265
WTPZ42 KNHC 200241
TCDEP2
HURRICANE NORMA DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL EP172023
900 PM MDT THU OCT 19 2023
THE EYE OF NORMA IS NO LONGER EVIDENT ON CONVENTIONAL GEOSTATIONARY
SATELLITE IMAGERY, BUT COULD STILL BE SEEN ON A RECENT SSMI/S
MICROWAVE PASS. DEEP CONVECTION REMAINS VERY STRONG NEAR THE
ESTIMATED CENTER WITH SOME CLOUD TOPS COLDER THAN -80 DEG C. A FEW
CONVECTIVE BANDING FEATURES ARE EVIDENT OVER THE NORTHERN PORTION
OF THE CIRCULATION, AND UPPER-LEVEL OUTFLOW IS STILL STRONG OVER
MOST SECTORS OF THE SYSTEM. THE CURRENT INTENSITY IS SET AT 105 KT
FOR THIS ADVISORY, WHICH IS A BLEND OF VARIOUS SUBJECTIVE AND
OBJECTIVE SATELLITE ESTIMATES. THIS IS IN BEST AGREEMENT WITH A
RECENT AI-BASED OBJECTIVE DVORAK ESTIMATE FROM UW-CIMSS.
FOR THE NEXT COUPLE OF DAYS, NORMA'S ENVIRONMENT WILL BE
CHARACTERIZED BY INCREASING SOUTH-SOUTHWESTERLY VERTICAL WIND
SHEAR, ASSOCIATED WITH A BROAD UPPER-LEVEL TROUGH NEAR THE BAJA
CALIFORNIA PENINSULA, ALONG WITH A DRIER MID-LEVEL AIR MASS. THESE
FACTORS SHOULD CAUSE GRADUAL WEAKENING WHILE THE SYSTEM NEARS
SOUTHERN BAJA CALIFORNIA SUR, BUT IT IS LIKELY THAT NORMA WILL STILL
BE A HURRICANE WHEN IT MOVES NEAR OR OVER THAT AREA. THE OFFICIAL
INTENSITY FORECAST IS ON THE HIGHER SIDE OF THE MODEL GUIDANCE
DURING THE EARLY PART OF THE FORECAST PERIOD, BUT CLOSE TO THE
CORRECTED MODEL CONSENSUS, HCCA AT 48 HOURS AND BEYOND.
ALTHOUGH THE CENTER FIXES ARE A LITTLE MORE UNCERTAIN THAN EARLIER
TODAY, THE INITIAL MOTION DOES NOT APPEAR TO HAVE CHANGED MUCH AND
IS AROUND 350/6 KT. OVER THE NEXT FEW DAYS, NORMA IS EXPECTED TO
MOVE BETWEEN A MID-LEVEL HIGH TO ITS EAST AND A TROUGH TO THE
NORTHWEST AND NORTH. THE TRACK GUIDANCE MODELS, ESPECIALLY THE
MORE RELIABLE ONES, HAVE COME INTO A LITTLE BETTER AGREEMENT, AND
THE NHC FORECAST TRACK IS CLOSE TO THE SIMPLE DYNAMICAL MODEL
CONSENSUS. THIS IS ALSO CLOSE TO THE PREVIOUS OFFICIAL FORECAST.
KEY MESSAGES:
1. A HURRICANE WARNING IS IN EFFECT FOR THE FAR SOUTHERN PORTION OF
THE BAJA CALIFORNIA PENINSULA, WHERE NORMA IS EXPECTED TO BRING
HURRICANE CONDITIONS ON SATURDAY WHEN IT PASSES NEAR OR OVER THE
AREA.
2. HEAVY RAINS FROM NORMA WILL BEGIN TO IMPACT THE FAR SOUTHERN
PORTIONS OF CALIFORNIA BAJA SUR ON LATE FRIDAY, CONTINUING THROUGH
SUNDAY THIS RAINFALL MAY PRODUCE FLASH AND URBAN FLOODING, ALONG
WITH POSSIBLE MUDSLIDES IN AREAS OF HIGHER TERRAIN.
FORECAST POSITIONS AND MAX WINDS
INIT 20/0300Z 18.2N 108.1W 105 KT 120 MPH
12H 20/1200Z 19.2N 108.6W 100 KT 115 MPH
24H 21/0000Z 20.6N 109.2W 90 KT 105 MPH
36H 21/1200Z 22.1N 109.5W 85 KT 100 MPH
48H 22/0000Z 23.2N 109.4W 65 KT 75 MPH
60H 22/1200Z 23.8N 109.0W 60 KT 70 MPH
72H 23/0000Z 24.4N 108.1W 50 KT 60 MPH
96H 24/0000Z 25.3N 106.5W 30 KT 35 MPH...INLAND
120H 25/0000Z...DISSIPATED
FORECASTER PASCH
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