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AXNT20 KNHC 232326
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED APR 23 2014

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 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC.


...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF SENEGAL NEAR 11N16W AND TERMINATES NEAR 10N20W. THE ITCZ REACHES FROM NEAR 10N20W TO 02N30W AND TERMINATES NEAR THE MOUTH OF THE AMAZON RIVER NEAR 00N47W. CONVECTIVE PRECIPITATION...SCATTERED MODERATE CONVECTION IS NOTED FROM 01N TO 05N BETWEEN 10W AND 15W.


...DISCUSSION...


...THE GULF OF MEXICO...

DEEP LAYER RIDGING IS SHIFTING WEST THROUGH 90W NORTH OF 25N...FOLLOWING A MID TO UPPER LEVEL SHORT WAVE TROUGH THAT MOVED OFF THE EAST COAST EARLIER THIS MORNING. AN ASSOCIATED 1016 MB SURFACE HIGH IS CENTERED NEAR 27N91W. A WEAK COLD FRONT HAS BECOME STALLED ALONG THE COAST OVER THE MISSISSIPPI SOUND AND WILL LIKELY BECOME DIFFUSE THROUGH TONIGHT. OBSERVATIONS FROM BUOYS AND OIL RIGS ALONG WITH RECENT ASCAT DATA INDICATE FAIRLY LIGHT WINDS OVER ALMOST ALL OF THE BASIN THIS AFTERNOON...WITH THE EXCEPTION OF MODERATE SE RETURN FLOW SETTING UP OVER THE COAST OF TEXAS. A FEW HIGH CLOUDS ARE NOTED OVER THE EASTERN GULF LEAVING THE REMAINDER OF THE BASIN NEARLY CLOUD FREE. LOOKING AHEAD...THE HIGH PRES WILL CONTINUE TO SHIFT EASTWARD THROUGH THE WEEKEND...ALLOWING MODERATE TO FRESH RETURN FLOW TO INCREASE OVER THE NW GULF BY LATE SATURDAY.


...THE CARIBBEAN SEA...

A WEAKENED SUBTROPICAL RIDGE NORTH OF THE BASIN IS MAINTAINING GENERALLY LIGHT TO MODERATE TRADE WINDS ACROSS THE CARIBBEAN BASIN THIS AFTERNOON. THE EXCEPTION IS ALONG THE COAST OF VENEZUELA AND ABC ISLANDS WHERE WINDS TO 20 KT ARE NOTED. A THIN CANOPY OF CIRRUS EXTENDS OVER THE WESTERN CARIBBEAN PRODUCED BY CLUSTERS OF SHOWERS AND THUNDERSTORMS SOUTH OF PANAMA AND ACROSS NORTHERN SOUTH AMERICA...SPECIFICALLY LARGE AREAS OF MODERATE TO STRONG THUNDERSTORMS OVER NE COLOMBIA AND NW VENEZUELA. THESE THUNDERSTORMS ARE MOVING NORTHWARD AND ARE STARTING TO IMPACT COASTAL AREAS FROM CARTAGENA COLOMBIA THROUGH LAKE MARACAIBO IN VENEZUELA. A FEW SHOWERS ARE LIKELY OVER EASTERN CARIBBEAN WITHIN 150 NM DOWNSTREAM OF THE HIGHER PEAKS IN THE WINDWARD ISLANDS. LOOKING AHEAD...HIGH PRES WILL BUILD N OF THE AREA THIS WEEKEND...ALLOWING TRADE WINDS TO INCREASE OVER THE SOUTH CENTRAL CARIBBEAN AND GULF OF HONDURAS.


...HISPANIOLA...

