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000
AXNT20 KNHC 260603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT JUL 26 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0545 UTC.


...TROPICAL WAVES...

TROPICAL WAVE IS OVER THE EASTERN ATLC WITH AXIS EXTENDING FROM 19N27W TO 10N28W MOVING W AT 20 KT. METEOSAT SAL TRACKING IMAGERY INDICATE THE WAVE CONTINUES EMBEDDED IN THE DRY SAHARAN AIRMASS WHICH IS INHIBITING CONVECTION AT THE TIME.

TROPICAL WAVE IS APPROACHING THE WINDWARD ISLANDS WITH AXIS EXTENDING FROM 13N57W TO 7N59W MOVING W AT 20 KT IN THE PAST 24 HOURS. DEEP LAYER MOISTURE IN THE WAVE ENVIRONMENT IS SUPPORTING SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS FROM 6N-13N BETWEEN 54W-63W.

TROPICAL WAVE IS ON THE WESTERN CARIBBEAN WITH AXIS EXTENDING FROM 20N77W TO 10N77W MOVING W AT 20 KT DURING THE PAST 24 HOURS. MODERATE LOW-LEVEL MOISTURE IS NOTED IN THE WAVE ENVIRONMENT...HOWEVER DRY AIR SUBSIDENCE FROM ALOFT AND STRONG DEEP LAYER ENVIRONMENTAL SHEAR HINDER THE DEVELOPMENT OF CONVECTION.


...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF WEST AFRICA NEAR 12N16W AND THEN CONTINUES ALONG 9N25W TO 8N38W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 8N38W TO 8N50W TO 8N57W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM 6N-9N E OF 16W...FROM 7N-11N BETWEEN 20W-34W AND FROM 6N- 10N BETWEEN 37W-48W.


...DISCUSSION...

GULF OF MEXICO...

LOW-LEVEL MOISTURE ACROSS THE GULF HAS SLIGHTLY REDUCED IN THE LAST COUPLE OF HOURS WHICH ALONG MIDDLE-LEVEL AND SURFACE RIDGING CONTINUE TO SUPPORT STABILITY AND MAINLY CLEAR SKIES BASIN-WIDE. THE SURFACE RIDGE IS BEING ANCHORED BY A 1019 MB HIGH NEAR 26N87W WHICH IS PROVIDING VARIABLE WINDS OF 5-15 KT ARE ACROSS THE BASIN. DIFFLUENCE ALOFT IS BEING GENERATED BY AN UPPER-LEVEL CYCLONIC CIRCULATION OVER THE EASTERN GULF AND AN ANTICYCLONE CENTERED OVER THE SW N ATLC. THIS ALONG WITH MODERATE DEEP LAYER MOISTURE IS SUPPORTING SCATTERED SHOWERS OVER THE CENTRAL AND SW FLORIDA PENINSULA. SURFACE RIDGING AND FAIR WEATHER IS FORECAST ACROSS MUCH OF THE BASIN FOR THE NEXT TWO DAYS. SHOWERS ARE EXPECTED FOR THE SW GULF MONDAY MORNING AS A TROPICAL WAVE MOVES TOWARDS THE BAY OF CAMPECHE.

CARIBBEAN SEA...

AN ANTICYCLONE CENTERED OVER THE SW N ATLC ALONG WITH AN INVERTED TROUGH OVER THE CENTRAL CARIBBEAN IS GENERATING DIFFLUENCE ALOFT WHICH ALONG LOW-LEVEL MOISTURE IS SUPPORTING SCATTERED SHOWERS OVER SW HAITI...WINDWARD PASSAGE AND CENTRAL CUBA. THE INVERTED TROUGH ALOFT AND THE WESTERN PERIPHERY OF A RIDGE CENTERED SE OF THE LESSER ANTILLES GENERATE DIFFLUENT FLOW AS WELL WHICH IS SUPPORTING CLOUDINESS AND ISOLATED SHOWERS ACROSS PUERTO RICO AND ADJACENT WATERS. A TROPICAL WAVE IS MOVING OVER THE WESTERN CARIBBEAN WATERS WHILE ANOTHER WAVE APPROACHES THE WINDWARD ISLANDS. SEE TROPICAL WAVE SECTION FOR DETAILS. THE PASSAGE OF THE TROPICAL WAVE ACROSS THE CENTRAL CARIBBEAN ALONG WITH THE CONTINUATION OF A TIGHT PRESSURE GRADIENT IN THE REGION SUPPORT TRADES OF 20-25 KT S OF 17N E OF 81W WITH NEAR GALE FORCE WINDS ALONG THE COAST OF COLOMBIA. STRONG DEEP LAYER ENVIRONMENTAL SHEAR AND DRY AIR SUBSIDENCE FROM ALOFT SUPPORT CLEAR SKIES ACROSS THE REMAINDER BASIN. THE WESTERNMOST TROPICAL WAVE IS FORECAST TO MOVE ACROSS THE YUCATAN PENINSULA BY MON MORNING WHILE THE SECOND WAVE MOVES S OF PUERTO RICO.


...HISPANIOLA...

AN ANTICYCLONE CENTERED OVER THE SW N ATLC ALONG WITH AN INVERTED TROUGH OVER THE CENTRAL CARIBBEAN IS GENERATING DIFFLUENCE ALOFT WHICH ALONG LOW-LEVEL MOISTURE IS SUPPORTING SCATTERED SHOWERS OVER SW HAITI AND THE WINDWARD PASSAGE. THIS PATTERN ALOFT ALSO SUPPORT CLOUDINESS ACROSS THE REMAINDER ISLAND. EXCEPT FOR AFTERNOON/EARLY EVENING SHOWERS...FAIR WEATHER IS FORECAST FOR THE ISLAND SAT AND SUN.

ATLANTIC OCEAN...

A DIFFLUENT ENVIRONMENT ALOFT BEING GENERATED BY AN UPPER-LEVEL CYCLONIC CIRCULATION OVER THE EASTERN GULF AND AN ANTICYCLONE CENTERED OVER THE SW N ATLC IS SUPPORTING ISOLATED SHOWERS AND TSTMS N OF 28N BETWEEN 78W-79W. FARTHER EAST...A MID-UPPER LEVEL LOW ENHANCES SCATTERED SHOWERS N OF 23N BETWEEN 59W-67W. OVER THE E ATLC...A MID-UPPER LEVEL LOW N OF THE AREA EXTENDS A TROUGH SW WITH A BASE NEAR 24N. THIS CYCLONIC CIRCULATION AND ASSOCIATED TROUGH SUPPORT A FRONTAL BOUNDARY ANALYZED AS A COLD FRONT FROM 30N30W SW TO 26N37W TO 25N43W WITH NO CONVECTION ASSOCIATED WITH IT. THE REMAINDER BASIN IS FAIRLY DRY AND UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1025 MB HIGH NEAR 30N55W. THESE TWO FACTORS SUPPORTS FAIR WEATHER ELSEWHERE IN THE BASIN. OTHERWISE...SEE ABOVE THE TROPICAL WAVES SECTION. SURFACE RIDGING WILL DOMINATE ACROSS THE CENTRAL AND WESTERN ATLC. THE FRONT IS FORECAST TO DISSIPATE MON.

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

$$ NR

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