands, producing life-threatening surf and rip
current conditions.


FORECAST POSITIONS AND MAX WINDS

INIT 25/2100Z 18.8N 157.3W 70 KT 80 MPH
12H 26/0600Z 19.1N 159.0W 65 KT 75 MPH
24H 26/1800Z 19.3N 161.3W 60 KT 70 MPH
36H 27/0600Z 19.3N 163.6W 55 KT 65 MPH
48H 27/1800Z 19.5N 165.9W 50 KT 60 MPH
60H 28/0600Z 19.9N 168.1W 50 KT 60 MPH
72H 28/1800Z 20.3N 170.4W 45 KT 50 MPH
96H 29/1800Z 21.1N 174.7W 35 KT 40 MPH
120H 30/1800Z...DISSIPATED

[cycloneye]

Tropical Storm Hone Discussion Number 16
NWS Central Pacific Hurricane Center Honolulu HI CP012024
1100 PM HST Sun Aug 25 2024

Hone appears quite disorganized on satellite and radar this
evening. However, the earlier exposed low level circulation center
is once again obscured by layered cloud, and a ragged band of deep
convection has redeveloped around a portion of the low level
circulation center. The current intensity has been reduced to 60 kt,
which is a blend of the unanimous data-T numbers and current
intensity estimates from the fix agencies. This could be generous,
given Hone's messy appearance.

The initial motion is 280/12. Deep layer ridging to the north of
Hone is expected to maintain the system on a westerly track the
next few days. Later in the forecast period, Hone is expected to be
increasingly steered by the low level tradewind flow to the south
of a vast subtropical ridge spanning much of the Pacific. The track
guidance remains tightly clustered and the latest official forecast
is very similar to the previous.

The UW-CIMSS shear analysis shows Hone is already in an environment
of moderate shear. Over the next few days, Hone will continue to
skirt along the southern periphery of the subtropical jet,
subjecting the system to increasing westerly shear. This should
continue the weakening trend, despite a gradual increase in sea
surface temperatures along the forecast track. The intensity
forecast continues to agree well with the statistical and dynamical
guidance, and dissipation is expected as a remnant low late in the
week.

Mahalo to both the U.S. Air Force Reserve and NOAA Hurricane
Hunters for gathering much critical data from Tropical Cyclone Hone
the last few days.

FORECAST POSITIONS AND MAX WINDS

INIT 26/0900Z 19.3N 159.7W 60 KT 70 MPH
12H 26/1800Z 19.4N 161.4W 55 KT 65 MPH
24H 27/0600Z 19.6N 163.7W 50 KT 60 MPH
36H 27/1800Z 19.8N 166.1W 45 KT 50 MPH
48H 28/0600Z 20.1N 168.4W 45 KT 50 MPH
60H 28/1800Z 20.5N 170.8W 40 KT 45 MPH
72H 29/0600Z 20.9N 173.0W 35 KT 40 MPH
96H 30/0600Z 21.6N 177.1W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 31/0600Z...DISSIPATED

$$
Forecaster R Ballard

[cycloneye]

Tropical Storm Hone Discussion Number 17
NWS Central Pacific Hurricane Center Honolulu HI CP012024
500 AM HST Mon Aug 26 2024

Moderate westerly shear is continuing to take a toll on Hone. The
low level circulation appears to be partly exposed and the center
is likely near the western edge of an earlier burst of convection.
PHFO and JTWC subjective intensities were 3.5, which agrees well
with UW-CIMSS SATCON and AiDT. The initial intensity was lowered to
55 kt with this advisory.

Hone continues to move just north of due west, 280/11, to the south
of deep layer ridging. This general motion should persist for the
next several days and the track guidance is still relatively
tightly clustered. The current forecast is very similar to the
previous forecast track. Although Hone will be moving over warmer
sea surface temperatures, increasingly strong shear through the
forecast period will continue to gradually weaken the tropical
cyclone. Later in the forecast period, the low level trade wind
flow will continue to take the shallow circulation of Hone on a
westward journey. Most of the guidance shows a slightly slower
forward speed prior to expected dissipation. The intensity forecast
continues to be a blend of the statistical and dynamical guidance,
and very similar to the previous forecast package. Hone should
become a remnant low in about 4 days prior to dissipation as it
approaches the International Date Line.


