WDPN31 PGTW 150900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W (LAN) WARNING NR 
031//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 35.4N 134.9E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 153 NM EAST-NORTHEAST OF IWAKUNI, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS THAT TS 07W
(LAN) IS QUICKLY MARCHING OVER THE ISLAND OF HONSHU, ON ROUTE TO
THE SEA OF JAPAN. SURFACE OBSERVATION FROM TAJIMA AND TOTTORI
AIRPORT COMBINED WITH ANIMATED RADAR IMAGERY HAVE AIDED
TREMENDOUSLY IN LOCALIZING THE SYSTEM AS IT APPROACHES OPEN OCEAN
ONCE MORE. A 150425Z AMSR2 89GHZ MICROWAVE IMAGE REVEALS A
PARTIALLY EXPOSED LLCC WITH DEEP CONVECTION FLARING OVER THE WARM
WATERS OUT AHEAD OF TRACK MOTION. THE INITIAL POSITION IS PLACED
WITH MEDIUM CONFIDENCE BASED ON MSI, AMSR2 AND RADAR IMAGERY. THE
INITIAL INTENSITY OF 50 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON AVAILABLE DVORAK INTENSITY ESTIMATES GENERALLY MATCHING
CIMSS DPRINT OF 50KTS, WHICH IS ONE OF THE FEW AUTOMATED INTENSITY
ESTIMATES THAT REPORTS OVER LAND.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED FAR TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T3.0 - 45 KTS
   RCTP: T3.0 - 45 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

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

FORECAST DISCUSSION: AS WE SPEAK, TS 07W (LAN) IS ONCE AGAIN MOVING
BACK OVER OPEN OCEAN AND IS FORECAST TO PROCEED GENERALLY POLEWARD.
AFTER ENTERING THE SEA OF JAPAN, WARM WATERS AND STEADILY IMPROVING
OUTFLOW ALOFT WILL FIGHT TO OVERCOME GRADUALLY INCREASING VERTICAL
WIND SHEAR VALUES. THE RESULT OF THE BATTLE WILL ALMOST CERTAINLY
BE ANTICLIMACTIC, AS 07W STRUGGLES TO REORGANIZE AS IT IS QUICKLY
MOVED POLEWARD. AS THE GRADUAL WESTWARD SHIFT IN TRACK FORECAST
OVER THE LAST FEW DAYS WOULD INDICATE, THERE IS A CHANCE 07W MAKES
LANDFALL OVER EASTERN RUSSIA AND DISSIPATES BY TAU 72. THE CURRENT
JTWC FORECAST PHILOSOPHY HOWEVER IS ONE OF GRADUAL DECLINE THROUGH
TAU 48 DUE TO THE INCREASING SHEAR VALUES. NEAR THE 44TH PARALLEL,
THE SYSTEM WILL BEGIN TO INTERACT WITH A STRONG BAROCLINIC ZONE AS
IT FURTHER INCREASES ITS POLEWARD TRACK SPEED, THEREBY INITIATING
EXTRA-TROPICAL TRANSITION (ETT). BY TAU 120, NOW WELL INTO THE SEA
OF OKHOTSK, 07W WILL LOSE ITS LAST REMAINING TROPICAL
CHARACTERISTICS AND COMPLETE ETT.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT, WITH ALL
MEMBERS FOLLOWING THE JTWC TRACK FORECAST AND MULTI-MODEL CONSENSUS
WITH MINIMAL VARIABILITY THROUGH TAU 72. FOR THIS REASON THE JTWC
TRACK FORECAST IS PLACED WITH OVERALL MEDIUM CONFIDENCE. RELIABLE
MODEL INTENSITY GUIDANCE IS IN GOOD AGREEMENT WITH ALL MEMBERS
SHOWING GRADUAL DECLINE THROUGH TAU 24 AND AFTER THAT SHARPER
DECLINE THROUGH THE FORECAST PERIOD. FOR THIS REASON THE JTWC
INTENSITY FORECAST IS PLACED WITH OVERALL MEDIUM CONFIDENCE AS
WELL.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM//
NNNN