054
WTPZ43 KNHC 051446
TCDEP3
HURRICANE RACHEL DISCUSSION NUMBER 34
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182026
800 AM PDT MON OCT 05 2026
RACHEL'S SATELLITE APPEARANCE CONTINUES TO DEPICT A RING OF DEEP
CONVECTION AROUND A LARGE EYE. THE SYSTEM IS DEALING WITH SOME
NORTHEASTERLY WIND SHEAR, WHICH HAS BROUGHT DRIER AIR THAT HAS
ENTRAINED INTO THE SYSTEM AND ERODED SOME OF THE NORTHERN,
PARTICULARLY NORTHWESTERN, SIDE OF THE CIRCULATION. SATELLITE
INTENSITY ESTIMATES HAVE DECREASED, WITH THE TAFB SUBJECTIVE DVORAK
CLASSIFICATION A T4.5/77 KT, AND USING THIS ESTIMATE, THE INITIAL
INTENSITY IS LOWERED TO 75 KT.
THE SYSTEM IS MOVING WESTWARD OR 275/6 KT, STEERED BY A MID-LEVEL
RIDGE LOCATED OVER THE SOUTHWESTERN UNITED STATES AND EASTERN
PACIFIC. THIS GENERAL FORWARD MOTION SHOULD CONTINUE FOR THE NEXT
SEVERAL DAYS. TOWARD THE END OF THE PERIOD, A MID- TO UPPER-LEVEL
TROUGH WILL MOVE INTO THE EASTERN PACIFIC NORTHWEST OF THE CYCLONE,
CAUSING THE SYSTEM TO SLOW AND MAKE A SHARP NORTHEASTWARD TURN. THE
LATEST NHC TRACK FORECAST IS VERY SIMILAR TO THE PREVIOUS ONE AND
CONTINUES TO BLEND THE HCCA AND GDMI MODEL SOLUTIONS.
RACHEL IS TRAVERSING MARGINALLY WARM SEA SURFACE TEMPERATURES OF
AROUND 26-27C WHILE DEALING WITH SOME SHEAR AND DRIER AIR. GIVEN
RECENT STRUCTURAL CHANGES, THERE WILL LIKELY BE FLUCTUATIONS IN
INTENSITY OVER THE NEXT DAY OR SO. BEYOND 36 TO 48 H, SEA SURFACE
TEMPERATURES COOL ALONG THE FORECAST TRACK, WHICH, COMBINED WITH
INCREASING DRY AIR, WILL INDUCE A MORE STEADY WEAKENING TREND.
DETERMINING WHEN RACHEL BECOMES POST-TROPICAL HAS BEEN TRICKY, AS
THE AFOREMENTIONED TROUGH THAT WILL TURN THE SYSTEM NORTHEASTWARD
MAY INDUCE SOME BAROCLINIC SUPPORT TO MAINTAIN CONVECTION. SIMULATED
INFRARED IMAGERY SHOWS THAT CONVECTION MAY BECOME LESS ORGANIZED BY
DAY 5, AND THE LATEST NHC FORECAST NOW DEPICTS THE SYSTEM BECOMING
POST-TROPICAL AT THAT TIME. THE LATEST NHC INTENSITY FORECAST
REMAINS AT THE HIGH END OF THE GUIDANCE ENVELOPE NEAR THE HCCA AND
GDMI IN THE SHORT TERM, THEN TRENDS CLOSER TO THE REST OF THE
CONSENSUS AIDS AS THE SYSTEM WEAKENS THROUGH THE END OF THE FORECAST
PERIOD.
FORECAST POSITIONS AND MAX WINDS
INIT 05/1500Z 20.4N 116.2W 75 KT 85 MPH
12H 06/0000Z 20.5N 117.3W 75 KT 85 MPH
24H 06/1200Z 20.5N 118.9W 70 KT 80 MPH
36H 07/0000Z 20.7N 120.2W 70 KT 80 MPH
48H 07/1200Z 21.1N 121.7W 65 KT 75 MPH
60H 08/0000Z 21.7N 123.1W 60 KT 70 MPH
72H 08/1200Z 22.0N 124.6W 50 KT 60 MPH
96H 09/1200Z 22.4N 126.6W 45 KT 50 MPH
120H 10/1200Z 23.1N 125.5W 35 KT 40 MPH...POST-TROPICAL
FORECASTER KELLY
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