Atlantic Tropical Weather Discussion

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 
WWW.HURRICANES.GOV/MARINE

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NR