235
AXNT20 KNHC 152028
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0015 UTC TUE DEC 16 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
2000 UTC.
..SPECIAL FEATURES
WESTERN ATLANTIC SIGNIFICANT SWELL EVENT: AN ARCTIC COLD FRONT
EXTENDS FROM NEAR 31N62W TO THE CENTRAL BAHAMAS AND TO THE
SOUTHERN STRAITS OF FLORIDA. STRONG HIGH PRESSURE IS BUILDING IN
BEHIND THE FRONT. GALE-FORCE WINDS THAT WERE OVER THE WATERS N OF
30N AND W OF THE FRONT TO 73W HAVE DIMINISHED BELOW GALE-FORCE
WHILE GALE-FORCE WINDS PERSIST N OF 31N. THIS SYSTEM AND THE
ASSOCIATED WINDS CONTINUE TO SUPPORT LARGE, FRESH NORTHERLY
SWELLS OF 12-17 FT W OF THE FRONT AND HIGHER N OF 31N WITH WAVE
PERIODS OF 8-11 SECONDS. THE LARGE NORTHERLY SWELL WILL REACH THE
ISLANDS OF THE NORTHEAST CARIBBEAN LATE TUE NIGHT INTO EARLY WED
AS IT MERGES WITH EASTERLY TRADE WIND SWELL MOVING THROUGH THE
REGIONAL WATERS. SEAS WILL BEGIN TO GRADUALLY SUBSIDE FROM NW TO
SE DURING THE MIDDLE OF THE WEEK. PLEASE READ THE LATEST HIGH SEAS
FORECAST ISSUED BY THE NATIONAL HURRICANE CENTER AT WEBSITE
HTTPS://WWW.NHC.NOAA.GOV/TEXT/MIAHSFAT2.SHTML FOR MORE
INFORMATION.
EAST ATLANTIC SIGNIFICANT SWELL EVENT: LARGE, LONG-PERIOD NORTH
TO NORTHEAST SWELL MIXED WITH NORTHWEST SWELL CONTINUES TO AFFECT
MOST OF THE EASTERN TROPICAL AND SUBTROPICAL ATLANTIC. SEAS OF 12
FT OR GREATER ARE CURRENTLY FROM 05N TO 24N BETWEEN 30W AND 53W,
PEAKING AROUND 13 FT PER RECENT SATELLITE ALTIMETER DATA. GLOBAL
WAVE MODELS SHOW NORTHERLY SWELL OF 14 TO 16 SECONDS MIXING WITH
NORTHEAST SWELL OF 9 TO 10 SECONDS ACROSS THIS AREA. WITH
PERSISTENT FRESH TO STRONG NORTHEAST TRADE WINDS, THE AREA OF 12
FT OR GREATER SEAS WILL EXPAND WESTWARD TO NEAR 50W TONIGHT BEFORE
THEY SLOWLY SUBSIDE FROM NE TO SW GOING INTO TUE. FOR INFORMATION
EAST OF 35W PLEASE READ THE LATEST HIGH SEAS FORECAST ISSUED BY
METEO-FRANCE AT WEBSITE:
HTTPS://WWMIWS.WMO.INT/INDEX.PHP/METAREAS/AFFICHE/2. FOR
INFORMATION WEST OF 35W, PLEASE READ THE LATEST HIGH SEAS
FORECAST ISSUED BY THE NATIONAL HURRICANE CENTER AT WEBSITE:
HTTPS://WWW.NHC.NOAA.GOV/TEXT/MIAHSFAT2.SHTML.
..MONSOON TROUGH/ITCZ
THE MONSOON TROUGH AXIS ENTERS THE ATLANTIC NEAR 07N12W AND
CONTINUES SOUTHWESTWARD TO 05N20W, WHERE IT TRANSITIONS TO THE
ITCZ TO 03.5N35W TO THE COAST OF BRAZIL NEAR 03.5N51W. NUMEROUS
MODERATE TO ISOLATED STRONG CONVECTION IS SEEN FROM 01N TO 08.5N
EAST OF 20W TO INLAND OVER PORTIONS OF WESTERN AFRICA. SCATTERED
MODERATE CONVECTION IS SEEN FROM S OF 05N BETWEEN 20W AND 37W.
