WPAC: NEOGURI - Post-Tropical

[euro6208]

WDPN31 PGTW 031500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 08W (EIGHT)
WARNING NR 03//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION (TD) 08W (EIGHT), LOCATED APPROXIMATELY 184 NM
SOUTH-SOUTHWEST OF ANDERSEN AFB, HAS TRACKED NORTHWESTWARD AT 13
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS A SLOWLY-CONSOLIDATING LOW-LEVEL CIRCULATION CENTER
(LLCC) WITH IMPROVED CONVECTIVE BANDING OVER THE SOUTHERN SEMI-
CIRCLE. HOWEVER, A 031151Z METOP-B IMAGE DEPICTS AN ELONGATED LLCC
WITH AN ILL-DEFINED CENTER AND CHAOTIC STRUCTURE, THEREFORE, THERE
IS A MODERATE AMOUNT OF UNCERTAINTY IN THE EXACT INITIAL POSITION
AND TRACK SPEED. ANIMATED WATER VAPOR IMAGERY AND CLOUD DRIFT WINDS
INDICATE GOOD EQUATORWARD OUTFLOW, HOWEVER, POLEWARD OUTFLOW IS
LIMITED DUE TO CONVERGENT FLOW ASSOCIATED WITH THE UPPER-LEVEL
SUBTROPICAL RIDGE POSITIONED TO THE NORTH. THE INITIAL INTENSITY IS
ASSESSED AT 30 KNOTS BASED ON RECENT ASCAT DATA AND T2.0 (30 KNOTS)
DVORAK INTENSITY ESTIMATES FROM KNES AND PGTW. TD 08W IS CURRENTLY
TRACKING WEST-NORTHWESTWARD ALONG THE LOW- TO MID-LEVEL SUBTROPICAL
RIDGE (STR) ENTRENCHED NORTH OF THE SYSTEM.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TD 08W IS FORECAST TO TRACK WEST-NORTHWESTWARD TO
NORTHWESTWARD THROUGH TAU 72 ALONG THE SOUTHERN PERIPHERY OF THE
STR. THE 03/00Z 500 MB ANALYSIS DEPICTS A STRONG STR ORIENTED EAST-
WEST, EXTENDING WESTWARD TO NEAR TAIWAN. DYNAMIC GUIDANCE IS
CURRENTLY IN TIGHT AGREEMENT WITH A 140 NM SPREAD IN SOLUTIONS AT
TAU 72. HOWEVER, GUIDANCE HAS BEEN FAIRLY ERRATIC AND, IN GENERAL,
IS TRENDING FURTHER WEST OVER THE PAST TWELVE HOURS. DUE TO THE LACK
OF A POLEWARD OUTFLOW MECHANISM, TD 08W IS FORECAST TO INTENSIFY
SLOWLY THROUGH TAU 36 THEN AT A GREATER RATE OF INTENSIFICATION
THROUGH TAU 72 AS POLEWARD OUTFLOW IMPROVES AND THE SYSTEM TRACKS
OVER A REGION OF HIGH OCEAN HEAT CONTENT VALUES.
C. IN THE EXTENDED TAUS, TD 08W IS EXPECTED TO TRACK POLEWARD
ALONG THE WESTERN PERIPHERY OF THE STR, TOWARD A BREAK IN THE STR
CREATED BY AN APPROACHING MIDLATITUDE SHORTWAVE TROUGH. WITH THE
EXCEPTION OF GFDN WHICH IS SLOWER AND FURTHER WEST, THE DYNAMIC
GUIDANCE IS IN GOOD (IMPROVED) AGREEMENT. TD 08W IS EXPECTED TO
INTENSIFY TO A PEAK INTENSITY OF 105 KNOTS AT TAU 96 DUE
TO IMPROVED POLEWARD OUTFLOW. OVERALL, THERE IS LOW CONFIDENCE IN
THE FORECAST TRACK DUE TO UNCERTAINTY IN THE INITIAL POSITION AND
TIMING OF THE RECURVE.//
NNNN

[euro6208]

