531
WTNT42 KNHC 140851
TCDAT2
TROPICAL STORM LORENZO DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122025
500 AM AST TUE OCT 14 2025
LORENZO HAS THE APPEARANCE OF A SHEARED TROPICAL CYCLONE, WITH THE
ESTIMATED CENTER EXPOSED ABOUT 30 TO 45 N MI OUTSIDE THE
NORTHWESTERN EDGE OF THE CYCLONE'S MAIN CONVECTIVE MASS. GOES-19
PROXY VIS IMAGERY SUGGESTS THAT LORENZO'S EXPOSED LOW-LEVEL CENTER
HAS BEEN MOVING FARTHER AWAY FROM THE CONVECTION TO THE NORTHWEST
OVER THE PAST SEVERAL HOURS. LORENZO IS STRUGGLING, EVEN THOUGH
SHIPS GUIDANCE AND UW-CIMSS ANALYSES INDICATE THAT THE CYCLONE HAS
REACHED A LOWER WIND SHEAR ENVIRONMENT COMPARED TO THE STRONGER
SHEAR IT WAS EXPERIENCING YESTERDAY, SINCE THE UPPER LOW TO THE WEST
OF LORENZO HAS MOVED FARTHER AWAY. THE LATEST SUBJECTIVE AND
OBJECTIVE INTENSITY ESTIMATES RANGE FROM 31-45 KT. THE INITIAL
INTENSITY WILL BE MAINTAINED AT 50 KT FOR THIS ADVISORY BASED ON THE
EARLIER EVENING ASCAT DATA, BUT IF CONVECTION DOESN'T DEVELOP CLOSER
TO THE LOW-LEVEL CENTER SOON, THEN THE WINDS COULD START TO
DECREASE.
THE INITIAL MOTION ESTIMATE IS NORTHWESTWARD, OR 310 DEGREES AT 13
KT. THE NORTHWEST MOTION SHOULD CONTINUE TODAY AS LORENZO
APPROACHES A WEAKNESS IN THE SUBTROPICAL RIDGE. A TURN TO THE NORTH
IS EXPECTED TONIGHT, WITH A NORTHEASTWARD MOTION EXPECTED WEDNESDAY
AND THURSDAY AS THE STORM MOVES AROUND THE NORTHWESTERN PERIPHERY OF
THE SUBTROPICAL RIDGE INTO THE FASTER FLOW REGIME OF THE
MID-LATITUDE WESTERLIES. THE NHC FORECAST WAS NUDGED SLIGHTLY
WESTWARD THROUGH THE FIRST 60 HOURS, AND IS VERY NEAR THE HFIP
CORRECTED CONSENSUS (HCCA) MODEL DURING THAT TIME PERIOD.
THEREAFTER, THE FORECAST IS MORE OR LESS SIMILAR TO THE PREVIOUS NHC
PREDICTION, SHOWING A PARTIAL CLOCKWISE LOOP FROM DAYS 3-5, AS
LORENZO (OR ITS REMNANTS) ROTATE SOUTHEASTWARD AND THEN
SOUTHWESTWARD AROUND THE AFOREMENTIONED SUBTROPICAL HIGH.
YESTERDAY, SOME OF THE GLOBAL AND REGIONAL MODELS LIKE THE GFS, HWRF
AND HMON, AS WELL AS SOME OF THE ECMWF AND GOOGLE DEEPMIND ENSEMBLE
MEMBERS WERE HOLDING ONTO LORENZO THROUGH THE 5-DAY PERIOD, EVEN
INDICATING SOME STRENGTHENING OVER THE NEXT FEW DAYS. HOWEVER, THE
LATEST CYCLE OF GLOBAL AND REGIONAL MODELS ALL SHOW LORENZO EITHER
DISSIPATING COMPLETELY OR BECOMING A REMNANT LOW BY HOUR 72, WITH
FEWER ECMWF AND GOOGLE DEEP MIND ENSEMBLE MEMBERS HOLDING ONTO THE
SYSTEM COMPARED TO THE PREVIOUS FEW CYCLES. IN FACT, MOST OF THE
RELIABLE MODEL GUIDANCE SHOWS A STEADY INTENSITY FOR A DAY OR SO,
FOLLOWED BY WEAKENING, AND THEN DISSIPATION IN ABOUT 3 DAYS. THE
NEW NHC INTENSITY FORECAST IS SLIGHTLY LOWER THAN THE PREVIOUS
PREDICTION, BUT WILL NOT BITE OFF YET ON THE AFOREMENTIONED MODEL
SOLUTIONS SINCE LORENZO IS FORECAST TO REMAIN IN RELATIVELY LOW
SHEAR AND WARM OCEAN TEMPERATURES FOR THE NEXT FEW DAYS. THE NHC
INTENSITY FORECAST IS AT THE HIGH END OF THE INTENSITY GUIDANCE
SUITE THROUGH HOUR 12, AND THEN IS ABOVE ALL OF THE INTENSITY MODELS
FROM HOUR 24 ONWARD. THE INTENSITY FORECAST IS LOW CONFIDENCE, AND
IT'S POSSIBLE THAT LORENZO COULD DISSIPATE SOONER THAN FORECAST.
FORECAST POSITIONS AND MAX WINDS
INIT 14/0900Z 17.3N 44.1W 50 KT 60 MPH
12H 14/1800Z 18.4N 44.8W 50 KT 60 MPH
24H 15/0600Z 20.5N 44.8W 50 KT 60 MPH
36H 15/1800Z 23.0N 43.5W 55 KT 65 MPH
48H 16/0600Z 25.5N 41.0W 55 KT 65 MPH
60H 16/1800Z 27.9N 37.4W 50 KT 60 MPH
72H 17/0600Z 29.4N 34.0W 50 KT 60 MPH
96H 18/0600Z 28.5N 30.0W 45 KT 50 MPH
120H 19/0600Z 25.9N 32.5W 40 KT 45 MPH...POST-TROPICAL
FORECASTER HAGEN
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