790  
AXNT20 KNHC 200004  
TWDAT  
 
TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL  
804 PM EDT TUE JUN 19 2018  
 
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  
2300 UTC.  
   
..SPECIAL FEATURE
 
 
SURFACE OBSERVATIONS AND NOAA DOPPLER WEATHER RADAR DATA INDICATE  
THAT A DEEP LAYER LOW PRESSURE SYSTEM HAS CONSOLIDATED W OF  
CORPUS CHRISTI TEXAS NEAR 28N98W. THIS SYSTEM HAS BEEN PRODUCING  
WIDESPREAD CLOUDINESS AND DISORGANIZED RAINSHOWERS. INTERACTION  
WITH LAND AND PROXIMITY TO DRY AIR IN THE MID-LEVELS OF THE  
ATMOSPHERE IN W TEXAS AND NE MEXICO SHOULD PREVENT A TROPICAL  
CYCLONE FROM FORMING. IT IS LIKELY THAT THIS DISTURBANCE MAY  
PRODUCE ADDITIONAL HEAVY RAINFALL AND FLASH FLOODING ACROSS  
PARTS OF SOUTHERN AND SOUTHEASTERN TEXAS DURING THE NEXT FEW  
DAYS. AS MUCH AS 7 TO 10 INCHES OF ADDITIONAL RAINFALL ARE  
POSSIBLE IN SOUTH TEXAS ALONG THE TEXAS COASTAL BEND DURING THE  
NEXT 1 TO 2 DAYS. STRONG SE TO S WINDS CAN BE EXPECTED IN THE  
WESTERN GULF N OF 25N BETWEEN 92W AND 96W, PRIMARILY IN BANDS OF  
DEEP CONVECTIVE PRECIPITATION THROUGH THIS EVENING. WINDS AND  
SEAS ARE EXPECTED TO SUBSIDE TONIGHT AND WEDNESDAY AS THIS SYSTEM  
GRADUALLY WEAKENS. NUMEROUS STRONG RAINSHOWERS ARE IN TEXAS AND  
NORTHEASTERN PARTS OF MEXICO FROM 24N TO 27N BETWEEN THE COAST AND  
99W. SCATTERED MODERATE TO ISOLATED STRONG RAINSHOWERS ARE IN THE  
GULF OF MEXICO FROM 26N NORTHWARD FROM 91W WESTWARD. PLEASE READ  
BULLETINS AND FORECASTS THAT ARE ISSUED BY YOUR LOCAL WEATHER  
OFFICE, AND HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER  
SERVICE FOR MORE DETAILS ON THIS DISTURBANCE AND THE THREAT FOR  
HEAVY RAINFALL.  
   
..TROPICAL WAVES
 
 
 
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 21W/22W FROM 11N  
SOUTHWARD, MOVING W ABOUT 20 KT, IN A LOW VERTICAL SHEAR  
ENVIRONMENT. COMPOSITE TPW SATELLITE IMAGERY SHOWS THIS SYSTEM IS  
EMBEDDED IN DEEP LAYER MOISTURE. SCATTERED MODERATE AND ISOLATED  
STRONG CONVECTION IS FOUND FROM 03N TO 06N BETWEEN 18W AND 21W.  
 
A SECOND ATLANTIC OCEAN TROPICAL WAVE IS ALONG 34W/35W FROM 11N  
SOUTHWARD, MOVING W ABOUT 15 KT, IN A MODERATE SHEAR ENVIRONMENT  
DUE TO AN UPPER-LEVEL TROUGH IN THE ATLC NEAR 40W. DRY SAHARAN  
AIR AND DUST ARE LIMITING CONVECTION ON THE W SIDE OF THIS WAVE.  
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FOUND FROM  
03N TO 06N BETWEEN 27W AND 36W.  
 
A THIRD ATLANTIC OCEAN TROPICAL WAVE IS ALONG 51W/54W FROM 14N  
SOUTHWARD, MOVING W ABOUT 10 KT. GOES-16 RGB IMAGERY SHOWS DRY  
AIR AND DUST SURROUNDING THE N SIDE OF THE WAVE. CONVERGENT UPPER-  
LEVEL WINDS ARE ALSO INHIBITING DEEP CONVECTION. CONSEQUENTLY,  
ONLY SPOTTY CLOUDINESS AND ISOLATED SHOWERS ARE OBSERVED WITHIN 90  
NM OF THE WAVE AXIS.  
 
