Here an interesting excerpt from NWS puerto rico.

'SYNOPTIC PATTERN ACROSS
THE TROPICAL ATLC REMAINS VERY INTERESTING TODAY...WITH WELL
ESTABLISHED MONSOON TROUGH HAVING BROKEN FREE OF AFRICAN MONSOON
GYRE...THANKS TO A LARGE BAROCLINIC LOW HAVING MOVED ACROSS THE
CAPE VERDES PAST 24-36 HOURS...AND STRONG WLYS SOUTH OF TROUGH NOW
FLOWING SW TO NE AND INTO E SIDE OF THIS BROAD AND ELONGATED LOW.
A CLUSTER OF DEEP CNVTN AND MID LEVEL CYCLONIC TURNING CAN BE SEEN
ALONG ABOUT 9N 35W THIS MORNING ON S SIDE OF THIS EVOLVING
FEATURE. WLYS S OF THE MONSOON TROUGH NOW EXTEND FROM THE MID 50S
TO THIS LARGE TROPICAL WAVE CROSSING 30W THIS MORNING. TROPICAL
WAVE APPROACHING THE LESSER ANTILLES LOOKS TO BE ALONG 53/54W ATTM
AND GAINING POSITIVE TILT WITH TIME...AS MID LEVEL JET REMAINS
ALONG 18-20N. THIS ALIGNMENT CONTINUES TO BLEED VORTICITY AND
MOISTURE TO THE AMBIENT FLOW...WITH LEADING EDGE OF RELATED
MOISTURE JUST ABOUT TO REACH 60W ATTM. GFS NOT FORECASTING THIS
AREA OF WEATHER TO REACH THE USVI UNTIL 06-12Z FRIDAY...BUT SOME
LEADING MOISTURE LIKELY TO AFFECT THE LOCAL AREA TONIGHT. AS HAS
BEEN THE CASE ACROSS THE LOCAL REGION FOR MUCH OF THE PAST 30-60
DAYS...STEERING FLOW IS FORECAST TO GUIDE MUCH OF THE MOISTURE AND
ENERGY ASSOCIATED WITH THIS APPROACHING WAVE TO THE WNW AND
NW...AND LIFT N OF PUERTO RICO...JUST BRUSHING THE VIRGIN ISLANDS.
HOWEVER...CYCLONIC TURNING SEEN IN IR IMAGERY OVERNIGHT CENTERED
ALONG 12N 52W DOES NOT APPEAR WELL INITIALIZED BY GFS...AND THIS
MAY PASS JUST SOUTH OF PR FRI NIGHT-SAT TO IMPACT THE ISLAND MUCH
MORE SIGNIFICANTLY THAN CURRENTLY SUGGESTED. AGAIN...THIS COMPLEX
TROPICAL ENVIRONMENT ACROSS THE ATLC PROVING CHALLENGING FOR THE
GLOBAL MODELS AND THE NEXT WEEK AND BEYOND SHOULD BE INTERESTING.