Advisories

WDPN33 PGTW 232100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 19W (NINETEEN) 
WARNING NR 006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.0N 136.5E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 286 NM NORTH-NORTHWEST OF YAP
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED SHORTWAVE INFRARED (SWIR) SATELLITE IMAGERY DEPICTS A COMPACT 
AND FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). DEEP CONVECTION 
HAS REMAINED DISPLACED WEST OF THE LLCC OVERNIGHT DUE TO PERSISTENT 
MODERATE TO HIGH NORTHEASTERLY SHEAR. A 231633Z AMSR2 COLOR-ENHANCED 
89GHZ IMAGE REVEALED THE EXPOSED LLCC EAST OF A SMALL POCKET OF DEEP 
CONVECTION WITH AN EMBEDDED MID-LEVEL MESOVORTEX. THE INITIAL POSITION 
IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLCC IN THE 
SWIR. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED 
ON A BLEND OF THE OBJECTIVE AND SUBJECTIVE INTENSITY ESTIMATES NOTED 
BELOW. ENVIRONMENTAL CONDITIONS ARE ASSESSED AS UNFAVORABLE, WITH 
MODERATE TO HIGH NORTHEASTERLY VERTICAL WIND SHEAR AND DRY MID-LEVEL 
AIR ALONG THE EASTERN FLANK OFFSETTING THE OTHERWISE FAVORABLE OCEANIC 
CONDITIONS AND SUPPORTIVE UPPER-LEVEL OUTFLOW.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: NORTHWESTERN FLANK OF A LOW- TO
MID-LEVEL NEAR EQUATORIAL RIDGE (NER) TO THE SOUTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.5 - 35 KTS
   CIMSS SATCON: 35 KTS AT 231840Z
   CIMSS ADT: 33 KTS AT 231800Z
   CIMSS AIDT: 32 KTS AT 231800Z
   CIMSS D-MINT: 27 KTS AT 231648Z
   CIMSS D-PRINT: 29 KTS AT 231800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TROPICAL DEPRESSION (TD) 19W (NINETEEN) HAS TAKEN 
A BIT OF A SLOW NORTHWARD JOG OVER THE PAST SIX HOURS, LIKELY DUE TO 
AN ABORTED ATTEMPT AT VORTEX ALIGNMENT WITH THE MID-LEVEL MESOVORTEX 
EMBEDDED IN THE CONVECTION TO THE WEST. SINCE THE 1800Z ANALYSIS, THE 
EXPOSED LLCC APPEARS TO HAVE RESUMED A NORTHEASTWARD TRACK INTO THE 
CLEAR, RELATIVELY DRY AIR EAST OF THE CONVECTION WHICH CONTINUES TO 
SLIDE WESTWARD UNDER THE MODERATE SHEAR CONDITIONS. NOW HAVING RESUMED 
COURSE, THE SYSTEM IS FORECAST TO CONTINUE TRACK IN A GRACEFUL ARC, 
TURNING NORTHWARD BY TAU 12 AS IT REACHES THE NORTHERN EDGE OF THE NER 
AND THE STEERING IS PICKED UP BY THE STR FAR TO THE NORTHEAST. BY TAU 
36, THE SYSTEM TURNS NORTHWESTWARD, FOLLOWING IN THE WAKE OF TY 17W AS 
IT BEGINS BINARY INTERACTION WITH 17W. REGARDING INTENSITY, THE SYSTEM 
IS HIGHLY UNLIKELY TO BE ABLE TO INTENSIFY IN THE FACE OF PERSISTENT 
SHEAR, WHICH IS ONLY EXPECTED TO INCREASE. FURTHER INFLUXES OF DRY AIR
WILL ADD INSULT TO INJURY AND TD 19W WILL CONTINUE TO WEAKEN THROUGH 
THE FORECAST PERIOD BEFORE DISSIPATING NO LATER THAN TAU 48. 

MODEL DISCUSSION: TRACK GUIDANCE IS IN GOOD AGREEMENT WITH MINIMAL
CROSS-TRACK SPREAD THROUGH THE FORECAST PERIOD. DISCOUNTING THE UKMET 
ENSEMBLE MEAN WHICH TURNS THE SYSTEM WEST AT TAU 24, ALONG-TRACK 
SPREAD INCREASES TO 225NM, BETWEEN THE FAST GFS AND THE SLOW NAVGEM, 
BY TAU 48. THE JTWC FORECAST IS PLACED NEAR THE CONSENSUS MEAN AND THE 
EXPERIMENTAL GOOGLE DEEPMIND TRACKER WITH HIGH CONFIDENCE. INTENSITY 
GUIDANCE IS ALSO IN GOOD AGREEMENT THAT THE SYSTEM WILL STEADILY 
WEAKEN THROUGH DISSIPATION BETWEEN TAU 24 AND TAU 48. THE ONLY 
EXCEPTION IS CTCX, WHICH DEPICTS A REINTENSIFICATION AFTER TAU 24. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: MEDIUM//
NNNN