200
WTPZ44 KNHC 242032
TCDEP4
HURRICANE NARDA DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL EP142025
200 PM MST WED SEP 24 2025
NARDA HAS BEEN FEELING THE IMPACT OF 20-25 KT NORTHEASTERLY WIND
SHEAR TODAY. AS A RESULT, THE CONVECTIVE STRUCTURE HAS DEGRADED
SOMEWHAT OVER THE PAST 6-12 HOURS. ALTHOUGH RECENT GPMI AND ASCAT
FIXES INDICATE THAT THE CENTER IS STILL WELL UNDERNEATH THE CENTRAL
DENSE OVERCAST, THE AREA OF CONVECTION WITH CLOUD TOPS COLDER THAN
-70C HAS SHRUNK SIGNIFICANTLY AND THE CONVECTION HAS BECOME SLIGHTLY
MORE ASYMMETRIC. THE LATEST SUBJECTIVE DVORAK ESTIMATES ARE
A CONSENSUS T-5.0/90 KT FROM TAFB AND SAB. HOWEVER, THE OBJECTIVE
INTENSITY ESTIMATES FROM UW-CIMSS HAVE DECREASED SIGNIFICANTLY OVER
THE PAST 6-12 HOURS, AND HAVE BEEN MOSTLY IN THE 65-80 KT RANGE.
TAKING INTO ACCOUNT BOTH THE SUBJECTIVE AND OBJECTIVE INTENSITY
ESTIMATES, THE INITIAL INTENSITY IS NUDGED DOWNWARD SLIGHTLY TO 85
KT FOR THIS ADVISORY.
RECENT FIXES INDICATE THAT NARDA IS MOVING SLIGHTLY SLOWER TOWARD
THE WEST THAN EARLIER, WITH THE CURRENT MOTION ESTIMATED AT 265/9
KT. A GENERAL WESTWARD MOTION WILL CONTINUE OVER THE NEXT 24-36 H,
FOLLOWED BY A GRADUAL TURN TO THE WEST-NORTHWEST AS THE CYCLONE IS
STEERED BY A MID-LEVEL RIDGE TO ITS NORTH. A MID-LEVEL LOW OVER
CENTRAL CALIFORNIA IS EXPECTED TO SINK SOUTHWARD TOWARD NORTHERN
BAJA CALIFORNIA BY FRIDAY NIGHT, WHICH WILL ERODE THE RIDGE AND
INDUCE A SHARP NORTHWARD TURN BY SATURDAY, ALONG WITH A DECREASE IN
FORWARD SPEED. THE OFFICIAL FORECAST IS SLIGHTLY SLOWER THAN THE
PREVIOUS NHC ADVISORY DURING THE FIRST 2 DAYS, MAINLY DUE TO THE
INITIAL POSITION BEING SLIGHTLY FARTHER EAST. AFTER THAT TIME, THE
LATEST FORECAST IS VERY NEAR THE PREVIOUS OFFICIAL FORECAST. THE
OFFICIAL FORECAST IS CLOSEST TO THE LATEST TVCE CONSENSUS THROUGH 60
H, AND THEN LIES IN BETWEEN THE TVCE AND HCCA FROM DAYS 3-5.
THE AFOREMENTIONED STRONG NORTHEASTERLY VERTICAL WIND SHEAR IS
EXPECTED TO CONTINUE THROUGH THE NEXT 12-24 H, THEN DECREASE TO
MODERATE MAGNITUDES BY THURSDAY AFTERNOON WHILE NARDA REMAINS OVER
WARM SEA-SURFACE TEMPERATURES AND WITHIN A MOIST ENVIRONMENT. THE
NHC FORECAST WILL THEREFORE CALL FOR CONTINUED WEAKENING THROUGH
THE NEXT 24 H, FOLLOWED BY SOME RESTRENGTHENING ON FRIDAY. ON
SATURDAY, NARDA IS FORECAST TO MOVE INTO COOLER WATERS AND CROSS THE
26C SEA-SURFACE TEMPERATURE ISOTHERM WHILE REACHING A SOMEWHAT DRIER
ENVIRONMENT. THE NHC FORECAST SHOWS RAPID WEAKENING OVER THE
WEEKEND AS NARDA MOVES OVER PROGRESSIVELY COOLER WATERS. OVERALL,
THE LATEST NHC INTENSITY FORECAST IS SLIGHTLY LOWER THAN THE
PREVIOUS PREDICTION.
IT SHOULD BE NOTED THAT THERE IS A HEALTHY AMOUNT OF TRACK MODEL
SPREAD BEYOND DAY 3. THESE TRACK DIFFERENCES WILL DETERMINE
WHAT WATER TEMPERATURES NARDA ENCOUNTERS IN 3-5 DAYS, WHICH
WILL AFFECT THE INTENSITY FORECAST (HOW QUICKLY NARDA WEAKENS DURING
THAT TIME PERIOD).
FORECAST POSITIONS AND MAX WINDS
INIT 24/2100Z 15.1N 112.3W 85 KT 100 MPH
12H 25/0600Z 15.3N 114.2W 80 KT 90 MPH
24H 25/1800Z 15.6N 116.7W 75 KT 85 MPH
36H 26/0600Z 16.0N 119.3W 75 KT 85 MPH
48H 26/1800Z 16.6N 121.5W 85 KT 100 MPH
60H 27/0600Z 17.3N 123.4W 90 KT 105 MPH
72H 27/1800Z 18.2N 124.4W 85 KT 100 MPH
96H 28/1800Z 20.1N 124.5W 55 KT 65 MPH
120H 29/1800Z 21.9N 123.5W 40 KT 45 MPH...POST-TROPICAL
FORECASTER HAGEN
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