WTPZ44 KNHC 021454 RRA

TCDEP4



TROPICAL STORM LIDIA DISCUSSION NUMBER  16

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP142017

900 AM MDT SAT SEP 02 2017



LIDIA HAS BECOME LESS ORGANIZED SINCE THE PREVIOUS ADVISORY, WITH

SATELLITE IMAGERY SUGGESTING THAT THE LOW-LEVEL AND MID-LEVEL

CENTERS HAVE BECOME DECOUPLED.  IN ADDITION, THE COVERAGE OF DEEP

CONVECTION HAS DIMINISHED SIGNIFICANTLY, AND THERE ARE NO RECENT

OBSERVATIONS OF SUSTAINED TROPICAL-STORM-FORCE WINDS.  THE INITIAL

INTENSITY WILL BE LOWERED TO 35 KT BASED ON THE PREMISE THAT THESE

WINDS ARE STILL OCCURRING OVER THE GULF OF CALIFORNIA.  LIDIA SHOULD

CONTINUE TO WEAKEN AS THE CENTER MOVES OVER THE COLD WATERS WEST OF

THE NORTHERN BAJA CALIFORNIA PENINSULA, AND THE SYSTEM IS EXPECTED

TO DEGENERATE INTO A REMNANT LOW IN 24 H OR LESS. THE NHC FORECAST

WILL CONTINUE TO SHOW A REMNANT LOW AT 72 H, BUT AS NOTED IN THE

PREVIOUS ADVISORY IT IS UNCLEAR WHETHER THIS WILL BE LIDIA OR

ANOTHER LOW PRESSURE AREA THAT ABSORBS THE REMNANTS OF LIDIA.



THE INITIAL MOTION IS 315/10 ALONG THE SOUTH SIDE A MID-TROPOSPHERIC

HIGH CENTERED OVER THE SOUTHWESTERN UNITED STATES, AND THIS MOTION

SHOULD CONTINUE FOR THE NEXT 36 H OR SO.  AFTER THAT, A TURN TOWARD

THE WEST-NORTHWEST IS EXPECTED DUE TO INTERACTION WITH A MID- TO

UPPER-LEVEL LOW CURRENTLY SEEN IN WATER VAPOR IMAGERY WELL TO THE

WEST OF THE BAJA CALIFORNIA PENINSULA.  THE NEW FORECAST TRACK IS

AN UPDATE OF THE PREVIOUS TRACK AND LIES IN THE CENTER OF THE

TIGHTLY-CLUSTERED TRACK GUIDANCE.



DESPITE THE ONGOING AND FORECAST WEAKENING, THE HEAVY RAINFALL

THREAT WILL CONTINUE OVER NORTHWESTERN MEXICO AND THE BAJA