WPAC: 04W - Post-Tropical

[wxman57]

JTWC says 35 kts, JMA says TD. JMA is the official agency of the basin, so it remains a TD. ASCAT pass from 1139Z indicated 30 kts. Band 7 of HImawari 8 clearly shows the LLC west of the convection. Looks like a struggling TD, to me. Don't know that it will make it to TS strength. No big threat to anyone.

[euro6208]

Now upgraded to the 4th TS of the season...

WDPN31 PGTW 122100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 04W (FOUR)
WARNING NR 04//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 04W (FOUR), LOCATED APPROXIMATELY 62 NM EAST OF
AGRIHAN, HAS TRACKED WESTWARD AT 06 KNOTS OVER THE PAST SIX
HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A
FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) LOCATED TO THE
WEST OF AN AREA OF PERSISTENT DEEP CONVECTION. THE INITIAL POSITION
IS PLACED WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLCC IN THE EIR
IMAGERY AND A 121752Z SSMIS 37GHZ MICROWAVE IMAGE THAT SHOWS
CONVECTIVE BANDING WRAPPING INTO THE CENTER. THE INTENSITY OF 35
KNOTS IS BASED ON AN EARLIER ASCAT PASS SHOWING AN AREA OF 35 KNOT
WINDS AND IS SUPPORTED BY AGENCY DVORAK CURRENT INTENSITY ESTIMATES
OF T2.0 (30 KTS) FROM BOTH PGTW AND KNES. THE INITIAL INTENSITY IS
ALSO SUPPORTED BY A RECENT SATCON ESTIMATE OF 34 KNOTS. UPPER LEVEL
ANALYSIS REVELS THE SYSTEM HAS DIVERGENCE ALOFT WITH POLEWARD
OUTFLOW. ENVIRONMENTAL ANALYSIS INDICATES THAT THE SYSTEM IS IN AN
AREA OF UNFAVORABLE VERTICAL WIND SHEAR BETWEEN 20 AND
30 KNOTS WHICH IS SHEARING THE CONVECTION TO THE EAST OF THE LLCC.
THE SYSTEM IS ALSO TRACKING THROUGH WARM (28-29 CELSIUS) SEA SURFACE
TEMPERATURES. TS 04W IS TRACKING WESTWARD AROUND THE SOUTHERN EXTENT
OF A SUBTROPICAL RIDGE (STR) LOCATED TO THE EAST.
3. FORECAST REASONING.
A. THERE IS NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TS 04W IS FORECAST TO TRACK NORTHWESTWARD AROUND THE STR
THROUGH TAU 24. AFTER TAU 24, THE SYSTEM WILL CROSS THE RIDGE AXIS
AND RECURVE TO THE NORTHEAST. MARGINALLY FAVORABLE ENVIRONMENTAL
CONDITIONS INCLUDING MODERATE POLEWARD OUTFLOW AND WARM SEA SURFACE
TEMPERATURES WILL ALLOW FOR TS 04W TO MAINTAIN AN INTENSITY OF 35
KNOTS THROUGH TAU 24. BEYOND TAU 24, STRONG VERTICAL WIND SHEAR
COMBINED WITH COOLER SEA SURFACE TEMPERATURES WILL CAUSE TS 04W TO
EVENTUALLY DISSIPATE BY TAU 48. AN APPROACHING SHORT-WAVE TROUGH
MOVING IN FROM THE WEST WILL BEGIN TO INTERACT WITH THE SYSTEM AFTAER
TAU 36, ALSO CONTRIBUTING TO DISSIPATION. DYNAMIC MODEL GUIDANCE IS
GENERALLY IN GOOD AGREEMENT, LENDING OVERALL HIGH CONFIDENCE IN THE
JTWC FORECAST TRACK.//
NNNN

[euro6208]

926
WTPQ31 PGUM 122134
TCPPQ1

BULLETIN
TROPICAL STORM 04W Advisory Number 4
National Weather Service Tiyan GU WP042018
800 AM ChST Sun May 13 2018

...TROPICAL STORM 04W SLOWLY MOVING WEST...

WATCHES AND WARNINGS
--------------------
None.

SUMMARY OF 700 AM CHST...2100 UTC...INFORMATION
----------------------------------------------
Location...19.0N 146.4E

About 50 miles east-northeast of Agrihan
About 75 miles north-northeast of Pagan
About 95 miles north-northeast of Alamagan
About 270 miles north of Saipan
About 400 miles north-northeast of Guam

Maximum sustained winds...40 mph
Present movement...west...270 degrees at 7 mph

DISCUSSION AND OUTLOOK
----------------------
At 700 AM CHST...2100 UTC...the center of Tropical Storm 04W was
located near latitude 19.0 degrees north and longitude 146.4 degrees
east....moving west at about 7 mph. Tropical Storm 04W is expected
to turn to the northwest later this morning, then northward by
Monday morning. The current track will take TS 04W about 30 miles
north of Agrihan later this morning.

