949
AXNT20 KNHC 130410
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0615 UTC SUN SEP 13 2026
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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0330 UTC.
..SPECIAL FEATURES
CARIBBEAN GALE WARNING: A TIGHT PRESSURE GRADIENT BETWEEN THE
WESTERN ATLANTIC SUBTROPICAL RIDGE CENTERED ALONG 71W AND LOWER
PRESSURES ASSOCIATED WITH THE COLOMBIAN LOW SUPPORTS FRESH TO
STRONG WINDS ACROSS A LARGE PORTION OF THE CENTRAL CARIBBEAN
TONIGHT. WINDS HAVE INCREASED TO GALE-FORCE OFF THE COAST OF
COLOMBIA S OF 12.5N, WHERE SEAS ARE 11-12 FT. WINDS THERE WILL
DIMINISH BELOW GALE-FORCE BY SUNRISE. THIS PATTERN IS EXPECTED TO
CONTINUE FOR THE NEXT SEVERAL DAYS, AND MAINTAIN THESE ROUGH
MARINE CONDITIONS. A GALE WARNING HAS BEEN ISSUED FOR THE WATERS
OFF OF COLOMBIA THROUGH 0900 UTC.
PLEASE READ THE LATEST HIGH SEAS FORECAST ISSUED BY THE NATIONAL
HURRICANE CENTER AT WEBSITE:
HTTPS://WWW.NHC.NOAA.GOV/TEXT/MIAHSFAT2.SHTML
..TROPICAL WAVES
AN ATLANTIC TROPICAL WAVE HAS BEEN ADDED TO THE 0000 UTC SURFACE
ANALYSIS ALONG 38W/39W, SOUTH OF 16N, MOVING WESTWARD NEAR 20 KT.
LATEST SATELLITE IMAGERY, PRECIPITABLE WATER, AND SCATTEROMETER
DATA DEPICT THIS WAVE. SCATTERED MODERATE ISOLATED STRONG
CONVECTION IS NOTED FROM 06N TO 15N BETWEEN 36W AND 41.5W.
THE AXIS OF A TROPICAL WAVE IS NEAR 45W, FROM 08N TO 18N, MOVING
WESTWARD NEAR 20 KT. WIDELY SCATTERED MODERATE CONVECTION IS SEEN
NEAR THE WAVE AXIS BETWEEN 42W AND 46W.
..MONSOON TROUGH/ITCZ
THE MONSOON TROUGH ENTERS THE ATLANTIC THROUGH THE COAST OF
GUENIA-BISSAU NEAR 12N16.5W, AND CONTINUES TO 08N26W TO 11N39W TO
10.5N44W. THE ITCZ EXTENDS FROM 10N46W TO THE COAST OF NE
VENEZUELA NEAR 10.5N63W. BEYOND WEATHER DESCRIBED WITH TROPICAL
WAVES, SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED
FROM 05.5N TO 10N BETWEEN 14W AND 33W, AND FROM 09N AND 12.5N
BETWEEN 46W AND 55W.
..GULF OF AMERICA
CONVECTION HAS DIMINISHED SIGNIFICANTLY ACROSS THE NORTHERN GULF
EARLY TONIGHT. SCATTERED MODERATE ISOLATED STRONG CONVECTION
CONTINUES WITHIN 75 NM OF THE W COAST OF FLORIDA FROM CEDAR KEY TO
THE FLORIDA KEYS. AND THEN ACROSS THE YUCATAN CHANNEL. A STRONG
CONVECTIVE CLUSTER IS SHIFTING OFF THE WESTERN COAST OF THE
YUCATAN CHANNEL AND INTO THE EASTERN BAY OF CAMPECHE. WEAK HIGH
PRESSURE PERSISTS OVER THE NE GULF AND IS PROMOTING GENERALLY
LIGHT TO MODERATE ANTICYCLONIC FLOW ACROSS THE BASIN, WITH SEAS OF
3 FT OR LESS. MODERATE TO FRESH NE WINDS PREVAIL ALONG THE NW AND
W COASTS OF THE YUCATAN, WHILE MODERATE SE WINDS PREVAIL ACROSS
THE COASTAL WATERS OF NE MEXICO AND SOUTHERN TEXAS, WHERE SEAS ARE 3
TO 4 FT.
