608
AXNT20 KNHC 181704
TWDAT
TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1805 UTC THU APR 18 2024
TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA, CENTRAL AMERICA
GULF OF MEXICO, 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
1600 UTC.
..MONSOON TROUGH/ITCZ
THE MONSOON TROUGH IS CONFINED TO THE AFRICAN CONTINENT THIS
MORNING, AND REACHES NEAR THE COAST OF SIERRA LEONE NEAR 08N13W.
THE ITCZ EXTENDS FROM 06N14.5W TO 05N22W TO 01S38W TO COASTAL
BRAZIL NEAR 00.5S49W. SCATTERED MODERATE TO STRONG CONVECTION IS
OBSERVED SOUTH OF 02N AND BETWEEN 29W AND 48W, AND WITHIN 300 NM
OF THE COAST BETWEEN 48W AND 58W.
..GULF OF MEXICO
A SUBTROPICAL RIDGE OVER THE WESTERN ATLANTIC EXTENDS WESTWARD
INTO THE NE BASIN, WITH THE ASSOCIATED RIDGE DOMINATING THE GULF
OF MEXICO. THIS PATTERN SUPPORTS MODERATE TO FRESH E TO SE WINDS
OVER THE MUCH OF THE BASIN, WITH THE STRONGEST WINDS OCCURRING OFF
W YUCATAN. MODERATE SEAS OF 6 FT OR LESS ARE PREVALENT ACROSS THE
BASIN, EXCEPT FOR SLIGHT SEAS IN THE NE GULF. SCATTERED LIGHT TO
MODERATE SHOWERS CONTINUE TO AFFECT THE NW GULF WATERS OFFSHORE OF
TEXAS.
FOR THE FORECAST, HIGH PRESSURE WILL PERSIST ACROSS THE BASIN AND
PRODUCE A MOIST RETURN FLOW ACROSS THE NORTHERN GULF, LIKELY TO
LEAD TO PATCHY AREAS OF FOG AT NIGHT THROUGH SAT. FRESH TO STRONG
WINDS NORTHEAST TO EAST WINDS WILL CONTINUE PULSING OFF THE NW
YUCATAN PENINSULA AND SOUTH- CENTRAL GULF AT NIGHT THROUGH SAT
NIGHT. LOOKING AHEAD, A COLD FRONT IS FORECAST TO MOVE INTO THE NW
GULF SUN MORNING, REACH FROM TAMPA BAY TO 25N90W TO 22N95W EARLY
MON AND EXIT THE BASIN MON NIGHT. MODERATE TO FRESH NORTHEAST
WINDS WILL FOLLOW THE FRONT, EXCEPT BRIEFLY REACHING STRONG SPEEDS
OVER THE WATERS EAST OF SOUTHERN TEXAS SUN NIGHT.
..CARIBBEAN SEA
THE SUBTROPICAL RIDGE OVER THE WESTERN ATLANTIC CONTINUES TO FORCE
FRESH TO LOCALLY STRONG TRADE WINDS IN THE LEE OF CUBA, THE WINDWARD
PASSAGE AND SOUTH OF HISPANIOLA. SEAS IN THESE WATERS ARE 4-7 FT.
A DEEP LAYERED TROUGH EXTENDS FROM THE CENTRAL ATLANTIC
SOUTHWESTWARD TO THE NORTH-CENTRAL CARIBBEAN, AND INTERRUPTS
ATLANTIC RIDGING INTO THE EASTERN CARIBBEAN. MODERATE TO LOCALLY
FRESH EASTERLY WINDS AND SEAS OF 3-5 FT ARE EVIDENT IN THE SOUTH-
CENTRAL AND SE CARIBBEAN AND REMAINDER OF THE NW CARIBBEAN. SMALL
CLUSTERS OF LIGHT TO MODERATE SHOWERS EXTEND FROM THE EASTERN
CARIBBEAN NORTHEASTWARD ACROSS THE SOUTHERN LEEWARD ISLANDS.
MOISTURE ASSOCIATED WITH THE OLD REMNANTS OF A FRONTAL TROUGH ARE
PRODUCING CLUSTERS OF BROKEN TO OVERCAST CLOUDS AND SCATTERED
SHOWERS EXTENDING FROM SW HAITI WESTWARD TO JUST NORTH OF THE GULF
OF HONDURAS.
