WPAC: Tropical Depression (Invest 99W) - Discussion

[wyq614]

(Windfield)

[HURAKAN]

[HURAKAN]

THE AREA OF CONVECTION LOCATED NEAR 10.6N 128.4E,
APPROXIMATELY 395 NM EAST-SOUTHEAST OF MANILA, PHILIPPINES, HAS
REMAINED QUASI-STATIONARY OVER THE PAST SIX HOURS. RECENT ANIMATED
METSAT IMAGERY SHOWS DEEP CONVECTION DEVELOPING ON THE POLEWARD SIDE
OF THE WEAK LOW LEVEL CIRCULATION CENTER (LLCC). A 020146Z AMSU-B
MICROWAVE IMAGE SUPPORTS THE ANIMATED IMAGERY, AND SHOWS BANDING
CONVECTION ON THE NORTHERN SIDE OF THE LLCC. UPPER LEVEL ANALYSIS
INDICATES THAT THE DISTURBANCE LIES BENEATH A DIVERGENT QUADRANT OF
THE SUB-TROPICAL RIDGE TO THE NORTH WHICH IS PROVIDING GOOD POLEWARD
OUTFLOW. ALTHOUGH VERTICAL WIND SHEAR IS CURRENTLY IN THE LOW TO
MODERATE RANGE, IT IS EXPECTED TO INCREASE AS THE LLCC TRACKS TO THE
NORTHWEST INTO A REGION OF STRONG NORTHEASTERLY FLOW ASSOCIATED WITH
A COLD SURGE. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15
TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1008
MB. DUE TO THE INCREASING VERTICAL WIND SHEAR, CLOSE PROXIMITY TO
LAND AND THE EXPECTED INFLUENCE OF COLDER NORTHEASTLY FLOW, THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS REMAINS POOR.

[HURAKAN]

[Crostorm]

Looking better

[Crostorm]

TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 10.6N
128.4E WAS RE-LOCATED NEAR 8.2N 127.8E, APPROXIMATELY 555 NM
SOUTHEAST OF MANILA, PHILIPPINES. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY SHOWS AN EXPOSED, BROAD LOW-LEVEL CIRCULATION CENTER (LLCC)
WITH LITTLE ASSOCIATED DEEP CONVECTION OR DEEP CONVECTIVE BANDING.
THE LLCC REMAINS EMBEDDED WITHIN THE WEAK MONSOON TROUGH (AND QUASI-
STATIONARY) AND IS LOCATED SOUTH OF WIDESPREAD, PERSISTENT DEEP
CONVECTION FUELED BY STRONG DIFFLUENCE ALOFT AND LOW-LEVEL
CONVERGENCE OF STRONG NORTHERLY FLOW WITH EASTERLY FLOW. RECENT
SCATTEROMETER DATA SUPPORTS THIS DEPICTION WITH 10-15 KNOT UNFLAGGED
WINDS ASSOCIATED WITH THE LLCC. RECENT MICROWAVE IMAGERY ALSO FAILS
TO INDICATE ANY SIGNIFICANT CONSOLIDATION AND SHOWS THE LINEAR
NATURE OF THE CONVECTION FORMING ALONG THE CONVERGENT ASYMPTOTE
NORTH OF THE MONSOON TROUGH AXIS. UPPER AIR DATA FROM PTRO DEPICTS A
SUBSIDENCE INVERSION AT 800 MB WITH RELATIVELY DRY, STABLE AIR ABOVE.
SURFACE DATA FROM KOROR, HINATUAN, DAVAO AND VRXK4 INDICATE WEAK
WINDS AND SLP NEAR 1008 MB. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1008 MB. BASED ON THE MARGINAL ENVIRONMENT, THE POTENTIAL
FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE
NEXT 24 HOURS REMAINS POOR.

[Chacor]

PAGASA has named this "Auring".

[HURAKAN]

03/1430 UTC 9.0N 127.2E T2.0/2.0 99W -- West Pacific

[HURAKAN]

[Cookie]

strange this ain't on weather underground yet?

[Chacor]

strange this ain't on weather underground yet?

They use unofficial JTWC data. The WPac is warned on primarily by the Japan Met Agency.

[HURAKAN]

Shear 2009.

[HURAKAN]

THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 8.2N 127.8E
IS NOW LOCATED NEAR 9.0N 127.3E, APPROXIMATELY 500 NM SOUTHEAST OF
MANILA, PHILIPPINES. RECENT ANIMATED INFRARED AND WATER VAPOR
SATELLITE IMAGERY SHOWS DEEP CONVECTION PERSISTING ALONG A
CONVERGENT BAND ON THE NORTHWESTERN PERIPHERY OF A DEVELOPING LOW
LEVEL CIRCULATION CENTER (LLCC) EVIDENT IN A 031648Z AMSR-E PASS.
THE LLCC LIES SOUTH OF AN UPPER LEVEL RIDGE AXIS, IN AN AREA OF
MODERATE TO STRONG SOUTHEASTERLY VERTICAL WIND SHEAR AND VERY STRONG
WESTWARD AND POLEWARD DIFFLUENCE ALOFT. PERSISTENT DEEP CONVECTION
FUELED BY THIS UPPER LEVEL DIFFLUENCE HAS ENABLED THE LLCC TO
CONSOLIDATE DESPITE THE UNFAVORABLY STRONG VERTICAL WIND SHEAR.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. BASED ON
IMPROVING LOW LEVEL STRUCTURE, THE POTENTIAL FOR THE DEVELOPMENT OF
A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED
TO FAIR.

