200
WTNT42 KNHC 131453
TCDAT2
TROPICAL STORM LORENZO DISCUSSION NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122025
1100 AM AST MON OCT 13 2025
LORENZO HAS MAINTAINED A LARGE AREA OF CONVECTION WITH COLD CLOUD
TOPS, ALTHOUGH THE LATEST GOES-19 1-MINUTE VISIBLE SATELLITE IMAGES
SUGGEST THAT THE LOW-LEVEL CENTER IS NEAR THE SOUTHWESTERN EDGE OF
THIS CONVECTION, WHICH MAKES SENSE DUE TO THE STRONG SOUTHWESTERLY
WIND SHEAR OVER THE CYCLONE. OVERALL, LORENZO'S STRUCTURE HASN'T
CHANGED MUCH OVER THE PAST 6 HOURS. HOWEVER, A TIMELY RECENT ASCAT
PASS SHOWS A LARGE AREA OF 40-45 KT WINDS MAINLY IN THE NORTHEAST
QUADRANT, SO THE INITIAL INTENSITY IS INCREASED TO 45 KT, WHICH IS
SLIGHTLY ABOVE THE LATEST OBJECTIVE CURRENT SATELLITE INTENSITY
ESTIMATES FROM UW-CIMSS.
THE INITIAL MOTION ESTIMATE IS NORTHWESTWARD, OR 310 DEGREES AT 14
KT. LORENZO IS NEAR THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL HIGH
CENTERED NEAR THE CABO VERDE ISLANDS. FARTHER NORTHWEST, A MID- TO
UPPER-LEVEL TROUGH IS ACTING TO ERODE THE SUBTROPICAL RIDGE. THIS
TROUGH IS EXPECTED TO FRACTURE AND SHIFT TO THE SOUTHWEST OF THE
SYSTEM, AND LORENZO SHOULD TURN NORTHWARD ON TUESDAY BETWEEN THIS
FEATURE AND THE ERODED MID-LEVEL RIDGE CENTERED OVER THE CABO VERDE
ISLANDS. LORENZO IS FORECAST TO RECURVE NORTHEASTWARD ON WEDNESDAY
AS THE CYCLONE COMES UNDER THE INFLUENCE OF BROAD-SCALE MID-LATITUDE
WESTERLY FLOW. IF LORENZO IS STILL ALIVE BY FRIDAY, IT COULD
APPROACH A WEAKNESS IN STEERING FLOW, WITH MID- TO UPPER-LEVEL
RIDGING POSSIBLY CENTERED TO THE NORTH OR NORTHEAST OF THE CYCLONE,
SO THE TRACK FORECAST SHOWS A SLOWDOWN WITH A TURN TO THE EAST IN
4-5 DAYS. THE TRACK GUIDANCE IS IN GOOD AGREEMENT THROUGH THE 72
HOUR POINT, BUT SPREAD INCREASES SIGNIFICANTLY AFTER THAT TIME. THE
NEW NHC TRACK FORECAST IS SLIGHTLY WEST OF THE PREVIOUS NHC
PREDICTION THROUGH HOUR 60, AND LIES CLOSE TO THE HFIP CORRECTED
CONSENSUS (HCCA) DURING THAT TIME PERIOD. AT DAY 5, THE NEW NHC
FORECAST IS SOUTH OF THE PREVIOUS PREDICTION.
LORENZO CONTINUES TO EXPERIENCE ABOUT 25 KT OF SOUTHWESTERLY WIND
SHEAR, ALTHOUGH THE SHEAR IS FORECAST TO DECREASE SIGNIFICANTLY
LATER TODAY, AND RELATIVELY LIGHT SHEAR IS ANTICIPATED FROM TONIGHT
THROUGH THURSDAY. ORDINARILY, THIS WOULD LEAD TO STRENGTHENING
GIVEN THE SUFFICENTLY WARM 27-28 C OCEAN TEMPERATURES, BUT AT THE
SAME TIME, ENVIRONMENTAL MID-LEVEL RELATIVELY HUMIDITY IS ALSO
EXPECTED TO DECREASE SUBSTANTIALLY AS THE STORM INTERACTS WITH THE
UPPER-LEVEL TROUGH AHEAD OF IT. THIS TROUGH COULD ALSO STILL
PRODUCE SOME RESIDUAL MID-LEVEL SHEAR UNDERCUTTING THE OUTFLOW
LAYER. MOST OF THE INTENSITY GUIDANCE IS NOT THAT ENTHUSIASTIC
ABOUT LORENZO'S PROSPECTS, BUT THERE ARE A COUPLE OF ECMWF ENSEMBLE
MEMBERS AND A HANDFUL OF GOOGLE DEEPMIND ENSEMBLE MEMBERS THAT MAKE
LORENZO A HURRICANE. THE NHC INTENSITY FORECAST IS UNCHANGED FROM
THE PREVIOUS ADVISORY OTHER THAN THE SLIGHTLY STRONGER INITIAL
INTENSITY, AND IS NEAR THE HIGH END OF THE INTENSITY GUIDANCE SUITE,
SHOWING LITTLE CHANGE IN STRENGTH IN THE SHORT-TERM, AND THEN
GRADUAL INTENSIFICATION AFTERWARDS. THE NHC INTENSITY FORECAST IS
STILL GENERALLY HIGHER THAN THE HCCA, HAFS, AND THE INTENSITY
CONSENSUS. THERE IS SOME POSSIBILITY THAT THE AFOREMENTIONED DRY
AIR COULD CAUSE LORENZO TO DISSIPATE BEFORE THE END OF THE 5-DAY
PERIOD, AS SUGGESTED BY SOME OF THE GLOBAL AND HURRICANE REGIONAL
MODELS, BUT THE NHC FORECAST MAINTAINS IT AS A TROPICAL STORM.
FORECAST POSITIONS AND MAX WINDS
INIT 13/1500Z 14.8N 41.2W 45 KT 50 MPH
12H 14/0000Z 15.6N 42.7W 45 KT 50 MPH
24H 14/1200Z 17.2N 44.1W 45 KT 50 MPH
36H 15/0000Z 19.2N 44.9W 45 KT 50 MPH
48H 15/1200Z 21.4N 44.9W 50 KT 60 MPH
60H 16/0000Z 23.9N 43.5W 55 KT 65 MPH
72H 16/1200Z 26.7N 41.2W 60 KT 70 MPH
96H 17/1200Z 31.4N 34.4W 55 KT 65 MPH
120H 18/1200Z 31.8N 29.8W 45 KT 50 MPH
FORECASTER HAGEN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page