WDPN31 PGTW 230300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W (NORU) WARNING NR
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS
TROPICAL STORM (TS) 07W (NORU), LOCATED APPROXIMATELY 286 NM
NORTH-NORTHWEST OF MINAMI TORI SHIMA, HAS TRACKED WESTWARD AT 08
KNOTS OVER THE PAST SIX HOURS. ANIMATED HIGH RESOLUTION
MULTISPECTRAL SATELLITE IMAGERY DEPICTS A SYSTEM STRUGGLING TO
MAINTAIN STRENGTH, AND DECREASED CENTRAL CONVECTION. MULTIPLE
PULSES OF CONVECTION HAVE BROKEN OFF OF THE CORE MASS RESULTING IN
AN EVER SMALLER CONVECTIVE CORE NEAR THE LOW LEVEL CIRCULATION
CENTER (LLCC). AT THE SAME TIME THE UPPER LEVEL OUTFLOW SIGNATURE
THAT WAS VERY PROMINENT SIX HOURS AGO HAS ALL BUT DISSIPATED. THE
CURRENT POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A 222356Z
AMSU-B 89 GHZ MICROWAVE IMAGE, WHICH ALSO SHOWS THAT DEEPCONVECTION
HAS SIGNIFICANTLY WANED SINCE THE PREVIOUS DISCUSSION, WHILE
SHALLOW CONVECTIVE BANDS ARE STILL FLOWING INTO A WELL DEFINED
LLCC. THE CURRENT INTENSITY HAS BEEN REDUCED TO 45 KNOTS IN LINE
WITH SUBJECTIVE DVORAK INTENSITY ESTIMATES OF T3.0 FROM ALL
AGENCIES AND SATCON ESTIMATES OF 47 KNOTS. UPPER-LEVEL ANALYSIS
REVEALS THAT UPPER LEVEL OUTFLOW HAS SIGNIFICANTLY WEAKENED, WITH
THE UPPER-LEVEL ANTICYCLONE MOVING FURTHER AWAY TO THE SOUTHEAST,
LEAVING TS 07W WITH ONLY WEAK OUTFLOW CHANNELS. VERTICAL WIND SHEAR
(VWS) REMAINS LOW AT 5-10 KNOTS AND SEA SURFACE TEMPERATURES NEAR
30 DEG CELSIUS ARE SUPPORTIVE FOR INTENSIFICATION. TS 07W IS
DRIFTING SLOWLY WESTWARD AND HAS BASICALLY BECOME QUASI-STATIONARY
AS OF THE INITIAL POSITION TIME.
3. FORECAST REASONING.
A. NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING.
B. TS 07W HAS BECOME QUASI-STATIONARY AND IS FORECAST TO SLOWLY
MEANDER FOR THE NEXT 12 HOURS. AFTER TAU 24, THE SYSTEM WILL TURN
TOWARDS THE SOUTHEAST AND ACCELERATE UNDER THE INFLUENCE OF TWO
FACTORS. FIRST, AN EXTENSION OF THE STR TO THE NORTH WILL DEVELOP
TO THE NORTHWEST OF THE SYSTEM, TURNING IT TOWARDS THE SOUTH. ONCE
THE TURN OCCURS, THE SYSTEM WILL COME UNDER THE INFLUENCE OF THE
NER TO THE SOUTH. THIS NER, COMBINED WITH THE APPROACH AND
POTENTIAL BINARY INTERACTION WITH TS 09W OR ITS REMNANTS WILL LEAD
THE SYSTEM TO TRACK TOWARDS THE EAST-SOUTHEAST THROUGH TAU 48. BY
TAU 72, TS 07W WILL BEGIN TRACKING NORTHWESTWARDS AS IT INTERACTS
WITH TS 09W. TS 07W IS FORECAST TO MAINTAIN ITS CURRENT INTENSITY
FOR THE NEXT 12 HOURS, THEREAFTER STEADILY INTENSIFYING AS THE
SYSTEM TAPS INTO AN EASTWARD OUTFLOW CHANNEL PROVIDED BY AN UPPER
LEVEL LOW CENTERED TO THE NORTHEAST OF THE SYSTEM AND PEAKING AT
TAU 48. DYNAMIC GUIDANCE IS IN SURPRISINGLY GOOD AGREEMENT IN
SUPPORTING THE FORECAST THROUGH TAU 72 WITH HWRF THE SOLE OUTLIER
KEEPING THE SYSTEM IN A MUCH TIGHTER LOOP.
