962
WTPZ45 KNHC 241435
TCDEP5
TROPICAL STORM JOHN DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL EP102024
900 AM CST TUE SEP 24 2024
JOHN HAS BEEN RAPIDLY WEAKENING SINCE IT MOVED INLAND LAST NIGHT,
AND THE MAXIMUM SUSTAINED WINDS ARE NOW ESTIMATED TO BE AROUND 35
KT. THE STORM STILL HAS A WELL-DEFINED MID-LEVEL CENTER, BUT
SURFACE OBSERVATIONS SUGGEST THAT THE LOW-LEVEL CIRCULATION IS
LESS DEFINED AND COULD BE OPENING INTO A TROUGH. A STRONG BAND OF
THUNDERSTORMS TO THE EAST OF THE ESTIMATED CENTER CONTINUES TO
PRODUCE HEAVY RAINS ACROSS PORTIONS OF SOUTHERN MEXICO.
THERE IS QUITE A BIT OF UNCERTAINTY IN THE FUTURE OF JOHN. ONE
POSSIBILITY IS THAT THE STORM DISSIPATES OVER MEXICO, WITH A TROUGH
OR LOW REFORMING BACK OFFSHORE AND LINGERING IN THAT LOCATION FOR
MUCH OF THE REST OF THE WEEK. THE OTHER POSSIBILITY IS THAT JOHN
ITSELF HANGS ON AS A TROPICAL DEPRESSION OR STORM. FOR NOW, THE
OFFICIAL FORECAST GENERALLY FOLLOWS THE PREVIOUS SCENARIO AND SHOWS
JOHN WEAKENING TO A TROPICAL DEPRESSION LATER TODAY AND LINGERING
NEAR THE COAST OF SOUTHERN AND SOUTHWESTERN MEXICO UNTIL THE END OF
THE WEEK. IT IS HOPED THAT ADDITIONAL DATA AND MODEL RUNS LATER
TODAY WILL HELP PROVIDE SOME CLARITY ON THE SYSTEM'S FUTURE.
EVEN THOUGH THE FUTURE OF JOHN IS UNCERTAIN, THERE IS HIGH
CONFIDENCE THAT HEAVY RAINS WILL CONTINUE IN PORTIONS OF SOUTHERN
AND SOUTHWESTERN MEXICO DURING THE NEXT COUPLE OF DAYS. SEE THE KEY
MESSAGES BELOW FOR ADDITIONAL INFORMATION ON THAT HAZARD.
KEY MESSAGES:
1. SLOW-MOVING JOHN WILL CONTINUE TO BRING VERY HEAVY RAINFALL TO
COASTAL PORTIONS OF SOUTHERN AND SOUTHWESTERN MEXICO THROUGH THE
UPCOMING WEEK. THIS HEAVY RAINFALL WILL LIKELY CAUSE SIGNIFICANT AND
POSSIBLY CATASTROPHIC, LIFE-THREATENING FLASH FLOODING AND MUDSLIDES
TO THE MEXICAN STATES OF CHIAPAS, OAXACA, AND SOUTHEAST GUERRERO,
PARTICULARLY IN AREAS NEAR THE COAST AND ALONG THE UP-SLOPE PORTION
OF AREAS OF HIGHER TERRAIN.
2. JOHN COULD STILL PRODUCE TROPICAL STORM CONDITIONS FOR THE NEXT
COUPLE OF HOURS IN THE TROPICAL STORM WARNING AREA.
FORECAST POSITIONS AND MAX WINDS
INIT 24/1500Z 17.7N 100.5W 35 KT 40 MPH...INLAND
12H 25/0000Z 17.7N 101.1W 30 KT 35 MPH...INLAND
24H 25/1200Z 17.3N 101.1W 30 KT 35 MPH...OVER WATER
36H 26/0000Z 17.1N 100.8W 30 KT 35 MPH
48H 26/1200Z 17.4N 100.7W 25 KT 30 MPH...INLAND
60H 27/0000Z 17.7N 100.8W 25 KT 30 MPH...INLAND
72H 27/1200Z...DISSIPATED
FORECASTER CANGIALOSI
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