470
AXNT20 KNHC 171641
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1815 UTC THU SEP 17 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1640 UTC.
..TROPICAL WAVES
THE TROPICAL WAVE OVER THE CENTRAL ATLANTIC HAS BEEN REPOSITIONED
BASED ON SATELLITE IMAGERY AND TROPICAL WAVE DIAGNOSTICS. THE
WAVE AXIS IS NEAR 34W, SOUTH OF 16.5N. SCATTERED MODERATE
CONVECTION IS NOTED FROM 10N TO 17N BETWEEN 30W AND 39W.
A TROPICAL WAVE IN THE E CARIBBEAN HAS BEEN REPOSITIONED BASED ON
SATELLITE IMAGERY AND TROPICAL WAVE DIAGNOSTICS. THE WAVE AXIS IS
NEAR 70W, SOUTH OF 22N. SCATTERED MODERATE CONVECTION IS NOTED
FROM 17N TO 22N BETWEEN 68W AND THE WAVE AXIS.
..MONSOON TROUGH/ITCZ
THE MONSOON TROUGH ENTERS THE ATLANTIC NEAR 18N16W AND EXTENDS
SOUTHWESTWARD TO 09N47W. THE ITCZ EXTENDS FROM 09N47W TO 10N59W.
ASIDE FROM CONVECTION NOTED IN THE TROPICAL WAVES SECTION ABOVE,
SCATTERED MODERATE CONVECTION IS NOTED FROM 06N TO 11N WEST OF
20W. SIMILAR CONVECTION IS DEPICTED FROM 07N TO 11N BETWEEN 45W
AND 49W.
..GULF OF AMERICA
SCATTERED MODERATE CONVECTION IS DEPICTED WEST OF 91W IN
ASSOCIATION TO A SURFACE TROUGH OVER THE AREA. ANOTHER TROUGH
EXTENDS FROM THE WESTERN ATLANTIC TO SOUTH FLORIDA TO 24N86W.
SCATTERED MODERATE CONVECTION IS ALSO PRESENT ALONG THIS TROUGH. THE
PRESSURE GRADIENT BETWEEN A 1027 MB HIGH PRESSURE OVER THE SE OF
THE UNITED STATES AND THE AFOREMENTIONED SURFACE TROUGH OVER THE
SE GULF SUPPORTS FRESH NE TO E WINDS AND MODERATE SEAS OVER THE NE
AND NORTH- CENTRAL GULF. ELSEWHERE, MODERATE OR WEAKER WINDS,
AND SLIGHT SEAS, ARE NOTED.
FOR THE FORECAST, THE AFOREMENTIONED PRESSURE GRADIENT WILL
SPREAD WESTWARD OVER THE REMAINDER OF THE NORTHERN GULF WATERS
THROUGH TONIGHT BEFORE IMPROVING FRI INTO SAT. MEANWHILE, A RATHER
BROAD UPPER- LEVEL LOW WILL MOVE TOWARDS FLORIDA FROM THE WESTERN
ATLANTIC TODAY THROUGH FRI. THIS FEATURE WILL LEAD TO INCREASING
SHOWER AND THUNDERSTORM ACTIVITY OVER THE EASTERN AND CENTRAL GULF
WATERS.
..CARIBBEAN SEA
AN UPPER LEVEL TROUGH IS SUPPORTING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS OVER THE NW CARIBBEAN. WHILE, A MID-LEVEL
TROUGH IS SUPPORTING NUMEROUS SHOWERS WEST OF 81.5W. PLEASE READ
THE TROPICAL WAVE SECTION ABOVE FOR ADDITIONAL CONVECTION ACROSS
THE BASIN. THE PRESSURE GRADIENT BETWEEN RIDGING NORTH OF THE AREA
ALONG WITH LOWER PRESSURE OVER COLOMBIA- VENEZUELA IS SUPPORTING
FRESH TO STRONG TRADES OVER THE S CENTRAL CARIBBEAN. SEAS 6 TO 8
FT ARE OVER THESE WATERS. MODERATE TO FRESH WINDS, AND MODERATE
SEAS, ARE ELSEWHERE EAST OF 84W. WEST OF 84W, GENTLE TO MODERATE
WINDS AND SEAS 2 TO 4 FT PREVAIL.