A CARIBBEAN SEA TROPICAL WAVE IS ALONG 63W/67W FROM 19N SOUTHWARD,  
MOVING W 15 TO 20 KT. THIS WAVE IS WITHIN A VERY MOIST  
ENVIRONMENT AND UPPER LEVEL DIFFLUENT FLOW, SUPPORTING SCATTERED  
MODERATE AND ISOLATED STRONG CONVECTION OVER THE VIRGIN ISLANDS  
AND LEEWARD ISLANDS FROM 12N TO 19N BETWEEN 61W AND 65W.  
   
..MONSOON TROUGH/ITCZ
 
 
 
THE MONSOON TROUGH PASSES THROUGH THE COASTAL SECTIONS OF GUINEA  
NEAR 10N14W, TO 06N23W. THE ITCZ CONTINUES FROM 06N23W TO 04N31W  
05N33W, TO 04N53W IN NE FRENCH GUIANA. SCATTERED MODERATE AND  
ISOLATED STRONG CONVECTION IS PRESENT FROM 03N TO 07N BETWEEN 10W  
AND 18W.  
   
..DISCUSSION
 
 
GULF OF MEXICO...  
 
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE OCCURRING OVER  
THE GULF OF MEXICO W OF 92W. THIS CONVECTION IS ASSOCIATED WITH  
DEEP LAYER LOW PRESSURE CENTERED OVER S TEXAS. SEE THE SPECIAL  
FEATURES SECTION FOR MORE DETAILS ON THIS SYSTEM. THE PRESSURE  
GRADIENT BETWEEN THE AREA OF LOW PRESSURE AND A RIDGE ACROSS THE  
SE CONUS EXTENDING INTO THE NE GULF SUPPORTS FRESH TO STRONG SE TO  
S WINDS W OF 87W. LIGHT TO MODERATE E TO SE WINDS ARE OBSERVED  
OVER THE EASTERN GULF. THE RIDGE OVER THE GULF WILL GRADUALLY  
SHIFT E OVER THE WESTERN ATLC DURING THEN NEXT COUPLE OF DAYS,  
HELPING WINDS OVER THE WESTERN GULF TO DIMINISHING BELOW 20 KT.  
GENTLE TO MODERATE RETURN FLOW WILL DOMINATE THE BASIN THEREAFTER  
THROUGH WED NIGHT, WITH STRONGEST WINDS FOCUSING WEST OF 90W.  
 
CARIBBEAN SEA...  
 
STRONG TRADES ACROSS THE S CENTRAL CARIBBEAN WILL GRADUALLY  
DECREASE IN AREAL COVERAGE TODAY THROUGH WED AS HIGH PRESSURE IN  
THE SW N ATLC SHIFTS EAST. FRESH TO STRONG WINDS WILL PULSE AT  
NIGHT IN THE GULF OF HONDURAS THROUGH EARLY WED MORNING.  
OTHERWISE, A TROPICAL WAVE PASSING WEST OF THE WINDWARD ISLANDS  
WILL MOVE ACROSS THE E CARIBBEAN TODAY ALONG WITH SHOWERS. THE  
WAVE WILL MOVE S OF PUERTO RICO, THEN INTO THE CENTRAL CARIBBEAN  
ON WED. WINDS AND SEAS OVER THE S CENTRAL CARIBBEAN WILL INCREASE  
TOWARD THE END OF THE WEEK AS HIGH PRESSURE OVER THE WESTERN ATLC  
REBUILDS AND LOW PRESSURE OVER NORTHERN S AMERICA DEEPENS  
SLIGHTLY.  
 
ATLANTIC OCEAN...  
 
A STATIONARY FRONT EXTENDS SW FROM 32N56W TO 26N63W, THEN  
CONTINUES W AS A WEAKENING STATIONARY FRONT TO END JUST EAST OF  
THE BAHAMAS NEAR 25N74W. WEAK SURFACE RIDGING NORTH OF THE FRONT  
SUPPORTS LIGHT TO GENTLE NE TO E WINDS AND MOSTLY FAIR WEATHER.  
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS SEEN FROM 24N  
TO 29N BETWEEN 55W AND 68W. A MID TO UPPER-LEVEL LOW CONTINUES TO  
SUPPORT CONVECTION IN THE VICINITY OF THE FRONT. THE REMAINDER OF  
THE ATLANTIC REMAINS UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE  
ANCHORED BY A 1027 MB HIGH CENTERED JUST SW OF THE AZORES  
ISLANDS. THE FRONT WILL CONTINUE TO WEAKEN THROUGH TUE AND  
DISSIPATE BY WED. SURFACE RIDGING WILL CONTINUE TO EXTEND SW OVER  
THE WESTERN ATLC FROM NEAR THE AZORES THROUGH THE END OF THE  
WEEK.  
 
FOR ADDITIONAL INFORMATION PLEASE VISIT  
HTTP://WWW.HURRICANES.GOV/MARINE  
 

 
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