088
AXNT20 KNHC 150402
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0015 UTC TUE SEP 15 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.
..TROPICAL WAVES
A TROPICAL WAVE AXIS IS ALONG 54W, S OF 20N, MOVING WEST AT 10 TO
15 KT. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS DEPICTED
FROM 12N TO 17.5N BETWEEN 50W AND 56W.
..MONSOON TROUGH/ITCZ
THE MONSOON TROUGH ENTERS THE ATLANTIC ALONG THE COAST OF GUINEA
NEAR 10.5N14.5W AND CONTINUES TO 11N21W TO 07.5N43W. THE ITCZ
EXTENDS FROM 09N44W TO 11N54W. NUMEROUS STRONG CONVECTION IS FROM
06N TO 14N E OF 18W TO THE COAST OF AFRICA. SCATTERED MODERATE
CONVECTION IS NOTED FROM 06.5N TO 13N BETWEEN 18W AND 28W, AND
FROM 06.5N TO 12.5N BETWEEN 28W AND 50W.
..GULF OF AMERICA
WIDELY SCATTERED SHOWERS PREVAIL ACROSS THE BASIN FROM 23N TO 28N,
SUPPORTED BY A WEAKENING MIDDLE TO UPPER-LEVEL TROUGH FROM THE
YUCATAN CHANNEL TO SE TEXAS. EVENING CONVECTION ACROSS MUCH OF
INTERIOR FLORIDA CONTINUES TO SHIFT SOUTHWESTWARD AND WEAKEN AS IT
REACHES THE WESTERN COASTAL WATERS OF FLORIDA. AT THE SURFACE, A
1017 MB HIGH PRESSURE CENTER IS JUST OFFSHORE SE LOUISIANA, AND
DOMINATES THE GULF WATERS WITH ANTICYCLONIC FLOW. RECENT
SCATTEROMETER DATA SHOWS LIGHT TO GENTLE WINDS ACROSS THE BASIN E
OF 92W, WHILE FRESH TO LOCALLY STRONG NE WINDS PREVAIL WIHTIN 120
NM OF THE COAST OF THE YUCATAN PENINSULA AND OVER THE EASTERN BAY
OF CAMPECHE, AND MODERATE SE WINDS ARE W OF 95W. SEAS ARE
GENERALLY 3 FT OR LESS, EXCEPT 3-5 FT NEAR THE YUCATAN PENINSULA,
AND 3 TO LOCALLY 4 FT W OF 95W.
FOR THE FORECAST, A WEAK RIDGE CENTERED OVER THE NORETH-CENTRAL
GULF WILL PERSIST INTO TUE SUPPORTING RELATIVELY TRANQUIL MARINE
CONDITIONS ACROSS MUCH OF THE BASIN. THE EXCEPTION WILL BE THE BAY
OF CAMPECHE, WHERE A DIURNAL TROUGH WILL MOVE WESTWARD OFFSHORE
THE YUCATAN PENINSULA EACH EVENING THROUGH LATE THIS WEEK,
BRINGING NIGHTLY PULSES OF FRESH TO LOCALLY STRONG NE WINDS.
STARTING LATE TUE, STRONGER HIGH PRESSURE BUILDING SOUTHWARD FROM
THE EASTERN UNITED STATES, BEHIND A WEAKENING FRONTAL BOUNDARY,
WILL LEAD TO INCREASING NE TO E WINDS OVER THE BASIN, WITH
INCREASING WINDS REACHING FRESH TO LOCALLY STRONG SPEEDS, AND SEAS
BUILDING TO ROUGH OVER THE NORTHERN GULF WED THROUGH THU NIGHT.
CONDITIONS WILL IMPROVE FRI THROUGH SAT.
..CARIBBEAN SEA
A PERSISTENT MIDDLE TO UPPER-LEVEL LOW PRESSURE SYSTEM PREVAILS
ACROSS THE GREATER ANTILLES TONIGHT, AND IS SUPPORTING SCATTERED
MODERATE CONVECTION BETWEEN HAITI AND 80W, AND SCATTERED LIGHT TO
MODERATE CONVECTION ACROSS THE EASTERN CARIBBEAN. AT THE SURFACE,
WEAK HIGH PRESSURE IS CENTERED JUST NORTHEAST OF THE NW BAHAMAS,
AND EXTENDS A RIDGE TO 60W. THE PRESSURE GRADIENT BETWEEN THIS
RIDGE AND LOWER PRESSURES IN COLOMBIA COMBINE TO SUSTAIN FRESH TO
STRONG WITH LOCALLY NEAR GALE-FORCE EASTERLY TRADE WINDS ACROSS
MUCH OF THE CENTRAL CARIBBEAN BETWEEN 68W AND 78W, AS WELL AS THE
WINDWARD PASSAGE. SEAS ARE 6 TO 9 FT ACROSS THIS AREA. ELSEWHERE,
MODERATE TO FRESH TRADES PREVAIL ELSEWHERE, EXCEPT LIGHT WINDS
ACROSS FAR NW PORTIONS. SCATTERED TO LOCALLY NUMEROUS HEAVY
SHOWERS AND THUNDERSTORMS ARE ONGOING OVER THE SW CARIBBEAN
BETWEEN COLOMBIA AND NE NICARAGUA, ALONG THE EASTERN EXTENSION OF
THE E PACIFIC MONSOON THROUGH.
