991
AXNT20 KNHC 172358
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0015 UTC THU JUN 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2000 UTC.
..SPECIAL FEATURES
TROPICAL STORM ARTHUR IS CENTERED NEAR 29.4N 94.9W AT 17/0000 UTC OR
10 NM NW OF GALVESTON TEXAS, MOVING NE AT 7 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT
WITH GUSTS TO 45 KT. NUMEROUS MODERATE TO SCATTERED STRONG
THUNDERSTORMS ARE ACTIVE FROM ROUGHLY N OF 23N BETWEEN 88W AND 96W.
PEAK SEAS ARE CURRENTLY AROUND 11 FT. ARTHUR IS MOVING ERRATICALLY
TOWARD THE NORTHEAST. A NORTHEASTWARD TO NORTH-NORTHEASTWARD MOTION
SHOULD CONTINUE THROUGH TONIGHT. ON THE FORECAST TRACK, THE CENTER
OF ARTHUR SHOULD MOVE FARTHER INLAND OVER SOUTHEASTERN TEXAS TONIGHT.
WEAKENING IS EXPECTED AS THE CENTER OF ARTHUR MOVES FARTHER INLAND,
AND IT COULD DISSIPATE LATER TONIGHT OR EARLY THU. POTENTIALLY LIFE-
THREATENING FLASH FLOODING AND URBAN FLOODING ARE LIKELY THROUGH
FRIDAY ACROSS SOUTHERN LOUISIANA, SOUTHERN MISSISSIPPI, SOUTHERN
ALABAMA, SOUTHWESTERN GEORGIA, AND THE FLORIDA PANHANDLE. SCATTERED
MINOR RIVER FLOODING IS EXPECTED, WITH THE POTENTIAL FOR ISOLATED
MODERATE TO MAJOR RIVER FLOODING. ONGOING HEAVY RAINFALL COULD
PROLONG THE FLOOD THREAT THROUGH THE WEEKEND. PLEASE READ THE LATEST
HIGH SEAS FORECAST ISSUED BY THE NATIONAL HURRICANE CENTER AT WEBSITE
- HTTPS://WWW.NHC.NOAA.GOV/TEXT/MIAHSFAT2.SHTML AND THE LATEST
ARTHUR NHC FORECAST/ADVISORY AND PUBLIC ADVISORY AT
WWW.HURRICANES.GOV FOR MORE DETAILS.
..TROPICAL WAVES
A TROPICAL WAVE IS OFFSHORE WESTERN AFRICA, ALONG 19.5W, SOUTH OF
17N, MOVING WESTWARD AROUND 20 KT. ANY NEARBY CONVECTION IS
DESCRIBED BELOW WITH THE MONSOON TROUGH/ITCZ SECTION.
AN EASTERN ATLANTIC TROPICAL WAVE IS ALONG 36W, SOUTH OF 16N,
MOVING WESTWARD AT AROUND 10 KT. ANY NEARBY CONVECTION IS
DESCRIBED BELOW WITH THE MONSOON TROUGH/ITCZ SECTION.
AN ATLANTIC TROPICAL WAVE IS ALONG 60W, SOUTH OF 18N TO NEAR
TRINIDAD AND TOBAGO AND THE BORDER OF GUYANA AND VENEZUELA,
MOVING WESTWARD AT AROUND 20 KT. ANY NEARBY CONVECTION IS
DESCRIBED BELOW WITH THE MONSOON TROUGH/ITCZ SECTION.
A CENTRAL CARIBBEAN TROPICAL WAVE IS ALONG 78W, SOUTH OF 18N NEAR
SE JAMAICA TO ACROSS EXTREME WESTERN COLOMBIA, MOVING WESTWARD AT
AROUND 20 KT. ANY NEARBY CONVECTION IS DESCRIBED BELOW WITH THE
MONSOON TROUGH/ITCZ SECTION.
..MONSOON TROUGH/ITCZ
THE MONSOON TROUGH EXTENDS FROM THE COAST OF AFRICA NEAR 13.5N17W
SOUTHWESTWARD TO 10N17.5W. THE ITCZ EXTENDS FROM 06.5N20.5W TO
05N26W TO 07N35W, THEN RESUMES WEST OF A TROPICAL WAVE FROM 06N38W
TO NEAR THE COAST OF BRAZIL AT 00N51W. SCATTERED MODERATE ISOLATED
STRONG CONVECTION IS NOTED FROM 02N TO 08N TO THE EAST OF 44W TO
NEAR AFRICA, SOMEWHAT ENHANCED BY TROPICAL WAVES DESCRIBED ABOVE.
..GULF OF AMERICA
PLEASE REFER TO THE SPECIAL FEATURES SECTION ABOVE FOR DETAILS ON
NEWLY FORMED TROPICAL STORM ARTHUR IMPACTING PORTIONS OF THE NW
GULF AND ADJACENT LAND AREAS.
OUTSIDE OF THE CONDITIONS CONCERNING TROPICAL STORM ARTHUR
DISCUSSED ABOVE IN THE THE SPECIAL FEATURES SECTION, THE REMAINDER
OF THE GULF IS UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE THAT
EXTENDS FROM THE WESTERN ATLANTIC, ACROSS FLORIDA INTO THE CENTRAL
GULF. THIS PATTERN IS SUPPORTING MODERATE TO FRESH SE TO S WINDS
ACROSS MOST OF THE BASIN. SEAS ARE 2-4 FT TO THE EAST OF 86W AND
ALSO SOUTH OF 22N, WITH 4-7 FT SEAS ELSEWHERE AROUND ARTHUR.