..GULF OF AMERICA
AN ARCTIC COLD FRONT CONTINUES TO PUSH SOUTHWARD FROM THE SOUTHERN
STRAITS OF FLORIDA TO ALONG THE NW COAST OF CUBA TO THE YUCATAN
CHANNEL AND NORTHERN PORTION OF THE YUCATAN PENINSULA TO THE
SOUTHERN BAY OF CAMPECHE. A TIGHT PRESSURE GRADIENT REMAINS ALONG
AND OFFSHORE OF TAMAULIPAS AND VERACRUZ WHERE FRESH TO NEAR GALE-
FORCE NW-N WINDS ARE WITH MODERATE TO FRESH N-NE WINDS ELSEWHERE
ACROSS THE BASIN AND BEHIND THE FRONT. SEAS ARE 7-11 FT FROM 21N
TO 27N PER RECENT ALTIMETER AND BUOY OBSERVATIONS WITH MAINLY 3-6
FT SEAS ELSEWHERE.
FOR THE FORECAST, A COLD FRONT OVER THE SOUTHEAST GULF WILL EXIT
THE BASIN TONIGHT. STRONG NORTHERLY WINDS AND ROUGH SEAS FOLLOWING
THE FRONT WILL DECREASE BY MIDWEEK. HIGH PRESSURE WILL DOMINATE
THE GULF REGION IN THE WAKE OF THE FRONT TUE THROUGH THU. THE NEXT
COLD FRONT IS EXPECTED TO MOVE INTO THE NW GULF THU EVENING AND
REACH FROM NEAR TAMPA BAY TO SE TEXAS FRI EVENING THEN LIFT
NORTHWARD AND DISSIPATE.
..CARIBBEAN SEA
A STRONG ARCTIC COLD FRONT IS MOVING THROUGH THE WESTERN
ATLANTIC, WITH A LARGE AREA OF STRONG HIGH PRESSURE BUILDING IN
BEHIND. THE FRONT IS NEAR THE NW PORTION OF THE BASIN ALONG NW
CUBA AND THE YUCATAN CHANNEL TO THE NORTHERN YUCATAN PENINSULA.
THIS FRONT HAS WEAKENED THE PRESSURE GRADIENT SLIGHTLY AHEAD OF IT
WITH MAINLY MODERATE TO FRESH TRADES NOTED ACROSS MOST OF THE
BASIN, HIGHEST IN THE S-CENTRAL PORTION WHERE THE PRESSURE
GRADIENT IS THE TIGHTEST DUE TO LOW PRESSURE NEAR THE NORTHERN
COAST OF COLOMBIA. SEAS ARE 5-7 FT IN THE CENTRAL CARIBBEAN DUE TO
THE PERSISTENT FETCH OF THE TRADES, AND 4-6 FT ELSEWHERE EXCEPT
SLIGHTLY LOWER BETWEEN CUBA AND JAMAICA INCLUDING THE APPROACH TO
THE WINDWARD PASSAGE. NUMEROUS MODERATE TO ISOLATED STRONG
CONVECTION IS CONFINED TO THE FAR SOUTHWESTERN SECTION OF THE SEA,
S OF ABOUT 12N AND W OF COLOMBIA DUE TO THE COMBINATION OF LOW-
LEVEL CONVERGENCE OF THE TRADE WINDS ALONG WITH INSTABILITY
PROVIDED BY THE CLOSE PROXIMITY OF THE EASTERN PACIFIC OCEAN
MONSOON TROUGH THAT EXTENDS EASTWARD ACROSS SOUTHERN COSTA RICA
AND ACROSS PANAMA. SIMILAR CONVECTION IS ALSO NOTED IN THE GULF OF
HONDURAS DUE TO DEEP LAYERED TROUGHING AHEAD OF THE FRONT ALONG
WITH UPPER LEVEL DIFFLUENCE OFF TO THE SE.
