WTPZ45 KNHC 122033 RRA

TCDEP5



TROPICAL DEPRESSION FIFTEEN-E DISCUSSION NUMBER   5

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP152017

200 PM PDT TUE SEP 12 2017



THE DEPRESSION IS STRUGGLING TO MAINTAIN DEEP CONVECTION IN THE FACE

OF MODERATE TO STRONG VERTICAL SHEAR.  ALL OF THE LIMITED DEEP

CONVECTION IS DISPLACED ABOUT 60 NM WEST OF ITS CENTER. THE TAFB AND

SAB DVORAK CURRENT INTENSITY VALUES HAVE NOT CHANGED, SO THE INITIAL

INTENSITY REMAINS 30 KT.



THE DISLOCATION OF THE DEEP CONVECTION SHOULD CONTINUE, AS IT'S

BEING FORCED BY STRONG EASTERLIES DUE TO AN UPPER-LEVEL RIDGE TO

THE NORTH OF THE DEPRESSION.  MODERATE SHEAR SHOULD CONTINUE FOR THE

NEXT COUPLE OF DAYS, LIMITING THE OPPORTUNITY FOR THE DEPRESSION TO

INTENSIFY.  IN ABOUT TWO DAYS, THE DEPRESSION MAY BEGIN INTERACTING

WITH A DEVELOPING TROPICAL CYCLONE TO ITS EAST.  (THIS NEW SYSTEM

IS CURRENTLY IN THE TROPICAL WEATHER OUTLOOK WITH A HIGH CHANCE OF

FORMATION WITHIN THE NEXT FIVE DAYS.)  ONE PLAUSIBLE SCENARIO IS FOR

THE DEPRESSION TO BE ABSORBED BY THE NEW TROPICAL CYCLONE.  THE

OFFICIAL INTENSITY FORECAST INSTEAD SHOWS GRADUAL WEAKENING AS THE

DEPRESSION TRACKS SLOWLY WESTWARD, DUE TO AN INCREASINGLY HOSTILE

UPPER-LEVEL ENVIRONMENT.  THE INTENSITY FORECAST IS THE SAME AS THE

PREVIOUS ONE AND IS BASED UPON A BLEND OF THE GLOBAL MODELS, THE

LGEM STATISTICAL SCHEME, AND THE COAMPS MESOSCALE HURRICANE MODEL.



THE DEPRESSION IS MOVING TOWARD THE WEST AT 12 KT, PRIMARILY BEING

STEERED BY THE DEEP-LAYER RIDGE TO ITS NORTH.  THE DEPRESSION SHOULD

CONTINUE MOVING IN THIS GENERAL DIRECTION AT A SLOWER RATE OF

FORWARD SPEED DURING THE NEXT COUPLE OF DAYS.  AT DAYS THREE AND