CPAC: INVEST 92W

[Meow]

Formerly 91C, it has crossed the International Date Line.

[Meow]

AN AREA OF CONVECTION HAS PERSISTED NEAR 22.9N 179.1E,
APPROXIMATELY 370 NM SOUTH-SOUTHWEST OF MIDWAY ISLAND. ANIMATED
INFRARED SATELLITE IMAGERY SHOWS A WELL-DEFINED LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH FLARING CENTRAL CONVECTION QUICKLY
SHEARING OFF TO THE EAST. A 080739Z SSMIS 91 GHZ MICROWAVE IMAGE
DEPICTS THE TIGHTLY WRAPPED LLCC WITH DEEP CONVECTION CONTAINED TO
THE EAST. RECENT SCATTEROMETER IMAGERY (072352Z OSCAT AND 080839Z
ASCAT) INDICATE 15 KNOTS IN THE LLCC WITH 20-25 KNOTS OVER THE
EASTERN PERIPHERY. THE HISTORY OF THIS LLCC IS MUCH LIKE THAT OF TS
13W (KIROGI) IN THAT IT WAS PRODUCED BY A TROPICAL UPPER
TROPOSPHERIC TROUGH (TUTT) CELL THAT REACHED DOWN TO THE SURFACE AS
A SUBTROPICAL SYSTEM. CURRENTLY THERE ARE NO AMSU CROSS-SECTIONS
AVAILABLE TO EVALUATE THE CORE TEMPERATURE CHARACTERISTICS OF THIS
DISTURBANCE BUT PHASE SPACE MODEL OUTPUT SUGGESTS IT IS A SHALLOW
WARM-CORE WHICH WILL TRANSITION TO A COLD-CORE SYSTEM OVER THE NEXT
FEW DAYS. RECENT SURFACE OBSERVATIONS FROM MIDWAY ISLAND INDICATE
VERY HIGH PRESSURE NEAR 1013 MB. UPPER-LEVEL ANALYSIS REVEALS THE
LLCC TO BE UNDER VERY STRONG (40-50 KNOTS) WESTERLY VERTICAL WIND
SHEAR (VWS) WITH STRONG UPPER-LEVEL CONVERGENCE TO THE NORTH AND
WEST ASSOCIATED WITH A TUTT CELL TO THE NORTH OF THE LLCC. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM
SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1009 MB. SEA SURFACE
TEMPERATURE RANGES FROM 26 TO 27 DEGREES CELSIUS. DUE TO THE
UNFAVORABLE UPPER-LEVEL ENVIRONMENT, THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS LOW.

[euro6208]

weak...

[Meow]

weak...

TROPICAL DEPRESSION 1008 HPA AT 23N 179E ALMOST STATIONARY.

[euro6208]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 22.9N
179.1E, IS NOW LOCATED NEAR 23.0N 178.5E, APPROXIMATELY 385 NM
SOUTHWEST OF MIDWAY ISLAND. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY SHOWS AN AREA OF MINIMAL FLARING CONVECTION, QUICKLY BEING
SHEARED OFF TO THE EAST, FROM A WELL-DEFINED LOW-LEVEL CIRCULATION
CENTER (LLCC). UPPER-LEVEL ANALYSIS INDICATES THAT THE LLCC LIES
JUST FIVE DEGREES SOUTHEAST OF A TROPICAL UPPER TROPOSPHERIC TROUGH
(TUTT) CELL, WHICH IS PROVIDING STRONG (30 TO 40 KNOT) WESTERLY
VERTICAL WIND SHEAR (VWS). THE PROXIMITY TO THE AFOREMENTIONED TUTT
CELL ALSO HAS THE SYSTEM IN AN AREA WITH CONVERGENT WINDS JUST TO
THE NORTH, CREATING UNFAVORABLE UPPER-LEVEL CONDITIONS. A 090051Z
89 GHZ AMSU-B MICROWAVE IMAGE CONFIRMS THE LACK OF DEEP CONVECTION,
AND DEPICTS A FULLY-EXPOSED LLCC. A 090042Z PARTIAL OCEANSAT PASS
SHOWS A FAIRLY SYMMETRICAL LLCC, WITH SOME 20 KNOT WIND BARBS ON
THE NORTHERN PERIPHERY, AND 10 TO 15 KNOTS TO THE SOUTH AND WEST.
CURRENTLY THERE ARE NO AMSU CROSS-SECTIONS AVAILABLE TO EVALUATE
THE CORE TEMPERATURE CHARACTERISTICS OF THIS DISTURBANCE BUT PHASE
SPACE MODEL OUTPUT SUGGESTS IT IS A SHALLOW WARM-CORE WHICH WILL
TRANSITION TO A COLD-CORE SYSTEM OVER THE NEXT FEW DAYS. RECENT
SURFACE OBSERVATIONS FROM MIDWAY ISLAND CONTINUE TO INDICATE VERY
HIGH PRESSURES NEAR 1012 MB, WHICH IS DOWN 2 MB OVER THE PAST 24
HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1009 MB.
DUE TO THE UNFAVORABLE UPPER-LEVEL ENVIRONMENT, THE POTENTIAL FOR
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT
24 HOURS REMAINS LOW.

