WPAC: PHANFONE - Post-Tropical

[gatorcane]

18Z GFS bombs it out with a 936MB typhoon south of SW Japan:

[cycloneye]

00z Best Track up to 105kts. From 75kts to 105kts is a big jump but IMO they could have gone a little bit higher with what images show.

18W PHANFONE 141002 0000 19.5N 139.0E WPAC 105 944

[gatorcane]

Saved IR GIF. Impressive indeed with eye visible:

[CrazyC83]

That eye is probably less than 5 nautical miles wide. Classic pinhole eye.

[Yellow Evan]

00z Best Track up to 105kts. From 75kts to 105kts is a big jump but IMO they could have gone a little bit higher with what images show.

18W PHANFONE 141002 0000 19.5N 139.0E WPAC 105 944

105 knts seems right, based on the fact SSD and SAB broke constraints and the high FT values as well as the 5.5's across the board.

[Yellow Evan]

Take back what I just said.

"THE INITIAL INTENSITY HAS BEEN GREATLY INCREASED TO 105 KNOTS WHICH IS
BASED ON SUBJECTIVE DVORAK INTENSITY ESTIMATES THAT HAVE RAPIDLY
INCREASED TO 115 KNOTS OVER THE PAST SIX HOURS WHILE THE OBJECTIVE
INTENSITY ESTIMATES RANGE FROM 65 TO 80 KNOTS."

I don't buy their reasoning. I love ADT, but it is missing the pinhole.

[cycloneye]

Here is the whole discussion of the 0300z warning.

WDPN32 PGTW 020300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 18W (PHANFONE) WARNING NR 14//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 18W (PHANFONE), LOCATED APPROXIMATELY 343 NM SOUTH-
SOUTHWEST OF IWO TO, HAS TRACKED WEST-NORTHWESTWARD AT 14 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL (MSI) AND ENHANCED
INFRARED (EIR) SATELLITE IMAGERY REVEALS TY 19W HAS STARTED TO
RAPIDLY INTENSIFY AS A SMALL EYE FEATURE HAS DEVELOPED WHILE
CONVECTIVE BANDING HAS INCREASED IN ALL QUADRANTS. A 012218Z SSMIS
MICROWAVE IMAGE ADDITIONALLY DEPICTS A SMALL (APPROXIMATELY 25 NM)
EYEWALL FEATURE WITH MULTIPLE BROKEN CONVECTIVE BANDS IN THE OUTER
PERIPHERIES. THE INITIAL POSITION IS BASED ON THE SMALL EYE FEATURE
OBSERVED IN THE MSI AND EIR ANIMATION WITH HIGH CONFIDENCE. THE
INITIAL INTENSITY HAS BEEN GREATLY INCREASED TO 105 KNOTS WHICH IS
BASED ON SUBJECTIVE DVORAK INTENSITY ESTIMATES THAT HAVE RAPIDLY
INCREASED TO 115 KNOTS OVER THE PAST SIX HOURS WHILE THE OBJECTIVE
INTENSITY ESTIMATES RANGE FROM 65 TO 80 KNOTS. UPPER-LEVEL ANALYSIS
INDICATES THE SYSTEM IS LOCATED IN A FAVORABLE ENVIRONMENT WITH LOW
VERTICAL WIND SHEAR (VWS) AND GOOD DUAL CHANNEL OUTFLOW WHICH IS
BEING ENHANCED BY THE MID-LATITUDE WESTERLIES TO THE NORTH. TY 18W
IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYERED
SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING BULLETIN ALTHOUGH THE INTENSITY
FORECAST HAS BEEN INCREASED DUE TO ONSET OF RECENT RAPID
INTENSIFICATION EVENT.
B. TY 18W WILL CONTINUE TO TRACK TO THE NORTHWEST OVER THE NEXT
48 HOURS AS THE SYSTEM PROCEEDS ALONG THE SOUTHWESTERN PERIPHERY OF
THE STR. AN UPPER LEVEL TROUGH, WHICH IS CURRENTLY ANALYZED OVER
EASTERN CHINA, IS EXPECTED TO PROPAGATE TO THE EAST WHICH WILL
MODIFY AND BREAK THE RIDGE AXIS ALLOWING THE SYSTEM TO TRACK MORE
POLEWARD BETWEEN TAU 48 TO 72. THE SYSTEM IS EXPECTED TO REACH A
MAXIMUM INTENSITY OF 130 KNOTS BY TAU 36 AS THE FAVORABLE UPPER
LEVEL ENVIRONMENT AND OCEAN HEAT CONTENT REACH A PEAK NEAR THIS TIME
FRAME. OVERALL, NUMERIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT
THROUGH TAU 72 HAVING ONLY A 140 NM SPREAD WITH THE EXCEPTION OF
ECMWF, WHICH REMAINS THE FAR WESTERN MOST OUTLIER.
C. IN THE EXTENDED FORECAST, THE SYSTEM IS EXPECTED TO ROUND THE
RIDGE AXIS AND ACCELERATE NORTHEASTWARD, WEAKENING AS THE SYSTEM
ENCOUNTERS THE MID-LATITUDE WESTERLIES AND BEGINS EXTRATROPICAL
TRANSITION (ETT) AFTER TAU 96. MODELS CONTINUE TO DEPICT A RECURVE
SCENARIO SOUTH OF THE HONSHU, WITH THE SYSTEM COMPLETING ETT BY TAU
120 AS IT BECOMES EMBEDDED IN THE BAROCLINIC ZONE AND BECOMES A
STORM-FORCE LOW. LOW CONFIDENCE REMAINS IN THE FORECAST TRACK, WHICH
IS CLOSE TO THE MULTI-MODEL CONSENSUS AS MODELS CONTINUE DISAGREE ON
THE EXTENT OF RECURVATURE AND HOW THE STR MODIFIES IN RESPONSE TO
THE AFOREMENTIONED TROUGH.//

