781
AXNT20 KNHC 120450
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0615 UTC SAT SEP 12 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
0430 UTC.
..TROPICAL WAVES
THE AXIS OF A TROPICAL WAVE IS NEAR 37W-38W, SOUTH OF 24N, MOVING
WESTWARD AT 15 TO 20 KT. THE PORTIONS OF THE WAVE N OF 18N IS
SHIFTING NORTHWESTWARD, FORCED BY MIDDLE LEVEL SOUTHEASTERLY FLOW
BEHIND IT. SCATTERED MODERATE CONVECTION IS FROM 21N TO 25N NEAR
THIS PORTION OF THE WAVE. SCATTERED MODERATE CONVECTION IS ALSO
ABOUT THE SOUTHERN PORTION OF THE WAVE, FROM 07.5N TO 12N BETWEEN
34W AND 44W.
A TROPICAL WAVE PREVIOUSLY ANALYZED OVER THE CENTRAL CARIBBEAN
ALONG 76W IS NO LONGER CLEARLY EVIDENT, AND HAS BEEN DROPPED FROM
THE 00Z ANALYSIS. HOWEVER, A WIND SURGE IS SUGGESTED ACROSS THAT
AREA, AND IS APPROACHING THE NEXT TROPICAL WAVE ACROSS THE
WESTERN CARIBBEAN.
A SECOND TROPICAL WAVE IS OVER THE NW CARIBBEAN NEAR 85W-86W,
SOUTH OF 20N, MOVING WESTWARD AT 15 TO 20 KT. SCATTERED TO
LOCALLY NUMEROUS SQUALLS AND THUNDERSTORMS ARE ACROSS THE NW BASIN
AND GULF OF HONDURAS, FROM 15.5N TO 20.5N BETWEEN 78W AND 86W.
SCATTERED MODERATE CONVECTION IS NOTED ABOUT THE EASTERN PACIFIC
MONSOON TROUGH AND CENTRAL AMERICA AND INTO THE EASTERN PACIFIC
WATERS, AFFECTING PARTS OF HONDURAS, NICARAGUA. COSTA RICA AND
PANAMA.
..MONSOON TROUGH/ITCZ
THE MONSOON TROUGH ENTERS THE ATLANTIC THROUGH THE COAST OF
SENEGAL NEAR 14N17W, AND CONTINUES TO 09N21W TO 13N32W TO 11N39W.
THE ITCZ EXTENDS FROM 10.5N43W TO THE COAST OF VENEZUELA NEAR
08.5N61W. ASIDE FROM CONVECTION ASSOCIATED WITH THE TROPICAL
WAVE, NUMEROUS MODERATE TO STRONG CONVECTION IS NOTED FROM 09N TO
12N BETWEEN 47W AND 61W.
..GULF OF AMERICA
EVENING CONVECTION ACROSS THE BASIN HAS DIMINISHED SIGNIFICANTLY
IN RECENT HOURS, WITH SCATTERED MODERATE CONVECTION CONTINUING
ACROSS THE FLORIDA BIG BEND N OF 27N. A VERY WEAK PRESSURE PATTERN
PREVAILS ACROSS THE GULF BASIN, WITH 1017 MB HIGH PRESSURE OVER
NORTH-CENTRAL FLORIDA YIELDING A GENERALLY LIGHT TO GENTLE
ANTICYCLONIC WIND FLOW. MODERATE E TO NE WINDS PREVAIL ACROSS NW
AND W COASTAL WATERS OF THE YUCATAN PENINSULA, AHEAD OF THE
TYPICAL SURFACE TROUGH OVER THE PENINSULA, WHILE MODERATE TO
LOCALLY FRESH WINDS ARE NEAR THE COAST OF NORTHEASTERN MEXICO AND
SOUTH TEXAS. SEAS ARE 3 FT OR LESS BASIN-WIDE, EXCEPT 3-5 FT
WITHIN 120 NM OF THE COASTS OF NORTHEASTERN MEXICO AND SOUTH
TEXAS.
FOR THE FORECAST, HIGH PRESSURE WILL PREVAIL ACROSS THE NE GULF
WATERS DURING THE NEXT SEVERAL DAYS. WINDS WILL PULSE TO FRESH
SPEEDS EACH NIGHT OFF THE W YUCATAN PENINSULA DUE TO A DIURNAL
TROUGH MOVING TOWARD THE SW GULF. BY THE MIDDLE OF NEXT WEEK, A
BUILDING RIDGE OVER THE EASTERN UNITED STATES AND A FRONTAL TROUGH
WILL COMBINE TO INCREASE WINDS TO FRESH SPEEDS OVER THE GULF
WATERS N OF 23N.
