878
WTPZ42 KNHC 212039
TCDEP2
HURRICANE NORMA DISCUSSION NUMBER 17
NWS NATIONAL HURRICANE CENTER MIAMI FL EP172023
300 PM MDT SAT OCT 21 2023
NORMA MADE LANDFALL ALONG THE SOUTHERN TIP OF THE BAJA CALIFORNIA
PENINSULA JUST WEST-NORTHWEST OF CABO SAN LUCAS AROUND 2015 UTC WITH
ESTIMATED MAXIMUM WINDS OF 70 KT. THE CENTER OF THE TROPICAL CYCLONE
HAS BECOME EXPOSED THIS AFTERNOON, AS INCREASING SOUTHERLY SHEAR
STRIPPED AWAY THE ASSOCIATED DEEP CONVECTION. AN AIR FORCE HURRICANE
HUNTER AIRCRAFT SAMPLED NORMA SHORTLY BEFORE LANDFALL AND FOUND
HURRICANE-FORCE SFMR WINDS IN THE NORTHWEST QUADRANT, WITH A PEAK OF
73 KT. A CENTER DROPSONDE SUPPORTED A MINIMUM PRESSURE OF AROUND 974
MB. ASSUMING SOME CONTINUED WEAKENING SINCE THE PLANE DEPARTED, THE
LANDFALL AND ADVISORY INTENSITY IS SET AT 70 KT.
WITH NORMA BECOMING A MORE SHALLOW VORTEX, IT HAS SLOWED DOWN AND
TURNED NORTH-NORTHEASTWARD (15 DEGREES/5 KT). THE CYCLONE WILL MOVE
ACROSS THE SOUTHERN PORTION OF BAJA CALIFORNIA SUR THROUGH TONIGHT,
WITH CONTINUED WEAKENING EXPECTED DUE TO THE NEGATIVE INFLUENCES OF
INCREASING SHEAR, DRIER AIR, AND LAND INTERACTION. NORMA SHOULD
EMERGE OVER THE SOUTHERN GULF OF CALIFORNIA AS A TROPICAL STORM
EARLY SUNDAY, THEN MOVE NORTHEASTWARD AND MAKE LANDFALL ALONG THE
COAST OF SINALOA IN WESTERN MEXICO WITHIN THE TROPICAL STORM WARNING
AREA. THE UPDATED NHC TRACK FORECAST HAS BEEN NUDGED SLIGHTLY NORTH
OF THE PREVIOUS PREDICTION, IN AGREEMENT WITH THE LATEST MULTI-MODEL
CONSENSUS AIDS. ONCE NORMA MOVES INLAND, IT WILL QUICKLY DISSIPATE
OVER THE RUGGED TERRAIN OF WESTERN MEXICO.
KEY MESSAGES:
1. HEAVY RAINS FROM NORMA WILL CONTINUE TO IMPACT SOUTHERN PORTIONS
OF BAJA CALIFORNIA SUR THROUGH SUNDAY, AND THROUGH SINALOA INTO
MONDAY. THIS RAINFALL WILL PRODUCE FLASH AND URBAN FLOODING, ALONG
WITH MUDSLIDES IN AREAS OF HIGHER TERRAIN.
2. HURRICANE CONDITIONS WILL CONTINUE FOR THE NEXT FEW HOURS WITHIN
THE HURRICANE WARNING AREA OVER THE FAR SOUTHERN BAJA CALIFORNIA
PENINSULA.
3. NORMA IS FORECAST TO BRING TROPICAL STORM CONDITIONS TO PORTIONS
OF THE WEST COAST OF MEXICO WITHIN THE TROPICAL STORM WARNING AREA
BEGINNING EARLY SUNDAY.
FORECAST POSITIONS AND MAX WINDS
INIT 21/2100Z 23.1N 110.0W 70 KT 80 MPH
12H 22/0600Z 23.7N 109.9W 60 KT 70 MPH...INLAND
24H 22/1800Z 24.5N 109.1W 55 KT 65 MPH...OVER WATER
36H 23/0600Z 24.8N 108.3W 40 KT 45 MPH...NEAR THE COAST
48H 23/1800Z 25.1N 107.5W 30 KT 35 MPH...POST-TROP/INLAND
60H 24/0600Z...DISSIPATED
FORECASTER REINHART
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