CPAC: LANE - Post-Tropical

[Kingarabian]

Looks like most of us busted on our forecasts for Lane. Arguably 145kts at one point.

Overall the CPHC/models had Lane weakening and staying offshore. Not sure it was a bust.

I think he was referring to the early days when most of us were guessing 120kts at peak "typical fish Cat 4 major"

Yes, I meant Storm2k members.

In regards to the CPHC track for Lane, I didn't have problems with it other than them keeping Lane as a hurricane moving west. In the end, they did a really good job with Lane's track. But I see why they had it as a hurricane. They were simply interpolating Dvorak estimates which would keepthe storms intensity near or @ hurricane strength, although that's a questionable method as Wxman57, Tolakram, and NDG explained nicely how the system was likely much weaker at that point.

[bob rulz]

The re-analysis for this one will definitely be interesting. Without recon towards the end, intensity estimates were very tricky.

So I know that southwesterly shear of 20+ knots was the primary reason for the demise of this hurricane, but what's the concensus on the impact of the volcanoes on the Big Island? Do the mountains choke off enough outflow to cause hurricanes that come nearby to collapse so quickly? Or if the shear were favorable, would it have been able to hold together? On satellite it certainly did appear that it started rapidly falling apart as soon as the circulation center crossed the latitude of the 13,000+ ft volcanoes on the Big Island, but it could just be coincidence. Or does nobody really know for sure?

[tolakram]

It appears to be moving a little south of west. Hopefully it drags the rain with it.

https://weather.msfc.nasa.gov/cgi-bin/get-goes?satellite=GOES-W%20PACUS&lat=19&lon=-158&zoom=1&width=1000&height=800&type=Animation&quality=85&info=vis&palette=ir1.pal&numframes=25&mapcolor=yellow

[wxman57]

23Z ASCAT pass confirms Lane is a depression. Max wind 30kts NE-SE, and about 15 kts elsewhere.

Just a naked swirl now.

[Twisted-core]

https://imgur.com/jVvwmoz

Best Track Position and Intensity as of:

Sunday, Aug. 26, 2018 0:00 Z

Wind (1 min. avg.):

45 knots (52 mph | 23 m/s | 83 km/h)

Pressure:

998 mb (29.47 inHg | 998 hPa)

Location at the time:

173 statute miles (279 km) to the S (189°) from Lihue, on the island of Kauai, HI, USA.

Coordinates:

19.5N 159.8W

[cycloneye]

BULLETIN
Tropical Storm Lane Advisory Number 47
NWS Central Pacific Hurricane Center Honolulu HI EP142018
500 PM HST Sat Aug 25 2018

...LANE CONTINUES TO MOVE WEST AWAY FROM THE MAIN HAWAIIAN
ISLANDS...


SUMMARY OF 500 PM HST...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...19.5N 160.2W
ABOUT 195 MI...310 KM SW OF HONOLULU HAWAII
ABOUT 180 MI...290 KM SSW OF LIHUE HAWAII
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES



Tropical Storm Lane Discussion Number 47
NWS Central Pacific Hurricane Center Honolulu HI EP142018
500 PM HST Sat Aug 25 2018

The low level circulation center of Lane is exposed in visible
satellite imagery with bursts of deep convection continuing to pulse
east of the low level center. Based on the latest Dvorak fixes and
the latest satellite representation of Lane, we have maintained the
initial intensity at 45 knots with this advisory. Wind radii were
decreased slightly based on a recent ASCAT pass which captured the
eastern side of the circulation.

Strong westerly shear of 30 to 40 kt continues to impact lane.
Gradual weakening is forecast over the next couple of days due to
this strong shear persisting. This follows closely with ICON and
SHIPS guidance. Lane is forecast to weaken to a depression in about
36 hours and to a remnant low by 72 hours. Assuming this low
survives, it may eventually become an extratropical gale low in the
vicinity of the Northwestern Hawaiian Islands around days 4 and 5.

The latest motion for this advisory is 270/8 knots. A slight
increase in forward is expected over the next couple of days as the
low level center remains embedded in the trades south of an area of
high pressure north of Hawaii. By day 3, a turn to the northwest is
expected the the system rounds the southwest side of the high. The
current track forecast has been nudged to the left through 48 hours,
with little change from days 3 through 5. This forecast closely
follows the HWRF, and lies close to the consensus models.

FORECAST POSITIONS AND MAX WINDS

INIT 26/0300Z 19.5N 160.2W 45 KT 50 MPH
12H 26/1200Z 19.4N 161.4W 40 KT 45 MPH
24H 27/0000Z 19.2N 163.1W 35 KT 40 MPH
36H 27/1200Z 19.1N 164.6W 30 KT 35 MPH
48H 28/0000Z 19.6N 166.0W 30 KT 35 MPH
72H 29/0000Z 22.5N 168.2W 30 KT 35 MPH
96H 30/0000Z 26.6N 170.8W 35 KT 40 MPH...POST-TROPICAL
120H 31/0000Z 31.4N 175.4W 35 KT 40 MPH...POST-TROP/EXTRATROP

$$
Forecaster Burke

[galaxy401]

Eastern part of the Big Island is getting constant downpours again. Seems that part of Lane is lingering there, maybe the mountains are cutting it off from the system.