TPPN10 PGTW 031516

A. TROPICAL DEPRESSION 08W (SW OF GUAM)

B. 03/1432Z

C. 10.8N

D. 143.5E

E. FIVE/MTSAT

F. T2.5/2.5/D1.5/24HRS STT: D0.5/03HRS

G. IR/EIR

H. REMARKS: 38A/PBO SBC/ANMTN. CNVCTN WRAP OF .40 ON LOG10
SPIRAL YIELDS A DT OF 2.5. PT AND MET AGREE. DBO DT.

I. ADDITIONAL POSITIONS:
03/0935Z 11.1N 144.7E SSMS
03/1151Z 10.9N 143.9E MMHS


UEHARA


TXPQ27 KNES 031518
TCSWNP

A. 08W (NONAME)

B. 03/1432Z

C. 10.5N

D. 144.3E

E. FIVE/MTSAT

F. T2.5/2.5/D1.5/24HRS

G. IR/EIR/SWIR/TMI/AMSU

H. REMARKS...08W REMAINS SLIGHTLY ELONGATED E-W BUT THERE IS GOOD
CONVECTION ROLLING UP THE EASTERN SIDE OF THE CIRCULATION THAT ALLOWS FOR
.4 BANDING FOR A DT OF 2.5. MET IS 2.0. PT IS 2.5. FT IS 2.5 BASED ON DT.

I. ADDL POSITIONS

03/0900Z 10.1N 145.5E TMI
03/1151Z 10.5N 144.7E AMSU


...GALLINA


PGTW and KNES reporting 2.5. Could see this get upgraded in a few hours..

[euro6208]

Latest radar...

It's been raining very heavy and winds are picking up. Easily gust in the 40's and 50's and the worst is yet to come...

[euro6208]

000
WTPQ31 PGUM 031511
TCPPQ1

TROPICAL DEPRESSION 08W (EIGHT) ADVISORY NUMBER 3
NATIONAL WEATHER SERVICE TIYAN GU WP082014
200 AM CHST FRI JUL 4 2014

...TD 08W PASSING SOUTH OF GUAM INTO THE PHILIPPINE SEA...

WATCHES AND WARNINGS
--------------------
NONE.

SUMMARY OF 100 AM CHST...1500 UTC...INFORMATION
-----------------------------------------------

LOCATION...11.1N 143.5E

ABOUT 185 MILES SOUTH-SOUTHWEST OF GUAM
ABOUT 235 MILES SOUTH-SOUTHWEST OF ROTA
ABOUT 305 MILES SOUTH-SOUTHWEST OF TINIAN
ABOUT 315 MILES SOUTH-SOUTHWEST OF SAIPAN
ABOUT 385 MILES EAST-NORTHEAST OF YAP AND
ABOUT 675 MILES EAST-NORTHEAST OF KOROR.

MAXIMUM SUSTAINED WINDS...35 MPH
PRESENT MOVEMENT...NORTHWEST AT 15 MPH

DISCUSSION AND OUTLOOK
----------------------

AT 100 AM CHST...1500 UTC...THE CENTER OF TROPICAL DEPRESSION (08W)
WAS LOCATED BY SATELLITE NEAR LATITUDE 11.1 DEGREES NORTH AND
LONGITUDE 143.5 DEGREES EAST.

TROPICAL DEPRESSION 08W IS MOVING NORTHWEST AT 15 MPH. TD 08W IS
EXPECTED TO CONTINUE MOVING IN THIS GENERAL DIRECTION WITH A
GRADUAL DECREASE IN FORWARD SPEED DURING THE NEXT 24 HOURS.

MAXIMUM SUSTAINED WINDS REMAIN NEAR 35 MPH. TROPICAL DEPRESSION 08W
IS STILL EXPECTED TO INTENSIFY THROUGH SATURDAY...AND WILL LIKELY
BECOME A TROPICAL STORM LATER TODAY.