FORECAST POSITIONS AND MAX WINDS

INIT 26/1500Z 19.4N 161.0W 55 KT 65 MPH
12H 27/0000Z 19.5N 162.9W 55 KT 65 MPH
24H 27/1200Z 19.6N 165.2W 50 KT 60 MPH
36H 28/0000Z 19.9N 167.5W 45 KT 50 MPH
48H 28/1200Z 20.3N 169.8W 45 KT 50 MPH
60H 29/0000Z 20.7N 172.0W 40 KT 45 MPH
72H 29/1200Z 21.1N 174.2W 35 KT 40 MPH
96H 30/1200Z 21.7N 178.1W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 31/1200Z...DISSIPATED

$$
Forecaster R Ballard

[Hayabusa]

Recent GFS runs reintensify Hone as it enters the Western Pacific.

[Hayabusa]

Recent GFS runs reintensify Hone as it enters the Western Pacific.

Latest 12Z Euro also

[Kingarabian]

SSTs above average in that area. Very possible.

[Teban54]

 https://x.com/weatherman_aaa/status/1828954845920817330

[Hurricane2022]

Very interesting discussion in the 21z advisory.

The strong vertical shear affecting Hone is not expected to abate over the next 3 days. However, SSTs beneath the tropical cyclone are very warm, which may keep deep convection active, resulting in the maintenance of an asymmetric tropical storm through at least the next couple of days. The consensus of the objective aids shows a slow weakening over the next couple of days, but a slight increase in strength from day 3 onward. The FSU phase space diagrams for the various global models keep Hone as a warm core system even after interacting with the upper tropospheric low. For now, the forecast maintains Hone as a tropical storm a little longer than the previous package, then maintains it as a post-tropical cyclone through day 5. It should be noted that there is a possibility Hone may survive as a tropical cyclone and even intensify to a typhoon west of the International Date Line.

[xtyphooncyclonex]

At the end of the forecast period, Hone is forecast
to intensify, with several models showing an increase to typhoon strength beyond 120 hours west of the International Date Line.

NHC even more assertive with strengthening this advisory. See you in a week, typhoon Hone.

[wxman57]

At the end of the forecast period, Hone is forecast
to intensify, with several models showing an increase to typhoon strength beyond 120 hours west of the International Date Line.

NHC even more assertive with strengthening this advisory. See you in a week, typhoon Hone.

It's the CPHC making the forecasts. NHC stops at 140W. Sure miss Levi's website. Our in-house model data is no more than stick figures, and it doesn't handle crossing the Date Line.

[xtyphooncyclonex]

Quite a marked change from two days ago.

The intensity forecast calls for gradual strengthening
Friday night through the remainder of the forecast, with Hone
nearing Typhoon strength early next week to the west of the
International Date Line. The intensity forecast was adjusted
downward slightly during the next 36 hours, then adjusted upward a tad beyond 36 hours to better align with the latest consensus guidance.

[Hurricane2022]

We realize that the CPHC is quite happy to have its own named storm in its own basin

One of the Hawaiian definitions for Hone is mischievous, or to tease. Certainly Hone has been living up to its namesake as both the track, and especially the intensity forecast, remain quite challenging and complex. A low aloft, seen in water vapor about 270 nm north of Midway Atoll, is expected to dig southward. Hone's initial motion estimate is 290/6. The low level circulation, which has been moving west-northwest for quite some time, is expected to be pulled northwestward toward this low aloft and eventually get entangled with the circulation of the upper low. This will pull the low-level circulation of Hone more toward the north-northwest in a couple of days, and then as Hone and the mid- and upper-level circulation become aligned, resume a west-northwest motion over the western Pacific. There is decent agreement in the model guidance, given this rather complex interaction. The official forecast was nudged slightly more northward, toward TVCN and HCCA, but still close to the previous track. It should be noted that in the longer range, there are rather large differences in forward speed among the various guidance, with the models trending slower. At these time periods, the official forecast points were slowed down somewhat in deference to the guidance consensus, TVCN.
If Hone can survive its current battle with westerly shear, there appears to be an opportunity for reintensification. The global models and SHIPS guidance suggest that the strong shear currently over Hone will eventually relax, and sea surface temperatures at that time will also be supportive of strengthening. The global models show a warm core redeveloping over Hone over the west Pacific in a few days, after the low levels and circulation aloft become well aligned. However, there is considerable variability among the guidance. The intensity forecast most closely follows IVCN, but it should be noted uncertainty is quite high.

