SPAC: Extratropical Cyclone 13F / Invest 90P

[1900hurricane]

An invest has been declared well east in the Tropical South Pacific, in a spot where development is more common in El Ninos. It may not have a chance to develop prior to racing off to the mid-latitudes within the next 72 hours, but brief classification is possible.

90P INVEST
As of 12:00 UTC Feb 15, 2017:

Location: 13.6°S 147.7°W
Maximum Winds: 20 kt
Minimum Central Pressure: 1007 mb

[1900hurricane]

From Fiji:

TROPICAL DISTURBANCE 13F CENTRE [1004HPA] ANALYSED NEAR 16.5S 147.8W
AT 150900UTC.
POSITION POOR BASED ON HIMAWARI IR IMAGERY WITH ANIMATION AND
PERIPHERAL SURFACE OBSERVATION. TD13F SLOW MOVING.

CONVECTION DISPLACED TO THE EAST OF THE SUPPOSED LLCC. ORGANISATION
POOR. TD13F LIES UNDER AN UPPER DIFFLUENT REGION IN A LOW SHEARED
ENVIRONMENT. SST IS AROUND 29 DEGREES CELSIUS.

GLOBAL MODELS HAVE PICKED UP THE SYSTEM AND MOVE IT SOUTHWARDS WITH
SOME INTENSIFICATION.

POTENTIAL FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN THE
NEXT 24 TO 48 HOURS IS LOW.

[Digital-TC-Chaser]

Original source: http://tgftp.nws.noaa.gov/data/raw/ab/abpw10.pgtw..txt, recovered at: 2017-02-16 0515Z

ABPW10 PGTW 160600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS/160600Z-170600ZFEB2017//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION (INVEST 90P) PREVIOUSLY LOCATED
NEAR 13.4S 148.6W IS NOW LOCATED NEAR 16.3S 148.5W, APPROXIMATELY
105NM NORTH-NORTHEAST OF PAPEETE, TAHITI, FRENCH POLYNESIA. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY DEPICTS A BROAD LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH DISORGANIZED DEEP CONVECTION FLARING
ALONG THE NORTHERN PERIPHERY. THIS SYSTEM IS LOCATED ALONG THE
LEADING EDGE OF AN UPPER-LEVEL TROUGH WITH STRONG DIFFLUENCE FUELING
THE PERSISTENT CONVECTION. A 160214Z SSMIS 37GHZ COMPOSITE IMAGE
SHOWS FRAGMENTED BANDING OVER THE NORTHERN SEMI-CIRCLE OF THE SYSTEM
WITH NO EVIDENCE OF A DEFINED CENTER OR ANY BANDING OVER THE
SOUTHERN SEMI-CIRCLE. SURFACE OBSERVATIONS FROM THE AREA INDICATE
SLP VALUES NEAR 1002 TO 1003MB BUT GENERALLY LIGHT WINDS. HOWEVER,
THE SSMIS WIND PRODUCT DID SHOW STRONGER WINDS ASSOCIATED WITH THE
CONVECTIVE BANDS TO THE NORTH. THE GLOBAL MODELS INDICATE A
SOUTHWARD TRACK AND INTENSIFICATION TREND AS THE SYSTEM MOVES UNDER
THE UPPER-LEVEL TROUGH AND TRANSITIONS TO A FULLY SUBTROPICAL
CYCLONE WITHIN THE NEXT TWO TO THREE DAYS. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1002 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.

[1900hurricane]

13F is now a Tropical Depression, and it looks like Nadi may give it their first name of the season.

TROPICAL DEPRESSION 13F CENTRE [1000HPA] ANALYSED NEAR 19.5S 146.1W
AT 162300UTC.
POSITION POOR BASED ON GOES-15 VIS/EIR IMAGERY AND PERIPHERAL SURFACE
OBSERVATION. TD13F MOVING SOUTH-SOUTHEAST AT ABOUT 10 KNOTS.

CONVECTIVE BAND PERSISTING AND GRADUALLY WRAPPING INTO LLCC FROM THE
NORTHEAST. ORGANISATION CONTINUE TO IMPROVE. TD13F LIES UNDER AN
ANTI-CIRCLONIC REGION
IN A LOW SHEARED ENVIRONMENT. CYCLONIC CIRCULATION EXTENDS UPTO
500HPA. SST IS AROUND 29 DEGREES CELSIUS.

GLOBAL MODELS HAVE PICKED UP THE SYSTEM AND MOVE IT
SOUTH-SOUTHEASTWARDS WITH GRADUAL INTENSIFICATION.

POTENTIAL FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN THE
NEXT 24 TO 48 HOURS IS MODERATE TO HIGH.

[kala]

40 kt winds, with some patches of gales closer to the center...

Not bad, should be named soon.

[Alyono]

data does not mean getting named in most basins. Dvorak seems to be all that matters

[Digital-TC-Chaser]

0451Z looked good enough for a name. Maybe the thinking is its now taking on sub-tc features.

[wxman57]

Fiji has only identified this area as a "disturbance". All disturbances are identified as "TDxx". I'm not sure if they distinguish between disturbances and depressions. They only mention that chances of this disturbance developing into a tropical cyclone are "moderate". They're not concerned about it as it is moving southward in the middle of nowhere toward the outer fringes of nowhere.

[1900hurricane]

Fiji has only identified this area as a "disturbance". All disturbances are identified as "TDxx". I'm not sure if they distinguish between disturbances and depressions. They only mention that chances of this disturbance developing into a tropical cyclone are "moderate". They're not concerned about it as it is moving southward in the middle of nowhere toward the outer fringes of nowhere.

Nadi does make distinctions between Tropical Disturbances and Tropical Depressions, although I am unaware of what those distinctions are. An example can be seen when posts #2 and #4 in this thread are referenced. I think Nadi's last mention of Tropical Depression 13F was in the last 00Z Tropical Disturbance Summary.

[Digital-TC-Chaser]

Nice look anyways.

[Steve820]

It does look great and might become subtropical anytime during the next day or two. I REALLY hope it is named! The SPac has been so inactive, it has seen no named storms and it's FEBRUARY! This must be a record inactive pace...

[euro6208]

Interesting lonely invest out in the vast south pacific..

Got my mind going alien mode wondering the kinds of living things living in an area majority unexplored. Alien bases anyone?

[1900hurricane]

What once was Tropical Depression 13F can now be seen exiting the subtropics near the southeastern portion of the satellite image below. The former depression is now analyzed as an extratropical cyclone by Wellington, and rightfully so.