NEXT ADVISORY
-------------

THE NEXT SCHEDULED ADVISORY FOR TROPICAL DEPRESSION 08W WILL BE
ISSUED BY THE NATIONAL WEATHER SERVICE LATER THIS MORNING AT 800 AM.

$$

MCELROY

[xtyphooncyclonex]

Tropical Storm 8 unofficially
WTPN31 PGTW 032100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE WARNING//
RMKS/
1. TROPICAL STORM 08W (EIGHT) WARNING NR 004
UPGRADED FROM TROPICAL DEPRESSION 08W
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
031800Z --- NEAR 11.5N 143.3E
MOVEMENT PAST SIX HOURS - 320 DEGREES AT 09 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
REPEAT POSIT: 11.5N 143.3E
---
FORECASTS:
12 HRS, VALID AT:
040600Z --- 12.7N 141.6E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 305 DEG/ 10 KTS
---
24 HRS, VALID AT:
041800Z --- 13.9N 139.9E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 035 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 310 DEG/ 10 KTS
---
36 HRS, VALID AT:
050600Z --- 15.2N 138.2E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 305 DEG/ 12 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
051800Z --- 16.6N 136.2E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 310 DEG/ 13 KTS
---
72 HRS, VALID AT:
061800Z --- 19.9N 131.9E
MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 105 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
095 NM SOUTHWEST QUADRANT
100 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 340 DEG/ 14 KTS
---
LONG RANGE OUTLOOK:
---
96 HRS, VALID AT:
071800Z --- 25.0N 129.7E
MAX SUSTAINED WINDS - 105 KT, GUSTS 130 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 005 DEG/ 14 KTS
---
120 HRS, VALID AT:
081800Z --- 30.6N 130.1E
MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
032100Z POSITION NEAR 11.8N 142.9E.
TROPICAL STORM 08W (EIGHT), LOCATED APPROXIMATELY 162 NM SOUTHWEST
OF ANDERSEN AFB, GUAM, HAS TRACKED NORTHWESTWARD AT 09 KNOTS OVER
THE PAST SIX HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 031800Z IS 14
FEET. NEXT WARNINGS AT 040300Z, 040900Z, 041500Z AND 042100Z.//

[richard-K2013]

NEOGURI is born!!

** WTPQ20 RJTD 040000 ***
RSMC TROPICAL CYCLONE ADVISORY
NAME TS 1408 NEOGURI (1408) UPGRADED FROM TD
ANALYSIS
PSTN 040000UTC 12.0N 142.0E FAIR
MOVE NW 15KT
PRES 998HPA
MXWD 035KT
GUST 050KT
30KT 180NM
FORECAST
24HF 050000UTC 14.5N 139.2E 70NM 70%
MOVE NW 10KT
PRES 980HPA
MXWD 055KT
GUST 080KT
48HF 060000UTC 17.0N 135.2E 140NM 70%
MOVE WNW 11KT
PRES 965HPA
MXWD 070KT
GUST 100KT
72HF 070000UTC 19.9N 131.1E 210NM 70%

[stormcruisin]

08W EIGHT 140704 0000 12.5N 142.2E WPAC 45 989

[euro6208]

Winds are up to 45 knots and peak intensity is forecast to become a strong category 4 125 knot typhoon!