C. IN THE EXTENDED FORECAST PERIOD, TS 09W WILL APPROACH WITHIN
200 NM BY TAU 72 AND THE TWO SYSTEMS SHOULD BE FULLY CAPTURED IN A
BINARY INTERACTION, THOUGH TS 09W WILL HAVE DISSIPATED BY TAU 72
AND SO THE ENCOUNTER WILL BE BRIEF. TS 07W IS STILL FORECAST TO
TRACK IN A CYCLONIC LOOP UNDER A WEAK STEERING ENVIRONMENT THROUGH
TAU 96. BY TAU 120, A STR BECOMES FIRMLY ENTRENCHED OVER SOUTHERN
JAPAN, AND WILL RESULT IN A TURN BACK TOWARDS THE SOUTHWEST BY TAU
120. THE UPPER LEVEL ENVIRONMENT BECOMES LESS FAVORABLE AFTER TAU
72 WITH NO STRONG OUTFLOW CHANNELS. ADDITIONALLY, AS THE SYSTEM
TRACKS BACK OVER WATERS PREVIOUSLY TRAVERSED, UPWELLING COOLED
WATERS WILL STARVE THE SYSTEM OF ENERGY. DUE TO THE COMPLEX
INTERACTION BETWEEN THE TWO SYSTEMS AND THE UNCERTAINTY IN THE
UPPER-LEVEL ENVIRONMENT, THERE IS LOW CONFIDENCE IN THE JTWC
FORECAST.//
NNNN
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W (NORU) WARNING NR
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS
TROPICAL STORM (TS) 07W (NORU), LOCATED APPROXIMATELY 286 NM
NORTH-NORTHWEST OF MINAMI TORI SHIMA, HAS TRACKED WESTWARD AT 08
KNOTS OVER THE PAST SIX HOURS. ANIMATED HIGH RESOLUTION
MULTISPECTRAL SATELLITE IMAGERY DEPICTS A SYSTEM STRUGGLING TO
MAINTAIN STRENGTH, AND DECREASED CENTRAL CONVECTION. MULTIPLE
PULSES OF CONVECTION HAVE BROKEN OFF OF THE CORE MASS RESULTING IN
AN EVER SMALLER CONVECTIVE CORE NEAR THE LOW LEVEL CIRCULATION
CENTER (LLCC). AT THE SAME TIME THE UPPER LEVEL OUTFLOW SIGNATURE
THAT WAS VERY PROMINENT SIX HOURS AGO HAS ALL BUT DISSIPATED. THE
CURRENT POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A 222356Z
AMSU-B 89 GHZ MICROWAVE IMAGE, WHICH ALSO SHOWS THAT DEEPCONVECTION
HAS SIGNIFICANTLY WANED SINCE THE PREVIOUS DISCUSSION, WHILE
SHALLOW CONVECTIVE BANDS ARE STILL FLOWING INTO A WELL DEFINED
LLCC. THE CURRENT INTENSITY HAS BEEN REDUCED TO 45 KNOTS IN LINE
WITH SUBJECTIVE DVORAK INTENSITY ESTIMATES OF T3.0 FROM ALL
AGENCIES AND SATCON ESTIMATES OF 47 KNOTS. UPPER-LEVEL ANALYSIS
REVEALS THAT UPPER LEVEL OUTFLOW HAS SIGNIFICANTLY WEAKENED, WITH
THE UPPER-LEVEL ANTICYCLONE MOVING FURTHER AWAY TO THE SOUTHEAST,
LEAVING TS 07W WITH ONLY WEAK OUTFLOW CHANNELS. VERTICAL WIND SHEAR
(VWS) REMAINS LOW AT 5-10 KNOTS AND SEA SURFACE TEMPERATURES NEAR
30 DEG CELSIUS ARE SUPPORTIVE FOR INTENSIFICATION. TS 07W IS
DRIFTING SLOWLY WESTWARD AND HAS BASICALLY BECOME QUASI-STATIONARY
AS OF THE INITIAL POSITION TIME.
