WPAC: HALOLA - Post-Tropical

[euro6208]

Approaching the Marianas and Peak

[cycloneye]

WDPN32 PGTW 141500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 01C (HALOLA) WARNING
NR 18//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 01C (HALOLA), LOCATED APPROXIMATELY 413 NM EAST-
SOUTHEAST OF WAKE ISLAND, HAS TRACKED NORTHWESTWARD AT 14 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY SHOWS INCREASED CENTRAL CONVECTION BEING ELONGATED TO THE
NORTHEAST DUE TO PERSISTENT MODERATE (15-20 KNOT) SOUTHWESTERLY
VERTICAL WIND SHEAR (VWS). A 140937Z AMSU-B MICROWAVE IMAGE
ILLUSTRATES A LACK OF DEEP CONVECTION OUTSIDE OF THE CENTRAL CORE
STRUCTURE. THE CURRENT POSITION IS BASED ON THE EIR LOOP AND THE
MICROWAVE IMAGE WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS HELD
AT 85 KNOTS BASED ON AN ASSESSMENT OF AGENCY CURRENT INTENSITY
ESTIMATES. UPPER LEVEL ANALYSIS REVEALS GOOD DIFFLUENT OUTFLOW,
AIDED BY A WEAKENING TUTT CELL TO THE NORTHWEST. TY HALOLA IS
TRACKING ALONG THE SOUTHERN PERIPHERY OF A SUB-TROPICAL RIDGE (STR)
TO THE NORTH.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TY 01C WILL CONTINUE TO TRACK TO THE NORTHWEST UNDER THE
STEERING INFLUENCE OF THE STR. UPPER LEVEL CONDITIONS WILL BECOME
MORE VARIABLE AS THE TUTT CELL ASSISTING WITH OUTFLOW FULLY
DISSIPATES AND AN UPPER LEVEL RIDGE BUILDING TO THE NORTHWEST
SUPPRESSES THE POLEWARD OUTFLOW. THE VARIABLE UPPER LEVEL
ENVIRONMENT WILL LEAD TO A MODEST INTENSIFICATION RATE. THE
SYSTEM WILL BEND TO A MORE WESTWARD TRACK AFTER TAU 36 AS THE
STEERING STR FLATTENS AND PRESSES DOWN ON THE CYCLONE.
C. BEYOND TAU 72, TY HALOLA WILL BEGIN TRACKING NORTHWESTWARD
AGAIN AS THE SYSTEM MOVES DOWNSTREAM FROM THE STEERING STR AXIS.
EXPECT THE RATE OF INTENSIFICATION TO INCREASE AS TY 01C REGAINS A
POLEWARD OUTFLOW CHANNEL AND SEA SURFACE TEMPERATURES REMAIN
FAVORABLE. AVAILABLE MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT WITH
THE MULTI-MODEL CONSENSUS REMAINING UNCHANGED OVER THE PAST 4
CYCLES, LEADING TO HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.//
NNNN

[cycloneye]

http://i.imgur.com/qbUhvrO.gif

[weathernerdguy]

Is it dying off now?

[cycloneye]

[wxman57]

Is it dying off now?

A microwave pass overnight indicates no eye and a center displaced SW of the convection:

[cycloneye]

