WTPA43 PHFO 230856 RRA

TCDCP3



TROPICAL STORM DARBY DISCUSSION NUMBER  47

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP052016

1100 PM HST FRI JUL 22 2016



DARBY'S SATELLITE PRESENTATION CONTINUES TO BE MESSY, WITH DEEP

CONVECTION NOW ON THE DECLINE AND BEGINNING TO WRAP AROUND THE

SOUTH AND SOUTHWEST QUADRANTS. CLOUD TOPS HAVE WARMED OVER THE PAST

SIX HOURS AND THE BEST OUTFLOW CONTINUES TO BE TOWARD THE

NORTHEAST, CONSISTENT WITH SOUTHWESTERLY SHEAR NEAR 10 KT DEPICTED

BY SHIPS. THE 53RD WEATHER RECONNAISSANCE SQUADRON'S WC-130J

AIRCRAFT DID A FINE JOB THIS EVENING FINDING THE CENTER OF THIS

SYSTEM, SO WE ARE CONFIDENT WE KNOW WHERE DARBY IS AND HOW IT IS

MOVING. BASED ON AIRCRAFT SFMR DATA FROM THE FIRST PASS THROUGH THE

CENTER, WE WILL KEEP AN INITIAL INTENSITY OF 50 KT FOR THIS

ADVISORY. LIKE BEFORE, THIS IS HIGHER THAN THE OBJECTIVE DVORAK

SATELLITE INTENSITY ESTIMATES FROM THE THREE SATELLITE ANALYSIS

CENTERS (HFO, JTWC AND SAB). THESE RANGE FROM 30 KT TO 45 KT.

INTERESTINGLY, AN 0630 UTC ASCAT PASS ONLY FOUND 35 KT WITHIN THE

NORTHEAST QUADRANT. THE NEXT AIRCRAFT RECONNAISSANCE MISSION INTO

DARBY WILL BE SATURDAY MORNING.



INITIAL MOTION IS 280/09 KT AS DARBY SLOWLY GAINS LATITUDE ALONG THE

SOUTHERN FLANK OF A SUBTROPICAL RIDGE. LOW PRESSURE FARTHER TO THE

NORTH IS EXPECTED TO DIG SOUTHWARD, WEAKENING THE RIDGE. THIS WILL

SIMULTANEOUSLY SLOW DARBY'S FORWARD MOTION AND DEFLECT IT TO A MORE

NORTHWESTERLY TRACK. VERTICAL WIND SHEAR WILL ALSO INCREASE,

ESPECIALLY AFTER 18 HOURS ACCORDING TO SHIPS, LIKELY LEADING TO

GRADUAL WEAKENING FROM 24 HOURS AND BEYOND. TRACK GUIDANCE HAS

CHANGED VERY LITTLE OVER THE PAST 6 TO 12 HOURS, DEPICTING A GENTLY=