[cycloneye]

Tropical Storm Lane Discussion Number 48
NWS Central Pacific Hurricane Center Honolulu HI EP142018
1100 PM HST Sat Aug 25 2018


After a burst of deep convection that started late last night and
continued through this morning, the low-level circulation center
(LLCC) of Lane became exposed this afternoon. The thunderstorms
were quickly sheared away from the center as Lane is embedded in an
area characterized by 40-50 kt of vertical wind shear. Subjective
Dvorak Data-T numbers were unavailable due to the lack of convection
near the center, but current intensities ranged from 2.0/30 kt to
2.5/35 kt. Given that we've seen these recently-exposed LLCCs
produce tropical-storm-force winds in the past, the initial
intensity is estimated to be 35 kt for this advisory.

The initial motion for this advisory is 260/7 kt. Lane is being
driven westward by the low-level trade wind flow supplied by a
surface high to the distant northeast. Track guidance is in good
agreement in the short term, with Lane tracking generally toward
the west through 36 hours. Thereafter, guidance spread increases
somewhat but not dramatically, and generally shows a brief slowing
in forward speed before an accelerated motion toward the northwest
evolves. This occurs as Lane interacts with a developing mid-level
low to its west. The updated track forecast is very close to the
previous, and lies close to the multi-model consensus TVCE.

With deep convection absent near Lane's center for several hours,
the clock is ticking on Lane's status as a tropical cyclone. While
the updated forecast anticipates that brief deep convective pulses
will occasionally occur in association with Lane, these are not
expected to develop over the center, and Lane is now expected to
become a post-tropical remnant low by late Sunday. Thereafter, Lane
is expected to track toward the west as a weak post-tropical
remnant low. Assuming Lane survives as a coherent feature, it is
then expected to interact with a developing low aloft and transition
to an extratropical low by Tuesday/Wednesday. This low could bring
gale force winds to portions of the Northwestern Hawaiian Islands
around the middle of the week.

Around 8 pm HST, Lane passed very close to NOAA buoy 51003, which
reported a minimum pressure of 1005 mb and seas just below 12 feet.
These data were used to fine tune the analysis.

FORECAST POSITIONS AND MAX WINDS

INIT 26/0900Z 19.3N 161.2W 35 KT 40 MPH
12H 26/1800Z 19.4N 162.3W 30 KT 35 MPH
24H 27/0600Z 19.3N 163.8W 30 KT 35 MPH...POST-TROPICAL
36H 27/1800Z 19.5N 165.5W 25 KT 30 MPH...POST-TROPICAL
48H 28/0600Z 20.0N 166.2W 25 KT 30 MPH...POST-TROPICAL
72H 29/0600Z 23.6N 168.5W 30 KT 35 MPH...POST-TROP/EXTRATROP
96H 30/0600Z 28.5N 172.5W 40 KT 45 MPH...POST-TROP/EXTRATROP
120H 31/0600Z 33.0N 177.5W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Birchard

[tolakram]

I'd say it's over.

https://weather.msfc.nasa.gov/cgi-bin/get-goes?satellite=GOES-W%20PACUS&lat=19&lon=-159&zoom=1&width=1000&height=800&type=Animation&quality=85&info=ir&palette=ir5.pal&numframes=25&mapcolor=yellow

Unfortunately a lot of rain still falling in places. Saved loop.

[cycloneye]

Going to be downgraded.

Tropical Depression LANE
As of 12:00 UTC Aug 26, 2018:

Location: 19.2°N 161.7°W
Maximum Winds: 30 kt Gusts: N/A
Minimum Central Pressure: 1006 mb
Environmental Pressure: 1010 mb
Radius of Circulation: 100 NM
Radius of Maximum Wind: 60 NM

[galaxy401]

Lane is now the third wettest tropical cyclone to hit the US, second in Hawaii. Fortunately, no deaths have been reported yet.

[Ptarmigan]

Interesting to note that Lane happens a year after Harvey.

[cycloneye]

Tropical Depression Lane Discussion Number 50
NWS Central Pacific Hurricane Center Honolulu HI EP142018
1100 AM HST Sun Aug 26 2018

The low-level circulation center of Lane remains exposed with
bursts of deep convection continuing to pulse in the northeast
quadrant. The once powerful cyclone is in the process of becoming a
post-tropical remnant low, as it remains embedded in a hostile
environment, with vertical wind shear of around 40 knots impacting
the system. The initial intensity for this advisory remains at 30 kt
based on the latest Dvorak intensity estimates. Based on an
overnight ASCAT pass, these winds are mainly in the northern
semicircle of the circulation.