Maximum sustained winds remain at 40 mph, making 04W a minimal
tropical storm. 04W is expected to maintain this intensity today,
then weaken back into a tropical depression Monday.

Tropical Storm force winds extend outward up to 60 miles north of
the center and 0 miles south of the center. As currently forecast,
damaging winds are not expected at Agrihan, Pagan or Alamagan as 04W
passes to the north. However, residents of these islands should keep
up to date on the latest advisories and statements on Tropical
Storm 04W.

NEXT ADVISORY
-------------
The next scheduled advisory will be issued by the National Weather
Service at 200 PM this afternoon.

$$

Kleeschulte

[euro6208]

JTWC at 2.0 and SSD at 3.0 now.


TPPN11 PGTW 122104

A. TROPICAL STORM 04W (NNE OF GUAM)

B. 12/2040Z

C. 19.15N

D. 146.76E

E. THREE/HMWRI8

F. T2.0/2.0/D0.5/24HRS STT: S0.0/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: 19A/PBO XPSD LLCC/ANMTN. CNVCTN SHEARED 30NM FROM
LLCC YIELDS A DT OF 3.5. MET/PT 2.0. DBO PT.

I. ADDITIONAL POSITIONS:
12/1544Z 18.88N 147.13E ATMS


DAVIS

TXPQ23 KNES 122110
TCSWNP

A. 04W (NONAME)

B. 12/2030Z

C. 19.2N

D. 146.7E

E. THREE/HIMAWARI-8

F. T3.0/3.0/D1.5/24HRS

G. IR/EIR/VIS

H. REMARKS...SHEARED CENTER OF CIRCULATION WAS LOCATED LESS THEN 1/2
DEGREE LAT FROM OVERCAST RESULTING IN DT=3.0. MET=2.0 AND PT=2.0. FT IS
BASED ON DT.

I. ADDL POSITIONS

NIL


...BOLL

[euro6208]

JTWC says 35 kts, JMA says TD. JMA is the official agency of the basin, so it remains a TD. ASCAT pass from 1139Z indicated 30 kts. Band 7 of HImawari 8 clearly shows the LLC west of the convection. Looks like a struggling TD, to me. Don't know that it will make it to TS strength. No big threat to anyone.

That matches pretty well...30 knots 10 minutes= 35 knots 1 min. Classic look of a sheared TS.

[NotoSans]

I'd say this is a marginal TS.

[euro6208]

[euro6208]

CURRENT ESTIMATE
Date (mmddhhmm): 05122126
SATCON: MSLP = 1005 hPa MSW = 38 knots
SATCON Member Consensus: 37.0 knots
Pressure -> Wind Using SATCON MSLP: 41 knots
Distance to Outer Closed Isobar Used is 155 nm
Eye Size Correction Used is 0 knots Source: NA

Member Estimates

ADT: 1010 hPa 28 knots Scene: CDO Date: MAY122040
CIMSS AMSU: 1002 hPa 34 knots Bias Corr: 0 (MW) Date: 05121756
ATMS: 1007.2 hPa 33.8 knots Date: 05121543
SSMIS: 1000.0 hPa 47.0 knots Date: 05122126
CIRA ATMS: hPa knots Date:

[euro6208]

WDPN31 PGTW 130300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 04W (FOUR)
WARNING NR 05//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 04W (FOUR), LOCATED APPROXIMATELY 54 NM NORTHEAST
OF AGRIHAN, HAS TRACKED NORTHWESTWARD AT 06 KNOTS OVER THE PAST SIX
HOURS. ANIMATED ENHANCED MULTI-SPECTRAL SATELLITE IMAGERY (MSI)
SHOWS A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH
PERSISTENT DEEP CONVECTION SHEARED 15 NM TO THE EAST. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLCC IN
THE MSI LOOP AND A 122328Z MMHS 89GHZ MICROWAVE IMAGE THAT SHOWS
WEAK CONVECTIVE BANDING WRAPPING INTO THE CENTER. THE INITIAL
INTENSITY OF 35 IS ON THE UPPER END OF MULTI-AGENCY DVORAK CURRENT
INTENSITY ESTIMATES RANGING FROM T2.0 TO T3.0 (30-35 KTS) FROM PGTW
AND KNES RESPECTIVELY. THE INITIAL INTENSITY IS ALSO SUPPORTED BY A
RECENT SATCON ESTIMATE OF 36 KNOTS. UPPER LEVEL ANALYSIS REVEALS THE
SYSTEM HAS GOOD POLEWARD OUTFLOW. ENVIRONMENTAL ANALYSIS INDICATES
THAT THE SYSTEM IS IN AN AREA OF UNFAVORABLE VERTICAL WIND SHEAR
BETWEEN 30 AND 40 KNOTS WHICH IS CAUSING THE CONVECTION TO SHEAR TO
THE EAST OF THE LLCC. THE SYSTEM IS ALSO TRACKING THROUGH WARM (27-
28 CELSIUS) SEA SURFACE TEMPERATURES. TS 04W IS CURRENTLY TRACKING
NORTHWESTWARD AROUND THE SOUTHERN EXTENT OF A SUBTROPICAL RIDGE
(STR) LOCATED TO THE EAST.
3. FORECAST REASONING.
A. THERE IS NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TS 04W IS FORECAST TO TRACK NORTHWESTWARD AROUND THE STR,
CROSSING THE RIDGE AXIS AROUND TAU 24. AFTER CROSSING THE AXIS, THE
SYSTEM WILL RECURVE AND TRACK TO THE NORTHEAST. MARGINALLY FAVORABLE
ENVIRONMENTAL CONDITIONS WITH MODERATE POLEWARD OUTFLOW AND WARM SEA
SURFACE TEMPERATURES OFFSETTING HIGH VERTICAL WIND SHEAR WILL ALLOW
FOR TS 04W TO MAINTAIN AN INTENSITY OF 35 KNOTS THROUGH TAU 12.
BEYOND TAU 12, THE SYSTEM WILL BEGIN A GRADUAL DISSIPATION AS
VERTICAL WIND SHEAR INCREASES FOLLOWED BY COOLING SEA SURFACE
TEMPERATURES. AN APPROACHING SHORT-WAVE TROUGH MOVING IN FROM THE
WEST WILL BEGIN TO INTERACT WITH THE SYSTEM AFTER TAU 24, LEADING TO
COMPLETE DISSIPATION BY TAU 48. DYNAMIC MODEL GUIDANCE REMAINS IN
GOOD AGREEMENT, LENDING OVERALL HIGH CONFIDENCE IN THE JTWC FORECAST
TRACK.//
NNNN

