WTPZ43 KNHC 191441 RRA

TCDEP3



TROPICAL DEPRESSION EIGHT-E DISCUSSION NUMBER   5

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP082017

800 AM PDT WED JUL 19 2017



THE CENTER OF THE DEPRESSION IS CHALLENGING TO LOCATE THIS MORNING

WITH LOTS OF DISORGANIZED CONVECTION IN THE VICINITY OF THE APPARENT

CENTER.  MICROWAVE DATA SUGGEST IT IS ON THE NORTHEAST SIDE OF THE

CONVECTIVE MASS, ALTHOUGH IT DOESN'T AGREE THAT WELL WITH THE

OVERNIGHT ASCAT DATA.  THE INITIAL POSITION TRIES TO KEEP CONTINUITY

FROM THE OVERNIGHT ADVISORY, SINCE THERE WAS A DIRECT ASCAT HIT AT

0600Z, BUT IT MAY HAVE TO BE REVISED WHEN VISIBLE IMAGERY IS

AVAILABLE.  THE INITIAL WIND SPEED IS KEPT AT 30 KT, BASED ON A

BLEND OF THE TAFB/SAB FIXES.



UNFORTUNATELY THE FORECAST OF THE DEPRESSION ISN'T ANY EASIER THAN

LOCATING IT.  SOME BINARY INTERACTION WITH THE CIRCULATION OF

TROPICAL STORM GREG IS LIKELY OVER THE NEXT FEW DAYS SINCE THE

CYCLONES SHOULD BE MOVING FAIRLY CLOSE TO ONE ANOTHER. THIS PATTERN

WOULD PROBABLY STEER THE DEPRESSION SOUTHWESTWARD, THEN

NORTHWESTWARD BY DAY 3 AS GREG PASSES TO THE NORTH AND BEGINS TO

DRAW THE DEPRESSION CLOSER TO IT.  THE SPECIFICS OF THIS

INTERACTION, HOWEVER, ARE IMPOSSIBLE TO DETERMINE AT THIS RANGE

BECAUSE IT ALSO DEPENDS ON HOW STRONG AND EXACTLY WHERE THE TWO

SYSTEMS ARE. IT IS BECOMING INCREASINGLY LIKELY THAT GREG WILL BE

THE MORE DOMINANT AND STRONGER SYSTEM, CAUSING THE DEPRESSION TO

TAKE A MORE SOUTHWARD TRACK, AND WOULD POTENTIALLY ABSORB THE

DEPRESSION IN 4-5 DAYS.  THE OFFICIAL FORECAST IS SHIFTED SOUTHWARD

IN THE SHORT-TERM TO ACCOUNT FOR THE LATEST MODEL GUIDANCE, BUT IS

FAIRLY CLOSE TO THE PREVIOUS FORECAST AT THE END OF THE PERIOD.