575
WTPZ44 KNHC 250845
TCDEP4
HURRICANE NARDA DISCUSSION NUMBER 15
NWS NATIONAL HURRICANE CENTER MIAMI FL EP142025
200 AM MST THU SEP 25 2025
NARDA IS HOLDING STEADY THIS MORNING DESPITE PERSISTENT 20 KT OF
NORTHEASTERLY VERTICAL WIND SHEAR. RECENT SATELLITE IMAGERY SHOWS A
WELL-DEFINED CENTRAL DENSE OVERCAST (CDO) WITH CLOUD TOPS NEAR –90
C, ALONG WITH A CURVED BAND WRAPPING INTO THE CENTER FROM THE
SOUTHWEST. THE LATEST SUBJECTIVE DVORAK INTENSITY ESTIMATES FROM
TAFB AND SAB ARE BOTH T4.5/77 KT, WHILE OBJECTIVE INTENSITY
ESTIMATES FROM UW-CIMSS RANGE BETWEEN 61 AND 72 KT. GIVEN THE
IMPROVED SATELLITE PRESENTATION OVER THE PAST FEW HOURS AND THESE
ESTIMATES, THE INITIAL INTENSITY IS HELD AT 80 KT.
THE INITIAL MOTION IS TOWARD THE WEST NEAR 280/13 KT, AND THIS
FORWARD SPEED IS EXPECTED TO REMAIN STEADY THROUGH 48 H (FRIDAY
NIGHT). AFTER THAT TIME, NARDA SHOULD BEGIN TO SLOW DOWN AS IT TURNS
WEST-NORTHWESTWARD, THEN NORTHWESTWARD, AND EVENTUALLY NORTHWARD
THROUGH THE WEEKEND IN RESPONSE TO A WEAKNESS DEVELOPING IN THE
SUBTROPICAL RIDGE. THERE REMAINS CONSIDERABLE SPREAD IN THE GUIDANCE
REGARDING THE TIMING OF THIS NORTHWARD TURN. THE ECMWF SHOWS A LATER
TURN NEAR 72 H (SATURDAY NIGHT), WHILE THE CONSENSUS AIDS INDICATE
AN EARLIER TURN, AROUND 60 H (DURING THE DAY SATURDAY). A LATER TURN
WOULD KEEP NARDA OVER WARMER WATERS LONGER AND ALLOW IT TO MAINTAIN
STRENGTH, WHEREAS AN EARLIER TURN WOULD MOVE THE SYSTEM OVER COOLER
WATERS SOONER AND RESULT IN QUICKER WEAKENING. THE OFFICIAL TRACK
FORECAST IS SLIGHTLY TO THE LEFT OF THE PREVIOUS ONE AFTER 60 H,
REFLECTING A BLEND OF THE PRIOR FORECAST AND THE CONSENSUS AIDS.
ONLY SLIGHT WEAKENING IS FORECAST DURING THE NEXT 12-24 H WHILE THE
NORTHEASTERLY SHEAR PERSISTS. BETWEEN 24 AND 48 H (TONIGHT INTO
FRIDAY NIGHT), THE SHEAR IS EXPECTED TO EASE TO MORE MODERATE LEVELS
WHILE NARDA REMAINS OVER WARM WATERS WITH PLENTY OF MID- TO
UPPER-LEVEL MOISTURE, WHICH SHOULD ALLOW FOR A PERIOD OF
RE-STRENGTHENING. THIS FORECAST LIES NEAR THE MIDDLE TO UPPER
PORTION OF THE GUIDANCE ENVELOPE DURING THAT BRIEF WINDOW (24–36 H).
BY AROUND 60 H (SATURDAY), SEA-SURFACE TEMPERATURES ALONG THE TRACK
ARE FORECAST TO FALL BELOW 26 C, AND STEADY WEAKENING IS FORECAST
THEREAFTER. NARDA IS EXPECTED TO FALL BELOW HURRICANE STRENGTH BY
THE END OF THE WEEKEND AND BECOME A POST-TROPICAL REMNANT LOW BY DAY
5 (MONDAY NIGHT). THE LATEST INTENSITY FORECAST IS VERY SIMILAR TO
THE PREVIOUS ONE AND REMAINS NEAR THE MIDDLE TO UPPER PORTION OF THE
GUIDANCE ENVELOPE.
FORECAST POSITIONS AND MAX WINDS
INIT 25/0900Z 15.6N 114.8W 80 KT 90 MPH
12H 25/1800Z 15.8N 116.8W 75 KT 85 MPH
24H 26/0600Z 16.3N 119.5W 80 KT 90 MPH
36H 26/1800Z 17.0N 122.0W 85 KT 100 MPH
48H 27/0600Z 17.5N 124.0W 85 KT 100 MPH
60H 27/1800Z 18.2N 125.3W 80 KT 90 MPH
72H 28/0600Z 19.2N 125.8W 65 KT 75 MPH
96H 29/0600Z 21.2N 125.6W 40 KT 45 MPH
120H 30/0600Z 23.0N 124.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
FORECASTER GIBBS (CPHC)
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