FOR THE FORECAST, ATLANTIC HIGH PRESSURE LOCATED BETWEEN BERMUDA
AND THE BAHAMAS WILL SUPPORT FRESH TO LOCALLY STRONG TRADE WINDS
IN THE LEE OF CUBA AND WINDWARD PASSAGE AT NIGHT DURING THE NEXT
FEW DAYS. THESE WINDS WILL GRADUALLY DIMINISH THIS WEEKEND INTO
EARLY NEXT WEEK AS A COLD FRONT MOVES ACROSS THE WESTERN ATLANTIC
AND THE HIGH PRESSURE DRIFTS SE AND WEAKENS. HIGH PRESSURE
BUILDING IN BEHIND THE FRONT IS EXPECTED TO SUPPORT FRESH TO
LOCALLY STRONG TRADE WINDS IN THE SOUTH-CENTRAL CARIBBEAN STARTING
MON.
..ATLANTIC OCEAN
DEEP LAYERED UPPER LEVEL TROUGHING FROM THE CENTRAL ATLANTIC TO
THE NORTH-CENTRAL CARIBBEAN CONTINUES TO SUPPORT A SURFACE TROUGH,
CURRENTLY ANALYZED FROM 30N51W TO 1012 MB LOW PRESSURE NEAR
22.5N57W CONTINUING TO 19N62W. SCATTERED MODERATE CONVECTION IS
NOTED NORTH OF 23N AND BETWEEN 47W AND THE SURFACE TROUGH. HIGH
PRESSURE OF 1021 MB IS CENTERED ACROSS THE NW WATERS NEAR 30N72W.
THE PRESSURE GRADIENT BETWEEN THE HIGH AND THE LOW HAS DECREASED
IN THE PAST SEVERAL HOURS, LEADING TO MODERATE TO FRESH WINDS AND
SEAS OF 5-8 FT FROM S OF 28N AND BETWEEN THE BAHAMAS AND THE
SURFACE TROUGH. ELSEWHERE WEST OF 55W, MODERATE OR WEAKER WINDS
AND MODERATE SEAS ARE PREVALENT.
TO THE EAST OF THE SURFACE TROUGH, THE CENTRAL AND EASTERN
ATLANTIC ARE UNDER THE INFLUENCE OF A 1021 MB HIGH PRESSURE
SYSTEM POSITIONED NEAR 26N38W. THE PRESSURE GRADIENT BETWEEN THIS
RIDGE AND LOWER PRESSURES IN THE DEEP TROPICS SUPPORTS MODERATE
TO LOCALLY FRESH NE TO E TRADE WINDS SOUTH OF 20N AND BETWEEN 28W
AND 55W. WAVE HEIGHTS ARE 6-9 FT IN THIS AREA. SATELLITE IMAGERY
SUGGESTS THAN SAHARAN AIR DOMINATES THIS AREA S OF 20N BETWEEN
AFRICA AND 45W. SLIGHT TO GENTLE WINDS AND MODERATE SEAS PREVAIL
IN THE REST OF THE BASIN.
FOR THE FORECAST W OF 55W, THE TROUGH AND LOW PRESSURE LOCATED NE
OF THE CARIBBEAN WILL MOVE NORTHEAST OF THE FORECAST AREA THIS
AFTERNOON. WINDS WILL DIMINISH AND SEAS WILL SUBSIDE OVER THESE
WATERS AS THIS SYSTEM MOVES AWAY, ALLOWING FOR THE PRESSURE
GRADIENT TO RELAX. LOOKING AHEAD, MODERATE TO FRESH SOUTHERLY
WINDS WILL DEVELOP OVER THE FLORIDA OFFSHORE WATERS N OF THE NW
BAHAMAS STARTING SUN AFTERNOON, AHEAD OF A COLD FRONT FORECAST TO
MOVE OFF NE FLORIDA SUN NIGHT. THESE WINDS WILL REACH STRONG
SPEEDS SUN NIGHT AND DIMINISH TO MODERATE TO FRESH SPEEDS MON.
STRIPLING
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