[euro6208]

JMA only has this...

TROPICAL DEPRESSION 1010 HPA
AT 19.1N 146.6E MARIANAS MOVING WESTNORTHWEST SLOWLY.
POSITION FAIR.
MAX WINDS 30 KNOTS NEAR CENTER.
WARNING.

[euro6208]

WTPN31 PGTW 132100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TROPICAL DEPRESSION 04W (FOUR) WARNING NR 008
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
131800Z --- NEAR 20.6N 144.4E
MOVEMENT PAST SIX HOURS - 300 DEGREES AT 06 KTS
POSITION ACCURATE TO WITHIN 030 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 20.6N 144.4E
---
FORECASTS:
12 HRS, VALID AT:
140600Z --- 22.1N 144.3E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 24 HR POSIT: 035 DEG/ 10 KTS
---
24 HRS, VALID AT:
141800Z --- 23.8N 145.5E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
132100Z POSITION NEAR 21.0N 144.4E.
TROPICAL DEPRESSION 04W (FOUR), LOCATED APPROXIMATELY 131 NM
NORTHWEST OF AGRIHAN, HAS TRACKED WEST-NORTHWESTWARD AT 06 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY DEPICTS AN ELONGATED, FULLY EXPOSED LOW LEVEL CIRCULATION
CENTER (LLCC) WITH DEEP CONVECTION DISPLACED TO THE EAST. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EXPOSED
LLCC IN THE EIR IMAGERY AND SUPPORTED BY A 131701Z SSMI 85GHZ
MICROWAVE IMAGE. THE INITIAL INTENSITY OF 25 KNOTS IS BASED ON A
PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T1.5 (25 KNOTS).
ENVIRONMENTAL ANALYSIS SHOWS THAT THE SYSTEM STILL HAS UPPER LEVEL
OUTFLOW AND IS TRACKING THROUGH 27 DEGREES CELSIUS SEA SURFACE
TEMPERATURES THAT IS OFFSET BY VERY STRONG (30-40 KNOTS) VERTICAL
WIND SHEAR. THE SYSTEM IS CURRENTLY TRACKING AROUND THE WESTERN
EXTENT OF A SUBTROPICAL RIDGE LOCATED TO THE EAST. BY TAU 12, THE
SYSTEM WILL HAVE CROSSED THE RIDGE AXIS AND WILL BE RECURVING TO THE
NORTHEAST. AN APPROACHING SHORTWAVE TROUGH WILL BRING EVEN STRONGER
VERTICAL WIND SHEAR AND CONTRIBUTE TO THE COMPLETE DISSIPATION OF
THE SYSTEM BY TAU 24. DYNAMIC MODEL GUIDANCE IS IN OVERALL GOOD
AGREEMENT LENDING OVERALL HIGH CONFIDENCE IN THE JTWC TRACK FORECAST.
THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WRNCEN
PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF
REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 131800Z IS 10
FEET.//
NNNN

[euro6208]

At the end. Only a mere 0.4 in ACE for this storm.

[NotoSans]

JMA only has this...

TROPICAL DEPRESSION 1010 HPA
AT 19.1N 146.6E MARIANAS MOVING WESTNORTHWEST SLOWLY.
POSITION FAIR.
MAX WINDS 30 KNOTS NEAR CENTER.
WARNING.

JMA doesn't issue advisories on tropical depressions unless they are expected to become a tropical storm in the next 24 hours.