WDPN31 PGTW 190300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 23W (CIMARON) WARNING 
NR 06//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 23W (CIMARON), LOCATED APPROXIMATELY 384 NM EAST OF 
SAIPAN, HAS TRACKED WESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. 
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE ON THE PARTIALLY 
EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) IN MULTISPECTRAL 
SATELLITE IMAGERY. THE CURRENT INTENSITY IS ASSESSED AT 40 KNOTS 
BASED ON A 182302Z ASCAT PASS THAT SHOWS 40 KT WINDS TO THE EAST OF 
THE CENTER. WARM SEA SURFACE TEMPERATURES (29-30 C) AND ROBUST 
EQUATORWARD OUTFLOW HAVE ENABLED 23W TO MAINTAIN ITS INTENSITY, 
ALTHOUGH CONVECTION IS NOW BEING SHEARED AWAY FROM THE LLCC DUE TO 
THE STRONG VWS. TS 23W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY 
OF A SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. 
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 23W IS FORECAST TO TRACK NORTHWESTWARD ALONG THE WESTERN 
PERIPHERY OF THE STR THROUGH TAU 72. VWS FROM THE OUTFLOW FROM TY 
22W, LOCATED TO THE NORTHWEST, IS CURRENTLY HIGH AND IMPEDING 
SIGNIFICANT INTENSIFICATION FOR TS 23W, BUT EXPECTED TO DIMINISH AS 
TY 22W MOVES FURTHER TO THE WEST. EQUATORWARD OUTFLOW IS EXPECTED TO 
REMAIN GOOD, AND TS 23W WILL BEGIN TO TAP INTO A TUTT CELL TO ITS 
EAST, INCREASING POLEWARD OUTFLOW AND ALLOWING FOR A GRADUAL 
INTENSIFICATION TREND. NUMERICAL MODELS ARE IN GOOD AGREEMENT ON 
STORM TRACK, WITH 125 NM OF CROSS-TRACK SPREAD AT TAU 72. THE JTWC 
FORECAST TRACK IS PLACED CLOSED TO THE MULTI-MODEL CONSENSUS WITH 
HIGH CONFIDENCE THROUGH TAU 72.
   C. THE FORECAST TRACK WILL SHIFT MORE NORTHWARD BY TAU 120 AS AN 
APPROACHING MID-LATITUDE TROUGH WEAKENS THE STR NEAR THE END OF THE 
PERIOD AND ALLOWS THE CYCLONE TO BEGIN TO GRADUALLY RECURVE. NAVGEM, 
COAMPS-TC (NAVGEM), AND COAMPS-TC (GFS) DEPICT A SLOWER TURN TO THE 
NORTH-NORTHWEST, BUT NO RECURVE. NAVGEM DOES NOT PREDICT THE TROUGH 
BEING AS DEEP OR CAUSING THE STR TO RECEDE AS MUCH AS IS PORTRAYED 
IN THE OTHER MODELS. THE SPREAD IN THE TRACK GUIDANCE INCREASES TO 
580 NM BY TAU 120 DUE TO THE DIFFERENCES IN TRACK SPEED AND DEGREE 
OF RECURVATURE BETWEEN NUMERICAL MODELS. THE STORM MOTION WILL 
ACCELERATE AT LATER TAUS, AND 23W IS NOW FORECAST TO MAKE LANDFALL 
AFTER TAU 96. PASSAGE OVER HONSHU WILL WEAKEN THE SYSTEM, ALTHOUGH 
IT MAY TAP INTO THE PASSING MIDLATITUDE TROUGH AT THE END OF THE 
FORECAST PERIOD FOR ENHANCED OUTFLOW. THE MAXIMUM INTENSITY IS 
FORECAST TO BE 75 KTS AT TAU 96, JUST PRIOR TO LANDFALL. THE JTWC 
INTENSITY FORECAST IS HEDGED ABOVE THE INTENSITY CONSENSUS AT LATER 
TAUS, IN LINE WITH THE COAMPS-TC MESOSCALE MODEL SOLUTIONS. THE JTWC 
FORECAST TRACK IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH 
FAIR CONFIDENCE.//
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