WDPN31 PGTW 040300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 08W (EIGHT)
WARNING NR 05//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 08W (EIGHT), LOCATED APPROXIMATELY 173 NM WEST-
SOUTHWEST OF ANDERSEN AFB, GUAM, HAS TRACKED NORTHWESTWARD AT 13
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI), IN ASSOCIATION WITH RADAR IMAGERY FROM GUAM, DEPICTS
A QUICKLY CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC) WITH A
DEVELOPING EYEWALL APPARENT IN A RECENT 032214Z SSMIS MICROWAVE PASS.
BUILDING CONVECTIVE BANDING ALONG THE EASTERN AND NORTHERN QUADRANTS
CONTINUES TO WRAP MORE TIGHTLY INTO THE LLCC, INCREASING THE ACCURACY
FOR THE POSITIONING OF TS 08W. BASED ON THE PREVIOUSLY LISTED SSMIS
IMAGE, THE INTENSITY HAS BEEN INCREASED TO 45 KNOTS TO ACCOUNT FOR
THE IMPROVING EYEWALL STRUCTURE. DVORAK ESTIMATES REMAIN IN THE 2.0
TO 2.5 RANGE, AND APPEARS TO BE ON THE LOW SIDE FOR THE CURRENT
STRUCTURE OF TS 08W. A DEEP LAYERED SUBTROPICAL RIDGE (STR) REMAINS
THE DOMINANT STEERING INFLUENCE FOR TS 08W.
3. FORECAST REASONING.
A. THE INTENSITY FORECAST HAS BEEN INCREASED AT ALL POSITIONS DUE
TO THE RECENT IMPROVEMENTS IN STRUCTURE. THE PEAK INTENSITY HAS
BEEN INCREASED TO 125 KTS AT TAU 96.
B. TS 08W IS FORECAST TO TRACK WEST-NORTHWESTWARD TO NORTHWESTWARD
THROUGH TAU 72 ALONG THE SOUTHERN PERIPHERY OF THE STR. MID-LATITUDE
TRANSITORY LOWS WILL BEGIN TO MODIFY THE WESTERN EXTENT OF THE STR,
ALLOWING FOR AN INCREASED NORTH-NORTHWESTWARD TRACK AROUND TAU 72.
MODEL GUIDANCE REMAINS CONSISTENT OVER THE PAST 18 HOURS, WITH TS 08W
TURNING TO THE NORTH APPROXIMATELY 120 NM EAST OF OKINAWA. THE
POSSIBILITY OF ADDITIONAL WESTWARD DRIFT COULD OCCUR BETWEEN TAU 72
AND 96 AND WILL BE CLOSELY MONITORED. TS 08W WILL CONTINUE TO
INTENSIFY THROUGH TAU 96 AS IT TRACKS OVER VERY FAVORABLE SEA SURFACE
TEMPERATURES (SST), WITH A STONG SOUTHWESTWARD OUTFLOW CHANNEL AND
AN IMPROVING POLEWARD OUTFLOW CHANNEL.
C. IN THE EXTENDED TAUS, TS 08W IS EXPECTED TO TRACK POLEWARD
ALONG THE WESTERN PERIPHERY OF THE STR, TURNING TO THE NORTH-
NORTHEAST BY TAU 120 AS THE STR BEGINS TO SEE INCREASED INFLUENCE
FROM A MID-LATITUDE SHORTWAVE TROUGH. WITH THE EXCEPTION OF GFDN,
WHICH IS SLOWER AND FURTHER WEST, THE DYNAMIC GUIDANCE IS IN GOOD
AGREEMENT. TS 08W IS EXPECTED TO INTENSIFY TO A PEAK INTENSITY OF
125 KNOTS BY TAU 96 DUE TO THE IMPROVED POLEWARD OUTFLOW. BY TAU 120
THE INCREASED MID-LATITUDE INTERACTION, DECREASING SST VALUES, AND
THE START OF LAND INTERACTION WILL BEGIN THE WEAKENING PROCESS.
ALTHOUGH THE TS 08W WILL REMAIN AN INTENSE SYSTEM AS IT MAKES LAND-
FALL INTO SOUTHERN JAPAN. THE CONFIDENCE IN THE FORECAST TRACK HAS
INCREASED TO HIGH AS THE MODEL GUIDANCE HAS TIGHTEN FURTHER THROUGH
TAU 120, EXCLUDING GFDN WHICH REMAINS WELL TO THE WEST.//
NNNN

[stormcruisin]

Lots of low level cloud indication of of future eyewall .


wrapping deep convention throughout the bands around the llcc look forr RI when a little more organised.


moisture laden with the sst temps as they are the evaporation from the fiction heat should fuel a super ty imo.

[RL3AO]

How high will it go? Over/under 140kt 1-min

[euro6208]

000
WTPQ31 PGUM 040301
TCPPQ1

TROPICAL STORM NEOGURI (08W) ADVISORY NUMBER 5
NATIONAL WEATHER SERVICE TIYAN GU WP082014
200 PM CHST FRI JUL 4 2014

...TROPICAL STORM NEOGURI (08W) IS 210 MILES WEST-SOUTHWEST OF GUAM
AND MOVING TOWARD THE NORTHWEST...

WATCHES AND WARNINGS
--------------------
NONE.

