756
WTPZ42 KNHC 091440
TCDEP2
TROPICAL DEPRESSION SEVENTEEN-E DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL EP172025
900 AM CST THU OCT 09 2025
THE LARGE AREA OF DISTURBED WEATHER LOCATED NEAR THE SOUTHWESTERN
COAST OF MEXICO (INVEST 90E) HAS CONTINUED TO GAIN ORGANIZATION.
CONVECTIVE BANDING HAS BECOME MORE EVIDENT IN THE SOUTHERN AND
WESTERN PART OF THE CIRCULATION, AND THE LATEST DVORAK ESTIMATES
FROM TAFB AND SAB ARE T2.0 AND T1.5, RESPECTIVELY. THE CONVECTIVE
PATTERN DOES SUGGEST THAT THE CIRCULATION MIGHT STILL BE A BIT
ELONGATED, BUT HOURLY OBSERVATIONS FROM A CRUISE SHIP, THE
NORWEGIAN JOY (C6CX3), HELPED TO LOCATE THE MAIN CENTER OF
CIRCULATION, PRESSURE MINIMUM, AND ESTIMATED WINDS. THE
CIRCULATION AND CONVECTION ARE NOW ORGANIZED ENOUGH TO CLASSIFY THE
SYSTEM AS A TROPICAL DEPRESSION.
THE CENTER WE'RE NOW TRACKING IS SOMEWHAT DISCONTINUOUS FROM A
FEATURE WE WERE TRACKING YESTERDAY FARTHER TO THE EAST, AND THE
INITIAL MOTION IS A ROUGH ESTIMATE OF WEST-NORTHWESTWARD, OR 285/12
KT. STRONG MID-LEVEL RIDGING OVER NORTHERN MEXICO AND THE
SOUTH-CENTRAL U.S. IS EXPECTED TO STEER THE DEPRESSION ON A QUICK
WEST-NORTHWESTWARD TO NORTHWESTWARD TRACK DURING THE NEXT 48 HOURS,
WITH THE CENTER PARALLELING THE SOUTHWESTERN COAST OF MEXICO THROUGH
LATE FRIDAY. THE SYSTEM IS THEN LIKELY TO ROUND THE WESTERN
PERIPHERY OF THE HIGH AND MOVE TOWARD THE BAJA CALIFORNIA PENINSULA
IN 2-3 DAYS. THE MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT FOR
THIS FIRST FORECAST, AND THE NHC TRACK IS CLOSE TO A BLEND OF THE
TVCE AND HCCA CONSENSUS AIDS.
THE DEPRESSION IS BEING AFFECTED BY STRONG EASTERLY SHEAR WHICH IS
LIKELY TO CONTINUE FOR THE NEXT 24 HOURS. HOWEVER, THE SYSTEM IS
ALSO OVER VERY WARM WATERS (29-30 DEGREES CELSIUS), IN AN
ENVIRONMENT OF STRONG UPPER-LEVEL DIVERGENCE, AND MOVING
QUICKLY, WHICH SHOULD ALL ALLOW FOR SOME MODEST STRENGTHENING
DURING THAT TIME. THE NHC FORECAST IS NEAR THE TOP END OF
THE GUIDANCE AND CLOSE TO THE HCCA AID IN THE SHORT TERM. ALTHOUGH
THE SHEAR IS FORECAST TO DECREASE SOME AFTER 24 HOURS, THE
MID-LEVEL ENVIRONMENT IS EXPECTED TO BECOME DRIER AND MORE STABLE
WHILE THE UPPER-LEVEL WINDS BECOME MORE CONVERGENT. THOSE CHANGES
SHOULD INDUCE WEAKENING WHILE THE SYSTEM IS APPROACHING THE SOUTHERN
BAJA CALIFORNIA PENINSULA. ALTHOUGH A REMNANT LOW POINT IS
PROVIDED OVER NORTHWESTERN MEXICO ON DAY 4, IT IS LIKELY THAT THE
SYSTEM WILL DISSIPATE BEFORE THAT TIME.
KEY MESSAGES:
1. TROPICAL STORM CONDITIONS ARE POSSIBLE ALONG PORTIONS OF THE
COAST OF SOUTHWESTERN MEXICO THROUGH LATE FRIDAY. INTERESTS IN
SOUTHERN BAJA CALIFORNIA SUR SHOULD MONITOR THE PROGRESS OF THE
SYSTEM.
2. HEAVY RAINFALL ASSOCIATED WITH THE TROPICAL DEPRESSION WILL
IMPACT COASTAL SECTIONS OF SOUTHWESTERN MEXICO THROUGH SATURDAY,
WHICH COULD RESULT IN FLASH FLOODING, PARTICULARLY IN AREAS OF
HIGHER TERRAIN.
FORECAST POSITIONS AND MAX WINDS
INIT 09/1500Z 16.2N 100.8W 30 KT 35 MPH
12H 10/0000Z 16.8N 102.6W 40 KT 45 MPH
24H 10/1200Z 18.1N 105.1W 45 KT 50 MPH
36H 11/0000Z 19.8N 107.8W 40 KT 45 MPH
48H 11/1200Z 21.4N 109.9W 35 KT 40 MPH
60H 12/0000Z 23.3N 111.0W 30 KT 35 MPH
72H 12/1200Z 25.5N 111.2W 30 KT 35 MPH
96H 13/1200Z 29.2N 110.7W 15 KT 15 MPH...POST-TROP/REMNT LOW
120H 14/1200Z...DISSIPATED
FORECASTER BERG
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