457
AXNT20 KNHC 032315
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0015 UTC SAT OCT 4 2025
TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA, CENTRAL AMERICA
GULF OF AMERICA, CARIBBEAN SEA, NORTHERN SECTIONS OF SOUTH
AMERICA, AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 31N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY, WEATHER OBSERVATIONS, RADAR AND METEOROLOGICAL ANALYSIS.
BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2300 UTC.
..SPECIAL FEATURES
SIGNIFICANT SWELL EVENT OVER THE WESTERN AND CENTRAL ATLANTIC:
LARGE NORTHERLY SWELL GENERATED BY STORM-FORCE WINDS ASSOCIATED
WITH EXTRA-TROPICAL CYCLONE IMELDA IN THE NORTHERN ATLANTIC ARE
PROPAGATING ACROSS THE FORECAST WATERS S OF 31N BUILDING SEAS TO
18 TO 20 FT OVER THE CENTRAL ATLANTIC. SEAS 12 FT OR GREATER
DOMINATE A LARGE AREA, PARTICULARLY N OF 25N BETWEEN 45W AND 65W.
ALTIMETER DATA AND BUOY OBSERVATIONS CONFIRMED THE PRESENCE OF
THESE SEA HEIGHTS. THIS SWELL EVENT WILL CONTINUE TO EXPAND
SOUTHEASTWARD THIS WEEKEND, LEADING TO WIDESPREAD ROUGH SEAS
NORTH OF 10N. VERY ROUGH SEAS IN EXCESS OF 12 FT ARE EXPECTED
NORTH OF 23N THIS WEEKEND, INCLUDING NEAR THE NORTHERN BAHAMAS.
IN ADDITION, THIS SWELL EVENT WILL ALSO SUSTAIN DANGEROUS SURF
CONDITIONS, SIGNIFICANT BEACH EROSION AND PROBABLE LOCAL COASTAL
INUNDATION ALONG THE EAST-FACING SHORES OF GEORGIA AND FLORIDA,
THE NORTH AND EAST-FACING SHORES OF THE BAHAMAS, AND THE NORTH-
FACING SHORES ACROSS HISPANIOLA, PUERTO RICO, THE VIRGIN AND
LEEWARD ISLANDS. REFER TO YOUR LOCAL WEATHER AGENCIES FOR THE
LATEST STATEMENTS.
PLEASE READ THE LATEST NWS HIGH SEAS FORECAST ISSUED BY THE
NATIONAL HURRICANE CENTER AT WEBSITE
HTTPS://WWW.NHC.NOAA.GOV/TEXT/MIAHSFAT2.SHTML FOR FURTHER
DETAILS.
..TROPICAL WAVES
A TROPICAL WAVE HAS JUST EMERGED OFF THE COAST OF AFRICA. ITS
AXIS IS ALONG 16W/17W. THE WAVE IS FORECAST TO INTERACT WITH
ANOTHER DISTURBANCE OVER THE EASTERN TROPICAL ATLANTIC, AND THEN
MOVE WESTWARD AFTER THAT. ENVIRONMENTAL CONDITIONS ARE EXPECTED
TO BECOME CONDUCIVE FOR SOME SLOW DEVELOPMENT OF THE SYSTEM IN A
FEW DAYS, AND A TROPICAL DEPRESSION COULD FORM NEAR OR EAST OF
THE LESSER ANTILLES BY THE END OF NEXT WEEK. THERE IS A MEDIUM
CHANCE OF TROPICAL DEVELOPMENT WITHIN THE NEXT 7 DAYS.
A CENTRAL ATLANTIC TROPICAL WAVE IS RELOCATED EASTWARD TO NEAR 39W
FROM 20N SOUTHWARD. IT IS MOVING WEST AT 5 TO 10 KT. DRYNESS AT
LOW TO MID LEVELS ARE PROHIBITING SIGNIFICANT CONVECTION NEAR THIS
WAVE.