FOR THE FORECAST, FRESH TRADE WINDS AND MODERATE SEAS WILL
PREVAIL OVER THE SOUTH CENTRAL CARIBBEAN THROUGH TUE AS ATLANTIC
HIGH PRESSURE REMAINS WELL NE OF THE REGION. ELSEWHERE, FRESH TO
LOCALLY STRONG TRADE WINDS AND ROUGH SEAS IN LARGE E SWELL WILL
PERSIST OVER THE TROPICAL ATLANTIC WATERS, THROUGH THE ATLANTIC
PASSAGES AND INTO THE EASTERN PART OF THE BASIN THROUGH TUE. A
COLD FRONT WILL ENTER THE NORTHWESTERN CARIBBEAN THIS EVENING,
ACCOMPANIED BY INCREASING WINDS AND BUILDING SEAS. THIS FRONT IS
EXPECTED TO REACH FROM CENTRAL CUBA TO N BELIZE TUE MORNING, THEN
WILL STALL AND GRADUALLY DISSIPATE THROUGH WED. HIGH PRESSURE WILL
BUILD INTO THE W ATLANTIC WED THROUGH FRI TO BRING A RETURN TO
FRESH TO STRONG TRADES ACROSS THE CENTRAL CARIBBEAN.
..ATLANTIC OCEAN
PLEASE SEE THE SPECIAL FEATURES SECTION FOR MORE INFORMATION ON
TWO SIGNIFICANT SWELL EVENTS, ONE FOR A PORTION OF THE NORTHWEST
ATLANTIC WATERS, AND THE OTHER IN THE EASTERN ATLANTIC.
AN ARCTIC COLD FRONT EXTENDS FROM NEAR 31N62W TO THE CENTRAL
BAHAMAS AND TO THE SOUTHERN STRAITS OF FLORIDA. IN ADDITION TO THE
ABOVE MENTIONED SWELL BEHIND THE FRONT, FRESH TO STRONG N-NE WINDS
ARE ALSO PRESENT. N OF 29N AND E OF THE FRONT TO 50W, FRESH TO
STRONG S-SW WINDS ARE PRESENT AHEAD OF THE FRONT. SCATTERED
MODERATE CONVECTION IS NOTED ON CONVENTIONAL SATELLITE IMAGERY N
OF 26N AND E OF THE FRONT TO 52W. HIGH PRESSURE OF 1030 MB IS N OF
THE AREA NEAR THE AZORES, WITH AN ASSOCIATED RIDGE BRIDGING ACROSS
A FRONT THAT EXTENDS FROM THE IBERIAN PENINSULA THROUGH 31N17W TO
28N26.5W TO 31N34W. THIS HIGH COMBINED WITH LOWER PRESSURES TO THE
S WITH THE MONSOON TROUGH AND ITCZ SUPPORTS A LARGE AREA OF FRESH
TO STRONG TRADES S OF 26N AND E OF 53W WHERE LARGE SWELLS ARE
PRESENT AS DETAILED ABOVE. FRESH TO STRONG N-NE WINDS ARE ALSO
NOTED N OF THE FRONT. MAINLY MODERATE WINDS AND 6-10 FT SEAS ARE
PRESENT ACROSS THE REMAINDER OF THE OPEN WATERS, EXCEPT GENTLE
WINDS AND 5-8 FT SEAS S OF 29N AND W OF 60W TO THE ARCTIC COLD
FRONT.
FOR THE FORECAST W OF 55W, A COLD FRONT EXTENDS FROM NEAR 31N62W
TO W CUBA. STRONG TO NEAR GALE- FORCE NORTHERLY WINDS WILL
DIMINISH TONIGHT. THE FRONT WILL STALL FROM 30N55W TO THE SE
BAHAMAS AND CENTRAL CUBA BY TUE MORNING, THEN SLOWLY DISSIPATE
THROUGH WED AFTERNOON. LARGE N SWELL WILL BUILD ACROSS THE
REGIONAL WATERS BEHIND THE FRONT THROUGH TUE BEFORE SUBSIDING. THE
BERMUDA HIGH WILL DOMINATE THE REGIONAL WATERS THU THROUGH FRI.
LEWITSKY
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