WPAC: MERANTI - Post-Tropical

[dexterlabio]

Just looked back at the time when I said Meranti does not compare to the 2014 trio (Hagupit, Vongfong, Nuri).. and I'd gladly eat crow for that one..

This is quite different than the other STYs that approached Taiwan and Batanes area..usually they reach their peak far away from land, but Meranti was looking at its best the time it was over the Batanes island chain.

[1900hurricane]

VIIRS Nighttime Visible of Meranti as it was crossing Itbayat.

[euro6208]

16W MERANTI 160914 0000 21.6N 120.7E WPAC 155 900

Down to 155 knots...

[euro6208]

VIIRS Nighttime Visible of Meranti as it was crossing Itbayat.

Beautiful but scary. Shined by the precious moonlight then all hell breaks loose as the outer most destructive eyewall.

[1900hurricane]

This is the seventh intensity estimate from JTWC of 155 kt or higher (CI 7.5+), or 1.75 days worth of time. This ties Angela '95 for the longest time to meet this criteria in the entirity of the post-recon era beginning in 1987.

[euro6208]

[1900hurricane]

Meranti has actually drifted really close to Taiwan recently.

[euro6208]

Usually storms of this intensity are way out over the ocean east of the Philippines and Taiwan.

Likely the strongest ever typhoon to cross the Luzon strait...

[1900hurricane]

Usually storms of this intensity are way out over the ocean east of the Philippines and Taiwan.

Likely the strongest ever typhoon to cross the Luzon strait...

James Reynolds seems to think so.

 https://twitter.com/EarthUncutTV/status/775868845277843456

[mrbagyo]

Big bite on that Northwestern eyewall, Pintung and Kaohsiung will likely get some beating.

[euro6208]

Looks like just another day in Kaohsiung with people and cars roaming the streets while a Cat 5 passes south of them...

http://www.taiwanrider.com/webcam/cam_1s.html

[euro6208]

WDPN31 PGTW 140300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 16W (MERANTI) WARNING NR
22//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUPER TYPHOON (STY) 16W (MERANTI), LOCATED APPROXIMATELY 215 NM
SOUTH-SOUTHWEST OF TAIPEI, TAIWAN, HAS TRACKED NORTHWESTWARD AT 13
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTED A NORTHWARD WOBBLE IN THE STORM MOTION AS THE
CYCLONE APPROACHED TAIWAN. INTERACTION WITH THE SOUTHERN TIP OF
TAIWAN CREATED A TEMPORARY CLOUD FILLED EYE WHICH HAS SINCE STARTED
CLEARING. DEEP CONVECTIVE BANDING ALONG THE NORTHERN SIDE OF THE
SYSTEM IS PUSHING ONSHORE NEAR CENTRAL TAIWAN. A 132327Z SSMIS 91GHZ
IMAGE DEPICTS BROAD DEEP CONVECTION EXTENDING 100NM TO THE SOUTH OF
THE EYE. THE SSMIS IMAGE ALSO CONTINUES TO DEPICT AN EYEWALL
REPLACEMENT CYCLE; HOWEVER, THE OUTER CONVECTIVE RING HAS BEEN
DISRUPTED BY LAND INTERACTION. THE CURRENT POSITION IS BASED ON THE
EYE FEATURE IN SATELLITE AND THE TAIWAN RADAR WITH HIGH CONFIDENCE.
THE INTENSITY HAS BEEN DECREASED DUE TO LAND INTERACTION WITH
SOUTHERN TAIWAN AND IS SUPPORTED BY CURRENT INTENSITY FIXES OF T7.5
(155 KNOTS) FROM ALL AGENCIES. STY 16W MAINTAINS A VERY FAVORABLE
ENVIRONMENT WITH LOW VERTICAL WIND SHEAR (VWS), STRONG RADIAL
OUTFLOW, AND VERY WARM SEA SURFACE TEMPERATURES. HOWEVER, THE LAND
INTERACTION WITH TAIWAN AND THE EYEWALL REPLACEMENT CYCLE WILL
OFFSET THE FAVORABLE ENVIRONMENT. STY 16W IS UNDER THE STEERING
INFLUENCE OF A SUBTROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
A. NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. STY 16W IS FORECAST TO CONTINUE ON ITS OVERALL NORTHWESTWARD
MOVEMENT THROUGHOUT THE FORECAST UNDER THE STEERING INFLUENCE OF THE
STR; HOWEVER, EXPECT CONTINUED TROCHOIDAL EYE MOTION WHICH WILL
CAUSE FLUCTUATIONS IN THE STORM TRACK. THE COMBINED EFFECTS OF
INCREASING VWS, LAND INTERACTION, AND THE EYEWALL REPLACEMENT CYCLE
WILL ALL SERVE TO WEAKEN THE SYSTEM AS IT APPROACHES CHINA. JUST
BEFORE TAU 24, STY MERANTI WILL MAKE LANDFALL IN CHINA AS A STRONG
TYPHOON. THE RUGGED TERRAIN AND INCREASED VWS WILL RAPIDLY ERODE THE
SYSTEM, DISSIPATING IT AS A SIGNIFICANT CYCLONE OVER LAND BY TAU 48.
DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT, LENDING HIGH
CONFIDENCE IN THE JTWC TRACK FORECAST UP TO LANDFALL IN CHINA WHERE
TRACK VARIABILITY IS HIGH DUE TO THE FORECASTED RAPID DISSIPATION.//
NNNN

