225
WTPZ41 KNHC 131453
TCDEP1
TROPICAL DEPRESSION TWENTY-ONE-E DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL EP212026
900 AM CST TUE OCT 13 2026
SATELLITE IMAGES SHOW THAT THE AREA OF LOW PRESSURE LOCATED TO THE
SOUTH OF SOUTHERN MEXICO HAS BECOME BETTER ORGANIZED OVER THE PAST
24 HOURS. LARGE AREAS OF BANDED DEEP CONVECTION ARE SEEN TO THE
NORTH AND THE EAST OF THE LOW-LEVEL CENTER. AN OSCAT PASS FROM 0630
UTC THIS MORNING SHOWED A CLOSED CIRCULATION, BUT IT WAS A BIT SHORT
OF BEING CONSIDERED WELL-DEFINED AT THAT TIME SINCE THE DATA STILL
SHOWED A BROAD AND SOMEWHAT ELONGATED AREA OF WEAK WINDS WITHIN
ABOUT 75 N MI OF THE CENTER. HOWEVER, THE CONVECTIVE ORGANIZATION
AND CURVED BANDING HAS INCREASED SINCE THAT TIME, AND THE
CIRCULATION APPEARS TO HAVE TIGHTENED UP A BIT OVER THE PAST SEVERAL
HOURS. THE SUBJECTIVE DVORAK ESTIMATE FROM TAFB IS T2.0/30 KT, AND
IT IS ESTIMATED THAT A TROPICAL DEPRESSION HAS FORMED WITH AN
INITIAL INTENSITY OF 30 KT.
THE INITIAL MOTION OF TROPICAL DEPRESSION TWENTY-ONE-E IS ESTIMATED
TO BE NORTHWESTWARD, OR 305/9 KT. A WEST-NORTHWESTWARD TO
NORTHWESTWARD MOTION SHOULD CONTINUE OVER THE NEXT 36 HOURS WHILE A
MID-LEVEL RIDGE PERSISTS OVER THE NORTHWESTERN GULF OF AMERICA.
THEREAFTER, A TURN TO THE NORTHWEST OR NORTH-NORTHWEST IS LIKELY AS
THE RIDGE WEAKENS. A DECREASE IN FORWARD SPEED IS ALSO EXPECTED
AFTER DAY 2 AS THE CYCLONE GETS CAUGHT IN WEAKER STEERING CURRENTS
IN BETWEEN THE WEAK RIDGE TO ITS NORTH AND HURRICANE SIMON TO ITS
NORTHWEST. SPREAD IN THE TRACK FORECAST IS LARGER THAN NORMAL FROM
DAY 3 TO 5, AND SOME OF THIS UNCERTAINTY IS LIKELY ALSO DUE TO
UNCERTAINTY IN SIMON'S TRACK. A COLD FRONT MOVING SOUTHWARD FROM
TEXAS INTO MEXICO TOWARD THE END OF THE FORECAST PERIOD COULD HELP
DRAW SIMON CLOSER TO THE COASTLINE OF MEXICO, IF THE FRONT IS POTENT
ENOUGH. REGARDLESS, TROPICAL DEPRESSION 21-E COULD POTENTIALLY BE
VERY CLOSE TO THE COAST OF MEXICO AS A HURRICANE OVER THE WEEKEND,
AND SEVERAL GOOGLE DEEPMIND ENSEMBLE MEMBERS SHOW THE CYCLONE MAKING
LANDFALL IN SOUTHWESTERN OR WEST-CENTRAL MEXICO. THE NHC FORECAST
CLOSELY FOLLOWS THE HFIP CORRECTED CONSENSUS APPROACH (HCCA), AND
ISN'T TOO FAR OFF FROM THE GOOGLE DEEPMIND ENSEMBLE MEAN.
CONFIDENCE IN THE TRACK FORECAST IS LOW, ESPECIALLY BEYOND DAY 3.
THE CYCLONE IS FORECAST TO TRAVERSE EXTREMELY FAVORABLE OCEANIC AND
ATMOSPHERIC CONDITIONS FOR AT LEAST THE NEXT 3 TO 4 DAYS. THE NHC
INTENSITY FORECAST SHOWS STEADY STRENGTHENING OVER THE NEXT 24 HOURS
AS THE CYCLONE WORKS TO DEVELOP A CONVECTIVE CORE. AFTER THAT TIME,
RAPID INTENSIFICATION IS FORECAST DURING THE 24 TO 72 H TIME WINDOW.
THE DTOPS IN THE ECMWF-BASED SHIPS GUIDANCE IS FORECASTING A 74
PERCENT CHANCE OF A 65-KT INCREASE OVER THE NEXT 72 H. THE NHC
INTENSITY FORECAST IS EVEN MORE AGGRESSIVE AND SHOWS 85 KNOTS OF
STRENGTHENING OVER THE NEXT 72 H. THE NHC FORECAST IS SLIGHTLY
BELOW THE HCCA AND GDMI IN THE SHORT TERM, BUT VERY NEAR THE HCCA
AND GDMI BEYOND DAY 2. THE HAFS-A AND HAFS-B MODELS STRENGTHEN THE
CYCLONE TO A CATEGORY 4, AND 36 OF THE 50 GOOGLE DEEPMIND MEMBERS
MAKE IT A CATEGORY 4 OR STRONGER, SO THE NHC FORECAST WILL
AGGRESSIVELY SHOW THIS SYSTEM REACHING CATEGORY 4 STRENGTH AT DAYS 3
AND 4. BEYOND DAY 4, THE POSSIBILITY OF INCREASING VERTICAL WIND
SHEAR AND LAND INTERACTION COULD INDUCE SOME WEAKENING, AND MOST OF
THE GUIDANCE SHOWS THE SYSTEM LOSING SOME INTENSITY AFTER DAY 4.
CONFIDENCE IN THE INTENSITY FORECAST IS ABOVE AVERAGE. WE ARE
FAIRLY CONFIDENT IT WILL BECOME A STRONG HURRICANE DUE TO THE
FAVORABLE ENVIRONMENTAL CONDITIONS AND MODEL GUIDANCE.
FORECAST POSITIONS AND MAX WINDS
INIT 13/1500Z 9.8N 96.5W 30 KT 35 MPH
12H 14/0000Z 10.5N 97.6W 40 KT 45 MPH
24H 14/1200Z 11.3N 99.3W 50 KT 60 MPH
36H 15/0000Z 12.0N 100.5W 65 KT 75 MPH
48H 15/1200Z 12.8N 101.4W 80 KT 90 MPH
60H 16/0000Z 13.7N 101.9W 100 KT 115 MPH
72H 16/1200Z 14.5N 102.2W 115 KT 130 MPH
96H 17/1200Z 16.5N 103.5W 120 KT 140 MPH
120H 18/1200Z 18.6N 105.3W 105 KT 120 MPH
FORECASTER HAGEN
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