WPAC: 04W - Post-Tropical

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THE AREA OF CONVECTION (INVEST 97W) PREVIOUSLY LOCATED
NEAR 13.3N 153.4E, IS NOW LOCATED NEAR 12.5N 154.0E, APPROXIMATELY
335 NM NORTH-NORTHEAST OF CHUUK. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY AND A 072333Z MHS 89GHZ MICROWAVE IMAGE DEPICTS AN ELONGATED
CIRCULATION WITH SMALL POCKETS OF FLARING CONVECTION LOCATED TO THE
SOUTH. A 072333Z ASCAT PARTIAL PASS SHOWS PRIMARILY 5-10 KNOT WINDS
WRAPPING INTO THE CENTER OF A BROAD CIRCULATION WITH HIGHER WINDS
LOCATED AROUND THE PERIPHERY. THE DISTURBANCE IS LOCATED IN AN AREA
OF GOOD DIVERGENCE ALOFT, LOW (5-10 KNOTS) VERTICAL WINDS SHEAR, AND
SEA SURFACE TEMPERATURES THAT ARE FAVORABLE FOR DEVELOPMENT (26-28
DEGREES CELSIUS). GLOBAL MODELS INDICATE THAT THE DISTURBANCE WILL
TRACK TO THE WEST-NORTHWEST OVER THE NEXT SEVERAL DAYS, BUT
CURRENTLY NO MODELS ARE INDICATING INTENSIFICATION. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. THE POTENTIAL FOR
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS REMAINS LOW.

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97W INVEST
As of 06:00 UTC May 08, 2018:

Location: 13.3°N 154.4°E
Maximum Winds: 20 kt
Minimum Central Pressure: 1006 mb

[wxman57]

It fell apart. Next...

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97W INVEST 180508 1800 14.7N 153.5E WPAC 20 1007

Big increase of convection near the center.

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THE AREA OF CONVECTION (INVEST 97W) PREVIOUSLY LOCATED
NEAR 12.5N 154.0E, IS NOW LOCATED NEAR 14.9N 153.0E, APPROXIMATELY
460 NM NORTH OF CHUUK. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND
A 082312Z MHS 89GHZ MICROWAVE IMAGE DEPICTS A FULLY EXPOSED AND
ELONGATED CIRCULATION WITH SMALL POCKETS OF FLARING CONVECTION
LOCATED TO THE EAST. A 082312Z ASCAT PARTIAL PASS SHOWS PRIMARILY 5-
10 KNOT WINDS NEAR THE CENTER OF A BROAD CIRCULATION WITH HIGHER
WINDS LOCATED AROUND THE NORTHERN PERIPHERY. THE DISTURBANCE IS
LOCATED IN AN AREA OF SLIGHTLY WORSENING DIVERGENCE ALOFT, HAS MOVED
INTO LOW TO MODERATE (10-20 KNOTS) VERTICAL WINDS SHEAR, AND SEA
SURFACE TEMPERATURES THAT ARE DECREASING BUT STILL FAVORABLE FOR
DEVELOPMENT (26-28 DEGREES CELSIUS). GLOBAL MODELS INDICATE THAT THE
DISTURBANCE WILL TRACK TO THE WEST-NORTHWEST OVER THE NEXT SEVERAL
DAYS, BUT NO MODELS ARE INDICATING INTENSIFICATION. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1008 MB. THE POTENTIAL FOR
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS REMAINS LOW.