[euro6208]

[euro6208]

Raining really heavy in Kaohsiung. Pressure of 977mb and winds of 62 knots gusting to 99 knots.

If this really 10 min, then it must be really strong in 1 min.

Barely could see anything in the latest cams...

[euro6208]

Earlier, Lanyu on Orchid Island got a 130 mph gust off the southern coast of Taiwan.

[euro6208]

Winds gusting to close to 100 knots yet people still on the road driving. They tough.

[euro6208]

983.0 mb doesn't seem right because the Itbayat station was right in the eye and had no equipment failure.
I think it should be 883.0 mb. The number "7" in "57000" means "Decreasing steadily - resultant pressure lower", so the "000" after the "7" may refer to a 100.0 mb pressure decrease compares to 3 hours earlier.
And 1500z SYNOP recorded a pressure of 983 mb thus 1800z would result in a 883 mb pressure.

in addition, a 35kt (60kph) sustained wind was recorded, the minimum pressure at 18z could down to 879.5 mb (883-35/10=879.5)

WOW if your correct

Around the time of this post and Itbayat in the eye, GFS estimated a pressure of 878mb. Very close to that 879.5mb that was recorded if it was correct.

HWRF not far behind 887mb.

[euro6208]

WDPN31 PGTW 140900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 16W (MERANTI) WARNING NR
23//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUPER TYPHOON (STY) 16W (MERANTI), LOCATED APPROXIMATELY 40 NM
WEST-SOUTHWEST KAOHSIUNG, TAIWAN, HAS TRACKED NORTHWESTWARD AT 14
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY SHOWS THE SYSTEM HAS MAINTAINED A DEEP SYMMETRIC CONVECTIVE
SIGNATURE AND A 10-NM EYE. THE INITIAL POSITION IS BASED WITH HIGH
CONFIDENCE ON A COMPOSITE REFLECTIVITY RADAR LOOP FROM THE TAIWAN
CENTRAL WEATHER BUREAU. THE INITIAL INTENSITY OF 155 KNOTS IS BASED
ON A T7.5 DVORAK ESTIMATE FROM PGTW AND RJTD. UPPER LEVEL ANALYSIS
INDICATES THE SYSTEM IS JUST SOUTH OF THE RIDGE AXIS IN AN AREA OF
LIGHT EASTERLY VERTICAL WIND SHEAR (VWS) AND EXCELLENT RADIAL
OUTFLOW. SEA SURFACE TEMPERATURES AT 30 CELSIUS AND HIGH OCEAN HEAT
CONTENT ARE ALSO VERY FAVORABLE. STY 16W IS UNDER THE STEERING
INFLUENCE OF A SUBTROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
A. NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. STY 16W WILL TRACK GENERALLY WEST-NORTHWESTWARD THROUGHOUT ITS
LIFE SPAN UNDER THE STEERING INFLUENCE OF THE STR. INCREASING VWS AND
LAND INTERACTION, AS IT BRUSHES THE SOUTHERN COAST OF TAIWAN AND
APPROACHES EASTERN CHINA, WILL GRADUALLY WEAKEN THE SYSTEM. SHORTLY
BEFORE TAU 12, STY MERANTI WILL MAKE LANDFALL IN CHINA NEAR SHANTOU.
THE RUGGED TERRAIN AND INCREASED VWS WILL RAPIDLY ERODE THE SYSTEM,
DISSIPATING IT AS A SIGNIFICANT CYCLONE OVER LAND BY TAU 36. DYNAMIC
MODEL GUIDANCE REMAINS IN GOOD AGREEMENT, LENDING HIGH CONFIDENCE IN
THE JTWC TRACK FORECAST UP TO LANDFALL IN CHINA WHERE TRACK
VARIABILITY IS HIGH DUE TO LAND INTERACTION.//
NNNN

[NotoSans]

This is nowhere near 155 knots right now. Probably closer to 125 knots. Dvorak estimates are badly constrained right now and has a well-known high bias on weakening storms, and the JTWC should stop blindly following the CI numbers.

[Alyono]

probably more like 90 to 100 kts. Not sure what JTWC is doing keeping the winds as high as they are