ANOTHER TROPICAL WAVE IS EAST OF THE LESSER ANTILLES NEAR 54W FROM
20N SOUTHWARD, AND MOVING WEST AROUND 5 KT. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE NOTED E OF THE WAVE AXIS FROM 10N TO
18N BETWEEN 46W AND 54W.
..MONSOON TROUGH/ITCZ
THE MONSOON TROUGH ENTERS THE ATLANTIC OCEAN ALONG THE SENEGAL
COAST NEAR 14N17W, THEN CONTINUES WESTWARD TO 09N40W. THE ITCZ
EXTENDS FROM 09N40W TO 11N50W. SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION IS PRESENT FROM 03N TO 10N BETWEEN 18W AND 30W,
AND FROM 10N TO 14N BETWEEN 20W AND 24W.
..GULF OF AMERICA
TWO SURFACE TROUGHS ARE CREATING NUMEROUS SHOWERS, WITH EMBEDDED
THUNDERSTORMS, ACROSS THE CENTRAL AND EASTERN BAY OF CAMPECHE,
AND ACROSS THE NORTH-CENTRAL GULF. SIMILAR CONVECTIVE ACTIVITY
HAS FLARED-UP OVER THE YUCATAN PENINSULA. FRESH TO STRONG NE TO E
WINDS, AND MODERATE SEAS DOMINATE THE NE AND N-CENTRAL GULF DUE
TO THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE SE OF THE
UNITED STATES AND A SURFACE TROUGH LOCATED N OF 25N AND NEAR
90W. FRESH TO LOCALLY STRONG NW WINDS AND SEAS OF 4 TO 6 FT ARE
OCCURRING NEAR AND OFFSHORE OF VERACRUZ, MEXICO. GENTLE TO
MODERATE WINDS AND SLIGHT TO MODERATE SEAS PREVAIL ELSEWHERE.
FOR THE FORECAST, FRESH TO STRONG NE TO E WINDS AND LOCALLY ROUGH
SEAS WILL OCCUR OVER THE NORTHERN GULF, MAINLY NORTH OF 25N,
TONIGHT INTO EARLY SUN AS A STRONG PRESSURE GRADIENT PREVAILS
BETWEEN HIGH PRESSURE TO THE NORTH AND A LOW PRESSURE SYSTEM
MEANDERING NEAR THE BAHAMAS AND FLORIDA PENINSULA. A WARM FRONT
IS EXPECTED TO DEVELOP IN THE CENTRAL GULF ON SUN AND LIFT
NORTHWARD INTO THE SOUTHEASTERN UNITED STATES, SUPPORTING SLOWLY
DIMINISHING WINDS OVER THE NORTHERN BASIN, AND MODERATE E TO SE
WINDS AND SLIGHT TO MODERATE SEAS OVER THE REST OF THE GULF INTO
NEXT WEEK. ELSEWHERE, FRESH TO LOCALLY STRONG N TO NW WINDS WILL
OCCUR OFFSHORE OF VERACRUZ THROUGH THIS EVENING.
..CARIBBEAN SEA
A WEAK PRESSURE GRADIENT DOMINATES THE CARIBBEAN SEA SUPPORTING
MODERATE TO LOCALLY FRESH TRADES ACROSS THE SOUTH-CENTRAL
CARIBBEAN, AND GENTLE TO MODERATE WINDS ELSEWHERE. SLIGHT TO
MODERATE SEAS ARE WITHIN THESE WINDS. HIGHER SEAS OF 6 TO 7 FT IN
N SWELL ARE NOTED ACROSS THE NE ATLANTIC PASSAGES, INCLUDING THE
MONA AND ANEGADA PASSES. AN UPPER-LEVEL LOW IS SPINNING OVER
HISPANIOLA, WITH AN UPPER-LEVEL TROUGH EXTENDING TO EASTERN
PANAMA. THESE FEATURES ARE ENHANCING CONVECTION OVER MOST OF THE
WESTERN HALF OF THE BASIN, INCLUDING HISPANIOLA, JAMAICA AND CUBA
AS WELL AS PARTS OF THE SOUTH-CENTRAL CARIBBEAN AND CENTRAL
AMERICA.
