857 
 WTPA41 PHFO 080900
 TCDCP1
 
 TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER   2
 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP042015
 1100 PM HST TUE JUL 07 2015
 
 A BEVY OF MICROWAVE PASSES RECEIVED SINCE THE PREVIOUS ADVISORY... 
 INCLUDING AN AMSU-B PASS AT 0234Z AND SSMI/S PASSES AT 0308Z... 
 0321Z AND 0418Z...INDICATE THAT THE POORLY ORGANIZED CENTER OF 
 TROPICAL DEPRESSION FOUR-E WAS SLIGHTLY FARTHER NORTH THAN 
 ANTICIPATED. LATEST DVORAK POSITION ESTIMATES FROM HFO AND SAB 
 SUPPORT THIS NORTHWARD NUDGE...WHILE CURRENT INTENSITY ESTIMATES 
 RANGE FROM 2.0 TO 2.5. INFRARED IMAGERY SHOWS THAT A BANDING FEATURE 
 THAT BRIEFLY FLARED SOUTH OF THE CENTER LATE THIS AFTERNOON HAS 
 SINCE DIMINISHED...THUS THE INITIAL INTENSITY FOR THIS ADVISORY HAS 
 BEEN MAINTAINED AT 30 KT.  
 
 WITH THE SLIGHT NORTHWARD NUDGE...THE INITIAL MOTION ESTIMATE IS
 NOW 315/15 KT. ASIDE FROM THE CHANGE IN INITIAL POSITION...SHORT 
 TERM PHILOSOPHY WITH THE FORECAST TRACK AND INTENSITY OF THE CYCLONE 
 IS SIMILAR AS PREVIOUSLY DISCUSSED...WITH SOME MODIFICATIONS ON
 DAYS 4 AND 5. OVER THE NEXT 72 HOURS...THE SYSTEM IS FORECAST TO
 MOVE IN A GENERAL NORTHWEST DIRECTION...WITHIN THE FLOW PROVIDED BY
 A DEEP-LAYER RIDGE CENTERED TO THE NORTHEAST. LATEST ANALYSES
 INDICATE MODEST 10 KT SOUTHERLY SHEAR OVER THE CYCLONE...WHICH
 APPEARS TO BE ARRESTING DEVELOPMENT. STRONGER SOUTHWESTERLY SHEAR
 CURRENTLY LIES TO THE NORTHWEST OF THE CYCLONE...ASSOCIATED WITH THE
 GRADIENT BETWEEN A WELL-DEVELOPED CLOSED LOW ALOFT CENTERED
 NORTHEAST OF THE MAIN HAWAIIAN ISLANDS...AND THE RIDGE TO THE
 NORTHEAST OF THE CYCLONE. OVER THE NEXT COUPLE OF DAYS...THESE
 FEATURES ARE FORECAST TO MOVE WEST AT A SPEED SIMILAR TO THE
 FORWARD SPEED OF THE CYCLONE...MAINTAINING MODERATE SOUTH TO
 SOUTHWESTERLY SHEAR. THIS PERSISTENT SHEAR IS EXPECTED TO LEAD TO AN
 INCREASINGLY SHALLOW SYSTEM BY DAYS 4 AND 5...BUT SOUTHERLY
 STEERING FLOW SHOULD KEEP IT MOVING GENERALLY NORTHWEST. THE UPDATED 
 FORECAST TRACK ESSENTIALLY PARALLELS THE PREVIOUS THROUGH 72 
 HOURS...BUT IS FASTER AND TO THE RIGHT OF THE PREVIOUS FORECAST ON 
 DAYS 4 AND 5. THIS IS CLOSE TO THE GUIDANCE PRESENTED BY GFEX AND 
 TVCN CONSENSUS. 
 
 THE SHIPS GUIDANCE INDICATES THAT THE DEEP-LAYER VERTICAL WIND
 SHEAR IS EXPECTED TO REMAIN NEAR 10 KT WHILE THE SYSTEM IS
 OVER 26C OR GREATER SEA-SURFACE TEMPERATURES FOR THE NEXT 36 HOURS
 OR SO...WHICH SHOULD ALLOW FOR GRADUAL STRENGTHENING INTO A TROPICAL
 STORM. BY 36 TO 48 HOURS...SOUTHWESTERLY SHEAR IS FORECAST TO
 INCREASE TO NEAR 20 KT...WHICH SHOULD INDUCE A STEADY WEAKENING
 TREND...WITH SHIPS INDICATING DISSIPATION BY DAY 4. LATEST ECMWF
 GUIDANCE...HOWEVER...HAS A WEAKER SHEAR PROFILE AND MAINTAINS THE
 SYSTEM AS A TROPICAL CYCLONE THROUGH 120 HOURS. THE UPDATED
 INTENSITY FORECAST REPRESENTS A COMPROMISE...AND IS CLOSE TO THE
 IVCN CONSENSUS.
 
 
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  08/0900Z 17.3N 141.2W   30 KT  35 MPH
  12H  08/1800Z 18.1N 142.9W   35 KT  40 MPH
  24H  09/0600Z 19.3N 145.1W   40 KT  45 MPH
  36H  09/1800Z 20.3N 147.1W   40 KT  45 MPH
  48H  10/0600Z 21.6N 149.2W   40 KT  45 MPH
  72H  11/0600Z 23.3N 153.3W   35 KT  40 MPH
  96H  12/0600Z 25.1N 158.0W   25 KT  30 MPH
 120H  13/0600Z 27.1N 163.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
  
 $$
 
 FORECASTER BIRCHARD