[Alyono]

should always go 1 full T number above the Dvorak on a pinhole eye

[euro6208]

PINHOLE EYE!

[euro6208]

[euro6208]

00z Best Track up to 105kts. From 75kts to 105kts is a big jump but IMO they could have gone a little bit higher with what images show.

18W PHANFONE 141002 0000 19.5N 139.0E WPAC 105 944

Agree looks better than 105 knots.

Classic destructive core...I wouldn't be surprised if this had at least 150 knots and a cp below 900...

[TropicalAnalystwx13]

The eye is starting to wobble quite a bit (see also: trochoidal oscillations). 105kts is probably conservative.

[euro6208]

[Yellow Evan]

should always go 1 full T number above the Dvorak on a pinhole eye

That'd support 125-140 knts. Unless you mean ADT.

[euro6208]

Looks like ADT missed the small center resulting in only 3.8 and ON weakening flag...

Dvorak of course always have trouble with pinhole eyes and powerful typhoons...

[Yellow Evan]

Looks like ADT missed the small center resulting in only 3.8 and ON weakening flag...

Dvorak of course always have trouble with pinhole eyes and powerful typhoons...

Which ADT version? 8.1.4, 8.2.1, or 8.1.5.

[euro6208]

Looks like ADT missed the small center resulting in only 3.8 and ON weakening flag...

Dvorak of course always have trouble with pinhole eyes and powerful typhoons...

Which ADT version? 8.1.4, 8.2.1, or 8.1.5.

8.2.1

[Yellow Evan]

8.1.5 got it right

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.5
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 02 OCT 2014 Time : 030000 UTC
Lat : 19:33:06 N Lon : 138:13:53 E


CI# /Pressure/ Vmax
4.2 / 974.6mb/ 69.8kt


Final T# Adj T# Raw T#
4.2 4.9 6.3

Estimated radius of max. wind based on IR :N/A km

Center Temp : -36.0C Cloud Region Temp : -78.1C

Scene Type : EYE

Positioning Method : SPIRAL ANALYSIS

Ocean Basin : WEST PACIFIC
Dvorak CI > MSLP Conversion Used : PACIFIC

Tno/CI Rules : Constraint Limits : 1.0T/6hr
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 108km
- Environmental MSLP : 1003mb

Satellite Name : MTSAT2
Satellite Viewing Angle : 24.1 degrees

[Yellow Evan]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.5
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 02 OCT 2014 Time : 033000 UTC
Lat : 19:36:29 N Lon : 138:08:45 E


CI# /Pressure/ Vmax
4.2 / 974.6mb/ 69.8kt


Final T# Adj T# Raw T#
4.2 4.8 6.4

Estimated radius of max. wind based on IR :N/A km

Center Temp : -23.2C Cloud Region Temp : -77.7C

Scene Type : EYE

Positioning Method : SPIRAL ANALYSIS

Ocean Basin : WEST PACIFIC
Dvorak CI > MSLP Conversion Used : PACIFIC

Tno/CI Rules : Constraint Limits : 1.0T/6hr
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 108km
- Environmental MSLP : 1003mb

Satellite Name : MTSAT2
Satellite Viewing Angle : 24.2 degrees

[euro6208]

There goes our 145-155 knots Category 5. Dvorak likely underestimating the strength.

Anyone remember Wilma?