628
WTNT43 KNHC 290840
TCDAT3
TROPICAL STORM RINA DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL AL182023
500 AM AST FRI SEP 29 2023
RINA HAS BECOME SLIGHTLY BETTER ORGANIZED OVERNIGHT. DEEP,
PERSISTENT CONVECTION, WITH CLOUD TOP TEMPERATURES LESS THAN -80
DEGREES C, HAS MOSTLY OBSCURED THE LOW-LEVEL CIRCULATION. WHILE THE
SUBJECTIVE SATELLITE INTENSITY ESTIMATES HAVE RISEN THIS CYCLE TO
45-55 KT, THE OBJECTIVE ESTIMATES HAVE GENERALLY HELD STEADY AROUND
35 KT. THE INITIAL INTENSITY IS SET TO 40 KT TO REPRESENT A BLEND
OF THESE ESTIMATES.
THE INTENSITY FORECAST IS STILL UNUSUALLY COMPLEX AND THEREFORE,
UNCLEAR. WHILE RINA APPEARS TO BE GRADUALLY STRENGTHENING, MOST
MODELS AGREE THAT PHILIPPE, THE TROPICAL STORM TO ITS WEST, WILL
BECOME THE STRONGER STORM. AS PHILIPPE BECOMES BETTER ORGANIZED,
RINA IS EXPECTED TO BE SHEARED AND SUBSEQUENTLY WEAKEN. BY DAYS 4
AND 5, AS RINA POTENTIALLY MOVES AWAY FROM THE INFLUENCE OF
PHILIPPE, THE GFS AND ECMWF DO NOT SHOW THE ENVIRONMENTAL CONDITIONS
BECOMING ANY MORE CONDUCIVE AND CONTINUE TO WEAKEN RINA INTO A
REMNANT LOW. ONLY MINOR ADJUSTMENTS HAVE BEEN MADE TO THE LATEST
INTENSITY FORECAST.
RINA'S MOTION IS ESTIMATED TO BE NORTH-NORTHWESTWARD, OR 340/4 KT.
THE STORM IS EXPECTED TO MOVE GENERALLY WEST-NORTHWESTWARD TO
NORTHWESTWARD THROUGH DAY 3. THIS IS IN PART DUE TO A BINARY
INTERACTION WITH PHILIPPE AND A MID-LEVEL RIDGE OVER THE EASTERN
SUBTROPICAL ATLANTIC. LATER IN THE FORECAST PERIOD, RINA IS
FORECAST TO TURN NORTH-NORTHWESTWARD TO NORTHWARD IN THE FLOW
BETWEEN THE SUBTROPICAL RIDGE AND AN UPPER-LEVEL TROUGH OVER THE
WESTERN ATLANTIC. THERE IS STILL A LARGE SPREAD IN THE MODEL
SOLUTIONS AND THUS, HIGHER UNCERTAINTY IN THE TRACK FORECAST, FOR
THE LATTER PART OF THE FORECAST PERIOD. THE MODEL GUIDANCE
ENVELOPE HAS GENERALLY SHIFTED EASTWARD THIS ADVISORY CYCLE, AND
THE LATEST NHC TRACK FORECAST HAS BEEN NUDGED IN THIS DIRECTION.
THE OFFICIAL TRACK FORECAST LIES BETWEEN THE PREVIOUS PREDICTION AND
CONSENSUS AIDS, TVCN AND HCCA.
FORECAST POSITIONS AND MAX WINDS
INIT 29/0900Z 18.9N 46.6W 40 KT 45 MPH
12H 29/1800Z 19.3N 47.1W 45 KT 50 MPH
24H 30/0600Z 19.8N 48.1W 45 KT 50 MPH
36H 30/1800Z 20.4N 49.6W 45 KT 50 MPH
48H 01/0600Z 21.1N 51.0W 40 KT 45 MPH
60H 01/1800Z 22.0N 52.8W 35 KT 40 MPH
72H 02/0600Z 23.3N 54.3W 35 KT 40 MPH
96H 03/0600Z 26.0N 56.0W 30 KT 35 MPH
120H 04/0600Z 28.1N 55.6W 30 KT 35 MPH
FORECASTER BUCCI
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