274
WTPZ43 KNHC 080841
TCDEP3
TROPICAL STORM RACHEL DISCUSSION NUMBER 45
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182026
200 AM PDT THU OCT 08 2026
DRY AIR CONTINUES TO EAT AWAY AT RACHEL'S CONVECTION. SATELLITE
IMAGERY OVER THE LAST COUPLE OF HOURS DEPICTS NOTICEABLE DEGRADATION
ACROSS THE WESTERN SEMICIRCLE, WITH DEEP CONVECTION WEAKENING
THROUGHOUT THE STORM AS SEEN THROUGH WARMING CLOUD-TOP TEMPERATURES.
WHILE TAFB'S SUBJECTIVE DVORAK INTENSITY ESTIMATE WAS UNCHANGED AT
4.0/65 KT, OBJECTIVE ESTIMATES FROM UW-CIMSS HAVE TRENDED DOWNWARD.
AS A RESULT OF THIS, COMBINED WITH THE WEAKENING TREND SEEN THROUGH
SATELLITE IMAGERY, THE INITIAL INTENSITY WAS SET AT 60 KT, AND
RACHEL HAS BEEN DOWNGRADED TO A TROPICAL STORM.
THE INITIAL MOTION WAS ESTIMATED AT 290/7 KT. RACHEL APPEARS TO HAVE
GAINED A SLIGHT AMOUNT OF SPEED SINCE LAST ADVISORY, ITS MOTION
DRIVEN PRIMARILY BY HIGH PRESSURE ANCHORED OVER THE SOUTHWESTERN US.
HOWEVER, A MID- TO UPPER-LEVEL TROUGH CURRENTLY SWEEPING ACROSS THE
PACIFIC IS FORECAST TO PICK UP RACHEL AND TURN IT TO THE NORTHEAST
IN APPROXIMATELY 24 HOURS. THIS WILL COINCIDE WITH AN INCREASE IN
FORWARD SPEED. WHILE TRACK GUIDANCE CONTINUES TO EXHIBIT A FAIR
AMOUNT OF SPREAD AFTER THIS TROUGH INTERACTION, SKILLED GUIDANCE HAS
BECOME MORE ALIGNED ON A SOLUTION SINCE THE LAST ADVISORY. THE
LATEST NHC TRACK FORECAST NUDGES RACHEL'S TRAJECTORY MORE TOWARDS
HCCA AND GDMI, WHICH RESULTS IN A SLIGHT SHIFT TOWARD THE RIGHT AS
THE STORM THE STORM APPROACHES NORTHERN BAJA CALIFORNIA.
AS RACHEL CONTINUES TO MOVE ABOUT IN AN ENVIRONMENT CHARACTERIZED BY
COOLING SSTS AND DRY MID-LEVEL AIR, ITS CONVECTION IS EXPECTED TO
FURTHER DEGRADE, THUS INDUCING FURTHER WEAKENING. ONCE THE
AFOREMENTIONED TROUGH SHIFTS RACHEL'S PATH, VERTICAL WIND SHEAR IS
ALSO EXPECTED TO INCREASE SUBSTANTIALLY, LEADING TO EVEN FURTHER
WEAKENING AS THE STORM APPROACHES NORTHERN BAJA CALIFORNIA AND
SOUTHERN CALIFORNIA. SIMULATED SATELLITE IMAGERY EVEN SUGGESTS THAT
RACHEL MAY LOSE ITS DEEP CONVECTION ALTOGETHER BY THE TIME IT HITS
LAND, HOWEVER STRONG WINDS AND HEAVY RAIN CAN STILL BE EXPECTED
WHEREVER RACHEL MAKES LANDFALL, EITHER AS A TROPICAL STORM OR A
POST-TROPICAL CYCLONE. THE LATEST NHC INTENSITY FORECAST REFLECTS A
MORE STEADY WEAKENING TREND COMPARED TO THE PREVIOUS ADVISORY, WITH
RACHEL FORECAST TO BECOME POST-TROPICAL BETWEEN 72 AND 96 HOURS, OR
SHORTLY AFTER MAKING LANDFALL.
KEY MESSAGES:
1. RACHEL IS EXPECTED TO APPROACH THE COAST OF EXTREME NORTHERN BAJA
CALIFORNIA AND SOUTHERN CALIFORNIA AT OR NEAR TROPICAL STORM
STRENGTH OVER THE WEEKEND, POTENTIALLY BRINGING STRONG WINDS AND
COASTAL FLOODING TO PORTIONS OF THOSE AREAS. GUSTY WINDS COULD
SPREAD OVER INTERIOR PORTIONS OF THE SOUTHWEST UNITED STATES INTO
EARLY NEXT WEEK.
2. MOISTURE ASSOCIATED WITH RACHEL WILL SPREAD OVER PORTIONS OF THE
SOUTHWEST UNITED STATES AND NORTHERN BAJA CALIFORNIA PENINSULA
THROUGH THIS WEEKEND. THIS WILL LEAD TO INCREASING COVERAGE OF
RAINFALL AND A THREAT OF FLASH AND URBAN FLOODING.
3. SWELLS PARTLY GENERATED BY RACHEL WILL BUILD ALONG THE COAST OF
SOUTHERN CALIFORNIA AND NORTHERN BAJA CALIFORNIA THROUGH THE
WEEKEND. THESE SWELLS ARE LIKELY TO CAUSE LIFE-THREATENING SURF AND
RIP CURRENT CONDITIONS. PLEASE CONSULT PRODUCTS FROM YOUR LOCAL
WEATHER OFFICE.
FORECAST POSITIONS AND MAX WINDS
INIT 08/0900Z 21.8N 123.9W 60 KT 70 MPH
12H 08/1800Z 22.1N 124.3W 55 KT 65 MPH
24H 09/0600Z 22.5N 125.0W 50 KT 60 MPH
36H 09/1800Z 22.9N 124.7W 45 KT 50 MPH
48H 10/0600Z 24.0N 122.8W 45 KT 50 MPH
60H 10/1800Z 26.4N 119.9W 45 KT 50 MPH
72H 11/0600Z 30.2N 116.7W 40 KT 45 MPH
96H 12/0600Z 39.9N 112.2W 25 KT 30 MPH...POST-TROP/INLAND
120H 13/0600Z...DISSIPATED
FORECASTER EVANS/ROBERTS
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