FOR THE FORECAST, GENTLE TO MODERATE TRADE WINDS WILL PREVAIL
OVER MUCH OF THE CARIBBEAN SEA INTO NEXT WEEK. A LONG-PERIOD N TO
NE SWELL, GENERATED BY PREVIOUS TROPICAL CYCLONES IMELDA AND
HUMBERTO, WILL LEAD TO ROUGH SEAS IN THE ATLANTIC PASSAGES AND
OVER THE WATERS EAST OF THE LESSER ANTILLES TONIGHT INTO EARLY
NEXT WEEK, WITH MODERATE SEAS EXPANDING OVER THE EASTERN CARIBBEAN
TONIGHT. SEAS WILL SLOWLY SUBSIDE EARLY NEXT WEEK. LOOKING AHEAD,
MODERATE TO OCCASIONALLY FRESH E TO SE WINDS WILL PULSE IN THE
GULF OF HONDURAS SAT NIGHT INTO EARLY NEXT WEEK.
..ATLANTIC OCEAN
PLEASE READ THE SPECIAL FEATURES SECTION AT THE VERY BEGINNING ABOUT
LARGE NORTHERLY SWELL.
A COLD FRONT ENTERS THE FORECAST AREA NEAR 31N48W, THEN CONTINUES
SW TO NEAR 24N58W WHERE IT BECOMES A STATIONARY FRONT THAT EXTENDS
TO A 1011 MB LOW PRESSURE LOCATED OVER THE CENTRAL BAHAMAS. SCATTERED
SHOWERS AND THUNDERSTORMS ARE NEAR THE FRONT, MORE CONCENTRATED
NEAR THE LOW PRESSURE CENTER. FRESH TO STRONG SW WINDS ARE N OF
25N AND E OF THE FRONT TO ABOUT 43W. SIMILAR WIND SPEEDS ARE N
OF THE FRONTAL BOUNDARY. VERY ROUGH SEAS, IN NORTHERLY SWELL,
FOLLOW THE FRONT. HIGH PRESSURE DOMINATES THE WESTERN ATLANTIC IN
THE WAKE OF THE FRONT. FARTHER EAST, A SURFACE TROUGH RUNS FROM
27N26W TO 18N31W, AND IT IS GENERATING SOME CONVECTIVE ACTIVITY,
MAINLY NEAR THE NORTHERN END OF THE TROUGH AXIS. GENTLE TO
MODERATE WINDS ARE OBSERVED OVER THE TROPICAL ATLANTIC.
FOR THE FORECAST WEST OF 55W, FRESH TO STRONG NE WINDS WILL OCCUR
OFF THE COAST OF FLORIDA AND OVER THE NORTHERN BAHAMAS, GENERALLY
NORTH OF 25N AND WEST OF 70W, TONIGHT INTO EARLY NEXT WEEK AS A
WEAK AREA OF LOW PRESSURE MEANDERS NEAR THE BAHAMAS AND FLORIDA
OVER THE NEXT SEVERAL DAYS. THERE IS A LOW CHANCE OF TROPICAL
DEVELOPMENT WITH THIS SYSTEM OVER THE NEXT 48 HOURS. FARTHER
EAST, STRONG WINDS ARE EXPECTED EAST OF A COLD FRONT IN THE
CENTRAL ATLANTIC INTO EARLY SAT, WITH FRESH N TO NE WINDS
OCCURRING IN THE WAKE OF THE FRONT. THE FRONT WILL LIFT NORTHWARD
AND WEAKEN THIS WEEKEND. LARGE N SWELL GENERATED BY PREVIOUS
TROPICAL CYCLONES IMELDA AND HUMBERTO WILL CONTINUE TO EXPAND
SOUTHEASTWARD THIS WEEKEND LEADING TO WIDESPREAD ROUGH SEAS
NORTH OF 10N.
GR
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