[Hayabusa]

Pretty eye catching in a non El Nino state that there's a crossover TC entering the Western Pacific that would strengthen (possibly up to typhoon strength) instead of weakening

[Kingarabian]

We realize that the CPHC is quite happy to have its own named storm in its own basin

One of the Hawaiian definitions for Hone is mischievous, or to tease. Certainly Hone has been living up to its namesake as both the track, and especially the intensity forecast, remain quite challenging and complex. A low aloft, seen in water vapor about 270 nm north of Midway Atoll, is expected to dig southward. Hone's initial motion estimate is 290/6. The low level circulation, which has been moving west-northwest for quite some time, is expected to be pulled northwestward toward this low aloft and eventually get entangled with the circulation of the upper low. This will pull the low-level circulation of Hone more toward the north-northwest in a couple of days, and then as Hone and the mid- and upper-level circulation become aligned, resume a west-northwest motion over the western Pacific. There is decent agreement in the model guidance, given this rather complex interaction. The official forecast was nudged slightly more northward, toward TVCN and HCCA, but still close to the previous track. It should be noted that in the longer range, there are rather large differences in forward speed among the various guidance, with the models trending slower. At these time periods, the official forecast points were slowed down somewhat in deference to the guidance consensus, TVCN.
If Hone can survive its current battle with westerly shear, there appears to be an opportunity for reintensification. The global models and SHIPS guidance suggest that the strong shear currently over Hone will eventually relax, and sea surface temperatures at that time will also be supportive of strengthening. The global models show a warm core redeveloping over Hone over the west Pacific in a few days, after the low levels and circulation aloft become well aligned. However, there is considerable variability among the guidance. The intensity forecast most closely follows IVCN, but it should be noted uncertainty is quite high.

I like the way they've been writing and going about their discussions the past couple of years.

[Hayabusa]

18Z HFSA makes it a major

[cycloneye]

Tropical Depression Hone Discussion Number 31
NWS Central Pacific Hurricane Center Honolulu HI CP012024
500 PM HST Thu Aug 29 2024

Hone has been nearly devoid of deep convection since about 2300
UTC, and the low level circulation center has been fully exposed
for the last several hours. ASCAT-C at 2051 UTC sampled 30 kt winds
to the north of the low level center. The subjective intensity
estimates were 2.0 from PHFO and JTWC, and 2.5 from SAB. The
objective Dvorak estimates have also been trending downward. Thus
the intensity is reduced to 30 kt for this advisory, and Hone is a
tropical depression once again.

Both the track and the intensity forecast remain quite challenging
for mischievous Hone. Hone has been persistently moving
west-northwest on its trek across the central Pacific, and the
motion for this advisory was 280/7. However, a low aloft, seen in
water vapor imagery about 270 nm north of Midway Atoll, is expected
to dig generally southward over the next couple of days. Hone is
expected to be pulled northwestward toward this feature in about 48
hours and get entangled with the upper circulation. After Hone and
the upper low become aligned, the tropical cyclone is expected to
resume a west-northwest motion over the western Pacific, although
the models differ in forward speed toward the end of the forecast
period. Despite the rather complex interaction among the two
features, there is decent agreement in the model guidance through
the next 3 days or so, and the forecast continues to lie near the
TVCN consensus guidance. All of this assumes, of course, that
renewed deep convection in a day or two will allow Hone to gain
latitude as a deeper system once again.

If Hone manages to survive its current battle with 45 kt of
westerly shear as analyzed by UW-CIMSS, there appears to be an
opportunity for reintensification. The global models and SHIPS
guidance suggest that the strong shear currently over Hone will
eventually relax, and sea surface temperatures at that time will
also be supportive of strengthening. The global models show deep
convection reestablishing a warm core with Hone over the west
Pacific in a few days, once the lower and upper features merge.
However, there remains considerable spread among the guidance
in how much Hone is able to restrengthen after that happens. The
intensity forecast generally follows the trend of IVCN, but it
should be noted uncertainty is very high by the end of the forecast
period.


FORECAST POSITIONS AND MAX WINDS

INIT 30/0300Z 21.5N 173.3W 30 KT 35 MPH
12H 30/1200Z 21.8N 174.4W 30 KT 35 MPH
24H 31/0000Z 22.4N 175.5W 30 KT 35 MPH
36H 31/1200Z 23.2N 176.3W 35 KT 40 MPH
48H 01/0000Z 24.5N 176.9W 40 KT 45 MPH
60H 01/1200Z 25.7N 178.2W 45 KT 50 MPH
72H 02/0000Z 26.5N 179.8W 50 KT 60 MPH
96H 03/0000Z 27.4N 177.2E 55 KT 65 MPH
120H 04/0000Z 29.0N 174.3E 60 KT 70 MPH

$$
Forecaster R Ballard/Foster

[Teban54]

The joke continues:

Both the track and the intensity forecast remain quite challenging for mischievous Hone.