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THE AREA OF CONVECTION (INVEST 97W) PREVIOUSLY LOCATED
NEAR 14.9N 153.0E, IS NOW LOCATED NEAR 15.2N 153.0E, APPROXIMATELY
472 NM NORTH OF CHUUK. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A
092332Z MHS METOP-A 89GHZ MICROWAVE IMAGE DEPICTS A FULLY-EXPOSED
AND DISORGANIZED CIRCULATION WITH SMALL POCKETS OF FLARING
CONVECTION LOCATED TO THE EAST. A 092332Z METOP-A ASCAT PARTIAL PASS
SHOWS PRIMARILY 5-10 KNOT WINDS NEAR THE CENTER OF A BROAD
CIRCULATION WITH 20-25 KNOT WINDS TO THE NORTH AND EAST, WHICH ARE
ASSOCIATED WITH STRAIGHTLINE GRADIENT FLOW. THE DISTURBANCE IS
LOCATED IN AN AREA OF SLIGHTLY DECREASING DIVERGENCE ALOFT, HAS
MOVED INTO MODERATE (15-20 KNOTS) VERTICAL WIND SHEAR, AND IS
PASSING OVER SEA SURFACE TEMPERATURES THAT ARE DECREASING BUT STILL
FAVORABLE FOR DEVELOPMENT (26-28 DEGREES CELSIUS). GLOBAL MODELS
INDICATE THAT THE DISTURBANCE WILL TRACK TO THE NORTHWEST OVER THE
NEXT SEVERAL DAYS, BUT NO MODELS ARE INDICATING INTENSIFICATION DUE
TO UNFAVORABLE ALONG-TRACK ENVIRONMENTAL CONDITIONS. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1010 MB. THE POTENTIAL FOR
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS REMAINS LOW.

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TXPQ23 KNES 100957
TCSWNP

A. TROPICAL DISTURBANCE (97W)

B. 10/0830Z

C. 16.1N

D. 153.1E

E. FIVE/HIMAWARI-8

F. T1.0/1.0/D1.0/24HRS

G. IR/EIR/SWIR/VIS

H. REMARKS...THIS INTENSITY ESTIMATE WAS DERIVED USING 4 KM IR
DATA. DEFINITION OF THE LLCC IS BECOMING LESS ORGANIZED. DT OF 1.0 IS
BASED ON LOOSELY DEFINED LLCC AND A CENTER LT 75 NMI FROM A SMALL COLD
OVERCAST. MET AND PT ARE 1.0. FT IS BASED ON MET.

I. ADDL POSITIONS

NIL


...RAMIREZ

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It's a fighter...

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WTPN21 PGTW 102230
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
140 NM EITHER SIDE OF A LINE FROM 16.4N 152.3E TO 18.8N 148.0E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 18 TO 23 KNOTS. METSAT
IMAGERY AT 101800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 16.7N 152.0E. THE SYSTEM IS MOVING NORTHWESTWARD AT 07
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 97W) PREVIOUSLY LOCATED
NEAR 14.9N 153.0E, IS NOW LOCATED NEAR 16.7N 152.0E, APPROXIMATELY
454 NM EAST-NORTHEAST OF ANDERSEN AB, GUAM. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY INDICATES THAT DEEP CONVECTION REMAINS VERTICALLY
SHEARED TO THE SOUTHEAST, AND GENERALLY RAGGED, BUT THE LOW LEVEL
CIRCULATION CENTER (LLCC) HAS BECOME NOTABLY MORE DEFINED AND MOVED
CLOSER TO THE EDGE OF THE CONVECTION. A 102012Z SSMIS 91GHZ
MICROWAVE IMAGE REVEALS FORMATIVE LOW-LEVEL BANDING AND FLARING DEEP
CONVECTION TO THE EAST OF THE LLCC. A 101141Z ASCAT PASS DEPICTS AN
ELONGATED WEAK CIRCULATION WITH ISOLATED HIGHER (25-30 KNOT) WINDS
WITHIN A WAVELIKE CUSP IN THE NORTHEAST PERIPHERY. UPPER LEVEL
ANALYSIS INDICATES MODERATE (15-20 KNOT) VERTICAL WIND SHEAR AND
EXCELLENT POLEWARD OUTFLOW TOWARDS AN UPPER LEVEL LOW TO
THE NORTHEAST. SEA SURFACE TEMPERATURES ARE FAVORABLE FOR
DEVELOPMENT (27-28 DEGREES CELSIUS). GLOBAL MODELS INDICATE THAT THE
DISTURBANCE WILL TRACK SLOWLY TO THE NORTHWEST OVER THE NEXT SEVERAL
DAYS WITH A SHORT WINDOW OF RELAXED SHEAR AND STRONG OUTFLOW
PROVIDING AN OPPORTUNITY FOR POTENTIAL DEVELOPMENT. IN 24 TO 36
HOURS, INVEST 97W WILL TRACK INTO AN AREA OF UNFAVORABLE UPPER
LEVEL SUPPORT DUE TO AN APPROACHING LONGWAVE TROUGH. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1009 MB. DUE TO IMPROVING
CONVECTION AND ORGANIZATION, THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
112230Z.
//
NNNN