3. FORECAST REASONING.
A. NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING.
B. TS 07W HAS BECOME QUASI-STATIONARY AND IS FORECAST TO SLOWLY
MEANDER FOR THE NEXT 12 HOURS. AFTER TAU 24, THE SYSTEM WILL TURN
TOWARDS THE SOUTHEAST AND ACCELERATE UNDER THE INFLUENCE OF TWO
FACTORS. FIRST, AN EXTENSION OF THE STR TO THE NORTH WILL DEVELOP
TO THE NORTHWEST OF THE SYSTEM, TURNING IT TOWARDS THE SOUTH. ONCE
THE TURN OCCURS, THE SYSTEM WILL COME UNDER THE INFLUENCE OF THE
NER TO THE SOUTH. THIS NER, COMBINED WITH THE APPROACH AND
POTENTIAL BINARY INTERACTION WITH TS 09W OR ITS REMNANTS WILL LEAD
THE SYSTEM TO TRACK TOWARDS THE EAST-SOUTHEAST THROUGH TAU 48. BY
TAU 72, TS 07W WILL BEGIN TRACKING NORTHWESTWARDS AS IT INTERACTS
WITH TS 09W. TS 07W IS FORECAST TO MAINTAIN ITS CURRENT INTENSITY
FOR THE NEXT 12 HOURS, THEREAFTER STEADILY INTENSIFYING AS THE
SYSTEM TAPS INTO AN EASTWARD OUTFLOW CHANNEL PROVIDED BY AN UPPER
LEVEL LOW CENTERED TO THE NORTHEAST OF THE SYSTEM AND PEAKING AT
TAU 48. DYNAMIC GUIDANCE IS IN SURPRISINGLY GOOD AGREEMENT IN
SUPPORTING THE FORECAST THROUGH TAU 72 WITH HWRF THE SOLE OUTLIER
KEEPING THE SYSTEM IN A MUCH TIGHTER LOOP.
C. IN THE EXTENDED FORECAST PERIOD, TS 09W WILL APPROACH WITHIN
200 NM BY TAU 72 AND THE TWO SYSTEMS SHOULD BE FULLY CAPTURED IN A
BINARY INTERACTION, THOUGH TS 09W WILL HAVE DISSIPATED BY TAU 72
AND SO THE ENCOUNTER WILL BE BRIEF. TS 07W IS STILL FORECAST TO
TRACK IN A CYCLONIC LOOP UNDER A WEAK STEERING ENVIRONMENT THROUGH
TAU 96. BY TAU 120, A STR BECOMES FIRMLY ENTRENCHED OVER SOUTHERN
JAPAN, AND WILL RESULT IN A TURN BACK TOWARDS THE SOUTHWEST BY TAU
120. THE UPPER LEVEL ENVIRONMENT BECOMES LESS FAVORABLE AFTER TAU
72 WITH NO STRONG OUTFLOW CHANNELS. ADDITIONALLY, AS THE SYSTEM
TRACKS BACK OVER WATERS PREVIOUSLY TRAVERSED, UPWELLING COOLED
WATERS WILL STARVE THE SYSTEM OF ENERGY. DUE TO THE COMPLEX
INTERACTION BETWEEN THE TWO SYSTEMS AND THE UNCERTAINTY IN THE
UPPER-LEVEL ENVIRONMENT, THERE IS LOW CONFIDENCE IN THE JTWC
FORECAST.//
NNNN
Sure, it's a small system, but I think JTWC went a little too extreme there.
