421
AXNT20 KNHC 190001
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0015 UTC SAT SEP 19 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.
..TROPICAL WAVES
A CENTRAL ATLANTIC TROPICAL WAVE HAS ITS AXIS EXTENDING FROM NEAR
21N44W TO 11N42W. IT IS MOVING WESTWARD 10 TO 15 KT. SCATTERED
MODERATE ISOLATED STRONG CONVECTION IS EAST OF THE WAVE FROM 15N
TO 18N BETWEEN 39W AND 42W. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE FROM 12N TO 16N BETWEEN 33W AND 39W.
A WESTERN CARIBBEAN TROPICAL WAVE HAS ITS AXIS ROUGHLY ALONG 80W
SOUTH OF 19N TO CENTRAL PANAMA AND MOVING WESTWARD NEAR 15 KT.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS SOUTHWEST OF
JAMAICA, WHILE NUMEROUS MODERATE TO STRONG CONVECTION IS ALONG
THE INTERSECTION OF THE WAVE AND THE EASTERN PACIFIC MONSOON
TROUGH, ACROSS THE COASTAL WATERS OF PANAMA AND COLOMBIA.
..MONSOON TROUGH/ITCZ
THE MONSOON TROUGH AXIS ENTERS THE ATLANTIC ALONG THE COAST OF
SENEGAL NEAR 14N17W AND CONTINUES SOUTHWESTWARD TO 11N21W TO
12.5N31W TO 13N38W AND NORTHWESTWARD TO 16N48W. THE ITCZ EXTENDS
FROM 12N48W TO 13N52W TO 11N57W TO 10N62W. ASIDE FROM CONVECTION
ASSOCIATED TO THE TROPICAL WAVE DESCRIBED ABOVE, SCATTERED
MODERATE ISOLATED STRONG CONVECTION IS WITHIN 60 NM NORTH OF THE
ITCZ BETWEEN 48W-51W. SCATTERED MODERATE CONVECTION IS FROM 06N
TO 10N BETWEEN 22W-31W.
..GULF OF AMERICA
LOW-LEVEL RESIDUAL MOISTURE FROM A RECENT FRONTAL BOUNDARY
REMAINS OVER THE SOUTHERN GULF SOUTH OF ABOUT 26N BETWEEN
FLORIDA AND MEXICO. SCATTERED MODERATE CONVECTION IS PRESENT
FROM 22N TO 26N BETWEEN 82W AND 94W. ISOLATED SHOWERS AND
THUNDERSTORMS ARE OVER SOME SECTIONS OF THE STRAITS OF FLORIDA.
AT THE SURFACE, A BROAD HIGH PRESSURE RIDGE EXTENDS ACROSS THE
SOUTHEASTERN U.S. ALONG ABOUT 34N, AND IS PROMOTING GENTLE TO
MODERATE EASTERLY WINDS ACROSS THE BASIN NORTH OF 25N, WHERE
SEAS ARE 4 TO 7 FT. A TROUGH IS ANALYZED FROM NEAR 26N90W TO
23N92W AND TO 21.5N95W. THIS FEATURE IS AIDING IN FOCUSING
CONVECTION TO ITS EAST, AND PROMOTING THE STRONGEST WINDS AND
SEAS ACROSS THE BASIN ACROSS THE NORTHERN END OF THE TROUGH.
LIGHT TO GENTLE MOSTLY EASTERLY WINDS PREVAIL SOUTH OF 25N PER
LATEST SATELLITE SCATTEROMETER DATA AND BUOY OBSERVATIONS. SEAS
OVER THIS PART OF THE GULF ARE 2 TO 4 FT. SCATTERED SHOWERS AND
THUNDERSTORMS ARE OVER MOST OF THE YUCATAN PENINSULA. ISOLATED
SHOWERS AND THUNDERSTORMS ARE ELSEWHERE OVER THE BASIN SOUTH OF
27N.
FOR THE FORECAST, THE AFOREMENTIONED RIDGE WILL DOMINATE THE
GULF REGION SUPPORTING GENTLE TO MODERATE WINDS AND SLIGHT TO
MODERATE SEAS THROUGH SUN. WINDS WILL THEN EASE TO LIGHT TO
GENTLE SPEEDS EARLY NEXT WEEK, WITH SEAS REMAINING SLIGHT.
MEANWHILE, A BROAD UPPER-LEVEL LOW CURRENTLY LOCATED OVER
NORTHEASTERN FLORIDA WILL MOVE INTO THE NE GULF ON SAT. THIS
FEATURE WILL LEAD TO INCREASING SHOWER AND THUNDERSTORM ACTIVITY
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
PLEASE REFER TO THE TROPICAL WAVE SECTION FOR DETAILS ON A WAVE IN
THE CENTRAL CARIBBEAN INCLUDING ASSOCIATED CONVECTION. UPPER-
LEVEL DISTURBANCES RIDING ALONG A JET STREAM BRANCH ACROSS THE
NORTHWEST CARIBBEAN ARE SUPPORTING SCATTERED MODERATE CONVECTION
ACROSS THE GULF OF HONDURAS AND NEAR THE TROPICAL WAVE. ELSEWHERE,
FAIR SKIES PREVAIL ACROSS THE BASIN.