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TPPN11 PGTW 102111

A. TROPICAL DISTURBANCE 97W (NE OF GUAM)

B. 10/2040Z

C. 16.84N

D. 151.76E

E. FIVE/HMWRI8

F. T1.0/1.0/S0.0/21HRS STT: S0.0/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: 49A/PBO PTLY XPSD LLCC/ANMTN. CNVCTN WRAPS .25 ON
LOG10 SPIRAL YIELDING A DT OF 1.0. MET AND PT AGREE. DBO DT.

I. ADDITIONAL POSITIONS:
10/1821Z 16.53N 151.95E MMHS
10/2012Z 16.65N 151.92E SSMS


LOWE


TXPQ23 KNES 102118
TCSWNP

A. TROPICAL DISTURBANCE (97W)

B. 10/2030Z

C. 17.2N

D. 151.9E

E. THREE/HIMAWARI-8

F. T1.5/1.5/D1.0/24HRS

G. IR/EIR/VIS/SSMIS

H. REMARKS...THE SYSTEM IS CHARACTERIZED BY CIRCULARLY DEFINED CLOUD
LINES NEAR OR UNDER A SMALL OVERCAST THAT RESULTS IN DT=2.0. MET=1.5
AND PT=1.5. FT IS BASED ON MET BECAUSE THE CONVECTION IS NOT STEADY.

I. ADDL POSITIONS

10/1819Z 17.0N 151.9E SSMIS


...BOLL

[StruThiO]

stubborn little thing

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000
WWMY80 PGUM 110808 AAA
SPSMY

Special Weather Statement...UPDATED
National Weather Service Tiyan GU
608 PM ChST Fri May 11 2018

GUZ004-120400-
Saipan-
608 PM ChST Fri May 11 2018

Resent for corrected expiration time

The Joint Typhoon Warning Center has issued a Tropical Cyclone
Formation Alert on a tropical disturbance centered about 430 miles
east-northeast of Saipan and 408 miles east of Alamagan at 1030 AM
this morning. Satellite data indicate that the strongest winds of
20 to 25 mph are found northeast of the center.

A tropical depression is likely to develop late this afternoon or
this evening, and track slowly northwest, passing the far northern
Mariana Islands Saturday night or Sunday morning. Current indications
are that this system is not likely to develop beyond tropical
depression intensity, and that strongest winds are likely to remain
north and northeast of the center.

For Agrihan, Pagan, and Alamagan islands, gusty winds and locally
heavy showers are possible over the weekend as this system passes,
but tropical storm conditions are not expected. Even so, residents
of these islands should keep aware of the progress of the disturbance
and keep up with the latest statements from the National Weather
Service and the Saipan Homeland Security Office.

$$

Middlebrooke

[euro6208]

Very impressive. Convection much more stronger than TD 01E ever got. It is at least a TD or a TS now...

I’ve seen worst looking TS in the Atlantic than this.

Dvorak at 1.5 from both agencies.