..CARIBBEAN SEA
WEAK HIGH PRESSURE IS CENTERED N OF THE BASIN, BETWEEN THE BAHAMAS
AND BERMUDA. THE PRESSURE GRADIENT BETWEEN THE ASSOCIATED RIDGE
AND THE COLOMBIAN LOW SUPPORTS FRESH TO STRONG TRADE WINDS AND
ROUGH SEAS OVER MUCH OF THE CENTRAL CARIBBEAN S OF 18N, AS NOTED
IN RECENT SATELLITE SCATTEROMETER DATA. SEAS ARE 8 TO 11 FT S OF
17N OVER THE SOUTH- CENTRAL CARIBBEAN. ELSEWHERE MODERATE TO
LOCALLY FRESH TRADE WINDS AND MODERATE SEAS ARE EVIDENT, WITH THE
EXCEPTION OF LIGHT TO GENTLE WINDS OVER THE NW CARIBBEAN. AN
UPPER-LEVEL TROUGH OVER THE NW CARIBBEAN IS ENHANCING CONVECTIVE
ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE ACROSS THE WESTERN
BASIN. FAIR WEATHER PREVAILS ACROSS THE AREA E OF 78W.
FOR THE FORECAST, THE PRESSURE GRADIENT BETWEEN THE SUBTROPICAL
RIDGE NORTH OF THE AREA AND LOWER PRESSURES ASSOCIATED WITH THE
COLOMBIAN LOW WILL CONTINUE TO FORCE STRONG TO LOCALLY NEAR-GALE
EASTERLY TRADE WINDS AND ROUGH TO LOCALLY VERY ROUGH SEAS OVER THE
CENTRAL CARIBBEAN FOR THE NEXT SEVERAL DAYS. MEANWHILE, MODERATE
TO FRESH EASTERLY BREEZES ARE EXPECTED OVER THE NEXT FEW DAYS IN
THE EASTERN CARIBBEAN. WINDS WILL PULSE TO STRONG SPEEDS IN THE
GULF OF HONDURAS LATE SAT THROUGH MON MORNING. ELSEWHERE, MODERATE
OR WEAKER WINDS AND SLIGHT TO MODERATE SEAS WILL BE PREVALENT.
..ATLANTIC OCEAN
A FRONTAL TROUGH EXTENDS FROM 31N44.5W TO 25N53W TO 31N64W. UPPER
LEVEL LOW PRESSURE LOCATED E OF THE SOUTHEAST BAHAMAS IS
SUPPORTINGSCATTERED SHOWERS AND THUNDERSTORMS S OF THIS TROUGH,
FROM 24.5N TO 28.5N BETWEEN 55W AND 73W. THE REMAINDER OF THE
FORECAST WATERS ARE DOMINATED BY HIGH PRESSURE, WITH A 1026 MB
HIGH CENTER OF 1023 MB LOCATED OFFSHORE OF NW SPAIN, AND 1018 MB
HIGH NEAR 28N69W. THE PRESSURE GRADIENT BETWEEN THE EASTERN
ATLANTIC HIGH PRESSURE AND LOWER PRESSURES OVER NW AFRICA IS
PROMOTING MODERATE TO FRESH N TO NE WINDS N OF 16N AND E OF 22W,
INCLUDING THE CANARY ISLANDS. MODERATE TO FRESH TRADE WINDS ARE
OBSERVED E OF THE LESSER ANTILLES TO ABOUT 50W, WHERE SEAS ARE 5
TO 7 FT, AND ALSO ALONG THE N COAST OF HISPANIOLA. MODERATE OR
WEAKER WINDS PREVAIL ELSEWHERE. SEAS ARE, IN GENERAL, MODERATE
ACROSS THE ATLANTIC FORECAST WATERS.
FOR THE FORECAST WEST OF 55W, THE SUBTROPICAL RIDGE WILL DOMINATE
THE SW N ATLANTIC WATERS OVER THE NEXT SEVERAL DAYS. TRADES NORTH
OF HISPANIOLA INTO THE WINDWARD PASSAGE WILL BE FRESH TO LOCALLY
STRONG THROUGH EARLY NEXT WEEK. LOOKING AHEAD, A BUILDING RIDGE
OVER THE EASTERN UNITED STATES AND A FRONTAL TROUGH WILL COMBINE
TO INCREASE WINDS TO FRESH SPEEDS AND BUILD SEAS TO LOCALLY ROUGH
NORTH OF THE BAHAMAS AND W OF 70W STARTING EARLY NEXT WEEK AND
CONTINUING THROUGH WED NIGHT. ELSEWHERE, MODERATE OR WEAKER WINDS
AND SLIGHT TO MODERATE SEAS WILL PREVAIL.
STRIPLING
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