348
WTPZ42 KNHC 180856
TCDEP2
TROPICAL STORM NORMA DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL EP172023
300 AM MDT WED OCT 18 2023
SATELLITE IMAGERY SHOWS NORMA QUICKLY BECOMING BETTER ORGANIZED. THE
CENTRAL DENSE OVERCAST IS CONTINUING TO EXPAND, WITH COLD CLOUD TOP
TEMPERATURES OF LESS THAN -90 DEGREES C. A RECENT ASCAT PASS OVER
THE EASTERN EDGE OF THE STORM SUGGESTED THAT THE LOW-LEVEL CENTER
WAS NEAR THE SOUTHEASTERN SIDE OF THE DEEPEST CONVECTION. THE
INITIAL INTENSITY IS SET AT 55 KT, IN AGREEMENT WITH THE LATEST
SUBJECTIVE AND OBJECTIVE DVORAK CLASSIFICATIONS FROM TAFB AND
UW-CIMSS ADT, RESPECTIVELY.
NORMA APPEARS TO BE GRADUALLY TURNING, AND THE LATEST MOTION IS
ESTIMATED TO BE 320/6 KT. A WEAK RIDGE OVER MEXICO IS EXPECTED TO
STEER THE STORM NORTH-NORTHWESTWARD TO NORTHWARD FOR ABOUT 3 DAYS.
THERE IS STILL SIGNIFICANT UNCERTAINTY IN THE TRACK PREDICTION LATER
IN THE FORECAST PERIOD, WHICH IS LIKELY RELATED TO THE ANTICIPATED
VORTEX DEPTH. GLOBAL MODELS THAT SHOW A WEAKER CYCLONE, SUCH AS THE
ECMWF, TURN THE SYSTEM WESTWARD PRIOR TO THE BAJA CALIFORNIA
PENINSULA. MODEL GUIDANCE WITH A STRONGER, DEEPER CIRCULATION TEND
TO BRING THE STORM FARTHER NORTH AND TURN IT EASTWARD BY THE END OF
THE FORECAST PERIOD. THE UPDATED OFFICIAL TRACK FORECAST IS VERY
SIMILAR TO THE PREVIOUS PREDICTION AND IS CLOSE TO THE SIMPLE MODEL
CONSENSUS AID, TVCE. HOWEVER, THERE IS LOW CONFIDENCE IN THIS
FORECAST GIVEN THE SPREAD IN THE MODEL TRACKS.
ENVIRONMENTAL AND OCEANIC CONDITIONS ARE LIKELY TO REMAIN CONDUCIVE
FOR ADDITIONAL STRENGTHENING THROUGH THE NEXT DAY OR SO.
STATISTICAL INDICES PREDICTING THE PROBABILITY OF RAPID
INTENSIFICATION, SUCH AS SHIPS-RI AND DTOPS, SUGGEST A VERY HIGH
LIKELIHOOD OF RAPID STRENGTHENING WITHIN 24 HOURS. THE LATEST NHC
INTENSITY FORECAST EXPLICITLY SHOWS RAPID INTENSIFICATION, WITH A
PEAK OF 100 KT BY 36 H. BY DAY 2, GLOBAL MODEL GUIDANCE SHOWS THAT
THE DEEP-LAYER VERTICAL WIND SHEAR SHOULD INCREASE OVER THE STORM
AND LIKELY INDUCE A GRADUAL WEAKENING TREND THROUGH THE REMAINDER OF
THE FORECAST PERIOD. THE OFFICIAL FORECAST REMAINS NEAR OR ABOVE
THE INTENSITY MODEL CONSENSUS AIDS.
FORECAST POSITIONS AND MAX WINDS
INIT 18/0900Z 14.2N 107.9W 55 KT 65 MPH
12H 18/1800Z 15.0N 108.1W 70 KT 80 MPH
24H 19/0600Z 16.2N 108.3W 85 KT 100 MPH
36H 19/1800Z 17.0N 108.5W 100 KT 115 MPH
48H 20/0600Z 17.9N 108.9W 95 KT 110 MPH
60H 20/1800Z 18.9N 109.4W 90 KT 105 MPH
72H 21/0600Z 20.0N 109.8W 85 KT 100 MPH
96H 22/0600Z 22.1N 110.1W 80 KT 90 MPH
120H 23/0600Z 22.9N 109.4W 75 KT 85 MPH
FORECASTER BUCCI
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