The initial motion for this advisory is 270/9 kt. A surface high to
the distant northeast will keep Lane moving generally toward the
west into Monday as it devolves into a post-tropical remnant low
later today or tonight. Once Lane becomes post-tropical,
redevelopment into a tropical cyclone is highly unlikely. A brief
slowing in forward speed is expected Monday night as the remnant
low reaches the southwestern edge of the high and begins to
interact with a developing mid-level low to its west. Assuming Lane
survives as a coherent feature until then, this interaction is
expected to lead to the development of an extratropical low by
Tuesday or Wednesday. This low could bring gale force winds to
portions of the Papahanaumokuakea Marine National Monument as it
tracks north and northwest around the middle of the week. The latest
official forecast track is close to the TVCE consensus while the
intensity forecast is supported by global model guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 26/2100Z 19.1N 163.2W 30 KT 35 MPH
12H 27/0600Z 18.9N 164.7W 30 KT 35 MPH
24H 27/1800Z 19.0N 166.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
36H 28/0600Z 19.4N 167.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 28/1800Z 20.4N 167.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 29/1800Z 25.0N 169.8W 35 KT 40 MPH...POST-TROP/EXTRATROP
96H 30/1800Z 30.6N 174.3W 40 KT 45 MPH...POST-TROP/EXTRATROP
120H 31/1800Z 34.0N 179.0W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Burke

[cycloneye]

LANE makes a comeback.

EP, 14, 2018082712, , BEST, 0, 189N, 1650W, 35, 1004, TS

[tolakram]

Just about out of range of this loop.

https://weather.msfc.nasa.gov/cgi-bin/get-goes?satellite=GOES-W%20PACUS&lat=19&lon=-165&zoom=1&width=1000&height=800&type=Animation&quality=85&info=ir&palette=ir5.pal&numframes=25&mapcolor=yellow

SLIDER
http://rammb-slider.cira.colostate.edu/?sat=himawari&sec=full_disk&x=19815&y=7053&z=4&im=12&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=0&p%5B0%5D=12&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=0&mouse_draw=0&s=rammb-slider

[cycloneye]

LANE is resilant

Tropical Storm Lane Discussion Number 53
NWS Central Pacific Hurricane Center Honolulu HI EP142018
500 AM HST Mon Aug 27 2018

Lane's low-level circulation center had been exposed for the better
part of the last 30 hours, as the cyclone remains in an environment
characterized by 40 kt of vertical wind shear. However, a recent
vigorous convective burst in the eastern semicircle has at least
partially obscured the low-level center, and convective banding has
increased to the southeast. Subjective Dvorak intensity estimates
trended up, but were still primarily 2.0/30 kt at the synoptic time,
while UW-CIMSS SATCON was near 35 kt. With the improved satellite
appearance since then, and since an ASCAT pass detected winds just
over 30 kt on Sunday, the initial intensity for this advisory is
increased to 35 kt, and Lane is once again a tropical storm.

The initial motion for this advisory is 270/7 kt, with Lane being
driven westward by a surface high to the distant northeast. This
motion will continue in the short-term, with Lane's forward motion
expected to diminish tonight as it reaches the southwestern edge of
the high. At the same time, increased interaction with an
amplifying mid-level low will likely lead to a deepening shear
profile, with the strong shear currently in the upper-levels
spreading to the mid-levels. This should be more effective in
interrupting Lane's low-level core, and Lane is expected to become a
post-tropical remnant low by Tuesday.

Lane is forecast to become an extratropical low later Tuesday into
Wednesday as it gets wrapped up into the circulation associated
with the mid-level low. This extratropical low could then bring
gale force winds to portions of the Papahanaumokuakea Marine
National Monument as it tracks north and northwest. The updated
track forecast has been shifted to the left of the previous,
especially in the later periods, to be better in line with GFEX. The
intensity forecast represents a blend of regional and global model
guidance.

FORECAST POSITIONS AND MAX WINDS

INIT 27/1500Z 18.9N 165.5W 35 KT 40 MPH
12H 28/0000Z 19.0N 166.3W 30 KT 35 MPH
24H 28/1200Z 19.6N 167.2W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 29/0000Z 21.0N 168.2W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 29/1200Z 23.2N 169.2W 35 KT 40 MPH...POST-TROP/EXTRATROP
72H 30/1200Z 29.0N 174.5W 40 KT 45 MPH...POST-TROP/EXTRATROP
96H 31/1200Z 32.0N 177.5W 40 KT 45 MPH...POST-TROP/EXTRATROP
120H 01/1200Z 34.6N 180.0E 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Birchard

[AnnularCane]

Not going down without a fight!

[wxman57]

All that remains is a swirl of low clouds. Bones has called it. Time - 1939 UTC August 27th

[wxman57]

I thought the title of this thread was a mistake - Lane TS?? I do not understand the reasoning for an upgrade. It's a swirl of low clouds devoid of any convection. No inflow. I'm speechless...

[DioBrando]

lane be singing "guess who's back back again"