WTPZ45 KNHC 120231 RRA

TCDEP5



TROPICAL DEPRESSION FIFTEEN-E DISCUSSION NUMBER   2

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP152017

900 PM MDT MON SEP 11 2017



THE TROPICAL DEPRESSION REMAINS SHEARED, AND CONVECTION HAS

DECREASED SINCE THIS AFTERNOON.  THE INITIAL INTENSITY HAS BEEN HELD

AT 25 KT BASED ON A BLEND OF THE MOST RECENT TAFB AND SAB DVORAK

CLASSIFICATIONS.  LITTLE CHANGE IN INTENSITY IS FORECAST FOR THE

NEXT FEW DAYS.  THE GFS AND ECMWF BOTH INDICATE THAT THE STRONG

EASTERLY WIND SHEAR WILL NOT DECREASE FOR THE NEXT 36 TO 48 HOURS,

WHICH SHOULD PREVENT SIGNIFICANT STRENGTHENING AND COULD CAUSE THE

CYCLONE TO QUICKLY BECOME A REMNANT LOW.  AFTER THAT TIME, THE

FORECAST BECOMES MORE COMPLICATED SINCE THE DEPRESSION, OR ITS

REMNANTS, MAY INTERACT WITH ANOTHER SURFACE LOW PRESSURE SYSTEM

FORECAST TO DEVELOP OVER THE OPEN EAST PACIFIC.  AS A RESULT OF

THIS PROXIMITY,  SOME OF THE MODEL TRACKERS DEPICT STRENGTHENING

NEAR THE END OF THE FORECAST PERIOD.  BECAUSE MOST OF THE MODELS

DEPICT THE OTHER DEVELOPING LOW AS THE DOMINANT SYSTEM IN ANY

POTENTIAL INTERACTION, I AM ELECTING TO DISCOUNT THAT POSSIBILITY

FOR NOW.  THE OFFICIAL FORECAST INSTEAD SHOWS THE DEPRESSION

BECOMING A REMNANT LOW WITHIN 72 HOURS, AND DISSIPATING ENTIRELY

SOMETIME AFTER 96 H, SIMILAR TO THE PREVIOUS ADVISORY.



THE DEPRESSION IS MOVING JUST SOUTH OF DUE WEST AT 13 KT.  THE LOW-

TO MID-LEVEL COMPONENTS OF A RIDGE LOCATED TO THE NORTH SHOULD KEEP

THE CYCLONE MOVING GENERALLY WESTWARD THROUGH THE FORECAST PERIOD,

UNTIL IT DISSIPATES. THE ECMWF SOLUTION SEEMS TO BE THE MOST

REASONABLE OF THE DYNAMICAL MODELS BECAUSE IT KEEPS THE DEPRESSION