FOR THE FORECAST, THE PRESSURE GRADIENT BETWEEN THE SUBTROPICAL
RIDGE LOCATED NORTH OF THE GREATER ANTILLES AND LOWER PRESSURES
IN COLOMBIA WILL SUPPORT FRESH TO LOCALLY NEAR GALE-FORCE EASTERLY
TRADE WINDS AND MODERATE TO ROUGH SEAS ACROSS MUCH OF THE CENTRAL
CARIBBEAN, WITH MODERATE TO FRESH TRADES ELSEWHERE THROUGH THE
WORKWEEK. EXPECT MODERATE OR LIGHTER WINDS AND SLIGHT TO MODERATE
SEAS ACROSS NW PORTIONS, EXCEPT FOR MODERATE TO FRESH WINDS MAINLY
IN THE EVENINGS NEAR THE WINDWARD PASSAGE AND LEE OF CUBA THROUGH
MIDWEEK. WINDS MAY DIMINISH ACROSS THE BASIN BY THE END OF THE
WEEK INTO THE UPCOMING WEEKEND AS THE PRESSURES GRADIENT RELAXES.
..ATLANTIC OCEAN
A BROAD RIDGE DOMINATES MUCH OF THE ATLANTIC BASIN N OF 10N AND E
OF 60W, PRODUCING MODERATE TO FRESH EASTERLY WINDS BETWEEN 30W
AND 60W, EXCEPT FOR FRESH WINDS AND SCATTERED MODERATE CONVECTION
NEAR THE TROPICAL WAVE ALONG 54W. A DEEP LAYERED UPPER CYCLONE IS
INTERACTING WITH A SURFACE TROUGH FROM 31N53W TO 24N50W, PRODUCING
SCATTERED MODERATE ISOLATED STRONG CONVECTION FROM 27N TO 31N
BETWEEN 44W AND 53W. FRESH SE WINDS AND SEAS OF 5 TO 6 FT ARE
OCCURRING ACROSS NE PORTIONS OF THIS TROUGH. ENVIRONMENTAL
CONDITIONS NEAR THIS SYSTEM ARE FORECAST TO BECOME MORE CONDUCIVE
FOR DEVELOPMENT BY THE MIDDLE OF THIS WEEK. A TROPICAL DEPRESSION
COULD FORM LATE THIS WEEK AS THE SYSTEM MOVES SLOWLY WEST-
NORTHWESTWARD OVER THE SUBTROPICAL ATLANTIC. THERE IS A MEDIUM
CHANCE OF TROPICAL CYCLONE DEVELOPMENT WITHIN THE NEXT SEVEN DAYS.
TO THE W OF 60W, A 1018 MB HIGH CENTER IS ANALYZED NEAR 28N74W,
AND EXTENDS A WEAK RIDGE TO 60W. THE PRESSURE GRADIENT TO THE S OF
THIS RIDGE IS PROMOTING MODERATE TO FRESH TRADES S OF 23N AND
THROUGH THE BAHAMAS, WITH STRONGEST WINDS OFF HISPANIOLA AND IN
THE WINDWARD PASSAGE. ELSEWHERE W OF 30W, MODERATE OR WEAKER WINDS
AND MODERATE SEAS PREVAIL OVER THE CENTRAL AND EASTERN
SUBTROPICAL WATERS. BROAD LOW PRESSURE ALONG THE NW COAST OF
AFRICA IN RECENT DAYS HAS WEAKENED AND DRIFTED WESTWARD OVER THE
ATLANTIC WATERS BETWEEN NW AFRICA AND 35W, WHERE GENTLE TO
MODERATE NE TO E WINDS GENERALLY PREVAIL N OF 10N, WITH SEAS OF 4
TO 6 FT.
FOR THE FORECAST WEST OF 55W, A BROAD AND WEAK SUBTROPICAL RIDGE
DOMINATES MUCH OF THE BASIN, FORCING FRESH E WINDS OFF HISPANIOLA
AND IN THE WINDWARD PASSAGE. ON TUE, STRONG HIGH PRESSURE BUILDING
SOUTHWARD THROUGH THE EASTERN UNITED STATES WILL BRING A COLD
FRONT INTO THE NW WATERS, INCREASING NE WINDS TO FRESH TO LOCALLY
STRONG BEHIND THE FRONT, AND PRODUCING BUILDING SEAS TO ROUGH N
OF THE BAHAMAS AND W OF 70W THROUGH EARLY THU. CONDITIONS WILL
IMPROVE LATER THU INTO FRI. DURING THE MIDDLE TO LATER PORTION OF
THE WEEK, A TROUGH OF LOW PRESSURE IS FORECAST TO MOVE WEST-
NORTHWESTWARD INTO THE NE PORTION OF THE WATERS, BRINGING
THUNDERSTORMS WHILE ALSO WEAKENING THE HIGH AND PRESSURE GRADIENT.
STRIPLING
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