FOR THE FORECAST, ARTHUR WILL WEAKEN TO A REMNANT LOW NEAR 30.8N
94.6W THU MORNING, AND DISSIPATE THU AFTERNOON. SWELLS GENERATED BY
ARTHUR ARE LIKELY TO CAUSE LIFE-THREATENING SURF AND RIP CURRENT
CONDITIONS ALONG THE NORTHWESTERN GULF COAST FOR THE NEXT DAY OR
TWO. OTHERWISE, A TIGHTENING PRESSURE GRADIENT WILL DEVELOP OVER THE
BASIN AND SUSTAIN FRESH TO STRONG SOUTHERLY WINDS OVER THE WESTERN
AND CENTRAL GULF TONIGHT THROUGH THU NIGHT, AND MODERATE TO FRESH
WINDS OVER THE EASTERN GULF. WINDS AND SEAS WILL BEGIN TO DIMINISH
LATE FRI THROUGH THE WEEKEND AS WEAK HIGH PRESSURE SETTLES OVER THE
EASTERN GULF.
..CARIBBEAN SEA
THE BROAD SUBTROPICAL RIDGE OVER THE WESTERN ATLANTIC IS
MAINTAINING FRESH TO STRONG EASTERLY TRADE WINDS AND MODERATE TO
ROUGH SEAS IN THE CENTRAL CARIBBEAN. FRESH TO LOCALLY STRONG SE
WINDS AND 5-6 FT SEAS ARE NOTED OVER THE GULF OF HONDURAS.
MODERATE E TO SE WINDS AND 4-5 FT SEAS ARE NOTED ELSEWHERE. TRADE
WIND CONVERGENCE IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS
OVER THE FAR SOUTHWEST CARIBBEAN, OFF PANAMA, COSTA RICA, AND
SOUTHEAST NICARAGUA.
FOR THE FORECAST, THE ATLANTIC RIDGE WILL REMAIN IN PLACE NORTH OF
THE AREA ALONG 27N-28N THROUGH THE UPCOMING WEEKEND WHILE WEAKENING
SLIGHTLY FRI NIGHT THROUGH SAT NIGHT, AS A FRONTAL SYSTEM CLIPS THE
WATERS OFF NE FLORIDA. THE PRESSURE GRADIENT SOUTH OF THE RIDGE WILL
SUSTAIN FRESH TO STRONG TRADE WINDS AND MODERATE TO ROUGH SEAS IN
THE SOUTH-CENTRAL CARIBBEAN THROUGH THE FORECAST PERIOD, WITH
HIGHEST WINDS AND SEAS EXPECTED OFF THE COAST OF COLOMBIA. PULSING
WINDS AT FRESH TO STRONG SPEEDS AND MODERATE TO ROUGH SEAS ARE
EXPECTED IN THE GULF OF HONDURAS NIGHTLY THROUGH MON, PULSING
BRIEFLY TO NEAR GALE-FORCE TONIGHT AND THU NIGHT. MODERATE TO FRESH
E TO SE WINDS ARE EXPECTED ELSEWHERE ACROSS THE NORTHWESTERN
CARIBBEAN THROUGH MON. ACTIVE SHOWERS AND THUNDERSTORMS ARE EXPECTED
ACROSS SW PORTIONS WED THROUGH FRI AS AN UPPER-LEVEL TROUGH DIGS
INTO THE AREA.
..ATLANTIC OCEAN
THE BERMUDA-AZORES SUBTROPICAL RIDGE IS THE DOMINANT FEATURE OF
INTEREST ACROSS THE TROPICAL ATLANTIC, AND IS INTERRUPTED ONLY BY
A FRONTAL TROUGH EXTENDING INTO THE REGION FROM THE WESTERN AZORES
TO 22N48W. THIS PATTERN IS SUPPORTING MODERATE TO LOCALLY FRESH
SOUTHERLY FLOW AND 3-6 FT SEAS OVER WEST OF 70W, GENTLE BREEZES
AND 3-5 FT SEAS NORTH OF 22N ALONG THE RIDGE AXIS, AND MODERATE
TO FRESH TRADE WINDS AND 5-6 FT SEAS SOUTH OF 22N. FRESH TO STRONG
N-NE WINDS ARE FOUND FROM 18N TO 25N BETWEEN AFRICA AND 20W WHERE
THE PRESSURE GRADIENT REMAINS TIGHT. SEAS ARE 6-7 FT IN THIS AREA.
FOR THE FORECAST WEST OF 55W, THE ATLANTIC RIDGE WILL REMAIN IN
PLACE ALONG 27N-28N THROUGH THE UPCOMING WEEKEND WHILE WEAKENING
SLIGHTLY FRI NIGHT THROUGH SAT NIGHT, AS A FRONTAL SYSTEM CLIPS THE
WATERS OFFSHORE OF NORTHEAST FLORIDA. THE RELATED PRESSURE GRADIENT
WILL MAINTAIN MODERATE TO FRESH TRADE WINDS SOUTH OF 22N THROUGH THE
FORECAST PERIOD, BUT MAINLY OFFSHORE HISPANIOLA. MODERATE TO LOCALLY
FRESH SW WINDS OFFSHORE OF NORTHEAST FLORIDA TO NEAR 72W WILL EXPAND
EASTWARD TO NEAR 65W THROUGH TONIGHT, AS A WEAK FRONTAL SYSTEM MOVES
ACROSS THE SOUTHEASTERN U.S. THE FRONT IS EXPECTED TO MOVE SLOWLY
OFFSHORE EARLY SAT AND STALL OFFSHORE NORTHEAST FLORIDA BY SUN.
EXPECT FRESH TO STRONG WINDS EACH AFTERNOON THROUGH LATE EVENING
ACROSS ATLANTIC WATERS NEAR PUERTO RICO AND HISPANIOLA.
LEWITSKY
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