FOR THE FORECAST, WEAK HIGH PRESSURE WILL MAINTAIN RELATIVELY
TRANQUIL CONDITIONS ACROSS GULF WATERS INTO THE START OF NEXT
WEEK. THE EXCEPTION WILL BE THE BAY OF CAMPECHE, WHERE A DIURNAL
TROUGH WILL MOVE WESTWARD OFFSHORE THE YUCATAN PENINSULA EACH
EVENING, BRINGING NIGHTLY PULSES OF FRESH NE WINDS FOLLOWED BY
SHOWERS AND THUNDERSTORMS. STARTING LATER TUE, STRONGER HIGH
PRESSURE BUILDING SOUTHWARD FROM THE EASTERN UNITED STATES WILL
LEAD TO INCREASING NE TO E WINDS OVER THE BASIN, WITH SPEEDS
REACHING FRESH TO STRONG OVER THE NE BASIN WED AND THU. CONDITIONS
WILL IMPROVE LATE NEXT WEEK.
..CARIBBEAN SEA
AS PREVIOUSLY MENTIONED, THE PRESSURE GRADIENT BETWEEN SURFACE
RIDGING OVER THE WESTERN ATLANTIC AND THE COLOMBIAN LOW SUPPORTS
FRESH TO STRONG EASTERLY TRADE WINDS AND ROUGH SEAS OVER MUCH OF
THE CENTRAL CARIBBEAN, S OF 18N BETWEEN 64W AND 81W. FRESH TO
STRONG WINDS AND SEAS TO 6 FT ARE FOUND ACROSS THE GULF OF
HONDURAS S OF 17N. MODERATE TO FRESH EASTERLY WINDS AND MODERATE
SEAS ARE FOUND IN THE EASTERN CARIBBEAN E OF 64W, WHILE MODERATE
OR WEAKER WINDS AND SLIGHT SEAS ARE PREVALENT ELSEWHERE. AN UPPER-
LEVEL TROUGH OVER THE NW CARIBBEAN IS HELPING TO SUSTAIN
CONVECTION OVER HAITI, AND THE NW CARIBBEAN BETWEEN JAMAICA AND
CENTRAL CUBA. SCATTERED SHOWERS AND THUNDERSTORMS ARE NOTED OVER
THE WESTERN BASIN FROM THE YUCATAN CHANNEL TO THE GULF OF
HONDURAS, AND ACROSS THE COASTAL WATERS OF PANAMA, COSTA RICAN AND
NICARAGUA.
FOR THE FORECAST, THE PRESSURE GRADIENT BETWEEN THE WESTERN
ATLANTIC SUBTROPICAL RIDGE AND LOWER PRESSURES ASSOCIATED WITH
THE COLOMBIAN LOW HAS INCREASED IN THE PAST 24 HOURS, AS THE MOST
RECENT TROPICAL WAVE HAS EXITED THE EASTERN CARIBBEAN AND MOVED
INTO THE EASTERN PACIFIC. THIS PATTERN WILL CONTINUE TO SUPPORT
STRONG TO NEAR-GALE EASTERLY TRADE WINDS AND ROUGH TO LOCALLY
VERY ROUGH SEAS OVER THE CENTRAL CARIBBEAN FOR THE NEXT SEVERAL
DAYS. WINDS WILL PULSE TO GALE FORCE TONIGHT OFFSHORE COLOMBIA,
THEN DIMINISH BY SUNRISE. STRONG WINDS ARE EXPECTED TONIGHT AND
SUN NIGHT IN THE GULF OF HONDURAS. MEANWHILE, MODERATE TO FRESH
EASTERLY BREEZES ARE EXPECTED OVER THE NEXT FEW DAYS IN THE
EASTERN CARIBBEAN.
