201
AXNT20 KNHC 180435
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0615 UTC FRI SEP 18 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
A CENTRAL ATLANTIC TROPICAL WAVE HAS ITS AXIS ALONG 36W FROM 03N
TO 18N, MOVING WESTWARD NEAR 15 KT. SCATTERED MODERATE CONVECTION
IS FROM 08N TO 15N BETWEEN 31W AND 42W.
A CENTRAL CARIBBEAN TROPICAL WAVE HAS ITS AXIS ALONG 72W, MOVING
WESTWARD AT 10 TO 15 KT. SCATTERED MODERATE CONVECTION IS NOTED
ALONG THE WAVE AXIS AND N OF 17N.
..MONSOON TROUGH/ITCZ
THE MONSOON TROUGH ENTERS THE ATLANTIC NEAR 18N16W AND CONTINUES
SOUTHWESTWARD TO 10N39W, WHERE IT TRANSITIONS TO THE ITCZ TO
07N58W. ASIDE FROM CONVECTION ASSOCIATED TO THE TROPICAL WAVES AS
DESCRIBED ABOVE, SCATTERED MODERATE CONVECTION IS EVIDENT FROM
09N TO 12N BETWEEN 47W AND 51W.
..GULF OF AMERICA
A TROUGH IS ANALYZED FROM JUST WEST OF THE BAHAMAS, SOUTHWESTWARD
ACROSS EXTREME SOUTH FLORIDA AND TO JUST NORTH OF THE FLORIDA
KEYS, REACHING TO NEAR 24N86W. A WESTERN GULF TROUGH EXTENDS FROM
25N96W TO 24N97W AND TO 19N94W. SCATTERED MODERATE CONVECTION IS
NOTED ALONG BOTH TROUGHS. THE PRESSURE GRADIENT BETWEEN HIGH
PRESSURE OVER THE SOUTHEASTERN U.S. AND A WEAKENING FRONTAL 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, FRESH NE TO E WINDS AND MODERATE SEAS
OVER THE NE AND NORTH-CENTRAL GULF 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 ON FRI, AND
INTO THE NE GULF ON SAT. THIS FEATURE WILL LEAD TO INCREASING
SHOWER AND THUNDERSTORM ACTIVITY OVER FLORIDA, AND THEN OVER THE
EASTERN AND CENTRAL GULF WATERS. FAIRLY TRANQUIL MARINE CONDITIONS
ARE FORECAST BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK.
..CARIBBEAN SEA
THE PRESSURE GRADIENT BETWEEN WEAKENING HIGH PRESSURE OVER THE
WESTERN ATLANTIC AND RELATIVELY LOWER PRESSURE IN NORTHERN SOUTH
AMERICA IS ALLOWING FOR FRESH TO STRONG TRADES OVER THE SOUTH-
CENTRAL CARIBBEAN. SEAS IN THE RANGE OF 6 TO 8 FT ARE OVER THESE
WATERS. MODERATE TO FRESH TRADES ALONG WITH MODERATE SEAS ARE
ELSEWHERE E OF 82W WHILE GENTLE TO MODERATE TRADES AND SEAS OF 2
TO 4 FT ARE W OF 82W, EXCEPT FOR HIGHER SEAS OF 4 TO 5 FT SOUTH
OF 17N AS NOTED IN A SATELLITE SCATTEROMETER DATA PASS.
UPPER-LEVEL DIVERGENCE EAST OF AN UPPER-LEVEL LOW THAT IS OVER
THE NORTHERN YUCATAN PENINSULA IS SUPPORTING SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS OVER THE NORTHWESTERN CARIBBEAN. AN
UPPER-LEVEL DISTURBANCE RIDING ALONG A JET STREAM BRANCH IS
KEEPING ACTIVE WEATHER IN THE FORM OF NUMEROUS MODERATE CONVECTION
OVER THE WATERS FROM 11N TO 17N WEST OF 80W TO INLAND (NEAR 85W)
OF HONDURAS AND NICARAGUA. SCATTERED MODERATE CONVECTION IS OVER
THE INTERIOR OF HONDURAS.
FOR THE FORECAST, THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE
OVER THE WESTERN ATLANTIC AND THE COLOMBIAN LOW WILL GENERALLY
MAINTAIN FRESH TO STRONG TRADES ALONG WITH MODERATE TO LOCALLY
ROUGH SEAS OVER MOST OF THE CENTRAL CARIBBEAN THROUGH FRI NIGHT.
WINDS WILL DIMINISH TO MODERATE TO FRESH SPEEDS OVER THE UPCOMING
WEEKEND INTO EARLY NEXT WEEK AS THE PRESSURE GRADIENT RELAXES
ACROSS THE AREA. MODERATE OR WEAKER WINDS AND SLIGHT TO MODERATE
SEAS ARE FORECAST ELSEWHERE.
..ATLANTIC OCEAN
A STATIONARY FRONT EXTENDS FROM NEAR 31N68W SOUTHWESTWARD TO
27N75W AND TO EXTREME SOUTH FLORIDA. MODERATE TO FRESH NORTHEAST
WINDS AND SEAS 5 TO 6 FT ARE NORTH OF OF THE FRONT. SCATTERED
MODERATE CONVECTION IS SEEN NORTH OF ABOUT 23N AND WEST OF 66W
IN ASSOCIATION TO THIS FRONTAL BOUNDARY. LIGHT TO GENTLE WINDS
AND SLIGHT SEAS ARE SOUTHEAST OF THE FRONT NORTH OF 23N AND WEST
OF 55W. A SURFACE TROUGH IS ANALYZED ALONG 48W AND N OF 23N.
SCATTERED MODERATE CONVECTION IS NOTED ALONG THE TROUGH AND IN ITS
VICINITY MAINLY N OF 26N BETWEEN 43W-51W. 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 NORTH
OF 24N AND W OF 60W. TO THE EAST, FRESH TO STRONG NORTH TO
NORTHEAST WINDS AND MODERATE SEAS PER LATEST SCATTEROMETER DATA
PASSES ARE NEAR THE CANARY ISLANDS. THEY EXTEND WESTWARD TO NEAR
30W. ELSEWHERE, GENTLE TO MODERATE WINDS AND MODERATE SEAS
PREVAIL.
FOR THE FORECAST WEST OF 55W, THE PRESSURE GRADIENT OVER THE W
ATLANTIC WILL MAINTAIN MODERATE TO FRESH NE WINDS AND MODERATE
SEAS WEST OF THE FRONT THROUGH TONIGHT. CONDITIONS WILL IMPROVE
EARLY ON FRI AS HIGH PRESSURE BECOMES THE DOMINANT FEATURE ACROSS
THE BASIN INTO THE WEEKEND INTO EARLY NEXT WEEK. MEANWHILE,
ABUNDANT TROPICAL MOISTURE, COMBINED WITH AN UPPER-LEVEL LOW
LOCATED EAST OF FLORIDA, WILL CONTINUE TO SUPPORT SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS, MAINLY W OF 70W, THROUGH AT
LEAST SUN.
ERA
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