[euro6208]

upgraded to HIGH...

WTPN21 PGTW 101200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 27.4N 177.8E TO 35.7N 176.0W
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 15 TO 20 KNOTS. METSAT IMAGERY AT
101130Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 27.5N
178.5E. THE SYSTEM IS MOVING NORTH-NORTHEASTWARD AT 07 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 26.9N
178.1E, IS NOW LOCATED NEAR 27.5N 178.5E, APPROXIMATELY 220 NM WEST-
SOUTHWEST OF MIDWAY ISLAND. RECENT ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY SHOWS A WELL-DEFINED LOW-LEVEL CIRCULATION CENTER
(LLCC) WITH FLARING DEEP CENTRAL CONVECTION QUICKLY BEING SHEARED
OFF TO THE NORTH-NORTHEAST. A 100603Z CORIOLIS 37 GHZ MICROWAVE
IMAGE REVEALS THE TIGHTLY WOUND LLCC WITH THE DEEPEST CONVECTION
CONTAINED TO THE NORTHEASTERN PERIPHERY. RECENT SCATTEROMETER PASSES
(092223Z ASCAT AND 092352Z OSCAT) INDICATE 15-20 KNOT WINDS NEAR THE
CENTER AND 25-30 KNOT WINDS ALONG THE EASTERN PERIPHERY INDUCED BY
GRADIENT FLOW BETWEEN THE DISTURBANCE AND A DEEP-LAYERED SUBTROPICAL
RIDGE (STR) CENTERED TO THE EAST. UPPER-LEVEL ANALYSIS INDICATES
THAT THE LLCC LIES FIVE DEGREES DUE EAST OF A TROPICAL-UPPER
TROPOSPHERIC TROUGH CELL, WHICH IS PROVIDING FOR STRONG (20 TO 30
KNOTS) SOUTHWESTERLY VERTICAL WIND SHEAR (VWS). NUMERICAL MODEL
GUIDANCE SUGGESTS THAT A MID-LATITUDE TROUGH, CURRENTLY DEEPENING
OVER THE NORTHERN PACIFIC, WILL WEAKEN AND RE-ORIENTATE THE STR TO A
ZONAL AXIS. THIS WILL ALLOW FOR A TEMPORARY EASING OF VWS AND
CONNECTION TO POLEWARD OUTFLOW, WHICH COULD POSSIBLY ALLOW THE
CENTRAL CONVECTION TO PERSIST OVER THE LLCC. HOWEVER, BY THE 36-48
HOUR TIMEFRAME, THE LLCC WILL BECOME ABSORBED INTO THE DEEP TROUGH
AND SHOULD UNDERGO AN EXTRA-TROPICAL TRANSITION. SEA SURFACE
TEMPERATURES IN THE AREA ARE FAVORABLE FOR TROPICAL CYCLONE
DEVELOPMENT RANGING FROM 26 TO 27 DEGREES CELSIUS BUT SHARPLY DROP
WELL BELOW 26C POLEWARD OF 30N. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1007 MB. DUE TO NEAR WARNING THRESHOLD WINDS OBSERVED IN
THE SCATTEROMETER DATA AND INDICATIONS OF IMPROVING UPPER-LEVEL
CONDITIONS, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT
TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.

[Meow]

It has entered the Central Pacific Ocean again.