SUMMARY OF 100 PM CHST...0300 UTC...INFORMATION
-----------------------------------------------

LOCATION...12.8N 141.7E

ABOUT 210 MILES WEST-SOUTHWEST OF GUAM
ABOUT 250 MILES WEST-SOUTHWEST OF ROTA
ABOUT 300 MILES WEST-SOUTHWEST OF TINIAN
ABOUT 315 MILES WEST-SOUTHWEST OF SAIPAN
ABOUT 245 MILES NORTHEAST OF ULITHI
ABOUT 335 MILES NORTHEAST OF YAP AND
ABOUT 625 MILES NORTHEAST OF KOROR.

MAXIMUM SUSTAINED WINDS...50 MPH
PRESENT MOVEMENT...NORTHWEST AT 15 MPH

DISCUSSION AND OUTLOOK
----------------------

AT 100 PM CHST...0300 UTC...THE CENTER OF TROPICAL STORM NEOGURI
WAS LOCATED BY SATELLITE NEAR LATITUDE 12.8 DEGREES NORTH AND
LONGITUDE 141.7 DEGREES EAST.

TROPICAL STORM NEOGURI IS MOVING NORTHWESTWARD AT 15 MPH. NEOGURI IS
EXPECTED TO CONTINUE MOVING IN THIS GENERAL DIRECTION AND SPEED
THROUGH TONIGHT AND SATURDAY.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO 50 MPH. TROPICAL STORM
NEOGURI IS EXPECTED TO INTENSIFY AND MAY BECOME A TYPHOON LATE
TONIGHT AND CONTINUE TO INTENSIFY THROUGH THROUGH SUNDAY.

NEXT ADVISORY
-------------

THE NEXT SCHEDULED ADVISORY ON TROPICAL STORM NEOGURI WILL BE ISSUED
BY THE NATIONAL WEATHER SERVICE THIS EVENING AT 800 PM.

$$

SIMPSON

[dexterlabio]

Impressive banding for a tropical storm. I'd say a high chance to be the first Category 5 tropical cyclone in the NHem this year.

[dexterlabio]

Its size is also impressive. I don't know if it's a monsoon-depression type but its huge circulation doesn't look to be a problem, IMO..

[euro6208]

It has that eyelike feature and the northern periphery is now filling in with deeper convection. Very favorable outflow and sst's are superb. I'm thinking this could become our 1st category 5 this year...

[stormcruisin]

ADT numbers sky rocketing

2014JUL04 033200 4.4 977.5 74.6 4.4 5.0 5.3 1.7T/6hr OFF OFF

http://www.ssd.noaa.gov/PS/TROP/DATA/20 ... W-list.txt

[stormcruisin]

Its size is also impressive. I don't know if it's a monsoon-depression type but its huge circulation doesn't look to be a problem, IMO..

Circulation size should not be a problem its track is over clear open ocean.

[stormcruisin]

08W NEOGURI 140704 0600 13.1N 141.4E WPAC 55 982


That's one hell of a eye-wall structure being modeled by Saturday.

[ManilaTC]

The first microwave sensors pictures out of the new NASA GPM and AMSR-2 have been awesome.

[stormcruisin]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.2.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 04 JUL 2014 Time : 073000 UTC
Lat : 13:24:31 N Lon : 141:11:35 E


CI# /Pressure/ Vmax
4.4 / 978.2mb/ 74.6kt

Over due for a upgrade going by ADT

[euro6208]

Up to 55 knots!