[Crostorm]

(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 9.0N 127.3E
IS NOW LOCATED NEAR 9.5N 128.9E, APPROXIMATELY 565 NM EAST-SOUTHEAST
OF MANILA, PHILIPPINES. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
AND A 040100Z AMSU IMAGE DEPICT A PARTIALLY-EXPOSED, WELL-DEFINED
LOW-LEVEL CIRCULATION CENTER (LLCC) WITH AN ISOLATED BURST OF DEEP
CONVECTION OVER THE NORTHWEST QUADRANT AND THE BULK OF DEEP CONVECT-
ION STILL NORTH OF THE SYSTEM. OVER THE PAST 12 HOURS, THERE HAS
BEEN A SLIGHT IMPROVEMENT IN THE ENVIRONMENT WITH VERTICAL WIND
SHEAR DECREASING AND NOW WEAK (10-15 KNOTS) PLUS CONTINUED STRONG
UPPER-LEVEL DIFFLUENCE. HOWEVER, THE LLCC STILL REMAINS SOUTH OF
THE UPPER-LEVEL RIDGE AXIS AND UNDER MODERATE EASTERLY FLOW WITH
THE LATEST UPPER-AIR SOUNDING FROM KOROR SHOWING RELATIVELY DRY
AIR ABOVE 800 MB WHICH IS INHIBITING SIGNIFICANT CONSOLIDATION AND
LEADING TO SLOW DEVELOPMENT. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1006 MB. BASED ON THE IMPROVED LOW LEVEL
STRUCTURE AND SLIGHTLY IMPROVED ENVIRONMENT, THE POTENTIAL FOR
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT
24 HOURS REMAINS FAIR.

[RL3AO]

I take it this was tagged 99W before the new year?

[Crostorm]

TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 9.5N 128.9E
IS NOW LOCATED NEAR 12.5N 128.6E, APPROXIMATELY 465 NM EAST-SOUTHEAST
OF MANILA, PHILIPPINES. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
DEPICTS A SLOWLY CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC)
WITH A BURST OF DEEP CONVECTION OVER THE NORTH QUADRANT. A 042329Z
SSMIS 37 GHZ IMAGE SHOWS A BROAD LLCC WITH WEAK CONVECTIVE BANDING
WRAPPING INTO THE WEST QUADRANT. THE BULK OF THE DEEP CONVECTION
CONTINUES TO FORM ALONG THE CONVERGENT LINE SITUATED ALONG 14-15N.
A 042151Z QUIKSCAT IMAGE SHOWED AN ELONGATED LLCC WITH 15-20 KNOT
UNFLAGGED WINDS. MULTIPLE SHIP OBSERVATIONS WITHIN 130 NM OF THE
CENTER INDICATED SLP NEAR 1008 MB AND WINDS RANGING FROM 16-29
KNOTS. WINDS FROM THE 2 CLOSEST SHIPS (VNVF, PCDE) WERE 16-22
KNOTS SUPPORTING THE RECENT QUIKSCAT AND ONDB (130 NM WSW) REPORTED
340/29 KNOTS AND APPEARS TO BE ASSOCIATED WITH A WESTERN BAND OF
CONVECTION. UPPER-LEVEL ANALYSIS ALSO INDICATES AN IMPROVED
ENVIRONMENT WITH WEAK VERTICAL WIND SHEAR AND A DEVELOPING ANTI-
CYCLONE OVER THE CENTER WITH GOOD POLEWARD OUTFLOW. THE PRIMARY
HINDRANCE CONTINUES TO BE THE LACK OF CONVECTIVE BANDING AND THE
NON-PERSISTENT DEEP CONVECTION POSSIBLY DUE TO DRY AIR ABOVE
800 MB AS SEEN IN THE LATEST KOROR SOUNDING. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 17 TO 22 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 FAIR.

[HURAKAN]

In bad shape.

[hcane27]

[Crostorm]

(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 12.5N
128.2E, IS NOW LOCATED NEAR 12.1N 126.2E, APPROXIMATELY 330 NM EAST-
SOUTHEAST OF MANILA, PHILIPPINES. ANIMATED WATER VAPOR SATELLITE
IMAGERY DEPICTS A GREATLY REDUCED AREA OF CONVECTION NORTHEAST OF
THE LOW-LEVEL CIRCULATION CENTER (LLCC). THIS REMNANT CONVECTION IS
BEING SEVERELY SHEARED TO THE NORTHEAST BY STRONG WINDS ASSOCIATED
WITH THE SUBBTROPICAL JET. A 052125Z QUIKSCAT PASS AND A 060056Z
AMSU-B MICROWAVE IMAGE SHOW A BROAD AND POORLY-DEFINED LLCC. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007 MB. WITH THE SUSTAINED
STRONG VERTICAL WIND SHEAR ALOFT AND THE LLCC BECOMING MORE
DISORGANIZED, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT
TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS POOR.