911
WTNT44 KNHC 272044
TCDAT4
TROPICAL DEPRESSION NINE DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092025
500 PM EDT SAT SEP 27 2025
THE ORGANIZATION OF THE DEPRESSION HAS NOT CHANGED MUCH SINCE THIS
MORNING. SOME DEEP CONVECTION HAS FLARED UP THIS AFTERNOON NEAR THE
ESTIMATED CENTER, WHICH APPEARS BROAD IN THE 850-MB FLIGHT-LEVEL
WIND DATA FROM THE AIR FORCE HURRICANE HUNTERS. THE EARLIER
SCATTEROMETER WINDS AND MORE RECENT AIRCRAFT DATA DO NOT SUGGEST THE
SYSTEM HAS INTENSIFIED. THE INITIAL INTENSITY IS HELD AT 30 KT FOR
THIS ADVISORY.
THE CENTER APPEARS TO BE SLIGHTLY SOUTH AND WEST OF PREVIOUS
ESTIMATES, WITH AN UNCERTAIN INITIAL MOTION OF 315/4 KT. OVER THE
NEXT COUPLE OF DAYS, THE SYSTEM SHOULD TURN MORE NORTH-NORTHWESTWARD
WITHIN THE FLOW BETWEEN AN UPPER TROUGH OVER THE SOUTHEAST U.S. AND
A SUBTROPICAL RIDGE OVER THE ATLANTIC. THIS FORECAST BRINGS THE
DEPRESSION OVER THE CENTRAL AND NORTHWESTERN BAHAMAS THROUGH EARLY
MONDAY, THEN TOWARD THE SOUTHEAST U.S. COAST BY TUESDAY. THE NHC
TRACK FORECAST IS VERY SIMILAR TO THE PREVIOUS ONE, WITH ONLY A
SLIGHT NUDGE WESTWARD BASED ON THE INITIAL POSITION ADJUSTMENTS
DURING THE DAY. WARM WATERS AND STRONG UPPER-LEVEL DIVERGENCE SHOULD
PROMOTE STRENGTHENING DURING THE NEXT FEW DAYS, BUT THIS COULD BE
TEMPERED BY MODERATE SOUTHERLY SHEAR OVER THE SYSTEM FROM AN
UPPER-LEVEL TROUGH. THE NHC INTENSITY FORECAST SHOWS STEADY
STRENGTHENING THROUGH EARLY NEXT WEEK, WITH THE SYSTEM BECOMING A
HURRICANE BY 60 H. THIS PREDICTION LIES CLOSE TO THE LATEST IVCN AND
HCCA AIDS.
THERE IS STILL ABOVE-AVERAGE UNCERTAINTY IN THE DETAILS OF THE
LONG-RANGE FORECAST. IN GENERAL, THE MODELS AGREE THAT THE PRESENCE
OF HURRICANE HUMBERTO TO THE EAST WILL RESULT IN A WEAKENING OF THE
PREVAILING STEERING CURRENTS, CAUSING THE SYSTEM TO SLOW DOWN AND
MEANDER NEAR THE SOUTHEAST U.S. COAST ON TUESDAY. WHILE THE CHANCES
OF A LANDFALL APPEAR LOWER THAN YESTERDAY, THERE ARE STILL SOME
HURRICANE REGIONAL MODELS AND ENSEMBLE SOLUTIONS THAT SHOW THIS
POSSIBILITY. GIVEN THE EXPECTED ASYMMETRIC STORM STRUCTURE, A RISK
OF SIGNIFICANT HEAVY RAINFALL, STORM SURGE, AND WIND IMPACTS EXISTS
FOR THE SOUTHEAST U.S. COAST EVEN IF THE STORM CENTER REMAINS
OFFSHORE. THE INCREASED TRACK SPREAD AT 96-120 H IS RELATED TO
WHETHER THE SYSTEM FEELS THE EFFECTS OF AN AMPLIFYING UPPER-LEVEL
TROUGH BEHIND HUMBERTO OVER THE WESTERN ATLANTIC. WHILE MANY GLOBAL
MODELS SHOW A SHARP EASTWARD TURN AND ACCELERATION AWAY FROM LAND,
THE SYSTEM FAILS TO BE CAPTURED BY THE TROUGH IN THE 12Z ECMWF AND
LINGERS OFFSHORE. THE NHC TRACK FORECAST AT DAYS 4-5 MAINTAINS A
CONSENSUS APPROACH AND SHOWS A SLOWER EASTWARD MOTION, BUT FUTURE
TRACK ADJUSTMENTS ARE LIKELY AS CONFIDENCE INCREASES. THE SYSTEM MAY
BE IN CLOSE PROXIMITY TO FRONTS BY THE END OF THE PERIOD, SO
EXTRATROPICAL TRANSITION COULD BEGIN AROUND OR SHORTLY AFTER DAY 5.
KEY MESSAGES:
1. THE DEPRESSION IS EXPECTED TO STRENGTHEN AND BRING TROPICAL STORM
CONDITIONS TO PORTIONS OF THE CENTRAL AND NORTHWESTERN BAHAMAS
THROUGH SUNDAY NIGHT. TROPICAL STORM CONDITIONS ARE ALSO POSSIBLE
ALONG PORTIONS OF THE EAST COAST OF CENTRAL FLORIDA BEGINNING
MONDAY, WHERE A TROPICAL STORM WATCH IS IN EFFECT.
2. RAINFALL WILL CONTINUE TO IMPACT EASTERN CUBA, HISPANIOLA,
JAMAICA, AND THE BAHAMAS THROUGH THE WEEKEND, WHICH WILL LIKELY
PRODUCE FLASH AND URBAN FLOODING. MUDSLIDES ARE POSSIBLE IN THE
HIGHER TERRAIN.
3. THERE IS A SIGNIFICANT THREAT OF HEAVY RAINFALL EARLY NEXT WEEK
FROM PORTIONS OF THE EAST COAST OF FLORIDA NORTHWARD INTO THE
CAROLINAS, WHICH COULD CAUSE FLASH, URBAN, AND RIVER FLOODING.
4. THE DEPRESSION IS EXPECTED TO BE AT OR NEAR HURRICANE INTENSITY
WHEN IT IS CLOSEST TO THE SOUTHEAST U.S. COAST EARLY NEXT WEEK,
WHERE THERE IS A RISK OF STORM SURGE AND WIND IMPACTS. ALTHOUGH IT
IS TOO SOON TO SPECIFY THE EXACT LOCATION AND MAGNITUDE OF IMPACTS,
RESIDENTS SHOULD CLOSELY MONITOR THE LATEST FORECAST UPDATES AND
ENSURE THAT THEY HAVE THEIR HURRICANE PLAN IN PLACE.
FORECAST POSITIONS AND MAX WINDS
INIT 27/2100Z 22.2N 76.5W 30 KT 35 MPH
12H 28/0600Z 23.3N 77.1W 35 KT 40 MPH
24H 28/1800Z 24.9N 77.6W 45 KT 50 MPH
36H 29/0600Z 26.7N 78.1W 55 KT 65 MPH
48H 29/1800Z 28.5N 78.6W 60 KT 70 MPH
60H 30/0600Z 30.0N 78.8W 65 KT 75 MPH
72H 30/1800Z 30.8N 78.6W 65 KT 75 MPH
96H 01/1800Z 31.1N 76.8W 65 KT 75 MPH
120H 02/1800Z 31.5N 74.0W 60 KT 70 MPH
FORECASTER REINHART
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page