DEEP LAYER MOISTURE IS POOLING ALONG A STALLED SURFACE TROUGH EXTENDS FROM THE N CENTRAL ATLC ACROSS NW HAITI AND THE WINDWARD PASSAGE TO SOUTH OF GRAND CAYMAN. UPPER FORCING RELATED TO AN ACTIVE SOUTHERN STREAM JET EXTENDING NW OF HISPANIOLA OVER CENTRAL CUBA AND THE BAHAMAS IS ENHANCING AFTERNOON CONVECTION OVER THE HIGHER TERRAIN OF HISPANIOLA...AS WELL AS OVER EASTERN CUBA AND JAMAICA. SHOWERS AND THUNDERSTORMS WILL TAPER OFF THIS EVENING. THE TROUGH WILL BECOME DIFFUSE THROUGH TONIGHT...WITH SOMEWHAT LESS SHOWER AND THUNDERSTORM ACTIVITY REPEATING OVER THE NEXT COUPLE OF DAYS. LOOKING AHEAD...THE TRAILING END OF A WEAK COLD FRONT PASSING EASTWARD TO THE NORTH OF HISPANIOLA WILL DRIFT TO THE NORTHERN COAST OF HISPANIOLA BY SUNDAY. THIS WILL COINCIDE WITH THE ARRIVAL OF WEAK TROUGH IN THE MID TO UPPER LEVELS...ALLOWING FOR INCREASED SHOWERS AND INLAND THUNDERSTORMS BY SUNDAY.


...THE ATLANTIC OCEAN...

A BROAD MID TO UPPER LEVEL TROUGH CONTINUES TO MOVE EASTWARD OVER THE NW ATLANTIC...REACHING FROM NEW ENGLAND TO AROUND 27N WEST OF 70W. THIS IS INTERACTING WITH A STALLED SURFACE TROUGH...THE REMNANTS OF A COLD FRONT...EXTENDING FROM 31N55W TO NW HAITI. A FEW SHOWERS ARE POSSIBLE ALONG THIS SURFACE TROUGH. A FEW SHOWERS AND THUNDERSTORMS ARE EMBEDDED IN LARGE AREAS OF MID TO UPPER LEVEL CLOUDINESS AHEAD OF THE MID/UPPER TROUGH N OF 25N BETWEEN 70W AND 40W. GENERALLY DRY CONDITIONS PREVAIL WEST OF 70W. A COLD FRONT NORTH OF THE AREA WILL DRIFT SE ACROSS THE WATERS NORTH OF 25N THROUGH SATURDAY FOLLOWED BY MODERATE RIDGING. THIS WILL INCREASE TRADE WIND FLOW S OF 22N W OF 60W THIS WEEKEND.

FARTHER EAST...ASCAT SATELLITE DATA AND SHIP OBSERVATIONS SHOW A BROAD SURFACE RIDGE REACHING FROM 32N35W TO THE LEEWARD ISLANDS. FRESH TO STRONG SOUTHERLY FLOW IS NOTED NORTH OF 25N BETWEEN THE RIDGE AXIS AND THE SURFACE TROUGH TO THE WEST...WITH SEAS TO 9 FT AS NOTED BY ALTIMETER SATELLITE PASSES. FRESH TRADE WINDS ARE NOTED SOUTH OF THE RIDGE AXIS...NAMELY SOUTH OF 15N WEST OF 35W. ALTIMETER SATELLITE PASSES OVER THE PAST SEVERAL HOURS INDICATED SEAS TO 8 FT IN THIS AREA. MODERATE TO FRESH NE FLOW IS NOTED OVER THE FAR EASTERN TROPICAL ATLC WATERS EAST OF 35W TO THE COAST OF AFRICA WITH NO SIGNIFICANT CLOUDINESS NOTED NORTH OF 10N. MINIMAL TRADE WIND CONVERGENCE IS INHIBITING SIGNIFICANT CONVECTION ALONG THE ITCZ...ALTHOUGH WEAK UPPER DIVERGENCE AHEAD OF AN APPROACHING UPPER TROUGH IS ENHANCING AREAS OF SHOWERS AND THUNDERSTORMS IN THE DEEP TROPICS SOUTH OF 10N EAST OF 25W.

FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE

$$ CHRISTENSEN

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