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WDPN31 PGTW 120300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 04W (FOUR)
WARNING NR 01//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION 04W (FOUR), LOCATED APPROXIMATELY 378 NM
NORTHEAST OF ANDERSEN AFB, HAS TRACKED NORTHEASTWARD AT 09 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
REVEALS PERSISTENT DEEP CONVECTIVE ACTIVITY NEAR AN OCCLUDED LOW
LEVEL CIRCULATION CENTER (LLCC) WITH OVERSHOOTING CONVECTIVE TOPS
SURROUNDING THE ASSESSED LLCC POSITION. THE INITIAL POSITION IS
PLACED WITH MODERATE CONFIDENCE BASED ON AN ASSESSMENT OF THE
OVERALL LOW LEVEL CLOUD BANDS AND EXTRAPOLATION OF AN 112018Z
WINDSAT 37GHZ MICROWAVE IMAGE WITH A WELL DEFINED LLCC AND
FORMATIVE CONVECTIVE BANDING IN THE NORTHERN AND EASTERN QUADRANTS,
WITH WEAKER LOW LEVEL BANDING TO THE SOUTH. THE INITIAL INTENSITY
OF 30 KNOTS IS BASED ON MULTI-AGENCY DVORAK CURRENT INTENSITY
ESTIMATES RANGING FROM T1.5 (25 KNOTS) FROM PGTW AND KNES
RESPECTIVELY AND ANALYSIS OF A PARTIAL OSCAT PASS FROM 112130Z. THE
AFOREMENTIONED OSCAT PASS REVEALED 25-30 KNOT WINDS CONFINED TO THE
NORTHEASTERN HEMISPHERE OF THE SYSTEM, MOSTLY ASSOCIATED WITH A
STRONG GRADIENT BETWEEN TD 04W AND A SUBTROPICAL HIGH TO THE NORTH,
AND ONLY 15-20 KNOTS IN THE SOUTHWESTERN QUADRANTS. ALTHOUGH ALL
RECENT SCATTEROMETER PASSES WERE MISSES, BASED ON THE PERSISTENCE
OF THE DEEP CONVECTION IN THE VICINITY OF THE LLCC, AND THE OVERALL
IMPROVEMENT IN THE CONVECTIVE SIGNATURE, IT IS LIKELY THAT SOME
HIGHER SPEED WINDS HAVE STARTED TO WRAP INTO AND AROUND THE LLCC.
ENVIRONMENTAL ANALYSIS SHOWS THE SYSTEM IS TAPPING INTO A STRONG
POLEWARD OUTFLOW CHANNEL THAT IS ENHANCED BY THE MID-LATITUDE FLOW
AHEAD OF AN APPROACHING TROUGH. THIS ENHANCED OUTFLOW IS OFFSETTING
THE HIGH (20-30 KNOTS) VWS. SSTS IN THE AREA ARE WARM (29-30
CELSIUS) AND PROVIDE AMPLE SUPPORT FOR INTENSIFICATION. THE SYSTEM
IS CURRENTLY TRACKING NORTHWESTWARD ALONG THE SOUTHERN BOUNDARY OF
A SUBTROPICAL RIDGE LOCATED TO THE NORTHEAST.
3. FORECAST REASONING.
A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE
FORECAST PHILOSOPHY.
B. TD 04W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD UNDER
THE INFLUENCE OF THE STEERING RIDGE TO THE NORTHEAST THROUGH TAU
36. FROM TAU 36 TO THE END OF THE FORECAST, THE SYSTEM WILL SLOW IN
FORWARD TRANSLATION WHILE SLOWING TURNING MORE NORTHWARD. THE
SYSTEM WILL INTENSIFY ONLY SLIGHTLY IN A WEAKLY FAVORABLE
ENVIRONMENT WITH STRONG OUTFLOW OFFSETTING HIGH VWS, PEAKING OUT AT
35 KNOTS WITHIN THE FIRST 12 HOURS. THE TROPICAL STORM STRENGTH
WIND FIELD WILL REMAIN CONCENTRATED IN THE NORTHEAST QUADRANT, WITH
THE 35 KNOT WIND RADII EXTENDING UP TO 180 NM TO THE NORTHEAST OF
THE LLCC. AFTER TAU 36 POINT, VWS STRENGTHENS AND COMES TO DOMINATE
THE OUTFLOW, WHICH IN CONJUNCTION WITH INCREASING DRY AIR
ENTRAINMENT AND UPPER-LEVEL MASS CONVERGENCE ASSOCIATED WITH A
DEVELOPING UPPER LEVEL LOW, WILL LEAD TO DISSIPATION BY TAU 48. THE
MAJORITY OF THE AVAILABLE DYNAMIC MODELS ARE IN GOOD AGREEMENT,
WITH HWRF BEING THE WESTERNMOST OUTLIER, AND COTC BEING THE FAR
POLEWARD OUTLIER. HOWEVER, ALL MODELS ARE IN GENERAL AGREEMENT THAT
THE SYSTEM WILL TRACK TO THE NORTHWEST. INTENSITY GUIDANCE IS A
MIXED BAG, WITH HWRF SHOWING LITTLE TO NO INTENSIFICATION, WHILE
THE COAMPS MODELS AND DECAY SHIPS INDICATE A PEAK BETWEEN 35 AND 40
KNOTS. THE OVERALL UNCERTAINTY IN THE MODEL GUIDANCE LENDS LOW
CONFIDENCE IN THE JTWC FORECAST.//
NNNN