FOR THE FORECAST, THE AFOREMENTIONED PRESSURE GRADIENT WILL
GENERALLY MAINTAIN FRESH TO STRONG TRADES ALONG WITH MODERATE TO
LOCALLY ROUGH SEAS OVER MOST OF THE CENTRAL CARIBBEAN THROUGH THE
END OF THE WEEK. OTHERWISE, MODERATE TO FRESH TRADES AND MODERATE
SEAS WILL CONTINUE ACROSS THE EASTERN CARIBBEAN THROUGH THE
WEEKEND WHILE LIGHT TO GENTLE WINDS AND SLIGHT TO MODERATE SEAS
WILL DOMINATE THE NW PART OF THE BASIN. A TROPICAL WAVE IS
ENTERING THE CENTRAL CARIBBEAN, AND WILL REACH THE WESTERN
CARIBBEAN OVER THE WEEKEND. SCATTERED SHOWERS AND THUNDERSTORMS
WILL ACCOMPANY THE PASSAGE OF THE WAVE.
..ATLANTIC OCEAN
A STATIONARY FRONT EXTENDS FROM NEAR BERMUDA WEST-SOUTHWESTWARD TO
OCEAN REEF, FLORIDA. MODERATE TO FRESH NE WINDS AND SEAS 5 TO 6 FT
PREVAIL N OF THE FRONT. SCATTERED MODERATE CONVECTION IS NOTED
NORTH OF 23N AND WEST OF 66W IN ASSOCIATION TO THIS FRONTAL
BOUNDARY. LIGHT TO GENTLE WINDS, AND SLIGHT SEAS, ARE SE OF THE
FRONT N OF 23N AND W OF 55W. AN UPPER LEVEL TROUGH THAT EXTENDS
FROM NORTH OF PUERTO RICO AND THE U.S. VIRGIN ISLANDS TO AROUND
31N IS SUPPORTING SCATTERED MODERATE CONVECTION SOUTH OF 24N
BETWEEN 56W AND 70W AND NORTH OF 26N BETWEEN 40W AND 59W.
ADDITIONAL CONVECTION IN THE BASIN IS DESCRIBED IN THE TROPICAL
WAVES AND MONSOON TROUGH/ITCZ SECTIONS ABOVE. FRESH TO LOCALLY
STRONG NE WINDS, AND MODERATE SEAS, ARE NOTED NEAR THE CANARY
ISLANDS, EXTENDING SW TO NEAR 30W. ELSEWHERE, GENTLE TO MODERATE
WINDS AND MODERATE SEAS PREVAIL.
FOR THE FORECAST WEST OF 55W, THE PRESSURE GRADIENT BETWEEN HIGH
PRESSURE OVER THE SOUTHEASTERN U.S. AND A STATIONARY FRONT THAT
EXTENDS FROM NEAR BERMUDA TO THE NW BAHAMAS WILL MAINTAIN MODERATE
TO FRESH NE WINDS AND MODERATE SEAS WEST OF THE FRONT THROUGH
TODAY. CONDITIONS WILL IMPROVE LATE TODAY INTO FRI AS HIGH
PRESSURE BECOMES THE DOMINANT FEATURE ACROSS THE BASIN INTO THE
WEEKEND. MEANWHILE, A BROAD UPPER-LEVEL LOW LOCATED EAST OF
FLORIDA IN COMBINATION WITH A VERY MOIST AND UNSTABLE ENVIRONMENT
WILL CONTINUE TO SUPPORT SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS OVER MOST OF THE FORECAST WATERS THE NEXT FEW DAYS
AS IT MOVES TOWARD FLORIDA ON FRI.
KRV
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