120
WTPZ43 KNHC 290846
TCDEP3
TROPICAL STORM RACHEL DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182026
300 AM CST TUE SEP 29 2026
RACHEL HAS BEEN EXHIBITING A PATTERN OF BURSTING VERY DEEP
CONVECTION OVER THE PAST SEVERAL HOURS WITH CLOUD TOPS AS COLD AS
-90 DEG C. HOWEVER, THE DEEP CONVECTIVE AREA HAS A RATHER
SHAPELESS APPEARANCE ON SATELLITE IMAGERY, AND IS LACKING
CONVECTIVE BANDING FEATURES. THE STORM CONTINUES TO EXPERIENCE
SOME NORTH-NORTHEASTERLY VERTICAL WIND SHEAR. OBSERVATIONS FROM A
NOAA HURRICANE HUNTER TAIL DOPPLER RADAR RESEARCH MISSION INDICATE
THAT THE SYSTEM IS BECOMING MORE VERTICALLY ALIGNED. NONETHELESS,
SINCE THE SYSTEM'S SATELLITE SIGNATURE INDICATES ARRESTED
DEVELOPMENT, THE ADVISORY INTENSITY IS HELD AT 50 KT WHICH IS A
LITTLE ABOVE THE LATEST DVORAK ESTIMATE FROM TAFB.
BLENDING CENTER POSITION ESTIMATES FROM THE NOAA AIRCRAFT ALONG
WITH GEOSTATIONARY AND MICROWAVE SATELLITE-BASE CENTER FIXES, THE
MOTION ESTIMATE IS 300/10 KT WHICH IS ABOUT THE SAME AS BEFORE.
RACHEL SHOULD MOVE ALONG THE SOUTHWESTERN SIDE OF A MID-LEVEL RIDGE
WITH A MORE NORTHWESTWARD MOTION BEING INDUCED BY A 500 MB CUTOFF
LOW OVER THE SOUTHWESTERN UNITED STATES DURING THE NEXT FEW DAYS.
BY LATE WEEK, THE TROUGH IS FORECAST TO LIFT OUT AND THE RIDGE
SHOULD BECOME REESTABLISHED TO THE NORTH, WITH RACHEL EXPECTED TO
RESUME A WEST-NORTHWESTWARD MOTION BY AROUND 72 HOURS. THE
OFFICIAL TRACK FORECAST IS SLIGHTLY SOUTH OF THE ONE FROM THE
PREVIOUS ADVISORY BUT ON THE NORTHERN SIDE OF THE TRACK GUIDANCE
ENVELOPE.
RACHEL SHOULD BE MOVING THROUGH A FAVORABLE ATMOSPHERIC
THERMODYNAMIC ENVIRONMENT AND OVER GENERALLY WARM SEA SURFACE
TEMPERATURES DURING THE NEXT SEVERAL DAYS. ASSUMING THAT THE
VERTICAL WIND SHEAR DOES NOT BECOME TOO PROHIBITIVE, STRENGTHENING
IS FORECAST. THERE IS A POSSIBILITY THAT THE SYSTEM'S
INTENSIFICATION COULD BE SLIGHTLY INHIBITED BY SOME COOLER WATERS
DUE TO THE WAKE OF HURRICANE POLO. THE OFFICIAL INTENSITY FORECAST
IS CLOSE TO THE SIMPLE INTENSITY MODEL CONSENSUS, BUT THE CORRECTED
CONSENSUS GUIDANCE IS SOMEWHAT HIGHER, AS NOTED IN THE PREVIOUS
ADVISORY DISCUSSION.
KEY MESSAGES:
1. ALTHOUGH THE CORE OF RACHEL IS FORECAST TO REMAIN OFFSHORE OF
MEXICO, TROPICAL-STORM-FORCE WINDS ARE EXPECTED ALONG A PORTION OF
THE COAST OF SOUTHWESTERN MEXICO IN THE TROPICAL STORM WARNING AREA
TODAY. TROPICAL STORM CONDITIONS ARE POSSIBLE IN THE WATCH AREA
TONIGHT OR ON WEDNESDAY.
2. OUTER BANDS FROM RACHEL WILL BRING LOCALLY HEAVY RAINFALL TO
PORTIONS OF COASTAL SOUTHWEST MEXICO THROUGH THURSDAY. THIS RAINFALL
MAY PRODUCE AREAS OF FLOODING AND MUDSLIDES, ESPECIALLY IN REGIONS
OF STEEP TERRAIN.
3. LARGE WAVES COULD PRODUCE LIFE-THREATENING SURF AND RIP CURRENT
CONDITIONS ALONG PORTIONS OF THE SOUTHWESTERN COAST OF MEXICO DURING
THE NEXT SEVERAL DAYS.
FORECAST POSITIONS AND MAX WINDS
INIT 29/0900Z 14.7N 104.3W 50 KT 60 MPH
12H 29/1800Z 15.7N 105.4W 55 KT 65 MPH
24H 30/0600Z 17.1N 106.8W 65 KT 75 MPH
36H 30/1800Z 18.4N 108.1W 75 KT 85 MPH
48H 01/0600Z 19.3N 109.1W 80 KT 90 MPH
60H 01/1800Z 19.8N 109.7W 85 KT 100 MPH
72H 02/0600Z 20.2N 110.3W 85 KT 100 MPH
96H 03/0600Z 20.7N 111.6W 85 KT 100 MPH
120H 04/0600Z 21.1N 113.5W 85 KT 100 MPH
FORECASTER PASCH
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