902
WTPZ43 KNHC 270855
TCDEP3
TROPICAL DEPRESSION EIGHTEEN-E DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182026
300 AM CST SUN SEP 27 2026
THE TROPICAL DISTURBANCE LOCATED SOUTH OF MEXICO, FORMERLY INVEST
90E, HAS BECOME BETTER ORGANIZED BASED ON SATELLITE IMAGERY OVER THE
LAST SEVERAL HOURS. SCATTEROMETRY DATA FROM AROUND 0300 UTC DEPICTS
A CLOSED CIRCULATION, WITH THE SYSTEM MOVING INTO A FAVORABLE
ENVIRONMENT FOR FURTHER DEVELOPMENT. SUBJECTIVE DVORAK
INTENSITY ANALYSIS FROM TAFB ALSO RATED THE SYSTEM AT 2.0/30 KT.
THEREFORE, ADVISORIES HAVE BEGUN FOR TROPICAL DEPRESSION
EIGHTEEN-E.
THE INITIAL MOTION IS SOMEWHAT UNCERTAIN SINCE THE CYCLONE HAS ONLY
RECENTLY FORMED, BUT THE MOTION ESTIMATE IS AROUND 285/9 KT. TRACK
GUIDANCE IS IN GOOD AGREEMENT ON STEERING THIS SYSTEM GENERALLY TO
THE WEST-NORTHWEST OVER THE NEXT SEVERAL DAYS, WITH AN INCREASE IN
FORWARD SPEED AS IT RUNS SOUTH OF A MID-LEVEL HIGH OVER MEXICO. THE
CURRENT NHC TRACK FORECAST GENERALLY FALLS WITHIN THE MIDDLE OF THE
GUIDANCE ENVELOPE, FAVORING HCCA IN PARTICULAR.
SHIPS GUIDANCE SUGGESTS THAT VERTICAL WIND SHEAR MAY BE AN
INHIBITING FACTOR FOR DEVELOPMENT FOR THE FIRST 24 H, BEFORE THE
DEPRESSION IS EXPECTED TO GRADUALLY STRENGTHEN AS SSTS REMAIN WARM
AND MID-LEVEL MOISTURE APPEARS FAVORABLE. THERE IS SOME UNCERTAINTY
WITH REGARDS TO SSTS DUE TO COLDER WATERS POTENTIALLY BEING CHURNED
UP IN THE WAKE OF HURRICANE POLO, SO THE CURRENT INTENSITY FORECAST
IS A LITTLE CONSERVATIVE AT FIRST, BEFORE DEPICTING GRADUAL
STRENGTHENING THROUGH THE LATE WEEKEND ONWARD. THIS STILL FALLS
AROUND THE MEDIAN OF THE GUIDANCE ENVELOPE.
FORECAST POSITIONS AND MAX WINDS
INIT 27/0900Z 12.2N 99.1W 30 KT 35 MPH
12H 27/1800Z 12.7N 99.6W 30 KT 35 MPH
24H 28/0600Z 13.2N 100.8W 35 KT 40 MPH
36H 28/1800Z 13.8N 102.2W 45 KT 50 MPH
48H 29/0600Z 14.7N 104.1W 55 KT 65 MPH
60H 29/1800Z 15.7N 105.9W 65 KT 75 MPH
72H 30/0600Z 16.9N 107.7W 75 KT 85 MPH
96H 01/0600Z 18.7N 109.6W 80 KT 90 MPH
120H 02/0600Z 19.7N 110.3W 75 KT 85 MPH
FORECASTER EVANS/PASCH
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