WPAC: Invest 91W TCFA (Tropical Depression)

[Chacor]

WARNING.
TROPICAL DEPRESSION 1006 HPA
AT 23.9N 134.3E SEA SOUTH OF JAPAN MOVING WESTNORTHWEST SLOWLY.
POSITION FAIR.
MAX WINDS 30 KNOTS NEAR CENTER.




Remarkably far north for formation... east of Okinawa!

WTPN21 PGTW 220230
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
140 NM EITHER SIDE OF A LINE FROM 23.8N 134.7E TO 25.8N 130.0E
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 15 TO 20 KNOTS. METSAT IM-
AGERY AT 220130Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 24.1N 134.0E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 08
KNOTS.
2. REMARKS: RECENT ANIMATED MULTISPECTRAL SATELLITE IMAGERY REVEALS
A WELL-DEFINED, PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC)
WITH FLARING, PERSISTENT DEEP CONVECTION OVER THE NORTH QUADRANT.
A 212047Z QUIKSCAT IMAGE INDICATED AT LEAST 20-KNOT UNFLAGGED WINDS
NEAR THE CENTER WITH SUSPECT 25-KNOT UNFLAGGED WINDS UNDER THE DEEP
CONVECTION. A 212325Z TRMM IMAGE DEPICTS WEAK CONVECTIVE BANDING
AND CONVERGENT FLOW OVER THE EASTERN SEMI-CIRCLE WITH A LARGE BURST
OF DEEP CONVECTION OVER THE NORTHEAST QUADRANT. UPPER LEVEL ANALYSIS
INDICATES MODERATE VERTICAL WIND SHEAR OVER THE WESTERN HALF OF THE
DISTURBANCE DUE TO AN UPPER LOW LOCATED JUST NORTH OF OKINAWA WHICH
IS PRODUCING CONVERGENT UPPER FLOW AND HINDERING OUTFLOW. THIS LOW
IS FORECAST TO DISSIPATE OVER THE NEXT 24 HOURS WITH A CORRESPONDING
DECREASE IN SHEAR. THEREFORE, THE LLCC IS EXPECTED TO SLOWLY
CONSOLIDATE UNDER AN IMPROVING ENVIRONMENT. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 18 TO 22 KNOTS. MINIMUM SEA LEVEL PRESSURE
IS ESTIMATED TO BE NEAR 1005 MB. THE POTENTIAL FOR THE DEVELOPMENT
OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS
UPGRADED TO GOOD.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED
BY 230230Z.//

[Typhoon Hunter]

Thanks for posting this Chacor, JMA already listing it as a TD:

WARNING.TROPICAL DEPRESSION 1006 HPAAT 23.9N 134.3E SEA SOUTH OF JAPAN MOVING WESTNORTHWEST SLOWLY.POSITION FAIR.MAX WINDS 30 KNOTS NEAR CENTER.

[Coredesat]

The shear doesn't quite look like it's decreased; the center is definitely exposed on VIS:

[Simone Lussardi]

What a ***** year for WPAC again.... Here in southern China (near Hong Kong) TC fans are waiting for a cyclone since 2003. Not another year like this please !!!!!!!

This far north formation is indication of a continued reversed monsoon trough, which spawns cyclones far north and in a "S" track or north track, while the ridge that is supposed to push them WNW from Guam to south China is sitting in the middle of the Pacific. And is very strange since ENSO and QBO are negative... It should be a good year for cyclones in south China.

Bye,
Simone

[Simone Lussardi]

Thanks for posting this Chacor, JMA already listing it as a TD:

WARNING.TROPICAL DEPRESSION 1006 HPAAT 23.9N 134.3E SEA SOUTH OF JAPAN MOVING WESTNORTHWEST SLOWLY.POSITION FAIR.MAX WINDS 30 KNOTS NEAR CENTER.

Didn't notice you

Great video James !!!!! That eyewall was powerful enough.

To return on topic, ECMWF does not see the depression at all, it sees something toward the 240.000 hours, but somewhere near Wake island..

[Chacor]

You guys had Pabuk move through earlier this year, though, that one took fairly long to dissipate (only became extratropical west of Korea!)

91W looking poor right now. Let's see what DMAX does to it.

[Simone Lussardi]

You guys had Pabuk move through earlier this year, though, that one took fairly long to dissipate (only became extratropical west of Korea!)

91W looking poor right now. Let's see what DMAX does to it.

Hi,
Pabuk ? Its diameter of maximum winds was 20 km lollll The last good wind here in almost all locations has been last year Typhoon Prapiroon.

The real good one I remember was Imbudo in 2003 (tropical storm force winds up to 300 km inland) and Dujuan also in 2003, which hit directly Shenzhen and crossed south of my location. That was some night...

[Simone Lussardi]

JTWC cancelled TCFA for 91W, which was very obviously being sheared apart.

JTWC issued a POOR for 92W this morning. ECMWF forecast the disturbance to move slowly west and dissipate east of Luzon by 96/120 hours.

JTWC said the shear is moderate over the disturbance, but if we see the CIMSS analysis it's very weak (< 10kt) and decreasing too. So... I don't know where they see the shear. If we look at the sat it matches more with CIMSS analysis, we do see convection decreasing but not sheared apart, unless the shear is inserted in a middle level layer and not stacked uniformly.

ECMWF still forecast something to form towards the end of the period (240 hours) in the far western Pacific.

By the disposition of the low pressure areas axis, is very obvious that ECMWF forecast something to form exactly when the ITCZ becomes reversed (from lower Philippines up to 25N 150E).

There is only a ridge along the far equator, to push the systems north.