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 CENTRAL
CARIBBEAN SOUTH OF 17N BETWEEN 66W AND 78W, WHERE SEAS ARE 6 TO 9
FT. MODERATE TO FRESH TRADES ARE FOUND ELSEWHERE FROM 10N TO 19N
TO THE EAST OF 80W, ALONG WITH SEAS OF 4 TO 7 FT. GENTLE TO
MODERATE WINDS, AND SEAS OF 3 TO 5 FT REMAIN ACROSS THE
REMAINDER OF THE BASIN, EXCEPT FOR SEAS TO 6 FT ACROSS SOUTHWEST
PORTIONS ACROSS THE WESTERN COASTAL WATERS OF PANAMA.
FOR THE FORECAST, THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER
HE WESTERN ATLANTIC AND RELATIVELY LOWER PRESSURE IN NORTHERN
SOUTH AMERICA WILL GENERALLY MAINTAIN FRESH TO STRONG TRADES
ALONG WITH MODERATE TO LOCALLY ROUGH SEAS OVER MOST OF THE
CENTRAL CARIBBEAN THROUGH EARLY SAT MORNING. WINDS WILL DIMINISH
TO MODERATE TO FRESH SPEEDS THEREAFTER AS THE PRESSURE GRADIENT
RELAXES ACROSS THE AREA. MODERATE OR WEAKER WINDS AND SLIGHT TO
MODERATE SEAS ARE FORECAST ELSEWHERE.
..ATLANTIC OCEAN
A WEAKENING STATIONARY FRONT EXTENDS FROM NEAR 31N72W TO NEAR
29N79W. BROAD UPPER LEVEL LOW PRESSURE OVER NORTHERN FLORIDA IS
PROMOTING UNSTABLE CONDITIONS ACROSS MUCH OF THE AREA W OF 68W.
CONVERGING LOW-LEVEL MOISTURE ASSOCIATED WITH THE FRONT IS
PRODUCING SCATTERED MODERATE ISOLATED STRONG CONVECTION FROM 22N
TO 28N BETWEEN THE STRAITS OF FLORIDA AND 68W. SIMILAR ACTIVITY
IS SOUTH OF 22N BETWEEN 69W AND 76W, REACHING THE INTERIOR
PORTIONS OF HISPANIOLA AND EASTERN CUBA. RECENT SATELLITE
SCATTEROMETER DATA SHOWS GENTLE TO MODERATE NORTHEAST WINDS
NORTH OF HE FRONT, WHERE SEAS ARE 4 TO 6 FT. WINDS ARE LIGHT
TO GENTLE BETWEEN 60W AND SOUTH FLORIDA SOUTH OF THE FRONT,
EXCEPT FOR FRESH SOUTHEAST WINDS ALONG THE NORTHERN COAST
OF HISPANIOLA TO 22N. WEAK HIGH PRESSURE AND LIGHT WINDS PREVAIL
EAST OF THE FRONT TO NEAR 46W. A TROUGH EXTENDS FROM NEAR
31N44W TO 27N48W AND TO 25N55W. SCATTERED MODERATE CONVECTION
IS WITHIN 180 NM SOUTHEAST OF THE TROUGH BETWEEN 49W AND 55W.
SCATTERED SHOWERS AND THUNDERSTORMS ARE SEEN FROM 25N TO 31N
BETWEEN 40W AND 55W. TO THE NORTHEAST, A 1023 MB HIGH CENTER
IS NEAR 35N44W. ASSOCIATED BROAD RIDGING COVERS THE EASTERN AND
CENTRAL ATLANTIC. MOSTLY MODERATE NORTHEAST TO EAST TRADES
PREVAIL SOUTH OF 25N BETWEEN THE CABO VERDES AND THE TROPICAL
WAVE THAT IS ALONG THE POSITION OF 21N44W TO 11N42W, WHERE SEAS
ARE 5 TO 7 FT. WELL TO THE EAST, FRESH TO STRONG NORTH TO
NORTHEAST WINDS AND 6 TO 8 FT SEAS ARE FOUND FROM 16N TO 22N
BETWEEN AFRICA AND 20W DUE TO A TIGHT PRESSURE GRADIENT BETWEEN
LOW PRESSURE IN NW AFRICA AND THE ATLANTIC RIDGE. MODERATE TO
FRESH NORTH TO NORTHEAST WINDS AND SEAS OF 6 TO 8 FT ARE
ELSEWHERE FROM 16N TO 31N TO THE EAST OF 28W. MODERATE OR WEAKER
WINDS AND MODERATE SEAS DOMINATE THE REMAINDER OF THE TROPICAL
ATLANTIC WATERS.
FOR THE FORECAST WEST OF 55W, THE WEAKENING STATIONARY FRONT
WILL DISSIPATE LATE TONIGHT, OR EARLY ON SAT. HIGH PRESSURE WILL
BECOME THE DOMINANT FEATURE ACROSS THE BASIN DURING THE WEEKEND
INTO EARLY NEXT WEEK, PROMOTING LIGHT TO GENTLE WINDS WITH SLIGHT
TO MODERATE SEAS, WITH THE EXCEPTION OF MODERATE TO LOCALLY
FRESH E TO SE WINDS AND MODERATE SEAS OFFSHORE HISPANIOLA.
MEANWHILE, ABUNDANT TROPICAL MOISTURE, COMBINED WITH AN UPPER-
LEVEL LOW THAT IS PRESENTLY OVER NORTHEAST FLORIDA, WILL
CONTINUE TO SUPPORT SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS, MAINLY WEST OF ABOUT 70W THROUGH AT LEAST SUN.
AGUIRRE
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