WDPN32 PGTW 150900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 01C (HALOLA) WARNING
NR 21//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 01C (HALOLA), LOCATED APPROXIMATELY 222 NM EAST-
SOUTHEAST OF WAKE ISLAND, HAS TRACKED WEST-NORTHWESTWARD AT 13 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
SHOWS A DISORGANIZED CONVECTIVE SIGNATURE BEING ELONGATED TO THE
NORTHEAST DUE TO MODERATE (15-20 KNOT) SOUTHWESTERLY VERTICAL WIND
SHEAR (VWS). A 150331Z GPM 89GHZ MICROWAVE IMAGE FURTHER ILLUSTRATES
THE WEAK AND DISORGANIZED NATURE OF THE CYCLONE. HOWEVER, TIGHT
SHALLOW CURVED BANDING REMAINS EVIDENT ALONG THE WESTERN QUADRANT
AND SUPPORTS THE CURRENT POSITION WITH GOOD CONFIDENCE. THE INITIAL
INTENSITY HAS BEEN LOWERED SLIGHTLY TO 80 KNOTS BASED ON THE WEAK
STRUCTURE OF THE SYSTEM AND AN ASSESSMENT OF REDUCED DVORAK
INTENSITY ESTIMATES FROM ALL AGENCIES. TY HALOLA IS LOCATED IN AN
AREA OF GOOD POLEWARD OUTFLOW AND FAVORABLE SEA SURFACE
TEMPERATURES; HOWEVER, THE MODERATE VWS IS PREVENTING CONSOLIDATION
AND INTENSIFICATION. TY HALOLA IS TRACKING ALONG THE SOUTHERN
PERIPHERY OF A SUB-TROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TY 01C WILL REMAIN ON A WEST-NORTHWESTWARD TRAJECTORY AS IT
TRACKS ALONG THE SOUTHERN PERIPHERY OF THE STEERING STR.
ENVIRONMENTAL CONDITIONS WILL REMAIN MARGINAL OVER THE NEXT 36 TO 48
HOURS LEADING TO MINIMAL INTENSIFICATION. THERE IS A POSSIBILITY
THAT THE SYSTEM CONTINUES TO STRUGGLE TO CONSOLIDATE AND WEAKENS
SLIGHTLY OVER THIS TIME PERIOD. BEYOND TAU 48, ENVIRONMENTAL
CONDITIONS WILL IMPROVE AS THE CYCLONE GAINS A POLEWARD OUTFLOW
CHANNEL AND BEGINS A GRADUAL INTENSIFICATION.
C. BEYOND TAU 72, TY HALOLA WILL BEGIN TO TURN TO THE NORTHWEST
AS IT STARTS TO ROUND THE SOUTHWESTERN PERIPHERY OF THE STEERING
STR. EXPECT CONTINUED INTENSIFICATION AS THE CYCLONE TAPS FURTHER
INTO THE POLEWARD OUTFLOW. SEA SURFACE TEMPERATURES WILL REMAIN
FAVORABLE. AVAILABLE MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT
LENDING TO HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.//
NNNN

[wxman57]

I'd say visible and microwave satellite imagery don't support anything near 80 kts. Maybe 40 kts. Dvorak estimates are way off because they're assuming the center is about 100 miles too far north.

[wxman57]

Here's a new microwave image. Halola isn't even close to being a typhoon. One could argue it's barely a TS.

[Dave C]

that sw shear really spanking it. Will be interesting to see if it rebounds later.

[wxman57]

Good Rapidscat pass (from the instrument on the space shuttle) a couple hours ago. Shows a broad, elongated center (not well-defined). Some non-contaminated winds to 35 kts. No way it's a 75kt typhoon and the center is not located at 18.3N as per the latest JTWC advisory. The circulation remains displaced to the SW of the convection, not in the middle of the convection.

[cycloneye]

[euro6208]

Surprised the NWS didn't issue any typhoon warnings for Wake Island...Anyone know why?

I think there are a few people in that island...

[euro6208]

What a long life

GFS seeing more than a week of longevity as a tropical cyclone then becoming a powerful extratropical cyclone in the north pacific...

It bottoms it out at 939 mb before recurving...

[wxman57]

Halola still appears to barely have a circulation today. A recent microwave pass (and visible satellite imagery) puts the center well SSW of any convection (and JTWC's position - the yellow "X").



A 10Z ASCAT pass indicated an elongated trof for a circulation center and no TS winds. Max winds on the pass were 30kts.

[dexterlabio]

Is this a similar case of Chan-hom last week when it cracked open then recovered to becoming a Cat 4 later on? Or is this weakening trend set in stone?

[cycloneye]

