740 
 WTPA44 PHFO 080840
 TCDCP4
 
 TROPICAL STORM JIMENA DISCUSSION NUMBER  51
 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP132015
 1100 PM HST MON SEP 07 2015
  
 A NOTCH WITHIN THE MAIN DEEP CONVECTIVE CURVED BAND PROVIDES A BIT 
 OF CONFIDENCE IN THE POSITION OF JIMENA THIS EVENING. HOWEVER AFTER 
 WATCHING THE TIGHTNESS OF THE LOW CLOUD SWIRLS WEST OF THE HIGH 
 CLOUD CANOPY IN ANIMATION...AND TAKING THE HIGHLY SHEARED 
 ENVIRONMENT INTO ACCOUNT...WE SUSPECT THE LLCC LIES WEST OF THE 
 APPARENT MID AND UPPER LEVEL CIRCULATION NOTED BY THE SATELLITE 
 CENTERS. THE POSITION FOR THIS ADVISORY LIES JUST WEST OF THE 
 DEEPEST CONVECTION AT 0600 UTC...BENEATH THE REMAINING HIGH CLOUDS. 
 IF THESE CLOUDS WERE TO THIN SUFFICIENTLY OVERNIGHT...WE MIGHT GET A 
 PEEK AT AN EXPOSED LLCC. A VERY LATE 0503 UTC SSMIS PASS ADDS 
 CREDENCE TO THIS POSSIBILITY. SUBJECTIVE DVORAK SATELLITE INTENSITY 
 ESTIMATES WERE ALL 2.5...35 KT...FROM THE SATELLITE CENTERS. 
 UW-CIMSS ADT WAS ALSO 35 KT. WHILE IT WAS TEMPTING TO FOLLOW SUIT 
 AND WEAKEN JIMENA TO 35 KT...THE NEW BURST OF CONVECTION ALONG THE 
 CURVED BAND ACROSS THE NORTHEAST FLANK PROMPTS US TO MAINTAIN 40 KT 
 AS THE INITIAL INTENSITY FOR THIS ADVISORY. 
 
 OUR ASSUMPTION CONCERNING THE DISPLACEMENT OF THE MID AND UPPER 
 LEVEL CIRCULATION CENTER TO THE EAST OF THE LLCC WAS PROBABLY ALSO 
 TRUE SIX HOURS AGO. FORTUNATELY...THE 12 HOUR MOTION WAS 290/06 KT 
 AND WE WILL USE THIS AS INITIAL MOTION AS WELL. JIMENA REMAINS IN A 
 HOSTILE WEST TO SOUTHWEST SHEAR ENVIRONMENT...RANGING FROM 20 KT 
 FROM SHIPS TO 30 KT FROM UW-CIMSS. THIS IS FORECAST TO INCREASE TO 
 OVER 40 KT IN 48 HOURS...ACCORDING TO SHIPS...SO IT IS DIFFICULT TO 
 SEE HOW THIS SYSTEM COULD REMAIN INTACT THROUGH A FIVE DAY FORECAST 
 TRACK. NEVERTHELESS...THIS SEEMS TO BE THE SEASON FOR STUBBORNLY 
 RESILIENT STORMS. TRACK GUIDANCE SHIFTED A BIT TO THE WEST...BUT NO 
 FARTHER SOUTH...LIKELY ACCOUNTING FOR AN INCREASE IN FORECAST 
 FORWARD SPEED AS JIMENA DEVOLVES TO A LOW-LEVEL STEERED SYSTEM. THE 
 FORECAST TRACK WAS ADJUSTED A BIT TO THE NORTH FROM THE PREVIOUS ONE 
 TO ACCOUNT FOR INITIAL MOTION...BUT FOLLOWS THE PREVIOUS TRACK ALONG 
 THE SHAPE OF CONSENSUS GUIDANCE AFTERWARDS. WE MAY HAVE TO INCREASE 
 FORWARD SPEED AFTER 48 HOURS IN SUBSEQUENT ADVISORIES IF THE 
 WESTWARD GUIDANCE SHIFT PERSISTS.
 
 JIMENA WILL GRADUALLY WEAKEN THROUGH THE NEXT FIVE DAYS...BECOMING 
 AN EXTRATROPICAL LOW BY DAY 4 IN OUR FORECAST. THE FORESEEN SHEAR 
 INCREASE BY DAY TWO MAY SHORTEN THIS LIFESPAN. THIS ADVISORY WEAKENS 
 JIMENA TO A DEPRESSION BY 36 HOURS...SLIGHTLY MORE QUICKLY THAN LAST 
 TIME. WHATEVER IS LEFT OF JIMENA WILL BE DRAWN POLEWARD ALONG THE 
 EASTERN FLANK OF LOW PRESSURE DEVELOPING NORTH OF THE NORTHWESTERN 
 HAWAIIAN ISLANDS FROM DAYS THREE TO FIVE. 
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  08/0900Z 26.8N 151.7W   40 KT  45 MPH
  12H  08/1800Z 27.0N 152.8W   40 KT  45 MPH
  24H  09/0600Z 26.8N 154.3W   35 KT  40 MPH
  36H  09/1800Z 26.5N 155.8W   30 KT  35 MPH
  48H  10/0600Z 26.3N 157.4W   30 KT  35 MPH
  72H  11/0600Z 26.4N 160.4W   25 KT  30 MPH
  96H  12/0600Z 27.9N 162.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 120H  13/0600Z 30.4N 164.4W   20 KT  25 MPH...POST-TROP/REMNT LOW
  
 $$
 FORECASTER POWELL