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AXNT20 KNHC 261019
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1030 UTC.


...TROPICAL WAVES...

TROPICAL WAVE IS OVER THE EASTERN ATLC WITH AXIS EXTENDING FROM 18N28W TO 9N30W MOVING W AT 15-20 KT DURING THE PAST 24 HOURS. METEOSAT SAL TRACKING IMAGERY INDICATE THE WAVE CONTINUES EMBEDDED IN THE DRY SAHARAN AIRMASS WHICH IS INHIBITING CONVECTION AT THE TIME.

TROPICAL WAVE IS OVER THE WINDWARD ISLANDS AND SE CARIBBEAN WITH AXIS EXTENDING FROM 13N60W TO 8N61W MOVING W AT 20-25 KT IN THE PAST 24 HOURS. DEEP LAYER MOISTURE IN THE WAVE ENVIRONMENT IS SUPPORTING SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS FROM 9N-16N BETWEEN 55W-65W.

TROPICAL WAVE IS ON THE WESTERN CARIBBEAN WITH AXIS EXTENDING FROM 21N78W TO 10N78W 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 9N27W TO 9N35W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 9N35W TO 7N48W TO 9N55W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM 6N-9N E OF 16W...FROM 8N-10N BETWEEN 20W-35W AND FROM 6N- 10N BETWEEN 43W-52W.


...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 1017 MB HIGH NEAR 26N87W WHICH IS PROVIDING VARIABLE WINDS OF 5-15 KT ACROSS THE BASIN. AN UPPER-LEVEL CYCLONIC CIRCULATION OVER THE EASTERN GULF AND AN ANTICYCLONE CENTERED OVER THE SW N ATLC ARE GENERATING DIVERGENT WIND FLOW ALOFT OVER PORTIONS OF THE FLORIDA PENINSULA. THIS ALONG WITH MODERATE DEEP LAYER MOISTURE IS SUPPORTING ISOLATED SHOWERS AND TSTMS OVER THE SOUTH FLORIDA PENINSULA AND ADJACENT WATERS. 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 ARE GENERATING DIFFLUENT FLOW ALOFT WHICH ALONG LOW-LEVEL MOISTURE SUPPORT ISOLATED SHOWERS AND TSTMS OVER THE WINDWARD PASSAGE AS WELL AS WESTERN AND EASTERN CUBA. A TROPICAL WAVE IS MOVING OVER THE WESTERN CARIBBEAN WATERS WHILE ANOTHER WAVE ENTERS THE WINDWARD ISLANDS THIS MORNING. 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 20-30 KT S OF 17N E OF 79W WITH GALE FORCE WINDS ALONG THE COAST OF COLOMBIA. STRONG DEEP LAYER ENVIRONMENTAL WIND 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 AND TSTMS OVER THE WINDWARD PASSAGE. THIS PATTERN ALOFT ALSO SUPPORT CLOUDINESS ACROSS THE 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 SUPPORT ISOLATED SHOWERS AND TSTMS N OF 25N W OF 77W. FARTHER EAST...A MID-UPPER LEVEL LOW CENTERED NEAR 27N62W ENHANCES SCATTERED SHOWERS AND ISOLATED TSTMS FROM 23N-29N 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 STATIONARY FRONT FROM 30N31W SW TO 26N36W TO 24N43W WITH NO CONVECTION ASSOCIATED WITH IT. THE REMAINDER BASIN IS FAIRLY DRY AND UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1022 MB HIGH NEAR 38N43W. 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 TONIGHT.

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

$$ NR

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