..ATLANTIC OCEAN
A DEEP LAYERED UPPER-LEVEL TROUGH EXTENDS FROM THE CENTRAL
ATLANTIC NEAR 33N41W SOUTHWESTWARD TO N OF HISPANIOLA TO NEAR
JAMAICA, AND IS SUPPORTING SEVERAL AREAS OF SIGNIFICANT CONVECTION
ACROSS THE BASIN TONIGHT. A BAND OF SHOWERS AND THUNDERSTORMS
COVERS THE AREA FROM 23N TO 26.5N BETWEEN 61W AND 72W. A LOW TO
MIDDLE LEVEL TROUGH ALONG ABOUT 42W FROM 20N TO 28N IS FAVORABLY
INTERACTING WITH THIS UPPER TROUGH TO PRODUCE SCATTERED SHOWERS
AND THUNDERSTORMS FROM 22N TO 30N BETWEEN 38W AND 43W. AT THE
SURFACE 1020 MB HIGH PRESSURE IS CENTERED NEAR 31N71W AND IS
PRODUCING ANTICYCLONIC FLOW N OF 25N AND W OF 65W. A LINGERING
SURFACE TROUGH FROM THE STRAITS OF FLORIDA TO NEAR 30N77W IS
HELPING TO FOCUS SCATTERED THUNDERSTORMS THAT HAVE SHIFTED
SOUTHEASTWARD OFF OF SE FLORIDA AND INTO THE COASTAL WATERS
BETWEEN THE NW BAHAMAS TO ACROSS THE FLORIDA KEYS IN THE PAST FEW
HOURS. A PAIR OF WEAK SURFACE TROUGHS N OF 20N BETWEEN 50W AND 65W
AID IN SEPARATING THE WESTERN ATLANTIC RIDGE FROM STRONGER HIGH
PRESSURE ACROSS THE NE AND E ATLANTIC. 1026 MB HIGH PRESSURE
CENTERED NE OF THE AZORES EXTENDS A RIDGE SOUTHWESTWARD TO 30N40W.
THE PRESSURE GRADIENT BETWEEN THIS RIDGE AND LOWER PRESSURE
ACROSS NW AFRICA IS PRODUCING FRESH TO LOCALLY STRONG N TO NE
WINDS FROM OFFSHORE OF EUROPE ALONG 35N THROUGH THE CANARY ISLANDS
TO 25N AND E OF 25W. SEAS ARE 6 TO 9 FT ACROSS THIS AREA. OF
NOTE, A GALE- FORCE EASTERLY GAP WIND EVENT IS OCCURRING IN THE
STRAITS OF GIBRALTAR. ELSEWHERE ACROSS THE TROPICAL ATLANTIC
MODERATE TO LOCALLY FRESH TRADE WINDS PREVAIL S OF 22N BETWEEN 30W
AND THE LESSER ANTILLES. SEAS ARE 4 TO 7 FT ACROSS THIS ZONE. TO
THE NORTH OF THESE TRADES, WINDS ARE MODERATE OR LESS WITH SEAS 4
FT OR LESS.
FOR THE FORECAST WEST OF 55W, THE WESTERN ATLANTIC SUBTROPICAL
RIDGE WILL CONTINUE TO DOMINATE THROUGH MON NIGHT, PRODUCING MAINLY
TRANQUIL MARINE CONDITIONS. HOWEVER, TRADES NORTH OF HISPANIOLA
INTO THE WINDWARD PASSAGE WILL PULSE FRESH TO LOCALLY STRONG INTO
MONDAY. ON TUE, STRONG HIGH PRESSURE BUILDING SE THROUGH THE
EASTERN UNITED STATES WILL BRING A COLD FRONT INTO THE NW WATERS,
INCREASING NE WINDS TO FRESH TO STRONG AND CAUSING SEAS TO BUILD
TO ROUGH N OF THE BAHAMAS AND W OF 70W TUE NIGHT THROUGH WED
NIGHT.
STRIPLING
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