286
WTPZ41 KNHC 301435
TCDEP1
TROPICAL STORM ALVIN DISCUSSION NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL EP012025
800 AM MST FRI MAY 30 2025
ALVIN IS NOW MOVING INTO AN AREA OF STRONGER SOUTH TO SOUTHWESTERLY
WIND SHEAR, AND WATER VAPOR IMAGERY SHOWS THE CYCLONE MOVING INTO A
PROGRESSIVELY DRIER AIRMASS. THE CENTER IS ESTIMATED TO BE
UNDERNEATH THE SOUTHERN PORTION OF THE CONVECTION. THE CONVECTIVE
ORGANIZATION OF THE CYCLONE APPEARS TO HAVE DEGRADED SLIGHTLY OVER
THE PAST 6 HOURS. RECENT AMSR2 AND GMI MICROWAVE PASSES SHOW THAT
THE CONVECTION IN THE SOUTHERN SEMICIRCLE HAS COMPLETELY ERODED. CI
NUMBERS FROM TAFB AND SAB BOTH REMAIN AT T-3.0/45 KT, AND OBJECTIVE
INTENSITY ESTIMATES FROM UW-CIMSS ARE A BIT HIGHER. GIVEN THE LARGE
AREA OF 40-45 KT WINDS ON THE ASCAT PASS FROM 0438 UTC THIS MORNING,
45 KT IS HELD FOR THIS ADVISORY.
THE INITIAL MOTION IS ESTIMATED TO BE NORTHWEST, OR 325/9-KT.
ALVIN IS FORECAST TO TURN NORTHWARD OVER THE NEXT DAY OR SO AS IT
MOVES THROUGH A WEAKNESS IN THE SUBTROPICAL RIDGE, TOWARD THE EAST
SIDE OF A MID-LEVEL CUTOFF LOW LOCATED JUST WEST OF BAJA
CALIFORNIA. LITTLE CHANGE IS MADE TO THE PREVIOUS NHC TRACK
PREDICTION, WHICH LIES DOWN THE MIDDLE OF THE CONSENSUS MODEL
ENVELOPE.
ALVIN WILL CONTINUE MOVING INTO AN INCREASINGLY HOSTILE ENVIRONMENT
OF VERY STRONG WIND SHEAR, DRY AIR, AND SEA-SURFACE TEMPERATURES
THAT WILL DROP BELOW 26C ALONG ALVIN'S PATH IN ABOUT 12 HOURS.
THESE CONDITIONS WILL LEAD TO ALVIN LOSING ITS CONVECTION BY
SATURDAY, WHICH IS DEPICTED BY THE GFS AND ECMWF SIMULATED
SATELLITE IMAGERY. THERE ARE NO SIGNIFICANT CHANGES TO THE NHC
INTENSITY FORECAST, AND ALVIN IS FORECAST TO DEGENERATE TO A
REMNANT LOW IN ABOUT 24 HOURS, WITH DISSIPATION IN A LITTLE OVER 2
DAYS.
FORECAST POSITIONS AND MAX WINDS
INIT 30/1500Z 17.4N 108.8W 45 KT 50 MPH
12H 31/0000Z 18.7N 109.1W 35 KT 40 MPH
24H 31/1200Z 20.3N 109.4W 30 KT 35 MPH...POST-TROP/REMNT LOW
36H 01/0000Z 21.8N 109.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 01/1200Z 23.5N 109.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
60H 02/0000Z...DISSIPATED
FORECASTER HAGEN
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