071
AXNT20 KNHC 022318
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0015 UTC SAT OCT 3 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
2300 UTC.
..TROPICAL WAVES
A TROPICAL WAVE IS ALONG 39W FROM 06N TO 20N, MOVING WESTWARD AT
15 TO 20 KT. SCATTERED SHOWERS ARE NEAR THE WAVE AXIS.
A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN WITH AXIS ALONG
73W, MOVING WESTWARD AT 15 KT. THE WAVE EXTENDS FROM HAITI TO
NORTHERN COLOMBIA WHERE IS HELPING TO INDUCE SOME CONVECTIVE
ACTIVITY.
..MONSOON TROUGH/ITCZ
THE MONSOON TROUGH ENTERS THE ATLANTIC NEAR 12N16W AND CONTINUES
SOUTHWESTWARD TO 08N22W AND THEN WEST-NORTHWESTWARD TO 12N35W.
THE ITCZ EXTENDS FROM 07N40W TO NEAR TRINIDAD AND TOBAGO. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS EVIDENT FROM 05N TO 12N
BETWEEN 43W AND 52W. SIMILAR CONVECTIVE ACTIVITY IS AFFECTING
TRINIDAD AND TOBAGO AND REGIONAL WATERS.
..GULF OF AMERICA
AN UPPER-LEVEL LOW SPINNING JUST WEST OF THE NORTHERN YUCATAN
PENINSULA SUPPORTS SCATTERED SHOWERS AND THUNDERSTORMS OVER PARTS
OF THE GULF REGION. CONVECTION IS CURRENTLY FLARED-UP OVER THE
YUCATAN PENINSULA, AND ALSO ALONG THE COAST OF MEXICO SOUTH OF
TAMPICO. A SURFACE TROUGH IS ANALYZED OVER THE CENTRAL GULF AND
RUNS FROM THE WESTERN FLORIDA PANHANDLE TO THE CENTRAL BAY OF
CAMPECHE. THE PRESSURE GRADIENT BETWEEN THIS TROUGH AND HIGH
PRESSURE LOCATED OVER THE WESTERN ATLANTIC IS ALLOWING FOR MOSTLY
FRESH EAST TO SOUTHEAST WINDS TO EXIST ACROSS THE CENTRAL AND
EASTERN GULF WATERS. LIGHT TO GENTLE WINDS ARE OCCURRING WEST OF
THE TROUGH AXIS. SEAS ARE GENERALLY MODERATE, EXCEPT IN THE BAY
OF CAMPECHE WHERE SEAS IN THE 1 TO 3 FT RANGE ARE NOTED.
FOR THE FORECAST, THE UPPER-LEVEL LOW WILL CONTINUE TO SUSTAIN
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS OVER MOST OF THE
EASTERN AND CENTRAL GULF THROUGH THE WEEKEND. A WEAK COLD FRONT
IS EXPECTED TO MOVE ACROSS THE NW GULF THIS WEEKEND, AND STALL
FROM THE FLORIDA PANHANDLE TO NW GULF AND TO THE SW BY LATE SUN.
WEAK LOW PRESSURE MAY RIDE UP ALONG THE FRONT DURING THE WEEKEND
AND INTO MON ENHANCING WINDS SOME IN THE NW AND NORTH-CENTRAL
GULF. MODERATE NE WINDS ARE EXPECTED ELSEWHERE BEHIND THE FRONT.
THE FRONT WILL REMAIN STATIONARY INTO MIDWEEK. FRESH TO STRONG
NORTHEAST WINDS ARE EXPECTED BEHIND THE FRONT BEGINNING TUE,
MAINLY IN THE NE AND NORTH-CENTRAL GULF, AS STRONG HIGH PRESSURE
BUILDS SOUTHWARD BEHIND IT.
..CARIBBEAN SEA
AN UPPER-LEVEL LOW CURRENTLY WEST OF THE NORTHERN YUCATAN PENINSULA
IS PULLING UP ABUNDANT DEEP TROPICAL MOISTURE ACROSS THE FAR WESTERN
CARIBBEAN AND NORTHERN CENTRAL AMERICA WHERE SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS ARE PRESENT. HIGH PRESSURE NORTH OF THE
AREA, COMBINED WITH THE COLOMBIAN LOW IS SUPPORTING MODERATE TO
FRESH EASTERLY TRADE WINDS ACROSS MUCH OF THE CARIBBEAN SEA WITH
MODERATE SEAS. SHOWERS AND THUNDERSTORMS ARE SEEN OVER PARTS OF
THE GREATER ANTILLES. A DIFFLUENT PATTERN ALOFT IS HELPING TO
INDUCE THIS CONVECTIVE ACTIVITY.
