WTPZ44 KNHC 251439 RRA

TCDEP4



HURRICANE HILARY DISCUSSION NUMBER  17

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP092017

900 AM MDT TUE JUL 25 2017



SATELLITE IMAGERY SHOWS THAT DEEP, BUT SOMEWHAT ASYMMETRIC,

CONVECTION CONTINUES IN THE INNER CORE OF HILARY.  THE 1-MINUTE

VISIBLE IMAGERY FROM GOES-16 INDICATES STRONG CONVECTIVE TOWERS ARE

FIRING IN THE NORTHEASTERN EYEWALL, THEN ATTEMPTING TO ROTATE

CYCLONICALLY AROUND THE CENTER.  STILL, THE EYEWALL REMAINS OPEN IN

THE SOUTHWEST QUADRANT, AS SUGGESTED IN THE VISIBLE IMAGERY AND

SHOWN IN A RECENT 1340 UTC SSMIS MICROWAVE PASS.  INTENSITY

ESTIMATES REMAIN ABOUT THE SAME AS OVERNIGHT, SO THE INITIAL WIND

SPEED WILL STAY AT 90 KT.



HILARY IS FORECAST TO REMAIN IN A CONDUCIVE ENVIRONMENT FOR

STRENGTHENING DURING THE NEXT DAY OR SO.  HOWEVER, THE NORTHERLY

WIND SHEAR IS NOT FAR AWAY, AS EVIDENCED BY CIRRUS CLOUDS MOVING

TOWARD THE CENTER IN THE NORTHERN SEMICIRCLE, WHICH COULD CAUSE THE

HURRICANE TO LEVEL OFF IN INTENSITY.  SIMILAR TO YESTERDAY AT THIS

TIME, THE MODEL GUIDANCE HAS REALLY BACKED DOWN OFF THE PEAK

INTENSITY, WITH FEW OF THE SOLUTIONS EVEN SHOWING HILARY REACHING

100 KT.  IT WAS EASIER TO IGNORE THE MODELS YESTERDAY BECAUSE THEY

SEEMED UNREALISTIC. TODAY THE SHEAR IS APPROACHING AND SHOULD

IMPACT THE CYCLONE WITHIN 24 HOURS.  IT SEEMS BEST TO ONLY GRADUALLY

REDUCE THE INTENSITY FORECAST, SO THE LATEST NHC PREDICTION IS

ADJUSTED TOWARD THE MODEL CONSENSUS BY DAY 3, WHEN MORE SIGNIFICANT

WEAKENING IS EXPECTED DUE TO COOLER WATERS, DRIER AIR, AND

INTERACTION WITH HURRICANE IRWIN.



THE INITIAL MOTION ESTIMATE IS A LITTLE TO THE LEFT AND FASTER,