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

----- Current Analysis -----
Date : 12 MAY 2018 Time : 044000 UTC
Lat : 18:53:59 N Lon : 148:17:22 E


CI# /Pressure/ Vmax
2.2 /1007.9mb/ 32.0kt


Final T# Adj T# Raw T#
2.2 2.4 2.4

Center Temp : -1.4C Cloud Region Temp : -39.3C

Scene Type : CURVED BAND with 0.50 ARC in LT GRAY

Positioning Method : FORECAST INTERPOLATION

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

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : N/A
- Environmental MSLP : 1012mb

Satellite Name : HIM-8
Satellite Viewing Angle : 23.8 degrees

****************************************************

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WDPN31 PGTW 120900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 04W (FOUR)
WARNING NR 02//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION (TD) 04W (FOUR), LOCATED APPROXIMATELY 376 NM
NORTH-NORTHEAST OF ANDERSEN AFB, HAS TRACKED NORTHWESTWARD AT 08
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY SHOWS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC)
WITH THE DEEPEST CONVECTION LOCATED TO THE EAST OF THE LLCC. THE
INITIAL POSITION IS BASED ON A 120519Z SSMIS 91GHZ MICROWAVE IMAGE
WHICH SHOWS A DEFINED CIRCULATION WITH DEEP CONVECTION CONFINED TO
THE EASTERN HALF OF THE SYSTEM. THE INITIAL INTENSITY OF 30 KNOTS IS
HEDGED BETWEEN A 120312Z SATCON ESTIMATE OF 34 KNOTS AND A PGTW
DVORAK ESTIMATE OF T1.5 (25 KNOTS). UPPER LEVEL ANALYSIS SHOWS
UNFAVORABLE VERTICAL WIND SHEAR BETWEEN 25 AND 30 KNOTS WHICH IS
SHEARING THE CONVECTION TO THE EAST OF THE LLCC. TD 04W IS BENEFITING
FROM GOOD POLEWARD OUTFLOW. HOWEVER, EQUATORWARD OUTFLOW IS VERY
WEAK. SEA SURFACE TEMPERATURES ARE FAVORABLE FOR ADDITIONAL
DEVELOPMENT RANGING BETWEEN 28 AND 29 DEGREES CELSIUS. TD 04W IS
TRACKING AROUND THE 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. TD 04W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD AROUND
THE STR THROUGH TAU 24. TD 04W WILL THEN TRACK NORTH-NORTHWESTWARD
THROUGH TAU 48 AS IT INTERACTS WITH A SHORT-WAVE TROUGH MOVING FROM
WEST TO EAST. MARGINAL ENVIRONMENTAL CONDITIONS, WARM SEA SURFACE
TEMPERATURES AND GOOD POLEWARD OUTFLOW, WILL ALLOW FOR MINOR
INTENSIFICATION TO 35 KNOTS BETWEEN TAU 12 AND TAU 24. HOWEVER,
BEYOND TAU 24 STRONG VERTICAL WIND SHEAR ALONG WITH COOLER SEA
SURFACE TEMPERATURES WILL CAUSE TD 04W TO WEAKEN AND EVENTUALLY
DISSIPATE BY TAU 48. DYNAMIC MODEL GUIDANCE IS GENERALLY IN GOOD
AGREEMENT, INDICATING A NORTHWESTWARD AND THEN NORTH-NORTHWESTWARD
TRACK WITH ONLY MINOR INTENSIFICATION IN THE SHORT TERM. OVERALL,
THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.//
NNNN

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Fully exposed LLC.