Tropical Weather Discussion
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000 AXNT20 KNHC 261015 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE MAY 26 2015 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS W OF THE ITCZ FROM THE EQUATOR TO 11N WITH AXIS NEAR 44W...MOVING W AT 13 TO 15 KT DURING THE LAST 24 HOURS. SSMI TPW IMAGERY SHOW A DECREASE IN MOISTURE IN THE IMMEDIATE WAVE ENVIRONMENT...THUS RESULTING IN A DECREASE OF CONVECTION...ESPECIALLY ON THE NORTHERN AND EASTERN REGIONS OF THE WAVE WHERE METEOSAT IMAGERY SHOW DUST AND DRY SAHARAN AIR. SCATTERED MODERATE CONVECTION IS WITHIN 300 NM AHEAD OF THE WAVE AXIS S OF 8N. ISOLATED MODERATE CONVECTION IS WITHIN 300 NM E OF IT. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA REACHING THE TROPICAL ATLANTIC NEAR 08N12W TO 04N16W. THE ITCZ BEGINS NEAR 04N16W AND CONTINUES ALONG 04N27W TO EAST OF A TROPICAL WAVE NEAR 04N40W. ISOLATED MODERATE CONVECTION AND TSTMS ARE WITHIN 200 NM EITHER SIDE OF THE MONSOON TROUGH. ISOLATED MODERATE CONVECTION IS WITHIN 200 NM N OF THE ITCZ W OF 33W. FOR CONVECTION ASSOCIATED WITH THE TROPICAL WAVE SEE THE SECTION ABOVE. ...DISCUSSION... GULF OF MEXICO... SURFACE LOW PRESSURE EXTENDING ACROSS CENTRAL U.S. AND MEXICO EXTENDS INTO THE WESTERN GULF WHILE HIGH PRESSURE ANCHORED BY A CENTER OF 1031 MB OVER THE NW ATLANTIC CONTINUES TO EXTEND A RIDGE AXIS SW ACROSS THE FLORIDA PENINSULA INTO THE EASTERN GULF. SOUTHEASTERLY WIND FLOW OF 15 TO 20 KT ASSOCIATED WITH THE RIDGE COVERS THE GULF AND ADVECTS LOW LEVEL MOISTURE FROM THE SW N ATLC WATERS AND THE NW CARIBBEAN. LOW LEVEL MOISTURE CONVERGENCE ALONG THE N-NW GULF COASTLINE ALONG WITH A DIFFLUENT ENVIRONMENT ALOFT SUPPORT HEAVY SHOWERS AND TSTMS ASSOCIATED WITH A SQUALL LINE MOVING ACROSS SE LOUISIANA AND ADJACENT WATERS N OF 28N BETWEEN 90W AND 93W. HAZE AND FOG IS ALSO BEING REPORTED IN THE NW GULF N OF 26N W OF 90W. ISOLATED SHOWERS AND TSTMS ARE OBSERVED OVER THE NE GULF N OF 28N E OF 84W. SURFACE RIDGING WILL CONTINUE TO BE THE DOMINANT FEATURE DURING THE NEXT THREE DAYS. CARIBBEAN SEA... BROAD SURFACE HIGH PRESSURE ACROSS THE ATLANTIC CONTINUES TO EXTEND S INTO THE NORTHERN AND CENTRAL CARIBBEAN...THUS SUPPORTING A TIGHTER PRESSURE GRADIENT IN THE SW BASIN...RESULTING IN NE TO E WINDS OF 20 TO 25 KT FROM 11N TO 13N BETWEEN 73W AND 77W WITH SEAS RANGING FROM 8 TO 9 FT. ELSEWHERE FROM 11N TO 14N BETWEEN 74W AND 81W WINDS ARE 20 KT OR LESS WITH SEAS UP TO 9 FT IN E SWELL. OTHERWISE...S OF 18N W OF 85W E WINDS OF 20 TO 25 KT DOMINATE WITH SEAS LESS THAN 8 FT. SSMI TPW IMAGERY SHOW MODERATE LOW LEVEL MOISTURE OVER THE NW BASIN...WHICH ALONG WITH UPPER TROUGHING ALOFT SUPPORT ISOLATED SHOWERS AND TSTMS OVER CUBA COASTAL WATERS AND SOUTHERN WINDWARD PASSAGE. SHALLOW MOISTURE OVER THE NE CARIBBEAN SUPPORTS SCATTERED TO ISOLATED SHOWERS OVER HAITI...THE MONA PASSAGE... PUERTO RICO AND THE VIRGIN ISLANDS. FAIR WEATHER IS ELSEWHERE BEING SUPPORTED BY DEEP LAYER DRY AIR. NO SIGNIFICANT CHANGES ARE EXPECTED IN THE NEXT TWO DAYS. ...HISPANIOLA... SHALLOW MOISTURE IS OVER HAITI ENHANCING ISOLATED SHOWERS FOR THIS REGION OF THE ISLAND. DEEP LAYER DRY AIR IS OVER THE REMAINDER ISLAND AS DEPICTED BY SSMI TPW AND WATER VAPOR IMAGERY...THUS SUPPORTING FAIR WEATHER. SHOWERS AND THUNDERSTORMS ACTIVITY ARE EXPECTED DURING THE AFTERNOON AND EARLY EVENING HOURS THROUGH WED MORNING BEING ENHANCED BY OROGRAPHIC LIFTING AND DAYTIME HEATING AND SUPPORTED BY MIDDLE TO UPPER LEVEL TROUGHING. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL LOW ANCHORED NEAR 30N58W CONTINUE TO SUPPORT A SURFACE TROUGH WITH AXIS EXTENDING FROM 30N55W TO 23N61W. SCATTERED MODERATE CONVECTION AND TSTMS ARE N OF 23N BETWEEN 50W AND 58W. A TROPICAL WAVE IS W OF THE ITCZ. SEE THE TROPICAL WAVES SECTION ABOVE. ELSEWHERE SURFACE HIGH PRESSURE AND FAIR WEATHER PREVAILS. THE SURFACE TROUGH WILL DRIFT TOWARDS THE SW N ATLC DURING THE NEXT THREE DAYS. SURFACE RIDGING WILL DOMINATE ELSEWHERE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR

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