463
WTPZ44 KNHC 240252
TCDEP4
HURRICANE NARDA DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL EP142025
800 PM MST TUE SEP 23 2025
NARDA APPEARS TO HAVE STRENGTHENED SINCE THE PREVIOUS ADVISORY, WITH
AN EYE, ALBEIT CLOUD-FILLED AND COLD, PERIODICALLY EVIDENT IN
VISIBLE AND INFRARED SATELLITE IMAGERY. THE CYCLONE CONTINUES TO
EXPERIENCE EASTERLY VERTICAL WIND SHEAR, WITH OUTFLOW RESTRICTED IN
THE EASTERN SEMICIRCLE. THIS IS EVIDENT IN SATELLITE IMAGERY AND
CONFIRMED BY THE LATEST UW-CIMSS SHEAR ANALYSIS, WHICH INDICATES 19
KT OF EASTERLY SHEAR. SUBJECTIVE DVORAK ESTIMATES FROM TAFB AND SAB
WERE 4.5/77 KT AND 5.0/90 KT, RESPECTIVELY, WHILE OBJECTIVE
ESTIMATES FROM UW-CIMSS RANGED FROM 80 TO 93 KT. TAKING A BLEND OF
THESE DATA, AND ACCOUNTING FOR THE IMPROVED SATELLITE PRESENTATION,
SUPPORTS RAISING THE INITIAL INTENSITY TO 85 KT FOR THIS ADVISORY.
NARDA IS ESTIMATED TO BE MOVING JUST SOUTH OF DUE WEST, OR 265
DEGREES, AT 11 KT. A GENERAL WESTWARD MOTION IS EXPECTED TO
CONTINUE DURING THE NEXT COUPLE OF DAYS AS THE CYCLONE IS STEERED BY
A STRENGTHENING SUBTROPICAL RIDGE TO ITS NORTH AND NORTHWEST. A
TURN TOWARD THE NORTHWEST IS EXPECTED AROUND DAY 3 AS A MID-LEVEL
LOW OVER SOUTHERN CALIFORNIA ERODES THE EASTERN PORTION OF THE
SUBTROPICAL RIDGE. A MORE NORTHWARD MOTION WITH A DECREASE IN
FORWARD SPEED IS FORECAST BY DAYS 4 AND 5 AS THE CYCLONE MOVES INTO
THE WEAKNESS IN THE SUBTROPICAL RIDGE CREATED BY THE MID-LEVEL LOW
TO ITS NORTH. THE OFFICIAL FORECAST TRACK IS VERY SIMILAR TO THE
PREVIOUS ADVISORY AND REMAINS CLOSE TO THE MIDDLE OF THE TRACK
GUIDANCE ENVELOPE.
NARDA WILL REMAIN EMBEDDED WITHIN A MOIST AIR MASS AND OVER VERY
WARM WATERS DURING THE NEXT COUPLE OF DAYS. SHEAR WILL HOLD AT
MODERATE LEVELS TONIGHT, WHICH MAY ALLOW FOR SOME SLIGHT
STRENGTHENING, AND THIS IS REFLECTED IN THE INTENSITY FORECAST. THE
EASTERLY SHEAR IS THEN FORECAST TO INCREASE TO NEAR 30 KT ON
WEDNESDAY, AND THIS IS EXPECTED TO DISRUPT THE CYCLONE ENOUGH TO
CAUSE SOME WEAKENING. NARDA SHOULD MOVE OUT OF THE MODERATE TO
STRONG EASTERLY SHEAR WHILE REMAINING OVER WARM WATERS AND
SURROUNDED BY MOIST MID-LEVEL AIR ON THURSDAY. THIS ENVIRONMENT
SHOULD ALLOW FOR A PERIOD OF RE-INTENSIFICATION, WITH NARDA FORECAST
TO PEAK AT MAJOR HURRICANE STRENGTH AROUND DAY 3. SEA SURFACE
TEMPERATURES WILL GRADUALLY DECREASE LATE IN THE FORECAST PERIOD,
WITH NARDA CROSSING THE 26C ISOTHERM AROUND DAY 4. THE CYCLONE WILL
ALSO BE MOVING INTO A MUCH DRIER MID-LEVEL AIRMASS AND A MORE STABLE
ENVIRONMENT, WHICH SHOULD RESULT IN STEADY WEAKENING BY DAY 4 AND
RAPID WEAKENING BY DAY 5. THE OFFICIAL INTENSITY FORECAST IS MOST
CLOSELY ALIGNED WITH THE HCCA INTENSITY AID.
FORECAST POSITIONS AND MAX WINDS
INIT 24/0300Z 15.3N 109.4W 85 KT 100 MPH
12H 24/1200Z 15.2N 111.0W 90 KT 105 MPH
24H 25/0000Z 15.2N 113.3W 80 KT 90 MPH
36H 25/1200Z 15.4N 115.6W 80 KT 90 MPH
48H 26/0000Z 15.8N 118.1W 85 KT 100 MPH
60H 26/1200Z 16.3N 120.3W 90 KT 105 MPH
72H 27/0000Z 17.1N 121.9W 100 KT 115 MPH
96H 28/0000Z 19.0N 123.4W 85 KT 100 MPH
120H 29/0000Z 21.5N 123.0W 55 KT 65 MPH
FORECASTER JELSEMA (CPHC)
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