WDPN32 PGTW 162100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01C (HALOLA) WARNING NR
27//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 01C (HALOLA), LOCATED APPROXIMATELY 950 NM
EAST-NORTHEAST OF SAIPAN, CNMI, HAS TRACKED WESTWARD AT 19 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED IR IMAGERY SHOWS THE
SYSTEM CONTINUES TO BE INUNDATED BY HIGH VWS, DISPLACING THE
CONVECTION EASTWARD AND FULLY EXPOSING A RAGGED LLCC. ADDITIONALLY
THE IR LOOP SHOWS A COMPACT OUTFLOW THAT IS BEING SUPPRESSED BY A
TUTT TO THE NORTHEAST. THE INITIAL POSITION IS BASED ON THE EXPOSED
LLCC WITH FAIR CONFIDENCE. THE INITIAL INTENSITY OF 35 KNOTS IS
BASED ON AN OVERALL ASSESSMENT OF DVORAK ESTIMATES FROM PGTW, KNES,
AND RJTD. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS SOUTH OF THE
RIDGE AXIS IN AN AREA OF MODERATE (15-20 KNOT) VWS. THE SYSTEM IS
TRACKING ALONG THE SOUTHERN PERIPHERY OF THE STR.
3. FORECAST REASONING.
A. THE FORECAST INTENSITIES HAVE BEEN SIGNIFICANTLY REDUCED IN
VIEW OF MORE RECENT DATA, OTHERWISE, THE TRACK FORECAST CONFORMS WITH
THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING
MESSAGE.
B. TS 01C WILL CONTINUE TRACKING GENERALLY WESTWARD TO
WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR. THE VWS
IS EXPECTED TO GRADUALLY RELAX ALLOWING FOR THE SYSTEM TO SLOWLY
INTENSIFY, REACHING 70 KNOTS BY TAU 72.
C. BEYOND TAU 72, TS HALOLA WILL BEGIN TO TRACK T NORTHWESTWARD
AS THE STR WEAKENS. THE SYSTEM WILL PEAK AT 80 KNOTS BY TAU 96;
AFTERWARDS, COLDER SSTS AND INCREASING VWS WILL BEGIN TO WEAKEN TS
01C TOWARDS THE END OF THE FORECAST. NUMERIC MODEL GUIDANCE IS IN
FAIRLY TIGHT AGREEMENT LENDING HIGH CONFIDENCE IN THE JTWC FORECAST
TRACK. HOWEVER, THERE IS LOW CONFIDENCE IN THE INTENSITY FORECAST DUE
TO UNCERTAINTY IN THE VWS AND OUTFLOW.//
NNNN

[wxman57]

An ASCAT pass from around 1030Z indicated a weak LLC and 35kt winds. Since then it appears that Halola's circulation has deteriorated. I'm not sure it has enough of an LLC to be classified as a tropical cyclone at this point. I see JTWC has relocated the center closer to where microwave and visible satellite imagery now indicates it to be, and they've dropped the intensity to 35kts. That may be a little generous, but not bad. The question is whether it will survive and regenerate its circulation. I think it will regain typhoon intensity.

I notice that the EC deterministic and ensembles now turn it northward well east of Japan, as the GFS had been indicating.

[cycloneye]

They say is going to be a Typhoon again.



WDPN32 PGTW 170300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01C (HALOLA) WARNING NR
28//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 01C (HALOLA), LOCATED APPROXIMATELY 1160 NM EAST-
SOUTHEAST OF IWO JIMA, HAS TRACKED WESTWARD AT 10 KNOTS OVER THE
PAST SIX HOURS. RECENT ANIMATED MSI DEPICTS FLARING DEEP CONVECTION
OBSCURING THE LLCC. THE CURRENT POSITION IS BASED ON THE MSI AND
SATELLITE FIXES FROM PGTW AND RJTD WITH GOOD CONFIDENCE. THE INITIAL
INTENSITY OF 35 KNOTS IS BASED ON AN OVERALL ASSESSMENT OF DVORAK
INTENSITY ESTIMATES FROM ALL REPORTING AGENCIES. UPPER-LEVEL
ANALYSIS INDICATES THE SYSTEM IS SOUTH OF THE RIDGE AXIS IN AN AREA
OF MODERATE (15 TO 20 KNOT) VWS. THE SYSTEM IS TRACKING ALONG THE
SOUTHERN PERIPHERY OF THE STR.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TS 01C WILL CONTINUE TRACKING GENERALLY WESTWARD TO
WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR. THE VWS
IS EXPECTED TO GRADUALLY RELAX ALLOWING FOR THE SYSTEM TO SLOWLY
INTENSIFY, REACHING 70 KNOTS BY TAU 72.
C. BEYOND TAU 72, TS HALOLA WILL BEGIN TO TRACK NORTHWESTWARD
AS THE STR WEAKENS. THE SYSTEM WILL PEAK AT 80 KNOTS BY TAU 96.
AFTERWARDS, COLDER SSTS AND INCREASING VWS WILL BEGIN TO WEAKEN TS
01C TOWARDS THE END OF THE FORECAST. NUMERIC MODEL GUIDANCE IS IN
FAIRLY TIGHT AGREEMENT LENDING HIGH CONFIDENCE IN THE JTWC TRACK
FOREAST.//
NNNN

[wxman57]

Here's a good ASCAT pass this morning. Halola is more of an inverted trof with 30kt max winds. Circulation is very elongated and not well-defined. It's a borderline TD (bordering with remnant low, not TS).

All 50 EC ensemble members dissipate it within 2 days.