WDPN31 PGTW 040900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 08W (NEOGURI)
WARNING NR 06//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 08W (NEOGURI), LOCATED APPROXIMATELY 207 NM
WEST OF ANDERSEN AFB, HAS TRACKED NORTHWESTWARD AT 13 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
DEPICTS A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH
TIGHTLY-CURVED BANDING WRAPPING INTO A PARTIALLY-EXPOSED CENTER. A
040727Z SSMIS IMAGE INDICATES DEEP CONVECTIVE BANDING PRIMARILY OVER
THE SOUTHERN SEMI-CIRCLE; HOWEVER, BANDING HAS IMPROVED
SIGNIFICANTLY OVER THE NORTH QUADRANT OVER THE PAST SIX HOURS AND
THERE IS A WELL-DEFINED MICROWAVE EYE FEATURE. THEREFORE, THERE IS
GOOD CONFIDENCE IN THE INITIAL POSITION AND RECENT TRACK MOTION. THE
INITIAL INTENSITY IS ASSESSED AT 55 KNOTS BASED ON THE IMPROVED
STRUCTURE AND A DVORAK INTENSITY ESTIMATE OF 55 KNOTS FROM PGTW. TS
08W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP SUBTROPICAL
RIDGE (STR) ENTRENCHED TO THE NORTH.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TS 08W IS FORECAST TO TRACK GENERALLY NORTHWESTWARD THROUGH
TAU 72 AS THE SYSTEM TRACKS ALONG THE SOUTHWEST PERIPHERY OF THE STR.
DYNAMIC MODEL GUIDANCE IS GOOD AGREEMENT WITH A 160 NM SPREAD IN
SOLUTIONS AT TAU 72. FORECAST UNCERTAINTY IS MAINLY ATTRIBUTED TO
MINOR DIFFERENCES IN HOW THE STR IS DEPICTED. BASED ON THE 04/00Z
500 MB ANALYSIS, THE STR HAS MAINTAINED STRENGTH OVER THE PAST 24
HOURS AND IS ORIENTED EAST-WEST, EXTENDING AS FAR WEST AS TAIWAN. TS
08W IS FORECAST TO RAPIDLY INTENSIFY THROUGH THE NEXT 48 HOURS DUE
TO FAVORABLE UPPER-LEVEL CONDITIONS AND VERY FAVORABLE SEA SURFACE
TEMPERATURES (SST) AND HIGH OCEAN HEAT CONTENT VALUES.
C. IN THE EXTENDED TAUS, TS 08W IS FORECAST TO TRACK NORTHWARD
ALONG THE WESTERN PERIPHERY OF A POLEWARD ORIENTED STR. THE SYSTEM
IS NOT EXPECTED TO ACCELERATE AND BEGIN EXTRA-TROPICAL TRANSITION
(ETT) UNTIL AFTER TAU 120 WHEN THE SYSTEM FIRST BEGINS TO ENCOUNTER
INCREASING MIDLATITUDE WESTERLIES NEAR WESTERN JAPAN AND THE EAST
SEA. DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT WITH A 175 NM
SPREAD IN SOLUTIONS AT TAU 96, NEAR OKINAWA. FORECAST TRACK
UNCERTAINTY REMAINS WITH ECMWF INDICATING A MORE WESTWARD TRACK AND
RE-CURVE JUST WEST OF OKINAWA WHILE THE REMAINDER OF THE GUIDANCE RE-
CURVES THE SYSTEM OVER OR TO THE EAST OF OKINAWA. THE DYNAMIC MODELS
ALSO INDICATE DIFFERENT TRACK SPEEDS BUT, WITH THE EXCEPTION OF
COAMPS-TC, THE MODELS SUPPORT MODEST TRACK SPEEDS 09 TO 16 KNOTS,
TYPICAL OF A POLEWARD FLOW PATTERN. DUE TO THE TIGHT MODEL
AGREEMENT, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK,
WHICH IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS BUT FASTER TO
OFFSET THE SLOW-TRACKING GFDN GUIDANCE. IT IS IMPORTANT TO NOTE THAT
THIS IS NOT THE TYPICAL RE-CURVE PATTERN, THEREFORE, THERE IS NO
NEED TO ADJUST FOR HISTORICAL MODEL BIAS (MODELS TOO SLOW AND WEST
OF THE ACTUAL TRACK), WHICH IS USED NORTH OF THE RIDGE AXIS IN A RE-
CURVE SCENARIO. IN FACT, AS MENTIONED EARLIER, THE SYSTEM DOES NOT
TRACK POLEWARD OF THE STR AXIS UNTIL AFTER TAU 120 AT WHICH POINT IT
IS EXPECTED TO RE-CURVE SHARPLY EASTWARD AND TO UNDERGO ETT. TS 08W
IS FORECAST TO WEAKEN SLIGHTLY AFTER TAU 84 WITH MORE SIGNIFICANT
WEAKENING TREND AFTER TAU 96 DUE TO INCREASING LAND INTERACTION AND
DECRAESING SST.//
NNNN