FOR THE FORECAST, THE UPPER-LEVEL LOW WILL MAINTAIN SCATTERED SHOWER
AND THUNDERSTORM ACTIVITY QUITE ACTIVE OVER THAT PORTION OF THE BASIN
INTO SAT MORNING AS THE LOW MOVES WESTWARD. A MODERATE PRESSURE GRADIENT
BETWEEN THE BERMUDA HIGH NORTH OF THE CARIBBEAN, AND RELATIVELY LOWER
PRESSURE IN NORTHERN SOUTH AMERICA WILL BRING FRESH TO LOCALLY STRONG
TRADES OVER THE SOUTH-CENTRAL CARIBBEAN AND IN THE GULF OF HONDURAS
THROUGH SAT NIGHT. AS A FRONTAL BOUNDARY REACHES THE WATERS NORTH
OF THE BAHAMAS, THE PRESSURE GRADIENT WILL SLACKEN AGAIN FROM SUN
THROUGH EARLY NEXT WEEK LEADING TO GENTLE TO MODERATE TRADES ACROSS
THE BASIN. TRADES MAY PULSE TO FRESH TO STRONG SPEEDS OFF COLOMBIA
AND IN THE GULF OF VENEZUELA MON NIGHT.
OF NOTE, LOCALLY HEAVY RAIN AND A FEW STRONG THUNDERSTORMS ARE POSSIBLE
ACROSS HISPANIOLA THIS WEEKEND, PARTICULARLY OVER HAITI AND
WESTERN HISPANIOLA. A MID-UPPER LEVEL TROUGH WILL DEEPEN TOWARD
HISPANIOLA AND DEVELOP A CLOSED CIRCULATION NEAR THE ISLAND BY
SUN. THIS COMBINED WITH AVAILABLE MOISTURE AND LOCAL EFFECTS AS
DAYTIME HEATING, LOCAL SEA BREEZES AND MOUNTAIN UPSLOPE LIFTING
WILL LIKELY INCREASE THE CHANCES OF RAIN IN THE AREA.
..ATLANTIC OCEAN
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A TROUGH (THE REMNANTS
OF FORMER TROPICAL STORM FAY) LOCATED SEVERAL HUNDRED MILES SOUTHEAST
OF BERMUDA HAVE BECOME LESS ORGANIZED DURING THE PAST SEVERAL
HOURS. THE TROUGH EXTENDS FROM 29N55W TO 20N63W. SCATTEROMETER
DATA INDICATE THE WIND SHIFT ASSOCIATED WITH TROUGH AXIS, WITH
MODERATE TO FRESH NE TO E WINDS N OF 25N AND W OF THE TROUGH AXIS
TO 60W. DRY AIR AND STRONG UPPER-LEVEL WINDS ARE EXPECTED TO PREVENT
SIGNIFICANT RE-DEVELOPMENT. WINDS AND SEAS COULD BE HIGHER NEAR
THUNDERSTORMS.
THE REMAINDER OF THE FORECAST AREA IS UNDER THE INFLUENCE OF A
RIDGE, WITH THE MAIN HIGH PRESSURE CENTER OF 1025 MB LOCATED NE
OF THE AZORES. A 1021 MB HIGH PRESSURE IS ANALYZED OVER THE
WESTERN ATLANTIC NEAR 33N69W. MODERATE TO LOCALLY FRESH E WINDS
ARE OBSERVED JUST OFFSHORE HISPANIOLA, AND BETWEEN EASTERN CUBA
AND THE BAHAMAS WITH SEAS OF 3 TO 5 FT. ELSEWHERE MODERATE OR
WEAKER WINDS PREVAIL WITH MODERATE SEAS.
FOR THE FORECAST WEST OF 55W, SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WILL REMAIN POSSIBLE ACROSS THE WATERS WEST OF 75W
THROUGH AT LEAST SAT. MEANWHILE, THE COMBINATION OF THE ABOVE
MENTIONED TROUGH AND A BROAD UPPER-LEVEL TROUGH DIGGING SOUTHWARD
WILL CONTINUE TO SUPPORT SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH THE WEEKEND NORTH OF ABOUT 22N AND EAST OF 70W. TRADES
JUST NORTH OF HISPANIOLA WILL PULSE TO FRESH TO LOCALLY STRONG
SPEEDS TONIGHT AND ON SAT NIGHT. OTHERWISE, RATHER TRANQUIL
CONDITIONS ARE EXPECTED THROUGH WED. LOOKING AHEAD, A COLD FRONT
MAY REACH THE WATERS OFF OF NE FLORIDA TUE MORNING AND STALL.
STRONG HIGH PRESSURE WILL NUDGE SOUTHWARD BEHIND THE FRONT WITH
THE RESULTANT PRESSURE GRADIENT BETWEEN IT AND THE FRONT LIKELY
TO INDUCE STRONG NORTHEAST WINDS, WITH POTENTIAL TO NEAR GALE
FORCE, AND ALONG WITH BUILDING SEAS OFFSHORE NE FLORIDA.
GR
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