WTPZ41 KNHC 120854 RRA

TCDEP1



TROPICAL DEPRESSION SIX-E DISCUSSION NUMBER   2

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP062017

300 AM MDT WED JUL 12 2017



THE STRUCTURE OF THE DEPRESSION HAS CHANGED LITTLE DURING THE PAST

FEW HOURS, WITH THE LOW-LEVEL CENTER STILL LOCATED ON THE EASTERN

EDGE OF A CENTRAL CLUSTER OF DEEP CONVECTION.  DVORAK INTENSITY

ESTIMATES FROM TAFB AND SAB ARE T2.5/35 KT AND T1.5/25 KT, WHILE

THE OBJECTIVE ADT ESTIMATE IS T2.0/30 KT.  THE INITIAL INTENSITY

THEREFORE REMAINS 30 KT.



LOW- TO MID-LEVEL HIGH PRESSURE IS CURRENTLY LOCATED NORTH OF THE

DEPRESSION NEAR THE BAJA CALIFORNIA PENINSULA, AND IT IS STEERING

THE CYCLONE WESTWARD AT 270/10 KT.  THIS RIDGING IS EXPECTED TO

STRENGTHEN AND BUILD WESTWARD THROUGH THE FORECAST PERIOD,

IMPARTING A CONTINUED WESTWARD OR EVEN SOUTH-OF-DUE-WEST MOTION ON

THE CYCLONE THROUGH DAY 5.  IN FACT, WITH THE EXCEPTION OF THE

UKMET, THE OTHER TRACK MODELS HAVE SHIFTED NOTABLY SOUTHWARD FROM

THE PREVIOUS NHC FORECAST FOR THE FIRST 72 HOURS.  THE UPDATED NHC

TRACK FORECAST HAS ALSO BEEN SHIFTED SOUTHWARD, CLOSE TO THE TVCN

MULTI-MODEL CONSENSUS, BUT IT IS NOT AS FAR SOUTH AS THE ECMWF,

HWRF, AND HCCA MODELS.  THEREFORE, IT WOULDN'T BE SURPRISING TO SEE

ADDITIONAL SOUTHWARD ADJUSTMENTS IN FUTURE FORECAST PACKAGES.



VARIOUS SHEAR ANALYSES PLACE 10-15 KT OF NORTHEASTERLY SHEAR OVER

THE DEPRESSION, AND THAT SHEAR IS LIKELY TO CONTINUE FOR ANOTHER

24-36 HOURS.  IN THE MEANTIME, THE DEPRESSION IS MOVING OVER VERY

WARM WATERS OF 28-29 DEG C, AND THE CYCLONE'S FORECAST LOW LATITUDE

SHOULD KEEP IT OVER WARM WATER FOR THE DURATION OF THE FORECAST

PERIOD.  THE GLOBAL MODELS, PARTICULARLY THE GFS AND ECMWF, SEEM TO